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Biomedical subjects

T Wilson

Publications and source records attributed to T Wilson.

At least 127 records · Page 7Linked to original sources
PubMed1997

The use of signed English pictures to facilitate reading comprehension by deaf students.

Many deaf students have severe difficulty acquiring literacy and developing reading comprehension beyond an elementary school level. This difficulty apparently results from a combination of perceptual, communication, instructional, linguistic, and experiential deficits. Although some deaf students develop a degree of signed English proficiency, this does not necessarily translate into reading proficiency. Recent studies examining the possible association between signed English pictures and comprehension of printed text present some support for facilitation of students' word recognition in a format combining those two elements. Whether this format enhances comprehension remains unclear from previous studies. The present study, involving 16 severely or profoundly deaf students across two reading-proficiency groups, examined whether the use of signed English pictures in association with printed text enhances students' reading comprehension. The study found that comprehension was significantly enhanced by the use of signed English reading books, with poorer readers deriving greater benefit than better readers. Practical implications of the findings are discussed.

Adolescent↗
PubMed1997

The history of urology on postage stamps and cancellations.

PURPOSE: Many important phases and personalities in the history of urology have been depicted on postage stamps, stationery and cancellations. MATERIALS AND METHODS: The article gives a short recounting of several notable events that contributed to the development of urology as chronicled by philatelic material. RESULTS: Beginning with the Egyptian papyri and ending with a recently acknowledged urologist, the historical survey covers uroscopy, lithotomy, lithotrity, anatomy, pathology, instruments, surgical techniques in urology, imaging techniques of the urinary tract, dialysis and renal transplantation. Personalities whose accomplishments have made a deep imprint in the history of urology, if honored on philatelic items, are described in this article. CONCLUSIONS: Although the resulting picture does not necessarily present a continuity, it does emphasize certain peaks and high points in the evolution of this specialty.

History, 15th Century↗
PubMed1996

hMSH2 forms specific mispair-binding complexes with hMSH3 and hMSH6.

The genetic and biochemical properties of three human MutS homologues, hMSH2, hMSH3, and hMSH6, have been examined. The full-length hMSH6 cDNA and genomic locus were isolated and characterized, and it was demonstrated that the hMSH6 gene consisted of 10 exons and mapped to chromosome 2p15-16. The hMSH3 cDNA was in some cases found to contain a 27-bp deletion resulting in a loss of nine amino acids, depending on the individual from which the cDNA was isolated. hMSH2, hMSH3, and hMSH6 all showed similar tissue-specific expression patterns. hMSH2 protein formed a complex with both hMSH3 and hMSH6 proteins, similar to protein complexes demonstrated by studies of the Saccharomyces cerevisiae MSH2, MSH3, and MSH6. hMSH2 was also found to form a homomultimer complex, but neither hMSH3 nor hMSH6 appear to interact with themselves or each other. Analysis of the mismatched nucleotide-binding specificity of the hMSH2-hMSH3 and hMSH2-hMSH6 protein complexes showed that they have overlapping but not identical binding specificity. These results help to explain the distribution of mutations in different mismatch-repair genes seen in hereditary nonpolyposis colon cancer.

Base Sequence↗
PubMed1996

Efficient real-time confocal microscopy with white light sources.

The main advantage of confocal microscopes over their conventional counterparts arises from their ability to optically 'section' nearly transparent materials; the thin image slices thus obtained can be used to reconstruct three-dimensional images, a capability which is particularly useful for the study of biological specimens. Confocal microscopes have previously used either a single laser-illuminated point-source and single point-detector (which are scanned in tandem across the object) or white-light illumination with multiple point-sources and detectors. Single-point-source systems, however, do not usually form images in real time and are restricted to using available laser wavelengths. Multiple-point-source systems, on the other hand, produce images in real time but use light very inefficiently--typically 1% or less is used for imaging. Here we demonstrate a white-light, multiple-point-source method which can in principle produce images in real time with light efficiencies as high as 50%. This system is likely to find broad practical application, particularly in the imaging of weakly reflecting or weakly fluorescent specimens.

Animals↗
PubMed1996

Resveratrol promotes atherosclerosis in hypercholesterolemic rabbits.

The hypothesis was tested that resveratrol, a compound in red wine, would inhibit atherosclerotic development in rabbits fed 0.5% cholesterol for 60 days. Rabbits were supplemented with or without oral resveratrol. During the study, body weights and food consumption were similar for the two groups. The lack of differences between liver weights and a series of serum parameters indicative of liver disease suggest that liver function was similar in the two groups. The diet produced hypercholesterolemia in both groups, but no differences in lipoprotein-cholesterol concentrations. The electrophoretic mobility of plasma low-density lipoprotein (LDL) and plasma LDL after induced oxidation also was not different between the groups. Staining of atherosclerotic lesions in the control and resveratrol-treated groups revealed that the resveratrol-treated rabbits had significantly more aortic surface area covered by atherosclerotic lesions (P < 0.02). Therefore, resveratrol promoted atherosclerotic development, rather than protect against it, by a mechanism that is independent of observed differences in gross animal health, liver function, plasma cholesterol concentrations, or LDL oxidative status.

Animals↗
PubMed1996

Levels of helping: a framework to assist tutors in providing tutorial support at the level students want and need.

Provision of tutorial support for students is an integral part of the nurse tutor's role, Birchenall (1994) going so far as to state 'a teacher must always find time for a student who needs support' (p 1). Given the current changes in nurse education, and the stresses which both tutors and students record, it is worth considering what the boundaries of that support are and what are the most effective ways of delivering it. In reality, there appear to be mixed messages about whether support is solely educational or may also have a pastoral component, and tutors often experience confusion about whether a personal problem is affecting work or vice versa. The current debate about the desirability of clinical supervision (Butterworth & Faugier 1992, Faugier & Butterworth 1994, Kohner 1994) may, while attempting to clarify the situation, succeed in asking teachers to re-examine their role. A framework for helping is offered which might help remove some of that confusion. It is also hoped that this article will reopen the debate about the legitimate role of the personal tutor, and cause managers to consider whether adequate time and attention is given to supporting tutors in this demanding role.

Education, Nursing↗
PubMed1996

The detection of verocytotoxins in bacterial cultures from human diarrhoeal samples with monoclonal antibody-based ELISAs.

Bacterial cultures from 1801 human diarrhoeal faecal specimens were examined for verocytotoxins I and II by monoclonal antibody-based sandwich ELISAs. Of the 68 ELISA-positive cultures selected from initial screening, 32 were positive by ELISA on repeat or from freshly grown cultures. ELISA-positive pure cultures were obtained from 13 of these, of which seven were confirmed as verocytotoxin positive by cytotoxicity assay. These seven strains were typed as O26 (5) and O146 (2). The six false positive results were from isolates of Enterobacter sp. (1), Citrobacter Freundii (1) and Escherichia coli (4), one each of types O1, O18ac and O98 and an untypable strain. Despite the occurrence of false positive reactions, sandwich ELISA was a useful method for the rapid screening of samples, and detected verocytotoxin-positive E. coli strains, other than O157, from patients with clinical conditions in which they could be implicated.

Adult↗
PubMed1996

Ethanol-induced alterations in the posttranslational processing, but not secretion of luteinizing hormone-releasing hormone in vitro.

The effects of ethanol (EtOH) on the male hypothalamic pituitary reproductive axis are multiple and varied. Although direct gonadal toxicity has been reported, hypothalamic-pituitary perturbations have also been noted. The difficulty of sampling the hypothalamus has made direct investigation of EtOH-induced alterations on luteinizing hormone-releasing hormone (LHRH) fraught with interpretation problems. To circumvent this, we have conducted a series of experiments exploring the effect of 200 mg% EtOH in vitro on GT1-7 cells, a newly developed LHRH secreting neural cell line. Cell lines were treated with EtOH-containing or EtOH-free media for 2, 6, 24, or 48 hr. EtOH caused no significant change in LHRH secretion at any time point, although there was a trend to increased secretion after 2 hr EtOH exposure when compared with control. Significantly increased total (i.e., cellular plus secreted) pro-LHRH coupled with significantly reduced cellular LHRH after 6 hr only of EtOH exposure suggested that EtOH caused a transient decrease in processing from bioinactive pro-LHRH to bioactive LHRH. However, even at this time point, LHRH secretion from these EtOH-exposed cells was no different than from control cells. Steady-state LHRH mRNA levels were not changed by EtOH at any time point. These findings are concordant with previous in vitro data using hypothalamic tissue that has similarly demonstrated no effect of EtOH on LHRH secretion. Taken together with the in vivo demonstration that EtOH reduces hypothalamic-pituitary portal blood levels of LHRH, these data indicate that EtOH exerts its effect either at an extrahypothalamic locus and/or on non-LHRH-producing cells within the hypothalamus.

Animals↗
PubMed1995

A bacterial luciferase reaction with a negative temperature coefficient attributable to protein-protein interaction.

A yellow fluorescent protein (YFP) present in a strain of bioluminescent bacteria is shown here not only to modify the color and intensity of the emission, as already known and attributed to the interaction of YFP with a luciferase intermediate, but also remarkably to confer a negative temperature dependence to the in vitro system. The in vitro bioluminescence decay rate is actually independent of temperature in the range 5-25 degrees C, at approximately 1 microM YFP concentration. Several hypotheses are considered to explain this effect, based either on inactivation of YFP itself at higher temperatures or on its binding equilibrium with the luciferase intermediate. The first hypothesis is favored. Fluorescence anisotropy measurements show that YFP loses its chromophore at higher temperatures, but this alone cannot account for the negative temperature dependence. Gel chromatography shows the existence of an inactive YFP dimer, and the formation of more dimer at higher temperatures cannot be ruled out but is unlikely in our experimental conditions. Conformational changes may contribute to YFP inactivation. To our knowledge, there is no prior example of an enzymatic reaction in which the rate is slower at higher temperatures, within a physiological range.

Anisotropy↗
PubMed1995

Laparoscopic cholecystectomy: its impact on national health economics.

OBJECTIVE: To assess whether sound economic reasons exist for the wider introduction of laparoscopic cholecystectomy in Australia. DESIGN: A retrospective survey of patients who underwent laparoscopic cholecystectomy. We compared time of hospital stay and time off work after laparoscopic cholecystectomy with data for open cholecystectomy. PATIENTS AND SETTING: Seventeen participating surgeons in four Australian States allowed access to patients treated between May 1990 and November 1991 (1254 patients in all). MAIN OUTCOME MEASURES: Patient acceptability of the procedure, average length of postoperative in-hospital stay, and the savings associated with earlier return to work compared with open cholecystectomy. RESULTS: Almost 90% of patients (1127) replied and 1088 responses were considered appropriate for analysis. Serious complications were rare; 96% of patients thought the technique was successful. The mean length of in-hospital stay was 2.6 days (range, 1-120), compared with a mean of 8.7 days for open cholecystectomy. Among working patients, the mean time to return to work was 11.6 days (range, 10.7-13.1), an estimated 27 days sooner than after open cholecystectomy. Extrapolating from these results, replacing 95% of open cholecystectomies with laparoscopic procedures would have 133,285 hospital bed-days and 500,000 work-days each year. CONCLUSION: Laparoscopic cholecystectomy is safe and effective. Its wider use in Australia would result in savings to both the individual and the national economy.

Absenteeism↗
PubMed1995

Magnetic resonance imaging and mood disorders. Localization of white matter and other subcortical abnormalities.

BACKGROUND: Recent reports in the literature document an association between focal white matter abnormalities in bipolar as well as unipolar mood disorder. The importance of this finding and other associated anatomic differences is uncertain. METHODS: We examined the volume of abnormal white matter and other brain volumes using quantitative magnetic resonance imaging analysis. We explored the relationship of these variables with diagnosis, cognitive function, and clinical variables in 36 patients with bipolar disorder, 30 patients with unipolar disorder, and 26 control subjects who were free from significant medical and neurologic illness. RESULTS: Younger patients with bipolar disorder (but not similarly aged patients with unipolar disorder or controls) have an increased volume of abnormal white matter. Data also indicate that the total volume of abnormal white matter may be associated with increased cognitive impairment, increased rate of psychiatric illness in the family, and onset after adolescence. CONCLUSION: Patients with bipolar disorder demonstrate a pattern of subcortical brain morphologic abnormalities and cognitive impairment.

Adult↗
PubMed1995

Reactive oxygen species as cellular messengers.

Reactive oxygen species (ROSs) have recently been found to be important signaling molecules in several cellular responses. Individual species have characteristic reactive properties, yet are easily interconverted, making it difficult to identify the ROSs involved in each response.

Animals↗
PubMed1995

Fusarium proliferatum-fermented corn stimulates development of placental glutathione S-transferase-positive altered hepatic foci in female rats.

Groups of 8 6-w-old female Sprague-Dawley rats were initiated with 30 mg diethylnitrosamine (DEN)/kg. Control and initiated groups were fed a semipurified diet or diets supplemented with Fusarium proliferatum-contaminated corn to contain 20 or 50 mg fumonisin B1 (FB1)/kg. Histochemical staining for gamma-glutamyltransferase (GGT) and immunochemical staining for placental glutathione S-transferase (PGST), markers of altered hepatic foci (AHF), were performed on serial frozen hepatic sections. Gamma-glutamyltransferase -(+) AHF were not found in any group. Dosing with DEN significantly increased the number of PGST-(+) hepatocytes compared to the uninitiated groups. Groups fed F proliferatum-containing diets also had a significantly increased number of PGST-(+) AHF compared with those fed no F proliferatum. The volume percentage of liver occupied by PGST-(+) foci was significantly greater in the groups treated with DEN or F proliferatum. The number of PGST-(+) AHF/liver in the groups given DEN was also significantly greater than in the uninitiated groups. Fusarium proliferatum exposure also significantly increased the number of PGST-(+) AHF/liver. Feeding F proliferatum containing 20 mg FB1/kg promoted the development of DEN-initiated AHF in rats. Placental glutathione S-transferase was a more useful marker than GGT in detecting AHF produced by small amounts of F proliferatum mycotoxins fed after initiating dosing with DEN.

Animals↗
PubMed1994

inhA, a gene encoding a target for isoniazid and ethionamide in Mycobacterium tuberculosis.

Isoniazid (isonicotinic acid hydrazide, INH) is one of the most widely used antituberculosis drugs, yet its precise target of action on Mycobacterium tuberculosis is unknown. A missense mutation within the mycobacterial inhA gene was shown to confer resistance to both INH and ethionamide (ETH) in M. smegmatis and in M. bovis. The wild-type inhA gene also conferred INH and ETH resistance when transferred on a multicopy plasmid vector to M. smegmatis and M. bovis BCG. The InhA protein shows significant sequence conservation with the Escherichia coli enzyme EnvM, and cell-free assays indicate that it may be involved in mycolic acid biosynthesis. These results suggest that InhA is likely a primary target of action for INH and ETH.

Amino Acid Sequence↗
PubMed1994

Prenatal sonographic detection of intra-abdominal extralobar pulmonary sequestration: report of three cases and literature review.

Three cases of intra-abdominal extralobar pulmonary sequestration detected antenatally by ultrasound are reported. One case was associated with a large left diaphragmatic hernia. Sonographically, all the cases were found in the left supra-renal region presenting as a well-defined echogenic mass with cystic hypoechoic areas. The condition should be considered in the differential diagnosis of all antenatally detected upper abdominal echogenic masses, particularly when associated with a diaphragmatic hernia. Postnatal ultrasound-guided fine needle aspiration biopsy in one case yielded respiratory type epithelium and this procedure could provide a reasonably confident diagnosis of the lesion.

Abdomen↗
PubMed1994

Dynamic variations in the expression of type I collagen and its molecular chaperone Hsp47 in cells of the mouse dental follicle during tooth eruption.

Tooth eruption is a precisely timed and sequenced event that brings the tooth from within bone into a functional position in the mouth. Every part of the developing tooth has been theoretically implicated as a primary factor in this process, but it now appears that eruption is multifactorial, with the dental follicle and type I collagen playing an important part. Immunological probes were used here to investigate in vivo and in vitro the temporal and spatial expression of type I collagen and its molecular chaperone Hsp47 in the dental follicle during eruption. Mandibles were dissected from 2-, 5-, 9- and 11-day-old neonatal mice and fixed in 95% ethanol overnight. Sections of 7 microns were obtained and reacted with antibodies directed against type I collagen. Dental follicles were isolated from 2-, 5-, 9- and 11-day-old neonates and cells were grown in culture for 8 days. Slides were then reacted with antibodies directed against type I collagen and Hsp47. The production of type I collagen and Hsp47 in the follicle varied with the stage of dental development and eruption. There was a progressive decrease of type I collagen in the coronal part of the follicle, leading to an arrest of its production in these areas. These findings support the notion that cells of the coronal portion of the dental follicle stop producing type I collagen as a prerequisite to the initiation of tooth eruption and that this phenotype persists in vitro.

Animals↗