Biomedical subjects
Publications and source records attributed to M Martin.
Two-particle correlations of direct photons were measured in central 208Pb+208Pb collisions at 158A GeV. The invariant interferometric radii were extracted for 100<K(T)<300 MeV/c and compared to radii extracted from charged pion correlations. The yield of soft direct photons, K(T)<300 MeV/c, was extracted from the correlation strength and compared to theoretical calculations.
The electronic or quantum control of individual molecules with the scanning tunnelling microscope offers exciting perspectives on operating molecular nanomachines. This implies the use of semiconductor surfaces rather than metallic surfaces which would rapidly quench the electronic excitations. We review recent results illustrating the state of the art and the main problems which need to be solved: the choice, design and properties of functionalized organic molecules on semiconductor surfaces; the control of the inelastic electronic channels through a single molecule; and the search for well-controlled atomic-scale wide-band-gap semiconductor surfaces.
The purpose of the study was to assess a large representative sample of cancer patients on distress levels, common psychosocial problems, and awareness and use of psychosocial support services. A total of 3095 patients were assessed over a 4-week period with the Brief Symptom Inventory-18 (BSI-18), a common problems checklist, and on awareness and use of psychosocial resources. Full data was available on 2776 patients. On average, patients were 60 years old, Caucasian (78.3%), and middle class. Approximately, half were attending for follow-up care. Types of cancer varied, with the largest groups being breast (23.5%), prostate (16.9%), colorectal (7.5%), and lung (5.8%) cancer patients. Overall, 37.8% of all patients met criteria for general distress in the clinical range. A higher proportion of men met case criteria for somatisation, and more women for depression. There were no gender differences in anxiety or overall distress severity. Minority patients were more likely to be distressed, as were those with lower income, cancers other than prostate, and those currently on active treatment. Lung, pancreatic, head and neck, Hodgkin's disease, and brain cancer patients were the most distressed. Almost half of all patients who met distress criteria had not sought professional psychosocial support nor did they intend to in the future. In conclusion, distress is very common in cancer patients across diagnoses and across the disease trajectory. Many patients who report high levels of distress are not taking advantage of available supportive resources. Barriers to such use, and factors predicting distress and use of psychosocial care, require further exploration.
Air density must be taken into account when ionization dosimetry is performed with unsealed ionization chambers. The German dosimetry protocol DIN 6800-2 states an air density correction factor for which current barometric pressure and temperature and their reference values must be known. It also states that differences between air density and the attendant reference value, as well as changes in ionization chamber sensitivity, can be determined using a radioactive check source. Both methods have advantages and drawbacks which the paper discusses in detail. Barometric pressure at a given height above sea level can be determined by using a suitable barometer, or data downloaded from airport or weather service internet sites. The main focus of the paper is to show how barometric data from measurement or from the internet are correctly processed. Therefore the paper also provides all the requisite equations and terminological explanations. Computed and measured barometric pressure readings are compared, and long-term experience with air density correction factors obtained using both methods is described.
BACKGROUND: Abdominal compartment syndrome (ACS) occurs when intra-abdominal pressure is abnormally high in association with organ dysfunction. It tends to have a poor outcome, even when treated promptly by abdominal decompression. METHODS: A search of the Medline database was performed to identify articles related to intra-abdominal hypertension and ACS. RESULTS: Currently there is no agreed definition or management of ACS. However, it is suggested that intra-abdominal pressure should be measured in patients at risk, with values above 20 mmHg being considered abnormal in most. Abdominal decompression should be considered in patients with rising pressure and organ dysfunction, indicated by increased airway pressure, reduced cardiac output and oliguria. Organ dysfunction often occurs at an intra-abdominal pressure greater than 35 mmHg and may start to develop between 26 and 35 mmHg. The mean survival rate of patients affected by compartment syndrome is 53 per cent. CONCLUSION: The optimal time for intervention is not known, but outcome is often poor, even after decompression. Most of the available information relates to victims of trauma rather than general surgical patients.
Amphipod survival in laboratory and in situ exposures was assessed using the eastern Pacific Haustoriid species Eohaustorius estuarius. Toxicity test results were compared using intact (unhomogenized) and homogenized sediment samples in both field and laboratory exposures. Experiments were conducted in Moss Landing Harbor, California, an impaired waterbody under 303 (d) of the US Clean Water Act. Synoptic laboratory and in situ sediment toxicity tests were conducted at two stations: Sandholdt Bridge (SB), the most contaminated station in the harbor, and at the South Jetty (SJ), a more marine station near the mouth of the harbor. We found that Eohaustorius is amenable to in situ testing. Despite highly variable field salinity regimes (6-32 PSU at SB and 21-34 PSU at SJ), in situ control survival was 87% and 84% at SB and SJ, respectively. Amphipod survival was lower in the in situ exposures relative to the laboratory exposures at both sites. Survival at SB was 30% and 76% in the homogenized in situ and laboratory samples, respectively, and 40% and 64% in the intact (unhomogenized) in situ and laboratory samples, respectively. Neither the homogenized or intact samples from the SJ station were toxic in laboratory experiments, but amphipod survival was only 40% in the intact in situ exposure at this station, possibly due to predation. These experiments suggest that the interaction of contaminants and variable physical parameters such as salinity and temperature may have resulted in lower survival in the in situ exposures. Sediment homogenization prior to in situ deployment may have reduced effects of predators in some samples.
The immobilization of recombinant cells by using the unstable 3,4-dihydroxyphenylacetate 2,3-dioxygenase was studied as a model. Dioxygenase activity and cell viability were compared in immobilized-cell systems and cells in suspension. Immobilization increased enzyme stability and the efficient degradation of 3,4-dihydroxyphenylacetate. The stability of the cloned enzyme and the viability of the immobilized recombinant cells were well maintained for at least 15 days. We used the strain Escherichia coli CC118-D in which the hpaB gene from Klebsiella pneumoniae, coding for the subunit of 3,4-dihydroxyphenylacetate 2,3-dioxygenase, was inserted into the chromosome. This study has demonstrated that the implementation of E. coli CC118-D in a pilot-scale bioreactor resulted in a 100% stabilization of dioxygenase activity, and could be a useful tool for bioremediation processes.
Tg2576 transgenic mice (mice overexpressing the "Swedish" mutation in the human amyloid precursor protein 695) demonstrated a decreased capacity for cell proliferation in the dentate gyrus of the hippocampus compared with non-transgenic littermates at 3 months, 6 months and 9 months of age. Isolation stress induced by individually housing each mouse from the time of weaning further decreased hippocampal cell proliferation in Tg2576 mice as well as in non-transgenic littermates at 6 months of age. Decreases in hippocampal cell proliferation in isolated Tg2576 mice were associated with impairments in contextual but not cued memory. Fluoxetine administration increased cell proliferation and improved contextual memory in isolated Tg2576 mice. Further, isolation stress accelerated the age-dependent deposition of beta-amyloid 42 plaques in Tg2576 mice. Numerous beta-amyloid plaques were found in isolated but not non-isolated Tg2576 mice at 6 months of age. These results suggest that Tg2576 mice, a mouse model of Alzheimer disease, have an impaired ability to generate new cells in the dentate gyrus of the hippocampus and that the magnitude of this impairment can be modulated by behavioral interventions and drugs known to have effects on hippocampal neurogenesis in normal rodents. Unexpectedly, isolation stress also appeared to accelerate the underlying process of beta-amyloid plaque deposition in Tg2576 mice. These results suggest that stress may have an impact on the underlying disease process associated with Alzheimer's disease.
The objective of this study was to compare the pre-weaning performance of pigs derived from cloned versus non-cloned parents. Five cloned gilts and one cloned boar were used to produce five litters of pigs. One of five cloned females and the cloned boar were derived from two genetically unmanipulated fetal fibroblast cell lines. The remaining female clones were derived from a fetal fibroblast cell line in which random insertion of a alpha-1,3-galactosyltransferase gene targeting construct had occurred. Fetal cell lines had similar genetic backgrounds and were derived from three different fetuses in three different litters. Five litters of pigs were also generated from matings between two non-cloned boars and five non-cloned gilts. The mean gestation length, mean litter size, mean birth and weaning weights for male and female pigs were similar for litters derived from cloned parents versus non-cloned parents. The proportions of pigs born live and pigs that survived to weaning were also similar for pigs born to cloned as compared to non-cloned parents. In summary, matings between cloned swine derived from fetal fibroblast cell lines yielded litters of pigs that were similar in the number born, piglet birth weight and perinatal and pre-weaning mortality to litters produced by non-cloned swine.
BACKGROUND: Traumatic lesion to the optic nerve often leads to severe and persistent functional loss. HISTORY AND SIGNS: A male patient was transferred to our hospital from the University Eye Clinic of Guadeloupe 5 days after ocular injury caused by a flying fish. Visual function was light perception. The anterior part of the eye and retina were unremarkable. A computer tomography disclosed a fracture of the sphenoid sinus, with a little bone fragment (DD: foreign body) located close to the optic nerve. THERAPY AND OUTCOME: Therapy had been started with Aminopenicillin combined with clavulan acid (Augmentin) i. v., 500 ml methylprednisolone (Solumedrol) i. v., lysine-acetyl salicylate (Aspegic) and topical application of dexamethasone combined with neomycin/polymyxin B (Maxitrol). We continued this therapy and intensified it by adding nimodipine (Nimotop) 30 1-1-1 and acetazolamide retard (Diamox sustet) 1-0-1. Unfortunately visual function did not recover under therapy. CONCLUSIONS: Traumatic lesions of the optic nerve head, especially when due to axial or tangential forces, can lead to severe and irreversible functional loss. Severe traumatic lesions, even bone fractures induced by flying fish are not a seldom encounter in the Caribbean Sea.
BACKGROUND: A prospective randomized clinical trial was implemented to assess whether the concomitant or the sequential addition of tamoxifen to chemotherapy provides improved clinical benefit in the adjuvant treatment of breast cancer in postmenopausal patients. PATIENTS AND METHODS: Four-hundred and eighty-five patients with node-positive operable disease were randomized to receive tamoxifen (20 mg/day) concomitantly (CON) or sequentially (SEQ) to EC chemotherapy (epirubicin 75 mg/m(2) + cyclophosphamide 600 mg/m(2) on day 1, every 21 days for four cycles). RESULTS: In the 474 fully evaluable patients there were 96 events; eight being second neoplasms and 88 being related to the breast cancer. Of these, 48 of 88 occurred in the CON arm and 40 of 88 in the SEQ arm. The Kaplan-Meier estimation of disease-free survival (DFS) at 5 years was 70% in the CON and 75% in the SEQ group (log-rank test, P = 0.43). Adjusted hazard ratio for treatment was 1.11 (95% confidence interval 0.71-1.73; P = 0.64). CONCLUSION: This study fails to show an advantage of one treatment arm over the other, but a trend, albeit non-significant, appears to favor the sequential addition of tamoxifen to epirubicin + cyclophosphamide and, as such, warrants further investigation.
OBJECTIVE: To assess whether infectious morbidity after total abdominal hysterectomy is decreased by the addition of 20 cc povidone-iodine gel at the vaginal apex after the usual vaginal preparation with povidone-iodine solution. STUDY DESIGN: Randomised controlled trial. SETTING: Fifteen secondary and tertiary hospitals in Canada. SAMPLE: A total of 1570 women undergoing planned total abdominal hysterectomy. METHODS: Computer-generated randomisation using a centralised telephone service was stratified by study centre with variable block size. In the operating room, a swab for bacterial vaginosis was taken before vaginal antisepsis. Study group remained concealed until the standard surgical preparation in the operating room was complete. Then povidone-iodine gel 20 cc was placed at the vaginal apex in the intervention group only. Participants were followed for one month post-operative. MAIN OUTCOME MEASURES: The primary outcome was post-operative infectious morbidity during the 30 days after surgery, defined as: febrile morbidity with hospital stay greater than five days or antibiotic treatment, or infection requiring readmission to hospital or additional visit. Other outcomes included abdominal wound infection, pelvic abscess and other pelvic infections. RESULTS: Post-operative infectious morbidity within 30 days occurred in 128/780 (16%) women receiving povidone-iodine gel preparation and 142/790 (18%) women not receiving gel (RR 0.9, 95% CI 0.7 to 1.1). Pelvic abscess was diagnosed in 0 patients in the gel group and in seven patients in the control group (P < 0.01). No significant difference was found in pelvic cellulitis (eight in each group) or abdominal wound infection (51 in the gel group and 58 in the control group, P= 0.5). CONCLUSION: Povidone-iodine vaginal gel antisepsis led to a 9% relative decrease in overall infectious morbidity after abdominal hysterectomy, which was not statistically significant. Povidone-iodine vaginal gel decreased the risk of pelvic abscess after total abdominal hysterectomy.
Two dogs, one immature and one adult, were presented with a history of progressive ascites. In a third, immature dog, increasing exercise intolerance had been noted. Echocardiography demonstrated a partition in the right atrium (cor triatriatum dexter) and echocontrast studies documented normal flow from the cranial vena cava into the right atrium and ventricle. A saphenous vein contrast study demonstrated flow from the caudal vena cava into an accessory right atrial chamber (sinus venarum). The sinus venarum communicated with the true right atrium via a small defect in the atrial membrane in one dog, and additionally with the left atrium via a right-to-left shunting foramen ovale in the other dogs. All defects were visualised on angiographic studies by selective catheterisation of the caudal vena cava via the femoral vein. Balloon dilatation of the defect was then performed using a small followed by a larger balloon angioplasty catheter to enlarge the defect in the atrial membrane. Clinical signs improved within days and were sustained in the long-term in all cases.
A retrospective study of 143 dogs with pericardial effusion is presented, including a statistical analysis of survival time. Cases were classified into those in which a mass was seen on echocardiography (echo-positive) and those in which no mass could be identified (echo-negative). Forty-four dogs were echo-positive and 99 were echo-negative. The median survival time (MST) was 1068 days for echo-negative dogs and 26 days for echo-positive dogs. Dogs with a history of collapse were more likely to present with a mass on echocardiography. Those presenting with collapse had an MST of 30 days compared with 605 days for those without collapse. Echo-negative dogs tended to present with ascites and generally had a larger volume of pericardial effusion. The median survival for dogs presenting with ascites was 605 days compared with 45 days for those without ascites. Among echo-negative dogs, 64 per cent had a relapse of their effusion. Subtotal pericardiectomy was performed in 31 echo-negative dogs. The procedure had a perioperative mortality of 13 per cent but provided a favourable long-term prognosis. Dogs undergoing pericardiectomy had a median survival of 1218 days compared with 532 days for those not undergoing surgery.
The records of 43 dogs presenting with severe pulmonic stenosis in which balloon valvuloplasty was attempted were reviewed. Thirty-four dogs (79 per cent) were symptomatic at initial presentation. All patients were selected for balloon valvuloplasty on the basis of a Doppler-derived trans-stenotic pressure gradient of over 80 mmHg and concurrent evidence of mild to severe right ventricular hypertrophy. Forty dogs underwent balloon valvuloplasty; the procedure was not performed in three dogs because of an aberrant coronary artery in two cases and because catheterisation of the pulmonary artery was not possible in the third. Overall, 37 out of the 40 dogs (93 per cent) were successfully ballooned, resulting in a mean reduction in the pressure gradient of 46 per cent, with a mean pressure gradient of 124 mmHg on presentation and 67 mmHg six months after the procedure. Three dogs died during balloon valvuloplasty (all of which had a concurrent defect) and three dogs showed a poor clinical response to the procedure. Thus balloon valvuloplasty was successful and resulted in a sustained clinical improvement in 80 per cent of previously symptomatic cases. This study was undertaken to document the results of balloon valvuloplasty in a larger population of dogs than has previously been published.
Diffuse Lewy body disease (DLBD) is a degenerative disease of the nervous system, involving the brain stem, diencephalic nuclei and cerebral cortex, associated with abnormal a-synuclein aggregation and widespread formation of Lewy bodies and Lewy neurites. DLBD presents as pure forms (DLBDp) or in association with Alzheimer disease (AD) in the common forms (DLBDc). Several neurotransmitter abnormalities have been reported including those of the nigrostriatal and mesocorticolimbic dopaminergic system, and central noradrenergic, serotoninergic and cholinergic pathways. The present work examines metabotropic glutamate receptor (mGluR) expression and signaling in the frontal cortex of DLBDp and DLBDc cases in comparison with age-matched controls. Abnormal L-[3H]glutamate specific binding to group I and II mGluRs, and abnormal mGluR1 levels have been found in DLBD. This is associated with reduced expression levels of phospholipase C beta1 (PLCbeta1), the effector of group I mGluRs following protein G activation upon glutamate binding. Additional modification in the solubility of PLCbeta1 and reduced PLCbeta1 activity in pure and common DLBD further demonstrates for the first time abnormal mGluR signaling in the cerebral cortex in DLBD. In order to look for a possible link between abnormal mGluR signaling and a-synuclein accumulation in DLBD, immunoprecipitation studies have shown alpha-synuclein/PLCbeta1 binding in controls and decreased alpha-synuclein/PLCbeta1 binding in DLBD. This is accompanied by a shift in the distribution of a-synuclein, but not of PLCbeta1, in DLBD when compared with controls. Together, these results support the concept that abnormal a-synuclein in DLBD produces functional effects on cortical glutamatergic synapses, which are associated with reduced alpha-synuclein/PLCbeta1 interactions, and, therefore, that mGluRs are putative pharmacological targets in DLBD. Finally, these results emphasize the emergence of a functional neuropathology that has to be explored for a better understanding of the effects of abnormal protein interactions in degenerative diseases of the nervous system.
MRI allows for the detection of mammographically and clinically occult breast neoplasms. We analysed the ability of MRI to detect occult breast cancer in three patients with Paget's disease of the nipple-areolar complex, proven histologically. In all three cases we observed differences in the morphological and dynamic features of healthy and pathological nipples, and we also found enhancement foci in breast tissue, with suspicious kinetic and morphological characteristics, which in the case of two patients corresponded to ductal carcinoma in situ. The detection and location with MRI of underlying neoplastic foci may be of help in choosing the most reasonable and conservative treatment in these patients.
We evaluated the effects of a plant extracts mixture (XT) standardized in 5% (wt/wt) carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin (oregano, cinnamon and Mexican pepper), alone or in combination with formic acid (FA), on the productive performance and the intestinal ecosystem of the early-weaned pig. Pigs weaned at 20 +/- 1 d of age (n = 216) were allocated in 24 pens and fed a standard medicated prestarter diet for 12 d. Twelve days after weaning, a stress management system based on social and dietary stress factors was applied to the animals, after which, each group was allocated to one of six dietary treatments, which followed a factorial arrangement, with three levels (as-fed basis) of the XT (0, 150, and 300 mg/kg) and two levels of FA (0 and 0.5%). On d 24 and 25 after the stress episode, eight pigs per treatment were killed to examine variables describing some aspects of the gastrointestinal ecology. Two days after the stress episode, an Escherichia coli K88 diarrhea episode occurred, and five casualties were registered. Four of the five deaths occurred in pens of pigs not fed the XT. The FA resulted in better G:F (P = 0.040) in coincidence with shorter villous height (P = 0.073) and lower rectal total microbial mass (P = 0.078). Both XT and FA addition increased stomach content (P = 0.006 and 0.003, respectively) and percentage of DM (P = 0.089 and 0.010, respectively), suggesting an increased gastric retention time; consequently, pH was also increased (P = 0.005 and 0.060, respectively). The XT decreased ileum total microbial mass (P = 0.025) and increased the lactobacilli:enterobacteria ratio (P = 0.002). The VFA profile in the cecum and colon was modified by XT inclusion, increasing the proportion of acetate (P = 0.018 and 0.025, respectively) and diminishing the proportion of butyrate (P = 0.096 and 0.040, respectively) and valerate (P = 0.001 and 0.039, respectively). Both XT and FA were shown to be effective in modifying the gastrointestinal ecosystem, stomach contents, and stomach emptying rate, which are proposed as important aspects in the mechanisms of action for these additives.