Biomedical subjects
Publications and source records attributed to V G Lemekhov.
An evaluation is presented of the data on use of video-assisted thoracoscopy in the diagnosis and therapy of 45 patients with single circular formations in the lung. Indications and contraindications for the management of benign and malignant single tumors of the lung are discussed alongside a review of the Russian and foreign literature.
The genetic polymorphism of metabolizers of tobacco smoke carcinogens can influence individual susceptibility to lung cancer. The study was concerned with the Mspl-polymorphism of the CYP1A1 gene responsible for encoding aryl hydrocarbon hydroxylase. It also plays a role in the activation of polycyclic aromatic hydrocarbons (PAH). The CYP1A1 alleles and genotype distribution in 146 lung cancer patients was compared with that in 230 healthy donors. Another control group consisted of 259 "cancer-resistant" subjects, i.e. tumor-free smokers and non-smokers aged 75 and more. The CYP1A1 allele incidence (19%) in patients with squamous lung cancer was significantly higher than in the control cohorts (11%) which is consistent with the leading role of PAH in the etiology of this pathology.
Video-assisted thoracoscopy for differential and improved diagnosis was successful in 245 out of 249 patients (98.3%) with various chest neoplasms. Video-assisted surgical procedures were performed in 50 (20%). Complications were reported in 4 (1.6%). The method proved highly-effective as well as fairly safe and sparing.
The published studies of onco-associated genetic polymorphisms are characterized by insufficient interlaboratory reproducibility. The inconsistency of the results can be partially attributed to some characteristics of patients and control groups, which are used for the comparison of allele frequencies. For instance, many investigations involve so-called "healthy donors" as a standard. However, the efficiency of such a comparison can be questioned; indeed, as an individual life-time risk of malignancy reaches as high as 40-50%, a significant part of "healthy donors" would soon or later become the oncological patients. Here we tested the advantage of using "true" oncologically tolerant individuals as an additional control, e.g. tumor-free people, who succeeded to achieve an elderly age without signs of any neoplastic disease. GSTM1 gene polymorphism was used as a "positive control" for this novel design of molecular epidemiological study, as the GSTM1-null genotype displays slight but reproducible association with lung cancer risk. In the present investigation, GSTM1-deficiency was detected in 45% elderly tumor-free individuals, 55% healthy middle-aged donors, and 59% lung cancer patients. The minimal frequency (43%) of GSTM1(-) genotype was detected in elderly tumor-free smokers, and the maximal one (100%) was found in never-smoking lung cancer patients. Thus, the comparison of lung cancer patients to the "true" oncologically tolerant cohort (elderly tumor-free individuals, especially smokers) revealed more demonstrative deviations for the unfavorable genotype, than the traditional comparative analysis between oncological patients and healthy donors.
Diagnostic potential of video-assisted thoracoscopy was evaluated in 66 patients (36 males and 30 females) with neoplasms (aged 24-68 yrs). When used in conjunction with biopsy, it confirmed the following diagnoses: lymph proliferative disease (23), mediastinal malignancies (11), sarcoidosis (21), benign mediastinal tumors (7), Castleman's benign lymphoma (2) and mediastinal cyst (2). Clinical diagnosis was substantially changed in 40 (61%) cases as a result of videothoracoscopy application. It has proved precise, fairly safe and conservative; it has a potential in diagnosis of mediastinal tumors.
A 45-year experience of diagnosis and treatment of lung cancer is presented. In groups at high risk of cancer, photoroentgenographic screening has proved effective. The use of out-patient complex pulmonologic examination serves to improve identification of central cancer. Early cancers of the lung can be reliably detected in 92.2% of patients with central cancer and in 92.6%-peripheral localizations of tumor. After radical surgery, 5-year survival in cases of stage I tumor was 63.5: stage II-43.5 and stage III-22.9%, mean 5-year survival (irrespective of stage) being 37%. Postoperative radiation was shown to be followed survival over 5 years in cases of non-small cell carcinoma (N2). Early diagnosis and combined therapy are key in raising efficacy of lung cancer treatment.
The levels of 3 DNA repair enzymes involved in alkylation and oxidative DNA damage repair in human peripheral blood leukocytes were measured in 20 smokers and 17 non-smokers. No differences in O6-alkylguanine-DNA-alkyltransferase (AGT) activity were found between the 2 groups and the AGT distribution within the population appeared to be unimodal. In contrast, the mean activities of both the methylpurine (MeP)- and the 2-6-diamino-4-hydroxy-5N formamidopyrimidine (FaPy)-DNA glycosylases were higher in the smokers, although only the difference between the MeP-DNA glycosylase means was statistically significant. The standard deviations of these 2 enzymes were also higher in the smokers. The MeP-DNA glycosylase activity showed a bimodal distribution when all subjects were considered. This may in part be due to the smoking habit; 83% of the subjects with enzyme activities higher than 500 fmoles/mg protein were current smokers, whilst 85% of the non-smokers had lower enzyme activities. However, if the smokers were considered separately, a bimodal distribution of this enzyme activity could still be observed. No strong correlation was observed between enzyme activity and age, although the slopes of the regression lines of enzyme activity on age were all negative. The relationship between enzyme activities was studied by bivariate distribution and a strong correlation was only found between the MeP-DNA glycosylase and the FaPy-glycosylase, with the highest values of both enzyme activities being observed in the smokers and the lowest in the non-smokers. Our results suggest that the activity of certain DNA repair enzymes can be modulated by environmental exposure.
A clinico-roentgenologic study of 67 patients with hamartoma of the lung was carried out. Hamartoma could not be even suggested unless X-ray examination was performed but even this procedure sometimes failed to identify the disease. It was far from being each case that typical roentgenologic features of hamartoma were observed. Transthoracic needle biopsy may be helpful in identifying the nature of a roentgenologically detected tumor. Roentgenologically, hamartoma should be first of all distinguished from peripheral lung cancer. When clinico-roentgenologic and needle biopsy data are inconclusive with respect to lung cancer diagnostic thoracotomy should be performed.
Diagnosis was improved and the duration of examination and costs reduced as a result of bronchoscopy carried out in outpatients. Lung cancer was frequent in males over 45 years with a long history of heavy smoking. In such cases, the disease presented as long-lasting acute pneumonia. The high diagnostic value of the procedure and freedom from complications suggest that it be more closely integrated with outpatient treatment practice.
A long-term experience with oncopulmonary examinations points to their efficacy in detecting lung cancer, early forms included. As a result, the number of primary patients operated on for lung cancer or undergoing lung resection has grown in Leningrad for the past 17 years from 15.6 to 22% and from 13.2 to 19%, respectively. The best diagnostic results for central cancer have been obtained in application of bronchoscopy and with transcutaneous needle biopsy--for peripheral cancer. (The rate of morphological verification of cancer was over 96% for either procedure). The following patterns of early forms of central cancer of the lung have been identified: Ca in situ, microinvasive cancer, incipient invasive cancer and advanced invasive cancer.
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The study was concerned with an evaluation of the results of examination of 203 breast and 158 lung cancer patients. Such constitutional features as excessive body weight, body fat level and body surface area as well as adipocyte diameter and FFA profile in subcutaneous fat tissue were to be in a greater correlation with lipid (triglyceride, cholesterol and non-esterified FFA) levels than the rates of lipolysis and liposynthesis in both study groups. There may be minor differences in the mechanisms of hypertriglyceridemia development in breast and lung cancer patients. The rise in blood triglyceride level was largely due to basal hyperinsulinemia and glucocorticoid hyperproduction in lung cancer patients, whereas, in breast cancer patients it was mostly determined by resistance to insulin and an increase in body surface area contributed by lean body mass.
Subcutaneous adipose tissue was examined in 77 patients with breast cancer, 61 patients with lung cancer and in a control group of 23 male and 27 female with non-tumor pathology; the weight and age of controls matched those of cancer patients. The obesity in breast cancer patients was of the hypertrophic type, and of combined type (hypertrophic-hyperplastic) in patients who were more than 50% overweight. The increased level of adipose tissue in lung cancer patients was mostly due to the larger size of adipocytes. The concentration of unsaturated fatty acids in adipose tissue in breast cancer patients was in direct correlation with the level of this tissue and adipocyte size, while, in lung cancer group, this correlation was reversed. There was no inverse correlation between the size and c-AMP level of adipocytes in both cancer groups. Resistance to the inhibitory effect of glucose on lipolysis occurring in adipose tissue was more frequent in cancer patients than in controls. Antilipolytic effect of insulin in subcutaneous adipose tissue of breast cancer patients was less pronounced than in lung cancer group. Liposynthetic activity in adipose tissue was identical in all study groups. Lipolytic activity in adipose tissue was enhanced in both cancer groups, but in the breast cancer group it was in direct correlation with overweight, while in lung cancer patients--with the degree of tumor progression.
Surgical procedures such as mediastinoscopy (101 cases) and parasternal mediastinotomy (6 cases) were used for improvement of diagnosis of lesions in mediastinal organs. As a result of complex examination including histological methods, malignant lymphoma was diagnosed in 12 cases, Boeck's sarcoidosis--75, mediastinal form of lung cancer--8, tuberculosis of mediastinal lymph nodes--6 and other lesions of organs of the mediastinum--in 6 cases.
A comparative assessment was made between different kinds of anesthesia used with diagnostic purposes in fibroscopy such as anesthesia with fluothane--nitrous oxide, anesthesia with trilene, the sombrevin--seduxen intravenous anesthesia and local anesthesia. Observations were performed in 127 patients. The authors consider local anesthesia to be the method of choice in diagnostic fibrobronchoscopy. In cases when the local anesthesia can not be used it is expedient to employ the intravenous sombrevin--seduxen anesthesia.
Transthoracic needle biopsy was performed in 134 patients with peripheral coin lesions of the lung. The mentioned technic is very valuable diagnostically and enables the precise diagnosis to be established in the vast majority of patients with coin lesions of the lung in the shortest time possible. Transthoracic needle biopsy, when performed properly, is not a hazardous procedure, that makes it possible to recommend this technic for diagnosing peripheral coin lesions of the lung.
The authors give a comparative estimation of the results of 217 mediastinoscopies, 58 parasternal mediastinotomies, performed in 274 patients with pulmonary cancer to determine precisely their operability. Positive findings in mediastinoscopy were noted in 66 (33.4%) of 217 patients, especially in cancer of median localization (in 42 of 153 patients or in 32%) and of the right lung predominantly (in 51 of 134 patients or in 45.5%). Parasternal mediastinoscopy yielded positive findings in 30 (51.7%) of 58 patients. This method proved to be mostly reliable in examining patients with peripheral bronchus cancer, especially in left lung localization of the tumor. The results of mediastinoscopy and parasternal mediastinotomy are similarly conditioned by the morphological structure of the tumor. Due to mediastinoscopy and parasternal mediastinotomy 57 (26.6%) of 222 patients, previously referred to as being "operable," proved to be inoperable. These methods also would aid in avoiding tentative thoracotomy or nonradical surgery in 78 (30.7%) of 254 patients, primarily considered to be "operable" or "doubtfully operable".