PubMed Health⌕ Search

Biomedical subjects

M Maillet

Publications and source records attributed to M Maillet.

At least 19 recordsLinked to original sources
PubMed2002

Spontaneously chosen crank rate variations in submaximal arm exercise with inexperienced subjects. Effects on cardiorespiratory and efficiency parameters.

The aim of the present study was to compare the physiological responses during arm exercises when the crank rate was chosen spontaneously (TS) or set at +/- 20 % (T-20, T+ 20) of the spontaneously chosen crank rate (SCCR). Eight physical education male students, aged 22 +/- 3.2 years, performed an upper body exercise in which intensities ranged from unload to 80 % of maximal power. No significant difference was observed in oxygen uptake, ventilation, gross and net efficiency values between TS and T+ 20 or T-20. Nevertheless, oxygen uptake and ventilation were significantly (p < 0.05) lower and gross and net efficiencies higher (p < 0.05) during T-20 than T+ 20. No significant difference was noticed for heart rate, delta and work efficiency between TS, T-20 and T+ 20. The hypothesis that SCCR is the most economical one according to the efficiency parameters was not quite verified. However, crank rates lower than SCCR could be interesting because they increase gross efficiency compared to higher crank rates. Moreover, the selection of crank rates depends on power output. Indeed, SCCR increased significantly (p < 0.05) with power output. In the physical reconditioning of injured or handicapped subjects, the latter are very sensitive to the power output, and the crank rate could be another constraint.

Adult↗
PubMed2000

Nongenomic actions of estrogens and xenoestrogens by binding at a plasma membrane receptor unrelated to estrogen receptor alpha and estrogen receptor beta.

The molecular mechanism used by environmental chemicals to exert their hormone-like actions is still only partially resolved. Although it generally is accepted that xenoestrogens act at the genomic level by binding to intracellular estrogen receptors, we have shown here that they trigger nongenomic effects in pancreatic beta cells. Both xenoestrogens and the circulating hormone, 17beta-estradiol, bind with high affinity to a common membrane binding site unrelated to the intracellular estrogen receptors ERalpha and ERbeta. This binding site is shared by dopamine, epinephrine, and norepinephrine and has the pharmacological profile of the gammaadrenergic receptor. This study provides an outline of the membrane receptor involved in rapid xenoestrogen actions.

Animals↗
PubMed2000

Histopathologic findings in cutaneous cytomegalovirus infection.

When cytomegalovirus (CMV) involves the skin, viral inclusions are typically present within mesenchymal cells, e.g., endothelial cells, fibrocytes, and sometimes within inflammatory cells, e.g., macrophages, in contrast to infection in other organs in which inclusions are usually present within ductal epithelial cells. Two cases of cutaneous CMV are presented, one showing prominent findings within eccrine ductal epithelium and the other revealing mostly endothelial cells affected by CMV. Due to the range of cytologic changes induced by CMV observed in these cases, there seem to be early, fully developed, and late cellular changes brought about by CMV analogous to how herpesvirus (varicella, zoster, simplex) induces different changes depending on its stage of infection.

Adult↗
PubMed1999

[Reconstruction of the anterior cruciate ligament: arthrotomy versus arthroscopy].

The aim of this study was to compare the results of arthroscopic with open arthrotomy reconstruction of the anterior cruciate ligament, as treatment of chronic anterior laxity. 54 knees (among 63) were evaluated, 33 reconstructions were performed according to Kenneth Jones technique with arthrotomy (from 1990 to may 1993) and 21 were arthroscopically-assisted (from may 1993 to 1996). Meniscectomy was associated respectively in 22 and 7 cases. The average interval between initial injury and surgery was 18 and 18.6 months. Follow-up was one year at least. We evaluated mobility, amyotrophy and quadriceps and hamstrings muscular deficit: static at 1 month and using Cybex isokinetic tests at 2, 3 and 6 months and 1 year. Postoperative residual laxity and Arpege cotation were evaluated at 1 year. Student and Mann Whitney tests were used for statistical evaluation. As complication we noted respectively after arthrotomy and after arthroscopy: 7 (21.2 p. 100) and 4 (19 p. 100) algodystrophy, 1 (3 p. 100) and 1 (4., 7 p. 100) Cyclops syndrome, and 2 (6 p. 100) and 1 (4.7 p. 100) anterior knee pain. Lack of extension and flexion were respectively -5.4 degrees/130 degrees and -1.9 degrees/136 degrees at 3 months (p = 0.04) and -3.5/134 degrees and -1.5 degrees/138 degrees at 6 months (not significative). At 1 month, static hamstrings deficit was 41.3 p. 100 after open arthrotomy and 29.6 p. 100 after arthroscopic assisted (p = 0.05). At 2 months, isokinetic hamstrings deficit was lower after arthroscopic assisted (21.6 p. 100 at 60 degrees; 20.8 p. 100 at 180 degrees) than after open arthrotomy (32.8 p. 100; 32.5 p. 100) (p = 0.039 and 0.008). This difference was found for hamstrings until 3 months. At 6 months and 1 year, no difference was found for Cybex tests. In Arpege score, at 1 year, 73.3 p. 100 were very satisfied or satisfied after open arthrotomy and 77.7 p. 100 after arthroscopy. Global results were excellent or good in 66 p. 100 after open arthrotomy and 83 p. 100 after arthroscopy. Radiological laxity was less than 5 mm in 88 p. 100 after open arthrotomy and 92 p. 100 after arthroscopic assisted. So, after arthroscopically assisted procedure, the number of algodystrophy and anterior knee pain was lower, and until 3 months, range of motion was better and hamstrings deficit was lower. After 6 months, difference about range of motion or muscular deficit were not significative. At 1 year, after arthroscopic procedure, results seemed better with a lower rate of residual laxity and better global results, but the number of medial meniscectomies was lower in this group. In conclusion, the arthroscopic-assisted procedure seems to allow a faster rehabilitation.

Adolescent↗
PubMed1997

The active site region of the vitamin K-dependent carboxylase includes both the amino-terminal hydrophobic and carboxy-terminal hydrophilic domains of the protein.

In order to localize the active site of the vitamin K-dependent carboxylase, we developed an affinity probe containing the propeptide and the first two carboxylatable glutamate residues conserved in many native substrates. This probe crosslinked to both the hydrophobic amino-terminal and hydrophilic carboxy-terminal domains of the carboxylase, in contrast with previous work which localized both the catalytic and the propeptide binding site within the amino-terminal hydrophobic domain. Amino acid analysis revealed that the mass of an amino-terminal fragment is seriously underestimated by SDS-PAGE. Reanalysis of the published data in light of this information suggests that a portion of the propeptide binding site resides within the carboxy-terminal hydrophilic domain.

Amino Acid Sequence↗
PubMed1997

[Ultrastructure of the kidney in paraquat-poisoned rats. Comparative study with literature data on man and animal].

This study was designed to assess the effect of paraquat on the rat kidney. The experimental animals used were Wistar rats, a strain selected and maintained at the Institut d'hygiène alimentaire. Their diet was well defined and their state of health monitored. Female animals with mean weight of 200 g were used in this study. Doses of 20, 30 and 50 mg/kg were administered via the gastrointestinal route. In this experimentation, performed on 12 rats plus 3 controls, the dose considered to be sublethal was 30 mg/kg administered by gavage. These animals were sacrificed after 24 h, 48 h, 4, 8, 15, 30 and 60 day, selecting those animals with the most severely altered state, at each time. Tubular lesions started to appear by the 24th hour; the proximal tubule was the most sensitive. Lesions of the distal tubule were observed slightly later, from the 48th hour. Lesions became more intense from the 4th day onwards and reached a maximum on the 8th day. The first signs of repair of the proximal tubule and distal tubule were observed on the 15th day, but were less marked for the proximal tubule. This repair was slow and progressive. Persistent lesions of the proximal or distal tubules were still observed after two months. The glomeruli presented several alterations, which were always only moderate. Overall, paraquat induces serious life-threatening lesions of acute tubular necrosis in the absence of adequate intensive care.

Animals↗
PubMed1993

H-ras-1 point mutations in soft tissue sarcomas.

The H-ras-1 protooncogene is activated by single base substitutions occurring in either codon 12, 13, or 61. These mutations have been described with varying frequencies in several human tumor types. Since ras oncogenes were first discovered as the transforming sequences of Harvey and Kirsten murine sarcoma viruses (which also contain activating point mutations compared to the homologous cellular sequences), we wished to investigate the possibility that ras mutations might also occur in human sarcomas. We extracted DNA from six malignant fibrous histiocytomas (MFH), three embryonal rhabdomyosarcomas (ER), one alveolar rhabdomyosarcoma, one pleomorphic rhabdomyosarcoma, and one leiomyosarcoma. The DNA from regions flanking codons 12/13 and codon 61 was amplified by the polymerase chain reaction and sequenced with an automated DNA sequencer. As controls, we amplified and sequenced normal DNA (placenta) and DNA with known point mutations (T24 bladder carcinoma cells). We found three cases with mutations, all occurring in codon 12. One ER showed a G-to-T mutation in the second position of codon 12 (coding for valine instead of glycine). Two MFHs showed G-to-A mutations in the second position of codon 12 (coding for aspartic acid instead of glycine). Although a limited number of cases were sampled, we conclude that study of H-ras-1 mutations may be relevant to MFH and ER. Additional studies of N and K-ras mutations as well as more cases investigating H-ras will be required before we can ascertain the significance of ras mutations in the oncogenesis of human soft tissue sarcomas.

Base Sequence↗
PubMed1992

[Aspects of facial morphogenesis in the rat].

The facial morphogenesis of the rat has been observed by scanning microscopy on embryos taken every day from the 10th post-coitum day to term. Three points should be noted. Firstly the muzzle has at the beginning of the development an individuality which tends to diminish later. Secondly the vibrissae, whose primary elements are grouped in plates, are of great importance in the development of the muzzle. Finally, the opening between the internal parts of the nasal ridges is elevated with at the top a sharp angle, contrary to that of man which is little elevated and is arched. This could express the difference relating in each of the two cases the mesenchymatous naso-dorsal center, to which divergence between the two types of face, one with muzzle and the other without, would be linked. The primates presenting these two types, the tendency at the moment is to classify them using this discrimination. The study of the two corresponding aspects would supply a precious addition to these observations.

Animals↗
PubMed1992

Scanning electron microscopy of femoral ossification in the human foetus.

The ossification of human femoral bone was studied in 10 fetuses aged from 8 to 40 weeks, and in a 3 1/2 month-old child. After dissection and radiographic examination, each femur was sectioned in a sagittal plane. One part was processed for routine histology, the remaining one for scanning electron microscopy. By comparing the radiographic, light microscopic and scanning electron microscopic pictures, it is possible to precise the pattern of ossification and to define 3 main periods during human fetal development (pure cartilage, metaphyseal and diaphyseal ossification, constitution of a cortex and a medulla in the diaphysis).

Embryonic and Fetal Development↗
PubMed1991

[Quantification of the diameter of muscular fibres in the course of the development of the quadriceps].

Muscle biopsies were taken from the medium portion of the vastus lateralis of a hundred fetuses (aged between 10 and 40 weeks), children, adolescents and adults without any neuro-muscular disease. Diameters of the muscle fibers were measured with a Leitz ASM 68K on frozen sections which had been stained for myofibrillar ATPase. The results have been expressed as average diameters and histograms. The results demonstrated a gradual increase in diameter of the fibers during fetal development. At the birth, the average diameter of the type I and II fibers is 10-15 microns. Growth continues during postnatal development up until puberty, when the fibers reach their final diameter of 60-65 microns. Analysis of the histograms shows that before 18 weeks of gestation, there is a large dispersion in the diameter of the fibers. The first type I fibers are larger than the others and correspond to Wohlfart type b fibers. This is followed by the appearance of a second population of smaller type I fibers. These fibers gradually increase in diameter and one observes a homogenous population of type I fibers at the birth.

Adolescent↗
PubMed1987

[Ambulatory anesthesia and induced abortion. Comparative study of propofol-alfentanyl and ketamine-midazolam combinations].

The use of propofol alone or with alfentanil in the day-case anaesthesia for abortion was compared with that of ketamine with midazolam. Two hundred young women were assigned to two successive series of two groups each. The four groups were: group 1 (2 mg . kg-1 propofol only); group II (0.5 mg . kg-1 ketamine with 0.25 mg . kg-1 midazolam); group III (2 mg . kg-1 propofol with 4 micrograms . kg-1 alfentanil); group IV (1 mg . kg-1 ketamine with 0.1 mg . kg-1 midazolam). All the patients were premedicated one hour before anaesthesia with 0.25 mg . kg-1 midazolam orally. All the patients were asleep at the end of the propofol injection (60 s), and 10 to 15 s later for the ketamine-midazolam groups. The haemodynamic parameters did not vary much during induction with ketamine-midazolam. In the propofol groups, the heart rate remained steady, with an 8 to 12% fall in blood pressure. A fall of the mandible was seen in 40 and 84% of the patients in the propofol groups, with a short apnoea in 32 and 48% of these same patients. Clinical recovery was very quick, less than 12 min for all groups. The four psychomotor and sensory tests were carried out at the 30th min by 95% of the patients in the propofol groups, whereas only 50% of those in the ketamine-midazolam groups did so. Speed and quality were significantly better in the propofol groups. The most frequent adverse effect of propofol was pain during injection in 32 and 14% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Induced↗
PubMed1987

Scanning electron microscopy of human prenatal muscle development.

A scanning electron microscopic study of the development of the human quadriceps was performed in 30 fetuses ranging from 6 to 40 weeks gestation. The results clearly illustrate the hyperplastic phase of myogenesis, showing the differentiation, multiplication and fusion of the myoblasts and the subsequent formation of different generations of myotubes. The myoblasts decrease relatively in number within the developing quadriceps until the 19th week of gestation, and remain afterwards as quiescent satellite cells. The maturation of the myotubes to myofibers and the metabolic differentiation of the fibers are not accompanied by significant changes in their external form in terms of scanning electron microscopy. The hypertrophic phase of myogenesis and general fetal growth can be followed with scanning electron microscopy by the increase in size of the fibers or bundles of fibers, as well as by the differentiation of the connective tissue components of the muscle.

Embryonic and Fetal Development↗