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Biomedical subjects

K Abbott

Publications and source records attributed to K Abbott.

At least 19 recordsLinked to original sources
PubMed2004

Pathological calcification in juvenile dermatomyositis (JDM): microCT and synchrotron x-ray diffraction reveal hydroxyapatite with varied microstructures.

The objective of this study was to begin to relate the microstructure of calcinosis samples to clinical and laboratory characteristics of the juvenile dermatomyositis (JDM) patients. Laboratory x-ray microCT (micro-Computed Tomography) noninvasively mapped microstructure for the first time in JDM calcifications. Synchrotron x-ray diffraction (transmission geometry) identified the mineral phase and crystallite size in the deposits. Samples were obtained from four children who had active JDM longer than 80 months and who were typed for TNFalpha-308 allele polymorphisms. Uniform mineral (giving the appearance of an extruded solid) was observed in one patient, and irregular blocks of differing sizes filled the samples from two other patients. The sample from the fourth patient appeared to combine features of the other two types. These spatial distributions of mineral were quite different from those in a bone reference sample. The only mineral observed in the JDM samples was hydroxyapatite (HAP), and the diffraction peaks of the JDM samples were slightly narrower than those of a trabecular bone reference sample. Diffraction peak widths of the JDM specimens revealed crystallite sizes (approximately 220-240 A) that are comparable to values reported in the literature for bone. Three children were positive for TNFalpha-308 GA polymorphism. The data suggest several possible origins for blocky vs. uniform structure of the JDM calcifications, including differences in duration of untreated inflammation, in TNFalpha-308 polymorphism, and in mechanical constraint at the calcification site. Information from additional samples is required to determine the relative role of each of these factors. Taken together, non-invasive microCT and x-ray diffraction characterization on the same samples offer an informative window into the dystrophic mineralization process in JDM.

Adolescent↗
PubMed2004

Field evaluation of tracer sheep for the detection of early natural infection with Mycobacterium avium subsp paratuberculosis.

OBJECTIVE: To determine whether tracer sheep could be used to detect S strain Mycobacterium avium subsp paratuberculosis on pasture, and to provide further insight into the early stages of infection. DESIGN: A field study on two farms in an endemic area for ovine Johne's disease in New South Wales. Procedure Lambs, weaners and adult ewes were introduced to pasture with varying amounts of M. a. paratuberculosis contamination and monitored using skin tests, gamma interferon assay, faecal culture and serial necropsy of small groups for up to 15 months after first exposure. RESULTS: Culture from tissues was the most sensitive method for detecting early infection in sheep after natural exposure to S strain M. a. paratuberculosis. The organism was detected in at least one introduced sheep from every exposed group, 6 to 12 months after first exposure. Histopathological lesions were detected in only 17% of culture-positive sheep, and only after at least 8 months of exposure. Similarly, antemortem diagnostic tests had low sensitivity during the early stages of naturally acquired infection. There was no evidence of any differences in infection rate between sheep first exposed as neonates, as weaners or as adults. A higher proportion of lambs born to ewes from an infected flock were infected than lambs suckling uninfected ewes introduced to the same infected environment, and infection was detected earlier in these 'resident' lambs. CONCLUSION: These findings indicate that groups of unexposed 'tracer' sheep, tested by culture of tissues at slaughter 6 to 12 months after first exposure, might be a useful way to assess pasture infectivity in control programs for ovine Johne's disease.

Animals↗
PubMed2001

Rotavirus encephalopathy: pathogenesis reviewed.

Two cases of rotavirus gastroenteritis associated with neurological involvement, one with encephalitis (defined by abnormal neurological signs, cerebrospinal fluid (CSF) pleocytosis and detection of rotavirus genomic nucleic acid in the CSF) and one with a non-inflammatory encephalopathy (defined by abnormal neurological signs, an entirely normal CSF and detection of rotavirus genomic nucleic acid in the CSF), are presented and used as a basis to review and explore potential pathogenetic mechanisms, including direct viral replication within neurons and indirect effects of the newly described rotavirus 'enterotoxin'.

Acyclovir↗
PubMed1997

A treatment for tardive dyskinesia and some other extrapyramidal symptoms.

The effects of the administration of acetazolamide and thiamine (A + T) on the symptoms of tardive dyskinesia (TD) and parkinsonism of 8 elderly and 25 younger chronic hospitalized mental patients were examined in a placebo-controlled, double-blind, counterbalanced two-period cross-over study with initial baselines and intervening washout periods. All patients were maintained on their prestudy psychoactive and anti-Parkinson medications, without alteration, throughout the study. The elderly group received 1.5 g acetazolamide and thiamine per day in three divided doses for 3 weeks. The younger group received 1.5 g thiamine and 2.0 g acetazolamide per day in divided doses for 2 months. Both groups showed a significant decrease in scores on the Abnormal Involuntary Movement Scale (TD) and the Simpson-Angus Neurological Rating Scale (parkinsonism) while on A + T. The A + T effects were unrelated to age, gender, diagnosis, or maintenance medications.

Acetazolamide↗
PubMed1996

Effects of dihydropyridine calcium antagonists on albuminuria in patients with diabetes.

The present study was designated to assess the effects of two different dyhydropyridine calcium antagonists (DHPCAs) on proteinuria in patients with noninsulin-dependent diabetes mellitus (NIDDM). The hypothesis that similar levels of blood pressure reduction with two different DHPCAs produce similar degrees of proteinuria reduction was tested. In a prospective randomized study, 14 patients with NIDDM, hypertension, proteinuria, and renal insufficiency were given either isradipine (n = 7) or nifedipine XL (n = 7) for 6 months. After a 2-week washout period, patients were crossed over to the other drug and observed for an additional 6 months. Drugs were titrated to lower arterial pressure to < 140/90 mmHg. Patients also instructed to follow a low-sodium diet at the initial visit. Blood pressure and 24-hour urine values for creatinine clearance, albuminuria, proteinuria, and sodium were assessed monthly. At the end of the initial and crossover treatment periods, there were no significant reductions in the level of albuminuria from baseline with either drug. Sodium excretion was < 110 mEq/L with each drug tested. The results of this study support the concept that DHPCAs do not reduce proteinuria in patients with type II diabetes. This failure to reduce albuminuria and proteinuria occurred despite adequate blood pressure reduction and an effort at dietary sodium restriction.

Adult↗
PubMed1995

The use of a topical refrigerant anesthetic to reduce injection pain in children.

Early childhood experiences with painful injections may lead to anxiety and fear. These reactions need not develop if steps are taken to reduce the pain associated with injections. The purpose of this study was to assess the efficacy of a refrigerant topical anesthetic in reducing injection pain in preschool children experiencing routine diphtheria-pertussis-tetanus (DPT) immunizations. This double-blind placebo-controlled study was conducted in community health clinics in conjunction with ongoing immunization programs. Ninety subjects, aged 4-5.5 years, were randomly assigned to one of three groups: (a) refrigerant topical anesthetic; (b) placebo topical spray; and (c) no-spray control. Pain was measured subjectively using a four-point visual analogue scale. Both the refrigerant topical anesthetic spray and the placebo spray significantly reduced injection pain. Age was found to be an important factor influencing pain response in this study. Parental anxiety was not a significant factor influencing pain response. In addition, parents were not good at predicting their child's pain. The results of the study support the use of an intervention, such as refrigerant topical anesthetic, as a practical, simple, and effective treatment strategy for reduction of short-term painful procedures like injections.

Administration, Topical↗
PubMed1995

Outcomes of hand surgery. British Society for Surgery of the Hand.

The findings are presented of a conference on Outcomes of Hand Surgery organized by the audit committee of British Society for Surgery of the Hand in 1993. Measures of outcome in terms of movement, power, sensibility, pain, activities of daily living, complications and patient satisfaction are considered, and an example of a patient evaluation measure given as an appendix.

Adult↗
PubMed1995

Reliability of differential PCR for the detection of EGFR and MDM2 gene amplification in DNA extracted from FFPE glioma tissue.

A series of 43 human gliomas, consisting of 30 glioblastomas, 7 anaplastic astrocytomas, 3 low grade astrocytomas, 2 ependymomas, and 1 oligodendroglioma, was studied for amplification of the epidermal growth factor receptor (EGFR) and mouse double minute 2 (MDM2) genes. DNA extracted from formalin-fixed, paraffin-embedded tissue sections was analyzed by differential PCR and the results were compared with slot blot examination of DNA extracted from frozen tissue from the same neoplasms. Twelve glioblastomas (40%) showed amplification of the EGFR gene, and overexpression of EGFR was evident in each of these tumors as indicated by the immunoperoxidase technique. Two of the tumors with EGFR gene amplification also revealed amplification of the MDM2 gene, while one additional glioblastoma revealed MDM2 amplification only. A 100% concordance in the detection of amplification was observed between differential PCR and slot blot analysis; consequently, these results indicate that differential PCR using DNA extracted from archival tissue sections is a reliable method of demonstrating gene amplifications in glial tumors.

Adult↗
PubMed1994

University-college collaboration: rethinking curriculum development in nursing education.

The behavioral approach to curriculum development is inadequate to educate nurses to practice in the future health care system. As a result of a government initiative, a Canadian university and four community colleges had an opportunity to collaborate on development of a nursing program and thereby consider alternative approaches to curriculum development. This paper describes the process used to develop this curriculum and provides an overview of the curriculum development model that emerged. A community development process characterized by a commitment to be futuristic and visionary about nursing while making curriculum decisions was established. The curriculum model that emerged used a phenomenological exploration of our common vision for nursing in the future. The resulting curriculum is based on a human science paradigm that encourages nurses to work from a health promotion perspective with an ethic of caring.

British Columbia↗
PubMed1993

Y chromosome loss in esophageal carcinoma: an in situ hybridization study.

Carcinoma of the esophagus shows a strong male predominance and other epidemiologic differences from cancers arising at other sites. In this study, the prevalence of Y chromosome loss in 29 carcinomas of the esophagus and 53 carcinomas arising elsewhere in the aerodigestive tract was assessed by in situ hybridization of formalin-fixed paraffin-embedded tissue sections. Absence of the Y chromosome was defined as (1) negative staining for Y in neoplastic cells with positive staining for Y in immediately adjacent nonneoplastic epithelial and stromal cells, (2) positive staining of neoplastic cells with control probes for chromosomes X and 17, and (3) similar results at different stringencies and levels of protein digestion. According to these criteria, absence of the Y chromosome was observed in 13 of 14 (93%) adenocarcinomas of the esophagus, 8 of 13 (62%) squamous cell carcinomas of the esophagus, and 5 of 53 (9%) carcinomas arising in other sites. For the neoplasms examined, Y chromosome deletion was strongly and selectively associated with carcinomas, particularly adenocarcinomas, of the esophagus (P < .0001). These findings suggest that Y chromosome loss may be pathogenetically significant in these neoplasms.

Adenocarcinoma↗
PubMed1993

Mutations in the p53 gene in human astrocytomas: detection by single-strand conformation polymorphism analysis and direct DNA sequencing.

The p53 gene was examined in a series of formalin-fixed paraffin-embedded astrocytic neoplasms of various types by polymerase chain reaction (PCR), single-strand conformation polymorphism analysis (SSCP), and direct sequencing of amplified DNA. PCR primers were designed to amplify three DNA fragments encompassing exons 5, 7, and 8 with splice sites, including all four mutational "hot spots" within this gene. SSCP was performed in a polyacrylamide gel containing 10% glycerol. Two mutations were found among the 20 high and intermediate grade adult astrocytomas studied by this sensitive screening technique and confirmed by sequencing of the PCR product. (1) An anaplastic astrocytoma disclosed a T-A transversion in Codon 246 giving rise to a methionine to lysine amino acid substitution. (2) A giant cell glioblastoma disclosed a G to A transition in Codon 285 resulting in a glutamic acid to lysine substitution. Both mutations were associated with loss of the normal allele. Twenty-three DNA fragments that disclosed no mutation by SSCP analysis were confirmed to be negative by direct sequencing of amplified DNA. No mutations were detected in a series of eight juvenile cerebellar astrocytomas, a biologically distinct form of low-grade astrocytoma. Mutations of the p53 gene may play an important pathogenetic role in a subset of human astrocytomas.

Adult↗
PubMed1993

Evaluation of gender differences in urine specific gravity and serum electrolytes in response to varied fluid intake and ibuprofen use.

Heat casualties and other conditions related to suboptimal fluid intake (FI) are common in the military. Current methods to assess FI do not address gender differences or medication use, specifically non-steroidal anti-inflammatory drugs (NSAIDs), which are commonly used in the field. Nine men and six women were prospectively studied while stationed in Saudi Arabia. Urine specific gravity and serum electrolytes were monitored as FI was varied before and after daily ibuprofen (IBP) ingestion. IBP impaired urinary dilution in both men and women, but differences were not statistically significant pre- and post-IBP or between genders. Use of IBP or other NSAIDs may confound usual methods to ensure adequate FI, and soldiers should be specifically questioned about their use before such assessments.

Adult↗
PubMed1989

Acetazolamide and thiamine: an ancillary therapy for chronic mental illness.

Twenty-four chronic schizophrenic patients were treated successfully with the addition of acetazolamide and thiamine (A + T) to their unchanged existing therapies in a double-blind, placebo-controlled crossover study. Therapeutic effects were measured by the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms. Overall, 50% of the patients showed improvement on all assessment scales. No untoward effects occurred in these patients or in patients in previous studies who have been treated continuously with A + T therapy for as long as 3 years.

Acetazolamide↗
PubMed1988

Congenital blindness, porencephaly, and neonatal thrombocytopenia: a report of four cases.

Four unrelated infants with neonatal thrombocytopenia associated with congenital blindness and porencephaly have been seen over an 18-year period. The association of congenital blindness with neonatal thrombocytopenia has not previously been reported. All children had clinical purpura in the neonatal period; in three cases, thrombocytopenia was confirmed, while in one case, the diagnosis of thrombocytopenia was presumptive; in two cases, there was evidence of circulating maternal serum platelet isoantibodies. Extensive investigation for intrauterine infection was negative in the three cases with confirmed thrombocytopenia. The thrombocytopenia resolved spontaneously after the neonatal period. It is postulated that the porencephalies were the consequence of prenatal cerebrovascular episodes. The etiology of the optic atrophy is unclear. Serial cranial ultrasound investigation is recommended for all neonates with thrombocytopenia, even if neurologically asymptomatic in the neonatal period, and serial prenatal cranial ultrasound investigation is recommended for infants of mothers with a history of having previously had infants with neonatal isoimmune thrombocytopenia.

Adolescent↗