Shape-control growth of 2D-In2Se3 with out-of-plane ferroelectricity by chemical vapor deposition

For potential applications in ferroelectric switching and piezoelectric nano-generator devices, the promising ferroelectric properties of two dimensional (2D) layered In2Se3 attracted much attention. In the present study, 2D In2Se3 flakes down to monolayers are grown by the chemical vapor deposition (CVD) technique on a mica substrate with their structural, optical and ferroelectric properties being studied. The effect of growth parameters (time of growth and Ar flow rate) on the shape and size of the deposited flakes was studied. The optical microscopy study revealed that the flake changed from a circular shape to a sharp face triangle as the Ar flow rate and growth time increased. Raman spectroscopy and high-resolution scanning transmission electron microscopy (HR-STEM) studies revealed that the flakes were of α and β phases, each of which has a hexagonal crystal structure. Strong second harmonic generation (SHG) was observed from α-In2Se3, demonstrating its non-centrosymmetric structure. The piezo-force microscopic (PFM) study showed the presence of out of plane (OOP) ferroelectricity with no in plane (IP) ferroelectricity in CVD grown α-In2Se3 indicating its vertically confined piezoresponse, which was tuned by the applied electric bias and the flake thickness. The present result of shape-controlled growth of In2Se3 with OOP ferroelectricity would open new pathways in the field of 2D ferroelectric switching devices.

Lipophilic activated ester prodrug approach for drug delivery to the intestinal lymphatic system

The intestinal lymphatic system plays an important role in the pathophysiology of multiple diseases including lymphomas, cancer metastasis, autoimmune diseases, and human immunodeficiency virus (HIV) infection. It is thus an important compartment for delivery of drugs in order to treat diseases associated with the lymphatic system. Lipophilic prodrug approaches have been used in the past to take advantage of the intestinal lymphatic transport processes to deliver drugs to the intestinal lymphatics. Most of the approaches previously adopted were based on very bulky prodrug moieties such as those mimicking triglycerides (TG). We now report a study in which a lipophilic prodrug approach was used to efficiently deliver bexarotene (BEX) and retinoic acid (RA) to the intestinal lymphatic system using activated ester prodrugs. A range of carboxylic ester prodrugs of BEX were designed and synthesised and all of the esters showed improved association with chylomicrons, which indicated an improved potential for delivery to the intestinal lymphatic system. The conversion rate of the prodrugs to BEX was the main determinant in delivery of BEX to the intestinal lymphatics, and activated ester prodrugs were prepared to enhance the conversion rate. As a result, an 4-(hydroxymethyl)-1,3-dioxol-2-one ester prodrug of BEX was able to increase the exposure of the mesenteric lymph nodes (MLNs) to BEX 17-fold compared to when BEX itself was administered. The activated ester prodrug approach was also applied to another drug, RA, where the exposure of the MLNs was increased 2.4-fold through the application of a similar cyclic activated prodrug. Synergism between BEX and RA was also demonstrated in vitro by cell growth inhibition assays using lymphoma cell lines. In conclusion, the activated ester prodrug approach results in efficient delivery of drugs to the intestinal lymphatic system, which could benefit patients affected by a large number of pathological conditions.

Outcome Predictors of Patients in Out-Of-Hospital Cardiac Arrests with Pre-Hospital Defibrillation in Hong Kong

Objective

To report the epidemiology, outcomes and the predictors of survival in patients with out-of-hospital cardiac arrest (OHCA) with pre-hospital shockable cardiac rhythms in Hong Kong.

Methods

It was a prospective study based on data from the cardiac arrest registry of emergency departments (ED) in two regional hospitals in Hong Kong from 1st August 2010 to 31st January 2012. All non-traumatic patients aged 18 years or above presented with OHCA with shockable pre-hospital cardiac rhythm and received pre-hospital defibrillation were included. The characteristics of patients, pre-hospital data, management and outcomes were recorded in a standardised form compatible with Utstein template at the time of patient consultation. Binominal logistic regression was applied to evaluate the relationship between survival to admission (STA) and patients' variables.

Results

A total of 135 patients fulfilled the inclusion criteria. The mean age was 67.0 years old. The STA rate was 34.8% and the survival to discharge (STD) rate was 6.7%. Factors independently associated with better prognosis in terms of STA were presence of bystander cardiopulmonary resuscitation (CPR) (OR 5.76, 95% CI=1.08-30.5), restoration of spontaneous circulation (ROSC) before arrival to ED (OR 43.94, 95% CI= 4.19-460.43) and short time from calling emergency medical services (EMS) to first defibrillation (OR 0.82, 95% CI=0.70-0.96).

Conclusion

STA rate for adults presenting with shockable OHCA in our study was 34.8%. Patients with shockable OHCA with bystander CPR, short call-to-shock time and achieved ROSC before arrival to ED are significantly associated with higher STA rate.

Green tea polyphenols as proteasome inhibitors: implication in chemoprevention

Next to water, tea is the most popular beverage in the world. The most abundant and active compound in green tea is (-)-epigallocatechin-3-gallate (EGCG), which is extensively studied for its cancer-preventive and anti-cancer activities as well as its cellular targets. One potential molecular target of EGCG is the proteasome. While molecular docking and structure-activity relationship (SAR) analysis suggests that the ester carbon of EGCG is important for mediating its proteasome-inhibitory activity, EGCG is very unstable under physiological conditions. Therefore, a series of analogs were synthesized aiming to improve stability and bioavailability of EGCG. Among them, peracetate-protected or the prodrug of EGCG was found to have increased bioavailability, stability, and proteasome-inhibitory activities against various human cancer cells and tumors compared to EGCG, suggesting its potential use for cancer prevention and treatment. Epidemiological studies have indicated that green tea consumption is associated with the reduced risk of cancers, especially associated with the reduced risk of late stage of cancers. This risk reduction may be attributed not only to proteasome inhibition, but also to numerous other intracellular molecules targeted by EGCG that are involved in cell cycle regulation, apoptosis, angiogenesis, and metastasis.

Green tea polyphenols as a natural tumour cell proteasome inhibitor

The cancer-preventive effects of green tea and its main constituent (-)-epigallocatechin gallate [(-)-EGCG] are widely supported by results from epidemiological, cell culture, animal and clinical studies although the molecular target has not been well defined. We previously reported that ester bond-containing tea polyphenols, e. g. (-)-EGCG, and their synthetic analogs potently and specifically inhibited the proteasomal activity. Subsequently, we further demonstrated that methylation on green tea polyphenols under physiological conditions decreased their proteasome-inhibitory activity, contributing to decreased cancer-preventive effects of tea consumption. Since (-)-EGCG is unstable under physiological conditions, we also developed the peracetate-protected or prodrug form of (-)-EGCG, Pro-EGCG (1), and shown that Pro-EGCG (1) increases the bioavailability, stability, and proteasome-inhibitory and anticancer activities of (-)-EGCG in human breast cancer cells and xenografts, suggesting its potential use for cancer prevention and treatment.

Tea polyphenols, their biological effects and potential molecular targets

Tea is the most popular beverage in the world, second only to water. Tea contains an infusion of the leaves from the Camellia sinensis plant rich in polyphenolic compounds known as catechins, the most abundant of which is (-)-EGCG. Although tea has been consumed for centuries, it has only recently been studied extensively as a health-promoting beverage that may act to prevent a number of chronic diseases and cancers. The results of several investigations indicate that green tea consumption may be of modest benefit in reducing the plasma concentration of cholesterol and preventing atherosclerosis. Additionally, the cancer-preventive effects of green tea are widely supported by results from epidemiological, cell culture, animal and clinical studies. In vitro cell culture studies show that tea polyphenols potently induce apoptotic cell death and cell cycle arrest in tumor cells but not in their normal cell counterparts. Green tea polyphenols were shown to affect several biological pathways, including growth factor-mediated pathway, the mitogen-activated protein (MAP) kinase-dependent pathway, and ubiquitin/proteasome degradation pathways. Various animal studies have revealed that treatment with green tea inhibits tumor incidence and multiplicity in different organ sites such as skin, lung, liver, stomach, mammary gland and colon. Recently, phase I and II clinical trials have been conducted to explore the anticancer effects of green tea in humans. A major challenge of cancer prevention is to integrate new molecular findings into clinical practice. Therefore, identification of more molecular targets and biomarkers for tea polyphenols is essential for improving the design of green tea trials and will greatly assist in a better understanding of the mechanisms underlying its anti-cancer activity.

Appropriateness of colonoscopy using the ASGE guidelines: experience in a large Asian hospital

BACKGROUND

The is currently a heavy burden on endoscopy services worldwide and although guidelines for the appropriate use of esophagogastroduodenoscopy (EGD) have been well studied, there are few such studies with respect to colonoscopy and none for the Asia-Pacific region. This study aimed, firstly, to determine the 'appropriateness of colonoscopy' for procedures performed in the endoscopy unit of a large Asian hospital using the American Society of Gastrointestinal Endoscopy (ASGE) 2000 guidelines, and secondly, to determine predictive factors including 'appropriateness of colonoscopy' for positive findings and colorectal cancer (CRC).

METHODS

A prospective cross-sectional study was carried out on consecutive colonoscopies performed in the University of Malaya Medical Center. The unit has an open-access endoscopy policy for doctors who work in the hospital. Referrals were from endoscopists (gastroenterologists and surgeon-endoscopists), primary care physicians and other specialists. The indication of a procedure referral was recorded and judged 'appropriate' or 'inappropriate' using the ASGE criteria. The colonoscopic findings were recorded and classified as positive (endoscopies showing any pathology that had direct therapeutic or prognostic consequences) or negative findings (endoscopies showing no pathology or minor pathologies). Predictive factors for positive findings and CRC were determined using multivariate analysis.

RESULTS

Of 380 patients referred for colonoscopy, 220 (57.9%) were classified as appropriate according to the ASGE guidelines, and 49 (12.9%) as inappropriate. The remaining 111 patients (29.2%) presented with complaints and conditions that could not be categorized. The rate of appropriate referral was similar for all three categories of physician (endoscopists: 59.8%, primary care physicians: 48.1%, others: 51.1%). When referrals by endoscopists were substratified according to gastroenterologists and surgeon-endoscopists, the rate of appropriate referral among gastroenterologists (78.4%) was significantly higher than that of surgeon-endoscopists (56.1%) (P = 0.049), primary care physicians (P = 0.013) and 'others' (P = 0.009). The most common appropriate indications were unexplained Rectalbleeding (79 cases, 20.8%) followed by CRC surveillance (45 cases, 11.8%). The most common inappropriate indication was inappropriately timed colonic cancer surveillance (32 cases, 8.4%). Chronic constipation in 36 cases (9.5%) was the most common 'unlisted' indication. A positive colonoscopic finding was detected in 131 (34.5%) examinations and CRC was found in 36 patients (9.5%). Appropriateness of indication was not a predictive factor for positive findings or CRC and there was no difference in the proportion of cases with positive findings or CRC in the three 'appropriateness categories'. Multivariate analysis revealed that only Rectalbleeding and smoking were significant independent positive predictive factors for positive findings and CRC.

CONCLUSION

The appropriateness of colonoscopy was not high among the different sources of referrals except for the subgroup of 'gastroenterologist'. Furthermore, the rates of positive findings and CRC among the cases with appropriate, inappropriate and unlisted indications did not differ. The ASGE guidelines will need to be modified for Asia to be of practical use.

Multiresolution wavelet analysis for efficient analysis, compression and remote display of long-term physiological signals

Increased inter-equipment connectivity coupled with advances in Web technology allows ever escalating amounts of physiological data to be produced, far too much to be displayed adequately on a single computer screen. The consequence is that large quantities of insignificant data will be transmitted and reviewed. This carries an increased risk of overlooking vitally important transients. This paper describes a technique to provide an integrated solution based on a single algorithm for the efficient analysis, compression and remote display of long-term physiological signals with infrequent short duration, yet vital events, to effect a reduction in data transmission and display cluttering and to facilitate reliable data interpretation. The algorithm analyses data at the server end and flags significant events. It produces a compressed version of the signal at a lower resolution that can be satisfactorily viewed in a single screen width. This reduced set of data is initially transmitted together with a set of 'flags' indicating where significant events occur. Subsequent transmissions need only involve transmission of flagged data segments of interest at the required resolution. Efficient processing and code protection with decomposition alone is novel. The fixed transmission length method ensures clutter-less display, irrespective of the data length. The flagging of annotated events in arterial oxygen saturation, electroencephalogram and electrocardiogram illustrates the generic property of the algorithm. Data reduction of 87% to 99% and improved displays are demonstrated.

[Plague in the port of Mahajanga: 6 inhabitants out of 1000 carry the anti-F1 antibody in 1999]

The authors report the results of a randomized epidemiological survey aiming to assess the sero-prevalence of plague in the general population > or = 2-year-old in Mahajanga. In 656 sera tested (by ELISA), the prevalence of anti-F1 antibodies was found to be 6.1%@1000 inhabitants, close to the expected prevalence in the area, where plague reappeared in 1991 after 62 years of absence. The study also demonstrated that the shrew, Suncus murinus, is an important reservoir in the plague transmission in Mahajanga.

Indium-Mediated Organometallic Reactions in Aqueous Media. Stereoselectivity in the Crotylation of Sulfonimines Bearing a Proximal Chelating Group

Reaction of sulfonimines having proximal chelating groups with crotyl bromide and indium in aqueous media gave alpha-crotylation products stereoselectively with syn-selectivity.

Enantioselective synthesis of epigallocatechin-3-gallate (EGCG), the active polyphenol component from green tea

[reaction: see text]. Enantioselective synthesis of epigallocatechin-3-gallate (EGCG, 3b), the active polyphenol component from green tea, has been achieved by using a stereospecific cyclization of the Sharpless asymmetric dihydroxylation product 7c as the key step.

Organometallic reactions in aqueous media. Indium- and zinc-mediated allylation of sulfonimines

Sulfonimines derived from aryl and nonenolizable aliphatic aldehydes can be effectively allylated to the corresponding homoallylic sulfonamides with allylic bromides promoted by indium or zinc. The solvent used can be water, THF, or a mixed aqueous THF solvent. The regioselectivity and stereoselectivity of the reaction were studied.

Cytokinetics of a novel 1,2,3-triazene-containing heterocycle, 8-nitro-3-methyl-benzo-1,2,3,5-tetrazepin-4(3H)-one (NIME), in the human epithelial ovarian cancer cell line OVCAR-3

The mechanism of action of the novel tetrazepinone 8-nitro-3-methyl-benzo-1,2,3,5-tetrazepin-4(3H)-one (NIME), structurally related to the antitumour drug temozolomide, was studied in the human ovarian tumour cell line OVCAR-3. NIME preferentially inhibited DNA synthesis over protein and RNA syntheses at 3 and 24 hr post-treatment. A Maxam-Gilbert sequencing assay showed that NIME induced barely detectable levels of guanine N7 alkylation in an isolated DNA strand, in contrast to temozolomide, a strong alkylating agent containing, like NIME, a cyclic 3-methyl-1,2,3-triazene moiety. Alkaline sucrose density-gradient sedimentation, at concentrations 2- to 10-fold lower than the ones used in the DNA sequencing assay, showed significant DNA damage in OVCAR-3 cells 24 hr after treatment with NIME. This was accompanied by a significant accumulation of cells in late S and G2M. Cell cycle arrest was transient and was reversed after 2-3 days following drug treatment. This was in agreement with bivariate bromodeoxyuridine/propidium iodide analysis, which showed that at 100 microM, a concentration at which the majority of the cells arrested in late S and G2M, a significant fraction of bromodeoxyuridine positive (S-phase) cells escaped the block. In an attempt to elucidate the mechanism underlying these effects, the degradation of NIME in cell culture medium was analyzed by GC-MS (gas chromatography coupled with mass spectrometry). The results showed that, in contrast to temozolomide, NIME did not convert to an open-chain alkyltriazene in cell culture medium, but to a major benzimidazole product, which exerted a minor effect on the cell cycle. This suggests that NIME, despite containing a 3-(alkyl)-1,2,3-triazene moiety, does not act by DNA alkylation but probably by generating a short-lived genotoxic species during its degradation to 6,5-benzofused derivatives.

Tetrazepinones are equally cytotoxic to Mer+ and Mer- human tumor cell lines

Human brain and colon tumor cell lines SF-188 (Mer+) and WiDR (Mer+), which express the DNA repair protein O6-methylguanine-DNA methyl transferase (MGMT), were 3- to 30-fold less sensitive to temozolomide, mitozolomide, and N, N'-bis(2-chloroethyl)-N-nitrosourea (BCNU) than the MGMT-deficient tumor cells SF-126 (Mer-) and BE (Mer-). This differential sensitivity was not observed when these cells were exposed to the novel tetrazepinones PYRZ, NIME, QUINCL, and PYRCL, which contain, like temozolomide and mitozolomide, a ureido-triazene moiety. Flow cytometric studies revealed that temozolomide induced G2-M arrest in the Mer- cells, but exerted a minor effect on the cycle of the Mer+ cells. Similarly, mitozolomide (25-100 microM) induced a stronger S-phase arrest in the SF-126 cells than in the SF-188 cells. In the same dose range (25-100) BCNU induced a significant cell cycle accumulation in G22-M in the SF-126 cells but little in the SF-188 cell line. In contrast, the cell cycle effects of the tetrazepinones were independent of the cell phenotypes. When O6-benzylguanine (O6-BG) was used to deplete MGMT activity in the SF brain tumor cell lines, significant potentiation of temozolomide (67-fold), mitozolomide (7-fold), and BCNU (3-fold) was observed in the SF-188 cell line. By contrast, O6-BG did not potentiate PYRZ, PYRCL, QUINCL, and NIME. Moreover, an MGMT inhibitory assay showed that all the tetrazepinones were capable of inactivating MGMT in the SF-188 cell line, the strongest inhibitor being PYRCL. The results suggest that, unlike temozolomide, mitozolomide, and BCNU, the cytotoxicity of the tetrazepinones does not correlate with the alkylation of the O6 position of guanine and that the mechanism of MGMT inactivation by tetrazepinones may differ from that of hitherto known inhibitors.

Synthesis and structure-activity relationships of 2-pyrazinylcarboxamidobenzoates and beta-ionylideneacetamidobenzoates with retinoidal activity

The structure-activity relationships of two series of novel retinoids (2-pyrazinylcarboxamidobenzoates and beta-ionylideneacetamidobenzoates) have been investigated by evaluating their ability to induce differentiation in both human promyelocytic leukemia (HL60) cells and mouse embryonal carcinoma (P19) cells. The most active compound (ED50 = 8.3 x 10(-9) M) of the 2-pyrazinylcarboxamidobenzoates is 4-[2-(5,6,7,8-tetrahydro-5,5,8, 8-tetramethylquinoxalyl)carboxamido]benzoic acid (9u), while the most active analogue of the beta-ionylideneacetamidobenzoates is 4-[3-methyl-5-(2',6',6'-trimethyl-1'-cyclohexen-1'-yl)-(2E, 4E)-pentadienamido]benzoic acid (10a, ED50 = 3.2 x 10(-8) M). Our studies identify an absolute requirement for the carboxylic acid moiety on the aromatic ring to be para relative to the amide linkage for activity. Benzoate substitutions in the ortho position relative to the terminal carboxylate (9d,k,r) are well-tolerated; however, a methoxy substituent meta relative to the terminal carboxylate gives rise to only weakly active analogues (9x). Conformational studies (NMR, X-ray crystallography) of the 2-pyrazinylcarboxamidobenzoates indicate that the preferred conformation exhibits a trans-amide bond and an internal hydrogen bond between the quinoxaline N1 and HN amide which locks the torsional angle between C2 and CO in the s-trans conformation. N-Methylation (9y) results in loss of activity. Studies indicate that there is now a cis-amide bond present which redirects the carboxylate toward the pharmacophoric gem-dimethyl groups. The distance between the gem-dimethyl group and the terminal carboxylate appears to be too short to activate the retinoid receptor. N-Methylation in the beta-ionylideneacetamidobenzoate series (10c) also results in the formation of a cis-amide bond and loss of activity.

Comparative studies between the effects of mitozolomide and two novel tetrazepinones PYRCL and QUINCL on NIH:OVCAR-3 cells

Cytotoxicity, reduction of macromolecule synthesis and cell cycle perturbations by two novel 3-(2-chloroethyl)-tetrazepinones, PYRCL and QUINCL were compared with those produced by the structurally related 3-(2-chloroethyl)-tetrazinone, mitozolomide, in the OVCAR-3 cell line.

METHODS

Macromolecule synthesis was determined by incorporation of 3H-thymidine, 3H-uridine and 3H-leucine into acid-precipitable fractions of OVCAR-3 cell extracts. Maxam-Gilbert sequencing was used to compare the DNA alkylating sites induced by the tetrazepinones, with those created by mitozolomide. Alkaline sucrose-density sedimentation was employed to detect genomic DNA damage. Also, the effects of the tetrazepinones on the cell cycle were determined by univariate flow cytometry.

RESULTS

At 3 h post-treatment, mitozolomide appeared as a selective inhibitor of DNA synthesis, while both tetrazepinones inhibited the synthesis of all three macromolecules. At 24 h post-treatment, the inhibition of DNA synthesis was observed to increase in cells treated with mitozolomide, while it decreased in those previously exposed to the tetrazepinones. Also at 24 h post-treatment, mitozolomide induced accumulation of cells in S(late)/G2M at low concentrations and in S-middle at high concentrations. In contrast, at the same recovery time, cells treated with the tetrazepinones accumulated specifically in G2M, the strength of the block being dose-dependent. At an equimolar concentration, the tetrazepinones induced weaker guanine N-7 alkylation than mitozolomide. By 24 h after treatment, cells exposed to the tetrazepinones showed significantly greater DNA fragmentation than those previously treated with mitozolomide.

CONCLUSION

In summary, based on (a) their effects on DNA, RNA, protein synthesis and on the cell cycle, (b) their alkylating power and (c) their interactions with DNA, the 3-(2-chloroethyl)tetrazepinones appeared to kill tumor cells by a novel mechanism which may significantly differ from that of their 3-(2-chloroethyl)-tetrazinone counterpart, mitozolomide.

Assisted reproduction technology in Queen Mary Hospital: ten years' experience

PURPOSE

To review the experience of an assisted reproduction program.

DATA SOURCES

Department of Obstetrics and Gynaecology, University of Hong Kong.

STUDY SELECTION

Assisted reproduction in a tertiary referral centre.

DATA EXTRACTION

Results of assisted reproduction from 1986-1996.

RESULTS

In the past ten years, 1561 treatment cycles of in vitro fertilization and embryo transfer (IVF), 257 of gamete intrafallopian transfer (GIFT) and 217 of pronuclear stage tubal transfer (PROST) were initiated. The clinical pregnancy rates per cycle started were 10.8% for IVF, 16.3% for GIFT and 15.7% for PROST. As a result of improvement in ovarian stimulation and embryo culture, the success rate of the program increased in recent years. The pregnancy rate of IVF per embryo transfer was 20.2% in 1995. Embryo cryopreservation program was started in 1992. Since then, 664 cycles of replacement of frozen-thawed embryos were completed with a pregnancy rate of 14.6% per cycle. One hundred and forty-three cycles of assisted fertilization using various techniques, namely partial zona dissection, subzonal sperm injection and intracytoplasmic sperm injection, were performed. The success rate was the highest for the latter technique with a pregnancy rate of 14% per transfer cycle. A prospective randomized control trial on the use of coculture in assisted reproduction had also been done. Results indicated that coculture of embryos with human oviductal cells improved the implantation rate of the embryos.

CONCLUSION

Various technique development have been made to improve the success rate of assisted reproduction as well as the quality of treatment of infertility.

Design and mechanism of action of a novel cytotoxic 1,2,3-triazene-containing heterocycle, 3,5-dimethyl-pyrido-1,2,3,5-tetrazepin-4-one (PYRZ), in the human epithelial ovarian cancer cell line NIH:OVCAR-3 in vitro

The mechanism of action of the novel heterocycle 3,5-dimethyl-pyrido-1,2,3,5-tetrazepin-4-one (PYRZ), structurally related to temozolomide, was studied in the human ovarian tumour cell line OVCAR-3. Our results showed that, despite its marked structural similarities to temozolomide, PYRZ presents properties that are atypical of 1,2,3-triazene-containing alkylating agents. In a Maxam-Gilbert DNA sequencing assay, PYRZ showed background levels of DNA alkylation, in contrast to temozolomide which strongly alkylated DNA preferentially at guanine residues. At high concentrations, PYRZ inhibited the synthesis of DNA, RNA and protein 3 h after treatment, in contrast to temozolomide which, in previous work, was found to preferentially inhibit DNA synthesis in OVCAR-3 cells. In cells exposed to PYRZ, alkaline sucrose density-gradient centrifugation showed a dose-dependent increase in DNA fragmentation only 12 and 24 h after treatment. PYRZ induced increasing accumulation of cells in late S and G2+M 6-24 h after treatment. This also contrasts with previous work that showed delayed cell cycle arrest induced by temozolomide in OVCAR-3 cells and in the murine leukaemia L1210 cells. Cell-killing kinetics by PYRZ showed a series of sigmoidal dose-response curves with 50-90% cell killing attained as early as 24 h after treatment in the 25-100 microM dose range. (IC50 clonogenic assay 18 microM). The results suggest that the mechanism of cell killing by PYRZ may be different from that of its parent drug temozolomide, and other alkyl-triazene-containing molecules of the same class.

Hospitalized patients with community-acquired pneumonia in Hong Kong: a randomized study comparing imipenem/cilastatin and ceftazidime

The aetiology and outcome of hospitalized patients with moderate to severe community-acquired pneumonia (CAP) were evaluated in 60 adult patients (38 male 22 female, mean age 68.4 years). They were randomized for treatment with either ceftazidime or imipenem/cilastatin intravenously for 7 days. Bacteriological diagnoses were made in 25 cases (41.6%): Streptococcus pneumoniae (5), Haemophilus influenzae (5), Pseudomonas spp. in particular Pseudomonas aeruginosa (8), Staphylococcus aureus (4), Chlamydia spp. (2), Mycobacterium tuberculosis (2) and Moraxella catarrhalis (3); mixed organisms were found in 4 patients. Forty-two patients (70%) responded satisfactorily to the regimens with improvement in sputum purulence cough and dyspnoea scores; there was no difference in response between the two groups. Sixteen patients (26.6%) underwent bronchoscopy on day 4 because of inadequate response to the antibiotics regimens, and 9 of them (15%) required a modification of the initial treatment with addition of erythromycin in 5 patients vancomycin in 1 cloxacillin in 1 and antituberculous drugs in 2. Three out of the 60 patients (5%) died of pulmonary sepsis: the aetiological agents were M. tuberculosis in one, Pseudomonas spp./methicillin-resistant S. aureus in another, but were not identified in the third. We conclude that treatment with either ceftazidime or imipenem/cilastatin was efficacious for moderate to severe CAP in Hong Kong.

Urinary tract infection caused by Mycobacterium terrae complex

We describe a case of recurrent urinary tract infection caused by Mycobacterium terrae complex in a patient with obstructive nephropathy. The mycobacterium was resistant to most antituberculosis drugs and despite its apparent clearance in the urine, the patient finally died of urinary sepsis caused by multiple bacterial pathogens.

Comparison of oral ciprofloxacin and amoxycillin in treating infective exacerbations of bronchiectasis in Hong Kong

A randomised double-blind controlled clinical trial was conducted to compare oral ciprofloxacin (500 mg b.d.) and amoxycillin (1 g t.d.s.) in the treatment of infective exacerbations of bronchiectasis. The commonest organism isolated from sputum was Pseudomonas aeruginosa, which accounted for 34% of all positive sputum cultures. Other Pseudomonas species and Haemophilus influenzae, accounted for 19%, respectively. Ciprofloxacin produced better clinical response, a higher sputum to serum antibiotic level (mean of 0.65 in the ciprofloxacin group vs. 0.18 in amoxycillin group, p = 0.0001), broader spectrum of antibacterial activity and less side-effect. It was also better tolerated by patients. The findings suggest that ciprofloxacin is an effective treatment of infective exacerbations of bronchiectasis.

Paecilomyces varioti peritonitis in patients on continuous ambulatory peritoneal dialysis

Paecilomyces varioti infection is a rare cause of peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD). We report two patients who developed P varioti peritonitis complicating CAPD. The clinical features and microbiological data of seven other previously reported cases are reviewed. Approximately half of the patients had received multiple antibiotics before the onset of the peritonitis because of either bacterial peritonitis or exit site infection. There was no particular pattern of peritoneal dialysate cell count, which was characteristic in this fungal peritonitis. Although all patients survived, morbidity was high. All patients required antifungal chemotherapy and removal of peritoneal catheter for eradication of the organism. Amphotericin B was effective in most cases. Patients of all previously reported cases did not go back to peritoneal dialysis after removal of peritoneal catheters. A combination of oral flucytosine and itraconazole was successful in treating our two patients. Although we managed to resume CAPD in our two patients with good functional outcome, abscesses and adhesions were major problems rendering most patients from other series failing to return to CAPD after recovery.

Effect of fluvastatin on lipoprotein profiles in treating renal transplant recipients with dyslipoproteinemia

A single, blinded placebo-drug trial was conducted to study the efficacy and safety of fluvastatin, a new 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, in treating dyslipoproteinemia in 16 renal transplant recipients who had been on an immunosuppressive regimen that included cyclosporine (CsA). They were studied for 32 consecutive weeks, with 4 weeks of baseline treatment, 4 weeks of placebo, 12 weeks of treatment with fluvastatin 20 mg daily, and 12 weeks of fluvastatin 40 mg daily. Blood samples were obtained every 4 weeks for measurement of the lipoprotein profiles, which included total cholesterol (TC), triglyceride, low density lipoprotein (LDL)-, high density lipoprotein (HDL)-, HDL2-, HDL3- and very low density lipoprotein-cholesterol (C), apolipoprotein (Apo) A-1, Apo B, and lipoprotein(a). Fifteen patients completed the trial. After 12 weeks of treatment, fluvastatin 20 mg significantly reduced TC by 13.4% (from 6.7 +/- 0.5 [mean +/- SEM] to 5.8 +/- 0.2 mmol/L), LDL-C by 22% (from 4.1 +/- 0.3 to 3.2 +/- 0.2 mmol/L), and Apo B by 13.2% (from 159.6 +/- 8.8 to 138.6 +/- 9.2 mg/dl) (P < 0.005). The subsequent 12-week treatment of fluvastatin 40 mg significantly reduced TC by 16.4% to 5.6 +/- 0.3 mmol/L, LDL-C by 29.3% to 2.9 +/- 0.2 mmol/L, and Apo B by 18.2% to 130.6 +/- 5.5 mg/dl (P < 0.00005). There was no significant change in levels of other lipoproteins, including lipoprotein (a). There were no significant changes in the whole blood trough CsA concentrations, renal and liver function tests, and serum creatine phosphokinase level during treatment when compared with baseline and placebo. No patient complained of myalgia or failed to complete the study due to side effects of the drug. Fluvastatin appears to be safe and effective in treating dyslipoproteinemia in renal transplant recipients who are maintained on CsA.

Molecular genetics of major histocompatibility complex class II genes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver with a possible genetic predisposition. We have studied the HLA-DQ and -DR regions of 57 unrelated HCC patients of southern Chinese origin using molecular DNA techniques and compared them with 104 normal controls. Seventy-six hepatitis B carriers (HBsAg) were also studied. Restriction fragment length polymorphism (RFLP) was used to genotype the MHC class II DR beta, DQ alpha and DQ beta loci of the subjects. Polymerase chain reaction (PCR) using sequence primer for DQ beta genes was also performed. No significant difference was found in the HLA-DQ and -DR loci between HCC patients and normal controls, HCC patients and HBsAg carriers, or HBsAg carriers and normal controls respectively. Forty-one HCC patients were HBsAg positive, and no difference was found in the HLA-DQ and -DR genotype between this group of patients compared with the group of normal controls or HBsAg carriers. Thirty-six HCC patients had elevated alpha-fetoprotein levels, and 15 HCC patients had normal levels. No difference in the HLA-DQ and -DR loci was detected between these two groups and the controls. The results suggest that HLA-DQ and -DR genotypes are not associated with hepatocellular carcinoma in southern Chinese.

Coping process theory: a tool to reduce stress and cardiovascular disease

1. Associations exist between stress and cardiovascular disease. This article presents the coping process theory as a possible strategy to reduce the incidence of cardiovascular disease. 2. The occurrence of coronary heart disease may be reduced by using the coping process to manage stress in the workplace. If the disease is present, coping with the stress of having the disorder diminishes its recurrence. 3. Social support is a valuable coping resource; its association with cardiovascular disease is demonstrated.

Adenosine deaminase binding protein, a new diagnostic marker for kidney disease

This enzyme immunoassay detects adenosine deaminase binding protein (ABP), a glycoprotein that is shed from the brush border of the proximal tubule in kidney damage. Two monoclonal antibodies, URO-4 and URO-4a, each react with different epitopes on ABP and are used as the "sandwich" pair of antibodies. A linear standard curve can be generated by using partly purified ABP isolated from the urine of patients with kidney disease. Release of ABP into the urine appears to reflect the severity of the insult to the nephron. Therefore, measurement of ABP in urine may help distinguish between tubular disease and glomerular disease and indicate renal allograft rejection in renal-transplant patients.

Adenosine deaminase binding protein, a new diagnostic marker for kidney disease

This enzyme immunoassay detects adenosine deaminase binding protein (ABP), a glycoprotein that is shed from the brush border of the proximal tubule in kidney damage. Two monoclonal antibodies, URO-4 and URO-4a, each react with different epitopes on ABP and are used as the "sandwich" pair of antibodies. A linear standard curve can be generated by using partly purified ABP isolated from the urine of patients with kidney disease. Release of ABP into the urine appears to reflect the severity of the insult to the nephron. Therefore, measurement of ABP in urine may help distinguish between tubular disease and glomerular disease and indicate renal allograft rejection in renal-transplant patients.

The isolation and further characterization of the bilirubin tetrapyrroles in bile-containing human duodenal juice and dog gall-bladder bile

Bilirubin and its conjugates were extracted from either dog gall-bladder bile or bile-containing human duodenal juice into chloroform containing 10mm-tetraheptylammonium chloride. The intact bilirubin tetrapyrroles were then separated by t.l.c. Structural elucidation was made after coupling of the individual pigments with diazonium salts. Four azopigments were detected: azopigment alpha(o) or dipyrrolic azobilirubin; azopigment delta or dipyrrolic azobilirubin monoglucuronide; azopigment alpha(3) or dipyrrolic azobilirubin monoglucoside; and, from dog gall-bladder bile, azopigment alpha(2). The last conjugate required further verification of its structure. After methanolysis, it was shown by combined g.l.c.-mass spectrometry to contain xylose in a 1:1 molar ratio with the azopigments of bilirubin. Human bile contained 86% bilirubin diglucuronide, 7% bilirubin monoglucuronide monoglucoside diester, 4% bilirubin monoglucuronide and 3% bilirubin. Dog gall-bladder bile had a considerably different composition; it contained 47% bilirubin diglucuronide, 40% bilirubin monoglucuronide monoglucoside diester, 8% bilirubin monoglucuronide, 4% bilirubin diglucoside, 1-2% bilirubin and traces of conjugates containing xylose. The total bilirubin content and proportions of the conjugates did not change in bile that was frozen and stored at -20 degrees C under N(2), whereas in the chloroform/tetraheptylammonium chloride extract, similarly stored, total pigment was slowly lost and the diglucuronide conjugate converted into the monoglucuronide.

Biologically active substances in oak gall extracts. Part 1: Isolation and chemical identification of a substance exerting antihistamine-like activity (KC-18)

The previously reported antihistamine-like activity of partially purified oak gall extracts has been confirmed. Isolation of the active principle was achieved through the use of organic solvent extractions and column chromatographic (Sephadex LH-20 and silica gel) procedures. Preliminary investigation on the structure of this chemically pure substance using mass spectrometry, thin layer chromatography, base hydrolysis and electrophoresis indicated that it is most probably an ester of piperonylic acid. KC-18, given intraperitoneally in doses of 4 mg/kg to guinea pigs 5 hours prior to an exposure to a 0.15 per cent histamine aerosol, significantly reduced the bronchoconstrictor effect of histamine.

The isolation of an azobilirubin beta-D-monoglucoside from dog gall-bladder bile

An ethyl anthranilate azopigment of bilirubin conjugated to beta-d-monoglucoside was isolated from dog gall-bladder bile. Glucose was cleaved from the azopigment by treatment with beta-glucosidase and beta-glucuronidase. Mild alkaline hydrolysis of the compound by sodium methoxide yielded two kinds of compounds, water-soluble and organic-soluble. The former were shown, by enzymic analysis, t.l.c., nuclear magnetic resonance, and combined g.l.c. and mass spectrometry, to contain glucose. No evidence was obtained from these data that a disaccharide was present in this fraction. The organic-soluble compounds formed during this methanolysis were shown, by t.l.c. and mass spectrometry, to be the isomeric dipyrrole azopigments of bilirubin. These findings contribute further evidence to the controversy surrounding the nature of conjugated bilirubin.

Hypertensive action of 18-hydroxydeoxycorticosterone

18-Hydroxydeoxycorticosterone is an adrenal steroid hormone causing salt and water retention and is secreted in greatly increased amounts in response to the pituitary hormone adrenocorticotropic hormone. Its production is abnormally high in some forms of hypertension in man and rat. Direct proof that 18-hydroxydeoxycorticosterone is capable of causing hypertension is present. Daily subcutaneous injections of 200 micrograms, a low physiological dose, significantly increase the blood pressure of unilaterally nephrectomized saline-treated rats after 2 weeks. This strengthens the hypothesis that 18-hydroxydeoxycorticosterone contributes to the etiology of hypertension, possibly by a mechanism involving stressinduced release of adrenocorticotropic hormone.

Synthesis of glycerol-1,3-diphosphate

Glycerol-1,3-diphosphate was synthesized in an overall yield of 40% by the following sequence of reactions. 1,3-Dibromo-2-propanol was esterified with palmitoyl chloride in quinoline to give 1,3-dibromo-2-hexadecanoyloxypropane (I). Reaction of I with 2 moles of silver dibenzyl phosphate in boiling benzene gave tetrabenzyl 2-hexadecanoyl-1,3-glycerodiphosphate (II). The benzyl groups were removed from II by catalytic hydrogenolysis with palladium on charcoal, and the palmitoyl group was removed by mild alkaline hydrolysis. The resulting glycerol-1,3-diphosphate (IV) was isolated as the dibarium salt.