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Biomedical subjects

T W Smith

Publications and source records attributed to T W Smith.

At least 19 recordsLinked to original sources
PubMed2002

Market age live weight, carcass yield, and liver characteristics of broiler offspring from breeder hens fed diets differing in fat and energy contents.

The effects of energy level, fat type, and fat level in breeder hen diets on subsequent offspring market age live BW, carcass yield, and liver characteristics from breeder hens at 29 and 36 wk of age were evaluated. At 22 wk of age, six dietary treatments were imposed. Dietary treatments contained: 1) 3.0%, added poultry fat (PF) and 467 (high energy) kcal/hen per day at peak production (CPP), 2) no added fat and high energy, 3) 3.0% added PF and 430 (low energy) CPP, 4) no added fat and low energy, 5) 1.5% added PF and 449 (moderate energy) CPP, and 6) 3.0% added corn oil (CO) and moderate energy. Breeder age influenced Day 43 broiler live BW, percentage total carcass and front-half yields, and liver moisture contents. Furthermore, wet and dry liver weights were higher in female broilers compared to those of male broilers from 29-wk-old breeder hens. Live BW was higher in broilers from hens fed low-energy diets compared with moderate-energy diets and 3.0% compared to 1.5% PF diets. Percentage liver DM was higher in females compared to male broilers from hens fed 3.0% CO and moderate energy and was highest in male and female broilers from hens fed 1.5% PF and moderate energy. Percentage wet liver weight and liver DM were higher and liver moisture content was lower in broilers from hens fed 1.5% compared to 3.0% PF diets. Overall, energy and fat levels in breeder diets had subsequent influences on market age weight and liver characteristics of broilers.

Abattoirs↗
PubMed2001

Inter-laboratory comparison of DNA preservation in archival paraffin-embedded human brain tissue from participating centres on four continents.

DNA extracted from formalin-fixed and paraffin-embedded brain tissue is known to contain as yet ill-characterized inhibitors of the PCR process. As part of a project that aims to clarify the role of mitochondrial DNA sequence variation in human neurodegenerative diseases using DNA from various ethnic backgrounds, we have investigated factors that influence the preservation of archival DNA and its suitability for PCR. In this study, neuropathological tissue samples were analysed that had been routinely processed in 18 international centres on four continents. Following DNA extraction, PCR amplification of mitochondrial and nuclear DNA sequences was performed with and without additional purification of the template DNA. In addition, the DNA used for PCR was analysed by HPLC. Phosphate-buffered formalin proved to be a superior fixative compared with unbuffered aldehyde: DNA extraction resulted in greater yields, the molecular weight of the isolated DNA was higher and PCR was more successful. PCR inhibitors were identified as (1) high concentrations of small (<300 bp) DNA fragments that competitively compete with template DNA and (2) contaminants of the DNA template solution including denatured protein that cannot be completely removed by phenolic extraction. HPLC analysis did not reveal significant qualitative differences between DNA isolated from fresh-frozen tissue samples and DNA recovered from formalin-fixed, paraffin-embedded brain tissue. The fact that DNA could be amplified from the majority of tissue specimens in this study suggests that rare diseases and diseases where ethnic background plays an important role can be sampled for genetic polymorphism analysis on a global scale using archival neuropathological collections.

Alzheimer Disease↗
PubMed2001

Subacute diencephalic angioencephalopathy: biopsy diagnosis and radiological features of a rare entity.

Subacute diencephalic angioencephalopathy (SDAE) is a rare and fatal disease of unknown etiology that involves the thalami bilaterally. To date, there have been four cases reported, in which the diagnosis was established only after post mortem examination of the brain. We report two male patients, ages 69 and 41 years, who presented with progressive dementia and somnolence. Radiological evaluation revealed enhancing lesions involving both thalami. The differential diagnosis included a number of neoplastic, inflammatory and vascular processes. In both cases, pathological evaluation of biopsy specimens suggested the diagnosis of SDAE. Despite supportive care, the disease progressed rapidly and both patients died within weeks after initial presentation. The diagnosis was confirmed at autopsy in both cases. SDAE is a rare cause of bithalamic disease that can be mistaken for a neoplasm as well as a number of conditions that necessitate different treatment choices. The histopathological findings can establish the diagnosis when combined with radiological and clinical information. This report emphasizes the utility of stereotactic biopsy in early diagnosis of SDAE.

Adult↗
PubMed2001

Functional evaluation of the modified Elmslie-Trillat procedure for patello-femoral dysfunction.

A series of 28 knees in 27 patients were evaluated at an average of 36 months following surgical treatment for patella dislocation, patello-femoral pain, or a combination of both. All cases were treated by the modified Elmslie-Trillat procedure, which involves a lateral retinacular release and medialisation of the tibial tubercle on a distal pedicle. The evaluation included subjective, objective (Fulkerson and Kujala functional knee scores) and radiographic assessments. Subjectively, eight knees (28%) had excellent results, nine knees (33%) good results and seven knees (25%) fair results, accounting for an overall improvement of 86% over the preoperative status. All the knees in patients with a primary symptom of patella dislocation had an excellent or good subjective result, whilst only four knees (40%) in those patients with a primary symptom of pain and four knees (44%) in those with both pain and dislocation had a good or excellent result. The mean objective knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. There have been no further episodes of dislocation in all patients. Six knees (21%) required later screw removal. The modified Elmslie-Trillat procedure produces a favourable outcome in patients with patella dislocation.

Adolescent↗
PubMed2001

Breeder age influences embryogenesis in broiler hatching eggs.

The effects of dietary fat and broiler breeder age on egg and embryo characteristics during incubation were investigated. Breeders were fed diets containing no added fat or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen day (pC/d), or 1.5% PF or 3.0% corn oil at 449 pC/d. Feeding of diets was initiated at 22 wk, and eggs were collected for incubation at 27 and 36 wk of age. Percentage incubational egg weight loss was determined between day of set and Days 6, 12, and 18. Percentage wet and dry embryo weights, embryo moisture content, and eggshell weights were determined at 6, 12, and 18 d of incubation. Percentage yolk sac weight and wet and dry liver weights and moisture content were determined on Days 12 and 18. Percentage gall bladder weight was determined on Day 18. There were no observed effects due to breeder diet. However, eggshell weight at Days 6, 12, and 18 was higher in 27-wk-old hens compared with 36-wk-old hens. Conversely, egg weight loss between Day 0 and Days 6, 12, and 18 and yolk sac weight across Days 12 and 18 of incubation were lower in eggs at 27 wk of age compared with 36 wk. At Day 18, dry embryo weight was higher and wet liver weight was lower at 27 wk compared with 36 wk. A slower rate of DM accumulation in embryos at Week 36 compared to Week 27 was associated with increased incubational water loss and decreased embryo moisture content, eggshell percentage, and yolk sac absorption rate. These data demonstrate that changes in eggshell characteristics with broiler breeder age can alone impact yolk uptake, growth, and body composition in subsequent embryos.

Age Factors↗
PubMed2001

Expression of the p20 gene from Bacillus thuringiensis H-14 increases Cry11A toxin production and enhances mosquito-larvicidal activity in recombinant gram-negative bacteria.

Experimental analyses with recombinant Escherichia coli and Pseudomonas putida transformed with plasmids bearing genes coding for the Cry11A toxin and P20 protein from Bacillus thuringiensis H-14 showed that cells producing both proteins were more toxic when fed to third-instar Aedes aegypti larvae than were cells expressing cry11A alone; the 50% lethal concentrations were in the range of 10(4) to 10(5) cells/ml. Western blots revealed a higher production of Cry11A when the p20 gene was coexpressed. Cry11A was detected primarily in insoluble form in recombinant cells. Cry11A was not detected in P. putida when P20 was not coproduced, and these recombinants were not toxic to larvae, whereas P. putida recombinants producing both proteins were toxic at concentrations similar to those for E. coli. A coelution experiment was conducted, in which a p20 gene construct producing the P20 protein with an extension of six histidines on the C terminus was mixed with the Cry11A protein. The results showed that Cry11A bound to the P20(His(6)) on a nickel chelating column, whereas Cry11A produced without the P20(His(6)) protein was washed through the column, thus indicating that Cry11A and P20 physically interact. Thus, P20 protein either stabilizes Cry11A or helps it attain the folding important for its toxic activity.

Aedes↗
PubMed2001

Disruption of Ini1 leads to peri-implantation lethality and tumorigenesis in mice.

SNF5/INI1 is a component of the ATP-dependent chromatin remodeling enzyme family SWI/SNF. Germ line mutations of INI1 have been identified in children with brain and renal rhabdoid tumors, indicating that INI1 is a tumor suppressor. Here we report that disruption of Ini1 expression in mice results in early embryonic lethality. Ini1-null embryos die between 3.5 and 5.5 days postcoitum, and Ini1-null blastocysts fail to hatch, form the trophectoderm, or expand the inner cell mass when cultured in vitro. Furthermore, we report that approximately 15% of Ini1-heterozygous mice present with tumors, mostly undifferentiated or poorly differentiated sarcomas. Tumor formation is associated with a loss of heterozygocity at the Ini1 locus, characterizing Ini1 as a tumor suppressor in mice. Thus, Ini1 is essential for embryo viability and for repression of oncogenesis in the adult organism.

Animals↗
PubMed2001

Absence of hippocampal sclerosis in children with multiple daily seizures since infancy.

We report a series of nine children with multiple daily seizures since infancy who underwent functional hemispherectomy that included en bloc resection of the hippocampus and the temporal neocortex. In all cases, the hippocampi were normal by conventional histology despite the fact that these patients had suffered from recurrent seizures over a long period of time. This observation suggests that extremely frequent seizures in childhood are not invariably associated with the development of hippocampal sclerosis.

Child↗
PubMed2001

Distinguishing narcissism and hostility: similarities and differences in interpersonal circumplex and five-factor correlates.

Narcissism and hostility are both characterized by dysfunctional social interactions, including tendencies to perceive slights, experience anger, and behave aggressively. The aim of this study was to examine the similarities and differences of narcissism and hostility, using 2 conceptual tools-the interpersonal circumplex and the Five-factor model. In a sample of 292 undergraduate men and women, composite measures of hostility (i.e., Buss-Perry Aggression Questionnaire [Buss & Perry, 1992] and Cook-Medley Hostility [Cook & Medley, 1954] total scores) were inversely correlated with affiliation and unrelated to dominance. In contrast, composite narcissism scores (i.e., Narcissistic Personality Inventory) were positively correlated with dominance and inversely correlated with affiliation. Examination of components of these traits revealed additional similarities and differences, as did associations with other dimensions of the Five-factor model. These findings suggest that the traits of narcissism and hostility are distinguishable by their interpersonal referents, as are their components.

Adult↗
PubMed2000

Positive CSF HSV PCR in patients with GBM: a note of caution.

Because two patients with temporal lobe glioblastomas had herpes simplex (HSV) DNA detected in CSF using PCR at the time of their presentation, we reviewed our laboratory's experience and performed PCR on a bank of 159 frozen CSF samples from patients with glioblastoma multiforme and other neurologic disorders. Based on the inability to detect HSV in any other tumor sample, we conclude that the positive HSV PCR in our two index patients most likely represented false-positive results. A diagnosis of HSE should not be made by PCR alone when the clinical presentation is atypical.

Brain Neoplasms↗
PubMed2000

Vigilance, active coping, and cardiovascular reactivity during social interaction in young men.

This study of 72 undergraduate men examined the effects of two determinants of cardiovascular response-active coping and vigilance-on blood pressure and heart rate responses to social stressors. Observation of a future debate partner (i.e., vigilance) evoked larger increases in blood pressure than did observation of a less relevant person, apparently through the combination of increases in cardiac output and vascular resistance. Preparation and enactment of efforts to exert social influence (i.e., active coping) evoked heightened blood pressure and heart rate responses through increased cardiac contractility and output. Thus, both vigilance and active coping in social contexts increased cardiovascular reactivity, but apparently through different psychophysiological processes.

Adaptation, Psychological↗