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Biomedical subjects

P Robinson

Publications and source records attributed to P Robinson.

At least 199 records · Page 11Linked to original sources
PubMed1992

Periodontal diseases and HIV infection. A review of the literature.

There have been many references in the literature to HIV-related periodontal diseases, which although poorly substantiated, seem to have established them as part of the expected range of HIV-associated conditions. The original studies have produced conflicting reports which may stem from shortcomings in design. Consequently, the picture remains confused with respect to the classification, epidemiology, microbiology, natural history and management of HIV-related periodontal diseases. Future studies should give greater attention to sampling methods, the use of control groups and defining criteria. This will allow comparison of data between centres and facilitate study of what may be an uncommon disease.

HIV Infections↗
PubMed1992

In vivo loads on airway smooth muscle: the role of noncontractile airway structures.

The degree of airway smooth muscle contraction and shortening that occurs in vivo is modified by many factors, including those that influence the degree of muscle activation, the resting muscle length, and the loads against which the muscle contracts. Canine trachealis muscle will shorten up to 70% of starting length from optimal length in vitro but will only shorten by around 30% in vivo. This limitation of shortening may be a result of the muscle shortening against an elastic load such as could be applied by tracheal cartilage. Limitation of airway smooth muscle shortening in smaller airways may be the result of contraction against an elastic load, such as could be applied by lung parenchymal recoil. Measurement of the elastic loads applied by the tracheal cartilage to the trachealis muscle and by lung parenchymal recoil to smooth muscle of smaller airways were performed in canine preparations. In both experiments the calculated elastic loads applied by the cartilage and the parenchymal recoil explained in part the limitation of maximal active shortening and airway narrowing observed. We conclude that the elastic loads provided by surrounding structures are important in determining the degree of airway smooth muscle shortening and the resultant airway narrowing.

Animals↗
PubMed1991

'HIV update'.

Explore the source record for details and available documents.

HIV Infections↗
PubMed1991

A placebo-controlled trial of maintenance therapy with fluconazole after treatment of cryptococcal meningitis in the acquired immunodeficiency syndrome. California Collaborative Treatment Group.

BACKGROUND AND METHODS: In patients with the acquired immunodeficiency syndrome (AIDS), the rate of relapse after primary treatment for cryptococcal meningitis remains high. We conducted a controlled, double-blind trial to evaluate the efficacy of maintenance therapy with fluconazole. At entry into the study, all participants had sterile cultures of cerebrospinal fluid, blood, and urine after following a standardized course of therapy for culture-proved cryptococcal meningitis. The patients were randomly assigned to take either fluconazole or placebo as maintenance therapy. The dose of fluconazole was 100 mg daily in the first phase of study and 200 mg daily in the second phase. RESULTS: Of 84 patients initially enrolled, 16 (19 percent) were found to have silent, persistent infection on the basis of cultures that became positive after entry into the study; 7 other patients were lost to follow-up shortly after entry. Of the remaining 61 patients, 10 of 27 assigned to placebo (37 percent) and 1 of 34 assigned to fluconazole (3 percent) had a recurrence of cryptococcal infection at any site (difference in risk, 34 percent; 95 percent confidence interval, 15 to 53). Of the 11 recurrent infections, 7 were detected in urine obtained after prostatic massage. There were four recurrent meningeal infections in the patients taking placebo, but none in those taking fluconazole (mean duration of follow-up, 164 days) (P = 0.03). In multivariate analyses, the best predictors of recurrence-free survival were fluconazole treatment (P = 0.02; relative hazard, 13.2), a lower serum cryptococcal-antigen titer (P = 0.05; relative hazard, 1.2), and more prolonged primary therapy with flucytosine (P = 0.09; relative hazard, 1.1). Survival and toxicity were similar in the two maintenance-treatment groups. CONCLUSIONS: In patients with AIDS, silent persistent infection is common after clinically successful treatment for cryptococcal meningitis. Maintenance therapy with fluconazole is highly effective in preventing recurrent cryptococcal infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Rapid diagnosis of medium-chain acyl CoA dehydrogenase deficiency by measurement of cis-4-decenoic acid in plasma.

Plasma concentrations of octanoate and cis-4-decenoate were measured by gas chromatography-mass spectrometry in children with deficiencies of medium-chain acyl-CoA dehydrogenase (MCAD), long-chain 3-hydroxyacyl-CoA dehydrogenase (3LHAD) and multiple acyl-CoA dehydrogenase (MAD) deficiency. Children receiving medium- and long-chain lipid supplements were also studied. Octanoate was elevated in all but one of the children with MCAD deficiency, in MAD deficiency and in children receiving medium-chain triglyceride supplementation. Cis-4-decenoate was only elevated in MCAD and MAD deficiency. It is concluded that measurement of plasma cis-4-decenoate provides a sensitive and specific test for defects of medium-chain acyl CoA dehydrogenase.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1991

Reduced thrombogenicity of artificial materials by coating with ADPase.

A novel coating solution for the improvement of biocompatibility of polyurethane-based vascular prostheses was tested in rabbits and rats in vivo. Segments of coated and uncoated vascular prostheses were implanted into the peritoneal cavity of rats, followed by induction of experimental haemorrhage; otherwise whole vascular prostheses were implanted in the carotid artery of rabbits using microsurgical procedures. While in both rats and rabbits, the uncoated material showed abundant formation of fibrinoid thrombi, clear reduction of thrombus formation was seen in all ADPase coated materials following implantation in vivo.

Animals↗
PubMed1991

Expression and function of Qa-2 major histocompatibility complex class I molecules in transgenic mice.

Qa-2 molecules are weak transplantation antigens encoded by class I genes of the major histocompatibility complex. When expressed in transgenic CBA mice, Qa-2 molecules provoke rapid rejection of skin grafts and strong, Qa-2 specific, cytotoxic T-cell responses. Efficient rejection of skin grafts from Qa-2 transgenic mice takes place when Qa-2 molecules are attached to the cell membrane with a glycophosphatidyl anchor or by a transmembrane protein domain, except that rejection times are slightly longer in the former case. These results demonstrate that Qa-2 molecules can behave as major transplantation antigens, as do closely related H-2 molecules. Failure of Qa-2 molecules to provoke strong T-cell responses in non-transgenic mice is probably due to the very low level of expression of Qa-2 molecules in skin keratinocytes from such mice since these cells express increased levels of Qa-2 molecules in all Qa-2 transgenic mice.

Animals↗
PubMed1991

Specific immune response in the human respiratory tract following oral immunization with live typhoid vaccine.

Specific antibody responses in the lower respiratory tract of human subjects to orally administered Salmonella typhi Ty21a are reported. These responses, predominantly of the immunoglobulin G class, were determined to be a transudate from serum. These results were supported by the similarity in responses to parenteral administration of heat-killed typhoid vaccine. Specific immunoglobulin A antibody was a poor contributor to the respiratory antibody response to either vaccine.

Administration, Oral↗
PubMed1991

A model for evaluating the delivery of pediatric primary care services.

This evaluation model describes the components used to assess the functioning of Pediatric Resource Centers which provide primary care to high risk children in New York City. These centers are administered by the Medical and Health Research Association of New York City and are funded by the State through the New York City Department of Health. Measurements are made of: accessibility, availability, accountability, productivity and patient volumes, continuity, coordination, and comprehensiveness. Data is collected from the PRC data reporting system, site visits, chart reviews, and fiscal reports. The findings vary considerably among the different centers with compliance to the various assessments, differing not only within a given center but between centers. In spite of some methodological limitations, it is felt that these measurements are effective in pointing out problem areas in the centers and are helpful to the funding agency in focusing on program areas in need of greater support.

Child↗
PubMed1991

Isolation and characterization of three forms of joining peptide from adult human pituitaries: lack of adrenal androgen-stimulating activity.

Three structural variants of the joining peptide (JP) fragment of POMC have been purified from human pituitaries. Ion exchange and reverse phase tissue extraction procedures were combined with reverse phase HPLC to achieve complete purification of each form of JP. Fragments resulting from tryptic hydrolysis of each form were characterized by amino acid analysis and fast atom bombardment mass spectrometry. The predominant form of human JP, accounting for about 50% of the total purified, was found to be conjugated to glutathione through the lone cysteine residue at position 9. The other two variants were identified as human JP with a free cysteine residue and human JP dimer and accounted for 35% and 15%, respectively, of the total purified. Recently, human JP-(1-18) has been suggested as having adrenal androgen-stimulating activity. None of the three JP variants or their respective 1-20 amino-terminal fragments resulting from tryptic hydrolysis showed any ability to promote the secretion of dehydroepiandrosterone sulfate by cultured human fetal adrenal cells. Similarly, no potentiation of the stimulatory effects of ACTH-(1-39) was observed. The three variants of human JP as well as JP purified from rat, porcine, and bovine pituitaries were tested for their ability to stimulate androgenic steroids from dispersed fetal rabbit adrenal cells. None showed any significant biological activity either in stimulating steroid secretion or in potentiating the action of ACTH-(1-39).

Adrenal Glands↗