Failure of stimulated skeletal muscle mainly contributed by passive force: an in vivo rabbit model

OBJECTIVE: To evaluate the role of active and passive muscle forces in the failure mechanism of stimulated muscle. DESIGN: An in vivo rabbit model. BACKGROUND: Eccentric contractions can result in a greater incidence of muscle injury. However, the relative role of the active and passive muscle force in the failure mechanism of the activated muscle is not well elucidated. METHODS: After anaesthesia, New Zealand white rabbits were fixed in a frame on a materials testing machine. The triceps surae muscle-tendon units were passively stretched to rupture with our without continuous nerve stimulation. The force and muscle length were simultaneously recorded. Active muscle force, passive muscle force, and ratio of the active to passive muscle were calculated and depicted against strain. RESULTS: The results showed that the mean maximal passive force of triceps surae muscle was 293.1 N at a strain of 38%. The mean peak active muscle force was 21.5 N at a strain of 21%. The ratio of active to passive muscle force reached its peak first, followed by the active muscle force, and then the passive muscle force. The ratio of active to passive muscle force at the peak total force was only 3.3%. CONCLUSIONS: The stimulated muscle can exert its maximal response at extreme physiological extension. Injury of the stimulated muscle is caused mainly by passive muscle force.     

Dose-dense regimen of temozolomide given every other week in patients with primary central nervous system tumors.

BACKGROUND: Temozolomide has shown activity and limited toxicity in patients with primary brain tumors at doses of 150-200 mg/m(2)/day on days 1-5 every 4 weeks. In this study, a new alternative dose-dense regimen of temozolomide was explored in patients with recurrent brain tumors. PATIENTS AND METHODS: In this study, we evaluated the safety, dose-limiting toxicity, maximum tolerated dose, recommended dose and activity of temozolomide given on days 1-3 and 14-16 every 28 days (one cycle). The starting daily dose was 200 mg/m(2) in a group of at least six patients, with subsequent increments of 50 mg/m(2) in groups of at least 12 patients until unacceptable toxicity was reached. Oral ondansetron (8 mg) was given 1 h prior to temozolomide administration. McDonald's criteria were used to evaluate antitumor activity. RESULTS: Seventy patients with brain tumors entered this study. The median number of prior chemotherapy treatments was two (range 1-3). Patients were assigned to one of four groups to receive temozolomide at daily doses of 200 (seven patients), 250 (13 patients), 300 (38 patients) and 350 mg/m(2)/day (12 patients). The absence of dose-limiting toxicity at cycle 1 led us to establish dose recommendations based on toxicity after repeated cycles. A total of 23, 72, 192 and 83 cycles were given at daily doses of 200, 250, 300 and 350 mg/m(2), respectively. Grade 3-4 thrombocytopenia was observed in 0/7, 1/13, 5/38 and 4/12 patients treated at doses of 200, 250, 300 and 350 mg/m(2)/day, respectively. Grade 3-4 neutropenia was observed in 1/7, 0/13, 3/38 and 4/12 patients treated with 200, 250, 300 and 350 mg/m(2)/day temozolomide, respectively. At a dose of 350 mg/m(2), sustained grade 2-3 thrombocytopenia did not allow treatment to be resumed at day 14 in >40% of patients, and this dose was considered to be the maximum tolerated dose. Thus, a dose of 300 mg/m(2)/day that was associated with <20% treatment delay due to sustained hematological toxicity was considered as the recommended dose. Objective responses were reported in 13 patients. CONCLUSIONS: Temozolomide can be given safely using a dose-dense regimen of 300 mg/m(2)/day for 3 consecutive days every 2 weeks in patients with recurrent brain tumors.     

Rapid engraftment of mast cells of donor origin in a case of acute myeloid leukemia with mast cell leukemia after allogeneic stem cell transplantation

Mastocytosis is a rare disease characterized by an abnormal increase of mast cells in tissues. We report a case of acute myeloid leukemia (AML) with t(8;21) and mast cell leukemia (MCL) in which the mastocytosis persisted after standard chemotherapy and allogeneic stem cell transplantation, although the myeloid leukemia achieved molecular complete remission soon after induction chemotherapy. Donor-type mast cells were noted on d31 after transplant. No c-kit mutation was found before or after the transplant. This represents the first reported case in which rapid engraftment of mast cells of donor origin was documented. Thus, the possibility that the mast cell originates from a common myeloid precursor cell may be questioned and a reactive process should be considered in some cases of systemic mastocytosis.     

Serum cholesterol in idiopathic and lupus-related protein-losing enteropathy

Abstract The characteristics of protein-losing enteropathy were evaluated in patients with systemic lupus erythematosus. Among the patients with systemic lupus erythematosus (n=380) in a tertiary hospital, we reviewed the records of seven patients with generalized edema, hypoalbuminemia without proteinuria and positive results on 99mTc-labelled human serum albumin scintigrams. Patient characteristics and laboratory findings were compared between these seven patients and patients with lupus enteritis (n=15) or idiopathic protein-losing enteropathy (n=11). Compared with the lupus enteritis patients, the erythrocyte sedimentation rate and serum total cholesterol levels were significantly increased in patients with systemic lupus erythematosus-related protein-losing enteropathy. Compared with idiopathic protein-losing enteropathy patients, the level of serum total cholesterol was significantly increased, but the level of serum albumin was decreased in patients with systemic lupus erythematosus-related protein-losing enteropathy. Among patients with systemic lupus erythematosus-related protein-losing enteropathy, four patients had high serum total cholesterol levels (>or=248 mg/dL) and achieved complete remission after receiving high doses of steroid treatment. However, three patients who had low serum total cholesterol levels (相似文献   

Potential prognostic value of leptin receptor in hepatocellular carcinoma

BACKGROUND: Obesity is associated with several human malignancies, including hepatocellular carcinoma (HCC). This association may result from the deregulated expression of adipokines. AIMS: To explore the potential role and the prognostic value of leptin receptor (Ob-R) in HCC. METHODS: 66 patients with pathologically confirmed HCC were included in this study. Immunohistochemistry was used to evaluate the expression of Ob-R, microvessel density (MVD) and Ki-67 index in these patients. Eventually, the profiles of Ob-R expression, obtained by a semiquantitative scoring system, were further correlated with Ki-67 expression, intratumour MVD, clinicopathological characteristics and overall survival. RESULTS: High Ob-R expression was seen in 53% of patients with HCC and was significantly correlated with intratumour MVD (high v low; 59.4 (3.2) v 44.7 (3.7); p = 0.004), but not with Ki-67 expression. In addition, Ob-R expression was inversely correlated with vascular invasion (p = 0.037), but not with other known clinicopathological characteristics. The Kaplan-Meier survival curve showed that high Ob-R expression was associated with a better overall survival (p = 0.027). Meanwhile, multivariate analysis showed that Ob-R expression was a significant determinant for HCC (odds ratio 0.02, 95% confidence interval 0.01 to 0.85; p = 0.041). CONCLUSION: Ob-R expression may have a potential role in the carcinogenesis of HCC. The positive association of Ob-R expression in the cancerous lesions of HCC with the survival outcome can be explained by its inverse correlation with vascular invasion, and may have prognostic value in HCC.     

Improved GFR estimation by combined creatinine and cystatin C measurements

Plasma creatinine may not reflect glomerular filtration rate (GFR) especially in the early stages of chronic kidney disease (CKD). Plasma cystatin C (cysC), however, has the potential to more accurately determine early GFR reduction. We sought to improve the creatinine-based GFR estimation by including cysC measurements. We derived a reference GFR from standard dual plasma sampling (99m)Tc-DTPA clearance in a training cohort of 376 randomly selected adult Chinese patients with CKD. We compared reference values to estimated GFR and applied multiple regression models to one equation based solely on cysC, and to another combining plasma creatinine (Pcr) and cysC measurements of the training cohort. The results were validated by testing an additional 191 patients. The difference, precision, and accuracy of the two estimates were compared with the modified Modification of Diet in Renal Disease (MDRD) equation for Chinese patients, and another estimate combining cysC and modified MDRD calculations. The estimated GFR combining Pcr and cysC measurements more accurately matched the reference GFR at all stages of CKD than the other equations, particularly in patients with near-normal kidney function.     

The anti-diabetic effects of ethanol extract from two variants of Artemisia princeps Pampanini in C57BL/KsJ-db/db mice.

The anti-diabetic effects of two variants of Artemisia princeps Pampanini, sajabalssuk (SB) and sajuarissuk (SS), were investigated in type 2 diabetic animal using their ethanol extracts. Male C57BL/KsJ-db/db (db/db) mice were divided into control, SB ethanol extract (SBE), SS ethanol extract (SSE), or rosiglitazone (RG) groups and their age-matched littermates (db/+) were used. Supplementation of the SBE (0.171 g/100g diet), SSE (0.154 g/100g diet), and RG (0.005 g/100g diet) improved glucose and insulin tolerance and significantly lowered blood glycosylated hemoglobin levels, as compared to the control group. Plasma insulin, C-peptide and glucagon levels in db/db mice were higher in the db/+ mice, however these values were significantly lowered by SBE, SSE or RG-supplement. Hepatic GK activity was significantly lower in the db/db mice than in the db/+ mice, while hepatic G6Pase activity was vice versa. Supplementation of SBE, SSE and RG reversed these hepatic glucose-regulating enzyme activities. In addition, SBE and SSE markedly increased the hepatic glycogen content and muscle ratio as compared to the control group, but they did not alter the food intake, body weight and plasma leptin level. The RG group, however, showed a significant increase in the food intake, body weight and plasma leptin. These results suggest that SBE and SSE exert an anti-diabetic effect in type 2 diabetic mice.     

Total hip replacement with a cementless acetabular component and a cemented femoral component in patients younger than fifty years of age

BACKGROUND: We have been using hybrid total hip arthroplasty (a cementless acetabular component and a cemented stem) in young patients. The purpose of this study was to determine the prevalence of aseptic loosening, polyethylene wear, and osteolysis after the use of this technique. METHODS: We studied a prospective consecutive series of sixty-four primary hybrid total hip replacements in fifty-five patients younger than fifty years old. There were forty-three men and twelve women; the average age at the time of the index operation was 43.4 years. The average duration of follow-up was 9.4 years. We used a cementless acetabular component without screw-holes and a cemented femoral component with a 22-mm head in all hips. Clinical follow-up with use of Harris hip ratings and radiographic follow-up were performed at six weeks; at three, six, and twelve months; and yearly thereafter. The sequential annual linear and volumetric wear rates were measured, and bone-remodeling and osteolysis were assessed. RESULTS: The mean preoperative Harris hip score was 44 points, which increased to 95 points at the time of final follow-up. No hip had aseptic loosening. One hip (2%) was revised because of late infection. The average linear wear (and standard deviation) was 0.96 +/- 0.066 mm, with an average annual rate of 0.096 +/- 0.013 mm. The average volumetric wear was 364.7 +/- 25.2 mm (3), with an average annual rate of 43.4 +/- 3.5 mm (3). Six hips (9%) had an osteolytic lesion of <1 cm in diameter in the calcar femorale (zone 7). CONCLUSIONS: Our results show that a hybrid arthroplasty with a cementless acetabular component and a smooth cemented femoral component (Ra, 0.6 mm) is effective for primary total hip replacement in young patients. Although there was no aseptic loosening and a low prevalence of osteolysis at the latest follow-up evaluation, the high rates of linear and volumetric wear of the polyethylene liner in these young patients remain a concern.