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Biomedical subjects

D Jacobs

Publications and source records attributed to D Jacobs.

At least 73 records · Page 4Linked to original sources
PubMed1995

Application of PCR for detection and identification of mycoplasma contamination in virus stocks.

A nested polymerase chain reaction (PCR) was used to detect and identify mycoplasma contaminants in viral stocks. The results of the PCR assay proved to be a sensitive and accurate indicator of the true status of the stock tested. Those samples positive by agar culture or Hoechst stain were also positive by PCR. Those samples that were inconclusive by Hoechst stain (10.05%) could be clearly determined to be mycoplasma positive or negative by PCR. The PCR assay also detected those fastidious species of mycoplasma that gave false negative results by the direct culture method. In many respects the PCR-based mycoplasma detection method described is superior to the agar culture and Hoechst staining detection methods. In this study, the PCR assay detected substantially more mycoplasma-positive viral stocks than did the agar culture assay. Due to its speed, sensitivity, and reliability, the PCR assay is of particular value in monitoring the process of removing mycoplasma from contaminated stocks. Furthermore, the PCR amplification products can be analyzed by restriction analysis to rapidly identify the species of the mycoplasma contaminating the stock tested.

Base Sequence↗
PubMed1995

Clinical evaluation of hexagonal keratotomy for the treatment of primary hyperopia.

We evaluated the effectiveness of spiral hexagonal keratotomy in correcting primary hyperopia in 199 eyes. One hundred eighty-four eyes (92.5%) had a minimum follow-up of three months. Mean follow-up was 11.9 months and maximum, 36.2 months. Secondary astigmatic keratotomy was performed on 54 eyes six to eight months after initial hexagonal surgery to correct induced astigmatism. The mean reduction in spherical equivalent was -1.6 +/- 0.9 diopters (D) (range -5.6 to +0.9 D). The mean increase in refractive cylinder was +0.5 +/- 0.9 D (range -2.3 to +3.0 D). Uncorrected acuity improved by +3.2 lines, while best corrected acuity decreased slightly by -0.26 lines. Loss of two or more lines of best corrected acuity that was attributable to surgery was between 0.5% and 4.0%.

Adult↗
PubMed1995

Cellular and humoral immune responses to recombinant antigens in sheep infected with Toxoplasma gondii.

Immune responses to recombinant fragments of the Toxoplasma gondii antigens ROP2 and GRA2 were investigated in sheep naturally and experimentally infected with T. gondii oocysts. Specific serum antibodies to C-terminal fragments were detected by ELISA. Cell-mediated responses in peripheral blood mononuclear cells were demonstrated by proliferation and interferon-gamma production following in vitro stimulation with the ROP2 fragment. This data indicates the presence of epitopes for sheep B cells in the recombinant GRA2 fragment and for both B and T cells in the ROP2 fragment.

Animals↗
PubMed1995

Genetic diversity and phylogeny of toxic cyanobacteria determined by DNA polymorphisms within the phycocyanin locus.

Cyanobacteria are a highly diverse group in relation to form, function, and habitat. Current cyanobacterial systematics relies on the observation of minor and plastic morphological characters. Accurate and reliable delineation of toxic and bloom-forming strains of cyanobacteria has not been possible by traditional methods. We have designed general primers to the phycocyanin operon (cpc gene) and developed a PCR which allows the amplification of a region of this gene, including a variable intergenic spacer sequence. Because of the specificity of this PCR for cyanobacterial isolates, the assay is appropriate for the rapid and reliable identification of strains in freshwater samples. Successive restriction endonuclease digestion of this amplification product, with a total of nine enzymes, yielded many identifying DNA profiles specific to the various taxonomic levels of cyanobacteria. The restriction enzyme profiles for MspI, RsaI, and TaqI were conserved for strains within each of the eight genera (40 strains) studied and clearly discriminated among these genera. Intrageneric delineation of strains was revealed by the enzymes AluI, CfoI, and HaeIII for members of the genus Microcystis, while strains of genus Anabaena were differentiated by the digestion patterns provided by AluI, CfoI, and ScrFI. Phenetic and cladistic analyses of the data were used to infer the genetic relatedness and evolution of toxic and bloom-forming cyanobacteria.

Base Sequence↗
PubMed1995

Enterobacterial repetitive intergenic consensus sequences and the PCR to generate fingerprints of genomic DNAs from Vibrio cholerae O1, O139, and non-O1 strains.

Enterobacterial repetitive intergenic consensus (ERIC) sequence polymorphism was studied in Vibrio Cholerae strains isolated before and after the cholera epidemic in Brazil (in 1991), along with epidemic strains from Peru, Mexico, and India, by PCR. A total of 17 fingerprint patterns (FPs) were detected in the V. cholerae strains examined; 96.7% of the toxigenic V. cholerae O1 strains and 100% of the O139 serogroup strains were found to belong to the same FP group comprising four fragments (FP1). The nontoxigenic V. cholerae O1 also yielded four fragments but constituted a different FP group (FP2). A total of 15 different patterns were observed among the V. cholerae non-O1 strains. Two patterns were observed most frequently for V. cholerae non-01 strains, 25% of which have FP3, with five fragments, and 16.7% of which have FP4, with two fragments. Three fragments, 1.75, 0.79, and 0.5 kb, were found to be common to both toxigenic and nontoxigenic V. cholerae O1 strains as well as to group FP3, containing V. cholerae non-O1 strains. Two fragments of group FP3, 1.3 and 1.0 kb, were present in FP1 and FP2 respectively. The 0.5-kb fragment was common to all strains and serogroups of V. cholerae analyzed. It is concluded from the results of this study, based on DNA FPs of environmental isolates, that it is possible to detect an emerging virulent strain in a cholera-endemic region. ERIC-PCR constitutes a powerful tool for determination of the virulence potential of V. cholerae O1 strains isolated in surveillance programs and for molecular epidemiological investigations.

Bacterial Toxins↗
PubMed1995

Who comes to a voluntary depression screening program?

OBJECTIVE: The purpose of this study was to describe who comes to a voluntary depression screening program by analyzing findings from the 1992 National Depression Screening Day. METHOD: Survey results from 5,367 adult volunteers at 345 facilities were analyzed. The authors examined the prevalence of depression detected at the screening test and sociodemographic characteristics and treatment history of the respondents. They also estimated the percentage of these individuals who would actually have a diagnosis of major depression (positive predictive value). The main assessment measure was the Zung Self-Rating Depression Scale. RESULTS: Of all participants, 76.6% (N = 4,109) had at least minimal depressive symptoms (score of at least 50 on the Zung depression scale), 53.3% (N = 2,859) had at least moderate symptoms (score of at least 60), and 22.6% (N = 1,214) had severe symptoms (score of at least 70). Few of the depressed respondents were currently in treatment for a mental health problem. The positive predictive value of a screening test diagnosis of depression was between 92.5% and 95.5% when a cutoff score of 60 was used to indicate depression and between 88.7% and 92.3% when a cutoff score of 50 was used. CONCLUSIONS: Voluntary screening tests, as exemplified by results from the National Depression Screening Day, provide a good opportunity for identifying previously unidentified and untreated individuals with depression.

Adolescent↗
PubMed1995

The psychological autopsy: a useful tool for determining proximate causation in suicide cases.

This overview article examines the applications of the psychological autopsy method in determining proximate causation in suicide cases. The article reviews the history of the psychological autopsy and describes its procedure and how it has proved helpful in explicating proximate causation. The five standards currently used by the courts to determine proximate causation in suicide cases are described, as are a variety of applications of the psychological autopsy method, including its application to workers' compensation cases, product liability cases, and medical malpractice cases. In particular, issues of prediction and protection are addressed. Finally, there is a discussion of an application of the psychological autopsy to criminal cases. The article concludes with a discussion of the issues raised in the use of the psychological autopsy during expert testimony and the considerations that should be addressed by an expert witness contemplating the use of the psychological autopsy method.

Adolescent↗
PubMed1994

Surgical management of the osteoradionecrotic mandible with free vascularised composite flaps.

Osteoradionecrosis (ORN) of the mandible is a serious sequel to radiotherapy administered for malignant neoplasms of the head and neck. In a retrospective/prospective study, 28 patients with mandibular defects due to ORN were reviewed. Monocortical and bicortical defects as well as pathological fractures were reconstructed by means of a free serratus anterior/rib (n = 8) or a vascularised iliac crest flap (n = 25). All the former survived; a pathological fracture, however, occurred postoperatively in 2 of the patients (25%). Five iliac crests were lost (20%). The remaining bone struts healed well. The donor site morbidity was very low. Clinical and radiological longterm follow-up showed that a very acceptable functional and cosmetic result was achieved in all cases. Progress of ORN was prevented in ca. 90% of all patients. The radiological follow-up was facilitated with the use of high-resolution CT-scans.

Adult↗
PubMed1994

Verbal memory performance of patients with human immunodeficiency virus infection: evidence of subcortical dysfunction. The HNRC Group.

In the present study, the California Verbal Learning Test (CVLT) was administered to symptomatic HIV+ (n = 31), asymptomatic HIV+ (n = 94), and HIV-normal control (HIV-NC) (n = 40) subjects to assess the prevalence and nature of their verbal memory deficits. Symptomatic HIV+ subjects were significantly impaired relative to HIV-control subjects on CVLT measures of acquisition and retention, and were significantly less likely than control subjects to use a semantic clustering strategy to support recall. The performance of the asymptomatic HIV+ subjects fell between those of the symptomatic HIV+ subjects and HIV-controls on almost every CVLT measure. A linear discriminant function analysis (DFA) was used to compare the performances of these three groups to Alzheimer's disease (AD). Huntington's disease (HD), and normal control (NC) subjects on three CVLT measures, including total recall over five learning trials, intrusion errors, and a derived score of delayed recognition discriminability minus the final learning trial. Significant differences were found between the number of symptomatic HIV+ subjects classified as HD (32%), AD (3%), and normal (65%), the number of asymptomatic HIV+ subjects classified as HD (16%), AD (1%), and normal (83%), and the number of HIV-NC subjects classified as HD (2%), AD (0%), and normal (98%). The profile of verbal memory deficits exhibited by the subgroup of impaired HIV+ subjects was similar to that of patients with HD, a prototypical subcortical dementia, and different from that of patients with AD, a prototypical cortical dementia. This finding is consistent with reports of the predominance of subcortical neuropathological changes associated with HIV infection.

AIDS Dementia Complex↗
PubMed1994

Age at onset of Alzheimer's disease: relation to pattern of cognitive dysfunction and rate of decline.

We examined the pattern of cognitive impairment and rate of cognitive and functional decline as a function of age at symptom onset in 127 patients with probable Alzheimer's disease (AD). At baseline, early-onset (before age 65) and late-onset groups were mildly and comparably impaired on the modified Mini-Mental State Examination (mMMS) and the Blessed Dementia Rating Scale-Part 1 (BDRS). Repeated-measures analysis of variance revealed significantly more rapid decline in early-onset subjects over a 2-year follow-up period. Multivariate linear regression analyses indicated that age at symptom onset strongly predicted rate of decline on the mMMS and the BDRS, even after controlling for symptom duration, gender, family history of dementia, and baseline mMMS and BDRS scores. Early- and late-onset AD subjects also differed in terms of pattern of performance on the mMMS. Early-onset subjects scored significantly lower than late-onset subjects on attentional items of the mMMS at baseline and follow-up. Conversely, late-onset subjects scored significantly lower than early-onset subjects on memory and naming items at baseline, and the two groups were comparable on these tasks at follow-up. Results provide longitudinal evidence of more rapid cognitive and functional decline in subjects with early-onset AD and suggest that early-onset AD may be characterized by predominant impairment of attentional skills.

Age of Onset↗
PubMed1994

A study of the reliability and comparative validity of the cardia dietary history.

This study evaluated the reliability and comparative validity of the dietary history survey method developed for CARDIA, a longitudinal investigation of life-styles and the evolution of cardiovascular risk factors in young adults. The method was tested in a sample of 30 white men, 33 white women, 33 black men, and 32 black women, aged 18 to 35 years, in four regions reflecting the race, sex, age, and geographical distribution of CARDIA participants. For 64 of the participants, two dietary history interviews, 1 month apart, were conducted by trained nutritionists. These data were used to examine the reliability of the method. For all participants, seven telephone- assessed 24-hour dietary recalls were randomly scheduled during a 28-day period and were followed by a dietary history interview. These data were used to examine the comparative validity of the method. Calories, total fat, saturated fat, polyunsaturated fat, monounsaturated fat, dietary cholesterol, protein, carbohydrate, alcohol, potassium, calcium, and vitamin A were selected by the CARDIA Nutrition Working Group as the nutrients for comparison. Mean nutrient values from the first history tended to be higher than those obtained from the last history. However, for a majority of the nutrients, the differences were significant for blacks but not for whites. The correlations for the log-transformed nutrient values and calorie-adjusted nutrient values from the two histories were generally in the range of 0.50 to 0.80 for whites. For blacks, the correlations were lower, with a majority in the range of 0.30 to 0.70. The average nutrient values estimated from the histories were higher than those estimated from the average of the seven 24-hour recalls. The differences in blacks were larger than in whites. For both the log-transformed nutrient values and the calorie-adjusted nutrient values, the correlations between the two methods were generally larger than 0.50 for whites. However, for blacks, the correlations were lower, and for several macronutrients, the correlations were close to zero. These results suggest that the CARDIA dietary history is a reasonably reliable and valid dietary survey method for obtaining information about habitual intakes in whites. In blacks, the results are less consistent. The black-white differences remained when the analyses were stratified by education. These results raise a question about differences in reporting between blacks and whites.

Adolescent↗
PubMed1994

Changes in measurements of body fat distribution accompanying weight change.

The waist-to-hip circumference ratio (WHR), as an indicator of body fat distribution is related to several clinical diseases. Whether one can reduce this ratio with weight loss is still unconfirmed and may differ between sexes. The degree to which WHR changes with weight gain is also unclear. Changes in waist and hip circumferences and WHR accompanying changes in weight over 5 years were examined in 3,753 black and white men and women initially ages 18-30. Those who gained weight increased their WHR and in most cases those whose weight remained stable increased their WHR. Those who gained the most weight had the greatest increases in WHR. Men had greater increases in WHR per kg weight gain than women. In general, weight loss was accompanied by a decrease in the WHR. However, in those whose initial WHR was below the median, weight loss was associated with an increase in WHR. Smokers and black males also had increases in WHR with weight losses up to 4.9 kg.

Adipose Tissue↗