Induction of Jak/STAT signaling by activation of the type 1 TNF receptor

Cellular responses to TNF are initiated by either of two cell surface receptors, the type 1 TNF receptor (TNFR1) and the type 2 TNF receptor (TNFR2). Although neither receptor contains an intrinsic protein tyrosine kinase, such activity has been implicated in TNF action. In this study, we show that murine TNF induces the tyrosine phosphorylation and activation of the intracellular Janus tyrosine kinases Jak1, Jak2, and Tyk2 in murine 3T3-L1 adipocytes. Activation of Jak kinases by TNF was associated with tyrosine phosphorylation of STAT1, STAT3, STAT5, and STAT6, but not STAT2 or STAT4, showing that TNF acts on a specific subset of these latent cytoplasmic transcription factors in 3T3-L1 adipocytes. Agonist antiserum to TNFR1 induced Jak kinase and STAT protein phosphorylation. Phosphorylation of Jak proteins was also induced by human TNF, which selectively binds to TNFR1 on murine cells. 35S-labeled Jak kinases were precipitated from a cell-free system and from lysates of 3T3-L1 adipocytes by a glutathione S-transferase fusion protein containing the cytoplasmic domain of TNFR1. These results suggest that the cytoplasmic domain of TNFR1 can directly interact with and form signaling complexes with Jak kinases. Jak2 was precipitated from HeLa cells by antiserum to TNFR1, directly demonstrating their association in vivo. Thus, TNF activates a Jak/STAT signal-transduction cascade by acting through TNFR1.

[Effect of adrenomedullin on bronchoconstriction responses induced by histamine]

OBJECTIVE

To observe the effect of synthetic human adrenomedullin (AM) on anesthetized guinea pigs bronchoconstriction induced by histamine.

METHOD

The guinea pigs were divided into saline group; isoproterenol groups at the dosages of 0.03 microgram/kg, 0.3 microgram/kg, 3 micrograms/kg and 30 micrograms/kg; adrenomedullin groups at the dosages of 0.02 microgram/kg, 0.2 microgram/kg, 2 micrograms/kg and 20 micrograms/kg. There were seven guinea pigs a group. Guinea pigs were anesthetized by sodium pentobarbital, normal saline group, isoproterenol and adrenomedullin at different dose i.v., while histamine (10(-4) mol/L) were vasolated and delivered into the airway. Body plethysmogroph was used to measure airway resistance and lung compliance.

RESULT

The increment of airway resistance and decrement of lung compliance induced by histamine were inhibited significantly by isoproterenol at the dosages of 0.3 microgram/kg, 3 micrograms/kg and 30 micrograms/kg (P < 0.05). The increase of airway resistance was inhibited significantly by adrenomedullin at the dosages of 2 micrograms/kg and 20 micrograms/kg (P < 0.05). The decrease of lung compliance induced by histamine was inhibited significantly by adrenomedullin at 0.2 microgram/kg, 2 micrograms/kg and 20 micrograms/kg (P < 0.05).

CONCLUSION

Adrenomedullin inhibited the bronchoconstriction induced by histamine significantly.

Cloning of the Bacillus firmus OF4 cls gene and characterization of its gene product

The gene that codes for cardiolipin (CL) synthase and an adjacent gene that codes for a MecA homolog in the alkaliphilic bacteria Bacillus firmus OF4 have been cloned and sequenced (GenBank accession number U88888). The cls gene contains 1509 nucleotides, corresponding to a polypeptide of 57.9 kDa. The predicted amino acid sequence has 129 identities and 100 similarities with the Escherichia coli CL synthase. Homologies were also noted with polypeptide sequences from putative cls genes from Bacillus subtilis and Pseudomonas putida. Conserved histidine, tyrosine, and serine residues may be part of the active site and participate in phosphatidyl group transfer. The B. firmus OF4 cls gene product was inserted into plasmid pET3 to form a recombinant plasmid pDG2, which overproduces CL synthase in E. coli. A membrane fraction containing the overproduced enzyme converts phosphatidylglycerol to CL and glycerol. The B. firmus enzyme is stimulated by potassium phosphate, inhibited by CL and phosphatidate, and has a slightly higher pH optimum than the E. coli enzyme.

[Determination of salidroside in eight Rhodiola species by TLC-UV spectrometry]

Quantitative determination of the salidroside in eight Rhodiola species by TLC-UV spectrometry is reported. The salidroside was separated on a silica GF254 TLC plate using CHCl3-CH3OH-H2O(26:14:3) as developing solvent and determined at wavelength 223.8 nm. The results show that this method in simple and convenient.

[Electroacupuncture along meridians activating subcutaneous primary afferents in acupoints--CB-HRP tracing study]

The experiment was performed to observe the segmental distribution of sensory afferent nerves in acupoints and the influence of electroacupuncture (EA) along meridians on it. 1% CB-HRP solution (5 microliters) was injected subcutaneously at unilateral "Zusanli" or "Ruzhong" acupoint of rats. The HRP labeled cells were counted in the related spinal dorsal root ganglia (DRG). The results were as follows: the sensory nerve terminals of "Zusanli" acupoint mainly projected to the neurons of L4 and L5 DRG and that of "Ruzhong" acupoint projected to the neurons of T4, T5 and T6 DRG; sensory nerve terminals of "Zusanli" or "Ruzhong" acupoint were activated by the EA stimulation along meridians, their ability of uptaking HRP was enhanced, so the HRP labeled cells increased in the related DRG, the HRP labeled DRG segments spread. This study provides a new morphological evidence for the mechanism's explanation of propagated sensation along the meridians.

[Segmental influence of dorsal root action potentials evoked by stimulating the acupoints after acupuncture along meridians]

Using the method of recording the corresponding dorsal root action potentials evoked by stimulating the acupoints, we found that electro-acupuncture could not only expand the segmental of potentials, but also amplitude the potentials. The results proved the acupuncture sensation may be transsegmental afferent after acupuncture along the meridians. This study gave a new evidence for the mechanism's explanation of propagated sensation along the meridians.

Sterol utilization and metabolism by Heliothis zea

Heliothis zea (corn earworm), an insect that fails to synthesize sterols de novo, was reared on an artificial diet treated with 18 different sterol supplements. Larvae did not develop on a sterol-less medium. delta 5-Sterols with a hydrogen atom, a methylene group, an E- or Z-ethylidene group, or an alpha- or beta-ethyl group (cholesterol, ostreasterol, isofucosterol, fucosterol, sitosterol, and clionasterol, respectively) at position C-24, and delta 5-sterols doubly substituted in the side chain at C-24 with an alpha-ethyl group and at C-22 with a double bond (stigmasterol) supported normal larval growth to late-sixth instar (prepupal: maturity). The major sterol isolated from each of these sterol treatments was cholesterol, suggesting that H. zea operates a typical 24-dealkylation pathway. The sterol requirement of H. zea could not be met satisfactorily by derivatives of 3 beta-cholestanol with a 9 beta, 19-cyclopropyl group, gem dimethyl group at C-4, a delta 5,7-bond or delta 8-bond, or by side chain modified sterols that possessed a delta 25(27)-24 beta-ethyl group, delta 23(24)-24-methyl group or 24-ethyl group, or delta 24(25)-24-methyl or 24-ethyl group. The major sterol recovered from the larvae (albeit developmentally arrested larvae) treated with a nonutilizable sterol was the test compound. Sterol absorption was related to the degree of sterol utilization. The most effective sterols absorbed by the insect ranged from 27 to 66 micrograms per insect, whereas the least effective sterols absorbed by the insect ranged from 0.6 to 6 micrograms per insect. Competition experiments using different proportions of cholesterol and 24-dihydrolanosterol (from 9:1 to 1:9 mixtures) indicated that abnormal development of H. zea may be induced on less than a 1 to 1 mixture of utilizable (cholesterol) to nonutilizable (24-dihydrolanosterol) sterols. The results demonstrate new structural requirements for sterol utilization and metabolism by insects, particularly with respect to the position of double bonds in the side chain and functionalization in the nucleus. The novel sterol specificities observed in this study appear to be associated with the dual role of sterols as membrane inserts (nonmetabolic) and as precursors to the ecdysteroids (metabolic).

Single-agent high-dose melphalan salvage therapy for Hodgkin's disease: cost, safety, and long-term efficacy

BACKGROUND

Few data are available on the cost, safety, and long-term efficacy of single-agent high-dose melphalan (HDM) followed by autologous bone marrow (ABMT) or blood stem cell (ABSCT) transplantation in the salvage therapy of Hodgkin's disease (HD).

PATIENTS AND METHODS

From February 1981 to September 1996, 23 patients with relapsed (n = 15) or refractory (n = 8) HD received salvage therapy with HDM 140-200 mg/m2 followed by non-cryopreserved ABMT (n = 18) or cryopreserved ABSCT (n = 5). The cost of HDM/ABSCT in 1996, from initial consultation until transfer back to referring physician, was determined and compared to the estimate costs of two multi-agent regimens commonly used for HD.

RESULTS

HDM was well tolerated with no early transplant-related mortality. The five-year overall and progression-free survival rates were 52% and 50%, respectively. The average total cost in Canadian funds of HDM/ABSCT in 1996 was $34,400/patient. This cost was estimated to be $4,700-6,800 cheaper per patient than the multi-agent high-dose regimens.

CONCLUSION

These data suggest that HDM is safe, feasible, active, and reasonably inexpensive salvage therapy for patients with relapsed/refractory HD.

[Regulation of NGF on intra-synaptosomal free [Ca2+]i in mouse brain]

In the present study, the influence of direct intrahippocampal injection of NGF (nerve growth factor) on synaptosomal free [Ca2+]i in 1-month-old and 18-month-old mice was observed. The regulation of NGF on synaptosomal free [Ca2+]i in vitro was also investigated. The synaptosomal free [Ca2+]i in the main brain regions (cerebral cortex, hippocampus, cerebellum, diencephalon) of these mice was measured by fluorescent probe Fura-2 of Ca2+ indicator and an AR-CM-MIC cation measurement system. The results are as follows: (1) NGF showed no detectable effect on hippocampal intrasynaptosomal free [Ca2+]i in 1-month-old mice, but appropriate dose of NGF was shown to markedly reduce [Ca2+]i in 18-month-old mice. (2) Under the condition of low [Ca2+]i level caused by the drug, NGF was found to increase [Ca2+]i; conversely, was reduced [Ca2+]i when intracellular Ca2+ was overloaded. These results suggest that NGF has dual regulation on Ca2+ level in brain and this might be an important mechanism for its action in improving memory lesion, in aged person.

A mutational analysis of residues essential for ligand recognition at the human P2Y1 receptor

We conducted a mutational analysis of residues potentially involved in the adenine nucleotide binding pocket of the human P2Y1 receptor. Mutated receptors were expressed in COS-7 cells with an epitope tag that permitted confirmation of expression in the plasma membrane, and agonist-promoted inositol phosphate accumulation was assessed as a measure of receptor activity. Residues in transmembrane helical domains (TMs) 3, 5, 6, and 7 predicted by molecular modeling to be involved in ligand recognition were replaced with alanine and, in some cases, by other amino acids. The potent P2Y1 receptor agonist 2-methylthio-ATP (2-MeSATP) had no activity in cells expressing the R128A, R310A, and S314A mutant receptors, and a markedly reduced potency of 2-MeSATP was observed with the K280A and Q307A mutants. These results suggest that residues on the exofacial side of TM3 and TM7 are critical determinants of the ATP binding pocket. In contrast, there was no change in the potency or maximal effect of 2-MeSATP with the S317A mutant receptor. Alanine replacement of F131, H132, Y136, F226, or H277 resulted in mutant receptors that exhibited a 7-18-fold reduction in potency compared with that observed with the wild-type receptor. These residues thus seem to subserve a less important modulatory role in ligand binding to the P2Y1 receptor. Because changes in the potency of 2-methylthio-ADP and 2-(hexylthio)-AMP paralleled the changes in potency of 2-MeSATP at these mutant receptors, the beta- and gamma-phosphates of the adenine nucleotides seem to be less important than the alpha-phosphate in ligand/P2Y1 receptor interactions. However, T221A and T222A mutant receptors exhibited much larger reductions in triphosphate (89- and 33-fold versus wild-type receptors, respectively) than in diphosphate or monophosphate potency. This result may be indicative of a greater role of these TM5 residues in gamma-phosphate recognition. Taken together, the results suggest that the adenosine and alpha-phosphate moieties of ATP bind to critical residues in TM3 and TM7 on the exofacial side of the human P2Y1 receptor.

[Determination on the glycosyl sequence of gypenoside A by TLC-FABMS]

The glycosyl sequence of gypenoside A (A) isolated from Gynostemma pentaphyllum Makino was determinated by TLC-FABMS. The gypenoside A was hydrolysed with cellulase and the hydrolysate showed eight spots on a TLC plate, and the FABMS analysis of these spots indicated they corresponded to gypenoside A, A-Rham, A-Glu, A-Rham-Glu, A-Rham-Glu, A-Glu-Glu, A-Rham-2Glu, A-Rham-2Glu in order. Two chains can be determined to be Rham-Glu, and Glu-Glu, respectively. So the glycosyl sequence of gypenoside A was identical of gypenoside XLIII.

Substrate-based inhibitors of the (S)-adenosyl-L-methionine:delta24(25)- to delta24(28)-sterol methyl transferase from Saccharomyces cerevisiae

A series of 31 side-chain-modified analogs of cholesterol, zymosterol, lanosterol, and cycloartenol and the steroidal alkaloids solasodine and solanidine were studied as inhibitors of (S)-adenosyl-L-methionine:delta24(25)-sterol methyl transferase (SMT) enzyme activity from Saccharomyces cerevisiae. Two classes of sterol methylation inhibitors were tested: substrate analogs, including mechanism-based inhibitors, and transition state analogs. Several novel sterol methylation inhibitors that contained an aza, aziridine, or ammonium group in the sterol side chain were prepared and tested for the first time. The degree and kinetic pattern of methylation inhibition were found to be influenced by the position and nature of the variant functional group introduced into the side chain. The most potent inhibitors of SMT enzyme activity were transition state analog inhibitors (Ki values of 5 to 10 nM) that mimicked the structure and conformation of the natural substrate presumed to form in the ternary complex generated in the transition state. Steroidal alkaloids were potent competitive inhibitors with Ki values ranging from 2 to 30 microM, which is about the Kmapp of zymosterol, ca. 27 microM. An isosteric analog of the natural substrate, zymosterol, in which the 26/27-gem-dimethyl groups were joined to form a cyclopropylidene function is shown to be a potent irreversible mechanism-based inactivator of SMT enzyme activity that exhibits competitive-type inhibition, Ki 48 microM with a K(inact) of 1.52 min(-1). Mechanistic implications of these results provide new insights into the topology of the ternary complex involving sterol-AdoMet-enzyme.

Two-hybrid cloning of a gene encoding TNF receptor-associated protein 2, a protein that interacts with the intracellular domain of the type 1 TNF receptor: identity with subunit 2 of the 26S protease

A protein that binds the intracellular domain of the type 1 TNFR (TNFR-1IC) has been identified by two-hybrid cloning. The 97-kDa TNFR-associated protein, TRAP2, shows sequence identity with internal amino acid sequences from subunit 2 of the 26S protease. TRAP2 antiserum recognizes subunit 2 of the 26S protease, which is consistent with the identity of these proteins. TRAP2 antiserum interacted with the 97-kDa protein in HeLa cell lysates and cytosol, the latter observation showing that TRAP2 resides in the same cellular compartment as TNFR-1IC. A fusion of glutathione-S-transferase and TNFR-1IC (GST-TNFR-1IC) precipitated TRAP2 from a HeLa cell lysate; conversely, GST-TRAP2 precipitated TNFR-1 from such a lysate. These observations show that the proteins interact in the cellular milieu. After in vitro transcription/translation and 35S labeling, TRAP2 was precipitated from a cellfree system by GST-TNFR-1IC, showing that TNFR-1IC and TRAP2 interact directly. TRAP2 was also precipitated from the cellfree translation system by a GST fusion containing the N-terminal half of TNFR-1IC, but not by a GST fusion containing the C-terminal half of TNFR-1IC that contains a "death domain" that plays an obligatory role in signaling cytotoxicity. The ability of deletion mutants of TNFR-1IC to interact with TRAP2 was tested using the two-hybrid system. This also showed that the amino acid sequences that mediate binding reside outside of the death domain in TNFR-1IC. The demonstration that a subunit of the 26S protease binds TNFR-1 may identify a novel TNF-signaling pathway.

Two-hybrid cloning of a gene encoding TNF receptor-associated protein 2, a protein that interacts with the intracellular domain of the type 1 TNF receptor: identity with subunit 2 of the 26S protease

A protein that binds the intracellular domain of the type 1 TNFR (TNFR-1IC) has been identified by two-hybrid cloning. The 97-kDa TNFR-associated protein, TRAP2, shows sequence identity with internal amino acid sequences from subunit 2 of the 26S protease. TRAP2 antiserum recognizes subunit 2 of the 26S protease, which is consistent with the identity of these proteins. TRAP2 antiserum interacted with the 97-kDa protein in HeLa cell lysates and cytosol, the latter observation showing that TRAP2 resides in the same cellular compartment as TNFR-1IC. A fusion of glutathione-S-transferase and TNFR-1IC (GST-TNFR-1IC) precipitated TRAP2 from a HeLa cell lysate; conversely, GST-TRAP2 precipitated TNFR-1 from such a lysate. These observations show that the proteins interact in the cellular milieu. After in vitro transcription/translation and 35S labeling, TRAP2 was precipitated from a cellfree system by GST-TNFR-1IC, showing that TNFR-1IC and TRAP2 interact directly. TRAP2 was also precipitated from the cellfree translation system by a GST fusion containing the N-terminal half of TNFR-1IC, but not by a GST fusion containing the C-terminal half of TNFR-1IC that contains a "death domain" that plays an obligatory role in signaling cytotoxicity. The ability of deletion mutants of TNFR-1IC to interact with TRAP2 was tested using the two-hybrid system. This also showed that the amino acid sequences that mediate binding reside outside of the death domain in TNFR-1IC. The demonstration that a subunit of the 26S protease binds TNFR-1 may identify a novel TNF-signaling pathway.

[The role of insulin resistance in the clustering of cardiovascular risk factors]

The coexistence of multiple cardiovascular risk factors in the same individual is called a clustering of cardiovascular risk factors. Many studies have shown that this phenomenoa is associated with a increased morbility of cardiovascular disease, and insulin resistance may be the common link between the risk factors. This study was designed to link the clustering of cardiovascular risk factors with insulin resistance. Using a new insulin sensitivity index [-log (fasting serum Glu x Ins)] to evaluate the insulin resistance, we investigated the relationship between the insulin sensitivity and cardiovascular risk factors in 106 patients with hypertension or coronary heart disease and 32 normal subjects. The normal group without cardiovascular risk factors was selected as controls. The individual with 2 risk factors were defined as having mild clustering, and those with > or = 3 risk factors as severe clustering. As the number of risk factors increased from 1 to > or = 3, the insulin sensitivity index increased from -1.69 +/- 0.24, -1.95 +/- 0.17 to -2.14 +/- 0.21 respectively. The insulin resistance was positively correlated with serum uric acid in women (P < 0.05), but not in men (P > 0.05). The insulin sensitivity was more decreased in postmenopausal than in pre-menopausal women. The insulin sensitivity index was -2.23 +/- 0.39 vs -1.73 +/- 0.13 (P < 0.05). The insulin resistance is associated with a clustering of risk factors of cardiovascular disease, more cluste-ring, more resistant.

[The study of mutation in exon 17 of insulin receptor gene in essential hypertensive pedigrees]

Using the molecular scanning technique of single-stranded conformational polymorphism, we examined the exon 17 of the insulin receptor (INSR) gene in 44 subjects of 6 essential hypertensive pedigrees and 2 normotensive pedigrees. In addition the serum levels of glucose and insulin during an oral glucose tolerance test (OGTT); blood lipid, and plasma angiotension II and angiotensinogen were done on these pedigrees. Upon direct sequence analysis, 5 individuals were found a single nucleotide substitution at the codon 1058 (CAC-->CAT), which didn't change the amino acid sequence. Among the five individuals 4 of them were from the families with history of hypertension, only one was from normotensive pedigree. Compared with those without the mutation, the individuals with the mutation had a lower ratio of fasting blood glucose to fasting serum insulin level (P < 0.01) and an elevated plasma Ang II concentration. (There was no significant difference, P > 0.05, probably due to the mutant cases which we studied were small). Thus, we conjectured that the mutation in codon 1,058 of the INSR gene might be related with the insulin resistance in hypertensive patients and subjects with the positive hypertensive history.

Umbilical cord blood lead levels in Shanghai, China

This study was designed to determine the cord blood lead (BPb) levels of babies born in one urban area of Shanghai, and to preliminarily identify the demographic, social environment and prenatal factors which have an effect on the cord BPb concentrations. From August to November 1993, umbilical cord blood samples were obtained from 605 live newborns in the Yangpu Maternal and Child Hospital. 257 samples were excluded from measurement because of clotting. In 348 cord samples, the geometric mean of cord BPb levels was 9.2 micrograms/dl, with a 95% confidence interval of the mean 8.86-9.54 (micrograms/dl). 142 babies (40.8%) had cord BPb levels of 10 micrograms/dl or greater. As a result of this high percentage of newborns with BPb levels equal to or greater than 10 micrograms/dl, we estimate that each year in the Shanghai City about 60,000 newborns are at risk for developing neuropsychological deficiencies caused by maternal lead exposure during pregnancy. To investigate the factors affecting cord blood levels, the subjects with levels greater than the 70th percentile (10.7 micrograms/dl) (n = 104) and less than the 30th percentile (7.4 micrograms/dl) (n = 104) were selected to compare the demographic, environment and prenatal medical history. Increased BPb levels at birth were associated with maternal passive smoking, a family member being occupationally exposed to lead, proximity to major traffic way, household coal combustion, neighborhood coal combustion, low level of maternal occupations, and the increasing occurrence of having the high lead foodstuff pidan (preserved duck egg) during pregnancy. We conclude that prenatal lead exposure has become an important health issue for young children in Shanghai.

Prediction of mutant activity and its application in molecular design of tumor necrosis factor-alpha

Two models for prediction of the activity and stability of site-directed mutagenesis on tumor necrosis factor-alpha are established. The models are based on straightforward structural considerations, which do not require the elaboration of sitedirected mutagenesis on the protein core and the hydrophobic surface area by analyzing the pmperties of the mutated amino acid residues. The reliabilities of the models have been tested by analyzing the mutants of tumor necrosis factor-alpha (TNF-alpha) whose two leucine residues (L29, L157) were mutated. Based on these models, a TNFalpha mutant with high activity was created by molecular design.

Efficient insertion of odd-numbered transmembrane segments of the tetracycline resistance protein requires even-numbered segments

Functional membrane insertion elements in the pBR322 tetracycline resistance protein were identified by comparing the ability of odd-numbered transmembrane segments and their attached periplasmic loops to insert into the membrane individually or when combined with the next even-numbered segment in the tetracycline resistance protein sequence. The efficiency with which individual odd-numbered segments and periplasmic loops inserted was probed by treating proteins truncated at the distal ends of periplasmic loops P2-P6 with carboxypeptidases and endoproteases in inside-out membrane vesicles. Insertion of odd-numbered segments and attached loops is inefficient when they occupy a C-terminal position in the protein. The C-terminal odd-numbered segment and loop sequences of 34-54% of the molecules of periplasmic loop truncation mutants could be removed by carboxypeptidase Y. In contrast, odd-numbered segments and loops insert efficiently if the next even-numbered segment in the sequence is present. In such cytoplasmic loop truncation mutants, only the cytoplasmic tail sequences of the proteins could be removed by carboxypeptidases. Remarkably, insertion of individual odd-numbered segments and loops is inefficient even though free energies for insertion of these sequences are highly favorable. The results indicate that pairs of adjacent segments, possibly "helical hairpins," are necessary for efficient membrane insertion of the tetracycline resistance protein.

Inhibition of tumor necrosis factor signal transduction in endothelial cells by dimethylaminopurine

Tumor necrosis factor (TNF) promotes diverse responses in endothelial cells that are important to the host response to infections and malignancies; however, less is known of the postreceptor events important to TNF action in endothelial cells than in many other cell types. Since phosphorylation cascades are implicated in cytokine signaling, the effects of the protein kinase inhibitor dimethylaminopurine (DMAP) on TNF action in bovine aortic endothelial cells (BAEC) were investigated. In BAEC, TNF promotes phosphorylation of eukaryotic initiation factor 4E (eIF-4E), c-Jun N-terminal kinase (JNK) and ceramide-activated protein kinase activities, Jun-b expression, prostacyclin production, and, when protein synthesis is inhibited, cytotoxicity. DMAP abrogated or significantly attenuated each of these responses to TNF, without affecting the specific binding of TNF to its receptors. Histamine, another agent active in the endothelium, promotes phosphorylation of elongation factor-2 (EF-2) and prostacyclin production, but not phosphorylation of eIF-4E in BAEC. Histamine-stimulated EF-2 phosphorylation was not inhibited and prostacyclin production was unaffected by DMAP. These observations demonstrate that a distinct signal transduction cascade, which can be selectively inhibited by DMAP, promotes the response of BAEC to TNF. Thus, we have identified a reagent, DMAP, that may be useful for characterizing the TNF signal transduction pathway.

[Loss of p16 gene in bladder cancer and genitourinary carcinoma cell lines]

To determine whether p16, a novel antioncogene, is altered in human bladder cancer and urogenital carcinoma cell lines, we examined a series of 10 primary bladder cancer and 4 urogenital carcinoma cell lines (BIU-87, EJ, GRC and PC-3M) by southern blot. Two cases of 10 primary bladder cancer and EJ, BIU-87 PC-3M had homozygous deletion of p16, and 2 cases of 10 primary bladder cancer had loss of heterozygous. Loss of p16 may provide an additional growth advantage and carcinogenesis.