[Impact of nitric oxide on endothelin gene expression in intrapulmonary arteries of chronic hypoxic rats]

OBJECTIVE

To investigate the impact of nitric oxide on endothelin-1 (ET-1) mRNA expression in pulmonary artery endothelial cells and pulmonary artery smooth muscle cells of chronic hypoxic rats.

METHODS

In situ hybridization was performed on lung sections from 40 chronic hypoxic rats treated either with L-Arginine (L-Arg) or N omega-nitro-L-arginine methyl ester (L-NAME) by using cRNA probe for ET-1.

RESULTS

Most intrapulmonary arteries had 1%-50% of the endothelial cells expressing ET-1 mRNA in both one-week and two-week hypoxic rats (75% +/- 3% and 71% +/- 6%, respectively), which was significantly inhibited by L-Arg but augmented by L-NAME administration. Most pulmonary artery smooth muscle cells showed no ET-1 mRNA signals in both one-week and two-week hypoxic rats (85% +/- 6% and 98% +/- 2%, respectively). However, L-NAME increased ET-1 mRNA expression in pulmonary artery smooth muscle cells of hypoxic rats.

CONCLUSION

Nitric oxide inhibited ET gene expression in both pulmonary artery endothelial cells and smooth muscle cells of rats exposed to chronic hypoxia.

Presence of functional NMDA receptors in a human neuroblastoma cell line

Data are presented that provide convincing evidence for the expression of structurally normal and functional NMDA receptors by acetylcholine-producing human LA-N-2 neuroblastoma cells in culture. Reverse transcription and polymerase chain reaction (RT-PCR), followed by cloning and DNA sequencing, revealed the presence in these cells of mRNA representing the key subunit, NMDAR1, of the receptor. This mRNA was further demonstrated by Northern analysis to be the same size as that described for human neurons. The neutral red cytotoxicity assay was utilized to examine the influence on these neuroblastoma cells of a 48-h incubation with either L-glutamic acid or the specific NMDA agonist N-phthalamoyl-L-glutamic acid (NPG). Cell cytotoxicity was shown by this assay to be increased through incubation with glutamate at 1 and 10 mM by 27 and 37%, and through incubation with NPG at 0.1 and 1 mM by 28 and 46%. A possible mechanism of these toxic effects was further evaluated using the whole-cell configuration of the patch-clamp technique and the specific NMDA agonists (+/-)1-aminocyclobutane-cis-1,3-dicarboxylic acid (ACDA) and NPG. Using this procedure, a voltage-dependent tetrodotoxin-sensitive inward sodium current was found to be increased (x 1.5) by L-glutamic acid and by both NMDA agonists in the presence of glycine. Another voltage-gated inward current, probably carried by calcium ions, was increased three- to fourfold. Hence, these glutamate activities observed in human LA-N-2 neuroblastoma cells appear to occur through the activation of functional NMDA receptors in much the same way as reported for neurons, and both glutamate and NMDA agonists can be toxic to these neuroblastoma cells. Our findings, therefore, suggest this cell line will provide a model suitable for investigating the mechanisms of NMDA-related long-term potentiation (LTP) in neurons and of the NMDA-related neurotoxic effects of glutamate in disease states that involve a reduction in cholinergic function.

Ultrasonographic diagnosis of hemangiomas of soft tissue

Presented in this paper are the results of ultrasonic examination in 29 cases of hemangiomas of soft tissue. Out of the 29 cases, 20 lesions were revealed as heterogeneous echoic masses; 6 as anechoic areas and 3 as solid masses. Hyperechoic foci of calcifications or phlebolithes were detected in 16 cases. Intramuscular hemangiomas were sonographically diagnosed in 15 patients; hemangiomas of soft tissue in 8, pseudoaneurysm in 3; deformity of the arteriovenous fistula in 1 and hemangiosarcoma in 2. The diagnosis in 28 patients were surgically and pathologically confirmed and the remaining one was confirmed by aspiration and cytological examination. The diagnostic accuracy of the ultrasound was 100%.

Functional vasopressin V1 type receptors are present in variant as well as classical forms of small-cell carcinoma

Vasopressin and other neuropeptides are believed to serve as autocrine growth factors for small-cell carcinoma of the lung (SCCL), and these mitogenic influences are reported to involve increases in intracellular Ca2+. Of the classical and variant forms of SCCL, the latter is not only more drug-resistant but also refractory to vasopressin, and other peptides, with respect to changes in intracellular Ca2+. It is currently unclear if this refractiveness of variant SCCL is due to the absence of involved peptide receptors, to the production of abnormal receptors, or to abnormalities in components of induced transduction cascades. In this study, the presence of structurally-normal and functional vasopressin V1a receptors, was examined in a classical SCCL cell line (NCI H345) that is Ca(2+)-responsive to vasopressin, and a variant SCCL cell line (NCI H82) that is unresponsive in this regard to the peptide. Both cell lines were shown to express an mRNA of 1.9 Kb for the vasopressin V1a receptor. RT-PCR, cloning, and DNA sequencing revealed the structure of the mRNA was identical for both cell lines, and, in turn, identical to the mRNA expressed for this receptor by human liver cells. In both cell lines and liver, this mRNA was shown by Western analysis and RIA to generate major protein products of approximately 70,000 and 43,000 daltons. Vasopressin action on NCI H82 cells resulted in a substantial rise in the levels of total inositol phosphates. However, it was reaffirmed that these changes in inositol phosphates were not accompanied by a rise in Ca2+ levels. All of these data indicate that variant SCCL, as well as classical SCCL, expresses structurally-normal and functional vasopressin V1a receptors, but their activation in variant SCCL raises IP3 levels without a corresponding rise in intracellular Ca2+. This difference between the two SCCL sub-types therefore involves either steps in the inositol triphosphate cascade beyond the activation of phospholipase C, or alternatively, components of other transduction events that might be involved with changes in intracellular Ca2+.

Effect of intra-arachnoid space perfusion on thromboxane A and prostacycline in experimental spinal cord injury

In order to understand the relation between TXA2-PGI2 and secondary trauma and the effect of intra-arachnoid perfusion of dexamethasone and verapamil on alteration of TXA2-PGI2 following spinal cord injury, TXB2 and 6-keto-PGF alpha concentration and pathological changes in injured site 1, 2, 4, and 6 h after injury were studied using a rabbit spinal cord injury model by Allen's weight drop method.

A new drug delivery system--ciprofloxacine/tricalcium phosphate delivery capsule (CTDC) and its in vitro drug release pattern

A new drug delivery system (DDS), ciprofloxacine/tricalcium phosphate delivery capsule (CTDC) was developed by loading a broad-spectrum antibiotic ciprofloxacine into the central cylindrical cavity of tricalcium phosphate capsule. The new system showed good biocompatibility and could degrade gradually in our preliminary studies. In vitro study showed that CTDC could maintain high-level and long-term release of ciprofloxacine and that ultrasonic irradiation within the range of physical therapy could increase the drug release amount from CTDC ( P < 0.02), and might become a new technique to achieve the control of drug release from DDS.

Tissue response and the cytoconduction ability to collagen/hydroxyapatite heterotopic implantation

A histological and ultrastructural observation of CHA implanted intramuscularly and subcutaneously had been reported. Our results showed that a mild inflammation developed at the early stage and disappeared 2 weeks after implantation. The infiltrating cells were mainly monocyte-macrophages, a number of fibroblasts followed macrophages closely. It was possible that as CHA degrades, monocyte-macrophages continuously released inflammatory factors, thus enhancing fibroblast proliferation activity and tissue regeneration. In addition, the heterotopic calcification of collagen matrix was observed, suggesting that CHA promoted calcification deposition.

A model of subarachnoid cavity drugs perfusion and its clinical application in treatment of spinal cord injury

An animal model of subarachnoid cavity drugs perfusion and its prelimilary clinical application in treatment of acute spinal cord injury (SCI) were reported. Analysis of the heart rate (HR), ECG blood pressure (CVP, CAP) cerebrospinal fluid (CSF) pressuer and CSF gas and pH values of 10 healthy adult goats during subarachnoid daxamethasone verapamil perfusion showed that this model was safe anti reliable. 26 patients with acute SCI were selected for a clinical obseration. Good results were obtained in 7 cases who received this treatment of subarachnoid cavity perfusion with dexamethasone and verapamil.

RSC, an essential, abundant chromatin-remodeling complex

A novel 15-subunit complex with the capacity to remodel the structure of chromatin, termed RSC, has been isolated from S. cerevisiae on the basis of homology to the SWI/SNF complex. At least three RSC subunits are related to SWI/SNF polypeptides: Sth1p, Rsc6p, and Rsc8p are significantly similar to Swi2/Snf2p, Swp73p, and Swi3p, respectively, and were identified by mass spectrometric and sequence analysis of peptide fragments. Like SWI/SNF, RSC exhibits a DNA-dependent ATPase activity stimulated by both free and nucleosomal DNA and a capacity to perturb nucleosome structure. RSC is, however, at least 10-fold more abundant than SWI/SNF complex and is essential for mitotic growth. Contrary to a report for SWII/SNF complex, no association of RSC (nor of SWI/SNF complex) with RNA polymerase II holoenzyme was detected.

Nitric oxide promotes medial preoptic dopamine release during male rat copulation

Dopamine (DA) is released in the medial preoptic area (MPOA) of male rats during copulation. DA agonists infused into the MPOA facilitate, and antagonists impair, copulatory behavior. Local administration of the nitric oxide (NO) precursor L-arginine also increases DA release in the MPOA. The present experiment used microdialysis to test whether NO promotes DA release during copulation. Males received either an NO synthesis inhibitor, nitro-L-arginine methyl ester (L-NAME, 400 microM), or its inactive isomer D-NAME (400 microM) into the MPOA via a microdialysis probe for 3 h prior to the introduction of a female. Following D-NAME administration, DA increased during copulation, while L-NAME prevented this increase. NO may therefore promote DA release in the MPOA of male rats, thereby facilitating copulation.

Electrophysiological and morphological properties of neurons acutely isolated from the rostral gustatory zone of the rat nucleus of the solitary tract

The biophysical and morphological characteristics of acutely isolated neurons from the rostral nucleus of the solitary tract (rNST) were investigated under current clamp conditions and compared with the results obtained from neurons recorded in brain slices. The passive membrane properties of the isolated neurons were similar to rNST neurons in brain slices and the neurons maintained their morphological characteristics although their dendritic tree was truncated. The isolated neurons also retained their characteristic repetitive firing properties. In addition we also noted developmental changes in the intrinsic membrane properties of the isolated neurons, such as a shortening in action potential duration, decrease in membrane time constant and input resistance, that occurred when these parameters were compared in neurons isolated from young (5-10 days) and older animals. These enzymatically dispersed neurons therefore retained both the membrane properties and morphology observed in the intact brainstem and in vitro brain slice preparation. The use of this isolated neuron preparation provides a basis for further study of rNST neurobiology.

[Rapid and simple detection of Ki-ras gene mutations in pancreatic adenocarcinoma by PCR-SSP]

In order to judge whether Ki-ras gene mutations are present and their mutation styles, three kinds of special sequence primers (SSP) for polymerase chain reaction with regard to the mutant styles (CGT, GTT and GAT) at codon 12 were used to study the mutations in frozen tissues of pancreatic adenocarcinoma. The amplification products were studied with conventional electrophoresis using acrylamide gels and stained with ethidium bromide to detect the mutations.

RESULTS

In 23 of 25 frozen pancreatic adenocarcinoma specimens, Ki-ras genes with mutations at codon 12 were found; 2 mutant styles were found in 8 of the 23 samples; no mutations were found in 11 normal pancreatic tissues, 12 benign pancreatic disease tissues and 3 bile duct carcinoma tissues. This method is rapid, convenient, specific as well as sensitive. We conclude that this may become a valuable diagnostic modality for pancreatic carcinoma and for differentiating benign pancreatic diseases from carcinoma.

Simultaneous Production and Recovery of Fumaric Acid from Immobilized Rhizopus oryzae with a Rotary Biofilm Contactor and an Adsorption Column

An integrated system of simultaneous fermentation-adsorption for the production and recovery of fumaric acid from glucose by Rhizopus oryzae was investigated. The system was constructed such that growing Rhizopus mycelia were self-immobilized on the plastic discs of a rotary biofilm contactor during the nitrogen-rich growth phase. During the nongrowth, production phase, the biofilm was alternately exposed to liquid medium and air upon rotation of the discs in the horizontal fermentation vessel. The product of fermentation, fumaric acid, was removed simultaneously and continuously by a coupled adsorption column, thereby moderating inhibition, enhancing the fermentation rate, and sustaining cell viability. Another beneficial effect of the removal of fumaric acid is release of hydroxyl ions from a polyvinyl pyridine adsorbent into the circulating fermentation broth. This moderates the decrease in pH that would otherwise occur. Polyvinyl pyridine and IRA-900 gave the highest loading for this type of fermentation. This fermentation system is capable of producing fumaric acid with an average yield of 85 g/liter from 100 g of glucose per liter within 20 h under repetitive fed-batch cycles. On a weight yield basis, 91% of the theoretical maximum was obtained with a productivity of 4.25 g/liter/h. This is in contrast to stirred-tank fermentation supplemented with calcium carbonate, whose average weight yield was 65% after 72 h with a productivity of 0.9 g/liter/h. The immobilized reactor was operated repetitively for 2 weeks without loss of biological activity.

Structure--activity relationships of 1-(2-Deoxy-2-fluoro-beta-L-arabinofuranosyl)pyrimidine nucleosides as anti-hepatitis B virus agents

Since 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil (L-FMAU) has been shown to be a potent anti-HBV agent in vitro, it was of interest to study the structure-activity relationships of related nucleosides. Thus, a series of 1-(2-deoxy-2-fluoro-beta-L-arabinofuranosyl)pyrimidine nucleosides have been synthesized and evaluated for antiviral activity against HBV in 2.2.15 cells. For this study, L-ribose was initially used as the starting material. Due to the commercial cost of L-ribose, we have developed an efficient procedure for the preparation of L-ribose derivative 6. Starting from L-xylose, 6 was obtained in an excellent total yield (70%) through the pyridinium dichromate oxidation of the 3-OH group followed by stereoselective reduction with NaBH4. It was further converted to the 1,3,5-tri-O-benzoyl-2-deoxy-2-fluoro-alpha-L-arabinofuranose (10), which was then condensed with various 5-substituted pyrimidine bases to give the nucleosides. Among the compounds synthesized, the lead compound, L-FMAU (13), exhibited the most potent anti-HBV activity (EC50 0.1 microM). None of the other uracil derivatives showed significant anti-HBV activity up to 10 microM. Among the cytosine analogues, the cytosine (27) and 5-iodocytosine (35) derivatives showed moderately potent anti-HBV activity (EC50 1.4 and 5 microM, respectively). The cytotoxicity of these nucleoside analogues has also been assessed in 2.2.15 cells as well as CEM cells. None of these compounds displayed any toxicity up to 200 microM in 2.2.15 cells. Thus, compound 13 (L-FMAU), 27, and 35 showed a selectivity of over 2000, 140, and 40, respectively.

[Mannital induced acute renal failure]

14 cases of mannitol-induced acute renal failure were reported. The dosage of mannitol used varied widely. In all cases serum Na+, HCO3- were decreased, K+ and BUN increased significantly. Serum osmolality was measured in 5 cases. The osmolal gap was increased greatly, 77.4mOsm/kg. H2O in average. The increase of osmolal gap may play an important role in acute renal failure by causing intensive renal vasocontraction. Monitoring of serum osmolality or osmolal gap can help to prevent mannitol intoxication. The decrease of serum Na+ may be a warning sign of increased osmolal gap. Hemodialysis is the best way for the treatment of mannitol-induced acute renal failure.

Repeated recurrence of osteosarcoma treated by resections and chemotherapy

This paper presents 5 patients with repeated recurrence of osteosarcoma (RROS). The primary focus of 3 patients were in the distal portion of femur, and 2 patients were in the proximal portion of tibia. Three patients, whose chest X ray film were negative, were treated by amputation and chemotherapy. Two patients had isolated metastatic focus 1.5 cm in diameter in lung, were treated by amputation after 1 week of chemotherapy and then treated by lobectomy after 2 weeks of chemotherapy. After operation, the chemotherapy was carried out for 3 courses of treatment. The roentgenogram of chest and affected limb were taken once every two months. There were metastatic focuses found in the lung of 1 patient and in the distal portion of femur of 2 patients. One patient was operated on for 4 times. Up to now, 3 patients have been living for 5 years and 2 patients for 6 years after operation.

Effect of acute feeding of diets of varying fatty acid composition on intestinal apolipoprotein expression in the newborn swine

The purpose of this study was to determine the effects of dietary fatty acids of varying chain lengths and degrees of saturation on intestinal apolipoprotein (apo) B and A-I expression in the newborn piglet. Two-day-old female piglets received one of three isocaloric formulas containing 48% of total calories (120 kcal/kg/24 h) as medium-chain triglycerides (MCT) from MCT oil, intermediate-chain saturated triglycerides (ICST) from coconut oil, or long-chain polyunsaturated triglycerides (LCPUT) from safflower oil by continuous duodenal infusion for 24 h. After in situ radiolabeling, jejunal and ileal mucosal apo B-48 and A-I were immunoprecipitated, and synthesis was expressed as percentage of total protein synthesis. Mucosal apo B and A-I mass was measured by ELISA as nanograms of apoprotein/microgram of total protein. Fifty percent less apo B jejunal synthesis was present in the ICST group versus the MCT and LCPUT groups (0.67 +/- 0.07, 1.19 +/- 0.20, and 1.25 +/- 0.15, respectively, mean +/- SEM, p < 0.05). Jejunal apo B mass was lower in the MCT group versus the ICST and LCPUT groups (0.10 +/- 0.02, 0.21 +/- 0.03, and 0.16 +/- 0.03, respectively, p < 0.05). Ileal apo B synthesis was lowest in the ICST group. No differences were found in ileal apo B mass. Two-fold higher jejunal apo A-I synthesis was found in the LCPUT group versus the MCT and ICST groups (14.18 +/- 1.69, 7.56 +/- 2.63, and 6.36 +/- 0.58, respectively, p < 0.01). No differences were found for jejunal apo A-I mass. In the ileum, the only difference was a higher apo A-I mass in the LCPUT group (p < 0.05). We conclude that in the newborn piglet intestinal apo B and A-I expression is acutely and differentially regulated by dietary lipid varying in fatty acid chain length and saturation. The patterns of regulation are complex and vary among specific apolipoproteins and regions of the small intestine and include co- and posttranslational mechanisms.

Osmotic properties of boar spermatozoa and their relevance to cryopreservation

A series of six experiments was conducted to determine the fundamental cryobiological properties of boar spermatozoa to develop optimal approaches for cryopreserving this important cell type. In the first experiments, boar spermatozoa samples were diluted in various osmolalities of experimental solutions (185-900 mOsmol kg-1) to provide hypo-, iso-, and hyperosmotic conditions. Equilibrium cell volumes (Expts 1 and 2) were measured after exposure for 3 min and the change in cell volume was measured over time using an electronic particle counter (Expt 3). The isosmotic cell volume was found to be 26.3 +/- 0.39 microns 3 (mean +/- SEM; n = 5). Over this range of osmolalities, boar spermatozoa behaved as linear osmometers (a linear volume versus 1/osm plot, r2 = 0.99) with an osmotically inactive cell fraction of 67.4 +/- 4.5%. The rate of water permeability (Lp) was determined to be 1.03 +/- 0.05 microns min-1 atm-1, which was consistent within and among donors (P > 0.130). A second series of experiments was performed to determine the effect of temperature and osmolality on boar sperm motility (Expt 4), and the effect of osmolality on the integrity of the sperm plasma membrane and its temperature dependence. Plasma membrane integrity was measured before and after boar spermatozoa were returned to an isosmolality (Expt 6). Motility was not affected at 30 degrees C, relative to that at room temperature, but was significantly decreased (P < 0.05) at 8 degrees C and 0 degree C (yielding a relative reduction to 85% and 35% of original motility, respectively; n = 6). Sperm motility was not significantly decreased (P > 0.05) until the osmolality reached 210 mOsmol kg-1, at which time motility began to decrease from 95% to 10% of the original value at 90 mOsmol kg-1. The integrity of the plasma membrane of boar spermatozoa was found to be dependent on temperature, donor and osmolality, decreasing significantly (P < 0.05) below room temperature, and below 185 mOsmol kg-1 (P < 0.05). There was no significant difference (P > 0.10) in the integrity of the plasma membrane of the samples before and after returning to 290 mOsmol kg-1, indicating that osmotic damage occurs during the initial change from isosmotic to hyposmotic media. These osmotic characteristics could be used to determine optimal conditions for cryopreservation of boar spermatozoa.

Transcriptional regulation of the insulin-like growth factor-I receptor gene: evidence for protein kinase C-dependent and -independent pathways

An important mechanism whereby growth factors stimulate vascular smooth muscle cell proliferation is by increasing insulin-like growth factor (IGF)-I receptor binding. To characterize the mechanisms involved, we studied transcription of the IGF-I receptor gene in rat aortic smooth muscle cells. Angiotensin II (100 nM) and basic fibroblast growth factor (5 ng/ml) caused a marked increase in IGF-I receptor messenger RNA (mRNA) levels, peaking at 3 h (215 +/- 16.8% and 85 +/- 7.4% above control, respectively). Nuclear run-on assays indicated that angiotensin II and fibroblast growth factor stimulated IGF-I receptor gene transcription by 2.1- and 2.5-fold, respectively. Down-regulation of protein kinase C, a serine/threonine kinase that is important in growth factor-activated signal transduction, completely inhibited fibroblast growth factor- but not angiotensin II-mediated up-regulation of IGF-I receptor mRNA. The protein kinase C inhibitors chelerythrine (3 microns), calphostin C (100 nM), and staurosporine (10 nM) also blocked fibroblast growth factor but not angiotensin II induction of IGF-I receptor mRNA. Thus, angiotensin II and fibroblast growth factor transcriptionally regulate the IGF-I receptor gene by protein kinase C-independent and -dependent pathways, respectively. In view of our prior data indicating that IGF-I receptor density is a critical determinant of vascular smooth muscle cell growth, our findings have particular relevance to understanding mechanisms whereby growth factors regulate vascular proliferation in vivo.

Epiphyseal lengthening operation--an improved technique

An improved method of epiphyseal lengthening operation and subsequent outer fixation are presented on the basis of experience in 30 cases. The operative technique is described in detail, including the different options of separative traction and osteotomy at subtrochanteric, distal part of the upper femur and lower tibial levels. The physiological and histological research concerning this method is discussed. The authors believe that this procedure is better than the other methods.

G-protein and tyrosine kinase receptor cross-talk in rat aortic smooth muscle cells: thrombin- and angiotensin II-induced tyrosine phosphorylation of insulin receptor substrate-1 and insulin-like growth factor 1 receptor

Insulin-like growth factor I is an autocrine/paracrine factor for vascular smooth muscle cells and is required for angiotensin II- and thrombin-induced mitogenesis. The insulin-like growth factor I-triggered signaling pathway involves autophosphorylation of the beta-subunit of its tyrosine kinase receptor and phosphorylation of insulin receptor substrate-1, the latter providing binding sites for proteins with src homology-2 domains. In rat aortic smooth muscle cells we observed that both angiotensin II and thrombin induced rapid tyrosine phosphorylation of insulin receptor substrate-1. Our results also demonstrated that these mitogens rapidly stimulated phosphorylation of the insulin-like growth factor 1 receptor beta-chain. These data demonstrate a novel interaction between the G-protein coupled angiotensin II and thrombin receptors and the tyrosine-kinase insulin-like growth factor I receptor.

Developmental expression and functional characterization of the potassium-channel subunit Kv3.1b in parvalbumin-containing interneurons of the rat hippocampus

The expression of the voltage-gated K(+)-channel subunit Kv3.1b in the developing hippocampus was determined by immunoblot and immunohistochemical techniques. Kv3.1b protein was detected first at postnatal day (P) 8. The Kv3.1b-immunopositive cell number per tissue section reached a maximum at P14 and was maintained through P40. In contrast, the Kv3.1b protein content of isolated membrane vesicles in immunoblots progressively increased through P40, suggesting an increase in Kv3.1b content per cell throughout this time period. Kv3.1b protein was expressed selectively in the somata, proximal dendrites, and axons of cells lying within or near the pyramidal cell layer, consistent with their being GABAergic inhibitory interneurons. Kv3.1b was present in approximately 80% of parvalbumin-positive interneurons. The developmental onset of Kv3.1b and parvalbumin immunoreactivity was identical. In contrast, Kv3.1b was mostly absent from the subset of somatostatin-positive inhibitory interneurons. Electrophysiological recordings were made from stratum pyramidale interneurons in which morphology and Kv3.1b-positive immunoreactivity were confirmed post hoc. Outward currents had voltage-dependent and biophysical properties resembling those of channels formed by Kv3.1b. The current blocked by low concentrations of 4-aminopyridine (4-AP) showed marked inactivation, suggesting that Kv3.1b may coassemble with other members of the Kv3 subfamily. In current-clamp recordings, concentrations of 4-AP that blocked the current through Kv3.1b channels allowed us tentatively to assign a role to Kv3.1b-containing channels in action-potential repolarization. These data demonstrate that Kv3.1b is regulated developmentally in a specific subpopulation of hippocampal interneurons and that channels containing this subunit may be a major determinant in imparting "fast-spiking" characteristics to these and other cells throughout the central nervous system containing the Kv3.1b subunit.

Evidence for expression of vasopressin V2 receptor mRNA in human lung

Studies using fetal sheep, goats, and guinea pigs indicate that vasopressin may play a role in preparing the fetal lung for the transition from a uterine to an air-breathing environment by slowing lung liquid secretion. The mechanism of vasopressin action is believed to occur through V2 receptors with subsequent activation of amiloride-sensitive sodium channels. However, the presence of the V2 receptor in human lung has not yet been documented. In the present study, expression of the vasopressin V2 receptor in fetal and adult human lung was examined using reverse transcription-polymerase chain reaction (RT-PCR), Northern blot analysis, and DNA sequencing. Using RT-PCR and primer pairs specific for the human V2 receptor, PCR products of the predicted sizes of 512 and 862 bp were obtained from adult human lung. DNA sequencing of the cloned PCR products revealed exact identity with the published sequence for the V2 receptor. Northern blot analysis revealed the expression of a approximately 1.9 kb mRNA in adult human lung as well as in kidney, but not in fetal human lung at 22-24 weeks of gestation. However, using the more sensitive RT-PCR assay the 862-bp product was successfully amplified from human fetal lung, although the data indicate the mRNA for this receptor is expressed in lower levels than in adult human lung or kidney. Using RT-PCR and primers specific for the rat V2 receptor, a PCR product of the predicted size of 461 bp was amplified from adult rat lung and kidney, despite an earlier report that this receptor mRNA is absent from the lung of this species. The role for the V2 receptor in adult human lung is unknown at this time, but, as in the human kidney and lungs of fetal sheep, goats, and guinea pigs, this receptor may play a role in fluid balance.

Biomechanical study on unilateral single-plane external fixer

Six tibias removed from 30-40 years old males, who died in an accident for in less than 12 hours, were osteotomized at one-third supra-medium segment. They were fixed by an unilateral adjustable external fixer (UAEF), to be used as a model of external fixation of tibial fracture (MEFTF). The compression, tension, torsion, antero-posterior and lateral bending strength, and the strength for vertically extracting the pins from the tibia were determined in the MEFTF. Within a certain range of load, the correlation of strain to stress was basically a linear relationship. These data provide a theoretical basis of biomechanics for the improvement of UAEF and for early exercises of fracture patients, such as extend-bending of the joint, raising the limb and walking with a walking stick.

A role for cAMP in angiotensin II mediated inhibition of cell growth in AT1A receptor-transfected CHO-K1 cells

G-protein coupled Angiotensin II receptors (AT1A), mediate cellular responses through multiple signal transduction pathways. In AT1A receptor-transfected CHO-K1 cells (T3CHO/AT1A), angiotensin II (AII) stimulated a dose-dependent EC50 = 3.3 nM) increase in cAMP accumulation, which was inhibited by the selective AT1, nonpeptide receptor antagonist EXP3174. Activation of protein kinase C, or increasing intracellular Ca2+ with ATP, the calcium ionophore A23187 or ionomycin failed to stimulate cAMP accumulation. Thus, AII-induced cAMP accumulation was not secondary to activation of a protein kinase C- or ca2+/calmodulin-dependent pathway. Since cAMP has an established role in cellular growth responses, we investigated the effect of the AII-mediated increase in cAMP on cell number and [3H]thymidine incorporation in T3CHOA/AT1A cells. AII (1 microM) significantly inhibited cell number (51% at 96 h) and [3H]thymidine incorporation of 68% at 24 h) compared to vehicle controls. These effects were blocked by EXP3174, confirming that these responses were mediated through the AT1 receptor. Forskolin (10 microM) and the cAMP analog dibutyryl-cAMP (1 mM) also inhibited [3H]thymidine incorporation by 55 and 25% respectively. We extended our investigation on the effect of AII-stimulated increases in cAMP, to determine the role for established growth related signaling events, i.e., mitogen-activated protein kinase activity an tyrosine phosphorylation of cellular proteins. AII-stimulated mitogen-activated protein kinase activity and phosphorylation of the 42 and 44 kD forms. These events were unaffected by forskolin stimulated increases in cAMP, thus the AII-stimulated mitogen-activated protein kinase activity was independent of cAMP in these cells. AII also stimulated tyrosine phosphorylation of a number of cellular proteins in T3CHO/AT1A cells, in particular at 127 kD protein. The phosphorylation of the 127 kD protein was transient, reaching a maximum at 1 min, and returning to basal levels within 10 min. The dephosphorylation of this protein was blocked by a selective inhibitor of cAMP dependent protein kinase A, H89-dihydrochloride and preexposure to forskolin prevented the AII-induced transient tyrosine phosphorylation of the 127 kD protein. These data suggest that cAMP, and therefore protein kinase A can contribute to AII-mediated growth inhibition by stimulating the dephosphorylation of substrates that are tyrosine phosphorylated in response to AII.

Extracellular dopamine in the medial preoptic area: implications for sexual motivation and hormonal control of copulation

Dopamine (DA) activity in the medial preoptic area (MPOA) contributes to the control of male rat sexual behavior. We tested (1) whether extracellular DA increases during precopulatory exposure to an estrous female and during copulation, (2) whether exposure to another male increases extracellular DA, (3) whether motor activity during copulation accounts for increased DA levels, and (4) whether concurrent or recent testosterone influences DA levels or copulation in castrates. Extracellular DA and its metabolites in male rats' MPOA were measured using microdialysis. DA level increased during precopulatory exposure to the female in all animals that subsequently copulated; this included all intact animals, all testosterone-treated castrates, and 9 of 14 1-week castrates treated with oil vehicle. DA levels did not increase in any animal that subsequently failed to copulate, including the remaining 1-week, and all 2-week, vehicle-treated castrates. When the barrier was removed and the animals were allowed to copulate, levels of DA and its metabolites continued to rise in intact males and in castrates that copulated. The DA response to the estrous female could not be attributed to nonsexual social stimuli, since exposure to another male was ineffective. The DA response to copulation could not be attributed primarily to motor activity, since animals running voluntarily in a running wheel did not show significantly increased DA. These and previous data suggest that DA released in the MPOA in response to an estrous female may contribute to sexual motivation and copulatory proficiency. Testosterone may promote copulation in part through permissive actions on dopamine release.

Abnormal polarization of EGF receptors and autocrine stimulation of cyst epithelial growth in human ADPKD

The underlying mechanism of the hyperproliferative response of human autosomal dominant polycystic kidney disease (ADPKD) epithelia was studied. Epidermal growth factor (EGF) protein is highly expressed in ADPKD cyst epithelia in vivo, and primary cultures are hyperesponsive to mitogenic stimulation by EGF in vitro. Doses of > 1 ng/ml EGF were highly mitogenic to ADPKD epithelia. 3H-labeled thymidine proliferation assays showed that cyst fluids and ADPKD epithelial cell-conditioned media also stimulated renal epithelial cell proliferation and contained EGF immunoreactivity (6, 30, and 37 kDa) as detected by Western blots. Radioimmunoassays detected mean levels of 2.87 and 1.4 ng/ml EGF in cyst fluids from early (proliferative) and end-stage ADPKD cysts, respectively. Scatchard analysis of 125I-labeled EGF binding to apical and basolateral membrane showed high-affinity binding to basolateral membranes of normal and ADPKD kidneys but additional unique high-affinity receptor binding to apical membranes of ADPKD but not normal kidneys. Cross-linking analysis and antiphosphotyrosine Western analysis demonstrated functionally active apical EGF receptors at 150-170 kDa. These results suggest mediation of cyst expansion via an autocrine loop involving EGF synthesis and processing by cyst epithelial cells, apical secretion into cyst lumens, and subsequent binding to and phosphorylation of apical membrane EGF receptors. These findings are consistent with a membrane protein polarization defect in ADPKD cyst epithelia.

The effect of collection temperature, cooling rate and warming rate on chilling injury and cryopreservation of mouse spermatozoa

The experiments presented here identify several factors that affect survival (motility) of cryopreserved mouse spermatozoa after freezing and thawing. Among these factors are: (i) the temperature at which spermatozoa are collected, (ii) the cooling rate to 0 degrees C and (iii) the warming rate from -196 degrees C to ambient. When excised epididymides were cooled to near 0 degrees (1-4 degrees C) and spermatozoa collected and mixed with cryoprotectant at that temperature, motilities after subsequent freezing and thawing were 8-10 times higher than when the spermatozoa were collected from the epididymides at 22 degrees C. In addition, the survival rates of spermatozoa warmed at rates ranging from 150 to 2000 degrees C min-1 were about five times higher than those in suspensions warmed at about 7500 degrees C min-1. The combination of a low collection temperature and the lower warming rates resulted in approximately 50% motility relative to unfrozen controls. Motility was reduced to 6-8% when the collection temperature was 22 degrees C, and to approximately 10% when frozen suspensions of spermatozoa collected in the cold were rapidly warmed from -196 degrees C. When spermatozoa collected at 22 degrees C were abruptly cooled to 0 degrees C, 40-80% of the cells suffered an irreversible loss of motility after warming. In contrast, when spermatozoa were cooled to 0 degrees C at 1 degree C min-1 and warmed (either rapidly or slowly), motilities were similar to those of uncooled controls (75-90%).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of bFGF on RCS rat eyes

Basic fibroblast growth factor (bFGF) has been implicated as a factor in retinal differentiation and disease. Recent studies have shown that subretinal or intravitreal injections of bFGF delay the retinal degeneration of the RCS rat but the global nature of this effect has been quantified for few test animals and the mechanism underlying this effect is not understood. In order to determine more accurately the global effects of intravitreal bFGF and to further elucidate the mechanism of bFGF promoted photoreceptor cell saving, we injected one of three bFGF doses into the vitreal cavities of young RCS rats. Using measurements from several eyes, we confirmed that a single intravitreal bFGF injection globally delays the RCS dystrophy. Test eyes contained fewer debris zone macrophages and more inner retinal macrophages than did control eyes at 1 month post injection. As bFGF's saving effect waned, the number of inner retinal macrophages decreased and the number of debris zone macrophages increased toward control levels. Dose-dependent cataract formation occurred in 100% of test eyes. Eyes that received the highest bFGF dose showed increased retinal vascularization at 1, 2 and 3 months post injection. The possible relationships between bFGF promoted photoreceptor survival and our findings are discussed.

Environments of the four tryptophans in the extracellular domain of human tissue factor: comparison of results from absorption and fluorescence difference spectra of tryptophan replacement mutants with the crystal structure of the wild-type protein

The local environments of the four tryptophan residues of the extracellular domain of human tissue factor (sTF) were assessed from difference absorption and fluorescence spectra. The difference spectra were derived by subtracting spectra from single Trp-to-Phe or Trp-to-Tyr replacement mutants from the corresponding spectrum of the wild-type protein. Each of the mutants was capable of enhancing the proteolytic activity of factor VIIa showing that the mutations did not introduce major structural changes, although the mutants were more susceptible to denaturation by guanidinium chloride. The difference spectra indicate that the Trp residues are buried to different extents within the protein matrix. This evaluation was compared with the x-ray crystal structure of sTF. There is excellent agreement between predictions from the difference spectra and the environments of the Trp residues observed in the x-ray crystal structure, demonstrating that difference absorption and particularly fluorescence spectra derived from functional single-Trp replacement mutants can be used to obtain information about the local environments of individual Trp residues in multi-tryptophan proteins.

Regulation of vascular smooth muscle cell insulin-like growth factor I receptors by phosphorothioate oligonucleotides. Effects on cell growth and evidence that sense targeting at the ATG site increases receptor expression

We have recently shown that insulin-like growth factor I (IGF I) is a mediator of angiotensin II-induced mitogenesis in vascular smooth muscle cells (Delafontaine, P., and Lou H. (1993) J. Biol. Chem. 268, 16866-16870). To study the role of the IGF I receptor in vascular smooth muscle cell growth, phosphorothioate oligonucleotides were used to modulate IGF I receptors. An antisense oligonucleotide targeting the ATG site inhibited basal and serum-induced DNA synthesis in vascular smooth muscle cells. Mismatch oligonucleotide had no effect, while surprisingly sense oligonucleotide increased IGF I receptor number and basal and serum-induced DNA synthesis. A 51% reduction in IGF I receptor number following exposure to 5 microM antisense oligonucleotide markedly inhibited angiotensin II-induced mitogenesis. A 70% increase in IGF I receptor number following exposure to 5 microM sense oligonucleotide resulted in a 4-fold increase in basal [3H]thymidine incorporation, and angiotensin II (1-1000 nM) had no additive stimulatory effect. An antisense oligonucleotide targeting a sequence starting at +109 base pairs (relative to ATG) also reduced IGF I receptor number, however, the corresponding sense oligonucleotide was without effect. These findings demonstrate that alterations in vascular smooth muscle cell IGF I receptor density play a critical role in the proliferative response of vascular smooth muscle cells to serum and to angiotensin II. In addition, the surprising observation that an ATG-directed sense oligonucleotide up-regulates IGF I receptors identifies a novel effect of oligonucleotides on gene expression.

Irrigation and traction therapy for open fracture with large-sized full-thickness skin-deficit and severely infected wound

In this paper the results of skeletal traction and irrigation therapy (STIT) used for open fracture complicated with large-sized full-thickness skin-deficit and infection wounds (OFIW) were presented. Fourteen patients of OFIW were treated by the plaster cast and wound dressing (PCWD), and 30 patients of OFIW were treated by STIT. The results indicated that after one week of treatment, the white blood cell count in the STIT group, compared to 17.6 +/- 1.0 x 10(9)/L from before treatment, returned to 8.8 +/- 0.8 x 10(9)/L, and in contrast, the cell count of the PCWD group was about 13.0 +/- 1.4 x 10(9)/L. All of wound exudate culture in the STIT group was negative, and those of 7 cases (7/14) in PCWD group were positive (P < 0.01). The symptoms and signs such as pain, fever and septic exudate on the wound in the STIT group were much milder than those in the PCWD group. There were 5 cases (35.7%) of toxicemia and septicemia, 2 cases (14.3%) of osteomyelitis, 2 cases (14.3%) of amputation, 1 case (7.1%) of delayed union and 3 cases (21.4%) of malunion in the PCWD group, and no complications in the STIT group.

Inhibition of vascular smooth muscle cell growth through antisense transcription of a rat insulin-like growth factor I receptor cDNA

Insulin-like growth factor I (IGF I) is an autocrine/paracrine growth factor that is produced in multiple tissues and is essential for normal developmental growth. Its effects are mediated by activation of a membrane-bound tyrosine kinase receptor, IGF IR. On the basis of the partial rat IGF IR alpha-chain cDNA sequence previously reported, we cloned cDNA encoding the full-length rat IGF IR. The deduced amino acid sequence predicts a 1370-amino acid receptor precursor, which includes signal sequence, a 707-amino acid alpha-chain, a 4-Arg cleavage site, and a 629-amino acid beta-chain. Overall, similarity to human IGF IR is 89% and 98% at the nucleotide and amino acid levels, respectively. Antisense IGF IR expression constructs in vectors incorporating Epstein-Barr virus replicative signals and the cytomegalovirus promoter/enhancer or the inducible human metallothionein IIa promoter/enhancer were assembled and stably transfected into cultured rat aortic smooth muscle cells. Clone CA9 (constitutively expressing abundant antisense IGF IR transcripts), clones MA5 and MA7 (expressing antisense IGF IR transcripts inducibly), and clones ME8 and ME10 (expressing vector alone) were characterized. There was a 57% reduction in IGF IR mRNA levels in clone CA9 after confluence compared with clone ME10. This resulted in a 51% decrease in IGF I binding sites in clone CA9, without a change in binding affinity (Kd), and a 55% and 57% reduction in DNA synthesis rates, basally and in response to 10 ng/mL IGF I, respectively. Clones MA5/MA7 similarly showed a 54% reduction in IGF IR number after confluence following exposure to 100 mumol/L ZnSO4 and a 44% and 58% reduction in DNA synthesis, basally and in response to 10 ng/mL IGF I, respectively. Growth curves indicated that proliferation of clone CA9 in the presence of 10% serum was reduced by 60% compared with clone ME10. Thus, cloning of cDNA encoding the full-length rat IGF IR indicates that this receptor is highly conserved. Antisense targeting of this receptor in vascular smooth muscle cells (VSMCs) demonstrates that a decrease in IGF IR density results in marked inhibition of VSMC proliferation. These findings indicate an important role for this ligand-receptor system in regulating VSMC growth. Specifically, they suggest that modulation of VSMC IGF IR density may be an important mechanism whereby growth of these cells is controlled.

Stable expression of a functional rat angiotensin II (AT1A) receptor in CHO-K1 cells: rapid desensitization by angiotensin II

The octapeptide angiotensin II mediates the physiological actions of the renin-angiotensin system through activation of several angiotensin II receptor subtypes; in particular the AT1. In many tissues, the presence of multiple angiotensin II receptor subtypes, together with a low number of receptors, makes it difficult to study biological responses to physiological concentrations (10(-11)-10(-9) M) of angiotensin II. Also, cultured cells show diminished angiotensin II receptor binding with respect to time in culture and passage number. To address these problems, we expressed the recombinant AT1A receptor in CHO-K1 cells. The stably transfected receptor was characterized using radioligand binding studies and functional coupling to cytosolic free calcium. Radioligand binding of [125I] angiotensin II to the angiotensin II receptor was specific, saturable, reversible and modulated by guanine nucleotides. Like the endogenous AT1A receptor, reported in a variety of tissues, the specific, noncompetitive, nonpeptide AII receptor antagonist, EXP3174, blocked binding of [125I] angiotensin II to the transfected receptor. Scatchard analysis demonstrated that the transfected receptor had a dissociation constant of 1.9 nM with a density of 3.4 pmol/mg protein. An important feature of many of the responses to angiotensin II is the rapid desensitization that occurs following agonist occupancy and the development of tachyphylaxis. In AT1A receptor transfected CHO-K1 cells, angiotensin II (10(-9) M) stimulated a rapid increase in cytosolic free calcium that was completely desensitized within 50 sec following receptor occupancy. Agonist induced desensitization was unaffected when receptor internalization was blocked by pretreatment with concanavalin A or incubation at 4 degrees C, and no changes in AT1A receptor affinity or number were observed. Receptor desensitization was also unaffected by inhibition or activation of protein kinase C. Thus, we have established a permanent, high-level transfectant of the AT1A receptor in CHO-K1 cells and have shown that these receptors rapidly desensitize following exposure to physiological concentrations of agonist. The mechanism of rapid desensitization is not related to receptor sequestration, internalization or controlled by PKC phosphorylation. This provides an excellent model for studying AII actions mediated through a specific receptor subtype, at subnanomolar concentrations.

[Clinical application of heparin--free hemodialysis by hemophan dialyzer]

Heparin-free hemodialysis (HFHD) is important in patient hemodialysis with ARF and CRF with hemorrhagic trend. Adsorption method HFHD was used clinically in patients in our hospital. The method showed that the positively charged hemophan membrane binds the negatively charged anticoagulant heparin. The result showed that adsorption method HFHD has good bioconcomitance, needs no special medicine and equipment, and never increase the load of heart. It is simple and has high successful rate ( > or = 90%).

[Construction and application of the chromosomal specific probe pool from human chromosome no. 7]

We constructed a chromosomal specific probe pool from human chromosome No. 7 using the techniques of chromosomal microdissection, PCR and chromosomal painting. A patient's pedigree with an abnormal chromosome No. 7 were analysed by the above probe pool.

Human spermatozoa glycerol permeability and activation energy determined by electron paramagnetic resonance

The permeability of human spermatozoa to glycerol and its activation energy were determined using electron paramagnetic resonance (EPR) techniques. EPR was used to monitor the aqueous cell volume change vs. time during the glycerol permeation process using the aqueous spin label 15N-tempone and the membrane impermeable broadening agent potassium trioxalatochromiate (chromium oxalate). The permeation process was completed in tens of seconds, requiring the use of a stopped-flow methodology. The glycerol permeability coefficient (Pg) was determined by fitting a simple theoretical model to the experimental data. The permeabilities of human spermatozoa in 1 molar and 2 molar glycerol at 20 degrees C are (10.3 +/- 0.3).10(-4) cm/min (mean +/- S.D.) and (6.0 +/- 1.4).10(-4) cm/min, respectively. The permeabilities of human spermatozoa in 2 molar glycerol at 30, 20, 10, and 0 degrees C are (8.3 +/- 1.3).10(-4) cm/min, (6.0 +/- 1.4).10(-4) cm/min, (2.1 +/- 0.4).10(-4) cm/min, and (1.1 +/- 0.3).10(-4) cm/min, respectively. The activation energy (Ea) for glycerol permeation between 30 degrees C and 0 degrees C was found to be 11.6 kcal/mol.

Case-control study of residential radon and lung cancer in Winnipeg, Manitoba, Canada

A case-control study of lung cancer in relation to exposure to radon in homes in Winnipeg, Manitoba, Canada, was conducted during 1983-1990. In total, 738 individuals with histologically confirmed incident cases of lung cancer were interviewed, along with 738 controls matched on age (+/- 5 years) and sex. Radon dosimeters were placed in all residences in which the study subjects had reported living within the Winnipeg metropolitan area for at least 1 year. Radon dosimetry was done by means of integrated alpha-track measurements over a 1-year period. In the homes monitored, the average level of radon-222 was about 120 becquerels (Bq)/m3 in the bedroom area and 200 Bq/m3 in the basement. After adjusting for cigarette smoking and education, no increase in the relative risk for any of the histologic types of lung cancer observed among the cases was detected in relation to cumulative exposure to radon.

Indomethacin inhibition of hog gastric H+/K(+)-ATPase arises from its effect on both the enzyme protein and the lipid bilayer

Indomethacin showed a dose-, time-, and pH-dependent, noncompetitive inhibitory effect on hog gastric H+/K(+)-ATPase. Four percent of total indomethacin in the buffer (0.20 mmol/liter) bound to the H+/K(+)-ATPase vesicles (15 micrograms/ml). It markedly quenched the intrinsic fluorescence of the enzyme, and decreased the membrane fluidity. Thus, the inhibitor effect of indomethacin may arise from both a direct effect on the hydrolytic and H+ transport functions of the enzyme and a disturbing effect on the lipid bilayer of the vesicle.

Long-term photoreceptor transplants in dystrophic and normal mouse retina

PURPOSE

To determine the long-term status of transgenic photoreceptors transplanted to the subretinal space of both rd mutant (receptorless) and normal mouse retina.

METHODS

Microaggregates of neural retina from transgenic mice containing lacZ-labeled photoreceptors were transplanted to the subretinal space of adult rd mutant and normal mice. The transplant site was examined by light and electron microscopy at monthly intervals up to 9 months after transplantation surgery.

RESULTS

Photoreceptors develop and survive well if transplanted with the proper orientation to the retinal pigment epithelium (RPE). The status of the photoreceptors, including outer segments and synaptic terminals, appear normal for at least 9 months after transplantation; they continue to express the lacZ reporter gene. Cones survive as well as rods. Transplants to the normal mouse develop normally, whereas the host photoreceptors displaced from the RPE degenerate. A barrier, formed by Müller cell processes, develops after photoreceptor degeneration in both normal and rd mouse retina and demarcates host from transplant tissue. Areas can be found in which neural processes have penetrated this barrier. There is no evidence of host-graft rejection.

CONCLUSION

Transplanted progenitor photoreceptors develop and survive well for long periods of time in either the rd mutant or normal retina if they are properly positioned. In the former, they reconstitute a photoreceptor layer; in the latter, they replace the host photoreceptor layer, which degenerates after being displaced from the RPE. Areas of potential contact between donor and host neurons exist in these transplants.