Excessive daytime sleepiness and alcohol consumption among commercial drivers.

BACKGROUND: Commercial drivers suffering from excessive daytime sleepiness (EDS) have been identified as a major cause of road traffic accidents. Alcohol usage directly affects sleep, adversely affecting next-day alertness and performance. AIMS: To examine the relationship between alcohol consumption and EDS among commercial truck drivers in Japan and the implications of this on public health. METHODS: All participants in this cross-sectional study were commercial motor vehicle drivers from Tokyo and Niigata Prefecture. Participants completed a self-administered questionnaire with details of their age, body mass index, alcohol consumption, Epworth Sleepiness Scale (ESS) score and tobacco usage. Participants' oxygen desaturation index was determined by a pulse oximetry device that participants took home. RESULTS: A total of 1422 males registered with the Japan Trucking Association and aged 20-69 years participated. The multivariate-adjusted odds ratio (OR) of EDS among participants aged <43 years was 0.81 (95% confidence interval (CI) 0.47-1.40) for light drinkers, 0.93 (95% CI 0.51-1.70) for moderate drinkers and 0.61 (95% CI 0.21-1.79) for heavy drinkers, compared to non-drinkers. The multivariate-adjusted OR among participants aged ≥43 years was 1.42 (95% CI 0.59-3.45) for light drinkers, 1.53 (95% CI 0.63-3.75) for moderate drinkers and 3.37 (95% CI 1.14-9.96) for heavy drinkers (P for interaction = 0.05). CONCLUSION: We found that the association between ESS and alcohol intake was more evident among those aged ≥43 years, who reported higher levels of EDS with increased alcohol consumption.

Association of salivary lactate dehydrogenase level with systemic inflammation in a Japanese population.

BACKGROUND AND OBJECTIVE: Salivary lactate dehydrogenase (LDH) was reported to be a useful parameter for the screening of periodontal disease. We performed a cross-sectional study to verify the usefulness of salivary LDH as a biomarker of periodontitis and to investigate the association of severity of periodontitis with systemic inflammation by measuring salivary LDH and serum high sensitive C-reactive protein (hs-CRP) levels in a community-based middle-aged and elderly population in Japan. MATERIAL AND METHODS: We recruited 644 men and 1171 women, aged 30-79 years, who participated in the Toon Health Study during 2011-15. Periodontal condition was assessed by full-mouth examination including mean value of probing depth, percentage of probing depth of ≥4 mm and ≥6 mm, and bleeding on probing. Saliva and blood serum samples were collected for measurement of salivary LDH level and hs-CRP, respectively. A linear trend across quartiles of salivary LDH was calculated using linear regression. Interaction of salivary LDH and overweight status (body mass index of ≥25 kg/m2 ) was tested using the cross-product term of log-transformed continuous salivary LDH and overweight status. RESULTS: Analysis of covariance adjusted for potential confounders revealed strong associations between salivary LDH level and the indicators of periodontal condition (P < .01) in both men and women. Sex- and age-adjusted mean values of hs-CRP according to salivary LDH quartiles were 0.40, 0.45, 0.45 and 0.50 mg/L (P for trend <.01). Although the association was attenuated after further adjustment for body mass index, hypertension, diabetes mellitus, dyslipidemia, alcohol intake, smoking status and physical activity. When stratified by overweight status, the association remained significant in overweight individuals (P = .03). The multivariable adjusted odds ratio of hs-CRP level of ≥1 mg/L for the highest vs lowest quartile of salivary LDH was 1.93 (95% CI, 1.01-3.69) in overweight individuals, but not significant in non-overweight individuals. CONCLUSION: Salivary LDH appears to be a promising biomarker for the mass screening of periodontitis in local community health settings. High salivary LDH levels, particularly in overweight individuals might contribute to prevention of cardiovascular disease, through measuring systemic inflammatory burdens as well as traditional cardiovascular risk factors.

Scalloped tongue is associated with nocturnal intermittent hypoxia among community-dwelling Japanese: the Toon Health Study.

Scalloped tongue is considered as a possible clinical finding of obstructive sleep apnoea (OSA). There are few evidence of the association between scalloped tongue and OSA. To examine the association between scalloped tongue and nocturnal intermittent hypoxia (NIH), a surrogate marker of OSA, among a general Japanese population. Study participants were 398 men and 732 women aged 30-79 years who participated in the Toon Health Study from 2011 to 2014. Scalloped tongue was classified into three categories: none, mild and moderate-to-severe. Moderate-to-severe NIH was defined as the 3% oxygen desaturation index of ≥15 events/h during sleep for one night with pulse oximetry. The multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for moderate-to-severe NIH were calculated according to scalloped tongue categories using a logistic regression model. There were 69 (6·1%) moderate-to-severe NIH cases in this population. The multivariable-adjusted ORs (95% CIs) of moderate-to-severe NIH were 1·59 (0·85-2·95) for mild and 2·39 (1·10-5·17) for the moderate-to-severe scalloped tongue group compared with the group without scalloped tongues. When stratified by overweight status (BMI <25 or ≥25 kg m-2 ), the respective ORs (95% CIs) were 2·83 (1·06-7·55) and 4·74 (1·28-17·49) among overweight individuals, and 0·94 (0·40-2·70) and 1·52 (0·57-4·05) among non-overweight individuals. Scalloped tongue was associated with higher prevalence of moderate-to-severe NIH among the general Japanese population and this association was more evident in overweight individuals.

Intramuscular dissociation of echogenicity in the triceps surae characterizes sporadic inclusion body myositis.

BACKGROUND AND PURPOSE: Differential diagnosis of sporadic inclusion body myositis (s-IBM) and polymyositis (PM)/dermatomyositis (DM) is difficult and can affect proper disease management. Detection of heterogeneous muscular involvement in s-IBM by muscle sonography could be a unique diagnostic feature. METHODS: Sonography of the lower leg and forearm was performed in patients with s-IBM, PM/DM and control subjects (n = 11 each). Echo intensities (EIs) of the adjacent muscles [medial head of the gastrocnemius versus soleus and the flexor digitorum profundus (FDP) versus flexor carpi ulnaris (FCU)] were scored by three blinded raters. The mean EIs of these muscles were compared using computer-assisted histogram analysis. RESULTS: Both evaluation methods showed high echoic signals in the gastrocnemius of patients with s-IBM. EIs were significantly different between the gastrocnemius and soleus in patients with s-IBM, but not in those with DM/PM and the controls. In the forearm, although the EI of the FDP was higher in the s-IBM group than in the other groups, the EI differences between the FDP and FCU did not differ significantly between disease groups. The difference in area under the curves to differentiate between s-IBM and DM/PM was greatest between the gastrocnemius-soleus EIs (0.843; P = 0.006). CONCLUSIONS: High echoic signals in the medial gastrocnemius compared with those of the soleus are suggestive of s-IBM over PM/DM.

Phase I/II trial of definitive carbon ion radiotherapy for prostate cancer: evaluation of shortening of treatment period to 3 weeks.

BACKGROUND: The purpose of this study was to evaluate the feasibility of a new shortened 3-week treatment schedule of carbon ion radiotherapy (CIRT) for prostate cancer. METHODS: Beginning in May 2010, patients with T1b-T3bN0M0, histologically proven prostate adenocarcinoma were enrolled in the phase II trial of CIRT. Patients received 51.6 GyE in 12 fractions over 3 weeks (protocol 1002). The primary end point was defined as the incidence of late adverse events that were evaluated based on the Common Terminology Criteria for Adverse Events version 4.0. Biochemical failure was determined using the Phoenix definition (nadir +2.0 ng ml(-1)). RESULTS: Forty-six patients were enrolled, and all patients were included in the analysis. The number of low-, intermediate-, and high-risk patients was 12 (26%), 9 (20%), and 25 (54%), respectively. The median follow-up period of surviving patients was 32.3 months. Two patients had intercurrent death without recurrence, and the remaining 44 patients were alive at the time of this analysis. In the analysis of late toxicities, grade 1 (G1) rectal haemorrhage was observed in 3 (7%) patients. The incidence of G1 haematuria was observed in 6 (13%) patients, and G1 urinary frequency was observed in 17 (37%) patients. No ⩾G2 late toxicities were observed. In the analysis of acute toxicities, 2 (4%) patients showed G2 urinary frequency, and no other G2 acute toxicities were observed. CONCLUSIONS: The new shortened CIRT schedule over 3 weeks was considered as feasible. The analysis of long-term outcome is warranted.

Gene delivery to periodontal tissue using Bubble liposomes and ultrasound.

BACKGROUND AND OBJECTIVE: Periodontitis is the most common inflammatory disease caused by oral biofilm infection. For efficient periodontal treatment, it is important to enhance the outcome of existing regenerative therapies. The physical action of an ultrasound may be able to deliver a therapeutic gene or drugs into the local area of the periodontium being treated for periodontal regeneration. Previously, we developed "Bubble liposomes" as a useful carrier for gene or drug delivery, and reported that delivery efficiency was increased with high-frequency ultrasound in vitro and in vivo. Hence, the aim of the present study was to examine the possibility of delivering genes into gingival tissues using Bubble liposomes and ultrasound. MATERIAL AND METHODS: We attempted to deliver naked plasmid DNA encoding luciferase or enhanced green fluorescent protein (EGFP) into the lower labial gingiva of Wistar rats using Bubble liposomes, with or without ultrasound exposure. Ultrasound parameters were optimized for intensity (0-4.0 W/cm(2) ) and exposure time (0-120 s) to establish the most efficient conditions for exposure. The efficacy and duration of gene expression in the gingiva were investigated using a luciferase assay and fluorescence microscopy. RESULTS: The strongest relative luciferase activity was observed when rats were treated under the following ultrasound conditions: 2.0 W/cm(2) intensity and 30 s of exposure time. Relative luciferase activity, 1 d after gene delivery, was significantly higher in gingiva treated using Bubble liposomes and ultrasound than in gingiva of the other treatment groups. Histological analysis also showed that distinct EGFP-expressing cells were observed in transfected gingiva when rats were treated under optimized conditions. CONCLUSION: From these results, the combination of Bubble liposomes and ultrasound provides an efficient technique for delivering plasmid DNA into the gingiva. This technique can be applied for the delivery of a variety of therapeutic molecules into target tissue, and may serve as a useful treatment strategy for periodontitis.

Preliminary development and evaluation of the support system for care of mechanically ventilated patients.

BACKGROUND: We wanted to demonstrate the feasibility of a novel computer-assisted ventilator alarm system, the support system for care of mechanically ventilated patients (SCMVP), to detect gas leaks and provide graphical information on the site of the leak in a manikin model. METHODS: We tested six leakage scenarios. Four scenarios were applied to both the respiratory circuits with the SCMVP and without the SCMVP (conventional system), and two scenarios were each specific to one of the systems. Fifteen registered nurses were asked to manage three scenarios each (two mutual and one system-specific scenario). Time to identify the site of the leak was measured and compared between the two systems. RESULTS: The SCMVP showed significantly shorter time for troubleshooting in one of the four mutual scenarios and shorter accumulated time for troubleshooting in the four mutual scenarios [18.0 (range, 14.5-19.5) and 48.5 (9.0-180.0) s, respectively] compared with the conventional system [76.0 (47.0-133.8) and 82.5 (16.0-180.0) s, respectively]. In the mutual scenarios, SCMVP resulted in significantly more frequent incidences of successful troubleshooting within 30 s and less frequent incidences of troubleshooting requiring >180 s [43.3% (13/30) and 6.7% (2/30), respectively] compared with the conventional system [13.3% (4/30) and 30% (9/30), respectively]. CONCLUSIONS: The SCMVP can facilitate rapid and successful recognition of the site of leak in a respiratory circuit in a simulation environment.

Surgical treatment of gastric cancer in Japan, trend from standardization to individualization.

Japan has a huge number of patients with gastric cancer and has developed various surgical treatments for this disease.This paper intends to introduce our strategies against gastric cancer. The Japanese Gastric Cancer Association was established in 1962. Its major purposes are promotion of basic and clinical researches and popularization of the latest knowledge and technologies. For the purposes, the association organized the annual scientific meeting and the nationwide registry by member hospitals, and published the Japanese Classification of Gastric Cancer (1) and the Treatment Guide Line (2). The nationwide registry reported that proportion of Stage-I cancer was 22.5% in 1963-66,which increased to 59.3% in 2008 (3,4,5). 11,261 patients with gastric resection were registered by 187 hospitals in 2008. 63 patients were died within 30 postoperative days and the direct death rate was 0.55%. 5 year survival rate (5YSR) was 37.5% for resected cases in 1963-66, which was improved to 70.1% in 2008. 5YSR was improved from 55.1% to 74.1% for Stage-II, and from 39.1% to 48.8% for Stage-III in the period. According to remarkable increase of early stage cancer, principle of surgical treatments was shifted from "€œextended and standardized surgery for radicality" €to "€œreasonable and individual surgery considering safety and quality of life"€. This trend produced a large variation in surgical treatments; namely 1) minimally invasive surgeries,2) function preserving surgeries, 3) optimal extent of lymph node dissection, and 4) aggressive but safe surgeries.Intention of this paper is to explain these procedures, the intentions, the indications, and the treatment results.

Dietary patterns and risk of cardiovascular deaths among middle-aged Japanese: JACC Study.

BACKGROUND AND AIMS: Little evidence showed the association between dietary patterns and cardiovascular disease among Japanese. The objective of this study was to examine whether dietary patterns are associated with cardiovascular disease among middle-aged Japanese. METHODS AND RESULTS: At baseline (1988-1990), 26,598 men and 37,439 women aged 40-79 years enrolled in the Japan Collaborative Cohort (JACC) Study. During the follow-up through 2003, 578 men and 499 women died from stroke, and 272 men and 207 women died from coronary heart disease. We identified three major dietary patterns, 'vegetable', 'animal food' and 'dairy product', by factor analysis for both sexes. The multivariable hazard ratio (HR) and 95% confidence intervals of mortality from total cardiovascular disease in the highest versus lowest quintiles of the vegetable pattern were 0.93 (0.78-1.13), p for trend=0.73 for men and 0.82 (0.67-1.00), p for trend=0.04 for women. The respective HRs of mortality from stroke in the highest versus lowest quintiles of the dairy product pattern were 0.65 (0.49-0.86), p for trend=0.01 for men and 0.70 (0.51-0.97), p for trend=0.02 for women, and those of total cardiovascular disease were 0.89 (0.74-1.08), p for trend=0.23 for men and 0.76 (0.61-0.94), p for trend=0.01 for women. The animal food pattern was not associated with mortality from stroke, coronary heart disease or total cardiovascular disease for either sex. CONCLUSION: We found that 'vegetable' and 'dairy product' patterns were associated with lower morality from cardiovascular disease, while the 'animal food' pattern was not associated with mortality from cardiovascular disease among Japanese.

Collective excitations in a melt of fast phase change material GeCu2Te3.

Inelastic x-ray scattering measurements have been carried out to investigate atomic dynamics in a melt of fast phase change material GeCu2Te3. The dynamic structure factor was analysed using the model function with three damped harmonic oscillator components. By investigating the correlation between the excitation energy and the linewidth, and that between the excitation energy and the intensity on contour maps of a relative approximate probability distribution function proportional toexp(-χ2/N), we could judge the reliability of each inelastic excitation in the dynamic structure factor. The results indicate that there are two inelastic excitation modes besides the longitudinal acoustic one in the liquid. The lower energy excitation could be assigned to the transverse acoustic one whereas the higher energy one disperses like fast sound. The latter result may imply that the liquid ternary alloy exhibits a microscopic phase separation tendency.

Synergistic effect of PKC activation and actin filament disruption on carbonate apatite-facilitated lymphocyte transfection.

Leukemia and lymphoma cells are potential targets for genetic manipulation in cancer therapy. On the other hand, genetically modified autologous lymphocytes expressing a chimeric antigen against a receptor overexpressed in tumor cells or tumor vasculature are promising cell-based therapeutics for cancer.However, the lack of a smart device for efficient transgene delivery to the lymphocytes poses the major obstacle to the successful clinical applications of these attractive approaches. Recently, we developed a carbonate apatite-based nanocarrier system for effective intracellular delivery and release of DNA molecules, achieving very high level of transgene expression in both primary and cancer cells. Although its efficacy in human T leukemia cells is relatively poor, immobilization of fibronectin and/or chimeric E-cadherin-Fc on particle surface could enhance transgene delivery in presence of an actin filament disrupter. Here, we report for the first time that simultaneous stimulation of human T leukemia cells by a protein kinase C (PKC) activator, a Ca(2+) ionophore and an actin filament disrupter dramatically accelerated carbonate apatite-mediated transgene delivery in the cells, resulting in over 100-fold more efficacy than commcercially available lipofectamine.

Outcomes of endoscopic and surgical resection for a second primary cancer in the residual cervical esophagus after thoracic esophagectomy.

Patients who have received subtotal esophagectomy for thoracic esophageal cancer must be closely monitored for second primary malignancies. The purpose of this study is to review and assess patients who developed a second primary esophageal cancer in the residual cervical esophagus. Between 1996 and 2010, 10 patients were diagnosed in our hospital with esophageal squamous cell cancer in the residual cervical esophagus after undergoing thoracic esophagectomy and were treated with endoscopic or surgical resection. Data from these patients were reviewed retrospectively. Seven of the 10 patients (70%) had multiple primary carcinoma lesions at the time of their esophagectomy. A second primary cancer in the residual cervical esophagus was detected in eight patients during follow-up endoscopic examinations while the patients were still asymptomatic. Seven of the patients underwent endoscopic resection for a superficial cancer. None of those patients experienced any complications, and all are currently alive and cancer-free. The remaining three patients underwent resection of the cervical esophagus with regional lymph node dissection. Two of those patients experienced severe complications; one subsequently died (hospital death) from pneumonia, 12 months after surgery, while the other died from recurrence of his cancer. The third patient is alive and cancer-free. Early detection of a second primary malignancy in the residual cervical esophagus followed by endoscopic resection is the best treatment strategy for patients who previously received subtotal esophagectomy for thoracic esophageal cancer. Surgical resection puts patients at high risk of mortality or morbidity.

Salivary Alpha-Amylase Activity and Mild Cognitive Impairment among Japanese Older Adults: The Toon Health Study.

BACKGROUND: There is growing interest in examining objective markers for early identification and behavioral intervention to prevent dementia and mild cognitive impairment in clinical and community settings. OBJECTIVE: To investigate the association between salivary alpha-amylase as an objective measure of psychological stress response and mild cognitive impairment for the implication of psychological stress in the development of mild cognitive impairment. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study involved 865 participants aged ≥ 65 years. A saliva sample was collected in the morning, and the levels of salivary alpha-amylase were assayed. Mild cognitive impairment was evaluated using the Japanese version of the Montreal Cognitive Assessment; a score < 26 was indicative of mild cognitive impairment. A multivariable logistic regression model was used to examine the association of salivary alpha-amylase and mild cognitive impairment after adjusting for age, sex, current drinking status, current smoking status, body mass index, hypertension, diabetes mellitus, physical activity, education, social support, social network, and heart rate variability. RESULTS: Salivary alpha-amylase was associated with mild cognitive impairment (the multivariable-adjusted odds ratio [95% confidence interval] for the 1-standard deviation increment of log-transformed salivary alpha-amylase was 1.24 [1.07-1.44]). This significant association persisted after adjusting for various confounding factors. CONCLUSION: Elevation of salivary alpha-amylase was associated with mild cognitive impairment among Japanese community-dwelling older adults. This suggests that salivary alpha-amylase is a useful objective marker of psychological stress responses associated with mild cognitive impairment.

Therapeutic strategy for the treatment of postoperative recurrence of esophageal squamous cell carcinoma: clinical efficacy of radiotherapy.

We investigated the effectiveness of chemoradiotherapy for the treatment of lymph node recurrence and hematogenous metastasis after esophagectomy for esophageal squamous cell carcinoma. Between 2001 and 2006, 216 patients with thoracic esophageal squamous cell carcinoma had curative esophagectomy. Of those, 23 with lymph node recurrence received chemoradiotherapy (50.0-68.8 Gy). In addition, five patients had isolated recurrences in a distant organ and received chemoradiotherapy (50.0-60.0 Gy). We analyzed outcomes from the radiotherapy for recurrent esophageal cancer. The 1-, 2-, and 5-year survival rates after recurrence for the 23 patients whose lymph node recurrence was treated with chemoradiotherapy were 52, 31, and 24%, respectively, and the median survival time was 13 months. Among the five patients with recurrent tumors in a distant organ, chemoradiotherapy produced a complete response in two patients, a partial response in one patient, and stable disease in two patients, giving an effectiveness rate of 60% (complete response + partial response). Chemoradiotherapy has a beneficial prognostic effect in patients with lymph node recurrence of esophageal squamous cell carcinoma. Chemoradiotherapy for a metastatic tumor in a distant organ may be the treatment of choice in cases where systemic chemotherapy has proven ineffective.

Small cell carcinoma of the esophagus treated with esophagectomy and following chemotherapy: case report with review of the literature.

We report 2 cases of small cell carcinoma of the esophagus treated with esophagectomy as a primary treatment and following chemotherapy. One patient (pT1N1M0) achieved long-term survival, while the other patient (pT1N1M1-lym) died 18 months after surgery. We used reports on 47 Japanese patients receiving esophagectomy as a primary treatment to determine when esophagectomy for small cell carcinoma of the esophagus is indicated. We conclude that esophagectomy as a local treatment provides relatively good long-term survival only in patients without lymph node involvement.

Quantification of (R)-[11C]PK11195 binding in rheumatoid arthritis.

PURPOSE: Rheumatoid arthritis (RA) involves migration of macrophages into inflamed areas. (R)-[(11)C]PK11195 binds to peripheral benzodiazepine receptors, expressed on macrophages, and may be used to quantify inflammation using positron emission tomography (PET). This study evaluated methods for the quantification of (R)-[(11)C]PK11195 binding in the knee joints of RA patients. METHODS: Data from six patients with RA were analysed. Dynamic PET scans were acquired in 3-D mode following (R)-[(11)C]PK11195 injection. During scanning arterial radioactivity concentrations were measured to determine the plasma (R)-[(11)C]PK11195 concentrations. Data were analysed using irreversible and reversible one-tissue and two-tissue compartment models and input functions with various types of metabolite correction. Model preferences according to the Akaike information criterion (AIC) and correlations between measures were evaluated. Correlations between distribution volume (V(d)) and standardized uptake values (SUV) were evaluated. RESULTS: AIC indicated optimal performance for a one-tissue reversible compartment model including blood volume. High correlations were observed between V(d) obtained using different input functions (R(2)=0.80-1.00) and between V(d) obtained with one- and two-tissue reversible compartment models (R(2)=0.75-0.94). A high correlation was observed between optimal V(d) and SUV after injection (R(2)=0.73). CONCLUSION: (R)-[(11)C]PK11195 kinetics in the knee were best described by a reversible single-tissue compartment model including blood volume. Applying metabolite corrections did not increase sensitivity. Due to the high correlation with V(d), SUV is a practical alternative for clinical use.

Disrupting actin filaments promotes efficient transfection of a leukemia cell line using cell adhesive protein-embedded carbonate apatite particles.

Tumor cells such as leukemia and lymphoma cells are obvious and attractive targets for gene therapy. Gene transfer and expression for cytokine and immunomodulatory molecules in various kinds of tumor cells have been shown to mediate tumor regression and antimetastatic effects. Moreover, genetically modified leukemia cells expressing costimulatory molecules or cytokines are likely to have significant therapeutic roles for patients with leukemia. One of the major hurdles to the successful implementation of these promising approaches is the lack of a suitable nanocarrier for transgene delivery and expression in a safe and effective manner. Recently, we reported on the development of a safe, efficient nanocarrier system of carbonate apatite that can assist both intracellular delivery and release of DNA, leading to very high level of transgene expression in cancer and primary cells. However, its efficiency in human lymphocytes is poor. We show here that nanocrystals of carbonate apatite, when electrostatically associated with fibronectin and/or E-cadherin-Fc, accelerated transgene delivery in a human T leukemia cell line (Jurkat). Moreover, transgene expression efficiency could be enhanced dramatically with the cell adhesive protein-embedded particles finally up to 150 times by selectively disrupting the actin filaments.

Localization of Z-protein in isolated Z-disk sheets of chicken leg muscle.

Immunoblotting studies with antisera against Z-protein, desmin, and alpha-actinin showed that Z-protein is clearly distinguishable from desmin and alpha-actinin. Z-protein is not a proteolytic product of another protein but is an intrinsic component of chicken breast muscle myofibrils. In these experiments, an SDS extract of intact muscle was first electrophoresed in a polyacrylamide gel, and then proteins were transferred to a nitrocellulose paper sheet. Detection of each protein on the sheet was made possible by the application of the indirect immunofluorescence technique with the respective antiserum. Immunofluorescence microscope studies using these antisera revealed that Z-protein has the same distribution as alpha-actinin in isolated Z-disk sheets. Anti-Z-protein antiserum and anti-alpha-actinin antiserum stained the interior of Z-disks. On the other hand, antiserum against desmin stained the periphery of Z-disks in isolated Z-disk sheets.

Elastic behavior of connectin filaments during thick filament movement in activated skeletal muscle.

Connectin (also called titin) is a huge, striated muscle protein that binds to thick filaments and links them to the Z-disc. Using an mAb that binds to connectin in the I-band region of the molecule, we studied the behavior of connectin in both relaxed and activated skinned rabbit psoas fibers by immunoelectron microscopy. In relaxed fibers, antibody binding is visualized as two extra striations per sarcomere arranged symmetrically about the M-line. These striations move away from both the nearest Z-disc and the thick filaments when the sarcomere is stretched, confirming the elastic behavior of connectin within the I-band of relaxed sarcomeres as previously observed by several investigators. When the fiber is activated, thick filaments in sarcomeres shorter than 2.8 microns tend to move from the center to the side of the sarcomere. This translocation of thick filaments within the sarcomere is accompanied by movement of the antibody label in the same direction. In that half-sarcomere in which the thick filaments move away from the Z-disc, the spacings between the Z-disc and the antibody and between the antibody and the thick filaments both increase. Conversely, on the side of the sarcomere in which the thick filaments move nearer to the Z-line, these spacings decrease. Regardless of whether I-band spacing is varied by stretch of a relaxed sarcomere or by active sliding of thick filaments within a sarcomere of constant length, the spacings between the Z-line and the antibody and between the antibody and the thick filaments increase with I-band length identically. These results indicate that the connectin filaments remain bound to the thick filaments in active fibers, and that the elastic properties of connectin are unaltered by calcium ions and cross-bridge activity.