Neuronal interactions are higher in the cortex than thalamus in the somatosensory pathway

Previous studies have shown significant correlated discharges (noise correlation) and synergistic information coding among adjacent cortical neurons. In order to investigate whether such interactions are present at an earlier stage of sensory processing, we compared noise correlation and synergistic information transmission in the ventral posterolateral nucleus (VPLn) of thalamus and primary somatosensory cortex (SI) of anesthetized rats. A hind paw was stimulated electrically and responses of several neighboring neurons were recorded simultaneously with a tetrode. Analyses indicated that noise correlation in the SI was about four times higher than in the VPLn, and, interestingly, it was significantly reduced following sensory stimulation in both regions. Spike count distributions of individual VPLn units contained higher amounts of information about the delivery of external stimulation compared with those of SI units. When simultaneously recorded units were considered together, transmission of information was more interactive (synergistic or redundant) among SI than VPLn units. On average, information transmission was independent in the VPLn, but synergistic in the SI. The difference in synergistic information coding was largely attributable to different levels of noise correlation and their modulation by external sensory stimulation. These results indicate that neuronal interactions are relatively low at the thalamic level, but much enhanced at the cortical level along the somatosensory pathway. The enhanced neuronal interactions in the cortex may reflect the role of cortex in extracting higher features of sensory stimuli.

Intramuscular neurilemoma

In this retrospective study, we analysed the clinical features of neurilemoma when it is located in muscle. Twelve patients had an intramuscular neurilemoma as shown on magnetic resonance (MR) scans and confirmed at operation. In six it was located in the upper limb, in five in the lower limb, and in one in the back. The mean age of the patients was 41 years (12 to 58). Nine complained only of a palpable mass and the other three of a mass with slight tenderness. None had neurological symptoms or signs, such as radicular pain, a positive Tinel sign, or motor weakness. There were no postoperative complications or recurrence of the tumour after a mean follow-up of two years (1 to 10).

Effect of glycolic acid on UVB-induced skin damage and inflammation in guinea pigs

OBJECTIVES

Recently the use of glycolic-acid-containing cosmetics has received increased public interest in their supposed ability to reduce wrinkles, roughness, age spots and other skin damage. However, the safety of such products when used excessively or chronically, especially by photosensitive people, is being questioned. The purpose of this study was to examine the effects of glycolic acid alone or in combination with UVB on skin damage and inflammatory response.

METHOD

Guinea pigs were treated with glycolic acid (from 1 to 7 mg/cm(2)) alone or in combination with UVB (0.4 or 3 J/cm(2)) for 14 days. Skin damage was evaluated by scoring the skin irritation value by the method of Draize and by histopathological observations. Cyclooxygenase 2 (COX-2) expression and prostaglandin E(2) (PGE(2)) production were also assessed.

RESULTS

Glycolic acid caused an increase in the level of skin damage in a dose- and time-dependent manner. Lower doses (1 and 3 mg/cm(2)) of glycolic acid mostly caused erythema and eschar, and these consequently formed scales, whereas higher doses (5 and 7 mg/cm(2)) of glycolic acid caused redness, edema and necrotic ulceration. Glycolic acid also increased the thickness of the epidermal layer, reduced the organization of the stratum corneum and eventually destroyed some parts of the epidermal layer at 7 mg/cm(2). UVB (0.4 and 3 J/cm(2)) caused redness and edema as well as reduced the integrity of the stratum corneum. Glycolic acid enhanced the UVB-induced skin damage. The magnitude of the damage caused by combined UVB and glycolic acid treatment was much greater than that caused by glycolic acid or UVB alone. Moreover, partial destruction of the epidermal layer was observed in skin treated with 3 J/cm(2) UVB and 3 mg/cm(2) glycolic acid. However, glycolic acid did not change the basal and UVB-induced PGE(2) production and COX-2 protein expression.

CONCLUSION

These results show that glycolic acid causes skin damage in a dose- and time-dependent manner and that it enhances UVB-induced skin damage without accompanying PGE(2) production or COX-2 protein expression. Therefore, caution should be exercised by those using glycolic acid on a chronic basis or excessively. Moreover, those with photosensitive skins and those more exposed to the sun should be particularly careful.

Combination Chemotherapy of Oxaliplatin, 5-Fluorouracil, and Leucovorin in 5-Fluorouracil-Pretreated Patients with Metastatic Colorectal Cancer

PURPOSE

To evaluate the efficacy and toxicity of oxaliplatin in combination with 5-fluorouracil (5-FU) and leucovorin (LV) in patients with metastatic colorectal cancer who previously treated with 5-FU-based chemotherapy.

MATERIALS AND METHODS

Between April 1999 and January 2001, thirty-two patients were enrolled in this study. Oxaliplatin 130 mg/m2 was given intravenously (IV) on day 1 as was 5-FU 500 mg/m2 IV followed by continuous infusion of 5-FU 3,000 mg/m2 and LV 100 mg/m2 for 48 hours administered every 3 weeks. Six patients had received 5-FU as an adjuvant setting and 26 patients as a palliative regimen.

RESULTS

The median age of the patients was 50 years (range; 19-69) and the dominant sites of metastasis were the liver, lung or both in 9, 5 and 2 patients respectively. In 30 evaluable patients, the overall response rate was 27% including 1 complete response and 7 partial responses. The median response duration was 28 weeks (95% confidence interval; 22~34 weeks) and the median progression free survival of all patients was 24 weeks (95% confidence interval; 15~33 weeks). A median 5 cycles (range; 2~9) and total 155 cycles were performed in 32 patients. 150 cycles were evaluable for toxicity. The most common hematologic toxicity was grade 1~2 anemia in 78 cycles (52%). Leukopenia (39%) and thrombocytopenia (23%) were fully reversible. The most common non-hematologic toxicity was nausea/vomiting (43/30%) followed by diarrhea (23%), hepatotoxicity (21%) and neurotoxicity (21%). One patient ceased therapy due to grade 4 diarrhea. No other severe toxicity interrupted this treatment.

CONCLUSION

Oxaliplatin, 5-FU and LV in combination showed significant activity in previously treated metastatic colorectal cancer with favorable toxicity.

Anastomosis of vessels less than 2 mm with the vascular clip system clip applier

Sutures may cause endothelial trauma and occlusion. The vascular clip system (VCS) clip applier may minimize endothelial injury. Fourteen carotid arteries of nine adult rabbits were transected and re-anastomosed with either #7-0 polypropylene (Group I, n=8) or VCS clips (Group II, n=6). The animals were sacrificed at 1, 3, 8, 14, and 30 days postoperatively. The operation time and bleeding amount were checked for each anastomosis. Carotid angiograms, photography, H&E staining and scanning electron microscopy (SEM) were performed. Fibrin and thrombus, inflammatory cell infiltration, endothelial disruption, luminal distortion, fibrosis, and wall thickening were compared. The luminal diameter was greater in group II. There were minimal differences in thrombosis, wall thickening and fibrosis between the two groups. However, fibrin, inflammatory cell infiltration, multinucleated giant cell formation, endothelial disruption, and luminal distortion were greater in group I. On SEM, group I showed trans-mural penetration. In contrast, group II showed suture margin eversion and no transmural penetration. Stenosis was greater in group I than in group II on carotid angiogram. The operation time was shorter in group II than in group I, i.e. 5+/-1.4 min vs. 11+/-3.8 min, respectively. The current data showed similar or superior results with VCS clips in comparison to conventional suturing with polypropylene.

Fra-1 expression in malignant and benign thyroid tumor

BACKGROUND

The differential diagnosis of thyroid nodules is very important in deciding the treatment modality and the fine needle aspiration is the best diagnostic method. But, there are some limitations in use because of inadequate test materials and difficulty in interpreting. According to the study of oncogene and tumor suppressor gene about the origin of thyroid tumor, expression of Fra-1, one of AP-1 complex, is increased in thyroid neoplasm, though not present in the normal tissue. So, there is a possibility that it will be used as a method for the differential diagnosis of thyroid nodules. We tried to know whether presence or absence of Fra-1 expression can be used as a diagnostic method in differential diagnosis of thyroid nodules using the immunohistochemical (IHC) staining method.

METHODS

In 4 types of thyroid tumor that were confirmed by histologic diagnosis after operation (18 cases of adenomatous goiter, 16 cases of follicular adenoma, 30 cases of papillary cancer, 10 cases of follicular cancer), IHC staining method was performed to evaluate the expression of Fra-1.

RESULTS

In papillary and follicular thyroid cancers, the expression of Fra-1 was stronger than in benign thyroid tumor, but there was no difference in Fra-1 expression between the two types of carcinoma. Weak expression of Fra-1 was observed in all cases of follicular adenoma, though it was weaker than in carcinoma, and it was also weakly expressed only in some cases (33%) of adenomatous goiter.

CONCLUSION

The expression of Fra-1 was stronger in thyroid cancer than in benign thyroid tumor, but it was impossible to differentiate thyroid cancer from benign thyroid tumor by presence or absence of Fra-1 expression using IHC staining method.

Structural and functional alterations of the peritoneum after prolonged exposure to dialysis solutions: role of aminoguanidine

OBJECTIVE

The effect of long-term use of high glucose dialysate on peritoneal structure and function, and its relation with accumulation of advanced glycosylation end-product (AGE) in the peritoneum was investigated in this study.

METHODS

Dialysates with 4.25% glucose were injected into the peritoneal cavity of normal rats for 12 weeks without (PD, n = 7) and with (1 g/L, PD+AG, n = 7) aminoguanidine in their drinking water. Rats not having intraperitoneal (IP) injection served as control (n = 9). After 12 weeks of IP injection, a 2-hour peritoneal equilibration test (PET) was performed using 30 mL 4.25% glucose dialysate. Intraperitoneal volume (IPV), dialysate-to-plasma urea ratio at 2 hours (D/P2), the ratio of dialysate glucose at 2 hours to initial dialysate glucose (D2/D0), and the peritoneal fluid absorption rate (Qa) were evaluated. After the PET, samples of the parietal peritoneum were taken for hematoxylin and eosin (H&E) staining and immunohistochemical staining for AGE.

RESULTS

The IPV and D2/D0 glucose were significantly lower and Qa and D2/P2 urea significantly higher in the PD group than in the control group. Aminoguanidine reversed in part the changes in IPV and D2/P2 urea in the PD group; it had no effect on Qa and D2/D0 glucose. The H&E staining showed a linear mesothelial lining with negligible cells and capillaries in the narrow submesothelial space in the control group. Mesothelial denudation and submesothelial infiltration of monocytes and capillary formation were observed in the PD group. Mesothelial denudation was relatively intact in the PD+AG group compared with the PD group. Submesothelial monocyte infiltration and capillary formation in the PD+AG group were not as prominent as in the PD group. Positive AGE staining was found in the submesothelial space, vascular walls, and endomysium in the PD group, while it was markedly attenuated in PD+AG group and negligible in the control group.

CONCLUSION

Long-term use of high glucose solutions induced peritoneal AGE accumulation and mesothelial denudation, and increased peritoneal permeability and peritoneal fluid absorption rate. Inhibition of peritoneal AGE accumulation prevented those functional and structural damages to the peritoneum.

Radiologic anatomy of the rabbit liver on hepatic venography, arteriography, portography, and cholangiography

Seo TS, Oh JH, Lee DH, et al. Radiologic anatomy of the rabbit liver on hepatic venography, arteriography, portography, and cholangiography. Invest Radiol 2001;36:186-192.

RATIONALE AND OBJECTIVES

The radiologic anatomy of rabbit liver has received little study but is important in many experimental investigations.

METHODS

Twenty-four rabbits were studied by using hepatic venograms, aortograms, hepatic arteriograms, cholangiograms, and portograms.

RESULTS

In all cases, the right, middle, and left hepatic veins drained into the inferior vena cava just below the diaphragm, and the caudate lobe hepatic vein drained more inferiorly. The proper hepatic artery was a branch of the common hepatic artery in 96%. The first branch of the proper hepatic artery was the caudate lobe artery. The remaining main hepatic artery was divided into the right and left hepatic arteries. The left hepatic artery was further divided into the medial and lateral segmental branches in 95%. The anatomy of the portal vein or bile duct was the same as the hepatic artery in 100% of cases.

CONCLUSIONS

Knowledge of the normal patterns and variations of the vessels and bile duct will be helpful for experiments of the rabbit liver in future studies.

Presacral epidermoid cyst: imaging findings with histopathologic correlation

BACKGROUND

The aim of this study was to determine the imaging characteristics of presacral epidermoid cysts and correlate the imaging findings with the histopathologic findings.

METHODS

We retrospectively reviewed sonographic, computed tomographic, and magnetic resonance examinations in four consecutive patients with a pathologically proven presacral epidermoid cyst. Imaging findings of the presacral epidermoid cyst were correlated with the histopathologic findings.

RESULTS

In all four patients, sonography showed a presacral mass with a heterogeneous low echogenicity, and computed tomography showed a discrete well-defined hypodense presacral mass with a thin wall. In the three patients who underwent magnetic resonance imaging, the mass showed a heterogeneous low signal intensity on the T1-weighted image and a high signal intensity with multiple small foci of low signal intensity in the nondependent portion of the mass on the T2-weighted image. These imaging findings correlated well with the pathologic results. Aggregates of keratinous material contributed to these imaging findings.

CONCLUSION

In the diagnosis of the presacral epidermoid cyst, sonographic and magnetic resonance imaging findings may be helpful.

Percutaneous endovascular stent-graft for iliac pseudoaneurysm following lumbar discectomy

In a 24-year-old woman, an iliac pseudoaneurysm following lumbar discectomy was successfully treated by percutaneous placement of a self-expanding stent-graft. A postprocedural angiogram demonstrated complete exclusion of the pseudoaneurysm without leakage of contrast agent.

Bone bruises: MR characteristics and histological correlation in the young pig

PURPOSE

To correlate magnetic resonance (MR) signal characteristics of bone bruises with histological findings.

MATERIALS AND METHODS

In 14 tibiae of young pigs, bone bruises were created in the proximal tibial metaphysis. The signal intensity seen on the MR images were correlated with histological findings. The following findings were evaluated: (a) changes of signal intensity on the tibiae; (b) changes of histology on the tibiae; and (c) changes of (a) and (b) on follow-up examinations.

RESULTS

We observed three types of injuries on T1-weighted images: focal or diffuse low signal, normal signal and linear low signal intensities. Severe hemorrhagic areas showed low signal intensities on all sequences of MR imaging. Fast spin-echo (FSE) T2-weighted images showed a more distinct low signal intensity than T1-weighted images. FSE short tau inversion recovery (STIR) and FSE fat saturated (FSE-FS) T2-weighted images showed similar signal intensities with FSE T2-weighted images. FS T1-weighted enhanced images showed low signal intensities with variable enhancements. Upon histological examination, hemorrhages and edemas were prominent at the subcortical areas of the contusion sites. The areas of dense, low signal intensities in all imaging sequences showed signs of severe hemorrhage. The areas of diffuse low signal and enhanced areas showed mixed areas of hemorrhages and edemas. Follow-up MR imaging showed evolution of the processes of hemorrhages and edemas with fatty marrow changes.

CONCLUSIONS

MR imaging can depict changes in the bone marrow resulting from direct injury to the bone. MR imaging is a useful tool for evaluating the evolution of bone bruises.

Treatment of suprachoroidal hemorrhage with tissue plasminogen activator

We evaluated the efficacy of tissue plasminogen activator in treating experimental suprachoroidal hemorrhage. Suprachoroidal hemorrhage was created in 30 white rabbit eyes by implanting four pieces of small, exogenously formed blood coagula into the suprachoroidal space. Animals were randomized for treatment with a surgical sponge soaked in 25, 50, or 75 microg of tissue plasminogen activator (tPA) or balanced salt solution (BSS) as a control. The time when initiation and completion of clot dissolution occurred was established, and histological examination was performed to assess damage. Clot dissolution started within 30 min in the 50- and 75-microg tPA group, whereas it took 2.75 days in the control group; complete dissolution of blood clots took 4.5 h in the 75-microg tPA group and 14 days in the control group. Histological examination revealed a minimal change in photoreceptors within 6 h after treatment with 75 microg tPA. Treatment of suprachoroidal hemorrhage with tPA seems to be effective, but further investigations for determining the effective and nontoxic dose are required.

Treatment of prostatic abscess: value of transrectal ultrasonographically guided needle aspiration

The purpose of this study was to assess the effectiveness of transrectal ultrasonographically guided needle aspiration in the treatment of prostatic abscess. Fourteen patients with prostatic abscess were evaluated with this technique and treated with sonographically guided needle aspiration. Using this technique, all cases (100%) had one or more hypoechoic areas within the prostate that contained inhomogeneous materials; in 10 patients (71.0%), the lesion showed internal septa or solid portion. The margins of the hypoechoic area were well defined and thick in 11 patients (79.0%) and poorly defined in 3 patients (21.0%). The estimated volume of the prostatic abscess ranged between 2 and 28 ml (mean, 12.0 ml). The presence of a pus collection within the prostate was confirmed by transrectal ultrasonographically guided aspiration in all patients. However, successful treatment of prostatic abscess with transrectal needle aspiration was done in 12 (86.0%) of 14 patients; the treatment failed in 2 (14.0%) of 14 patients. One patient was treated with perineal incision and drainage and the other with transurethral resection. The amount of pus drained ranged between 1 and 39 ml (mean, 12.0 ml). On follow-up transrectal ultrasonographic examination, no remaining abscess pocket was found within the prostate in any of the cases. One year later, the prostatic abscess recurred in one case. In conclusion, transrectal ultrasonographic guidance is useful in the diagnosis of prostatic abscess as well as in the guidance for aspiration and the drainage of such abscesses. Transrectal ultrasonographically guided needle aspiration could be an effective method for treating prostatic abscess.

Ultra-rapid freezing of human multipronuclear zygotes using electron microscope grids

Developmental capacity of human multipronuclear (PN) zygotes cryopreserved using an ultra-rapid freezing method and electron microscope (EM) grids was studied. Multipronuclear zygotes obtained from a human IVF programme were used as an alternative to normal 2PN zygotes; they were divided into 3PN or >or =4PN zygotes and their in-vitro development and cryo-injury were compared according to PN number. EFS30, which consisted of 30% ethylene glycol, 18% Ficoll, 0. 5 mol/l sucrose and 10% fetal bovine serum with added modified Dulbecco's phosphate buffered saline was used as the freezing solution. After ultra-rapid freezing and thawing 85.5% of multipronuclear zygotes survived. A comparison of cleavage rates between the control and cryopreserved groups showed no significant difference (3PN; 81.3 and 85.4% and > or =4PN; 90.0 and 95.7% respectively). Comparing the in-vitro development after thawing up to blastocyst formation on day 5 after IVF, the outcome of the frozen 3PN group (22.0%) was not different from that of control 3PN group (38.5%), while the outcome of the frozen > or =4PN group (4.5%) was significantly lower than that of control > or =4PN group (44.4%) (P < 0.05).

Serum ferritin in healthy subjects and type 2 diabetic patients

In order to study the relationship between the serum ferritin level and the components of the insulin resistance syndrome in type 2 diabetic patients, we evaluated fifty type 2 diabetic patients who were selected according to NDDG/WHO criteria from those patients attending Korea University Hospital from 1997 to 1998. Twenty-five healthy non-diabetic subjects of comparable age and sex distribution acted as a control group. The results showed that the value of log ferritin was higher in the type 2 diabetes patients than the control subjects, but not at a statistically significant level (p = 0.09). Log ferritin was correlated with fasting blood sugar level (r = 0.235, p = 0.048) and body mass index (BMI) (r = 0.285, p = 0.05). In the type 2 diabetic patients, log ferritin was correlated with fasting C-peptide (r = 0.478, p = 0.009). In the control subjects, log ferritin was correlated only with BMI (r = 0.477, p = 0.012). In a stepwise multiple regression analysis, the diabetic group showed a significant correlation between fasting C-peptide and log ferritin (p = 0.001). In the control group, the fasting sugar level was significantly correlated with log ferritin (p = 0.034). These results suggest that serum ferritin can be employed as a marker of not only glucose homeostasis but also insulin resistance both in type 2 diabetic and control subjects.

Acetic acid as a sclerosing agent for renal cysts: comparison with ethanol in follow-up results

PURPOSE

To compare follow-up results of sclerotherapy for renal cyst using 50% acetic acid with those using 99% ethanol as sclerosing agents.

METHODS

Eighty-one patients underwent sclerotherapy and 58 patients, 23 males, 35 females, aged 6-76 years, having a total of 60 cysts, were included in this study; the others were lost to follow-up. The renal cysts were diagnosed by sonography, computed tomography (CT), or magnetic resonance imaging (MRI). Sclerotherapy was performed using 50% acetic acid for 32 cysts in 31 patients and 99% ethanol for 28 cysts in 27 patients. Under fluoroscopic guidance, cystic fluid was aspirated as completely as possible. After instillation of a sclerosing agent corresponding to 11.7%-25% (4-100 ml) of the aspirated volume, the patient changed position for 20 min and then the agent was removed. Patients were followed up by sonography for a period of 1-49 months. The volume of the renal cyst after sclerotherapy was compared with that of the renal cyst calculated before sclerotherapy. Medical records were reviewed to analyze complications.

RESULTS

The mean volume after sclerotherapy of the 17 cysts followed for 3-4 months in the acetic acid group was 5.1% of the initial volume, and for the 14 cysts in the ethanol group it was 10.2%. Complete regression during follow-up was shown in 21 cysts (66%) in the acetic acid group; the mean volume of these cysts before the procedure was 245 ml. The mean volume of the nine (32%) completely regressed cysts in the ethanol group was 184 ml. Mild flank pain, which occurred in three patients in each group, was the only complication and resolved the next day.

CONCLUSION

Acetic acid was an effective and safe sclerosing agent for renal cysts, tending to induce faster and more complete regression than ethanol.

Ginsenoside RH-2 induces apoptotic cell death in rat C6 glioma via a reactive oxygen- and caspase-dependent but Bcl-X(L)-independent pathway

We used the rat C6 gliomal cell line to investigate the potential role of ginsenoside Rh2 (G-Rh2) in brain tumor. G-Rh2 induced many apoptotic manifestations in C6 gliomal cells as evidenced by changes in cell morphology, generation of DNA fragmentation, activation of caspase and production of reactive oxygen species (ROS). As a result, cotreatment with antioxidants or a broad-spectrum caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone effectively attenuated G-Rh2-induced cell death. However, specific cleavage of poly(ADP-ribose)polymerase into 85 kDa protein was not detected as demonstrated in many other apoptotic paradigms. Expression levels of Bcl-2 and Bax remained unchanged following G-Rh2 treatment. Furthermore, G-Rh2-induced cell death in C6 gliomal cells overexpressing antiapoptotic protein, Bcl-X(L), was comparable to that in parental cells. Taken together, our data indicate that G-Rh2-induced cell death is mediated by the generated ROS and the activation of caspase pathway in a Bcl-X(L)-independent manner.

Effect of eradication of Helicobacter pylori on the benign gastric ulcer recurrence--a 24 month follow-up study

OBJECTIVES

To evaluate the effect of eradication of Helicobacter pylori (H. pylori) on the recurrence of benign gastric ulcer (BGU) in the patients with BGU.

METHODS

This study was performed for 40 H. pylori-positive BGU patients cured of BGU and H. pylori eradicated, and for 25 H. pylori-positive patients (non-eradicated group) who were not treated with H. pylori eradication regimen or H. pylori was not eradicated. Four different methods--CLOtest, microscopy of Gram stained mucosal smear, culture and histology of modified Giemsa staining--were taken for identifying colonization of H. pylori before treatment, and 4 weeks after completion of triple therapy. For the control group in which triple therapy was not tried, follow-up gastroscopy was done to confirm the healing of the ulcer. To detect BGU recurrence, the gastroscopy was performed at 6, 12, 18, and 24 months after therapy.

RESULTS

In the non-eradicated group, the BGU recurrence rate was 16% within 6 months, 40% within 1 year, 56% within 18 months and 60% within 2 years. The respective recurrence rates in the 40 patients in whom the bacteria had been eradicated were 0%, 7.5%, 10% and 10% (4 patients), respectively. Among the four BGU-recurred patients in whom H. pylori had been eradicated, one patient was found to have BGU recurring with H. pylori positive again in one year, and another two patients had NSAIDs ingestion history.

CONCLUSION

The eradication of H. pylori in patients with BGU reduces the recurrence of BGU. In addition, the major causes of BGU recurrence look like NSAIDs ingestion and reinfection of H. pylori.

Establishment and characterization of 12 human colorectal-carcinoma cell lines

In this article, we describe the characteristics of 12 human colorectal-carcinoma cell lines established from 6 primary tumors and 6 metastatic sites of 11 Korean colorectal-carcinoma patients, including the morphology in vivo and in vitro and mutations of K-ras2, p15, p16, p53, APC, beta-catenin, hMLH1 and hMSH2 genes in vitro. No lines were contaminated with Mycoplasma or bacteria. All lines were proven to be unique by DNA-fingerprinting analysis. All lines expressed the surface carcino-embryonic antigen and secreted it into the supernatant fluid. The morphological correlation between the original tumors and cultured cells suggested that the original tumors showing mucinous adenocarcinoma correlated with floating aggregates in culture, and degree of desmoplasia in the original tumor correlated with attached growth in culture. Five of the cell lines showed mutations in the K-ras2 gene, and 6 of the cell lines showed mutations in the p53 gene. The p15 gene was deleted in 2 cell lines, and the p16 gene was hypermethylated in 3 cell lines. The mutation of mismatch-repair genes (hMLH1 and hMSH2) was found in 4 lines, the APC gene and beta-catenin gene were mutated in 9 and 2 lines respectively. These well-characterized colorectal-cancer cell lines should serve as useful tools for investigating the biological characteristics of colorectal cancer.

Establishment and characterization of 12 human colorectal-carcinoma cell lines

In this article, we describe the characteristics of 12 human colorectal-carcinoma cell lines established from 6 primary tumors and 6 metastatic sites of 11 Korean colorectal-carcinoma patients, including the morphology in vivo and in vitro and mutations of K-ras2, p15, p16, p53, APC, beta-catenin, hMLH1 and hMSH2 genes in vitro. No lines were contaminated with Mycoplasma or bacteria. All lines were proven to be unique by DNA-fingerprinting analysis. All lines expressed the surface carcino-embryonic antigen and secreted it into the supernatant fluid. The morphological correlation between the original tumors and cultured cells suggested that the original tumors showing mucinous adenocarcinoma correlated with floating aggregates in culture, and degree of desmoplasia in the original tumor correlated with attached growth in culture. Five of the cell lines showed mutations in the K-ras2 gene, and 6 of the cell lines showed mutations in the p53 gene. The p15 gene was deleted in 2 cell lines, and the p16 gene was hypermethylated in 3 cell lines. The mutation of mismatch-repair genes (hMLH1 and hMSH2) was found in 4 lines, the APC gene and beta-catenin gene were mutated in 9 and 2 lines respectively. These well-characterized colorectal-cancer cell lines should serve as useful tools for investigating the biological characteristics of colorectal cancer.

Sequential cleavage of poly(ADP-ribose)polymerase and appearance of a small Bax-immunoreactive protein are blocked by Bcl-X(L) and caspase inhibitors during staurosporine-induced dopaminergic neuronal apoptosis

To assess the role of Bcl-X(L) and its splice derivative, Bcl-X(S), in staurosporine-induced cell death, we used a dopaminergic cell line, MN9D, transfected with bcl-xL (MN9D/Bcl-X(L)), bcl-xS (MN9D/Bcl-X(S)), or control vector (MN9D/Neo). Only 8.6% of MN9D/Neo cells survived after 24 h of 1 microM staurosporine treatment. Caspase activity was implicated because a caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-fmk), attenuated staurosporine-induced cell death. Bcl-X(L) rescued MN9D cells from death (89.4% viable cells), whereas Bcl-X(S) had little or no effect. Bcl-X(L) prevented morphologically apoptotic changes as well as cleavage of poly(ADP-ribose)polymerase (PARP) induced by staurosporine. It is interesting that a small Bax-immunoreactive protein appeared 4-8 h after PARP cleavage in MN9D/Neo cells. The appearance of the small Bax-immunoreactive protein, however, may be cell type-specific as it was not observed in PC12 cells after staurosporine treatment. The sequential cleavage of PARP and the appearance of the small Bax-immunoreactive protein in MN9D cells were blocked either by Z-VAD-fmk or by Bcl-X(L). Thus, our present study suggests that Bcl-X(L) but not Bcl-X(S) prevents staurosporine-induced apoptosis by inhibiting the caspase activation that may be directly or indirectly responsible for the appearance of the small Bax-immunoreactive protein in some types of neurons.

Do symptoms predict cardiac arrhythmias and mortality in patients with syncope?

BACKGROUND

Patients with syncope frequently present with multitude of other symptoms but their significance in predicting morbidity or mortality has not been previously studied.

OBJECTIVE

To determine if certain symptoms can be used to identify syncope patients at risk for cardiac arrhythmias, mortality, or recurrence of syncope.

PATIENTS AND METHODS

From August 1987 to February 1991, we prospectively evaluated patients with syncope from outpatient, inpatient, and emergency department services of a university medical center. These patients were interviewed, charts were reviewed, and detailed information on 19 symptoms and comorbidities was obtained. A cause of syncope was assigned using standardized diagnostic criteria. All patients were followed up at 3-month intervals for at least 1 year for recurrence of syncope and mortality. Patients in whom the cause of syncope was determined by medical history and physical examination alone were not included in our analysis.

RESULTS

History and physical examination led to the cause of syncope in 222 of 497 patients enrolled. In the remaining 275 patients, the absence of nausea and vomiting before syncope (odds ratio, 7.1) and electrocardiographic abnormalities (odds ratio, 23.5) were predictors of arrhythmic syncope. Underlying cardiac disease was the only predictor of 1-year mortality. No symptom remained as independent predictor for 1-year mortality or syncope recurrence.

CONCLUSIONS

Symptoms, although important in assigning many noncardiac causes, are not useful in risk-stratifying patients whose cause of syncope cannot be identified by other history and physical examination. Triage decisions and management plans should be based on pre-existing cardiac disease or electrocardiographic abnormalities, which are important predictors of arrhythmic syncope and mortality.

Screening of Korean forest plants for rat lens aldose reductase inhibition

Naturally occurring substances which can prevent and treat diabetic complications were sought by examining ethanol extracts prepared from Korean forest plants for their inhibitory effects on rat lens aldose reductase activity in vitro. Among the plants examined, Acer ginnala, Illicium religiosum and Cornus macrophylla exerted the most strong inhibitory activity on aldose reductase.

Sequential effects of high glucose on mesangial cell transforming growth factor-beta 1 and fibronectin synthesis

BACKGROUND

Transforming growth factor (TGF)-beta is recognized as the final common mediator of the principal lesions of diabetic nephropathy such as renal hypertrophy and mesangial expansion. To gain better understanding of the temporal relationships between high glucose (HG) and mesangial cell (MC) TGF-beta 1 synthesis and between TGF-beta 1 and extracellular matrix (ECM) synthesis, the present study examined early and sequential effects of HG on TGF-beta 1 and fibronectin (FN) mRNA expression and protein synthesis.

METHODS

Confluent primary rat MC was stimulated with 5.6 (control) or 30 (high) mM glucose after synchronizing the growth by incubation with serum-free media for 48 hours.

RESULTS

Mesangial cell TGF-beta 1 mRNA expression increased significantly in six hours and continued to increase until 48 hours in response to HG. The level of TGF-beta 1 mRNA was 1.5-fold higher than that of control glucose at six hours and 1.8-fold at 48 hours. TGF-beta activity in heat-activated conditioned media under HG increased 1.5- and 1.6-fold at 24 and 48 hours, respectively, compared to control glucose. FN mRNA increased significantly at 24 and 48 hours and 1.4-fold that of control glucose at both time points. FN protein also increased 1.5-fold that of control glucose at 48 hours. Anti-TGF-beta antibody completely abolished HG-induced FN synthesis.

CONCLUSIONS

The present finding demonstrate that HG stimulates TGF-beta 1 very early and prior to FN production and that HG-induced FN production is mediated by TGF-beta. This finding is consistent with the view that TGF-beta mediates increased ECM accumulation by MC under high glucose conditions.

Overexpression of HA-Bax but not Bcl-2 or Bcl-XL attenuates 6-hydroxydopamine-induced neuronal apoptosis

Bax, a member of the Bcl-2 gene family, is known to promote apoptosis in many cases but to block cell death under certain conditions. To investigate the potential role of Bax in 6-hydroxydopamine (6-OHDA)-induced cell death, we first established and characterized a dopaminergic neuronal cell line (MN9D) stably overexpressing hemagglutinin epitope-tagged Bax (MN9D/HA-Bax) as well as control clones (MN9D/Neo). Treatment of MN9D/Neo cells with 6-OHDA induced typical apoptotic cell death accompanied by shrinkage of the cell, nuclear condensation, and DNA fragmentation as demonstrated by light microscopy and agarose gel analysis. Overexpression of HA-Bax in MN9D cells was shown to attenuate 6-OHDA-induced cell death as determined by the MTT reduction assay and agarose gel analysis for DNA fragmentation. Western blot analysis revealed that cleavage of poly(ADP-ribose)polymerase induced by 6-OHDA was attenuated in MN9D/HA-Bax cells. In contrast, overexpression of a well-known cell death-inhibiting protein such as Bcl-2 or Bcl-XL did not attenuate 6-OHDA-induced cell death. Interestingly, cell death induced by hydrogen peroxide (0.25-2.0 mM) was significantly accelerated, whereas the rate of cell death induced by menadione (10-50 microM) was not affected in MN9D/HA-Bax cells. Thus, our present data suggest that the functionally diverse roles of Bax may be determined by the type of stress applied to the cell.

Antihypertensive effects of the novel potassium channel activator SKP-450 and its major metabolites in rats

Antihypertensive effects of SKP-450 (KR-30450, CAS 172489-10-0, (-)-(2R)-2"-(1",3"-dioxolan-2-yl)-2-2methyl-4-(2'-oxopyrr olidin-1-yl)-6- nitro-2H-1-benzopyran), a newly synthesized potassium channel activator, and its major metabolites SKP-818 ((-)-(2R)-2"-hydroxymethyl-2-methyl-4-(2'-oxopyrrolidin-1-yl)-6-ni tro- 2H-1-benzopyran) and SKP-310 ((-)-(2R)-2"-carboxy-2-methyl-4-(2'-oxopyrrolidin-1-yl)-6-nitro-2H -1- benzopyran) were evaluated in freely moving spontaneously hypertensive (SHR), renally hypertenisve (RHR), DOCA/salt-induced hypertensive (DHR) and normotensive rats (NR). The effects of long-term treatment with SKP-450 on blood pressure and arterial reactivity were also studied in SHR. SKP-450 (3-300 micrograms/kg, p.o.) and SKP-818 (3-100 micrograms/kg, i.v.) dose-dependently decreased mean arterial pressure (MAP) (potency order: SKP-450, RHR > SHR = DHR > NR; SKP-818, DHR = SHR = RHR > NR); however, SKP-310 did not influence MAP. Compared with lemakalim, SKP-450 was 2 to 5 fold more potent in SHR and NR, and equipotent in RHR and DHR. Repeatedly administration of SKP-450 to SHR over 21 days (10 and 30 micrograms/kg, p.o., once a day), had no significant effect on the degree and pattern of its antihypertensive effects and on the reactivity of isolated aorta to various vasoconstrictors and vasodilators. These results suggest that SKP-450 is a potent peripheral vasodilator acting without the development of tolerance and the alteration in vascular reactivity. SKP-818 and SKP-310 may play a role as an active metabolite and inactive intermediary, respectively.

The effects of prosthetic cardiac binding and adynamic cardiomyoplasty in a model of dilated cardiomyopathy

OBJECTIVE

Because adynamic cardiomyoplasty, or wrapping skeletal muscle around the heart, had been shown to provide a girdling effect and delay progressive ventricular dilatation in heart failure, a similar girdling effect by the much simpler procedure of cardiac binding, using a prosthetic membrane to wrap the heart, was studied and compared with that of adynamic cardiomyoplasty.

METHODS

Twenty-one dogs were divided into control, adynamic cardiomyoplasty, and cardiac binding groups. Cardiac dimension and hemodynamic studies were carried out before and 4 weeks after rapid pacing at 250 beats/min. For adynamic cardiomyoplasty, the left latissimus dorsi muscle was used for the cardiac wrap; for cardiac binding, a Marlex sheet (C. R. Bard, Inc., Murray Hill, N.J.) was used. Serial two-dimensional echocardiography, right heart catheterization, and in the cardiac binding group, left heart catheterization were performed.

RESULTS

Four weeks of rapid pacing induced severe heart failure and cardiac dilatation. The magnitude of ventricular dilatation at the end of rapid pacing was less in the cardiac binding group than in the control group and least in the adynamic cardiomyoplasty group. Left ventricular end-diastolic volume, end-systolic volume, and ejection fraction were 82.1 +/- 21.1 ml, 67.1 +/- 16.0 ml, and 17.5% +/- 5.8%, respectively, in the control group; 61.9. +/- 8.1 ml, 44.1 +/- 7.8 ml, and 30.1% +/- 3.6%, respectively, in the cardiac binding group; and 51.8 +/- 8.7 ml, 30.3 +/- 10.4 ml, and 27.0% +/- 4.0%, respectively, in the adynamic cardiomyoplasty group.

CONCLUSIONS

Both adynamic cardiomyoplasty and cardiac binding reduced cardiac enlargement and functional deterioration after rapid pacing, with adynamic cardiomyoplasty appearing to be more effective, perhaps because of the adaptive capabilities of the skeletal muscle wrap. However, cardiac binding is a simpler and less invasive procedure, which may be useful as an adjunct to prevent or delay progressive ventricular dilatation in heart failure.

Analysis of the gene encoding cyclomaltodextrinase from alkalophilic Bacillus sp. I-5 and characterization of enzymatic properties

The gene encoding cyclomaltodextrinase (CDase) was cloned from alkalophilic Bacillus sp. I-5. The nucleotide sequence of the gene was determined and the physicochemical properties of the enzyme were investigated. The gene had an open reading frame of 559 amino acids with a predicted molecular weight of 64,884. The enzyme was purified to near homogeneity from Escherichia coli cells carrying a recombinant plasmid that contained the CDase gene. The enzyme hydrolyzed cyclomaltoheptaose (beta-CD) 13 times better than starch and 33 times better than pullulan, and it had transglycosylation activity. The enzyme also hydrolyzed acarbose, a pseudotetrasaccharide inhibitor of glucosidases. The enzyme was stabilized by Ca2+ and the activity was increased more than twofold in the presence of 5 mM EDTA. The optimum temperature of the enzyme was elevated from 40 to 50 degrees C by Ca2+ ion and the thermal activity was maintained more than 80% at 60 degrees C in the presence of Ca2+. Comparison of known amino acid sequences of several amylolytic enzymes with cyclomaltodextrinase activity, site-directed mutagenesis of the enzyme, and substrate specificity of the enzyme imply that the region between the third and the fourth conserved regions of the enzyme may play an important role in binding and degradation of cyclomaltodextrin.

Mechanisms of cardiomyoplasty: comparative effects of adynamic versus dynamic cardiomyoplasty

BACKGROUND

The apparent paradox seen in patients who have undergone dynamic cardiomyoplasty and shown substantial clinical and functional improvements with only modest hemodynamic changes may be due to inappropriate end points chosen for study, a result of incomplete understanding of mechanisms involved. The purpose of this study was to compare the relative role of the passive "girdling effect" and the dynamic "systolic squeezing effect" of the wrapped muscle in cardiomyoplasty.

METHODS

The control group of 6 dogs underwent 4 weeks of rapid pacing (250 beats/min) to induce severe heart failure followed by 8 weeks of observation without rapid pacing. The trajectory of recovery in hemodynamics and cardiac dimensions was followed with echocardiography and Swan-Ganz catheters. In the "adynamic" cardiomyoplasty group (n=4), the left latissimus dorsi muscle was wrapped around the ventricles and allowed to stabilize and mature for 4 weeks. This was followed by rapid pacing and recovery as in the control group. In the "dynamic" cardiomyoplasty group (n=3), the same protocol for the adynamic group was followed except that a synchronizable cardiomyostimulator was attached to the thoracodorsal nerve of the muscle wrap. This allowed the latter to be transformed during the rapid-pacing phase and permitted dynamic squeezing of the muscle wrap to be generated by burst stimulation synchronized with cardiac contraction in a 1:2 ratio.

RESULTS

Baseline data were comparable in all groups prior to rapid pacing. After 4 weeks of rapid pacing, the left ventricular ejection fraction was higher in the adynamic (27.0%+/-3.9%; p < 0.05) and dynamic (33.3%+/-2.3%; p < 0.02) cardiomyoplasty groups compared with controls (18.8%+/-8.3%). Similarly, ventricular dilatation in both systole and diastole was less in the adynamic (51.8+/-8.7 mL, [p < 0.002] and 38.2+/-7.2 mL [p < 0.001], respectively) and dynamic (62.0+/-7.2 [p < 0.02] and 41.3+/-3.5 mL [p < 0.005], respectively) cardiomyoplasty groups compared with controls. In the dynamic group, on and off studies were carried out after cessation of rapid pacing while the heart was still in severe failure, and they demonstrated a systolic squeezing effect in stimulated beats. Only this group recovered fully to baseline after 8 weeks.

CONCLUSIONS

By reducing myocardial stress, both the passive girdling effect and the dynamic systolic squeezing effect have complementary roles in the mechanisms of dynamic cardiomyoplasty.

Massive bleeding from left colonic arteriovenous malformation in a young patient with ventricular septal defect

Arteriovenous malformation of the gut is well known to have been an important bleeding focus in past ages. We report a young Korean male patient, who had been known to have ventricular septal defect, presenting massive lower gastrointestinal bleeding from an arteriovenous malformation involving a long segment of the left colon. Angiographic, gross and histologic findings are presented and the literature is reviewed.

Power generation from four skeletal muscle configurations. Design implications for a muscle powered cardiac assist device

The development of long term cardiac assist devices is currently limited by the lack of an appropriate totally implantable power source. Transformed fatigue resistant skeletal muscle has been proposed as such a power source. The goal of this study was to determine the optimal latissimus dorsi muscle (LDM) configuration capable of obtaining maximum power output. Four separate in situ configurations were prepared: a latex compliance chamber placed between the LDM and chest wall (Sub-Dorsi), a chamber wrapped in a skeletal muscle ventricle (Circular), linear measurements from the thoracolumbar origin (Linear Origin), and linear measurements from the humeral insertion (Linear Insertion). A device was designed to measure the power output from each configuration in watts per kilogram of muscle. Eight LDMs were acutely studied at varying levels of pre-load. Performance characteristics were measured in each configuration. Peak power outputs were as follows: Sub-Dorsi: 8.3 +/- 1.6 W/kg at 50 cc or 11.6 N pre-load; Circular: 16.4 +/- 6.2 W/kg at 50 cc or 16.9 N; Linear Origin: 47.1 +/- 4.4 W/kg at 23.4 N; and Linear Insertion generated 59.9 +/- 12.1 W/kg at 26 N. Analysis of variance comparison revealed a significance of p < 0.0001. A linear oriented LDM is capable of generating maximal power output. Confirmation of these findings in transformed, conformed, fatigue resistant muscle will provide important performance information essential for the optimal design of implantable muscle powered ventricular assist systems.

Hemodynamic response to in situ latissimus dorsi muscle stimulation: implications in dynamic cardiomyoplasty

Dynamic cardiomyoplasty (DCM) involves the electrical stimulation of a pedicled latissimus dorsi muscle flap wrapped around the falling ventricle as a means of cardiac assist. To further elucidate a potential neurohumoral mechanism for improvement of cardiac output after myoplasty, we evaluated the hemodynamic effects of in situ stimulation of the latissimus dorsi muscle (in the absence of cardiomyoplasty). In seven mongrel dogs, a nerve cuff electrode (Medtronic 6901) was placed around the left thoracodorsal nerve (TDN). This was attached to a pulse generator (Medtronic, Itrel 7420), delivering a 4.0 volt, 0.19 second on, 0.81 second off, 33 Hz, 210 microsecond pulse width, cyclic bursts similar to that used in DCM. Stroke volume index (SVI) and other hemodynamic parameters as well as plasma norepinephrine (NE) levels were measured at five stages: baseline, stimulator on at 0, 2, and 5 minutes, and stimulator off at 30 minutes after. The animals were then subjected to 4 weeks of rapid pacing at 240 beats/min (Medtronic 8329) to induce heart failure, and as the rapid pacing was discontinued, measurements were repeated as above. After rapid pacing, cardiac function was significantly depressed, and NE was elevated (133 +/- 69 versus 500 +/- 353 pg/mL, p < 0.05). In the normal hearts, TDN stimulation increased SVI, heart rate, systemic pressure, and NE levels. In heart failure, however, no significant changes in cardiac function and NE levels were noted. In conclusion, our data indicate that in the normal hearts, afferent impulses from TDN stimulation alone may augment cardiac function by means of a neurohumoral effect that is not seen in severe heart failure. The implications of these findings in DCM are discussed.

Bax accelerates staurosporine-induced but suppresses nigericin-induced neuronal cell death

Bax, a member of the Bcl-2 multigene family, is known to promote apoptosis. To investigate the role of Bax in an experimentally induced cell death of the murine dopaminergic neuronal cell line (MN9D), we established MN9D cells stably over-expressing murine Bax (MN9D/ Bax) or vector alone (MN9D/Neo). In MN9D/Neo cells treated with either 1 microM staurosporine or 0.1 microM nigericin, a ladder pattern of DNA fragmentation was induced. As expected, over-expression of Bax in MN9D cells accelerated staurosporine-induced cell death as measured by the MTT reduction assay (62.3% survival in MN9D/Neo vs 27.0% survival in MN9D/Bax). Surprizingly, both nigericin-induced cell death and its accompanying DNA fragmentation were largely attenuated in MN9D/Bax cells (22.0% survival in MN9D/Neo vs 86.7% survival in MN9D/Bax). Similar patterns were observed in two other MN9D/Bax cell lines. Cleavage of poly(ADP-ribose)polymerase caused by nigericin was greatly attenuated in MN9D/Bax cells suggesting that, like Bcl-2, Bax suppresses nigericin-induced cell death by inhibiting the activation of cysteine proteases. Thus, our data imply that Bax acts as a negative or positive regulator of cell death depending on the type of death stimulus applied to the cell.

Psychiatric illness and syncope

Studies have reported a high prevalence of psychiatric illness in patients with syncope, particularly among those with syncope of unknown etiology. Although mortality rates for patients with syncope and psychiatric disorders tend to be lower than for patients with cardiac cause for syncope, treatment of these psychiatric illnesses appears to result in lower rates of recurrence of the symptoms. The authors recommend an assessment for psychiatric illness in those patients in whom the initial evaluation does not suggest an organic cause for syncope. Further studies are needed to elucidate the pathophysiologic mechanisms for syncope and the effects of treatment of psychiatric illness on recurrence of syncope.

Genetic variations of the apo E-CI-CII cluster gene in Koreans

OBJECTIVES

To investigate the allele frequencies of the apolipoprotein (apo) E-CI-CII cluster gene in Koreans, and its relation to plasma lipid and lipoprotein levels.

METHODS

The study subjects consisted of healthy Korean individuals (apo E, 145; apo CI and CII, 81) who were randomly selected via health screening. For polymorphism analysis, DNA was amplified by polymerase chain reaction (PCR). The one-way analysis of variance (ANOVA) test was performed to compare the mean of lipid levels among different genotypes.

RESULTS

The apo E polymorphism in the Korean population appeared as the E4/2, E3/2, E3/3, E4/3, and E4/4 genotypes. The epsilon 3 allele was the most frequent, as in other populations. The apo E polymorphism showed the lack of association with plasma lipid levels in this population. On the other hand, we demonstrated AvaII polymorphism of the apo CII gene by PCR technique. Cholesterol and triglyceride levels were varied significantly among the AvaII genotypes (p < 0.05).

CONCLUSION

No effect of the apo E allele on lipid levels was seen in the Korean population. This result suggests that it might be one of the factors in explaining the low prevalence rate of atherosclerosis in the Korean population. Also, the AvaII polymorphism analysis by PCR is a simple and less time-consuming method.

Establishment and characterization of human gastric carcinoma cell lines

We report 8 newly established gastric-carcinoma cell lines (SNU-216, 484, 520, 601, 620, 638, 668, 719) from Korean patients. Morphologic study was carried out using light and electron microscopes. CEA, alpha FP, and CA 19-9 and TPA in supernatant and in cell lysate were measured by radioimmunoassay. p53 and c-Ki-ras gene mutations were screened and confirmed by sequencing. The cell lines, derived from tumors with moderate differentiation, grew as a diffuse monolayer, and those from tumors with poor differentiation and minimal desmoplasia grew exclusively as non-adherent. Out of the 8 gastric-cancer cell lines, 5 had detectable levels of CEA both in supernatant and in cell lysate; there was no expression or secretion of alpha FP in these cells; 4 cell lines showed high levels of CA 19-9 in cell pellets. All cell lines except SNU-484 had high concentrations of TPA both in cell lysate and in supernatants. p53 mutation was found in 6 cell lines (75%): 2 (SNU-216 and SNU-668) had mutations in exon 6, and other 3 in exon 8. The c-Ki-ras mutation was found in 2 cell lines (25%), SNU-601 and SNU-668. The former showed GGT-to-GAT transition mutation at codon 12, while the latter showed CAA-to-AAA transversion mutation at codon 61. DNA profiles using restriction endonuclease HinfI and polymorphic DNA probes ChdTC-15 and ChdTC-114 showed different unique patterns; which suggests that these cell lines are unique and not cross-contaminated. We believe that the newly characterized gastric-cancer cell lines presented in this paper will provide a useful in vitro model for studies related to human gastric cancer.

Mechanisms of dynamic cardiomyoplasty: current concepts

Dynamic cardiomyoplasty is an operation that is undergoing worldwide clinical evaluation. It had been developed to utilize the patient's own skeletal muscle to assist the failing heart. Although the clinical and quality of life benefits of cardiomyoplasty have been reported in most patients, the results of quantitative hemodynamic analyses have been less consistent. This has prompted the reevaluation of the mechanisms of dynamic cardiomyoplasty other than simple cardiac compression by the wrapped muscle. There is good evidence to suggest that the following, either together or in part, comprise some of the mechanisms of dynamic cardiomyoplasty: (1) direct systolic assist; (2) myocardial (wall stress) sparing effect; (3) remodeling/girdling effect; and (4) angiogenesis. Current concepts and potential additional mechanisms are discussed and integrated, based on a review of the literature and our own recent studies.

Cementless total hip arthroplasty in patients with osteonecrosis of the femoral head

The authors studied 61 patients (78 hips) who had avascular necrosis of the femoral head, seen in followup for an average of 7.2 years (range, 6-9 years) after they had primary cementless porous-coated total hip arthroplasty. This study was undertaken to determine whether cementless porous-coated prostheses have any merit over reported cemented total hip arthroplasty using contemporary techniques. The average age of the patients at the time of surgery was 48 years old (range, 20-73 years). The average preoperative hip score was 45.6 points (range, 28-75 points), which improved to 90.3 points (range, 34-100 points) at the 7.2-year followup examination. Sixteen of 78 arthroplasties failed in the period of followup, for an overall failure rate of 20.5%. Of the failed hips, 11 had femoral component loosening, 4 had femoral and acetabular component loosening, and 1 had excessive wear in the polyethylene liner. Four femoral components and 5 acetabular components were revised. Twenty-one of the 78 hips (27%) had an average of 5.6 mm (range, 3-9 mm) of wear in the polyethylene liner. Sixteen (20.5%) of 78 hips had acetabular and femoral periprosthetic osteolysis, and 22 (28.2%) hips had femoral periprosthetic osteolysis only. The cementless total hip arthroplasty in this series had a higher incidence of aseptic loosening of the femoral component, polyethylene liner wear, and periprosthetic osteolysis than that reported for cemented total hip arthroplasty using contemporary techniques.

Evaluation of the anatomic patellar prosthesis in uncemented porous-coated total knee arthroplasty: seven-year results

We studied 41 patients (56 knees; mean patient age, 55.3 years) who were followed up for a minimum of 7 years (range, 84 to 90 months) after primary resurfacing arthroplasty of the patella with an anatomic patellar prosthesis during uncemented porous-coated anatomic total knee arthroplasty. The operative diagnosis was osteoarthritis in 33 knees; rheumatoid arthritis in 16; tuberculous arthritis in 4; posttraumatic arthritis in 2; and ankylosis in 1. The average preoperative Hospital for Special Surgery knee score was 33 points (range, 10 to 69 points), which improved to 81 points (range, 54 to 100 points) at the final follow-up examination. There was a high rate of component loosening (23 knees or 41%). A total of 27 of 33 solidly fixed patellar prostheses (82%) had osteolysis in the patella. Forty-two knees (75%) had wear of the tibial polyethylene liners; a mean of 2.5 mm in the medial compartment and 1.7 mm in the lateral compartment. Our experience does not support the continued use of this prosthesis.

Osteolysis around cementless porous-coated anatomic knee prostheses

We report the incidence of osteolysis in the femur, tibia, and patella of 44 consecutive patients (60 knees) who were followed for more than seven years after cementless knee arthroplasty with a Porous-Coated Anatomic prosthesis. The average age of the patients was 56.5 years (17 to 73); the operative diagnosis was osteoarthritis (33 knees), rheumatoid arthritis (17), tuberculous arthritis (7) and post-traumatic arthritis (3). All patellae were resurfaced. No femoral or tibial component was loose at the final follow-up examination. Thirty patellar components were loose of which six had been revised. Radiographs revealed osteolysis in 90% of the tibial plateaux and in 80% of the 30 intact patellar prostheses. No osteolysis was seen around any femoral component. In 50 knees (83%) the average wear of the polyethylene liner was 2.5 mm in the medial compartment and 1.7 mm in the lateral compartment. Four of 60 knees (6.7%) were revised for complete wear of the polyethylene liner of the tibial component. Fixation of the tibial and patellar components without cement fails to seal the interface between bone and prosthesis and allows the migration of polyethylene particulate debris which causes osteolysis.

Osteolysis around cementless porous-coated anatomic knee prostheses

We report the incidence of osteolysis in the femur, tibia, and patella of 44 consecutive patients (60 knees) who were followed for more than seven years after cementless knee arthroplasty with a Porous-Coated Anatomic prosthesis. The average age of the patients was 56.5 years (17 to 73); the operative diagnosis was osteoarthritis (33 knees), rheumatoid arthritis (17), tuberculous arthritis (7) and post-traumatic arthritis (3). All patellae were resurfaced. No femoral or tibial component was loose at the final follow-up examination. Thirty patellar components were loose of which six had been revised. Radiographs revealed osteolysis in 90% of the tibial plateaux and in 80% of the 30 intact patellar prostheses. No osteolysis was seen around any femoral component. In 50 knees (83%) the average wear of the polyethylene liner was 2.5 mm in the medial compartment and 1.7 mm in the lateral compartment. Four of 60 knees (6.7%) were revised for complete wear of the polyethylene liner of the tibial component. Fixation of the tibial and patellar components without cement fails to seal the interface between bone and prosthesis and allows the migration of polyethylene particulate debris which causes osteolysis.