Differential expression of multidrug resistance (mdr) and canalicular multispecific organic anion transporter (cMOAT) genes following extrahepatic biliary obstruction in rats

The hepatic canalicular membrane has transporters that play an important role as efflux pumps in the excretion of endogenous bile constituents or xenobiotics into bile canaliculi. To elucidate functional significance of canalicular transporters in the mechanism of cholestasis, mRNA expression levels of multidrug resistance (mdr) 1b, mdr2 and canalicular multispecific organic anion transporter (cMOAT) genes were analyzed by Southern blotting of reverse-transcribed PCR products of liver mRNA obtained from cholestatic rats that had been subjected to bile duct ligation. Both mdr1b and mdr2 mRNA expression increased after ligation. Immunohistochemical study revealed that the products of both mdr1b and mdr2 were present on the canaliculi, and that their levels increased after ligation. In contrast, cMOAT mRNA expression was not increased, but rather attenuated by ligation. The expression of canalicular transporters was differentially regulated in extrahepatic biliary obstruction, indicating the different roles are played by mdr and cMOAT in the pathogenesis of cholestasis.

Immunohistochemical study of p53 overexpression in radiation-induced colon cancers

The expressions of p53 and proliferating cell nuclear antigen (PCNA) were studied immunohistochemically from paraffin sections of 7 cases (9 lesions) of radiation-induced colon cancer and 42 cases of spontaneous colon cancer. Age distribution of radiation-induced and spontaneous colon cancer were 68.1 years (range, 56 to 77 years) and 67.4 years (range, 31 to 85 years), respectively. Among the radiation-induced colon cancers, there were 3 lesions of mucinous carcinoma (33%), a much higher than found for spontaneous mucinous cancer. Immunohistochemically, p53 protein expression was detected in 7/9 (78%) of radiation-induced cancers and in 23/42 (55%) of spontaneous colon cancers. chi 2 analysis found no significant differences between radiation-induced and spontaneous colon cancers in age distribution or p53-positive staining for frequency, histopathology, or Dukes' classification. In radiation colitis around the cancers including aberrant crypts, spotted p53 staining and abnormal and scattered PCNA-positive staining were observed. In histologically normal cells, p53 staining was almost absent and PCNA-positive staining was regularly observed in the lower half of the crypt. In radiation colitis including aberrant glands, cellular proliferation increased and spotted p53 expression was observed. This study suggests that radiation colitis and aberrant glands might possess malignant potential and deeply associate with carcinogenesis of radiation-induced colon cancer.

Acute in vivo effect of octreotide acetate, a somatostatin analogue on the cellular function of gastric mucosa in the rat

Somatostatin is known to suppress various cellular functions of the gastrointestinal tract. In the present study, octreotide acetate, a synthetic long-acting somatostatin analogue was tested for its effects on some cellular functions of gastric mucosa. Octreotide raised the gastric mucosal pH within 1 h after a single subcutaneous injection to rats at doses of 1-100 microg/kg bodyweight. Serum gastrin levels increased transiently at a dose of 10 microg/kg bodyweight but not at 100 microg/kg. Basal levels of serum gastrin were not affected, while famotidine-induced gastrin secretion was suppressed by octreotide at a single dose of 100 microg/kg. The increase in the intragastric acidity and histidine decarboxylase activity following pentagastrin treatment was significantly reduced by octreotide. These results suggested that this somatostatin analogue inhibits the function of not only the parietal cell and G cell but also the enterochromaffin-like (ECL) cell, resulting in intraluminal hypoacidity.

Comparison of two interferon alfa treatment regimens characterized by an early virological response in patients with chronic hepatitis C

OBJECTIVE

We investigated the efficacy of an interferon regimen characterized by an early virological response in patients with chronic hepatitis C and evaluated whether the patient's virological status during therapy would be useful for predicting a complete response.

METHODS

We treated 62 patients with chronic hepatitis C with 6 million units (MU) of human lymphoblastoid interferon daily for 4 wk. The serum HCV RNA was assayed at week 2 by the reverse transcription-polymerase chain reaction. HCV RNA-negative patients (group A) received 6 MU of interferon three times weekly for an additional 22 wk (total dose, 564 MU). HCV RNA-positive patients were randomly assigned to group B-1, which received the same regimen as group A, or to group B-2, which received 6 MU of interferon daily for 4 wk followed by 6 MU three times weekly for 18 wk (total dose, 660 MU).

RESULTS

Complete responses were achieved by 19 (63.3%) of 30 group A patients, compared with one (6.3%) of 16 group B-1 patients and none of 16 group B-2 patients. The virological response at week 2 and the pretreatment serum HCV RNA level were independent significant predictors of a complete response.

CONCLUSION

Patients who were still HCV RNA-positive at week 2 were unlikely to achieve a complete response after interferon therapy. An increase in the total dose of interferon failed to yield further benefit in these patients.

Glucose suppresses the activity of rat oxyntic histidine decarboxylase without affecting gastrin levels

Glucose suppressed the activity of oxyntic mucosal histidine decarboxylase within 2 h when given either intragastrically or intraperitoneally to rats fasted for 24 h. Serum levels of gastrin, secretin, glucagon, and somatostatin and oxyntic mucosal levels of gastrin, histamine, and somatostatin showed no significant changes after glucose. Glucose suppressed the aspirin-induced histidine decarboxylase activity without changing serum gastrin. It also suppressed the pentagastrin-induced histidine decarboxylase activity. Neither fructose nor mannitol had such an effect. These results suggest that glucose acts directly on the enterochromaffin-like cells in rat oxyntic mucosa to suppress histidine decarboxylase activation.

Effects of eicosanoids on lipopolysaccharide-induced ornithine decarboxylase activity and polyamine metabolism in the mouse liver

BACKGROUND/AIMS

During endotoxic shock, arachidonic acid is released from the inflammatory cell membranes and is metabolized to form eicosanoids, which modify the deleterious effects of lipopolysaccharide (LPS) on liver function. However, it is not known which prostaglandins (PGs) or leukotrienes (LTs) are produced or how they affect the LPS-treated liver. As LPS treatment elevates hepatic ornithine decarboxylase (ODC) activity and affects the polyamine levels of the mouse liver, this study was carried out to examine the effects of eicosanoids and their inhibitors on the induction of ODC activity and polyamine levels in the LPS-treated mouse liver.

METHODS

LPS in the presence or absence of other drugs was intraperitoneally administered to 6-week-old mice and the livers were then removed. The hepatic ODC activity, polyamine levels, and level of ODC mRNA were determined.

RESULTS

The levels of LPS-induced ODC activity, the putrescine (PUT) and N1-acetylspermidine (A-SPD) were reduced by the administration of PGE1. ODC activity was enhanced by the administration of corticosterone, AA-2414 (an antagonist of thromboxane (TX) A2) and TXB2, whereas the A-SPD level was reduced by corticosterone and AA-2414 treatment. The level of ODC mRNA changed in parallel with the change in ODC activity.

CONCLUSIONS

PGE1 may reduce the LPS-induced production of inflammation-accelerating cytokines and reduce the level of ODC activation. Corticosterone and AA-2414 treatment may attenuate the LPS-induced production of eicosanoids, and enhance the LPS-induced ODC activation. It is possible that the eicosanoids produced by LPS treatment inhibit ODC activation during endotoxic shock.

Brain functional activity during gait in normal subjects: a SPECT study

The purpose of this study was to evaluate changes in brain activity during voluntary walking in normal subjects using technetium-99m-hexamethyl-propyleneamine oxime single photon emission computed tomography. This study included 14 normal subjects. Statistical parametric mapping analysis revealed that the supplementary motor area, medial primary sensorimotor area, the striatum, the cerebellar vermis and the visual cortex were activated. These results suggested that the cerebral cortices controlling motor functions, visual cortex, basal ganglia and the cerebellum might be involved in the bipedal locomotor activities in humans.

Serum concentrations of soluble HLA-class I and CD8 forms in patients with viral hepatic disorders

Soluble HLA-class I and CD8 molecules were determined by sandwich ELISA in patients with viral-induced hepatic disorders. As a whole, the patients with hepatic disorders (acute hepatitis: AH; chronic hepatitis: CH; liver cirrhosis: LC; hepatocellular carcinoma: HCC) showed higher sHLA-class I and sCD8 levels than normal controls (P < 0.001). AH patients had the highest sHLA-class I levels (mean, 3513 +/- 2112 ng/ml), followed by CH (2896 +/- 1290 ng/ml), LC (2293 +/- 1266 ng/ml), and HCC (2221 +/- 1212 ng/ml) sCD8 levels wer highest in AH, followed by HCC, LC, and CH, in that order. Among histologically defined C virus-positive patients, sHLA-I levels were higher in those with chronic active hepatitis (CAH) 2A (3802 +/- 1124 ng/ml) than in those with chronic persistent hepatitis (CPH; 2200 +/- 711 ng/ml; P < 0.01), the levels then decreased as the disease progressed (CAH2B, 3564 +/- 1783 ng/ml, LC, 2376 +/- 1265 ng/ml). In contrast, sCD8 values showed little difference among the disorders. sHLA-class I levels showed a positive correlation with sCD8 values both in whole patients and in patients with AH (P < 0.01), but no correlation was shown, in any patients, with biochemical parameters such as GPT and GOT. These findings, taken together, suggest that hepatic destruction is not the only cause of sHLA-class I production, but that sHLA-class I levels, together with sCD8 levels, may reflect immunological activity in hepatic disorders.

Gastric cancer associated with overexpression of parathyroid hormone-related peptide (PTHrP) and PTH/PTHrP receptor in relation to tumor progression

Parathyroid hormone-related peptide (PTHrP) is involved in cell proliferation in both neoplastic and non-neoplastic tissues. We describe an autopsy case of gastric cancer in a patient who showed serum hypercalcemia and overexpression of PTHrP and PTH/PTHrP receptor in the metastatic tumor cells. The primary gastric tumor was poorly differentiated adenocarcinoma, and multiple metastases were present in the bone, multiple visceral organs, peritoneum, and lymph nodes. PTHrP and its mRNA were detected only in the metastatic tumor cells, but not in primary gastric tumor. PTH/PTHrP receptor was also demonstrated immunohistologically in metastatic tumor cells. This case suggests that the expression of PTHrP is related to tumor progression and the poor prognosis in tumors associated with humoral hypercalcemia.

Hepatic lobar differences in progression of chronic liver disease: correlation of asialoglycoprotein scintigraphy and hepatic functional reserve

We studied the hepatic functional reserve in the lobes of the liver in 28 patients with chronic liver disease and 13 controls using single photon emission computed tomography (SPECT) imaging with a radiolabeled asialoglycoprotein analog, Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (Tc-99m GSA). Counts of Tc-99m GSA radioactivity in the liver on SPECT images significantly correlated (P < .0001) with the serum albumin level (r = .612), log (serum cholinesterase activity) (r = .618), serum bilirubin level (r = .628), prothrombin time (r = .715), hepaplastin test (r = .637), and indocyanine green retention rate at 15 minutes (r = .771), making it possible to estimate the distribution of functional reserve in the liver based on counts. Using the intact hepatocyte theory, we estimated the number of viable hepatocytes based on the counts. With progression of hepatic functional degeneration, counts per unit hepatic volume decreased (rho = .779, P < .0001), and left lobe to right lobe ratio of this parameter increased (rho = .491, P = .0019) significantly. These findings suggest that the reduction of hepatic functional reserve per unit hepatic volume and numerical density of the hepatocytes, and the proliferation of fibrosis in patients with chronic liver disease is slower in the left lobe than in the right. We discuss a possible biological basis for these apparent lobar differences and for hepatic morphological changes seen in cirrhosis.

[Thoracic epidural anesthesia for cholecystectomy in a patient after Fontan procedure]

A 12 year-old boy who had received modified Fontan procedure was scheduled for cholecystectomy. Anesthesia was maintained with thoracic epidural anesthesia (Th8-9) and O2-N2O-sevoflurane under mechanical ventilation through the endotracheal tube. Transeshophageal echo cardiography and mixed venous oxygen saturation (SvO2) were used for hemodynamic monitoring. The combined use of epidural anesthesia and volatile anesthetics decreased central venous pressure, left ventricular end diastolic volume, left ventricular ejection fraction and SvO2. These hemodynamic problems were easily solved by infusion therapy and a low dose of dopamine. On the other hand, there were also some hemodynamic benefits such as inhibition of tachycardia and suppression of an increase in pulmonary vascular resistance due to surgical stress. Moreover, patient returned to normal spontaneous breathing with complete analgesia during the early phase after surgery. CVP and SvO2 increased to preoperative values in the recovery room. From these results, we conclude that satisfactory results can be obtained with epidural anesthesia for upper abdominal surgery after Fontan procedure.

Suppression of histidine decarboxylase activity in rat oxyntic mucosa by beraprost sodium, a prostacyclin analogue

Prostaglandins (PGs) affect various aspects of gastric functions. In the present study the orally administered PGI2 derivative beraprost sodium (TRK-100.1 micrograms per kg body weight) decreased oxyntic histidine decarboxylase activity without changing serum gastrin levels. Antral pH increased 4 hr after treatment. Beraprost also decreased the pentagastrin-induced histidine decarboxylase activity at the same dose. Serum levels of secretin, somatostatin and glucose, and oxyntic mucosal levels of histamine and somatostatin, showed no significant change after treatment with beraprost. These results suggest that the response of oxyntic histidine decarboxylase to gastrin is modified by one or more prostanoids including PGI2. This mechanism might play a role in gastric mucosal protection.

Neural control of micturition in man examined with single photon emission computed tomography using 99mTc-HMPAO

THE neural mechanisms of micturition in man were studied using single photon emission computed tomography (SPECT). The areas activated during micturition, relative to the resting state, were the upper pons, the left sensorimotor cortex, the right frontal cortex and the bilateral supplementary motor areas. Some of these regions have been established by clinical and experimental studies as the neural control centre for voiding. We confirmed the neural micturition centre in healthy men using SPECT for the first time.

Ontogenic changes in the expression of cytochrome c oxidase subunit I gene in the cerebellar cortex of the perinatal hypothyroid rat

The thyroid hormone plays a critical role in normal development of the mammalian central nervous system. This study was designed to examine the effect of perinatal hypothyroidism on ontogenic change in cytochrome c oxidase subunit I (COX I) gene expression in the rat cerebellum by using quantitative in situ hybridization histochemistry (ISH). Newborn rats were rendered hypothyroid by continuous administration of methimazole in the mothers' drinking water. The pups were then killed by decapitation on 1, 5, 10, 15, 20, and 30 days after birth (P1, P5, P10, P15, P20, and P30). Their cerebella were removed, and frozen sections were cut and processed for ISH with 35S-labeled RNA probe for COX I messenger RNA. After hybridization, emulsion autoradiography was performed. The numbers of grains within the external granule cell layer, molecular layer, and internal granule cell layer were then counted. A significant decrease in grain density was detected in the hypothyroid animal in all these areas on P5, P10, and P15. On P15, in the molecular layer, a greater hybridization signal was detected in the inner portion than in the outer portion in the euthyroid animal. No such difference was seen in the hypothyroid animal. Daily T4 treatment for 15 days restored the effect of methimazole treatment. The significant effect of perinatal hypothyroidism on COX I gene expression was not detected after P20. These results indicate that altered thyroid states affect the COX I gene expression in the cerebellar cortex during development, suggesting that the COX I gene is one of the key genes regulated by the thyroid hormone and plays an important role in the morphogenetic changes observed in the perinatal hypothyroid cerebellum.

Cerebral activation during performance of a card sorting test

The Wisconsin Card Sorting Test (WCST) is used clinically for evaluating frontal lobe function, but there is some controversy as to its specificity for detecting frontal lobe damage. To investigate the cerebral regions essential to the performance of the Card Sorting Test, we measured the regional cerebral blood flow (rCBF) in 18 normal subjects by PET under the three conditions: (i) during the Modified Card Sorting Test (MCST); (ii) during a matching-to-sample (MTS) task, based on the MCST, but with selective attention to one of three stimulus categories (colour, number or shape) as a control to cancel the effects of maintenance of sets in the MCST; (iii) under resting conditions as overall control. When rCBF during the MCST was compared with that during each MTS task separately, significant activations were observed during the MCST in the left or bilateral dorsolateral prefrontal cortex (DLPFC), bilateral inferior parietal lobes, left superior occipital gyrus and left cerebellum. Compared with all the MTS tasks inclusively, significant increase in rCBF was detected during the MCST in the bilateral DLPFC, inferior parietal lobes, striate cortex, cerebellum and left occipital cortex. These results suggest the involvement of the DLPFC and other related areas such as the inferior parietal cortex in the execution of the MCST, and may help explain why a variety of brain lesions can result in impaired performance on the Card Sorting Test.

Acute inhibitory effect of excess iodide on ornithine decarboxylase in the thyroid of propylthiouracil-treated rats

Polyamines such as putrescine, spermidine and spermine have been thought to play an important role in thyroid growth induced by goitrogens. Reduced biosynthesis of these polyamines might play a role in the antigoitrogenic effects of excess iodide. This study was designed to examine the effect of potassium iodide (KI) on ornithine decarboxylase (ODC), a rate-limiting enzyme in the biosynthesis of polyamines. Thyroidal ODC activity, protein content and mRNA were increased in rats made hypothyroid by 10 days of propylthiouracil treatment. The increase in ODC activity was suppressed after subcutaneous injection of KI (13mg/kg body weight); the apparent half-life of ODC activity after the treatment was estimated to be 19 min and the maximum suppression (90%) was seen 60 min after the treatment. On the other hand, administration of iodine-containing compounds including L-thyroxine, L-di-iodotyrosine,amiodarone, iopanoic acid and erythrosine showed no significant effect on ODC activity. The inhibitory effect of excess iodide was not reversed by pretreatment with dibutyryl cAMP and theophylline. The amount of immunoreactive ODC protein was reduced by iodide treatment (40%). However, the decrease was not as great as the decrease in ODC activity (90%). No significant change in thyroidal ODC mRNA content was seen 1 and 3 h following KI treatment. These results suggest that excess iodide reduces ODC activity in the rat thyroid gland by a post-transcriptional mechanism.

Expression of parathyroid hormone (PTH)-related peptide (PTHrP) and PTH/PTHrP receptor in giant cell tumour of tendon sheath

The giant cell tumour of tendon sheath (GCTTS) is mainly composed of mononucleated stromal cells (SC) and multinucleated giant cells (GC), so-called osteoclast-like GC. It is thought that GC are derived from SC, but their precise relationship is not fully understood. Parathyroid hormone (PTH)-related peptide (PTHrP) is now considered to be a cytokine for cell differentiation, which may stimulate osteoclast-like cell formation in haematopoietic cells. Five cases of GCTTS were evaluated immunohistochemically, using a variety of antibodies against PTHrP, PTH/PTHrP receptor, KP-1 as a histiocytic phenotypic antigen, fibronectin as a fibroblastic phenotypic antigen, and proliferating cell nuclear antigen (PCNA). In situ hybridization and immunohistochemistry revealed that in all cases both SC and GC expressed PTHrP. PTH/PTHrP receptor was observed only in histiocytic SC and GC, but not in fibroblastic SC. Almost all GC showed histiocytic features. PCNA immunoreactivity was detected only in the nuclei of SC, and not in GC. Moreover, SC with PTH/PTHrP receptor immunoreactivity were negative for PCNA. These results suggest that GC are derived from histiocytic SC expressing PTH/PTHrP receptor and losing proliferative activity in the process of transition from mononuclear to multinucleated. PTHrP produced by SC and GC may be involved in the formation of osteoclast-like cells in GCTTS by acting in an autocrine/paracrine fashion.

Functional anatomy on perception of position and motion in depth

To investigate the neural substrates for the perception of motion and of position in depth, we examined the changes in regional cerebral blood flow during positional and motion stereopsis in humans by positron emission tomography. During positional stereopsis, the right striate and peristriate cortices (areas V1/V2 and V3) and the inferior parietal lobule were significantly activated. During motion stereopsis, the right striate and peristriate cortices (V1/V2) and the ventrolateral occipital cortex (V5) were significantly activated. These results suggest that brain regions active during stereopsis may be dependent, despite their considerable overlap, on the properties of stereopsis, i.e. positional or motion stereopsis.