Gelatin methacrylate/carboxybetaine methacrylate hydrogels with tunable crosslinking for controlled drug release

In this work, methacrylated gelatin (GelMA) based hydrogels were fabricated with carboxybetaine methacrylate (CBMA) to manipulate the properties of the gelatin-based hydrogels, since CBMA is a much smaller compound compared to gelatin. With the incorporation of CBMA, these hydrogels demonstrated better mechanical properties, a slower degradation rate, and a controlled drug release rate compared with the GelMA alone group. GelMA/CBMA hydrogels also showed good cell viability. As in the in vivo test, vascular endothelial growth factor (VEGF)-loaded GelMA/CBMA hydrogels displayed certain degrees of angiogenesis. These results indicate that GelMA/CBMA hydrogels are biocompatible, and the properties of GelMA/CBMA hydrogels can be easily tuned with the ratio of CBMA. These characteristics make the GelMA/CBMA hydrogel a promising material for drug delivery and tissue engineering.

Faecal occult blood screening: knowledge, attitudes, and practice in four Hong Kong primary care clinics

OBJECTIVES. To assess primary care patients for their awareness, knowledge, and attitude towards colorectal cancer and screening, to report on the uptake of faecal occult blood test screening and the results of screening, and explore predictors of screening uptake. DESIGN. Cross-sectional study. SETTING. Four primary care clinics in Hong Kong. PATIENTS. A total of 1664 patients aged 50 to 74 years attending the clinics in the period July 2006 to July 2007. MAIN OUTCOME MEASURES. Percentage of subjects who were aware that colorectal cancer is common and curable at an early stage, and who knew that faecal occult blood test or colonoscopy is useful for screening; relevant knowledge score; uptake rate of faecal occult blood testing; rate of testing positive; and factors predicting uptake. RESULTS. A total of 1645 questionnaires were collected. In all, 89% (95% confidence interval, 88-91%) were aware that colorectal cancer is common, 95% (94-96%) believed faecal occult blood test and colonoscopy are useful for screening, and 58% (56-61%) achieved a knowledge score of 50% or above. The uptake rate of the faecal occult blood test was 35%. Uptake was higher among those with a positive family history (odds ratio=1.57; 95% confidence interval, 1.08-2.27; P=0.02), those who were more aware that colorectal cancer is common (1.86; 1.29-2.69; P=0.001), and that colorectal cancer is potentially curable at an early stage (1.76; 1.32-2.36; P=0.0001). Rate of testing positive was 2.1% (95% confidence interval, 0.9-3.3%); no colorectal cancer was detected and the neoplasia detection rate (for cancers and adenomas) was 5.1 per 1000 subjects screened. CONCLUSIONS. Patients were aware that colorectal cancer is common in our community, and faecal occult blood test or colonoscopy is useful for screening. The uptake of screening was low, though relatively higher for those with a positive family history and greater awareness of the high frequency and potential for cure of colorectal cancer. Faecal occult blood test positivity rate was 2.1%, and neoplasia detection rate 5.1 per 1000 screened.

Biocompatibility of Fe(3)O(4) nanoparticles evaluated by in vitro cytotoxicity assays using normal, glia and breast cancer cells

In order to reveal the biocompatibility of Fe(3)O(4) nanoparticles and bipolar surfactant tetramethylammonium 11-aminoundecanoate cytotoxicity tests were performed as a function of concentration from low (0.1 microg ml(-1)) to higher concentration (100 microg ml(-1)) using various human glia, human breast cancer and normal cell lines. Cytotoxicity tests for human glia (D54MG, G9T, SF126, U87, U251, U373), human breast cancer (MB157, SKBR3, T47D) and normal (H184B5F5/M10, WI-38, SVGp12) cell lines exhibited almost nontoxicity and reveal biocompatibility of Fe(3)O(4) nanoparticles in the concentration range of 0.1-10 microg ml(-1), while accountable cytotoxicity can be seen at 100 microg ml(-1). The results of our studies suggest that Fe(3)O(4) nanoparticles coated with bipolar surfactant tetramethylammonium 11-aminoundecanoate are biocompatible and promising for bio-applications such as drug delivery, magnetic resonance imaging and magnetic hyperthermia.

Epidemiological study of diabetic retinopathy in a primary care setting in Hong Kong

OBJECTIVES

To estimate the prevalence and risk factors of diabetic retinopathy in type 2 diabetic patients, and to investigate the difference in retinopathy progression in patients with normal fundi or established retinopathy at baseline and the risk factors implicated in the progression.

DESIGN

Retrospective community-based study.

SETTING

Ten primary care clinics in Hong Kong.

PATIENTS

Type 2 diabetic patients; subsidiary analysis included subjects with more than one screening event.

MAIN OUTCOME MEASURES

Patient demographics, baseline prevalence, and risk factors of diabetic retinopathy; progression of retinopathy in patients with normal fundi and established retinopathy at baseline, and the associated risk factors.

RESULTS

A total of 6165 patients were recruited from January 1998 to May 2004. Primary analysis included 4423 patients with good-quality retinal photographs. The mean age of the patients was 60.36 years (standard deviation, 10.80 years; range, 28-94 years), the mean duration of diabetes was 4.71 years (standard deviation, 4.67 years; range, 0.1-40.6 years), and the mean level of glycated haemoglobin was 7.47% (standard deviation, 1.44%). The prevalence of retinopathy at baseline was 28.4%. Subsidiary analysis showed progression to sight-threatening retinopathy was more common in the group with baseline retinopathy than that without (7.9% vs 0.7%), and occurred at a faster rate (mean, 1.5 [range, 0.5-3.0] vs 2.0 [1.0-4.2] years). Logistic regression revealed that the level of glycated haemoglobin was positively associated with both the onset (P<0.001) and progression of retinopathy (P=0.03).

CONCLUSION

Optimal glycaemic control is important for reducing sight-threatening retinopathy. Close observation is required for patients with established retinopathy as progression occurs more rapidly.

The prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting: cross-sectional study

OBJECTIVES

To determine the prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting, and to study the association between various risk factors and the presence of microalbuminuria.

DESIGN

Cross-sectional community-based study.

SETTING

Four primary care clinics, Hong Kong.

PATIENTS

All patients with type II diabetes mellitus who regularly attended the clinics between May 2002 and March 2003.

MAIN OUTCOME MEASURES

Patients' demographic data, the proportion with microalbuminuria (measured using a spot urine test), and the association between this condition and risk factors for diabetic nephropathy (via correlation and multivariable logistic regression analysis).

RESULTS

The mean age of the 1161 patients in the sample population was 58.0 years. The mean duration of diabetes mellitus was 5.7 years, and the mean level of glycated haemoglobin was 7.4%. A total of 13.4% of the patients had microalbuminuria. Having the condition was significantly associated with advanced age, female sex, poor glycaemic control, and coexisting hypertension in both correlation and regression analyses. No significant association with ever smoking was found.

CONCLUSION

Early screening for incipient diabetic nephropathy and aggressive management of modifiable risk factors in a primary care setting may be important in optimising the renal outcome of patients with type II diabetes mellitus.

Rectal cancer mortality and total hardness levels in Taiwan's drinking water

The possible association between the risk of rectal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible rectal cancer deaths (986 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (986 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and rectal cancer mortality. Odds ratio and 95% confidence intervals were 1.24 (1.01-1. 55) and 1.38 (1.10-1.73), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for rectal cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.

Effects of indoor environmental factors on risk for acute otitis media in a subtropical area

The objective of this study was to examine the relationship between indoor environmental factors and acute otitis media in a subtropical area. A case-control study was performed using participants from a prevalence survey that included 219 school children with acute otitis media and 219 age- and gender-matched controls. The study was confined to 4164 primary school children aged 6-12 yr attending 8 primary schools in Kaohsiung rural municipalities who participated in a prevalence study of the health effects of an indoor environment. An acute otitis media case was defined as a child with acute symptoms (presenting with earache, fever, irritability, and/or discharge from the ear) diagnosed by a physician in the previous year. Controls selected from the same school did not have chronic or acute respiratory illness or an ear-related illness during the same period. Information regarding the home environment was obtained using a structured written questionnaire, completed by the parents of the children. Of the many indoor environmental factors included in this study, only living in a home with indications of dampness (mold, flooding, home dampness) showed an association with acute otitis media. It was concluded that dampness in the home is a new public health issue in subtropical areas.

Different regulation of the human thymidine kinase promoter in normal human diploid IMR-90 fibroblasts and HeLa cells

Transcriptional activation of the human thymidine kinase (hTK) promoter plays an important role in the cell cycle control of thymidine kinase expression. Using the luciferase reporter cotransfection assay, we found that the activity of the hTK promoter in IMR-90 normal human diploid fibroblasts was increased by the constitutively over-expressed cyclin A or cyclin E but not by cyclin D, suggesting that the former two cyclins may act as positive regulators for the hTK promoter. The sequence responsible for the transcriptional activation by cyclin E was identified to be located between -133 and -92 of the hTK promoter. Regulation of the hTK promoter in HeLa cells appeared to be different from that in IMR-90 fibroblasts. Firstly, the hTK promoter in HeLa was already highly activated and could not be further activated by ectopically expressed cyclin A or E. Secondly, the -133 to -92 region of the hTK promoter was important for the promoter strength in HeLa cells but not in IMR-90 cells. The steady-state levels of cyclins A and E were readily detected in HeLa cells but not in normal IMR-90 fibroblasts. Based on these results, we propose that the cellular environment of the HeLa cell allows the hTK promoter to stay fully activated for transcription regardless of ectopically expressed cyclin A or E and that transcriptional activation of thymidine kinase gene is deregulated in these tumor cells.