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Biomedical subjects

J E Williams

Publications and source records attributed to J E Williams.

At least 19 recordsLinked to original sources
PubMed1992

The practice of complete denture prosthodontics by selected dental graduates.

Graduates of a dental school in the southeastern United States were surveyed for the procedures they used in practicing complete denture prosthodontics. Of the 530 graduates representing 15 graduating classes, 80% returned the questionnaires. Most respondents (94.8%) made complete dentures, but only 3.5% devoted more than 20% of their practice time to this phase of prosthodontics. In practice, the average graduate performed approximately one half of the techniques that had been judged academically to be clinically essential. Compliance decreased proportionately with the number of years in practice. Factors affecting compliance include the influence of peer practitioners and continuing education courses. The content of the predoctoral curriculum needs to be reviewed for its relevancy to continuing education and to dental practice.

Centric Relation↗
PubMed1992

Changes in concentration of adenosine triphosphate and adenosine diphosphate in individual preimplantation sheep embryos.

Concentrations of ATP and ADP were measured in 156 sheep embryos by means of an ultramicrofluorescence assay. Stages of preimplantation development measured included unfertilized oocytes through blastocyst-stage embryos. ATP concentrations remained constant through the 8-cell stage; then ATP decreased significantly (p < 0.025) at the morula stage and remained low through the blastocyst stage. ADP concentrations did not change throughout the embryonic stages measured. Decreased levels of ATP with constant levels of ADP caused the ATP:ADP ratio to decrease significantly (p < 0.025) between the 8-cell and morula stages. We suggest that the increase in glucose uptake by sheep embryos observed at the morula stage of development may be due, in part, to a decrease in the ATP:ADP ratio.

Adenosine Diphosphate↗
PubMed1992

Iron absorption and incorporation into red blood cells by very low birth weight infants: studies with the stable isotope 58Fe.

Measurements of iron absorption and incorporation into RBCs were obtained with the stable isotope 58Fe, administered as a reference dose, in 11 premature infants with birth weights between 780 and 1,520 g and gestational ages between 24 and 33 weeks. Each study included a timed stool and urine collection, nasogastric tube administration of a single dose of about 228 micrograms of 58Fe/kg of body weight (as FeSO4, with 10 mg/kg of vitamin C) between feedings, and blood samples before 58Fe (day 1) and then 2 weeks (day 15) later. Gastrointestinal absorption of the 58Fe dose as measured by fecal isotope balance was 41.6 +/- 17.6% (mean +/- SD). However, only 12.0 +/- 9.6% of the 58Fe dose (28.7 +/- 22.3% of the absorbed 58Fe dose) was incorporated into RBCs on day 15. 58Fe absorption and 58Fe incorporation into RBCs on day 15 were significantly correlated with the hemoglobin concentration and reticulocyte count on day 1. Transfusion history did not affect 58Fe absorption or 58Fe incorporation into RBCs. We conclude that concurrent measurement of 58Fe absorption with fecal monitoring and of 58Fe incorporation into RBCs permits a better understanding of the fate of iron ingested by premature infants than either measurement alone.

Algorithms↗
PubMed1992

Feeding wash water solids to sows during gestation and lactation: sow productivity, pig performance, and tissue compositions.

Diets containing 0, 10, or 20% dried wash water solids (WWS) from a milk processing plant were fed to 54 Yorkshire gilts (160 to 270 kg) for five parities. Feed intake, weight changes, and morbidity of sows were measured; number of pigs per litter, birth weight, and weight gain of pigs were also determined. Blood, tissue, and milk samples were taken from sows for hematological and mineral analyses, and tissue samples were taken from newborn pigs from each treatment per parity. Overall, initial sow weight, sow weight at weaning, and weight losses were not affected (P greater than .05) by treatment. At 107 d of gestation, overall weights decreased (P less than .05) linearly with level of WWS in the diet. The number of pigs per litter and weight of pigs were not affected (P greater than .10) by diet. Concentrations of NA (P less than .10) and Cd (P less than .05) were lower in kidney of sows fed 20% WWS, and concentrations of Zn were lower in bone and in kidney of sows fed the 20% WWS diet. The Sr and Ba concentrations increased (P less than .05, P less than .10) linearly in bone from sows with level of WWS in the diet. In pigs, concentrations of Mn in kidney and Zn in liver were lower for the 20% WWS treatment. In conclusion, feeding WWS to sows over five parities had minimal adverse effects on sow productivity and pig performance; the reduction in Zn concentrations in tissues of sows and pigs seemed to be related to the Ca content of WWS.

Animal Feed↗
PubMed1992

Cariostatic and ultraconservative sealed restorations: six-year results.

The objective of this clinical study was to determine the ability of an ultraconservative, sealed composite resin restoration, without a traditional cavity preparation and without the removal of the carious lesion, to arrest Class I caries. Tooth preparation was limited to placing a bevel in the enamel. These restorations were compared, over 6 years, with (1) ultraconservative, localized, sealed amalgam restorations with no extension for prevention and (2) traditional, unsealed amalgam restorations with the usual extension for prevention outline form. Caries was arrested by the ultraconservative, sealed composite resin restorations for 6 years. Complete sealant retention on the sealed amalgam restorations was somewhat lower than that on the sealed composite resin restorations; conversely, partial sealant retention was higher for the sealed amalgam group. The marginal integrity of the sealed amalgam restorations was significantly superior to that of the unsealed amalgam restorations. The sealant also protected Class I posterior composite resin restorations against wear.

Adolescent↗
PubMed1992

Sealed restorations: 5-year results.

This clinical study determined the feasibility of a sealed resin composite restoration to arrest dental caries using a minimal tooth preparation: a bevel in enamel only without removal of the carious lesion. These ultra-conservative sealed composite restorations placed over caries (CompS/C) were compared with ultra-conservative sealed amalgam restorations (AGS) that had no "extension for prevention". The CompS/C restorations were also compared with the traditional (unsealed) amalgam restorations (AGU) with the "extension for prevention" outline form. Caries progress, as determined by standardized radiographs, revealed that after 5 years caries remained arrested under the CompS/C restorations; the marginal integrity was similar for the CompS/C and the AGS groups, and exhibited highly significant superiority to the AGU restorations (Chi square, P less than = 0.00004). Complete sealant retention over the amalgam restorations (AGS group) was less than over the composite restorations (CompS/C), and conversely, partial sealant retention was higher for the AGS group. Sealants also appeared to protect the posterior composite restorations against wear.

Adolescent↗
PubMed1991

Evidence for involvement of both D1 and D2 receptors in maintaining cocaine self-administration.

Rats trained to self-administer cocaine (0.75 mg/kg/infusion) on an FR-5 schedule were treated with selective D1 or D2 antagonists. A69045, a D1 antagonist with no appreciable affinity for 5-HT receptors increased cocaine self-administration to 147, 172 and 167% of baseline at doses of 2.5, 5.0 or 10.0 mumol/kg, SC respectively. SCH-23390 (0.007, 0.015 and 0.030 mumol/kg, SC) increased self-administration to 116, 147 and 165% of baseline, respectively. Both D1 antagonists decreased responding in some animals at the highest dose tested. The D2 antagonist YM-09151-2 showed a similar profile, increasing cocaine self-administration at 0.01 and 0.016 mumol/kg, SC and suppressing responding by most animals at the dose of 0.03 mumol/kg, SC. These data give further support to the hypothesis that both D1 and D2 receptors are involved in maintaining cocaine self-administration.

Animals↗
PubMed1991

The radiological features of phylloides tumour of the breast with clinico-pathological correlation.

The mammograms of 13 patients with phylloides tumour of the breast are reviewed and the results correlated with clinical and histological features. Three patients had recurrent tumours. There is a strong association between phylloides tumour and fibroadenoma. Many of the tumours are radiologically indistinguishable from fibroadenomata and it is not possible to predict tumour behaviour on the basis of clinical and radiological features alone.

Adult↗
PubMed1991

Evaluation of dairy food processing wash water solids as a protein source: I. Forage intake, animal performance, ruminal fermentation, and site of digestion in heifers fed medium-quality hay.

Twelve ruminally, duodenally, and ileally cannulated (average initial BW 313 +/- 20 kg) and 27 intact Hereford heifers (average initial BW 256 +/- 17 kg) were used in two experiments to evaluate dairy food wash water solids (WWS) as a protein source in medium-quality hay diets. Heifers received a basal diet of orchardgrass hay (7.4% CP) and were assigned to one of three supplement treatments: control (C; .9% CP), WWS (18.8% CP)-, and soybean meal (SBM; 19.1% CP)-based supplements (fed at 1.5 kg of DM/d). Supplements were formulated to have similar ME concentrations. Ruminal ammonia concentrations were greater (P less than .10) for WWS- and SBM-supplemented heifers than for C heifers at most sampling times. Moreover, WWS and SBM increased (P less than .10) total VFA (mM) and acetate (mol/100 mol) and lowered propionate (mol/100 mol) at several sampling times. Ruminal fluid volume (liters) was unchanged (P greater than .10) by treatment; however, fluid dilution and flow rate (liters/h) were less (P less than .10) in C heifers than in heifers fed SBM or WWS supplements. Wash water solids and SBM supplementation increased (P less than .10) OM, NDF, and ADF digestibilities compared with C heifers. Feeding WWS and SBM supplements increased BW at 84 d (P less than .10) compared with C-supplemented heifers. Forage intake at 54 and 84 d by heifers supplemented with SBM or WWS was greater (P less than .10) than by C heifers. Control-supplemented heifers had the least, WWS intermediate, and SBM the greatest ADG at 84 d (P less than .10; .14 vs .35 vs .48 kg/d, respectively). These data indicate that WWS may be used as a protein source without serious adverse effects in heifers consuming medium-quality hay for 84 d.

Ammonia↗
PubMed1979

Microcinematographic demonstration of synchronous and asynchronous myoepithelial contractions in mouse submandibular gland rudiments in organotypic culture.

Time-lapse phase-contrast cinematography revealed contractile activity within mouse submandibular salivary gland rudiments in organotypic culture. Three types of contraction were distinguishable. In type I (voiding contractions), all portions of the gland contracted synchronously, and the active state ranged from 30 min to 2 hr. In type II (priming contractions), all portions of the gland contracted synchronously, but the active state was shorter, ranging from 4 to 10 min. In type III (churning contractions), isolated foci in lobules or secretory units throughout the gland contracted asynchronously and had very short active states of about 1 min. By electron microscopy, myoepithelial cells could first be demonstrated in submandibular glands developing either in vitro or in vivo, at 21 days postconception. Contractions in the cultured rudiments began as early as 18 days postconception. Since neither smooth nor striated muscle could be identified in these glands by electron microscopy, the contractions are believed to result from myoepithelial activity that apparently may begin before ultrastructural evidence of myoepithelial differentiation is clearly present. Although, for over a century, myoepithelium has been presumed to have a contractile function and indirect evidence has lent ample support to this presumption, the present study represents the first direct cinematographic demonstration and characterization of myoepithelial contractions, under conditions in vitro.

Animals↗
PubMed1979

Clinical progress of sealed and unsealed caries. Part II: Standardized radiographs and clinical observations.

At the present time, a trend has been shown that the progress of sealed caries is markedly slowed by sealant therapy as compared to open lesions. This fact has been substantiated by depth measurements, viable bacterial counts, standardized radiographs, and clinical observations. The radiographic and clinical observations agreed with the previously reported two parameters in confirming that (1) sealed cavities showed little or no change in depth and (2) open lesions showed a significant increase in depth as compared to sealed lesions.

Child↗
PubMed1979

Clinical progress of sealed and unsealed caries. Part I: Depth changes and bacterial counts.

1. A method for measuring depth changes in carious lesions has been developed. 2. A method for estimating bacterial viability in the study lesions has been developed. 3. Sealed cavities showed little or no change in depth over a 1-year period. 4. Open lesions showed a significant increase in depth as compared to sealed lesions. 5. Elimination or marked decrease in viable organisms under the sealant occurred.

Bacteria↗
PubMed1979

Electrophoretic isoenzyme patterns of the pathogenic and non-pathogenic intestinal amoebae of man.

Cultured stocks of Entamoeba hartmanni, Endolimax nana, Iodamoeba buetschlli and Dientamoeba fragilis were compared with the four Entamoeba histolytical groups already described (SARGEAUNT et al., 1978), by the electrophoretic patterns of three enzymes: glucose phosphate isomerase (GPI), phosphoglucomutase (PGM) and L-malate: NADP+ oxidoreductase (oxalacetate-decarboxylating) (ME). All the species were easily distinguished by their characteristic patterns.

Amoeba↗
PubMed1979

Experimental plague in the California ground squirrel.

In experiments to determine the current susceptibility to plague, it was demonstrated that 256 Yersinia pestis (a local strain of high virulence) were required to produce a 50% infectious dose (ID50) in California ground squirrels (Spermophilus beecheyi) that had been collected in southeastern Monterey County, California; 6,070 Y. pestis were required to produce a 50% lethal dose (LD50). (The LD50 was about 24 times the ID50.) The frequency of serologic response to the specific fraction 1 antigen of Y. pestis and mortality were dose-related. Approximately half of the squirrels inoculated with six to 6,070 Y. pestis survived without seroconversion, whereas antibody to specific fraction 1 antigen was always observed in squirrels that survived challenges of greater than or equal to 60,700 Y. pestis. However, titers never exceeded 1:64. The implications of these data for enzootic and epizootic transmission of plague in resistant squirrel populations are examined.

Animals↗
PubMed1979

Detrusor instability following surgery for genuine stress incontinence.

Nnety-two female patients with genuine stress incontinence, and with otherwise normal bladder function, were treated by a colposuspension operation. Pre-operative and post-operative clinical and urodynamic assessments were performed on all patients. Following surgery 17 of them were found to have detrusor instability.

Adult↗
PubMed1979

Serological response of chickens to Salmonella thompson and Salmonella pullorum infections.

Chickens were experimentally infected with Salmonella thompson (serogroup C, paratyphoid) and Salmonella pullorum (serogroup D). Five serological methods and one cultural method were used in detecting the infections. The microantiglobulin test was superior to all other methods for detection of paratyphoid (S. THOMPSON) infection and was followed in efficacy by the microagglutination test, rapid serum plate test, cloacal swab culture, macroscopic tube agglutination test, and rapid whole-blood test, in that order. Birds infected with S. pullorum showed much higher agglutinin titers than the birds infected with paratyphoid. The microagglutination and microantiglobulin tests were not significantly different for detection of pullorum infection and were followed in efficacy by the rapid serum plate, macroscopic tube agglutination, rapid whole-blood, and cloacal swab culture tests, in that order. The cloacal swab culture test was totally inadequate for the detection of pullorum infection.

Agglutination Tests↗