Neuroimmunoregulation and cancer (review)

It is certain that neuroimmune mechanisms play a role in host defence against cancer. However, this interaction is highly complex and many variations are possible according to the nature of the neoplasms involved. There are indications that adaptive immunity is present in a significant proportion of tumor bearing hosts, and this defence may be boosted by specially designed vaccines and cytokines. Natural immune mediators are also implicated in resistance against tumor development. Here we review the evidence suggesting that hormonal manipulation of the host can result in the elevation of immune defences against cancer. Such manipulation strengthens both the adaptive and natural immune defences of the host, both of which play significant roles. Natural defence mechanisms are boosted by cytokines and hormones during febrile reactions which are now known as the acute phase response. It is suggested that hormonal stimulation of immune mechanisms coupled with the usual immunostimulants already in use may be employed to good advantage for the combination immunotherapy of cancer. Modern molecular biology approaches permit the development of laboratory monitoring procedures which may be used for the prediction and follow-up of therapeutic success.     

Vitamin B6 and cancer (review)

Vitamin B6 is required for normal growth and development, in general. The effect(s) of the vitamin on tumor growth, particularly of Morris hepatomas, and on metabolic function (i.e. enzyme activity) are herewith reviewed. Evidence is presented on the biochemical relationship(s) of pyridoxal 5'-phosphate with thymidylate synthetase and its inactivation by fluorodeoxyuridylate as well as of the therapeutic effects of direct treatment in situ with the antivitamin complexing agent L-penicillamine.     

Effect of dietary fats on the incidence of 7,12-dimethylbenz(a)-anthracene-induced tumors in rats

Female rats have been fed high fat diets containing either polyunsaturated or saturated fat. After being fed either of the diets for 4 weeks, some of the animals received an intragastric dose of 7,12-dimethylbenz(a)anthracene (DMBA). At this point, the diets of half of the animals were interchanged so that animals previously fed the polyunsaturated fat diet were fed the saturated fat diet and vice versa. The cumulative incidence of tumor-bearing rats among DMBA-dosed rats was greater when the polyunsaturated fat diet was fed. The mean induction time of tumors decreased and the proportion of tumor-bearing rats which developed malignant tumors increased when the polyunsaturated fat diet was fed. This promotional effect of the polyunsaturated fat diet was exerted only when the diet was fed after DMBA administration.     

Current state of development of new ceramic materials (review of foreign literature)

The current state of development of advanced ceramic materials abroad is reviewed. The volume of production of powders and parts from advanced ceramics in the world, North America, Japan, and Western Europe for 1989–1995, and the structure of their application are shown. Prospects for advanced ceramics development up to the year 2000 are discussed. Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1–2(405), pp. 101–113, January–February, 1999.     

Manganese superoxide dismutase (MnSOD) genetic polymorphisms, dietary antioxidants, and risk of breast cancer

Oxidative stress, resulting from the imbalance between prooxidant and antioxidant states, damages DNA, proteins, cell membranes, and mitochondria and seems to play a role in human breast carcinogenesis. Dietary sources of antioxidants (chemical) and endogenous antioxidants (enzymatic), including the polymorphic manganese superoxide dismutase (MnSOD), can act to reduce the load of oxidative stress. We hypothesized that the valine-to-alanine substitution that seems to alter transport of the enzyme into the mitochondrion, changing its efficacy in fighting oxidative stress, was associated with breast cancer risk and that a diet rich in sources of antioxidants could ameliorate the effects on risk. Data were collected in a case-control study of diet and breast cancer in western New York from 1986 to 1991. Caucasian women with incident, primary, histologically confirmed breast cancer were frequency-matched on age and county of residence to community controls. Blood specimens were collected and processed from a subset of participants in the study (266 cases and 295 controls). Using a RFLP that distinguishes a valine (V) to alanine (A) change in the -9 position in the signal sequence of the protein for MnSOD, we characterized MnSOD genotypes in relation to breast cancer risk. We also evaluated the effect of the polymorphism on risk among low and high consumers of fruits and vegetables. Premenopausal women who were homozygous for the A allele had a 4-fold increase in breast cancer risk in comparison to those with 1 or 2 V alleles (odds ratio, 4.3; 95% confidence interval, 1.7-10.8). Risk was most pronounced among women below the median consumption of fruits and vegetables and of dietary ascorbic acid and alpha-tocopherol, with little increased risk for those with diets rich in these foods. Relationships were weaker among postmenopausal women, although the MnSOD AA genotype was associated with an almost 2-fold increase in risk (odds ratio, 1.8; confidence interval, 0.9-3.6). No appreciable modification of risk by diet was detected for these older women. These data support the hypothesis that MnSOD and oxidative stress play a significant role in breast cancer risk, particularly in premenopausal women. The finding that risk was greatest among women who consumed lower amounts of dietary antioxidants and was minimal among high consumers indicates that a diet rich in sources of antioxidants may minimize the deleterious effects of the MnSOD polymorphism, thereby supporting public health recommendations for the consumption of diets rich in fruits and vegetables as a preventive measure against cancer.     

Effect of amifostine (Ethyol) on the development of extraembryonic blood vessels in chick embryos

An unrecognised right aortic arch (RAA) found at thoracotomy may complicate the repair of oesophageal atresia (OA) and tracheo-oesophageal fistula (TOF). This paper analyses the patient characteristics, peri-operative management, and outcome of 16 infants with a RAA, and proposes management guidelines. Between 1948 and 1996, 709 patients with OA/TOF were admitted to the Royal Children's Hospital, of whom 13 had a RAA. Three additional cases from two other paediatric surgical units were included. All 16 case records were reviewed retrospectively. The overall incidence of RAA in OA was 1.8%. Neither a chest radiograph in 16, nor antenatal ultrasonography in 7 detected a RAA. Post-natal echocardiography (ECHG) detected a RAA in only 1 of 7 infants examined; that patient underwent repair of the OA through a left (L) thoracotomy. The other 15 infants underwent initial right (R) thoracotomy. Six of these had a complete repair from the R side and 5 had division of the fistula only; 2 of these 5 had initial division of the fistula, and the OA was repaired through a repeat R thoracotomy 4 and 7 weeks later. In the remaining 4 infants where the fistula could not be located at the initial R thoracotomy, complete repair proved possible through the L chest. Three of these infants underwent an immediate L thoracotomy; the 4th had a delayed L thoracotomy 1 week later. There were 6 deaths: these occurred early in the study and were related to severe prematurity, congenital heart disease (CHD), and post-operative respiratory complications. CHD was identified in 11 of 16 infants (71%). Routine pre-operative ECHG is unreliable in determining the laterality of the aortic arch. Should a RAA be encountered during a R thoracotomy for OA, it is often possible to divide the fistula and repair the OA from that side, but where repair looks potentially difficult it is wise to proceed to an immediate L thoracotomy.     

Effect of Helicobacter pylori eradication on subsequent development of cancer after endoscopic resection of early gastric cancer

Although epidemiological studies strongly suggest an association between gastric cancer and Helicobacter pylori infection, there has been no clinical report indicating that cure of the infection prevents cancer. We conducted a nonrandomized H. pylori eradication trial in patients whose gastric cancer was removed by endoscopic resection (ER). We investigated the effect of treatment on the histopathology of the gastric mucosa, as well as on the incidence of metachronous gastric cancer during the long-term clinical and endoscopic follow-up. One hundred and thirty-two patients with early gastric cancer underwent ER and had H. pylori infection. Sixty-five (group A) were treated with omeprazole and antibiotics to eradicate the infection, and 67 (group B) were not. All patients were followed for 2 years post ER. After eradication treatment in group A, the disappearance of neutrophil infiltration in the antrum and body of the stomach was observed as was a decrease of the severity of intestinal metaplasia. Endoscopy after ER detected no new gastric cancers in these patients. After 3 years of follow-up, 6 (9%) of the 67 patients in group B had a new early-stage, intestinal-type gastric cancer endoscopically diagnosed. The above results suggest that H. pylori eradication may improve neutrophil infiltration and intestinal metaplasia in the gastric mucosa and inhibit the development of new carcinomas. This finding should be confirmed in a randomized, controlled trial.     

A review on family history of breast cancer: screening and counseling proposals for women with familial (non-hereditary) breast cancer

In a neural model of olfactory bulb processing, we demonstrate the putative role of the modulation of two types of inhibition, inspired by electrophysiological data on the effect of acetylcholine and noradrenaline on olfactory bulb synaptic transmission. Feedback regulation of modulation based on bulbar activity serves to 'normalize' the activity of output neurons in response to different levels of input activities. This mechanism also decreases the overlap between pairs of output patterns (Mitral cell activities), enhancing the discrimination between overlapping olfactory input patterns. The effect of the modulation at the two levels of interneurons is complementary: while an increase in periglomerular inhibition decreases the number of responding output neurons, a decrease in granule cell inhibition increases the firing frequencies of these neurons.     

Tumor-reactive immunoglobulins in ovarian cancer: diagnostic and therapeutic significance? (review)

Inhibition of the immune system has been observed in association with most stages of ovarian cancer; however, the mechanisms involved in the induction and maintenance of this chronic immune unresponsiveness associated with cancer progression are poorly understood. This immunosuppressed state is primarily defined as the failure to eradicate the tumor. This immunosuppressed state is generally associated with decreased numbers and reactivity of lymphoid cells in women with ovarian cancer. The degree of immune dysfunction in ovarian cancer patients has been demonstrated to correlate with patient survival. While ovarian cancer patients generally fail to exhibit effective immunosurveillance, as manifested by continued tumor growth and progression, the presence of tumor-reactive immunoglobulins can be demonstrated in these women, indicating the continued presence of immune recognition. We have not only demonstrated the presence of tumor-reactive antibodies in ovarian cancer patients, but have also shown that the levels of these antibodies increase as the disease progresses. The antigens recognized by the patients' humoral response have been identified as either membrane-associated or intra-cellular. In general, the localization of these antigens tend to be linked to the patient's prognosis. The presence of a humoral response against intracellular proteins are correlated with poor prognosis, while autoantibodies reactive with surface components appear to have a better prognosis. In addition to general antigen recognition, these reactive antibodies have been utilized to define specific epitopes on tumor-associated proteins. Certain specific antigenic epitopes exhibit common recognition among patients with the same tumor type. The specific recognition of certain epitopes can provide early evidence of aberrant protein expression and this aberrant expression of certain proteins, such as procathepsin D, appear to be linked to the tumor's acquisition of specific malignant characteristics, including metastasis formation and chemoresistance. Despite the existence of circulating tumor-reactive immunoglobulins, their presence correlates, in general, with poor prognosis and poor host survival. Since tumor-reactive immunoglobulins are elicited and can be detected early in the development of tumors and their enhanced synthesis is induced prior to the clinical manifestation of recurrence, the assessment of the tumor-reactive immune response against specific antigenic epitopes should represent an early significant diagnostic and prognostic marker in ovarian cancer.     

Effects of feeder cells (human cancer cell lines) on the development of mouse embryos by co-culture

The participation of apical membranes of uterine epithelial cells in the process of blastocyst adhesion makes them an interesting object in the study of changes occurring during early pregnancy. In the study of these changes alkaline phosphatase (AIP), a typical brush border enzyme, was chosen for demonstration with the scanning electron microscope (SEM) by means of a backscatter detector. Thus the temporal and spatial pattern of enzyme activity on the uterine luminal surface was made visible with lead salt procedures. AIP activity was shown to be located on apical membranes and microvilli of endometrial epithelial cells with high activity on day 2 of pregnancy decreasing to virtually no activity on day 5. This decrease in overall AIP activity was shown to be asymmetrical with respect to the uterine cavity. It begins on the antimesometrial half of the uterine lining on day 2. A distribution pattern demarcating a presumptive implantation site along the uterine horn was not found. However, on day 5 of pregnancy, a characteristic pattern of surface folds was found, dividing the uterine horn into 'implantation segments'. In addition, SEM investigation revealed a marked variation of AIP activity from one individual cell to the next on day 2 of pregnancy resulting in a mosaic-like pattern. This pattern is lost with the decrease of AIP activity on day 5. Thus heterogeneity of uterine epithelial cells in AIP activity is apparently a feature of nonreceptive epithelium in contrast to the homogeneous epithelium on day 5. It is proposed that epithelial cell homogeneity could be a marker for uterine receptivity.     

Effect of the method of production of porous powder metallurgy materials on their capillary properties (review)

The unique features of liquid infiltration in capillary porous powder metallurgy materials (CPPM) are discussed. The effect of the production method on the maximum height and rate of capillary rise of a liquid in CPPM is clarified. It is shown that in materials with a uniform pore structure, and the same average pore size, the maximum value of H_max is attained when the form factor of the initial powder particles is a minimum. The highest values of liquid infiltration rate at closely similar heights of capillary rise (within 5–7%) were obtained in CPPM with a variable pore distribution prepared from mixtures of powders with dtiferent particle sizes (pseudo fluidization method), or in CPPM with a biporous structure prepared by the sintering of a previously oxidized powder, by compacting metal powder with a pore forming agent, as well as by the cathodic deposition of a porous copper structure from electrolytic solution.Scientific Research Institute for Powder Metallurgy, Minsk. Translated from Poroshkovaya Metallurgiya, Nos. 5–6, pp. 30–39, May-June, 1996. Original article submitted July 14, 1994.     

Effect of oyster mushroom (Pleurotus ostreatus) on pathological changes in dimethylhydrazine-induced rat colon cancer

The effect of 5% of dried oyster mushroom (Pleurotus ostreatus) in the diet on the dimethylhydrazine (DMH)-induced colon carcinogenesis was studied in male Wistar rats. DMH in a dose of 20 mg/kg of body weight was applied to animals once a week during a period of 12 weeks. Mushroom diet was applied either after treatment with DMH for another 21 weeks or during the whole experiment. Mushroom diet reduced significantly the incidence of lymphoid hyperplasia foci when mushroom was supplemented during the whole experiment. Tumour lesions could be characterized either as carcinoma in situ, or as infiltrating adenocarcinoma. Mushroom diet did not affect significantly the incidence of tumours. Nevertheless, a reduction in total number of tumours was observed in both groups of animals fed mushroom diet. A significant reduction of the number of tumour foci of the type carcinoma in situ was observed in animals fed the oyster mushroom during the whole experiment. Also these animals had the significantly lower number of aberrant crypt foci. Mushroom diet reduced the ornithine decarboxylase activity in the colon and in the liver when oyster mushroom diet was administered during the whole experiment.     

Physicochemical interaction and structure development during the formation of metal gas-transport coatings on diamond (review) II. Mechanism

Formation of chromium, titanium, molybdenum, vanadium, and tungsten coatings on diamond under various metallizing conditions and with different phase compositions of the metal sprays is studied. In the initial stages this process is controlled by the interaction of the diamond (carbon) surface with metal oxides through the gas phase as well as by diffusion of the metal spray. After formation of a continuous layer further coating growth is controlled by carbon diffusion. A reduction in the rate of mass transfer to the reaction surface and the rate of carbon yield from it are factors which limit coating growth. The former is connected with depletion of the metal spray; with a decrease in volatile phase flow, and reduction of MoO₃, V₂O₅, and WO₃, as well as with their removal during pumping; a reduction of the dissociation and disproportioning rate of the oxides; retardation of metal ion diffusion in the metal spray and appearance of oxides (V₂O₃, VO, Ti₂O₃, TiO, etc.) in it which interact weakly with carbon. Emergence of carbon at the surface is specified by its inhibition under diffusion in the growing layer of the coating, filling of carbon vacancies in carbide (TiC, VC) lattices, carbidization of metal, and transformation of lower carbides into higher forms.Translated from Poroshkovaya Metallurgiya, No. 8 (356), pp. 57–63, August, 1992.