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Biomedical subjects

M Long

Publications and source records attributed to M Long.

At least 19 recordsLinked to original sources
PubMed1995

Alterations in immune function following head injury in children.

OBJECTIVE: To investigate cellular and humoral immunity in children immediately after severe head injury and during the early recovery period. DESIGN: Prospective, observational study with factorial design. SETTING: Pediatric ICU of a university teaching hospital. PATIENTS: Fifteen children (median age 9.6 yrs, range 1.7 to 18) with head injury and Glasgow Coma Score of < or = 7. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Skin testing with seven standard antigens was performed and blood samples were obtained for the following measurements: total lymphocyte count and subsets; proliferative response to phytohemagglutinin, concanavalin A, and pokeweed mitogen; and immunoglobulin concentrations on days 1, 7, and 14 and 3 months after injury. The effect of patient plasma on phytohemagglutinin-induced proliferative responses of normal donor lymphocytes was also assessed at these times. Anergy was present in 71% of patients on day 1, 54% of patients on day 7, 31% of patients on day 14, and 18% of patients at 3 months. Total, helper, and suppressor T-cell counts were decreased on day 1, and the T-cell response to phytohemagglutinin was decreased on days 1, 7, and 14 compared with values at 3 months. B-cell counts were increased on day 1, followed by an increase in serum immunoglobulin concentrations 1 to 2 wks later. The B-cell response to pokeweed mitogen was unchanged over the 3-month study period. The phytohemagglutinin responses of normal donor lymphocytes were decreased when incubated with patient plasma obtained on day 7 after injury. CONCLUSIONS: Severe head injury in children is associated with depressed cell-mediated immunity. Plasma immunosuppressive factors may contribute to T-cell dysfunction.

Acute Disease↗
PubMed1994

Colonization of mechanical ventilation bags during use.

BACKGROUND: Colonization of patients' mechanical ventilation bags was examined to evaluate two criteria (days in use and appearance) for replacing the disposable adapter that interfaces with the patient. METHODS: Adapters used 1 to 2, 3 to 4 and 6 to 7 days formed groups I, II, and III, respectively (n = 29 to 67 per group). Another group (IA) contained 33 adapters used 1 to 2 days from patients intubated at least 7 days. Appearance of adapters was noted and adapters were swab cultured on nonselective medium. RESULTS: Analysis of variance indicated a difference in log colony-forming units per adapter between groups I and II (p = 0.032), but colony-forming units per adapter varied widely. Group III had a lower mean colony-forming unit count than group II. Groups I and II differed in variables other than days of use, but these confounding variables were eliminated by substituting group IA for group I. When adapter appearance versus colonization was examined by chi 2 test, a significant difference was found between adapters that looked "clean" and those with precipitate or with mucus or blood. CONCLUSIONS: For the subjects studied, colonization of adapters increased significantly between 1 to 2 and 3 to 4 days of use but varied widely. Appearance may be more useful than days in use as a criterion for changing adapters.

Adult↗
PubMed1994

Performance of case-finding tools for depression in the nursing home: influence of clinical and functional characteristics and selection of optimal threshold scores.

OBJECTIVE: To compare case-finding tools for depression in the nursing home setting and to evaluate effects of subject function, cognition, and disease number on test performance. DESIGN: Cross-sectional survey. SETTING: One academic and four community homes. SUBJECTS: One hundred thirty-four randomly selected, mildly cognitively impaired, functionally dependent residents. METHODS AND MEASURES: The Geriatric Depression Scale (GDS), Short Geriatric Depression Scale (SGDS), Center for Epidemiologic Studies Depression Scale (CES-D), and Brief Carrol Depression Rating Scale (BCDRS) were administered. The Structured Clinical Interview for DSM-III-R diagnoses was administered independently,. Operating characteristics and the effects of subject characteristics on test performance were evaluated using McNemar's test and logistic regression. Selection of "optimal" threshold scores was guided by Kraemer's quality indices and clinical judgment. RESULTS: Thirty-five subjects (26%) had major depression. No differences were found among the instruments in sensitivity (range 0.74-0.89), specificity (range 0.62-0.77), or area under the receiver operating curve (ROC) (range 0.85-0.91). Resident characteristics did not affect test performance. Quality indices showed the GDS and BCDRS met criteria for moderate to substantial agreement with the criterion standard, whereas the SGDS and the CES-D achieved only fair agreement. No change in threshold scores was warranted. CONCLUSIONS: The GDS and BCDRS performed well in the nursing home. As the GDS can serve as a both a case-finding and severity instrument, it is preferred. Use of brief, interviewer-administered tools may improve detection of depression in the nursing home.

Aged↗
PubMed1993

Natural selection and the origin of jingwei, a chimeric processed functional gene in Drosophila.

The origin of new genes includes both the initial molecular events and subsequent population dynamics. A processed Drosophila alcohol dehydrogenase (Adh) gene, previously thought to be a pseudogene, provided an opportunity to examine the two phases of the origin of a new gene. The sequence of the processed Adh messenger RNA became part of a new functional gene by capturing several upstream exons and introns of an unrelated gene. This novel chimeric gene, jingwei, differs from its parent Adh gene in both its pattern of expression and rate of molecular evolution. Natural selection participated in the origin and subsequent evolution of this gene.

Alcohol Dehydrogenase↗
PubMed1992

A calcium-binding protein in bile and gallstones.

Calcium salts are often present in the center of all types of gallstones. Matrix proteins are known to be essential for biomineralization and may therefore also be important in the formation and growth of gallstones. Other researchers have described an anionic peptide fraction of a biliary lipoprotein complex in bile and a low-molecular weight acidic glycoprotein present in gallstones. Our goal was to determine whether such a protein was present in bile and whether this protein has any calcium-binding properties. We identified a pigment-associated, highly acidic protein that precipitates from bile on addition of CaCl2 0.5 mol/L. In addition, the protein is selectively concentrated in cholesterol and pigment stones. We have, therefore, confirmed the findings of these other researchers, and we have extended the study of this protein's interactions with calcium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrates a single band (molecular weight < or = 14 kD) that reacts positively with cationic stains. The protein was shown to inhibit the precipitation of CaCO3 from a supersaturated solution. The capacity to bind calcium was further confirmed by autoradiography with 45Ca++ and by a membrane adsorption-binding assay. Calcium-induced aggregation was demonstrated by equilibrium dialysis and by quasielastic light scattering studies. Protein measured by Lowry's assay method and amino acid analysis constitutes only 2% to 4% of the harvested material. We speculate that a substantial lipid component may also be present.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1991

Isolation of Caenorhabditis elegans mutants lacking alcohol dehydrogenase activity.

Alcohol dehydrogenase (ADH) and the genes encoding this enzyme have been studied intensively in a broad range of organisms. Little, however, has been reported on ADH in the free-living nematode Caenorhabditis elegans. Extracts of wild-type C. elegans contain ADH activity and display a single band of activity on a native polyacrylamide gel. Reaction rate for alcohol oxidation is more rapid with higher molecular weight alcohols as substrate than with ethanol. Primary alcohols are preferred to secondary alcohols. C. elegans is sensitive to allyl alcohol, a compound that has been used to select for ADH-null mutants of several organisms. Allyl alcohol-resistant mutant strains were selected from ethylmethanesulfonate (EMS)-mutagenized nematode populations. ADH activity was measured in extracts from eight of these strains and was found to be low or nondetectable. These results form a basis for molecular and genetic characterization of ADH expression in C. elegans.

Alcohol Dehydrogenase↗
PubMed1991

Codon usage divergence of homologous vertebrate genes and codon usage clock.

This paper is concerned with the divergence of synonymous codon usage and its bias in three homologous genes within vertebrate species. Genetic distances among species are described in terms of synonymous codon usage divergence and the correlation is found between the genetic distances and taxonomic distances among species under study. A codon usage clock is reported in alpha-globin and beta-globin. A method is developed to define the synonymous codon preference bias and it is observed that the bias changes considerably among species.

Animals↗
PubMed1991

Evaluation of the stability of neuropsychological functioning after acute episodes of schizophrenia: one-year followup study.

Few studies have evaluated the longitudinal stability of neuropsychological deficits in schizophrenia. In the present study, 39 inpatients with DSM-III-R schizophrenia were administered a comprehensive battery of neuropsychological tests after achieving sufficient clinical recovery to warrant discharge, and again 1 year after the first assessment during a nonacute period. Significant improvement in neuropsychological functioning from the first to the second assessment was observed on several tasks, including the following: Trails A and B, Digit Symbol, Judgment of Line Orientation, recognition memory on the Rey Auditory Verbal Learning Test, the Wisconsin Card Sort, and Finger Tapping. These improvements were unrelated to treatment history, and were similar in first episode and chronic cases. For many patients, the improvement in functioning brought test performance into line with normative scores from test standardization samples. These results indicate that considerable improvement in neuropsychological functioning can occur in schizophrenic patients over the months following an acute episode of illness, and that recovery of cognitive functioning can occur after substantial clinical recovery from an acute episode of illness has already been achieved.

Adolescent↗
PubMed1991

Single-dose trospectomycin for chlamydial urethritis in men.

Trospectomycin is an aminocyclitol analog of spectinomycin with significant in vitro activity against Chlamydia trachomatis. A single 1-g intramuscular dose was administered to 10 men with symptomatic, culture-positive chlamydial urethritis. Trospectomycin was well tolerated but failed to eradicate chlamydial infection, as determined by cultures obtained approximately 1 week after treatment.

Adolescent↗
PubMed1990

Effect of electric field on erythrocyte sedimentation rate. II. Dependence on electric current.

We measured the electric current dependence of sedimentation curves of swine erythrocytes in a saline solution at the volume fraction of erythrocytes H = 0.091 and 0.220. The sedimentation curve fitted well to the exponential type equation l = a[1-exp(-bt)] at the upward initial electric current I0 = 0.50 mA, 1.01 mA and 1.50 mA, where l is the length of the medium layer at time t, and a and b are phenomenological parameters. The initial slope v0 of sedimentation curve was enhanced from 0.68 mm/hr at I0 = 0 mA to 2.85 mm/hr, 3.87 mm/hr and 5.50 mm/hr at I0 = 0.50 mA, 1.01 mA and 1.50 mA, respectively, for H = 0.220. We also made sedimentation measurements of erythrocytes in their own plasma at H = 0.220 and 0.316. Sedimentation curves coincided with the sigmoidal type equation l = l infinity/[1 + (t50/t)beta] at I0 = 0 mA and 0.50 mA, where l infinity is l at t----infinity, t50 is the time when the plasma level falls to l infinity/2 and beta is a constant. The maximum slope vmax of sedimentation curve increased from 13.29 mm/hr at I0 = 0 mA to 18.65 mm/hr at I0 = 0.50 mA for H = 0.220.

Animals↗
PubMed1989

The impact of a resident dog on an institution for the elderly: effects on perceptions and social interactions.

A longitudinal case study was made of a sub-unit of a nursing home to examine the perceptions and social interactions of patients and staff after introduction of a resident dog. A behavioral mapping procedure was used to determine staff and patient interactions 6 weeks before and 6 weeks and 22 weeks after the dog's arrival. Interviews were also conducted with patients and staff. Six weeks after the dog's arrival, a significant increase in frequency of interactive behaviors was seen for both staff and patients. By 22 weeks, behaviors for patients had reverted to base-line levels, while remaining high for staff.

Aged↗
PubMed1989

Source of methyl groups in brain and nerve tissue in the rat.

Previous studies that demonstrated that mouse brain accumulated significantly more radioactivity from subcutaneously administered 5-methyltetrahydrofolate labelled in the methyl group compared to the label in the folate moiety are open to two interpretations. The methyl group could have been transferred to another compound (probably methionine) prior to its transport into the brain. Alternatively, if plasma 5-methyltetrahydrofolate per se is significantly involved in the provision of methyl groups to brain and nerve tissue it would be expected that the folate moiety would be returned to the plasma to complete the cycle and thus would appear not to have been taken up. In this article, using competition experiments that exploit the differences in the mechanism of transport of methionine and 5-methyltetrahydrofolate into brain and nerve, evidence is presented that in the rat the methyl group of 5-methyltetrahydrofolate is transported after its conversion to methionine.

Animals↗
PubMed1987

The early effects of the prospective payment system on inpatient utilization and the quality of care.

Concern is often expressed that hospitals may be making cost/quality trade-offs under Medicare's prospective payment system. To evaluate the early effects of PPS on inpatient utilization and quality of care, we studied a cohort of 729 U.S. short-term general hospitals from nonwaivered states. We used a linear forecasting model to project 1984 figures based on trends from 1980 to 1983. We found no evidence that the quality of care deteriorated in 1984 for Medicare patients. Consultation rates remained constant, and in-hospital deaths and readmission rates were consistent with previous trends for the Medicare population. Overall, it appears that PPS has reduced hospital utilization without producing deterioration in the quality of care.

Coronary Care Units↗
PubMed1986

Interpretation of pulmonary artery wedge pressure and pullback blood gas determinations during positive end-expiratory pressure ventilation and after exclusion of the bronchial circulation in the dog.

Left atrial pressure (LAP) and pulmonary artery wedge pressure (PWP) were measured at different heights during graded increases in positive end-expiratory pressure (PEEP). Six healthy anesthetized dogs were placed in lateral decubitus positions with a balloon-tipped pulmonary artery catheter inserted in each lung. PWP in the gravitationally superior lung overestimated LAP at 15 and at 20 cm H2O PEEP (p less than 0.05). PWP in the dependent lung was virtually identical to LAP at all degrees of PEEP. Wedge blood could be aspirated through the distal lumen of the pulmonary artery catheters during balloon inflation at all degrees of PEEP except for 3 attempts. PCO2 in wedge blood in both the nondependent and dependent lungs at all degrees of PEEP was consistently lower than PCO2 in arterial blood (p less than 0.05). Wedge blood was arterialized, i.e., oxygen saturation greater than 95%, in all but 4 specimens. Surgical elimination of the bronchial artery supply to the lung in 3 dogs did not affect PWP or blood gas measurements. We conclude that in this animal model: (1) the tip of a pulmonary artery catheter must be below the level of the left atrium, Zone III location, to accurately reflect LAP at high degrees of PEEP; (2) arterialization of wedge blood samples does not guarantee that PWP reflects LAP; (3) bronchial artery blood supply does not affect PWP or wedge blood gas measurements, even at high degrees of PEEP.

Animals↗