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Biomedical subjects

J G Davis

Publications and source records attributed to J G Davis.

At least 73 records · Page 4Linked to original sources
PubMed1983

Radiation exposure and associated risks to operating-room personnel during use of fluoroscopic guidance for selected orthopaedic surgical procedures.

Because of the increased use of fluoroscopic guidance techniques in certain orthopaedic surgical procedures, surgeons and other operating-room personnel who are involved in these procedures are voicing growing concern over possible associated radiation health hazards. Using thin-layer lithium fluoride chips for thermoluminescence dosimetry, we directly measured the radiation exposure encountered by the primary surgeon during seven operative procedures that were done utilizing fluoroscopic guidance techniques. Dosimetry studies were also carried out using a tissue-equivalent phantom model to determine the directions of maximum scatter radiation. These studies indicated that the standard protective apron that is commonly worn during the use of fluoroscopy provides adequate protection to most of the body; however, the surgeon is exposed to significant levels of scatter radiation to the head, neck, and hands, Dosimetry studies showed that positioning the fluoroscopic beam vertically to the fracture site of the supine patient, with the x-ray source posterior to the patient, provided the lowest levels of scatter radiation to the surgeon in the normal working position.

Fluoroscopy↗
PubMed1980

Incidence of chromosomal rearrangements in couples with reproductive loss.

We report on 50 couples with reproductive loss did not have any detectable chromosome abnormality. A history of a previous child with multiple congenital abnormalities may be significant in identifying couples with a structural rearrangement. Only by studying more families can this hypothesis be tested. Studies of abortus tissue reveal a high percentage of chromosome abnormalities but a very low incidence of unbalanced translocations. Cytogenetic studies are indicated in a couple which has a past history of spontaneous abortions and a previous child with multiple congenital anomalies.

Abnormalities, Multiple↗
PubMed1980

A liveborn case of 49,XXXY, + 18.

The first case of a liveborn male infant trisomic for both the X and the No 18 chromosome is presented. The patient had multiple congenital anomalies many of which were similar in appearance to patients with trisomy 18. The proband died after 2 days. Both maternal and paternal karyotypes were normal.

Abnormalities, Multiple↗
PubMed1979

Inhibition of degradation of insulin by ophthalamic acid and by a bovine pancreatic proteinase inhibitor.

We have previously observed that, on subcutaneous administration, a significant proportion of insulin is degraded at the site of injection. The present paper reports that the degradative activity of slices of rat adipose tissue can be inhibited in vitro by ophthalmic acid, a natural analogue of glutathione, and by bovine pancreatic proteinase inhibitor, whereas it is increased by the addition of reduced glutathione.

Adipose Tissue↗
PubMed1979

Prenatal diagnosis of trisomy 20 mosaicism.

Three cases of trisomy 20 mosaicism in amniotic fluid cell cultures are described. Two of the pregnancies resulted in normal full-term infants. The third pregnancy was terminated and revealed a phenotypically normal fetus. A review of five previously reported cases is presented. Explanations of these findings include in vitro nondisjunction, culture of extraembryonic tissue, and true fetal mosaicism. The diagnostic dilemma this presents is discussed.

Adult↗
PubMed1977

De novo trisomy 9pter leads to q13.

A case of de novo trisomy 9p was observed. Cytogenetic analysis of G-, R-, Q-, and C-banded preparations revealed a karyotypic description of 47,XY,+del(9)(pter leads to q13). In addition to the principal characteristics of the 9p trisomy syndrome, the child presented with skeletal and urogenital abnormalities. It appears that certain clinical abnormalities are due to trisomy of 9q1.

Abnormalities, Multiple↗
PubMed1977

The high-risk perinatal registry. A systematic approach for reducing perinatal mortality.

A systematic and comprehensive review of all 320 perinatal deaths occurring in Nassau County in 1973 reveals that one-quarter of these deaths might have been prevented if modalities of care that were known and available at that time had been utilized appropriately. Preventability--the presence or absence of avoidable factors which might have materially lessened the risk of death --was determined for each perinatal death. Preventable deaths were disproportionately higher among postmature (P less than .01) and large-for-gestational-age (P less than .05) perinatal deaths, neonatal deaths after the first day of life (P less than .05), intrapartum fetal deaths (P less than .01), and perinatal deaths secondary to anoxia and idiopathic respiratory distress syndrome (P less than .01). The study concludes that rigorous application of currently available medical knowledge, the establishment of local perinatal mortality review committees, and vigorous outreach to practitioners are urgently needed to bridge the time gap between the development of new modalities of care and their application.

Adult↗
PubMed1976

A child with presumptive monosomy 21 (45,XY,-21) in a family in which some members are Gq-.

Presumptive monosomy for chromosome 21 was found in a male child with multiple malformations and severe psychomotor retardation. Chromosome analyses of cells from blood and skin samples were performed at intervals during the first few years of his life. In preparations stained with nonbanding was well as quinacrine, Giemsa, and reverse acridine orange banding techniques, only one No. 21 chromosome could be detected with no apparent abnormalities of the other chromosomes. The proband's phenotypically normal father, paternal grandfather, brother, and paternal aunt have a deletion for a short segment of the long arm of a G-group chromosome. Genetic-marker studies allow the exclusion of a number of blood groups as being associated with No 21. There is inconclusive evidence suggesting that expression of the Duffy blood group, which has been mapped to chromosome 1, may be influenced by genetic information on chromosome 21. This family is of potential value for further gene-mapping studies.

Abnormalities, Multiple↗