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Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 631 records · Page 35Linked to original sources
PubMed1988

Histochemical studies on glycosaminoglycans of odontogenic cysts.

Histochemical examination of odontogenic cyst connective tissue has demonstrated that hyaluronic acid is the predominant glycosaminoglycan present with lesser amounts of the sulphated glycosaminoglycans. Mast cells were frequently observed in the connective tissue, particularly just beneath the epithelium and may be responsible for the enhanced staining for heparin observed in this area. Local tissue metabolism and inflammation will contribute to the release of glycosaminoglycans from connective tissue into the lumenal fluid. Staining of glycosaminoglycans was generally minimal in the epithelium, although hyaluronic acid and chondroitin sulphate were detected in goblet cells. Glycosaminoglycans previously demonstrated in cyst fluids are probably derived from several sources in the cyst and will be important in its expansile growth.

Chondroitin Sulfates↗
PubMed1988

Prevalence of obesity in patients receiving depot antipsychotics.

Antipsychotic drugs have long been noted to cause pronounced weight gain, and drug-induced obesity can assume major clinical importance in long-term medication in the management of chronic schizophrenia. Obesity is associated with increased morbidity and may reduce compliance, leading to a return of psychotic symptoms. In a survey of 226 patients attending depot neuroleptic clinics in one inner London borough, it was found that the prevalence of clinically relevant obesity was four times that in the general population.

Adult↗
PubMed1988

Cerebral perfusion as a diagnostic marker of early Alzheimer's disease.

Clinical diagnosis of Alzheimer's disease (AD) is not fully satisfactory, and laboratory markers of this disease are not yet established. We report substantial regional Cerebral Blood Flow (rCBF) abnormalities in patients with documented early stages of the disease, when differential diagnosis is most critical. Thirty-six patients with carefully documented clinical diagnosis of early AD (mean disease duration, 3.25 +/- 1.80 years) and 12 elderly healthy controls participated in rCBF studies using the 133Xe inhalation method. Whole-brain perfusion was significantly (p less than 0.001) lower in the AD group, and a characteristic perfusion deficit was consistently found in temporoparietal cortex of the AD patients. Discriminant analyses demonstrated over 90% correct classification of the two groups. Two subgroups of patients with mildest disease manifestations were equally well discriminated. The similarity of these findings to those in late stages, which have been validated neuropathologically, offers indirect confirmation of validity and specificity. These results suggest that rCBF procedures may provide an accurate and sensitive laboratory marker for early AD.

Aged↗
PubMed1988

The spherical aberration of intra-ocular lenses.

Seidel aberration theory shows that the spherical aberration of a spherically surfaced intra-ocular lens cannot be made zero but only minimized and that the optimum shape is independent of the aberration of the rest of the eye (i.e. the cornea). The optimum shape of an intra-ocular lens correcting for spherical aberration is almost plano-convex with the more curved surface facing the cornea. The resulting total Seidel spherical aberration of the whole eye cannot be made zero unless the cornea has an asphericity much higher than the population mean.

Equipment Design↗
PubMed1988

Deaths from trench cave-in in the construction industry.

At least 70 US construction workers die each year in trench cave-ins, and Occupational Safety and Health Administration (OSHA) standards for work in trenches have been criticized as hard to understand and inadequate. This study examined 306 fatal cases, obtained mainly from OSHA investigations, from 1974 to 1986. Most of the deaths occurred in shallow trenches while digging sewer lines, and were caused by failing to shore or brace the walls of the trench. The risk of cave-in death was higher in young workers and those in small firms; only 12% of the deaths were in unionized companies. OSHA issued citations in 94% of the cases, with fines ranging up to $58,400; the average fine was $1,991 per death. Death due to cave-in is a significant risk for construction workers, and can be prevented by proper protective measures.

Accidents, Occupational↗
PubMed1987

Limitations of dipyridamole-echocardiography in effort angina pectoris.

The sensitivity of dipyridamole--2-dimensional (2-D) echocardiography was assessed for detection and localization of ischemia in 21 patients with severe chronic stable angina pectoris, a clearly positive exercise stress test response and multivessel coronary atherosclerosis. Regional wall motion during dipyridamole infusion (0.6 mg/kg intravenously over 4 minutes) was compared with control and recovery by 2 blinded observers in consensus. Transient regional wall motion abnormalities were observed in 11 patients. Angina and ST-segment changes occurred in 9 of these 11 patients with positive responses, but in none of those who showed no transient abnormality of regional wall motion. Localization of regional wall motion abnormalities correlated well with angiographic severity of coronary lesions. Endocardial area contraction, evaluated by a computerized system, was reduced significantly after dipyridamole administration in patients with a positive response (from 51 +/- 10% to 35 +/- 11%, p less than 0.001), whereas it did not change significantly in the others (from 43 +/- 6% to 42 +/- 8%). In the 11 patients with a positive response, coronary reserve assessed by exercise testing (modified Bruce protocol) was more impaired than in those with a negative response (time to 1 mm of ST depression 177 +/- 148 seconds and 472 +/- 179 seconds, respectively, p less than 0.01). In patients with severe angina and multivessel coronary artery disease, dipyridamole--2-D echocardiography appears to identify the vessel in which flow reserve is most limited. Although this information may be valuable, indications for the test are restricted to patients with severely limited exercise capacity.

Adult↗
PubMed1987

Identification of viral molecules recognized by influenza-specific human cytotoxic T lymphocytes.

Human cytotoxic T cells specific for influenza A virus were tested for recognition of each of the ten influenza A virus proteins expressed in target cells using recombinant vaccinia viruses. They recognized the matrix M1, polymerase PB2, and nucleoproteins of influenza virus in association with MHC class I antigens. These internal viral proteins were seen by CTL in conjunction with one or more of the available dependent HLA gene products. There was no detectable recognition of influenza virus surface glycoproteins in target cells.

Antigens, Viral↗
PubMed1987

A rating scale for amyotrophic lateral sclerosis: description and preliminary experience.

A rating scale has been developed to provide a quantitative estimate of clinical status and disease progression in amyotrophic lateral sclerosis (ALS). This scale includes assessment of swallowing, speech, and respiratory function, and both strength and function of upper and lower extremity musculature. The evaluation is relatively simple to perform and yields reproducible data for both a total ALS score and a score for each group of functions tested. A score of 30 points is normal; 164 points indicates maximal dysfunction. The total ALS score increased in a linear fashion in each of 74 patients followed for at least one year. Among patients, the rate of disease progression varied twenty-fold, with a continuous distribution from the slowest to most rapid course. Thirty-four percent of patients exhibited a rapid change of greater than 48 points in the year, predicting progression to a terminal stage in less than two years; 19% of patients exhibited a slow change of less than 13 points in one year, predicting progression to a terminal stage over at least five years. This ALS scoring system should permit more accurate assessment of drug efficacy in clinical trials and correlation of rates of progression with clinical variables.

Amyotrophic Lateral Sclerosis↗
PubMed1987

Evidence that PGE2 stimulates intestinal epithelial cell adenylate cyclase by a receptor-mediated mechanism.

These studies were performed to examine whether prostaglandin E2 stimulates intestinal epithelial secretion via a receptor-mediated or non-receptor-mediated activation of adenylate cyclase. Solubilization of epithelial cell adenylate cyclase with Lubrol PX, which separates the receptor moiety of the cyclase from the remainder of the complex, inhibited the prostaglandin E2 stimulation of the cyclase. A similar result was obtained with VIP, which activates adenylate cyclase via a receptor-mediated mechanism, whereas fluoride, gamma S-GTP, and forskolin, which activate the cyclase via non-receptor-mediated mechanisms, all stimulated solubilized adenylate cyclase. In addition, prostaglandin E2 and VIP both showed a dependence on GTP for adenylate cyclase stimulation while fluoride and forskolin did not. These data suggest that prostaglandin E2 activates intestinal mucosal adenylate cyclase by a receptor-mediated mechanism. The presence of such receptors lends support to the possibility that prostaglandins have a physiological role in the control of mucosal transport.

Adenylyl Cyclases↗
PubMed1987

Glycosaminoglycans in human salivary-duct stones.

These were demonstrated using histochemical and biochemical techniques. The presence of hyaluronic acid and chondroitin sulphate was confirmed by enzymic digestion. These substances may arise from inflammation in peri-ductal tissue.

Glycosaminoglycans↗
PubMed1987

The refractive increments of bovine alpha-, beta-, and gamma-crystallins.

The refractive increments have been determined for purified bovine alpha-, beta- and gamma-crystallins, using three different light sources. The values obtained were used to predict the refractive index gradient in the rat lens. Excellent agreement was obtained between the predicted and observed gradients.

Animals↗
PubMed1987

Early intervention with short courses of prednisone to prevent progression of asthma in ambulatory patients incompletely responsive to bronchodilators.

The effect of high orally administered doses of prednisone for 1 week early in the course of an acute exacerbation of asthma incompletely responsive to bronchodilators was examined in 41 patients randomly assigned to receive either prednisone or an identical appearing placebo. All 22 of the patients who received prednisone improved during the week of treatment, although one had a subsequent exacerbation 5 days after discontinuing the study medication. Of the 19 who received placebo, eight required rescue intervention (P = less than 0.004) in association with continued symptoms, increased frequency of metered-dose inhaler use, and decreased pulmonary function; the other 11 improved at about the same rate as those who received prednisone. Although the mean initial FEV1 was suggestively lower among those who did not improve and required intervention, there was considerable overlap with those who improved spontaneously, and no reliable distinguishing characteristics were found at entry into the study that could serve as predictors of those who would or would not improve spontaneously. There were no clinically important adverse effects from the prednisone. Because continued symptoms of asthma often result in emergency care or hospitalization, these data support early intervention with orally administered prednisone for acute exacerbations that do not respond fully to bronchodilators, at least in those patients with a prior history of a protracted course or emergency care.

Adolescent↗