3'-5' Exonucleolytic activity of DNA polymerases: structural features that allow kinetic discrimination between ribo- and deoxyribonucleotide residues

We have determined rates for the excision of nucleotides from the 3' termini of chimeric DNA-RNA oligonucleotides using the Klenow fragment (KF) and two other DNA polymerases, from phages T4 and T7. For these studies, we synthesized DNA-RNA chimeric oligonucleotides with RNA residues in defined positions. When a ribonucleotide residue was placed at the 3' terminus, all three DNA polymerases removed it at the same rate as they did for substrates composed solely of deoxynucleotide residues. There was a decrease in the excision rate, however, when a ribonucleotide residue was located at the second or third position from the 3' terminus. When both the second and third positions were occupied by ribonucleotide residues, the excision rate for the 3' terminal nucleotide was reduced even further and was almost identical to the rate observed when the DNA polymerases encountered single-stranded RNA. The magnitude of the effect of ribonucleotide residues on the excision rate was lower when Mn(2+) replaced Mg(2+) as the essential divalent cation. Two KF mutations, Y423A and N420A, selectively affected the excision rates for the chimeric substrates. Specifically, Y423A totally abolished the rate reduction when there was a single ribonucleotide residue immediately preceding the 3' terminus, whereas N420A diminished, but did not eliminate, the rate reduction relative to that of wild-type KF when the single ribonucleotide residue occupied either the second or third position from the 3' terminus. These results are consistent with the structure of a KF-ss DNA complex from which it can be deduced, by modeling, that a 2' OH group on the second sugar from the 3' terminus would sterically clash with the Tyr 423 side chain, and a 2' OH group on the third sugar would clash with the side chain of Asn 420. The corresponding mutations in T4 DNA polymerase did not affect the rate of hydrolysis of the chimeric oligonucleotides. Thus, there appears to be a major difference in the kinetic behavior of KF and T4 DNA polymerase with respect to the exonuclease reaction. These results are discussed with respect to their possible biological relevance to DNA replication.

Polarization-resolved output analysis of X-ray multiple-wave interaction

The polarization suppression of the interfering components in X-ray multiple-wave interaction is observed for the first time by using a polarization analyzer with an arbitrary inclination of the diffraction plane with respect to that of the investigated crystal. The condition for total suppression of the multiple-wave interaction outside the investigated crystals by a polarization analyzer is derived theoretically from the modified Born approximation. By means of the partial suppression of the strong interfering component, the increase in the visibility of multiple-wave interference is experimentally and theoretically demonstrated. The proposed experimental polarization-resolved technique provides an operational way to enhance the visibility of X-ray multiple-wave interaction outside the investigated crystals for direct phase determination.

Carcinoembryonic antigen in monitoring of response to systemic chemotherapy in patients with metastatic colorectal cancer

The response to chemotherapy of solid tumors is generally assessed by measuring tumors visualized by imaging. However, the response assessment based on imaging is not always feasible because patients often have disease not measurable by imaging, such as diffuse peritoneal dissemination. We evaluated the correlation between the change on imaging and change in CEA levels for assessing chemotherapeutic response of patients with metastatic colorectal cancer. Between July 1993 and August 1999 we retrospectively examined 136 patients with metastatic colorectal carcinoma, all of whom had measurable lesions. Forty patients received oral tegafur-uracil (300 mg/m2/day) plus folinic acid (60 mg/day) for 4 weeks, repeated every 5 weeks, as the firstline treatment. Another 96 patients received either a weekly intravenous bolus injection of 5-fluorouracil (400 mg/m2) plus folinic acid (20 mg/m2), or an intravenous bolus injection of 5-fluorouracil (425 mg/m2) plus folinic acid (20 mg/m2) for 5 consecutive days every month. Responders, based on CEA assessment, were defined as those with a greater than 50% drop in CEA level for more than 4 weeks. The pretreatment CEA levels were elevated beyond the normal cutoff value in 110 (81%) patients. A response rate of 18.4% (95% CI, 11.9-24.9%), including 8 complete remissions and 17 partial remissions, was achieved according to imaging studies. The response rate assessed by CEA was 25% (34/136). Sixteen responders (47%) based on CEA had no remission on imaging. The sensitivity of change in CEA levels in the prediction of true responders and progressive diseases on imaging were 72% and 81%, respectively. In terms of the positive predictive value, change in CEA levels in the prediction of true responders and progressive disease on imaging were 53% and 85%, respectively. Patients with remarkable falls on CEA levels survived significantly longer than nonresponders (P < 0.001, log-rank test). At follow-up of 48 months the median survival for responders and nonresponders assessed by CEA was 28 months and 13 months, respectively. These data suggest that measurement of CEA levels might be helpful in monitoring chemotherapeutic response when imaging study is unsuitable for assessing the response in clinical practice. Furthermore, measurement of CEA levels may be helpful in determining the prognosis of patients with metastatic colorectal cancer receiving chemotherapy.

Antimicrobial activity of tannin components from Vaccinium vitis-idaea L

Reactive oxygen species have been implicated as important pathological mediators in many clinical disorders, including periodontal disease. As a possible alternative for the treatment of periodontal disease, the antimicrobial activity of six tannins isolated from Vaccinium vitis-idaea L., with confirmed antioxidant activity, were assayed by the agar dilution method against selected periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. The results showed that epicatechin-(4beta-->8)-epicatechin-(4beta-->8, 2beta-->O-->7)-catechin had strong antimicrobial activity against P. gingivalis and P. intermedia, but not A. actinomycetemcomitans. The other tannins tested did not show antimicrobial activity. We conclude that tannins isolated from V. vitis-idaea L. with antimicrobial activity could potentially be used for the treatment of periodontal disease.

Quantitative feedback synthesis of sampled-data systems with time-delay by approximate Z-transform

In this paper, the equivalent disturbance rejection (EDR) in QFT design methodology is proposed for dealing with sampled-data systems with time-delay. This EDR is mainly to overcome the non-minimum phase zero generated by the first order Pade' approximation of the time-delay factor. Due to plant parameter uncertainty, the analogue controller is to be designed so that the system response lies within permissible bounds. By approximate Z-transform, the analogue controller can be transformed directly into a digital one and then the analogue plant is transformed into the digital plant, with sampling time as a free parameter. By adjusting the sampling time, the uncertain sampled-data system can be stabilized. In comparison with other approaches, our design framework is much more systematic by using only algebraic manipulations and transparent enough to guide the designer to realize the physical controller for the plant with prescribed bounds on its parameters.

Antioxidant and hepatoprotective effects of punicalagin and punicalin on acetaminophen-induced liver damage in rats

Punicalagin and punicalin were isolated from the leaves of Terminalia catappa L., a Combretaceous plant distributed throughout tropical and subtropical beaches, which is used for the treatment of dermatitis and hepatitis. Our previous studies showed that both of these compounds exert antioxidative activity. In this study, the antihepatotoxic activity of punicalagin and punicalin on acetaminophen-induced toxicity in the rat liver was evaluated. After evaluating the changes of several biochemical functions in serum, the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were increased by acetaminophen administration and reduced by punicalagin and punicalin. Histological changes around the hepatic central vein and oxidative damage induced by acetaminophen were also recovered by both compounds. The data show that both punicalagin and punicalin exert antihepatotoxic activity, but treatment with larger doses enhanced liver damage. These results suggest that even if punicalagin and punicalin have antioxidant activity at small doses, treatment with larger doses will possibly induce some cell toxicities.

Antioxidant and free radical scavenging effects of the tannins of Terminalia catappa L

Reactive oxygen species (ROS) react with biological molecules and destroy the structure of cells and eventually cause free radical-induced disease such as inflammation and cancer. Previous studies showed that an aqueus extract of Terminalia catappa L. exhibited superoxide radical scavenger activity and modification of mitomycin C-induced clasto-genicity. In order to investigate the multiple antioxidant effect of the tannin components of T. catappa L., their ability to prevent lipid peroxidation, superoxide formation and their free radical scavenging activity were evaluated. The results indicated that all of these components showed potent antioxidant activity. Punicalagin and punicalin were the most abundant components and had the strongest anti-oxidative effects of this group of tannins.

Randomized trial comparing weekly bolus 5-fluorouracil plus leucovorin versus monthly 5-day 5-fluorouracil plus leucovorin in metastatic colorectal cancer

BACKGROUND/AIMS

The purpose of this study was to compare the efficacy and toxicity profiles of weekly intravenous (i.v.) bolus injection of 5-fluorouracil plus low-dose leucovorin with the Mayo Clinics' monthly 5-day schedule of 5-fluorouracil and leucovorin in the treatment of metastatic colorectal cancer.

METHODOLOGY

A total of 96 patients with previously untreated metastatic colorectal cancer were randomized to receive either a weekly i.v. bolus injection of 5-fluorouracil 400 mg/m2 plus leucovorin 20 mg/m2 (weekly arm), or i.v. bolus injection of 5-fluorouracil 425 mg/m2 plus leucovorin 20 mg/m2 for 5 consecutive days every 4 or 5 weeks (monthly arm). Therapy was continued until disease progression or unacceptable toxicity appeared. In the presence of disease progression, the study regimen was stopped and second-line treatment was instituted after the patient was discontinued from this study.

RESULTS

There was no significant difference of response rates between both regimens. The response rate were 14.3% in the weekly arm (2 CR and 5 PR, 95% CI: 2.6-25.2%) and 10.6% in the monthly arm (1 CR and 4 PR; 95% CI: 6.5-32.3%), respectively (P = 0.8957). The survival times were also similar between the two (P = 0.4207, log-rank test). The median survival were 15.8 months in the monthly arm and 18.4 months in the weekly arm. Hematologic toxicity was minimal in both arms. However, the monthly arm produced a higher toxicity in severe (grade 3-4) diarrhea (14.9% vs. 2%; P = 0.029) and stomatitis (8.5% vs. 0; P = 0.054).

CONCLUSIONS

Weekly bolus injection of 5-fluorouracil and low-dose leucovorin achieved a similar response rate and survival as compared with the Mayo Clinics' monthly 5-day schedule, but severe toxicity was less commonly seen using the weekly regimen. As current chemotherapeutic treatment for metastatic colorectal cancer is largely palliative rather than curative, the weekly bolus regimen may be a more favorable approach in managing metastatic colorectal cancer.

Phase II study of oral tegafur-uracil and folinic acid as first-line therapy for metastatic colorectal cancer: Taiwan experience

BACKGROUND

Tegafur-uracil has become an important regimen in the treatment of metastatic colorectal cancer. Tegafur is a prodrug that is converted to 5-fluorouracil (5-FU) and has been reported to be less toxic and to have a higher therapeutic index. The additional advantage of tegafur is oral administration, an important consideration to improve the quality of life in these patients. Tegafur in combination with uracil is thought to have greater anti-tumor activity due to the inhibitory effect of uracil on the degradation of 5-FU by hepatic dihydropyrimidine dehydrogenase. Tegafur with folinic acid has been reported with modest efficacy and acceptable toxicity. The purpose of this study was to evaluate the effectiveness and toxicity profile of oral tegafur-uracil plus folinic acid in Chinese patients with metastatic colorectal cancer.

METHODS

Between May 1998 and August 1999, 40 patients with metastatic colorectal carcinoma were enrolled in this study. All the patients had to have measurable lesions. The initial dose of tegafur-uracil was 300 mg/m2/day for 28 days, followed by a 7-day rest period. Folinic acid was administered orally at a dose of 60 mg/day concurrently with tegafur-uracil. For patients with neutrophil count <1500/microl or a platelet count <100,000/microl after treatment, the treatment was postponed for a maximum of 2 weeks. After that time, if the neutrophil count was 1000-1500/microl and the platelet count was 70,000-100,000 microl, the dose of tegafur-uracil was reduced by 50%, and if lower values resulted, the treatment was discontinued.

RESULTS

Forty patients received a total of 318 courses of treatment and a response rate of 32.5% (95% CI, 18-47%), including five complete remissions and eight partial remissions, was achieved. Toxicity was mild and generally tolerable. Gastrointestinal toxicities, including diarrhea, nausea and vomiting, were the major side effects. Seven incidences (17.5%) of grade 3-4 gastrointestinal toxicity were observed. Hematological toxicities were minimal with no evidence of severe (grade 3 or 4) leukopenia and thrombocytopenia. No episode of hepatic, renal, cardiac or neurological toxicity occurred. Two patients (5%) developed transient painful fissuring erythroderma over their palms and soles (the hand-foot syndrome).

CONCLUSIONS

The data from our study indicate that oral tegafur-uracil plus folinic acid is an active and tolerable first-line treatment for Chinese patients with metastatic colorectal cancer, with the additional advantage of being easily administered at home.

Factors predictive of survival in patients with node-positive colorectal cancer in Taiwan

BACKGROUND/AIMS

Preoperative CEA levels, depth of tumor penetration, and the number of positive lymph nodes were reported as independent factors prognostic of survival in colorectal cancer patients. This study was carried out in an effort to evaluate the prognostic significance of these three factors in patients with Dukes' C colorectal cancer in Taiwan.

METHODOLOGY

Between 1992 and 1994, a total of 112 patients with node-positive colorectal cancer were evaluated retrospectively at the Veteran General Hospital-Taipei. All patients underwent potentially curative surgery and received 5-fluorouracil based adjuvant chemotherapy. Reference to the Dukes' classification was according to the classical criteria described in 1932 for carcinoma of the rectum and adapted for use in colonic tumors. Data on the location of the tumor, depth of penetration, number of positive lymph nodes, degree of tumor differentiation, and preoperative CEA levels were analyzed to understand their association with survival. Blood samples for CEA measurement were taken a few days before operation. A multivariate analysis using the Cox's proportional hazards regression model was then performed to determine the most important independent predictors of survival among all the possible variables.

RESULTS

Using univariate analysis the number of positive lymph nodes (P < 0.001), penetration of the bowel wall (P < 0.001), and preoperative CEA levels (P < 0.001) were found as significant prognostic factors, while the degree of tumor differentiation, location of the tumor, age and sex were not significant. Using multivariate Cox analysis the number of positive lymph nodes, penetration of the bowel wall, and preoperative CEA levels were still found as independent prognostic factors in node-positive colorectal cancer patients.

CONCLUSIONS

Data obtained from our study indicates that preoperative CEA levels, depth of tumor penetration, and the number of positive lymph nodes were independent prognostic factors in Dukes' C colorectal cancer patients. They could serve as appropriate modifications of the initial Dukes scheme in node-positive diseases.

Intra-articular ketamine for pain control following arthroscopic knee surgery

BACKGROUND

In an attempt to demonstrate the peripheral effect of ketamine on the synovia of knee joint and to smoothen the recovery from arthroscopic knee surgery, this study was designed to evaluate the analgesic effect of intra-articular ketamine injection after knee arthroscopy.

METHODS

In a double blind randomized study, 60 patients were assigned to three groups. Group A patients received saline 5 mL intra-articularly after closure of the surgical wound to serve as control; group B patients received ketamine 0.5 mg/kg of body weight intra-muscularly to rule out the systemic effect and group C patients received ketamine 0.5 mg/kg of body weight diluted with saline up to 5 mL intra-articularly. After surgery, patients were evaluated for pain with visual analogue scale (VAS 0 to 10) for 24 h with the operated leg in the position of extension rest and active flexion of the knee joint to 60 degree angle. Rescue pethidine (1 mg/kg of body weight) was given intra-muscularly for pain relief at request every 4 h postoperatively if necessary. The time to first rescue analgesic request was recorded, and the total doses of pethidine were calculated.

RESULTS

The results showed no difference in the VAS pain scores at rest and during active motion in the range of 60 degree among three groups during a 24 h observation.

CONCLUSIONS

Ketamine had been reported to have peripheral analgesic effects with variable duration on measurements of pain and hyperalgesia. However, in the present study, we failed to demonstrate that ketamine could provide a clinically relevant peripheral analgesic effect for postoperative arthroscopic pain.

Endoscopic placement of Sengstaken-Blakemore tube

A Sengstaken-Blakemore (SB) tube, when used approximately, still has a place in the management of acute variceal bleeding. Due to a number of reported complications from the misplacement of this tube, an x-ray localization before full inflation of the gastric balloon is recommended as the standard of care. Here, we report a new technique of SB tube placement with endoscopic confirmation in three patients. This technique is easy, accurate, and can be performed in any unit where a patient with variceal bleeding can be managed. Because it cuts down on the need for an x-ray or ultrasound confirmation, this technique may well become the "standard of care" among the practicing gastroenterologists.

Discovery of a potent, non-triketone type inhibitor of 4-hydroxyphenylpyruvate dioxygenase

3-Cyclopropanecarbonyloxy-2-cyclohexen-1-one has been found to be a new, potent, low molecular weight non-triketone type inhibitor of 4-hydroxyphenylpyruvate dioxygenase with IC50 value of 30 nM. Preliminary studies suggest that the two carbonyl groups present in the compound are crucial for the inhibition activity.

Convulsions during superior laryngeal nerve block--a case report

Complications following local anesthesia for fiberoscope-assisted intubation are rare. We report a case with surgical condition indicating awake endotracheal intubation for general anesthesia, suffering from convulsions after receiving left superior laryngeal nerve block to facilitate the procedure. The possible cause may be accidental injection of the local anesthetic into the vertebral artery. Although the amount of local anesthetic injected was small, its concentration in the brain might be high enough to cause convulsion. The central nervous system toxicity of local anesthetic depends not only on the dosage used, but also on the rate of injection, as well as the site at which it is injected. Starting from a small dose together with careful monitoring of patient's response is advised when nerve block in the neck is performed. Here, we also emphasize the importance of availability of resuscitation equipment for maintaining adequate ventilation and circulation in case of emergency.

Folk medicine Terminalia catappa and its major tannin component, punicalagin, are effective against bleomycin-induced genotoxicity in Chinese hamster ovary cells

Terminalia catappa L. is a popular folk medicine for preventing hepatoma and treating hepatitis in Taiwan. In this paper, we examined the protective effects of T. catappa leaf water extract (TCE) and its major tannin component, punicalagin, on bleomycin-induced genotoxicity in cultured Chinese hamster ovary cells. Pre-treatment with TCE or punicalagin prevented bleomycin-induced hgprt gene mutations and DNA strand breaks. TCE and punicalagin suppressed the generation of bleomycin-induced intracellular free radicals, identified as superoxides and hydrogen peroxides. The effectiveness of TCE and punicalagin against bleomycin-induced genotoxicity could be, at least in part, due to their antioxidative potentials.

Atrial tachyarrhythmias induced by acetylcholine in tilapia (Oreochromis sp.) isolated atria

1. Effects of the parasympathetic neuromediator acetylcholine (ACh) on atrial tissues vary greatly depending on the species, the type of atrial cells and experimental conditions. The aim of the present study was to investigate, with microelectrode techniques, the arrhythmogenic effects of ACh in tilapia (Oreochromis sp.) isolated atria at room (22-25 degrees C) and high temperature (37 degrees C). 2. Acetylcholine (1-10 micromol/L) shortened action potential duration (APD), depressed action potential plateau and decreased twitch force in tilapia atria, as it did in human atrial fibres. In addition, ACh induced premature responses and re-entrant tachyarrhythmias (TA; frequency range from 7 to 25 Hz) in five of 19 and 14 of 22 tilapia atria tested at room and high temperature, respectively. The higher incidence of ACh-induced TA at 37 degrees C compared with room temperature was statistically significant. 3. The ACh-induced TA consisted of high-frequency and uniform action potentials accompanied by tension oscillation and elevation of diastolic force (flutter). Acetylcholine-induced TA could be readily abolished by atropine (1 micromol/L) and prevented by treatment with agents with local anaesthetic properties, such as 0.1 micromol/L tetrodotoxin or 3 micromol/L quinidine. The antagonistic action of quinidine occurred without significant prolongation of APD. 4. The present findings suggest that pharmacological concentrations of the cholinergic muscarinic agonist ACh readily induce TA (mainly atrial flutter) in tilapia atria, presumably via sodium channel-dependent re-entrant excitation. The poikilothermic tilapia appears to be an appropriate animal model for the study of atrial TA.

Effect of methanol-containing additive on the emission of carbonyl compounds from a heavy-duty diesel engine

This study was aimed at determining the effect of methanol-containing additive (MCA) on the emission of carbonyl compounds (CBCs) generated from the diesel engine. For this experiment, a heavy-duty diesel engine was connected with a full flow critical flow ventri (CFV) type dilution tunnel, a Schenck GS-350 DC dynamometer, and a DC-IV control system in series. The operating conditions of the heavy-duty diesel engine for both cold-start and hot-start Transient Cycle tests and for both low-load and high-load steady-state tests were ascertained. The exhaust of CBCs collected from a 2,4-dinitrophenylhydrazine (2,4-DNPH)-coated cartridge were first converted to corresponding hydrazone derivatives, which were then solvent-eluted and analyzed by a High Performance Liquid Chromatograph (HPLC) with an ultraviolet-visible (UV) detector. When either 10% or 15% MCA was used, the emission factors of the CBCs acrolein and isovaleraldehyde increased by at least 91%. Accordingly, future studies must be done to cut down the emission of CBCs when MCA and methanol alternative fuels are used.

Postoperative intramuscular dextromethorphan injection provides pain relief and decreases opioid requirement after modified radical mastectomy

BACKGROUND

Narcotics are still the therapeutic mainstay for postoperative pain relief. However, many unwanted side effects are accompanied. NMDA antagonists have been demonstrated to produce analgesic and antihyperalgesic effects, moreover, to possess potentiated effect of narcotics on postoperative pain management.

AIMS

To examine whether postoperative dextromethorphan (DM), an antitussive and also an NMDA antagonist, intramuscular injection (I.M.) reduced pain and analgesic requirement after modified radical mastectomy (MRM).

METHODS

Sixty-one patients scheduled for MRM were included and randomly allocated into two groups. For the control group (n=31), patients received chlorpheniramine maleate (CPM, 20 mg) I.M., while in the DM group (n = 30), 40 mg DM containing 20 mg CPM (I.M.) was given at the end of surgery. Meperidine (1 mg/kg, I.M.) was prescribed for postoperative pain relief, if ask. The time to first meperidine injection, total meperidine consumption, worst pain score, bed-rest time, and meperidine-related side effects were recorded for 48 hours postoperation.

RESULTS

A longer time to first meperidine injection (20.3 +/- 1.4 vs 1.5 +/- 0.2 hr, p < 0.001) and lower meperidine consumption (10.7 +/- 4.0 vs 70.7 +/- 8.9 mg, p < 0.001) were observed in the DM group than the control group. The average bed rest time was significantly shorter in the DM group than in the control group (18.9 +/- 1.5 vs 23.4 +/- 1.6 hr, p < 0.001). The number of patients who required meperidine injection (6 vs 27, p < 0.005) and meperidine-related side effects were significantly lower in the DM group than in the control group (1 vs 7, p < 0.025). No difference was noted in worst VAS pain score between the DM and the study groups.

CONCLUSION

Postoperative DM I.M. injection provided an analgesic effect and reduced meperidine requirement after MRM.

Preoperative carcinoembryonic antigen level as an independent prognostic factor in colorectal cancer: Taiwan experience

BACKGROUND

Preoperative carcinoembryonic antigen (CEA) level is considered as a factor predictive of survival in colorectal cancer patients. Patients with normal (<5 ng/ml) or lower preoperative CEA levels were reported to have significantly longer survival. This study was carried out in an effort to evaluate the prognostic significance of preoperative CEA levels of patients with colorectal cancer in Taiwan.

METHODS

Between 1990 and 1994, 218 patients with histologically confirmed colorectal cancers were evaluated retrospectively at the Veterans General Hospital-Taipei. All the patients had undergone potentially curative surgery. Patients with metastatic diseases were not included. 5-Fluorouracil-based adjuvant chemotherapy was administered if the patients had Dukes' C disease. Reference to the Dukes' classification was according to the classical criteria described in 1932 for carcinoma of the rectum and adapted for use in colonic tumors. Data on gender, age, degree of tumor differentiation, location of the tumor, tumor size, lymph node metastasis, penetration of the bowel wall and preoperative CEA levels were analyzed to determine their association with survival. Blood samples for CEA measurement were taken a few days before operation and were analyzed using the radioimmunoassay method. Multivariate analysis by Cox's proportional hazards regression model was performed to determine the most important predictors of survival among all of the possible variables.

RESULTS

By univariate analysis, the size of the tumor (p = 0.012), lymph node metastases (p = 0.007), penetration of the bowel wall (p < 0.001) and preoperative CEA levels (p < 0.001) were found to be significant prognostic factors, while gender, age, degree of tumor differentiation and location of the tumor were not significant. By multivariate Cox analysis, lymph node metastases (p = 0.003), penetration of the bowel wall (p = 0.0001) and preoperative CEA levels (p = 0.0001) were found to be independent prognostic factors in colorectal cancer patients.

CONCLUSIONS

The data from our study indicate that in addition to lymph node metastases and penetration of the bowel wall, the preoperative CEA levels are also an independent prognostic factor in non-metastatic colorectal cancer patients after curative surgery. This could serve as an appropriate modification to the initial Dukes' scheme in colorectal cancer.

Emission characteristics of VOCs from athletic tracks

Dynamic and flow-through flux chambers are convenient tools for field measurements of gas or VOC emission flux from solid surfaces in the field. This study was undertaken to collect on site and quantify the emissions of volatile organic compounds (VOCs) released from athletic running tracks. Three typical types of tracks, one synthetic rubber and two tracks (types I and II) consisting mainly of polyurethane, were studied. They were all installed with adhesives and backings, both of which contributed significant amount of VOCs. VOCs released from the track surface were collected with a flux chamber and subsequently analyzed by a gas chromatograph/mass spectrometer (GC/MS). Also, for each track and at each selected time the emission flux and mass emission were measured on site under outdoor conditions over a period of 40 min. GC/MS analyses show that the VOCs emitted include 2-methyl furan, butanal, methyl ethyl ketone, benzene, heptane, methyl isobutyl ketone, toluene+octane, hexanal, nonane+ethylbenzene, xylenes+styrene, propyl benzene, decane, 1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, 1,2, 3-trimethyl benzene and undecane. Of these, hexanal was the common and principal compound for all three types of tracks. 2-Methyl furan and methyl isobutyl ketone were the characteristic compounds for the synthetic rubber and the type II of polyurethane tracks, respectively. In the field studies, no unique compounds were found in the type I of polyurethane tracks. For each of these three types of tracks the total-VOCs emission flux was correlated to the track age and track surface temperature. The results of multiple regression analysis showed good correlation. The type II polyurethane track had the highest decay rate, while the synthetic rubber track had the lowest decay rate. Two years after the track installation, the VOC concentrations measured at 1.5 m above the track, the breathing height of school children, were not significantly higher than the background levels.

Effects of punicalagin and punicalin on carrageenan-induced inflammation in rats

Punicalagin and punicalin were isolated from the leaves of Terminalia catappa L. In this study, we evaluated the anti-inflammatory activity of punicalagin and punicalin carrageenan-induced hind paw edema in rats. After evaluation of the anti-inflammatory effects, the edema rates were increased by carrageenan administration and reduced by drug treatment. After 4 hr of carrageenan administration, the best effect group was the punicalagin (10 mg/kg) treated group (inhibition rate was 58.15%), and the second was the punicalagin (5 mg/kg)-treated group (inhibition rate was 39.15%). However, even if the anti-inflammatory activity of punicalagin was the same as punicalin at the 5 mg/kg dose, the inhibition effect from larger doses of punicalagin was increased, but there was a decrease with a larger dose of punicalin. The data showed that both punicalagin and punicalin exert anti-inflammatory activity, but treatment with larger doses of punicalin may induce some cell damages.

Postoperative intramuscular dextromethorphan injection provides postoperative pain relief and decreases opioid requirement after hemorrhoidectomy

BACKGROUND

Previous studies have shown that dextromethorphan (DM) produces an analgesic/antihyperalgesic effect. This study was designed to examine whether postoperative DM intramuscular (i.m.) injection could reduce post-hemorrhoidectomy pain.

METHODS

At the end of the surgery, patients in the study group (n = 30) were given an intramuscular injection of 40 mg DM and 20 mg chlorpheniramine (CPM) while in the study group (n = 30), the patients were given intramuscular 20 mg CPM only. Pethidine (1 mg/kg, i.m.) was prescribed for postoperative pain relief if required. The time to first pethidine injection, total pethidine consumption, worst pain score, and pethidine-related side effects were recorded for 48 h postoperatively.

RESULTS

The time from the end of operation to the first pethidine injection was 5.4 +/- 1.6 h and 17.8 +/- 3.7 h (P = 0.006) in the control group and the study group, respectively. Total pethidine consumption was 139.5 +/- 11.5 mg and 77.5 +/- 12.2 mg (P < 0.001) in the control group and the study group, respectively. The worst VAS score was 7.5 +/- 0.2 and 7.1 +/- 0.2 (P = 0.09) in the control and the study groups, respectively. The number of patients who required pethidine injection was 29 and 21 (P < 0.005) in the control and the study groups, respectively. The number of patients who suffered pethidine-related side effects was 7 and 1 (P < 0.025) in the control and the study groups, respectively.

CONCLUSIONS

We found that intramuscular DM given at the end of operation could provide good postoperative pain relief and decrease the pethidine requirement after hemorrhoidectomy.

Risk and patterns of brain metastases in colorectal cancer: 27-year experience

PURPOSE

In patients with colorectal cancer, brain metastasis is infrequent. This study aims to elucidate the risk, pattern of occurrence, and survival time after different treatment modalities.

METHODS

A retrospective review of all patients with colorectal cancer admitted to the Veterans General Hospital-Taipei between 1970 and 1996 from our hospital was performed. Univariate analysis for survival determination was performed.

RESULTS

Brain metastases developed subsequent to surgery for colorectal cancer in 53 well-documented patients, at a median of 36 months after surgery. Brain metastases were more commonly seen in rectal cancer and often occurred concurrently with lung metastases. Forty of these patients received active intervention in terms of surgery, chemotherapy, or radiotherapy, with surgical intervention achieving a significantly increased mean survival time (+/- standard deviation) compared with chemotherapy or radiotherapy or both of 86.6 +/-17.35 vs. 2.9 +/- 0.59 months (P < 0.05).

CONCLUSION

Increased awareness of the possibility of brain metastases, early diagnosis, and aggressive therapy can provide increased survival time for patients with colorectal cancer with brain metastases.

Antioxidant activity of tannin components from Vaccinium vitis-idaea L

Reactive oxygen molecules have been implicated as important pathological mediators in many clinical disorders and periodontal disease. To provide possible alternative treatment of periodontal disease, six tannins isolated from Vaccinium vitis-idaea L. were evaluated for anti-lipid peroxidation, anti-superoxide formation and free radical scavenging activity. The results showed that cinnamtannin B1 displayed the strongest anti-lipid peroxidation activity, proanthocyanidin A-1 displayed the strongest superoxide scavenging activity, and epicatechin-(4beta--> 6)-epicatechin-(4beta-->8, 2beta-->O--> 7)-catechin had the strongest anti-superoxide formation effect. We conclude that tannins isolated from V. vitis-idaea L. exhibited multiple antioxidant activity, and could be used for the treatment of periodontal disease.

Scanning electron microscopy observation of vascularization around hydroxyapatite using vascular corrosion casts

An intimate relationship exists between the regenerative response of the vascular and osseous elements following hydroxyapatite (HA) implantation. In order to fully comprehend the 3-dimensional vascular architecture around HA, dense HA particles were implanted into the tibiae of dogs. Following healing periods of 2 weeks, 1 month, and 3 months, the tibiae were prepared by the corrosion cast technique. Under scanning electron microscopy (SEM) observation, the characteristic vascular morphology of the HA-implanted cavity was successfully demonstrated. The initial vascularization began in the form of loose sinusoidal capillaries. Many sinusoids formed a complex network by anastomosing with each other. The newly formed vessels extended centripetally from the peripheral cavity wall and from the periosteal surface. Under greater magnification, the tapered vascular sprouting was shown to project into the space that was previously occupied by an HA particle. The presence of vascular sprouting is clearly an important indicator of angiogenesis. Increasing vascularization was demonstrated with time. The presence of vessels in the Haversian's canal indicated the more established vascularization. Almost full vascularization of the HA-implanted cavity was seen 3 months after implantation. The vascular organizational layout of the cavity was also clearly shown in the fractured transverse-sectioned sample. In the control without HA implantation, the central region of the cavity showed a hollow pattern in the initial stage. The vascularization looked like it was collapsing and not fully filling the cavity. However, remarkable differences of the final vascular pattern could not be found between the study and control group after 3-month implantation. The study provides the time-lapsed 3-dimensional vascular changes of the HA-implanted cavity, as well as the value of the corrosion cast technique in examining the bony circulation.