A new nortriterpenoid saponin from the roots of Symplocos caudata Wall

A new nortriterpenoid saponin, 3β,17β-dihydroxy-28-nor-12-oleanen-16-one 3-O-β-d-galactopyranosyl (1 → 2)-{α-l-arabinopyranosyl (1 → 3)-[α-l-arabinofuranosyl (1 → 4)-β-d-glucuronopyranoside]} (1), along with two pairs of known isomers, was isolated from the roots of Symplocos caudata Wall. Their structures were elucidated by spectroscopic and chemical methods.

Clinical characteristics and prognosis of diffuse proliferative lupus nephritis with thrombotic microangiopathy

We retrospectively analyzed the clinicopathologic characteristics and prognosis of 33 patients with diffuse proliferative lupus nephritis (class IV LN) complicated with thrombotic microangiopathy (TMA). Eighty-one percent of patients had renal dysfunction (mean Scr 3.1 ± 2.0 mg/dl), among whom 42.4% needed acute hemodialysis. Nephrotic proteinuria, gross hematuria and hypertension were presented in 57.6%, 24.2% and 93.9% of the patients. Microangiopathic hemolytic anemia, serum anti-dsDNA and anticardiolipin antibodies were found in 60.6%, 75.8% and 33.3% of the patients. Renal biopsy showed IV-G in 75.8%, class IV with class V in 21.2%, and IV-S in 1.23% of the patients. Glomerular segmental necrosis, microthrombi, crescents and arteriolar thrombosis were found in 51.5%, 69.7%, 60.6% and 60.7% of the patients, respectively. The follow up was 1 to 101 months (median 13 months). Only 50% of patients showed response to treatment. Three patients died, 10 developed end-stage renal failure (ESRF). The 5-year patient and renal survival rate was 69.2% and 46.7%, respectively. Major risks for ESRF included: a need for acute dialysis on admission, no response to the treatment and high renal chronic index. The results showed that class IV lupus nephritis with TMA has high mortality and low renal survival.

SNP detection and haplotype analysis in partial sequence of MSTN gene in sheep

Polymerase chain reaction (PCR) products of the MSTN gene amplified from sixty sheep of nine Chinese indigenous sheep breeds and one imported sheep breed were sequenced to identify the single-nucleotide polymorphisms (SNPs) in a 378-bp fragment including intron 2 and exon 3 of the MSTN gene. A total of fifteen SNPs (A1937C, T1942G, C1956T, A1972C, A1990G, A2008C, A2011G, C2019T, A2025C, A2027C, T2085G, T2173C, C2198T, C2210T and C2213T) were detected among the sixty sequenced individuals and they were all located in intron 2. Twelve haplotypes were identified from these fifteen SNPs, of which haplotype I (CGTCGCGTCCGCTTT) and VIII (ATCAAAACAATTCCC) were the two major and basic ones with frequencies of 12.25% and 77.80%, respectively. Haplotype VIII was distributed in all sheep breeds and all individuals of the meat or meat-wool type sheep breeds were homozygous with respect to this haplotype. This suggests that haplotype VIII might be related to meat production traits in sheep. Haplotype I was only distributed in the fur, lambskin type and fur-meat type sheep breeds. This suggests that haplotype I may have some relationship with fur traits in sheep.

Polycyclic aromatic hydrocarbon (PAHs) pollutants in groundwater from coal gangue stack area: characteristics and origin

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the leachate from the gangue and 20 groundwater samples, which were collected from the 12th Coal Mine around gangue piles in Henan Province, China, were determined by SPE-GC-MS. The characteristics of PAHs pollutants in groundwater were investigated, and compared with the concentrations of PAHs in the leachate from different weathered gangues to discuss the pollution effects of PAHs from coal gangue on groundwater. The results showed that total concentrations of the 16 EPA preferentially controlled PAHs ranged from 146.9 ng/L to 1220.6 ng/L.The components of PAHs such as chrysene, benzo[a]anthracene, benzo[b + k]fluoranthene, indeno[1,2,3-c,d]-pyrene, and dibenz[a,h]anthracene were fairly high. The 2-4 rings PAHs such as naphthalene, phenanthrene, fluorene and chrysene were dominant in groundwater, which was similar to those of the leachate from the different weathered gangues. Therefore, it should be paid much more attention on the transport of lower ring numbered PAHs leached by rains from the coal mines after landfilling and dumping. Based on the spatial distribution of PAHs and the high concentrations of PAHs with 2-4 rings in groundwater and leaching samples, there might be other pollution sources of PAHs except for penetration from coal gangue into groundwater in the Pingdingshan coal mine area.

Association of beta-adrenoceptor single nucleotide polymorphisms with resting heart rate

The association of beta-adrenoceptor (B-AR, including three subgroups: Beta1, Beta2 and Beta3) single nucleotide polymorphisms (SNP) with resting heart rate (RHR) were analyzed. RHR of 107 healthy subjects in the supine were detected by computerized system for 8 minutes. Genotyping SNPs of S/G49 and R/G389 of Beta1-AR and W/R64 of Beta3-AR in these subjects were by means of PCR-restriction fragment length polymorphism (PCR-RFLP) technique. Genotyping SNPs of R/G16 and Q/E27 of Beta1-adrenoceptor in these subjects were by means of allele specific primer-PCR (ASP-PCR) technique. It was found that there was no significant difference among RHRs corresponding above SNPs of B-AR, but the SNP of R/G389 of Beta1-AR, in which there was significant difference among RHRs (P<0.05). Either in the female individuals or in the male, those with Beta1-AR G/G389 genotype had the highest RHR. The females with R/R389 genotype had the lowest RHR, however, the males with R/G389 genotype had the lowest RHR. The RHR was not only associated with R/G389 polymorphism of Beta1-adrenoceptor gene significantly, but also was associated with gender in Chinese.

Deficiency of Growth Hormone Receptor Does Not Affect Male Reproduction in Dwarf Chickens

Sex-linked dwarf chickens caused by the mutation of the growth hormone receptor gene are characterized by normal growth hormone (GH), very low insulin-like growth factor I (IGF-I) level in the blood, and reduced growth. It has been demonstrated that the sex-linked dwarfing gene has negative effects on female reproduction. In the current study, dwarf cocks and their phenotypic normal siblings were used to investigate the effects of dwarf gene on male reproduction. Dwarf cocks grew slower than the normal cocks did, and at 20 wk of age, their BW were 36.4% smaller. However, all parameters for semen quality, including volume, sperm concentration, viability, mobility, pH, and percentage of abnormal sperms, examined at 30 wk of age showed no significant difference between normal and dwarf cocks. The fertility of dwarf cocks was 95.2%, and the normal was 92.4%. The concentrations of GH and IGF-I in serum and seminal plasma were measured with RIA and ELISA, respectively. The serum GH in the dwarf cocks was significantly higher than their normal siblings (P < 0.05), whereas the serum IGF-I in the dwarf cocks was very low. However, the concentration of seminal IGF-I in dwarf cocks was similar to that of their normal siblings, indicating that IGF-I might be produced and acted independently in testis. In conclusion, the deficiency in GH receptor did not affect the male reproduction in dwarf chickens, and the fertility of dwarf cocks could be satisfactory for production when artificial insemination was adopted.

Single-nucleotide polymorphism identification in the caprine myostatin gene

Polymerase chain reaction (PCR) products of MSTN gene amplified from 35 goats representing 17 Chinese indigenous goat breeds and five imported goat breeds were sequenced to identify the single-nucleotide polymorphisms (SNPs) of a 379-bp fragment including part of intron 2 and exon 3 of MSTN gene. A total of eight SNPs (A1980G, G1981C, A1982G, G1984T, A2121G, T2124C, G2174A and A2246G) were identified among the sequenced goats. The SNPs found are all located in intron 2 except for A2246G, which was a synonymous mutation in exon 3. Four haplotypes were sorted from these eight SNPs, of which, haplotype I (AGAGATGA) and haplotype II (GCGTGTAA) are the two main haplotypes with the frequency of 77.8% and 14.8% respectively. The SNPs found at positions 1980, 1981, 1982, 1984 and 2121 might be linked to inheritance completely.

A study on eggshell pigmentation: biliverdin in blue-shelled chickens

Biliverdin is an important pigment in the eggshell of chickens and other avian species. Determination of the biosynthesis site for biliverdin is essential for understanding the biochemical process and genetic basis of eggshell pigmentation. Either blood or the shell gland could be the biosynthesis site of eggshell biliverdin. A segregation population with full-sib sisters genotyped Oo and oo, which laid blue-shelled eggs and light brown eggs, respectively, was constructed in a native Chinese chicken breed. Ultraviolet spectrophotometry and HPLC were used to determine the biliverdin concentration in eggshells, blood, bile, excreta, and shell gland of both groups of chickens. Biliverdin content was significantly different between egg shells of blue-shelled and brown-shelled chickens (P < 0.01). Blood and bile were tested 3 to 4 h before oviposition, and excreta was tested randomly. Results showed no significant difference in biliverdin concentration in blood, bile, and excreta between the 2 groups. In the shell gland, the biliverdin contents for the blue-shelled and brown-shelled chickens were 8.25 +/- 2.55 and 1.29 +/- 0.12 nmol/g, respectively, which showed a significant difference (P < 0.01). Our results demonstrated that blood is not the biosynthesis site of the shell biliverdin. Biliverdin is most likely synthesized in the shell gland and then deposited onto the eggshell of chickens.

Post-treatment of banknote printing works wastewater ultrafiltration concentrate

A novel process of vortex settling and stage-2 ultrafiltration (UF) with alternating feed direction was used to further concentrate the concentrate produced by a stage-1 UF employed for treatment of banknote printing works wastewater. In this post-treatment process, the final concentrate volume for incineration was reduced by 4-5 times while the permeate of the stage-2 UF could be further reused in the banknote printing operation. It was noted vortex settling facilitated settling of the printing ink and the strategy of regularly alternating feed direction in the UF resulted in a higher permeate flux compared to the corresponding flux for operation without alternating feed direction. The hydraulic retention time (HRT) of the vortex settling tank (VST) used in the pilot-scale experiment was 14 min while feed direction to the stage-2 UF was alternated once every hour. Based on the pilot-scale experimental results, a full-scale system was set up. An economic analysis showed that the novel system was a cost-effective option for post-treatment of stage-1 UF concentrate. The treatment system has been successfully implemented at several Chinese banknote printing companies.

Exact representation of crossover of transitions from first order to second order in the Potts model for rumor transmission

The L-state Potts model for rumor is the N-spin chain describing how a simple rumor transmitted by N recreant rumormongers is aggrandized. The studied rumor is represented mathematically by a simple proposition with the universal quantifier, which again is represented geometrically by a point in a proposition space. During the transmission, such a proposition is changed with the change of the rumor, which has individual number N0 at the beginning of the transmission. Correspondingly, the point expressing the proposition may start from an arbitrary site at the proposition space, and then it shifts in the space. Thus, a spin sum of the Potts model corresponds to a walk of a point in the proposition space and spin configuration's numbers is given by enumerating the corresponding walks. The concept of the lattice path in combinatorial mathematics is introduced and the exact series representation of the configuration's numbers is given. The partition function exhibits the transition of the chain and critical equivalent inverse temperature beta(c) is determined. Moreover, there is a crossover value of the individual number, N00. The model has a first-order transition when N0<N00 and a second-order one when N0>N00.

Density waves in traffic flow of two kinds of vehicles

Through the car-following model, the traffic flow of two types of vehicles (cars and trucks) on a single-lane flow is studied, in which drivers on different vehicles have different sensitivities and the safety distance is assumed to be the same for all vehicles. The linear analysis is carried out to determine the condition of critical stability. With the nonlinear analysis, it proves that the small fluctuation of the vehicle density near the critical stable state satisfies the Korteweg-deVries equation and different sensitivities affect only the soliton evolution. When the headway in the critical state is more than the safety distance, the density around the soliton peak exceeds the density of the critical stable state, which can be explained as the formation of traffic jam. Contrarily, when the headway state is less than the safety distance, drivers will increase the headway to avoid the jam. The direct approach of the soliton perturbation shows that drivers' sensitivity will increase the soliton's amplitude continuously. Moreover, the increase of the number of trucks in the traffic flow will slow down the evolution of the amplitude.

A new synthetic method for preparing indole derivatives from 2-keto glycosides

In this article, a new reaction of the addition of two molecules of aniline to 2-keto glycosides (glycoside 2-uloses, 2-ulosides) is reported. A possible pathway for the reaction is presented. This reaction provides a novel one-pot method for the synthesis of indole derivatives from sugars.

Effects of corticotrophin on pain behavior and BDNF, CRF levels in frontal cortex of rats suffering from chronic pain

AIM

To investigate the effects of corticotrophin (Cor) on corticotropin-releasing factor (CRF), brain-derived neurotrophic factor (BDNF), and its functional receptor trkB in the frontal cortex of complete Freud's adjuvant (CFA)-induced arthritic rats.

METHODS

The chronic pain rat model was modified and pain behaviour scores were assessed. BDNF-immunoreactivity (IR), trkB-IR, and CRF mRNA-positive neurons were measured by immunohistochemistry and in situ hybridization methods.

RESULTS

Compared with control rats, pain behavior scores, BDNF-IR, CRF mRNA-positive, trkB-IR, and BDNF/CRF mRNA double-labeling neurons in the contralateral frontal cortex of the arthritic rats increased significantly at 24 h after injection of CFA (P < 0.05), and these effects were decreased markedly by i.p. injection of Cor (P < 0.05). The decrease in pain behavior and BDNF-IR, CRF mRNA levels in frontal cortex of arthritic rats due to Cor were partly prevented by adrenalectomy (ADX).

CONCLUSION

The increment in BDNF and CRF levels in the contralateral frontal cortex of arthritic rats may be inhibited by corticotrophin.

Ratio of canonical and microcanonical temperatures of a vibratory antiferromagnetic ising chain

The ratio of canonical and microcanonical temperatures T(c)/T(&mgr;) of a vibratory antiferromagnetic Ising chain with N spins is given by analytical calculation. The result is T(c)/T(&mgr;)=1+O(N-1), which is consistent with the natural assumption given by Rugh.

[Immunohistochemical study of oral mucosa precancerous lesion and expression of cytokeratin of squamous cell carcinoma]

OBJECTIVE:The aim of this study was to investigate the expression and distribution of cytokeratin in oral mucosa. METHODS: Polyclonal cytokeratin antibody A(575) and ABC immunohistochemical technique were used. RESULTS: A tendency of progressive increase of cytokeratin expression was demonstrated from normal mucosa,mild moderate and severe dysplasia to squamous cell carcinoma. A notable overexpression was found in moderate,severe dysplasia and squamous cell carcinoma.The poor-differentiatin was related to the low reaction of A(575).The cases of strong reaction of A(575)were more advanced stages and metastasized to lymph nodes frquently. CONCLUSION: The overexpression of cytokeratin could play a role in potentiation the effects of genetic factors and activate oncogenes in the affected cells.The cumulative effects of the potentiation would be accelerate the progression of precancerous conditions.The reaction of A(575) was correlated with clinical stages and lymph node metastasis.

Chemistry of loteprednol etabonate and related steroids. II. Reactions at ring C and NMR structural studies of the resulting compounds

Several derivatives of lotoprednol etabonate (1), a soft corticosteroid antiinflammatory drug, are formed during the synthesis and sterilization process. Some of these contaminants of 1 result from side reactions taking place on the steroid ring C including oxidation, dehydration, chlorination and chlorohydroxylation. The products have been identified, synthesized, and fully characterized by 1H and 13C NMR spectroscopy.

Critical role of TrkB and brain-derived neurotrophic factor in the differentiation and survival of retinal pigment epithelium

In the vertebrate eye, the retinal pigment epithelium (RPE) and the neural retina arise from a single layer of neuroectoderm. Factors influencing the differentiation of retinal neurons have been identified; however, little is known about molecules directing the differentiation of the RPE. Here we have found that the neurotrophin brain-derived neurotrophic factor (BDNF) plays an autocrine role in the differentiation and survival of Xenopus laevis RPE. Fluorescent in situ hybridization studies showed a precise co-expression of BDNF and its receptor trkB in the retinal neuroepithelium and actively differentiating RPE; in vitro studies demonstrated survival- and differentiation-promoting effects in serum-free explants and dissociated cultures. When a dominant negative mutant of the trkB receptor was expressed in developing embryos, severe arrest of RPE differentiation was seen with persistence of nestin- and Notch-positive neuroblasts.

Developmental regulation and the role of insulin and insulin receptor in metanephrogenesis

The insulin family of peptides and their receptors influence cellular growth in very early preimplantation embryos. In this study their expression and role in renal organogenesis was investigated. By immunofluorescence microscopy and in situ hybridization, insulin receptor (IR) expression was seen in the ureteric bud branches and early nephron precursors in mouse metanephroi harvested at day 13 of gestation. The expression gradually decreased in successive stages of gestation, and it was confined mainly to renal tubules in 1-week-old mice. Similar developmental regulation of the IR and insulin was observed by reverse transcriptase-polymerase chain reaction (RT-PCR) analyses. Addition of insulin into the culture medium at low concentrations, ranging from 40 to 400 ng/ml, induced trophic changes and increased [3H]thymidine incorporation in the embryonic renal explants, and inclusion of IR beta-subunit-specific antisense oligodeoxynucleotide caused marked dysmorphogenesis and growth retardation of the metanephroi. Specificity of the antisense effect was reflected by immunoprecipitation experiments in which translational blockade of the beta subunit of the IR was observed. RT-PCR analyses revealed that the alpha subunit of the IR was unaffected by the antisense treatment of metanephric explants. Concomitantly, de novo synthesis of morphogenetic regulatory extracellular matrix proteins, especially the proteoglycans, was decreased. Gel-shift analyses indicated a failure in the activation of c-fos promoter region binding protein(s) by insulin in the antisense oligodeoxynucleotide-treated explants. These studies suggest that insulin and its putative receptor are developmentally regulated in the murine embryonic metanephros, and they play a role in renal organogenesis, possibly by affecting other modulators of morphogenesis-i.e., extracellular matrix proteins and protooncogenes.

Influence of glucose on murine metanephric development and proteoglycans: morphologic and biochemical studies

The offspring of severe juvenile diabetics suffer from a multitude of congenital anomalies, including genito-urinary defects. Whether these defects are related to hyperglycemic states remains to be determined. In this study, the effect of glucose on metanephric development and extracellular matrix proteoglycans (PG), the regulators of morphogenesis, was investigated. Metanephric explants, harvested at Day 13 of gestation, were exposed to 30 mM of D-glucose for 1 to 7 days in an organ culture system. Light microscopy revealed a significant reduction in the size of explants and the nephron population in metanephroi exposed to glucose. A marked dysmorphogenesis of the ureteric bud branches was also observed. They were swollen and had blunted tips. The latter are the site of nascent nephron formation. Electron microscopy revealed malformation of the S-shaped body nephrons, which had poorly formed clefts and lacked cells in their distal convolutions. The precapillary stage glomeruli showed effacement of the foot processes, attenuation of the glomerular basement membrane, decreased surface microvilli, and an increased number of intercellular junctions. Immunofluorescence microscopy indicated a decreased reactivity of antibody directed against basement membrane heparan sulfate-PG. By light microscopy-autoradiography, a generalized decrease in [35S] sulfate incorporation was observed, especially at the tips of the ureteric bud branches. Electron microscopy-autoradiography revealed a significant decrease in the silver grain density (concentration of radiation) in the matrix compartment of the nephrons, i.e., cleft of the S-shaped body and glomerular basement membrane of the precapillary-stage glomeruli. Biochemical studies revealed a decrease in the incorporated radioactivity associated with the fraction of PG. The newly synthesized PG had a reduction in their molecular weight and charge-density characteristics but had an increased proportion of chondroitin sulfate. These data suggest that D-glucose induces marked dysmorphogenesis of the embryonic kidney during in vitro metanephric development and that these alterations may be related to perturbations in the de novo synthesis of PG, one of the essential morphogenetic regulators of the extracellular matrix.

D-glucose-induced dysmorphogenesis of embryonic kidney

An organ culture system was used to study the effect of D-glucose on embryonic kidneys, and to delineate the mechanism(s) relevant to their dysmorphogenesis. Metanephroi were cultured in the presence of 30 mM D-glucose. A notable reduction in the size and population of nephrons was observed. Ureteric bud branches were rudimentary and the acuteness of their tips, the site of nascent nephron formation, was lost. Metanephric mesenchyme was atrophic, had reduced cell replication, and contained numerous apoptotic cells. Competitive reverse transcriptase-PCR analyses and immunoprecipitation studies indicated a decrease in expression of heparan sulfate proteoglycan (perlecan). Status of activated protein-2 was evaluated since its binding motifs are present in the promoter region of the perlecan gene. Decreased binding activity of activated protein-2, related to its phosphorylation, was observed. D-glucose-treated explants also had reduced levels of cellular ATP. Exogenous administration of ATP restored the altered metanephric morphology and reduced [35S]sulfate-incorporated radioactivity associated with perlecan. The data suggest that D-glucose adversely affects the metanephrogenesis by perturbing various cellular phosphorylation events involved in the transcriptional and translational regulation of perlecan. Since perlecan modulates epithelial/mesenchymal interactions, its deficiency may have led to the metanephric dysmorphogenesis and consequential atrophy of the mesenchyme exhibiting accelerated apoptosis.

Effects of hepatocellular mitogens on cytokine-induced nitric oxide synthesis in human hepatocytes

The synthesis of induced nitric oxide (NO) is regulated by several cytokines, including growth factors produced following hepatic injury and inflammation. However, little information is available on the role of growth factors in regulating the inducible NO synthase in human hepatocytes. The capacity of hepatocellular mitogens (HGF, EGF, and TGF-alpha) to regulate the inducible NO synthase (iNOS) was studied in human hepatocytes incubated with inflammatory cytokines and lipopolysaccharide (LPS). Furthermore, the effects of hepatic mitogens on NO-induced changes in DNA and protein synthesis was studied. It was found that NO-mediated decrease of protein and DNA synthesis were partially reversed by the mitogens. This was associated with a down-regulation in cytokine-mediated hepatocyte NO formation, iNOS mRNA expression, and NOS enzyme activity. Cytokine-induced NO formation or SNAP, an NO donor, added with cytokines increased hepatocyte chromatin condensation but no DNA fragmentation was observed. The increase in chromatin condensation was partially reversed by hepatic mitogens and corresponded with the inhibition of NO production. Thus, the hepatic mitogens, HGF, EGF, and TGF-alpha, all suppress iNOS expression and it is the suppression of iNOS that appears to be responsible for the mitogen-reduced preservation of DNA and protein synthesis and prevention of chromatin condensation.

Comparative role of phosphotyrosine kinase domains of c-ros and c-ret protooncogenes in metanephric development with respect to growth factors and matrix morphogens

Receptor-like protooncogenes, with tyrosine kinase catalytic domains, are expressed in neoplastic and fetal tissues and potentially have a role in embryonic development. Which protooncogene may have the dominant role in embryonic renal development during the "postinductive" period, i.e., Day 10 onward, was addressed in this study by utilizing an in vitro organ culture system. The role of various receptor-like protooncogenes, with the emphasis on c-ros and c-ret, was investigated by antisense-oligodeoxynucleotide (ODN) gene-targeting strategies at a point in metanephric development when reciprocal-inductive interactions between the epithelium and mesenchyme have already been initiated and are rampant. Also, their relationship with other morphogens, like extracellular matrix (ECM) proteins and growth factors, was studied. Initial in situ hybridization and RT-PCR analyses revealed a similar spatiotemporal expression for both c-ros and c-ret in the embryonic kidneys. At Day 13, they were mainly expressed in the developing nephrons in the nephrogenic zone and ureteric bud branches, where the signals from the mesenchymal ligands are transduced to the epithelial cell surface receptors. Minimal expression was observed in the newborn kidneys. Inclusion of antisense ODNs, derived from the phosphotyrosine kinase domains, inhibited metanephric growth in the organ culture; the most dramatic effects were observed with the c-ret antisense ODN. The c-ret-induced dysmorphogenetic effects were characterized as a decrease in the population of nephrons, atrophy of the mesenchymal cells, and loss of acuteness of the tips of ureteric bud branches. Interestingly, the ureteric bud branches continue to grow in the atrophic mesenchyme. Both c-ros and c-ret antisense ODNs reduced the gene expression and biosynthesis of various ECM proteins. The proteoglycans, expressed at the epithelial:mesenchymal interface, were most adversely affected, especially by the c-ret antisense. The treatment of metanephric explants with c-ret did not affect the gene expression of c-ros and vice versa. The specificity of the effects of c-ret antisense was also reflected by a decrease of anti-Ret protein immunoreactivity. The studies were extended to establish a relationship between c-ret protooncogene and some of the growth factors which are known to influence renal development via their tyrosine kinase-like receptors localized in the ureteric bud branches, the site apparently where c-ret is also expressed. Among the various growth factors examined, transforming growth factor-alpha (TGF-alpha) and insulin like growth factor-I (IGF-I) had the most notable trophic effects on metanephric explants and caused maximal phosphorylation of Ret protein. In addition, concurrent exposure of TGF-alpha or IGF-I and c-ret antisense ODN explants caused partial recovery from the c-ret-induced dysmorphogenetic effects in the metanephroi. The data suggest that, although a number of protooncogenes share similar catalytic domains, c-ret plays a major role during the "postinductive" period of metanephric development by perturbing the growth factor-dependent expression of ECM morphogenetic macromolecules, notably that of the proteoglycans, and also by affecting certain yet undefined growth factor-mediated phosphorylation mechanism(s) involving c-ret.

A cohort of supporting metabolic enzymes is coinduced with nitric oxide synthase in human tumor cell lines

Although nitric oxide (NO) has cytotoxic activity against certain tumor cell lines, some human tumor cell lines can themselves produce NO by expressing the inducible isoform of NO synthase (iNOS). As rates of cellular NO synthesis play a major role in determining whether NO has cytotoxic or cytoprotective effects at anatomic sites of NO production, identification of cellular processes which regulate rates of NO synthesis by iNOS is important for understanding the role of NO in tumor cell biology. This study demonstrates that argininosuccinate synthetase and GTP-cyclohydrolase-I, which catalyze rate-limiting steps in the synthesis of iNOS substrate (arginine) and cofactor (tetrahydrobiopterin), respectively, are coinduced with iNOS expression in two human tumor cell lines. These results indicate that coinduction of these supporting metabolic pathways helps to maximize cellular NO synthesis by iNOS in human tumor cells, suggesting that these pathways might be useful targets for pharmacologic intervention in NO-producing human tumor cells.

Derivatives of Dexanabinol. I. Water-soluble salts of glycinate esters

PURPOSE

Glycinate ester-type water soluble derivatives of dexanabinol (HU-211) (1) a non-psychotropic cannabinoid with potential use in the treatment of brain damage were synthesized and evaluated as prodrugs or congeners.

METHODS

Conventional procedures were used for the synthesis of the novel derivatives. Stability studies in water and blood (rat, dog, human) were performed by HPLC; NMDA receptor binding was determined by radio ligand [3H] MK-801-displacement; the neuroprotection and neurotoxicity studies were performed in cortical cell cultures.

RESULTS

Glycinate (3), dimethyl- and diethylamine (5, 6), trimethyl- and triethyl- ammonium (7, 8) acetates of 1 were synthesized. All compounds were relatively soluble and stable in water. The quaternary ammonium salt-type derivatives rapidly hydrolyzed to the parent drug in various types of blood including human. In vitro activity studies indicated that the novel derivatives possess NMDA receptor binding properties. The neuroprotecting properties manifested by some of the new derivatives were associated with very low neuronal cell toxicity and are credited to parent compound released by hydrolysis during the experiments rather than to intrinsic activity.

CONCLUSIONS

Compounds 7 and 8 are promising water-soluble pro-drug candidates for 1; the glycinate ester 3 might be used as an active analog.