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Biomedical subjects

H Perry

Publications and source records attributed to H Perry.

At least 37 records · Page 2Linked to original sources
PubMed1988

Oligopeptides inhibit the ribonucleotide reductase of herpes simplex virus by causing subunit separation.

It has recently been reported that a nonapeptide (H-Tyr-Ala-Gly-Ala-Val-Val-Asn-Asp-Leu-OH) identical in sequence to the last nine amino acid residues of RR2, the small subunit of herpes simplex virus (HSV) ribonucleotide reductase (E.C. 1.17.4.1; RR), can inhibit HSV RR activity in vitro. It has been postulated that this peptide acts by interfering with the interaction of the large subunit, RR1, and RR2, but direct demonstration of its mechanism of action has not been reported. We present data which show that the inhibition of HSV RR by this oligopeptide is due to induced subunit dissociation.

Macromolecular Substances↗
PubMed1986

The nicotinic-induced release of endogenous dopamine from rat striatal slices from animals chronically exposed to dimethylphenylpiperazinium (DMPP).

The effect of the nicotinic agonist, dimethylphenylpiperazinium (DMPP), to release endogenous dopamine (DA) from striatal slices obtained from animals chronically treated with the nicotinic agonist for 7 or 14 days was determined. Endogenous DA was measured by high pressure liquid chromatography coupled to electrochemical detection. There was no difference in the DMPP concentration-effect curve for DA release from slices obtained from untreated rats or rats treated with saline. Treatment with DMPP for 7 days did not change the DMPP concentration-effect curve when compared to saline treatment. In contrast, treatment of rats with DMPP for 14 days resulted in a significant attenuation of the DMPP-induced release of DA. These studies support the hypothesis that chronic treatment with nicotinic agonists results in a functional uncoupling of cholinergic nicotinic receptors facilitating DA release in the striatum.

Animals↗
PubMed1985

Cefamandole levels in serum and necrotic bone.

Seven patients with chronic osteomyelitis were treated by surgical debridement. Cefamandole was administered intravenously before surgery. During the debridement, cefamandole concentrations were measured in serum and necrotic bone. Although adequate levels of antibiotic were achieved in the serum, minimal or no concentration of antibiotic was found in the necrotic bone. There was only minimal penetration of cefamandole into necrotic bone.

Bone and Bones↗
PubMed1984

Echinocandin inhibition of 1,3-beta-D-glucan synthase from Candida albicans.

The cyclic peptide antibiotic echinocandin was found to inhibit 1,3-beta-D-glucan synthase activity present in a mixed membrane fraction from Candida albicans. Addition of antibiotic reduced the Vmax of the enzyme, but the Km was unaffected. GTP stimulated enzyme activity approximately 4-fold, but did not affect the percentage inhibition of the enzyme by echinocandin. Treatment of the reaction products with alpha-amylase and beta-glucanase confirmed that the polymer synthesised was 1,3-beta-D-glucan, not glycogen.

Anti-Bacterial Agents↗
PubMed1984

Enrollment and demographic characteristics of physician's assistant students.

The authors in this paper describe enrollment trends and provide demographic information for a representative sample of physician's assistant (PA) students enrolled during 1978-1982 in 46 PA programs accredited by the American Medical Association. In February 1983, there were 2,871 such students enrolled in 54 primary care and three surgeon's assistant programs. The typical PA program, which is two years in length, provides six to nine months of preclinical course work and nine to 15 months of clinical experience. Most programs are based in either medical schools or four-year colleges and offer baccalaureate degrees. From the demographic information obtained by the authors from this sample, the typical PA student is 28 years old and has three to four years of college and one to two years of prior health care experience. There has been a steady increase in the enrollment of women and individuals with four or more years of college. More than half of the PA students enrolled in 1983 were women. Former military medical corpsmen, who once predominated the PA profession, now represent only a small proportion of the PA student population. Most PA students continue to want to practice with family practitioners in small communities.

Adult↗
PubMed1983

A comparison of the antiviral agents 2'-nor-2'-deoxyguanosine and acyclovir: uptake and phosphorylation in tissue culture and kinetics of in vitro inhibition of viral and cellular DNA polymerases by their respective triphosphates.

A comparative study was conducted between the antiherpetic agents 2'-nor-2'-deoxyguanosine (2'NDG) and acyclovir (ACV) with respect to 1) the relative rates of uptake and phosphorylation to the "active" triphosphate species in tissue culture and 2) the in vitro inhibition of viral and cellular DNA polymerases by their respective triphosphates. The results indicated that a) six hours after HSV1 infection of primary rabbit kidney cells there was seven times more 2'NDG-triphosphate in the cells than ACV triphosphate; b) the relative rate of triphosphate formation in HSV1-infected versus uninfected cells was 4.5 times higher for 2'NDG than for ACV and c) the triphosphate of 2'NDG (2'NDG-TP) was a more selective inhibitor of the viral compared to the cellular DNA alpha-polymerase than the triphosphate of ACV (ACV-TP). The Km/Ki ratios for 2'NDG-TP and ACV-TP (in the competitive inhibition of dGTP) were 3.10 and 1.37, respectively, for the highly purified HSV1 polymerase; and 0.05 and 1.11, respectively, for the partially-purified HeLa alpha-polymerase. Neither triphosphate inhibited the HeLa DNA beta-polymerase to any significant extent. These results are in line with the findings [Ashton et al. (1982), Biochem. Biophys. Res. Commun. 108, 1716-1721] that 2'NDG has superior in vivo antiherpetic activity compared to ACV without apparent toxicity.

Acyclovir↗
PubMed1983

Release of dopamine and 5-hydroxytryptamine from rat striatal slices following activation of nicotinic cholinergic receptors.

1. The administration of the nicotinic cholinergic agonists dimethylphenylpiperazinium iodide (DMPP) or nicotine caused a concentration dependent release of [3H] dopamine, [3H]5-hydroxytryptamine as well as endogenous dopamine and 5-hydroxytryptamine from superfused slices of rat striatum. 2. Release of both labelled and non-labelled transmitter was antagonized by the nicotinic antagonist, hexamethonium but not the muscarinic antagonist, atropine. 3. The present study provides additional evidence that nicotinic-cholinergic receptors are present in the mammalian central nervous system. 4. Activation of these nicotinic-cholinergic receptors in the striatum results in the release of both dopamine and 5-hydroxytryptamine.

Animals↗
PubMed1978

Mucinous cystadenocarcinoma of the ovary.

Reports of 78 cases of mucinous cystadenocarcinoma of the ovary were collected from the Emil Novak Ovarian Tumor Registry and the files of the Gynecologic Pathology Laboratory of the Johns Hopkins Hospital between the years 1942 and 1966. Two-year and 5-year followups were available for 91 and 83% of the cases, respectively. The prognosis was related to the most aggressive area of the tumor as the histologic grade was based on the maximum number of mitoses per high-powered field. In view of the clinical and histopathologic differences between these lesions and the serous and endometrioid varieties, it is suggested that each tumor be considered on its own merits in order to offer an accurate prognosis.

Adult↗
PubMed1977

Fatal radiation pneumonia following subclinical busulfin injury.

A patient with polycythemia vera received a moderate dose (480 mg) of busulfan intermittently over a 6 year period and later developed Hodgkin's disease. Following split-course upper mantle, chest irradiation, he developed rapidly progressive, fatal pneumonia and bone marrow hypoplasia. It is postulated that the hyperacute organ failures (lung and bone marrow) resulted from augmentation of subclinical busulfan-induced damage of these organs by additive radiation effect. It is recommended that in patients who have had antineoplastic chemotherapy, major radiotherapy to the cervicothoracic region be accompanied by careful monitoring of respiratory and hematopoietic function, both before and during radiotherapy.

Aged↗
PubMed1975

A data acquisition system for three-dimensional treatment planning.

The authors describe a coordinate measuring device developed to simplify manual acquisition of the digital information required for computerized three-dimensional treatment planning. This system has been used for two years and shown to be both fast and accurate. The time needed to digitize contour data is reduced to approximately one-tenth of that required for manual methods in most cases.

Computers↗