A novel detection method for 2'-deoxyoxanosine

2'-Deoxyoxanosine (dOxo) is a novel DNA lesion produced from 2'-deoxyguanosine by the treatment with nitrous acid and nitric oxide. However, there has been no direct evidence on the formation of dOxo in vivo so far. In order to detect dOxo in vivo, we have explored a sensitive detection method specific for dOxo by using a fluorescent labeling reagent and HPLC analysis. An efficient method to detect the dOxo formation in DNA is described.

Expression of nuclear factor of activated T cells mRNA in maternal peripheral blood cells

PROBLEM

In T lymphocytes, nuclear factor of activated T cells (NF-AT) regulates the induction of cytokine genes upon antigenic stimulation. This study was designed to analyse the relationship between NF-AT and pregnancy.

METHOD OF STUDY

With informed consent, peripheral blood cells (PBCs) were obtained from non-pregnant (n = 114), pregnant (n = 604), and puerperal women (n = 52). The expression of NF-AT2 and NF-AT3 mRNAs in PBCs was measured by a quantitative reverse transcriptase-polymerase chain reaction method.

RESULTS

In the early pregnancy period, in successful pregnancy, both NF-AT2 and NF-AT3 mRNAs increased significantly, whereas in cases of spontaneous abortion they did not change significantly. After peaking, they decreased gradually and were re-elevated in the ninth and tenth gestational month. In the puerperal period, NF-AT3 mRNAs decreased, but NF-AT2 mRNA showed a comparatively high expression level.

CONCLUSION

These findings suggested that in humans NF-AT signal transduction might be involved in alloantigenic recognition and tolerance and play important roles, especially in the early and late period of pregnancy.

Sarcoplasmic reticulum Ca2+ release is not a dominating factor in sinoatrial node pacemaker activity

Recent work on isolated sinoatrial node cells from rabbit has suggested that sarcoplasmic reticulum Ca2+ release plays a dominant role in the pacemaker potential, and ryanodine at a high concentration (30 micromol/L blocks sarcoplasmic reticulum Ca2+ release) abolishes pacemaking and at a lower concentration abolishes the chronotropic effect of beta-adrenergic stimulation. The aim of the present study was to test this hypothesis in the intact sinoatrial node of the rabbit. Spontaneous activity and the pattern of activation were recorded using a grid of 120 pairs of extracellular electrodes. Ryanodine 30 micromol/L did not abolish spontaneous activity or shift the position of the leading pacemaker site, although it slowed the spontaneous rate by 18.9+/-2.5% (n=6). After ryanodine treatment, beta-adrenergic stimulation still resulted in a substantial chronotropic effect (0.3 micromol/L isoproterenol increased spontaneous rate by 52.6+/-10.5%, n=5). In isolated sinoatrial node cells from rabbit, 30 micromol/L ryanodine slowed spontaneous rate by 21.5+/-2.6% (n=13). It is concluded that sarcoplasmic reticulum Ca2+ release does not play a dominating role in pacemaking in the sinoatrial node. The full text of this article is available at http://www.circresaha.org.

Endometriosis: the pathophysiology as an estrogen-dependent disease

Endometriosis, defined as the presence of endometrial glands and stroma outside of the uterine cavity, develops mostly in women of reproductive age and regresses after menopause or ovariectomy, suggesting that the growth is estrogen-dependent. Indeed, the lesions contain estrogen receptors (ER) as well as aromatase, an enzyme that catalyses the conversion of androgens to estrogens, suggesting that local estrogen production may stimulate the growth of lesions. The expression patterns of ER and progesterone receptors in endometriotic lesions are different from those in the eutopic endometrium. Moreover, estrogen metabolism, including the expression pattern of aromatase and the regulation of 17 beta-hydroxysteroid dehydrogenase type 2 (an enzyme responsible for the inactivation of estradiol to estrone), is altered in the eutopic endometrium of women with endometriosis, adenomyosis, and/or leiomyomas compared to that in the eutopic endometrium of women without disease. Immunostaining for P450arom in endometrial biopsy specimens diagnosed these diseases with sensitivity and specificity of 91 and 100%, respectively. This is applicable to the clinical diagnosis of endometriosis. The polymorphisms in the ER-alpha gene, the CYP19 gene encoding aromatase, and several other genes are associated with the risk of endometriosis. Studies of these will lead to better understandings of the etiology and pathophysiology of endometriosis.

Postmenopausal hormone replacement therapy use and risk of endometrial cancer in Japanese women

The relationship between the risk of endometrial cancer and the use of noncontraceptive estrogens by Japanese postmenopausal women was investigated in a hospital-based case-control study of 1025 women with endometrial cancer and 1267 with other conditions. The overall odds ratio (OR) for estrogen use with or without progestins, compared with never use of any type of estrogens, was 0.917 (95% confidence interval (CI) 0.622-1.353), suggesting that hormone replacement therapy is not a causative agent for endometrial cancer in Japanese women, and that a recent increase in the incidence of endometrial cancer in Japanese women may be related to changes in their life-style. However, although not statistically significant, women who used estrogen without progestin for 12 or more months had an OR of 2.552 (CI 0.231-28.192), while those who used estrogen with progestin for 12 or more months had an OR of 0.425 (CI 0.086-2.113). These results indicate that the addition of a progestin should be considered for reducing the risk of endometrial cancer in Japanese women.

Distribution of the muscarinic K+ channel proteins Kir3.1 and Kir3.4 in the ventricle, atrium, and sinoatrial node of heart

The functionally important effects on the heart of ACh released from vagal nerves are principally mediated by the muscarinic K+ channel. The aim of this study was to determine the abundance and cellular location of the muscarinic K+ channel subunits Kir3.1 and Kir3.4 in different regions of heart. Western blotting showed a very low abundance of Kir3.1 in rat ventricle, although Kir3.1 was undetectable in guinea pig and ferret ventricle. Although immunofluorescence on tissue sections showed no labeling of Kir3.1 in rat, guinea pig, and ferret ventricle and Kir3.4 in rat ventricle, immunofluorescence on single ventricular cells from rat showed labeling in t-tubules of both Kir3.1 and Kir3.4. Kir3.1 was abundant in the atrium of the three species, as shown by Western blotting and immunofluorescence, and Kir3.4 was abundant in the atrium of rat, as shown by immunofluorescence. Immunofluorescence showed Kir3.1 expression in SA node from the three species and Kir3.4 expression in the SA node from rat. The muscarinic K+ channel is activated by ACh via the m2 muscarinic receptor and, in atrium and SA node from ferret, Kir3.1 labeling was co-localized with m2 muscarinic receptor labeling throughout the outer cell membrane.

Heterogeneous expression of the delayed-rectifier K+ currents i(K,r) and i(K,s) in rabbit sinoatrial node cells

1. The electrical activity of sinoatrial node cells is heterogeneous. To understand the reasons for this, the density of the delayed-rectifier K+ current and its two components, i(K,r) and i(K,s), as a function of the size (as measured by cell capacitance) of rabbit sinoatrial node cells was investigated using the whole-cell voltage-clamp technique at 35 degrees C. 2. i(K,r) and i(K,s) were isolated using E-4031 and 293B. Features of the E-4031-sensitive and 293B-insensitive currents corresponded well to those of i(K,r), while features of the E-4031-insensitive and 293B-sensitive currents corresponded well to those of i(K,s). 3. The densities of the outward current under control conditions and the drug-sensitive and -insensitive currents were significantly (P < 0.01) correlated with cell capacitance, with current densities being greater in larger cells. 4. The effects of partial blockade of i(K,r) by 0.1 microM E-4031 on spontaneous action potentials were greater in smaller cells. 5. It is concluded that there are cell size-dependent differences in the density of the i(K,r) and i(K,s) components, and these may be involved in the heterogeneity of the electrical activity of single sinoatrial node cells as well as that of the intact sinoatrial node.

Immunohistochemical localization of aromatase and apoptosis-associated proteins in ovarian serous cystadenocarcinoma arising from ovarian endometriosis

An immunohistochemical study was made of a case of serous cystadenocarcinoma that had been shown to have arisen from ovarian endometriosis. Aromatase cytochrome P450 (P450arom), an enzyme responsible for estrogen biosynthesis, was localized in the epithelial linings of the endometriosis and faintly in the transitional part, whereas it was not expressed in the carcinoma tissue. In contrast, estrogen receptors, progesterone receptors, and apoptosis-associated proteins, Fas, Fas ligand, and Bax were expressed in both endometriosis and carcinoma tissues of the tumor, whereas Bcl-2 was not expressed in either tissue of the tumor. It was suggested that the undifferentiated shift of the histologic grade might result in the loss of P450arom and that the malignant transformation was not caused by an altered balance of apoptosis-associated proteins. Accumulation of these studies may lead to a better understanding of the nature of malignant transformation of ovarian endometriosis.

Identification of 16alpha,19-dihydroxyandrostenedione in the serum of pregnant women by gas chromatography-mass spectrometry

16alpha,19-Dihydroxyandrostenedione [16alpha,19-(OH)2 AD], a potential precursor of estriol, was identified in the serum of pregnant women by gas chromatography-mass spectrometry (GC-MS). Preliminary study indicated that the average serum concentration of 16alpha,19-(OH)2 AD in 10 normal pregnant women was 154.2+/-20 pg/ml. In contrast, the serum concentration of 16alpha,19-dihydroxydehydroepiandrosterone was less than the detection limit (30 pg/mI) of the GC-MS method.

Estrogen protects neuronal cells from amyloid beta-induced apoptotic cell death

Accumulating studies have shown that estrogen replacement therapy reduces the risk of Alzheimer's disease. In this study, we clarified that 17beta-estradiol (E2) significantly rescues PC12 neuronal cells from amyloid beta protein (Abeta)-induced cell death. We found that the amino acid residues of 25 to 35 (Abeta25-35) were more cytotoxic than the full length protein (Abeta1-40) and these residues induced DNA fragmentation typical for apopto- sis. In addition, E2 was confirmed to inhibit calcium influx and cytochrome c release induced by Abeta25-35. Since these sequential events cause apoptosis, the protective effect of E2 may be exerted not by the direct interaction with Abeta, but by the blockade of the mitochondrial apoptotic pathway induced by Abeta.

Two small intrahepatic cholangiocarcinomas with different sonographic appearances

We report on 2 cases of small intrahepatic (or peripheral) cholangiocarcinomas initially detected by sonography and completely resected. The lesions had a peripheral hypoechoic component and a central isoechoic or hyperechoic component. One had posterior acoustic shadowing on sonography, and the other did not. Comparison with pathologic findings in both cases indicated that severe fibrotic changes may have caused the posterior acoustic shadowing. This finding is extremely rare. We found only 1 previously reported case of cholangiocarcinoma accompanied by acoustic shadowing.

Possible involvement of Rho kinase in Ca2+ sensitization and mobilization by MCh in tracheal smooth muscle

We examined the effects of Rho kinase on contraction and intracellular Ca2+ concentration ([Ca2+](i)) in guinea pig trachealis by measuring isometric force and the fura 2 signal [340- to 380-nm fluorescence ratio (F340/F380)]. A Rho kinase inhibitor, Y-27632 (1-1,000 microM), inhibited methacholine (MCh)-induced contraction, with a reduction in F340/F380 in a concentration-dependent manner. The values of EC(50) for contraction and F340/F380 induced by 1 microM MCh with Y-27632 were 27.3 +/- 5.1 and 524.1 +/- 31.0 microM, respectively. With 0.1 microM MCh, the values for these parameters were decreased to 1.0 +/- 0.1 and 98.2 +/- 6.2 microM, respectively. Tension-F340/F380 curves for MCh indicated that Y-27632 caused an ~50% inhibition of MCh-induced contraction, without a reduction in F340/F380. These effects of Y-27632 were not inhibited by a protein kinase C inhibitor, GF-109203X. Our results indicate that inhibition of Rho kinase attenuates both Ca2+ sensitization and [Ca2+](i).

Progesterone inhibition of functional leptin receptor mRNA expression in human endometrium

Leptin is secreted by adipocytes and regulates appetite through interaction with hypothalamic leptin receptors (OB-R). Leptin is involved in the stimulation of reproductive functions, and local expression of leptin and OB-R in the ovary, oocyte, embryo, and placenta might play a role in early development. The mRNA and protein of the long form leptin receptor (OB-R(L)) but not of leptin are expressed in the human endometrium and the abundance of OB-R mRNA expression varies during the menstrual cycle with a peak in the early secretory phase. We examined the steroidal regulation of OB-R(L) mRNA expression. Northern blot analyses showed that in organ-cultured proliferative endometrial specimens, oestradiol (10(-9) and 10(-8) mol/l) had no acute effect on the OB-R(L) mRNA expression, whereas oestradiol plus progesterone (10(-8), 10(-7) and 10(-6) mol/l) or medroxyprogesterone acetate (10(-8) and 10(-7) mol/l) suppressed the expression by approximately 50%. This progestin-induced suppression was blocked by a concomitant addition of mifepristone. Additionally, incubation of endometrial specimens in the presence of leptin resulted in the phosphorylation of its intracellular target, STAT3 (signal transducer and activator of transcription 3). These results indicate that, in the human endometrium, progestins act via the progesterone receptors to suppress functional OB-R(L) mRNA expression, and may thereby alter the sensitivity of the endometrium to leptin.

Localization of interferon regulatory factor-1 in human endometrium throughout the menstrual cycle

OBJECTIVE

To determine the expression and localization of IRF-1 in human endometrium throughout the menstrual cycle.

DESIGN

A comparative study.

SETTING

Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine.

PATIENTS

Thirty-eight women aged 33 to 46 years, with regular menstrual cycles and nonpathological endometrium, undergoing hysterectomy.

INTERVENTION(S)

Endometrial tissues were obtained from operative samples.

MAIN OUTCOME MEASURE(S)

Expression of IRF-1 mRNA throughout the menstrual cycle was investigated using semiquantitative reverse transcription-polymerase chain reaction. Localization of IRF-1 protein was determined using immunohistochemistry.

RESULT(S)

IRF-1 mRNA was expressed in the human endometrium at each phase of the menstrual cycle. The immunoreactivity for IRF-1 was observed in the extranuclear compartment of the surface and glandular epithelial cells, both during the proliferative and secretory phases, as well as in the gland secretion during the secretory phase. In contrast, stromal cells were nearly unstained.

CONCLUSION(S)

IRF-1 was localized in the human endometrium, implying that this nuclear protein plays some role other than as a transcription factor.

Prognostic value of thymidine phosphorylase immunostaining in patients with uterine cervical cancer treated concurrently with doxifluridine, radiotherapy and immunotherapy

Thymidine phosphorylase (dThdPase) is reportedly identical to platelet-derived endothelial cell growth factor (PD-ECGF). We conducted immunohistochemical staining of dThdPase to assess correlation between its expression in cancer tissue and efficacy of a combination therapy with 5'-DFUR, radiotherapy and sizofilan (SPG) in uterine cervical cancer patients. No difference in response rates was observed between dThdPase positive and negative tumor and stromal cells. Survival curves significantly differed between stromal dThdPase positive and negative groups (p=0.032). Results showed that dThdPase immunostaining is possibly prognostic and predictive in determining success of the combination therapy.

Pacemaker shift in the rabbit sinoatrial node in response to vagal nerve stimulation

Effects of brief postganglionic vagal nerve stimulation on the activation sequence of the rabbit sinoatrial (SA) node were investigated. Activation sequences in a small area (7 mm x 7 mm) on the epicardial surface were measured in a beat-to-beat manner using an extracellular potential mapping system composed of 64 modified bipolar electrodes with high-gain and low-frequency band-pass filtering. The leading pacemaker site was recognised clearly from both the activation sequence and the characteristic morphology of the potentials. Vagal stimulation resulted in a short-lasting initial slowing of spontaneous rate followed by a long-lasting secondary slowing; a brief period of relative or absolute acceleration was interposed between the two slowing phases. During these changes of spontaneous rate, the leading pacemaker site shifted in a complex beat-to-beat manner by 1-6 mm alongside the crista terminalis in the superior or inferior direction. For the first spontaneous excitation following stimulation, the greater the slowing, the larger the distance of the pacemaker shift. There was no such linear relationship between the extent of slowing and the distance of pacemaker shift for the subsequent beats. These changes in the leading pacemaker site in response to vagal stimulation may be the result of the functional and morphological heterogeneity of the mammalian SA node in terms of innervation, receptor distribution and ion channel densities. Experimental Physiology (2001) 86.2, 177-184.

Effects of concomitant use of doxifluridine, radiotherapy and immunotherapy in patients with advanced cervical cancer

Clinical effects of doxifluridine (group A, 600 mg/body/day; group B, 800 mg/body/day) combined with radiotherapy and immunotherapy were evaluated in patients with advanced cancer of the uterine cervix. Response rates were 84.2% (16/19 patients) in group A and 100% (18/18 patients) in group B, respectively (p=0.230). There was no significant difference in adverse reaction incidence between the methods but significantly higher grade adverse reaction were observed in group B than in group A (p=0.048). Time to progression (TTP) was longer in group B than in group A (p=0.081). The optimal 5'-DFUR dose was 800 mg/body (group B), by which higher grade adverse reactions were fully controlled and TTP was prolonged.

Acupuncture on clinical symptoms and urodynamic measurements in spinal-cord-injured patients with detrusor hyperreflexia

OBJECTIVES

We investigated the possible use of acupuncture for the treatment of urinary incontinence caused by detrusor hyperreflexia in patients with chronic spinal cord injuries.

METHODS

A total of 13 patients (11 males, 2 females) suffering from urinary incontinence due to spinal cord injuries were treated by acupuncture, which was carried out with disposable stainless steel needles inserted into the bilateral BL-33 (Zhongliao) points on the skin of the third posterior sacral foramina. Urodynamic studies were also performed before acupuncture, immediately after the 1st acupuncture and 1 week after the 4th acupuncture. In 6 patients, these urodynamic studies were performed again 1 month after the 4th acupuncture.

RESULTS

No side effects were recognized throughout the treatment period. Of the 13 patients, incontinence disappeared in 2 (15%) and decreased to 50% or less compared to baseline in a further 6 (46%). Maximum cystometric bladder capacity increased significantly from 76.2 +/- 62.3 to 148.1 +/- 81.5 ml 1 week after the 4th acupuncture (p < 0.01). In the 6 patients in whom cystometry was repeated 1 month after the 4th acupuncture, bladder capacity decreased from 187.5 +/- 90.4 ml 1 week after the 4th acupuncture to 128.3 +/- 93.4 ml.

CONCLUSION

In spinal cord injury patients acupuncture could represent another valuable therapeutic alternative to the treatment of urinary incontinence caused by detrusor hyperreflexia.

Gonadal regulation of PrRP mRNA expression in the nucleus tractus solitarius and ventral and lateral reticular nuclei of the rat

We investigated the prolactin-releasing peptide (PrRP) gene expression quantitatively in the rat brain and the involvement of estrogen and progesterone using in situ hybridization. The strongest signals were observed in the nucleus tractus solitarius (NTS), which showed approximately 70% of total PrRP mRNA in the brain. Moderate expression was observed in the ventral and lateral reticular nuclei (VLRN) of the medulla oblongata. PrRP mRNA signals in the hypothalamic ventromedial- and dorsomedial nuclei showed only 5% of total signals. The PrRP mRNA expression among female rats showing normal gonadal cycle and male rats showed that the highest levels were in female rats in proestrus. Administration of estrogen or progesterone after ovariectomy induced an increase in PrRP mRNA expression in the NTS. PrRP mRNA content in the NTS increased with the progress of the pregnancy and reached a peak on the 14th day, the mid-period of pregnancy, when plasma progesterone increases. We also observed the colocalization of PrRP and estrogen receptor alpha in the neurons distributed in the NTS by double labeling immunocytochemistry. These findings indicate that PrRP gene expression is regulated by gonadal steroid hormones in the medulla oblongata, and parts of PrRP synthesizing neurons are considered to be directly influenced by estrogen in the NTS.

Gap junction remodeling in hypertrophied left ventricles of aortic-banded rats: prevention by angiotensin II type 1 receptor blockade

Remodeling of gap-junctional organization in hypertrophied left ventricle (LV) in response to pressure overload in rats induced by abdominal aorta banding was investigated by immunoconfocal and electron microscopy. Eight to 12 weeks after banding, rats developed significant LV hypertrophy. In contrast to control LV myocytes, which showed connexin43 (Cx43) labeling largely confined to the intercalated disks, LV myocytes from aortic-banded rats showed dispersion of punctate Cx43 labeling over the entire cell surface. In LV tissues sectioned longitudinally, the proportion of Cx43 label at the intercalated disk decreased significantly (control, 0.87 v aortic-banded, 0.62). En-face views of intercalated disks of hypertrophied myocardium revealed a reduction of Cx43 gap junctions in the disk center, giving rise to a significant decrease in the proportion of the disk occupied by gap-junctional membrane (control, 0.32 v aortic-banded, 0.24). Electron microscopy of hypertrophied LV tissue revealed that Cx43-containing gap junctions were frequently displaced from their usual locations to form side-to-side contacts distant from the disk, and also appeared as annular profiles. In aortic-banded rats treated with the angiotensin II (AII) type 1 receptor (AT1) antagonist, losartan (10 mg/kg/day, 11 weeks) not only LV hypertrophy, but also the gap junction disorganization was markedly reduced. These results suggest that LV hypertrophy induced by pressure overload is associated with Cx43 gap junction disorganization and that AII may play an important role either directly or indirectly in gap-junctional remodeling.