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Biomedical subjects

M Cohen

Publications and source records attributed to M Cohen.

At least 973 records · Page 54Linked to original sources
PubMed1977

Sequence arrangement of tRNA genes on a fragment of Drosophila melanogaster DNA cloned in E. coli.

A plasmid with the vector Col E1 attached to an insert of Drosophila melanogaster DNA carrying four tRNA genes has been cloned in E. coli. Some features of the sequence arrangement and the positions of the tRNA genes have been determined by electron microscopic methods and by restriction endonuclease mapping. tRNA genes were mapped at 1.4, 4.7, 5.9 and 8.6 kb from one of the Drosophila/Col E1 junctions in the Drosophila insert of total length 9.34 kb. There are several secondary structure features consisting of inverted repeat sequences of length about 70-100 nucleotide pairs, some with and some without intervening loops, irregularly distributed on the insert. Cross-hybridization of tRNAs isolated by hybridization to separated restriction fragments indicate that the tRNA genes at 4.7, 5.9 and 8.6 kb are identical and differ from the one at 1.4 kb. Thus the positions of the genes, of the secondary structure features and of the restriction endonuclease sites all indicate that the spacers between the genes are not identical tandem repeats. In situ hybridization with cRNA transcribed from the plasmid showed localization at region 42A of chromosome 2R.

Animals↗
PubMed1977

Maturation and anaplasia in neuronal tumors of the peripheral nervous system; with observations on the glial-like tissues in the ganglioneuroblastoma.

Six cases of peripheral ganglioneuroblastoma are described and analyzed; in general these contained neuroblasts, mature ganglion cells and cells of intermediate degrees of maturity. Portions of the tumor resembled the glial tissues of the central nervous system, but this is spurious, no glial cells or fibers being present. Such tissues contained cells of intermediate maturity, immature axons which characteristically stain poorly with silver stains for axons, and a paucity of connective tissue fibers. These tumors exhibit a tendency for continued maturation with decreased malignancy, and for anaplastic change with increased malignancy. These opposing tendencies make it difficult to predict the outcome with complete certainty, except possibly in those cases in which maturation is complete. Schwann cells are present in those tissues which have matured to form neurons with axonal processes. The Schwann cells are probably reactive, not neoplastic. The presence of Schwann cells in such mature tissues is most readily explained on the assumption that Schwann cells are mesenchymal in character, and have been formed by differentiation of multipotential primitive reticular cells in response to the formation of axons by the maturing neurons.

Adult↗
PubMed1977

Immediate and late onset asthma from occupational exposure to soybean dust.

Most patients sensitive to soybean experience gastrointentinal symptoms, urticaria, angioedema, and asthma after ingestion. However, we report here a previously non-allergic patient who developed immediate and late onset asthma after breathing soybean flour used in the manufacture of food supplements. She exhibited positive immediate and late skin test sensitivity as well as a positive bronchial challenge to a soybean flour extract. In contrast to another patient with an anaphylactic response after soybean ingestion, the radioallergosorbent test (RAST) to soybean antigen was negative in our patient.

Adult↗
PubMed1977

Adequacy of sexual performance in men maintained on methadone.

Impairment of sexual performance may occur in men on methadone maintenance. A random sample of 50 of 355 men enrolled in a methadone program was interviewed with respect ot sexual activity. Seventeen (33%) reported sexual dysfunction, occurring in 50% within 1 month after initiating methadone therapy. A comparison between these individuals and those without a reported change in sexual activity revealed no differences with respect to demographic parameters, methadone dose, or presence of polydrug abuse. Inadequate sexual function on heroin, however, was reported in 12 (71%) of those experiencing similar difficulties on methadone. This finding was present in only one person (3%) of those individuals whose sexual function on methadone maintenance was considered adequate. This study suggests that those persons with altered sexual function while on street heroin represent a high risk group for the development of inadequate sexual function upon initiation of methadone maintenance.

Adult↗
PubMed1977

The use of an alcoholism screening test to identify the potential for alcoholism in persons on methadone maintenance.

Alcoholism has become a problem of increasing prominence in persons enrolled in methadone maintenance programs. Since early identification of the potential problem drinker may result in successful intervention, a method to screen individuals applying for admission to methadone maintenance who have a proclivity toward alcoholism would be of great value. A modified self-administered alcoholism screening test (SAAST), previously confirmed to identify "hidden alcoholics" in a general nonnarcotic-using population, was utilized as a screening device in three groups of narcotic-dependent persons on methadone maintenance: 30 individuals who had a known problem with alcoholism, 30 individuals without any history or signs of alcoholism over an extended time period, and 80 persons entering methadone maintenance who initially denied any problems with excessive drinking. The ability of the modified SAAST to separate the alcoholic from the nonalcoholic narcotic addict was confirmed (p less than 0.001). This test was also found to have considerable predictive value in determining those individuals initially denying a history of excessive alcohol intake who become problem drinkers.

Alcoholism↗
PubMed1977

The usefulness and reliability of a drug severity scale.

This paper reports on the interrater reliability of a previously developed method for measuring severity of multidrug use. This method is based on interviewer's ratings of the number of different drugs used, the frequency of use, and the length of use of each drug. The results show that relatively unsophisticated raters in comparison with trained and experienced raters are able to utilize the drug severity form with a minimum of error.

Humans↗
PubMed1977

Primary acquired hypogammaglobulinemia and regional enteritis.

We had a patient with primary acquired hypogammaglobulinemia (PAH), nodular lymphoid hyperplasia, giardiasis, and the subsequent development of regional enteritis (RE). The case is of interest because the development of regional enteritis in a patient with PAH has not been previously reported, to our knowledge. The interaction of hypogammaglobulinemia and RE is discussed from an immunologic point of view. The report adds RE to the many known bowel diseases associated with PAH.

Adult↗
PubMed1976

Ectopic pairing and evolution of 5S ribosomal RNA genes in the chromosomes of Drosophila funebris.

5S ribosomal RNA from Drosophila melanogaster labeled with 125I was used to locate the 5S rRNA genes in chromosomes of D. funebris by means of in situ hybridization. Silver grains were observed at three distinct sites, one of which was a recognized reverse repeat. Only one half of the reverse repeat, however, hybridizes with 5S rRNA and the significance of this phenomenon is discussed. A case of ectopic pairing between two different 5S sites in the genome is reported, and the significance of ectopic pairing is considered.

Animals↗
PubMed1976

Evolution of 5S ribosomal RNA genes in the chromosomes of the virilis group of Drosophila.

Drosophila melanogaster 5S ribosomal RNA labeled with 125I was used as an in situ hybridization probe to localize complementary sequences in chromosomes of species in the Drosophila virilis group. Whereas virilis, the ancestral species, has two different 5S gene loci, the derived species show only one of these loci; in the two lines that have evolved from virilis it is the opposite locus that is conserved. The possible events leading to such an arrangement are discussed.

Animals↗
PubMed1976

The first urinary tract infection in male children.

In a prospective study of urinary tract infection in 57 boys, diagnosis in 50 patients was based on the presence of more than 10(5) organisms per milliliter of urine. Gram-positive cocci were more prevalent, and Escherichia coli was less prevalent than previously reported in girls. Fever and urinary tract abnormalities were frequent in boys younger than 10 years of age; less common in boys 10 to 14 years old. Excretory urography and voiding cystourethrography were performed in 30 boys. In 15, one or both showed abnormalities, usually vesicoureteral reflux. Most of the abnormalities, and all of those that necessitated surgical correction, were in boys under 10 years old. In the remaining seven patients, less than 10(3) organisms per milliliter grew on urine culture. All of the seven were younger than 10 years of age, and all had serious renal abnormalities, three requiring surgical correction.

Adolescent↗