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Biomedical subjects

A Roth

Publications and source records attributed to A Roth.

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

Delirium associated with the combination of a neuroleptic, an SSRI, and benztropine.

BACKGROUND: On the basis of recent findings, the increased use of serotonin selective reuptake inhibitors (SSRIs) in combination with antipsychotics and concomitant benztropine is likely. METHOD: Five patients who developed delirium while receiving a neuroleptic, an SSRI, and benztropine are described. RESULTS: The timing of the delirium in relation to drug administration suggests the delirium was the result of an interaction of the SSRI and benztropine. CONCLUSION: Possible mechanisms are explored. Clinicians should be aware that patients receiving this combination may be at increased risk for delirium.

Aged↗
PubMed1994

A versatile plasmid vector system for the regulated expression of genes in Escherichia coli.

A series of plasmid expression vectors, which support the regulated and efficient expression of genes in Escherichia coli, have been constructed. The vectors consist of a DNA replication origin cassette, a promoter cassette, an efficient ribosome binding site together with a polylinker region and a lacZ gene. Several types of replication origins and promoter sequences are each available on cassettes. Fusion of the 5' TG dinucleotide of the gene under consideration to the A nucleotide, present on the vector, results in an ATG start codon and allows, in combination with the plasmid-borne ribosome binding site, the efficient expression of the cloned gene. Additionally, a second fusion of the gene at its 3' end with the lacZ gene, which is available in all three reading frames relative to the polylinker region, allows rapid selection of the correctly fused genes. As an example of the cloning of a regulatory gene, this vector system was used for the expression of the dnaA gene, of Escherichia coli, the initiator protein for DNA replication.

Bacterial Proteins↗
PubMed1993

Kinetic properties of pure overproduced Bacillus subtilis phenylalanyl-tRNA synthetase do not favour its in vivo inhibition by ochratoxin A.

Ochratoxine A (OTA) inhibits growth of Bacillus subtilis at pHs below 7. Since OTA is a phenylalanine analogue, this effect could be due to inhibition of phenylalanine-tRNA synthetase (PheRS) by competition of this mycotoxin with the amino acid. Homogeneous PheRS was purified from Bacillus subtilis and from E. coli transformed with the PheRS gene. The latter produced about 40 times more PheRS than B. subtilis. The Km and Ki values of PheRS, respectively, for phenylalanine and OTA were measured and their concentrations within the cell determined. It appears that the concentration of OTA in the cell, in spite of a 25-fold accumulation, remained too low to significantly compete with phenylalanine. This does not suggest PheRS to be the target of OTA in cell growth and protein synthesis inhibition in Bacillus subtilis. It was also shown that the 2-3-fold increase of PheRS in OTA-treated cells is not due to phenylalanine-controlled attenuation regulation.

Bacillus subtilis↗
PubMed1993

Regenerative outgrowth and distribution of the electroreceptive nerve fibers in the catfish Kryptopterus.

The ampullary electroreceptors on the trunk of Kryptopterus bicirrhis are induced and continuously maintained by a trophic substance released by their afferent nerve fibers. When the fibers are transected and the proximal stumps deflected to a new place, the regenerating fibers grow along new routes to the old electroreceptor sites and again induce organs there. The new routes consist of two sections. The first goes from the deflected stump end to other nearby running intact or degenerated nerves and fibers. In the second section, the regenerating fibers grow along these nerves and fibers to their distal ends, i.e., to the old electroreceptor sites. If the path-guiding nerves and fibers are experimentally removed, the displaced fibers grow to the normal receptor areas directly. Growing out from the displaced stump, they spread out over the trunk in a pattern similar to the pattern displayed formerly by the original nerve fibers at this place. It is concluded that the outgrowing fibers do not possess a specificity for a certain receptor site or skin area, but spread out according to epigenetic factors in the periphery.

Animals↗
PubMed1993

A randomized comparison between the hemodynamic effects of hydralazine and nitroglycerin alone and in combination at rest and during isometric exercise in patients with chronic mitral regurgitation.

Both arteriolar vasodilation with hydralazine and venodilation with nitroglycerin have been shown to favorably alter the hemodynamic profile in patients with chronic mitral regurgitation. Since these therapeutic modalities exert their effects by different mechanisms, this study was designed to assess hemodynamic response to both drugs given individually and in combination at rest and during isometric exercise in patients with chronic mitral regurgitation of various etiologies. When used individually, hydralazine caused larger increase in heart rate, cardiac index, stroke volume index, and systemic vascular resistance both at rest and during exercise. In contrast, nitroglycerin administration was associated with a superior effect on mean pulmonary artery pressure and V wave amplitude at rest and on mean right atrial and mean pulmonary artery wedge pressures at rest and during isometric exercise. In comparison with hydralazine alone, combination therapy enhanced the reduction in right atrial pressure (4 +/- 1 versus 0 +/- 2 mm Hg, p < 0.05), mean pulmonary arterial pressure (11 +/- 5 versus 1 +/- 3 mm Hg, p < 0.05), and the V wave amplitude (15 +/- 6 versus -5 +/- 3 mm Hg, p < 0.05) at rest and resulted in a larger reduction in exercise values of mean pulmonary artery pressure (-11 +/- 7 versus -3 +/- 5 mm Hg, p < 0.05) and mean pulmonary arterial wedge pressure (-11 +/- 5 versus -5 +/- 3 mm Hg, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Wnt-5a and Wnt-7a are expressed in the developing chick limb bud in a manner suggesting roles in pattern formation along the proximodistal and dorsoventral axes.

The Wnt gene family encodes a group of secreted signalling molecules that have been implicated in the regulation of cell fate and pattern formation during embryogenesis. We have examined the patterns of expression of two members of the chicken Wnt family, Wnt-5a and Wnt-7a, during development of the chick limb bud. Wnt-5a is expressed in the apical ectodermal ridge which directs outgrowth of limb mesoderm. Wnt-5a also exhibits three quantitatively distinct domains of expression along the proximodistal (PD) axis of the limb mesoderm that may correspond to the regions which will give rise to the three distinct PD segments of the limb, the autopod, zeugopod, and stylopod. In contrast, Wnt-7a expression in the limb bud is specifically limited to the dorsal ectoderm. These observations suggest possible roles for Wnt-5a and Wnt-7a in pattern formation along the PD and dorsoventral axes of the developing chick limb bud. In addition, Wnt-5a and Wnt-7a exhibit spatially discrete domains of expression in several other regions of the chick embryo consistent with developmental roles for these genes in a variety of other tissues.

Amino Acid Sequence↗
PubMed1993

Time-consuming procedures and prehospital thrombolytic treatment.

OBJECTIVES: To assess time-consuming procedures in the prehospital stage of acute myocardial infarction patients who had received thrombolytic therapy at the scene, and to evaluate their effect on the clinical outcome. DESIGN: Prospective study. SETTING: Mobile intensive care unit staffed by an intern or a hospital-based physician. PARTICIPANTS AND INTERVENTIONS. Thrombolytic therapy with recombinant tissue-type plasminogen activator (total dose of 120 mg/6 hrs) was initiated at the scene in 167 patients. Treatment continued during transportation and thereafter in the cardiac care unit. During hospitalization, radionuclide ventriculograms and coronary angiography were performed in most patients. MEASUREMENTS AND MAIN RESULTS: Correct diagnosis was confirmed in 165 of 167 patients. Mean time to treatment was 96 +/- 42 (SD) mins with no significant difference between patients treated at home (n = 105) or in public places (n = 60). Global duration of treatment was significantly shorter when thrombolytic therapy was given in public as compared with treatment applied at home (50 +/- 13 vs. 57 +/- 16 mins, respectively, p < .002). CONCLUSION: If patients and physicians become aware of the potential advantages of prompt initiation of thrombolytic therapy at the scene, critical time may be saved in delivering thrombolysis to the clotted coronary artery.

Emergency Medical Services↗
PubMed1993

Rapid resolution of new right bundle branch block in acute anterior myocardial infarction patients after thrombolytic therapy.

The objectives of this retrospective study are to describe the effect of thrombolytic treatment on the clinical course of patients with acute anterior myocardial infarction complicated by acute right bundle branch block. Patients admitted to the intensive cardiac care unit within < 4 hours from onset of symptoms, and demonstrating an acute right bundle branch block with, or without left axis deviation, on the qualifying ECG were included. All were given intravenous thrombolytic treatment consisting of: streptokinase (1,500,000 IU/40 min) or recombinant tissue type plasminogen activator (120 mg/6 hours). Following admission, patients were continuously monitored and a 12-lead ECG was recorded during each of the first 3 hours and then every 3 hours over the next 21 hours. Eight patients were included (8/211 = 3.8%). Their mean age was 62 +/- 7 years and time elapse from onset to treatment was 122 +/- 26 minutes. Complete resolution of the right bundle branch block occurred within < 3 hours in all and left axis deviation normalized in two patients. Mean peak creatine kinase was 1214 +/- 604 IU and global left ventricular ejection fraction, measured by isotope ventriculography within 24 hours from admission, was 39% +/- 15%. Only one patient was prophylactically paced. In the others, rapid normalization of the conduction block with reperfusion exceeded the logistics required for the transvenous pacemaker implantation procedure. Coronary angiography performed in six patients during 72 hours from admission revealed high grade stenoses in the proximal portion of the left anterior descending coronary artery in five patients and complete occlusion in one.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗
PubMed1993

Postexercise syncope: evidence for increased activity of the sympathetic nervous system.

This report describes an association of postexertional syncope with increased levels of circulating catecholamines. A 36-year-old male who experienced postexercise bradycardia and asystole had higher basal plasma norepinephrine (120 versus 68 +/- 6 pg/ml) and epinephrine (18 versus less than 10 pg/ml) but a similar vagal tone (vagal tone index of 5.44 versus 5.81 +/- 1.00 U) when compared with 6 closely matched subjects who underwent an uneventful stress test.

Adult↗
PubMed1993

[Impact of Shahal (Cardiac Emergency Services) on daily life of subscribers].

SHAHAL (Cardiac Emergency Services) provides professional 24-hour mobile emergency medical service monitored by intensive care nurses via a central computerized operations unit. All subscribers carry a "cardiobeeper" for transtelephonic transmission of a 3-lead electrocardiogram, and an automatic intramuscular self-injector containing 300 mg lidocaine. In this retrospective study we assessed the impact of SHAHAL on subscribers' mental stress, self-confidence and ultimately, quality of life. Answers to a written questionnaire (n = 1034) and a personal interview (n = 55) were analyzed. It was shown that SHAHAL is effective in decreasing mental stress and improving self-confidence in the majority of subscribers. It was especially beneficial in women, the elderly, those of lower socioeconomic status, pessimists and chronic worriers, and the ill more than the healthy. Those whose functional capacities were very limited benefited less, but for them SHAHAL's function as a life-saving and rescue system is more valuable. Lastly, subscription to SHAHAL also improved the self-confidence of the subscriber's family.

Aged↗
PubMed1993

Hospital admissions of young children for status asthmaticus in Honolulu, Hawaii, 1986 to 1989.

Asthma admissions of children aged 5 years or younger to the Kaiser Foundation Hospital in Honolulu were analyzed for the years 1986-1989. Admissions increased at an annual rate of 4.5% during the study period, in agreement with a worldwide trend. Most children wheezed before their first admission, but their diagnosis was bronchitis rather than asthma. This shows that physicians find it difficult to diagnose asthma in young children. Pneumonia was the initial diagnosis in 25% of admissions, mainly due to overinterpretation of chest radiographs, and this contributed to the overuse of antibiotics. Inpatient treatment with inhaled and systemic bronchodilators and anti-inflammatory agents conformed to standard practice. Recent adoption of the guidelines by the National Asthma Education program and the establishment of an outreach program and asthma register should promote more appropriate outpatient treatment and a reduction of admissions for asthma.

Asthma↗
PubMed1993

[Insertion of the Tenon capsule onto the rectus muscles].

The localisation and definition of the capsule of Tenon insertion on the rectus muscles is of prime importance to the strabismus surgeon. The depth of the superior sub-Tenon space was measured on 22 adult human eyes after fixation in formalin. Although the measurements revealed major differences between the eyes, the following results were found: inferior rectus muscle = 7.8 mm +/- 1.79 (5.2-13.0), medial rectus = 12.6 mm +/- 2.15 (8.4-17.2), superior rectus muscle = 16.7 mm +/- 2.39 (12.7-21.5), and lateral rectus muscle = 19.0 mm +/- 2.19 (14.5-22.0). Histological studies of 2 other human eyes confirmed the notion of a band of insertion on rectus muscles as the posterior limit of the sub-Tenon space. As far as this insertion, the capsule of Tenon is a dense connective tissue composed of many collagen and elastin fibers, but after the band insertion, it becomes virtual through its fusion with the perimysium of the rectus muscle.

Adult↗
PubMed1992

Clonidine for patients with rapid atrial fibrillation.

OBJECTIVE: To determine whether clonidine can slow ventricular rate in patients with rapid atrial fibrillation. DESIGN: Randomized, controlled trial, with a 4-hour follow-up period. SETTING: Emergency room of a university hospital. PATIENTS: A consecutive sample of 18 hemodynamically stable patients who were evaluated or treated for rapid atrial fibrillation. Exclusion criteria included acute or terminal illness; current use of antiarrhythmic agents, calcium-channel blockers, or beta-blockers; excessive hypertension; pulmonary, valvular, or pericardial disease; and electrolyte imbalance. INTERVENTIONS: Patients were randomly assigned to receive either "no treatment" (control group) or clonidine, 0.075 mg orally, at baseline and after 2 hours if heart rate did not decrease by at least 20%. MEASUREMENTS: Blood pressure was measured by the same nurse in the same arm for 4 consecutive hours, and a full 12-lead electrocardiographic evaluation was done. MAIN RESULTS: Heart rate decreased to below 100 beats/min in eight of nine patients receiving clonidine compared with two of nine patients in the control group. The difference in the mean decreases in heart rate was 38 beats/min (95% CI, 20 to 56 beats/min). Six patients who were treated with clonidine and one patient in the control group reverted to normal sinus rhythm. Systolic blood pressure decreased slightly in both groups, without significant differences. Clinical follow-up was uneventful. CONCLUSION: Low-dose clonidine was an easy, efficient, and effective treatment for patients with rapid atrial fibrillation who were hemodynamically stable.

Adrenergic alpha-Agonists↗
PubMed1992

Safety of pyridostigmine in hypertensive patients receiving beta blockers.

In the last decade, pyridostigmine, a quaternary carbamate that reversibly inhibits the enzyme acetylcholinesterase, was proposed for pretreatment of nerve gas (organophosphate) poisoning. The objective of this study was to assess the cardiovascular effects of pyridostigmine in patients treated with beta blockers. Eight hypertensive patients receiving regular treatment with beta blockers were randomized in a double-blind crossover study to receive pyridostigmine (30 mg 3 times daily) or placebo for 2 days. Heart rate and blood pressure in the supine and standing positions were recorded every 2 hours during the day, and 24-hour Holter monitoring was performed. In addition, a symptom-limited exercise test was performed, and plasma catecholamine levels were determined at rest and at peak exercise. Pyridostigmine, as compared with placebo, did not induce any significant effect on heart rate, plasma catecholamine levels or resting blood pressure. Both systolic and diastolic blood pressures increased in accordance with exercise intensity (p less than 0.01), although a significantly lower diastolic blood pressure was observed when pyridostigmine was used (average decrease 5 mm Hg compared with placebo; p less than 0.01). No clinical adverse reactions were observed, confirming the relative safety of the combination of low-dose pyridostigmine with beta-adrenergic blocking agents.

Adrenergic beta-Antagonists↗
PubMed1992

Application of the polymerase chain reaction in the diagnosis of pulmonary toxoplasmosis in immunocompromised patients.

Bronchoalveolar lavage (BAL) fluid from 47 immunocompromised patients (26 with AIDS and 21 patients on immunosuppressive therapy) was analysed for the presence of Toxoplasma gondii DNA by means of the polymerase chain reaction (PCR). Specific target DNA derived from the B1 and P30 gene of Toxoplasma gondii was detected in BAL fluids from three patients with AIDS (6.4%). Pneumonia as the presenting feature of disseminated toxoplasmosis was confirmed by both clinical findings and by detection of Toxoplasma gondii DNA in blood obtained from two patients. The findings indicate that PCR has potential value in the detection of Toxoplasma gondii as an etiologic agent of atypical pneumonia in immunocompromised patients.

Animals↗