TNFalpha induces NFkappaB/p50 in association with the growth and morphogenesis of normal and transformed rat mammary epithelial cells.

In contrast to the cytotoxic or cytostatic effect of TNFalpha on many breast cancer cell lines, TNFalpha stimulates growth and morphogenesis of normal rat mammary epithelial cells (MEC). The present studies were carried out to determine whether there are intrinsic differences between normal and malignant MEC which may explain the differing responsiveness to TNFalpha. Freshly isolated rat MEC organoids from normal mammary gland or 1-methyl-1-nitrosourea-induced mammary tumors were treated with TNFalpha for 21 days.

Functional role of matrix metalloproteinases (MMPs) in mammary epithelial cell development.

The extracellular matrix (ECM) is an important regulator of mammary epithelial cell (MEC) function and is remodeled by matrix metalloproteinases (MMPs). To investigate the significance and regulation of MMP activity in normal MEC, we utilized a primary culture model in which rat MEC were grown three dimensionally within a reconstituted basement membrane (RBM) in defined serum-free medium. Zymograms of culture medium demonstrated that five major gelatinases of 97, 80, 74, 69, and 65 kDa were secreted by MEC and were distinct from gelatinases of RBM origin.

Regulation of milk protein gene expression in normal mammary epithelial cells by tumor necrosis factor.

Tumor necrosis factor-alpha (TNF) is a physiologically significant regulator of mammary gland development, stimulating growth and branching morphogenesis of mammary epithelial cells (MEC) and modulating functional differentiation. The present studies were performed to determine the mechanism by which TNF modulated functional differentiation. In rat MEC in primary culture, TNF inhibited accumulation of whey acidic protein and beta-casein messenger RNAs in a time- and concentration-dependent manner.

Increasing use of inhaled steroids associated with declining asthma mortality.

Increasing worldwide asthma prevalence and mortality has led to greater advocacy of inhaled agents, especially steroids. To determine whether corresponding drug usage trends had ensued locally, wholesale data (expressed as defined daily doses (DDDs)/1000 inhabitants/day) were compared for inclusive periods 1984-1986 and 1992-1994. Whereas absolute usage of anti-asthmatics increased by 79%, proportional inhaled usage increased markedly, especially of steroids (571%) and in hospitals.

Macrolide resistance in Streptococcus pneumoniae in Hong Kong.

Erythromycin resistance rates among penicillin-susceptible Streptococcus pneumoniae were 38 and 92% among penicillin-intermediate and -resistant S. pneumoniae isolates from Hong Kong, respectively, and 27% (43 of 158) of the isolates showed the MLS(B) phenotype, and the majority carried the ermB gene; 73% (115 of 158) displayed the M phenotype, and all possessed the mef gene. The MLS(B) phenotype was predominant in penicillin-susceptible, macrolide-resistant isolates and in penicillin-nonsusceptible isolates of serotype 6B, whilst the M phenotype was predominant in penicillin-intermediate or -resistant isolates belonging to serotype 23F or 19F.

Differential expression of integrin mRNAs and proteins during normal rat mammary gland development and in carcinogenesis.

A rat model was used to address the roles of integrins in the regulation of normal mammary epithelial cell (MEC) growth and differentiation and in mammary carcinogenesis. The expression of integrins alpha5, alpha6, beta1, and beta4 was examined via Northern and Western blotting analyses in freshly isolated MEC from various postnatal developmental stages. mRNAs for all four integrins were detectable at puberty and were increased during pregnancy.

Mammary fibroblasts stimulate growth, alveolar morphogenesis, and functional differentiation of normal rat mammary epithelial cells.

Stromal-epithelial interactions play a profound role in regulating normal and tumor development in the mammary gland. The molecular details of these events, however, are incompletely understood. A novel serum-free transwell coculture system was developed to study the natural paracrine interactions between mammary epithelial cells (MEC) and mammary fibroblasts (MFC) isolated from normal rats during puberty.

Patterns of antibiotic resistance, serotype distribution, and patient demographics of Streptococcus pneumoniae in Hong Kong.

Streptococcus pneumoniae isolates from clinical specimens during the period 1993-1997 at the Prince of Wales Hospital, Hong Kong, were analysed by the antibiotic resistance profiles, the distribution of serotypes, specimen types, and patient demographics. 1,229 non-duplicate S. pneumoniae isolates were evaluated; 84% from the respiratory tract, 11% from blood and cerebrospinal fluid and the remainder from body fluids and pus swabs.

A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong.

Background: Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong.

Methods: Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned.

A developmental atlas of rat mammary gland histology.

The mammary gland is a dynamic tissue that undergoes epithelial expansion and invasion during puberty and cycles of branching and lobular morphogenesis, secretory differentiation, and regression during pregnancy, lactation, and involution. The alteration in the mammary gland epithelium during its postnatal differentiation is accompanied by changes in the multiple stromal cell types present in this complex tissue. The postnatal plasticity of the epithelium, endothelium, and stromal cells of the mammary gland may contribute to its susceptibility to carcinogenesis.

Circulating nitric oxide is suppressed in obstructive sleep apnea and is reversed by nasal continuous positive airway pressure.

Epidemiological studies have implicated obstructive sleep apnea (OSA) as an independent comorbid factor in cardiovascular and cerebrovascular diseases. The recurrent episodes of occlusion of upper airways during sleep result in pathophysiological changes that may predispose to vascular diseases, and we postulate that nitric oxide may be one of the mediators involved. This study investigates the levels of circulating nitric oxide (NO), measured as serum nitrites and nitrates, in the early morning in OSA subjects compared with control subjects, and the effect of overnight nasal continuous positive airway pressure (nCPAP) in OSA subjects.

Up-regulation of circulating adhesion molecules in bronchiectasis.

Adhesion molecules are expressed on the surface of endothelial cells and leukocytes and are responsible for mediating the migration of intravascular leukocytes into inflamed tissue. Intensive recruitment of neutrophils into the airways occurs in bronchiectasis, although little is known about the role of adhesion molecules in this process. The authors, therefore, determined serum levels of E-selectin, intercellular adhesion molecule (ICAM)-1 and vascular adhesion molecule (VCAM)-1 in stable bronchiectasis patients (n=37) and healthy control subjects (n=17), and evaluated their relationship with clinical markers of disease severity in bronchiectasis.

Computed tomographic cephalometric analysis of Chinese patients with obstructive sleep apnoea.

Variations of craniofacial and upper airway structures are recognized to contribute to the phenomenon of obstructive sleep apnoea (OSA). Most previous cephalometric studies were performed using erect lateral radiographs in Caucasian patients. The present project aims to determine cephalometric measurements, utilizing CT, in normal Chinese subjects and in Chinese patients with OSA.

Neutrophil-mediated degradation of lung proteoglycans: stimulation by tumor necrosis factor-alpha in sputum of patients with bronchiectasis.

Neutrophil-mediated degradation of bronchial matrix has been proposed as a pathogenetic factor in bronchiectasis. We hypothesize that neutrophils, found in abundance in the bronchial lumens of patients with bronchiectasis, are capable of degrading lung matrix proteoglycans and that proinflammatory mediators in bronchial secretions of these patients can enhance the degradative action of neutrophils. We used rat bronchoalveolar proteoglycans entrapped in polyacrylamide gel beads as a substrate for test incubations with neutrophils from healthy volunteers and sputum sol from patients with idiopathic bronchiectasis.

Rapid identification of medically important Candida to species level by polymerase chain reaction and single-strand conformational polymorphism.

Invasive fungal disease has taken a great toll on immunocompromised patients. With the emergence of fluconazole and amphotericin B resistance, the rapid identification of fungi to species level is of clinical relevance in guiding appropriate antifungal therapy. Among these opportunistic fungi, Candida species are the most commonly encountered.

Coagulation and cytokine profile after major hepatobiliary surgery in Chinese patients.

Background/aims: Hypercoagulability and increased circulating cytokine levels have been separately reported after surgical operations. We investigated whether the cytokine level and postoperative coagulation profile would change similarly in Chinese patients undergoing major hepatobiliary surgery.

Methodology: Serial serum levels of IL-6, IL-1 beta and TNF-alpha were measured by colorimetric ELISA.

Functional significance of MMP-9 in tumor necrosis factor-induced proliferation and branching morphogenesis of mammary epithelial cells.

Tissue remodeling is a key process involved in normal mammary gland development, with matrix metalloproteinases (MMPs) playing an important role in this process. Our laboratory has demonstrated that tumor necrosis factor (TNF) stimulates branching morphogenesis of mammary epithelial cells (MEC) within a reconstituted basement membrane. Studies were therefore undertaken to determine whether MMPs might mediate the effects of TNF.

Serum leptin and vascular risk factors in obstructive sleep apnea.

Study Objectives: To define the metabolic profile relevant to vascular risks in obstructive sleep apnea (OSA) and the role of leptin resistance in this risk profile.

Design: Case control study.

Setting: Sleep Laboratory, Queen Mary Hospital, University of Hong Kong, China.

Group B streptococcal meningitis in adults: recent increase in Southeast Asia.

Background: Meningitis caused by Streptococcus agalactiae (Group B Streptococcus) is rare in adults and usually affects patients with predisposing conditions.

Aims: To describe an increase in adult group B streptococcal meningitis occurring in parallel in Hong Kong and Singapore.

Methods: All cases of bacterial meningitis admitted to the Prince of Wales Hospital, Hong Kong and Singapore General Hospital in 1998, aged 15 years or above, were reviewed.

Lung function reference values in Chinese children and adolescents in Hong Kong. II. Prediction equations for plethysmographic lung volumes.

As part of a comprehensive evaluation of lung function in Hong Kong Chinese children and adolescents, over a thousand healthy subjects aged 7-19 yr from seven schools were recruited for lung function testing that included spirometry and, in many cases, lung subdivision measurements. Lung function tests were performed using SensorMedics Automated Body Plethysmograph according to published standards. Of these, 551 subjects (219 males), aged 8-19 yr, had satisfactory lung subdivision indices recorded.

Lung function reference values in Chinese children and adolescents in Hong Kong. I. Spirometric values and comparison with other populations.

As part of a comprehensive evaluation of lung function in Hong Kong-born Chinese children and adolescents, this study was conducted to determine updated prediction equations for spirometry, to evaluate the secular changes of lung function during the past decade, and to compare these results with other data sets. The results are based on 852 (392 male, 460 female) healthy students, age 7 to 19 yr, recruited from seven schools in Hong Kong. All were born and lived in Hong Kong, nonsmokers, free from past or present symptoms or diseases affecting the respiratory tract.

Induction of apoptosis by conjugated linoleic acid in cultured mammary tumor cells and premalignant lesions of the rat mammary gland.

Conjugated linoleic acid (CLA) is an effective agent in preventing mammary cancer in rats treated with a carcinogen. The appearance of a tumor mass is the net result of cell proliferation minus cell death. Thus, apoptosis could be an important mechanism in controlling clonal expansion of the early premalignant lesions.