Vasodilative properties of BPDZ 79, a new potassium channel opener, in isolated aorta

AIM

To compare the effect of a novel potassium channel opener 3-(1',2',2'-trimethylpropyl)amine-4H-pyrido (2,3-e)-1,2,4-thiadiazine, 1-dioxide (BPDZ 79), with diazoxide on aorta.

METHODS

Muscle tension of rat aorta was compared with adjacent aortic rings without endothelium. One ring was precontracted with KCl 80 mmol.L-1. Three rings were precontracted with KCl 80 mmol.L-1, and two of them were incubated with glibenclamide (0, 1, and 10 mumol.L-1). 86Rb outflow from rat aorta was measured in the presence of glibenclamide 10 mumol.L-1.

RESULTS

BPDZ 79 and diazoxide provoked concentration-dependent and endothelium-independent relaxation of the vasoconstriction evoked by KCl 30 mmol.L-1, but not by 80 mmol.L-1. BPDZ 79 showed more potent vasorelaxation and 86Rb outflow than diazoxide. After incubation with glibenclamide (1 and 10 mumol.L-1), an inhibitor of the ATP-sensitive K+ channels, the relaxation induced by BPDZ 79 and diazoxide were decreased with the same pattern.

CONCLUSION

BPDZ 79 is a potent vasodilator by opening potassium channels.

Prevention by selenium supplementation of cyclosporin-A-induced vascular toxicity

OBJECTIVE

The aim was to determine whether selenium supplementation, an important component of glutathione peroxidase, might attenuate cyclosporin (Cx)-induced vascular toxicity.

METHODS

Four groups of rats were treated in parallel: the first group was supplemented with selenium (sodium selenite, 0.5 mg.kg-1) orally (p.o.) for 5 weeks and the same dose of selenium plus Cx 20 mg.kg-1 (i.m.) during the 6th week; group 2 received Cx only (20 mg.kg-1 i.m. for 1 week); group 3 was supplemented with selenium (0.5 mg.kg-1 p.o., for 6 weeks) and group 4 served as control. Thoracic aortas isolated from these various groups were studied in organ baths.

RESULTS

In comparison with the control group, selenium supplementation did not modify acetylcholine (Ach)- and nitroprusside-induced relaxations. In group 2, endothelium-dependent relaxations (Ach) were markedly impaired and endothelium-independent relaxations (nitroprusside) were shifted to the right; with selenium supplementation (group 1), the responses to Ach were partially restored whereas the rightward shift of the concentration-response curves to nitroprusside persisted. Incubation with superoxide dismutase (SOD, 150 IU.ml-1) or selenium (1 microgram.ml-1) (but not with selenium plus an inhibitor of the glutathione redox cycle) improved the relaxations to Ach in group 2.

CONCLUSIONS

The vascular toxicity of Cx seems related to generation of oxygen-derived radicals promoting EDRF destruction and is attenuated by selenium supplementation.

Genetic variation in the VP7 gene of human rotavirus serotype 3 (G3 type) isolated in China and Japan

Sequence analysis of the VP7 gene was performed on twenty-one human isolates of serotype 3 related-rotavirus in China and Japan. The five Chinese isolates were found to be not similar to the 16 Japanese isolates and to SA11 (simian rotavirus). The Chinese isolates, especially CHW2 and CH-32, were different from the major serotype 3 human isolates. AU-1 and 02/92 which previously showed a wider spacing between RNA segments 10 and 11 by RNA polyacrylamide gel electrophoretic analysis, were more closely related to each other and could be differentiated from the other Chinese and Japanese isolates. For these reasons, serotype 3 viruses were considered to be intraserotypically more heterologous than serotype 1, 2 and 4 viruses.

Endothelium-dependent effect of perindopril and enalaprilat in rat thoracic aorta

AIM

To study the effect of the angiotensin-converting enzyme (ACE) inhibitors perindopril (Per) and enalaprilat (Ena) on the reactivity of the endothelium in normal rats.

METHODS

Male rats were treated intragastrically with Per (2 mg.kg-1.d-1) or placebo (n = 18) for 6 wk. Aorta was isolated for experiment. Another set of isolated aortic rings with and without endothelium were incubated with Ena (0.1 mumol.L-1) for 30 min. Responses to acetylcholine, serotonin, phenylephrine, sodium nitroprusside (SN), and nitroglycerin (Nit) were observed.

RESULTS

Endothelium-dependent relaxation to acetylcholine was augmented in aortic rings from rats treated with Per in comparison with control. The IC50 value (95% confidence limits) decreased from 3.8 (0.56-26.1) mumol.L-1 (control group) to 0.98 (0.28-3.41) mumol.L-1 (Per-treated group). The maximal relaxation was augmented from 62 +/- 9% to 78 +/- 10% (P < 0.01). However, the responses to the endothelium-independent vasodilators, SN and Nit, were similar. Serotonin- and phenylephrine-induced contractions were decreased, which were influenced by basal release of endothelium-derived relaxing factor (EDRF). EC50 values was 6.1 (2.6-14.4) nmol.L-1 vs 8.3 (3.6-18.8) nmol.L-1 in comparison with control group and Per-treated group. The maximal contraction was decreased from 2.42 +/- 0.29 g (control group) to 1.96 +/- 0.25 g (treated group) (P < 0.01). Similar results were found in incubation with Ena.

CONCLUSION

Ena and Per enhanced the basic release of EDRF from vascular endothelium.

Sequence conservation and expression of the gene encoding the outer capsid glycoprotein among human group C rotaviruses of global distribution

Group C rotaviruses have been identified recently from fecal samples of children with diarrhea in the United States. Using reverse transcriptasepolymerase chain reaction and sequence analysis, we sequenced gene 8s encoding VP7 from two U.S. strains (RI-1 and RI-2), and eight other strains isolated from patients on four continents, and compared these with the sequences of four published strains. The gene 8s of the 14 strains were remarkably conserved in size and in predicted primary and secondary structures. When the sequences of the human VP7s were compared with that of the prototype porcine Cowden strain, six regions were found variable in both deduced primary and predicted secondary structures, four of which were predicted to be hydrophilic and might determine serotype specificity. Gene 8 of the human S-1 strain was further characterized by expression in recombinant baculoviruses. The expressed product was immunogenic but failed to elicit neutralizing antibodies. Our sequence analysis indicates that all the human strains characterized to date belong to a single G genotype, which may constitute a single G serotype, pending further antigenic analysis. Whether the human strains and the Cowden strain are the same serotype remains to be determined.

Genetic variation in VP7 gene of human rotavirus serotype 2 (G2 type) isolated in Japan, China, and Pakistan

Sequence analysis of the gene encoding the major neutralization glycoprotein (VP7) was performed on sixteen human isolates of serotype 2 of rotavirus in Japan, China, and Pakistan and their genetic variations were examined. Comparative studies of their nucleotide and deduced amino acid sequences between the sixteen isolates and the HU5 strain revealed an overall homology of more than 94%. A higher degree of homology in nucleotides was observed among the sixteen isolates than between HU5 and the isolates. A total of thirteen amino acid residues frequently converted to another amino acid. Out of the thirteen, five amino acid residues belonging to the major neutralizing epitope regions (C, E, and F in this communication) converted frequently. From the amino acid sequences three subtypes, subtype 1, subtype 2, and intermediate, were suggested to be classified as previously reported for serotype 1 (Xin et al, Virology, 1993, 197: 813-816).

Serum antibody response to recombinant major inner capsid protein following human infection with group B rotavirus

Recombinant major inner capsid protein (VP6) of the IDIR strain of group B rotavirus (GBR) was incorporated in a solid-phase immunoassay to access antibody response to infection in humans. Expression of VP6 in insect cells permitted design of a highly sensitive assay that avoided the contaminants present in GBR antigens obtained from fecal specimens. Among patients infected with the ADRV strain of GBR in China, increased reactivity with recombinant VP6 was observed in convalescent-phase sera in comparison with sera obtained shortly after infection (P = 0.0084). Anti-VP6 antibodies were detectable as soon as 7 days after onset of gastrointestinal symptoms, and serum reactivity persisted in specimens drawn more than 1 year after infection. Solid-phase immunoassay with recombinant VP6 was next employed in order to assess anti-GBR antibody in 513 serum specimens obtained from 423 Maryland residents (ages, 7 months to 96 years; median age, 42 years). Four individuals (< 1%) exhibited serum antibodies directed against the recombinant VP6 (ages, 54 to 95 years; mean age, 77 years). Examination of 129 additional serum specimens including some from other geographic regions of the United States failed to reveal the presence of anti-GBR antibody. Anti-GBR antibody was also not detected in any of 131 serum specimens from 60 staff and residents of a nursing home in Switzerland. While infection of humans with GBR has been uncommon in these locations outside of China, the detection of serum antibodies in older individuals in the United States either indicated an unknown, age-related risk factor or may have indicated infection in the more distant past. The availability of these reagents should allow surveys for GBR infection among additional populations that have not previously been investigated.

Genetic variation in VP7 gene of human rotavirus serotype 1 (G1 type) isolated in Japan and China

Sequence analysis of the gene encoding the major neutralization glycoprotein (VP7) was performed on 12 human isolates of serotype 1 of rotavirus in Japan and China. They were examined for genetic variations among serotype 1 isolates. Comparative studies of their nucleotide and deduced amino acid sequences between the 12 isolates and the Wa strain revealed an overall homology of more than 92 and 96%, respectively. Higher degrees of homologies were observed between Wa and 2 strains (K1 and K2) in Tokyo, 1979-1980, than between Wa and recent isolated strains in Tokyo and in China. In our isolates, a total of 16 amino acid residues frequently converted to another amino acid. Six amino acid residues belonging to the major neutralizing epitope regions (B, D, and E in this communication) frequently converted. From these data three subtypes (subtypes A, B, and intermediate) were suggested to be divided. Whether these differences are an important mechanism in the epidemiology of rotaviruses requires further investigation.

Distribution of wild type 1 poliovirus genotypes in China

Poliomyelitis remains an important public health problem in China. Most cases and outbreaks are associated with wild type 1 polioviruses. To obtain an overview of type 1 poliovirus transmission in China, partial genomic sequences were compared for 24 case isolates from 12 provinces. Because polioviruses evolve rapidly during infection of humans, the genetic relationships among isolates provide a measure of the extent of epidemiologic linkage among cases. The observed genetic relationships were complex: six different genotypes, apparently derived from five separate endemic origins, were found. One genotype was recombinant, having noncapsid sequences derived from the Sabin type 1 vaccine strain and capsid sequences derived from a genotype indigenous to several northern and eastern provinces. Some isolates from geographically separate provinces were closely related; other isolates were related to wild polioviruses found in neighboring countries. The combination of epidemiologic and virologic analyses may facilitate the development of more effective strategies for poliomyelitis eradication.

[Diagnosis of breast cancer by computed infrared light scan]

One hundred and eleven patients with various pathologically proved breast diseases were examined by computed infrared light scan (ILS). The results were compared with those of palpation and X-ray mammography. The correct rate in 50 cancers was 90%, significantly superior to that of X-ray (70%, P less than 0.05). The lower diagnostic rate of X-ray may have been due to higher percentage of younger patients (30-40 years of age) who had higher density in the breast in this group. The criteria of diagnosis of cancers by ILS on the video monitor were: 1. The shadow of the mass- the lower grade of gray-shade implied the possibility of malignancy, and 2. Pattern of the blood vessels around the mass-increase in number, diameter, distortion, a zigzag course or disappearance of blood vasculature suggested malignancy. ILS is considered simple, non-invasive, easy to operate and reliable in the detection of breast cancers.

Mechanical and ionic response of rat aorta to diazoxide

Diazoxide provoked concentration-dependent and endothelium-independent relaxations of the mechanical responses evoked by low concentrations of KCl. Glibenclamide, tolbutamide and tetraethylammonium shifted the concentration-response curve for diazoxide to the right. The drug also caused a dose-dependent stimulation of 86Rb outflow which was inhibited by glibenclamide and tolbutamide. Diazoxide (10(-4) and 10(-3) M) inhibited the contractions elicited by 10(-1) M K+ and provoked a concentration-dependent reduction in the contractile responses to Ca2+. Diazoxide also reduced the KCl (8 x 10(-2) M)-induced increase in 45Ca outflow. These data indicate that the vasorelaxant properties of diazoxide are probably related to an inhibition of Ca2+ entry into smooth muscle cells. The reduction in Ca2+ entry appears to result from K+ channel activation. At high concentrations, diazoxide also exhibited antagonistic actions on voltage-sensitive Ca2+ channels.

Coding assignments of the genome of adult diarrhea rotavirus

Adult diarrhea rotavirus (ADRV) has caused epidemics of diarrhea in China since 1982 and remains the only group B rotavirus associated with widespread disease in humans. We recently characterized the proteins of ADRV and have now proceeded to identify the gene segments encoding each protein. Viral RNA transcripts were synthesized in vitro with the endogenous viral RNA polymerase and separated by electrophoresis in agarose. The individual transcripts were translated in a cell-free system using nuclease-treated rabbit reticulocyte lysates. The translation products were compared with polypeptides found in purified virus and were characterized by SDS-PAGE, immunoprecipitation, and Western blot analysis using antisera to double- and single-shelled virions, virus cores, and monoclonal antibodies. Furthermore, individual RNA transcripts were hybridized to total dsRNA to determine their genomic origin. Based on this analysis, the core polypeptides VP1, VP2 and VP3 are encoded by segments 1, 2, and 3, respectively. The main polypeptides in the inner capsid, VP6, and the outer capsid, VP4 and VP7, are encoded by segments 6, 4, and 8 respectively. Segments 5, 7, and 9 code for 60, 45, and 30 kDa nonstructural polypeptides. Two other nonstructural polypeptides (24 and 25 kDa) are derived from gene segment 11. Gene segment 10 codes for a 26 kDa polypeptide that is precipitated with serum to ADRV and may be a structural protein VP9. With this exception, gene coding assignments of ADRV are comparable to those of the group A rotaviruses. Our results have clear implications for further work in cloning, sequencing, and expression genes of ADRV and can provide direction towards understanding the origin and the evolution of this virus.

Intravenous diltiazem versus nitroglycerin for silent and symptomatic myocardial ischemia in unstable angina pectoris

For 18 patients consecutively admitted to the coronary care unit for unstable angina, 48-hour electrocardiographic Holter monitoring was performed after they were randomly assigned in a single-blind fashion to 1 of 2 treatment groups. The first group was treated with acetylsalicylic acid (ASA) and intravenous nitroglycerin, the second with ASA and intravenous diltiazem. All of the patients treated with nitroglycerin still had ischemic episodes after 48 hours (33% were symptomatic), in contrast with 11% of the diltiazem group (11% asymptomatic). Maximal ST-segment depressions of symptomatic and asymptomatic episodes were significantly different; and no significant increases in heart rate were observed either during the 15 seconds before ischemia began or during the ischemic episode. During the 48 hours, the diltiazem group had significantly fewer ischemic episodes (17) than did the nitroglycerin group (145). We concluded that "on-line" ST-segment observation is of prime importance for monitoring unstable angina; that the majority of the ischemic episodes associated with unstable angina are silent; and that intravenous diltiazem could be an effective pretreatment for patients who must undergo mechanical or surgical therapy.

Prevention of cyclosporine A-induced vascular toxicity by pentoxifylline

To determine whether an in vivo treatment with pentoxifylline (PTX) can prevent the vascular toxicity of cyclosporine A (Cx), three groups of rats were studied in parallel. The first group received daily injections of Cx (20 mg/kg intramuscularly) and pentoxifylline (80 mg/kg intraperitoneally) for 7 days, the second group was treated with Cx only, and the third group served as control (vehicle treatment). Cx serum levels were similar in groups 1 and 2. In thoracic aortic rings isolated from Cx group (group 2), the concentration-response curves to phenylephrine were potentiated: there was a significant leftward shift (p less than 0.001 vs. control) in the EC50 values and an increase in the maximal responses (p less than 0.05). After mechanical removal of the endothelium or inhibition of endothelium-derived relaxing factor formation (incubation with NG-monomethyl-L-arginine, L-NMMA), this enhanced responsiveness to phenylephrine persisted. In preparations from the same group (group 2), the endothelium-dependent relaxations to acetylcholine (ACh) were decreased whereas the endothelium-independent relaxations to nitroprusside (NTP 0.01-10 nM) and forskolin (1 nM) were slightly attenuated but without changes in the maximal response. In the group cotreated with Cx and PTX (group 1), the responses to ACh, NTP, and forskolin were not different from controls whereas the greater responsiveness to phenylephrine was only partially attenuated. In vivo cotreatment with PTX may prevent the endothelial dysfunction and the functional changes in smooth muscle cells induced by Cx.

Alterations of the endothelial function of isolated aortae in rats with adjuvant arthritis

Adjuvant arthritis was induced in 30 male Wistar rats by injection into the tail of heat-killed Mycobacterium butyricum. Three weeks later, 14 of these rats exhibited severe arthritic lesions. Their thoracic aortae were studied in parallel with those isolated from a control group. On rings precontracted with phenylephrine (0.1 microM), the endothelium-dependent relaxations produced by acetylcholine and histamine were significantly diminished in the arthritic group as compared to the control group. Moreover, the increase in tone induced by incubation with methylene blue (10 microM) (a nonspecific inhibitor of endothelium-derived relaxing factor) was significantly less pronounced in preparations isolated from the arthritic group. On the other hand, relaxations produced by the endothelium-independent vasodilators verapamil and nitroprusside were similar in both groups. It is concluded that adjuvant arthritis modifies the endothelium-derived relaxing factor-mediated responses of rat aorta.

Detection of group B and C rotaviruses by polymerase chain reaction

We adapted the polymerase chain reaction (PCR) to detect the noncultivatable group B and C rotaviruses and introduced a simple and convenient technique to purify viral RNA from stool specimens. Double-stranded RNA present in stool extracts was purified by adsorption to hydroxyapatite and was used as the template for reverse transcription and polymerase amplification. Primer pairs specific for group B (gene 8) and group C (gene 6) rotaviruses were selected to amplify group-characteristic sizes of cDNA copies readily identifiable in ethidium bromide-stained agarose gels. These primer pairs were used separately in individual PCR assays or were pooled with a primer pair specific for group A rotavirus (gene 9) in a combined PCR assay for the simultaneous detection of all three rotavirus groups. The method was very sensitive and was used to identify both human and porcine strains of group B and C rotaviruses in stool specimens. A second PCR amplification with internal group-specific primers served to increase further the sensitivity of the test and to confirm the diagnostic results obtained in the first amplification.

Endothelium-dependent effects of pentoxifylline in rat aorta

Experiments were performed with isolated rat aortas to study the vasoactive properties of pentoxifylline, a cyclic AMP phosphodiesterase inhibitor, which is used as a hemorheologic agent in the treatment of peripheral vascular disease. In rings precontracted with phenylephrine (0.1 microM), pentoxifylline (10 nM-10 microM) induced concentration-dependent relaxations which were not modified after incubation with indomethacin (3 microM) but which were almost completely abolished after incubation with methylene blue (10 microM) or after mechanical removal of the endothelium. After incubation with pentoxifylline (10 microM) for 30 min, the concentration-response curves for endothelium-dependent relaxations to acetylcholine were shifted to the left and the serotonin-induced contractions were decreased, while the relaxations to forskolin, which are endothelium-independent and cyclic AMP-mediated, were not altered. We conclude that pentoxifylline exerts vasoactive effects that are mediated by endothelium-derived relaxing factor (EDRF), and that pentoxifylline has negligible endothelium-independent vasodilating properties. These properties of inducing or potentiating EDRF-mediated effects might contribute to the efficacy of pentoxifylline in the treatment of vascular disease.

Effects of auranofin on endothelium dependent contractions in isolated rat aorta

Auranofin (10(-6) and 10(-5)M) reduces the acetylcholine induced relaxation in the isolated rat aorta. Contractions induced by phenylephrine and 5-hydroxytryptamine are enhanced by auranofin 10(-6)M only when endothelium is present. At higher concentration (10(-5)M), it antagonizes the agonist-induced contractions either in the presence or absence of endothelium.

Effects of in vivo SIN1 treatment on nitrovasodilator relaxation and on EDRF-mediated responses in rat aorta

SIN1 (the active metabolite of molsidomine), nitroglycerin, and endothelium-derived relaxing factor (EDRF) produce vasodilation by activation of soluble guanylate cyclase. Therefore, prolonged exposure to SIN1 might affect not only the responses to SIN1 itself and to nitroglycerin but also to EDRF. In vivo treatment of rats consisted of subcutaneous injections of either SIN1 (60 mg/kg) for the treated group or placebo for the control group, twice daily for 3 days. Thoracic aortas from the treated group were threefold and sixfold less sensitive to nitroglycerin and SIN1, respectively. The endothelium-dependent relaxations to acetylcholine were, nevertheless, similar in both groups. Moreover, the concentration-response curves to phenylephrine, which are known to be modulated by the endothelium, were similar in both groups. In addition, incubation with methylene blue (10 microM for 30 min), which blocks the vasodilator action of EDRF, potentiated in the same way the contractions to this alpha-adrenergic agonist. The increase in resting tone induced by methylene blue incubation was also equivalent in the two groups. The present results show that SIN1 treatment for several days in rats is associated with slight tolerance development not only to SIN1 itself but also to nitroglycerin, while the endothelial function remains operative. We conclude that the mechanisms involved in the activation of guanylate cyclase by SIN1 and nitroglycerin are probably different than those of EDRF-mediated responses.

Polymerase chain reaction amplification and typing of rotavirus nucleic acid from stool specimens

The rotavirus gene segment coding for the major outer capsid glycoprotein vp7 was amplified directly from stool specimens by the polymerase chain reaction (PCR). Double-stranded RNA extracted from stool samples was used as the template for reverse transcription, which was followed immediately and in the same reaction mix with amplification, using the Taq polymerase. Various conditions were examined to optimize the yield of the amplified gene. The concentrations of MgCl2, dimethyl sulfoxide, and template RNA were critical. The choice of primer pairs allowed amplification of the entire segment or specific portions. By using type-specific primers derived from distinct regions on the gene, we devised a PCR typing method in which each human serotype virus produced a characteristic segment size, readily identifiable in agarose gels. The PCR typing method was applied to 10 rotavirus reference strains, including all 6 known human serotypes (serotypes 1, 2, 3, 4, 8, and 9), and to 34 stool specimens previously serotyped by an enzyme immunoassay with monoclonal antibodies. An absolute correlation was found between the molecular and serologic methods. In addition, 14 stool specimens nonserotypable by an enzyme immunoassay with monoclonal antibodies could be typed by the PCR method. Besides the application for rotavirus detection and typing directly from stools, the PCR method provides a rapid and efficient means of obtaining large quantities of cDNA suitable for sequencing, cloning, and other genetic studies, precluding the need for cell culture and virus purification.

Hypoglycemic sulfonylureas antagonize the effects of cromakalim and pinacidil on 86Rb fluxes and contractile activity in the rat aorta

Cromakalim, pinacidil and nitroprusside provoked concentration-dependent relaxations of K(+)-depolarized rat aortae. Glibenclamide, tolbutamide and to a lesser extent tetraethylammonium antagonized the vasorelaxant action of cromakalim and pinacidil. Cromakalim, pinacidil but not nitroprusside elicited a marked increase in 86Rb outflow from preloaded and perifused aortic rings. These increases in 86Rb outflow were inhibited in a concentration-dependent manner by glibenclamide and tetraethylammonium. Our data extend previous observations indicating the involvement of K+ channels in the vasorelaxant properties of cromakalim and pinacidil. Moreover, the present findings suggest that both compounds could interfere with a vascular type of ATP-sensitive K+ channels.

Investigation of an outbreak of adult diarrhea rotavirus in China

In 1987 an epidemic of diarrhea associated with adult diarrhea rotavirus (ADRV) occurred in Qinhuangdao City, China, affecting more than 200 persons and causing 2 deaths. The outbreak was introduced by a person returning from an epidemic area and was spread initially to his family members and subsequently to the entire community. Adults were at greater risk of diarrhea than children 0-4 y of age and, the duration of illness increased significantly with increasing age. ADRV was identified by ELISA and electron microscopy. The electropherotypes of all positive specimens were identical, consistent with the single point-source introduction of the virus. Seroconversion was detected in 6 of 7 ill persons with a blocking ELISA. Both asymptomatic infection and person-to-person spread identified in this epidemic suggest that current emphasis on preventing waterborne transmission may not control the introduction of ADRV into new areas. The predisposition of adults for more severe disease with ADRV is similar to the pattern observed with other enteric viruses such as the Norwalk agent and hepatitis A.

Seroepidemiology of adult diarrhea rotavirus in China, 1977 to 1987

In 1982, large outbreaks of diarrhea that were caused by group B adult diarrhea rotavirus (ADRV) occurred throughout the People's Republic of China. Until 1982, group B rotavirus had never been associated with disease in humans. To determine whether ADRV was a new virus introduced in 1982 or had been present before that time, we examined antibody titers of ADRV in gamma globulin (pooled immunoglobulin) pools that were prepared during 1977 to 1987 in four cities in the People's Republic of China (Shanghai, Lanzhou, Wuhan, and Chandu). ADRV antibodies were assayed by using a blocking enzyme-linked immunosorbent assay. Antibodies were present in most Chinese gamma globulins tested, including those collected in Shanghai before the 1982 epidemic, and absent from American reference pools. The highest titers of antibody to ADRV (3,200) were found in gamma globulins collected in 1983 in Shanghai just after the epidemic, and these were fourfold higher than titers present in the preceding years. The quality of the gamma globulins stored for up to 12 years was tested by measuring levels of immunoglobulin G to group A rotavirus; these were equally high in gamma globulin pools prepared in the United States and in all samples from the People's Republic of China. Serum samples from patients from an outbreak of ADRV had elevated titers to ADRV 3 and 16 months after the onset of symptoms. These findings, as well as other epidemiologic findings on ADRV, suggest that the organism is an important and continuing cause of diarrhea in the People's Republic of China, was present before the first epidemic in 1982, and represents a risk to surrounding populations in Asia.

Comparison of responses to acetylcholine and serotonin on isolated canine and human coronary arteries

Canine and human coronary arteries were studied in organ baths to compare the responses to acetylcholine and serotonin in the two species. The human coronary rings were isolated from seven patients without cardiac disease (mean age 15 years, range 7-20). In one set of experiments canine and human preparations were incubated with phentolamine, propranolol and ketanserin (all at 1 mumol.litre-1 concentration) and precontracted with prostaglandin F2 alpha (PGF2 alpha 1-2 mumol.litre-1). Acetylcholine (0.1-10 mumol.litre-1) and serotonin (0.1-100 mumol.litre-1) relaxed canine preparations dose dependently, the maximum responses (expressed as % of depression of PGF2 alpha response) being 84 (SEM 6)% (n = 9) and 51(5)% (n = 6) respectively. In the same experimental conditions, acetylcholine and serotonin failed to relax the human coronary rings (n = 11) while substance P and bradykinin induced relaxations of 72(4)% (n = 11) and 66(7)% (n = 11) of PGF2 alpha response respectively. In another set of experiments, dose-contraction curves were constructed for acetylcholine or serotonin (in presence of phentolamine and propranolol). On human rings with endothelium, methylene blue (10 mumol.litre-1), a non-specific inhibitor of endothelium derived relaxing factor (EDRF), potentiated these dose-contraction curves: markedly for serotonin, the EC50 decreasing from 1.2(0.2) to 0.22(0.08) mumol.litre-1 (n = 11, p less than 0.01) with a significant increase in the maximal response); and slightly for acetylcholine, EC50 decreasing from 0.84(0.11) to 0.40(0.13) mumol.litre-1 (n = 10, p less than 0.05) without significant change in the maximal response.(ABSTRACT TRUNCATED AT 250 WORDS)