Prostaglandin D2 as a mediator of allergic asthma

Allergic asthma is caused by the aberrant expansion in the lung of T helper cells that produce type 2 (TH2) cytokines and is characterized by infiltration of eosinophils and bronchial hyperreactivity. This disease is often triggered by mast cells activated by immunoglobulin E (IgE)-mediated allergic challenge. Activated mast cells release various chemical mediators, including prostaglandin D2 (PGD2), whose role in allergic asthma has now been investigated by the generation of mice deficient in the PGD receptor (DP). Sensitization and aerosol challenge of the homozygous mutant (DP-/-) mice with ovalbumin (OVA) induced increases in the serum concentration of IgE similar to those in wild-type mice subjected to this model of asthma. However, the concentrations of TH2 cytokines and the extent of lymphocyte accumulation in the lung of OVA-challenged DP-/- mice were greatly reduced compared with those in wild-type animals. Moreover, DP-/- mice showed only marginal infiltration of eosinophils and failed to develop airway hyperreactivity. Thus, PGD2 functions as a mast cell-derived mediator to trigger asthmatic responses.

Altered pain perception and inflammatory response in mice lacking prostacyclin receptor

Prostanoids are a group of bioactive lipids working as local mediators and include D, E, F and I types of prostaglandins (PGs) and thromboxanes. Prostacyclin (PGI2) acts on platelets and blood vessels to inhibit platelet aggregation and to cause vasodilatation, and is thought to be important for vascular homeostasis. Aspirin-like drugs, including indomethacin, which inhibit prostanoid biosynthesis, suppress fever, inflammatory swelling and pain, and interfere with female reproduction, suggesting that prostanoids are involved in these processes, although it is not clear which prostanoid is the endogenous mediator of a particular process. Prostanoids act on seven-transmembrane-domain receptors which are selective for each type. Here we disrupt the gene for the prostacyclin receptor in mice by using homologous recombination. The receptor-deficient mice are viable, reproductive and normotensive. However, their susceptibility to thrombosis is increased, and their inflammatory and pain responses are reduced to the levels observed in indomethacin-treated wild-type mice. Our results establish that prostacyclin is an antithrombotic agent in vivo and provide evidence for its role as a mediator of inflammation and pain.

Impaired febrile response in mice lacking the prostaglandin E receptor subtype EP3

Fever, a hallmark of disease, is elicited by exogenous pyrogens, that is, cellular components, such as lipopolysaccharide (LPS), of infectious organisms, as well as by non-infectious inflammatory insults. Both stimulate the production of cytokines, such as interleukin (IL)-1beta, that act on the brain as endogenous pyrogens. Fever can be suppressed by aspirin-like anti-inflammatory drugs. As these drugs share the ability to inhibit prostaglandin biosynthesis, it is thought that a prostaglandin is important in fever generation. Prostaglandin E2 (PGE2) may be a neural mediator of fever, but this has been much debated. PGE2 acts by interacting with four subtypes of PGE receptor, the EP1, EP2, EP3 and EP4 receptors. Here we generate mice lacking each of these receptors by homologous recombination. Only mice lacking the EP3 receptor fail to show a febrile response to PGE2 and to either IL-1beta or LPS. Our results establish that PGE2 mediates fever generation in response to both exogenous and endogenous pyrogens by acting at the EP3 receptor.

Beneficial effects of antioxidants in diabetes: possible protection of pancreatic beta-cells against glucose toxicity

Oxidative stress is produced under diabetic conditions and possibly causes various forms of tissue damage in patients with diabetes. The aim of this study was to examine the involvement of oxidative stress in the progression of pancreatic beta-cell dysfunction in type 2 diabetes and to evaluate the potential usefulness of antioxidants in the treatment of type 2 diabetes. We used diabetic C57BL/KsJ-db/db mice, in whom antioxidant treatment (N-acetyl-L-cysteine [NAC], vitamins C plus E, or both) was started at 6 weeks of age; its effects were evaluated at 10 and 16 weeks of age. According to an intraperitoneal glucose tolerance test, the treatment with NAC retained glucose-stimulated insulin secretion and moderately decreased blood glucose levels. Vitamins C and E were not effective when used alone but slightly effective when used in combination with NAC. No effect on insulin secretion was observed when the same set of antioxidants was given to nondiabetic control mice. Histologic analyses of the pancreases revealed that the beta-cell mass was significantly larger in the diabetic mice treated with the antioxidants than in the untreated mice. As a possible cause, the antioxidant treatment suppressed apoptosis in beta-cells without changing the rate of beta-cell proliferation, supporting the hypothesis that in chronic hyperglycemia, apoptosis induced by oxidative stress causes reduction of beta-cell mass. The antioxidant treatment also preserved the amounts of insulin content and insulin mRNA, making the extent of insulin degranulation less evident. Furthermore, expression of pancreatic and duodenal homeobox factor-1 (PDX-1), a beta-cell-specific transcription factor, was more clearly visible in the nuclei of islet cells after the antioxidant treatment. In conclusion, our observations indicate that antioxidant treatment can exert beneficial effects in diabetes, with preservation of in vivo beta-cell function. This finding suggests a potential usefulness of antioxidants for treating diabetes and provides further support for the implication of oxidative stress in beta-cell dysfunction in diabetes.

Abortive expansion of the cumulus and impaired fertility in mice lacking the prostaglandin E receptor subtype EP(2)

Female mice lacking the gene encoding the prostaglandin (PG) E(2) receptor subtype EP(2) (EP(2)(-/-)) become pregnant and deliver their pups at term, but with a much reduced litter size. A decrease in ovulation number and a much reduced fertilization rate were observed in EP(2)(-/-) females without difference of the uterus to support implantation of wild-type embryos. Treatment with gonadotropins induced EP(2) mRNA expression in the cumulus cells of ovarian follicles of wild-type mice. The immature cumuli oophori from wild-type mice expanded in vitro in response to both follicle-stimulating hormone and PGE(2), but the response to PGE(2) was absent in those from EP(2)(-/-) mice. Cumulus expansion proceeded normally in preovulatory follicles but became abortive in a number of ovulated complexes in EP(2)(-/-) mice, indicating that EP(2) is involved in cumulus expansion in the oviduct in vivo. No difference in the fertilization rate between wild-type and EP(2)(-/-) mice was found in in vitro studies using cumulus-free oocytes. These results indicate that PGE(2) cooperates with gonadotropin to complete cumulus expansion for successful fertilization.

Role of citron kinase as a target of the small GTPase Rho in cytokinesis

During mitosis, a ring containing actin and myosin appears beneath the equatorial surface of animal cells. This ring then contracts, forms a cleavage furrow and divides the cell, a step known as cytokinesis. The two daughter cells often remain connected by an intercellular bridge which contains a refringent structure known as the midbody. How the appearance of this ring is regulated is unclear, although the small GTPase Rho, which controls the formation of actin structures, is known to be essential. Protein kinases are also thought to participate in cytokinesis. We now show that a splice variant of a Rho target protein, named citron, contains a protein kinase domain that is related to the Rho-associated kinases ROCK14 and ROK, which regulate myosin-based contractility. Citron kinase localizes to the cleavage furrow and midbody of HeLa cells; Rho is also localized in the midbody. We find that overexpression of citron mutants results in the production of multinucleate cells and that a kinase-active mutant causes abnormal contraction during cytokinesis. We propose that citron kinase regulates cytokinesis at a step after Rho in the contractile process.

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS): a correlative study of the clinical features and mitochondrial DNA mutation

We studied 40 MELAS patients (21 male and 19 female) to characterize the clinical features and biochemical and muscle biopsy findings related to the mtDNA mutation at the nucleotide position of 3,243, the most common genetic defect in MELAS. The most frequent symptom was episodic sudden headache with vomiting and convulsions, which commonly affected patients aged 5 to 15 years (80%). Biochemical defects in the muscle were variable; 13 patients had complex I, seven complex IV, and four complexes I + IV deficiencies. In four muscle biopsies without ragged-red fibers or any enzyme defect, we based the diagnosis on the identification of strongly SDH-reactive blood vessels, which occurred in 87.5% of the biopsies. The mtDNA mutation was present in 32 of 40 patients (80%). We conclude that there are no clinical and pathologic differences between the patients with and without this mtDNA mutation.

Patent ductus arteriosus and neonatal death in prostaglandin receptor EP4-deficient mice

The physiological role of the prostaglandin E2 receptor EP4 subtype was investigated by generation of EP4-deficient-mice by gene targeting. Loss of the EP4 receptor was not lethal in utero, but most EP4 (-/-) neonates became pale and lethargic approximately 24 h after birth and died within 72 h. Less than 5% of the EP4 (-/-) mice survived and grew normally more than a year. Histological examination revealed that the ductus arteriosus in dead neonates remained open, while it was partially closed in the survivors. In situ hybridization study showed that EP4 mRNA was strongly expressed in the ductus. These results suggest that neonatal death is at least partly due to patent ductus arteriosus and that the EP4 receptor plays a role in regulation of the patency of this vessel. They also indicate that normal function of the EP4 receptor is essential in neonatal adaptation of the circulatory system.

Subtotal corpectomy versus laminoplasty for multilevel cervical spondylotic myelopathy: a long-term follow-up study over 10 years

STUDY DESIGN

A retrospective study was conducted.

OBJECTIVE

To compare the long-term outcomes of subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

No study has compared the long-term outcomes between subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

METHODS

In this study, 23 patients treated with subtotal corpectomy and 24 patients treated with laminoplasty were followed up for 10 to 14 years after surgery. Neurologic recovery, late deterioration, axial pain, radiographic results (degenerative changes at adjacent levels, alignment, and range of motion of the cervical spine), and surgical complications were compared between the two groups.

RESULTS

No significant difference in neurologic recovery was found between the two groups 1 and 5 years after surgery, or at the latest follow-up assessment. Neurologic status deteriorated in one patient of the subtotal corpectomy group because of adjacent degeneration, and in one patient of the laminoplasty group because of hyperextension injury. Axial pain was observed in 15% of the corpectomy group and in 40% of the laminoplasty group (P < 0.05). In the corpectomy group, listhesis exceeding 2 mm developed at 38% of the upper adjacent levels, and osteophyte formation at 54% of the lower adjacent levels. In the laminoplasty group, kyphotic deformity developed in one patient (6%) after surgery. In the corpectomy group, the mean vertebral range of motion had decreased from 39.4 degrees to 19.2 degrees (49%) by the final follow-up assessment. In the laminoplasty group, the mean vertebral range of motion had decreased from 40.2 degrees to 11.6 degrees (29%) by the final follow-up assessment. Neurologic complications related to the surgery occurred in two patients (one myelopathy from bone graft dislodgement and one C5 root palsy from bone graft fracture) of the corpectomy group and four patients (C5 root palsy) of the laminoplasty group. All of these patients recovered over time. The corpectomy group needed longer operative time (P < 0.001) and tended to have more blood loss (P = 0.24). Six patients in the corpectomy group needed posterior interspinous wiring because of pseudarthrosis.

CONCLUSIONS

Subtotal corpectomy and laminoplasty showed an identical effect from a surgical treatment for multilevel cervical spondylotic myelopathy. These neurologic recoveries usually last more than 10 years. In the subtotal corpectomy group, the disadvantages were longer surgical time, more blood loss, and pseudarthrosis. In the laminoplasty group, axial pain occurred frequently, and the range of motion was reduced severely.

Glycation-dependent, reactive oxygen species-mediated suppression of the insulin gene promoter activity in HIT cells

Prolonged poor glycemic control in non-insulin-dependent diabetes mellitus patients often leads to a decline in insulin secretion from pancreatic beta cells, accompanied by a decrease in the insulin content of the cells. As a step toward elucidating the pathophysiological background of the so-called glucose toxicity to pancreatic beta cells, we induced glycation in HIT-T15 cells using a sugar with strong deoxidizing activity, D-ribose, and examined the effects on insulin gene transcription. The results of reporter gene analyses revealed that the insulin gene promoter is more sensitive to glycation than the control beta-actin gene promoter; approximately 50 and 80% of the insulin gene promoter activity was lost when the cells were kept for 3 d in the presence of 40 and 60 mM D-ribose, respectively. In agreement with this, decrease in the insulin mRNA and insulin content was observed in the glycation-induced cells. Also, gel mobility shift analyses using specific antiserum revealed decrease in the DNA-binding activity of an insulin gene transcription factor, PDX-1/IPF1/STF-1. These effects of D-ribose seemed almost irreversible but could be prevented by addition of 1 mM aminoguanidine or 10 mM N-acetylcysteine, thus suggesting that glycation and reactive oxygen species, generated through the glycation reaction, serve as mediators of the phenomena. These observations suggest that protein glycation in pancreatic beta cells, which occurs in vivo under chronic hyperglycemia, suppresses insulin gene transcription and thus can explain part of the beta cell glucose toxicity.

A detailed linkage map of medaka, Oryzias latipes: comparative genomics and genome evolution

We mapped 633 markers (488 AFLPs, 28 RAPDs, 34 IRSs, 75 ESTs, 4 STSs, and 4 phenotypic markers) for the Medaka Oryzias latipes, a teleost fish of the order Beloniformes. Linkage was determined using a reference typing DNA panel from 39 cell lines derived from backcross progeny. This panel provided unlimited DNA for the accumulation of mapping data. The total map length of Medaka was 1354.5 cM and 24 linkage groups were detected, corresponding to the haploid chromosome number of the organism. Thirteen to 49 markers for each linkage group were obtained. Conserved synteny between Medaka and zebrafish was observed for 2 independent linkage groups. Unlike zebrafish, however, the Medaka linkage map showed obvious restriction of recombination on the linkage group containing the male-determining region (Y) locus compared to the autosomal chromosomes.

Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells

Nitric oxide (NO) is believed to be an effector molecule that mediates interleukin (IL)-1 beta-induced destruction and dysfunction of pancreatic beta-cells. We have demonstrated that both exogenous NO and NO generated endogenously by IL-1 beta brought about apoptosis of isolated rat pancreatic islet cells as well as pancreatic beta-cell tumor-derived cell line HIT. This apoptosis was characterized by cleavage of DNA into nucleosomal fragments of 180-200 bp and morphologically by nuclear shrinkage, chromatic condensation, and apoptotic body formation. The IL-1 beta-induced internucleosomal DNA cleavage occurred in a time- and dose-dependent manner. Actinomycin D, cycloheximide, and nitric oxide synthase inhibitors inhibited the DNA cleavage, which was correlated with the amount of NO produced, indicating that NO produced by HIT cells themselves could mediate the apoptosis. Furthermore, in the presence of tumor necrosis factor (TNF)-alpha, large amounts of NO were produced by IL-1 beta and DNA cleavage occurred more noticeably, although TNF-alpha alone did not generate NO. Streptozotocin (STZ), a diabetogenic reagent containing a nitroso moiety, also released NO and induced internucleosomal DNA cleavage in HIT cells. These results suggest that NO-induced internucleosomal DNA cleavage is an important initial step in the destruction and dysfunction of pancreatic beta-cells induced by inflammatory stimulation or treatment with STZ.

Systematic lymph node dissection for clinically diagnosed peripheral non-small-cell lung cancer less than 2 cm in diameter

The value of radical systematic lymphadenectomy for treatment of early-stage bronchial carcinoma is controversial. We performed a prospective randomized study to address this question. Altogether 115 patients with peripheral non-small-cell lung cancers smaller than 2 cm in diameter were enrolled in this study. They were randomly assigned into a lobectomy with lymph node sampling group (sampling group, n = 56) or a lobectomy with radical systematic lymph node dissection group (dissection group, n = 59). Inclusion criteria were based only on preoperative clinical studies. Four tumors were larger than 2 cm postoperatively. One patient had disseminated disease, and two had intrapulmonary metastases discovered at surgery. Two patients had small-cell carcinoma. There were four with pathologic N1 disease and seven with N2 disease in the dissection group and three with N1 and eight with N2 disease in the sampling group. The numbers of local and distant recurrences were two and six, respectively, in the dissection group and two and five in the sampling group. The overall 5-year survival was 81% in the dissection group and 84% in the sampling group. No significant differences in the recurrence rate or survival was seen between the groups. Our results demonstrate that clinically evaluated peripheral non-small-cell carcinomas smaller than 2 cm in diameter do not require radical systematic mediastinal and hilar lymph node dissection.

Plasma devices to guide and collimate a high density of MeV electrons

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

Strongly succinate dehydrogenase-reactive blood vessels in muscles from patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes

Intramuscular blood vessels were examined with succinate dehydrogenase stain in skeletal muscle biopsy specimens from 6 patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Almost all arteries had large granular deposits with high succinate dehydrogenase activity in their walls. Electron microscopic examination of serial frozen sections of these biopsies showed that the smooth muscle cells of the strongly succinate dehydrogenase-reactive blood vessels contained markedly proliferated mitochondria, characteristic of patients with MELAS. The presence of strongly succinate dehydrogenase-reactive blood vessels in muscle biopsy specimens provides an important clue toward understanding the underlying pathogenetic mechanism in patients with MELAS as well as another approach to the diagnosis of this disorder.

Inhibition of extracellular signal-regulated protein kinase or c-Jun N-terminal protein kinase cascade, differentially activated by cisplatin, sensitizes human ovarian cancer cell line

We have studied the roles of c-Jun N-terminal protein kinase (JNK) and extracellular signal-regulated protein kinase (ERK) cascade in both the cisplatin-resistant Caov-3 and the cisplatin-sensitive A2780 human ovarian cancer cell lines. Treatment of both cells with cisplatin but not transplatin isomer activates JNK and ERK. Activation of JNK by cisplatin occurred at 30 min, reached a plateau at 3 h, and declined thereafter, whereas activation of ERK by cisplatin showed a biphasic pattern, indicating the different time frame. Activation of JNK by cisplatin was maximal at 1000 microM, whereas activation of ERK was maximal at 100 microM and was less at higher concentrations, indicating the different dose dependence. Cisplatin-induced JNK activation was neither extracellular and intracellular Ca(2+)- nor protein kinase C-dependent, whereas cisplatin-induced ERK activation was extracellular and intracellular Ca(2+)- dependent and protein kinase C-dependent. A mitogen-activated protein kinase/extracellular signal-regulated kinase kinase inhibitor, PD98059, had no effect on the cisplatin-induced JNK activity, suggesting an absence of cross-talk between the ERK and JNK cascades. We further examined the effect of each cascade on the viability following cisplatin treatment. Either exogenous expression of dominant negative c-Jun or the treatment by PD98059 induced sensitivity to cisplatin in both cells. Our findings suggest that cisplatin-induced DNA damage differentially activates JNK and ERK cascades and that inhibition of either of these cascades sensitizes ovarian cancer cells to cisplatin.

The human glucokinase gene beta-cell-type promoter: an essential role of insulin promoter factor 1/PDX-1 in its activation in HIT-T15 cells

The glycolytic enzyme glucokinase plays a primary role in the glucose-responsive secretion of insulin, and defects of this enzyme can cause NIDDM. As a step toward understanding the molecular basis of glucokinase (GK) gene regulation, we assessed the structure and regulation of the human GK gene beta-cell-type promoter. The results of reporter gene analyses using HIT-T15 cells revealed that the gene promoter was comprised of multiple cis-acting elements, including two primarily important cis-motifs: a palindrome structure, hPal-1, and the insulin gene cis-motif A element-like hUPE3. While both elements were bound specifically by nuclear proteins, it was the homeodomain-containing transcription factor insulin promoter factor 1 (IPF1)/STF-1/PDX-1 that bound to the hUPE3 site: IPF1, when expressed in CHO-K1 cells, became bound to the hUPE3 site and activated transcription. An anti-IPF1 antiserum used in gel-mobility shift analysis supershifted the DNA protein complex formed with the hUPE3 probe and nuclear extracts from HIT-T15 cells, thus supporting the involvement of IPF1 in GK gene activation in HIT-T15 cells. In contrast to the insulin gene, however, neither the synergistic effect of the Pan1 expression on the IPF1-induced promoter activation nor the glucose responsiveness of the activity was observed for the GK gene promoter. These results revealed some conservative but unique features for the transcriptional regulation of the beta-cell-specific genes in humans. Being implicated in insulin and GK gene regulations as a common transcription factor, IPF1/STF-1/PDX-1 is likely to play an essential role in maintaining normal beta-cell functions.

PGE(2) -EP(2) signalling in endothelium is activated by haemodynamic stress and induces cerebral aneurysm through an amplifying loop via NF-κB

BACKGROUND AND PURPOSE

Cerebral aneurysm is a frequent cerebrovascular event and a major cause of fatal subarachnoid haemorrhage, but there is no medical treatment for this condition. Haemodynamic stress and, recently, chronic inflammation have been proposed as major causes of cerebral aneurysm. Nevertheless, links between haemodynamic stress and chronic inflammation remain ill-defined, and to clarify such links, we evaluated the effects of prostaglandin E(2) (PGE(2) ), a mediator of inflammation, on the formation of cerebral aneurysms.

EXPERIMENTAL APPROACH

Expression of COX and prostaglandin E synthase (PGES) and PGE receptors were examined in human and rodent cerebral aneurysm. The incidence, size and inflammation of cerebral aneurysms were evaluated in rats treated with COX-2 inhibitors and mice lacking each prostaglandin receptor. Effects of shear stress and PGE receptor signalling on expression of pro-inflammatory molecules were studied in primary cultures of human endothelial cells (ECs).

KEY RESULTS

COX-2, microsomal PGES-1 and prostaglandin E receptor 2 (EP(2) ) were induced in ECs in the walls of cerebral aneurysms. Shear stress applied to primary ECs induced COX-2 and EP(2) . Inhibition or loss of COX-2 or EP(2) in vivo attenuated each other's expression, suppressed nuclear factor κB (NF-κB)-mediated chronic inflammation and reduced incidence of cerebral aneurysm. EP(2) stimulation in primary ECs induced NF-κB activation and expression of the chemokine (C-C motif) ligand 2, essential for cerebral aneurysm.

CONCLUSIONS AND IMPLICATIONS

These results suggest that shear stress activated PGE(2) -EP(2) pathway in ECs and amplified chronic inflammation via NF-κB. We propose EP(2) as a therapeutic target in cerebral aneurysm.

Analysis of 372 patients with Crush syndrome caused by the Hanshin-Awaji earthquake

OBJECTIVE

To clarify clinical features and determine the severity of injuries in patients with crush syndrome in Hanshin-Awaji earthquake.

METHODS

We retrospectively reviewed medical records of 6,107 patients hospitalized in 95 hospitals, and identified 372 patients with crush syndrome.

RESULTS

The major sites of crush injury were in the lower extremities (74%), followed by the upper extremities (10%), and the trunk (9%). Pelvic fractures, limb fractures, and abdominal injuries were the most frequently associated injury. Patients with trunk compression and/or with abdominal injury had a higher mortality rate. A total of 50 patients (13.4%) died. The causes of death within 5 days after the earthquake were hypovolemia and hyperkalemia. Peak serum creatine kinase concentration increased with the number of crushed extremities. Mortality and the risk of acute renal failure were higher in patients with creatine kinase concentration more than 75,000 micro/L.

CONCLUSIONS

Peak serum concentration of creatine kinase as well as the number of injured extremities serve to estimate the severity of crush syndrome.

PDX-1 induces insulin and glucokinase gene expressions in alphaTC1 clone 6 cells in the presence of betacellulin

The pancreatic beta- and alpha-cells are developmentally related to each other but reveal diverse gene expression patterns. Among the two important transcription factors for insulin gene expression, IEF1 is present both in alpha- and beta-cells, but PDX-1/IPF1/STF-1/IDX-1, a homeodomain-containing transcription factor, is present in beta-cells but not in alpha-cells. To elucidate the function of PDX-1 in the expression of beta-cell-specific genes, we established stable alphaTC1 clone 6 (alphaTC1.6)-derived transfectants expressing PDX-1 and examined the changes in the gene expression patterns in them. The exogenous expression of PDX-1 in alphaTC1.6 cells alone could induce islet amyloid polypeptide (IAPP) mRNA expression in the cells but not the expression of insulin, glucokinase, or GLUT2 gene. However, when betacellulin was added to the medium, the PDX-1-expressing alphaTC1.6 cells, but not the control alphaTC1.6 cells, came to express insulin and glucokinase mRNAs. This did not occur with other growth factors such as epidermal growth factor, transforming growth factor alpha, and insulin-like growth factor I. GLUT2 mRNA remained undetectable in the PDX-1--expressing alphaTC1.6 cells. These observations demonstrate the potency of PDX-1 for the expression of the insulin, glucokinase, and IAPP genes and suggest that certain regulatory factors, which can partially be modified by betacellulin, also contribute to the beta-cell specificity of gene expression.

Temporal changes and geographical differences in multiple sclerosis phenotypes in Japanese: nationwide survey results over 30 years

Background

There are two distinct phenotypes of multiple sclerosis (MS) in Asians, manifesting as optic-spinal (OSMS) and conventional (CMS) forms. In Japan, four nationwide surveys of MS have been conducted. The first three were in 1972, 1982, and 1989, and we performed the fourth in 2004.

Results

The recent survey showed six main findings as follows: (1) a four-fold increase in the estimated number of clinically definite patients with MS in 2003 (9900; crude MS prevalence, 7.7/100,000) compared with 1972; (2) a shift in the peak age at onset from early 30s in 1989 to early 20s in 2003; (3) a successive proportional decrease in optic-spinal involvement in clinically definite patients with MS; (4) a significant north–south gradient for the CMS/OSMS ratio; (5) after subdivision of the mainland (30–45° North) into northern and southern parts at 37°N, northern-born northern residents (northern patients) showed a significantly higher CMS/OSMS ratio and higher frequency of brain lesions fulfilling the Barkhof criteria (Barkhof brain lesions) than southern-born southern residents (southern patients); (6) among northern patients, the absolute numbers of patients with CMS and those with Barkhof brain lesions rapidly increased with advancing birth year.

Conclusions

These findings suggest that MS phenotypes are drastically altered by environmental factors, such as latitude and “Westernization.”

Depression of membrane-bound Na+-K+-ATPase activity induced by free radicals and by ischemia of kidney

A partially purified, membrane-bound Na+-K+-ATPase fraction, prepared from the outer medulla of porcine kidney, was incubated in the presence of 0.1 mM FeCl3, 1 mM ADP, and 0.1-100 mM H2O2 for either 15 or 30 min at 37 degrees C. The activity of ouabain-sensitive Na+-K+-ATPase was reduced proportionally to the concentration of H2O2 and the duration of incubation. There were decreases in SH contents and turnover rates of the Na+-K+-ATPase preparation, while malondialdehyde (MDA) and conjugated dienes were generated from the membrane lipids in the course of the incubation. The concentrations of ethanolamine (E) plasmalogen and of arachidonic acid in the E glycerophospholipid molecules were reduced by the free radical reaction. Similarly, a reduction in Na+-K+-ATPase activity and the formation of MDA and conjugated dienes, together with a decrease in E glycerophospholipids, were observed when the membrane fraction was exposed to ultraviolet irradiation (254 nm) for 30 min at 4 degrees C. Administration of 10 mM dithiothreitol alleviated the reductions in enzyme activity, in turnover rate, and in SH content without suppressing MDA formation. Addition of 2 mM butylated hydroxytoluene to the incubation mixture prevented the lipid peroxidation without totally normalizing the enzyme activity in the H2O2 experiment, whereas this antioxidant restored the ATPase activity to normal in the ultraviolet experiment. Microsomal fractions, prepared from the outer medulla of canine kidney after 1 h of unilateral ischemia and 1 h of reperfusion, showed a decreased Na+-K+-ATPase activity, a reduced amount of SH groups, and an increased MDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional coupling of human right and left cortical motor areas demonstrated with partial coherence analysis

Although a linear correlation between oscillatory activities in the right and left motor cortices during movements has been shown in monkeys, there has been a debate whether scalp-recorded EEG coherence in human reflects a similar association. By applying partial coherence analysis, we demonstrated that interhemispheric coherence during movements cannot be explained by contamination from the occipital alpha rhythm or common reference signal. A significant increase of net interhemispheric communication in the beta1 band was shown during movements. We propose that the partial coherence method can be a useful tool to measure cortico-cortical functional coupling reliably.

Retinal nerve fiber layer defect as an early manifestation of diabetic retinopathy

PURPOSE

An incidence of and risk factors for retinal nerve fiber layer defect were investigated in patients with type II diabetes mellitus and compared with that of age-matched control subjects.

METHODS

The authors photographed the retinal nerve fiber layer of the right eye in each of 137 patients with diabetes and 144 healthy control subjects. The level of diabetic retinopathy ranged from levels 1 (no microaneurysm) to 4 (eyes with localized intra-retinal microvascular abnormalities or venous beading). Risk factors for the nerve fiber layer defect analyzed were age of patients, visual acuity, axial length, optic disc size, glycosylated hemoglobin, systolic blood pressure, and level of diabetic retinopathy.

RESULTS

Defects of the retinal nerve fiber layer were found in 6/30 (20%) eyes with level 1 retinopathy, 8/14 (57%) eyes with level 2 retinopathy, 24/47 (51%) eyes with level 3 retinopathy, and 36/46 (78%) eyes with level 4 retinopathy. These defect incidences were significantly higher than that of the control group, which had 5/144 (3.5%) defects (P < or = 0.001). Risk factors for this nerve defect were level of diabetic retinopathy (P = 0.002), high systolic blood pressure (P = 0.0232), and patient's age (P = 0.0478). Not correlated with the incidence of the retinal nerve fiber layer defect were visual acuity, disc size, axial length, and glycosylated hemoglobin level at the time of examination.

CONCLUSION

These findings suggest that the retinal nerve fiber layer defect is common in patients with early diabetic retinopathy. Risk factors for this defect were higher level of diabetic retinopathy, systemic hypertension, and advanced age.