Expression and genetic interaction of transcription factors GATA-2 and GATA-3 during development of the mouse central nervous system

Here we examine the expression of transcription factors GATA-2 and GATA-3 during early stages of embryonic development in the central nervous system (CNS) of the mouse. GATA-2 is expressed as early as 9 dpc in the hindbrain, in ventral rhombomere 4, and transiently in ventral rhombomere 2 (r2). From 9.5 to 11.5 dpc, activation of the gene spreads to many sites of early neuronal differentiation, such as the olfactory bulbs, the pretectum, and the oculomotor nucleus in the midbrain, a thin stripe of cells lining the floor plate from the mesencephalon to the cervical spinal cord and a ventral column of cells spanning the neural tube from rostral hindbrain and including motor neuron as well as ventral interneuron precursors. GATA-3 is expressed in a pattern very similar to that of GATA-2. Distinguishing features are the lack of expression in r2 at 9 dpc and a slight delay in its activation. In addition, GATA-2 is activated in both the ventricular and the subventricular zones of the neural tube, whereas GATA-3 is restricted mainly to the subventricular zone. Expression analyses performed on GATA-2 -/- mouse embryos between E9.5 and 10.5 dpc established that: (i) the expression of GATA-3 in the developing CNS of the mouse embryo is dependent on the presence of GATA-2 and (ii) loss of GATA-2 leads to severe defects in neurogenesis, which strongly suggests that GATA-2 is involved, as in hematopoiesis, in the maintenance of the pool of ventral neuronal progenitors.

Different sequence requirements for expression in erythroid and megakaryocytic cells within a regulatory element upstream of the GATA-1 gene

The lineage-restricted transcription factor GATA-1 is required for differentiation of erythroid and megakaryocytic cells. We have localized a 317 base pair cis-acting regulatory element, HS I, associated with a hematopoietic-specific DNase I hypersensitive site, which lies approx. 3.7 kilobases upstream of the murine hematopoietic-specific GATA-1 IE promoter. HS I directs high-level expression of reporter GATA-1/lacZ genes to primitive and definitive erythroid cells and megakaryocytes in transgenic mice. Comparative sequence analysis of HS I between human and mouse shows approx. 63% nucleotide identity with a more conserved core of 169 base pairs (86% identity). This core contains a GATA site separated by 10 base pairs from an E-box motif. The composite motif binds a multi-protein hematopoietic-specific transcription factor complex which includes GATA-1, SCL/tal-1, E2A, Lmo2 and Ldb-1. Point mutations of the GATA site abolishes HS I function, whereas mutation of the E-box motif still allows reporter gene expression in both lineages. Strict dependence of HS I activity on a GATA site implies that assembly of a protein complex containing a GATA-factor, presumably GATA-1 or GATA-2, is critical to activating or maintaining its function. Further dissection of the 317 base pair region demonstrates that, whereas all 317 base pairs are required for expression in megakaryocytes, only the 5′ 62 base pairs are needed for erythroid-specific reporter expression. These findings demonstrate differential lineage requirements for expression within the HS I element.

Benzimidazolium triflate-activated synthesis of (6-4) photoproduct-containing oligonucleotides and its application

In the solid-phase synthesis of oligonucleotides containing the pyrimidine(6-4)pyrimidone photoproduct using a dinucleotide building block, considerable amounts of by-products were found as the chain length increased. The by-products were the major product when a 49mer was synthesized on a 40 nmol scale. It was assumed that these by-products were formed by the coupling of phosphoramidites with the N3 imino function of the 5' component of the (6-4) photoproduct. We examined imidazolium triflate and benzimidazolium triflate to find an alternative activator for DNA synthesis. Imidazolium triflate prevented by-product formation to some extent, but the coupling yields were low. Benzimidazolium triflate was comparable to tetrazole in coupling efficiency and reduced by-product formation to a great extent, without modification of the synthesizer program. The obtained 49mer was used to detect proteins that recognize UV-damaged DNA in HeLa cell extracts. Two major protein-DNA complexes were found when a 49mer duplex was used as probe, while a 30mer duplex failed to detect one of them. This application showed the usefulness of long chain 'damaged' oligonucleotides in biochemical studies.

Complete regression of recurrent esophageal carcinoma with reduced expression of glutathione S-transferase-pi by treatment with continuous infusion of 5-fluorouracil and low-dose cisplatin infusion

The mortality rate of recurrent esophageal carcinoma remains high because of its resistance to chemotherapy and radiation therapy. We present a patient with recurrent esophageal carcinoma, which dramatically disappeared after treatment with the combination of continuous infusion of 5-fluorouracil and low-dose cis-Diamminedichloroplatinum-II (cisplatin) infusion (FP therapy). Furthermore, we immunohistologically found that glutathione S-transferases (GST)-pi, a marker of resistance to cisplatin, was faintly expressed both in the endoscopical biopsy specimens of recurrent tumor and in the resected specimens of esophageal carcinoma and metastatic lymph nodes. FP therapy was suggested to be effective for recurrent esophageal carcinoma. Immunostaining for GST-pi might be a prospective marker for the sensitivity of esophageal carcinoma to FP therapy, particularly cisplatin.

Treatment of sudden sensorineural hearing loss with a continuous epidural block

The efficacy of a continuous epidural block was evaluated in the treatment of 20 patients with sudden sensorineural hearing loss (SNHL). Ten patients were treated with continuous cervicothoracic epidural block (group A) and the other 10 were treated with stellate ganglion block (group B). No significant difference in factors affecting prognosis was noted between the groups. In the epidural block group 70% achieved substantial hearing improvement, while this occurred in only 30% of patients undergoing stellate ganglion block. These findings suggest that continuous epidural block can be effective in the treatment of sudden SNHL.

The position and size of radiological nephrogram in Japanese preschool children

The early detection of retroperitoneal masses in children, such as neuroblastoma, Wilm's tumor, hydronephrosis and cystic renal diseases, has a great clinical importance for the improvement of their prognosis. The kidney is often affected in its size or position by these lesions, and occasionally allows clinicians to find a clue to reach the correct diagnosis before the patient become symptomatic. Since we had no clinically available nomogram on the position and the size of the kidney in Japanese children, we measured the size and position of the kidneys on plain abdominal x-rays in 347 Japanese children in preschool years with a special attention to their relationship with the spine. As a result, the nomogram showed age dependent growth of the kidneys keeping almost the same ratio with the spine, while the distance between the upper pole of the kidney and the spine remained less than 10 mm in all age groups. Our nomogram may be useful not only for picking up the malposition of the kidneys but also for the follow up of the patients with chronic renal diseases affecting the growth of the kidneys.

[A case of right ventricular rupture due to blunt trauma]

A 33-year-old male was involved in a single motor vehicle accident and was referred to our hospital 135 minutes after injury. He had a sign of cardiac tamponade and immediately pericardial window was performed at the emergency department, but hypotension went worse. We transferred him to the operating room, and a median sternotomy could be done after cardiopulmonary resuscitation. There was a 4 cm tear in the right ventricular outlet and that was repaired primarily. Cardiac rupture due to blunt trauma is highly lethal, and prompt diagnosis is necessary for a favorable outcome. A high index of suspicion, avoidance of unnecessary diagnostic studies, and immediate surgical intervention are critical for successful management.

Improved reporter strain for monitoring Cre recombinase-mediated DNA excisions in mice

Effective use of conditional Cre recombinase-loxP gene modification requires Cre-expressing mouse strains with defined patterns of expression. To assess the in vivo functionality of Cre-expressing mice, we have engineered an improved reporter strain for monitoring Cre-mediated excisions. The beta-galactosidase-neomycin phosphotransferase fusion gene (betageo)-trapped ROSA26 locus was modified by gene targeting such that betageo is expressed only after Cre-mediated excision of loxP-flanked DNA sequences. betageo from the excised ROSA26 allele is expressed ubiquitously in embryos and adult mice. By mating the reporter strain with Cre-expressing transgenic mice, we have shown that the loxP-flanked ROSA26 allele is accessible to Cre during early embryogenesis, as well as in a specific hematopoietic lineage (T lymphocytes). This improved reporter strain should facilitate monitoring in vivo Cre-mediated excision events in a variety of experimental contexts.

Possible mechanism for lead inhibition of vascular endothelial cell proliferation: a lower response to basic fibroblast growth factor through inhibition of heparan sulfate synthesis

Although lead inhibits the proliferation of vascular endothelial cells, the mechanism has been incompletely understood. A lower response to basic fibroblast growth factor (bFGF) of growing bovine aortic endothelial cells after exposure to lead was investigated using a cell culture system in the present study. It was shown that lead significantly decreased the incorporation of [3H]thymidine into the acid-insoluble fraction of the cells but the inhibition disappeared in the presence of bFGF neutralizing antibody. Pretreatment with lead resulted in a reduction of the stimulation by exogenous bFGF on the [3H]thymidine incorporation. Lead decreased endogenous bFGF bound to cell surface heparan sulfate proteoglycans in a concentration-dependent manner but not the high affinity FGF receptor without a change of the accumulation within the cells. In spite of such a change in the endogenous bFGF distribution, the total amount of the growth factor synthesized was not significantly changed by lead. Although the binding of [125I]bFGF to heparan sulfate proteoglycans can be directly inhibited by lead, the inhibition was not so marked. On the other hand, lead markedly suppressed the incorporation of [35S]sulfate into heparan sulfate accumulated in the cell layer and the conditioned medium, suggesting that the metal inhibited the synthesis of the glycosaminoglycan in growing endothelial cells. Inhibition of the [3H]thymidine incorporation by lead was significantly restored by heparin. Since the binding of bFGF to its receptor is strongly promoted by heparan sulfate, the present data suggest that lead inhibits vascular endothelial cell proliferation by induction of a lower response to endogenous bFGF through a suppression of heparan sulfate synthesis.

Lead inhibits the core protein synthesis of a large heparan sulfate proteoglycan perlecan by proliferating vascular endothelial cells in culture

We characterized proteoglycans synthesized by growing cultured bovine aortic endothelial cells after exposure to lead. Lead significantly decreased the incorporation of both [3H]glucosamine and [35S]sulfate into glycosaminoglycans accumulated in the cell layer and the conditioned medium of the cells in a dose-dependent manner. Proteoglycans metabolically labeled with [35S]sulfate in the presence of lead were separated into heparan sulfate proteoglycans (HSPGs) and more highly charged chondroitin/dermatan sulfate proteoglycans by DEAE-Sephacel ion-exchange chromatography. It was found that lead markedly inhibited the synthesis of HSPGs. Sepharose CL-4B molecular sieve gel filtration showed that the marked decrease by lead occurred in the high molecular weight subclass of HSPGs. However, the length of heparan sulfate chains (approximately 50 kDa) was unchanged when analyzed by Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of core proteins showed that lead reduced the accumulation of a high molecular weight (approximately 400 kDa) HSPG core protein in the cell layer and the conditioned medium; the core protein was identified as a perlecan core by Western blot analysis. It is suggested that lead inhibits the synthesis of the perlecan core protein in growing endothelial cells without a change of heparan sulfate chain length. The present data support the hypothesis that inhibition of endothelial cell proliferation by lead may result from a lower response of the cells to endogenous basic fibroblast growth factor whose binding to the receptor is strongly promoted by heparan sulfate chains of perlecan.

The effect of lithium on methamphetamine-induced regional Fos protein expression in the rat brain

Lithium has been used widely for the treatment of manic states. Since amphetamines produce effects in humans similar to the symptoms of idiopathic mania, amphetamine administration to animals has been proposed as a model of this condition. To investigate the neurobiologic substrates of the antimanic effects of chronic lithium administration, we investigated its effects on methamphetamine-induced regional Fos protein expression in the rat brain. Chronic lithium administration (14 days; serum lithium concentration, 0.41+/-0.02 mEq/l) significantly reduced the number of neuronal nuclei showing immunoreactivity induced by methamphetamine (2mg/kg) in the prefrontal cortex, caudate/putamen, nucleus accumbens, and central nucleus of the amygdala. These results indicate the structural basis in CNS which is responsible for the antimanic effect of lithium.

An antitumor promoter from Moringa oleifera Lam

In the course of studies on the isolation of bioactive compounds from Philippine plants, the seeds of Moringa oleifera Lam. were examined and from the ethanol extract were isolated the new O-ethyl-4-(alpha-L-rhamnosyloxy)benzyl carbamate (1) together with seven known compounds, 4(alpha-L-rhamnosyloxy)-benzyl isothiocyanate (2), niazimicin (3), niazirin (4), beta-sitosterol (5), glycerol-1-(9-octadecanoate) (6), 3-O-(6'-O-oleoyl-beta-D-glucopyranosyl)-beta-sitosterol (7), and beta-sitosterol-3-O-beta-D-glucopyranoside (8). Four of the isolates (2, 3, 7, and 8), which were obtained in relatively good yields, were tested for their potential antitumor promoting activity using an in vitro assay which tested their inhibitory effects on Epstein-Barr virus-early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). All the tested compounds showed inhibitory activity against EBV-EA activation, with compounds 2, 3 and 8 having shown very significant activities. Based on the in vitro results, niazimicin (3) was further subjected to in vivo test and found to have potent antitumor promoting activity in the two-stage carcinogenesis in mouse skin using 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and TPA as tumor promoter. From these results, niazimicin (3) is proposed to be a potent chemo-preventive agent in chemical carcinogenesis.

High-level expressing YAC vector for transgenic animal bioreactors

The position effect is one major problem in the production of transgenic animals as mammary gland bioreactors. In the present study, we introduced the human growth hormone (hGH) gene into 210-kb human alpha-lactalbumin position-independent YAC vectors using homologous recombination and produced transgenic rats via microinjection of YAC DNA into rat embryos. The efficiency of producing transgenic rats with the YAC vector DNA was the same as that using plasmid constructs. All analyzed transgenic rats had one copy of the transgene and produced milk containing a high level of hGH (0.25-8.9 mg/ml). In transgenic rats with the YAC vector in which the human alpha-lactalbumin gene was replaced with the hGH gene, tissue specificity of hGH mRNA was the same as that of the endogenous rat alpha-lactalbumin gene. Thus, the 210-kb human alpha-lactalbumin YAC is a useful vector for high-level expression of foreign genes in the milk of transgenic animals.

Enhancement of the anti-tumor effect of 5'-deoxy-5-fluorouridine by transfection of thymidine phosphorylase gene into human colon cancer cells

Thymidine phosphorylase (dThdPase) is an enzyme that converts 5'-deoxy-5-fluorouridine (5'DFUR) to the toxic substance 5-fluorouracil (5-FU); it is also known to be a platelet-derived endothelial cell growth factor. In order to investigate the feasibility of suicide gene therapy against colorectal cancer by means of the combination of 5'DFUR and the converting enzyme dThdPase, we transfected the dThdPase gene into the human colon cancer cell line SW480 and analyzed the growth pattern as well as the sensitivity to 5-FU or 5'DFUR of the dThdPase-transfected cells. The 50% inhibition (IC50) values of 5-FU against the SW480 parental cells, control vector-transfected cells SW480/V1, and dThdPase-transfected cells SW480/dThdPase were approximately 4.9, 6.3, and 2.9 microM, respectively. The IC50 of SW480/dThdPase was lower than that of SW480 or SW480/V1, although the differences were not statistically significant. The IC50 values of 5'DFUR for SW480, SW480/V1, and SW480/dThdPase were approximately 300, 330, and 3.2 microM, respectively. The sensitivity to 5'DFUR of SW480/dThdPase was increased by about 100-fold compared with that of SW480 or SW480/V1. With only 10% transfection efficacy, a high enough sensitivity to 5'DFUR was obtained to suppress the cell growth, indicating that a strong bystander effect was induced by this system. The in vivo growth of the s.c. transplanted SW480/dThdPase tumor in nude mice was significantly suppressed by i.p. injection of 5'DFUR compared with that in control mice that received phosphate-buffered saline (PBS) treatment. These results suggest that gene therapy using the combination of 5'DFUR and the dThdPase gene may be a useful approach for treatment of colon cancer.

Induction of gamma-glutamylcysteine synthetase gene expression by platinum drugs in peripheral mononuclear cells of lung cancer patients

BACKGROUND

To investigate in vivo the roles of gamma-glutamylcysteine synthetase (gamma-GCS), multidrug resistance-associated protein (MRP), human canalicular multispecific organic anion transporter (cMOAT) and DNA topoisomerase I (topo I) in relation to platinum drug resistance, we monitored the changes of the steady-state levels of the mRNAs for these factors in peripheral mononuclear cells (PMN) after completing platinum drug administration.

PATIENTS AND METHODS

PMN from 46 subjects were studied. We obtained PMN from 14 previously untreated lung cancer patients and 14 normal volunteers to measure the baseline gene expression levels. We then obtained PMN from 18 patients with previously untreated advanced lung cancer before and after they received platinum drug treatment. We analyzed the gene expression levels by using the quantitative reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

There were no differences in the baseline expression levels between normal volunteers and lung cancer patients in any of the genes. After platinum drug administration, the heavy subunit of gamma-GCS (gamma-GCSh) expression level increased 2.5-fold within 24 hours and the increase persisted for a month, whereas the light subunit of gamma-GCS (gamma-GCSl) expression level did not show an early response but had increased after a month. By contrast, the MRP, cMOAT and topo I expression levels were similar before, during and after chemotherapy.

CONCLUSIONS

These results suggest that the gene expression levels of both subunits of gamma-GCS play an important in vivo role in platinum drug resistance.

Plasma DNA microsatellites as tumor-specific markers and indicators of tumor progression in melanoma patients

Multiple DNA microsatellites with frequent loss of heterozygosity (LOH) in melanomas have been demonstrated. The finding that free DNA is enriched in blood of melanoma patients prompted studies to determine whether tumor-specific DNA, such as DNA microsatellites exhibiting LOH, can be detected in blood and have clinical use. In this study, 57 advanced and 19 early clinically staged melanoma patients were assessed using 10 microsatellite markers on six chromosomes. Matched plasma and melanoma tissues from 40 patients showed significant concordance of LOH (P < 0.0001). The frequency of LOH microsatellite markers detected in plasma significantly increased in more advanced-staged patients. At locus D3S1293, LOH detection showed significant correlation to clinical disease progression (P = 0.02). Additionally, the combination of LOH microsatellite markers D9S157 and D3S1293 (P = 0.01), D9S157 and D1S228 (P = 0.05), and D11S925 and D3S1293 (P = 0.01) were significantly correlated to progression of different clinical stages of disease. These studies indicate that tumor-specific LOH markers in plasma have a potential clinical use as diagnostic and prognostic markers in melanoma patients.

Transferrin receptor is necessary for development of erythrocytes and the nervous system

Plasma iron circulates bound to transferrin (Trf), which solubilizes the ferric ion and attenuates its reactivity. Diferric Trf interacts with cell-surface Trf receptor (Trfr) to undergo receptor-mediated endocytosis into specialized endosomes. Endosomal acidification leads to iron release, and iron is transported out of the endosome through the activity of divalent metal transporter 1 (DMT1, formerly Nramp2), a transmembrane iron transporter that functions only at low pH. Trf and Trfr then return to the cell surface for reuse, completing a highly efficient cycle. Although the Trf cycle is assumed to be the general mechanism for cellular iron uptake, this has not been validated experimentally. Mice with hypotransferrinaemia (hpx) have little or no plasma Trf. They have severe anaemia, indicating that the Trf cycle is essential for iron uptake by erythroid cells. Other hpx tissues, however, are generally normal, and there is a paradoxical increase in intestinal iron absorption and iron storage. To test the hypothesis that the Trf cycle has unique importance for erythropoiesis, we disrupted the Trfr gene in mice. This results in elimination of the Trf cycle, but leaves other Trf functions intact. Mice lacking Trfr have a more severe phenotype than hpx mice, affecting both erythropoiesis and neurologic development. Furthermore, haploinsufficiency for Trfr results in impaired erythroid development and abnormal iron homeostasis.

Mitochondrial and intracellular free-calcium regulation of radiation-induced apoptosis in human leukemic cells

PURPOSE

To investigate the mechanisms and pathways of X-ray apoptosis in Molt-4 cells, focusing on mitochondrial and cytosolic Ca2+ ([Ca2+]i) regulation.

MATERIALS AND METHODS

X-irradiated Molt-4 cells and cell extract (CE) were used to analyse: (1) induced apoptosis (Giemsa stain), (2) p53, Bcl-2 and Bax expressions (immunoblot), (3) mitochondrial potential deltapsi(m) and (4) [Ca2+]i (flow cytometry), (5) caspase-3 activity, and (6) roles of [Ca2+]- and caspase-3-mediated pathways by inhibiting either or both pathways for induced apoptosis.

RESULTS

Molt-4 cells were sensitive to apoptosis since 5 Gy induced 57 and 94% apoptosis at 6 and 24 h. After 5Gy, p53 was accumulated that upregulated Bax but which repressed Bcl-2 with time, resulting in a 7-fold increase in Bax/Bxl-2 at 6 h. Predominant Bax reduced deltapsi(m), and low-deltapsi(m) cells increased 45 min earlier than apoptosis after 5 Gy. Caspase-3 was activated in apoptotic CE. The caspase-3 inhibitor Ac-DEVD-CHO inhibited apoptosis and DNA-ladder formation by approximately 50%, suggesting a approximately 50% role of caspase-3-activated DNase (CAD). [Ca2+]i was increased after 5 Gy. [Ca2+]i-chelating BAPTA-AM (5 microM) and/or DNase gamma-inhibiting Zn2+ (0.5 mM) inhibited approximately 50% of induced apoptosis and DNA-laddering, indicating a 50% participation of Ca2+/Mg2+-dependent DNase gamma.

CONCLUSIONS

The p53-Bax-mitochondria-caspase-3-CAD pathway and the [Ca+2]i-mediated DNase gamma pathway were involved in the regulation of X-ray apoptosis in sensitive Molt-4 cells.

Intersections between blood cell development and leukemia genes

Hematopoietic development is regulated in large part by transcription factors that control cell fate decisions and cellular differentiation. Several genes first discovered in the context of chromosomal translocations in leukemia also serve important functions in blood cell development. Gene-targeting experiments related to two of these factors, SCL/tal-1 and translocation-ets-leukemia (TEL), are reviewed here. SCL/tal-1, a T-cell basic helix-loop-helix oncoprotein, is required for the formation of all hematopoietic lineages. In addition, it is essential for angiogenesis in the yolk sac, indicating a dual function in blood and vessel development. TEL, an ets-related factor which is translocated to a variety of other genes in leukemias, is also required for proper angiogenesis in the yolk sac. Additional studies, however, demonstrate that TEL function is necessary for hematopoiesis to be established in the bone marrow microenvironment. These studies emphasize the intrinsic roles of leukemia-associated transcription factors in normal blood cell and vessel development.

Circulating thrombomodulin and hematological alterations in type 2 diabetic patients with retinopathy

To clarify the relationship between circulating thrombomodulin (TM) and endothelial cell damage in diabetes mellitus, plasma levels of TM were quantitated by an enzyme linked immunoabsorbant assay (ELISA) in 164 type 2 diabetes mellitus and 72 normal control subjects, and these levels were compared with those of von Willebrand factor antigen (vWf: Ag), thrombin antithrombin III complexes (TAT), plasmin-alpha2-plasmin inhibitor complexes (PIC), fibrinogen, D-dimer, urinary albumin excretion rate (AER), intima-media thickness (IMT) and plaque score of the common carotid artery assessed with high resolution B-mode ultrasonography. Plasma levels of TM, vWf: Ag, TAT, PIC, AER, IMT and plaque score were significantly increased in the diabetic patients compared to the normal control subjects. Plasma TM levels showed significant correlation with vWf: Ag (r=0.350, p<0.0001), TAT (r = 0.334, p < 0.0001), PIC (r = 0.450, p < 0.0001), AER (r = 0.334, p < 0.0001), IMT (r = 0.181, P<0.01), plaque score (r=0.385, p<0.0001). Among four groups of diabetic patients, divided based on their severity of diabetic retinopathy, there were no significant differences in age, sex, systolic and diastolic blood pressure levels, HbA,1c, or plasma lipid levels, although the plasma levels of TM, vWf: Ag, TAT, PIC, AER, IMT and the plaque score in the patients with proliferative retinopathy were significantly higher than those of the healthy controls and patients with simple retinopathy. Among the 43 normoalbuminuric patients without intima-media thickness or thickened plaque (AER<30 mg/g Creatinine, IMT<1.0 mm, plaque score = 0), plasma levels of TM, vWf: Ag, TAT, PIC were significantly higher in those patients with retinopathy than in those without retinopathy. Multivariate analysis showed TM, TAT and PIC levels to be independent predictors of diabetic retinopathy. In conclusion, circulating TM reflects endothelial cell damage in patients with diabetic retinopathy, and hypercoagulability might play an important role in endothelial cell damage.

Effects of isoflurane anesthesia on pulmonary vascular response to K+ ATP channel activation and circulatory hypotension in chronically instrumented dogs

BACKGROUND

The objective of this study was to evaluate the effects of isoflurane anesthesia on the pulmonary vascular responses to exogenous adenosine triphosphate-sensitive potassium (K+ ATP) channel activation and circulatory hypotension compared with responses measured in the conscious state. In addition, the extent to which K+ ATP channel inhibition modulates the pulmonary vascular response to circulatory hypotension in conscious and isoflurane-anesthetized dogs was assessed.

METHODS

Fifteen conditioned, male mongrel dogs were fitted with instruments for long-term monitoring to measure the left pulmonary vascular pressure-flow relation. The dose-response relation to the K+ ATP channel agonist, lemakalim, and the pulmonary vascular response to circulatory hypotension were assessed in conscious and isoflurane-anesthetized (approximately 1.2 minimum alveolar concentration) dogs. The effect of the selective K+ ATP channel antagonist, glibenclamide, on the pulmonary vascular response to hypotension was also assessed in conscious and isoflurane-anesthetized dogs.

RESULTS

Isoflurane had no effect on the baseline pulmonary circulation, but it attenuated (P<0.05) the pulmonary vasodilator response to lemakalim. Reducing the mean systemic arterial pressure to approximately 50 mm Hg resulted in pulmonary vasoconstriction (P<0.05) in the conscious state, and this response was attenuated (P<0.05) during isoflurane. Glibenclamide had no effect on the baseline pulmonary circulation, but it potentiated (P<0.05) the pulmonary vasoconstrictor response to hypotension in conscious and isoflurane-anesthetized dogs.

CONCLUSIONS

These results indicate that K+ ATP-mediated pulmonary vasodilation and the pulmonary vasoconstrictor response to hypotension are attenuated during isoflurane anesthesia. Endogenous K+ ATP channel activation modulates the pulmonary vasoconstrictor response to hypotension in the conscious state, and this effect is preserved during isoflurane anesthesia.

A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.

FOG-2: A novel GATA-family cofactor related to multitype zinc-finger proteins Friend of GATA-1 and U-shaped

GATA factors are transcriptional regulatory proteins that play critical roles in the differentiation of multiple cell types in both vertebrates and invertebrates. Recent evidence suggests that the biological activities of both mammalian and Drosophila GATA factors are controlled in part by physical interaction with multitype zinc-finger proteins, Friend of GATA-1 (FOG) and U-shaped (Ush), respectively. Here we describe a new FOG-related polypeptide, designated FOG-2, that is likely to participate in differentiation mediated by GATA factors in several tissues. Expression of FOG-2 mRNA differs from that of FOG and is largely restricted to heart, neurons, and gonads in the adult. Somewhat broader expression is evident during mouse embryonic development. Similar to FOG and Ush, FOG-2 protein interacts specifically with the amino finger of GATA factors in the yeast two-hybrid system and in mammalian cells. Remarkably, though FOG-2 is quite divergent from FOG in its primary sequence, forced expression of FOG-2 rescues terminal erythroid maturation of FOG-/- hematopoietic cells. Thus, members of the FOG family of cofactors share highly specific association with GATA factors and are substantially interchangeable with respect to some aspects of function in vivo. The interaction of GATA and FOG family members constitutes an evolutionarily conserved paradigm for transcriptional control in differentiation and organogenesis.