人类小腿肌肉对运动训练生理响应的电学特性研究

目的 运动训练已被证明能够改善许多慢性肌肉功能疾病,被用于治疗衰老型肌萎缩。本文采用电阻抗成像(electrical impedance tomography,EIT)研究人类小腿肌肉对运动训练生理响应的电学特性,旨在使用EIT方法可视化运动训练对人类小腿响应肌肉隔室内肌肉纤维体积增加的效果。方法 实验对象被要求在连续5个实验日进行左、右腿单侧提踵训练,应用EIT检测每日运动训练前和运动训练后小腿肌肉的电导率分布。为了定量分析运动训练对响应肌肉隔室的作用,使用配对样本t检验分析EIT重建图像的空间平均电导率<σ>。结果 运动训练后,由小腿腓肠肌组成的M₁肌肉隔室空间平均电导率<σ>_M1显著增加。此外,连续5个实验日的EIT测量结果显示,运动训练前的空间平均电导率<σ^pre>_M1呈上升趋势。所有实验对象在实验日1早晨进行实验前的腿部瘦体重与<σ>_M1呈线性关系,即<σ>_M1随腿部瘦体重增加而增加;运...     

Calpastatin domain L is a partial agonist of the calmodulin-binding site for channel activation in Cav1.2 Ca2+ channels

Cav1.2 Ca(2+) channel activity diminishes in inside-out patches (run-down). Previously, we have found that with ATP, calpastatin domain L (CSL) and calmodulin (CaM) recover channel activity from the run-down in guinea pig cardiac myocytes. Because the potency of the CSL repriming effect was smaller than that of CaM, we hypothesized that CSL might act as a partial agonist of CaM in the channel-repriming effect. To examine this hypothesis, we investigated the effect of the competitions between CSL and CaM on channel activity and on binding in the channel. We found that CSL suppressed the channel-activating effect of CaM in a reversible and concentration-dependent manner. The channel-inactivating effect of CaM seen at high concentrations of CaM, however, did not seem to be affected by CSL. In the GST pull-down assay, CSL suppressed binding of CaM to GST fusion peptides derived from C-terminal regions in a competitive manner. The inhibition of CaM binding by CSL was observed with the IQ peptide but not the PreIQ peptide, which is the CaM-binding domain in the C terminus. The results are consistent with the hypothesis that CSL competes with CaM as a partial agonist for the site in the IQ domain in the C-terminal region of the Cav1.2 channel, which may be involved in activation of the channel.     

Assessing the role of IKCa channels in generating the sAHP of CA1 hippocampal pyramidal cells

Our previous work reported that KCa3.1 (IKCa) channels are expressed in CA1 hippocampal pyramidal cells and contribute to the slow afterhyperpolarization that regulates spike accommodation in these cells. The current report presents data from single cell RT-PCR that further reveals mRNA in CA1 cells that corresponds to the sequence of an IKCa channel from transmembrane segments 5 through 6 including the pore region, revealing the established binding sites for 4 different IKCa channel blockers. A comparison of methods to internally apply the IKCa channel blocker TRAM-34 shows that including the drug in an electrode from the onset of an experiment is unviable given the speed of drug action upon gaining access for whole-cell recordings. Together the data firmly establish IKCa channel expression in CA1 neurons and clarify methodological requirements to obtain a block of IKCa channel activity through internal application of TRAM-34.     

Evaluation of immunostimulatory effect of the arrowroot (<Emphasis Type="Italic">Maranta arundinacea</Emphasis>. L) in vitro and in vivo

Arrowroot (Maranta arundinacea. L) is an underutilized local crop potentially to be developed as carbohydrate source and functional food in Indonesia. The objectives of this research are to evaluate the immunostimulatory effects of arrowroot extracts in vitro by using animal cell culture techniques, and in vivo by using BALB/c mice. The arrowroot tuber extracts were prepared by heat-treatment at 121 °C for 20 min in distilled water. The IgM production stimulatory activity of arrowroot tuber extracts against human hybridoma HB4C5 cells and mouse splenocytes was assessed. The result indicated that the arrowroot tuber extract stimulated IgM production by HB4C5 cells and immunoglobulin (IgG, IgA and IgM) production by splenocytes in vitro. In addition, the arrowroot tuber extracts strongly enhanced interferon γ production by splenocytes. In vivo study indicated that the diet containing arrowroot extracts increased the serum IgG, IgA and IgM levels in mice. These results revealed that the arrowroot tuber extracts have immunostimulatory effects in vivo as well as in vitro.     

Both N- and C-lobes of calmodulin are required for Ca-dependent regulations of CaV1.2 Ca channels

We investigated the concentration- and Ca²⁺-dependent effects of CaM mutants, CaM₁₂ and CaM₃₄, in which Ca²⁺-binding to its N- and C-lobes was eliminated, respectively, on the Ca_V1.2 Ca²⁺ channel by inside-out patch clamp in guinea-pig cardiomyocytes. Both CaM₁₂ and CaM₃₄ (0.7-10 μM) applied with 3 mM ATP produced channel activity after “rundown”. Concentration-response curves were bell-shaped, similar to that for wild-type CaM. However, there was no obvious leftward shift of the curves by increasing [Ca²⁺], suggesting that both functional lobes of CaM were necessary for the Ca²⁺-dependent shift. However, channel activity induced by the CaM mutants showed Ca²⁺-dependent decrease, implying a Ca²⁺ sensor existing besides CaM. These results suggest that both N- and C-lobes of CaM are required for the Ca²⁺-dependent regulations of Ca_V1.2 Ca²⁺ channels.     

Cryopreservation of African violet (Saintpaulia ionantha Wendl.) shoot tips

Summary Cryopreservation of African violet via encapsulation-dehydration, vitrification, and encapsulation-vitrification of shoot tips was evaluated. Encapsulation-dehydration, pretreatment of shoot tips with 0.3 M sucrose for 2 d followed by air dehydration for 2 and 4 h resulted in complete survival and 75% regrowth, respectively. Dehydration of encapsulated shoot tips with silica gel for 1 h resulted in 80% survival but only 30% regrowth. Higher viability of shoot tips was obtained when using a step-wise dehydration of the material rather than direct exposure to 100% plant vitrification solution (PVS2). Complete survival and 90% regrowth were achieved with a four-step dehydration with PVS2 at 25°C for 20 min prior to freezing. The use of 2M glycerol plus 0.4M sucrose or 10% dimethyl sulfoxide (DMSO) plus 0.5M sucrose as a cryoprotectant resulted in 55% survival of shoots. The greatest survival (80–100%) and regrowth (80%) was obtained when shoot tips were cryoprotected with 10% DMSO plus 0.5M sucrose or 5% DMSO plus 0.75M sucrose followed by dehydration with 100% PVS2. Shoot tips cryoprotected with 2M glycerol plus 0.4M sucrose for 20 min exhibited complete survival (100%) and the highest regrowth (55%). In encapsulation-vitrification, dehydration of encapsulated and cryoprotected shoot tips with 100% PVS2 at 25°C for 5 min resulted in 85% survival and 80% regrowth.     

Protective humoral immunity induced by surface-associated material from Actinobacillus actinomycetemcomitans in mice

The aim of the present study was to determine the role of antibodies specific to anti-surface-associated material from Actinobacillus actinomycetemcomitans (anti-SAM-Aa) in an infection induced by this periodontopathogen in mice. When SAM-Aa obtained by saline extraction of A. actinomycetemcomitans Y4 was separated on one-dimensional gel electrophoresis, this constituent contained antigen fragments with molecular weights ranging from 14000 to 79000. Immunoblot analysis revealed that increased antigen dose/immunization resulted in increased numbers of antigen epitopes recognized by serum antibodies of the immunized mice. Rapid healing of the primary lesions and high levels of specific IgG antibodies after challenge with live A. actinomycetemcomitans were seen in the immunized mice, especially at the highest-dose level of 100 microg/immunization. Transfer of SAM-Aa-immunized, but not the SAM-Aa-immunized and adsorbed, serum prior to challenge with live bacteria led to rapid healing of the lesions in the recipient mice. Increased phagocytosis of A. actinomycetemcomitans by murine macrophages (RAW264.7 cells) was observed when this periodontopathogen was opsonized by the SAM-Aa-immunized, but not SAM-Aa-immunized and adsorbed, serum. These results suggest that in mice, SAM-Aa antigens may induce protective antibodies by acting, at least, as an opsonin against challenge with live A. actinomycetemcomitans.     

Hepatitis E virus infection in two different regions of Indonesia with identification of swine HEV genotype 3

Hepatitis E is an emerging disease with a high incidence globally. Few data are available on hepatitis E virus (HEV) infection in Indonesia. To obtain molecular information on HEV infection in two regions of Indonesia with different customs and swine breeding conditions, serum samples from 137 swine farm workers, 100 blood donors and 100 swine (27 fecal samples also obtained) in Yogyakarta (Central Java) and from 12 and 64 swine farm workers, 42 and 135 local residents and 89 and 119 swine in Tulungagung (East Java) and Mengwi (Bali), respectively, from our previous study, were compared. Serological tests for anti‐HEV antibodies by ELISA, HEV‐RNA detection by RT‐PCR and phylogenetic analysis were performed. The total prevalence of anti‐HEV antibodies in humans was higher in Bali (11.6%) than in Java (5.1%; P = 0.015). No significant differences in anti‐HEV prevalence among swine farm workers and local residents in Java were found. The finding of swine HEV genotype 3 in specimens from Yogyakarta and genotype 4 from Tulungagung and Bali is somewhat different from other reports. We suggest other factors in addition to close contact with swine might play an important role in HEV transmission of non‐endemic/related custom groups. To the best of our knowledge, this is the first report on swine HEV genotype 3 in Indonesia.