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Biomedical subjects

M Feinberg

Publications and source records attributed to M Feinberg.

At least 37 records · Page 2Linked to original sources
PubMed1995

Alterations in heart rate variability in patients undergoing dobutamine stress echocardiography, including patients with neurocardiogenic hypotension.

Frequency-domain analysis of heart rate variability (HRV) appears to distinguish sympathetic and parasympathetic modulation of heart rate. The effects of acute reflex, as opposed to tonically augmented, cardiac vagal tone on HRV are not clearly defined. Power spectral components of HRV were measured in 36 patients undergoing dobutamine stress echocardiography including during episodes of neurocardiogenically mediated hypotension. The low-frequency (LF; 0.04 to 0.15 Hz) and high-frequency (HF; 0.15 to 0.40 Hz) components of HRV decreased with increasing dose of dobutamine (5 to 40 micrograms/kg/min) in patients whose systolic blood pressure, compared with baseline, remained within 20 mm Hg (normotensive) or increased > or = 20 mm Hg (hypertensive). The ratio of LF/HF became < 1 in the hypertensive group at 30 and 40 micrograms/kg/min of dobutamine. In eight patients in whom apparent neurocardiogenically mediated hypotension developed (decrease in systolic blood pressure > or = 20 mm Hg from baseline), LF and HF measures became significantly higher than those in the patients without hypotension, whereas the LF/HF ratio was unchanged. These findings suggest that the HF component of HRV is a reliable measure of reflex-augmented cardiac vagal activity and lend further support to the importance of parasympathetic modulation of the LF component of HRV.

Aged↗
PubMed1995

Clinical, immunologic, and virologic observations related to human immunodeficiency virus (HIV) type 1 infection in a volunteer in an HIV-1 vaccine clinical trial.

A vaccine breakthrough occurred in a phase 1 clinical trial of a human immunodeficiency virus (HIV) type 1 candidate subunit vaccine. The vaccine antigen, gp120SF2, is a fully glycosylated protein produced in mammalian cells from the HIVSF2 isolate. After 4 immunizations, the subject developed neutralizing antibodies and lymphoproliferative responses to the gp120 protein. About 18 weeks after the last immunization, the subject became HIV infected. During the acute phase of infection, there was high virus burden, a decline in CD4+ T lymphocytes, increases in rgp120SF2-binding antibodies and HIVSF2- and HIVMN-neutralizing antibodies, and transient lymphoproliferative responses to HIV-1 envelope and core proteins. The nucleotide sequence of the V3 loop from 2 virus isolations displayed close similarity to the V3 sequence of the vaccine antigen. Thus, the immunologic responses induced by the vaccine in this subject did not protect him from HIV-1 infection.

AIDS Vaccines↗
PubMed1994

Quantification of left ventricular dimensions on line with biplane transesophageal echocardiography and lateral gain compensation.

To determine the feasibility and accuracy of biplane transesophageal echocardiography (TEE) with automatic boundary detection (ABD) for the estimation of left ventricular areas, we examined 19 consecutive patients with the use of this technique. In addition, we evaluated the utility of lateral gain compensation (LGC) to improve the online tracking of the ABD algorithm on the lateral endocardial-blood boundary of the echocardiographic image. The transverse plane short-axis TEE view and the longitudinal plane two chamber TEE view were used for the analysis. A semiquantitative estimate (in degrees) of the endocardial circumference, in which the boundary was correctly identified and tracked on line, improved from a mean of 198 degrees to 360 degrees with LGC (P less than 0.001). Results of comparisons of offline and online biplane TEE cavity areas revealed excellent correlations of values for the 16 patients (84%) in whom adequate transverse plane short-axis images were obtained (r values greater than 0.9 at systole and diastole). The correlation was also excellent (r values greater than 0.9) in the nine patients in whom longitudinal plane two-chamber views adequate for ABD analysis were obtained at systole and diastole. LGC significantly improved the accuracy of endocardial detection and tracking, which otherwise would be limited due to the anisotropic properties of the myocardium. Thus, ABD during biplane TEE may be feasible in a significant number of patients and accurately reflects left ventricular areas when compared with offline methods.

Echocardiography, Transesophageal↗
PubMed1992

Clinical and demographic data in 75 patients with near-fatal choking episodes.

The clinical background and circumstances of 75 patients who had survived a near-fatal choking episode, i.e., had undergone a Heimlich maneuver, oropharyngeal suctioning, or intubation, is reported. Sixty had choked on a solid bolus (often of a complex texture like sandwiches and chicken soup). Four patients had choked on mashed banana. In 30 patients neurologic disease (such as cerebrovascular disease, Parkinson disease, or dementia) was present. Choking occurred during breakfast (16 patients), lunch (21), dinner (26), and snacks (12). Twenty-five choked at home, 18 in nursing homes, 14 in hospitals, nine in restaurants, and nine in drinking establishments. Twelve were being fed at the time of choking. Fifty-eight of the individuals had oral, pharyngeal, or esophageal abnormalities on radiographic examination that could explain the choking episode. Fourteen patients who were able to vocalize during the choking episode had probably suffered from esophageal impaction. Our study indicates that elderly individuals and those with neurogenic dysphagia are at risk for choking. Dysphagia diet (semisolids) may actually contribute to the risk in these patients. Young adults may also be at risk during episodes of consumption of alcohol and snacks.

Adult↗
PubMed1991

Clomipramine for obsessive-compulsive disorder.

Obsessive-compulsive disorder affects about 2 percent of the U.S. population and can be quite disabling. Clomipramine is the only drug approved for the treatment of obsessive-compulsive disorder. Its efficacy is unique among tricyclic antidepressants and may be related to its relatively high potency in affecting serotonergic neurotransmission. The drug has many anticholinergic effects, but it is relatively well tolerated by the patients for whom it is effective. A 0.4 percent incidence of seizures, a potentially serious side effect, has been observed. Other antidepressants that are relatively selective for serotonergic (as opposed to noradrenergic) transmission may be as effective as clomipramine in the treatment of this disorder; controlled studies are under way. Clomipramine at low doses is also effective in the treatment of panic disorder and has been used successfully in the treatment of premature ejaculation.

Clinical Trials as Topic↗
PubMed1990

Bupropion: new therapy for depression.

Bupropion is one of the most recently approved antidepressant drugs. The drug differs in chemical structure from the tricyclic antidepressants. It mechanism of action is unknown. Bupropion weakly blocks dopamine uptake, but this property does not seem to account for the antidepressant effects. In clinical trials, bupropion has shown satisfactory antidepressant action compared with placebo. Because long-term effects are not well established, bupropion should be discontinued after several months of therapy.

Antidepressive Agents↗
PubMed1988

Stable expression of the tax gene of type I human T-cell leukemia virus in human T cells activates specific cellular genes involved in growth.

Stable expression of the 40-kDa transactivator protein (Tax) from the type I human T-cell leukemia virus (HTLV-I) in Jurkat T cells leads to the activation and sustained expression of certain cellular genes that are transiently induced during normal T-cell growth. Cellular genes induced by Tax include those encoding the alpha subunit of the high-affinity interleukin 2 receptor (Tac), interleukin 2, and granulocyte/macrophage colony-stimulating factor. Tax induction of the interleukin 2 gene is synergistically amplified by mitogens that augment cytoplasmic levels of calcium. These changes in the pattern of cellular gene expression reflect a specific action of Tax, as they are undetectable in isogenically matched control cell lines expressing antisense tax cDNA. The spectrum of cellular genes regulated by Tax appears to be restricted: several other T-cell genes, either inducibly or constitutively expressed, are unaffected by this viral protein. These cell lines constitutively expressing Tax provide valuable reagents to explore the molecular basis for Tax action and to delineate the full spectrum of cellular genes regulated by this retroviral gene product.

Animals↗
PubMed1986

Facial electromyography in depression. Subgroup differences.

To study whether facial electromyographic (EMG) activity during affective imagery differed between normal subjects and depressive subtypes, we evaluated EMG responses in 29 normal controls, 37 endogenously depressed patients, and 26 nonendogenously depressed patients. Different imagery states produced more distinctive EMG patterns in normal controls than in depressed patients. Patients with endogenous depression had EMG levels that differentiated them from normal subjects and had significantly greater absolute values than the nonendogenous group in corrugator happy and corrugator sad imagery trials. Intensity of sad and happy imagery, age, and severity of depression did not systematically correlate with EMG activity among depressive subtypes.

Adult↗
PubMed1986

Simultaneous panic and depressive disorders: clinical and sleep EEG correlates.

Panic and depressive symptoms occur simultaneously in many depressed patients. To study the frequency of this association and to determine whether patients with simultaneous panic and major depression differed from those with only major depressive disorder (MDD) in clinical features and in sleep electroencephalographic (EEG) variables, we evaluated a total sample of 336 patients with MDD. Fifty-eight (17%) had both panic and MDD; 50 had complete data and were matched for age and severity of illness with other patients having only MDD. Patients with simultaneous panic and depression had significantly higher ratings for psychic and somatic anxiety, and rapid eye movement (REM) latencies approximating normal values. Patients with only MDD (without panic disorder) rated significantly higher in guilt feelings and had shorter REM latencies. Our results suggest that the simultaneous occurrence of panic and depression is relatively frequent, is accompanied by differences in sleep EEG variables, and may have implications for treatment.

Adult↗