Structural determinants of cobrotoxin affect its mobility on sodium dodecyl sulfate polyacrylamide gel

In order to identify the structural determinants of cobrotoxin that caused its anomalous mobility in sodium dodecyl sulfate (SDS) gel, comparative studies on the capacities of cobrotoxin and its modified derivatives for binding with SDS were made. Cobrotoxin migrates faster in SDS gel after modification of Lys residues or carboxylated groups. However, the capacities of modified derivatives for binding with SDS molecules did not show a positive correlation with their electrophoretic mobilities. Moreover, it was found that the segment at positions 22-38 had the greatest capacity to bind with SDS than other segments of cobrotoxin, but guanidination of Lys residues of this peptide fragment did not significantly change its migration. These results suggest that the SDS-binding capacity of cobrotoxin is not solely responsible for its anomalous mobility in SDS gel, and that the effects may arise from the electrostatic interactions between Lys residue and carboxylated groups.

cDNA sequence analysis of a novel cardiotoxin-like protein from Taiwan banded krait

The cDNAs encoding a novel protein was constructed from the cellular RNA isolated from the venom glands of Bungarus multicinctus by reverse transcription-polymerase chain reaction. The deduced amino acid sequence of this novel protein contained 65 amino acid residues with 8 cysteine residues. Comparative sequence analysis showed that it was structurally related to cardiotoxin rather than neurotoxins. These results suggest that the venom of Bungarus multicinctus may contain cardiotoxin(s) which was not noticed before.

The essentiality of calcium ion in the enzymatic activity of Taiwan cobra phospholipase A2

In order to address the mechanism whereby Ca2+ wad crucial for the manifestation of the enzymatic activity of phospholipase A2 (PLA2), four divalent cations were used to assess their influences on the catalytic activity and the fine structures of Naja naja atra PLA2. It was found that substitution of Mg2+ or Sr2+ for Ca2+ in the substrate solution caused a decrease in the PLA2 activity to 77.5% or 54.5%, respectively, of that in the presence of Ca2+. However, no PLA2 activity was observed with the addition of Ba2+. With the exception of Mg2+, the nonpolarity of the 8-anilinonaphthalene-1-sulfonate (ANS)-binding site of PLA2 markedly increased with the binding of cations to PLA2. In the meantime, the accessibilities of Lys-6 (65) and Tyr-3 (63) toward trinitrobenzene sulfonate and p-nitrobenzenesulfonyl fluoride were enhanced by the addition of Ca2+, Sr2+, and Ba2+, but not by Mg2+. The order of the ability of cations to enhance the ANS fluorescence and the reactivity of Lys and Tyr residues toward modified reagents was Ba2+ > Sr2+ > Ca2+ > Mg2+, which was the same order as the increase in their atomic radii. These results, together with the observations that the ANS molecule binds at the active site of PLA2 and that Tyr-3, Lys-6, and Tyr-63 of PLA2 are involved in the binding with the substrate, suggest that the binding of Ca2+ to PLA2 induces conformational changes at the active site and substrate-binding site. However, the smaller atomic radius with Mg2+ or the bigger atomic radii with Sr2+ and Ba2+ might render the conformation improperly rearranged after their binding to PLA2 molecule.

cDNA sequence analysis and mutagenesis studies on the A chain of beta-bungarotoxin from Taiwan banded krait

The cDNA encoding the A chain of beta-bungarotoxin (beta-Bgt) was constructed from the cellular RNA isolated from the venom glands of Bungarus multicinctus (Taiwan banded krait). The deduced amino acid sequence encoding the A chain revealed that the determined chain was different from the known A chains (A1, A2, A3, A4, and A5). Nevertheless, the amino acid sequence and the cDNA sequence of the novel A chain were highly homologous with those of other A chains. The gene encoding the A chain of beta-Bgt was subjected to mutagenesis, and the Tyr-11, Cys-15, and Leu-72 of the A chain were substituted by Cys-11, Ser-15, and Cys-72, respectively. Instead of the six disulfide bonds observed with the A chain, the resulting mutant contained seven disulfide linkages in its molecular structure which simulated those of presynaptic PLA2 neurotoxins and PLA2 enzymes. However, the mutant did not exhibit a higher phospholipase activity than that noted with the recombinant A chain. These results seem to suggest that, in the absence of the B chain, the six pairs of disulfide bonds in the recombinant A-chain molecule are enough to maintain its active conformation for exerting the phospholipase activity.

Recurrence rate and risk factors for urinary calculi after extracorporeal shock wave lithotripsy

PURPOSE

We determined the recurrence rate after extracorporeal shock wave lithotripsy (ESWL*) and evaluated its associated risk factors, such as patient sex and age, volume of daily water intake, related diseases, family history of urinary calculi, number, burden and location of stones, residual stones after ESWL, serum uric acid level before ESWL and so forth.

MATERIALS AND METHODS

We conducted a retrospective study of 841 patients who underwent ESWL for primary treatment of urinary calculi between 1985 and 1987. Charts were reviewed for stone characteristics, outcomes and associated laboratory data. Followup 6 to 9 years later was done by mail and telephone interviews.

RESULTS

Followup data were available for 436 patients (52%). Overall, stones recurred in 51% of the 436 patients at a mean followup of 7.1 years. Late recurrences were common, and were noted in as many as 70% of the patients after 9 years. This rate is greater than what has been previously reported after other treatments. Cox regression analysis indicated that the major risk factors associated with recurrence were male gender (relative risk 1.406, p < 0.05) and multiple stones (relative risk 1.777, p < 0.05).

CONCLUSIONS

The frequent late recurrences support the speculation that ESWL might lead to greater recurrence rates. Therefore, the cost-effectiveness of ESWL versus other modalities for stone removal warrants more long-term evaluation.

Expression of Taiwan banded krait phospholipase A2 in Escherichia coli, a fully active enzyme generated by hydrolyzing with aminopeptidase

A cDNA encoding Bungarus multicinctus (Taiwan banded krait) phospholipase A2 was expressed in Escherichia coli. The expressed PLA2 contained a Met residue fused to the N-terminus of PLA2. The expressed protein was isolated from inclusion bodies of E. coli and subjected to refolding into its folded structure. Then the N-terminus Met residue of recombinant PLA2 was cleaved with aminopeptidase. The resulting recombinant PLA2 had the same amino acid composition and N-terminal sequence of native PLA2 and displayed the same CD spectra and pI value as native enzyme. Moreover, the recombinant PLA2 was indistinguishable from native PLA2 in enzymatic activity and antigenicity. These results suggest that a fully active PLA2 enzyme has been successfully expressed as its native form in snake venom.

The human serotonin 5-HT2C receptor: complete cDNA, genomic structure, and alternatively spliced variant

The complete 4775-nt cDNA encoding the human serotonin 5-HT2c receptor (5-HT2cR), a G-protein-coupled receptor, has been isolated. It contains a 1377-nt coding region flanked by a 728-nt 5'-untranslated region and a 2670-nt 3'-untranslated region. By using the cloned 5-HT2cR cDNA probe, the complete human gene for this receptor has been isolated and shown to contain six exons and five introns spanning at least 230 kb of DNA. The coding region of the human 5-HT2CR gene is interrupted by three introns, and the positions of the intron/exon junctions are conserved between the human and the rodent genes. In addition, an alternatively spliced 5-HT2CR RNA that contains a 95-nt deletion in the region coding for the second intracellular loop and the fourth transmembrane domain of the receptor has been identified. This deletion leads to a frameshift and premature termination so that the short isoform RNA encodes a putative protein of 248 amino acids. The ratio for the short isoform over the 5-HT2CR RNA was found to be higher in choroid plexus tumor than in normal brain tissue, suggesting the possibility of differential regulation of the 5-HT2CR gene in different neural tissues or during tumorigenesis. Transcription of the human 5-HT2CR gene was found to be initiated at multiple sites. No classical TATA-box sequence was found at the appropriate location, and the 5'-flanking sequence contains many potential transcription factor-binding sites. A 7.3-kb 5'-flanking 5-HT2CR DNA directed the efficient expression of a luciferase reporter gene in SK-N-SH and IMR32 neuro-blastoma cells, indicating that it contains a functional promoter.

Structural determinants of cobrotoxin for binding to an enzyme-linked-immunoassay plate

In order to assess the manner in which the structural state of a protein affects the results of an ELISA, the antigenic reactivities of cobrotoxin and reduced and S-carboxymethylated (RCM-) cobrotoxin with anti-RCM-cobrotoxin antibodies were studied. The results of competitive enzyme-linked immunoassay showed that the affinity of RCM-cobrotoxin for anti-RCM-cobrotoxin antibodies was higher than that of cobrotoxin. However, the cobrotoxin-coated wells had a greater reactivity towards anti-RCM-cobrotoxin antibodies than against RCM-cobrotoxin-coated wells. The lower reactivity observed with RCM-cobrotoxin-coated plates could be improved by adding 0.01% glutaraldehyde during the coating procedure. Studies on the antigenic structures of RCM-cobrotoxin showed that it contained an immunodominant epitope at residues 22-38. Moreover, the N-terminal and C-terminal regions of RCM-cobrotoxin encompassed other antigenic determinants which exhibited low reactivities towards anti-RCM-cobrotoxin antibodies. After removal of the antibodies against residues 22-38 of cobrotoxin from anti-RCM-cobrotoxin antibodies by passage through an affinity column, the remaining antibodies exhibited a similar reactivity towards cobrotoxin and RCM-cobrotoxin. The antibodies against residues 22-38 retained a little reactivity with the RCM-cobrotoxin-coated wells. These results suggest that the structural determinants of cobrotoxin and RCM-cobrotoxin for binding to the microtitre plates differ. Unlike RCM-cobrotoxin, the loop II structure of cobrotoxin encompassing residues 22-38 is not exclusively involved in the binding of cobrotoxin to microtitre plates.

The significance of tumour grade in predicting disease progression in stage Ta transitional cell carcinoma of the urinary bladder

OBJECTIVE

To determine the significance of tumour grade in predicting disease progression in stage Ta transitional cell carcinoma (TCC) of the urinary bladder.

PATIENTS AND METHODS

From August 1975 to January 1991, 140 patients (121 men and 19 women, mean age 64.2 years, range 30-83) with stage Ta TCC of the urinary bladder were treated at the Veterans General Hospital-Taipei by transurethral resection and post-operative adjuvant intravesical chemotherapy. There were 48 patients (34%) with grade 1, 78 patients (56%) with grade 2 and 14 patients (10%) with grade 3 tumours. Disease progression and muscle invasion were assessed during a mean follow-up of 74.3 months and related to grade, urine cytology and the number and location of tumours.

RESULTS

A total of 10 patients (7%) had tumour recurrence which invaded the muscle, of whom one had grade 1, six had grade 2 and three had grade 3 tumours. The patient with a grade 1 tumour developed muscle invasion within 16 months of surgery. The mean interval to the development of muscle invasion was 49.2 months in patients with grade 2 and 39.4 months with grade 3 tumour. In patients with stage Ta TCC, a grade 3 tumour was more likely to progress to muscle invasion (21%) than was a grade 1 (2.1%; P < 0.05) or grade 2 (7.7%; P < 0.05) tumour. One patient with a grade 2 and one patient with grade 3 tumour developed distant metastases without muscle invasion. Overall, the disease progression rate was 8.6% (12/140) in stage Ta TCC. Disease progression was more common with grade 3 (28.5%) than with grade 2 (9.0%; P < 0.05) and grade 1 (2.1%; P < 0.05) tumours.

CONCLUSION

Tumour grade may be used to predict disease progression after resection of stage Ta urinary bladder cancer. A higher grade of tumour was associated with a higher incidence of disease progression.

Testosterone enhances whereas estrogen inhibits calcium oxalate stone formation in ethylene glycol treated rats

PURPOSE

The present study was conducted to extend our earlier study on the role of testosterone in the pathogenesis of urolithiasis and to further investigate the influence of sex hormone on the pathogenesis of calcium oxalate stone.

MATERIALS AND METHODS

Adult Sprague-Dawley rats were divided into 9 groups, each containing 10 rats. Two groups of rats were left untreated and served as male and female controls. Another 7 groups of rats were fed a 0.5% ethylene glycol (EG) lithogenic diet for 4 weeks. Among them, 2 groups were male and female rats, 2 groups were castrated, 2 groups were castrated and then were subcutaneously implanted with testosterone, and 1 group of intact female rats was also subcutaneously implanted with testosterone. The stone and crystal deposits were examined by infrared spectrometer and polarizing and scanning electron microscope, respectively. Serum testosterone, creatinine and electrolytes and the renal excretion of, oxalate, citrate and creatinine were determined.

RESULTS

Subcutaneous implantation of exogenous testosterone restored calcium oxalate stone formation in castrated, EG-treated male rats (80%) and enhanced urolithiasis in castrated female rats receiving EG (40%). However, the testosterone effect was less striking in intact female rats fed EG (10%).

CONCLUSIONS

These data suggest that testosterone can promote and estrogen may inhibit calcium oxalate stone formation in EG-treated rats.

Urinary bladder endometriosis: a report of two cases

Endometriosis of the urinary tract is uncommon, and the most common site of involvement is urinary bladder. Two cases of endometriosis of urinary bladder are presented. The first patient, a 39-year-old woman, complained of dysuria during menstruation and the other 37-year-old woman suffered from intermittent gross hematuria. Pre-operative examinations included ultrasonography, computed tomography and cystoscopic biopsy. Case 1 was in premenopausal status, but the serum estrogen level of case 2 was in postmenopausal status because she was given no exogenous estrogen after previous bilateral salpingo-oophorectomy. Endometriosis of urinary bladder rarely occurs in postmenopausal woman without exogenous estrogen replacement. Case 1 received danazole treatment after transurethral resection of bladder tumor and case 2 received partial cystectomy after transurethral resection of bladder tumor. The patients were followed 36 and 4 months, respectively, and the symptoms kept improving during this period.

Chemical modification of notexin from Notechis scutatus scutatus (Australian tiger snake) venom with pyridoxal-5'-phosphate

Notexin from Notechis scutatus scutatus snake venom was subjected to Lys modification with pyridoxal 5'-phosphate (PLP), and one major modified derivative was purified on a cation-exchanger SP-8HR column. The results of amino acid analysis and sequence determination revealed that only 2 Lys residues at positions 82 and 115 out of 11 Lys residues in notexin were modified. The incorporation of PLP into the protein was accompanied by the loss of 53% lethal toxicity, but the modified notexin showed an about 1.2-fold increase in enzymatic activity. However, the secondary structure of the toxin molecule did not significantly change after modification with PLP as revealed by the CD spectra, and the antigenicity of PLP derivative remained unchanged. The modified derivative retained its affinity for Ca2+, indicating that the modified Lys residues did not participate in Ca2+ binding. These results indicate that modification of Lys residues causes a differential effect on the enzymatic activity and lethal toxicity of notexin, and suggest that notexin might possess two functional sites, one responsible for the catalytic activity and the other associated with its lethal effect.

cDNA sequence analysis and expression of cardiotoxin V and a new cardiotoxin VII from Naja naja atra (Taiwan cobra)

The cDNAs encoding cardiotoxin V and a new cardiotoxin VII were constructed from the cellular RNA isolated from the venom glands of Naja naja atra by reverse transcription-polymerase chain reaction. Although 95% nucleotide sequence homology was observed with the two cardiotoxins, there were nine amino-acid substitutions between cardiotoxin V and cardiotoxin VII. The cardiotoxins were subcloned into the expression vector pET 20b(+) and transformed into BL21(DE3) E. coli strain. The expressed protein was isolated from the inclusion bodies of E. coli, and purified by reverse-phase high-performance liquid chromatography. The purified recombinant cardiotoxin showed immunoreactivity with anti-cardiotoxin III antibodies as revealed by immunoblot analysis.

The interaction of 8-anilinonaphthalene-1-sulfonate with His-47 of Taiwan cobra phospholipase A2 perturbing by the binding of calcium ion

The 8-anilinonaphthalene-1-sulfonate (ANS) fluorescence intensity of ANS-Naja naja atra (Taiwan cobra) phospholipase A2 (PLA2) complex increased with the addition of Ca2+, but the observed fluorescence enhancement markedly decreased after methylation of His-47 in PLA2 molecule. However, the binding affinities of methylated PLA2 for ANS and Ca2+ were similar to or even greater than those observed with native PLA2. These results, together with the finding that ANS electrostatically interacted with His-47 of PLA2, suggest that the increase in the intensity of ANS fluorescence upon the addition of Ca2+, in part, arises from the ionic interaction of His-47 with ANS being perturbed by the binding of Ca2+.

cDNA sequence analysis and expression of the a chain of beta-bungarotoxin from Bungarus multicinctus (Taiwan banded krait)

The cDNA encoding the A chain of beta-bungarotoxin (beta-Bgt) was constructed from the cellular RNA isolated from the venom glands of Bungarus multicinctus (Taiwan banded krait). The deduced amino acid sequence encoding the A chain revealed that the determined one was different from the known A chains (A1, A2, A3 and A4). Nevertheless, the amino acid sequence and cDNA sequence of the new A chain (A5) was highly homologous with those of other A chains. The A5 chain was subcloned into the expression vector pT7-7 and transformed into BL21(DE3) E. coli strain. The expressed protein was isolated from the inclusion bodies of E. coli, and the refolded A chain was purified by reversed phase high performance liquid chromatography. The purified recombinant A chain exhibited an about 16% phospholipase activity of beta-Bgt. These results strongly suggest that the A chain is an active subunit responsible for the phospholipase activity of beta-Bgt.

The functional involvement of Lys-38 in the heavy subunit of rat kidney gamma-glutamylcysteine synthetase: chemical modification and mutagenesis studies

Rat kidney gamma-glutamylcysteine synthetase (gamma GCS) was inactivated by reaction with trinitrobenzene sulfonate (TNBS), and the reaction followed pseudo-first-order kinetics. Inactivation kinetics revealed that only one of the amino acid residues modified by TNBS was essential for gamma GCS activity. The addition of 10 mM Mg2+ to the TNBS inactivation reaction resulted in a 16-fold increase in the rate of inactivation. Chromatographic analysis on the tryptic hydrolyzates of trinitrophenylated (TNP) derivatives showed that Lys-38 in the gamma GCS heavy subunit was significantly modified in the presence of Mg2+. In contrast to small changes in the catalytic properties observed by mutation of Lys-38 to Arg, the mutants K38N and K38E had a marked decrease in enzymatic activity and about twofold increase in Km for glutamate. These results suggest that the positively charged Lys-38 may be involved in the binding of glutamate to gamma GCS.

Dynamic infusion cavernosometry and cavernosography (DICC) in the evaluation of vasculogenic impotence

BACKGROUND

This study was conducted to find more accurate physiological assessment of the penile vascular status in impotent patients.

METHODS

Twenty-two males, aged 25-76 years (mean 54.0 years) with possible underlying vascular causes of impotence, had dynamic infusion cavernosometry and cavernosography (DICC) examination to ascertain the arterial and/or venous insufficiency in the penis. Prostaglandin E1 20 micrograms was injected intracavernously in this 4-phase study.

RESULTS

No side effect or complication was noted during or after the examination in all 22 patients. During the phase 1 test, the mean resting intracavernous pressure (ICP) was 6.8 +/- 3.6 mmHg and the mean plateau ICP after PGE1 injection was 47.2 +/- 23.9 mmHg. The mean ratio of plateau ICP to mean arterial pressure was 50.2 +/- 23.4%. In the phase 2, the mean ICP determined 30 seconds after cessation of saline infusion without and with perineal compression was 65.3 +/- 26.8 mmHg and 129.1 +/- 26.2 mmHg, respectively. The mean ICP decay from 150 mmHg was 84.7 +/- 26.8 mmHg. The mean systolic pressure of each cavernous artery, 87.6 +/- 18.9 mmHg and 93.6 +/- 17.6 mmHg in left and right side, respectively, was found during phase 3 evaluation. The mean ratio of systolic pressure of each cavernous artery to brachial artery (cavernous-brachial index, CBI) was 70.1 +/- 12.7% and 75.1 +/- 11.5% in left and right side, respectively. Six patients with CBI greater than 75% had normal Doppler duplex sonography (diameter of cavernous artery greater than 0.9 mm and peak flow velocity greater than 25 cm/sec). Cavernosography in phase 4 evaluation showed venous leakage in 20 of 22 patients (90.9%) with ICP decay greater than 60 mmHg. Two patients with ICP decay less than 45 mmHg were found to have no venous leakage.

CONCLUSIONS

The cavernous-brachial index is usually less than 75% in penile arterial insufficiency. The patients with ICP decay from 150 mmHg greater than 60 mmHg would have penile venous leakage demonstrated in the cavernosography. The results of cavernosometry are highly correlated with cavernosography. Our results suggest that DICC may provide a good examination for more physiological assessment and accurate diagnosis of vasculogenic impotence.

The essentiality of His-47 and the N-terminal region for the binding of 8-anilinonaphthalene-1-sulfonate with Taiwan cobra phospholipase A2

The binding of the apolar fluorescent dye 8-anilinonaphthalene-1-sulfonate (ANS) to Naja naja atra phospholipase A2 (PLA2) as well as the enhancement of ANS fluorescence of the PLA2-ANS complex decreased with increasing pH in a pH range from 3 to 9. These pH-dependent curves can be well interpreted as the perturbation of an ionizable group with pK value of 5.8, which was assigned as His-47 in the active site of PLA2. The ionizable group with pK 5.8 was no longer observed after methylation of His-47, supporting the idea that the pH dependence of ANS binding arose from an electrostatic interaction between His-47 and the bound ANS. Removal of the N-terminal octapeptide of PLA2 caused a precipitous drop in the capability of PLA2 for binding with ANS and enhancing ANS fluorescence, reflecting that the integrity of the N-terminal region was essential for maintaining the hydrophobic character of the ANS-binding site. However, the nonpolarity of the ANS-binding site in the N-terminus-removed derivative was still partially retained at low pH, but was completely lost at high pH. Evidently, the N-terminal region plays a more crucial role in ANS binding at high pH than at low pH. These results indicate that hydrophobic interaction as well as electrostatic interaction are involved in the binding of ANS to PLA2, and that the relative contributions of both interactions in ANS fluorescence enhancement may be different under different pH.

The structural elements of phospholipase A2 affecting the enhancement of 8-anilinonaphthalene-1-sulfonate fluorescence

The binding of the apolar fluorescent dye 8-anilinonaphthalene-1-sulfonate (ANS) to Naja naja atra and Bungarus multicinctus phospholipase A2 (PLA2) as well as the ANS fluorescence enhancement of PLA2-ANS complexes were pH-dependent. However, the pH-dependent curves and the ionizable groups perturbed by the binding of ANS were essentially different for the two PLA2 enzymes. Methylation of His residue or removal of the N-terminal octapeptide made the ANS fluorescence of PLA2-ANS complexes become less sensitive to pH changes. Moreover, the N-terminus-removed derivatives showed the same fluorescence-pH profiles. These results, together with the findings that the His residue and the N-terminal residues might locate around the ANS-binding site, suggested that the His residue and N-terminus of the two PLA2 enzymes may interact electrostatically with the bound ANS, and that ionization of these residues should appreciably affect the ANS fluorescence.

cDNA sequence analysis and expression of cardiotoxins from Taiwan Cobra

The cDNAs encoding cardiotoxins I, III and N were constructed from the cellular RNA isolated from the venom glands of Naja naja atra by reverse transcription-polymerase chain reaction. A high degree of sequence homology was observed with the three cardiotoxins. The cardiotoxins were subcloned in the expression vector pET 20b(+) and transformed in BL 21(DE3) E. coli strain. The expressed protein was isolated from the inclusion bodies of E. coli and purified by reversed phase high performance liquid chromatography. The purified recombinant cardiotoxin III showed an immunoreactivity with anti-cardiotoxin III antibodies as revealed by immunoblot analysis.

Adjuvant methotrexate, vinblastine and cisplatin chemotherapy for invasive transitional cell carcinoma: Taiwan experience

PURPOSE

The feasibility of adjuvant cisplatin, methotrexate and vinblastine chemotherapy was evaluated in Taiwanese patients with invasive transitional cell carcinoma at high risk for recurrence.

MATERIALS AND METHODS

We assigned 56 patients with high risk transitional cell carcinoma (vascular or lymphatic invasion in the primary tumor, poorly differentiated stage P2, P3, P4 or N+ and M0) to receive adjuvant chemotherapy after radical urological surgery. The chemotherapy consisted of 40 mg./m.2 methotrexate and 4 mg./m.2 vinblastine on days 1 and 8, and 100 mg./m.2 cisplatin on day 2 given in 6 courses at 21-day intervals.

RESULTS

Median followup was 44 months. An average of 4.63 cycles of chemotherapy was administered. The median actual survival was 44 months, and the 1 and 3-year survival probabilities were 92% and 50%, respectively. The median disease-free survival was 15.5 months, and the 1 and 3-year disease-free survival probabilities were 66% and 28%, respectively. Only 5 (9%) and 1 (2%) patients had grades 3 and 4 leukopenia, respectively, and none died of sepsis.

CONCLUSIONS

The use of adjuvant cisplatin, methotrexate and vinblastine chemotherapy in patients with invasive transitional cell carcinoma at high risk for recurrence is feasible with tolerable toxicity but randomized controlled trials will be required to assess the benefit.

A porcine model for renal hemodynamic study during laparoscopy

Laser Doppler flowmetry (LDF) is a sensitive method for the measurement of microvascular blood flow in tissue. The method has been found useful for estimating skin, liver, or gastrointestinal blood flow. Whether it can be applied laparoscopically and whether it is able to measure the intraparenchymal blood flow of an intraabdominal organ is still unknown. In a pilot study, 6 pigs received a laparotomy for placement of a 19-gauge LDF needle probe into the renal parenchyma. Three different locations of the lower pole kidney were chosen for the blood flow measurement. The reliability of using the instrument to measure the renal tissue blood flow was assessed by comparison of the results of renal arterial blood flow obtained from a well-established methodology--ultrasonic Doppler flowmetry. Recordings were taken following (a) intravenous administration of 0.005 mg/kg norepinephrine, (b) manual compression of the suprarenal aorta, and (c) intravenous injection of a lethal dose of phenobarbital (50 mg/kg). Measurements of LDF were possible in all kidney units. The renal tissue perfusion detected by LDF correlated excellently with the renal arterial blood flow under different renal perfusion pressures. The feasibility of using LDF probe to measure the renal tissue perfusion in a laparoscopic model was then assessed in 15 pigs. Under pneumoperitoneum, the right kidneys were approached transperitoneally with the animal in the decubitus position. A total of three trocars were used. The peritoneum and Gerota's fascia were incised and the LDF needle probe was manipulated and inserted by an endoforceps into the renal tissue via a 5-mm trocar. The insertion of the LDF needle probe was technically feasible in all 15 kidney units, and the depth of insertion could be adjusted under direct vision. Baseline values for the renal cortical and renal medullary blood flow were 50.1 +/- 17.7 and 8.8 +/- 3.3 ml/min/100 g tissue, respectively. Spatial variations of the LDF measurements averaged 6%, and temporal variations over 15 min averaged 5%. Four additional hemodynamic parameters were simultaneously recorded, including left carotid artery blood flow, aortic blood pressure, inferior vena caval pressure, and intraabdominal pressure. It appears that systemic and renal hemodynamic parameters can be monitored reliably and continuously in the porcine model. This method allows further information concerning hemodynamic changes and safety of laparoscopy to be obtained.

Chemical modification of cationic residues in toxin a from king cobra (Ophiophagus hannah) venom

The cationic groups of arginine and lysine residues in alpha-neurotoxin, Toxin a, isolated from king cobra (Ophiophagus hannah) venom were subjected to modification with trinitrobenzene sulfonate (TNBS) and p-hydroxyphenylglyoxal (HPG), respectively. The trinitrophenylated (TNP) derivatives of Toxin a at Lys-10, 56, or 71 showed approximately 25% residual lethality, and modifications on Lys-10 and 56 or Lys-10 and 50 resulted in a decrease of lethality by 84% and 86%, respectively. Modifications on Arg-34, 37, and 70 and Arg-34, 37, and 72 in Toxin a caused a decrease in lethality by 92% and 93%, respectively, and it almost completely lost its lethality and binding activity to nicotinic acetylcholine receptor (nAChR) when all four arginine residues were modified. These results indicate that in addition to the cationic residues on loop II (Arg-34, 37), loop III (Lys-50, 56), and the C-terminal tail (Arg-70, 72; Lys-71), Lys-10 on loop I is also related to the neurotoxicity of Toxin a.

Laparoscopic ligation of bilateral spermatic varices under epidural anesthesia

Feasibility and safety of laparoscopic ligation of bilateral internal spermatic varices under epidural anesthesia were assessed in 11 patients. Another 11 patients undergoing the same procedure under ventilation-assisted anesthesia served as controls. Patients in both groups belonged to the American Society of Anesthesia functional class I. Arterial blood analyses were obtained (1) in the horizontal supine position; (2) in the 15 degrees Trendelenburg position; (3) at 15 min after carbon dioxide pneumoperitoneum insufflation, and (4) at 15 min after desufflation in the supine position. In the epidural anesthesia group arterial blood parameters and respiratory rate remained stable in the Trendelenburg position. After intraperitoneal insufflation of carbon dioxide for 15 min, the arterial carbon dioxide level increased from 40.1 +/- 2.2 to 42.1 +/- 2.6 mm Hg, the respiratory rate increased from 17.0 +/- 1.4 to 20.6 +/- 1.2/min, the blood pH value decreased from 7.386 +/- 0.027 to 7.355 +/- 0.034, all values showing statistically significant differences. These changes returned to the preinsufflation level 15 min after release of the pneumoperitoneum. The above-mentioned parameters remained unchanged under the pneumoperitoneum by assisted ventilation in the control group. The mean time of surgery was similar in both groups: 82 and 90 min for the groups having general and epidural anesthesia, respectively. All laparoscopic procedures were accomplished successfully under general anesthesia. However, failure to ligate the internal spermatic varices occurred in 3 patients under epidural anesthesia, mainly due to patient intolerance to abdominal distension. The operation was continued under intubated general anesthesia for relaxing the abdominal muscle to provide an adequate working space. In 8 patients being successfully operated under epidural anesthesia, 5 experienced mild but tolerable abdominal distension; 2 complained of shoulder pain intraoperatively. Although laparoscopic ligation of internal spermatic varices could be accomplished in some patients under epidural anesthesia, it carried a high failure rate, more intraoperative morbidity, and significant arterial blood gas alterations. Routine ventilation-assisted anesthesia is suggested for therapeutic laparoscopy even for an easy procedure such as the ligation of the internal spermatic varices.