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Biomedical subjects

P Gardner

Publications and source records attributed to P Gardner.

At least 127 records · Page 7Linked to original sources
PubMed1984

New affinity adsorbents containing deoxycytidine, deoxyadenosine, or deoxyguanosine and their interactions with deoxynucleoside-metabolizing enzymes.

3'-(4-Aminophenyl phosphate) derivatives of deoxycytidine (dCyd), deoxyadenosine (dAdo), and deoxyguanosine ( dGuo ) were synthesized. The inhibitory effects of these compounds on mammalian and bacterial deoxynucleoside kinases and several other deoxynucleoside-metabolizing enzymes were examined. The same derivatives were coupled to carboxyl-terminal Sepharose CL-6B (3-8 mumol of ligand/mL of gel), and each of the resulting affinity adsorbents was tested with various partially purified enzymes. Reasonable correlation between the inhibitory effect of a soluble deoxynucleoside 3'-phosphate diester and affinity of the corresponding Sepharose adsorbent for the enzyme was observed. Among the three dCyd kinases examined, only the bovine mitochondrial enzyme was adsorbed onto the dCyd-Sepharose column and eluted biospecifically by 1 mM dCyd (1400-fold purification). Its Ki toward the dCyd derivative was relatively low (1.1 mM), whereas no measurable inhibition was seen with mammalian cytosol or bacterial enzymes that did not stick to the column. The Ki of the dAdo derivative toward three dAdo kinases was more than 5 mM in each case, and none of these were retained by dAdo-Sepharose. Among the other dAdo-metabolizing enzymes examined, nucleoside phosphotransferase from barley (Ki = 1.2 mM) was adsorbed to dAdo-Sepharose at pH 5.0 and was biospecifically eluted with dAdo or AMP after suppressing ionic binding by adjusting the pH to 6.0 (480-fold purification to homogeneity). Mammalian mitochondrial dGuo kinase (beef liver) showed the lowest Ki (0.16 mM) among the enzymes tested and was biospecifically purified with dGuo -Sepharose (2800-fold purification).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Radiotherapy quality assurance in clinical trials.

The goal of radiation therapy is to yield the greatest possible uncomplicated local and regional tumor control. An acceptable quality of life with few severe complications, anatomical defects or psychological disturbances should be an integral objective of excellent radiation therapy. Inasmuch as higher doses of irradiation and adequacy of treatment portals (volume irradiated) appear to correlate with greater probability of tumor control and major complications, there is a critical need to optimize treatment planning and quality assurance in radiation therapy. Along with this, techniques must be developed for reliable patient reposition and immobilization so that the optimized treatment plan can be translated into precise delivery of the irradiation. It is obvious that in clinical trials the basic parameters of therapy need to be optimally observed, in order to make comparison of experimental arms more reliable. It is easier to achieve uniformity of technical factors in a study at a single institution than in multi-institutional cooperative groups. Thus, stringent criteria must be incorporated into the protocol describing the requirements and techniques for planning and delivery of the radiation therapy. Furthermore, the dosimetry checks carried out by the Radiological Physics Center should be an integral part of this program. In some studies it is necessary to do an initial review of dosimetry factors and portal films. This alerts the radiation oncologist to variations from the protocol and, with prompt feedback and correction of the potential error, will ensure the complete evaluability of the case. Since an increasing number of reports point out that the doses of irradiation delivered and the volume treated may affect therapeutic results, a completed case review should always be carried out. Some cooperative group studies strongly suggest a correlation between the compliance with the protocol and the results of the trial. Costs of these programs in clinical trials should be justified since, for a small investment, the evaluability rate in a protocol can be increased by 10%. The increase of patient evaluability significantly decreases the cost per evaluable patient. Furthermore, the reliability of the data of the trial will be greatly enhanced by a strong quality assurance program.

Clinical Trials as Topic↗
PubMed1983

Radiation therapy technology manpower needs 1982.

A shortage of radiation therapy technologists has existed in the United States for many years. This report analyzes the data from the third manpower survey of ACR/ASTR carried out in 1981 to 1982, using the Patterns of Care master facility list. Of 1106 questionnaires mailed, 77% were returned. The survey identified 3757 technologists performing radiation therapy technology duties. Of these, 2537 of these were Registered Technologists (Therapy) American Registry of Radiologic Technologists RTT (ARRT), 1220 were not. There has been a good growth in the total number of RTT (ARRT) members as indicated by the 1982 ARRT Annual Report (1148 in May, 1977, 2878 in May, 1982). Using the "Blue Book" Criteria of 1981 of 2 RTT/megavoltage unit or 2 RTT/300 new patients, the technology need (2900) would appear filled. However, 860 of the RTT were performing supervisory or dosimetry duties and 42% of the 2897 staff technologists were non RTT personnel. At the time of the survey, 597 funded vacancies existed (241 in 1977). A trend toward a changing standard of 3 RTT/megavoltage unit, reflecting the increased complexity of modern radiation therapy techniques, especially in Patterns of Care Strata A1, A2, C1 institutions was identified. While great progress has been made, there is a continuing need for recruitment into the 113 existing educational programs to try to stabilize the supply of technologists. Attention should also be given to measures for upgrading the skills and knowledge of the non RTT personnel in the field and retention of the RTT personnel.

Health Facilities↗
PubMed1982

Hepatitis B in homosexual men: prevalence of infection and factors related to transmission.

Of 3,816 homosexual men examined in five sexually transmitted disease clinics in the United States, 6.1% had hepatitis B surface antigen, 52.4% had antibody to hepatitis B surface antigen, and 3.0% of the men who had no other indicator of infection with hepatitis B virus (HBV) had antibody to hepatitis B core antigen. The rate of seropositivity for HBV indicated by the presence of one or more of these serologic markers was 61.5%; seropositivity was significantly related to the duration of regular homosexual activity and to the number of nonsteady male sexual contacts in the four months before the patients were interviewed. Anal-genital intercourse, oral-anal intercourse, and rectal douching were significantly related to evidence of HBV infection, but oral-oral contact and oral-genital contact were not. Trauma to the rectal mucosa is a feature common to the practices that were significantly related to seropositivity for HBV.

Adolescent↗
PubMed1981

Depression and self-esteem: an investigation that used behavioral and cognitive approaches to the treatment of clinically depressed clients.

Investigated the relative effectiveness of the behavioral and cognitive approaches to the treatment of depression using clinically depressed clients and the relationship between self-esteem and depression before and after treatment. Sixteen depressed patients matched for sex, age, and levels of depression were involved. Ss were assigned to either the cognitive or the behavioral treatment groups. Three weeks' baseline followed by 8 weeks' treatment programme was given to Ss in each group. The results of the statistical analysis show that both treatment groups are effective in alleviating depression, but the cognitive treatment group improved at a faster rate than the behavioral group. No significant correlation between self-esteem and depression was observed at baseline. However, a significant inverse correlation was observed at posttreatment and follow-up. The findings showed that both behavioral and cognitive approaches were effective in the treatment of depression. However, the cognitive approach was slightly better than the behavioral approach.

Adult↗
PubMed1981

A seroepidemiological survey in the Gezira, Sudan, with special reference to arboviruses.

A serological survey in the Gezira area of the Sudan confirmed that malaria and schistosomiasis were highly endemic. Of other parasitic infections amoebiasis was common but Toxoplasma was less than found in a previous survey. Poliomyelitis and measles infection were universal and there was an extremely high incidence of infection with hepatitis B. Of arboviruses infection with flaviviruses was frequent and more than with alphaviruses.

Adolescent↗
PubMed1981

Prosthetic valve endocarditis caused by Histoplasma capsulatum.

Previously reported cases of Histoplasma capsulatum infection of prosthetic heart valves have been first diagnosed at autopsy. A patient had an H capsulatum infection that was diagnosed by serologic means 1 1/2 years before involvement of the patient's prosthetic mitral valve was found at surgery. Numerous previous attempts to demonstrate organisms by culture and histologic study of bone marrow and liver biopsy specimens were unsuccessful. Various serologic tests were used in the diagnosis and evaluation of treatment of H capsulatum endocarditis. The management of this case was compared with 29 other previously reported cases of endocarditis caused by H capsulatum.

Adult↗
PubMed1981

Incidence of plutonium-induced bone cancer in neutered mice.

The incidence of bone cancer, after a single i.p. injection of monomeric 239Pu citrate, is significantly higher in female than in male mice. To evaluate the role of the gonads in this sex-related difference, male and female C57BL/Do (albino) mice were castrated at 40 days of age. Fifty days later, they were given injections of 239Pu. After castration, the frequency of bone sarcomas in the two sexes was approximately equal. This resulted from an increased incidence in the castrated males and a decreased incidence in the ovariectomized females as compared to the intact plutonium-treated mice.

Animals↗
PubMed1979

Immunization and health advice for international travelers.

Physicians are increasingly being called upon to advise travelers regarding health matters. Travel to virtually all parts of the world can be medically safe, given a modest investment of effort to provide appropriate immunizations and education of travelers regarding precautionary steps regarding food, drink and other matters. Instruction regarding the self administration of a few simple drugs is reasonalbe for most patients anticipating prolonged travel in tropical areas.

Beverages↗
PubMed1979

Earlier operation for left-sided Pseudomonas endocarditis in drug addicts.

Three consecutive patients with Pseudomonas endocarditis were treated by early operation with no deaths. The indications for operation were severe failure, systemic embolization, and infection refractory to antibiotics. The organism is aggressive, characterized by early invasion of the myocardium. Wide débridement of the anulus is necessary to remove any vegetations or intramyocardial abscessed wall. Because multiple valve infection is common, it is important to evaluate all four cardiac valves at the time of operation. Removing a second rim of the mitral anulus for separate culture at the time of mitral valve replacement may demonstrate the degree to which the valve resection has removed all infection. Early operation is necessary for reinfection of the prosthetic valve; however, metastatic abscess should also be considered in the face of continued signs of infection postoperatively. Patients should receive a 6 week postoperative course of antibiotics which have been shown by in vitro testing to be serum bactericidal in at least a 1:8 dilution. The operative findings of invasion of the myocardium by the organism and the surgical success in this small series have resulted in our recommending earlier operation in patients with these indications.

Adult↗
PubMed1978

Urethral reaction to catheter materials in dogs.

The reaction of the urethra to two new polyurethrane polymers was compared with those produced by materials currently used in the manufacture of urethral catheters. The comparison included silicone, latex rubber, tetrafluoroethylene polymer (Teflon) coated latex, and polyvinyl chloride. There were no significant differences in the reaction of the urethra to the various materials. The present study was carried out in the absence of bacterial contamination.

Animals↗