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Biomedical subjects

J C Kelly

Publications and source records attributed to J C Kelly.

At least 19 recordsLinked to original sources
PubMed1996

Sex ratios in fetuses and liveborn infants with autosomal aneuploidy.

Ten data sources were used substantially to increase the available data for estimating fetal and livebirth sex ratios for Patau (trisomy 13), Edwards (trisomy 18), and Down (trisomy 21) syndromes and controls. The fetal sex ratio estimate was 0.88 (N = 584) for trisomy 13, 0.90 (N = 1702) for trisomy 18, and 1.16 (N = 3154) for trisomy 21. All were significantly different from prenatal controls (1.07). The estimated ratios in prenatal controls were 1.28 (N = 1409) for CVSs and 1.06 (N = 49427) for amniocenteses, indicating a clear differential selection against males, mostly during the first half of fetal development. By contrast, there were no sex ratio differences for any of the trisomies when comparing gestational ages < 16 and > 16 weeks. The livebirth sex ratio estimate was 0.90 (N = 293) for trisomy 13, 0.63 (N = 497) for trisomy 18, and 1.15 (N = 6424) for trisomy 21, the latter two being statistically different than controls (1.05) (N = 3660707). These ratios for trisomies 13 and 18 were also statistically different than the ratio for trisomy 21. Only in trisomy 18 did the sex ratios in fetuses and livebirths differ, indicating a prenatal selection against males > 16 weeks. No effects of maternal age or race were found on these estimates for any of the fetal or livebirth trisomies. Sex ratios for translocations and mosaics were also estimated for these aneuploids. Compared to previous estimates, these results are less extreme, most likely because of larger sample sizes and less sample bias. They support the hypothesis that these trisomy sex ratios are skewed at conception, or become so during embryonic development through differential intrauterine selection. The estimate for Down syndrome livebirths is also consistent with the hypothesis that its higher sex ratio is associated with paternal nondisjunction.

Adult↗
PubMed1993

The effect of ion implantation on cellular adhesion.

As there are only a finite number of materials suitable for orthopaedic reconstruction, considerable effort has been devoted recently to investigating ways of altering the surface chemistry of prosthetic materials without altering their bulk properties. Ion beam implantation is one such technique which is appropriate for orthopaedic reconstructive materials. This paper investigates the early effect of ion beam modification on cellular attachment of bone derived cells using a prototype device which measures the strength of attachment of individual cells to a silicon substratum. The results point to several conclusions. (1) There is no evidence that ion beam implantation with nitrogen, phosphorus, manganese or magnesium produces increased adhesion of human bone derived cells. (2) Surface etching with hydrofluoric acid, electron bombardment and thermal oxidation increases the strength of attachment between cells and substrata. (3) There is a correlation between wettability and rate of cellular attachment to oxygen implanted substrata during the first 2 h after cellular seeding. However, the increase in cellular attachment cannot be entirely explained by the change in critical surface tension or via increased fibronectin attachment to the substrata.

Bone Transplantation↗
PubMed1990

Second trimester maternal serum pregnancy specific beta-1 glycoprotein (SP-1) levels in normal and Down syndrome pregnancies.

Maternal serum pregnancy specific beta-1 glycoprotein (SP-1) levels in the second trimester may be predictive of Down syndrome (DS). An enzyme immunoassay was used to measure SP-1 sera from 46 DS pregnancies and 117 normal control women matched for maternal age, gestational age, and length of storage. In the normal control samples, there were slight correlations between the SP-1 concentration and maternal age. The maternal serum SP-1 levels increased with each week of gestation from 15 to 20 weeks. All but one of the DS sera had SP-1 levels greater than the normal median. Using a cutoff of 2.8 multiples of the median (MoM), 15.2% of the DS pregnancies were detected with a false-positive rate of 4.3%. A combinational logistic regression analysis of maternal age and pregnancy related serum proteins will detect additional DS pregnancies and decrease the false-positive rate. The combination of maternal age and SP-1 detected 33 (71.7%) of Down syndrome pregnancies. The addition of maternal serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) levels allowed for the detection of 36 (78.3%) of the DS pregnancies with a decrease in the false-positive rate to 3.4%. The measurement of other serum constituents in conjunction with AFP appears to be a valuable addition to current screening programs, as this can increase the proportion of DS cases detected prenatally.

Adolescent↗
PubMed1990

Chloroquine poisoning in a child.

Chloroquine poisoning in children, although infrequent, is extremely dangerous because of the narrow margin between therapeutic and toxic doses. Children clinically present with apnea, seizures, and cardiac arrhythmias. We present the case of a 12-month-old infant, the second-youngest patient reported in the US literature to die from chloroquine poisoning. A serum level of 4.4 mg/L (13.64 mumol/L) was obtained after the infant ingested only one tablet (300 mg). This establishes a new minimal lethal dose/blood level for children. Although some pediatric and adult pharmacokinetic and clinical similarities exist, the outcome is different. Pediatric mortality is 80%, whereas adult mortality is only 10%. Pediatric ingestion cases are primarily unintentional, and most adult cases are suicide attempts. Current treatment in adults includes a protocol of diazepam and epinephrine. Further studies involving children and these medications and other modalities are needed to improve survival.

Apnea↗
PubMed1989

Amniotic fluid acetylcholinesterase ratios in prenatal diagnosis of fetal abnormalities.

This study examined 141 pregnancies with acetylcholinesterase in the amniotic fluid to determine if an acetylcholinesterase/pseudocholinesterase ratio cutoff could be set to distinguish between neural tube defects, ventral wall defects, other fetal defects, and pregnancy problems. Amniotic fluid specimens with positive or faintly positive acetylcholinesterase bands were studied. They were scanned and analyzed for the acetylcholinesterase/pseudocholinesterase ratio. In 62 of 65 fluid samples from open neural tube defects, the acetylcholinesterase/pseudocholinesterase ratios were greater than 0.13. All cases with ventral wall defects (n = 29), fetal blood contamination (n = 16), or fetal ascites (n = 2) had acetylcholinesterase/pseudocholinesterase ratios less than 0.13. Samples of cystic hygroma fluid (n = 10) had acetylcholinesterase/pseudocholinesterase ratios greater than 0.13. Two patients with fetal teratomas had intermediate values. All patients with normal outcomes but positive acetylcholinesterase had ratios of less than 0.12. Acetylcholinesterase/pseudocholinesterase ratios are a valuable part of a prenatal program to accurately diagnose fetal abnormalities.

Acetylcholinesterase↗
PubMed1989

Prenatal screening for Down syndrome with maternal serum human chorionic gonadotropin levels.

Human chorionic gonadotropin levels in midtrimester pregnancies may be predictive of Down syndrome. A commercially available enzyme immunoassay kit was used to measure the beta-subunit of human chorionic gonadotropin in maternal sera from 38 Down syndrome pregnancies and 114 gestational age matched controls. The human chorionic gonadotropin levels were also assayed in 236 normal sera and plasma samples to determine normative values and appropriate individual corrections. Serum and plasma human chorionic gonadotropin levels are closely correlated and are stable at room temperature, during refrigeration, and throughout freeze-thaw cycles. There is no correlation between the human chorionic gonadotropin level and maternal age, weight, or race. However, the human chorionic gonadotropin level decreases with each week of gestation from 15 to 19 weeks. Medians for each week of gestation were established to account for this variable. Up to 63% of the Down syndrome pregnancies were detected with a cutoff of 2.0 multiples of the normal median. A computational combination of human chorionic gonadotropin and maternal serum alpha-fetoprotein testing will detect additional Down syndrome pregnancies and decrease the false-positive rate. The measurement of human chorionic gonadotropin appears to be a valuable addition to maternal serum alpha-fetoprotein screening programs that can significantly increase the proportion of Down syndrome cases diagnosed.

Blood Specimen Collection↗
PubMed1987

Vascular basis for neural tube defects: a hypothesis.

A hypothesis is set forth that neural tube defects are produced by inadequate nutrient supply to the rapidly growing neural folds. According to this hypothesis, a delay in establishing blood flow or an aberration of blood supply to neural tissue may interfere with nutrition and prevent neural tube closure. The hypothesis was tested by examining the vasculature of fetuses with spinal neural tube defects. In each case, the arterial supply to the region of the neural tube defect was disturbed. Because development of arterial supply to the neural folds predates neural tube closure, these vascular abnormalities are considered to be primary malformations that lead to neural tube defects rather than secondary morphologic disturbances resulting from neural tube defects.

Blood Vessels↗
PubMed1986

The prophylactic use of phenytoin during iopamidol contrast studies of the subarachnoid space.

Contrast examinations of the subarachnoid space are associated with side effects including convulsions. Attention has been given to the prophylactic use of anticonvulsants. We describe a simple oral regimen using the established anticonvulsant phenytoin that can be administered to short-stay patients and that achieves effective serum and CSF concentrations. A preliminary account of this work was presented to the British Pharmacological Society in January 1984 in London.

Contrast Media↗
PubMed1979

Glycine transport by human diploid fibroblasts--absence of a defect in cells from patients with nonketotic hyperglycinemia.

Glycine transport in human diploid fibroblasts was shown to be by a single sodium-dependent system. Glycine transport does not appear to exhibit transstimulation or transinhibition. Transport appears to be similar to the A transport system of other mammalian cell lines, as defined by competition patterns. Normal and nonketotic hyperglycinemia (NKH) fibroblasts could not be distinguished on the basis of accumulation or initial rates. A distribution ratio of 15 to 30 was reached by both types of cells. The normal lines have slightly lower apparent Kms (1.1-1.3 mM) than the NKH lines (1.8 to 2.4 mM). The values for the Vmax of the normal cells (11.4-12.9 nmole/mg/min) and the NKH cells (7.0-16.7 nmole/mg/min) overlapped. There were no measurable differences in either the long-term incorporation into protein of leucine and glycine or the oxidation of glycine in normal and NKH fibroblasts.

Biological Transport↗
PubMed1977

Membrane function in cystic fibrosis. I. Putrescine transport in normal and cystic fibrosis fibroblasts.

Putrescine transport was examined in normal and cystic fibrosis fibroblasts. No differences were observed in accumulation pattern, kinetics of uptake, or efflux between CF and normal cells. In both growing and growth-arrested CF and normal fibroblasts, exogenously supplied putrescine remained unchanged for at least 60 min. Some differences were observed in the response of CF and normal cells to environmental (media) changes.

Biological Transport↗
PubMed1977

Membrane function in cystic fibrosis. II. Methionine transport in normal and cystic fibrosis fibroblasts.

Initial rate kinetics of methionine transport, time course of accumulation of methionine, and efflux of accumulated methionine were studied in three normal and four CF human diploid fibroblast strains. The range of apparent Km's was 12.7-32.1 micrometer for the CF strains and 18.3-39.2 micrometer for the normal strains. The range of apparent Vmax's was 6.69-9.22 nmole mg-1 min-1 for the CF strains and 5.59-7.87 nmole mg-1 min-1 for the normal strains. The patterns of accumulation and efflux are quite similar in all the strains studied except for WI-38, which showed somewhat higher efflux and lower accumulation than for others. There was no significant difference in the kinetic parameters of methionine transport between CF and normal skin fibroblasts, and methionine transport will not serve as a marker for cystic fibrosis in cultured fibroblasts.

Biological Transport, Active↗