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Biomedical subjects

W L Williams

Publications and source records attributed to W L Williams.

At least 73 records · Page 4Linked to original sources
PubMed1982

Radiation-induced augmentation of the response of A/J mice to SaI tumor cells.

Whole-body exposure of A/J mice to low doses (5-25 rads) of ionizing radiation immediately prior to the inoculation of 10(4) Sarcoma I (SaI) cells results in smaller tumors than are observed in sham-irradiated control animals. The irradiated group also contains a greater proportion of mice that fail to develop tumors or that demonstrate tumor regression. Low-dose augmentation is 1) less pronounced in recipients that have undergone splenectomy; 2) not evident in adult thymectomized-lethally irradiated-bone-marrow-restored (ATxXBM) animals, where the opposite effect is seen (eg, low-dose enhancement of tumor growth); and 3) abolished by the administration of normal syngeneic spleen cells unless the latter have been depleted of T cells. On this basis, a very radiosensitive T cell with suppressor activity is implicated in this phenomenon. Low-dose exposure at various times prior to tumor inoculation suggests that this cell regenerates in 5-10 days after irradiation.

Animals↗
PubMed1980

Potentiation of the cGMP-induced guinea pig acrosome reaction by zinc.

The addition of 8 bromo cGMP (10 mM) immediately (approximately 2 min) upon suspension of Guinea pig sperm in glucose-free BWW medium induces a significant number of acrosome reactions within minutes. The simultaneous addition of micromolar concentrations of ZnCl2 (25-1000 microM) potentiates the cGMP effects. Mid-micromolar concentrations were able to dramatically increase the percentage of acrosome reactions by a factor of 6.5 over 8 bromo cGMP alone. The induction of acrosome reactions was dependent upon external Ca++, and it is suggested that in this species Zn++ functions by affecting cyclic nucleotide metabolism and/or Ca++ flux.

Acrosome↗
PubMed1980

Antitumor agents XLI: Effects of eupaformosanin on nucleic acid, protein, and anaerobic and aerobic glycolytic metabolism of Ehrlich ascites cells.

The major effect of eupaformosanin as an antineoplastic agent on Ehrlich ascites cell metabolism was to inhibit deoxyribonucleic acid synthesis, specifically at deoxyribonucleic acid polymerase and thymidylate synthetase enzymatic sites. Both pyrimidine and purine systems of Ehrlich ascites were marginally inhibited. Ribonucleic acid synthesis and messenger and ribosomal polymerase activities also were suppressed. Cyclic adenosine monophosphate levels were increased significantly, which correlated with the drastic reduction of histone phosphorylation. Eupaformosanin also suppressed a number of glycolytic and Krebs cycle enzymes as well as oxidative phosphorylation in vitro. All of the inhibited enzymes are known thiol-bearing enzymes that can undergo a Michael-type addition with the alpha-methylene-gamma-lactone moiety of eupaformosanin, as shown with other sesquiterpene lactones.

Aerobiosis↗
PubMed1980

New antifertility agents active in the rabbit vaginal contraception (RVC) method.

Zinc salts in aqueous K-Y Jelly are effective vaginal contraceptives in the rabbit. The minimum effective dose is 54 to 60 mg Zn/ rabbit as acetate, gluconate or lactate. Zinc salts added to suboptimal doses of Ortho-Gynol Jelly or Delfen Cream improves the vaginal contraceptive efficacy of these products. Twenty-seven mg zinc/rabbit as lactate or acetate and 28 mg zinc/rabbit as sulfate or chloride in 0.1 to 0.5 ml of cream or jelly are effective. Gossypol is effective at a dose of 2 mg/rabbit. Although there is some rationale for their use, manganese has no antifertility effect and valium appears to promote fertility. The rabbit vaginal contraception (RVC) method shows undesirable variation but use of sufficient animals yields logical and reliable results. Artificial insemination instead of breeding appears to decrease variation.

Animals↗
PubMed1980

Blood pressure reduced by methylene chloride. A study in spontaneously hypertensive rats.

Effects of methylene chloride (CH2Cl2) on blood pressure (BP), body weight, plasma renin activity, hepatic histological structure of spontaneously hypertensive rats (SHRs) and normotensive control rats (NCRs) were studied. Administration of 0.15 mL/100 g/day CH2Cl2 to SHRs for five days reduced the BP from 172 +/- 7 mm Hg (mean +/- SEM) to 155 +/- 6 mm Hg without changing the plasma renin activity. The same regimen did not change the BP of NCRs. A weekly injection of 0.15 mL/100 g/day of CH2Cl2 for five consecutive weeks failed to significantly alter the BP of either SHRs or NCRs. The polyhalogen, whether administered daily or weekly, did not affect the body weight of either SHRs or NCRs. Administration of CH2Cl2 daily for five days produced an extensive but reversible hepatic centrolobular loss of glycogen in both SHRs and NCRs. No other changes were observed in the livers.

Angiotensin I↗
PubMed1980

A family practice education system based on patient care outcomes in family practice settings.

The philosophy, goals, objectives, methodology, and results of a family practice faculty development program are described. Developing family practice educators who will create an education system based on patient care outcomes in family practice settings is the central philosophical purpose of this faculty development program. On completion of the program all participants recognized the essential nature of this philosophical goal and were more comfortable and confident in their ability to: (1) determine resident learning needs; (2) organize curriculum units; (3) use different teaching techniques; and (4) understand their own personal teaching needs and interests. The implications of these changes for developing a family practice curriculum based on patient needs are described.

Faculty, Medical↗
PubMed1979

Dissolution of rabbit zona by sperm acrosomal extract: effect of calcium (1).

The acrosomal extracts from rabbit spermatozoa were more effective in dissolving the zona pellucida of the rabbit ova in the absence than in the presence of Ca2+. The extracts had high proteolytic activity but low esterolytic activity at alkaline pH in which pH effective zona hydrolysis occurred. The results suggest that acrosomal proteinases in addition to acrosin may be involved in the zona penetration.

Acrosin↗
PubMed1979

Toxicity of Secalonic acid D.

Toxicity of secalonic acid D was examined by using lethality, growth retardation, and histopathology as indexes. The ip LD50 values of 37, 31, and 27 mg/kg were obtained for Charles River CD-1, Texas (ICR), and Sprague-Dawley (CF-1) strains of mice, respectively. The ip LD50 was 52 mg/kg in female CD-1 mice. The iv LD50 was 25 mg/kg in CD-1 male mice. Oral LD50 values of 400 mg/kg in male CD-1 mice and 25 and greater than 400 mg/kg in Sprague-Dawley day-old and weanling (21 d) rats of both sexes, respectively, were obtained. Doses of 20 mg/kg or more ip retarded growth and doses of 30 mg/kg or more ip were lethal to CD-1 mice. Oral doses required to produce such effects in day-old rats were 5 and 20 mg/kg (or higher), respectively. All ip doses of secalonic acid D caused pulmonary atelectases and foccal peritonitis in male CD-1 mice. The latter involved surfaces of abdominal viscera and produced limited subcapsular necrosis of hepatic parenchyma. Exposure to a single lethal dose iv (25 mg/kg or more) of secalonic acid D caused limited hepatic portal necrosis but no peritonitis or other associated local effects observed in CD-1 male mice after ip exposure. Cytoplasmic liposis and loss of glycogen and RNA from hepatocytes were observed in a single mouse receiving 50 mg/kg iv. Death resulting from cardiac and/or pulmonary insufficiency was suggested by atelectasis, pulmonary hemorrhages and edema, and massive atrial dilation in mice that died after lethal ip or iv doses of secalonic acid D. Five daily sublethal ip doses in CD-1 male mice resulted in dose-dependent mortality (LD50, 11.5 mg/kg) indicating cumulative effects.

Animals↗
PubMed1979

In vitro capacitation of ejaculated rabbit spermatozoa.

Prior to fertilization mammalian spermatozoa undergo physiological changes in the female reproductive tract. These changes are collectively known as capacitation. In essence capacitation is a further differentiation that the sperm cell must acquire beyond the maturational changes that it undergoes in the epididymis. Although capacitation in vitro has been easily achieved in rodents, its accomplishment in the rabbit is inconsistent and difficult. We report here successful in vitro capacitation of ejaculated rabbit sperm, assessed by in vitro and in vivo fertilization of rabbit ova. Sperm were used from pooled ejaculates collected from bucks of proven fertility since sperm collected from individual bucks resulted in significant differences in fertilization levels. Conditions favoring in vitro capacitation were: (1) extended incubation time of 12 h, (2) addition of 20% heated rabbit serum to incubation medium, and (3) an atmosphere of 5% CO2, 8% O2, and 87% N2 during incubation. In vitro capacitation of sperm under these conditions resulted in 67% fertilization compared to 89% for control sperm capacitated for 13 h in the uterus.

Animals↗
PubMed1978

Rabbit acrosin: immunological dissimilarity to rabbit trypsin (1).

Antibodies obtained from guinea pigs injected with rabbit pancreatic trypsin together with antibodies raised in rabbits against bovine acrosin or bovine pancreatic trypsin were reacted against various mammalian trypsins and acrosins in double diffusion tests. The results of immunodiffusion analyses reveal antigenic dissimilarity between rabbit acrosin and rabbit trypsin.

Acrosin↗
PubMed1978

Perirenal malignant Schwannoma presenting as renal cell carcinoma.

Clinical and radiographic evaluation of a fifty-six-year-old male with microscopic hematuria led to radical nephrectomy for renal cell carcinoma. Histologic examination by light and electronmicroscopy was most compatible with malignant schwannoma. The tumor was close to the kidney without actual renal involvement. This case is of interest for both its rarity and its unusual presentation.

Carcinoma↗
PubMed1978

Analysis of increasing antibiotic resistance of Klebsiella pneumoniae relative to changes in chemotherapy.

Three antibiotic-resistant strains of Klebsiella pneumoniae responsible for outbreaks of systemic infection in a hospital nursery were analyzed. Each organism emerged after prolonged use of a drug to which it was resistant. The first strain (RO16) produced neomycin phosphotransferase and contained three plasmids with molecular weights of 24, 25, and 30 X 10(6) daltons, respectively. Resistance to ampicillin, carbenicillin, neomycin, and kanamycin was transferred by conjugation at a frequency of 10(-6). The second strain of K. pneumoniae (RO106) produced gentamicin adenyltransferase and maintained aminoglycoside resistance only when propagated in antibiotic-containing medium. DNA analyses revealed eight species of plasmid DNA: one species with a molecular weight of 70 X 10(6) daltons apparently accounted for conjugal transfer of resistance to ampicillin, carbenicillin, chloramphenicol, and streptomycin. The third strain (RO180) was resistant primarily to colistin and lacked plasmids. Control of the outbreak due to this strain was achieved by aminoglycoside therapy.

Aminoglycosides↗