Library

Notes: 1-β-D-Glucopyranosyl-thymin 1 und 1-β-D-Galaktopyranosyl-thymin 13 ergeben mit äquimolaren Tosyl-oder Mesylchlorid bevorzugt die entsprechenden 6′-O-Sulfonyl-Nucleoside 6 und 7 bzw. 14 und 15. In geringer Menge entstehen die 2′,6′-Di-O-sulfonyl-Derivate 4 und 5. Während in der Glucose-Reihe besonders die Tosylverbindung leicht mit Alkalifluorid zum 6′-Desoxy-6′-fluor-Nucleosid 10 reagiert, gelingt die analoge Substitution in der Galaktose-Reihe nur schwer.Die Kondensation 2,3,4-Tri-O-acetyl-6-O-tosyl-D-glucopyranosylbromid 2 bzw. von 1,2,3,4-Tetra-O-acetyl-6-desoxy-6-fluor-D-galaktose 18 mit 2,4-Bis-O-trimethylsilyl-thymin 3 führt zu Nucleosiden, die nach der Entacetylierung mit 6 bzw. 1-(6′-Desoxy-6′-fluor-β-D-galaktopyranosyl)-thymin 20 identisch sind.

Notes: ortho-P(O)-substituierte Phenole 4 sind im Gegensatz zu offenkettigen Phosphoryl-enolen 1 durch Spaltung der Phenol-alkyl-äther gut zugänglich und als Studienobjekte für die gegenseitige Beeinflussung der P = O- und der OH-Gruppe in 1.2-Position einer C=C-Doppelbindung geeignet. Rf(DC)-Werte deuten darauf hin, daß die Phenole 4 in Lösung bei ausreichender Basizität des Phosphoryl-O-Atoms Wasserstoffbrückenbindungen P=O ⃛ H-O ausbilden, während stark elektronenziehende P-Substituenten die Beteiligung der P=O-Gruppe unwahrscheinlich machen. δOH- und Pka-Werte zeigen, daß in Dimethylsulfoxid nur im ersten Fall (Phosphinoxide 4a-g) P=O ⃛ HO-Brücken existieren, während bei Phosphonsäure-arylestern 4i-k Addukte mit DMSO-Molekülen gebildet werden. Für diese Differenzierung sind in erster Linie induktive Substituenten-effekte verantwortlich. Die UV-Spektren deuten lediglich einen geringen konjugativen Beitrag von P-Phenylsubstituenten an.

Notes: Die anodischen und kathodischen Halbstufenpotentiale in Acetonitril bzw. Dimethylformamid (DMF) sowie die Absorptions- und Fluoreszenzspektren in DMF und Cyclohexan von 61 N-Aryl-Δ2-pyrazolinen wurden gemessen. Zwischen der Differenz der Halbstufenpotentiale E1/2ox  -  E1/2red der ersten Oxydations- und Reduktionsstufe und dem Fluoreszenzmaximum in DMF h ·maxf besteht folgender Zusammenhang, der den Charge-Transfer-Charakter des entsprechenden spektroskopischen Überganges bestätigt: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm h} \cdot v_{{\rm max}}^{\rm f} = {\rm E}_{{\rm 1/2}}^{{\rm ox}} - {\rm E}_{{\rm 1/2}}^{{\rm red}} - 0,45 \pm 0,04[{\rm eV}] $$\end{document} Die Abweichungen einiger Verbindungen von dieser Beziehung sind auf strukturbedingt veränderte elektrochemische Eigenschaften wie z. B. die kathodische Halogenidabspaltung der halogensubstituierten Pyrazoline oder die Bildung einer intramolekularen Wasserstoffbrücke bei den 1, 5-Diaryl-3-o-hydroxyphenyl-Δ2-pyrazolinen zurückzuführen.

Notes: Durch radikalische Addition von Triäthylstannan an Alkenylphosphon-und -phosphinsäureester werden ω-Triäthylstannylalkylphosphon- und -phosphinsäureester 1 synthetisiert, die durch Umsetzung mit Brom bzw. Chlorwasserstoff unter Substitution eines Äthylrestes die Organozinnhalogenide 2 und 3 liefern. Aus der alkalischen Hydrolyse der stannyl-substituierten Phosphinsäureester resultieren die Säuren 4, die in die cyclischen Organozinnphosphinate 5 überführbar sind. Lithiumalanat reduziert ω-Triäthylstannylalkylphosphon- und -phosphinsäureester zu ω-Triäthylstannylalkylphosphinen 6, deren P-phenylsubstituierte Vertreter durch Schwefel über die Dithiosäuren 8 zu 1-Diäthyl-3-phenyl-1,2,3-stannathiaphospholan- bzw. -phosphorinan-P-sulfid 9 oxydiert werden.

Notes: Aminomethan-bis-phosphonsäure-tetraäthylester wurden nach verschiedenen Verfahren synthetisiert. Die Chlorierung und die Hydrolyse dieser Verbindungen wurden eingehend untersucht.

Notes: Es wird die Synthese einer Anzahl neutraler und basischer Amide der Gibberellin-A3- und -A1-Reihe durch Aminolyse entsprechender Gibberellinanhydride beschrieben. Massen- und 1H-NMR-spektroskopische Befunde an dieser Verbindungsklasse werden mitgeteilt.

Notes: Nach verschiedenen Synthesemethoden wurden lineare Poly-n-alkylmethylsiloxane (CH3)3-[OSi(CH3)R]n-OSi(CH3)3 mit R = C12H25, C14H29, C16H33 und n ≤ 8 hergestellt. Sie erwiesen sich in Erdölmitteldestillaten ebenso wie die analogen cyclischen Siloxanderivate [OSi(CH3)R]m (m = 3…6) als wirksame Stockpunkterniedriger und zeigten darüber hinaus die relativ seltene Fähigkeit der BPA-Punktdepression.Einige Überlegungen zum Wirkungsmechanismus der BPA-Punktdepression werden mitgeteilt.

Notes: Azidionen reagieren mit 1.3-Dithioliumsalzen 1 zu 2-Azido-1.3-dithiolen 2. 2-Azido-2-methylmercapto-1.3-dithiole vom Typ 2a spalten in Lösung bereits bei Raumtemperatur Stickstoff ab, wobei sich neben N-Methylmercapto-2-imino-1.3-dithiols 4 3-Methylmercapto-1.4.2-dithiazine 5a, c-1 bilden. Die Thermolyse des stabileren 2-Azido-1.3-dithiols 2b verläuft weniger übersichtlich. Als Sulfenimide lassen sich die 4 leicht zu 2-Amino-1.3-dithioliumsalzen 6 spalten. Die 1.4.2-Dithiazine 5 sind thermoinstabil. Sie gehen unter Schwefelextrusion in Isothiazole 11 über. Gleichzeitig spaltet sich aus den 5a, c-k Methylrhodanid bzw. aus 5b Blausäure ab. Als Intermediärprodukt wurde ein Dithiet bzw. Dithioketon durch Abfang mit Fumarsäuredimethylester wahrscheinlich gemacht. Mit stark elektrophilen Reagenzien setzen sich die 5 unter Ringverengung zu 1.3-Dithiol-Derivaten und mit starken Basen unter Ringspaltung um.

Notes: Es wird eine einfache und ökonomische Synthese von D, L-Phosphinothricin 2, dem wirksamen Bestandteil eines aus Streptomyces viridochromogenes isolierten antibiotisch wirksamen Heterotripeptids beschrieben.

Notes: Aromatische Kohlenwasserstoffe lassen sich mit 1.3-Bis-chlormethyl-benzimidazolon 3 und mit 1.3-Bis-chlormethyl-benzimidazolthion 4 bei Gegenwart von Aluminiumchlorid zu 1.3-Bis-arylmethyl-benzimidazolonen 5-6 bzw. zu 1.3-Bis-arylmethyl-benzimidazolthionen 7-9 amidomethylieren. Die Amidomethylierung von Natrium- oder Kalium-phenolaten mit 3 und 4 führt zu den 1.3-Bis-aryloxymethyl-benzimidazolonen 10-12 bzw. zu entsprechenden Benzimidazolthionen 13-16, die zur Charakterisierung der Phenole geeignet sind.

Notes: N-Acyl-, N-Thioacyl- und N-Sulfonyl-substituierte Thiophosphinsäureamide werden durch Reaktion metallierter Säureamide mit Säurechloriden erhalten. Die Verbindungen liegen als Imide vor und bilden im festen Zustand intermolekulare Wasserstoffbrücken. Ihre potentiometrisch bestimmten Aciditätskonstanten zeigen einen beträchtlichen acidifizierenden Einfluß der Thiophosphinylreste an. Die Methylierung mit Diazomethan führt hauptsächlich zu S-Methylestern der Imidothiophosphinsäuren.

Notes: Die aus Isatosäureanhydriden 1 und Natriumhydrogensulfid erhältlichen Natriumsalze der Thioanthranilsäure 3 liefern bei der Oxydation in Abhängigkeit vom Substituenten am Stickstoff 2.1-Benzisothiazisothiazolinone-(3) 4 oder Dianthranoyl-disulfide 5. Die 5 können unter speziellen Bedingungen zu 4 cyclisiert werden. Aus 4 sind mit Oxalychlorid 3-Chlor-2.1-benzisothiazoliumchloride 7 zugänglich, die mit Schwefelwasserstoff zu den Thionen 6 und mit Dimethyl-anilin zu den Polymethinen 9 reagieren. Die Farbstoffe 9 können auch aus den durch Alkylierung der 6 zugänglichen 3-Methylmercapto-2.1-benzisothiazoliumsalzen 8 dargestellt werden.

Notes: Es wird eine Zuordnung der 13C-Resonanzen der Paraffine der Roherdölfraktionen zu entsprechenden C-Atomen möglicher Strukturelemente vorgenommen. Daraus ergeben sich neue Informationen über die Struktur der Isoparaffine des Erdöls.

Notes: Sekundäre 2-Amino-äthylarsine, RAs(H)—CH2—CH2—NMR′, reagieren mit CS2 zu den 1.3-Azarsolidin-thionen. Unter geeigneten Bedingungen sind dabei auch die Ammoniumsalze der 2-Arsinoäthyl-dithiocarbamate als primäre Reaktionsprodukte isolierbar. Die 1.3-Azarsolidin-2-thione reagieren mit elektrophilen Agentien am Schwefelatom, wobei 2-Alkylthio- bzw. 2-Organostannylthioazarsoline sowie 1.3.-Azarsolidin-2-one zugänglich sind.

Notes: Einwirkung von Palladiumchlorid auf Acrylsäure-diallylamid 1 führt zu einem Gemisch von fünfgliedrigen Heterocyclen, wobei überwiegend Ringschluß zwischen der Acryloylgruppe und einer Allylgruppe erfolgt (Bildung von 2, 3, 4, 5 und 6), daneben Ringschluß zwischen den beiden Allylgruppen zu 7 und 8. Der letztere Fall überwiegt bei Rhodiumkatalyse (Bildung von 7); daneben entstehen geringe Mengen 4, 2 sowie ein weiteres Isomeres 14. Bei Anwendung größerer Rhodiummengen lassen sich N-ständige Allylgruppen von Säureamiden quantitativ abspalten.

Notes: Oxo-alkan-phosphonsäuredialkylester reagieren mit Diolen bzw. entsprechenden Schwefelanaloga zu Ketalen bzw. Thioketalen 1-19 der allgemeinen Formel Die aus verschieden substituierten Oxo-alkan-phosphonsäurediäthylestern 21 und aromatischen Diazoniumsalzen zugänglichen Arylhydrazone lassen sich ohne vorherige Isolierung zu den Indolyl-2-phosphonsäurediäthylestern 20 cyclisieren. Die 1-Aryliden-2-oxo-propan-phosphonsäureester 22 und 23 liefern mit β-Aminocrotonsäureäthylester im Sinne einer MICHAEL-Addition und anschließender Enaminbildung die Dihydropyridin-3-phosphonsäureester 24 und 25.Die IR-Daten der dargestellten Verbindungen werden mitgeteilt.

Notes: 3-Amino-1.2-dithioliumsalze 2a-1 sind in einfacher Weise aus 3-Chlor-1.2-dithioliumsalzen 1 und sekundären Aminen zugänglich.Es wird ein neues Verfahren zur Herstellung von 2-Nitro-3-amino-thiophenen 3 aus N,N-disubstituierten 3-Amino-5-phenyl-1.2-dithioliumsalzen 2 durch nucleophilen Austausch eines Schwefelatoms gegen das C-Atom des Nitromethans beschrieben. Die Struktur der Thiophene 3 wird durch reduktive Cyclisierung und spektroskopische Methoden gesichert.

Notes: Es werden Synthesewege für die bisher unbekannten 4-Arylazo-isoxazoliumsalze (z. B. 3, 4, 8, 14), einer neuen Klasse kationischer Farbstoffe, angegeben. 3 bzw. 4 sind durch Alkylierung der Isoxazole 5 bzw. durch Umsetzung von 1,3-Dicarbonylverbindungen des Typs 1 mit N-Alkylhydroxylaminen zugänglich. Im Gegensatz zum Isothiazolsystem kommt es bei den Isoxazolen 5 nach Alkylierung des Ringstickstoffes kaum zu einer Farbvertiefung.4-Arylazo-5-methoxy-isoxazoliumsalze (z. B. 8) sind durch Alkylierung der 4-Arylazo-isoxazolinone-(5) (6 bzw. 11) mit Dimethylsulfat darstellbar. Eine analoge Reaktion mit den 4-Arylazo-5-alkylmercapto-isoxazolen (z. B. 12, 13) gelingt nicht; die erwarteten 4-Arylazo-5-alkylmercapto-isoxazoliumsalze (z. B. 14) sind jedoch aus 12 und Triäthyloxoniumfluoborat synthetisierbar. Für 12, 13 und die 4-Arylazo-isoxazolinthione-(5) (9, 10) werden einfache präparative Vorschriften angegeben.

Notes: Der Zerfall der Bis-(halogen-triphenyl-antimonyl)-peroxide 1 a und b wurde hinsichtlich der Zersetzungsprodukte, der Kinetik und des Einflusses verschiedener Faktoren untersucht. Es wurde gefunden, daß bei der Zersetzung neben einer heterolytischen Spaltung der O-O-Bindung unter 1.2-Umlagerung bei dem bromhaltigen Peroxid 1 a leicht eine Abspaltung von Singulett-Sauerstoff erfolgt. Der Mechanismus dieser Reaktion wurde aufgeklärt.

Notes: Treatment of an equilibrium mixture of E- and Z-N-(2-alkylidene)anilines in CCl4 with paramagnetic shift reagents such as Eu(DPM)3 displayed a selective complexation with the Z-isomer of the ketimine.

Notes: Während bei der Umsetzung von 2-Aminoalkylarsinen des Typs RAs(H)-CH2CH2NH2 mit Ameisensäure oder Carbonsäurechloriden die entsprechenden Amide entstehen, sind durch Reaktion mit Iminoesterhydrochloriden 1.3-Azarsoline erhältlich. IR- und NMR-Daten werden angegeben.

Notes: α-Amino-α-(4-hydroxy-3,5-di-tert.-butyl-phenyl) - methanphosphonsäurediäthylester 1 lassen sich auf verschiedenen Wegen in (4-Hydroxy- 3,5-di-tert.-butyl-phenyl)-methan-bisphosphonsäuretetraäthylester 2 überführen. Ablauf und Intermediärprodukte dieser z. T. auffallend glatt verlaufenden Reaktion werden untersucht.

Notes: Es wird die Synthese von drei Analoga des Bradykinins beschrieben, in denen das Phenylalanin in Position 8 durch L-α-Amino-γ-phenylbuttersäure ersetzt ist. Zusätzlich wurde in Position 9 Arginin gegen Norarginin und Homoarginin ausgetauscht.

Notes: Es wird die Synthese von [5-Tyr, 6-Gly]-, [8-Tyr, 6-Gly]-, [5.8-Di-Tyr, 6-Gly]-Bradykinin und der C-terminalen Partialsequenzen beschrieben. Die Bradykininanaloga werden mit dem Dansylrest und einem Iminoxylradikal-Spinmarker substituiert.

Notes: Es wird die Synthese von drei Analoga des Nonapeptids Bradykinin mit C-Phenylglycin anstelle von Phenylalanin in Position 8 beschrieben. Zusätzlich wurde Arginin in Position 9 gegen Norarginin oder Homoarginin ausgetauscht.

Notes: Mit Hilfe gaschromatographischer Studien wird der Zusammenhang zwischen der Struktur von O-Silyl-β-dicarbonylverbindungen und ihrer Neigung zu Transsilylierungsreaktionen untersucht. Es wird gefunden, daß die Silyderivate von β-Diketonen und β-Dicarbonsäureestern Silylreste rasch untereinander austauschen und auf freie 1.3-Dicarbonylverbindungen übertragen, daß dagegen bei Silylderivaten von β-Ketosäureestern, o-Acylphenolen und Salicylsäureestern keine Transsilylierungen zu beobachten sind und Silygruppen-Übertragungen von O-Silyl-β-ketosäureestern auf freie β-Ketosäureester nur langsam ablaufen.Da die Neigung der O-Silyl-β-dicarbonylverbindungen zu Transsilylierungen in allen Fällen mit der Racemisierungsgeschwindigkeit optisch aktiver O-Silyl-Derivate strukturell gleicher β-Dicarbonylverbindungen korreliert, wird angenommen, daß intermolekular unter Umkehr der Konfiguration ablaufende Transsilylierungen die Ursache für die Racemisierung sind.Zusammenhänge zwischen der Neigung zu Transsilylierungen und dem ebenfalls strukturabhängigen sterischen Verlauf der Umsetzungen optisch aktiver O-Silyl-β-dicarbonylverbindungen mit LiAlH4 konnten dagegen nicht aufgefunden werden.

Notes: Für 8 homologe Cholesteryl-n-alkylcarbonate sowie das Cholesterylchlorid wurden die Hauptbrechungsindizes der cholesterinischen kristallin-flüssigen Modifikation in Abhängigkeit von der Temperatur und für verschiedene Wellenlängen gemessen. Die Messungen wurden an homogen orientierten Schichten nach dem Prinzip des ABBEschen Doppelprismas durchgeführt. Aus den Brechungsindizes der cholesterinischen Struktur können näherungsweise die Hauptbrechungsindizes der entsprechenden unverdrillten nematischen Struktur berechnet werden.

Notes: 1,10-Phenanthroline can be chlorinated directly with sulfuryl and thionyl chloride giving a chromatographically separable mixture of polychloro compounds.

Notes: Mittels Röntgenkristallstrukturanalyse wurde die Molekül- und Kristall-struktur sowie unter Ausnutzung der anomalen Streuung an den Chloratomen des Hydrochlorids von 2 die Absolutkonfiguration von (-)-Peganin 2 bestimmt. Danach besitzt 2 R-Konfiguration.

Notes: N-Alkyl-N-allyl-acrylamide 2 cyclisieren in Gegenwart von Palladiumchlorid zu 1-Alkyl-3.4-dimethyl-Δ3-pyrrolinonen-(2) 4 und 1-Alkyl-4-methyl-3-methylen-pyrrolidinonen-(2) 5, wobei der Typ 4 stark überwiegt. Durch Rhodiumchlorid erfolgt Ringschluß zu vergleichbaren Mengen an Lactamen 4 und 7 (1-Alkyl-3-methyl-4-methylen-pyrrolidinone-(2)); daneben wird Abspaltung des Allylrestes beobachtet. N. N-Diallyl-carbonsäureamide 3 geben mit Palladiumchlorid cyclische Enamide (1-Acyl-3.4-dimethyl-Δ2-pyrroline, 9) neben Produkten der Entallylierung. Rhodiumchlorid bewirkt Cyclisierung von 3 zu 1-Acyl-3-methyl-4-methylen-pyrrolidinen 11 neben wenig 9. In den Verbindungen 9 und 11 wird NMR-spektroskopisch das Vorliegen von rotationsisomeren Säureamidgruppierungen nachgewiesen.

Notes: α-Diphenylphosphinyl-phenylmethan-phosphonsäurediphenylester 1d reagiert mit aromatischen Aldehyden regiospezifisch unter Abspaltung der Phosphorylgruppe mit stark unterschiedlichen Ausbeuten zu α-Phosphinyl-stilben bzw. analogen Verbindungen 2. Dabei fallen in Abhängigkeit von der Größe des Restes R4 cis-trans-Gemische unterschiedlicher Zusammensetzung an. Bei kleinem Rest, wie z. B. Phenyl oder Pyridyl, entsteht fast ausschließlich das trans-Isomere, bei großem Rest, z.B. Chinolyl, steigt der cis-Anteil, bzw. das cis-Isomere wird zum Hauptprodukt. Die Selektion zwischen cis- oder trans-Konfiguration der Reaktionsprodukte wird bestimmt durch das unterschiedliche Ausmaß der sterischen Hinderung in den cyclischen Übergangszuständen. Die gleiche Reaktion mit 1b und Benzaldehyd ergibt kein P-substituiertes Stilben, sondern 1,2-Bis-(diphenylphosphinyl)-1,2-diphenyl-äthan 3, dessen Bildungsmechanismus diskutiert wird.

Notes: Die pKs-Werte von 49 Pyrazolon-(5)-Derivaten wurden durch potentiometrische Titration bestimmt und die 1H-NMR-Spektren der Substanzen in DMSO-d6 aufgenommen. Die experimentelle Aciditätssequenz befindet sich für strukturell ähnliche Verbindungen sowohl mit den Hammett-Konstanten als auch den HMO-Elektronendichten am Reaktionszentrum in guter Übereinstimmung.

Notes: Quantenchemische Störungsrechnungen auf MINDO/2-Basis für die thermische Homodimerisierung von Butadien, Isopren, trans- und cis-Piperylen unter Annahme eines einheitlichen cyclischen Modells für den Übergangszustand ergaben qualitative Übereinstimmung mit dem Experiment für die Verteilung der Cycloadditionsprodukte, die größere Reaktivität der substituentenfreien Doppelbindung und die Substitutionsverhältnisse der Sechsring-Addukte. Die gefundene Asymmetrie der Bindungsbildung stellt den konzertierten Ablauf der Cycloadditionsreaktionen jedoch nicht in Frage.

Notes: Von 23 theoretisch möglichen Chlorierungsprodukten des Isobutens mit bis zu drei Chloratomen wurden die Retentionsindizes nach Kovats an Flüssigphasen unterschiedlicher Polarität (Squalan, Phenyl-Methyl-Silikonöl, Nitrilsilikonöl, Polyäthylenglykol 4000) im Temperaturbereich von 90 bis 130°C gemessen. Der Einfluß von Position und Anzahl der Chloratome auf das Retentionsverhalten wird anhand der Retentionsindizes und der daraus abgeleiteten Homomorphiefaktoren Hs und Indexdifferenzen ΔI diskutiert. Es zeigt sich, daß polare und unpolare Wechselwirkungskräfte in unterschiedlicher Weise durch die Position der Chloratome im Molekül beeinflußt werden: Während z. B. zur Doppelbindung vinylständige Chloratome kleinere ΔI-Inkremente besitzen als allylständige, unterscheiden sich ihre Hs-Werte nur geringfügig. Für primäre Chloratome wurden signifikant größere Hs-Werte gefunden als für tertiäre Chloratome; dagegen sind ihre ∂ΔI-Werte nahezu gleich.

Notes: Für die Beschreibung der endo-exo-Produktverteilungen der Dien-Additionen des Cyclopentadiens mit Acrolein, Methacrolein, Crotonaldehyd, Butadien, Isopren bzw. Piperylen wurden EHT-Modellrechnungen am coplanaren endo-Orientierungs-Komplex zwischen Cyclopentadien und Acrolein vorgenommen. Bei nachträglicher Korrektur der EHT-Energien durch einen Madelung-Term wurden Abstandsvariationen im Bereich von 2,6-4,0 Å vorgenommen. Die endo-Orientierung erwies sich bei den betrachteten intermolekularen Abständen gegenüber der exo-Alternative als energetisch begünstigt. Auch die vom Dien zum Dienophil erfolgende Ladungsübertragung überwiegt im endo-Komplex zwischen Cyclopentadien und Acrolein. Eine Betrachtung der Bindungs-Wechselwirkungen im Rahmen einer Energieaufteilungsanalyse weist auf asynchrone σ-Bindungsbildung hin. Die cyclische Anordnung der Komponenten sollte dabei jedoch durch die stabilisierende sekundäre Wechselwirkung zwischen dem Carbonylkohlenstoff und dem nächstbenachbarten Zentrum des Diens erhalten bleiben, die im endo-Komplex gegenüber dem exo-Komplex über-wiegt. Daher erscheint die Formulierung eines „Ein-Schritt-Zwei-Phasen“-Mechanismus für diese Dien-Addition durchaus gerechtfertigt. Der Methylgruppeneinfluß auf das endo-exo-Produktverhältnis der Diels-Alder-Reaktionen des Cyclopentadiens mit Acrolein bzw. Butadien sowie der bevorzugte Angriff der methylsubstituentenfreien Diolefin-Doppelbindung werden im Rahmen ähnlicher Modelle weitgehend in Übereinstimmung mit kinetischen Resultaten, die teilweise von der Alder'schen „endo-Regel“ abweichen, beschrieben.

Notes: Die aus Pyrazolidon-(3) und Aldehyden leicht zugänglichen Azomethinimine 1 zerfallen bei der farbstoffsensibilisierten Photooxydation in Methanol als Solvens in Stickstoff, β-Methoxy-propionsäuremethylester 3 und Acrylsäuremethylester 4, wobei Abspaltung des Aldehyds 2 erfolgt. Es wird diskutiert, daß der gebildete Singulett-Sauerstoff (1Δg) als Dipolarophil mit dem 1,3-dipolaren System der Azomethinimine 1 zu einem cyclischen Peroxid 5 reagiert. Dessen Zerfall ist für die Produktbildung verantwortlich. Produkte der Photooxydation von 1 in Acetonitril sind Stickstoff, Kohlendioxid, Äthylen, β-Propiolacton 3 und Aldehyd 2.Die farbstoffsensibilisierte Photooxydation der aus Pyrazolidon-(3) und Ketonen gewonnenen Azomethinimine 16 im Solvens Methanol führt neben Stickstoff, β-Methoxypropionsäuremethylester 3, Acrylsäuremethylester 4 und dem entsprechenden Keton noch zu Hydrazin und den entsprechenden α-Methoxy-alkylhydroperoxiden 1 und 21. Die Peroxidbildung verläuft über ein Criegeesches Zwitterion der Ozonierung, das mit Acetaldehyd und Ozonid abgefangen werden konnte.

Notes: Bei der farbstoffsensibilisierten Photooxydation der heteroaromatischen N-Ylide 3a bzw. 3b wurden als Folgeprodukte der aus Singulett-Sauerstoff (1Δg) und den Yliden gebildeten 5-Ring-Peroxide Isochinolon-(1) 8 und Mesoxalsäurediäthylester 13 bzw. der Di-[benzoyl-oxoisochinolyl-(2)-methyl]-äther 10 erhalten. Ein Mol der Ylide 3c, 4 und 5 reagierte bei vollständigem Umsatz mit 0,5 Mol Sauerstoff zu den entsprechenden Heteroaromaten und den entsprechenden Mesoxalsäurederivaten 13 bzw. 15. Die Produktbildung und der Sauerstoffverbrauch wird durch Reaktion eines Moleküls Ylid mit einem primär gebildeten Hydroperoxid 18 erklärt.Die Ylide 3c, 4 und 5 reagieren mit Wasserstoffperoxid bzw. mit Perbenzoesäure gleichfalls unter Bildung der entsprechenden Heteroaromaten und der Mesoxalsäurederivate. Für die Umsetzung von Isochinolium-dicyanmethylid 3c mit substituierten Perbenzoesäuren ergab sich nach der HAMMETT-Beziehung ϱ = +0,94.

Notes: Orthosäurechloride reagieren mit Äthylenoxid je nach Struktur entweder zu Orthosäure-β-chloräthylester oder unter Abspaltung von 1,2-Dichloräthan zu den entsprechenden Carbonyl-bzw. Phosphorylderivaten. Auf diesem Weg sind unter anderem pentacovalente P-Verbindungen (Pentaoxyphosphorane 14, 16) zugänglich.

Notes: Die Geschwindigkeitskonstanten zweiter und dritter Ordnung der Reaktion von Bromcyan mit Phenolen in Gegenwart tertiärer aliphatischer Amine wurden in wasserfreiem Aceton bestimmt. Der erste Schritt der Reaktion besteht im nucleophilen Angriff des tertiären Amins an das Bromcyan. Es bildet sich durch eine schnelle Gleichgewichtsreaktion ein N-Cyano-N,N,N-trialkylammoniumbromid, das im langsamsten Schritt der Reaktion einen nucleophilen Angriff des Phenols oder eine Dissoziation erleidet. Die Bevorzugung einer dieser Reaktionen wird von der Nucleophilie und der sterischen Hinderung des tertiären Amins sowie von der Nucleophilie des Phenols bestimmt.

Notes: Die Darstellung der 2,6-Diallyloxy-4-alkyl(aryl)-1,3,5-triazine 2a - d wird beschrieben. Mit Nitriloxiden und Nitriliminen ergeben sie Cycloaddukte des Typs 3a - h und 4a - g.

Notes: Es werden Redoxpotentiale und pK-Werte von tetravalenten, unsymmetrisch verbrückten Dichinonen, Chinhydronen und Hydrochinonen beschrieben und Substituenten-einflüsse auf diese Eigenschaften diskutiert.

Notes: Der Einfluß der Größe des π-Systems, der Topologie, der cis-trans-Isomerie und der Substitution von Donatoren in π,π-Molekülkomplexen wird am Beispiel der TCNE-Komplexe von 6 phenylsubstituierten Äthylenen und von 9 substituierten trans-Stilbenen untersucht. Dazu werden die experimentell ermittelten ct-Anregungsenergien mit Hilfe störungstheoretischer Überlegungen diskutiert und mit den Ergebnissen von PPP-Berechnungen der Ionisierungspotentiale der Donatoren verglichen. Die untersuchten Donatoren sind entsprechend der Zahl, Stellung und elektronischen Wirkung von Substituenten in Gruppen klassifizierbar, deren Vertreter sich durch Analogien in den ct-Spektren auszeichnen.

Notes: Es wurde die Produktverteilung der Homodimeren von Isopren, trans-Piperylen und cis-Piperylen in Abhängigkeit von der Reaktionstemperatur in Toluol als Lösungsmittel bestimmt, und durch Extrapolation auf den Umsatz null wurden die durch Konkurrenzreaktionen entstehenden Produkte ermittelt. Aus den erhaltenen Meßdaten wurden die Geschwindigkeitskonstanten und die Aktivierungsparameter für die Bildung der bei der thermischen Homodimerisierung des trans-Piperylens ausschließlich entstehenden Sechsringdimeren sowie für die aus Isopren gebildeten Vier-, Sechs- und Achtringprodukte berechnet.Wie bei analogen Untersuchungen des Butadiens bereits festgestellt wurde [3], liegen die Aktivierungsparameter der symmetrieerlaubten Sechsringbildung und der symmetrieverbotenen Bildung von Vier- u. Achtringdimeren auch bei der Homodimerisierung des Isoprens sehr nahe beieinander.

Notes: Inspection of the polarographic behaviour of the phenylhydrazones of a variety of heterocyclic azoles having an adjacent functional group indicated that these compounds, unlike typical phenylhydrazones, are reducible in a 4-electron wave in both acidic as well as in alkaline media. A mechanism to explain the electrode processes is proposed.

Notes: Die Molrefraktion und die elektronische Polarisierbarkeit von einfachen Cyaninen und Merocyaninen werden experimentell in Abhängigkeit von der Polymethinkettenlänge in verschiedenen Lösungsmitteln bestimmt. In Bezug auf gleiche Molekülgröße besitzen die Cyanine die höchste Polarisierbarkeit aller bisher bekannten, ungesättigten organischen Verbindungen. Die elektronische Polarisierbarkeit der Merocyanine ist stark lösungsmittelabhängig. In unpolaren Lösungsmitteln nähert sie sich Werten, die bei Polyenen vergleichbarer Molekülgröße auftreten. In polaren Lösungsmitteln wird die hohe Polarisierbarkeit idealer Polymethine nahezu erreicht.

Notes: Substituierte γ-Halogen-α-cyancrotonsäurenitrile 1 reagieren mit primären Aminen sowie mit Ammoniak zu substituierten 2-Amino-3-cyanpyrrolen. Arylamine liefern dabei 1-Arylpyrrole, während mit Alkylaminen 2-Alkylaminopyrrole entstehen. Die Pyrrolbildung aus dem γ-Bromnitril 1b und Ammoniak bzw. Hydrazin ist mit einer Umlagerung verbunden. α-Chlorcyclohexylidenmalonitril 1c reagiert mit Hydrazin zum substituierten Dihydropyridazin 11, aus dem durch thermische Blausäure-Eliminierung das 3-Aminopyridazin 12 entsteht.

Notes: Zweikernaromat-bis(chrom-tricarbonyl)-Komplexe wurden durch direkten Umsatz des Zweikernaromaten mit Chrom-hexacarbonyl oder über eine Aromat-Verdrängungsreaktion mit Terephthalsäuredimethylester-chrom-tricarbonyl dargestellt. IR- und UV-spektroskopische Untersuchungen zeigen, daß beide Chromtricarbonyl-Reste praktisch voneinander unabhängige Struktureinheiten sind. Dagegen treten beim massenspektrometrischen und auch photolytischen Zerfall deutlich Unterschiede zum Verhalten der Einkernkomplexe auf.Nach UV-Bestrahlung der Komplexe in Tetrahydrofuranlösung in Gegenwart von Acrylnitril konnten Acrylnitrilverbindungen nachgewiesen, aber wegen ihrer Unbeständigkeit nicht in reiner Form isoliert werden. Unter hydrierenden Bedingungen im Autoklaven wirken die dargestellten Komplexe gegenüber Acrylnitril teilweise als Hydrierkatalysatoren, aber in keinem Fall als Dimerisierungskatalysatoren.

Notes: The Assignment of the 13C-N.M.R. Spectrum of 2,2,4-Trimethyl-2,3-dihydro-1H-benzo[b][1,4]diazepine

Notes: Sarcoplasmic reticulum (SR) of fast extensor digitorum longus (EDL) and slow soleus (SOL) muscles of the mouse was examined by freeze-fracture techniques. A distinctive feature of sarcoplasmic reticulum from the EDL is the presence of hillocks on the A-face within the terminal cisterns. These hillocks are usually arranged in a single row which is deployed parallel to the long axis of the adjacent T-tubule. Center-to-center spacing of hillocks within a row is about 70-75 nm. Hillocks are also found scattered within the collar region. The EDL of ten week mice was characterized by sheet-like terminal and intermediate cisterns, the latter being replaced in 37 week animals by thin tubular longitudinal elements of the SR which contain no hillocks or dimples.Hillocks occur only occasionally in SR from 10 or 20 week SOL muscle. In such cases the hillocks occur singly rather than in rows as in the terminal cisterns of EDL. The predominant form of SR in the SOL contains no hillocks.Total particles in the A-face of EDL-SR (2996 particles/μ2; S.D. = ± 287) slightly exceeded that of SOL-SR (2558 particles/μ2; S.D. = ± 274 8 nm). Packing density of 8 nm particles was slightly higher for EDL (750/μ2) vs. SOL (700/μ2). The possible significance of these features of SR in fast and slow muscle is discussed.

Notes: The yolk sac placenta has been implicated previously in transmission of passive immunity to the fetus. This work uses an immunohistochemical technique devised by Sternberger et al. (1969) to study this problem. Rabbit serum containing gamma globulins was injected into the uterine lumen of the White Swiss mouse during the last third of pregnancy. Two or four hours later yolk sacs were removed and fixed in 2% paraformaldehyde or freeze-dried and fixed with paraformaldehyde vapors. Finely chopped tissue was treated with (1) sheep antiserum to rabbit gamma globulin, (2) an antigen-antibody complex consisting of horseradish peroxidase and rabbit anti-horseradish peroxidase and (3) hydrogen peroxide and 3,3′-diaminobenzidine. Reaction product was heavily concentrated in visceral yolk sac endodermal cells, frequently deposited in endothelial cells of vitelline vessels, and rarely in the serosal basement membrane and mesothelial cells which border the exocoelomic cavity. This supports evidence of other workers that the yolk sac membrane rapidly absorbs substances with which it comes in contact, transport into vitelline vasculature is a route of transfer from mother to fetus, and possible transfer into the exocoelomic cavity and thence to the amniotic cavity may occur in mice.

Notes: Human aorta was prepared for scanning electron microscopy using critical point drying. The aortic surface is lined by a continuous layer of squamous endothelial cells. The luminal surface of these cells contains many microvilli or microappendages and pinocytotic vesicles. In addition, at the periphery of each cell, larger marginal appendages or microfolds are present which allow the observer to see the cell boundaries clearly. The marginal folds are superficial to the cell junctions and could be observed without any staining procedures. These observations on human aorta are generally in agreement with our findings on the rabbit and guinea pig aorta and vena cava but are in contrast to others who have reported the presence of ridges, intercellular bridges, and “hair-like” processes on the endothelial surfaces.

Notes: Microridges (MR), also called microvillar ridges, microplicae and cytoplasmic folds, have been noted on many epithelial surfaces. Several functions have been proposed for these structures. In the present study we examine the mechanical role that microridges may play in holding mucus to the lumenal surface of the esophagus in the trout Salmo gairdneri. Our findings support the hypothesis that the microridges help hold a protective coat of mucus to the epithelium. In addition, the complex curved or whorled arrangement of microridges appears to facilitate the spread of mucus away from goblet cells.

Notes: The objective was to determine the distribution of growth hormone-release-inhibiting hormone (somatostatin) in the rat brain using the peroxidase-antiperoxidase immunocytochemical method with antisera prepared against unconjugated, synthetic somatostatin. Somatostatin occurred in low quantity in the organum vasculosum of the lamina terminalis. It was present throughout the full length of the median eminence and occupied the entire width between the tuberoinfundibular sulci. Most somatostatin was located in the dorsal portion of the external lamina, and the amount varied according to the mediolateral position. The bodies labeled for somatostatin were most often granules; occasionally they appeared as clusters of granules that seemed to be membrane-enclosed. Some of these bodies appeared to be portions of axons. Many of the larger bodies were arranged alongside tanycytes, but no label was distributed generally in tanycyte cytoplasm. Somatostatin was highly concentrated in the proximal one-quarter of the infundibular stem and appeared in lower concentration throughout the distal portion of the stem. It was absent from the pars nervosa and pars intermedia of the pituitary gland. The distribution of somatostatin in the median eminence differed considerably from that of gonadotropinreleasing hormone.Somatostatin was identified in the ventromedial and/or dorsomedial hypothalamic nuclei of only two animals. Here it was probably located in axons that terminated on neuronal cell bodies but also may have been present in a restricted portion of the perikaryonal cytoplasm.

Notes: The fine morphological and cytochemical (acid phosphatase) changes occurring during holocrine cell lysis in the sebaceous preputial gland of the adult rat were investigated. When cells reach full differentiation cisternae of the widespread rough endoplasmic reticulum show invaginations of the wall. Cytoplasmi areas comprising such altered cisternae, normal RER and some mitochondria, are later sequestered into autophagic vacuoles, either surrounded by a single membrane (type I-bodies), or by a thick wall formed by concentric membranes (type II-bodies). Other vacuoles with similarly stratified wall and containing debris and acid phosphatase appear in cells at the next stage of involution. These autophagic vacuoles (type III-bodies) are probably derived from type II-bodies, and become gradually transformed into residual bodies rich in myelin figures, while the cell membrane and the nuclear envelope rupture. These findings show that prior to cell disintegration most of the cell cytoplasm, with the exception of the lipid and proteinaceous secretion granules and some mitochondria, is focally degraded within autophagic bodies.

Notes: Using a combination of single isotope and double isotope autoradiography after injection of 3H-thymidine and of 3H- + 14C-thymidine, respectively, the cell cycle of normal and injured lens epithelial cells in the mouse was determined. Progenitor cells in the peripheral region of normal lens epithelium were found to traverse the replicative cycle in the same amount of time as the injury-stimulated cells in both peripheral and central (wound) regions. The individual phases were also the same length, except for a slight shortening of G2 in the injured epithelium. The durations of the phases were: S: 11-12 hours; G2: 1.5-2 hours; M: 4.2-5 hours; G1 (derived): 38-44 hours; and total cycle: 55-61 hours. Two findings were significant in view of previous observations that injury to mouse lens seldom induces lens opacity. First, while the cell cycle duration was not affected by injury, a burst of proliferation of potentially active cells ensued. And, secondly, this burst of proliferation involved only one cell cycle. Only a small number of cells, equivalent to the normal progenitor compartment, continued into a second replicative cycle. The wound was healed, therefore, mainly by one division cycle involving a large number of cells.

Notes: Besides the well-known striated muscle fibers, the cremaster muscle of the guinea-pig contains smooth muscle fibers, which appear either as isolated elements or as networks. These smooth muscle fibers are embedded within a matrix of the compact fibrous coat of collagenous connective tissue which covers the vaginal surface of the striated muscle layer. Presumably the smooth muscle fibers maintain the initial, fast contraction produced by the striated muscle fibers, thus attaining an economical, tonic elevation of the testicle.

Notes: Monosodium glutamate was administered daily on days 5 through 10 postnatally at a dose of 2.5 mg/gm body weight. Counts of remaining perikarya in the arcuate nucleus of adult mice indicated approximately an 80% decrease in the number of perikarya. The arcuate lesion resulted in endocrine deficits; reproductive capacity was reduced, animals were smaller in stature and obese, and the weights of the anterior pituitary, ovaries and testes were significantly decreased while adrenals were unaffected. Light microscopic studies revealed no significant changes in thickness or general histological appearance of the median eminence. At the electron microscope level, there were no alterations in the number of nerve terminals or dense core vesicles per unit area in the contact zone. These observations suggest that afferents to the median eminence from the arcuate nucleus may form a relatively small portion of its total nerve terminal population.

Notes: The growth of the basal unit of the mandible was studied by plotting the position, relative to the median plane, of the oval, mandibular and mental foramina in immature and adult skulls of Man, chimpanzee and gorilla. In Man, the basal unit was found to grow out along a constant logarithmic spiral. In the apes, the basal unit grew along a progressively unfolding logarithmic spiral, the amount of unfolding being greater in the gorilla than in the chimpanzee. It is argued that the mode of growth seen in the apes evolved, as these forms became more prognathous, because it requires less compensatory rotation of the mandible, while the mode seen in Man is probably closer to that which occurred in the common ancestral form.

Notes: In most marsupials, placentation involves only the yolk sac; however, in the bandicoot family, Peramelidae, a functional chorioallantoic placentation develops in addition (Hill, 1895, 1897, 1900; Flynn, ′22, ′23). This duality is viewed as having evolutionary significance because most eutheria have both placentae. Furthermore, the bandicoot trophoblast was reported to vanish from the chorioallantoic site in late gestation (Hill, 1897; Flynn, ′23); whereas, the eutherian trophoblast is identifiable throughout later pregnancy and may act as an immunological barrier between maternal and fetal genotypes (Kirby, ′68). Thus we have re-examined this singular chorioallantoic placenta of the bandicoot in plastic sections with light and electron microscopy.A distinctive feature of bandicoot placentation is the transformation of the uterine simple columnar luminal epithelium into a highly vascular lining composed almost entirely of discrete syncytial masses (homokaryons). Endometrial blood vessels penetrate among the homokaryons to create a rich network of large diameter capillaries at extremely superficial locations near the maternal surface.In the chorioallantoic placenta (7 mm to 10-11 mm crown-rump embryos) the microvillous surface of the maternal homokaryons interdigitates with the microvillous border of the fetal trophoblast with desmosomal interaction. This trophoblast consists of a single layer of tall columnar undifferentiated cells rich in ribosomes-polysomes, poor in cytoplasmic membranes, and with large nuclei that have distinct clumps of heterochromatin and conspicuous nucleoli. It is thus remarkable that these undifferentiated cells disappear as a recognizable layer later in gestation (12 mm crown-rump embryos).Flynn's hypothesis that the trophoblastic cells disapppear by fusing with maternal syncytia gains support from the existence of two populations of nuclei in the syncytial masses only at the chorioallantoic site. One population is comparable to that occurring in the homokaryons of the yolk sac placenta, i.e., pale staining nuclei with little heterochromatin and small peripheral nucleoli. However, the other nuclei resemble those of the trophoblast cells. Since the trophoblastic cells before their disappearance as a layer possess properties associated with potential for further differentiation, the possibility of fusion between the maternal homokaryons and the fetal trophoblastic cells to form heterokaryons composed of two genotypes merits further consideration.The disappearance of the trophoblastic layer and the superficial positioning of the maternal capillaries bring the maternal and fetal bloodstreams into closest proximity near term (12 mm crown-rump embryo). The thinnest parts of the barrier consist of delicate cytoplasmic extensions from the syncytial masses (that may be maternal in origin or jointly maternal and fetal) and a layer of maternal stroma intervening between the maternal and fetal endothelia. Thus the chorioallantoic placental barrier of the marsupial bandicoot is unlike any thus far described for eutherian mammals.

Notes: Microfilaments at the junctional specializations between adjacent Sertoli cells and between the Sertoli cell and the late spermatid of the mouse and swine testes bind HMM and form arrowhead complexes with a periodicity of about 35 nm. The arrowhead formation is inhibited when the tissues are treated with HMM in the presence of ATP. These observations show that the microfilaments are actin-like in nature. The functional significance of these filaments in the Sertoli cell is discussed.

Notes: The morphological sequence of events occurring in the development of the lateral-line organ was investigated in the embryo of the newt, Triturus pyrrhogaster, by means of electron microscopy. Six stages of development have been defined for convenience of description. The primordium of the lateral-line organ migrating from the pre- and post-auditory placodes is segmented into a small cell mass accompanied by a few Schwann cells enveloping nerve fibers. In the clump of cells of the lateral-line primordium, three kinds of cells are already distinguished by different degrees of darkness, i.e., dark, light and slightly dark cells (stage I). Both clump and Schwann cells enter the epidermis together (stage II). The two groups of cells are separated by the inner layer of the epidermis (stage III). The organ-forming cells elongate and the inner layer of the epidermis separates the Schwann cells from the clump (stage IV). The apexes of the organ-forming cells are exposed out of the epidermis (stage V). The lateral-line organ is almost matured. The dark cells correspond to type II of the supporting cells, the light cells correspond to type I of the supporting cells and the slightly dark cells correspond to the receptor cells because of the existence of cilia and a cuticular plate. The afferent nerve endings are found on the basal surface of the receptor cell (stage VI).

Notes: The exfoliating epithelial surface of the ectocervix (pars vaginalis) and the vagina from normal mice was studied by scanning electron microscopy during the four main phases of the ovulatory cycle, and after estrogen administration. At proestrus, the epithelial surface usually presented cobblestonelike structures furnished with thin microvilli; at estrus, large, flat mosaics covered by long, convoluted microrugae; at metestrus, the presenting cellular surfaces were of intermediate size (i.e., between cobblestone and mosaics) having fragmented microrugae; and at diestrus, by mosaics or intermediate structures covered by microvilli. Estrogen administration to intact and oophorectomized animals resulted in flat mosaics and large numbers of loosely attached cells with rolled-up borders which permitted the observation of the basal surface of the cells. In those animals the apical aspect of the cells which lined the lumen showed convoluted microrugae with circular configuration, while the basal aspect of such cells had club-tipped microvilli. The findings were correlated with post-scanning histological examination in all animals.

Notes: Scanning electron microscopy (SEM) is a potent tool that is especially valuable in interpreting the three-dimensional relationships of cells within tissues. This type of information is obtainable from thin sections in transmission electron microscopy (TEM) only by reconstructions of serial sections. The arrangement of the interstitial cells of the testis in relation to the capillaries and lymphatic channels, in particular, is easier to visualize in SEM than in TEM. Cytoplasmic constituents, as well as cell surface modifications, are demonstrable by this technique. The presence of droplets, presumably lipid droplets, both within and on the Leydig cells and the lymphatic endothelial cells, is quite evident. Other cytoplasmic structures are also apparent. For example, the possible functional significance of “openings” that are seen by SEM on the septa that surround lipid droplets is discussed relative to the appearance of the same area as seen in thin sections or in freeze-fracture replicas. SEM should become a very useful method for studying cytological and morphological alterations that occur in testicular tissue that is subjected to physical or chemical manipulation.

Notes: Earlier work has suggested that terminal nerve fibers in the periphery of the dental pulp are linked to one another and to odontoblasts by gap junctions although positive identification of the junctions was lacking. In this study, the lanthanum hydroxide tracer technique has been used to demonstrate that the junctions in this area do have the characteristic features of gap junctions, a wide dark intermediate line in transverse section, stippling in oblique section and a globular arrangement of sub-units in tangential section. Other studies have shown these junctions to be of low electrical resistance although the functional importance of this characteristic in this situation has not been determined.

Notes: The bone marrow contains branching vascular sinuses lying in a fibroblastic stroma which supports hematopoiesis. This paper describes the stroma and vascular sinuses by scanning and transmission electron microscopy and in freeze-fracture etch replicas in normal rat femoral marrow and in rats made eosinophilic by larvae of trichinella spiralis.The stroma consists primarily of reticular cells which ensheath sinuses as adventitial cells and branch into the surrounding hematopoietic space. They form a spongework on which hematopoietic cells are arranged. Erythroblasts, clustered into islets, and megakaryocytes lie just outside sinuses. Granulocytes, until the metamyelocyte stage, lie in the midst of the hematopoietic cords. Lymphocytes, monocytes and likely stem cells, are clustered about arterial vessels. Macrophages occur throughout the marrow. Fat cells occur adventitial to vascular sinuses and appear to be reticular cells which accumulate fat.Processes of reticular cells closely envelope hematopoietic cells or protrude into them. Reticular cells contain rough ER and are likely fibroblastic. The argyrophilic reticular fibers of the marrow are, however, slender and scanty. Reticular cells are rich in filaments and they may contain many microtubules. They are not phagocytic and possess few lysosomes. The reticular cell cover of a vascular sinus is lifted away as maturing hematopoietic cells approach the sinus, preparatory to crossing the endothelium and entering the circulation. Maturing granulocytes often show microvilli on reaching the basal endothelial surface.The level of eosinophils in the marrow may increase from approximately four to more than 20% after injection of trichinella larvae. Close distinctive association of reticular cells and eosinophils are marked.Reticular cells provide a physical spongework on which hematopoietic cells are supported. But I postulate that they also trap and induce differentiation of hematopoietic stem cells, and sort the differentiating hematopoietic cells into characteristic locations in their spongework.

Notes: The principal cell types associated with the humoral immune response (monocyte-macrophages, lymphocytes, and plasma cells) are numerous in the endometrial stroma of the uterus during the first four postpartum days in two types of mammals, the marsupial North American opossum and the eutherian albino rat. This transient cellular differentiation coincides with the physiologic period of rapid uterine regression which includes massive reduction in the amount of extracellular stromal material. In addition, heterophils and eosinophils, cell types also known to be associated with phagocytic and immunologic activity, appear in the stroma during the first two postpartum days; their presence may, however, be associated more directly with the postpartum estrus that occurs on day 1 postpartum than with endometrial regression. Thus, the five cell types, which are known in pathologic conditions to be components of an inflammatory response to a foreign antigen, are conspicuously present in the normal regressing endometrium. Furthermore, there is ample ultrastructural evidence of frequent macrophagic-lymphocytic interaction, transformation of lymphocytes, and active secretion by plasma cells during this early postpartum period.An hypothesis has been derived by uniting this new description of endometrial stromal cell differentiation with the existing literature on uterine collagenase activity, an important feature of postpartum regression (reviews by Gross, 1974; Harris and Krane, 1974). It is based on the assumption that during regression the extracellular action of neutral collagenase (and possibly other extracellular proteases) release new antigenic sites in proteins located in the ground substance. In the case of collagenase, these transient antigenic sites would arise at the locus of enzymic cleavage as well as from the subsequent denaturation of the fragments of the collagen molecule. This endogenous antigenic stimulus would be strong and temporary, and would lead to the cellular manifestations of the transient humoral immunologic response which are evident in the regressing stroma of these two mammals. This humoral immune reaction may be one of the regulatory mechanisms involved in the cyclic renewal of the extracellular compartment of the uterine stroma.

Notes: The parotid gland of the olive baboon, Papio anubis, was examined by electron microscopy. The acini are all serous in nature, and consist of pyramidal cells with abundant secretory granules of varying size. These granules consist of a dense matrix in which a denser spherule or lenticular body is present. Granules linked by a short isthmus are observed in the apical cytoplasm, and granules in the process of discharging their contents to the acinar lumen may be connected to the luminal plasma membrane by a neck-like protrusion. Intercalated duct cells contain granules reminiscent of those found in the rat submandibular acinar cells. The striated ducts consist of tall cells interloked in a complex fashion near their bases, with numerous vertically-oriented mitochondria lodged in their basal crenulations. Small vesicles whose contents vary in density are present in the apical cytoplasm as are large deposits of lipofuscin. The striated duct cells display a proclivity for ballooning into the duct lumen. Excretory ducts consist of simple to pseudostratified columnar epithelium, and lack basal striations or apical blebs.

Notes: In relation to chronological age and skeletal maturation, the growth of the second metacarpal is discussed based on radiographs of the right hand and wrist in 499 male and 424 female Japanese aged 1 to 18 years. When plotted against age, bone length and width present the general growth pattern of Scammon, the adolescent spurt occurring at about 13 years in the males and 11 years in the females, and the mean values are significantly larger in the males than in the females at age 15 years for length, and age 13 years for width, and later. The growth curves of both sexes are almost parallel to each other for bone length plotted against skeletal maturation. Bone width progresses in parallel in males and females until about adolescence, whereafter there is a more rapid increase in growth in the males than in the females. The mean values for length and width are almost always significantly greater in the males than in the females. The width/length index decreases rapidly until a certain period, the minimum value being at about ten years or a maturity corresponding to that age, and then increase slightly again to reach an equilibrium state on the basis of both age and skeletal maturation. At any given age, the mean values are always greater in the males than in the females. However, according to skeletal maturation, the sex differences are steadily significant at and after the skeletal maturity corresponding to about 12 years in the males and 10 years in the females.

Notes: Rat testes fixed by vascular perfusion were examined by scanning and transmission electron microscopy. This revealed a complex organization of the interstitial tissue and an extensive “testicular lymphatic space” composed of continuous “peritubular lymphatic sinusoids.” No cellular connections exist between the interstitium and the tubules. Each sinusoid completely surrounds an individual seminiferous tubule, and adjacent sinusoids communicate freely through fenestrae in the interstitium. Thus, material must enter the lymph to gain access to the tubules. The sinusoids are delimited by separate endothelial cell layers over the tubules and interstitium. The layer over the interstitium is discontinuous in specific areas according to the geometry of the tubule packing. Interstitial tissue located in the flattened biconcave interstices between two adjacent tubules is consistently covered with endothelial cells, while that located in the open, triangular interstices between three or more tubules consistently lacks an endothelium. Most of the Leydig cells are located in the “open interstitium” and are directly exposed to the lymph. Physiological implications of the “testicular lymphatic space” and additional features of the interstitium are discussed.

Notes: A circadian rhythm in the incorporation of tritiated thymidine into DNA of the mouse thymus has been described. This same rhythm in animals bearing an 8-day Ehrlich ascites tumor (EAT) was altered in its phasing, wave-form and over-all 24-hour mean; the most striking alteration seen in four out of five studies was a reduction in the over-all DNA synthesis rate in tumor-bearing animals.Mice subjected to an altered light-dark cycle did not show a complete phase shift in their thymus DNA rhythm within two weeks, but during this time the rhythm in the mitotic index of their corneal epithelium completely phase shifted; the presence of the tumor had no effect on this latter rhythm. In mice subjected to a daily 4-hour restricted feeding schedule, the rhythm in DNA synthesis in the thymus became synchronized in that the peak occurred toward the end of the 4-hour restricted feeding span in both tumor and non-tumor-bearing animals. The rhythm in the mitotic index in the cornea was not phase shifted or altered by the restricted meal timing.The DNA synthesis rhythm in the normal thymus demonstrated a phasing similar to (1) the rhythm in the length of survival time in untreated mice challenged with EAT and (2) the rhythm in DNA synthesis in the normal spleen.

Notes: The macroscopic anatomy of the brain of the American Plains Buffalo (Bison bison bison) is detailed herein for the first time. Many features vary significantly from most previously described ungulate species including its large size, fissural pattern of the cerebral hemispheres and well developed insular cortex. The midbrain, particularly the tectum, is outstanding: the superior colliculi appear to be the largest reported for any mammal and occupy most of the dorsal midbrain by surface area and volume estimates. The cerebellum is small relative to the total brain volume, a peculiarity reported elsewhere for other ungulates. Morphometric criteria further indicate the brain of bison is highly specialized. Drawing from various lines of evidence, it is suggested that the anatomical uniqueness of the present day bison brain may represent a vestige of the past, remaining largely unchanged over a broad expanse of geologic time.

Notes: In placentas from viable rat fetuses which surgically had been retained beyond term in lactating animals for as long as four days, the fine structue of much of the interhemal membrane was quite like that of full-term placentas. Moreover, contrary to what has been reported previously (Jollie, 1964a), in retained placentas which were autopsied at term there were few changes in the four cytoplasmic layers of the membrane which could be interpreted as degenerative. With prolongation of the placenta beyond normal delivery the number of pericytes which were associated with the allantoic endothelium increased; the basal lamina separating the endothelium from trophoblast III progressively became more focally split; and the apposed plasma membranes between this latter layer and trophoblast II appeared to dissociate. Trophoblast II became regionally divided in its cytoplasmic organization, its more superficial zone becoming highly infolded and/or vacuolar. As a consequence, the intertrophoblastic space between layers I and II became more extensive and complex. Within this space, a flocculent material appeared; and there was ultrastructural evidence of massive pinocytosis from the space by trophoblast II. With increased prolongation of gestation, a variety of lysosome-like inclusions appeared within this layer of the membrane.

Notes: The cat's tentorium cerebelli is an osseous structure which overlies much of the brain stem. None of the current brain atlases list the coordinates of this bony projection. With a stiff wire and a stereotaxic apparatus, the location of its free edge and dorsal surface was mapped in 1.0 mm steps in the skulls of 16 cats. In the midline the dorsal surface meets the calvaria at a point 7 mm posterior and 15 mm superior to the atlas zero (intra-aural plane + 10 mm horizontal). From this junction it slopes inferiorly and anteriorly between the cerebrum and cerebellum along a 50° slope to terminate along a curved line. In the midline this free edge is located 0.5 mm anterior, and 6.5 mm superior to the atlas zero. It recedes laterally along a curved line to a point 6 mm lateral, 6 mm superior and 3 mm posterior to the atlas zero. The free edge then curves forward and descends to pass through an imaginary line 3 mm anterior and 4.5 mm inferior to the atlas zero. Statistical comparisons between measurements made in male and female cats revealed no significant differences.

Notes: Quantitative microscopic techniques were employed to determine relative mitotic activity of lobulo-alveolar tissue in thick sections obtained from the inguinal mammary glands of colchicine-treated post-pubertal Lewis/Mai rats sacrificed at different phases of the estrous cycle. It was found that the magnitude of lobulo-alveolar cell mitotic activity and the proportion of the lobulo-alveolar tissue with mitotic activity undergo significant fluctuations during the estrous cycle. The frequency distribution of mitotic activity in lobulo-alveolar tissue was different and heterogenous at each phase of the estrous cycle. The frequency distribution of nuclei in lobulo-alveolar tissue during the estrous cycle showed only minor variations and could not explain the variation in mitotic activity. Similarly, no morphological differences were observed in the mammary gland which could account for the variation observed in mitotic activity.It was concluded that the variation in mitotic activity of lobulo-alveolar tissue is probably related to alterations in the generation time of lobulo-alveolar cells imposed by cyclical variation in ovarian hormones during the estrous cycle.

Notes: The ligamentous anatomy of the wrist was analyzed by studying (1) 28 dissected human wrists, (2) and by examination of 19 wrist injuries created mechanically. Six volar intracapsular ligaments are described, two stabilizing the distal carpal row, three stabilizing the proximal carpal row and one stabilizing the proximal scaphoid pole. More specific terminology for these ligaments is proposed. An explanation of how these ligaments participate in the mechanical functioning of the carpus is advanced. Mechanically created wrist injuries had ruptures of specific ligaments as described augmenting a need for a more specific terminology. Suspected mechanisms of injury in perilunate and lunate dislocations are mentioned based upon the functional understanding of the intracapsular ligaments.

Notes: The appearance and development of the primary and secondary sympathetic trunks in staged chick embryos was studied using the Falck-Owman histochemical method for the demonstration of primary monoamines. The earliest appearance of catecholamine (stage 20) was in individual fluorescent cells located in the region of the dorsal root ganglia about two stages prior to the formation of primary trunk aggregates. These cells are believed to be sympathetic precursor cells and correspond to formaldehyde-induced fluorescent cells observed in recent explantation experiments. Aggregates of fluorescent cells had formed bilaterally dorsolateral to the aorta at stage 22. These aggregates became continuous to form primary trunks by stage 24. The secondary sympathetic trunks were first seen in stage 25 and appeared to form at least partially by dorsal migration of cells from the primary trunks. Fluorescent cell processes were first observed at this stage. Secondary trunk formation was essentially complete by stage 28, and the primary trunks had become small and discontinuous. Definite rami communicantes could be observed by the early part of stage 28 in silver preparations. The significance of the development of two successive trunks in avians is discussed.

Notes: The process of erythropoiesis and vasculogenesis in the yolk sac of the bat (Tadarida brasiliensis cynocephala) has been studied through the use of both light and electron microscopy. Stem cells arise from the leading edge of the migrating splanchnic mesoderm and transform into primitive erythroblasts. Differentiation involves either contact or association with the endodermal cells, since all erythropoietic activity occurs on the endodermal side of the expanding vascular bed, and many of the cells are in close apposition to the lateral or basal plasma membranes of the endodermal cells. Endodermal cells also phagocytize developing primitive erythroblasts during the later stage of the process when erythropoiesis is subsiding in the yolk sac.Cells destined to become the endothelium of the expanding vascular bed also arise from the leading edge of the migrating splanchnic mesoderm. Their process of differentiation involves the development of cytoplasmic extensions that may surround a group of differentiating erythroblasts, enclosing them in the newly formed lumen of the blood vessel. The cytoplasmic extensions make contact and develop junctional complexes with similar processes from other cells to complete the lumen of the lengthening vascular bed.Cells of the granulocyte series or megakaryocytes are not observed in the yolk sac of the bat as has been described in certain other species.

Notes: During the annual breeding season, the testes of the lizard Cnemidophorus gularis are yellow-orange, ovoid organs measuring almost 1 cm in greatest diameter. The pigment is confined to the testicular tunic, which contains a zone of Leydig cells and vascular channels more than 50 m̈ thick. Leydig cells constitute approximately 60% of the zone, with remaining space occupied by capillaries, sinusoids, and lymphatic vessels. Lymphatics are concentrated at the interface between tunic and seminiferous tubules. Interstitial space is poorly developed among the tubules, accounting for less than 3% of tissue volume. Capillaries, lymphatics, and a few widely scattered Leydig cells occur in the sparse interstitial space. Leydig cells in the tunic and elsewhere in the testis show ultrastructural features commonly found in mammalian Leydig cells. Separation of the tunic from the seminiferous tubules is achieved in a few seconds by manual decapsulation of the testis and yields an enriched preparation of Leydig cells that is essentially uncontaminated by tubular elements.

Notes: The hamster accessory optic fiber system has been investigated with the use of de Olmos-Ingram and Fink-Heimer silver methods following the production of unilateral ocular enucleation. It was found that this fiber system consists of both crossed and uncrossed inferior and superior fasciculi. The fibers of the inferior fasciculus (anterior accessory optic tract) run along the medial edge of the cerebral peduncle and terminate within the medial terminal nucleus of the accessory optic system. The fibers of the superior fasciculus (posterior accessory optic tract) leave the main optic tract, pass superficially over the medial geniculate nucleus and the cerebral peduncle; they synapse within the dorsal, the lateral and the medial terminal accessory optic nuclei. The presence of a retinohypothalamic tract could not be confirmed.

Notes: During the first four days postpartum, heterophils (polymorphonuclear leucocytes) and macrophages occur in the intercellular compartment of the luminal epithelium of the uterine endometrium. Cytochemical and ultrastructural evidence indicates that transepithelial emigration of these stromal cells to the uterine cavity is occurring. This event takes place while the luminal epithelium is proliferating in response to the estrogenic stimulus of the postpartum estrus.Heterophil emigration precedes that of the macrophages and is most conspicuous during days 1 and 2. Although it has been established that collagen fibrils occur in uterine phagocytes (Schwarz and Güldner, 1967) assumed to be macrophages (Parakkal, 1969, 1972), their precise role in collagen degradation remains undefined. It seems likely that the emigrating macrophages, heavily laden with phagolysosomal derivatives and lipid droplets, are hauling the remnants of the intercellular substance out of the endometrium during days 2-4 postpartum. Ultrastructural evidence indicates that the emigrating macrophage punctures the basal lamina and passes through the intercellular compartment of the luminal epithelium by active penetration.Another mode of macrophagic egress operates in the deep stroma of the endometrium and myometrium where lymphatic drainage occurs. Macrophages accumulate in the perilymphatic stroma as well as within lymphatic vessels.Thus macrophagic emigration through the luminal epithelium and lymphatic vessels may provide a cellular mechanism for elimination of the intercellular stromal substance in the regressing uterus. Transepithelial emigration is a mechanism which operates also in the marsupial uterus (Padykula and Taylor, 1976), and thus may be a fundamental mechanism among subprimate mammals that fulfills in part the function that menstruation effects in primates.

Notes: Female rats were divided into six groups: (1) control, (2) one uterine artery (a.) ligated near the utero-tubal (U-T) junction, (3) one uterine a. ligated at the level of the cervix, (4) both uterine aa. ligated separately at the U-T junction, (5) both uterine aa. ligated separately at the cervix and (6) both uterine aa. tied with one ligature at the cervix. Segmental aa. were disrupted in all experimental groups except group 6. Animals were allowed to recover for ten days and killed the first metestrus thereafter. Number of eggs ovulated was determined by flushing the oviduct with saline solution and counting the ova.Control rats ovulated 5.0 ± 0.4 eggs per ovary. Groups 2 and 3 had an increase in the number of eggs shed from the ovary on the non-ligated side. In contrast, a decrease in the number of ova shed occurred on the ligated side. When both aa. were ligated separately (groups 4 and 5), irrespective of location, a decrease in the number of eggs shed by both ovaries was evident. No effect was found when only one ligature was placed near the cervix (group 6).The data demonstrate that blood supply to the ovary via the uterine artery is essential for the full complement of eggs to be shed.

Notes: Explanted blastoderms of freshly laid chicken eggs expand their area during the first 44-45 hours of incubation by a factor of at least 11 if they are placed with the epiblast on the inner surface of explanted fresh chick vitelline membrane and provided with chick egg extract. This expansion is due essentially to the spreading of the yolk sac-serosal membrane. On turkey and duck membrane the expansion factor is about 6 and 3.8 respectively under otherwise identical conditions, but 1.9 only on a semisolid nutrient agar plate. Only the inner surface of the vitelline membrane has this growth-promoting potential, which markedly and progressively declines during incubation in ovo because of systemic factors rather than because of a direct influence by the outgrowing yolk sac-serosal membrane. Trypsinization of fresh chick vitelline membrane (1% trypsin 3 hours) reduces the growth-promoting potential to about 40% of its normal strength. The outgrowth of the extraembryonic tissues on vitelline membrane is better supported in the presence of a species' own egg extract than by extract from another species.

Notes: This study covers the period from the fortieth day after ovulation to the thirty-eighth day after birth. In addition, lungs of two mature monkeys have been analyzed. Birth occurs about the one hundred sixty-eighth day (24 weeks after ovulation). By the fortieth day the patterns of the bronchopulmonary segments are well established. These are the tools of the investigator. The curve of growth for the first 60 days parallels that of the rhesus monkey but is steeper than the human curve. At 63 days (9 weeks) pairs of rosette-like clusters of epithelial buds (future alveolar ducts) have appeared on peripheral branches of the segmental bronchi and continue to grow in size until the twelfth week. Then they resemble the paired rosettes of human acini of the seventeenth postovulatory week (Boyden, ′74) and probably represent the primitive unit from which the human was derived. In both man and monkey, canalization of the rosettes starts at about the same relative time (the 17th and 12th week, respectively) and spreads centralwards from the rosettes along the bronchioles of each segmental bronchus. In man, canalization forms acini (alveolar ducts and respiratory bronchioles). In the monkey, due to the monopodial pattern of branching, it produces racemes of alveolar ducts, each raceme ending basally in a pseudorespiratory bronchiole (127th day). By the one hundred fortieth day, enough surfactant has been secreted to support a premature infant. At one hundred fifty days, 11 generations of bronchi, followed by 16 of pseudorespiratory bronchioles, are present in the medial basal segment, followed in turn by 19 generations of prealveolar ducts (the latter provided with delicate spiral muscles) each giving off alternate branches of alveolar ducts. After one hundred fifty days of gestation, generations of bronchi, pseudorespiratory bronchioles, prealveolar ducts and cartilages (15) remain virtually constant for at least 38 days after birth. By the adult stage the number of generations of pseudorespiratory bronchioles has been reduced to three and the prealveolar ducts increased (at the former's expense) to 27. This study is concluded with a comparison of the lungs of the newborn monkey with those of the human/neonate and puppy.

Notes: The relationship between developing spermatids and Sertoli cell junctional specializations was studied with the electron microscope during spermiogenesis and at spermiation. At stage I of the seminiferous cycle, the newly formed spermatids are found in apposition to junctional specializations at the lateral surfaces of the Sertoli cell. Visualization of the junctional site of this early stage appears to be dependent on orientation and plane of section. As differentiation proceeds, the spermatids elongate and come to lie within deep recesses of the Sertoli cell. At this time the junctional specialization is limited to the acrosomal portion of the spermatid. During the maturation phase, the spermatids, while maintaining the same relationship to the junctional specialization, approach the lumen. When stage VIII of the cycle is reached, the stage in which spermiation occurs, the spermatids are at the luminal surface. The relationship of the spermatid head to the junctional specializations is quite variable during this stage. Some spermatids are observed still attached to the Sertoli cell at the junctional site, while others are found completely or partially surrounded by Sertoli cytoplasm, but with no evidence of the normally interposed junctional specialization. Yet, in other instances, the spermatids are observed in a position slightly removed from the junctional site. Also evident are profiles of junctional specializations at a free surface of the Sertoli cell, there being no attached spermatid. In some instances the junctional specializations appeared in apposition to a residual body. In the case of the free surface profiles, the junctional specialization at times lined an empty cleft or crypt-like recess, giving the impression that the spermatid head had just been dislodged from the junctional contact site. The findings indicate that the spermatid is in contact with a junctional specialization from its initial appearance and remains so until spermiation is initiated. It is postulated that spermiation is initiated through a physiological change in the junctional specialization resulting in loss of adhesion and consequent release of the sperm head from its attachment site. A similar mechanism is proposed in relation to the inter-Sertoli junctional complex to account for the means by which the spermatocytes cross this barrier to reach the adluminal compartment of the seminiferous epithelium.

Notes: During the course of gestation, a large amount of iron is transferred rapidly and unidirectionally from mother to fetus across the placenta. It has been postulated that one of the first steps involved in placental iron transfer involves binding of the maternal transferrin-iron complex to the surface of the placenta and the subsequent removal of iron and release of transferrin back into the maternal circulation. To determine if transferrin is present on the surface of human placental villi, two different immunocytochemical methods have been used: (1) an unlabeled antibody, peroxidase-antiperoxidase (PAP) method utilizing rabbit antiserum to human transferrin, goat anti-rabbit IgG and rabbit peroxidase-antiperoxidase complex or; (2) a peroxidase-labeled antibody method utilizing goat antiserum to human transferrin and peroxidase-conjugated rabbit anti-goat IgG. The peroxidase was then localized by incubation in a diaminobenzidine-hydrogen peroxide medium. Examination of the tissue in the electron microscope revealed the reaction product deposited as discrete patches or particles on the microvillous surface of human syncytial trophoblast. Controls using non-immune serum or an antiserum adsorbed with purified human transferrin showed no reaction product on the surface. The results provide morphological confirmation for the presence of transferrin on the surface of human syncytial trophoblast lining the maternal blood spaces.

Notes: The effect of the monosodium glutamate (MSG) induced lesion of the arcuate nucleus on catecholamines in the arcuate nucleus and median eminence of the mouse hypothalamus was determined using the Falck-Hillarp histofluorescence technique. The number of fluorescent perikarya in the arcuate nucleus of treated animals was decreased approximately 60%; the fluorescence intensity of surviving neurons was notably reduced. These changes were accompanied by a reduction in the intensity of fluorescence in the median eminence. Pretreatment of control and MSG-lesioned animals with a monoamine oxidase inhibitor (pargyline) greatly increased fluorescence in the median eminence and arcuate nucleus of both groups. However, the number of fluorescing perikarya of the arcuate nucleus of the normal pargyline treated group far exceeded that of the pargyline MSG animals. It is concluded that neonatally administered MSG caused destruction of a large number of dopaminergic arcuate perikarya.

Notes: Young adult male rats were treated with daily injections of 10 mg of cyproterone acetate for periods up to 16 weeks. Samples of the ventral prostate and the seminal vesicle were studied with the light and electron microscopes. Alterations visible with the light microscope included decreases in cell size, cytoplasmic basophila, the size of the nucleolus, and the amount of luminal secretory material. Ultrastructural changes in the epithelium of both glands involved mainly the organelles that participate in the formation of secretions. Large declines were observed in the abundance of rough endoplasmic reticulum, size of the Golgi apparatus, and number of secretory vacuoles. Lipid droplets accumulated in the seminal vesicle epithelium, and lysosomes were numerous in both glands. Changes were first observed microscopically in the seminal vesicle after one week and in the prostate after two or three weeks. Maximal development of the alterations occurred after treatment for approximately eight weeks.

Notes: The neurothelium obtained from human biopsy specimens is a very thin cellular layer located between the dura mater and the arachnoidea. It is a pluri-stratified squamous layer which has some epithelial features (desmosomes and tonofilaments), and lacks connective tissue fibers in the extracellular spaces. Usually there is increased nuclear and cytoplasmic density and enlarged extracellular spaces from the deepest to the most superficial layer.Since neurothelium is fragile and easily torn apart, it probably occupies the position considered to be the subdural space.

Notes: The kinetics of lymphoid cells within the epithelium of the small gut has been studied in various thymus-deprived mice and in antigen-deprived mice by the use of 3H-thymidine injections and radioautography. In thymusdeprived mice  - including adult thymectomized, thymectomized and irradiated, neonatally thymectomized, and nude mice  - and in germ-free mice decreased numbers of intraepithelial lymphocytes (IL) were found. On the other hand, the radioautographic results indicated that the remaining IL populations included both newly formed and long-lived lymphoid cells in the same percentages as found in sham-operated controls and normal mice. It is concluded that although the presence of the thymus and the antigen content of the gut is of importance to the maintenance of the numbers of cells in the lymphoid populations of the intestinal wall, the basic kinetics of these cell populations are preserved in deprived mice.

Notes: This work is based on a study of 62 circles of Willis (circulus arteriosus cerebri) from patients dead from diverse causes. We have described the wide diversity of variations found to be present in the arterial vessels that form the circle, we presented the frequency of the different variations, and finally we discuss the possible ontogenic cause of these variations.