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Biomedical subjects

M M Taylor

Publications and source records attributed to M M Taylor.

At least 19 recordsLinked to original sources
PubMed1995

Intraocular bacterial contamination during cataract surgery in dogs.

Prevalence of intraoperative contamination of the eyelids, conjunctival sac, and aqueous humor of 50 canine eyes that underwent elective cataract surgery was determined, and the short-term outcomes for contaminated and noncontaminated eyes were compared by scoring media clarity, pupil size and shape, and behavioral evidence of vision during the initial 30-day postoperative period. Results of bacteriologic culture of anterior chamber samples were positive for 12 of the 50 (24%) eyes, but anterior chamber contamination was unrelated to results of bacteriologic culture of eyelids or conjunctival sac swab samples. Eyes undergoing phacoemulsification were less likely to be contaminated than were eyes undergoing intra- or extracapsular extraction. Eyes undergoing intra- or extracapsular extraction and eyes with anterior chamber contamination had a greater likelihood of developing glaucoma postoperatively. We did not detect an association between intraocular contamination and the surgeon performing the operation, the need for postoperative administration of tissue plasminogen activator, or the presence or absence of diabetes mellitus. Also, we did not detect any differences in outcome between eyes with and without intraocular contamination. Despite intraoperative bacterial contamination of the anterior chamber, bacterial endophthalmitis did not develop in any of the eyes.

Animals↗
PubMed1990

Simple assay of calcium dependency for virulent plasmid-bearing clones of Yersinia enterocolitica.

A simplified procedure to detect the calcium dependency of virulent plasmid-bearing strains of Yersinia enterocolitica was developed. A low-calcium, agarose-based medium of brain heat infusion with added magnesium effectively differentiated plasmid-bearing and plasmidless isolates. Further, the expression of calcium dependency in plasmid-bearing strains of Y. enterocolitica as measured by the average colony diameter was proportional to the calcium concentration of the assay.

Calcium↗
PubMed1989

Unsuspected damage to lumbar zygapophyseal (facet) joints after motor-vehicle accidents.

Three zygapophyseal joints from each of 31 lumbar spines of subjects who died of injuries (mostly as a result of motor-vehicle accidents) were sectioned for low-power histological study. Bony injuries, in the form of fractures of the superior articular process or infractions of the subchondral bone plate, were found in 11 of the 31 subjects and soft-tissue injuries to the capsule or articular cartilage were found in one-or-more joints in 24 of the 31 subjects, with capsular and articular-cartilage damage in 77% of cases. Healed injuries of a similar type, which were unrelated to the cause of death, were found in other lumbar spines. None of these lesions was diagnosed by standard radiological examination of the spine post mortem. It is suggested that, in survivors, bony and soft-tissue injuries to zygapophyseal joints may result in considerable pain and dysfunction and may predispose to early arthritis.

Accidents, Traffic↗
PubMed1984

Gastric stapling for morbid obesity: gastrointestinal response in a rat model.

The adaptive response of the gastrointestinal tract to gastric stapling was studied in a Zucker (fafa) genetically obese rat model. The effects of gastric stapling in rats with a Roux-en-Y gastrojejunostomy were compared to Roux-en-Y and intact controls. Rats (225 to 275 g) were divided into three groups: group I (GI), Roux-en-Y, stapled, ad libitum fed; group II, Roux-en-Y, unstapled; and group III, intact (laparotomy only). Groups II and III were further subdivided into group IIA (GIIA) and group IIIA (GIIIA), pair-fed to GI; and group IIB (GIIB) and Group IIIB (GIIIB), fed ad libitum. All rats were fed a diet of liquid rat formula and rat food (50:50 cal ratio). After 2 wk rats were killed and the liver, pancreas, and stomach removed, weighed, and tissue taken for histology. The intestine was divided into three segments corresponding to the excluded segment (1, duodenum), transposed segment (2, jejunum), and ileal segment (3), with tissue taken for histology. Liver lipid, pancreatic amylase, serum amylase and gastrin, and intestinal mucosal protein and DNA were measured. Weight gain, g/14 days, was: GI, 24.1 +/- 7.8; GIIA, 17.0 +/- 2.0; GIIB, 42.6 +/- 4.8; GIIIA, 17.6 +/- 4.7; GIIIB, 54.6 +/- 8.9. All rats were in positive N balance. Liver weight and lipid were similar in all groups. Pancreatic mass was significantly increased in all Roux-en-Y animals, while amylase activity per g tissue was significantly less than in intact animals. Stapled rats had atrophy of the glandular portion of the stomach, decreased stomach mucosal weight, and lower serum gastrin concentration compared with all other rats (p less than 0.01). In stapled rats, segment weight and mucosal weight were lower in the excluded segment, and higher in the transposed segment, compared to all other rats. Tissue pathology was found only in stapled rats: gastric atrophy, focal fibrosis of gastric wall, peritonitis, minimal to mild multifocal hepatitis, and mild periductal fibrosis of the pancreas. There are significant early adaptive and pathological changes after gastric stapling in the rat.

Adaptation, Physiological↗
PubMed1983

PEST reduces bias in forced choice psychophysics.

Observers performed several different detection tasks using both the PEST adaptive psychophysical procedure and a fixed-level (method of constant stimuli) psychophysical procedure. In two experiments, PEST runs targeted at P (C) = 0.80 were immediately followed by fixed-level detection runs presented at the difficulty level resulting from the PEST run. The fixed-level runs yielded P (C) about 0.75. During the fixed-level runs, the probability of a correct response was greater when the preceding response was correct than when it was wrong. Observers, even highly trained ones, perform in a nonstationary manner. The sequential dependency data can be used to determine a lower bound for the observer's "true" capability when performing optimally; this lower bound is close to the PEST target, and well above the forced choice P (C). The observer's "true" capability is the measure used by most theories of detection performance. A further experiment compared psychometric functions obtained from a set of PEST runs using different targets with those obtained from blocks of fixed-level trials at different levels. PEST results were more stable across observers, performance at all but the highest signal levels was better with PEST, and the PEST psychometric functions had shallower slopes. We hypothesize that PEST permits the observer to keep track of what he is trying to detect, whereas in the fixed-level method performance is disrupted by memory failure. Some recently suggested "more virulent" versions of PEST may be subject to biases similar to those of the fixed-level procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Auditory Perception↗
PubMed1983

Retrolental fibroplasia: further clinical evidence and ultrastructural support for efficacy of vitamin E in the preterm infant.

To further evaluate the efficacy of oral vitamin E in preventing the development of severe retrolental fibroplasia (RLF) in very low-birth-weight infants, 100 infants treated with 100 mg/kg/d of vitamin E (dl-alpha-tocopheryl acetate) were compared with 75 infants treated with 5 mg/kg/d of vitamin E (dl-alpha-tocopherol) in the same nursery during the previous year. All 175 infants weighed less than or equal to 1,500 g at birth and required supplemental oxygen. A total of 120 infants (69 treatment; 51 control) survived greater than or equal to 10 weeks. Multivariate analysis of the control population identified five risk factors (P less than or equal to .10): gestational age, level and duration of oxygen administration, intraventricular hemorrhage, sepsis, and birth weight. When multivariate analysis was applied to both control and treatment groups, the severity of RLF was found to be significantly reduced in infants given the treatment dose of vitamin E (P = .003). Ultrastructural analyses of 58 pairs of whole-eye donations from high-risk infants surviving less than 10 weeks suggest that the initial morphologic event is gap junction increases between the plasma membranes of adjacent spindle cells of the van-guard retina. Such extensively gap junction-linked spindle cells are apparently removed from the vasoformative process as early as 4 days of life, forming a barrier to further normal vascular development and triggering retinal and vitreal neovascularizations approximately 8 weeks later. These events are maximally suppressed by elevated plasma vitamin E levels in infants greater than or equal to 27 weeks gestational age.

Cell Membrane↗
PubMed1981

Microscopic examination of the intracellular fate of infectious herpes simplex virus DNA.

The intracellular fate of 3H-labeled exogenous herpes simplex virus type 2 DNA following the exposure of recipient cells to selected DNA facilitators and the ultrastructural changes which ensued in transfected cultures were examined. In most cases, electron microscopic radioautography demonstrated that exogenous DNA reached the nucleus within 1 h postinoculation. At later time periods, enlargement of nuclei and margination of chromatin were noted. Cells treated with polyornithine differed significantly from those treated with other facilitators in that large cytoplasmic accumulations of labeled material associated with electron-dense, membrane-bound bodies persisted after 1 h postinoculation. In contrast, labeled DNA released by intact virions was detected in the nucleus as early as 20 min postinfection (p.i.), and progeny virus was evident by 8 h p.i. These results suggest that the efficiency of each facilitator is related to the rapidity with which exogenous DNA penetrates the recipient cell, traverses the cytoplasm, and the amount of DNA which is finally associated with the nuclear compartment.

Alkaloids↗
PubMed1977

35S-Sulfide incorporation during alkaline treatment of keratin and its relation to lanthionine formation.

Cattle hair exposed to solutions of 35S-sulfide ions at pH 12.5, hydrolyzed with acid, and analyzed for amino acids with simultaneous measurement of the radioactivity of the eluate from the analytical column showed 87 percent of the radioactivity incorporated in the hair in three amino acids: cysteic acid, lanthionine, and cystine. This and other evidence presented lend further support to the intermediacy of dehydroalanyl residues formed by a beta-elimination reaction in the conversion of cystinyl residues to lanthionyl residues in proteins. The presence of radioactively labelled cystine in the hydrolyzate indicates that the dehydroalanyl residues are also capable of reforming cystinyl residues under these same conditions through a series of reversible reactions.

Alanine↗
PubMed1976

Antigen-induced lymphocyte blastogenesis in a hookworm (Necator americanus) infection in man.

A lymphocyte blastogenic technique was employed to examine cell-mediated immunity in a Necator americanus infection. Infective third-stage larvae of N. americanus were jsed for antigen preparation, and lymphocyte cultures were prepared from peripheral blood taken on days 3, 17, and 51 after infection with 250 third-stage larvae of N. americanus. At 3 days post-infection lymphocyte transformation was not induced; at 17 and 51 days after infection significant transformation was obtained.

Hookworm Infections↗
PubMed1975

The water agar test: a new test to measure the bacteriological quality of cream.

A new test, the water agar test, is described that gives a qualitative index of the presence of bacteria that indicate contamination of the cream, poor storage conditions or both of these factors. The method is simple and requires little equipment. The bacteria grow in a film of diluted cream adsorbed on the surface of a non-nutrient base. After incubation at 30 +/- 0-5 degrees C. for 18-20 hr., a proteolytic and mucoid colony count is obtained which has the same percentage coefficient of variance as a standard plate count. An examination of the effect of storage at different temperatures on the types of bacteria present in cream showed that of all the tests done initially, only the water agar test could predict subsequent bacterial growth with any consistency. The multiplication of presumptive coliform organisms occurred even at 3-5 degrees C. Irrespective of the colony count, the methylene blue reduction time was not shorter than 7 1/2 hr. unless the bacteria were in the logarithmic phase of growth when sampled. A survey was made of the bacterial flora of 188 retail samples of double cream of 15 different brands. The age of the samples varied from freshly separated cream to cream that had been kept in the shop for a day longer than that recommended for sale. The water agar test was compared with the colony count, the presumptive coliform test, a confirmatory coliform count in violet red-bile agar, a lipolytic colony count, a staphylococcal count and the methylene blue reduction test.

Agar↗