Emphysema surgery--loop ligation approach

OBJECTIVES

To demonstrate the efficacy of using thoracoscopic endoloop ligation of bullae in patients with bullous emphysema.

METHODS

From 1992 to 1997, 93 advanced age (mean age, 66 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Thoracoscopic loop ligation of bulla was carried out under general anesthesia with double lumen endotracheal tube and single lung ventilation.

RESULTS

Eighty-two patients (88%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 7.5 days (range, 4-19 days). Average hospital stay was 9.5 (range, 5-26) days. There was no post-operative death. A comparison of pre-operative and post-operative functional evaluation was available in 27 patients who showed an average increase in FEV1 (from 0.89 to 1.12 l) and declined in residual volume after operation. Complications include persistent airleak over 10 days in nine patients (9.7%), wound infection in three patients and localized empyema in five patients. There was no recurrent after a mean follow-up of 37 months.

CONCLUSION

Thoracoscopic loop ligation of bulla has proven to be a safe, reliable and cost effective means of technique for bullous emphysema.

Two new alkaloids from artabotrys uncinatus

A novel oxazoloaporphine, artabonatine A (1), and a new 7-hydroxyaporphine, artabonatine B (2), have been isolated and characterized from the fresh unripe fruits of Artabotrys uncinatus, along with five known compounds. Structure elucidation of 1 and 2 was based on UV, IR, NMR, and MS analyses.

Leiomyosarcoma of the gastric cardia and fundus

BACKGROUND

Gastric leiomyosarcoma is rare among gastric malignancies, and only 20% of the cases are located in the gastric cardia or fundus. It has clinical manifestations different from tumors in other sites of the stomach. We reviewed cases of leiomyosarcoma of the gastric cardia or fundus to evaluate their clinicopathologic characters and patient survival.

METHODS

From May, 1981, to June, 1998, a total of 15 patients who underwent curative resection of leiomyosarcoma of the gastric cardia or fundus were retrospectively identified and studied. All the clinical and pathologic data were reviewed and recorded.

RESULTS

There were 11 men and four women. Their mean age was 59.1 years (range, 37-73 years). Tarry stools and epigastric fullness and pain were the most common symptoms, followed by body weight loss. All 15 patients had submucosal tumors in the gastric cardia or fundus, as shown by endoscopy, barium contrast radiography and computerized tomography. The incidence of esophageal involvement by the tumors was quite low. The mean tumor size was 10 cm, ranging from 4 cm to 20 cm. Locoregional organs were involved in nine patients. The median and mean survivals were 17.8 months and 31.7 months, respectively (range, 10.1-80.1 months) after curative resection. The three-year and five-year survival rates were 53% and 22%, respectively.

CONCLUSIONS

The definitive preoperative diagnosis of the tumor is difficult before surgery, even though imaging studies show positive findings. Surgical resection with an adequate safe margin of normal tissue is the treatment of choice. Tumor size, serosal invasion with locoregional organ involvement and high tumor grade were the prognostic factors in the study.

The epidemiology of Japanese encephalitis on Taiwan during 1966-1997

Japanese encephalitis (JE) is an endemic disease in Taiwan. A mass vaccination program of children against JE was first implemented in 1968. Along with general improvements in various aspects of living conditions over the years, the program has brought JE well under control. The main characteristics of JE epidemiology in Taiwan in the past 3 decades are as follows. The transmission mode remains unchanged-that is, the amplification stage of the virus in pigs is followed by a human epidemic each year. The frequency of JE incidence has dropped significantly. The incidence rate of confirmed cases was 2.05 per 100,000 in 1967, the highest in record, and merely 0.03 per 100,000 in 1997. Confirmed cases occur sporadically all over the island. The peak of the epidemic season has shifted from August in the 1960s to June since the 1980s. The age distribution of confirmed cases has shifted gradually from mainly children to adults. Vaccine efficacy for those having received more than 2 doses of the vaccine is estimated to be about 85%.

Aromin-A, an Annonaceous acetogenin from Annona cherimola

Chromatographic fractionation of a MeOH extract from the stems of Annona cherimola led to the isolation of a new non-adjacent, bis-THF ring acetogenin (one THF ring being at C-4 and the other at C-16), aromin-A (1) along with the known cytotoxic acetogenin squamocin (2). The structures of these isolates were established by means of mass spectrometry and spectroscopic techniques.

Post mass-immunization measles outbreak in Taoyuan County, Taiwan: dynamics of transmission, vaccine effectiveness, and herd immunity

OBJECTIVES

Analysis of national surveillance data and a seroepidemiologic investigation were conducted to elucidate the causes and epidemiologic characteristics of a measles outbreak in Taoyuan, Taiwan, 1994.

METHODS

Measles cases were identified through a national surveillance system. Reported cases and their physician or school nurses were interviewed to trace additional suspect cases and were sampled for serologic diagnosis. Measles-specific IgG and IgM were assayed. A confirmed case was defined as being positive for measles IgM test but not having received measles vaccination within the previous 3 months.

RESULTS

The outbreak began in Taoyuan City in December 1993 and continued to spread in primary schools and kindergartens, but caused only sporadic cases in neighboring towns. Among 42 confirmed cases, 15 (38%) were primary school children and 16 (38%) were kindergarten children. Among 24 confirmed cases with a vaccination record, 7 had one dose of vaccination, 4 had two doses of vaccination, and 13 (54%) were unvaccinated. The overall measles susceptible proportion at a kindergarten before the outbreak was 8.1% (17/209) and the overall measles cumulative incidence among susceptibles was 0.65 (11/17).

CONCLUSIONS

A measles vaccination coverage of 82% with the first dose at 9 months of age and 63% with the second dose (measles, mumps, and rubella) at 15 months was inadequate to block measles virus circulation in Taoyuan City in 1994. The city center, with a growing population, represents a high risk as an epicenter for measles outbreaks. Measles outbreaks may occur in a school population with 92% herd immunity.

Oxidation products of zeylanidine

The oxidation of zeylanidine (1) afforded two new sesquiterpene dilactones, 4 and 5, besides two known compounds, neoliacine (2) and zeylanidinone (3). The structures of the novel oxidized products were elucidated on the basis of spectroscopic techniques, and the structure of compound 5 was further confirmed by X-ray crystallographic analysis. The mechanism for the oxidation of 1 to 4 and 5 has been postulated.

Determination of hydroxyaromatic compounds in water by solid-phase microextraction coupled to high-performance liquid chromatography

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) for the analysis of hydroxyaromatic compounds is described. Three kinds of fibers [50 microns carbowax-templated resin (CW-TPR), 60 microns polydimethylsiloxane-divinylbenzene (PDMS-DVB) and 85 microns polyacrylate (PA) fibers] were evaluated. CW-TPR and PDMS-DVB were selected for further study. The parameters of the desorption procedure (such as desorption mode, the composition of the solvent for desorption and the duration of fiber soaking) were studied and optimized. The effect of the structure and physical properties of analytes, carryover, duration of absorption, temperature of absorption, pH and ionic strength of samples were also investigated. The method was applied to environmental samples (lake water) using a simple calibration curve.

Mixed-valence compound-based biosensor

A cobalt(II)hexacyanoferrate-based biosensor has been prepared simply by codeposition of an enzyme, together with the electrochemical formation of a cobalt (II)hexacyanoferrate compound electrochemically. The compound can be generated at a constant potential of -0.05 V (vs. Ag/AgCl). This compound possesses the catalytic property of reducing hydrogen peroxide to water at the operating potential of 0.0 V vs. Ag/AgCl. The mixed-valence compound-based biosensor possesses an unique interference-independent feature, which is important for biomedical application; this feature is attributed to the low overvoltage characteristic of cobalt (II)hexacyanoferrate. The electrochemical glucose biosensor responds to a series of glucose injections with linearity up to 5 mM (with correlation coefficient R = 0.9999) and the sensitivity of the linear portion is 733 nA/(cm2 x mM). The detection limit is 2 x 10(-6)M (S/N = 3). Both the potential-dependent electron transfer rate constant and the apparent Michaelis-Menten constant were studied in rotating disk experiments. The apparent Michaelis-Menten constant, Km' calculated from the slope of the "Lineweaver-Burke" type reciprocal plot is 28 mM. A fast-response characteristic is observed in the rotating disk experiment and the 95% response time is 14.5 sec. No response was observed from the addition of either 2 x 10(-4)M galactose, acetaminophen, ascorbic acid, uric acid, cysteine, tyrosine, dopamine, or 1,4-dihydroxyquinone in the absence and/or in the presence of 5 x 10(-4)M glucose.

Antibody responses to an immunodominant nonstructural 1 synthetic peptide in patients with dengue fever and dengue hemorrhagic fever

Two flaviviruses, dengue (DEN) virus and Japanese encephalitis (JE) virus, are important because of their global distribution and the frequency of epidemics in tropical and subtropical areas. To study the B-cell epitopes of nonstructural 1 (NS1) glycoprotein and anti-NS1 antibody response in DEN infection, a series of 15-mer synthetic peptides from the predicted B-cell linear epitopes of DEN-2 NS1 protein were prepared. Enzyme-linked immunosorbent assay (ELISA) was performed to analyze antibody responses to these peptides from sera of both DEN and JE patients. One peptide derived from DEN-2 NS1, D2 NS1-P1 (amino acids 1-15), was identified as the immunodominant epitope that reacted with sera from dengue fever (DF) patients but not JE patients. The isotype of D2 NS1-P1-specific antibodies was mainly immunoglobulin M (IgM) in all sera that tested positive. A specificity study demonstrated that sera from all four DEN types reacted with D2 NS1-P1. A dynamics study showed that specific antibodies to this peptide could be detected as early as 2 days after the onset of symptoms. We observed significant anti-D2 NS1-P1 antibody responses in 45% of patients with primary and secondary infections with DF or with dengue hemorrhagic fever. This is the first report demonstrating that significant anti-DEN NS1 antibodies can be induced in the sera of patients with primary DEN infection.

Antiplatelet aggregation constituents from Annona purpurea

Bioactivity-directed fractionation led to the isolation of 19 compounds, including three oxoaporphines, oxopurpureine (5), oxonuciferine (6), and oxoglaucine (7); three aporphines, (+)-predicentrine (8), (-)-glaucine (9), and thalbaicalidine (10); one aporphine sensu stricto, N-formyl-purpureine (11); one proaporphine, glaziovine; one phenanthrene, thalicpureine (12); two 6a,7-dehydroaporphines, dehydrolirinidine (13) and 7-hydroxy-dehydroglaucine (14); four flavonoids, quercetin-3-O-rhamnoside, kaempferol-3-O-rhamnoside, isorhamnetin-3-O-rhamnoside, and tanarixetin-3-O-rhamnoside; one purine, adenine; one lactam amide, squamolone; and two steroids, beta-sitosterol and beta-sitosterol-beta-D-glucoside from the MeOH extract of the leaves of Formosan Annona purpurea. Among them, 11-14 were characterized as new compounds and alkaloids, 5-8, 10, and 12-14 exhibited significant antiplatelet aggregation activity.

Two new 7-dehydroaporphine alkaloids and antiplatelet action aporphines from the leaves of Annona purpurea

Bioactivity-directed fractionation led to the isolation of two new 7-dehydroaporphine alkaloids, 7-hydroxy-dehydrothalicsimidine (1) and 7-formyl-dehydrothalicsimidine (2), along with the five known alkaloids, thalicsimidine (3), norpurpureine (4), N-methyllaurotetanine (5), lirinidine (6) and N-methylasimilobine (7), from the leaves of Annona purpurea. Structural elucidation of these compounds was established by mass and spectroscopic analyses. Among them, 1, 3, 4, 6 and 7 exhibited significant inhibition of collagen, arachidonic acid and platelet activating factor-induced platelet aggregation; 1 also showed inhibition against thrombin-induced platelet aggregation.

Rhinacanthin-Q, a naphthoquinone from Rhinacanthus nasutus and its biological activity

The continuing investigation of the root of Rhinacanthus nasutus afforded a 1,4-naphthoquinone ester, rhinacanthin-Q, accompanied by twenty-four known compounds. The structure was elucidated on the basis of spectroscopic analyses. The cytotoxicity and antiplatelet effect of this compound was also discussed.

Two p-quinonoid aporphine alkaloids from fissistigma balansae

Investigation of the ethanolic extract from the twigs of Fissistigma balansae resulted in the isolation of two new p-quinonoid aporphine alkaloids, named fissilandione (1) and norfissilandione (2). The structures of 1 and 2 were elucidated on the basis of spectral data and confirmed by chemical conversions.

The endogenous calcium buffer and the time course of transducer adaptation in auditory hair cells

Mechanoelectrical transducer currents in turtle auditory hair cells adapt to maintained stimuli via a Ca2+-dependent mechanism that is sensitive to the level of internal calcium buffer. We have used the properties of transducer adaptation to compare the effects of exogenous calcium buffers in the patch electrode solution with those of the endogenous buffer assayed with perforated-patch recording. The endogenous buffer of the hair bundle was equivalent to 0.1-0.4 mM BAPTA and, in a majority of cells, supported adaptation in an external Ca2+ concentration of 70 microM similar to that in turtle endolymph. The endogenous buffer had a higher effective concentration, and the adaptation time constant was faster in cells at the high-frequency end than at the low-frequency end of the cochlea. Experiments using buffers with different Ca2+-binding rates or dissociation constants indicated that the speed of adaptation and the resting open probability of the transducer channels could be differentially regulated and imply that the endogenous buffer must be a fast, high-affinity buffer. In some hair cells, the transducer current did not decay exponentially during a sustained stimulus but displayed damped oscillations at a frequency (58-230 Hz) that depended on external Ca2+ concentration. The gradient in adaptation time constant and the tuned transducer current at physiological levels of calcium buffer and external Ca2+ suggest that transducer adaptation may contribute to hair cell frequency selectivity. The results are discussed in terms of feedback regulation of transducer channels mediated by Ca2+ binding at two intracellular sites.

Minimally invasive cardiac surgery for intracardiac congenital lesions

OBJECTIVE

Minimally invasive cardiac surgery has recently been applied to the correction of intracardiac lesions. This report reviews our experience of minimally invasive cardiac surgery in 119 patients with intracardiac congenital lesions.

METHODS

From October 1995 to April 1997, 119 patients (48 male and 71 female, aged 0.9-65 years old, 18.5+/-17.8) received elective minimally invasive cardiac surgery at Chang Gung Memorial Hospital, Taipei, Taiwan for repair of atrial septal defect (96 patients) or ventricular septal defect (23 patients). The operations were performed through right submammary incision (ASD) or left parasternal minithoracotomy (VSD), under femoro-femoral or femoro-atrial cardiopulmonary bypass with fibrillatory arrest.

RESULTS

All of the defects were repaired successfully. The bypass time was 25-125 min (46+/-18). The operation time was 1.5-5.2 h (2.8+/-0.8). The postoperative course was uneventful in all patients. Follow-up (1.0-18.2 months, mean 7.3) was complete, with no late deaths or residual shunt. All patients were found to be in NYHA functional class I or II.

CONCLUSION

Our experience demonstrate that minimally invasive cardiac surgery is a technically feasible, safe, and effective procedure in surgical correction of selective simple intracardiac congenital lesions, yielding good short-term results.

Management of descending necrotizing mediastinitis

BACKGROUND

Descending necrotizing mediastinitis (DNM) is uncommon, and may be lethal if not treated adequately and promptly. Delayed diagnosis of the disease is sometimes encountered in clinical practice.

METHODS

Eight consecutive patients with acute DNM were identified between 1991 and 1995, including five men and three women. The mean age was 45.8 years (range, 22-71 years). The infectious sources consisted of six esophageal perforations, one cervical cutting injury and one tonsillitis. The clinical presentations were evaluated. Diagnostic procedures including chest radiograph, sonogram and computerized tomography scans of the chest and neck were examined. Diagnosis and treatment, including culture results from drained fluids and debrided tissues, and antibiotic and supportive therapies were reviewed.

RESULTS

Six patients who underwent aggressive surgical treatment recovered well. Two patients who received supportive treatment died of sepsis alone. The cultured bacteria included: Klebsiella oxytoca, Staphylococcus aureus, Trichosporum and other mixed oral cavity flora.

CONCLUSIONS

Early diagnosis and adequate antibiotic and support therapies are essential to achieve good patient outcomes in acute descending mediastinitis. Adequate drainage and debridement, appropriate antibiotic therapy, and sufficient nutritional and respiratory support are the main treatment elements.

Chemical constituents from Cassytha filiformis II

Using a bioassay-directed fractionation method, three new compounds, including an aporphine alkaloid, cassyformine (4); an oxoaporphine alkaloid, filiformine (8), and a lignan, (+)-diasyringaresinol (10), along with 14 known compounds, were further isolated and characterized from the MeOH extract of the fresh herbs of Cassytha filiformis. Among the isolates of this plant, cathafiline (1), cathaformine (2), actinodaphnine (3), N-methylactinodaphnine (5), predicentrine (6), and ocoteine (7) exhibited significant antiplatelet aggregation activity.

The C. elegans cell corpse engulfment gene ced-7 encodes a protein similar to ABC transporters

The C. elegans gene ced-7 functions in the engulfment of cell corpses during programmed cell death. We report that the CED-7 protein has sequence similarity to ABC transporters, is broadly expressed during embryogenesis, and is localized to the plasma membrane. Mosaic analysis revealed that ced-7 functions in both dying cells and engulfing cells during the engulfment process. We propose that CED-7 functions to translocate molecules that mediate homotypic adhesion between the cell surfaces of the dying and engulfing cells. Like CED-7, the mammalian ABC transporter ABC1 has been implicated in the engulfment of cell corpses, suggesting that CED-7 and ABC1 may be functionally similar and that the molecular mechanism underlying cell corpse engulfment during programmed cell death may be conserved from nematodes to mammals.

Antigenic characterization of nine wild-type Taiwanese isolates of Japanese encephalitis virus as compared with two vaccine strains

The antigenic properties of nine wild-type Japanese encephalitis viruses isolated in Taiwan during 1990 1994 were investigated by comparison with two inactivated vaccine strains (Beijing-1, Nakayama-NIH). All of the nine Taiwanese isolates were found to induce higher cytopathology in Vero cells but showed similar mouse virulence as the two vaccine strains. Antigenic characterization using six E protein-specific monoclonal antibodies shows two of the nine wild-type isolates (i.e. CH1949 and CH2195) presented different antigenic properties of hemagglutination inhibition and plaque reduction neutralization. The E-protein gene nucleotide sequences of CH1949 and CH2195 were determined and compared with other published sequences of the two vaccine strains and other 19 Asian/Taiwanese isolates. Phylogenetic tree analysis indicates these two wild-type Taiwanese isolates are more distant from the two vaccine strains.

C. elegans phagocytosis and cell-migration protein CED-5 is similar to human DOCK180

During programmed cell death, cell corpses are rapidly engulfed. This engulfment process involves the recognition and subsequent phagocytosis of cell corpses by engulfing cells. How cell corpses are engulfed is largely unknown. Here we report that ced-5, a gene that is required for cell-corpse engulfment in the nematode Caenorhabditis elegans, encodes a protein that is similar to the human protein DOCK180 and the Drosophila melanogaster protein Myoblast City (MBC), both of which have been implicated in the extension of cell surfaces. ced-5 mutants are defective not only in the engulfment of cell corpses but also in the migrations of two specific gonadal cells, the distal tip cells. The expression of human DOCK180 in C. elegans rescued the cell-migration defect of a ced-5 mutant. We present evidence that ced-5 functions in engulfing cells during the engulfment of cell corpses. We suggest that ced-5 acts in the extension of the surface of an engulfing cell around a dying cell during programmed cell death. We name this new family of proteins that function in the extension of cell surfaces the CDM (for CED-5, DOCK180 and MBC) family.

Bioactive kaurane diterpenoids from Annona glabra

Phytochemical analysis of the fruits of Annona glabra yielded two new kaurane diterpenoids, annoglabasin A (methyl-16 beta-acetoxy-19-al-ent-kauran-17-oate)(1) and annoglabasin B (16 alpha-hydro-19-acetoxy-ent-kauran-17-oic acid)(2), along with 11 known kaurane derivatives (3-13). The structures of the new compounds were established by spectral and chemical evidence. Among these, methyl-16 alpha-hydro-19-al-ent-kauran-17-oate (11) exhibited mild activity against HIV replication in H9 lymphocyte cells, and 16 alpha-17-dihydroxy-ent-kauran-19-oic acid (4) showed significant inhibition of HIV-reverse transcriptase.

Two novel compounds from Paeonia suffructicosa

A new hexacyclic triterpenoid, mudanpinoic acid A (1), and a new gallic acid glycoside, mudanoside B (2), along with nine known compounds--benzoic acid, resacetophenone, paeoniflorigenone, beta-sitosterol, betulinic acid, oleanoic acid, quercetin, beta-sitosterol-beta-D-glucoside, and trans-caffeic acid stearyl ester-were isolated from the dried root cortex of Paeonia suffruticosa. The structures of the novel compounds were elucidated on the basis of spectral methods, and that of compound 1 was confirmed by X-ray crystallographic analysis.

Acetogenins from seeds of Annona reticulata

Chromatography of an ethyl acetate extract of seeds of Annona reticulata led to the isolation of a new cytotoxic gamma-lactone acetogenin, cis-/trans-isomurisolenin, along with six known cytotoxic acetogenins, annoreticuin, annoreticuin-9-one, bullatacin, squamocin, cis-/trans-bullatacinone and cis-/trans-murisolinone. Structures of these compounds were established by means of mass and related spectral experiments. Some of the compounds isolated, showed potent cytotoxicities against Hep. 2,2,15, Hep. G2, KB and CCM2, four cancer cell-lines.

Lymph node metastasis in squamous cell carcinoma of the intrathoracic esophagus

BACKGROUND

In esophageal carcinoma lymph node metastasis is one of the most important factors of prognosis. This prospective study evaluated the incidence and extent of lymph node metastasis, and assessed the relationship between the depth of tumor invasion and lymph node metastasis in esophageal carcinoma.

METHODS

Between 1985 and 1996, tissue samples from 112 patients undergoing radical esophagectomy and gastric substitution for squamous cell carcinoma of the intrathoracic esophagus were collected. Patients with distant organ metastasis were excluded. All specimens were evaluated and sent for histopathologic examination.

RESULTS

In 108 men and four women with a mean age of 63.1 years, the average number of dissected lymph nodes in one surgical procedure, was 30 per person. The most commonly involved nodes were the periesophageal (42.9%) and the perigastric (42.9%) nodes, followed by the recurrent laryngeal nerve (23.8%) and thoracic paratracheal (22.2%) nodes. For tumors in the upper third of the esophagus, the most frequently involved nodal groups were the periesophageal (28.6%) and the paratracheal (28.6%) nodes, followed by the recurrent laryngeal nerve (21.4%) the deep cervical (21.4%), and the perigastric (21.4%) nodes. For tumors in the middle third of the esophagus, the periesophageal nodes (27.3%) were most commonly involved, followed by the perigastric (18.2%) and the subcarina (10.6%) nodes. For tumors in the lower third of the esophagus, the perigastric lymph nodes (37.5%) were the most common nodal metastatic site, followed by the celiac (18.8%) and the recurrent laryngeal nerve (18.2%) nodes. Depth of tumor invasion was also found to correlate significantly with lymph node metastasis (p = 0.0015).

CONCLUSIONS

Wide lymph node metastasis between the neck and the upper abdomen occurs frequently in squamous cell carcinoma of the esophagus. For potentially curable esophageal carcinomas, en-bloc esophagectomy with complete locoregional lymph node dissection may provide favorable local control of the lesion and more accurate tumor staging.

Minimally invasive approach for coronary artery bypass surgery

Forty-two patients, 33 male and 9 female, aged 35.7 to 81.6 years old (mean 62.7), were operated on for left main and/or triple vessel coronary artery disease by using minimally invasive cardiac surgical techniques. A myocardial infarction had occurred in 26 patients (61.9%). The left ventricular ejection fraction ranged from 17 to 83% (52+/-22). The surgeries were performed through left parasternal minithoracotomy (8 to 12 cm in length) under femoro-femoral or aorto-atrial cardiopulmonary bypass. The myocardium was protected by blood cardioplegic solution with the aorta crossclamped. Under direct vision, average 3.8 distal anastomoses were performed in each patient, with the saphenous vein grafts and the left internal thoracic arterial graft. The aortic crossclamp time was 62 to 137 min (80+/-15). The duration of cardiopulmonary bypass was 88 to 168 min (115+/-24). The postoperative course was uneventful in all patients. Follow-up (1.0 to 5.6 months, mean 2.9) was complete in all patients and there were no late deaths or angina. Coronary angiography of ten patients showed patent grafts. Our experience demonstrates that minimally invasive cardiac surgery during cardioplegic arrest is technically feasible and can be performed in coronary artery disease safely and effectively for complete revascularization.

[Detection of neutralizing antibodies to Japanese encephalitis virus by enzyme-linked immunosorbent assay (ELISA)]

Competitive ELISA was used for the detection of neutralizing antibody to JE. Based on the principle that human serum JE antibody competed with JE monoclonal antibody (MAb) for JE antigen, it was found that 3 JE MAbs (E3-3, NPF-5 and NNN-5) were suitable for competitive ELISA for the detection of JE neutralizing antibody. The sensitivity of cometitive ELISA for 29 JE confirmed serum specimens with titer of plaque reduction neutralization test (PRNT) was checked to be 82.1% (23/28). The specificity of E3-3 MAb to JE used in competitive ELISA was 100%. Correlation coefficient of JE confirmed cases of 57 hemagglutination inhibition (HI) titers in 1995 and 37 PRNT titers in 1994 compared with competitive ELISA were 0.744 and 0.732, respectively. Compared the competitive ELISA titers of 154 sera of healthy people with PRNT titers, the results showed that 70% of the sera could be detected by competitive ELISA which saved a lot of time and manpower.

Primary pulmonary malignant hemangiopericytoma associated with coagulopathy

A 34-year-old woman with a massive pulmonary malignant hemangiopericytoma and coagulopathy as a paraneoplastic syndrome is reported. Although coagulopathy may appear as a paraneoplastic syndrome and cause treatment to be more complicated and difficult, it can also be a useful marker to monitor the results of operation and tumor recurrence. This unusual case shows that primary pulmonary malignant hemangiopericytoma deserves aggressive surgical intervention with complete resection even under the circumstances of coagulation abnormality.

[Seroepidemiology of Japanese encephalitis viral infection among 3-6 years old children from mountainous and plains townships located in the northern, central, southern and eastern Taiwan]

In order to evaluate the Japanese encephalitis virus (JEV) vaccination program in rural Taiwan, we conducted a seroepidemiological survey of JEV among rural children 3 to 6 years of age in Taiwan. The children were selected through a systemic sampling following stratification by age of children in 4 selected aboriginal villages and 4 adjacent nonaboriginal villages. The overall vaccine coverage rate for the primary (2 doses) dose was 81.2% (1853/2281) with higher rates (87.7%-87.9%) found among the more recent birth cohort of 3 to 4 years of age. The neutralizing antibody (NT) against JEV was measured with plaque reduction neutralization test (PRNT) using Nakayama strain as the virus. With a positive NT antibody defined as > or = 1:10 dilution of serum yielding more than 50% plaque reduction, the overall JEV NT antibody positive rate among children receiving 3 doses of vaccine was 67%. However, the age-specific positive rates varied significantly with varying ages; the lowest of 47% being among children 4 years of age which was lower than the rates of 68%, 76% and 87% among children of 3, 5 and 6 years of age, respectively. This trend of rising seropositive rates of JEV antibody with increasing age among 4 and 6 years of age was also noted among children who had received no vaccine, suggesting the importance of natural infection among rural Taiwanese children. Despite the high frequency of natural infection, the seropositive rates of JEV antibody still correlated well with the dose of vaccine received, i.e., 67% (1122/1664), 66% (65/97), 33% (4/12) and 40% (19/47) for children receiving 3, 2, 1, and 0 dose of JE vaccines, respectively (P < 0.0001 Chi-square for trend test). When stratified analysis by dose and by type of vaccines was conducted, a significantly higher seropositive rate of JEV NT antibody was noted among children receiving JE vaccine of Beijing type (87%) than children receiving Nakayama type (39%) (p < 0.0001, Chi-square test). Our data indicated that the JEV vaccination, in conjunction with JEV natural infection, has maintained high JEV NT antibody level among rural children of Taiwan.

Multi-undulant T-U-wave, sinus bradycardia and long QT syndrome: a possible phenotype of mutant genes controlling the inward potassium rectifiers

Inward rectifying potassium currents (Ikr and Iks) during phase 3 repolarization of the myocyte from the beginning to the end of repolarization of the myocardial syncytium will inscribe a T-U-wave on the surface electrocardiogram (ECG). Type two congenital long QT syndrome (LQT2) is a phenotype of human ether-a-go-go-related gene (HERG) mutation on the chromosome 7q 35-36. Type one congenital long QT syndrome (LQT1) is a phenotype of KvLQT1 mutation on the chromosome 11p15.5. Both LQT1 and LQT2 relate with inward rectifying potassium currents and is repolarization related, therefore, it is speculate that patients of LQT1 and LQT2 may have an abnormal T-U-wave on their surface ECG. To two probands of congenital LQT, 8 patients of structural heart disease treated by open heart surgery, 13 patients of structural heart disease without open-heart surgery, and 10 patients of normal controls, 24 hour-Holter monitoring was performed from July to December 1996. Their corrected QT interval (QTc) as well as the RR interval of every heart beat was calculated by a computer. The results showed that all 33 patients exhibited beat-by-beat fluctuation of their QTc and RR daily. The RR intervals of these two probands of congenital LQT were somewhile more than 1200 ms during circadian waking time, while 31 cases without LQT showed their RR prolongation only during the circadian sleeping time. A multi-undulant T-U-wave, or a beat-to-beat changing of vectors or amplitudes of their T-U-wave observed in these two probands of congenital LQT, were not observable in those 31 patients without congenital LQT. Therefore, we concluded that multi-undulant T-U-wave, sinus bradycardia and a longer QTc was a phenotype of the mutated genes which control the inward rectifying potassium currents during phase 3 repolarization.

Bioactive alkaloids from Illigera luzonensis

Using antiplatelet aggregation as a guide to fractionation, seven aporphines, actinodaphnine (1), N-methylactinodaphnine (2), launobine (3), dicentrine (4), O-methylbulbocapnine (5), hernovine (7), and bulbocapnine (9), and two oxoaporphines, dicentrinone (6) and liriodenine (8), were isolated from the stems of Illigera luzonensis. Among them, compounds 2, 4, 5, 8, and 9 were isolated for the first time from this species. Moreover, compounds 1-5, and 8 showed significant antiplatelet aggregation and compounds 1 and 6 exhibited significant vasorelaxant activities, respectively.

Pharmacological evaluation of ocoteine, isolated from Cassytha filiformis, as an alpha 1-adrenoceptor antagonist in rat thoracic aorta

Ocoteine, isolated from Cassytha filiformis, was found to be an alpha 1-adrenoceptor blocking agent in rat thoracic aorta as revealed by its competitive antagonism of phenylephrine-induced vasoconstriction (pA2 = 7.67 +/- 0.09). Removal of endothelium from the aorta did not affect its antagonistic potency (pA2 = 7.97 +/- 0.07). [3H]-Inositol monophosphate formation caused by noradrenaline (3 microM) was suppressed by ocoteine (10 microM) and prazosin (3 microM). Ocoteine did not affect the contraction induced by U-46619, prostaglandin F2 alpha or angiotensin II, but inhibited slightly those by high K+ and endothelin I. Neither the cyclic AMP nor cyclic GMP content of rat thoracic aorta was changed by ocoteine (10 microM). Comparing the EC50 values, the potency of ocoteine against 5-hydroxytryptamine (5-HT) was about 60 times less than that against phenylephrine. Ocoteine (10 microM) also slightly antagonized the clonidine-induced inhibition of the twitch response evoked by field stimulation in rat vas deferens. In guinea pig trachea, the contraction caused by carbachol, histamine, neurokinin A or leukotriene C4 and beta 2-adrenoceptor-mediated relaxing responses induced by isoprenaline were not affected by ocoteine (10 microM). The voltage clamp study in rat ventricular single myocytes revealed that ocoteine (3, 10 microM) inhibited steady state outward currents, but not transient outward currents or slow inward Ca2+ currents. It is concluded that ocoteine is a selective alpha 1-adrenoceptor antagonist in isolated rat thoracic aorta. At high concentrations, it also blocks 5-HT receptors and Na+ and steady state outward currents in rat ventricular myocytes.

Concordance of positive and negative symptoms in coaffected sib-pairs with schizophrenia

Positive and negative symptom (NGS) dimensions were examined for their concordance in 46 coaffected schizophrenic sib-pairs. Results showed that the symptom dimensions of negative symptoms (NGS), delusion-hallucination (DHS), and thought disorganization (TDS) could be formulated. Discrete genetic endowment of these three symptom dimensions was not found as shown by the low concordance in sib pair analysis (kappa = 0.20-0.30). Thirty-seven pairs (80.4%) and 21 pairs (45.7%) had liability, defined by the presence of NGS in any one member of the coaffected sib-pairs, of NGS of "any degree", and of "severe degree" in 46 sib-pairs, respectively. Both groups had high prevalence (59.1-81.0%) of positive symptoms. Another 9 (19.6%) and 25 (54.3%) pairs had no liability of NGS of "any degree" or of "severe degree" out of 46 sib-pairs, respectively. These two groups had high concordance (kappa = 0.45-1.00) of TDS or DHS between coaffected sib-pairs. Based on the results, it is hypothesized that schizophrenia, as defined by DSM-III-R, may consist of two subtypes: one has liability of NGS and a high prevalence of positive symptoms, while the other has only positive symptoms.

Disparate changes in plasma and tissue pentosidine levels after kidney and kidney-pancreas transplantation

The advanced glycation end-product, pentosidine, was measured in plasma proteins and skin collagen before and after kidney and kidney-pancreas transplantation in order to determine the relationship between plasma and tissue levels and to characterize the pattern of change in pentosidine levels after correction of hyperglycemia and/or renal failure. The content of pentosidine in skin collagen was higher than that in plasma proteins both before and after transplantation. However, there was no correlation between plasma and skin pentosidine levels. Prior to transplantation, the content of pentosidine in skin collagen was related to the duration of dialytic therapy, presence of diabetes mellitus, age, and female gender. Following transplantation, plasma pentosidine levels were inversely correlated with glomerular filtration rate (r = 0.64; p < 0.01). While plasma pentosidine levels consistently decreased after transplantation, levels in skin collagen increased in 10 of 13 patients, including 5 of 6 recipients of kidney-pancreas transplants. Our results indicate that tissue levels of pentosidine persist for long periods of time after kidney or kidney-pancreas transplantation, despite consistent decreases in levels measured in plasma proteins. The observed increase in tissue pentosidine levels in a majority of patients suggests that formation of advanced glycation end-products may continue after otherwise successful kidney or kidney-pancreas transplantation.

Complete nucleotide sequence of the genome of Japanese encephalitis virus ling strain: the presence of a 25-nucleotide deletion in the 3'-nontranslated region

The complete sequence of the genome of the Japanese encephalitis virus (JEV) Ling strain isolated from the brain of a patient in Taiwan in 1965 was cloned by using the reverse transcription-polymerase chain reaction method. Seven overlapping cDNA clones that span the entire virus genome were isolated and sequenced to determine the complete nucleotide sequence, which is 10,951 nucleotides in length. As reported for three other JEV strains (Beijing-1, SA-14, and JaOArS982), the Ling strain contains 95 nucleotides in the 5' nontranslated region (NTR), followed by a single open reading frame of 10,296 nucleotides. However, the length of the 3' NTR of JEV Ling is 560 nucleotides, 25 nucleotides shorter than that of other JEV strains sequenced to date. Comparison of nucleotide and amino acid sequences among these four JEV strains showed that nucleotide (amino acid) sequence divergence in the translated region varied from 1.25% to 3.27% (0.49-1.63%). The nucleotide (amino acid) divergences between the Ling and Beijing-1 strains were 1.25% (0.87%) and between the SA-14 and JaOArS982 strains were 1.42% (0.49%). These values are lower than those found between the Ling and SA-14 [2.44% (1.02%)] or the Ling and JaOArS982 strains [2.84% (0.93%)], as well as those between Beijing-1 and SA-14 [3.14% (1.60%)] or Beijing-1 and JaOArS982 [3.27% (1.63%)] strains. Sequence comparisons of subregions of the genomes i.e., structural genes, nonstructural genes, or individual genes, showed divergence similar to that obtained by comparing the entire sequence. It is likely that the JEV sequence divergence between two human isolates or between two mosquito isolates is lower than that between a human isolate and a mosquito isolate.

A theoretical study of calcium microdomains in turtle hair cells

Confocal imaging has revealed microdomains of intracellular free Ca2+ in turtle hair cells evoked by depolarizing pulses and has delineated factors affecting the growth and dissipation of such domains. However, imaging experiments have limited spatial and temporal resolution. To extend the range of the results we have developed a three-dimensional model of Ca2+ diffusion in a cylindrical hair cell, allowing part of the Ca2+ influx to occur over a small circular region (radius 0.125-1.0 micron) representing a high-density array of voltage-dependent channels. The model incorporated experimental information about the number of channels, the fixed and mobile Ca2+ buffers, and the Ca2+ extrusion mechanism. A feature of the calculations was the use of a variable grid size depending on the proximity to the Ca2+ channel cluster. The results agreed qualitatively with experimental data on the localization of the Ca2+ transients, although the experimental responses were smaller and slower, which is most likely due to temporal and spatial averaging in the imaging. The model made predictions about 1) the optimal Ca2+ channel number and density within a cluster, 2) the conditions to ensure independence of neighboring clusters, and 3) the influence of the Ca2+ buffers on the kinetics and localization of the microdomains. We suggest that an increase in the mobile Ca2+ buffer concentration in high-frequency hair cells (which possess a larger number of release sites) would allow lower amplitude and faster Ca2+ responses and promote functional independence of the sites.

Electrophysiological mechanisms for antiarrhythmic efficacy and positive inotropy of liriodenine, a natural aporphine alkaloid from Fissistigma glaucescens

1. The antiarrhythmic potential and electromechanical effects of liriodenine, an aporphine alkaloid isolated from the plant, Fissistigma glaucescens, were examined. 2. In the Langendorff perfused (with constant pressure) rat heart, at a concentration of 0.3 to 3 microM, liriodenine was able to convert a polymorphic ventricular tachyrhythmia induced by the ischaemia-reperfusion (EC50 = 0.3 microM). 3. In isolated atrial and ventricular muscle, liriodenine increased the contractile force and slowed the spontaneous beating of the right atrium. 4. The liriodenine-induced positive inotropy was markedly attenuated by a transient outward K+ channel blocker, 4-aminopyridine (4-AP) but was not significantly affected by prazosin, propranolol, verapamil or carbachol. 5. In rat isolated ventricular myocytes, liriodenine prolonged action potential duration and decreased the maximal upstroke velocity of phase 0 depolarization (Vmax) and resting membrane potential in a concentration-dependent manner. The action potential amplitude was not significantly changed. 6. Whole-cell voltage clamp study revealed that liriodenine blocked the Na+ channel (INa) concentration-dependently (IC50 = 0.7 microM) and caused a leftward shift of its steady-state inactivation curve. However, its recovery rate from the inactivated state was not affected. The L-type Ca2+ currents (Ica) were also decreased, but to a lesser degree (IC50 = 2.5 microM, maximal inhibition = 35%). 7. Liriodenine inhibited the 4-AP-sensitive transient outward current (Ito) (IC50 = 2.8 microM) and moderately accelerated its rate of decay. The block of Ito was not associated with changes in the voltage-dependence of the steady-state inactivation curve or in the process of recovery from inactivation of the current. Liriodenine also reduced the amplitude of a slowly inactivating, steady-state outward current (Iss) (IC50 = 1.9 microM). These effects were consistent with its prolonging effect on action potential duration. The inwardly rectifying background K+ current (IK1), was also decreased but to a less degree. 8. Compared to quinidine, liriodenine exerted a stronger degree of block on INa, comparable degree of block on IK1, and lesser extent of block on ICa and Ito. 9. It is concluded that, through inhibition of Na+ and the Ito channel, liriodenine can suppress ventricular arrhythmias induced by myocardial ischaemia reperfusion. The positive inotropic effect can be explained by inhibition of the Ito channel and the subsequent prolongation of action potential duration. These results provide a satisfactory therapeutic potential for the treatment of cardiac arrhythmias.

Detection of IgM antibody to Japanese encephalitis virus infection by enzyme-linked immunosorbent assay (ELISA)

BACKGROUND

Japanese encephalitis (JE) is an important infectious disease in Taiwan, with reported cases observed all the year around. Laboratory tests for JE consist mainly of hemagglutination inhibition (HI) test and neutralization test (NT). Commercialized enzyme-linked immunosorbent assay (ELISA) kits for detection of JE-IgM are still not available. Therefore an attempt has been made to develop a sensitive and rapid ELISA for detection of the IgM antibody to JE to serve as an indication of recent Japanese encephalitis virus infection.

METHODS

Both positive and negative JE serum specimens, confirmed by HI test, were checked for IgM antibody to JE by ELISA. The optimum concentration of biotin-IgG and avidin horse-radish peroxidase conjugate used in MAC-ELISA were 1/2000 and 1/ 15000, respectively.

RESULTS

From 1987 to 1989, 118 paired serum specimens of HI-confirmed JE patients were tested for JE-IgM by ELISA. The positive rate of JE-IgM was 65.7% (25/38), 73.9% (17/23), 93.5% (29/31) and 88.8% (8/9) for the consecutive first to fourth weeks after onset of the disease. The JE-IgM antibody of 17 serum specimens collected from the 5th to the 10th week after onset of the disease were 100% detected. In addition, among the 13 HI-confirmed JE cases occurring in 1994, 84.6% of the acute phase serum specimens demonstrated the JE-IgM antibody.

CONCLUSIONS

About 65.7% of the JE-IgM of the acute serum specimens collected within one week after onset of the disease were detected. The JE-IgM positive rate elevated as the days from disease onset increased. Therefore the appearance of JE-IgM could be used as an indication of recent JEV infection to serve as a rapid laboratory diagnostic tool.

A developmental model for generating frequency maps in the reptilian and avian cochleas

Hair cells in the turtle cochlea are frequency-tuned by a mechanism involving the combined activation of voltage-sensitive Ca2+ channels and Ca(2+)-activated K+ (KCa) channels. The main determinants of a hair cell's characteristic frequency (Fo) are the KCa channels' density and kinetics, both of which change systematically with location in the cochlea in conjunction with the observed frequency map. We have developed a model based on the differential expression of two KCa channel subunits, which when accompanied by concurrent changes in other properties (e.g., density of Ca2+ channels and inwardly rectifying K+ channels), will generate sharp tuning at frequencies from 40 to 600 Hz. The kinetic properties of the two subunits were derived from previous single-channel analysis, and it was assumed that the subunits (A and B) combine to form five species of tetrameric channel (A4, A3B, A2B2, AB3, and B4) with intermediate kinetics and overlapping distribution. Expression of KCa and other channels was assumed to be regulated by diffusional gradients in either one or two chemicals. The results are consistent with both current- and voltage-clamp data on turtle hair cells, and they show that five channel species are sufficient to produce smooth changes in both Fo and kinetics of the macroscopic KCa current. Other schemes for varying KCa channel kinetics are examined, including one that allows extension of the model to the chick cochlea to produce hair cells with Fo's from 130 to 4000 Hz. A necessary assumption in all models is a gradient in the values of the parameters identified with the cell's cytoplasmic Ca2+ buffer.

Identification of ent-16 beta, 17-dihydroxykauran-19-oic acid as an anti-HIV principle and isolation of the new diterpenoids annosquamosins A and B from Annona squamosa

Phytochemical analysis of the fruits of Annona squamosa yielded 12 known kaurane derivatives (1-11, 13) and two new kaurane diterpenoids, which have been named annosquamosin A (16 beta-hydroxy-17-acetoxy-ent-kauran-19-al) (12) and annosquamosin B (19-nor-ent-kaurane-4 alpha,16 beta,-17-triol) (14). The structures of the new compounds were established by spectral analyses and chemical evidence. Among these 14 compounds, 16 beta, 17-dihydroxy-ent-kauran-19-oic acid (2) showed significant activity against HIV replication in H9 lymphocyte cells with an EC50 value of 0.8 microgram/mL (therapeutic index > 5).

The advanced glycation endproduct pentosidine and monocyte activation in uremia

RATIONALE

Advanced glycation endproducts (AGEs) contribute to the pathogenesis of vascular complications in diabetes, aging and end-stage renal disease (ESRD). Immune abnormalities in patients with chronic renal failure and those treated by dialysis contribute to high rates of morbidity and mortality. We therefore sought a relationship between a circulating marker of immune dysfunction and plasma levels of the AGE pentosidine.

METHOD

We studied non-diabetic patients with mild to advanced renal failure (n = 60), and with ESRD treated by hemodialysis (HD) (n = 44) and peritoneal dialysis (PD) (n = 19). The plasma protein content of the well characterized AGE, pentosidine was measured using HPLC. In the same samples the monocyte activation product neopterin was measured by RIA.

RESULTS

Plasma levels of pentosidine and neopterin increased in parallel with the progression of renal failure. Pentosidine and neopterin were highly correlated in all patients even after adjustment for Ccr. This correlation was also present in patients with ESRD.

CONCLUSION

These data suggest that the AGE pentosidine is associated with monocyte activation in renal failure, an interaction which may contribute to accelerated rates of complication and death by as yet unknown mechanisms.

Antiplatelet of vasorelaxing actions of some benzylisoquinoline and phenanthrene alkaloids

Members of a series of benzylisoquinoline and phenanthrene alkaloids were tested for their antiplatelet and vasorelaxing actions. Atherosperminine HClO4 (15) and atherosperminium I (16) showed strong inhibition of adenosine 5'-diphosphate-induced platelet aggregation. dl-N-Methylcoclaurine (1), dl-coclaurine (6), 15, 16, xylopine hydroxylamine (18), and atherosperminine N-oxide (19) showed strong inhibition of arachidonic acid-induced platelet aggregation. Compounds 1, 15, 16, dicentrine methine (17), 18, and 19 showed strong inhibition of collagen-induced platelet aggregation. d-(-)-Magnocurarine I (8), 15, and 16 showed strong inhibition of platelet-activating factor-induced platelet aggregation. Compounds 15, 17, and 19 showed vasorelaxing action in rat thoracic aorta.

Antiplatelet and vasorelaxing actions of some aporphinoids

A series of aporphines and oxoaporphines was tested for antiplatelet and vasorelaxing actions. (+)-N-Methylactinodaphnine, (-)-norannuradhapurine x HBr, xylopine, actinodaphnine, and N-methylnandigerine showed strong inhibition of adenosine 5'-diphosphate (ADP)-induced platelet aggregation. Boldine, (+)-N-methylactinodaphnine, (-)-norannuradhapurine x HBr, xylopine, N-acetyllaurolitsine, N-methyllaurotetanine, actinodaphnine, N-methylnandigerine, O-methylbulbocapnine, and liriodenine showed strong inhibition of arachidonic acid (AA)-induced platelet aggregation. (+)-N-Methylactinodaphnine, fissoldine x HCIO4, (-)-norannuradhapurine x HBr, xlylopine, N-methyllaurotetanine, actinodaphnine, N-methylnandigerine, O-methylbulbocapnine, and liriodenine showed strong inhibiton of collagen-induced platelet aggregation. (-)-Norannuradhapurine x HBr, xylopine, N-methyllaurotetanine, and actinodaphnine showed strong inhibition of platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine)-induced platelet aggregation. (+)-N-Methylactinodaphnine, laurotetanine, N-methylactinodaphnine N-oxide, oxoglaucine, boldine, and actinodaphnine showed vasorelaxing action in rat thoracic aorta. The results are discussed on the basis of structure-activity relationships.

Identification of immunodominant, group-specific and subcomplex-specific, continuous epitopes in the core regions of Japanese encephalitis virus using synthetic peptides

Two flaviviruses, Japanese encephalitis (JE) virus and Dengue (DEN) virus which have high pathogenicity for humans, continue to pose a serious public health problem in tropical and subtropical countries of the world. In order to identify the immunodominant B-cell epitopes for diagnostic application, we have prepared a series of 15-mer synthetic peptides from JE virus core protein based on computer analysis. Four linear, immunodominant epitopes corresponding to amino acids 91-105 (P78), 1-15 (P73), 8-22 (P74), and 34-48 (P75) of JE virus core proteins were identified by employing an enzyme-linked immunosorbent assay (ELISA), using high-titered immune sera from JE-vaccinated children. P78 was found to be the most immunodominant. The sero-specificity of these peptides was tested by binding to seroconverted samples from JE and DEN-1 patients. P78 and P74 belonged to group-specific epitopes which reacted with both JE and DEN-1 patient sera. P73 and P75 belonged to subcomplex-specific epitopes which reacted only with JE but not with DEN-1 patient sera. The study suggests that these peptides corresponding to the immunodominant epitopes of JE virus core protein might have the potential to be used as peptide-based diagnostic reagents for the detection and differentiation of JE and DEN antibody responses.

Delayed clearance of transmitter and the role of glutamate transporters at synapses with multiple release sites

The roles of glutamate diffusion, uptake, and channel kinetics in shaping the AMPA receptor EPSC were examined at a calyceal synapse. The EPSC decay was described by three exponential components: two matching desensitizing channel kinetics, and a third component at least 10 times slower. The slowest component had identical voltage dependence to the steady-state AMPA current and was selectively increased and prolonged by blockade of glutamate uptake, indicating that the slow EPSC represented rebinding of glutamate at partially desensitized AMPA receptors. The data were in strong agreement with the predictions of a model of transmitter diffusion from multiple release sites into a large synaptic cleft. Within the first millisecond after release, transmitter concentrations in the cleft fell below millimolar levels, causing the fastest parts of the EPSC to be shaped by channel kinetics. The slowest component was determined by the removal over tens of milliseconds of the final 10-100 microM glutamate by diffusion and uptake. The data and modeling indicate that transmitter uptake and cooperation between release sites are significant determinants of a slow "tail" of glutamate in the synaptic cleft. This slow clearance of glutamate is likely to limit postsynaptic receptor availability through desensitization.

Early and advanced glycosylation end products. Kinetics of formation and clearance in peritoneal dialysis

The chronic contact of glucose-containing dialysate and proteins results in the deposition of advanced glycation end products (AGEs) on peritoneal tissues in patients treated by peritoneal dialysis (PD), yet plasma levels of the AGE pentosidine are significantly lower in PD than in hemodialysis (HD). We measured glycation of peritoneal proteins in patients on PD over the time course of intraperitoneal equilibration of fresh peritoneal dialysate. The glycated content of peritoneal proteins (furosine method) was initially identical to plasma but increased 200% within 4 h due to in situ glycation as also demonstrated in vitro. In contrast, peritoneal proteins contained a 2-4 x greater content of the AGE pentosidine at all equilibrium time points. Plasma protein furosine content was identical in patients on PD and on HD. Fractionation by gel filtration of serum from patients on PD and HD revealed that > 95% of the pentosidine was linked to proteins > 10,000 mol wt; < 1% to proteins < 10,000 mol wt; and < 1%, free. Neither HD nor PD affected protein-bound pentosidine. The HD treatment decreased free and < 10,000 mol wt bound pentosidine. However clearance of protein-associated pentosidine by the peritoneal membrane may explain lower steady state levels in patients treated by PD.

Pharmacological evaluation of N-methyl-actinodaphnine, a new vascular alpha-adrenoceptor antagonist, isolated from Illigera luzonensis

The pharmacological activity of N-methyl-actinodaphnine, isolated from Illigera luzonensis, was determined by functional and binding experiments with peripheral tissues. In a functional study, N-methyl-actinodaphnine was a simple competitive antagonist of contractions elicited by phenylephrine (pA2 = 7.11) in rat thoracic aorta; it also competitively antagonised the clonidine-induced inhibition of the twitch response of rat vas deferens (pA2 = 5.01). In addition, [3H]inositol monophosphate formation caused by noradrenaline (3 microM) in rat isolated thoracic aorta was concentration dependently inhibited by N-methyl-actinodaphnine (1 and 10 microM); however, it had no effect on cyclic AMP and cyclic GMP contents. Additionally, N-methyl-actinodaphnine had extremely low affinity for thromboxane receptors, prostaglandin receptors, Ca2+ channels, muscarinic receptors, histamine receptors, beta-adrenoceptors, neurokinin and leukotriene receptors in vitro. However, N-methyl-actinodaphnine also possessed 5-hydroxytryptamine (5-HT) receptor blocking activity. Its potency for blocking 5-HT receptors was about 14 times less than that for blocking alpha 1-adrenoceptors. In binding experiments, N-methyl-actinodaphnine displaced biphasically the binding of 0.2 nM [3H]prazosin to cultured A10 cells. The selectivity for alpha 1-adrenoceptor subtypes was also investigated in rat vas deferens and spleens. The contractile response in rat vas deferens to noradrenaline was competitively inhibited by N-methyl-actinodaphnine with a pA2 value of 6.58; N-methyl-actinodaphnine also competitively antagonized the phenylephrine-induced contraction in rat spleen with a pA2 value of 7.38. These results indicate that N-methyl-actinodaphnine is a selective alpha 1-adrenoceptor antagonist. Furthermore, it is more selective for the alpha 1B- than for the alpha 1A-adrenoceptor subtype.