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Biomedical subjects

J M Hayes

Publications and source records attributed to J M Hayes.

At least 91 records · Page 5Linked to original sources
PubMed1992

Diploptene: an indicator of terrigenous organic carbon in Washington coastal sediments.

The pentacyclic triterpene 17 beta(H),21 beta(H)-hop-22(29)-ene (diploptene) occurs in sediments throughout the Columbia River drainage basin and off the southern coast of Washington state in concentrations comparable to long-chain plantwax n-alkanes. The same relationship is evident for diploptene and long-chain n-alkanes in soils from the Willamette Valley. Microorganisms indigenous to soils and soil erosion are indicated as the biological source and physical process, respectively, for diploptene in coastal sediments. Similarity between the stable carbon isotopic composition (delta 13CPDB) of diploptene isolated from soil in the Willamette Valley (-31.2 +/- 0.3%) and from sediments deposited throughout the Washington coastal environment (-31.2 +/- 0.5%) supports this argument. Values of delta for diploptene in river sediments are variable and 8-17% lighter, indicating that an additional biological source such as methane-oxidizing bacteria makes a significant contribution to the diploptene record in river sediments. Selective biodegradation resulting from a difference in the physicochemical association within eroded particles can explain the absence of the more-13C-depleted form of diploptene in Washington coastal sediments, but this mechanism remains unproven.

Alkanes↗
PubMed1992

Comprehensive orientation: the road to retention.

This study evaluated the relationship between the type of orientation received by registered nurse employees in the hospital and the turnover behavior of these employees within the first 12 months of employment. The comprehensiveness of the orientation programs of six major metropolitan hospitals was evaluated using a structure evaluation tool. The records of registered nurses who attended the September 1988 orientation programs at these hospitals were examined to identify their employment status and pertinent demographic data one year from the date of participation in orientation. Data were analyzed to determine if an association existed between the comprehensiveness of orientation and employment status. The data revealed no significant difference between "stayers" and "leavers" after participation in orientation programs meeting greater than 80 percent of the criteria for program comprehensiveness. Significantly more "leavers" than "stayers" resulted from participation in programs meeting greater than 90 percent of the criteria for program comprehensiveness.

Chi-Square Distribution↗
PubMed1992

Appearance of the hymen in prepubertal girls.

The recent increase in requests for genital examinations in girls who may have been sexually abused has necessitated detailed information not previously available on normal anatomy of the prepubertal girl. This study was undertaken to document the genital anatomy of 211 girls between the ages of 1 month and 7 years who presented for well child care or nongynecologic complaints and who had no history of sexual abuse. Each child's genitalia was examined and photographed, with findings reported reflecting those observed photographically. The study population consisted of 36% blacks, 33.6% white non-Hispanics, 29.9% Hispanics, and 0.5% Asians. Subjects had a mean age of 21 +/- 20.6 (SD) months. Extensive labial agglutination sufficient to obscure the hymen was noted in 5% (10/211) and partial agglutination in an additional 17% (35/211). A significant difference was noted in hymenal configuration by age, with a fimbriated hymen the most common type (46%) in infants aged 12 months or younger and a crescentic hymen the most common (51%) in girls older than 24 months (P less than or equal to .001). No significant difference was noted in hymen configuration by race. Hymenal bumps (mounds) were observed in 7%, hymenal tags in 3%, vestibular bands in 98%, longitudinal intravaginal ridges in 25%, and external ridges in 15% of subjects in whom the anatomy under study could be visualized. Hymenal notches (clefts) occurred superiorly and laterally on the hymenal rim but none were found inferiorly on the lower half of the hymen. A narrow rounded hymenal ring with a transection was observed in only 1 (0.5%) of 201 subjects and was not considered a normal finding.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Isotopic compositions of carbonates and organic carbon from upper Proterozoic successions in Namibia: stratigraphic variation and the effects of diagenesis and metamorphism.

The carbon isotope geochemistry of carbonates and organic carbon in the late Proterozoic Damara Supergroup of Namibia, including the Nama, Witvlei, and Gariep groups on the Kalahari Craton and the Mulden and Otavi groups on the Congo Craton, has been investigated as an extension of previous studies of secular variations in the isotopic composition of late Proterozoic seawater. Subsamples of microspar and dolomicrospar were determined, through petrographic and cathodoluminescence examination, to represent the "least-altered" portions of the rock. Carbon-isotopic abundances in these phases are nearly equal to those in total carbonate, suggesting that 13C abundances of late Proterozoic fine-grained carbonates have not been significantly altered by meteoric diagenesis, although 18O abundances often differ significantly. Reduced and variable carbon-isotopic differences between carbonates and organic carbon in these sediments indicate that isotopic compositions of organic carbon have been altered significantly by thermal and deformational processes, likely associated with the Pan-African Orogeny. Distinctive stratigraphic patterns of secular variation, similar to those noted in other, widely separated late Proterozoic basins, are found in carbon-isotopic compositions of carbonates from the Nama and Otavi groups. For example, in Nama Group carbonates delta 13C values rise dramatically from -4 to +5% within a short stratigraphic interval. This excursion suggests correlation with similar excursions noted in Ediacaran-aged successions of Siberia, India, and China. Enrichment of 13C (delta 13C> +5%) in Otavi Group carbonates reflects those in Upper Riphean successions of the Akademikerbreen Group, Svalbard, its correlatives in East Greenland, and the Shaler Group, northwest Canada. The widespread distribution of successions with comparable isotopic signatures supports hypotheses that variations in delta 13C reflect global changes in the isotopic composition of late Proterozoic seawater. Within the Damara basin, carbon-isotopic compositions of carbonates provide a potentially useful tool for the correlation of units between the Kalahari and Congo cratons. Carbonates depleted in 13C were deposited during and immediately following three separate glacial episodes in Namibia. The correspondence between ice ages and negative delta 13C excursions may reflect the effects of lowered sea levels; enhanced circulation of deep, cold, O2-rich seawater; and/or the upwelling of 13C-depleted deep water. Iron-formation is additionally associated with one of the glacial horizons, the Chuos tillite. Carbon-13 enriched isotopic abundances in immediately pre-glacial carbonates suggest that oceanographic conditions favored high rates of organic burial. It is likely that marine waters were stratified, with deep waters anoxic. A prolonged period of ocean stratification would permit the build-up of ferrous iron, probably from hydrothermal sources. At the onset of glaciation, upwelling would have brought 13C-depleted and iron-rich deep water onto shallow shelves where contact with cold, oxygenated surface waters led to the precipitation of ferric iron.

Carbon↗
PubMed1991

The relative role of neutrophils and platelets in the local accumulation of circulating lymphocytes at sites of ionophore A23187 inoculation.

The early cellular infiltrate at inflammatory sites consists predominantly of neutrophils and cells of the monocyte/macrophage lineage. The mechanism by which circulating, unsensitized lymphocytes accumulate at sites of inflammation is unknown. The pattern of accumulation of 111indium-labeled circulating thymocytes in response to local injections of the ionophore A23187 was studied and compared with the pattern of (125)iodinated albumin accumulation as a measure of vascular permeability. The kinetics of thymocyte accumulation differed from those of vascular permeability. Sublethal total-body irradiation (750 rads) markedly decreased thymocyte accumulation but had little effect on vascular permeability. Irradiation of the local site alone had no effect. T lymphocyte, T lymphoblast, and platelet accumulation generally followed the same pattern as thymocytes. Intravenous injection of neutrophils, but not platelets, partially restored lymphocyte accumulation in vivo in irradiated mice via a pathway involving the circulating neutrophil, and seemed to be independent of changes in vascular permeability.

Animals↗
PubMed1991

Pericarditis following renal transplantation.

We analyzed data on renal allograft recipients over a 27-year period in order to investigate the frequency, etiology, and outcome of pericarditis developing during the first two months following renal transplantation. Of the 1497 patients receiving renal transplants between 1963 and 1990, 34 patients developed 36 episodes of pericarditis and/or pericardial effusions, for an overall incidence of 2.4%. Pericarditis was attributed to uremia in 14 episodes, cytomegalovirus infection in three, both uremia and CMV infection in four, nonspecific bacterial infection in three, and tuberculosis and minoxidil therapy in one episode each. No etiologic diagnosis could be established in 10 episodes. No statistically significant differences were found between pericarditis and case-matched control patients considering demographic features, the number of immediately functioning grafts, the duration of posttransplant acute renal failure, the number of supportive dialysis days, pre- and postoperative CMV status of the patients, and pretransplant BUN and serum creatinine levels. There were more uremic-related complications (pulmonary edema, gastrointestinal bleeding, central nervous system symptoms) in the pericarditis group. Five allografts in the pericarditis group never functioned, versus only one in the control group. Three patients with pericarditis developed pericardial tamponade. Early diagnosis, close follow-up, and in the case of cardiac tamponade early invasive treatment, should improve the prognosis of this potentially life-threatening complication.

Adolescent↗
PubMed1991

Comparison of OKT3 with ALG for prophylaxis for patients with acute renal failure after cadaveric renal transplantation.

A randomized, prospective comparison of OKT3 vs. ALG (University of Minnesota) was performed in patients who had acute renal failure after a cadaver renal transplantation. Criteria for admission to the study were oliguria or increasing serum creatinine in the first 12 hr after renal transplantation. ALG or OKT3 was administered after randomization beginning 12-36 hours posttransplantation. There were no significant differences in age, sex, original disease, ischemia time, or HLA matching between groups. Graft survivals at 1 and 6 months were 84% and 84%, respectively for the ALG group. One- and 6-month graft survival for the OKT3 group was 88% and 84%, respectively. These differences were not statistically significant. The number of rejection episodes and the number of patients with rejection episodes were greater, and the time to first rejection was shorter in the OKT3 group compared with the ALG group, although none of these differences reached statistical significance. There were significantly less side effects in the ALG group compared with the OKT3 group (P less than .05). The greatest reductions in side effects were in fever and hypotension. Patients were monitored with flow cytometry analysis measuring the number of CD2 (T11) and CD3 (T3) cells to adjust the dose of both OKT3 and ALG. Starting doses were 10 mg/kg/day of ALG and 5 mg/day of OKT3. There were no significant differences in the incidence of infections (viral or bacterial) between the two groups. There were no rejection episodes during the prophylactic therapy with either ALG or OKT3. In summary, both ALG and OKT3 provided effective prophylaxis for patients with acute renal failure after renal transplantation. OKT3 was associated with a statistically significant increase in incidence of symptomatic side effects.

Acute Kidney Injury↗
PubMed1991

The development of proteinuria and focal-segmental glomerulosclerosis in recipients of pediatric donor kidneys.

Several reports in animals, and sporadic case reports in humans, have suggested that kidneys with decreased nephron mass may be more susceptible to the development of focal-segmental glomerosclerosis. This prompted a reexamination of our previously reported group of pediatric donor-adult recipient renal transplant combinations. Data were analyzed from 31 adult recipients who had received renal transplants from cadaver pediatric donors (less than 6 years) with graft function for greater than 6 months and no evidence of chronic rejection. These were compared with a control group transplanted during the same period with adult donor kidneys. Immunosuppression consisted of azathioprine/prednisone or quadruple therapy in 16 and 15 patients respectively. End-stage renal disease (ESRD) was secondary to chronic glomerulonephritis (n = 9), diabetes mellitus (n = 6), polycystic kidney disease (n = 5), and miscellaneous causes (n = 11). Twenty patients had radiographic documentation of renal hypertrophy posttransplant. All patients had serial 24-hr urinalysis for protein and creatinine after transplantation during periods of stable renal function. Ten patients had renal biopsies performed at a mean time from transplant to biopsy of 10.4 +/- 1.6 months. Seven recipients had biopsies that revealed glomerulosclerosis at 13 +/- 6 months posttransplant. Protein excretion and serum creatinine in these patients were significantly higher than in control patients (1.6 +/- 0.37 vs. 0.49 +/- 0.15 g/24 hr and 1.96 +/- 0.11 vs. 1.64 +/- 0.09 mg%; P less than 0.03 and P less than 0.01, respectively). Only 3 of 25 control adult donor recipients developed proteinuria greater than 0.8 g/24 hr within 2 years of transplantation vs. 15/31 pediatric donor recipients. No correlations with the etiology of ESRD, age (greater than or less than 40 years), weight, sex, diabetes, hypertension, or the number of acute rejection episodes could be found. Our data suggest that adult recipients of pediatric donor renal transplants may be at greater risk for the development of glomerulosclerosis than those recipients receiving adult donor kidneys.

Adult↗
PubMed1990

A carbon isotope record of CO2 levels during the late Quaternary.

Analyses of gases trapped in continental ice sheets have shown that the concentration of CO2 in the Earth's early atmosphere increased from 180 to 280 p.p.m. during the most recent glacial-interglacial transition. This change must have been driven by an increase in the concentration of CO2 dissolved in the mixed layer of the ocean. Biochemical and physiological factors associated with photosynthetic carbon fixation in this layer should lead to a relationship between concentrations of dissolved CO2 and the carbon isotopic composition of phytoplanktonic organic material, such that increased atmospheric CO2 should enhance the difference in 13C content between dissolved inorganic carbon and organic products of photosynthesis. Here we show that a signal related to atmospheric CO2 levels can be seen in the isotope record of a hemipelagic sediment core, which we can correlate with the CO2 record of the Vostok ice core. Calibration of the relationship between isotope fractionation and CO2 levels should permit the extrapolation of CO2 records to times earlier than those for which ice-core records are available.

Atmosphere↗
PubMed1990

Evidence from carbon isotope measurements for diverse origins of sedimentary hydrocarbons.

The organic matter found in sedimentary rocks must derive from many sources; not only from ancient primary producers but also from consumers and secondary producers. In all of these organisms, isotope effects can affect the abundance and distribution of 13C in metabolites. Here, by using an improved form of a previously described technique in which the effluent of a gas chromatograph is continuously analysed isotopically, we report evidence of the diverse origins of sedimentary organic matter. The record of 13C abundances in sedimentary carbonate and total organic carbon can be interpreted in terms of variations in the global carbon cycle. Our results demonstrate, however, that isotope variations within sedimentary organic mixtures substantially exceed those observed between samples of total organic carbon. Resolution of isotope variations at the molecular level offers a new and convenient means of refining views both of localized palaeoenvironments and of control mechanisms within the global carbon cycle.

Archaea↗
PubMed1990

Primary and diagenetic controls of isotopic compositions of iron-formation carbonates.

Mineralogic, chemical, and isotopic compositions have been determined for 97 carbonate microbands in five core segments from the early Proterozoic (2.5 Ga) Dales Gorge Member of the Brockman Iron Formation, Hamersley Basin, Western Australia. Samples were obtained both from banded iron-formation (BIF) macrobands 9-12 at Paraburdoo, on the southern margin of the basin, and from BIF macroband 13 at Wittenoom, 130 km NW. At Paraburdoo, oxygen-isotopic compositions of coexisting chert and magnetite microbands were measured and indicated final equilibration temperatures ranging from 60-160 degrees C. This range is consistent with observed mineral assemblages and indicates a considerable temperature gradient across the basin (cf. T approximately 300 degrees C at Wittenoom; BECKER and CLAYTON, 1976). Carbon-isotopic compositions of carbonates are near -7% vs. PDB at Paraburdoo and -10.5% at Wittenoom, but the greater isotopic depletion at Wittenoom appears related to primary or diagenetic processes, not metamorphism. Contents of organic carbon are consistently low. Isotopic depletion is roughly correlated with iron abundance and, together with petrographic observations and chemical balances, is consistent with the model of BIF deposition introduced by BEUKES et al. (1990): primary siderite (delta approximately -5%) precipitated from an anoxic water column depleted in 13C; additional depletion of 13C is associated with coprecipitation of iron oxides and organic carbon. Oxygen-isotopic abundances of microbanded carbonates are similar to those under- and overlying massive marine carbonates, ranging from 17.6 to 21.0% vs. SMOW (-9.6 to -12.9% vs. PDB). Millimeter-scale variations in abundances of 13C and 18O are associated with diagenetic replacement of primary siderite by secondary ankerite and/or magnetite. It is shown that these isotopic variations cannot result from mineral-dependent fractionations, metamorphism, or the influence of large volumes of water in an open system.

Carbon↗
PubMed1990

Compound-specific isotopic analyses: a novel tool for reconstruction of ancient biogeochemical processes.

Patterns of isotopic fractionation in biogeochemical processes are reviewed and it is suggested that isotopic fractionations will be small when substrates are large. If so, isotopic compositions of biomarkers will reflect those of their biosynthetic precursors. This prediction is tested by consideration of results of analyses of geoporphyrins and geolipids from the Greenhorn Formation (Cretaceous, Western Interior Seaway of North America) and the Messel Shale (Eocene, lacustrine, southern Germany). It is shown (i) that isotopic compositions of porphyrins that are related to a common source, but which have been altered structurally, cluster tightly and (ii) that isotopic differences between geolipids and porphyrins related to a common source are equal to those observed in modern biosynthetic products. Both of these observations are consistent with preservation of biologically controlled isotopic compositions during diagenesis. Isotopic compositions of individual compounds can thus be interpreted in terms of biogeochemical processes in ancient depositional environments. In the Cretaceous samples, isotopic compositions of n-alkanes are covariant with those of total organic carbon, while delta values for pristane and phytane are covariant with those of porphyrins. In this unit representing an open marine environment, the preserved acyclic polyisoprenoids apparently derive mainly from primary material, while the extractable, n-alkanes derive mainly from lower levels of the food chain. In the Messel Shale, isotopic compositions of individual biomarkers range from -20.9 to -73.4% vs PDB. Isotopic compositions of specific compounds can be interpreted in terms of origin from methylotrophic, chemautotrophic, and chemolithotrophic microorganisms as well as from primary producers that lived in the water column and sediments of this ancient lake.

Alkanes↗
PubMed1990

Surgical treatment of renal artery stenosis after failed percutaneous transluminal angioplasty.

From 1980 to 1989, 53 patients with renovascular hypertension underwent surgical treatment after initial unsuccessful management with percutaneous transluminal angioplasty. Renal artery stenosis was due to fibrous dysplasia in 17 patients and atherosclerosis in 36. The reasons for failure of percutaneous transluminal angioplasty were inability to dilate the stenotic lesion (32 patients), acute renal arterial occlusion (2) or dissection (8) from attempted percutaneous transluminal angioplasty, and the development of recurrent renal artery stenosis after initially successful percutaneous transluminal angioplasty (11). Three patients underwent nephrectomy due to the finding of a nonviable kidney at operation. Successful surgical revascularization was achieved in 50 patients. There was no significant fibrosis or inflammation around the previously dilated renal artery. Percutaneous transluminal angioplasty necessitated performance of a more complicated revascularization operation in only 1 patient. If the kidney is viable at operation in patients treated by percutaneous transluminal angioplasty renovascular reconstruction is not more technically difficult than when done primarily and the same excellent results can be achieved.

Angioplasty, Balloon↗
PubMed1990

Carbon-isotopic analysis of dissolved acetate.

Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of CO2 for mass-spectrometric analysis. For analysis of methyl carbon, acetic acid can be cryogenically trapped from the chromatographic effluent, then transferred to a tube containing excess NaOH. The tube is evacuated, sealed, and heated to 500 degrees C to produce methane by pyrolysis of sodium acetate. Subsequent combustion of the methane allows determination of the 13C content at the methyl position in the parent acetate. With typical blanks, the standard deviation of single analyses is less than 0.4% for acetate samples larger than 5 micromoles. A full treatment of uncertainties is outlined.

Acetates↗
PubMed1990

Origin of petroporphyrins. 2. Evidence from stable carbon isotopes.

Compared with the carbon-13 isotopic composition of the ubiquitous C32DPEP (DPEP, deoxophylloerythroetioporphyrin) the heavy but equivalent carbon-13 isotopic composition for the porphyrin structures 15(2)-methyl-15,17-ethano-17-nor-H-C30DPEP and 15,17-butano-, 13,15-ethano-13(2),17-propano-, and 13(1)-methyl-13,15-ethano-13(2),17-propanoporphyrin suggests a common precursor, presumably chlorophyll c, for these petroporphyrins isolated from the marine Julia Creek oil shale and the lacustrine Condor oil shale. Similarly, the heavy but variable carbon-13 isotopic composition of 7-nor-H-C31DPEP compared with C32DPEP is consistent with an origin from both chlorophyll b and chlorophyll c3. The equivalent carbon-13 isotopic composition for 13(2)-methyl-C33DPEP compared with C32DPEP suggests a common origin resulting from a weighted average of chlorophyll inputs.

Australia↗
PubMed1989

Incorporation and disappearance of oxygen-18 in lung from mice exposed to 1 ppm 18O3.

In this study, 18O3 was used as a tracer for inhaled ozone in mice. The amount of ozone-derived oxygen (ODO) in the lungs was determined by measuring the amount of oxygen-18 in excess of the natural abundance level which remained covalently bound to organic constituents of lung following exposure to 1 ppm 18O3 for less than or equal to 60 min. The rate of disappearance of ODO from the lungs was determined by quantifying the rate of decrease of oxygen-18 in excess of the natural abundance level in lung from mice exposed to 1 ppm 18O3 for 45 min. With exposure to 1 ppm 18O3. ODO accumulated in lung at a rate of 4.38 pmol/mg dry weight/min. Ozone-derived oxygen had a half-life in lung of approximately 6 hr. We estimate that a minimum of 44 pmol of O3 reacted with lung every minute of exposure to 1 ppm O3.

Animals↗