PubMed Health⌕ Search

Biomedical subjects

H Levy

Publications and source records attributed to H Levy.

At least 19 recordsLinked to original sources
PubMed1992

Regulation and light-harvesting complex II association of a Dunaliella protein homologous to early light-induced proteins in higher plants.

The unicellular green alga Dunaliella bardawil responds to high light, nutrient deprivation, and several other types of stress by massive accumulation of beta-carotene. We have previously cloned a nuclear gene, cbr, that is co-induced with accelerated carotenogenesis. The predicted product of cbr is closely related to early light-induced proteins (Elips) of higher plants, and also shows resemblance to chlorophyll a/b-binding proteins. In the present study, the determination of the cbr transcription start site supported the previously proposed site of translation initiation. Antibodies raised against a synthetic oligopeptide matching the predicted sequence of Cbr recognized two polypeptides of apparently 17 and 19 kDa that were induced in parallel to cbr transcript accumulation in highly illuminated or sulfate-starved D. bardawil cells. The antibodies also cross-reacted with an approximately 20-kDa polypeptide in sulfate-starved Dunaliella salina. In both D. bardawil and D. salina, Cbr was found exclusively in the thylakoid membranes. After mild solubilization, Cbr co-fractionated with light-harvesting complex II (LHCII) in sucrose gradient centrifugation and gel electrophoresis and was specifically associated with a minor LHCII complex. An occasionally observed, faster mobility Cbr form, free of LHCII, was probably released from the larger complex. These results support the conclusion that Cbr belongs to a class of stress-induced proteins transiently associated with antennae complexes.

Amino Acid Sequence↗
PubMed1992

The value of bronchoalveolar lavage and bronchial washings in the diagnosis of invasive pulmonary aspergillosis.

The objective of this study was to clarify conflicting reports of the sensitivity and specificity of bronchoalveolar lavage or bronchial washings for diagnosing invasive pulmonary aspergillosis. The study was a retrospective review of 300 consecutive patients in a tertiary referral centre subjected to 343 fiberoptic bronchoscopic procedures for the evaluation of pulmonary infiltrates. Classification of paired fungal culture and cytologic examination of bronchoalveolar lavage or bronchial washing fluid according to clinical, radiographic, histological and autopsy evidence of invasive pulmonary aspergillosis. One-hundred and fifteen deaths occurred, with a 58% autopsy rate. A diagnosis of invasive pulmonary aspergillosis was made in 21 immunosuppressed patients with 16 deaths. Bronchoalveolar lavage cytology showed aspergillus in 19 specimens (invasive pulmonary aspergillosis in 16), cultures yielded aspergillus in 41 (invasive pulmonary aspergillosis in ten), with both tests positive in nine. Cytology sensitivity was 64.0%, specificity 99.1%, positive predictive value 84.2%, and negative predictive value 97.2%. Culture sensitivity was 40.0%, specificity 90.3%, positive predictive value 24.4%, and negative predictive value 95.0%. Concordant cytology and culture sensitivity was 32.0%, specificity 99.7%, positive predictive value 88.9%, and negative predictive value 94.9%. In conclusion, when characteristic hyphae are visualized in bronchoalveolar lavage specimens from immunosuppressed patients with compatible clinical data, it is advisable to treat for presumptive invasive pulmonary aspergillosis.

Adult↗
PubMed1991

Co-regulation of a gene homologous to early light-induced genes in higher plants and beta-carotene biosynthesis in the alga Dunaliella bardawil.

Dunaliella bardawil, a unicellular green alga that can be induced to accumulate massive amounts of beta-carotene, is particularly suitable for studies of carotenogenesis regulation and its links to developmental and adaptive processes in the chloroplast. A cDNA clone corresponding to a transcript accumulating coordinately with carotenogenesis induction was isolated by differential hybridization of a cDNA library made from intensely illuminated cells. This transcript was also abundant in algal mutants able to accumulate beta-carotene under relatively low light intensity. DNA sequence analysis indicates that cbr (for carotene biosynthesis-related) is closely related to early light-induced genes (elip) of higher plants. Similarity also exists between repeated oligopeptide motifs in Cbr and Cab proteins of photosystems I and II. Three upstream direct repeats in cbr include an octamer and hexamer related to mammalian sterol regulatory elements. The relationship between cbr transcript and beta-carotene accumulation, the structural similarity between Cbr and Cab proteins, and the presence of potential SRE-1 elements lead us to propose that Cbr represents novel carotenoid binding proteins, whose synthesis might be coordinated with carotenogenic enzymes via an evolutionary conserved regulatory mechanism.

Amino Acid Sequence↗
PubMed1991

Identification of viral proteins encoded by two DNA fragments of herpesvirus of turkeys (HVT).

Herpesvirus of turkeys (HVT) vaccine is used worldwide to immunize chickens against Marek's disease (MD). Polyclonal antiserum directed against one virus cross-reacts with proteins of the other, while only 5% homology at the DNA level was demonstrated between the two viruses. A partial library of HVT DNA fragments ranging from 1.5 to 13.5 kbp in size was constructed in pBR 322. Under stringent conditions of hybridization (low salt concentration, 10% dextran sulfate at 68 degrees C), two of the cloned HVT DNA fragments (13.5 and 11.0 kbp) hybridized to three MDV DNA fragments: BamHI-C, D, and G. The 13.5 kbp fragment detected two transcripts of 1.8 and 3.0 kb in RNA extracted from HVT-infected chicken embryo fibroblasts, while the 11.0 kbp fragment detected three transcripts of 1.6, 2.0, and 3.0 kb in the extracted RNA. Using hybrid selection, specific RNA was isolated by hybridization with the two cloned HVT DNA fragments and then was translated in vitro using rabbit reticulocyte lysate, and the resulting proteins were analyzed by NaDodSO4-PAGE. The RNA selected by the two HVT DNA fragments coded for a 30 kD protein and for several smaller proteins 10-20 kD in size, while the RNA selected by the 11.0 kb HVT DNA fragment was translated into a 40 kD protein. Immunoprecipitation of these in vitro synthesized proteins with hyperimmune anti-HVT chicken serum showed that they were of viral origin.

Animals↗
PubMed1991

Molecular aspects of Gaucher disease.

Gaucher disease is the most common sphingolipid storage disorder. Due to its high prevalence it may appear with a nonrelated neurological disease and be misinterpreted as Gaucher type 3. A family is described in which 2 Gaucher brothers presented different clinical signs. Molecular analysis has shown that both carried two mutated alleles. One allele had a G to C transversion at nucleotide 3119 of the active gene (Asp140-His) while the other presented two base pair changes, an A to C transversion at nucleotide number 3170 (Lys157-Gly), and a G-A transition at nucleotide number 5309 (Glu324-Lys). Therefore, both presented the same type of Gaucher disease which was accompanied with a nonrelated neurological disease in one of them. Molecular diagnosis of 161 patients has provided a relative abundance of different mutations among Jewish and non-Jewish patients and allowed some genotype-phenotype correlation. Differential expression of the murine glucocerebrosidase activator gene (the prosaposine) has been demonstrated using Northern technique and in situ hybridization. High expression levels were observed in the brain and testes. In the testes the prosaposine expression was confined to the supporting cells. In the female gonad prosaposine expression has also been shown, in the corpus luteum. In a 12 1/2-day-old embryo, prosaposine gene expression was detected mainly in brain stem, in dorsal ganglia and in the genital ridge.

Adolescent↗
PubMed1991

Comparison of bacteraemic community-acquired lobar pneumonia due to Streptococcus pneumoniae and Klebsiella pneumoniae in an intensive care unit.

In a study of 41 consecutive patients with bacteraemia-associated community-acquired lobar pneumonia due to Streptococcus pneumoniae and Klebsiella pneumoniae an attempt was made to determine whether distinguishing criteria of disease due to these organisms could be identified according to demographic features and the results of initial clinical and laboratory investigations. Such information would aid in the early initiation of appropriate antimicrobial therapy. The most significant difference between the two groups of patients was the lower platelet count in the K. pneumoniae group (p less than 0.005). In addition leucopenia (p less than 0.05), higher serum albumin (p less than 0.05), and the male sex (p less than 0.05) featured with an increased frequency in patients with pulmonary infection due to K. pneumoniae. Initial antimicrobial therapy in critically ill patients with community-acquired lobar pneumonia and thrombocytopenia, particularly when associated with leucopenia and in male patients, should include agents effective against K. pneumoniae.

Adult↗
PubMed1990

A preliminary report of the collaborative study of maternal phenylketonuria in the United States and Canada.

The Maternal Phenylketonuria Collaborative Study (MPKUCS), encompassing all the United States and provinces of Canada, is a prospective, longitudinal investigation designed to ascertain the efficacy of phenylalanine-restricted therapy in protecting the fetus from high maternal phenylalanine concentrations in women with hyperphenylalaninaemia. Preliminary findings are reported for 147 pregnancies for whom the recommended therapeutic range of blood phenylalanine was 120-360 mumols/L. Sixty-three pregnancies had complete data for analysis. Dietary control was attempted prior to conception in 10 out of 63 women. Significant negative correlations were noted in length, weight and head circumference and blood phenylalanine concentrations during pregnancy. Average reported phenylalanine levels by trimester for 63 hyperphenylalaninaemic pregnancies resulting in live births revealed that no group requiring treatment achieved levels below 360 mumols/L until the third trimester. Median birth measurement percentiles revealed that all groups studied generally had smaller head size compared with birth length and weight. Those started on diet after the first trimester achieved a head circumference below the 10th percentile. The implication of small head circumference for subsequent intellectual development is unclear at this time. Furthermore, the study must evaluate more offspring of women having optimal preconception and pregnancy restriction of phenylalanine.

Canada↗
PubMed1990

MR evaluation of renal space-occupying lesions: diagnostic criteria.

In order to assess the ability of magnetic resonance (MR) imaging to distinguish simple renal cysts from renal tumors, images from 53 patients with 74 lesions were reviewed. MR image characteristics, including signal strength and homogeneity for each lesion, were evaluated and compared with the final diagnoses. There were 53 cysts and 21 tumors. For 56 lesions (76%), MR allowed accurate diagnosis; on T1-weighted images, homogeneous low-intensity lesions were always cysts and inhomogeneous medium- or high-intensity lesions were always tumors. The remaining 18 lesions (24%) could not be distinguished, and T2-weighted images failed to improve differential diagnostic ability. In our experience, MR imaging allows differentiation of renal cysts and tumors less frequently than does computed tomography (CT) or ultrasound (US). MR criteria for simple renal cysts and tumors are offered, with the understanding that modification may be necessary as experience with these lesions increases.

Diagnosis, Differential↗
PubMed1990

Klebsiella pneumoniae bacteraemia at an urban general hospital.

Of 47 patients with Klebsiella pneumoniae bacteraemia admitted to the Hillbrow Hospital, Johannesburg during a period of 18 months, 31 were males and 16 were females. Features predisposing to illness were found in 89.4% patients, chronic alcoholism, neoplastic disease and diabetes mellitus being the most common. Twenty-five infections were acquired in hospital and 22 in the community. Most patients (59.6%) had pneumonia. All isolates of K. pneumoniae were resistant to ampicillin (100%); several (42.6%) were resistant to other antibiotics also. The overall mortality rate was 55.3%. A higher mean initial blood pressure and lower concentrations of serum urea and bilirubin were found in survivors. None of the 28 patients, surviving more than 48 h who received combined therapy with an aminoglycoside and a beta-lactam antibiotic (to which the organism was susceptible) died. Among the remaining patients treated with either an appropriate beta-lactam agent alone, an appropriate aminoglycoside alone or ciprofloxacin the combined mortality rate was 83.3% (P = 0.007).

Adolescent↗
PubMed1990

Cryptogenic fibrosing alveolitis. A study of an indigenous African population.

Cryptogenic fibrosing alveolitis (CFA) has not been described previously in any large group of indigenous African patients. This was a retrospective study of 46 such patients diagnosed as having CFA during a 73-month period. The clinical spectrum of illness was similar to that of other groups studied worldwide. Cigarette smoking was associated with a poorer outcome and is a potentially preventable cause of deterioration.

Adrenal Cortex Hormones↗
PubMed1990

Antimycobacterial antibody levels in pleural fluid as reflection of passive diffusion from serum.

The objective of this study was the prospective evaluation of the relationship between serum and pleural fluid antibody levels to mycobacterial antigens and their role in the diagnosis of tuberculous pleuritis. The setting was a tertiary care medical center. Thirteen patients with tuberculous pleuritis and 53 control subjects with pleural effusion (22 with carcinoma, 17 with cardiac failure, and 14 with empyema or parapneumonic effusion) were studied. The level of IgG was measured by ELISA. The median titers of antibody to both Mycobacterium tuberculosis and M avium were significantly higher in the serum and pleural fluid of the patients with tuberculosis than in the control patients. There was a very close relationship between the levels of M tuberculosis (r = 0.95) and M avium (r = 0.94) antibodies in the serum and pleural fluid. We concluded that the levels of antimycobacterial IgG in pleural fluid, adjusted to constant protein concentration, are very closely related to the serum levels. Therefore, these antibodies in the pleural fluid probably result from passive diffusion from serum and not local production. Measurement of pleural fluid antibody levels will not add diagnostic sensitivity or specificity to that achieved with serodiagnosis.

Antibodies, Bacterial↗
PubMed1989

Initial hormonal and metabolic profile in critically ill patients with community-acquired lobar pneumonia.

A prospective study of 18 critically ill patients with community-acquired lobar pneumonia was undertaken at Hillbrow Hospital, Johannesburg, in order to document the initial plasma hormonal and substrate profile as part of the stress response to the infection. The results of these studies, carried out before therapy, were compared with the results in a group of healthy fasting adults. Highly significant (P less than or equal to 0.005) increases in the mean plasma levels of adrenaline, noradrenaline, human growth hormone, cortisol, glucose and free fatty acids were noted in the study group, with a lesser increase in the prolactin concentration (P less than or equal to 0.01). The levels of dopamine, glucagon, insulin and adrenocorticotrophin did not show any significant change. No significant differences were found in the hormonal profile when comparing survivors with non-survivors. The neuro-endocrine hormonal and metabolic responses in pneumonia appear to be similar to those seen in other stress situations and failure of the initial stress response does not appear to contribute to the mortality of critically ill patients with community-acquired lobar pneumonia.

Adult↗