The unique amino-terminal peptide of cardiac troponin I regulates myofibrillar activity only when it is phosphorylated

Protein kinase A (PKA) dependent phosphorylation of C-protein and cardiac troponin I (cTnI) is known to be associated with a reduced sensitivity to Ca2+. We have investigated the relative importance of each of these sites of phosphorylation in this effect by use of extraction/reconstitution experiments and mutagenesis of recombinant cTnI. Conditions developed for extraction of troponin (Tn) complex also resulted in extraction of C-protein. A truncated cTnI (cTnI/NH2) lacking the 32 amino acids in the unique amino terminal extension of cTnI was engineered and expressed. In contrast to native cTnI, cTnI/NH2, which lacks Ser23 and Ser24, was not phosphorylated by PKA either in pure form or after incorporation into the myofilament lattice. The relation between pCa (-log molar free Ca2+ concentration) and MgATPase activity of non-phosphorylated native myofibrils or non-phosphorylated myofibrils reconstituted with cTnI, but lacking C-protein, was the same and could not be distinguished from that of control or PKA-treated myofibrils into which we exchanged cTnI with cTnI/NH2. However, PKA-dependent phosphorylation of either native myofibrils or reconstituted myofibrils containing cTnI but lacking C-protein resulted in an identical and significant rightward shift of pCa50 (half-maximally activating pCa) in the pCa-activity relationship. Our results strongly indicate that phosphorylation of cTnI at Ser residues in the unique amino terminal extension of the molecule is both necessary and sufficient for the decrease in myofilament Ca(2+)-sensitivity associated with PKA-dependent phosphorylation.

Ca2+ and cAMP activate different K+ conductances in the human intestinal goblet cell line HT29-Cl.16E

The mechanism of regulated Cl- secretion was evaluated in the mucin-secreting cell line HT29-Cl.16E by transepithelial electrophysiology and fura 2 measurements of cytosolic Ca2+. Carbachol by itself was a weak secretagogue, but augmented adenosine 3',5'-cyclic monophosphate (cAMP)-mediated secretion more than twofold, consistent with activation of a rate-limiting K+ conductance. To characterize this conductance, monolayers were apically permeabilized with amphotericin B. At least two types of K+ conductances were identified. One type was activated by elevated cytosolic cAMP levels and inhibited by Ba2+ (inhibitor constant 0.3 mM) in the basolateral solution but was not affected by quinidine or elevated cytosolic Ca2+. The other type was activated by carbachol via cytosolic Ca2+ and was partially inhibited by quinidine (60% inhibition by 2.5 mM quinidine) but was not affected by Ba2+ up to 1 mM. Both conductances appear to be involved in active, transepithelial Cl- secretion in intact monolayers but under different conditions because 1) the cAMP-stimulated short-circuit current (Isc) can be partially inhibited by 1 mM Ba2+ (50%) but not quinidine, 2) the Ba2+ inhibition does not affect the carbachol-induced increase in Isc in cells with elevated cAMP levels, and 3) the carbachol-dependent Isc can be inhibited by quinidine. Therefore, the contribution of the cAMP-dependent K+ conductance appears important for maintaining the membrane potential and therewith Cl- secretion when cAMP is the only messenger for secretion signals, whereas the Ca(2+)-dependent K+ conductance is responsible for the carbachol-stimulated increase in Isc.

Efficient selection of recombinant adenoviruses by vectors that express beta-galactosidase

Adenovirus serotype 5 vectors which contain the Excherichia coli beta-galactosidase gene driven by the cytomegalovirus immediate-early promoter as a screenable marker have been made and successfully used in the construction of recombinant adenoviruses. The beta-galactosidase gene has been introduced into viruses in which the E3 region is maintained or deleted and in which the cis-acting packaging sequence has been reiterated at the right end of the chromosome. A unique BstBI site has been introduced 3' of the beta-galactosidase gene. Cotransfection of BstBI-digested vector DNA and a plasmid containing the left end of the viral chromosome followed by staining with X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside) results in clear plaques when overlap recombination has occurred and blue plaques when ligation of the viral arms has occurred within the host cell. The beta-galactosidase-expressing viruses grow to lower titers than do the parental viruses, leading to a relative growth advantage for viruses resulting from overlap recombination. Combined with color selection based on the beta-galactosidase gene, this system permits efficient production and selection of recombinant viruses after cotransfection of BstBI-digested viral DNA with a plasmid including left-end viral sequences and the gene of interest. The beta-galactosidase-expressing viral DNAs were used to construct viruses containing BstBI sites on either side of the cis-acting packaging element as a means of testing their utility.

A case-control study of the etiology of laryngeal cancer in Liaoning Province

A case-control study of laryngeal cancer was conducted in Liaoning Province between January 1991 and April 1992 among 100 subjects with newly diagnosed cancer and 100 controls. The results of one factor analysis, odd ratio (OR), and conditional logistic regression indicated that smoking was the first significant risk factor for laryngeal cancer with an OR value of 16.8. Tobacco smoking ranked the first with an OR value of 30.4. Other factors such as alcoholic indulgence, insufficient intake of vegetable and fruits in winter and spring, air pollution in room and working environment, and fatigue of vocal cords were closely associated with the occurrence of laryngeal cancer.

5-Fluoro-2-pyrimidinone, a liver aldehyde oxidase-activated prodrug of 5-fluorouracil

5-Fluorouracil (5-FU) is an effective antitumor agent used in treating various cancers. Because of its metabolism by intestinal and other cells, 5-FU has an inconsistent bioavailability that limits its oral use. 5-Fluoro-2-pyrimidione (5-FP), a 5-FU prodrug, was synthesized and found to be converted to 5-FU by aldehyde oxidase, an enzyme present in high concentrations in the livers of mice and humans but not in the gastrointestinal tract. Using BDF1 mice, the pharmacokinetics of 5-FP were studied and compared with those of 5-FU. The bioavailability of 5-FP given orally was 100% at a dosage of 25 mg/kg and 78% at a dosage of 50 mg/kg. The half-lives of both doses of 5-FP were at least 2-fold longer than the half-lives of the same doses of 5-FU, and the clearance rates of 5-FP were 3-fold slower. 5-FP was converted rapidly to 5-FU, in vivo. The resulting 5-FU was measured at a steady-state level of 40-70 microM in plasma, at a dosage of 25 mg/kg, that was sustained for at least 4 hr. Also, when given orally, 5-FP was shown to have potent activity against Colon 38 tumor cells and P388 leukemia cells in mice. The therapeutic index of 5-FP was similar to that of 5-FU in these mouse tumor models. The potential clinical use of 5-FP as a prodrug of 5-FU should be considered.

Hemocyte alterations during melanotic encapsulation of Brugia malayi in the mosquito Armigeres subalbatus

The involvement of hemocytes in melanotic encapsulation reactions against Brugia malayi was assessed in Armigeres subalbatus. Hemocyte populations, epitope changes, phenol oxidase (PO) activity, and the presence of an 84-kDa polypeptide were investigated in mosquitoes exposed to a B. malayi-infective bloodmeal (= immune-activated), in mosquitoes given a noninfective bloodmeal (= controls), in nonbloodfed mosquitoes (= naive), or in some combination of these. Total hemocyte populations in immune-activated mosquitoes significantly decreased at 24 hr postbloodmeal (PB) as compared with controls. At 48 and 72 hr PB, hemocyte population levels in immune-activated mosquitoes increased to control levels. Epitope changes, as indicated by wheat germ agglutinin (WGA) binding, also were observed. There was a significant increase in the percentage of hemocytes binding WGA in immune-activated mosquitoes at 24 hr PB as compared with controls. Furthermore, the activity of hemocyte PO, an enzyme involved in the melanotic encapsulation pathway, was significantly elevated at 12 hr PB in immune-activated mosquitoes as compared with controls. Analysis for the presence of an 84-kDa polypeptide in A. subalbatus indicates that a 2.0-kb message in total RNA hybridized to D6.12, an Aedes aegypti cDNA encoding an 84-kDa polypeptide that is associated with melanotic encapsulation responses. The hybridization of D6.12 to RNA was not greater in immune-activated as compared to control A. subalbatus, as has been observed in A. aegypti. Results indicate that these hemocyte changes correspond in time with the melanotic encapsulation reactions of A. subalbatus against filarial worms.

Effect of hepatocytes from normal or endotoxin treated animals on the production of tumour necrosis factor, interleukin-6, and prostaglandin-E2 by macrophages incubated in vitro with various fatty acids

OBJECTIVE

To find out if the in vitro production of tumour necrosis factor (TNF), interleukin 6 (IL-6) and prostaglandin E2 (PGE2) by macrophages (P3888D1) were influenced by the addition to the culture media of hepatocytes from normal guinea pigs and from guinea pigs after infusion with endotoxin with and without fatty acids.

DESIGN

Laboratory experiment.

SETTING

University hospital, United States

MATERIAL

12 male Hartley guinea pigs.

MAIN OUTCOME MEASURES

Concentrations of TNF-alpha, IL-6, and PGE2.

RESULTS

Hepatocytes inhibited the production of TNF by macrophages. Those from animals pretreated with endotoxin caused a large increase in the production of PGE2 and affected the production of IL-6 only in the presence of fatty acids. Fatty acids differed from each other in their effects on production of TNF-alpha and PGE2, but had no effect on the production of IL-6.

CONCLUSION

These results support the concept that hepatocytes and macrophages may interact in vivo, and this interaction may be influenced both by fatty acids that arise from lipid metabolism and from endotoxin present during sepsis and translocation.

Identification of a ras-activated enhancer in the mouse osteopontin promoter and its interaction with a putative ETS-related transcription factor whose activity correlates with the metastatic potential of the cell

The role of RAS in transducing signals from an activated receptor into altered gene expression is becoming clear, though some links in the chain are still missing. Cells possessing activated RAS express higher levels of osteopontin (OPN), an alpha v beta 3 integrin-binding secreted phosphoprotein implicated in a number of developmental, physiological, and pathological processes. We report that in T24 H-ras-transformed NIH 3T3 cells enhanced transcription contributes to the increased expression of OPN. Transient transfection studies, DNA-protein binding assays, and methylation protection experiments have identified a novel ras-activated enhancer, distinct from known ras response elements, that appears responsible for part of the increase in OPN transcription in cells with an activated RAS. In electrophoretic mobility shift assays, the protein-binding motif GGAGGCAGG was found to be essential for the formation of several complexes, one of which (complex A) was generated at elevated levels by cell lines that are metastatic. Southwestern blotting and UV light cross-linking studies indicated the presence of several proteins able to interact with this sequence. The proteins that form these complexes have molecular masses estimated at approximately 16, 28, 32, 45, 80, and 100 kDa. Because the approximately 16-kDa protein was responsible for complex A formation, we have designated it MATF for metastasis-associated transcription factor. The GGANNNAGG motif is also found in some other promoters, suggesting that they may be similarly controlled by MATF.

Effects of marker information on sib-pair linkage analysis of a rare disease

Model-free sib-pair linkage analysis was used to screen the GAW9-Problem 1 data set for evidence of linkage of a rare disease to any of 360 highly polymorphic marker loci. Negative regressions nominally significant at the alpha = 0.05 level were obtained for 44 markers; however all of these proved to be Type I errors. None of the four disease loci were detected by sib-pair linkage, which was not surprising, given the particular model and sampling scheme used to generate these data. Neither deleting parental marker genotypic information nor misspecifying marker allele frequency estimates substantially increased the Type I error rate. A two-stage testing procedure using a 10 or 20 cM map and a liberal first stage significance level gave the same overall results as a one-stage 2 cM map but required only about 42% or 22% as many markers, respectively.

Reproductive Potential and Genetics of Triploid Pacific Oysters, Crassostrea gigas (Thunberg)

The reproductive potential and genetics of triploidy were studied in the Pacific oyster. DNA content in sperm from triploids showed a single peak at 1.5c as determined by flow cytometry. In eggs from triploids, trivalents were the dominant form of synapsed chromosomes, although the degree of synapsis varied considerably within and among females. Some eggs went through complete synapsis and formed 10 trivalents, chromosomes; most had a mixture of 11-13 trivalents, bivalents, and univalents. Factorial matings were produced from diploid (D) and triploid (T) parent oysters, creating four crosses: DD, DT, TD, and TT (female first). Gametes from triploids were fully capable of fertilization. After fertilization, eggs from triploids went through two meioses and released two polar bodies as diploid eggs did. Karyological analyses showed that average ploidy of the resultant embryos was 2.0 n for DD, 2.46 n for DT, 2.52 n for TD, and 2.88 n for TT. Survival of fertilized eggs to metamorphosis and settlement was about 21% for DD, but considerably lower on other crosses: 0.0007% for DT, 0.0463% for TD, and 0.0085% for TT. Nine months after matings, all survivors from DT crosses were diploid. Survivors from TD crosses consisted of 33% diploids, 57% triploids, and 10% tetraploids. Survivors from the TT crosses consisted of 90% triploids, 4% diploids, and 6% mosaics. We hypothesize that differences in ploidy composition between DT and TD embryos and survivors were caused by pro-egg segregations that favor the retention, rather than loss, of extra chromosomes in the egg. The reproductive potential of triploids and evolutionary implications are discussed.

Sex determination and polyploid gigantism in the dwarf surfclam (Mulinia lateralis Say)

Mulinia lateralis, the dwarf surfclam, is a suitable model for bivalve genetics because it is hardy and has a short generation time. In this study, gynogenetic and triploid M. lateralis were successfully induced. For gynogenesis, eggs were fertilized with sperm irradiated with ultraviolet light and subsequently treated with cytochalasin B to block the release of the second polar body (PB2). Triploidy was induced by blocking PB2 in normally fertilized eggs. The survival of gynogenetic diploids was very low, only 0.7% to 8 days post-fertilization (PF), compared with 15.2% in the triploid groups and 27.5% in the normal diploid control. Larvae in all groups metamorphosed at 8-10 days PF, and there was no significant post-larval mortality. At sexual maturation (2-3 months PF), all gynogenetic diploids were female, and there was no significant difference (P > 0.05) in sex ratio between diploids and triploids. These results suggested that the dwarf surfclam may have an XX-female, XY-male sex determination with Y-domination. Compared with diploids, triploids had a relative fecundity of 59% for females and 80% for males. Eggs produced by triploid females were 53% larger (P < 0.001) in volume than those from diploid females. In both length and weight measurements at three months PF, the gynogenetic diploids were not significantly (P > 0.33) different from normal diploid females, suggesting that inbreeding depression was minimal in meiosis II gynogens. Triploid clams were significantly larger (P < 0.001) than normal diploids. We hypothesize that the increased body-size in triploids was caused by a polyploid gigantism due to the increased cell volume and a lack of cell-number compensation.

Immunohistochemistry of cyclin D1 in human breast cancer

Cyclin D1/PRAD 1, a cell cycle-related gene mapped to chromosome 11q13, has been found to be amplified in some breast cancers and squamous cell carcinomas of the head and neck, and esophagus. In this study, overexpression of cyclin D1/PRAD1 gene was demonstrated immunohistochemically in 35 of 43 (81.3%) cases of human breast cancer, with a newly available anticyclin D antibody. Neither normal epithelial components nor glandular structures from samples of fibrocystic disease, were reactive. Amplification of the gene was detected in 4 of 23 (17%) cases by Southern analysis. Increased gene dosage does not seem to be the only mechanism that resulted in increased protein expression as detected by immunohistochemistry. Because the less differentiated high grade tumors exhibited a more intense nuclear stain and non-neoplastic epithelial components were not stained, the use of cyclin D1/PRAD1 has potential as a tumor marker.

The body mass index of Chinese adults in the 1980s

Patterns and trends in the body composition of Chinese adults are studied with data from the 1982 China Nationwide Nutrition Survey (CNS-82) and the 1989 China Health and Nutrition Survey (CHNS-89). The CNS-82 showed rural inhabitants were approximately 3 kg lighter than urban residents and approximately 2.2 cm shorter. Males were heavier (55.2 +/- 7.4 vs 50.7 +/- 8.0 kg) and taller (165.3 +/- 7.3 and 153.5 +/- 6.3 cm). Using a cut-off for underweight of a body mass index (BMI: kg/m2) < 18.5 and for obesity of > 25, 11.6% and 12.9% of the urban and rural sample were underweight and 9.8% and 6.9% respectively were overweight. The CHNS-89 surveyed 5138 adults aged 20-45 in eight selected provinces. The proportion of underweight in both urban and rural samples declined slightly (approximately 1.3%) but the proportion of obesity increased considerably (4.8% for the urban sample and 2% for the rural one). Increased income was significantly associated with reduced low body mass index (BMI: kg/m2) in the urban sample while, for the rural and overall samples, the opposite was found for obesity. Provincial patterns in energy intake were not associated with the distribution of BMI while occupation was. In particular, government officials and housewives were much more likely to be obese as also were subpopulation groups consuming greater proportions of energy from animal sources. Over 80% of the population fell in the normal BMI range (18.5-25). This may relate to the relatively even distribution of food in China during the past several decades.

[Effects of high iodine and high fluorine on children's intelligence and the metabolism of iodine and fluorine]

An investigation on children's intelligence and the metabolism of iodine and fluorine in high iodine and fluorine regions was carried out. The results were as follows. In high iodine and high fluorine areas, the thyroid enlargement prevalence rate among inhabitants and that among children were 3.8% and 29.8%, respectively. The dental fluorosis prevalence rate among inhabitants and that among children was 35.48% and 72.9%, respectively. The pupils' average intelligence quotient (IQ) was 76.67 +/- 7.75, slightly lower than the control point, but that of low intelligent pupils was 16.7%. The urinary iodine and urinary fluoride were 816.25 +/- 1.80 micrograms/L and 2.08 +/- 1.03 mg/L, respectively, markedly higher than the control point. The thyroid iodine-131 (131I) uptake rate was markedly lower than the control point. The values at 3 h and 24 h were 9.36 +/- 1.55% and 9.26 +/- 4.63%, respectively. The serum TSH was obviously higher than the control point. These results indicate that high iodine and high fluorine exert severe damage to human body.

NMR studies delineating spatial relationships within the cardiac troponin I-troponin C complex

NMR spectroscopy and selective isotope labeling of both recombinant cardiac troponin C (cTnC3) and a truncated cardiac troponin I (cTnI/NH2) lacking the N-terminal 32-amino acid cardiac-specific sequence have been used to probe protein-protein interactions central to muscle contraction. Using [methyl-13C]Met-labeled cTnC3, all 10 cTnC Met residues of Ca(2+)-saturated cTnC3 could be resolved in the two-dimensional heteronuclear single- and multiple-quantum coherence spectrum of the cTnI.cTnC complex. Based on the known Met assignments in cTnC3, the largest chemical shift changes were observed for Met81, Met120, Met137, and Met157. Methionines 120, 137, and 157 are all located in the C-terminal domain of cTnC. Methionine 81 is located at the N terminus of the central helix. Minimal chemical shift changes were observed for Met45, Met47, and Met103 of cTnC3 in the cTnI.cTnC complex. All 6 Met residues in [methyl13C]Met-labeled cTnI/NH2 could be resolved in the cTnI.cTnC complex, suggesting that both cTnI and cTnC form a stable homogeneous binary complex under the conditions of the NMR experiment. In the absence of added protease inhibitors in the cTnI.cTnC complex, cTnI/NH2 was found to undergo selective proteolysis to yield a 5.5-kDa N-terminal fragment corresponding to residues 33-80. Judging from the NMR spectra of [methyl13C]Met-labeled cTnC3, cTnI-(33-80) was sufficient for interaction with the C-terminal domain of cTnC in a manner identical to that observed for native cTnI/NH2. However, in the presence of the proteolytic fragment cTnI-(33-80), the chemical shift of Met81 was not perturbed from its position in free cTnC3. Thus, residues located C-terminal to Arg80 in cTnI appear to be responsible for interaction with the N-terminal half of cTnC. Taken together, these results provide strong evidence for an antiparallel arrangement for the two proteins in the troponin complex such that the N-terminal portion of cTnI interacts with the C-terminal domain of cTnC. This interaction likely plays a role in maintaining the stability of the TnI.TnC complex.

Cognitive brain potential alterations in boys exposed to opiates: in utero and lifestyle comparisons

Several studies have observed that intrauterine exposure to opiates results in emotional and cognitive complications for the child, but genetic and postnatal social-environmental factors may also affect the CNS development of these children. To assess the relative contribution of the in utero and social-environmental (lifestyle) effects of opiate exposure, event-related potentials (ERPs) and performance were studied in three groups of 7- to 12-year-old boys: (1) the in utero/lifestyle group (IU/LS) contained 16 boys who were exposed to opiates (in utero and lived with opiate-abusing mothers, (2) the lifestyle group (LS) included 14 boys who lived with opiate-abusing mothers, and (3) the control group (CON) composed of 13 boys. The cognitive ERP components and task performance were recorded in the Auditory Rare Event Monitoring (AREM) task and the Sternberg Memory task (Sternberg, 1975). On the AREM and Sternberg Memory tasks, P200 component was significantly decreased for the IU/LS and LS groups. On the Sternberg Memory task, percent correct was also significantly impaired in IU/LS and LS groups. The ERP alterations in the boys living with opiate-abusing mothers with and without intrauterine opiate exposure were similar. A dysfunctional social environment may contribute to the cognitive deficits seen in the sons of opiate-abusing mothers.

Mutagenesis of cardiac troponin I. Role of the unique NH2-terminal peptide in myofilament activation

Phosphorylation of Ser residues in the NH2-terminal extension unique to cardiac troponin I (cTnI) is known to occur through protein kinase A and to alter myofilament Ca2+ activation (Robertson, S. P., Johnson, J. D., Holroyde, M. J., Kranias, E. G., Potter, J. D., and Solaro, R. J. (1982) J. Biol. Chem. 257, 260-263). Yet, how the NH2-terminal extension may itself affect thin filament Ca2+ signaling is unknown. To approach this question we have used molecular cloning, mutagenesis, and bacterial synthesis of a full-length cTnI and a truncated mutant (cTnI/NH2) missing the 32 amino acids. Using reconstituted preparations we could show no differences between cTnI and cTnI/NH2 either in inhibition of actomyosin ATPase activity, in Ca(2+)-reversible inhibitory activity, or in the relation between pCa and Ca2+ binding to the regulatory site of cTnC at either pH 7.0 or 6.5. There were also no significant differences at either pH in the pCa-MgATPase activity relation of myofibrils into which the various species of TnI has been exchanged. Our results indicate: 1) that phosphorylation most likely induces a new state of TnI activity rather than altering an intrinsic effect of the NH2-terminal peptide on Ca2+ activation; and 2) that domains outside the NH2-terminal extension are important with regard to differences in effects of acidic pH on Ca2+ activation on cardiac and skeletal myofilaments.

Regression of cardiac hypertrophy and myosin isoenzyme patterns by losartan and captopril in renovascular hypertensive rats

To test the effect of losartan and captopril on cardiac hypertrophy and myosin isoenzyme, two-kidney, one-clip (2K 1C) renovascular hypertensive rats (RHR) were used. Eight weeks after the onset of hypertension, losartan 5 mg.kg-1.d-1 and captopril 50 mg.kg-1.d-1 were administered p.o. to 2 groups of RHR, respectively for 8 wk. The results showed that captopril significantly decreased the cardiac mass (607 +/- 169 mg vs 1029 +/- 132 mg) and total protein content (120 +/- 38 mg vs 198 +/- 31 mg), concomitant with significant decrease of arterial blood pressure (BP) (15.4 +/- 5.2 kPa vs 28.5 +/- 4.9 kPa). Losartan also induced a significant decrease in cardiac mass (671 +/- 116 mg vs 1029 +/- 132 mg) and protein content (142 +/- 29 mg vs 198 +/- 31 mg), as well as significantly lowered the BP (15.2 +/- 2.1 kPa vs 28.5 +/- 4.9 kPa). It is important to be note that both drugs normalized the shift of myosin isoenzyme in RHR. These results indicated that both drugs, having potent antihypertensive effects, can effectively reverse the cardiac hypertrophy and abnormal distribution of myosin isoenzyme patterns.

Production of tumor necrosis factor, interleukin-6 and prostaglandin E2 by LPS-stimulated rat bone marrow macrophages after thermal injury: effect of indomethacin

The effect of thermal injury on the in vitro production of TNF, IL-6, and PGE2 by bone marrow-derived, LPS-stimulated rat macrophages was studied. Thermal injury caused a general hyperactivity in the production of the mediators by the cells. Indomethacin, a cyclooxygenase inhibitor of PGE2 synthesis, inhibited the production of IL-6 and PGE2 but had no effect on the production of TNF. These results suggest that the observed low concentration of PGE2 produced by the cells was insufficient to cause inhibition of TNF synthesis; thus, the effect of indomethacin would be undetectable. The results also suggest that indomethacin may act directly in inhibiting the production of IL-6 by the macrophages. The hyperactive effect of thermal injury on the production of inflammatory mediators by newly differentiated bone marrow derived macrophages can be important in the overall systemic response to the insult.

Differential secretion of catecholamines in response to peptidergic and cholinergic transmitters in rat adrenals

1. Rat adrenal medulla is stimulated by cholinergic and peptidergic transmitters released from splanchnic nerves. The peptidergic transmitter has been identified as vasoactive intestinal polypeptide (VIP) and its contribution in comparison to that of acetylcholine (ACh) is more prominent at low neuronal activity. The purpose of this study is to determine if ACh and VIP cause differential secretion of adrenaline and noradrenaline and whether the differential secretion also occurs when splanchnic nerves are stimulated at different frequencies. 2. Perfusion of the left adrenal gland with Krebs solution for several hours did not change adrenaline and noradrenaline contents (15.2 micrograms and 3.5 micrograms, respectively) and their ratio (4.4) from those of the unperfused right adrenal medulla (15.2 micrograms, 3.3 micrograms and 4.8, respectively). 3. Perfusion with ACh (10 microM for 4 min) resulted in the secretion of 109 ng of catecholamines and the ratio of adrenaline to noradrenaline was 3.8. Although the secretion increased with increased concentrations of ACh (30 and 100 microM), the ratios remained between 3 and 4. 4. Perfusion with VIP (10 microM for 4 min) resulted in the secretion of 27 ng of catecholamines and the ratio of adrenaline to noradrenaline was 9.7. A higher concentration of VIP (20 microM for 4 min) resulted in the secretion of greater amounts of catecholamines (102 ng) without significantly altering the ratio of adrenaline to noradrenaline (10.9). 5. Perfusion with as low as 0.01 microM pituitary adenylate cyclase-activating polypeptide (PACAP) increased the secretion of catecholamines to 31 ng and the secretion increased in a dose-dependent manner up to 0.3 microM.(ABSTRACT TRUNCATED AT 250 WORDS)

Exocytosis from a single rat chromaffin cell by cholinergic and peptidergic neurotransmitters

Secretion of catecholamines from chromaffin cells is mediated by cholinergic and peptidergic neurotransmitters. The cholinergic transmitter acetylcholine activates both nicotinic and muscarinic receptors to trigger catecholamine secretion in rat adrenal medulla. Vasoactive intestinal polypeptide (VIP) has been identified as the peptidergic transmitter in rat adrenal medulla and may also be the non-cholinergic transmitter in bovine adrenal. Pituitary adenylate cyclase activating polypeptide (PACAP), a VIP-like secretin peptide, is also found in the adrenal, and is a potent secretagogue. Thus, PACAP may be another peptidergic transmitter at the adrenal synapse. A most intriguing property of rat chromaffin cells is that stimulation of nicotinic, muscarinic, VIP or PACAP receptors are each able to produce robust catecholamine secretion on their own. This raises the question of whether a single chromaffin cell can respond to each of the above agonists or whether the secretion is due to subpopulations of chromaffin cells. This issue was addressed by using electrochemical techniques to monitor exocytosis from individual chromaffin cells in culture. We demonstrate that acetylcholine, nicotine, muscarine, VIP and PACAP are each able to evoke catecholamine secretion from a single chromaffin cell. Some cells only responded to acetylcholine. Furthermore, each agonist produced a distinct pattern of exocytosis. Muscarine-evoked secretion exhibited a latency of 0.5-2 s, but exocytosis persisted up to 30 s following 500 ms stimulation. Nicotine produced an immediate response which usually ended within 10 s. The secretory pattern following acetylcholine appeared to be the sum of the nicotinic and muscarinic patterns, showing both rapid onset and longer duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitumor agents. 148. Synthesis and biological evaluation of novel 4 beta-amino derivatives of etoposide with better pharmacological profiles

A series of novel 4 beta-amino derivatives of etoposide (1), which can form water-soluble salts and demonstrate excellent activity against mdr- and topo II-resistant cell lines, have been synthesized. Compared with etoposide, compounds 5-6, 8, and 10-16 show comparable or greater inhibition of human DNA topo II. In a cellular protein-DNA complex formation assay, compounds 5-6, 8, 10-14, and 16 are more potent than 1. A dose-response study of 8 shows that it is 20 times more active in formation of protein-linked DNA breaks than etoposide. Furthermore, both 8 and its free base 7 were found to be highly active toward etoposide-resistant KB cell lines. All compounds were also evaluated in vitro against a total of 56 human tumor cell lines derived from seven cancer types. Comparison of the log10 GI50 mean graph midpoints of 5-19 (-4.89 to -7.30) with that of 1 (-4.08) shows these new analogs to be 6-1659-fold more active than 1.

Genome size and organization in the ixodid tick Amblyomma americanum (L.)

We used DNA reassociation kinetics to determine genome size and organization in the ixodid tick Amblyomma americanum. We calculated the genome size of A. americanum to be approximately 1.08 pg or 1.04 x 10(9) base pairs and to consist of 35.8% unique DNA, 4.2% foldback sequences, 17.9% highly repetitive sequences, and 42.1% moderately repetitive sequences. Comparison of the reassociation kinetics of long and short fragments revealed repetitive sequences to be distributed in a pattern of long period interspersion, a feature that, to date, has been associated with arthropod genomes that lack a high percentage of repetitive DNA.

[Immunoelectron microscopic studies on the process of tumor cytolysis mediated by lymphokine activated NK cells]

The second fraction (F2) cells isolated from PBL by discontinuous Percoll density gradient centrifugation were used as the enriched natural killer (NK) cells. After being incubated with rIL2, the activated F2 cells (F2 LAK) acquired the cytolytic ability upon NK resistant tumor cell lines. In F2 LAK, about 45% of the cells were CD16+, therefore F2 LAK were used as the enriched CD16+LAK cells (or lymphokine activated NK cells). The cytolysis process of lung adenocarcinoma LTEPa-2 or K562 tumor cells mediated by CD16+LAK cells were investigated with colloidal gold labelled Ab via scanning and transmission immunoelectron microscopy. The results showed that the CD16+LAK cells extended their protrusions deep into the target cells. Crypts of various diameter and depth were observed on the surface of the target cells with membrane injury at the bottom of the crypts. It was found that the cytoplasmic granules and vacuoles of CD16+LAK cells were concentrated in the area close to the E-T conjugated side, and sometimes the granules were found within the LAK protrusions. The attacked target cells died by apoptosis and necrosis. This study provided direct evidence that lymphokine activated NK cells are effectors of LAK cells.

Antitumor agents. 144. New gamma-lactone ring-modified arylamino etoposide analogs as inhibitors of human DNA topoisomerase II

The trans-fused gamma-lactone ring of etoposide is readily epimerized to its cis epimer, which is biologically inactive, or is metabolized to the inactive ring-opened hydroxy acids. Modification of this gamma-lactone ring of 4 beta-(arylamino)-4'-O-demethyl-4-desoxypodophyllotoxin resulted in several compounds (15-16, 21-22, and 24) that should block this epimerization and the resulting biological deactivation. In a topoisomerase II inhibition assay, compounds 21, 22, and 24 showed comparable activity to etoposide. In a protein-linked DNA complex formation assay, compounds 21 and 22 were more active than etoposide.

ATP-stimulated electrolyte and mucin secretion in the human intestinal goblet cell line HT29-Cl.16E

The response of confluent monolayers of HT29-Cl.16E cells to stimulation by extracellular ATP and ATP analogues was investigated in terms of mucin and electrolyte secretion. Mucin secretion was measured as release of glucosamine-labeled macromolecules trapped at the stacking/running gel interface of polyacrylamide gels and electrolyte secretion as short-circuit current (Isc). Luminal ATP stimulated a transient increase in the release of mucins and of Isc corresponding to a secretory Cl- current. Both secretions peaked at 3 to 5 min after addition of ATP. Maximal ATP-stimulated mucin secretion over 15 min was up to 18-fold above control with an apparent ED50 of approximately 40 microM. Maximal peak Isc after stimulation with ATP was approximately 35 microA/cm2 with an apparent ED50 of about 0.4 mM. ATP-dependent Isc was at least in part due to Cl- secretion since removal of Cl- from the medium reduced the peak Isc by 40% and the Isc integrated over 40 min by 80%. The secretory responses were not associated with cell damage as assessed by failure of ethidium bromide to enter into the cells, absence of release of lactate dehydrogenase, maintenance of monolayer conductance, viability, and responses to repeated applications of ATP. The order of efficacy of nucleotide agonists was similar for both processes with ATP > ADP > AMP > or = adenosine. Luminal ATP was much more effective than basolateral addition of this compound. These results suggest involvement of a luminal P2-type receptor which can initiate signaling pathways for granule fusion and mucin release as well as for activation of Cl- channels. P2-receptor-stimulated mucin and Isc release was strongly inhibited by a 30 min preincubation with the classical K+ channel blockers quinine (1 mM), quinidine (1 mM), and Ba2+ (3 mM). Experiments with amphotericin B to measure separately the conductance changes of either luminal or basolateral plasma membrane revealed that quinidine did not directly block the ATP-induced basolateral K+ or the luminal anion channels. The quinidine inhibition after preincubation is therefore most easily explained by interference with granule fusion and location of anion channels in granule membranes. Luminal P2 receptors may play a role in intestinal defense mechanisms with both fluid and mucin secretion aiding in the removal of noxious agents from the mucosal surface.

Effects of cocaine on P3B in cocaine abusers

Little is known about the effects of cocaine on cognitive tasks. Event-related potentials (ERP) were recorded in 7 cocaine abusers during the performance of the auditory oddball task before and after the intravenous injections of saline and cocaine (60-80 mg). The P3B and slow wave components of the ERP were significantly larger 60-210 min after the cocaine than after the placebo injection. The results suggest that cocaine abusers have difficulty in maintaining optimal stimulus processing during extended testing. Cocaine blocks this decrement in stimulus processing.

[A retrospective analysis of continuous cervical epidural block]

This article reviews 763 patients who underwent continuous cervical epidural block (CCEB) in our hospital during the past ten years. We analyzed the factors causing complications of CCEB and the respiratory and hemodynamic inhibition caused by different concentrations of local anesthetics. From the study, it is concluded that CCEB has obvious advantages, such as mild respiratory and hemodynamic inhibition, satisfactory analgesia, no air pollution and low cost. On the other hand, CCEB requires highly skilled manipulation during epidural puncture and catheterization, careful intraoperative management and appropriate local anesthetics. The question of how to eliminate the intraoperative traction reaction needs further study.

Inhibition of hepatocyte gap junctional communication by 25-hydroxycholesterol may be mediated through free radicals

25-Hydroxycholesterol, an autoxidation product of cholesterol, has been shown to inhibit gap junctional communication between rat hepatocytes. In this study, we investigated whether free radicals are responsible for the effect of 25-hydroxycholesterol on hepatocytes. Addition of superoxide dismutase, hydroxyl radical scavenger mannitol, or the antioxidants diphenylphenylenediamine and alpha-tocopherol markedly decreased the inhibitory effect of 25-hydroxycholesterol. However, addition of catalase or the catalase inhibitor aminotriazole did not influence the inhibition of gap junctional communication by 25-hydroxycholesterol. Data from this study suggest that free radicals other than hydrogen peroxide are involved in the mechanism of 25-hydroxycholesterol-induced inhibition of gap junctional communication.

Treatment of strain of the infrapatellar fat pad by manipulation--observation of therapeutic effect in 117 cases

The present group comprises 117 cases of strain of the infrapatellar fat pad. The treatment effected a 100% cure in the mild and moderate types of the cases. In the severe cases suffering from such accompanying conditions as traumatic arthritis, the rate of effectiveness reached 100%, with all symptoms and signs becoming markedly alleviated. The treatment is considered a method of the first choice in handling strain of the infrapatellar fat pad, and also a good method for treating traumatic arthritis of the knee and malacia of the patella.

Osteopontin: a protein with diverse functions

In this review most of the various known, suspected, or postulated functions of osteopontin, a secreted highly acidic phosphoprotein, are discussed in terms of what we currently know about the protein. These include 1) binding of OPN both to cells via a GRGDS cell adhesion sequence that recognizes the alpha v beta 3 integrin and to extracellular matrix components via poorly characterized motifs, 2) regulation of the formation and remodeling of mineralized tissue, 3) recruiting and stimulating macrophages and lymphocytes as part of a nonspecific response to microbial infections, 4) multiple interactions with Ca2+ that likely influence OPN protein conformation and may be important in Ca(2+)-mediated or Ca(2+)-dependent processes, 5) inhibiting the growth of calcium oxalate crystals by disruption of the growing crystal lattice, 6) effects on gene expression, Ca2+ regulation, and nitric oxide production, and 7) involvement in cell migration. OPN production is frequently augmented when cell signaling pathways are activated by any of a variety of stimuli, for example in cancer cells.

Salmonella typhimurium neuraminidase acts with inversion of configuration

When the time course of the hydrolysis of identical solutions of p-nitrophenyl N-acetyl-alpha-D-neuraminide by Salmonella typhimurium neuraminidase is monitored by u.v. and by its optical rotation, the rotation change is synchronous with, or even marginally in advance of, the absorbance change. In experiments under the same conditions with influenza-virus neuraminidase, known to react with retention of configuration [Chong, Pegg, Taylor and von Itzstein (1992) Eur. J. Biochem. 207, 335-343], the rotation change is much slower than the absorbance change. The inverting, presumably single-displacement, mode of action of the S. typhimurium enzyme follows from these observations, and the position (92.5% beta) of the slowly established mutarotational equilibrium of N-acetylneuraminic acid [Friebolin, Kunzelmann, Supp, Brossmer, Keilich and Ziegler (1981) Tetrahedron Lett. 22, 1383-1386].

Production of cytokines and PGE2 and cytotoxicity of stimulated bone marrow macrophages after thermal injury and cytotoxicity of stimulated U-937 macrophages

Bone marrow-derived macrophages from normal and burned rats were cultured for one and four days in the presence of LPS, PHA, or opsonized zymosan as activators, and the supernatants were assayed for the inflammatory mediators TNF, IL-6, and PGE2 and the cells assayed for cytotoxicity. The macrophages responded differently to the various stimuli regarding cytotoxicity and the production of mediators, perhaps implicating the complement receptor CR1 in TNF production and the LPS receptor CD14 or the PHA lectin receptor in IL-6 and PGE2 production and for cytotoxicity. The response of the cells also depended on culture time and postburn time; in addition, macrophages from burned and unburned animals responded differently, depending on postburn day and the type of stimulus. TNF production was generally higher for one-day compared to four-day cultures (i.e., TNF was disappearing in the cultures), but IL-6 and PGE2 production was greater in four-day cultures. The results of this study suggest that thermal injury can contribute to the development of inflammatory and cytotoxic macrophages from bone marrow progenitor cells.

A kinetic-isotope-effect study of catalysis by Vibrio cholerae neuraminidase

Michaelis-Menten parameters for hydrolysis of seven aryl N-acetyl alpha-D-neuraminides by Vibrio cholerae neuraminidase at pH 5.0 correlate well with the leaving-group pKa (delta pK 3.0; beta 1g (V/K) = -0.73, r = -0.93; beta 1g (V) = -0.25; r = -0.95). The beta-deuterium kinetic-isotope effect, beta D2(V), for the p-nitrophenyl glycoside is the same at the optimum pH of 5.0 (1.059 +/- 0.010) as at pH 8.0 (1.053 +/- 0.010), suggesting that isotope effects are fully expressed with this substrate at the optimum pH. For this substrate at pH 5.0, leaving group 18O effects are 18(V) = 1.040 +/- 0.016 and 18(V/K) = 1.046 +/- 0.015, and individual secondary deuterium effects are beta proRD(V) = 1.037 +/- 0.014, beta proSD(V) = 1.018 +/- 0.015, beta proRD(V/K) = 1.030 +/- 0.017, beta proSD(V/K) = 1.030 +/- 0.017. All isotope effects, and the beta 1g(V/K) value are in accord with the first chemical step being both the first irreversible and the rate-determining step in enzyme turnover, with a transition state in which there is little proton donation to the leaving group, the C-O bond is largely cleaved, there is significant nucleophilic participation, and the sugar ring is in a conformation derived from the ground-state 2C5 chair. The apparent conflict between the beta 1g (V) value of -0.25 with all the kinetic-isotope-effect data can be resolved by the postulation of an interaction between the pi system of the aglycone ring and an anionic or nucleophilic group on the enzyme.

[Effect of yin and qi tonifying herbs on hyperthyroid model of yin-deficient rats]

The article reports the effect of Yin and Qi tonifying herbs (Radix Rehmanniae, Radix Ophiopogonis and Pseudostellaria Heterophylla) on hyperthyroid model of Yin-deficient rats. The model rats were made Yin-deficient by injecting thyroxine. Observation showed that after injection, indexes such as anus temperature, oxygen consumption, weight, diet, activity, general conditions, triiodothyronine (T3) and thyroxine (T4) in serum were markedly changed. It is thus suggested that the Yin and Qi tonifying mixture of the above three herbs can regulate and correct Yin-deficiency in hyperthyroid model of Yin-deficient rats.

Oxysterols inhibit gap junctional communication between rat hepatocytes in primary culture

Several oxysterols were examined for their effect on gap junctional communication between rat hepatocytes in primary culture. 25-Hydroxycholesterol, 22(S)-hydroxycholesterol and 7 beta-hydroxycholesterol, in decreasing order of potency, markedly inhibited gap junctional communication. In contrast, 7-ketocholesterol showed no inhibitory effect. The inhibition of gap junctional communication by oxysterols was not a consequence of changes in cell viability, as measured by lactate dehydrogenase leakage and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction activity. The addition of exogenous cholesterol to the culture medium did not abolish the effect of 25-hydroxycholesterol, suggesting that the capacity of oxysterols to inhibit gap junctional communication is independent of their inhibitory effect on cholesterol synthesis. We suppose that inhibition of gap junctional communication may be an early sign of oxysterols-induced toxicity on hepatocytes.

The nutrition transition in China: a cross-sectional analysis

Diets and activity patterns are changing rapidly in low-income countries, and problems of undernutrition and overnutrition commonly exist side by side. China has conquered problems of food scarcity at the national level and has undergone a remarkable transition in the structure of its diet in the last decade. In this paper, we use data from the 1989 China Health and Nutrition Survey and national data from the State Statistical Bureau to explore China's recent history with respect to nutrition and to identify patterns of under- and overnutrition. In particular, we see that higher income levels, particularly in urban areas, are associated with consumption of a diet higher in fat and with problems of obesity. At the same time, undernutrition is a problem in important segments of Chinese society. There is a need for the Chinese government to consider ways to address these problems of deficit and excess jointly.

BIBW 22, a dipyridamole analogue, acts as a bifunctional modulator on tumor cells by influencing both P-glycoprotein and nucleoside transport

BIBW 22, a phenylpteridine analogue of dipyridamole (DPM), enhanced vincristine cytotoxicity approximately 10 times more than DPM in a multidrug-resistant (MDR) KB V20C cell line. Using rhodamine 123 accumulation in KB V20C cells as an indicator of MDR phenotype, BIBW 22 was shown to be about 100 times more potent than DPM in inhibiting the MDR-associated efflux of rhodamine 123. Photolabeling of P-glycoprotein in KB V20C plasma membranes with 0.2 microM [3H]azidopine was strongly inhibited by 1 microM BIBW 22, indicating that this compound reverses the MDR phenotype by interfering with MDR-associated P-glycoprotein. In addition, BIBW 22 at 1 microM could also enhance the cytotoxicity of 5-fluorouracil in KB cells about 20-fold. Its potency in inhibiting nucleoside transport is 7-fold more potent than that of DPM. These results suggest that BIBW 22 is a potent bifunctional modulator which influences both P-glycoprotein and nucleoside transport in tumor cells. Potential use of this compound as a modulator of combination chemotherapy involving antimetabolites and drugs affected by MDR should be explored.

[The precursors and effectors of human lymphokine-activated killer (LAK) cells]

Natural killer cells were enriched in the second fraction (F2) of discontinuous Percoll density gradients from human PBL after centrifugation, whereas T lymphocytes were enriched in F4. The cytotoxicity against K562 by F2 LAK (F2 cells activated by rIL2) was higher than that of F2 cells. F2 LAK also acquired the ability to lyse NK-resistant tumor cell lines and noncultured lung cancer cells (6 out of 9 cases). All these activities of F2 LAK cells were significantly higher than those of F4 LAK cells. Besides, F2 LAK exhibited higher level of lysis against noncultured lung cancer cells than did LAK derived from PBL. Enzyme-labeled immunocytochemistry staining showed that the number of CD16+ and CD8+ cells in F2 was much more than that in F4. So the higher lytic ability of F2 LAK might come from two kinds of precursors: CD16+ typical NK cells and MHC unrestricted CD8+, NK-like' cytotoxic T lymphocytes. The number of CD4+ cells in F4 was much more than that in F2. They shouldn't be the precursors of LAK cells, otherwise the lytic ability of F4 LAK should be higher than that of F2 LAK. After being cultured with rIL2 for 3 days, F2 cells exhibited proliferative response. But the percentage of CD16+ and CD8+ cells in F2 LAK did not change much, and remained much higher than that in F4 LAK. So the effector cells of short-term cultured LAK might be the activated CD16+ NK cells and CD8+, NK-like' cytotoxic T lymphocytes as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitumor agents. 126. Novel 4 beta-substituted anilino derivatives of 3',4'-O,O-didemethylpodophyllotoxin as potent inhibitors of human DNA topoisomerase II

A series of derivatives of 3',4'-O,O-didemethylpodophyllotoxin have been synthesized and evaluated for their inhibitor activity against neoplastic cell growth (KB) and against human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results show that the compounds possessing a 4 beta-anilino moiety either unsubstituted or substituted at the para (F, COOCH3, COCH3, CN, CH2CN, NO2) or meta (OH) positions or with an ethylenedioxy moiety showed the same or greater activity than etoposide in causing cellular protein-linked DNA breakage and in inhibiting DNA topoisomerase II. However, compared to the corresponding 4'-O-demethyl analogues, the 3',4'-O,O-didemethyl compounds have a similar potency in inhibition of DNA topoisomerase II but are less active in causing cellular protein-linked DNA breakage. Complete correlation between the three biological activities--cytotoxicity, inhibition of DNA topoisomerase II, and induction of protein-linked DNA breakage--was also not observed. This supports the possibility that the biological determinants of action among these compounds may be different.