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Biomedical subjects

J Cohen

Publications and source records attributed to J Cohen.

At least 1,099 records · Page 61Linked to original sources
PubMed1989

In-vitro development and implantation of human embryos following culture on fetal bovine uterine fibroblast cells.

Human zygotes resulting from IVF were placed in two different culture systems to evaluate in-vitro development and to establish pregnancies in patients following embryo replacement. Treatment A (control) consisted of culturing zygotes in a modified Earle's Balanced Salt solution while treatment B consisted of culturing zygotes on a monolayer of fetal bovine uterine fibroblasts in this same culture medium. At the time of embryo replacement, embryos within treatments A and B had 3.7 and 4.3 blastomeres present, respectively. After 24 h in culture, the cellular fragmentation rate for treatment A embryos was 0.85 which was greater (P less than 0.05) than the fragmentation rate of 0.40 for embryos within treatment B. The incidence of implantation for patients whose embryos were given treatment A was 17.0% which was lower (P less than 0.05) than 35% for those given treatment B. Implantation rates increased with time in culture (43%) for treatment B embryos. Culture by treatment B of three-pronucleate zygotes resulted in 7/9 and 4/9 reaching the blastocyst and expanded blastocyst stages, respectively, whereas only 1/26 three-pronucleate zygotes cultured using treatment A reached either of these stages.

Blastocyst↗
PubMed1989

Hospital costs, use of resources, and dynamics of death associated with diabetes mellitus.

The federal Medicare DRG (diagnosis-related group) system is entering its sixth year. The hospital industry contends that DRGs are under-reimbursing for the hospital care provided. Our analysis by outcome (ie, survival vs death) of 3,329 patients with insulin-dependent or non-insulin-dependent diabetes mellitus showed that the 242 diabetes-related deaths were associated with a much more intense use of hospital resources and a substantial financial risk under DRG pricing schemes, compared with the 3,087 diabetic survivors. Only deaths within one week of admission to the hospital were profitable under DRGs. Patients who died after a hospital stay of more than 60 days generated a loss of $28,377 per patient. Diabetic patients who died after emergency admission tended to have a shorter hospitalization and to pose less financial risk under DRGs than those who died after nonemergency admission. Those who died after referral from other clinical services tended to have greater use of resources and to pose greater financial risk under DRGs than those not referred. These data suggest significant inequities in the current Medicare DRG prospective payment system vis-à-vis deaths from diabetes. Long hospitalization, nonemergency admission, and referral from another clinical service were shown to be good predictors of greater use of hospital resources for diabetic patients who died. However, since hospitals are not compensated for the increased utilization, diabetic patients may suffer a decline in quality of and/or access to medical care in the future.

Adolescent↗
PubMed1989

Rotavirus gene structure and function.

Knowledge of the structure and function of the genes and proteins of the rotaviruses has expanded rapidly. Information obtained in the last 5 years has revealed unexpected and unique molecular properties of rotavirus proteins of general interest to virologists, biochemists, and cell biologists. Rotaviruses share some features of replication with reoviruses, yet antigenic and molecular properties of the outer capsid proteins, VP4 (a protein whose cleavage is required for infectivity, possibly by mediating fusion with the cell membrane) and VP7 (a glycoprotein), show more similarities with those of other viruses such as the orthomyxoviruses, paramyxoviruses, and alphaviruses. Rotavirus morphogenesis is a unique process, during which immature subviral particles bud through the membrane of the endoplasmic reticulum (ER). During this process, transiently enveloped particles form, the outer capsid proteins are assembled onto particles, and mature particles accumulate in the lumen of the ER. Two ER-specific viral glycoproteins are involved in virus maturation, and these glycoproteins have been shown to be useful models for studying protein targeting and retention in the ER and for studying mechanisms of virus budding. New ideas and approaches to understanding how each gene functions to replicate and assemble the segmented viral genome have emerged from knowledge of the primary structure of rotavirus genes and their proteins and from knowledge of the properties of domains on individual proteins. Localization of type-specific and cross-reactive neutralizing epitopes on the outer capsid proteins is becoming increasingly useful in dissecting the protective immune response, including evaluation of vaccine trials, with the practical possibility of enhancing the production of new, more effective vaccines. Finally, future analyses with recently characterized immunologic and gene probes and new animal models can be expected to provide a basic understanding of what regulates the primary interactions of these viruses with the gastrointestinal tract and the subsequent responses of infected hosts.

Amino Acid Sequence↗
PubMed1989

Prostaglandin fevers in rats: regulated change in body temperature or change in regulated body temperature?

Experiments examining the effects of central injections of E-series prostaglandins (PGE) on body temperature have only been done in the light part of a light-dark cycle. The present experiments examined the characteristics of fevers in rats after intraventricular PGE2 injections in both light and dark in a 12:12 h photoperiod. In the light, the change in body temperature (Tb) after 0.5 microgram was not significantly different from the change after vehicle injection. After injection of PGE2 (1, 2, 4, and 8 micrograms), Tb rose in a dose-dependent fashion. Mean initial Tb in the light was 36.4-36.6 degrees C. Tb rose a mean of 1.5 degrees C after 1 microgram, 1.9 degrees C after 2 micrograms, 2.7 degrees C after 4 micrograms, and 3.5 degrees C after 8 micrograms PGE2. A dose of 16 micrograms gave almost identical results as 8 micrograms. In the dark, mean initial Tb was 37.4-37.7 degrees C. Tb rose less than 0.8, 1.1, 1.4, and 2.3 degrees C after 1-8 micrograms PGE2, respectively. Thus there were two distinct dose-response curves for day and night. Nevertheless, peak Tb values attained in the two conditions were not significantly different from each other at any given dose. These results show that a particular dose of PGE2 raises Tb to a particular level, largely independent of either the Tb at the time of the injection or the phase of the light-dark cycle. However, the change in Tb at any dose depends strongly on initial Tb. Therefore, we urge researchers in the pharmacology of thermoregulation to report initial and final Tb values as well as changes in Tb.

Animals↗
PubMed1989

Developmental loss of functional laminin receptors on retinal ganglion cells is regulated by their target tissue, the optic tectum.

The ability of chick retinal ganglion cells (RGCs) to extend neurites on tissue culture substrata of the extra-cellular matrix protein laminin is lost during embryonic development. In order to establish the mechanism responsible for the loss of response, the number of high affinity (KD 10(-9) M) laminin receptors on both the cell bodies and neurites of RGCs were determined throughout this period by a ligand binding assay using radio-labelled laminin. It was found that the loss of response paralleled a decrease in receptor numbers on both the cell bodies and the neurites of the RGCs. Bilateral tectal ablation at embryonic day 6 resulted in the subsequent maintenance of laminin-stimulated neurite outgrowth, together with a partial inhibition of the loss of laminin receptors. Thus, the loss of response of the RGCs to laminin reflects a decrease in the numbers of laminin receptors on these neurons, and furthermore, this down-regulation is in turn dependent on innervation of the target tissue.

Animals↗
PubMed1989

Alzheimer's disease: longitudinal CT studies of ventricular change.

A 3-year longitudinal study was conducted with 50 Alzheimer's disease patients and 45 elderly control subjects. All study participants received an extensive evaluation that included brain CT at baseline and follow-up. Quantitation of ventricular size, using both linear and volume methods, revealed highly significant cross-sectional and longitudinal differences between the Alzheimer patients and control subjects. Specifically, the annual rate of change in ventricular volume was approximately 9% in the Alzheimer patients and approximately 2% in the controls. The presence of age-related white matter lesions had no effect on the clinical course of the patients or on the changes in ventricular size. Among the Alzheimer patients, the rate of clinical decline was strongly related to the rate of change in ventricular size. Baseline ventricular measurements were of no value in predicting the subsequent rate of clinical deterioration or ventricular enlargement. The results suggest that changes in ventricular size closely reflect the clinical changes in Alzheimer patients.

Aged↗
PubMed1989

Antinuclear antibodies detected by indirect immunofluorescence on HEp2 cells and by immunoblotting in patients with systemic sclerosis.

The HEp2 cell cultures appeared highly sensitive in detecting the antinuclear antibodies (ANAb) in systemic sclerosis, principally anticentromere antibodies of the CREST syndrome. The immunoblotting used with either complex cellular extracts from HeLa and rabbit thymus or purified nuclear components (high mobility group (HMG) proteins and histones) is able to identify precisely the ANAb targets and to contribute to diagnosis. With nuclear extracts of HeLa cells, the sera from 75.8% of CREST syndrome subjects stained 18 and 22 kD proteins. Corresponding antibodies were also detected in 72.7% of these patients, on HEp2 centromers by indirect immunofluorescence. With the same extracts, 33.3% of sera from diffuse sclerosis/acrosclerosis patients contain antibodies staining 86, 73, 32 and 30kD. These sera also stain 77, 66 and 63kD from thymus extracts. Corresponding antibodies will be the anti-SCL-70 antibodies defined by double immunodiffusion. The anti-HMG antibodies were infrequent in systemic sclerosis, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and consequently without interest for diagnosis. The anti-whole histones antibodies which are less frequent in diffuse sclerosis/acrosclerosis (35.7%) than in SLE (41.3%) recognize especially H1 and H2A in the first diseases, H1 and H2B in SLE and H1 and H3 in RA.

Adult↗
PubMed1989

Hospital costs, resource characteristics, and the dynamics of death for hospitalized patients in cardiology Diagnosis-Related Groups.

A number of complex health policy questions face the nation regarding the Diagnosis-Related Group (DRG) prospective hospital payment system. An ongoing debate ensues at the federal level of the utility of improving the DRG system, given the "budget neutrality" provision of the DRG law. We analyzed hospital resource consumption for 5809 cardiology inpatients by outcome (i.e., survival vs death). Hospital resource use was greater and financial risk under DRG pricing schemes was substantial for the 312 deaths compared with the 5497 survivors. Only cases in which the patient died within 1 week of admission to the hospital were profitable under DRGs. A long hospital length of stay for patients who eventually died was very unprofitable (those who died after more than a 60-day hospital length of stay generated a $24,688 loss per patient). Patients who died after emergency admission tended to have a similar hospital length of stay and to be similar financial risk under DRGs, compared with nonemergency patients who died. Those patients who had been referred from other clinical services and who died caused greater resource use and financial risk under DRGs, compared with patients who were not referred and who died. These data suggest significant inequities in the current DRG prospective payment system for patients in cardiology DRGs who die. Variables predictive of greater hospital resource use for cardiology patients who die include longer hospital lengths of stay and referral from another clinical service. Health policy leaders should attempt to improve the equity of cardiology DRGs regarding outcome in the future.

Aged↗
PubMed1989

Studies on the specificity of the L929 cell bioassay for the measurement of tumour necrosis factor.

We report a study of the specificity of the L929 cell cytotoxicity assay for tumour necrosis factor (TNF) in clinical samples. Normal human serum caused marked killing and detachment of L929 cells. Despite heating at 56 degrees C for 30 min, followed by dilution, normal human serum still retained significant activity that could not be neutralized by a monoclonal antibody to TNF. In part this latter cytotoxicity was spurious, and related to detachment and clumping of viable cells. Recombinant human interleukin 1-beta (rhIL1-beta) and interferon-gamma (rhIFN-gamma) were not cytocidal, and did not synergize with recombinant human TNF (rhTNF) in the L929 cell bioassay. Although an antibody to TNF may be used to confirm specific activity, it is important to be aware of the limitations imposed by non-specific activity in serum and of the potential for synergy between TNF and other cytokines.

Animals↗
PubMed1989

Glass ionomers and discoloration: a comparative study of the effects of tea and coffee on three brands of glass ionomer dental cement.

This study was undertaken to compare the in vitro discoloration of 3 brands of glass ionomer dental cement, Chemfil, Fuji Type II, and Ketac-Fil. Forty-eight specimens of each brand were prepared. Sixteen specimens of each brand were placed in tea, coffee and, as a control, water. Discoloration was evaluated by means of reflection spectrophotometry at 2, 4, 8, and 16 wk. Analysis of the data indicated that most discoloration occurred during the first 2 wk of immersion in the staining media and a little further discoloration took place between 2 and 16 wk (p less than 0.05). Tea discoloured glass ionomer more than did coffee (p less than 0.05) and Fuji Type II discoloured the most, Ketac-Fil the least whilst the discoloration of Chemfil lay between these two (p less than 0.05).

Coffee↗
PubMed1988

Hospital costs, resource characteristics, and the dynamics of death for patients with hypertension.

A great deal of interest has begun to focus on outcome data for hospitals. We analyzed hospital resource consumption for 4289 patients with hypertension by outcome (ie, survivors vs mortalities). The 211 mortalities had a much greater intensity of hospital resource utilization and a substantial financial risk under diagnosis related group (DRG) pricing schemes compared with the 4078 survivors. Only mortalities within one week of admission to the hospital were profitable under DRGs. A long hospital length of stay (LOS) for mortalities was very unprofitable (mortalities with greater than 60-day LOS generated a $40,673 loss per patient). Patients admitted under emergency conditions who died tended to have a shorter hospital LOS and less financial risk under DRGs compared with those who were not emergency admissions and died. Mortalities referred from other clinical services tended to have greater resource utilization and financial risk under DRGs compared with nonreferred mortalities. These data suggest notable inequities in the DRG prospective payment system vis-à-vis patients who died with hypertension. They also demonstrated variables predictive of greater hospital resource utilization for patients who died with hypertension, including longer hospital LOS, nonemergency admission, and referral from another clinical service.

Aged↗
PubMed1988

Duration of storage of cryopreserved human embryos.

The incidence of cell injury, embryo survival, and implantation following cryopreservation of zygotes and two- to five-cell embryos was studied in 100 patients in order to evaluate the effect of duration of storage. The incidence of individual cell survival was 58% regardless of the length of time kept in liquid nitrogen or the stage of the embryo at freezing. There were 104 of 208 (50%) thawed embryos that survived completely intact, and of those, 24 implanted successfully. Twenty-one (21%) patients had a clinical pregnancy; two of them miscarried Neither the survival of zygotes or cleaved embryos upon thawing nor the incidence of implantation was affected by the duration of cryostorage.

Cleavage Stage, Ovum↗