[Assessment of the practicability of coronary risk index as a screening method for ischemic heart disease in preoperative evaluation]

Coronary risk index (CRI) is our newly developed screening method for ischemic heart disease in preoperative evaluation. In this study, we assessed the practicability of CRI examining coronary angiograms (CAG) obtained in 106 patients scheduled for operations. CAG was rated with CAG score, then CRI and CAG score were statistically analyzed. These two parameters showed a significant positive relationship; the higher CRI, the higher CAG score (P < 0.0001). When the patients were divided into five groups by their CRI (0-9, 10-14, 15-19, 20-24, and more than 25), the group with higher CRI contained significantly more patients with severe multivessel coronary lesion (P < 0.0001). Similar results were obtained even in the patient with minimal change in ECG or exercise ECG, or those with minimal chest symptoms (P < 0.001). These results suggests that CRI works effectively as a screening method for ischemic heart disease regardless of abnormalities in ECG or the chest symptoms. More cautious perioperative management should be carried out in patients with higher CRI.

Effect of insulin therapy on body fat distribution in NIDDM patients with secondary sulfonylurea failure: a preliminary report

OBJECTIVE

To clarify the influence of insulin therapy on body weight and fat distribution, we compared these parameters in five non-insulin dependent diabetes mellitus (NIDDM) patients, with secondary sulfonylurea failure, before and after insulin therapy. Body weight increased significantly after instituting insulin treatment. However, the visceral to subcutaneous fat (V/S) ratio decreased significantly due to a marked increase in S-fat without a change in V-fat. Insulin therapy necessitated by sulfonylurea failure does not appear to accelerate the atherogenic process in NIDDM patients as there is no increase in visceral fat.

Micelle Formation of Lithium 1-Perfluoroundecanoate

Solution properties of lithium 1-perfluoroundecanoate have been studied by electroconductivity and membrane potential measurements. The degree of counterion binding to micelles was not precisely determined by the Corrin-Harkins plots. The aggregation numbers and the degrees of counterion binding over the temperature range from 288.2 to 313.2 K have been evaluated by a new method that combined the above two measurements and the mass-action model. The thermodynamic parameters of micellization were determined from the temperature dependence of the parameters obtained. The surfactant with a long perfluoroalkyl chain showed micellization properties much different from the corresponding hydrocarbon surfactant in that the temperature dependence of the aggregation number, the degree of counterion binding, the enthalpy change of micellization, and the entropy change of micellization are much greater. Copyright 1998 Academic Press. Copyright 1998Academic Press

Characterization of soluble artificial proteins with random sequences

The structural and catalytic properties of two soluble random proteins, RP3-42 and RP3-45, of 141 amino acid residues were investigated. Although no marked secondary structure was detected by CD spectrum, sedimentation equilibrium and small-angle X-ray scattering studies showed that they form an oligomeric structure and are as compact as the molten globule. The random proteins have low but distinct esterase activity; the values of the second-order rate constant for the hydrolysis of p-nitrophenol were 0.78 and 1.39 M(-1) s(-1) for RP3-42 and RP3-45, respectively. The differences in the properties of the random and the native proteins are discussed from the evolutionary point of view.

Inhibition of myo-inositol transport causes acute renal failure with selective medullary injury in the rat

Myo-inositol is a major compatible osmolyte in the renal medulla that is accumulated under hypertonic conditions via the Na+/myo-inositol cotransporter (SMIT). We have recently reported that SMIT is predominantly present in the thick ascending limb of Henle (TAL) and is strongly induced by acute NaCl loading, suggesting an important role of myo-inositol in this nephron segment. In the present study, we sought to examine in vivo effects of inhibition of myo-inositol transport using a transport inhibitor, 2-O, C-methylene-myo-inositol (MMI). Intraperitoneal injection of MMI caused acute renal failure in the rats. Serum creatinine and urea nitrogen were significantly increased 12 hours after MMI injection. Morphologic study revealed that the tubular cells were extensively injured in the outer medulla. A considerable number of the tubular cells were injured in the cortex as well. Immunohistochemical study for Tamm-Horsfall protein (THP), which was used for identification of the TAL cells, showed that THP-positive cells were predominantly injured. The tubular injury apparently appeared to worsen when high concentration of NaCl was injected with MMI. Administration of myo-inositol prevented acute renal failure and improved the tubular injury after MMI injection. Furthermore, supplementation of betaine, another osmolyte in the TAL cells, partially prevented the toxic effects of MMI. These results suggest that myo-inositol play a crucial role in the TAL regarding osmoregulation of the cells.

Oxygen dependency of epidermal growth factor receptor binding and DNA synthesis of rat hepatocytes

BACKGROUND/AIMS

Changes in oxygen availability modulate replicative responses in several cell types, but the effects on hepatocyte replication remain unclear. We have studied the effects of transient nonlethal hypoxia on epidermal growth factor receptor binding and epidermal growth factor-induced DNA synthesis of rat hepatocytes.

METHODS

Lactate dehydrogenase activity in culture supernatant, intracellular adenosine triphosphate content, 125I-epidermal growth factor specific binding, epidermal growth factor receptor protein expression, and 3H-thymidine incorporation were compared between hepatocytes cultured in hypoxia and normoxia.

RESULTS

Hypoxia up to 3 h caused no significant increase in lactate dehydrogenase activity in the culture supernatant, while intracellular adenosine triphosphate content decreased time-dependently and was restored to normoxic levels by reoxygenation (nonlethal hypoxia). Concomitantly, 125I-epidermal growth factor specific binding to hepatocytes decreased time-dependently (to 54.1% of normoxia) and was restored to control levels by reoxygenation, although 125I-insulin specific binding was not affected. The decrease in 125I-epidermal growth factor specific binding was explained by the decrease in the number of available epidermal growth factor receptors (21.37+/-3.08 to 12.16+/-1.42 fmol/10(5) cells), while the dissociation constant of the receptor was not affected. The change in the number of available receptors was not considered to be due to receptor degradation-resynthesis, since immunodetection of the epidermal growth factor receptor revealed that the receptor protein expression did not change during hypoxia and reoxygenation, and since neither actinomycin D nor cycloheximide affected the recovery of 125I-epidermal growth factor binding by reoxygenation. Inhibition of epidermal growth factor-induced DNA synthesis after hypoxia (to 75.4% of normoxia by 3 h hypoxia) paralleled the decrease in 125I-epidermal growth factor binding.

CONCLUSIONS

Transient hypoxia, which caused no increase in lactate dehydrogenase leakage but affected intracellular adenosine triphosphate levels, did, however, modulate the number of available epidermal growth factor receptors without affecting the receptor protein expression, and inhibit the epidermal growth factor-induced DNA synthesis of hepatocytes. This suggests that even transient nonlethal hypoxia affects the epidermal growth factor-induced DNA synthesis of rat hepatocytes through reversible changes in the epidermal growth factor receptor molecule, which depends on oxygen availability.

TCV-116 inhibits interstitial fibrosis and HSP47 mRNA in rat obstructive nephropathy

Unilateral ureteral obstruction (UUO) is a well established disease model leading to fibrosis of the obstructed kidney. In this model, involvement of enhanced renin-angiotensin system in the pathogenesis of interstitial fibrosis has been demonstrated. A 47-kDa heat-shock protein (HSP47) was originally identified as a collagen-binding stress protein, and is currently considered to be a collagen-specific molecular chaperone that plays a pivotal role during the biosynthesis and secretion of procollagen from endoplasmic reticulum. To test if HSP47 is involved in interstitial fibrosis in UUO, we examined the expression of HSP47 mRNA in rat UUO kidneys after 12 hours. 1, 4, 7 days of obstruction. HSP47 mRNA expression was significantly increased as early as 12 hours after obstruction and was sustained at the increased level until seven days. Type I collagen mRNA significantly increased after four days of UUO. Fibrotic changes of interstitium appeared in Masson's trichrome stained section after four days. To explore the possible involvement of angiotensin II (Ang II) in HSP47 induction, the effect of Ang II receptor antagonist (TCV-116) and angiotensin converting enzyme inhibitor (lisinopril) was tested. TCV-116 or lisinopril was given to the animals orally once a day at the dose of 10 mg/kg. TCV-116 or lisinopril significantly ameliorated the fibrotic change of interstitium seven days after obstruction. HSP47 and type I collagen mRNA levels in the TCV-116- or lisinopril-treated groups were reduced to about 60% of untreated UUO. A possible involvement of HSP47 in the pathogenesis of interstitial fibrosis in UUO is suggested; however, further investigation is required to identify the signals involved in the induction of HSP47 in UUO.

Presence of anti-FKBP12 autoantibodies in patients with liver allografts: its association with allograft rejection

BACKGROUND

It was reported that autoantibodies against cyclophilin are present in sera from systemic lupus erythematosus. We hypothesized that autoantibodies against FKBP12, another immunophilin, may be present in the plasma of liver allograft recipients, which may affect the clinical outcome of liver allografts.

METHODS

We investigated the relationship between the presence of anti-FKBP12 autoantibodies and rejection episodes in 47 patients treated with FK506 after living-related partial liver transplantation (LRLT). The patients consisted of two groups: 22 with rejection [R(+) group] and 25 without rejection [R(-) group]. The autoantibodies were measured by an indirect ELISA, and the specificity was confirmed by absorption with antigen and immunoblotting.

RESULTS

The autoantibodies were detected in 13 of 22 in the R(+) group (IgG: 5; IgM: 6; both: 2) and in 6 of 25 in the R(-) group (IgG: 2; IgM: 3; both: 1) before LRLT (P=0.0193). After LRLT, they were also detected more frequently in the R(+) group (12 of 22; IgG: 1; IgM: 8; both: 3) than in the R(-) group (2 of 25; IgG: 1; IgM: 1) (P=0.001). In the R(+) group, the mortality of the patients who were positive and negative for the autoantibodies was 6 of 12 and 2 of 10, respectively. The autoantibodies were detected in all four patients with chronic or refractory acute rejection. The autoantibodies were not detected in any of the 34 healthy subjects.

CONCLUSIONS

These results suggest that the presence of the autoantibodies in patients before transplantation is related to rejection, and the presence after transplantation may be associated with patient outcome.

Developmental regulation of Na+ / myo-inositol cotransporter gene expression

myo-Inositol plays a role in many important aspects of cellular regulation including membrane structure, signal transduction and osmoregulation. It is taken up into the cells by the Na+ / myo-inositol cotransporter (SMIT). We investigated developmental changes in the expression of SMIT mRNA and protein in the rat. In the fetal rat brain, SMIT mRNA was abundantly and diffusely expressed throughout the whole brain and the spinal cord. Positive signals were expressed in neuronal and non-neuronal cells in these regions. SMIT is gradually down-regulated nearer birth, but intense signals were still detected in the brain at postnatal day one. In the adult rat brain, very weak hybridization signals were detected throughout whole brain except for the choroid plexus where SMIT mRNA expression remained high. In contrast, the pattern of developmental regulation of SMIT gene expression in the kidney was opposite to that seen in the brain. Signals in the kidney were very weak during embryonic stages, whereas SMIT expression increased significantly after birth. These results suggest that myo-inositol and its transporter play an important role in the CNS developmental stage.

Role of intracellular redox status in apoptosis induction of human T-cell leukemia virus type I-infected lymphocytes by 13-cis-retinoic acid

We have shown that cell cycle progression of human T-cell leukemia virus type I (HTLV-I)-transformed T-cell lines was inhibited by 13-cis-retinoic acid (13cRA). In the present study, we report that 13cRA inhibited proliferation and induced cell death of peripheral blood mononuclear cells obtained from four patients with acute adult T-cell leukemia but not of mitogen- or interleukin 2-activated peripheral blood mononuclear cells from HTLV-I-negative healthy donors. Because HTLV-I-infected lymphocytes are susceptible to oxidative stress, we examined the role of the intracellular redox state in 13cRA-induced cell death using a HTLV-I-positive T-cell line, ATL2, as a model. 13cRA induced apoptosis in ATL2 cells within 48 h in a dose-dependent manner. The ability of 13cRA to induce apoptosis was more potent than that of all-trans-retinoic acid. Apoptosis induction by 13cRA was significantly enhanced by buthionine sulfoximine (BSO), which decreased the levels of intracellular reduced glutathione, although 13cRA by itself did not alter them, suggesting that intracellular reduced glutathione may modulate 13cRA-induced apoptosis. In addition, flow cytometric analysis revealed that 13cRA increased intracellular peroxides in 24 h and that the addition of BSO further enhanced them. Although N-acetylcysteine had only a marginal effect, pretreatment with catalase markedly inhibited 13cRA-induced apoptosis. These results suggest that peroxide generation, ie., oxidative stress, may play a crucial role in the induction of apoptosis by 13cRA and further demonstrate that combined treatment with 13cRA and BSO induces apoptosis of HTLV-I-positive lymphocytes even more potently.

Control of cell cycle progression in human natural killer cells through redox regulation of expression and phosphorylation of retinoblastoma gene product protein

Using thiol deprivation, we have previously shown that the response of natural killer (NK) cells to interleukin-2 (IL-2) is subject to redox regulation downstream of IL-2 binding and internalization. We have now used the IL-2-dependent cell line, NK3.3 to study redox regulation of NK cells further, and found that NK3.3 cells neither incorporated [3H]-thymidine nor completed the G1-S phase transition in medium lacking the thiol-related compounds, L-cystine, and glutathione, despite the presence of sufficient IL-2. Thiol deprivation did not alter the induction of DNA interferon-gamma activated sequence (GAS)-binding activity in response to IL-2. However, the retinoblastoma gene product (RB), a cyclin-dependent kinase (CDK) substrate, was phosphorylated within 24 hours after IL-2 stimulation in standard medium, but its expression and phosphorylation were reduced in thiol-depleted medium in both NK3.3 cells and freshly isolated NK cells. These reductions were not associated with an increased level of p27Kip1, an inhibitor of CDKs CDK6/2 in association with G1 cyclins. Reducing agents, N-acetylcysteine, reduced glutathione or 2-ME restored both RB phosphorylation and DNA synthesis in thiol-deprived NK3.3 cells. The in vitro kinase activities of CDK6 and CDK2 were prematurely increased by thiol deprivation. This enhancement was associated with CDK hyperphosphorylation and prolonged phosphorylation, and could be observed before and beyond IL-2 stimulation. The data suggest the possibility that the premature and prolonged enhancement of CDK activity in thiol-deprived NK cells is associated with, and therefore may contribute to, the reduced expression and phosphorylation of RB, and the associated cell cycle arrest.

Effects of partial nephrectomy on the expression of osmolyte transporters

Na+/myo-inositol cotransporter (SMIT) and Na+/Cl-/betaine-gamma-amino-n-butyric acid transporter (BGT-1) are the major osmolyte transporters that are regulated by extracellular osmolarity. We have recently shown localization and rapid regulation of the mRNAs for these transporters in rat kidney. In the present study, we examined the expression of SMIT and BGT-1 in partial nephrectomized rats in order to assess the change in local osmolarity following reduction of renal mass. Four weeks after 5/6 nephrectomy (NX), the rats were compared to sham-operated control animals (CONT). Northern analysis using RNA of whole kidney indicated that there were little differences in the levels of SMIT and BGT-1 mRNAs between the two groups. In situ hybridization revealed that signals for both transporter mRNAs were markedly reduced in the inner medulla of the remnant kidney. In contrast, these signals in the outer medulla increased following nephrectomy. SMIT signals in the cortex increased as well. Grain density, determined by counting grain number per cell, revealed that the signals in the inner medullary collecting ducts were markedly reduced whereas those in the thick ascending limbs of Henle (TAL) as well as macula densa cells were significantly increased. The signals in the TAL and macula densa were reduced by furosemide administration. The increased expression in NX rats may reflect the increased NaCl transport and high local osmolarity in this segment.

Induction of Na+/myo-inositol co-transporter mRNA after rat cryogenic injury

Myo-inositol is one of the major organic osmolytes in the brain. It is stored in the cells by the Na+/myo-inositol co-transporter (SMIT) which is regulated by extracellular osmolality. First, in order to confirm that local change of the osmolality induces alteration of the SMIT mRNA in brain, we examined change of SMIT mRNA of the animals with hypertonic NaCl application to the cortex. Application of hypertonic NaCl up-regulated the SMIT mRNA expression widely surrounding the application site. We next investigated the role of SMIT in brain during vasogenic edema, we examined expression of SMIT mRNA in the rat brain after cryogenic injury. The expression of SMIT mRNA was markedly increased 12 h after surgery and the induction of the mRNA extended to the entire cortex of the affected side. Up-regulated expression was found predominantly in the neurons in remote areas. The induction of SMIT mRNA was found until the 3rd day after surgery. These findings suggest that osmotic stress may spread over a wide area in the cortex in case of vasogenic edema produced by cryogenic injury and that the cells respond to this stress by increasing SMIT expression.

Osmolarity in renal medulla of transgenic mice regulates transcription via 5'-flanking region of canine BGT1 gene

Betaine is a major compatible osmolyte accumulated in the mammalian kidney medulla and in Madin-Darby canine kidney cells in response to hypertonicity. The accumulation is the result of an increase in maximal velocity of the Na(+)- and Cl-coupled betaine transporter designated BGT1. We have previously cloned the canine BGT1 gene and identified a tonicity-responsive enhancer element (TonE) in its 5'-flanking region. Here we report studies of transgenic mice that have in their genome 2.4 kb of the 5'-flanking region of the canine BGT1 gene in front of a chloramphenicol acetyl-transferase (CAT) reporter. Expression of CAT mRNA was detected only in the renal medulla and was increased by experimental manipulations that increase the tonicity of the renal medulla and decreased by manipulations that decrease medullary tonicity. We conclude that the 2.4-kb 5'-flanking region of the BGT1 gene mediates an increase in transcription in response to hyperosmolarity in the renal medulla.

Synthesis and biological evaluation of 7-hydroxy-3,4-diphenyl-1,2-dihydroisoquinolines as new 4-hydroxytamoxifen analogues

A phenolic 3,4-diphenyl-1,2-dihydroisoquinoline derivative (4a) as a new 4-hydroxytamoxifen analogue and a related compound (4c) were synthesized from 3,4-diphenyl-1,2,3,4-tetrahydroisoquinolin-4-ols (5a, c), which were prepared by intramolecular Barbier reaction of N-(2-iodobenzyl)phenacylamines. Anti-proliferative activities of 4a,c and 5a,c, as well as 4b and 5b prepared previously, against human mammary carcinoma MCF-7 cell line and human nasopharyngeal carcinoma KB cell line were evaluated. The 3,4-diphenyl-1,2-dihydroisoquinoline derivatives (4a,c) and isoquinolin-4-ols (5a,b) were active against MCF-7 cells and were nearly equipotent to the corresponding nonphenolic compound (1a). The mechanism of the anti-proliferative activity of 4a-c against MCF-7 cells is discussed.

Transcriptional activation of a hybrid promoter composed of cytomegalovirus enhancer and beta-actin/beta-globin gene in glomerular epithelial cells in vivo

The aim of this study was to seek a promoter, transactivated selectively in renal cells in vivo by using transgenic (tg) mouse technology. We generated two kinds of tg mouse lines carrying a green fluorescence protein (GFP) cDNA driven either by cytomegalovirus enhancer and beta-actin/beta-globin promoter (CX-GFP) or by elongation factor 1alpha promoter (EF-GFP), and investigated the expression of GFP in the kidney. Microscopic examination of the renal tissues in CX-GFP-tg mice revealed that GFP was expressed only in glomeruli, mainly epithelial cells, but not in tubules, arteries and interstitium. Moreover, in situ hybridization demonstrated that GFP mRNA expression was localized in the glomerular cells. In contrast, GFP was not detectable in the kidney in any of the lines of EF-GFP-tg mouse. To exclude the possible involvement of the GFP cDNA as an enhancer, we constructed tg mice carrying the CX promoter driving a human CD4 cDNA. It was confirmed that the expression patterns of human CD4 in the kidney were quite similar to those of GFP in the kidney of CX-GFP-tg mice. These results strongly suggest that CX promoter could be transactivated in glomerular epithelial cells in vivo.

Osmotic regulation of amino acids and system A transport in Madin-Darby canine kidney cells

The effects of hypertonicity on the intracellular amino acid content and system A transport activity were studied in Madin-Darby canine kidney (MDCK) cells. Total content of 20 amino acids increased from 274 to 689 nmol/mg protein after 8 h of hypertonicity (500 mosmol/ kg), remaining almost constant until after 6 days of hypertonicity. The content of neutral amino acids increased from 77 to 307 and 395 nmol/mg protein after 8 h and 6 days of hypertonicity, respectively, accounting for 73% of the increased amount of total amino acids. In the hypertonic MDCK cells, system A transport activity, measured by Na+-dependent 2-(methylamino)isobutyric acid (MeAIB) uptake, increased approximately 60-fold relative to the uptake in isotonic cells. MeAIB was taken up primarily on the basal side in the isotonic MDCK cells cultured on permeable supports. Extracellular hypertonicity stimulated the MeAIB uptake predominantly on the basal side. These results indicated that amino acids, especially neutral amino acids, can function as volume-regulating osmolytes and that the stimulation of system A activity appears to contribute to the accumulation of neutral amino acids in hypertonic MDCK cells.

The differential osmoregulation and localization of taurine transporter mRNA and Na+/myo-inositol cotransporter mRNA in rat eyes

We studied the cellular localization and osmotic regulation of taurine transporter (TauT) mRNA in the rat eyes using in situ hybridization. TauT mRNA signals were expressed in the ciliary body, and the outer part of the inner nuclear layer (INL), the outer nuclear layer (ONL) and the inner segment (IS) of the adult rat retina. Chronic hypernatrema, induced by gavaging with 1 ml/100 g body weight of 5% NaCl every other day for 7 days, markedly increased in TauT mRNA in the retina compared with control rats. However, there was little change in TauT mRNA in the eyes in acute hypernatremic state that is induced by single injection of high concentration of NaCl. On the contrary, acute hypernatremic rats displayed markedly elevated Na+/myo-inositol cotransporter (SMIT) mRNA in the retina and the iris-ciliary body and the lens epithelium. Under chronic hypernatremic conditions, there was no significant increase in SMIT mRNA in rat eyes. These findings suggest that TauT mRNA is osmotically regulated in vivo to protect retinal neuronal function, especially against chronic hypernatremic conditions, in contrast to rapid up-regulation of SMIT mRNA in acute hypernatremic rats.

Effects of inhibition of myo-inositol transport on MDCK cells under hypertonic environment

To investigate the role of myo-inositol under hypertonic conditions, we examined the effects of inhibition of myo-inositol transport in Madin-Darby canine kidney (MDCK) cells using an analog of myo-inositol, 2-O,C-methylene-myo-inositol (MMI). We first characterized the inhibitory effects of MMI on myo-inositol transport in MDCK cells. The Na+-dependent component of [3H] myo-inositol uptake was inhibited by MMI in a concentration-dependent manner, although MMI did not inhibit the activities of the betaine transporter and system A neutral amino acid transporter. We found decreased affinity for myo-inositol in the presence of MMI, whereas the maximal velocity (Vmax) of the transporter did not change. Thus MMI behaves as a competitive inhibitor of myo-inositol transport with a relatively high inhibition constant (K(i)) value (1.6 mM). Myo-inositol content in hypertonic MDCK cells was markedly reduced in the presence of 5 mM MMI, but MMI itself did not accumulate in these cells. The hypertonic cells began to detach in the presence of MMI 3 days after increasing medium osmolality, whereas MMI did not affect the cells in isotonic medium. We also examined the effects of MMI on colony-forming efficiency of MDCK cells. MMI decreased colony-forming efficiency in a concentration-dependent manner, and addition of myo-inositol returned the efficiency to the value without MMI. Addition of betaine also increased colony-forming efficiency in the presence of MMI. These results indicate that myo-inositol plays an important role in survival and growth under hypertonic environment.

Reducing environment protects sinusoidal lymphocytes isolated from normal human liver from apoptosis

BACKGROUND/AIMS

We previously reported that the populations of lymphocytes and the expression of activated antigens in human sinusoidal mononuclear cells were different from those in peripheral blood mononuclear cells. Attempts to culture these cells for further study failed because they died rapidly under standard culture conditions in vitro after isolation from the liver. In this study, we evaluated the characteristics of cell death and the effects of various culture conditions on the viability of these cells.

METHODS

Sinusoidal mononuclear cells were isolated from University of Wisconsin solution that had been perfused through the portal veins of normal healthy human livers harvested for transplantation into living related recipients.

RESULTS

70% of sinusoidal mononuclear cells cultured in vitro were nonviable within 48 h after isolation, while only 10% of peripheral blood mononuclear cells died under the same conditions. Sinusoidal mononuclear cells showed DNA ladder formation of DNA on electrophoresis and characteristic morphological pattern on electron microscopic examination that suggested they had died in an apoptotic manner. The addition of human liver extracts or 2-mercaptoethanol and reduced glutathione to the cultures rescued the sinusoidal mononuclear cells from apoptosis. Furthermore, diamide, a sulfhydryl group specific oxidant, negated the effect of the liver extract.

CONCLUSION

In comparison with peripheral blood mononuclear cells, human sinusoidal mononuclear cells were more subject to death by apoptosis ex vivo, which was reversed by exogenous agents producing reducing conditions. These results suggested that hepatic sinusoidal mononuclear cells might express a different sensitivity to redox environment than peripheral blood mononuclear cells.

A young man with acute renal failure and severe loin pain

The first case of exercise-induced acute renal failure (EIARF) is reported measuring the blood flow and arterial resistance in the kidney by pulsed Doppler ultrasound. A 20-year-old Japanese male suffered from severe loin pain and non-oliguric acute renal failure after strenuous exercise. Serum myoglobin and creatine phosphokinase were normal and urinary myoglobin was not detectable. The Doppler pattern in several segmental arteries showed a slow end-diastolic velocity (EV) and a high resistance index (RI), indicating increased renal vascular resistance, which suggested severe renal vasoconstriction. Three days later, the EV had apparently increased and the RI normalized in accordance with improvement of renal function. The ultrasound Doppler technique is useful for the detection of a decrease in arterial blood flow on real time and for the diagnosis of EIARF.

Effects of aminoguanidine on serum advanced glycation endproducts, urinary albilmin excretion, mesangial expansion, and glomerular basement membrane thickening in Otsuka Long-Evans Tokushima fatty rats

This study evaluated the effects of treatment with an inhibitor of advanced glycation endproducts, aminoguanidine, on the development of albuminuria, mesangial expansion and glomerular basement membrane (GBM) thickening in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which we found to be an excellent model of non insulin-dependent diabetes mellitus (NIDDM), for its very close similarity to human NIDDM. OLETF rats were randomized into a non-treatment diabetic group (D-group, n = 5) and an aminoguanidine-treated group (AG-group, n = 5). The AG-group was given 100 mg/dl aminoguanidine HCl in free drinking water. Treatment was started at 16 weeks of age. We measured body weight, plasma glucose, total cholesterol, triglycerides and the urinary albumin excretion (UAE) rate before and after treatment at regular intervals. At 56 weeks of age, we measured serum advanced glycation endproducts (AGE), mesangial expansion and glomerular basement membrane. There were no significant differences in pre-treatment body weight, plasma glucose and UAE between the D-group and the AG-group. Likewise, after treatment there were no significant differences in body weight, plasma glucose, total cholesterol, triglycerides and immunoreactive insulin. Significant differences were, however, noted in serum AGE (63.2 +/- 3.5 and 51.8 +/- 3.0 U AGE/ml, P < 0.05), UAE (203.6 +/- 37.7 and 89.8 +/- 18.6 mg/day, P < 0.05), fractional mesangial volume (21.3 +/- 1.7 and 16.7 +/- 0.8%, P < 0.05) and GBM thickness (453 +/- 17 and 366 +/- 50 nm, P < 0.05) between the D-group and the AG-group. Our results suggest that aminoguanidine inhibits the AGE formation and the development of diabetic nephropathy in OLETF rats.

NaCl and/or urea infusion fails to increase renal inner medullary myo-inositol in protein-deprived rats

As we recently demonstrated that in potassium depletion a decrease in inner medullary organic osmolytes might precede and cause a renal concentrating defect, we hypothesized that in the protein deprivation the same mechanism may occur. To clarify the relationship between renal medullary organic osmolytes and urine concentration defects during protein deprivation, we examined the effect of protein malnutrition on organic osmolyte content after water deprivation or sodium and/or urea infusion. Water deprivation did not restore urine urea and osmolality or tissue sodium and urea in protein-deprived rats to control levels. NaCl infusion only increased urinary and medullary Na. Urea infusion increased medullary urea but not urine urea. NaCl plus urea infusion increased only urinary sodium and urea. Regardless of the protocols of hyperosmolality used, protein deprivation significantly decreased the medullary contents of myo-inositol and taurine and the level of sodium-dependent myo-inositol transporter mRNA. We conclude that factors other than NaCl and urea but associated with protein feeding are responsible for the decreased accumulation of organic osmolytes.

Radioimmunoassay and gas chromatography/mass spectrometry for a novel antiglaucoma medication of a prostaglandin derivative, S-1033, in plasma

A radioimmunoassay (RIA) and a gas chromatographic/mass spectrometric (GC/MS) method for a new antiglaucoma medicament, the prostaglandin derivative sodium (5Z, 9 alpha, 11 alpha, 13E)-9,11-dihydroxyprosta-5, 13-dienoate (S-1033), in human and rabbit plasma were investigated. For a competitive RIA, antisera from rabbit and radioiodine-labeled S-1033 were prepared by immunizing a conjugate of S-1033 with bovine serum albumin and by the Bolton and Hunter method, respectively. Pretreatment by C18 solid-phase extraction (SPE) for rabbit plasma sample and further purification by high-performance liquid chromatography (HPLC) for human plasma samples followed by the RIA (SPE/RIA and HPLC/RIA, respectively) were developed. The assay recoveries of SPE/RIA and HPLC/RIA were both excellent and the limits of quantitation were 320 and 10 pg ml-1, respectively. GC/MS for plasma samples after solid-phase extraction and thin-layer chromatographic purification was also developed using deuterium-labeled S-1033 as internal standard. The limit of quantitation was 100 pg ml-1 in human or rabbit plasma. Rabbit plasma samples after administration of this drug were measured by SPE/RIA and GC/MS and the assay results from both methods agreed well. The SPE/RIA, HPLC/RIA and GC/MS assay methods were suitable for measuring samples from preclinical studies, clinical studies and cross-validation, respectively.

Induction of Na+/myo-inositol cotransporter mRNA after focal cerebral ischemia: evidence for extensive osmotic stress in remote areas

Myo-inositol is one of the major organic osmolytes in the brain. It is accumulated into cells through an Na+/ myo-inositol cotransporter (SMIT) that is regulated by extracellular tonicity. To investigate the role of SMIT in the brain after cerebral ischemia, we examined expression of SMIT mRNA in the rat brain after middle cerebral artery occlusion, which would reflect alteration of extracellular tonicity. The expression of SMIT mRNA was markedly increased 12 h after surgery in the cortex of the affected side and lasted until the second day. Increased expression was also found in the contralateral cingulate cortex. Up-regulated expression was found predominantly in the neurons in remote areas, although nonneuronal cells adjacent to the ischemic core also expressed this mRNA. These results suggest that cerebral ischemia causes extensive osmotic stress in brain and that the neuronal cells respond to this stress by increasing SMIT expression.

Involvement of histone hyperacetylation in triggering DNA fragmentation of rat thymocytes undergoing apoptosis

The treatment of rat thymocytes with trichostatin A and sodium butyrate, which are inhibitors of histone deacetylase, resulted in an increase in DNA fragmentation in a concentration-dependent manner. A significant increase in DNA fragmentation induced by these compounds was observed after a lag time of 2 h. Analysis of the fragmented DNA revealed the production of approximately 50 kb DNA fragments and DNA ladders, the biochemical hallmarks of apoptotic cell death. Judging from a laser scanning microscopic analysis, the inhibitors of histone deacetylase induced nuclear condensation, the morphological feature of apoptosis. Biochemical and morphological analyses demonstrated that trichostatin A and sodium butyrate induced thymocyte apoptosis. Furthermore, hyperacetylation of nuclear histones was observed in thymocytes treated with the inhibitors of histone deacetylase. These effects of sodium butyrate and trichostatin A were seen 0.5 and 1 h, respectively, after incubation of the cells. These results thus indicate that hyperacetylation of nucleosomal histones precedes DNA fragmentation in thymocytes undergoing apoptosis induced by trichostatin A and sodium butyrate.

[Regulation of osmolyte transporter gene expression by tonicity]

In response to exposure to hypertonic environment, cells accumulate small organic solutes termed osmolytes that protect them from the adverse effects of hypertonicity. Some osmolytes (myo-inositol, betaine and taurine) are accumulated by specific transporters. Those transporters have been cloned by expression cloning techniques. Transcription of osmolyte transporters is induced by hypertonicity. In situ hybridization reveals the localization of the Na+/myo-inositol cotransporter and the betaine transporter (BGT1) mRNAs in the kidney. The BGT1 gene was cloned and its 5' flanking region has been characterized A 13 bp tonicity responsive enhancer (TONE) has been identified. Analysis of transgenic mice harboring a 5' flanking region of the BGT1 gene, that included TONE, showed that it provides inducible reporter expression in kidney medulla.

Reaction of adenine with 6-hydroxyestrogen 6-sulfates: model compounds to demonstrate carcinogenesis by estrogen

To examine carcinogenesis by estrogens, we investigated the reactivity of 6-hydroxyestrogen 6-sulfates. Two epimeric 6-sulfates, pyridinium 3-methoxyestra-1,3,5(10)-trien-6 alpha-yl sulfate (1) and its 6 beta-isomer (2), were synthesized as model compounds and reacted with adenine under mild conditions to give two common products in the ratios of approximately 3:1 and 5:1, respectively. The major product was identified as N6-[3-methoxyestra-1,3,5(10)-trien-6 beta-yl] adenine (10), accompanied with its 6 alpha-isomer (9), by comparison with synthetic specimens. These results imply that, in the metabolism of naturally occurring estrogens, hydroxylation at the C6-position and subsequent sulfoconjugation of the benzylic hydroxyl group may produce sulfates which react with DNA to initiate carcinogenesis.

Potassium depletion modulates aldose reductase mRNA in rat renal inner medulla

The organic osmolytes present in renal inner medullary cells balance the extracellular hyperosmolality and protect the cell against the effects of high salts and urea. We previously demonstrated that a renal concentrating defect due to potassium depletion was associated with a decrease in organic osmolytes including sorbitol. However, we could not determine whether a reduction in medullary organic osmolyte would be cause or effect of urine concentration defect associated with potassium depletion. We focused on the synthesis of sorbitol catalyzed by the enzyme, aldose reductase. To clarify whether the treatment of potassium depletion would affect aldose reductase when extracellular tonicity, and medullary sodium or potassium was maintained at the level of control rats, we administered a hypertonic solution of NaCl or KCl to potassium-depleted rats and evaluated aldose reductase enzymatic activity and mRNA abundance as well as the medullary contents of organic osmolytes. Either infusion significantly reduced tissue sodium content in potassium-depleted rats. With KCl infusion protocol but not that of NaCl, sorbitol as well as aldose reductase mRNA abundance increased to the control level. Medullary contents of other organic osmolytes exhibited a pattern similar to sorbitol. Data suggested that aldose reductase mRNA abundance was reduced in potassium depletion irrespective of medullary sodium content. A decrease in sorbitol level may precede a urinary concentrating defect. Our finding constitutes the first demonstration of the relationship between a potassium deficiency and the abundance of aldose reductase mRNA, an osmoregulatory protein in the kidney.

Expression of betaine transporter mRNA: its unique localization and rapid regulation in rat kidney

Betaine is a major compatible osmolyte in the renal medulla. It is taken up into cells via the betaine gamma-amino-n-butyric acid transporter (BGT-1). We investigated the localization of BGT-1 mRNA and its acute regulation by NaCl and furosemide administration. In situ hybridization revealed that BGT-1 mRNA is predominantly present in the outer medulla and papilla. Less intense signals were seen in the inner medulla and no signals were found in the cortex. Microscopic examination suggested that intense signals were present in the medullary thick ascending limbs of Henle's loop (MTAL) and the inner medullary collecting ducts (IMCD). A reverse transcription and polymerase chain reaction assay of individual microdissected segments along the nephron confirmed its localization. Intraperitoneal administration of NaCl rapidly increased the signal in the MTAL, and furosemide prevented the increase in BGT-1 mRNA by NaCl loading. In contrast, BGT-1 mRNA in the IMCD is less sensitive to these kinds of acute regulation. These results suggest that BGT-1 expression in the MTAL is rapidly regulated in response to the magnitude of NaCl absorption, as suggested for the expression of Na+/myo-inositol cotransporter.

Preparation of stable aqueous solution of keratins, and physiochemical and biodegradational properties of films

A stable aqueous solution of reduced keratins was prepared by extracting the proteins from wool (Corriedale) with a mixture of urea, mercaptanol, surfactant, and water at 40-60 degrees C. Sodium dodecyl sulfate was especially effective as a surfactant, not only in promoting extraction but also in stabilizing the aqueous protein solution. The proteins had the following constants: MW, 52,000-69,000 daltons; cysteine content, 8-9 mol%; pl about 6.7. A clear film was readily prepared from a keratin solution containing glycerol. The film was insoluble in water and organic solvents including dimethyl sulfoxide. The keratin film was permeable to glucose, urea, and sodium chloride. The keratin film was degraded in vitro (by trypsin) and in vivo (by subcutaneous embedding in mice).

Rapid and transient up-regulation of Na+/myo-inositol cotransporter transcription in the brain of acute hypernatremic rats

The osmoregulatory system is well developed in the brain. Osmolytes contribute to maintenance of cell volume and cellular functions without changing intracellular ionic composition. Myo-inositol is regarded as one of the major osmolytes in the brain. In the present study, we investigated the changes in expressions of sodium myo-inositol cotransporter (SMIT) mRNA in the brain of acute hypernatremic rats by in-situ hybridization and Northern blot methods. Under moderate acute hypernatremic conditions, SMIT mRNA level increased markedly at 1 h and returned to almost control levels at 3 h, in accordance with plasma Na+ concentrations. Especially, distinct increases in SMIT mRNA expression were observed in the granule cells and glial cells in the cerebellum. These findings indicate that SMIT plays an important role in osmoregulation, especially in the early stages of acute hypernatremia in the brain.

Differential utilization of Janus kinase-signal transducer activator of transcription signaling pathways in the stimulation of human natural killer cells by IL-2, IL-12, and IFN-alpha

IL-2-, IL-12-, and IFN-alpha-mediated signaling pathways were analyzed in primary NK cells and in the NK3.3 cell line. Gel mobility shift and immunoprecipitation analyses revealed that in addition to activating STAT3 (signal transducer and activator of transcription-3) and STAT5, IL-2 induced tyrosine and serine phosphorylation of STAT1 alpha, which formed IFN-gamma-activated sequence-binding complexes by itself and with STAT3. Although IL-2 and IFN-alpha activated STAT1 alpha and STAT5, IL-2 predominantly activated STAT5, while IFN-alpha predominantly activated STAT1 alpha. IL-2 induced less STAT1 alpha activation and IFN-alpha induced greater STAT5 activation in NK3.3 cells compared with preactivated primary NK cells. In NK3.3 cells, IL-2 induced comparable formation of c-fos promoter sis-inducible element IFN-gamma-activated sequence-binding complexes containing STAT3 alone with complexes containing STAT3 and STAT1 alpha, while in preactivated primary NK cells, it preferentially induced complexes containing STAT3 and STAT1 alpha. Thus, signaling in NK3.3 cells is not always identical with that in primary NK cells. In contrast to IL-2 and IFN-alpha, IL-12 induced strong tyrosine phosphorylation of STAT4 and variable weak phosphorylation of STAT3. However, supershift analyses using the c-fos promoter sis-inducible element probe showed that IL-12 activated STAT4, STAT1 alpha, and STAT3, and induced complexes containing STAT4 only, STAT4 with STAT1 alpha, STAT3 with STAT1 alpha, or STAT1 alpha only in preactivated primary NK cells. STAT1 alpha activation by IL-12 correlated with increased phosphorylation of serine, but not tyrosine. Finally, IL-2 induced tyrosine phosphorylation of JAK1 and JAK3, while IL-12 induced phosphorylation of JAK2 and TYK2 in both preactivated primary NK and NK3.3 cells. Differential phosphorylation and consequent differential activation of both separate and overlapping STAT proteins by IL-2, IL-12, and IFN-alpha may provide a molecular basis for the similarities and differences in the actions of these cytokines on NK cells.

Depression of dehydroepiandrosterone in Japanese diabetic men--comparison between non-insulin-dependent diabetes mellitus and impaired glucose tolerance

Hyperglycemia is known to reduce dehydroepiandrosterone (DHEA) circulating levels; however, the mechanism by which hyperglycemia decreases DHEA is not elucidated. In this study, serum DHEA and DHEA sulfate (DHEA-S) levels were compared in 50 men with non-insulin-dependent diabetes mellitus (NIDDM) and 50 age-matched men with impaired glucose tolerance (IGT) receiving only diet therapy. Serum concentrations of DHEA and DHEA-S in the NIDDM group were significantly lower than in the IGT group (7.8 and 9.7 nmol/l vs 3.4 and 4.9 mumol/l, respectively; p < 0.01) but there was no significant difference in immunoreactive insulin between the two groups. When the results from both groups were combined, HbA1C was significantly inversely related to DHEA (r = -0.243, p < 0.01) and DHEA-S (r = -0.305, p < 0.01). Immunoreactive insulin showed no correlation with DHEA and DHEA-S. Multiple regression analysis showed that HbA1C was independently negatively related to both DHEA and DHEA-S. We conclude that hyperglycemia may decrease serum DHEA and DHEA-S in Japanese men with NIDDM, but the depression of DHEA(-S) is independent of serum insulin level.

Differential utilization of Janus kinase-signal transducer activator of transcription signaling pathways in the stimulation of human natural killer cells by IL-2, IL-12, and IFN-alpha

IL-2-, IL-12-, and IFN-alpha-mediated signaling pathways were analyzed in primary NK cells and in the NK3.3 cell line. Gel mobility shift and immunoprecipitation analyses revealed that in addition to activating STAT3 (signal transducer and activator of transcription-3) and STAT5, IL-2 induced tyrosine and serine phosphorylation of STAT1 alpha, which formed IFN-gamma-activated sequence-binding complexes by itself and with STAT3. Although IL-2 and IFN-alpha activated STAT1 alpha and STAT5, IL-2 predominantly activated STAT5, while IFN-alpha predominantly activated STAT1 alpha. IL-2 induced less STAT1 alpha activation and IFN-alpha induced greater STAT5 activation in NK3.3 cells compared with preactivated primary NK cells. In NK3.3 cells, IL-2 induced comparable formation of c-fos promoter sis-inducible element IFN-gamma-activated sequence-binding complexes containing STAT3 alone with complexes containing STAT3 and STAT1 alpha, while in preactivated primary NK cells, it preferentially induced complexes containing STAT3 and STAT1 alpha. Thus, signaling in NK3.3 cells is not always identical with that in primary NK cells. In contrast to IL-2 and IFN-alpha, IL-12 induced strong tyrosine phosphorylation of STAT4 and variable weak phosphorylation of STAT3. However, supershift analyses using the c-fos promoter sis-inducible element probe showed that IL-12 activated STAT4, STAT1 alpha, and STAT3, and induced complexes containing STAT4 only, STAT4 with STAT1 alpha, STAT3 with STAT1 alpha, or STAT1 alpha only in preactivated primary NK cells. STAT1 alpha activation by IL-12 correlated with increased phosphorylation of serine, but not tyrosine. Finally, IL-2 induced tyrosine phosphorylation of JAK1 and JAK3, while IL-12 induced phosphorylation of JAK2 and TYK2 in both preactivated primary NK and NK3.3 cells. Differential phosphorylation and consequent differential activation of both separate and overlapping STAT proteins by IL-2, IL-12, and IFN-alpha may provide a molecular basis for the similarities and differences in the actions of these cytokines on NK cells.

Target cell-induced apoptosis of interleukin-2-activated human natural killer cells: roles of cell surface molecules and intracellular events

We previously reported that natural killer (NK)-sensitive target cells, K562, kill interleukin-2-stimulated (lymphokine-activated killer [LAK]) but not unstimulated NK cells. We have now investigated the molecular basis of this phenomenon. Soluble monoclonal antibody (MoAb) to CD18 inhibited 75% of K562-induced DNA fragmentation and membrane disruption, whereas blocking MoAb to Fas partially inhibited only the DNA fragmentation. MoAbs to CD2, CD11a, CD11b, B7, or CD16 had limited or no effect on K562-induced death of LAK cells. Receptor ligation with either immobilized MoAb to CD18 or Fas induced membrane disruption and DNA degradation in LAK cells independently of K562, and MoAb to CD18, CD11a, or CD11b enhanced DNA fragmentation induced by anti-Fas. Fas-L-transfected Raji cells also killed LAK cells, but only if Fas-L expression was amplified. K562 cells rapidly triggered protein phosphorylation in LAK cells, and the tyrosine kinase inhibitor, Herbimycin A, inhibited DNA fragmentation and membrane disruption. Protease inhibitors strongly suppressed K562-mediated DNA fragmentation of LAK cells, but not membrane disruption. In conclusion, (1) K562-induced death of LAK cells involves primarily CD18, although other molecules, such as Fas, may also be involved; (2) K562-mediated apoptosis of LAK cells requires tyrosine phosphorylation and protease activity; (3) engagement of Fas by immobilized MoAb or Fas-L on target cells can also kill LAK cells; and (4) Fas-immobilized MoAb synergizes with coimmobilized MoAb to CD11a, CD11b, or CD18 for LAK cell killing. Activation-induced death of NK cells may represent a mechanism for NK cell regulation.

Hyperglycemia decreases dehydroepiandrosterone in Japanese male with impaired glucose tolerance and low insulin response

Recent studies indicate that experimentally induced hyperinsulinemia may reduce serum dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulfate (DHEA-S). Serum DHEA and DHEA-S decrease in diabetic patients, but the mechanism by which hyperglycemia decreases DHEA and DHEA-S is unknown. In this study, we investigated the effect of hyperglycemia on DHEA and DHEA-S in impaired glucose tolerance (IGT) by means of the 75g-oral glucose tolerance test (OGTT). We selected 30 male IGT patients receiving diet therapy only, whose insulinogenic Index was under 0.3. Oral glucose challenge significantly reduced DHEA (P = 0.0001) and DHEA-S (P < 0.05) at 60 and 120 min after OGTT. Setting the value of DHEA and DHEA-S at time zero as 100%, we calculated the DHEA and DHEA-S values at 60 and 120 min after OGTT as %DHEA(-S) 60 min and %DHEA(-S) 120 min, respectively. DHEA and DHEA-S at time zero showed no correlation with BMI, HbA1c, the sum of insulin values (sigma IRI) or the area under the curve of plasma glucose (AUC). We found decreases in %DHEA 60 min (r = -0.411, P < 0.05), %DHEA-S 60 min (r = -0.508, P < 0.01) and %DHEA-S 120 min (r = -0.393, P < 0.05) as AUC increased, but sigma IRI showed no correlation with %DHEA(-S) 60 min or %DHEA(-S)120 min. We conclude that the depression of DHEA and DHEA-S after OGTT is attributable to hyperglycemia in male Japanese IGT with low insulin response.

Angiotensin I-converting enzyme insertion/deletion polymorphism: potential significance in nephrology

Angiotensin I-converting enzyme (ACE) plays a pivotal role in cardiovascular homeostasis and by activating angiotensin I into angiotensin II and inactivating bradykinin. These two peptides play antagonistic roles on the cardiovascular system by regulating vascular tone and vascular smooth muscle cell proliferation. Identification of the ACE gene as a genetic marker for various forms of cardiovascular disease is a recent result of the progress made in molecular biology and genetics. The insertion/deletion (ID) polymorphism of the ACE gene defined by the presence or absence of the 287 base pair Alu sequence situated in intron 16 has been investigated as a possible genetic marker for a variety of cardiovascular disease including myocardial infarction, essential hypertension, cardiomyopathy, and diabetic vascular complications. This paper reviews prior reports and briefly describes our recent study on the association of the ACE I/D polymorphism and antiproteinuric effect of ACE inhibitors in patients with proteinuria.

McArdle's disease with non-insulin-dependent diabetes mellitus: the beneficial effects of hyperglycemia and hyperinsulinemia for exercise intolerance

A 64-year-old female with McArdle's disease and non-insulin-dependent diabetes mellitus (NIDDM) is reported. She had none of the characteristic symptoms of McArdle's disease such as muscle cramps but her serum creatine kinase level was elevated. Muscle biopsy with negative muscle phosphorylase staining showed McArdle's disease. Modified forearm ischemic exercise test was done at two conditions; fasting and two hours after a meal. When fasting, the level of lactic acid did not elevate after exercise. After a meal, however, the serum lactic acid level rose with the elevation of plasma glucose and IRI. Thus, we suggested that high plasma glucose and insulin due to NIDDM may induce blood-borne glucose uptake with exercise.

Cellular localization of Na+/MYO-inositol co-transporter mRNA in the rat brain

The distribution of Na+/MYO-inositol co-transporter (SMIT) mRNA in the rat brain was studied by in situ hybridization histochemistry. The highest levels of SMIT mRNA were observed in the choroid plexus. Intense hybridization signals were found in the pineal gland, the area postrema, the hippocampus, the locus coeruleus, the suprachiasmatic nucleus, the olfactory bulb and the Purkinje cell and granule cell layers of the cerebellum. Low to moderate levels of labelling were detected in almost all neurones and small glia-like cells throughout the brain. These results suggest that almost all cells in the brain possess an SMIT-mediated osmotic and ionic regulatory system, and uneven densities of positive SMIT mRNA signals may reflect the differences in sensitivity of the cells to osmotic and ionic changes and also reflect differences in permeability of capillaries.

Target-induced death by apoptosis in human lymphokine-activated natural killer cells

Activated human natural killer (NK) cells undergo rapid apoptotic cell death after ligand binding to the Fc receptor (CD16). We examined whether human NK cells die after engagement in cytolytic functions. Peripheral blood NK cells, with and without prior activation in vitro with interleukin-2 (IL-2), were tested for the occurrence of cell death after incubation with K562, the prototype NK-sensitive target cell. A proportion (15.2%) of NK cells that were stimulated for 3 days with IL-2 and then incubated for 4 hours with K562 cells showed rapid cell death, but NK cells not stimulated with IL-2 did not. This cell death was found to involve nuclear condensation and fragmentation and DNA cleavage, all of which are characteristic of apoptosis. These data indicate that a proportion of activated human NK cells undergo apoptosis as they engage in target cell lysis. Target-induced NK cell death may represent an important mechanism for regulation of inflammatory processes involving NK cells.

A low-affinity vasopressin V2-receptor gene in a kindred with X-linked nephrogenic diabetes insipidus

In this study, a mutation in vasopressin Type 2 receptor (V2R) in a patient with hereditary nephrogenic diabetes insipidus (NDI) has been identified and characterized. The sequencing of the V2R gene from the patient revealed that there was a missense mutation (TAT to TGT) resulting in the substitution of 205Tyr for Cys in the putative third extracellular domain. The expression analysis in COS cells showed that the binding affinity of the mutant receptor (KD = 19.8 nM) for arginine vasopressin was much lower than that of the wild-type receptor (KD = 1.8 nM) so that intracellular cAMP production stimulated by arginine vasopressin was impaired in cells with the mutant V2R. From these results, it was concluded that the single amino-acid substitution of V2R is responsible for this familial disease.

Different expression patterns of cyclins A, D1 and E in human colorectal cancer

The expressions of cyclins A, D1 and E at the protein level were investigated by Western blotting in human colorectal carcinomas and in adjacent non-neoplastic colorectal mucosas. Cyclin E was higher in the cancer tissue than in the non-neoplastic mucosa in 92% patients (35 out of 38 cases). However, the cyclin A expression of the mucosa was higher than that of the cancer tissue in 63% (25 out of 40 cases) cases, and only 4 (10%) cancers had higher cyclin A expression. Eleven cancers (27%) demonstrated expression equivalent to that in the mucosa. Equal expression of cyclin D1 in cancer and mucosal tissues was found in 51% cases (20/39), lower expression of cyclin D1 by cancer tissues was demonstrated in 41% cases (16/39) and only three cancers showed higher expression than the mucosa. Proliferating-cell nuclear antigen immunohistochemistry revealed that the labeling index of the cancer tissue was 43.5 +/- 8.3% while that of the mucosa was only 14.8 +/- 5.1%. These results proved that colorectal cancers express high levels of cyclin E, consistent with a high rate of cell proliferation, whereas most of such cancer lose control of cyclin A and cyclin D1 expression.

Aldose reductase and myo-inositol transporter mRNA are independently regulated in rat renal medulla

During antidiuresis, renal papillary cells accumulate organic osmolytes preferentially over inorganic ions. It has been previously demonstrated that sodium infusion increased all of these organic osmolytes except myo-inositol (1). Conversely, urea infusion increased only glycerophosphorylcholine significantly. In addition to sodium and urea, potassium localized in tissue and urine influenced the composition of organic osmolytes. The goal of this study was to clarify how the level of mRNA of osmoregulatory protein is regulated by the extracellular solutes and how it affects the accumulation of organic osmolytes. To clarify the relationship between intra- or extracellular solutes and the regulation of Na/myo-inositol cotransporter and aldose reductase, mRNA of these osmo-regulatory proteins were determined in water-deprived sodium chloride-, potassium chloride-, and urea-loaded rats. Medullary content of sorbitol and myo-inositol, and aldose-reductase enzymatic activity were measured simultaneously in these animals. In water-deprived, sodium-loaded, and potassium-loaded rats, the inner medullary sorbitol content increased significantly in accordance with the rise in the enzymatic activity and the level of aldose reductase mRNA. In urea-loaded rats, both the sorbitol content and the level of aldose reductase mRNA were equal to that in hydrated rats. In the outer and inner medullary tissues, the level of myo-inositol transporter mRNA was increased in all hyperosmolality protocols, including urea infusion, which corresponded with the rise in myo-inositol content. In conclusion, potassium chloride infusion is as effective as water deprivation and sodium chloride infusion in raising the level of aldose reductase and myo-inositol transporter mRNA, whereas urea influenced only myo-inositol transporter. Although aldose reductase and myo-inositol transporter are osmoregulatory proteins in the renal medulla, the levels of aldose reductase and sodium-dependent myo-inositol transporter mRNA are regulated independently.

Expression of Na+/myo-inositol cotransporter mRNA in normal and hypertonic stress rat eyes

We studied the localization of Na+/myo-inositol cotransporter (SMIT) mRNA in normal and hypertonic stress rat eyes by in situ hybridization histochemistry using cRNA probes. SMIT mRNA signals were observed in the iris-ciliary body, the lens epithelial cells, and the ganglion cell layer and the inner nuclear layer of the retina. There was a rapid increase on SMIT mRNA in the retina of hypertonic stress rats compared with control rats. These findings suggest that Na+/myo-inositol cotransporter gene expression is osmotically regulated in vivo to protect retinal neuronal function against hypertonic stress.

Expression of Na+/myo-inositol cotransporter mRNA in the inner ear of the rat

We have demonstrated the cellular localization of Na+/myo-inositol cotransporter (SMIT) mRNA in the rat inner ear by in situ hybridization. In the cochlea, the most intense SMIT mRNA signals were observed in fibrocytes of the spiral ligament, moderate signals were found in the spiral limbus, inner hair cells and spiral ganglion cells, while the hybridization signals were almost undetectable in the marginal cells of the stria vascularis and outer hair cells. In the vestibular system, moderate hybridization signals were found in the sensory epithelium, fibrocytes and vestibular ganglion cells. These findings suggest that SMIT plays an important role in maintenance of intracellular ionic balance and cell volume in the inner ear, especially in the fibrocytes associated with generation of the ion gradients between the endolymph and perilymph.