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Biomedical subjects

A C Peters

Publications and source records attributed to A C Peters.

At least 91 records · Page 5Linked to original sources
PubMed1986

Prechronic toxicity of o-benzyl-p-chlorophenol in rats and mice.

o-Benzyl-p-chlorophenol (BCP) is a major household and industrial germicide. Its prechronic toxicity was evaluated in male and female F344 rats and B6C3F1 mice. Treatment was by gavage in corn oil. BCP was slightly toxic after acute oral exposure, with high mortality at 4000 and 2000 mg/kg in rats and mice. Exposure to 12 oral doses of BCP at 1000, 500, 250, 125, 62.5, or 0 mg/kg body wt resulted in dose-related cecal dilatation and nephrosis in both rats and mice. Doses for the subchronic studies were based on the results of the 2-week studies. Ten animals were treated per dose per sex. Rats received 480, 240, 120, 60, 30, or 0 mg BCP/kg. Mice were treated with 1000, 800, 650, 500, or 0 mg BCP/kg. Animals were dosed 5 days per week for 13 weeks. Clinical signs related to dosing included urogenital staining in rats and rough/oily haircoats in mice. No effects on growth rate were seen in rats, but growth was retarded at the higher doses used in mice. Kidney weights increased in rats, and liver weights increased in mice. A decrease in thymus weight accompanied by a depletion in thymic lymphocytes (rats) or thymic necrosis (mice) occurred only in a high-dose animals. In both species, the kidney was the major target organ. In rats, there was an increase in incidence and severity of nephropathy and renal tubule regeneration. The lesions in mice primarily involved the renal cortex and included necrosis, casts, chronic inflammation, and regeneration of the renal tubules. No effects of BCP exposure in rats were seen in a broad spectrum of hematology or urinalysis parameters. Minor decreases in blood urea nitrogen, creatinine, and alanine amino transferase were detected in male and female rats. There were no biologically significant neurobehavioral effects in rats or immunotoxic effects in mice due to exposure to BCP. Thus, the kidney is the major target organ for BCP.

Animals↗
PubMed1985

Characteristics and bisphosphonate treatment of a patient with juvenile osteoporosis.

We studied a 13 1/2-yr-old boy with severe juvenile osteoporosis and multiple metaphyseal and vertebral fractures. Biochemically, there was evidence of non-PTH mediated excessive bone resorption, low intestinal calcium absorption, and a strikingly negative calcium balance. He was treated with (3-amino-1-hydroxypropylidene)-1,1-bisphosphonate, a bisphosphonate capable of inhibiting bone resorption rapidly, and had dramatic clinical and biochemical improvement. All indices of resorption were normal within a week after initiation of therapy and his 1,25-dihydroxyvitamin D concentration, which was only 9.6 pg/ml before treatment, rose to 62.4 pg/ml. These changes were associated with an increase in calcium absorption and positive calcium balance. Radiological improvement with healing of metaphyseal and one diaphyseal fractures and signs of sclerosis near the growth plates of the affected metaphyses and at the end plates of the vertebrae also occurred. (3-Amino-1-hydroxypropylidene)-1,1-bisphosphonate, therefore, with its rapid suppression of resorption and the accompanying hormonal changes, is a very effective treatment for juvenile osteoporosis. The primary defect of this obscure syndrome seems to be uncontrolled activity of metaphyseal osteoclasts; disturbances of vitamin D metabolism and of intestinal calcium absorption are secondary events.

Adolescent↗
PubMed1985

Human alpha and gamma interferon analogs in rabbits with herpetic keratitis.

Complete gene synthesis methods have been used to construct analogs of human interferons (IFNs): these include a consensus of the known human IFN-alpha S, designated IFN-alpha Con1 and a variant of human IFN-gamma, designated IFN-gamma 4A. These interferons, in purified form, were used topically against herpes simplex virus type 1 (HSV-1) induced ocular keratitis in rabbits. Eyes pretreated with IFN-alpha Con1 had decreased signs of infection and a lower incidence of HSV-1 positive trigeminal ganglia (3 of 14 positive) compared to the placebo treated (10 of 14 positive). IFN-alpha Con1 was as effective as natural IFN-alpha subtypes on a units basis, despite the very high specific activity of this analog. IFN-gamma 4A used under similar conditions do not result in beneficial effects with treatments beginning 24 or 48 hr before or 4 hr after virus inoculation. Rabbits with confirmed latent HSV infection were treated topically with IFN-alpha Con1 (10(6) units per eye each day) either before or before and after attempts to intentionally reactivate the infection by bilateral iontophoresis of 6-hydroxydopamine plus topical epinephrine treatment of the corneas. These IFN-alpha Con1 treatment regimens along with intentional reactivation during latency did not: (1) lessen the frequency of inducible ocular shedding episodes; (2) alter the mean time of 3-5 days between attempts to reactive latent infection and the appearance of HSV in tears; or (3) significantly change the incidence of HSV-positive trigeminal ganglia (83-100% HSV positive).

Administration, Topical↗
PubMed1985

[Infantile myositis].

An eleven-months-old boy with motor developmental delay, muscle weakness, hypotonia and normal tendon reflexes was diagnosed as having infantile polymyositis, histologically with a vasculitis component. Corticosteroid treatment was successful. At the age of 5 years he showed a normal motor pattern.

Humans↗
PubMed1985

[The Rett syndrome].

A 12-year-old girl with Rett's syndrome is presented. This syndrome, exclusively reported in girls, is characterized by a normal psychomotor development up to the age of 6 to 18 months, followed by developmental stagnation and then rapid progressive dementia, loss of purposeful use of the hands replaced by stereotypic hand movements, truncal ataxia, spasticity, seizures and microcephaly. The syndrome is not rare; prevalence has been reported as 0.65/10 000 girls.

Brain Diseases↗
PubMed1984

Fukuyama type congenital muscular dystrophy--two Dutch siblings.

Two Dutch siblings, diagnosed as suffering from Fukuyama type congenital muscular dystrophy (FCMD) on the basis of clinical, computerized tomography (CT), and muscle and brain biopsy findings, are reported. Hypoplasia of the chorioidea was observed for the first time in FCMD. Autopsy of the first case revealed the major pathological changes of FCMD, i.e. micropolygyria, loss of cytoarchitecture, hypoplasia of the pyramidal tract, leptomeningeal thickening. Heterotopias of nervous tissue in the spinal arachnoidal spaces were found. This is the first case in which brain tissue has been investigated on two separate occasions. In the biopsy specimen--at the age of 14 months--myelination was poor and astrogliosis marked. At autopsy--4 years later--myelination proved to be only slightly less than normal. However, white matter hypodensities on the successive CT's did not change. There is no ready explanation for this discrepancy. Typical FCMD is compared to FCMD-like cases from outside Japan. There are arguments in favor of the concept of a continuum of diseases--with the same (unknown) etiology--representing both typical FCMD and other types of congenital muscular dystrophy with CNS lesions.

Brain↗
PubMed1984

No evidence of carcinogenicity for L-ascorbic acid (vitamin C) in rodents.

Carcinogenesis studies of L-ascorbic acid were conducted by offering diets containing 0, 25,000 or 50,000 ppm L-ascorbic acid to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex for 103 wk. Survival of dosed and control female rats and of dosed and control female mice were comparable. Survival of high-dose male rats was slightly greater than that of the controls, whereas survival of high-dose male mice was significantly greater than that of the controls. There was no observed differences in neoplasms between treated and control groups that were considered related to L-ascorbic acid. In female rats, several lesions usually seen in aged animals showed a dose-related decline. Under the conditions of these studies, L-ascorbic acid given at 2.5% or 5.0% in the diet for 103 wk was not toxic or carcinogenic for male and female F344/N rats or for male and female B6C3F1 mice.

Animals↗
PubMed1984

Evaluation of lithium as an inhibitory agent of herpes simplex virus in cell cultures and during reactivation of latent infection in rabbits.

Lithium carbonate inhibited plaque formation of herpes simplex virus types 1 and 2 in rabbit kidney and Vero cells (50% effective dose, 435.5 to 490 micrograms/ml). Plasma lithium levels of 67 to 134 micrograms/ml were achieved by oral therapy in rabbits. However, neither ocular virus shedding nor virus-positive trigeminal ganglia were reduced after intentional reactivation of latent herpes simplex virus infection.

Animals↗
PubMed1983

The effects of valproic acid on liver function.

To study a possible enzyme-inducing potency of valproic acid (VPA) in children, serum gamma-glutamyltranspeptidase (GGT) activity in serum and D-glucaric acid (GLA) excretion in urine were measured in 32 epileptic children who were on sodium valproate monotherapy (29.6 +/- 10.3 mg/kg/day). VPA did not affect GGT activity, but it selectively enhanced GLA excretion. To approach this phenomenon experimentally an attempt was made to induce a similar effect in animals. In guinea pigs it was possible to provoke a VPA induced rise in GLA excretion. In addition, vacuolisation of the cytoplasm of the hepatic parenchymal cells was observed. The question of the possible relationship between VPA hepatotoxicity and stimulation of GLA excretion remains to be answered.

Animals↗
PubMed1982

Acute infratentorial traumatic subdural hematoma associated with a torn tentorium cerebelli in a one-year-old boy.

The case of a 1-year-old boy with an acute infratentorial subdural hematoma is presented. Surgical intervention revealed a bleeding vein at the edge of a right-sided tentorial tear. Traumatic tentorial tearing has been demonstrated previously only in neonates. Although computed tomography is the most effective method for recognition of this lesion, vertebral angiography may be mandatory for more accurate localization.

Brain Injuries↗
PubMed1982

Serum concentrations and enzyme induction in epileptic children treated with phenytoin and valproate.

In a group of 59 epileptic children treated with phenytoin (PHT) and valproate sodium (VPA), either alone or in combination, the following effects were studied: (1) the reciprocal effect on the serum levels of the two drugs, and (2) the enzyme-inducing effects of both drugs. VPA had no effect on PHT levels, but PHT significantly decreased VPA concentrations. PHT enhanced both gamma-glutamyltranspeptidase activity (gamma-GT) and D-glucaric acid excretion (GLA); these effects were potentiated by VPA. VPA alone did not affect gamma-GT, but significantly enhanced GLA.

Child↗