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Biomedical subjects

M Stein

Publications and source records attributed to M Stein.

At least 37 records · Page 2Linked to original sources
PubMed2001

Motor sequencing deficits in schizophrenia: a comparison with Parkinson's disease.

Motor abnormalities occur in schizophrenia (SZ) and may arise from striatal dysfunction. This study examined whether the pattern of performance on simple and complex motor abilities in SZ was similar to that of patients with Parkinson's disease (PD). Quantitative tests of speeded movement and motor and cognitive sequencing were used to assess 25 SZ, 16 PD, and 84 normal controls (NCs). Sequencing performance was also examined with motor rigidity taken into account. Compared with the NC group, the SZ and PD groups were impaired on measures of motor rigidity and motor sequencing. With rigidity accounted for, the SZ group was significantly more impaired than the PD group on motor sequencing; cognitive and motor processes contributed to the motor deficit. Cognitive sequencing performance predicted motor sequencing performance in PD but not SZ. Although both SZ and PD resulted in significant motor and cognitive sequencing deficits, the pattern and correlates of these deficits differ, suggesting that the affected neural systems underlying motor deficits in SZ are different from those involved in PD.

Adult↗
PubMed2001

[Follow-up in patients with head and neck tumors: evaluation of CT criteria for local tumor recurrence].

BACKGROUND: Aim of this study was to evaluate morphologic criteria for diagnosis of locally recurrent head and neck tumors in helical CT. METHODS: Retrospective study, 44 examinations with radiologically abnormal findings were re-read by two radiologists; findings were analysed and correlated with histological diagnosis and clinical findings. RESULTS: 25 cases of local tumor recurrence were confirmed histologically. The accuracy of helical-CT in our preselected examinations for a local tumor recurrence was 93.5 %, the specificity 83.3 %. But 13/44 cases showed radiologically equivocal findings, among them 6 tumor recurrences. The most common characteristics of the 25 proven tumor recurrences were: contrast medium enhancement (96 %), increased volume in comparison to previous examination (92 %), inhomogenity (72 %); however contrast medium-enhancement and increasing volume were also seen in 68.4 % and 63.1 % of the benign changes. CONCLUSION: Contrast medium enhancement and increasing volume are criteria with a high sensitivity but low specifity in predicting a local tumor recurrence in head and neck cancer.

Carcinoma, Squamous Cell↗
PubMed2001

Helminths, human immunodeficiency virus and tuberculosis.

Helminth infections affect over a quarter of the world's population, especially in the developing countries. These long-lasting parasitic infections cause widespread immune activation and dysregulation, a dominant Th2 cytokine immune profile and an immune hyporesponsiveness state. Considering these profound immune changes and the similar geographic distributions of helminthic infections, HIV and tuberculosis (TB), we suggest that helminthic infections play a major role in the pathogenesis of AIDS and TB. They apparently make the host more susceptible to infection by HIV and Mycobacterium tuberculosis, and impair his/her ability to generate protective immunity against both infections. The implication of these ideas is that without eradication of helminth infections and/or modulation of the immune changes that they cause, HIV and TB vaccines may fail to confer protection against their respective infections in helminth-endemic areas.

AIDS-Related Opportunistic Infections↗
PubMed2001

Intravenous rFVIIa administered for hemorrhage control in hypothermic coagulopathic swine with grade V liver injuries.

BACKGROUND: Intravenous administration of recombinant activated human clotting factor VII (rFVIIa) has been used successfully to prevent bleeding in hemophilia patients undergoing elective surgery, but not in previously normal trauma patients. This study was conducted to determine whether rFVIIa was a useful adjunct to gauze packing for decreasing blood loss from grade V liver injuries in hypothermic and coagulopathic swine. METHODS: All animals (n = 10, 35 +/- 2 kg) underwent a 60% isovolemic exchange transfusion with 6% hydroxyethyl starch and were cooled to 33 degrees C core temperature. The swine then received a grade V liver injury and 30 seconds later, either 180 microg/kg rFVIIa, or saline control. All animals were gauze packed 30 seconds after injury and resuscitated 5.5 minutes after injury with lactated Ringer's solution to their preinjury mean arterial pressure. Posttreatment blood loss, mean arterial pressure, resuscitation volume, and clotting studies were monitored for 1 hour. Histology of lung, kidney, and small bowel were obtained to evaluate for the presence of microvascular thrombi. RESULTS: At the time of injury, core temperature was 33.3 degrees +/- 0.4 degrees C, hemoglobin was 6 +/- 0.7 g/dL, prothrombin time was 19.1 +/- 1.0 seconds, activated partial thromboplastin time was 29.0 +/- 4.8 seconds, fibrinogen was 91 +/- 20 mg/dL, and platelets were 221 +/- 57 x 105/mL, with no differences between groups (p > 0.05). Clotting factor levels confirmed a coagulopathy at the preinjury point. The posttreatment blood loss was less (p < 0.05) in group 1 (527 +/- 323 mL), than in group 2 (976 +/- 573 mL). The resuscitation volume was not different (p > 0.05). One-hour survival in both groups was 100%. Compared with the control group, rFVIIa increased the circulating levels of VIIa and, despite hypothermia, shortened the prothrombin time 5 minutes after injection (p < 0.05). Laboratory evaluation revealed no systemic activation of the clotting cascade. Postmortem evaluation revealed no evidence of large clots in the hepatic veins or inferior vena cava, or microscopic thrombi in lung, kidney, or small intestine. CONCLUSION: rFVIIa reduced blood loss and restored abnormal coagulation function when used in conjunction with liver packing in hypothermic and coagulopathic swine. No adverse effects were identified.

Animals↗
PubMed2001

Diagnostic medical auxiliary equipment in a field hospital: experience from the Israeli delegation to the site of the Turkish earthquake at Adapazari.

An earthquake striking a highly populated area is likely to cause a mass casualty situation for even the most advanced trauma center. If the local medical teams are injured and the hospitals are damaged beyond immediate repair, external intervention is needed. In the Turkish earthquake crisis, Israel was one of many states to deploy a field hospital to the crisis site. This was set up in Adapazari, the second most severely hit city in terms of the amount of damage. The hospital provided advanced surgical and medical facilities, including laparotomy, cesarean section, and intensive care surveillance. These facilities require sophisticated laboratory and radiology services, including hematology, chemistry, microbiology, and blood bank. The speed with which the hospital must be assembled and transported to be efficient and the basic conditions of a field hospital dictate specific considerations regarding diagnostic auxiliary equipment. Considerations in choosing this equipment, problems encountered during installation, and recommendations for the future are presented.

Diagnostic Equipment↗
PubMed2001

Contamination of soils with eggs of Toxocara in a subtropical city in Argentina.

A total of 475 soil samples were collected from five public park playgrounds, 17 kindergarten sandpits and 124 housing estates in Resistencia, a medium-sized subtropical-region city in Argentina, and processed by the centrifugal flotation method. Eggs of Toxocara spp. were present in five (3.4%) of the 146 habitats surveyed and in six (1.3%) of the 475 samples examined. Twenty per cent of public parks, 5.9% of kindergarten sandpits and 2.4% of housing estates were contaminated with Toxocara eggs. Depending on the number of samples examined from the three types of habitat, contamination by Toxocara was 0.7% in public park playgrounds, 1.2% in kindergarten sandpits and 1.6% in the housing estates. High prevalences of Ancylostomidae eggs were also found especially in public park playgrounds with a value of 100%, compared with 19.4% found in housing estates and 11.8% in kindergarten samples. These results suggest that in Resistencia, human infections with Toxocara are likely to occur within the limits of housing estates more so than in public parks or open spaces.

Ancylostoma↗
PubMed2000

The neuropathic postural tachycardia syndrome.

BACKGROUND: The postural tachycardia syndrome is a common disorder that is characterized by chronic orthostatic symptoms and a dramatic increase in heart rate on standing, but that does not involve orthostatic hypotension. Several lines of evidence indicate that this disorder may result from sympathetic denervation of the legs. METHODS: We measured norepinephrine spillover (the rate of entry of norepinephrine into the venous circulation) in the arms and legs both before and in response to exposure to three stimuli (the cold pressor test, sodium nitroprusside infusion, and tyramine infusion) in 10 patients with the postural tachycardia syndrome and in 8 age- and sex-matched normal subjects. RESULTS: At base line, the mean (+/-SD) plasma norepinephrine concentration in the femoral vein was lower in the patients with the postural tachycardia syndrome than in the normal subjects (135+/-30 vs. 215+/-55 pg per milliliter [0.80+/-0.18 vs. 1.27+/-0.32 nmol per liter], P=0.001). Norepinephrine spillover in the arms increased to a similar extent in the two groups in response to each of the three stimuli, but the increases in the legs were smaller in the patients with the postural tachycardia syndrome than in the normal subjects (0.001+/-0.09 vs. 0.12+/-0.12 ng per minute per deciliter of tissue [0.006+/-0.53 vs. 0.71+/-0.71 nmol per minute per deciliter] with the cold pressor test, P=0.02; 0.02+/-0.07 vs. 0.23+/-0.17 ng per minute per deciliter [0.12+/-0.41 vs. 1.36+/-1.00 nmol per minute per deciliter] with nitroprusside infusion, P=0.01; and 0.008+/-0.09 vs. 0.19+/-0.25 ng per minute per deciliter [0.05+/-0.53 vs. 1.12+/-1.47 nmol per minute per deciliter] with tyramine infusion, P=0.04). CONCLUSIONS: The neuropathic postural tachycardia syndrome results from partial sympathetic denervation, especially in the legs.

Adult↗
PubMed2000

Delayed medical care after diagnosis in a US national probability sample of persons infected with human immunodeficiency virus.

OBJECTIVE: To identify health care and patient factors associated with delayed initial medical care for human immunodeficiency virus (HIV) infection. DESIGN: Survey of a national probability sample of persons with HIV in care. SETTING: Medical practices in the contiguous United States. PATIENTS: Cohort A (N = 1540) was diagnosed by February 1993 and was in care within 3 years; cohort B (N = 1960) was diagnosed by February 1995 and was in care within 1 year of diagnosis. MAIN OUTCOME MEASURE: More than 3- or 6-month delay. RESULTS: Delay of more than 3 months occurred for 29% of cohort A (median, 1 year) and 17% of cohort B. Having a usual source of care at diagnosis reduced delay, with adjusted odds ratios (ORs) of 0.61 (95% confidence interval [CI], 0.48-0.77) in cohort A and 0. 70 (95% CI, 0.50-0.99) in cohort B. Medicaid coverage at diagnosis showed lower adjusted ORs of delay compared with private insurance (cohort A: adjusted OR, 0.52; 95% CI, 0.30-0.92; cohort B: adjusted OR, 0.48; 95% CI, 0.27-0.85). Compared with whites, Latinos had 53% and 95% higher adjusted ORs of delay (P<.05) in cohorts A and B, respectively, and African Americans had a higher adjusted OR in cohort A (1.56; 95% CI, 1.19-2.04). The health care factors showed similar effects on delay of greater than 6 months. CONCLUSIONS: Medicaid insurance and a usual source of care were protective against delay after HIV diagnosis. After full adjustment, delay was still greater for Latinos and, to a lesser extent, African Americans compared with whites.

Adult↗
PubMed2000

Structure-activity studies including a Psi(CH(2)-NH) scan of peptide YY (PYY) active site, PYY(22-36), for interaction with rat intestinal PYY receptors: development of analogues with potent in vivo activity in the intestine.

Peptide YY (PYY) is a gut hormone that inhibits secretion and promotes absorption and growth in the intestinal epithelium. We have performed structure-activity studies with the active site, N-alpha-Ac-PYY(22-36)-NH(2), for interaction with intestinal PYY receptors. Investigation of aromatic substitutions at position 27 resulted in analogues that exhibited potent in vitro antisecretory potencies with N-alpha-Ac-[Trp(27)]PYY(22-36)-NH(2) exhibiting even greater potency than intact PYY. In vivo studies in dogs revealed that this analogue also promoted intestinal absorption of water and electrolytes during continuous intravenous and intraluminal infusion. Investigations carried out to identify features that would enhance stability revealed that incorporation of Trp(30) increased affinity for PYY receptors. A "CH(2)-NH" scan revealed that incorporation of reduced bonds at position 28-29 or 35-36 imparted greater receptor affinity. In general, disubstituted analogues designed based on the results of single substitutions exhibited good receptor affinity with N-alpha-Ac-[Trp(27),CH(2)-NH(35-36)]PYY(22-36)-NH(2) having the greatest affinity (IC(50) = 0.28 nM). Conservative multiple substitutions with Nle-->Leu and Nva-->Val also imparted good affinity. An analogue designed to encompass most of the favored substitutions, N-alpha-Ac-[Nle(24,28),Trp(30),Nva(31), CH(2)-NH(35-36)]PYY(22-36)-NH(2), exhibited a proabsorptive effect in dogs comparable to, but longer lasting than, that of intact hormone. Selected analogues also exhibited good antisecretory potencies in rats with N-alpha-Ac-[Trp(30)]PYY(22-36)-NH(2) being even more potent than PYY. However, the potencies did not correlate well with the PYY receptor affinity or the proabsorptive potencies in dogs. These differences could be due to species effects and/or the involvement of multiple receptors and neuronal elements in controlling the in vivo activity of PYY compounds. PYY(22-36) analogues exhibited good affinity for neuronal Y2 receptors but poor affinity for Y1 receptors. Also, crucial analogues in this series hardly bound to Y4 and Y5 receptors. In summary, we have developed PYY(22-36) analogues which, via interacting with intestinal PYY receptors, promoted potent and long-lasting proabsorptive and antisecretory effects in in vivo models. These compounds or analogues based on them may have useful clinical application in treating malabsorptive disorders observed under a variety of conditions.

Animals↗
PubMed2000

Physical and sexual abuse in women infected with the human immunodeficiency virus: increased illness and health care utilization.

BACKGROUND: A history of physical or sexual abuse is associated with increased health care utilization and possibly an increase in illness based largely on self-reported data. OBJECTIVE: To examine whether victimization experience is associated with increases in documented medical disease and health care utilization among women infected with the human immunodeficiency virus (HIV). METHODS: We interviewed and reviewed medical record data of 50 women seeking initial primary care for HIV infection at 2 urban hospitals. Women with and without a history of physical and sexual abuse were compared. Using multiple regression analysis, 2 periods were examined: entire life before study entry and the subsequent 2 years. The characteristics examined included episodic disease, chronic disease, sexually transmitted disease, chronic pain syndrome, opportunistic infections, obstetrical history, and number of injuries, surgical procedures, hospitalizations, ambulatory care visits, and emergency department visits. RESULTS: Evidence of physical or sexual abuse was found in 34 (68%) of the 50 women, of whom 16 (32%) did not disclose during the interview that they were abused. At entry, the rates of episodic disease, chronic pain syndrome, and sexually transmitted disease were greater among those women with histories of abuse. At 2 years, episodic disease, chronic disease, injuries, emergency department visits, and hospitalizations were all more likely in abused women. CONCLUSION: Physical and sexual abuse are common and associated with increased medical disease and health care utilization among HIV-infected women.

Adult↗
PubMed2000

Nestin-expressing cells in the pancreatic islets of Langerhans.

The pancreatic islets of Langerhans produce several peptide hormones, predominantly the metabolically active hormones insulin and glucagon, which are critical for maintaining normal fuel homeostasis. Some evidence exists that pancreatic endocrine cells turn over at a slow rate and can regenerate in certain conditions. This could be due to the presence of pluripotent cells residing in the pancreas. Recently the intermediate filament protein nestin has been identified to be a marker for a multipotent stem cell in the central nervous system. Given the similarity between the pancreatic islets and neuronal cells, we hypothesized that stem cells expressing nestin might be present in the pancreas. Here we present evidence that a subset of cells in the pancreatic islets express the stem cell marker nestin. These cells might serve as precursors of differentiated pancreatic endocrine cells.

Animals↗
PubMed2000

A prospective study on the incidence and clinical relevance of heparin-induced antibodies in patients after vascular surgery.

The heparin-platelet factor 4-antibody assay, polyanion-platelet factor 4-antibody assay and heparin-induced platelet activation test are used for laboratory diagnosis of the immune form of heparin-induced thrombocytopenia. Fifty consecutive patients receiving heparin treatment for more than 5 days after vascular surgery were prospectively screened for heparin-induced thrombocytopenia antibodies, thrombocytopenia (daily platelet counts), deep-vein thrombosis (color-coded duplex sonography), and arterial reocclusion (clinical assessment). None of the patients developed thrombocytopenia or thrombosis in association with formation of heparin-induced thrombocytopenia antibodies. Despite the absence of clinical evidence of heparin-induced thrombocytopenia, many patients formed heparin-induced thrombocytopenia antibodies: 34% of the patients were positive in the heparin-platelet factor 4-antibody assay, 28% in the polyanion-platelet factor 4-antibody assay, 14% in the heparin-induced platelet activation test, and 54% with any of these tests. Patients predominantly developed IgM (24%) and IgA antibodies (16%), whereas IgG antibodies were found in 12% of patients. Whereas the majority of patients with positive ELISA assays had IgM and IgA antibodies, patients with a positive functional assay (heparin-induced platelet activation test) predominantly had IgG antibodies. We conclude that a high percentage of patients develop heparin-induced antibodies after vascular surgery without any clinical symptoms of heparin-induced thrombocytopenia. None of the assays therefore is predictive of the clinical manifestation of heparin-induced thrombocytopenia in asymptomatic patients. Therefore, the diagnostic specificity of both antigen and activation assays for heparin-induced thrombocytopenia appears to be relatively low in the vascular surgery patient population.

Aged↗
PubMed2000

Tyrosine phosphorylation of the Helicobacter pylori CagA antigen after cag-driven host cell translocation.

Helicobacter pylori strains associated with severe tissue damage and inflammation possess a unique genetic locus, cag, containing 31 genes originating from a distant event of horizontal transfer and retained as a pathogenicity island. The cag system is an Helicobacter-specific type IV secretion engine involved in cellular responses like induction of pedestals, secretion of IL-8, and phosphorylation of proteic targets. It has previously been reported that cocultivation of epithelial cells with Helicobacter pylori triggers signal transduction and tyrosine phosphorylation of a 145-kDa putative host cell protein. Herein, we demonstrate that this protein is not derived from the host but rather is the bacterial immunodominant antigen CagA, a virulence factor commonly expressed in peptic ulcer disease and thought to be an orphan of a specific biological function. Thus, CagA is delivered into the epithelial cells by the cag type IV secretion system where it is phosphorylated on tyrosine residues by an as yet unidentified host cell kinase and wired to eukaryotic signal transduction pathways and cytoskeletal plasticity.

Antigens, Bacterial↗
PubMed2000

Comparing thyroid ultrasonography to thyroid function in long-term survivors of childhood lymphoma.

BACKGROUND: We studied the value of thyroid ultrasonography as a follow-up tool in survivors of childhood lymphomas and correlated morphologic abnormalities with thyroid function tests. PROCEDURE: A prospective follow-up study of 45 long-term survivors of histology-proved childhood lymphomas was performed. Mean age at diagnosis was 9.1 years (range 2.1-16.4 years) and mean follow-up duration 10.9 years (range 3.9-22.2 years). RESULTS: Among the 26 survivors of Hodgkin disease (HD) who received mantle field irradiation, 14 (54%) had abnormal ultrasonograms. Elevated thyroid-stimulating hormone (TSH) concentrations were found in 14 (54%), and 6 of them (42%) had normal thyroid functions. Six of twelve patients with normal ultrasonograms had abnormal thyroid function, and 5 of 11 patients with normal function had abnormal sonograms. Among the 19 non-HD survivors who did not receive radiotherapy, 18 (95%) had both normal sonograms and normal function. Thus thyroid gland abnormalities were detected in 54% of HD survivors after mantle field irradiation. No correlation between the abnormalities detected on ultrasonography and serum levels of TSH and thyroid hormones were found. CONCLUSIONS: Both ultrasound and thyroid function tests independently provide clinically useful information; the former examines gland morphologogy and the latter evaluates hormonal changes associated with thyroid disease. The high frequency of thyroid abnormalities detected by ultrasonography suggests that periodic thyroid ultrasonography is advisable in the follow-up of patients treated with mantle irradiation to screen for morphologic changes that may presage malignant transformation.

Adolescent↗