Impact of pulse pressure on the respiratory-related arterial pressure variability and its autonomic control in the rat

The autonomic control of respiratory-related arterial pressure variability (RAPV) remains uncharacterised. We set out to test the hypothesis that the autonomic nervous system may participate in RAPV via its effect on pulse pressure (PP). Experiments were performed on adult male Sprague-Dawley rats anaesthetised with ketamine and paralysed with pancuronium under positive-pressure ventilation. Respiratory variability in each parameter was quantified by auto-spectral analysis and the relationship between variabilities in two signals assessed by cross-spectral analysis. PP and systolic pressure (SP) exhibited similar powers of respiratory variability that were far more pronounced than for diastolic pressure (DP) or mean pressure (MP). The variability in PP preceded that in SP, MP or DP. The largest phase lag occurred between PP and DP and was equivalent to the time delay of one pulse interval. Coherence between respiratory variabilities in PP and MP was nearly perfect. Propranolol dose dependently suppressed respiratory variability in each pressure parameter and eventually disrupted the PP-MP relationship in respiratory variability. However, the influence of lung volume on MP persisted with a near-zero phase lag. Combined administration of phentolamine and atropine facilitated respiratory variability in PP and SP and failed to block the effect of propranolol. However, the combined administration moved the dose/response curve of propranolol and respiratory variability in each pressure parameter to the right. We conclude that, in addition to non-autonomic mechanisms, RAPV may be facilitated by cardiac sympathetic function via the effect on PP variability. The autonomic mechanism can still be evoked during combined alpha-adrenoceptor and muscarinic blockade, possibly via baroreflex mechanisms.

Suppression of proline-directed protein kinase F(A) expression inhibits the growth of human chronic myeloid leukaemia cells

Initial studies revealed that proline-directed protein kinase F(A) (PDPK F(A)) was overexpressed in various cancerous tissues relative to normal controls. However, the functional role of overexpressed PDPK F(A) in cancer remains to be established. In this report, we explore the potential role of PDPK F(A) in leukaemia cell growth by investigating the effects of partial inhibition of this kinase on the malignant phenotype of human chronic myeloid leukaemia cells (K562). Cloning of PDPK F(A) cDNA and its recombinant antisense expression vector and PDPK F(A)-specific antibody were successfully developed. Two stable antisense clones of K562 cells were subcloned which expressed 70% and 45% of PDPK F(A) respectively, compared with control-transfected clone in both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, these two antisense clones expressed no significant suppression of any other related PDPK family members, indicating the specificity of these two antisense clones. Moreover, these antisense clones proportionally and potentially exhibited cell growth retardation, poor clonogenic growth in soft agar and loss of serum independence. The results demonstrate that specific antisense suppression of PDPK F(A) is sufficient to interfere with the growth of K562 cells, indicating that PDPK F(A) is essential for human chronic myeloid leukaemia cell growth.

Opposition of rapid baroreceptor resetting by prostanoids in rabbits

Arterial baroreceptors reset rapidly within minutes during acute hypertension; baroreceptor pressure threshold (Pth) is increased and the pressure-baroreceptor activity relation is shifted to the right. The purpose of the present study was to determine if prostacyclin (PGI2) or other prostanoids, released during acute hypertension modulate the magnitude of baroreceptor resetting. Baroreceptor activity was recorded from the vascularly-isolated carotid sinus during distension of the sinus with slow pressure ramp in rabbits anesthetized with chloralose. Pressure-activity curves were generated after holding carotid sinus pressure for 10-15 min from 30 to 100 mmHg. In control, the elevation of holding pressure increased Pth from 44+/- to 65+/-5 mmHg (p < 0.05, n = 12). In the presence of PGI2 (20 microM), Pth averaged 43+/-4 and 45+/-3 mmHg (n = 12) after holding pressure at 30 and 100 mmHg, respectively. In the control group before exposing the carotid sinus to indomethacin, an elevation of holding pressure increased Pth from 49+/-2 to 71+/-3 mmHg (p < 0.05, n = 12). After inhibition of the endogenous formation of prostanoids with indomethacin (20 microM), Pth increased by a significantly greater extent from 61+/-2 to 90+/-3 mmHg (p < 0.05, n = 12) with the increase in holding pressure. The slope of the pressure-activity curve (baroreceptor gain) was not influenced by the change in holding pressure. It was increased significantly by PGI2, while decreased by indomethacin. Neither the change in holding pressure nor PGI2 affected the circumferential wall strain of carotid sinus over a wide range of pressure alteration. The results suggest that PGI2 or other prostanoids released during acute hypertension sensitizes baroreceptors and provides a negative feedback mechanism that opposes and limits the magnitude of rapid baroreceptor resetting.

Inadequate stocking of antidotes in Taiwan: is it a serious problem?

OBJECTIVE

Insufficient hospital stock of a variety of poisoning antidotes is a worldwide problem. In an attempt to establish an antidote storage and distribution system for the response of the various poisoning accidents, we conducted a nationwide survey to characterize the current availability of selected antidotes and their anticipated need in Taiwan.

MATERIALS AND METHODS

A questionnaire was mailed to 834 hospitals to gather information on the availability, anticipated need, and preferred purchase policy of 20 selected antidotes. A survey on the availability of cyanide antidote in 523 cyanide-handling facilities and their neighboring hospitals was also conducted.

RESULTS

Hospitals of different size and service levels had a statistically significant difference in response rates. Except for pyridoxine, the availability and anticipated need for antidotes also varied significantly among different hospital groups. We found that physostigmine, cyanide antidote kit, BAL, EDTA, methylene blue, Vipera Russell formosensis antivenin, and botulism antitoxin were not available in most (>90%) hospitals. Interestingly, these antidotes are also among the most needed antidotes. Most hospitals preferred a government-ordered purchase of antidotes. In the survey of cyanide-processing facilities, a response rate of 24.1% was obtained and only 9.3% of these 107 facilities that both replied to the questionnaire and continued handling cyanide products had stocked cyanide antidote. It is noteworthy that cyanide antidote was also frequently lacking in the neighboring hospitals.

CONCLUSIONS

The appropriate storage of antidotes in hospitals or workplaces in rural areas is instrumental in the timely treatment of certain poisonings, while nationwide unavailability is the critical problem. Raising awareness of the importance of antidotes by education, regular review of antidote storage, distribution plans, and appropriate legislation might provide solutions.

Current seroprevalence of hepatitis A virus infection among kindergarten children and teachers in Taiwan

Taiwan was a hyperendemic area for hepatitis A virus (HAV) infection before the late 1980s. The seroprevalence of HAV infection was higher than 90% with most HAV infection occurring during childhood. This study was to estimate the seroprevalence of HAV infection among preschool children in central Taiwan. A community-based survey was carried out in 54 kindergartens in 10 urban areas, 10 rural areas and 2 aboriginal areas randomly selected through stratified sampling. Serum samples of 2,549 healthy preschool children and 104 teachers in study kindergartens were screened for the HAV antibodies (anti-HAV) by means of a commercially available microparticle enzyme immunoassay (AxSYM HAVAB). Among aboriginal kindergarten children, more than 96% of them were anti-HAV seropositive due to a mass HAV vaccination program. In urban and rural areas, kindergarten children had a very low prevalence of anti-HAV (0.4%) in contrast to a high seroprevalence in their teachers (78%). There was no gender difference in seroprevalence of anti-HAV, while the anti-HAV seroprevalence was significantly higher in urban areas than in rural areas. Crowdedness of living in urban areas might facilitate the person-to-person transmission of infectious agents.

Antisense suppression of proline-directed protein kinase FA enhances chemosensitivity in human prostate cancer cells

Initial clinic studies revealed that proline-directed protein kinase FA (PDPK FA) is overexpressed manyfold in various human cancerous tissues relative to the normal control. However, the role of overexpressed PDPK FA in cancers remains unknown and needs to be established. To determine whether PDPK FA is associated with drug sensitivity, we investigated the effects of partial inhibition of this kinase on the human prostate carcinoma cell line (PC-3). PDPK FA antisense expression vector and its specific antibody were successfully developed. Two stable transfected antisense clones (PA7 and PA3) of human prostate carcinoma cell were subcloned, and they expressed approximately 75% and approximately 35% of the total PDPK FA existing in the control-transfected clone as determined by both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, the PDPK FA antisense clones expressed no significant suppression of any other related proline-directed protein kinase member expression, demonstrating the specificity of these two antisense clones. When compared with parental or control-transfected cells, the low-PDPK FA-expressing antisense clones displayed an enhanced sensitivity to carboplatin, 5-fluorouracil, paclitaxel, and hydroxyurea. Estimation of the IC50 index further revealed that the antisense clones displayed up to > 100-fold drug sensitivity, and there was a correlation between suppressed levels of PDPK FA and drug sensitivity. Taken together, the results demonstrate that specific antisense suppression of overexpressed PDPK FA in human prostate cancer cells is sufficient to enhance various drug sensitivity, indicating that PDPK FA is an important regulator in controlling multiple drug resistance of human prostate cancer cells.

Rapid separation of lysozyme from chicken egg white by reductants and thermal treatment

Reductants (0.1-2.0% ascorbic acid, cysteine, or cystine and 0.04-1. 0% beta-mercaptoethanol) were added to 5-fold diluted, salted duck egg whites (commercially and laboratory prepared) and fresh egg whites (chicken and duck), and subsequently the mixtures were heated at 70 degrees C for 1-10 min. The maximal recovery and purification fold of lysozyme obtained from fresh chicken egg whites added with 1. 0% ascorbic acid were 78% and 2.4, respectively. Storage tests showed that the obtained lyophilized lysozyme powder after dialysis was stable when refrigerated at 4 degrees C for 3 months.

Altered frequency characteristic of central vasomotor control in SHR

Previous work from our laboratory has demonstrated that the very low-frequency (VLF: 0-0.25 Hz) and low-frequency (LF: 0.25-0.8 Hz) power of arterial pressure variability (APV) are related to vasomotor reactivity in response to control signals from the rostral ventrolateral medulla (RVLM) via the sympathetic system in the rat. The present study evaluated the differences in the dynamic property of central vasomotor control between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Experiments were carried out in 10- to 12-wk-old rats that were anesthetized with continuous infusion of pentobarbital sodium, paralyzed with pancuronium, and maintained on mechanical ventilation. We found that SHR exhibited significantly higher arterial pressure (AP), heart rate (HR), and VLF, LF, and high-frequency (0.8-2.4 Hz) power of APV than WKY under resting state. Broad-band electrical stimulation of the RVLM elicited parallel APV in the VLF and LF ranges in both rat strains. The evoked APV and transfer magnitude of the APV to stimulus spike rate variability (RVLM-AP magnitude) were significantly higher in SHR, especially in the LF range. The response frequency of central vasomotor control, represented by the high-cut frequency of RVLM-AP magnitude, was also extended in SHR. The disparity in RVLM-AP transfer magnitude between SHR and WKY became virtually absent after combined alpha- and beta-adrenoceptor blockade by phentolamine and propranolol. These results suggest that the dynamic control of RVLM on AP reactivity is enhanced in SHR, in which the adrenergic system may play a major role.

Hemodialysis as adjunctive therapy for severe acetaminophen poisoning: a case report

Acetaminophen overdose is a common intoxication in daily practice the standard treatment is N-acetylcysteine (NAC) antidotal therapy for possible poisoning. However, dialysis procedures can remove the drug from the body effectively. We describe a case of acetaminophen overdose that was treated with both hemodialysis (HD) and NAC due to severe intoxication and slow drug clearance. A 37-year-old woman attempted suicide by ingestion of 100 tablets (500 mg each) of acetaminophen, and presented with vomiting, hematemesis and abdominal pain. The patient had elevated liver enzymes, coagulation defects, thrombocytopenia a high serum acetaminophen level (201 mg/l at 12 hours post-ingestion) with a prolonged half-life. Oral NAC was given; however, it was ineffective due to severe vomiting and hematemesis. HD as adjunctive therapy was initiated at 19 hours post-ingestion. HD reduced the serum acetaminophen level from 102.77 to 35.77 mg/l. Severe hepatic injury, bacteremia and pancytopenia were noted in the following days. The patient later recovered after treatment with NAC, HD and intensive supportive care. HD removed 66% of the total acetaminophen body burden during a single four-hour session, increased the clearance by 2.75-fold and shortened the half-life from 7.2 hours to 2.6 hours during HD. Through NAC therapy is the standard regimen for acetaminophen poisoning, in the severely poisoned patient who cannot tolerate NAC therapy, HD may be used as adjunctive therapy to enhance the elimination of acetaminophen.

Cortical evoked responses from the perineal nerve

PURPOSE

We characterize and determine normal reference latencies for the cortical evoked response from the perineal nerve.

MATERIALS AND METHODS

A total of 15 healthy, potent men with a mean age of 31.3 +/- 6.8 years underwent genital electrophysiological testing. Square wave stimuli were applied to the perineal nerve at the ventral base of the penis and the perineal floor. Cortical evoked responses were recorded, and onset latencies were measured at baseline and after anesthetization of the dorsal nerve of the penis.

RESULTS

In all 15 subjects a cortical evoked response was elicited after stimulation of the perineal nerve at the ventral base of the penis with a mean latency measured from the first positive deflection (P1) of 48.4 +/- 7.8 milliseconds. Penile block of the dorsal nerve of the penis did not change or abolish the cortical evoked response. A similar cortical evoked response was obtained, although less consistently, after stimulation of the perineal nerve through its course in the perineal floor.

CONCLUSIONS

A cortical evoked response from the perineal nerve can be elicited reliably at the ventral penis. This neural pathway is independent of the dorsal nerve of the penis. The study of perineal somatic innervation may prove important in understanding the physiology of ejaculatory and erectile dysfunction.

Effect of aging on gender differences in neural control of heart rate

To clarify the influence of gender on sympathetic and parasympathetic control of heart rate in middle-aged subjects and on the subsequent aging process, heart rate variability (HRV) was studied in normal populations of women (n = 598) and men (n = 472) ranging in age from 40 to 79 yr. These groups were divided into eight age strata at 5-yr intervals and were clinically diagnosed as having no hypertension, hypotension, diabetic neuropathy, or cardiac arrhythmia. Frequency-domain analysis of short-term, stationary R-R intervals was performed, which reveals very-low-frequency power (VLF; 0.003-0.04 Hz), low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), the ratio of LF to HF (LF/HF), and LF and HF power in normalized units (LF% and HF%, respectively). The distribution of variance, VLF, LF, HF, and LF/HF exhibited acute skewness, which was adjusted by natural logarithmic transformation. Women had higher HF in the age strata from 40 to 49 yr, whereas men had higher LF% and LF/HF between 40 and 59 yr. No disparity in HRV measurements was found between the sexes in age strata >/=60 yr. Although absolute measurements of HRV (variance, VLF, LF, and HF) decreased linearly with age, no significant change in relative measurements (LF/HF, LF%, and HF%), especially in men, was detected until age 60 yr. We conclude that middle-aged women and men have a more dominant parasympathetic and sympathetic regulation of heart rate, respectively. The gender-related difference in parasympathetic regulation diminishes after age 50 yr, whereas a significant time delay for the disappearance of sympathetic dominance occurs in men.

Expression and mutagenesis studies of cobrotoxin from Taiwan cobra

The cDNA encoding cobrotoxin was constructed from the cellular RNA isolated from the venom glands of Naja naja atra (Taiwan cobra). The cDNA was subcloned into the expression vector pET20b(+) and transformed into BL21(DE3) Escherichia coli strain. Expressed cobrotoxin was isolated from inclusion bodies of E. coli and subjected to refolding into its folded structure. The refolded cobrotoxin was purified by high-performance liquid chromatography and exhibited a neurotoxicity in inhibiting acetylcholine-induced muscle contractions. Recombinant cobrotoxin showed a tendency to isomerize its disulfide bonds as that observed with native cobrotoxin. An appreciable decrease in the rate of isomerization reaction was observed when Glu-38 was replaced with Gln-38 or Lys-47 was replaced with Glu-47 or Gln-47. These results reflect that the element in controlling the disulfide isomerization of cobrotoxin is closely associated with the charged side chains in the cobrotoxin molecule.

Sequence requirements for incorporation of human immunodeficiency virus gag-beta-galactosidase fusion proteins into virus-like particles

The incorporation of human immunodeficiency virus type 1 (HIV-1) Gag-beta-galactosidase (Gag-beta-gal; GBG) fusion proteins into HIV virus-like particles in the presence of HIV Gag proteins was studied. HIV Gag-beta-gal fusion constructs were cotransfected individually into COS7 cells with or without an HIV Gag protein expression plasmid. Release of HIV GBG fusion proteins from the cells were measured by assay of the medium versus intracellular beta-gal activities. Analysis indicates that fusion proteins (constructs HIVGBG, GBG 1919 and 1877) retaining the C-terminal portion of the CA and the adjacent NC domains were efficiently assembled into virus-like particles. Fusion proteins with deleted sequences covering the N-terminal portions of the gag sequences (GBG 831, 1147, 1419, 1447, 1511, 1552, 1600, 1630, 1684, 1715, and 1752) were impaired in entry into virus-like particles. The presence of CA major homology region (MHR) in the fusion proteins had no significant effects on inducing fusion protein incorporation when the C-terminal CA sequences in the fusion proteins were truncated (GBG 1841 and 1801). Subcellular fractionation studies indicated that most fusion proteins including the nonmyristylated one were enriched in the crude membrane fraction. Exceptions to this rule were fusion proteins with intact MHR but truncated C-terminal CA sequences, which possessed low levels of membrane association. However, assembly of fusion proteins into HIV Gag particles did not correlate with their subcellular fractionation or immunofluorescence localization patterns. Overall, the studies suggest that the very C-terminal CA and adjacent NC sequences are the primary determinants for incorporation of HIV Gag-beta-gal fusion proteins into virus particles.

Laparoscopic resection of an omental cyst with pedicle torsion

Omental cysts are the least-common variety of all types of intra-abdominal cystic lesions. In the past, transabdominal laparotomy with excision of the cyst was the treatment of choice. With the advent of laparoscopic surgery, it has become possible to resect the cyst without the need for a large incision in the abdomen. We report a case of a 15-year-old girl who underwent diagnostic laparoscopy for recurring abdominal pain of 2 years' duration. The procedure revealed a huge cyst lying above the omentum with its pedicle rising from the greater curvature of the stomach. The pedicle was noted to have twisted eight times in a clockwise direction. The cyst was resected by laparoscopic means using three trocars. The postoperative course was uneventful. As presented in this case, we believe that a laparoscopic approach is an attractive alternative for the management of omental cystic lesions.

Evaluation of pre- and postdilutional on-line hemodiafiltration adequacy by partial dialysate quantification and on-line urea monitor

On-line highflux hemodiafiltration (HDF) is a clinically interesting and effective mode of renal replacement therapy, which offers the possibility to obtain an increased removal of both small and large solutes. The fundamental role of urea kinetic monitoring to assess dialysis adequacy in conventional hemodialysis has been widely studied. Both direct measurement of the urea removed by the modified direct dialysate quantitation (mDDQ) based on partial dialysate collection (PDC) and dialysate-based urea kinetic modeling (DUKM) using urea monitor have been advocated. The validity of this assessment tool in the patients with on-line HDF remained unclear. The aims of this investigation were (1) to compare the delivered Kt/V, urea mass removal (UMR), solute removal index (SRI) and normalized protein catabolic rate (nPCR) between pre- and postdilutional high-flux HDF; (2) to verify and compare the efficiency of pre- and postdilutional HDF using DUKM with on-line dialysate urea sensor, and mDDQ with partial dialysate collection. During both mode of HDF, the paired analysis urea removed and Kt/V showed no significant difference. Using mDDQ, mean values for predilutional mode were as follows: Kt/V 1.53 +/- 0.01 UMR, 16.8 +/- 0.3 g/session; urea clearance 178 +/- 18 ml/min; SRI 75.5 +/- 7.7%; urea distribution volume (V) 28.3 +/- 1.2 liters; nPCR 1.34 +/- 0.18 g/kg/day; on the other hand, mean values for postdilutional mode were Kt/V 1.58 +/- 0.01; UMR 17.10 +/- 0.28 g/session; urea clearance 184 +/- 21 ml/min; SRI 77.2 +/- 3.5%; urea distribution volume, 27.8 +/- 1.5 liters; nPCR 1.34 +/- 0.19 g/kg/day. The mean value of urea generation rate was 5.82 +/- 1.12 mg/min during HDF. Our results showed that dialysis adequacy was achieved with both high-volume predilutional HDF and postdilutional HDF. These two modes of HDF provided similar and adequate small solute clearance. In addition, we found that on-line analysis of urea kinetics is a reliable tool for quantifying and assuring delivery of adequate dialysis.

Pancreatic tuberculosis with obstructive jaundice--a case report

Isolated pancreatic tuberculosis (TB) is very rare and its treatment somewhat controversial. We report a case of pancreatic TB diagnosed as pancreatic carcinoma. An 82-yr-old man presented with right upper abdominal pain and obstructive jaundice, without fever or weight loss. Ultrasonography, computed tomography, and endoscopic retrograde cholangiopancreatography showed a mass lesion in the pancreatic head, which caused stricturing of the distal common bile duct and pancreatic duct in the head of the gland. As malignancy was suspected, he underwent a Whipple procedure (pancreaticoduodenectomy). Histological examination of the resection specimen disclosed typical features of tuberculosis in the pancreatic head, lymph nodes, and at the ampulla of Vater. The rest of the abdominal cavity was unremarkable. After receiving antimicrobial therapy for tuberculosis for 6 months, he remains well, without jaundice or a recurrent mass visible by ultrasound.

Diverse manifestations of oral methylene chloride poisoning: report of 6 cases

OBJECTIVE

Methylene chloride is a solvent used in domestic and industrial preparations, such as paint removers and degreasing agents. Although it is considered of low toxicity, acute toxic manifestations have been reported following inhalation of methylene chloride, mainly from working in an enclosed environment. Oral ingestion of methylene chloride, however, remains rare and its consequences are less clearly understood.

CASE REPORTS

The various clinical manifestations of 6 patients with oral ingestion of methylene chloride are reported. Central nervous system depression, tachypnea, and corrosive gastrointestinal injury were the most common presentations following ingestion. An elevated carboxyhemoglobin level was documented in only 2 patients (35% and 8.4% carboxyhemoglobin, respectively). Due to a frequent misleading history of "chloroform" ingestion and unawareness of probable carboxyhemoglobin production in these patients, carboxyhemoglobin was not routinely measured. Renal failure, hepatic failure, and acute pancreatitis occurred in the 2 most severe cases of methylene chloride ingestion.

CONCLUSIONS

Ingestion of methylene chloride can result in diverse manifestations, including a high carboxyhemoglobin level. Corrosive gastrointestinal injury is common in oral poisoning and needs further therapeutic consideration. A high index of suspicion and appropriate laboratory studies are needed in those patients who allegedly ingest "chloroform" but do not present the incriminating solvent to their treating physicians. The presence of an elevated carboxyhemoglobin level suggests the diagnosis of methylene chloride poisoning. Symptomatic and supportive measures remain the mainstay in the treatment of patients with oral methylene chloride poisoning.

Laparoscopic appendectomy for ruptured appendicitis

We conducted a retrospective analysis to assess the feasibility of laparoscopic appendectomy in cases of ruptured appendicitis. Between August 1993 and April 1998, a total of 328 laparoscopic appendectomies were performed in Min-Shen General Hospital. There were 34 cases of pathology-proven ruptured appendicitis. Patients were divided into three groups according to the operative findings: group 1 (10 cases) consisted of patients with a perforated appendix with local peritonitis, group 2 (15 cases) consisted of patients with perforated appendix with diffused peritonitis, and group 3 (9 cases) consisted of patients with abscess formation around the perforated appendix. Three cases in group 3 were converted to laparotomy and were excluded from this study. Mean age (+/- SD) was 30 +/- 15 years in group 1, 39 +/- 23 years in group 2, and 37 +/- 13 years in group 3. Duration of symptoms was longer in group 3 (4.2 +/-1.2 days) than in group 1 (1.8 +/- 1.3 days) and group 2 (2.3 +/- 1.2 days). There was no difference in operation time among groups 1 (52 +/- 10 min), 2 (64 +/- 13 min), and 3 (67 +/- 16 min). The time of flatus passage after operation was similar in the three groups (group 1, 17 +/- 11 hours; group 2, 21 +/- 12 hours; group 3, 24 +/- 8 hours). Hospital stay was significantly shorter in group 1 (3.0 +/- 1.1 days) than in group 2 (5.1 +/- 2.2 days) and group 3 (4.2 +/- 1.2 days). There were no complications and no readmissions. Our results indicate that the laparoscopic approach is feasible for ruptured appendicitis with local or diffuse peritonitis and in selected cases with abscess formation. However, prospective randomized controlled trials are needed to determine which procedure is to be recommended.

Reconstruction of fiber grating refractive-index profiles from complex bragg reflection spectra

Reconstruction of the refractive-index profiles of fiber gratings from their complex Bragg reflection spectra is experimentally demonstrated. The amplitude and phase of the complex reflection spectrum were measured with a balanced Michelson interferometer. By integrating the coupled-mode equations, we built the relationship between the complex coupling coefficient and the complex reflection spectrum as an iterative algorithm for reconstructing the index profile. This method is expected to be useful for reconstructing the index profiles of fiber gratings with any apodization, chirp, or dc structures. An apodized chirped grating and a uniform grating with a depression of index modulation were used to demonstrate the technique.

Agricultural avermectins: an uncommon but potentially fatal cause of pesticide poisoning

STUDY OBJECTIVE

Avermectins have been used in the control of parasites and insects; however, human data concerning poisoning are lacking. This study investigated the clinical spectrum of avermectin poisoning.

METHODS

A retrospective study was conducted to evaluate patients with avermectin poisoning reported to a poison center from September 1993 through December 1997.

RESULTS

Eighteen patients with abamectin (Agri-Mek; 2% wt/wt abamectin) exposure and 1 with ivermectin (Ivomec; 1% wt/vol ivermectin) ingestion were identified. There were 14 male and 5 female patients, ranging in age from 15 to 83 years. Most patients were exposed as a result of attempted suicide (14). Oral ingestion (15) was the most common route of exposure. Four patients were asymptomatic, and 8 had minor symptoms after a mean ingestion of 23 mg/kg abamectin (4.2 to 67 mg/kg), or after dermal and inhalation contact. Seven patients manifested severe symptoms, such as coma (7), aspiration with respiratory failure (4), and hypotension (3), after a mean ingestion of 100.7 mg/kg avermectin (15.4 mg/kg for ivermectin and 114.9 mg/kg for abamectin). All 7 patients received intensive supportive care; 1 patient died 18 days later as a result of multiple organ failure.

CONCLUSION

Ingestion of a large dose of avermectin may be associated with life-threatening coma, hypotension, and subsequent aspiration.

Preparation and characterization of beta 1-bungarotoxin bispecific monoclonal antibody

A hybrid hybridoma (tetradoma) that produces bispecific monoclonal antibodies (mAbs)2, which recognize two different epitopes on the A chain of beta 1-bungarotoxin (beta 1-bgt) at peptide sequences 46-51 and 100-106, has been obtained by fusing two hybridoma cell lines. The bispecific mAb were observed to inhibit 98% of the enzymatic activity of beta 1-bgt and neutralize its lethal toxicity completely. The avidity between the bispecific mAb and beta 1-bgt was noted to be 4.5 x 10(10) (liter/nmol), which is about 45-150 folds higher than the avidity of its two parental mAbs. All the soluble complexes, obtained from bispecific mAb and beta 1-bgt with different molar ratios, emerged in the void volume of size exclusion chromatography column, indicating multiple complexes of beta 1-bgt and bispecific mAb were formed. Based on these results, it indicated that the binding of bispecific mAb with its two epitopes on beta 1-bgt, which facilitates the immuno-complex formation and enhances the avidity, also highly neutralizes the biological activity of beta 1-bgt.

Small bowel perforation caused by a sharp bone: laparoscopic diagnosis and treatment

Small bowel perforation caused by sharp or pointed foreign bodies rarely is diagnosed preoperatively because clinical symptoms usually are nonspecific and can mimic other surgical conditions such as appendicitis and cecal diverticulitis. We report the case of a 57-year-old man who underwent diagnostic laparoscopy for abdominal pain of unknown etiology. Swelling and erythema were noted in a segment of small bowel in the right lower abdomen. A tiny sharp-pointed object was found penetrating the inflamed portion of the bowel. This foreign body was removed and the perforation immediately repaired under laparoscopic guidance. The postoperative course was uneventful. We believe that in cases of lower abdominal pain with peritoneal irritation, laparoscopy can provide not only a wide field of examination to localize intraabdominal pathology, but in some instances it can aid in case management.

Characteristics and risk factors of acetaminophen-induced hepatitis in Taiwan

BACKGROUND

Overdose of acetaminophen may cause hepatic injury and fatal fulminant hepatic failure. Acetaminophen is the most common form of drug-induced hepatic injury in Western countries. However, there is no formal report of this important issue in Taiwan. To assess the clinical characteristics and risk factors of acetaminophen-induced hepatitis in Taiwan, we conducted this study.

METHODS

A total of 71 patients who were intoxicated or overdosed with acetaminophen at Veterans General Hospital-Taipei between February, 1991 and June, 1997 were enrolled in this study. Acetaminophen-induced hepatitis was defined according to the Paris international consensus criteria.

RESULTS

Suicide attempt was the major cause (67/71) of acetaminophen overdose. Sixty-two of the patients were female. The mean patient age was 24.5 +/- 9.7 years (+/- standard deviation, SD). Nineteen of 71 patients had acetaminophen-induced hepatitis. The peak serum alanine aminotransferase, aspartate aminotransferase and total bilirubin concentrations were 4,181.0 +/- 931.4 IU/l (mean +/- SD), 4,148.0 +/- 1,147.5 IU/l and 2.6 +/- 0.4 mg/dl, respectively. The hepatitis group had higher ingested acetaminophen doses and serum peak acetaminophen levels than did those of the nonhepatitis group (24.9 g vs 12.9 g, p = 0.004; 132.0 mg/l vs 61.7 mg/l, p = 0.013). A higher percentage of alcohol consumption was also noted in the hepatitis group than in the nonhepatitis group (32% vs 12%, p = 0.05). After logistic regression for multivariate analysis, alcohol consumption was the most important risk factor for acetaminophen-induced hepatitis (odds ratio = 8.14, p = 0.018), followed by ingested acetaminophen dose (odds ratio = 1.21, p = 0.001). Most patients received acetylcysteine treatment in time. Two of the 19 patients with hepatitis died.

CONCLUSIONS

The majority of acetaminophen-induced hepatitis in Taiwan occurs in young females who attempt suicide. Alcohol consumption and the dose of acetaminophen ingested were the significant risk factors for acetaminophen-induced hepatitis. Alcohol should not be concomitantly used with acetaminophen. Early diagnosis and administration of the antidote are crucial to decrease mortality.

Cobrotoxin: structure and function

Cobrotoxin is the main neurotoxic protein isolated from the venom of Taiwan cobra Naja naja atra. It is a small, basic protein consisting of a single polypeptide chain of 62 amino acids, cross-linked by four disulfide bonds. The disulfide bonds and Tyr-25 which is buried in the molecule form a central core to maintain and stabilize the active conformation of the toxin. Selective and stepwise chemical modifications of cobrotoxin indicate that at least two cationic groups, an epsilon-amino group of Lys-47 and a guanidino group of Arg-33, both of which are common to all known postsynaptic neurotoxins, held at a certain critical distance in the molecule, are functionally important for its neuromuscular blocking activity. The cDNA encoding cobrotoxin was constructed from the cellular RNA isolated from the venom glands of Naja naja atra by reverse transcription polymerase chain reaction. Sequencing several clones containing about 0.5 Kb DNA inserts contained a complete and full-length reading frame of 249 base pairs covering a precursor of cobrotoxin gene with a deduced mature protein sequence of 62 amino acids which are identical to the amino acid sequence of cobrotoxin and a 21 amino acid segment of signal peptide. Expression of cobrotoxin in E. coli vector generated a polypeptide which can cross-react with the antisera against the native cobrotoxin.

Immunochemical study on beta1-bungarotoxin using polyclonal and monoclonal antibodies

The number of antigenic determinants of beta1-bungarotoxin (beta1-Bgt), A chain and B chain were determined to be seven, five and two, respectively, by quantitative precipitin reactions and analysis of the soluble complex formed from beta1-Bgt and Fab fragments of the antibody. The gel filtration patterns on a size exclusion column revealed that the soluble complexes formed from non-precipitating antibody and beta1-Bgt at a different molar ratio all emerged in the void volume, indicating that the molecular weight of the soluble complex is around 6000 kDa or more. The gel filtration pattern from Fab fragments of non-precipitating antibody also revealed that only 1 or 2 molecules of Fab fragments are bound to beta1-Bgt, A chain and B chain instead of seven, five and two molecules as in the case of precipitating antibody. Besides, twenty-three stable monoclonal antibodies (mAbs) were prepared against beta1-Bgt by the hybridoma technique. Most of these mAbs cross-reacted with isotoxins of the beta-Bgt family, as determined by an enzyme-linked immunosorbent assay, but none of them reacted with notexin, notechis II-5 and three PLA2 homologues, PLA2, DE-I and CMS-9.