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Biomedical subjects

F Lou

Publications and source records attributed to F Lou.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Low fever of unknown reason in patients undergoing autologous stem cell transplantation after hematopoietic reconstitution: a clinical analysis of 13 cases].

OBJECTIVE: To investigate the reason of low fever in patients undergoing autologous stem cell transplantation after hematopoietic reconstitution. METHODS: The reasons for low fever in 13 patients undergoing autologous stem cell transplantation after hematopoietic reconstitution were comprehensively analyzed. RESULTS: After analysis of clinical features, laboratory tests, imaging and microbiological data, no reason was found for the low fever. There was no effect on the fever with anti-microbial therapy. However the low fever was controlled by low dose prednisone 5-10 mg/d or dexamethasone 2-4 mg. CONCLUSION: The reason for the low fever is not clear; it is probably nonspecific low fever induced by high-dose radiotherapy or high-dose chemotherapy.

Adolescent↗
PubMed1999

[The clinical significance of lung resistance-related protein gene (lrp), multidrug resistance-associated protein gene (mrp) and mdr-1/p170 expression in acute leukemia].

OBJECTIVE: To evaluate the relationship between lrp, mrp, mdr-1/p170 and multidrug resistance in acute leukemia (AL). METHODS: 85 AL patients were divided into three groups: untreated (A), complete remission (B) and relapsed/refractory (C). The expression of lrp, mrp and mdr-1 mRNA was detected with RT-PCR assay and that of p170 measured with immunocytochemistry. RESULTS: The frequency of lrp gene expression in ANLL A, B and C group was 11.11%, 9.09% and 36.36%, in ALL A, B, C group it was 0%, 20.00% and 46.67%; the frequency of mrp gene expression in ANLL A, B, C group was 44.44%, 9.09% and 59.09%, in ALL A, B, C group it was 28.57%, 20.00% and 53. 33%; the frequency of mdr-1 gene expression in ANLL A, B, C group was 0%, 4.54% and 59.09%, in ALL A, B, C group it was 0%, 0% and 33.33%; p170 expression in ANLL C group was (9.45 +/- 14.66) %, it was the highest value in the three groups; statistics showed that there was no correlationship among the expressions of lrp, mrp and mdr-1 gene, P > 0.05; patients with lrp and mdr-1 expression had a lower complete remission (CR) percentage than those who had not in the untreated group; the combination of lrp, mrp and mdr-1 gene detection turned out to be a more sensitive, specific and accurate way in evaluation of multidrug resistance (MDR). CONCLUSION: Overexpression of one or more genes of lrp, mrp and mdr-1/p170 is associated with MDR in AL. Expression of lrp, mrp and mdr-1/p170 is good indicators in clinical MDR. Two or three factors of lrp, mrp and mdr-1 are more valuable in the evaluation of MDR than any one of these three factors. The mechanisms of mrp, lrp and mdr-1 causing MDR are different, it means that the mechanisms of MDR are complicated the combination of lrp, mrp and mdr-1/p170 detection may be the best way to evaluate MDR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Contraction with shortening during stimulation or during relaxation: how do the energetic costs compare?

White muscle fibres from dogfish were used to compare the energetic costs of shortening by fully active muscle and by relaxing muscle. The muscle preparation was tetanized for 0.6 s and shortened either during stimulation or during relaxation. The distance shortened was 1 mm (about 15% L0, the muscle length optimum for force) and the velocity was 3.5 or 7.0 mm s-1 (about 15 or 30% V0, the maximum velocity of shortening). Isometric tetani at L0 were also investigated. Mechanical work and heat production were measured, and work + heat was taken as a measure of energetic cost. Both work and the energetic cost were higher with shortening during stimulation than with shortening during relaxation. The results suggest that shortening during relaxation, which is known to occur during locomotion in vivo, may be an energy-saving strategy.

Adenosine Triphosphatases↗
PubMed1998

Distinguishing metabolic heat from condensation heat during muscle recovery.

When a thermopile is used to measure the heat production of isolated muscle, the muscle is surrounded by gas saturated with water vapour, initially in equilibrium with the muscle. After contraction, the osmolarity of the muscle is raised so that it is no longer in equilibrium with the gas around it, and condensation will occur. When artificial muscles of known osmolarity were placed on a thermopile surrounded by gas in equilibrium with a solution of lower osmolarity, their temperature was found to be raised (by 102.7 mK osmol-1 l). This temperature increase was greatly reduced by covering the artificial muscle with a Teflon film. Experiments on living muscle from the dogfish Scyliorhinus canicula showed that muscle temperature was higher 2 min after a series of 20 twitches at 3 Hz if the muscle was not covered by Teflon than if it was covered. The Teflon covering did not diminish the muscle's contractile performance. We conclude that the condensation of water does contribute to the heat measured during the recovery period, but that when the muscle is covered by Teflon film condensation heat can largely be prevented so that only genuine metabolic recovery heat is produced.

Animals↗
PubMed1998

[Auditory P300 in assessing cognitive dysfunctions of Alzheimer's disease and schizophrenia].

OBJECTIVE: To investigate the value of auditory P300 in assessing cognitive dysfunctions of aged patients with Alzheimer's disease(AD) or schizophrenia. METHODS: An'oddball' paradigm was used to elicit the auditory P300 from 39 patients diagnosed as having Alzheimer's disease according to DSM-III-R, 34 aged schizophrenics and 40 normally age-matched subjects, by using a Dantec Concerto SEEG-16 instrument. RESULTS: The variability of P300 waveform increased in AD patients, who presented reduced N1 latency elicited by frequent stimuli. The P3 amplitude of the AD patients was lowered by 14% compared with that of schizophrenics, and by 60% than compared with that of normal controls. Compared with the normal controls, schizophrenics presented reduced N1, P2, N2 and P3 latencies, and their P3 amplitude was decreased by 54%. CONCLUSION: The auditory P300 is of value in assessing the cognitive dysfunctions of AD patients and aged schizophrenics.

Aged↗
PubMed1998

[Expression of p16 gene in malignant lymphoma detected by immunohistochemical and in situ hybridization techniques].

OBJECTIVE: To investigate the expression of p16 gene in non-Hodgkin's lymphoma (NHL) and its clinicopathological significance. METHODS: Paraffin embedded biopsies from 64 patients with NHL were analysed for p16 gene expression by immunohistochemical methods and in situ hybridization technique. RESULTS: Of the 64 NHL cases, 34(53.1%) were positive for p16 protein, 30(46.9%) lacked p16 protein, most of the positive signals were seen in the nuclei; 45(70.3%) were p16 mRNA positive, 19(29.7%) lost p16 mRNA and p16 mRNA was clearly observed in the cytoplasm of lymphocytes. p16 expression did not show correlation with such factors as sex, age and immunophenotype in NHL, but there was a significant difference between the pattern of expression of p16 in well differentiated lymphomas and poorly differentiated lymphomas (P < 0.05). Moreover, 42 patients were followed postoperatively for over 3 years, both p16 protein and mRNA correlated with the prognosis of these patients. CONCLUSION: There was a higher incidence of negative expression of p16 mRNA and protein in NHL, which indicates that p16 gene inactivation may play an important role in the genesis and development of some NHL. The frequency of negative expression of p16 mRNA was lower than that of p16 protein suggests that it may be due to post-transcriptional regulation or the unsteadiness of mRNA or protein expressed. The positive expression of both p16 mRNA and p16 protein may be features for favorable prognosis in patients with NHL.

Adolescent↗
PubMed1998

Shortening during stimulation vs. during relaxation. How do the costs compare?

White muscle fibres from dogfish were used to investigate the energetic cost of shortening by fully active muscle and by relaxing muscle. The muscle preparation was tetanized for 0.6 s and shortened by 1 mm (about 15% L0) at 7 mm/s (about 30% V0) either during stimulation or during relaxation. Isometric tetani at L0 were also investigated. Mechanical work was calculated from force and length change. Work + heat was taken as a measure of energetic cost. Both work and energetic cost were higher for shortening during stimulation than during relaxation. We also evaluated separately the work and heat associated with the contractile component and with the series elastic component. Work stored in the series elasticity could be completely recovered as external work when the shortening occurred during relaxation.

Animals↗
PubMed1997

The energetic cost of activation of white muscle fibres from the dogfish Scyliorhinus canicula

The energetic cost of activation was measured during an isometric tetanus of white muscle fibres from the dogfish Scyliorhinus canicula. The total heat production by the fibres was taken as a measure of the total energetic cost. This energy consists of two parts. One is due to crossbridge interaction which produces isometric force, and this part varies linearly with the degree of filament overlap in the fibres. The other part of the energy is that associated with activation of the crossbridges by Ca2+, mainly with uptake of Ca2+ into the sarcoplasmic reticulum by the ATP-driven Ca2+ pump. Total heat production was measured at various degrees of filament overlap beyond the optimum for force development. Extrapolation of heat versus force production data to evaluate the heat remaining at zero force gave a value of 34&plusmn;5 % (mean &plusmn; s.e.m., N=24) for activation heat as a percentage of total heat production in a 2.0 s isometric tetanus. Values for 0.4 and 1.0 s of stimulation were similar. Comparison with values in the literature shows that the energetic cost of activation in dogfish muscle is very similar to that of frog skeletal muscle and it cannot explain the lower maximum efficiency of dogfish muscle compared with frog muscle. The proportion of energy for activation (Ca2+ turnover) is similar to that expected from a simple model in which Ca2+ turnover was varied to minimize the total energy cost for a contraction plus relaxation cycle.

Journal Article↗
PubMed1996

Interaction between yeast Cdc6 protein and B-type cyclin/Cdc28 kinases.

During purification of recombinant Cdc6 expressed in yeast, we found that Cdc6 interacts with the critical cell cycle, cyclin-dependent protein kinase Cdc28. Cdc6 and Cdc28 can be coimmunoprecipitated from extracts, Cdc6 is retained on the Cdc28-binding matrix p13-agarose, and Cdc28 is retained on an affinity column charged with bacterially produced Cdc6. Cdc6, which is a phosphoprotein in vivo, contains five Cdc28 consensus sites and is a substrate of the Cdc28 kinase in vitro. Cdc6 also inhibits Cdc28 histone H1 kinase activity. Strikingly, Cdc6 interacts preferentially with B-type cyclin/Cdc28 complexes and not Cln/Cdc28 in log-phase cells. However, Cdc6 does not associate with Cdc28 when cells are blocked at the restrictive temperature in a cdc34 mutant, a point in the cell cycle when the B-type cyclin/Cdc28 inhibitor p40Sic1 accumulates and purified p40Sic1 inhibits the Cdc6/Cdc28 interaction. Deletion of the Cdc28 interaction domain from Cdc6 yields a protein that cannot support growth. However, when overproduced, the mutant protein can support growth. Furthermore, whereas overproduction of wild-type Cdc6 leads to growth inhibition and bud hyperpolarization, overproduction of the mutant protein supports growth at normal rates with normal morphology. Thus, the interaction may have a role in the essential function of Cdc6 in initiation and in restraining mitosis until replication is complete.

CDC28 Protein Kinase, S cerevisiae↗
PubMed1996

The relationship between the intracellular Ca2+ transient and the isometric twitch force in frog muscle fibres.

The calcium-sensitive fluorescent indicator fluo-3 was used to monitor the intracellular free calcium concentration ([Ca2+]i) during isometric twitches in twenty-nine single muscle fibres from the anterior tibialis muscle of Rana temporaria (sarcomere length, 2.2 microns; 2-4 degrees C). The transient change in [Ca2+]i in response to a single stimulus was very brief. The time to peak and the duration of the Ca2+ signal, measured at 50% of the peak amplitude, were 8.3 +/- 0.2 and 22.1 +/- 1.4 ms (mean +/- S.E.M., n = 29), respectively. The mean peak amplitude of the Ca2+ transient was 3.2 +/- 0.1 microM, ranging from 2.46 to 3.92 microM among the different fibres. The isometric force started to rise 2.5 ms before [Ca2+]i reached its maximum value. When peak twitch force was attained, [Ca2+]i had already declined to approximately 10% of its maximum value. The peak force produced during a twitch was closely related to the decay phase of the Ca2+ transient, a slower decay of [Ca2+]i being associated with a greater amplitude of the twitch. The amplitude and duration of the Ca2+ transient varied in a systematic way relative to one another in different fibres, in that a greater amplitude was associated with a more rapid decay of the Ca2+ transient. NO3- and Zn2+ added to the external medium greatly enhanced the peak twitch force without markedly affecting the amplitude of the Ca2+ transient. However, both agents delayed the decay of [Ca2+]i. It is concluded that the decay phase of the Ca2+ transient is a more important determinant of the mechanical response during an isometric twitch than is the peak amplitude of the transient.

Aniline Compounds↗
PubMed1995

The effects of 2,3-butanedione monoxime (BDM) on the force-velocity relation in single muscle fibres of the frog.

The effects of 2,3-butanedione monoxime (BDM) on the force-velocity relation were studied in single fibres from the anterior tibialis muscle of Rana temporaria (2.2 microns sarcomere length, temperature 1.9-2.4 degrees C). BDM (1.0 and 1.8 mM) suppressed the maximum tetanic force (P0) and the maximum speed of shortening (Vmax), and increased the main curvature of the force-velocity relation. The biphasic shape of the force-velocity curve was maintained well in the presence of BDM, but the interrelation between the two portions of the force-velocity relation was significantly changed. Caffeine (0.5 mM) added in the presence of BDM increased the initial rate of rise of force during twitch and tetanus, increased the twitch amplitude, but did not affect the maximum tetanic force. The latter finding suggests that the contractile system was fully activated during tetanus in the presence of BDM. The results support the view that BDM affects the cross-bridge function by exerting a direct action upon the contractile apparatus. The decrease in tetanic force and the change of the force-velocity relation induced by BDM may be interpreted to show that a larger fraction of the attached cross-bridges is in a state of low force production under the influence of BDM. This view is further supported by the observation that the instantaneous stiffness of the muscle fibre is reduced proportionally less by BDM than the tetanic force.

Animals↗
PubMed1995

[Effect of acupuncturing houxi and shenmen in treating cerebral traumatic dementia].

UNLABELLED: Sixty-two cerebral traumatic dementia patients were randomly divided into two groups: acupuncture group (32 cases) and physiotherapy group (30 cases). The changes of mini-mental status examination (MMSE) scores and auditory evoked potential P300 were observed before and after treatment. RESULTS: marked effective rate and effective rate of acupuncture group were 46.9% and 81.3% respectively, significantly higher than 10.0% and 30.0% of physiotherapy group (P < 0.01). It was found that after treatment the above-mentioned indexes in acupuncture group changed significantly (P < 0.05 - 0.001), while in physiotherapy group were not (P > 0.05). The therapeutic effect in acupuncture group was better than that in physiotherapy group (P < 0.001). The results confirmed that the cognitive function of cerebral traumatic dementia patients was enhanced effectively with acupuncturing at Houxi and Shemen.

Acupuncture Points↗
PubMed1995

[A clinical study on multidrug resistance gene (MDR1) expression in acute leukemia].

The authors established a highly sensitive, specific and quantitative method-RT-PCR for measuring the levels of MDR1 mRNA in 91 acute leukemic samples (including 30 untreated cases, 32 remission cases, 29 refractory and relapse cases). The results showed that MDR1 mRNA positive rate for refractory and relapse cases, untreated cases and remission cases were 82.8%, 40.0%, 28.1% respectively. In untreated patients, it was found that the first complete remission rate differed significantly between MDR1 positive (41.7%) and MDR1 negative groups (88.9%) (P < 0.05). In remission group, MDR1 positive cases had a higher relapse rate than MDR1 negative case (66.7%; 13.0% P < 0.01) and all these cases relapsed of MDR1 gene overexpression (6 cases) were resistant to further treatment. It is concluded that the expression of MDR1 mRNA might be an unfavorable prognostic factor for patients with acute leukaemia and could predict the efficacy of intensive chemotherapy and serve as a high risk factor for early and resistant relapse.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Variation in myoplasmic Ca2+ concentration during contraction and relaxation studied by the indicator fluo-3 in frog muscle fibres.

1. The fluorescent dye fluo-3, in its permeant acetoxymethyl form, was used to monitor calcium transients during twitch and tetanus of single fibres isolated from the anterior tibialis muscle of Rana temporaria (2-5 degrees C). 2. Fluo-3 was loaded into the muscle fibre by diffusion. Under the experimental conditions used, approximately 45% of maximal fluorescence was reached during a 1 s fused isometric tetanus. Fluo-3 had no detectable effect on the mechanical response of the fibre. 3. The free calcium concentration in the myoplasm, [Ca2+]i, and its variation with time, was calculated from the fluorescence signal by accounting for the on- and off-rate constants for the binding of calcium to the dye. The time course of the calcium transient during twitch and tetanus determined in this way agreed well with previous measurements based on fast-reacting calcium-sensitive dyes. 4. [Ca2+]i declined steeply during the initial phase of force relaxation in both twitch and tetanus, but exhibited a secondary rise that closely coincided with the pseudoexponential fall of tension after the shoulder in the tetanus myogram. The rate of decay of [Ca2+]i during relaxation and the rate of decline of force both became progressively reduced by repetitive stimulation. 5. Stretch and shortening ramps performed during the plateau of an isometric tetanus had no detectable effect upon the calcium transient during the movement. By contrast, shortening and stretch imposed during the linear phase of relaxation both led to an increase of [Ca2+]i and to a steepening of the relaxation phase. 6. The results strongly suggest that the non-uniform length changes that are known to occur along a muscle fibre during relaxation enhance the release of calcium from the contractile system. The calcium mobilized in this way probably accounts for the transitory increase of [Ca2+]i that is observed during the latter part of force relaxation.

Aniline Compounds↗
PubMed1994

Moderate fatigue studied at great sarcomere lengths in frog single muscle fibres.

Single fibres from the anterior tibialis muscle of Rana temporaria (temperature, 2-3 degrees C) were moderately fatigued at a prestretched sarcomere length (approximately 3.6 microns) by reducing the intervals between 2 s tetani from 240 to 20 s. Changes in length of marked segments along the muscle fibre were monitored during fixed-end tetani using a photoelectric recording system. In contrast to the situation at 2.2 microns sarcomere length, the central region of the fibre was elongated during tetanus at the prestretched fibre length, whereas the segments next to the fibre-tendon junctions (end segments) shortened correspondingly. These length changes were associated with a slow climb of force (tension creep). During development of fatigue, the maximum tetanic tension was reduced to about 78% of the control value and the time course of the tetanus was markedly changed. The tension creep observed in control tetanus was greatly reduced during fatigue, the tetanic tension remaining nearly constant after an initial rising phase. The change in shape of the force myogram during fatigue was associated with a considerable reduction in the amplitude of segment movements along the fibre. The results are explainable by assuming that the end segments (having shorter sarcomeres) become more fatigued than other parts in series along the fibre. At the same time the central segments are likely to have acquired a higher ability to resist stretch by the end segments.

Animals↗
PubMed1993

The high-force region of the force-velocity relation in frog skinned muscle fibres.

The force-velocity relation has been studied during calcium-induced contracture of chemically skinned fibres from the semitendinosus muscle of Rana temporaria with special interest focused on the high-load region. The force-velocity curve was hyperbolic at low and intermediate loads but departed below the hyperbola as the load exceeded about 80% of the isometric force (P0). The force intercept (P*0) of the hyperbola derived from force-velocity data truncated at 0.78 P0 was higher than P0 (P*0/P0 = 1.14 +/- 0.04). At submaximum Ca2+ concentration, where the isometric force of the fibre was 65-75% of the maximum value, the force-velocity data still departed below the hyperbola at high loads (P*0/P0 = 1.09 +/- 0.04). The departure of the force-velocity data from the hyperbola at high force was also found at high ionic strength (250 mM), but not at low ionic strength (150 mM) (P*0/P0 = 1.09 +/- 0.03 and 0.98 +/- 0.03, respectively). The force-velocity relations derived under different experimental conditions could be fitted well by a modified version of Hill's (1938) hyperbolic equation (Edman 1988) using similar numerical values of k1 and k2 in the latter equation. The results indicate that the force-velocity relation in skinned muscle fibres is biphasic, and that the two curvatures, as in intact muscle fibres, are closely related to one another. Furthermore the evidence supports the hypothesis that the altered shape of the force-velocity relation at high loads is not related to the force level per se but rather to the speed of shortening of the contractile system (Edman 1992).

Animals↗