Evidence against a role for endotoxin in the hyperdynamic circulation of rats with prehepatic portal hypertension

BACKGROUND/AIMS

Excessive formation of nitric oxide may mediate the generalized vasorelaxation and hyporesponsiveness to vasoconstrictors observed in portal hypertensive states. Endotoxin, released from the bowel and detoxified by the liver, could stimulate inducible nitric oxide synthase directly or indirectly via the cytokine cascade. This study investigated the effect of chronic intraperitoneal injection of polymyxin B, a neutralizing antagonist of endotoxin, on the hemodynamics of partially portal vein-ligated (PVL) rats.

METHODS

Concomitantly with endotoxin (600 EU) and dactinomycin (80 microg), polymyxin B (0.1 mg) or normal saline (N/S) was administered via an intraperitoneal route to male Sprague-Dawley rats. Twenty-four hours later, mean arterial pressure was determined. In PVL rats polymyxin B (0.1 mg in 5 cc N/S) or N/S was given intraperitoneally twice daily from 2 days prior to operation until 5 days (short-term) or 14 days (long-term) after the operation. Long-term polymyxin B- or N/S-treated sham-operated rats were included as controls. Hemodynamic studies with a thermodilution technique were performed at the end of treatment. Blood samples were collected from another series of PVL rats with long-term treatment to determine plasma levels of endotoxin and tumor necrosis factor-alpha. Plasma levels of endotoxin and tumor necrosis factor-alpha were measured by Limulus assay and the ELISA method, respectively.

RESULTS

With the dosage of 0.1 mg polymyxin B, hypotension in rats subjected to endotoxin and dactinomycin administration could be corrected (polymyxin B vs. placebo: 130.0+/-7.7 vs. 108.8+/-6.7 mm Hg, p<0.05). However, long-term or short-term treatment with the same dosage of polymyxin B failed to ameliorate the hyperdynamic circulation of PVL rats. In addition, long-term treatment with polymyxin B did not change systemic and portal hemodynamics in sham-operated rats. Plasma levels of endotoxin and tumor necrosis factor-alpha were comparable in PVL rats treated with long-term polymyxin B or N/S (p>0.05).

CONCLUSIONS

Our findings do not support the role of endotoxin in the hyperdynamic circulation of PVL rats.

Low incidence of transplant coronary artery disease in Chinese heart recipients

OBJECTIVES

This study sought to assess the incidence of transplant coronary artery disease (CAD) in Chinese heart recipients.

BACKGROUND

The prevalence of transplant CAD detected by angiography at 1, 2 and 4 years after heart transplantation was 11%, 22% and 45%, respectively. The incidence of transplant CAD in Chinese heart recipients has not been reported.

METHODS

For those recipients surviving for more than 1 year after transplantation, coronary angiography was performed annually for surveillance of transplant CAD. The recipient characteristics, donor characteristics, rejection episodes, medication and human leukocyte antigen (HLA) mismatches were recorded.

RESULTS

Fifty patients were included in this study. Thirteen (26%) recipients had ischemic heart disease. Two patients (4%) had active cytomegalovirus (CMV) infection after transplantation. The mean number of rejection episodes in the 1st year after transplantation was 1.15. Among 47 patients with complete data of donor and recipient histocompatibility antigens, there were seven patients (14.9%) with two or fewer HLA mismatches. Among 74 angiograms of 50 patients reviewed, only one patient had discrete stenosis less than 50% in the middle portion of the left anterior descending artery at 1 year after transplantation. The cumulative incidence of transplant CAD was 2% at 1 year and 2% at 2 and 4 years after transplantation.

CONCLUSIONS

The incidence of transplant CAD was low in Chinese heart transplant recipients. Low percentage of ischemic heart disease in recipients, low occurrence of active CMV infection and rejection episodes after transplantation, less racial disparity, and lower HLA mismatches may be the important factors.

The risk factors for gallstone disease among senior citizens: an Oriental study

BACKGROUND/AIMS

Few Occidental studies have addressed the risk factors for gallstone disease (GSD), among aged people. It is unknown whether these factors also present in the Orientals. Therefore, we studied the prevalence and risk factors for GSD among aged people in Taiwan.

METHODOLOGY

1441 aged subjects (> or = 60 years) who received a paid physical checkup at this hospital were investigated. Their demographic characteristics and biochemical parameters were recorded and compared. Ultrasonographic diagnosis revealed a normal gallbladder in 1092 subjects, gallbladder stones in 171, cholecystectomy for gallstones in 65, gallbladder polyps in 83, mixed gallbladder stones/polyps in 10, and miscellaneous results in 20. We enrolled 236 subjects showing either gallbladder stones or cholecystectomy for gallstones as the GSD group.

RESULTS

Excluding those subjects with mixed gallbladder stones/polyps, the overall prevalence of GSD in our series was 16.6%. Using multivariate analysis, the encountered factors manifesting risk for the development of GSD were old age (p<0.001), lower serum high-density lipoprotein level (p<0.01), diabetes mellitus (adjusted odds ratio: 2.127; p<0.001) and glucose intolerance (adjusted odds ratio: 1.954; p<0.001), whereas past history of alcohol consumption (adjusted odds ratio: 0.335; p<0.01) exhibited a protective effect against the development of GSD. Other demographic characteristics and biochemical parameters, such as body mass index, ABO blood type, cigarette smoking, blood pressure, serum cholesterol level, hepatitis B virus carrier, liver function, and parity, did not have any correlation to GSD.

CONCLUSIONS

Among the aged senior citizens in Taiwan, individuals with old age, lower serum high-density lipoprotein level, diabetes and glucose intolerance are at high risk for developing GSD.

Plasma concentrations of interferon-alpha in patients with liver cirrhosis: relationship to systemic and portal hemodynamics

BACKGROUND

Nitric oxide (NO) plays an important role in the pathogenesis of the hyperdynamic circulation observed in portal hypertensive states. Interferon (IFN)-alpha can stimulate NO formation directly or indirectly via cytokines. However, IFN-alpha concentrations seem to increase or decrease in cirrhotic patients. This study investigated the plasma concentration of IFN-alpha in patients with cirrhosis and its relationship to systemic and portal hemodynamics.

METHODS

Thirty-six patients with cirrhosis and 47 healthy controls had blood samples taken for the determination of plasma concentrations of IFN-alpha by enzyme-linked immunosorbent assay. Systemic and portal hemodynamics were measured in patients with cirrhosis on the same day of blood sampling using Swan-Ganz catheterization and the thermodilution technique.

RESULTS

As compared with healthy subjects, patients with cirrhosis demonstrated a significantly higher IFN-alpha detectable rate (> 3 pg/ml, 14.9% vs 36.1%, p < 0.05). In cirrhotic patients, the IFN-alpha detectable rates were similar between those with and without decompensation, a hepatic venous pressure gradient greater than 12 mmHg, or the presence of large esophageal varices (p > 0.05). There was no significant difference in the systemic vascular resistance or hepatic venous pressure gradient between cirrhotic patients with and without a detectable plasma IFN-alpha concentration.

CONCLUSIONS

Plasma IFN-alpha concentrations tended to increase in patients with cirrhosis. However, IFN-alpha concentrations do not play a role in the hyperdynamic circulation observed in patients with cirrhosis.

Developmental effects of phenytoin may differ depending on sex of offspring

Phenytoin (sodium salt), a developmental neurotoxicant, was administered orally by gavage (50-150 mg/kg) to pregnant rats on days 7-18 of gestation. Various developmental and behavioral indices were evaluated. Results indicated that phenytoin produced decreases in maternal and pup body weight gains, pup hindbrain, and F1 adult forebrain, whole brain, and cerebellar weights. Behavioral/developmental effects included performance deficits in a modified Morris water maze assay, in air righting and auditory startle responses, and increases in locomotor activity, accelerated eye opening, incisor eruption, negative geotaxis, and olfactory orientation. Female offspring appeared to be more severely affected when measuring incisor eruption, negative geotaxis, air righting, reactivity, and locomotor and maze activity. Males appeared to be more affected when measuring eye opening, olfactory orientation, and decreases in startle response. This study suggests that prenatal phenytoin exposure may result in developmental changes and behavioral deficits that may differ depending on the sex of the offspring.

Brominated 7-hydroxycoumarin-4-ylmethyls: photolabile protecting groups with biologically useful cross-sections for two photon photolysis

Photochemical release (uncaging) of bioactive messengers with three-dimensional spatial resolution in light-scattering media would be greatly facilitated if the photolysis could be powered by pairs of IR photons rather than the customary single UV photons. The quadratic dependence on light intensity would confine the photolysis to the focus point of the laser, and the longer wavelengths would be much less affected by scattering. However, previous caged messengers have had very small cross sections for two-photon excitation in the IR region. We now show that brominated 7-hydroxycoumarin-4-ylmethyl esters and carbamates efficiently release carboxylates and amines on photolysis, with one- and two-photon cross sections up to one or two orders of magnitude better than previously available. These advantages are demonstrated on neurons in brain slices from rat cortex and hippocampus excited by glutamate uncaged from N-(6-bromo-7-hydroxycoumarin-4-ylmethoxycarbonyl)-L-glutamate (Bhc-glu). Conventional UV photolysis of Bhc-glu requires less than one-fifth the intensities needed by one of the best previous caged glutamates, gamma-(alpha-carboxy-2-nitrobenzyl)-L-glutamate (CNB-glu). Two-photon photolysis with raster-scanned femtosecond IR pulses gives the first three-dimensionally resolved maps of the glutamate sensitivity of neurons in intact slices. Bhc-glu and analogs should allow more efficient and three-dimensionally localized uncaging and photocleavage, not only in cell biology and neurobiology but also in many technological applications.

Editing of cytochrome b mRNA in physarum mitochondria

The reading frame in the mRNA for the cytochrome b apoprotein in mitochondria of Physarum polycephalum is created by the insertion of 43 nucleotides in the mRNA relative to the mtDNA sequence encoding it (RNA editing). Most of these insertions (31) are single cytidines; however, single uridines are inserted at six sites, and the dinucleotides, CU and GC, are inserted at two sites and one site, respectively. These insertions create a 392-codon reading frame in the mature mRNA. The amino acid sequence inferred from this reading frame has similarity to cytochrome b apoproteins encoded by other mtDNAs. The insertions are quite evenly distributed throughout the length of the reading frame with an average spacing of 27 nucleotides. This mRNA has the highest percentage (23%) of noncytidine insertions of any Physarum RNA characterized to date. cDNAs corresponding to partially edited RNAs can be enriched by selective amplification. Some cDNAs that lack the GC dinucleotide insertion are fully edited at sites flanking the GC dinucleotide insertion site. Similarly some cDNAs lack the CT dinucleotide insertion or have a CC or TT insertion flanked by a fully edited sequence. These results imply that dinucleotide editing occurs by a process separate from the global insertion of cytidines.

An outbreak of enterically transmitted non-A, non-E viral hepatitis

Patients with isolated serum transaminase elevations of unknown cause are common in China. An outbreak of such disease took place in a technicians' school during 1996. To define the epidemic and determine the etiology, a study was carried out, which included investigation of epidemiological, clinical and histological features. The symptoms of this disease were mild. The major clinical feature was transaminase elevation, and all serum markers of known hepatitis viruses were negative. Although the course of disease in most patients was self-limiting, in a few it was prolonged and relapsed. Histological findings were mild portal hepatitis or non-specific reactive hepatitis. The disease first appeared in 1994, and this outbreak occurred after October 1996. A total of 381 people were affected and the prevalence was as high as 60.7%. Casual contact and small-scale food transmission were considered to be risk factors for infection and the epidemic was under control 2 months later following the introduction of preventive measures for gastroenteric infection. Viral genomic fragments from the so-called transfusion-transmitted virus (TTV) were detected in acute-phase sera and stool samples collected 2 weeks before onset. Therefore, this disease outbreak might be another form of enterically transmitted viral hepatitis, not related to hepatitis A and E.

A Java speech implementation of the Mini Mental Status Exam

The Folstein Mini Mental Status Exam (MMSE) is a simple, widely used, verbally administered test to assess cognitive function. The Java Speech Application Programming Interface (JSAPI) is a new, cross-platform interface for both speech recognition and speech synthesis in the Java environment. To evaluate the suitability of the JSAPI for interactive, patient interview applications, a JSAPI implementation of the MMSE was developed. The MMSE contains questions that vary in structure in order to assess different cognitive functions. This question variability provided an excellent test-bed to evaluate the strengths and weaknesses of JSAPI. The application is based on Java platform 2 and a JSAPI interface to the IBM ViaVoice recognition engine. Design and implementations issues are discussed. Preliminary usability studies demonstrate that an automated MMSE maybe a useful screening tool for cognitive disorders and changes.

Prophylactic octreotide reduces the severity of histopathologic changes and hemodynamic shock in early taurodeoxycholate-induced experimental pancreatitis

The findings related to the effects of somatostain and octreotide in experimental and clinical acute pancreatitis are so far inconclusive. In this study, we examined the early effects of prophylactic octreotide in acute experimental pancreatitis. Serum levels of amylase and lipase, pancreatic histopathology and systemic hemodynamic profiles, including mean arterial pressure, cardiac index, systemic vascular resistance and heart rate, were evaluated 5 hours after glycodeoxycholic acid (GDOC) or sodium taurodeoxycholate (TDC)-induced pancreatitis with or without prophylactic octreotide (10 micrograms/Kg) in rats, GDOC and TDC induced mild and severe pancreatitis, respectively. Octreotide significantly reduced serum levels of amylase and lipase at 5 hours in GDOC and TDC-induced pancreatitis. Octreotide significantly reduced the severity of pancreatic edema, necrosis and hemorrhage in TDC-induced pancreatitis. In addition, hemodynamic shock in TDC-induced pancreatitis was improved significantly by the administration of octreotide (mean arterial pressure 70.3 +/- 7.7 vs. 95.0 +/- 3.5 mmHg, p < 0.05; cardiac index 16.7 +/- 2.5 vs. 24.0 +/- 5.1 ml.min-1. 100 g-1, p < 0.05). However, octreotide did not show significant beneficial effect in pancreatic histopathology and hemodynamics in GDOC-induced pancreatitis. Thus we conclude that prophylactic octreotide improves pancreatic histopathology and hemodynamic shock in TDC-induced pancreatitis.

Proinflammatory cytokines in early assessment of the prognosis of acute pancreatitis

OBJECTIVE

Proinflammatory cytokines are involved in the pathogenesis of acute pancreatitis. The value of serum levels of tumor necrosis factor-alpha, interleukin-1-beta, interleukin-6, and interleukin-8 in predicting the outcome of acute pancreatitis was evaluated.

METHODS

In 50 patients with acute pancreatitis, the serum concentrations of tumor necrosis factor-alpha, interleukin-1-beta, interleukin-6, interleukin-8, and C-reactive protein were determined on days 1, 2, 3, 4, and 7 after admission. Acute Physiology and Chronic Health Evaluation (APACHE II) scores were recorded on days 1, 2, and 3.

RESULTS

Serum concentrations of interleukin-1-beta, interleukin-6, interleukin-8, and C-reactive protein on days 1-7 were significantly higher in patients with severe pancreatitis than in patients with mild pancreatitis. Patients with severe attacks had significantly elevated serum tumor necrosis factor-alpha concentrations on days 1-3 compared with those with mild attacks, but not on days 4 and 7. The median peak value of tumor necrosis factor-alpha, interleukin-1-beta, interleukin-6, and interleukin-8 was reached on day 1, in contrast to the median peak of C-reactive protein, which was reached on day 2. Using cutoff levels of 12 pg/ml for tumor necrosis factor-alpha, 1 pg/ml for interleukin-1-beta, 400 pg/ml for interleukin-6, 100 pg/ml for interleukin-8, 12 mg/dl for C-reactive protein, and 10 for the Acute Physiology and Chronic Health Evaluation (APACHE II) score, the accuracy rates for detecting severe pancreatitis were 72%, 82%, 88%, 74%, 80%, and 72%, respectively, on day 1 and 78%, 74%, 80%, 76%, 80%, and 78%, respectively, on day 2.

CONCLUSION

Among the proinflammatory cytokines, interleukin-6 is the most useful parameter for early prediction of the prognosis of acute pancreatitis.

Proximal femoral dimension in elderly Chinese women with hip fractures in Taiwan

To investigate the relationship between proximal femoral geometry and the occurrence of hip fracture, we compared the geometry of contralateral normal hips of 120 elderly Chinese women with hip fractures, including 63 femoral neck fractures (group A) and 57 intertrochanteric fractures (group B) due to minor trauma, with that of 72 normal elderly Chinese women (group C). The mean ages for group A, B and C subjects were 77.3, 79.7 and 72.9 years, respectively. The femoral neck length (NL), neck width (NW), diameter of femoral head, femoral shaft width just below the lesser trochanter, and neck-shaft angle (theta;) were measured on the anteroposterior plain pelvic radiographs. The mean +/- SD of NL for group A was 50.4 +/- 3.3 mm; for group B, 50.6 +/- 3.1 mm; and for group C, 48.8 +/- 3.6 mm. Statistical analysis by ANOCOVA and regression showed that only NL of women with hip fractures was significantly longer than controls after correction for age, body height and weight (p <0.01). However, the difference in NL between group A and group B was not significant. By linear regression, the probability of fracture increased only with older age (p <0.001), longer NL (p <0.005) and lighter body weight (p <0.05). By logistic regression, each standard deviation increase in NL increased the risk of hip fracture (age-adjusted odds ratio 1.84; 95% CI, 1.11-3.06). The results confirm the relationship between proximal femoral geometry and the occurrence of hip fracture in elderly Chinese women in Taiwan.

Video-assisted endoscopic saphenous vein harvesting for coronary artery bypass grafting

Saphenous vein grafts for coronary artery bypass can be harvested by means of the traditional long incision method, the skin bridge method, or a newly developed endoscopic technique. We applied the endoscopic technique to reduce the length of leg incision and to decrease the frequency of complications. Between September and December 1996, 47 patients underwent coronary artery bypass grafts, 17 of whom volunteered to undergo saphenous vein harvest with the Endopath video-assisted endoscopic saphenous vein harvest (ESVH) system; the other 30 patients underwent the traditional long incision harvest procedure. A total of 22 saphenous veins were harvested from the 17 patients who underwent ESVH. The mean length of the leg wound was 5.8 +/- 1.3 cm and the mean length of the vein harvested was 32.9 +/- 3.4 cm (wound/vein length ratio 17.6%). The wound/vein length ratio of the 30 patients who underwent the traditional open harvest method was 91.5% (30.8 +/- 2.2 cm/34.1 +/- 3.0 cm). ESVH failed and was converted to the conventional method in two cases. The mean time required to harvest the saphenous vein was 72.7 +/- 20.8 minutes in the ESVH group and 45.8 +/- 12.5 minutes in the open surgery group. No wound complications were noted in the ESVH group, except for ecchymosis in three cases. Five patients in the open surgery group had wound discharge (17%). The length of hospital stay was shorter (10.5 +/- 2.6 days vs 15.8 +/- 4.2 days) and fewer analgesics were used in the ESVH group. The rate of cardiac complications was not different between the two groups. Examination of the vein graft under light microscopy also did not reveal any differences. We conclude that the endoscopic technique can provide adequate vein grafts for use in coronary artery bypass grafting and reduce the leg wound complication rate, hospital stay, and use of analgesics.

Aminoguanidine ameliorates splanchnic hyposensitivity to glypressin in a haemorrhage-transfused rat model of portal hypertension

1. Hyposensitivity to vasopressin is a well-documented phenomenon in animals with portal hypertension and patients with cirrhosis subjected to haemorrhage. Excessive formation of nitric oxide is at least partly responsible for the vascular hyporesponsiveness to vasoconstrictors observed in experimental portal hypertension or in rats with haemorrhagic shock. This study investigated whether addition of aminoguanidine, a preferential inducible nitric oxide synthase inhibitor, to glypressin (a long-acting vasopressin analogue) could enhance its portal hypotensive effect in portal-hypertensive rats with bleeding.2. Portal hypertension was induced by partial portal vein ligation. Fourteen days after operation, systemic and portal haemodynamics were measured in stable or bleeding portal vein-ligated rats receiving intravenous glypressin (0.07 mg/kg) or aminoguanidine (70 mg/kg) followed by glypressin infusion. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of glypressin or aminoguanidine.3. Glypressin resulted in a significantly greater decrease in portal pressure in portal vein-ligated rats without bleeding than in those with bleeding (P<0.001). In contrast, glypressin induced similar changes in mean arterial pressure between the two groups (P>0.05). The addition of aminoguanidine significantly potentiated the portal-hypotensive effect of glypressin in bleeding portal vein-ligated rats (P<0.005) without an effect on the changes in mean arterial pressure induced by glypressin infusion (P>0.05).4. Splanchnic hyposensitivity to glypressin exists in a haemorrhage-transfused rat model of portal hypertension. This hyposensitivity can be ameliorated by the administration of aminoguanidine.

Alterations of the PPP2R1B gene in human lung and colon cancer

The PPP2R1B gene, which encodes the beta isoform of the A subunit of the serine/threonine protein phosphatase 2A (PP2A), was identified as a putative human tumor suppressor gene. Sequencing of the PPP2R1B gene, located on human chromosome 11q22-24, revealed somatic alterations in 15% (5 out of 33) of primary lung tumors, 6% (4 out of 70) of lung tumor-derived cell lines, and 15% (2 out of 13) of primary colon tumors. One deletion mutation generated a truncated PP2A-Abeta protein that was unable to bind to the catalytic subunit of the PP2A holoenzyme. The PP2R1B gene product may suppress tumor development through its role in cell cycle regulation and cellular growth control.

Development of Bacillus thuringiensis fermentation and process control from a practical perspective

Bacillus thuringiensis (Bt) is the most widely used biopesticide producer in the biological control market. It is very critical for the Bt pesticide industry to be able to achieve a high yield in the Bt fermentation process in order to reduce its cost and compete with chemical pesticides in the market. We review the overall development of Bt fermentation process research and provide our point of view for the future research opportunities and potential improvements. This minireview covers the areas of fermentation physiology, growth dynamics and high-yield process control. It is pointed out that many studies aimed to improve spore count and process research focusing on toxin protein yield is lacking. In addition, significant development opportunities reside in the process development for the genetically engineered Bt strains expressing multiple toxin proteins.

HBV core promoter mutations prevail in patients with hepatocellular carcinoma from Guangxi, China

The development of primary liver cancer frequently is associated with persistent HBV infection, and tumours may arise in individuals who are anti-HBe positive. However, it is unclear whether viruses with an HBeAg-negative phenotype are associated with tumour development or are selected, during seroconversion, after chromosomal integration of wild-type viral DNA. In order to investigate the temporal evolution of the HBV genome in such individuals, the polymerase chain reaction was used to amplify HBV DNA from tumour tissue and serum of 14 patients from Guangxi, China with hepatocellular carcinoma. Comparison of nucleotide and amino acid sequences of the precore and proximal core region of HBV from the two sites in each patient produced evidence of divergence following integration in the tumour, but in most cases, HBeAg-negativity could not be explained by precore mutations. Sequences from the core promoter region were therefore examined and mutations were found in the majority, which are believed to upregulate transcription of the core (and pregenomic) RNA but to downregulate precore mRNA. To determine whether this finding merely reflected sequence variation among geographical isolates of HBV, the same region of HBV DNA from asymptomatic controls was sequenced and these mutations were found to be rare. We hypothesise that HBV with the core promoter mutations replicates at higher levels than the wild type, with the consequence that more integrations occur into the hepatocyte chromosomes during the early stages of infection. These hepatocytes may expand clonally and be targets for further mutagenic events leading to tumour development.

Transcriptional and posttranscriptional control of tyrosine hydroxylase gene expression during persistent stimulation of pituitary adenylate cyclase-activating polypeptide receptors on PC12 cells: regulation by protein kinase A-dependent and protein kinase A-independent pathways

Pituitary adenylate cyclase-activating polypeptide (PACAP) stimulates catecholamine release and biosynthesis in sympathetic postganglionic cells. Moreover, PACAP receptor activation in cultured adrenal chromaffin and superior cervical ganglion cells has been reported to increase the expression of the gene coding for tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis. However, the relative contribution of transcriptional and posttranscriptional mechanisms to the effects of PACAP on TH gene expression has not been evaluated. Therefore, in this study we compared the temporal effects of PACAP on TH gene transcription with the duration of its effects on TH mRNA levels. We had previously shown that vasoactive intestinal polypeptide, peptide histidine isoleucine, and secretin, peptides closely related to PACAP, induce TH gene expression through a cyclic AMP (cAMP)-dependent pathway. Therefore, using a mutant PC12 cell line deficient in cAMP-dependent protein kinase II (PKA), we also evaluated the role of the cAMP pathway in the effect of PACAP on TH gene expression. Continuous treatment of wild-type PC12 cells with PACAP (1 nM) increased TH mRNA levels maximally by 12 h and maintained TH mRNA at near maximal levels for at least 2 days. In contrast, the rate of TH gene transcription, as measured by a nuclear run-on assay, was maximal by 1 h and returned to basal levels by 3 h. The fact that a new steady-state level of TH mRNA was achieved and maintained for days in the absence of a sustained increase in TH gene transcription supports the involvement of posttranscriptional mechanisms. Removal of PACAP after 12 h, a time at which TH gene transcription was at basal levels, resulted in a subsequent return of TH mRNA to unstimulated levels within 36 h. Thus, continuous PACAP stimulation is required to maintain sustained increases in TH mRNA levels in the absence of a sustained elevation of transcription. To examine the role of the cAMP pathway in these effects, we compared the effects of PACAP in wild-type PC12 cells and in a mutant PC12 cell line (A126-1B2) that is deficient in PKA. PACAP failed to stimulate either TH mRNA levels or TH gene transcription in the mutant cells. In contrast to the effects of PACAP, dexamethasone increased TH mRNA levels by the same magnitude in both cell lines. It is noteworthy that stimulation of the PKA-deficient mutant cells with a combination of PACAP and dexamethasone (1 microM) produced a synergistic increase in TH mRNA levels, which was nearly twice that induced by dexamethasone stimulation alone. This synergistic effect was not transcriptionally mediated. The effect of the combined treatment on TH gene transcription was identical to the effect of dexamethasone alone. Taken together, these data indicate that PACAP regulates TH gene expression through a transcriptional mechanism requiring an intact cAMP pathway and through posttranscriptional mechanisms under the control of a cAMP-independent pathway(s).

Phase II and pharmacokinetic study of paclitaxel therapy for unresectable hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is a common lethal disease in Asia and there is no effective chemotherapy. Identification of new effective drugs in the treatment of inoperable HCC is urgently need. This is a phase II clinical study to investigate the efficacy, toxicity and pharmacokinetics of paclitaxel in HCC patients. Twenty patients with measurable, unresectable HCC, normal serum bilirubin, normal bone marrow and renal functions were studied. Paclitaxel 175 mg m(-2) was given intravenously over 3 h every 3 weeks. No complete or partial responses were observed. Five patients had stable disease. Major treatment toxicities (grade 3-4) were neutropenia (25%), thrombocytopenia (15%), infection (10%) and allergy (10%). Treatment-related deaths occurred in two patients. The median survival was 12 weeks (range 1-36). Paclitaxel is metabolized by the liver and the pharmacokinetics of paclitaxel in cancer patients with liver involvement or impairment may be important clinically. Pharmacokinetic study was completed in 13 HCC patients. The paclitaxel area under the curve was significantly increased (P < 0.02), clearance decreased (P < 0.02) and treatment-related deaths increased (P = 0.03) in patients with hepatic impairment. In conclusion, paclitaxel in this dose and schedule has no significant anti-cancer effect in HCC patients. Paclitaxel should be used with caution in cancer patients with liver impairment.

Recurrent spontaneous bacterial empyema in cirrhosis: a case report

Spontaneous bacterial empyema occurs in about 0.4% of cirrhotic patients, but recurrent attack has rarely been reported. Herein we report a case of repeat episodes of spontaneous bacterial empyema. The patient presented with fever, shortness of breath and three episodes of spontaneous bacterial empyema (accompanied by septic shock in two episodes) within six months. Chest roentgenography showed massive right-side pleural effusion. Thoracentesis yielded pleural effusion containing a neutrophil count of more than 500/microliter. A blood culture grew non-O1 Vibrio cholerae in one episode and the pleural effusion culture grew Aeromonas hydrophila. A chest-tube was inserted during the latest episode due to a low pH and glucose concentration in the pleural fluid. The patient recovered well after medical treatment. The etiology, diagnosis and management of spontaneous bacterial empyema are discussed.

Oxidative stress: an important phenomenon with pathogenetic significance in the progression of acute pancreatitis

BACKGROUND

Reactive oxygen species and related oxidative damage have been implicated in the initiation of acute pancreatitis. Changes in these parameters during disease progression merit further investigation.

AIMS

To evaluate changes and the clinical relevance of superoxide radicals, endogenous antioxidants, and lipid peroxidation during the course of acute pancreatitis.

PATIENTS AND METHODS

Superoxide radicals (measured as lucigenin amplified chemiluminescence), ascorbic acid, dehydroascorbic acid, alpha tocopherol, and lipid peroxidation (measured as thiobarbiturate reactive substances) were analysed in blood samples from 56 healthy subjects, 30 patients with mild acute pancreatitis, and 23 patients with severe acute pancreatitis. The association with grades of disease severity was analysed. Measurements were repeated one and two weeks after onset of pancreatitis.

RESULTS

In the blood from patients with acute pancreatitis, there were increased levels of the superoxide radical as well as lipid peroxides. There was notable depletion of ascorbic acid and an increased fraction of dehydroascorbic acid. Changes in alpha tocopherol were not great except in one case with poor prognosis. Differences between severe and mild acute pancreatitis were significant (p < 0.01). Variable but significant correlations with disease severity scores were found for most of these markers. The normalisation of these indexes postdated clinical recovery one or two weeks after onset of disease.

CONCLUSIONS

Heightened oxidative stress appears early in the course of acute pancreatitis and lasts longer than the clinical manifestations. The dependence of disease severity on the imbalance between oxidants and natural defences suggests that oxidative stress may have a pivotal role in the progression of pancreatitis and may provide a target for treatment.