Novel cytokine release inhibitors. Part III: Truncated analogs of tripterine

Truncated analogs of tripterine as cytokine (IL-1 alpha, IL-1 beta, TNF-alpha, IL-6, and IL-8) release inhibitors are discussed.

Effect of Pseudomonas fluorescens on beef discoloration and oxymyoglobin oxidation in vitro

The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas fluorescens or sterile nutrient broth (control) in an airtight vessel. P. fluorescens samples showed greater metmyoglobin formation and oxygen consumption than controls. The P. fluorescens population in the reaction vessels was correlated with metmyoglobin formation (r = 0.85, P < 0.05) and oxygen consumption (r = 0.91, P < 0.05). When P. fluorescens and oxymyoglobin were combined in an airtight vessel, reducing the headspace from 13 ml and 9 ml to 3 ml resulted in greater metmyoglobin formation (P < 0.05). In the meat study, beef cores prepared from longissimus lumborum were inoculated with P. fluorescens (10(7) CFU/cm2) or sterile peptone water (control), packaged under 1% O2 (+99% N2), air, or 100% O2 and stored at 4 degrees C. Inoculated beef cores showed higher bacterial loads and metmyoglobin formation than their respective controls during 10 h storage in 1% O2, 3 days in air, and 7 days in 100% O2 (P < 0.05). This finding indicated that P. fluorescens could accelerate beef discoloration. Overall, studies demonstrated that oxygen consumption concomitant with P. fluorescens growth decreased partial oxygen pressure, which accelerated oxymyoglobin oxidation.

OphthWeb---cost-effective telemedicine for ophthalmology

'OphthWeb' is an ophthalmic electronic medical record that can be accessed locally and globally via the Internet. OphthWeb can provide secure multimedia patient data to doctors, patients, and health care providers at any time and in any place. Patients have secured access to their own records in the convenience of their homes or during any emergency at any time or place around the world. OphthWeb provides interactive educational information and answers frequently asked questions by way of multimedia images on the Worldwide Web. A data transmission trial was conducted between the Xiamen Eye Centre in the Fujian province in southern China and Singapore. Clinical records, voice messages, and fundus and slit-lamp images were transmitted from Xiamen, and an off-line dialogue by e-mail and Internet-relay chat was conducted. The time delay from transmission to receipt was 30 minutes, which would be adequate to respond to most ophthalmic emergencies. This pilot project will promote computer literacy among doctors, and inter-institutional interaction in the health care profession. OphthWeb can provide telemedicine and electronic medical records at a low cost and great convenience.

Novel cytokine release inhibitors. Part I: Triterpenes

Tripterine and closely related triterpenoid derivatives as IL-1 beta release inhibitors are discussed.

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

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

Undiagnosed acute myocardial infarction in the accident and emergency department: reasons and implications

Because acute myocardial infarction causes significant morbidity and mortality, a correct diagnosis in the accident and emergency department is important so that early treatment including thrombolytic therapy can be given. The aim of this study was to evaluate the reasons for missed diagnosis of acute myocardial infarction in the accident and emergency department, and the implications. All patients admitted to our coronary care unit in 1995 with the confirmed diagnosis of acute myocardial infarction were analysed retrospectively. The demographic data, clinical profiles, diagnosis made at the accident and emergency department and feasibility of thrombolytic therapy were assessed. Analysis of the electrocardiography by the accident and emergency department doctor and the coronary care unit doctor were also compared. Forty-three out of 159 patients (27.0%) with acute myocardial infarction were missed in the accident and emergency department. The diagnoses made were mostly angina or chest pain. Absence of chest pain (25.6%) [vs. 10.2% in correct diagnosis group, p < 0.05] and lack of ST elevation in electrocardiograph (62.8%) [vs. 18.1% in correct diagnosis group, p < 0.0001] were the main predisposing factors for missed diagnosis. Because of missed diagnosis, only 25.6% (vs. 67.2% in correct diagnosis group, p < 0.01) of patients were admitted to the coronary care unit. About one-third (34.9%) of missed diagnosis patients (vs. 6.0% in correct diagnosis, p < 0.01) did not receive thrombolytic therapy because of delayed diagnosis. In the missed diagnosis group, 34.8% of them might be avoidable, if electrocardiogram interpretation was more accurate. More education and training of the involved medical personnel might improve the overall situation.

Weekly etoposide, epirubicin, cisplatin, 5-fluorouracil and leucovorin: an effective chemotherapy in advanced gastric cancer

In order to optimize the therapeutic index of combining etoposide, epirubicin, cisplatin, 5-fluorouracil (5-FU), leucovorin (EEPFL) chemotherapy in the treatment of advanced gastric cancer, a trial of a novel schedule of weekly administration was conducted. Weekly EEPFL treatment consisted of a concomitant boost of etoposide 40 mg m(-2) i.v. over 30 min, epirubicin 10 mg m(-2) i.v. over 5 min to a backbone regimen, weekly PFL chemotherapy with cisplatin 25 mg m(-2), 5-FU 2200 mg m(-2), leucovorin 120 mg m(-2) given simultaneously by 24-h i.v. infusion. Response, survival and toxicity were evaluated. Forty-two patients were studied. Median age was 69 (range 31-84) years. Twenty-six per cent of patients showed complete response and 45% partial response. The overall response rate was 71% (95% confidence interval 58-84%). For a total of 507 weekly EEPFL cycles delivered, the incidence of grade 4 leucopenia was 1% of cycles. One patient died of neutropenia septicaemia. There was no other grade 4 toxicity. Grade 3 and 2 leucopenia occurred in 7% and 14% of cycles. The incidence of grade 3 and 2 mucositis was 1% and 3% of cycles. Grade 3 and 2 diarrhoea occurred in 0.4% and 1.6% of cycles. Overall median survival was 10 months (range 3-41+ months). Weekly EEPFL chemotherapy is an effective regimen with tolerable toxicities in the treatment of advanced gastric cancer. A randomized controlled clinical trial to formally assess the efficacy and benefit of EEPFL chemotherapy is under way.

Effects of alpha-tocopherol on metmyoglobin formation and reduction in beef from cattle fed soybean or cottonseed meal diets

Hereford-Angus crossbred heifers were fed a cottonseed meal-based diet containing gossypol (14 mg free gossypol x kg body wt(-1) x d(-1); CSM), a soybean meal-based diet (SBM), or alpha-tocopherol-supplemented diets (4,036 IU vitamin E x heifer(-1) x d(-1) for 90 d; CSM+E and SBM+E). The effects of diet on color stability and aerobic metmyoglobin reducing ability of beef longissimus lumborum (LL) and psoas major (PM) were evaluated. The CSM containing gossypol did not affect alpha-tocopherol concentration, a* value, or hue angle value of beef muscles obtained from control or vitamin E-supplemented cattle compared to their SBM counterparts. Vitamin E supplementation increased endogenous alpha-tocopherol concentrations and color stability in LL and PM muscles compared with controls from either diet (P < .05). In the aerobic metmyoglobin reducing ability study, LL and PM muscles were stored in 1% O2:99% N2 (a pigment-oxidizing atmosphere) for 48 h and subsequently stored aerobically for an additional 48 h. Within the LL, alpha-tocopherol supplementation delayed metmyoglobin formation in LL exposed to 1% O2 (P < .05). Within the PM, no differences in metmyoglobin formation were found between controls and vitamin E treatments in SBM or CSM diets. Relative aerobic metmyoglobin reduction was the same (P > .05) in LL and PM muscles within SBM or CSM diets for control and vitamin E treatments. Alpha-tocopherol did not seem to affect metmyoglobin aerobic reducing ability in LL and PM muscles.

Beef color update: the role for vitamin E

Dietary supplementation of livestock with vitamin E results in improved quality of meat subsequently obtained from these animals. The effect is especially noteworthy in cattle, in which the primary effects are delayed discoloration and lipid oxidation. A threshold level of alpha-tocopherol in muscle ensures a detectable effect; dietary strategies for attaining this threshold must consider tocopherol status of cattle arriving at the feedyard and duration and level of supplementation. The alpha-tocopherol concentration in muscle must be determined before proper interpretation of experimental results can be made. Muscles vary in their color stability, and this relative difference is not changed by vitamin E supplementation. Several in vitro models have been used to characterize the interaction between alpha-tocopherol, lipid oxidation, and oxymyoglobin oxidation. Alpha-tocopherol seems to exert its color-stabilizing effect by indirectly delaying oxymyoglobin oxidation via direct inhibition of lipid oxidation. However, recent results demonstrating a protective effect of alpha-tocopherol toward oxymyoglobin in low-oxygen atmospheres indicate that additional mechanisms may exist. A better understanding of the fundamental bases for protection of water-soluble myoglobin by lipid-soluble alpha-tocopherol is needed to optimize this beneficial effect.

Starting thrombolytic therapy for patients with acute myocardial infarction in Accident and Emergency Department: from implementation to evaluation

OBJECTIVE

To evaluate the effectiveness of initiating thrombolysis for patients with acute myocardial infarction (AMI) in the Accident and Emergency Department.

METHODS

From January 1993 to December 1995, all AMI patients who were admitted to the United Christian Hospital and given thrombolytic therapy were studied. The patients' demographic data, time and mode of presentation, site of myocardial infarction, treatment modality and timing, and complications related to AMI or treatment were recorded prospectively in our AMI database. The frequency of thrombolysis administered in Accident and Emergency Department and Coronary Care Unit, as well as the median door-to-needle time (time interval between hospital arrival to initiation of thrombolytic therapy) were compared. Cases of inappropriate thrombolysis and complication were also analyzed.

RESULTS

Over these 3 years, 257 patients received thrombolysis in the United Christian Hospital. The percentage of patients receiving thrombolysis in Accident and Emergency Department increased from 3.2% in 1993 to 12.3% in 1994, and to 39.4% in 1995. The median time interval between arrival to hospital and thrombolysis (door-to-needle time) was 25 minutes, compared with 81 minutes in the Coronary Care Unit. The door-to-needle time also improved over these 3 years: from 95 minutes in 1993 to 75 minutes in 1995 in Coronary Care Unit group, and from 35 minutes in 1993 to 20 minutes in 1995 in the Accident and Emergency Department group. Over these 3 years, 2 cases of inappropriate thrombolysis were reported but these did not result in any mortality. Four complications from thrombolytic therapy were reported, and these were managed appropriately by the staff in Accident and Emergency Department and did not result in mortality.

CONCLUSIONS

Starting thrombolytic therapy in Accident and Emergency Department is safe and effectively decreases the door-to-needle time.

Catalase prevents estradiol-induced chondrocyte cytotoxicity

Osteoarthritis is a common geriatric disease and estrogen may play an important role in this disease. Estradiol may cause chondrocyte damage as suggested by in vitro and in vivo data. One of the possible mechanisms of estradiol-induced chondrocyte damage was thought to be related to free radicals. Whether catalase, a known free radical scavenger, can prevent estradiol-induced chondrocyte damage was tested using a chondrocyte culture system. The results of this study suggest that catalase can significantly reduce the estradiol-induced damage to chondrocytes. Apparently, catalase alters the molecular structure of estradiol as indicated by the absorption spectrum of estradiol with time. The modified estradiol may decrease its toxicity to the chondrocytes. However, the contents of free radicals in the treated chondrocytes have no significant difference from the untreated control cells. Studies to further investigate the mechanism or prevention of estradiol-induced chondrocyte damage in osteoarthritis are warranted.

Mechanism-based inactivation of human cytochrome P450 3A4 by grapefruit juice and red wine

Grapefruit juice is well documented to cause clinically significant increases in the plasma concentrations of many therapeutic agents. These interactions are believed to be mediated via inhibition of intestinal cytochrome P-450 3A4 (CYP3A4) by flavonoids and/or other chemicals in grapefruit juice, although the mechanism of that inhibition has not been fully characterized. Like grapefruit juice, red wine contains large amounts of flavonoids and other xenobiotics which could also mediate CYP3A4 inhibition. In this study, we investigated the mechanism of inhibition of CYP3A4 by grapefruit juice and also examined the ability of red wine to inhibit this enzyme. Both red wine and grapefruit juice potently inhibited CYP3A4 activity in a concentration-dependent manner. At 8% of natural strength, enzyme activity was inhibited almost 90 and 84%, respectively, by grapefruit juice and red wine. In contrast, white wine did not appreciably inhibit CYP3A4 activity. Grapefruit juice irreversibly inactivated CYP3A4 in a time- and NADPH-dependent manner. The rate of inactivation mediated by grapefruit juice was similar to that mediated by troleandomycin, a potent mechanism-based inhibitor of CYP3A4. Red wine also inactivated CYP3A4 but at a rate approximately 16% that of grapefruit juice. Inhibition of CYP3A4 by red wine is primarily reversible in nature. The clinical implications of this research are discussed.

Emergency defibrillation performed by coronary nursing staff: A pilot report

The time taken to initiate defibrillation is a key factor in determining survival after cardiac arrest; all first-responding medical or paramedical personnel are thus recommended to receive training in defibrillation skills. We have recently established a working programme that allows trained coronary care nurses to defibrillate in emergencies. Prospective data collected from 1 October 1996 to 31 January 1997 showed that a total of 11 witnessed episodes of ventricular fibrillation or pulseless ventricular tachycardia occurred in nine patients, and were defibrillated by nurses. All the defibrillations were started within 1 minute of cardiac arrest. In five patients, defibrillation was commenced before the arrival of the crash team of doctors; three of the five patients survived. There were no violations of the resuscitation protocol or complications relating to defibrillation. Through programmed training in advanced cardiac life-support, coronary care nurses are capable of providing safe and prompt defibrillation. The importance of training and re-certification is also stressed.

Proliferation and cell death in oligodendrogliomas

The rates of cell proliferation and of cell loss influence the growth rate of a tumour and reflect genetic changes. We studied proliferation and apoptosis in oligodendrogliomas and their relationship to progression of the tumours. Thirty-two cases of oligodendroglioma were retrieved spanning a 10-year period. The diagnosis and grade were reviewed and follow-up data obtained. Mitotic index (MI) and apoptotic index (AI) were determined from haematoxylin and eosin (H & E) stained sections. A labelling index (LI) of proliferating cells was obtained using the MIB1 antibody to the Ki-67 antigen. A further index of apoptosis was obtained using in situ end-labelling of DNA strand breaks (TUNEL index, TI). Fourteen cases were graded as II, 18 as III (1993 WHO). LI was significantly higher in grade III than in grade II tumours (P < 0.01) but the difference in apoptotic indices between grades was not significant. There was a significant (P = 0.036) positive correlation between the logarithms of TI and LI. Construction of survival curves demonstrated a significant difference in survival according to histological grade (P < 0.05). Stratification of cases by LI alone did not predict significantly different survival outcomes, and apoptotic indices did not demonstrate a relationship to survival. A positive relationship was demonstrated between proliferation and apoptosis in oligodendrogliomas. The levels of apoptosis observed indicate that this phenomenon may have an important influence on the overall rate of tumour growth.

Injection sclerotherapy in the treatment of rectal prolapse in infants and children

PURPOSE

The aim of this study was to examine the efficacy of injection sclerotherapy as treatment for persistent rectal prolapse.

METHODS

The records of 28 patients with rectal prolapse treated with injection sclerotherapy over a 16-year period were reviewed. Initial management included assessment and correction of predisposing factors. If rectal prolapse persisted or if the prolapse required repeat emergency or operating room reduction, injection sclerotherapy was performed. The sclerosing agent included D50W in 21 patients (sole agent in 15, combined with ethanolamine oleate in four, and with phenol 5% in two). Phenol 5% alone was used in six patients, and 25% saline was used in one patient. Number of injections, recurrences, and complications were reviewed.

RESULTS

Two patients were lost to follow-up, and one patient was cured once a polyp was recognized and removed. Of the remaining 25 patients, 21 were cured. Sixteen required one injection, three required two injections, and two required three injections (64% cure rate after one injection, 84% cure rate after three injections). There were 4 of 25 failures: two went on to low anterior resection after having failed two injections each; one patient was treated with Thiersch cerclage and injection after two failed injections; and one patient did not respond after three injections but had less severe prolapses. Of those injected with D50W alone, 13 of 14 were cured with injection sclerotherapy. Nine received one injection, two received two injections, and two received three injections (64% cure rate after one injection, 93% cure rate after three injections). The only complication was excessive oozing at the injection site in one patient. He was simply observed in hospital overnight. Follow-up averaged 33 months. The only significant underlying abnormality in our patient population was spina bifida in one patient. This patient was cured with injection therapy. Cystic fibrosis was ruled out by clinical examination and sweat chloride test in all patients. Constipation was the most common condition identified with the onset of rectal prolapse (15 of 28).

CONCLUSIONS

Injection sclerotherapy is simple and should be considered as the first line treatment of recurrent rectal prolapse after failure of conservative measures. D50W is effective, easily available, inexpensive, and associated with few complications.

The cloning, expression and characterization of a cellobiase gene encoding a secretory enzyme from Cellulomonas biazotea

A 4.7-kb DNA insert encoding a secretory cellobiase (Cba) was cloned from Cellulomonas biazotea in Escherichia coli using an excretion vector, pM. Host cells transformed with the recombinant construct, designated pBZ4.7, were able to utilize cellobiose as the sole carbon source. Part of the Cba activity encoded by pBZ4.7 could be detected in the periplasm and even in the culture supernatant. The Cba protein was purified from the culture supernatant and analyzed by SDS-PAGE to have an apparent M(r) of 86,000. The insert consisted of two PstI fragments with lengths of 0.75 and 3.95 kb, both of which were found to be crucial for expressing the Cba activity. Sequencing of the first 3.95 kb of the insert revealed that the coding sequence for Cba, designated the cba gene, was 2484 bp long. Comparison of the deduced Cba sequence with those of published beta-glucosidases revealed a potential active site located at the N-terminal portion of the former. The cba gene has a high G + C content of 76.4% and is flanked by a putative ribosome-binding site and potential transcriptional termination signals upstream and downstream from its coding sequence, respectively.

The prediction of surgically induced refractive change from corneal topography

PURPOSE

To develop a method to predict the refractive power of the cornea from corneal topography.

METHODS

We reviewed preoperative and postoperative cycloplegic refraction, keratometry, and corneal topography in 40 eyes of 40 patients who had undergone photorefractive keratectomy, radial keratotomy, myopic keratomileusis in situ, or hyperopic lamellar keratoplasty. For each axial dioptric power map, we calculated the aspheric ellipsoid that best fit that map. Central corneal points were weighted more heavily than peripheral points, based on the Stiles-Crawford effect. The equation of the best-fit ellipsoid yielded the spherical and astigmatic power and axis for each cornea preoperatively and postoperatively.

RESULTS

The preoperative corneal spherical and astigmatic powers measured by the best-fit method were consistent with the spherical and astigmatic powers measured by keratometry and simulated keratometry. The change in corneal spherical power predicted by the best-fit method was significantly (P < .05) more accurate at predicting the change in spherical equivalent refraction than change either in spherical equivalent keratometry or in spherical equivalent simulated keratometry. The prediction of the astigmatic change was less precise than that of the spherical, but the best-fit method was the most accurate.

CONCLUSIONS

The best-fit method is more accurate than simulated keratometry and standard keratometry are in evaluating corneal refractive power after refractive surgery. An improved method of calculating corneal refractive power may facilitate subjective refraction after refractive surgery, improve the accuracy of intraocular lens power calculation for eyes that have had previous refractive surgery, and improve ablation profiles for excimer laser refractive surgery.

Mandibular odontogenic fibrosarcoma. Case report

A rare case of mandibular odontogenic fibroma is presented which transformed to a stage 1A odontogenic fibrosarcoma with a local recurrence after surgical resection and unusually delayed pulmonary metastases eight years later. Prolonged follow-up of these patients after complete surgical resection, including regular chest X-rays, is recommended.

Central diabetes insipidus in a newborn with deletion of chromosome 7q

We report an infant with midline craniofacial defects and holoprosencephaly due to chromosome 46, XY, del (7) (pter-->q34) who presented at 1 week of age with central diabetes insipidus. The importance of hypothalamic-pituitary endocrine investigation in patients with this syndrome, and more generally, in patients with midline craniofacial malformation or holoprosencephaly is emphasized. As infants with chromosome 7q deletion bear close phenotypic resemblance to infants of Trisomy 13, chromosomal confirmation and karyotype banding is mandatory to establish an accurate diagnosis and for genetic counselling of their parents.

Photorefractive keratectomy for the treatment of compound myopic astigmatism using the ablatable mask

Eight eyes of 8 patients with compound myopic astigmatism were treated with excimer laser photorefractive keratectomy (PRK) using a hand-held ablatable mask in conjunction with the Summit excimer laser. The attempted correction ranged from -1.25 to -400 dioptres (D) of astigmatism and 0 to -8.00 D of myopia. All eyes had attained at least 6 months of postoperative follow-up. Five of the 8 eyes achieved an unaided visual acuity of 6/12 or better. Postoperative refractions ranged from -0.50 to -3.50 D of refractive cylinder and from +0.50 to -3.75 D of spherical error. Decentration of the ablation zone was encountered in 3 eyes due to shifts in patients' fixation. Technical difficulty with the use of the hand-held ablatable mask limited the widespread application of this procedure and it has now been superseded by newer excimer laser systems which can correct astigmatism without having to employ a mask. Despite this, because of the theoretical ability of the mask to correct any form of refractive error, the concept of the mask shape transfer process will remain as a potential alternative in refractive surgery, especially for correction of hyperopia and hyperopic astigmatism.

Efficient gene transfer into zebrafish skeletal muscle by intramuscular injection of plasmid DNA

The ability of zebrafish skeletal muscles to internalize and express plasmid DNA was demonstrated using pCMVCAT1, a chloramphenicol acetyltransferase (CAT) construct driven by the human cytomegalovirus immediate early (CMV-IE) promoter. We found that CAT activity was correlated to the amount of plasmid DNA injected, with maximal expression at 5 micrograms of pCMVCAT1. CAT activity was also shown to increase steadily over the first seven days after injection, with high levels of CAT expression persisting up to one year. Intramuscular injection of CAT constructs driven by other viral promoters also resulted in high levels of CAT activity. Histochemical localization using a CMV beta-galactosidase construct confirmed that only myofibers at the site of injection expressed beta-galactosidase enzyme. The persistence and strong expression of injected plasmid constructs suggest that zebrafish may be a simple and readily accessible system for direct muscle injection studies.

Harvesting a lamellar graft from a corneoscleral button: a new technique

PURPOSE

To describe a new technique for harvesting a lamellar graft from a corneoscleral button in the absence of an artificial anterior chamber.

METHODS

Two layers of sterile fine-weave fabric were wrapped tightly around a glass orbital implant. The corneoscleral button was sutured firmly at its scleral rim onto the fabric. The lamellar graft then was dissected in the regular fashion.

RESULTS

The lamellar graft was successfully obtained. During the dissection, the donor cornea and its supporting fabric-covered glass ball were easily handled, and there was minimal risk of perforation of the posterior lamella of the donor cornea.

CONCLUSION

This simple technique allows a lamellar graft to be easily obtained from a corneoscleral button without specialized and expensive equipment.

A phase II study of carboplatin in nasopharyngeal carcinoma

This is a phase II study to evaluate the efficacy and toxicity of short-course carboplatin in advanced-stage nasopharyngeal carcinoma (NPC). Thirty-three previously untreated stage III-IV NPC patients were studied. Carboplatin was given as a rapid intravenous injection every 3 weeks. The dose of carboplatin was calculated according to the individual patient's creatinine clearance and desired platelet nadir of 75,000/microliter according to the Egorin formula. Response and toxicity were evaluated. Thirty-two patients were evaluated for response. The median age was 54 years, range 30-70 years. Twenty-four patients had local regional disease and 8 patients had metastatic disease. The median dose of carboplatin given was 415 mg/m2 (range 91-791 mg/m2). Fourteen (44%) patients had a partial response with a 95% confidence interval of 26-62%. Fifteen (47%) patients had stable disease and 3 (9%) progressive disease. The overall median survival rate was not reached at 43 months. Overall toxicity was tolerable. Grade III-IV myelosuppression occurred in 4 (12%) patients. There were no other major toxicity- or treatment-related deaths. We conclude that carboplatin has a significant anticancer effect in advanced NPC. Thus carboplatin combination chemotherapy for the treatment of NPC is worthy of future clinical investigations.

Phase II study of megestrol acetate in the treatment of hepatocellular carcinoma

This is a report of a phase II study of megestrol acetate (160 mg/day, orally) in the treatment of hepatocellular carcinoma (HCC). Forty-six patients with advanced HCC were studied and tumour response, changes in appetite, bodyweight, a feeling of well-being, survival and toxicity were evaluated. Thirty-two patients were able to be evaluated for response; there were no complete responders or partial responders. Twelve patients (38%) had stable disease and seven of these patients had a minor response with a median size reduction in the tumour of 18%. Twenty patients (62%) had progressive disease. Five of 24 (21%) patients had a median reduction in alpha-fetoprotein levels of 59 ng/mL. The overall median survival was 4 months (range 1 week to 27 months). Twenty of 32 (62%) patients had an increased appetite and feeling of well-being. Fourteen of 22 (64%) patients had a median lean bodyweight gain of 5 kg (range 1-14 kg). Toxicities were minimal. Tests for glucocorticoid receptors were performed in 10 patients. Four of five patients who were positive for glucocorticoid receptors in the tumour had a stable disease and all five patients who were negative for glucocorticoid receptors had progressive disease. Megestrol acetate had no significant effect on the tumour in HCC patients. However, megestrol acetate is useful in the palliative management of HCC patients, with improvements in appetite, bodyweight and a feeling of well-being with minimal side effects. Some patients had stable disease, a minor reduction of tumour size and a prolonged survival after megestrol acetate treatment and this response may be related to the presence of glucocorticoid receptors in the HCC tumour.

Characterization of a subset of the basic-helix-loop-helix-PAS superfamily that interacts with components of the dioxin signaling pathway

In an effort to better understand the mechanism of toxicity of 2,3,7, 8-tetrachlorodibenzo-p-dioxin, we employed an iterative search of human expressed sequence tags to identify novel basic-helix-loop-helix-PAS (bHLH-PAS) proteins that interact with either the Ah receptor (AHR) or the Ah receptor nuclear translocator (ARNT). We characterized five new "members of the PAS superfamily," or MOPs 1-5, that are similar in size and structural organization to the AHR and ARNT. MOPs 1-4 have N-terminal bHLH and PAS domains and C-terminal variable regions. MOP5 contained the characteristic PAS domain and a variable C terminus; it is possible that the cDNA contains a bHLH domain, but the entire open reading frame has yet to be completed. Coimmunoprecipitation studies, yeast two-hybrid analysis, and transient transfection experiments demonstrated that MOP1 and MOP2 dimerize with ARNT and that these complexes are transcriptionally active at defined DNA enhancer sequences in vivo. MOP3 was found to associate with the AHR in vitro but not in vivo. This observation, coupled with the fact that MOP3 formed tighter associations with the 90-kDa heat shock protein than the human AHR, suggests that MOP3 may be a conditionally active bHLH-PAS protein that requires activation by an unknown ligand. The expression profiles of the AHR, MOP1, and MOP2 mRNAs, coupled with the observation that they all share ARNT as a common dimeric partner, suggests that the cellular pathways mediated by MOP1 and MOP2 may influence or respond to the dioxin signaling pathway.