Search PubMed⌕ Search

Biomedical subjects

D J Cohen

Publications and source records attributed to D J Cohen.

At least 19 recordsLinked to original sources
PubMed1992

Predictors of long-term outcome after percutaneous balloon mitral valvuloplasty.

BACKGROUND: Percutaneous balloon mitral valvuloplasty is known to produce short-term hemodynamic and symptomatic improvement in many patients with mitral stenosis. Comprehensive assessment of the clinical usefulness of balloon valvuloplasty requires evaluation of patients' long-term outcomes. METHODS: We performed balloon mitral valvuloplasty in 146 patients between October 1, 1985, and October 1, 1991. Base-line demographic, clinical, echocardiographic, and hemodynamic variables were evaluated in order to identify predictors of long-term event-free survival. RESULTS: Balloon mitral valvuloplasty was completed successfully in 136 (93 percent) of the patients in whom the procedure was attempted; it resulted in an increase in the mean (+/- SD) mitral-valve area from 1.0 +/- 0.4 to 2.1 +/- 0.9 cm2 and a decrease in the mean transmitral pressure gradient from 14 +/- 5 to 6 +/- 3 mm Hg (P < 0.001 for both comparisons). The estimated overall five-year survival rate was 76 +/- 5 percent, and the estimated five-year event-free survival rate (the percentage of patients without mitral-valve replacement, repeat valvuloplasty, or death from cardiac causes) was 51 +/- 6 percent. According to multivariate Cox proportional-hazards analysis, the independent predictors of longer event-free survival were a lower mitral-valve echocardiographic score (a measure of mitral-valve deformity; range, 0 for a normal valve to 16 for a seriously deformed valve; P < 0.001), lower left ventricular end-diastolic pressure (P = 0.001), and a lower New York Heart Association (NYHA) functional class (P = 0.04). Patients with no risk factors for early restenosis or only one risk factor (echocardiographic score > 8, left ventricular end-diastolic pressure > 10 mm Hg, or NYHA functional class IV) had a predicted five-year event-free survival rate of 60 to 84 percent, whereas patients with two or three risk factors had a predicted five-year event-free survival rate of only 13 to 41 percent. CONCLUSIONS: Balloon mitral valvuloplasty as a treatment for selected patients with mitral stenosis has good long-term results. The long-term outcome after this procedure can be predicted on the basis of patients' base-line characteristics.

Catheterization↗
PubMed1992

Three diagnostic systems for autism: DSM-III, DSM-III-R, and ICD-10.

ICD-10 draft research criteria for childhood autism were applied to a previously published data set comparing DSM-III and DSM-III-R to clinicians' diagnoses of autism. The ICD-10 approach paralleled clinicians' patterns of diagnosis and, to a lesser extent, the DSM-III system. Relative to either clinicians, DSM-III, or ICD-10 the DSM-III-R system overdiagnosed the presence of autism. Implications for research and for future revision of diagnostic criteria are discussed.

Adolescent↗
PubMed1992

Postural control in children with autism.

Postural control was evaluated in samples of autistic, normal, and mentally retarded children in this pilot study using a recently developed, computerized posturographic procedure. A battery of postural positions was administered including postures involving some degree of "stress" (e.g., occluded vision or standing on pads). The postural patterns of children with autism differed from those observed in normal children, in mentally retarded children, and in adults with vestibular disorders. In comparison to normal children the autistic subjects were less likely to exhibit age-related changes in postural performance and postures were more variable and less stable with more lateral sway. Autistic subjects also exhibited a "paradoxical" response of greater stability with more "stressful" postures, putting excessive weight on one foot, one toe, or one heel. The implications for neuroanatomical models of autism are discussed.

Autistic Disorder↗
PubMed1992

Systolic anterior motion of the chordal apparatus after mitral ring insertion.

To describe the Doppler and two-dimensional echocardiographic characteristics of systolic anterior motion of the chordal apparatus after mitral annuloplasty, 24 consecutive patients (19 men and 5 women; mean age, 55 years) were studied with the use of serial Doppler and two-dimensional echocardiography, which included preoperative transthoracic, intraoperative epicardial, and postoperative transthoracic examinations at 1 week after annuloplasty and every 3 months thereafter for up to 12 months. Systolic anterior leaflet motion of the mitral valve was not seen in this series; however, chordal systolic anterior motion was seen in three patients during surgery and in one additional patient at the time of the 1-week transthoracic examination. During subsequent studies at 3-month intervals, chordal systolic anterior motion was not present. The left ventricular outflow tract velocities were normal in all patients with and without chordal systolic anterior motion. In conclusion, chordal systolic anterior motion should be differentiated from leaflet systolic anterior motion after mitral annuloplasty because the former is a transient, benign, and relatively common finding.

Adult↗
PubMed1992

Mammalian sperm-egg fusion: the rat egg has complementary sites for a sperm protein that mediates gamete fusion.

Rat epididymal protein DE is localized on the fusogenic region of the acrosome-reacted spermatozoa and has a potential role in sperm-egg fusion. We investigated the presence of DE binding sites on the egg surface by co-incubating zona-free eggs and capacitated sperm in different concentrations of pure DE. Results indicate that DE produced a concentration-dependent decrease in egg penetration by sperm (fusion), with almost complete inhibition at 200 micrograms/ml. This inhibition was not due to an effect of DE on initial sperm binding to the egg membrane, since the presence of this protein did not affect the percentage of oocytes with bound sperm nor the number of bound sperm per egg. Those sperm that failed to penetrate the egg in the presence of DE became able to do so after transfer of the eggs to protein- and sperm-free medium, indicating a role for DE in an event subsequent to binding and leading to fusion. Indirect immunofluorescence using a polyclonal antibody against DE revealed a patchy labeling over the entire egg surface, with the exception of the area overlying the second metaphase spindle. This conclusion was supported by the disappearance of the DE-negative area on the fertilized egg. Zona-free eggs, incubated with DE at 4 degrees C or fixed before exposure to DE, displayed a uniform staining, suggesting that the patchy labeling resulted from aggregation of DE binding sites by the purified protein. The aggregation of these egg components may represent a necessary step of the fusion process. To our knowledge, this is the first study reporting the existence and localization of complementary sites to a specific sperm protein on the plasma membrane of the mammalian egg.

Amino Acid Sequence↗
PubMed1992

Cyclosporine: nephrotoxic effects and guidelines for safe use in patients with rheumatoid arthritis.

Renal abnormalities occur frequently in patients with rheumatoid arthritis; they may be complications of the rheumatoid disease process itself (amyloidosis) or may result from various therapies including gold compounds, D-penicillamine, analgesics such as aspirin or phenacetin used long term, and nonsteroidal anti-inflammatory drugs. Cyclosporine, a highly effective immunosuppressive agent currently under investigation as a treatment for RA, is also known to produce renal dysfunction. Some forms of functional and structural tubular changes appear readily reversible. Others associated with renal vasculopathy and interstitial fibrosis can lead to irreversible nephrotoxicity. A clear understanding of the pharmacology, drug interactions, and types of renal side effects encountered with cyclosporine can lead to a reduction of adverse renal reactions. Similarly, an understanding of which patients are at high risk for renal dysfunction can lead to safer and more efficacious use of this potent immunosuppressive agent.

Arthritis, Rheumatoid↗
PubMed1992

Steroid hormones and CNS sexual dimorphisms modulate symptom expression in Tourette's syndrome.

We present our hypothesis that various steroid hormones play an important role in the symptom expression of Gilles de la Tourette's syndrome (TS) and that androgenic hormones, in particular, are likely to exacerbate symptoms of the disorder. We review the clinical evidence supporting our hypothesis. Sex steroids establish brain sexual dimorphisms early in CNS development, and we suggest mechanisms whereby androgenic and other hormonal changes later in human development might act at dimorphic brain regions to influence the natural history of TS. Finally, we discuss the various ways in which neuroendocrine studies might assist in genetic and neurobiologic research programs in TS.

Adolescent↗
PubMed1992

Platelet dense granule release reaction monitored by high-performance liquid chromatography-fluorometric determination of endogenous serotonin.

The platelet dense granule release reaction was monitored by measuring the serotonin content of platelets collected by filtration following release. Sensitive HPLC-fluorometric analysis permitted release to be assessed using small (25-50 microliters) volumes of plasma and whole blood. Release could be examined for periods as short as 1 s due to the rapid stoppage effected by filtration. The half-life of thrombin-stimulated (1 U/ml) release was 2-3 s, the EC50 values observed for thrombin-stimulated release over a 60-s release period were 0.01-0.03 U/ml for diluted whole blood and plasma samples.

Blood Platelets↗
PubMed1992

The development of a capacity for imagination in early childhood.

Imagination as a mental capacity is part of a line of development that begins in the earliest symbiotic interactions between mother and infant, takes further shape as the child moves from dyadic to triadic relations, and culminates in a fully mature capacity to reflect upon in thought one's wishes and feelings vis-à-vis multiple others. Particularly for the 3- to 5-year-old child, imagination represents a special mode of mental functioning which allows him to expand his internal object world, motivates him toward increasingly complex relationships with others, and is a central precondition for the creation of the self-defining fantasies characteristic of the oedipal phase. The central neurocognitive precondition for an imaginative capacity is the ability to distinguish thought from action and understand that others as well as oneself are motivated to act because of mental states such as feelings, beliefs, and fantasies. In this paper, we present a view of imagination that integrates observations from psychoanalytically informed studies of the emergence of fantasy play in the oedipal phase with findings from recent work on how children acquire an understanding of their own and others' mental processes.

Child↗
PubMed1992

Behavioral treatment of children and adolescents with trichotillomania.

Trichotillomania is a behavior disorder with onset generally in childhood, characterized by repetitive, compulsive pulling out of hair from the scalp, eyebrows, or other parts of the body, often leading to disfigurement. Trichotillomania tends to be persistent and is often resistant to counselling and standard psychiatric care. A systematic behavioral treatment program for children and adolescents and pilot findings with three patients are described. Methodological issues in relation to compliance and assessment are discussed. The relative safety and potential effectiveness of behavioral techniques suggest a useful role for this approach, perhaps in conjunction with pharmacological, family, and other treatment modalities.

Adolescent↗
PubMed1992

Clomipramine in autism: preliminary evidence of efficacy.

This report provides preliminary evidence for the efficacy of clomipramine in the treatment of young adults with autistic disorder. Four of five outpatients with autistic disorder showed significant improvement in social relatedness, obsessive compulsive symptoms, and aggressive and impulsive behavior with clomipramine treatment. These findings are consistent with previous evidence, suggesting that serotonin neurotransmission may be relevant to the treatment, and possibly the pathophysiology, of some symptoms of autistic disorder.

Adolescent↗
PubMed1992

An epidemiological study of obsessive-compulsive disorder and related disorders in Israeli adolescents.

Five hundred and sixty-two, 16- to 17-year-old consecutive inductees into the Israeli Army, constituting a random sample of their cohort, were screened for obsessive-compulsive disorder (OCD), Tourette's syndrome, transient tics (TT), chronic multiple tics (CMT), and attention-deficit hyperactive disorder (ADHD). Two child psychiatrists interviewed the subjects, using screening items from structured interviews that implement DSM-III-R diagnostic criteria. For OCD, a point prevalence of 3.6% was found, 3.9% for ADHD, 1.8% for CMT, and 1.6% for TT. For ADHD, TT, and CMT, but not for OCD, there was a significantly higher prevalence for males than for females. Among the OCD individuals, there was an elevation of TT, CMT, and Tourette's syndrome relative to the population rates.

Adolescent↗
PubMed1992

Double-blind, crossover trial of fluoxetine and placebo in children and adolescents with obsessive-compulsive disorder.

Rigorously designed clinical trials have demonstrated the efficacy and safety of fluoxetine in adults with major depressive disorder and obsessive-compulsive disorder (OCD) but not in patients below 18 years old. This report describes a randomized, double-blind, placebo-controlled, fixed-dose (20 mg qd) trial of fluoxetine in 14 children and adolescents with OCD, ages 8 to 15 years old; the study was 20 weeks long with crossover at 8 weeks. Obsessive-compulsive symptom severity was measured on the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) and the Clinician's Global Impression-Obsessive Compulsive Disorder scale (CGI-OCD). The CY-BOCS total score decreased 44% (N = 7, p = .003) after the initial 8 weeks of fluoxetine treatment, compared with a 27% decrease (N = 6, p = .13) after placebo. During the initial 8 weeks, the magnitude of improvement for the fluoxetine group significantly exceeded that for the placebo group as measured by the CGI-OCD (p = .01) but not by the CY-BOCS (p = .17). The most common drug side effects were generally well tolerated. The results suggest that fluoxetine is a generally safe and effective short-term treatment for children with OCD.

Adolescent↗
PubMed1992

Effect of synchronous and asynchronous pulsatile flow during left, right, and biventricular bypass.

Ventricular assist devices augment flow from the left atrium to the aorta and/or from the right atrium to the pulmonary artery. Most devices are used in the asynchronous full-to-empty mode (asynchronous) but may also be used in a synchronous counterpulsation mode (synchronous). This study determines the optimal assist modes to reduce myocardial oxygen consumption (MVO2) and metabolism. Twelve pigs were instrumented with carotid artery and Baim coronary sinus catheters for determination of MVO2 and myocardial lactate production (LACT). Six were implanted with a Pierce-Donachy left ventricular assist device (LVAD) and 6 with both right and left ventricular assist devices (BIVAD). Two periods each of control, synchronous, and asynchronous bypass were instituted, the midanterior descending coronary artery (LAD) was ligated, and the sequence was repeated. After each period, MVO2 and LACT were determined and myocardial biopsy specimens were obtained for tissue, lactate, and ATP assay. Following LAD ligation, biopsy specimens were obtained from both the infarct and noninfarct zones of the heart. MVO2 decreased (p < 0.05) in the asynchronous BIVAD mode compared with control. MVO2 was unchanged in synchronous BIVAD or either LVAD mode. Tissue ATP and tissue lactate were unaffected by any mode of bypass. Only BIVAD in the asynchronous mode reduced MVO2. When ventricular assist devices are utilized to aid recovery of the natural heart, two devices should always be inserted to allow biventricular assist. Synchronous counterpulsation offers no advantage.

Adenosine Triphosphate↗