Identification of skin bacterial profiles of early deceased bodies and the relation to post-mortem interval.

Post-mortem microbiology (PMM) is an important tool in identifying possible causes of sudden unexpected death, as an infectious cause is highly suspected. However, contamination is a major problem in microbiology, and this has increased the difficulty determining the true pathogen that contributes to death in post-mortem cases. Skin commensals are common contaminants in blood cultures. This study was conducted to investigate the skin flora on early deceased bodies and observe the bacteria detected at different post-mortem intervals (PMIs). As blood is usually drawn from the neck and femoral sites for PMM examination, the two body sites were chosen as the sampling sites. Skin swab samples from the neck and femoral (n=80) of each early deceased body were collected by sterile cotton swabs. DNA was extracted from the swabs and then subjected to high-throughput 16S rRNA sequencing by using the Illumina MiSeq platform. Staphylococcus was found to be the most dominant genus in both neck and femoral sites. LEfSe results showed that Cutibacterium is significantly different at the neck site while Corynebacterium is more abundant at femoral site. There are significant differences at genus level between PMI<5H and PMI>5H at both neck and femoral sites. The findings of the present study may act as a reference for microbiologists and forensic pathologists when mixed growth or contamination occurs in post-mortem blood cultures.

An acute infusion of lactic acid lowers the concentration of potassium in arterial plasma by inducing a shift of potassium into cells of the liver in fed rats.

BACKGROUND: Potassium (K(+)) input occurs after meals or during ischemic exercise and is accompanied by a high concentration of L-lactate in plasma (P(L-lactate)). METHODS: We examined whether infusing 100 µmol L-lactic acid/min for 15 min would lead to a fall in the arterial plasma K(+) concentration (P(K)). We also aimed to evaluate the mechanisms involved in normal rats compared with rats with acute hyperkalemia caused by a shift of K(+) from cells or a positive K(+) balance. RESULTS: There was a significant fall in P(K) in normal rats (0.25 mM) and a larger fall in P(K) in both models of acute hyperkalemia (0.6 mM) when the P(L-lactate) rose. The arterial P(K) increased by 0.8 mM (p < 0.05) 7 min after stopping this infusion despite a 2-fold rise in the concentration of insulin in arterial plasma (P(Insulin)). There was a significant uptake of K(+) by the liver, but not by skeletal muscle. In rats pretreated with somatostatin, P(Insulin) was low and infusing L-lactic acid failed to lower the P(K). CONCLUSIONS: A rise in the P(L-lactate) in portal venous blood led to a fall in the P(K) and insulin was permissive. Absorption of glucose by the Na(+)-linked glucose transporter permits enterocytes to produce enough ADP to augment aerobic glycolysis, raising the P(L-lactate) in the portal vein to prevent postprandial hyperkalemia.

Metabolic syndrome attenuates effect of chronic kidney disease on prevalence of coronary disease in men referred for stress imaging study.

BACKGROUND: Metabolic syndrome (MS) and chronic kidney disease (CKD) are both strongly associated with coronary artery disease (CAD). Components of MS also cause CKD. The incremental effect of CKD on CAD prevalence in MS patients referred for stress imaging studies is unknown. METHODS: From January to December 2005, consecutive subjects referred for a stress imaging study were prospectively enrolled. CAD was defined as fixed or reversible defects on nuclear imaging and as resting or stress-induced wall motion abnormalities on echocardiography. MS was defined using NCEP-ATP III criteria. CKD definition was based on calculated glomerular filtration rate. The independent effect of CKD on stress results was assessed using multiple variable logistic regression. Stepwise model selection was used for variable reduction, and areas under the receiver operating characteristic curves (ROC) were calculated. RESULTS: Of 1,122 patients enrolled (mean age 61.4 years, 97% male), 535 (47%) had MS. Among MS patients, 156/535 (29%) had CKD while 116/587 (19%) subjects without MS had CKD. Subjects with CKD were older (p < 0.001) in subjects with and without MS. The presence of CKD affected prevalence of CAD in the non-MS group only, almost doubling it (20% vs. 38%, p < 0.001). Further, using the ordered nature of the 5 CKD stages, worsening severity of CKD had greater prevalence of CAD, in non-MS subjects only (p < 0.001). CONCLUSIONS: MS attenuates the effect of CKD on CAD prevalence, regardless of CKD severity. CKD almost doubles the prevalence of CAD in non-MS subjects. CKD severity is associated with greater CAD burden in the non-MS group.

Cell-culture-based immunochromatography for rapid detection of group A human rotaviruses in aquatic environments.

In an effort to detect rapidly and conveniently the infectious waterborne group A human rotaviruses that cause diarrhea in infants and children, the authors developed the first-ever cell-culture-based immunochromatography method. An immunochromatography kit interacted only with the human rotaviruses VP6 antigen, and the cell-culture-based immunochromatography detected group A human rotaviruses with a sensitivity as low as 1.99 TCID50 ml(-1). This detection sensitivity was similar to that of the cytopathic effect-based method. There were no actual differences between the sensitivity of this method and that of the real-time reverse transcription polymerase chain reaction method, which is known as a method with a relatively high sensitivity. Furthermore, while cell culture detection methods, that is total culturable virus assay, can determine only the presence of infectious waterborne viruses, the cell-culture-based immunochromatography is advantageous for the accurate detection of group A human rotaviruses. Compared with the real-time reverse transcription polymerase chain reaction method, the cell-culture-based immunochromatography is advantageous because it requires a relatively simple process that enables easy quality controls and low test costs. Thus, this study proposed a new method for the identification of group A human rotaviruses, and it is suggested that this cell-culture-based immunochromatography may be applied to detect group A human rotaviruses in aquatic environments.

Secular trend for mortality from breast cancer and the association between diabetes and breast cancer in Taiwan between 1995 and 2006.

AIMS/HYPOTHESIS: Studies have identified an association between diabetes and breast cancer in postmenopausal women in Western countries. Such an association needs to be confirmed in an Asian population. The aim of this study was to evaluate the secular trend for breast cancer mortality in Taiwanese women in the general population and the mortality rate ratios between diabetic patients and the general population. METHODS: Age-specific mortality rates for the general population, categorised into groups aged 25-54, 55-64, 65-74 and > or =75 years, were calculated for the years between 1995 and 2006 (inclusive) from vital statistics published by the Taiwanese government. Linear regression was used to test the trends. A total of 131,573 diabetic women aged > or =25 years from a national cohort recruited between 1995 and 1998 (inclusive) were followed prospectively for vital status, determined from the National Register of Deaths. Mortality rates and mortality rate ratios (mortality rate in diabetic women vs the average and highest mortality rates for the general population) were calculated. RESULTS: A total of 14,230 women aged > or =25 years in the general population died of breast cancer between 1995 and 2006. A trend for an increase in the annual rate was observed for all age groups. A total of 482 diabetic women died of breast cancer, with a crude mortality rate of 45.7 per 100,000 person-years. Compared with the general population the relative risk of mortality for those with diabetes ranged from 1.37 (for the group aged 55-64 years) to 2.43 (for the group aged 25-54 years). CONCLUSIONS/INTERPRETATION: We identified a secular trend of an increase in the rate of breast cancer mortality in the Taiwanese general population. Our data suggest a higher risk of breast cancer mortality in diabetic patients in all age groups.

Numerical study of the influence of anastomotic configuration on hemodynamics in miller cuff models.

Enhanced hemodynamics via geometric alteration is believed to play a role in the favorable redistribution of intimal hyperplasia (IH) in infragenicular supplementary vein cuffs. We aimed to elucidate the consequence of altering geometric configuration in anastomotic hemodynamics in cuff models. A well-validated numerical scheme was used to simulate pulsatile flows in three cuffed anastomotic models with length-to-height ratio (LHR) of 1.4, 2.2 and 3.2, and a St. Mary's boot with LHR of 2.2 at a mean flow rate of 130 mL/min. Characteristic flow patterns and wall shear stress (WSS) distributions were compared. A cohesive vortex is only present in the cuff of LHR = 1.4 and in the boot. The vortex in the cuffs becomes increasingly disorganized with increasing cuff LHR. The area of flow separation at the graft toe, prominent in the cuff of LHR = 3.2, is significantly reduced in the cuff of LHR = 1.4 and eliminated in the boot. All cuffs are characterized by flow separation, flow reversal and a sharp drop in WSS immediately distal to the cuff toe, phenomena not observed in the boot. The cuff configuration, specifically the LHR, is critical in controlling local hemodynamics. A large LHR could lead to reduced cuff performance. The study suggests the benefits of geometric optimization for reconstruction of cuffed anatomoses.

Antenatal Bartter's syndrome: why is this not a lethal condition?

There are four themes in this teaching exercise for Professor McCance. The first challenge was to explain how a premature infant with Bartter's syndrome could survive despite having such a severe degree of renal salt wasting. Second, the medical team wanted to know why there was such a dramatic decrease in the natriuresis in response to therapy, despite the presence of a permanent molecular defect that affected the loop of Henle. Third, Professor McCance was asked why this patient seemed to have a second rare disease, AQP2 deficiency type of nephrogenic diabetes insipidus. The fourth challenge was to develop a diagnostic test to help the parents of this baby titrate the dose of indomethacin to ensure an effective dose while minimizing the likelihood of developing nephrotoxicity. The missing links in this interesting story emerge during a discussion between the medical team and its mentor.

A parametric numerical investigation on haemodynamics in distal coronary anastomoses.

Anastomotic haemodynamics, which plays an important role in the performance of bypass graft, is known to be profoundly affected by the diameter ratio (Phi) and angle (alpha) between the graft and host artery in the peripheral region. We hypothesize that these geometric factors would play similar roles in distal coronary anastomoses and that they could be improved for clinical applications through parametric studies. Anastomotic models covering a range of Phi (1:1, 1.5:1 and 2:1) and alpha (15 degrees , 30 degrees , 45 degrees and 60 degrees ) were investigated numerically in physiological coronary flow conditions. The transient flow patterns, cycle-averaged wall shear stress (WSS), oscillatory shear index (OSI), spatial and temporal WSS gradients (SWSSG and TWSSG) were compared. Results show a stronger influence of Phi than alpha on haemodynamics in distal coronary artery anastomoses. Substantially higher SWSSG and TSSWG occur on the artery floor when Phi=1:1 compared to larger Phi. High levels of OSI occur in critical regions when Phi=1:1 and 2:1. The largest area of high OSI is found in the anastomotic region when alpha=15 degrees , whereas the highest level of SWSSG appears on the artery floor when alpha=60 degrees . The study suggests the clinical relevance of optimizing geometric parameters of coronary anastomoses to improve their haemodynamic performance. We speculate that for a distal coronary anastomosis with a 20:80 proximal-distal flow division ratio maintained in the host artery, Phi=1.5 and alpha=30-45 degrees would enhance its long-term performance.

Parasitic infections among Orang Asli (aborigine) in the Cameron Highlands, Malaysia.

In April 2004, an outbreak of acute diarrheal illness occurred among the Orang Asli (aborigine) in the Cameron Highlands, Pahang State, Peninsular Malaysia, where rotavirus was later implicated as the cause. In the course of the epidemic investigation, stool samples were collected and examined for infectious agents including parasites. Soil transmitted helminthes (STH), namely Ascaris lumbricoides (25.7%), Trichuris trichiura (31.1%) and hookworm (8.1%), and intestinal protozoa, which included Giardia lamblia (17.6%), Entamoeba histolytica/E. dispar (9.4%), Blastocystis hominis (8.1%) and Cryptosporidium parvum (2.7%), were detected. Forty-four (59.5%) were infected with at least one parasite, 24 (32.4%), 12 (16.2%) and 8 (10.8%) had single, double and triple parasitic infections, respectively. STH were prevalent with infections occurring as early as in infancy. Giardia lamblia, though the most commonly found parasite in samples from symptomatic subjects, was within the normally reported rate of giardiasis among the various communities in Malaysia, and was an unlikely cause of the outbreak. However, heavy pre-existing parasitic infections could have contributed to the severity of the rotavirus diarrheal outbreak.

Three-dimensional finite element model of the two-layered oesophagus, including the effects of residual strains and buckling of mucosa.

This study was carried out to develop a two-layered finite element model of the oesophagus. The outer muscle and inner mucosal layer were constructed individually with different mechanical properties and zero-stress opening angles. With the model, two simulations were performed. First, the distention of oesophageal wall under the pressurized state was investigated, from which the effects of residual strains on the stress distribution were evaluated. Second, the buckling modes were determined using a linear eigenvalue analysis. The self-contact capability in ABAQUS was applied to simulate the folding of mucosa under the muscle contraction. The first simulation indicated that, by taking the residual strains into account, the mucosa undertook a very small portion of stress and the luminal pressure almost transmitted completely to the outer muscle layer. On the other hand, the folding of mucosa was shown to be able to reduce the contractile force of circular muscle to maintain the lumen closure. In conclusion, the preliminary study demonstrated the feasibility of simulating the oesophageal peristaltic transport using finite element analysis.

Angiotensin-converting enzyme gene polymorphism and stroke in type 2 diabetic patients in Taiwan.

BACKGROUND: The effect of traditional risk factors on the association between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and stroke was rarely studied previously. We investigated such effect in Taiwanese type 2 diabetic patients. MATERIALS AND METHODS: A total of 872 (422 men and 450 women) patients aged 63.5 (SD: 11.6) years were recruited. Among them, 92 cases (48 men and 44 women) had stroke. Polymerase chain reaction was used to classify the genotypes as II, ID and DD. Analyses were performed in separate sexes. RESULTS: The adjusted odds ratios for stroke for ID vs. II and DD vs. II were 0.837 (0.413-1.697) and 1.778 (0.596-5.300), respectively, for men; but were 1.700 (0.824-3.505) and 3.706 (1.375-9.985), respectively, for women. In models assuming recessive (DD vs. II + ID), dominant (DD + ID vs. II) and additive (II = 0, ID = 1 and DD = 2) transmission, none of the odds ratios was significant for men; but were all significant for women: 2.784 (1.137-6.818), 1.996 (1.006-3.962) and 1.877 (1.155-3.050), respectively. In models using patients without risk factors (hypertension, obesity, smoking or dyslipidaemia ) as a referent group and comparing them to patients with the risk factor and with ID/II, and with DD genotypes, all models (except for smoking) favoured an increasing trend of risk with patients having the risk factor and DD genotype at the highest risk in women. Similar trends for hypertension and dyslipidaemia were also observed in men. CONCLUSION: Traditional risk factors play an important role in the association between the ACE genotypes and stroke. Patients with DD genotype and having traditional risk factors are at the highest risk.

PIV-validated numerical modeling of pulsatile flows in distal coronary end-to-side anastomoses.

This study employed particle image velocimetry (PIV) to validate a numerical model in a complementary approach to quantify hemodynamic factors in distal coronary anastomoses and to gain more insights on their relationship with anastomotic geometry. Instantaneous flow fields and wall shear stresses (WSS) were obtained from PIV measurement in a modified life-size silastic anastomosis model adapted from a conventional geometry by incorporating a smooth graft-artery transition. The results were compared with those predicted by a concurrent numerical model. The numerical method was then used to calculate cycle-averaged WSS (WSS(cyc)) and spatial wall shear stress gradient (SWSSG), two critical hemodynamic factors in the pathogenesis of intimal thickening (IT), to compare the conventional and modified geometries. Excellent qualitative agreement and satisfactory quantitative agreement with averaged normalized error in WSS between 0.8% and 8.9% were achieved between the PIV experiment and numerical model. Compared to the conventional geometry, the modified geometry produces a more uniform WSS(cyc) distribution eliminating both high and low WSS(cyc) around the toe, critical in avoiding IT. Peak SWSSG on the artery floor of the modified model is less than one-half that in the conventional case, and high SWSSG at the toe is eliminated. The validated numerical model is useful for modeling unsteady coronary anastomotic flows and elucidating the significance of geometry regulated hemodynamics. The results suggest the clinical relevance of constructing smooth graft-artery transition in distal coronary anastomoses to improve their hemodynamic performance.

Instability of the two-layered thick-walled esophageal model under the external pressure and circular outer boundary condition.

The mucosal folding is a phenomenon observed for some biological tissues, including the pulmonary airway and gastrointestinal tract. In order to understand the mechanism of the formation of mucosal folding, a thick-walled two-layered cylindrical mathematical model was developed to investigate the buckling behavior under the external pressure and circular outer boundary condition. With the finite element method, the validity and accuracy of the proposed model was verified. The results showed that the fold number was in the range of 4-6, which was agreed with the experimental observation for the mucosal folding of a porcine esophagus. The fold number was found to decrease with the increase in the ratio of the inner to outer material stiffness. The increase in the thickness of inner layer also caused a slight declination of the fold number. Since the effects of both the material and geometrical nonlinearities have been accounted for, this model is more general to be used for the prediction of the buckling behavior of the layered structure with a wide range of thickness ratios and/or stiffness ratios.

3D Mechanical properties of the layered esophagus: experiment and constitutive model.

The identification of a three dimensional constitutive model is useful for describing the complex mechanical behavior of a nonlinear and anisotropic biological tissue such as the esophagus. The inflation tests at the fixed axial extension of 1, 1.125, and 1.25 were conducted on the muscle and mucosa layer of a porcine esophagus separately and the pressure-radius-axial force was recorded. The experimental data were fitted with the constitutive model to obtain the structure-related parameters, including the collagen amount and fiber orientation. Results showed that a bilinear strain energy function (SEF) with four parameters could fit the inflation data at an individual extension very well while a six-parameter model had to be used to capture the inflation behaviors at all three extensions simultaneously. It was found that the collagen distribution was axial preferred in both layers and the mucosa contained more collagen, which were in agreement with the findings through a pair of uniaxial tensile test in our previous study. The model was expected to be used for the prediction of stress distribution within the esophageal wall under the physiological state and provide some useful information in the clinical studies of the esophageal diseases.

Viscoelasticity of esophageal tissue and application of a QLV model.

The time-dependent mechanical properties of the porcine esophagus were investigated experimentally and theoretically. It was hypothesized that the viscoelasticity was quasilinear, i.e., the time and strain effects were independent. In order to verify the separability of time and strain effects, the stress-relaxation test was conducted at various strains and the data were fitted with the Fung's quasilinear viscoelastic (QLV) model. By using the material parameters obtained from the stress relaxation test, the cyclic peak stress and hysteresis were predicted. Results showed that the stress relaxed by 20-30% of the peak stress within the first 10 s and stabilized at approximately 50% at the time of 300 s. The relative stress relaxation R(2) (i.e., the difference of stress at a particular time to the final equilibrium stress normalized by the total difference of the peak and final stress) was not different significantly for various strains. It was also found that, by using the stress-time data during both the ramp and relaxation phases, the correlation between parameters was substantially reduced. The model could also predict the cyclic peak stress and hysteresis except for the underestimate of valley stress. We conclude that the QLV model could be used as the material characterization of the esophageal tissue.

Design and development of the pressure ulcer nursing information system for clinical risk management.

Since 2002, hospitals have to report to Nursing Service Department, Hospital Authority Head Office on the pressure ulcer trends for risk management in Hong Kong. In line with the strategy, hospitals have designed their own patient observation records and reporting forms for monthly analysis and reporting of in-patient hospital acquired pressure ulcers. The incidence rates of individual hospital and its specialties are then calculated manually or using electronic spread sheets. However, the diversity in data definition and vocabulary use generates difficulties in communication among professionals and hospital managers. The development of the system would help to standardize the requirements and to reduce the time required for generating trends and ulcer information. The system also lays the foundation for future systems integration with the changing information system infrastructure.

Finding hepatic portal venous gas in an adult patient: its significance.

Portal venous gas is a well-established radiological finding in neonates. With the advancement in diagnostic imaging, more cases are being reported in adults. We present a 55-year-old man with radiological findings of both portal venous gas and pneumatosis intestinalis secondary to ischaemic necrotising enterocolitis, with subsequent fatality. The significance of finding portal venous gas and its possible aetiology is discussed.

Increasing incidence of diagnosed type 2 diabetes in Taiwan: analysis of data from a national cohort.

AIMS/HYPOTHESIS: Epidemiological evidence shows an increasing prevalence of type 2 diabetes in Taiwan. The aim of this study was to assess the yearly incidence for this country during 1992-1996. SUBJECTS AND METHODS: Data obtained by telephone interviews of 93,484 diagnosed diabetic patients enrolled in Taiwan's National Health Insurance programme formed the basis of this study. A total of 36,153 incident cases of type 2 diabetes (17,097 men and 19,056 women) were identified and incidence rates calculated. The trends of obesity and parental diabetes were also evaluated. RESULTS: The overall 5-year incidences for men and women were 187.1 and 218.4 per 100,000 population, respectively. The trends from 1992-1996 were increased for all age groups in men and for most age groups in women. A 2.8-fold increase in incidence was observed for the youngest age group (<35 years), in which the increase in incidence was higher than in the older age groups. Men showed a higher fold increase in incidence than did women (3.5 vs 2.1). Obesity at interview increased from 39.2% in 1992 to 47.6% in 1996 (p<0.001) and was significant for all ages. Parental diabetes showed no yearly change when all patients were analysed together, but there was a trend towards a decrease in the youngest age group (<35 years) and a trend towards an increase in the oldest age groups (>/=55 years). CONCLUSIONS/INTERPRETATION: An increasing incidence of diagnosed type 2 diabetes was observed for each sex in most age groups in Taiwan, but was most marked in the youngest age group. A parallel increase in obesity was observed with the increasing incidence of diabetes.

Directional, regional, and layer variations of mechanical properties of esophageal tissue and its interpretation using a structure-based constitutive model.

The esophagus, like other soft tissues, exhibits nonlinear and anisotropic mechanical properties. As a composite structure, the properties of the outer muscle and inner mucosal layer are different. It is expected that the complex mechanical properties will induce nonhomogeneous stress distributions in the wall and nonuniform tissue remodeling. Both are important factors which influence the function of mechanosensitive receptor located in various layers of the wall. Hence, the characterization of the mechanical properties is essential to understand the neuromuscular motion of the esophagus. In this study, the uniaxial tensile tests were conducted along two mutually orthogonal directions of porcine esophageal tissue to identify the directional (circumferential and axial), regional (abdominal, thoracic, and cervical), and layer (muscle and mucosa) variations of the mechanical properties. A structure-based constitutive model, which took the architectures of the tissue's microstructures into account, was applied to describe the mechanical behavior of the esophagus. Results showed that the constitutive model successfully described the mechanical behavior and provided robust estimates of the material parameters. In conclusion, the model was demonstrated to be a good descriptor of the mechanical properties of the esophagus and it was able to facilitate the directional, layer, and regional comparisons of the mechanical properties in terms of the associated material parameters.