Somatic embryogenesis and plant regeneration in chrysanthemum (Dendranthema grandiflorum (Ramat.) Kitamura)

 Somatic embryogenesis was observed in ray-floret explants of Dendranthema grandiflorum (Ramat.) Kitamura cv. Aboukyu on Murashige and Skoog medium containing high concentrations of 3-indoleacetic acid (IAA) and kinetin. 1-Naphthaleneacetic acid also induced somatic embryogenesis but indole-3-butyric acid or 2,4-dichlorophenoxy acetic acid did not. Other cytokinins, such as 6-benzylaminopurine (BAP) and thidiazuron, were also not effective. No embryos were seen at lower IAA concentrations with kinetin and various concentrations of BAP, although higher BAP concentrations yielded many adventitious shoots. In contrast, no somatic embryogenesis was observed from leaves using any combination of plant growth regulators. Histologically, primordia showed a typical embryo shape with a well-developed vascular bundle between the shoot and the root primordia. Embryos had both stomata cells and a root system with polarity. Plants were efficiently regenerated from ray floret-derived embryos subcultured in the appropriate medium.

Vitamin B6 supplementation can improve peripheral polyneuropathy in patients with chronic renal failure on high-flux haemodialysis and human recombinant erythropoietin

BACKGROUND

High-flux haemodialysis (HD) has recently been vigorously promoted as a novel standard, and it can indeed efficiently reduce the occurrence of most uraemic symptoms due to middle molecular toxins and/or underdialysis. However, some symptoms remain problematical, particularly peripheral polyneuropathy (PPN). One of the possible reasons for this is that the patients may have low concentrations of some nutrients, e.g. vitamin B(6), necessary for normal peripheral neuron function.

METHODS

Predialysis serum pyridoxal-5'-phosphate (P5P) level was determined in 36 chronic HD patients who were undergoing high-flux HD and receiving human recombinant erythropoietin. Among them, 26 patients suffered from PPN. Prior to supplementation, these 26 patients were examined and their neurological symptoms were ranked according to our PPN symptom score. Vitamin B(6) (60 mg/day) was randomly prescribed to 14 of them, and vitamin B(12) (500 microg/day) was prescribed to the others. After 4 weeks, all the patients were re-examined.

RESULTS

We found that predialysis serum P5P levels of HD patients with PPN were not significantly lower than those of matched HD patients without PPN. Nonetheless, it was demonstrated that supplementation with vitamin B(6) for 4 weeks significantly increased the predialysis level of P5P and dramatically attenuated PPN symptoms compared with initial symptoms. No improvement was observed in response to vitamin B(12) supplementation.

CONCLUSION

This result suggests that although vitamin B(6) deficiency could not be demonstrated in patients with chronic renal failure on high-flux HD, vitamin B(6) supplementation was effective in improving PPN symptoms of various aetiologies, possibly because of vitamin B(6) resistance to PPN in these patients.

Identification of hepatic tamoxifen-DNA adducts in mice: alpha-(N(2)-deoxyguanosinyl)tamoxifen and alpha-(N(2)-deoxyguanosinyl)tamoxifen N-oxide

Tamoxifen-DNA adducts detected in the liver of mice treated with tamoxifen have not yet been identified. In the present study a new type of tamoxifen-DNA adduct, four stereoisomers of alpha-(N:(2)-deoxyguanosinyl)tamoxifen N:-oxide 3'-monophosphate (dG(3'P)-N:(2)-TAM N:-oxide) were prepared as standard DNA adducts by reacting 2'-deoxyguanosine 3'-monophosphate with trans-alpha-acetoxytamoxifen N:-oxide in addition to four stereoisomers of alpha-(N:(2)-deoxyguano- sinyl)tamoxifen 3'-monophosphate (dG(3'P)-N:(2)-TAM) that was reported previously. Liquid chromatography-electrospray ionization-mass spectrometry of the reaction products gave the most abundant ion at m/z 731 ([M - H](-)), which corresponded to dG(3'P)-N:(2)-TAM N:-oxide. The modified products digested by alkaline phosphatase corresponded to the isomers of dG-N:(2)-TAM N:-oxide whose structures were identified previously by mass spectrometry and nuclear magnetic resonance. Using these standard markers, we analyzed the hepatic DNA adducts of female DBA/2 mice treated with tamoxifen at a dosage of 120 mg/kg/day for 7 days by (32)P-post-labeling coupled with an HPLC/radioactive detector. Mixtures of eight isomers of dG(3'P)-N:(2)-TAM and dG(3'P)-N:(2)-TAM N-oxide were separated into six peaks, since each of the cis epimers were not separated under the present HPLC conditions. Nine adducts were detected in all liver samples of mice. An epimer of trans-dG(3'P)-N:(2)-TAM was detected as the principal DNA adduct at a level of 29.0 adducts/10(8) nucleotides, which accounted for 53.3% of the total tamoxifen-DNA adducts. Lesser amounts of cis-dG(3'P)-N:(2)-TAM (2.8%) were also observed. An epimer of the trans-dG(3'P)-N:(2)-TAM N:-oxide (3.9 adducts/10(8) nucleotides) was detected as the third biggest adduct (7.2% of the total). The cis-dG(3'P)-N:(2)-TAM N:-oxide (0.4 adducts/10(8) nucleotides) accounted for 0.7% of the total. Thus, dG(3'P)-N:(2)-TAM and dG(3'P)-N:(2)-TAM N:-oxide were identified in tamoxifen-treated mouse liver.

Influence of the timing of initiating antihypertensive therapy in hypertensive rats with renal failure

The important contribution of hypertension to the progression of renal failure is well realized. However, it have been less discussed which drugs are suitable for the different stages of progressive renal failure. The present study examined the effects of timing of antihypertensive therapy using calcium channel blocker and angiotensin converting enzyme inhibitor in 5/6 nephrectomized spontaneously hypertensive rats (SHRs). Forty male 6 week old SHRs were divided into 5 groups (n=8 in each group), and they were placed on a high salt diet after 5/6 nephrectomy. Group 1, high salt diet without any drug. Group 2 received 0.2 mg/kg/day of amlodipine and group 3 received 0.2 mg/kg/day of enalapril mixed in the high salt diet from week 6 respectively. Similarly group 4 received the same doses of amlodipine, and group 5 received the same doses of enalapril from week 10. Each drug protected from increasing blood pressure in 4 groups, and no significant difference was observed between the effects of amlodipine and enalapril. Proteinuria was reduced with both drugs. In histopathological evaluation, glomerulosclerosis was controlled only in group 2, and arterio/olosclerosis was significantly suppressed in all treated groups except group 5. From these results, both amlodipine and enalapril are renal protective in early stage of renal failure with hypertension. However, in advanced stage of renal failure, amlodipine is superior in its renal protective effect.

CD134L engagement enhances human B cell Ig production: CD154/CD40, CD70/CD27, and CD134/CD134L interactions coordinately regulate T cell-dependent B cell responses

CD134 is a member of the TNFR family expressed on activated T cells, whose ligand, CD134L, is found preferentially on activated B cells. We have previously reported that the CD70/CD27 interaction may be more important in the induction of plasma cell differentiation after the expansion phase induced by the CD154/CD40 interaction has occurred. When CD134-transfected cells were added to PBMCs stimulated with pokeweed mitogen, IgG production was enhanced in a dose-dependent fashion. Addition of CD134-transfected cells to B cells stimulated with Staphylococcus aureus Cowan I strain/IL-2 resulted in little if any enhancement of B cell IgG production and proliferation. We found that while CD134-transfected cells induced no IgG production by themselves, it greatly enhanced IgG production in the presence of CD40 stimulation or T cell cytokines such as IL-4 and IL-10. The addition of CD134-transfected cells showed only a slight increase in the number of plasma cells compared with that in the culture without them, indicating that an increased Ig production rate per cell is responsible for the observed enhancing effect of CD134L engagement rather than increase in plasma cell generation. These results strongly suggest different and sequential roles of the TNF/TNFR family molecules in human T cell-dependent B cell responses through cell-cell contacts and the cytokine network.

Role of T lymphocytes in renal disease in HIV-transgenic mice

The pathogenesis of human immunodeficiency virus (HIV)-associated focal segmental glomerulosclerosis (FSGS) has remained obscure. It has been proposed that renal parenchymal cells may be infected with HIV-1. If such infection occurs, the target cells would be expected to express viral proteins and thus could be targets for cytotoxic T lymphocytes. We previously described mice transgenic for a gag-pol-deleted HIV-1 genome that developed FSGS. In the present study, we tested the requirement for functional T cells in the evolution of renal disease in this model. We bred the HIV-transgenic mice (T26) with athymic nude mice to produce athymic T26 mice. We confirmed by flow cytometry of peripheral blood, thymus, lymph node, and spleen that the athymic T26 mice lacked mature T cells. The athymic T26 mice developed renal disease characterized by FSGS, tubular atrophy and dilatation, and interstitial infiltrate that was qualitatively identical to that seen in the parental T26 mice. Quantitative assessment of the athymic T26 mouse kidneys showed that glomerulosclerosis, tubular injury, and interstitial infiltrate were less severe compared with the parental T26 mouse kidneys. Although T26 mouse kidneys had a mixed cellular infiltrate composed of CD4 cells, CD8 cells, and macrophages, interstitial infiltrates within the athymic T26 mouse kidneys included macrophages but lacked both CD4 and CD8 cells. The renal expression of the HIV transgene was 1. 7-fold greater in T26 mice compared with athymic T26 mice. We conclude that mature T cells are not absolutely required for the development of HIV-associated nephropathy in transgenic mice but that, in their absence, renal disease is significantly milder. These data suggest that T-cell-mediated cytotoxicity directed against renal cells expressing virally encoded proteins is not an essential feature of renal pathogenesis in this model.

Visualization of the secretory process involved in Ca2+-activated fluid secretion from rat submandibular glands using the fluorescent dye, calcein

The central feature of fluid and electrolyte secretion by salivary acinar cells is transepithelial Cl- movement as a driving force for the secretion. However, little is known about the membrane localization and regulation by agonists of various anion channels. To characterize the anion transport and fluid secretion, we visualized the secretory process induced by the cholinergic agonist, carbachol (CCh), using the anionic fluorescent dye, calcein, under a confocal laser scanning microscope. The fluorescence of calcein loaded into the isolated acini was spread diffusely throughout the cytoplasm and was less intense in the secretory vesicles which occupied the apical pole. Cytoplasmic calcein was released into intercellular canaliculi just after the addition of CCh, depending upon a rise in [Ca2+]i by Ca2+ release from intracellular stores. Thereafter, the formation of watery vacuoles connected with intercellular canaliculi was visualized in the calcein-loaded acini, depending upon external Ca2+. Both the calcein release and vacuole formation were inhibited by suppressing the Ca(2+)-activated K+ efflux. The calcein release was also affected by the external anion substitution, suggesting that calcein is released through an anion channel. In the isolated, perfused glands, CCh-induced fluid secretion was sustained in two phases, whereas the loaded calcein was initially and transiently released into the saliva. By revealing the [Ca2+]i dependence and sensitivities to channel blockers, our results suggest that the initial phase of CCh-induced fluid secretion was evoked in association with the release of the organic anion, calcein, and the late phase of fluid secretion, during which calcein is less permeable, was associated with the formation of watery vacuoles. Thus, the anion channels possessing the distinct property of anion permeation may be activated in the initial phase and late phase. These results indicate that the anionic fluorescent dye, calcein, is useful for visualizing the process of Ca(2+)-dependent fluid secretion, and for clarifying the relation between fluid secretion and anion transport.

Zinc-finger genes that specifically express in pistil secretory tissues of petunia

Tissue-specific expression patterns of petunia zinc-finger genes, ZPT2-10 and ZPT3-3, were analyzed by using GUS reporter system. The GUS expression directed by ZPT2-10 promoter was specifically found in the stylar transmitting tissue of pistil, and that by ZPT3-3 promoter in stigmatic and stylar transmitting tissues. These tissues play important roles in reproductive process. We discuss possible roles of the zinc-finger proteins in these specialized tissues.

cAMP-Dependent potentiation of the Ca(2+)-activated release of the anionic fluorescent dye, calcein, from rat parotid acinar cells

A recent study indicates that elevation of [Ca(2+)](i) enhances the release of calcein, an anionic fluorescent dye, from isolated exocrine acinar cells, so cytoplasmic calcein is useful for monitoring the secretion of organic anions. In this study, we investigated the effect of cAMP on the calcein release evoked by elevation of [Ca(2+)](i). Isoproterenol, forskolin and dibutyryl cyclic AMP (dbcAMP) did not induce the release of calcein from isolated parotid acinar cells, but they potentiated the carbachol-induced release of calcein. Although cytoplasmic calcein is released through an increase in [Ca(2+)](i), isoproterenol potentiated the carbachol-induced release of calcein without affecting the increase in [Ca(2+)](i) evoked by a high concentration of carbachol (10(-6) M). Charybdotoxin, a K(+) channel blocker, inhibited both the carbachol-induced release and the potentiation by isoproterenol. However, the calcein permeation pathways mediating the carbachol-induced release and the isoproterenol-potentiated release exhibited distinct sensitivities to anion channel blockers. Our results indicate that the calcein release induced by carbachol is potentiated through an increase in intracellular levels of cAMP. Although both the Ca(2+)-activated release and the cAMP-potentiated release may be coupled to Ca(2+)-activated K(+) efflux, increases in both [Ca(2+)](i) and [cAMP](i) may activate the calcein conduction pathway which is not activated by an increase in [Ca(2+)](i) alone.

Etretinate therapy for papuloerythroderma

Papuloerythroderma, first reported by Ofuji et al. (1984), is a rare cutaneous disorder whose pathogenesis remains unknown. Owing to the small number of cases, there is no recommended choice of treatment. This is the first report on the efficacy of etretinate for papuloerythroderma. Seven male cases ranging in age from 65 to 84 years were treated with moderate doses (0.2-0.6 mg/kg/day) of etretinate. All but one case showed quick and excellent responses and the chronic recalcitrant erythrodermatous lesions disappeared within 2-5 weeks. Eventually all the seven cases could be brought into remission. Once remission was achieved, etretinate was tapered by 0.1-0.2 mg/kg/day over a period of 2-4 weeks. One case remained in complete remission after cessation of etretinate without any treatment for 16 months. Another case could stop etretinate treatment and the subsequent recurrence of papular eruption could be managed by topical steroids. In the other five cases remission could be maintained by daily doses of 0.16-0.36 mg/kg etretinate. None of the patients developed severe side effects. Our observation suggests that etretinate is a safe and effective agent for papuloerythroderma.

A cystatin-related gene, testatin/cresp, shows male-specific expression in germ and somatic cells from the initial stage of murine gonadal sex-differentiation

Sex-differentiation in mammals initiates at mid-gestation when the differentiation of Sertoli cells is triggered by the expression of the testis-determining gene, Sry. However, little is known about the succeeding germ-soma interaction that directs the sex-differentiation of germ cells. We carried out subtraction and differential screening between male and female gonads at 13.5 dpc (days post coitum). A novel cystatin-related gene was identified and named cresp (cystatin-related expressed in Sertoli and spermatogonia), and has recently been reported independently under the name testatin (Töhönen et al., 1998). The presumed amino acid sequence of testatin/cresp showed considerable homology to the cystatin family, but it lacked a few critical amino acid residues for the cysteine-protease inhibitory activity. A 0.7 kb RNA was detected by northern blotting specifically in the fetal and adult testes from 11.5 dpc and expression increased between 11.5 dpc and 12.5 dpc. Using RT-PCR analysis, the testatin/cresp mRNA was first detectable at 9.5 dpc in both male and female embryos but it was maintained only in the male. In females, the expression became weaker at 11.5 dpc and was undetectable after 12.0 dpc. In situ hybridization and immunohistochemical analyses, as well as single cell RT-PCR analysis, showed that the testatin/cresp mRNA was localized specifically in both the (pro)spermatogonia and Sertoli cells in the testis from 12.5 dpc to adult. Thus, expression of the testatin/cresp gene is upregulated in male gonads but downregulated in females immediately after the initiation of sex-differentiation, suggesting roles in the early developmental cascade of testis such as the germ-soma interaction.

Tamoxifen-DNA adducts formed by alpha-acetoxytamoxifen N-oxide

DNA adduct formation is assumed to be a major carcinogenic event, leading to the development of endometrial cancer in breast cancer patients taking tamoxifen and healthy women enrolled in a tamoxifen chemopreventive trial. To determine whether DNA adducts were formed by tamoxifen, trans- and cis-alpha-acetoxytamoxifen N-oxides were synthesized as model-activated forms via major tamoxifen metabolites, tamoxifen N-oxide and alpha-hydroxytamoxifen N-oxide. When alpha-acetoxytamoxifen N-oxide was reacted with human DNA, at least three DNA adducts were detected by (32)P-postlabeling coupled with HPLC. The total amount of DNA adducts formed by trans-alpha-hydroxytamoxifen N-oxide was 1.5-fold higher than that formed by the cis form. Both trans- and cis-alpha-acetoxytamoxifen N-oxide reacted with 2'-deoxyguanosine, resulting in the formation of three adducts (fr-1, fr-2-1, and fr-2-2). These products were studied using mass spectroscopy and proton magnetic resonance spectroscopy. fr-1 was identified as a mixture of the epimers of trans-alpha-(N(2)-deoxyguanosinyl)tamoxifen N-oxide. fr-2-1 and fr-2-2 were determined to be epimers of cis-alpha-(N(2)-deoxyguanosinyl)tamoxifen N-oxide.

Two novel cysteine substitutions (C1263R and C1995S) of thyroglobulin cause a defect in intracellular transport of thyroglobulin in patients with congenital goiter and the variant type of adenomatous goiter

We analyzed the thyroglobulin (Tg) gene of 2 unrelated patients with congenital goiter and the Tg gene of 2 siblings with the variant type of adenomatous goiter. The clinical characteristics of the patients with congenital goiter and the variant type of adenomatous goiter were very similar, except for serum Tg levels, which were less than 15 pmol/L in the patients with congenital goiter, but 117-181 pmol/L in the patients with the variant type of adenomatous goiter (normal, 15-50 pmol/L). The tissue content of Tg in the thyroid glands of all 4 patients was reduced at 0.9-3.8% of total protein (normal, 19-40%). The missense mutation C1263R was detected in the 2 unrelated patients with congenital goiter; the pedigree study showed an autosomal recessive pattern of inheritance. In the 2 siblings with the variant type of adenomatous goiter, the missense mutation C1995S was homozygously detected. In the Tg complementary DNA of 110 normal subjects, the allelic frequencies of the C1263R and C1995S mutations were each less than 0.5%. Also in the normal subjects were detected 35 nucleotide polymorphisms, the insertion of 3 nucleotides, and 1 alternative splicing, each of which was not associated with any specific thyroid disease. From these data, the molecular mechanism of the C1263R and C1995S mutations was elucidated. We first analyzed the carbohydrate residues of C1263R Tg and C1995S Tg. Sensitivity to treatment by endoglycosidase H suggests that C1263R Tg and C1995S Tg were retained in the endoplasmic reticulum (ER). Also, the presence of endoglycosidase H-resistant Tg as well as endoglycosidase H-sensitive Tg in the patients with the variant type of adenomatous goiter suggests that a fraction of C1995S Tg was transported to the Golgi and associated with the mildly increased serum Tg levels. Native PAGE and Western blot analysis with anti-Tg antibody showed that C1263R Tg and C1995S Tg form high mol wt aggregates in the ER. Our results suggest that missense mutations that replace cysteine with either arginine or serine cause an abnormal three-dimensional structure of Tg. Such misfolded Tg polypeptides are retained in the ER as high mol wt aggregates.

Babesia canis infection in canine-red blood cell-substituted SCID mice

We have developed a mouse model for Babesia canis infection using severe combined immunodeficiency (SCID) mice whose circulating red blood cells had been substituted with canine red blood cells. Substitution of red blood cells in SCID mice was achieved by repetitive transfusions of canine red blood cells, together with administration of an antimouse red blood cell monoclonal antibody. Following inoculation of canine-red blood cell-SCID mice with B. canis, parasites proliferated in the canine red blood cells that had been transfused into the SCID mice, resulting in much higher parasitaemia than that observed in dogs. In an attempt to demonstrate the utility of this mouse model, three antiprotozoal drugs, diminazene diaceturate, clindamycin and oxytetracycline, were examined for their efficacy to inhibit the growth of B. canis in canine-red blood cell-SCID mice. The mouse model clearly showed that diminazene diaceturate and oxytetracycline were capable of eliminating B. canis from the canine-red blood cell-SCID mice, whereas clindamycin exhibited only a static effect as parasitaemia relapsed upon cessation of drug administration.

Mechanosensitive cation channels mediate afferent arteriolar myogenic constriction in the isolated rat kidney

1. In order to assess ionic mechanisms mediating renal afferent arteriolar myogenic constriction, experiments were performed using isolated perfused hydronephrotic rat kidneys. 2. Increasing pressure progressively constricted the afferent arteriole (-0.26 +/- 0.02% mmHg-1, n = 21, r = 0.97). Gadolinium (10 microM), a mechanosensitive cation channel blocker, abolished this myogenic constriction. However, high potassium media (30 mM) constricted the afferent arteriole in the presence of gadolinium. 3. Lowering extracellular sodium concentration gradually attenuated afferent arteriolar myogenic constriction. In the perfusate containing 50 mM sodium, the myogenic response was arrested. 4. Afferent arteriolar myogenic constriction was prevented in calcium-free perfusate or by the L-type calcium channel blocker diltiazem (10 microM). 5. Our present findings provide evidence that increasing pressure gates mechanosensitive cation channels on the afferent arteriole, thereby eliciting membrane depolarization and activating voltage-dependent calcium channels.

Sequence analysis of thyroid transcription factor-1 gene reveals absence of mutations in patients with thyroid dysgenesis but presence of polymorphisms in the 5' flanking region and intron

Congenital hypothyroidism is caused by several mechanisms. The most common cause worldwide is iodine deficiency, but in iodine-sufficient regions thyroid dysgenesis is the most common cause of congenital hypothyroidism. In the present study we analyzed the thyroid transcription factor-1 (TTF-1) gene in patients with congenital hypothyroidism due to thyroid dysgenesis: three patients with athyrosis, five with ectopy, and one with hypoplasia. Genomic DNA was isolated from peripheral leukocytes, and the TTF-1 gene, including a 5' flanking region, two exons and one intron was amplified by polymerase chain reaction (PCR) with 4 pairs of primers. The PCR products were directly sequenced by the Dye Terminator Cycle Sequencing method. We could not find any mutations specific for the thyroid dysgenesis in the 5' flanking region, two exons and one intron in the TTF-1 gene, but two heterozygous nucleotide substitutions were detected in the intron: a G to A transition at nucleotide 469 (G469A) and a C to A transversion at nucleotide 866 (C866A). The same nucleotide changes were detected in some normal subjects. Allelic frequencies of the polymorphisms G469A and C866A were 23% and 10%, respectively. Another normal polymorphism in the 5' flanking region was a G to T transversion at nucleotide -845 from the transcription start site (G-845T). The allelic frequency of the polymorphism G-845T was 28%. We also found 12 polymorphisms in the 5' flanking region, two in the intron and one in the 3' untranslated region. These polymorphisms were detected in 100% chromosomes. These results suggest that congenital hypothyroidism associated with thyroid dysgenesis is unlikely to be caused by mutations in the TTF-1 gene in which, however, were detected normal polymorphisms in the 5' flanking region, intron and 3' untranslated region.

Unilateral exophthalmos due to orbital metastasis from a contralateral intraocular melanoma

Progressive, left exophthalmos developed due to a left, retrobulbar mass in a 76-year-old Japanese woman. An open tumor biopsy was carried out, and both macro- and microscopic findings of the mass confirmed that it was a malignant melanoma. Orbital melanomas usually result from distant metastasis of cutaneous melanomas or from secondary extension of ipsilateral intraocular melanomas. Thorough physical, laboratory, and radiological examination, however, did not disclose any primary cutaneous or visceral melanoma, nor had the patient any previous history of excision or spontaneous regression of a pigmented lesion. Histopathologically, the left retrobulbar melanoma was rich in sinusoidal vessels which were surrounded by melanoma cells, oriented in a perpendicular array, a histological feature more characteristic of uveal melanomas than of cutaneous ones. The ophthalmological examination excluded development of a primary intraocular melanoma on the left side. Fundoscopic examination of the right eye was not feasible because of the complete opacity of the right vitreous body which had resulted from previous episode of idiopathic vitreous hemorrhage. Unexpectedly, CT and MR studies depicted retrobulbar masses of non-homogeneous densities in the bilateral orbits. These radiologic studies indicated the metastatic nature of the left retrobulbar melanoma, while suggesting the development of a primary, intraocular melanoma on the right side, extension into the right orbit, and involvement of the right optic nerve. All these clinical, radiological, and histological data suggested the development of a primary melanoma in the right eye and subsequent metastasis to the left orbit producing exophthalmos. The mechanism of such a peculiar mode of metastasis remains entirely unknown. This is a rare case of metastatic orbital melanoma, without visceral involvement, which originated in the contralateral eye. Development of the right ocular melanoma remained unrecognized due to atrophic degeneration of the right eyeball and complete opacity of the right vitreous body, until the contralateral orbital metastasis grew massive enough to cause exophthalmos.

Interleukin (IL)-1 and IL-4 synergistically stimulate NF-IL6 activity and IL-6 production in human mesangial cells

BACKGROUND

While interleukin (IL)-4 inhibits pro-inflammatory cytokine expression by human monocytes, we have observed that it potentiates IL-6 production by IL-1-activated human mesangial cells (MC). To study the mechanism of this cell-type specific interaction between IL-1 and IL-4 in MC, we examined the effect of both cytokines on the activities of nuclear factor kappa B (NF-kappa B) and nuclear IL-6 NL-IL 6), transcription factors that are essential for IL-6 gene expression.

METHODS

We evaluated IL-6 synthesis, mRNA expression, and mRNA stability by ELISA, Northern analysis, and the actinomycin D method, respectively. Activities of NF-kappa B and NF-IL 6 were analyzed by gel shift assay.

RESULTS

IL-4 augmented the IL-1 stimulated IL-6 mRNA levels by about threefold without altering mRNA stability. IL-1 treatment rapidly induced the binding activity of NF-kappa B. In contrast, IL-4 did not affect basal and IL-1-induced NF-kappa B activities. Both IL-1 and IL-4 stimulated NF-IL6 activity as early as 30 minutes after treatment. When MC were treated with both cytokines together, marked activation of NF-IL6 was observed at five hours.

CONCLUSIONS

These results suggest that simultaneous activation of NF-kappa B and NF-IL6 is essential for IL-6 gene expression and that IL-1 and IL-4 cooperatively stimulate MC IL-6 production through their synergistic activation of NF-IL6.

Cytoplasmic sequestration of the polyomavirus enhancer binding protein 2 (PEBP2)/core binding factor alpha (CBFalpha) subunit by the leukemia-related PEBP2/CBFbeta-SMMHC fusion protein inhibits PEBP2/CBF-mediated transactivation

The polyomavirus enhancer binding protein 2 (PEBP2)/core binding factor (CBF) is a transcription factor composed of two subunits, alpha and beta. The gene encoding the beta subunit is disrupted by inv(16), resulting in the formation of a chimeric protein, beta-SMMHC, which is associated with acute myelogenous leukemia. To understand the effect of beta-SMMHC on PEBP2-mediated transactivation, we used a luciferase assay system in which contribution of both the alpha and beta subunits was absolutely required to activate transcription. Using this system, we found that the minimal region of the beta subunit required for transactivation resides between amino acid 1 and 135, which is known to dimerize with the alpha subunit. In contrast, beta-SMMHC, despite having this minimal region for dimerization and transactivation, failed to support transcription with the alpha subunit. Furthermore beta-SMMHC blocked the synergistic transcription achieved by PEBP2 and CCAAT/enhancer binding protein alpha. By using a construct in which the PEBP2 alpha subunit was fused to the glucocorticoid receptor ligand binding domain, we demonstrated that coexpressed beta-SMMHC tightly sequestered the alpha subunit in the cytoplasm and blocked dexamethasone-dependent nuclear translocation of the alpha subunit. Thus, the result suggess that beta-SMMHC inhibits PEBP2-mediated transcription via cytoplasmic sequestration of the alpha subunit. Lastly proliferation of ME-1 cells that harbor inv(16) was blocked by an antisense oligonucleotide complementary to the junction of the chimeric mRNA, suggesting that beta-SMMHC contributes to leukemogenesis by blocking the differentiation of myeloid cells.

Missense mutation (C1263R) in the thyroglobulin gene causes congenital goiter with mild hypothyroidism by impaired intracellular transport

Metabolic abnormalities in thyroid hormonogenesis cause congenital goiter. Here we studied a case of mild hypothyroidism caused by a novel missense mutation in the thyroglobulin (TG) gene. A female patient underwent thyroidectomy twice at the age of 27 and 43 years because of gradual enlargement of the thyroid. By RNase cleavage assay and PCR direct sequencing we identified a thymine to cytosine transition at nucleotide 3828 (from the transcription start site) which causes amino acid change from cysteine to arginine at codon 1263. A pedigree study suggested autosomal recessive inheritance due to consanguineous marriage of her parents. Immunohistochemical study suggested impaired intracellular transport of the mutant TG. Sensitivity to endoglycosidase H confirmed that the mutant TG failed to reach the Golgi compartment. Native polyacrylamide gel electrophoresis and Western blot analyses showed that formation of monomers and homodimers was defective with abundant high molecular-weight aggregates which are normally formed transiently after translation. To examine if the mutant TG is functionally defective, we separated thyroid tissue extract on a Biogel A5m column and measured T4 and T3 released from proteins in each fraction by treatment with proteinase K. Although thyroid hormones released per mole of the mutant TG protein did not decrease, those released per mg of total protein decreased. In conclusion, the missense mutation in the TG gene caused congenital goiter with mild hypothyroidism due to an altered protein structure which resulted in defective intracellular processing and premature degradation by "quality control" mechanisms. Although the tissue TG content was greatly reduced, the hypothyroidism was mild with slow progression of the goiter, because the mutant TG was a relatively good substrate for the synthesis of the thyroid hormones.

Intrinsic transcriptional activation-inhibition domains of the polyomavirus enhancer binding protein 2/core binding factor alpha subunit revealed in the presence of the beta subunit

A member of the polyomavirus enhancer binding protein 2/core binding factor (PEBP2/CBF) is composed of PEBP2 alphaB1/AML1 (as the alpha subunit) and a beta subunit. It plays an essential role in definitive hematopoiesis and is frequently involved in the chromosomal abnormalities associated with leukemia. In the present study, we report functionally separable modular structures in PEBP2 alphaB1 for DNA binding and for transcriptional activation. DNA binding through the Runt domain of PEBP2 alphaB1 was hindered by the adjacent carboxy-terminal region, and this inhibition was relieved by interaction with the beta subunit. Utilizing a reporter assay system in which both the alpha and beta subunits are required to achieve strong transactivation, we uncovered the presence of transcriptional activation and inhibitory domains in PEBP2 alphaB1 that were only apparent in the presence of the beta subunit. The inhibitory domain keeps the full transactivation potential of full-length PEBP2 alphaB1 below its maximum potential. Fusion of the transactivation domain of PEBP2 alphaB1 to the yeast GAL4 DNA-binding domain conferred transactivation potential, but further addition of the inhibitory domain diminished the activity. These results suggest that the activity of the alpha subunit as a transcriptional activator is regulated intramolecularly as well as by the beta subunit. PEBP2 alphaB1 and the beta subunit were targeted to the nuclear matrix via signals distinct from the nuclear localization signal. Moreover, the transactivation domain by itself was capable of associating with the nuclear matrix, which implies the existence of a relationship between transactivation and nuclear matrix attachment.

Renal protective effects of efonidipine in partially nephrectomized spontaneously hypertensive rats

We investigated the effects of a calcium antagonist, efonidipine, which was reported to dilate not only afferent arterioles but also efferent alterioles, on progression of renal failure in salt-loaded partially nephrectomized spontaneously hypertensive rats (SHR). Forty-four SHR's with 5 of 6 nephrectomy were divided into four groups: group 1 as control (n=20); group 2, efonidipine-treated (n=8); group 3, enalapril-treated (n=8); and group 4, nifedipine-treated (n=8). The rats were given these drugs and a high-salt diet (5% NaCl) for 8 weeks. During the experiment, systolic blood pressure (SBP) and daily urinary protein excretion were measured every 2 weeks. At the end of the study, serum creatinine was determined, and renal tissues were obtained for light microscopic examination. SBP was markedly reduced by 8-week antihypertensive treatment. (control, 267+/-7 mmHg; efonidipine, 181+/-7 mmHg; enalapril, 200+/-12 mmHg; nifedipine, 184+/-6 mmHg). Glomerular sclerosis developed markedly in the control group, but was partially prevented in all treated groups. Similarly, urinary protein excretion (UPE) was suppressed by efonidipine (180+/-16 mg/day) and enalapril (186+/-16 mg/day vs. 301+/-28 mg/day for control). In contrast, nifedipine failed to prevent the increase in urinary protein excretion (258+/-22 mg/day). In conclusion, efonidipine attenuates SBP increase and ameliorates glomerular injury as well as nifedipine and enalapril. Furthermore, beneficial effects of efonidipine, but not nifedipine, on proteinuria suggest that different mechanisms mediate the improvement of proteinuria; one possible mechanism could be efferent arteriolar dilation, not reported in nifedipine.

Analysis of the promoter of the thyrotropin receptor gene and the entire genomic sequence of thyroid transcription factor-1 in familial congenital hypothyroidism due to thyrotropin unresponsiveness

We previously reported that our patients with congenital primary hypothyroidism associated with thyrotropin (TSH) unresponsiveness through an autosomal recessive pattern of inheritance did not have mutations in the coding region of the TSH receptor gene. In the current study, we analyzed the promoter of the TSH receptor gene and the entire region of the thyroid transcription factor-1 (TTF-1) gene, including promoter, two exons, and one intron, because expression of the rat TSH receptor gene is reported to be stimulated by the interaction of the promoter of the TSH receptor gene with TTF-1. Screening for mutations was performed by RNase cleavage assay, and the polymerase chain reaction (PCR) products were subsequently sequenced by the automatic sequencer. In the promoter of the TSH receptor gene, a duplication of nucleotides -346 to -330 was detected in one allele, but haplotype analysis of the family demonstrated lack of linkage between the duplication and the TSH unresponsiveness. The same duplication was also observed in some normal subjects. In the TTF-1 gene, we detected a transition (guanine to adenine) in the intron at the minus four position of cryptic 3' splice site in one allele, but absence of linkage suggested that the transition was not responsible for the TSH unresponsiveness. The same transition also was found in some normal subjects. These results suggest that TSH unresponsiveness in our patients is unlikely to be caused by mutations either in the promoter of the TSH receptor gene or in the TTF-1 gene.

Seven zinc-finger transcription factors are expressed sequentially during the development of anthers in petunia

The development of anthers and pollen involves several stages. In an attempt to identify the transcription factors that are involved in the regulation of gene expression associated with the development of anthers, seven genes for new zinc-finger proteins that are expressed in anthers were detected using RT-PCR. Subsequent cloning and sequence analysis of the full-length cDNA clones revealed that they all encoded zinc-finger proteins of the EPF type. However, the encoded proteins were very different from each other in terms of size, number of zinc fingers (two, three and four) and the spacings between the fingers. Northern blot analysis revealed that the genes were expressed preferentially in anthers. Moreover, it was found that the seven genes were expressed transiently for short periods that corresponded to different developmental stages. It appeared that the genes were activated sequentially during the development of the anther. Considering these observations, a possible mechanism that could account for the autonomous progression of the development of the anther via a regulatory cascade of these transcription factors is discussed.

Cys2/His2 zinc-finger protein family of petunia: evolution and general mechanism of target-sequence recognition

The EPF family is a group of Cys2/His2zinc-finger proteins in petunia. In these proteins, characteristically long spacer regions have been found to separate the zinc fingers. Our previous DNA-binding studies demonstrated that two-fingered proteins (ZPT2-1 and ZPT2-2), which have spacers of different lengths, bind to two separate AGT core motifs in a spacing specific manner. To investigate the possibility that these proteins might distinguish between the target sequences on the basis of spacing between the core motifs, we screened petunia cDNA library for other proteins belonging to this family. Initial screening by PCR and subsequent cloning of full-length cDNAs allowed us to identify the genes for 10 new proteins that had two, three or four zinc fingers. Among the two-fingered proteins the spacing between zinc fingers varied from 19 to 65 amino acids. The variation in the length of spacers was even more extensive in three- and four-fingered proteins. The presence of such proteins is consistent with our hypothesis that the spacing between the core motifs might be important for target sequence recognition. Furthermore, comparison of diverse protein structures suggests that three- and two-fingered proteins might have resulted due to successive loss of fingers from a four-fingered protein during molecular evolution. We also demonstrate that a highly conserved motif (QALGGH) among the members of EPF family and other Cys2/His2 zinc-finger proteins in plants is critical for the DNA-binding activity.

Clinical significance of hepatitis G virus infection in patients on long-term haemodialysis

Infection with the newly discovered hepatitis G virus (HGV) was analysed in 163 patients on long-term haemodialysis to clarify its prevalence and clinical significance. Hepatitis G virus RNA in serum was measured by polymerase chain reaction with primers corresponding to the putative non-structural 5' region. Of the 163 patients, three (1.8%) were positive for hepatitis B surface antigen, 40 (24.5%) were positive for hepatitis C virus (HCV)-RNA and 16 (9.8%) were positive for HGV-RNA. Five of the 16 patients with HGV-RNA were also positive for HCV-RNA. Patients with HCV and HGV coinfection had undergone a longer duration of haemodialysis (P = 0.001) and had higher units of transfusion (P = 0.031) compared with those without hepatitis virus infection. Transfusion history was significantly higher (P = 0.039) in patients with only HGV infection than in those without hepatitis virus infection. Hepatitis C virus RNA concentration was higher (P = 0.032) in patients with HCV and HGV coinfection than in those with HCV infection only, but alanine aminotransferase (ALT) levels were similar between these two groups. In conclusion, about 10% of patients on haemodialysis were infected with HGV and the infection was closely associated with transfusion history.

Cellular mechanisms mediating rat renal microvascular constriction by angiotensin II

To assess cellular mechanisms mediating afferent (AA) and efferent arteriolar (EA) constriction by angiotensin II (AngII), experiments were performed using isolated perfused hydronephrotic kidneys. In the first series of studies, AngII (0.3 nM) constricted AAs and EAs by 29+/-3 (n = 8, P < 0.01) and 27+/-3% (n = 8, P < 0.01), respectively. Subsequent addition of nifedipine restored AA but not EA diameter. Manganese (8 mM) reversed EA constriction by 65+/-9% (P < 0.01). In the second group, the addition of N-ethylmaleimide (10 microM), a Gi/Go protein antagonist, abolished AngII- induced EA (n = 6) but not AA constriction (n = 6). In the third series of experiments, treatment with 2-nitro-4-carboxyphenyl-N, N-diphenyl-carbamate (200 microM), a phospholipase C inhibitor, blocked both AA and EA constriction by AngII (n = 6 for each). In the fourth group, thapsigargin (1 microM) prevented AngII-induced AA constriction (n = 8) and attenuated EA constriction (8+/-2% decrease in EA diameter at 0.3 nM AngII, n = 8, P < 0.05). Subsequent addition of manganese (8 mM) reversed EA constriction. Our data provide evidence that in AAs, AngII stimulates phospholipase C with subsequent calcium mobilization that is required to activate voltage-dependent calcium channels. Our results suggest that AngII constricts EAs by activating phospholipase C via the Gi protein family, thereby eliciting both calcium mobilization and calcium entry.

A novel transcript encoding an N-terminally truncated AML1/PEBP2 alphaB protein interferes with transactivation and blocks granulocytic differentiation of 32Dcl3 myeloid cells

The gene AML1/PEBP2 alphaB encodes the alpha subunit of transcription factor PEBP2/CBF and is essential for the establishment of fetal liver hematopoiesis. Rearrangements of AML1 are frequently associated with several types of human leukemia. Three types of AML1 cDNA isoforms have been described to date; they have been designated AML1a, AML1b, and AML1c. All of these isoforms encode the conserved-Runt domain, which harbors the DNA binding and heterodimerization activities. We have identified a new isoform of the AML1 transcript, termed AML1 deltaN, in which exon 1 is directly connected to exon 4 by alternative splicing. The AML1 deltaN transcript was detected in various hematopoietic cell lines of lymphoid to myeloid cell origin, as revealed by RNase protection and reverse transcriptase PCR analyses. The protein product of AML1 deltaN lacks the N-terminal region of AML1, including half of the Runt domain, and neither binds to DNA nor heterodimerizes with the beta subunit. However, AML1 deltaN was found to interfere with the transactivation activity of PEBP2, and the molecular region responsible for this activity was identified. Stable expression of AML1 deltaN in 32Dcl3 myeloid cells blocked granulocytic differentiation in response to granulocyte colony-stimulating factor. These results suggest that AML1 deltaN acts as a modulator of AML1 function and serves as a useful tool to dissect the functional domains in the C-terminal region of AML1.

Retroviral infection in peripheral mononuclear cells in patients with IgA nephropathy

An etiologic agent directly linked to the development of IgA nephropathy (IgAN) has not been identified, despite the fact that various causes, including viral infections, have been implicated in the pathogenesis of this disease. Human immunodeficiency virus (HIV) infection has been linked with the development of IgAN in several clinical studies, and retroviral infection may be associated with the pathogenesis of IgAN in some patients. The incidence of IgAN has been found to possess distinct geographical distributions, and familial genetic clustering. To determine if retroviral infection is associated with IgAN in a large population of patients, genomic DNA from peripheral blood mononuclear cells from 90 patients seronegative for HIV and human T-cell leukemia virus type 1 (HTLV-1) (37 IgAN, 33 other glomerulonephritis, and 20 healthy controls) was evaluated by nested PCR using a pan-lentivirus-specific primer set (PLSPS), targeting the consensus sequence of the lentiviral pol gene. In 37.8% (14 of 37) of the patients with IgAN, the PCR products migrated in parallel with bands produced by PCR of simian immunodeficiency virus (SIV) infected cells. No products of the expected size were detected in the other patient groups (p < 0.0001, Chi-square). These results suggest that exposure to retroviral infection is more common in patients with IgAN, compared with patients with other proliferative glomerulonephritides, or patients without renal disease. These data demonstrate a possible association of IgAN with infection with non-HIV, non-HTLV-1 retrovirus.

Hemodialysis-related arthropathy. A prospective MR study with SE and GRE sequences

PURPOSE

A prospective examination of hemodialysis-related arthropathy by MR imaging with SE and GRE sequences was undertaken to verify whether the low signal intensity on T2-weighted SE images is caused by a paramagnetic susceptibility effect derived from amyloid or from hemosiderin.

MATERIAL AND METHODS

Twenty-seven joints (19 hip joints, 6 discovertebral joints of 5 lumbosacral spines and 1 cervical spine, 2 shoulder joints) in 14 patients undergoing long-term hemodialysis (duration 10-22 years, mean 17) were examined with SE T1-weighted, T2-weighted and GRE T2*-weighted sequences.

RESULTS

The signal intensity of the intraarticular and periarticular masses of the involved joints was basically isointense to the muscle in all 3 pulse sequences. No significantly low signal area was found on GRE T2*-weighted images.

CONCLUSION

The low signal areas in the hemodialysis-related arthropathy on SE T2-weighted images are not caused by a paramagnetic susceptibility effect, but probably by the hypocellular and fibrous nature of amyloid-containing tissues. Therefore the GRE sequence can be helpful for differentiating hemodialysis-related amyloid arthropathy from chronic hemarthrosis or juxta-articular brown tumor.

A dominant negative mutant of an IFN regulatory factor family protein inhibits both type I and type II IFN-stimulated gene expression and antiproliferative activity of IFNs

Type I (alpha,beta) and type II (gamma) IFNs elicit antiproliferative and antiviral activities through two distinct transcription pathways involving 1) IRF family proteins and ISGF3, and 2) STAT1. We have employed a dominant negative strategy to study the role of IRF family proteins in eliciting the biologic activities of IFN. A truncated IRF protein retaining the DNA-binding domain (DBD) of ICSBP (a member of the IRF family) was stably transfected into U937 monocytic cells. Clones expressing DBD had markedly reduced ISRE-binding activity and were defective in expressing several type I IFN-inducible genes. STAT1 was one such type I IFN-inducible gene whose expression was also inhibited in DBD clones. As a result, the expression of several IFN-gamma-inducible genes was also inhibited in these clones, indicating functional coupling of the type I and type II IFN transcription pathways. Furthermore, DBD clones grew more slowly than control clones and were refractory to antiproliferative effects of both types of IFNs. We found that IFN treatment of U937 cells leads to a G1 arrest and an increase in underphosphorylated retinoblastoma gene product. However, IFN treatment did not change the cell cycle profile, nor retinoblastoma gene product phosphorylation state in DBD clones. These data indicate that expression of DBD disrupts cell cycle regulatory mechanisms. Combined with the previously noted failure of DBD clones to elicit antiviral activity, the present work shows that IRF family proteins play an integral part in growth control activities of IFNs.

A dominant negative mutant of an IFN regulatory factor family protein inhibits both type I and type II IFN-stimulated gene expression and antiproliferative activity of IFNs

Type I (alpha,beta) and type II (gamma) IFNs elicit antiproliferative and antiviral activities through two distinct transcription pathways involving 1) IRF family proteins and ISGF3, and 2) STAT1. We have employed a dominant negative strategy to study the role of IRF family proteins in eliciting the biologic activities of IFN. A truncated IRF protein retaining the DNA-binding domain (DBD) of ICSBP (a member of the IRF family) was stably transfected into U937 monocytic cells. Clones expressing DBD had markedly reduced ISRE-binding activity and were defective in expressing several type I IFN-inducible genes. STAT1 was one such type I IFN-inducible gene whose expression was also inhibited in DBD clones. As a result, the expression of several IFN-gamma-inducible genes was also inhibited in these clones, indicating functional coupling of the type I and type II IFN transcription pathways. Furthermore, DBD clones grew more slowly than control clones and were refractory to antiproliferative effects of both types of IFNs. We found that IFN treatment of U937 cells leads to a G1 arrest and an increase in underphosphorylated retinoblastoma gene product. However, IFN treatment did not change the cell cycle profile, nor retinoblastoma gene product phosphorylation state in DBD clones. These data indicate that expression of DBD disrupts cell cycle regulatory mechanisms. Combined with the previously noted failure of DBD clones to elicit antiviral activity, the present work shows that IRF family proteins play an integral part in growth control activities of IFNs.

Immunodeficiency and chronic myelogenous leukemia-like syndrome in mice with a targeted mutation of the ICSBP gene

Interferon consensus sequence binding protein (ICSBP) is a transcription factor of the interferon (IFN) regulatory factor (IRF) family. Mice with a null mutation of ICSBP exhibit two prominent phenotypes related to previously described activities of the IRF family. The first is enhanced susceptibility to virus infections associated with impaired production of IFN(gamma). The second is deregulated hematopoiesis in both ICSBP-/- and ICSBP+/- mice that manifests as a syndrome similar to human chronic myelogenous leukemia. The chronic period of the disease progresses to a fatal blast crisis characterized by a clonal expansion of undifferentiated cells. Normal mice injected with cells from mice in blast crisis developed acute leukemia within 6 weeks of transfer. These results suggest a novel role for ICSBP in regulating the proliferation and differentiation of hematopoietic progenitor cells.

Role of chloride channels in afferent arteriolar constriction

The effects of IAA-94, a chloride channel blocker and/or low chloride perfusate on afferent arteriolar (AA) constriction by angiotensin II (Ang II), norepinephrine (NE) and increasing pressure (80 to 160 mm Hg) were assessed using isolated perfused hydronephrotic kidneys. In the first series of experiments, Ang II (0.3 nM) constricted AAs by 33 +/- 3% (N = 5, P < 0.01). Subsequent addition of diltiazem (10 microM) restored the decrements in the AA diameters. In the presence of diltiazem (10 microM), increasing pressure did not constrict AAs. In the second series of experiments. elevation of pressure constricted AAs by 20 +/- 2% (N = 7. P < 0.01). Subsequent addition of IAA-94 (30 microM) failed to alter the basal AA diameter and myogenic responsiveness. However, Ang II-induced AA constriction was abolished by IAA-94. In the third series of experiments, decreasing extracellular chloride exaggerated AA constriction by 0.1 nM of Ang II (from 13 +/- 2 to 20 +/- 3%, N = 6, P < 0.05). Similarly, low chloride perfusate enhanced NE (0.1 microM)-induced AA constriction (from 14 +/- 2 to 19 +/- 2%, N = 6, P < 0.05). In contrast, myogenic responsiveness was not influenced by reducing chloride concentrations. The present data provide evidence that both Ang II and NE induce AA constriction by opening chloride channels and subsequent activation of voltage-dependent calcium channels, and suggest that the myogenic response is mediated by activating voltage-dependent calcium channels independently of chloride channels.

Antihypertensive agents and renal protection: calcium channel blockers

This study defines the nature of the renal protective effects of calcium channel blockers (Ca blockers) and the effects of the Ca blocker, amlodipine, compared to those of the angiotensin-converting enzyme inhibitor (ACEI), enalapril, on the progression of renal injury in 5/6 nephrectomized spontaneously hypertensive rats (SHR) fed a high-salt diet. Furthermore, we studied the effects of various Ca blockers on the glomerular afferent and efferent arterioles using the isolated perfused hydronephrotic kidneys of six-week-old male Sprague-Dawley rats. In the first study, forty 6-week-old male SHRs which underwent 5/6 nephrectomy were equally divided into five groups. One group received no therapy. In two groups, therapy was started at four weeks post-nephrectomy, one with amlodipine and the other with enalapril. In the remaining two groups, amlodipine or enalapril therapy was started at eight weeks postnephrectomy. Amlodipine was more effective than enalapril in reducing proteinuria and glomerulosclerosis in the group that was started on drug therapy eight weeks after surgery. In the second study, at concentrations of 10(-6) to 10(-9) M, nifedipine, nicardipine and amlodipine dilated the afferent, but not the efferent, arteriole preconstricted with angiotensin II. On the other hand, efonidipine and manidipine clearly dilated angiotensin II-induced constriction of both the afferent and efferent arterioles. These results indicated that Ca blockers are effective at reducing renal injury in 5/6 nephrectomized SHR, and that they are more effective than ACEI in advanced stages of renal injury. The observation that only certain Ca blockers can dilate the efferent arteriole suggests that the renal protective effect of Ca blockers is not necessarily dependent on the dilation of the efferent arterioles.

Sodium balance and hypertension in obese and fatty rats

To investigate the role of sodium in obesity induced hypertension, Wistar fatty rats (WFR) were employed. This rat has the following characteristics: (1) hyperglycemia, (2) hyperinsulinemia, and (3) hypertriglycemia. Four percent sodium chloride with constant amount of food intake was administered to these rats from 8 to 16 weeks. During this period, body wt, food intake, water consumption, urine volume, systolic blood pressure, urinary excretion of sodium and potassium, urinary albumin excretion, plasma sodium and potassium, and plasma glucose and immunoreactive insulin (IRI) were measured before, and twice more during eight weeks. No remarkable changes were observed in plasma glucose level during these periods between the two groups. On the other hand, in group 1 IRI significantly increased compared with group 2. Mean blood pressure was increased from 110 +/- 5 to 130 +/- 8 mm Hg (P < 0.01). To ascertain whether this salt sensitivity relates to the abnormalities in pressure-natriuresis responses, the pressure-natriuresis (P-N) was characterized. The P-N curve in WFR was shifted to the right and its slope was flattened compared to its control Wistar lean rats. In conclusion, an excess of dietary sodium intake may contribute to an elevation of blood pressure in Wistar fatty rat with hyperglycemia and hyperinsulinemia. This salt sensitivity may change the abnormal pressure-natriuresis responses.

Expression of IFN regulatory factor family proteins in lymphocytes. Induction of Stat-1 and IFN consensus sequence binding protein expression by T cell activation

Interferon consensus sequence binding protein (ICSBP) is a transcription factor of the IFN regulatory factor (IRF) family. Evidence indicates that this family has a function in the immune system. Unlike other members of the family, ICSBP is expressed exclusively in the immune system. In this work, immunoblot analysis was performed to study expression of ICSBP and other members of the family in various murine lymphocytes. The results show that all IRF family members are expressed constitutively in B cells throughout development, and in resting and activated cells. In contrast, ICSBP expression was undetectable in thymocytes and resting T cells, while all other IRF proteins tested (IRF-1, IRF-2, and ISGF3-gamma) were detected in these cells. Induction of ICSBP (and weakly IRF-1, but not other members) was observed upon activation of T cells following anti-CD3 Ab binding or Con A stimulation. Once T cells were activated, ICSBP was expressed stably in both Th1 and Th2 cells. We show that Stat-1, which binds to the IFN-gamma-responsive element of the ICSBP promoter, was induced following anti-CD3 Ab and Con A stimulation. Stat-1 induction was found in T cells of IFN-gamma+/+, but not of IFN-gamma-/- mice, indicating that T cell activation stimulates the Stat pathway of transcription that is mediated through IFN-gamma. IFN-gamma-activated Stat-1 partly accounted for ICSBP induction in activated T cells, as levels of induction were lower in IFN-gamma-/- than in IFN+/+ T cells. Taken together, these results show that activation of ICSBP is coupled with T cell activation that is partly due to IFN-gamma-induced Stat-1.

Expression of IFN regulatory factor family proteins in lymphocytes. Induction of Stat-1 and IFN consensus sequence binding protein expression by T cell activation

Interferon consensus sequence binding protein (ICSBP) is a transcription factor of the IFN regulatory factor (IRF) family. Evidence indicates that this family has a function in the immune system. Unlike other members of the family, ICSBP is expressed exclusively in the immune system. In this work, immunoblot analysis was performed to study expression of ICSBP and other members of the family in various murine lymphocytes. The results show that all IRF family members are expressed constitutively in B cells throughout development, and in resting and activated cells. In contrast, ICSBP expression was undetectable in thymocytes and resting T cells, while all other IRF proteins tested (IRF-1, IRF-2, and ISGF3-gamma) were detected in these cells. Induction of ICSBP (and weakly IRF-1, but not other members) was observed upon activation of T cells following anti-CD3 Ab binding or Con A stimulation. Once T cells were activated, ICSBP was expressed stably in both Th1 and Th2 cells. We show that Stat-1, which binds to the IFN-gamma-responsive element of the ICSBP promoter, was induced following anti-CD3 Ab and Con A stimulation. Stat-1 induction was found in T cells of IFN-gamma+/+, but not of IFN-gamma-/- mice, indicating that T cell activation stimulates the Stat pathway of transcription that is mediated through IFN-gamma. IFN-gamma-activated Stat-1 partly accounted for ICSBP induction in activated T cells, as levels of induction were lower in IFN-gamma-/- than in IFN+/+ T cells. Taken together, these results show that activation of ICSBP is coupled with T cell activation that is partly due to IFN-gamma-induced Stat-1.

Interleukin-4 modulates collagen synthesis by human mesangial cells in a type-specific manner

Several studies have suggested an involvement of interleukin (IL)-4 in the pathophysiology of glomerulonephritis (GN). To elucidate its possible role in GN, we have investigated the effect of IL-4 on collagen accumulation by human mesangial cells (MC). After incubation with IL-1 alpha and/or IL-4 for 48 h, type I, III, and IV collagens in both soluble and cell-associated forms were identified by Western blotting. IL-1 alpha stimulated type I and IV collagen synthesis, lacking significant effect on type III collagen synthesis. In contrast, IL-4 stimulated type III collagen synthesis without affecting type I and type IV synthesis. Enzyme-linked immunosorbent assay confirmed the dose-dependent effect of IL-4 on collagen type III secretion (2.0-fold at 10 ng/ml). Importantly, IL-1 alpha-stimulated type I and IV collagen synthesis was suppressed by concomitant IL-4 treatment. Northern analysis of type I and III procollagen mRNAs displayed consistent results. These data indicate that IL-4 selectively stimulates type III collagen synthesis but also suppresses IL-1 alpha-stimulated type I and IV collagen synthesis. Therefore IL-4 could potentially contribute to the pathological changes in glomerular diseases in cooperate with other cytokines.

Does combined therapy of Ca-channel blocker and angiotensin converting enzyme inhibitor exceed monotherapy in renal protection against hypertensive injury in rats?

Either calcium channel blocker (CCB) or angiotensin converting enzyme inhibitor (ACEi) is used as an antihypertensive agent, and we are recommended to use them in combination to refractory hypertension with evidence dependent on clinical observations. We examined the renal protective effect of the combined therapy with calcium channel blocker (amlodipine) and angiotensin converting enzyme inhibitor (enalapril) against hypertensive renal injury in 5/6 nephrectomized spontaneously hypertensive rats (SHRs) with salt loading, comparing with monotherapy of each drug. Forty males SHRs with 5/6 nephrectomy and salt loading were divided to five groups: group 1 as control (n = 8), group 2 received 0.2 mg/kg/day of amlodipine (n = 8), group 3 received 0.2 mg/kg/day of enalapril (n = 8), group 4 (n = 8) and group 5 (n = 8) that were treated with 0.1 mg/kg/day and 0.2 mg/kg/day of each drug in combination respectively. Either amlodipine or enalapril had remarkable effects on reducing the increases in blood pressure and urinary protein excretion. In histopathological examination, it also suppressed renal injury significantly. Additional significant effect of combined therapy was not observed in blood pressure and urinary protein. There were not remarkable, additional effects of the combination of CCB and ACEi on protecting the remnant kidney in 5/6 nephrectomized SHRs fed a high-salt diet, possibly because sodium retention was not alleviated by the combination.

Evidence for the involvement of vasopressin in the pathophysiology of adriamycin-induced nephropathy in rats

The effect of orally available, nonpeptide vasopressin V1 and V2 receptor antagonists on chronic progressive glomerular disease was investigated in Wistar rats with Adriamycin-induced nephropathy. At weeks 0 and 3, Adriamycin was injected twice, and at week 3 drugs started to be given as follows: groups 2 and 3 were treated with V1 and V2 antagonists, respectively, while the untreated group 1 served as control. To block the effects of vasopressin totally, both V1 and V2 antagonists were simultaneously administered (group 4). At weeks 8 and 10, V1 and V2 antagonists given either alone or combined significantly reduced the urinary protein excretion to the same levels. Urinary volume increased in groups 3 and 4 from week 4. Systolic blood pressure did not significantly increase in all groups during the study. Histological alterations in the kidney of groups 2, 3 and 4 were significantly attenuated compared to the control. These results suggest that both vasopressin V1 and V2 agonism plays a role in the pathophysiology of Adriamycin-induced nephropathy despite plasma levels of vasopressin within the normal range. These findings also lead to the notion that in some types of nephrotic patients these orally available V1 and/or V2 receptor antagonists may be effective for reduction of proteinuria and for retardation of progression of renal failure.

Calcium channel blockers versus ACE inhibitors as antihypertensives in polycystic kidney disease

The effects of calcium channel blockers (CCBs) and angiotensin converting enzyme (ACE) inhibitors on blood pressure and the progression of renal dysfunction were compared in hypertensive patients with polycystic kidney disease (PKD). Twenty-six patients with PKD and hypertension who had been treated with other antihypertensive agents, such as diuretics, beta-blockers, or alpha-methyldopa, were followed up for two years, during which their blood pressure and renal function were monitored. Patients were divided into two groups classified according to the type of antihypertensive agents given. Group 1 (n = 14) received CCBs, while group 2 (n = 12) received ACE inhibitors. No significant differences were found in their blood pressure control and serum creatinine levels throughout the study. The creatinine clearances were decreased in both groups. However, the decreases in creatinine clearance were smaller (p < 0.05) in the group treated with CCBs. In addition, two patients in group 2 showed rapid increases in serum creatinine. Our data suggest that CCBs reduced blood pressure effectively and preserved renal function in PKD patients at least as well as ACE inhibitors.

Renal responses to angiotensin receptor antagonist and angiotensin-converting enzyme inhibitor in partially nephrectomized spontaneously hypertensive rats

To investigate the role of the renin-angiotensin system (RAS) on nephrosclerosis in salt-loaded, partially nephrectomized spontaneously hypertensive rats (SHR), we evaluated the effects of angiotensin II (ANGII) blockade on the progression of nephrosclerosis with an angiotensin type 1 receptor (AT1rec) antagonist [TCV-116 (TCV)] and an angiotensin-converting enzyme (ACE) inhibitor (enalapril) at the doses equivalent in reducing systemic blood pressure (BP). SHR were five/sixths nephrectomized and were fed a high-salt diet. In addition to being significantly preventive against an increase in systolic BP, both TCV and enalapril significantly attenuated the increases in proteinuria and the renal histopathological alterations. Transcription of AT1rec mRNA in the remnant kidney was enhanced with the progression of nephrosclerosis, but was inhibited by TCV as well as enalapril. In these aspects, there were no apparent differences between effects of TCV and enalapril. The RAS system plays an important role in nephrosclerosis in partially nephrectomized SHR despite a high-salt diet, and direct ANGII blockade certainly protected the kidney against hypertensive injury in this model.

Vesicular stomatitis virus infection induces a nuclear DNA-binding factor specific for the interferon-stimulated response element

Vesicular stomatitis virus (VSV) has a broad host range. It replicates in the cytoplasm and causes rapid cytopathic effects. We show that following VSV infection, a nuclear factor that binds to a select set of interferon-stimulated responsive elements (ISRE) is induced in many cell types. This factor, tentatively called VSV-induced binding protein (VIBP), was estimated to have an approximate molecular mass of 50 kDa and was distinct from known members of the interferon regulatory factor family, that are known to bind to the ISRE. Induction of VIBP required tyrosine kinase activity but did not require cellular transcription. Treatment of cells with cycloheximide, which inhibits translation, only partially inhibited induction of VIBP. However, type I interferons and staurosporine, both of which inhibit VSV transcription, inhibited VIBP induction. Moreover, a double-stranded RNA analog, poly(I)-poly(C) also induced a DNA-binding activity very similar to that of VIBP. These results indicate that a preexisting cellular protein is activated upon VSV infection and that this activation requires primary viral transcripts. The functional activity of VIBP was analyzed in cells stably transfected with a herpesvirus thymidine kinase-luciferase reporter gene that is under control of the ISRE. While activity of the control promoter without ISRE was strongly inhibited following VSV infection (as a result of virus-mediated transcriptional shutdown of the host cell), the inhibition was reversed by the ISRE-containing promoter, albeit partially, which suggests that VSV infection differentially affects transcription of host genes. Although VIBP was induced in all other cells tested, it was not induced in embryonal carcinoma cells after VSV infection, suggesting developmental regulation of VIBP inducibility.

Effects of novel, nonpeptide vasopressin antagonists on progressive nephrosclerosis in rats

Effects of novel, nonpeptide vasopressin V1 and V2 receptor antagonists on partially nephrectomized and salt-loaded spontaneously hypertensive rats (SHR), which develop severe hypertension and progressive nephrosclerosis, were investigated. SHR were 5/6-nephrectomized and fed a high salt diet. The rats were divided into four groups: group 1 was an untreated control, group 2 received the V1 antagonist OPC-21268, group 3 received the V2 antagonist OPC-31260, and group 4 received both the V1 and V2 antagonists. The V1 antagonist alone or combined with the V2 antagonist significantly decreased the increase in blood pressure (BP) of groups 2 and 4 rats, but the V2 antagonist alone did not reduce the increase in BP of the group 3 rats. The V2 antagonist alone or combined with the V1 antagonist induced a significant diuresis of rats in groups 3 and 4. The increase in urinary protein excretion and the progression of renal hyaline arteriolosclerosis were attenuated by the V1 antagonist with or without the V2 antagonist in rats in groups 2 and 4, but not by the V2 antagonist alone in rats in group 3. This implies that the progressive nephrosclerosis in SHR with partial renoablation and salt-loading was associated with V1 agonism.

Relationship among seminal characteristics, fertility and suitability for semen preservation in draft stallions

Seminal characteristics, fertility and the response to semen preservation (liquid storage and cryopreservation) were evaluated in 4 Draft stallions (Percheron 2, Breton 2). Seminal characteristics (gel-free volume, sperm concentration, sperm morphology, percentage of motile spermatozoa) were assessed in 5 ejaculates from each of the 4 stallions. The fertility of the stallions was calculated retrospectively as the accumulated pregnancy rate over 3 breeding seasons. Five ejaculates from each of the stallions were subjected to liquid storage at 5 degrees C. The percentage of motile spermatozoa (PMS) was assessed at 0, 24, 48 and 72 hr. Cryopreservation was done with a glucose-EDTA-lactose egg yolk extender and a skim milk-based extender containing clarified egg yolk (4 replicates per stallion). PMS and the percentage of spermatozoa with an intact plasma membrane (IPM) were evaluated before and after freezing. Although semen characteristics and fertility were within a physiological range, significant differences among stallions were found for gel-free volume, percentage of morphologically normal spermatozoa, PMS, and fertility but there was no clear relationship between these parameters. The response to liquid storage of diluted semen samples differed among stallions and best results were obtained in a stallion with the highest initial motility. The freezability of semen from the 4 stallions was poor with both of the freezing protocols (PMS range 13.8%-26.3%; IPM range 19.5%-38.0%). Results of liquid storage and cryopreservation were not correlated in individual stallions and were not related to their fertility. Since predictability for the response to semen preservation is low, the suitability of individual stallions for semen preservation has to be examined carefully.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of nonpeptide vasopressin receptor antagonists on developing, and established DOCA-salt hypertension in rats

Efficacy of orally available, selective vasopressin V1 and V2 receptor antagonists on the developing and established stage of DOCA-salt hypertension was investigated. Twenty-nine Wistar rats were heminephrectomized, and administered DOCA (50 mg/kg; intraperitoneally twice a week) and salt (5% NaCl diet) from week 0 to the end of study. Group 1 rats were served as control. Group 2 and 5 rats were given a V1 antagonist, and groups 3 and 6 rats were given a V2 antagonist, while groups 4 and 7 rats received both V1 and V2 antagonists. Each drug was started to groups 2, 3 and 4 at week 0, and to groups 5, 6 and 7 at week 4. Significant amelioration of the increase in blood pressure was observed in groups 3 and 4 at week 10, and a reduction in blood pressure occurred in groups 6 and 7 at week 10. Otherwise, a V1 antagonist alone slightly attenuated blood pressure rise in the group 2 without significance, and failed to lower blood pressure of the group 5 during the study. These results suggest that both V1 and V2 agonisms are involved in an increase in blood pressure at the developing stage of DOCA-salt hypertension, and that V2 agonism, but not V1 plays a major role in the maintenance of high blood pressure at the established stage.