Extracts of North Sea macroalgae reveal specific activity patterns against attachment and proliferation of benthic diatoms: a laboratory study

A variety of macroalgae (Ceramium rubrum, Corallina officinalis, Palmaria palmata, Mastocarpus stellatus, Fucus vesiculosus, Cladophora rupestris, Ulva sp.) were investigated by scanning electron microscopy to visualize epiphytic colonizers. The macroalgae differed in terms of their epiphytic coverage of bacteria, fungi and diatoms. Macroalgae, largely devoid of epiphytic diatoms, were hypothesized to employ effective antifouling means to reduce epiphytic coverage, whilst heavily fouled macroalgae were proposed to lack antifouling strategies. To test these hypotheses from an allelochemical perspective with regard to fouling diatoms, dichloromethane-methanol (1:1) crude extracts of macroalgae were concentrated in dimethylsulfoxide and investigated in diatom attachment and proliferation assays using four benthic diatoms (Nitzschia sp., Navicula phyllepta, Navicula arenaria and Amphora sp.). Algal extracts exhibited a distinct pattern of activity against the test diatoms, suggesting a targeted and selective effect of macroalgal metabolites on individual fouling diatoms. The main outcome of this study was that visual inspection and quantitative categorization of epiphytic colonizers on macroalgal thalli could not be used to predict reliably whether macroalgae employed a chemical defense mechanism.

Potential of COX-2 inhibitors in lowering chemotherapy-induced neutropenia: Results from a randomized trial

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Background: This study was to evaluate the effect of celecoxib on the regimen 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) combination, followed by docetaxel in neoadjuvant setting. Patients and Methods: Twenty-three female patients with operable breast cancer were randomized into two groups: group A (n=12), four cycles of FEC (500 mg/m2, 100 mg/m2, 500 mg/m2) followed by four cycles of docetaxel (100 mg/m2) with concurrent celecoxib (400 mg twice daily); group B (n=11), same chemotherapy regimen but without concurrent celecoxib. These combined chemotherapies were administered 3-weekly. Results: 22 (96%) patients completed all cycles except that one (4%) omitted the fourth cycle of FEC owing to repeated incidences of febrile neutropenia. Received dose intensity (RDI) of group A and B for FEC (90% vs. 80%, p=0.035) and docetaxel (93% vs. 96%, p=0.414) showed significant difference in first four cycles of FEC between groups. Limiting hematological toxicity, severe neutropenia including febrile neutropenia, was significantly different between group A and B (33.3% vs 90.9%, p=0.005) during the first four cycles of FEC. Other toxicities commonly observed in chemotherapy receiving patients were manageable. Conclusion: Neoadjuvant use of FEC followed by docetaxel with concurrent celecoxib is safe for treatment of operable invasive breast cancer. COX-2 inhibitor likely lowers the incidence of chemotherapy-induced neutropenia. We believe that further investigation might provide more evidence on the use of COX-2 inhibitors in breast cancer.

No significant financial relationships to disclose.

Community attitudes toward living arrangements between the elderly and their adult children in Hong Kong

For hundreds of years, Chinese societies have been living in extended family settings. However, the import of Western cultures and values are challenging the traditional Chinese practices in Hong Kong. This study assesses the community attitudes to living arrangements between elderly and their adult children in Hong Kong and to identify the factors which influence these attitudes. A random sample of 888 adult Hong Kong residents were telephone-interviewed. They were asked about their attitudes to living arrangements when they turned 60, if disabled and non-disabled. The relationship between these attitudes and the social and demographic characteristics of the respondents was also analyzed. Nearly 59% of the respondents preferred to live with their children if non-disabled. However, 43.5% of the respondents would be unlikely to want to live with their children if disabled. If non-disabled at 60, females, professionals or those who had lived overseas before preferred not to live with their children. Females also preferred not to live with their children if disabled at 60. Other factors, such as age, social class, education level and experience in living with elderly or looking after elderly had no effect on the respondents' preference. This study provides important information on the community attitudes to living arrangements between the elderly and their adult children in Hong Kong. These attitudes will shed light on the provision of housing and institutional care to elderly, as well as the family relationship and care pattern of the elderly in the future decades in Hong Kong and other communities which are undergoing rapid growth and 'Westernization'.

Clinical profile and genetic basis of Brugada syndrome in the Chinese population

OBJECTIVE

To study the clinical profile and genetic basis of Brugada syndrome in Chinese patients.

DESIGN

Prospective observational study.

SETTING

Seven regional public hospitals, Hong Kong.

MAIN OUTCOME MEASURES

The clinical and follow-up data of 50 patients (47 men, 3 women; mean age, 53 years) were collected, and genetic data of 36 probands and eight family members of three genotyped probands were analysed.

RESULTS

Eight patients survived sudden cardiac death (group A), 12 had syncope of unknown origin but no sudden death (group B), and 30 were asymptomatic before recognition of Brugada syndrome (group C). Programmed electrical stimulation induced sustained ventricular arrhythmias in 88% (7/8), 82% (9/11), and 27% (3/11) of patients in group A, group B, and group C, respectively. New arrhythmic events occurred in 50% (4/8) of patients in group A and 17% (2/12) of patients in group B after a mean follow-up period of 30 (standard deviation, 13) months and 25 (7) months, respectively. All group C patients remained asymptomatic during a mean follow-up period of 25 (standard deviation, 11) months. Five of 36 probands and three of eight family members who underwent genetic testing were found to have a mutation in their SCN5A gene.

CONCLUSIONS

Chinese patients with Brugada syndrome who are symptomatic have a high likelihood of arrhythmia recurrence, whereas asymptomatic patients enjoy a good short-term prognosis. The prevalence of SCN5A mutation among probands is 14%. Thus, Chinese patients with Brugada syndrome share with their western counterparts similar clinical and genetic heterogeneity.

Particle effects on ultraviolet disinfection of coliform bacteria in recycled water

Pilot- and bench-scale coliform inactivation tests with UV irradiation were used to show how suspended solids remaining in filtered secondary effluent affect the efficiency of the UV disinfection process. Observed kinetic inactivation rates decreased with increasing suspended particle sizes of 7 microm or larger present in tertiary effluent. First-order inactivation rates estimated from collimated beam dose-response curves for discrete ranges of UV doses were substantially different, which should caution researchers not to compare inactivation data obtained with largely dissimilar UV doses or suspended particle distributions. A dose of approximately 800 J/m2 was identified as the minimum dose that will consistently meet the California wastewater reclamation coliform criterion when applied to in-line filtration effluent.

Distinct tumour specificity and IL-7 requirements of CD56(-)and CD56(+) subsets of human gamma delta T cells

gamma delta T cells are believed to recognize tissue injury caused by infections, tumours, as well as chemical and physical agents. The present study was carried out to study the feasibility of the ex vivo expansion of gamma delta T cells from healthy individuals, and to determine their functional capacity against tumours. We selectively expanded the peripheral gamma delta T cells of five donors against a myeloma cell line, XG-7. Under optimal conditions, the resulting bulk cultures comprised about 82% of the gamma delta T cells, more than 90% of which showed the T-cell receptor (TCR)-V gamma 9 delta 2 rearrangement. These gamma delta T-cell cultures exhibited TCR-gamma delta dependent cytotoxicity against different tumour cell lines including Molt-4, BJAB, Epstein-Barr virus (EBV) transformed lymphoid cell lines (LCL), and the nasopharyngeal carcinoma (NPC) cell lines, CNE2 and 915, in addition to the stimulator XG-7. By competitive cytotoxicity assays, the gamma delta T cells demonstrated recognition of at least three distinct target specificities expressed by Molt-4, CNE2 and LCL, respectively, which were related to that expressed by the stimulator XG-7 cells. The recognition of the specificity expressed by XG-7 and Molt-4 was further shown to require the participation of heat shock protein (HSP). The specificity expressed by CNE2 and 915 was preferentially recognized by the CD56 subset of gamma delta T cells, which could be sustained in the presence of interleukin (IL)-7. These results suggested that gamma delta T-cell immunity against tumour cell lines may be acquired in response to other types of tissue injury and, hence, implicates a role for their use in the prevention and treatment of tumours.

Conditional gene expression in the epidermis of transgenic mice using the tetracycline-regulated transactivators tTA and rTA linked to the keratin 5 promoter

To produce conditional expression of genes in the mouse epidermis we have generated transgenic mouse lines in which the tetracycline-regulated transcriptional transactivators, tTA and rTA, are linked to the bovine keratin 5 promoter. The transactivator lines were crossed with the tetOlacZ indicator line to test for transactivation in vivo. In the absence of doxycycline, the K5/tTA line induced beta-galactosidase enzyme activity in the epidermis at a level 500-fold higher than controls, and oral and topical doxycycline caused a dose- and time-dependent suppression of beta-galactosidase mRNA levels and enzyme activity. In the K5/rTA lines, doxycycline induced beta-galactosidase activity between 3- and 50-fold higher depending on the founder line, and this occurred within 24-48 h after dosing. Histochemical analysis of all lines localized beta-galactosidase expression to the basal layer of the epidermis and the outer root sheath of the hair follicle, as well as other keratin 5 positive tissues. In several K5/rTA lines, skin-specific transactivation was restricted to the hair follicle. Treatment of these double transgenic mice with 12-O-tetradecanoyl-phorbol-13-acetate caused rapid migration of beta-galactosidase marked cells from the hair follicle through the interfollicular epidermis, demonstrating the usefulness of this specific double transgenic for fate mapping cells in the epidermis. These results show that the tetracycline regulatory system produces effective conditional gene expression in the mouse epidermis, and suggest that it should be amenable to suppression and activation of foreign genes during development and specific pathologic conditions relevant to the epidermis.

Radiofrequency ablation of a right atrial appendage-ventricular accessory pathway by transcutaneous epicardial instrumentation

Epicardial location of accessory AV pathways may be responsible for the failure of conventional endocardial radiofrequency catheter ablation. Transcutaneous epicardial instrumentation provides access to the normal pericardium with no need for invasive thoracotomy or thoracoscopy. We report the case of successful epicardial mapping and ablation of a right atrial appendage-ventricular connection using a percutaneous epicardial approach, after repeated failure of endocardial ablation attempts.

MECP2 mutation in male patients with non-specific X-linked mental retardation

In contrast to the preponderance of affected males in families with X-linked mental retardation, Rett syndrome (RTT) is a neurological disorder occurring almost exclusively in females. The near complete absence of affected males in RTT families has been explained by the lethal effect of an X-linked gene mutation in hemizygous affected males. We report here on a novel mutation (A140V) in the MECP2 gene detected in one female with mild mental retardation. In a family study, the A140V mutation was found to segregate in the affected daughter and in four adult sons with severe mental retardation. These results indicate that MECP2 mutations are not necessarily lethal in males and that they can be causative of non-specific X-linked mental retardation.

Complete reversal of fatal pulmonary hypertension in rats by a serine elastase inhibitor

Progression of pulmonary hypertension is associated with increased serine elastase activity and the proteinase-dependent deposition of the extracellular matrix smooth muscle cell survival factor tenascin-C (refs. 1,2). Tenascin-C amplifies the response of smooth muscle cells to growth factors, which are also liberated through matrix proteolysis. Recent organ culture studies using hypertrophied rat pulmonary arteries have shown that elastase inhibitors suppress tenascin-C and induce smooth muscle cell apoptosis. This initiates complete regression of the hypertrophied vessel wall by a coordinated loss of cellularity and extracellular matrix. We now report that elastase inhibitors can reverse advanced pulmonary vascular disease produced in rats by injecting monocrotaline, an endothelial toxin. We began oral administration of the peptidyl trifluoromethylketone serine elastase inhibitors M249314 or ZD0892 21 days after injection of monocrotaline. A 1-week treatment resulted in 92% survival, compared with 39% survival in untreated or vehicle-treated rats. Pulmonary artery pressure and muscularization were reduced by myocyte apoptosis and loss of extracellular matrix, specifically elastin and tenascin-C. After 2 weeks, pulmonary artery pressure and structure normalized, and survival was 86%, compared with 0% in untreated or vehicle-treated rats. Although concomitant treatment with various agents can reduce pulmonary hypertension, we have documented complete regression after establishment of malignant monocrotaline-induced disease.

Glomerulonephritis in a neonate with atypical congenital lupus and toxoplasmosis

The development of glomerulonephritis as a complication of neonatal lupus or congenital toxoplasmosis is extremely rare. We report a case of membranous glomerulonephritis occurring in a neonate with toxoplasmosis and atypical congenital lupus, including high-titer antinuclear antibodies and hypocomplementemia. This case illustrates that glomerulonephritis in the neonate may be induced by passively transferred maternal antibodies.

Mutations in the glucose-6-phosphate transporter (G6PT) gene in patients with glycogen storage diseases type 1b and 1c

Glycogen storage diseases type 1 (GSD 1) are a group of autosomal recessive disorders characterized by impairment of terminal steps of glycogenolysis and gluconeogenesis. Mutations of the glucose-6-phosphatase gene are responsible for the most frequent form of GSD 1, the subtype 1a, while mutations of the glucose-6-phosphate transporter gene (G6PT) have recently been shown to cause the non 1a forms of GSD, namely the 1b and 1c subtypes. Here, we report on the analysis by single-stranded conformation polymorphism (SSCP) and/or DNA sequencing of the exons of the G6PT in 14 patients diagnosed either as affected by the GSD 1b or 1c subtypes. Mutations in the G6PT gene were found in all patients. Four of the detected mutations were novel mutations, while the others were previously described. Our results confirm that the GSD 1b and 1c forms are due to mutations in the same gene, i.e. the G6PT gene. We also show that the same kind of mutation can be associated or not with evident clinical complications such as neutrophil impairment. Since no correlation between the type and position of the mutation and the severity of the disease was found, other unknown factors may cause the expression of symptoms, such as neutropenia, which dramatically influence the severity of the disease.

Factors affecting the central corneal thickness of Hong Kong-Chinese

PURPOSE

The aims of this study were to investigate the effect of age, intraocular pressure, refractive error (spherical equivalent) and corneal curvatures on the central corneal thickness of Hong Kong-Chinese. We also compared the central corneal thickness of Hong Kong-Chinese with those previously reported for other national/ethnic groups.

METHODS

The central corneal thicknesses of 151 subjects of age 10-60 yrs were measured using an ultrasound pachometer. Intraocular pressure, refractive error and the corneal curvatures of these subjects were also recorded.

RESULTS

The mean +/- SD central corneal thickness of the right eye and left eye were 575 +/- 32 microm and 574 +/- 31 microm respectively. No significant difference in central corneal thickness was found between the right and left eyes or between male and female subjects. Central corneal thickness decreased with increasing age but the effect appeared to be due to differences in female subjects only. The maximum decrease in central corneal thickness occurred in subjects in the age group of 10-25 yrs, and in this age group, central corneal thickness and age was significantly correlated in both male and female subjects. Intraocular pressure and central corneal thickness was significantly correlated. There was no correlation between central corneal thickness and refractive error or between central corneal thickness and corneal curvatures.

CONCLUSIONS

Central corneal thickness decreased with increasing age but this appeared to be due to female subjects only. Central corneal thickness was significantly correlated with intraocular pressure, but not with refractive error or corneal curvatures. Our subjects also had significantly thicker corneas than those reported for Caucasian subjects.

Nitric oxide regulates Th1 cell development through the inhibition of IL-12 synthesis by macrophages

We have previously reported that mice lacking inducible nitric oxide synthase (NOS2) developed enhanced Th1 cell responses. We now investigated the mechanism by which NO modulates Th1 cells differentiation. Peritoneal macrophages from NOS2-deficient mice infected with Leishmania major in vivo or stimulated with IFN-gamma or lipopolysaccharide (LPS) in vitro produced significantly higher levels of IL-12 than those from heterozygous or wild-type mice. A macrophage cell line, J774, produced significant amounts of IL-12 following activation with LPS, or LPS plus IFN-gamma. This could be markedly enhanced by the NOS inhibitor L-NG monomethyl arginine (L-NMMA), but profoundly inhibited by the NO-generating compound S-nitroso-N-acetyl-penicillamine (SNAP). The effect of NO in this system is selective, since SNAP enhanced and L-NMMA decreased TNF-alpha synthesis by LPS-activated J774 cells. The differential effect of NO on IL-12 and TNF-alpha is at the transcriptional level and is activation dependent. Since IL-12 is a major inducer of Th1 cells which produce IFN-gamma that can activate macrophages to produce IL-12, our data demonstrate that NO can be an inhibitor of this feedback loop, preventing the excessive amplification of Th1 cells which are implicated in a range of immunopathologies.

Bone marrow necrosis in bone marrow transplantation: the role of MR imaging

We describe an ALL patient who developed extensive bone marrow necrosis at the time of relapse 2 months after allogeneic bone marrow transplantation from an HLA-identical sibling. The excruciating and diffuse bone pain, fever and precipitous drop in peripheral blood counts were characteristic. This case illustrates the importance of repeat bone marrow biopsies for the diagnosis of disease relapse and the potential application of MR imaging in the assessment of patients with bone marrow necrosis.