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Biomedical subjects

D L Stewart

Publications and source records attributed to D L Stewart.

15 recordsLinked to original sources

Extracorporeal membrane oxygenation and early-onset group B streptococcal sepsis.

Recently, extracorporeal membrane oxygenation (ECMO) has been used as rescue therapy for newborns with overwhelming early-onset group B streptococcal sepsis. To determine which clinical factors best predict mortality and to evaluate the outcome of this therapy, a retrospective examination of the clinical course and outcome of ECMO-eligible newborns with early-onset group B streptococcal sepsis was undertaken. The study period was divided into two phases based on when ECMO was initially used at Kosair Children's Hospital as therapy for septic neonates. Phase 1 (pre-ECMO) was the period from January 1, 1982, through June 15, 1986, and phase 2 (ECMO) from June 16, 1986, through December 31, 1989. Newborns with gestational age greater than or equal to 34 weeks, birth weight greater than or equal to 2000 g, and evidence of early-onset group B streptococcal sepsis were eligible for study. Only newborns who received mechanical ventilation were evaluated. Sixteen patients from phase 1 met the above criteria. Of those, 10 exhibited no sign of hypotension and all survived. Of the 6 patients with hypotension, 3 died. Forty patients were identified from phase 2. Seven patients remained normotensive and all survived. Thirty-three patients were hypotensive, of which 15 received ECMO and 13 survived. Of the 18 who did not receive ECMO, 7 died. Regarding all hypotensive newborns, those who did not receive ECMO had a trend toward lower survival (P less than .06) and were more likely to die if they were of lower birth weight, manifested a persistent acidosis (pH less than or equal to 7.25), and had an absolute neutrophil count less than 500 cells/mm3.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis

Attitudes toward condom use and AIDS among patients from an urban family practice center.

As part of an effort to better educate patients about using condoms, a survey was done to assess the sexual practices, attitudes toward acquired immunodeficiency syndrome (AIDS) and condom use by patients who visit an urban family practice center. A self-administered questionnaire was given to 126 patients of whom the majority were black and single. Seventeen percent indicated they had sex with more than one person in the 3 months before the survey. Within the last 5 years, 10% had sex with an intravenous drug abuser, and 6% with someone of the same sex. Fifty percent believed that condoms decrease sexual pleasure for men and 31% thought condoms made sex inconvenient. Twenty-seven percent of those surveyed believed that a man's penis may be too large for a condom and 18% believed that uncircumcised men could not use condoms. Forty-five percent believed they should be screened for human immune deficiency virus exposure. The results highlight attitudes and beliefs that may function as barriers to condom use and should be addressed when encouraging condom use with this population.

Acquired Immunodeficiency Syndrome

The effects of cooling to 5 degrees C and freezing and thawing on the ultrastructure of bull spermatozoa.

Semen from 6 bulls was examined under the transmission electron microscope immediately after collection, after dilution and cooling to 5 degrees C and after freezing and thawing. Conception rates were determined following artificial insemination of the frozen and thawed semen. Dilution and cooling to 5 degrees C caused acrosomal swelling in about 50% of the spermatozoa. Subsequent freezing and thawing caused considerable ultrastructural changes to the acrosomes (disruption of the plasma and outer acrosomal membranes and dispersion of the acrosomal contents) and middle pieces (breakage of the plasma membrane and a reduction in the electron density of the mitochondrial matrix) of a high proportion of spermatozoa. The average non-return rate following insemination of semen from 5 of the bulls was 61.6% and higher (P greater than 0.001) than for the sixth bull (15%). Although this difference in semen viability was also demonstrated in the structural studies (acrosome, P greater than 0.05: middle piece, P greater than 0.001), more work is required to assess the relationship between structure and function of spermatozoa.

Animals

Pancreatic retention cyst secondary to chronic pancreatitis. A cause of hemobilia.

We describe a 47-year-old male with chronic calcific pancreatitis who had a four-year history of occult gastrointestinal bleeding with three prior hospitalizations. At endoscopy on the fourth admission, hemobilia was identified. Arteriography showed a 3-cm-diameter dye blush in the head of the pancreas. A retention cyst had eroded into an adjacent artery, causing bleeding. A stone at the ampulla of Vater apparently served as a ball valve to prevent massive hemorrhage. We discuss the pathogenesis of hemobilia in chronic pancreatitis and suggested therapy.

Biliary Tract Diseases

Fertility of dairy cattle after artificial insemination with semen frozen in a lipoprotein diluent.

A lipoprotein separated from egg yolk by centrifugation and column chromatography was used to prepare a diluent containing 2-9% trisodium citrate. 2H2O (pH 7-0) and 7% glycerol. Ejaculates from Friesian bulls were split between this and two control diluents containing egg yolk, glycerol and citrate or lactose and used to inseminate once 1782 unselected Friesian cows. By 16 weeks after insemination with semen frozen in the egg yolk-lactose, egg yolk-citrate or lipoprotein-citrate diluents, 66-4, 67-1 and 66-1% of cows, respectively, had not returned to service.

Animals

The relationship between semen evaluation methods and fertility in the bull.

The results are presented of two experiments in which the quality of samples of bull semen was assessed by a number of laboratory tests and then correlated with the 112-day non-return percentage obtained by the use of those samples in A.I. The results reveal the inadequacy of the laboratory tests used as methods of predicting the fertility of semen samples but show that limits may be set outside which poor semen samples could be discarded.

Animals