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Biomedical subjects

R Zimmerman

Publications and source records attributed to R Zimmerman.

At least 55 records · Page 3Linked to original sources

Tissue lactate in pediatric head trauma: a clinical study using 1H NMR spectroscopy.

In order to define the metabolic abnormalities associated with different types of pediatric head injury, proton magnetic resonance spectroscopy was performed on 21 cerebral regions obtained from 17 patients. On the basis of MRI scans, the regions of interest were classified as normal (6 hemispheres), or showing diffuse axonal injury (3 hemispheres), contusion (4 hemispheres), or cerebral infarction (8 hemispheres). In comparison with normal brain there was no significant elevation in tissue lactate in the diffuse axonal injury patients, but a significant increase in the regions of contusion and infarction. It is concluded that treatment strategies using buffering agents are most likely to benefit these two groups of patients.

Acidosis↗

Effect of verapamil and captopril on endothelial injury in the diabetic hypertensive rat.

Microvascular and macrovascular complications are a major cause of increased morbidity and mortality in patients with diabetes mellitus and hypertension. Atherosclerosis is the major cause of these complications. Recently, Hebden and colleagues demonstrated endothelial injury in a rat model with streptozotocin-induced diabetes mellitus and deoxycorticosterone acetate-induced hypertension. To determine if captopril and verapamil reduce endothelial injury in this model of diabetic hypertensive (DH) rats, we evaluated mean medial thickness and intimal cell changes in four groups of rats: control, untreated DH rats, captopril-treated DH rats, and verapamil-treated DH rats. Mean medial thickness increased from 63.5 +/- 4.8 microns in control rats (n = 7) to 107.2 +/- 7.5 microns in untreated DH rats (n = 8), (P < .05). Verapamil and captopril blunted DH-induced medial thickening to 90.1 +/- 4.9 and 93.7 +/- 8.3 microns, respectively (P < .05 compared with control and untreated rats). An endothelial injury index (EI), consisting of white blood cells adhered to the intimal surface and rounded endothelial cells per 25-microns arc in aortic vessels, was determined for each group. The EI increased from 0.2 +/- 0.1 cells/25-microns arc in control rats to 6.3 +/- 4.0 cells/25-microns arc in untreated DH rats. Both verapamil and captopril diminished the EI in DH rats to 0.8 +/- 0.2 and 2.7 +/- 0.3 cells/25-microns arc, respectively (P < .05 compared with untreated DH rats). In addition, verapamil decreased the EI in DH rats to a greater degree than captopril (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Asthma in children less than 5 years of age: eosinophils and serum levels of the eosinophil proteins ECP and EPX in relation to atopy and symptoms.

Children less than 5 years of age with asthma were assessed for total eosinophil counts and serum levels of the eosinophil proteins, eosinophil cationic protein (ECP) and eosinophil protein X (EPX), to determine whether these measurements would reflect eosinophilic inflammation in the airways. Initially 27 symptomatic patients, 14 atopic and 13 nonatopic were investigated. They had a mean age of 1.8 years and had never been treated with inhaled steroid and had not received Intal for 2 weeks prior to the assessment. The 14 atopic patients proved to have higher mean total eosinophil counts and serum levels of ECP and EPX than the 13 non-atopic patients (eosinophil counts 0.63 x 10(9)/l vs 0.26 x 10(9)/l, P < 0.001; ECP 36.9 micrograms/l vs 10.8 micrograms/l, P < 0.001; EPX 69.0 micrograms/l vs 19.6 micrograms/l, P < 0.01). Thirteen of these patients required treatment with daily doses of inhaled steroid and 11 had a repeat assessment (seven atopic and four non-atopic). The mean serum ECP of the seven atopic patients had fallen significantly (40.6 to 22.9, P < 0.05) while the total eosinophil counts did not. These results suggest a difference in numbers and activity of eosinophils in atopic compared with non-atopic asthma in young children. To determine whether the results were influenced by treatment with inhaled steroids, 31 patients who were being treated with daily inhaled steroid underwent assessment when they were symptomatic (22 samples) or asymptomatic (19 samples). Of the 31 patients, 11 were atopic and 20 non-atopic.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

Magnetic resonance imaging of the cauda equina in Guillain-Barré syndrome.

We report three patients (two children and one adult) with Guillain-Barré syndrome and magnetic resonance imaging evidence of gadolinium enhancement of the cauda equina and lumbar nerve roots. All three patients exhibited symmetric ascending paralysis and areflexia, and two (one child, one adult) suffered urinary incontinence and retention. Similar enhancement has been observed in patients with chronic inflammatory demyelinating polyneuropathy and suggests proximal nerve inflammation. Magnetic resonance imaging in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy may have diagnostic utility.

Cauda Equina↗

High-resolution 1H-magnetic resonance spectroscopy of pediatric posterior fossa tumors in vitro.

High-resolution proton magnetic resonance (MR) spectroscopy was performed on perchlorate extracts of tumors (24 cases) or peritumoral vermis (five cases) obtained at surgery. Fifteen tumors were typical cerebellar astrocytomas and nine were posterior fossa primitive neuroectodermal tumors/medulloblastomas. Spectra obtained from the five samples of peritumoral vermis revealed a pattern of metabolites similar to that reported for cerebellar tissue, but concentrations of most metabolites were low, perhaps due to dilution from peritumoral edema. The astrocytomas were characterized by high levels of valine, alanine, and choline, an increase in the choline:N-acetylaspartate (NAA) ratio, and a shift from glutamate to glutamine. Elevations in lactate, pyruvate, and glucose were the result of ischemia during sampling. The primitive neuroectodermal tumors/medulloblastomas were distinguished from astrocytomas by a greater increase in the choline:NAA ratio, a smaller decrease in the glutamate:glutamine ratio, and a relative increase in glycine, taurine, and inositol levels. These metabolic patterns may be of value diagnostically as in vivo MR spectroscopy achieves higher resolution.

Adolescent↗

Hot-knife conization of the cervix: clinical and pathologic findings from a study introducing a new technique.

OBJECTIVE: To introduce an alternative method for conization of the cervix using a Teflon-coated hot knife and to evaluate thermal distortion, adequacy of excision, operating time, blood loss, and short- and long-term effects of this method. METHODS: Between 1987-1993, 88 patients underwent cervical conization using a Teflon-coated hot knife at temperatures ranging from 110-130C. Histopathologic slides were reviewed simultaneously by two pathologists, who assessed thermal distortion, adequacy of excision, and interpretability of the surgical margins. Clinical information was obtained prospectively, including operating time, blood loss, and depth and volume of the excised cone. In addition, data were accumulated retrospectively from 40 randomly selected patients who underwent cold-knife conization between 1985-1990. Short- and long-term data were assessed for healing and scarring and the adequacy of postoperative Papanicolaou smears in the hot-knife patients. RESULTS: Thermal injury was minimal, with 300 mu or less in 83 patients (92%) and 350-600 mu in four patients. One patient had thermal distortion of 1500 mu. All slides were interpreted adequately. Blood loss was mild to moderate in 84 of 88 patients (95%) in the hot-knife group and in 34 of 40 patients (85%) in the cold-knife group. No patient in the hot-knife group needed blood transfusion or hospitalization. Operating time was reduced by as much as 67% when the hot knife was used. Thirteen percent of the hot-knife patients developed stenosis of the external os. No patient in the hot-knife group developed recurrence within 2 years of surgery. CONCLUSION: Using a Teflon-coated hot knife for conization of the cervix produces adequate surgical margins and reduces blood loss and operating time over that with cold-knife conization. Long-term follow-up reveals no increase in cervical stenosis and demonstrates adequate cytologic smears in the hot-knife patients.

Adolescent↗

Cognitive-behavioral group psychotherapy of bulimia nervosa: importance of logistical variables.

Although much of the psychotherapy for psychiatric disorders is conducted on a weekly basis, several researchers in the field of bulimia nervosa have utilized a more intensive approach as a means to strengthen treatment effects. A second issue concerns the amount of emphasis that should be placed on encouraging the interruption of bulimic symptoms early in treatment. In the current study we systematically studied these two issues. Subjects were randomly assigned to one of four forms of cognitive-behavioral group psychotherapy, the four cells differing on the variables of intensity and emphasis on abstinence. The results indicate that a high intensity approach, an early abstinence approach, or a combination of these two approaches are all significantly more effective in inducing remission in patients with bulimia nervosa compared with a weekly psychotherapy that uses the same manual-based cognitive-behavioral therapy approach.

Adolescent↗

Magnetic resonance scans should replace biopsies for the diagnosis of diffuse brain stem gliomas: a report from the Children's Cancer Group.

Children's Cancer Group Protocol CCG-9882 was designed to determine the effectiveness of hyperfractionated radiation for the treatment of children and young adults with brain stem gliomas. The study opened for the accrual of patients on September 21, 1988, and was closed on June 30, 1991. The first 54 children in the study were treated with irradiation doses of 100 cGy given twice daily to a total dosage of 7200 cGy. The next 66 children were treated with a similar daily regimens to a total of 7800 cGy. Tumors were diagnosed by clinical and radiographic criteria. Decisions about the need for surgery were left to the discretion of the treating neurosurgeon; tissue diagnosis did not alter the therapy in patients with diffuse infiltrating tumors. We reviewed the neuroradiology and neurosurgery reports as well as the pathological specimens of children entered on the study. By magnetic resonance (MR) imaging criteria, tumors involved the majority of the brain stem in 76% of cases; only three patients had tumors localized to the midbrain or medulla. Operations were performed on 56 of 120 patients (47%). Cerebrospinal fluid shunts were inserted in 27 (23%) of the children; insertion of a shunt was the only operation in 11, and a shunt was inserted in conjunction with a tumor operation in 16. Tumor operations were performed in 45 (38%) of the patients; 24 had stereotactic biopsies, and 21 had craniotomies. Of the 21 patients who had craniotomies, only biopsies were performed in 11; partial tumor resections were performed in 5 patients and subtotal resection in 5.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

The relationship of drug use to suicide ideation and attempts among African American, Hispanic, and white non-Hispanic male adolescents.

This study presents self-report cross-sectional and longitudinal data on associations between drug use, suicide ideation, and attempts in a multiethnic sample of seventh- and eighth-grade male adolescents attending school in the greater Miami, Florida, area. African Americans had the highest prevalence of 6-month ideation (20.5%), and Haitians had the highest attempts (11.4%). For the total sample, tranquilizers had the highest odds ratio for ideation (3.4), and PCP for attempts (6.2). Psychoactive drug-use was consistently related to attempts among Hispanics, white non-Hispanics, and African Americans. Acculturation strains interacted with cocaine and crack to predict suicide attempts among Hispanic respondents.

Acculturation↗

Striking inverse association of IgG-anti-Fab gamma antibodies and CD4 cell counts in patients with acquired immunodeficiency syndrome (AIDS)/AIDS-related complex.

The contribution of autoimmune phenomena to the pathogenesis of acquired immunodeficiency syndrome (AIDS) is poorly understood. We investigated the relationship between IgG-anti-Fab gamma autoantibodies and the main immunologic feature of AIDS, the decrease of CD4+ helper lymphocytes. Sera of 33 human immunodeficiency virus (HIV) infected (HIV+) hemophilia patients with AIDS/AIDS-related complex (ARC), 57 HIV+ patients without AIDS/ARC, 23 HIV-negative (HIV-) patients, and 76 healthy controls were tested for antibody activity against the Fab region of IgG. Patients with AIDS/ARC had significantly higher IgG-anti-Fab gamma activity than HIV+ patients without AIDS/ARC, HIV- patients, or controls (P less than .0001). A striking inverse association was found between IgG-anti-Fab gamma and CD4+ cell counts (r = -.69; P less than 10(-6)). Sequential testing in 16 AIDS/ARC patients showed that an increase in the IgG-anti-Fab gamma activity was invariably accompanied by a decrease in the CD4+ cell count. IgG-anti-Fab gamma antibodies may play an important role in the immunopathogenesis of AIDS.

AIDS-Related Complex↗

Quantitative MRI studies for assessment of multiple sclerosis.

Although magnetic resonance imaging (MRI) is a valuable aid in the initial diagnosis of multiple sclerosis (MS), quantitatively MRI has been disappointing in staging and evaluating therapy protocols by means of serial examinations. In this study, image processing algorithms were developed for the global analysis of MR images of the cerebrum. Limited three-dimensional segmentation was achieved through histogram analysis by these algorithms, which are essentially operator independent. The effects of coil response and tip angles, patient positioning, and interslice gap thicknesses were examined for 10 MS patients with repeated examinations for a total of 72 images. Effects of technique and instrumentation errors were approximately 6%, and agreement between two independent operators for measuring the total MR pixel sum from periventricular effusions and intense MS plaques was better than 97% with a standard deviation of 2.9%.

Adipose Tissue↗

Protein export in prokaryotes and eukaryotes. Theme with variations.

Protein export in prokaryotes as well as in eukaryotes can be defined as protein transport across the plasma membrane. In both types of organisms there are various apparently ATP-dependent transport mechanisms which can be distinguished from one another and which show similarities when the prokaryotic mechanism is compared with the respective eukaryotic mechanism. First, one can distinguish between transport mechanisms which involve so-called signal or leader peptides and those which do not. The latter mechanisms seem to employ ATP-dependent transport systems which belong to the family of oligopeptide permeases and multiple drug resistance proteins. Second, in signal or leader peptide-dependent transport one can distinguish between transport mechanisms which involve ribonucleoparticles and those which employ molecular chaperones. Both mechanisms appear to converge at the level of ATP-dependent translocases.

Animals↗