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J M Brown

Publications and source records attributed to J M Brown.

At least 19 recordsLinked to original sources
PubMed2006

Detection of low-frequency lambda-doublet transitions of the free 12CH and 13CH radicals.

By Fourier transform microwave spectroscopy, lambda-doubling transitions of (12)CH and (13)CH in the lowest rotational levels of the X(2) product operator(1/2) ground state have been directly detected, which has not been done previously. For both radicals, hyperfine-split lines have been measured to an accuracy of better than 1 ppm between 3 and 15 GHz, an improvement of at least 2 orders of magnitude over previous laboratory data. The measured frequencies have been combined with all previous data for CH and (13)CH in the v = 0 level of the X(2) product operator electronic state to determine improved hyperfine parameters. The production of CH from various gases also has been studied and, with methanol, the yield of CH relative to OH. Astronomical studies of CH in higher rotational levels and (13)CH can now be undertaken on the basis of the present work.

Astronomical Phenomena↗
PubMed2006

Short-term costs of conventional vs laparoscopic assisted surgery in patients with colorectal cancer (MRC CLASICC trial).

The short-term clinical results of the CLASICC trial indicated that clinical outcomes were similar between laparoscopic and open approaches. This study presents the short-term (3 month) cost analysis undertaken on a subset of patients entered into the CLASICC trial (682 of 794 patients). As expected the costs associated with the operation were higher in the 452 patients randomised to laparoscopic surgery (lap) compared with the 230 randomised to open procedure (open), Pounds 1703 vs Pounds 1386. This was partially offset by the other hospital (nontheatre) costs, which were lower in the lap group (Pounds 2930 vs Pounds 3176). The average cost to individuals for reoperations was higher in the lap group (Pounds 762 vs Pounds 553). Overall costs were slightly higher in the lap group (Pounds 6899 vs Pounds 6631), with mean difference of Pounds 268 (95%CI -689 to 1457). Sensitivity analysis made little difference to these results. The cost of rectal surgery was higher than for colon, for lap (Pounds 8259 vs Pounds 5586) and open procedures (Pounds 7820 vs Pounds 5503). The short-term cost analysis for the CLASICC trial indicates that the costs of either laparoscopic or open procedure were similar, lap surgery costing marginally more on average than open surgery.

Colectomy↗
PubMed2005

A parallel approach to post source decay MALDI-TOF analysis.

We present a novel enhancement to matrix-assisted laser desorption ionization (MALDI) post-source decay (PSD) analysis whereby fragment ions from multiple precursor ions are acquired into the same spectrum without employing a timed ion gate to preselect each parent ion. Fragment ions are matched to their corresponding precursor ions by comparing spectra acquired at slightly different reflectron electric fields. By measuring the difference in time-of-flight (TOF) between the two spectra for each fragment, it is possible to calculate the mass of the fragment ion and its parent. This new "parallel PSD" technique reduces analysis time and consumes less sample than conventional PSD, which requires an ion gate for serial preselection of precursor ions.

Algorithms↗
PubMed2005

Bladder and sexual function following resection for rectal cancer in a randomized clinical trial of laparoscopic versus open technique.

BACKGROUND: Bladder and sexual dysfunction are recognized complications of mesorectal resection. Their incidence following laparoscopic surgery is unknown. METHODS: Bladder and sexual function were assessed in patients who had undergone laparoscopic rectal, open rectal or laparoscopic colonic resection as part of the UK Medical Research Council Conventional versus Laparoscopic-Assisted Surgery In Colorectal Cancer (CLASICC) trial, using the International Prostatic Symptom Score, the International Index of Erectile Function and the Female Sexual Function Index. Sexual and bladder function data from the European Organization for Research and Treatment of Cancer QLQ-CR38 collected in the CLASICC trial were used for comparison. RESULTS: Two hundred and forty-seven (71.2 per cent) of 347 patients completed questionnaires. Bladder function was similar after laparoscopic and open rectal operations for rectal cancer. Overall sexual function and erectile function tended to be worse in men after laparoscopic rectal surgery than after open rectal surgery (overall function: difference - 11.18 (95 per cent confidence interval (c.i.) -22.99 to 0.63), P = 0.063; erectile function: difference -5.84 (95 per cent c.i. -10.94 to -0.74), P = 0.068). Total mesorectal excision (TME) was more commonly performed in the laparoscopic rectal group than in the open rectal group. TME (odds ratio (OR) 6.38, P = 0.054) and conversion to open operation (OR 2.86, P = 0.041) were independent predictors of postoperative male sexual dysfunction. No differences were detected in female sexual function. CONCLUSION: Laparoscopic rectal resection did not adversely affect bladder function, but there was a trend towards worse male sexual function. This may be explained by the higher rate of TME in the laparoscopic rectal resection group.

Aged↗
PubMed2004

Maintenance treatment with interferon for advanced ovarian cancer: results of the Northern and Yorkshire gynaecology group randomised phase III study.

A randomised phase III trial was conducted to assess the role of interferon-alpha (INFalpha) 2a as maintenance therapy following surgery and/or chemotherapy in patients with epithelial ovarian carcinoma. Patients were randomised following initial surgery/chemotherapy to interferon-alpha 2a as 4.5 mega-units subcutaneously 3 days per week or to no further treatment. A total of 300 patients were randomised within the study between February 1990 and July 1997. No benefit for interferon maintenance was seen in terms of either overall or clinical event-free survival. We conclude that INF-alpha is not effective as a maintenance therapy in the management of women with ovarian cancer. The need for novel therapeutics or strategies to prevent the almost inevitable relapse of patients despite increasingly effective surgery and chemotherapy remains.

Adult↗
PubMed2003

Lack of communication between healthcare professionals and women with ovarian cancer about sexual issues.

Gynaecological cancer has been shown to affect women's sexual functioning, yet evidence suggests that healthcare professionals rarely discuss sexual issues with women diagnosed with a gynaecological cancer. Few studies have investigated why there is a lack of communication between healthcare professionals and women about sexual issues. Our study investigated the attitudes and behaviours of the 27 doctors and 16 nurses treating women with ovarian cancer in our centre towards the discussion of sexual issues, and also investigated women's experiences of such communication. Our findings showed that although most healthcare professionals thought that the majority of women with ovarian cancer would experience a sexual problem, only a quarter of doctors and a fifth of nurses actually discussed sexual issues with the women. Reasons for not discussing sexual issues included 'it is not my responsibility', 'embarrassment', 'lack of knowledge and experience' and 'lack of resources to provide support if needed'. While some of these reasons were also viewed as barriers by the women, the results demonstrate that there is a need from the women's perspective to improve communication about sexual issues, although the most appropriate approach to this remains to be investigated.

Adult↗
PubMed2003

Betamethasone in the last week of pregnancy causes fetal growth retardation but not adult hypertension in rats.

We tested the hypotheses that (1) maternal betamethasone (betaM) treatment over the range of clinical doses for prevention of prematurity-related pathologies from day 15 to 21 of rat gestation would produce growth retardation, and (2) the lowest betaM dose to produce growth retardation would result in hypertension in adult offspring. In experiment 1, pregnant Sprague-Dawley rats were administered betaM (0, 50, 100, 200, 400, or 600 microg/kg per day, subcutaneously) on days 15-21 of pregnancy and necropsied on day 21.5, with fetal lung and placental weights recorded. In experiment 2, two more groups of rats (0 or 100 microg/kg per day, subcutaneously) were allowed to deliver, and offspring were instrumented at 100 +/- 4 days of postnatal life with indwelling left carotid arterial catheters. After 48 hours of recovery, blood pressure was recorded continuously for 24 hours. In experiment 1, all newborn rats treated with betaM, and their placentas, except those receiving 50 microg/kg per day, were growth retarded in comparison with controls (P <.05). All treated lungs were smaller than those of controls (P <.05). In experiment 2, no differences were found in the mean arterial blood pressure of adult offspring given the lowest effective dose of betaM (100 microg/kg per day) compared with controls (114.2 +/- 5.3 mmHg versus 114.6 +/- 3.4 mmHg, respectively). These data suggest that glucocorticoids given in the last week of rat pregnancy in the lowest human clinical dose do not cause hypertension and somatic growth retardation. However, the presence of lung growth restriction at this dose argues for more studies on the efficacy of even lower concentrations for their ability to improve lung and other organ and tissue function while avoiding unwanted side effects.

Animals↗
PubMed2003

Characterization of expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in prostate cancer cell lines.

Stromal expression of some matrix metalloproteinases (MMPs) has been associated with increasing tumour burden in prostate cancer. We investigated the expression of mRNA (by RT-PCR) and protein (by zymography and western blotting) of MMPs and endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs) in two parent epithelial prostate cancer cell lines and sublines of increasing invasive/metastatic potential. Expression of membrane type MMPs, MT1-MMP and MT3-MMP mRNA was higher in PC3-derived than in LNCaP-derived lines, whereas MT2-MMP mRNA expression was higher in the LNCaPderived than in PC3-derived cell lines. Active MT1, MT2 and MT3-MMP protein levels were similar in all lines, but processed MT-MMPs, indicative of latent MMP activation, were increased in more aggressive sublines. Expression of MMP-1, MMP-13 and TIMP-1 was higher in the more aggressive sublines and may be implicated in invasive/metastatic ability. Regulation of MMP-1 and MMP-13 expression may offer important therapeutic options for treating patients with prostate cancer.

Biomarkers, Tumor↗
PubMed2003

Silica accelerated systemic autoimmune disease in lupus-prone New Zealand mixed mice.

The genetic backgrounds of lupus-prone murine models are a valuable resource for studying the influence of environmental exposure on autoimmune diseases in sensitive populations. Epidemiological studies have shown associations between silica exposure and several autoimmune diseases, including scleroderma and systemic lupus erythematosus. To determine whether silica exposure can exacerbate systemic autoimmunity in genetically predisposed animals, New Zealand mixed mice were intranasally instilled twice with saline or saline suspensions of 1 mg silica or 500 micro g TiO2, a dose equivalent in surface area, and were evaluated with respect to health and immune status. Survival in silica exposed NZM mice was decreased compared to saline and TiO2 exposed mice. Proteinuria levels were elevated in silica exposed mice. Levels of circulating immune complexes, autoantibodies to nuclear antigen (ANA), histone, and double stranded DNA were measured every two weeks by ELISA. Circulating immune complexes showed a trend towards an increased acceleration in levels in the silica exposed mice compared to saline and TiO2 exposed mice. ANA levels were significantly higher in silica exposed animals compared to saline and TiO2 exposed animals (0.237 +/- 0.03 versus 0.140 +/- 0.029 and 0.125 +/- 0.03, P < 0.05) 16 weeks postexposure. Autoantibodies to histone were also significantly elevated after 16 weeks in silica exposed animals compared to saline and TiO2 exposed animals (0.227 +/- 0.03 versus 0.073 +/- 0.015 and 0.05 +/- 0.03, P < 0.05). In contrast, serum IgG levels were decreased in silica exposed NZM mice compared to the saline controls, however, IgM levels were unaffected. Lungs of the silica-exposed mice had increased inflammatory infiltrates as well as fibrotic lesions characterized by excess collagen deposition. Therefore, although NZM mice are susceptible to SLE, silica exposure significantly exacerbated the course of disease.

Animals↗
PubMed2003

The innervation of FGF-induced additional limbs in the chick embryo.

Motoneurones that supply the vertebrate limb innervate their muscle targets in a highly reproducible manner. As development proceeds, these limb-specific motoneurones send out axons, which grow towards the developing limb and then congregate at its base to form the plexus. In the plexus, in response to unknown positional cues, these axons rearrange, often changing their original spatial relationships, before sorting out to emerge in the defined nerve trunks that innervate the limb. Several proposals have been put forward to explain how this reproducible innervation pattern is achieved. These include (1) that early differences in the motoneurone identity dictate their future axonal trajectories, (2) that axons actively respond to attractive or repulsive positional cues provided by the limb bud itself, or (3) that motor axons are passively deployed, following pathways of least mechanical resistance. We have addressed the question of the relative roles of motoneurone identity and the signals that the axons encounter on their journey towards the limb bud. Using the developing chick embryo as our experimental model we tested the effect of providing an additional limb target for motor axons leaving the flank level of the spinal cord. To do this we placed FGF-soaked beads in the presumptive flank of 2-day-old chick embryos. This treatment induces an additional limb containing muscles. We investigated whether such additional limbs are innervated and by which neurones. We show that rather than the additional limbs being solely supplied by axons diverted from the two existing limb plexuses, motoneurones that normally supply the flank alter their trajectories to enter the induced limb. Once in the limb, axons respond to positional cues within the bud to generate the stereotypical innervation pattern. Our results show that the tendency of 'flank' motoneurones to innervate flank can be overcome by the presence of an additional limb.

Animals↗
PubMed2002

Chromosome 3 linked frontotemporal dementia (FTD-3).

BACKGROUND: The authors have identified and studied a large kindred in which frontotemporal dementia (FTD) is inherited as an autosomal dominant trait. The trait has been mapped to the pericentromeric region of chromosome 3. METHODS: The authors report on the clinical, neuroimaging, neuropsychological, and pathologic features in this unique pedigree collected during 17 years of study. RESULTS: Twenty-two individuals in three generations have been affected; the age at onset varies between 46 and 65 years. The disease presents with a predominantly frontal lobe syndrome but there is also evidence for temporal and dominant parietal lobe dysfunction. Late in the illness individuals develop a florid motor syndrome with pyramidal and extrapyramidal features. Structural imaging reveals generalized cerebral atrophy; H2 15 O-PET scanning in two individuals relatively early and late in the disease shows a striking global reduction in cerebral blood flow affecting all lobes. On macroscopic pathologic examination, there is generalized cerebral atrophy affecting the frontal lobes preferentially. Microscopically, there is neuronal loss and gliosis without specific histopathologic features. CONCLUSIONS: FTD-3 shares clinical and pathologic features with other forms of FTD and fulfills international consensus criteria for FTD. There is involvement of the parietal lobes clinically, radiologically, and pathologically in FTD-3 in contrast to some forms of FTD. This more diffuse involvement of the cerebral cortex leads to a distinctive, global pattern of reduced blood flow on PET scanning.

Autopsy↗
PubMed2002

Computer-based quality of life questionnaires may contribute to doctor-patient interactions in oncology.

It is well recognized that oncologists should consider patients' quality of life and functioning when planning and delivering anticancer treatment, but a comprehensive assessment of how a patient feels requires a thorough inquiry. A standardized measurement of patients' quality of life may support clinicians in identifying important problems for discussion during the limited time of the medical consultations. The aim of this study was to assess the feasibility of computer-administered individual quality of life measurements in oncology clinics with immediate feedback of results to clinicians and to examine the impact of the information on consultations. The study employed a prospective non-randomized design with pre-test post-test within subjects comparisons and involved three medical oncologists and 28 cancer patients receiving chemotherapy. The intervention consisted of completion of quality of life questionnaires before the consultations and informing clinicians of the results. The main outcome measures were patients' perceptions of the content of baseline and intervention consultations and satisfaction with communication. A qualitative analysis of clinicians' interviews was performed. When clinicians had the quality of life results they enquired more often about daily activities (Z= -2.71, P=0.007), emotional problems (Z= -2.11, P=0.035) and work related issues (Z= -1.89, P=0.058). There was an increase in the number of issues discussed during the intervention consultation (Z= -1.89, P=0.059). Patients were highly satisfied with both consultations. The computer measurement was well accepted by patients who felt that the questionnaires were a useful tool to tell the doctors about their problems. The clinicians perceived that the quality of life data broadened the range of the clinical inquiry and helped them identify issues for discussion. Having symptoms and functional problems expressed quantitatively on a scale was useful for detection of change over time.

Adult↗
PubMed2002

Anticancer efficacy of systemically delivered anaerobic bacteria as gene therapy vectors targeting tumor hypoxia/necrosis.

A major obstacle in cancer gene therapy is selective tumor delivery. Previous studies have suggested that genetically engineered anaerobes of the genus Clostridium might be gene therapy vectors because of their ability to proliferate selectively in the hypoxic/necrotic regions common to solid tumors. However, the tumor colonization efficiency of the strain previously used was insufficient to produce any antitumor effect. Here we describe for the first time the successful transformation of C. sporogenes, a clostridial strain with the highest reported tumor colonization efficiency, with the E. coli cytosine deaminase (CD) gene and show that systemically injected spores of these bacteria express CD only in the tumor. This enzyme can convert the nontoxic prodrug 5-fluorocytosine (5-FC) to the anticancer drug 5-fluorouracil (5-FU). Furthermore, systemic delivery of 5-FC into mice previously injected with CD-transformed spores of C. sporogenes produced greater antitumor effect than maximally tolerated doses of 5-FU. Since most human solid tumors have hypoxic and necrotic areas this vector system has considerable promise for tumor-selective gene therapy.

Animals↗
PubMed2002

Sequence analysis of tau in familial and sporadic progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a tau deposition neurodegenerative disorder which usually occurs in sporadic form and is associated with a common variant of the tau gene. Rare familial forms of PSP have been described. Recently familial frontotemporal dementia linked to chromosome 17 (FTDP-17) has been shown to be due to mutations in tau and there may be a clinical and pathological overlap between PSP and FTDP-17. In this study we have analysed the tau sequence in two small families with PSP, and a number of clinically typical and atypical sporadic cases with pathological confirmation of the diagnosis. The tau mutations described in FTDP-17 were not found in the most clinically diagnosed patients with PSP. This suggests that usually FTDP-17 and PSP, including the rare familial form of PSP, are likely to be separate conditions and that usually PSP and typical PSP-like syndromes are not due to mutations in tau.

Aged↗
PubMed2002

Dynamic left ventricular outflow tract obstruction in critically ill patients.

OBJECTIVE: To review patients managed in an intensive care unit diagnosed with dynamic left ventricular outflow tract obstruction without hypertrophic cardiomyopathy. PATIENTS AND METHODS: Dynamic left ventricular outflow tract obstruction (DLVOTO) is characteristically associated with hypertrophic cardiomyopathy, although it has also been described in patients without this disorder. We reviewed patients managed in two intensive care units over a one year period who were hypotensive and/or resistant to catecholamine infusions. RESULTS: During the one year period nine critically ill patients were found on echocardiography to have DLVOTO. None of the patients had a prior history of hypertrophic cardiomyopathy (HOCM) or echocardiographic evidence of asymmetrical septal hypertrophy and in three patients HOCM was specifically excluded by prior or convalescent echocardiography or by post mortem analysis. We found the risk factors for DLVOTO included left ventricular hypertrophy, hypovolaemia and use of positive inotropic agents. All patients responded to an increase in intravascular volume, reduction in infused inotropic agents with one requiring metaraminol to maintain blood pressure. CONCLUSIONS: Dynamic left ventricular outflow tract obstruction without hypertrophic cardiomyopathy is not an uncommon cause of hypotension resistant to catecholamines in critically ill patients. The diagnosis is important because management which includes fluid loading, vasopressors and reducing catecholamine infusions, differs from the management of other causes of shock.

Journal Article↗
PubMed2001

Metabolism of tirapazamine by multiple reductases in the nucleus.

Tirapazamine (TPZ, 3-amino-1,2,4-benzotriazine 1,4-di-N-oxide, SR4233, Tirazone), a bioreductive drug currently in clinical trials, is selectively toxic to hypoxic cells commonly found in solid tumors. The toxicity results from the intracellular metabolism of TPZ to a highly toxic radical. When oxygen levels are low, the TPZ radical reacts with cellular molecules, producing DNA damage and cell death. The much lower toxicity towards aerobic cells results from the back-oxidation of the TPZ radical by oxygen. A major unresolved aspect of the mechanism of TPZ is the identity of the reductase(s) in the cell responsible for activating the drug to its toxic form. We have studied both the metabolism of the drug using HPLC and the formation of the TPZ radical with a fluorescence assay using dihydrorhodamine 123. We also measured DNA double- and single-strand breaks produced by TPZ, using the comet assay. We demonstrated that multiple reductases in the nucleus metabolize TPZ under hypoxia. Using the cofactor dependence of the reductases for metabolizing TPZ and of the DNA damage caused by TPZ, we show that DNA single-strand breaks after TPZ metabolism are probably caused by the most abundant source of reductase in the nucleus. DNA double-strand breaks, on the other hand, are formed by TPZ metabolism by an unknown nuclear reductase that requires only NADPH for its activity. This study is the first to characterize multiple nuclear reductases capable of activating TPZ.

Antineoplastic Agents↗