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Biomedical subjects

J Griffith

Publications and source records attributed to J Griffith.

At least 181 records · Page 10Linked to original sources
PubMed1985

Association of M13 I-forms and spheroids with lipid vesicles.

Electron microscopy and density gradient centrifugation were used to demonstrate that the coat protein of M13 I-forms and spheroids, but not of filaments, can form some type of association with lipid vesicles in vitro. The association was detected only when the phage particles were incubated with dilauroylphosphatidylcholine (DLPC) or dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles (SUV) above the phase transition temperature of the lipid. Under these conditions the I-form coat protein was resistant to proteolytic digestion, and the viral DNA was also associated with the vesicles.

Capsid↗
PubMed1985

Grower reported pesticide poisonings among Florida citrus fieldworkers.

In a 1981 survey of 436 Florida citrus growers, 27 pesticide related poisoning incidents were reported that were to have taken place within one year of the interview date. From these reports it is possible to estimate that there are 376 citrus fieldworker related poisonings per year in Florida. This number of estimated poisonings may be developed into an incidence rate of 113 fieldworker poisonings per 10,000 fieldworkers.

Agricultural Workers' Diseases↗
PubMed1985

Pesticide poisonings reported by Florida citrus fieldworkers.

In a 1981 survey of 1811 Florida citrus fieldworkers, 25 pesticide related poisoning incidents involving 29 fieldworkers were reported. Suspected poisonings were categorized into possible and confirmed poisonings, and from these reports it was possible to project an estimated 438 possible poisonings, and 73 confirmed poisonings among all citrus fieldworkers. Confirmed pesticide poisonings were developed into an incidence rate of 34 poisonings per 10,000 permanent and semi-permanent fieldworkers. The number of possible and confirmed poisonings, for all fieldworkers, was then developed into an incidence rate of 160 poisonings per 10,000 fieldworkers.

Adolescent↗
PubMed1985

Monitoring study of urinary metabolites and selected symptomatology among Florida citrus workers.

A cross-sectional monitoring study was made of citrus fieldworkers employed during an entire citrus growing season in Florida. A survey questionnaire was administered to 1811 fieldworkers employed as applicators, mixers, loaders, tractor drivers, general combination workers, and pickers on 436 citrus groves throughout Florida. The study was designed to evaluate exposure to organophosphorus pesticides by analyzing the urine of citrus fieldworkers for dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP), dimethyl dithiophosphate (DMDTP), diethyl phosphate (DEP), diethyl thiophosphate (DEPT), and diethyl dithiophosphate (DEDTP), and to relate the findings to the reported occurrence of selected health symptoms associated with pesticide intoxication. Urine samples were collected for analysis from 332 spray-season workers and 265 harvest-season workers. Measurable DEP residue values were found in 68% of the spray season workers and 43% of the harvesters. However, with the exception of DEP and DETP values in the urine of spray-season workers, metabolite residues were low, often at, or just above, detection limits (which were usually 0.02 ppm but occasionally rose higher, with a few at 0.03 ppm and a very few at 0.04 ppm). Although there was clearly exposure to organophosphates among the citrus fieldworkers, there was no apparent association between the reported health symptoms and the relatively low levels of organophosphate metabolites found in the urine of the workers.

Agricultural Workers' Diseases↗
PubMed1985

New data from the Addiction Severity Index. Reliability and validity in three centers.

The Addiction Severity Index (ASI) is a clinical/research instrument which has been in wide use during the past 6 years to assess the treatment problems found in alcohol- and drug-abusing patients. In a study of male veterans, a preliminary evaluation of the ASI has indicated reliability and validity. The present report presents an expanded examination of these issues; 181 subjects from three treatment centers were studied. Results of concurrent reliability studies indicate that trained technicians can estimate the severity of patients' treatment problems with an average concordance of .89. Test-retest studies show that the information obtained from the ASI is consistent over a 3-day interval, even with different interviewers. Comparisons of the ASI severity ratings and composite measures with a battery of previously validated tests indicate evidence of concurrent and discriminant validity. The reliability and validity results were consistent across subgroups of patients categorized by age, race, sex, primary drug problem, and treatment center. The authors discuss the strengths and limitations of the instrument based upon 5 years of use. The overall conclusion is that the ASI is a reliable and valid instrument that has a wide range of clinical and research applications, and that it may offer advantages in the examination of important issues such as the prediction of treatment outcome, the comparison of different forms of treatment, and the "matching" of patients to treatments.

Adult↗
PubMed1984

Emotional support providers and psychological distress among Anglo- and Mexican Americans.

Accumulating evidence from studies investigating the role naturally-occurring emotional support networks play in remediating psychological distress strongly suggests that such networks buffer personal distress and lessen the need for formal mental health care. Research findings also suggest that reliance on emotional support networks varies across ethnic groups. The present study compared emotional support network characteristics of Anglo-Americans to those of Mexican Americans, in addition to examining the relationship between the reliance on specific support providers and psychopathological symptoms for Anglo- and Mexican Americans. Randomly selected adult Anglo- and Mexican Americans (n = 515) living in one of three suburban communities in Southern California provided responses to a standardized measure of psychological impairment and named those persons on whom they depended in time of personal problems. Both Anglo- and English speaking Mexican American (ES MA) respondents reported significantly larger networks and more cumulative contact and reciprocity with network members than did Spanish-speaking Mexican Americans (SS MA) respondents. Anglos and ES MAs named significantly more friends and neighbors as emotional support providers than did SS MAs. SS MAs, on the other hand, more often depended on extended kin and spouses than did the other two subgroups. Professional caregivers accounted for a very small proportion of responses across the subgroups. The number of friends and neighbors as support providers was significantly and positively correlated with problems of social relations in only the SS MA subgroup. Implications of results for community mental health direct and indirect service components are discussed.

Adult↗
PubMed1984

Electron microscopy can be used to measure DNA supertwisting.

We have examined the use of electron microscopy (EM) to measure the degree of supertwisting of covalently closed circular fd and pBR322 DNAs. Band counting agarose gel electrophoresis was used to quantitate the number of twists in these DNAs. DNA species having moderate-to-low superhelical densities were prepared by treatment of the DNA with Drosophila topoisomerase 1 in the presence of ethidium bromide (EtBr) followed by isolation of discrete DNA topoisomers from preparative gels. These DNAs were then examined by EM using a direct mounting method employing a buffer containing spermidine. The crossovers in individual DNA molecules were counted and compared to the supertwist values obtained from gel studies. The results show that EM can provide a reliable estimate of the number of supertwists in DNAs having low-to-moderate superhelical densities.

DNA Topoisomerases, Type I↗
PubMed1984

The psychiatrically severe drug abuse patient: methadone maintenance or therapeutic community?

The present research was conducted to examine the effects of pretreatment psychiatric status and treatment duration on improvement following drug abuse rehabilitation. Percent improvement from admission to 6-month follow-up was measured on three criteria: drug use, employment, and criminality. Analyses of the total samples in both the Therapeutic Community (TC) and Methadone Maintenance (MM) programs indicated some quantitative differences between the two modalities but all measures showed a strong and positive relation between treatment duration and percent improvement. When patients in the two program samples were divided, on the basis of admission psychiatric status, into LOW, MID, and HIGH severity groups, different findings emerged. LOW severity patients in both programs showed the greatest absolute levels of improvement in most measures, more improvement at shorter treatment durations, and less additional improvement at longer treatment durations. MID severity patients in both programs showed the most dramatic effects of treatment duration, with generally large improvements in all criteria at greater treatment lengths. Qualitatively different results were seen between the treatment programs for the HIGH severity patients. HIGH severity MM patients showed low absolute levels of improvement but longer treatment durations were associated with modest improvements. HIGH severity TC patients also showed low absolute levels of improvement but unlike any other group, greater lengths of treatment were associated with negative change (worsened status) across all measures. The authors discuss these results with regard to the general efficacy of drug-dependence treatment and the specific issue of the psychiatrically impaired drug abusers.

Adult↗
PubMed1984

Bus training for developmentally disabled adults.

The effectiveness of a program combining classroom and community training in the teaching of bus-riding skills to developmentally disabled adults. These skills were taught sequentially using questions about a slide presentation, role playing, and performance in the natural environment. The experimental design was based upon the work of Neef, Iwata, and Page (1978). Test trials were conducted after each phase of training. Results showed that all subjects learned the necessary bus-riding skills and maintained their performance throughout the follow-up period of at least 1 year. The combination training method proved to be efficient and cost effective.

Activities of Daily Living↗
PubMed1984

Nelson's syndrome after Cushing's disease in childhood: a continuing problem.

Nelson's syndrome--progressive cutaneous hyperpigmentation with x-ray film evidence of an expanding pituitary tumor--is now a well-recognized sequela of bilateral adrenalectomy for Cushing's disease. It is estimated to occur in 8% to 38% of adults. Because Cushing's disease is rare in children, a higher incidence of Nelson's syndrome has not been suggested until recently. Although transsphenoidal operation is now the treatment of choice for Cushing's disease, children who have undergone bilateral adrenalectomy remain at risk for the development of Nelson's syndrome. A review of our experience and the literature indicates that the incidence of Nelson's syndrome after the treatment of Cushing's disease is higher in children than in adults. In our six children who underwent adrenalectomy between 8 and 17 years of age, four developed Nelson's syndrome at 2, 6, 10, and 12 years after adrenalectomy. Two of these patients remain well at 6 and 9 years after treatment with external irradiation. One patient treated with external irradiation developed recurrence at 5 years and required total hypophysectomy. The fourth patient required total hypophysectomy followed by external irradiation. Of the 37 patients reviewed and analyzed, the mean age at diagnosis of Cushing's disease was 12 years, with a mean interval of 8.4 years between adrenalectomy and Nelson's syndrome. Information regarding treatment for Nelson's syndrome was known in 24 patients and included pituitary irradiation (four patients), pituitary operation (11 patients), pituitary irradiation followed by operation (six patients), and pituitary operation followed by irradiation (three patients).

Adolescent↗
PubMed1984

Procedure development. A simplified approach.

A step-by-step guide for writing procedures/protocols in an easy-to-read, standardized format is presented. The guidelines emphasize clarity, accessibility, and directness to provide an efficient method of producing finished and effective procedures that enhance performance.

Humans↗
PubMed1983

The structure of recA protein-DNA filaments. 2 recA protein monomers unwind 17 base pairs of DNA by 11.5 degrees/base pair in the presence of adenosine 5'-O-(3-thiotriphosphate).

recA protein binds to duplex DNA in the presence of Mg2+ and adenosine 5'-O-(3-thiotriphosphate) forming a stiff nucleoprotein filament with a distinct axial repeat which contains 17 +/- 1 base pairs and spans 8-9 nm along the fiber (Di Capua, E., Engel, A., Stasiak, A., and Koller, Th. (1982) J. Mol. Biol. 157, 87-103; Dunn, K., Chrysogelos, S., and Griffith, J. (1982) Cell 28, 757-765). Measurement of the protein:DNA ratio in these filaments utilizing double label analysis and isopycnic density banding shows that there are 2 recA monomers for every 17 base pairs. The DNA is also partially unwound in this filament. Utilizing the recA-induced relaxation of naturally supertwisted SV40 DNA, we show that the DNA is unwound by 11.5 +/- 1.5 degrees/base pair which corresponds to 180-200 degrees for each repeat unit along the filament length.

Adenosine Triphosphate↗
PubMed1983

Coat protein conformation in M13 filaments, I-forms and spheroids.

Circular dichroism studies of the filamentous coliphage M13 were carried out to determine conformational changes in the major capsid protein (the B protein) that occur during contraction of the filaments to I-forms and spheroids. The alpha-helicity of the B protein is somewhat lower in the I-forms than in filaments and much lower in spheroids. This conformational change may explain the increased detergent and lipid solubility of both I forms and spheroids relative to filaments.

Capsid↗
PubMed1983

A comparison of bupropion, dextroamphetamine, and placebo in mixed-substance abusers.

The subjective, behavioral, and physiological effects of bupropion, a nontricyclic antidepressant, were compared with those of dextroamphetamine and placebo in a randomized double-blind crossover study. The volunteers who participated were multiple-drug abusers. Six acute drug treatments, three doses of bupropion (100, 200, 400 mg), two doses of dextroamphetamine (15, 30 mg), and placebo were administered orally at intervals of not less than 72 h. Results indicated that the subjective effects of amphetamine as measured by the Addiction Research Center Inventory (ARCI) differed markedly from bupropion and placebo. Bupropion, in contrast to amphetamine, had no peripheral sympathomimetic effects and did not reduce appetite or caloric intake.

Adult↗
PubMed1983

Mapping restriction sites on large DNAs by electron microscopy.

We have developed a novel technique to map restriction sites on large duplex DNAs by electron microscopy. In this method, the sample DNA is first cut with a restriction enzyme. The resulting fragments are briefly digested with Escherichia coli exonuclease III, and treated with wheat germ RNA polymerase II to fill-in with RNA the resulting gaps. These small RNAs, complementary to sequences immediately adjacent to either side of the restriction site, are isolated from the DNA template and R-looped to the full-length DNA. When this material is prepared by the formamide-cytochrome spreading technique, small bubbles are visible wherever there is a restriction site on the DNA. Improved methods of mapping are outlined.

Bacteriophage lambda↗