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Biomedical subjects

S Weiner

Publications and source records attributed to S Weiner.

At least 181 records · Page 10Linked to original sources
PubMed1985

Organic matrixlike macromolecules associated with the mineral phase of sea urchin skeletal plates and teeth.

The skeletal plates and teeth of the echinoid Paracentrotus lividus contain a heterogeneous assemblage of macromolecules that are not part of the connective tissue, but are presumably intimately associated with the mineral phase. Upon dissolution of the Mg-calcite mineral phase, some of these molecules are insoluble. The insoluble fractions of the teeth and skeletal plates are quite different, the former being predominantly protein and the latter, primarily some unknown nonproteinaceous material. The soluble constituents are similar in both tissues. These hydrophilic macromolecules have been partially separated and characterized. In both hard parts, two distinct classes of macromolecules are present, as indicated by the amino acid compositions of their protein constituents. These two classes of macromolecules are also present in the shells of a foraminifer and in various mollusks, both of which are formed by the "organic matrix-mediated" biomineralization process. The locations of these macromolecules in the teeth and skeletal plates are not known, nor whether they form coherent structures. It is therefore premature to conclude that these macromolecules do function as an organic matrix, although the results presented are in agreement with such an interpretation.

Amino Acids↗
PubMed1985

Phase I trial of carboplatin-cyclophosphamide and iproplatin-cyclophosphamide in advanced ovarian cancer: a Southwest Oncology Group study.

The Southwest Oncology Group has carried out a phase I clinical trial of carboplatin plus cyclophosphamide and iproplatin plus cyclophosphamide in 20 patients with stages III and IV ovarian cancer prior to initiating a phase III trial to compare these platinum analog-cyclophosphamide combinations with standard cisplatin-cyclophosphamide therapy. Myelosuppression proved the dose-limiting toxicity of both the carboplatin (300 mg/m2) plus cyclophosphamide (600 mg/m2) and iproplatin (180 mg/m2) plus cyclophosphamide (600 mg/m2) regimens. Evaluating up to six courses of therapy (repeated at 4-week intervals), the median nadir WBC and platelet counts associated with carboplatin-cyclophosphamide therapy were 1800 (range, 900-4000) and 69 000 per microliter, respectively, and those associated with iproplatin-cyclophosphamide therapy were 1400 (1100-1600) and 140 000 per microliter, respectively. Although the starting doses of carboplatin and iproplatin required a median decrease of 25%, the median doses of each administered through six courses of therapy were 300 and 180 mg/m2, respectively. Neither nephrotoxicity nor neuropathy were experienced by the patients, but mild to moderate nausea and vomiting occurred in more than 75% of those treated with either drug combination. Alopecia of mild to severe degree was observed in 40% of patients. Although the results of this phase I trial are still preliminary, we can recommend for future phase III trials 300 mg/m2 carboplatin and 180 mg/m2 iproplatin when combined with 600 mg/m2 cyclophosphamide repeated a 4-week intervals for six treatment courses.

Adult↗
PubMed1985

Interactions between acidic proteins and crystals: stereochemical requirements in biomineralization.

Acidic matrix macromolecules are intimately involved in biological crystal growth. In vitro experiments, in which crystals of calcium dicarboxylate salts were grown in the presence of aspartic acid-rich proteins, revealed a stereochemical property common to all the interacting faces. Calcite crystals are nucleated on stereochemically analogous faces when proteins are adsorbed onto a rigid substrate. The importance of this property in biomineralization is discussed.

Animals↗
PubMed1985

Inpatient clinical trial of lorazepam for the management of manic agitation.

Antipsychotic medications have traditionally been used for their sedative effects in the management of the behavioral and emotional agitation of mania while awaiting the therapeutic effect of lithium. On the premise that a nonantipsychotic sedative might satisfactorily and more specifically control this agitation without neuroleptic or hypotensive side effects and without prolongation of the acute illness, the authors conducted an open trial with four acutely manic patients in which only the benzodiazepine lorazepam was administered along with lithium; no antipsychotic medications were used. Lorazepam, administered in oral and parenteral form on an as-needed basis to maintain patient cooperation with the treatment plan and milieu, was found to be rapid and effective in controlling the manic agitation of these patients, with few troublesome side effects, and with no obvious prolongation of the acute illness.

Adult↗
PubMed1985

Investigative auditing.

The use of traditional audit approaches, such as those employed by the accounting profession, frequently fail to uncover losses or the causes of such losses in an operation such as hospital linen. In this article, the authors describe a different type of audit, called Investigative Auditing, and relate how it was used at one institution to uncover a serious theft problem and recommend better techniques.

Bedding and Linens↗
PubMed1985

Contraction stress testing with nipple stimulation.

The contraction stress test (CST) is used widely as a measure of fetoplacental respiratory reserve. With contractions traditionally induced by intravenous oxytocin, the test has been limited in its use by time, expense and patient discomfort. In a prospective evaluation of the effectiveness of nipple stimulation for the production of uterine contractions, a successful CST was obtained in 94% of the attempts, with a mean total test time of 12 minutes.

Adolescent↗
PubMed1984

A [14C]2-deoxyglucose analysis of the functional neural pathways of the limbic forebrain in the rat. IV. A pathway from the prefrontal cortical-medial thalamic system to the hypothalamus.

The present study utilized the [14C]2-deoxyglucose (2-DG) cell labeling procedure to characterize a functional pathway from the prefrontal cortex (Pfc) and mediodorsal thalamic nucleus (MD) to the hypothalamus. Rats were injected with 2-DG prior to a 45 min experimental paradigm consisting of alternating 30 s on-off periods of electrical brain stimulation. Standard procedures were utilized for the removal and processing of brain tissue for X-ray autoradiography. In the first phase of this study, stimulation applied to the prefrontal cortex generally yielded a pattern of 2-DG distribution consistent with the findings of classical anatomical studies. Stimulation of the dorsomedial and ventromedial prefrontal cortex or the infralimbic cortex produced the most effective activation of the diencephalon. This activation was primarily limited to MD, with no involvement of any region of the hypothalamus. In the second phase of this study, brain regions activated following stimulation of sites along the rostro-caudal axis of MD were examined. Stimulation of MD resulted in the activation of the nucleus reuniens and other midline and non-specific thalamic nuclei. Stimulation of this nucleus also activated the ventromedial thalamic nucleus, medial aspects of the nucleus accumbens and the medial and sulcal prefrontal cortices. Again, in each of these cases, labeling within any region of the hypothalamus could not be detected. Since MD stimulation activated the midline thalamus, and the nucleus reuniens in particular, the last phase of this experiment involved stimulation of the nucleus reuniens in order to determine the source of medial thalamic inputs to the hypothalamus. Stimulation of the nucleus reuniens activated fibers which were distributed to both the medial and lateral hypothalamus. In addition, stimulation also activated the descending periventricular system, which could be followed to the level of the midbrain central gray and such limbic structures as the hippocampal formation, septal area, amygdala and prefrontal cortex. These findings indicate that Pfc-MD activation of the hypothalamus is achieved indirectly via interneurons within the nucleus reuniens.

Animals↗
PubMed1984

Retroperitoneal malacoplakia.

Malacoplakia is an uncommon, pathologically distinct, granulomatous disease that occurs most frequently in the urinary tract. It can present as an abdominal mass in a patient with urinary tract infection. A case of retroperitoneal malacoplakia with CT findings and successful treatment with radiation therapy is presented.

Adolescent↗
PubMed1984

Enamel rod relations in the developing rat incisor.

Scanning electron microscopic and X-ray diffraction studies have shown that mandibular rat incisor teeth have two sets of rods which decussate at angles between 60 and 80% in both the most immature zone and the zone just beyond the opaque margin. A less well oriented interrod enamel component was found at right angles to both sets of rods. The information provides additional views of this complex tissue. Furthermore, it has been shown that the Wistar rat incisal enamel ultrastructure facilitates the use of X-ray diffraction to determine molecular relations between the crystals and matrix constituents as the rods are not all at 90 degrees to one another.

Ameloblasts↗
PubMed1984

A 30-year experience with bone graft epiphysiodesis in the treatment of slipped capital femoral epiphysis.

A retrospective review was carried out of all cases treated by bone graft epiphysiodesis for slipped capital femoral epiphysis at Children's Hospital Medical Center of Akron between the years 1950 and 1980. Only those cases followed for a minimum of 1 year following treatment were included in the review and evaluated as to their status of avascular necrosis, acute cartilage necrosis, or other complications attendant to the surgical approach. One hundred seventy-six patients representing 207 hips underwent bone graft epiphysiodesis over this 30-year period. One hundred fifty-nine patients representing 185 hips were followed a minimum of 1 year and were included in this study. There were 25 cases of acute slipping representing 26 hips and 134 patients representing 159 hips involved with the chronic slipping process. In the acute group of patients representing 26 hips, there were two cases of avascular necrosis and one case of acute cartilage necrosis. In the chronic group of 159 hips, there were four cases of reslipping, one due to graft resorption, one due to placement of the graft short the growth plate, and two that went on to acute slipping. All cases were salvaged with good results. There was one case of avascular necrosis in the chronic group; not a single case of acute cartilage necrosis was encountered. Owing to the rapid nature of growth plate closure following bone graft epiphysiodesis, the avoidance of hardware removal or pin penetration, and the extremely low incidence of overall complications, we suggest that bone graft epiphysiodesis is at least as good as multiple pin fixation in the treatment of slipped capital femoral epiphysis.

Adolescent↗
PubMed1983

Landmarks during the first forty-two days of gestation demonstrated by the beta-subunit of human chorionic gonadotropin and ultrasound.

Prospective pregnancy evaluation through the combined use of a radioimmunoassay (RIA) for the beta-subunit of human chorionic gonadotropin (beta-hCG) and ultrasound during the first 42 days of gestation after ovulation was performed on a population asymptomatic for first-trimester spontaneous abortion. One hundred forty-six ultrasonic observations in 98 pregnancies were made with simultaneous beta-hCG RIA performed in 80 patients. The following landmarks of normal gestational growth were identified: (1) Before 26 days, beta-HCG RIA permits definitive diagnosis of growing trophoblastic tissue, and serial samples allow doubling time computation for prognosis while ultrasound shows a nonspecific increasing decidual response within the uterus; (2) between 26 and 36 days after ovulation, serial beta-hCG samples continue to give doubling time results while ultrasonic demonstration of a gestational sac is normally seen by 28 days after ovulation; (3) the lack of fetal heart motion by 42 days after ovulation or within a gestational sac with a mean diameter of greater than 30 mm was prognostic of abortion; (4) the absence of a gestational sac by 28 days after ovulation or with a beta-hCG RIA greater than 1,000 ng/ml is suggestive of an ectopic pregnancy until proved otherwise.

Abortion, Threatened↗