Dyspnea and palpitation during pregnancy

OBJECTIVES

Dyspnea and palpitation are common features of pregnancy. While several theories have been put forward to explain the etiology of gestational dyspnea and palpitation, there have been few systemic studies of its incidence, severity and time-course in a group of normal women.

METHODS

We interviewed postpartum women, within 3 days after delivery, about dyspnea and palpitation. Separately from this interview, we performed 24-hour ECG monitoring for obstetric patients with palpitation before delivery.

RESULTS

The subjects interviewed were 261 women, of whom 37.5 percent and 11.5 percent experienced dyspnea and palpitation, respectively. These symptoms had tendency to increase to term. The presence of arrhythmias could be documented in only 22% of patients having 24-hour Holter monitoring.

CONCLUSION

Dyspnea and palpitation were common among normal pregnant women and had a tendency to increase to term.

Antiplatelet activity of green tea catechins is mediated by inhibition of cytoplasmic calcium increase

We have previously reported that green tea catechins (GTC) display a potent antithrombotic activity, which might be due to antiplatelet rather than anticoagulation effects. In the current study, we investigated the antiplatelet mechanism of GTC. We tested the effects of GTC on the aggregation of human platelets and on the binding of fluorescein isothiocyanate-conjugated fibrinogen to human platelet glycoprotein (GP) IIb/IIIa. GTC inhibited the collagen-, thrombin-, adenosine diphosphate (ADP)-, and calcium ionophore A23187-induced aggregation of washed human platelets, with 50% inhibitory concentration values of 0.64, 0.52, 0.63, and 0.45 mg/ml, respectively. GTC significantly inhibited fibrinogen binding to human platelet surface GPIIb/IIIa complex but failed to inhibit binding to purified GPIIb/IIIa complex. These results indicate that the antiplatelet activity of GTC may be due to inhibition of an intracellular pathway preceding GPIIb/IIIa complex exposure. We also investigated the effects of GTC on intracellular calcium levels, which are critical in determining the activation status of platelets and on induction of platelet aggregation by thapsigargin, which is a selective inhibitor of the Ca(2+)-ATPase pump. Pretreatment of human platelets with GTC significantly inhibited the rise in intracellular Ca(2+) concentration induced by thrombin treatment, and GTC significantly inhibited the thapsigargin-induced platelet aggregation. We also examined the effect of GTC on the second messenger, inositol 1,4,5-triphosphate (IP(3)). GTC significantly inhibited the phosphoinositide breakdown induced by thrombin. Taken together, these observations suggest that the antiplatelet activity of GTC is be mediated by inhibition of cytoplasmic calcium increase, which leads to the inhibition of fibrinogen-GPIIb/IIIa binding via the activation of Ca(2+)-ATPase and inhibition of IP(3) formation.

Analysis of physicochemical factors related to the automatic pellicle removal in Korean chestnut (Castanea crenata)

Analyses were carried out for condensed tannin content, soluble sugar content, color, firmness, and peeling ratio of the pellicle of 14 varieties of Korean chestnut. The correlation between these physicochemical components and the peeling ratio was measured. The total soluble sugar content ranged from 4.20 to 11.83%. Condensed tannin contents in the inner and outer chestnut shells were 7.83-71.42% and 0.31-2.04%, respectively. In the outer shell of chestnut, CIE L* value was 26.98-33.34, CIE a value was 7.56-14.90, and CIE b value was 7.36-15.67. Firmness of chestnut was 4.41-9.20 kg. Peeling ratio of the pellicle by the peeling machine was significantly different with variety. The average peeling ratio was 63.79%, and that of the Okkwang variety was the highest at 85.29%. A negative correlation was found between tannin content of inner shell and peeling ratio (r = -0.57), but the correlation coefficients between other components and the peeling ratio were not significant.

Traumatic posterior atlantooccipital dislocation with Jefferson fracture and fracture-dislocation of C6-C7: a case report with survival

Atlantooccipital dislocation (AOD) is a rare and usually fatal injury. In the current study, the authors reported an extremely rare case of posterior AOD with Jefferson fracture and fracture-dislocation of C6-C7. The patient survived the injury and had only incomplete quadriplegia below the C7 segment with anterior cord syndrome. He was successfully managed with in situ occipitocervical fusion using the Cotrel-Dubousset rod system, corpectomy of C6, and anterior interbody fusion of C5-C7 with plating. To our knowledge, this is the first report of posterior AOD with two other non-contiguous cervical spine injuries. A high index of suspicion and careful examination of the upper cervical spine should be considered as the key to the diagnosis of AOD in cases that involve multiple or lower cervical spine injuries.

Simple bone cyst of lamina of lumbar spine: a case report

STUDY DESIGN

A case report and literature review.

OBJECTIVE

To describe an extremely rare simple bone cyst involving the lamina of the lumbar spine.

SUMMARY OF BACKGROUND DATA

Simple bone cysts involving the spine are very rare. Moreover, the authors are unaware of any published report of a simple bone cyst involving the lamina of the spine.

METHODS

A cystic lesion, incidentally identified in a patient with lumbar disc herniation of L5-S1, located at the left lamina of L5, was surgically treated with complete resection of the involved lamina and discectomy of L5-S1. Medical records, imaging studies, histologic findings, and related literature are reviewed in this study.

RESULTS

Histologic examination of a section of the cystic lesion showed a thin fibrous lining membrane of the cyst surrounded by well-vascularized new bone formation. This result is consistent with the findings of previously reported simple bone cysts in other sites of the body, including the spine.

CONCLUSION

This study suggests that a simple bone cyst may be included in the differential diagnosis of a cystic lesion of the posterior elements, especially laminae, of the spine.

Isoform-specific changes of adenylate cyclase mRNA expression in rat brains following chronic electroconvulsive shock

1. Electroconvulsive shock (ECS) has been reported to regulate the cAMP signaling system at various levels, suggesting that the cAMP system is involved in the therapeutic mechanism. 2. Chronic ECS has been suggested to change the expressions of adenylate cyclase (AC) genes, which constitute at least 9 families. However, little is known about its effect on the expression of AC. Therefore, to understand how chronic ECS alters the expression of AC genes in the brain, the authors analyzed the expression of 9 AC isoforms at the transcriptional level in rat hippocampus and cerebellum by quantitative RT-PCR following chronic ECS treatment. 3. Chronic ECS treatment was found to induce differential changes in the expression of AC isoforms in an isoform- and brain region-specific manner in the rat hippocampus and cerebellum. 4. Thus, it is concluded that chronic ECS induces differential changes in the expression of AC isoform mRNA in an isoform- and brain region-specific manner in the rat hippocampus and cerebellum. This suggests that the differential expression of AC isoforms might be an important mechanism by which chronic ECS treatment regulates the cAMP signaling system in rat brains.

Quantitative analysis of transforming growth factor-beta 1 in ligamentum flavum of lumbar spinal stenosis and disc herniation

STUDY DESIGN

The concentration of transforming growth factor-beta 1 (TGF-beta1) was examined in the ligamentum flavum of lumbar spinal stenosis and disc herniation.

OBJECTIVE

To investigate the role of TGF-beta1 on hypertrophy of the ligamentum flavum in lumbar spinal stenosis compared with that of lumbar disc herniation.

SUMMARY OF BACKGROUND DATA

The hypertrophy of the ligamentum flavum is known to be related to degenerative changes that are secondary to the aging process or mechanical instability. However, there has been no study to investigate the effect of biochemical factors, such as growth factors, associated with hypertrophy of the ligamentum flavum.

METHODS

The concentrations of TGF-beta1 were analyzed in the surgically obtained ligamentum flavum specimens from lumbar spinal stenosis (n = 10; mean age 62.8 years) and disc herniation (n = 10; mean age 35.6 years) by enzyme-linked immunosorbent assay. The localization of TGF-beta1 within the ligamentum flavum was determined using immunohistochemical study. The thickness of the ligamentum flavum was measured with axial T1-weighted magnetic resonance imaging. The biochemical and radiologic results were compared for these two conditions.

RESULTS

The mean concentration of TGF-beta1 was 123.78 pg/100 microg protein (range 11-374 pg/100 microg protein) in lumbar spinal stenosis and 38.56 pg/100 microg protein (range 0-155 pg/100 microg protein) in lumbar disc herniation; the difference between lumbar spinal stenosis and disc herniation was statistically significant (P = 0.029). The mean thickness of the ligamentum flavum was 4.44 mm (range 3.4-5.4 mm) in lumbar spinal stenosis and 2.44 mm (range 1.8-4.0 mm) in lumbar disc herniation; the difference between lumbar spinal stenosis and disc herniation was statistically significant (P = 0.001). On immunohistochemical study TGF-beta1 was positively stained on the fibroblasts within the ligamentum flavum specimens.

CONCLUSION

The current results suggest that higher expression of TGF-beta1 by fibroblasts might be related to the development of hypertrophy of the ligamentum flavum in lumbar spinal stenosis.

Electroconvulsive shock reduces inositol trisphosphate receptor1 mRNA in rat brain

We studied the expression pattern of the inositol 1,4,5-trisphosphate receptor1 (InsP3R1) mRNA after a single electroconvulsive shock (ECS) in the rat brain by in situ hybridization. The expression was significantly decreased in the dentate gyrus and the CA1 area of the hippocampal formation 3 to 24 h after ECS. While the downregulation of InsP3R1 by accelerated protein degradation has been reported, our results indicate that the downregulation of InsP3R1 occurs at the mRNA level. This finding, along with our previous report on the InsP3 3-kinase(A), suggests that ECS regulates the phosphoinositide mediated signaling, which might be related to the therapeutic mechanism of ECS.

Antioxidant effects of vitamins C and E are associated with altered activation of vascular NADPH oxidase and superoxide dismutase in stroke-prone SHR

Ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) have antioxidant properties that could improve redox-sensitive vascular changes associated with hypertension. We determined whether vitamins C and E influence vascular function and structure in hypertension by modulating activity of NADPH oxidase and superoxide dismutase (SOD). Adult stroke-prone spontaneously hypertensive rats (SHRSP) were divided into 3 groups: control (C; n=6), vitamin C-treated (vit C, 1000 mg/day; n=7), and vitamin E-treated (vit E, 1000 IU/day; n=8). All rats were fed 4% NaCl. Blood pressure was measured weekly. After 6 weeks of treatment, the rats were killed, and mesenteric arteries were mounted as pressurized preparations. Vascular O(2)(-) generation and NADPH oxidase activity were measured by chemiluminescence. Vascular SOD activity and plasma total antioxidant status (TAS) were determined spectrophotometrically. Blood pressure increased from 212+/-7 to 265+/-6 mm Hg in controls. Treatment prevented progression of hypertension (vit C, 222+/-6 to 234+/-14 mm Hg; vit E, 220+/-9 to 227+/-10 mm Hg). Acetylcholine-induced vasodilation was improved (P<0.05), and media-to-lumen ratio was reduced (P<0.05) in the treated rats. O(2)(-) was lower in vitamin-treated groups compared with controls (vit C, 10+/-4 nmol. min(-1). g(-1) dry tissue weight; vit E, 9.6+/-3.5 nmol. min(-1). g(-1) dry tissue weight; C, 21+/-9 nmol. min(-1). g(-1) dry tissue weight; P<0.05). Both vitamin-treated groups showed significant improvement (P<0.01) in TAS. These effects were associated with decreased activation of vascular NADPH oxidase (vit C, 46+/-10; vit E, 50+/-9; C, 70+/-16 nmol. min(-1). g(-1) dry tissue weight, P<0.05) and increased activation of SOD (vit C, 12+/-2; vit E, 8+/-1; C, 4.6+/-1 U/mg; P<0.05). Our results demonstrate that vitamins C and E reduce oxidative stress, improve vascular function and structure, and prevent progression of hypertension in SHRSP. These effects may be mediated via modulation of enzyme systems that generate free radicals.

Actin Directly Interacts with Phospholipase D, Inhibiting Its Activity

Mammalian phospholipase D (PLD) plays a key role in several signal transduction pathways and is involved in many diverse functions. To elucidate the complex molecular regulation of PLD, we investigated PLD-binding proteins obtained from rat brain extract. Here we report that a 43-kDa protein in the rat brain, beta-actin, acts as a major PLD2 direct-binding protein as revealed by peptide mass fingerprinting in combination with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. We also determined that the region between amino acids 613 and 723 of PLD2 is required for the direct binding of beta-actin, using bacterially expressed glutathione S-transferase fusion proteins of PLD2 fragments. Intriguingly, purified beta-actin potently inhibited both phosphatidylinositol-4,5-bisphosphate- and oleate-dependent PLD2 activities in a concentration-dependent manner (IC50 = 5 nm). In a previous paper, we reported that alpha-actinin inhibited PLD2 activity in an interaction-dependent and an ADP-ribosylation factor 1 (ARF1)-reversible manner (Park, J. B., Kim, J. H., Kim, Y., Ha, S. H., Kim, J. H., Yoo, J.-S., Du, G., Frohman, M. A., Suh, P.-G., and Ryu, S. H. (2000) J. Biol. Chem. 275, 21295-21301). In vitro binding analyses showed that beta-actin could displace alpha-actinin binding to PLD2, demonstrating independent interaction between cytoskeletal proteins and PLD2. Furthermore, ARF1 could steer the PLD2 activity in a positive direction regardless of the inhibitory effect of beta-actin on PLD2. We also observed that beta-actin regulates PLD1 and PLD2 with similar binding and inhibitory potencies. Immunocytochemical and co-immunoprecipitation studies demonstrated the in vivo interaction between the two PLD isozymes and actin in cells. Taken together, these results suggest that the regulation of PLD by cytoskeletal proteins, beta-actin and alpha-actinin, and ARF1 may play an important role in cytoskeleton-related PLD functions.

Src is an important mediator of extracellular signal-regulated kinase 1/2-dependent growth signaling by angiotensin II in smooth muscle cells from resistance arteries of hypertensive patients

The role of c-Src in growth signaling by angiotensin (Ang) II was investigated in vascular smooth muscle cells (VSMCs) from arteries of hypertensive patients. c-Src and extracellular signal-regulated kinase 1/2 (ERK1/2) activity, proto-oncogene expression, activating protein-1 (AP-1) DNA-binding activity, and DNA and protein synthesis were studied in Ang II-stimulated VSMCs derived from small peripheral resistance arteries of normotensive subjects (NTs, n=5) and age-matched untreated hypertensive patients (HTs, n=10). Ang II type 1 (AT(1)) and type 2 (AT(2)) receptor status was also assessed. Ang II dose-dependently increased the synthesis of DNA and protein, with enhanced effects in VSMCs from HTs. PD 098,059, a selective inhibitor of the ERK1/2 pathway, attenuated Ang II-stimulated growth in HTs. The effects of PD 098,059 were greater in HTs than in NTs. In NTs, Ang II transiently increased ERK1/2 phosphorylation, whereas in HTs, Ang II-stimulated actions were augmented and sustained. PP2, a selective Src inhibitor, reduced ERK1/2 activity and normalized ERK1/2 responses in HTs. Ang II-induced c-Src phosphorylation was 2- to 3-fold greater in HTs than in NTs. In HTs but not NTs, kinase activation was followed by overexpression of c-fos and enhanced AP-1 DNA-binding activity. PD 098,059 and PP2 attenuated these responses. AT(1) receptor expression was similar in NTs and HTs. In HT cells transfected with c-fos antisense oligodeoxynucleotide, Ang II-stimulated growth was reduced compared with sense oligodeoxynucleotide. Our findings suggest that augmented Ang II-stimulated VSMC growth is mediated via hyperactivation of c-Src-regulated ERK1/2-dependent pathways, leading to overexpression of c-fos mRNA and enhanced AP-1 DNA-binding activity. Because AT(1) receptor expression was unaltered in HTs, increased Ang II signaling may be a postreceptor phenomenon. These data define a signal transduction pathway whereby Ang II mediates exaggerated growth in VSMCs from HTs.

Sensitivity of leachate and fine contents on electrical resistivity variations of sandy soils

Laboratory pilot tests were performed to investigate the relationship between electrical resistivity and contaminated soil properties. Three different sandy soils and leachate collected from one of the industrial waste landfill sites in Korea were mixed to simulate contaminated soil conditions. The values of electrical resistivity of the soils were measured using laboratory scaled resistivity cone penetrometer probe. In the experiments, electrical resistivity was observed in terms of water content, unit weight, saturation degree of the soils, and leachate concentration. The experimental results show that the electrical resistivity of the sandy soils depends largely on the water content and electrical properties of pore water rather than unit weight and types of soils. The amount of fines can have significant effect on electrical properties of soils. Direct correlation with contamination in such soils may not be valid here. The results suggest that the electrical resistivity measurement is well suited and applicable for monitoring and delineation of contaminants in the subsurface.

ET(A) receptor antagonist prevents blood pressure elevation and vascular remodeling in aldosterone-infused rats

Increased endothelin-1 may be associated with elevation of blood pressure (BP) and promotion of vascular hypertrophy, especially in salt-sensitive hypertension. Mineralocorticoid hypertension has been associated with activation of the endothelin system. We evaluated whether in aldosterone-infused rats the selective endothelin type A receptor-antagonist BMS 182874 prevents BP elevation and vascular hypertrophy. Rats were infused with aldosterone (0.75 microg/h) subcutaneously via a mini-osmotic pump and were offered 1% NaCl in the drinking water+/-BMS 182874 (40 mg/kg in food) for 6 weeks. Systolic BP was monitored by the tail-cuff method, and vascular changes of mesenteric arteries were evaluated using a pressurized myograph. Aldosterone-infusion significantly increased BP to 151+/-7 mm Hg compared with controls (108+/-4 mm Hg, P<0.01). BMS 182874 normalized BP (117+/-4 mm Hg). Media cross-sectional area of aorta was significantly increased by aldosterone infusion (P<0.05), and BMS treatment normalized it (P<0.001). Aldosterone infusion increased media width and media-to-lumen ratio of mesenteric resistance arteries (17.6+/-0.4 microm and 7.5+/-0.4%) compared with controls (14.2+/-0.5 microm, P<0.01, and 5.9+/-0.1%, P<0.05). BMS 182874 normalized media and media-to-lumen ratio (15.1+/-0.6 microm and 5.7+/-0.1%, both P<0.01). In conclusion, the endothelin type A receptor antagonist attenuated BP elevation and prevented vascular remodeling or hypertrophy of aorta and mesenteric resistance arteries in aldosterone-infused rats. These results suggest a role for endothelin-1 in BP elevation and structural alterations of large and small vessels in aldosterone and salt-induced hypertension.

Small artery remodeling is the most prevalent (earliest?) form of target organ damage in mild essential hypertension

BACKGROUND

The heart and blood vessels are exposed to elevated blood pressure (BP) in hypertensive patients, but their changes in response to BP or non-hemodynamic stimuli may be different, and occur with different time-courses. To evaluate this, we studied the prevalence of structural and functional alterations of resistance arteries and cardiac hypertrophy in patients with mild essential hypertension.

METHODS

Resistance arteries were dissected from gluteal subcutaneous tissue from 38 hypertensive patients (47 +/- 1 years; 71% male; BP 148 +/- 2/99 +/- mmHg), studied on a pressurized myograph, and compared to those from 10 normotensives (44 +/- 3 years; 40% male; BP 113 +/- 4/76 +/- 2 mmHg).

RESULTS

The prevalence of abnormal structure (media-to-lumen ratio, M/L) and impaired endothelial function (maximal acetylcholine response) was 97 and 58% (abnormal was defined as greater than mean + 1 SD of normotensives), or 63 and 34% (abnormal defined as greater than mean +/- 2SD). Thirty four percent of hypertensive patients exhibited left ventricular hypertrophy by echocardiography. When grouped into tertiles according to increasing ambulatory systolic BP (SBP), the highest BP tertile showed increased M/L (P< 0.01) and left ventricular mass index (LVMI, P < 0.05) and marginally decreased endothelial function (P= 0.07). LVMI was greatest in the tertile of patients with highest M/L (P< 0.05). Endothelial function was decreased in the tertile with greatest vascular stiffness (P< 0.01). By multivariate analysis, M/L correlated with ambulatory SBP (beta = 0.40, P= 0.02), and LVMI correlated with ambulatory SBP (beta = 0.41, P = 0.001) and body mass index (beta = 0.30, P< 0.05). Female sex influenced endothelial function negatively (beta = -0.63, P< 0.01).

CONCLUSION

Structural alterations of resistance arteries were demonstrated in most hypertensive patients, followed by endothelial dysfunction and cardiac hypertrophy in a smaller number of hypertensives. Small artery structural remodeling may precede most clinically relevant manifestations of target organ damage in mild essential hypertension.

Electroconvulsive Shock Increases the Phosphorylation of Pyk2 in the Rat Hippocampus

Recently we reported the activation MAPKs, MEK, and Rafs by electroconvulsive shock (ECS) in the rat hippocampus. However, the upstream pathways for the activation of Raf-MEK-MAPK cascade after ECS have not been studied yet. Since the proline-rich tyrosine kinase 2 (Pyk2) and Src were reported to be involved in the activation of the MAPKs in neuronal cells, we examined tyrosine phosphorylation and activation of Pyk2 in the rat hippocampus after ECS. ECS transiently increased the phosphorylation of Pyk2 at multiple tyrosine residues (Tyr-402, Tyr-580, and Tyr-881). The phosphorylations reached the peak at 1 min and returned to basal level by 10 min after ECS. At 1 min after ECS, the binding of Pyk2 to Src and Grb2, and of Grb2 to Ras increased. These results suggested that ECS activates Pyk2, which then transmits the signal to MAPK cascade via Src, Grb2, and Ras in the rat hippocampus.

Post-transcriptional control of c-erb B-2 overexpression in stomach cancer cells

The growth factor receptor oncogene, c-erb B-2, is frequently overexpressed in the adenocarcinomas of breast, ovary, lung and stomach. Although the mechanism of erb B-2 overexpression is thought as the result of transcriptional upregulation in many primary human carcinomas, expression rate of c-erb B-2 at mRNA level is usually lower than the level of translated protein. We also found that the expression of erb B-2 in SNU-1 stomach cancer cells was greater at post-transcription level (Bae et al., 1993). To explore the underlying mechanism of erb B-2 protein overexpression, we have chosen two cells lines, SNU-1 and SNU-16 where transcription rate of erb B-2 was closely resemble to each other while expressed protein levels were quite different. The synthesis rate of erb B-2 protein in SNU-1 cells was faster than SNU-16 cells while levels of erb B-2 mRNA were found to be similar in both cell lines. The half-life of the expressed erb B-2 protein was not significantly different in both cell lines. Analysis of the 5' untranslated region (UTR) of erb B-2 mRNA (-1approximately-323) showed no sequence abnormality in both cell lines. However, ribonuclease protection assay using cloned 5 UTR sequence revealed that the size of 5' UTR of erb B-2 mRNA which associate with transcription initiation site(s) in SNU-1 cells was longer than that in SNU-16. These results suggest that the increased erb B-2 protein synthesis rate possibly due to the redundant selection of transcription initiation might be a mechanism of erb B-2 overexpression in SNU-1 cells.

Regulation of GTP-binding state in RalA through Ca2+ and calmodulin

RalA GTPase, a member of Ras superfamily proteins, shows alternative forms between the active GTP-binding and the inactive GDP-binding states. Ral-specific guanine nucleotide exchange factor such as RalGDS interacts with activated Ras and cooperates with Ras indicating that Ral can be activated through Ras signaling pathway. Another activation path for Ral are through Ca2+-dependent but Ras-independent manner. In this study, studies were carried out to examine possible effects of Ca2+ and calmodulin, Ca2+-binding protein, directly on the GTP/GDP-binding state to recombinant unprenylated GST-RalA proteins. The results showed that Ca2+ stimulated the binding of GTP to RalA, whereas it reduced the binding of GDP to RalA. However, it does not involve a high affinity association of Ca2+ with RalA. Ca2+/calmodulin stimulated the GTPase activity of RalA. These results indicate that Ca2+ alone activates RalA by stimulating GTP-binding to RalA and Ca2+/calmodulin inactivates RalA by increasing the activity of RalGTPase.

Expression of Fas ligand and apoptosis of disc cells in herniated lumbar disc tissue

STUDY DESIGN

An examination of surgically obtained herniated lumbar disc tissues performed by using immunohistochemical staining and the DNA nick end labeling method.

OBJECTIVE

To investigate the cell type that expresses Fas ligand (FasL) and any evidence of apoptosis of the disc cells in herniated lumbar disc tissues.

SUMMARY OF BACKGROUND DATA

The Fas/FasL system is involved in delivering a death signal that rapidly commits the cells to apoptosis. In the authors' previous study, the expression of Fas on disc cells was identified in herniated lumbar disc tissue.

METHODS

Twenty-three herniated lumbar disc tissues (contained disc, n = 9; noncontained disc, n = 14) were examined to investigate the cell type that expresses FasL and any evidence of apoptosis of the disc cells by using immunohistochemical staining and the DNA nick end labeling method, respectively. The percentage of FasL-positive disc cells was calculated and compared with clinical and radiologic data.

RESULTS

FasL was expressed in the cytoplasm of the disc cells, and nuclear DNA fragmentation in a few disc cells was identified. A higher degree of FasL expression in disc cells was found in noncontained discs than in contained discs (P < 0.05). The percentage of FasL-positive disc cells significantly increased with the patient's age (P < 0.05), but not with the degree of disc degeneration (P > 0.05).

CONCLUSION

The current results indicate that disc cells, after herniation, undergo apoptotic cell death via autocrine or paracrine FasL mechanisms by the disc cells themselves.

Facet tropism: a comparison between far lateral and posterolateral lumbar disc herniations

STUDY DESIGN

An assessment of the difference in the degree of facet tropism and disc degeneration between far lateral and posterolateral lumbar disc herniations.

OBJECTIVE

To investigate the effect of the difference in the degree of the facet tropism and disc degeneration with respect to the development of far lateral lumbar disc herniation and posterolateral lumbar disc herniation, and to compare the effect between the two types of herniations.

SUMMARY OF BACKGROUND DATA

The effect of facet tropism on the development of posterolateral lumbar disc herniation has been investigated previously, but there has been no study on far lateral lumbar disc herniation.

METHODS

Thirty-eight lumbar disc herniations (far lateral, n = 19; posterolateral, n = 19) were included this study. The degree of facet tropism and disc degeneration was measured at the herniated disc level by using magnetic resonance imaging. The results were compared to show any differences between the two types of lumbar disc herniations.

RESULTS

There were significant differences in the degree of facet tropism (24.74 vs. 14.26, P = 0.004) and disc degeneration (23.92 vs. 15.08, P = 0.005) between the far lateral and posterolateral lumbar disc herniations. There was no significant correlation between the degree of facet tropism and the degree of disc degeneration in far lateral lumbar disc herniation (r = -0.369, P = 0.120).

CONCLUSION

This results suggest that the differences in the degree of facet tropism and disc degeneration might be considered a key factor in distinguishing the development of far lateral lumbar disc herniation from that of posterolateral lumbar disc herniation.

Correlation of endothelial function in large and small arteries in human essential hypertension

OBJECTIVES

The structure and function of blood vessels varies along the vascular tree, and alterations found in hypertension are also different. The aim of this study was to determine whether non-invasive measurement of endothelial function in conduit arteries reflects that of subcutaneous resistance arteries measured in vitro.

METHODS AND RESULTS

Sixteen essential hypertensive patients (aged 50 +/- 2 years) were studied. Flow-mediated dilation (FMD) during reactive hyperemia (endothelium-dependent) and sublingual nitroglycerin (NTG)-induced dilatation (endothelium-independent) were assessed in brachial arteries by ultrasound. Structure, and acetylcholine (10(-9) to 10(-4) mol/l) and sodium nitroprusside (SNP, 10(-8) to 10(-3) mol/l)-induced vasorelaxation of resistance arteries dissected from gluteal subcutaneous biopsies were measured in vitro using a pressurized myograph. Brachial artery FMD and NTG-induced dilatation were 8.4 +/- 1.0 and 18.1 +/- 1.4%, respectively. Resistance arteries of hypertensive patients showed greater media:lumen ratio (8.6 +/- 0.4 versus 5.9 +/- 0.3% in normotensive subjects, P< 0.01), and maximal acetylcholine responses was diminished to 75 +/- 6% compared to normotensive subjects (97 +/- 2%, P< 0.01). FMD correlated with maximal acetylcholine responses (r2 = 0.57, P< 0.001). FMD did not correlate significantly with the media: lumen ratio of resistance arteries (r2 = -0.22, P= 0.07). By multivariate analysis, FMD predicted resistance artery endothelial function independently of age, sex, body mass index, blood lipid status and lumen diameter of brachial artery (beta = 0.81, P< 0.001).

CONCLUSIONS

Endothelial dilatory responses are similar in large and small arteries in hypertensive patients. Abnormal FMD in the brachial artery predicts the presence of endothelial dysfunction in human resistance arteries, suggesting that impairment of endothelial function is a generalized alteration in hypertension. Ultrasound measurement of endothelial dysfunction in the brachial artery appears to be less sensitive than in-vitro measurement in resistance arteries.

Role of c-Src in the regulation of vascular contraction and Ca2+ signaling by angiotensin II in human vascular smooth muscle cells

OBJECTIVE

Tyrosine kinases, typically associated with growth-signaling pathways, also play a role in Ang II-stimulated vascular contraction. However the specific kinases involved are unclear. We hypothesize here that c-Src, a non-receptor tyrosine kinase, is an important upstream regulator of vascular smooth muscle cell (VSMC) Ca2+ signaling and associated vascular contraction induced by Ang II.

METHODS

Cultured VSMCs from resistance arteries of healthy subjects were studied. Human VSMCs electroporated with anti-c-Src antibody and c-Src-deficient VSMCs from small arteries of c-Src knockout mice (Src-/-mVSMCs) were also investigated. Intracellular free Ca2+ concentration ([Ca2+]i), c-Src activity and IP3 production were measured by fura 2, immunoblot and radioimmunoassay respectively. Contraction was examined in intact rat small arteries.

RESULTS

Ang II rapidly increased VSMC c-Src activity, with peak responses obtained at 1 min. Ang II induced a biphasic [Ca2+]i response (Emax = 636 +/- 123 nmol/l). The initial [Ca2+]i transient, mediated primarily by Ca2+mobilization, was dose-dependently attenuated by the selective Src inhibitor, PP2, but not by PP3 (inactive analogue). Ang II-elicited [Ca2+]i responses were blunted in cells electroporated with anti-c-Src antibodies and in c-Src-/-mVSMCs. Src inhibition decreased Ang II-induced generation of IP3 in human VSMCs. Ang II dose-dependently increased vascular contraction (Emax = 40 +/- 6.5%). These responses were attenuated by PP2 (Emax = 7.8 +/- 0.08%) but not by PP3 (Emax = 35 +/- 4.5%).

CONCLUSIONS

Our findings identify c-Src as an important regulator of VSMC [Ca2+]i signaling and implicate a novel contractile role for this non-receptor tyrosine kinase in Ang II-stimulated vascular smooth muscle.

Inhibition of glucose and dehydroascorbic acid uptakes by resveratrol in human transformed myelocytic cells

Resveratrol (trans-3,5,4'-trihydroxystilbene) is a natural phytochemical found in grapes and wine. Numerous biological effects of resveratrol have been reported in the last 10 years. In this paper, the competitive inhibition of intracellular uptake of glucose and dehydroascorbic acid in U937 and HL-60 cells by resveratrol is reported.

Defining the heating characteristics of ferromagnetic implants using calorimetry

The induction heating of small, cylindrical ferromagnetic implants for localized tumors is currently under investigation. These thermal rods are implanted within a lesion in 1 cm(2) arrays and subsequently exposed to an externally applied alternating magnetic field. Implants absorb energy from the field and transfer it as heat to the surrounding tissue. To achieve a uniform temperature rise throughout the tissue volume and to account for any field-rod misalignment, 400 mW of power per implant is used as the design specification. The temperature to necrose cells must be greater than 46 degrees C. A calorimeter was constructed to confirm that the rod power output specification is satisfied at temperatures adequate for inducing cell death. The rods were designed to undergo a ferromagnetic to paramagnetic transition at temperatures of 55 degrees C, 60 degrees C, 65 degrees C, and 70 degrees C; this transition produces rods that are temperature self-regulating. Calorimetric results demonstrated that 55 degrees C, 60 degrees C, 65 degrees C, and 70 degrees C rods provided 400 mW at 47-51 degrees C, 51-53.5 degrees C, 57 degrees C, and 62.5-63.5 degrees C, respectively. Thermal rods provide sufficient power output at the temperatures necessary to cause thermal ablation of tumors. The higher-temperature rods give a greater margin to ensure that necrotizing temperatures can be achieved throughout the rod array even with minor misalignment.

Interfacial strength of compression-molded specimens between PMMA powder and PMMA/MMA monomer solution-treated ultra-high molecular weight polyethylene (UHMWPE) powder

The interface between bone cement and ultra-high molecular weight polyethylene (UHMWPE) has been considered a weak link of cemented UHMWPE acetabular cup in total hip replacement (THR). For the improvement of this weak interface, adhesion between the UHMWPE acetabular cup and bone cement made of polymethylmethacrylate (PMMA) has been investigated in our laboratory. Virgin UHMWPE powders were treated with methyl methacrylate (MMA) monomer and PMMA/MMA solution. The treated UHMWPE powders were then compression-molded with virgin UHMWPE powders or PMMA powders, creating two different interfaces, i. e., treated/virgin UHMWPE powder and treated UHMWPE/PMMA powder. For the present study, the interfacial strengths between PMMA powder and the treated UHMWPE power were investigated following the same protocol previously set. The maximum interfacial strength was 17.0 +/- 0.25MPa with the same molding condition of 166.5 degrees C, 38.7 MPa and l h. In addition to the molding condition, we tested the strengths for the treated UHMWPE powders, which have different ratios between PMMA/MMA solution and MMA-treated UHMWPE powders. Significant differences on the interfacial strengths resulted due to the ratio change; more PMMA in the PMMA/MMA solution-treated UHMWPE powder exhibited higher interfacial strength. Scanning electron microscopic (SEM) pictures showed that the interface is composed of three major portions: PMMA powder, UHMWPE, and coated PMMA, indicating strong mechanical interlocking of UHMWPE and PMMA powder matrix and chemical bonding between PMMA powder and the precoated PMMA onto the UHMWPE. In addition, another interfacial strength between PMMA powder, which is equivalent to the outermost part of the cup, and bone cement was investigated. The average strength reached up to 42.4 +/- 3.6 MPa, close to the tensile strength of bone cement itself.

Reduction of dehydroascorbic acid by homocysteine

To determine the reductive process of extracellular dehydroascorbic acid (DHA), molecules (homocysteine, homocysteine thiolactone, methionine, cysteine, and homoserine) were tested to identify those with the potential to reduce DHA to ascorbic acid (AA). Homocysteine (Hcy) was the most potent of the molecules tested. The efficacy of Hcy was compared with that of other molecules able to reduce DHA (reduced glutathione (GSH) and cysteine (Cy)). Although all three molecules were able to reduce DHA, GSH and Cy were not to reduce DHA to AA at concentrations lower than 100 micromol/l, and only less than 5% DHA was reduced to AA at concentrations of 200-300 micromol/l. In contrast, Hcy reduced DHA to AA stoichiometrically at concentrations as low as 10 micromol/l. In Jurkat and U937 cells, the increasing concentrations of extracellular Hcy suppressed intracellular dehydroascorbic acid uptake, indicating that extracellular reduction of DHA by Hcy leads to decreasing extracellular DHA available for its intracellular uptake. Simultaneous oxidation and reduction of Hcy and DHA were accelerated extracellularly in the presence of quercetin, an inhibitor of DHA uptake, suggesting that extracellular ascorbic acid concentration increased via blocking DHA uptake by quercetin and reducing extracellular DHA by Hcy. The effect of homocysteine on DHA reduction and uptake was confirmed with human umbilical vein endothelial cells. The oxidation of Hcy also prevented the decrease in DNA synthesis in human umbilical vein endothelial cells, which would occur following exposure to Hcy.

Expression of Fas receptor on disc cells in herniated lumbar disc tissue

STUDY DESIGN

The expression of Fas receptor, an apoptosis-related protein, on disc cells was examined in surgically obtained disc specimens.

OBJECTIVE

To assess the fate of disc cells in herniated disc tissue and the difference in the degree of expression of the Fas receptor between contained and noncontained discs.

SUMMARY OF BACKGROUND DATA

Little is known about the fate of disc cells after herniation.

METHODS

Twenty-three herniated lumbar disc specimens were classified into contained discs (protrusion or subligamentous extrusion; n = 9) and noncontained discs (transligamentous extrusion or sequestration; n = 14). All specimens were stained using the avidin-biotin-peroxidase complex method. The percentage of disc cells positive for Fas receptor was calculated and compared with clinical and radiologic data.

RESULTS

There was a significant difference in the percentage of Fas-positive disc cells between the contained and noncontained discs (8.44 vs.- 14.29;P = 0.044). The percentage of Fas-positive disc cells correlated significantly with the patient's age (r = 0.455, P = 0.029), but not with the degree of disc degeneration on magnetic resonance imaging (r = 0.252, P = 0.214).

CONCLUSION

This is the first study to identify the expression of Fas receptor on disc cells in herniated disc tissue. The results show that the disc cells after herniation may undergo Fas-mediated apoptosis and that the degree of expression of Fas receptor differs depending on the type of herniation.

Activation of JNK and p38 in rat hippocampus after kainic acid induced seizure

Kainic acid, an analogue of glutamate, causes limbic seizures and induces cell death in the rat brain. We examined the activation of MAPK family kinases; ERKs, JNKs and p38 kinase in rat hippocampus after KA treatment. Activation of all three kinases were observed at 30 min after the treatment, but, in contrary to ERK phosphorylation, which lasted up to 3 h, the phosphorylation of JNK and p38 returned to the basal level by 2 h. The phosphorylation of' upstream kinases for the MAPK family was distinct. The phosphorylation of MEK1 clearly increased at 30 min but diminished rapidly thereafter. The phosphorylation of MKK6 was also increased but reached peak at 2 h after KA treatment. However, the phosphorylation of other upstream kinases, SEK1 and MKK3, gradually decreased to 3 h after KA treatment. These results indicate that the KA activates all of the three MAPK family kinases with different time patterns and suggest the possibility that MKK3 and MKK6, and SEK1 may not be the upstream kinases for p38 and JNK in rat hippocampus.

Effect of Korean red ginseng on blood pressure and nitric oxide production

AIM

To investigate the effect of crude saponin and nonsaponin fraction of Korean red ginseng (KRG) on the blood pressure and nitric oxide (NO) production in the conscious rats and cultured endothelial cell line, ECV 304 cells.

METHODS

Systolic blood pressure and heart rate were monitored in the conscious rats. Nitric oxide levels and the expression of nitric oxide synthase were measured by a spectrophotometric assay using Griess reagents and Western blotting, respectively. Nitric-oxide synthase activity was measured based on the conversion rate of [3H]arginine to [3H]citrulline.

RESULTS

Systolic blood pressure was decreased by crude saponin (100 mg/kg, i.v.) of KRG in the conscious control and one-kidney, one-clip Goldblatt hypertensive (1K, 1C-GBH) rats. The hypotensive effect induced by crude saponin of KRG reached maximum at 2-4 min and slowly recovered after 20 min to the initial level in both groups. Crude saponin of KRG induced tachycardia in the conscious rats but induced bradycardia in the anesthetized rats. In contrast to crude saponin of KRG, hypotensive effect induced by saponin-free fraction was minimal. Nitric oxide concentrations were increased by the treatment of crude saponin in conscious rats as well as in the cultured ECV 304 cells. The protein expression level of endothelial constitutive nitric-oxide synthase (eNOS) in the aorta of rats was not increased by crude saponin (100 mg/kg, i.p. for 3 d). However, nitric-oxide synthase activity was increased by crude saponin of KRG in the aortic homogenate of rats.

CONCLUSION

The hypotensive effect of red ginseng is mainly due to saponin fraction of KRG in the conscious rats, and this effect may be due to an increase in the nitric-oxide production by KRG.

5-Aza-2'-deoxycytidine leads to down-regulation of aberrant p16INK4A RNA transcripts and restores the functional retinoblastoma protein pathway in hepatocellular carcinoma cell lines

The inactivation of the cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor p16INK4A may be caused by gene deletion, mutation or promoter hypermethylation. We have previously reported that p16INK4A in hepatocellular carcinoma (HCC) tissues and cell lines is inactivated predominantly by promoter hypermethylation rather than genomic aberrations. In the present experiments, we have studied the effects of the demethylating agent, 5-aza-2'-deoxycytidine (5-AZA/decitabine), on the expression of aberrant p16INK4A RNA transcripts and the CDK-retinoblastoma gene pathway in HCC cell lines with p16INK4A promoter hypermethylation. The expression of aberrant p16INK4A RNA transcripts was down-regulated and p16INK4A protein was strongly re-expressed in the HCC cell lines, SNU 354, 398, 423 and 475 after 5-AZA/decitabine treatment for 5 days. The re-expressed p16INK4A was functional, because it bound to and inhibited CDK4 kinase activity, and increased the concentrations of the hypophosphorylated form of retinoblastoma protein (pRB) in cells with a wild type RB gene. Moreover, treatment with the demethylating agent led not only to G1 cell cycle arrest, but also to the increased expression of the senescence-associated marker beta-galactosidase. This up-regulation of p16INK4A mRNA and protein correlated with demethylation of the p16INK4A promoter, and with the down-regulation or disappearance of aberrant p16INK4A transcripts. These results suggest that the aberrant p16INK4A RNA transcript can be transcribed from the methylated p16INK4A gene, and endogenous reactivation of functional p16INK4A mRNA by a demethylating agent can restore the pRB pathway in HCC, and foster the terminal differentiation of the malignant cells. Therefore, demethylating agents, such as 5-AZA/decitabine, may have potential in the treatment of HCC.

Retro-dental reactive lesions related to development of myelopathy in patients with atlantoaxial instability secondary to Os odontoideum

STUDY DESIGN

A retrospective analysis of 13 patients with atlantoaxial instability secondary to Os odontoideum who underwent posterior atlantoaxial fusion.

OBJECTIVE

To assess the relationships between the development of myelopathy and plain radiographic parameters in patients with atlantoaxial instability secondary to Os odontoideum and to determine whether the pathologic structures, which compress the spinal cord, are visualized using magnetic resonance imaging.

SUMMARY OF BACKGROUND DATA

The development of myelopathy, which is the most serious complication associated with Os odontoideum, was thought to be related to either the degree of instability or direction of instability, or a decrease in the space available for the cord. However, such indirect radiographic parameters measured using plain radiographs cannot provide direct information concerning the causes of myelopathy in patients with atlantoaxial instability secondary to Os odontoideum.

METHODS

Thirteen patients who underwent posterior atlantoaxial fusion for clinical symptoms due to Os odontoideum were classified into two groups depending on whether they had (n = 9) or did not have (n = 4) myelopathy. Four radiographic parameters were measured using flexion and extension lateral radiographs; the degree of instability, the direction of instability, and the space available for the cord in flexion and extension. MRI was performed on all patients in the myelopathy group. The radiologic and clinical data were compared for the two groups.

RESULTS

There were no significant statistical differences in the degree of instability (6.83 vs. 7.38, P = 0.816), space available for the cord in flexion (6.94 vs. 7.13, P = 0.938), and space available for cord in extension (7.56 vs. 5.75, P = 0.434) between the two groups. There was a poor agreement between the direction of instability and the development of myelopathy (kappa = 0.268, P = 0.308). Magnetic resonance imaging did demonstrate, however, cord compression caused by retro-dental reactive lesions in the myelopathy; cystic masses were present in two patients; and fibrocartilaginous masses were present in seven.

CONCLUSION

The current study suggests that the value of plain radiographic parameters should be reevaluated as a means of evaluating myelopathy in patients with atlantoaxial instability secondary to Os odontoideum, and that retro-dental reactive lesions should be considered as the potential cause of myelopathy.

Molecular cloning and sequencing of rat Cdc42 GTPase cDNA

Cdc42 is a member of the Rho family of small GTP-ase and plays an important role in intracellular signaling pathways regulating cell morphology, motility and stimulation of DNA synthesis. We have isolated cDNA encoding Cdc42 from a rat brain cDNA library using PCR-cloning strategy. The sequence of isolated gene revealed an open reading frame of 576 nucleotides with the potential to encode a protein of 191 amino acids with a predicted molecular weight of 21 kD. The resulting sequence was incorporated into the GenBank with accession number, AF205635. Sequence analysis revealed that overall cDNA sequence identity is 96% with human G25K and 52% with rat Chp, a homologue of the GTPase human Cdc42Hs, and having one nucleotide difference from the mouse Cdc42. However, putative protein sequence was identical to the mouse and human brain Cdc42Hs. On expression of the cDNA in COS-7 cells, a protein molecular weight of 21 kD was detected in immunoblotting using anti-human Cdc42 antibodies. Therefore, these results suggest that the cDNA we are reporting is most likely the rat homologue of the GTPase human Cdc42.

Differential activation of c-Jun NH2-terminal kinase and p38 mitogen-activated protein kinases by methyl methanesulfonate in the liver and brain of rats: implication for organ-specific carcinogenesis

Methyl methanesulfonate (MMS), a direct-acting alkylating agent, is a strong brain carcinogen but a poor hepatocarcinogen in rats. To elucidate the mechanism(s) leading to tissue-specific carcinogenesis in response to MMS, we compared the activation of the stress-activated protein kinases (SAPKs), the c-Jun NH2-terminal kinase (JNK) and p38, in the liver and brain of rats after i.p. injection of MMS. p38 was activated in both the liver and brain, but JNK was activated only in the liver in a dose- and time-dependent manner. The activation of JNK was preceded by the activation of SAPK or extracellular signal-regulated protein kinase kinase 1/mitogen-activated protein kinase kinase 4 in the liver, but no activation of SAPK or extracellular signal-regulated protein kinase kinase 1/mitogen-activated protein kinase kinase 4 was observed in the brain. The activation of JNK in the liver was accompanied by increased phosphorylation of activating transcription factor 2 and followed by an increase in the phosphorylation and level of c-Jun protein, in contrast to no such changes in the brain. To study the physiological consequences of these differential molecular events in the liver and brain, we examined MMS-induced apoptosis, a process shown to involve stress kinase activation. A significant increase in apoptotic cell death was detected in the liver but not in the brain after a MMS injection, which correlated with the patterns of JNK activation in the liver. Taken together, our results demonstrate that a tissue-specific signaling pathway(s) leading to distinct physiological responses in the liver and brain of rats exposed to MMS exists, suggesting a possible explanation for tissue-specific carcinogenic effects exerted by MMS in vivo.

Effect of Korea red ginseng on the blood pressure in conscious hypertensive rats

The change of blood pressure and heart rate after intravenous injection of Korea red ginseng (KRG) were studied in the conscious normotensive and one-kidney, one-clip Goldblatt hypertensive (1K, 1C-GBH) rats. Crude saponin (CS) of KRG (50, 100 mg/kg i.v.) induced a hypotensive effect and bradycardia in a dose-dependent manner in the anesthetized rats. On the other hand, CS of KRG (100 mg/kg) induced a hypotensive effect and reflex tachycardia in the conscious rats. Saponin-free fraction (SFF) of KRG did not affect them in the anesthetized normotensive rats (P>.05). The maximal hypotensive effect by CS of KRG in the conscious 1K, 1C-GBH hypertensive rats and L-nitroarginine methyl ester (L-NAME, 40 mg/kg)-treated conscious hypertensive rats was not different from that of conscious normotensive rats (Delta 31.6+/-6.3, Delta 27.5+/-5.8 vs. Delta 26.7+/-4.3 mmHg, P>.05). However, pretreatment of L-NAME significantly inhibited the reflex tachycardia by CS of KRG (70.8+/-7.0 vs. 30.6+/-15.0 bpm, P<.05). Hemolysate-sensitive nitric oxide (NO) current by the CS of KRG was greater than that of the SFF of KRG (651.9+/-128.2 pA for CS and 164.9+/-92.5 pA for SFF, P<.001). These findings suggest that KRG has a hypotensive effect and its effect may be due to saponin fraction of KRG in the conscious rats. The releasing effect of NO of KRG, like NO donor, may be partly contributed to the hypotensive effect of KRG.

Localization of the cyclic ADP-ribose-dependent calcium signaling pathway in hepatocyte nucleus

CD38 is a type II transmembrane glycoprotein found on both hematopoietic and non-hematopoietic cells. It is known for its involvement in the metabolism of cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate, two nucleotides with calcium mobilizing activity independent of inositol trisphosphate. It is generally believed that CD38 is an integral protein with ectoenzymatic activities found mainly on the plasma membrane. Here we show that enzymatically active CD38 is present intracellularly on the nuclear envelope of rat hepatocytes. CD38 isolated from rat liver nuclei possessed both ADP-ribosyl cyclase and NADase activity. Immunofluorescence studies on rat liver cryosections and isolated nuclei localized CD38 to the nuclear envelope of hepatocytes. Subcellular localization via immunoelectron microscopy showed that CD38 is located on the inner nuclear envelope. The isolated nuclei sequestered calcium in an ATP-dependent manner. cADPR elicited a rapid calcium release from the loaded nuclei, which was independent of inositol trisphosphate and was inhibited by 8-amino-cADPR, a specific antagonist of cADPR, and ryanodine. However, nicotinic acid adenine dinucleotide phosphate failed to elicit any calcium release from the nuclear calcium stores. The nuclear localization of CD38 shown in this study suggests a novel role of CD38 in intracellular calcium signaling for non-hematopoietic cells.

Cardiac phospholipase D2 localizes to sarcolemmal membranes and is inhibited by alpha-actinin in an ADP-ribosylation factor-reversible manner

Myocardial phospholipase D (PLD) has been implicated in the regulation of Ca(2+) mobilization and contractile performance in the heart. However, the molecular identity of this myocardial PLD and the mechanisms that regulate it are not well understood. Using subcellular fractionation and Western blot analysis, we found that PLD2 is the major myocardial PLD and that it localizes primarily to sarcolemmal membranes. A 100-kDa PLD2-interacting cardiac protein was detected using a protein overlay assay employing purified PLD2 and then identified as alpha-actinin using peptide-mass fingerprinting with matrix-assisted laser desorption/ionization mass spectroscopy. The direct association between PLD2 and alpha-actinin was confirmed using an in vitro binding assay and localized to PLD2's N-terminal 185 amino acids. Purified alpha-actinin potently inhibits PLD2 activity (IC(50) = 80 nm) in an interaction-dependent and ADP-ribosylation factor-reversible manner. Finally, alpha-actinin co-localizes with actin and with PLD2 in the detergent-insoluble fraction from sarcolemmal membranes. These results suggest that PLD2 is reciprocally regulated in sarcolemmal membranes by alpha-actinin and ARF1 and accordingly that a major role for PLD2 in cardiac function may involve reorganization of the actin cytoskeleton.

Presentation and mortality of primary biliary cirrhosis in older patients

OBJECTIVES

many patients with primary biliary cirrhosis present for the first time aged over 65, but it is unclear whether the disease is different in older patients. We have examined presentation and mortality in relation to age at which primary biliary cirrhosis was first suspected clinically.

DESIGN

we identified 1023 patients from our regional primary biliary cirrhosis database with definite or probable primary biliary cirrhosis (689 definite); 397 (39%) presented aged > or =65. Definite primary biliary cirrhosis was defined as a positive antimitochondrial antibody titre > or =1/40, abnormal liver enzymes and compatible/diagnostic histology; probable as the presence of two of these indications.

RESULTS

there was no difference in presenting clinical features between the older and younger groups. Older patients were significantly less likely than younger to have had liver biopsy (50% vs 78%; P < 0.001). The 1023 patients had been followed for 8561 patient years. Follow-up was shorter (5.9+/-4 vs 9.8+/-5.5 years; P < 0.001) in the older group because of higher cumulative mortality (59% vs 33%; P < 0.001). Liver-related deaths were significantly commoner in the older group (18% vs 13%; P < 0.05). The mortality ratio for liver deaths (liver deaths per year of follow-up) was 2.4 times higher in the older group (0.031 vs 0.013).

CONCLUSIONS

patients with primary biliary cirrhosis who are over and under 65 have similar features on presentation. The annual risk of liver death is 2.4 times higher in those presenting over 65, reaffirming the importance of age as an independent prognostic factor in an unselected primary biliary cirrhosis population.

Mutation and expression of the p27KIP1 and p57KIP2 genes in human gastric cancer

Cyclin-dependent kinase inhibitors (CDKI) are negative regulators of cell cycle progression by binding the cyclin-CDK complex and inhibiting the CDK activity. Genetic alteration in the CDKI genes has been implicated for carcinogenesis. To test the genetic alteration in the p27 and p57 genes, KIP family CDKI genes, 30 gastric tumor-normal pairs and 8 gastric cancer cell lines were analyzed for mutations by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP). No mutation was detected in these genes although length polymorphisms in the proline-alanine repeat of the p57 gene were detected. When the p27 and p57 mRNAs were analyzed in gastric cancer cell lines by RT-PCR, the p27 mRNA was expressed considerably high in tumor cells but expression of the p57 mRNA was much low in gastric cancer cell lines compared to that of normal cells. The result suggests that inactivation of gene expression rather than mutations in the p57 gene accounts possibly for the involvement of this gene in tumorigenesis of gastric cancer. However, expression of the p27 gene seems to be essential for cell survival.

Precoating of ultrahigh molecular weight polyethylene with polymethylmethacrylate: interfacial strength

Fixation of polymeric implants, especially an ultrahigh molecular weight polyethylene (UHMWPE) acetabular cup, to a host bone site has been a challenge since its first conception from the Charnley low friction total hip arthroplasty. Destabilization of the acetabular cup, similar to the well-documented cases of femoral stems, is caused mainly by aseptic loosening; the mobile loosened particles further contribute to the progression of aseptic loosening. Although the obvious fixation problems lie in the bone-bone cement interface, little work has been done to reduce the loosening by improving the acetabular components as a whole in cemented procedures. Most of the grooved outer surface, external fixation devices, and metal backings have been introduced to avoid problematic fixation of the cup to bone cement; nevertheless, the designs themselves to some degree became the source of the loosening problems. One possible way to improve the adhesion of acrylic bone cement to the UHMWPE acetabular cup is precoating the surface with polymethylmethacrylate (PMMA). This study successfully precoated the UHMWPE surface with PMMA, showing good chemical and mechanical stability, and suggests the optimal conditions of variables involved in the newly developed precoating process. The highest interfacial tensile strength was 11.51 +/- 0.65 MPa, which is stronger than those of UHMWPE and metal in metal-backed cups (6.3 MPa) and bone-bone cement (8.5 MPa). Further chemical analysis and mechanical testing are in progress, yet the present result of the mechanical tensile strength test showed that the precoating process for the UHMWPE surface could be a viable means toward stable fixation of the polymeric implants by using PMMA bone cement.

Materials and design of spinal implants--a review

Man-made devices have been implanted into the body to relieve pain, to restore function, and to facilitate healing. The subjects of this review are the materials, and to a lesser extent, the design aspects of the numerous implants that are available to the surgeon in dealing with the ailing spine. Often it is the material aspects of such devices that are responsible for their success or failure. It may be that osteoconductive properties are desired for implants to assist fusion, whereas as inert a material as possible would be preferred for interpositional barriers. The materials composing the instrumentation used to facilitate healing of spinal fractures would ideally have properties that optimize strength and biocompatibility, while at the same time minimizing imaging artifacts and allowing a gradual transfer of load from the instrumentation to the vertebral body (i.e., viscoelastic effects). The application of biomaterials and biomechanics to the design of spinal devices is obvious; what may be more subtle though is what the in vivo interactions of these will be. The study of such aspects must continue in order to better evolve the designs and subsequent results of implanted spinal devices.

Interfacial strength between molded UHMWPE and PMMA-MMA monomer treated UHMWPE

To solve aseptic loosening of cemented acetabular cup and tibial plateaus of hips and knee joint prostheses in total joint replacement, adhesion between the polymeric prostheses made of ultra-high molecular weight polyethylene (UHMWPE) and bone cement made of polymethyl-methacrylate (PMMA) has been investigated. Previous studies using xylene, PMMA, and MMA monomer solution to treat bulk surfaces of UHMWPE resulted in 11.5 +/- 0.65 MPa as the maximum interfacial strength between the treated UHMWPE and bone cement. The present study eliminates the use of xylene; instead, UHMWPE powders were treated with MMA monomer and PMMA-MMA solution, dried, and then compression-molded with untreated UHMWPE powders. The interfacial tensile strengths were measured and the best molding conditions investigated by varying temperature, pressure, and time. Temperature was the predominant factor when compared to that of pressure or time. The maximum interfacial strength between the treated UHMWPE and untreated UHMWPE was 16.3 +/- 0.94 MPa with the molding conditions of 166.5 degrees C, 38.7 MPa, and 1 h. Scanning electron microscopic (SEM) pictures show the coating of the nodules and fibrils of UHMWPE powder with PMMA. Pulled out aggregated nodular space and coated PMMA after fracture could be seen easily from PMMA-MMA treated UHMWPE powder.

Effects of antihypertensive therapy on hypertensive vascular disease

Hypertension is associated with alterations in the structure, function, and mechanical properties of large and small arteries. Changes in the endothelium, smooth muscle cell, extracellular matrix, and possibly the adventitia, contribute to complications of hypertension. In large arteries, vascular hypertrophy is found, often with increased stiffness of media components. In small arteries, particularly in mild hypertension, rearrangement of smooth muscle cells around a smaller lumen without changes in media volume (eutrophic remodeling) occurs; in more severe hypertension, hypertrophic remodeling with increased vascular stiffness can be found. Vascular remodeling is accompanied by an increase in the extracellular matrix, particularly collagen deposition. Recent studies have demonstrated that vascular remodeling and endothelial dysfunction of small and large vessels may be normalized by treatment with some antihypertensive agents (angiotensin converting enzyme inhibitors, angiotensin AT(1) receptor antagonists, and long-acting calcium channel blockers). Angiotensin converting enzyme inhibitors have now been shown to improve outcomes in hypertensive patients, an effect that may in part be related to the vascular protective effects reviewed here.

Activation of astroglial phospholipase D activity by phorbol ester involves ARF and Rho proteins

Primary cultures of rat cortical astrocytes express phospholipase D (PLD) isoforms 1 and 2 as determined by RT-PCR and Western blot. Basal PLD activity was strongly (10-fold) increased by 4beta-phorbol-12beta,13alpha-dibutyrate (PDB) (EC(50): 56 nM), an effect which was inhibited by Ro 31-8220 (0.1-1 microM), an inhibitor of protein kinase C (PKC), and by brefeldin A (10-100 microg/ml), an inhibitor of ADP-ribosylating factor (ARF) activation. Pretreatment of the cultures with Clostridium difficile toxin B-10463 (0.1-1 ng/ml), which inactivates small G proteins of the Rho family, led to a breakdown of the astroglial cytoskeleton; concomitantly, PLD activation by PDB was reduced by up to 50%. In contrast, inactivation of proteins of the Ras family by Clostridium sordellii lethal toxin 1522 did not affect PLD activation. In parallel experiments, serum-induced PLD activation was sensitive to brefeldin A, but not to Ro 31-8220 and not to clostridial toxins. We conclude that, in astrocytes, the PLD isoform which is activated by phorbol ester requires PKC, ARF and Rho proteins for full activity and probably represents PLD1.

Intracellular accumulation of ascorbic acid is inhibited by flavonoids via blocking of dehydroascorbic acid and ascorbic acid uptakes in HL-60, U937 and Jurkat cells

In HL-60, U937 and Jurkat cells, the intracellular accumulation of ascorbic acid occurred via uptakes of both dehydroascorbic acid (an oxidized metabolite of ascorbic acid) and ascorbic acid (vitamin C). Dehydroascorbic acid and ascorbic acid were transported into cells by sodium-independent glucose transporters (GLUT 1 and GLUT 3) and sodium-dependent ascorbic acid transporters, respectively. Flavonoids inhibited the intracellular accumulation of ascorbic acid by blocking dehydroascorbic acid and ascorbic acid uptakes in the transformed cells. At flavonoid concentrations of 10-70 micromol/L, approximately 50% of dehydroascorbic acid uptake was inhibited in the cells. In Jurkat cells, two potent flavonoids (myricetin and quercetin) competitively inhibited dehydroascorbic acid uptake, and K(i) values were approximately 14 and 15 micromol/L, respectively. Because GLUT 1 and GLUT 3 transport dehydroascorbic acid, the inhibition of dehydroascorbic acid uptake by flavonoids was investigated by using Chinese hamster ovary cells overexpressing rat GLUT 1 or human GLUT 3. Myricetin at concentrations of 22 and 18 micromol/L, respectively, inhibited half of dehydroascorbic acid uptake in the cells overexpressing GLUT 1 and GLUT 3. Myricetin also inhibited ascorbic acid uptake; inhibition was noncompetitive with K(i) = 14 micromol/L in Jurkat cells. These data indicate that flavonoids inhibit both ascorbic acid and dehydroascorbic acid uptake but do so by different mechanisms. These data may contribute to new understanding of the biological effect of flavonoids on the intracellular accumulation of ascorbic acid in human cells.

Intraosseous calcifying pseudotumor of the axis: a case report

STUDY DESIGN

A case report and review of the literature.

OBJECTIVE

To present the first case of intraosseous calcifying pseudotumor arising from the axis.

SUMMARY OF BACKGROUND DATA

Calcifying pseudotumor is a very rare disease. Only 24 cases have been previously reported.

METHODS

A case of calcifying pseudotumor involving the body, dens, and laminae of the axis in a 60-year-old male patient was managed with total laminectomy of the axis and instrumented occipitocervical fusion, followed by the curettage of the body and dens of the axis and autogenous iliac bone graft. Medical records, imaging studies, microscopic findings, and related literature are reviewed.

RESULTS

Microscopic examination showed amorphous, basophilic, and chondroid calcifying masses surrounded with palisading histiocytes and foreign body-type giant cells. The findings were consistent with those of calcifying pseudotumors previously reported in other sites of the body. At 24 months after operation, a significant reduction of neck pain was achieved. But there was evidence of local recurrence of the lesion in the body and dens of the axis with a local progression of the preexisting lesion in the facet joints.

CONCLUSION

This is the first report of intraosseous calcifying pseudotumor arising from the axis.

Correction of arterial structure and endothelial dysfunction in human essential hypertension by the angiotensin receptor antagonist losartan

BACKGROUND

Structural and functional alterations of the vasculature may contribute to complications of hypertension. Because angiotensin II may be pivotal in some of these vascular abnormalities, we tested the hypothesis that the angiotensin type 1 (AT(1)) receptor antagonist losartan, in contrast to the beta-blocker atenolol, would correct resistance artery abnormalities in patients with essential hypertension.

METHODS AND RESULTS

Nineteen untreated patients with mild essential hypertension (47+/-2 years, range 30 to 65 years; 57% male) were randomly assigned in double-blind fashion to losartan or atenolol treatment for 1 year. Nine age/sex-matched normotensive subjects were also studied. Both treatments reduced blood pressure to a comparable degree (losartan, from 149+/-4.1/101+/-1.6 to 128+/-3.6/86+/-2.2 mm Hg, P<0.01; atenolol, from 150+/-4.0/99+/-1.2 to 130+/-3.2/84+/-1.4 mm Hg, P<0.01). Resistance arteries (luminal diameter 150 to 350 microm) dissected from gluteal subcutaneous biopsies were studied on a pressurized myograph. After 1 year of treatment, the ratio of the media width to lumen diameter of arteries from losartan-treated patients was significantly reduced (from 8.4+/-0.4% to 6.7+/-0.3%, P<0.01). Arteries from atenolol-treated patients exhibited no significant change (from 8. 3+/-0.3% to 8.8+/-0.5% after treatment). Endothelium-dependent relaxation (acetylcholine-induced) was normalized by losartan (from 82.1+/-4.9% to 94.7+/-1.1%, P<0.01) but not by atenolol (from 80. 4+/-2.7% to 81.7+/-4.6%). Endothelium-independent relaxation (by sodium nitroprusside) was unchanged after treatment.

CONCLUSIONS

The AT(1) antagonist losartan corrected the altered structure and endothelial dysfunction of resistance arteries from patients with essential hypertension, whereas the beta-blocker atenolol had no effect.

An in vitro assessment of the flow characteristics of spiral-ridged and smooth-walled JJ ureteric stents

OBJECTIVE

To assess drainage through spiral-ridged and smooth-walled JJ ureteric stents (designed to ensure upper tract drainage) and thus determine whether drainage preferentially occurs around rather than through the spiral-ridged stent, promoting renal flow and potentially facilitating the passage of urinary stone fragments. Materials and methods A mechanical ureteric model was constructed to mimic the funnel characteristics of the renal pelvis. A motor pump was used to help simulate respiratory and skeletal movement, resulting in differential motion between the intraluminal stent and the surrounding ureteric wall. Tubes of varying internal diameters were used to simulate different sizes of ureter. Flow rates of standard 7 F smooth-walled stents were compared with 7 F spiral-ridged stents with and without occluded lumens, and with and without standardized excursions.

RESULTS

Extraluminal flow (mean rates) with and without movements simulating respiratory excursions were significantly higher with the spiral stent for all stent diameters evaluated. All flow rates increased as the ureteric diameter increased. Total flow past the spiral stent was significantly greater than flow with the smooth-walled stent under all conditions tested. Flows measured around the spiral stent under conditions of excursion were the highest of all categories, 20-fold higher than in smooth-walled, closed, stationary stents.

CONCLUSION

Spiral-ridged JJ stents provided substantially greater flow in this in vitro model. Extraluminal flow was markedly increased with the spiral-ridged configuration. The difference in flow rates was more pronounced at the smaller pseudo-ureteric tube diameters, simulating dimensions found in clinical practice. The flow rate also was increased when the central lumen remained open, and was greater still when there was dynamic excursion with respiratory movements.

Synovial cyst of the transverse ligament of the atlas in a patient with os odontoideum and atlantoaxial instability

STUDY DESIGN

A case report and review of the literature.

OBJECTIVE

To describe the diagnosis and successful treatment of a synovial cyst arising from the transverse ligament in a patient with os odontoideum and atlantoaxial instability.

SUMMARY OF BACKGROUND DATA

Synovial cysts arising from the transverse ligament of the atlas are extremely rare. Development of a synovial cyst is thought to be attributable to degenerative changes of the C1-C2 facet joints or to microtrauma. Direct excision of the cyst is the only treatment cited in previous reports.

METHODS

A synovial cyst arising from the transverse ligament of the atlas in a 45-year-old man with os odontoideum and atlantoaxial instability was treated surgically with posterior atlantoaxial fusion alone. The magnetic resonance images, surgical treatment, and related literature are reviewed.

RESULTS

Preoperative magnetic resonance images of the cervical spine showed a large cystic mass located ventral to the cord arising at the level of the transverse ligament of the atlas: the mass was of low signal intensity on T1-weighted images, was of high signal intensity on T2-weighted images, and was enhanced marginally with gadolinium-DTPA on T1-weighted images. Spontaneous regression of the cyst was identified on the follow-up magnetic resonance images taken 3 months after C1-C2 posterior wiring and fusion.

CONCLUSIONS

A patient with a synovial cyst arising at the C1-C2 junction ventrally at the level of the transverse ligament showed spontaneous regression of the lesion after C1-C2 posterior wiring and fusion.

Reduction of resistance artery stiffness by treatment with the AT(1)-receptor antagonist losartan in essential hypertension

In spontaneously hypertensive rats resistance artery structure, endothelial dysfunction and geometry-independent wall stiffness were reduced by an angiotensin AT(1)-receptor antagonist. In previous studies of human hypertension, interruption of the renin-angiotensin system corrected small artery structure and endothelial dysfunction, whereas the beta-blocker atenolol did not. We hypothesized that the AT(1)R antagonist losartan, but not the beta-blocker atenolol, would reduce stiffness of gluteal subcutaneous small arteries in essential hypertensive patients. Seventeen untreated mild essential hypertensive patients (47+/-2 years; 75% male) were randomly assigned in double-blind fashion to losartan or atenolol treatment for one year. Small, resistance size arteries were studied on pressurized myographs. Blood pressure (mmHg) was reduced (p<0.01) from 145 +/- 4/101 +/- 2 and 147 +/- 6/98 +/- 2 to 128 +/- 4/86 +/- 2 and 131 +/- 3/84 +/- 1 by losartan and atenolol, respectively. The media/lumen ratio of small arteries was unaffected by atenolol (8.3+/-0.3% before and 8.8+/-0.5% after treatment). In contrast, losartan reduced media/lumen ratio from 8.4+/-0.4% to 6.7+/-0.3% (p<0.01). Whereas isobaric elastic modulus was unaffected by either treatment, geometry-independent stiffness (slope of elastic modulus vs. stress) was reduced from 9.7+/-1.2 to 6.1+/-0.9 (P<0.05) under losartan treatment, but was unchanged by atenolol (8.2+/-1.3 to 7.8+/-0.6). In conclusion, treatment with losartan reduced stiffness and structural alterations of subcutaneous resistance arteries of previously untreated essential hypertensive patients, whereas atenolol failed to do so.