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Biomedical subjects

D R Davis

Publications and source records attributed to D R Davis.

At least 127 records · Page 7Linked to original sources
PubMed1985

Survival and prognosis of patients with astrocytoma with atypical or anaplastic features.

This study confirms the importance of histologic tumor necrosis as a major prognostic variable in malignant glioma. Necrosis is present in glioblastoma multiforme (GBM), and absent in astrocytoma with atypical or anaplastic features (AAF). This paper evaluates 94 patients with AAF and 462 patients with GBM treated with radiation therapy with or without BCNU on 3 consecutive randomized protocols of the Radiation Therapy Oncology Group (RTOG) between 1974 and 1983. Multivariate analyses of the 556 patients confirmed histology as a significant independent variable that is prognostically relatively more important than Karnofsky performance status (KPS) and extent of surgery, and somewhat less important than age. The median survival for AAF was 36.2 months and for GBM was 8.6 months. In addition, separate multivariate analyses of AAf cases determined that the extent of surgery is a significant independent variable that is relatively more important than KPS, but less important than age. The median survival of AAF patients who underwent surgical excision was 46.8 months compared with 15.2 months for those biopsied (p less than .001).

Adolescent↗
PubMed1984

Is misonidazole neurotoxicity altered by the use of phenytoin and/or dexamethasone in RTOG 79-18 and RTOG 79-16?

An analysis of Misonidazole (MISO) neurotoxicity in RTOG 79-16 and RTOG 79-18 was undertaken to evaluate the incidence of neurotoxicity relative to dexamethasone dose and phenytoin use. MISO was administered as follows: 79-16 arm A, 1 gm/m2 5 days a week for a total of 10 gm/m2 in 2 weeks; 79-16 arm B, 2 gm/m2 twice weekly for a total of 12 gm/m2 in 3 weeks; and 79-18, 2.5 gm/m2 once a week for a total of 15 gm/m2 in 6 weeks. Practically all patients were on dexamethasone, and 240 out of 550 were on phenytoin for seizures. CNS toxicity and ototoxicity rates were no different between treatment groups with overall rates of 2.7 and 1.1%, respectively. Peripheral neuropathy (PN) was 5.1% in 79-16 arm A, 5.9% in 79-16 arm B, and 8.7% in 79-18. Phenytoin did not significantly alter CNS and PN toxicity rates. All ototoxicities occurred in patients not on phenytoin. There was no correlation between dexamethasone dose and incidence of neurotoxicity within each study. However, the incidence of (PN) for the combined studies was 6.4% (35/550) which is lower than 18.9% (85/449) for non-brain Phase III protocols where patients are rarely, if ever, on dexamethasone or other corticosteroids. Four hour and 24 hour plasma MISO levels, and 24 hour/4 hour MISO ratios did not correlate with toxicity.

Brain Neoplasms↗
PubMed1984

Reduction in duration of common colds by zinc gluconate lozenges in a double-blind study.

As a possible treatment for common colds, we tested zinc gluconate lozenges in a double-blind, placebo-controlled, clinical trial. One 23-mg zinc lozenge or matched placebo was dissolved in the mouth every 2 wakeful h after an initial double dose. After 7 days, 86% of 37 zinc-treated subjects were asymptomatic, compared with only 46% of 28 placebo-treated subjects (P = 0.0005). Side effects or complaints were usually minor and consisted mainly of objectionable taste and mouth irritation. Zinc lozenges shortened the average duration of common colds by about 7 days.

Administration, Oral↗
PubMed1984

Rapid radioimmunoassay for corticotropin in unextracted human plasma.

This RIA for corticotropin (ACTH) involves use of a commercially available antiserum and permits measurement of immunoreactive ACTH in unextracted plasma. The assay takes 2.5 days, detects as little as 5 pg/mL of plasma, and is specific: structurally and (or) biosynthetically related peptides do not cross react. Generally, data on dilutions of almost all human plasma specimens produce curves parallel to that for the ACTH reference standard. Values correlate well with those obtained by a well-established but more laborious RIA. We measured immunoreactive ACTH in normal subjects at various times of the day and after modulation of their pituitary-adrenal axis, and in patients with hypo- and hyper-secretion of ACTH. We conclude that the full range of immunoreactive ACTH values, which accurately reflect the status of the subject's pituitary-adrenal axis, can be quickly and easily determined in samples of unextracted human plasma.

Adrenocorticotropic Hormone↗
PubMed1983

Activated charcoal decreases plasma bilirubin levels in the hyperbilirubinemic rat.

The effectiveness of phototherapy and activated charcoal feeding for reducing plasma bilirubin concentrations was studied in the hyperbilirubinemic Gunn rat. The feeding of charcoal alone was just as effective in reducing plasma bilirubin concentrations as continuous phototherapy. An additive effect on reducing plasma bilirubin concentration was observed when phototherapy and the feeding of charcoal were administered together. The feeding of a 5% charcoal diet to weanling Gunn rats for 8 wk had no effect on growth rate.

Animals↗
PubMed1983

Improved embryonic survival in the jaundiced female rat fed activated charcoal.

The effects of reducing plasma bilirubin concentrations, by feeding activated charcoal, on embryonic survival in the jaundiced female Gunn rat was studied. The feeding of charcoal was effective in reducing plasma bilirubin levels by as much as 40%. Improved embryonic survival was observed in the charcoal-fed female rats in which 58% of the time-mated females were pregnant at necropsy. This was compared to 0% for the control females. Forty-eight percent of the charcoal fed and 7% of the control females that were continuously mated produced a live litter. Necropsy observations showed that 41-58% of the fetuses were in some stage of resorption. These findings support the hypothesis of an adverse bilirubin effect on reproduction in the female Gunn rat. It is suggested that jaundice during pregnancy may result in a risk to the unborn fetus.

Animals↗
PubMed1981

Can nutritional supplements help mentally retarded children? an exploratory study.

To explore the hypothesis that mental retardations are in part genetotrophic diseases (diseases in which the genetic pattern of the afflicted individual requires an augmented supply of one or more nutrients such that when these nutrients are adequately supplied the disease is ameliorated), we carried out a partially double-blind experiment with 16 retarded children (initial IQs, approximately 17-70) of school age who wee given nutritional supplements or placebos during a period of 8 months. The supplement contained 8 minerals in moderate amounts and 11 vitamins, mostly in relatively large amounts. During the first 4- month period (double-blind) the 5 children who received supplements increased their average IQ by 5.0-9.6, depending on the investigator, whereas the 11 subjects given placebos showed negligible change. The difference between these two groups is statistically significant (P less than 0.05). During the second period, the subjects who had been given placebos in the first study received supplements; they showed an average IQ increase of at least 10.2, a highly significant gain (P less than 0.001). Three of the five subjects who were given supplements for both periods showed additional IQ gains during the second 4 months. Three of four children with Down syndrome gained between 10 and 25 units in IQ and also showed physical changes toward normal. Other evidence suggests that the supplement improved visual acuity in two children and increased growth rates. These results support the hypothesis that mental retardations are in part genetotrophic in origin.

Adolescent↗
PubMed1981

Effects of special blue fluorescent light on hepatic mixed-function oxidase activity in the rat.

Phototherapy has been widely used in the treatment of neonatal hyperbilirubinemia. Recent reports, however, have indicated that fluorescent light may be toxic and mutagenic to mammalian cells. these findings suggest possible long-term side effects with the use of phototherapy. This study was undertaken to determine the effects of phototherapy on hepatic microsomal enzyme activity. The exposure of Sprague-Dawley and Gunn rats to special blue fluorescent light at an average irradiance of 1,200 microW/cm2 resulted in no significant changes in liver microsomal enzyme activity for aniline hydroxylase, p-nitroanisole-O-demethylase, ethylmorphine-N-demethylase, cytochrome c reductase or the quantity of cytochrome P-450. A significant decrease in aniline hydroxylase and p-nitroanisole-O-demethylase activity was observed when liver microsomes were exposed in vitro to special blue fluorescent light. Photoactivated bilirubin did not effect the activity of the mixed-function oxidase enzymes measured under the conditions of this study.

Aniline Hydroxylase↗
PubMed1980

Interaction of bilirubin and indocyanine green with the binding and conjugation of sulfobromophthalein by rat liver cytosol proteins.

The interaction of bilirubin and indocyanine green with sulfobromophthalein (BSP) binding and conjugation by rat liver cytosol proteins was studied. BSP bound to cytosol proteins X, ligandin and Z and the BSP-glutathione conjugate were isolated by sephadex gel chromatography. Neither bilirubin nor indocyanine green affected the binding of BSP to ligandin and Z protein. However, indocyanine green did significantly reduce BSP conjugation in both in vitro and in vivo experiments. Diethyl maleate significantly reduced liver glutathione levels and BSP conjugation. It is suggested that indocyanine gree competitively binds at the ligandin catalytic site whereas the primary binding site for bilirubin is probably a noncatalytic site.

Animals↗