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Biomedical subjects

J M Hall

Publications and source records attributed to J M Hall.

At least 127 records · Page 7Linked to original sources

Peptidase activity as a determinant of agonist potencies in some smooth muscle preparations.

The influence of degradation by peptidases on concentration-response relationships for peptide agonists of the tachykinin and bombesin-like families was investigated. The combined presence of three peptidase inhibitors, phosphoramidon (1 microM), captopril (1 microM) and bestatin (100 microM), had no significant effect on the onset rates or peak contractile responses to these peptides in the rat urinary bladder and guinea-pig taenia caeci preparations, or on their peak potentiation of the contractile response to field-stimulation in the guinea-pig vas deferens preparation. However, rates of offset of the response to tachykinins were markedly prolonged in tissues treated with peptidase inhibitors. In experiments designed to estimate clearance of applied peptide from the organ bath, there was an initial rate of loss with the guinea-pig vas deferens and taenia caeci which, measured over the first 5 min, had a half-time of 2-3 min which was then prolonged to 6-8 min in the presence of peptidase inhibitors. These results show that although peptide breakdown can be demonstrated in these systems, it seems not to be an important determinant of relative pharmacological activity measured in terms of peak response.

Animals↗

Genetic and environmental influences on cord blood serum IgE and on atopic sensitisation in infancy.

It has recently been reported that cord blood serum IgE (CBsIgE) concentrations in a black Third-World cohort were significantly higher than those in a similar cohort of white and coloured newborns, and were not influenced by an atopic family history (aFH). This study reports on the 1-year follow-up of these newborns carried out to determine whether statistical differences in median CBsIgE values at birth could be found between infants in each ethnic group who subsequently developed clinical atopy in the first year of life and those who remained healthy. The infants were seen at 3, 7 and 12 months of age. At each visit a detailed history was taken from the mothers, the infants were examined clinically for the presence of atopic disease and blood was taken for immunological assay (total serum IgE by paper-disc radio-immunosorbent testing, and radio-allergosorbent testing for egg-white, cow's milk and Dermatophygoides pteronyssinus). A combination of clinical and immunological variables was assessed in order to categorise the infants into 'atopic' or 'not atopic' groups at the end of the 1-year follow-up period. The black infants who completed the study had the lowest incidence of aFH (16%), but 64% of them developed atopic disease during infancy. The median CBsIgE values for the black infants who became atopic were lower than, but not statistically different from, those for the group who remained non-atopic (P = 0.57). The white and coloured infants who completed the study had 81.6% and 30.4% incidences of aFH respectively, with 47.4% and 58.7% respectively developing atopic disease during infancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Black People↗

Rare HRAS alleles and susceptibility to human breast cancer.

The suggestion that inherited rare alleles at the HRAS oncogene locus might be associated with susceptibility to breast cancer led us to test linkage of HRAS and the neighboring region of 11p15 to breast cancer susceptibility in 12 high-risk families. Linkage could be excluded within 17 cM of HRAS; the lod score for close linkage to HRAS was -19.9. In addition, rare HRAS alleles segregated independently of breast cancer in 8 families in which both occurred. Among unrelated breast cancer patients not selected for family history, rare HRAS alleles were slightly, but not significantly, more frequent than among controls (0.11 vs 0.04, P = 0.11). The HRAS region of 11p is not the site of a primary alteration leading to breast cancer.

Alleles↗

Alcoholism in lesbians: developmental, symbolic interactionist, and critical perspectives.

Alcoholism is a significant health concern for lesbian women, with an incidence rate perhaps three times that of the general population. The relationships among the development of alcoholism in women, the experience of stigmatization, and the complex facets of lesbian identity and lesbian community are explored. This exploration provides for a more comprehensive and critical analysis of alcoholism in lesbians. As a phenomenon of women's health, alcoholism is examined using the perspectives of developmental theory, symbolic interactionism, and critical theory. The author offers insights and implications for health care, research, and theory building.

Alcoholism↗

Mechanism of action of substance P in guinea-pig ileum longitudinal smooth muscle: a re-evaluation.

1. A proposed mechanism of contractile action of substance P in guinea-pig ileum longitudinal smooth muscle involving a decrease in membrane K+ permeability (PK) has been re-examined. 2. Potentiation of responses to substance P by the K+ channel blocker tetraethylammonium (TEA) was originally proposed as evidence for a mechanism of action of substance P involving a decrease in PK. Potentiation was confirmed; however this was found not to be specific to substance P since a similar potentiation of responses was seen with agonists not thought to act via a decrease in PK. 3. Antagonism of contractile responses to substance P by noradrenaline was similarly confirmed. However, this antagonism was found to represent a non-specific functional interaction through the inhibitory actions of beta-adrenoceptors rather than the proposed specific interaction with an increase in PK by noradrenaline which is normally alpha 1-adrenoceptor mediated. 4. Experiments were made measuring 86Rb efflux, in depolarized guinea-pig ileum longitudinal smooth muscle, to estimate PK. These studies confirmed a reported decrease in PK with TEA, but failed to detect the previously reported decrease with substance P. 5. These results, although not disproving a suggested mechanism of direct contractile action of substance P in guinea-pig ileum longitudinal smooth muscle involving a decrease in PK, do throw doubt on either the evidence, or its interpretation, as proposed by the original authors in support of such a mechanism.

Animals↗

Postoperative pain control with a continuous infusion of epidural sufentanil in the intensive care unit: a comparison with epidural morphine.

A prospective, randomized, double-blind trial was conducted to compare the analgesic actions and side effects of sufentanil continuously infused (5 micrograms/h) into the lumbar epidural space (L2-3) with those of an infusion of lumbar epidural morphine (0.5 mg/h). Forty patients admitted to an intensive care unit after elective major abdominal surgery participated over a varying period of 24-40 h. Post-operative pain was treated with an epidural bolus of either sufentanil (50 micrograms) or morphine (5 mg), followed by a continuous infusion of the same opiate. The quality of pain relief was similar in each group. The sufentanil group had a more rapid onset of analgesia. The incidence of nausea and vomiting, pruritus, and drowsiness was similar in the two groups. In spontaneously breathing patients there were no respiratory complications requiring treatment. Forced vital capacities were statistically significantly better during the first 1-4 h with sufentanil.

Adult↗

Paradental cysts on mandibular first molars in children: report of five cases.

Five cases of paradental cyst are reported which were found to arise buccal to a mandibular first permanent molar in children under the age of 10 years. The justification for calling these lesions paradental cysts is discussed. Since the histopathological findings of this lesion are non-specific, the clinical and radiographic features are of prime importance in diagnosis when the lesion occurs in this site in patients of this age. Buccal swelling adjacent to a mandibular first molar which is partially erupted or which has a soft tissue cover is a common clinical finding. Occlusal projections generally give the best presurgical diagnostic information, demonstrating the presence of a radiolucent lesion with a periosteal bone reaction buccal to the involved tooth and displacement of the roots to the lingual. The cyst can be successfully treated by simple enucleation without disturbing the associated tooth.

Child↗

Alcoholism recovery in lesbian women: a theory in development.

Utilizing the modified practice-theory strategy for theory building, a provisional theoretical model was developed to describe alcoholism recovery in lesbian women. Assumptions are acknowledged, key concepts are identified, and propositions are formulated for the purpose of generating nursing knowledge about a significant health problem in this aggregate of women. The theory's implications for nursing research, practice, and further theory development are discussed.

Alcoholism↗

Exclusion of the retinoblastoma gene and chromosome 13q as the site of a primary lesion for human breast cancer.

Chromosome 13q has been suggested as the site of a gene predisposing to human breast cancer, because loss of heterozygosity of alleles on this chromosome has been observed in some ductal breast tumors and because two breast cancer lines are altered at the retinoblastoma gene (RB1) at 13q14. To test this possibility, linkage of breast cancer susceptibility to 14 loci on chromosome 13q loci was assessed in extended families in which breast cancer is apparently inherited as an autosomal dominant trait. RB1 was excluded as the site of a breast cancer gene by a lod score of Z = -7.60 at close linkage for 13 families. Multipoint analysis yielded negative lod scores throughout the region between 13q12 and 13q34; over most of this distance, Z less than -2.0. Therefore, chromosome 13q appears to be excluded as the site of primary lesion for breast cancer in these families. In addition, comparison of tumor versus normal tissues of nonfamilial breast cancer patients revealed an alteration at the 5' end of RB1 in a mucoid carcinoma but no alterations of RB1 in five informative ductal adenocarcinomas. Linkage data and comparisons of tumor and normal tissues suggest that changes in the RBI locus either are secondary alterations associated with progression of some tumors or occur by chance.

Breast Neoplasms↗

Oxytocin infusion during second stage of labour in primiparous women using epidural analgesia: a randomised double blind placebo controlled trial.

OBJECTIVE: To determine whether the high rate of forceps delivery associated with the use of epidural analgesia could be reduced through giving an intravenous infusion of oxytocin during the second stage of labour. DESIGN: A randomised, double blind, placebo controlled trial. SETTING: Delivery suites in three hospitals. SUBJECTS: 226 Primiparous women with adequate epidural analgesia in whom full dilatation of the cervix had been achieved without prior stimulation with oxytocin. INTERVENTION: An infusion of oxytocin or placebo starting at the diagnosis of full cervical dilatation at an initial dose rate of 2 mU/min increasing to a maximum of 16 mU/min. MAIN OUTCOME MEASURES: The outcome of labour was assessed in terms of the duration of the second stage, mode of delivery, fetal condition at birth, postpartum blood loss, and the incidence of perineal trauma. RESULTS: Treatment with oxytocin was associated with a shorter second stage (p = 0.01), a reduction in the number of non-rotational forceps deliveries (p = 0.03), and less perineal trauma (p = 0.03) but was not associated with any reduction in the number of rotational forceps deliveries performed for malposition of the occiput. No adverse effects on fetal condition at birth or in the early puerperium were seen in association with the use of oxytocin. CONCLUSIONS: The use of an oxytocin infusion may reduce the high rate of operative delivery associated with epidural analgesia provided that the fetal occiput is in an anterior position at the onset of the second stage of labour but within the dose range studied does not seem to correct malposition of the fetal occiput.

Adolescent↗

Oncogenes and human breast cancer.

The role of oncogenes in breast tumorigenesis is unclear. Alterations and/or amplification of several oncogene sequences have been observed in primary human breast tumors, in breast tumor cell lines, and in mammary tumors in model systems. In principle, such alterations could be sites of primary lesions for human breast cancer, causes of tumor progression or metastasis, or simply secondary lesions of highly aberrant tumor genomes. The present study tested genetic linkage of breast cancer susceptibility to nine oncogenes in 12 extended families including 87 affected individuals. Lod scores for close linkage of each candidate sequence to breast cancer were -19.6 for HRAS, -12.3 for KRAS2, -1.0 for NRAS, -6.0 for MYC, -6.1 for MYB, -8.2 for ERBA2, -7.9 for INT2, and -5.1 for RAF1. Regions of chromosome 11p associated with tumor homozygosity and the region of 3p carrying the gene for Von Hippel-Lindau disease could also be excluded from linkage to human breast cancer. The 5-kb allele of the MOS oncogene, previously proposed to be associated with breast cancer, was absent in these families, suggesting that polymorphism at this locus is not associated with inherited susceptibility. These results strongly suggest that oncogenes are not the sites of primary alterations leading to breast cancer. On the other hand, alterations in one or more of these sequences may be associated with tumor progression.

Breast Neoplasms↗

IgG and IgA antibody in tears of rabbits immunized by topical application of ovalbumin.

Rabbits were immunized by daily topical conjunctival application of ovalbumin. Control rabbits received ovalbumin intravitreally or intravenously. The direct plaque assay was used to detect IgM antibody-producing cells in lymph node, conjunctival, lacrimal gland and Peyer's patch tissues. A culture ELISA test was used to detect IgG and IgA antibody-producing cells. Serum and tears were tested for IgG antibody by ELISA and passive hemagglutination tests, and for IgA antibody by an ELISA assay. The conjunctival and cervical lymph node cells of topically immunized rabbits produced IgG and IgM antibodies. Neither IgG nor IgM antibody-producing cells were found in the Peyer's patches or lacrimal glands. Serum IgG antibody was detected by both ELISA and HA tests. IgG antibody was found (by the ELISA assay) in tears collected from most topically immunized rabbits, and from some intravitreally immunized rabbits, but not from the intravenously immunized animals. IgA antibody was found in tear samples collected after several weeks of daily topical immunization. IgA antibody-producing cells were detected in the conjunctival tissues, but not in the lymph nodes of those rabbits.

Administration, Topical↗

The influence of ethnicity, an atopic family history, and maternal ascariasis on cord blood serum IgE concentrations.

Raised concentrations of cord blood serum (CBs) IgE have previously been demonstrated to reflect a hereditary predisposition for atopy in First World, predominantly white populations. A cross-sectional study of 53 black, 52 white, and 58 mixed race newborn infants and maternal pairs was performed in a multiethnic, mixed First and Third World society. The CBs IgE concentrations were measured with a modification of the standard IgE PRIST, which could reliably determine IgE concentrations to an accuracy of 0.01 kU/L. The black group had the highest geometric mean and median CBs IgE concentrations (0.21; 0.16 kU/L), followed by the white group (0.12; 0.12 kU/L) and the mixed group (0.10; 0.08 kU/L). If those newborn infants with an atopic family history and maternal ascariasis were excluded, the remainder had geometric mean and median CBs IgE concentrations of 0.20; 0.16 kU/L in the black subgroup, followed by values of 0.06; 0.05 kU/L in the mixed subgroup, and 0.05; 0.07 kU/L in the white subgroup. Statistically significant ethnic differences in the median CBs IgE concentrations of these subgroups were demonstrated between the black-white (p less than 0.05) and the black-mixed (p less than 0.005) ethnic groups. A positive family history of atopy influenced the CBs IgE concentrations in the white and mixed groups but not in the black group. Of those newborn infants with a CBs IgE concentration greater than 0.5 kU/L, a family history of atopy was found in 100% of the white newborn infants, in 58.3% of the mixed newborn infants, and only in 14.3% of the black newborn infants. Many of the black newborn infants without a family history of atopy had extremely high CBs IgE concentrations. The influence of maternal ascariasis was equivocal in the mixed group but of no significance in the black group. The high CBs IgE concentrations in the black newborn infants, independent of an atopic family history and maternal ascariasis, suggest that this atopic marker may therefore be of limited use in identifying the "high allergic-risk" newborn infant in black Third World populations who appear to represent a pool of genetic high IgE-responder phenotypes.

Ascariasis↗

On the independence of physical and nominal codes: a correlational analysis.

In studies of college students, normal children at three grades, and learning-disabled children, physical and nominal matching procedures were highly correlated, (range .72-.96). In each instance, expected time differences favoring physical matches were replicated. Comparable results were found with both tachistoscopic and paper-and-pencil methods. In two studies where relevant data were available, correlations were not significantly attenuated when the effects of motor speed were partialled out. The results challenge the premise that nominal and physical matching measures are empirically independent, invalidate their application as measures of independent types of information processing, and help explain inconsistent findings in hemispheric specialization research.

Adolescent↗

Oral acanthosis nigricans: report of a case and comparison of oral and cutaneous pathology.

Malignant acanthosis nigricans is usually associated with adenocarcinomas of the digestive tract. The lesions of acanthosis nigricans commonly run a parallel course to the associated malignancy, producing hyperpigmented, roughened plaques on the skin and, sometimes, verruca-like papules on the oral mucosa. The clinical differences between cutaneous and oral acanthosis nigricans are mirrored by the marked differences in the histopathology. Because oral acanthosis nigricans is uncommon, recognizing histologic features may be difficult. The oral lesions have a true acanthosis and epithelial papillary hyperplasia while the cutaneous forms show slight irregular acanthosis that alternates with areas of epidermal atrophy and dermal papillomatosis.

Acanthosis Nigricans↗