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Biomedical subjects

I Zahavi

Publications and source records attributed to I Zahavi.

At least 73 records · Page 4Linked to original sources
PubMed1987

Distributions of total cholesterol, triglycerides, and high-density lipoprotein cholesterol in Israeli Jewish children of different geographic-ethnic origins, ages 9-17 years.

To determine age and ethnic patterns of blood lipid levels in childhood and adolescence and to extend previous adult and late adolescent Israeli data to prepubertal ages, the levels of plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were determined among 1,153 schoolchildren in the area of Petah-Tikva. Half of the children were born to immigrants from Yemen. Among boys, TC levels progressively decreased as age increased from 10-11 to 14-15 years (159 to 142 mg/dl). The age-specific TC and HDL-C means among boys are compatible with an initial swift fall with age, followed by a rise restricted to TC during puberty. Among girls, progressively lower means through ages 12-13 and increasingly higher ones for older age groups are also compatible with puberty-determined changes, previously observed in American cohorts. The differences in TC were only partly accounted for by lower HDL-C means at higher ages (52 mg/dl in the youngest and 45 mg/dl in the oldest age group, respectively, among boys, compared with 53 mg/dl for girls at both ages 9 and 16-17). TG levels in boys, but not in girls, showed age differences paralleling those found for HDL-C, but in an inverse direction. TC means were lower as age increased only among female offspring of European-born Jews (159 to 148 mg/dl, ages 9-12 compared with ages 13-17), a phenomenon that requires further study. Overall, TC and HDL-C were clearly higher among girls than boys beginning at ages 12-13, with little or no sex differences in TG. The sex differences in TC, contrary to previous studies, were not fully accounted for by HDL-C sex differences. The ethnic variability paralleled previous findings in Israeli adults and adolescents, showing low TC levels among male offspring of Yemenite and other Asian-born fathers. The ethnic differences among girls were small. No specific pattern of age-related lipid changes was found in the group of Yemenite origin, who represented offspring of parents with notoriously low levels of coronary heart disease incidence.

Adolescent↗
PubMed1987

Pentagastrin protects the proximal small intestine against indomethacin-induced ulcers in the rat.

The possible protective effects of pentagastrin on indomethacin-induced small intestinal ulceration were investigated in rats. Ulcers were induced by subcutaneous injection of 30 mg/kg indomethacin, 30 min after refeeding rats fasted for 24 h. Administration of pentagastrin at a dose of 250 or 400 micrograms/kg i.p., 3 h prior to refeeding, reduced total ulcer area from 27.6 +/- 6.5 to 7.2 +/- 1.97 mm2 (mean +/- SEM; p less than 0.02) in the proximal small intestine only. Cyclic adenosine monophasphate, but not prostaglandin E2 levels were significantly raised by 250 micrograms/kg pentagastrin (0.15 +/- 0.05 vs. 0.38 +/- 0.07 pmol/mg protein; mean +/- SEM; p less than 0.02) in the same intestinal segment.

Animals↗
PubMed1987

Effects of parenteral and enteral nutrition on postnatal development of the small intestine and pancreas in the rabbit.

Although TPN is used frequently in young infants, little information is available regarding its effect on postnatal development of the gut. The effect of total parenteral nutrition (TPN) and intragastric (IG) alimentation on ontogeny of the small intestine was examined in infant rabbits starting at 10-12 days. Animals were killed at 17-19 days. Body weight, organ weight and weight of segments of proximal, mid and distal small intestine were measured. Intestinal mucosa was scraped, weighed and homogenized for estimation of protein, DNA and disaccharidases. Na+ transport was examined in short-circuited jejunum. Weight gain was similar in controls, sham-treated and TPN animals, but was significantly reduced in IG animals. TPN induced precocious development of sucrase and maltase activity and glucose-stimulated Na+ transport, despite causing a significant decrease in mucosal weight and DNA and pancreatic amylase. IG alimentation also induced precocious development of sucrase, maltase and glucose-stimulated Na+ transport. Thus TPN, despite producing mucosal atrophy and decreased pancreatic exocrine development, stimulates accelerated postnatal maturation of the small intestine.

Animals↗
PubMed1987

Effect of pentoxifylline on E-rosette formation and on the mitogenic response of human mononuclear cells.

Pentoxifylline (Trental) has been shown to increase the intracellular cAMP concentration. In the present study we have examined the capacity of the drug to affect E-rosette formation by T lymphocytes. In addition, the mitogenic response of human lymphocytes to phytohemagglutinin (PHA) and concanavalin A (con A) was studied. The drug exerted a dose dependent inhibitory effect on E-rosette formation and on the proliferative response of lymphocytes to PHA and con A. It is suggested that this inhibitory effect is most probably due to the increased intracellular levels of cAMP induced by the drug.

Adult↗
PubMed1986

Effect of pentoxifylline on the phagocytic activity, cAMP levels, and superoxide anion production by monocytes and polymorphonuclear cells.

The effect of pentoxifylline (Trental) on the phagocytic capacity, cAMP levels, and superoxide anion production of human peripheral blood monocytes and polymorphonuclears (PMNs) was studied. The drug inhibited the phagocytosis of latex particles by both monocytes and PMNs in a dose-dependent manner. In addition, superoxide anion production during the phagocytic process was also reduced following incubation of the cells with pentoxifylline. It is suggested that this inhibitory effect is due to the increased intracellular levels of cAMP induced by the drug.

Cyclic AMP↗
PubMed1986

Short stature as the major manifestation of celiac disease in older children.

Celiac disease was diagnosed by jejunal biopsy and response to gluten elimination in 11 of 23 children with short stature referred after negative endocrine evaluation. The mean age of the group was 11 years, with a range of 5-16. All had been followed for a mean of 2.5 years at a large pediatric endocrine clinic for the evaluation of growth retardation. Bone age retardation of more than 25 percent of the chronologic age was found in all children. Microcytic anemia and past history of gastrointestinal problems were typical of the celiac group but were not documented in the nonceliac patients. Stool fat excretion was a specific but insensitive test, while the 1-hour blood xylose test was of no value in differentiating between the two groups. Close cooperation between pediatric endocrinology and gastroenterology clinics may be fruitful in the identification of celiac patients, especially in a group of older children with short stature, bone age retardation, and microcytic anemia.

Adolescent↗
PubMed1986

The effect of nifedipine on protein synthesis and surface morphology of peripheral blood cells.

Peripheral blood polymorphonuclear cells, lymphocytes, and platelets, incubated with nifedipine, showed a marked dose-dependent inhibition of the cell capacity to synthesize proteins. The possible role of the drug as a Ca2+ blocker for the explanation of this finding is discussed. In addition, the drug induced surface alterations in all three cell types, the most prominent being observed on the platelets which showed elongation of their pseudopodia. This phenomenon, accompanied by an increase in the negative membranal electric charge, may explain the previously reported inhibition of platelet aggregation caused by nifedipine.

Blood Platelets↗
PubMed1985

Postnatal development of hepatic bile formation in the rabbit.

To investigate postnatal maturation of hepatic bile formation, bile output was measured in four groups of rabbits: suckling infants at ages 10-14, 18-22, and 26-30 days, and adults. Bile output was collected directly from the common duct during three 1-hr periods: a basal period followed by intravenous infusion of 1 and then 2 mumol/min/kg of glycodeoxycholic acid. [14C]Erythritol and [3H]inulin clearances measured canalicular bile flow and biliary permeability. Under basal conditions and with the exogenous bile acid, bile flow and bile salt secretion were lowest in 10- to 14-day-old infants and showed a gradual increase with increasing age. Bile salt-dependent flow, the linear increase in flow relative to bile salt secretion, was higher in the 10- to 14- and 17- to 22-day-old compared to the adult and 25- to 30-day-old groups. The ratio of chloride to bile salt secreted was also higher in the two younger groups. Bile salt-independent flow at theoretical zero bile salt secretion was absent in the younger groups, but evident in the adult and 25- to 30-day-old rabbits. Canalicular flow estimated by erythritol clearance was linearly related to bile salt secretion. Inulin clearance relative to erythritol clearance was higher in the 10- to 14-day-old infants than the adults. Thus, bile flow and bile salt secretion are reduced in the young infant but rise to near adult levels at the time of weaning, 25-30 days in the rabbit. The increase in flow results from increased bile salt secretion and the appearance of bile salt-independent flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1985

Naloxone is protective against indomethacin-induced intestinal ulceration in the rat.

Naloxone, an opiate antagonist, was reported to protect against stress ulcers in dogs and rats. We studied its possible protective effect against indomethacin-induced intestinal ulceration in the rat. Naloxone was indeed found to possess a marked protective effect on the intestinal mucosa (ulcer index 73.3 +/- 13.6 vs. 273.8 +/- 21.8, p less than 0.001). Naloxone was found to elevate basal intestinal mucosal prostaglandin E2 (p less than 0.001) and cyclic adenosine monophosphate levels (p less than 0.005) but was unable to overcome the inhibition of prostaglandin E2 caused by indomethacin. An increase of cyclic adenosine monophosphate levels was seen, however, even in the presence of indomethacin, suggesting that cyclic adenosine monophosphate, but not prostaglandins, may play a role in the protective effect of naloxone.

Animals↗
PubMed1985

Reduced bile output with chronic enteral and parenteral infusion of amino acids, glucose, and fat emulsion in rabbits.

To assess the effect of chronic administration of amino acids, glucose, and fat on hepatic excretory function, bile flow and bile salt secretion were directly measured in adult rabbits alimented either intravenously or intragastrically. Five groups of animals were studied after 9-11 days on different nutritional regimes: the first, controls, received 154 mM NaCl intravenously and rabbit chow ad libitum; the second, 2.5% amino acid-10% glucose-10% fat emulsion intravenously; the third, the same nutrients intragastrically; the fourth, reduced intake of rabbit chow to match the weight change in the intragastrically fed animals; the fifth was allowed rabbit chow ad libitum and then received the nutrient solutions intragastrically only during bile collection. Bile was collected directly at laparotomy from the common bile duct during three 1-h periods: a basal period when no exogenous bile salt was infused, then with the addition of 1, and finally 2 mumol/min/kg of glycodeoxycholic acid, the main bile acid of rabbits. During the 3-h experiment either saline (control) or the nutrient solution was administered by the respective route. Chronic administration of the nutrient solutions, whether intravenously or intragastrically, significantly (p less than 0.05) reduced bile flow and bile salt secretion compared with controls and the rabbits on a reduced chow intake. The chronic intravenous route had a more pronounced cholestatic effect than the intragastric route. Acute intragastric nutrient infusion had no effect. The decreased bile output in the chronic groups resulted from a reduction in both bile salt secretion and bile salt-independent flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1985

Effect of epidermal growth factor on ontogeny of the gastrointestinal tract.

The effect of epidermal growth factor (EGF) on the ontogeny of the gastrointestinal tract was examined in New Zealand White rabbits. EGF, 40 micrograms X kg-1 X day-1, was administered to suckling animals from 3-18 days of age either intraperitoneally or orogastrically. Controls received saline. Animals were killed at 17-18 days of age. Body weight and wet weight of stomach, pancreas, and 10-cm segments of proximal, mid, and distal small intestine were measured. The total pancreas was homogenized for determination of protein, DNA, and amylase, and the intestinal mucosa was scraped, weighed, and homogenized for estimation of protein, DNA, sucrase, and lactase. While body weights were similar wet weight of stomach and pancreas were increased by intraperitoneal and orogastric EGF. Small intestinal wet weights were increased in all segments by intraperitoneal but not orogastric EGF, and both routes significantly increased mucosal DNA in the distal segment. EGF administered orogastrically induced precocious maturation of intestinal brush-border disaccharidase activities but had no effect on pancreatic amylase, whereas EGF administered intraperitoneally induced precocious maturation of pancreatic amylase but had no effect on brush-border disaccharidase activities. These findings suggest that both systemic and oral EGF play a role in regulating growth and postnatal maturation of the gastrointestinal tract.

Amylases↗
PubMed1985

Platelet X-ray microanalysis in patients with chronic renal failure.

The platelet element content was determined by semiquantitative X-ray microanalysis in 6 patients with chronic renal failure. The patients showed a different degree of thrombocytopathy expressed by impaired adhesiveness, epinephrine-induced aggregation and platelet factor 3 availability. The microanalysis indicated significantly increased quantities of phosphorus and copper in patients' platelets. Sodium and zinc showed a decrease in about half of the patients, whereas iron was significantly increased in at least 50% of the patients. Magnesium and potassium did not show any difference from the control. The results of sulfur, chlorine and calcium did not reveal a consistent pattern.

Arachidonic Acid↗
PubMed1985

Protein conservation by the immature intestine.

Uptake of intact macromolecules by the immature gut is a well-known phenomenon, but no information exists on the possibility that there is also increased protein loss in the intestinal lumen in preterm infants. We determined alpha-1-antitrypsin (A-1-AT) levels in fecal samples from 39 infants born after 27-41 weeks of gestation from birth up to 30 days of age. A-1-AT levels were elevated only in meconial stools, and low in nonmeconial stools, regardless of associated respiratory disorders, drug administration, and type of nutrition. This study shows that the immature gut has a mature pattern of protein conservation at least as early as after 29 weeks of gestation.

Feces↗
PubMed1985

Total parenteral nutrition-associated cholestasis: acute studies in infant and adult rabbits.

To assess the basis of cholestasis associated with total parenteral nutrition (TPN), we studied the short-term effect of the component solutions on bile flow and bile salt secretion in infant and adult rabbits. Groups of four to six adult and infant rabbits received intravenously 154 mM NaCl (control), 2.5% amino acid, 10% glucose, or 10% fat emulsion alone or in combination. Bile was collected directly from the common bile duct for 3 h. Solutions containing both amino acids and glucose significantly (p less than 0.05) reduced bile flow and bile salt secretion in both age groups. Glucose alone also decreased bile flow and bile salt secretion, whereas amino acids as the sole infusate significantly (p less than 0.05) decreased bile flow only. The suppressive effect of the amino acid-glucose solutions on bile flow was more pronounced in infants than in adults. Fat emulsion alone had no effect on bile formation. Our findings demonstrate that short-term intravenous administration of nutrient solutions containing amino acids and glucose reduces bile flow and bile salt secretion, suggesting that these components are responsible for TPN-associated cholestasis.

Age Factors↗