Biomedical subjects

S Saitoh

Publications and source records attributed to S Saitoh.

At least 19 recordsLinked to original sources

PubMed2001

Very-long-chain fatty acid-containing phospholipids accumulate in fatty acid synthase temperature-sensitive mutant strains of the fission yeast Schizosaccharomyces pombe fas2/lsd1.

Fission yeast lsd1 strains show aberrant mitosis with a lsd phenotype, large and small daughter nuclei, and a very thick septum, the phenotypic expression being temperature-sensitive. The lsd1(+) gene is the homologue of the budding yeast FAS2 gene encoding the fatty acid synthase alpha-subunit as reported previously (S. Saitoh, K. Takahashi, K. Nabeshima, Y. Yamashita, Y. Nakaseko, A. Hirata, M. Yanagida, J. Cell Biol. 134 (1996) 949--961). In this paper, lsd1 is considered to represent fas2. Here, three fas2 strains were investigated and found to have missense point mutations at different sites in the gene encoding the alpha-subunit of fatty acid synthase. The mutation affected only slightly the enzymatic activities monitored in vitro. Unexpectedly, abnormal phospholipids, phosphatidylcholine and phosphatidylethanolamine, both of which contain a very-long-chain fatty acyl residue (1-melissoyl-2-oleolyl-sn-glycero-3-phosphocholine and 1-melissoyl-2-oleolyl-sn-glycero-3-phosphoethanolamine), accumulated in fas2 strains in a temperature-sensitive manner. Rescue of the fas2 strains by addition of palmitate to the medium at restrictive temperature was accompanied by disappearance of these abnormal phospholipids. Accumulation of these lipids in membranes may cause alteration of various cellular functions.

Carbon Radioisotopes↗

PubMed2001

A pivotal role of cysteine 3 of Lck tyrosine kinase for localization to glycolipid-enriched microdomains and T cell activation.

Lck, a Src family protein tyrosine kinase (PTKs), is post-translationally modified by palmitoylation, a process thought to regulate the biological function, membrane affinity and glycolipid-enriched microdomain (GEM) localization of this molecule. To examine the importance of palmitoylation sites Cys3 and Cys5 in Lck, one or both of these residues was mutated to serine to create mutants S3, S5, and S3,5, respectively. Immunofluorescence and confocal microscopy of COS-7 cells transfected with these constructs showed that while S5 and S3 localized to the plasma membrane, S3,5 was localized to the cytoplasm, suggesting that palmitoylation at at least one site is essential for membrane localization. Sucrose gradient based fractionation of these mutants expressed in COS-7 cells showed that while S5 localized to GEMs in similar fashion to the wild type, GEM localization of S3 was severely inhibited. Expression of these mutants in Lck-negative JCaM1 cells showed that although S5 reconstituted activation of nuclear factor NFAT as per the wild type, S3 expression failed to do so. These results suggest that Cys3 of Lck plays a more important role than Cys5 in GEM localization and T cell activation. Additionally, it was found that the degree of T cell function recovery is positively correlated with the degree of Lck expression in GEMs.

Animals↗

PubMed2001

Efficacy of IFN therapy based on duration period of negative HCV-RNA during IFN administration.

We assessed the relationship between the duration period of negative hepatitis C virus (HCV)-RNA during interferon (IFN) therapy and the efficacy after prolonged IFN therapy in patients with HCV-genotype 1b and high virus load of more than 1 mega equivalents/ml (Meq/ml) retrospectively. A total of 100 patients who had HCV-genotype 1b and a high virus load of more than 1 Meq/ml and were treated with natural IFN-alpha for more than 12 months were enrolled in this trial. These patients were given 6 MU of IFN daily for 8 weeks, followed by three times weekly for another more than 44 weeks. The HCV-RNA pattern during IFN therapy according to negative or positive of the serum HCV-RNA by reverse transcription nested polymerase chain reaction (RT-nested PCR) from 2 months after the initiation of IFN to the termination of IFN were classified as follows: group 1: constant negative HCV-RNA (n=41 cases), group 2: constant positive HCV-RNA (n=35 cases), group 3: HCV-RNA pattern except for group 1 or group 2 (n=24 cases). A complete response (CR) was defined as negative HCV-RNA by RT-nested PCR at two points, 3 and 6 months after the completion of IFN therapy. CR rate was 58.5% (24 cases) in group 1, but CR rate in group 2 or group 3 was 0%. In group 1, the CR rate was 100% (10/10) in patients with negative HCV-RNA constantly for period of more than 24 months during IFN therapy. On the other hand, all patients who had positive HCV-RNA 2 months after the initiation of IFN did not get CR. In conclusion, it seems to us that the attainment of constantly negative HCV-RNA for the period of more than 24 months during IFN therapy is highly related to CR.

Journal Article↗

PubMed2001

Risk factors of hepatitis C virus-related liver cirrhosis in young adults: positive family history of liver disease and transporter associated with antigen processing 2(TAP2)*0201 Allele.

The aim of this study was to clinically characterize young patients with hepatitis-C-related cirrhosis. We compared 27 patients with liver cirrhosis (Group LC) who were anti-HCV positive, aged 40 years or less at the time of diagnosis, with 323 consecutive patients with HCV-related chronic hepatitis (Group CH) matched for age and gender. Furthermore, Group LC was divided into two arbitrary groups (29-35 years, n = 8 /36-40 years, n = 19), based on the age of patients at the time of diagnosis of liver cirrhosis. Patients' characteristics and family history were investigated, and the frequency of transporter associated with antigen processing 2 (TAP2) was determined. A family history of liver disease was present in 40.7% of Group LC but in 18.0% of Group CH (P < 0.05). The younger the age of diagnosis of cirrhosis in Group LC, the higher the frequency of a positive family history (29-35 years, 87.5%; 36-40 years, 21.1%, P < 0.05). The frequency of TAP2*0201 was significantly higher in young adult patients with HCV-related liver cirrhosis than in HCV carriers with normal ALT (P < 0.05), and tended to be higher than in uninfected normal subjects (P = 0.05). The cumulative survival rate of cirrhosis patients with family history of liver diseases was significantly lower than that of cirrhosis patients without such history (P < 0.05). Our findings suggest that a positive family history of liver disease and TAP2*0201 polymorphism may be risk factors for HCV-related liver cirrhosis in young adults.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

Incidence of the appearance of the red color sign on esophageal varices and its predictive factors: long-term observations of 359 patients with cirrhosis.

PURPOSE: The red color sign observed by endoscopic examination is a reliable predictive factor for variceal bleeding. The aim of this study was to calculate the incidence of the appearance of the red color sign and to evaluate its predictive factors. METHODS: Endoscopic examination was repeatedly performed in 359 consecutive patients diagnosed as having liver cirrhosis with or without esophageal varices, during a median follow-up period of 2651 days. RESULTS: The incidence of the appearance of the red color sign on esophageal varices at the end of the tenth year was compared among patients without varices (11.4%), those with small varices (45.4%), and those with mid-size varices (65.0%). The difference was significant (P < 0.0001). The number of varices (P = 0.0010), size of varices (P = 0.0064), platelet count (P = 0.0168), and alpha-fetoprotein level (P = 0.0207) were significantly correlated with the appearance of the red color sign, as estimated by the multivariate Cox hazard model. To exclude the influence of carcinogenesis, observation was stopped when hepatocellular carcinoma was discovered. Additive predictive factors with significance were: number of varices (P = 0.001), size of varices (P = 0.027), and platelet count (P = 0.0315). CONCLUSIONS: Endoscopic signs of esophageal varices and platelet count were significant predictors for the appearance of the red color sign.

Color↗

PubMed2001

Twice-daily administration of interferon-beta for chronic hepatitis C is not superior to a once-daily regimen.

PURPOSE: Although interferon (IFN) is commonly used for the treatment of chronic hepatitis C virus (HCV) infection, eradication of the virus occurs in only a small proportion of patients with genotype 1b and a high virus titer. Modified IFN therapies have been tried, with only limited benefit. Recently, the administration of IFN-beta twice per day has been reported to be more effective than the usual once-daily administration regimen. The aim of this study was to evaluate whether twice-daily IFN results in a sustained response in patients with chronic HCV infection with genotype 1b, and a high virus titer. METHODS: Twenty patients with genotype 1b and high HCV RNA level (more than 1 MEq/ml by branched DNA probe assay) were randomly assigned to receive either twice-daily 3 MU of IFN beta (group A) or once-daily 6 MU of IFN-beta (group B) for 4 weeks. All patients received a further daily dose of 6 MU IFN-beta for 12 weeks, followed by IFN-alfa three times a week for 16 weeks. RESULTS: Although a rapid fall in HCV RNA levels was noted in group A, a sustained response was observed in only one of nine patients in this group, and none of group B. Adverse effects of IFN were more frequent and pronounced in group A than in group B. CONCLUSIONS: We conclude that further modification, which combines the early strong anti-viral effects of the twice-daily regimen with long-term sustained response, is necessary for effective therapy of HCV patients with genotype 1b and high HCV RNA levels.

Adult↗

PubMed2001

Interferon therapy for flare-up of hepatitis B virus infection after emergence of lamivudine-induced YMDD motif mutant.

A 61-year-old man with chronic hepatitis B was treated with interferon (IFN)-alpha for flare-up after the emergence of a lamivudine-induced YMDD motif mutant. The YMDD mutant emerged 13 months after the initiation of lamivudine therapy. Despite this, lamivudine therapy was continued. Acute exacerbation occurred 25 months after the emergence of the YMDD mutant. Treatment with IFN-alpha resulted in rapid loss of hepatitis, B virus DNA, resolution of hepatitis, and clinical recovery.

Amino Acid Motifs↗

PubMed2001

Evaluation of quantitative measurements of hepatitis C virus RNA to predict sustained response to interferon by genotype.

Hepatitis C virus (HCV) virus load is one of the most important predictive factors for the outcome of interferon (IFN) therapy. Recent technological advances have allowed a more precise measurement of HCV load. However, the exact cutoff values that could be used to predict the outcome of IFN have not been established for each assay. Five recent quantitative assays were evaluated for the measurement of HCV (Amplicor monitor ver 1.0, Amplicor monitor ver 2.0 (GT), Amplicor monitor ver 2.0 (Cobas), Quantiplex branched DNA amplification (bDNA) ver 2.0 and HCV core protein level by enzyme immunosorbent assay) in 209 consecutive patients with chronic hepatitis C, who received IFN therapy. The results of the two second generation Amplicor monitor tests (GT and Cobas) showed the best correlation (r = 0.930), but the other tests also showed relatively good correlations (r = 0.646-0.925). Each method predicted the effect of IFN with comparable predictive efficacy, ranging from 77.0 to 80.8%. Receiver operating characteristic (ROC) curve analysis showed that Amplicor monitor ver 2.0 and bDNA ver 2.0 are superior in predicting the response in genotype 2a. The best cutoff value for predicting the response to IFN was different by genotype, which should be considered in selecting candidates for IFN treatment.

Adult↗

PubMed2001

Multiple endothelial injury in epicardial coronary artery induces downstream microvascular spasm as well as remodeling partly via thromboxane A2.

OBJECTIVES: The study was undertaken to develop a coronary microvascular spasm model in pigs by repeated epicardial coronary artery endothelial injury. BACKGROUND: The pathophysiologic mechanisms responsible for coronary microvascular spasm remain unclear, in large part because a suitable animal model has yet to be found. METHODS: Balloon endothelial denudation was done just distal to the site of an implanted Doppler flowmeter in the left anterior descending coronary artery (LAD) every two weeks for a total of four times. Changes in LAD blood flow by intracoronary administration of vasoactive agents were assessed before each denudation. RESULTS: In the epicardial LAD endothelial denudation pigs, decreases in LAD blood flow caused by acetylcholine were augmented. Before denudation, it was - 15 +/- 4%, and at week 8 (i.e., two weeks after the fourth denudation) it was -100% (i.e., zero flow [p < 0.01]). The LAD flow changes in response to 5-hydroxytryptamine (5-HT) changed from an increase to a decrease, accompanied by medial thickening of microvessels in the LAD perfusion area. These flow responses were observed without significant changes in LAD diameter. In contrast, the LAD blood flow responses to acetylcholine and 5-HT did not change throughout the experiment in pigs given aspirin and a thromboxane A2 (TXA2) synthase inhibitor orally. CONCLUSIONS: This microvascular spasm model indicates that hypersensitivity to vasoactive substances in the microvascular beds as well as microvascular remodeling are brought about partly through TXA2. This model should be useful for examining the pathophysiology and treatment of microvascular angina.

Animals↗

PubMed2001

Randomized controlled clinical trial of lymphoblastoid interferon-alpha for chronic hepatitis C.

Objective: Most of chronic hepatitis C patients with HCV-genotype 1 and a high virus load fail to eradicate the HCV-RNA by the interferon (IFN) or IFN/ribavirin therapy. But in these patients, IFN is often effective with regard to normalization of alanine aminotransferase (ALT). We had therefore the following two randomized controlled clinical trials to evaluate the effect of IFN which reduce ALT and maintain normalization of ALT. One approach (study 1) was to compare the efficacy of a 6 month course of three different dosages of recombinant IFN-alpha-2a in patients with chronic hepatitis C associated with HCV-genotype 1b and a high serum HCV-RNA level of more than 1 Meq/ml. Another approach (study 2) was to make clear the significance of an additional 6 month course of IFN in patients who had biochemical response during the first 6 month course of IFN (study 1). Methods: (1) Study 1; 45 patients with HCV-genotype 1b and a high serum HCV-RNA level of more than 1 Meq/ml were randomly assigned into three equal groups; group 1 was treated with 3 million units (MU), group 2 with 6 MU and group 3 with 9 MU. They were treated with IFN 3 times weekly for 6 months. Biochemical response was defined as normalization of ALT at the 6 month after initiation of IFN; (2) Study 2; Subsequently, of 23 patients with biochemical response by the first study, 22 were randomly assigned to two groups; patients in group A were continued to receive 3 MU of IFN-alpha-2a three times a week for an additional 6 months and patients in group B were discontinued IFN therapy. Results: (1) Study 1; One patient in group 1, three in group 2 and five in group 3 withdrew from IFN therapy because of IFN-related side-effects. Biochemical response was 10 (66.7%) patients of group 1,8 (53.3%) of group 2 and 5 (33%) of group 3 by the intention-to-treat (ITT) analysis. The biochemical response rate in group 1 was slightly higher than that in other two groups by the Cochran Armitage two-tailed test (P=0.066). With respect to serum HCV-RNA level, one patient in group 1, six patients in group 2 and four patients in group 3 became negative for HCV-RNA by reversed transcription nested-polymerase chain reaction (RT nested-PCR) at the end point of first 6 month course of IFN; (2) Study 2; The maintenance rate of ALT normalization was 88.9% (9/11) in group A and 11.1% (2/11) in group B. The maintenance rate of ALT normalization in group A was significantly higher than that in group B by the Fisher exact's test (P=0.0089). With respect to serum HCV-RNA level by RT nested-PCR, four patients in group A had negative HCV-RNA at the end of an additional IFN therapy. On the other hand, all the patients in group B had positive HCV-RNA at the same time. Conclusion: Our data suggested that a prolonged IFN therapy using a dose of 3 MU of IFN-alpha-2a is safe strategy to reduce ALT and to maintain ALT normalization in patients with HCV-genotype 1b and a high serum HCV-RNA level of more than 1 Meq/ml.

Journal Article↗

PubMed2001

A novel maternally expressed gene, ATP10C, encodes a putative aminophospholipid translocase associated with Angelman syndrome.

Lack of a maternal contribution to the genome at the imprinted domain on proximal chromosome 15 causes Angelman syndrome (AS) associated with neurobehavioral anomalies that include severe mental retardation, ataxia and epilepsy. Although AS patients have infrequent mutations in the gene encoding an E6-AP ubiquitin ligase required for long-term synaptic potentiation (LTP), most cases are attributed to de novo maternal deletions of 15q11-q13. We report here that a novel maternally expressed gene, ATP10C, maps within the most common interval of deletion and that ATP10C expression is virtually absent from AS patients with imprinting mutations, as well as from patients with maternal deletions of 15q11-q13.

Adenosine Triphosphatases↗

PubMed2001

Long-term interferon therapy for 1 year or longer reduces the hepatocellular carcinogenesis rate in patients with liver cirrhosis caused by hepatitis C virus: a pilot study.

BACKGROUND AND METHODS: In order to elucidate the influence of a long-term administration of interferon on the appearance rates of hepatocellular carcinoma (HCC) in hepatitis C virus (HCV)-related cirrhosis, we retrospectively analyzed 694 patients with cirrhosis. A total of 113 patients underwent interferon therapy, including 25 patients with a long-term administration of interferon for 1 year or more, and the other 581 patients received no antiviral drugs. RESULTS: Crude cumulative appearance rates of HCC in the interferon and the untreated groups were 14.1, and 28.4% at the end of the 5th year, and 36.7 and 52.5% at the end of the 10th year, respectively (P = 0.0028). As there was a waiting time between diagnosis and treatment (median 2.0 months, average 21.3 months) in the treated group, Cox proportional hazard analysis using a time-dependent covariate was introduced to evaluate the anticarcinogenic effect of interferon. Although male sex, higher alpha-fetoprotein, older age, lower albumin concentration, and lower platelet count significantly increased the carcinogenesis rate, interferon was not a significant contributing factor to the carcinogenesis rate as a whole (hazard ratio = 0.83, P= 0.32). When the patients with interferon were divided into two groups according to therapy duration, long-term interferon therapy significantly decreased the hepatocellular carcinogenesis rate after an adjustment by significant covariates (hazard ratio = 0.28, P= 0.0048). CONCLUSION: When interferon is administered for 12 months or longer, effective cancer prevention will be achieved, even in patients with HCV-related cirrhosis.

Adult↗

PubMed2001

The 'superficial' peroneal artery: a variation in cutaneous branching from the peroneal artery, nourishing the distal third of the leg.

Two different vascular patterns were encountered in cutaneous branches from the peroneal artery to the posterolateral aspect of the distal third of the leg in 22 flaps from 22 patients who underwent cutaneous or osteocutaneous peroneal flap surgery. In the type 1 vascular pattern, a branch from the peroneal artery, named the 'superficial peroneal artery', nourished the posterolateral aspect of the leg by splitting into several septocutaneous branches. In the type 2 pattern a few septocutaneous branches originated directly from the main peroneal artery and nourished the same area as that fed by the type 1 branch. The type 1 vascular pattern has not been reported to date but was seen in nine out of the 22 consecutive peroneal flaps. The superficial peroneal artery, with its considerable vascular diameter, may serve as a recipient vessel for free flaps or may serve as a donor nutrient vessel for a cutaneous flap, which can be transferred without sacrificing the main peroneal artery. Awareness of these two vascular patterns in the distal third of the leg should also help to reduce the small percentage of skin-flap failures that occur when the cutaneous or osteocutaneous peroneal flap is used.

Adult↗

PubMed2001

Blunted peripheral vasodilatory response is a hallmark of progressive deterioration in mild to moderate congestive heart failure.

BACKGROUND: Several reports have shown that dilatory response to acetylcholine (ACh) and nitroprusside (SNP) is blunted in the limb vasculature in patients with congestive heart failure (CHF). However, it is not yet known whether this vascular dysfunction is related to clinical outcome. We have examined the relationship between peripheral vasodilatory response and prognosis of CHF. METHODS AND RESULTS: A total of 46 patients with mild to moderate CHF were enrolled (mean age 56 years). Changes in forearm blood flow (FBF) during intra-arterial infusion of ACh and SNP were determined by plethysmography. FBF changes above baseline for each dose were cumulated and used as an index of endothelium-dependent (ACh) response and endothelium-independent (SNP) response, respectively. During the follow-up period (mean 32 months), 9 patients were admitted to the hospital for treatment of worsening refractory CHF, and 6 patients died suddenly or developed life-threatening arrhythmia. By Kaplan-Meier analysis, when all cardiac events were included, no significant differences were observed between any levels of vascular response in terms of prognosis. However, when deterioration events were analyzed separately, patients with SNP responses below the median (7.4 mL/min/dL) had significantly higher rates of hospital admission caused by worsening CHF than those with above the median responses (P <.05). This relationship was not found between ACh response and clinical outcome. By Cox multivariate analysis, blunted vasodilatory response to SNP was a significant predictor of worsening CHF (chi(2) = 3.95; P <.05). CONCLUSION: This study has shown that patients with mild to moderate CHF showing a blunted vascular response to SNP rather than ACh were admitted to the hospital more frequently because of deterioration of CHF. This finding suggests that changes in vascular smooth muscle and/or vascular structure in the peripheral vasculature may be a critical element in the worsening of CHF.

Acetylcholine↗

PubMed2001

Gender difference in the relationships among hyperleptinemia, hyperinsulinemia, and hypertension.

Studies reveals that plasma leptin levels (LEP) in females are higher than those in males, and that LEP in hypertensive subjects are higher than those in BMI-matched normotensive subjects. To investigate the relationships among LEP, blood pressure (BP) and insulin sensitivity, we studied these relationships in 133 Japanese males and 263 females. LEP were positively correlated with BP, body mass index, body fat mass (FM) and homeostasis model assessment (HOMA). Regression analysis in which age and FM were adjusted showed LEP were associated with BP and HOMA. Even with adjustment by age, FM and HOMA, LEP were still positively correlated BP in males. LEP in insulin-resistant hypertensives was significantly higher than those in insulin-sensitive hypertensives, in insulin-sensitive normotensives and in insulin-resistant normotensives in males. However, in females, a significantly higher LEP was observed in insulin-resistant subjects than in insulin-sensitive subjects regardless of hypertension. These data suggest that it would be sexual difference in the relationships among hyperleptinemia, hyperinsulinemia and hypertension.

Adult↗

PubMed2001

A family of multiple endocrine neoplasia type 2A with the RET proto-oncogene mutation in codon 618 (Cys-->Arg).

Multiple endocrine neoplasia type 2 (MEN-2) is a hereditary syndrome characterized by medullary thyroid carcinoma (MTC), pheochromocytoma and hyperplasia or adenoma of the parathyroid gland with hyperparathyroidism. Recent genetic studies have identified the presence of germline missense mutations in the RET proto-oncogene in almost 100% of MEN-2 patients. We report here three generations of one MEN-2 family with rare missense mutation at codon 618 (Cys-->Arg) of the RET proto-oncogene. The first patient was surgically treated at the age of 63 years but died of bone metastasis. His two children (29-year-old daughter and 25-year-old son) were treated surgically for MTC and neck lymph node metastasis. Germline mutations of the RET proto-oncogene of these three MTC patients and two children of the 29-year-old daughter (9-year-old female and 7-year-old male) were examined. Three MTC patients and the 9-year-old female possessed the mutation. The phenotype of the family with this rare point mutation of the RET proto-oncogene is reported.

Adult↗

PubMed2001

Lamivudine therapy for spontaneously occurring severe acute exacerbation in chronic hepatitis B virus infection: a preliminary study.

OBJECTIVE: The nucleoside analogue lamivudine, a potent inhibitor of hepatitis B virus replication, has shown notable results in treating chronic hepatitis B. However, lamivudine has not been specifically tested for effectiveness against spontaneously occurring severe acute exacerbations of hepatitis in patients chronically infected with this virus. We addressed this issue in a pilot study. METHODS: Ten patients with chronic hepatitis B developed severe acute exacerbation spontaneously during follow-up; 3 of them developed hepatic failure shortly before entering the trial. Lamivudine was administered long-term to the 10 patients at a daily oral dose of 100 or 300 mg. RESULTS: All 3 patients with hepatic failure at initiation of treatment recovered dramatically. Of the remaining 7 patients, 5 recovered rapidly with lamivudine, but 2 progressed quickly to hepatic failure despite treatment. One died of sepsis and the other of multiorgan failure. In the 8 survivors, serum alanine transaminase activity decreased rapidly to normal with lamivudine therapy, and serum hepatitis B virus DNA level declined rapidly to undetectable levels. Serum total bilirubin concentrations normalized somewhat later. Prothrombin time improved steadily and gradually. Hepatitis B e antigen elimination or seroconversion was achieved in 3 survivors. No adverse effects were noted in any patient. All survivors had good quality of life with long-term lamivudine monotherapy. CONCLUSIONS: Lamivudine is effective, safe, and well tolerated by patients with spontaneous, severe, acute exacerbation complicating chronic hepatitis B virus infection, even in the presence of hepatic failure. Lamivudine appears to be an attractive therapeutic option and may represent the best choice.

Acute Disease↗

PubMed2001

Effects of the Chinese medicine Jiang-Tang-Ke-Li on insulin resistance in fructose-fed rats.

The aim of this study was to determine the effect of Jiang-Tang-Ke-Li (JTKL), a Chinese medicine used to treat diabetes mellitus, on insulin resistance and hypertension in fructose-fed rats (FFR). Six-week-old male Sprague-Dawley rats were fed either normal rat chow (control) or a fructose-rich chow (FFR) for 6 weeks. For the last 2 weeks of the 6-week period of either diet, the rats were treated by gavage with gum arabic solution as a vehicle (control or FFR) or JTKL (3.24 g/kg/day; FFR+JT), and then an euglycemic hyperinsulinemic glucose clamp technique was performed to estimate insulin sensitivity. Systolic blood pressure was measured each week of the 6-week period. At the end of the glucose clamp, the soleus and extensor digitorum longus (EDL) muscles were dissected out for determination of the role of tumor necrosis factor (TNF)-alpha by an ELISA assay. Systolic blood pressures in the FFR groups were significantly higher than that in the control group, although there was no effect on systolic blood pressure for the last 2 weeks of treatment with JTKL. The average rate of glucose infusion during the glucose clamp, as an index of insulin sensitivity (M value), was significantly lower in the FFR than in the control rats, and treatment with JTKL for 2 weeks significantly increased the M value to that of control. TNF-alpha levels were significantly higher in the soleus and EDL muscles of the FFR (480+/-46 and 570+/-45 pg/g wet tissue in the soleus and EDL muscles, respectively) than in those of the control rats (177+/-34 and 206+/-33 pg/g wet tissue in the soleus and EDL muscles, respectively; p<0.01). Treatment with JTKL for 2 weeks significantly lowered TNF-alpha levels to the control levels (189+/-22 and 239+/-92 pg/g wet tissue in the soleus and EDL muscles, respectively). The results suggest that the Chinese medicine JTKL improves insulin resistance and modulates TNF-alpha in the soleus and EDL muscles in hypertensive and insulin-resistant fructose-fed rats.

Animals↗