Changes in high-sensitivity C-reactive protein levels and metabolic indices according to grip strength in Korean postmenopausal women

OBJECTIVE

This study aimed to investigate the changes in high-sensitivity C-reactive protein (hs-CRP) level and metabolic indices such as blood pressure, serum lipid level and serum glucose level according to grip strength in postmenopausal women.

METHOD

Data from participants (postmenopausal women) in the Seventh Korea National Health and Nutrition Examination Survey 2018 were analyzed. Absolute handgrip strength was the sum of the maximal grip strength of both hands, and relative handgrip was calculated as absolute handgrip divided by the body mass index. We performed linear regression analysis after adjusting for confounders to assess the influence of grip strength on hs-CRP level and metabolic indices.

RESULTS

Linear regression analysis showed that after adjusting for confounders, with an increased absolute grip strength, systolic blood pressure and hs-CRP levels were decreased; however, the changes were not significant for the remaining indices. Relative grip strength was associated with hs-CRP levels and metabolic indices. With a high relative grip strength, hs-CRP, blood pressure, fasting blood glucose, hemoglobin A1c and triglyceride levels were decreased, while the high-density lipoprotein cholesterol level was increased.

CONCLUSION

Our study evaluated the overall health status using grip strength in postmenopausal women. The grip strength adjusted by body size was suitable in evaluating the overall health status, including inflammatory and metabolic indices. Additionally, increased grip strength was associated with a better health status in postmenopausal women.

A novel energy efficient path for nitrogen fixation using a non-thermal arc

Plasma-assisted nitrogen fixation is a promising sustainable and clean alternative to the classical Haber-Bosch process. However, the high energy consumption and low production rate of plasma-assisted nitrogen fixation limit its application. This study shows that the non-thermal (non-equilibrium) enhancement of the arc plasma significantly reduces the energy consumption of nitrogen fixation. The highest energy efficiency with high NO selectivity is observed with a low specific energy input (SEI). However, the highest production rate is reached at a high SEI. The studied process offers high NO selectivity (up to 95%) with low energy consumption (∼48 GJ per tN) at 0.1 kJ L-1 SEI, which is much lower than the previously reported value of plasma-assisted atmospheric nitrogen fixation and is close to that of the Haber-Bosch process.

Developing clinical cut-off scores for the university of California San Diego performance-based skills assessment in patients with schizophrenia

This study aimed to obtain University of California San Diego Performance-based Skill Assessment (UPSA) cut-off scores for the purpose of severity classification and to expand the clinical utility of the UPSA for the evaluation of cognitive function in patients with schizophrenia. In total, 191 patients with schizophrenia were recruited. The UPSA, Positive and Negative Symptom Scale (PANSS), Clinical Global Impression-Schizophrenia Scale (CGI-SCH), and Global Assessment Functioning Scale (GAF) were used for the evaluation. The cognitive symptoms item of the CGI-SCH was used as a reference and the subjects were divided into three groups: mild, moderate, and severe. The sensitivity and specificity of the UPSA were analyzed by receiver operating characteristic curves. There were significant differences in the UPSA, CGI-SCH, PANSS, and GAF scores among the groups. In the mild and moderate groups, a UPSA score of 59 was identified as the optimal cut-off score, and a score of 41 was identified as the optimal cut-off score in the moderate and severe groups. Severity can be classified using the UPSA score as follows: ≥ 60 for mild, 41-59 for moderate, and ≤ 40 for severe. The UPSA could be used to assess the degree of daily living dysfunction in patients with schizophrenia.

The effect of anticholinergic burden on cognitive and daily living functions in patients with schizophrenia

OBJECTIVE

This study aimed to explore the association between medication-associated anticholinergic burden and cognitive and daily living functions in patients with schizophrenia.

METHODS

Sixty patients with schizophrenia were recruited. We used the Anticholinergic Drug Scale (ADS) for evaluating medication-associated anticholinergic burden. The MATRICS Consensus Cognitive Battery (MCCB) and the University of California San Diego Performance-based Skills Assessment (UPSA) were used for evaluating cognitive and daily living functions. To assess clinical symptoms, psychiatrists conducted interviews using the Positive and Negative Syndrome Scale and the Calgary Depression Scale for Schizophrenia.

RESULTS

Subjects were divided into low (n = 31) and high (n = 29) anticholinergic burden based on ADS scores of 3 or more. The "high ADS" group had poorer cognitive (composite MCCB score, p < 0.001) and daily living functions (total UPSA score, p = 0.001) than the "low ADS" group. Medication-associated anticholinergic burden was negatively correlated with cognitive functions (composite MCCB score, r = -0.512, p < 0.001) and daily living functions (total UPSA score, r = -0.355, p = 0.005). A regression analysis showed that anticholinergic burden significantly explained the decline in cognitive functions (composite MCCB score, R² = 0.262, p < 0.001) and daily living functions (total UPSA score, R² = 0.126, p = 0.005). Explanatory power was reduced after a covariate adjustment, but the effects of the composite MCCB score (p = 0.013) and of the transportation domain score of the UPSA (p = 0.048) remained significant.

CONCLUSIONS

Our analysis shows that anticholinergic burden reduces cognitive and daily living functions in patients with schizophrenia. A drug strategy with minimal anticholinergic burden may be helpful to patients if it does not adversely affect clinical symptoms.

Usefulness of the University of California San Diego Performance-Based Skills Assessment for the evaluation of cognitive function and activities of daily living function in patients with cognitive impairment

OBJECTIVES

To assess the usefulness of the University of California San Diego Performance-Based Skills Assessment (UPSA) as a new diagnostic method and tool for the assessment of cognitive function and activities of daily living function in patients with cognitive impairment.

METHOD

In total, 35 patients with cognitive impairment and 35 healthy controls were recruited for this study. The Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and Global Deterioration Scale (GDS) were used for the evaluation of cognitive function, while the Barthel Activities of Daily Living Index (BADL), Instrumental Activities of Daily Living Index (IADL), and UPSA were used for the evaluation of activities of daily living function.

RESULTS

UPSA scores were significantly lower in patients with cognitive impairment than in controls. The UPSA total score was significantly correlated with MMSE, CDR, GDS, and IADL scores. With regard to the detection of cognitive impairment, UPSA exhibited a greater determination power (R² = 0.593) compared with BADL (R² = 0.149) and IADL (R² = 0.423) and higher sensitivity and specificity compared with IADL.

CONCLUSION

Our results suggest that UPSA is a useful tool for the evaluation of cognitive function and activities of daily living function in patients with cognitive impairment.

Adjunct transcranial direct current stimulation improves cognitive function in patients with schizophrenia: A double-blind 12-week study

OBJECTIVES

Cognitive impairment is a common symptom of schizophrenia that has significant effects on quality of life and the activities of daily living. The present study examined the ability of transcranial direct current stimulation (tDCS) to improve cognitive function and clinical symptoms in patients with schizophrenia.

METHODS

Fifty-six patients with schizophrenia were randomized to real-tDCS and sham-tDCS groups. The participants were stable for a period of 3months before study enrollment. Each group received 30min of active 2-mA tDCS or sham stimulation over the left dorsolateral prefrontal cortex (anode F3, cathode F4) once per day for 10 consecutive weekdays. The Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) and Wisconsin Card Sorting Test (WCST) were used to evaluate cognitive function, and the Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression-Schizophrenia scale (CGI-SCH), and Calgary Depression Scale for Schizophrenia (CDSS) were used to evaluate symptoms at baseline, after 10 sessions, and at 3-month follow-up.

RESULTS

There was a significant time×group interaction, indicating that MCCB working memory (P=0.008) and overall scores (P=0.031) improved over time in the real-tDCS group compared to the sham-tDCS group. There was also a significant time×group interaction for depressive symptoms as evaluated by the CGI-SCH, which decreased over time in the real-tDCS group (P=0.041). tDCS treatment combined with antipsychotic medication was generally well-tolerated and safe.

CONCLUSIONS

Adjunct tDCS treatment is safe and effective for improving cognitive status in patients with schizophrenia.

Surgeon volume and prognosis of patients with advanced papillary thyroid cancer and lateral nodal metastasis

Background

Surgery is the most important treatment modality for papillary thyroid cancer (PTC). However, the relationship between surgeon volume and long-term oncological outcomes has not been explored.

Methods

Patients diagnosed with N1b PTC after initial thyroid surgery between 1 July 1994 and 31 December 2011 were eligible for inclusion in the study. Surgeons were categorized into high (at least 100 operations per year) and low (fewer than 100 operations per year) volume groups. Kaplan–Meier survival analysis according to surgeon volume was performed, and Cox proportional hazard modelling was used to estimate hazard ratios (HRs) with 95 per cent confidence intervals according to patient, tumour and surgeon factors.

Results

A total of 1103 patients with a median follow-up of 81 (i.q.r. 62–108) months were included in the study. During follow-up, 200 patients (18·1 per cent) developed structural recurrence. A high surgeon volume was associated with low structural recurrence (P = 0·006). After adjustment for age, sex and conventional risk factors for recurrence (histology, tumour size, gross extrathyroidal extension, margin status, more than 5 positive lymph nodes, radioactive iodine therapy), the adjusted HR for structural recurrence for low-volume surgeons was 1·46 (95 per cent c.i. 1·08 to 1·96), compared with high-volume surgeons. Distant metastasis (P = 0·242) and disease-specific mortality (P = 0·288) were not affected by surgeon volume.

Conclusion

Surgeon volume is associated with structural recurrence, but not distant metastasis or cancer-specific death in patients with N1b PTC. Surgeon volume is important in initial surgery for advanced PTC with extensive nodal metastasis in order to ensure curative outcome and reduce treatment-related morbidity.

Surgical Outcomes After Open, Laparoscopic, and Robotic Gastrectomy for Gastric Cancer

BACKGROUND

In contrast to the significant advantages of laparoscopic versus open gastrectomy, robotic gastrectomy has shown little benefit over laparoscopic gastrectomy. This study aimed to compare multi-dimensional aspects of surgical outcomes after open, laparoscopic, and robotic gastrectomy.

METHODS

Data from 915 gastric cancer patients who underwent gastrectomy by one surgeon between March 2009 and May 2015 were retrospectively reviewed. Perioperative parameters were analyzed for short-term outcomes. Surgical success was defined as the absence of conversion to open surgery, major complications, readmission, positive resection margin, or fewer than 16 retrieved lymph nodes.

RESULTS

This study investigated 241 patients undergoing open gastrectomy, 511 patients undergoing laparoscopic gastrectomy, and 173 patients undergoing robotic gastrectomy. For each approach, the respective incidences were as follows: conversion to open surgery (not applicable, 0.4%, and 0%; p = 0.444), in-hospital major complications (5.8, 2.7, and 1.2%; p = 0.020), delayed complications requiring readmission (2.9, 2.0, and 1.2%; p = 0.453), positive resection margin (1.7, 0, and 0%; p = 0.003), and inadequate number of retrieved lymph nodes (0.4, 4.1, and 1.7%; p = 0.010). Compared with open and laparoscopic surgery, robotic gastrectomy had the highest surgical success rate (90, 90.8, and 96.0%). Learning-curve analysis of success using cumulative sum plots showed success with the robotic approach from the start. Multivariate analyses identified age, sex, and gastrectomy extent as significant independent parameters affecting surgical success. Surgical approach was not a contributing factor.

CONCLUSIONS

Open, laparoscopic, and robotic gastrectomy exhibited different incidences and causes of surgical failure. Robotic gastrectomy produced the best surgical outcomes, although the approach method itself was not an independent factor for success.

Stimulating TRPV1 externalization and synthesis in dorsal root ganglion neurons contributes to PGE2 potentiation of TRPV1 activity and nociceptor sensitization

BACKGROUND

Persistent peripheral sensitization contributes to chronic pain. Plasticity of nociceptive dorsal root ganglion (DRG) neurons (nociceptors) induced by pro-inflammatory mediators contributes to sensitization. Prostaglandin E2 (PGE2) enriched in injured tissues is known not only directly to sensitize DRG neurons, but also to potentiate sensitizing effects of other pain mediators such as capsaicin and its receptor transient receptor potential vanilloid-1 (TRPV1). It remains unknown whether PGE2 potentiates TRPV1 activity by stimulating its synthesis, cell surface and axonal trafficking in DRG neurons.

METHODS

Combined biochemical, morphological, pharmacological and behavioral approaches have been used to address this issue in both in vitro and in vivo models.

RESULTS

PGE2 increased TRPV1 externalization in cultured rat DRG neurons in a time- and concentration-dependent manner, an event blocked by an inhibitor of protein synthesis or anterograde export. EP1 and EP4, but not EP2 and EP3, mediated this event. EP1 agonist-induced TRPV1 externalization was suppressed by inhibitors of CaMKII, PLC, PKC and PKCε, while EP4 agonist-induced TRPV1 externalization by inhibitors of cAMP/PKA and ERK/MAPK. Pre-exposure to PGE2 potentiated release of calcitonin gene-related peptide from cultured DRG neurons evoked by subsequent capsaicin stimulation. This event was blocked by an inhibitor of protein synthesis or export, suggesting that PGE2-induced TRPV1 synthesis and externalization is coupled to enhanced TRPV1 activity. Pre-exposure to PGE2 not only prolonged tactile allodynia evoked by subsequent capsaicin challenge, but also increased TRPV1 levels in L4-6 DRG, sciatic nerves and plantar skin.

CONCLUSIONS

Our data indicate that facilitating TRPV1 synthesis, cell surface and axonal trafficking is a novel mechanism underlying PGE2 potentiation of TRPV1 activity.

Clinical Significance of the Prognostic Nutritional Index for Predicting Short- and Long-Term Surgical Outcomes After Gastrectomy: A Retrospective Analysis of 7781 Gastric Cancer Patients

To evaluate the predictive and prognostic significance of the prognostic nutritional index (PNI) in a large cohort of gastric cancer patients who underwent gastrectomy.Assessing a patient's immune and nutritional status, PNI has been reported as a predictive marker for surgical outcomes in various types of cancer.We retrospectively reviewed data from a prospectively maintained database of 7781 gastric cancer patients who underwent gastrectomy from January 2001 to December 2010 at a single center. From this data, we analyzed clinicopathologic characteristics, PNI, and short- and long-term surgical outcomes for each patient. We used the PNI value for the 10th percentile (46.70) of the study cohort as a cut-off for dividing patients into low and high PNI groups.Regarding short-term outcomes, multivariate analysis showed a low PNI (odds ratio [OR] = 1.505, 95% CI = 1.212-1.869, P <0.001), old age, male sex, high body mass index, medical comorbidity, total gastrectomy, and combined resection to be independent predictors of postoperative complications. Among these, only low PNI (OR = 4.279, 95% CI = 1.760-10.404, P = 0.001) and medical comorbidity were independent predictors of postoperative mortality. For long-term outcomes, low PNI was a poor prognostic factor for overall survival, but not recurrence (overall survival: hazard ratio [HR] = 1.383, 95% CI = 1.221-1.568, P < 0.001; recurrence-free survival: HR = 1.142, 95% CI = 0.985-1.325, P = 0.078).PNI can be used to predict patients at increased risk of postoperative morbidity and mortality. Although PNI was an independent prognostic factor for overall survival, the index was not associated with cancer recurrence.

Synergistic integration of ion-exchange and catalytic reduction for complete decomposition of perchlorate in waste water

Ion-exchange has been frequently used for the treatment of perchlorate (ClO4(-)), but disposal or regeneration of the spent resins has been the major hurdle for field application. Here we demonstrate a synergistic integration of ion-exchange and catalytic decomposition by using Pd-supported ion-exchange resin as an adsorption/catalysis bifunctional material. The ion-exchange capability of the resin did not change after generation of the Pd clusters via mild ethanol reduction, and thus showed very high ion-exchange selectivity and capacity toward ClO4(-). After the resin was saturated with ClO4(-) in an adsorption mode, it was possible to fully decompose the adsorbed ClO4(-) into nontoxic Cl(-) by the catalytic function of the Pd catalysts under H2 atmosphere. It was demonstrated that prewetting the ion-exchange resin with ethanol significantly accelerate the decomposition of ClO4(-) due to the weaker association of ClO4(-) with the ion-exchange sites of the resin, which allows more facile access of ClO4(-) to the catalytically active Pd-resin interface. In the presence of ethanol, >90% of the adsorbed ClO4(-) could be decomposed within 24 h at 10 bar H2 and 373 K. The ClO4(-) adsorption-catalytic decomposition cycle could be repeated up to five times without loss of ClO4(-) adsorption capacity and selectivity.

P4-11-20: Observational Study of Body Weight Changes and Metabolic Syndrome in Breast Cancer Patients Receiving Adjuvant Therapy: Characteristics of Dietary Pattern in Korean Breast Cancer Patients

Backgroud: Obesity, postdiagnosis weight gain, and presence of metabolic syndrome in breast cancer are reported to adversely affect survival among breast cancer survivors. Most of the studies on weight gain and metabolic syndrome in breast cancer are from Western countries and few information is available on Asian population. We designed this prospective observational study to characterize weight and metabolic changes during adjuvant treatment in women with early breast cancer and to identify factors associated with occurrence of metabolic syndrome, focusing on dietary pattern.

Methods: Patients aged 18–75 who underwent curative surgery with stage I-III invasive breast cancer were enrolled from 2008 to 2010. We measured glucose (FBS), hemoglobin A1c (HbA1c), total cholesterol (TC), HDL cholesterol, and triglyceride (TG) level in fasting serum samples before starting adjuvant therapy, at 6 months and 12 months after enrollment. Body weight, body mass index (BMI), body fat mass, and percent body fat at baseline, 6 months, and 12 months were also measured. Dietary intake was assessed using valid semi-quantitative Food frequency questionnaire (FFQ).

Results: Total of 63 patients were enrolled. Median age of the enrolled patients were 48 (range, 25–68), with premenopausal/postmenopausal 40 (63.5%)/ 23 (36.5%). Fifty (82.0%) and 10 (16.4%) received adjuvant chemotherapy followed by hormone therapy and hormone therapy alone. Hormone receptor positive (ER+/PR+) and HER2 positive cancer accounted for 52 (83.9%) and 7 (12.1%). Mean FBS, HbA1c, TC, HDL, and TG level was 99.9 mg/dL (range, 83–159), 5.59 mg/dL (range, 4.8−7.5), 197.4 mg/dL (125-298), 51.9 mg/dL (range, 30–90), and 119.7 mg/dL (42-371). Mean height, weight, and BMI was 158 cm (range, 149–169), 61.7kg (range, 46.2−96.0), and 24.7 kg/m2 (range, 18.7−35.7), respectively. According to the WHO and NTH guidelines for Asian, normal (BMI 18.5−22.9), overweight (BMI 23–24.9), and obesity (BMI≥25) was 18 (28.6%), 13 (20.6%), and 32 (50.8%), respectively. Number of patients with metabolic syndrome was 18 (34%). Mean BMI (26.1 vs 24.0, p=0.021) and TG (180.6 vs 92.0, p&lt;0.001) was higher, HDL cholesterol was lower (42.2 vs 57.3, p&lt;0.001) in patients with metabolic syndrome. Composition of daily calorie intake consisted of 13.5% (range 10.7−21.8) of protein, 6.7% (range, 3.3−22.1) of fat, and 70.1% (range, 28.1−79.5) of carbohydrate. The presence of metabolic syndrome was associated with a higher carbohydrate intake (carbohydrate intake per ideal body weight&gt;6.0) (p=0.071). The TG level of patients who indigested high carbohydrate was significantly higher (143.8 vs 102.9, p=0.023). The HDL level of patients who took high fat diet (&gt;20% of total calorie) was lower (45.3 vs 53.5, p=0.045).

Conclusion: In our cohort of Korean breast cancer patients, 34% had metabolic syndrome at baseline. Those patients with metabolic syndrome consumed higher proportion of carbohydrate, which resulted in significantly higher level of TG. Our data suggest that composition of calorie intake is different in Asian population compared to Western countries, warranting for reappraisal on the recommendation on life style modification and diet.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-11-20.

Which oblique plane is more helpful in diagnosing an anterior cruciate ligament tear?

AIM

To evaluate the diagnostic role of additional oblique coronal and oblique sagittal magnetic resonance imaging (MRI) for an anterior cruciate ligament (ACL) tear.

MATERIALS AND METHODS

A total of 101 patients who had undergone preoperative knee MRI examinations with orthogonal and two sets of oblique images were enrolled in the study. Two radiologists evaluated the MRI images by the use of four methods: orthogonal images only (method A); orthogonal and additional oblique coronal images (method B); orthogonal and oblique sagittal images (method C); and orthogonal images with oblique coronal and sagittal images (method D). The status of the ACL (normal or tear) was determined by consensus. The sensitivity, specificity, and accuracy for an ACL tear with the use of each method were calculated in comparison with arthroscopy as the reference standard, and values were statistically analysed using the McNemar test. The diagnostic accuracies were compared using receiver operating characteristic (ROC) analysis.

RESULTS

Arthroscopy identified 10 partial ACL tears and 30 complete ACL tears. The specificities and accuracies for methods B, C, and D were significantly higher than the specificities and accuracies for method A (p<0.05). There was no significant difference in the sensitivity, specificity, and accuracy for methods B, C, and D. Diagnostic ability was not significantly different for each method, as determined by ROC analysis (p>0.05).

CONCLUSIONS

Additional oblique imaging for an ACL tear improved the specificity. Either of the oblique imaging methods is sufficient, and no further improvement in the diagnostic efficacy was achieved by simultaneous use.

Promoter methylation of p16, DAPK, CDH1, and TIMP-3 genes in cervical cancer: correlation with clinicopathologic characteristics

This study was conducted to investigate the promoter methylation status of the p16, DAPK, CDH1, and TIMP-3 genes in primary cervical cancer and its correlation with clinicopathologic characteristics. Promoter methylation was evaluated using a methylation-specific polymerase chain reaction in 78 cervical cancer tissue specimens and 24 control, normal cervical tissue specimens. Clinicopathologic parameters were obtained from medical records, and the relationship between the discrete variables and the methylation status was evaluated. The frequencies of promoter methylation of p16, DAPK, CDH1, and TIMP-3 in cervical cancer were 57%, 44.9%, 52.6%, and 9%, respectively. Primary cervical cancer had significantly higher methylation frequencies for the p16 and DAPK promoters than did the control, normal cervix (P < 0.0001). The promoter methylation of TIMP-3 was significantly higher in adenocarcinoma than in squamous cell carcinoma (41.7% vs 3%, respectively, P= 0.0175). High-stage cancers exhibited an increased promoter methylation frequency for p16 (P= 0.0061). The promoter methylation of the p16 gene is a frequent event in cervical carcinogenesis and may have potential clinical application as a marker for the progression and prognosis of cancer.

Purification, crystallization and preliminary X-ray analysis of truncated and mutant forms of VP4 protease from infectious pancreatic necrosis virus

In viruses belonging to the Birnaviridae family, virus protein 4 (VP4) is the viral protease responsible for the proteolytic maturation of the polyprotein encoding the major capsid proteins (VP2 and VP3). Infectious pancreatic necrosis virus (IPNV), the prototype of the aquabirnavirus genus, is the causative agent of a contagious disease in fish which has a large economic impact on aquaculture. IPNV VP4 is a 226-residue (24.0 kDa) serine protease that utilizes a Ser/Lys catalytic dyad mechanism (Ser633 and Lys674). Several truncated and mutant forms of VP4 were expressed in a recombinant expression system, purified and screened for crystallization. Two different crystal forms diffract beyond 2.4 A resolution. A triclinic crystal derived from one mutant construct has unit-cell parameters a = 41.7, b = 69.6, c = 191.6 A, alpha = 93.0, beta = 95.1, gamma = 97.7 degrees. A hexagonal crystal with space group P6(1)22/P6(5)22 derived from another mutant construct has unit-cell parameters a = 77.4, b = 77.4, c = 136.9 A.

A two-year longitudinal study of dental caries in permanent first molars of Korean elementary schoolchildren

OBJECTIVE

This longitudinal study investigated dental caries increment in permanent first molars of Korean elementary schoolchildren.

METHODS

A convenience sample of 722 children aged 7-9 years attending one urban elementary school was examined at baseline, with follow-up examinations at one and two years. Coronal surfaces of permanent first molars were scored with regard to caries experience and sealant status.

RESULTS

Among sound occlusal surfaces at baseline, 21 percent of upper and 25 percent of lower surfaces developed caries during the two-year interval. In teeth that erupted between baseline and the first follow-up exam, over 10 percent of occlusal surfaces developed caries. Pit and fissure caries accounted for 93 percent of all new carious surfaces, while sealants had been placed on 16 percent of occlusal surfaces during the study.

CONCLUSIONS

Recognizing the limitations of this convenience sample, dental sealants should be used more widely in this Korean population, and should be applied soon after tooth eruption.

Postprandial hypertriglyceridemia impairs endothelial function by enhanced oxidant stress

AIMS

it appears that hypertriglyceridemia (HTG) is a risk factor of atherosclerosis as demonstrated by recent studies. In this study, we analyzed the effects of acute HTG on endothelial function and oxidative stress, which are important mechanisms in the pathogenesis of atherosclerosis.

METHODS AND RESULTS

in a high fat meal group (n = 11), serum triglycerides and PMA-activated leukocyte O(2)(-)* production were significantly (P < 0.005) increased from 146 +/- 69 mg/dl and 4.09 +/- 0.93 nmol/10(6) cells/min preprandially to 198 +/- 88 mg/dl and 5.49 +/- 1.19 nmol/10(6) cells/min, respectively, 2 h after eating a high-fat meal. The flow-mediated endothelium-dependent brachial artery dilation (FMD; high-resolution ultrasound) was decreased from 13.7 +/- 3.3% preprandially to 8.2 +/- 3.7%, 2 h after eating a high-fat meal (P < 0.005). However, following a low-fat meal (n = 9), there were no significant changes in triglycerides, leukocyte O(2)(-)* production and FMD. Changes of serum triglycerides were correlated negatively (r = -0.650, P < 0.005) with changes of FMD, but were correlated positively (r = 0.798, P < 0.001) with changes of leukocyte O(2)(-)* production, which - in turn - were correlated negatively (r = -0.784, P < 0.001) with changes of FMD in all study subjects (mean age: 56 years, n = 20).

CONCLUSIONS

this study suggests that acute HTG causes endothelial dysfunction via enhanced oxidant stress and this may pave the way for the development of atherosclerosis under chronic conditions.

Estrogen modulation of prolactin gene expression requires an intact mitogen-activated protein kinase signal transduction pathway in cultured rat pituitary cells

Expression of the PRL gene is regulated by many factors, including cAMP, estradiol (E2), phorbol esters, epidermal growth factor (EGF), and TRH. The promoter region of the rat PRL gene has been shown to contain DNA sequences that are thought to support the direct interaction of estrogen receptors (ERs) with DNA. It is by this direct ER/DNA interaction that estrogen is thought to modulate expression of PRL. We report here that estrogeninduced PRL expression requires an intact mitogen-activated protein kinase (MAPK) signal transduction pathway in cultured rat pituitary cells (PR1 lactotroph and GH3 somatolactotroph cell lines). Interfering with the MAPK signaling cascade by inhibiting the activity of MAPK kinase (MEK) ablates the ability of estrogen to induce PRL mRNA and protein. In these cell lines, estrogen activates extracellular regulated protein kinases ERK-1 and ERK-2 enzyme activities maximally within 10 min of 1 nM E2 treatment. This activity is blocked by pretreatment of the cells with the MEK inhibitors PD98059 and UO126. The mechanism by which ERKs-1 and -2 are activated by estrogen appears to be independent of c-Src since the effects of estrogen on PRL gene expression are not affected by herbimycin A or PP1 administration. c-Raf-1 may be involved in the effects of E2 because estrogen causes the rapid and transient tyrosine phosphorylation of c-Raf-1. The ER antagonist ICI 182,780 blocks both ERK-1 and ERK-2 activation in addition to PRL protein and mRNA, implying a central role for the classical ER in the activation of the MAPK pathway resulting in PRL gene expression.

Pituitary apoplexy in a patient with acute myeloid leukemia and thrombocytopenia

We describe a 72-year-old woman with a history of acute myeloid leukemia who developed pituitary apoplexy associated with thrombocytopenia secondary to chemotherapy. She presented with new onset severe headache, nausea, vomiting and blurred vision. Initial physical examination was unremarkable. CT scan of the head was initially negative. Upon admission for further work up, She developed a high-grade fever, hypotension and obtundation. Subsequent physical examination revealed bitemporal visual fields defects and decreased visual acuity. Repeat imaging of head revealed a hemorrhagic pituitary mass compressing the optic chiasm. Laboratory results were compatible with the diagnosis of pan-hypopituitary syndrome. She received high dose steroids and was transferred for transnasal sphenoidotomy decompression surgery. The visual defects improved postoperatively. A literature review of Pituitary apoplexy is presented. Pituitary apoplexy secondary to thrombocytopenia has never been reported.

Epidermal growth factor-stimulated tyrosine phosphorylation of caveolin-1. Enhanced caveolin-1 tyrosine phosphorylation following aberrant epidermal growth factor receptor status

Caveolin-1 is the major coat protein of caveolae and has been reported to interact with various intracellular signaling molecules including the epidermal growth factor (EGF) receptor. To investigate the involvement of caveolin-1 in EGF receptor action, we used mouse B82L fibroblasts transfected with (a) wild type EGF receptor, (b) a C-terminally truncated EGF receptor at residue 1022, (c) a C-terminally truncated EGF receptor at residue 973, or (d) a kinase-inactive EGF receptor (K721M). Following EGF treatment, there was a distinct electrophoretic mobility shift of the caveolin-1 present in cells expressing the truncated forms of the EGF receptor, but this shift was not detectable in cells bearing either normal levels of the wild type EGF receptor or a kinase-inactive receptor. This mobility shift was also not observed following the addition of other cell stimuli, such as platelet-derived growth factor, insulin, basic fibroblast growth factor, or phorbol 12-myristate 13-acetate. Analysis of caveolin-1 immunoprecipitates from EGF-stimulated or nonstimulated cells demonstrated that the EGF-induced mobility shift of caveolin-1 was associated with its tyrosine phosphorylation in cells expressing truncated EGF receptors. Maximal caveolin-1 phosphorylation was achieved within 5 min after exposure to 10 nM EGF and remained elevated for at least 2 h. Additionally, several distinct phosphotyrosine-containing proteins (60, 45, 29, 24, and 20 kDa) were co-immunoprecipitated with caveolin-1 in an EGF-dependent manner. Furthermore, the Src family kinase inhibitor, PP1, does not affect autophosphorylation of the receptor, but it does inhibit the EGF-induced mobility shift and phosphorylation of caveolin-1. Conversely, the MEK inhibitors PD98059 and UO126 could attenuate EGF-induced mitogen-activated protein kinase activation, they do not affect the EGF-induced mobility shift of caveolin-1. Because truncation and overexpression of the EGF receptor have been linked to cell transformation, these results provide the first evidence that the tyrosine phosphorylation of caveolin-1 occurs via an EGF-sensitive signaling pathway that can be potentiated by an aberrant activity or expression of various forms of the EGF receptor.

Platelet-derived growth factor-stimulated migration of murine fibroblasts is associated with epidermal growth factor receptor expression and tyrosine phosphorylation

Previous studies have shown that epidermal growth factor (EGF) synergizes with various extracellular matrix components in promoting the migration of B82L fibroblasts expressing wild-type EGF receptors and that functional EGF receptors are critical for the conversion of B82L fibroblasts to a migratory cell type (). In the present study, we examined the effects of platelet-derived growth factor (PDGF) on the motility of B82L fibroblasts using a microchemotaxis chamber. We found that PDGF can enhance fibronectin-induced migration of B82L fibroblasts expressing wild-type EGF receptors (B82L-clone B3). However, B82L cells that lack the EGF receptor (B82L-parental) or that express an EGF receptor that is kinase-inactive (B82L-K721M) or C-terminally truncated (B82L-c'973) exhibit little PDGF-stimulated migration. In addition, none of these three cell lines exhibit the capacity to migrate to fibronectin alone. These observations indicate that, similar to cell migration toward fibronectin, PDGF-induced cell migration of B82L fibroblasts is augmented by the expression of an intact EGF receptor kinase. The loss of PDGF-stimulated motility in B82L cells that do not express an intact EGF receptor does not appear to result from a gross dysfunction of PDGF receptors, because ligand-stimulated tyrosine phosphorylation of the PDGF-beta receptor and the activation of mitogen-activated protein kinases are readily detectable in these cells. Moreover, an interaction between EGF and PDGF receptor systems is supported by the observation that the EGF receptor exhibits an increase in phosphotyrosine content in a time-dependent fashion upon the addition of PDGF. Altogether, these studies demonstrate that the expression of EGF receptor is critical for PDGF-stimulated migration of murine B82L fibroblasts and suggest a role for the EGF receptor downstream of PDGF receptor activation in the signaling events that lead to PDGF-stimulated cell motility.

A case of aortocoronary dissection as a complication during a percutaneous transluminal coronary angioplasty (PTCA)

We report a case of aortocoronary dissection during a percutaneous transluminal coronary angioplasty (PTCA) which resulted from an antegrade and also a progressively retrograde extension of the coronary dissection into the Sinus of Valsalva and the ascending aorta. It was successfully treated with stenting without an operation, resulting in optimal coronary blood flow and diminution of the aortic dissection.

Effect of prenatal ethanol exposure on the developmental profile of the NMDA receptor subunits in rat forebrain and hippocampus

The effects of prenatal ethanol exposure on the NMDAR1 protein expression (postnatal days 1 and 7) and on the developmental profile of the NMDAR2A and NMDAR2B subunits in rat forebrain and hippocampus were investigated. Forebrain and hippocampal membrane proteins were isolated from pups of various ages (postnatal days 1 to 21) from prenatally ethanol exposed, pair-fed and ad libitum control groups. A semiquantitative immunoblot procedure was used with antibodies raised against the NMDAR1, NMDAR2A, and the NMDAR2B subunits to assess the NMDA subunit protein expression in the samples. NMDAR1 protein expression was unaffected by prenatal ethanol exposure at postnatal day 1 or 7 in both the forebrain and hippocampus. NMDAR2A protein expression levels rose rapidly in both forebrain and hippocampus during the time frame of study. Prenatal ethanol exposure caused a significant reduction in protein expression levels of the NMDAR2A in forebrain through postnatal day 14. NMDAR2B protein expression levels were high throughout the study in both forebrain and hippocampus. Prenatal ethanol exposure significantly reduced protein expression of the NMDAR2B in the forebrain (through postnatal day 14) and hippocampus (up to day 7). The results suggest that there may be a link between the depressed expression of the NMDAR2 subunits and the neurodevelopmental disorders associated with fetal ethanol exposure.

Coronavirus transcription mediated by sequences flanking the transcription consensus sequence

In our studies of murine coronavirus transcription, we continue to use defective interfering (DI) RNAs of mouse hepatitis virus (MHV) in which we insert a transcription consensus sequence in order to mimic subgenomic RNA synthesis from the nondefective genome. Using our subgenomic DI system, we have studied the effects of sequences flanking the MHV transcription consensus sequence on subgenomic RNA transcription. We obtained the following results. (i) Insertion of a 12-nucleotide-long sequence including the UCUAAAC transcription consensus sequence at different locations of the DI RNA resulted in different efficiencies of subgenomic DI RNA synthesis. (ii) Differences in the amount of subgenomic DI RNA were defined by the sequences that flanked the 12-nucleotide-long sequence and were not affected by the location of the 12-nucleotide-long sequence on the DI RNA. (iii) Naturally occurring flanking sequences of intergenic sequences at gene 6-7, but not at genes 1-2 and 2-3, contained a transcription suppressive element(s). (iv) Each of three naturally occurring flanking sequences of an MHV genomic cryptic transcription consensus sequence from MHV gene 1 also contained a transcription suppressive element(s). These data showed that sequences flanking the transcription consensus sequence affected MHV transcription.

Characterization of a murine coronavirus defective interfering RNA internal cis-acting replication signal

The mouse hepatitis virus (MHV) sequences required for replication of the JHM strain of MHV defective interfering (DI) RNA consist of three discontinuous genomic regions: about 0.47 kb from both terminal sequences and a 0.13-kb internal region present at about 0.9 kb from the 5' end of the DI genome. In this study, we investigated the role of the internal 0.13-kb region in MHV RNA replication. Overall sequences of the 0.13-kb regions from various MHV strains were similar to each other, with nucleotide substitutions in some strains; MHV-A59 was exceptional, with three nucleotide deletions. Computer-based secondary-structure analysis of the 0.13-kb region in the positive strand revealed that most of the MHV strains formed the same or a similar main stem-loop structure, whereas only MHV-A59 formed a smaller main stem-loop structure. The RNA secondary structures in the negative strands were much less uniform among the MHV strains. A series of DI RNAs that contained MHV-JHM-derived 5'- and 3'-terminal sequences plus internal 0.13-kb regions derived from various MHV strains were constructed. Most of these DI RNAs replicated in MHV-infected cells, except that MRP-A59, with a 0.13-kb region derived from MHV-A59, failed to replicate. Interestingly, replication of MRP-A59 was temperature dependent; it occurred at 39.5 degrees C but not at 37 or 35 degrees C, whereas a DI RNA with an MHV-JHM-derived 0.13-kb region replicated at all three temperatures. At 37 degrees C, synthesis of MRP-A59 negative-strand RNA was detected in MHV-infected and MRP-A59 RNA-transfected cells. Another DI RNA with the internal 0.13-kb region deleted also synthesized negative-strand RNA in MHV-infected cells. MRP-A59-transfected cells were shifted from 39.5 to 37 degrees C at 5.5 h postinfection, a time when most MHV negative-strand RNAs have already accumulated; after the shift, MRP-A59 positive-strand RNA synthesis ceased. The minimum sequence required for maintenance of the positive-strand major stem-loop structure and biological function of the MHV-JHM 0.13-kb region was about 57 nucleotides. Function was lost in the 50-nucleotide sequence that formed a positive-strand stem-loop structure identical to that of MHV-A59. These studies suggested that the RNA structure made by the internal sequence was important for positive-strand MHV RNA synthesis.

Analysis of cis-acting sequences essential for coronavirus defective interfering RNA replication

Mouse hepatitis virus (MHV) defective interfering (DI) RNA was used to determine the cis-acting sequences required for MHV RNA replication. A 2.2-kb-long cDNA clone of the MHV DI RNA DIssE was used to test the effect of deletions throughout the DI RNA on replication in DI RNA-transfected, MHV-infected cells. Data from a series of deletion mutants demonstrated that about 470 nucleotides at the 5' terminus, 460 nucleotides at the 3' terminus, and about 135 nucleotides in an internal position approximately 0.9 kb from the 5' end of DI RNA were necessary for DI RNA replication. These data suggested that cis-acting sequences which were necessary for MHV RNA replication required not only terminal sequences but also an internal sequence present at about 3.2 kb from the 5' end of the genome.

Modulation of doxorubicin efficacy in P388 leukemia following co-administration of verapamil in mini-osmotic pumps

Co-administration of doxorubicin and verapamil in Alzet mini-osmotic pumps increased the survival of B6D2F1 mice bearing the multidrug-resistant P388/ADR leukemia. A range of doxorubicin and verapamil combinations was studied to define dose-dependent efficacy and toxicity. High doses of doxorubicin (10 mg/kg/day) and verapamil (150 mg/kg/day) could be administered alone without any effect on survival. However, combining high doses of these two agents resulted in host toxicity. Doxorubicin doses of 1 to 10 mg/kg/day in combination with verapamil at 25-100 mg/kg/day were found to improve survival compared with either agent alone. Combination therapy also improved the survival of mice bearing the drug-sensitive P388/0 leukemia when compared to anthracycline treatment alone. The efficacy of the mini-osmotic pump delivery protocol was compared with other regimens delivering the same total cumulative dose of doxorubicin via repeated i.p. injections.

Generation and selection of coronavirus defective interfering RNA with large open reading frame by RNA recombination and possible editing

All of the coronavirus defective interfering (DI) RNAs analyzed thus far contain an open reading frame (ORF) from which DI RNA-specific protein(s) are translated, although the function of the DI-specific protein and the significance of the ORF are not known. A complete cDNA clone of a mouse hepatitis virus (MHV) DI RNA, NE-1, containing a single nucleotide deletion in the 5' region of the ORF was obtained and analyzed. Due to this single nucleotide deletion, a DI-specific protein of 7.5-kDa was made from NE-1, in contrast to the 88-kDa protein made from the wild-type DI RNA. NE-1 RNA was efficiently replicated after transfection into MHV-infected cells. However, after one passage of NE-1 RNA-containing virus, the 88-kDa wild-type protein was synthesized, indicating that the large ORF was restored during NE-1 DI RNA replication. Sequence analysis of NE-1 DI RNA from infected cells demonstrated that in approximately half of the DI RNA population, the ORF was restored by RNA recombination between NE-1 DI RNA and helper virus genomic sequence. The sequences of other DI RNAs contained an additional nontemplated A at the five-A sequence nine nucleotides upstream of the deletion site, resulting in a stretch of six consecutive As. In these "edited"-type DI RNAs, the original nucleotide deletion was maintained and no RNA recombination was observed. This "editing" produced an ORF of the same size as the wild-type DI RNA. We conclude that the DI RNA with a large ORF has a selective advantage. There was no significant difference in replication efficiency among these RNAs when they replicated alone. However, cotransfection of two DI RNA species and time course experiments suggested that homologous interference and other mechanism(s) during the early stage of virus multiplication are responsible for the accumulation of DI RNAs containing the large ORF.

Enhancement of the attachment on microcarriers and tPA production by fibroblast cells in a serum-free medium by the addition of the extracts of Centella asiatica

The addition of ethanol extracts of Centella asiatica showed a remarkable enhancement of fibroblast cells attachment to Cytodex beads in serum-free (SF) medium. It also improves tPA production in both batch and perfusion cultivations. The optimal concentration for SF medium was determined as 2 ppm of the extracts when using Cytodex III. In batch cultivation a high specific tPA production rate was obtained, compared to that from 5% FBS containing medium. However, a fast specific growth rate was observed in 5% FBS medium. In perfusion cultivation a reasonably good cell density and tPA production was achieved at a perfusion rate of 2.4 x 10(6) (viable cell/ml) and 0.65 (micrograms/ml), respectively at 22 ml/min.

Recurrence of conduction in accessory atrioventricular connections after initially successful radiofrequency catheter ablation

The purpose of this study was to characterize the incidence and clinical features of accessory pathway recurrence after initially successful radiofrequency catheter ablation and to identify variables correlated with recurrence. Radiofrequency ablation was performed with a 7F deflectable tip catheter with a large (4 mm in length) distal electrode. Left-sided accessory pathways were approached through the left ventricle and right-sided pathways by way of the right atrium. Patients were included in the study if 1) they had an initially successful procedure, defined as the absence of accessory pathway conduction immediately after ablation, and 2) had undergone a 3-month follow-up electrophysiologic test or had documented recurrence of accessory pathway conduction. Accessory pathway conduction recurred after initially successful ablation in 16 (12%) of 130 patients. Almost half (7 of 16) of these recurrences were in the 1st 12 h after ablation, and the last occurred after 106 days. Return of delta waves on the electrocardiogram (ECG) or spontaneous paroxysmal supraventricular tachycardia was the initial indication of recurrence in 15 of the 16 patients. Two patients with manifest accessory pathways exhibited recurrence with exclusively concealed accessory pathway conduction. Accessory pathways ablated from the tricuspid anulus (right free wall or septal accessory pathways) had a much higher recurrence rate (24%) than did those on the mitral anulus (6%). Fourteen of 15 patients have had successful repeat accessory pathway ablation after the initial recurrence. After a mean follow-up period of 4 +/- 3 months, there have been no repeat recurrences of any of these accessory pathways. It is concluded that accessory pathway recurrence is infrequent after successful radiofrequency catheter ablation.(ABSTRACT TRUNCATED AT 250 WORDS)

Conversion of typical to "atypical" atrioventricular nodal reentrant tachycardia after radiofrequency catheter modification of the atrioventricular junction

Typical atrioventricular (AV) nodal reentry tachycardia (AVNRT) is characterized by anterograde activation over a slowly conducting pathway and by retrograde activation through a rapidly conducting pathway. Preliminary reports suggest that radiofrequency catheter modification can eliminate typical AVNRT while preserving anterograde conduction. Radiofrequency catheter modification was used to treat 88 patients with typical AVNRT. After baseline electrophysiologic evaluation, the ablation catheter was positioned proximal and superior to the site of maximal His deflection. Radiofrequency energy was applied until there was significant attenuation of retrograde conduction, and elimination of AVNRT inducibility. Eighty-one patients were successfully treated and form the basis of this report. A new paroxysmal supraventricular tachycardia with RP greater than PR interval was induced at electrophysiologic testing after successful ablation in 9 patients (11%). Mean atrial-His activation time was 140 +/- 31 ms, and the ventriculoatrial activation time was 170 +/- 46 ms. This arrhythmia was induced only with ventricular pacing during isoproterenol infusion and appeared to be mediated by AV nodal reentry. New retrograde dual AV nodal physiology after modification was more frequent in patients with atypical tachycardia than in those without (4 of 9 vs 2 of 72; p less than 0.0001). Although none of the patients were treated, only 1 of 9 had an episode of spontaneous atypical tachycardia during a mean follow-up of 12 months. Results of this study confirm that typical AVNRT can be rendered noninducible without the complete destruction of reentrant pathways. Because induction of "atypical" AVNRT was not predictive of spontaneous arrhythmia recurrence, it should not be an indication for additional ablation sessions or long-term drug therapy.

Electrogram criteria for identification of appropriate target sites for radiofrequency catheter ablation of accessory atrioventricular connections

BACKGROUND

Catheter ablation of accessory atrioventricular (AV) connections using radiofrequency current has been demonstrated to be effective in the majority of patients with the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardia involving a concealed accessory AV connection. However, electrogram criteria have not been established to guide attempts at radiofrequency catheter ablation.

METHODS AND RESULTS

The characteristics of local electrograms recorded at successful and unsuccessful sites of radiofrequency catheter ablation were determined in 132 patients. Electrograms recorded at a total of 438 sites were analyzed: 338 recorded during ablation of 90 manifest accessory AV connections and 100 recorded during ablation of 44 concealed accessory AV connections. During ablation of manifest accessory AV connections, the independent predictors of outcome were electrogram stability (p less than 0.001), the interval between activation of the ventricular electrogram and onset of the QRS complex (p less than 0.001), and the presence of an accessory AV connection potential (p less than 0.001). Radiofrequency energy delivery at sites demonstrating stable electrograms, a probable or possible accessory AV connection potential, and activation of the local ventrical electrogram before the onset of the QRS complex had a 57% probability of success compared with a 3% probability of success at sites without these features. During ablation of concealed accessory AV connections, the independent predictors of outcome were electrogram stability (p = 0.02), the presence of an accessory AV connection potential (p = 0.05), and the presence of retrograde continuous electrical activity (p = 0.04). Sites demonstrating a stable local electrogram, an accessory AV connection potential, and retrograde continuous electrical activity had an 82% probability of success compared with only a 5% probability of success at sites demonstrating none of these features.

CONCLUSIONS

The local electrogram parameters of greatest importance in predicting the success or failure of radiofrequency catheter ablation of accessory AV connections are electrogram stability, the presence of an accessory AV connection potential, and the timing of ventricular activation relative to the QRS complex (for manifest accessory AV connections) or retrograde continuous electrical activity (for concealed accessory AV connections). Awareness of these variables during attempts at radiofrequency catheter ablation of accessory AV connections may minimize the number of unnecessary applications of radiofrequency energy.

Impedance Monitoring During Radiofrequency Catheter Ablation in Humans

Radiofrequency catheter ablation of accessory pathways and the atrioventricular junction often requires multiple applications of energy. The inability to determine the effects of any given application on the underlying tissue may contribute to this problem. In the present study, impedance was monitored in 20 patients undergoing radiofrequency catheter ablation, and the relationship between an initial decrease in impedance and subsequent effects were examined. An initial fall in impedance of more than 10 omega was 78% sensitive and 88% specific for predicting subsequent evidence of tissue heating (interruption of conduction or an abrupt rise in impedance due to coagulum formation). In contrast, initial values of voltage, current, or impedance did not distinguish between effective and ineffective applications of radiofrequency energy. Continuous monitoring of impedance may facilitate radiofrequency catheter ablation.

Acute myocardial infarction in a patient with Buerger's disease. A case report and a review of the literature

A twenty-nine year old male smoker with a three year history of Buerger’s disease was admitted with excruciating precordial chest pain. The electrocardiogram indicated an anterior transmural infarction, and he also exhibited hypereosinophilia.

A coronary angiogram disclosed a partial segmental occlusion of the left anterior descending artery at the proximal portion. He was discharged without any complications after conservative managment.

Micellar liquid chromatography for the analysis of nucleosides and bases

A new high-performance liquid chromatographic method for the analysis of nucleosides and bases was developed in which a micellar mobile phase is used. Separation was achieved on a polyvinyl alcohol (PVA) column by isocratic elution with micellar sodium dodecyl sulfate (SDS) as the mobile phase. The retention behavior of the nucleosides and bases was significantly different from that obtained by reversed-phase chromatography. Effect of pH, temperature, and concentration of SDS and the counter ion (Na+) on retention behavior were investigated. With the PVA column, the best conditions for an isocratic separation were 0.01 M SDS (pH 3.4) and a flow-rate of 2 ml/min at ambient temperature. Mechanisms for the retention of the nucleosides and bases on the PVA column with a micellar mobile phase were proposed and an application of the separation was demonstrated by the analysis of human serum.

The pressor response to angiotensin II in patients with low renin essential hypertension

The etiology of low renin essential hypertension (LREH) has not been established with certainty, but mineralocorticoid excess has been implicated frequently in its pathogenesis. The finding of several investigators of a normal exchangeable sodium space and extracellular fluid volume, however, does not support this hypothesis. To evaluate the possible role of sodium and water retention in LREH, the pressor response to infused angiotensin II (A II) was determined and compared to that of normal subjects and that of subjects with normal renin essential hypertension (NREH). This approach was based on the known suprasensitivity of vascular receptors to A II in situations in which sodium and water compartments are expanded as they are, for example, in proven hypermineralocorticoid states such as primary aldosteronism. In this study, we found that subjects with LREH demonstrated no increased pressor response to graded doses of A II; this suggests that LREH is not primarily mediated by sodium and water retention.