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.

Effect of orchiectomy on the alpha adrenergic contractile response of dog prostate

PURPOSE

To investigate the effect of androgen deprivation on the alpha-adrenergic contractile response of the dog prostate using both in vitro and in vivo methods.

MATERIALS AND METHODS

In vitro muscle bath study: One month after surgery, responses to KCl (120 mM.) and norepinephrine (10(-8) to 10(-3)M.) of prostatic tissue strips (of the same size) from castrated (n = 6) and sham-operated (n = 6) adult mongrel dogs were determined. In vivo study: Before and 1 month after surgery, the intraprostatic urethral pressure response to intravenous norepinephrine administration of 6 castrated and 5 sham-operated adult dogs was examined.

RESULTS

(1) Before castration the serum level of testosterone was 1.24 +/- 0.2 ng./ml.; 1 month after castration, it had dropped to an undetectable level. (2) Histological examination of the prostates from castrated animals revealed profound atrophy of glandular tissue with a relatively increased stromal tissue component in each section. (3) In vitro study: The contractile responses to KCl and norepinephrine of individual prostate strips (same size) from castrated animals were significantly higher than control. However, if the response to norepinephrine was normalized to the response to KCl, there was no significant difference in response to norepinephrine between the 2 groups. In addition, the ED50 of the norepinephrine-stimulated contractile response was not changed by castration. (4) In vivo study: There was no significant change in intraprostatic urethral pressure response to intravenous norepinephrine administration after orchiectomy.

CONCLUSIONS

The results of this study show that the sensitivity of the alpha-adrenergic contractile response of the dog prostate is not affected by androgen deprivation, nor is alpha-adrenergic contractile activity of the dog prostate regulated by androgen.

The impact of pneumoperitoneum, pneumoretroperitoneum, and gasless laparoscopy on the systemic and renal hemodynamics

BACKGROUND

The use of therapeutic laparoscopy has become widespread recently. It is important to assess the effects of gaseous and gasless laparoscopy on systemic and renal hemodynamics.

STUDY DESIGN

A prospective controlled animal study was performed on 40 well-hydrated pigs. Systemic and renal hemodynamics were monitored during peritoneal insufflation, retroperitoneal insufflation, and abdominal wall lifting for a period of two hours. A laser Doppler flow meter was applied laparoscopically to measure the renal cortical tissue perfusion.

RESULTS

Peritoneal insufflation of carbon dioxide to a pressure of 15 mm Hg elicited transient elevations of the aortic pressure and carotid arterial blood flow. Unilateral pneumoretroperitoneum caused a smaller change on systemic hemodynamics. Pneumoperitoneum and pneumoretroperitoneum caused oliguria. Superficial renal cortical blood flow reduction decreased by an average of 60 percent in the compressed kidney, and blood flow returned to the pre-insufflation level after the pressure was released. A gradual decrease of tissue perfusion in the contralateral kidney and a concomitant gradual increase of the intra-abdominal pressure were observed when pneumo-retroperitoneum was maintained for two hours. No significant changes in urinary output and in systemic and renal hemodynamics were found when the abdominal wall was lifted up with a force equivalent to 15 mm Hg.

CONCLUSIONS

Significant systemic and renal hemodynamic changes were elicited in gaseous but not in gasless laparoscopy, which may explain the decreased urinary output observed during gaseous laparoscopy. Pneumoperitoneum caused greater systemic and renal hemodynamic alterations than pneumoretroperitoneum; however, the effects were transient and reversible after a period of two hours.

Femoral neuropathy after pelvic surgery

Femoral neuropathy is an uncommon complication following pelvic surgery. We report on 2 cases of femoral nerve injury after pelvic surgery: 1 patient received radical cystectomy due to invasive transitional cell carcinoma of the urinary bladder, and the other patient had a transurethral resection of the bladder and received exploration and biopsy of a tumor mass over the right sacroiliac joint area. Pathogenesis and prevention of the complication of femoral neuropathy are discussed in the following report.

Characterization of epitopes in native and unfolded cobrotoxin: evidence of an immunodominant C-terminal region related to the production of precipitating and non-precipitating antibodies against cobrotoxin

Rabbits hyperimmunized with cobrotoxin from Taiwan cobra venom produced non-precipitating as well as precipitating antibodies. Both antibody preparations exhibited higher affinity for native cobrotoxin than for reduced and S-carboxymethylated (RCM) cobrotoxin. This indicated that the epitope structures in cobrotoxin are mostly conformation-dependent. In order to identify the conformational epitopes, native cobrotoxin was hydrolyzed with acid protease A, and 12 peptides were obtained on HPLC. Three peptide fragments, AP-10, AP-11, and AP-12, showed pronounced antigenicities toward precipitating as well as non-precipitating antibodies. AP-10, AP-11, and AP-12 contained a common segment in the C-terminal region of cobrotoxin, residues 43 to 62, with intact disulfide linkages. Complete removal of the C-terminal antibodies from antisera and precipitating antibodies on a C-terminal segment-Sepharose affinity column resulted in the loss of their precipitability with cobrotoxin, whilst restoration of precipitability was observed on the addition of the C-terminal antibodies to the C-terminal antibody-depleted antisera and precipitating antibodies. Studies on the antigenic structures of RCM-cobrotoxin revealed that RCM-cobrotoxin contains an immunodominant epitope at positions 22-38. The N-terminal and C-terminal regions of RCM-cobrotoxin encompass other epitopes which exhibit low reactivities toward anti-RCM-cobrotoxin antibodies. However, no precipitated antigen-antibody complexes were observed with the mixture of anti-RCM-cobrotoxin antibodies and RCM-cobrotoxin. These results suggest that the inherently different immunogenicities with different segments might affect the precipitabilities of the resulting antibodies, and that the notable immunogenecity of the C-terminal region is related to the production of precipitating and non-precipitating antibodies against cobrotoxin.

Defective mitochondrial oxidative phosphorylation in varicocele-bearing testicles

OBJECTIVES

Our previous study revealed a decreased blood flow in varicocele-bearing testicles. For further understanding of the possible mechanism of varicocele-induced infertility, we investigated the changes in energy metabolism in varicocele-bearing testicles.

METHODS

Partial ligation of the left renal vein was performed in 40 Wistar rats to induce dilation of the internal spermatic vein, and sham operations were performed in 20 other age-matched Wistar rats serving as controls. Orchiectomy was done at 1, 2, 4, and 6 months after induction of varicocele (or sham operation) in both groups. The histologic changes in the testicles were evaluated under the light microscope. The concentration of adenine nucleotides was determined by high-performance liquid chromatography, and various enzyme activities of mitochondria were determined by a spectrophotometer.

RESULTS

Histologic studies of varicocele-bearing testicles showed a lower Johnsen score (8.5 +/- 0.7 versus 9.3 +/- 0.5) and a decreased mean testicular tubular diameter (280.0 +/- 3.2 versus 295.0 +/- 1.4 microns) compared with the testicles in the sham-operated group. The energy charge decreased from 0.71 +/- 0.04, 0.70 +/- 0.03, 0.69 +/- 0.06, and 0.64 +/- 0.03 to 0.62 +/- 0.08, 0.59 +/- 0.05, 0.58 +/- 0.05, and 0.56 +/- 0.02 at 1, 2, 4, and 6 months, respectively. The reduced nicotinamide-adenine dinucleotide-cytochrome c reductase activities were decreased from 136.6 +/- 4.9, 127.3 +/- 10.7, 121.6 +/- 7.8, and 118.9 +/- 8.5 to 96.3 +/- 13.9, 95.6 +/- 27.8, 88.3 +/- 13.8, and 80.4 +/- 8.7 nmol/min/mg of protein, respectively; the succinate-cytochrome c reductase activities were decreased from 50.4 +/- 2.7, 49.0 +/- 4.7, 49.6 +/- 7.1, and 42.6 +/- 1.6 to 40.3 +/- 7.3, 41.0 +/- 11.5, 40.2 +/- 5.7, and 32.0 +/- 1.3 nmol/min/mg of protein, respectively; and the cytochrome c oxidase activities were decreased from 361.2 +/- 23.4, 350.3 +/- 25.5, 223.5 +/- 12.9, and 194.1 +/- 18.3 to 253.7 +/- 32.9, 256.4 +/- 38.8, 178.2 +/- 15.7, and 147.1 +/- 17.2 nmol/min/mg of protein at 1, 2, 4, and 6 months, respectively.

CONCLUSIONS

We thus suggest that defective energy metabolism plays an important role in the impairment of spermatogenesis of varicocele-bearing testicles.

The subjective assessment and pressure-flow study of outcome of surgical treatment for patients with prostatism and high voiding pressure

BACKGROUND

In 1992, the International Continence Society (ICS) began to conduct an international multicenter study to correlate the symptoms and urodynamics in patients with BPH. Our institute was invited to participate this ICS-BPH study, and the preliminary (phase I) results have revealed poor correlation between preoperative symptoms and parameters of the pressure-flow study. This phase II study continued the phase I ICS-BPH study to assess the changes of subjective symptoms and objective parameters of pressure-flow study before and after TURP.

METHODS

Fifty-two patients with prostatism, aged from 56 to 80, were evaluated using the ICS-BPH questionnaire, free urine flow rate and pressure-flow study. According to the criteria of maximum urine flow rate (Qmax) 15 ml/sec and voiding intravesical pressure at Qmax (Pves at Qmax) 100 cm H2O, low flow-high pressure (LFHP) was proved in 20 patients (38%), high flow-high pressure (HFHP) in 22 (42%), low flow-low pressure (LFLP) in 3 (6%), and high flow-low pressure (HFLP) in 7 (14%). Transurethral resection of the prostate (TURP) was performed for 33 of 42 patients with high voiding pressure (LFHP and HFHP groups).

RESULTS

The weight of the TURP specimen was 28 +/- 6.3 gm. Sixteen patients repeated the questionnaire and pressure-flow study 9.0 +/- 2.1 months after surgery. Both irritative and obstructive symptom scores decreased in 15 (94%) of the 16 patients (p < 0.001). The opening intravesical pressure (openPves) and Pves at Qmax improved from 136 +/- 34 and 124 +/- 30 cm H2O preoperatively to 89 +/- 25 and 94 +/- 22 cm H2O postoperatively respectively (p < 0.004). However, UFRmax, 16.7 +/- 6.0 ml/sec preoperatively and 19.3 +/- 6.4 postoperatively, showed no statistical difference. If the HFHP and LFHP groups were compared separately, the degree of improvement in symptomatology or parameters of pressure-flow study was similar, although changes in HFHP group appeared more evident. UFRmax in LFHP group changed significantly from 11.9 +/- 2.8 preoperatively to 22.1 +/- 6.7 ml/sec postoperatively. For the patients with high flow obstruction (HFHP group), although UFRmax did not increase after TURP, the symptom score, openPves and Pves at Qmax, decreased as much as the LFHP group did.

CONCLUSIONS

Based on the analysis of the pressure flow study, TURP not only offers an advantage to the patient with classical obstruction (LFHP group), but also to patients with high flow obstruction (HFHP group). However, this does not suggest that a pressure-flow study should be performed routinely for a male with prostatism. It is advised only for patients with Qmax > 15 ml/sec but exhibiting typical symptoms.

Direct needle insufflation for pneumoretroperitoneum: anatomic confirmation and clinical experience

OBJECTIVES

The feasibility and safety of direct needle insufflation to create pneumoretroperitoneum was assessed by an imaging study and clinical experience.

METHODS

A total of 10 patients without previous retroperitoneal surgery or diseases received computed tomography scans of the retroperitoneum 2 cm above the iliac crest. Distances between quadratus lumborum and colon (Q-C distance) were measured in the supine and lateral positions. Changes of Q-C distance were calculated when the patient was changed from the supine to the lateral position. Operative charts on 38 retroperitoneoscopic procedures were collected prospectively to assess complications related to direct needle insufflation, which was performed by inserting a 14 G Veress needle blindly along the posterior axillary line 2 cm above the iliac crest.

RESULTS

Q-C distance increased from 8.7 to 27.3 mm (left side) and 4.6 to 18.1 mm (right side) when the patient was changed from the supine to the lateral position, both P values < 0.05. An average distance of 23 mm between colon and quadratus lumborum was found when patients were lying laterally. The misplacement of a Veress needle was encountered in 1 patient, in which a prefascia insufflation resulted in conversion of the endoscopic procedure. Needle puncture caused no visceral or great vessel injury.

CONCLUSIONS

Significant anterior movement of the colon was found when patients were changed from the supine to the lateral position. It provided a window for inserting the Veress needle blindly into the retroperitoneum. The high success rate (97%) and low complication rate of direct needle insufflation were found in actual clinical applications. We considered needle insufflation a safe and effective method of establishing a pneumoretroperitoneum for any retroperitoneoscopic procedure.

Does prediction of epitopes from the primary structure of a protein represent the epitope in the native structure? A study using cobrotoxin

In contrast to observations made with S. aureus V8 protease-digest hydrolysates, the antigenic structures of reduced and S-carboxymethylated (RCM)-cobrotixin were notably affected following hydrolysis of RCM-cobrotoxin with chymotrypsin. The peptide separated from the V8 protease-digest hydrolysates with a sequence at positions 22-38 of cobrotoxin exhibited a nearly equal reactivity toward the anti-RCM-cobrotoxin antibodies as RCM-cobrotoxin. Chymotryptic cleavage on this segment caused a precipitous drop in the antigenicity of RCM-cobrotoxin. Alternatively, the N-terminal and C-terminal regions of RCM-cobrotoxin encompassed other antigenic determinants which exhibited low reactivities toward anti-RCM-cobrotoxin antibodies. The epitope structures of RCM-cobrotoxin are in line with those predicted from the hydrophobicity profile of cobrotoxin, but the notably immunoreactive region in the C-terminal region of native toxin molecule (Ref. 1) cannot be predicted from analysis of its primary structure. Moreover, RCM-cobrotoxin had a superior reactivity toward anti-RCM-cobrotoxin antibodies than cobrotoxin did. These results indicate that the epitope structures in RCM-cobrotoxin and cobrotoxin are different.

Structure of the gene for the catalytic subunit of human DNA polymerase delta (POLD1)

We have isolated genomic DNA clones covering the gene for human DNA polymerase delta catalytic subunit (POLD1) and its 5' flanking sequence. This gene is divided into 27 exons and is distributed over at least 32 kb of DNA. The exons and most of the introns are relatively small. The sizes of the exons range from 55 to 201 bp. Seven introns are smaller than 100 bp. Intron 1 is the largest intron, with a size of greater than 10 kb. All of the intron-exon junctions match well with the reported consensus sequences. Multiple copies of the Alu repetitive sequence and the variable number of tandem repeats were found in several introns. Transcription of POLD1 appears to initiate at multiple sites. The major start site was 53 nucleotides upstream of the ATG start codon. The sequence of the promoter and upstream DNA is G+C rich and does not contain a TATA sequence. Several potential transcription factor-binding sites, including the AP2-, CTF-, Ets1-, GCF-, MBF-1-, NF-E1-, and Sp1-binding sites, were found in this region. A 1.8-kb pol delta promoter DNA directed the expression of a luciferase reporter gene when transfected into HeLa cells.

Purification and characterization of a novel phospholipase A2 from king cobra (Ophiophagus hannah) venom

A novel phospholipase A2, designated as Oh-DE-2, was isolated from the venom of Ophiophagus hannah (king cobra) by successive chromatography on SP-Sephadex C-25, DE-52, and Q-Sepharose columns. Oh-DE-2 with pI 5.1 showed an apparent molecular weight of 14 kD as revealed by SDS-PAGE and gel filtration. The amino acid sequence was homologous with those of PLA2S from Elapidae venoms. Oh-DE-2 was effectively inactivated by p-bromophenacyl bromide, indicating that the conserved His-48 is essential for its enzymatic activity. However, modification of the conserved Trp-19 did not cause a precipitous drop in the enzymatic activity of Oh-DE-2 as observed with PLA2S from Naja naja atra and Bungarus multicinctus venoms. A quenching study showed that the microenvironment of Trp in Oh-DE-2 was inaccessible to acrylamide, iodide, or cesium, a finding which was different from those observed with PLA2S from N. naja atra and B. multicinctus venoms. These results might suggest that, unlike other PLA2 enzymes, Trp-19 in Oh-DE-2 is not directly involved in its enzymatic mechanisms.

Laparoscopic nephrolysis for chyluria: case report of long-term success

Laparoscopic nephrolysis was performed in an 81-year-old man with recurrent chyluria. A total of five trocars were used for approaching the lymphatic ducts over the right ureter and renal hilum. The lymphatic ducts identified were easily ligated under laparoscopic magnification. The recovery of this patient was quick and uneventful. The follow-up urinalysis for chyle was negative, and his serum albumin concentration increased from 3.0 g/dL to 4.2 g/dL at 2 years postoperatively. This case report attests to the long-term efficacy of a laparoscopic approach to ligation of lymphatic fistulas for the treatment of recalcitrant chyluria.

Role of amino and carboxyl groups of cobrotoxin in the conformational stability and the interaction with acetylcholine receptor

To study the functional involvements of the common interaction of the Leu-1 alpha-amino group and Asp-58 in cobrotoxin, the lysine epsilon-amino groups of cobrotoxin were initially guanidinated with o-methylisourea. The alpha-amino group of Leu-1 was them modified with TNBS after the guanidination of cobrotoxin. Both modified derivatives displayed no significant changes in the secondary structure and antigenicity of cobrotoxin, whereas the binding affinity for nicotinic acetylcholine receptor (nAChR) was pronouncedly decreased when Leu-1 was modified. Six out of seven free carboxyl groups and the remaining buried Glu-21 carboxyl group of cobrotoxin were modified with glycine methyl ester in the absence and presence of guanidine HCl, respectively. Alternation in the beta-sheet secondary structure of cobrotoxin was observed with the carboxyl-group modified derivatives, which caused a decrease in the binding activity of the toxin molecule to the antibody and nAChR. Moreover, modification of the Glu-21 carboxyl group of cobrotoxin further reduced the nAChR binding activity, while the antigenicity remained unchange. Thus, our results conclude that the Glu-21 residue and the common interaction of the terminal Leu-1 alpha-amino group and the Asp-58 carboxyl group are related to the nAChR-binding activity of cobrotoxin, and the free carboxyl groups in cobrotoxin are conformation-essential.

Chemical modification of cationic groups of a novel alpha-neurotoxin (Oh-4) from king cobra (Ophiophagus hannah) venom

The cationic groups of arginine and lysine residues in Oh-4, a novel alpha-neurotoxin from king cobra (Ophiophagus hannah) venom were subjected to modification with p-hydroxyphenylglyoxal (HPG) and trinitrobenzene sulfonate (TNBS), respectively. Monoderivatization of Arg-35, resulted in a drastic loss in neurotoxicity to 25% of the native toxin. The activity was decreased to a greater extent with the derivative extensively modified on Arg-35, -9, and -37. The Arg-35-modified derivative retained about a half of the antigenicity of the native toxin, and extensive modification on Arg-9 and Arg-37 caused a further decrease in the antigenicity of the toxin molecule. Selective trinitrophenylation (TNP-) of Lys-51 caused losses of neurotoxicity and antigenicity by 77 and 83%, respectively. These results indicate that Arg-35 and Lys-51 in Oh-4 have important roles in the neurotoxicity. In contrast to the Arg residues at 9, 35, and 37, Lys-51 plays a more critical role in the antigenicity.

Differential roles of two tandem E2F sites in repression of the human p107 promoter by retinoblastoma and p107 proteins

Although many lines of evidence indicate that the cellular protein p107 is closely related to the retinoblastoma protein, the exact function of the p107 gene and its regulation are presently not known. To investigate the molecular mechanism controlling expression of the human p107 gene, a 5' flanking sequence of this gene was isolated and shown to promote high-level expression of a luciferase reporter gene in cycling human 293 and Saos-2 cells. Sequencing and transcription mapping analyses showed that the human p107 promoter is TATA-less and contains a tandem, direct repeat of E2F-binding sites, with the 3' copy overlapping the major transcription initiation site. Deletion analysis of the p107 promoter showed that a promoter DNA fragment containing only the two E2F sites together with the leader sequence could direct relatively efficient expression in 293 cells. Site-directed mutagenesis of these E2F sites revealed that although both sites were important for p107 promoter activity, mutation on the proximal, initiation site copy of the E2F site showed a stronger effect. The human p107 promoter could be repressed by the retinoblastoma protein and its own gene product. Interestingly, the repression was found to be mediated through the 5' copy of the E2F site. These studies demonstrate for the first time differential roles of two tandem E2F sites in promoter regulation.

Alterations in local cerebral glucose utilization in rats after chronic amphetamine administration without subsequent challenge

The 2-deoxyglucose (2-DG) method was used to study regional metabolic changes in rats following chronic d-amphetamine treatment without subsequent challenges. Four groups of rats were pretreated (intraperitoneal administration) with d-amphetamine (0, 1, 5, or 10 mg/kg) once per day for 14 days. After a 7-day abstinence period without further challenge, the 2-DG method was used to measure the rates of local cerebral glucose utilization (LCGU). Significant metabolic changes among the four groups were found in five brain regions, including the nucleus accumbens and the lateral habenular nucleus. Another four groups of rats with the same pretreatment regimens, challenged with 5 mg/kg d-amphetamine, were used for behavioral testing. The results showed intense stereotyped behaviors in the 5 mg/kg and the 10 mg/kg groups. In the steady state, however, there were no significant glucose utilization changes in the nigrostriatal system, which is thought to be related to stereotyped behaviors. During steady state, metabolic changes were found in a limited number of brain regions. No difference in LCGU was found in the sensitization-related regions. Further challenges with stimulants may be necessary to investigate the metabolic responses after sensitization.

The murine erythrocyte protein-4.2-encoding gene: similarities and differences in structure and expression from its human counterpart

We have isolated a complete cDNA encoding for the mouse erythrocyte protein 4.2 (P4.2). The entire P4.2 cDNA consists of 3465 nt with an open reading frame (ORF) of 691 amino acids. Northern blot analysis of mouse reticulocyte or spleen RNA using the P4.2 cDNA as a probe, detected a 3.5-kb message. The size of the mouse P4.2 cDNA or message that we obtained, appears to be different from those reported recently. Despite the similarity to the human P4.2 cDNAs, the mouse cDNA has a longer 3' untranslated region. A genomic clone covering the first exon and flanking sequences of the mouse P4.2 gene was isolated. Sequencing results from the first exon-intron junction region and polymerase chain reaction (PCR) experiments revealed that the mouse reticulocyte P4.2 RNA does not exhibit alternative splicing in the region identified in the human P4.2 RNA.

Determination of soluble nAChR-binding activity of alpha-neurotoxins by an innovative precipitation with DEAE-Sephacel

A simple and convenient method for determining the binding activity of alpha-neurotoxins toward soluble nicotinic acetylcholine receptor (snAChR) by precipitation with DEAE-Sephacel was established. The determination was carried out by incubation of 125I-neurotoxin with snAChR, followed by precipitation with DEAE-Sephacel. The DEAE-Sephacel particles bind negatively charged snAChR with high affinity and simultaneously precipitate the 125I-neurotoxin bound to the receptors. After centrifugation, the free 125I-neurotoxin in the supernatant was counted, and the amounts of neurotoxins bound to snAChR could be determined. Two alpha-neurotoxins, cobrotoxin and alpha-bungarotoxin, were employed to verify the feasibility of this determination. The different binding characteristics of cobrotoxin and alpha-bungarotoxin to snAChR could be distinguished. This method required only small quantities of DEAE-Sephacel (7 mg), snAChR (0.54 micrograms), and 125I-neurotoxin (90 fmol) for each reaction, and minimized the handling of isotopic materials as compared with the conventional methods. This method is reliable, reproducible, and superior to current methods for the determination of the snAChR-binding activity for alpha-neurotoxins.

Adrenal cortical carcinoma with tumor thrombus invasion of inferior vena cava

A case of adrenal cortical carcinoma with inferior vena cava (IVC) involvement is presented. Ultrasonography, computed tomography, and venacavography all presumptively showed a large mass over the upper pole of the left kidney with tumor thrombus in the IVC. However, aortography demonstrated that this mass was receiving its blood supply from the left inferior phrenic artery, aorta, and left renal artery. Radical surgery, including resection of the tumor and its adjacent organs (kidney, distal pancreas, spleen) and the tumor thrombus in the IVC, with the aid of cardiopulmonary bypass, was performed. We emphasize that adrenal cortical carcinoma can have tumor thrombi invading the IVC, and in such cases we suggest radical surgical removal of the tumor and the thrombus.

A conserved region in the amino terminus of DNA polymerase delta is involved in proliferating cell nuclear antigen binding

Synthetic peptides to selected sequences in human DNA polymerase delta (pol delta) were used to identify the region involved in the interaction of pol delta to proliferating cell nuclear antigen. Peptides corresponding to sequences in five regions in the amino terminus of human pol delta and three in the carboxyl terminus, which are conserved with the yeast homologs of pol delta, were tested. These studies showed that the peptide corresponding to the N2 region (residues 129-149) selectively and specifically inhibited the PCNA stimulation of pol delta. This inhibition was relieved by titration with excess PCNA. The identification of the N-2 region as being involved in PCNA binding was supported by studies that demonstrated that the N2 peptide could bind PCNA. Deletion mutants of pol delta expressed in Sf9 cells provided evidence that the binding region for PCNA was located in the first 182 residues of the amino terminus. These studies provide reasonable evidence that residues within the region 129-149 of pol delta are involved in the binding site for PCNA.

Evidence showing a different repertoire of antibodies against unfolded cobrotoxin in anticobrotoxin and anti-reduced and S-carboxymethylated cobrotoxin antisera

Antibodies which specifically reacted with reduced and S-carboxy-methylated(RCM) cobrotoxin were purified from anticobrotoxin antisera and anti-RCM-cobrotoxin antisera, respectively. Results using a competitive immunoassay revealed that the antibodies from anti-RCM-cobrotoxin antisera had a greater affinity for RCM-cobrotoxin than for cobrotoxin. Whereas the reactivity of the antibodies from the anticobrotoxin antisera toward cobrotoxin and RCM-cobrotoxin had a reversed order of binding. In contrast to observations made with S. aureus V8 protease-digest hydrolysates, the antigenic structures of RCM-cobrotoxin recognized by antibodies from anti-RCM-cobrotoxin antisera were notably affected following hydrolysis of RCM-cobrotoxin with chymotrypsin. Moreover, the chymotryptic hydrolysates showed a comparable reactivity as RCM-cobrotoxin toward the antibodies purified from anticobrotoxin antibodies, but a decrease in antigenicity with the V8 protease hydrolysates. These results reveal that the repertoire of antibodies against the unfolded cobrotoxin are not the same in anticobrotoxin and anti-RCM-cobrotoxin antisera. Moreover, it suggests that the repertoire of antibodies from the different sources against the same antigen can be differentiated by measurement of their reactivities with the proteolytic hydrolysates of the antigen.

Analysis of a conformation-independent epitope and a conformational epitope in a protein: a study on cobrotoxin from Taiwan cobra venom

The antibodies against cobrotoxin were separated into two antibody preparations by successive affinity chromatographies on reduced and S-carboxymethylated (RCM)-cobrotoxin-Sepharose, and cobrotoxin-Sepharose columns. The antibodies (abbreviated as Abcf-i) that bound with the RCM-cobrotoxin-Sepharose were verified to specifically recognize the continuous epitopes of cobrotoxin, which were insensitive to conformational changes. Whilst the antibodies (abbreviated as Abcf-d) that did not bind with the RCM-cobrotoxin-Sepharose column recognized the conformational epitopes in cobrotoxin. The two antibody preparations were employed to screen the antigenic peptides derived from the proteolytic hydrolysate of cobrotoxin and RCM-cobrotoxin. Five antigenic peptides (AP-4, AP-5, AP-10, AP-11, and AP-12) were obtained from the acid protease A-digested hydrolysate of cobrotoxin, and two antigenic peptides (V8-2 and V8-4) were found in the hydrolysate of RCM-cobrotoxin after hydrolysis with Saccharomyces aureus V8 protease. The segments at positions 1-21 and 22-38 encompassed the peptide fractions, AP-4, AP-5, V8-2, and V8-4, that reacted with Abcf-i, indicating that the two segments bore the continuous epitopes of cobrotoxin. Alternatively, AP-10, AP-11, and AP-12 reacted with both Abcf-i and Abcf-d. The structures of the three peptides had a common segment at positions 43-62, suggesting that this region comprised the conformation-independent epitopes as well as conformational epitopes in cobrotoxin. These results reflected that the conformation-independent and conformational epitopes in a protein can be separately identified.

Metabolic and behavioral response in rats treated with amphetamine chronically with and without challenge

Chronic amphetamine (AMPH) treatment may cause behavioral sensitization in animals and can be used as an animal model of psychosis. The aim of the study was to check the behavioral and metabolic response in this animal model. In rats pretreated with normal saline (NS) or AMPH, with or without AMPH challenge, the [14C]deoxyglucose method was employed to check the metabolic changes in 42 regions. Behavioral testing was performed in rats with the same treatment. The results showed that after challenge with AMPH, glucose utilization was enhanced in most of the regions investigated. However, metabolic enhancement of the AMPH-pretreated group was lower in the caudate nucleus when compared with that of the NS-pretreated group though the stereotypy rating was higher in the former. Dissociation between the metabolic enhancement and behavioral response was noted. Furthermore, more significant differences between the two pretreated conditions of glucose utilization were found with challenge than without challenge. Further evaluation using procedures which include advanced techniques can be applied in further investigation.

The structural loop II of cobrotoxin is the main binding region for nAChR and epitope in the region is conformation-dependent

Modification of positively charged residues, Lys and Arg, in cobrotoxin revealed that Lys-27, Lys-47, Arg-28, Arg-30, Arg-33, and Arg-36 of cobrotoxin were essential for the lethality and binding activity to nicotinic acetylcholine receptor (nAChR). The antigenicity of cobrotoxin was drastically diminished when Lys-47, Arg-28, Arg-30, Arg-33, and Arg-36 were modified, while that of the Lys-27-modified derivative was not significantly changed. The CD spectra of cobrotoxin displayed similar patterns after modification of Lys-27, Lys-47, and Arg-28. These findings suggest that Lys-27, Lys-47, and Arg-28 residues may be related to the direct binding to nAChR, and that there is no involvement of Lys-27 in the antigenic determinants of cobrotoxin. Extending the modification to Arg-30, Arg-33, and Arg-36 caused progressive conformational changes of cobrotoxin and resulted in decreased binding activity to antibody and nAChR. This indicates that Arg-30, Arg-33, and Arg-36 may be of structural importance for maintaining the active conformation of cobrotoxin. These results, together with the facts that Tyr-25, Tyr-35, and Trp-29 of cobrotoxin are important in nAChR binding activity, but Trp-29 and Tyr-35 residues are not essential for the antigenicity, suggest that the structural loop II of cobrotoxin is the main binding region for nAChR and the epitope in that region is conformation-dependent.

Chemical modification of tryptophan residues in alpha-neurotoxins from Ophiophagus hannah (king cobra) venom

Two alpha-neurotoxins, Oh-4 and Oh-7, from the king cobra (Ophiophagus hannah) venom were subjected to Trp modification with 2-nitrophenylsulfenyl chloride (NPS-Cl). One major NPS derivative was isolated from the modified mixtures of Oh-4 and two from Oh-7 by HPLC. Amino acid analysis and sequence determination revealed that Trp-27 in Oh-4, and Trp-30 and Trp-26 and 30 in the two Oh-7 derivatives, were modified, respectively. Sulfenylation of Trp-27 in Oh-4 caused about 70% drop in lethal toxicity and nicotinic acetylcholine receptor-binding activity. Modification of Trp-30 in Oh-7 resulted in the decrease of lethal toxicity by 36% and binding activity by 61%. The activities were further lost when the conserved Trp-26 in Oh-7 was modified. Sulfenylation of the Trp residues did not significantly affect the secondary structure of the toxins as revealed by the CD spectra. These results indicate that the Trp residues in these two long alpha-neurotoxins may be involved in the receptor binding.

Blood flow of the urinary bladder: effects of outlet obstruction and correlation with bioenergetic metabolism

This study investigated the effects of outlet obstruction on blood flow and high energy phosphates content in the rabbit urinary bladder. Mild bladder outlet obstruction was induced by placing a silicon ring (diameter 7 mm) around the bladder neck of each male New Zealand White rabbit (n = 7). Before and immediately after inducing obstruction, and 2 weeks later, the bladders were emptied and regional blood flow measured using laser Doppler flowmetry (LASERFLO BPM2, Vasamedics Inc., St. Paul, Minnesota). Six different areas of each bladder were measured, and the average blood flow calculated for each rabbit. Then, the animals were sacrificed, the bladder excised, and the tissue content of high energy phosphates determined by high performance liquid chromatography (HPLC). Six normal male New Zealand White rabbits served as controls. The results can be summarized as follows: (1) Before surgery, bladder blood flow was similar in all animals (16.3 ml/min/100 g); positioning the silicon ring around the bladder neck did not affect blood perfusion, two weeks after the induction of outlet obstruction, bladder blood flow was significantly decreased (4.9 ml/min/100 g). (2) There was no significant difference between control and obstructed bladders in NAD, AMP, or ADP content. However, the obstructed bladders contained significantly less phosphocreatine (12.0 vs 21.9 nmol/mg protein) and ATP (4.0 vs. 6.1 nmol/mg protein) than control bladders. In summary, this study showed that urinary bladder blood flow was reduced by outlet obstruction, and the reduction in blood flow was associated with decreased tissue high energy phosphates content.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphological change in the urothelium after electrohydraulic versus pulsed dye laser lithotripsy

OBJECTIVE

To observe morphological changes in the urothelium after exposure to laser beam and electrohydraulic spark.

MATERIALS AND METHODS

The pulse dye laser lithotripter (MDL-2, Candela Corporation, Boston, USA) and the electrohydraulic lithotripter (AEH-2, Circon ACMI Corporation Stamford, USA) were used directly on the bladder mucosa in six pigs. Immediately after treatment, the bladder mucosa was prepared for light microscopic and scanning electron microscopic examination.

RESULTS

Both electrohydraulic spark and laser beam caused mucosal denudation, submucosal swelling and haemorrhage. There was a positive correlation between the degree of urothelial damage and the power and pulse numbers applied.

CONCLUSION

Direct contact of the urothelium in patients treated with laser beam or electrohydraulic spark should be avoided.

Hb E/Hb LeporeHollandia in a family from Bangladesh

We describe a family from Bangladesh in which three children are compound heterozygotes for Hb E (alpha 2 beta 2, beta 26Glu Lys) and Hb Lepore (delta-beta fusion gene). PCR amplification and direct nucleotide sequencing established that the fusion gene is Hb LeporeHollandia, with the cross-over localized to a 40 bp window between codon 22 and IVS-1 nt 16 of the delta- and beta-globin genes. This unusual combination of mutations is associated with a relatively mild clinical phenotype, with all three affected siblings having microcytic anemia of moderate severity without the need for transfusions.

Immunological neutralization of cobrotoxin by its homologous precipitin and non-precipitin antibodies

Anti-cobrotoxin antibodies can be separated into precipitin and non-precipitin antibodies. The precipitin antibody possesses the same binding affinity to cobrotoxin as non-precipitin antibody, but the neutralizing capability of the latter is superior to that of the former in blocking cobrotoxin binding to nicotinic acetylcholine receptor (nAChR). After preincubation with antibodies, cobrotoxin completely lost its binding activity to nAChR. The dissociation of cobrotoxin-nAChR complex by the antibodies was low, and 60% of the complex formation appeared to be irreversible. These results indicate that the neutralization of cobrotoxin by the antibody may predominantly involve unbound, receptor-free cobrotoxin. The relationships of neutralization capacity and binding affinity as well as bond strength between cobrotoxin and its antibodies are incongruous. Different local conformational changes of a unique Trp in cobrotoxin on binding with the precipitin and non-precipitin antibodies seem to lead to different accessibility for fluorescence quenchers. Characterization of the binding domains by immunoprecipitation with the antibodies correlated with the quenching results. Thus, the binding topography of cobrotoxin may play an important role over the binding affinity and bond strength in neutralization by cobrotoxin antibody.

The long-term stone recurrence rate and renal function change in unilateral nephrectomy urolithiasis patients

We evaluated the stone recurrence rate and long-term renal function in 50 patients with a solitary kidney 60 to 84 months (mean 70.6) after unilateral nephrectomy for urinary tract stone disease. Followup evaluation included a detailed history, physical examination, blood and urine biochemistry studies, urinalysis, urine culture, excretory urography, ultrasonography of the kidney and 131iodine-ortho-iodohippurate renography. The overall stone recurrence rate in unilateral nephrectomy urolithiasis patients was 30% (15 of 50). The mean interval until stone recurrence was 31.1 months (range 6 to 74) and the mean episodes of recurrence were 2.1 times per patient (range 1 to 5). Function of the remnant kidney in most patients was unchanged during followup. However, 2 of the 15 patients with recurrent stones had anuria during the acute attack of renal colic and, thus, required percutaneous nephrostomy urinary diversion, while 1 had proteinuria (3 gm. per day) and progressive renal failure 47 months after nephrectomy. The metabolic stone patients seemed to experience recurrence more easily than metabolic stone patients seemed to experience recurrence more easily than infection stone patients (37% versus 13%) but no statistically significant difference was noted (p = 0.198).

Functional involvement of Lys-6 in the enzymatic activity of phospholipase A2 from Bungarus multicinctus (Taiwan banded krait) snake venom

Phospholipase A2 (PLA2) from Bungarus multicinctus snake venom was subjected to Lys modification with 4-chloro-3,5-dinitrobenzoate and trinitrobenzene sulfonic acid, and one major carboxydinitrophenylated (CDNP) PLA2 and two trinitrophenylated (TNP) derivatives (TNP-1 and TNP-2) were separated by high-performance liquid chromatography. The results of amino acid analysis and sequence determination revealed that CDNP-PLA2 and TNP-1 contained one modified Lys residue at position 6, and both Lys-6 and Lys-62 were modified in TNP-2. It seemed that the Lys-6 was more accessible to modified reagents than other Lys residues in PLA2. Modification of Lys-6 caused a 94% drop in enzymatic activity as observed with CDNP-PLA2 and TNP-1. Alternatively, the enzyme modified on both Lys-6 and Lys-62 retained little PLA2 activity. Either carboxydinitrophenylation or trinitrophenylation did not significantly affect the secondary structure of the enzyme molecule as revealed by the CD spectra, and Ca2+ binding and antigenicity of Lys-6-modified PLA2 were unaffected. Conversion of nitro groups to amino groups resulted in a partial restoration of enzymatic activity of CDNP-PLA2 to 32% of that of PLA2. It reflected that the positively charged side chain of Lys-6 might play an exclusive role in PLA2 activity. The TNP derivatives could be regenerated with hydrazine hydrochloride. The biological activity of the regenerated PLA2 is almost the same as that of native PLA2. These results suggest that the intact Lys-6 is essential for the enzymatic activity of PLA2, and that incorporation of a bulky CDNP or TNP group on Lys-6 might give rise to the distortion of the interaction between substrate and the enzyme molecule, and the active conformation of PLA2.

Energy transfer from tryptophan residues of proteins to 8-anilinonaphthalene-1-sulfonate

The binding of the apolar fluorescent dye 8-anilinonaphthalene-1-sulfonate (ANS) to bovine serum albumin (BSA), phospholipase A2 (PLA2), ovalbumin, lysozyme, cobrotoxin and N-acetyltryptophanamide was used to assess the factors affecting the efficiency of energy transfer from Trp residues to the ANS molecule. We found that the efficiency of energy transfer from Trp residues to ANS was associated with the ability of proteins to enhance the ANS fluorescence. At the same molar concentration of protein, BSA enhanced ANS fluorescence most among these proteins; its Trp fluorescence was drastically quenched by the addition of ANS. Fluorescence enhancement of ANS in PLA2-ANS complex increased upon addition of Ca2+ or change of the buffer to acidic pH, resulting in a higher efficiency of energy transfer from Trp residues to ANS. There was limited ANS fluorescence enhancement with ovalbumin, lysozyme, cobrotoxin, and N-acetyltryptophanamide and a less efficient quenching in Trp fluorescence. The capabilities of proteins for binding with ANS correlated with the decrease in their Trp fluorescence being quenching by ANS. However, the microenvironment surrounding Trp residues of proteins did not affect the energy transfer. Based on these results, the factors that affected the energy transfer from Trp residues to ANS are discussed.

Improvement in the binding of cobrotoxin to microtiter plates by glutaraldehyde at neutral pH

The coating of the wells of microtiter plates with cobrotoxin in Tris (pH 9.8) or PBS (pH 7.2) buffer was assessed by enzyme-linked immunoassay (ELISA). It was found that the poor binding in neutral buffer was improved by adding glutaraldehyde (GA), and the bound amount reached the same extent as that measured with alkali buffer. The optimal concentration of GA was approx. 0.02%. A decrease in optical density was observed with GA concentration higher than 0.02%. This may result from the modification of cobrotoxin by GA, which induced a decrease in the antigenicity of the cobrotoxin as revealed by competitive immunoassay. This study implies that the coating of physiological samples with GA for ELISA may be carried out with physiological buffers without the need to change the buffer to one of alkaline pH.

Chemical modification of Lys-6 in Taiwan cobra phospholipase A2 with 4-chloro-3,5-dinitrobenzoate

Phospholipase A2 (PLA2) from Naja naja atra snake venom was modified with 4-chloro-3,5-dinitrobenzoate, and one major carboxydinitrophenylated (CDNP) PLA2 was separated by high performance liquid chromato-graphy. CDNP-PLA2 contained only one CDNP group on Lys-6 and showed a 93% drop in enzymatic activity. However, carboxydinitrophenylation did not significantly affect the secondary structure of the enzyme molecule as revealed by the CD spectra, and Ca2+ binding and antigenicity of CDNP-PLA2 were unaffected. Conversion of nitro groups to amino groups resulted in a partial restoration of enzymatic activity of CDNP-PLA2 to 35% of that of native enzyme. These results suggested that the positively charged side chain of Lys-6 played a role in the enzymatic mechanism of PLA2. However, the partial restoration in PLA2 activity reflects that a distortion of the active conformation arising from incorporation of a bulky CDNP group should occur.

The time for serum testosterone to reach castrate level after bilateral orchiectomy or oral estrogen in the management of metastatic prostatic cancer

OBJECTIVE

To understand the time for serum testosterone to reach castrate level after bilateral orchiectomy or oral estrogen in the management of metastatic prostatic cancer.

METHODS

A total of 20 consecutive patients with adenocarcinoma of the prostate with bony metastasis were enrolled in this study. Their mean age was 72.8 years old (range, 57 to 82 years). Pretreatment serum testosterone levels were obtained in all men. Thirteen men were treated with bilateral orchiectomy. Immediately after removal of testes, serial blood samplings for serum testosterone levels were drawn every fifteen minutes for the first two hours, then hourly for another sixteen hours. Seven men were treated with oral estrogen diethylstilbestrol (DES), 3 mg per day. Serum testosterone levels were checked on a weekly basis for two months, and then biweekly for another two months.

RESULTS

Castration time of bilateral orchiectomy ranges from three to twelve hours (mean, 8.6 hours). The biological half-life of serum testosterone was from thirty to sixty minutes (mean, 45 minutes). Castration time of oral estrogen (DES) was from twenty-one to sixty days (mean, 38.3 days).

CONCLUSIONS

Bilateral orchiectomy and oral estrogen were both effective ways of castration for patients with bony metastatic prostatic cancer. Bilateral orchiectomy provides a more rapid castration and is one hundred seven times faster than oral estrogen in reaching castrate level.

Biochemical regulation of the activity of gamma-glutamylcysteine synthetase from rat liver and kidney by glutathione

Rat liver and kidney gamma-glutamylcysteine synthetase (gamma GCS) had similar catalytic properties and consisted of heavy and light subunits, but the molecular structure of the two enzymes was not the same as evidenced by the results of SDS-PAGE and disc gel electrophoresis. Unlike kidney enzyme, most of liver gamma GCS was in a reduced enzyme form which did not have disulfide linkage between heavy and light subunits. Although the oxidized form of the two enzymes which subunits were linked with disulfide bond(s) could be dissociated to a similar extent by GSH, liver gamma GCS was inhibited by GSH to a much greater extent. These results suggest that the relative sensitivity of the gamma GCS enzymes to inhibition by GSH might be related to the inherent dissociability of heavy and light subunit of gamma GCS.

The essentiality of B chain in stabilizing the structure of the A chain in beta 1-bungarotoxin from Bungarus multicinctus venom

The dynamic of Trp residue in beta 1-bungarotoxin (beta 1-Bgt), the A chain of beta 1-Bgt and phospholipase A2 (PLA2) was assessed by fluorescence measurement. Acrylamide quenching studies showed that the exposure degree of the Trp in PLA2 is higher than the Trp in beta 1-Bgt. The Trp of beta 1-Bgt had a higher accessibility for iodide, reflecting that the basic nature of the B chain might exert an attractive electrostatic force for iodide and increase the susceptibility of Trp in the A chain to iodide. Removal of the B chain of beta 1-Bgt did not significantly affect the exposure degree of Trp in the A chain. Alternatively, the polarity of the environment around the Trp and the hydrophobic character of ANS and substrate binding sites in the separated A chain changed. Measurement of Trp fluorescence with increasing temperature showed that the stability of structure of beta 1-Bgt was higher than those of the separated A chain and PLA2. These results suggest that the B chain might interact with the A chain and stabilize the conformation of the A chain in beta 1-Bgt.

Prediction of lymphatic spreading in prostatic cancer by prostate-specific antigen and Gleason's score

A total of 58 patients have undergone bilateral pelvic lymphadenectomy as a staging procedure for clinically localized adenocarcinoma of the prostate. Of these, 19 patients (33%) had pelvic lymph node involvement. When a cutoff value of 50 ng/ml was used, the preoperative prostate-specific antigen (PSA) value had a positive predictive value of 57% for pelvic lymph node metastasis. Of the patients with PSA < 20 ng/ml, only 1 (4%) had evidence of lymph node metastasis. None of the patients with well-differentiated tumor (Gleason 2-4) had lymphatic spreading. In contrast, 82% of patients with poorly differentiated tumor (Gleason 8-10) had positive pelvic lymph nodes. Those patients with high PSA (> or = 20 ng/ml) and high Gleason's score (> or = 8) had the highest incidence of nodal extension (90%).

Decreased blood flow and defective energy metabolism in the varicocele-bearing testicles of rats

This study was designed to elucidate the hemodynamic and energetic changes of testicles in experimental varicocele. Partial ligation of the left renal vein was performed in 10 Sprague-Dawley rats to induce dilatation of the internal spermatic vein, and sham operation was performed in the other 10 age-matched Sprague-Dawley rats used as controls. Blood pressure and rectal temperature were maintained at a constant level. Testicular blood flow was detected by laser Doppler flowmeter on the day before surgery and 4 weeks after surgery, respectively. Concentrations of various adenine nucleotides were determined by high-performance liquid chromatography (HPLC). We found a significant decrease from 10.2 +/- 1.5 to 7.4 +/- 1.8 mlLD/min/100 g (p < 0.005) in testicular blood flow after inducing varicocele in the rats. The energy charge of adenine nucleotides of the varicocele-bearing rats was 0.62 +/- 0.07 which was significantly lower than the 0.73 +/- 0.02 of the control group (p < 0.005). These observations have, thus, led us to propose the hypothesis that impaired spermatogenesis may result from defective energy metabolism in the varicocele-bearing testicles of rats.

Long-term stone regrowth and recurrence rates after extracorporeal shock wave lithotripsy

We reviewed 1055 patients with symptomatic urinary calculi treated by extracorporeal shock wave lithotripsy (ESWL) monotherapy to determine the long-term stone regrowth and recurrence rates as correlated with the pre-treatment stone burden, site and multiplicity. Long-term follow-up (mean 75.8 months) was available in 94 patients, representing 106 renal units. The recurrence of stone was defined as reappearance of stone on follow-up plain abdominal radiographs. The regrowth of stone was defined as stone regrowing larger than one-third of the original residual size. A stone-free rate of 53% was achieved. The overall stone regrowth and recurrence rates were 26 and 15% respectively. It was concluded that the stone recurrence rate after ESWL was not influenced significantly by the stone size or the multiplicity, but that the regrowth rate was. Stone recurrence and regrowth rates after ESWL were both influenced by the stone location.

Role of the spermatic artery in spermatogenesis and sex hormone synthesis

This study was conducted to determine whether the spermatogenesis of testes and the serum sex hormone synthesis are influenced by the ligation of spermatic arteries. Sixteen adult male dogs were randomly divided into four groups. From our preliminary data the spermatogenic arrest and decrease of testicular volume were noted prominently in dogs after ligation of spermatic arteries. The serum testosterone level decreased and the serum luteinizing hormone level increased significantly in the same groups, while no significant changes were found in the dogs with preserved spermatic arteries. There were no significant differences in the epididymis and serum follicle-stimulating hormone among the four groups. This study attempted to establish the critical role of spermatic arteries in testicular function.

Identification of functional involvement of tryptophan residues in phospholipase A2 from Naja naja atra (Taiwan cobra) snake venom

Phospholipase A2 (PLA2) from Naja naja atra snake venom was subjected to Trp modification with 2-nitrophenylsulfenyl chloride (NPS-Cl), and six derivatives were separated by HPLC. The results of amino-acid analysis and sequence determination revealed that Trp-18, Trp-19 and Trp-61 were modified by NPS-Cl. The order of accessibilities of the three Trp residues for NPS-Cl was Trp-18 > Trp-19 > Trp-61. Sulfenylation of Trp-18 caused a 92% drop in enzymatic activity. Modification of Trp-19 and Trp-61 resulted in a decrease in enzymatic activity of PLA2 by 45.5% and 51%, respectively. The enzyme modified on both Trp-18 and Trp-19 or on both Trp-18 and Trp-61 retained little PLA2 activity. It is evident that Trp-18 plays a more crucial function in PLA2 than Trp-19 and Trp-61. Sulfenylation did not significantly affect the secondary structure of the enzyme molecule as revealed by the CD spectra, and Ca2+ binding and antigenicity of sulfenylated PLA2 was unaffected. These observations, together with the fact that Trp-18 is involved in the substrate binding of PLA2, suggest that incorporation of a bulky NPS group on Trp-18 might give rise to a direct distortion of the interaction between substrate and the enzyme molecule. Alternatively, modification of Trp-19 and Trp-61 might indirectly affect the interfacial binding of PLA2 with its substrate.

Deoxyribonucleic acid histogram of testes in primary transsexualism

The influence of oestrogen on spermatogenesis was evaluated by comparing its effect on the testes of primary male transsexuals and those who had undergone hormone therapy for prostatic carcinoma. Eight primary transsexuals were studied. They had been diagnosed on clinical and psychiatric evidence and had been on oestrogen therapy for several years since puberty. Histological sections of testicular tissue obtained at reassignment surgery from 8 phenotypic male transsexuals (aged 24-32 years) with an XY chromosome complement were studied by light microscopy. The formalin-embedded specimens were analysed by flow cytometry for deoxyribonucleic acid (DNA) histograms. Both the histology and DNA histograms revealed a pattern of maturation arrest in 12 of 16 testes in which the diploid cell compartment occupied most of the spermatogenetic element, followed by tetraploid and monoploid cells. Two testes showed impaired spermatogenesis and 2 were normal. The DNA histograms and pathology were also evaluated in 20 testes after 3 to 8 years of hormone therapy in patients with advanced prostatic carcinoma (aged 60-78 years). No maturation arrest was found in these patients. Sixteen of them had a pattern of fibrosis and atrophy and 4 had impaired spermatogenesis. It was concluded that oestrogen influenced spermatogenesis and affected the maturation of spermatogonia mostly during puberty.

Structural determinants of the intrinsic fluorescence emission in notexin and phospholipase A2 enzymes

Fluorescence measurements of the homologous proteins, notexin and PLA2 enzymes from Naja naja atra, Naja nigricollis, and Hemachatus haemachatus venoms, showed that the wave-length of maximum emission and the quantum yield of their intrinsic fluorescence emission spectra were different. To verify the factors which affected their fluorescence characteristics, the dynamics of tryptophan residues in those homologous proteins were studied by quenching with acrylamide, iodide, and cesium. The degrees of exposure of tryptophanyl groups in notexin and PLA2 enzymes assessed by acrylamide quenching were found to be the major factor that determined their fluorescence characteristics. However, the positively charged groups surrounding tryptophan residues of PLA2 enzymes from N. naja atra and N. nigricollis venoms might affect the quantum yield of their fluorophores. Tryptophan residues of notexin were in an environment with less fluctuation, which did not allow free diffusion of ionic quencher. This might render its tryptophan residues to fluoresce at a shorter wavelength. These results suggested that the structural determinants affecting the intrinsic fluorescence emission of homologous proteins can be easily assessed by quenching studies.

Efficacy of in vitro stone fragmentation by extracorporeal, electrohydraulic, and pulsed-dye laser lithotripsy

Fragmentation has become the standard therapy for urinary calculi in the modern era. Stone fragility as well as position and size are important for the determination of a treatment program. To compare the efficacy of stone fragmentation, seven kinds of human urinary calculi with known composition (calcium oxalate monohydrate and dihydrate, dibasic calcium phosphate, uric acid, struvite, calcium phosphate, and cystine) were treated by three fragmentation techniques commonly used, namely extracorporeal shock wave (SWL), electrohydraulic (EHL), and pulsed-dye laser lithotripsy. Uric acid, calcium oxalate dihydrate, and calcium phosphate stones could be destroyed easily by any of these methods. Struvite was soft but sticky and not easy to break into tiny particles. Both dibasic calcium phosphate and calcium oxalate monohydrate stones were resistant to the laser and EHL; SWL is the treatment of choice. For cystine stones, none of the treatments was satisfactory; SWL was the only way to break them into large pieces.