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Biomedical subjects

L O'Connell

Publications and source records attributed to L O'Connell.

8 recordsLinked to original sources
PubMed1991

X-ray structure of human relaxin at 1.5 A. Comparison to insulin and implications for receptor binding determinants.

The X-ray crystal structure of relaxin at 1.5 A resolution is reported for the physiologically active form of the human hormone. Relaxin is a small, two-chain polypeptide that is a member of the protein hormone family that also includes insulin and the insulin-like growth factors IGF-I and IGF-II. These hormones have biologically diverse activities but are structurally similar, sharing a distinctive pattern of cysteine and glycine residues. The predicted structural homology of relaxin to insulin is confirmed by this structural analysis; however, there are significant differences in the terminal regions of the b-chain. Although relaxin, like insulin, crystallizes as a dimer, the orientation of the molecules in the respective dimers is completely different. The region of the relaxin molecule proposed to be involved in receptor binding is part of the dimer interface, suggesting that some of the other residues contained in the dimer contact surface might be receptor binding determinants as well. The proposed receptor binding determinants for insulin likewise include residues at its dimer interface. However, because the dimer contacts of relaxin and insulin are quite different, it appears that these two structurally related hormones have evolved somewhat dissimilar mechanisms for receptor binding.

Amino Acid Sequence↗
PubMed1991

Conditions not attributable to a mental disorder: an epidemiological study of family problems.

OBJECTIVE: The objective of this research was to identify and measure the differences among three groups of psychiatric outpatients: those with family problems but without mental disorders, those with both family problems and mental disorders, and those with a mental disorder but without family problems. DSM-III V code conditions (conditions not attributable to a mental disorder) other than family problems do occur, but family problems were chosen because of their importance. METHOD: All patients admitted to an outpatient psychiatric clinic during a 2-year period were studied (N = 382). Of these, 92 had V code conditions unrelated to family problems and were excluded. Data are presented on the remaining 290 patients. Sociodemographic variables, DSM-III diagnoses, source of referral, previous and subsequent use of outpatient services, and type of family problem were examined. Patients were from a low-income population and came from three ethnic groups (white, black, and Hispanic). RESULTS: Among whites, more men than women had family problems without mental disorders; among blacks, more women than men had family problems with and without mental disorders. Marital problems occurred most frequently in the group with family problems without mental disorders, and married subjects were more likely to have a V code condition. Professional referrals were more common than other referral sources in all three groups. However, family problems without mental disorders were more likely to occur among those who were referred by their families and had never had psychiatric treatment; patients with family problems and mental disorders were more likely to be self-referred and to have been previously treated; those with a mental disorder but without family problems were usually referred by professionals and almost always had been previously treated. There appeared to be underreporting of family problems among those with family problems and mental disorders and among black men with family problems with and without mental disorders. CONCLUSIONS: More research is needed on the patterns of use of outpatient psychiatric services by individuals with family problems and other V code conditions.

Adult↗
PubMed1985

Effect of gamma-irradiation on the healing of gastric biopsy sites in monkeys. An experimental model for peptic ulcer disease and gastric protection.

The acute effects of gamma-irradiation on the gastric mucosa have been studied in a primate model. Fiberoptic gastroscopies were performed in 6 rhesus monkeys in the basal state as well as 3 h and 3, 7, and 9 days after total body irradiation (800 rads). Gastric biopsy specimens (diameter 1 mm) obtained during each session were examined using light microscopy and scanning electron microscopy; in addition, subsequent healing of the biopsy sites was assessed visually. Gastric biopsy sites were completely healed in 3 days in the basal state; in contrast, ulcer craters (diameter 1 mm) were still present at the site of the biopsies 3, 7, and 9 days after the biopsies were performed in irradiated animals. Light microscopic examination of the biopsy specimens demonstrated only lymphocytic infiltration of the lamina propria. In contrast, scanning electron microscopic examination revealed that the size and number of microvilli of the gastric surface epithelial cells were increased on the day of irradiation compared to basal; 3-9 days later, numerous gastric surface epithelial cells were damaged or had disappeared so that bare areas of the lamina propria were visible in the specimens taken outside of the ulcer craters. These changes may reflect inadequate protection of insufficient regeneration of gastric mucosal cells which, in turn, would explain the persistence of ulcers after gastric biopsies were performed in irradiated monkeys.

Animals↗
PubMed1978

IQ following treatment of lead poisoning: a patient-sibling comparison.

Forty-seven children treated for lead poisoning (PbB 50 to 365 microgram/dl) were compared to siblings next in age (PbB less than 40 microgram/dl) by a battery of psychologic tests. Symptoms were present in 18 but none had frank encephalopathy. Physical and neurologic examinations revealed no residual damage. Mean psychologic test scores showed no significant difference between patients and controls except in the arithmetic subtest, in which patients' scores were not related to lead concentration. Intelligence tests failed to distinguish children successfully treated from their sibling controls.

Child↗
PubMed1977

Cold agglutinins in a case of chronic lymphatic leukaemia. A study of the lymphocyte surface.

A case of chronic lymphatic leukaemia with cold agglutinins is presented in which peripheral blood lymphocytes of varying maturity appeared to possess T- and B-cell markers. A cold agglutinin IgM in type is identified in the serum and at the cell surface. This seems to be responsible for the spontaneous rosetting of sheep red blood cells (SRBC); A single clonal origin of these cells is suggested with maturation arrest. It is also suggested that with configurational change in lymphocyte surface cryoglobulins may sometimes produce spontaneous rosetting with SRBC.

Agglutinins↗
PubMedDate not supplied

Gauging pesticide exposure of handlers (mixer/loaders/applicators) and harvesters in California agriculture.

Agricultural workers acquire pesticide exposures as a function of the properties of the product, crop, and work task. Mixer/Loaders and Applicators have greater exposure potential than other workers since concentrated formulations are handled during preparation and application of spray mixes. Exposures can be estimated using passive dosimetry and biological monitoring. Measured exposures are invariably less than estimates derived from surrogate data due to a series of conservative "worst case" assumptions and exposure estimates derived from small portions of the work day. Data have also been collected to estimate the exposure potentials of harvesters. We are establishing a set of empirical transfer factors (cm2/h) that can be used to estimate daily harvester exposure (transfer factor x dislodgeable foliar residue x hours). These estimates are important to current efforts to establish exposure-based reentry intervals to protect against acute and chronic toxicity.

Agriculture↗