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Biomedical subjects

H Blau

Publications and source records attributed to H Blau.

52 records · Page 3Linked to original sources
PubMed1983

Human actin genes are single copy for alpha-skeletal and alpha-cardiac actin but multicopy for beta- and gamma-cytoskeletal genes: 3' untranslated regions are isotype specific but are conserved in evolution.

We have constructed isotype-specific subclones from the 3' untranslated regions of alpha-skeletal, alpha-cardiac, beta-cytoskeletal, and gamma-cytoskeletal actin cDNAs. These clones have been used as hybridization probes to assay the number and organization of these actin isotypes in the human genome. Hybridization of these probes to human genomic actin clones (Engel et al., Proc. Natl. Acad. Sci. U.S.A. 78:4674-4678, 1981; Engel et al., Mol. Cell. Biol. 2:674-684, 1982) has allowed the unambiguous assignment of the genomic clones to isotypically defined actin subfamilies. In addition, only one isotype-specific probe hybridizes to each actin-containing gene, with a single exception. This result suggests that the multiple actin genes in the human genome are not closely linked. Genomic DNA blots probed with these subclones under stringent conditions demonstrate that the alpha-skeletal and alpha-cardiac muscle actin genes are single copy, whereas the cytoskeletal actins, beta and gamma, are present in multiple copies in the human genome. Most of the actin genes of other mammals are cytoplasmic as well. These observations have important implications for the evolution of multigene families.

Actins↗
PubMed1983

alpha-skeletal and alpha-cardiac actin genes are coexpressed in adult human skeletal muscle and heart.

We determined the actin isotypes encoded by 30 actin cDNA clones previously isolated from an adult human muscle cDNA library. Using 3' untranslated region probes derived from alpha-skeletal, beta- and gamma-actin cDNAs and from an alpha-cardiac actin genomic clone, we showed that 28 of the cDNAs correspond to alpha-skeletal actin transcripts. Unexpectedly, however, the remaining two cDNA clones proved to derive from alpha-cardiac actin mRNA. Sequence analysis confirmed that the two skeletal muscle alpha-cardiac actin cDNAs are derived from transcripts of the cloned alpha-cardiac actin gene. Direct measurements of actin isotype mRNA expression in human skeletal muscle showed that alpha-cardiac actin mRNA is expressed at 5% the level of alpha-skeletal actin. Furthermore, the alpha-cardiac actin gene expressed in skeletal muscle is the same gene which produces alpha-cardiac actin mRNA in the human heart. Of equal surprise, we found that alpha-skeletal actin mRNA accounts for about half of the total actin mRNA in adult heart. Comparison of total actin mRNA levels in adult skeletal muscle and adult heart revealed that the steady-state levels in skeletal muscle are about twofold greater, per microgram of total cellular RNA, than those in heart. Thus, in skeletal muscle and in heart, both of the sarcomeric actin mRNA isotypes are quite abundant transcripts. We conclude that alpha-skeletal and alpha-cardiac actin genes are coexpressed as an actin pair in human adult striated muscles. Since the smooth-muscle actins (aortic and stomach) and the cytoplasmic actins (beta and gamma) are known to be coexpressed in smooth muscle and nonmuscle cells, respectively, we postulate that coexpression of actin pairs may be a common feature of mammalian actin gene expression in all tissues.

Actins↗
PubMed1983

Isolation and characterization of full-length cDNA clones for human alpha-, beta-, and gamma-actin mRNAs: skeletal but not cytoplasmic actins have an amino-terminal cysteine that is subsequently removed.

cDNA clones encoding three classes of human actins have been isolated and characterized. The first two classes (gamma and beta, cytoplasmic actins) were obtained from a cDNA library constructed from simian virus 40-transformed human fibroblast mRNA, and the third class (alpha, muscle actin) was obtained from a cDNA library constructed from adult human muscle mRNA. A new approach was developed to enrich for full-length cDNAs. The human fibroblast cDNA plasmid library was linearized with restriction enzymes that did not cut the inserts of interest; it was then size-fractionated on gels, and the chimeric molecules of optimal length were selected for retransformation of bacteria. When the resulting clones were screened for actin-coding sequences it was found that some full-length cDNAs were enriched as much as 50- to 100-fold relative to the original frequency of full-length clones in the total library. Two types of clones were distinguished. One of these clones encodes gamma actin and contains 100 base pairs of 5' untranslated region, the entire protein coding region, and the 3' untranslated region. The second class encodes beta actin, and the longest such clone contains 45 base pairs of 5' untranslated region plus the remainder of the mRNA extending to the polyadenylic acid tail. A third class, obtained from the human muscle cDNA library, encodes alpha actin and contains 100 base pairs of 5' untranslated region, the entire coding region, and the 3' untranslated region. Analysis of the DNA sequences of the 5' end of the clones demonstrated that although beta- and gamma-actin genes start with a methionine codon (MET-Asp-Asp-Asp and MET-Glu-Glu-Glu, respectively), the alpha-actin gene starts with a methionine codon followed by a cysteine codon (MET-CYS-Asp-Glu-Asp-Glu). Since no known actin proteins start with a cysteine, it is likely that post-translational removal of cysteine in addition to methionine accompanies alpha-actin synthesis but not beta- and gamma-actin synthesis. This observation has interesting implications both for actin function and actin gene regulation and evolution.

Actins↗
PubMed1983

Studies on human milk macrophages: effect of activation on phagocytosis and secretion of prostaglandin E2 and lysozyme.

Breast milk macrophages cultured in vitro synthesized and secreted increasing amounts of protein, lysozyme, and prostaglandin E2(PGE2) into the extracellular medium. These cells were also shown to actively phagocytose labeled zymosan particles in culture. Morphologic characteristics, phagocytosis, and secretory responses of the macrophages were altered depending on the presence of various stimuli in the culture. Concanavalin A, endotoxin and zymosan particles, but not latex particles, all resulted in an increased PGE2 secretion into the medium. Although total protein synthesis was not altered by any of these stimuli, Concanavalin A and endotoxin resulted in a decreased lysozyme concentration in the extracellular medium. Concanavalin A enhanced, whereas endotoxin and prior phagocytosis of latex particles inhibited phagocytosis of labeled zymosan particles. These findings indicate that phagocytosis and secretions of milk macrophages may be altered depending on the nature of the stimulating agent.

Concanavalin A↗
PubMed1983

Hemispheric routing of tactilely delivered words for dyslexic males.

This investigation sought to determine the effect of delivering unknown spelling words via a tactile modality to the left and right cerebral hemispheres of 10 dyslexic boys of about 14 yr. of age whose vision was occluded during word palpation. More words were learned through either condition of right- and left-hand delivery than control words. Spelling meaningful words when vision is occluded can be accomplished by either hand delivery for older dyslexic boys.

Adolescent↗
PubMed1982

The prenatal ultrasonic diagnosis of urethral obstruction and diverticulum of the urinary bladder.

In a 28 year old gravida 2 para 1 an ultrasonogram at 35 weeks of gestation revealed a huge cystic abdominal tumor in fetus. Postpartum ultrasound, excretory urography and micturating cystourethrography showed a trabeculated bladder with a large diverticulum and hydronephrosis due to a posterior urethral valve. The prenatal diagnosis of this anomaly and immediate surgical intervention prevented additional severe damage in the newborn.

Adult↗
PubMed1981

[Meconium ileus].

Explore the source record for details and available documents.

Child, Preschool↗
PubMed1980

Hyperuricosuria in cystic fibrosis patients treated with pancreatic enzyme supplements. A study of 16 patients in Israel.

Uric acid metabolism was evaluated in 16 Israeli cystic fibrosis patients, all of whom were taking pancreatic enzyme supplements. The findings were compared with those in a recent study of uric acid metabolism in 65 healthy Israeli children. Hyperuricemia of 4.9 +/- 0.2 (SE) mg/dl was found in the cystic fibrosis patients, compared with a normal level of 3.1 +/- 0.2 mg/dl ( P < 0.05). In five patients, 24-h urine collections were assayed and all showed hyperuricosuria. Thirteen patients had high urinary uric acid/creatinine ratios. Hyperuricosuria increased with the age of the patient and when the administered dosage of pancreatic enzyme exceeded 10,000 lipase units/kg body weight. Despite normal levels of serum creatinine and urea, and normal creatinine clearance in the cystic fibrosis patients, risk of future renal damage seems obvious and preventive measures should be considered.

Child↗
PubMedDate not supplied

Cost-benefit analysis of a national screening programme for cystic fibrosis in an Israeli population.

The recently acquired ability to identify 97% of CF carriers in an Israeli Ashkenazi population, prompts an evaluation of a nationwide screening programme. In 1993, the programme would first screen and counsel 9,261 parents, then 396 spouses of carrier parents and finally screen 16.5 fetuses where both parents are carriers. Assuming 92% of screened parents choose abortion of fetus screened positive, 2.33 cases of CF will be prevented in 1993 at a direct cost of $781,000. The $326,000 direct costs of preventing a CF case, exceed the lifetime excess direct costs per case of $297,000. However, benefits of screening also accrue to subsequent pregnancies, resulting in a direct benefit ($14.45 million) to cost ($10.39 million) ratio of 1.39/1 for the period 1993-2032. When benefits and costs resulting from mortality changes, work absences and transport costs are included, the benefit ($15.95 million) to cost ($13.88 million) ratio falls to 1.15/1. Benefit-cost ratios are lower for other ethnic groups in Israel, due to lower carrier rates and lower mutation detection abilities. A CF screening programme will increase the freedom of individuals choice, but should be carried out carefully in order to minimize stigmatization and even discrimination against CF carriers.

Abortion, Eugenic↗
PubMedDate not supplied

The development of the chymotryptic activity during postnatal life using the bentiromide test.

The chymotryptic activity was assessed in 40 newborns and infants age 3-180 days using the NBT-PABA test. Nine newborns were studied serially at different age periods. A group of 18 cystic fibrosis patients and a group of 17 healthy children served as pancreatic insufficient and pancreatic sufficient controls, respectively. The results demonstrate a gradual increase with age of chymotryptic activity, approaching the levels of older children at about 180 days. The newborns who were studied serially demonstrated an individual pattern of increase in their chymotryptic activity. In the first days of life, newborns show low chymotryptic activity similar to that found in cystic fibrosis patients.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Methane production in patients with cystic fibrosis.

Methane production was studied in 28 cystic fibrosis patients aged 3-16 years and in 290 healthy children. The percentages of methane producers in the cystic fibrosis and control groups were 60.7 and 20.6%, respectively. In the patient group there was no difference between methane producers and nonproducers with respect to the degree of malabsorption or the administration of pancreatic supplements or antibiotics. We hypothesize that the high proportion of methane producers in cystic fibrosis patients may be associated with the presence of specific substrate(s) (glycoprotein?) in their intestinal contents. Changes of the intestinal microenvironment may favor the development of a methanogenic flora.

Adolescent↗
PubMedDate not supplied

Pulmonary epithelial cell proliferation in primary culture of alveolar type II cells.

A small subpopulation of pulmonary epithelial cells (PE) proliferates in low-density primary culture of alveolar type II cells and forms colonies of cells that could be passaged for several generations and that in some respects maintain a differentiated phenotype of the alveolar type II cells. At this time it is not known if these cells are some form of progenitor epithelial cells or type II cells that are not fully differentiated in vitro. The proliferation of the PE cells was dependent on serum, alveolar macrophage-conditioned medium, and insulin being included in the culture medium. Under these conditions, approximately 0.5-1.0% of the seeded cells that adhered to the culture dishes were capable of forming colonies. Efficiency of colony formation increased to 5-10% in subsequent passages. PE cells maintained a high level (> 40%) of saturated phosphatidylcholine (PC) as a percentage of total PC throughout the culture period (> 28 days). However, the saturated PC content was not constant throughout the long-term culture period and the subsequent passages (41.3% at 29 days and 37.3% in the 3rd passage). These cells also contained numerous lamellar bodies and were able to bind the Maclura pomifera lectin. PE cells also expressed cytokeratin No. 19, as well as alkaline phosphatase activity, both possible markers for differentiated type II cells. However, PE cell synthesized low levels of Pg (approximately 2%), were squamous, and tended to form multiple strata, unlike the cuboidal type II cells in vivo. The cells did not exhibit immunocytochemically demonstrable surfactant-associated protein A (SP-A). Additional factors and culture requirements may be necessary for complete maturation of cultured PE cells. This was demonstrated by culturing PE cells on EHS matrix. Aggregates of cells surrounding a central lumen were formed after a few hours in culture and were maintained for 20 days. The cells contained lamellar bodies and some intercellular junctions. PE cells can be regarded as a highly selected subpopulation of pulmonary epithelial cells that concomitantly maintain proliferation and aspects of differentiated alveolar type II cells in long-term culture.

Animals↗