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Biomedical subjects

V Martin

Publications and source records attributed to V Martin.

At least 19 recordsLinked to original sources
PubMed2007

High prevalence of somatic symptoms and depression in women with disabling chronic headache.

OBJECTIVE: To better define, in women with headache, the relationship of depression and somatic symptoms to headache, characterized by diagnoses, frequency, and disability. METHODS: At six headache specialty clinics, women with headache were classified using ICHD-II criteria, and frequency was recorded. A questionnaire addressing demographics, age at onset of headache, headache-related disability, somatic symptom, and depression severity was completed. Logistic regression was performed to measure the associations of headache frequency and headache-related disability with somatic symptom and depression severity. RESULTS: A total of 1,032 women with headache completed the survey, 593 with episodic (96% with migraine) and 439 with chronic headache (87% with migraine). Low education and household income was more common in chronic headache sufferers and in persons with severe headache disability. Somatic symptom prevalence and severity was greater in persons with chronic headache and with severe headache-related disability. Significant correlation was observed between PHQ-9 and PHQ-15 scores (r = 0.62). Chronic headache, severe disability, and high somatic symptom severity were associated with major depressive disorder (OR = 25.1, 95% CI: 10.9 to 57.9), and this relationship was stronger in the subgroup with a diagnosis of migraine (OR = 31.8, 95% CI: 12.9 to 78.5). CONCLUSIONS: High somatic symptom severity is prevalent in women with chronic and severely disabling headaches. Synergistic relationship to major depression exists for high somatic symptom severity, chronic headache, and disabling headache, suggesting a psychobiological underpinning of these associations.

Activities of Daily Living↗
PubMed2006

An outbreak of East Coast Fever on the Comoros: a consequence of the import of immunised cattle from Tanzania?

In 2003 and 2004, a severe epidemic decimated the cattle population on Grand Comore, the largest island of the Union of Comoros. Fatalities started soon after the import of cattle from Tanzania. Theileria parva and its vector, Rhipicephalus appendiculatus, could be identified as the main culprits of the epidemic. Characterisation by multilocus genotyping revealed that the T. parva parasites isolated on the Comoros were identical to the components of the Muguga cocktail vaccine used in Tanzania to immunise cattle. Therefore, it is believed that East Coast Fever reached the Comoros while some of the imported livestock got infected in Tanzania by ticks of which the immature stadia fed on Muguga cocktail vaccinated animals. Since the Comorian government neither has the financial means nor the competent staff to pursue an adequate epidemiosurveillance, the danger exists that without external assistance and in a context of continuing globalisation more transboundary diseases will affect the Comorian livestock sector in the future.

Animals↗
PubMed2006

Viruses as quasispecies: biological implications.

During viral infections, the complex and dynamic distributions of variants, termed viral quasispecies, play a key role in the adaptability of viruses to changing environments and the fate of the population as a whole. Mutant spectra are continuously and avoidably generated during RNA genome replication, and they are not just a by-product of error-prone replication, devoid of biological relevance. On the contrary, current evidence indicates that mutant spectra contribute to viral pathogenesis, can modulate the expression of phenotypic traits by subpopulations of viruses, can include memory genomes that reflect the past evolutionary history of the viral lineage, and, furthermore, can participate in viral extinction through lethal mutagenesis. Also, mutant spectra are the target on which selection and random drift act to shape the long-term evolution of viruses. The biological relevance of mutant spectra is the central topic of this chapter.

Evolution, Molecular↗
PubMed2006

Chromosome band 6q deletion pattern in malignant lymphomas.

Deletion of chromosome arm 6q is a frequent karyotypic alteration found in a variety of cancers and lymphoproliferative disorders, including leukemia and lymphomas. We characterized 6q deletions in 35 malignant lymphomas, using conventional and molecular cytogenetic approaches, to define the deletion pattern of 6q in different histological types. Conventional cytogenetics revealed a 6q deletion in 46% of lymphomas, including two cases that showed 6q deletion as the sole chromosome anomaly. Interphase FISH analysis demonstrated allelic loss of 6q regions in 33 out of 35 cases (94.2%); the deletions were discontinuous, involving nonadjacent molecular regions. Although 6q deletion is a common event in all types of lymphomas, specific deletion patterns seem to characterize different histological types, suggesting that different tumor suppressor genes play different roles in different types of lymphomas. Two specific 6q regions deleted in diffuse large B cell lymphomas but not in follicular lymphomas may be implicated in the clinical transformation.

Chromosome Deletion↗
PubMed2006

Regional and international approaches on prevention and control of animal transboundary and emerging diseases.

Transboundary animal diseases pose a serious risk to the world animal agriculture and food security and jeopardize international trade. The world has been facing devastating economic losses from major outbreaks of transboundary animal diseases (TADs) such as foot-and-mouth disease, classical swine fever, rinderpest, peste des petits ruminants (PPR), and Rift Valley fever. Lately the highly pathogenic avian influenza (HPAI) due to H5N1 virus, has become an international crisis as all regions around the world can be considered at risk. In the past decades, public health authorities within industrialized countries have been faced with an increasing number of food safety issues. The situation is equally serious in developing countries. The globalization of food (and feed) trade, facilitated by the liberalization of world trade, while offering many benefits and opportunities, also represents new risks. The GF-TADs Global Secretariat has carried out several regional consultations for the identification of priority diseases and best ways for their administration, prevention and control. In the questionnaires carried out and through the consultative process, it was noted that globally, FMD was ranked as the first and foremost priority. Rift Valley fever, and today highly pathogenic avian influenza, are defined as major animal diseases which also affect human health. PPR and CBPP, a disease which is particularly serious in Africa and finally, African swine fever (ASF) and classical swine fever (CSF) are also regionally recognised as top priorities on which the Framework is determined to work. The FAO philosophy--shared by the OIE--embraces the need to prevent and control TADs and emerging diseases at their source, which is most of the time in developing countries. Regional and international approaches have to be followed, and the FAO and OIE GF-TADs initiative provides the appropriate concepts and objectives as well as an organizational framework to link international and regional organizations at the service of their countries to better prevent and control the risks on animal and human health and the economic impact of TADs and emerging animal diseases.

Animal Diseases↗
PubMed2006

Epidemiology and ecology of highly pathogenic avian influenza with particular emphasis on South East Asia.

Highly pathogenic avian influenza (HPAI) has been recognised as a serious viral disease of poultry since 1878. The number of recorded outbreaks of HPAI has increased globally in the past 10 years culminating in 2004 with the unprecedented outbreaks of H5N1 HPAI involving at least nine countries in East and South-East Asia. Apart from the geographical extent of these outbreaks and apparent rapid spread, this epidemic has a number of unique features, among which is the role that asymptomatic domestic waterfowl and more particularly free-ranging ducks play in the transmission of highly pathogenic H5N1. Field epidemiological studies have been conducted by the Food and Agriculture Organization and several collaborative centres to explore the factors that could have led to a change from infection to the emergence of widespread disease in 2003-2004 and 2005. Domestic waterfowl, specific farming practices and agro-ecological environments have been identified to play a key role in the occurrence, maintenance and spread of HPAI. Although there are some questions that remain unanswered regarding the origins of the 2004 outbreaks, the current understanding of the ecology and epidemiology of the disease should now lead to the development of adapted targeted surveillance studies and control strategies.

Agriculture↗
PubMed2005

Origin and evolution of highly pathogenic H5N1 avian influenza in Asia.

Outbreaks of highly pathogenic avian influenza caused by H5N1 viruses were reported almost simultaneously in eight neighbouring Asian countries between December 2003 and January 2004, with a ninth reporting in August 2004, suggesting that the viruses had spread recently and rapidly. However, they had been detected widely in the region in domestic waterfowl and terrestrial poultry for several years before this, and the absence of widespread disease in the region before 2003, apart from localised outbreaks in the Hong Kong Special Autonomous Region (SAR), is perplexing. Possible explanations include limited virus excretion by domestic waterfowl infected with H5N1, the confusion of avian influenza with other serious endemic diseases, the unsanctioned use of vaccines, and the under-reporting of disease as a result of limited surveillance. There is some evidence that the excretion of the viruses by domestic ducks had increased by early 2004, and there is circumstantial evidence that they can be transmitted by wild birds. The migratory birds from which viruses have been isolated were usually sick or dead, suggesting that they would have had limited potential for carrying the viruses over long distances unless subclinical infections were prevalent. However, there is strong circumstantial evidence that wild birds can become infected from domestic poultry and potentially can exchange viruses when they share the same environment. Nevertheless, there is little reason to believe that wild birds have played a more significant role in spreading disease than trade through live bird markets and movement of domestic waterfowl. Asian H5N1 viruses were first detected in domestic geese in southern China in 1996. By 2000, their host range had extended to domestic ducks, which played a key role in the genesis of the 2003/04 outbreaks. The epidemic was not due to the introduction and spread of a single virus but was caused by multiple viruses which were genotypically linked to the Goose/GD/96 lineage via the haemagglutinin gene. The H5N1 viruses isolated from China, including the Hong Kong SAR, between 1999 and 2004 had a range of genotypes and considerable variability within genotypes. The rising incidence and widespread reporting of disease in 2003/04 can probably be attributed to the increasing spread of the viruses from existing reservoirs of infection in domestic waterfowl and live bird markets leading to greater environmental contamination. When countries in the region started to report disease in December 2003, others were alerted to the risk and disease surveillance and reporting improved. The H5N1 viruses have reportedly been eliminated from three of the nine countries that reported disease in 2003/04, but they could be extremely difficult to eradicate from the remaining countries, owing to the existence of populations and, possibly, production and marketing sectors, in which apparently normal birds harbour the viruses.

Animals↗
PubMed2005

Why does knee extensor muscles torque decrease after eccentric-type exercise?

AIM: The purpose of this study was to re-examine central and peripheral origins of neuromuscular fatigue after a highly strenuous eccentric exercise of the knee extensor muscles (KE) using both voluntary/evoked contractions and electromyographic recordings (EMG). METHODS: Before, and 30 min after 15 min of intermittent one-logged downhill running, maximal percutaneous electrical stimulations (single twitch, 0.5 s tetanus at 20 Hz and 80 Hz) were applied to the femoral nerve of 10 male subjects. Electrically evoked superimposed twitches were delivered during isometric maximal voluntary contraction (MVC) to determine maximal voluntary activation (%VA). Vastus lateralis (VL), vastus medialis (VM) and biceps femoris (BF) EMG were recorded during MVC and quantified using the root mean square (RMS) value. M-wave characteristics were also determined. RESULTS: KE MVC and %VA decreased significantly with fatigue (-19.6+/-6.1%; P<0.001 and -7.8+/-6.6%; P<0.01, respectively). Peak tetanus tension at 20 and 80 Hz (P20 and P80, respectively) declined (P<0.001), concurrently with a decrement of the P20 x P80(-1) ratio (-37.3+/-16.6%; P<0.001). Antagonist muscle coactivation, RMS to M-wave peak-to-peak amplitude and MVC x P80(-1) ratios were unchanged after the fatiguing exercise. CONCLUSIONS: The results reveal that part of the large loss in MVC may have a central origin but most of the MVC decrement is due to the presence of low-frequency fatigue while possible contractile failure cannot be excluded.

Adult↗
PubMed2004

Assessment of low-frequency fatigue with two methods of electrical stimulation.

The aim of this study was to compare the use of transcutaneous vs. motor nerve stimulation in the evaluation of low-frequency fatigue. Nine female and eleven male subjects, all physically active, performed a 30-min downhill run on a motorized treadmill. Knee extensor muscle contractile characteristics were measured before, immediately after (Post), and 30 min after the fatiguing exercise (Post30) by using single twitches and 0.5-s tetani at 20 Hz (P20) and 80 Hz (P80). The P20-to-P80 ratio was calculated. Electrical stimulations were randomly applied either maximally to the femoral nerve or via large surface electrodes (ES) at an intensity sufficient to evoke 50% of maximal voluntary contraction (MVC) during a 80-Hz tetanus. Voluntary activation level was also determined during isometric MVC by the twitch-interpolation technique. Knee extensor MVC and voluntary activation level decreased at all points in time postexercise (P < 0.001). P20 and P80 displayed significant time x gender x stimulation method interactions (P < 0.05 and P < 0.001, respectively). Both stimulation methods detected significant torque reductions at Post and Post30. Overall, ES tended to detect a greater impairment at Post in male and a lesser one in female subjects at both Post and Post30. Interestingly, the P20-P80 ratio relative decrease did not differ between the two methods of stimulation. The low-to-high frequency ratio only demonstrated a significant time effect (P < 0.001). It can be concluded that low-frequency fatigue due to eccentric exercise appears to be accurately assessable by ES.

Adult↗
PubMed2004

Idiopathic hypertrophic pachymeningitis.

BACKGROUND: Hypertrophic pachymeningitis is an uncommon disorder that causes a localized or diffuse thickening of the dura mater and has been associated with rheumatoid arthritis, syphilis, Wegener's granulomatosis, tuberculosis, and cancer. Few series of the idiopathic variety have been described, particularly with respect to MRI correlation to clinical outcome and treatment. OBJECTIVE: To investigate the clinical and laboratory evaluation, course, and treatment of patients with idiopathic hypertrophic pachymeningitis (IHP), to correlate the MRI findings with the clinical course, and to review the literature on IHP. METHODS: Retrospective case series of 12 patients (9 men, 3 women), with a mean age of 55 years (range 39 to 88 years), who had IHP by imaging studies, meningeal or orbital biopsy, or both. The clinical features, laboratory evaluation, contrast-enhanced MRI, treatment, and clinical outcome were documented for each case. The mean duration of follow-up was 3.5 years (range 3 months to 16 years). RESULTS: The main clinical features at presentation were headache (11 cases), loss of vision (7 cases), diplopia (4 cases), papilledema (2 cases), other cranial nerve involvement (3 cases), ataxia (2 cases), and seizures (1 case). On the initial MRI, the location of abnormal enhancement of the dura mater correlated with the clinical findings and the sphenoid wing area was affected in all patients. The sedimentation rate was elevated in five cases. The CSF had increased protein in six cases and lymphocytosis in four cases. Biopsy of the dura mater in five cases and the orbital soft tissue in one case showed infiltrates of small mature lymphocytes, plasma cells, and epithelioid histiocytes, but no neoplasia, vasculitis, or infectious agents. Cultures of the CSF and biopsy material remained sterile. Corticosteroid therapy improved the vision in 7 of 8 cases and controlled headache in 10 of 11 cases. Five cases had partial improvement of other neurologic symptoms and signs. Recurrence developed with steroid tapering in six cases. One case had progressive deterioration and died. In four cases methotrexate or azathioprine was added with reduction of the steroid dose. Follow-up MRI performed in 11 patients correlated 80% with the clinical state (p = 0.01). CONCLUSION: IHP can be suspected on MRI and defined pathologically on biopsy. Untreated, the clinical course is usually marked by severe headache and progressive neurologic deterioration and vision loss. Although initially steroid-responsive, clinical manifestations frequently recur with corticosteroid taper, requiring the addition of immunosuppressive agents in some cases.

Adult↗
PubMed2004

Fatigue and recovery after high-intensity exercise part I: neuromuscular fatigue.

The contribution of central and peripheral factors to muscle fatigue were quantified following a high-intensity uphill running exercise. Eight male volunteers performed an intermittent exercise at 120 % of maximal aerobic speed on a treadmill with an 18 % grade. Electrically evoked and voluntary contractions of the knee extensors and EMG of the two vastii were analyzed before and immediately after the high-intensity exercise. Isometric maximal voluntary contraction decreased slightly (-7+/-8 %; p < 0.05) after exercise but no changes were found in the level of maximal activation or in the torque produced by a 80 Hz maximal stimulation applied to the femoral nerve. Following exercise, the single twitch was characterized by lower peak torque, maximal rate of force development, and relaxation (-28+/-11%, -25+/-12%, -31+/-15% respectively, p < 0.001), and higher surface of the M-wave for both vastii. The ratio between the torques evoked by 20 Hz and 80 Hz stimulation declined significantly (-22+/-10%, p < 0.01) after exercise. These findings indicate that muscle fatigue after high-intensity running exercise is due to significant alteration in excitation-contraction coupling and that this type of exercise does not induce significant central fatigue or changes at the crossbridge level.

Adult↗
PubMed2004

Fatigue and recovery after high-intensity exercise. Part II: Recovery interventions.

The purpose of this study was to determine the effect of three types of recovery intervention to neuromuscular function after high-intensity uphill running exercise. The 20-min recovery interventions were (i) passive, (ii) active (running at 50 % of maximal aerobic speed), and (iii) low-frequency electromyostimulation. Evoked twitch and maximal voluntary contractions of knee extensor muscles (KE) and EMG of the vastus lateralis and vastus medialis were analysed immediately after the exercise, 10 min after the end of the recovery periods, and 65 min after the exercise (Post65). An all-out running test was also performed 80 min after the end of the fatiguing exercise. No significant differences were noted in any measured parameters but a tendency to a better performance during the all-out test was found after the electromyostimulation intervention (297.5 +/- 152.4 s vs. 253.6 +/- 117.1 s and 260.3 +/- 105.8 s after active and passive recovery, p = 0.13 and p = 0.12, respectively). At Post65, isometric maximal voluntary contraction torque did not return to the pre-exercise values (279.7 +/- 86.5 vs. 298.7 +/- 92.6 Nm, respectively; p < 0.05). During recovery, electrically evoked twitch was characterized by an increase of peak torque, maximal rate of force development and relaxation (+ 24 - 33 %; p < 0.001) but these values were still lower at Post65 than pre-exercise. Amplitude and surface of the M-wave decreased during recovery. These results show that the recovery of the voluntary force-generating capacity of KE after an intermittent high-intensity uphill running exercise do not depend on the type of recovery intervention tested here. It can also be concluded that the recovery of twitch contractile properties does not necessarily follow that of maximal muscle strength.

Adult↗
PubMed2004

Triptans and CNS side-effects: pharmacokinetic and metabolic mechanisms.

Triptans are the treatment of choice for acute migraine. While seemingly a homogenous group of drugs, results from a meta-analysis reveal significant differences in efficacy and tolerability among oral triptans. The incidence of drug-related central nervous system (CNS) side-effects with some triptans is as high as 15% and may be associated with functional impairment and reduced productivity. The occurrence of adverse events associated with triptans in general, and CNS side-effects in particular, may lead to a delay in initiating or even avoidance of an otherwise effective treatment. Potential explanations for differences among triptans in the incidence of CNS side-effects may relate to pharmacological and pharmacokinetic differences, including receptor binding, lipophilicity, and the presence of active metabolites. Of the triptans reviewed, at clinically relevant doses, almotriptan 12.5 mg, naratriptan 2.5 mg and sumatriptan 50 mg had the lowest incidence of CNS side-effects, while eletriptan 40 and 80 mg, rizatriptan 10 mg and zolmitriptan 2.5 and 5 mg had the highest incidence. The most likely explanations for the differences in CNS side-effects among triptans are the presence of active metabolites and high lipophilicity of the parent compound and active metabolites. Eletriptan, rizatriptan and zolmitriptan have active metabolites, while lipophilicity is lowest for almotriptan and sumatriptan. If CNS side-effects are a clinically relevant concern in the individual patient, use of a triptan with a low incidence of CNS side-effects may offer the potential for earlier initiation of treatment and more effective outcomes.

Animals↗
PubMed2003

Intranasal sumatriptan in cluster headache: randomized placebo-controlled double-blind study.

BACKGROUND: Current evidence-based acute treatments of cluster headache are limited to oxygen inhalation and subcutaneous sumatriptan. Intranasal sumatriptan is a new formulation with better tolerability than the subcutaneous route. Two open-label studies suggested efficacy of intranasal sumatriptan in cluster headache. METHODS: In a double-blind placebo-controlled randomized trial, patients with episodic or chronic cluster headache whose attacks lasted at least 45 minutes each treated one attack with 20 mg sumatriptan nasal spray and another one, at least 24 hours later, with matching placebo. They scored their headache on a five-point scale (very severe, severe, moderate, mild, or none) at 5, 10, 15, 20, and 30 minutes. The primary outcome measure was headache response (a decrease in pain from very severe, severe, or moderate to mild or none) at 30 minutes. Secondary outcome measures included pain-free rates, relief of associated symptoms, and rates of adverse events. Multilevel multivariate analysis was used for statistical analysis. RESULTS: Five study centers enrolled 118 patients in whom 154 attacks were treated: 77 with sumatriptan and 77 with placebo. The responder rates at 30 minutes were 57% for sumatriptan and 26% for placebo (p = 0.002). Pain-free rates at 30 minutes were 47% for sumatriptan and 18% for placebo (p = 0.003). Sumatriptan was also superior to placebo considering initial response, meaningful relief, and relief of associated symptoms. There were no serious adverse events. CONCLUSION: Sumatriptan nasal spray is effective and well tolerated in the acute treatment of cluster headache attacks of at least 45 minutes' duration.

Administration, Intranasal↗
PubMed2003

Gas-phase detection of trinitrotoluene utilizing a solid-phase antibody immobilized on a gold film by means of surface plasmon resonance spectroscopy.

A multilayered biosensor was constructed and found to detect trinitrotoluene (TNT) in ppb concentrations in air both prior to and after detonation of TNT without use of a liquid phosphate buffered saline (PBS) superstrate. The biosensor surface was fabricated from a monoclonal antibody for TNT covalently bound to an 11,11'-dithio-bis(succinimidoylundecanoate) (DSU) self-assembled monolayer immobilized on a thin gold film bonded to a BK7 glass slide. The binding between the immobilized antibody and TNT antigen was detected using surface plasmon resonance spectroscopy (SPRS). Biosensor specificity for TNT was demonstrated with chemical homologues as well as against an unrelated explosive, RDX.

Air Pollutants↗
PubMed2003

Glutamate agonists release excitatory aminoacids from rat astrocytes.

Astrocytes release glutamate (Glu) by the mobilisation of intracellular concentrations of Ca++. The rationale of the present work was to test whether Glu and its agonists, known to affect intracellular Ca++ content via the activation of metabotropic and ionotropic receptors, could modulate the astrocytic release of excitatory aminoacids. NMR experiments showed that Glu released uniformly labelled [13C] Glu in the incubation medium of rat astrocytes in primary cultures. Further experiments confirmed this finding and showed that the incubation of these cells with agonists and antagonists of Glu ionotropic and metabotropic receptors, produced a different modulation of Glu and aspartate release. The observed activations of the various receptors suggest a complex modulation of the release of the excitatory aminoacids. Such a release of is interpreted in terms of metabolic microzonation.

Animals↗