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Biomedical subjects

D J Smith

Publications and source records attributed to D J Smith.

At least 361 records · Page 20Linked to original sources
PubMed1988

Immune properties of glucosyltransferases from S. sobrinus.

GTF activity was separated into water-insoluble (GTF-I) and water-soluble (GTF-S) polyglucan-synthesizing enzymes. Each preparation demonstrated a single band on 6% SDS PAGE. Only water-insoluble or water-soluble polyglucan was synthesized by the respective enzyme preparation. Rats were immunized, on Days 1 and 14, with either GTF-I or GTF-S in adjuvant. Animals were bled 13, 35 and 54 days after the initial immunization. Individual antisera were tested against either the GTF-I or the GTF-S for inhibition of radioactive glucose incorporation into glucan, and in gel diffusion, and by Western transfer analyses. The respective antisera reacted with the homologous, but not the heterologous enzyme in gel diffusion and Western transfer. GTF-I activity was not inhibited by antibody to GTF-S, but antibody to GTF-I inhibited GTF-I by 68%. GTF-S was inhibited by more than 60% by each of 3 anti-GTF-S sera. Only one anti-GTF-I serum inhibited GTF-S at as much as a modest 30% level. These data support the antigenic and functional distinctiveness of the GTF enzymes of S. sobrinus 6715.

Animals↗
PubMed1988

Patient discomfort during screen-film mammography.

Vigorous compression is required to minimize radiation dose and maximize image quality for screen-film mammography. Of 356 women who adequately completed a questionnaire following mammography, 171 (48%) reported mammography to be comfortable, 135 (38%) uncomfortable but tolerable, 39 (11%) very uncomfortable, and only 11 (3%) found the examination to be intolerable. Only 14 women (4%) indicated that they would not return for mammography at our facility in the future. Because of this high level of acceptance of compression by women, technologists and radiologists should not hesitate to use vigorous compression to optimize image quality and decrease radiation dose to the patient.

Adult↗
PubMed1988

Cross-sectional analysis of serum antibody to oral streptococcal antigens in children.

Antibodies to S. salivarius, S. sanguis, and S. mutans cells and to glucosyltransferases (GTF) prepared from these micro-organisms were measured in the sera of 133 infants and children by enzyme-linked immunosorbent assay (ELISA). IgG antibody activity to each cell type and GTP was present at birth (presumably derived from maternal transfer) and declined significantly thereafter. IgG antibody levels to S. salivarius and S. sanguis were next detected in young children (2 to less than 3 yr group). However, an increase in IgG antibody to S. mutans cells was not seen until children were older (4 to less than 8 yr group), possibly reflecting the later colonization of this organism. In contrast, IgG antibody to GTF of all three streptococcal species remained at low levels throughout the first four years of life. IgG antibody to S. mutans GTF was then the first to appear (4 to less than 8 yr group). Serum IgA antibodies to all GTFs were not detected until after this time. Fifteen sera were used to develop IgG immunoblots with the GTF antigens. Some positive sera (7/12) demonstrated reaction(s) with GTF from each of the three streptococcal species. Individual sera showed IgG antibody bonds to GTF from several serotypes of the mutans streptococci. No immunoblot reaction was observed with GTF and sera (3) from the four-to-seven-year and younger age groups. These results indicate the presence of serum antibody to bacteria and bacterial products associated with plaque formation very early in life and during and after the pre-adolescent years. The potential exists for this serum antibody to modulate bacterial colonization or accumulation in the oral cavity.

Adult↗
PubMed1988

Promotion of wound collagen formation in normal and diabetic mice by quadrol.

The rate of collagen deposition in implanted polytetrafluoroethylene (PTFE) tubing in non-diabetic and streptozotocin-induced (STZ) diabetic mice was measured during 14 days post-wounding. At the time of implantation, test groups received injections of either Quadrol [N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine], glucan, or buffer in an area adjacent to the wound site. The accumulation of collagen in the implants of Quadrol-treated non-diabetic animals was more than 200% above control on days 8 to 11 and was 50% above control on day 14. In Quadrol-treated STZ-diabetic mice, the collagen accumulation gradually increased from 50% above control on day 8 to 200% above control on day 14. Treatment with glucan increased the collagen accumulation in normal mice 200 to 300% above control from days 8 to 11 respectively and then 30% above control on day 14. Collagen accumulation in the implants of the glucan-treated STZ-diabetic mice was similar to the control group. These results indicate that Quadrol promotes in vivo collagen synthesis and that Quadrol may be effective as a stimulator of wound healing in diabetic and non-diabetic animals.

Animals↗
PubMed1988

Digital replantation and revascularization. Factors affecting viability, prognosis, and pattern of injury.

As experience with digital replantation increases, preoperative factors affecting outcome are being identified. Injury type, injury cause, ischemia time, and zone of injury have previously been reported. In addition, this report analyzes the effect of injury pattern and surgical group upon outcome. This data implies a multi-factor effect on the viability of replanted/revascularized parts. The lack of thorough reporting of the factors may account for the variability seen in success rates of various centers. An injury-injury type-injury level-ischemia time classification scheme has been proposed to standardize the reporting and the discussing of amputation/devascularization injuries. In clear cut situations, injury pattern may simply reflect type of injury (e.g. avulsion); however, in those situations where the mechanism is unclear, injury patterns may provide prognostic variables valuable in predicting replant viability. Further, a multi-group, multi-surgeon service functioning within a hospital may have results comparable to those of a single surgeon or single group practice.

Adolescent↗
PubMed1988

The effect of hemoglobin and hematocrit levels on free flap survival.

There has been experimental information suggesting that iatrogenic anemia may improve the survival of pedicled free flaps. This has been attributed to a decrease in blood viscosity secondary to hemodilution. The hemoglobin (Hb) and hematocrit (Hct) levels of 14 successful and 6 failed free flaps at the time of operation, during hospitalization, and at discharge are reviewed. There was no difference in Hb or Hct levels between successful and failed flaps. Reconstruction of traumatic defects showed an increased risk of failure. If flaps survived longer than 10-14 days, they were unlikely to fail subsequently. In conclusion, Hb and Hct levels in clinically acceptable ranges have no effect on free flap survival.

Blood Flow Velocity↗
PubMed1988

Role of liver plasma membrane fluidity in the pathogenesis of estrogen-induced cholestasis.

The role of liver plasma membrane (LPM) fluidity in the pathogenesis of intrahepatic cholestasis in rats was assessed by comparing the effects of ethinyl estradiol, a cholestatic agent, and spironolactone on membrane fluidity and bile flow. Spironolactone is a steroid that has some feminizing actions but that lacks the phenolic A ring necessary for estrogens to cause cholestasis. Bile flow was reduced 42% (p less than 0.01) by ethinyl estradiol and increased 22% (p less than 0.05) by spironolactone; however, both agents produced a significant reduction of membrane Na+, K+-ATPase activity (p less than 0.01) and fluidity (p less than 0.01). The decreased fluidity persisted in liposomes prepared from the total lipid extract as well as the phospholipid extract of these membranes. Both agents produced similar significant increases in the cholesterol ester content and cholesterol-to-phospholipid molar ratio of the membranes. In addition, ethinyl estradiol and spironolactone increased the membrane sphingomyelin content (15% and 11%, respectively); however, neither agent altered the fatty acid composition of the phospholipids. Because the decreased fluidity persisted in liposomes prepared from phospholipids extracted from the LPMs of treated rats, changes in membrane cholesterol are not the sole cause of the altered membrane fluidity. Rather, the increased sphingomyelin is at least partially responsible for these changes. Also, because ethinyl estradiol and spironolactone produce similar changes in LPM lipid composition and fluidity but disparate effects on bile flow, membrane fluidity as assessed by fluorescence polarization does not appear to be the rate-limiting determinant of bile flow in estrogen-induced cholestasis.

Animals↗
PubMed1988

Nutritional status of land-based U.S. Navy divers.

The nutritional status of 16 male, land-based U.S. Navy divers was assessed to collect baseline information for a cold water dive series. Diet records, blood samples, and 24-h urine collections were obtained and analyzed. The divers were deriving 17 +/- 1%, 40 +/- 2%, 32 +/- 2% of their calories from protein, carbohydrate, and fat, respectively. The remaining calories were furnished by alcohol (11 +/- 2%), an amount within the American Heart Association's guidelines. Crude fiber intake was low (3.7 +/- 0.4 g/d) whereas cholesterol (507 +/- 101 mg/d) and sodium intakes (4462 +/- 599 mg/d) were high. Mean intakes of vitamin B6 and folacin were below the Military Recommended Dietary Allowances. Mean blood concentrations and urinary excretion of minerals were normal but urinary sodium excretion was high. Results indicate that the divers' intakes of sodium and cholesterol were high, whereas intakes of complex carbohydrate and crude fiber were low. Whether these dietary patterns are suitable for extended dives, especially in cold water, remains to be determined.

Adult↗
PubMed1987

Differences in the constitutive forms of hepatic cytochrome P-450 in male and female adult beagle dogs.

Cytochrome P-450 isoenzymes were prepared from the solubilized liver microsomes of untreated adult male and female dogs, then separated into groups by high-performance liquid chromatography (HPLC). Partial purification was also completed through DEAE-52 cellulose and phosphocellulose ion-exchange chromatography. For comparison, solubilized hepatic cytochromes P-450 were obtained from rats dosed with phenobarbital (PB), beta-naphthoflavone (BNF) or pregnenolone-16 alpha-carbonitrile. Minimal molecular masses of cytochrome P-450 subpopulations were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. HPLC and ion-exchange chromatography results suggested the presence of two or three major and several minor cytochrome P-450 subpopulations. Three distinct groups were predominant in the female and two major and two or three minor subpopulations were found in the male. One of two isoenzymes prominent in BNF-dosed rats was present in the male but was missing in the female dog; another minor canine cytochrome similar to one found in PB-dosed rats was missing from the male. These data indicate qualitative and quantitative sex-dependent differences in the constitutive cytochrome P-450 populations of the dog and suggest that HPLC analysis may be useful for the interpretation of toxicological studies where microsomal enzyme induction is suspected.

Animals↗
PubMed1987

Isolation and characterization of a polarized isolated hepatocyte preparation in the skate Raja erinacea.

Hepatocytes of the small skate (Raja erinacea) were isolated by collagenase perfusion and evaluated by a variety of functional and morphologic criteria. Cell yield was 1.45 X 10(8) +/- 1.3 X 10(7) cells per isolation, and as long as 8 h after isolation 98% of the hepatocytes excluded Trypan blue and no leakage of lactate dehydrogenase (LDH) or cell associated potassium could be detected. Oxygen consumption averaged 1.6 +/- 0.5 nmol/min/mg cell protein, was not stimulated by 1 mM succinate, and also remained stable for up to 8 h following isolation. However, 2,4,-dinitrophenol (5 X 10(-5) M) produced a 55% increase in oxygen utilization while ouabain, (1 mM) or sodium removal decreased oxygen consumption by 31 +/- 6 and 33 +/- 7%, respectively, indicating that a significant portion of the cells energy utilization is coupled to the activity of plasma membrane Na+, K+-ATPase. Light microscopic studies showed that the individual hepatocytes had diameters of 28 +/- 5 microns and contained large lipid droplets. Electron microscopy revealed groups of three to five cells with normal ultrastructure and tight junctions and desmosomes surrounding a single bile canaliculus. These studies indicate that skate hepatocytes can be isolated in high yield that retain their structural polarity in the form of clusters of cells formed around a single bile canaliculus. These hepatocytes remain morphologically intact and metabolically stable for a prolonged period of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Immunological features of minor salivary gland saliva.

Concentrations of IgA, IgG, IgM, and IgA subclasses were measured in 138 pairs of parotid gland saliva (PS) and labial gland saliva (LS), using an enzyme-linked immunosorbent assay (ELISA) technique in which levels of Ig were quantitated using affinity-purified anti-heavy chain reagents for capture and development. Both PS and LS were collected simultaneously during sour lemon drop stimulation. As previously observed, IgA was the dominant immunoglobulin in both salivary fluids, the concentrations of which were highly correlated within the subjects studied. The mean proportion of IgA1 to total IgA was slightly higher in LS (0.66), compared with PS (0.60). Little IgM was usually detected in either secretion. In contrast, LS had IgG concentrations (mean, 8.1 micrograms/ml) which were significantly higher (P less than 0.001) than those found in parotid saliva (mean, 0.3 micrograms/ml). Over 30% of the subjects had mean LS IgG levels above 10 micrograms/ml. The mean percentage of LS IgG to IgA was 20% in the 138 samples tested. Gel filtration of pairs of PS and LS from four individuals revealed IgM, IgA, and IgG to elute in positions commensurate with pentameric IgM, secretory IgA, and monomeric IgG. Little or no monomeric IgA could be detected. These results suggest that, in addition to IgA, the IgG isotype may also be important in antibody-mediated phenomena which occur in oral microenvironments bathed by minor salivary gland secretions.

Adult↗
PubMed1987

Phenotypic analyses of mononuclear cells recovered from healthy and diseased human periodontal tissues.

Mononuclear cells were recovered from the gingival tissues of normal individuals and from patients with periodontal disease. Lymphocyte phenotypic markers were identified by immunofluorescence after reaction with monoclonal antibodies to T-cell subset markers. The normal tissues exhibited T4/T8 ratios almost identical to those in the peripheral blood. The diseased tissue cell ratios were significantly reduced, in both the adult periodontitis and the juvenile periodontitis groups (P less than 0.01 and P less than 0.02, respectively), indicating alterations in the T-cell subset distribution in these tissues. Each diseased patient showed a much decreased T4/T8 ratio in the gingival lymphocytes when these were compared with the peripheral blood ratio from the same patient. The T4/T8 ratios of the more severe sites were significantly lower than those of the less severe sites in the same disease category. The decreases in subset ratios could be attributed to statistically significant reductions in T4+-lymphocyte recoveries relative to peripheral blood and also to slight relative increases in T8+ lymphocytes. A highly significant (P less than 0.001) correlation between the average probeable periodontal pocket depth and the T4/T8 ratio of each disease category was demonstrated. The relative recoveries of B cells from the various tissues did not differ between diseased and normal tissues. It is suggested that T-cell regulatory expression in gingival tissues is distinct from peripheral blood regulatory expression and that there is a local immunoregulatory imbalance in periodontal disease.

Adolescent↗