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Biomedical subjects

I Tamir

Publications and source records attributed to I Tamir.

At least 19 recordsLinked to original sources

Thermal stability comparison of purified empty and peptide-filled forms of a class I MHC molecule.

A secreted form of a class I major histocompatibility complex (MHC) molecule was denatured and renatured in vitro in the absence of peptide. The resulting empty class I heterodimer was immunologically reactive and structurally similar to a heterodimer renatured in the presence of an appropriate restricted peptide. Thermal stability profiles indicated that the two forms of heterodimer differed in their resistance to denaturation by heat but that a significant portion of the empty class I heterodimers had a native conformation at physiological temperatures. Free energies calculated from these data gave a direct measure of the stabilization of the class I MHC molecule that resulted from peptide binding.

Animals

Single-dose ornidazole versus seven-day metronidazole therapy of giardiasis in Kibbutzim children in Israel.

The efficacy of single-dose ornidazole versus seven days metronidazole in the treatment of giardiasis was tested in a randomized study of 75 Kibbutzim children in Israel. All the children treated were clinically cured, and the parasites disappeared from stool examinations after the first follow-up. By the end of the study (21 days after the beginning of treatment), all the patients remained free of symptoms, but cysts of Giardia lamblia were found in the stools of three children from the ornidazole group (p = 0.24). The possibility of treating Giardia lamblia with ornidazole in a single dose, with results similar to those obtained with a seven-day course of metronidazole, makes this drug a good alternative in the treatment of Giardia lamblia in children, especially if compliance is not assured.

Animals

Pancreatic pseudocyst: successful treatment by percutaneous external catheter drainage.

A pseudocyst of the pancreas in a 6-year-old girl persisted for 2 months despite bowel rest and nutritional support. Following percutaneous introduction of a catheter into the cyst under ultrasound guidance and external catheter drainage for 11 days, the pseudocyst resolved completely and permanently. Nonoperative percutaneous techniques for drainage of pancreatic pseudocysts in children may be an effective alternative to surgical intervention.

Catheters, Indwelling

Asymptomatic giardiasis in children.

Giardia lamblia infection was identified in 33 of 89 (37%) 3-month-old to 3-yr-old children who were followed with monthly stool examinations for up to 12 months in a day care center. The infection was mainly asymptomatic and usually associated with prolonged carriage of the parasite. There were no significant differences for height and weight achievements and mean hemoglobin values between Giardia-positive and Giardia-negative children. However, Giardia-positive children tended to achieve higher weight and height for age than Giardia-negative children; weight for age was above the 50th percentile in 69% of Giardia-positive vs. 40% of Giardia-negative children (alpha = 0.01). Giardia-positive children tended to have fewer symptoms related to the gastrointestinal and respiratory tracts as recorded by a weekly questionnaire. Lactase deficiency was detected by breath hydrogen testing in 8 of 26 Giardia-positive vs. only 1 of 21 Giardia-negative children (P less than 0.02). Healthy day care children with asymptomatic Giardia infection show no disadvantage and perhaps even an advantage in nutritional status and freedom from other illnesses.

Body Height

Suckling stimulation test for neonatal tremor.

The response of neonatal tremor to a suckling stimulation test was investigated in 102 healthy neonates born at full term. In 84 the tremor resolved immediately; none had hypocalcaemia and only one had mild hypoglycemia. Eighteen in whom the tremor continued had either hypocalcaemia (n = 13) or hypoglycaemia (n = 5).

Humans

Neutral lipid transfer protein does not regulate alpha-tocopherol transfer between human plasma lipoproteins.

Vitamin E has no known plasma carrier protein and is transported by plasma lipoproteins. The site of association of vitamin E in the lipoprotein particle and the mode of transfer of vitamin E between plasma lipoproteins have not been ascertained. Since neutral lipids (triglycerides and cholesterol esters) exchange between plasma lipoproteins by processes mediated by neutral lipid transfer protein, we questioned that if vitamin E, a hydrophobic molecule, is carried in the core of the lipoprotein particle then its transfer between plasma lipoproteins may be mediated by neutral lipid transfer protein. Transfer of D-alpha(5-methyl-3H)tocopherol from in vitro-labeled human plasma lipoprotein fractions to other plasma lipoproteins was measured under incubation conditions that were designed to yield markedly differing degrees of neutral lipid exchange. Despite the presence of the d greater than 1.21 g/ml lipoprotein-poor plasma fraction or purified lipid transfer protein that resulted in up to a 10-fold increase in neutral lipid transfer, vitamin E transfer between very low density lipoproteins, low density and high density lipoproteins remained constant. Even excess amounts of lipid transfer protein, which caused triglyceride transfer between very low density and high density lipoproteins to reach saturation, failed to affect significantly vitamin E transfer. Vitamin E distribution between lipoprotein fractions did correlated with lipoprotein mass ratios. Vitamin E transfer was higher as the protein ratio of acceptor lipoproteins to donor lipoproteins increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier Proteins

An oral zinc loading test in psoriasis.

Changes of zinc in body fluids were evaluated in 12 patients with extensive psoriasis and compared with those of 11 healthy volunteers, using an oral zinc loading test. Plasma zinc levels and urinary zinc excretion were measured by atomic absorption spectrophotometry. No significant difference was found between plasma zinc levels and urinary zinc excretion following an overnight fast. Both groups showed extensive increases in urinary zinc excretion following the loading test. The peak levels of plasma zinc were significantly lower in the psoriatic patients two and four hours after zinc ingestion (P less than .01 and P less than .02, respectively).

Administration, Oral

Need for endotracheal intubation and suction in meconium-stained neonates.

In a prospective study, we determined whether routine immediate tracheal aspiration at birth is necessary in meconium-stained but otherwise normal infants delivered vaginally and having a 1-minute Apgar score greater than 8. A total of 572 newborn infants who met these criteria were randomly allocated to one of two groups. All infants underwent oropharyngeal suctioning with a DeLee catheter while the head was still on the perineum. In group I (n = 308) suctioning of the trachea under direct vision was performed instantly at birth; in group II (n = 264) this procedure was not done. There was no mortality among infants in the study, but morbidity, mainly pulmonary and laryngeal disorders, occurred in six of 308 group I infants and in none of the group II infants (P less than 0.025). Immediate tracheal suction is not a harmless intervention, and should be considered superfluous in a vigorous term neonate born with meconium-stained amniotic fluid.

Apgar Score

Unexplained neonatal jaundice as an early diagnostic sign of septicemia in the newborn.

This prospective study was performed to determine the frequency of unexplained unconjugated hyperbilirubinemia associated with bacterial infection during the first week of life. Of 5805 infants delivered between September 1984 and December 1986, 93 jaundiced newborns without evidence of septicemia fulfilled the following criteria to be enrolled in the study: weight greater than 2500 g, gestational age greater than 38 weeks, age less than 7 days, and unexplained unconjugated bilirubin greater than 170 mumol/L (greater than 10 mg/dL) during the first 48 hours of life and/or greater than 255 mumol/L (greater than 15 mg/dL) thereafter. Evaluation for septicemia included blood and urine cultures, and white cell and thrombocyte counts. The study disclosed three (3.2%) infants who developed septicemia before any clinical suspicion had been aroused. It is concluded that bacterial infections should be considered a possible cause of neonatal unconjugated hyperbilirubinemia during the first week of life, regardless of the clinical condition of the infant.

Female

Rapid isolation and identification of reovirus-3.

Mammalian reoviruses are connected with a variety of humans diseases, including gastroenteritis, malabsorption and hepatitis. Recently, reovirus-3 was found to be associated with neonatal biliary atresia. We describe a technique for the rapid isolation and identification of reovirus-3. Mouse fibroblasts (L 929 cells) were grown in monolayers in a RPMI 1640 medium containing 10% calf serum. The cytopathic effects were visualized by the rounding of the L 929 cells and the appearance of fine granulation in the cytoplasm 48 h after the infection. Hematoxylin-eosin staining showed swelling and rounding of the infected cells, diminished chromatin in the nuclei, and the absence of mitoses. The immunohistochemical staining by the avidin-biotin-peroxidase technique was positive in the infected monolayers of the L 929 cells. The positive staining was limited to cytoplasmic inclusions, which were surrounded by a halo and sometimes by vacuoles. We conclude that the described technique is useful for the rapid isolation and identification of reovirus-3.

Animals

L-deamino-8-d-arginine vasopressin treatment in pregnancy and neonatal outcome. A report of three cases.

Three women with neurohypophyseal diabetes insipidus, treated for prolonged periods, including pregnancy, with L-deamino-8-d-arginine vasopressin, gave birth in our hospital. Two of the infants had severe congenital heart disease, one of which was associated with trisomy 21. The third baby, born prematurely, presented with mild intrauterine growth retardation; at the age of 21 months, the boy had severe failure to thrive, hypotonia, and motor retardation. These three cases raise doubts as to the safety of diabetes insipidus or its treatment in pregnancy.

Abnormalities, Drug-Induced

Two-hour lactose breath hydrogen test.

Current requirements for the lactose breath hydrogen test (LBHT) include serial expired air samplings and multiple hydrogen (H2) determinations. One hundred thirty-two consecutive LBHTs were evaluated to determine whether multiple samplings are indeed necessary for detection of lactose malabsorption. Expired air samples were collected at 0, 30, 60, 90, 120, 150, and 180 min following ingestion of lactose. Fifty-five LBHTs were positive for lactose malabsorption. All tests showed abnormally elevated breath H2 concentrations at 120 min. The mean value of the change in parts per million (delta ppm) of H2 at 120 min (51.1 +/- 4.7 SEM) was higher than at any other time point. If only the 120-min samples were examined without subtracting the initial concentrations, four of the 77 negative tests (5.2%) would have been falsely positive. Thus, the values of H2 at 0 and 120 min were sufficient to define lactose malabsorption in all cases. We conclude that just as a single blood sample now suffices for determining xylose malabsorption, so expired air sampling at only 0 and 120 min during the LBHT is a reliable method for detecting lactose malabsorption and diminishes the need for acquiring and analyzing multiple samples.

Adolescent

An unusual case of non-traumatic pneumococcal mediastinal abscess.

A 16-month old baby developed severe respiratory failure because of acute laryngitis and required mechanical ventilation. Intubation was complicated by aspiration and development of chemical pneumonia. Following 4 days of treatment the child was successfully extubated. Thirty six hours after extubation the patient again developed respiratory failure and on chest X-ray pneumomediastinum was seen and later evidence of a mediastinal abscess. Conservative treatment, with antibiotics, effected complete cure.

Abscess

Symptomatic sinus bradycardia in infants with structurally normal hearts.

Sixteen infants, ages 6 weeks to 23 months, were evaluated because of syncopal attacks (n = 6), apneic episodes (n = 3), or a combination of syncope, apnea, or "convulsions" (n = 7). Comprehensive metabolic and neurologic investigations yielded negative results in 15 infants; in one, an abnormal EEG was recorded. Severe sinus bradycardia, complete sinus arrest, junctional escape rhythm, or ventricular escape rhythm was found in four patients, and permanent multiprogrammable pacemakers were implanted. Follow-up for 6 to 24 months with ventricular demand pacing showed complete cessation of attacks in two infants and marked improvement in two.

Apnea