Surgical treatment for rectal prolapse

BACKGROUND

The problem of full-thickness rectal prolapse is formidable, with no clear predominant treatment of choice. Several operations have been proposed to correct rectal prolapse which can be divided into transabdominal and perineal procedures.

METHODS

From September 1982 to October 1999, 32 patients with rectal prolapse were treated with surgical procedures. There were 16 males and 16 females with a mean age of 58.3 years (Range 17-89). Forteen patients received rectopexy procedure, 6 patients received sigmoidectomy, 6 patients received perineal rectosigmoidectomy, 1 patient received Delorme procedure, 1 patient received Thiersch procedure and 4 patients received laparoscopic-assisted sigmoidectomy. The median follow up times were 7.5 years.

RESULTS

In the rectopexy group, complication occurred in one patient (7.1%) and one patient recurred (7.1%). In the sigmoidectomy group, there were no complication but one patient recurred (10%). In the perineal rectosigmoidectomy group, there were no complication, but one patient recurred (16.7%). The total complication rate were 3.1% and total recurrence rate were 9.3%.

CONCLUSIONS

Although, the best operation for rectal prolapse remains a controversial subject, we believe that laparoscopic-assisted sigmoidectomy offers a promising new option for the treatment of rectal prolapse.

Phase II study of gemcitabine in patients with advanced hepatocellular carcinoma

BACKGROUND

The objective of this study was to evaluate the efficacy and toxicity of gemcitabine in patients with chemotherapy-naïve, advanced hepatocellular carcinoma (HCC).

METHODS

Twenty-eight patients with unresectable and nonembolizable HCC who had received no prior systemic chemotherapy and with objectively measurable tumors, adequate liver and renal function, and adequate bone marrow reserve were enrolled on this study. The therapy consisted of gemcitabine 1250 mg/m(2) intravenously over 30 minutes weekly in an outpatient clinic. One course of treatment included three consecutive weekly infusions of gemcitabine and a 1-week rest. Treatment courses were repeated every 4 weeks for a total of six courses unless there was prior evidence of progressive disease.

RESULTS

All 28 patients were evaluable for response and toxicity. A partial response (PR) was achieved in 5 patients, for an overall response rate of 17.8% (95% confidence interval, 2.7-32.9%). Seven patients had stable disease (25%), and 16 patients had disease progression (57.2%). The median survival for all 28 patients was 18. 7 weeks, and, for those patients who achieved a PR, it was 34.7 weeks. The median time to progression was 12 weeks. National Cancer Institute Common Toxicity Criteria Grade 3-4 toxicity consisted primarily of leucopenia (10.7%), anemia (14.3%), thrombocytopenia (10.7%), and hepatotoxicity (14.3%). The spectrum of both hematologic and nonhematologic toxicity was mild, with thrombocytopenia constituting the dose-limiting side effect.

CONCLUSIONS

Gemcitabine shows marginal antitumor activity in patients with advanced HCC, although the response duration is short-lived. Gemcitabine seems to be particularly promising because of its low toxicity profile. Further studies in combination with other active agents are warranted.

Association between seropositivity of antibodies against hepatitis a virus and Helicobacter pylori

Helicobacter pylori and hepatitis A virus (HAV) are documented to share common transmission routes including fecal-oral. This study examined the association between seropositivity of antibodies against H. pylori (anti-HP) and HAV (anti-HAV) via a community-based survey of 40 randomly selected kindergartens in 10 urban and 10 rural areas. Serum samples from 2,047 healthy preschool children and 104 teachers were screened for anti-HP by enzyme-linked immunosorbent assay, and for anti-HAV by microparticle enzyme immunoassay. In children, a low prevalence of anti-HAV (0.44%) was found, in contrast to a high prevalence in their teachers (78.8%); anti-HP seroprevalence was 6.4% for children and 30.8% for teachers. Anti-HAV and anti-HP seropositivities were significantly associated in teachers after adjustment for age, sex, and residential area through multiple logistic regression analysis (multivariate-adjusted odds ratio = 7.3; 95% confidence interval [CI] = 1.4-36.8, P < 0.001). Our findings suggest that HAV and H. pylori may have shared transmission routes in central Taiwan 15 years or more ago, but not any recently.

Phase II study of gemcitabine in patients with advanced hepatocellular carcinoma

BACKGROUND

The objective of this study was to evaluate the efficacy and toxicity of gemcitabine in patients with chemotherapy-naïve, advanced hepatocellular carcinoma (HCC).

METHODS

Twenty-eight patients with unresectable and nonembolizable HCC who had received no prior systemic chemotherapy and with objectively measurable tumors, adequate liver and renal function, and adequate bone marrow reserve were enrolled on this study. The therapy consisted of gemcitabine 1250 mg/m(2) intravenously over 30 minutes weekly in an outpatient clinic. One course of treatment included three consecutive weekly infusions of gemcitabine and a 1-week rest. Treatment courses were repeated every 4 weeks for a total of six courses unless there was prior evidence of progressive disease.

RESULTS

All 28 patients were evaluable for response and toxicity. A partial response (PR) was achieved in 5 patients, for an overall response rate of 17.8% (95% confidence interval, 2.7-32.9%). Seven patients had stable disease (25%), and 16 patients had disease progression (57.2%). The median survival for all 28 patients was 18. 7 weeks, and, for those patients who achieved a PR, it was 34.7 weeks. The median time to progression was 12 weeks. National Cancer Institute Common Toxicity Criteria Grade 3-4 toxicity consisted primarily of leucopenia (10.7%), anemia (14.3%), thrombocytopenia (10.7%), and hepatotoxicity (14.3%). The spectrum of both hematologic and nonhematologic toxicity was mild, with thrombocytopenia constituting the dose-limiting side effect.

CONCLUSIONS

Gemcitabine shows marginal antitumor activity in patients with advanced HCC, although the response duration is short-lived. Gemcitabine seems to be particularly promising because of its low toxicity profile. Further studies in combination with other active agents are warranted.

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

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

Clinical benefit and response in patients with gastric cancer to weekly 24-hour infusion of high-dose 5-fluorouracil (5-FU) and leucovorin (LV)

BACKGROUND

A prospective study evaluated the efficacy and correlation of different outcome measurements, including the WHO response criteria and clinical benefit (CB), to weekly high-dose 5-FU and LV for patients with advanced gastric cancer.

PATIENTS AND METHODS

Thirty-nine chemotherapy-naive patients were enrolled from Sep. 1996 to Oct. 1997. The treatment consisted of a 24-hour continuous infusion of 5-FU 2600 mg/m2 & LV 150 mg weekly for 6 weeks with a subsequent 2-week break. The responses were evaluated by CB and WHO criteria at the end of the 8th week, then at 8-week intervals.

RESULTS

There were 21 male and 18 female patients with a median age of 56 years. The median Karnofsky performance score was 70%. Thirty-six patients were evaluable for WHO criteria, and 12 (33.3%) had partial response, 12 (33.3%) had stable disease and 12 (33.3%) had progressive disease. Twenty-one of the 35 (60%) evaluable patients for CB were found to have a positive response. There was a significant correlation between WHO response and CB. The median survival was 10.5 months for CB responders, while the median survival among the CB non-responders was 5 months only.

CONCLUSIONS

This study found that this regimen yielded a 60% CB, despite a 33% WHO response rate. Improvement in CB resulted in an improvement in survival as well as the correlation between CB and WHO response, and suggested the value of CB as an alternative indicator for clinical response.

Seroepidemiology of Helicobacter pylori infection among preschool children in Taiwan

Helicobacter pylori is associated with chronic antral gastritis that is related to duodenal ulcer, gastric ulcer, and probably gastric adenocarcinoma. Infection with H. pylori during childhood is considered an important risk factor for gastric carcinoma in adult life. To examine the epidemiologic characteristics of H. pylori infection among preschool children in central Taiwan, a community-based survey was carried out in 54 kindergartens in 10 urban townships, 10 metropolitan precincts, and 2 aboriginal townships randomly selected through stratified sampling. Serum specimens of 2,551 healthy preschool children (3-6 years old) randomly sampled from study kindergartens were screened for antibodies to H. pylori by latex agglutination and ELISA methods. Multivariate-adjusted odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated by multiple logistic regression analysis. A total of 207 subjects were antibody-positive, giving a prevalence of 8.1%. The overall seropositive rates were 4.5% in 3-year-old group, 4.4% in 4-year-old group, 9.4% in 5-year-old group, and 11.7% in 6-year-old group. The older the age, the higher the seroprevalence (OR = 3.2, 95% CI = 1.5-6.8 for 3-year-old children versus the 6-year-old children). Seroprevalence was not different between boys and girls. The aboriginal townships had a seroprevalence greater than the urban townships and metropolitan precincts (OR = 2.6, 95% CI = 1.9-3.7). The larger the number of siblings, the higher the seroprevalence (OR = 2.4, 95% CI = 1.0-5.8 for those with no sibling versus those with > or = 3 siblings). In the multiple logistic regression analysis, the seroprevalence of H. pylori remained significantly increased with age, aboriginal township, and large sibship size after multivariate adjustment. A poor water supply system, sewage disposal, and other environmental hygiene in the aboriginal townships might have played some role in infection with H. pylori. The early childhood transmission among siblings might also be an important determinant of H. pylori seropositivity in Taiwan.

Impact of oral submucous fibrosis on chemotherapy-induced mucositis for head and neck cancer in a geographic area in which betel quid chewing is prevalent

In Southeast Asia and Taiwan, betel quid chewing is prevalent. Patients with head and neck cancer who chewed betel quid habitually seem to experience more severe chemotherapy-induced mucositis in our clinical practice. To validate this issue, patients with untreated head and neck cancer who received cisplatin (cDDP) plus a 5-fluorouracil (5-FU)-based neoadjuvant chemotherapy were included in this analysis. Information on the consumption of betel quid, tobacco, and alcohol were recorded before chemotherapy. Oral submucous fibrosis (OSF) was diagnosed clinically according to the fibrotic appearance of the mucosa and trismus. Mucositis was scored according to the World Health Organization criteria, and the mucositis score of the first course of chemotherapy was used for analysis. From December 1993 to April 1996, 120 patients were enrolled in this trial. Neither the betel quid chewing nor the cancer of the oral cavity was to be a significant factor for mucositis. However, clinically diagnosed OSF was found to display a significant correlation with more severe mucositis (p = 0.02). We concluded that in betel quid chewing-prevalent areas, OSF was a risk factor of more severe mucositis in head and neck cancer patients treated by CDDP and 5-FU-based regimens.

Regression diagnostics for the class A regressive model with quantitative phenotypes

Regression diagnostic methods are developed and investigated under the Class A regressive model proposed by Bonney [(1984) Am J Med Genet 18:731-749]. We call a family whose phenotypic distribution does not conform to the same genetic model as the majority of the families an etiotic family. The exact case-deletion approach for identifying etiotic families, based on examining the changes in each model parameter estimate by excluding one family at a time, is very time-consuming. We proposed three alternative diagnostic methods: the empirical influence function (EIF), the one-step approximation, and the approximated one-step approach. These methods can be computed efficiently and were incorporated into the existing software package S.A.G.E. A thorough Monte-Carlo investigation of the performance of the diagnostic methods was conducted and generally supports the EIF approach as the recommended alternative. The phenotypic variance is the parameter whose associated regression diagnostic most frequently and correctly identified etiotic families in the models that were examined. An analysis of body mass index data from 402 individuals in 122 Muscatine, Iowa families is used to illustrate the methods. A Class A regressive model with a recessive major locus and equal mother-offspring and father-offspring correlations provided the best-fitting model. The proposed regression diagnostics identified up to 7.4% of the 122 families as etiotic. As a result of this investigation, case-deletion diagnostic assessment is now a practical component in the analysis of quantitative family data.

Weekly 24-h infusion of high-dose 5-flurouracil and leucovorin in patients with advanced gastric cancer

The effect of biochemical modulation of weekly high-dose 5-fluorouracil (5-FU) 24 h infusion by leucovorin (LV) in the treatment of 39 consecutive patients with advanced gastric cancer without prior chemotherapy from October 1996 to August 1997 was examined. There were 21 male and 18 female patients with a median age of 56 years. The regimen consisted of 5-FU 2600 mg/m2 and LV 150 mg administered by 24 h infusion weekly for 6 weeks followed by a 2 week break. The treatment was repeated every 8 weeks until disease progression, patient refusal or unacceptable toxicity. Placement of a central vascular device and a portable external infusion pump was required in all patients and was used for outpatient treatment. The response to treatment was evaluated every 8 weeks. A total of 395 chemotherapy treatments were given with a mean of 10 (2-24). This response rate was: 33% (12 of 36) partial response (PR) rate, 33% (12 of 36) stable disease (SD) and 33% (12 of 36) progressive disease (PD). In general, the toxicity was mild but two toxic deaths occurred, one due to neutropenic sepsis and the other due to hyperammonemia. The median time to progression was 4 months. The overall median survival was 7 months. The survivals of the PR, SD and PD were 12, 8 and 5 months, respectively. This regimen showed a modest activity against gastric cancer with acceptable toxicity. Weekly 24 h infusion of high-dose 5-FU with LV in an outpatient setting for patients with gastric cancer is feasible and deserves further study as a basis for combination therapy.

Risk of transient hyperammonemic encephalopathy in cancer patients who received continuous infusion of 5-fluorouracil with the complication of dehydration and infection

From 1986 to 1998, 29 cancer patients who had 32 episodes of transient hyperammonemic encephalopathy related to continuous infusion of 5-fluorouracil (5-FU) were identified. None of the patients had decompensated liver disease. Onset of hyperammonemic encephalopathy varied from 0.5 to 5 days (mean: 2.6 +/- 1.3 days) after the initiation of chemotherapy. Plasma ammonium level ranged from 248 to 2387 microg% (mean: 626 +/- 431 microg%). Among the 32 episodes, 26 (81%) had various degrees of azotemia, 18 (56%) occurred during bacterial infections and 14 (44%) without infection occurred during periods of dehydration. Higher plasma ammonium levels and more rapid onset of hyperammonemia were seen in 18 patients with bacterial infections (p=0.003 and 0.0006, respectively) and in nine patients receiving high daily doses (2600 or 1800 mg/m2) of 5-FU (p=0.0001 and < 0.0001, respectively). In 25 out of 32 episodes (78%), plasma ammonium levels and mental status returned to normal within 2 days after adequate management. In conclusion, hyperammonemic encephalopathy can occur in patients receiving continuous infusion of 5-FU. Azotemia, body fluid insufficiency and bacterial infections were frequently found in these patients. It is therefore important to recognize this condition in patients receiving continuous infusion of 5-FU.

Immune status in preschool children born after mass hepatitis B vaccination program in Taiwan

A mass hepatitis B vaccination program began in Taiwan in 1984. In order to determine the immune status of hepatitis B virus (HBV) infection among preschool children, a total of 25 kindergartens in 20 townships and metropolitan precincts in central Taiwan were randomly selected through stratified sampling. Serum specimens of 2130 healthy preschool children aged 2-6 years old were screened for the HBV markers and liver function in 1996. HBV surface antigen (HBsAg), antibody against HBsAg (anti-HBs) and antibody against HBV core antigen (anti-HBc) were tested by reverse passive hemagglutination (RPHA), enzyme immunoassay (EIA) and radioimmunoassay (RIA) using commercial kits. HBV vaccination rate of the preschool children was 98%, and complete vaccination rate (three or four doses of HBV vaccine) was 94%. The HBsAg seropositive rate was 4.5% among incomplete vaccinees and 1.3% among complete vaccinees. The anti-HBs was detectable in 1637 of 2000 complete vaccinees (81.9%) and in 53 of 88 incomplete vaccinees (60.2%). The overall prevalence rate of anti-HBc was 2.4% (52 of 2130). The older the age, the lower the anti-HBs seropositive rate. The anti-HBs seropositive rats for complete vaccinees were 100% at 2 years old and 75% at 6 years old. There were no significant differences in HBsAg-seropositive rates and anti-HBs-seropositive rates among different residential areas or ethnic groups. There were three children who were seropositive on HBsAg, anti-HBs and anti-HBc, whether they were infected by the vaccine-induced escape mutant of HBV deserves scrutiny.

Hypopharyngeal carcinoma with clinical peritoneal carcinomatosis: a report of two patients

Most patients with hypopharyngeal carcinomas show advanced disease, either at the primary site or in the neck, at the time of diagnosis. Despite intensive therapy, a great number of recurrences and distant metastases can be observed. The most common metastatic sites are the lung and bone, and only in autopsy cases has peritoneum carcinomatosis been mentioned as a metastatic site. Since January 1992, two of 78 patients (2.3%) with advanced hypopharyngeal squamous cell carcinomas (SCCs) treated initially by chemotherapy in our department developed clinical peritoneal carcinomatosis during their natural courses. Both patients were man patients with advanced locoregional disease at stage T4N3. Their clinical peritoneal carcinomatosis appeared during chemotherapy, with good disease control above the clavicle. Both patients eventually died of sepsis within 1 month after diagnosis of the peritoneal carcinomatosis. The authors suggest that peritoneal carcinomatosis is not as rare as previously believed, and should be included in the differential diagnosis in patients with advanced hypopharyngeal SCC with abdominal symptoms. Peritoneal carcinomatosis appears to be refractory to chemotherapy, and carried a poor prognosis in patients in the present study.

Inhibition of human colon cancer malignant cell behavior and growth by antisense epidermal growth factor receptor expression vector

Human colon cancer cells utilize the epidermal growth factor (EGF) family of growth factors and the receptor for these growth factors (EGFR) in sustaining their malignant phenotype. Disrupting EGFR expression by expressing antisense EGFR RNA (through transfection with an appropriate antisense EGFR expression vector under metallothionein promoter control) downregulated the malignant behavior of human colon cancer Moser cells and blocked the ability of exogenous EGF in stimulating malignant cell behavior. The antiproliferative effect of antisense EGFR expression vector was determined in three human colon cancer cell lines (Moser, HCT116 and HT29 possessing different biological properties and rate of proliferation) in an in vitro therapeutic setting using an antisense EGFR expression vector under the control of a viral promoter. Different degree of inhibition was achieved for each cell line after one dose of antisense treatment. The differences in the antiproliferative effect observed may be due to differences in the rate of proliferation and/or recovery from antisense effect, and the differences in transfection efficiency among the cell lines.

Weekly 24 h infusion of high-dose 5-fluorouracil and leucovorin in patients with biliary tract carcinomas

From October 1995 to June 1997, 19 chemotherapy-naive patients with pathology-proven locally advanced or metastatic biliary tract carcinomas (BTC) were enrolled. The regimen consisted of 5-fluorouracil (5-FU) 2600 mg/m2 and leucovorin (LV) 150 mg by weekly 24 h infusion for 6 weeks and followed by a 2 week break. The treatment was terminated if disease progressed, the patient refused or unacceptable toxicity occurred. All patients required a Port-A catheter insertion and were treated at outpatient clinics by portable infusion pumps. There were 12 males and seven females with a median age of 62 years (range 45-77). The primary tumor sites were nine intrahepatic cholangiocarcinomas (CC), three perihilar CC, one distal BTC and six gallbladder cancers. A total of 179 chemotherapy sessions were given with a mean of 9.5 (range 2-18). Eighteen patients were evaluable for response. The response rates were: 33% (six of 18) partial response (PR), 39% (seven of 18) stable disease (SD) and 28% (five of 18) progressive disease (PD). All of the patients were evaluable for toxicity. The most common toxicities were mild fatigue (nine of 19, 47%), loss of appetite (nine of 19, 47%), skin hyperpigmentation (five of 19, 26%) and diarrhea (two of 19, 11%). Only one patient had grade IV myelotoxicity with sepsis but without treatment-related death. The median time to progression was 4 months. The overall median survival time was 7.0 months. The median survival time of the PR was not reached, SD was 8.0 months and PD 3.5 months. In conclusion, weekly high-dose 5-FU with LV by 24 h infusion in an outpatient setting for patients with BTC is effective, only mildly toxic and deserves further study.

The effect of chronic alcohol use on the heart before and after transplantation in an experimental model in the rat

BACKGROUND

Alcohol has potential deleterious effects on donor heart function. This study was conducted in rats to determine whether long-term alcohol ingestion produces impaired hemodynamic performance while maintaining a normal left ventricular ejection fraction in donor hearts before transplantation and whether donor cardiac function is affected after heart transplantation.

METHODS

Rats fed 30% alcohol in their drinking water for 12 weeks were compared with rats fed a normal diet. Left ventricular ejection fraction was measured by echocardiography with Simpson and single plane Dodge formulas in living sedated rats after 10 and 12 weeks of alcohol feeding. Explanted heart function was assessed before and 3 days after heterotopic heart transplantation (no immunosuppression) with a Langendorff preparation.

RESULTS

Blood ethanol levels at 4 and 8 weeks were 0.08 +/- 0.04 and 0.08 +/- 0.09 gm/dl. Left ventricular ejection fraction was similar in the group fed an alcohol diet for 12 weeks when compared with the control group (65.4% +/- 1.6% vs. 66.5% +/- 2.9%, p = 0.33). Explanted alcohol-fed hearts before transplantation had significantly lower maximum and developed pressures and had a blunted response to 0.1 ml 10(-9) mol/L isoproterenol. After transplantation alcohol-fed hearts had significantly lower maximum and developed pressures and decreased maximum rates of pressure rise and pressure decline. Allografts (ACI to Lewis) exhibited decreased function in comparison with isografts (ACI to ACI).

CONCLUSIONS

Alcohol feeding for 12 weeks in rats does not affect pretransplantation left ventricular ejection fraction, but it impairs explanted heart function, both before and after transplantation, resulting in a subclinical cardiomyopathy that is worsened by the presence of allograft rejection. Long-term alcohol exposure and rejection have independent, additive detrimental effects on left ventricular performance of the transplanted heart. Alcohol-exposed hearts may not be suitable donors.

Clinical treatment in colonoscopic perforation: a comparison of surgical and conservative management

BACKGROUND

Successful management of colonoscopic perforation by conservative treatment has been reported, but management remains controversial. Delayed surgery in some situations may lead to an irretrievable result. How to make the best decision? A retrospective study was designed to address this challenge.

METHODS

From the period October 1982 and December 1995, 9214 consecutive colonoscopic examinations at Taichung Veterans General Hospital were reviewed.

RESULTS

Twenty perforations (0.22%) related to the procedure were found. Of those 16 occurred during diagnostic colonoscopies, and four, during therapeutic colonoscopies. Fifteen perforations caused by diagnostic colonoscopies were treated by surgery, one perforation caused by diagnostic colonoscopy and the four by therapeutic colonoscopies were treated by non-surgical methods.

CONCLUSIONS

A standard text on large bowel surgery recommends laparotomy for most cases of colonoscopic perforations. In experience here, however, non-operative management was indicated if the perforation was small with no signs of general peritonitis, and the patient's condition was good. However, if the patients deteriorated with non-operative treatment, immediate laparotomy is indicated.

The VIP regimen effective treatment to refractory choriocarcinoma: a case report

This is a case report of a female patient who tried another regimen after EMA-CO regimen failed. A 30-year-old female, gravida 4, para 2, abortus 2, blood grouping O (grouping B of her husband), was a victim of choriocarcinoma of the uterus and was resistant to multiple combination regimens of chemotherapy (EMA-CO, EMA-PE, BEP). She was finally cured by the VIP regimen of chemotherapy. The VIP regimen may be considered as an effective protocol to cure refractory choriocarcinoma.

Induction of DNA topoisomerase II-mediated DNA cleavage by beta-lapachone and related naphthoquinones

Recent studies have suggested that 3,4-dihydro-2,2-dimethyl-2H-naphtho[1,2-b]pyran-5,6-dione (beta-lapachone) inhibits DNA topoisomerase I by a mechanism distinct from that of camptothecin. To study the mechanism of action of beta-lapachone, a series of beta-lapachone and related naphthoquinones were synthesized, and their activity against drug-sensitive and -resistant cell lines and purified human DNA topoisomerases as evaluated. Consistent with the previous report, beta-lapachone does not induce topoisomerase I-mediated DNA breaks. However, beta-lapachone and related naphthoquinones, like menadione, induce protein-linked DNA breaks in the presence of purified human DNA topoisomerase IIalpha. Poisoning of topoisomerase IIalpha by beta-lapachone and related naphthoquinones is independent of ATP and involves the formation of reversible cleavable complexes. The structural similarity between menadione, a para-quinone, and beta-lapachone, an ortho-quinone, together with their similar activity in poisoning topoisomerase IIalpha, suggests a common mechanism of action involving chemical reactivity of these quinones. Indeed, both quinones form adducts with mercaptoethanol, and beta-lapachone is 10-fold more reactive. There is an apparent correlation between the rates of the adduct formation with thiols and of the topoisomerase II-poisoning activity of the aforementioned quinones. In preliminary studies, beta-lapachone and related naphthoquinones are found to be cytotoxic against a panel of drug-sensitive and drug-resistant tumor cell lines, including MDR1-overexpressing cell lines, camptothecin-resistant cell lines, and the atypical multidrug-resistant CEM/V-1 cell line.

Intensive chemotherapy plus recombinant human granulocyte-colony stimulating factor support for distant metastatic nasopharyngeal carcinoma. A preliminary report

Nasopharyngeal carcinoma (NPC) has been shown to be highly responsive to chemotherapy. The major limiting toxicity was myelotoxicity. Recently, the role of granulocyte colony-stimulating factor (G-CSF) in reducing chemotherapy-induced neutropenic sepsis has been well established. In this study, we tested whether recombinant human G-CSF (rhG-CSF) could effectively support the bone marrow function in both previously untreated and pretreated metastatic NPC patients receiving intensive chemotherapy. Twelve patients with distant metastatic disease, 5 newly diagnosed (group A) and 7 pretreated patients (group B), were enrolled to receive BEC (bleomycin, epirubicin and cisplatin), followed by rhG-CSF support (50 microg/m2 s.c. daily for 10 days) every 4 weeks for two cycles. Four patients in group A completed the treatment as scheduled while only 2 patients in group B did. After the first treatment cycle, 6 patients (50%) had grade III-IV myelosuppression. Five of the patients were from group B. The mean values of the white cell count nadir were 2,680 (range 1,200-3,700) in group A and 1,343 (range 400-2,900) in group B (p = 0.0386). Neutropenia-associated fever occurred in 7 patients, 6 of whom had received previous treatment. There were 2 deaths due to toxicity, and both patients had liver metastases within 6 months following radiation. After 24 months of follow-up, only 1 patient is still alive. Our preliminary results suggest that in previously treated metastatic NPC patients, bone marrow suppression is still the major limiting toxic side effect of aggressive chemotherapy, especially for those patients with liver recurrences within 6 months after irradiation and despite rhG-CSF support.

Correlation between computed tomographic density of lymph node metastases and response to cisplatin-based chemotherapy in patients with head and neck squamous cell carcinoma in an area in which betel quid chewing is prevalent

BACKGROUND

Identifying the factors predicting response to chemotherapy is important for patients with head and neck squamous cell carcinoma (HNSCC). It allows more rational selection of subsets of patients who may benefit from multidisciplinary treatment. Correlation of lymph node density in contrast-enhanced computed tomographic (CT) scans of HNSCC with response to chemotherapy was observed in the recent literature. This prospective study was designed to validate this clinical issue.

METHODS

From January 1992 to March 1995, 71 patients with untreated HNSCC were included in this study in which the following criteria were met: 1) a lymph node > 3 cm by physical examination or > or = 2 cm by scanographic examination; 2) clinically evaluable disease treated by cisplatin-based neoadjuvant chemotherapy; and 3) availability of a pretherapeutic contrast-enhanced CT scan showing the cross-sections of relevant lymph node metastases. The density of the largest lymph node was compared with that of the nuchal muscles by a radiologist blinded to the patient's therapeutic outcome. A lymph node was classified as hypodense if more than 33% of the lymph node surface area was comprised of a hypodense zone, and isodense if less than a third of the lymph node surface area was comprised of a hypodense zone.

RESULTS

Fifty-one patients (72%) had the largest lymph node classified as hypodense, and 63 patients (89%) were found to have extranodal spread (ENS) in the relevant lymph nodes. Fifty-nine patients were betel quid chewers. Lymph node density was not related to T classification, primary site, or histologic differentiation of the primary tumor. There was also no correlation between lymph node density and lymph node N classification. The lymph node chemotherapy response rate was 35% (7 of 20) of the isodense group and 47.1% (24 of 51) of the hypodense group (P = 0.36). ENS was found to have no impact on the chemotherapy response.

CONCLUSIONS

Computed tomographic density of lymph node metastases did predict chemotherapy response in the HNSCC patients in the current study from an area in which betel quid chewing is prevalent.

Prognostic factors of locoregionally recurrent nasopharyngeal carcinoma--a retrospective review of 182 cases

Locoregional relapse is the major cause of failure of nasopharyngeal carcinoma (NPC) after radical radiation therapy. The prognosis of such patients is dismal, and the factors related to the outcome are not well identified. Between January 1983 and December 1989, 1,168 new patients with biopsy-proven NPC were seen at this hospital. Eight hundred and eighty-three of these patients were treated uniformly with radical external irradiation and intracavitary treatment with or without chemotherapy. The clinical courses, retreatment outcomes, and prognostic factors for locoregional relapse and subsequent distant metastasis were analyzed. During the follow-up period of 3-10 years or until death, 182 patients (20.6%) developed locoregional relapses without distant metastasis initially. T stage and age were significant prognostic factors for locoregional recurrence. In contrast, histopathologic subtype, N stage, sex, and systemic chemotherapy were not. There were 36 patients (19.8%) who developed subsequent distant metastasis with or without retreatment. The median time from locoregional relapses to distant metastasis was 6 months in this study, and bone was the most frequent and the earliest site of distant metastasis. The N stage at diagnosis, the initial disease-free interval, the presence of neck nodal disease at relapse, and age were the significant factors for predicting the subsequent distant metastasis in locoregionally recurrent NPC patients. We recommend that additional systemic chemotherapy should be considered for retreatment of locoregional relapsed NPC, not only for enhancement of local control but also for eradicating microscopic metastasis as anticipated.

Microbiologic assay for detection of antimicrobial agents in urine

Antimicrobial therapy can be a confounding factor in the diagnosis of urinary tract infection and is not always reported to laboratories by physicians. We developed a microbiologic assay for screening urine specimens for antimicrobial agents. Bacillus stearothermophilus was used as the indicator bacteria. A total of 1,921 urine specimens from three hospitals in Taiwan were screened using this assay. Of the samples assayed, 1,293 were positive for antimicrobial agents. Agreement between information provided by physicians and laboratory findings was 68.5% (419/612). In the presence of antimicrobial agents in the urine samples, the isolation of yeasts and Pseudomonas aeruginosa increased dramatically, from 4.5 to 19.5% and 4.2 to 13.2%, respectively. Additionally, Escherichia coli was more resistant to gentamicin (75.3% vs 48.7%, p < 0.0001), norfloxacin (85.2% vs 64.6%, p = 0.0006) and co-trimoxazole (58.5% vs 35.5%, p = 0.0018). In view of the high rate of occurrence of antimicrobial agents in urine specimens and the lack of information provided by most physicians to laboratories, a screening method to detect the presence (or absence) of antimicrobials in urine specimens may be a useful tool particularly in areas such as Taiwan where antimicrobial agents are commonly abused.