Association between renal dysfunction and 3-year mortality in patients with acute first-ever ischemic stroke

OBJECTIVE

The influence of renal dysfunction on the clinical presentation and outcomes of patients with acute ischemic stroke is still controversial. We investigate the influence of renal dysfunction on the outcomes of patients with acute first-ever ischemic stroke.

METHODS

Nine-hundred thirty-four patients with acute first-ever ischemic stroke were enrolled and followed for 3 years. Renal function was assessed using the equation of the Modification Diet for Renal Disease for estimated glomerular filtration rate (eGFR). Serum creatinine levels were obtained within 3 days of acute stroke onset. Reduced eGFR was defined as eGFR<60ml/min/1.73m(2). Clinical presentation, risk factors for stroke, laboratory data, co-morbidities, and outcomes were recorded.

RESULTS

Total 264 patients (28.3%) had a reduced eGFR. The prevalence of older age, hypertension, and atrial fibrillation was significantly higher in patients with a reduced eGFR. Total anterior circulation syndrome occurred more frequently among patients with a reduced eGFR (P=0.010). Multivariate Cox regression revealed that a reduced eGFR is a significant predictor of 3-year mortality (HR=1.67, 95% CI=1.06-2.62, P=0.026).

CONCLUSION

Reduced eGFR during the acute stroke stage is associated with increased risk of 3-year mortality. Furthermore, risk of acute complications and poor functional outcomes following discharge was significantly higher in patients with a reduced eGFR.

Chondroitin Sulfate Proteoglycans Negatively Modulate Spinal Cord Neural Precursor Cells by Signaling Through LAR and RPTPσ and Modulation of the Rho/ROCK Pathway

Multipotent adult neural precursor cells (NPCs) have tremendous intrinsic potential to repair the damaged spinal cord. However, evidence shows that the regenerative capabilities of endogenous and transplanted NPCs are limited in the microenvironment of spinal cord injury (SCI). We previously demonstrated that injury-induced upregulation of matrix chondroitin sulfate proteoglycans (CSPGs) restricts the survival, migration, integration, and differentiation of NPCs following SCI. CSPGs are long-lasting components of the astroglial scar that are formed around the lesion. Our recent in vivo studies demonstrated that removing CSPGs from the SCI environment enhances the potential of transplanted and endogenous adult NPCs for spinal cord repair; however, the mechanisms by which CSPGs regulate NPCs remain unclear. In this study, using in vitro models recapitulating the extracellular matrix of SCI, we investigated the direct role of CSPGs in modulating the properties of adult spinal cord NPCs. We show that CSPGs significantly decrease NPCs growth, attachment, survival, proliferation, and oligodendrocytes differentiation. Moreover, using genetic models, we show that CSPGs regulate NPCs by signaling on receptor protein tyrosine phosphate sigma (RPTPσ) and leukocyte common antigen-related phosphatase (LAR). Intracellularly, CSPGs inhibitory effects are mediated through Rho/ROCK pathway and inhibition of Akt and Erk1/2 phosphorylation. Downregulation of RPTPσ and LAR and blockade of ROCK in NPCs attenuates the inhibitory effects of CSPGS. Our work provide novel evidence uncovering how upregulation of CSPGs challenges the response of NPCs in their post-SCI niche and identifies new therapeutic targets for enhancing NPC-based therapies for SCI repair.

A Technique to Study Meloidogyne arenaria Resistance in Agrobacterium rhizogenes-Transformed Peanut

A reliable peanut root transformation system would be useful to study the functions of genes involved in root biology and disease resistance. The objective of this study was to establish an effective protocol to produce composite plants mediated by Agrobacterium rhizogenes transformation. In total, 75% of transformed peanut seedlings produced an average of 2.83 transgenic roots per plant. Peanut seed had the highest germination rate after treatment in a chlorine gas chamber for 8 h compared with 16 h in chlorine gas or Clorox and mercuric chloride immersion treatments. High transformation efficiency was achieved when the wound site for A. rhizogenes inoculation was covered with vermiculite instead of enclosing the whole plant in a high humidity chamber. On average, 2.5 galls from Meloidogyne arenaria infection were formed per transgenic root from susceptible genotype TifGP-2. These data indicate that A. rhizogenes-transformed roots can be used to phenotype the host response to nematode challenge. Transformation of RLP-2, a candidate resistance gene for M. arenaria integrated into a silencing construct, did not alter the resistance response of Tifguard, even though downregulation of endogenous RLP-2 expression was detected in transformed roots. It is likely that RLP-2 is not the gene conditioning M. arenaria resistance in peanut.

Structure-based hybridization, synthesis and biological evaluation of novel tetracyclic heterocyclic azathioxanthone analogues as potential antitumor agents

A series of tetracyclic heterocyclic azathioxanthones were synthesized and evaluated for cell proliferations, topoisomerase inhibitions, and NCI-60 cell panel assay, respectively. Compounds 5, 7, 8, 16, and 19 were selected for topoisomerase assay after MTT assay. 7 not only showed cytotoxic effect (IC50 = 2.84 ± 0.64 μM) in PC-3 cells but also revealed topoisomerases inhibition with IC50 (10-25 μM) and increased apoptotic cleavage of PARP and caspase 3 activity. The overall of novel azathioxanthones with different cytostatic and cytotoxic activities should be further developed as new potential candidates for anticancer drugs.

NGAL can alternately mediate sunitinib resistance in renal cell carcinoma

PURPOSE

Serum NGAL is highly expressed in patients with advanced renal cancer treated with sunitinib. We investigated the role of NGAL in sunitinib resistance in renal cell carcinoma to identify potential tactics to overcome it.

MATERIALS AND METHODS

NGAL expression was correlated with sunitinib sensitivity. Vascular endothelial growth factor related upstream Ras, Erk1/2 and STAT1 phosphorylation activity in Caki-1 and NGAL transfected Caki-1 cells after sunitinib treatment was analyzed using Western blot. NGAL and vascular endothelial growth factor-A interaction with sunitinib therapeutic efficacy was monitored in renal cell carcinoma tumor xenografted mice by tumor growth inhibition, serum NGAL and vascular endothelial growth factor-a levels, and microscopic examination of tumor microvascular density.

RESULTS

Sunitinib cytotoxicity in various renal cell carcinoma cell lines was reversibly related to NGAL expression. Sunitinib showed the lowest 50% inhibitory concentration (5.53 μM) in Caki-1 cells, which had the lowest NGAL expression of these renal cell carcinoma cell lines. After sunitinib treatment adding NGAL inhibited Ras and Erk1/2 phosphorylation but activated STAT1α phosphorylation in Caki-1 cells and Caki-1 cells transfected with NGAL. In a xenograft mouse model sunitinib significantly inhibited tumor growth in Caki-1 mice. NGAL transfected Caki-1 mice had higher serum NGAL and lower vascular endothelial growth factor-A than Caki-1 mice. Microvascular density was decreased in Caki-1 mice with sunitinib treatment.

CONCLUSIONS

NGAL in tumor cells may show crosstalk with vascular endothelial growth factor-a and alternative activation in stimulating tumor growth during sunitinib treatment. It may become a therapeutic target to reverse sunitinib resistance in renal cell carcinoma.

Root Rot of Chinese Jujube (Ziziphus jujuba) Caused by Cytospora sacculus in China

Ziziphus jujuba Mill. (Rhamanaceae), commonly known as Chinese jujube, is a plant that is native to China and widely distributed in China and South Korea. Chinese jujube is a traditional Chinese medicine and food that has been used for thousands of years. From spring 2011 to spring 2012, Chinese jujube trees (<4 years old) from commercial orchards in Kashi and Akzo developed symptoms of severe wilting, chlorosis, and stunting. The taproot and lateral roots exhibited black, sunken, necrotic lesions, and progression of these symptoms eventually caused mortality of infected trees. In April 2011 and 2012, 15 trees with root rot symptoms were collected from different orchards, and a fungus was recovered consistently from symptomatic rhizome samples that had been surface-sterilized with 0.1% mercuric chloride and plated onto potato dextrose agar (PDA). Thirteen isolates were obtained. Colony growth on PDA was initially white but gradually turned grayish yellow-brown, with the lower side of the plate turning a deep yellow-brown. Colony texture was felty and slightly raised with no concentric growth zones. Pycnidia formed abundantly after 30 days, and each exuded a dull orange cirrhus containing conidia. The conidiomatal stromata were immersed in the bark, erumpent, discoid, convex to conical, and 1.53 ± 0.13 mm in diameter. Discs were dark brown or grey, nearly flat, circular, and up to 0.6 mm in diameter, with one to eight lateral ostioles. Ostioles were brown, 40 to 80 mm in diameter, and located above the disc surface. Locules were globose, with four to eight in a stroma, undivided, and did not share common walls. Conidia were hyaline, eguttulate, and allantoid, with sizes of 12 to 20 × 1.0 to 1.5 μm. The agar culture and conidiomatal stromata morphology were in accordance with descriptions of Cytospora sacculus (1,4). PCR amplification of the internal transcribed (ITS) spacer region of rDNA (using primers ITS1/4), combined with amplification of the β-tubulin gene (using primers BT1a/BT1b) (2,3), followed by sequencing of the amplified DNA, led to identification of isolate 6T-17 as Valsa ceratosperma (anamorph C. sacculus). The sequence of the ITS1-5.8s-ITS2 region of rDNA (GenBank Accession No. JX560175) matched the ITS sequence of V. ceratosperma Accession AB369475 with 99% similarity, and the β-tubulin gene sequence (KC840674) resulted in a 99% match with that of V. ceratosperma Accession EU219136. Mycelial plugs of a culture of each fungal isolate on PDA were inoculated onto 10 rhizomes of 2-month-old seedlings of Z. jujube, and maintained in a greenhouse at 25 to 30°C. Ten rhizomes of 2-month-old seedlings of Z. jujuba were inoculated with non-colonized PDA plugs as the control treatment. After 2 months, all inoculated seedlings showed chlorotic leaves and root rot symptoms similar to those observed in the original commercial orchards. No symptoms were observed on the control plants. The pathogen was reisolated successfully from symptomatic plants but not from the control plants, fulfilling Koch's postulates. To our knowledge, this is the first report of C. sacculus causing a root rot of Z. jujuba trees in China. References: (1) G. C. Adams et al. Stud. Mycol. 52:83, 2005. (2) G. M. Arruda et al. Plant Pathol. 54:53, 2005. (3) J. Baskarathevan et al. Eur. J. Plant Pathol. 132:549, 2012. (4) J. B. Kepley et al. J. Arbor. 26:326, 2000.

Association of hyponatremia in acute stroke stage with three-year mortality in patients with first-ever ischemic stroke

BACKGROUND

Hyponatremia is the most common electrolyte disorder in hospitalized patients, and is frequently a marker of a significant underlying disease. The prognostic value of hyponatremia in patients with acute first-ever ischemic stroke is not known. We aimed to analyze whether hyponatremia in the acute stroke stage contributed to the risk of mortality or recurrent stroke in these patients.

METHODS

We studied 925 patients presenting with acute first-ever ischemic stroke between 2002 and 2004. Sodium levels were obtained on arrival at the emergency room within 3 days of acute stroke onset. Hyponatremia was defined as a serum sodium concentration of 134 mmol/l or less. Clinical presentation, stroke risk factors, associated medical disease, and outcome were recorded. All patients were followed for 3 years for survival analysis. A multivariate Cox proportional hazards model was used to identify risk factors for 3-year mortality in these patients. We also constructed Kaplan-Meier survival curves, and compared groups with hyponatremia and normonatremia by means of log rank tests for significant differences.

RESULTS

Among the patients with acute first-ever ischemic stroke, 107 (11.6%) were hyponatremic. Among stroke risk factors, the prevalence of diabetes mellitus was significantly higher among hyponatremic patients (p < 0.001). Prevalence of chronic renal insufficiency was also higher in the hyponatremic group (p = 0.002). Clinical presentations, such as the length of acute ward stay, initial impaired consciousness, and clinical course in acute stroke were similar among normo- and hyponatremic patients. Among the complications, pneumonia and urinary tract infection were significantly higher in hyponatremic than in normonatremic patients. After multivariate logistic regression analysis, diabetes mellitus and chronic renal insufficiency were associated with hyponatremia in these patients. Kaplan-Meier analysis indicated that the survival rate was significantly lower in hyponatremic patients than in normonatremic patients (log rank test; p value <0.001). After multivariate Cox proportional hazards model analysis, hyponatremia was a significant predictor of 3-year mortality in these patients after adjustment for related variables (p value = 0.003, hazard ratio = 2.23, 95% confidence interval: 1.30-3.82).

CONCLUSION

Hyponatremia in the acute stroke stage is a predictor of 3-year mortality in patients with acute first-ever ischemic stroke that is independent of other clinical predictors of adverse outcome.

Receptor protein tyrosine phosphatase sigma regulates synapse structure, function and plasticity

The mechanisms that regulate synapse formation and maintenance are incompletely understood. In particular, relatively few inhibitors of synapse formation have been identified. Receptor protein tyrosine phosphatase σ (RPTPσ), a transmembrane tyrosine phosphatase, is widely expressed by neurons in developing and mature mammalian brain, and functions as a receptor for chondroitin sulfate proteoglycans that inhibits axon regeneration following injury. In this study, we address RPTPσ function in the mature brain. We demonstrate increased axon collateral branching in the hippocampus of RPTPσ null mice during normal aging or following chemically induced seizure, indicating that RPTPσ maintains neural circuitry by inhibiting axonal branching. Previous studies demonstrated a role for pre-synaptic RPTPσ promoting synaptic differentiation during development; however, subcellular fractionation revealed enrichment of RPTPσ in post-synaptic densities. We report that neurons lacking RPTPσ have an increased density of pre-synaptic varicosities in vitro and increased dendritic spine density and length in vivo. RPTPσ knockouts exhibit an increased frequency of miniature excitatory post-synaptic currents, and greater paired-pulse facilitation, consistent with increased synapse density but reduced synaptic efficiency. Furthermore, RPTPσ nulls exhibit reduced long-term potentiation and enhanced novel object recognition memory. We conclude that RPTPσ limits synapse number and regulates synapse structure and function in the mature CNS.

Higher leukocyte count is associated with higher risk of 3-year mortality in non-diabetic patients with first-ever ischemic stroke

Leukocyte count predicted the risk of first-time myocardial infarction and ischemic stroke. The aim of this study was to determine the role of elevated leukocyte count in non-diabetic patients admitted for acute first-ever ischemic stroke on clinical presentation and 3-year mortality. We studied 462 patients with acute first-ever ischemic stroke without diabetes mellitus or active infection at admission. Patients were classified into 2 groups according to their leukocyte count. A white blood cell (WBC) count ≥ 10,000/μL was defined as an elevated leukocyte count, otherwise as normal. Clinical presentation, risk factors for stroke, laboratory data, co-morbidities, and outcomes were recorded. 64 patients (13.9%) had elevated leukocytes. Multivariate logistic regression showed that an elevated platelet count was positively associated with the elevated leukocyte count, while a low serum sodium level was negatively associated with an elevated leukocyte count (P=0.008, P=0.003, respectively). An elevated leukocyte count was associated with a higher risk of a stroke in evolution (P=0.021). Multivariate Cox regression analysis revealed that an elevated leukocyte count is a significant predictor of 3-year mortality [P=0.010, HR=3.26 (1.33-7.98)]. In conclusion, higher leukocyte counts during the acute stroke stage are associated with increased risk of 3-year mortality in patients with acute, first-ever ischemic stroke.

[Prothymosin alpha interacts with C-terminal domain of histone H1 and dissociates p53-histone H1 complex]

A novel mode of the tumor suppressor protein p53 regulation, mediated by recruitment of the linker histone H1 to the promoters of p53 target genes leading to specific repression of p53-dependent transcription, has recently been uncovered. Yet, how this repression could be relieved is not clear. Previously, a histone-binding nuclear protein prothymosin alpha (ProTa) was shown to trigger a p53 response. The histone-binding region of ProTa was found to be essential for this effect, raising a possibility that ProTa stimulates p53-dependent transcription by dissociating the p53-histone H1 repressive complex. Here, we have shown that ProTa interacts with the same C-terminal domain of histone H1 as p53 does and, therefore, ProTa and p53 could compete for binding to histone H1. Furthermore, ProTa, when competent for histone H1 binding, is able to liberate p53 from the histone H1-p53 complex in vitro. In vivo, stimulation of p53-dependent transcription by ProTa correlates with ability of ProTa to interact with histone H1. Ectopic expression of histone H1 or its C-terminal ProTa-binding domain specifically suppresses the stimulating effect of ProTa on transcription of the p53-responsive reporter gene in cultured cells. These results are consistent with the model that ProTa may enhance p53 transcription activity by displacement of histone H1 from p53-H1 repressive complex.

The impact of smoking on the severity of acute ischemic stroke

OBJECTIVES

This study investigated the impact of smoking on the initial severity of acute ischemic stroke and examined its subsequent outcome.

METHODS

Patient data was collected from the Stroke Registry in the Chang Gung Healthcare System (SRICHS). A total of 2650 patients admitted for acute ischemic stroke from January to December 2009 were included. Baseline characteristics were compared between smokers and non-smokers. Factors affecting the initial severity and the recovery from neurological deficit were examined by logistic regression analysis. The patients were further divided according to stroke mechanism for subgroup analysis.

RESULTS

The total number of smokers and non-smokers was 817 (31.9%) and 1833 (69.1%), respectively. Univariate analysis showed that smokers had lower NIHSS scores on admission than did non-smokers (P<0.001). In subgroup analysis, smokers with small-vessel occlusions frequently had higher NIHSS scores on admission than did non-smokers (P=0.001). However, smokers with cardioembolic stroke had lower NIHSS scores on admission as compared to non-smokers (P=0.024). No subgroup had smoking as a significant factor for neurological recovery during hospitalization.

CONCLUSIONS

Smoking correlated with higher NIHSS scores on admission for small-vessel occlusion. Conversely, it was associated with lower NIHSS scores on admission for cardioembolism.

A new mathematical model for irradiance field prediction of upper-room ultraviolet germicidal systems

There has been an increasing interest in the use of upper-room ultraviolet germicidal irradiation (UVGI) system because of its proven disinfection effect for airborne microorganisms. To better design and explore further potential applications of UVGI systems, it is of critical importance to predict the spatial UV intensity in enclosures. In this paper, we developed a new mathematical model to predict spatial radiation intensity for upper-room ultraviolet germicidal irradiation systems. The detail geometries of the lamp and the reflector were removed and replaced by introducing a fictitious irradiation surface near louver slots. The view factor approach was applied to evaluate the UV irradiance in a three-dimensional space with different louver configurations. With this approach no detail meshing of the fixture is required and this leads to significant simplification of the entire systems from modeling perspectives. To validate the model, experiments were performed in a full-scale environmental controlled chamber in which one UVGI fixture was mounted on a sidewall. The UV irradiance was measured by a radiometer. The results predicted by the present model agree very well with the experimental measurements. Factors affect the accuracy of the model was also discussed.

Identification of PTPsigma as an autophagic phosphatase

Macroautophagy is a dynamic process whereby portions of the cytosol are encapsulated in double-membrane vesicles and delivered to the lysosome for degradation. Phosphatidylinositol-3-phosphate (PtdIns3P) is concentrated on autophagic vesicles and recruits effector proteins that are crucial for this process. The production of PtdIns3P by the class III phosphatidylinositol 3-kinase Vps34, has been well established; however, protein phosphatases that antagonize this early step in autophagy remain to be identified. To identify such enzymes, we screened human phosphatase genes by RNA interference and found that loss of PTPσ, a dual-domain protein tyrosine phosphatase (PTP), increases levels of cellular PtdIns3P. The abundant PtdIns3P-positive vesicles conferred by loss of PTPσ strikingly phenocopied those observed in cells starved of amino acids. Accordingly, we discovered that loss of PTPσ hyperactivates both constitutive and induced autophagy. Finally, we found that PTPσ localizes to PtdIns3P-positive membranes in cells, and this vesicular localization is enhanced during autophagy. We therefore describe a novel role for PTPσ and provide insight into the regulation of autophagy. Mechanistic knowledge of this process is crucial for understanding and targeting therapies for several human diseases, including cancer and Alzheimer's disease, in which abnormal autophagy might be pathological.

Recycling of spent filter backwash water using coagulation-assisted membrane filtration: effects of submicrometre particles on membrane flux

Membrane separation technology has been widely used for recycling of spent filter backwash water (SFBW) in water treatment plant. Membrane filtration performance is subject to characteristics of the particles in the SFBW. A bench-scale microfiltration (MF) coupled with pre-coagulation was set up to evaluate the recovery efficiency of SFBW. Effect of particle size distribution and zeta potential of the coagulated SFBW on the membrane filtration as well as the coagulation strategies were investigated. Pore clogging was more severe on the membrane with 1.0 mum pore size than on the membrane with 0.5 mum pore size due to the fact that submicrometre particles are dominant and their diameters are exactly closed to the pore size of the MF membrane. Pre-settling induced more severe irreversible fouling because only the submicrometre particles in the water become predominant after settling, resulting in the occurrence of more acute pore blocking of membrane. By contrast, pre-coagulation mitigates membrane fouling and improves membrane flux via enlarging particle size on membrane surface. The variations of zeta potential in response to coagulant dosing as well as fractal dimension were also compared with the performance of the subsequent filtration. The result showed that pre-coagulation induced by charge neutralization at the optimum dosage where the zeta potential is around zero leads to the optimal performance of the subsequent membrane filtration for SFBW recycling. At such condition, the fractal dimension of coagulated flocs reached minimum.

Pituitary adenoma apoplexy with initial presentation mimicking bacterial meningoencephalitis: a case report

Pituitary apoplexy is a rare but life-threatening disorder. Clinical presentation of this condition includes severe headache, impaired consciousness, fever, visual disturbance, and variable ocular paresis. Signs of meningeal irritation are very rare. However, if present and associated with headache, fever, and pleocytosis, meningeal irritation may lead to misinterpretation as infectious meningoencephalitis. To the best of our knowledge, pituitary apoplexy with an initial presentation mimicking infectious meningoencephalitis had rarely been reported in the literature. Here, we report a 57-year-old man who had acute severe headache, high fever, neck stiffness, disturbance in consciousness, and left ocular paresis. Laboratory data showed leukocytosis, an elevated C-reactive protein level, and neutrophilic pleocytosis in the cerebrospinal fluid. Because bacterial meningoencephalitis was suspected, empiric antibiotic therapy was administered but in vain. Further examinations indicated a diagnosis of pituitary adenoma with apoplexy. After the immediate administration of intravenous corticosteroid supplement and surgical decompression, the patient recovered.

Predictive factors of outcome and stroke recurrence in patients with unilateral atherosclerosis-related internal carotid artery occlusion

BACKGROUND

Clinical outcome of internal carotid artery (ICA) occlusion is highly variable and the reason is uncertain.

AIM

To study the predictive factors of clinical outcome and stroke recurrence in patients with ischemic stroke associated with unilateral atherosclerosis-related ICA occlusion.

SETTINGS AND DESIGN

Prospective study in neurology department of a single hospital.

MATERIALS AND METHODS

We prospectively studied 66 patients who suffered from first-ever ischemic stroke associated with unilateral atherosclerosis-related ICA occlusion over a period of two years. The end point was death or stroke recurrence.

STATISTICAL ANALYSIS

Chi-square or Fisher's exact test was used to analyze predictors of early functional outcome. Multivariate analysis was used to analyze predictors of death or stroke recurrence within two years.

RESULT

Higher age (>or=70 years) predicted a worse functional outcome (P=0.049). Total anterior circulation syndrome (TACS) was associated with a poor functional outcome (P<0.001), but lacunar syndrome had a better outcome (P=0.001). Stroke in evolution predicted a poor outcome (P=0.001), while those with symptom improvement had a better outcome (P=0.016). Pneumonia predicted a poor outcome (P=0.021). Five patients expired and 22 patients suffered from recurrent stroke in the following 24 months. Previous transient ischemic attack (TIA) and anemia were associated with a higher risk of death or recurrent stroke within two years (P=0.036, P=0.012).

CONCLUSION

High age, TACS, stroke in evolution and pneumonia were predictors for poor functional outcome. Previous TIA and anemia were predictors for death and recurrent stroke within two years.

Modification of 15-akylidene andrographolide derivatives as alpha-glucosidase inhibitor

15-Alkylidene andrographolide derivatives were specific alpha-glucosidase inhibitors. Semi-synthetic studies of these derivatives led to new alpha-glucosidase inhibitors. Their alpha-glucosidase inhibitory activity was evaluated. Bioactivity results indicated that most of the derivatives were excellent alpha-glucosidase inhibitors. Among them, 6c displayed the best alpha-glucosidase inhibitory bioactivity with an <span lang="EN-US">IC(50) value of 8.3 </span><span lang="EN-US" style="font-size: 10.5pt; font-family: Symbol;">m</span><span lang="EN-US">M.</span>

Reorganization of cytoskeleton induced by 5-aminolevulinic acid-mediated photodynamic therapy and its correlation with mitochondrial dysfunction

BACKGROUND AND OBJECTIVES

This study investigated the early cellular events which occurred after mitochondrial photodamage induced by 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT).

STUDY DESIGN/MATERIALS AND METHODS

Subcellular localization of protoporphyrin IX (PpIX) in NIH3T3 cells was studied by confocal microscopy. Mitochondrial damage was assessed by measuring mitochondrial transmembrane potential and ATP contents, and confirmed by characteristic appearance on transmission electron microscopy. Cellular adhesion was measured by the level of resistance to trypsinization. Cytoskeletal studies were performed by fluorescent staining of cytoskeletal components.

RESULTS

Following ALA-PDT, mitochondrial damage was found in NIH3T3 cells as judged by the decrease of membrane potential and ATP contents. Mitochondrial photodamage was further confirmed by electron microscopy. Resistance to trypsinization after ALA-PDT was shown to be light dose-dependent. The increase of cellular adhesion after ALA-PDT was correlated with mitochondrial photodamage and reorganization of cytoskeletal components in NIH3T3 cells.

CONCLUSIONS

This study has demonstrated that mitochondrial dysfunctions induced by ALA-PDT results in alterations of cellular morphology and cellular adhesion.

Alpha-methylacyl-CoA racemase: a multi-institutional study of a new prostate cancer marker

AIM

To test whether alpha-methylacyl-CoA racemase (AMACR) is a sensitive and specific marker of prostate cancer.

METHODS AND RESULTS

The expression levels of AMACR mRNA were measured by real-time polymerase chain reaction. A total of 807 prostatic specimens were further examined by immunohistochemistry specific for AMACR. Quantitative immunostaining analyses were carried out by using the ChromaVision Automated Cellular Imaging System and the Ariol SL-50 Imaging System, respectively. AMACR mRNA levels measured in prostatic adenocarcinoma were 55 times higher than those in benign prostate tissue. Of 454 cases of prostatic adenocarcinoma, 441 were positive for AMACR, while 254 of 277 cases of benign prostate were negative for AMACR. The sensitivity and specificity of AMACR immunodetection of prostatic adenocarcinomas were 97% and 92%, respectively. Both positive and negative predictive values were 95%. By automatic imaging analyses, the AMACR immunostaining intensity and percentage in prostatic adenocarcinomas were also significantly higher than those in benign prostatic tissue (105.9 versus 16.1 for intensity, 45.7% versus 0.02% and 35.03% versus 4.64% for percentage, respectively).

CONCLUSIONS

We have demonstrated the promising features of AMACR as a biomarker for prostate cancer in this large series and the potential to develop automated quantitative diagnostic tests.

Loss of p16 expression is of prognostic significance in locally advanced prostate cancer: an analysis from the Radiation Therapy Oncology Group protocol 86-10

PURPOSE

The retinoblastoma (RB) cell cycle regulatory pathway is known to be deregulated in virtually all known human tumors. The protein product of the RB gene, pRB, and its upstream regulator, p16, are among the most commonly affected members of this pathway. We investigated the prognostic significance of both pRB and p16 expression in locally advanced prostate cancers, from patients treated on the Radiation Therapy Oncology Group (RTOG) protocol 86-10.

MATERIALS AND METHODS

Sixty-seven cases from RTOG 86-10 had immunohistochemically stained slides, judged interpretable for both p16 and pRB, available for analysis. Median follow-up was 8.9 years (range, 6.0 to 11.8 years) for surviving patients. Staining for each marker was then correlated with overall survival, local progression, distant metastasis, and disease-specific survival.

RESULTS

Loss of p16 expression, as defined by expression was significantly associated with reduced overall survival (P =.039), disease-specific survival (P =.006), and higher risk of local progression (P =.0007) and distant metastasis (P =.026) in the univariate analysis. In the multivariate analysis, loss of p16 was significantly associated with reduced disease-specific survival (P =.0078) and increased risk of local failure (P =.0035) and distant metastasis (P =.026). A borderline association with reduced overall survival (P =.07) was also evident. Loss of pRB was associated with improved disease-specific survival on univariate (P =.028) and multivariate analysis (P =.043), but carried no other significant outcome associations.

CONCLUSION

Loss of p16 is significantly associated with adverse clinical outcome in cases of locally advanced prostate cancer.

Involvement of cholecystokinin receptor in the inhibition of gastrointestinal motility by estradiol in ovariectomized rats

BACKGROUND

The effects of estradiol benzoate (EB) on gastric emptying, gastrointestinal transit and plasma levels of cholecystokinin (CCK) were studied in ovariectomized rats.

METHODS

Gastrointestinal motility was assessed in rats 15 min after intragastric instillation of a test meal containing charcoal and Na2 51CrO4. Gastric emptying was determined by measuring the amount of radiolabeled chromium contained in the small intestine as a percentage of the initial amount received. Gastrointestinal transit was evaluated by calculating the geometric center of distribution of the radiolabeled marker. Blood samples were collected for E2 and CCK radioimmunoassay.

RESULTS

After treatment of EB (4-25 microg/kg), gastric emptying and gastrointestinal transit were inhibited, whereas plasma concentrations of E2 and CCK were increased in a dose-dependent manner. The selective CCK(A) receptor antagonists, devazepide and lorglumide, effectively attenuated the EB-induced inhibition of gastric emptying and gastrointestinal transit. L-365,260, a selective CCK(B) receptor antagonist, did not alter the EB-induced inhibition of gastric emptying and gastrointestinal transit.

CONCLUSIONS

The results suggest that EB inhibits gastric emptying and gastrointestinal transit in ovariectomized rats via a mechanism involving CCK stimulation and CCK(A) receptor activation.

Molecular genetic analysis of the NF2 gene in young patients with unilateral vestibular schwannomas

Neurofibromatosis type 2 (NF2) must be suspected in patients presenting with a unilateral vestibular schwannoma at a young age who are therefore at theoretical risk of developing bilateral disease. We identified 45 patients aged 30 years or less at the onset of symptoms of a unilateral vestibular schwannoma. Molecular genetic analysis of the NF2 gene was completed on peripheral blood samples in all 45 and on 28 tumour samples. No pathogenic NF2 mutations were identified in any of the blood samples. NF2 point mutations were identified in 21/28 (75%) tumour samples and loss of heterozygosity (LOH) in 21/28 (75%) tumour samples. Both mutational hits were identified in 18/28 (65%) tumour samples. In one multilobular tumour, one (presumably first hit) mutation was confirmed which was common to different foci of the tumour, while the second mutational event differed between foci. The molecular findings in this patient were consistent with somatic mosaicism for NF2 and the clinical diagnosis was confirmed with the presence of two meningiomas on a follow up MRI scan. A further patient developed a contralateral vestibular schwannoma on a follow up MRI scan in whom neither of the truncating mutations in the vestibular schwannoma were present in blood. It is important when counselling patients with unilateral vestibular schwannomas to identify (1) those at risk of bilateral disease, (2) those at risk of developing other tumours, and (3) other family members at risk of developing NF2. Comparing tumour and blood DNA cannot exclude mosaicism in the index case and cannot, therefore, be used to predict those at risk of developing further tumours. However, identification of both mutations or one mutation plus LOH in the tumour and exclusion of those mutations in the blood samples of the sibs or offspring of the affected case may be sufficient to render further screening unnecessary in these relatives.

Strain compounding: spatial resolution and performance on human images

Compounding has long been used to reduce speckle brightness variations by incoherently combining partially correlated measurements of the same image object. Conventionally, decorrelation between measurements is introduced by imaging from different spatial positions (i.e., spatial compounding) or within different frequency ranges (i.e., frequency compounding). An alternative compounding approach based on speckle decorrelation of an object under different strain conditions was recently proposed. The new approach was referred to as strain compounding. Speckle correlation of strain compounding was previously analyzed using simulations and radiofrequency (RF) data from a gelatin-based phantom. Results indicated that effective speckle reduction is possible at strains potentially achievable in certain clinical situations. In this paper, performance of strain compounding is further analyzed. Potential degradation in spatial resolution of strain compounding is compared to that of conventional approaches using computer simulations. Results show that strain compounding potentially can achieve the same level of speckle reduction, with less degradation in spatial resolution if a large compression can be applied. Performance of strain compounding is also tested using postdetection human images acquired by a commercial imaging system. Two-dimensional (2-D) speckle tracking is performed to correct for tissue motion resulting from external compression and to ensure that the images to be compounded are spatially matched. Thyroid images show that speckle brightness variations can be effectively reduced without significant degradation in spatial resolution. Speckle reduction in liver imaging is also demonstrated. However, speckle reduction is not as significant as in thyroid imaging, due to the fact that a large compression cannot be achieved.

Sesquiterpenoid constituents of the liverworts Lepidozia fauriana and Lepidozia vitrea

The sesquiterpene constituents of the essential oils of the Taiwanese liverworts Lepidozia fauriana and L. vitrea were investigated. 11,12-Dihydrochiloscyphone and 7,10-anhydro-11,12-dihydrochiloscypholone were isolated from L. fauriana and spectroscopically characterised together with their hydrogenation products. From the same species three amorphane derivatives amorpha-4,9-dien-14-al, amorpha-4,9-dien-2-ol and 7,14-anhydroamorpha-4,9-diene, and from L. vitrea two oxygenated elemanes, namely 7-acetoxy-elema-1,3-dien-8-ol and elema-1,3-dien-7-ol, were isolated and identified. Structure elucidation was carried out by NMR spectroscopy and chemical correlations in conjunction with enantioselective gas chromatography were utilized to establish absolute configurations.

Retrovirus-mediated transfer of prothymosin gene inhibits tumor growth and prolongs survival in murine bladder cancer

To explore the potential use of prothymosin alpha(ProT), a putative thymic hormone, in gene therapy for bladder cancer, we generated a replication-defective recombinant retroviral vector encoding ProT and tested its antitumor effect on the MBT-2 murine bladder cancer. C3H/HeN mice injected with MBT-2 cells in conjunction with retroviruses encoding ProT exhibited smaller tumor mass, lower tumor incidence and higher survival rate, as well as higher antitumor cytotoxic activities compared with those injected with control viruses. However, such effects were not observed in severe combined immunodeficiency mice, suggesting that ProT exerts antitumor effects through its immunomodulatory activities. Cell growth in monolayer culture and colony formation in soft agar were enhanced in ProT gene-modified MBT-2 clones, and such growth-promoting activities of ProT could be reversed if its nuclear localization signal (NLS) was deleted. To circumvent the proliferation-promoting effect of ProT on tumor cells, a retroviral vector encoding ProT lacking NLS was constructed. Our results showed that retroviruses encoding NLS-deleted ProT was more efficacious than those encoding wild-type ProT in prolonging survival of tumor-bearing mice. This is the first report indicating that ProT, in particular NLS-deleted ProT, delivered by retroviral vectors may be further explored for the treatment of bladder cancer.

Ascending cholangitis provokes IL-8 and MCP-1 expression and promotes inflammatory cell infiltration in the cholestatic rat liver

BACKGROUND/PURPOSE

Postoperative cholangitis is one of the most common complications after bile duct reconstruction. The pathogenesis and early consequences of ascending cholangitis still are unidentified.

METHODS

Male Sprague-Dawley rats were divided into 5 treatment groups: control (n = 4), blood sampling and liver biopsy only; group I, [BDL/Eschericha coli; n = 6], ligation of common bile duct (BDL) for a week, followed by Roux-en-Y choledochojejunostomy (RYCJ) and injection of E coli (ATCC 25922) into Roux limb after 24 hours; group II, [BDL/NS; n = 5], same procedures as in group I, with injection of normal saline (NS) into Roux limb; group III, [SBDL/E coli; n = 6], primary RYCJ was constructed 1 week after sham ligation of common bile duct (SBDL) followed by the same treatment as group I; Group IV, [SBDL/N.S; n = 6], same procedures as in group III, but injecting NS into Roux limb. All animals were killed after 24 hours of treatment. Blood was sampled for culture and serum cytokine levels. The liver was harvested for quantitative bacterial culture, as well as for MCP-1, interleukin (IL)-8 (CINC in the rat) and transforming growth factor beta1 mRNA expression by reverse transcriptase polymerase chain reaction (RT-PCR) and for immunohistochemistry. The choledochojejunostomy was resected for culture. Serum cytokine levels were detected by ELISA kits.

RESULTS

A significant increase of E coli ATCC 25922, occurred in the livers of group I rats, compared with group IV (P =.037). MCP-1 expression increased in all groups, compared with control (P =.000). The IL-8 mRNA expression was significantly higher in group I than in control (P =.021). The expression of TGF-beta1 mRNA was similar among the groups (P =.361), consistent with the immunohistochemistry results. The serum MCP-1 and IL-8 levels were higher in the 4 groups than in the control (P =.000) and were significantly higher in group I than in group IV (P =.001).

CONCLUSIONS

This study found that a significant colonization of E coli of the same strain was present in the cholestatic rat liver injected into the Roux limb, which was associated with a higher expression of liver MCP-1 and IL-8 mRNA, a significant increase of serum MCP-1 and IL-8, and a more evident inflammatory cell infiltration into the porta hepatis.

Clinical patterns among invasive pulmonary aspergillosis patients with and without recent intensive immunosuppressive therapy

BACKGROUND AND PURPOSE

Invasive pulmonary aspergillosis (IPA) is usually an acute life-threatening infection in cancer patients receiving chemotherapy and in organ transplant recipients receiving immunosuppressive therapy. In some immunocompetent patients, IPA has a chronic and indolent clinical course. We compared the clinical patterns among IPA patients who had received recent intensive immunosuppressive therapy (RIIT) and those who had not (N-RIIT).

METHODS

We reviewed the medical records of patients with a diagnosis of IPA made between 1992 and 1999. RIIT was defined as chemotherapy or high-dose corticosteroid therapy (at least 500 mg/d methylprednisolone, or equivalent, for at least 3 d) within 2 weeks before the onset of symptoms. RIIT patients were divided into those with and without malignancy. We compared clinical characteristics including age, sex, chest image patterns, diagnostic methods, culture results, treatment conditions, mortality, and recurrence rate in IPA patients: RIIT versus N-RIIT, and RIIT with and without malignancy.

RESULTS

A total of 24 patients with IPA, 17 patients who had received RIIT and seven patients who had not (N-RIIT), were included. In the RIIT group, 11 patients had malignancy and six did not. No significant differences in gender, chest image patterns, diagnostic methods, and culture results were found between the RIIT and N-RIIT groups. The N-RIIT group was older and was treated significantly later after the onset of symptoms than the RIIT group (mean +/- standard deviation, SD, 89.43 +/- 129.47 vs 9.70 +/- 9.33 d, p = 0.018). Only one of the seven N-RIIT patients died, while nine of the 17 RIIT patients died (p = 0.08). Among the RIIT patients, five of the six without malignancy died, while four of the 11 patients with malignancy died. IPA recurred in seven of the eight RIIT patients, all of whom had malignancy, but in none of the six N-RIIT patients during a similar follow-up period (mean +/- SD, 16.3 +/- 18.9 vs 27.0 +/- 54.5 mo, p = 0.505).

CONCLUSIONS

No differences were noted in image and culture studies between RIIT and N-RIIT IPA patients. RIIT IPA patients had acute and fulminant clinical courses, especially patients without malignancy, even though they received treatment with a mean duration of about 10 days starting from the onset of symptoms. All patients with malignancy undergoing further chemotherapy had recurrence of IPA. N-RIIT IPA patients had chronic clinical courses, a trend of lower mortality rate even with delayed diagnosis, and no recurrence.

Lithium-pilocarpine-induced status epilepticus in immature rats result in long-term deficits in spatial learning and hippocampal cell loss

Rat pups age of 14 postnatal day (P14) were subjected to lithium-pilocarpine (Li-PC) model of status epilepticus (SE). Control rats (n=6) were given an equivalent volume of saline intraperitoneally. Behavioral testing began on P60 including the Morris water maze, the radial arm maze, and the rotarod test. Brain were then analyzed with cresyl violet stain for histological lesions and evaluated for mossy fiber sprouting with the Timm stain. We observed spatial memory deficits both in the Morris water maze and radial arm maze in Li-PC-treated rat. There was no motor impairment in Li-PC-treated rat by the rotarod test. Two of six Li-PC-treated rats showed cell loss in hippocampal CA1 subfield. The Timm staining pattern was similar in both control and Li-PC-treated rats. Result of this study suggests that Li-PC-induced SE in immature rats cause long-term cognitive deficit and permanent cell loss in hippocampal CA1, but spare motor impairment.

Cables enhances cdk2 tyrosine 15 phosphorylation by Wee1, inhibits cell growth, and is lost in many human colon and squamous cancers

Cyclin-dependent kinase 2 (cdk2) is a small serine/threonine kinase that regulates cell cycle progression. Cdk2 activity is tightly controlled by several mechanisms, including phosphorylation and dephosphorylation events. Cables is a recently described novel cdk-interacting protein. In proliferating cells, Cables was predominantly localized in the nucleus by cell fractionation and immunostaining. Expression of Cables in HeLa cells inhibited cell growth and colony formation. Cables enhanced cdk2 tyrosine 15 phosphorylation by the Wee1 protein kinase, an inhibitory phosphorylation, which led to decreased cdk2 kinase activity. The gene encoding Cables is located on human chromosome 18q11-12, a site that is frequently lost in squamous, colon, and pancreas cancers. We found that Cables was strongly expressed in normal human epithelial cells including squamous and glandular mucosa. Breast and pancreatic cancers show strong Cables expression; however, loss of Cables expression was found in approximately 50-60% of primary colon and head and neck cancer specimens. Lack of Cables expression was associated with loss of heterozygosity on chromosome 18q11. The data provide evidence for a Cables-mediated interplay between cdk2 and Wee1 that leads to inhibition of cell growth. Conversely, loss of Cables may cause uncontrolled cell growth and enhance tumor formation.

Helicobacter pylori infection in recurrent abdominal pain in children--a prospective study

A total of 40 children was recruited to assess the role of Helicobacter pylori infection in children with recurrent abdominal pain syndrome. Among 40 children, seven (17.5%) cases were confirmed to have H. pylori infection. All H. pylori-positive patients had active chronic gastritis histologic findings (p < 0.0001); however, the majority of the H. pylori-negative patients had minimal to mild gastritis histologic findings (p = 0.001). Grossly, chronic gastritis picture was present in all children infected with H. pylori and antral nodular gastropathy present in 43%. 71% of H. pylori-positive patients had elevated anti-H. pylori IgG titer; however, 15% in H. pylori-negative patients (p = 0.006). Serum H. pylori assay had a sensitivity of 71% and specificity of 85%; however, sensitivity and specificity of rapid urease test were 86% and 100% respectively. Antral nodularity is a specific, peculiar endoscopic finding of children infected with H. pylori (p = 0.004). Although the present study suggests that H. pylori-related chronic gastritis may play an etiological role in a subgroup of children with RAP syndrome, but the routine screening of H. pylori infection in children with RAP is not recommended, since no compelling data support the significant association between H. pylori infection and RAP syndrome.

Prothymosin alpha enhances protective immune responses induced by oral DNA vaccination against pseudorabies delivered by Salmonella choleraesuis

Previously, we showed that vaccination with the glycoprotein D (gD) gene of pseudorabies virus (PrV) delivered by Escherichia coli induced protective immune responses. In this study, we report that oral DNA vaccination with attenuated Salmonella choleraesuis carrying the PrV gD gene conferred protective immunity in mice against PrV. Moreover, co-delivery of the prothymosin alpha gene carried by S. choleraesuis enhanced the vaccine efficacy. Our results thus demonstrate for the first time, to our knowledge, the effectiveness of oral DNA vaccination using S. choleraesuis as a delivery vehicle and the potential usefulness of prothymosin alpha as a DNA vaccine adjuvant.

Binding of ATP to the fructose-2,6-bisphosphatase domain of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase leads to activation of its 6-phosphofructo-2-kinase

To understand the mechanism by which the activity of the 6-phosphofructo-2-kinase (6PF-2K) of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is stimulated by its substrate ATP, we studied two mutants of the enzyme. Mutation of either Arg-279, the penultimate basic residue within the Walker A nucleotide-binding fold in the bisphosphatase domain, or Arg-359 to Ala eliminated the activation of the chicken 6PF-2K by ATP. Binding analysis by fluorescence spectroscopy using 2'(3')-O-(N-methylanthraniloyl)-ATP revealed that the kinase domains of these two mutants, unlike that of the wild type enzyme, showed no cooperativity in ATP binding and that the mutant enzymes possess only the high affinity ATP binding site, suggesting that the ATP binding site on the bisphosphatase domain represents the low affinity site. This conclusion was supported by the result that the affinity of ATP for the isolated bisphosphatase domain is similar to that for the low affinity site in the wild type enzyme. In addition, we found that the 6PF-2K of a chimeric enzyme, in which the last 25 residues of chicken enzyme were replaced with those of the rat enzyme, could not be activated by ATP, despite the fact that the ATP-binding properties of this chimeric enzyme were not different from those of the wild type chicken enzyme. These results demonstrate that activation of the chicken 6PF-2K by ATP may result from allosteric binding of ATP to the bisphosphatase domain where residues Arg-279 and Arg-359 are critically involved and require specific C-terminal sequences.

Effect of local anesthetics on patient recovery after transrectal biopsy

OBJECTIVES

To determine the analgesic efficacy of local anesthetics injected lateral to the seminal vesicles before prostate biopsy, during and immediately after the procedure, because pain is a common side effect of transrectal ultrasound-guided prostate biopsy.

METHODS

Patients were randomized to receive 5 mL of either 1% lidocaine or sterile normal saline injected (under ultrasound guidance) lateral to the seminal vesicles bilaterally before performance of the prostate biopsies, with the patient and physician unaware of the treatment group. Five minutes after the injection, a series of 12 prostate biopsies were performed. A visual analog scale (VAS) for pain at rest and with activity was obtained before the biopsy (preprocedure VAS) and immediately (intraprocedure VAS) and 30 minutes (postprocedure VAS) after the biopsy. Surveys examining the patients' expectations for biopsy pain were administered before and immediately after the biopsy.

RESULTS

No significant differences were found between the groups with regard to demographic data, VAS pain scores at rest and with activity, and survey results.

CONCLUSIONS

Injection of lidocaine lateral to the seminal vesicles before prostate biopsy did not diminish biopsy-associated pain.

Vaccination with the glycoprotein D gene of pseudorabies virus delivered by nonpathogenic Escherichia coli elicits protective immune responses

Attenuated intracellular bacteria, such as Salmonella and Shigella, have been exploited to act as gene delivery vectors. In this study, we report that nonpathogenic, live Escherichia coli can be used for the delivery of DNA vaccines in vivo, leading to generation of immune responses against plasmid-encoded foreign antigens. The pseudorabies virus (PrV) DNA vaccine carrying the glycoprotein D (gD) gene delivered by E. coli was able to induce protective immune responses in mice against a lethal PrV challenge. Co-delivery of E. coli carrying plasmid DNA encoding prothymosin alpha enhanced cellular immune responses to the PrV DNA vaccine delivered by E. coli. Our results suggest that nonpathogenic E. coli may be used as a vector for DNA vaccines in veterinary uses.

Structure determination of the Si3N4/Si(111)- (8 x 8) surface: a combined study of Kikuchi electron holography, scanning tunneling microscopy, and ab initio calculations

A comprehensive atomic model for the reconstructed surface of Si3N4 thin layer grown on Si(111) is presented. Kikuchi electron holography images clearly show the existence of adatoms on the Si3N4(0001)/Si(111)-(8x8) surface. Compared with the ab initio calculations, more than 30 symmetry-inequivalent atomic pairs in the outmost layers are successfully identified. Scanning tunneling microscopy (STM) images show diamond-shaped unit cells and nine adatoms in each cell. High-resolution STM images reveal extra features and are in good agreement with the partial charge density distribution obtained from total-energy calculations.

Regional anesthesia and anticoagulation

The perioperative use of neuraxial techniques in the presence of anticoagulation is a controversial issue. There are significant pharmacokinetic differences between anticoagulants that will affect the timing of neuraxial needle insertion or catheter removal. The pharmacologic profiles of commonly used anticoagulants in the perioperative period are reviewed. Studies examining the use of neuraxial techniques in the presence of various anticoagulants are reviewed and evaluated in the context of the American Society of Regional Anesthesia consensus statements.

[The effect of hypoxic preconditioning on myocardium energy metabolism]

AIM AND METHODS

To evaluate the protective effects of hypoxic preconditioning (HPC) on myocardial energy metabolism, Langendorff-perfused hearts, exposed to HPC, were subjected to hypoxia/reoxygenation (5/10 min). 31P NMR was used to sequentially follow the time courses of high energy phosphates (HEP) contents and intracellular pH (pHi) of the rat myocardium.

RESULTS

The Contents of Phosphocreatine (PCr), Adenosine Triphosphate (ATP) and the PCr/Pi (inorganic phosphate) ratios decreased during 30 min hypoxia, but the reduction was slower for the HPC group compared with Control. Reoxygenation induced recovery of myocardial HEP in both groups, HPC enhanced t he recovery especially in initial stage o f reoxygenation. However, pHi change was not significant for HPC group in this experiment.

CONCLUSION

HPC improves the myocardial energy metabolism level during prolonged hypoxia and subsequent reoxygenation and protects myocardium against hypoxia/reoxygenation injury.