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Biomedical subjects

B D Barnett

Publications and source records attributed to B D Barnett.

At least 19 recordsLinked to original sources
PubMed1998

Spontaneous rupture of a primigravid uterus secondary to placenta percreta. A case report.

BACKGROUND: Uterine rupture secondary to placenta percreta has been observed in multiparous patients. These cases are typically associated with a prior history of uterine trauma or infection: hysterotomy, myomectomy, cornual resection, dilatation and curettage, manual removal of the placenta or endometritis. Spontaneous rupture of the primigravid uterus without a history of trauma or infection is an exceedingly rare occurrence. This case represents the second reported in the medical literature and the first to result in a live-born infant. CASE: A 23-year-old, African American primigravida at 26 weeks' gestation presented with acute-onset abdominal pain, severe hypotension, tachycardia and fetal heart rate decelerations. Blood product replacement was initiated, and an emergency laparotomy was performed for a presumptive diagnosis of intraabdominal hemorrhage. A significant hemoperitoneum was encountered, with the fetus floating freely in the peritoneal cavity. The uterus had a fundal rupture with a clinically apparent placenta percreta that necessitated performing a total abdominal hysterectomy. The patient recovered uneventfully, and the infant survived without significant morbidity. CONCLUSION: Spontaneous rupture of the primigravid uterus can occur in the absence of a history of uterine trauma or infection. If a gravid woman presents with hypotension, abdominal pain and fetal distress, the differential diagnosis should include rupture of the uterus, regardless of parity or gynecologic history. Rapid diagnosis, blood product replacement and emergency laparotomy are the key steps in successful management.

Abdominal Pain↗
PubMed1990

Mechanism of insect resistance to the microbial insecticide Bacillus thuringiensis.

Receptor binding studies show that resistance of a laboratory-selected Plodia interpunctella strain to a Bacillus thuringiensis insecticidal crystal protein (ICP) is correlated with a 50-fold reduction in affinity of the membrane receptor for this protein. The strain is sensitive to a second type of ICP that apparently recognizes a different receptor. Understanding the mechanism of resistance will provide strategies to prevent or delay resistance and hence prolong the usefulness of B. thuringiensis ICPs as environmentally safe insecticides.

Animals↗
PubMed1990

Resistance to Bacillus thuringiensis by the Indian meal moth, Plodia interpunctella: comparison of midgut proteinases from susceptible and resistant larvae.

Midgut homogenates from susceptible and resistant strains of the Indian meal moth, Plodia interpunctella, were compared for their ability to activate the entomocidal parasporal crystal protein from Bacillus thuringiensis. The properties of midgut proteinases from both types of larvae were also examined. Electrophoretic patterns of crystal protein from B. thuringiensis subspecies kurstaki (HD-1) and aizawai (HD-133 and HD-144) were virtually unchanged following digestion by either type of midgut homogenate. Changes in pH (9.5 to 11.5) or midgut homogenate concentration during digestion failed to substantially alter protein electrophoretic patterns of B. thuringiensis HD-1 crystal toxin. In vitro toxicity of crystal protein activated by either type of midgut preparation was equal toward cultured insect cells from either Manduca sexta or Choristoneura fumiferana. Electrophoresis of midgut extracts in polyacrylamide gels containing gelatin as substrate also yielded matching mobility patterns of proteinases from both types of midguts. Quantitation of midgut proteolytic activity using tritiated casein as a substrate revealed variation between midgut preparations, but no statistically significant differences between proteolytic activities from susceptible and resistant Indian meal moth larvae. Inhibition studies indicated that a trypsin-like proteinase with maximal activity at pH 10 is a major constituent of Indian meal moth midguts. The results demonstrated that midguts from susceptible and resistant strains of P. interpunctella are similar both in their ability to activate B. thuringiensis protoxin and in their proteolytic activity.

Animals↗
PubMed1985

Chemical vasectomy of domestic dogs in the Galapagos islands.

A field test of a previously reported technique for chemically vasectomizing male dogs was performed on Floreana Island in the Galapagos Archipelago. Injection of 0.5 ml of a 4.5% aqueous solution of chlorhexidine digluconate into each tail of the epididymides of seven test animals resulted in azoospermic ejaculates by day 35 after treatment. This azoospermia was persistent for the remainder of the test period and through the fourth month after injection. No changes in ejaculate volume or semen pH occurred with the treatment although a slight, transitory swelling of the testes was observed. A large-scale application of this method was initiated in the Galapagos under the authority of the National Park Service and appears to be a practical technique for reproduction control in domestic dog populations.

Journal Article↗
PubMed1981

Effects of varying chamber construction and embryo pre-incubation age on survival and growth of chick embryos in shell-less culture.

Shell-less culture involves culturing chick embryos with associated yolk and albumen outside of the eggshell and shell membranes. The technique allows direct access to and continuous observation of cultured embryos almost to the time of hatching. The plastic wrap/culture tripod technique described in this paper allows normal embryonic growth and differentiation from 48 hours (in ovo pre-incubation age) through at least 10 days of total incubation. As the duration of in ovo pre-incubation is decreased below 36 hours, there is a concomitant increase in the percentage of grossly abnormal embryos associated with decreased survival and retarded growth and differentiation. Survival of embryos pre-incubated for 72 hours through 13 and 18 days of total incubation is greater than 80% and 40%, respectively. The wrap/tripod technique allows substantially better survival and more normal development of cultured embryos than does the petri dish technique of Auerbach et al. (1974). Embryonic growth in 7.8-cm-diameter chambers is significantly greater than in either larger (10.6 cm) or smaller (5.2 cm) diameter chambers. Some gas exchange through the culture chamber walls appears necessary for optimal embryonic survival and growth. Suspending egg contents in either Safeway or Handi-Wrap plastic wrap (both of intermediate permeability) in 7.8-cm tripods resulted in superior growth and/or survival compared to suspension in Silastic sheeting (high permeability), Saran Wrap (low permeability), glass dishes (nonpermeable), or glass dishes lined with an inner layer of Safeway wrap(nonpermeable).

Animals↗
PubMed1977

The effect of pokeberry ingestion on immune response in turkeys.

The experiments were conducted to determine the effect of pokeberry ingestion on immune response in turkeys. In the first experiment, addition of pokeberries to a control diet at levels of 2.5% or 5.0% had no significant effect on feed consumption or production or sheep's red blood cell (SRBC) antibodies. In the second experiment, drenching with a pokeberry suspension had no significant effect on production of SRBC antibodies.

Agglutination Tests↗
PubMed1976

The effect of protein and dietary energy levels and housing regime on production and reproduction parameters of turkey hens.

Two experiments were conducted using 960 Large Board Breasted White turkey hens to measure the effect of diet and confinement housing versus range pens on egg production, fertility and hatchability. A 2 X 3 factorial arrangement of diets provided protein levels of 15 and 18% with metabolizable energy levels of 2666, 2893, and 3101 kcal. per kg. of diet. The hens were randomized into 24 range pens and 24 pens in an open-sided house. Dietary protein levels had no effect on body weight, feed consumption, egg production, fertility or hatchability. Hens fed the higher energy diet produced larger eggs (P less than .05), but there was no difference in total egg production due to dietary energy level. As dietary energy level increased, feed consumption linearly decreased. Hens fed the 3102 kcal./M.E./kg. diet had significantly higher fertility (P less than .05) than hens fed the intermediate energy level diet with no differences between the lowest energy level and either of the other two levels. Fertile eggs from hens fed the intermediate energy level diet had lower hatchability (P less than .05) than those from hens fed either the lower or higher dietary energy levels. Type of housing and no effect on average body weight or feed consumption on a hen-day basis. Housing treatment had no effect on percent fertility or hatchability. Hens housed in the range pens produced more and larger eggs (P less than .05) and more eggs per kg. of feed than hens penned in the house.

Animals↗
PubMed1976

Response of chicks and turkey poults to Aroclor 1242.

Diets containing equal amounts of Aroclor 1242 contaminated fish meal were fed to chicks and poults from day-old to four weeks. Four levels from 0 to 10% of contaminated fish meal having 1500 p.p.m. PCB's were used, supplying 0, 38, 75 p.p.m. gained 432 g. and had 21% mortality, and 150 p.p.m. gained 338 g. and had 75% mortality. Chicks performed as follows: controls gained 504 g. and had 4% mortality, 38 p.p.m. PCB gained 481 g. and had 2% mortality, 75 P.P.M. gained 432 G. and had 21% mortality, and 150 P.P.M gained 338 G. and had 75% mortality. Chicks receiving 75 and 150 p.p.m. PCB were lighter in weight (P less than 0.05) than the 0 and 38 p.p.m. levels. The 150 p.p.m diet produced higher (P less than 0.05) mortality than the lower levels. Both 75 and 150 p.p.m. diets produced edema and other lesions attributed to PCB toxicity. Poults receiving the same treatment gained 386 g., 386 g., 389 g., and 387 g. respectively . Mortality was heavy due to a possible bacterial infection early in the brooding. No mortality was attributed to PCB toxicity. Post mortem showed no edema, pericarditis, or other lesions due to PCB toxicity. Another trial was run on poults using the 0 and 150 p.p.m. levels. The growth results were almost identical. Mortality was very low. The 0 treatment gained 616 g. and the 150 p.p.m. treatment 613 g. There were no apparent PCB toxicity symptoms or lesions in these poults.

Animals↗
PubMed1975

Toxicity of pokeberries (fruit of Phytolacca americana large) for turkey poults.

Fresh pokeberries were picked from the cluster and liquified in a blender for 3 to 5 minutes. The liquified berries were mixed into a standard turkey starter at the rate of 0, 2-1/2, 5 and 10%. Addition was at the expense of the total diet. Two separate experiments were conducted with day old Broad White turkeys. Weight gain, mortality and gross lesions were observed to 3 weeks of age. Growth rate was reduced with each increase in level of pokeberries. In Experiment 1, 3-week gains were 376, 354, 314 and 205 g. for 0, 2-1/2, 5 and 10% pokeberries. Weight gains in Experiment 2 were 339, 317, 254 and 172. Mortality was 33 and 43% in the two experiments when 10% pokeberries were fed. Lower levels produced erratic mortality results. Poults fed 5 and 10% pokeberries exhibited ataxia and occasional inability to walk. The hock joints frequently became enlarged and crooked. Ascites was observed in some birds at all dietary levels of added pokeberries. The gall bladder of dead birds was frequently much enlarged and filled with brownish fluid rather than normal bile.

Animals↗