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Biomedical subjects

S Stein

Publications and source records attributed to S Stein.

At least 91 records · Page 5Linked to original sources
PubMed1993

Evaluation of a new blood-conserving arterial line system for patients in intensive care units.

OBJECTIVE: To evaluate blood samples obtained from a new blood-conserving arterial line system for the presence of hemodilution or heparin contamination. DESIGN: Prospective, clinical trial. SETTING: A coronary intensive care unit in a tertiary-care teaching hospital. PATIENTS: Cardiovascular patients in whom invasive arterial blood pressure monitoring was indicated. INTERVENTIONS: Paired blood samples were obtained from a conventional arterial line system and a new blood-conserving arterial line system for the measurement of hematocrit and partial thromboplastin time, and compared to evaluate for the presence of either hemodilution or heparin contamination. MEASUREMENTS AND MAIN RESULTS: A Bland-Altman bias analysis of the variability between the two blood draw methods was performed. The analysis indicated that a) a randomly determined partial thromboplastin time obtained from the blood-conserving arterial line would lie between 3.32 and -5.11 of the partial thromboplastin time taken from the conventional arterial line value with 95% confidence; and b) a randomly determined hematocrit obtained from the blood-conserving arterial line would lie between 1.97 and -1.85 of the hematocrit taken from the conventional arterial line value with 95% confidence. CONCLUSIONS: We concluded that a) blood samples obtained with the blood-conserving arterial line demonstrate no evidence of hemodilution or heparin contamination; b) the blood-conserving arterial line provides blood samples without the need for an initial volume of blood to be discarded; c) the blood-conserving arterial line provides a means for blood conservation in the intensive care setting.

Blood Pressure Monitors↗
PubMed1993

Shifts in diagnostic frequencies of schizophrenia and major affective disorders at six North American psychiatric hospitals, 1972-1988.

OBJECTIVE: This study tested the impression that there have been significant shifts in the relative diagnostic frequencies of schizophrenia and major affective disorders. METHOD: Data on discharge diagnoses from 1972 to 1988 were gathered from six North American psychiatric teaching hospitals (data from one extended through 1991), and rates for schizophrenia and major mood disorders were evaluated. RESULTS: Total annual discharges increased by 6.6% during the study period. Large reciprocal shifts in the frequencies of diagnoses of schizophrenia and major affective disorders were found; schizoaffective disorder was a minor diagnosis. Beginning in the early 1970s, a gradual increase in the frequency of diagnoses of major affective disorders at all sites was accompanied by a corresponding decrease in diagnoses of schizophrenia at five of the six centers. Schizophrenia diagnoses decreased from a peak of 27% in 1976 to 9% in 1989 (a threefold decrease), and diagnoses of major affective disorders rose from a low of 10% in 1972 to 44% in 1990 (a fourfold increase). CONCLUSIONS: Several forces may have influenced these changes. 1) DSM-III narrowed the definition of schizophrenia and broadened the category of major affective disorders. 2) Treatment-oriented diagnostic bias associated with the availability of lithium and other mood-altering agents may have encouraged consideration of affective disorders. 3) Economic and social forces, including better third-party reimbursement rates, may have favored affective diagnoses. 4) True increases in the incidence of affective disorders may have occurred. 5) Although a real decrease in new cases of schizophrenia may have occurred, this effect was probably minor and dominated by a larger shift of such diagnoses to affective categories.

Canada↗
PubMed1992

The structural basis for the electrophoretic isoforms of normal and variant human platelet arylsulphatase A.

Human platelet arylsulphatase A (ASA) exhibits a multiple banding pattern when examined by PAGE. The isoform pattern (IVa) of the enzyme obtained from normal subjects differs from variants (IIIa, IIIb, IVb) which are primarily found in alcoholic patients. Alkaline phosphatase and endo-N-acetylglucosaminidase H treatments, as well as ion-exchange chromatography, demonstrate that the isoforms of ASA arise because of charge heterogeneity caused by phosphoglycan moieties. The isoform with the slowest mobility in PAGE lacks phosphate substituents. Based upon mannose-6-phosphate-receptor affinity chromatography it can be concluded that most, if not all, of the enzyme-linked phosphate is in the form of 6-O-phospho-D-mannosyl units. Lectin affinity chromatography and peptide-N-glycosidase F treatment followed by SDS/PAGE and Western-blot analysis indicate that normal platelet ASA contains two oligomannose and/or hybrid glycan moieties of which one, or both, possess a 6-O-L-fucosyl substituent on the asparagine-linked N-acetylglucosamine residue. Comparative analysis indicates that the variant IIIa and IIIb types of ASA differ from the IVa ASA with regard to the level of glycan phosphorylation and glycan structure, as well as the polypeptide structure.

Alcoholism↗
PubMed1992

Design of peptide-acridine mimics of ribonuclease activity.

A series of peptide-acridine conjugates was designed and synthesized, based on three features of the proposed catalytic mechanism of RNase A: 2'-proton abstraction by His-12, proton donation to the leaving 5'-oxygen by His-119, and stabilization of the pentacoordinated phosphorous transition state by Lys-41. The substrate binding capability of RNase A was mimicked by the intercalator, acridine. Lysine served as a linker between acridine and the catalytic tripeptide. Cleavage of target RNA was monitored by agarose gel electrophoresis and by gel-permeation chromatography. The carboxyl-amidated conjugates HGHK(Acr)-NH2, HPHK(Acr)-NH2, and GGHK(Acr)-NH2 (where Acr indicates 2-methyl-9-acridinemethylene) all had similar hydrolytic activity. The catalytic mechanism most likely involved only the abstraction of the 2'-proton and stabilization of the transition state. These RNase mimics utilized rRNA and single-stranded RNA but not double-stranded RNA and tRNA as substrates.

Acridines↗
PubMed1992

Abbreviated injury scaling of head injury as a prognostic tool for functional outcome.

The use of Abbreviated Injury Scaling for the head region (HAIS) was evaluated as a prognostic index of functional outcome in 503 consecutive patients with severe injury to the brain who survived initial resuscitation. Although a strong statistical relationship between HAIS and outcome as measured by the Glasgow Outcome Scale was demonstrated, its clinical usefulness is limited. HAIS may be most useful as a classifier for comparative studies of populations and for the evaluation of therapeutic modalities.

Abbreviated Injury Scale↗
PubMed1992

Specific G proteins mediate endothelin induced contraction.

Endothelin is a potent vasoconstrictor peptide which has recently been localized in the gastrointestinal tract. We have investigated the transmembrane signaling properties of endothelin in isolated smooth muscle cells of the rabbit rectosigmoid. Endothelin induced a dose dependent contraction of smooth muscle cells in a range of 10(-10) to 10(-6)M. In normal buffer, contraction peaked at 30 sec and was sustained for up to 8 min. Incubation in 0Ca/2mM EGTA abolished the sustained contraction induced by endothelin, but had no effect on the initial transient contraction. Preincubation of saponin treated cells with G protein antisera had no effect on control cell length. Preincubation of saponin treated isolated smooth muscle cells with specific G protein antisera (rabbit antisera) for Go alpha or Gs for 60 minutes did not inhibit contraction induced by endothelin. Preincubation with an antiserum to Gi3 alpha inhibited the initial transient contraction induced by endothelin and preincubation with an antiserum to Gi1-2 alpha inhibited the sustained phase of the endothelin induced contraction. Our data indicate that: 1) Endothelin induces a direct sustained contraction of smooth cells from the rectosigmoid; 2) The transmembrane signalling of endothelin is through two specific GTP binding components that are Gi alpha, one for the initial transient contraction, and the other for the sustained phase of the contraction.

Animals↗
PubMed1992

An evaluation of the esophageal detector device using a cadaver model.

The study was conducted to evaluate the usefulness of an esophageal detector device (EDD) to correctly differentiate between esophageal and tracheal intubation. The study was conducted in the emergency department using 10 recently decreased cadavers (nine males, one female, age range 50-72 years). An 8-mm internal diameter endotracheal tube was placed orally into the trachea, and a second 8-mm ID tube was placed orally into the esophagus. Both tubes extended the same distance from the mouth, and the cuffs were not inflated. After placement of the tubes, the EDD was used by advanced life support providers (physicians, nurses, paramedics, and respiratory therapists) to determine if each tube was in the trachea or the esophagus. The persons who assessed the tube placement were not present when the tubes were placed into the cadavers. Multiple evaluators were allowed for each cadaver, but each evaluator only participated one time for each cadaver. The bulb of the EDD was squeezed by the evaluator, who then attached it to the endotracheal tube and rated the bulb inflation as immediate inflation, delayed inflation, or no inflation. Prior to participation in the study, evaluators were instructed in the use of the EDD. There were a total of 45 trials performed on the cadavers (median, four evaluations/cadaver, range, one-eight). For the tracheal tube, the EDD inflated immediately in all cases; it was thus 100% correct in identification of tracheal intubation. For the esophageal tube, the EDD did not inflate in 44 cases, and in one case it filled with vomitus; it thus correctly identified esophageal intubation in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Internally standardized amino acid analysis for determining peptide/carrier protein coupling ratio.

A method based on amino acid analysis has been developed for monitoring the covalent conjugation of synthetic peptide haptens to carrier proteins. The marker amino acid, alpha-aminobutyric acid, is included in the sequence during peptide synthesis. Following reaction, the carrier protein-conjugate is freed of excess peptide by two successive rounds of gel filtration chromatography. Amino acid analysis of a hydrolysate of the conjugate allows the calculation of the coupling ratio of the peptide to the carrier protein. Two typical procedures for conjugation, carbodiimide cross-linking and cysteine-thiol reaction with maleimidyl-proteins, have been evaluated.

Amino Acid Sequence↗
PubMed1991

Desired control and felt control as mediators of stress in a dental setting.

Control-related variables have clearly affected stress responses in previous research (Thompson, 1981). Prior work, however, has primarily emphasized the amount of control that subjects perceive they have. In the three studies reported here, we examined the added predictive utility of assessing subjects' desire for control. Data from all three studies indicate that subjects who have a high desire for control coupled with a low feeling of control are characterized by particularly high degrees of dental distress. These results were found both in settings where patients anticipated immediate dental treatment and where treatment was not imminent. In addition, the results indicate that this "at risk" group reported greater distress before and immediately after actual dental treatment. Furthermore, they remembered their dental treatment as being more aversive 1 week after treatment. The practical implications and theoretical significance of these data are considered.

Adult↗
PubMed1991

The influence of theory on the psychoanalyst's countertransference.

The emotional reaction in the analyst occurs in shared analytic work under the influence of the patient's transference phantasies and is the analyst's creation and contribution. The idea that the analyst has emotions introduced directly into the analyst by the patient such that the analyst contains somebody else's feelings is refuted. Examples have been offered to show how the analyst's working theory influences the countertransference. If the analyst is unaware of this, the analyst may mistakenly attribute negative countertransference to the patient's projection.

Conflict, Psychological↗
PubMed1990

Clinical evaluation of flexor tendon function in the small finger.

Patients frequently present to the emergency department with hand injuries. Standard examination includes testing each digit for flexor function. The flexor digitorum superficialis (FDS) to the small finger has been shown to have variable anatomy and clinical examination. We prospectively examined 100 subjects (200 hands) for small finger FDS function by standard and modified testing. We found that 70 small flexors (35%) showed absent FDS by standard testing, whereas only eight fingers (4%) had absent FDS by modified testing. FDS function to the small finger is frequently unilateral. We conclude that modified testing is the only way to accurately test for small finger FDS function and that the use of this simple clinical examination may prevent unnecessary referral to a hand surgeon.

Adult↗
PubMed1990

Neurovirulence determinants of genetically engineered Theiler viruses.

Theiler murine encephalomyelitis viruses (TMEVs) are picornaviruses that cause enteric and neurological disease in mice. The GDVII strain and other members of the GDVII subgroup are highly virulent and cause an acute, fatal polioencephalomyelitis following intracerebral inoculation, whereas the DA stain and other members of the TO subgroup cause a persistent, demyelinating infection. We previously produced a full-length, infectious DA cDNA clone. We now describe the generation of a full-length, infectious GDVII cDNA clone and the subsequent production of intratypic chimeric cDNAs and intratypic recombinant viruses. Inoculation of the recombinant viruses into mice demonstrated that a major determinant of TMEV neurovirulence is within the GDVII 1B (capsid protein VP2)-2C coding region, most likely in the GDVII 1B (VP2)-2A coding region. Genomic sequences 5' to this region of GDVII RNA also contribute to expression of the full neurovirulence phenotype. These data demonstrate the multigenic nature of TMEV neurovirulence, as has been reported for other viruses.

Amino Acid Sequence↗
PubMed1990

The principle of parsimony: Glasgow Coma Scale score predicts mortality as well as the APACHE II score for stroke patients.

Although the development and use of severity-of-illness measures has gained widespread enthusiasm, uncertainty remains as to the optimal measure for stroke patients. The Health Care Financing Administration recently derived a severity-of-illness measure based on the APACHE II system to explain differences in Medicare mortality rates among hospitals treating stroke patients. We hypothesized that the Glasgow Coma Scale score provides prognostic information of accuracy comparable to that of the APACHE II score for stroke patients, yet is simpler and cheaper to abstract from the medical record. We therefore studied 246 patients hospitalized with stroke, including 49 oversampled mortalities. The Glasgow Coma Scale score was as accurate as the APACHE II score in predicting stroke mortality both before (r = -0.50 and r = 0.50, respectively) and after (r = -0.40 and r = 0.38, respectively) the oversampled mortalities were excluded. The APACHE II score required abstraction of 16 variables from the medical record compared with three for the Glasgow Coma Scale score and required more than three times the time to abstract from the medical record. Therefore, in the interest of parsimonious data collection, the Glasgow Coma Scale may be a preferable severity-of-illness measure for patients with stroke.

Aged↗