Overexpression of cyclin D1 and p53 associated with disease recurrence in colorectal adenocarcinoma

Multiple genetic changes occur during the evolution of normal cells into cancer cells. It has been reported that both cyclin D1 and p53 genes play major roles in oncogenesis and/or cell cycle control in various cancers. In this study, we examined the overexpression of cyclin D1 and p53 by the immunohistochemical method and investigated the correlation between expression of these antigen and prognosis in patients with colorectal adenocarcinoma. Disease-free survival was significantly lower in the patients with cyclin D1-strongly positive tumors than in those with cyclin D1-negative tumors. Similarly, disease-free survival of the patients with p53-strongly positive tumors was significantly lower than that of those with p53-negative tumors. Moreover, multivariate analysis indicated that both cyclin D1 and p53 overexpression are independent prognostic factors in patients with colorectal adenocarcinoma. In conclusion, both cyclin D1 and p53 overexpression may be useful predictors of disease recurrence in patients with colorectal adenocarcinoma.

Intrasplenic combination immunotherapy with OK-432 and interleukin-2 on liver metastasis of colorectal carcinoma in a mouse model

We investigated the inhibitory effects of intrasplenic combination therapy with OK-432 and recombinant interleukin-2 (IL-2) on liver metastasis of colorectal carcinoma. Intrasplenic administration group significantly inhibited the development of liver metastasis compared with subcutaneous administration group (p<0.05). Combination therapy significantly inhibited the development of subclinical liver metastasis compared with that in the control group. Combination therapy decreased the percentage of cells expressing CD8a, which may be a part of effective factors of combination therapy, and improved overall survival rate. These findings suggested intrasplenic combination therapy with OK-432 and IL-2 might be effective in inhibiting liver metastasis of colorectal carcinoma.

Deletion of serum lectin-reactive alpha-fetoprotein by acyclic retinoid: a potent biomarker in the chemoprevention of second primary hepatoma

A goal of cancer chemoprevention is the deletion of latent premalignant or malignant clones before they expand to a clinically detectable tumor. However, such clonal deletion has not been demonstrated in clinical studies. We have evaluated serum levels of lectin-reactive alpha-fetoprotein (AFP-L3), which suggests the presence of latent hepatoma cells, in a randomized controlled trial that used acyclic retinoid to prevent second primary hepatomas in patients who had received treatments that cured initial hepatomas. The trial involved 21 patients in each acyclic retinoid (600 mg daily) and placebo group and consisted of a 12-month period of drug administration and a subsequent follow-up period. Serum AFP-L3 was determined at entry and at the end of the 12-month treatment period using lectin-affinity electrophoresis and antibody-affinity blotting. Although neither treatment affected serum levels of total AFP, acyclic retinoid significantly reduced AFP-L3 levels after a 12-month administration (P < 0.01). Acyclic retinoid not only deleted AFP-L3 from patients who had been positive for AFP-L3 at entry but also prevented the appearance of AFP-L3 in patients who had been negative at entry (P < 0.01). In contrast, placebo significantly raised the incidence of AFP-L3-positive patients after a 12-month administration from that at entry (P < 0.05). Patients positive for AFP-L3 after a 12-month treatment had a significantly higher risk of second primary hepatomas in the subsequent follow-up period (P = 0.03). Acyclic retinoid may have deleted a clone of latent hepatoma cells producing AFP-L3 and thereby inhibited second primary hepatomas. Serum AFP-L3 may be a useful intermediate biomarker in the chemoprevention of second primary hepatomas by acyclic retinoid.

Work and workload of nursing personnel in a nursery school and two institutions for handicapped children

Work-related low back pain and cervicobrachial disorders have become increasingly common among nursing personnel with the increase in the number of social welfare institutions and workers. The aim of this study is to assess the burden on the low backs of personnel caring for children. We measured work content, working time, posture and muscular activity in 16 nursery workers in three different types of institutions for healthy and handicapped children. The working time and posture of 7 nursery teachers in a public nursery school for healthy children (A school), 7 nursing workers (4 nursery teachers and 3 nursery instructors) in a public daycare center for mentally and physically handicapped children (B center), and 2 nursery instructors in a private home for severely handicapped children (C home) were analyzed. The muscular activity of the erectores spinae muscle of three subjects was measured using a newly developed EMG monitor (portable EMG monitor, PEMM). The following results were obtained. The average length of a lesson or activity in A school was greater than that in B center and C home. The time required by care for meals was longest in C home. The arrangement and rearrangement times were longest in the classes of children aged 3-5 in A school. The time occupied for clerical work and other work was relatively longer, while recess including lunch time was approximately one hour. The most commonly observed posture was sitting on the floor in all kinds of classes, with this occurring most often in C home. Hazardous postures such as bending forward, squatting, and kneeling appeared in 11-18% (48-81 min) of a day's working time. The average muscular activity of the erectores spinae muscle of three subjects throughout a day was approximately 10% of the maximum isometric contraction (% maximum work load, %MWL), when muscular activities were measured by PEMM. The relatively high %MWL values (19-27%MWL) were obtained at a slightly bending posture and a kneeling posture, while lower (1-9%MWL) values were observed at a sitting posture. The %MWL values at a sitting posture varied according to such conditions as duration of sitting, back rest, weight on the arms, twisting of the trunk, and hip movement. The risky nature of the sitting posture are also discussed.

Propolypeptide of von Willebrand factor is a novel ligand for very late antigen-4 integrin

We have previously reported that propolypeptide of von Willebrand factor (pp-vWF) promotes melanoma cell adhesion in a beta1 integrin-dependent manner. In this report, we identified the alpha subunit of the cell adhesion receptor for pp-vWF as alpha4. Human leukemia cell lines that express alpha4beta1 integrin (very late antigen-4, VLA-4), but not cell lines which lack VLA-4, attached well to pp-vWF substrate and these adhesions were completely inhibited by anti-alpha4 integrin monoclonal antibody HP2/1. Adhesion of mouse melanoma expressing alpha4 integrin was also inhibited by anti-mouse alpha4 mAb PS/2. Furthermore, transfection of human alpha4 cDNA into alpha4(-) Chinese hamster ovary cells resulted in an acquisition of adhesive activity to pp-vWF, indicating that pp-vWF is a ligand for VLA-4 integrin. Using a recombinant fragment of pp-vWF, the cell attachment site was shown to be located within amino acid residues 376-455 of pp-vWF. A series of synthetic peptides covering this region were tested for the ability to promote cell attachment and a 15-residue peptide designated T2-15 (DCQDHSFSIVIETVQ, residues numbered 395-409) promoted VLA-4 dependent cell adhesion. The peptide was also capable of inhibiting cell adhesion to pp-vWF, suggesting that this sequence represents the cell attachment site. By affinity chromatography using peptide T2-15-Sepharose, it was found that alpha4beta1 integrin complex from extracts of surface iodinated B16 cells specifically bound to the peptide. These results strongly suggest that pp-vWF is a novel physiological ligand for VLA-4.

Vascular endothelial growth factor expression correlates with hematogenous metastasis and prognosis in colorectal carcinoma

We investigated the expression of vascular endothelial growth factor (VEGF) in 175 colorectal carcinomas by immunohistochemistry. VEGF expression was correlated with advanced TNM stage (III, IV), advanced T stage (T3, T4), vessel involvement, lymph node metastasis, and liver metastasis. With regard to the prognosis, both overall and relapse-free survival was significantly poorer, and furthermore, the hematogenous recurrences were significantly more commonly found in the patients with VEGF-positive tumors. VEGF expresion in colorectal carcinomas may have a substantial value in predicting those patients at high risk for hematogenous recurrence after surgery.

Association of atrial septal defect with Poland-Moebius syndrome: vascular disruption can be a common etiologic factor. A case report

The authors describe an association of atrial septal defect with partial symptoms of the Poland-Moebius syndrome. Both are thought to be caused by developmental disorders of the mesenchyme and ectodermal derivatives. This anomalous association can be accepted as one concept of the subclavian artery blood supply disruption sequence during embryo-genesis.

Frog experiment onboard space station Mir

Japanese tree frogs (Hyla japonica) showed unique postures and behavior during an 8-day flight to the Russian space station Mir. When floating in the air, the animals arched their back and extended their four limbs. This posture resembles that observed during jumping or parachuting of the animals on the ground. Frog sitting on a surface bent their neck backward sharply, did not fold their hind limbs completely, and pressed their abdomen against the substrate. They walked backwards in this posture. The typical posture resembles that adopted during the emetic behavior process on the ground, although the posture in space lasts much longer. The possible mechanism of induction of this unique posture in orbit is discussed. Frogs in this posture might be in an emetic state, possibly due to motion sickness. Response behavior to some stimuli was observed in orbit. Body color change in response to the background color appeared to be delayed or slowed down. Response behavior to other stimuli showed little change as long as the animal maintained contact with a substrate. Once it left the surface, the floating frog could not control its movements so as to provide coordinated motility for locomotion and orientation. Adaptation to microgravity was observed in the landing behavior after jumping. Readaptation of the frogs to the Earth environment took place within a few hours after return. Postflight histological and biochemical analysis of organs and tissues showed some changes after the 8-day spaceflight. Weakening and density loss in vertebrae was noted. The beta-adrenoreceptor activity of the gastrocnemius was natriuretic decreased. Skin collagen and liver protein synthesis were lowered. The distribution of the atrial factor-like peptides in the brain was changed.

[Otorhinolaryngological medical care by the general practitioners in rural areas]

In the present study, a survey of otorhinolaryngological medical care by the general practitioner, including the relationship between general practitioners and otorhinolaryngologists in rural areas was carried out. A questionnaire for otorhinolaryngological medical care by the general practitioners was sent to 326 hospitals with less than 100 beds where non-otorhinolaryngological doctors who had graduated from Jichi Medical School were working. Of these hospitals 164 (50.4%) responded. Most respondents said that they had about 3 or 4 patients with otorhinolaryngological disease per month. The distance between most hospitals and the nearest otorhinolaryngologists was within one hour by available transportation facilities. About 70% of the respondents were provided with simple otorhinolaryngological instruments, such as an aural speculum, a nasal speculum and a head mirror. The most frequent otorhinolaryngological diseases which they treated were vertigo, allergic rhinitis and upper respiratory infection including acute tonsillitis and pharyngolaryngitis. Only 10 to 20% of the general practitioners had otorhinolaryngological training. We found several problems in otorhinolaryngological medical care in rural areas. Patients with otorhinolaryngological disease seek otorhinolaryngological care at the nearest medical facility where general practitioners with inadequate otorhinolaryngological experience examine patients with inadequate otorhinolaryngological instruments. Therefore, a close relationship between general practitioners and otorhinolaryngologists should be developed and the quality of otorhinolaryngological medical care should be raised in rural areas.

Esophagomediastinal fistula as a complication of tuberculous mediastinal lymphadenitis

In a 44-year-old female esophagomediastinal fistula was found secondary to tuberculous mediastinal lymphadenitis. Chest computed tomography revealed amorphous air collection in the subcarinal region of the mediastinum with mediastinal lymphadenopathy. Esophagography with gastrografin confirmed esophagomediastinal fistula. The patient was treated with antituberculous therapy with rifampicin, isoniazid, pyrazinamide and ethambutol, resulting in resolution of the esophagomediastinal fistula and mediastinal lymphadenopathy.

[Selective thermocoagulation of unresectable malignant tumors using radiofrequency]

Based on our experimental findings on porcine liver, we have been conducting a clinical trial of selective hyperthermia by radiofrequency (RF) capacitive heating with laparotomy for patients with unresectable malignant tumors. In 10 patients with malignant tumors (8 carcinoma of the pancreas, 2 carcinoma of the gallbladder), laparotomy and RF heating were performed after informed consent. The local heat coagulation was produced by heating equipment using 13.56 MHz radiofrequency produced by Omron Corporation, Japan. Four 2-cm electrode needles were placed in the tumor in a square array at intervals of 2.0 cm. Hyperthermia was given for 30 min with a controlled temperature of 50 degrees C in the RF field (2 x 2 x 2 cm3). That of the surrounding area was maintained at less than 40 degrees C. The calculated volume treated by RF ranged between (2 x 2 x 2 cm3) x 1 and (2 x 2 x 2 cm3) x 6. We followed all patients by computed tomographic (CT) scan 2 weeks after coagulation. Tumor markers in the blood were assayed before and 14 days after heating. Follow-up CT scans demonstrated that after the tumor mass had been heterogeneously enhanced, it changed to a homogeneous low-density area in 6 of 10 patients. The levels of tumor markers decreased to lower than the pre-treatment values in 9 of 10 patients. In all patients, the changes in CT scans and/or decrease in the markers were confirmed. Complications such as bleeding or abscess formation were not observed. It was suggested that the selective hyperthermia was safely produced by this equipment. The encouraging results in these patients justify further clinical trials.

Primary sclerosing cholangitis associated with increased peripheral eosinophils and serum IgE

Symptoms of cholestasis, including epigastralgia, fever, and jaundice, with marked increases in peripheral eosinophils and serum IgE in a 20-year-old man are reported here. Endoscopic retrograde cholangio-pancreatography (ERCP) detected constrictions of the bile ducts, compatible with primary sclerosing cholangitis (PSC). The symptoms and blood parameters of liver dysfunction were associated with the degree of eosinophilia and high serum IgE levels. During corticosteroid therapy, all of these parameters improved, and morphologic improvements of the bile ducts were also observed. The pathogenesis of PSC may be explained, in part, by the concept of hypereosinophilic syndrome or allergic reaction.

Synergistic suppression of azoxymethane-induced foci of colonic aberrant crypts by the combination of beta-carotene and perilla oil in rats

The modulating effect of the combined dietary feeding of beta-carotene and perilla oil, which is rich in alpha-linolenic acid, on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) was investigated in male F344 rats. Rats received oral administration of beta-carotene (0, 50 or 200 mg/kg body weight/day) and fed a basal diet containing either 12% olive oil, 3% perilla oil plus 9% olive oil, or 12% perilla oil. A dose-dependent suppressive effect of perilla oil was found. The numbers of ACF were 42.0 and 18.4% of those of the 12% olive oil-fed controls in the rats fed 3% perilla oil plus 9% olive oil and 12% perilla oil, respectively. The development of ACF was also reduced significantly by the addition of dietary beta-carotene in each of the oil-fed groups (P < 0.05, respectively). The suppression by the combination of beta-carotene and perilla oil was synergistic, as the numbers of ACF were 12.9 and 8.9% of those of the 12% olive oil-fed controls in beta-carotene-treated rats fed 3% perilla oil plus 9% olive oil and 12% perilla oil, respectively. beta-carotene plus perilla oil also suppressed the numbers of silver-stained nucleolar organizer regions and the expression of ras mRNA in the colonic mucosa (cell proliferation biomarkers). Following administration of beta-carotene, a significant increase in the concentration of intact beta-carotene molecules was found in the colonic mucosa, livers, and sera. However, no accumulation of retinoids was observed in the colonic mucosa, suggesting that the inhibitory effect may not be related to the provitamin A activity. These results suggest that the combination of beta-carotene and perilla oil may be useful in the prevention of colon cancer.

Two effects of lysophosphatidic acid on Ca(2+)-movement in cultured bovine adrenal chromaffin cells

We found that lysophosphatidic acid (LPA) exerted two effects on Ca(2+)-movement in cultured bovine adrenal chromaffin cells. At concentrations of above 10(-5) M, it induced slight, but significant 45Ca2+ influx, resulting in release of a small portion of stored catecholamine. At high concentrations it also significantly increased the intracellular Ca2+ concentration in Fura-2-loaded cells. At concentrations as low as 10(-7) M, it stimulated extracellular Na(+)-dependent 45Ca2+ efflux, possibly by increasing Na+/Ca2+ exchange. The maximal efflux of Ca2+ attained with 10(-5) M LPA was inhibited by tyrosine kinase inhibitors, but augmented by a protein kinase C inhibitor. These results suggest that LPA-induced Ca2+ efflux is controlled positively and negatively by mechanisms involving tyrosine kinase and protein kinase C, respectively.

Le(b), a novel glycosphingolipid antigen of human distal colorectal cancer

The expression of the glycosphingolipid antigens was investigated in human colorectal carcinomas and adjacent normal tissues obtained by surgical operation from six patients. The glycosphingolipids, including both non-acidic glycolipid and ganglioside, were extracted from the tissue specimens and separated by two-dimensional thin-layer chromatography of silica gel. A novel neutral glycolipid antigen migrating lower than Le(a) blood group antigen was detected in the cancerous tissues of all six patients, but not in normal regions in the same patients. The structure of the glycosphingolipid was partially characterized by gas chromatography and gas chromatography/mass spectrometry of alditol acetate and negative ion fast atom bombardment mass spectrometry (FAB/MS) of the intact glycolipid, and TLC-immunostaining with monoclonal anti-Le(a), -Le(b), -sialyl Le(a), and -Le(Y) antibody, respectively. The novel neutral glycosphingolipid in colorectal cancer was identified to be the III(4)IV(2)Fuc(2)Lc(4)Cer, Le(b) antigen of the human Lewis blood system. Direct FAB/MS showed the ceramide was composed mainly of 2-hydroxy tetradecanon and C18 phytosphingosine. In such individuals, the expression of Le(b) antigen in normal tissues is absent or minimal. Based on this study, we suggest that this Le(b) antigen may be a human distal colorectal cancer-associated antigen, which will be helpful for diagnosis and treatment of distal colorectal cancer.

[Concentration and fiber size of asbestos in lungs of residents living close to the serpentinite area]

Concentrations and fiber size distribution of asbestos in the lung tissue of 16 ( 8 males and 8 females) rural residents living close to the serpentinite area (neighboring group) were analyzed by low temperature ashing-analytical transmission electron microscopy, and were compared with those of 5 (5 males) rural and 53 (34 males and 19 females) urban residents living away from the serpentinite area (reference group). The results are as follows; 1. Pulmonary asbestos fibers were found in all rural residents. The types of asbestos fibers were chrysotile, amosite, crocidolite, actinolite, and tremolite. These findings were very similar to results for urban residents. 2. In males, the geometric mean concentration of actinolite-tremolite in the neighboring group (1.78 x 10(6) fibers/g dry lung) was significantly higher than those in the reference groups (rural: 0.32 x 10(6), urban: 0.31 x 10(6), p < 0.01). In females also, the geometric mean concentration of actinolite-tremolite in the neighboring group (0.59 x 10(6)) was significantly higher than that in the reference group (urban: 0.16 x 10(6), p < 0.05). There were no significant differences in the actinolite-tremolite concentrations between males and females in the neighboring group. 3. The serpentinite in this area have contained not only chrysotile but also both actinolite and tremolite. There was no significant relationship between actinolite-tremolite concentration and occupational history in the neighboring group. It is possible that actinolite and tremolite are liberated from the serpentinite to the atmosphere and inhaled by the residents near the serpentinite area which increases pulmonary actinolite-tremolite concentration. 4. The difference in the geometric mean concentration of chrysotile between the neighboring and the reference group was not statistically significant for both sexes, possibly due to the poor durability of chrysotile in the lung tissue. 5. There were no significant differences in the geometric mean of fiber length and diameter of actinolite-tremolite between the neighboring and the reference group.

Prevention of second primary tumors by an acyclic retinoid, polyprenoic acid, in patients with hepatocellular carcinoma. Hepatoma Prevention Study Group

BACKGROUND

In patients with hepatocellular carcinoma (hepatoma), the rate of recurrent and second primary hepatomas is high despite surgical resection and percutaneous ethanol-injection therapy. We developed an acyclic retinoid, polyprenoic acid, that inhibits hepatocarcinogenesis in the laboratory and induces differentiation and apoptosis in cell lines derived from human hepatoma. In a randomized, controlled study, we tested whether the compound reduced the incidence of recurrent and second primary hepatomas after curative treatment.

METHODS

We prospectively studied 89 patients who were free of disease after surgical resection of a primary hepatoma or the percutaneous injection of ethanol. We randomly assigned the patients to receive either polyprenoic acid (600 mg daily) or placebo for 12 months. We studied the remnant liver by ultrasonography every three months after randomization. The primary end point of the study was the appearance of a histologically confirmed recurrent or new hepatoma.

RESULTS

Treatment with polyprenoic acid significantly reduced the incidence of recurrent or new hepatomas. After a median follow-up of 38 months, 12 patients in the polyprenoic acid group (27 percent) had recurrent or new hepatomas as compared with 22 patients in the placebo group (49 percent, P = 0.04). The most striking difference was in the groups that had second primary hepatomas--7 in the group receiving polyprenoic acid as compared with 20 in the placebo group (P = 0.04 by the log-rank test). Cox proportional-hazards analysis demonstrated that as an independent factor, polyprenoic acid reduced the occurrence of second primary hepatomas (adjusted relative risk, 0.31; 95 percent confidence interval, 0.12 to 0.78).

CONCLUSIONS

Oral polyprenoic acid prevents second primary hepatomas after surgical resection of the original tumor or the percutaneous injection of ethanol.

Suppressing effect of perilla oil on azoxymethane-induced foci of colonic aberrant crypts in rats

We have investigated the modulatory effect of dietary perilla oil which is rich in the n-3 polyunsaturated fatty acid, alpha-linolenic acid, on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) in male F344 rats. Animals were given three weekly subcutaneous injections of AOM (15 mg/kg body weight) to induce ACE. The rats were fed a basal diet containing either 12% olive oil, 12% safflower oil, 12% perilla oil, 6% perilla oil plus 6% olive oil, or 3% perilla oil plus 9% olive oil for 5 weeks, starting 1 week before the first dosing of AOM. All rats were sacrificed 2 weeks after the last AOM injection. The amount of food consumed and body weight gain were identical among every dietary group. The frequency of ACF was significantly lower in the rats fed 12% perilla oil than in those fed 12% olive oil or 12% safflower oil (P < 0.01 and P < 0.05, respectively). The suppressive effect of perilla oil was dose-dependent, as the number of ACF was 20.7, 40.7 and 47.4% of those of the 12% olive oil-fed controls in rats fed 12% perilla oil, 6% perilla oil plus 6% olive oil and 3% perilla oil plus 9% olive oil, respectively. Perilla oil significantly reduced ras expression as well as the AgNORs count (cell proliferation biomarkers) in the colonic mucosa, as compared with olive oil or safflower oil (P < 0.01, respectively). Marked increases in n-3 polyunsaturated fatty acids in membrane phospholipid fractions and decreased PGE2 levels were observed in colonic mucosa of perilla oil-fed rats. These results suggest that perilla oil, even in small amounts, suppresses the development of aberrant crypt foci, and is therefore a possible preventive agent in the early stage of colon carcinogenesis.

Oral supplementation with branched-chain amino acids improves transthyretin turnover in rats with carbon tetrachloride-induced liver cirrhosis

The hypothesis that dietary branched-chain amino acid (BCAA) supplementation improves the impaired protein turnover in male Donryu rats with carbon tetrachloride-induced liver cirrhosis was tested. We supplemented cirrhotic rats orally for 2 wk with BCAA solution [26.67 mg BCAA/(100 g body weight . d)], a conventional amino acid mixture [4.25 mg BCAA/(100 g body weight . d)] or saline and fed these three groups the AIN76 basal diet to have similar intakes of total energy and total nitrogen. Normal rats without liver cirrhosis were fed the basal diet similar to the above (noncirrhotic controls). After supplementation, rats were fed intravenous transthyretin (thyroxine-binding prealbumin) doubly labeled with 125I-tyramine-cellobiose and 131I. Kinetic indices including production rate of transthyretin were analyzed from plasma transthyretin disappearance curves. Tissue sites of transthyretin degradation were assayed using a trapped ligand technique by measuring 125I-tyramine-cellobiose levels. The production rate of transthyretin was significantly lower in cirrhotic rats supplemented with saline (mean 25.46 X 10(-3) . h(-1)) compared with noncirrhotic controls (45.08 X 10(-3) . h(-1)) (P < 0.05). This was corrected by supplementing cirrhotic rats with BCAA (37.05 X 10(-3) . h(-1), P < 0.05) but not with conventional amino acid mixture (22.49 X 10(-3) . h(-1)). The accelerated degradation of transthyretin in muscles of cirrhotic rats was improved by BCAA (P < 0.05). In conclusion, dietary supplementation with BCAA improves the impaired transthyretin turnover in rats with liver cirrhosis.

Impaired synthesis of retinol-binding protein and transthyretin in rat liver with bile duct obstruction

To gain further insight into the protein metabolism in bile duct-obstruction, we examined the synthesis of retinol-binding protein (RBP) and transthyretin (TTR) in rats with common bile duct-ligation. In these rats, liver and plasma levels of RBP and TTR decreased markedly, whereas liver retinoid contents remained unchanged. Although there appeared no decrease in the total amount of RBP or TTR mRNA expressed in the liver, the subcellular distribution of these mRNAs changed from the membrane-bound polysome fraction to the membrane-unbound polysome fraction. This abnormal distribution recovered rapidly after biliary drainage, resulting in the subsequent recovery of the plasma RBP and TTR levels. These observations suggest that cholestasis inhibits the synthesis and secretion of RBP and TTR by disrupting the binding of their mRNAs to membrane-bound polysomes. Plasma levels of RBP and TTR might be sensitive indicators of the recovery of protein synthesis after biliary drainage in patients with obstructive biliary disorders.

Retinoic acid-stimulated liver stellate cells suppress the production of albumin from parenchymal cells via TGF-beta

We studied a cell-cell interaction via transforming growth factor-beta (TGF-beta ) between liver stellate cells (SCs) and parenchymal cells (PCs) using co-cultures of rat primary SCs and PCs. Both TGF-beta added exogenously to the culture medium, and TGF-beta produced endogenously from SCs after stimulation with retinoic acid (RA), suppressed the production and secretion of albumin from PCs. This effect occurred at the translational level, but not at the transcriptional level; TGF-beta, as well as SC culture medium conditioned by RA, did not affect the albumin mRNA levels, but decreased the biosynthesis of [35-S]methionine-labeled albumin without altering its post-translational degradation rate. These results suggest that TGF-beta generated from SCs facilitates the development of liver cirrhosis not only by inducing the production of fibrotic components from SCs, but also by impairing the function of the surrounding PCs.

Peptide YY-induced alteration of colonic electrolyte transport in the rat

The effect of peptide YY (PYY) on active electrolyte transport in rat colon was studied under short-circuited conditions. PYY (10(-6) M) decreased the basal short-circuit current (Isc) in both the distal and proximal segments of the colon. The decrease in Isc induced by PYY in the distal colon was about 3 times larger than that in the proximal colon. The response to PYY was inhibited by diphenylamine 2-carboxylate, a specific blocker of the Cl-channel, but not by amiloride, a Na-channel blocker. Unidirectional flux measurements in the distal colon revealed that PYY increased the net Na and Cl absorption and decreased the serosal-to-mucosal Cl flux. PYY inhibited the neurally mediated secretory response to electrical field stimulation in a concentration-dependent manner. PYY was also shown to reduce the direct action of the cholinergic agonist bethanechol on the epithelium. These results suggest that PYY inhibits electrogenic Cl secretion and stimulates electroneutral NaCl absorption via both presynaptic and postsynaptic sites in the distal colon.

Suppression of mouse skin papilloma by canthaxanthin and beta-carotene in vivo: possibility of the regression of tumorigenesis by carotenoids without conversion to retinoic acid

Using mouse skin papilloma as a model system, we examined whether the antitumorigenic activity of carotenoids was related to their provitamin A activity. Oral administration of canthaxanthin (CX) or beta-carotene at 200 mg/kg/day for 14 days significantly reduced the cumulative size of papillomas induced on the skin by 9,10-dimethyl-1,2-benzanthracene (p < 0.05), after the accumulation of these carotenoids in the tumors. The levels of a protooncogene, c-myc, were simultaneously suppressed in papillomas in carotenoid-treated mice. Because CX cannot be converted metabolically to retinoids, these results suggested that CX directly inhibited the growth of papillomas. Neither the accumulation of retinoids nor the expression of a retinoic acid-inducible gene, retinoic acid receptor-beta, was found in papillomas of CX- and beta-carotene-treated mice, suggesting that, like CX, beta-carotene might exert the tumor-suppressing effect without being converted to retinoids. Thus a certain antitumorigenic activity of carotenoids appears not necessarily to require their provitamin A activity.