Ultrastructural investigations for reducing endothelial cell damage of vein grafts during CABG-operation and practical consequences.

BACKGROUND: In the present study the influence of different storage solutions on endothelial integrity or damage was investigated with direct methods particularly with transmission electron microscopy (TEM), scanning electron microscopy (SEM) and immunohistochemistry. METHODS: Saphenous vein segments of 10 cm in length were taken surgically from 6 male CABG-patients (aged 60-70) under standardized conditions. Each vein segment was cut into rings, which were incubated at room temperature for 45 minutes in different storage solutions, particularly in 0.9% sodium chloride solution and in buffered solution (M 199) with 5% human serum albumin respectively. Then, the vein segments were fixed in 3.5% glutaraldehyde and prepared for scanning and transmission electron microscopy to evaluate the endothelial damage. In addition, immunohistochemical staining (CD34, PECAM and Factor VIII) was performed. RESULTS: When using 0.9% sodium chloride solution, the SEM-examination revealed that 55% of the cell population was destroyed. In comparison to these findings only 26% of the endothelial cell population was damaged when the venous segment was stored in buffered solution with 5% albumin (p<0.01). In immunohistochemistry (CD34, PECAM, Factor VIII) these findings were supported. CONCLUSIONS: This study demonstrates the importance of storage solutions in regard to endothelial integrity. For best preservation of endothelium it is necessary to modify conventional storage methods. So, storage in buffered solution with albumin has shown much better endothelial cell preservation compared with physiological saline which might reduce the obliteration rate of CABG in future.

The effect of oral protease administration in the rat remnant kidney model.

It has been demonstrated that intraperitoneal administration of proteolytic enzymes ameliorates the progression of renal diseases in various animal models. In the present study, we employed the rat remnant kidney model to study the effectiveness of oral administration of proteases. Twenty male Wistar rats underwent sham operation (CTRL), while 25 were subjected to 5/6 nephrectomy (5/6 NX). Rats were randomised into placebo (PL) (2 ml tap water/day by gavage), or Phlogenzym (E; fixed mixture of trypsin 2.42 mg, bromelain 4.54 mg, and rutozid 5.04 mg added as antioxidant, in 2 ml tap water daily by gavage) treated group. Duration of the study was 45 days. Rats were pair-fed. Enzyme treatment exerted salutary effects on various functional and morphological parameters. Proteinuria was higher in both 5/6 NX group rats throughout the study. Administration of proteases ameliorated its rise effectively (data at sacrifice: CTRL-PL 6.27 +/- 1.25, CTRL-E 9.27 +/- 0.99, 5/6 NX-PL 74.04 +/- 21.33, 5/6 NX-E 39.09 +/- 7.93 mg/24 h; P < 0.01). Increased urinary excretion of the fibrogenic cytokine transforming growth factor (TGF-beta 1) was improved, too (CTRL-PL 0.349 +/- 0.051, CTRL-E 0.693 +/- 0.230, 5/6 NX-PL 3.044 +/- 0.540, 5/6 NX-E 1.390 +/- 0.238 ng/mumol creatinine; P < 0.05). At sacrifice, tubulointerstitial fibrosis was less pronounced in E-treated rats. Correspondingly, the volume fraction of tubulointerstitial tissue in the renal cortex was improved in 5/6 NX-E rats (CTRL-PL 9.9 +/- 0.2, CTRL-E 10.0 +/- 0.2, 5/6 NX-PL 17.9 +/- 1.8, 5/6 NX-E 13.8 +/- 0.9%; P < 0.05). The protein/DNA ratio in isolated glomeruli and tubules, as an estimate of glomerular matrix accumulation and hypertrophy of tubules, was enhanced in 5/6 NX groups and a tendency towards lower values was observed after E treatment. Renal function as evaluated by serum creatinine and urea levels was not influenced by the enzyme therapy. No between-group differences in blood pressure were observed. In summary, oral administration of proteolytic enzymes improved proteinuria and urinary TGF-beta 1 excretion, as well as the severity of tubulointerstitial fibrosis without signs of toxicity.

Effect of chronic therapy with proteolytic enzymes on hypertension-induced renal injury in the rat model of Goldblatt hypertension.

This study investigated the possible beneficial effect of intraperitoneal proteolytic enzyme administration on the development of hypertension-induced renal injury in the rat model of 2-kidney 1-clip (2K1C) Goldblatt hypertension. Male Wistar rats (120-150 g) underwent either sham surgery (control, n = 5) or clipping of the left renal artery. From day one 2K1C rats were randomized into 2 groups, placebo treatment (n = 7), and proteolytic enzyme treatment (n = 9). To the verum group a fixed mixture of trypsin (2.42 mg), bromelain (4.54 mg), and rutin (5.04 mg) dissolved in 2 ml of sterile 0.9% NaCl was administered intraperitoneally daily, while the placebo group received only vehicle. Rats were pair-fed. The duration of the study was 7 weeks. All 2K1C rats developed hypertension and the mean values of systolic blood pressure (SBP) did not differ significantly between the groups at any time recorded (SBP at sacrifice: controls 122.0 +/- 8.5 mm Hg; placebo 191.4 +/- 7. 6 mm Hg; enzyme 180.5 +/- 6.5 mm Hg). Enzyme treatment prevented the rise in proteinuria (controls 12.4 +/- 2.6 mg/24 h; placebo 19.7 +/- 3.9 mg/24 h; enzyme 12.2 +/- 1.3 mg/24 h; p < 0.05) and ameliorated the increase in serum urea concentrations. Histomorphologically, signs of malignant nephrosclerosis were not found in control rats, while they were present in 4/7 (57%) of placebo-treated rats, but only in 1/9 (11%) of the enzyme-treated group. The volume fraction of renocortical interstitium was increased in both 2K1C groups in comparison with controls; however, enzyme treatment decreased the accumulation of interstitial tissue significantly (-22%) compared to placebo treatment. Cellular infiltration with mononuclear cells was also lower in the protease-treated group. To summarize, in the rat model of 2K1C hypertension, systemic treatment with proteases ameliorates the severity of nephrosclerosis and tubulointerstitial fibrosis in the non-clipped kidney, as well as proteinuria, without affecting high blood pressure.

[Lipoma of the adrenal gland. Case report and review of the literature]. / Lipom der Nebenniere. Fallbericht und Literaturübersicht.

Adrenal lipomas are extremely rarely occurring benign tumors being hormonally inactive. The patient described in this report underwent surgical excision of an adrenal lipoma because of the associated hypertension. The blood pressure decreased postoperatively to normal levels. This case report and the review of the literature consider diagnosis and therapy of the adrenal lipomas.

Tumor-specific apoptosis induced by the human monoclonal antibody SC-1: a new therapeutical approach for stomach cancer.

Stomach cancer is one of the most frequently occurring cancers worldwide, with a very poor prognosis, even after complete gastrectomy. We describe here an alternative therapeutical approach using a human monoclonal antibody (SC-1), which was isolated from a patient with diffuse-type gastric adenocarcinoma. We demonstrate that the antibody significantly reduces stomach cancer growth in vivo, by inducing tumor-specific apoptosis and that the antibody, even delivered in high doses, shows no toxic crossreactivity to other organs or tissues. The data presented here show that tumor-specific apoptosis can be induced and they give rise to the hope that human monoclonal antibodies with biological activity might present a completely new type of adjuvant cancer therapy.

Is the expression of multidrug resistance gene product a prognostic indicator for the clinical outcome of patients with renal cancer?

OBJECTIVE: To determine the significance of the expression of the multidrug resistance gene product (MDR-1) for the aggressiveness of renal cell carcinoma (RCC). PATIENTS AND METHODS: The study comprised 31 patients with clinically locally confined RCC treated with radical nephrectomy (mean age 64.1 years, range 41-78; mean follow-up 5.4 years, range 4.3-7.3). Their survival time and disease-free period were evaluated retrospectively. The expression of the MDR-1 gene product was determined immunohistochemically using the JSB-1 antibody in formalin-fixed paraffin-embedded tumour samples from these patients. The significance of this variable and tumour stage and malignancy grade was assessed for predicting the survival and disease-free period using Kaplan-Meier plots (log-rank test or Tarone's test) and the Cox multiple hazard regression analysis. RESULTS: In a univariate analysis, tumour stage (P < 0.002), malignancy grade (P < 0.007) and MDR-1 (P < 0.03) were significant prognostic variables for both survival and disease-free period. Lower MDR-1 expression was correlated with poorer prognosis. On multivariate analysis, MDR-1 and tumour stage were significant factors for predicting the disease-free period, whereas tumour stage and malignancy grade were the most relevant factors for survival time. Calculating prognostic indices based on the results of the Cox analysis, MDR-1 could replace malignancy grade, resulting in a better prediction of survival and disease-free period (P < 0.001 vs 0.0031, P < 0.001 vs 0.021, respectively). CONCLUSION: MDR-1, an established predictor for chemo-resistance, may also be a potent prognostic factor for outcome in patients with locally confined RCC. Moreover, MDR-1 expression seems to correlate with the differentiation of the RCC and thus its value as an objective measure of the degree of differentiation should be further explored.

[Coincidence of pulmonary cryptococcoma in an immunocompetent patients with a chondrohamartoma and chronic tuberculoma--differential diagnostic considerations concerining pulmonary coin lesions]. / Koinzidenz eines pulmonalen Kryptokokkoms bei einem immunokompetenten Patienten mit einem Chondrohamartom und einem alten Tuberkulom--Differentialdiagnostische Erwägungen über Lungenrundherde.

Of primary importance in the differential diagnosis of multiple circular foci in the lungs are the lung metastases. This study involves a patient with three circular foci, each of which could have been metastases. They proved, however, to be a rare coincidence of three benign lung affections, namely, an old tuberculoma, a chondrohamartoma, and a seldom encountered pulmonary cryptococcoma. Computerized tomography utilizing the spiral technique was valuable diagnostically, as it led to the discovery of the smallest of the three circular foci in the basodorsal left lower lobe. The form of the cryptococcosis among immunocompetent patients--only rarely localized in our experience--must be included in the differential diagnostical considerations of a circular focus in the lungs. In the event there are multiple circular foci with an unknown primary tumor, surgical intervention with a pathohistological clarification regarding a possible malignancy is absolutely necessary.

Effects of early and late antihypertensive treatment on extracellular matrix proteins and mononuclear cells in uninephrectomized SHR.

The efficacy of an early and late treatment with the angiotensin converting enzyme inhibitor lisinopril or the angiotensin II receptor blocker ICI D8731 was investigated in uninephrectomized spontaneously hypertensive rats (SHR). Rats that underwent uninephrectomy (UNX) at six weeks of age were randomly assigned to receive no treatment, lisinopril shortly after UNX, lisinopril starting 16 weeks after UNX, ICI D8731 shortly after UNX, and ICI D8731 starting 16 weeks after UNX. Blood pressure was normalized with both treatments. After six months inulin clearance was not significant different, while proteinuria and prevalence of interstitial fibrosis were significantly reduced in all treatment groups. Immunohistochemical studies revealed an interstitial, periglomerular and perivascular increase of extracellular matrix proteins in all rats, but a markedly reduced expression of collagen I, IV and fibronectin after early and late treatment compared to untreated controls. We found a significant reduction of infiltrating macrophages and T-lymphocytes in all treated animals compared to untreated controls after 2, 4 and 6 months. Especially early treatment was associated with lower numbers of infiltrating cells. Both treatments reduced proliferation of tubular and interstitial cells. There were no striking differences with regard to nephroprotection between the ACE inhibitor and angiotensin II receptor blocker. These findings show that both treatments have beneficial effects on kidney structure and function. They suggest that both ACE inhibition and angiotensin II blockade decrease renal cell proliferation and suppress the infiltration of mononuclear cells that may trigger expression of extracellular matrix proteins and progressive nephrosclerosis.

Differential expression of apoptosis receptors on diffuse and intestinal type stomach carcinoma.

BACKGROUND: Intestinal and diffuse adenocarcinomas of the stomach differ in phenotypic properties, morphology, and growth behavior. Apoptosis (programmed cell death) is induced via specific cell-surface receptors (SC-1, Fas/APO-1/CD95) and coregulated by intracellular molecules (bcl-2, p53, etc.); the success of apoptotic processes is dependent on the expression of these signals. Differences in the expression of specific apoptosis receptors and intracellular-related signals might help to explain the molecular pathogenesis of these two types of stomach adenocarcinoma. METHODS: Immunohistochemical studies were performed on frozen sections of tumor tissue using human monoclonal antibody SC-1 and murine monoclonal antibodies Fas and p53, followed by peroxidase-coupled second antibodies. To determine binding of SC-1 and Fas antibodies to stomach carcinoma cells on the molecular level, Western blot analysis was performed with cell extract preparations from stomach carcinoma cells. To investigate functional apoptotic activity, MTT assays were performed with SC-1 and Fas antibodies on stomach carcinoma cells. RESULTS: On frozen sections intestinal type stomach carcinoma cells demonstrate little or no expression of SC-1 and Fas receptors (4 of 17 and 1 of 17, respectively). Diffuse type stomach carcinoma cells show just the opposite: greater than 50% express SC-1 and Fas at a high level (15 of 30 and 22 of 30, respectively). Normal stomach mucosa is negative with both antibodies. Expression of p53 is positively correlated with intestinal type carcinomas (11 of 17) but not with diffuse type (5 of 30). In functional studies MTT assay) the SC-1 and Fas antibodies react with stomach carcinoma by inducing apoptosis and inhibiting growth. On Western blot analysis of extracts from stomach carcinoma cells, SC-1 detects a protein of 50 kilodalton (kD) and Fas proteins of approximately 30, 45, and 60 kD. CONCLUSIONS: These data indicate that gastric carcinoma cells of the intestinal and diffuse type differ in their expression of the apoptotic receptors SC-1 and Fas and the tumor suppressor gene product p53. These new data on phenotypic differences support the hypothesis that these two types of stomach carcinoma do not only differ in morphology, growth pattern, and risk factors but also in genetic pathways.

Epidermal growth factor family and renal cell carcinoma: expression and prognostic impact.

OBJECTIVE: Expression and prognostic impact of some exponents of the epidermal growth factor (EGF) family in renal cell carcinoma (RCC) were examined. MATERIALS AND METHODS: EGF, transforming growth factor-alpha (TGF-alpha), EGF receptor (EGF-R), and c-erb B-2 were determined immunohistochemically in formalin-fixed paraffin-embedded tumor samples of 30 patients with locally confined RCCs. The prognostic significance of these growth factors and their receptors as well as of tumor stage and malignancy grade was examined with respect to survival and tumor recurrence by following up the fate of the patients after nephrectomy (mean follow-up time 5.2 years). RESULTS: The members of the EGF family and their receptors studied were expressed to a variable degree in all RCCs investigated. However, using log-rank tests in Kaplan-Meier plots only tumor stage (p < 0.0007) and malignancy grade (p < 0.007) but none of the growth factors or receptors studied (p > 0.05, respectively) exhibited prognostic significance with respect to both survival and disease-free period. On the contrary, there was a significant correlation between EGF and TGF-alpha (p < 0.001), EGF and EGF-R (p = 0.028), EGF-R and c-erb B-2 (p = 0.0009), and-inversely related-between TGF-alpha and tumor stage (p = 0.047) and between EGF-R and malignancy grade (p = 0.03). The coexpression of the factors studied also showed no prognostic relevance. CONCLUSION: The expression of these members of the EGF family seems not to bear evaluable prognostic information for clinical use in the case of RCC.

Effects of protease therapy in the remnant kidney model of progressive renal failure.

This study investigated whether protease treatment ameliorates the progressive course of chronic failure in the rat model of subtotal nephrectomy. Fourteen male Wistar rats underwent 5/6 nephrectomy, and were randomized into a control group (C, n = 7) given 2 ml of 0.9% NaCl intraperitoneally (i.p.) daily, and a study group (P, n = 7) treated with 12 mg Phlogenzym (combination of trypsin, bromelain, and rutosid) in 2 ml saline i.p. daily. After 6 weeks treatment, the Phlogenzym group showed lower proteinuria (C: 19.6 +/- 9.1 vs. 10.2 +/- 6.2 mg/24 h, p < 0.05). Endogenous creatinine clearance was higher (C: 192.3 +/- 99.4, P: 300.5 +/- 47.9 microliters/min per 100 g, p < 0.05), while plasma creatinine was decreased (C: 106.7 +/- 33.9, P: 76.0 +/- 6.3 mumol/l, p < 0.01). Blood urea nitrogen levels did not change, although urea clearance tended to a higher level in the protease-treated rats. Decreased renal formation of cytokines was reflected by a lower urinary excretion ratio of transforming growth factor (TGF)-beta/ creatinine (C: 0.363 +/- 0.183, P: 0.232 +/- 0.085 ng TGF-beta/mg creatinine, p < 0.05). Renal morphology revealed less infiltration of mononuclear cells and an amelioration of interstitial fibrosis as expressed by the volume index of the cortical region (C: 17.17 +/- 1.43; P: 12.3 +/- 0.5%, p < 0.001). In addition, the activities of lysosomal proteinases (cathepsin B, L + B, and H), which are decreased in the remnant kidney model of chronic renal failure, were significantly higher in the enzyme-treated group both in isolated glomeruli and proximal tubules. The body and kidney weight tended to be lower, probably due to a catabolic action of the enzymes. In summary, we provide evidence that protease treatment may be beneficial in a nonimmune mediated renal disease. Phlogenzym ameliorated the course of chronic renal failure in the rat model of subtotal nephrectomy and retarded the development of tubulointerstitial fibrosis. Decreased cytokine formation in the remnant kidney is supposed to play a key role.

Postoperative prognosis of pulmonary adenocarcinoma subtypes correlates with HLA-DR expression and the number of tumor-infiltrating cells.

Human pulmonary adenocarcinomas (AC) can be divided into two types with special morphologic and immunohistologic properties and a different number of tumor-infiltrating cells as shown by previous investigations. In the present study the relevance of this subdivision for patients' survival was investigated. 42 surgically resected pulmonary AC of stage I and II were subclassified using light and electron microscope. For immunohistologic phenotypization, reactions with monoclonal antibodies against HLA-DR, CD1 and CD3 were studied on fresh tumor specimens. Postoperative survival was evaluated after at least 24 months. AC of type I (N=23) with mucin production and ultrastructural properties of goblet cells showed almost no HLA-DR expression. Infiltration by CD1-positive dendritic cells Langerhans cells and CD3-positive T lymphocytes was significantly lower than in AC of type II (N=19), which expressed HLA-DR homogeneously and showed, ultrastructurally, Clara cell and/or type II pneumocyte properties. Patients' outcome was similar in stage I AC of both types: about 70% of patients were still alive after 24 months. However, significant differences were found between the two types in stage II AC with regional lymph node metastases: survival of patients with AC of type II corresponded roughly with stage I tumors (67%) but only 20% of patients with type I AC were still alive after 24 months. These results indicate that postoperative prognosis for patients with pulmonary AC of type II is more favourable than for mucinous AC of type I. This may be due to the homogeneous HLA-DR expression and higher number of immunologically competent tumor-infiltrating cells which possibly results in better tumor surveillance.

Expression of p53 and bcl-2 in primary locally confined renal cell carcinomas: no evidence for prognostic significance.

p53 tumor suppressor gene mutations are present in a wide variety of human cancers, and the bcl-2 gene product is considered to prevent apoptosis. However, the significance of these gene products for the aggressiveness of the tumor and correspondingly for the prognosis of patients with renal cell carcinoma (RCC) is unclear. The expression of p53 and bcl-2 gene products was studied immunohistochemically using formalin-fixed paraffinembedded tumor samples of 31 locally confined RCC of patients treated with radical nephrectomy. The significance of these 2 parameters, in addition to tumor stage and malignancy grade, was tested with regard to survival and time of no recurrence using Kaplan-Meier-plots by the log rank test or Tarone's test and the Cox multiple hazard regression analysis (mean follow-up 5.4 years). Only 5 of the 31 RCCs stained positively for p53 and only 2 showed positive bcl-2 staining of tumor cells. Tumor stage (P < 0.002) and malignancy grade (P < 0.007) were statistically significant prognostic parameters for both survival and disease-free period by univariate analysis. In contrast, the detection of either p53 (P > 0.67) or bcl-2 gene product (P > 0.28) had no prognostic impact. Also in the multivariate statistical analysis, neither of the 2 parameters i.e. p53 and bcl-2 expression significantly improved the prognostic impact of the conventional prognosticators stage and grade, if applied in addition. The expression of p53 and bcl-2 seems unimportant as a prognostic factor in locally confined RCCs.

[Coincidence of Pneumocystis carinii pneumonia and lung carcinoma in AIDS]. / Koinzidenz von Pneumocystic-carinii-Pneumonie und Lungenkarzinom bei AIDS

In a formerly drug-dependent patient of 35 years of age suffering from an advanced HIV infection there was a development within a period of a few months of rapid weight loss amounting to 12 kg, persistent subfebrile temperatures and progressive dyspnoea on exercise. The histological pattern obtained via bronchoscopy revealed not only pneumocystis carinii pneumonia, which had already been suspected clinically, but also a not very differentiated adenocarcinoma of the lung with lymphangiosis carcinomatosa. The patient died three months after tis diagnosis was established, which had been followed by the usual pneumocystosis therapy and palliative treatment with glucocorticoids.

Suppressing role of transforming growth factor-beta 1 on cathepsin activity in cultured kidney tubule cells.

Elevated expression and activity of transforming growth factor-beta 1 (TGF-beta 1) have been indicated in various renal diseases, implicating the potential involvement of this growth factor in the accumulation of extracellular matrix. To assess its potential role on protein turnover in tubule cells, we investigated in LLC-PK1 cells the effects of TGF-beta 1 on the activities of lysosomal cysteine proteinases cathepsins B, H, and L + B, which play a major role in the degradation of both cellular protein and extracellular matrix. The results show that 1-10 ng/ml TGF-beta 1 exerted inhibitory effects on cathepsin B and L + B activities, when applied to either the basolateral or apical membrane of these cells (basolateral side: B -23.2%, L + B -19.9%; apical side: B -28.2%, L + B -22.6%). Application of TGF-beta 1 to both sides enhanced suppression of the enzyme activities (B -37.8%, L + B -37.4%). This suppression of cathepsin activities was accompanied by a reduction of cellular protein degradation rate by 20.0% after 24 h and 51.7% after 48 h. Furthermore, TGF-beta 1 stimulated cellular protein synthesis by 50.0% after 48 h. The combined effects on protein turnover resulted in cellular hypertrophy: increases of both protein content and cell size after 48 h. Concerning the underlying mechanism, TGF-beta 1 did not induce a rise in intracellular Ca2+ concentration nor did Ca2+ channel blocker verapamil (10(-6) M) ameliorate the TGF-beta 1-induced inhibition of cathepsin activities. However, TGF-beta 1 raised the pH in lysosomes, which obviously impaired the acidic cysteine proteinases. In conclusion, the TGF-beta 1-induced cellular hypertrophy is caused by both enhanced protein synthesis and reduced protein breakdown. Suppression of cathepsin B and L + B activities mediated probably by an alkalinization in lysosomes is involved in the decreased protein degradation.

Surfactant protein gene expression in metastatic and micrometastatic pulmonary adenocarcinomas and other non-small cell lung carcinomas: detection by reverse transcriptase-polymerase chain reaction.

Reverse transcriptase (RT)-PCR with primers specific for surfactant protein A (SP-A), B (SP-B), C (SP-C), and D (SP-D) genes was applied to detect metastatic non-small cell lung carcinomas. Forty-one paratracheal and subcarinal lymph nodes obtained from 41 patients with non-small cell lung carcinomas, 11 lymph nodes from 11 patients with extrapulmonary adenocarcinomas, and eight control lymph nodes from patients without cancer were analyzed using RT-PCR. PCR products corresponding to SP-B gene products were found in all eight control lymph nodes, offering evidence of SP-B gene expression in cells of lymphatic tissue. SP-A, SP-C, and/or SP-D transcripts were detected in 11 (84.6%) of 13 lymph nodes with histologically identifiable metastases of pulmonary adenocarcinomas and in 10 (55.5%) of 18 lymph nodes that were tumor free on routine histological examination. These findings provide evidence of micrometastatic nodal involvement which remains undetectable by conventional light microscopy but can be evaluated by surfactant RT-PCR. Gene expression of SP-A and SP-C was restricted to metastatic pulmonary adenocarcinomas but SP-D gene activity has been also detected in two of four metastases of pulmonary large cell carcinomas, one adenosquamous carcinoma, and nine extrapulmonary adenocarcinomas as well.

Importance of different CD44v6 expression in human gastric intestinal and diffuse type cancers for metastatic lymphogenic spreading.

In 42 human gastric adenocarcinomas of intestinal (n = 25) and diffuse types (n = 17) the expression of CD44v6 splice variants was investigated immunohistochemically and compared with the pattern of lymphogenic tumor spreading. Distinct differences were observed between the two cancer types: 92% of intestinal-type tumors expressed CD44v6 as in the intestinal metaplasia in chronic atrophic gastritis, while v6 expression occurred in only 17% of diffuse-type cancers. The analysis of RNA expression confirmed the immunohistochemical data. Intestinal-type cancers yielded a much more complex pattern of amplification products hybridizing to exon v6 than did normal mucosa, whereas diffuse-type tumors did not express exon v6. Also the pattern of lymphogenic spreading was quite different between the two cancer types: in diffuse-type tumors only a sinus carcinosis without CD44v6 expression was observed in a significantly higher number of lymph nodes than in intestinal-type cancers, which showed in particular infiltrative lymph node metastases always with CD44v6 expression as in the primary tumors. When infiltrative lymph node invasion occurred in v6-negative diffuse-type cancers, v6 neoexpression was also demonstrable in the lymph node metastases. Additionally, the number of infiltrative lymphogenic metastases increased with more extensive v6 expression in primary gastric cancers of both types. These data suggest that the expression of CD44v6 isoform is important for the infiltrative spreading of tumor cells into lymph nodes. Additionally, the phenotypic similarities in v6 expression between intestinal metaplasia and intestinal-type cancers, but not of tumors of diffuse type, may support the Correa hypothesis.

Apoptosis of stomach carcinoma cells induced by a human monoclonal antibody.

BACKGROUND: Although stomach carcinoma is estimated to be one of the most frequent cancers worldwide, still little is known about the immunity of patients with stomach cancer. Humoral tumor immunity has been studied by isolating B cells of patients with cancer to characterize the activity of such antibodies on tumor cells. Apoptosis, programmed cell death, explains the suicide of cells by fragmentation of DNA, cell shrinkage and dilation of endoplasmatic reticulum, followed by cell fragmentation and formation of membrane vesicles called apoptotic bodies. Apoptosis serves to remove unwanted, damaged, or dangerous, e.g., precancerous cells. METHODS: The human monoclonal antibody SC-1 was isolated from a patient with a signet ring cell carcinoma of the stomach by fusion of spleen lymphocytes to the heteromyeloma SPM4-0. The antibody was tested for growth-inhibiting effects in vitro in soft agar assays, in 3-H thymidine uptake experiments, and in a mitochondrial enzymatic activity assay. In vivo intraperitoneal tumor growth was investigated in nu-nu mice. RESULTS: The immunoglobulin M (lambda) antibody identifies a molecule with a molecular weight of approximately 49 kilodaltons in stomach carcinoma cells. No reactivity was observed with carcinomas of other origins, melanomas, lymphomas, or normal tissue. When tested in vitro, the antibody inhibited tumor cell growth in cell culture and soft agar. In vivo growth of stomach carcinoma cells in nu-nu mice was reduced when the antibody was injected after the tumor cells. Ultrastructural and functional studies revealed that the SC-1 antibody induced apoptosis of tumor cells. CONCLUSION: The human monoclonal antibody SC-1 described here inhibited growth of stomach carcinoma cells in vitro and in vivo by inducing apoptosis, and may, therefore, be valuable for treating patients with stomach carcinoma.