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Biomedical subjects

R Rogers

Publications and source records attributed to R Rogers.

At least 127 records · Page 7Linked to original sources
PubMed1992

Differentiation between monomorphic ventricular tachycardia and sinus tachycardia based on the right ventricular evoked potential.

The differentiation between ventricular tachycardia (VT) and sinus tachycardia (ST) is problematic in some patients with implantable defibrillators and/or antitachycardia pacemakers. The integral of the ventricular endocardial evoked response, or paced depolarization integral (PDI), has been demonstrated to undergo characteristic changes with a variety of stimuli including catecholamines, pacing rate, and exercise. We hypothesized that the PDI recorded from a unipolar transvenous right ventricular endocardial catheter would differentiate VT from ST. The PDI was calculated from a unipolar pacing stimulus, delivered via a cathode in the right ventricular apex, and the reference electrode, a quadripolar catheter positioned in the superior vena cava. PDIs were measured in 22 patients during VT and sinus rhythm. The PDI measured during sinus rhythm was 579 +/- 240 microV-sec and the PDI during VT was 894 +/- 411 microV-sec (P < 0.001). In a subset of seven patients, PDIs were measured during VT, sinus rhythm, and ST induced by catecholamine infusion or exercise. In this subset, the PDI during sinus rhythm was 645 +/- 295 microV-sec, during ST 588 +/- 308 microV-sec (9% decrease from sinus, P = 0.05), and during VT 863 +/- 342 microV-sec (33.9% increase, P = 0.01). These data indicate that the measurement of the PDI is potentially useful in differentiating VT from ST.

Algorithms↗
PubMed1992

Cloning of an Erwinia herbicola gene necessary for gluconic acid production and enhanced mineral phosphate solubilization in Escherichia coli HB101: nucleotide sequence and probable involvement in biosynthesis of the coenzyme pyrroloquinoline quinone.

Escherichia coli is capable of synthesizing the apo-glucose dehydrogenase enzyme (GDH) but not the cofactor pyrroloquinoline quinone (PQQ), which is essential for formation of the holoenzyme. Therefore, in the absence of exogenous PQQ, E. coli does not produce gluconic acid. Evidence is presented to show that the expression of an Erwinia herbicola gene in E. coli HB101(pMCG898) resulted in the production of gluconic acid, which, in turn, implied PQQ biosynthesis. Transposon mutagenesis showed that the essential gene or locus was within a 1.8-kb region of a 4.5-kb insert of the plasmid pMCG898. This 1.8-kb region contained only one apparent open reading frame. In this paper, we present the nucleotide sequence of this open reading frame, a 1,134-bp DNA fragment coding for a protein with an M(r) of 42,160. The deduced sequence of this protein had a high degree of homology with that of gene III (M(r), 43,600) of a PQQ synthase gene complex from Acinetobacter calcoaceticus previously identified by Goosen et al. (J. Bacteriol. 171:447-455, 1989). In minicell analysis, pMCG898 encoded a protein with an M(r) of 41,000. These data indicate that E. coli HB101(pMCG898) produced the GDH-PQQ holoenzyme, which, in turn, catalyzed the oxidation of glucose to gluconic acid in the periplasmic space. As a result of the gluconic acid production, E. coli HB101(pMCG898) showed an enhanced mineral phosphate-solubilizing phenotype due to acid dissolution of the hydroxyapatite substrate.

Acinetobacter calcoaceticus↗
PubMed1992

Screening psychiatric patients for Axis II disorders.

This study examined the usefulness of the SCID-PQ on a sample of 82 inpatients as a screening measure for Axis II disorders. The SCID-PQ proved effective (i.e., resulted in a very low false negatives and moderate false positives) in screening for seven of the 11 DSM-III-R personality disorders. Of the four remaining disorders, minor modifications were suggested which resulted in improved classification rates for dependent and schizoid personality disorders.

Hospitalization↗
PubMed1992

The future of refugee flows and policies.

"The number of forced migrants...is estimated today to exceed 40 million [worldwide]. The changed international climate of the 1990s...has shifted the focus from the asylum and resettlement countries to the countries of origin: there is today a greater willingness to intervene in other countries' affairs either to avert the creation of new flows of focused migrants or to assist internally displaced populations, and there is the expectation of large-scale voluntary returns of refugees in asylum. This article discusses these and other policy issues concerning forced migration in this new international environment."

Demography↗
PubMed1992

Improvements in the M test as a screening measure for malingering.

Recent studies of the M have failed to confirm its effectiveness as a screening measure for malingering. The present study involved a further analysis of 99 cases reported by Gillis et al. and the construction of Rule-Out and Rule-In scales. Both scales evidence excellent internal reliability, and their combined use was effective in accurately screening greater than 80 percent of potential malingerers.

Disability Evaluation↗
PubMed1991

Utility of adenosine administration during intraoperative mapping in a patient with the Wolff-Parkinson-White syndrome.

Adenosine is an endogenous nucleoside that is administered intravenously and has potent chronotropic and dromotropic effects. This drug is distinguished from verapamil by its very short half-life. This makes it an ideal agent for use in the operating room where long lasting electrophysiological effects may not be desirable. A 61-year-old man with preexcited atrial fibrillation was referred for surgical ablation of his accessory pathway. Preexcitation was minimal or absent on arrival in the operating room. Intravenous adenosine was given causing AV nodal block, and resulted in marked preexcitation, thus allowing computerized mapping to localize the site of the accessory pathway. Adenosine may be a useful agent for rapid and precise localization of accessory pathway(s) in a select group of patients with minimal preexcitation at the time of surgery. Its short half-life allows additional mapping without sustained electrophysiological effects on the AV node, or accessory pathway.

Adenosine↗
PubMed1991

A prospective comparison of four insanity defense standards.

OBJECTIVE: Controversy about the formulation of the insanity defense has been intense, but little empirical work is available regarding how different standards affect court findings. The major aims of the present study were to determine if different standards for determining insanity produced different judgments and to provide a broad descriptive picture of those cases in which the standards appeared to make a difference. METHOD: Four forensic psychiatrists were asked to indicate whether they thought 164 defendants met any or all of four insanity tests: 1) the American Law Institute (ALI) cognitive criterion, 2) the ALI volitional criterion, 3) the APA test, and 4) the M'Naghten rule. RESULTS: The four psychiatrists determined that 97.5% of the defendants met the ALI volitional criterion, 73.9% met the APA criterion, 70.3% met the M'Naghten rule, and 69.5% met the ALI cognitive criterion. Nearly two-thirds of the defendants met all four insanity tests, and 24.4% met only the ALI volitional test. Few defendants met cognitive tests without also meeting the ALI volitional test. Elimination of the volitional test for insanity reduced the rate of psychiatric recommendations of acquittal by 24.4%. CONCLUSIONS: These findings highlight the fact that the primary logical division between volitional and cognitive standards appears to be powerful but that distinctions between types of cognitive standards are not terribly powerful. In addition, the variation among individual raters must be viewed as an important determinant of how any insanity standard is applied.

Adolescent↗
PubMed1991

The role of Canadian psychiatry in dangerous offender testimony.

Psychiatrists and psychologists who participate in dangerous offender hearings are accorded "expert status" by the courts for the long term prediction of violent recidivism. The clinical and judicial bases for such involvement are reviewed and critiqued. Given the frailties of our predictive abilities, the most prudent course would be for mental health experts to eschew dangerous offender determinations. Since this alternative appears unlikely, tentative guidelines are offered to reduce grave errors in testimony given at dangerous offender hearings.

Commitment of Persons with Psychiatric Disorders↗
PubMed1991

Validity of the M Test: simulation-design and natural-group approaches.

The utility of the M Test (Beaber, Marston, Michelli, & Mills, (1985) as a screening measure for malingering was assessed using simulation-design (subjects asked to fake mental illness) and natural-group (forensic assessment cases suspected of malingering) approaches. A total of 318 subjects from community, clinical, and correctional settings completed the M Test under instructions to respond honestly or to simulate a major mental disorder. A factor analysis of the M Test items supported the original rationally based scale assignment, and the scales were found to have adequate internal reliability. To examine the predictive validity of the M Test, results revealed that sensitivity using the cutting scores suggested by Beaber et al. (1985) was much higher for simulating subjects (79.8%) than for the suspected malingerers (40.0%). The findings emphasize the danger of exclusive reliance on simulation studies for validating measures of malingering. It was concluded that, in its present form, the M Test does not constitute a good screening measure for assessing malingering.

Adult↗
PubMed1991

Rethinking the DSM III-R diagnosis of antisocial personality disorder.

The diagnosis of antisocial personality disorder (APD) has undergone substantive revisions in the DSM III and DSM III-R criteria. Within the context of these modifications, the authors reviewed the current research and psychometric models of APD. They found considerable variability among these models which in turn appear to be only modestly correlated with DSM standards. Recommendations are offered to reduce symptom variations subsumed within APD and to explore a reformulation of APD for achieving greater congruence with research findings.

Antisocial Personality Disorder↗
PubMed1990

The clinical presentation of command hallucinations in a forensic population.

In a forensic population, patients with command hallucinations (N = 25) were compared to two groups of psychotic patients: those with noncommand hallucinations (N = 24) and those without hallucinations (N = 16). The three groups did not differ in overall impairment as measured by the Global Assessment Scale and the Social Behavior Rating Schedule. However, the group with command hallucinations differed in the content of their hallucinations (more aggression, dependency, and self-punishment themes), and nearly one-half did not report or denied their command hallucinations to the assessment team. Many patients (N = 11, 44%) reported that they frequently responded to hallucinatory commands with unquestioning obedience.

Adult↗
PubMed1990

Nutritional requirements in the elderly.

Nutritional management of elderly persons can be difficult because of illness, drug-nutrient interactions, socioeconomic factors, and lack of precise information regarding nutrient requirements. Dietary intake and requirements, nutritional assessment, and guidelines for nutritional management of the elderly population are reviewed.

Adult↗
PubMed1990

Development of a new classificatory model of malingering.

Inclusion criteria for the classification of malingering are shaped and largely predetermined by our explanatory theories. Current theories have postulated the motivation to malinger is either the product of underlying psychopathology (pathogenic model) or criminal backgrounds (DSM III-R model). I have proposed a third model that malingering is typically an adaptive response to adverse circumstances which may best be understood in the context of decision theory. Based on this approach I have argued that indices of malingering should be empirically derived and focused on clinical presentation. Finally, I have proposed a preliminary model for the classification of malingerers which combines clinical data with corroborative evidence.

Antisocial Personality Disorder↗
PubMed1989

Pharmacological characterization of conduction over a Mahaim fiber: evidence for adenosine sensitive conduction.

The presence of a nodoventricular pathway (Mahaim fiber) has been invoked to explain certain distinctive electrocardiographic and electrophysiological observations. The presence of an atrioventricular or atriofascicular fiber with decremental conduction properties has been documented in many of these patients. We report the case of a patient with a Mahaim fiber and the response to conduction over this pathway after adenosine, procainamide, encainide, verapamil, edrophonium, phenylephrine and isoproterenol. Conduction over the Mahaim fiber was blocked by adenosine, but not verapamil. The time course of adenosine induced block over the Mahaim fiber differed from adenosine induced AV nodal block. Mahaim fibers are decrementally conducting pathways that are adenosine sensitive. These findings support the concept that conduction in accessory pathways manifesting decremental properties is not mediated by the calcium channel.

Adenosine↗
PubMed1989

Diagnostic legitimacy of factitious disorder with psychological symptoms.

The authors question the clinical status of factitious disorder with psychological symptoms as a mental disorder. In particular, they argue that unresolved issues regarding the motivational basis of this disorder and the lack of clearly delineated inclusion, exclusion, and outcome criteria seriously compromise its diagnostic legitimacy. Two case reports are presented to illustrate these difficulties. Future studies should consider these empirical and conceptual difficulties in refining the diagnosis of factitious disorder with psychological symptoms for DSM-IV.

Adult↗