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Biomedical subjects

S McConnell

Publications and source records attributed to S McConnell.

At least 37 records · Page 2Linked to original sources
PubMed1993

Histological, histochemical and ultrastructural features of hyaline inclusions in hepatocytes of striped dolphins (Stenella coeruleoalba).

Many striped dolphins (Stenella coeruleoalba) which died in the recent morbillivirus epizootic in the Mediterranean Sea had hyaline inclusions in hepatocytes. We investigated the histological, histochemical and ultrastructural features of these inclusions in two affected dolphins. Histochemical tests indicated that they contained glycoprotein but not lipid. Ultrastructurally, they consisted of granular, moderately electron-dense material, bounded by a membrane. A central or eccentric core of highly electron-dense material was usually apparent. The inclusions were probably of lysosomal origin.

Animal Diseases↗
PubMed1993

Circumvention of maternal antibody interference by immunization of newborn pigs with glycoprotein gIII-deleted marker vaccine.

Maternal antibodies interfere with the immunization of swine by modified live-virus pseudorabies virus (PRV) vaccines. To test the hypothesis that a PRV vaccine attenuated by deletions in the thymidine kinase (TK) and gIII genes might reduce interference by maternal antibodies, pigs with moderate to low levels of colostral PRV antibodies were immunized with the TK- gIII-OMNIMARK-PRV vaccine. Vaccinates and non-vaccinates were challenged intranasally with virulent PRV at 7 weeks of age. In support of the hypothesis, it was found that central nervous system (CNS) and/or respiratory disease developed in six out of 10 controls with a fatal outcome in one, while two out of 13 vaccinates showed only very mild and transient CNS or respiratory disease signs with no fatalities. All vaccinates gained weight while non-vaccinates initally lost weight. At post-challenge day (PCD) 11, vaccinates showed 4.5 lb/pig greater weight gain than non-vaccinates. Virus neutralization (VN) analyses before and after challenge showed that vaccinates had been primed immunologically. In another experiment, newborn pigs from a pseudorabies disease-quarantined herd with high VN antibody titres were vaccinated, respectively, with the gIII-TK-OMNIMARK-PRV vaccine, a TK-gI-gX-vaccine, or no vaccine and challenged with virulent PRV at 14 weeks of age when VN titres were < 1:2. By PCD 9, the TK-gIII-group had outgained the TK-gI-gX- and the control groups, respectively, by 6.0 and 3.2 lb per pig.

Animals↗
PubMed1992

Age-related changes in binding to excitatory amino acid uptake sites in human cerebellum.

In vitro autoradiography and test-tube assay of the sodium-dependent binding of D-[3H]aspartate were used to localize and quantify the uptake site for the excitatory amino acid neurotransmitters glutamate and aspartate in the cerebellar cortex of human cerebellar hemispheres. Autoradiograms revealed a pronounced heterogeneity in the distribution of D-[3H]aspartate binding in cortex from adult brains, with the highest binding density corresponding to the Purkinje cell layer, high binding in molecular layer and low binding in granule cell layer. In contrast, cerebellar cortex from infants at term (40 weeks gestation) had only low binding of the ligand in both the molecular and the Purkinje cell layers. Both methods employed for measuring D-[3H]aspartate binding showed that the number of binding sites in Purkinje and molecular layers increased rapidly from term to 20 weeks postnatal age and achieved levels higher than those found in adult cerebellum. It is concluded that a substantial increase in the numbers of glutamate/aspartate uptake sites takes place in the human cerebellum during the early postnatal period. It is deduced that the excess uptake sites are eliminated as the cerebellum matures.

Aged↗
PubMed1992

Age-related changes in binding to excitatory amino acid uptake site in temporal cortex of human brain.

The binding of D-[3H]aspartate to the specific uptake site for the excitatory amino acids glutamate and aspartate was measured in homogenates of temporal lobe cortex taken at postmortem from 76 human infant and adult brains. Binding levels were very low in brains of preterm and term infants but increased rapidly during the first 20 postnatal weeks to reach levels which exceeded those in adult brains. Linear regression analysis which compared the amount of D-[3H]aspartate binding with the age of the infant, showed a positive correlation up to 25 postnatal weeks. Saturation analysis showed that the maximum number of D-[3H]aspartate binding sites (Bmax) in temporal cortex from infants aged 20 postnatal weeks was 3 times greater than the number of sites in adult brain. The findings show that the number of excitatory amino acid uptake sites, which may be associated in part with presynaptic terminals, increase in number rapidly after birth. Furthermore, the data may indicate that a slow regression of excitatory amino acid terminals occurs during the later stages of brain development.

Aging↗
PubMed1992

Health care for all: comparing proposals for reform. A roundtable discussion: Part 2.

Part 1 of this roundtable discussion [Geriatrics 1992; 47(Sept):34-48] examined the flaws in our current healthcare system and factors that are interfering with our nation's ability to achieve reforms. This month, the panelists discuss the benefits and drawbacks of the major healthcare reform proposals, including managed care, single-payer systems, and so-called "play or pay." The practical aspects of any redistribution of healthcare resources are considered as each panelist outlines a favored approach. The influence of special interests, such as the insurance industry, is also discussed.

Health Policy↗
PubMed1992

Health care for all: long-term care, the missing piece. A roundtable discussion: Part 3.

Long-term care has been described as the "missing piece" in many healthcare reform proposals. Yet the cost of nursing home care often exceeds that of acute care, especially for the elderly with Alzheimer's disease. In this final installment of a three-part roundtable discussion, panelists discuss the options for providing long-term care, such as social insurance, a single-payer system, play or pay, or private insurance models. Alternatives to nursing home care, such as community service centers and home care, are discussed. The panelists conclude with an examination of how these proposed reforms might affect the practices of physicians and the U.S. economy.

Community Health Services↗
PubMed1991

Ultrastructural features of alveolar lesions in induced respiratory syncytial virus pneumonia of calves.

Ultrastructural changes occurred in alveolar epithelium in the acute and repair stages of induced respiratory syncytial virus pneumonia induced in eight calves (calf Nos. 1-7, 3 to 6 days old and calf No. 8, 2 weeks old), using a bovine strain of respiratory syncytial virus. Five of the calves were Friesians, three were Hereford x Friesians, and all were male. Tissues from three mock-infected control calves (two Friesian, one Hereford x Friesian) were also examined. Evidence of respiratory syncytial virus infection was observed in both type I and type II pneumocytes from day 4 to day 8 after infection. Infection of type I pneumocytes frequently resulted in necrosis. The response of type II pneumocytes to respiratory syncytial virus infection varied and included hypertrophy, hyperplasia, and syncytial formation. In some infected type II pneumocytes, there were numerous irregular projections of the cell surface, associated with viral budding. Hypertrophy and hyperplasia of type II pneumocytes, epithelial syncytium formation, and irregular cytoplasmic projections from epithelial cells caused considerable thickening of respiratory membrane and occlusion of alveolar lumina. Neutrophils were frequently observed in close association with virus-infected epithelial cells, but evidence of respiratory syncytial virus infection and replication was not observed in alveolar macrophages or neutrophils. Proliferation of type II pneumocytes appeared to play a major role in maintaining the integrity of the alveolar epithelium during the acute stage of the experimental pneumonia. Increased numbers of type II pneumocytes were present on alveolar walls, particularly from 4 to 8 days after infection, and some alveoli were lined entirely by this cell type. In some areas, however, squamous epithelial cells were also involved in covering exposed alveolar basement membrane.

Animals↗
PubMed1991

Ultrastructural features of lesions in bronchiolar epithelium in induced respiratory syncytial virus pneumonia of calves.

Ultrastructural changes were observed in bronchioles in acute and repair stages of respiratory syncytial virus pneumonia induced in eight young calves (calf Nos. 1-8) using a bovine strain of respiratory syncytial virus. Five of the calves were Friesians and three were Hereford x Friesians and all were male. Tissues from three mock-infected control calves (two Friesian, one Hereford x Friesian) were also examined. Calves were from 3 to 6 days old at the time of first inoculation, with the exception of calf No. 8, which was 2 weeks old. In the acute stage of the induced pneumonia, evidence of respiratory syncytial virus replication and release was demonstrable in both ciliated and non-ciliated bronchiolar epithelial cells, with the virus-releasing process most obvious at 4 and 5 days after infection. Respiratory syncytial virus infection of bronchiolar epithelium was associated with various changes, including hypertrophy, hyperplasia, and formation of syncytia. Necrosis of epithelial cell structures usually appeared to be preceded by their desquamation from bronchiolar walls. Respiratory syncytial virus infection resulted in considerable damage to the bronchiolar ciliary apparatus. Such damage was seen as early as 1 day post-infection and was still obvious at 10 days post-infection. Neutrophils were closely associated with respiratory syncytial virus infected epithelial cells and evidence of neutrophil fusion with infected epithelial cells was seen. These observations suggest that neutrophils may be involved in killing respiratory syncytial virus infected cells and that neutrophils might play an important role in early antiviral defense against respiratory syncytial virus at a time when antibody levels are low and other cellular defenses are not fully in play. Bronchiolar repair was evident from 6 days after infection and was well advanced at 10 and 13 days after infection.

Aged↗
PubMed1990

Safety and efficacy of a thymidine kinase negative equine herpesvirus-1 vaccine in young horses.

A drug induced equine herpesvirus-1 (EHV-1) mutant lacking thymidine kinase inducing activity was developed and evaluated as a vaccine. The safety and effectiveness of the vaccine to protect against experimentally induced EHV-1 respiratory disease were evaluated in weanling horses free of EHV-1 neutralizing antibody. The vaccine was safe when administered either intramuscularly or intravenously, and EHV-1 was not shed intranasally during the 12 days following administration. Intranasal challenge with virulent EHV-1 was used to evaluate vaccine efficacy. Following challenge, there was a significantly (p less than 0.05) greater increase in peak body temperatures and duration of nasal virus shedding in the nonvaccinates, and a significant (p less than 0.05) increase in serum neutralizing antibody titers in the vaccinates.

Animals↗
PubMed1990

Myocardial dysfunction during percutaneous transluminal coronary angioplasty.

Balloon inflation during percutaneous transluminal coronary angioplasty (PTCA) transiently occludes the coronary artery, causing temporary ischemia. In patients without collaterals, regional hypokinesis of the ventricular myocardium at risk occurs within the first 20 seconds and persists throughout balloon inflation. Early PTCA procedures were performed with brief balloon inflations, but the desire to improve procedural results has led many operators to extend balloon inflation times to 45 seconds or longer. Although the ischemic indicators of pain and electrocardiographic changes are commonly noted with these longer inflations, actual hemodynamic consequences are often obscured by physiological compensation. The PTCA-induced ischemic period is often too short to measure changes in cardiac output by conventional methods, but it is increasingly evident that profound regional myocardial dysfunction, in fact, occurs. Continuous two-dimensional echocardiography with quantitative assessment of regional wall motion and ejection fraction is particularly effective in detecting the location, extent, and temporal change of ischemic regional contractile dysfunction. Echocardiographic recordings during baseline, ischemia, and post-balloon-deflation periods permit examination of PTCA-caused alterations in ejection fraction and ventricular volumes and allow the use of testing techniques aimed at mitigation of ischemia.

Adult↗
PubMed1989

Molecular confirmation of an abortigenic strain of equine herpesvirus 1 (subtype 1) in a pregnant mare study.

Four pregnant mares were inoculated intranasally and/or intravenously with equine herpesvirus 1 (EHV-1), subtype 1 during the third trimester of gestation. One mare aborted on postinfection day 15, one mare delivered a sick, weak full term foal, and two mares delivered healthy, full term foals. EHV-1, subtype 1 was isolated from several tissues of the aborted fetus and from the thymus of the sick foal. DNA restriction endonuclease patterns of the recovered EHV-1 viruses were identical to those of the EHV-1 challenge strain, documenting the origin of the abortigenic viruses.

Abortion, Veterinary↗
PubMed1989

Doing well with AIDS: three case illustrations.

This report focuses on the abilities of three people diagnosed with acquired immune deficiency syndrome (AIDS) to maximize their state of well-being. The purpose of this ongoing investigation is to identify factors that may help enhance AIDS patients' states of well-being, ultimately achieving the provision of holistic and life-giving nursing care. A naturalistic approach was used to generate an understanding of the concept, "doing well." Five themes regarding "doing well" with AIDS emerged from the interview data. These themes include: autonomy/mastery over the disease; existential/spiritual journey toward understanding; self-acceptance; staying active and involved; and positive thinking. Nursing implications of these themes are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Isolations of Cache Valley virus in Texas, 1981.

Two strains of the same virus (isolates AR 168 and 7856), were isolated in 1981 from an apparently healthy cow and a sick sheep in TX, U.S.A. These isolates were shown to be members of the Bunyamwera serogroup (family Bunyaviridae, genus Bunyavirus) by complement-fixation tests. Serum dilution-plaque reduction neutralization test results indicated that the isolates are closely related to Cache Valley virus. The virus isolates were characterized by sensitivity to lipid solvent, size (50-100 nm by filtration and 70 nm by electron microscopy), heat (56 degrees C) and pH 3 lability, cytopathic effects or plaques in cultures of Vero, LLC-MK2, embryonic bovine testicle and PS cells, and pathogenicity for suckling and weaned mice by the intracranial but not the intraperitoneal route. Gnotobiotic and conventional sheep and goats were experimentally infected by inoculation with one of the isolates given either intravenously or intraperitoneally. Elevation of body temperature, depression, tremors, muscle spasms, disorientation, feeding anomalies, convulsions, or other signs of central nervous system disturbances were observed.

Animals↗