Search PubMed⌕ Search

Biomedical subjects

A Livne

Publications and source records attributed to A Livne.

At least 19 recordsLinked to original sources
PubMed2001

Identification and localization of a thylakoid-bound carbonic anhydrase from the green algae Tetraedron minimum (Chlorophyta) and Chlamydomonas noctigama (Chlorophyta).

In order to broaden our understanding of the eukaryotic CO2-concentrating mechanism the occurrence and localization of a thylakoid-associated carbonic anhydrase (EC 4.2.1.1) were studied in the green algae Tetraedron minimum and Chlamydomonas noctigama. Both algae induce a CO2-concentrating mechanism when grown under limiting CO2 conditions. Using mass-spectrometric measurements of 18O exchange from doubly labelled CO2, the presence of a thylakoid-associated carbonic anhydrase was confirmed for both species. From purified thylakoid membranes, photosystem I (PSI), photosystem II (PSII) and the light-harvesting complex of the photosynthetic apparatus were isolated by mild detergent gel. The protein fractions were identified by 77 K fluorescence spectroscopy and immunological studies. A polypeptide was found to immunoreact with an antibody raised against thylakoid carbonic anhydrase (CAH3) from Chlamydomonas reinhardtii. It was found that this polypeptide was mainly associated with PSII, although a certain proportion was also connected to light harvesting complex II. This was confirmed by activity measurements of carbonic anhydrase in isolated bands extracted from the mild detergent gel. The thylakoid carbonic anhydrase isolated from T. minimum had an isoelectric point between 5.4 and 4.8. Together the results are consistent with the hypothesis that thylakoid carbonic anhydrase resides within the lumen where it is associated with the PSII complex.

Animals↗
PubMed2001

Haemophilus influenza type b vaccine in Israel: experience in a paediatric ambulatory clinic.

In Israel, vaccination are the overall responsibility of the government. We were the first in Israel to give the Hib (Haemophilus influenza type b) vaccine to the population, through independent means, without government control. The aim of the study was to follow longitudinally the specific group of children vaccinated in our ambulatory clinic. In this study, 1,497 children between 2 and 52 [mean (SD) 13 (9)] months of age at the time of first vaccination were vaccinated with Hib vaccine. Over the next 7 years, they were followed up by repeated phone calls when parents were asked about hospitalisation and any serious infectious diseases. Of the 1,497, 1,444 were followed during the years 1992 to 1999 and 36 were hospitalised during this time. All blood and cerebrospinal fluid cultures were negative. No proven case of Hib infection could be demonstrated. Despite the small sample size, this study justifies the continued use of the vaccine along with maintaining surveillance for Hib infection.

Age Distribution↗
PubMed2001

Caspase activation by adenovirus e4orf4 protein is cell line specific and Is mediated by the death receptor pathway.

Adenovirus E4orf4 protein has been shown to induce transformed cell-specific, protein phosphatase 2A-dependent, and p53-independent apoptosis. It has been further reported that the E4orf4 apoptotic pathway is caspase-independent in CHO cells. Here, we show that E4orf4 induces caspase activation in the human cell lines H1299 and 293T. Caspase activation is required for apoptosis in 293T cells, but not in H1299 cells. Dominant negative mutants of caspase-8 and the death receptor adapter protein FADD/MORT1 inhibit E4orf4-induced apoptosis in 293T cells, suggesting that E4orf4 activates the death receptor pathway. Cytochrome c is released into the cytosol in E4orf4-expressing cells, but caspase-9 is not required for induction of apoptosis. Furthermore, E4orf4 induces accumulation of reactive oxygen species (ROS) in a caspase-8- and FADD/MORT1-dependent manner, and inhibition of ROS generation by 4,5-dihydroxy-1, 3-benzene-disulfonic acid (Tiron) inhibits E4orf4-induced apoptosis. Thus, our results demonstrate that E4orf4 engages the death receptor pathway to generate at least part of the molecular events required for E4orf4-induced apoptosis.

Adenoviridae↗
PubMed2000

The efficacy of oral deferiprone in acute iron poisoning.

Due to its high cost and need for parenteral administration, the standard iron chelator deferoxamine is not used in many individuals with acute and chronic iron poisoning worldwide. Deferiprone is the first oral iron chelator to be shown to be effective in chronically iron overloaded thalassemia patients. Its efficacy, by oral administration, in acute iron poisoning has not been tested. Our objective was to determine whether orally administered deferiprone can reduce the mortality of rats following acute, toxic, oral doses of iron. Rats were administered 612 mg/kg elemental iron orally, corresponding to LD50 in the species tested. Two other groups received the same oral dose of iron followed by oral deferiprone: 800 mg/kg and 800 mg/kg, followed by another dose of 800 mg/kg 2 hours later. Coadministration of 800 mg/kg deferiprone with the iron decreased mortality from 30% to 6.6% after 2 hours (P = .02), from 40% to 16.6% after 12 hours (P = .04), and from 53.3% to 20% after 24 hours (P = 0.007). Mortality was also significantly decreased among animals coadministrated 2 repeated doses of deferiprone of 800 mg/kg with iron, to 0%, 9%, and 18%, and 2, 12, and 24 hours postdrug administration, respectively (P = .04, .05, .04, respectively). Histologically, there was a dose-dependent decrease in iron accumulation in the gastrointestinal tract. Orally administered deferiprone can decrease morbidity and mortality caused by acute iron overdose in rats. Oral deferiprone holds promise in the treatment of iron poisoning in humans.

Acute Disease↗
PubMed2000

Imaging after urinary tract infection in male neonates.

OBJECTIVE: To assess the frequency of urinary tract anomalies in male neonates <8 weeks old who presented with urinary tract infection (UTI), and to evaluate a suitable imaging approach after the initial infection. DESIGN: During a period of 4.5 years, from July 1994 through December 1998, 45 male neonates <8 weeks old (range: 5-56 days; mean: 23.77 days) with UTI were hospitalized. All patients had an ultrasound (US) and a voiding cystourethrogram (VCUG), except 1 neonate in whom VCUG was unsuccessful because of technical problems. A dimercaptosuccinic acid (DMSA) scan was recommended to all patients but was performed only in 30 of 45, most of them with an abnormal VCUG. The renal scan was performed at least 4 months after the UTI. RESULTS: Urinary tract abnormalities were observed in 22 of 45 male neonates. Nineteen had vesicoureteral reflux (VUR), 1 had VUR and a double collecting system, 1 had VUR and a posterior urethral valve, and 1 had an ureteropelvic junction stricture. Renal atrophy or scars, as demonstrated by DMSA scan, were detected almost exclusively in neonates with VUR grade 3 and above. Only 1 neonate with VUR grade 1 had a pathologic DMSA, and the US of this male also demonstrated renal atrophy. Escherichia coli was the pathogen in 62% (28 of 45), and 9 boys had bacteremia. CONCLUSION: We suggest that US and VCUG should be performed routinely after the initial UTI in male neonates. Renal scan should be reserved for those cases in which the US suggests renal parenchymal damage or when VCUG detects VUR grade 3 and above.

Chelating Agents↗
PubMed1999

[Familial hemiplegic migraine of childhood].

Familial hemiplegic migraine is a rare autosomal, dominant, migraine subtype. It is characterized by acute episodes of hemiplegia and hemisensory deficits, and other neurological abnormalities occurring either before or together with severe headache, nausea and vomiting; episodes last several hours and then spontaneously subside. Intervals between episodes are relatively prolonged. Unless there is a relevant family history suggesting this syndrome, the diagnosis is usually delayed. Recently the gene for the syndrome was identified on chromosome 19. We report 3 boys and 1 girl, 11-15 years old with hemiplegic migraine.

Adolescent↗
PubMed1997

Acute iron intoxication: significant differences between sexes.

Iron, one of the common medications in use among children and adults, is the leading cause of pediatric unintentional ingestion fatalities and is not an uncommon poisoning among adults. Accidental ingestion is common because iron-containing compounds are readily available, brightly colored, often sugar coated, and frequently considered harmless vitamins. There are no data on differences between sexes with regard to iron intoxication, and the management of iron overdose is the same for females and males. After oral administration by gavage of the LD50 of iron to Wistar rats, the pharmacokinetics of iron, baseline and peak serum iron levels, and mortality rates were compared between sexes. Prepubertal females died significantly more than males (p < 0.01), pubertal females died significantly earlier than males (p < 0.04), and the same was true among adult rats (p = 0.02). Baseline serum iron levels were not significantly different between prepubertal female and male rats, but female pubertal rats had significantly higher baseline iron levels than males (p = 0.006). After iron administration, females had significantly higher peak serum iron concentrations (p < 0.03). Mechanisms of iron absorption are still not completely known and, probably, there are differences in iron absorption between sexes, which may account for the differences in serum iron levels and mortality rates. While the therapeutic approach in cases of intoxication is individual, iron intoxication, as may be true for other poisonings also, treatments administered to females may need to be different from that given to males.

Administration, Oral↗
PubMed1994

Peritoneal ventilation: an animal model of extrapulmonary ventilation in experimental adult respiratory distress syndrome.

Adult respiratory distress syndrome (ARDS) is a critical medical problem in which severe arterial hypoxemia is often poorly responsive to conventional modes of mechanical ventilation. We studied the efficiency of mechanical ventilation of the peritoneal cavity in rabbits with experimental ARDS caused by lung lavage. The study shows that peritoneal ventilation is significantly effective in oxygenation of hypoxemic animals with ARDS and is also effective for carbon dioxide elimination. Peritoneal ventilation may be considered as an investigational method for extrapulmonary oxygenation in severe intractable hypoxemia caused by ARDS.

Animals↗
PubMed1991

[Antinuclear antibodies in IgA nephropathy, as well as mesangiocapillary and membranous glomerulonephritis].

IgA nephropathy, assumed to be a form of chronic immune complex glomerulonephritis, has sometimes been associated with various autoimmune diseases and autoimmune phenomena including autoantibody production. The present study was aimed at thoroughly investigating the frequency of autoantibodies against five common nuclear autoantigens in 59 patients with IgA nephropathy and in 48 patients with other immune complex glomerulonephritides (24 patients with membranous and 24 with mesangio-capillary glomerulonephritis) and in 30 healthy controls. The incidence of raised autoantibody titres (greater than or equal to 2 SD of the average of controls) in IgA NP was not found to be significantly different from the incidence of other immune complex glomerulonephritis groups. In none of the subjects was a titer above 3 SD of the average of controls found. Although IgA NP is thought to be an immune mediated disease, on the basis of our study it is not associated with a statistically significant incidence of raised antinuclear antibodies.

Antibodies, Antinuclear↗
PubMed1991

Incorporation of lipids labeled with various fatty acids into the cytoskeleton of aggregating platelets.

Earlier studies showed that during the first 20 to 25 seconds of aggregation induced by thrombin (0.1 U/mL) or adenosine diphosphate (ADP) (2 microM) of rabbit or human platelets prelabeled with [3H]palmitic acid, labeled lipid became associated with the cytoskeleton (isolated after lysis with 1% Triton X-100, 5 mM EGTA [ethylene glycolbis-(beta-aminoethyl ether(N,N,N',N'-tetraacetic acid] in the presence of 0.5 mM leupeptin and 50 mM benzamidine). In comparison with labeled lipid in intact platelets, the labeled lipid that was associated with the cytoskeleton was enriched in phospholipids and ceramide. To determine whether these effects were specific for lipids labeled with palmitic acid, we studied rabbit platelets in which lipids had been labeled by incubation of the platelets with pairs of 14C- or 3H-labeled palmitic, stearic, arachidonic, and linoleic acids. Examination of the distribution of label among the lipid classes of intact platelets showed that phospholipids contained most of the label. Under the conditions of limited, thrombin-induced aggregation used, labeled lipids were not lost from the platelets and the distribution of label among the lipid classes was essentially unchanged. There were major differences in the incorporation of labeled lipids into the cytoskeleton. The greatest incorporation (2.1 to 2.8% of the label in the platelets) was observed with palmitic acid-labeled lipids; by direct comparison, only 44% as much of the label of stearic acid-labeled lipids, 21% as much of the label of linoleic acid-labeled lipids, and only 6% as much of the label of arachidonic acid-labeled lipids was incorporated into the cytoskeleton.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The role of glycolysis and univalent ions in phthalocyanine-sensitized photohaemolysis of human erythrocytes.

Phthalocyanines sensitize human erythrocytes to red light in vitro and in vivo. The mechanism of photosensitization of haemolysis of red blood cells was studied using haemoglobin release in vitro as an endpoint. We have previously shown that the cation present in the incubation medium determines the rate of photohaemolysis, with the rate increasing in the order Li+, Na+, K+, Cs+, Rb+. With halogen anions, the rate increases in the order F-, Cl-, Br-. With F- in isotonic solution the rate was about two orders of magnitude slower than with Cl-, so that haemolysis was practically prevented. Fluoride slowed haemolysis at very low concentrations (less than 1 mM) with an apparent K1 of 0.1 mM in isotonic NaCl. Most of the effect disappeared when F- was added after light exposure, with a half-time of 1 min. The effect of F- was specific to phthalocyanine. Neither Photofrin-induced photohaemolysis nor gramicidin-induced haemolysis were inhibited by fluoride. Addition of 10 mM deoxyglucose prior to photosensitization enhanced haemolysis and reduced cellular ATP levels by about 50% compared to controls containing glucose. Haemolysis was preceded by a reduction in ATP levels in the presence of both glucose and deoxyglucose. No significant decrease in ATP levels was found following light exposure in the presence of 0.75 mM F-. It is concluded that glycolysis and ATP are important in preventing photohaemolysis. The protective effect of F- may be related to its inhibition of a fast early reaction which triggers the events leading to photohaemolysis induced by phthalcyanine.

Anions↗
PubMed1990

Cytoplasmic acidification and activation of Na+/H+ exchange during regulatory volume decrease in Ehrlich ascites tumor cells.

Ehrlich ascites tumor cells undergoing regulatory volume decrease (RVD) exhibit cytoplasmic acidification as measured by an intracellular fluorescent pH indicator. The acidification results in an activation of the Na+/H+ exchanger. The intracellular pH 'set point' for the activation is estimated to be around 7.0. The activation of the Na+H+ exchanger leads to an incomplete RVD. In support of this conclusion, amiloride and Na+-free medium, known to limit the Na+/H+ exchange, indeed enhance the RVD response. Intracellular acidification and activation of Na+/H+ exchange may be a general response of cells undergoing RVD.

Amiloride↗
PubMed1990

Palmitic acid-labeled lipids selectively incorporated into platelet cytoskeleton during aggregation.

Previous experiments showed that during the early stages (20-30 seconds) of aggregation induced by adenosine diphosphate (ADP, 2 microM) or thrombin (0.1 U/mL) of rabbit or human platelets prelabeled with [3H]palmitic acid, labeled lipid became associated with the cytoskeleton isolated after lysis with 1% Triton X-100, 5 mM EGTA [ethylene glycol-bis-(beta-aminoethyl ether)]-N,N,N',N'-tetra-acetic acid. The association appeared to be related to the number of sites of contact and was independent of the release of granule contents. We have now investigated the nature of the labeled lipids by thin-layer and column chromatography and found differences between the distribution of the label in intact platelets (both stimulated and unstimulated) and the isolated cytoskeletons. In both species, and with either ADP or thrombin as aggregating agent, 70-85% of the label in both intact platelets and in the cytoskeletons was in phospholipids. The distribution of label among the phospholipids in the cytoskeletons was similar to that in intact platelets except that the percentage of label in phosphatidylcholine was significantly higher in the cytoskeletons of human platelets than in the intact platelets, and the percentage of label in phosphatidylserine/phosphatidylinositol was significantly lower in the cytoskeletons of rabbit platelets and thrombin-aggregated human platelets than in intact platelets. The cytoskeletons contained a lower percentage of label in triacylglycerol, diacylglycerol, and cholesterol ester than the intact platelets. Contrary to a report in the literature, we found no evidence for the incorporation of diacylglycerol and palmitic acid into the cytoskeleton.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗