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Biomedical subjects

J B Murphy

Publications and source records attributed to J B Murphy.

At least 55 records · Page 3Linked to original sources
PubMed1987

Primary Kaposi's sarcoma of an intraparotid lymph node with AIDS.

A case of Kaposi's sarcoma of an intraparotid lymph node in a patient with previously undiagnosed AIDS is presented. In patients at risk for AIDS who present with undiagnosed head and neck tumors, the diagnosis of epidemic Kaposi's sarcoma should be considered. Although transmission of AIDS to health care workers is exceedingly rare, proper precautions should be exercised when working with these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Abnormalities of ejaculation.

The normal physiologic processes of emission and ejaculation require coordination of neurophysiologic, anatomic, and, in certain cases, psychological phenomena. Disruption of any component, from the embryologic development of the müllerian duct through the medications used for nonrelated systemic disease, can alter the efficient function of ejaculation. Evaluation of the urologic patient who has any of a number of abnormal ejaculatory states requires an understanding of the many possible mechanisms of failure. The majority of these men need evaluation because of a possible male-factor infertile marriage. The potential for improvement is significant, given the development of improved techniques to stimulate ejaculation and the promise shown by extracorporeal fertilization techniques such as in vitro fertilization and gamete intrafallopian tube transfer. These patients deserve complete assessment and optimization of any factors that will enable them to achieve their goal of procreation.

Adolescent↗
PubMed1986

Escherichia coli exonuclease VII. Cloning and sequencing of the gene encoding the large subunit (xseA).

We have determined the sequence of the gene encoding the large subunit of Escherichia coli exonuclease VII (xseA) and the amino acid sequence of the protein it encodes. The coding region of the xseA gene is 1368 base pairs. The protein encoded by the gene contains 456 amino acids and has a calculated molecular weight of 51,823. The promoter for xseA is close to that for guaB, and these two genes are transcribed in opposite directions: xseA clockwise and guaB counterclockwise on the standard E. coli genetic map. The cloned xseA gene can complement an xseA deletion mutant strain. In an xseA+ genetic background production of large quantities of the xseA gene product appeared to decrease the amount of exonuclease VII activity in cell extracts. In fact, no exonuclease VII activity at all could be detected following induction of strains in which the xseA gene was under lambda pL regulation. These observations suggest that the proper ratio of the large and small exonuclease VII subunits must be maintained in order to produce active enzyme.

Amino Acid Sequence↗
PubMed1985

A monoclonal antibody that recognizes the functional domain of Escherichia coli single-stranded DNA binding protein that includes the ssb-113 mutation.

We have isolated a monoclonal antibody against Escherichia coli single-stranded DNA binding protein (SSB) that recognizes the functional domain specified by the ssb-113 temperature-sensitive mutation, a domain which is distinct from the DNA-binding site. Although the ssb-113 and ssb-1 mutations result in many similar phenotypic defects, they differ significantly in others, indicating that they affect different functional domains of the protein. Whereas the SSB-1 mutant protein is clearly defective in tetramer formation and is also unable to bind single-stranded DNA at nonpermissive temperatures, no similar in vitro defects have yet been found in the SSB-113 mutant protein. In fact, the only reported in vitro effect of the ssb-113 mutation on the protein is a slight increase in its helix destabilizing ability. Competition radioimmunoassays using a monoclonal antibody demonstrated that SSB-113 mutant protein, containing a single amino acid substitution at position 176 (the penultimate residue), did not compete with SSB while SSB-1 protein (with a single change at position 55) did compete with SSB. This analysis was refined by studies with a proteolysis fragment and with peptides derived from both SSB and SSB-113. The results indicate that the antibody recognizes a determinant near the COOH-terminal end of the protein and that the SSB-113 mutation lies within or very close to this determinant.

Antibodies, Monoclonal↗
PubMed1985

Diagnosis of acute maxillofacial infections: the role of computerized tomography.

Most acute maxillofacial infections are diagnosed by conventional dental and maxillofacial radiographic techniques. Computed tomography has greatly improved our ability to evaluate infections of the maxillofacial region that originate or extend into the contiguous soft tissues and paranasal sinuses. Four cases in which computed tomography facilitated diagnosis and treatment of advanced infections of the maxillofacial region are presented. In one case an underlying neoplasm was identified.

Adult↗
PubMed1985

A 6-year experience with immediate reconstruction after mastectomy for cancer.

A 6-year retrospective review is presented of 185 patients who underwent immediate reconstruction of the breast at the same operation as mastectomy for carcinoma. The patients were treated at two institutions under similar protocols of patient selection, surgical technique, and postoperative care. A detailed evaluation is presented from both the oncologic and surgical points of view. The data support the conclusion that immediate reconstruction of the breast does not alter survival or cancer recurrence rates and does not interfere with the treatment of primary or secondary disease. A low incidence of significant surgical complications is also detailed. Combined with previous reports answering psychological concerns about this mode and timing of reconstruction, this review offers significant reassurance about the overall safety of immediate reconstruction. The authors therefore recommend immediate reconstruction of the breast as a safe treatment option for the woman facing mastectomy.

Adult↗
PubMed1985

Bicarbonate-Reversible and Irreversible Inhibition of Photosystem II by Monovalent Anions.

We tested a number of inhibitory monovalent anions for their primary site of action on photosystem II(PSII) in chloroplasts. We find that the inhibitory effects of F(-), HCO(2) (-), NO(2) (-), NO(3) (-), and CH(3)CO(2) (-) are all reversed by addition of a high concentration of HCO(3) (-). This class of anions competitively inhibits H(14)CO(3) (-) binding to PSII. All of those anions tested reduced H(14)CO(3) (-) binding more in the light than in the dark. We conclude that the primary inhibitory site of action of a number of monovalent anions is at the HCO(3) (-) binding site(s) on the PSII complex. The carbonic anhydrase inhibitor gold cyanide, and also azide, inhibit PSII but at a site other than the HCO(3) (-) binding site. We suggest that the unique ability of HCO(3) (-) to reverse the effects of inhibitory anions reflects its singular ability to act as a proton donor/acceptor at the anion binding site. A similar role has been proposed for non-substrate-bound HCO(3) (-) on carbonic anhydrase by Yeagle et al. (1975 Proc Natl Acad Sci USA 72: 454-458).

Journal Article↗
PubMed1984

Characterization of the structural and functional defect in the Escherichia coli single-stranded DNA binding protein encoded by the ssb-1 mutant gene. Expression of the ssb-1 gene under lambda pL regulation.

The ssb-1 gene encoding a mutant single-stranded DNA binding protein (SSB-1) has been cloned into a vector placing its expression under lambda pL regulation. This construction results in more than 100-fold increased expression of the mutant protein following temperature induction. Tryptic peptide analysis of the mutant protein by high-pressure liquid chromatography and solid-phase protein sequencing has shown that the ssb-1 mutation results in these substitution of tyrosine for histidine at residue 55 of SSB. This change could only occur in one step by a C----T transition in the DNA sequence which has been confirmed. Physicochemical studies of the homogeneous mutant protein have shown that in contrast to that of the wild-type SSB, the tetrameric structure of SSB-1 is unstable and gradually dissociates to monomer as the protein concentration is decreased from about 10 microM to less than 0.5 microM. The SSB-1 tetramer appears to be stable to elevated temperature (45 degrees C) but the monomer is not. We estimate the normal cellular concentration of SSB-1 (single chromosomal gene) to be 0.5-1 microM. Thus, there is a plausible physical explanation for our previous finding that increased expression of ssb-1 reverses the effects of a single gene (chromosomal) copy amount of SSB-1 (Chase, J.W., Murphy, J.B., Whittier, R.F., Lorensen, E., and Sninsky, J.J. (1983) J. Mol. Biol. 164, 193-211). However, even though the in vivo effects of ssb-1 and most of the in vitro defects of SSB-1 protein are reversed simply by increasing SSB-1 protein concentration, the mutant protein is not as effective a helix-destabilizing protein as wild-type SSB as measured by its ability to lower the thermal melting transition of poly[d-(A-T)].

Chromatography, Affinity↗
PubMed1984

Characterization of the Escherichia coli SSB-113 mutant single-stranded DNA-binding protein. Cloning of the gene, DNA and protein sequence analysis, high pressure liquid chromatography peptide mapping, and DNA-binding studies.

The ssb-113 (formerly lexC113) gene encoding a mutant single-stranded DNA binding protein (SSB) has been cloned into plasmid pSC101 resulting in 5- to 10-fold more mutant protein than strains carrying only one (chromosomal) copy of the gene. Analysis of tryptic and chymotryptic peptides of the mutant protein by high pressure liquid chromatography and solid phase protein sequencing has shown that the ssb-113 mutation results in the substitution of serine for proline at residue 176 of SSB. This change could only occur in one step by a C leads to T transition in the DNA sequence. Physicochemical studies of the homogeneous mutant protein have shown that it binds as well as wild type SSB to single-stranded DNA and that it is a slightly better helix-destabilizing protein than wild type SSB as measured by its ability to lower the thermal melting transition of poly[d(A-T)]. In vivo studies of ssb-113 strains carrying the cloned ssb-113 gene in pSC101 have shown that overproduction of the mutant protein does not complement the temperature-sensitive conditional lethality caused by the ssb-113 mutation when present in single gene copy in contrast to effects recently observed in ssb-1 strains overproducing the ssb-1 encoded protein (Chase, J. W., Murphy, J. B., Whittier, R. F., Lorensen, E., and Sninsky, J. J. (1983) J. Mol. Biol. 164, 193-211). Also noted in this report are two corrections to the DNA sequence of wild type SSB, one of which places glycine (codon GGC) at residue 133 rather than serine as previously reported (Sancar, A., Williams, K. R., Chase, J. W., and Rupp, W. D. (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 4274-4278). The second correction to the DNA sequence is in the serine 39 codon, previously reported to be TCA and now correctly shown to be TCC.

Amino Acid Sequence↗
PubMed1983

Amplification of ssb-1 mutant single-stranded DNA-binding protein in Escherichia coli.

The ssb-1 gene encoding a mutant Escherichia coli single-stranded DNA-binding protein has been cloned into plasmid pACYC184. The amount of overproduction of the cloned ssb-1 gene is dependent upon its orientation in the plasmid. In the less efficient orientation, 25-fold more mutant protein is produced than in strains carrying only one (chromosomal) copy of the gene; the other orientation results in more than 60-fold overproduction of this protein. Analysis of the effects of overproduction of the ssb-1 encoded protein has shown that most of the deficiencies associated with the ssb-1 mutation when present in single gene copy, including temperature-sensitive conditional lethality and deficiencies in amplified synthesis of RecA protein and ultraviolet light-promoted induction of prophage lambda +, are reversed by increased production of ssb-1 mutant protein. These results provide evidence in vivo that SSB protein plays an active role in recA-dependent processes. Homogenotization of a nearby genetic locus (uvrA) was identified in the cloning of the ssb-1 mutant gene. This observation has implications in the analysis of uvrA- mutant strains and will provide a means of transferring ssb- mutations from plasmids to the chromosome. On a broader scale, the observation may provide the basis of a general strategy to transfer mutations between plasmids and chromosomes.

Bacterial Proteins↗
PubMed1983

Retrograde method for percutaneous access to kidney.

A technique is described for gaining percutaneous access to the kidney by puncturing from inside out using a retrograde catheter and a sharpened stainless steel stylet. The method allows precise placement of a percutaneous tract in the nondilated upper urinary tract.

Animals↗
PubMed1982

Transitional cell carcinoma of the bladder metastatic to the breast.

This report is the first described case of transitional cell carcinoma of the bladder metastatic to the female breast. The patient is a 42-year-old woman who underwent radical cystectomy three months prior to presentation with two asymptomatic right breast masses as the first evidence of widely metastatic bladder carcinoma. The mode of presentation is similar to that seen with other tumors metastatic to the breast and requires the clinician and pathologist to be able to distinguish this diagnosis from primary breast carcinoma.

Adult↗
PubMed1982

Temperature effects on seed imbibition and leakage mediated by viscosity and membranes.

The possible involvement of membranes and water viscosity in the temperature effects on imbibition and solute leakage of radish (Raphanus sativa var. Early Scarlet Globe) seeds and excised sugar pine (Pinus lambertiana Dougl.) embryos was evaluated. In these two seed materials, the temperature effect on initial rates of imbibition and solute leakage could be accounted for primarily by changes in water viscosity, the relationship being approximately linear. It appears that membranes are involved both in water uptake and solute leakage. Heat-killed radish seeds and sugar pine embryos exhibited significantly higher rates of imbibition and solute leakage than did viable ones. In addition, sugar pine embryos exhibited an abrupt change in rates of imbibition and solute leakage between 15 and 20 degrees C, resulting in abnormally high water uptake and solute leakage above this temperature.

Journal Article↗
PubMed1982

Temperature effects on oxidative metabolism of dormant sugar pine seeds.

When dormant sugar pine (Pinus lambertiana L.) seeds were imbibed at 5 degrees C, they showed a rapid increase in O(2) uptake, ATP level, and moisture content during the first 4 days. This was followed by a plateau phase until 60 days, after which a second significant increase in all three features occurred as dormancy was broken. During the plateau phase, conventional CN-sensitive respiration accounted for 74 to 79% of the total O(2) uptake. When dormant sugar pine seeds were imbibed at and maintained at 25 degrees C, a different pattern occurred. Water uptake was much more rapid during the first 4 days and no second increase occurred after 60 days because the seeds did not break dormancy. There was an initial burst of O(2) uptake and ATP formation, but these both declined abruptly after 24 to 48 hours. Levels about half those of seeds at 5 degrees C were maintained through the rest of a 90-day period. CN-sensitive respiration declined during imbibition at 25 degrees C, and accounted for only 55 to 61% of the total O(2) uptake. The inability of dormant sugar pine seeds to germinate at temperatures above about 17 degrees C may therefore result from initial temperature effects on membrane properties, leading to reduced O(2) uptake, reduced cytochrome oxidase electron transport activity, and lowered ATP levels.

Journal Article↗