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Biomedical subjects

S Zimmerman

Publications and source records attributed to S Zimmerman.

At least 37 records · Page 2Linked to original sources
PubMed1998

Hyperreninemic hypertension secondary to a subcapsular perinephric hematoma in a patient with polyarteritis nodosa.

Page kidney is the name ascribed to a rare syndrome of hyperreninemic hypertension caused by unilateral compressive perinephritis. Blood or fluid that accumulates in the perinephric subcapsular space compresses the renal parenchyma leading to ischemia. This syndrome is analogous to the description of cellophane-induced perinephritis by Page in 1939. Page kidney typically presents in healthy young men after blunt trauma to the flank or abdomen, although cases have been noted after medical or surgical interventions. We report a case of a Page kidney in a young man with hepatitis B virus-associated polyarteritis nodosa. The patient presented with severe hypertension, hypokalemia, hyperreninemia, and radiographic evidence of a unilateral subcapsular hematoma. Perinephric hemorrhage developed because of necrotizing vascular inflammation and spontaneous or traumatic vascular rupture. In patients who present with new-onset hypertension and hypokalemia with a history of trauma or coexisting vasculitis, the presence of a Page kidney should be considered.

Adult↗
PubMed1998

Suppression of delayed and contact hypersensitivity responses in mice have different UV dose responses.

Although acute exposure to UV radiation suppresses the induction of delayed-type (DTH) and contact (CHS) hypersensitivity in mice, it is not clear whether the photobiological mechanism(s) involved in suppressing these closely related immune reactions is the same. A careful examination of the UV dose responses and wavelength dependencies involved in suppressing CHS and DTH may provide important insights into the mechanisms involved. We compared the UV dose-response curves for suppressing four closely related immune reactions, local and systemic suppression of CHS to dinitrofluorobenzene, systemic suppression of DTH to Candida albicans and systemic suppression of DTH to alloantigen using three different UV spectra (FS40 sunlamps, Kodacel-filtered FS40 sunlamps and solar-simulated light). For each immune response studied, the amount of UVB radiation required to induce 50% immune suppression was lowest when FS40 sunlamps were used, highest with solar-simulated light and intermediate when Kodacel-filtered FS40 sunlamps were used, but the differences observed were not statistically significant. The UV dose-response curves for immune suppression differed significantly depending on the assay used, the site of antigenic sensitization and the antigen used. These findings suggest that the mechanisms by which UV radiation induces immune suppression differ for the four immunological reactions studied.

Animals↗
PubMed1997

Effect of altered auditory feedback on people who stutter during scripted telephone conversations.

The effect of altered auditory feedback (AAF) conditions on stuttering during scripted telephone conversations was investigated. Nine adult participants made 15 scripted telephone calls to business in New York City. Alterations in the participants' auditory feedback signal were generated by a commercially available digital signal processor (Casa Futura Technologies Desktop Fluency System Model BTD-400) that shifted participants' speech one-half octave down in frequency, produced a 50-ms delay, or produced non-altered auditory feedback. The AAF effects produced by the digital signal processor were not perceived by the recipients of the telephone calls. The proportion of stuttering events per scripted telephone conversations were significantly reduced in the AAF conditions relative to the non-altered auditory feedback condition (p = .0004). Stuttering frequency was reduced by 55% and 60% for the FAF and DAF, respectively. These findings demonstrate the applicability of this technology to situations of daily living involving telephone use.

Adult↗
PubMed1996

Cannabinoid enantiomer action on the cytoarchitecture.

The negative and positive enantiomers of 7-hydroxy-delta 6-tetrahydrocannabinol-dimethylheptyl (designated HU-210 and HU-211 respectively) differentially affect undifferentiated and differentiating cultured pheochromocytoma cells (PC-12 cells). In general, cell viability and cell proliferation were suppressed to a much greater extent with HU-210 than with HU-211 in differentiating cells. The effects of these synthetic cannabinoids on the cytoskeleton of PC-12 cells were examined by epifluorescence and confocal microscopy. In both undifferentiated and differentiating PC-12 cells, HU-211 has little effect on the cytoarchitecture whereas HU-210 disrupts the distribution of microtubules and microfilaments. Vacuoles (2-4 microns) were evident in the cytoplasm of HU-210-treated cells but not in the cytoplasm of HU-211-treated cells or in vehicle controls. Tubulin and actin mRNA levels were reduced to 5 and 40%, respectively (relative to untreated controls) in 10 microns HU-210-treated cells whereas the same concentration of HU-211 reduced tubulin and actin mRNA levels to 90 and 95%, respectively. A comparison of the effects of the paired enantiomers and delta 1-THC on the cellular parameters studied reveals that in differentiating cells the action of delta 1-THC is intermediate between that of HU-210 and HU-211. This study demonstrates that compared to HU-210 and delta 1-THC the positive enantiomer HU-211 has little cellular activity.

Actin Cytoskeleton↗
PubMed1996

Evaluation of a HIV/AIDS education program for adolescents.

The adolescent population has recently been recognized as one of the groups at risk for human immunodeficiency virus (HIV) infection. Statistics are beginning to document the extent of this trend. This study is aimed at determining adolescent sexual behaviors and the efficacy of a medical student-run acquired immune deficiency syndrome (AIDS) education program. Medical students taught 2,169 high school students in the St. Louis area with a pre- and post- intervention questionnaire administered to record levels of HIV/AIDS knowledge and sexual practices. Data revealed that 56.4% of the respondents were sexually active with 70.4% having multiple partners and 61.0% admitting to unprotected sex. These students demonstrated a significant increase in their knowledge about HIV infection after the educational program. The results show that, adolescents are sexually active and more importantly, they are practicing behaviors that put them at risk for HIV/AIDS, a risk which they recognize. Finally, the educational intervention did increase students' knowledge of HIV/AIDS. This may not translate into a change in behaviors, but it is a first step.

Adolescent↗
PubMed1995

The frequency and troublesomeness of symptoms associated with Alzheimer's disease.

An increased understanding of the frequency and troublesomeness of symptoms for family members who are caring for a victim of Alzheimer's disease (AD) would be helpful for nurses in working with these families. This article reports on the changes of these symptoms over time as well as the troublesomeness of these symptoms for 30 families over an 18-month period. A symptom checklist based on George's Patient Illness Symptoms Checklist (George, 1983) was used. Over time the reported symptoms reflected increased mental impairment, which is associated with AD. For some of the symptoms, there was an increase in the symptoms' frequency, but their troublesomeness did not increase. Family caregivers who reported more symptoms for each time period also reported an increase in institutionalization of the AD member.

Aged↗
PubMed1994

Anandamide (arachidonylethanolamide), a brain cannabinoid receptor agonist, reduces sperm fertilizing capacity in sea urchins by inhibiting the acrosome reaction.

Anandamide (arachidonylethanolamide) is an endogenous cannabinoid receptor agonist in mammalian brain. Sea urchin sperm contain a high-affinity cannabinoid receptor similar to the cannabinoid receptor in mammalian brain. (-)-delta 9-Tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in marihuana, reduces the fertilizing capacity of sea urchin sperm by blocking the acrosome reaction that normally is stimulated by a specific ligand in the egg's jelly coat. We now report that anandamide produces effects similar to those previously obtained with THC in Strongylocentrotus purpuratus in reducing sperm fertilizing capacity and inhibiting the egg jelly-stimulated acrosome reaction. Arachidonic acid does not inhibit the acrosome reaction under similar conditions. The adverse effects of anandamide on sperm fertilizing capacity and the acrosome reaction are reversible. The receptivity of unfertilized eggs to sperm and sperm motility are not impaired by anandamide. Under conditions where anandamide completely blocks the egg jelly-stimulated acrosome reaction, it does not inhibit the acrosome reaction artificially initiated by ionomycin, which promotes Ca2+ influx, and nigericin, which activates K+ channels in sperm. These findings provide additional evidence that the cannabinoid receptor in sperm plays a role in blocking the acrosome reaction, indicate that anandamide or a related molecule may be the natural ligand for the cannabinoid receptor in sea urchin sperm, and suggest that binding of anandamide to the cannabinoid receptor modulates stimulus-secretion-coupling in sperm by affecting an event prior to ion channel opening.

Acrosome↗
PubMed1994

Calcium channel antagonists induce direct inhibition of the outward rectifying potassium channel in tobacco protoplasts.

Verapamil, nifedipine and bepridil, three antagonists of L-type calcium channels in animal cells, were shown to induce direct inhibition of outward rectifying potassium current in Nicotiana tabacum cv. Xanthi protoplasts with IC50 of 5 microM, 5 microM and 1 microM, respectively. In the outside-out configuration, verapamil reduced the open probability of the ion channel responsible for the outward rectifying potassium conductance. Verapamil also blocked the outward rectifying potassium conductance in protoplasts from the N. tabacum cv. Bright Yellow cell line. Thus, studies using these molecules to demonstrate the involvement of calcium channels in plant physiological responses should be regarded with caution.

Bepridil↗
PubMed1994

Irreversible, severe congestive cardiomyopathy occurring in association with interferon alpha therapy.

Interferon alpha is a biologic agent with demonstrated anti-tumor activity in a variety of hematologic and solid malignancies. Many patients treated with interferon experience acute toxicity manifested as a flu-like syndrome of fever, chills, myalgias, and malaise. However, fatigue, anorexia, bone marrow suppression, nausea, vomiting, dizziness, and confusion may also occur. Cardiotoxicity is a rare complication of interferon therapy that most frequently presents as transient episodes of hypotension and tachycardia, with few significant life-threatening cardiovascular effects reported. A small number of cases of suspected interferon-induced cardiomyopathy, all of which improved after discontinuing interferon, have recently been documented. We report a patient with multiple myeloma who developed severe congestive cardiomyopathy while receiving interferon alpha that did not reverse subsequent to discontinuation of interferon therapy. Although the patient had previously received doxorubicin, the presence on endomyocardial biopsy of a prominent intracellular lipid accumulation within myocytes and only grade 2 anthracycline cardiotoxicity suggested that other or additional factor(s) contributed to the severity of this patient's cardiomyopathy. Etiologies of cardiac dysfunction other than interferon and doxorubicin were excluded. While a direct cause-effect relationship between interferon alpha and irreversible congestive cardiomyopathy cannot be firmly established in this case report, patients who either concurrently or sequentially receive interferon and anthracyclines should be carefully monitored for evidence of cardiac toxicity.

Combined Modality Therapy↗
PubMed1994

Using control charts to analyze serial patient-related data.

The authors collected data from the record of a patient who had recently undergone coronary bypass surgery and used these data to construct control charts. The control charts helped them to interpret the variation in several clinical parameters and to evaluate the clinical responses to this variation.

Aged↗
PubMed1993

Environmental magnetic fields: influences on early embryogenesis.

A 10-mG, 50 to 60-Hz magnetic field is in the intensity and frequency range that people worldwide are often exposed to in homes and in the workplace. Studies about the effects of 50- to 100-Hz electromagnetic fields on various species of animal embryos (fish, chick, fly, sea urchin, rat, and mouse) indicate that early stages of embryonic development are responsive to fluctuating magnetic fields. Chick, sea urchin, and mouse embryos are responsive to magnetic field intensities of 10-100 mG. Results from studies on sea urchin embryos indicate that exposure to conditions of rotating 60-Hz magnetic fields, e.g., similar to those in our environment, interferes with cell proliferation at the morula stage in a manner dependent on field intensity. The cleavage stages, prior to the 64-cell stage, were not delayed by this rotating 60-Hz magnetic field suggesting that the ionic surges, DNA replication, and translational events essential for early cleavage stages were not significantly altered. Studies of histone synthesis in early sea urchin embryos indicated that the rotating 60-Hz magnetic field decreased zygotic expression of "early" histone genes at the morula stage and suggests that this decrease in early histone production was limiting to cell proliferation. Whether these comparative observations from animal development studies will be paralleled by results from studies of human embryogenesis, as suggested by some epidemiology studies, has yet to be established.

Animals↗
PubMed1993

Evidence for a cannabinoid receptor in sea urchin sperm and its role in blockade of the acrosome reaction.

Delta-9-tetrahydrocannabinol ((-)delta 9 THC), the primary psychoactive cannabinoid in marihuana, reduces the fertilizing capacity of sea urchin sperm by blocking the acrosome reaction that normally is stimulated by a specific ligand in the egg's jelly coat. The bicyclic synthetic cannabinoid [3H]CP-55,940 has been used as a ligand to demonstrate the presence of a cannabinoid receptor in mammalian brain. We now report that [3H]CP-55,940 binds to live sea urchin (Strongylocentrotus purpuratus) sperm in a concentration, sperm density, and time-dependent manner. Specific binding of [3H]CP-55,940 to sperm, defined as total binding displaced by (-)delta 9THC, was saturable: KD 5.16 +/- 1.02 nM; Hill coefficient 0.98 +/- 0.004. This suggests a single class of receptor sites and the absence of significant cooperative interactions. Sea urchin sperm contain 712 +/- 122 cannabinoid receptors per cell. Binding of [3H]CP-55,940 to sperm was reduced in a dose-dependent manner by increasing concentrations of CP-55,940, (-)delta 9THC, and (+)delta 9THC. The rank order of potency to inhibit binding of [3H]CP-55,940 to sperm and to block the egg jelly stimulated acrosome reaction was: CP-55,940 > (-)delta 9THC > (+)delta 9THC. These findings show that sea urchin sperm contain a stereospecific cannabinoid receptor that may play a role in inhibition of the acrosome reaction. The radioligand binding data obtained with live sea urchin sperm are remarkably similar to those previously published by other investigators using [3H]CP-55,940 on mammalian brain and nonneural tissues. The cannabinoid binding properties of this receptor appear to have been highly conserved during evolution. We postulate that the cannabinoid receptor may modulate cellular responses to stimulation.

Acrosome↗
PubMed1993

Band features as classification measures for G-banded chromosome analysis.

Modern automatic and semiautomatic karyotyping systems employ algorithms that use chromosome length and centromeric index as well as other intact chromosome measures. These measures offer correct classification rates near 95%. An algorithm is presented that utilizes local dark band features and position (position from one end of the chromosome, band-width, band-height above light band background, integrated optical density above light band background, and a shape feature) and is based on maximum likelihood of the multivariate normal distribution for the feature vector. The algorithm was tested on two data sets: 179 metaphases from C. Lundsteen at the Rigshospitalet, Copenhagen, and 50 metaphases from The University of Texas M. D. Anderson Cancer Center. The Copenhagen set achieved an overall correct classification rate of 94.6% when classifying itself, a rate comparable to other algorithms. This classifier relies on local band features rather than global chromosome characteristics and is therefore directly extensible to metaphase and prophase chromosome subsegments and to structural abnormalities.

Algorithms↗
PubMed1993

Dietary approaches for reducing fat intake of preschool-age children.

STUDY OBJECTIVE: The present study was conducted to determine the effects of applying different fat reduction strategies to the overall nutrient profile of diets for preschool-age children. DESIGN: Computer modeling techniques were used to modify the diets of children (ages 2 through 3 and 4 through 5 years old) to meet contemporary dietary recommendations (< 30% of calories from total fat, < 10% from saturated fatty acids, and < 300 mg of cholesterol daily). Fat reduction strategies were applied to a 1-week menu that included preschoolers' favorite foods. Strategies applied were replacing high-fat meat exchanges with lean meat exchanges (+/- three high-fat meat exchanges per week), replacing higher fat milks with skim milk, replacing high-fat meat exchanges with medium-fat meat exchanges, using fat-modified products, using low-fat preparation techniques, and added fat. All diets were made isocaloric after modifications were applied. RESULTS: It is more difficult to meet all recommendations for the 2- and 3-year-old children. Use of skim milk is the simplest strategy to use for the 4- and 5-year-old children, although other single strategies are effective. CONCLUSIONS: When multiple strategies are effected. Some diets are very low in fat (< 20% of calories) and potentially inadequate in energy and nutrients. It is important that caregivers know the appropriate foods to choose when modifying fat in children's diets to ensure meeting energy and nutrient requirements.

Child Nutritional Physiological Phenomena↗
PubMed1992

Considerations for the interpretation of findings from single and multiple studies of periodontal conditions.

This paper reviews considerations involved in the interpretation of results of individual periodontal clinical trials and the synthesis of findings of multiple studies. The purpose of each study must be considered, particularly whether it is an epidemiological investigation, prevention trial or therapeutic clinical trial. The definition of clear end-points, whether they be hygiene end-points associated with calculus and plaque or disease end-points that measure extent of gingivitis and periodontitis, is essential. Other statistical considerations include the following: adequate sample size, balanced design, use of covariates, issues of the appropriate sampling unit, and proper statistical analysis. Statistical issues that must be considered include the types of tests of hypotheses, use of multiple comparison procedures when more than two groups are involved, corrections for multiple testing and precise estimation of parameters with corresponding confidence intervals. When comparing across clinical trials, three sources of heterogeneity that must be considered are: treatments, diseases, and target populations. The technique of meta-analysis is described for the statistical interpretation of data arising from several trials. A meta-analysis is conducted for six dental clinical trials that evaluated a triclosan/copolymer formulation for the reduction of plaque, calculus or gingivitis. Results indicate that the first five studies, which were reported simultaneously, showed a common effect, i.e., that the formulation successfully reduced either plaque or calculus. When the sixth study, reported at a different time, was added to the analysis, the collection of studies did not satisfy the homogeneity assumption necessary for estimating a common effect size. This illustrates the importance of testing for homogeneity before pooling possibly dissimilar studies.

Analysis of Variance↗
PubMed1991

Reduction of the fertilizing capacity of sea urchin sperm by cannabinoids derived from marihuana. I. Inhibition of the acrosome reaction induced by egg jelly.

delta 9-Tetrahydrocannabinol (THC) and two other major cannabinoids derived from marihuana--cannabidiol (CBD) and cannabinol (CBN)--inhibit fertilization in the sea urchin Strongylocentrotus purpuratus by reducing the fertilizing capacity of sperm (Schuel et al., 1987). Sperm fertility depends on their motility and on their ability to undergo the acrosome reaction upon encountering the egg's jelly coat. Pretreatment of S. purpuratus sperm with THC prevents triggering of the acrosome reaction by solubilized egg jelly in a dose (0.1-100 microM) and time (0-5 min)-dependent manner. Induction of the acrosome reaction is inhibited in 88.9 +/- 2.3% of sperm pretreated with 100 microM THC for 5 min, while motility of THC-treated sperm is not reduced compared to solvent (vehicle) and seawater-treated controls. The acrosome reaction is inhibited 50% by pretreatment with 6.6 microM THC for 5 min and with 100 microM THC after 20.8 sec. CBN and CBD at comparable concentrations inhibit the acrosome reaction by egg jelly in a manner similar to THC. THC does not inhibit the acrosome reaction artificially induced by ionomycin, which promotes Ca2+ influx, and nigericin, which promotes K+ efflux. THC partially inhibits (20-30%) the acrosome reaction induced by A23187, which promotes Ca2+ influx, and NH4OH, which raises the internal pH of the sperm. Addition of monensin, which promotes Na+ influx to egg jelly or to A23187, does not overcome the THC inhibition. Inhibition of the egg jelly-induced acrosome reaction by THC produces a corresponding reduction in the fertilizing capacity of the sperm. The adverse effects of THC on the acrosome reaction and sperm fertility are reversible.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗