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Biomedical subjects

A Huda

Publications and source records attributed to A Huda.

16 recordsLinked to original sources
PubMed2004

Longitudinal study of interferon-gamma, serum antibody and milk antibody responses in cattle infected with Mycobacterium avium subsp. paratuberculosis.

During a 2-year study period, 252 animals from dairy herds infected with Mycobacterium avium subsp. paratuberculosis, and 119 animals from non-infected herds were subjected to repeated blood and faecal sampling. Animals were retrospectively grouped by infection status as infected, exposed (culture negative animals from infected herds), or non-infected animals, and by age, 12-23 months (1+ year), 24-35 months (2+ years), or 36 months and older (3+ years). Samples were collected for culture of faeces, assessment of interferon-gamma (IFN-gamma) secreted by M. paratuberculosis antigen stimulated whole-blood lymphocytes (IFN-gamma test), and measurement of antibody responses against M. paratuberculosis in serum and milk by an in-house absorbed ELISA. The IFN-gamma test diagnosed higher proportions of infected and exposed animals than the antibody ELISAs. The highest sensitivity of IFN-gamma test was in infected cattle of 2+ years of age. Receiver-operating characteristic (ROC) analyses supported the assumption that the IFN-gamma test had a better performance than antibody tests of animals of 1+ and 2+ years of age. However, for animals of 3+ years all tests performed equally well. Application of single sampling compared with repeated samplings showed better performance of the IFN-gamma test by repeated samplings, and the milk antibody ELISA in animals of 3+ years of age performed significantly better with repeated sampling compared with single sampling. In conclusion, the IFN-gamma test may be applied for screening of cattle of 1 and 2 years of age for exposure to M. paratuberculosis and the antibody ELISAs from 3 years of age.

Age Factors↗
PubMed2003

Analysis of repeated tests for interferon-gamma (IFN-gamma) response and faecal excretion for diagnosis of subclinical paratuberculosis in Danish cattle.

A total of 315 cattle were tested for infection with Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) at three consecutive samplings, using the interferon-gamma (IFN-gamma) test on whole blood and bacteriological culture of faecal samples. Of 205 cattle from 10 infected herds 99 (48%) were positive in the IFN-gamma test on at least one sampling using "IDEXX-criteria" for interpretation, and of 110 cattle from five non-infected herds three (3%) were positive. Forty-four animals from infected and one from non-infected herds tested positive at all three samplings. Although support for the specificity of the IFN-gamma test was provided by these results, they also indicate problems with false positives. Approximately half of the positive animals did not give the same result at all three samplings, indicating that repeated testing increases the chance of detecting reactors. Changing, or fluctuating, IFN-gamma test results occurred most frequently in animals younger than 1 year, indicating that the IFN-gamma test should be applied only to animals 1 year and older. M. paratuberculosis was isolated from 16 (4%) of 371 cattle, all from infected herds. Fifteen culture-positive cattle tested positive at least once in the IFN-gamma test. It was not possible to predict from the IFN-gamma test result the number of animals that would eventually develop disease. However, the test may be useful to detect animals that have been exposed to M. paratuberculosis earlier in their lives, and the testing of young cattle could be included in a control program to check for the effectiveness of preventing transmission of infection to calves and to identify animals at risk of developing disease later in their lives.

Animals↗
PubMed2003

Comparison of histopathology, cultivation of tissues and rectal contents, and interferon-gamma and serum antibody responses for the diagnosis of bovine paratuberculosis.

The diagnosis of infection with Mycobacterium avium subsp. paratuberculosis was studied in 12 cattle from infected dairy herds and four from non-infected herds. A comparison was made of (1) histopathological examination and bacterial culture of tissues, (2) culture of serial samples of rectal contents, and (3) examination of repeated blood samples for interferon-gamma (IFN-gamma) and antibody responses. Tissue samples were taken from the small and large intestine and corresponding mesenteric lymph nodes, and from the pharyngeal tonsil and other lymphoid nodes (retropharyngeal, mediastinal, hepatic and supramammary). Histopathological examination and bacterial culture of tissues each revealed that six of the 16 cattle were infected, whereas repeated culture of rectal contents revealed only five infected animals. Except for the hepatic lymph node of a single animal, culture-positive tissues were confined to the intestinal tract and related lymph nodes. Bacterial culture of tissues from the ileum, caecum and lymph nodes draining the jejunum revealed the highest number of infected animals. Moreover, slightly greater numbers of positive tissues were revealed by culture than by histopathological examination. For both the IFN-gamma response and the antibody response, the means of the values for the final three samples before slaughter were significantly higher in infected than in non-infected cattle. However, these immunological responses were too variable to provide a reliable indication of infection.

Animals↗
PubMed2002

Interpretation of the gamma interferon test for diagnosis of subclinical paratuberculosis in cattle.

A group of 252 cattle without clinical signs of paratuberculosis (paraTB) in 10 herds infected with paraTB and a group of 117 cattle in 5 herds without paraTB were selected. Whole-blood samples were stimulated with bovine, avian, and johnin purified protein derivative (PPD) and examined for gamma interferon (IFN-gamma) release. For diagnosis of paraTB, satisfactory estimated specificities (95 to 99%) could be obtained by johnin PPD stimulation irrespective of interpretation relative to bovine PPD or no-antigen stimulation alone, but numbers of test positives in the infected herds varied from 64 to 112 with different interpretation criteria. For a limited number of test-positive animals, no change in the test results could be observed with increasing antigen concentrations but IFN-gamma responses were significantly reduced (P < 0.0001) and four out of seven reactors tested negative when stimulation was performed on day-old samples. Denmark is free of bovine tuberculosis, but cross-reactivity with paraTB could be documented for cattle more than 14 months old in paraTB-infected herds compared with those in non-paraTB-infected herds. In both paraTB-free and paraTB-infected herds, false positives were observed when the test was applied to calves less than 15 months of age. Until novel antigen formulations more specific for these diseases are available, interpretation of the IFN-gamma test must be individually adjusted to fit specific needs and the context within which the test is applied and, for paraTB, the test seems most appropriate for use as a supportive tool for evaluation of disease-preventive measures in young stock.

Animals↗
PubMed2000

Differences between Danish bovine and human Staphylococcus aureus isolates in possession of superantigens.

PCR-assays for the detection of staphylococcal enterotoxins A-E, and H, toxic shock toxin 1, and exfoliative toxins A and B were evaluated against phenotypic methods, and performed well. Four hundred and fourteen isolates of Staphylococcus aureus from Danish cases of bovine mastitis were screened for genes encoding these superantigens. One hundred isolates from Danish human carriers were also included in the study. In contrast to the frequent presence of genes encoding and in vitro expression of superantigens among the human carrier isolates, only one of 414 isolates from bovine mastitis carried the genes encoding enterotoxin C and toxic shock toxin-1. These results further support the hypothesis that the bovine and human S. aureus reservoirs constitute two separate sub-populations of the species S. aureus. The results also show that these superantigens are generally not present in Danish S. aureus isolates from bovine mastitis, and thus play no essential role in the pathogenesis of bovine S. aureus mastitis.

Animals↗
PubMed1998

Evolution of compliance within a fall prevention program.

When evaluating the effectiveness of a fall prevention program, it is useful to first determine whether the program is being uniformly administered. Members of a medical-surgical unit's Quality Assurance/Product Improvement Team studied both processes as well as outcomes over a two-year implementation of a fall prevention program. They discovered that initial attempts at implementation underestimated the quantity of resources necessary to ensure full implementation of the program. This article chronicles the series of audits and program modifications that eventually brought about success to this unit.

Accidental Falls↗
PubMed1998

Cerebral 1H MR spectroscopy and neuropsychologic status of patients with hepatic encephalopathy.

OBJECTIVE: Our objective was to assess the metabolite levels (myo-inositol [ml], choline [Cho], creatine [Cr], glutamate or glutamine [Glx], and N-acetyl-L-aspartate [NAA]) visible on 1H MR spectroscopy in patients with subclinical and mild hepatic encephalopathy before and after liver transplantation and to correlate these data with the results of neuropsychiatric tests and related clinical findings. SUBJECTS AND METHODS: A stimulated-echo sequence was used to localize a single voxel in the parietal region. Seventeen patients and 13 healthy volunteers were investigated. Nine of the 17 patients also were investigated after liver transplantation. A battery of neuropsychologic tests also was administered to patients to assess frontal, memory, and motor functions. RESULTS: Before liver transplantation, significant reductions in mI:Cr (51%) and Cho:Cr (11%) and a significant increase in Glx:Cr (20%) were observed in patients compared with the respective ratios in healthy subjects. Patients also were significantly impaired on neuropsychologic tests measuring frontal and motor performance, but not memory. Impairment on the frontal index showed a significant correlation with mI:Cr levels; likewise, performance on the motor index showed a significant correlation with serum ammonia levels before transplantation. MR spectroscopy after liver transplantation showed changes in the metabolite ratios compared with the pretransplantation status. Even though the Glx:Cr ratios decreased after transplantation, the mI:Cr ratio remained lower than those of healthy subjects. CONCLUSION: The relationship of changes in the metabolite ratios recorded from a voxel in the posteromedial parietal lobe to the neuropsychologic findings before and after liver transplantation is a major finding.

Adult↗
PubMed1998

Identification of Prototheca from bovine mastitis in Denmark.

In the present study, algal isolates recovered during the period 1991 through 1996 from Danish cases of bovine mastitis were characterized and identified. Sixteen isolates of Prototheca were obtained, all of which were identified as Prototheca zopfii according to assimilation pattern, absence of capsules and resistance to clotrimazole.

Animals↗
PubMed1998

Bovine mammary protothecosis due to Prototheca zopfii.

Mastitis due to Prototheca zopfii was diagnosed in three of 28 cows in a dairy herd. As two cows continued to shed algae after 45 days they were slaughtered and organs were examined by cultivation, histology, immunohistochemistry and electron microscopy. Algae were restricted to the mammary glands and regional lymph nodes in which a granulomatous inflammation was seen. Algae were predominantly seen in macrophages but neutrophils also contained organisms. In macrophages both sporangiospores and sporangia were found, suggesting that intracellular proliferation may be responsible for the failure to overcome the infection. Serum samples from all cows were assayed for antibodies against P. zopfii in an enzyme-linked immunosorbent assay (ELISA). Although the highest titre was found in an infected cow the difference between the mean values of the titre in infected and non-infected cows was not significant.

Animals↗
PubMed1994

Decommissioning of a university research reactor.

The objective of the UCLA Boelter Reactor Decommissioning Project was the release of the Boelter reactor facility for unrestricted use. The facility included a 100 kW Argonaut type research reactor that operated from 1963 to 1985, providing general reactor research. The decommissioning was planned as a two-phase program. Phase I involved removal of the reactor core structure for better access and assessment of the biological shield. Phase II decommissioning activities included structural steel removal, activated concrete removal, process equipment pit piping dismantlement, and clean concrete removal. The final release survey of the Boelter reactor facility demonstrated that all areas satisfied the project's release criteria. The total person-Sv for the project was 3.87 x 10(-2) (3.87 person-rem), most of which was received during the structural steel and activated concrete removal tasks and the disassembly of the reactor core.

Los Angeles↗
PubMed1994

Mycotic and algal bovine mastitis in Denmark.

A one-year examination of mammary secretions (n = 2,896) from Danish cattle with clinical or subclinical mastitis revealed 45 strains of fungi and algae. The strains originated from 44 mammary secretions of 42 cows in 40 herds. The following species of fungi were identified: Candida catenulata (n = 2), Candida kefyr (n = 6), Candida krusei (n = 17), Candida rugosa (n = 6), Candida tropicalis (n = 3), Candida valida (n = 1), Geotrichum capitatum (n = 5). The algal species Prototheca zopfii was demonstrated in five samples.

Animals↗
PubMed1994

Risk factors for transmission of Streptococcus agalactiae infection between Danish dairy herds: a case control study.

A group of 152 Danish dairy herds infected with Streptococcus agalactiae during 1992 was compared with 177 randomly selected control herds in order to identify factors of importance for the transmission of this bacteria between herds. The diagnosis was based on a laboratory microbiological test on a bulk tank milk sample, and management information was collected by telephone interviews with the farmers. Results from logistic regression clearly indicate that purchase of cows or heifers increases the risk of a new Streptococcus agalactiae herd infection. Hygiene management risk factors inside the farm were also identified.

Analysis of Variance↗
PubMedDate not supplied

Clinical correlation of neuropsychological tests with 1H magnetic resonance spectroscopy in hepatic encephalopathy.

OBJECTIVE: The purpose of this project was to correlate neuropsychological test results with in vivo measures of regional cerebral biochemistry determined by 1H MRS in patients with subclinical and mild hepatic encephalopathy. METHODS: Baseline 1H MRS scans and neuropsychological testing of patients occurred at entry into the study. The primary localized volume chosen for the 1H MRS study was the posteromedial parietal cortex, which consisted predominantly of white matter. Some of these patients were scanned again if they received a liver transplantation. In a subset of patients, the effect on cerebral biochemistry and neuropsychological test performance due to a dietary intervention of reduced protein intake was monitored. These patients underwent a baseline examination and a repeat examination after 2 weeks of dietary intervention. Measures were made of the correlation between the dietary intervention and 1H MRS determined biochemistry and the results of neuropsychological tests. Results in both patient groups (dietary intervention and no dietary intervention) were compared with healthy control subjects. RESULTS: Subclinical and low grade HE patients showed a significant reduction in mI/Cr and Cho/Cr ratio when compared with healthy control subjects. These patients also showed impairment in frontal lobe mediated cognitive tasks and in motor ability that were not appreciated in a bedside examination. The patients did not return to normal cerebral metabolic states within 30 to 60 days of liver transplantation. In fact, reductions remained in mI/Cr. Cho/Cr values increased after transplantation compared with healthy control subjects. CONCLUSIONS: 1H MRS studies showed changes in regional cerebral biochemistry associated with all grades of HE. There was a reduction in mI/Cr and a reduction in Cho/Cr in patients with low grade and subclinical forms of HE compared with normal subjects. The reduction in mI correlated well with abnormalities observed in neuropsychological tests. Liver transplantation was not associated with significant improvement in these variables.

Acetylcholine↗