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Biomedical subjects

T Brown

Publications and source records attributed to T Brown.

At least 505 records · Page 28Linked to original sources
PubMedDate not supplied

Evaluation of the role of comparison radiographs in the diagnosis of traumatic elbow injuries.

This study attempted to determine whether comparison radiographic views of the uninjured elbow result in increased diagnostic accuracy. Physicians (one junior and one senior orthopaedic resident and an orthopaedic surgeon) were provided with a short clinical summary and asked to interpret radiographs of the injured elbow (IE) or both the injured and uninjured elbow (UE) in a randomized fashion from 25 children with elbow injuries. The overall percentage of correct diagnoses (one vs. two elbow radiographs) were as follows: orthopaedic surgeon, 80 versus 96%; for junior resident, 80 versus 84%; and for senior resident, 84 versus 88% (p > 0.05). Kappa scores for interobserver variability and intrarater agreement were in the high range (0.756 to 0.904, kappa = 0.08). Clinically relevant diagnoses were missed by trainees (not the orthopaedic surgeon) whether radiographs of IE or both IE and UE were interpreted. Incorrect radiograph interpretations were due to false positives in 39 of 40 cases. Comparison radiographs of the UE were not useful in improving diagnostic accuracy in elbow trauma. However, although they may be necessary in some instances, routine radiographic examination of the UE is not warranted.

Adolescent↗
PubMedDate not supplied

Mechanoreception at the cellular level: the detection, interpretation, and diversity of responses to mechanical signals.

Cells from diverse tissues detect mechanical load signals by similar mechanisms but respond differently. The diversity of responses reflects the genotype of the cell and the mechanical demands of the resident tissue. We hypothesize that cells maintain a basal equilibrium stress state that is a function of the number and quality of focal adhesions, the polymerization state of the cytoskeleton, and the amount of extrinsic, applied mechanical deformation. A load stimulus detected by a mechano-electrochemical sensory system, including mechanically sensitive ion channels, integrin-cytoskeleton machinery, and (or) a load-conformation sensitive receptor or nonreceptor tyrosine kinase, may activate G proteins, induce second messengers, and activate an RPTK or JAK/STAT kinase cascade to elicit a response. We propose the terms autobaric to describe a self-loading process, whereby a cell increases its stress state by contracting and applying a mechanical load to itself, and parabaric, whereby a cell applies a load to an adjacent cell by direct contact or through the matrix. We predict that the setpoint for maintaining this basal stress state is affected by continuity of incoming mechanical signals as deformations that activate signalling pathways. A displacement of the cytoskeletal machinery may result in a conformational change in a kinase that results in autophosphorylation and cascade initiation. pp60Src is such a kinase and is part of a mechanosensory protein complex linking integrins with the cytoskeleton. Cyclic mechanical load induces rapid Src phosphorylation. Regulation of the extent of kinase activation in the pathway(s) may be controlled by modulators such as G proteins, kinase phosphorylation and activation, and kinase inhibitors or phosphatases. Intervention at the point of ras-raf interaction may be particularly important as a restriction point.

Biomechanical Phenomena↗
PubMedDate not supplied

Evaluation of virtual reality bronchoscopy as a learning and assessment tool.

BACKGROUND: Conventional training in bronchoscopy involves a trainee performing on a real patient under supervision. This method of training is not only expensive, but there is also potential for increased patient discomfort. Simulators permit the acquisition of necessary technical skills required for the procedure. Virtual reality (VR) has been an integral part of training in aviation, and the application of this technology in medical training needs to be evaluated. OBJECTIVE: This study was conducted to evaluate the efficacy of a VR bronchoscopy simulator as a learning and assessment tool. METHODS: The bronchoscopic simulator (HT Medical Systems, Maryland, USA) is a VR computer programme. The simulator has the ability to assess competence by a set of parameters, which formed the data for the study. Nine novices without previous bronchoscopic experience formed the study group (group 1). Nine experienced bronchoscopists having performed between 200 and 1000 bronchoscopies formed the other group (group 2). We assessed the efficacy of the system as a learning tool by studying whether there was a significant difference between the first and subsequent sessions of the subjects from group 1 and by comparing the performance of the two groups. Statistical analysis was done using the Mann-Whitney U test and the Wilcoxon signed ranks test. RESULTS: There was a significant difference in performance between the first attempt of group 1 and the performance of the experts in terms of percentage of segments visualised and number of wall collisions and the economy of performance. Among the subjects from group 1, there was a significant improvement in percentage of segments visualised by the third attempt (p = 0.04), in the economy of performance by the sixth attempt (0.008) and in the number of wall collisions by the sixth attempt (0.024). When each attempt of the novices was compared with the performance of group 2, the significance in the difference of the percentage of segments studied (p = 0.09) and the economy of performance disappeared by the third attempt (0.06), while the difference in the number of wall collisions disappeared by the fifth attempt (p = 0.06). CONCLUSIONS: This study has been able to establish the face, construct and content validity of the simulator and the potential for it to be an effective training tool.

Bronchoscopy↗
PubMedDate not supplied

Granulomatous disease associated with Bartonella infection in 2 dogs.

Shortly after removal of an engorged tick from the left ear, a 4-year-old Greyhound was referred for evaluation of fever and a rapidly enlarging mass in the region of the left submandibular lymph node. Histopathologic evaluation of the lymph node resulted in a diagnosis of severe granulomatous lymphadenitis. An 11-year-old mixed-breed dog was referred for evaluation of a 6-week history of serous nasal discharge. Histologic examination of a surgical biopsy from a nasal mass indicated multifocal granulomatous inflammation with fibrosis. Serum samples obtained from both dogs were reactive by immunofluorescent assay to Bartonella vinsonii subsp. berkhoffii antigens (reciprocal titers of 128). Although Bartonella organisms were not isolated by lysis centrifugation blood culture, Bartonella DNA was amplified from tissue samples obtained from each dog (lymph node biopsy from dog 1 and nasal biopsy from dog 2) using primers that amplify a portion of the 16S rRNA gene followed by Southern blot hybridization using a genus-specific probe. Additionally, restriction fragment length polymorphism (RFLP) analysis of a Bartonella-specific citrate synthase gene product obtained from dog 2 resulted in a restriction pattern identical to B. vinsonii subsp. berkhoffii. This is the 1st report of granulomatous disease in dogs associated with Bartonella infection.

Amino Acid Sequence↗
PubMedDate not supplied

Confirmed congenital rubella syndrome--A case report.

BACKGROUND: Congenital Rubella Syndrome (CRS) is defined clinically as an illness usually manifesting in infancy, resulting from rubella infection in utero with certain specific signs and symptoms. Confirmed CRS is a clinically consistent case which is laboratory confirmed. A report of a 3 month old male diagnosed with confirmed congenital rubella is here presented on account of its rarity and easy prevention with vaccination. METHOD: The case notes of 3 month old male admitted with features consistent with CRS and managed for overwhelming septicaemia with heart failure and encephalitis and review of literature on the subject using manual library and Medline search. RESULT: The infant's Rubella-specific immunoglobulin M (IgM) antibody demonstrated positive and the rubella antibody level was high at 11.6 IU/ml. CONCLUSION: This is the first report of confirmed CRS in our centre. Though few cases are seen, the effects and defects on the child are severe and irreversible thus, vaccination with Measles-mump-rubella (MMR) vaccine is recommended as part of the National Programme on Immunization and for all females of child bearing age, who did not receive it in childhood.

Eye Abnormalities↗
PubMedDate not supplied

Sheathed in history.

Explore the source record for details and available documents.

Condoms↗
PubMedDate not supplied

Diabetes care: a comparison of management systems.

During 1997, the Alaska Area Diabetes Program audited a sample of 837 charts from among the 1373 individuals receiving regular diabetes care at facilities serving predominantly American Indians/Alaska Natives. Charts were evaluated for the delivery of American Diabetes Association Standards of Care. Results of the audit showed a great deal of variability among facilities. Facilities which scored highly in the audit were more likely to use an organized multidisciplinary team approach that included coordinated clinic appointments with multiple providers on the same day, maintenance of a diabetes registry, proactive preclinic preparation, flow-sheet use, intensive individual nutritional counseling, a case manager or field clinic coordinator system with standing orders, and strong self-management support.

Alaska↗
PubMedDate not supplied

Safety and efficacy of in ovo administration of infectious bursal disease viral vaccines.

In ovo vaccination against Marek's disease virus and infectious bursal disease virus (IBDV) in commercial broilers in the United States is common. Little information exists as to the safety and efficacy of intermediate IBDV vaccines given in ovo. Experiments were initiated to determine the safety and efficacy of three commercially available live intermediate IBDV vaccines by in ovo route. Commonly used vaccines were given at 18 days of embryonation to specific-pathogen-free (SPF) broiler embryos (first and second study) or to commercial broiler embryos (third study) that had maternal antibody against IBDV. When any of the antigenic standard vaccines was given at full dose to SPF embryos, embryonic and 3-wk posthatch mortality increased. Vaccines also caused significant microscopic lesions in the bursa of Fabricius at 1 and 3 wk posthatch. In contrast, there was no adverse effect on embryonic or posthatch mortality when vaccines were given at half dose to SPF or commercial broiler embryos. However, significant microscopic lesions were evident at 1 and 3 wk posthatch in the bursae of SPF embryos given the vaccines at half dose. When vaccines were given at half dose to commercial broiler embryos, lesions were evident at 1 but not 3 wk of age. In the third study, in ovo vaccinated chickens were challenged with either a virulent standard (APHIS) or antigenic variant (variant E) IBDV virus at 3 wk of age. All vaccines produced at least 87% protection against the standard and 60% protection against the variant challenge IBDV, as measured by bursal weight to body weight ratios. This study was the first to examine the safety and efficacy of the three commonly used intermediate IBDV vaccines given in ovo in protection against standard and antigenic variant IBDV challenge viruses.

Animals↗
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Immunohistochemical localization of avian leukosis virus subgroup J in tissues from naturally infected chickens.

The tissue tropism of avian leukosis virus (ALV) subgroup J (ALV-J) was investigated in congenitally infected broiler chickens by an immunohistochemistry technique detecting gp85 viral glycoprotein. All organs examined contained detectable antigen. The most intense staining was in the adrenal gland, heart, kidney, and proventriculus. Intense staining for viral antigen in the heart may explain the ability of ALVs to cause cardiomyopathy. Although recent investigations failed to demonstrate specific viral staining in bone marrow from infected chickens, we were able to show moderate staining in myelocytic precursor cells in bone marrow. This finding agrees with previous work showing cell cultures of bone marrow are susceptible to ALV-J infection and the tendency of subgroup J to predominantly induce myeloid rather than lymphoid neoplasms.

Adrenal Glands↗
PubMedDate not supplied

Distribution of arthritis and osteomyelitis in turkeys with green liver discoloration.

The distribution of arthritis and osteomyelitis (OM) was studied in turkeys with green liver (GL) discoloration collected in a processing plant; the turkeys originated from seven commercial farms. Overall occurrence of GL, arthritis, and OM in the 25,320 inspected toms was 264 (1.04%), 123 (0.49%), and 107 (0.42%), respectively, and in the 16,690 inspected hens was 24 (0.14%), 0%, and 13 (0.08%), respectively. Prevalence of GL, OM, and arthritis varied among the studied farms. Arthritis and/or OM were detected in 168 (58.3%) of 288 turkeys with green discolored livers. Of the 168 turkeys with OM and/or arthritis, 48 (28.6%) had only arthritis, 45 (26.8%) had OM only, and 75 (44.6%) had both lesions. Arthritis and OM were detected in single and multiple sites and were unilateral and bilateral. Distribution of OM in the 120 OM-positive turkeys with and without arthritis was 77 (64.2%) in proximal tibia, 29 (24.2%) in proximal humerus, 28 (23.3%) in proximal femur, 13 (10.8%) in rib cage, and 4 (3.3%) in distal femur. Distribution of arthritis in the 123 arthritis-positive turkeys with and without OM was 77 (62.6%) in shoulder, 45 (36.6%) in stifle, and 25 (20.3%) in hip joints. Findings in this study suggest that arthritis and osteomyelitis are two distinct lesions and that they may develop independently in the same bird.

Animals↗
PubMedDate not supplied

Adenovirus-induced inclusion body hepatitis in four-day-old broiler breeders.

Two separate parent broiler flocks originating from the same grandparent flock experienced mortalities of 23% and 40%, respectively, in chicks between 1 and 14 days of age. Chicks affected at 4 days of age had tremors, depression, and hypoglycemia. They had pale yellow, swollen, friable livers. Pancreata were discolored and hemorrhagic. Spleens were swollen and sightly darkened. Microscopic lesions consisted of multifocal areas of acute hepatic and pancreatic necrosis with numerous basophilic intranuclear inclusions with karyomegaly. Splenic sections had severe lymphoid depletion and reticular cell and macrophage hyperplasia. An adenovirus from affected livers was isolated in chicken embryo liver cells. Serologic evidence suggests that the grandparent flock began egg production seronegative to adenovirus antibodies, was exposed during production, and, subsequently, shed adenovirus vertically to its progeny. The clinical syndrome was reproduced by injecting the isolated adenovirus into 1-day-old antibody-negative chicks. Histologic lesions in the experimentally reproduced disease cases were identical to those in the naturally occurring cases.

Adenoviridae↗