Suppressed production of nitric oxide as a cause of irregular constriction of gastric venules induced by thermal injury in rats

Microcirculatory disturbance is a crucial step in development of gastric mucosal lesions. In this study we investigated the influence of nitric oxide (NO) on the irregular constriction of gastric venules observed in rats subjected to thermal injury. Male Wistar rats were anesthetized and a 30% full skin thickness dorsal burn was inflicted. Microvascular images in the submucosal layer and basal region of the gastric mucosa were obtained through an intravital microscope. Distribution of constitutive-type nitric oxide synthase (cNOS) was observed by the immunofluorescence method. Venule walls were basically smooth in the control group (no injury), whereas irregular constrictions tended to be observed in the 5-h group (5 h after thermal injury). Venule diameter was significantly smaller in the 5-h group. In the control group, cNOS-associated fluorescence was found on the venule endothelium, whereas it was almost negligible after thermal injury. A NO donor, 3-morpholinosydnonimine hydrochloride, simultaneously diminished the thermal injury-associated venule constriction and irregularity of venule walls. Therefore, the present study suggests that venule constriction, which is observed 5 h after thermal injury, is related to decreased NO production by endothelial cNOS and is a cause of irregularity of the venule walls.

Matrix metalloproteinase gene expression in chronic gastric ulcer: a potential role of eosinophils in perforation

Gene expression of matrix degrading enzymes was investigated in surgical specimens of perforated gastric ulcers. In these ulcers, the inflammatory cells infiltrating into the granulation tissue were granulocytes, particularly eosinophils. The extracellular matrix of the stomach wall consists mainly of collagen types I and III, which are selectively degraded by matrix metalloproteinase-1 (MMP-1). MMP-1 mRNA was detected in the cytoplasm of infiltrating cells, suggesting that eosinophils play an important role in ulcer recurrence and in perforation of the stomach wall. The degree of eosinophil infiltration into an ulcer base may be a useful marker for the risk of perforation. Patients showing this marker may benefit from a prophylactic therapy for preventing severe complications. The control of MMP gene expression represents a potential strategy for the treatment of recurrent gastric ulcer.

A protease inhibitor attenuates gastric erosions and microcirculatory disturbance in the early period after thermal injury in rats

The effects of camostat mesilate, a synthetic serine protease inhibitor on gastric microcirculation and active oxygen species generated by leucocytes from the gastric and jugular veins in the early period after thermal injury were assessed. Male Wistar rats were anaesthetized and a 30% full skin-thickness dorsal burn was inflicted. Camostat mesilate (100 mg/kg) was dissolved in distilled water and administered orally to rats 40 min before thermal injury (the camostat group). The control animals (the vehicle group) were administered distilled water orally. Rolling leucocytes as well as Monastral blue B deposits in venules were observed using in vivo microscopy. Active oxygen species were measured by chemiluminescence. Camostat mesilate decreased the total length of gastric erosion, venular deposits of Monastral blue B, and rolling of leucocytes in venules, and relatively increased luminol-dependent chemiluminescence activity generated by zymosan-stimulated leucocytes 15 min after thermal injury. These results suggest that serine proteases are involved in the formation of gastric erosions and gastric microcirculatory disturbance in the early period after thermal injury.

[Laparoscopic wedge resection of the stomach for early gastric cancer using a lesion-lifting-method: curative and minimally invasive treatment]

Thirty-eight patients with early gastric cancer have been successfully treated by laparoscopic wedge resection of the stomach in our institute since March 1992. Our indication of the surgery is as follows: 1) preoperatively diagnosed mucosal cancer, 2) < 25 mm, if the lesion is elevated type, and 3) < 15 mm and no ulcer scar, if the lesion is depressed type. After laparoscopic exposure of the gastric wall around a cancerous lesion, a sheathed needle was inserted into the stomach through the abdominal wall at the vicinity of the lesion under gastroscopy guidance. A small metal rod was introduced into the stomach near the lesion through the outer sheath. While the lesion was lifted up precisely with the support of the metal rod, wedge resection of the stomach was performed using an endoscopic stapler (lesion-lifting method). Perigastric lymph nodes could be also resected when necessary. There was no intraoperative and postoperative complication, and no mortality. The patients were discharged within 5 days after surgery uneventfully. The resected specimens were 50 to 110 mm in diameter, and there was a sufficient surgical margin (16 +/- 5mm). All patients have survived during the 2 to 60 months follow-up period. There has been one recurrence and one separate occurence of early gastric cancer in the series, which were curatively treated by gastrectomy. Advantages of the surgery are as follows: 1) it is minimally invasive, 2) most of the stomach is preserved, 3) a sufficient surgical margin can be obtained, and 4) a detailed histologic examination is feasible. If the indication is selected properly, this laparoscopic surgery can be a curative and minimally invasive treatment for early gastric cancer.

[Limited operation for lung cancer: wedge resection using stapling device]

We employed wedge resection using stapling device for peripheral, clinical stage I lung carcinoma in selected poor-risk patients. Out of 10 patients, four developed local recurrence and one had the second primary in the same lobe resected. Compared with patients having lobectomy with 91% of a recurrence free rate in three years, those who underwent wedge resection had the lower rate of 53%. We conclude that wedge resection using stapling device cannot be an acceptable procedure even for poor-risk patients.

Availability of nasal mask BiPAP systems for the treatment of respiratory failure after cardiovascular surgery

BACKGROUND

The availability of nasal mask bi-level positive airway pressure (BiPAP) support in managing respiratory failure following cardiovascular surgery was studied.

MATERIALS AND METHODS

BiPAP support was used for eight patients requiring postoperative prolonged respiratory support of 72 hours or longer. Their mean age was 65 years of age and the mean periods of postoperative endotracheal intubation was 12+/-5 days. BiPAP support was removed within 48 hours in six out of eight patients. Reintubation of an endotracheal tube was not necessary in all eight patients after the BiPAP treatment.

RESULTS

The respiratory rates during the BiPAP management remained unchanged. The values of the respiratory index significantly (p<0.01) improved after BiPAP management (1.5+/-0.2 --> 0.9+/-0.2). A-aDO2 and Qs/Qt decreased (p<0.1) after the BiPAP management. There were no significant differences in central venous pressure and circulatory states during BiPAP support.

CONCLUSIONS

In conclusions, BiPAP support is a noninvasive management technique for postoperative respiratory failure and may also prevent prolonged endotracheal intubation.

Arterial embolization as preoperative treatment for pulmonary aspergillosis with hemoptysis

Pulmonary aspergillosis associated with old tuberculosis is generally resistant to treatment. Thus, if patients are treated only with conservative therapy, their condition continues to deteriorate due to repetitive hemoptysis, and may even become critical. Surgical treatment is required for these patients; however, it is extremely difficult to resect the lesion due to severe adhesions to the chest wall and vascular proliferation surrounding the lesion. We performed preoperative arterial embolization, achieving good results in three patients with hemoptysis caused by pulmonary aspergillosis. The feeding arteries were embolized using microcoils and/or gelatin sponges, and a lobectomy was safely carried out in all patients. We concluded that preoperative arterial embolization is a safe and effective technique to prevent massive hemorrhage occurring at the time of surgery.

Expression of matrix metalloproteinase-1 mRNA related to eosinophilia and interleukin-5 gene expression in head and neck tumour tissue

In situ hybridization (ISH) of the expression of matrix metalloproteinase-1 (MMP-1) in areas of local invasion of head and neck tumours was performed. Expression of MMP-1 mRNA was found in stromal inflammatory cells adjacent to the tumour nests, apparently in eosinophils. MMP-1 mRNA expression was seen only in cases with moderate or greater stromal eosinophilia. MMP-1 mRNA was detected in benign papilloma and verrucous carcinoma. In squamous cell carcinomas, expression of the gene was detected only in well-differentiated cases. Expression of MMP-1 mRNA was not related to the grade of malignancy, and appeared in stromal eosinophils, suggesting to us that it is involved in a remodelling process in the reaction of the host to tumour invasion. ISH examination of the expression of interleukin-5 (IL-5), the activating factor for eosinophils, was also performed. In the tumour, its expression was consistent with the location of eosinophils, as with MMP-1 mRNA, suggesting an autocrine mechanism.

The role of stromal cells in the expression of interstitial collagenase (matrix metalloproteinase-1) in the invasion of gastric cancer

BACKGROUND AND OBJECTIVES

In one of the steps of tumor invasion and metastasis, tumor cells must invade surrounding tissues and degrade the components of the basement membranes. Interstitial collagenase (matrix metalloproteinase-1: MMP-1) has been also investigated in relation to cancer invasion and metastasis.

METHODS

We investigated the formation and mechanism of MMP-1 expression using gastric cancer cell lines and gastric fibroblasts derived from normal gastric mucosa by ELISA and immunohistochemistry.

RESULTS

Production of MMP-1 protein in gastric fibroblasts was stimulated significantly by adding the conditioned medium of MKN-74. Localization of MMP-1 protein in the xenografted gastric cancer cell lines was heterogeneous according to different cell lines.

CONCLUSIONS

These results suggested that the production of MMP-1 protein in tumor invasion was regulated by interaction between stromal cells, particularly fibroblasts, and tumor cells.

Left-sided approach to renal cell carcinoma tumor thrombus extending into suprahepatic inferior vena cava by resection of the left caudate lobe

A new operative approach to resecting tumor thrombus originating from a right renal cell carcinoma extending into the suprahepatic inferior vena cava (IVC) is reported. Complete local control of the IVC must be obtained above and below the tumor thrombus to remove it under direct vision. The caudate lobe of the liver was resected to expose the retrohepatic IVC and open the lesser omentum. The subhepatic IVC was encircled just below the confluence of the hepatic veins. Caval tumor thrombus was removed en bloc, including the right kidney, by use of the total hepatic vascular exclusion technique (THVE) and IVC exclusion. The retrohepatic IVC was clamped just below the confluence of the hepatic veins once the thrombus was removed, and the suprahepatic IVC clamp was then released and the THVE was terminated. The sequential clamping from the suprahepatic IVC to the retrohepatic IVC below the confluence of the hepatic veins shortened the THVE time.

[Jejunal pouch interposition after total gastrectomy]

The results and procedures of interposed jejunal pouch after total gastrectomy for gastric cancer are reported. Basic requirements of reconstruction after total gastrectomy are 1) formation of a food reservoir, 2) maintenance of duodenal continuity, 3) avoidance of reflux esophagitis, 4) gradual emptying of reservoir into the small intestine. Since 1950's, several procedures of gastric substitutes have been reported. But they were not widely performed. Because scientific evaluation of the value of gastric substitutes was difficult and the operative procedures were time consuming and complicated. With an increasing ratio of early gastric cancer in 1990's, the importance of post-operative QOL, such as food intake and body weight maintenance, in patients after total gastrectomy has been recognized. Our procedure is a double lumen jejunal pouch distal to a interposed jejunum. The length of interposed jejunum is 20 cm and that of pouch is 10 cm. Using surgical staplers, this procedure is safe and simple. Jejunal pouch interposition leads to a satisfactory symptomatic and nutritional result in gastrectomized patients.

[Clinical criteria of chemosensitivity test]

Chemosensitivity test is useful in evaluating the appropriate cancer chemotherapy for solid tumors which are less sensitive to conventionally available antitumor agents. Most of assays used in clinics are in vitro assay, in which the cutoff concentration and contact time should be determined to mimic the clinical response of the chemosensitivity test. Since the antitumor effect of most of antitumor agents depends on their concentration x contact time, and the contact time will be determined according to the assay, the cutoff concentration will be calculated from the cumulative efficacy curve or 50% inhibitory concentration and in vivo response of human tumor xenografts in nude mouse. The clinical result obtained from chemosensitivity test was discussed.

Surgical management of gastric leiomyosarcoma: evaluation of the propriety of laparoscopic wedge resection

Laparoscopic surgery has been applied to malignant gastric tumors. To evaluate the propriety of laparoscopic wedge resection for gastric leiomyosarcoma it is necessary to question whether lymph node dissection is necessary for the surgical management of gastric leiomyosarcoma. A retrospective study on open surgery cases of gastric leiomyosarcoma was performed to address this issue. The clinical records of 28 patients with gastric leiomyosarcoma who had had surgery were examined. The patients who underwent open surgery were divided into a systematic lymph node dissection (SLND) group (n = 9) and a nondissection (non-D) group (n = 19). No patient had lymph node metastasis at the time of operation or recurrence, and statistical analysis showed no difference between the SLND and non-D groups in terms of survival rates. These data suggest that SLND might not be necessary for the surgical management of gastric leiomyosarcoma and that laparoscopic wedge resection of the stomach can be considered a first-line treatment for gastric leiomyosarcoma.

Expression of interstitial collagenase (matrix metalloproteinase-1) in gastric cancers

The expression of matrix metalloproteinase-1 (MMP-1) gene and the presence of MMP-1 protein in gastric cancer were examined by in situ hybridization and immunohistochemistry. Expression of the interstitial collagenase (MMP-1) gene was detected within the stroma of the neoplastic glands, and infiltration of eosinophils was observed to be associated with regions of MMP-1 gene expression. The degree of eosinophilic infiltration correlated with the level of MMP-1 mRNA expression. Immunostaining showed localization of MMP-1 protein in the stromal cells, and additionally in the neoplastic glands. These findings indicate that the stromal cells may play an important role in the expression of MMP-1, and suggest a pathophysiological role for MMP-1 in the invasion and metastasis of gastric cancer.

Difference in gene expression for matrix metalloproteinase-1 between early and advanced hepatocellular carcinomas

The histological observation that well-differentiated cancer cells in early hepatocellular carcinoma (HCC) invade portal tracts and/or fibrous bands and that these fibrous tissues then disappear suggests the participation of matrix metalloproteinase-1 (MMP-1) in the degradation of fibrous tissue. To confirm this hypothesis, the authors investigated the localization of both the MMP-1 protein and its messenger RNA (mRNA) in early HCC immunohistochemically and by in situ hybridization using complementary DNA (cDNA) and synthetic antisense probe of MMP-1; they then compared the results with those in advanced HCC. MMP-1 gene transcripts and protein were observed in well-differentiated cancer cells of early HCC but not in moderately or poorly differentiated cancer cells. Thus, cancer cells producing MMP-1 in early HCC may destroy the portal tract tissue adjacent to the cancer lesion and/or the fibrous band of cirrhosis. These results seem to have demonstrated a difference in the mechanism of cancer growth and invasion between early and advanced HCCs.

[Laparoscopic surgery for early gastric cancer--its advantage and pitfall]

We have successfully treated 50 patients with early gastric cancer by using two different laparoscopic procedures since March 1992. which are laparoscopic wedge resection of the stomach using a lesion-lifting method (n = 33) and laparoscopic intragastric mucosal resection (n = 17). The indication is as follows; (A) mucosal cancer, (B) < 25 mm, if the lesion is protruded type, (C) < 15 mm and Ul(-), if the lesion is depressive type. The advantages of these methods are; 1) minimally invasiveness. 2) sufficient surgical margin, 3) feasibility of detailed histology, 4) feasibility of perigastric lymph node dissection. In contrast, there are several problems to be solved, which are; 1) preoperative diagnostic accuracy of the depth of cancer invasion, 2) possibility of reoperation because of sm invasion or lymphatic or venous invasion in final histology, 3) possibility of postoperative stenosis after laparoscopic intragastric mucosal resection for the lesion near the cardia, 4) incidence of metachronous multiple gastric cancer.

Malfunctioning Starr-Edwards mitral valve 21 years after installation

Two cases of malfunctioning Starr-Edwards cloth-covered mitral valve prostheses requiring reoperation are presented. Both cases underwent successful surgical repair 21 years after the valve replacement. The causes were a disturbance of the poppet during the opening movement due to excessive tissue ingrowth and a paravalvular leak associated with a tear of the valve seat. Replacement of the Starr-Edwards valve prosthesis more than 20 years after the initial installation has not been reported.

Interferons alpha-2a and beta increase the antitumor activity, detected by MTT assay, of 5-fluorouracil against experimental and clinical human gastrointestinal carcinomas

In order to investigate the combined antitumor activity of 5-fluorouracil (5-FU), and recombinant human interferon alpha 2a (IFN alpha) or human fibroblastoid interferon beta (IFN beta), the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay was carried out using a cultured human colon cancer cell line (C-1) and fresh surgical specimens of gastric and colon carcinomas. IFNs did not show positive antitumor activity against C-1 cells, whereas 5-FU showed time- and concentration-dependent antitumor activity against C-1 cells. Furthermore, the antitumor activity of 5-FU on C-1 cells was augmented by IFN alpha or beta. When 5-FU (50 micrograms/ml) with IFN alpha (50 IU/ml). or IFN beta (50 IU/ml) was applied for the MTT assay with 48 hours incubation of fresh surgical specimens of gastric and colon carcinomas, the inhibition rates increased by 10% in 9 of 21 gastric specimens and in 18 of 36 colon carcinomas for IFN alpha (47.4% or 27/57), and in 8 of 15 gastric specimens and in 15 of 28 colon carcinomas for IFN beta (53.5% or 23/43). These results suggest that the chemosensitivity to 5-FU of human gastric and colon carcinomas is increased in the presence of IFNs, without involvement of the host-mediated immune system, and that this combined effect can be predicted by the MTT assay in vitro.

Benign tumors of the lung: a 20-year surgical experience

In the following report, we describe our investigation of the diagnosis and operative methods for benign tumors of the lung, in which the surgical treatment was selected due to suspicious malignancy. This study included 22 patients with benign tumors. The patients' mean age was 55 years old. The histological diagnosis was made postoperatively prior to 1985 and intraoperatively after 1986. Hamartoma was the most common of the benign tumors. In benign tumors, the preoperative diagnosis was almost the same as the postoperative one. Of the patients with benign tumors, 78% underwent lobectomy or segmentectomy prior to 1985, and none have undergone any invasive procedures since 1986. Malignant tumors are sometimes difficult to distinguish from benign tumors preoperatively. Therefore, intraoperative histological examinations are necessary in cases in which malignancy is suspected. In such cases, a smaller invasive procedure should be selected due to the possibility of the tumor being benign.