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Biomedical subjects

E George

Publications and source records attributed to E George.

At least 19 recordsLinked to original sources
PubMed2006

Screening of concurrent alpha-thalassaemia 1 in beta-thalassaemia carriers.

Thalassaemia is an inherited blood disorder and is a significant public health problem in Malaysia, with many not knowing they carry the gene for thalassaemia. The two major forms are alpha and beta thalassaemia. An individual can co-inherit both the alpha and beta thalassaemia genes. This study determined the frequency of concurrent carriers of alpha thalassaemia in 231 beta thalassaemia carriers. Gap-PCR was done on extracted DNA of the beta thalassaemia samples to check for alpha thalassaemia 1 molecular defect. Eight (3.5%) samples were found to have concurrently inherited the alpha thalassaemia 1 (- -SEA) deletion. The significant carrier rate for alpha thalassaemia 1 indicates the need for the implementation of DNA analysis to complement thalassaemia screening in high risk populations.

Chromatography, High Pressure Liquid↗
PubMed2005

[Treatment of intestinal failure by total parenteral nutrition at home in children and adults].

Intestinal failure is characterised by inability of the intestine to absorb sufficient nutrients to maintain the integrity and function of the body. This can be caused by malabsorption due to too short an intestine or an abnormality of the mucosa, or by a severe motility disorder. In addition to dietary measures, the prescription of total parental nutrition (TPN) at home is sometimes necessary. This treatment is a burden on the patient and the risk of complications must be reduced to a minimum. The risks of long-term parenteral nutrition can be limited and the quality of the provision of services can be increased if the co-ordination is in the hands of a centre for home parenteral nutrition. In the Netherlands there are two centres for home-TPN: the St Radboud University Medical Centre in Nijmegen and the University Medical Centre (AMC) in Amsterdam. In both children and adults, the most common indications are the short bowel syndrome and motility disorders. However, the syndromes that cause this are clearly different in the different age groups. Parenteral nutrition can be given for long periods of time. A large variety of complications can occur, related especially to the equipment or the nutrients. When the nutrition is given via a central venous catheter, then sepsis is a serious and possibly life-threatening complication. In case of administration via an arteriovenous shunt, thrombosis of the shunt is the most frequent problem. If the treatment by means of home-TPN fails, then transplantation of the small intestine should be considered.

Adult↗
PubMed2005

Excess non-spine fractures in women over 50 years with celiac disease: a cross-sectional, questionnaire-based study.

The association of celiac disease with fracture is controversial. Recent studies may have underestimated the impact by studying patients with low fracture risk. Since postmenopausal women are at greatest risk of fracture, we have investigated non-spine fracture occurrence in women > or =50 years with celiac disease. Patients were recruited from hospital and general practice as well as from volunteers, controls from general practice. All completed a questionnaire detailing fracture occurrence. Three hundred and eighty-three female celiac patients and 445 female controls aged > or =50 years at time of study were compared. Mean age was 61.4+/-7.8 years in celiac patients and 62.7+/-9.9 years in controls. Celiac patients were lighter but not shorter. Celiac patients displayed greater "all fracture" prevalence (odds ratio [OR], 1.51; confidence interval [CI], 1.13:2.02) and fracture after 50 years (OR, 2.20; CI, 1.49:3.25). Wrist fracture was more frequent (OR, 1.65; CI, 1.12:2.41), but significance was lost once height and weight were taken into account. Celiac patients had more multiple fractures (OR, 2.96; CI, 1.81:4.83). To investigate the association of fracture with time from diagnosis, 324 celiac patients were paired with a control by age. No excess fracture risk was found more than 10 years before diagnosis amongst celiac patients diagnosed after age 50 years, but risk increased in the period from 10 years before diagnosis to 5 years after and remained high more than 5 years after diagnosis ( p<0.05). Wrist fracture only increased in the period more than 5 years after diagnosis ( p<0.05). In women diagnosed before 50 years, no excess fracture risk existed. Fracture risk in female celiac patients >50 years is increased overall but is related largely to the peri-diagnostic period. Wrist fracture risk is partly accounted for by height and weight, but is more common more than 5 years after diagnosis. Celiac testing may be indicated in thin women over 50 years with multiple fractures, and after diagnosis adequate calcium and vitamin D intake should be ensured.

Age Factors↗
PubMed2005

K+ currents regulate the resting membrane potential, proliferation, and contractile responses in ventricular fibroblasts and myofibroblasts.

Despite the important roles played by ventricular fibroblasts and myofibroblasts in the formation and maintenance of the extracellular matrix, neither the ionic basis for membrane potential nor the effect of modulating membrane potential on function has been analyzed in detail. In this study, whole cell patch-clamp experiments were done using ventricular fibroblasts and myofibroblasts. Time- and voltage-dependent outward K(+) currents were recorded at depolarized potentials, and an inwardly rectifying K(+) (Kir) current was recorded near the resting membrane potential (RMP) and at more hyperpolarized potentials. The apparent reversal potential of Kir currents shifted to more positive potentials as the external K(+) concentration ([K(+)](o)) was raised, and this Kir current was blocked by 100-300 muM Ba(2+). RT-PCR measurements showed that mRNA for Kir2.1 was expressed. Accordingly, we conclude that Kir current is a primary determinant of RMP in both fibroblasts and myofibroblasts. Changes in [K(+)](o) influenced fibroblast membrane potential as well as proliferation and contractile functions. Recordings made with a voltage-sensitive dye, DiBAC(3)(4), showed that 1.5 mM [K(+)](o) resulted in a hyperpolarization, whereas 20 mM [K(+)](o) produced a depolarization. Low [K(+)](o) (1.5 mM) enhanced myofibroblast number relative to control (5.4 mM [K(+)](o)). In contrast, 20 mM [K(+)](o) resulted in a significant reduction in myofibroblast number. In separate assays, 20 mM [K(+)](o) significantly enhanced contraction of collagen I gels seeded with myofibroblasts compared with control mechanical activity in 5.4 mM [K(+)](o). In combination, these results show that ventricular fibroblasts and myofibroblasts express a variety of K(+) channel alpha-subunits and demonstrate that Kir current can modulate RMP and alter essential physiological functions.

Animals↗
PubMed2004

Molecular defects in the beta-globin gene identified in different ethnic groups/populations during prenatal diagnosis for beta-thalassemia: a Malaysian experience.

Beta-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 beta-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71-72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb Ggamma(Agammadeltabeta) degrees and 45-kb Filipino deletions. The 192 beta-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 beta-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of beta-thalassemia. beta-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese beta-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay beta-thalassemia carrier. The beta-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of beta-thalassemia in Malaysia.

Asian People↗
PubMed2003

Immediate dual energy X-ray absorptiometry reveals a high incidence of osteoporosis in patients with advanced prostate cancer before hormonal manipulation.

OBJECTIVE: To examine the incidence of osteoporosis in patients with advanced prostate cancer (using forearm densitometry) before commencing androgen deprivation therapy (ADT), as osteoporotic fractures are more frequent in patients with prostate cancer who have undergone either medical or surgical castration, because of rapid loss of bone mass. PATIENTS AND METHODS: In all, 174 patients (mean age 74.6 years, range 46-90) with advanced prostate cancer presented over 2 years. Their forearm bone densitometry values were compared with those from 106 age-matched controls (mean age 74.3 years, range 66-90). RESULTS: Of the 174 patients, 73 (42%) were osteoporotic (t score <or=- 2.5) and 65 (37%) were osteopenic (t score - 1 to - 2.4). This compares with a 27% incidence of osteoporosis in the control group (P = 0.022). There were also no significant correlations between prostate specific antigen levels, Gleason score, tumour stage, biochemical markers and the presence or absence of osteoporosis risk factors. CONCLUSION: Patients with advanced prostate cancer requiring ADT have a high incidence of osteoporosis before treatment. In addition, osteoporosis in these men cannot be predicted from clinical or biochemical values. Therefore, bone densitometry should be used in all patients with advanced cancer requiring ADT, as the results have implications for the choice of cancer therapy and the prophylaxis for osteoporosis.

Absorptiometry, Photon↗
PubMed2002

A comparison of experimental, theoretical, and numerical simulation Rayleigh-Taylor mixing rates.

We present a Rayleigh-Taylor mixing rate simulation with an acceleration rate falling within the range of experiments. The simulation uses front tracking to prevent interfacial mass diffusion. We present evidence to support the assertion that the lower acceleration rate found in untracked simulations is caused, at least to a large extent, by a reduced buoyancy force due to numerical interfacial mass diffusion. Quantitative evidence includes results from a time-dependent Atwood number analysis of the diffusive simulation, which yields a renormalized mixing rate coefficient for the diffusive simulation in agreement with experiment.

Journal Article↗
PubMed2002

V-Y advancement flap and composite graft for alar-groove reconstruction.

A one-stage procedure combining a V-Y advancement flap with a composite graft for the reconstruction of alar-lobule and alar-groove defects is described. After tumour resection, a V-Y flap is advanced and retained at the level of the piriform margin to fill the dead space. To provide vascular support to the composite graft and to recreate the alar groove the advancing edge of the flap is de-epithelialised. In the same stage the composite graft is harvested and placed into the alar defect. A series of 12 patients underwent this procedure, with good results.

Aged↗
PubMed2002

Hemodynamic monitoring.

The goal of hemodynamic monitoring is to maintain adequate tissue perfusion. Classical hemodynamic monitoring is based on the invasive measurement of systemic, pulmonary arterial and venous pressures, and of cardiac output. Since organ blood flow cannot be directly measured in clinical practice, arterial blood pressure is used, despite limitations, as estimate of adequacy of tissue perfusion. A mean arterial pressure (MAP) of 70 mm Hg may be considered a reasonable target, associated with sign of adequate organ perfusion, in most patients. In the approach to hypotension, which is the most common cause of hemodynamic instability in critical ill patients, increasing levels of monitoring may be used. Assuming that central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) are adequate estimates of the volume of the systemic and pulmonary circulation respectively, the following decision tree is suggested: 1) make a working diagnosis based on the relationship between pressure (CVP and PAOP) and cardiac output or stroke volume (CO or SV); 2) consider conditions that may alter reliability of CVP and PAOP in estimate adequately circulating volumes such as abnormal pressure/volume relationship (compliance) of the RV or LV, increased intrathoracic pressure (PEEP, autoPEEP, intra-abdominal pressure), valvular heart disease (mitral stenosis); 3) look at the history; 4) separating RV and LV by reciprocal variations of CVP, PAOP and SV. CVP is often used as sole parameter to monitor hemodynamic. However CVP alone may not differentiate between changes in volume (different venous return curve) or changes in contractility (different starling curve). Finally, other techniques such as echocardiography, transesophageal Doppler and volume-based monitoring system are now available.

Blood Pressure↗
PubMed2001

Gene mutations in the succinate dehydrogenase subunit SDHB cause susceptibility to familial pheochromocytoma and to familial paraganglioma.

The pheochromocytomas are an important cause of secondary hypertension. Although pheochromocytoma susceptibility may be associated with germline mutations in the tumor-suppressor genes VHL and NF1 and in the proto-oncogene RET, the genetic basis for most cases of nonsyndromic familial pheochromocytoma is unknown. Recently, pheochromocytoma susceptibility has been associated with germline SDHD mutations. Germline SDHD mutations were originally described in hereditary paraganglioma, a dominantly inherited disorder characterized by vascular tumors in the head and the neck, most frequently at the carotid bifurcation. The gene products of two components of succinate dehydrogenase, SDHC and SDHD, anchor the gene products of two other components, SDHA and SDHB, which form the catalytic core, to the inner-mitochondrial membrane. Although mutations in SDHC and in SDHD may cause hereditary paraganglioma, germline SDHA mutations are associated with juvenile encephalopathy, and the phenotypic consequences of SDHB mutations have not been defined. To investigate the genetic causes of pheochromocytoma, we analyzed SDHB and SDHC, in familial and in sporadic cases. Inactivating SDHB mutations were detected in two of the five kindreds with familial pheochromocytoma, two of the three kindreds with pheochromocytoma and paraganglioma susceptibility, and 1 of the 24 cases of sporadic pheochromocytoma. These findings extend the link between mitochondrial dysfunction and tumorigenesis and suggest that germline SDHB mutations are an important cause of pheochromocytoma susceptibility.

Amino Acid Sequence↗
PubMed2001

Measles antibody responses after early two dose trials in Guinea-Bissau with Edmonston-Zagreb and Schwarz standard-titre measles vaccine: better antibody increase from booster dose of the Edmonston-Zagreb vaccine.

In Guinea-Bissau, children were randomised at 6 months of age to receive either two doses of standard-titre measles vaccine at 6 and 9 months of age or an inactivated polio vaccine at 6 months and standard-titre measles vaccine at 9 months of age. During the first 5 months, children received Edmonston-Zagreb (EZ) vaccine and during the following 11 months, the Schwarz (SW) vaccine. Five percent of the mothers, 74% of children at 6 months of age, and 92% of unvaccinated children at 9 months of age had unprotective levels (<125 mIU/ml) of measles antibodies. Among children receiving EZ vaccine, 1% were unprotected at 18 months of age after either two (3/240) or one (3/211) doses of vaccine, the geometric mean measles antibody titre (GMT) being approximately 1550 mIU/ml in both groups. Among those receiving SW vaccine 9% (34/365) and 3% (9/310) were unprotected at 18 months of age in the two-dose and the one-dose groups (RR = 3.21 (95% confidence interval (CI) 1.56-6.58)), respectively. The GMT was higher after one dose of SW vaccine at 9 months of age (2491 mIU/ml) than after two doses of SW vaccine (1125 mIU) (P < 0.001). In the EZ vaccine group, there was no significant difference in antibody level for children vaccinated in the presence of high or low levels of maternal antibodies, whereas there was a marked difference in the SW group. The second EZ vaccine induced a significant antibody increase between 9 months of age (1191 mIU) and 18 months of age (1602 mIU, P=0.011), whereas antibody levels tended to decline from 9 months (1243 mIU) to 18 months of age (998 mIU, P = 0.124) after the second dose of SW vaccine. Conclusively, after two doses of EZ measles vaccine more children were protected at 18 months of age than after two doses of SW. One dose of SW provided the highest antibody response, but a higher proportion of unprotected than one or two doses of EZ. The EZ vaccine was less sensitive to maternal antibodies, and able to increase the antibody response by revaccination, while the second SW vaccine resulted in an unchanged or lower antibody response.

Age Factors↗
PubMed2001

Examining the effects of work externalization through the lens of social identity theory.

This study examines whether dissimilarity among employees that is based on their work status (i.e., whether they are temporary or internal workers) influences their organization-based self-esteem, their trust in and attraction toward their peers, and their altruism. A model that is based on social identity theory posits that work-status dissimilarity negatively influences each outcome variable and that the strength of this relationship varies depending on whether employees have temporary or internal status and the composition of their work groups. Results that are based on a survey of 326 employees (189 internal and 137 temporary) from 34 work groups, belonging to 2 organizations, indicate that work-status dissimilarity has a systematic negative effect only on outcomes related to internal workers when they work in temporary-worker-dominated groups.

Adult↗