ESTABLISHING FREEZE DRYING PROCESS FOR CORTICAL AND CANCELLOUS BONE ALLOGRAFT CUBES

@#Freeze drying is a dehydration method to dry bone under freezing environment, enabling removal of water with no or minimial effects on bone strength and durability. Larger size bones obviously require longer freeze drying time to reduce water content to the required level for long term storage at room temperature. For small size bone cubes or chips, it is a normal practice to pool cortical and cancellous bones for freeze drying. The study was aimed at determining if different type of bones of the same size influence the drying time. Human bone cubes of 10 mm x 10 mm x 10 mm were prepared from cortical bone of tibiae and cancellous bone from femoral heads. The bone cubes were freeze dried to reduce water content to less than 6%. Moisture content was monitored using gravimetric method.Weight and density of cortical bone were significantly higher than cancellous bone despite of having similar small size (p<0.05). Cortical bones (density 2.05 ± 0.35 g/cm3) with initial water content of 10.93% required 5 hours to freeze dry, while cancellous bone cubes (density 0.72 ± 0.44 g/cm3) with initial water content of 78.95% required only 1.87 hours. This study confirmed that the structure hence density of human bone cubes determine the freeze drying time. Therefore in the standard operating procedure for freeze drying of bone allograft cubes, high density cortical bone cubes and low density cancellous bone cubes must be freeze dried separately despite being of similar small size

Relationship between parathyroid hormone and subclinical myocardial dysfunction in patients with severe psoriasis.

BACKGROUND: Psoriasis is associated with an increased risk of cardiovascular disease although the mechanism remains unclear. Recent studies have shown that such patients have a high prevalence of vitamin D (vit-D) deficiency and elevated parathyroid hormone (PTH) level. We hypothesized that vit-D deficiency and/or elevated PTH in psoriasis may contribute to left ventricular (LV) dysfunction. METHODS: Seventy-four patients with severe psoriasis with no known cardiovascular disease and 53 age- and gender-matched controls were recruited. All patients underwent detailed transthoracic echocardiography, including speckle tracking derived strains, and plasma levels of 25-hydoxyvitamin D (25-OHD), PTH and cardiac biomarkers including high sensitive C-reactive protein (hs-CRP), high sensitive troponin I (hs-TNI) and brain natriuretic peptide (BNP) were measured. RESULTS: Despite similar systolic and diastolic LV function, patients with severe psoriasis had impaired LV global longitudinal (-18.1 ± 2.6 vs.-19.6 ± 2.9%, P < 0.01) and circumferential strain (-18.7 ± 3.6 vs. -20.8 ± 4.3%, P < 0.01) compared with controls. Patients with severe psoriasis also had a significantly higher PTH (49.9 ± 18.0 vs. 40.5 ± 15.4 pmol/mL, P < 0.01) and hs-CRP (5.7 ± 6.9 vs. 1.9 ± 2.5 pg/mL, P < 0.01), but similar levels of 25-OHD, hs-TNI and BNP (all P > 0.05) compared with controls. Importantly, PTH level was negatively correlated with LV global longitudinal strain (R = -0.30, P < 0.01); and higher PTH level was independently associated with impaired global LV longitudinal strain (R = -0.33, P = 0.04), independent of cardiovascular risk factors, vit-D status and serum biomarkers. CONCLUSIONS: Severe psoriasis patients had an elevated PTH level and suffered from subclinical LV systolic dysfunction as detected by impaired global LV longitudinal strain. Importantly, a higher PTH level was independently associated with impaired global LV longitudinal strain.

Assessing the susceptibility status of Aedes albopictus on Penang Island using two different assays

Routine surveillance on resistant status of field mosquito populations is important to implement suitable strategies in order to prevent pest outbreaks. WHO test kit bioassay is the most frequent bioassay used to investigate the susceptibility status of field–collected mosquitoes, as it is relatively convenient to be carried out in the field. In contrast, the topical application of active ingredient is less popular in investigating the susceptibility status of mosquitoes. In this study, we accessed the susceptibility status of Aedes albopictus Skuse collected from two dengue hotspots on Penang Island: Sungai Dua and Persiaran Mayang Pasir. Two active ingredients: permethrin and deltamethrin, were used. WHO test kit bioassay showed that both wild strains collected were susceptible to the two active ingredients; while topical application assay showed that they were resistant. This indicated that WHO test kit bioassay less sensitive to low level of resistance compared to topical application assay. Hence, topical application is expected to be more indicative when used in a resistance surveillance programme.

Low-dose terlipressin plus banding ligation versus low-dose terlipressin alone in the prevention of very early rebleeding of oesophageal varices.

BACKGROUND: Very early rebleeding is frequently encountered in patients with acute oesophageal variceal bleeding. A trial was designed to assess the efficacy and safety in patients with no active bleeding at endoscopy, receiving banding ligation association with terlipressin to prevent very early rebleeding. METHODS: Patients with no active variceal bleeding at endoscopy were evaluated. Eligible patients were randomised to receive terlipressin infusion alone for 5 days (Terlipressin group) or banding ligation plus terlipressin infusion for 2 days (Combined group). Primary endpoints were treatment failure and very early rebleeding. RESULTS: The terlipressin group was composed of 46 patients and the Combined group was composed of 47 patients. Both groups were comparable in terms of baseline data. Forty-eight-hour haemostasis was achieved in 91% in the Terlipressin group and 98% in the Combined group (p = 0.20). Very early rebleeding within 48-120 h occurred in 7 patients (15%) in the Terlipressin group but not in any patients (0%) in the Combined group (p = 0.006). Treatment failure was 24% in the Terlipressin group and 2% in the Combined group (p = 0.002). Multivariate analysis revealed that treatment (OR 0.081; 95% CI 0.010 to 0.627) was the only predictive factor of very early rebleeding. Blood requirement was significantly lower in the Combined group than in the Terlipressin group. Complications and 6-week survival were similar in both groups. CONCLUSIONS: Combination of banding ligation and terlipressin infusion for 2 days was superior to only infusion of terlipressin for 5 days in the reduction of very early rebleeding and treatment failure in patients with inactive variceal bleeding at endoscopy. TRIAL REGISTRATION NUMBER: ISRCTN28353453.

A prospective, randomized controlled trial of transjugular intrahepatic portosystemic shunt versus cyanoacrylate injection in the prevention of gastric variceal rebleeding.

BACKGROUND AND STUDY AIMS: Both endoscopic obturation and transjugular intrahepatic portosystemic shunts (TIPSs) have proven to be effective in preventing rebleeding from gastric varices. This study compared the efficacy and complications of these modalities. PATIENTS AND METHODS: Cirrhotic patients with acute bleeding from gastric varices were considered for inclusion. After initial control, eligible patients were randomly allocated to two groups: TIPS (n = 35) and obturation using cyanoacrylate (n = 37). In the cyanoacrylate group, treatment was repeated regularly until gastric varices were obliterated. Patients of both groups received regular follow-up. The end points were gastric variceal rebleeding or death. RESULTS: Stent shunt insertion was successful in all TIPS patients, and mean portal pressure gradient decreased from 21.4 +/- 7.5 mm Hg to 7.5 +/- 3.5 mm Hg ( P < 0.001). Variceal obliteration was achieved in 19 patients in the cyanoacrylate group (51 %) compared with seven TIPS patients (20 %) ( P < 0.02). After a median follow up of 33 months, upper gastrointestinal bleeding occurred in 15 TIPS patients (43 %) and 22 cyanoacrylate patients (59 %) ( P = 0.12). Rebleeding from gastric varices was encountered in four TIPS patients (11 %) and 14 cyanoacrylate patients (38 %) ( P = 0.014; odds ratio 3.6, 95 %CI 1.2 - 11.1). Blood transfusion requirements were lower in the TIPS group than in the cyanoacrylate group ( P < 0.01). Survival and frequency of complications were similar in both groups. CONCLUSIONS: TIPS proved more effective than glue injection in preventing rebleeding from gastric varices, with similar survival and frequency of complications.