Sequential expression of putative stem cell markers in gastric carcinogenesis

BACKGROUND

Gastric carcinogenesis has been well documented in the step-wise histopathological model, known as Correa pathway. Several biomarkers including CD44, Musashi-1 and CD133 have been reported as putative stem cell (PSC) markers.

METHODS

We investigated expression of PSC markers CD44, Musashi-1 and CD133 in relation to gastric carcinogenesis and prognosis and chemoresponse. Immunohistochemistry staining was performed in gastric cancer (GC) clinical specimens representing different steps of the Correa pathway. Gastric cancer samples taken before and after neoadjuvant chemotherapy with docetaxel, cisplatin and capecitabine (DCX) were also evaluated for PSC marker expression.

RESULTS

We showed that the expression of three PSC markers was significantly elevated in GC relative to normal gastric mucosa (P<0.001 for each marker). Precancerous lesions, including intestinal metaplasia and dysplasia, demonstrated increased expression of CD44 and Musashi-1. CD133 was predominantly expressed along the border between intramucosal carcinoma and connective tissue at later stages. High CD44 and CD133 expression showed prognostic value for worse patient survival (P=0.014 and P=0.019, respectively). A small number of tumours with high expression of CD44 and CD133 showed pathological response to DCX-based neoadjuvant chemotherapy.

CONCLUSION

CD44 and Musashi-1 are frequently expressed in both premalignant gastric lesions and invasive GC, whereas CD133 expression is restricted mainly to neoplastic tissues.

Comparison of Chinese and Western rifapentines and improvement of bioavailability by prior taking of various meals

Bioavailability was measured by rifapentine (RPE) serum concentrations and by the urinary ratio between RPE and creatinine, in specimens obtained 4-50 h after 600 mg RPE preceded by food. The bioavailabilities of RPEs manufactured in China and by a Western manufacturer were similar after a standard English breakfast, and serum concentrations were also similar to those obtained in an earlier Italian study following a complex meal. Although absorption of RPE was unsatisfactory after lipid-rich biscuits or shortbread, absorption after egges and toast was excellent and was nearly as good after a fast-food sandwich. The urinary measure of bioavailability at 26 h appeared as efficient as peak serum estimations at 6, 8 and 26 h. Fast-food sandwiches are being taken before RPE in a current clinical trial of Chinese RPE in Hong Kong.

Multicenter phase II study of gemcitabine and oxaliplatin in advanced nasopharyngeal carcinoma--correlation with excision repair cross-complementing-1 polymorphisms

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a platinum-sensitive cancer and excision repair cross-complementing group 1 (ERCC1) polymorphisms have been shown to predict survival in several cancers following platinum therapy.

PATIENTS AND METHODS

This multicenter study evaluated the activity of oxaliplatin and prolonged infusion of gemcitabine ('GEMOX' regimen) in recurrent NPC. Baseline blood samples were genotyped for the presence of ERCC1-118 gene polymorphisms.

RESULTS

Forty-two patients were recruited, of whom most (61%) had metastatic disease. Of the 40 patients evaluated for response, the respective overall response and disease control rates were 56.1% and 90.2%. At a median follow-up of 14.8 months, the respective median overall survival and time to progression were 19.6 months [95% confidence interval (CI) = 12.8-22 months] and 9 months (95% CI = 7.3-10 months). Grade 3-4 toxic effects were uncommon. The distribution of ERCC1-118 genotypes from 29 patients was C/C (n = 17, 40.5%), C/T (n = 10, 23.8%) and T/T (n = 2, 4.8%). No differences in survival or response rates were found between genotypes.

CONCLUSIONS

GEMOX is active in the treatment of recurrent NPC. Detection of single-nucleotide gene polymorphisms from genomic DNA in peripheral blood is feasible in NPC and further studies are warranted.

A randomized study of aprepitant, ondansetron and dexamethasone for chemotherapy-induced nausea and vomiting in Chinese breast cancer patients receiving moderately emetogenic chemotherapy

OBJECTIVES

This is a single center, randomized, double-blind placebo-controlled study to evaluate the NK(1)-receptor antagonist, aprepitant, in Chinese breast cancer patients. The primary objective was to compare the efficacy of aprepitant-based antiemetic regimen and standard antiemetic regimen for the prevention of chemotherapy-induced nausea and vomiting (CINV) in patients who received moderately emetogenic chemotherapy. The secondary objective was to compare the patient-reported quality of life in these two groups of patients.

PATIENTS AND METHODS

Eligible breast cancer patients were chemotherapy-naive and treated with adjuvant AC chemotherapy (i.e. doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2)). Patients were randomly assigned to either an aprepitant-based regimen (day 1, aprepitant 125 mg, ondansetron 8 mg, and dexamethasone 12 mg before chemotherapy and ondansetron 8 mg 8 h later; days 2 through 3, aprepitant 80 qd) or a control arm which consisted of standard regimen (day 1, ondansetron 8 mg and dexamethasone 20 mg before chemotherapy and ondansetron 8 mg 8 h later; days 2 through 3, ondansetron 8 mg bid). Data on nausea, vomiting, and use of rescue medication were collected with a self-report diary, patients quality of life were assessed by self-administered Functional Living Index-Emesis (FLIE).

RESULTS

Of 127 patients randomized, 124 were assessable. For CINV in Cycle 1 AC, there was no significant difference in the proportion of patients with reported complete response, complete protection, total control, 'no vomiting', 'no significant nausea' and 'no nausea'. The requirement of rescue medication appears to be lesser in patients treated with the aprepitant-based regimen compared to those with the standard regimen (11% vs. 20%; P = 0.06). Assessment of FLIE revealed that while there was no difference in the nausea domain and the total score between the two groups; however, patients receiving standard antiemetic regimen had significantly worse quality of life in the vomiting domain (mean score [SD] = 23.99 [30.79]) when compared with those who received the aprepitant-based regimen (mean score [SD] = 3.40 [13.18]) (P = 0.0002). Both treatments were generally well tolerated. Patients treated with the aprepitant-based regimen had a significantly lower incidence of neutropenia (53.2% vs. 35.5%, P = 0.0468), grade >or= 3 neutropenia (21.0% vs. 45.2, P = 0.0042) and delay in subsequent cycle of chemotherapy (8.1% vs. 27.4%, P = 0.0048).

CONCLUSION

The aprepitant regimen appears to reduce the requirement of rescue medication when compared with the control regimen for prevention of CINV in patients receiving both an anthracycline and cyclophosphamide, and is associated with a better quality of life during adjuvant AC chemotherapy.

Exploring ligand recognition and ion flow in comparative models of the human GABA type A receptor

We present two comparative models of the GABA(A) receptor. Model 1 is based on the 4-A resolution structure of the nicotinic acetylcholine receptor from Torpedo marmorata and represents the unliganded receptor. Two agonists, GABA and muscimol, two benzodiazepines, flunitrazepam and alprazolam, together with the general anaesthetic halothane, have been docked to this model. The ion flow is also explored in model 1 by evaluating the interaction energy of a chloride ion as it traverses the extracellular, transmembrane and intracellular domains of the protein. Model 2 differs from model 1 only in the extracellular domain and represents the liganded receptor. Comparison between the two models not only allows us to explore commonalities and differences with comparative models of the nicotinic acetylcholine receptor, but also suggests possible protein sub-domain interactions with the GABA(A) receptor not previously addressed.

Regulation of p53 and suppression of apoptosis by the soluble guanylyl cyclase/cGMP pathway in human ovarian cancer cells

Dysregulated apoptosis plays a critical role in the development of a number of aberrant cellular processes, including tumorigenesis and chemoresistance. However, the mechanisms that govern the normal apoptotic program are not completely understood. Soluble guanylyl cyclase (sGC) and cyclic guanosine monophosphate (cGMP) promote mammalian cell viability via an unknown mechanism and p53 status is a key determinant of cell fate in human ovarian cancer cells. Whether an interaction exists between these two determinants of cell fate is unknown. We hypothesized that basal sGC activity reduces p53 content and attenuates p53-dependent apoptosis in human ovarian cancer cells. Suppression of sGC activity with the specific inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) lowered cGMP content, and increased p53 protein content and induced apoptosis in three ovarian cancer cell lines, effects which were attenuated by the cGMP analog 8-Br-cGMP and by Atrial Natriuretic Factor, an activator of particulate guanylyl cyclase, which circumvent the inhibition of sGC. ODQ prolonged p53 half-life, induced phosphorylation of p53 on Ser15, and upregulated the p53-dependent gene products p21, murine double minute-2, and the proapoptotic, p53-responsive gene product Bax. ODQ activated caspase-3, and ODQ-induced apoptosis was inhibited by overexpression of X-linked inhibitor of apoptosis Protein. Pretreatment with the specific p53 inhibitor pifithrin or downregulation of p53 using a specific small inhibitory RNA significantly attenuated ODQ-induced apoptosis. Moreover, ODQ-induced upregulation of p21 and Bax and ODQ-induced apoptosis were significantly reduced in a p53 mutant cell line relative to the wild-type parental cell line. Thus, the current study establishes that basal sGC/cGMP activity regulates p53 protein stability, content, and function, possibly by altering p53 phosphorylation and stabilization, and promotes cell survival in part through regulation of caspase-3 and p53.

Unbinding pathways of an agonist and an antagonist from the 5-HT3 receptor

The binding sites of 5-HT3 and other Cys-loop receptors have been extensively studied, but there are no data on the entry and exit routes of ligands for these sites. Here we have used molecular dynamics simulations to predict the pathway for agonists and antagonists exiting from the 5-HT3 receptor binding site. The data suggest that the unbinding pathway follows a tunnel at the interface of two subunits, which is approximately 8 A long and terminates approximately 20 A above the membrane. The exit routes for an agonist (5-HT) and an antagonist (granisetron) were similar, with trajectories toward the membrane and outward from the ligand binding site. 5-HT appears to form many hydrogen bonds with residues in the unbinding pathway, and experiments show that mutating these residues significantly affects function. The location of the pathway is also supported by docking studies of granisetron, which show a potential binding site for granisetron on the unbinding route. We propose that leaving the binding pocket along this tunnel places the ligands close to the membrane and prevents their immediate reentry into the binding pocket. We anticipate similar exit pathways for other members of the Cys-loop receptor family.

Animal model for the pathogenesis of reactive amyloidosis

The pathogenesis of amyloidosis is not well understood. Here, Zafer Ali-Khan, Weihua Li and Sic L. Chan present a metazoan parasite mouse model of reactive amyloidosis, review the relationship between chronic inflammation and multiorgan AA amyloidosis and postulate how ubiquitin might function in the processing of serum amyloid A and in AA amyloid formation in the endosomes-lysosomes of activated murine reticuloendothetial cells.

Appropriateness of the use of parenteral nutrition in a local tertiary-care hospital

INTRODUCTION

Parenteral nutrition (PN) is an important supportive therapy for critically ill patients who have non-functioning gut. However, it is an expensive therapy and carries significant complications. The objective of our audit was to determine the appropriateness of prescription of PN in our hospital, based on the American Society for Parenteral and Enteral Nutrition (ASPEN) 2002 guidelines. In our hospital, the prescription of PN is managed by the Nutrition Support Team.

MATERIALS AND METHODS

A retrospective review of adult patients prescribed with PN in 2001 was undertaken. Data on patient demographics, underlying diagnoses, indications, duration and routes administration were collected. The use of PN was classified as "appropriate", "inappropriate" or "indeterminate" by the authors based on the above guidelines.

RESULTS

145 patients were prescribed PN in 2002. We were able to review the case notes for 137 patients. One patient received PN on 2 separate admissions. Of the 138 courses of PN (in 137 patients) reviewed, there were 88 males with the median age of 61 years (range, 16 to 91 years). 81.2% were surgical patients and of the remaining patients, 10.1% had haematological malignancies. The 2 most common indications were postoperative ileus (37.0%) and post-surgical complications (14.5%). The median duration of PN prescription was 9 days (range, 1 to 175 days). 109 (78.3%) courses of PN were classified as "appropriate", 22 (15.9%) courses as "inappropriate" and 7 (5.8%) courses as "indeterminate". Patients from the postoperative ileus group contributed to 10 (45.5%) patients with "inappropriate" indications; the main reason was premature initiation of PN. Of the patients considered to show "inappropriate" indications, 15 courses (68.1%) were prescribed for less than 7 days. PN was discontinued in 78% of courses due to satisfactory resumption of oral or enteral intake. The mean duration of PN use for patients with "inappropriate" indication was significantly shorter than for patients with "appropriate" indication (7.7 +/- 5.3 days versus 15.8 +/- 20.0 days, P = 0.002). 99.3% of PN courses were given via the central routes (with central vein cannulation or PICC). These lines were specifically inserted for PN in 60.14% of the cases.

CONCLUSION

Our audit showed that 15.9% of PN prescriptions were inappropriate according to the ASPEN guidelines. This was largely attributed to premature initiation of PN for postoperative ileus. We believe that these PN courses could have been avoided if these patients had been tried on naso-jejunal tube feeding, or oral nutrition with the use of prokinetics during the postoperative period.

Evidence for Nonadrenoceptor Responses to Imidazoline Derivatives in the Porcine Isolated Rectal Artery

High concentrations of phentolamine, efaroxan, and idazoxan were found to produce nonadrenoceptor contractions of the porcine isolated rectal artery previously exposed to U46619 and forskolin. These responses were insensitive to the putative imidazoline I(3) receptor antagonist KU-14R, unlike those previously reported in this preparation for oxymetazoline. The pharmacologic nature of this response and the obligate requirement for preconstriction suggests that these imidazoline derivatives modulate ion channel function through a novel nonadrenergic site.

Prevalence and predictors of default from tuberculosis treatment in Hong Kong

OBJECTIVE

To determine the prevalence and risk factors of default from tuberculosis treatment in Hong Kong.

DESIGN

Retrospective study.

SETTING

Data were obtained from programme forms completed by physicians in the Hong Kong Government Tuberculosis and Chest Service and from medical records from Hong Kong chest clinics.

PATIENTS

In all, 5917 patients registered for antituberculous drug therapy in 1996; medical records of 5757 patients were reviewed.

MAIN OUTCOME MEASURES

Patients who defaulted treatment were defined as those who had failed to collect medication for more than 2 consecutive months after the date of the last attendance during the course of treatment. Demographic and clinical characteristics, including history, treatment, and outcome, were compared between defaulters and non-defaulters, both among the whole group and among those with pulmonary disease.

RESULTS

There were 442 (8%) patients who defaulted from treatment. Forty-five percent of those who defaulted did so in the first 2 months of treatment. Key risk factors associated with non-compliance were a history of default, male sex, and a history of concomitant liver disease or lung cancer. Among patients with pulmonary tuberculosis (381 defaulters and 1537 non-defaulters), multiple drug resistance was also associated with default from treatment. Among defaulters with pulmonary disease, 39% were still bacteriologically positive at the time of default.

CONCLUSION

Default from treatment may be partially responsible for the persistent high rates of tuberculosis in Hong Kong in the past decade. Health professionals should ensure that all barriers to treatment be removed and that incentives be used to encourage treatment compliance.

Tuberculosis in Hong Kong-patient characteristics and treatment outcome

OBJECTIVES

To identify the general characteristics of patients with tuberculosis, and to evaluate their treatment outcomes.

DESIGN

Retrospective study.

SETTING

Tuberculosis and Chest Service, Department of Health, Hong Kong.

SUBJECTS AND METHODS

All patients with tuberculosis registered for treatment from 1 January 1996 to 31 December 1996 were included in the study. Information was extracted from their medical records at treatment commencement and at 12 and 24 months after treatment was instigated. Data gathered included demographic data, past treatment, site of disease, case category, treatment regimen, bacteriological status, and treatment outcome.

RESULTS

There were 5757 patients for analysis. Approximately one third of patients were aged 60 years or older, and 69.1% were male. Pulmonary disease alone occurred in 77.7% of patients, while both pulmonary and extrapulmonary diseases occurred in 8.6%. New patients comprised 84.6% of cases, and 16.3% had concomitant illnesses. There was excess risk of disease among patients who were male, elderly, or who had silicosis. Only 0.1% of patients were co-infected with human immunodeficiency virus infection. Among the 5757 cases evaluated, 1324 (23.0%) were new patients with a positive sputum smear, 299 (5.2%) were patients who were retreated with a positive sputum smear, and 4134 (71.8%) were new or retreatment patients with a negative sputum smear. The overall treatment completion rates at 12 and 24 months were 80.4% and 84.8%, respectively. Males and patients aged 60 years or older had lower treatment completion rates. Non-adherence, transfer to other services, and mortality among the elderly were key factors influencing treatment outcomes. Co-morbidity was associated with better case-holding, and this more than compensated for its effect on prolongation of treatment and mortality.

CONCLUSIONS

There was an excess risk of tuberculosis among male and elderly patients, who also had a less favourable outcome. Active screening of clearly identified risk groups may be appropriate but requires the completion of more in-depth studies and careful cost-effectiveness analyses. Further efforts with respect to case-holding are indicated to address treatment defaulting and transfer rates.

Extra-pulmonary and pulmonary tuberculosis in Hong Kong

OBJECTIVE

To compare the characteristics of patients with pulmonary and extra-pulmonary tuberculosis and to describe the organ involvement, diagnosis and treatment of extra-pulmonary tuberculosis.

MATERIALS AND METHODS

All patients with a diagnosis of tuberculosis treated by the Hong Kong Government Tuberculosis and Chest Service (Chest Service) in 1996 were studied.

RESULTS

Of the 5757 patients treated, 13.7% had extra-pulmonary tuberculosis alone and 8.6% had both extra-pulmonary tuberculosis and pulmonary tuberculosis. Extra-pulmonary tuberculosis was more common in women under 30 and over 75 years of age. Only six patients had human immunodeficiency virus (HIV) infection, of whom two had extra-pulmonary tuberculosis. The most common site of extra-pulmonary involvement was the pleura, followed by the lymph nodes. Miliary tuberculosis occurred in only 2.9%. Lymph node involvement occurred significantly higher in women, while pleural disease was significantly higher in men. The duration of treatment varied according to the site of disease, being shorter (6 months) for those with pleural disease only and >9 months for those with miliary, meningeal, gastrointestinal and genitourinary disease; 80.3% completed treatment at 12 months and 85.5% at 24 months. Of those who completed treatment, 1.4% had a relapse of disease at 24 months follow-up; there was no significant difference between those with pulmonary or extra-pulmonary disease.

CONCLUSION

In Hong Kong, extra-pulmonary tuberculosis is common, affecting 22.3% of TB patients, and is unrelated to HIV infection. There are sex differences in the organs most commonly affected. The rate of relapse of disease is low for those who completed treatment, irrespective of the site of involvement.

Tuberculosis in the elderly in Hong Kong

BACKGROUND

The rate of tuberculosis in Hong Kong has declined dramatically since the 1950s, but has remained high during the past decade, at around 110/100,000. The reason for the persistent high rate is not clear.

OBJECTIVES

To study the trend of tuberculosis in Hong Kong during the past decade (1989 to 1998) and the clinical characteristics of tuberculosis patients > or = 60 years of age, and compare them with those of the younger age groups.

METHODS

Notification rates of tuberculosis from 1989 to 1998 were obtained from the Hong Kong Government Tuberculosis and Chest Service (Chest Service), Department of Health, Hong Kong. In addition, all patients registered at the Chest Service for treatment of tuberculosis in 1996 were studied.

RESULTS

During the past decade, the notification rate of tuberculosis, which included both bacteriologically confirmed and clinically active but bacteriologically not confirmed cases, decreased in those under 60, remained unchanged in those between 60-69, and increased in those > or = 70 years of age. An increase in the rate of bacteriologically confirmed cases (sputum smear or culture positive for Mycobacterium tuberculosis) in the older age groups was observed during the same period. In 1989, 31.9% of tuberculosis cases were over the age of 60 years; this proportion increased to 45.4% in 1998. The increase in the number of cases in those > or = 60 years could almost account for the total increase in number of cases during the last decade. Patients in the older age groups had more advanced disease at the time of diagnosis, and a higher proportion had comorbid illnesses. They also had significantly higher mortality compared with the younger age groups.

CONCLUSION

The increasing longevity of the population and the high rate of tuberculosis in the elderly are important factors contributing to the persistent high rate of tuberculosis in Hong Kong in the past decade.

Exhaled nitric oxide: the effects of age, gender and body size

Since little is known of the effects of age, gender, and body size on exhaled nitric oxide (NO) production, we have conducted a prospective study to examine these factors in a healthy nonsmoking women (mean age +/- SD 47.7 +/- 15.8, range 20-79 years). Exhaled NO was measured by an automatic chemiluminescence analyzer (Sievers NO Analyser 280) at steady expiration. Men had significantly higher exhaled NO levels than women (p = 0.001). Although exhaled NO levels did not correlate with age (r = 0.12, p = 0.17), it correlated significantly with height (r = 0.23, p = 0.02), weight (r = 0.34, p

Perturbed endoplasmic reticulum function, synaptic apoptosis and the pathogenesis of Alzheimer's disease

Endoplasmic reticulum (ER) appears to be a focal point for alterations that result in neuronal dysfunction and death in Alzheimer's disease (AD). Aberrant proteolytic processing and/or trafficking of the beta-amyloid precursor protein (APP) in ER may promote neuronal degeneration by increasing the levels of the neurotoxic forms of beta-amyloid (A beta) and by decreasing the levels of the neuroprotective secreted form of APP (sAPP alpha). Some cases of AD are caused by mutations in the genes encoding presenilin 1 (PS1). When expressed in cultured neuronal cells and transgenic mice, PS1 mutations cause abnormalities in ER calcium homoeostasis, enhancing the calcium responses to stimuli that activate IP3- and ryanodine-sensitive ER calcium pools. Two major consequences of this disrupted ER calcium regulation are altered proteolytic processing of APP and increased vulnerability of neurons to apoptosis and excitotoxicity. The impact of PS1 mutations and aberrant APP processing is particularly great in synaptic terminals. Perturbed synaptic calcium homoeostasis promotes activation of apoptotic cascades involving production of Par-4 (prostate apoptosis response-4), mitochondrial dysfunction and caspase activation. A beta 42 (the 42-amino-acid form of A beta) induces membrane lipid peroxidation in synapses and dendrites resulting in impairment of membrane ion-motive ATPases and glucose and glutamate transporters. This disrupts synaptic ion and energy homoeostasis thereby promoting synaptic degeneration. In contrast, sAPP alpha activates signalling pathways that protect synapses against excitotoxicity and apoptosis. In the more common sporadic forms of AD, the initiating causes of the neurodegenerative cascade are less well defined, but probably involve increased levels of oxidative stress and impaired energy metabolism. Such alterations have been shown to disrupt neuronal calcium homoeostasis in experimental models, and may therefore feed into the same neurodegenerative cascade initiated by mutations in presenilins and APP. Perturbed synaptic ER calcium homoeostasis and consequent alterations in APP processing appear to be pivotal events in both sporadic and familial forms of AD.

Rifapentine and isoniazid in the continuation phase of a 6-month regimen. Final report at 5 years: prognostic value of various measures

SETTING

Clinical trial in 672 patients with newly diagnosed pulmonary tuberculosis in Hong Kong. After an initial 2 months of a four-drug intensive phase consisting of thrice-weekly streptomycin, isoniazid, rifampicin and pyrazinamide (SHRZ), a random allocation was made to a continuation phase of once-weekly 600 mg rifapentine + 15 mg/kg isoniazid (HRp1), HRp1 given in 2 of every 3 weeks (HRp1.2/3), or to thrice-weekly isoniazid + rifampicin (HR3), the standard treatment in Hong Kong.

OBJECTIVE

Final report evaluating adverse events (46 relapses and one failure) after 5 years and the prognostic influence of various factors.

METHODS

Kaplan-Meier analysis of adverse events and Cox proportional hazards analysis of prognostic factors.

RESULTS

The two rifapentine regimens, HRp1 and HRp1.2/3 had similar final rates of adverse events of 10.8% and 11.7%, respectively, compared to 4.2% for the HR3 regimen (P = 0.02 and 0.009, respectively). In the initial univariate proportional hazards analysis, adverse events were significantly related to the regimen, age, sex, pretreatment radiographic extent of disease and cavitation, and also to sputum culture at 2 months. In the final multivariate analysis, after step-wise removal of non-significant factors, adverse events were related only to the regimen, patients' sex and pretreatment radiographic extent of disease. Elderly male patients were more at risk of an adverse event, as were those with more severe disease. Adverse events occurred at life table rates of 9.0% in patients with drug-sensitive strains and in 8.9% of those with initially isoniazid-resistant organisms at 5 years.

CONCLUSIONS

The two rifapentine regimens were unsatisfactory because of their high incidence of adverse events. Isoniazid appeared not to contribute to preventing relapse. Further studies with increased rifapentine dosage are necessary.

Sex differences in tuberculosis in Hong Kong

SETTING

The Hong Kong Tuberculosis and Chest Service, Department of Health, Hong Kong.

OBJECTIVE

To examine sex differences in the rate and clinical manifestations of tuberculosis in Hong Kong.

DESIGN

Notification rates of tuberculosis during the past five decades were obtained from the Hong Kong Tuberculosis and Chest Service, Department of Health, Hong Kong. In addition, all patients registered with the Chest Service for treatment of tuberculosis in 1996 were studied.

RESULTS

The rate of tuberculosis during the past five decades was consistently higher in men than in women, irrespective of age group. The sex difference in rates was highest among those aged over 60 years. In 1996, a higher proportion of women had extra-pulmonary tuberculosis than men; the main site of involvement was the lymph nodes. More women completed treatment at 12 months and fewer women missed treatment appointments. A higher proportion of men had relapse pulmonary disease that was more extensive, a history of previous default from treatment and co-morbid illnesses.

CONCLUSION

There are sex differences in the rates and clinical manifestations of tuberculosis in Hong Kong. Study of sex differences is essential for targeting prevention programmes at groups at higher risk.

Contact examination for tuberculosis in Hong Kong is useful

SETTING

The tuberculosis programme of the Hong Kong Government Tuberculosis and Chest Service.

OBJECTIVE

To determine the outcome of examination of household contacts in Hong Kong.

DESIGN

A retrospective cohort study of all household contacts of 970 randomly selected index cases from a total of 5757 registered for treatment with the Chest Service.

RESULTS

Of 2678 household contacts (three/index case) identified, 90% were examined; 41 active cases were found, at a rate of 1720/100000 (95%CI 1238-2329). The rate was highest among two extremes of age, 3604/100000 (95%CI 990-3615) in children < or = 5 years and 3347/100000 (95%CI 1456-6489) in those >60 years of age. Contacts of index cases whose sputum smear and culture were positive had the highest rate of disease, 2904/100000 (95%CI 1669-4673); but contacts with negative bacteriology also had a high rate of 1478/100000 (95%CI 678-2789). Active cases identified through contact tracing could be source cases rather than secondary cases. Eight per cent of children aged < or = 5 years had positive tuberculin reactions; as BCG vaccination is given to all newborns, with 99% coverage in Hong Kong in the past 30 years, it was difficult to estimate the rate of infection in these children.

CONCLUSION

In Hong Kong, an area with an intermediate burden of tuberculosis, contact investigation is a very useful procedure for active case finding.

The Caenorhabditis elegans sex-determining protein FEM-2 and its human homologue, hFEM-2, are Ca2+/calmodulin-dependent protein kinase phosphatases that promote apoptosis

In Caenorhabditis elegans, fem-1, fem-2, and fem-3 play pivotal roles in sex determination. Recently, a mammalian homologue of the C. elegans sex-determining protein FEM-1, F1Aalpha, has been described. Although there is little evidence to link F1Aalpha to sex determination, F1Aalpha and FEM-1 both promote apoptosis in mammalian cells. Here we report the identification and characterization of a human homologue of the C. elegans sex-determining protein FEM-2, hFEM-2. Similar to FEM-2, hFEM-2 exhibited PP2C phosphatase activity and associated with FEM-3. hFEM-2 shows striking similarity (79% amino acid identity) to rat Ca(2+)/calmodulin (CaM)-dependent protein kinase phosphatase (rCaMKPase). hFEM-2 and FEM-2, but not PP2Calpha, were demonstrated to dephosphorylate CaM kinase II efficiently in vitro, suggesting that hFEM-2 and FEM-2 are specific phosphatases for CaM kinase. Furthermore, hFEM-2 and FEM-2 associated with F1Aalpha and FEM-1 respectively. Overexpression of hFEM-2, FEM-2, or rCaMKPase all mediated apoptosis in mammalian cells. The catalytically active, but not the inactive, forms of hFEM-2 induced caspase-dependent apoptosis, which was blocked by Bcl-XL or a dominant negative mutant of caspase-9. Taken together, our data suggest that hFEM-2 and rCaMKPase are mammalian homologues of FEM-2 and they are evolutionarily conserved CaM kinase phosphatases that may have a role in apoptosis signaling.

p38 MAP kinase mediates nitric oxide-induced apoptosis of neural progenitor cells

Neural progenitor cells (NPC) can proliferate, differentiate into neurons or glial cells, or undergo a form of programmed cell death called apoptosis. Although death of NPC occurs during development of the nervous system and in the adult, the underlying mechanisms are unknown. Here we show that nitric oxide (NO) can induce death of C17.2 NPC by a mechanism requiring activation of p38 MAP kinase, poly(ADP-ribose) polymerase, and caspase-3. Nitric oxide causes release of cytochrome c from mitochondria, and Bcl-2 protects the neural progenitor cells against nitric oxide-induced death, consistent with a pivotal role for mitochondrial changes in controlling the cell death process. Inhibition of p38 MAP kinase by SB203580 abolished NO-induced cell death, cytochrome c release, and activation of caspase-3, indicating that p38 activation serves as an upstream mediator in the cell death process. The anti-apoptotic protein Bcl-2 protected NPC against nitric oxide-induced apoptosis and suppressed activation of p38 MAP kinase. The ability of nitric oxide to trigger death of NPC by a mechanism involving p38 MAP kinase suggests that this diffusible gas may regulate NPC fate in physiological and pathological settings in which NO is produced.

Vasorelaxant response to isoprenaline, nitric oxide donor, calcitonin gene-related peptide and vasoactive intestinal peptide in aortic rings of adult C57BL/6J mice

The mouse and tissues from this species are increasingly used as experimental models because of the wide variety of gene deletions and overexpressions available in this species. Yet, very little is known about normal vascular responses in the mouse. We investigated the vasorelaxant responses on thoracic aortic rings from the adult male C57BL/6J mouse. Isoprenaline, acetylcholine, calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and sodium nitroprusside all caused concentration-dependent relaxations in aortic rings possessing healthy endothelium and precontracted with phenylephrine. Maximum relaxations were 64.9+/-2.6%, 66.8+/-2.9%, 114.3+/-4.6%, 65.1+/-4.2% and 116.2+/-5.1% with -logEC(50) values of 6.76+/-0.14, 7.04+/-0.11, 8.53+/-0.14, 8.29+/-0.26 and 8.10+/-0.20 for isoprenaline, acetylcholine, CGRP, VIP and sodium nitroprusside, respectively. There were significantly smaller responses to isoprenaline, acetylcholine, CGRP and VIP when the endothelium was denuded. The maximum relaxations for isoprenaline, CGRP and acetylcholine were 48.3+/-5.1%, 99.6+/-4.4% and 5.7+/-1.6% with -logEC(50) values of 6.44+/-0.40 and 8.23+/-0.192, respectively, following endothelium removal. The response to VIP was completely dependent to endothelium. Without precontraction, isoprenaline, at the higher doses, caused small contractions. These experiments provide new information about vascular responses of five vasodilators in aortic rings of adult male C57BL/6J mice.