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Notes: Introduction: Burn depth, based on the hemodynamic alterations that occur following a thermal insult, can be assessed in a rapid, non-invasive, and nondestructive fashion using near infrared (NIR) spectroscopy. NIR has the capability to determine the difference between superficial and full thickness burn injuries. Methods: Sixteen burn patients admitted to an adult regional burn center were studied and evaluated with the NIR point and imaging devices. Non-burned skin adjacent to the burn site was used as the control. NIR measurements were compared between superficial (8 wounds), full thickness (8 wounds) burn wounds and control sites. Results: NIR was able to easily detect an increase in oxyhemoglobin (68.3%, p 〈 0.05), oxygen saturation (4.8%, p 〈 0.05%) and total hemoglobin (91.3%, p 〈 0.05) which typically occurs with superficial burn injuries. Full thickness injuries experienced a substantial drop in oxyhemoglobin (88.8%, p 〈 0.05), oxygen saturation (79.1%, p 〈 0.05) and total hemoglobin (77.5%, p 〈 0.05) in comparison to control sites. Conclusions: These results confirm that NIR spectroscopy can successfully distinguish between superficial and full thickness burn injuries. The second phase of this study will involve determining the depth of indeterminant burn wounds and this preliminary data will also be presented. Acknowledgement: National Research Council of Canada

Notes: Introduction:  This study examines the capacity of near infrared spectroscopy (NIR) to differentiate partial thickness burns.Methods:  Adult burn patients (n = 19) presenting within 72 hours of injury and body surface area 〈 20% were studied. An independent observer classified the burn injuries as either superficial (SPT, n = 5) or deep partial (DPT, n = 14) thickness. NIR data, oxygen saturation and total hemoglobin, were collected from the burn site and adjacent nonburned control site. NIR data for burn sites were compared to respective control sites to adjust for between subject variability. Skin biopsies for histologic analysis were performed at the time of surgery.Results:  NIR spectroscopy was able to detect a slight increase (3.65%, p 〈 0.05) in oxygen saturation with SPT burns when compared to control sites. In contrast, DPT burns displayed a drop in oxygen saturation (17.65%, p 〈 0.05) in comparison to the control site. An increase in total hemoglobin was observed for both the SPT (15.83%, p 〈 0.05) and DPT (5.07%, p 〈 0.05) injuries in comparison to control sites. SPT and DPT burns are discernible (p 〈 0.01) based on oxygen saturation values but not total hemoglobin (p 〉 0.4). Histologic and clinical correlation with the NIR spectroscopic data will be presented at the conference.Conclusions:  NIR spectroscopy can distinguish between superficial and deep partial thickness burn injuries in the first 3 days post burn injury.PSI grant

Notes: Summary. Intrapartum chemoprophylaxis with benzylpenicillin or erythromycin significantly reduced the rate of transmission of group B streptococci (GBS) from mothers colonized during pregnancy to their babies from 45% to 3% (P〈0.001). None of the babies born to women who were given prophylaxis was colonized with GBS in the first 24 h of life. Six weeks after leaving hospital, however, 23% of the babies in the antibiotic group had become colonized with GBS compared with 44% in the control group. GBS strains resistant and tolerant to both benzylpenicillin and erythromycin were found in this study. Intrapartum chemoprophylaxis breaks the cycle of GBS transmission at birth and may be useful in preventing early onset GBS disease, but is unlikely to affect late onset infections.

Notes: Summary. Twenty-eight per cent of women investigated during pregnancy were carriers of group B streptococci (GBS). The use of broth enrichment was the most significant factor in determining GBS carriage rates. GBS carriage decreased during pregnancy. Transmission of GBS from mother to baby was related to vaginal carriage but rectal carriage in pregnancy was the best predictor of maternal carriage at term. Rectal and vaginal swabs taken at 28 and 36 weeks correctly predicted 92% of intrapartum GBS carriage. Although accurate prediction of intrapartum GBS carriage is possible, mass screening for GBS in pregnancy is unlikely to be cost-effective in those countries with a low incidence of neonatal GBS sepsis.

Notes: Summary. The epidemiology of group B streptococci (GBS) was studied in an obstetric unit and the related special care baby unit (SCBU). In 1 year 53 (77%) of 69 babies who acquired GBS from their mothers were colonized within 24 h of birth, compared with only 9 (35%) of 38 who acquired GBS from non-maternal sources. While 38 (36%) of 107 GBS colonized babies in the obstetric unit derived the organism from a non-maternal source, the value for the SCBU was only 2 (9%) of 23. In babies rectal and umbilical swabs gave the highest GBS isolation rates. Phage-typing and serotyping suggested that colonized mother baby pairs, rather than staff, were the primary source of hospital acquired GBS. This mode of GBS acquisition did not result in long-term carriage once babies had left hospital. Nosocomial transmission can play an important part in GBS epidemiology, but can be minimized by attention to infection control procedures.

Notes: A remote indicatively coupled radio frequency plasma has been used to oxidize titanium thin films evaporated onto silicon substartes. The substrate was heated during oxidation to temperatures between 200 and 500 °C using a resistively heated furance. Titanium dioxide layers were formed of thicknesses from 53 to 150 nm. The crystal structure was shown to be rutile by x-ray diffraction for oxidation temperatures of 500 °C. These samples were also seen to have a thin interfacial silicon dioxide layer. Measurements on 1-mm Al dot capacitors showed the leakage current of a 53-nm film oxidized at 500 °C to be below 10−8 A at a 2-V bias. Good capacitance-voltage characteristics were observed for high oxidation temperatures, with a dielectric constant of between 15 and 22 for the TiO2/SiO2 layers. The refractive index of the layers was measured by ellipsometry to be 2.5–2.6. Plasma oxidation thus provides a low-temperature method of forming titanium dixoide thin films.

Notes: The sexual behaviour of 16, oestradiol-treated, ovariectomized common marmosets was recorded before and after bilateral microinfusions of ibotenic acid (n = 8) or isotonic saline (n = 8) into the hypothalamus. Ibotenic acid-induced neuronal degeneration occurred in 5 females, mainly affecting the anterior and dorsomedial hypothalamus. Marked decreases in proceptivity (tongue-flicking, staring and immobile displays) occurred after ibotenic acid lesions, whereas sexual receptivity (refusals and terminations of male partners' mounts) was unchanged. In 3 females where microinfusions of ibotenic acid were attempted but failed to produce lesions, sexual behaviour was unaffected and resembled that measured in saline-treated controls. These results provide the first evidence that selective lesions of neuronal cell bodies in the anteromedial hypothalamus disrupt proceptivity whilst sparing sexual receptivity in a primate species.

Notes: This study used a combination of Western blotting and immunocytochemistry to test whether signalling pathways independent of cyclic AMP have the potential to induce phospho-CREB (pCREB)-like immunoreactivity (-ir) in the oPT. Western blot analysis of extracts of primary cultures of oPT using an antiserum against CREB, revealed a major band of CREB-ir at 44 KDa. The intensity of this band did not vary systematically with treatment. In extracts from untreated cells, Western blot analysis revealed a major band of pCREB-ir at 42 KDa which was not sensitive to agonist treatment. Treatment of cells with forskolin (10−6 M) increased the intensity of a number of other pCREB-ir bands at between ca. 38 and 44 KDa. The band at 44 KDa probably represented native pCREB whilst the other bands induced by forskolin probably represented pCREB-like proteins. Melatonin (10−6 M) alone had no effect on pCREB-ir, but it did inhibit the effect of forskolin on the ca. 38 and 44 KDa pCREB-ir bands. Treatment with lamb serum (1%) consistently increased the intensity of the ca. 38 and 44 KDa pCREB-ir bands relative to control cells, as assessed by Western blot. However, Western blot analysis did not reveal a consistent effect of melatonin on the pCREB-ir response to serum. The effect of serum on pCREB-ir in oPT cells was characterized further by immunocytochemical analysis. In contrast to experiments utilizing Western blotting, untreated cells did not possess detectable pCREB-ir. In serum-starved oPT and oPD cultures, treatment with serum induced exclusively nuclear pCREB-ir. A large majority of oPT cells (≥90%) were sensitive to serum (1%), and serum caused a time- and dose-dependent increase of nuclear pCREB-ir. Melatonin attenuated the response to serum in the oPT. This inhibition of the response to serum was not apparent in the oPD, demonstrating that the effect of melatonin was specific for a tissue known to express melatonin receptors. In oPT cultures, physiological concentrations of melatonin (10−9 M) partially reversed (ca. 70%) the inductive effect of 0.1% serum on nuclear pCREB-ir. However, in contrast to studies applying forskolin, the induction of pCREB-ir by serum occurred in the absence of measurable changes in the concentration of cyclic AMP, indicating that components of serum are able to stimulate the phosphorylation of CREB in the oPT through mechanisms independent of cyclic AMP. Both adenosine and prostaglandin E2 (PGE2) also induced nuclear pCREB-ir in the absence of increased levels of cyclic AMP. These results demonstrate that transcriptional activities in the oPT which are under the control of CREB may be modulated by convergent cyclic AMP-dependent and cyclic AMP-independent pathways. Regulation of these pathways by melatonin and other factors present in serum may be an important control-point in the generation of seasonal neuroendocrine cycles.

Notes: The effect of melatonin upon the activation of the intracellular effector enzyme, cyclic AMP (cAMP)-dependent protein kinase (PKA), was investigated in primary cultures of ovine pars tuberalis cells. Incubation of these cells with forskolin caused a rapid and dose-dependent activation of PKA (ED50 10∼6M). When cells were incubated with forskolin and melatonin simultaneously, the activation of PKA by forskolin was dramatically inhibited. This inhibitory effect of melatonin was dose-dependent (ED50 10−10M). Furthermore, treatment with melatonin rapidly deactivated PKA in cells prestimulated with forskolin. When pars tuberalis cell extracts were incubated with 8N3-[32P]cAMP, an analogue of cAMP used for photoaffinity labelling of native PKA, specific binding was observed in three bands with Mr of 54, 52 and 48 kd, representing the regulatory subunits of PKA II (in phosphorylated and dephosphorylated forms) and PKA I, respectively. These results indicate that melatonin is a potent inhibitory regulator of cAMP-mediated signal transduction in the ovine pars tuberalis, and suggest that the cellular effects of melatonin in this tissue are mediated by the dephosphorylation of specific substrate proteins.