Degenerative mitral valve prolapse without proper monitoring can cause severe mitral valve failure and occasionally lead to sudden death if the surgical correction is not performed ontime. In most cases, mitral valve prolapse would cause mitral regurgitation which in a severe case would lead to left ventricle failure due to hemodynamic burden. The aim of this study is to develop a model to predict the degeneration behaviour of mitral valve which will aid the medical practitioner to estimate the mitral valve condition based on the available mitral regurgitation data by echocardiogram assessment. Minimal hemodynamic model has been adopted with modification to obtain mitral regurgitation severity information. The stress-strain behaviour of mitral leaflet has also been studied to model the degeneration of the mitral valve leaflet. Both models were validated with the previously published data generated using Windkessel and Burkhoff methods. The coupling of both models gave the degenerative behaviour of mitral valve leaflet in relation with mitral regurgitation severity. The mitral valve degeneration was assessed by mitral valve leaflet elasticity properties while the severity of mitral regurgitation was measured by the volume of mitral regurgitation into the left atrium. It was found that the reduction of mitral valve leaflet elasticity would cause an increase of the mitral regurgitation volume into the left atrium. Mitral regurgitation severity was found to be less than 10% of left ventricle stroke volume when the mitral valve leaflet degenerates more than 90%. At this point, even with a slight increase of less than 10% in the degeneration of mitral valve leaflet, the regurgitation volume might increase suddenly from 5% up to 95% of the left ventricle stroke volume
Congenital absence of the pericardium is a rare condition,which is frequently missed due its subtle presentation. It may be misdiagnosed as another condition causing right heart dilatation such as an intracardiac shunt. We report the finding of diastolic pressure alternans during cardiac catheterization in this single case report of a patient with congenital total absence of the pericardium. The occurrence of this phenomenon is hypothesized to be due to excessive cardiac hypermobility and paradoxical septal movement. We propose that this finding may be a useful clue to the diagnosis.
This is a retrospective study of the prevalence of Human Immunodeficiency Virus (HIV) positive mothers in two states in Malaysia i.e., Perak and Negeri Sembilan since the introduction of the HIV screening programme in antenatal mothers. The study period was from 1/9/97 to 1/9/99. A total of 29 HIV positive antenatal mothers were detected (21 from Perak and 8 from Negeri Sembilan) throughout the study period. Out of the 21 HIV positive mothers from Perak, 8 (38%) were foreign nationals whereas only 1 (12%) out of the 8 from Negeri Sembilan was a foreign national. The main risk factor identified in both the groups was multiple sexual partners. The vertical transmission rates for the patients from Perak were 14.2% and 37.5% in Negeri Sembilan. There was no significant short-term adverse obstetric outcome.
Hydatidiform mole with a coexistent fetus is a rare occurrence with an incidence of I per 22,000-100,000 pregnancies. It is associated with persistent gestational trophoblastic tumour. Hence an early and correct diagnosis is imperative to plan subsequent management of such patients. We report a case of a primigravida who presented with vaginal bleeding at early second trimester. Expectant management was carried out for her pregnancy which finally ended in an abortion. The pathology, clinical findings and current management of this rare entity is discussed.
Massive postpartum haemorrhage after Cesarean section for placenta previa is a common occurrence. The bleeding is usually from the placental bed at the lower uterine segment. Uterine tamponade has a role in the management of such patients especially when fertility is desired. We describe here a case of massive postpartum haemorrhage, which was managed, with the use of a Sengstaken-Blakemore tube. This allowed us to avoid a hysterectomy for a young primiparous patient.
Aluminium (Al) accumulation is a common trait expressed in at least 60 plant families and particularly prevalent in tropical woody plants. However, the functional significance and genetic or physiological controls on Al accumulation are currently unknown. We tested the hypothesis that differential expression of Al accumulation among wild populations of the Al-accumulating tropical shrub Melastoma malabathricum L. is associated with habitat-related variation in total and exchangeable soil Al concentrations. Mature leaves and seeds were sampled from 20 populations of M. malabathricum growing in six habitats across Peninsular Malaysia, and soil was collected from each site. The seeds were grown in hydroponic solutions comprising 50% Hoagland's solution amended with Al in the form of 1.0 mM AlCl3 to test the hypothesis that differential expression of foliar Al accumulation is an inherited trait. Foliar Al concentrations varied significantly among populations, but were not consistently different among plants growing in different habitats and showed no relationship to total or exchangeable Al concentrations in soils collected at the 20 sites. Mean foliar Al concentration in wild plants was positively correlated with foliar calcium (Ca) concentrations, and with total soil nitrogen (N), Ca and magnesium (Mg) concentrations, across the 20 populations, and Al addition increased foliar concentrations of phosphorus, Ca, Mg and potassium in seedlings. The differential expression of Al accumulation in M. malabathricum populations is uncoupled to local variation in soil Al concentrations, but may be sensitive to local soil-related variation in the availability of other macro-nutrients, in particular N, Ca and Mg. Further research on the factors controlling Al uptake should focus on the plasticity of this trait within populations of Al accumulators and interactions with micro-habitat variation in the availability of the macronutrient cations.
Aluminium (Al) hyper-accumulation is a common trait expressed by tropical woody plants growing on acidic soils. Studies on Al accumulators have suggested that Al addition may enhance plant growth rates, but the functional significance of this trait and the mechanistic basis of the growth response are uncertain. This study aimed to test the hypothesis that differential growth responses to Al among populations of an Al accumulator species are associated with variation in biomass allocation and nutrient uptake. We conducted two experiments to test differential responses to the presence of Al in the growth medium for seedlings of the Al accumulator shrub Melastoma malabathricum collected from 18 populations across Peninsular Malaysia. Total dry mass and relative growth rate of dry mass were significantly greater for seedlings that had received Al in the growth medium than for control plants that did not receive Al, but growth declined in response to 5.0 mM Al addition. The increase in growth rate in response to Al addition was greater for a fast-growing than a slow-growing population. The increase in growth rate in response to Al addition occurred despite a reduction in dry mass allocation to leaves, at the expense of higher allocation to roots and stems, for plants grown with Al. Foliar concentrations of P, K, Mg and Ca increased in response to Al addition and the first axis of a PCA summarizing foliar nutrient concentrations among populations was correlated positively with seedling relative growth rates. Some populations of the Al hyper-accumulator M. malabathricum express a physiological response to Al addition which leads to a stimulation of growth up to an optimum value of Al in the growth medium, beyond which growth declines. This was associated with enhanced nutrient concentrations in leaves, which suggests that Al accumulation functions to optimize elemental stoichiometry and growth rate.
Climatic records for Danum for 1985-1998, elsewhere in Sabah since 1879, and long monthly rainfall series from other rainforest locations are used to place the climate, and particularly the dry period climatology, of Danum into a world rainforest context. The magnitude frequency and seasonality of dry periods are shown to vary greatly within the world's rainforest zone. The climate of Danum, which is aseasonal but subject, as in 1997-1998, to occasional drought, is intermediate between less drought-prone north-western Borneo and the more drought-prone east coast. Changes through time in drought magnitude frequency in Sabah and rainforest locations elsewhere in South-East Asia and in the Neotropics are compared. The 1997-1998 ENSO-related drought event in Sabah is placed into a historical context. The effects of drought on tree growth and mortality in the tropics are assessed and a model relating intensity and frequency of drought disturbance to forest structure and composition is discussed.
The aim of this article is to provide a perspective on the relative importance and contribution of different imaging modalities in patients with valvular heart disease. Valvular heart disease is increasing in prevalence across Europe, at a time when the clinical ability of physicians to diagnose and assess severity is declining. Increasing reliance is placed on echocardiography, which is the mainstay of cardiac imaging in valvular heart disease. This article outlines the techniques used in this context and their limitations, identifying areas in which dynamic imaging with cardiovascular magnetic resonance and multislice CT are expanding.
A retrospective study was carried out on 42 patients (38 males, 4 females, mean age 25.9) with liver injury at the University Hospital, Kuala Lumpur from 1994 through to 1991. Prognostic factors that might help to identify those patient survival was related to pulse rate on arrival ( < or = 120 beats per minute, p = 0.027), systolic blood pressure at induction of anaesthesia ( > or = to 80 mmHg, p = 0.003) and intraoperative blood transfusion of < or = to 4 units (p = 0.05). This data were supported by the 95% confidence interval suggesting that these factors may be strong prognostic indicators individually. Increased mortality was also associated with increased total blood transfused (p = 0.002) and grade of liver injury (p = 0.02). Although the factors we have identified reflect both the severity of injury and resuscitative and surgical efforts, further studies using a prospective design are required to confirm these findings.