Vertical transport in GaAs/AlxGa1-xAs superlattices by a microwave time-of-flight technique.
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Biomedical subjects
Publications and source records attributed to J Jo.
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UNLABELLED: To evaluate the utility of CEA and CA 15.3 for early diagnosis of recurrence, serial serum determinations of both antigens were performed in 1023 patients (follow-up: 1-10 years, mean 6.2 years) with primary breast cancer (CA 15.3 in 533 cases) and no evidence of residual disease (NED) after radical treatment (radical mastectomy or simple mastectomy and radiotherapy). 246 patients developed metastases during follow-up. RESULTS: CEA and CA 15.3 were elevated ( > 10 ng/ml or > 60 U/ml, respectively) prior to diagnosis in 40% (98/246) and 41% (37/91) of the patients with recurrence, with a lead time of 4.9 +/- 2.2 and 4.2 +/- 2.3 months, respectively. When patients with locoregional recurrences were excluded, sensitivity improved to 46% (CEA) and 54% (CA 15.3), and to 64% with both tumor markers (CEA and/or CA 15.3). Higher levels of both CEA and CA 15.3 at diagnosis of recurrence, higher sensitivity in early diagnosis of relapse, and a higher lead time were found in ER+ (CEA) or PgR+ patients (CA 15.3) than in those that were negative for these receptors in the primary tumor (p < 0.001). Specificity of the tumor markers was 99% for both CEA (777 NED patients) and for CA 15.3 (444 NED patients), respectively. In conclusion, CEA and CA 15.3 are useful tools for early diagnosis of metastases, mainly in those patients with ER+ or PR+ tumors.
The presence of a tumor antigen in human colonic carcinomas and their metastases was described about 25 years ago. This antigen, called carcinoembryonic antigen (CEA), is one of the first known tumor markers. Since then, many more have been described, but CEA, determined alone or in combination with others, is still one of the most used. CEA is not organ specific and abnormal values may be found in a wide range of carcinomas, especially those with gastrointestinal involvement. CEA assay should not be used for cancer diagnosis because its sensitivity in patients without cancer metastases is low. In addition, abnormal CEA values may be found in patients with benign diseases. However, the probability of malignancy increases directly with CEA concentration. Its main clinical applications are prognosis, early diagnosis of recurrence and follow-up of patients with carcinomas. In a wide range of malignancies, CEA serum levels are clearly related to tumor stage. Presurgical CEA serum levels are a well-established prognostic factor in colorectal, breast and lung cancer. Patients presenting with increased preoperative CEA serum levels have both a shorter disease-free interval and lower survival than those with normal CEA levels. In the early diagnosis of recurrence, CEA also plays an important role: in about 70-85% of patients with colorectal tumors and in 40-50% with breast cancer, CEA serial increase is the first sign of tumor recurrence. In patients with disseminated tumors, serial determinations are also a useful tool for therapy monitoring: CEA values decrease with effective treatment while stable or increasing values are observed when treatment is not effective.
The diagnostic value of a new tumor marker, CYFRA 21-1, was studied in the sera of 50 controls, 206 patients with benign diseases and 469 patients with malignancies. Fifty controls showed mean serum concentrations of 1.2 +/- 0.5 ng/ml. Using 3.3 ng/ml as the cutoff, abnormal CYFRA levels were found in 13.1% of patients with benign diseases, mainly in those with liver cirrhosis (29.4%) or renal failure (20.8%), and in 44.4% (180/405) of patients with active cancer. Neither healthy subjects nor no evidence of disease (64 cases) patients had serum levels higher than this limit. CYFRA 21-1 results were significantly higher in patients with active cancer than in those with benign diseases or without active tumors (p < 0.0001). CYFRA serum levels were significantly higher in patients with metastases (59.5%) than in those with locoregional disease (33.7%; p < 0.001). CYFRA 21-1 sensitivity in patients with lung cancer was related to tumor histology with abnormal levels in 65.6% of patients with non-small cell lung cancer and in 25% of patients with small cell lung cancer (p < 0.0001). In breast cancer, CYFRA 21-1 concentrations were significantly higher in patients with metastases and in patients with primary tumors but with nodal involvement (p < 0.001).
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In a prospective study, CA 125 and CA 19.9 serum levels were measured in 229 patients with ovarian cancer [121 with active disease, 108 in complete remission (CR)], and in 20 patients with other malignancies. Abnormal levels of CA 125 were found in 90% of patients with active ovarian cancer, in 1.8% of those in CR and in 38% of cases with other malignancies. Abnormal CA 19.9 serum levels were found in 36, 9 and 48% of these groups, respectively. Serum levels of both tumor markers were related to tumor stage and histological type. The highest levels of CA 125 were found in serous adenocarcinoma and the lowest in the mucinous type (p < 0.0001). In contrast, significantly higher CA 19.9 values were found in mucinous carcinoma than in other histologies (p < 0.0001). CA 125 and CA 19.9 were useful for monitoring disease activity in 88.3 and 32%, respectively, while one or other tumor marker was useful in 92% of patients. At the time of the second-look operation, abnormal CA 125 serum levels were found in 32% (6/19) of patients with active disease and in none of those with CR (0/38). CA 125 sensitivity was 83% (5/6) in those patients with residual tumor > 2 cm and in 8% (1/13) in those with tumor < 2 cm. CA 19.9 values were abnormally high in 16% of cases with persistent disease and in 11% of CR patients. In conclusion, our results confirm that CA 125 is a useful marker in ovarian carcinoma. CA 19.9 improves the results obtained with CA 125 alone only in mucinous adenocarcinomas.
TAG-72 is a tumor-associated antigen identified by the monoclonal antibody B72.3. Serum levels of TAG-72 were measured in patients with non-malignant and malignant disease. TAG-72 is not a specific marker of cancer and slightly elevated levels of this antigen can also be detected in the serum of healthy subjects. However, our results show that specificity (92%) and positive predictive value (86%) of this marker are very high. TAG-72 levels above the cut-off limit of 6 U/mL were found in patients with tumors of various organs, including gastrointestinal, ovarian, lung and breast cancer. TAG-72 assay sensitivity is related to tumor stage with values being highest with advanced disease, especially in patients with gastric cancer and lung adenocarcinoma.
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Three alanine aminotransferases, two minor (AlaAT-1, AlaAT-3) and one major (AlaAT-2), were detected by native gel electrophoresis of leaf extracts from Panicum miliaceum L. AlaAT-2 was purified to homogeneity and a specific polyclonal antibody was raised against it which did not react with the other two forms of the enzyme. The enzyme, with an apparent molecular size of 102 kDa, appeared to be a dimer of a single 50-kDa polypeptide. The enzyme has a relatively broad pH optima with similar curves for the forward and reverse directions, ranging between 6.5 and 7.5. The Km values of this enzyme were 6.67, 0.15, 5.00, and 0.33 mM for alanine, 2-oxoglutarate, glutamate, and pyruvate, respectively. The activity of AlaAT-2 was found to increase markedly during leaf greening in parallel with the increase of immunochemically titrated protein, and it is suggested to function in the C4 photosynthetic cycle.
Pretreatment levels of phosphohexose isomerase (PHI) were above the cutoff limit of 107 IU/l in 41% of patients with benign intestinal diseases and in 46% of patients with colorectal cancer. Sensitivity of PHI was related to the presence of distant metastasis and the location of the primary tumor. Patients with rectal tumors presented a lower sensitivity than patients with colonic tumors. Pretreatment levels of PHI had prognostic value and patients with elevated levels of this enzyme showed a shorter disease-free interval in comparison with those patients with normal PHI activities. However, the prognostic significance of PHI was not independent of Dukes' classification. The present study indicates that PHI is not useful in the follow-up of patients with colorectal cancer after curative surgery because of its low sensitivity in the diagnosis of recurrences (47%) and its low specificity in patients without evidence of disease (76%).
Serum concentrations of cancer antigen 125 (CA 125) were determined for 373 patients with various liver diseases: 57 with acute hepatitis, 57 with chronic hepatitis, 244 with liver cirrhosis (86 compensated and 158 decompensated), and 15 with primary liver cancer. The antigen was measured simultaneously in the serum and ascitic fluid of 46 of the patients with liver cirrhosis and sequentially in the serum and ascitic fluid of another 25 cirrhotics treated with paracentesis and (or) diuretics. Abnormal results for CA 125 were detected in sera from 4% of the patients with acute or chronic hepatitis, 60% of the patients with liver cirrhosis, and 67% of the patients with primary liver cancer. The main factor associated with abnormal serum concentrations of this antigen was the presence of ascites, with pathological CA 125 values in 94% of patients with ascites without jaundice (mean 566 +/- 528 arb. units/mL), compared with only 40% of patients with jaundice and without ascites (mean 40.1 +/- 28.5 arb. units/mL) (P less than 0.001). High concentrations of CA 125 were mainly associated with spontaneous bacterial peritonitis. The serum concentration of CA 125 decreased after treatment with paracentesis, but increased in patients treated with diuretics rather than paracentesis. The release of this antigen in liver cirrhosis appears to be independent of the liver disorder and, rather, results from peritoneal synthesis of this antigen.
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Serum prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) levels were measured in 70 patients with benign prostatic hypertrophy (BPH) and in 70 patients with prostatic cancer. PSA was increased above the cutoff level of 10 ng/ml in 13% of patients with BPH and in 87% of patients with prostatic cancer. In contrast, abnormal PAP levels were found in 14 and 76% of patients, respectively. We concluded that, due to its high specificity, PSA is a useful marker in the management of patients with prostatic carcinoma and that it surpasses PAP in this regard.
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