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Maffiuletti NA, Martin A, Babault N, Pensini M, Lucas B, Schieppati M. Electrical and mechanical H(max)-to-M(max) ratio in power- and endurance-trained athletes. J Appl Physiol (1985) 2001; 90:3-9. [PMID: 11133886 DOI: 10.1152/jappl.2001.90.1.3] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to compare the mechanical and electromyographic (EMG) characteristics of soleus motor units activated during maximal H reflex and direct M response among subjects with different histories of physical activity. Power-trained athletes produced stronger twitches, with a higher rate of twitch tension buildup and relaxation, than their endurance counterparts for both maximal H-reflex and maximal M-wave responses. The maximal H-reflex-to-maximal M-wave ratios for both force output (twitch) and EMG wave amplitude were significantly lower in power-trained than endurance-trained athletes. However, power-trained athletes exhibited a significantly greater twitch-to-EMG ratio for the reflexly activated motor units with respect to the entire motor pool, whereas endurance-trained athletes had comparable twitch-to-EMG ratios for both reflexly and directly activated units. Power training increases the force output of the whole ensemble of the motor units, thereby compensating for the lower efficacy of the reflex transmission between Ia spindle afferent input and soleus alpha-motoneuron. On the other hand, the lower level of force evoked by the reflexly activated units in endurance-trained athletes is associated with a greater motor pool reflex excitability. Therefore, endurance-trained athletes produce the necessary force by recruitment of more slow-twitch units than do other subjects for comparable levels of force and type of task.
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Martin A, Scahill L, Klin A, Volkmar FR. Higher-functioning pervasive developmental disorders: rates and patterns of psychotropic drug use. J Am Acad Child Adolesc Psychiatry 1999; 38:923-31. [PMID: 10405512 DOI: 10.1097/00004583-199907000-00024] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To explore the frequency, characteristics, and associated target symptoms of psychotropic drug use among subjects with higher-functioning pervasive developmental disorders (HFPDDs). METHOD A total of 109 children, adolescents, and adults (mean age = 13.9 years, SD = 6.9) consecutively seeking enrollment into the Yale Child Study Center's Project on Social Learning Disabilities were included in the study. Individuals in whom Asperger's disorder, autism, or pervasive developmental disorder-not otherwise specified had been previously diagnosed and who had a documented Full Scale IQ > or = 70 completed surveys on demographic, clinical, and medication history information. To naturalistically evaluate medication use patterns in this population, each drug class was analyzed with respect to demographic and clinical variables. RESULTS In all, 55% of subjects were taking psychotropics, with 29.3% taking 2 or more medications simultaneously. Antidepressants were the most commonly used agents (32.1%), followed by stimulants (20.2%) and neuroleptics (16.5%). The clinical presentation of subjects taking psychotropic agents was heterogeneous, and most consistently included anxiety-related target symptoms (in 65% of medicated individuals). CONCLUSIONS Psychotropic medication use appears to be common among subjects with HFPDDs, yet not generally based on the results of empirical research. Clinical heterogeneity among treated subjects suggests that psychiatric comorbidity may be overlooked in this population.
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Martin A, Frei B. Both intracellular and extracellular vitamin C inhibit atherogenic modification of LDL by human vascular endothelial cells. Arterioscler Thromb Vasc Biol 1997; 17:1583-90. [PMID: 9301639 DOI: 10.1161/01.atv.17.8.1583] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Oxidative modification of LDL by vascular cells has been proposed as a mechanism by which LDL becomes atherogenic. Antioxidants that can prevent LDL oxidation may therefore act as antiatherogens. We used endothelial cells (ECs) from human aortas (HAECs), human saphenous veins (HSECs), and bovine aortas (BAECs) to investigate the role of intracellular and extracellular vitamin C (ascorbate) in EC-mediated LDL modification. Incubation of LDL (0.1 mg protein per milliliter) with confluent HAECs in Ham's F-10 medium led to time-dependent modification of the lipoprotein. In contrast, incubation of LDL with HAECs in medium 199, which does not contain redox-active transition metal ions, did not lead to LDL modification. Both HAEC-mediated and cell-free LDL modifications in Ham's F-10 medium were strongly inhibited in a time- and dose-dependent manner by physiological concentrations of ascorbate. Confluent HAECs cultured under conventional conditions contained very little intracellular ascorbate (< 0.5 nmol/mg protein) but could be loaded with up to 20 nmol ascorbate per milligram protein in a time- and concentration-dependent manner. Ascorbate-loaded HAECs exhibited a lower capacity to modify LDL than did non-ascorbate-loaded control cells. When LDL was incubated with HSECs instead of HAECs, similar time- and concentration-dependent inhibitory effects on LDL modification of intracellular and extracellular ascorbate were observed. In contrast to human ECs, BAECs did not take up vitamin C and therefore only coincubation but not preincubation with ascorbate inhibited BAEC-mediated LDL modification. Our data show that enrichment of human vascular ECs with vitamin C lowers their capacity to modify LDL. In addition, extracellular vitamin C strongly inhibits EC-mediated, metal ion-dependent atherogenic modification of LDL.
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Gauthier A, Davenne D, Martin A, Cometti G, Van Hoecke J. Diurnal rhythm of the muscular performance of elbow flexors during isometric contractions. Chronobiol Int 1996; 13:135-46. [PMID: 8877122 DOI: 10.3109/07420529609037077] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The influence of time of day on elbow flexion torque was studied. Thirteen physical education students, 7 males and 6 females, made maximal and submaximal isometric contractions at 90 degrees of elbow flexors using a dynamometer. The torque developed was measured on each contraction. The myoelectric activity of the biceps muscle was also measured at the same time by surface electromyography (EMG) and quantified from the root mean square (RMS) activity. Torque and surface EMGs were measured at 6:00, 9:00, 12:00, 15:00, 18:00, 21:00, and 24:00 h over the same day. Oral temperature before each test session was measured on each occasion after a 30-min rest period. We observed a diurnal rhythm in elbow flexor torque with an acrophase at 18:00 h and a bathyphase at 6:00 h, in phase with the diurnal rhythm in oral temperature. However, the diurnal rhythm of temperature did not appear to have any influence on the torque. Links between neuromuscular efficiency and RMS/torque ratio were evaluated by measuring muscle activity along with torque. We also assessed variations in the level of maximal activity of the muscle under maximal voluntary contraction. Neuromuscular efficiency fluctuated during the day, with maximal and minimal efficiency at 18:00 h and 9:00 h, respectively, whereas activation level was maximal at 18:00 h and minimal at 9:00 h. The diurnal rhythm of torque was accounted for by variations in both central nervous system command and the contractile state of the muscle.
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Dierick M, Ravizza L, Realini R, Martin A. A double-blind comparison of venlafaxine and fluoxetine for treatment of major depression in outpatients. Prog Neuropsychopharmacol Biol Psychiatry 1996; 20:57-71. [PMID: 8861177 DOI: 10.1016/0278-5846(95)00292-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1. This was a randomized, double-blind comparison of the efficacy and safety of venlafaxine and fluoxetine in outpatients with major depression. 2. Three hundred fourteen patients were randomly assigned to either venlafaxine 37.5 mg twice daily or fluoxetine 20 mg once daily for a maximum of 8 weeks. 3. If the response was inadequate after two weeks of treatment, the dosage of venlafaxine could be increased to 75 mg twice daily. 4. A clinical response, defined as at least a 50% decrease from baseline in the total HAM-D score, was attained at week 6 in 72% of patients on venlafaxine and 60% of patients on fluoxetine (p = 0.023). 5. Among patients who increased their dose at 2 weeks, venlafaxine was significantly (p < 0.05) superior from week 3 onward on the HAM-D. 6. Venlafaxine 75 mg daily is comparable to fluoxetine, but at 150 mg daily, it may be superior to fluoxetine in outpatients with major depression who do not respond early to treatment.
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Wakarchuk W, Martin A, Jennings MP, Moxon ER, Richards JC. Functional relationships of the genetic locus encoding the glycosyltransferase enzymes involved in expression of the lacto-N-neotetraose terminal lipopolysaccharide structure in Neisseria meningitidis. J Biol Chem 1996; 271:19166-73. [PMID: 8702594 DOI: 10.1074/jbc.271.32.19166] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The biosynthetic function of the lgtABE genetic locus of Neisseria meningitidis was determined by structural analysis of lipopolysaccharide (LPS) derived from mutant strains and enzymic assay for glycosyltransferase activity. LPS was obtained from mutants generated by insertion of antibiotic resistance cassets in each of the three genes lgtA, lgtB, lgtE of the N. meningitidis immunotype L3 strain phi3 MC58. LPS from the parent strain expresses the terminal lacto-N-neotetraose structure, Galbeta1-->4GlcNAcbeta1-->3Galbeta1-->4Glc. Mild hydrazine treatment of the LPS afforded O-deacylated samples that were analyzed directly by electrospray ionization mass spectrometry (ESI-MS) in the negative ion mode. In conjunction with results from sugar analysis, ESI-MS revealed successive loss of the sugars Gal, GlcNAc, and Gal in lgt B, lgt A, and lgt E LPS, respectively. The structure of a sample of O- and N-deacylated LPS derived by aqueous KOH treatment of lgt B LPS was determined in detail by two-dimensional homo- and heteronuclear NMR methods. Using a synthetic beta-GlcNAc acceptor and a beta-lactose acceptor, the glycosyltransferase activities encoded by the lgtB and lgtA genes were unambiguously established. These data provide the first definitive evidence that the three genes encode the respective glycosyltransferases required for biosynthesis of the terminal trisaccharide moiety of the lacto-N-neotetraose structure in Neisseria LPS. From ESI-MS data, it was also determined that the Gal-deficient LPS expressed by the lgt E mutant is identical to that of the major component expressed by immunotype L3 galE-deficient strains. The galE gene which encodes for UDP-glucose-4-epimerase plays an essential role in the incorporation of Gal into meningococcal LPS.
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Ben-Smith A, Dove SK, Martin A, Wakelam MJ, Savage CO. Antineutrophil cytoplasm autoantibodies from patients with systemic vasculitis activate neutrophils through distinct signaling cascades: comparison with conventional Fcgamma receptor ligation. Blood 2001; 98:1448-55. [PMID: 11520794 DOI: 10.1182/blood.v98.5.1448] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In systemic vasculitis, interactions between antineutrophil cytoplasm autoantibodies (ANCAs) and neutrophils initiate endothelial and vascular injury. ANCAs directed against either myeloperoxidase (MPO) or proteinase 3 (PR3) can activate cytokine-primed neutrophils by binding cell surface-expressed MPO or PR3, with the concurrent engagement of Fcgamma receptors (FcgammaR). Because roles for phospholipase D (PLD) and phosphatidylinositol 3 kinase (PI3K) have been demonstrated in FcgammaR activation of neutrophils, this study investigated the hypothesis that ANCA stimulation of neutrophils involved a similar engagement of FcgammaR and activation of PLD and PI3K. Pretreatment of tumor necrosis factor (TNF) alpha-primed neutrophils with antibodies against FcgammaRII and FcgammaRIII inhibited MPO-ANCA and PR3-ANCA induced superoxide generation, confirming that FcgammaR ligation is involved in ANCA-mediated neutrophil activation. However, although stimulation of TNF-alpha-primed neutrophils by conventional FcgammaR ligation, either using antibody-mediated cross-linking of FcgammaR or aggregated IgG, induced PLD activation, ANCA stimulation did not. Moreover, although ANCA-induced neutrophil activation results in significant PI3K activation-as assessed by phosphatidylinositol 3,4,5-triphosphate generation-conventional FcgammaR ligation, but not ANCA, activates the p85/p110 PI3K subtype. Inhibition of ANCA-induced superoxide generation with pertussis toxin suggests that ANCAs activate the p101/p110gamma PI3K isoform. In addition, the kinetics of activation of protein kinase B differs between conventional FcgammaR ligation and ANCA stimulation of neutrophils. These results demonstrate that though ligation of FcgammaRIIa and FcgammaRIIIb may be necessary, it is likely that ANCAs require other membrane cofactors for neutrophil activation.
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Comparative Study |
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Horuk R, Martin A, Hesselgesser J, Hadley T, Lu ZH, Wang ZX, Peiper SC. The Duffy antigen receptor for chemokines: structural analysis and expression in the brain. J Leukoc Biol 1996; 59:29-38. [PMID: 8558064 DOI: 10.1002/jlb.59.1.29] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Duffy antigen receptor for chemokines (DARC) is expressed in human erythrocytes and on endothelial cells lining postcapillary venules in kidney and spleen. DARC is a promiscuous chemokine receptor and a binding protein for the malarial parasite Plasmodium vivax. The expression of DARC by subsets of endothelial cells and neurons in discrete anatomic sites in the brain suggests that this enigmatic receptor may have multiple roles in normal and pathological physiology. Conservation of this promiscuous chemokine binding function is evident from the similarity in nucleotide sequence of DARC homologues from multiple species, as well as the high-affinity binding of human chemokines to murine and avian erythrocytes. Analysis of the functional domains of DARC using chimeric receptors and and monoclonal antibodies to multiple extracellular domains localized chemokine binding to structures in the amino terminal extracellular domain (E1). Scatchard analysis demonstrated that a chimeric DARC receptor, composed of the E1 domain of DARC and the predicted hydrophobic helices and loops of interleukin-8RB (IL-8RB), bound IL-8, and MGSA with KD values almost identical to the wild type receptors and bound a repertoire of C-X-C and C-C chemokines characteristic of DARC. Although numerous reports have demonstrated that chemokines such as IL-8 are expressed in the brain, presumably by glial cells, little insight into the nature of their role in normal or pathological physiology in the nervous system has developed because the target cells that express the corresponding receptors have not yet been identified. Northern blotting experiments suggest that mRNA encoding DARC are expressed in the central nervous system, however, interpretation of this is unclear because of the ubiquitous expression of DARC lining postcapillary venules. This study provides direct evidence to localize expression of DARC in the central nervous system. Immunohistochemical examination of human archival sections of the brain with monoclonal antibodies specific for DARC localize expression of DARC to cell bodies and processes of Purkinjie cells in the cerebellum. The immunohistochemical findings were supported by analysis of chemokine binding and radioligand crosslinking with membranes made from various brain fractions. The hierarchical expression of DARC in neurons in the cerebellum suggest that chemokines may play an important role in the modulation of neuronal activity by glial cells.
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Review |
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Martin A, Wychowski C, Couderc T, Crainic R, Hogle J, Girard M. Engineering a poliovirus type 2 antigenic site on a type 1 capsid results in a chimaeric virus which is neurovirulent for mice. EMBO J 1988; 7:2839-47. [PMID: 2460345 PMCID: PMC457076 DOI: 10.1002/j.1460-2075.1988.tb03140.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Poliovirus type 2 (PV-2) Lansing strain produces a fatal paralytic disease in mice after intracerebral injection, whereas poliovirus type 1 (PV-1) Mahoney strain causes disease only in primates. Atomic models derived from the three-dimensional crystal structure of the PV-1 Mahoney strain have been used to locate three antigenic sites on the surface of the virion. We report here the construction of type 1-type 2 chimaeric polioviruses in which antigenic site 1 from the PV-1 Mahoney strain was substituted by that of the PV-2 Lansing strain by nucleotide cassette exchange in a cloned PV-1 cDNA molecule. These chimaeras proved to have mosaic capsids with composite type 1 and type 2 antigenicity, and induced a neutralizing response against both PV-1 and PV-2 when injected into rabbits. Moreover, a six-amino-acid change in PV-1 antigenic site 1 was shown to be responsible for a remarkable host-range mutation in so far as one of the two type 1-type 2 chimaera was highly neurovirulent for mice.
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Hood DW, Cox AD, Gilbert M, Makepeace K, Walsh S, Deadman ME, Cody A, Martin A, Månsson M, Schweda EK, Brisson JR, Richards JC, Moxon ER, Wakarchuk WW. Identification of a lipopolysaccharide alpha-2,3-sialyltransferase from Haemophilus influenzae. Mol Microbiol 2001; 39:341-50. [PMID: 11136455 DOI: 10.1046/j.1365-2958.2001.02204.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We have identified a gene for the addition of N-acetylneuraminic acid (Neu5Ac) in an alpha-2,3-linkage to a lactosyl acceptor moiety of the lipopolysaccharide (LPS) of the human pathogen Haemophilus influenzae. The gene is one that was identified previously as a phase-variable gene known as lic3A. Extracts of H. influenzae, as well as recombinant Escherichia coli strains producing Lic3A, demonstrate sialyltransferase activity in assays using synthetic fluorescent acceptors with a terminal galactosyl, lactosyl or N-acetyl-lactosaminyl moiety. In the RM118 strain of H. influenzae, Lic3A activity is modulated by the action of another phase-variable glycosyltransferase, LgtC, which competes for the same lactosyl acceptor moiety. Structural analysis of LPS from a RM118:lgtC mutant and the non-typeable strain 486 using mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy confirmed that the major sialylated species has a sialyl-alpha-(2-3)-lactosyl extension off the distal heptose. This sialylated glycoform was absent in strains containing a lic3A gene disruption. Low amounts of sialylated higher molecular mass glycoforms were present in RM118:lgtC lic3A, indicating the presence of a second sialyltransferase. Lic3A mutants of H. influenzae strains show reduced resistance to the killing effects of normal human serum. Lic3A, encoding an alpha-2,3-sialyltransferase activity, is the first reported phase-variable sialyltransferase gene.
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DellaSala DA, Martin A, Spivak R, Schulke T, Bird B, Criley M, van Daalen C, Kreilick J, Brown R, Aplet G. A Citizen's Call for Ecological Forest Restoration: Forest Restoration Principles and Criteria. ECOL RESTOR 2003. [DOI: 10.3368/er.21.1.14] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Martin V, Millet GY, Martin A, Deley G, Lattier G. Assessment of low-frequency fatigue with two methods of electrical stimulation. J Appl Physiol (1985) 2004; 97:1923-9. [PMID: 15258127 DOI: 10.1152/japplphysiol.00376.2004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
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 × gender × 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.
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Scaglioni G, Narici MV, Maffiuletti NA, Pensini M, Martin A. Effect of ageing on the electrical and mechanical properties of human soleus motor units activated by the H reflex and M wave. J Physiol 2003; 548:649-61. [PMID: 12588895 PMCID: PMC2342873 DOI: 10.1113/jphysiol.2002.032763] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study was designed to investigate the effect of ageing on the mechanical and electromyographic (EMG) characteristics of the soleus motor units (MUs) activated by the maximal Hoffmann reflex (Hmax) and by the direct muscle compound action potential (Mmax). Eleven young (mean age 25 +/- 4 years) and ten elderly (mean age 73 +/- 5 years) males took part in this investigation. The senior group presented lower amplitudes of Mmax (-57 %, P < 0.001) and Hmax (-68 %, P < 0.001) waves compared to the younger population. These were associated with a depression of relative twitch torque of the plantar flexors. The average values of the Hmax/Mmax ratio did not statistically differ between the two populations, despite a tendency for lower values (~23 %) in the senior group. However, the older adults showed a greater relative amplitude of the sub-maximal M wave evoked at Hmax (MatHmax) than did the younger males (young 5 % vs. elderly 29 % of the Mmax, P < 0.01). This finding suggests an increased homogeneity between the excitability threshold of sensory and motor axons. The twitch torque at Hmax (PtH-M) was subsequently calculated by subtraction from the total twitch torque of the mechanical contamination associated with MatHmax. The resulting PtH-M was significantly lower in the elderly (-59 %, P < 0.001). Despite a discrepancy of 20 % between the two groups, the mechanical ratio (PtH-M/PtM; PtM, twitch tension related to the Mmax compound action potential), like the EMG ratio, did not statistically differ between the young and older individuals. Nevertheless, the senior subjects exhibited a higher twitch/EMG ratio for the reflexively activated MUs (PtH-M/Hmax) than the younger individuals (+40 %, P < 0.05). This finding suggests an on-going neuromuscular remodelling, resulting in an increased innervation ratio. The neural rearrangement may be viewed as a compensatory adaptation of the motor system to preserve the mechanical efficiency of the surviving MUs, despite the age-related impairment of the segmental reflex system. This phenomenon is confirmed by the maintenance, with senescence, of the approximately constant values of the twitch/EMG ratio for the entire motor pool (PtM/Mmax).
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research-article |
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Martin A, Lachmann PJ, Halbwachs L, Hobart MJ. Haemolytic diffusion plate assays for factors B and D of the alternative pathway of complement activation. IMMUNOCHEMISTRY 1976; 13:317-24. [PMID: 820630 DOI: 10.1016/0019-2791(76)90341-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Cerulus F, Martin A. A lower bound for large angle elastic scattering at high energies. ACTA ACUST UNITED AC 1964. [DOI: 10.1016/0031-9163(64)90807-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Sabourin JC, Martin A, Baruch J, Truc JB, Gompel A, Poitout P. bcl-2 expression in normal breast tissue during the menstrual cycle. Int J Cancer 1994; 59:1-6. [PMID: 7927888 DOI: 10.1002/ijc.2910590102] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
bcl-2 is a proto-oncogene discovered through the t(14;18) translocation occurring in most human follicular lymphomas. The function so far attributed to bcl-2 is to counteract the occurrence of apoptosis and to prolong cell survival without affecting the cycling cells. Apoptosis has been described in normal breast tissue epithelial cells, and it peaks at the end of the luteal phase. We have studied bcl-2 expression by an immunohistochemical method in 50 samples of normal breast tissue distributed throughout the menstrual cycle. bcl-2 staining predominated in the lobular epithelial cells. It displayed a striking cyclic variation, with maximal expression at the mid-cycle period and a sharp decrease at the end of the cycle. These results strongly suggest that the regulation of bcl-2 expression in breast tissue is hormone-dependent. This could be of significance in tumorigenesis.
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Martin A. Representation of semantic and spatial knowledge in Alzheimer's patients: implications for models of preserved learning in amnesia. J Clin Exp Neuropsychol 1987; 9:191-224. [PMID: 2435755 DOI: 10.1080/01688638708405361] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Patients with Alzheimer's disease may exhibit severe, but variable patterns of cognitive deficits which can complicate and confound investigations of memory. Three patients are described with comparable levels of intellectual and memory abilities as assessed by the Wechsler scales. One patient (W) had a relatively circumscribed impairment of word-finding ability concurrent with intact visuospatial and constructional skill. Another patient (C) showed the opposite profile of abilities, while the third patient (G) exhibited deficits in both domains. All three patients were severely and globally amnesic when tested with traditional recall and recognition procedures. Patient W was able to demonstrate preserved semantic knowledge on a superordinate and category level but not for specific object attributes. Patient C demonstrated a remarkably preserved ability to generate and copy complex, meaningful, but not meaningless material. Corresponding profiles of preserved learning were revealed, but only under conditions that limited the demands on encoding and retrieval processes. Models were offered to account for these contrasting patterns of impairment. In addition, the possibility that medial temporal structures contribute to the ability to consciously reconstruct prior experiences was discussed.
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Wilson JF, Orpen JL, Bickle MJ, Hawkesworth CJ, Martin A, Nisbet EG. Granite-greenstone terrains of the Rhodesian Archaean craton. Nature 1978. [DOI: 10.1038/271023a0] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Martin A, Paruta AN, Adjei A. Extended Hildebrand Solubility Approach: methylxanthines in mixed solvents. J Pharm Sci 1981; 70:1115-20. [PMID: 7299644 DOI: 10.1002/jps.2600701007] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The solubility profiles of theobromine, theophylline, and caffeine at 25 degrees were examined in binary solvent systems including dioxane-formamide, water-polyethylene glycol 400, and glycerin-propylene glycol. Theobromine solubility was studied in dioxane-water mixtures, a solvent system that was investigated earlier for the solubility of theophylline and caffeine. Solubilities were calculated in these polar systems by a regression method, based on an extension of the Hildebrand-Scatchard equation of regular solution theory. A linear relationship between the mixed solvent solubility parameter, and dielectric constant, epsilon, was introduced earlier and was confirmed in the present study. In addition, it was observed that a regression of log (activity coefficient) on epsilon in a second or higher degree polynomial provides reasonable solubility values for the methylxanthines in mixed solvents. A direct regression of molal or mole fraction (but not molar) solubility against delta 1, epsilon, or against volume percent of one or the other solvent in a binary solvent mixture provided a suitable measure of solubility for these crystalline drugs in mixed polar solvents. The drug's solubility parameter as determined from peak solubility in mixed polar solvents varied somewhat, depending on the specific solvent system employed. It is suggested that a drug may exhibit one (or more) solubility parameters in nonpolar solutions and multiple solubility parameters in polar systems. The extended solubility approach serves for the back-calculation of solubilities in mixed solvent systems, even though the solubility parameter of the solute may vary from one solvent system to the next.
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Blanca M, Perez E, Garcia J, Miranda A, Fernandez J, Vega JM, Terrados S, Avila M, Martin A, Suau R. Anaphylaxis to amoxycillin but good tolerance for benzyl penicillin. In vivo and in vitro studies of specific IgE antibodies. Allergy 1988; 43:508-10. [PMID: 3232762 DOI: 10.1111/j.1398-9995.1988.tb01628.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Three patients are reported on who suffered anaphylactic reactions after amoxycillin (AX) treatment and challenge but tolerated benzylpenicillin (BP) parenterally and orally. Two of the three patients had positive skin tests and RAST to AX reagents but negative responses to benzyl penicilloyl (BPO) specific skin tests and RAST and the minor determinant mixture (MDM) skin test reagent. The third case was negative to all skin tests and RAST. RAST and RAST inhibition on the two positive sera suggest that the response is related to the acyl side chain of AX.
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Auberson G, Kinoshita T, Martin A. Violation of the Pomeranchuk Theorem and Zeros of the Scattering Amplitudes. Int J Clin Exp Med 1971. [DOI: 10.1103/physrevd.3.3185] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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MacDowell SW, Martin A. Unitarity Bounds of the Scattering Amplitude and the Diffraction Peak. ACTA ACUST UNITED AC 1964. [DOI: 10.1103/physrev.135.b960] [Citation(s) in RCA: 83] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Murry T, Madasu R, Martin A, Robbins KT. Acute and chronic changes in swallowing and quality of life following intraarterial chemoradiation for organ preservation in patients with advanced head and neck cancer. Head Neck 1998; 20:31-7. [PMID: 9464950 DOI: 10.1002/(sici)1097-0347(199801)20:1<31::aid-hed6>3.0.co;2-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Health-related quality of life (QOL) provides a measure of the patient's perception of his life after treatment. This study was undertaken to assess changes in QOL and swallowing in patients undergoing concurrent chemoradiotherapy (CR) for head and neck cancer. The assessment tools consisted of the Head and Neck Radiotherapy Questionnaire (HNRQ) and a swallowing questionnaire (SQ). METHODS The HNRQ and SQ were administered to a group of CR patients prior to treatment (n = 58), after the last week of treatment (n = 37), and 6 months after treatment (n = 27). Weight change was monitored in treatment subjects. RESULTS The results indicate that QOL and swallowing function decrease acutely during CR (p < .05) but improvement begins shortly after the treatment-related decline. At 6 months after CR, mean QOL exceeds pretreatment level. The oropharynx patients have the poorest outcome when compared with laryngeal and hypopharyngeal patients. A stronger correlation exists between swallowing and QOL at 6 months post-CR than during treatment (R = .52 versus R = .30). CONCLUSIONS Quality of life and swallowing are compromised in advanced head and neck cancer patients prior to treatment. There was a further decrease in QOL and swallow function during CR. Organ-preservation programs in head and neck cancer result in improved QOL and swallowing 6 months after treatment. The degree of improvement is site-specific.
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Dinca M, Fries W, Luisetto G, Peccolo F, Bottega F, Leone L, Naccarato R, Martin A. Evolution of osteopenia in inflammatory bowel disease. Am J Gastroenterol 1999; 94:1292-7. [PMID: 10235209 DOI: 10.1111/j.1572-0241.1999.01079.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Our aim was the assessment of frequency and evolution of osteopenia in patients with inflammatory bowel disease and identification of related factors. METHODS Bone mineral density (BMD) of the lumbar spine was measured in 54 patients with Crohn's disease (CD) and in 49 patients with ulcerative colitis (UC) and was repeated after a mean observation period of 21 (range, 8-50) months in 30 CD and 14 UC patients. Eighteen age-matched healthy subjects served as controls. Serum biochemistry (parathyroid hormone, osteocalcin, alkaline phosphatase, insulin-like growth factor 1, minerals, and markers of inflammation) was assessed at the time of the second BMD measurement. RESULTS Reduced BMD values were found in 48% of CD, and in 38% of UC patients. Compared with control subjects, the mean BMD was significantly lower in CD (p < 0.003) and UC (p < 0.0001) patients. BMD was positively correlated with the body mass index (p < 0.05) and inversely correlated with the lifetime steroid dose (p < 0.03). After 21 months the BMD of CD patients was virtually unchanged, with an annual variation (%deltaBMD/yr) of -0.31 +/- 0.49, whether treated with steroids or not, whereas in UC patients the BMD decreased significantly (p < 0.02) with a %deltaBMD/yr of -2.47 +/- 0.82 (p < 0.02 vis CD). This decrease can be attributed to steroid treatment. No biochemical alterations were detected in patients with rapid bone loss, compared with those with stable BMD. CONCLUSIONS Low bone density is frequent in both CD and UC, but apparently stable in CD. The evolution of BMD suggests that low bone density is associated with the pathogenesis of CD, whereas in UC it seems to be correlated with the side effects of corticosteroid treatment.
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