Biomedical subjects

J Adelman

Publications and source records attributed to J Adelman.

52 records · Page 3Linked to original sources

PubMed2000

Mice deficient in Six5 develop cataracts: implications for myotonic dystrophy.

Expansion of a CTG trinucleotide repeat in the 3' UTR of the gene DMPK at the DM1 locus on chromosome 19 causes myotonic dystrophy, a dominantly inherited disease characterized by skeletal muscle dystrophy and myotonia, cataracts and cardiac conduction defects. Targeted deletion of Dm15, the mouse orthologue of human DMPK, produced mice with a mild myopathy and cardiac conduction abnormalities, but without other features of myotonic dystrophy, such as myotonia and cataracts. We, and others, have demonstrated that repeat expansion decreases expression of the adjacent gene SIX5 (refs 7,8), which encodes a homeodomain transcription factor. To determine whether SIX5 deficiency contributes to the myotonic dystrophy phenotype, we disrupted mouse Six5 by replacing the first exon with a beta-galactosidase reporter. Six5-mutant mice showed reporter expression in multiple tissues, including the developing lens. Homozygous mutant mice had no apparent abnormalities of skeletal muscle function, but developed lenticular opacities at a higher rate than controls. Our results suggest that SIX5 deficiency contributes to the cataract phenotype in myotonic dystrophy, and that myotonic dystrophy represents a multigenic disorder.

3' Untranslated Regions↗

PubMed1999

Differentiation induction subtraction hybridization (DISH): a strategy for cloning genes displaying differential expression during growth arrest and terminal differentiation.

Human cancers often display aberrant patterns of differentiation. By appropriate chemical manipulation, specific human cancers, such as human melanoma, leukemia and neuroblastoma, can be induced to lose growth potential irreversibly and terminally differentiate. Treatment of HO-1 human melanoma cells with a combination of recombinant human fibroblast interferon (IFN-beta) and the antileukemic compound mezerein (MEZ) results in irreversible growth arrest, a suppression in tumorigenic properties and terminal cell differentiation. A potential mechanism underlying these profound changes in cancer cell physiology is the activation of genes that can suppress the cancer phenotype and/or the inactivation of genes that promote the cancer state. To define the repertoire of genes modulated as a consequence of induction of growth arrest and terminal differentiation in human melanoma cells, we are using a differentiation induction subtraction hybridization (DISH) approach. A subtracted cDNA library, differentiation inducer treated cDNAs minus uninduced cDNAs, was constructed that uses temporally spaced mRNAs isolated from HO-1 cells treated with IFN-beta+MEZ. Approximately 400 random clones were isolated from the subtracted DISH library and analyzed by reverse Northern and Northern blotting approaches. These strategies resulted in the identification and cloning of both 30 known and 26 novel cDNAs displaying elevated expression in human melanoma cells induced to growth arrest and terminally differentiate by treatment with IFN-beta+MEZ. The DISH scheme and the genes presently identified using this approach should provide a framework for delineating the molecular basis of growth regulation, expression of the transformed phenotype and differentiation in melanoma and other cancers.

Antineoplastic Agents↗

PubMed1999

Identification and temporal expression pattern of genes modulated during irreversible growth arrest and terminal differentiation in human melanoma cells.

Abnormalities in differentiation are common occurrences in human cancers. Treatment of human melanoma cells with the combination of recombinant human fibroblast interferon (IFN-beta) and the antileukemic compound mezerein (MEZ) results in a loss of tumorigenic potential that correlates with an irreversible suppression in proliferative ability and induction of terminal differentiation. It is hypothesized that this is associated with the differential expression of genes that may directly regulate cancer cell growth and differentiation. To define the relevant gene expression changes that correlate with and potentially control these important cellular processes a differentiation induction subtraction hybridization (DISH) scheme is being used. A temporally spaced subtracted differentiation inducer treated (TSS) cDNA library was constructed and differentially expressed DISH clones were isolated and evaluated using a high throughput microchip cDNA (Synteni) array screening approach. Verification of differential gene expression for specific cDNAs was confirmed by Northern blotting. The temporal kinetics of regulation and the expression pattern of DISH genes were also evaluated by microchip cDNA array screening. Using this approach with 1000 DISH cDNA clones (approximately 10% of the DISH library) has resulted in the identification and cloning of both 26 known and 11 novel cDNAs of potential relevance to growth control and terminal differentiation in human melanoma cells.

Cell Differentiation↗

PubMed1996

Examination of steroid-induced changes in LHRH gene transcription using 33P-and 35S-labeled probes specific for intron 2.

We previously demonstrated that estrogen, but not progesterone, induces a increase in LHRH messenger RNA levels between 0800 and 1200 h in numerous of the rostral preoptic area/organum vasculosum of the lamina terminalis (rPOA/OVLT). To determine whether these changes are a result of increased transcription, we used in situ hybridization histochemistry to examine the temporal effects of estradiol (E2) and progesterone on cellular levels of intron-2-containing LHRH heteronuclear RNA transcripts. To make our method sufficiently sensitive to detect changes in these levels, we used 33P/35S probes to minimize both background and grain stacking over labeled cell nuclei. We found that levels of LHRH heteronuclear RNA rose between 0800 and 1000 in OVX, E2-treated rats, remained elevated at 1200 h, and declined by 1400 h. Progesterone did not affect these E2-induced changes. Our results suggest that an E2-dependent signal initiates LHRH gene transcription in neurons of the rPOA/OVLT hours before LHRH release begins and that progesterone does not affect this signal.

Animals↗

PubMed1995

Characterization and variation of a human inwardly-rectifying-K-channel gene (KCNJ6): a putative ATP-sensitive K-channel subunit.

The ATP-sensitive K-channel plays a central role in insulin release from pancreatic beta-cells. We report here the cloning of the gene (KCNJ6) encoding a putative subunit of a human ATP-sensitive K-channel expressed in brain and beta-cells, and characterisation of its exon-intron structure. Screening of a somatic cell mapping panel and fluorescent in situ hybridization place the gene on chromosome 21 (21q22.1-22.2). Analysis of single-stranded conformational polymorphisms revealed the presence of two silent polymorphisms (Pro-149: CCG-CCA and Asp-328: GAC-GAT) with similar frequencies in normal and non-insulin-dependent diabetic patients.

Adenosine Triphosphate↗

PubMed1995

No evidence for mutations in a putative beta-cell ATP-sensitive K+ channel subunit in MODY, NIDDM, or GDM.

The beta-cell ATP-sensitive K+ (K-ATP) channel has a major role in glucose-induced insulin secretion. Screening the entire coding sequence of the gene for a putative beta-cell K-ATP channel subunit, K-ATP2, with single-strand conformation polymorphism did not show any mutations associated with diabetes in white Caucasian diabetic patients, including five pedigrees with maturity onset diabetes of the young (MODY), 25 patients with noninsulin-dependent diabetes mellitus (NIDDM) selected for marked beta-cell deficiency, 25 selected for mild diabetes presenting before age 50 years with fasting plasma glucose levels < 10 mmol/l, 25 unselected NIDDM patients, and 25 subjects with gestational diabetes mellitus (GDM) and subsequent raised fasting plasma glucose. In five large MODY pedigrees, linkage analysis with simple tandem-repeat polymorphisms (STRPs) near the K-ATP2 gene excluded linkage. In a population association study, no linkage disequilibrium for the STRP was found between 237 unselected white Caucasian NIDDM patients and 104 geographically matched and age-matched white Caucasian nondiabetic subjects. In addition, two silent polymorphisms were found with similar frequency in nondiabetic and diabetic subjects. Mutations in the gene for K-ATP2 are unlikely to be a major cause of MODY, NIDDM, or GDM.

Adenosine Triphosphate↗

PubMed1993

Cloning and functional expression in yeast of two human isoforms of the outer mitochondrial membrane channel, the voltage-dependent anion channel.

The voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane is a small abundant protein found in all eukaryotic kingdoms which forms a voltage-gated pore when incorporated into planar lipid bilayers. VDAC is also the site of binding of the metabolic enzymes hexokinase and glycerol kinase to the mitochondrion in what may be a significant metabolic regulatory interaction. Recently, there has been speculation that there may be multiple forms of VDAC in mammals which differ in their localization in the outer mitochondrial membrane and in their physiological function. In this report, we describe the identification and characterization of two human cDNAs encoding VDAC homologs (HVDAC1 and HVDAC2). To confirm VDAC function, each human protein has been expressed in yeast lacking the endogenous VDAC gene. Human proteins isolated from yeast mitochondria formed channels with the characteristics expected of VDAC when incorporated into planar lipid bilayers. In addition, expression of the human proteins in such strains can complement phenotypic defects associated with elimination of the endogenous yeast VDAC gene. Since VDAC is the site of binding of hexokinase to the outer mitochondrial membrane, the binding capacity of each VDAC isoform expressed in yeast mitochondria was assessed. When compared with the binding of hexokinase to mitochondria lacking VDAC, the results show that mitochondria expressing HVDAC1 are capable of specifically binding hexokinase, whereas mitochondria expressing HVDAC2 only bind hexokinase at background levels. The expression of each human cDNA has been assessed by Northern blot and polymerase chain reaction techniques. With one exception, each is expressed in all human cell lines and tissues examined.

Amino Acid Sequence↗

PubMed1992

Amplification and molecular cloning of the ornithine decarboxylase gene of Leishmania donovani.

A strain of Leishmania donovani has been described that is resistant to DL-alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase (OD-Case) activity, and contains 15-fold greater amounts of ODCase activity and protein than the wild type strain from which it was derived (Coons, T., Hanson, S., Bitonti, A.J., McCann, P.P., and Ullman, B. (1990) Mol. Biochem. Pharmacol. 39, 77-90). From this mutant strain, another ODCase overproducing L. donovani strain, DFMO16, was generated by virtue of its ability to proliferate under even higher concentrations of DFMO. To investigate the mechanism by which DFMO-resistant cells overexpress ODCase, the leishmanial ODCase gene was isolated by hybridization to a fragment of the L. donovani ODCase gene that was generated by the polymerase chain reaction. The nucleotide sequence of a 4.5-kilobase DNA fragment encompassed an open reading frame encoding 707 amino acids (Mr = 77,350). The leishmanial protein contained an extra approximately 200 amino acid NH2-terminal extension and lacked the COOH terminus of the mammalian ODCase. Northern blot analysis revealed two leishmanial OD-Case transcripts of 4.8 and 6.5 kilobases, both of which were amplified 10-20-fold in the DFMO16 cells. Genomic Southern blot analysis established that the augmented amount of ODCase activity and ODCase mRNA in the DFMO16 strain could be attributed to a approximately 10-20-fold amplification of the ODCase gene copy number. DFMO16 cells exhibited an unstable phenotype in that the amplification of the ODCase gene, the increased amount of ODCase transcript, the overproduction of ODCase activity, and the DFMO-resistance growth phenotype all reverted synchronously in the absence of selective pressure.

Amino Acid Sequence↗

PubMed1990

Cost-effectiveness of Veterans Administration hospital-based home care. A randomized clinical trial.

A randomized design was used to examine the cost-effectiveness of a Veterans Administration hospital-based home care program that case managed inpatient and outpatient care. Patients (N = 419) with two or more functional impairments or a terminal illness were randomized to hospital-based home care (n = 211) or customary care (n = 208). Functional status, satisfaction with care, and morale were measured at baseline and at 1 and 6 months after discharge from the hospital; health care utilization was tracked for 6 months. Findings included significantly higher (0.1 on a three-point scale) patient and caregiver satisfaction with care at 1 month and lower Veterans Administration and private sector hospital costs ($3000 vs $4245) for the experimental group. Net per person health care costs were also 13% lower in the experimental group. We conclude that this model of hospital-based home care is cost-effective and that its expansion to cover these two patient groups throughout the Veterans Administration system can improve patient care at no additional cost.

Aged↗

PubMed1983

Efficient bacterial expression of bovine and porcine growth hormones.

cDNAs prepared using poly(A)mRNA from pituitaries and containing the coding sequences for bovine and porcine growth hormones (bGH and pGH) were cloned in bacteria. The primary structures of the peptide hormones derived from the nucleotide sequences of the respective cDNAs show approximately 90% homology. The cloned cDNAs were modified using synthetic DNA to construct expression vectors for efficient bacterial production of the mature animal growth hormones.

Animals↗

PubMed1983

Primary structure of the human proenkephalin gene.

The nucleotide sequence of a 6.8-kb region of human DNA containing the proenkephalin gene and flanking regions is reported. The gene consists of four exons separated by three introns and spans approximately 5.3 kb of DNA. Location and identification of several repetitive DNA sequences within and flanking the gene are also described. The distribution of CpG dinucleotides as well as the extent of CpG methylation at several restriction sites within and surrounding the gene is also presented. The structural organization of the human proenkephalin gene exhibits striking similarities to the organization of the human pro-opiomelanocortin (POMC) gene. Nucleotide sequence homologies suggest that two opioid peptide precursors, proenkephalin and prodynorphin, may have arisen by duplication from a common ancestral gene.

5-Methylcytosine↗

PubMed1982

Primary structure of the human Met- and Leu-enkephalin precursor and its mRNA.

The nucleotide sequence of a complete cDNA copy of enkephalin precursor mRNA from human phaeochromocytoma is reported. The corresponding amino acid sequence shows that the precursor is 267 amino acids long and contains six interspersed Met-enkephalin sequences and one Leu-enkephalin sequence. Five of the seven enkephalins are flanked on both sides by pairs of basic amino acid residues. The precursors does not contain the sequences of the opioid peptides, dynorphin, alpha-neo-endorphin or beta-endorphin.

Amino Acid Sequence↗

PubMed1981

The sequence of human serum albumin cDNA and its expression in E. coli.

A recombinant plasmid has been constructed which contains the mature protein coding region of the human serum albumin (HSA) gene. Bacteria containing this plasmid synthesize HSA protein under control of the E. coli trp promoter-operator. The DNA sequence and predicted protein sequence of HSA were determined from the cDNA plasmid and are compared to existing data obtained from direct protein sequencing. The DNA sequence predicts a mature protein of 585 amino acids preceded by a 24 amino acid "prepro" peptide.

Amino Acid Sequence↗

PubMed1981

DNA sequence of two closely linked human leukocyte interferon genes.

A single recombinant lambda bacteriophage isolated from a human genome library contains two closely related human interferon genes of the leukocyte or alpha type. The two genes are separated by 12 kilobase pairs and are oriented in the same direction with respect to transcription. Comparisons of the DNA sequences of these two genes and interferon complementary DNA clones indicate that the two interferon genes lack intervening sequences.

Bacteriophage lambda↗

PubMed1981

Human fibroblast interferon gene lacks introns.

A recombinant lambda bacteriophage isolated from a human genome library contains the gene for fibroblast interferon (IFN-beta1). The DNA sequence of this gene is identical to the sequence of its mRNA and is devoid of introns.

Bacteriophage lambda↗

PubMed1978

The changing urban-suburban distribution of medical practice in large American metropolitan areas.

The twenty largest multi-county SMSAs in the U. S. were studied for trends in the suburbanization of medical practice from 1959 to 1974. Fifteen of them allowed a distinction between suburbs and central city on the county level according to criteria developed from a New York City pilot study. In all SMSAs, the density of hospital-based physicians was higher in central cities than in suburbs and still increasing more rapidly there, though hospital practice is also starting to grow in the suburbs at an appreciable rate. The same trends were found for physicians in non-patient care activities. Office based specialists in large Northeastern SMSAs increased much more rapidly in the urbanized suburbs than in the central cities. In the Southern and Western SMSAs, on the contrary, office-based specialists continued to increase rapidly in the central cities despite concentrations already far greater than in the Northeast. Suburban desities were growing more slowly in these areas. General practitioners declined uniformly everywhere, apparently simply by attrition. Implications of these trends for health care are discussed.

Family Practice↗