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Biomedical subjects

R Thomson

Publications and source records attributed to R Thomson.

At least 109 records · Page 6Linked to original sources
PubMed1989

Protection of crystal-induced polymorphonuclear leukocyte membranolysis by phosphocitrate.

The protection afforded by phosphocitrate, a phosphorylated polycarboxylic acid, against crystal-induced membrane damage to polymorphonuclear leukocytes was studied in vitro. Membranolysis was assessed by nitro blue tetrazolium salt reduction, lactate dehydrogenase release, and scanning electron microscopy. Phosphocitrate protected strongly against hydroxyapatite crystal-induced damage, an action attributable to crystal surface binding of phosphocitrate rather than to the membrane. The ability of phosphocitrate to prevent hydroxyapatite crystallization, together with its membrane protective effect against preformed crystals, would suggest that the compound might have a useful future role against crystal-induced arthropathies.

Apatites↗
PubMed1989

Congenital cystic adenomatoid malformation of the lung. Presentation of 16 cases.

Congenital cystic adenomatoid malformation (CCAM) of the lung is one of the rarest causes of neonatal distress. The principal radiological sign of CCAM is an intrapulmonary mass of soft tissue density, containing cystic areas of different sizes and shapes. The mass usually compresses the rest of the affected lung and displaces the mediastinum and heart to the opposite side, compressing the lung which is often therefore hypoplastic. If CCAM is diagnosed in utero by ultrasound, the treatment of choice is surgery as soon as possible after birth, with good survival rates. Sixteen cases of CCAM are presented, one with bilateral disease, diagnosed at different times, and one with an associated prune belly syndrome, to be added to the 405 already reported in the literature, and their clinical, radiological and pathological features are described.

Diagnosis, Differential↗
PubMed1989

Receptor number determines latency and amplitude of the thyrotropin-releasing hormone response in Xenopus oocytes injected with pituitary RNA.

TRH evokes depolarizing membrane electrical responses in Xenopus laevis oocytes injected with RNA from pituitary cells. We have shown previously that the amplitude of this response is directly proportional to the dose of TRH and the amount of RNA injected. Herein we show that the number of TRH receptors expressed on oocytes after injection of rat pituitary (GH3) cell RNA or mouse thyrotropic (TtT) tumor RNA determines the latency as well as the amplitude of the response. In oocytes injected with a maximally effective amount of GH3 cell RNA, the latency of the response decreased from a maximal duration of 103 +/- 16 to 10 +/- 1 sec when the TRH concentration was increased from 5 to 3000 nM. When oocytes injected with different amounts of GH3 cell RNA were stimulated with 3000 nM TRH, the latency decreased from 31 +/- 4 to 11 +/- 0.5 sec when the amount of RNA injected was increased from 30 to 400 ng. Specific binding of [3H]methylhistidine-TRH increased when increasing amounts of TtT poly(A)+ RNA was injected, and binding correlated with increased response amplitude. To show that these effects were caused by mRNA for the TRH receptor and did not depend on other mRNAs, TtT poly(A)+ RNA was fractionated on a sucrose gradient. Using RNA from each fraction, there was an inverse correlation between response amplitude and latency. For size-fractionated RNA, as for unfractionated RNA, there was a direct correlation between specific [3H]methylhistidine-TRH binding and response amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Cross-infection between animals and man: possible feline transmission of Staphylococcus aureus infection in humans?

An outbreak of epidemic methicillin-resistant Staphylococcus aureus occurred on a rehabilitation geriatric ward. Intensive screening of patients and staff revealed an unusually high carriage rate in the nursing staff (38%), thought to be related to a ward cat which was heavily colonized from the environment. Infection control measures and removal of the cat led to rapid resolution of the outbreak.

Aged↗
PubMed1988

Reduction of infection stones in rats by combined antibiotic and phosphocitrate therapy.

The potential of phosphocitrate to inhibit infection stones in rats when combined with an antibiotic was studied. A significant reduction occurred in both the number and weight of recovered stones from rats receiving combined treatment with amoxycillin (50 mg./kg. body wt./day and phosphocitrate (112 mumol./kg. body wt./day) for four weeks. The inhibitory responses were attributed to the intact phosphocitrate molecule as administration of citrate in equimolar concentrations did not mimic the observed effects of phosphocitrate. In comparison with non-infected controls, antibiotic treatment alone failed to eliminate total stone growth. However, composition of the stone reverted from predominantly struvite to a mixture of struvite and newberyite as urinary parameters normalized. The studies highlight the usefulness of phosphocitrate to restrict magnesium salt deposition in vivo.

Amoxicillin↗
PubMed1988

Prospective comparison of traditional and pharmacokinetic aminoglycoside dosing methods.

Aminoglycoside (gentamicin, tobramycin) dosage regimens and subsequent serum concentrations were compared in 30 patients treated initially using traditional physician-determined methods and then switched to a pharmacokinetic-based treatment program. Patients received more drug during the kinetic phase (median 5 mg/kg) than during the traditional phase (median 3.6 mg/kg) and achieved greater peak serum concentration (5.9 vs. 4.4 micrograms/ml). Seventy-three percent of kinetic peak values but only 27% of traditional peak values exceeded 5.0 micrograms/ml. Trough concentrations were comparable in both phases of study and no nephrotoxicity was observed. This pharmacokinetic-based management program achieved more consistently greater therapeutic peak concentrations and provided more individualized therapy than did physicians. The use of pharmacokinetic consultants may be of benefit in administering safely optimal aminoglycoside therapy.

Gentamicins↗
PubMed1987

Confirmation of a suspected 16q deletion in a dysmorphic child by flow karyotype analysis.

Cytogenetic examination of a dysmorphic infant with multiple congenital abnormalities revealed a possible de novo interstitial deletion in the long arm of chromosome 16. Conclusive proof of the deletion was obtained by flow karyotype analysis of the patient and both parents, which showed that the deleted segment was approximately 7000 kb in size.

Abnormalities, Multiple↗
PubMed1985

A quality control analysis of aminoglycoside management.

Aminoglycoside administration practices were evaluated in a teaching hospital using three study methods: a chart review of 40 randomly selected patients receiving aminoglycosides was conducted retrospectively; 93 health care personnel involved in ordering and administering aminoglycosides to patients were interviewed regarding their understanding of aminoglycoside utilization practices; and ten patients having serum peak and trough aminoglycoside determinations were closely monitored for accuracy of dose administration and obtaining blood specimens at appropriate times. The chart review showed that during 15 of 32 evaluable therapy courses no determinations of serum aminoglycoside concentration were obtained. The survey demonstrated that only 24% of the residents actually used the results of peak and trough determinations to adjust dosage regimens. Direct observation of health care personnel disclosed only two of ten instances in which doses were administered and serum concentration specimens obtained with no apparent problems. Most personnel in our hospital were unaware of these pervasive suboptimal or inconsistent practices associated with aminoglycoside administration and interpretation of laboratory results.

Aminoglycosides↗
PubMed1982

Side effects and placebo amplification.

A sample of placebo-controlled tricyclic antidepressant studies was examined retrospectively to determine whether there was any difference in the relative efficacy of the tricyclic when it was compared against an inert placebo as against an active (atropine) placebo with anticholinergic side effects. Fewer studies showed a significant difference between atropine placebo and drug than between inert placebo and drug. The possibilities that atropine has a specific antidepressant effect, or that side effects amplify placebo responses are considered.

Antidepressive Agents, Tricyclic↗
PubMed1981

Immunological studies of the human placenta: functional and morphological analysis of pregnancy-associated plasma protein A (PAPP-A).

A blood protein, pregnancy-associated plasma protein A (PAPP-A), has been isolated from the plasma of pregnant women. An antiserum to this protein has been prepared and used to localize the protein within the placenta by immunofluorescence. It was found to be inconstantly present in the syncytiotrophoblast and intervillous fibrin. Neither antiserum nor antigen exerts a cytotoxic effect on peripheral blood lymphocytes, and neither affected blastogenic responses of lymphocytes to mitogens or in mixed lymphocyte culture reactions.

Cytotoxicity, Immunologic↗
PubMed1980

The use of "fresh" unstented homograft valves for replacement of the aortic valve. Analysis of 8 years' experience.

Between August, 1969 and May 1978, 679 patients underwent homograft replacement of the aortic valve. Isolated elective valve replacement was performed in 411 patients. Thirty-four patients had total aortic root replacement with reimplantation of the coronary arteries. There were 16 early deaths (3.9%) and 43 late deaths (10.5%) during a follow-up between 3 and 102 months (mean 47 months). Actuarial analysis showed 87% survival at 5 years and 81% at 8 years. Valve failure occurred in 24 patients (5.9%) owing to prolapse of one cusp in eight patients (2.0%), infective endocarditis in seven patients (1.7%), and degeneration of the valve in nine patients (2.2%). Degenerative valve failure was encountered after the fourth year with an incidence of 4.8% of patients at risk and occurred only in grafts from donors over the age of 65 years. Diastolic murmurs were present in 28% of patients followed beyond 1 month and increased very slightly with time. Systemic embolism was not recorded in any patient despite the fact that anticoagulants were not used. The clinical results were judged to be good or excellent in 89% of patients. It is concluded that homograft replacement of the aortic valve gives satisfactory results with a low incidence of late valve failure.

Adolescent↗