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Biomedical subjects

D Bryan

Publications and source records attributed to D Bryan.

29 records · Page 2Linked to original sources
PubMed1985

Effect of diabetes on microvascular responses in mouse mesentery.

Mice 8 weeks old were made diabetic with streptozotocin. Their mesenteric arterioles were studied 4-8 weeks later and their responses compared with those of arterioles in control mice. The responses to the dilators acetylcholine and papaverine and to the constrictor prostaglandin F2 alpha were identical in diabetics and controls whether the changes in diameter were expressed as a percent of baseline diameter or in absolute units (microns). Diabetics had significantly smaller responses than controls, to the constrictors norepinephrine and serotonin. However the effect of diabetes on the response to norepinephrine may have been a spurious consequence of expressing constrictions as a percent of slightly differing resting diameters, since the difference became statistically insignificant when constrictions were expressed in absolute units as microns. The reduced response to serotonin remained significant no matter how constriction was expressed. This result, together with a similar finding in an earlier study of diabetes which used much smaller cerebral vessels, suggests that reduced vascular responses to serotonin may be associated with streptozotocin diabetes of relatively recent onset in mice. The reason for this relatively selective impairment of vasomotor response remains obscure, as does the reason for the spared responses to the other vasoactive agents we tested.

Animals↗
PubMed1984

Laminar-airflow equipment certification: what the pharmacist needs to know.

The basic information pharmacy practitioners need to determine the suitability and applicability of laminar-airflow equipment test standards and procedures is presented. The operative guideline for any laminar-flow clean bench (LFCB) certification is the cleanroom and work station requirements for controlled environments as defined by the federal government under Federal Standard 209b (FS 209b). FS 209b outlines the tests, test procedures, and acceptable performance ranges for all LFCB equipment. National Sanitation Foundation Standard Number 49 (NSF 49) is used in the certification of biological-safety cabinets (BSCs). NSF 49 covers those aspects of safety, maintenance, performance, and testing that are unique BSCs. To monitor certification properly, practitioners should be familiar with these standards and the air-velocity profile, high-efficiency particulate air filter performance, noise output, light, and electrical test procedures. A review of the requisite knowledge, experience, and reputation of certifying agents is presented, along with an outline of all the necessary procedures, equipment, and documentation to be used in the process. A thorough test report should be issued upon unit certification. As pharmacy practitioners are responsible for all other aspects of quality assurance, they should also be capable of auditing these certifications to ensure the aseptic quality of products compounded in the laminar-airflow environment.

Equipment and Supplies, Hospital↗
PubMed1981

Contraction of isolated airway smooth muscle by synthetic leukotrienes C4 and D4.

The pharmacology of leukotrienes (LT) C4 and D4 in isolated airway smooth muscle was investigated. In rat trachea, neither LTC4 or D4 elicited a response. In contrast, LTC4 was a potent contractile agonist in guinea-pig trachea, bronchus and parenchymal lung strip. Similar effects were obtained with LTD4 in trachea and parenchyma. In trachea and bronchus, the concentration-response curve to LTC4 was biphasic: indomethacin converted the biphasic response curve to a simple sigmoidal shape and enhanced the maximum contractile response. The SRS-A antagonist FPL 55712 antagonized the effect of LTD4 in both trachea and parenchyma. As regards LTC4-induced contraction of trachea and bronchus, FPL 55712, depending on concentration, either antagonized, or antagonized and enhanced the maximum contractile response. The enhancement of the maximum contractile response by FPL 55712 was not apparent when indomethacin was present. FPL 55712 failed to antagonize the effect of LTC4 in parenchyma.

Animals↗
PubMed1981

Case report. Diagnosis of ovarian vein thrombophlebitis by computed tomography.

The diagnosis of postpartum ovarian vein thrombophlebitis has in the past been based purely on either clinical findings or surgical findings. There is almost no mention of this entity in the diagnostic imaging literature, a reflection of the lack of a means to demonstrate the vein that has existed to this time. We present a case in which the thrombosed vein and the surrounding inflammatory mass were demonstrated preoperatively by computed tomography (CT). We believe that CT may greatly facilitate the diagnosis of this potentially serious disorder.

Adult↗
PubMed1981

Tetraploidy in a liveborn infant with spina bifida and other anomalies.

Although tetraploidy of human chromosomes (92,XXYY) has been described frequently in abortuses, only one example in a liveborn infant has previously been described. A second malformed infant with a complete tetraploid chromosome complement, who lived for 15 days, is reported. In addition to many of the malformations described in the first case, this infant also had a sacral myelomeningocele and skeletal anomalies. The probable origin of the tetraploidy was a failure of cytoplasmic cleavage at the first mitotic division of the fertilised ovum.

Abnormalities, Multiple↗
PubMedDate not supplied

Septo-hippocampal cholinergic and neurotrophin markers in age-induced cognitive decline.

Messenger RNA (mRNA) molecules encoding proteins related to the presynaptic cholinergic and neurotrophin systems were quantitated in the hippocampus and basal forebrain of Long-Evans rats with spatial learning ability assessed in the Morris water maze. The reverse transcriptase-polymerase chain reaction showed that the mRNAs for the low-affinity neurotrophin receptor (p75-NTR) and the growth-associated protein GAP-43 were decreased in level in the basal forebrain of aged-impaired rats. In the hippocampus of these aged-impaired rats, the mRNA for VGF, another neurotrophin-inducible gene, also was decreased. In situ hybridization histochemistry revealed that mRNAs for nerve growth factor (NGF) and brain-derived neurotrophic factor increased in level in the aged rat hippocampus; when age effects were removed, NGF mRNA level remained significantly correlated with maze performance. Enzyme-linked immunosorbent assay indicated that NGF protein was expressed at normal levels in the aged rat hippocampus. These mRNA and protein alterations may signify that a defect in neurotrophin signaling exists in the brains of aged Long-Evans rats, underlying reduced plasticity responses in the basal forebrain cholinergic system.

Aging↗
PubMedDate not supplied

Evidence that in vivo constriction of cerebral arterioles by local application of tert-butyl hydroperoxide is mediated by release of endogenous thromboxane.

Pial arterioles of mice were suffused in situ with tert-butyl hydroperoxide (TBHP). This agent has been reported to stimulate synthesis or release of the constrictor, thromboxane. In the present study we observed pial arterioles by in vivo microscopy. Locally applied TBHP produced dose-dependent constriction, significantly inhibited by each of three drugs: acetylsalicylic acid, OKY-046, and SQ-29548. These drugs are respectively a cyclooxygenase inhibitor, a thromboxane synthetase inhibitor, and a thromboxane receptor blocker. Since each acts by a different mechanism to interfere with thromboxane-mediated responses and each inhibited the contractile response to TBHP, thromboxane appears to be a mediator of this response. Platelet aggregation was not seen after local application of TBHP, and the dwell time of platelets at the site of TBHP application is less than 1 second. Thus, platelets are an unlikely source of the thromboxane mediating the local constriction. It is much more likely that the source of thromboxane is either the wall of the pial vessels or the underlying brain and/or its vessels. These data do not distinguish between the latter two possibilities, but if this suggestion is correct, then the data show for the first time that thromboxane can be released from normal brain and/or brain vessels in amounts sufficient to cause arteriolar constriction.

Animals↗