Potential of methacrylated acemannan for exerting antioxidant-, cell proliferation-, and cell migration-inducing activities in vitro

BACKGROUND

Acemannan is an acetylated polysaccharide of Aloe vera extract with antimicrobial, antitumor, antiviral, and antioxidant activities. This study aims to optimize the synthesis of acemannan from methacrylate powder using a simple method and characterize it for potential use as a wound-healing agent.

METHODS

Acemannan was purified from methacrylated acemannan and characterized using high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), and ¹H-nuclear magnetic resonance (NMR). 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays were performed to investigate the antioxidant activity of acemannan and its effects on cell proliferation and oxidative stress damage, respectively. Further, a migration assay was conducted to determine the wound healing properties of acemannan.

RESULTS

We successfully optimized the synthesis of acemannan from methacrylate powder using a simple method. Our results demonstrated that methacrylated acemannan was identified as a polysaccharide with an acetylation degree similar to that in A. vera, with the FTIR revealing peaks at 1739.94 cm^-1 (C = O stretching vibration), 1370 cm^-1 (deformation of the H-C-OH bonds), and 1370 cm^-1 (C-O-C asymmetric stretching vibration); ¹H NMR showed an acetylation degree of 1.202. The DPPH results showed the highest antioxidant activity of acemannan with a 45% radical clearance rate, compared to malvidin, CoQ10, and water. Moreover, 2000 µg/mL acemannan showed the most optimal concentration for inducing cell proliferation, while 5 µg/mL acemannan induced the highest cell migration after 3 h. In addition, MTT assay findings showed that after 24 h, acemannan treatment successfully recovered cell damage due to H₂O₂ pre-treatment.

CONCLUSION

Our study provides a suitable technique for effective acemannan production and presents acemannan as a potential agent for use in accelerating wound healing through its antioxidant properties, as well as cell proliferation- and migration-inducing activities.

Increased incidence of neurogenic bladder after radical hysterectomy for cervical cancer: A nationwide population-based cohort study

BACKGROUND

The effect of radical hysterectomy for patients with cervical cancer on voiding function remains controversial. The purpose of this study was to examine the association between radical hysterectomy for patients with cervical cancer and the odds of developing neurogenic bladder by using data from the National Health Insurance Research Database (NHIRD) in Taiwan.

METHODS

We identified 17 936 patients who underwent radical hysterectomy for cervical cancer between 2000 and 2013 among inpatients registered in the Longitudinal Health Insurance Database in Taiwan. Of the patients, those diagnosed as having cervical cancer without radical hysterectomy were selected and compared as a matched control group. Patients diagnosed as having cervical cancer before the index date, those with neurogenic bladder dysfunction before tracking, and those aged <20 years were excluded. The hazard ratios (HRs) of neurogenic bladder and other variants of interest were further calculated using a multivariate Cox regression analysis. The cutoff p value of <0.05 was regarded as statistically significant.

RESULTS

The adjusted HR (aHR) of subsequent neurogenic bladder was higher in the hysterectomy group (aHR = 1.205; 95% CI, 1.086-1.440; p = 0.029) than in the control group during the follow-up period. As to the age subgroups, the patients aged 20 to 44 years (aHR = 3.321, p = 0.001) had a significantly increased risk of developing neurogenic bladder after radical hysterectomy as compared with those aged 45 to 64 years (aHR = 1.193, p = 0.012).

CONCLUSION

Patients with cervical cancer undergoing radical hysterectomy have an increased risk of neurogenic bladder, which may result from nerve denervation caused by the operation. These patients should be informed of the potential risk of voiding dysfunction during discussion of the subsequent management for cervical cancer.

A Rare Case Report of Metastatic Urothelial Carcinoma to Skull with Significant Reossification after Pembrolizumab

Background: Urothelial carcinoma ranks as the fourth most common cancer in men in the U.S; upon diagnosis, 10-15% have metastasized, mostly to lymph nodes, liver, lung, bone, and adrenal glands. Very few cases of skull invasion have been reported, and there is no established definite treatment. Case presentation: A 64-year-old Taiwanese male presented with metastatic urothelial carcinoma (mUC) of bladder with skull invasion. A sunken forehead without painful sensation could be palpated. After failure of chemotherapy, the patient received immunotherapy pembrolizumab, and complete remission of distant metastasis with reossification of osteolytic skull were noted. Conclusion: Immunotherapy has been reported to show significant remission in mUC, but mostly in solid organs or bone. While skull metastasis usually suggests late progression of the disease, immunotherapy has fewer systemic adverse effects than chemotherapy, and should be taken into consideration as a first-line therapy.

Kidney Transplantation from an extracorporeal membrane oxygenation-supported brain-dead donor: A case report

RATIONALE

Extracorporeal membrane oxygenation (ECMO) can deliver effective respiratory and circulatory maintenance to organ donors, improve organ function, and shorten warm ischemic time before harvesting. However, ECMO-supported brain-dead donors (DBDs) still have a high risk of acute kidney injury related to decreased renal oxygen delivery and inflammatory damage, which may cause early graft failure.

PATIENT CONCERNS

Kidney transplantation from an ECMO-supported DBD.

DIAGNOSES

We found an extremely abnormal "very dark blue" appearance of the graft kidneys from an ECMO-supported DBD during kidney procurement.

INTERVENTIONS

Rather than discarding the graft kidneys, we performed an on-table biopsy. Pretransplant biopsy results revealed minimal interstitial fibrosis in the section of these graft kidneys.

OUTCOMES

Two candidates received graft kidneys, and the two grafts remained functional until the 8-month follow-up.

LESSONS

Currently, there is no standard method for evaluating graft kidney function of ECMO-supported DBDs. Regardless of the donors' preoperative serum creatinine (SCr) level, estimated glomerular filtration rate (eGFR), or gross appearance of the graft kidney, we believe that it is more reliable to include pretransplant biopsy as a criterion in clinical practice to safely accept kidneys from ECMO-supported DBDs.

Myocardial infarction and ischemic hepatitis complicated by postpartum hemorrhage

OBJECTIVE

To present a rare case of life-threatening postpartum hemorrhage due to uterine atony complicated by acute myocardial infarction and ischemic hepatitis.

CASE REPORT

A 37-year-old parturient, gravida 1 para 0, presented with symptoms and signs of shock due to postpartum hemorrhage after delivery. Ischemic hepatitis, pulmonary edema, and adult respiratory distress syndrome developed the following morning. On the 7(th) postpartum day, she developed chest pain and was subsequently diagnosed with acute inferior myocardial infarction based on serial changes on the electrocardiogram (ECG) and myocardial enzymes. The clinical condition improved after a series of resuscitative efforts and percutaneous transluminal coronary angioplasty.

CONCLUSION

The presented case demonstrated that when hypovolemic shock develops with complications of pulmonary edema or ischemic hepatitis, the possibility of cardiovascular disease should be immediately investigated and preventive measures initiated.

Urine specific gravity as a predictor of early neurological deterioration in acute ischemic stroke

We previously found that a blood urea nitrogen/creatinine (BUN/Cr) ratio>15 is an independent predictor of early neurological deterioration after acute ischemic stroke, which suggests that dehydration may be a cause of early deterioration. The aim of this study was to determine whether urine specific gravity, which is another indicator of hydration status and one that is more easily obtained, is also an independent predictor of early deterioration or stroke-in-evolution (SIE). Demographic and clinical data were recorded at admission from patients with acute ischemic stroke who were prospectively enrolled from October 2007 to June 2010. We compared patients with and without stroke-in-evolution (based on an increase of 3 points or more points on the National Institutes of Health Stroke Scale within 3 days). Univariate and multivariate statistical analyses were carried out. A total of 317 patients (43 SIE and 274 non-SIE) were enrolled; the first 196 patients comprised the cohort of our previous study. The only two independent predictors of early deterioration or SIE were BUN/Cr>15 and urine specific gravity>1.010. After adjusting for age and gender, patients with a urine specific gravity>1.010 were 2.78 times more likely to develop SIE (95% CI=1.11-6.96; P=0.030). Urine specific gravity may be useful as an early predictor of early deterioration in patients with acute ischemic stroke. Patients with urine specific gravity ≤ 1.010 therefore may have a reduced likelihood of early neurological deterioration.

A CD14 promoter polymorphism is associated with CD14 expression and Chlamydia-stimulated TNFα production

CD14, a pattern recognition receptor on monocyte and macrophage, plays a central role in innate immunity through recognition of bacterial lipopolysaccharide and initiation of inflammatory response. Recently, CD14/-260C>T promoter gene polymorphism has been found to be related to a risk of inflammatory diseases. Our results showed that the C allele frequency among Chinese in Taiwan was lower than those in Western countries. The membrane CD14 expression was significantly higher in TT as compared with CT and CC genotypes (P=0.034, 0.044, respectively). There was a higher level of soluble CD14 in TT and CT genotypes than in CC genotypes. In addition, TNFalpha production in whole blood was significantly higher in TT genotype than in CC genotype after stimulation by Chlamydiae. In conclusion, the single base pair polymorphism of CD14 promoter gene is associated with CD14 expression and Chlamydia-stimulated TNFalpha production, and may thus play some role in the chlamydia-induced inflammatory response.

Nonlinear multiwavelength conversion based on an aperiodic optical superlattice in lithium niobate

We have demonstrated what is to our knowledge the first successful achievement of multiwavelength conversion in an aperiodic optical superlattice (AOS) lithium niobate crystal with equalized gain. The two AOS devices in our experiment, numerically synthesized from 2857 crystal blocks with a unit block thickness of 3.5 microm, have fundamental wavelengths of 1540 and 1545 nm for double-wavelength second-harmonic generation (SHG) and of 1540, 1545, and 1553 nm for triple-wavelength SHG at 50 degrees C. Our experiment and simulation show that the output spectrum of an AOS wavelength converter is fairly insensitive to typical fabrication errors.

Determination and pharmacokinetic study of meropenem in rat bile using on-line microdialysis and liquid chromatography

Meropenem is a carbapenem antibiotic with a wide spectrum of activity against both Gram-positive and Gram-negative bacteria. Because of its clinical efficacy, meropenem is an excellent choice for the treatment of serious infections in both adults and children. The knowledge of tissue concentrations of antibiotic in an infection site is valuable for the prediction of treatment outcome. To investigate the biliary disposition of meropenem, we utilized a minimally invasive sampling technique with a shunt linear microdialysis probe for continuous sampling in the biliary excretion studies. Analysis of meropenem in the dialysates was achieved using a LiChrosorb RP-18 column (Merck, 250 x 4.6 mm I.D.; particle size 5 microm) maintained at ambient temperature. The mobile phase was 50 mM monosodium phosphoric acid-methanol (80:20, v/v, pH 3.0). The UV detector wavelength was set at 298 nm. The area under the concentration-time curve and elimination half-lives of meropenem were about 6144 +/- 1494 min microg/ml and 61 +/- 17 min, respectively. This study represents a successful application of the microdialysis technique, which is an effective method for pharmacokinetic and biliary drug excretion studies.

Ascending cholangitis provokes IL-8 and MCP-1 expression and promotes inflammatory cell infiltration in the cholestatic rat liver

BACKGROUND/PURPOSE

Postoperative cholangitis is one of the most common complications after bile duct reconstruction. The pathogenesis and early consequences of ascending cholangitis still are unidentified.

METHODS

Male Sprague-Dawley rats were divided into 5 treatment groups: control (n = 4), blood sampling and liver biopsy only; group I, [BDL/Eschericha coli; n = 6], ligation of common bile duct (BDL) for a week, followed by Roux-en-Y choledochojejunostomy (RYCJ) and injection of E coli (ATCC 25922) into Roux limb after 24 hours; group II, [BDL/NS; n = 5], same procedures as in group I, with injection of normal saline (NS) into Roux limb; group III, [SBDL/E coli; n = 6], primary RYCJ was constructed 1 week after sham ligation of common bile duct (SBDL) followed by the same treatment as group I; Group IV, [SBDL/N.S; n = 6], same procedures as in group III, but injecting NS into Roux limb. All animals were killed after 24 hours of treatment. Blood was sampled for culture and serum cytokine levels. The liver was harvested for quantitative bacterial culture, as well as for MCP-1, interleukin (IL)-8 (CINC in the rat) and transforming growth factor beta1 mRNA expression by reverse transcriptase polymerase chain reaction (RT-PCR) and for immunohistochemistry. The choledochojejunostomy was resected for culture. Serum cytokine levels were detected by ELISA kits.

RESULTS

A significant increase of E coli ATCC 25922, occurred in the livers of group I rats, compared with group IV (P =.037). MCP-1 expression increased in all groups, compared with control (P =.000). The IL-8 mRNA expression was significantly higher in group I than in control (P =.021). The expression of TGF-beta1 mRNA was similar among the groups (P =.361), consistent with the immunohistochemistry results. The serum MCP-1 and IL-8 levels were higher in the 4 groups than in the control (P =.000) and were significantly higher in group I than in group IV (P =.001).

CONCLUSIONS

This study found that a significant colonization of E coli of the same strain was present in the cholestatic rat liver injected into the Roux limb, which was associated with a higher expression of liver MCP-1 and IL-8 mRNA, a significant increase of serum MCP-1 and IL-8, and a more evident inflammatory cell infiltration into the porta hepatis.

Effects of Paeoniae Radix, a traditional Chinese medicine, on the pharmacokinetics of phenytoin

BACKGROUND

Phenytoin (PHT), one of the most widely prescribed antiepileptic drugs, has been reported to be associated with numerous drug-drug interactions. However, there are far fewer reports about the pharmacokinetic interactions between PHT and traditional Chinese medicines (TCMs). Paeoniae Radix (PR), one of the well-known TCMs, is used as an adjunct in some epileptic patients.

OBJECTIVE

In the present work, we studied the influences of PR on the pharmacokinetics of PHT in rats to identify the possible interactions between PR and PHT.

METHOD

A single dose of PHT (100 mg/kg) alone or in combination with PR extract (300 mg/kg) was administered by gavage to male SD rats. Serial blood samples of PHT were obtained for up to 24 h post-administration and measured by high-performance liquid-chromatography. The free (unbound) plasma concentrations of PHT were determined by fluorescence polarization immunoassay. The plasma concentrations were used to construct pharmacokinetic profiles by plotting drug concentration-time curves. All data were subsequently processed by the computer program WINNONLIN. Statistical comparisons of pharmacokinetic parameters were performed with the unpaired Student t-test.

RESULTS

The mean maximum plasma concentration of PHT was attained 2 h after oral administration of PHT alone and 4-6 h after oral administration of PHT in combination with PR. The plasma level of PHT declined with a half-life of 5.38 h after PHT alone and 4.03 h after PHT and PR given together. No statistically significant differences were obtained in most of the pharmacokinetic parameters (Cmax, AUC, t1/2, MRT and CL/F) and protein binding rates of PHT between the two treatments. However, significant differences in Tmax and Vd/F between groups were noted.

CONCLUSION

The significant increase in Tmax indicated that simultaneous oral administration of PR delayed the absorption of PHT. The delayed absorption of PHT might lead to its slow onset of clinical effect. There were no significant differences in Cmax, AUC, t1/2, MRT and CL/F of PHT between the two groups, showing that PR could not significantly affect the extent of absorption, metabolism and elimination of PHT. No significant difference in protein binding rate was found, indicating that PR might not significantly alter the protein binding of PHT. While a significant decrease in Vd/F was noted, the mechanism underlying the apparently decreased Vd/F of PHT influenced by PR needs further study.

Effect of cyclosporine, a P-glycoprotein inhibitor, on the pharmacokinetics of cefepime in rat blood and brain: a microdialysis study

In clinical application, cefepime and cyclosporine are regularly combined in the treatment of organ transplant patients, so the interaction of these two drugs can be hypothesized. Therefore, the pharmacokinetics of cefepime alone and in combination with cyclosporine in rat using microdialysis coupled with HPLC-UV on-line system was evaluated in the study. Cefepime at three doses (20, 50, and 100 mg/kg) showed linear kinetics. After addition of cyclosporine, the mean residence time was increased from 34.9 min to 48.6 min (p<0.05, n=6), and the area under the concentration versus time curve (AUC) increased from 4775 min microg/ml to 6960 min microg/ml (p<0.01, n=6). While in the brain, AUC increased from 64.3 min microg/ml to 110.2 min microg/ml. In summary, cyclosporine (20 mg/kg) could significantly alter the simultaneously administered cefepime (50 mg/kg) unbound drug pharmacokinetic parameters in both blood and brain.

Determination and pharmacokinetic study of unbound cefepime in rat bile by liquid chromatography with on-line microdialysis

Biliary excretion and intestinal reabsorption in enterohepatic circulation play major dispositional roles for some drugs. To investigate biliary excretion of drug, we inserted a microdialysis probe into the bile common duct of rat between the liver and the duodenum. In order to avoid the obstruction of bile fluid or bile salt waste, a shunt linear microdialysis probe was used for simultaneous and continuous sampling following intravenous administration of cefepime (50 mg/kg, i.v.). Separation and quantitation of cefepime in the dialysates were achieved using a LiChrosorb RP-18 column (Merck; 250x4.6 mm I.D., particle size 5 microm) maintained at ambient temperature. Samples were eluted with a mobile phase containing 100 mM monosodium phosphoric acid (pH 3.0)-methanol (87:13, v/v). The UV detector wavelength was set at 270 nm. The result indicates that the elimination half-life of cefepime in bile was 64.01+/-9.32 min. This study also served as an example for the microdialysis application in the biliary excretion study of drug.

Lack of pharmacokinetic interaction between valproic acid and a traditional Chinese medicine, Paeoniae Radix, in healthy volunteers

BACKGROUND AND OBJECTIVE

In addition to the standard antiepileptic drugs, traditional Chinese medicines (TCMs) are used for the treatment of epilepsy in oriental countries. The interactions between antiepileptic drugs and TCMs represent a potential problem in clinical application. Because valproic acid (VPA), one of the most widely prescribed antiepileptic drugs, may be administered concomitantly with Paeoniae Radix (PR), one of the famous TCMs, in some epileptic patients, the present study was conducted to evaluate the influences of PR on the pharmacokinetics of VPA.

METHOD

The pharmacokinetics of VPA were investigated in a randomized, open-label, two-way crossover study. Six healthy volunteers received the following treatments in a crossover design: (i) 1.2 g extract powder of Paeoniae Radix once daily for 7 days and one 200 mg VPA gastro-resistant tablet on day 7 and (ii) one 200 mg VPA gastro-resistant tablet alone on day 7. Serial plasma samples were obtained on day 7. Total and free (unbound) VPA plasma concentrations were determined by fluorescence polarization immunoassay (FPIA). Safety measures included laboratory tests (haematology, serum chemistry and urinalysis) and adverse event monitoring. Statistical comparisons of pharmacokinetic parameters were performed with the Student paired t-test.

RESULTS

Overall clinical safety was satisfactory. The mean maximum plasma concentration of VPA was attained at within 6 h after oral administration of VPA alone and 3-4 h after oral administration of VPA in combination with PR. The plasma level of VPA declined with a half-life of 11.71 and 11.91 h, respectively. No statistically significant difference was obtained in any of the pharmacokinetic parameters (Tmax, Cmax, AUC, t1/2, MRT, CL/F and Vd/F) of VPA between the two treatments. Also, there was no significant difference in the protein binding rates of VPA.

CONCLUSION

PR did not significantly affect the absorption, distribution, metabolism and elimination of VPA in healthy volunteers.

Long-term treatment with warfarin in Chinese population

OBJECTIVE

To estimate the incidence of and risks for bleeding and thromboembolic events after warfarin anticoagulation. We also explored the dosage and international normalized ratio (INR) among Chinese patients during long-term warfarin therapy.

METHODS

The population in this retrospective study consisted of inpatients of the only medical center for northern Taipei City, whose initial course of warfarin therapy continued for more than four weeks. Enrollment began in June 1995 and ended in February 1996. Follow-up was completed in March 1998. Relevant data were collected by chart review. The rate of events was calculated using the Kaplan-Meier method, and risk factors were identified by the Cox proportional hazard model.

RESULTS

During the study period, 226 patients were identified. The total follow-up time was 248.7 patient-years. Sixty-one patients (27.0%) received anticoagulation for mechanical prosthetic valve, but their duration of therapy accounted for 48.6% of the total patient-years of follow-up. The starting dosage (mean +/- SD) was 3.4+/-1.4 mg/d (range 1.3-10); the maintenance dosage was 3.1+/-1.2 mg/d (range 1.2-7.7). There were 1060 dosing adjustments and 3398 INR measurements collected for these patients. The independent determinants of maintenance dosage were age, body weight, and indication of mechanical prosthetic valve. The INR was 1.9+/-0.5 (range 1.0-3.7). The cumulative probabilities for hemorrhage at 12, 24, and 34 months were 24.5%, 32.3%, and 38.4%, respectively. The corresponding figures for thromboembolism were 8.5%, 10.7%, and 10.7%, respectively. Three hemorrhages were fatal. After adjusting for other patient characteristics, increasing age was the only independent risk factor identified for bleeding.

CONCLUSIONS

Antithrombotic efficacy seemed to be maintained, although the mean INR was 1.9. Even so, the substantial incidence of bleeding, especially fatal bleeding, remains a concern. Low-intensity anticoagulation might be needed for Chinese patients during long-term warfarin therapy.

Simultaneous determination of unbound cefoperazone in rat blood and brain using microdialysis

A sensitive microbore HPLC method was developed for the simultaneous determination of unbound cefoperazone in rat blood and brain using microdialysis. Two microdialysis probes were inserted into the jugular vein/right atrium and brain striatum of Sprague-Dawley rats. Cefoperazone (50 mgkg(-1), i.v.) was then administered via the femoral vein. Blood and brain dialysates were collected and eluted with a mobile phase containing methanol-100 mM monosodium phosphoric acid (30:70, v/v, pH 5.5). The wavelength of the UV detector was set at 254 nm. The detection limit of cefoperazone was 20 ng mL(-1). Isocratic separation of cefoperazone was achieved within 10 min. The intra- and inter-assay accuracy and precision of the analyses were < or =10% in the range of 0.05-10 microg mL(-1). The ratio of the area under the concentration curve of cefoperazone in rat brain and blood was estimated to be about 7-8%. It is concluded that cefoperazone is capable of penetrating the blood-brain barrier.

Frequency stabilization of a frequency-doubled 1556-nm source to the 5S(1/2) ? 5D (5/2) two-photon transitions of rubidium

Improvements in the power level of sources near 1550 nm and in the efficiency of waveguide frequency doublers enabled us to lock a frequency-doubled source directly to the 5S(1/2) ? 5D(5/2) two-photon transitions near 778 nm. We obtained a sufficiently powerful second-harmonic signal, exceeding 2 mW, by doubling an external-cavity diode laser that was amplified by an erbium-doped fiber amplifier in a periodically poled LiNbO(3) channel waveguide. Our experimental scheme can be used for realizing compact, high-performance frequency standards near 1550 nm for fiber-optic communication and sensing applications.

Drug utilization pattern of antiepileptic drugs and traditional Chinese medicines in a general hospital in Taiwan - a pharmaco-epidemiologic study

OBJECTIVE

Studies on antiepileptic drug utilization are important for the optimization of drug therapy and drug control. The present study was to evaluate the drug utilization pattern of standard antiepileptic drugs and traditional Chinese medicines (TCMs) in the treatment of different types of epilepsy in a general hospital in Taiwan.

METHOD

The epileptic patients under antiepileptic drug treatment at Veterans General Hospital-Taipei were considered in the analysis. Current diagnosis was obtained by the neurologist in charge of the patient. All patients were interviewed by standard questionnaire designed to provide specific information on the types of antiepileptic drugs and details of their use. The questionnaire also sought to determine whether TCMs were used, and whether patients were using TCMs in combination with hospital standard treatment. The results were analysed by descriptive statistics.

RESULTS

729 patients with epilepsy definitely diagnosed were analysed in the study. 445 patients (61.04%) were prescribed with one antiepileptic drug. Combinations of two antiepileptic drugs were prescribed to 261 patients (35.80%), and combinations of three or more antiepileptic drugs to 23 patients (3.16%). A total of 1039 antiepileptic drugs was prescribed, corresponding to an average 1.42 drugs per patient. The most frequently prescribed antiepileptic drug was carbamazepine (56.93%), followed by phenytoin (31.96%), valproate (30.73%) and clonazepam (14.13%). Among the 729 epileptic patients, 83.68% used standard antiepileptic drugs alone, 16.32% used antiepileptic drugs in combination with TCMs.

CONCLUSION

Monotherapy is the type of therapy most frequently used in all types of seizures. The selection of antiepileptic drugs is based on efficacy for specific seizure types and epileptic syndromes. The most frequently prescribed antiepileptic drug was carbamazepine, followed by phenytoin, valproate and clonazepam. As some of the patients used TCMs for treatment of epilepsy even when scientific medicine has been provided, further studies on the possible interactions between TCMs and antiepileptic drugs are in progress.

Renal allograft dysfunction associated with rifampin-tacrolimus interaction

OBJECTIVE

To report an interaction between tacrolimus and rifampin with subsequent adverse effects on renal allograft function.

CASE SUMMARY

A 61-year-old Chinese man received a cadaveric renal transplant in 1991. Progressive deterioration of allograft function developed during the following six years while the patient was receiving cyclosporine and prednisolone. In January 1998, tacrolimus was substituted for cyclosporine for late biopsy-proven graft rejection, with target trough blood concentrations between 5 and 8 ng/mL. After conversion, serum creatinine fell to 2.0 mg/dL; the nadir was reached within one year. At the same time, rifampin was instituted for controlling tuberculosis and empiric fluconazole was discontinued. Twelve days later, the patient's serum creatinine concentration rose to 2.9 mg/dL and tacrolimus concentration fell to 1.5 ng/mL, along with oliguria. These findings suggested acute rejection, which was successfully reversed by steroid therapy. However, more than a tenfold increase in the tacrolimus dosage was required to maintain the same concentrations during subsequent months, accompanied by an increase in serum creatinine (from 2.0 to 2.6 mg/dL) and decrease in urine excretion. Biopsy at this time demonstrated acute rejection (Banff I), chronic allograft nephropathy (Banff II), and suspected tacrolimus nephrotoxicity. After unsuccessful methylprednisolone recycling, mycophenolate mofetil was introduced to control rejection and facilitate reduction of the tacrolimus dosage to minimize its nephrotoxicity.

CONCLUSIONS

As a potent CYP3A4 isoenzyme inducer, rifampin coadministration caused the abrupt decrease in tacroiimus blood concentrations, leading to an approximate tenfold increase in its daily dose, which may be important to subsequent allograft dysfunctions.

Pharmacokinetic study of paeoniflorin in mice after oral administration of Paeoniae radix extract

Quantification of paeoniflorin, the principal bioactive component of Paeoniae radix, in mice plasma following oral administration of Paeoniae radix extract was achieved by using a simple and rapid high-performance liquid chromatographic method. The calibration curve for paeoniflorin was linear (r2 = 0.998) over the concentration range 10-200 ng/ml. The coefficients of variation of intra- and inter-day assays were 15.04, 7.31, 6.14, 6.55, 6.63% and 12.71, 6.07, 3.61, 5.51, 4.52% at concentrations of 10, 60, 100, 160, 200 ng/ml, respectively. The recoveries of paeoniflorin from mice plasma were found to be 74.49, 76.83, 80.38 and 80.56% for concentrations of 30, 80, 120 and 160 ng/ml, respectively. The plasma concentration-time curves were fitted with mean terminal half-lives (t(1/2)) of 94.16 min.

Nonlinear directional coupler in periodically poled lithium niobate

Nonlinear wave propagation was investigated experimentally in coupled waveguides by means of the cascaded nonlinearity in quasi-phase-matched second-harmonic generation. With a specially designed wave-vector-mismatch distribution along the propagation axis, cascading was optimized for low fundamental depletion. High-contrast, ultrafast all-optical switching with switching powers of tens of watts was observed.

Multiple-channel wavelength conversion by use of engineered quasi-phase-matching structures in LiNbO(3) waveguides

We report difference frequency generation-based wavelength converters with multiple phase-matching wavelengths that use engineered quasi-phase-matching structures in LiNbO(3) waveguides. Multiple-channel wavelength conversion is demonstrated within the 1.5-mum band and between the 1.3- and 1.5-mum bands. With simultaneous use of M pump wavelengths, these devices can also be used to perform wavelength broadcasting, in which each of N input signals is converted into M output wavelengths.

Purification, characterization and molecular cloning of trichoanguin, a novel type I ribosome-inactivating protein from the seeds of Trichosanthes anguina

The seeds of the plant Trichosanthes anguina contain a type I ribosome-inactivating protein (RIP), designated trichoanguin, which was purified to apparent homogeneity by the combined use of ion-exchange chromatographies, i.e. first with DE-52 cellulose and then with CM-52 cellulose. The protein was found to be a glycoprotein with a molecular mass of 35 kDa and a pI of 9.1. It strongly inhibits the protein synthesis of rabbit reticulocyte lysate, with an IC50 of 0.08 nM, but only weakly that of HeLa cells, with an IC50 of 6 microM. Trichoanguin cleaves at the A4324 site of rat 28 S rRNA by its N-glycosidase activity. The cDNA of trichoanguin consists of 1039 nt and encodes an open reading frame coding for a polypeptide of 294 amino acid residues. The first 19 residues of this polypeptide encode a signal peptide sequence and the last 30 residues comprise an extension at its C-terminus. There are four potential glycosylation sites, located at Asn-51, Asn-65, Asn-201 and Asn-226. A comparison of the amino acid sequence of trichoanguin with those of RIPs such as trichosanthin, alpha-momorcharin, ricin A-chain and abrin A-chain reveals 55%, 48%, 36% and 34% identity respectively. Molecular homology modelling of trichoanguin indicates that its tertiary structure closely resembles those of trichosanthin and alpha-momorcharin. The large structural similarities might account for their common biological effects such as an abortifacient, an anti-tumour agent and anti-HIV-1 activities. Trichoanguin contains two cysteine residues, Cys-32 and Cys-155, with the former being likely to be located on the protein surface, which is directly amenable for conjugation with antibodies to form immunoconjugates. It is therefore conceivable that trichoanguin might be a better type I RIP than any other so far examined for the preparation of immunotoxins, with a great potential for application as an effective chemotherapeutic agent for the treatment of cancer.

Chirped-pulse-amplification circuits for fiber amplifiers, based on chirped-period quasi-phase-matching gratings

A new type of compact chirped-pulse-amplification circuit for high-power amplification of femtosecond pulses in an optical fiber is demonstrated. This circuit is based on a novel pulse compressor, chirped-period quasi-phase-matching gratings in electric-field-poled lithium niobate. The main advantages of this circuit are simplicity, the small number of components, compactness, and wavelength conversion of Er-doped fiber output to the technologically important 780-nm wavelength region.

1.5-microm-band wavelength conversion based on difference-frequency generation in LiNbO3 waveguides with integrated coupling structures

We report wavelength conversion within the 1.5-mum telecommunications band based on difference-frequency generation in periodically poled lithium niobate waveguides with integrated coupling structures. A conversion efficiency of -7 dB and a normalized efficiency of 260%/W are demonstrated. Static tests show that the conversion bandwidth is 72 nm and the conversion efficiency is constant over the 20-dB range of input powers tested.

Involvement of oxidative stress in motorcycle exhaust particle-induced DNA damage and inhibition of intercellular communication

In this study, we investigated the involvement of reactive oxygen species (ROS) in the motorcycle exhaust particle (MEP)-induced genotoxic and non-genotoxic activity in mammalian cell systems. Initially, the capability of MEP to induce ROS was evaluated by using 2',7'-dichlorofluorescin diacetate (DCFH-DA) to detect hydrogen peroxide (H2O2). A five-fold increase in H2O2 was observed in Chinese hamster lung V79 and human lung carcinoma Calu-1 cells treated with 100 microg/ml MEP for 2 h. Under the same experimental conditions, only a two-fold elevation in H2O2 was detected in hepatic cell systems such as BNL.Cl.2, HepG2, and Hep3B. Treatment of the V79 cells with varying concentrations of MEP caused a dose-dependent increase in sister chromatid exchanges (SCEs), which are effectively inhibited by addition of antioxidants, N-acetyl-l-cysteine (NAC) and ascorbic acid. Furthermore, we determined the oxidized bases in the V79 cells after exposure to MEP. The result showed that 500 microg/ml MEP induced a 3.7-fold increase in thymine glycol (TG) and a seven-fold increase in 8-hydroxy-guanosine (8-OHGua) as compared to untreated cells. We subsequently examined whether MEP would affect gap junctional intercellular communication (GJIC), a tumor promotion process, in V79 cells. We found that MEP inhibited GJIC in a dose-response fashion. Maximal inhibition occurred at 500 microg/ml. The concentration that inhibited at 0.5 of the fraction of the control was 200 microg/ml. Interestingly, when cells were pretreated with NAC or ascorbic acid, they could abolish the MEP-mediated inhibition of GJIC. In addition, a moderate decrease of glutathione was observed in the V79 cells during exposure to MEP. Taken together, our findings suggest that MEP can induce oxidative stress in a broad range of cell lines, especially in lung cell systems. The MEP-induced oxidative stress was critically involved in both genotoxic and non-genotoxic activity.

Engineerable compression of ultrashort pulses by use of second-harmonic generation in chirped-period-poled lithium niobate

We demonstrate the use of an aperiodic quasi-phase-matching (QPM) grating to generate second-harmonic pulses that are stretched or compressed relative to input pulses at the fundamental frequency. We frequency doubled an externally chirped erbium-doped fiber laser generating 17-ps (FWHM) pulses at 1560nm to produce near-transform-limited 110-fs (FWHM) pulses at 780nm by use of a 5-cm-long lithium niobate crystal poled with a QPM grating chirped from an 18.2- to a 19.8-microm period.

Medication use characteristics in an ambulatory elderly population in Taiwan

OBJECTIVE

To compare prescribing patterns between the elderly and nonelderly in 1994, to disclose prescribing trends in the elderly-between 1992 and 1994, to explore whether drug utilization is in agreement with disease prevalence, and to identify suboptimal prescribing by drug category for ambulatory elderly patients.

DESIGN

Cross-sectional survey at two separate time intervals.

SETTING

All public group practice centers (GPCs) in Taiwan.

PATIENTS

Ambulatory adults who visited GPCs during 1 random week. Those 65 years or over were classified as the elderly group, and those 20-64 years were the nonelderly group.

MAIN OUTCOME MEASURES

Mean diagnosis, drug use, and expenditure; frequency of diagnosis; and prescribing by therapeutic category.

RESULTS

Data on 30777 elderly and 38184 nonelderly patients were collected in 1994. There was widespread use of antacids. Compared with nonelderly adults, the elderly were diagnosed with more diseases (1.3 vs. 1.2, respectively; p < 0.01), received more medications (4.7 vs. 4.1, respectively; p < 0.01), and had higher drug expenditures (5.4 vs. 4.6, respectively; p < 0.01). Chronic illness was more prevalent in the elderly, which accounted for the extensive use of cardiovascular drugs (32.1%), nonsteroidal antiinflammatory drugs (25.9%), and anxiolytics (15.9%). The upward trend in the elderly from 1992 to 1994 with hypertension (18.6% vs. 20.0%) or diabetes (9.2% vs. 10.9%) did not result in more cases of cerebrovascular disease (7.1% vs. 4.9%). There was a substantial increase in use of antispasmodic and gastroprokinetic agents (4.5% to 10.7%); the use of antacids decreased (73.6% to 63.4%) in the elderly.

CONCLUSIONS

Compared with the prevalence of disease, there was extensive nonspecific use of anxiolytics and antacids. However, lessened use of antidepressants and postmenopausal hormone replacement may have an impact on morbidity and mortality and deserves particular attention.

Adiabatically tapered periodic segmentation of channel waveguides for mode-size transformation and fundamental mode excitation

We report modeling, fabrication, and characterization of tapered waveguides, using periodically segmented annealed proton exchange in LiNbO(3). For a taper transforming the 1/e full width (intensity) mode size from 6.0 microm x 4.4 microm to 2.0 microm x 1.3 microm, 0.4-dB excess loss was observed. The large, slightly elliptical mode can ease coupling to single-mode fibers and circular free-space beams. The same taper structure was used to excite a highly multimoded (13 modes) waveguide with more than 95% of the power stably launched into the lowest-order mode. This function is useful for nonlinear waveguide devices, such as difference-frequency generators, in which modes at highly disparate wavelengths interact.