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Biomedical subjects

G Clarke

Publications and source records attributed to G Clarke.

At least 55 records · Page 3Linked to original sources
PubMed1998

Rectal washout eliminates exfoliated malignant cells.

PURPOSE: Irrigation of the rectal stump before anastomosis after resection for carcinoma is accepted colorectal surgical practice. However, not all surgeons perform this routinely, and it has never been established conclusively that irrigation of the rectal stump eliminates exfoliated malignant cells or even reduces local recurrence. The patients of a surgeon whose standard surgical practice involved rectal irrigation were compared with those of a surgeon who does not routinely practice rectal irrigation. METHOD: Ten patients were given rectal washout with 200 to 500 ml of normal saline introduced via a Foley catheter per rectum. Ten patients were not given rectal washout. In both groups the anastomosis was performed with a circular stapler, and the stapler and donuts were rinsed in 200 ml of normal saline. The saline was sent for cytologic examination and classified as malignant cells seen or no malignant cells seen. The cytopathologist was blinded to the washout status. RESULTS: Of the ten patients who had rectal washout performed, none had malignant cells seen. Of the ten patients who did not have rectal washout performed, eight had malignant cells seen in the cytology (P = 0.007; two-tailed Fisher's exact probability test). CONCLUSION: Rectal washout eliminates exfoliated malignant cells in the rectum in the vicinity of the anastomosis.

Aged↗
PubMed1998

A comparison of the laryngeal mask airway and cuffed oropharyngeal airway in anesthetized adult patients.

UNLABELLED: We compared the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) in 120 anesthetized adult patients. We compared 1) placement success rates, 2) airway interventional requirements, 3) airway stability in different head/neck positions, 4) cardiorespiratory tolerance, and 5) intra- and postoperative adverse events/symptoms. A standardized anesthesia protocol was followed by four anesthesiologists experienced with both devices. Observational data were validated by independent analysis of continuous video recordings. Postoperative interviews were double-blind to the device used. The LMA had a more frequent success rate than COPA (97% vs 55%, P < 0.00001), an overall higher success rate (100% vs 83%; P = 0.001), a shorter time to achieve an effective airway (49 vs 188 s; P < 0.00001), a higher oropharyngeal leak pressure (21 vs 16 cm H2O; P = 0.003), and a fewer number of chin lift airway interventions required (0.1% vs 42%; P < 0.00001). When comparing mean tidal volumes in different head/neck positions to assess airway stability, the quality of airway was unchanged in 98% patients with the LMA and 54% with the COPA (P < 0.00001). The incidences of intraoperative adverse events were similar. On removal, blood was detected more often on the COPA (3% vs 14%; P = 0.04). In the late postoperative period, more patients complained of adverse symptoms with the COPA than with the LMA (26% vs 57%; P = 0.001). Late postoperative symptoms occurred more frequently with the COPA (0.87 vs 0.34; P = 0.003). There was more late postoperative sore throat (14% vs 36%; P = 0.0003) and more jaw/neck pain (12% vs 26%; P = 0.0008) in patients managed with the COPA. This study demonstrates that the LMA offers advantages over the COPA in most technical aspects of airway management and in terms of postoperative morbidity. IMPLICATIONS: In this randomized, prospective study, we compared the laryngeal mask airway and the cuffed oropharyngeal airway in anesthetized patients. The laryngeal mask airway offers advantages in most technical aspects of airway management and in terms of postoperative morbidity.

Adult↗
PubMed1997

The role of alpha-2 adrenoceptors in the regulation of oxytocin neurones in the suckled rat.

The role of alpha-2 adrenoceptors in the milk-ejection reflex was investigated by making electrophysiological recordings from oxytocin neurones in the supraoptic nucleus of urethane-anaesthetised rats. Systemic administration of the alpha-2 adrenoceptor antagonist. Idazoxan (0.5 mg/kg, i.v.), temporarily suppressed OT cell bursting activity, while having no consistent action on basal neuronal activity. Clonidine (25 micrograms/kg, i.v.) caused an immediate increase in the frequency and amplitude of oxytocin cell bursting, coincident with a fall in basal activity. A higher dose of clonidine (50 micrograms/kg, i.v.), inhibited both bursting and basal activity. These results indicate that alpha-2 adrenoceptors are essential for the normal functioning of the milk-ejection reflex and may be involved in the facilitatory and inhibitory regulation of suckling-evoked bursting in oxytocin neurones.

Adrenergic alpha-Agonists↗
PubMed1997

Interferon-associated thyroid dysfunction in anti-D-related chronic hepatitis C.

To assess the frequency and nature of thyroid abnormality in association with interferon (IFN) therapy alone and in combination with ribavirin, 19 patients receiving IFN therapy for hepatitis C virus (HCV)-induced liver disease had thyroid function tests assessed on a monthly basis. Group I (n = 9) patients received 5 million U of IFN s.c. daily for 2 weeks, followed by 3 million U three times per week for 6 months. Group II (n = 10) patients received 3 million U IFN s.c. three times per week together with ribavirin 400 mg twice daily orally for 6 months. Five of 19 patients (26.3%) developed thyroid abnormalities, 3 (33.3%) in group I and 2 (20%) in group II. Three patients developed thyroid function tests consistent with hyperactivity, and 2 of these normalized on cessation of IFN therapy. One patient continued on IFN but remained clinically euthyroid with antithyroid treatment. Two patients developed thyroiditis and required thyroid supplementation. (One of the 2 had pretreatment antimicrosomal thyroid antibodies and a positive family history of thyroid disease.) Of the 3 patients with HCV type 1b, 1 had pretreatment thyroid antibodies, and all 3 had antibodies during IFN therapy. Neither of the 2 patients with genotype 3 had pre-IFN or post-IFN thyroid antibodies. Patients on IFN therapy need regular thyroid function testing. The frequency of abnormal thyroid tests may be dose related. HCV genotype may influence the development of thyroid antibodies.

Antiviral Agents↗
PubMed1997

Delivery of normal twins following the intracytoplasmic injection of spermatozoa from a patient with 47,XXY Klinefelter's syndrome.

Klinefelter's syndrome is a disorder of gonadal development and typically reveals a 47,XXY karyotype although mosaic forms also occur. Azoospermia is a common feature, but severe oligozoospermia and fertility have been reported. In this study, we have used intracytoplasmic sperm injection (ICSI) to achieve a live twin birth using spermatozoa from a 47,XXY man who has occasional spermatozoa present in the ejaculate. Spermatozoa were obtained from multiple ejaculates and frozen prior to commencing IVF treatment. Nine good quality embryos developed from the injection of 13 oocytes. All nine embryos were frozen. The initial transfer of two frozen-thawed embryos was unsuccessful. In the following cycle, the transfer of two additional frozen-thawed embryos resulted in the delivery of normal, healthy male and female twins. Five embryos remain frozen. It has generally been thought that the germ cells of 47,XXY men are unable to proceed through meiosis. Any spermatozoa produced have been assumed to come from a normal germ cell and therefore likely to have a normal karyotype. However, recent evidence suggests that meiosis of 47,XXY germ cells may be possible. Whether spermatozoa in these men arise from meiosis of 47,XXY germ cells, or from germ cells which have attained a normal karyotype by loss of an X chromosome, is unclear. Any risks in using spermatozoa from these patients have not yet been established. Patients need to be advised accordingly, and preimplantation or prenatal diagnosis should be considered. A cautious approach to the treatment of these patients is therefore warranted.

Adult↗
PubMed1997

Primary hepatic lymphoma in a man with chronic hepatitis C.

We report the case of a middle-aged man who presented de novo with abdominal pain and hepatomegaly and was found to have positive serology for hepatitis C and subsequently a primary hepatic lymphoma. An increased incidence of primary hepatocellular cancer is well characterized in both cirrhotic and non-cirrhotic cases of chronic hepatitis C. The relationship between chronic hepatitis C and primary hepatic lymphoma remains obscure. It has been established that hepatitis C can sustain the clonal B-cell expansion that occurs in associated cryoglobulinaemia, and hepatitis C RNA has been detected within extrahepatic lymphoma tissue. Viral aetiologies for lymphoma are well characterized, such as Epstein-Barr virus (EBV) and human T-cell leukaemia virus (HTLV) I and II. Existing models of chronic infection causing lymphoma within the gastrointestinal tract include that of Helicobacter pylori and mucosa-associated lymphoid tumour of the stomach. Given the relatively low frequency of occurrence it may be prudent to perform a retrospective analysis on past cases of primary hepatic lymphoma in order to determine whether or not hepatitis C was present.

Antibodies, Neoplasm↗
PubMed1997

Manual development for the treatment of child and adolescent disorders.

There has been a proliferation of treatment manuals in the past decade as part of an effort to operationalize treatment applications and standardize treatments across subjects, settings, and therapists. In this article we present the essential elements needed to develop manuals for the psychosocial and psychopharmacological treatments of child and adolescent disorders, using one modality or in multimodal treatment trials. We delineate how to integrate various treatment components for psychosocial and psychopharmacological manuals, as well as those for control conditions. We also examine the therapist variable as it concerns training and adherence to the structured or flexible scripted manuals. Finally, we discuss the advantages and disadvantages of manuals in terms of how they may affect outcome, recommending that treatments be both empirically grounded and clinically meaningful.

Adolescent↗
PubMed1996

TNF alpha mimics the endocrine but not the thermoregulatory responses of bacterial lipopolysaccharide (LPS): correlation with FOS-expression in the brain.

Thermoregulatory and plasma corticosterone responses to peripheral LPS and TNF alpha were compared and correlated with brain FOS protein expression. TNF alpha mimicked the corticosterone response evoked by LPS and the increase in FOS expression in the hypothalamic PVN. TNF alpha also mimicked LPS-activation of central noradrenergic and adrenergic neurones. TNF alpha did not induce a hypothermia which might reflect its failure to activate the vasopressin neurones of the BNST.

Animals↗
PubMed1995

High-resolution renal SPECT in eight minutes using a multi-detector gamma camera.

Planar renal scintigraphy with Tc-99m DMSA has become established as a standard diagnostic test to determine if a kidney has been scarred by infection. It has been suggested that high resolution SPECT may improve the sensitivity of detection of renal scars. To determine if it is possible to produce good quality renal SPECT with a short acquisition time, 10 adults were examined with a new multi-detector gamma camera using 8 minute, 16 minute, and 32 minute acquisitions. The number of defects seen (N = 16) with an 8 minute acquisition was not significantly different from the defects (N = 15) seen using a 16 minute and a 32 minute acquisition. In adults when imaging with a multi-detector gamma camera there was no clinical advantage in using an acquisition of longer than 8 minutes.

Adolescent↗
PubMed1995

Bacterial lipopolysaccharide-induced changes in FOS protein expression in the rat brain: correlation with thermoregulatory changes and plasma corticosterone.

In the present study the regions of the brain showing an increase in the number of FOS protein stained cells 180 min following intravenous saline or bacterial lipopolysaccharide (LPS) treatment were investigated and correlated with changes in body temperature and plasma corticosterone levels. Particular attention was given to the possible involvement of the circumventricular organs and regions of the brainstem containing central noradrenergic neurones. LPS at doses of 0.35, 3.5 and 50 micrograms caused highly significant increases in FOS protein expression in the organum vasculosum of lamina terminalis, the area postrema and the subfornical organ compared with saline controls. Marked increases in bacterial lipopolysaccharide-induced FOS protein expression were observed in the ventrolateral medulla, the nucleus of the solitary tract and the locus coeruleus which contain the A1, A2 and A6 noradrenergic neurones respectively. The changes in body temperature induced by LPS were found to be dependent upon the dose of LPS administered; the lowest dose employed (0.35 micrograms) induced an immediate and sustained fever, 3.5 micrograms LPS caused a biphasic response consisting of a hypothermic response followed by a febrile response, whereas 50 micrograms LPS induced a hypothermic response which then normalised by 160 min post-injection. Intravenous saline injection had no significant effect on body temperature. The occurance of LPS-induced hypothermia was coincident with increased FOS expression in the bed nucleus of stria terminalis, which houses vasopressinergic neurones involved in antipyresis, whereas in animals showing an LPS-induced febrile response there was no significant difference in the number of FOS stained cells in the bed nucleus of stria terminalis compared with saline treated animals. LPS also caused marked increases in FOS protein expression in the parvocellular regions of the paraventricular nucleus (pPVN) of the hypothalamus, the central nucleus of the amygdala and the ventral septal area. Plasma corticosterone was unaffected by the lowest dose of LPS (0.35 micrograms), however the higher doses employed (3.5 and 50 micrograms) caused significant increases in plasma corticosterone which correlated with the increases in the number of FOS stained cells in the pPVN. The results of the present study suggest that, in addition to the organum vasculosum of lamina terminalis, the area postrema and subfornical organ may be important in the responses to antigenic challenge that are mediated by the central nervous system. They also add support to the possible involvement of the bed nucleus of stria terminalis in LPS-induced hypothermia and of the involvement of the of the major noradrenergic cell groups (A1, A2 & A6) and a number of hypothalamic and extrahypothalamic forebrain regions in the interaction of immune and central nervous systems.

Animals↗
PubMed1995

Expression of the mitochondrial uncoupling protein gene from the aP2 gene promoter prevents genetic obesity.

The brown fat-specific mitochondrial uncoupling protein (UCP) provides a mechanism for generating heat by uncoupling respiration and oxidative phosphorylation. It has been suggested that this system of thermogenesis can provide a defense against obesity. To test this idea, we created a transgenic mouse in which the fat-specific aP2 gene promoter directed Ucp expression in white fat and provided for the constitutive expression of Ucp in brown fat. Transgenic mice showed both Ucp mRNA and immunoreactive UCP in white fat at 2-10% the level normally measured in brown fat. A reduction in subcutaneous fat of aP2-Ucp C57BL/6J mice was observed at 3 mo of age. When the transgene was expressed in Avy genetically obese mice reductions in total body weight and subcutaneous fat stores were observed. Female transgenic Avy mice at 13 mo of age weighed 35 grams, a weight indistinguishable from nontransgenic C57BL/6J mice. Gonadal fat showed an increase in a novel adipocyte derivative that did not accumulate lipids and that constituted approximately 80% of the mass of the tissue in Avy transgenic. A major effect of aP2-Ucp in brown fat was to reduce endogenous gene expression by as much as 95%. The results suggest that UCP synthesized from the aP2 gene promoter is thermogenically active and capable of reducing fat stores.

Adipose Tissue↗
PubMed1994

Light microscopic and three-dimensional morphology of the human muscular sarcocyst.

Established criteria for morphological typing of sarcocysts was applied to a large series of cases of human skeletal muscle sarcocystosis in Malaysia to determine the type of sarcocyst present. We also wanted to test the general usefulness of this classification and to determine if there are any new cyst types. Three-dimensional (3-D) reconstruction was done to see if the sarcocyst has a distinct 3-D morphology. A total of 66 sarcocysts from 21 cases of human muscle sarcocystosis obtained from a previous prevalence study were examined. Tissue sections (5 microns thick) were stained with haematoxylin and eosin and studied under the light microscope. For 3-D reconstruction, an image analyser was used to align and reconstruct the sarcocyst after microscopic images had been captured with a charge-coupled device (CCD) camera. All the cysts best fit into the type 4 category. This classification is generally useful, although cyst wall characteristics and zoite size appear to be the most reliable criteria for classification. The cyst width averaged 77 microns (range, 30-137.5 microns). Cyst walls were smooth, had no cytophaneres and were less than 1 micron thick. No secondary cyst wall or surrounding inflammation was evident. Numerous cyst merozoites with diameters averaging 1 micron filled the cyst lumen. Although septa were not apparent, in many cysts, zoites were arranged in a unique, curvilinear fashion that suggested their presence. 3-D reconstruction showed the sarcocyst to be a long, tortuous "cylinder" with no branching or other distinguishing feature.

Animals↗
PubMed1994

Inhibition of supraoptic vasopressin neurones following systemic clonidine.

Experiments were undertaken in urethane-anaesthetized rats to investigate the effects of systemic clonidine on the firing of supraoptic vasopressin (VP) neurones, which were identified by their characteristic phasic activity pattern. Injection of clonidine (50 micrograms/kg i.v.) reduced the firing of all 16 VP neurones tested, and their overall mean activity decreased from 5.09 +/- 1.01 to 1.63 +/- 0.64 spikes/second (P < 0.02). In VP cells which were already firing phasically before clonidine, the inhibition resulted in complete quiescence. In VP cells which were originally continuously active, the inhibition resulted in a switch to phasic activity. This inhibitory effect, which was prevented by prior injection of the alpha-2 antagonist idazoxan (0.5 mg/kg), had a mean duration of 11.8 +/- 1.8 min. Subsequent experiments revealed that i.v. clonidine (50 micrograms/kg) caused a transient rise in blood pressure, but this had a shorter time-course and was unlikely to account for the prolonged neuronal inhibition. It was concluded that systemic clonidine acts centrally to suppress the activity of hypothalamic VP neurones, thereby explaining the fall in plasma VP levels found in previous studies.

Animals↗
PubMed1994

The diagnosis and treatment of psoas abscess: a 12 year review.

Over a 12 year period, 25 psoas abscesses occurring in 17 patients were managed at Royal Perth Hospital (900 bed hospital). Symptoms were present, on average, for 5 weeks prior to diagnosis, which was typically confirmed by computerized tomography. Fifty-nine per cent of cases were primary and percutaneous drainage effected a cure in 80% of all cases. Percutaneous drainage resulted in a non-significant trend towards shorter inpatient stay.

Adult↗