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Biomedical subjects

A Martin

Publications and source records attributed to A Martin.

At least 73 records · Page 4Linked to original sources

Cyclooxygenase-2 is expressed frequently and early in Barrett's oesophagus and associated adenocarcinoma.

AIMS: To establish the prevalence of cyclooxygenase-2 (COX-2) expression in a large series of resected Barrett's adenocarcinoma and associated preneoplastic lesions and to correlate this expression with clinicopathological data and prognosis. METHODS: COX-2 expression was assessed by immunohistochemistry in resected surgical specimens of 66 Barrett's adenocarcinomas and 32 cases of Barrett's mucosa (with dysplasia in 17 cases). RESULTS: Epithelial expression of COX-2 protein was increased in Barrett's mucosa compared with normal oesophagus. Epithelial expression of COX-2 was found in 91% of Barrett's specialized mucosa negative for dysplasia, 94% of Barrett's mucosa with dysplasia, and 97% of Barrett's adenocarcinoma. COX-2 expression was significantly higher in the well-differentiated adenocarcinomas when compared with the poorly differentiated tumours. There was no significant correlation between COX-2 expression and the other pathological features of the tumours. Survival analysis showed no significant prognostic value for COX-2. CONCLUSION: Our results confirm up-regulation of COX-2 in Barrett's oesophagus-metaplastic and dysplastic-and in Barrett's adenocarcinoma. Increased COX-2 expression did not differ during the progression from Barrett's oesophagus negative for dysplasia to Barrett's adenocarcinoma and is related to adenocarcinoma whose histology is well differentiated. This suggests that enhanced expression of COX-2 may occur early during Barrett's-associated neoplastic transformation.

Adenocarcinoma↗

Heterogeneous Epstein-Barr virus latent gene expression in AIDS-associated lymphomas and in type I Burkitt's lymphoma cell lines.

Epstein-Barr virus (EBV) is associated with lymphoma in immunocompromised patients. This study provides evidence that the expression of EBV nuclear antigen-3 genes can be directed from the F promoter in different type I Burkitt's lymphoma cell lines and in some lymphomas from human immunodeficiency virus-infected patients. This expression occurs predominantly after induction of the EBV lytic cycle.

Base Sequence↗

Low grade marginal zone B cell lymphoma of the breast associated with localised amyloidosis and corpora amylacea in a woman with long standing primary Sjögren's syndrome.

Primary low grade marginal zone B cell lymphoma (MZL) of the breast and localised mammary amyloidosis are exceedingly rare entities. This report describes the case of a woman with long standing Sjögren's syndrome presenting with asymptomatic MZL of the breast showing plasmacytic differentiation, associated with local ductular amyloidosis. The lesion was discovered incidentally in breast tissue resected for microcalcifications. Immunohistochemistry revealed kappa light chain restriction, supporting the neoplastic nature of the infiltrate. A retrospective molecular study of the salivary gland biopsy showed a B cell clone. This is the first report of the association of human mammary ductular amyloidosis with cartwheel shaped material identical to corpora amylacea, usually seen in brain, lung, and prostate, but unknown in the human breast. The excellent outcome without treatment seen in this patient further emphasises the need to distinguish between MZL with plasmacytic differentiation and extramedullary plasmacytoma.

Adult↗

Growth hormone-releasing hormone (GHRH) neurons in GHRH-enhanced green fluorescent protein transgenic mice: a ventral hypothalamic network.

The hypothalamic GHRH neurons secrete pulses of GHRH to generate episodic GH secretion, but little is known about the mechanisms involved. We have made transgenic mice expressing enhanced green fluorescent protein (eGFP) specifically targeted to the secretory vesicles in GHRH neurons. GHRH cells transported eGFP from cell bodies in the arcuate nucleus to extensively arborized varicose fiber terminals in the median eminence. Patch clamp recordings from visually identified GHRH cells in mature animals showed spontaneous action potentials, often firing in short bursts up to 10 Hz. GHRH neurons received frequent synaptic inputs, as demonstrated by the recording of abundant inward postsynaptic currents, but spikes were followed by large after-hyperpolarizations, which limited their firing rate. Because many GHRH neurons lie close to the ventral hypothalamic surface, this was examined by wide-field binocular epifluorescence stereomicroscopy. This approach revealed an extensive horizontal network of GHRH cells at low power and individual fiber projections at higher power in the intact brain. It also showed the dense terminal projections of the GHRH cell population in the intact median eminence. This model will enable us to characterize the properties of individual GHRH neurons and their structural and functional connections with other neurons and to study directly the role of the GHRH neuronal network in generating episodic secretion of GH.

Action Potentials↗

Adhesion measurements on the attachment devices of the jumping spider Evarcha arcuata.

The feet of the jumping spider Evarcha arcuata attach to rough substrates using tarsal claws. On smooth surfaces, however, attachment is achieved by means of a claw tuft, the scopula. All eight feet bear a tarsal scopula, which is equipped with setae, these again being covered by numerous setules. In E. arcuata, an estimated 624,000 setules, with a mean contact area of 1.7 x 10(5) nm(2), are present. The spider's entire contact area thus totals 1.06 x 10(11) nm(2). Adhesion to the substrate does not depend on the secretion of an adhesive fluid. Analysis via atomic force microscopy (AFM) shows that a single setule can produce an adhesive force (F(a)) of 38.12 nN perpendicular to a surface. Consequently, at a total F(a) of 2.38 x 10(-2) N and a mean body mass of 15.1 mg, a safety factor (SF; F(a)/F(m), where F(m) is weight) of 160 is achieved. Tenacity (tau(n); F(a)/A, where A is area of contact) amounts to 2.24 x 10(5) N m(-2).

Adhesiveness↗

Long-term survival of patients given hormonal therapy for metastatic endometrial stromal sarcoma.

Endometrial stromal sarcoma (ESS) is a rare neoplasm, mainly observed in premenopausal women. We describe two women 44 and 34 years old at the time ESS diagnosis, who developed lung metastases 3 and 6 years, respectively, after initial treatment: hysterectomy without (case 1) or with oophorectomy (case 2), followed by hormone replacement therapy (HRT) for the latter. Their estrogen (ER) and progesterone receptors (PR) were analyzed biochemically in metastatic lung tissue, yielding respective concentrations of ER 242 and 184, and PR 910 and 100 fmol/mg of cytosol protein. Both patients started treatment with the aromatase inhibitor aminoglutethimide (500 mg qid) after surgery for the first patient and after stopping HRT for the second. Under aromatase-inhibitor therapy, both patients achieved a complete response, patient 1 remains disease- free with 14+ years of follow-up, and patient 2 with 7+ years. Our data suggest that an aromatase inhibitor may be an effective treatment for ESS. Furthermore, routine ER and PR analyses could be useful to predict the response to hormonal therapy in ESS.

Adult↗

[Hairy cell leukemia, a reality in the Congo; apropos of 10 cases].

Hairy cell Leukaemia (HCL) is a rare chronic lymphoid hemoproliferation. Few studies have been carried out in this area in sub-Saharan Africa. Between January 1993 and December 1999, 10 cases (6 men and 4 women, average age: 43.3) of HCL were registered in the haematology service of the University hospital Centre of Brazzaville (UHCB). As far as the socio-professional and environmental risk is concerned, three patients have probably been exposed: one as a workman in wood working industry and the other two as exposed to hydrocarbons manipulation for at least ten years. Retroviral serology tests were negative for HIV and HTLV I/II. From a clinical standpoint, patients all presented large spleen, which was misinterpreted as being of malarial origin associated with severe pancytopenia. Histological and immunohistological assays were instrumental in making the correct diagnosis. Chemotherapy could not be systematically offered due to lack of means. Splenectomy was performed, and for 2 patients who were sent abroad, this was followed by administration of interferon alpha. This study once again highlights the difficulty of clinical management of malign hemopathies in sub-Saharan Africa.

Adolescent↗

Potential role for advanced trauma life support programme in improving trauma care in Jamaica.

Data from the Road Safety Unit in the Ministry of Transport and Works, Jamaica, show an increase in road traffic accidents from 7861 in 1991 to 11,010 in 1999. The average number of deaths annually was 380 +/- 48 (SD) while injuries averaged 3320 +/- 262 per year. This represents an injury to death ratio of 8.7 compared with 24.9 for Trinidad and Tobago and 40 for Canada. During the period 1991 to 2000, an average of 796 +/- 159 (SD) murders were committed annually. The number of murders increased by over 280 per cent between the decade of the seventies and the nineties. Data from the trauma registry of the University Hospital of the West Indies showed that 29.6 per cent of all admissions to the surgical ward between January 1998 and December 31, 2000, were due to injuries. There were 97 deaths (3%) during this period and 33 occurred in the Accident and Emergency Department with 70 per cent occurring within 120 minutes of their arrival. The Advanced Trauma Life Support (ATLS) Programme emphasizes the resuscitation and stabilization of injured patients in the first few hours after injury. Most Emergency Departments in Jamaica are staffed by relatively junior medical officers and the low injury to death ratio among victims of motor vehicle accidents may be due to suboptimal care. Introduction of an ATLS programme in Jamaica may reduce the number of preventable deaths and also stimulate interest in trauma care thus increasing preventative measures to decrease the high incidence of trauma in Jamaica.

Accidents, Traffic↗

[Lactate measurements and acid-base balance in cord blood].

OBJECTIVE: To compare two techniques of lactate measurements in cord blood: either by electrochemical strip method with Lactate Pro of KDK in the umbilical artery alone (series 1) or by enzymatic method with Rapid lab Analyzer of Bayer in the two vessels (series 2) with acid base balance being also determined. SUBJECTS AND METHODS: Series 1 included 353 neonates with a mean gestational age of 37 (+/- 3.6) weeks and series 2 included 410 newborns with a mean gestational age of 38 (+/- 3.1) weeks. RESULTS: Data was presented as mean and SD. In the first series mean umbilical artery lactate concentration was 3.71 (+/- 1.81) mmol/l. In the second series mean umbilical artery blood gas and lactate levels were as follows: pH = 7.25 (+/- 0.9), pCO2 = 6.55 (+/- 1.39) kPa; BD = 6.61 (+/- 3.33) mmol/l, lactate 3.92 (+/- 1.81) mmol/l. The 3rd percentile of pH was 7.05 whereas the 97th percentile of lactate was 7.54 mmol/l. There was a close correlation between lactate and pH, and lactate and BD. Lactate concentration was higher in case of instrumental delivery compared to spontaneous one: 4.65 versus 3.76 mmol/l (p = 0.0001, Student test). No perfect correlation was found between lactate level and neonatal outcome but there was not a significant number of neonates with immediate complication. CONCLUSION: Lactate measurements obtained with single use strip method are valuable and easy to perform.

Acid-Base Equilibrium↗

Optimization of the biodegradation of naphthalene by a microorganism isolated from petroleum contaminated soil.

Response surface methodology (RSM) was used to optimise the process parameters to obtain maximum biodegradation of naphthalene. The factorial design employed, a face-centred cube, helped in identifying the combined best parameter conditions. Naphthalene-containing medium was inoculated with Pseudomonas fluorescens and incubated at different levels of agitation, pH, and temperature, and analyzed by Gas Chromatography-Mass Spectroscopy. As a result of the optimisation process, the process parameters found for maximum degradation of naphthalene by P. fluorescens were an agitation speed of 186 rpm, a pH of 7.3, and a temperature of 22.8 degrees C.

Biodegradation, Environmental↗

Influence of cycling cadence on neuromuscular activity of the knee extensors in humans.

The aim of the present study was to investigate the influence of pedalling rate and power output in cycling on the neuromuscular activity of the knee extensor muscles. Ten subjects took part in 15 randomised trials, which consisted of three levels of power outputs (60%, 80% and 100% maximal aerobic power) and five cadences (70%, 85%, 100%, 115% and 130% of the freely chosen cadence, FCC). Root mean square (rms) was utilized to quantify electromyographic activity of the vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) muscles. The mean (SD) FCC did not change with power output, ranging from 85.0 (11.9) to 88.0 (11.1) rpm. A significant power effect ( P<0.01) for the rms of VL, VM and RF muscles was observed. Results showed no significant cadence effect on neuromuscular activity of the VL and VM muscles, while the rms of the RF muscle was significantly greater ( P<0.05) at 70% FCC when compared to other cadences. In conclusion, the neuromuscular activity of the knee extensor muscles was not significantly influenced by cadence manipulations. Thus, minimisation of the neuromuscular activity of these muscles would not seem to lead to the choice of a cadence in cycling.

Adult↗

Wetting transitions at soft, sliding interfaces.

We observe (by optical interferometry) the contact of a rubber cap squeezing a nonwetting liquid against a plate moving at velocity U. At low velocities, the contact is dry. It becomes partially wet above a threshold velocity V(c1), with two symmetrical dry patches on the rear part. Above a second velocity V(c2), the contact is totally wet. This regime U>V(c2) corresponds to the hydroplaning of a car (decelerating on a wet road). We interpret the transitions at V(c1), V(c2) in terms of a competition between (a) liquid invasion induced by shear (b) spontaneous dewetting of the liquid (between nonwettable surfaces).

Journal Article↗

Triglyceride, cholesterol and weight changes among risperidone-treated youths. A retrospective study.

The purpose of this retrospective chart review was to assess triglyceride, cholesterol and weight changes among risperidone-treated youths. The charts of 22 child and adolescent inpatients were abstracted. The sample's mean (+/- SD) age was 12.8 (+/- 2.6) years, daily risperidone dose 2.7 (+/- 2.2) mg, and average length of exposure 4.9 (+/- 1.0) months. Repeated measures analysis of variance revealed statistically and clinically significant weight gain averaging 7.0 (+/- 4.7) kg (95% confidence interval [CI] for the mean = 4.9,9.1; F = 49.421, df = 1,21, p < 0.001). No significant changes in serum triglyceride or cholesterol levels were seen in the group as a whole. Triglyceride levels and weight were strongly correlated with each other: almost 25% of the variance in triglyceride level changes could be explained by weight gain alone (R2 = 0.22, F = 5.526, p = 0.029), although such association weakened when excluding subjects (N=5) concurrently treated with lithium or divalproex (R2 = 0.06, p > 0.05). On the basis of this preliminary report it seems prudent to be clinically vigilant and conservative, recommending regular laboratory monitoring until a clearer picture emerges regarding lipid dysregulation associated with risperidone and other atypical antipsychotic use in children and adolescents.

Adolescent↗

Improving risk assessment: hip geometry, bone mineral distribution and bone strength in hip fracture cases and controls. The EPOS study. European Prospective Osteoporosis Study.

Hip geometry and bone mineral density (BMD) have previously been shown to relate independently to hip fracture risk. Our objective was to determine by how much hip geometric data improved the identification of hip fracture. Lunar pencil beam scans of the proximal femur were obtained. Geometric and densitometric values from 800 female controls aged 60 years or more (from population samples which were participants in the European Prospective Osteoporosis Study, EPOS) were compared with data from 68 female hip fracture patients aged over 60 years who were scanned within 4 weeks of a contralateral hip fracture. We used Lunar DPX 'beta' versions of hip strength analysis (HSA) and hip axis length (HAL) applied to DPX(L) data. Compressive stress (Cstress), calculated by the HSA software to occur as a result of a typical fall on the greater trochanter, HAL, body mass index (BMI: weight/(height)2) and age were considered alongside femoral neck BMD (FN-BMD, g/cm2) as potential predictors of fracture. Logistic regression was used to generate predictors of fracture initially from FN-BMD. Next age, Cstress (as the most discriminating HSA-derived parameter), HAL and BMI were added to the model as potentially independent predictors. It was not necessary to include both HAL and Cstress in the logistic models, so the entire data set was examined without excluding the subjects missing HAL measurements. Cstress combined with age and BMI provided significantly better prediction of fracture than FN-BMD used alone as is current practice, judged by comparing areas under receiver operating characteristic (ROC) curves (p<0.001, deLong's test). At a specificity of 80%, sensitivity in identification was improved from 66% to 81%. Identifying women at high risk of hip fracture is thus likely to be substantially enhanced by combining bone density with age, simple anthropometry and data on the structural geometry of the hip. HSA might prove to be a valuable enhancement of DXA densitometry in clinical practice and its use could justify a more proactive approach to identifying women at high risk of hip fracture in the community.

Absorptiometry, Photon↗

In-situ comparative mapping (ISCM) of Glu-1 loci in Triticum and Hordeum.

The ability to detect small low- or single-copy DNA sequences by fluorescence in-situ hybridization (FISH) is an important step towards physical mapping of plant genomes. In this study, the FISH technique was used to physically map the Glu-1 loci controlling high-molecular weight (HMW) glutenin in common wheat (Triticum aestivum cv. 'Chinese Spring') and tritordeum (an amphiploid between T. turgidum cv. durum and Hordeum chilense). The probe used was the single-copy Glu-D1-1d gene coding the 1Dx5 HMW glutenin subunit. Three loci were mapped on chromosomes of wheat homoeologous group 1 (arm 1AL, 1BL and 1DL). The Glu-1 loci were mapped (fraction of the distance from the centromere) at positions 0.76 +/- 0.01, 0.69 +/- 0.01 and 0.76 +/- 0.01, on arms 1AL, 1BL and 1DL, respectively. The Glu-1 loci were also mapped on chromosomes of homoeologous group 1 of tritordeum at positions 0.75 +/- 0.01, 0.70 +/- 0.01 and 0.60 +/- 0.01, on arms 1AL, 1BL and 1HchL, respectively. Chromosomes with positive signals were identified by reprobing chromosome preparations using both the GAA-satellite and pAs1 sequences simultaneously. The application of the FISH technique to study homoeology among different genomes is discussed.

Chromosome Mapping↗

Increased visceral fat distribution in drug-naive and drug-free patients with schizophrenia.

OBJECTIVE: To investigate visceral fat distribution in patients with schizophrenia. DESIGN: Cross sectional study using CT scanning in patients with drug-naive and drug-free schizophrenia. SUBJECTS: Fifteen (13 men and two women) subjects with schizophrenia (mean age 33.7 y; mean body mass index (BMI)=26.7 kg/m(2)), and 15 age- and sex-matched controls (mean age 30.5 y; mean BMI=22.8 kg/(2)). MEASUREMENTS: Various fatness and fat distribution parameters (by CT scanning and anthropometry) and 16:00 h plasma cortisol. RESULTS: In comparison to controls, patients with schizophrenia had central obesity and had significantly higher levels of plasma cortisol. Furthermore, previous neuroleptic exposure did not appear to influence these findings as both drug-naive and drug-free patients had equally high levels of visceral fat deposition. CONCLUSION: Central obesity is a well recognized risk factor in developing certain general medical conditions. This study shows that patients with schizophrenia have increased intra-abdominal fat which may provide one explanation for why they die prematurely.

Abdomen↗

First-trimester features of Fowler syndrome (hydrocephaly-hydranencephaly proliferative vasculopathy).

We describe the features of Fowler syndrome (proliferative vasculopathy and hydrocephaly-hydranencephaly) diagnosed in the first trimester. The pregnancy with no significant family history was referred for karyotyping and ultrasound examination after a cystic hygroma was seen at 12 weeks. At 13 weeks, ultrasound examination revealed hydrocephaly-hydranencephaly, fetal akinesia, and arthrogryposis associated with increased nuchal translucency. The parents opted for termination of pregnancy and the diagnosis of Fowler syndrome was confirmed by pathological examination of the fetus. Calcified necrotic lesions and proliferative vasculopathy were observed in the entire central nervous system including the brainstem and spinal cord. Cases previously reported in siblings suggest an autosomal recessive transmission but specific genetic antenatal diagnosis is not yet available. The diagnosis of proliferative vasculopathy and hydrocephaly-hydranencephaly (Fowler syndrome) should be considered whenever hydrocephaly-hydranencephaly associated with a fetal akinetic sequence are encountered at the end of the first trimester. Genetic counseling is recommended.

Adult↗