Biomedical subjects

J Brandt

Publications and source records attributed to J Brandt.

At least 145 records · Page 8Linked to original sources

PubMed1999

The current epidemiological status of bovine theileriosis in eastern Zambia.

Results of a longitudinal study conducted in the eastern province of Zambia from 1994 to 1997 indicate that it is doubtful whether a state of endemic stability of East Coast fever (ECF) can be reached in the near future. Even in endemic areas, the mortality of Theileria parva infections is still estimated above 50%. The main factors limiting progress towards endemic stability are high innate susceptibility of the Zebu cattle, the virulence of the parasite and the climate. The unimodal rainfall pattern results in restricted activity of Rhipicephalus appendiculatus instars and year-to-year variation in rainfall causes fluctuations in tick phenology and T. parva transmission. Adult tick activity invariably peaks during the rains and is associated with the highest ECF incidence. Nymphal transmission of T. parva to cattle appears to be less important. Second periods of activity of both adult and nymphal instars are pronounced only when the climate is suitable. These second waves of tick activity ensure a more continuous and efficient transmission of T. parva and also play a key role in the dynamics of prolonged outbreaks in epidemic areas. ECF control methods may have an important influence on ECF epidemiology. Immunizations as well as chemotherapy of clinical cases create a reservoir of virulent parasites in susceptible cattle, resulting in artificial endemic stability.

Animals↗

PubMed1999

Upgrade to dual chamber pacing after long-term ventricular stimulation: feasibility and intermediate term follow-up.

AIMS: To evaluate the feasibility and follow-up results of atrial lead implantation and a change to dual chamber pacing following long-term treatment with single chamber ventricular stimulation. METHODS AND RESULTS: During a 30-month period, 70 consecutive patients with ventricular pacemakers were referred for pulse generator exchange or lead reoperation. Using defined criteria, an upgrade procedure was considered indicated in 34 of the cases (49%); these patients had a mean age of 74.8+/-8.8 years, and had been treated with VVI or VVIR pacing for a mean time of 7.8+/-3.8 years (range 1.8-17). An atrial lead was successfully implanted via ipsilateral subclavian venipuncture through the existing pectoral pacemaker pocket in 33 of the 34 cases (97% of the attempts). Postoperatively, one atrial lead dislodgement was seen, and another patient required atrial lead adjustment due to P wave undersensing. The mean follow-up period was 14+/-10 months. During this time, four patients developed permanent atrial fibrillation (annual incidence 11%. In 82% of the patients in whom an upgrade procedure was attempted, dual chamber pacing was maintained at the end of follow-up. CONCLUSION: Restoration of AV synchrony is possible in a substantial proportion of patients treated with long-term ventricular stimulation. Atrial lead placement through ipsilateral subclavian venipuncture is generally feasible, and the vast majority of cases remain in dual chamber pacing with normal function during intermediate term follow-up.

Aged↗

PubMed1999

Autologous tendons used as grafts for bridging peripheral nerve defects.

This study was performed to investigate whether autologous collagen and other extracellular matrix components could be used in nerve repair by bridging a 10 mm defect in the rat sciatic nerve. Three models of repair were examined. In the first model, a rat tail tendon was teased and subsequently rolled to form a loose collagen roll which was sutured over the defect. In the second model, an intact tendon was used. In the third model, a teased tendon was pretreated with attachment of nerve segments to each end for 4 weeks before grafting. Both teased and intact tendons supported regeneration, to some extent. Pretreatment resulted in migration of Schwann cells into the graft, and enhanced regeneration.

Animals↗

PubMed1999

Consequences of premature discontinuation of the developmental test of visual-motor integration: can these tests be salvaged?

The administration of many neuropsychological tests includes discontinuation criteria that are often complex and time-consuming. As a result, it is not uncommon for an examiner to unintentionally discontinue the administration of a test prematurely. This investigation of 56 correctly scored Developmental Test of Visual-Motor Integration protocols was conducted to determine how the premature termination of this particular test significantly affects its overall score, and thus, its interpretation. These data indicate that premature discontinuation of this test results in a minimal loss of points overall, and thus, does not invalidate the interpretation of its score.

Alzheimer Disease↗

PubMed1999

Construct and concurrent validity of the Hopkins Verbal Learning Test-revised.

The present investigation examined the validity of the revised Hopkins Verbal Learning Test (HVLT-R). In a principal components analysis with varimax rotation, measures of new learning and delayed recall loaded on a single factor distinguishable from measures related to general cognitive function and visual memory. The HVLT-R also correlated most strongly with other tests of verbal memory and relatively weakly with a test of general intelligence. Group comparisons showed that normal controls performed better than age- and education-matched patients with probable Alzheimer's disease (AD) or vascular dementia (VaD). Discriminant function analyses and Bayesian statistics revealed high classification accuracies for dementia patients versus controls. When scores on the HVLT-R and other neuropsychological tests were subjected to discriminant function analyses, performance on the HVLT-R delayed recognition task was found to be the most useful in discriminating patients with AD from those with VaD. We conclude that the HVLT-R is a valid test of verbal learning and memory that is best suited for use with elderly patients suspected of dementia.

Aged↗

PubMed1999

Anterograde and retrograde memory in children anesthetized with propofol.

Prior to anesthesia with propofol for gastrointestinal endoscopy, sets of pictures were presented to 20 children and adolescents (M age = 12 years). Word pairs (e.g., "hiking-woods") were presented via earphones after the children were anesthetized. Upon regaining consciousness, the children were tested for explicit memory of both the picture sets and word pairs by free recall, cued recall, and yes/no recognition. Implicit memory was tested by free association to category cues for the pictures and by word association for the word pairs. Postoperative testing revealed retrograde memory for material presented preoperatively but total amnesia for material presented intraoperatively. There was no evidence of implicit memory for material not available explicitly. The finding of uninterrupted ability to retain and retrieve information presented prior to anesthesia despite total anterograde amnesia has implications for preoperative communication directed toward pediatric patients as well as for intraoperative communication among surgical staff.

Adolescent↗

PubMed1999

Reduced basal ganglia blood flow and volume in pre-symptomatic, gene-tested persons at-risk for Huntington's disease.

The aim of this study was to examine basal ganglia volumes and regional cerebral blood flow in asymptomatic subjects at-risk for Huntington's disease who had undergone genetic testing. We determined which measures were the best 'markers' for the presence of the mutation and for the onset of symptoms. Twenty subjects who were Huntington's disease gene mutation-positive and 24 Huntington's disease gene mutation-negative participants, all of whom had a parent with genetically confirmed Huntington's disease, and were therefore 50% at-risk for inheriting the Huntington's disease gene mutation, were included in the study. To evaluate basal ganglia structure and function, MRI and single photon emission computed tomography (SPECT) were used. Quantitative measures of regional volumes and relative measures of regional perfusion were calculated. SPECT and MRI scans were co-registered so that MRI anatomy could be used accurately to place SPECT regions. Estimated years-to-onset in the mutation-positive subjects was calculated based on a regression formula that included gene (CAG)(n) repeat length and parental age of onset. Changes in imaging measures in relation to estimated years-to-onset were assessed. The imaging measure that was most affected in mutation-positive subjects was putamen volume. This was also the measure that correlated most strongly with approaching onset. In subjects >/=7 years from estimated onset age, the putamen volume measures were similar to those of the mutation-negative subjects. However, in subjects </=6 years from estimated onset age, there were dramatic reductions in putamen volume, resulting in >90% discrimination from both the far-from-onset and the mutation-negative subjects. Caudate volume and bicaudate ratio also showed a significant decline in the close-to-onset subjects, although to a lesser degree than putamen volume reductions. Furthermore, SPECT basal ganglia perfusion deficits were observed in mutation-positive subjects. Imaging markers of neuropathological decline preceding clinical onset are important for assessing the effects of treatments aimed at slowing the course of Huntington's disease. The current study suggests that quantitative assessment of basal ganglia may provide a means to track early signs of decline in individuals with the Huntington's disease gene mutation prior to clinical onset.

Adult↗

PubMed1999

Association between executive attention and physical functional performance in community-dwelling older women.

OBJECTIVES: Executive functions supervise the contents of working memory, where information from long-term memory is integrated with information in the immediate present. This study examined whether executive attentional abilities were uniquely associated with the performance of complex, instrumental activities of daily living (IADLs) in cognitively intact and physically high-functioning older women. METHODS: Participants were 406 community-residing, older women aged 70-80 years in the Women's Health and Aging Study (WHAS) II, screened to be physically high functioning and cognitively intact using the Mini-Mental State Exam. Hierarchical regression models, adjusted for demographic and disease variables, were used to evaluate the association of cognitive domains, including executive attention, memory, psychomotor speed, and spatial ability with summary measures of IADL (e.g., looking up and dialing a telephone number) and mobility-based ADL (e.g., walking 4 meters) function. RESULTS: Tests of executive attention were associated with performance on IADLs (6.6%) and, to a lesser degree, mobility-based ADLs (1%), adjusting for demographic and disease variables. In particular, the mental flexibility component of the Trail Making Test accounted for the majority of attentional variance in IADL performance. Older age, lower education, and African American race were also associated with poorer physical test performances. DISCUSSION: Executive difficulties in flexibly planning and initiating a course of action were selectively associated with slower performance of higher-order IADL tests, relative to other domains of cognition, in a high-functioning, community-based older cohort. These results suggest that executive functions may be important in mediating the onset and progression of physical functional declines.

Activities of Daily Living↗

PubMed1999

Studying patients with inflammatory back pain and arthritis of the lower limbs clinically and by magnetic resonance imaging: many, but not all patients with sacroiliitis have spondyloarthropathy.

OBJECTIVE: Clinical and magnetic resonance imaging (MRI) data of 170 consecutive patients with inflammatory back pain (IBP) and/or oligoarthritis of the lower limbs were evaluated in a retrospective study. The aim was to determine the frequency of sacroiliitis and spondyloarthropathy (SpA) in this population, and to assess the significance of HLA B27 measurements for diagnosis in early disease. METHODS: Pelvic X-rays were performed in all IBP patients and dynamic MRI of the sacroiliac joints in patients with IBP who had indefinite results on sacroiliac X-rays (n = 32). RESULTS: European Spondyloarthropathy Study Group criteria for SpA were fulfilled by 106/170 patients (62.4%); eight additional patients had symptoms suggestive of SpA (4.7%). The most frequent SpA subset was undifferentiated SpA (uSpA), diagnosed in 46/106 patients (43.4%). Sacroiliitis was detected by MRI in 21/32 patients with IBP and unclear X-rays (65.6%). Of those, 14 were diagnosed as SpA and seven females with moderate unilateral sacroiliitis, but no features of SpA, also not on follow-up (at least 1 yr), were classified as undifferentiated sacroiliitis (US). Ten of the 14 SpA (71.4%) and none of the seven US patients were HLA B27 positive. CONCLUSION: HLA B27 positivity in IBP patients with MRI-proven sacroiliitis positively predicts SpA. uSpA is a frequent SpA subset. There are HLA B27-negative non-SpA patients with moderate unilateral sacroiliitis whom we propose to be classified as US.

Adult↗

PubMed1999

The General Medical Health Rating: a bedside global rating of medical comorbidity in patients with dementia.

OBJECTIVE: Dementia is a serious public health problem. General medical comorbidity is common in dementia patients and critical to their care. However, little is known about medical comorbidity in these patients, and there are no straightforward bedside global rating scales for the seriousness of comorbid medical illness. This paper describes the development and measurement properties of the General Medical Health Rating (GHMR), a rapid global rating scale of medical comorbidity in dementia patients. DESIGN: Interrater reliability, concurrent validity, and predictive validity of the GMHR are reported. SETTING: An outpatient dementia clinic, assisted living, and nursing home. PARTICIPANTS: A total of 819 consecutive dementia clinic outpatients and 180 consecutive admissions to Copper Ridge, a long-term care residence for people with dementia, were included in the study. RESULTS: GMHR was found to be highly reliable (weighted kappa = .91). Across all stages and types of dementia, GMHR ratings were correlated with number of comorbid medical conditions, number of medications being taken for comorbid conditions, and with activity of daily living impairment, even after adjustment for severity of dementia. GMHR ratings were also a strong predictor of falls and of mortality in long-term care residents after adjustment for age and severity of dementia. CONCLUSION: GMHR is a reliable, valid, global bedside measure of severity of general medical comorbidity for patients with dementia that can be used for clinical and research purposes.

Accidental Falls↗

PubMed1999

Universal pattern of RpoB gene mutations among multidrug-resistant isolates of Mycobacterium tuberculosis complex from Africa.

SETTING: Multidrug-resistant tuberculosis (MDR-TB) presents an increasing burden in Southern Africa. Rapid diagnostic tests for drug resistance to rifampicin have been developed based on mutation analysis of the rpoB gene. However, geographic differences of underlying mutations have recently been suggested. OBJECTIVE: Drug-resistant strains of Mycobacterium tuberculosis complex from Africa were analysed for geographic differences in frequency and location of rpoB mutations. DESIGN: A random sample of rifampicin-resistant strains was collected from 87 patients with pulmonary MDR-TB treated in 12 hospitals from six different regions of South Africa. In addition, 18 isolates of M. tuberculosis complex from Namibia, Sierra Leone, and Uganda, including 13 isolates of M. africanum, were analyzed. Point mutations were detected by direct sequence analysis of the rpoB gene. RESULTS: Missense mutations were identified for 91 isolates (87%). Double mutations were present in eight (8%) MDR-TB isolates, two of which carried one mutation outside a previously described diagnostic region. We found no geographic differences regarding the frequency and pattern of single rpoB gene mutations. CONCLUSION: Our results confirm that molecular genetic analysis of rifampicin resistance based on a core region within the rpoB gene is universally applicable to strains of M. tuberculosis complex from different geographic regions.

Africa↗

PubMed1999

Thermal instability of the trimeric structure of the N-terminal propeptide of human procollagen type I in relation to assay technology.

The N-terminal propeptide of procollagen type I (PINP) appeared in two peaks after size chromatography. The high-molecular weight form was transformed to the low-molecular weight form during incubation at 37 degreesC, whereas the low-molecular weight form remained unchanged. The PINP concentrations in amniotic fluid and sera remained unchanged during 37 degreesC incubation when measured using an ELISA; however, concentrations decreased by 89-93% when measured using an RIA. The ELISA:RIA ratio varied from 1.1 to 2.9 in these fluids because of different size distributions and the inability of the RIA to measure the low-molecular weight form. Thermal transition of the high-molecular weight form caused a change in its elution volume but did not change its migration in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mass spectrometry revealed identical results for both forms. We reached the following conclusions: (a) the trimeric structure of PINP is unstable at 37 degreesC; (b) the two molecular forms represent intact alpha1 chains in trimeric and monomeric forms; (c) thermal transition is an ongoing in vivo process; and (d) this is important in the choice of assay technology.

Amniotic Fluid↗

PubMed1998

A sensitive and specific 30-min Dot-ELISA for the detection of anti-leishmania antibodies in the dog.

A very rapid, sensitive and specific Dot-ELISA was developed for diagnosing visceral leishmaniosis in dogs infected with Leishmania infantum. Sera from 26 healthy dogs and 127 dogs with different infectious disease including 40 dogs with leishmaniosis, and 87 dogs with other suspected or confirmed infectious diseases, was evaluated in an alkaline phosphatase ELISA on a nitrocellulose membrane, sensitized with soluble promastigote antigen. The test procedure lasted only 30 min. Distinction between leishmania positive and leishmania negative sera was complete at a dilution of 1/320, hence there was no cross-reactivity, not even with sera from dogs with trypanosomal or babesial infections. Therefore, it is concluded that this test has a very high sensitivity and specificity for the detection of anti-leishmania antibodies in the dog. The Dot-ELISA was significantly positive correlated with the direct agglutination test (DAT), the indirect immunofluorescence test (IFAT), and the Slide-ELISA. A significant concordance of the four tests was also demonstrated.

Agglutination Tests↗

PubMed1998

Ten-year disease free survival after transperineal sonography-guided iodine-125 brachytherapy with or without 45-gray external beam irradiation in the treatment of patients with clinically localized, low to high Gleason grade prostate carcinoma.

BACKGROUND: The authors report observed 10-year brachytherapy results in the treatment of 152 consecutive patients with clinically organ-confined prostate carcinoma. METHODS: One hundred and fifty-two consecutive patients with T1-T3, low to high Gleason grade, prostate carcinoma were treated between January 1987 and June 1988 at Northwest Hospital in Seattle, Washington. Their median age was 70 years (range, 53-92 years). Of these 152 patients, 98 (64%) received an iodine-125 implant alone (Group 1), and the remaining 54 patients (36%), who were judged to have a higher risk of extraprostatic extension, also were treated with 45 gray (Gy) of external beam irradiation to the pelvis (Group 2). No patient underwent lymph node sampling, and none received androgen ablation therapy. Multivariate regression and the Mann-Whitney rank sum test were used for statistical analysis. Preoperative patient data with associated success or failure outcomes at 10 years after treatment were used for training and validating a back-propagation neural network prediction program. RESULTS: The average preoperative prostate specific antigen (PSA) value, clinical stage, and Gleason grade were 11.0 ng/mL, T2, and 5, respectively. The median posttreatment follow-up was 119 months (range, 3-134 months). Overall survival 10 years after treatment was 65%. At last follow-up only 3 of the 152 patients (2%) had died of prostate carcinoma. Ninety-seven patients (64%) remained clinically and biochemically free of disease at 10 years of follow-up and had an average PSA value of 0.18 ng/mL (range, 0.01-0.5 ng/mL). In these patients a period of 42 months was required to reach the average PSA (0.5 ng/mL). The median to last PSA follow-up was 95 months (range, 3-134 months). Postoperative needle biopsies were negative in 56% of patients, positive in 15% of patients, and not available in 29% of patients. Only 6% of patients developed bone metastasis. At 10 years there was no statistically significant difference in treatment outcome between patients who received iodine-125 alone, and those who received iodine-125 with 45-Gy external beam irradiation (P = 0.08). Nevertheless, in these two groups preoperative PSA, stage, and Gleason grade were significantly different (P < 0.01). In the artificial neural network analysis, pretreatment serum PSA was the most accurate predictor of disease-free survival. CONCLUSIONS: Percutaneous prostate brachytherapy is a valid and efficient option for treating patients with clinically organ-confined, low to high Gleason grade, prostate carcinoma. Observed 10-year follow-up documents serum PSA levels superior to those reported in several published external beam irradiation series, and comparable to those published in a number of published radical prostatectomy series.

Aged↗

PubMed1998

Interleukin-12 enhances the virus-specific interferon gamma response of pigs to an inactivated pseudorabies virus vaccine.

Cell-mediated immunity is a major component of the host defense system against viral infections. Since interleukin (IL)-12 has been shown to be a potent stimulus for the in vivo generation of interferon-gamma (IFN-gamma)-producing T cells (i.e. Th-1 cells) in laboratory animals, we evaluated the effect of IL-12 on the cellular immune response of pigs to vaccination against pseudorabies virus (PrV), a herpesvirus of swine. The magnitude of the cellular immune response was measured by IFN-gamma ELISPOT analysis of peripheral blood mononuclear cells (PBMC) from pigs which had been immunized twice, at 2-week intervals, with either, modified live virus (MLV) alone or with a commercial inactivated PrV vaccine with or without the coadministration of human recombinant IL-12 (HrIL-12). No significant differences in the titer of virus-neutralizing antibodies or in the intensity of the virus-specific lymphoproliferative response among the different treatment groups was observed. However, the number of virus-specific IFN-gamma-producing cells among PBMC isolated from animals receiving the MLV vaccine was on average 3.5 times more than animals immunized with the inactivated vaccine (P = 0.01). Administration of the inactivated vaccine and IL-12 induced a two-fold higher frequency of virus-specific IFN-gamma-producing cells from that induced by the inactivated vaccine alone (P < 0.05). Despite this enhancement, the level of protection from lethal PrV challenge provided by the inactivated vaccine in combination with IL-12 was the same as that induced by the inactivated vaccine alone. Both of these vaccination regimes provided significantly lower levels of protection than those afforded by the MLV vaccine. This study demonstrates that an inactivated PrV vaccine is a poor inducer of virus-specific IFN-gamma-producing cells and that this response can be enhanced by administration of exogenous IL-12. The data provides evidence of a dichotomy in the humoral and cellular immune responses of pigs to a viral antigen and implies the existence of a Th-1/Th-2 type regulation of the anti-viral immune response in pigs.

Adjuvants, Immunologic↗

PubMed1998

Improved detection of circulating antigen in cattle infected with Taenia saginata metacestodes.

In order to improve the sensitivity and the specificity of an existing IgM monoclonal antibody-based ELISA (Brandt et al., 1992) for the detection of circulating antigen in the sera of cattle infected with T. saginata metacestodes, a modified sandwich ELISA was developed. Monoclonal antibodies (MAbs) of the IgG isotype were produced against the excretory-secretory (ES)-products of T. saginata metacestodes. Since it was shown that the affinity of these IgG MAbs for ES antigen was higher than that of the IgM MAbs, the latter were replaced by two IgG1 MAbs (158C11 and 60H8). Furthermore, heat treatment of the sera significantly increased the OD-values of ES-spiked serum samples as compared to nontreated samples. It also decreased the number of false positive reactions. When the original IgM MAb-based ELISA was compared with the IgG MAb-based ELISA using heat treated sera from animals harbouring more than 50 living metacestodes of T. saginata, the sensitivity increased from 56% with the former to 92% with the latter assay. Only a small percentage of animals carrying less than 50 cysts were detected both with the ELISA using IgG or IgM MAbs. The specificity of the IgM- and IgG MAb-based ELISAs was 93.4% and 98.7% respectively.

Animals↗

PubMed1998

A study of the efficacy of a comprehensive memory enhancement program in healthy elderly persons.

Well educated, high functioning older adults (ages 60-90) were given a comprehensive memory enhancement training program to determine the effectiveness of the program in increasing cognitive performance and positively influencing self-assessments of memory efficacy. The 68 subjects who participated in the memory enhancement training were compared to 74 subjects who were enrolled in a video control group. Between subject differences were analyzed prior to the interventions and at three time points following the interventions (immediately post, 3 months and 6 months). Only one cognitive measure, assessing verbal memory, revealed a significant difference between the groups, with participants in the memory enhancement group showing less decline from baseline than the video control group immediately following the intervention but with no difference between groups at 6 months post-intervention. Several self-report measures showed that the memory enhancement training subjects experienced improved memory functioning and decreased memory concerns relative to the video control group. The self-reported effects of the training were sustained over the 6-month follow-up period.

Adult↗

PubMed1998

Quantification of the N-terminal propeptide of human procollagen type I (PINP): comparison of ELISA and RIA with respect to different molecular forms.

This paper compares the results of procollagen type I N-terminal propeptide (PINP) quantification by radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA). PINP in serum from a patient with uremic hyperparathyroidism was measured in RIA and ELISA to 20 micrograms l-1 and 116 micrograms l-1 and the corresponding concentrations in dialysis fluid were 94.5 micrograms l-1 and 140 micrograms l-1, respectively. PINP antigen appears in two distinct peaks following size chromatography and the two peak fractions display immunological identity and identical M(r)'s (27 kDa: SDS-PAGE). Analysis of fractions from size separated amniotic fluid, serum and dialysis fluid demonstrated that the RIA failed to measure the low molecular weight form of PINP. However, the anti-PINP supplied with the RIA-kit and the anti-PINP applied in the ELISA reacted equally well with both molecular forms of PINP when analysed in a direct ELISA. It is concluded that the major difference in the ELISA and RIA results is due to assay efficacy with respect to the low molecular weight form of PINP.

Amniotic Fluid↗