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  • Scalp hair  (3)
  • Inner ear microcirculation  (2)
  • Chlorpromazine  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Human scalp hair as evidence of individual dosage history of haloperidol: a possible linkage of haloperidol excretion into hair with hair pigment (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 120-125 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Scalp hair ; Haloperidol ; Segmental analysis ; Dosage history ; Melanin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report a method for determining haloperidol concentration in human scalp hair and discuss a possible linkage of haloperidol excretion into hair with the hair pigment melanin. First, an animal study was conducted to support the idea that hair contains amounts of haloperidol corresponding to the doses given and pigmented hair contains much more drug than does unpigmented hair. The haloperidol concentration was measured using a radioimmunoassay technique after hairs were dissolved in 2.5 N NaOH solution and the drug extracted. Pigmented and albino rats, whose hair from an area on the back had been removed beforehand by plucking, were administered either 1,3, or 10 mg of haloperidol (i.p.) per kg body weight every day for 3 weeks. At the end of the administration period hair which had newly grown on the denuded area was plucked and collected. In each of the two groups classified by hair color the drug levels in the hair correlated with the doses given; however, the concentrations in the hair from the albino rats were much lower than those in the hair from the pigmented rats (which was less than 8.5%). Second, black and white hair was collected from each of seven human subjects with grizzled hair, who were receiving or had been administered haloperidol at fixed daily doses for more than 1 month, and the concentration of haloperidol in each type of hair was measured. In the same subject the concentration in the white hair was found to be much lower than that in the black (less than 10%). In three subjects the dosage had been changed before the hair samplings, and segmental analysis of the distribution of haloperidol in the black hair revealed that the dosage history was imprinted along the length, assuming a hair growth rate of 1 cm/ month; the distribution of drug along the white hair less obviously corresponded to the dosage. Third, another keratinized tissue, nail, was collected together with hair samples from 20 patients and the haloperidol level in the nail was measured and compared with that in the hair. The concentration of haloperidol in nail is only about 3.4% of that in hair. Taken together these results suggest that the mechanism for excreting haloperidol into hair is closely linked with that for the hair pigment melanin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00493470
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  • 2
    Digitale Medien
    Digitale Medien
    Chlorpromazine in human scalp hair as an index of dosage history: comparison with simultaneously measured haloperidol (1993)
    Springer
    European journal of clinical pharmacology 44 (1993), S. 439-444 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Chlorpromazine ; Haloperidol ; scalp hair ; melanin ; dosage history
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The concentration of chlorpromazine (CPZ) in hair was measured to demonstrate its value as an index of individual dosage history and compliance. An animal study using pigmented rats was conducted to confirm the dose-dependent accumulation of CPZ in hair. The concentration of CPZ in hair, newly regrown on a denuded area of the back after the administration of CPZ for 3 weeks, was 4.6, 8.5 and 16.6 ng·mg−1 hair after daily doses of 1.25, 2.5 and 5 mg·kg−1·day−1, respectively, significantly correlated with the daily dose. The concentration of CPZ in black hairs collected from 23 Japanese patients, who had been taking CPZ in fixed daily doses (30–300 mg/day), ranged from 1.6 to 27.5 ng·mg−1, and was significantly correlated both with the daily dose and with the trough plasma concentration at steady state. Several strands of hair collected from each of 5 patients, whose doses of CPZ had been changed within several months before sampling, were cut into 1-cm pieces successively from the scalp end and the concentration of CPZ in each piece was measured. With the assumption of a hair growth rate of 1 cm per month, the individual history of CPZ doses in all patients could be deduced from the distribution of CPZ along the hair shaft. In 5 patients with grizzled hair the concentration of CPZ in white hairs was much lower (〈10%) than in black hairs, suggesting that the strong affinity of CPZ for hair melanin may explain the accumulation of CPZ in black hair. The concentration of co-administered haloperidol (HP) in plasma and hair was also measured in 11 out of 23 patients. The CPZ concentration in hair was much lower than that of HP (about 0.3 to 7.8%), whether the comparison was made on the basis of daily dose or plasma concentration. This finding is discussed in relation to the affinity of the compounds for their melanin and photochemical stability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315540
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  • 3
    Digitale Medien
    Digitale Medien
    Using ofloxacin as a time marker in hair analysis for monitoring the dosage history of haloperidol (1994)
    Springer
    European journal of clinical pharmacology 47 (1994), S. 195-202 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Ofloxacin ; Haloperidol ; Scalp hair ; time marker ; dosage history ; HPLC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract Hair samples were obtained 1–5 months after ingestion of the antimicrobial ofloxacin, which had been given for 1 or 3 days at the commencement of haloperidol administration, or when its dosage was reduced. The axial distribution of ofloxacin, haloperidol and its active metabolite, reduced haloperidol, was analysed in segments from single strands of hair. Ofloxacin was detected where the content of haloperidol and reduced haloperidol along the hair shaft showed a sharp change, corresponding to the change in dose. When we matched the time scale of the dosage history to the growth rate, which was estimated using ofloxacin as the time marker, the distribution of the haloperidol and reduced haloperidol precisely coincided with the rise and fall in the dose of haloperidol. These findings demonstrate that ofloxacin can serve as a time marker when drug distribution along the hair shaft is used to obtain the drug exposure history of an individual.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194972
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  • 4
    Digitale Medien
    Digitale Medien
    The measurement of ofloxacin in hair as an index of exposure (1991)
    Springer
    European journal of clinical pharmacology 40 (1991), S. 581-584 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Scalp hair ; ofloxacin ; dosage history ; hair growth rate ; index of exposure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Several strands of hair were collected from each of patients who had been taking ofloxacin against bacterial infections some time in the past. In 10 out of total 14 subjects studied the drug was detected only in the hair portions corresponding to the administration period with the assumption of the hair growth rate of about 1 cm/month. Even in a subject who had received 300 mg/day of ofloxacin only for two days the drug could be detected in the corresponding portion. In 3 subjects the drug was detected in some other portion(s) than the corresponding ones. This might be due to the uncertainty of having used the drug on the other occasion. Only in one subject the dosage history could not be deduced from the drug distribution along hair length. In 3 subjects, who had taken the drug within 1 month, hair samples were collected every month for 3 or 4 consecutive months. The front of drug appearance in hair was clearly shown to move outwards along hair shaft every month at a pace of 1–1.5 cm/month. These results suggest that ofloxacin is excreted into human scalp hair, captured there and moves outwards along the hair shaft at its own growth rate. This leads to the concept that the distribution of ofloxacin along hair length can be used for knowing the individual exposure or non-exposure to the drug, and even for knowing hair growth rate when the innoculation(s) of the drug is strictly supervised and recorded.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00279974
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  • 5
    Digitale Medien
    Digitale Medien
    Role of thromboxane A2 in a microcirculation disorder of the rat inner ear (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 342-344 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Hearing disorders ; Inner ear microcirculation ; Thromboxane A2 synthetase inhibitor ; Thromboxane A2 receptor antagonist disorder
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Since thromboxane (TX) A2 causes vasoconstriction and platelet aggregation, we evaluation the effect of a TXA2 receptor antagonist (vapiprost) and a TXAZ synthetase inhibitor (Y-20811) on a microcirculation disorder in the rat inner ear that was induced by a photochemical reaction between an intravenous injection of rose bengal (RB) and green light. A gradual decrease of the cochlear action potential (CAP) to an 8 kHz sound stimulus was measured with an electrocochleogram and occurred after the RB injection. The CAP then disappeared 5 min after the injection of RB. Both vapiprost and Y-20811 significantly prolonged the time required to complete suppression of the CAP as compared with saline as control. These findings indicate that TXAZ may play an important role in microcirculation disorders in the rat inner ear.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00188383
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  • 6
    Digitale Medien
    Digitale Medien
    A new model for photochemically induced thrombosis in the inner ear microcirculation and the use of hearing loss as a measure for microcirculatory disorders (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 248 (1990), S. 105-108 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Inner ear microcirculation ; Photochemically induced vascular thrombosis ; Rose bengal ; Hearing loss
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A new photochemical method was employed to cause disorders in the inner ear's microcirculation, using the rat as an animal model. Hearing loss was used as a measure for establishing the altered microcirculation. Under pentobarbital anesthesia, the middle ear was opened by a ventral approach. The lateral wall of the cochlea was then illuminated with a filtered xenon lamp (wavelength 540 nm) while rose bengal was infused intravenously. Photoactivated rose bengal produces oxygen radicals and oxygen singlets, which subsequently damage the vascular epithelium to cause the adhesion and aggregation of platelets in the small vessels. Disintegration of the inner ear hair cells at the irradiated site became evident 24 h after the illumination. These findings further suggest that the photochemical occlusion in the inner ear's microcirculation led to ischemic damage of the stria vascularis and the hair cells in the inner ear. When the action potential (AP) of the cochlea was measured with an electrocochleogram a gradual decrease occurred after the illumination. When acetylsalicylic acid was injected intravenously before treatment, the time required to completely suppress the AP was prolonged in a dose-dependent manner. Findings indicate that our method causes a photochemically induced occlusion in the inner ear's microcirculation and is therefore potentially useful for evaluating the various effects of drugs on the ear.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00240231
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