Factors associated with transmission of severe acute respiratory syndrome among health-care workers in Singapore

Between 1 and 22 March 2003, a nosocomial outbreak of Severe Acute Respiratory Syndrome (SARS) occurred at the Communicable Disease Centre in Tan Tock Seng Hospital, Singapore, the national treatment and isolation facility for patients with SARS. A case-control study with 36 cases and 50 controls was conducted of factors associated with the transmission of SARS within the hospital. In univariate analysis, contact with respiratory secretions elevated the odds ratio to 6.9 (95 % CI 1.4-34.6, P= 0.02). Protection was conferred by hand washing (OR 0.06, 95% CI 0.007-0.5, P=0.03) and wearing of N95 masks (OR 0.1, 95% CI 0.03-0.4, P=0.001). Use of gloves and gowns had no effect. Multivariate analysis confirmed the strong role of contact with respiratory secretions (adjusted OR 21.8, 95 % CI 1.7 274.8, P=0.017). Both hand washing (adjusted OR 0.07, 95 % CI 0.008-0.66, P=0.02) and wearing of N95 masks (adjusted OR 0.1, 95% CI 0.02-0.86, P=0.04) remained strongly protective but gowns and gloves had no effect.

Dynamic aspects of acute tolerance to allopregnanolone evaluated using anaesthesia threshold in male rats

BACKGROUND

It is unclear if allopregnanolone (AlloP) anaesthesia can induce tolerance. Acute tolerance is defined as altered sensitivity to a drug during a single continuous exposure.

METHODS

Induction of acute tolerance to AlloP was studied in male rats using a threshold technique of deep anaesthesia. AlloP was infused at a dose rate of 4.0 mg kg(-1) min(-1). The infusion was stopped when a burst suppression of 1 s or more (the "silent second", SS) occurred in the EEG. To maintain anaesthesia, the infusion was restarted when no SS had been seen in the EEG for 1 min. This interrupted targeted infusion towards an EEG end-point (SS) was continued until 30, 60 or 90 min of anaesthesia had been reached. At these times the rats were killed and AlloP concentrations in serum, muscle, fat and different brain regions were determined by radioimmunoassay.

RESULTS

Maintenance dose rate (MDR) was calculated using 20-min intervals. During anaesthesia the MDR increased (P<0.001) from 0.67 (sem 0.03) mg kg(-1) min(-1) (in the interval 10-30 min) to 0.98 (0.04) mg kg(-1) min(-1) (in the interval 65-85 min). After 60 min a slight increase in MDR was observed. After 90 min of anaesthesia the AlloP concentrations in the hippocampus and brainstem had increased by more than 50% compared with control values of 25.2 (1.13) and 52.7 (5.81) nmol g(-1) respectively, and after 60 min to around 40%. At 30 min no increase was seen in any brain region analysed.

CONCLUSIONS

Measurements in vivo and in vitro record acute tolerance to AlloP occurring with a delay.

Co-activation of the phosphatidylinositol-3-kinase/Akt signaling pathway by N-methyl-D-aspartate and TrkB receptors in cerebellar granule cell neurons

Neuroprotective concentrations of N-methyl-D-aspartate (NMDA) promote survival of cerebellar granule cell neurons against glutamate excitotoxicity through a TrkB receptor-mediated brain-derived neurotrophic factor (BDNF) autocrine loop. However, the intracellular signaling pathway(s) are not clear. Our results show that PI-3 kinase/Akt is activated by either NMDA or BDNF displaying differential kinetics. BDNF and NMDA increased Akt phosphorylation within 5 minutes but maximal activation by NMDA was observed at 3 hours. Akt phosphorylation was completely blocked by the PI-3 kinase inhibitor LY294002. NMDA-mediated activation of Akt was completely blocked by MK-801 and partially blocked by the TrkB receptor inhibitor, K252a, indicating the requirement of TrkB receptors for maximal activation by NMDA. In contrast, BDNF-induced Akt phosphorylation was abolished by K252a, but not by the addition of MK-801. Therefore, the PI-3 kinase/Akt pathway is co-activated by NMDA and TrkB receptors. The kinetics of BDNF and NMDA-mediated activation of PI-3 kinase/Akt suggests that they have different roles in intraneuronal time-related events.

CMT with pyramidal features. Charcot-Marie-Tooth

To determine whether Charcot-Marie-Tooth (CMT) with pyramidal features is genetically distinct from other dominantly inherited axonal neuropathies, the authors examined all chromosomal loci and genes for axonal CMT. Two families were identified with an axonal CMT phenotype with distal wasting, weakness, pes cavus, sensory loss, and mild pyramidal signs (including extensor plantar responses, mild increase in tone, and preserved or increased reflexes but no spastic gait). Linkage studies excluded CMT2A, 2B, 2D, 2E, and 2F; ALS4; and HMN2. There were no mutations in the PMP22, MPZ/Po, or EGR2 genes.

[Studies on extensive application of bromoacetamide in various types of schistosomiasis endemic area]

AIM

To provide scientific basis for the popularization and application of molluscide bromoacetamide.

METHODS

Large scale application of bromoacetamide in twenty eight counties of four provinces was investigated and its molluscicidal effect in marshland and influence on marshland grass (Cyperus) and fishes were observed.

RESULTS

High molluscicidal effect of bromoacetamide was found against both snails and snail eggs in various environments. According to the results observed in different fields, the applicable dosage of bromoacetamide is 1.5-2 g/m2 for spraying method, 1.5-2 g/m3 for immersing method and 1.5-2 g/m for immersing in combination with shovelling the turf along the bank. When it was applied in fish-raising ponds or rivers at an applicable dosage, no toxic effect on fishes was found. The spraying dosage of bromoacetamide did not affect the rice seedling but it did some damage to the leaf-tips of marshland grass, however, the grass did turn green and grow.

CONCLUSION

Bromoacetamide has proved to be a safe and effective mulluscicde against Oncomelania under various field conditions.

The pattern of estradiol and progesterone differs in serum and tissue of benign and malignant ovarian tumors

Epidemiological studies have indicated a relationship between gonadal steroid hormones and ovarian cancer. A production of both estradiol and progesterone by ovarian cancers has been demonstrated. The local steroid concentrations and the putative relation to histopathological and clinical condition were investigated herein. Ovarian tissue, ovarian tumor cyst fluid, ovarian vein samples and peripheral serum concentrations of estradiol and progesterone in pre- and post-menopausal women, subdivided into groups with normal ovaries, benign, borderline and malignant ovarian tumors, were quantitatively assessed. Both ovarian tissue concentrations of estradiol and progesterone were more than 100-fold higher than in serum. Based on differences in concentrations between different ovarian tumor groups, the data is not coherent with the previously suggested increased production of estradiol and progesterone in ovarian cancer tissue, since post-menopausal women with ovarian cancer presented lower median tissue hormone levels, most pronounced between malignant and benign tumors; median (25 and 75 percentile) estradiol; 9.40 (6.67-15.50) vs 16.44 (12.49-23.20), p=0.02 and progesterone; 308 (240-575) vs 957 (553-1143) pmol/g wet weight, p<0.01, n=81. Lower concentrations of estradiol, but not progesterone, were found in ovarian cancer tissue, ovarian cyst fluid and peripheral serum in patients with FIGO stages 3 and 4 than in stages 1 and 2. The novel finding of a large ovarian tissue to serum difference of both estradiol and progesterone indicates an important role of ovarian tissue concentrations in tumor biology and raises the question of adequate doses of anti-hormonal therapy in women with ovarian cancer.

Autosomal dominant juvenile amyotrophic lateral sclerosis and distal hereditary motor neuronopathy with pyramidal tract signs: synonyms for the same disorder?

Autosomal dominant juvenile amyotrophic lateral sclerosis (ALS) is a rare disorder and so far only one family has been reported. Genetic linkage studies mapped the disease locus to chromosome 9q34 (ALS4). The diagnosis of ALS in this family is based on the clinical signs with almost exclusively lower motor neurone pathology in combination with less prominent pyramidal tract signs. Atypical features include normal life expectancy, the absence of bulbar involvement and the symmetrical distal distribution of atrophy and weakness. We performed a molecular genetic study in three families that we had diagnosed as having distal hereditary motor neuronopathy, i.e. distal spinal muscular atrophy or spinal Charcot-Marie-Tooth syndrome, and found linkage to the ALS4 locus. The clinical phenotype in these three families, of different geographic origin (Austria, Belgium and England), is strikingly similar to the autosomal dominant juvenile ALS family except for a younger onset age in two of the distal hereditary motor neuronopathy families. These data suggest that ALS4 and distal hereditary motor neuronopathy with pyramidal tract signs may be one and the same disorder.

The occurrence and significance of V gene mutations in B cell-derived human malignancy

The classification of B cell tumors has relevance for refining and improving clinical strategies. However, consensus has been difficult to establish, and although a scheme is now available, objective criteria are desirable. Genetic technology will underpin and extend current knowledge, and it is certain to reveal further subdivisions of current tumor categories. The Ig variable region genes of B cell tumors present a considerable asset for this area of investigation. The unique sequences carried in neoplastic B cells are easily isolated and sequenced. In addition to acting as clone-specific markers of each tumor, they indicate where the cell has come from and track its history following transformation. There is emerging clinical value in knowing whether the cell of origin has encountered antigen and has moved from the naive compartment to the germinal center, where somatic mutation is activated. This is amply illustrated by the subdivision of chronic lymphocytic leukemia into two subsets, unmutated or mutated, each with very different prognosis. Other tumors may be subdivided in a similar way. Microarray technology is developing rapidly to probe gene expression and to further divide tumor categories. All these genetic analyses will provide objective data to enhance both our understanding of B cell tumors and our ability to treat them.

Neuroactive steroids and central nervous system disorders

Steroid hormones are vital for the cell life and affect a number of neuroendocrine and behavioral functions. In contrast to their endocrine actions, certain steroids have been shown to rapidly alter brain excitability and to produce behavioral effects within seconds to minutes. In this article we direct attention to this issue of neuroactive steroids by outlining several aspects of current interest in the field of steroid research. Recent advances in the neurobiology of neuroactive are described along with the impact of advances on drug design for central nervous system (CNS) disorders provoked by neuroactive steriods. The theme was selected in association with the clinical aspects and therapeutical potentials of the neuroactive steroids in CNS disorders. A wide range of topics relating to the neuroactive steroids are outlined, including steroid concentrations in the brain, premenstrual syndrome, estrogen and Alzheimer's disease, side effects of oral contraceptives, mental disorder in menopause, hormone replacement therapy, Catamenial epilepsy, and neuractive steroids in epilepsy treatment.

New strategies for vaccination and imunomodulation in NHL

Knowledge of the genetic changes which occur in cancer cells is stimulating research aimed towards new therapies. Immunotherapeutic approaches, particularly antibody therapy, are already finding a place in treatment of hematological malignancies. Vaccination will build on experience in the field of infectious diseases, and it should be possible to design vehicles to deliver the expanding range of tumour antigens to the immune system. For DNA vaccines, fusion genes have the potential to activate and direct immune effector pathways. One candidate antigen for B-cell malignancies is the clonal idiotypic immunoglobulin and we have designed a fusion vaccine encoding idiotypic sequence fused to a sequence from a powerful antigen from tetanus toxin. This promotes protective immunity against lymphoma in models, and is now in clinical trial. One challenge is to bring patients into remission without significant damage to immune capacity. Another is to rethink the nature of clinical trials so that more pilot studies of efficacy can be carried out. There is no evidence so far of toxicity due to injection of DNA, but for antigens which are expressed by normal cells, the line between attack on tumour and autoimmunity will have to be carefully drawn.

Contrasting molecular pathology of colorectal carcinoma in Egyptian and Western patients

Colorectal carcinoma is uncommon in Egypt, but a high proportion of cases occurs before age 40 years and in the rectum. We compared the molecular pathology of 59 representative Egyptian patients aged 10-72 to Western patients with sporadic, young-onset, or hereditary non-polyposis colorectal cancer syndrome (HNPCC)-associated carcinoma and found significant differences. Most Egyptian cancers were rectal (51%) and poorly differentiated (58%). High levels of microsatellite instability (MSI-H) were frequent (37%) and attributable in some cases (36%) to methylation of the promoter of the hMLH1 mismatch repair gene, but no MSI-H cancer had loss of hMSH2 mismatch repair gene product of the type seen with germline hMSH2 mutation in HNPCC. K-ras mutation was uncommon (11%). In subset analyses, high frequencies of MSI-H in rectal carcinomas (36%) and p53 gene product overexpression in MSI-H cancers (50%) were found. MSI-H and K-ras mutation in Egyptians under age 40 were unusual (17% and 0%, respectively), and schistosomiasis was associated with MSI and K-ras mutation. Cluster analysis identified 2 groups: predominantly young men with poorly differentiated mucinous and signet-ring cell colorectal carcinoma lacking K-ras mutation; older patients who had well- or moderately differentiated adenocarcinoma often with MSI-H, K-ras mutation and schistosomiasis. Our findings show that the molecular pathology of colorectal cancer in older as well as younger Egyptians has unique differences from Western patients, and schistosomiasis influences the molecular pathogenesis of some tumours.

Effects of salviainolic acid A (SA-A) on liver injury: SA-A action on hepatic peroxidation

BACKGROUND/AIMS

This study aimed to investigate the actions of salviainolic acid A (SA-A), an antiperoxidative component of Salvia miltiorrhiza (Sm), on rat liver injury and fibrosis.

METHODS

Acute and chronic rat liver injury models were established using carbon tetrachloride (CCl4). After 48 h (acute) or during 6 weeks of CCl4 injection, rats were further divided and treated with biphenyl dimethyl-dicarboxylate (BDD) or colchicine, as a control antifibrotic treatment, with Sm, a herbal compound, or SA-A, a water-soluble extract of Sm. Liver function was investigated by assessing alanine transaminase (ALT) and aspartate transaminase (AST) activities, histological analysis, hydroxyproline (Hyp) and malondiadehyde (MDA) content. In vitro, isolated cultured hepatocytes were injured with CCl4 gas for 24 h, followed by treatment with either vitamin E or various concentrations of SA-A. The extent of hepatocyte injury was monitored by analyzing various lipid peroxidative parameters such as superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), lactase dehydrogenase (LDH), and glutathione peroxidase (GSH-PX) levels in hepatocyte supernatants.

RESULTS

SA-A significantly decreased abnormal serum ALT activity both in acutely and chronically injured rat livers, decreased abnormal serum AST activity, Hyp and MDA content and attenuated hepatic collagen deposition. After CCl4 incubation and injury, the activities of AST, ALT CAT, GSH-PX and LDH and MDA content in hepatocyte supernatants increased significantly, but GSH levels decreased significantly. SA-A markedly improved these pathological changes in a dose-dependent manner. 10(-4) mol/l SA-A had stronger inhibitory action than vitamin E.

CONCLUSIONS

Our studies suggest that SA-A has antiperoxidative effects on injured hepatocytes in liver injury and fibrosis induced by CCl4.

Detection of early atherosclerosis with radiolabeled monocyte chemoattractant protein-1 in prediabeteic Zucker rats

BACKGROUND

Migration of monocytes into the arterial wall is an early finding of atherosclerosis. Monocytes are attracted to sites of vascular endothelial cell injury, the initiating event in the development of atheromatous disease, by a chemokine known as monocyte chemoattractant protein-1 (MCP-1). Injured vascular endothelial and smooth muscle cells selectively secrete MCP-1.

OBJECTIVE

This study was performed to determine if radiolabeled MCP-1 would co-localize at sites of monocyte/macrophage concentration in an experimental model of transplant-induced vasculopathy in diabetic animals.

MATERIALS AND METHODS

Hearts from 3-month-old male Zucker rats, heterozygote (Lean) or homozygote (Fat) for the diabetes-associated gene fa, were transplanted into the abdomens of genetically matched recipients. Lean and Fat animals were then fed normal or high-fat diets for 90 days.

RESULTS

At 90 days significant increases (P < 0.013) of MCP-1 graft uptake were seen at imaging and confirmed on scintillation gamma well counting studies in Lean (n = 5) and Fat (n = 12) animals, regardless of diet, 400 % and 40 %, above control values, respectively. MCP-1 uptake of native and grafted hearts correlated with increased numbers of perivascular macrophages (P < 0.02), as seen by immunostaining with an antibody specific for macrophages (ED 2).

CONCLUSION

Radiolabeled MCP-1 can detect abnormally increased numbers of perivascular mononuclear cells in native and grafted hearts in prediabetic rats. MCP-1 may be useful in the screening of diabetic children for early atherosclerotic disease.

DNA fusion vaccines against B-cell tumors

DNA vaccination is currently being explored as a potential strategy for combatting cancer. However, tumor antigens are often weak and the immune system of patients may be compromised. For B-cell tumors, immunoglobulin idiotypic antigens provide defined targets but are poorly immunogenic. Fusion of a sequence derived from tetanus toxin to the genes encoding idiotypic determinants has proved highly effective in activating protective anti-tumor immunity. DNA fusion vaccines containing immuno-enhancing sequences can augment and direct immune attack on a range of target antigens. Gene-based fusion vaccines offer ease of manipulation and flexible design to activate effective attack on cancer.