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Biomedical subjects

S Weinstein

Publications and source records attributed to S Weinstein.

At least 73 records · Page 4Linked to original sources

Reducing pathology test misuse.

Our laboratory serves a 450-bed acute care hospital in the rapidly growing Gold Coast region. The problem facing the department comprised an almost 10 per cent yearly increase in patient numbers in the face of budgetary constraints and pressure to increase efficiency. In January and February 1992 a vigorous effort was made to reduce pathology test numbers without compromising quality of patient care. The approach adopted involved targeting 'unnecessary' tests, defined as those investigations that would not affect a clinician's management of the patient. A team effort by laboratory scientific staff and heads of clinical departments was aimed at scrutinizing the ordering patterns of junior medical staff, who generate most of the test requests. The result was a 'test per patient' figure of 8.2 for both months, calculated as the number of tests on each request form received. In comparison, for January and February of the preceding four years, 1988 to 1991, the number of tests per patient fluctuated between 9.9 and 11.8. Patterns of unnecessary ordering that emerged included duplicate ordering of identical tests due to poor communication between house-staff, too frequent repeats of tests (for example, daily liver function tests), crossmatch where low transfusion likelihood would make group-and-hold appropriate, tests generated by nursing staff, and numerous others where the result would not affect management (or indeed even be looked at!). The nearly 20 per cent drop in tests does not include those instances where all tests on a request form were disallowed and the encounter therefore not included as a 'patient' statistic.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Laboratory Techniques↗

Age-related changes in hyaluronan, proteoglycan, collagen, and osteonectin synthesis by human bone cells.

Human bone cells grown in culture, representative of a preosteoblastic stage of maturation, produce an extracellular matrix composed of collagen, several noncollagenous glycoproteins, hyaluronan, and four distinct proteoglycans (PGs). The influence of donor age on the levels of expression of these molecules in vitro has not been well characterized. In this study, human bone cells derived from sources ranging from fetal to 60-year-old donors were grown in culture, radiolabeled for 24 h, and the amount of incorporation of [35S]sulfate into PGs, [3H]glucosamine into hyaluronan, [3H]leucine/proline into osteonectin, and [3H]proline into collagen was determined. Cell proliferation was most rapid in fetal-derived bone cells and decreased with increasing age. Total protein and PG synthesis also decreased with increasing age, falling to 1/3 and 1/4, respectively, of fetal levels after age 30. A large chondroitin sulfate PG (Mr approximately 600,000 Da) was the major fetal PG and its levels were highly correlated with cellular proliferation. [3H]Collagen and [35S]decorin levels increased with the increasing age of the donor, reached a maximum in puberty-derived cells, and decreased to 1/3 maximal levels after age 20. The heparan sulfate PG (Mr approximately 400,000 Da) exhibited steady-state levels regardless of donor age. [3H]Osteonectin and [35S]biglycan levels were high in fetal-derived cells and in cells derived from pubescent donors. The percentage of collagen and four proteoglycans associated with the cell layer pool changed with donor age. All fetal-derived PG core proteins possessed more N- and O-linked oligosaccharides than newborn or adult derived PGs.

Aging↗

Crystals of complexes mimicking protein biosynthesis are suitable for crystallographic studies.

A complex of 70S ribosomes from Thermus thermophilus together with an average of 1.5-1.8 equivalents of PhetRNA(Phe) and a short mRNA chain, composed of 35 +/- 5 uridines, was crystallized under the conditions used for the growth of crystals of isolated ribosomes from the same source. Considering the reproducibility of their growth, their internal order and their shape, the crystals of the complex are superior to those of isolated ribosomes. In accord with previous three-dimensional reconstruction and modeling experiments, we conclude that the complex is less flexible and that an average population of complexes is more homogeneous than that of isolated 70S ribosomes. The crystals of the complex diffract to higher than 15 A resolution and can be irradiated with synchrotron X-ray beam at cryo-temperatures for days without noticeable decay. Since the crystals of the complex are apparently isomorphous with these of the isolated 70S ribosomes (P4(1)2(1)2; a = b = 526; c = 315 A), they should provide tool for phasing as well as for locating the mRNA and tRNA binding sites.

Computer Graphics↗

Late results of combined iodine-125 and external beam radiotherapy in carcinoma of prostate.

A total of 96 patients were treated for localized carcinoma of the prostate using combined Iodine-125 (125I) implantation and external beam radiotherapy. The implant was tailored to deliver 10,000 rad to the periphery of the prostate. A significant incidence of serious late rectal complications was observed. Positive pelvic nodes were found in 28 percent of the patients. Disease-free survival at seven years was 76 percent for those with negative nodes and 46 percent for patients with positive nodes.

Fistula↗

Apoplectic headache and oculomotor nerve palsy: an unusual presentation of multiple sclerosis.

A patient with a history of facial myokymia presented with apoplectic headache and a 3rd nerve palsy. Initial CT, lumbar puncture, and cerebral angiogram were unremarkable, but subsequent CSF examination revealed oligoclonal bands. MRI displayed over 30 white matter lesions. This case demonstrates that multiple sclerosis may present with severe headache and a 3rd nerve palsy, simulating the clinical picture of a posterior communicating artery aneurysm.

Adult↗

Orotactile sensation, gustation and palatability: a pilot study.

The hypothesis that deficits in orotactile sensitivity may affect gustation and palatability is not new. It is supported by animal models employing deafferentation; however, little direct evidence supports the application of the model to humans. Indirect evidence comes from four separate fields: (1) neuroanatomy, (2) physiology, (3) developmental biology, and (4) learning theory. The results of a pilot study with humans provide additional direct evidence that implicates the role of orotactile sensitivity in human gustation. In this pilot study, the oral cavity was topically anesthetized to determine whether gustation would be compromised to a similar extent as orotactile sensitivity. The time course of the degree of anesthesia was determined by prior measurements of oral-tactile sensitivity using an oral air-based aesthesiometer. Different concentrations of NaCl-solution were presented to subjects in order to determine gustatory thresholds before and after anesthesia. Analysis of magnitude-estimation data indicated that there were statistically significant decreases in gustatory sensitivity after anesthesia. Basic and applied implications of this area of research are discussed.

Adult↗

Uses of orthoclone OKT3 for prophylaxis of rejection and induction in initial nonfunction in kidney transplantation.

We have shown that OKT3 can be safely administered to a varied group of transplant recipients, including a high percentage of diabetics and older patients. Used as a prophylactic agent, OKT3 was associated with a decreased incidence and delayed onset of acute rejection. Effectiveness may be reduced by shortening the course of treatment and/or lowering the dose of concomitant azathioprine. Use of OKT3 in patients with ATN (thereby avoiding use of CyA) may be a beneficial strategy. Stimulation of significant titers of antimurine antibody has not been a common event in this study.

Adolescent↗

Novel procedures for derivatization of ribosomes for crystallographic studies.

Undecagold and tetrairidium clusters have been used for the preparation of heavy-metal derivatives of ribosomal particles, necessary for the evaluation of phases in the x-ray structure determination of these large particles. To obtain specific binding, monofunctional reagents of the clusters were prepared and were covalently bound to free sulfhydryl groups on the surface of the ribosome. In addition, a mutant of Bacillus stearothermophilus which lacks one ribosomal protein (BL11) was grown. The heavy-atom clusters were covalently bound to isolated protein BL11, and the modified protein was consequently reconstituted into the mutated ribosomal subunits. Crystallographic data have been collected from crystals of native particles, from the mutated ones, and from the iridium- and gold-derivatized subunits. All these crystal forms are isomorphous within the experimental error.

Crystallization↗

Routine excretory urography in follow-up of superficial transitional cell carcinoma of bladder.

To determine cost-effective guidelines for the follow-up of patients with superficial transitional cell carcinoma of the bladder (STCCAB), we reviewed clinical histories, pathology reports, and intravenous pyelography results in 84 patients with Stage Ta or T1 disease. In 4 patients (4.8%) subsequent upper tract tumors developed with an average interval from initial presentation to the development of upper tract disease of 5.4 years. Three of these patients were treated successfully. We recommend upper tract surveillance in this group of patients with intravenous pyelography at diagnosis and every twenty-four months thereafter, or selection of those patients who are at high risk for development of upper tract disease (i.e., ureteral-vesical reflux) with voiding cystourethrography one month following each resection of tumors near a ureteral orifice. Refluxing patients should then either undergo surgical repair of their reflux or yearly pyelography.

Carcinoma, Transitional Cell↗

Ocular infections and the industrial use of microscopes.

A cluster of ocular infections occurred in one area of a computer fabrication facility that relied on the use of industrial microscopes. A questionnaire was administered to all employees in this area. Microscope oculars were cultured and compared with control microscopes from a nonindustrial setting. Risk of infection was correlated with the number of hours of microscope use per day and subjective indicators of cleanliness. Bacterial cultures confirmed increased colony counts in industrial oculars compared with control oculars. Hygienic practices were instituted similar to those employed in medical settings. No further outbreaks of conjunctivitis have been reported in a 1-year follow-up.

Conjunctivitis↗

OKT3 prophylaxis versus conventional drug therapy: single-center perspective, part of a multicenter trial.

As part of a collaborative study, Orthoclone OKT3 (Ortho Pharmaceutical Corporation, Raritan, NJ) monoclonal anti-T-cell antibody was used prophylactically for 14 days following cadaveric renal transplantation. Patients were randomized before treatment and compared with a control group treated with triple-drug immunosuppressant therapy consisting of cyclosporine, azathioprine, and prednisone. The OKT3 group (also treated with prednisone and azathioprine) had significantly fewer patients with acute rejection during the first year (27% v 60%), significantly delayed onset of acute rejection (median number of days to rejection, 56 v 10), and shortened duration of delayed initial graft function (median number of days on nonfunction, 5.5 v 9.0). OKT3 was safely administered intraoperatively. The study group included diabetics and patients over the age of 50 years. There was an increased incidence of benign fungal infection in patients treated with OKT3. The outcome data of both the prophylactic and control groups in this single-center trial was different from the multicenter experience in that patient and graft survival was 100% in both groups. The only difference in the immunosuppressive protocol was the use of 2 g intravenous methylprednisolone intraoperatively. The combination of intraoperative OKT3 with 2 g methylprednisolone may merit further study. It was concluded that OKT3 prophylaxis reduces the incidence of rejection episodes, delays the occurrence of rejection, and may reduce the duration of delayed initial graft function. It is not associated with an increase in serious infection and can be administered safely to a variety of cadaver transplant recipients.

Antibodies, Monoclonal↗

Senior adult sexuality in age segregated and age integrated communities.

Middle-income older adults who select to reside in age-segregated (AS) leisure-type retirement communities exhibit significantly more sexual interest, sexual activities, and liberal sexual attitudes than do middle-income older adults residing in age-integrated (AI) mainstream communities. Data from 314 respondents on a senior adult sexuality scale were subjected to a discriminant analysis. Sexual activities and traditional sexual interests respectively make the strongest contribution to the group differences. The implications of these findings are discussed.

Aged↗

Four-year experience with exclusive use of cytomegalovirus antibody (CMV-Ab)-negative donors for CMV-Ab-negative kidney recipients.

Because of unacceptable CMV related morbidity, mortality, and graft loss, we adopted a policy that (-) patients would receive renal allografts only from (-) donors. This policy has resulted in a significant decrease in (1) morbidity (10.6% v 1.7%, P less than .0001), (2) mortality (3.7%) v 0%, P = .002), and (3) graft loss (2.5% v 0%, P = .016). CMV-Ab-negative patients (1) constitute 26% of all patients tested (compared with 36% of all donors tested), (2) receive transplants at the same rate as (+) patients, (3) do not have a prolonged waiting time, and (4) received greater HLA-A, B, -DR mismatched kidneys (3.6 v 3.1, P less than .01).

Antibodies, Viral↗

Three-dimensional image reconstruction from ordered arrays of 70S ribosomes.

A better understanding of the molecular mechanism of protein biosynthesis still awaits a reliable model for the ribosomal particle. We describe here the application of a diffraction technique, namely three-dimensional image reconstruction from two-dimensional sheets of 70S ribosomes from Bacillus stearothermophilus at 47 A resolution. The three-dimensional model obtained by these studies shows clearly the two subunits, the contact points between them, an empty space large enough to accommodate the components of protein biosynthesis, the location of regions rich in RNA and a possible binding site for mRNA. The tunnel within the 50S particle which may provide the path taken by the nascent polypeptide chain in partially resolved.

Geobacillus stearothermophilus↗