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Biomedical subjects

P H Proctor

Publications and source records attributed to P H Proctor.

15 recordsLinked to original sources
PubMed1999

Hair-raising. The latest news on male-pattern baldness.

The initiating event in balding seems to be an abnormal sensitivity to the male sex hormones. In addition, a multifactorial model is emerging in which hormones affect the hair follicle in a way that causes it to be perceived as a foreign body by the immune system, which then mounts an attack. Several new classes of agents have the potential to treat hair loss. More than 40 U.S. and several hundred foreign patents have been issued for hair-loss treatment agents. As is common in dermatology, no single agent works universally against hair loss, so the treatment process is often one of trial and error.

Adult↗
PubMed1986

Effect of dose schedule of vitamin E and hydroxethylruticide on intestinal toxicity induced by adriamycin.

CDF1 mice receiving Adriamycin, 12 mg/kg IP develop a toxic GI mucositis. The mean survival in CDF1 mice after Adriamycin injection was found to be 6.5 +/- 2.0 weeks and could be increased by alcohol or acetate Vitamin E pretreatment (with 2 g/kg qDx7d) to 22.06 +/- 12.3 weeks or by treatment with Venoruton after Adriamycin (qDx7 with 1.5 g/kg) to 23.7 +/- 12.7 weeks. Other schedules were ineffective or harmful. The ability of Venoruton to enhance survival when given after Adriamycin encouraged us to proceed to tumor bearing mice. The maximum survival with CDF1 mice bearing 5 X 10(6) L1210 cells was 1 +/- 0.2 week which could be increased to 2.17 +/- 0.8 weeks with optimal dose Adriamycin (10 mg/kg). Optimum survival with Venoruton and a single dose of Adriamycin was 2.45 +/- 0.91 weeks with Venoruton, 1.5 g, qd X 14, and 12 mg/kg Adriamycin. Treatment of L1210 bearing mice with Adriamycin, 10 mg/kg on days 1 and 8, yielded a survival of 2.23 +/- 0.7 weeks. An equitoxic regimen of Adriamycin, 11 mg/kg on days 1 and 9, plus Venoruton, 1.5 g, qd X 14, increased survival 30% to 3.08 +/- 2.9 weeks. Venoruton is a promising agent to increase the therapeutic index of Adriamycin.

Animals↗
PubMed1984

Free radicals and disease in man.

Free radicals and related activated electronic species are produced in biological systems in antimicrobial defense, through the action of the mixed function monooxygenases, by various oxidative enzymes such as xanthine oxidase, and by autooxidations mediated by such agents as heavy metals or quinones. While the evidence is circumstantial, excessive unconfined or inappropriate production of radical species in inflammation, the metabolism of exogenous chemicals, or through autooxidation probably plays a significant role in human disease.

Antioxidants↗
PubMed1982

Participation of active oxygen species in 6-hydroxydopamine toxicity to a human neuroblastoma cell line.

Catalase, superoxide dismutase, and dimethylsulfoxide were tested for their ability to prevent the cytotoxic effect of 6-hydroxydopamine (6-OHDA) on the human neuroblastoma line SY5Y. Viability was measured at two time points after 6-OHDA treatment: at 3 hr by means of amino acid incorporation and at 24 hr by trypan blue dye exclusion. Survival of cells treated concomitantly with catalase (50 microgram/ml) and 6-OHDA was at least 90 per cent that of untreated controls. Cells receiving 6-OHDA alone showed less than 30 per cent survival relative to untreated controls. Superoxide dismutase (50 microgram/ml) temporarily protected cells from a high concentration of 60-OHDA. Dimethylsulfoxide treatment increased survival from the control level 24 hr after treatment with 6-OHDA. Two other cell lines (A1B1 human glial cells and CHO fibroblasts) had intermediate and high resistance to the drug, respectively, compared to the low resistance of SY5Y cells. CHO and SY5Y cells had similar responses to 6-OHDA and to H2O2 when tested at twice the molarity of 6-OHDA. Specific activities of three enzymes known to detoxify H2O2 or H2O2-generated organic hydroperoxides (catalase, glutathione S-transferase, and glutathione peroxidase) were compared in the three cell lines. Catalase activity was 2.5 times as high as in A1B1 and CHO cells as in SY5Y cells when expressed as units/mg protein and 7 times as high in units/culture dish. Other enzyme activities showed no correlation to 6-OHDA resistance.

Catalase↗
PubMed1979

Reversible and irreversible changes in hydrogen ion titration curves of melanins.

Hydrogen ion titration curves obtained on melanins prepared and modified differently show recognizable differences. Melanin prepared with NaOH exhibits irreversible loss of functional groups in the base range once titrated acidic. Melanin prepared with NH4OH shows two main branches selected by incubation at an extreme pH for 24 h. Longer exposure reveals other curves but they disappear once a 24-h schedule of titration is resumed. The existence of two major pH branches appears consistent with the oxidation-reduction properties of melanins. These results demonstrate the ability to obtain a reproducible feature in the hydrogen ion titration curves. Thus it is finally possible to quantitate CO2 adsorbed to melanin in solution at basic pH.

Ammonia↗
PubMed1978

Amelioration of cis-platinum nephrotoxicity by orgotein (superoxide dismutase).

In rats, daily administration of subcutaneous dose of 2.5 mg/kg of orgotein, the pharmaceutical preparation of Zn-Cu superoxide dismutase, lowers the nephrotoxicity induced by a 5.0 mg/kg dose of the antitumor agent cis-platinum (cis-diaminedichloroplatinum II). The toxicity of cis-platinum was studied by comparative measurements of blood urea nitrogen and changes in body weight, and by comparative renal histology. In addition to their direct clinical applicability, these results support a role for pathologic levels of oxygen radicals in the etiology of the nephrotoxicity of cis-platinum.

Animals↗
PubMed1976

A controlled trial of multiphasic screening.

A clinical controlled trial was designed to determine the impact of Automated Multiphasic Health Testing on morbidity and attitudes. Three strata comprising 574 families (lower-income group enrolled in health maintenance organization, lower-income not enrolled in such a project, and a middle-income group employed by a utility company) were interviewed to obtain information on utilization, morbidity, health status, and attitudes. Sixty percent of adults in each stratum were then screened. All families were interviewed again one year later. The only significant difference found between screened and non-screened subjects was an increase in nights hospitalized for screened subjects. Physicians were interviewed to determine what abnormalities were found and what treatment was required for project and privately referred patients of these physicians. Previously unknown abnormalities prompted retesting for confirmation in only 28 per cent of the cases and even less often led to treatment.

Adolescent↗
PubMed1975

Mail-order medicine; An analysis of the Sears Roebuck Foundation's Community Medical Assistance Program.

Of the 625 rural communities that originally applied to the Sears Roebuck Foundation's Community Medical Assistance Program, 253 were accepted. One hundred sixty-three went on to build clinics, and 132 had physicians at the time of follow-up. From the standpoint of physician coverage of the community once a clinic had been built, the rate of physician availability was 78 percent, The communities' success in recruiting and retaining physicians was compared against 13 variables; none was significantly related to the recruitment, and only two--numbers of service clubs and distance to nearest physician--were related to retention.

Community Health Services↗