Surgical significance of telomerase activity in noncancerous liver tissue from patients with hepatocellular carcinoma

Telomerase activity has been detected in tissue from noncancerous liver of patients with chronic liver disease, but its functional significance remains to be elucidated. We therefore evaluated the telomerase activity in surgically obtained noncancerous liver tissue from 20 hepatocellular carcinoma (HCC) patients. Two samples of noncancerous liver tissue were obtained from each patient: one from the parenchyma adjacent to the HCC nodules of the resected specimen; the other from the parenchyma distant from the HCC nodules of the remnant liver. Telomerase activity was assayed by a non-radioisotope quantitative system based on "TRAP-eze." Five samples from the noncancerous liver tissue adjacent to the HCC nodules (25.0%) were telomerase-positive; all such cases showed high-grade malignant potential, such as intrahepatic metastasis and/or portal vascular invasion and infiltration of the fibrous capsule in the corresponding HCC nodules, and telomerase positivity showed neither a relationship with the histological activity index scores nor a correlation with liver function. Interestingly, no telomerase activity was detected in any of the 20 samples obtained from the parenchyma of the remnant liver. These results indicate that telomerase in noncancerous liver tissue is associated not with the hepatic condition accompanying HCC, but with the biological characteristics of the tumor itself, and may derive from infiltrating cancer cells. Determination of telomerase status may aid in designing more effective surgical procedures.     

Clinical implications of telomerase activity levels in acute leukemia

In the present study, we used the telomeric repeat amplification protocol assay, an internal telomerase assay standard, and an automatic DNA sequencer to detect and quantitate telomerase activity in blood samples obtained from normal and acute leukemia patients. Telomerase activity was analyzed in 78 acute leukemia patients and ranged from 0.65 to 147 relative to the internal standard. Compared to the age-matched normal levels of telomerase activity in the peripheral blood cells, we determined that 45 (81.8%) of 55 acute myeloid leukemia (AML) and 16 (69.6%) of 23 acute lymphoid leukemia patients had elevated telomerase activity. There was no relationship between peak telomere length and telomerase activity in both acute lymphoid leukemia and AML patients. In AML, the level of telomerase activity was associated with French-American-British subtypes and cytogenetics, and patients with elevated telomerase activity had high leukocyte counts and more frequent extramedullary involvement during the disease. Among 78 patients, 5 had high levels of telomerase activities similar to immortalized leukemia cell lines; these 5 patients had a very poor prognosis (P < 0.05). The levels of telomerase activity significantly decreased in patients in complete remission. Most of the patients in complete remission showed a normal level of telomerase activity; however, two of them had low to moderate telomerase activity, and they relapsed shortly after entering complete remission. In relapsed patients, there is a general trend for increased telomerase levels, and 2 of the 13 patients retained high telomerase activity, whereas the other 11 had normal to moderate telomerase activity. These results suggest that telomerase activity may be a useful additional method for monitoring the disease condition in acute leukemia patients.     

Diagnostic significance of telomerase activity and telomere length in endoscopic sample of colorectal cancer

Telomeres are located on both ends of individual chromosomes in eukaryotes. It has been reported that telomerase activity and telomere reduction can be detected in most human cancers. We examined telomerase activity and telomere length in colorectal cancer tissues obtained by colonoscopy. Telomerase activity was examined by the TRAP (telomeric repeat amplification protocol) assay and was detected in 21 of 26 (81%) primary colorectal carcinoma tissues. Two of 9 (22%) colorectal polyp were telomerase positive. Telomere length was analyzed by Southern blotting and there was reduction in telomere lengths in 12 of 15 (80%) primary colorectal carcinoma and 3 of 6 colorectal polyp, compared to the corresponding normal colonic mucosa. Therefore, telomerase activity and telomere length may serve as an useful tool for preoperative cancer diagnosis.     

Lack of telomerase in desmoids occurring sporadically and in association with familial adenomatous polyposis

BACKGROUND: Telomerase activity may be required for unlimited growth of cells and is repressed in most somatic tissues, but is detectable in immortal cell lines, germ cells, many malignancies and some benign lesions. Desmoids are proliferative, locally invasive, non-metastasizing fibromatous tumours which rarely regress. They occur frequently in familial adenomatous polyposis (FAP), causing significant morbidity and death. Telomerase activity was assayed in desmoids from patients with and without FAP to assess the role of telomerase in the development of these lesions, and its potential as a prognostic marker and possible target for treatment. METHODS: Protein extracts from 11 desmoids from nine patients with FAP, and ten desmoids from ten patients without FAP, were analysed for telomerase activity by the telomeric repeat amplification protocol, a sensitive polymerase chain reaction-based assay. Six fibrosarcomas and a fibrosarcoma cell line were used as positive controls; all displayed telomerase activity. RESULTS: No telomerase activity was detected in any of the 21 desmoids studied. CONCLUSION: These results indicate that desmoid tumours are one of the intriguing exceptions to the emerging view that re-expression of telomerase activity accompanies the development of preneoplastic and neoplastic tissues, and suggest that alternative mechanisms may operate in these proliferative neoplasms.     

Cirrhosis of the liver as a precancerous condition

Cirrhosis of the liver can be regarded as premalignant state, since more than 80 percent of hepatocellular carcinoma (HCC) in the western world develop in a cirrhotic liver. The risk to develop this malignancy depends on the activity of the underlying cirrhosis, its etiology and the duration of the disease. Patients suffering from cirrhosis of the liver due to HBV-, HCV- or HDV-infection and patients with genetic hemochromatosis exhibit a high risk for HCC. This risk is further increased by cocarcinogens, such as alcohol, nicotine and toxins. Ultrasound and AFP-studies aim to diagnose HCC early. The sensitivity of AFP in the serum is remarkably low (about 64%). In contrast a normal AFP-concentration (< 20 ng/ml) carries a high negative prognostic value (> 90%). Patients suspected to suffer from HCC according to the results of screening procedures should be subjected to additional radiologic investigations, such as CT-arterioportography or lipiodol-angiography.     

The prognosis of resected lung carcinoma associated with atypical adenomatous hyperplasia: a comparison of the prognosis of well-differentiated adenocarcinoma associated with atypical adenomatous hyperplasia and intrapulmonary metastasis

The overall objective of this study was to determine whether peroral treatment with the 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitor fluvastatin influences the leukocyte-endothelial cell adhesion (LECA) observed in postcapillary venules of hypercholesterolemic rats. Rats were fed either normal chow or a chow supplemented with 1% cholesterol for 10 days. Leukocyte adherence and extravasation, leukocyte rolling velocity, red blood cell velocity, and vessel diameter were monitored in mesenteric venules superfused with either 100 nmol/L platelet-activating factor (PAF) or 20 nmol/L leukotriene B4 (LTB4). Hypercholesterolemic rats exhibited an exaggerated LECA response compared with their normocholesterolemic counterparts. In hypercholesterolemic rats, treatment with fluvastatin significantly attenuated the leukocyte-adherence responses to PAF and LTB4 as well as the leukocyte emigration response to LTB4. Fluvastatin treatment also inhibited the PAF- and LTB4-induced reductions in leukocyte rolling velocity. These findings indicate that fluvastatin blunts the inflammatory responses elicited in post-capillary venules by lipid mediators.     

Comparison of the proliferative capacity of adenomatous hyperplasia and well differentiated hepatocellular carcinoma

The identification of nodular lesions, which used to be difficult to differentiate from well differentiated hepatocellular carcinomas, has become frequent since the advent of ultrasonic-guided liver tumor biopsy techniques. This is because adenomatous hyperplasias, which are regarded as putative precancerous lesions, which needed to be differentiated from malignant lesions, often an a nodular. The histological specimens of 52 tumors, obtained from patients with chronic liver injury, were subjected to immunohistological staining for proliferative cell nuclear antigen (PCNA). Findings obtained by this immunohistological technique were compared with those obtained by histological image analysis. Adenomatous hyperplasias with fatty changes or with a high nuclear cytoplasmic ratio on image analysis were frequently PCNA-positive (P < 0.01). These nodular lesions, whose morphological characteristics were similar to those of well differentiated hepatocellular carcinomas, showed a high potential for growth. It seems that PCNA may be a useful indicator for increasing our understanding of the progress from adenomatous hyperplasia to hepatocellular carcinoma.     

Clinical usefulness of helical scanning CT (HES-CT) for orbital lesion

As part of an investigation of the structural requirements for the induction, by phenobarbital-type inducers, of a coordinate pleiotropic response consisting of increases in hepatic cytochrome P450 2B (P450 2B) activity, increases in other phase I and II enzyme activities, and liver hypertrophy, we have examined a series of analogues of phenobarbital in which the ethyl/phenyl substitution at the sp3 carbon of the parent molecule was kept constant while the heterocyclic portion of the molecule was modified. The induction of hepatic P450 2B protein and ethoxy-, pentoxy-, and (benzyloxy)resorufin O-dealkylation activities, and epoxide hydration activity and liver/body weight ratio increase were examined in male F344/NCr rats fed the various congeners for 14 days at doses equimolar to 500 ppm phenobarbital. Increases in the measured parameters were maximal in rats fed phenobarbital or 5-ethyl-5-phenylhydantoin. The responses to primidone or 2-ethyl-2-phenylsuccinimide were approximately 65% of maximal, while glutethimide yielded a response approximately 50% of maximal. Induction of this response in rats fed the ring-opened and decarboxylated analogues, (ethylphenylacetyl)urea and 2-ethyl-2-phenylmalonamide, were < 25% of maximal. 5-Ethyl-5-phenyloxazolidinedione caused minimal increases in the measured end points when administered at a dose equimolar to 500 ppm phenobarbital. The profound differences among the congeners in ability to induce P450 2B protein and associated catalytic activities were not due to differences in food consumption by the various groups of rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Focal nodular hyperplasia of the liver

The management of focal nodular hyperplasia (FNH) of the liver requires a systematic approach. After a histologic diagnosis of FNH is obtained, asymptomatic lesions can be observed safely with regular follow-up and treated if they become symptomatic or enlargement occurs. In the case presented here, we have elected follow-up with serial CT scans because our patient is asymptomatic and the lesion has not significantly enlarged. Patients who have symptomatic lesions while taking an oral contraceptive can have conservative follow-up when they stop taking the oral contraceptive, because regression of FNH has been reported to occur after cessation of oral contraceptive use. If the patient remains symptomatic or if the lesion enlarges after discontinuance of oral contraceptive use, surgical resection is warranted. Other symptomatic patients, including those with a previous history of taking oral contraceptives, should be treated by surgical resection or, when resection is not possible, by embolization or ligation of the hepatic artery, because symptomatic patients are at risk for having malignant lesions misdiagnosed as FNH.     

A case of double primary adenocarcinoma of the lung with multiple atypical adenomatous hyperplasia

A case of double primary adenocarcinoma of the lung with multiple atypical adenomatous hyperplasia (AAH) in a 77-year-old woman is reported. Histopathologically, in the resected left upper lobe of the lung, both cancers were diagnosed as well-differentiated papillary adenocarcinoma, and 161 lesions of AAH were also found. Both the cancer lesions and six AAH (greater than 3 mm in diameter) were examined with regard to immunoreactivity of carcinoembryonic antigen (CEA) and p53 gene product, microsatellite instability (MI) and loss of heterozygosity (LOH) on chromosome 9q and 17q by polymerase chain reaction (PCR). Although both cancers expressed CEA, they did not show clonal immunoreactivity for the p53 gene product. Atypical adenomatous hyperplasia expressed CEA weakly and showed no immunoreactivity for p53 gene protein. Both carcinomas showed LOH on chromosome 17q, and one of them showed LOH on chromosome 9q. In six AAH, LOH on chromosome 17q was detected in two tumors, and one of them also showed LOH on chromosome 9q. One AAH, which was negative for LOH on chromosome 17q and 9q, showed MI at D17S791. These results indicated that AAH is a clonal neoplastic lesion with genetic abnormalities and should be called intraepithelial pneumocyte neoplasia, and that each of the numerous papillary lesions in this case was considered to be an independent lesion.     

Detection of telomerase activity in oral lesions

We present a rare complication of pericardiectomy and the effective management thereof. A 67-year-old female with dyspnea and upper abdominal pain was received at our department upon referral. Chest roentgenogram and cardiac catheterization preceded a diagnosis of constrictive pericarditis. Pericardiectomy was performed subordinate to median sternotomy and left anterolateral thoracotomy. Extubation was carried out on day 2 but reintubation was necessitated on the same day as a result of progressive dyspnea. Chest roentgenogram revealed an atelectasis of the left lung. Fiberoptic bronchoscopy showed left main bronchial stenosis resulting from a pulsating external structure. A postoperative computed tomogram substantiated the stenotic left main bronchus between the dilated left pulmonary artery and the thoracic descending aorta. An expandable metallic stent for the treatment of this complication was selected over other invasive procedures. Two years of follow-up reveal no complications. Accordingly, an expandable metallic stent has demonstrated its effectiveness not only on bronchial stenosis due to malignancy or tuberculosis but on benign cases such as this as well.     

Expression of telomerase activity in human chorion

Telomerase activation is required for cellular immortalization and is found in most malignant tumors. Normal somatic cells are generally telomerase-negative, except for stem cells in renewing tissues. During pregnancy, human trophoblast continues to proliferate and acts as proliferating stem cells for the development of chorion and the formation of placenta. In the present study, a total of 105 chorions from placentas at various weeks of gestation were examined for telomerase activity using the telomeric repeat amplification protocol (TRAP) assay. Twenty-five of 33 (76%) normal early chorions at 5 to 9 weeks gestation were telomerase-positive. Chorions from early spontaneous abortions also exhibited telomerase activity but at a low level. In contrast, only 2 (4%) late chorions at 34 to 41 weeks gestation expressed telomerase activity. Significant telomerase activity was observed in trophoblast cell fractions of chorion, demonstrating trophoblast to be the source of the activity. Expression of human telomerase catalytic subunit (hTRT) was observed in early chorions, but not in late placenta, and there was a close correlation between telomerase activity and hTRT expression. In contrast, expression of human telomerase RNA component (hTR) was observed in both early and late chorions and was not liked to telomerase activity. These findings suggest that telomerase activity in chorion is critically regulated over the course of gestation, associated with hTRT expression. The findings of the present study also appear to support the emerging concept that normal somatic cells with stem cell-like characteristics can express telomerase activity.     

Clinical and diagnostic significance of microalbuminuria and activity of tubular enzyme N-acetyl-beta-D-glucosaminidase (NAG) determination in patients with hyperuricosuria

AIM: Development of the approaches to detection of hyperuricosuric stage of purin metabolism derangement and specification of methods for early diagnosis of urate damage to the kidney. MATERIALS AND METHODS: The study included 115 young subjects whose parents suffer from gout with renal involvement or isolated urate nephropathy. Each patient was examined clinically with evaluation of family history for gout risk factors. Three times for 9 months measurements were made of uricemia and uricosuria, microalbuminuria and activity of tubular enzyme NAG. RESULTS: 45 (39.1%) patients had neither disturbances of purin metabolism nor renal affection. 70 (60.9%) patients had hyperuricosuria. In 23 (32.9%) of them microalbuminuria increased to > 20 mg/day, NAG activity to 5 u/l. Chronic tubulointerstitial nephritis was diagnosed in 17 (73.9%) patients. Six patients (26.1%) developed asymptomatic affection of the kidneys. The rest 47 patients had normal levels of microalbuminuria and NAG. There were 3 cases of hyperuricemia with microalbuminuria rising to 160-200 mg/day and further development of urinary syndrome. Hyperuricemia in them was registered at microalbuminuria higher that 160 mg/day. CONCLUSION: Microalbuminuria higher than 20 mg/day and NAG activity higher than 5 u/day are important diagnostic indicators of renal affection in hyperuricosuria including asymptomatic one. Microalbuminuria above 160 mg/day gives grounds to discuss the role of morphological changes prior to proteinuria.     

On the significance of temporally structured activity in the dorsal lateral geniculate nucleus (LGN)

Higher organisms perceive information about external or internal physical or chemical stimuli with specialized sensors that encode characteristics of that stimulus by a train of action potentials. Usually, the location and modality of the stimulus is represented by the location and specificity of the receptor and the intensity of the stimulus and its temporal modulation is thought to be encoded by the instantaneous firing rate. Recent studies have shown that, primarily in cortical structures, special features of a stimulus also are represented in the temporal pattern of spike activity. Typical attributes of this time structure are oscillatory patterns of activity and synchronous discharges in spatially distributed neurons that respond to inputs evoked by a coherent object. The origin and functional significance of this kind of activity is less clear. Cortical, subcortical and even very peripheral sources seem to be involved. Most of the relevant studies were devoted to the mammalian visual system and cortical findings on temporally structured activity were reviewed recently (Eckhorn, 1994, Progr. Brain Res., Vol. 102, pp. 405-426; Singer and Gray, 1995, Annu. Rev. Neurosci., Vol. 18, pp. 555-586). Therefore, this article is designed to give an overview, especially of those studies concerned with the temporal structure of visual activity in subcortical centers of the primary visual pathway, which are the retina and the dorsal lateral geniculate nucleus (LGN). We discuss the mechanisms that possibly contribute to the generation and modulation of the subcortical activity time structure and we try to relate to each other the subcortical and cortical patterns of sensory activity.