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Biomedical subjects

M Singer

Publications and source records attributed to M Singer.

At least 145 records · Page 8Linked to original sources
PubMed1994

Cardiovascular performance and core temperature during transurethral prostatectomy.

Hemodynamic performance and core temperature were recorded during transurethral prostatectomy in 52 patients who were stratified according to cardiac symptom score and then randomized to undergo standard (31) or isothermic (21) transurethral prostatectomy. During the standard procedure ambient temperature (21C) irrigant was used, while during isothermic prostatectomy warmed irrigant at 38C was used to prevent heat loss from the bladder, and a warming blanket and humidifying filter were used to decrease cutaneous and respiratory heat loss. Core temperature decreased by a mean of 0.8C (95% confidence interval -0.9 to -0.7) during standard transurethral prostatectomy and by 0.27C (-0.4 to -0.15) during the isothermic procedure. The standard prostatectomy group showed a significant hemodynamic response consisting of increased mean arterial pressure (p < 0.0002), increased index of systemic vascular resistance (p < 0.0001), bradycardia (p < 0.02), and decreased Doppler indexes of stroke volume (p < 0.005) and cardiac output (p < 0.001). The isothermic transurethral prostatectomy group was hemodynamically stable. These differences between the groups suggest that rapid central cooling exerted a significant effect on perioperative hemodynamic performance during transurethral prostatectomy.

Aged↗
PubMed1994

Novel bishydroxamic acids as 5-lipoxygenase inhibitors.

Two series of novel bishydroxamic acids 2 and 3 (types A and B) were synthesized and tested for inhibition of 5-lipoxygenase from rat basophile leukemia (RBL) cells. Both series were potent inhibitors of the isolated enzyme but only the type B reverse hydroxamic acids possessed significant oral activity. The most potent compound, orally, was 3a, [IC50 = 270 nM; ED50 = 1.86 mg/kg], which compares favorably with the clinically useful 5-lipoxygenase inhibitor, zileuton. Unlike known hydroxamic acid inhibitors, the oral activity in this series appears to be associated with the second hydroxamic acid group. The corresponding monohydroxamic acids retained inhibitor potency, in vitro, with reduced oral activity in a mouse zymosan peritonitis model. Compound 4e [IC50 = 7 nM], a monohydroxamic acid derivative related to 3a, is among the most potent inhibitors of the isolated enzyme yet to be reported.

Animals↗
PubMed1994

Constructing inferences during narrative text comprehension.

The authors describe a constructionist theory that accounts for the knowledge-based inferences that are constructed when readers comprehend narrative text. Readers potentially generate a rich variety of inferences when they construct a referential situation model of what the text is about. The proposed constructionist theory specifies that some, but not all, of this information is constructed under most conditions of comprehension. The distinctive assumptions of the constructionist theory embrace a principle of search (or effort) after meaning. According to this principle, readers attempt to construct a meaning representation that addresses the reader's goals, that is coherent at both local and global levels, and that explains why actions, events, and states are mentioned in the text. This study reviews empirical evidence that addresses this theory and contrasts it with alternative theoretical frameworks.

Cognition↗
PubMed1994

Pharyngoesophageal reconstruction using the radial forearm fasciocutaneous free flap: preliminary results.

Pharyngoesophageal reconstruction remains a challenge to the head and neck surgeon. The goals of pharyngoesophageal reconstruction include restoration, with minimal morbidity, of a person's ability to swallow and to speak. Myocutaneous flaps, gastric pull-up, and the jejunal free flap are popular methods of pharyngoesophageal reconstruction; however, none of these modalities is clearly ideal. We have begun utilizing the radial forearm fasciocutaneous free flap for pharyngoesophageal reconstruction. Twelve patients have had reconstruction with this flap with follow-up from 2 to 15 months. Seven defects were circumferential, and five were noncircumferential. Ten patients (83%) have had successful restoration of both swallowing ability and voice. Donor site morbidity was minimal. The leading complication was salivary leak, which was present in eight (67%) patients. Five of the leaks closed with nonsurgical intervention. No cases of flap necrosis occurred. The radial forearm free flap is a thin and pliable flap that closely approximates the tissue consistency of normal pharynx. Successful restoration of a patient's ability to swallow approximates that of enteral flaps and is superior to that of MC flaps. Successful speech restoration is superior to that of enteral and MC flaps. Donor site morbidity is less than that caused by enteral flaps because laparotomy is avoided. Salivary leak is higher than with enteral flaps. Part of this difference is accountable to the high number of secondary and technically challenging reconstructions in this series, and we have taken steps to lower this rate of leakage. These preliminary data show that the radial forearm fasciocutaneous free flap is well suited for pharyngoesophageal reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Hemodynamic effects of manual hyperinflation in critically ill mechanically ventilated patients.

SUBJECT OBJECTIVE: To assess the hemodynamic effects of manual lung hyperinflation in mechanically ventilated patients and to measure the different inspiratory pressures and tidal volumes generated by different operators. DESIGN: Measurements of aortic blood flow (by esophageal Doppler ultrasonography), systemic blood pressure, tidal volumes (by respirometry), and inspiratory pressures in the ventilator circuit were measured on the ventilator, during six intended manual hyperinflations (tidal volume > 150% that delivered by ventilator) using a 2-L rebreathing bag, and at 1, 5, 10, and 15 min after reconnection to the ventilator. SETTING: Intensive care unit. PATIENTS: Eighteen mechanically ventilated patients with normovolemia and stable circulatory status were assessed on a total of 20 occasions. INTERVENTIONS: Patients were disconnected from the ventilator to enable six manual hyperinflations to be given. Measurements were made before and at 5-min intervals until no further hemodynamic changes were seen. MEASUREMENTS AND RESULTS: Hyperinflation (50% increase in tidal volume) was achieved only in 10 of 20 studies. Large variations were seen in percentage change in peak inspiratory pressure (-30% to +250%) and tidal volume (-33% to +127%) generated. Falls in cardiac output correlated to the increase in tidal volume but not to the increase in peak inspiratory pressure and took up to 15 min to recover to baseline values. Changes in cardiac output were independent of lung compliance and concurrent vasoactive drug support. No consistent change was noted in either blood pressure or heart rate. CONCLUSIONS: Lung hyperinflation is frequently not achieved by the manual technique. Significant changes in cardiac output can occur and appear to be related to the tidal volume rather than pressure generated.

Adult↗
PubMed1994

Dracula. Disorders of the self and borderline personality organization.

It has been proposed that Bram Stoker's novel Dracula can best be understood as a dramatic, hyperbolic, and fantastic expression of themes consistent with contemporary psychoanalytic conceptions of borderline personality disorder organization. Such an understanding may, in turn, shed further light on the nature of the intrapsychic world and experiences of borderline patients. Excerpts from the novel can be used to support the conceptualization of recent contributions to object relations theory and the understanding of borderline personality organization. It is uncanny how consistent Dracula's characteristics are to the generally seen complaints of patients suffering from this disorder.

Borderline Personality Disorder↗
PubMed1994

A profile of specific psychotherapeutic actions for borderline psychopathology. Psychotherapeutic psychoanalysis.

This article has attempted to catalog additions to the psychotherapeutic armamentarium in the treatment of borderline personality disorder based on their conceptual linkage with new paradigms derived from contemporary developments in psychoanalysis. These new therapeutic actions have broadened and increased our therapeutic skills and are now also viewed as essential for bringing about change in patients with severe developmental arrests. The term psychotherapeutic psychoanalysis is suggested to encompass this unique cluster of intrinsic and extrinsic treatment factors within the framework of psychoanalysis.

Borderline Personality Disorder↗
PubMed1993

Genetic evidence for the interaction between cluster I and cluster III rifampicin resistant mutations.

Rifampicin-resistant (Rifr) mutations of Escherichia coli map to the central portion of the rpoB gene, which encodes the beta subunit of RNA polymerase. These mutations are located in three distinct clusters, designated I, II and III. Three intragenic suppressors of the cluster III Rifr mutation, rpoB3406(RH687), restore the ability of the mutant strain to grow at low and high temperatures and map to a single locus in cluster I. These suppressors are identical to two previously characterized Rifr alleles, rpoB3401(RC529) and rpoB3402(RS529). None of the other 14 previously identified Rifr mutations that we have characterized confers this phenotype. We suggest that this allele-specific suppression results from interaction between Cluster I and Cluster III of the beta subunit.

Alleles↗
PubMed1993

Infections due to antibiotic-resistant gram-positive cocci.

Gram-positive cocci are becoming increasingly resistant to traditionally used antimicrobial agents. Staphylococcus aureus, coagulase-negative staphylococci, the enterococcus, and Streptococcus pneumoniae are the most commonly encountered of such pathogens in clinical practice. Clinicians should be keenly aware of the usual types of infections that are caused by these organisms and the importance of documenting susceptibilities of infecting strains. The basic mechanisms of resistance should be familiar to clinicians so that an inappropriate empiric regimen will not be selected (e.g., addition of a beta-lactamase inhibitor for penicillin-resistant pneumococci). Vancomycin remains the agent of choice, sometimes in combination with gentamicin and/or rifampin, for most cases of infection due to these resistant gram-positive organisms. Last, increased efforts toward prevention, such as strict adherence to infection control measures, selective use of broad-spectrum antibiotics, and increased use of pneumococcal vaccine, may be useful to help stem the rising tide of infections due to resistant gram-positive cocci.

Anti-Bacterial Agents↗
PubMed1993

Knowledge for use: anthropology and community-centered substance abuse research.

The anthropological world has changed. The ethnographic Other is no longer available and pliant, awaiting anthropological representation, but has acquired a voice of his/her own. As a result, anthropology is faced with a dilemma. What is to be the anthropological role in this transformed world? Two alternatives are examined. The first, postmodernism, stresses the development of experimental ethnographic texts that inscribe the voice of the transformed Other. Noting the weaknesses of the postmodern 'solution,' this paper proposes community-centered research as a more appropriate response to contemporary social realities. In this approach, the anthropologist seeks collaboration with the Other in the struggle for self-determination. Illustration is provided with the case study of anthropologists employed in a Puerto Rican community based organization (CBO), with specific reference to the emergence and development of the substance abuse prevention and treatment work of this CBO. While noting the difficulties of this role, the paper argues that scholarly activism, a model adopted from the Third World, is well suited to the postmodern world.

Alcoholism↗
PubMed1993

Continuous intravenous infusion of fentanyl: case reports of use in patients with advanced cancer and intractable pain.

The use of continuous intravenous infusion of opioids may be efficacious in managing pain related to advanced cancer. Short-acting opioids, such as morphine and hydromorphone, are commonly used. We describe the use of a fentanyl infusion in four cases. This experience suggests that fentanyl may be considered an alternative drug for infusion in the treatment of refractory cancer pain.

Adult↗
PubMed1993

Psychological distress, problem behaviors, and family functioning of sexually abused adolescent inpatients.

OBJECTIVE: By studying children and adolescents who have been sexually abused, improvements in identifying and treating emerging pathology can be gleaned before personality structures become more rigidly defined and less amenable to therapeutic interventions. It is through studying and comparing subgroups of victims and controls that clinical researchers can additionally elucidate abuse-related manifestations that contribute to the development of psychopathology. METHOD: A group of sexually abused adolescent psychiatric inpatients was compared with a control group of inpatient counterparts on measures of social competence, self-esteem, depression, substance abuse, and perceptions of family characteristics and functioning. Consecutive admissions to an adolescent inpatient psychiatric unit (N = 423) were carefully screened for a history of sexual abuse, then divided into two groups, each with 87 subjects, after matching on key variables including age, race, gender, socioeconomic status, and psychiatric diagnosis. RESULTS: Sexually abused and control group inpatient adolescents were similar on standardized measures of psychological distress and family functioning. Statistically significant differences were found between groups on substance abuse measures. CONCLUSION: The phenomenology of the relationship between sexual abuse and substance abuse and the implications for inpatient treatment are summarized.

Adolescent↗
PubMed1993

Intensive care.

Explore the source record for details and available documents.

Critical Care↗
PubMed1993

The optimal time for measuring the cardiorespiratory effects of positive end-expiratory pressure.

No study has elucidated the minimum time taken for oxygen delivery to reach steady-state levels after an increase in positive end-expiratory pressure (PEEP). We therefore investigated ten ventilated patients who received a total of 27 increments in PEEP of 5 cm H2O. Cardiorespiratory parameters were measured at baseline, at 1 min, and thereafter at 5-min intervals until 2 consecutive measurements of oxygen delivery were constant. Cardiac output was measured continuously using an esophageal Doppler transducer. The PEEP was increased to a maximum of 20 cm H2O or until oxygen delivery fell by 15 percent. Increases in PEEP were always associated with increases in oxygen saturation. Cardiac output decreased in the majority of cases, the greatest falls occurring in the first minute after an increase in PEEP, and with higher levels of PEEP. No significant changes in oxygen delivery occurred after 15 min. We therefore recommend that 15 min be allowed to elapse after an increase in PEEP before oxygen delivery is reassessed.

Adult↗
PubMed1992

Haemodynamic evidence for cardiac stress during transurethral prostatectomy.

OBJECTIVE: To compare haemodynamic performance during transurethral prostatectomy and non-endoscopic control procedures similar in duration and surgical trauma. DESIGN: Controlled comparative study. SETTING: London teaching hospital. PATIENTS: 33 men aged 50-85 years in American Society of Anesthesiologists risk groups I and II undergoing transurethral prostatectomy (20), herniorrhaphy (eight), or testicular exploration (five). MAIN OUTCOME MEASURES: Percentage change from baseline in mean arterial pressure, heart rate, Doppler indices of stroke volume and cardiac output, and index of systemic vascular resistance, and change from baseline in core temperature. RESULTS: In the control group mean arterial pressure fell to 11% (95% confidence interval -17% to -5%) below baseline at two minutes into surgery and remained below baseline; there were no other overall changes in haemodynamic variables and the core temperature was stable. During transurethral prostatectomy mean arterial pressure increased by 16% (5% to 27%) at the two minute recording and remained raised throughout. Bradycardia reached -7% (-14% to 1%) by the end of the procedure. Doppler indices of stroke volume fell progressively to 15% (-24% to -6%) below baseline at the end of the procedure, and the index of cardiac output fell to 21% (-32% to -10%) below baseline by the end of the procedure. The index of systemic vascular resistance was increased by 28% (17% to 38%) at two minutes, and by 46.8% (28% to 66%) at the end of the procedure. Core temperature fell by a mean of 0.8 (-1.0 to -0.6) degrees C. Significant differences existed between the two groups in summary measures of mean arterial pressure (p less than 0.05), Doppler indices of stroke volume (p less than 0.005) and cardiac output (p less than 0.005), index of systemic vascular resistance (p less than 0.0005), and core temperature (p less than 0.0001). CONCLUSIONS: Important haemodynamic disturbances were identified during routine apparently uneventful transurethral prostatectomy but not during control procedures. These responses may be related to the rapid central cooling observed during transurethral prostatectomy and require further study.

Aged↗
PubMed1992

Anomalous effect of mazindol on dopamine uptake as measured by in vivo voltammetry and microdialysis.

The effect of mazindol on the dopamine (DA) uptake system in the rat striatum was studied by in vivo voltammetry and microdialysis. An increase in the maximal uptake rate was observed by voltammetry 30 min after i.p. administration of 1, 5, 10, 15, and 20 mg/kg doses but not after a dose of 25 mg/kg, while stimulated release was enhanced at all doses. The increased maximal uptake is in contrast to increased levels of extracellular DA observed with microdialysis following mazindol administration. This divergence of action is anomalous in the context of current understanding of the DA uptake system.

Animals↗