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Biomedical subjects

R McKenzie

Publications and source records attributed to R McKenzie.

At least 73 records · Page 4Linked to original sources
PubMed1988

Ultrastructure and morphometric measurements of mesenteric arteries from newborn spontaneously hypertensive rats.

A morphometric and ultrastructural study of superior mesenteric arteries and large mesenteric arteries from newborn spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) was carried out. Morphometric measurements showed that in both vessel types, cross-sectional areas of the lumen and vessel wall components (e.g., media, adventitia) were similar between SHR and WKY. There was also no ultrastructural difference between SHR and WKY in the two types of arteries. We therefore conclude that vascular alterations found in older SHR take place after birth.

Animals↗
PubMed1988

Peptide-containing nerves around blood vessels of stroke-prone spontaneously hypertensive rats.

The distribution and density of nerves containing vasoactive intestinal polypeptide, substance P, and neuropeptide Y around the cerebral and peripheral blood vessels of stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto rats (WKY) were studied using an indirect immunofluorescence technique. Neonatal sympathectomy of SHRSP with anti-nerve growth factor and guanethidine was also carried out to study the effect of sympathectomy on the distribution of these nerves. Vasoactive intestinal polypeptide nerve density was higher in the veins and superior mesenteric artery of SHRSP than of WKY and lower in the cerebral arteries of SHRSP than of WKY, but no difference was found in the muscular mesenteric arteries. Sympathectomy reduced the density of these nerves in all the peripheral vessels but had little effect on the cerebral arteries. Density of substance P nerves was similar between SHRSP and WKY in the peripheral vessels but higher in the cerebral arteries of WKY than of SHRSP. Sympathectomy reduced the density of these nerves in the peripheral vessels but increased the density in some cerebral arteries of SHRSP. Neuropeptide Y nerve density was higher in the peripheral blood vessels of SHRSP than of WKY, and no difference was found in the cerebral arteries. Sympathectomy almost completely removed these nerves in the peripheral vessels but had no effect on the cerebral arteries. We suggest that some of the differences in nerve density between SHRSP and WKY, especially those in the peripheral blood vessels, may be related to the development of hypertension in the SHRSP.

Animals↗
PubMed1987

Low back pain.

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Back Pain↗
PubMed1987

Sequence of the bifunctional ade1 gene in the purine biosynthetic pathway of the fission yeast Schizosaccharomyces pombe.

The ade1 gene of the fission yeast Schizosaccharomyces pombe encodes a bifunctional polypeptide with glycinamide ribotide synthetase (GARSase) and aminoimidazole ribotide synthetase (AIRSase) enzyme activities. These enzyme activities carry out the 2nd and 5th steps, respectively, of the purine synthetic pathway. We report the cloning of the ade1 gene on a 4.4 kb Sau3A insert in the yeast shuttle vector pWH5. Integration of this genomic insert at or near the ade1 locus and its ability to complement, by transformation, three different types of ade1 mutants proved that it contains the ade1 chromosomal gene. Analysis of the nucleotide sequence of this insert revealed the presence of an uninterrupted open reading frame of 2,367 pb. This sequence, and the predicted 789 amino acid sequence encoded, both show a high degree of homology with the functionally equivalent ade5,7 gene sequence of Saccharomyces cerevisiae (approx. 60% overall in both cases) and Gart gene sequences of Drosophila melanogaster. The size of the ade1 RNA transcript is about 2.7 kb.

Amino Acid Sequence↗
PubMed1987

Effect of antimicrobials on blood cultures in endocarditis.

To study the effect of antimicrobials on bacterial growth in blood cultures, we used both simulated blood cultures and cultures obtained from rabbits with experimental endocarditis. Four strains of bacteria were incubated individually with six antimicrobials in nine blood culture media. Positivity rates varied with the ratio of the antimicrobial concentration to the MIC of the organism: 161 of 162 cultures (99%) were positive when the ratio was less than 1/10; 52 of 108 (48%) were positive when the ratio was between 1/10 and one; and none of 54 were positive when the ratio was greater than one. Endocarditis was produced in 28 rabbits with either E. coli, P. aeruginosa, S. aureus, or viridans streptococcus. Following a single dose of an antimicrobial, blood was taken for culture in eight media. Only for viridans streptococcus did recovery rates vary significantly in different media. Recovery rates for this organism in two supplemented peptone broths (78% and 89%) and in hypertonic supplemented peptone (78%) were each higher than in thioglycolate (22%), Columbia (22%), Bactec aerobic and anaerobic (11%), and trypticase soy broths (11%) (p less than 0.05 for each pair). Growth of bacteria in blood cultures containing antimicrobials depended on the ratio of the antimicrobial concentration to the MIC and, for viridans streptococcus, the blood culture medium.

Animals↗
PubMed1986

Topical etidocaine during laparoscopic tubal occlusion for postoperative pain relief.

Narcotic requirements in 51 day-surgery patients following laparoscopic tubal occlusion were significantly reduced (P less than .01) by the use of 1% etidocaine 5 mL, dropped on each fallopian tube from uterus to fimbrias before tubal banding when compared with a control group of 51 day-surgery patients who had no topical anesthetic agent. All patients received general anesthesia. Although there was no significant difference in nausea rate, the incidence of vomiting was decreased. Eight of 51 patients (16%) having topical etidocaine and 19 of 51 (37%) who had no etidocaine vomited during the postoperative period. The frequency of overnight stay was significantly reduced in the topical etidocaine group of patients (P less than or equal to .01).

Acetanilides↗
PubMed1985

Blastomycosis of the esophagus presenting with gastrointestinal bleeding.

A patient with abdominal discomfort and hematemesis was found to have lower esophageal inflammation on endoscopy. A biopsy specimen from this area showed yeast forms of Blastomyces dermatitidis with a polymorphonuclear infiltrate and granuloma formation. Extensive evaluation showed no other bleeding site. Sputum samples obtained earlier also showed B. dermatitidis. Treatment with amphotericin B led to resolution of bleeding and eradication of the fungus on repeat biopsy and sputum samples. An esophageal stricture subsequently developed and required dilation. Seven previously reported cases of esophageal blastomycosis are reviewed.

Aged↗
PubMed1984

Polysaccharide storage in different streptococci.

Calf serum, pooled human plasma, polyvinylpyrollidones (PVP) and polyethylene glycols (PEG) were required as medium components by many cultures of group A.S. pyogenes for intracellular polysaccharide accumulation. These supplements produced a stabilizing effect, probably at the cell surface, and were not associated with nutrition during intracellular iodophilic polysaccharide (IPS) storage. Medium stabilization and the presence of maltose or maltose yielding polysaccharides was found to be a property unique to the group A streptococci. Cariogenic streptococci and Streptococcus agalactive did not require medium stabilization for IPS storage although addition of PVP or PEG was stimulatory. Different degrees of IPS storage in group A.S. pyogenes was found to be strain related and probably dependent on the size and degree of branching of the storage polymer.

Culture Media↗