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Biomedical subjects

Y Naveh

Publications and source records attributed to Y Naveh.

At least 19 recordsLinked to original sources
PubMed2005

Interactive virtual environment training for safe street crossing of right hemisphere stroke patients with unilateral spatial neglect.

PURPOSE: The goal of this study was to determine whether non immersive interactive virtual environments are an effective medium for training individuals who suffer from Unilateral Spatial Neglect (USN) as a result of a right hemisphere stroke, and to compare it to a standard computer visual scanning training. METHOD: Participants included 19 patients with right hemisphere stroke in two groups, 11 in an experimental group were given computer desktop-based Virtual Reality (VR) street crossing training and 8 in a control group who were given computer based visual scanning tasks, both for a total of twelve sessions, 9 hours total, over four weeks. Measures included: 1. Standard USN assessments, paper and pencil and ADL checklist; 2. Test on the VR street program; and 3. Actual street crossing videotaped. Testing was performed pre and post intervention. RESULTS: The VR group achieved on the USN measures results that equaled those achieved by the control group treated with conventional visual scanning tasks. They improved more on the VR test and they did better on some measures of the real street crossing. CONCLUSIONS: Despite several limitations in this study the present results support the effectiveness of the VR street program in the treatment of participants with USN, and further development of the program.

Accidents, Traffic↗
PubMed2001

Proximity effect and multiple Andreev reflections in gold atomic contacts.

We investigate the electronic transport properties of gold point contacts with superconducting aluminum leads. The modifications induced by the proximity effect in the quasiparticle density of states at the contact region are measured by tunnel spectroscopy. The theory of transport through multiple Andreev reflections is extended to incorporate these effects and used to determine the number and transmission coefficients of the conduction channels in the contact regime. We find that the smallest contacts, formed by one gold atom between the electrodes, contribute one single channel to the transport with variable transmission T between 0.1 and 1.

Journal Article↗
PubMed2000

Universal distribution of transparencies in highly conductive Nb/AlO(x)/Nb junctions.

We report the observation of the universal distribution of transparencies, predicted by Schep and Bauer [Phys. Rev. Lett. 78, 3015 (1997)] for dirty sharp interfaces, in uniform Nb/AlO(x)/Nb junctions with high specific conductance (10(8) ohm(-1) cm(-2)). Experiments used the BCS density of states in superconducting niobium for transparency distribution probing. Experimental results for both the dc I-V curves at magnetic-field-suppressed supercurrent and the Josephson critical current in zero magnetic field coincide remarkably well with calculations based on the multimode theory of multiple Andreev reflections and the Schep-Bauer distribution.

Journal Article↗
PubMed2000

Absorption of iron in rats with experimental enteritis.

Inflammatory conditions of the gastrointestinal tract and iron-deficiency anemia are very common in humans. Acute intestinal inflammation was pathologically established in rats by intraluminal administration of acetic acid into the duodenum and the proximal jejunum. The study included two control groups of intact (untreated) rats and sham-operated (saline-treated) rats for each intestinal segment. A third group of rats received acetic acid. The acetic acid-induced inflammatory process was established histopathologically and biochemically. Two days after treatment, iron absorption was measured using ligated 10-cm loops of proximal jejunum or ligated duodenum in which 59Fe was injected intraluminally (n = 6 in each group). In another four control groups (intact and sham-operated for each intestinal segment) and two acetic acid-treated groups, serosal-luminal secretion of 59Fe was measured after intravenous injection (n = 5 in each group). 59Fe transfer from the lumens of the duodenum and jejunum to the portal system was significantly lower in those rats in whom inflammation was induced by acetic acid. There was no apparent serosal-luminal secretion of intravenously injected 59Fe in any of the studied groups. We conclude that acetic acid-induced intestinal inflammation significantly reduces iron absorption by the duodenum and the proximal jejunum.

Acetic Acid↗
PubMed2000

Efficacy of bismuth-based triple therapy in children with abdominal pain and Helicobacter pylori gastritis.

BACKGROUND: To evaluate the effect of a therapeutic regimen of 7 days versus 14 days on the clinical manifestations of Helicobacter pylori gastritis in children. METHODS: Ninety children (age 2-19 years) who had abdominal pain and/or recurrent vomiting were determined to have H. pylori gastritis by endoscopy, histology, and a Giemsa stain positive for H. pylori. The patients were randomized to receive amoxicillin, metronidazole, and bismuth subcitrate for 7 days (group A; 45 children) or 14 days (group B; 45 children) and were observed clinically for 19 +/- 11.5 months. Resolution of all abdominal and gastrointestinal symptoms was considered a good response. RESULTS: A good response was obtained in 36 (80%) children from group A, and in 37 (82%) from group B. A recurrence of symptoms occurred in four (11%) of the responders from group A, and in six (15.2%) from group B. CONCLUSIONS: A 7-day course of bismuth-based triple therapy for H. pylori gastritis in children appears to be clinically as effective as a 14-day regimen. The feasibility of a shorter therapeutic regimen may enhance patient compliance and provide a better chance of clinical benefit.

Abdominal Pain↗
PubMed1999

Celiac disease-associated alopecia in childhood.

We report the association of celiac disease and alopecia in 3 children. In one, the alopecia developed after 4 years' nonadherence to a gluten-free diet; the other 2 patients presented with alopecia. Administration of a gluten-free diet resulted in partial regrowth of hair in the first child and complete hair growth in the others.

Adolescent↗
PubMed1997

Progressive familial intrahepatic cholestasis among the Arab population in Israel.

BACKGROUND: Progressive familial intrahepatic cholestasis, which constitutes a heterogeneous group of imperfectly delineated syndromes and appears to be inherited as an autosomal recessive condition, has not been hitherto reported from the Middle East, in spite of the high rate of consanguineous marriage in this region. METHODS: Sixteen affected children from six Israeli Arab families were evaluated over 30 years. All were born to consanguineous parents. RESULTS: Jaundice appeared during the first 3 weeks of life in 15 babies. When first referred, 10 had hepatomegaly and nine had splenomegaly. A progression toward cirrhosis was the rule. Serum levels of conjugated bilirubin, liver enzymes, and alkaline phosphatase were raised; gamma-glutamyl transpeptidase levels were normal in all three infants in whom it was examined, but elevated in two siblings of another family at ages 2 and 3 years. No abnormal bile acids were detected in the serum and urine of patients. Histologic examination of the liver showed giant-cell transformation, paucity of intrahepatic bile ducts, cholestasis, fibrosis, or cirrhosis. The pattern of liver pathology differed at times among affected members within the same family. Therapeutic trials with phenobarbital, cholestyramine, or ursodeoxycholic acid were ineffective. Survival of the patients was from 5 to 18 months in four families; in the other two families, three children received liver transplants, and one is awaiting liver transplantation. CONCLUSIONS: Progressive familial intrahepatic cholestasis should be included in the differential diagnosis of infants with cholestatic jaundice of unknown etiology, especially those born to consanguineous Arab parents.

Arabs↗
PubMed1997

Zinc metabolism in rheumatoid arthritis: plasma and urinary zinc and relationship to disease activity.

OBJECTIVE: To study zinc absorption in patients with active rheumatoid arthritis (RA). METHODS: We studied zinc tolerance tests and 24 hour urinary zinc excretion before and after ingestion of 50 mg elemental zinc in 8 healthy volunteers (Group 1) and 13 patients with low RA activity (Group 2) and 16 patients with high RA activity (Group 3). RESULTS: In Group 1, plasma zinc rose from 111 +/- 7 micrograms/dl to a peak of 200 +/- 24 micrograms/dl (mean +/- SEM) in 2 h. In Groups 2 and 3, plasma zinc before zinc ingestion was significantly lower than that of the control group (p < 0.00001 for both groups) and showed no significant increase in plasma after ingestion. Twenty-four hour urinary zinc excretions before and after zinc ingestion were significantly lower (p < 0.01, p < 0.0001 for Group 2; p < 0.05, p < 0.01 for Group 3, respectively) than those in the control group. CONCLUSION: These results are compatible with zinc malabsorption and consequent zinc deficiency in patients with RA. Whether zinc deficiency contributes to perpetuation of disease activity by compromising cellular immune function needs further investigation.

Adult↗
PubMed1993

Malabsorption of zinc in rats with acetic acid-induced enteritis and colitis.

Acute intestinal inflammation was established in rats by intraluminal administration of acetic acid into loops of distal ileum, proximal jejunum or ascending colon. The study included two control groups of intact (untreated) rats and sham-operated (saline-treated) rats for each intestinal segment. A third group of rats received acetic acid. Histological evaluation demonstrated that acetic acid treatment induced a mild inflammatory response. Two days after treatment, zinc absorption was measured using ligated 10-cm loops of each segment in which 65Zn was injected intraluminally. 65Zn absorption by the ileum, jejunum and colon was markedly reduced in those rats in which inflammation was induced by acetic acid. The liver showed the highest uptake of radioisotope, but the relative tissue distribution generally followed the amount of absorption. The surgical procedure itself seemed to reduce zinc absorption. No changes in [3H]leucine absorption were observed between sham-operated and acetic acid-treated controls. There was no significant serosal-->luminal secretion of intramuscularly injected 65Zn in any of the studied segments. Therefore, based upon the data obtained, we conclude that acetic acid-induced intestinal inflammation reduces absorption of zinc by the small and large intestine, and that a surgical procedure (laparotomy) also reduces zinc absorption. The mechanism of this inflammation is such that malabsorption shows some specificity.

Acetates↗