Biomedical subjects

J Feldman

Publications and source records attributed to J Feldman.

At least 55 records · Page 3Linked to original sources

PubMed1999

Participation of imidazoline receptors and alpha(2-)-adrenoceptors in the central hypotensive effects of imidazoline-like drugs.

The central hypotensive effect of imidazoline-like drugs (IMs) involves non-adrenergic imidazoline receptors (IRs). IMs cause hypotension irrespective of their affinity and selectivity for one or the other alpha-adrenoceptor subtypes. LNP 509, which binds to I1Rs (Ki = 5.10(-7) M) but roughly not to alpha 2-adrenoceptors (A2Rs) (Ki > 10(-5) M), causes hypotension when injected alone into the brainstem. As far as hybrid drugs, that is, those with mixed binding profiles (I1/alpha 2), are concerned, a significant correlation was reported between their central hypotensive effect and their affinity for IRs. Imidazoline antagonists such as idazoxan competitively antagonized the centrally induced hypotensive effect of IMs. Yohimbine, an A2Rs antagonist, blocks the hypotensive effect of hybrids but usually in a noncompetitive manner. Mutation of A2Rs prevented the hypotensive effects of drugs highly selective for A2Rs, but also that of hybrids such as clonidine. These data indicate that triggering of the hypotensive effects of IMs (1) needs implication of IRs; (2) appears to be facilitated by additional activation of A2Rs; and (3) requires integrity of A2Rs along the sympathetic pathways.

Animals↗

PubMed1999

[Comprehensive geriatric assessment--its clinical, social and economic importance and prospects].

It is well known that many elderly patients are referred to nursing homes because of "functional decline" without being thoroughly investigated. We studied 9 elderly patients, all referred to hospital due to functional decline and diagnosed as follows: spinal stenosis--2 cases, depression--3, thyrotoxicosis--1, Parkinson--1, polypharmacy and congestive heart failure--1 patient each. Proper diagnosis and appropriate treatment prevent unnecessary hospitalization in nursing homes. Our study is meant to draw attention to this crucial aspect of geriatric medicine.

Activities of Daily Living↗

PubMed1999

Incidence and risk factors for heterosexually acquired HIV in an inner-city cohort of women: temporal association with pregnancy.

BACKGROUND: A growing proportion of AIDS cases in the United States are due to heterosexual transmission of HIV, particularly in women. The risk of heterosexually acquired HIV was prospectively studied in a cohort of inner-city women with no history of parenteral drug use. METHODS: Study participants were evaluated at 6-month intervals for the presence of HIV antibody, sexually transmitted diseases, self-reported sexual behavior, and drug use by self-report and urine screening. RESULTS: Of 449 initially HIV-negative women who were seen at least once in follow-up, 4 seroconverted to HIV, with a cumulative incidence of 2.4% at 30 months. Risk factors for HIV seroconversion included nonparenteral drug use (p < .02) and anal intercourse (p < .01). Sexually transmitted diseases were not associated with HIV, although the power to detect such an association was limited. In addition, 3 of 4 seroconverters became pregnant, yielding a rate of 55.5 pregnancies/100 person-years of follow-up compared with a rate of 11.1 pregnancies/100 person-years of follow-up in nonseroconverters (p < .03). CONCLUSION: The incident rate of heterosexually acquired HIV in this inner-city U.S. cohort of women who were not using parenteral drugs is comparable with that reported in some developing countries where heterosexually acquired HIV is endemic. Most seroconversions appeared related to risk behavior seen in association with nonparenteral drug use. The previously unreported association of incident HIV infection with pregnancy in this cohort may be related to either behavioral or biologic factors.

Adult↗

PubMed1999

Are Actions Regretted More Than Inactions?

Several researchers have claimed that negative outcomes produce greater regret when they result from actions rather than from failures to act (Gleicher et al., 1990; Kahneman & Tversky, 1982; Landman, 1987). We investigated this claim by asking participants to write descriptions of strongly regretted events in their own lives and to rate the intensity of the regrets. Participants reported more inaction than action regrets, and, contrary to prior research findings, regrets produced by actions and inactions were equally intense. We conjecture that many factors that affect the content of real-life regrets are eliminated in studies of hypothetical regret. In real life, actions and inactions do not generally produce the same outcomes. Furthermore, actions and inactions may differ in how easily one can anticipate the potential for harm. Specifically, it is plausible that people control their actions to avoid potential regrets, leaving themselves vulnerable to regrets from inactions. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

The role of objects in perceptual grouping.

Perceptual organization can be viewed as the selection of the best or "most reasonable" parse of a given scene. However, the principles that determine which interpretation is most reasonable have resisted most attempts to define them formally. This paper summarizes a formal theory of human perceptual organization, called minimal model theory, in which the best interpretation of a given scene is expressed as the formally minimal interpretation in a well-defined space of possible interpretations. We then focus specifically on the role of types of grouping units, in particular the difficult notion of "object". Although grouping is often thought of as the process of dividing the image into objects, most research in perceptual grouping actually focuses on simpler types of units, such as contours and surfaces. Minimal model theory characterizes grouping units at a logical level, demonstrating how formal assumptions about units induce the observer to place a certain preference ranking on interpretations. The theory is then applied to the more subtle problem of objects, culminating in a definition for objects that is formally rigorous but at the same time captures some of the flexibility of human intuitions about objects.

Attention↗

PubMed1999

Prevalence and incidence of gynecologic disorders among women infected with human immunodeficiency virus.

OBJECTIVE: Our purpose was to ascertain the prevalence, incidence, and predictors of gynecologic disorders among women infected with human immunodeficiency virus. STUDY DESIGN: We serially assessed 292 women infected with human immunodeficiency virus and 681 uninfected women. Outcomes were incidence and prevalence of sexually transmitted diseases, viral shedding, findings of Papanicolaou smears, fungal infections, and menstrual disorders. RESULTS: Women infected with the virus were more likely to have prevalent vulvovaginal candidiasis (odds ratio 1.80, 95% confidence interval 1. 0-3.25, P =.05), oncogenic human papillomavirus (odds ratio 3.79, 95% confidence interval 2.43-5.91, P =.001), abnormal Papanicolaou smears (odds ratio 5.40, 95% confidence interval 3.35-8.78, P =.001), amenorrhea (4.8% vs 0%, P =.05), positive results on Treponema pallidum hemagglutination assay (odds ratio 1.83, 95% confidence interval 1.16-2.88, P =.01), infection with cytomegalovirus (odds ratio 4.2, 95% confidence interval 1.82-10.62, P =.001), and genital warts (odds ratio 6.93, 95% confidence interval 3.16-16.30, P =.001) but were less likely to have Chlamydia trachomatis infection (odds ratio 0.28, 95% confidence interval 0.10-0.66, P =.01). Annual incidence rates among women infected with human immunodeficiency virus were 4.0% for candidiasis, 22.0% for oncogenic human papillomavirus, 11.4% for genital warts, 1.7% for infection with C trachomatis, 1.7% for infection with Neisseria gonorrhoeae, 10.3% for Trichomonas vaginalis, 1.1% for positive results on T pallidum hemagglutination assay, 7.4% for an abnormal Papanicolaou smear, and 10.9% for infection with herpes simplex virus. Overall, 46.9% had at least 1 incident condition. Women infected with human immunodeficiency virus were more likely to have incident oncogenic human papillomavirus infection (odds ratio 2.0, 95% confidence interval 1.01-3.8), abnormal Papanicolaou smears (odds ratio 7.76, 95% confidence interval 2.08-42.8), and genital warts (odds ratio 9. 32, 95% confidence interval 3.04-38.0). Incidence and prevalence of sexually transmitted diseases and oncogenic human papillomavirus infection increased with increased CD4(+) cell counts. CONCLUSIONS: Women infected with the human immunodeficiency virus are significantly more likely to have prevalent and incident gynecologic disorders but not disorders related to risk taking (eg, incident sexually transmitted diseases). The latter disorders increased in women with CD4(+) cell counts >500 cells/mm3. Clinicians should be aware of these patterns so that they can provide appropriate evaluation and treatment of gynecologic disorders.

Adult↗

PubMed1999

The clinical efficacy of paremyd with and without dapiprazole in subjects with light and dark brown irides.

BACKGROUND: Paremyd, a mydriatic formulation of 0.25% tropicamide and 1.0% hydroxyamphetamine hydrobromide provides adequate dilation for binocular indirect ophthalmoscopy in young Caucasians. We studied the clinical effectiveness of Paremyd in dilating heavily pigmented eyes by comparing its mydriatic efficacy in Blacks, Asians and Caucasians with light and dark brown irides. We also evaluated the efficacy of one drop of dapiprazole (Rev-Eyes) in reversing Paremyd-induced mydriasis in our subject sample. METHODS: In a masked, randomized, controlled experimental design, several visual functions which included pupillary dilation, near visual acuity, amplitude of accommodation, ocular hyperemia, and discomfort glare were measured at 30-min intervals, for a total of 300 min, in subjects dilated with a single drop of Paremyd in each eye. Ease of binocular indirect ophthalmoscopy was also assessed. A 3-way analysis of variance was used to assess changes in these measures as function of irides color/pigmentation (designated as light or dark brown iris color), presence or absence of dapiprazole, and test time interval. RESULTS: We found that subjects in our light brown irides group (mainly Caucasians) dilated faster than subjects in our dark brown irides group (mainly Blacks). Dapiprazole increased the speed of recovery from pupillary dilation for all subjects, but more so for those with light rather than dark brown irides. Similarly, subjects with light rather than dark brown irides recovered accommodative function more quickly. Although neither the use of dapiprazole nor the degree of iris color/pigmentation was significantly related to visual acuity or glare discomfort, there was a clear trend that these visual measures were affected to a greater degree in subjects with dark brown (primarily Blacks) rather than light brown irides. Overall, Paremyd provided adequate dilation for binocular indirect ophthalmoscopy in all subjects irrespective of iris color/pigmentation. CONCLUSIONS: Our data indicate that a single drop of Paremyd provides adequate mydriasis, without significant side effects, for routine fundus examination of all subjects, independent of iris color/pigmentation. Furthermore, a single drop of dapiprazole was effective in speeding the return of pupillary dilation in most subjects, but had no significant effect on accommodation, near visual acuity or glare discomfort. Side effects such as stinging upon instillation, conjunctival hyperemia, and a few instances of ptosis, with possible additional cost to patients, appear to lessen its overall clinical benefit.

Accommodation, Ocular↗

PubMed1999

Creatine kinase MB isoenzyme of noncardiac origin in elderly patients.

Increased activity of creatine kinase MB (CKMB) isoenzyme is regarded as highly diagnostic for acute myocardial infarction. We report two cases of elderly patients with increased levels of CKMB but no evidence of cardiac injury. We conclude that numerous factors influence CKMB activity and that the suitability of this test for the diagnosis of cardiac muscle damage in the elderly should be viewed with caution.

Aged↗

PubMed1999

Cardiovascular effects of clonidine-like drugs in pithed rabbits.

Administration (3 to 100 microg/kg IV) of clonidine, rilmenidine, and an imidazoline derivative, 2-(2-chlorophenylamino)imidazoline, in pithed nonstimulated rabbits caused a dose-dependent increase in mean arterial pressure without affecting heart rate. Prazosin (0.1 mg/kg IV) almost abolished the pressor responses to 2-(2-chlorophenylamino)imidazoline, partially inhibited those induced by clonidine, but failed to affect those elicited by rilmenidine. In contrast, yohimbine (1 mg/kg IV) blunted the pressor responses of the 3 drugs. In sympathetically stimulated pithed rabbits, 2-(2-chlorophenylamino)imidazoline induced only pressor effects, whereas clonidine and rilmenidine caused a transient pressure increase followed by a dose-dependent depressor effect. Yohimbine abolished the depressor effect of both drugs, which may have involved presynaptic alpha(2)-adrenoceptors. In conclusion, peripheral effects of 2-(2-chlorophenylamino)imidazoline and clonidine involved at least alpha(1)- and alpha(2)-adrenoceptor activation, whereas pressor and depressor effects of rilmenidine were mediated by alpha(2)-adrenoceptors.

Animals↗

PubMed1999

The influence of HIV-related knowledge and exposure fears on behavior change and incident STDs.

Using a sample of 678 HIV-seronegative women, we measured self-reports of HIV-related cognitions, specifically knowledge, perceived exposure risks, and outcome expectations. We also ascertained prevalent and incident bacterial STDs and measured self-reports of behavioral risk reductions. We tested for associations between (a) cognitions and STD prevalence, (b) cognitions and incident STDs, (c) cognitions and behavioral risk reductions, and (d) risk reductions and incident STDs. Symptom knowledge was associated with lower prevalence, but not incidence. Beliefs in the efficacy of risk reductions showed a protective effect against incident STDs. Perceived exposure risk and symptom knowledge were associated with risk reduction behavior.

Adolescent↗

PubMed1999

Occupational choice and patterns of cognitive abilities.

Previous studies by Govier and colleagues have shown dichotic listening performance to be related to occupation. The results of these studies were interpreted as supporting the view that both occupational choice and dichotic listening asymmetries depend upon biologically determined aspects of brain organization. The present study sought to test further the link between occupation and cognition by investigating the patterns of spatial and verbal abilities in males and females in male-dominated occupations and males and females in female-dominated occupations. It was hypothesized that occupational choice would be a salient marker for within-sex variation on cognitive tasks previously shown to differentiate performance in men and women. The results supported the hypothesis, and are interpreted as strengthening the view that occupational choice is, at least in part, a function of an individual's cognitive organization.

Adult↗

PubMed1999

Drugs acting on imidazoline receptors: a review of their pharmacology, their use in blood pressure control and their potential interest in cardioprotection.

Drugs acting within the autonomic nervous system are of particular interest when autonomic abnormalities are implicated in the development and maintenance of various cardiovascular pathologies. For example, it has been documented that in the early stages of hypertensive disease, i.e. hyperkinetic borderline hypertension, a sympathetic hyperactivity associated with a decreased parasympathetic activity results in increased cardiac output and heart rate. Several classes of drugs acting within the central, as well as the peripheral, autonomic nervous system are very efficient in treating hypertensive disease. One class - the second generation of a group of centrally acting drugs selective for imidazoline receptors - has proved beneficial in this respect, because drugs in this class are well tolerated and have interesting additional effects such as their antiarrhythmic action. Rilmenidine and moxonidine are the lead compounds of this class of drugs. Rilmenidine and moxonidine both proved more selective for cerebral imidazoline receptors than the reference drug, clonidine. It was suggested that this selectivity, attributable to their lower affinity for alpha2-adrenoceptors, explains the low incidence of adverse effects (including sedation) associated with these drugs. In addition, potentially beneficial actions on cardiac dysrythmias and congestive heart failure enlarge the therapeutic potential of the second generation of imidazoline-related drugs. This review focuses on the main pharmacological and clinical properties of rilmenidine and moxonidine, paying particular attention not only to their efficacy in hypertension but also to other potential cardiovascular indications.

Animals↗

PubMed1999

Effects of ifenprodil and baclofen on exercise-induced increase of myocardial oxygen demand in normotensive rats.

Central glutamatergic relays are known to be present in the central sympathetic pathways. Ifenprodil (an N-methyl-D-aspartate antagonist) and baclofen (a gamma-aminobutyric acid(B) agonist) are both modulators of these synapses; we previously reported their ability to reduce the cardiovascular responses induced by a central hypothalamic stimulation in rabbits. In this work, we investigated the actions of chronic treatments with these two drugs on the increase of myocardial oxygen demand induced by exercise in normotensive rats. Moreover, their effects on the baroreceptor heart rate reflex were observed. Male normotensive WKY rats were treated with placebo (two groups), baclofen, or ifenprodil for 14 days. They were then submitted to a progressively increased exercise test on a treadmill. In another three groups of animals, the same treatment was applied but, at the end, a baroreflex study was performed by the injection of phenylephrine (vagal component of the reflex) and of sodium nitroprusside (sympathetic component). Ifenprodil and baclofen reduced by nearly 50% the level of the increase of the rate x pressure product during exercise as compared with control rats. This effect appeared to be mainly due to a reduction of the hypertensive response. In the same conditions, neither baclofen nor ifenprodil significantly altered the baroreceptor heart rate reflex. The fact that these two drugs are capable of reducing the myocardial oxygen demand encourages us to test them in a model of myocardial ischemia associated with sympathetic hyperactivity.

Animals↗

PubMed1999

Differences in morbidity measures and risk factor identification using multiple data sources: the case of stroke.

BACKGROUND: Epidemiologic studies utilise medical information from a variety of sources. These include subject or proxy interviews, medical records, death certificates and administrative records. Since the choice of data source may affect the validity of study results, it is important to understand the effect of different case-ascertainment methodologies on estimates of risk. METHODS: The NHANES I Epidemiologic Follow-up Study (NHEFS) contains several sources of information that can be used to define case status. In this report we investigate whether the use of seven different algorithms for case ascertainment, each based on different combinations of data sources, results in substantive differences in the estimates of incidence rates and relative risks associated with selected, documented, risk factors for stroke. RESULTS: The seven different models of case identification gave very different estimates of stroke incidence. However, the characteristics of the cases defined by the models, except for cases identified by death certificate only, were remarkably similar. There was also remarkable similarity in relative risks obtained from six of the seven models. The model using only death certificate information generally produced higher relative risk estimates. CONCLUSIONS: Despite wide variations in the estimates of incidence, characteristics of the cases using different case definition were remarkably similar, as were the risks associated with stroke incidence. The main difference occurred when cases were identified from the death certificate only. These results furnish some evidence that analyses based on self report can provide valid, useful information.

Adult↗

PubMed1999

Treatment adherence among Latina female adolescent suicide attempters.

Clinicians must identify factors among suicide-attempting adolescents and their families that increase treatment adherence. Researchers assessed a consecutive series of 140 disenfranchised Latina adolescents (ages 12-18 years) and their mothers presenting at a large urban emergency room after a suicide attempt by the adolescent. Adherence was examined as it related to service delivery, individual background characteristics, and psychosocial factors (current symptomatology, treatment attitudes). Each factor was found to predict adolescent treatment adherence. Adolescents receiving a specialized emergency room program, those with a diagnosis of disruptive behavior disorder, and those from single-parent households attended significantly more therapy sessions compared to their suicide-attempting peers receiving standard emergency room care. Adolescents with a diagnosis of anxiety disorders and those whose mothers reported more psychopathology and perceived more cohesive family relationships tended to attend significantly fewer treatment sessions. The implications for the delivery of emergency room interventions are discussed.

Adolescent↗

PubMed1999

[Infective endocarditis presenting as polyarticular septic arthritis].

We report acute polyarthritis in an 86-year-old man which was initially considered to be an exacerbation of osteoarthritis. After a delay of a few days a diagnosis of septic polyarthritis as an initial symptom of infective endocarditis was made. Although rheumatic manifestations in infective endocarditis are common, septic polyarthritis is rarely seen. In our patient the course of the disease was rapidly fatal.

Acute Disease↗

PubMed1998

Does a second generation of centrally acting antihypertensive drugs really exist?

The site of the hypotensive action of imidazoline compounds, such as clonidine, was first identified within the rostroventrolateral part of the brainstem: the nucleus reticularis lateralis. After that, it was shown that imidazolines and related substances reduced blood pressure when applied in this area whereas catecholamines were not capable of producing such an effect. These data led us to suggest the existence of receptors specific for imidazoline-like compounds different from the alpha2-adrenoceptors. Soon after, the existence of imidazoline binding sites was reported in the brain and in a variety of peripheral tissues including the human kidney. As expected, these specific binding sites do not bind the catecholamines. The imidazoline binding sites are already subclassified in two groups: the I1-subtype sensitive to clonidine and idazoxan, and the I2-subtype, sensitive to idazoxan and nearly insensitive to clonidine. Functional studies confirmed that the hypotensive effects of clonidine-like drugs involved imidazoline receptors while their most frequent side effects only involved alpha2-adrenoceptors. However, recent functional evidence suggests that a cross talk between imidazoline receptors and alpha2-adrenoceptors is necessary to trigger a hypotensive effect within the ventral brainstem. Rilmenidine and Moxonidine are the leader compounds of a new class of antihypertensive drugs selective for imidazoline receptors. At hypotensive doses, these drugs are devoid of significant sedative effect. Rilmenidine evoked hypotension when injected within the nucleus reticularis lateralis region; it competed for [3H]-clonidine bound to specific imidazoline binding sites in human medullary membrane preparations but proved more selective for cerebral imidazoline receptors than clonidine. It is suggested that this selectivity might explain the low incidence of their side effects. Additional potentially beneficial actions on cardiac arrhythmias or congestive heart failure enlarge the therapeutic interest of imidazoline-related drugs. Recent binding and functional data throw a new light on the optimal pharmacological profile of this second generation of centrally acting antihypertensive drugs.

Animals↗

PubMed1998

[Community-acquired pneumonia in the elderly--guidelines for hospitalization].

A prospective study was carried out among elderly patients with community-acquired pneumonia to determine if there are any specific features that could help in deciding whether to hospitalize, or to treat in the community. We concluded that there is no correlation between clinical presentation of pneumonia and outcome, except for impairment of consciousness. Laboratory data showed a correlation between oxygen saturation in arterial blood, levels of hemoglobin and albumin, and outcome. Sputum culture was not helpful in deciding about diagnosis and treatment, which remain empiric. These patients should be treated at home if conditions permit. Recommendations are made for improving such conditions.

Aged↗