Excess hospital admissions for pneumonia, chronic obstructive pulmonary disease, and heart failure during influenza seasons in Hong Kong

It is widely held that Southern China is a hypothetical influenza epicentre for the emergence of pandemic influenza viruses. However, influenza is perceived as a relatively unimportant infection in this part of the world compared with western countries. Hong Kong is situated within the hypothetical epicentre and serves as a sentinel post for the region. In a retrospective study, the influenza-associated excess hospitalisations in a regional hospital for pneumonia, chronic obstructive pulmonary disease (COPD), heart failure, and asthma in persons aged > or = 65 years from 1998 to 2001 were each estimated by a model taking into consideration the confounding effect of other respiratory viral infections, seasonal factors, time trends, and weather and pollution indices. In the regression models, influenza activity is an independent significant factor affecting admission rates for pneumonia, COPD, and heart failure but not that for asthma. The variations in hospital admissions for pneumonia, COPD, and heart failure explained by influenza activity were 38.9, 7.5, and 45.6%, respectively. The adjusted rates of excess influenza-associated hospital admissions for the three diagnoses combined amounted to 58.5, 20.0, 29.2, and 13.4 per 10,000 populations aged > or = 65 years in 1998, 1999, 2000, and 2001, respectively. In conclusion, influenza activity is associated significant excess hospital admissions among elderly aged 65 or above in Hong Kong, comparable to the data reported in Western countries. The findings support a wider application of annual influenza vaccination in this region.     

Primary cultures of rat astrocytes respond to thiamine deficiency-induced swelling by downregulating aquaporin-4 levels

Imaging studies indicate that cerebral edema is an important consequence of Wernicke's encephalopathy (WE), a disorder caused by thiamine deficiency (TD). We have investigated this problem using a recently developed in vitro astrocyte model of TD. Measurement of cell volume using the 3-O-methylglucose uptake method revealed a dose-dependent swelling of astrocytes during exposure to TD conditions. Time course studies indicated a progressive volume increase up to a maximum of 93% above controls after 4 days of treatment. This swelling then partially resolved, and remained stable for up to 10 days following commencement of TD treatment. Measurement of aquaporin-4 (AQP-4) levels showed a 44% loss after 10 days and a temporal profile consistent with an important role for this water channel protein in astrocyte cell volume changes during TD. Our findings of astrocyte swelling in TD are consistent with previous reports of focal brain edema in cases of WE, and indicate that AQP-4 may be an important target for ameliorating some of the clinical problems associated with this disorder.     

Superior osteogenic capacity for bone tissue engineering of fetal compared with perinatal and adult mesenchymal stem cells

Mesenchymal stem cells (MSCs) from human adult bone marrow (haMSCs) represent a promising source for bone tissue engineering. However, their low frequencies and limited proliferation restrict their clinical utility. Alternative postnatal, perinatal, and fetal sources of MSCs appear to have different osteogenic capacities, but have not been systematically compared with haMSCs. We investigated the proliferative and osteogenic potential of MSCs from human fetal bone marrow (hfMSCs), human umbilical cord (hUCMSCs), and human adult adipose tissue (hATMSCs), and haMSCs, both in monolayer cultures and after loading into three-dimensional polycaprolactone-tricalcium-phosphate scaffolds.Although all MSCs had comparable immunophenotypes, only hfMSCs and hUCMSCs were positive for the embryonic pluripotency markers Oct-4 and Nanog. hfMSCs expressed the lowest HLA-I level (55% versus 95%-99%) and the highest Stro-1 level (51% versus 10%-27%), and had the greatest colony-forming unit-fibroblast capacity (1.6x-2.0x; p < .01) and fastest doubling time (32 versus 54-111 hours; p < .01). hfMSCs had the greatest osteogenic capacity, as assessed by von-Kossa staining, alkaline phosphatase activity (5.1x-12.4x; p < .01), calcium deposition (1.6x-2.7x in monolayer and 1.6x-5.0x in scaffold culture; p < .01), calcium visualized on micro-computed tomography (3.9x17.6x; p < .01) and scanning electron microscopy, and osteogenic gene induction. Two months after implantation of cellular scaffolds in immunodeficient mice, hfMSCs resulted in the most robust mineralization (1.8x-13.3x; p < .01).The ontological and anatomical origins of MSCs have profound influences on the proliferative and osteogenic capacity of MSCs. hfMSCs had the most proliferative and osteogenic capacity of the MSC sources, as well as being the least immunogenic, suggesting they are superior candidates for bone tissue engineering.     

Synovial sarcoma in older patients: clinicopathological analysis of 32 cases with emphasis on unusual histological features

AIMS: To analyse the clinicopathological features of synovial sarcoma presenting in patients over 60 years of age, an uncommon subset which have not been specifically studied. METHODS AND RESULTS: Thirty-two cases of primary synovial sarcoma in patients aged > or =60 years were retrieved from the authors' consultation files. These were analysed histologically and immunohistochemically and clinical follow-up was obtained in 26 cases (median duration 41 months). Mean age at diagnosis was 71.6 years (range 60-84) with 19 females and 13 males. Anatomical sites were lower limb (n = 13), upper limb (n = 5), lung/pleura (n = 5), trunk (n = 4), head/neck (n = 3), mediastinum (n = 1) and scrotum (n = 1). Histologically, 23 were monophasic and nine were biphasic; 14 were poorly differentiated, of which five showed focally marked pleomorphism. Unusual features in two cases each included organoid nodules, granular cell change, squamous metaplasia and papillary architecture. Ten patients developed local recurrence and 11 developed metastases, of whom seven died. Large tumour size, poorly differentiated morphology and high mitotic rate correlated with poor outcome. CONCLUSIONS: Less than 10% of synovial sarcomas occur in patients over 60, in which age group this diagnosis is often not considered. Despite inevitable bias in consultation material, it seems that these cases, when compared with younger age groups, more often show poorly differentiated histology and more often develop at unusual locations.     

A case of primary esophageal B-cell lymphoma of MALT type,presenting as a submucosal tumor

The primary esophageal lymphoma is extremely rare, and shows various morphologic characteristics. Only a single case of mucosa-associated lymphoid tissue (MALT) type lymphoma confined to the esophagus has been reported in the literature. A 61-yr-old man was referred to our hospital for evaluation of an esophageal submucosal tumor (SMT) that had been detected incidentally by endoscopy. He had a history of pulmonary tuberculosis with long-term anti-tuberculosis medication 15 yr before, and also had a history of syphilis, which had been treated one year before. He had been taking a synthetic thyroid hormones for the past 10 months because of an autoimmune thyroiditis. Endoscopy showed a longitudinal round and tubular shaped smooth elevated lesion, which was covered with intact mucosa and located at the mid to distal esophagus, 31 cm to 39 cm from the incisor teeth. Endoscopic ultrasonography (EUS) showed a huge longitudinal growing intermediate- to hypo-echoic mass located in the submucosal layer with internal small, various sized honeycomb-like anechoic lesions suggesting germinal centers. Subsequently, he underwent a surgery, which confirmed the mass as a primary esophageal low-grade B-cell lymphoma of MALT type.     

Mollaret's meningitis: cytopathologic analysis of fourteen cases

Mollaret's meningitis (MM) is a rare disease of benign nature characterized by recurrent episodes of aseptic meningitis. Cerebrospinal fluid (CSF) examination remains the sole diagnostic modality. Eighteen CSF samples from 14 patients were studied along with the clinical data. Specimens were prepared by cytocentrifugation and Millipore filtration and were stained with Diff-Quik and Papanicolaou stains. Eight patients were men and six were women, with an age range of 17-74 yr (mean age 37 yr). Most common clinical presentation was recurrent episodes of headaches and photophobia followed by a sustained mild fever lasting 5-7 days. The CSF showed markedly increased cellularity with pleocytosis. The differential count showed predominant monocytosis ranging from 84% to 100% (mean 96). In our series, two patients had herpes simplex virus type 2 (HSV-2) DNA detected by polymerase chain reaction (PCR) in the CSF. The monocytes were seen predominantly singly, but three cases showed a strong tendency to aggregate in small groups. Phenotypically, these cells had bean-shaped bilobed nuclei as well as multiple deep nuclear clefts depicting the so-called "footprint" appearance. In four cases, multiple blunt-tipped cytoplasmic pseudopods were noted. Degenerated monocytes with the appearance of the so-called "ghost cells" were noted in one-half of the cases. Background cells were mostly small mature lymphocytes; however, one-half of cases showed a significant amount of plasma cells and/or polymorphonuclear leukocytes (PMNs). Lysed blood with hemosiderin-laden macrophages and numerous leptomeningeal cells were seen in two cases. CSF examination of MM presents a spectrum of cytomorphologic features. When interpreted in light of the appropriate clinical setting. the latter, although nonspecific, provides an accurate diagnosis. The differential diagnosis includes various degenerative, inflammatory/infectious, and lymphoproliferative disorders of the central nervous system.