Geometric and Excited-State Properties of 1,4-Bis(benzothiazolylvinyl)benzene Interacting with 2,2‘,2‘ ‘-(1,3,5-phenylene)tris[1-phenyl-1H-benzimidazole] Studied by a Density-Functional Tight-Binding Method

The energetics and luminescent property of a guest molecule, 1,4-bis(benzothiazolylvinyl)benzene (BT), interacting with a host molecule, 2,2',2' '-(1,3,5-phenylene)tris[1-phenyl-1H-benzimidazole] (TPBI), in organic light-emitting diodes are studied by performing excited-state calculations using a time-dependent density-functional tight-binding method complemented with dispersion energy. It is found that the overlap between the TPBI emission and the BT absorption spectra shows an efficient energy transfer from the host molecule to the guest molecule when they are excited. The planar BT molecule becomes distorted when it is mixed with TPBI, resulting in a blue luminescence around 475 nm. The separation of the TPBI + BT mixture on a graphite surface is found to be energetically favorable, consistent with experimental observation.

7-Ketocholesterol enhances 1-methyl-4-phenylpyridinium-induced mitochondrial dysfunction and cell death in PC12 cells

The present study investigated the promoting effect of oxysterol 7-ketocholesterol against the cytotoxicity of 1-methyl-4-phenylpyridinium (MPP(+)) in differentiated PC12 cells. 7-Ketocholesterol significantly enhanced the MPP(+)-induced nuclear damage, decrease in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species and depletion of GSH. N-Acetylcysteine, ascorbate, trolox, carboxy-PTIO and Mn-TBAP reduced the cytotoxic effect of MPP(+) in the presence of 7-ketocholesterol. The results indicate that 7-ketocholesterol shows a synergistic effect against the cytotoxic effect of MPP(+). 7-Ketocholesterol may enhance the MPP(+)-induced viability loss in PC12 cells by promoting the mitochondrial membrane permeability change, release of cytochrome c and subsequent activation of caspase-3, which is associated with the increased formation of reactive oxygen species and depletion of GSH. The findings suggest that 7-ketocholesterol as a promoting agent for the formation of mitochondrial permeability transition may enhance the toxic neuronal cell injury.

Mitochondria are impaired in the adipocytes of type 2 diabetic mice

AIMS/HYPOTHESIS

The aim of this study was to confirm a link between mitochondrial dysfunction and type 2 diabetes.

MATERIALS AND METHODS

Cellular levels of mitochondrial proteins, cellular mitochondrial DNA content, and mitochondrial function and morphology were assessed by MitoTracker staining and electron microscopy, in white adipose tissue of 12-week-old male wild-type, obese (ob/ob), and diabetic (db/db) mice.

RESULTS

Levels of mitochondrial proteins were found to be very similar in the livers and muscles of all the mice studied. However, levels were greatly decreased in the adipocytes of db/db mice, but not in those of the wild-type and ob/ob mice. Levels of mitochondrial DNA were also found to be considerably reduced in the adipocytes of db/db mice. MitoTracker staining and under electron microscopy revealed that the number of mitochondria was reduced in adipocytes of db/db mice. Respiration and fatty acid oxidation studies indicated mitochondrial dysfunction in adipocytes of db/db mice. Interestingly, there was an increase in mitochondria and mitochondrial protein production in adipocytes of db/db mice treated with rosiglitazone, an agent that enhances insulin sensitivity.

CONCLUSIONS/INTERPRETATION

Taken together, these data indicate that mitochondrial loss in adipose tissue is correlated with the development of type 2 diabetes.

The roles of progestagen and uterine irritant in the maintenance of cystic endometrial hyperplasia in the canine uterus

Cystic endometrial hyperplasia (CEH) was induced in the left uterine horns of 14 mature ovariectomised greyhound bitches with an intra-luminal silk suture (uterine irritant) and treatment with estradiol benzoate and megestrol acetate (to simulate stages of a normal canine estrous cycle). Right uterine horns served as suture-free controls. From Day 30 of simulated diestrus, bitches received treatments of suture removal (n = 4), progestagen withdrawal (n = 5) or both (n = 5). Necropsies were performed 3 or 9 weeks later. At 3 weeks, severe cystic endometrial hyperplasia was present in all (6/6) left horns and in no (0/6) right horns. At 9 weeks, the left horns in 5/6 of bitches subjected to progestagen-withdrawal had recovered (in varying degrees) from cystic endometrial hyperplasia, whereas no recovery was evident in the left horns of bitches (n = 2) that continued to receive progestagen. This study demonstrated that: (i) cystic endometrial hyperplasia was reversible upon withdrawal of progestagen; (ii) progestagen maintained cystic endometrial hyperplasia in the presence or absence of irritant; and (iii) persistent endometrial irritation in the absence of progestagen may not maintain cystic endometrial hyperplasia.

Alteration of foot temperature in diabetic neuropathy: is it another piece of puzzle?

Poor glycaemic control and the duration of diabetes mellitus are known to accelerate development and progression of neuropathy. Diabetic co-morbidities: hypertension and hyperlipidaemia, have been postulated to associate with development of neuropathy. A diabetic foot with low temperature and frequent exposure to low temperature environment has recently been hypothesized to be at higher risk to develop early neuropathy. This cross-sectional study is undertaken to identify risk factors for diabetic neuropathy and the association between foot temperature and development of diabetic neuropathy by using simple clinical examination in the outpatient setting. From April 18, to April 30, 2005, universal sampling method was used to select 134 diabetic patients (type 1 or type 2 for >1 year) with peripheral neuropathy. Excluded are those with chronic alcoholism, drug-induced neuropathy, dietary history of vitamin B deficiency and family history of porphyria and hereditary sensorimotor neuropathy. The patient's duration of diabetes, glycaemic control status and the presence of co-morbids: hypertension and hyperlipidemia, were recorded. The temperature of the foot was measured by using thermo buddy. Of 134 patients representing Malaysian ethnic distribution with an equal number of males and females, 20.1% were in the age group of 61 to 65 years and, 85.1% and 67.9% belonged to lower socioeconomic and educational groups respectively. Associations between diabetic neuropathy and glycaemic control (p = 0.018) and duration of diabetes (p < 0.05) were significant. However, hypertension, hyperlipidaemia and low foot temperature were not significantly associated with development of diabetic neuropathy. Poor glycaemic control is significantly associated with diabetic neuropathy. Foot temperature alteration is merely an effect of autonomic neuropathy with a cold foot is attributed to co-existing peripheral arterial disease.

Necrotizing fasciitis of the lower limb: an outcome study of surgical treatment

Necrotizing fasciitis is a limb- and life-threatening rapidly spreading infection affecting the deep fascia with secondary necrosis of the subcutaneous tissue. It requires immediate medical attention and emergency surgery to prevent morbidity and death. This study was undertaken to determine its co-morbidity and risk factors affecting the outcome of its surgical treatment. This is a retrospective review of 36 cases of necrotizing fasciitis of the lower limb treated in our center between 1998 and 2002. Only 19% of the cases were correctly diagnosed upon admission and 48.6% were initially diagnosed as 'cellulitis'. Diabetes mellitus was the most common co-morbid. Pseudomonas, Staphylococcus, Streptococcus and Enterobactericae were the common pathogens isolated. Ten patients (27.8%) had major amputation as part of radical debridement. The overall mortality rate was 36% with laboratory parameters: high serum urea and creatinine, and low haemoglobin levels were predictors for higher mortality. Poor white cell response which is common in diabetic patients and a delay in surgical debridement were. notable attributes to a higher mortality. Necrotizing fasciitis is a serious infection associated with significant morbidity and mortality. A poor white blood cell response, high serum urea and creatinine, and low haemoglobin level were the predictors for mortality. Early diagnosis and prompt treatment are of paramount importance in the treatment of this infection.

Integrated microfluidic UV absorbance detector with attomol-level sensitivity for BSA

An integrated UV absorbance detection system employing a novel silicon-in-plastic technology to seamlessly integrate bare UV photodiode chips into polymer microfluidic systems has been developed. Detection platforms fabricated using this approach exhibit exceptionally low concentration and mass detection limits down to 15 nM and 9.8 amol, respectively, for bovine serum albumin (BSA) as a model protein. In addition to providing high sensitivity, sub-nanoliter detection volumes are enabled by the use of direct photodiode integration. The fabrication methodology is detailed, and system performance metrics including detection limits, detection volume, dynamic range, and linearity are reported.

Gene expression profiling in breast cancer: towards individualising patient management

Breast cancer is a complex and clinically heterogeneous disease. The increase in knowledge of breast cancer biology has led to a number of clinical advances in the treatment of breast cancer, most notably the implementation of widespread mammography screening and advances in adjuvant treatment of early-stage disease. In the last 20 years, arrays of potential prognostic and/or predictive markers of breast cancer have been analysed. However, relatively few have proven to be clinically useful. To date, the only widely accepted markers for routine use in breast cancer are the oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor, HER-2 (c-erbB2/neu). Expression microarray technology and laser capture microdissection have now been employed to further our understanding of the molecular pathogenesis of breast cancer. Recently reported advances in array technology and RNA amplification methods are having a considerable impact in this field, allowing the analysis of pre-malignant and pre-invasive lesions. A number of studies have identified prognostic and predictive gene 'signatures', whose prediction of disease outcome and response to treatment is superior to conventional prognostic indicators. Despite major technological advances, a number of confounding issues remain concerning the potential clinical utility of gene expression profiling, including differences in study design, patient selection, array technology, chemistry, and methods of analysis. It seems likely, however, that following careful 'hypothesis driven' validation studies and clinical trials, expression profiling will be applied in the future to identify patient-specific disease profiles and provide rationale for individualised treatment. This review focuses on the current use and future potential of microarray profiling in breast cancer.

Activation of the extracellular signal regulated kinase (ERK) pathway in human melanoma

BACKGROUND

Several studies suggest that melanoma may be resistant to treatment because of resistance to apoptosis and that this may be the result of activation of the extracellular signal regulated kinase (ERK1/2) pathway.

AIMS

To test this hypothesis by examining the expression of ERK1/2 and its activated form in histological sections of melanoma and its relation to known prognostic features of the disease.

MATERIALS/METHODS

Immunohistochemistry with antibodies to ERK1/2 and phosphorylated ERK (p-ERK) was performed on formalin fixed sections from 42 primary melanomas, 38 metastases, and 20 naevi. Fourteen of the primary melanomas were in the radial and 28 in the vertical growth phase.

RESULTS

ERK1/2 was widely expressed (100%) in all the (pigmented) lesions studied. p-ERK1/2 expression was much lower in compound (32.4%) and dysplastic (54.5%) naevi than in primary melanoma (nodular 78.8%, superficial spreading 67%) and subcutaneous metastases (76.3%). p-ERK expression was much lower in lymph node metastases (48.5%), suggesting that the microenvironment may influence the activation of ERK. There was a (non-significant) trend for p-ERK expression to be higher in thick (>1.0 mm) versus thin (< or =1.0 mm) melanoma (p = 0.23). There was a trend for overall survival to be related to p-ERK expression in patients with melanoma over 1 mm in thickness.

CONCLUSIONS

Expression of activated ERK1/2 in melanocytic lesions appears to be related to malignant potential so that activation of ERK1/2 may be important in melanoma progression. These results provide important histological support for the proposal that inhibition of this signalling pathway may be useful in treatment of melanoma.

Stromal nitric oxide synthase (NOS) expression correlates with the grade of mammary phyllodes tumour

BACKGROUND

Nitric oxide synthase (NOS), particularly endothelial and inducible forms (e/i-NOS), are expressed in various cancers, including breast cancer. In mammary fibroepithelial lesions, NOS expression in stromal cells has been reported to be lower in fibroadenomas than in phyllodes tumours.

AIMS

To investigate NOS expression in phyllodes tumours of varying degrees of malignancy.

METHODS

One hundred and sixty seven mammary phyllodes tumours (97 benign, 47 borderline malignant, and 23 frankly malignant) were evaluated for e-NOS and i-NOS expression by immunohistochemistry. Correlations with previously reported expression of stromal vascular growth factor (VEGF) and microvessel density were also performed.

RESULTS

Stromal expression of e-NOS was absent, weak, moderate, and strong in 43%, 31%, 13%, and 13% of benign tumours; 17%, 26%, 13%, and 44% of borderline malignant tumours; and 17%, 35%, 13%, and 35% of frankly malignant tumours, respectively. Stromal expression of i-NOS was 77%, 18%, 4%, and 1% in benign tumours; 42%, 28%, 19%, and 11% in borderline malignant tumours; and 43%, 13%, 26%, and 18% in frankly malignant tumours, respectively. Stromal expression of both i-NOS and e-NOS was significantly different between the benign and malignant (borderline and frank) groups of phyllodes tumours (p < 0.0001). Furthermore, the expression of i-NOS correlated with stromal VEGF expression and microvessel density. The expression of NOS in the epithelial cells was strong, and showed no differences between the different groups of tumours.

CONCLUSIONS

Higher stromal expression of NOS in phyllodes tumours is associated with malignancy, suggesting a possible role in malignant progression, particularly metastasising potential.

Molecular cloning and characterization of full-length cDNAs encoding a novel high-molecular-weight Dermatophagoides pteronyssinus mite allergen, Der p 11

BACKGROUND

Dermatophagoides pteronyssinus (Dp) and D. farinae (Df) mites are the most important source of indoor aeroallergens. Most Dp mite allergens identified to date have relatively low molecular weights (MWs). Identification of high-MW mite allergens is a crucial step in characterizing the complete spectrum of mite allergens and to provide appropriate tools for diagnostic and therapeutic application.

METHODS

The full-length Der p 11 cDNA clone was isolated using cDNA library immunoscreening, the 5'-3' rapid amplification of cDNA ends (RACE) system and polymerase chain reactions (PCR). The whole cDNA insert and its PCR-derived DNA fragments (p1 to p4) were generated and expressed in the Escherichia coli expression system. The allergenicity of the recombinant protein and its peptide fragments was examined by IgE immunodot assays. The IgE-binding reactivity of rDer p 11 was analyzed in the serum of 50 asthmatic children with positive reactivity to Dp mite extract. Its recombinant peptide fragments were also examined by immunodot assays in 30 mite-allergic children.

RESULTS

Der p 11 cDNA consists of a 2625-bp open reading frame encoding a 103-kDa protein with 875 amino acids. It exhibits significant homology with the paramyosin of other invertebrates. The protein sequence alignment of this newly identified Dp mite allergen (denominated as Der p 11) revealed over 89% identity with Der f 11 and Blo t 1. Among 50 Dp-sensitive asthmatic children, rDer p 11 showed positive IgE-binding reactivity to 39 patients (78%). Using immunodot assays, multiple human IgE-binding activities were demonstrated in all four fragments of Der p 11. Using immunoblot assays, the dominant IgG-binding epitope for monoclonal antibody (mAb642) was located in fragment p3 only. In immunoblot assays, cross-inhibition between rDer p 11 and rDer f 11 was up to 73-80% at concentrations of 100 microg/ml.

CONCLUSIONS

This study confirms that the newly identified recombinant Der p 11 is a novel and important high-MW Dp mite allergen for asthmatic children. Our data also indicates that human IgE-binding major epitopes are scattered over the entire molecule of Der p 11.

Calcium/Poly(9,9-dioctylfluorene) Interaction: A Theoretical Study

The geometric and electronic structures of poly(9,9-dioctylfluorene) (PFO) oligomer interacting with Ca atoms were studied using Møller-Plesset perturbation theory. A weak interaction with little charge transfer and with a relatively long Ca-C distance (about 4.0 Angstrom) was found when only one Ca atom was attached to a PFO unit. However, when two Ca atoms were adsorbed at a PFO unit, a strong interaction with a shorter Ca-C distance (about 2.67 Angstrom) took place with considerable charge transfer from the Ca atom to the PFO, resulting in significant deformation in the backbone of the PFO oligomer. In the latter case, the frontier orbitals of the PFO were modified. However, the deformed PFO and its modified frontier orbitals could be recovered when oxygen was added, which is in good agreement with experimental observation.

Wavelength-Controlled Lasing in Znx Cd1- x S Single-Crystal Nanoribbons

Zn_x Cd_{1 - x} S single-crystal nanoribbons of controlled composition (where 0 ≤ x ≤ 1) can be synthesized by combining laser ablation with thermal evaporation. The nanoribbons exhibit lasing emission that can be continuously tuned within the ranges of 340-390 nm and 485-515 nm. These results suggest that Zn_x Cd_{1- x} S nanoribbon lasers of pre-selected "tunable" wavelengths between 340 and 515 nm may be achievable by tailoring the value of x.

Molecular Orientation and Film Morphology of Pentacene on Native Silicon Oxide Surface

The growth morphology and mechanism of pentacene films on native Si oxide surface have been studied by using high-resolution electron energy loss spectroscopy (HREELS), X-ray diffraction (XRD), and atomic force microscopy (AFM). Despite the good agreement between our own and the reported XRD results, the previous XRD interpretation that the pentacene molecules are tilt-standing on the substrate cannot explain our HREELS data. The HREELS results show that a substantial portion of the first two layers of pentacene molecules are tilted-standing or randomly oriented, whereas the upper-layer molecules are mostly lying flat to the substrate. AFM reveals that the first two layers of molecules form a flat and smooth surface, but the upper layers show a rough terrace structure with a mean-square roughness equal to the average thickness (without counting the first two layers). This relationship is explained by a theoretical model which assumes the pentacene molecules to remain on a particular molecule layer after arrival. The observed film growth morphology may have significant implication on the performance of electronic devices based on pentacene thin films. A plausible explanation was proposed for the discrepancy between the HREELS-indicated and the XRD-derived molecular orientations.

Stromal CD10 expression in mammary fibroadenomas and phyllodes tumours

BACKGROUND/AIMS

CD10 (CALLA) has recently been reported to be expressed in spindle cell neoplasia, and has been used to differentiate endometrial stromal sarcoma from leiomyoma and leiomyosarcoma. In the breast, myoepithelial cells express CD10, but there are few studies of the expression of CD10 in mammary fibroepithelial lesions.

METHODS

Stromal CD10 expression was studied in 181 mammary phyllodes tumours (102 benign, 51 borderline malignant, and 28 frankly malignant) and 33 fibroadenomas using immunohistochemistry, to evaluate whether differences in expression correlated with the degree of malignancy.

RESULTS

There was a progressive increase in the patients' age and tumour size, from fibroadenoma to phyllodes tumours with an increasing degree of malignancy (p < 0.001). Stromal CD10 expression was positive in one of 33 fibroadenomas, six of 102 benign phyllodes tumours, 16 of 51 borderline malignant phyllodes tumours, and 14 of 28 frankly malignant phyllodes tumours. The difference was significant (p < 0.001) and an increasing trend was established. Strong staining was seen in subepithelial areas with higher stromal cellularity and activity. Stromal CD10 expression had a high specificity (95%) for differentiating between benign lesions (fibroadenomas and benign phyllodes tumours) and malignant (borderline and frankly malignant) phyllodes tumours.

CONCLUSIONS

CD10 may be a useful adjunct in assessing malignancy in mammary fibroepithelial lesions.

Prognostic significance of DNA quantification by flow cytometry in ovarian tumors

OBJECTIVE

The objective of our study is to evaluate prognostic significance of DNA quantification by flow cytometry in ovarian tumor.

METHODS

A prospective analysis was performed on 56 ovarian tumor patients treated in the Yonsei Medical Center from Feb. 2000 to Jan. 2003.

RESULTS

Regarding the association between tumor grade and the DNA quantitative analysis, as tumor grade increased, the quantity of aneuploid cells and S-phase fraction (SPF) increased. In addition, SPF was increased significantly in the advanced staged patients (P=0.04) and SPF was significantly increased in aneuploid tumors (P=0.03). The overall survival rate was poor for patients with aneuploid tumors and for patients with tumors showing over SPF (10%).

CONCLUSION

Our data demonstrated that the prognosis was poor for patients with aneuploid cancers or increased SPF. Therefore, DNA quantification by flow cytometry may provide important information for predicting the prognosis of the disease.

Effects of milrinone on jugular bulb oxygen saturation and cerebrovascular carbon dioxide reactivity in patients undergoing coronary artery bypass graft surgery

BACKGROUND

Jugular bulb oxygen saturation (Sjv(o(2))) is a surrogate marker for global cerebral oxygenation. The effect of milrinone on Sjv(o(2)) and the cerebrovascular carbon dioxide reactivity (CCO2R) was investigated.

METHODS

Thirty patients scheduled for coronary artery bypass graft surgery (CABG) were studied prospectively. After sternotomy, normoventilation (at T(1); Pa(co(2))=4.7-5.0 kPa) and hyperventilation (at T(2); Pa(co(2))=3.3-3.7 kPa) were induced and the changes in Sjv(o(2)) (DeltaSjv(o(2))) and Pa(co(2)) (DeltaPa(co(2))), and DeltaSjv(o(2))/DeltaPa(co(2)) (CCO(2)R) were measured. After normoventilation was re-established (at T(3)), milrinone 50 microg kg(-1) was given (at T(4)), followed by hyperventilation (at T(5)), and DeltaSjv(o(2)), DeltaPa(co(2)) and CCO(2)R were measured.

RESULTS

After milrinone administration at normoventilation (T(3) and T(4)), cardiac index and mixed venous oxygen saturation increased, while mean arterial pressure and systemic vascular resistance index decreased, without a significant change in Sjv(o(2)). Before milrinone administration (T(1) and T(2)), hyperventilation decreased Pa(co(2)) and Sjv(o(2)), and DeltaSjv(o(2)) showed positive linear correlation with DeltaPa(co(2)). After milrinone administration (T(4) and T(5)), hyperventilation decreased Pa(co(2)) and Sjv(o(2)), and DeltaSjv(o(2)) showed positive linear correlation with DeltaPa(co(2)). There was no significant difference in CCO(2)R before and after milrinone administration (13.3 (5.7)% kPa(-1) and 12.3 (3.9)% kPa(-1), respectively).

CONCLUSIONS

Although milrinone induced significant haemodynamic changes, Sjv(o(2)) and CCO(2)R were unchanged during its administration.

Telephone reminders to reduce non-attendance rate for endoscopy

Non-attendance at clinics and endoscopy units wastes resources and lengthens waiting lists. In a previous study elsewhere, a substantial proportion of patients claimed to have forgotten their appointment. We therefore assessed the value of telephoning patients a week before their booked day-case endoscopy. An observation period of two months was followed by an intervention period of two months in which patients were contacted by phone and asked if they wished to come for their investigation. A maximum of three separate attempts were made to contact each patient. Patients cancelling the appointment were replaced by others on the reserve list. The non-attendance rate was expressed as the percentage of unused beds. During the observation period 56 patients were admitted and 18 beds were unused. During the intervention period it was possible to contact 73 of 88 patients and 8 of these cancelled. 87 beds were available and 83 patients were admitted. When clerical error, overbooking and failure to replace patients were taken into account, the non-attendance rate declined from 23.3% during the observation period to 5.7% during the intervention period (P<0.05). The intervention seemed more effective in reducing non-attendance in outpatients referrals (0/48) than in general practitioner referrals (5/40).

Twenty-year follow-up of the Carpentier-Edwards standard porcine bioprosthesis in the Oriental population

AIM

The 20-year period long-term results of porcine bioprosthetic valve use are limited. In addition, the majority of these reports come from Western countries. Given the scanty information reported in Oriental countries, this study was therefore designed to examine 20-year long-term results in patients who received a Carpentier-Edwards porcine bioprosthetic valve in an effort to contribute further information on the long-term clinical performance of porcine prosthetic valves from a viewpoint of results in the Oriental population.

METHODS

From July 1979 to April 2001, 82 patients received valve replacement with a standard Carpentier-Edwards porcine valve. There were 40 men and 42 women with a mean age of 42.3+/-15.1 years (range 16 to 73 years). Follow-up time extended more than 20 years (mean 10.9+/-3.2 years, range 0.5 to 21.5 years ) for a total of 719.5 patient-years.

RESULTS

The overall operative mortality was 16.9% (14 of 83 procedures). At 5, 10, 15, and 20 years, the actuarial survival rate of patients was 71.7%, 66.9%, 55.5%, and 44.4%, respectively. Actuarial estimates of freedom from structural valvular deterioration (SVD) at 5, 10, 15, and 17 years were 96.3%, 64.0%, 24.3%, and 24.3%, respectively; from reoperation 96.3%, 64.5%, 24.5%, and 24.5%; from operated valvular endocarditis 96.8%, 92.6%, 92.6%, and 92.6%; and from overall thromboembolism 96.3%, 88.5%, 67.2%, and 52.2%. In normal sinus rhythm, actuarial estimates of freedom from thromboembolism at 5, 10, 15, and 17 years were 100.0%, 100.0%, 81.8%, and 81.8%, respectively. Whereas for those in patients with atrial fibrillation, the estimates of freedom from thromboembolism were 94.5%, 82.4%, 57.7%, and 38.5%.

CONCLUSION

This study demonstrates the very satisfactory 20-year period long-term performance of freedom from bleeding events, thromboembolism (except in patients with atrial fibrillation), and valvular endocarditis in Oriental patients undergoing replacement with a porcine valve. However, the remarkable rate of SVD and reoperation ensued at 6 years after bioprosthesis implanted which does not differ from the series reported from Western countries.

Neurons derived from embryonic stem (ES) cells resemble normal neurons in their vulnerability to excitotoxic death

We determined whether embryonic stem (ES) cells could provide a model system for examining neuronal death mediated by glutamate receptors. Although limited evidence indicates that normal neurons can be derived from mouse ES cells, there have been no studies examining pathophysiological responses in mouse ES cell systems. Mouse ES cells, induced down a neural lineage by retinoic acid (RA), were found to have enhanced long-term survival when plated onto a layer of cultured mouse cortical glial cells. In these conditions, the ES cells differentiated into neural cells that appeared normal morphologically and displayed normal features of immunoreactivity when tested for neuron-specific elements. Varying the culture medium generated cultures of mixed neuronal/glial cells or enriched in oligodendrocytes. These cultures were viable for at least four weeks. Real-time PCR analysis of N-methyl-D-aspartate (NMDA) receptor subunits revealed an appropriate age-in-vitro dependent pattern of expression. Neurons derived from ES cells were vulnerable to death induced by a 24-h exposure to the selective glutamate receptor agonists NMDA, kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). This vulnerability to agonist-induced death increased with age in vitro, and related closely to expression of receptor subunits, as it does in cultured primary neurons. Experiments with selective receptor antagonists showed that glutamate receptors mediated the NMDA- and kainate-induced death. Neuronal differentiated ES cells therefore exhibited an excitotoxic response resembling that displayed by central nervous system (CNS) neurons. Thus, ES cells, which are very amenable to genetic manipulation, provide a valid system for studying glutamate receptor-mediated toxicity at the molecular level.

Multiple Congenital Malformation in a Holstein Calf

A 10-day-old male Holstein dairy calf with orthopaedic abnormalities was unable to stand but was alert with a suckle reflex. At necropsy, the calf showed multiple defects, including partial agenesis of the left rib plate, deformed left scapula, shortened left humerus, agenesis of the left kidney, atresia ani and scoliosis. The cause of these anomalies could not be determined. This report is the first to describe partial agenesis of ribs in a calf.

Telephone reminders to reduce non-attendance rate for endoscopy

Non-attendance at clinics and endoscopy units wastes resources and lengthens waiting lists. In a previous study elsewhere, a substantial proportion of patients claimed to have forgotten their appointment. We therefore assessed the value of telephoning patients a week before their booked day-case endoscopy. An observation period of two months was followed by an intervention period of two months in which patients were contacted by phone and asked if they wished to come for their investigation. A maximum of three separate attempts were made to contact each patient. Patients cancelling the appointment were replaced by others on the reserve list. The non-attendance rate was expressed as the percentage of unused beds. During the observation period 56 patients were admitted and 18 beds were unused. During the intervention period it was possible to contact 73 of 88 patients and 8 of these cancelled. 87 beds were available and 83 patients were admitted. When clerical error, overbooking and failure to replace patients were taken into account, the non-attendance rate declined from 23.3% during the observation period to 5.7% during the intervention period (P<0.05). The intervention seemed more effective in reducing non-attendance in outpatients referrals (0/48) than in general practitioner referrals (5/40).