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Biomedical subjects

D Perlman

Publications and source records attributed to D Perlman.

At least 19 recordsLinked to original sources
PubMed1991

Structural and phylogenetic analysis of the chicken ventricular myosin heavy chain rod.

We have isolated and characterized five overlapping clones that encompass 3.2 kb and encode a part of the short subfragment 2, the hinge, and the light meromyosin regions of the myosin heavy chain rod as well as 143 bp of the 3' untranslated portion of the mRNA. Northern blot analysis showed expression of this mRNA mainly in ventricular muscle of the adult chicken heart, with trace levels detected in the atrium. Transient expression was seen in skeletal muscle during development and in regenerating skeletal muscle following freeze injury. To our knowledge, this is the first report of an avian ventricular myosin heavy chain sequence. Phylogenetic analysis indicated that this isoform is a distant homolog of other ventricular and skeletal muscle myosin heavy chains and represents a distinct member of the multigene family of sarcomeric myosin heavy chains. The ventricular myosin heavy chain of the chicken is either paralogous to its counterpart in other vertebrates or has diverged at a significantly higher rate.

Amino Acid Sequence↗
PubMed1991

Intrathecal baclofen for severe spasticity: five years experience.

Severe spasticity is a major problem in the rehabilitation of patients with dysfunction of the spinal cord or cerebral hemispheres. Oral baclofen is often effective. However, in patients with severe spasticity adequate control may not be obtained from oral therapy with the drug. Over the past 5 years we have developed a program for the use of intrathecal baclofen for severe spasticity, and in relation to this discuss patient assessment, practical aspects of drug administration, complications of therapy and patient benefits. Continuous intrathecal baclofen is a safe and effective adjunct to physical therapy in the management of patients with severe spasticity.

Adult↗
PubMed1979

Application of oxygen-enriched aeration in the production of bacitracin by Bacillus licheniformis.

The physiological effects of controlling the dissolved oxygen tension at 0.01, 0.02, and 0.05 atm by the use of oxygen-enriched aeration were investigated during growth and bacitracin production by Bacillus licheniformis ATCC 10716. Up to a 2.35-fold increase in the final antibiotic yield and a 4-fold increase in the rate of bacitracin synthesis were observed in response to O(2)-enriched aeration. The increase in antibiotic production was accompanied by increased respiratory activity and an increase in the specific productivity of the culture from 1.3 to 3.6 g of antibiotic per g of cell mass produced. Oxygen enrichment of the aeration decreased medium carbohydrate uptake and the maximum specific growth rate of B. licheniformis from 0.6 h(-1) to as low as 0.15 h(-1), depending upon the level of enrichment and the conditions of oxygen transfer rate (impeller speed). The response of this culture to O(2) enrichment suggests that this method of controlling the dissolved oxygen tension for antibiotic-producing cultures may simulate conditions that would occur if the carbon source were fed slowly, as is often employed to optimize antibiotic production. Analysis of the biologically active bacitracins produced by B. licheniformis ATCC 10716 suggested that the ratio of biologically active peptides was not changed by O(2) enrichment, nor were any new biologically active compounds formed.

Bacillus↗
PubMed1978

Cross-cultural analysis of students' sexual standards.

Our purpose was to investigate, cross-culturally, university students' premarital sexual standards. A number of predictions were derived from the work of Cristensen, Reiss, and Burr. Data were collected via self-administered questionnaires from over 1100 English-speaking respondents in five "cultures" (four countries). These cultural contexts had a strong effect on the attitudes and behavior of individual respondents. As predicted, the difference in the standards held by males and females was small in highly permissive societies. Negative consequences of premarital intercourse (i.e., guilt) were reported by the highest proportion of sexually experienced respondents in the most restrictive society. An unsuccessful effort was made to predict how the correlation between permissiveness and such variables as religiosity would change in different cultures. Across all five cultures, greater courtship participation, less religiosity, greater physical attractiveness, and spending less time with one's family were associated with greater permissiveness. Finally, students from high-status backgrounds were generally more permissive.

Adolescent↗
PubMed1978

Characteristics of bacteriophages for Micromonospora purpurea.

Chemical and physical stabilities of bacteriophages øUW 21 and øUW 51 infecting Micromonospora purpurea ATCC 15835 were examined. Both phages were stable over the pH range of 5 to 8 and to heating at temperatures up to 50 degrees C and especially stable in buffer containing magnesium ion. Exposure to 1 M Ca(NO3)2 inactivated both phages, and phage øUW 51 was also susceptible to 1 M CaCl2, 0.1 M tris(hydroxymethyl)aminomethane, and 0.3% H2O2. Phage plating efficiency was highest on the cultures at logarithmic phase and sometimes much influenced by host growth. Phage øUW 51 has a latent period of 2 h at 34 degrees C and a burst size between 35 and 40. The latent period for phage øUW 21 is about 12 h, and the burst size is smaller than 30.

Bacteriophages↗
PubMed1978

Frequency of replication from alternative origins in the composite R plasmid NR1.

The relative frequency of initiation of DNA replication within the RTF-Tc and r-determinant components of the composite drug resistance plasmid NR1 in Proteus mirabilis was evaluated. Using fractionated radioactively labeled plasmid DNA, analytical procedures that distinguished between the two components of the composite plasmid were carried out. A mixture of uniformly 14C-labeled and 3H-pulse-labeled plasmid DNA (pulse-labeled origin[s] of replication) was used in each of three experiments. First, shear products of the DNA were analyzed using CsCl density gradient centrifugation. Second, fragmented DNA was hybridized to nonradioactive RTF-Tc and r-determinant DNAs immobilized on nitrocellulose filters. Third, the radioactive plasmid DNAs immobilized on nitrocellulose filters. Third, the radioactive plasmid DNA was digested with restriction enzyme (EcoRI), producing a set of RTF-Tc and r-determinant fragments with differing 3H/14C isotpe ratios. The three experiments suggested that under the conditions used to accumulate replicating plasmid DNA molecules (DNA substrate limitation), the r-determinant origin of replication was preferentially utilized in the composite plasmid.

DNA Replication↗
PubMed1977

Fermentation of glucose by Acetobacter melanogenus.

Growing cultures of Acetobacter melanogenus ATCC 9937 concerted D-glucose to 2,5-diketo-D-gluconic acid with D-gluconic acid and 5-keto-D-gluconic acid as intermediates. The 2,5-diketo-D-gluconic acid was isolated from the fermented medium by treatment with an anion exchange resin.

Acetobacter↗
PubMed1977

Selective amplification of genes on the R plasmid, NR1, in Proteus mirabilis: an example of the induction of selective gene amplification.

The drug-resistance plasmid, NR1, is a 37-micron circular DNA molecule that contains two components: the resistance transfer factor (29 micron) carrying the transfer genes and the genes for tetracycline resistance, and the r-determinant (8 micron) carrying the genes for resistance to several other antibiotics including chloramphenicol (Cm). In Proteus mirabilis, these two components are capable of independent replication, or they may replicate as a composite molecule. When cells of P. mirabilis containing NR1 are cultured in medium containing Cm at 250 microgram/ml a growth lag of 20-35 hr ensues. During this lag, Cm induces the selective amplification of the r-determinant, including the gene for resistance to Cm. The amplification results from the excision of the r-determinant from the R plasmid, the independent replication of the r-determinant to give polymeric as well as monomeric r-determinants, and the eventual reintegration of multiple tandem copies of the r-determinant with the resistance transfer factor to form a new R plasmid with multiple copies of the r-determinant. This mechanism represents a new level of control of gene expression in bacterial systems--namely, the induction of selective gene amplification.

Cell Division↗