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Biomedical subjects

J Sheridan

Publications and source records attributed to J Sheridan.

65 records · Page 4Linked to original sources
PubMed1974

Gap junction formation between reaggregated Novikoff hepatoma cells.

We have combined freeze-fracture and electrophysiological methods in a study of gap junction formation between reaggregated Novikoff hepatoma cells. Cell clumps are dissociated with EDTA, and the resulting single cells are allowed to reaggregate (5-180 min) in loose pellets in the presence of calcium at 37 degrees . The earliest electron microscopic evidence for the genesis of new junctions is the appearance of flattened regions of the plasma membrane with a relative paucity of small intramembranous particles. These regions contain instead loosely organized groupings of 9- to 11-nm intramembranous particles, which are seen on the A face of the fractured plasma membrane, while corresponding pits occur on the membrane B face. We have termed the specialized membrane regions "formation plaques." They are seen as early as 5 min after reaggregation and are quite numerous by 30 min. Larger plaques are observed at later times. Plaques seen at 30 min are consistently matched with other plaques on apposed cells, although the extracellular space separating these structures still exceeds 10 nm. By 60 min, some matched plaques display a reduced extracellular space, resembling that of normal gap junctions. Between 30 and 60 min, aggregates of closely packed particles on A faces and hexagonally arranged pits on B faces frequently appear in the formation plaques. The aggregates, which are indistinguishable from small gap junctions, appear to enlarge over the subsequent 2-hr period as the number of unaggregated 9- to 11-nm particles declines. Microelectrode studies demonstrate progressive increases in the percent of interfaces containing lowresistance junctions and in the degree of elctrical coupling in preparations incubated up to 2 hr. Coupling is first detected at about the same time as particle aggregates (or formation plaques with reduced extracellular spaces), and increases as aggregate sizes increase.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Chronic stress modulates the immune response to a pneumococcal pneumonia vaccine.

OBJECTIVE: Influenza and pneumonia account for significant morbidity and mortality, particularly in older individuals. Previous studies have shown that spousal caregivers of patients with dementia have poorer antibody and virus specific T cell responses to an influenza virus vaccine relative to noncaregiving control subjects. This study tested the hypothesis that stress can also significantly inhibit the IgG antibody response to a pneumococcal bacterial vaccine. METHOD: We measured antibody titers of current caregivers, former caregivers, and control subjects after vaccination with a pneumococcal bacterial vaccine. RESULTS: Caregivers showed deficits relative to controls and former caregivers in their antibody responses to vaccination. Although the groups did not differ before vaccination or in the rise in antibody 2 weeks or 1 month after vaccination, current caregivers had lower antibody titers 3 and 6 months after vaccination than either former caregivers or controls. CONCLUSIONS: These data, the first evidence that chronic stress can inhibit the stability of the IgG antibody response to a bacterial vaccine for pneumonia, provide additional evidence of health risks associated with dementia caregiving.

Alzheimer Disease↗
PubMedDate not supplied

Sporting life.

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Adult↗
PubMedDate not supplied

Congenital vertical talus and its familial occurrence: an analysis of 36 patients.

Thirty-six patients (57 feet) showing congenital vertical talus were treated at the St. Louis Unit of the Shriners Hospital between 1958 and 1978. A high incidence of congenital hip dislocatiom, arthrogryposis, congenital hypoplasia of tibia and CNA disorders was noted as associated abnormalities. These patients are classified in 3 groups: (I) primary isolated form (16 patients); (II) associated form without neurological deficit (12 patients); (III) associated form with neurological deficit (8 patients). Fifty per cent of the patients with primary isolated form had positive family history of foot deformities in their first degree relatives. Familial incidence of congenital vertical talus was observed in 2 families studied. Genetic factors may play an important role in the etiology of the primary isolated form of congenital vertical talus. The current treatment is a one-stage open reduction of the talonavicular dislocation, combined with a posterior release. A subtalar bone block is often imperative to maintain correction. Cast correction alone has never succeeded as the definitive treatment of this condition.

Female↗
PubMedDate not supplied

Orthodontic headgear to control hemorrhage.

Oral hemorrhage can be a serious problem for hemophiliacs. This case history describes the use of topical medicaments to control oral hemorrhage. Further, the maintenance of pressure over the bleeding site using an orthodontic variable pull headgear is described. In spite of the patient's age (seventeen months), the appliance was effective in stopping the hemorrhage and was well tolerated.

Adolescent↗