Immuno-PCR: very sensitive antigen detection by means of specific antibody-DNA conjugates

An antigen detection system, termed immuno-polymerase chain reaction (immuno-PCR), was developed in which a specific DNA molecule is used as the marker. A streptavidin-protein A chimera that possesses tight and specific binding affinity both for biotin and immunoglobulin G was used to attach a biotinylated DNA specifically to antigen-monoclonal antibody complexes that had been immobilized on microtiter plate wells. Then, a segment of the attached DNA was amplified by PCR. Analysis of the PCR products by agarose gel electrophoresis after staining with ethidium bromide allowed as few as 580 antigen molecules (9.6 x 10(-22) moles) to be readily and reproducibly detected. Direct comparison with enzyme-linked immunosorbent assay with the use of a chimera-alkaline phosphatase conjugate demonstrates that enhancement (approximately x 10(5)) in detection sensitivity was obtained with the use of immuno-PCR. Given the enormous amplification capability and specificity of PCR, this immuno-PCR technology has a sensitivity greater than any existing antigen detection system and, in principle, could be applied to the detection of single antigen molecules.

Expression status of p16 protein is associated with human papillomavirus oncogenic potential in cervical and genital lesions

The p16 protein (p16) is a cyclin-dependent kinase (CDK) inhibitor that decelerates the cell cycle by inactivating the CDKs that phosphorylate retinoblastoma (Rb) protein. Recent biological studies have revealed that p16 expression is markedly influenced by the status of Rb expression, and p16 overexpression has been demonstrated in cervical cancers because of functional inactivation of Rb by human papillomavirus (HPV) E7 protein. To clarify the relationship between p16 overexpression and HPV infection in cervical carcinogenesis, immunohistochemical analysis of p16 and detection of HPV by in situ hybridization and polymerase chain reaction were performed on 139 formalin-fixed and paraffin-embedded samples of cervical and genital condylomatous and neoplastic lesions. Marked overexpression of p16 protein, ie, diffuse and strong immunostaining, was observed in all cervical cancers and preneoplastic lesions with infection by high- and intermediate-risk HPVs, ie, subtypes 16, 18, 31, 33, 52, and 58. Condylomata acuminata and low-grade squamous intraepithelial lesions with infection by low-risk HPV such as HPV-6/11 showed focal and weak immunohistochemical staining for p16. Our results clearly showed that the mode of p16 expression in lesions with high- and intermediate-risk HPVs differed from its expression in lesions with low-risk HPVs and thus might be attributable to differences in functional inactivation of Rb protein by different HPVs.

A class-wide phylogenetic assessment of Dothideomycetes

We present a comprehensive phylogeny derived from 5 genes, nucSSU, nucLSU rDNA, TEF1, RPB1 and RPB2, for 356 isolates and 41 families (six newly described in this volume) in Dothideomycetes. All currently accepted orders in the class are represented for the first time in addition to numerous previously unplaced lineages. Subclass Pleosporomycetidae is expanded to include the aquatic order Jahnulales. An ancestral reconstruction of basic nutritional modes supports numerous transitions from saprobic life histories to plant associated and lichenised modes and a transition from terrestrial to aquatic habitats are confirmed. Finally, a genomic comparison of 6 dothideomycete genomes with other fungi finds a high level of unique protein associated with the class, supporting its delineation as a separate taxon.

Carbon monoxide: an endogenous modulator of sinusoidal tone in the perfused rat liver

Heme oxygenase is a heme-oxidizing enzyme which generates biliverdin and carbon monoxide (CO). The present study was designed to elucidate whether CO endogenously produced by this enzyme serves as an active vasorelaxant in the hepatic microcirculation. Microvasculature of the isolated perfused rat liver was visualized by dual-color digital microfluorography to alternately monitor sinusoidal lining and fat-storing Ito cells. In the control liver, the CO flux in the venous effluent ranged at 0.7 nmol/min per gram of liver. Administration of a heme oxygenase inhibitor zinc protoporphyrin IX (1 microM) eliminated the baseline CO generation, and the vascular resistance exhibited a 30% elevation concurrent with discrete patterns of constriction in sinusoids and reduction of the sinusoidal perfusion velocity. The major sites of the constriction corresponded to local sinusoidal segments colocalized with Ito cell which were identified by imaging their vitamin A autofluorescence. The increase in the vascular resistance and sinusoidal constriction were attenuated significantly by adding CO (1 microM) or a cGMP analogue 8-bromo-cGMP (1 microM) in the perfusate. From these findings, we propose that CO can function as an endogenous modulator of hepatic sinusoidal perfusion through a relaxing mechanism involving Ito cells.

Extrathoracic solitary fibrous tumors: their histological variability and potentially aggressive behavior

The histological variability of solitary fibrous tumors may contribute to the difficulty in diagnosing these neoplasms, especially when they arise in extrathoracic sites. Like intrathoracic lesions, the behavior of extrathoracic solitary fibrous tumors is currently unpredictable because these types of tumor have only recently been recognized. This study therefore was undertaken to examine the clinical behavior and histological, immunohistochemical, and ultrastructural features of 24 extrathoracic solitary fibrous tumors with long-term follow-up. The patients comprised 10 men and 14 women, between 30 and 85 years of age (mean, 51 years). Ten tumors were located in the retroperitoneum or pelvis, 5 in the trunk, 4 in the extremities, 2 in the orbital region, and 1 each in the kidney, uterine cervix, and meninges. All of the tumors showed a classic morphological appearance, diffuse and strong immunoreactivity for both vimentin and CD34, and variable reactivity for bcl-2. All 7 cases examined ultrastructurally contained fibroblasts and myofibroblasts. Six tumors contained multinucleated giant cells, and in 4 cases these lined pseudovascular spaces with mononuclear cells, thus resembling giant cell angiofibroma and giant cell fibroblastoma. Other potentially similar spindle cell neoplasms mixed with adipose tissue, such as dendritic fibromyxolipoma, lipomatous hemangiopericytoma, cellular angiofibroma, and spindle cell lipoma, were considered in the differential diagnosis. One tumor displayed atypical histological features in the form of increased cellularity and nuclear pleomorphism, but this patient has remained free of disease for 14 years. Another 2 patients developed local recurrences at 6 months and 5 years, and a further patient developed pulmonary metastases that were diagnosed after 7 years. These tumors lacked any atypical histological features in the primary lesions. No patient has so far died of the disease. In conclusion, most extrathoracic solitary fibrous tumors appear to pursue a benign course, although, because some have the potential to recur or metastasize, careful long-term follow-up is necessary for all patients.

Lymph node metastasis from early gastric cancer: endoscopic resection of tumour

The clinicopathological features of 748 solitary early gastric cancers were examined with regard to lymph node metastasis. Among several factors, only depth of invasion and tumour size correlated significantly with node involvement. Tumours which satisfy the following criteria may not metastasize to lymph nodes: (1) confined to the mucosa; (2) less than 1.5 cm in diameter; (3) macroscopically elevated; (4) macroscopically depressed, without intramural ulcers or ulcer scars (endoscopically, no fold convergence); and (5) histologically differentiated. With a recently developed endoscopic technique small gastric tumours can safely be resected. The cut margin and depth of tumour invasion can be verified histologically in the specimen. If an endoscopically removed tumour satisfies the above criteria, further surgical intervention may be optional as the outcome of endoscopic resection is comparable to that of radical surgery in the absence of node involvement.

Aggressive preoperative management and extended surgery for hilar cholangiocarcinoma: Nagoya experience

From 1977 to 1997, surgical resection was possible in 142 (80%) of 177 patients with hilar cholangiocarcinoma after relieving jaundice by single or multiple percutaneous transhepatic biliary drainage followed by percutaneous transhepatic cholangioscopy and/or percutaneous trans-hepatic portal vein embolization. Curative resection was possible in 108 (61%) of the 142 patients, and 100 of these patients underwent various types of hepatectomy with caudate lobectomy for a 30-day operative mortality rate of 6% and 9% hospital mortality. Combined portal vein resection was carried out in 43 cases including 41 hepatectomies and 2 bile duct resections. Hepatopancreatoduodenectomy was performed in 16 patients. Cancer recurrence was observed in 58 of the 108 patients undergoing curative resection. The 3-, 5-, and 10-year survival rates for 100 patients undergoing curative hepatectomy and 8 with curative bile duct resection were 43%, 26%, and 19%; and 31%, 16%, and 0%, respectively; those for 40 patients with positive lymph node metastasis, 84 with perineural invasion, and 43 with combined portal vein resection were 27%, 14%, and 7%; 34%, 21%, and 13%; and 18%, 6%, and 0%, respectively. These survival rates are significantly better than those for 35 patients with unresectable cancer. Curative resection after aggressive preoperative management is recommended as a reasonable surgical approach to hilar cholangiocarcinoma.

Recurrence of early gastric cancer. Follow-up of 1475 patients and review of the Japanese literature

BACKGROUND

The outcome of surgical treatment for early gastric cancer (EGC) generally is considered to be satisfactory. Although a small percentage of patients experience disease recurrence, the absolute number of such instances is too small for assessment of risk factors.

METHODS

The authors investigated the follow-up records of 1475 patients with EGC treated at the National Cancer Center, Tokyo, with special reference to cancer recurrence. In addition, 20 Japanese reports on this subject were reviewed.

RESULTS

Excluding operative deaths and patients with noncurative operations, 20 (1.4%) patients died of recurrent disease. The death rate associated with other causes (6.6%), including other malignant diseases, surpassed that associated with disease recurrence. Late recurrence (after 5 years) was seen in seven patients. By combining the data of patients reported in 20 articles in the literature, the authors estimated a recurrence rate for EGC of at least 1.9%, exclusive of cancers arising in the gastric stump. The incidence of recurrence was significantly higher in submucosal (3.6%), node-positive (10.7%), and histologically differentiated carcinomas (2.3%) than in mucosal, node-negative, and undifferentiated groups, respectively. Analysis of 123 instances of recurrent disease, the details of which had been reported, revealed that hematogenous metastasis was the most common mode of recurrence. The mean survival period of patients with recurrent disease was 40 months, and 23% of patients died more than 5 years after surgery.

CONCLUSION

It is rare for EGC to recur, even in patients with tumors with a comparatively high risk of recurrence. Long-term follow-up of patients with positive nodes for hematogenous spread might facilitate early detection of disease recurrence.

Validation of the 8th Edition of the AJCC TNM Staging System for Gastric Cancer using the National Cancer Database

BACKGROUND

The 8th edition AJCC gastric cancer staging manual was refined using Japanese and Korean data from the International Gastric Cancer Association (IGCA). This study evaluated the eighth edition's validity for U.S.

POPULATIONS

METHODS

National Cancer Database (NCDB) was used to obtain data on gastric cancer patients diagnosed from 2004 to 2008 who underwent surgery and to examine differences in stage grouping and survival between AJCC 7th and 8th editions. Discrimination of models derived from NCDB and IGCA data was compared.

RESULTS

Of 12,041 patients, median age was 65, 57.6% were male, median lymph nodes retrieved was 2 (0-76), 30.9% underwent distal/partial gastrectomy, and 49.8% received no adjuvant treatment. The 8th edition differed in that T1-T3 disease was upstaged with N3b, T4aN3a was downstaged from IIIC to IIIB, and T4bN0 and T4aN2 were downstaged from IIIB to IIIA. These changes resulted in increased patients in IIIA (1436 in the 7th edition to 2310 in the 8th) and IIIB (1737-1896) and decreased in IIIC (2100-1067). This also resulted in lower median survival for IIIA (28.7-25.0 months), IIIB (19.6-17.4), IIIC (13.7-11.8). The concordance index for the 8th edition applied to NCDB data was 0.719 [95% confidence interval (CI) 0.703-0.734), which is comparable to that for the 8th edition developed from IGCA data (0.775, 95% CI 0.770-0.780) and the 7th edition applied to NCDB data (0.720, 95% CI 0.704-0.735).

CONCLUSIONS

The 8th edition is valid for U.S. populations, showing clear separation of data with preservation of group order.

Oligonucleotide-directed self-assembly of proteins: semisynthetic DNA--streptavidin hybrid molecules as connectors for the generation of macroscopic arrays and the construction of supramolecular bioconjugates

Modified biomolecules were used for the non-covalent assembly of novel bioconjugates. Hybrid molecules were synthesized from short single-stranded DNA and streptavidin by chemical methods using a heterobispecific crosslinker. The covalent attachment of an oligonucleotide moiety to streptavidin provides a specific recognition domain for a complementary nucleic acid sequence, in addition to the four native biotin-binding sites. These bispecific binding capabilities allow the hybrid molecules to serve as versatile connectors in a variety of applications. Bifunctional constructs have been prepared from two complementary hybrid molecules, each previously conjugated to biotinylated immunoglobulin G or alkaline phosphatase. The use of nucleic acid sequences as a template for the formation of an array of proteins is further demonstrated on two size scales. A macroscopic DNA array on a microtiter plate has been transformed into a comparable protein chip. A nano-scale array was made by hybridizing DNA-tagged proteins to specific positions along a RNA or DNA sequence. The generation of supramolecular bioconjugates was shown by quantitative measurements and gel-retardation assays.

Risk factors for lymph node metastasis from intramucosal gastric carcinoma

BACKGROUND

Although regional lymph node metastasis from intramucosal early gastric carcinoma (EGC) is rare, it is very important to clarify the characteristics of patients having lymph nodal metastases in order to determine appropriate therapy.

METHODS

The authors investigated 1196 patients with solitary intramucosal EGC who underwent resection at the National Cancer Center Hospital in Tokyo, with special reference to lymph node metastases. Eight clinicopathologic factors (age, sex, tumor: size, location, macroscopic type, histologic type, histologic ulceration of the tumor, and lymphatic vessel invasion) were investigated by univariate and multivariate analyses for their possible relationship to lymph node metastasis.

RESULTS

Lymph node metastases were found in 43 patients (3.5%). Univariate analysis revealed that younger age (< 57 years), macroscopic depressed type, larger tumor size (> or= 30 mm), undifferentiated histologic type, histologic ulceration of the carcinoma, and lymphatic vessel invasion had a significant association with regional lymph node metastasis. Multivariate analysis revealed that lymphatic vessel invasion, histologic ulceration of the tumor, and larger size (> or = 30 mm) were independent risk factors for regional lymph node metastasis. The incidence of lymph node metastasis from intramucosal EGC negative for these 3 risk factors was only 0.36% (1 in 277 patients).

CONCLUSIONS

Lymphadenectomy is unnecessary for patients with small intramucosal EGC with neither histologic ulceration of the tumor nor lymphatic vessel invasion because the incidence of regional lymph node metastasis is extremely low in those patients. The therapeutic options for such patients would be local resection or endoscopic resection.

Lymph node metastasis from hilar cholangiocarcinoma: audit of 110 patients who underwent regional and paraaortic node dissection

OBJECTIVE

To assess the status of the regional and paraaortic lymph nodes in hilar cholangiocarcinoma and to clarify the efficacy of systematic extended lymphadenectomy.

SUMMARY BACKGROUND DATA

There have been no studies in which regional and paraaortic lymphadenectomies for hilar cholangiocarcinoma have been routinely performed. Therefore, the metastasis rates to the regional and paraaortic nodes, the mode of lymphatic spread, and the effect of extended lymph node dissection on survival remain unknown.

METHODS

This study involved 110 patients who underwent surgical resection for hilar cholangiocarcinoma with lymph node dissection including both the regional and paraaortic nodes. A total of 2,652 nodes retrieved from the surgical specimens were examined microscopically.

RESULTS

Of the 110 patients, 52 (47.3%) had no involved nodes, 39 (35.5%) had regional lymph node metastases, and 19 (17.3%) had regional and paraaortic node metastases. The incidence of positive nodes was significantly higher in the patients with pT3 disease than in those with pT2 disease. The pericholedochal nodes were most commonly involved (42.7%), followed by the periportal nodes (30.9%), the common hepatic nodes (27.3%), and the posterior pancreaticoduodenal nodes (14.5%). The celiac and superior mesenteric nodes were rarely involved. The 3-year and 5-year survival rates were 55.4% and 30.5% for the 52 patients without involved nodes, 31.8% and 14.7% for the 39 patients with regional node metastases, and 12.3% and 12.3% for the 19 patients with paraaortic node metastases, respectively. Of the 19 patients with positive paraaortic nodes, 7 had no macroscopic evidence of paraaortic disease on intraoperative inspection. The survival in this group was significantly better than in the remaining 12 patients.

CONCLUSION

The paraaortic nodes and the regional nodes are frequently involved in advanced hilar cholangiocarcinoma. Whether extended lymph node dissection provides a survival benefit requires further study. However, the fact that long-term survival is possible despite pN2 or pM1 disease encourages the authors to perform an aggressive surgical procedure with extended lymph node dissection in selected patients with hilar cholangiocarcinoma.

High expression of Toll-like receptor 4/myeloid differentiation factor 88 signals correlates with poor prognosis in colorectal cancer

Background:

The Toll-like receptor (TLR) 4 signalling pathway has been shown to have oncogenic effects in vitro and in vivo. To demonstrate the role of TLR4 signalling in colon tumourigenesis, we examined the expression of TLR4 and myeloid differentiation factor 88 (MyD88) in colorectal cancer (CRC).

Methods:

The expression of TLR4 and MyD88 in 108 CRC samples, 15 adenomas, and 15 normal mucosae was evaluated by immunohistochemistry, and the correlations between their immunoscores and clinicopathological variables, including disease-free survival (DFS) and overall survival (OS), were analysed.

Results:

Compared with normal mucosae and adenomas, 20% cancers displayed high expression of TLR4, and 23% cancers showed high expression of MyD88. The high expression of TLR4 and MyD88 was significantly correlated with liver metastasis (P=0.0001, P=0.0054). In univariate analysis, the high expression of TLR4 was significantly associated with shorter OS (hazard ratio (HR): 2.17; 95% confidence interval (95% CI): 1.15–4.07; P=0.015). The high expression of MyD88 expression was significantly associated with poor DFS and OS (HR: 2.33; 95% CI: 1.31–4.13; P=0.0038 and HR: 3.03; 95% CI: 1.67–5.48; P=0.0002). The high combined expression of TLR4 and MyD88 was also significantly associated with poor DFS and OS (HR: 2.25; 95% CI: 1.27–3.99; P=0.0053 and HR: 2.97; 95% CI: 1.64–5.38; P=0.0003). Multivariate analysis showed that high expressions of TLR4 (OS: adjusted HR: 1.88; 95% CI: 0.99–3.55; P=0.0298) and MyD88 (DFS: adjusted HR: 1.93; 95% CI: 1.01–3.67; P=0.0441; OS: adjusted HR: 2.25; 95% CI: 1.17–4.33; P=0.0112) were independent prognostic factors of OS. Furthermore, high co-expression of TLR4/MyD88 was strongly associated with both poor DFS and OS.

Conclusion:

Our findings suggest that high expression of TLR4 and MyD88 is associated with liver metastasis and is an independent predictor of poor prognosis in patients with CRC.

Pancreas-preserving total gastrectomy for proximal gastric cancer

Lymph node (LN) dissection along the upper border of the pancreas is one of the essential parts of curative surgery for gastric cancer, and the distal portion of the pancreas was frequently resected for complete removal of LNs along the splenic artery. However, pancreatic juice leakage, subphrenic abscess, and postoperative diabetes were common complications in patients treated by pancreatic resection. To avoid these problems a new surgical procedure, the pancreas-preserving operation, was developed by Maruyama in 1979. We found that lymphatic channels from the stomach did not flow into the pancreas parenchyma, and that the spleen, splenic artery, and fatty connective tissue including nodes could be removed completely without dissection of the pancreas parenchyma and splenic vein. The preserved pancreas receives its arterial blood supply through the transverse pancreatic artery, and its preservation prevents postoperative diabetes. A total of 299 patients were treated by this procedure. The operative mortality rate was 0.3%, the hospital death rate 1.6%, and the surgical complications rate 19.6%. The cumulative 5-year survival rate for those with stage II was 70.5% and for those with stage III 54.1%. These results were superior to those of the pancreas resection group.

Phase II study of neoadjuvant chemotherapy and extended surgery for locally advanced gastric cancer

BACKGROUND

Locally advanced gastric cancer with extensive lymph node metastasis is usually considered unresectable and so treated by chemotherapy. This trial explored the safety and efficacy of preoperative chemotherapy followed by extended surgery in the management of locally advanced gastric adenocarcinoma.

METHODS

Patients with gastric cancer with extensive lymph node metastasis received two or three 28-day cycles of induction chemotherapy with irinotecan (70 mg/m(2) on days 1 and 15) and cisplatin (80 mg/m(2) on day 1), and then underwent gastrectomy with curative intent with D2 plus para-aortic lymphadenectomy. Primary endpoints were 3-year overall survival and incidence of treatment-related death.

RESULTS

The study was terminated because of three treatment-related deaths when 55 patients had been enrolled (mortality rate above 5 per cent). Two deaths were due to myelosuppression and one to postoperative complications. Clinical response and R0 resection rates were 55 and 65 per cent respectively. The pathological response rate was 15 per cent. Median overall survival was 14.6 months and the 3-year survival rate 27 per cent.

CONCLUSION

This multimodal treatment of locally advanced gastric cancer provides reasonable 3-year survival compared with historical data, but at a considerable cost in terms of morbidity and mortality.

A simple preparation of half N-acetylated chitosan highly soluble in water and aqueous organic solvents

A simple and improved method of preparing highly soluble chitosan (half N-acetylated chitosan) was developed using a series of chitosan samples of low molecular weights, and the solubility of the half N-acetylated chitosan in water and organic solvents was investigated in detail. To reduce the molecular weight, chitosan was treated with NaBO3 under the condition that chitosan was homogeneously dissolved in aqueous acetic acid. Weight-average molecular weights of the obtained chitosan samples were determined using a size-exclusion chromatography system equipped with a low-angle laser light-scattering photometer. Each chitosan sample was then N-acetylated with acetic anhydride under the condition that chitosan was homogeneously dissolved in aqueous acetic acid again. The water solubility of the half N-acetylated chitosan thus prepared increased with decreasing molecular weight. From 1H NMR spectroscopy, it was suggested that the sequence of N-acetylglucosamine and glucosamine residues was random. The solubility of the half N-acetylated chitosan of low molecular weight was rather high even in aqueous dimethylacetamide and dimethylsulfoxide.

Oxidative stress measurement by in vivo electron spin resonance spectroscopy in rats with streptozotocin-induced diabetes

Enhanced oxidative stress in diabetic patients may contribute to the pathogenesis of diabetic angiopathy. We have recently developed a method to determine the electron spin resonance (ESR, electron paramagnetic resonance; EPR) of reactive oxygen species and free radicals in vivo, using the nitroxide derivative, carbamoyl-PROXYL as a probe. In this study, diabetes was induced in Wistar rats by streptozotocin (STZ) injection (65 mg/kg, body weight, intravenously). Two, 4, and 8 weeks later, the animals received carbamoyl-PROXYL (300 nmol/g, intravenously), and ESR was measured at the upper abdominal level at a frequency of 300 MHz. The intensity of the carbamoyl-PROXYL ESR signal decreased gradually after the injection, and the spin clearance rate was determined over the first 5 min. At all time points, the spin clearance rate was significantly greater in the diabetic rats than in control rats. Moreover, the spin clearance rate in the diabetic rats was significantly correlated with urinary malondialdehyde (MDA) levels, which serve as a marker for lipid peroxidation. Daily treatment with 4 units neutral protamin Hagedorn (NPH) insulin for 4 weeks reduced the spin clearance rate in the diabetic rats. Simultaneous injection of carbamoyl-PROXYL and superoxide dismutase reduced the spin clearance rate in the diabetic rats in a dose-dependent manner. Injection of the antioxidant alpha-tocopherol (40 mg/kg, intraperitoneally) for 2 weeks restored the spin clearance rate in the diabetic rats without concomitant glycaemic restoration. These results suggest that a diabetic state enhances the generation of free radicals in vivo, and that both glycaemic control and antioxidant treatment can reduce this oxidative stress. Non-invasive in vivo ESR measurement may be useful for evaluating oxidative stress in diabetes.

Identification of risk factors for the development of complications following extended and superextended lymphadenectomies for gastric cancer

BACKGROUND

Extended lymphadenectomy for gastric carcinoma has been associated with high mortality and morbidity rates in several multicentre randomized trials.

METHODS

Using data from 523 patients registered for a prospective randomized trial comparing extended (D2) and superextended (D3) lymphadenectomies, risk factors for overall complications and major surgical complications (anastomotic leakage, intra-abdominal abscess and pancreatic fistula) were identified by multivariate logistic regression analysis.

RESULTS

Mortality and morbidity rates were 0.8 per cent (four of 523) and 24.5 per cent (128 of 523) respectively. Pancreatectomy (relative risk 5.62 (95 per cent confidence interval (c.i.) 1.94 to 16.27)) and prolonged operating time (relative risk 2.65 (95 per cent confidence interval 1.34 to 5.23)) were the most important risk factors for overall complications. A body mass index of 25 kg/m2 or above, pancreatectomy and age greater than 65 years were significant predictors of major surgical complications.

CONCLUSION

Pancreatectomy should be reserved for patients with stage T4 disease. Age and obesity should be considered when planning surgery.

Growth hormone-releasing hormone-producing tumors: clinical, biochemical, and morphological manifestations

This paper has reviewed current knowledge of clinical, biochemical, and morphological manifestations of extracranial GRH-producing tumors. Excessive GRH release stimulates pituitary somatotrophs causing elevation of blood GH levels and acromegaly. In some patients with GRH-containing tumor, blood GH concentrations are normal and no acromegaly develops. GRH-producing tumors associated with acromegaly are rare. Based on a critical analysis of the literature, 30 tumors are accepted as definitive. They possess unique features: occurrence in young age, female preponderance, foregut derivation, benign biological behavior, small secretory granules, and frequent association with MEN type I syndrome. The pancreas and lung are common primary sites. GRH-containing tumors unassociated with acromegaly include those of gut and thymus, small cell carcinoma of lung, and medullary carcinoma of thyroid. Several tumors are plurihormonal. In contrast to somatotroph adenoma seen in patients with classical acromegaly, the hypophysial lesion represents somatotroph hyperplasia in acromegalic patients with GRH-producing tumor. This finding indicates that GRH not only increases somatotroph secretory activity but causes somatotroph proliferation. Studies of GRH-producing tumors are of fundamental importance in obtaining a deeper insight into endocrine activity of pituitary somatotrophs and the pathogenesis of GH-secreting pituitary adenomas associated with acromegaly; the importance of GRH in the etiology of acromegaly is still unresolved. The relationship between GRH-secreting tumors and MEN type I syndrome is controversial; further studies are required to elucidate whether they represent two distinct entities or whether GRH-producing tumors accompanied by acromegaly are only forme fruste manifestations of MEN type I syndrome.

The pituitary gland in pregnancy: a clinicopathologic and immunohistochemical study of 69 cases

A histologic and immunocytochemical study of 69 autopsy-obtained pituitaries from women who died during pregnancy, after abortion, or in the postpartum period revealed an accumulation of large chromophobic to slightly acidophilic and periodic acid-Schiff-negative pregnancy cells that were immunoreactive for prolactin but not for other pituitary hormones. This increase in the number of prolactin cells was confirmed by cell counts. Thus, pregnancy cells are capable of prolactin production. The finding of mitotic figures in such cells supports the view that they arise by multiplication from preexisting prolactin cells. With use of "mirror section" techniques, no mammosomatotrophs (cells immunoreactive for growth hormone and prolactin) were identified. Hyperplasia of prolactin cells was evident at 1 month of pregnancy and gradually disappeared within several months after delivery or abortion; the process of involution seemed to be retarded in the one lactating patient investigated. In some pituitaries, the accumulation of prolactin cells was so extensive that the hyperplastic foci resembled microadenomas. Another striking change in the pituitaries of pregnant women was appreciable reduction of immunostaining of gonadotropic cells, a process that was reversible as soon as 1 month after delivery. Among the 69 pituitaries studied, 8 noninvasive microadenomas (12%) were encountered (7 contained prolactin only and 1 was plurihormonal). Prolactin-producing adenomas were no more numerous or larger than were similar tumors encountered in nonpregnant women or normal men; thus, pregnancy neither initiates formation of pituitary adenomas nor accelerates their growth. In the pituitaries that harbored prolactin-producing adenomas, massive pregnancy cell hyperplasia was evident outside the tumor; thus, prolactin production by adenoma cells did not seem to suppress the proliferation of prolactin-containing pregnancy cells.

Clinicopathological features of growth hormone-producing pituitary adenomas: difference among various types defined by cytokeratin distribution pattern including a transitional form

Pituitary adenomas producing almost exclusively growth hormones (GH) have been ultrastructurally classified into two distinct types: densely granulated somatotroph (DG) adenomas and sparsely granulated (SG) adenomas. Fibrous body (FB), an intracytoplasmic globular aggregation of cytokeratin (CK) filaments, is a hallmark of SG adenomas. Under light microscope, FB could be identified by CK immunohistochemistry as a dot-pattern immunoreaction versus a perinuclear pattern for cells without FB. However, it has been noted that numerous adenomas contain mixed populations of the two patterns. To clarify clinicopathological characteristics of the adenomas with mixed populations ("intermediate type" adenomas) and to confirm clinicopathological differences between strictly defined DG-type and SG-type adenomas, we performed this study on 104 GH cell adenomas. Having segregated "intermediate-type" adenomas (26 cases), we found significant differences between typical DG-type (47 cases) and SG-type adenomas (31 cases); SG-type adenomas had younger ages (44 vs. 50), higher frequency of macroadenomas (86% vs. 58%), invasiveness (65% vs. 38%), advanced grades (3 or 4) in Knosp's classification (50% vs. 24%), and weaker immunoreaction for GH, beta-TSH, alpha-subunit, E-cadherin, and beta-catenin. Clinicopathological characteristics of "intermediate-type" adenomas were identical to those of DG-type adenomas. These findings confirm that SG-type adenoma is a distinct section of GH cell adenomas with special properties and biological behavior, and suggest that intermediate-phenotype adenomas are enrolled in DG-type adenomas. Special properties and biological behavior of SG-type adenomas may appear after the majority of tumor cells possess a fully developed fibrous body.

Immunohistochemical demonstration of EMA/Glut1-positive perineurial cells and CD34-positive fibroblastic cells in peripheral nerve sheath tumors

To clarify the cellular composition of various peripheral nerve tumorous lesions (traumatic neuroma, 5 cases; schwannoma, 10 cases; neurofibroma, 14 cases; perineurioma, 3 cases; conventional malignant peripheral nerve sheath tumor (MPNST), 7 cases; perineurial MPNST, 4 cases), expression of several markers specific to nerve sheath cells, including glucose transporter protein 1 (Glut1) and CD34, were immunohistochemically investigated with highly sensitive detection methods. In normal nerves and neuromas, perineuriums were positive for Glut1 as well as for epithelial membrane antigen (EMA), and there were some CD34-positive fibroblast-like cells in the endoneurium. Schwannomas consisted principally of S-100 protein-positive Schwann cells, whereas a few CD34-positive fibroblastic cells were present in Antoni B areas. Neurofibromas and conventional MPNST exhibited a mixed proliferation of S-100 protein-, EMA/Glut1-, and CD34-positive cells, indicating a heterogeneous composition of the constituents. The catalyzed signal amplification (CSA) system demonstrated more numerous EMA-positive perineurial cells in neurofibromas than did the ENVISION+ method. Perineurial cell tumors (benign and malignant) were composed of EMA/Glut1-positive and S-100 protein-negative tumor cells. The present study confirmed the characteristic cellular composition to each nerve sheath tumor immunohistochemically and showed the usefulness of the nerve sheath cell markers. Glut1 as well as EMA are specific to perineurial cells, and CD34 seems to be immunoreactive to endoneurial fibroblasts.

Evaluation of the necessity for gastrectomy with lymph node dissection for patients with submucosal invasive gastric cancer

BACKGROUND

When cancer cells are found in the submucosal layer of an endoscopically resected specimen, patients are recommended to undergo gastrectomy with lymph node dissection. If it were possible to identify those patients in whom the risk of lymph node metastasis was negligible, it might be possible to avoid surgery.

METHODS

Among those who underwent gastrectomy for gastric cancer from 1980 to 1999, 1091 patients with a cancer invading the submucosa were studied. Clinicopathological factors (sex, age, tumour location, macroscopic type, size, ulceration, histological type, lymphatic-vascular involvement and degree of submucosal penetration) were investigated for their possible association with lymph node metastasis.

RESULTS

Lymph node metastases were found in 222 patients (20.3 per cent). Univariate analysis showed that larger tumour size (more than 30 mm), undifferentiated histological type, lymphatic-vascular involvement and massive submucosal penetration had a significant association with lymph node metastasis. Tumour size, histological type and lymphatic-vascular involvement were independent risk factors for lymph node metastasis. By combining these three factors with submucosal penetration of less than 500 microm, 117 patients could be selected as having a minimal risk of lymph node metastasis (95 per cent confidence interval 0-3.1 per cent).

CONCLUSION

Lymphadenectomy may not be necessary for patients with gastric cancer invading the submucosa who fulfil the above conditions

Mitochondrial tRNA(Ile) mutation in fatal cardiomyopathy

A patient with mitochondrial encephalomyopathy who died from progressive intractable cardiac failure at the age of 18 is reported. At the age of 4, he presented with short stature, but multiorgan disorders including deafness, focal glomerulosclerosis, epilepsy and dilated cardiomyopathy appeared later in his clinical course. Laboratory tests showed hyperlactatemia and hyperpyruvatemia. Histopathological findings demonstrated mitochondrial myopathy with ragged red fibers and focal cytochrome C oxidase-deficient fibers in skeletal and cardiac muscles. The activity of cytochrome C oxidase was 30% less than the control level in skeletal muscle. Sequencing of the entire mitochondrial tRNA genome revealed a novel point mutation in the tRNA(Ile) region (nt 4269). This A-to-G substitution was found in none of the 30 controls by screening using mispairing PCR and Ssp I digestion methods, suggesting that this new mutation was pathogenic in our case.

Pituitary and stalk lesions (infundibulo-hypophysitis) associated with immunoglobulin G4-related systemic disease: an emerging clinical entity

Inflammatory lesions of the pituitary gland are rarely encountered. Recently, the concept of immunoglobulin G4 (IgG4)-related systemic disease was proposed in Japan, and more than 20 cases have been reported as possibly associated with infundibulo-hypophysitis since 2000. We herein review such case reports in the published literature and in the abstracts of scientific meetings. Almost all cases involved middle-aged to elderly men presenting with various degrees of hypopituitarism and diabetes insipidus and demonstrating a thickened pituitary stalk and/or pituitary mass. These structures shrank remarkably in response to glucocorticoid therapy, even in a lower dose range similar to that prescribed as a replacement for adrenocortical insufficiency. Some of the anterior pituitary insufficiencies were also resolved by glucocorticoid administration. The presence of IgG4-related systemic disease and an elevated serum IgG4 level before glucocorticoid therapy were the main clues to a correct diagnosis of IgG4-related infundibulo-hypophysitis. Autoimmunity is suggested but not yet established to play a role in the pathogenesis for IgG4-related systemic disease. The fact that hypertrophic pachymeningitis and para-sinusitis accompanied some cases suggested that both sellar and parasellar structures are involved in the chronic inflammation. We therefore classify this disorder not as a variant form of primary autoimmune hypophysitis but as a secondary form of infundibulo-hypophysitis associated with IgG4-related systemic disease.