Expression of intercellular adhesion molecule-1 on human thyroid cells from patients with autoimmune thyroid disease: study of thyroid xenografts in nude and severe combined immunodeficient mice and treatment with FK-506

It has been suggested that intercellular adhesion molecule-1 (ICAM-1) may play an important role in the initiation, localization, and perpetuation of autoimmune thyroid diseases (AITD). In an effort to clarify its role, we have investigated the expression of ICAM-1 on thyroid epithelial cells (TEC) of patients with AITD, patients with nontoxic goiter (NTG), and normal subjects (PN) by flow cytometric analysis under basal conditions and after modulation with cytokines, before and after 8 weeks of thyroid tissue xenotransplantation in nude athymic mice (which lyses all passenger lymphocytes), and in severe combined immunodeficient (SCID) mice where these cells survive. Before xenografting, ICAM-1 was expressed on 56% of TEC from Hashimoto's thyroiditis (n = 5), 54% of Graves' disease (n = 6), 15% of NTG (n = 5), and 12% of PN TEC. After the xenografts had been 8 weeks in nude mice, ICAM-1 expression decreased markedly in AITD TEC [from 56% to 10% in Hashimoto's thyroiditis (P < 0.001) and from 54% to 8% in Graves' disease (P < 0.01)], but did not change significantly in NTG or PN. After the xenografts had been 8 weeks in SCID mice, the expression of ICAM-1 was significantly higher on TEC of AITD compared with the same tissue in nude mice. When the SCID mice engrafted with AITD tissue were treated with the anti-CD4+ T (helper) cell agent FK-506, the expression of ICAM-1 was reduced significantly compared with that in the original tissue or that in nontreated mice engrafted with the same tissue. The proportion of TEC that were ICAM-1 positive was up-regulated in all cases by certain cytokines (e.g. interferon-gamma and tumor necrosis factor-alpha applied alone or in combination). We also detected the presence of ICAM-1 in AITD frozen tissues using an immunohistochemical technique. These data suggest a role for ICAM-1 in human AITD. However, the expression of ICAM-1 appears to be a secondary phenomenon in response to the immune assault, rather than a primary event. Our results support the idea that TEC may act as passive captives to immunological events in human AITD.

Up-regulation of protein serine/threonine phosphatase type 2C during 1 alpha,25-dihydroxyvitamin D3-induced monocytic differentiation of leukemic HL-60 cells

Treatment with 20 nM 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) caused a progressive increase in the activity of Mg(2+)-dependent protein serine/threonine phosphatase type 2C (PP2C) in subcellular fractions of HL-60 cells, whereas PP2C activity was relatively constant throughout all-trans retinoic acid-induced (1 microM) granulocytic differentiation. The increase in PP2C activity appeared to parallel the 1,25(OH)2D3-induced phenotypic and functional changes in HL-60 cells. Immunoblot and Northern blot analysis indicated that the increase in PP2C activity corresponded to the increased expression of PP2C protein, which was preceded by an increase in the level of mRNA for PP2C beta. No mRNA for PP2C alpha was detected in resting or 1,25(OH)2D3-stimulated HL-60 cells. These results suggest that the increased expression of PP2C is related with the 1,25(OH)2D3-induced monocytic differentiation of HL-60 cells.

[Pulmonary tuberculosis with systemic lymph node swelling]

A 31-year-old woman was admitted to our hospital because of cervical and axillar lymph node swelling. A chest X-ray film showed many nodular shadows and a cavity in the left upper lung field. The tuberculin test was positive. Transbronchial lung biopsy and cervical lymph node biopsy were done. Examination of the biopsy specimens revealed epithelial granulomas with caseous necrosis. Thus, pulmonary tuberculosis with systemic lymph node swelling was diagnosed. Examinations during the patient's hospital stay showed that she was not an immunocompromised host. Pulmonary tuberculosis with systemic lymph node swelling occurs only rarely in a non-immunocompromised host.

Effect of diabetic sera on the conversion of eicosapentaenoic acid (EPA) to prostaglandin I3 by cultured bovine aortic endothelial cells

The effects of sera from diabetic patients and healthy donors on the synthesis of prostaglandin I2 (PGI2) and PGI3 in vitro were studied in confluent bovine aortic endothelial cells cultured with EPA. The products 6-keto-PGF1 alpha and delta 17-6-keto-PGF1 alpha were measured by GC/SIM as markers of PGI2 and PGI3 formation in growth medium after 60 min of incubation. PGI2 and PGI3 synthesis with 10% diabetic sera were less than with sera from healthy donors (p < 0.05). However, the total prostacyclin production (PGI2 and PGI3) in the cell cultures incubated with 10 microM EPA and 10% diabetic sera approximated that of the cultures incubated with the sera of healthy donors without EPA. These results suggest that the diabetic sera inhibits PGI2 and PGI3 synthesis in the cultured endothelial cells, and that EPA intake may reduce the complications of diabetes mellitus, such as microangiopathy and vaso-occlusive diseases, and enhances the production of PGI3 which seems to exert a strong anti-aggregatory effect.

Effects of diet on cholecystokinin-stimulated amylase secretion by pancreatic Acini and amylase mRNA levels in rat pancreas

To investigate the mechanisms by which dietary compositions regulate the exocrine pancreas, we examined the effects of no-fat diet (NFD) and high-fat diet (HFD) on cholecystokinin (CCK)-stimulated amylase secretion from rat pancreatic acini. Rats were maintained for 4 weeks on NFD or HFD, which contained 0 or 45% fat and 58 or 29% carbohydrates, respectively. Pancreatic acini were isolated and stimulated by graded doses of CCK for 30 min. Maximal CCK-stimulated amylase secretion by pancreatic acini from rats on NFD (23.1 +/- 4.3 U/mg protein at 10(-10) M) was significantly higher than that of HFD (5.5 +/- 1.6 U/mg protein at 10(-10) M). In contrast, expressed as a percentage of the initial content, maximal CCK-stimulated amylase secretion by pancreatic acini from rats on NFD (15.0 +/- 0.8%) tended to be lower than that from rats on HFD (28.1 +/- 3.5%). To study further the effects of the diets on amylase mRNA levels, another group of rats was maintained on the respective diets for 4 weeks, sacrificed, and total pancreatic RNA isolated. Amylase mRNA levels in rats on NFD were 2.5 times higher than in rats on HFD. The results suggest that alterations in CCK-stimulated amylase secretion by pancreatic acini, as well as modifications in pancreatic amylase expression, may be involved in the mechanisms by which the exocrine pancreas adapts to diet.

Central projections of the antennal cold receptor neurons and hygroreceptor neurons of the cockroach Periplaneta americana

The central projections of the cold receptor axons were examined by filling two types of cold receptive sensilla with cobalt lysine--a cold and hygroreceptive (C/H) sensillum and a cold receptive and olfactory (C/O) sensillum--on the antennae of the cockroach, Periplaneta americana L. When the dye filled a single C/H sensillum, four axons were stained. Three of these axons terminate in the ipsilateral antennal lobe, while the other branches in the ipsilateral dorsal lobe. One of the branches passed through the tritocerebrum to terminate in the suboesophageal ganglion, while the other branches end in the lobe. When a single C/O sensillum is dye filled, all axons of the four receptor neurons terminate exclusively in the ipsilateral antennal lobe. One axon from the C/H sensillum and one axon from the C/O sensillum terminate in a particular glomerulus in the ventroposterior region of the antennal lobe. Each of these axons also has a tuft in separate glomeruli situated just dorsal to the glomerulus in which both axons terminate. This set of three glomeruli have indistinct boundaries and appear to form a complex of glomeruli similar to the macroglomerular complex of male moths. Assuming modality-specific convergence of antennal afferents, these axons appear to belong to the cold receptor neurons, and the set of glomeruli appear to function in cold reception. Two other neurons stained from C/H sensilla always terminate in the glom-eruli distinct from the set of glomeruli mentioned earlier. These neurons are assigned to the pair of hygroreceptor neurons, and their glomeruli are thought to function in hygroreception.

[A case of pineoblastoma successfully treated with surgery, combined chemotherapy of cisplatin and etoposide, and radiotherapy]

A 5-year-old girl was admitted to another clinic because of vomiting and convulsions. She was brought to our clinic after a ventriculoperitoneal shunt was inserted. CT scan on admission in our clinic showed a tumor in the pineal region with tumoral hemorrhage. Tumor markers such as HCG, AFP, CEA, P-LAP were within normal range. A biopsy of the tumor was performed and the histological diagnosis was pineoblastoma. Her recovery was excellent and disseminated metastasis was not recognized. A subtotal removal of the tumor was performed through the occipital transtentorial approach. She had no neurological deficits after surgery. She then received two 5-day cycles of chemotherapy, consisting of intravenous administration of 20 mg/m2/day cisplatin and 60 mg/m2/day etoposide, and craniospinal radiotherapy. After these therapies, the tumor responded and disappeared completely. Follow-up radiographic investigations also demonstrated no abnormal evidence except for brain atrophy. She is attending a primary school without any problems. Pineoblastoma is quite rare and remarkably malignant. Hence, aggressive therapies including surgery, radiotherapy and chemotherapy is indicated for this tumor.

WS75624 A and B, new endothelin converting enzyme inhibitors isolated from Saccharothrix sp. No. 75624. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities

Novel endothelin converting enzyme (ECE) inhibitors, WS75624 A and B, have been isolated from the fermentation broth of Saccharothrix sp. No. 75624. These inhibitors were purified from an acetone extract of whole culture broth followed by HP-20 column chromatography, silica gel column chromatography and HPLC. WS75624 A and B showed highly potent ECE inhibitory activity, and both had IC50 values of 0.03 microgram/ml. WS75624 A and B also showed other metalloprotease (collagenase and neutral endopeptidase) inhibitory activity with IC50 values of 1 microgram/ml. Since large amount of WS75624 B was isolated, we tried in vivo evaluation using WS75624 B. WS75624 B inhibited big endothelin-induced pressor effect when administered to SD rat intravenously with big ET-1.

Endovascular treatment of an extracranial internal carotid artery aneurysm at the skull base with mechanically detachable coils--case report

A 45-year-old male experienced a transient ischemic attack manifesting as left blurred vision and right hemiparesis. Angiography demonstrated an extracranial internal carotid artery aneurysm at the entrance of the carotid canal just above the C-1 vertebral arch. Intraluminal occlusion of the aneurysm was achieved with mechanically detachable coils under local anesthesia, and the carotid flow was preserved. There was no complication during or following the procedure. Treatment of aneurysms using detachable coils is an important alternative to surgical treatment when surgical access to the lesion is difficult.

Hematopoietic stem cells found in lineage-positive subsets in the bone marrow of 5-fluorouracil-treated mice

It is known that treatment of mice with 5-fluorouracil (5-FU, 150 mg/kg) confers radioprotection. To investigate this effect, we performed bone marrow transplantation (BMT) using C57BL/6-Ly5 congenic mice treated with 5-FU five days prior to experiments. The mononuclear cells (MNC) in 5-FU-treated bone marrow (BM) were 10 times more radioprotective than those in untreated BM. Moreover, the number of BM MNC expressing c-kit on their surface from 5-FU-treated mice was markedly decreased relative to those from untreated controls. These results showed that the surface characteristics of cells that contributed to this radio-protective effect differ from those of stem cells as reported recently. BM MNC of mice treated with 5-FU were separated on the basis of expression of the lineage-specific antigens (Lin), c-kit, and Ly6A/E. When injected into lethally irradiated mice, 1,000 Lin+ and Lin-c-kit+Ly6A/E+ cells showed radioprotective effects such that 100% and 60% survived, respectively. Flow cytometric analysis 165 days after BMT showed that 88.8% and 65.1% of peripheral blood (PB) in mice transplanted with Lin+ and Lin-c-kit+Ly6A/E+ was derived from donor mice, respectively. After six months, donor-derived Lin-c-kit+Ly6A/E+ cells which showed radioprotective effects on a secondary irradiated host were detected from mice transplanted with Lin+ cells from 5-FU-treated mice. Taken together, these findings demonstrated that stem cells expressing Lin+ present in the BM of mice treated with 5-FU other than Lin-c-kit+Ly6A/E+ cells and these Lin+ cells play an important role in the recovery of myeloablative mice.

[Anterior nerve roots enhancement on MRI in a case of Guillain-Barré syndrome]

A 4-year-old girl with Guillain-Barré syndrome (GBS) showed the abnormal enhancement on MRI in the anterior nerve roots corresponding to the region of her muscle weakness on the 26th day of illness. The enhancement on MRI almost disappeared on the 89th day of illness, when her symptoms had more improved. We think that enhanced spinal MRI is useful to reveal the involved nerve roots and the degree of the illness in GBS.

A case of iatrogenic growth retardation induced by a corticosteroid-containing anti-allergic drug

A nine-year old boy developed reduced growth velocity at the age of seven. The peak plasma growth hormone (GH) response to 3,4-dihydroxyphenylalanine, GH-releasing factor and insulin was 10.2, 8.1 and 7.6 micrograms/l, respectively, suggesting that the GH reserve was slightly reduced. Serum cortisol was undetectable and urinary excretion of 17-hydroxycorticosteroid was low (0.22-0.31 mg/day), but there were no physical or biochemical signs of adrenocortical insufficiency. He had taken an anti-allergic drug containing 0.25 mg of betamethasone and 2 mg of d-chlorpheniramine maleate per tablet for about 2 years to treat allergic rhinitis. Catch-up growth occurred when this drug was stopped. The present case suggests that daily administration of 0.25 mg of betamethasone can induce growth retardation and that ingestion of corticosteroid-containing preparations needs to be excluded in children who develop short stature without other symptoms.

Homing of 51Cr-labeled human peripheral lymphocytes to Graves' thyroid tissue xenografted into SCID mice

We have recently described a NUDE/SCID mouse model that has been useful for the study of human thyroid autoimmunity in in vivo conditions. The reappearance of lymphocytic infiltration in Graves' thyroid tissue and a humoral response in SCID mice (rexenografted with normalized thyroid tissues from NUDE mice) was detected only if autologous Graves' human peripheral lymphocytes (PBMC) were engrafted into the same animals. Therefore it was presumed that some autoreactive PBMC directed themselves to the thyroid. However, there was previously no direct evidence regarding the trafficking of the engrafted PBMC to the target tissue. To elucidate this point we have studied the migration of 51Cr-labeled PBMC in SCID mice. Human thyroid tissue from six Graves' disease (GD) patients and six patients with nontoxic nodular goiter were initially xenografted into NUDE mice for 8 weeks. The same tissues were retrieved and rexenografted into several "virgin" SCID mice, i.e., no previous xenografts. Autologous PBMC were isolated from blood of the same patients obtained at the time of the tissue rexenograftment and labeled with radioactive 51Cr. Twenty million labeled PBMC were engrafted into each SCID mouse. The distribution of labeled lymphocytes into mouse organs and trafficking into Graves' and normal xenografts was measured. A significant amount of radioactivity in Graves' xenografts was detected after 1 week with the peak of radioactivity at 2-3 weeks. This radioactivity was significantly higher than radioactivity in surrounding tissues (skin, muscle). In contrast, homing of autologous lymphocytes into normal paranodular thyroid tissue was very minimal; the radioactivity of GD thyroid xenografts with engrafted autologous lymphocytes was significantly higher than that of normal tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of monoclonal antibody against CD45RB on peripheral blood mononuclear cell proliferation and on HLA-DR and adhesion molecule expression on thyrocytes of patients with autoimmune thyroid disease

To evaluate the role of CD45 (especially that of the ectodomain region B) on immunocyte-thyrocyte signaling in patients with autoimmune thyroid disease (AITD), we have examined the in vitro and in vivo effects of a monoclonal antibody (mAb) against with CD45RB, termed MT3. MT3 was added to cultured peripheral blood mononuclear cells (PBMC) from patients with AITD and was additionally injected into severe combined immunodeficient (SCID) mice to which Graves' thyroid cells and intrathyroidal lymphocytes were engrafted. MT3 stimulated proliferation of PBMC when cultured for 2 to 3 days in patients with Hashimoto's thyroiditis (HT) and Graves' disease (GD) and in normal controls (NC). However, when cultured for 7 days, the stimulation index [SI: counts per minute (cpm) with mAb/cpm without mAb] was lowered by MT3 in NC and GD patients. However, the mean SI was not lowered in patients with HT. In SCID mice, the concentrations of human immunoglobulin G, antithyroglobulin and antithyroperoxidase antibodies in sera were not significantly changed by injecting MT3. The expression of human leukocyte antigen (HLA)-DR and intercellular adhesion molecule (ICAM)-1 on engrafted human thyrocytes decreased after the tissues were engrafted into the control mice to which vehicle alone was injected. However, in the mice injected with MT3, HLA-DR and ICAM-1 expression remained high or up-regulated by the injection.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of the novel calcium antagonist AE0047 on responses of isolated dog blood vessels to vasoconstricting agents and to nerve stimulation]

The effect of AE0047 on contractile responses to high K+ and agonists and to perivascular nerve stimulation was investigated using isolated dog cerebral, coronary and mesenteric arteries and mesenteric veins. AE0047 inhibited concentration-dependent contractions induced by KCl, norepinephrine, prostaglandin (PG) F2 alpha and serotonin. The inhibition of contractions caused by PGF2 alpha and serotonin was greater in cerebral arteries than in mesenteric arteries. The inhibitory effect of AE0047 on norepinephrine-induced mesenteric arterial contraction persisted for 24 hr or longer even though the strips were repeatedly washed. Greater inhibition was obtained in the arteries contracted with K+ than in those contracted with agonists. AE0047 reduced Ca(2+)-induced contraction in K(+)-depolarized mesenteric artery strips to a greater extent than those in PGF2 alpha-stimulated strips. The relaxation induced by transmural electrical stimulation in coronary arteries treated with phenotolamine was reduced by AE0047, whereas the norepinephrine-induced relaxation was unaffected. In cerebral arteries treated with superoxide dismutase, AE0047 reduced nicotine-induced relaxation but not NO-induced relaxation. These findings suggest that AE0047 selectively inhibits vasocontractions via voltage-dependent Ca channels and preferentially inhibits cerebroarterial contraction, these actions being long-lasting. AE0047 appears to reduce the release of neurotransmitter from adrenergic and nitroxidergic nerve terminals in blood vessels.

Protective effects of a glucocorticoid on downregulation of pulmonary beta 2-adrenergic receptors in vivo

We investigated the in vivo effects of a glucocorticoid on beta-agonist-induced downregulation of beta 1- and beta 2-adrenergic receptors (determined by [125I]iodocyanopindolol binding), mRNA expression (assessed by Northern blotting), and gene transcription (using nuclear run-on assays) in rat lung. Dexamethasone (Dex) (0.2 mg/kg/d, days 1-8) increased beta 1- and beta 2-receptor numbers by 70 and 69% above control, respectively, but did not change their mRNA expression. Isoproterenol (Iso) (0.96 mg/kg/d, days 2-8) decreased beta 1- and beta 2-receptor numbers by 48 and 51%, respectively, and also reduced mRNA expression by 69 and 57%, respectively. The combination of Dex and Iso resulted in no net change in beta 2-receptor number and its mRNA expression, although there was a significant reduction in beta 1-receptor number and mRNA expression. The mapping of beta 1- and beta 2-receptors by receptor autoradiography confirmed these findings over alveoli, epithelium, endothelium, and airway and vascular smooth muscle. We also measured the activation of the transcription factor, cyclic AMP response element binding protein (CREB) using an electrophoretic mobility shift assay. CREB-like DNA-binding activity was decreased after Iso treatment but this decrease was prevented after treatment with Dex. Nuclear run-on assays revealed that the transcription rate of the beta 1-receptor gene did not alter after Dex treatment, but was reduced after Iso treatment. The transcription rate of the beta 2-receptor gene was increased after Dex treatment by approximately twofold, but there was no change after Iso treatment. We conclude that glucocorticoids can prevent homologous downregulation of beta 2-receptor number and mRNA expression at the transcriptional level without affecting beta 1-receptors and that the transcription factor CREB may be involved in this phenomenon. Such an effect may have clinical implications for preventing the development of tolerance to beta 2-agonists in asthmatic patients treated with beta-agonist bronchodilators.

Thyroid stimulating antibody in sera of Graves' ophthalmopathy patients as a possible marker for predicting the efficacy of methylprednisolone pulse therapy

Nine patients with Graves' ophthalmopathy (GO) were treated with intravenous methylprednisolone pulse therapy and followed up by ophthalmological assessment, magnetic resonance imaging, and thyroid-associated autoantibody (thyroid stimulating antibody (TSAb), TSH binding inhibitor immunoglobulins (TBII), and anti-eye muscle antibody (EMAb)). Ophthalmological assessment was performed by the ophthalmopathy index (OI) which was made on the basis of the system recommended by the American Thyroid Association Committee. EMAb was expressed as the ratio of density of the 64 kDa band of eye muscle membrane to that of 92 kDa non-specific band found with all normal sera when assessed by western blotting. Five patients with mild ophthalmopathy (OI < 4) did not show progressive improvement in OI. Three of 4 patients with severe eye disease (OI > 4) showed a progressive and distinct improvement in OI. These 3 patients had high TSAb levels before methylprednisolone pulse therapy. One patient with severe ophthalmopathy did not respond to this pulse therapy; this patient's TSAb was negative. A significant positive correlation was observed between the activity of TSAb before treatment and the improvement in OI (delta OI) (r = 0.86, P < 0.01, n = 9). The relationship between delta OI and EMAb did not reach significance. These results suggest that TSAb in sera of GO patients can be a useful marker for predicting the efficacy of methylprednisolone pulse therapy.

Galactosylated proteins are recognized by the liver according to the surface density of galactose moieties

The recognition of 111In-labeled galactosylated superoxide dismutase (Gal-SOD) and galactosylated bovine serum albumin (Gal-BSA) by the liver was investigated in mice after intravenous injection. 111In-labeled galactosylated proteins were recovered in the liver by amounts that were highly dependent on the degree of galactose modification and the administered dose. The distribution patterns were analyzed based on a physiological pharmacokinetic model including an uptake process with Michaelis-Menten kinetics in the liver and hepatic plasma flow. The Michaelis constant of hepatic uptake of 111In-Gal-SOD was observed to inversely correlate with the number of galactose residues, without a significant change in maximum rate of uptake or extrahepatic clearance. This relation could be applied to 111In-Gal-BSA and other galactosylated proteins by using the surface density of galactose residues as a degree of modification, suggesting galactose density controls ligand recognition by the asialoglycoprotein receptor. The analysis also indicated that increasing galactose density higher than 1.0 x 10(-3) molecules/A2 did not affect the distribution of galactosylated proteins due to limitation by the hepatic plasma flow rate. In conclusion, efficient delivery of proteins modified with galactose to the liver will be achieved by controlling both the galactose density on the protein surface and the administered dose.

[Low-dose cytarabine ocfosfate therapy in an elderly acute myelogenous leukemia]

A 71-year-old man was admitted for severe anemia. Bone marrow puncture revealed 48% of blast cells. A diagnosis of acute myelogenous leukemia (AML-M 4) was made. As the patient was old, we administered 300mg of cytarabine ocfosfate (SPAC) for 21 days. Blast cells in bone marrow decreased 5.6%, and SPAC was considered effective. We treated him with the same dose of SPAC for 14 days after a 21-day interval from the end of the first treatment. Although leukemic cells were still seen in bone marrow after two treatments, we considered him in partial remission, and he was discharged. After discharge, the hematological findings remain almost normal with intermittent treatment of 150 mg of SPAC for over one year. Thus, cytarabine ocfosfate might be useful in elderly AML patients.

Bioactivity of thyrotropin (TSH) in patients with central hypothyroidism: comparison between in vivo 3,5,3'-triiodothyronine response to TSH and in vitro bioactivity of TSH

To investigate the cause(s) of central hypothyroidism with normal or elevated TSH concentrations, we evaluated the bioactivity of serum TSH as well as pituitary and thyroid function. Seven hypothyroid patients had documented deficiencies of anterior pituitary hormones other than TSH. Basal TSH concentrations ranged from 2.2-14.8 microU/mL. Six patients had low T4 and free T4 concentrations; the remaining patient had a low free T4 and a low normal T4 level with an elevated TSH concentration of 14.4 microU/mL. The mean increment in TSH 30, 60, and 90 min after TRH administration (mean delta TSH) in these patients was 13.5 +/- 9.1 microU/mL (mean +/- SD), which was not significantly different from the value in controls (9.2 +/- 3.5 microU/mL). However, the ratio of the T3 increment at 120 min (delta T3) to mean delta TSH (delta T3/mean delta TSH) in patients was 53.9 +/- 29.3 ng/microU, significantly lower than the control value of 239.5 +/- 97.5 ng/microU (P < 0.01), suggesting that the thyroid response to endogenous TSH was blunted. The serum T4 concentration correlated with the mean delta TSH in these patients (r = 0.78; P < 0.05), suggesting that hypothyroidism is dependent on conserved pituitary function. The mean bioactivity to immunoreactivity ratio of basal TSH in patients was 0.97 +/- 0.27 and was not significantly different from the normal value of 1.05 +/- 0.22. One of the two patients with high basal TSH (> 10 microU/mL) had a ratio of 0.59, which is just below the mean +/- SD of normal subjects (0.61), suggesting that most patients had normal TSH bioactivity in vitro. Our findings suggest that in vivo bioactivity of TSH is decreased because of a pituitary disorder, but in vitro bioactivity of TSH is variable in patients with central hypothyroidism.

The effects of dietary fiber from Lagenaria scineraria (yugao-melon) on colonic carcinogenesis in mice

BACKGROUND

The increasing trend of colon cancer in Japan is attributed to changes in dietary habits, that is, increased amounts of fat and decreased amounts of fiber in the diet. The effects of Japanese dietary fiber from Lagenaria scineraria (yugao-melon) on colonic carcinogenesis in mice were examined.

METHODS

Eighteen ICR mice in each group were fed with either a basal diet or a diet containing 5%, 10%, or 20% of yugao powder for 35 weeks. All the mice received a weekly intraperitoneal injection of 1,2-dimethylhydrazine (DMH), 10 mg/kg body weight for 10 weeks. The effects of yugao powder on the mucosal and luminal variables involved in colonic carcinogenesis were then compared with those of wheat bran in the mice without any carcinogen treatment.

RESULTS

The incidence of colon tumors (adenocarcinomas) was lower in the yugao powder diet groups than in the basal diet group at week 35 (24% vs. 50%, P < 0.05). The bile acid concentration in the colon was reduced in all the fiber diet groups except for the 5% yugao powder diet group. The colonic luminal pH acidified as yugao powder contents also increased in the yugao powder diet groups. The findings on the colonic short chain fatty acids, microflora, and mucosal fatty acids and ornithine decarboxylase activity were all inconsistent with a tendency to either develop or to inhibit carcinogenesis in both the fiber diet groups.

CONCLUSIONS

Dietary fiber from yugao-melon suppressed DMH-induced colonic carcinogenesis in mice by lowering the bile acid concentration and pH in the colon. The results of the luminal and mucosal variables examined also suggested that the mechanisms of action of yugao powder against colonic carcinogenesis differed from those of wheat brain.

Decreased expression of protein phosphatase type 2A in HL-60 variant (HL-60RAr) cells resistant to induction of cell differentiation by all-trans retinoic acid

To evaluate the molecular basis for susceptibility of the cell differentiation induced by all-trans retinoic acid (ATRA), we examined biochemical activities and expression of protein phosphatases type 1 (PP1) and type 2A (PP2A) from HL-60 cells that are susceptible to differentiation induced by ATRA and HL-60RAr cells, HL-60 variant cells that are resistant to such induction. One nM of calyculin-A (CAL-A) achieved the enhancement of granulocytic differentiation in ATRA-treated HL-60 (1 microM) cells. ATRA exerted no differential action in HL-60RAr cells, but when used in combination with CAL-A, the differential activity was partly resumed at functional and phenotypic levels without change in morphology. The phosphatase activity in the cytosol from HL-60RAr cells was 50% of that from parental HL-60 cells, but the enzyme activities in either membrane or nuclear fractions showed similar values. The decreased phosphatase activity in the cytosol of HL-60RAr cells was mainly due to the decreased expression of the PP2A catalytic subunit. This low level of PP2A protein was reflected at a relative deficiency in expression of the PP2A beta gene in HL-60RAr cells. The exposure to 1 microM ATRA resulted in downregulation of PP2A catalytic subunit protein in HL-60 cells, but ATRA did not affect PP2A expression in HL60RAr cells. Both cell lines expressed the proteins of each PP1 catalytic subunit isozyme (i.e., PP1 alpha, PP1 gamma, and PP1 delta) at comparable levels. ATRA treatment had no effect on the levels of PP1 isozymes. Our results show a correlation between the extent of PP2A expression and the response of HL-60 and HL-60RAr cells to the differentiative effects of ATRA.