Biomedical subjects

J Baker

Publications and source records attributed to J Baker.

At least 19 recordsLinked to original sources

PubMed2006

Small cell lung cancer treated in southeast Wales.

AIMS: In small cell lung cancer (SCLC), consolidation thoracic irradiation (CTI) increases 3-year absolute survival by 5.4% in patients with limited disease and a complete response to chemotherapy. Early concurrent thoracic radiotherapy has been shown to improve local control and prolong survival compared with CTI in some trials. The standard management of patients with SCLC in southeast Wales is CTI in individuals with limited disease and a complete response to chemotherapy. A review of patients with SCLC was carried out to establish whether survival locally is comparable with that reported in published studies, and if patients given CTI have survival comparable with that reported in studies where early concurrent thoracic radiotherapy was used. MATERIALS AND METHODS: Between January 2000 and December 2002, 303 patients were registered with SCLC in southeast Wales. One hundred and fifteen (47%) patients had limited disease and 60/115 (52%) received CTI. RESULTS: Patients with limited disease receiving CTI had a median survival of 17.7 months (95% confidence interval: 15-27.9 months). The 2- and 5-year survivals were 38 and 13%, respectively. CONCLUSIONS: These results compare favourably with previously published studies on SCLC. There are no plans to change our current treatment policy for SCLC in southeast Wales.

Adult↗

PubMed2006

Mortality in individuals with Type 2 diabetes and heart disease in a unique New Zealand population.

AIMS: To determine rate and predictors of mortality in patients with Type 2 diabetes living in a population with a large proportion of Maori and Pacific peoples who were admitted to hospital with myocardial infarction (MI) or congestive cardiac failure (CCF). METHODS: The study population included 4193 individuals with Type 2 diabetes who lived in South Auckland and who participated in a primary care audit between 1994 and 1999. We studied a subgroup of 319 patients who subsequently had a hospital admission for MI or CCF between 1999 and 2001. We examined their demographics, drug treatment, vascular risk factors and mortality up to 2003. RESULTS: Following discharge, the prescription of beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, aspirin and statins had all increased significantly. Vascular risk factors including total cholesterol, high-density lipoprotein (HDL) cholesterol, systolic blood pressure and glycated haemoglobin (HbA(1c)) improved significantly. Nevertheless, mortality remained high with individuals admitted because of an MI 7.2-fold more likely to die early and those with a CCF admission 5.9-fold more likely to die early than other individuals with Type 2 diabetes. Maori patients have an 80% excess mortality. CONCLUSIONS: Patients with past admission for MI and/or CCF remain at exceptionally high risk of death for at least 4 years after hospital admission, even with improvements in management of cardiovascular risk factors. Maori individuals are at particular risk.

Aged↗

PubMed2005

First results of the search for neutrinoless double-beta decay with the NEMO 3 detector.

The NEMO 3 detector, which has been operating in the Fréjus underground laboratory since February 2003, is devoted to the search for neutrinoless double-beta decay (beta beta 0v). The half-lives of the two neutrino double-beta decay (beta beta 2v) have been measured for 100Mo and 82Se. After 389 effective days of data collection from February 2003 until September 2004 (phase I), no evidence for neutrinoless double-beta decay was found from approximately 7 kg of 100Mo and approximately 1 kg of 82Se. The corresponding limits are T1/2(beta beta0v) > 4.6 x 10(23) yr for 100Mo and T1/2(beta beta 0v) > 1.0 x 10(23) yr for 82Se (90% C.L.). Depending on the nuclear matrix element calculation, the limits for the effective Majorana neutrino mass are < 0.7-2.8 e/v for 100Mo and < 1.7-4.9 eV for 82Se.

Journal Article↗

PubMed2005

Assessment of a point-of-care test for paracetamol and salicylate in blood.

BACKGROUND: Paracetamol and salicylate are commonly taken in acute overdose. Clinicians have a low threshold for excluding the presence of these two drugs, by ordering laboratory tests in any patient suspected of ingesting an overdose or with an altered mental state. AIM: To test the effectiveness of a new point of care test that qualitatively detects paracetamol and salicylate in blood and to examine the potential time saved by its use. DESIGN: Prospective multicentre trial. METHODS: The new test was compared with laboratory analysis in a routine blood sample taken from patients presenting to emergency departments with suspected overdose. RESULTS: The test had sensitivities of 98.5% and 88.5%, and specificities of 74.7% and 92%, for paracetamol and salicylate, respectively, at cut-off levels of 25 mg/l and 100 mg/l, respectively The point of care test results were available 2 h before the laboratory result. DISCUSSION: This point-of-care test could be used to rule out an overdose with either of these two drugs, and could thus lead to earlier clinical decisions for suspected overdose patients. Recommendations have been made following this trial that the cut-off value for paracetamol should be reduced from 25 mg/l to 12.5 mg/l in order to increase its usefulness. To prevent the test being misread, we also suggest that each device should be embossed to remind users that the presence of a line indicates there is no drug present.

Acetaminophen↗

PubMed2005

Ornithine transcarbamylase deficiency in pregnancy.

Women heterozygous for mutations at the ornithine transcarbamylase (OTC) locus may be at risk for hyperammonaemia and its untoward effects including coma and death in the postpartum period. We present the case of a pregnant woman heterozygous for OTC deficiency (McKusick 311250) whose past medical history was significant for two prior pregnancies complicated by postpartum hyperammonaemic coma. In the index pregnancy, increased levels of serum ammonium were noted during labour. Postpartum hyperammonaemia was averted by administration of oral sodium benzoate. Our experience demonstrates that in women at risk, perilous hyperammonaemia can be prevented through appropriate medical management.

Adult↗

PubMed2005

Antifungal constituents of northern prickly ash, Zanthoxylum americanum mill.

Leaf, fruit, stem, bark and root of Zanthoxylum americanum were investigated for antifungal activity with 11 strains of fungi representing diverse opportunistic and systemic pathogens, including Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. All extracts demonstrated a broad spectrum of antifungal activity and inhibited at least eight fungal species in a disk diffusion assay (600 microg/disk). Antifungal activity was light-dependent, with fruit and leaf extracts most active in general. The presence of light-mediated compounds, such as psoralen, 8-methoxypsoralen and imperatorin in extracts of different organs was confirmed by RP-HPLC. A high furanocoumarin content was detected in fruit and leaf and low furanocoumarin levels were found in bark and wood. A high positive correlation was observed between total furanocoumarin content and fungal inhibition zones (r2=0.902, p<0.001). The results provide a phytochemical basis for the very widespread use of Z. americanum in indigenous North American ethnomedical tradition for conditions that may be related to fungal infections.

Antifungal Agents↗

PubMed2005

The role of the retinoblastoma protein (Rb) in the nuclear localization of BAG-1: implications for colorectal tumour cell survival.

Although the retinoblastoma susceptibility gene RB1 is inactivated in a wide variety of human cancers, the retinoblastoma protein (Rb) has been shown to be overexpressed in colon cancers, which is linked to the anti-apoptotic function of the protein. However, the mechanisms by which Rb regulates apoptosis are yet to be fully elucidated. We have established that Rb interacts with the anti-apoptotic BAG-1 (Bcl-2 associated athanogene-1) protein, and that a decrease in nuclear localization of BAG-1 is detectable when the interaction between Rb and BAG-1 is disrupted by expression of the E7 viral oncoprotein. Interestingly, although reported as deregulated in colorectal cancers, we have found that BAG-1 expression is also altered in small adenomas, where its localization was found to be predominantly nuclear. In addition, we have established that maintenance of high nuclear BAG-1 in vitro increases the resistance of adenoma-derived cells to gamma-radiation-induced apoptosis. Our work suggests a novel function for Rb, involving modulation of the subcellular localization of BAG-1. We have found predominant nuclear BAG-1 localization in small adenomas, and suggest that BAG-1 may promote colorectal tumour cell survival by making colonic epithelial cells less sensitive to DNA damage.

Adenoma↗

PubMed2004

Nearest-neighbor-atom core-hole transfer in isolated molecules.

A new phenomenon sensitive only to next-door-neighbor atoms in isolated molecules is demonstrated using angle-resolved photoemission of site-selective core electrons. Evidence for this interatomic core-to-core electron interaction is observable only by measuring nondipolar angular distributions of photoelectrons. In essence, the phenomenon acts as a very fine atomic-scale sensor of nearest-neighbor elemental identity.

Journal Article↗

PubMed2004

Preliminary study of shunt related death in paediatric patients.

Hydrocephalus is a condition commonly encountered in paediatric and adult neurosurgery and cerebrospinal fluid (CSF) shunting remains the treatment of choice for many cases. Despite improvements in shunt technology and technique, morbidity and mortality remain. The incidence of early shunt obstruction is high with later failures seen less frequently. This review aims to examine mortality associated with mechanical failure of CSF shunts within Queensland. Neurosurgical and Intensive Care databases were reviewed for cases of mortality associated with shunt failure. Eight cases were identified between the years of 1992 and 2002 with the average age at death 7.7 years. Deaths occurred on average 2 years after last shunt revision. Seven of the eight patients lived outside the metropolitan area. Shunting remains an imperfect means of treating hydrocephalus. Mortality may be encountered at any time post surgery and delays to surgical intervention influence this. Alternative measures such as third ventriculostomy or the placement of a separate access device should be considered. In the event of emergency, a spinal needle could be used to access the ventricle along the course of the ventricular catheter.

Cerebrospinal Fluid Shunts↗

PubMed2004

The use and nursing management of benzodiazepines in acute, mental health inpatient care: a discussion.

The use of medication in acute mental health is common practice however, there is a lack of research into all aspects of pharmacology within inpatient settings. This paper explores the specific use of benzodiazepines and areas of potential mismanagement. A number of priorities for investigation are raised and implications for nursing roles and responsibilities discussed.

Acute Disease↗

PubMed2003

Dramatic nondipole effects in low-energy photoionization: experimental and theoretical study of Xe 5s.

The Xe 5s nondipole photoelectron parameter gamma is obtained experimentally and theoretically from threshold to approximately 200 eV photon energy. Significant nondipole effects are seen even in the threshold region of this valence shell photoionization. In addition, contrary to previous understanding, clear evidence of interchannel coupling among quadrupole photoionization channels is found.

Journal Article↗

PubMed2003

Self-organized superlattice formation during crystal growth from continuous beam fluxes.

Alloy superlattice structures consisting of alternating Si-rich and C-rich layers form spontaneously during gas-source molecular beam epitaxy of Si(1-y)C(y) on Si(001) from constant Si2H6 and CH3SiH3 precursor fluxes at T(s)=725-750 degrees C. The self-organized patterning is due to a complex interaction among competing surface reactions. During growth of the initial Si-rich layer, strain-driven C segregation to the subsurface results in charge transfer from surface Si atom dangling bonds to C backbonds. This decreases the Si2H6 sticking probability, and, hence, the instantaneous deposition rate, thereby enhancing C segregation. The Si-rich layer continues until a critical C coverage is reached allowing nucleation of a C-rich layer which grows until the excess subsurface C is depleted. The process then repeats with periods tunable through the choice of T(s) and y(avg).

Journal Article↗

PubMed2003

Blood pressure and rate pressure product response in males using high-dose anabolic androgenic steroids (AAS).

The literature regarding the blood pressure response to AAS use is equivocal. In addition, there is currently little data available on the Rate Pressure Product (RPP) response to anabolic androgenic steroids (AAS) use. The experimental aim of this study was to investigate the effects of AAS administration in combination with resistance training on blood pressure and rate pressure product in male amateur bodybuilders and compare the results with a morphologically matched, resistance trained control group. Subjects were divided into two groups (n=16 AAS users; n=16 controls). Systolic and Diastolic Blood Pressure, RPP. Resting Heart Rate and Body Composition measurements were obtained before (Pre), during (During) and 6-8 weeks following (Post) the AAS cycle in the AAS users with similar time intervals for the control group. No significant cardiovascular or morphological changes in the control group were found throughout the study. Significant increases in both diastolic (P<0.01) and mean arterial blood pressures (P<0.05) were found from Pre to Post cycle in the AAS group. RPP also increased significantly (P<0.01) from pre to post AAS cycle. All cardiovascular parameters returned to normal baseline measurements between 6 and 8 weeks post cycle. No blood pressure measurements throughout the study were consistent with clinically defined hypertension. The findings indicate that the AAS group exhibited significant increases in standard cardiovascular measurements compared with the control bodybuilders, and provides a contraindication to AAS use especially in borderline hypertensives.

Adult↗

PubMed2003

Opportunistic mycobacterial granuloma in a cat associated with a member of the Mycobacterium terrae complex.

An 18-month-old domestic short-haired neutered male cat presented with a nodular dermal thickening on a digit. Biopsy demonstrated pyogranulomatous inflammation with moderately frequent acid-fast bacilli. A member of theMycobacterium terrae complex was isolated. There was no evidence of systemic involvement. Treatment was initiated with enrofloxacin, rifampicin and clarithromycin. After 2 months there was no longer any clinically apparent dermal thickening. Treatment was continued for a further 3 months using enrofloxacin and rifampicin.

Animals↗

PubMed2003

East African running dominance revisited: a role for stereotype threat?

Regardless of the possible existence of physiological advantages in East African runners, belief that such differences exist creates a psychological atmosphere that can have significant consequences on performance. This is known as stereotype threat and can feature in many sports.

Africa, Eastern↗

PubMed2003

Estradiol plus progesterone treatment modulates select elements of the proinflammatory cytokine cascade in steers: attenuated nitric oxide and thromboxane B2 production in endotoxemia.

Estradiol plus progesterone (EP) implants have been shown to favorably alter the time course or decrease the severity of many of the clinical manifestations associated with coccidiosis and endotoxemia in calves. This study evaluated the effect of EP treatment on plasma tumor necrosis factor-alpha (TNF), thromboxane (TXB), prostacyclin (PRC), nitrite and nitrate (NO[x]), and cortisol. Holstein steer calves were divided into four groups: control, EP, endotoxin (LPS), and EP + LPS (n = five/group). Estradiol/progesterone pellets (Synovex-S) were implanted subcutaneously when calves reached 20 wk of age. One week after implantation, calves were injected i.v. with endotoxin (i.e., lipopolysaccharide; LPS, 0.6 microgram/kg of BW) or nonpyrogenic saline placebo. Body temperature was measured and blood was collected before injection and at 1, 2, 3, 4, 6, and 8 h thereafter. Plasma concentrations of TNF, cortisol, TXB, PRC, NO[x], were measured. Body temperature increased in both LPS and LPS-EP calves, but had returned to normal by 6 h in the LPS-EP group (P < 0.05). Plasma TNF and cortisol increased after LPS (P < 0.01), but were not differentially affected by EP treatment. Likewise, EP did not affect the magnitude of increase in LPS-induced PRC, but EP decreased the magnitude of increase in TXB (P < 0.05). Plasma NO[x]) levels were increased (P < 0.01) in calves after LPS; treatment with EP attenuated the LPS-associated increase in plasma NO[x] levels. These results suggest that EP exerts specific effects on different components of the proinflammatory cytokine cascade. Although the initiation of responses mediated by TNF, cortisol, and PRC do not seem to be differentially affected by EP, components of the nitric oxide- and TXB-axis responses to LPS are decreased in calves pretreated with EP.

Animal Feed↗

PubMed2002

Pharmacokinetics of phenylbutazone in beef steers.

Phenylbutazone was administered intravenously to a group of 11 beef steers at a dosage of 6 mg/kg of body weight. Whole plasma and protein-free plasma were analyzed for phenylbutazone residues. Pharmacokinetic parameters of total and free phenylbutazone in plasma were calculated using a noncompartmental method. In regards to whole plasma data, the mean volume of distribution at steady state (Vss), was 140 mL/kg body weight, with a mean (+/-SEM) terminal elimination half-life (t1/2) of 34 +/- 9 h. The mean clearance was 3.2 mL/h/kg body weight. The Vss, as determined from the protein-free plasma fraction, was 54093 mL/kg body weight. This larger Vss of free phenylbutazone compared with total plasma phenylbutazone was attributed to a high degree of plasma protein binding, as well as the greater penetration of free phenylbutazone into tissues. The mean t1/2 of free phenylbutazone was 35 +/- 12 h. This similarity to the t1/2 estimated from total plasma phenylbutazone data is attributed to an equilibrium between free and plasma phenylbutazone during the terminal elimination phase. The pharmacokinetic parameters of free and total plasma phenylbutazone in beef steers are statistically similar to those previously reported for lactating dairy cows.

Animals↗

PubMed2002

Outpatient intensive chemotherapy for small cell lung cancer: five years experience of modified 'ICE' ifosfamide carboplatin and etoposide.

INTRODUCTION: Small Cell Lung Cancer (SCLC) is increasingly being treated in the district general hospital setting. The search for an active regimen which can be given with the least toxicity and best outcomes led us to use a modified ICE (Ifosfamide, Carboplatin and Etoposide) regimen and modify it further by using oral mesna instead of intravenous mesna. METHOD: All patients selected to receive the modified ICE regime over a 5-year period were included in our study. All patients were assessed for performance status and prognostic factors. Only those with WHO performance status 0-1 and Manchester prognostic score 0-3 were considered for ICE chemotherapy. All patients were followed up for 1 year after recruitment was completed. RESULTS: Median survival for all 32 patients was 18.4 months (CI 12.2-24.6) and for the 28 patients with limited disease the median survival was 19.9 months (CI 8.2-31.6). Toxicity levels were low with no neutropenic deaths. One patient died three days after treatment was started due to disease progression. A total of 6 patients remained alive one year after recruitment was completed. Five out of the 6 were followed up for at least 2 years. CONCLUSION: Using this out-patient modified ICE regime we have achieved a median survival comparable to other active chemotherapy regimes for SCLC with no significant increase in toxicity.

Administration, Oral↗