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Biomedical subjects

J F Hasler

Publications and source records attributed to J F Hasler.

At least 37 records · Page 2Linked to original sources
PubMed1992

Current status and potential of embryo transfer and reproductive technology in dairy cattle.

Significant use of embryo transfer in dairy cattle commenced with the introduction of nonsurgical embryo recovery in the mid-1970s and developed with the use of nonsurgical transfers in the late 1970s. Numbers of registered Holstein calves from embryo transfer doubled yearly through 1980, after which the rate of increase slowed; the total reached nearly 19,000 calves in 1990. However, the efficacy of superovulation procedures and commercial success rates of transferred fresh embryos have not improved the past 10 to 15 yr. Fertilization rates in superovulated donors remain low. Although embryo-splitting techniques were perfected in the early 1980s, they are not used widely. A practical, commercial embryo-sexing procedure remains unavailable. Recent significant improvement is apparent in the technology of ultrasound-guided oocyte collection and in vitro oocyte maturation, fertilization, and embryo culture. In the future, this technology may be used in conjunction with sperm separated by sex with a flow cytometer. Modest numbers of embryo clones have been produced in several commercial programs via nuclear transfer techniques. However, the efficiency of gene transfer experiments involving ova of cattle and other domestic species has been low. Recently, DNA probe technology has begun to provide genotype information for cattle and will ultimately be applied to embryos.

Animals↗
PubMed1987

Occult radiopaque jaw lesions in familial adenomatous polyposis coli and hereditary nonpolyposis colorectal cancer.

The purposes of this study were to determine the association, in 10 pedigrees, between adenomatous polyposis coli, hereditary nonpolyposis colorectal cancer, and occult radiopaque jaw lesions, and to assess whether these radiodensities are predictors for adenomatous polyposis. In seven kindreds with adenomatous polyposis, all patients with polyps had jaw lesions; in one kindred, no jaw lesions were found. In one of two kindreds with hereditary nonpolyposis colorectal cancer, no affected individuals had jaw lesions. In the other, the 1 affected patient with dental radiographs had generalized jaw lesions. Twelve children less than 16 yr old at risk for adenomatous polyposis were observed. Seven children with jaw lesions developed polyps after a mean interval of 4 yr. Five children without jaw lesions were polyp-free during a 5-10-yr follow-up. Thus, occult jaw lesions are consistently found only in some families with adenomatous polyposis coli, providing support for heterogeneity in polyposis syndromes. Jaw lesions are good predictors for polyp development in kindreds with adenomatous polyposis coli and jaw lesions. Their role as markers in hereditary nonpolyposis colorectal cancer needs exploration.

Adenomatous Polyposis Coli↗
PubMed1986

The isolation of fungi from laboratory dental pumice.

Samples of used dental laboratory pumice from the two dental laboratories were cultured for the isolation of fungi. The resulting supernatant fluid from sedimentation of each pumice sample after suspension in sterile saline was serially diluted and plated onto Sabouraud agar. After incubation, fungal colonies observed were enumerated, isolated, and identified. The mean number of fungal colonies recovered from 10 pumice samples in laboratories I and II was 51.0 X 10(2) and 22.6 X 10(2), respectively. In both laboratories the predominant fungi recovered were Aspergillus niger and Fusarium sp. Other fungi recovered included Cephalosporium and Penicillium species and A. flavus. Many of these organisms have been involved in human disease. It is suggested that the presence of fungi in used dental laboratory pumice presents an unhygienic condition in the dental laboratory and may place dental laboratory technicians and denture patients at increased risk of fungal sensitization and disease.

Aspergillus niger↗
PubMed1985

Comparative fertility of normal and repeat-breeding cows as embryo recipients.

Morphologically normal embryos were transferred surgically into uteri of normal and repeat-breeder cows at seven days post-estrus to compare embryo survival rates in the two kinds of cows. All cows were less than ten years of age and had no abnormal genital discharges, cystic ovarian follicles, or anatomical abnormalities of the reproductive tract. Normal cows had not been inseminated after last calving. Repeat-breeders had at least four infertile services within the past six months (average of 6.2 services after calving). To test fertility of repeat-breeders at synchronized estrus, 22 anatomically-normal repeat-breeders were treated by intramuscular (i.m.) injection with prostaglandin F(2)alpha (PGF(2)alpha) on day 11 of an estrous cycle (estrus = day 0) and inseminated at induced estrus; 11 cows (50%) had a normal fetus at necropsy on day 60. Twenty-three repeat-breeders and 23 normal cows were assigned as embryo recipients and treated i.m. with PGF(2)alpha to synchronize estrus. All embryo donors were normal cows. Donors were treated with FSH and PGF(2)alpha and inseminated at estrus. On day 7 after estrus, embryos were recovered nonsurgically from donors and one embryo was transferred through a flank incision to the anterior end of the uterine horn adjacent to the corpus luteum of each recipient. Recipients that did not return to estrus were necropsied at day 60. Of 28 normal and 23 repeat-breeder recipients, 23 normal cows (82%) and 16 repeat breeders (70%) were pregnant at day 60 (P=0.235). Thus, at seven days post-estrus, the maternal environment of most of these repeat-breeders was satisfactory for maintaining pregnancy.

Journal Article↗
PubMed1983

Searching for markers in the hereditary intestinal polyposes.

Oral abnormalities in the intestinal polyposes have been reported by numerous authors. Detection of occult osteomatous and other dental changes in the jaws before development of polyps would be of considerable importance in the early diagnosis of premalignant gastrointestinal disorders. More than 425 individuals from families in whom intestinal polyposis is segregating have received oral-facial examinations. The dental findings may permit early, noninvasive identification of individuals at risk for polyposis.

Adolescent↗
PubMed1983

Acinetobacter contamination of laboratory dental pumice.

Micro-organisms of the genus Acinetobacter, implicated as opportunistic pathogens, have been recovered from dentures after laboratory repair. A study was undertaken to determine if Acinetobacter could be isolated from used dental pumice. Cultural studies demonstrated that Acinetobacter calcoaceticus variety lwoffi was present in high numbers in used pumice and was a major gram-negative microbial contaminant.

Acinetobacter↗
PubMed1982

Parotid enlargement: a presenting sign in anorexia nervosa.

The purpose of this article is to present the pertinent medical and dental features of anorexia nervosa and to add an additional oral-facial finding, parotid gland enlargement, which has been described infrequently in a few scattered reports. Pertinent differential diagnoses for the systemic and oral-facial findings are discussed, including a review of the factors producing salivary gland enlargement. Early recognition of the psychiatric and pathophysiologic components of this disorder are essential to diagnosis and successful treatment. The dentist should consider the diagnosis of anorexia nervosa in the presence of such abnormal dental findings as perimylolysis and chronic salivary gland enlargement, especially in underweight and amenorrheic young women.

Adolescent↗
PubMed1982

Milk progesterone concentration and production in superovulated Holstein cows.

Six Holstein cows in a commercial herd (three superovulated and three controls) and eight Holstein cows superovulated a total of 12 times in an experimental herd were studied. Superovulation was induced primarily by treatment with follicle stimulating hormone and prostaglandin F2 alpha. Milk was weighed twice daily for 30 days following treatment in the commercial herd with no effect on production. Milk samples were saved on Monday, Wednesday, and Friday to determine progesterone content. Last milk at mid-cycle averaged 8.2 ng/ml of progesterone for the cows in the experimental herd, and 7 days after superovulation they averaged 52.6 +/- 10.2 ng/ml (mean +/- standard error) of progesterone. The correlation with number of embryos recovered was .86. Therefore, milk progesterone may be useful in monitoring superovulatory response. Also, injection of prostaglandin F2 alpha into superovulated cows 9 days after a previous injection did not initiate a new estrous cycle, a fact accurately monitored by milk progesterone determinations.

Animals↗
PubMed1982

Resolved: that a fifth year of dental education be a requirement. Remarks for the affirmative.

Evidence has been presented that leading deans of dental schools and leaders of the AADS support the assertion that the current four-year dental curriculum is overcrowded. Furthermore, it has been shown that the magnitude of the problem of overcrowding is regarded as serious and has been so recognized for at least twenty years. Evidence was also presented that educators, students, and the practicing profession support the assertion that the current four-year curriculum does not prepare students adequately for dental practice. Evidence was then presented that the overcrowding and inadequacies of the current curriculum cannot be corrected by merely manipulating or restructuring curricular elements within the context of predental and four years of predoctoral education. Finally, it was shown that, in the opinion of educators and students, the overcrowding and inadequacies of the current four-year curriculum can be overcome by establishing a fifth year of dental education as a requirement.

Clinical Competence↗