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Biomedical subjects

G W Small

Publications and source records attributed to G W Small.

At least 109 records · Page 6Linked to original sources
PubMed1991

Comparison of the Clearview Chlamydia test, Chlamydiazyme, and cell culture for detection of Chlamydia trachomatis in women with a low prevalence of infection.

Two antigen detection systems, Clearview Chlamydia (Unipath Ltd., Bedford, United Kingdom) and Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.), were compared with culture for the diagnosis of chlamydia infection in women attending gynecological clinics. Chlamydia trachomatis was isolated from 43 (4.5%) of the 965 women tested. In comparison with tissue culture, the Clearview Chlamydia and Chlamydiazyme tests had sensitivities of 79.0 and 74.4%, respectively, and both had a specificity of 99.6%. The results show that the Clearview Chlamydia test is comparable to Chlamydiazyme for the detection of C. trachomatis from endocervical specimens in a population with a low prevalence of infection.

Adolescent↗
PubMed1991

Mass hysteria among student performers: social relationship as a symptom predictor.

OBJECTIVE: In April 1989 an outbreak of illness suddenly afflicted student performers in Santa Monica, Calif., and an extensive investigation revealed no environmental cause. To clarify the details of the epidemic and determine whether mass hysteria occurred, the authors examined physical, psychological, and social factors that might have contributed to the outbreak. METHOD: Participating middle- and high-school performers were surveyed; 93% (N = 519) responded; cases were defined as students who had one or more symptoms during the outbreak. A stepwise logistic regression analysis was used to determine significant predictors of illness. RESULTS: Characteristic features of mass hysteria were present, including preponderance of illness in girls, symptom transmission by sight or sound, presence of hyperventilation, and evidence of psychological or physical stress. Symptomatic and asymptomatic groups differed in frequency of several physical and psychological variables, but observing a friend become sick was the best predictor of the development of symptoms. CONCLUSIONS: These results confirm earlier research demonstrating multiple psychological and physical factors that contribute to such outbreaks, particularly symptom transmission through social networks. Investigators should explore social transmission as an additional characteristic feature of mass hysteria in order to facilitate early identification of future outbreaks.

Achievement↗
PubMed1991

Recognition and treatment of depression in the elderly.

The author reviews clinical issues related to recognition of depression in elderly patients and provides a practical, systematic approach to diagnostic and treatment decision making. Factors complicating accurate diagnosis of geriatric depression include the presence of medical illness, dementia syndromes, cohort effects, ageism, and heterogeneity of patient populations. Age-related pharmacokinetic changes and polypharmacy need to be considered because they will increase an elderly person's sensitivity to medications. A variety of antidepressant drugs has been found to be safe and effective in elderly depressed patients, but some modification in their use is suggested. A systematic approach is provided to assist the clinician when confronted with this often complex and challenging patient population.

Age Factors↗
PubMed1990

Determination of physiological levels of glucose in an aqueous matrix with digitally filtered Fourier transform near-infrared spectra.

A procedure is described for the measurement of clinically relevant concentrations of glucose in aqueous solutions with near-infrared (NIR) absorbance spectroscopy. A glucose band centered at 4400 cm-1 is used for this analysis. NIR spectra are collected over the frequency range 5000-4000 cm-1 with a Fourier transform spectrometer. A narrow-band-pass optical interference filter is placed in the optical path of the spectrometer to eliminate light outside this restricted range. This configuration provides a 2.9-fold reduction in spectral noise by utilizing the dynamic range of the detector solely for light transmitted through the filter. In addition, a novel spectral processing scheme is described for extracting glucose concentration information from the resulting absorbance spectra. The key component of this scheme is a digital Fourier filter that removes both high-frequency noise and low-frequency base-line variations from the spectra. Numerical optimization procedures are used to identify the best location and width of a Gaussian-shaped frequency response function for this Fourier filter. A dynamic area calculation, coupled with a simple linear base-line correction, provides an integrated area from the processed spectra that is linearly related to glucose concentrations over the range 1-20 mM. The linear calibration model accurately predicted glucose levels in a series of test solutions with an overall mean percent error of 2.5%. Based on the uncertainty in the parameters defining the calibration model and the variability of the magnitudes of the integrated areas, an overall uncertainty of 7.8% was estimated for predicted glucose concentrations.

Calibration↗
PubMed1990

Synthesis and biological activity of novel quaternary ammonium derivatives of alkylglycerols as potent inhibitors of protein kinase C.

Alkylglycerols such as rac-1-O-octadecyl-2-O-methylglycerophosphochocholine (Et-18-OMe) have shown an inhibitory effect on the metastasis and growth of various cancer cell lines. Alkyl phospholipids have been shown to accumulate at the surface in several cell lines, the selectivity of which is still not clearly understood. A consequence of this action may lead to the inhibition of cell membrane related protein kinase C (PKC). The goal of this research was to develop ether lipid inhibitors of PKC to augment antineoplastic activity. This led to the synthesis and in vitro testing of a series of novel quaternary ammonium derivatives of alkylglycerols. The biological testing of these analogues on PKC stimulated with rac-1-O-oleoyl-2-O-acetylglycerol showed several analogues with inhibition comparable to that of Et-18-OMe.

Antineoplastic Agents↗
PubMed1989

Structure elucidation methodology for disaccharides based on carbon-13 nuclear magnetic resonance spectrum simulation.

Molecular mechanics techniques are used to derive structural parameters that allow carbon-13 nuclear magnetic resonance spectra of disaccharides to be modeled. On the basis of a collection of 40 disaccharide spectra, four linear models are derived that allow complete spectra to be simulated. On the basis of these 40 compounds, the average difference between simulated and observed chemical shifts is +/- 0.45 ppm. The majority of structural parameters used are based on interatomic distances computed from modeled three-dimensional atomic coordinates. Found particularly useful in modeling the disaccharide spectra are the effects of oxygen electron lone pairs and encodings of the structural environments of hydrogens alpha to the carbon whose chemical shift is being predicted. The computed models are examined, and their predictive ability is assessed. The potential application of the methodology to the structure elucidation of disaccharides is demonstrated.

Carbohydrate Conformation↗
PubMed1989

Cerebral glucose metabolic patterns in Alzheimer's disease. Effect of gender and age at dementia onset.

No previous study of Alzheimer's disease has, to our knowledge, assessed the effect of both age at dementia onset and gender on cerebral glucose metabolic patterns. To this end, we used positron emission tomography (fludeoxyglucose F 18 method) to study 24 patients with clinical diagnoses of probable Alzheimer's disease. Comparisons of the 13 patients with early-onset dementia (less than 65 years of age) with the 11 patients with late-onset dementia (greater than 65 years of age) revealed significantly lower left parietal metabolic ratios (left posterior parietal region divided by the hemispheric average) in the early-onset group. The metabolic ratio of posterior parietal cortex divided by the relatively disease-stable average of caudate and thalamus also separated patients with early-onset dementia from those with late-onset dementia, but not men from women. Further comparisons between sexes showed that, in all brain regions studied, the 9 postmenopausal women had higher nonweighted mean metabolic rates than the 15 men from the same age group, with hemispheric sex differences of 9% on the right and 7% on the left. These results demonstrate decreased parietal ratios in early-onset dementia of Alzheimer's disease, independent of a gender effect.

Age Factors↗
PubMed1989

Tricyclic antidepressants for medically ill geriatric patients.

The author reviews available data on tricyclic antidepressant (TCA) use in medically ill geriatric patients and data from controlled trials performed with physically healthy but depressed geriatric patients. Although these data point to the conclusion that medical illness appears to limit the use of TCAs in elderly patients, such agents as nortriptyline, desipramine, and doxepin can be used effectively. Guidelines are suggested to assist the clinician when confronted with this often complex and challenging patient population.

Aged↗
PubMed1988

Alkyl-linked diglycerides inhibit protein kinase C activation by diacylglycerols.

Alkylacylglycerols are synthesized when choline-phospholipids are degraded by a phospholipase C. This class of compounds has been shown to have biological activities; however, the mechanism of action is unknown. A series of alkyl-linked diglycerides were synthesized and tested for activity in an in vitro assay for protein kinase C. When protein kinase C activity was stimulated with the synthetic diacylglyceride analog 1-oleoyl-2-acetyl-sn-glycerol, the addition of alkyl glycerides caused a concentration-dependent inhibition of protein kinase C activity. Comparison of the protein kinase C inhibition by this series of 1-O-alkyl-2-acyl analogs revealed that both saturated and unsaturated long-chain groups in position 1 were effective and that dietherglycerols with short-chain moieties in position 2 were also effective. It is concluded from these studies that the biological activity of alkyl-linked glycerides may be expressed through protein kinase C inhibition.

Cell Line↗
PubMed1988

Training in geriatric psychiatry: will the supply meet the demand?

The number of geriatric patients with major psychiatric disorders is expected to grow along with the rising proportion of people age 65 and older. Despite recognition of this growth and increases in the training of geropsychiatrists, the supply of specialists is unlikely to keep up with the demand. The authors argue for greater resource expenditure in fellowship programs and a focus on training academic leaders to serve as role models for general psychiatrists and other primary care givers.

Aged↗
PubMed1988

Psychopharmacological treatment of elderly demented patients.

Elderly demented patients often suffer from accompanying psychiatric symptoms, including disturbances of mood and behavior, that may respond to psychotropic drug treatment. Despite the wide use of several medication groups--including antipsychotics, antidepressants, and sedative-hypnotics--data from double-blind clinical trials are limited. Some relevant controlled studies are reviewed, and guidelines for treatment based on the available data and clinical experience are described. Elderly demented patients can be treated psychopharmacologically. The choice of medication depends partly on its side effects. Initial dosages for the elderly should be lower than for younger adults.

Aged↗
PubMed1988

Data omitted from psychiatric consultation notes.

To assess how often psychiatric consultants omit written data from their consultation notes, the authors reviewed 78 initial consultation notes written by second-year psychiatric residents. Data considered essential for an adequate psychiatric evaluation were typically omitted. Categories that were observed to have the highest frequencies of missing data included family history of psychiatric illness (60.3%), history of substance abuse (44.9%), marital status (37.2%), previous psychotropic drug use (35.9%), previous psychiatric treatment (26.9%), and patient history of psychiatric illness (24.4%). The frequencies of omissions were significantly (p less than .001, except for the last item, p less than .01) higher than those from the consultation notes written by a second cohort of psychiatric residents who used a worksheet that listed data categories. The authors' findings argue for the use of worksheets delineating data categories to ensure that clinicians write adequate consultation notes.

Data Collection↗