Hit to lead SAR study on benzoxazole derivatives for an NPY Y5 antagonist

We report a hit to lead study on a novel benzoxazole NPY Y5 antagonist. Starting from HTS hit 1, structure-activity relationships were developed. Compound 12 showed reduction of food intake and a tendency to suppress body weight gain over the 21-day experimental period.

Beneficial effects of leptin on glycaemic and lipid control in a mouse model of type 2 diabetes with increased adiposity induced by streptozotocin and a high-fat diet

AIMS/HYPOTHESIS

We have previously demonstrated the therapeutic usefulness of leptin in lipoatrophic diabetes and insulin-deficient diabetes in mouse models and could also demonstrate its dramatic effects on lipoatrophic diabetes in humans. The aim of the present study was to explore the therapeutic usefulness of leptin in a mouse model of type 2 diabetes with increased adiposity.

METHODS

To generate a mouse model mimicking human type 2 diabetes with increased adiposity, we used a combination of low-dose streptozotocin (STZ, 120 microg/g body weight) and high-fat diet (HFD, 45% of energy as fat). Recombinant mouse leptin was infused chronically (20 ng [g body weight](-1) h(-1)) for 14 days using a mini-osmotic pump. The effects of leptin on food intake, body weight, metabolic variables, tissue triacylglycerol content and AMP-activated protein kinase (AMPK) activity were examined.

RESULTS

Low-dose STZ injection led to a substantial reduction of plasma insulin levels and hyperglycaemia. Subsequent HFD feeding increased adiposity and induced insulin resistance and further augmentation of hyperglycaemia. In this model mouse mimicking human type 2 diabetes (STZ/HFD), continuous leptin infusion reduced food intake and body weight and improved glucose and lipid metabolism with enhancement of insulin sensitivity. Leptin also decreased liver and skeletal muscle triacylglycerol content accompanied by an increase of alpha2 AMPK activity in skeletal muscle. Pair-feeding experiments demonstrated that leptin improved glucose and lipid metabolism independently of the food intake reduction.

CONCLUSIONS/INTERPRETATION

This study demonstrates the beneficial effects of leptin on glycaemic and lipid control in a mouse model of type 2 diabetes with increased adiposity, indicating the possible clinical usefulness of leptin as a new glucose-lowering drug in humans.

Altered expression of matrix-related molecules in the development of chronic Thy1.1 nephritis

BACKGROUND/AIM

Matrix production and degradation are critically important in chronic nephritis. Our aim was to investigate the precise expression of matrix-related molecules which is essential for understanding the pathogenesis of renal disease.

METHODS

Chronic nephritis was induced by a single injection of anti-Thy1.1 antibody to unilaterally nephrectomized rats. RNA was extracted from renal cortex and isolated glomeruli 4, 7, and 10 weeks after the antibody injection. Matrix-related gene expressions were measured by polymerase chain reaction. The expression of alpha1(IV) and alpha3(IV) collagens was studied by immunohistochemistry. The gelatinolytic activity in the glomeruli was assayed by gelatin zymography.

RESULTS

Polymerase chain reaction revealed an increase of alpha1(IV) in both glomeruli and renal cortex from nephritic rats. In contrast, the expression of alpha3(IV), normally a component of the glomerular basement membrane, was decreased in nephritic animals. Immunohistochemistry confirmed the finding that alpha1(IV) and alpha3(IV) were up- and downregulated, respectively, in the glomeruli. Gene expression and activity of matrix metalloproteinase 2 were enhanced, while those of matrix metalloproteinase 9 were clearly suppressed in nephritis.

CONCLUSIONS

Downregulation of alpha3(IV) and enhancement of the matrix metalloproteinase-2 activity in the glomeruli may contribute to the glomerular damage by altering the glomerular basement membrane components. Impairment of the glomerular basement membrane integrity may possibly be implicated in irreversible renal dysfunction.

Skeletal muscle AMP-activated protein kinase phosphorylation parallels metabolic phenotype in leptin transgenic mice under dietary modification

Leptin augments glucose and lipid metabolism independent of its effect on satiety. Administration of leptin in rodents increases skeletal muscle beta-oxidation by activating AMP-activated protein kinase (AMPK). We previously reported that, as hyperleptinemic as obese human subjects, transgenic skinny mice overexpressing leptin in liver (LepTg) exhibit enhanced insulin sensitivity and lipid clearance. To assess skeletal muscle AMPK activity in leptin-sensitive and -insensitive states, we examined phosphorylation of AMPK and its target, acetyl CoA carboxylase (ACC), in muscles from LepTg under dietary modification. Here we show that phosphorylation of AMPK and ACC are chronically augmented in LepTg soleus muscle, with a concomitant increase in the AMP-to-ATP ratio and a significant decrease in tissue triglyceride content. Despite preexisting hyperleptinemia, high-fat diet (HFD)-fed LepTg develop obesity, insulin-resistance, and hyperlipidemia. In parallel, elevated soleus AMPK and ACC phosphorylation in regular diet-fed LepTg is attenuated, and tissue triglyceride content is increased in those given HFD. Of note, substitution of HFD with regular diet causes a robust recovery of soleus AMPK and ACC phosphorylation in LepTg, with a higher rate of body weight reduction and a regain of insulin sensitivity. In conclusion, soleus AMPK and ACC phosphorylation in LepTg changes in parallel with its insulin sensitivity under dietary modification, suggesting a close association between skeletal muscle AMPK activity and sensitivity to leptin.

Facilitatory role of NO in neural norepinephrine release in the rat kidney

We examined modulation by nitric oxide (NO) of sympathetic neurotransmitter release and vasoconstriction in the isolated pump-perfused rat kidney. Electrical renal nerve stimulation (RNS; 1 and 2 Hz) increased renal perfusion pressure and renal norepinephrine (NE) efflux. Nonselective NO synthase (NOS) inhibitors [N(omega)-nitro-L-arginine methyl ester (L-NAME) or N(omega)-nitro-L-arginine], but not a selective neuronal NO synthase inhibitor (7-nitroindazole sodium salt), suppressed the NE efflux response and enhanced the perfusion pressure response. Pretreatment with L-arginine prevented the effects of L-NAME on the RNS-induced responses. 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), which eliminates NO by oxidizing it to NO(2), suppressed the NE efflux response, whereas the perfusion pressure response was less susceptible to carboxy-PTIO. 8-Bromoguanosine cGMP suppressed and a guanylate cyclase inhibitor [4H-8-bromo-1,2,4-oxadiazolo(3,4-d)benz(b)(1,4)oxazin-1-one] enhanced the RNS-induced perfusion pressure response, but neither of these drugs affected the NE efflux response. These results suggest that endogenous NO facilitates the NE release through cGMP-independent mechanisms, NO metabolites formed after NO(2) rather than NO itself counteract the vasoconstriction, and neuronal NOS does not contribute to these modulatory mechanisms in the sympathetic nervous system of the rat kidney.

A case of submandibular malignant rhabdoid tumor transformed from papillary thyroid carcinoma

Malignant rhabdoid tumor (MRT) in the neck region is very rare. We report a case of MRT in a 60-year-old woman who had a history of papillary carcinoma of the thyroid gland 7 years previously. One year before admission, in 1995, thyroid carcinoma recurred, and the tumor contained a small undifferentiated region with rhabdoid features. The tumor in 1996 consisted of round to oval rhabdoid cells with abundant cytoplasm, and the growth pattern was diffuse and infiltrative, with no papillary structures. We therefore concluded that the lesion was MRT, transformed from papillary thyroid carcinoma.

Frequent loss of heterozygosity at 3p25-p26 is associated with invasive oral squamous cell carcinoma

Recent molecular evidence suggests that allelic deletions of chromosomes are involved in the carcinogenesis of various neoplasms, including oral squamous cell carcinoma (OSCC). To determine the role of 3p deletions in Japanese OSCC and to define the localization of putative tumor suppressor genes, we initially examined loss of heterozygosity (LOH), using nine microsatellite markers in 36 OSCCs and 28 oral epithelial dysplastic lesions (OEDLs). LOH on chromosome 3p was observed at one or more loci in 72% of OSCCs and 18% of OEDLs. Fourteen (61%) of 23 OSCC patients informative at D3S2450 (3pter-p24.2) showed LOH most frequently, in contrast to OEDL, where LOH was never seen at this locus. Interestingly, we found a significant association between an allelic deletion at this locus and the histologic grade of mode of tumor invasion. Therefore, we also examined allelic deletion on chromosome 3p telomeric to where D3S2450 was located. A common deletion region was identified between D3S2450 and D3S3591. Our results provide evidence for the presence of a tumor suppressor gene in a 0.8-cM region bordered by D3S2450 and D3S3591 at 3p25-p26, which may play a role in carcinogenesis and invasion of OSCC.

Clinical features of fulminant hepatitis in Nagasaki Prefecture, Japan

OBJECTIVE

Fulminant hepatitis is a rare but fatal disease. In the present study, we examined the changes in etiology and prognosis of fulminant hepatitis in Nagasaki Prefecture, Japan between 1980 to 1999.

METHODS

Eighty-one patients with fulminant hepatitis admitted to our hospitals from 1980 to 1999 were examined with respect to the etiology and prognosis.

RESULTS

Fulminant hepatitis was due to hepatitis A virus in 2 (12%) cases, hepatitis B virus in 18 (22%) cases, unknown etiology in 50 (62%) cases, and drug-induced in 11(14%) cases. The number of cases in the first half of the study (1980-1989) was 47 and that of the latter half (1990-1999) was 34 cases. The incidence of fulminant hepatitis type B also decreased from 14 cases (30%) to 4 cases (12%) during these periods. The overall survival rate of fulminant hepatitis was 32%; it was equal in fulminant hepatitis type B, fulminant hepatitis of unknown etiology and fulminant drug-induced hepatitis. The survival rate of fulminant hepatitis type A was 100%, though only two cases were identified. Retrospectively, the survival rate in patients with a pre-encephalopathy period of < or = 10 days and aged < or = 39 years was significantly higher than in patients > or = 40 years of age (p<0.01). There was no difference between the two age groups when pre-encephalopathy period was > or = 11 days.

CONCLUSIONS

The incidence of fulminant hepatitis especially that of fulminant hepatitis type B in Nagasaki Prefecture has decreased in recent years. The survival rate is significantly higher in younger patients with a short pre-encephalopathy period.

Gene expression of GLUT isoforms and VHL in oral squamous cell carcinoma

In human oral squamous cell carcinoma (OSCC) cell lines, we detected atypical mRNA expression of GLUT2 and/or GLUT4 in addition to enhanced expression of GLUT1 mRNA using RT-PCR. In semi-quantitative reverse transcription-polymerase chain reaction analysis of mRNA expression in OSCC cell lines, we found an inverse relationship between mRNA expression of von Hippel-Lindau (VHL) and that of GLUT1, with no apparent influence on the expression of other GLUTs. These findings suggest that the reduction of VHL may play a critical role in glucose uptake of OSCC cell lines, with enhancement of GLUT1 expression.

Re-analysis of clinical features of 89 patients with autoimmune hepatitis using the revised scoring system proposed by the International Autoimmune Hepatitis Group

OBJECTIVE

The diagnostic criteria of autoimmune hepatitis (AIH) were recently modified by the International Autoimmune Hepatitis Group. This study was performed to assess the impact of the revised scoring system on the diagnosis of AIH.

PATIENTS AND METHODS

We re-analyzed the clinical features of 89 patients diagnosed as AIH in Nagasaki Prefecture, Japan, using the revised scoring system, and compared the scores and final diagnosis with our previously published results using the original system.

RESULTS

Of the 89 patients with AIH, 40 (45%) were classified using the new system as "definite" AIH, 41 (46%) as "probable" AIH, and 8 (9%) patients were categorized as "others". Of these, 37 (42%), 35 (39%), and 4 (4%) patients who were classified as "definite", "probable", and "others" by the original system remained in the same category by the revised system, respectively. However, 3, 4, and 6 patients were re-categorized as "definite" from "probable", "others" from "probable", and "probable" from "definite", respectively. The difference in aggregate scores between the above two systems ranged from -5 to +2. The main contributing factors to the changes in aggregate AIH score were "other autoimmune disease(s)" and "interface hepatitis without lobular involvement and bridging necrosis on liver histology". However, the main contributing factors to the demotions from "definite" to "probable" and form "probable" to "others" were those related to the characteristics of biliary diseases, i.e., antimitochondrial antibody positive, biliary changes in liver histology, and alkaline phosphatase: aspartate aminotransferase ratio between 1.5 and 3.0. Moreover, two patients who had no histological evidence of AIH were both re-categorized as "others" from "probable" AIH.

CONCLUSION

Our results indicated that the diagnosis, whether based on the revised or original system, was the same in the majority of AIH patients, but the revised scoring system excluded cases who had features suggestive of biliary diseases from "definite" AIH, and also confirmed that a diagnosis of "definite" AIH should not be made without liver histology.

Indication for epidural morphine for the relief of intractable pain in advanced oral cancer: report of four cases

It can be difficult to manage the pain of advanced oral cancer. We present four patients in whom epidural morphine was used for intractable pain at primary or metastatic sites. For pain supplied by the trigeminal or cervical nerve a small dose of morphine was given through an epidural catheter inserted into the epidural space through C7-Th1. A favourable clinical response was achieved in three. In particular, in one patient who was given continuous morphine using a computerized ambulatory drug delivery system, we achieved excellent efficacy and stable control of pain. We think that the effect of the epidural morphine was decreased in the patient who did not respond because he had previously been treated with high oral doses. The present study confirmed that morphine given epidurally in small doses has a strong and prolonged analgesic action with less toxicity than when given orally.

Histological study on pN upgrading of oral cancer

The International Union Against Cancer (UICC) does not define the number of sections required from each regional lymph node to record pTNM classification. This study was designed to clarify the incidence of occult metastasis and to assess the pN upgrading of patients with oral cancer. Ultimately, this study led to a proposal for appropriate semiserial sectioning guidelines. Five hundred fifty-four nonmetastatic cervical lymph nodes taken from 73 patients with oral cancer were subjected to hematoxylin-eosin (HE) staining and keratin immunohistochemistry. Micrometastases, defined as foci < or =3 mm, were detected in 29 sites of 23 lymph nodes (4.2%) of 16 patients (21.9%). In 9 patients (12.3%) pN upgrading was needed: in 6 from pN0 to pN1, in 1 from pN0 to pN2b, and in 2 from pN1 to pN2b. The remaining 13 lymph nodes with occult metastasis were found in 5 pN2b and 2 pN2c patients, resulting in no pN upgrading. Occult metastasis was also detected in 6 small lymph nodes < or =5 mm in diameter. The average minor axis of the micrometastasis was 1.36-/+0.85 mm. We propose that the lymph nodes should be cut and examined at 1-mm intervals to detect micrometastatic foci and to evaluate the pN classification accurately.

Genetic diagnosis of micrometastasis based on SCC antigen mRNA in cervical lymph nodes of head and neck cancer

This study is designed to assess gene expression of squamous cell carcinoma antigen (SCCA) mRNA to detect micrometastases in cervical lymph nodes (LNs) of head and neck cancer. We examined the expression of SCCA mRNA in 12 primary tumors and 212 cervical LNs (101 LNs taken from 8 patients with tongue cancer, 71 from 7 patients with gingival cancer, 19 from 2 patients with laryngeal cancer, 9 from 2 patients with pharyngeal cancer, 7 from 1 patient with cancer of the buccal mucosa, and 5 from 1 patient with cancer of floor of the mouth). Detectability of metastatic LNs by nested and single reverse transcriptase-polymerase chain reaction (RT-PCR) was compared with semiserial sections (hematoxylin-eosin staining and keratin immunostaining). All primary tumors expressed SCCA mRNA. Of 198 histologically metastasis-negative nodes, SCCA mRNA was detected in 37 (18.7%) by nested PCR. Eleven micrometastatic foci in 9 LNs (4.6%) were discovered by semiserial sectioning. This suggests that SCCA mRNA is a promising tumor marker for detecting the micrometastases in cervical LNs of head and neck cancer.

Clinical usefulness of telomerase assay for the detection of lymph node metastasis in patients with oral malignancy

OBJECTIVE

Telomerase is considered a diagnostic marker of malignancy. We investigated the usefulness of telomerase assay for the detection of lymph node micrometastasis.

METHODS

Sixteen cervical lymph nodes with metastasis of oral cancer and 20 benign lymph nodes were studied. The oral cancer cell line was used to estimate the sensitivity for telomerase assay. Telomerase activity was measured by semiquantitative telomeric repeat amplification protocol.

RESULTS

There was a significant difference between malignant and benign lymph nodes. The telomerase activity of 50 mg of lymph nodes with 103 or more cancer cells differed from that of control lymph nodes. Lymph nodes with 102 or fewer tumor cells expressed similar levels as benign lymph nodes.

CONCLUSIONS

In addition to routine histologic examination, telomerase assay is considered a useful tool for the detection of lymph node metastasis in patients with oral malignancy.

COLLABORATIVE WORK TO EVALUATE TOXICITY ON MALE REPRODUCTIVE ORGANS BY REPEATED DOSE STUDIES IN RATS : 5)EFFECTS OF REPEATED DOSES OF FLUTAMIDE FOR 2 AND 4 WEEKS

Flutamide, a nonsteroidal antiandrogen, was administered orally to 8-week (for the 2 week study) and 6-week-old (for the 4 week study) male Crj:CD(SD) rats at dose levels of 0 mg/kg, 60 mg/kg and 200 mg/kg daily for 2 weeks or 4 weeks in order to determine whether a 2 week treatment period is sufficient for detection of drug effects on the male reproductive system. Flutamide treatment for 4 weeks resulted in decreased organ weights of the epididymides and prostate, decreased sperm counts and Leydig cell proliferation in the testes at 60 mg/kg and 200 mg/kg. Decreased sperm motility and histological lesions in the seminiferous tubules were observed at 200 mg/kg. Flutamide treatment for 2 weeks decreased organ weight of epididymides and prostate and caused Leydig cell proliferation in the testes at 60 mg/kg and 200 mg/kg. Decreased sperm counts and sperm motility, and histological lesions in seminiferous tubules were observed at 200 mg/kg. The results of this study showed that 2 weeks treatment with flutamide causes histological lesions of testes and disorders of sperm parameters similar to those observed with 4 weeks treatment, indicating that 2 weeks treatment is sufficient for detection of effects of flutamide on the male reproductive system.