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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 775 records · Page 43Linked to original sources
PubMed1990

Renal oncocytoma with cylindromatous changes: pathologic features and histogenetic significance.

We describe two cases of renal oncocytoma which showed an unusual light microscopic appearance characterized by nests of cells containing collections of eosinophilic hyaline material around and within oncocytic epithelial cell nests. Electron microscopy of the hyaline material showed a partly amorphous and partly lamellated structure, and immunohistochemistry for type IV collagen was positive. These cylindromatous changes are similar to the "glashelle Zylinder" of Billroth (Billroth T: Beobachtungen über geschwülste der speicheldrüsen. Virchous Arch [Pathol Anat] 17:357, 1859) described in adenoid cystic carcinoma and are most likely the result of an accumulation of basement membrane material in invaginations projecting into the surface of the basal plasmalemma. Since such invaginations occur in the normal distal tubule, our cases support origin of renal oncocytoma from distal tubular epithelial cells.

Adenoma↗
PubMed1990

AV nodal reentrant tachycardia.

During the past decade, the mechanisms of SVT have been discovered by intracardiac electrophysiologic studies. The differentiation of the various forms of tachycardia allows a more rational approach to therapy. Bedside maneuvers and the 12-lead ECG will identify the correct mechanism of SVT in the majority of patients. Diagnostic clues from the surface ECG include the position and morphology of the P wave, heart rate, change in rate with bundle-branch block, presence of AV block, and the initiation and termination of the SVT. With the use of bedside maneuvers and clues from the surface ECG, an intracardiac electrophysiologic study would be indicated only for recurrent SVT that is refractory to medical therapy and is potentially life-threatening.

Diagnosis, Differential↗
PubMed1990

Effect of pulsed ultrasound versus placebo on muscle soreness perception and muscular performance.

The purpose of this study was to compare the analgesic effect of pulsating ultrasound treatment and placebo on delayed onset of muscle soreness produced by an eccentric exercise bout. In addition, the effect of pulsed ultrasound on muscular performance following an eccentric exercise bout was studied. Eighteen untrained subjects were randomly assigned to: 1) ultrasound (A) [N = 6] over the areas of concentrated muscle soreness, i.e. proximal vastus lateralis and distal vastus medialis; 2) placebo ultrasound (B) [N = 6]; and 3) no therapeutic intervention (C) [N = 6]. Baseline data were recorded for maximum isometric knee extension contraction (MVC), maximum knee extension torque (MT), knee extension work (W), and soreness perception (SP). All values were subsequently reassessed 24 and 48 hours after intense muscular activity. Immediately following the 24 hour reassessment the A group received ultrasound treatment, the B group received placebo ultrasound, while the C group received no treatment. Percent deviation from baseline of SP, MVC, MT and W were significantly less for A than B and C (p less than 0.05) at 48 hours post muscle soreness bout. These data indicate that pulsed ultrasound accelerates restoration of normal muscle performance, and thus is effective in decreasing delayed onset of muscle soreness. The mechanism for decreasing soreness perception in the muscle is unknown, but may be related to decreasing intramuscular pressure and/or decreasing the inflammatory response.

Adult↗
PubMed1990

Binding and iron delivering of monoferric ovotransferrins to chick-embryo red blood cells (CERBC).

1. Both monoferric forms of OTf, each of about 80 kDa, bound to CERBC enough tightly, but at a lesser extent with respect to Fe2OTf with a Bmax in the order: 59Fe2OTf greater than OTf59FeC much greater than 59FeNOTf. 2. Fe2OTf competed, in equimolar ratio, with 59FeNOTf or OTf59FeC, lowering the Bmax value; a 10-fold molar excess of Fe2OTf almost abolished the binding of both labelled monoferric forms. Apo-OTf did not compete with the monoferric forms for binding to CERBC. Iron-saturated N- or C-terminal OTf half-molecules, each of about 40 kDa, were unable to displace the monoferric form. By contrast, the mixture of both half-molecules gave results very similar to Fe2OTf. 59FeNOTf and OTf59FeC were displaced by a molar excess of both unlabelled monoferric forms. 3. Uptake experiments showed that both monoferric forms of OTf were less effective in delivering iron to CERBC with respect to the diferric form, but, nevertheless, there was still an appreciable iron uptake which paralleled the binding behaviour, being the C-form slightly more efficient than the N-form.

Animals↗
PubMed1990

heterogeneity of creatine kinase isoenzyme MM in serum in myocardial infarction: interconversion of the "normal" and "abnormal" sub-bands by glutathione.

We used isoelectric focusing (IEF) in polyacrylamide gels to investigate the effects of glutathione on the sub-bands of serum creatine kinase (CK; EC 2.7.3.2) isoenzyme MM in acute myocardial infarction. The intensity of the "abnormal" sub-bands c (pI 7.25), e (pI 6.85), and g (pI 6.50) increased, and that of the "normal" sub-bands 1 (pI 6.91), 2 (pI 6.65), and 3 (pI 6.35) decreased, following serum incubation with reduced glutathione (GSH, final concentration 1.25 mmol/L). Further incubation with oxidized glutathione (GSSG, final concentration 5 mmol/L) reversed this change and restored the original pattern, whereas GSSG at 7.5 mmol/L caused sub-bands c, e, and g to disappear and sub-bands 1, 2, and 3 to be enhanced. Sequential incubation of serum with 2.5 mmol of GSSG and 7.5 mmol of GSH per liter produced the opposite sequence of events; i.e., the "abnormal" sub-bands disappeared then reappeared (and GSH at 10 mmol/L enhanced their reappearance). At higher concentrations, glutathione (GSH or GSSG) impaired the detection of the CK-MM sub-bands after IEF, an effect that was "quenched" by heat-inactivated serum of low CK activity. Likewise, the intensity of tissue CK-MM (corresponding to myocardium extracted into 100 mmol/L Tris HCl buffer, pH 7.4) was greatly enhanced by adding heat-inactivated serum to the tissue extract before IEF. We discuss the significance of these findings for the diagnosis of myocardial infarction.

Creatine Kinase↗
PubMed1990

Analysis of EMG activity and temporal components of gait during recovery from perturbation.

In ten able-bodied adults, gait was unexpectedly displaced in order to induce rapid dorsiflexion at heelstrike. Electromyographic (EMG) data were collected bilaterally from the tibialis anterior (TA) and gastrocnemius (G) muscles, and electrogoniometric data monitored joint angle changes in the ankle. Analysis of the data indicated initial EMG responses in the G of the perturbed limb and the TA of the contralateral limb at latencies of approximately 100 msec. It appeared that G activity served to decelerate the dorsiflexion of the ankle of the perturbed limb, whereas the TA accelerated dorsiflexion in the swing limb. Analysis of later EMG activity and foot-ground contact indicated that recovery after perturbation was easily completed during stance of the perturbed limb. Because of the comparatively minimal degree and velocity of displacement, further study with similar protocols might be considered appropriate to study balance problems in clinical populations.

Accidental Falls↗
PubMed1990

A deficit of bladder cancer in an Asian community in the UK.

Over a 10-year period, the incidence of bladder cancer in the local Asian community living within the Ealing hospital catchment area was compared with that in the indigenous population and that in England and Wales. A significantly reduced incidence was seen in the Asian community, using both comparisons.

Asian People↗
PubMed1990

Going the distance: rural health care in Texas.

Many doctors and hospitals are being squeezed out of rural and small-town Texas, and some of the population is beginning to suffer a lack of medical care comparable to that of underdeveloped countries. These articles consider the problem and present some options for improving health care delivery to rural Texans.

Delivery of Health Care↗
PubMed1989

Optimization and in situ detection of Escherichia coli beta-galactosidase gene expression in Dictyostelium discoideum.

We show that a fusion gene, containing the promoter and 5'-noncoding region of a Dictyostelium discoideum actin 6 gene linked to the Escherichia coli beta-galactosidase (beta Gal) gene (lacZ), directs the production of functionally active beta Gal in D. discoideum and that the enzyme can be detected by staining in situ; a procedure which will be of great value in analyzing cell-type-specific gene expression. We illustrate this by fusing lacZ to the promoter of the prespore-specific gene, D19, and localizing expressing cells in migrating slugs. Optimal expression requires the inclusion of termination and polyadenylylation signals and we describe pDDlac, a vector containing a multiple cloning site upstream from a lacZ-Dictyostelium terminator fusion, which can be used to analyze regulated promoters.

Amino Acid Sequence↗
PubMed1989

Effects of chlordecone on progesterone receptors in immature and adult rats.

The ability of the chlorinated pesticide chlordecone to induce the CNS (hypothalamus and preoptic area) plus pituitary and uterine progesterone receptors was examined in CDF-344 female rats following treatment with 25 micrograms estradiol or with 75 mg/kg chlordecone. In adult ovariectomized rats and in intact immature rats, estradiol increased progesterone receptors in neural and uterine tissues. This was in contrast to the effect of chlordecone. Chlordecone treatment of rats induced progesterone receptors in uterus of immature rats, but not in uterus of ovariectomized adult rats. In neither age group were CNS plus pituitary progesterone receptors increased following chlordecone treatment. These results suggest that the pesticide fails to mimic an estradiol-dependent event of substantial consequence to the CNS regulation of female reproductive functioning. These findings are discussed in terms of the possibility that chlordecone may, rather than mimicking, have the potential to attenuate estradiol's CNS effects. In addition to the effects of chlordecone on progesterone receptors, the effects of chlordecone in combination with estradiol were examined. Three temporal combinations between chlordecone and estradiol, which produce different effects on sexual behavior, were examined. The objective was to determine if chlordecone's inhibition of sexual behavior may have resulted from an attenuation of estradiol's production of CNS progesterone receptors. Chlordecone did not attenuate estradiol's elevation of CNS progesterone receptors under any of the three treatment conditions. Collectively, these studies demonstrate that chlordecone fails to mimic a well-defined and functionally significant effect of estradiol's interaction with the CNS estradiol receptor. However, they also suggest that the pesticide's inhibition of CNS estradiol events does not depend upon its attenuation of estradiol's induction of the CNS progesterone-receptor.

Animals↗
PubMed1989

Alterations in plasma lipoproteins and apolipoproteins associated with estrogen-induced hyperlipidemia in the laying hen.

The laying hen represents a physiological model in which the mechanisms of action of estrogens on lipid transport can be evaluated. The plasma lipoproteins in the laying hen were subfractionated into discrete particle species by isopycnic density gradient ultracentrifugation and the physicochemical properties and apolipoprotein contents of individual subfractions evaluated. The qualitative and quantitative aspects of this estrogen-specific profile were then compared to those of the immature chicken. As observed earlier, estrogens induced dramatic elevation in very-low-density lipoproteins (VLDL) (up to 900 mg/dl). Indeed, triglyceride-rich lipoproteins with densities up to 1.035 g/ml, i.e. VLDL and their remnants, behaved as a continuum which displayed little variation in size (20.5-21 nm), electrophoretic mobility (beta-like) and apolipoprotein content; apo B-100 (540 kDa) predominated while apo A-I (27 kDa), apo VLDL-II (19 kDa) and an apo-C-like protein (13 kDa) were present as minor components. The typical high-density lipoproteins (HDL) in the immature chicken were replaced by a lipoprotein population whose physicochemical properties were quite distinct. Thus these particles were distributed as a single, asymmetric peak over the density range 1.030-1.158 g/ml, a wide interval which overlapped that of apo-B-rich particles at its lower limit. The rho 1.030-1.158 g/ml lipoproteins were present at concentrations (approximately equal to 200 mg/dl) some twofold to threefold lower than those of HDL in immature birds. Furthermore, they displayed physical and chemical properties in common with both low-density lipoproteins (LDL) and HDL and were LDL-like in exhibiting beta mobility but HDL-like in size (9-15 nm diameter). Their protein moiety was also HDL-like in its predominant content of apo A-I; small amounts of apo VLDL-II and the apo-C-like protein were also detected. Substantial amounts of lipid were found at rho greater than 1.195 g/ml: such substances are absent in the immature chicken and may reflect the presence of vitellogenins. The hyperestrogenic state in the laying hen is therefore associated with major modifications in lipoprotein and apolipoprotein profile. Such modifications may be of relevance to clinical disorders involving estrogen-induced hyperlipidemia.

Animals↗
PubMed1989

Asthma: a provincial study.

To identify factors contributing to increased mortality and morbidity we prospectively evaluated 200 consecutive adult (greater than 17 years) asthmatic presentations (105 patients) referred to Gisborne Hospital over a 28 month period between 1985 and 1987 using a modified protocol adapted from previous national studies. In the moderate asthmatic group (113 presentations, 56%), 6% failed to use beta agonists prior to admission and 43% were not on regular steroid inhaler therapy. No patient had a crisis plan although 45 (22.5%) had received oral steroid therapy before admission. Poor drug compliance was twice as common in the Maori. Fifty-eight percent of patients were on regular long term oral theophylline whereas 48 (43%) patients with moderate and severe asthma were not on corticosteroid inhalers. We conclude that patient education and more liberal use of steroid inhalers have the greatest potential for improving morbidity and mortality.

Administration, Inhalation↗
PubMed1989

Preliminary crystallographic studies on duck ovotransferrin.

Crystals of duck ovotransferrin and duck apo-ovotransferrin have been grown from polyethylene glycol solutions. For both crystals, the space group is P2(1)2(1)2(1), the unit cell dimensions for the ovotransferrin are a = 49.6 A, b = 85.6 A, c = 178.7 A and for the apo-ovotransferrin a = 77.6 A, b = 98.8 A, c = 127.0 A, giving four molecules in the unit cell.

Animals↗
PubMed1989

Binding of various ovotransferrin fragments to chick-embryo red cells.

1. The ability of N- and C-terminal half-molecule fragments of hen ovotransferrin to interact with chick red blood cells (CERBC) has been studied under conditions that allow binding of the transferrin to transferrin receptors to take place, but not the delivery of iron to the cell. Two kinds of half-molecule fragments were used: (a) those which can associate with one another to give a dimer resembling native transferrin and (b) those which cannot associate in this way because they lack a few amino acid residues from their C-terminal ends. 2. Neither N nor C half-molecules alone can bind to the CERBC, but, when both are present, tight binding occurs. 3. Whether or not the half-molecules can associate with one another makes little difference to receptor binding. 4. Given that one of the half-molecules is iron-saturated, the presence or absence of iron in the contralateral half-molecule again makes little difference to receptor binding.

Animals↗
PubMed1989

Clonidine treatment of Alzheimer's disease.

A loss of cortical noradrenergic innervation may contribute to the intellectual deterioration in Alzheimer's disease. To test the hypothesis that noradrenergic replacement may confer symptomatic benefit, a double-blind, placebo-controlled therapeutic trial with clonidine hydrochloride (Catapres), a centrally active noradrenergic receptor agonist, was undertaken in eight patients with the clinical diagnosis of Alzheimer's disease. No statistically significant changes in cognitive function were found over a range of doses, including those that produced clinically observable side effects. These preliminary results indicate a need for alternative noradrenergic replacement strategies in Alzheimer's disease.

Aged↗