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Biomedical subjects

J Morgan

Publications and source records attributed to J Morgan.

At least 127 records · Page 7Linked to original sources
PubMed1997

Parachuting injury surveillance, Fort Bragg, North Carolina, May 1993 to December 1994.

Surveillance for parachute-related injuries was conducted at Fort Bragg, North Carolina, between May 1993 and December 1994. During this 20-month period, lower-extremity injuries (27% of all injuries), axial skeletal (back and neck) strains and sprains (19.3%), and closed head injuries (18.4%) were the leading causes of injury. The incidence of injuries requiring emergency care was 8/1,000 jumps. This rate is well within the jump injury planning estimate, suggesting that airborne training and operations are conducted in a safe and effective manner at Fort Bragg.

Adolescent↗
PubMed1997

Heat-related illness and death, Wisconsin, 1995.

This article examines heat-related illnesses and deaths that occurred in Wisconsin during the summer of 1995, which was among the warmest seasons on record. Death certificates that listed heat exposure as a contributing or underlying cause of 154 deaths and ambulance run reports for 454 heat-related emergency calls were analyzed. The time and place of these events and patient information were used to evaluate risk factors such as age, medical condition, physical activity, and environmental temperature. Three-fourths of the deaths and nearly half of the heat-related illnesses occurred during or shortly after two days of intense heat. Major risk factors for these heat-related illnesses and deaths included age, underlying chronic illness, physical exertion, and lack of air-conditioning. To reduce the number of illnesses and deaths that occur during future heat waves, all residents should be advised to install air-conditioning systems in their homes or apartments and encouraged to use them when indoor temperatures are uncomfortably warm. Summer weather forecasts should include heat index information. During periods of extreme heat, public health advisories should be issued encouraging residents to seek shelter in air-conditioned areas and to avoid strenuous outdoor activities and prolonged sun exposure. Region-specific criteria and procedures for issuing public health advisories should be developed jointly by the National Weather Service and the US Centers for Disease Control and Prevention.

Adolescent↗
PubMed1997

Expression of INK4 inhibitors of cyclin D-dependent kinases during mouse brain development.

In situ hybridization of mouse embryo sections demonstrated expression of mRNAs encoding two polypeptide inhibitors (p18INK4c and p19INK4d) of cyclin D-dependent kinase (CDK) 4 and CDK6 in the central nervous system. No expression of two other INK4 members, p16INK4a and p15INK4b, was observed. The p19INK4d and p18INK4c proteins formed complexes with either CDK4 or CDK6 in a temporal pattern consistent with the results of in situ hybridization. Expression of INK4c was observed at embryonic day 13.5 in neuroepithelial zones of the developing brain, being restricted to dividing neuroblasts but absent from differentiating postmitotic neurons. In the neocortex, p18INK4c was expressed precisely at those developmental stages when neuroblasts switch from a symmetric to an asymmetric pattern of cell division with concomitant increases in their G1 interval. INK4d RNA was detected from embryonic day 11.5 onward, at higher levels than INK4c and with a distinctly different spatial and temporal pattern. Marked INK4d expression was seen in dorsal root ganglia, spinal cord, and focally throughout the brain, but primarily in postmitotic neurons. Neural expression of INK4d continued postnatally into adulthood in postmitotic cells of the dentate gyrus, the pyramidal layer of the hippocampus, and in discrete regions of the cerebral cortex, cerebellum, thalamus, and brainstem. Downregulation of p19INK4d in the dentate gyrus after kainic acid-induced seizures indicated that its expression could also be modified in nondividing cells by excitotoxic stress. Therefore, p19INK4d may contribute to maintaining the quiescent state, acting as a buffer to prevent reactivation of cyclin D-dependent kinases in terminally differentiated cells.

Animals↗
PubMed1997

Bleaching following porcelain veneers: clinical cases.

These clinical reports present two somewhat identical cases needing bleaching of the opposing teeth following placement of porcelain veneers. Using a new light-activated power bleaching gel (Opalescence Xtra) eliminated color discrepancies between veneered and non-veneered teeth. In both cases ideal esthetic results were achieved.

Adult↗
PubMed1996

Anorexia nervosa and steroid withdrawal.

We report a case of anorexia nervosa in a 14-year-old girl following withdrawal of oral prednisolone used in the treatment of asthma. The patient exhibited depressed affect and disturbance of body image prior to onset of anorexia. To the authors' knowledge this is the first report of anorexia nervosa precipitated by steroid withdrawal. The pathogenesis is discussed with reference to recent literature, considering both the physiological and psychological impact of steroid withdrawal.

Adolescent↗
PubMed1996

Hypoxic and excitotoxic damage to cultured rat retinal ganglion cells.

The cytotoxic effects of hypoxia and excitatory amino acids on cultured retinal ganglion cells were studied. The influence of coculture with retinal Müller glia and cortical astrocytes on cell survival was evaluated, as were the effects of the N-methyl-DL-aspartate inhibitor, MK-801. Dissociated retinal neurons from 7-day-old Sprague-Dawley rats were plated on a laminin substrate, neocortex-derived glial monolayers, or Müller cell monolayers. Ganglion cells were labeled by injection of DiI into the superior colliculus 2 days prior to dissociation. Exposure of cultured ganglion cells to glutamate and N-methyl-DL-aspartate showed a time- and concentration-dependent survival rate. Exposure of cells to hypoxia demonstrated a survival rate that was dependent on time and O2 concentration. Excitotoxic and hypoxic damage was entirely blocked by the specific non-competitive inhibitor of N-methyl-DL-aspartate, MK-801. Retinal ganglion cells cultured on cortical astrocytes and retina-derived Müller glia showed significantly better survival rates (P < 0.001) than cells cultured on laminin-coated dishes under control conditions, in hypoxia (9% to 15% O2), and after exposure to 200 microM glutamate. Retinal ganglion cells cultured on Müller glia showed significantly better survival rates (P < 0.01) than those cultured on cortical astrocytes under conditions of hypoxia (9% to 15% O2) and exposure to 200 microM glutamate. The results demonstrate that excitotoxic and hypoxic damage to cultured retinal ganglion cells is moderated by NMDA receptor blockade and by the presence of glial cells, especially retinal Müller cells. This system may provide a useful model for studying the pathophysiology of excitotoxicity and hypoxia on cultured retinal ganglion cells, and may be used to help identify potentially clinically useful therapeutic agents.

Animals↗
PubMed1996

Expression of apoptosis-regulatory genes in lung tumour cell lines: relationship to p53 expression and relevance to acquired drug resistance.

As a first step towards elucidating the potential role(s) of bcl-2 and bcl-2-related genes in lung tumorigenesis and therapeutic responsiveness, the expression of these genes has been examined in a panel of lung cancer cell lines derived from untreated and treated patients, and in cell lines selected in vitro for multidrug resistance. Bcl-2 was hyperexpressed in 15 of 16 small-cell lung cancer (SCLC) cell lines and two of five non-small-cell lung cancer (NSCLC) lines compared with normal lung and brain, and hyperexpression was not chemotherapy related. Bcl-x was hyperexpressed in the majority of SCLC and NSCLC cell lines as compared with normal tissues, and all lung tumour lines preferentially expressed bcl-x1-mRNA, the splice variant form that inhibits apoptosis. Bax gene transcripts were hyperexpressed in most SCLC and NSCLC cell lines examined compared with normal adult tissues. Mutant p53 gene expression was detected in the majority of the cell lines and no relationship between p53 gene expression and the expression of either bcl-2, bcl-x or bax was observed. No changes in bcl-2, bcl-x and bax gene expression were observed in multidrug-resistant cell lines compared with their drug-sensitive counterparts.

Adult↗
PubMed1996

Behavioural changes in people with learning disability and dementia: a descriptive study.

The behaviour of 12 people with mild and more severe learning disability and dementia is described using Past Behavioural History Inventory (PBHI), an instrument devised for the description of behaviour in people of normal intelligence and dementia. The PBHI appears sensitive to behavioural changes. The behavioural changes are described and are similar to those seen in people without a learning disability. Carers were unaware of the behavioural changes associated with dementia. The behavioural changes could be used to assist in the earlier diagnosis and management of dementia in people with learning disability.

Activities of Daily Living↗
PubMed1996

In vitro mineralization and implant calcium phosphate-hydroxyapatite crystallinity.

Biological dissolution of implant calcium phosphate coatings release local concentrations of divalent ions, which may influence mineralization. The objective of this study was to determine the effects of calcium phosphate release from coated commercially pure titanium discs using a bone-like cell culture bioassay. Sandblasted discs were prepared with or without hydroxyapatite crystallinities (50, 75, and 90 percent). Samples of each coating were randomly assigned and either preincubated for 24 hours with media or not before the addition of cells (2200/ mm2). Cultures were grown for 72 hours in culture medium containing 0.5 microCi/mL45 Ca. After rinsing, the remaining calcium phosphate surface was dissolved and counted. Three independent trials were performed. Results indicated proliferation was not altered as a function of crystallinity (P > 0.05) among any of the groups. However, a significant (P < 0.01) inverse relationship was found for biologically mediated mineralization as a function of calcium phosphate crystallinity. Low crystalline surfaces (nominally 50 percent) had the highest level of mineralization, with 75 percent crystalline surfaces being intermediate and 90 percent crystalline samples having the lowest amount of relative mineral formation. Mineralization only occurred on sandblasted commercially pure titanium upon supplementation of the growth medium with an organophosphate (beta-glycerophosphate), although this was less than on culture plastic. The results suggest calcium phosphate dissolution, as a function of implant coating crystallinity, can alter biological mineralization and may be one means in which enhanced mineral formation occurs around calcium phosphate-coated dental implants.

Analysis of Variance↗
PubMed1996

Motivational deficits after brain injury: effects of bromocriptine in 11 patients.

OBJECTIVE: To test the hypothesis that treatment with bromocriptine would ameliorate deficits in clinical motivation, responsiveness to reward, and frontal cognitive function after brain injury. METHOD: An open trial in six men and five women who had had either traumatic brain injury or subarachnoid haemorrhage between two months and five years previously. After repeated baseline assessments, bromocriptine was given in gradually increasing doses. Assessments were repeated at increasing doses, during maintenance, and after withdrawal. Novel structured instruments for quantifying motivation were developed; measures of anxiety and depression, and cognitive tests sensitive to motivation or frontal lobe involvement were also given. RESULTS: Bromocriptine treatment was followed by improved scores on all measures other than mood. Improvement was maintained after bromocriptine withdrawal in eight of the patients. CONCLUSION: Poor motivation in patients with brain injury may result from dysfunction in the mesolimbic/mesocortical dopaminergic circuitry, giving rise to associated deficiencies in reward responsiveness and frontal cognitive function.

Adult↗
PubMed1996

Food-deprivation affects seawater acclimation in tilapia: hormonal and metabolic changes

We tested the hypothesis that nutritional state affects seawater acclimation by transferring either fed or food-deprived (2 weeks) male tilapia (Oreochromis mossambicus) from fresh water to full-strength sea water. Food-deprivation resulted in a significant increase in plasma concentrations of Na+, Cl-, cortisol, glucose, total amino acid, glutamate, serine and alanine, and in hepatic pyruvate kinase (PK) and lactate dehydrogenase (LDH) activities, whereas the prolactin-188 to prolactin-177 ratio (tPRL188:tPRL177) and plasma prolactin-188 (tPRL188), lactate, arginine and hepatic glycogen content and hepatic alanine aminotransferase (AlaAT) and 3-hydroxyacyl-Coenzyme A dehydrogenase (HOAD) activities were lower than in the fed group. Seawater transfer significantly increased the tPRL188:tPRL177 ratio and plasma concentrations of Na+, Cl-, K+, growth hormone (GH), glucose, aspartate, tyrosine, alanine, methionine, phenylalanine, leucine, isoleucine and valine levels as well as gill Na+/K+-ATPase activity and hepatic PK and LDH activities, whereas plasma tPRL177, tPRL188, glycine and lysine concentrations were significantly lower than in fish retained in fresh water. There was a significant interaction between nutritional state and salinity that affected the tPRL188:tPRL177 ratio and plasma concentrations of Cl-, GH, glucose, aspartate, tyrosine, serine, alanine, glycine, arginine and hepatic PK, LDH, AlaAT, aspartate aminotransferase, glutamate dehydrogenase and HOAD activities. These results, taken together, indicate that food-deprived fish did not regulate their plasma Cl- levels, despite an enhancement of plasma hormonal and metabolic responses in sea water. Our study also suggests the possibility that plasma prolactin and essential amino acids may be playing an important role in the seawater acclimation process in tilapia.

Journal Article↗
PubMed1996

Anti-Trypanosoma cruzi antibody isotype profiles in patients with different clinical manifestations of Chagas' disease.

Chagas' disease results from infection with the protozoan hemoflagellate Trypanosoma cruzi. Patients in the chronic phase of infection can be categorized into four groups based on the presence of cardiac abnormalities (CARD), gastrointestinal involvement (DIGEST), a combination of both presentations (BOTH), or indeterminate (IND) if Chagas' related pathology is not apparent. Previous studies have indicated that parasite-specific antibody production is important in both resistance to and pathogenesis of disease. The anti-T. cruzi epimastigote stage antibody isotype profiles in the sera of Brazilian patients from each clinical category, as well as from uninfected individuals (UNINF) from the same endemic area were analyzed. Anti-epimastigote immunoglobulin G (IgG)1 and IgG3 levels were strikingly high with titers > or = 1:100,000. Sera from patients in the CARD group had higher levels of IgM than either UNINF or IND individuals, which is consistent with the theory that autoimmunity may contribute to chagasic cardiomyopathy. The IgA levels were higher in sera from patients with gastrointestinal involvement when compared with individuals from any of the other clinical categories as well as from uninfected controls. Interestingly, patients with both digestive and cardiac involvement did not express high serum levels of IgA. However, like patients with cardiac involvement alone, persons with both clinical manifestations produced elevated levels of IgG2 compared with the IND or UNINF groups. These data suggest the presence of complex immunoregulatory processes, most likely related to differential cytokine involvement, which can influence the expression of antibody isotypes and possibly the course of disease.

Adolescent↗
PubMed1996

Detection of potential cytokine gene(s) in an Alu-PCR library from the human chromosome 4.

Jumping and linking libraries have been constructed in order to have more information of chromosome 4. Two types of jumping libraries (Not I and Xma III jumping) and one linking library were prepared. The jumping clones represent DNA regions between two rare-cutting enzymes sites (such is Not I or Xma III) whereas linking clones represent only the area which surrounds the rare-cutting site. These clones were used as target DNA in Alu-PCR. The Alu-PCR fragments were cloned into pGEM-T vector and transformed into Escherichia coli JM 109 competent cells. The colonies were screened for inserts by restriction analysis. More than 50% of the colonies were shown to contain inserts. Inserts from each library were screened by PCR. One of the jumping libraries appeared to have inserts containing CpG islands and AT-rich sequences.

Chromosomes, Human, Pair 4↗
PubMed1996

State of the national's poison centers: 1995 American Association of Poison Control Centers Survey of US Poison Centers.

The American Association of Poison Control Centers (AAPCC) 1995 annual survey is summarized. A decline in the total number of poison centers was noted (from 104 in 1991 to 83 in 1995). The 83 US poison centers handled 2,431, 599 human exposure cases. Certified centers (44) served 63.1% of the US population, handled 72.5% of all poison exposures handled by poison centers nationally, and achieved higher utilization rates within their regions (10.9 vs 7.4 human exposure cases handled/1,000 population). Certified centers had superior staff credentials as measured, by passing the certification examinations for specialists in poison information or board certification for medical and managing directors. Funding for poison centers in 1995 to-total $74.6 million, although this funding level was recognized to be inadequate as only 63.1% of the population was served by certified centers and utilization of poison centers was not optimal. The annual cost of covering the entire US with adequate poison control services (meeting AAPCC certification standards and with utilization at a level of 15 human exposures per thousand population) is estimated at $120 million. Funding difficulties were prevalent. Thirty-five centers indicated that closure had been a real threat at least once in the previous 5 years. Analysis of cost per human exposure case by center volume demonstrated that economies of scale were achieved when a center handled at least 20,000 to 30,000 human exposure calls/year. Increasing human exposure volume beyond 30,000/year did not lead to a reduction in the average cost per human exposure case.

Cost-Benefit Analysis↗