Molecular mechanisms of carcinogenesis: the role of systems of DNA repair

The initiation step of the carcinogenic process consists in an alteration of genes playing a central role in the cellular life. The next steps of promotion and progression result from anomalies in the response to growth factors, to hormones and/or from the action of tumor promotors leading to cellular hyperplasia. This process generally leads to genetic instability of the initiated cell which in turn allows selection of malignant and invasive clones. The production of DNA damage by physical or chemical agents is dose-dependent. The error-free enzymatic repair processes including excision resynthesis of base damage or of altered nucleotides allow the restitution of intact DNA. The error-prone repair systems permit survival in association with transmissible alterations (genes and chromosomal mutations). Absence of repair leads to cytotoxicity, programmed cell death or disruption of cell cycle control leading to a pretumoral state. The major role played by mutations in the initiation of carcinogenesis is evidenced by the existence of genetic syndromes associated to hypersensitivity to genotoxic agents, defects in DNA repair capacity, anomalies in the expression of certain genes (including the tumor suppressor p53 gene, etc.) and an elevated predisposition to cancer. Xeroderma pigmentosum which is defective in excision-repair, ataxia telangiectasia and Fanconi anemia which are associated to anomalies in DNA recombination and the familial type of colon cancer HPNCP due to inefficient mismatch repair constitute paradigm for this fundamental notion. Alterations in the capacity to rejoin radiation induced DNA strand breaks appears to be associated to over-reactions to radiotherapy of cancer patients. Also the predisposition to develop secondary thyroid tumors following treatment of a primary cancer in childhood seems to involve the same defect. The existence in the general population of heterozygotes for such DNA repair genes should be taken into account for risk evaluation to therapeutic and environmental exposures.     

Effectiveness of complex sanatorium-climatic treatment of patients with recurrences of pulmonary tuberculosis

From the point of view of social hygiene is shown, in what way social conditions are given and sued in the GDR to take influence on the state of health up to old age. As main factors of work dwelling and social or cultural care are considered. Resuming his treatise the author confirms that not yet all sources are used to solve the problems regarded. References to law-materials and other principles are given to support physicians in treating and guiding older people and to enable authorities not belonging to health service to fulfill the adequate tasks.     

Aspects of transport of pet animals

BACKGROUND: Neonatal risk in herpes infections is very high: in the USA it is 1:2,000, in Japan 1:15,000 and in England 1:65,000. These differences seem to be due mostly to the different risk factors associated to the mother infection. The best strategy to cure herpes infection is to examine every patient during pregnancy and to identify the high risk ones. METHODS: In this study, 1,860 pregnant women have been submitted to a colposcopic and cytologic screening for the research of HSV. RESULTS: HSV was found in twenty (1.07%) women. Two groups have been made: the first with 14 HSV positive women at 3-6 months of pregnancy and second with 6 HSV positive women at eight months of pregnancy. Both groups were treated with acyclovir per os. The 14 women of the first group underwent vaginal delivery. The women of the second group underwent cesarean section. Only in 1 case a neonatal infection has been observed.     

Manipulation of the fertility of marsupials for conservation of endangered species and control of over-abundant populations

Marsupials present a dichotomy in population management; the numbers of many Australian marsupial species have declined due to loss of habitat, competition from introduced herbivores and predation by introduced carnivores, but other species have become locally overabundant in Australia or are introduced pests in New Zealand. The manipulation of reproduction offers the means to increase or decrease productivity; however, considerable fundamental research is required before reproductive technologies can be applied to marsupials. Marsupials differ from eutherian mammals in several aspects of their reproduction including sex differentiation, gamete function and endocrinology, as well as in the relative lengths of gestation and lactation. Although these differences present unique problems in the application of reproductive technologies to marsupials, they also present unique opportunities for marsupial-specific fertility control. This paper summarises the assisted breeding technologies currently being applied to marsupials including superovulation, artificial insemination, in vitro fertilization and gene banking; unique marsupial targets for contraceptive intervention including gamete production, sperm capacitation, gamete surface antigens and embryonic development; and some options for the delivery of contraceptive vaccines to marsupial populations.     

Functions of conserved tryptophan residues of the core light-harvesting complex of Rhodobacter sphaeroides

We have examined mutants in the core light-harvesting complex of Rhodobacter sphaeroides in which the tryptophan residues located at positions alpha+11, beta+6, and beta+9 have been mutated to each of the three other aromatic amino acids, namely tyrosine, phenylalanine, and histidine. We confirm that the alpha+11 residue and show that the beta+9 residue each form a hydrogen bond to a C2-acetyl group of a BChl molecule. Mutation of either of these residues to a phenylalanine results in a breakage of the normal hydrogen bond, whereas a histidine in either of these positions is able to form a hydrogen bond to the BChl. Comparison of the absorption spectra with the hydrogen bonding of the C2-acetyl groups for the various mutants demonstrates a role for this molecular interaction in the tuning of the absorption properties of the complex. We further demonstrate that there is a consistent linear relationship between the downshift in the C2-acetyl stretching mode and the red shift in the absorption maximum, in both core and peripheral antenna complexes. This linear relationship allows us to estimate the contribution of H bonding to the red shifts of these complexes. Though the residue beta+6 is found not to be directly involved in interactions with the pigment molecules, mutation of this residue is shown in some cases to result in both a destabilization of the complex and a decrease in the binding site homogeneity. Finally, a consideration of the amount of antenna complex present in the various mutants shows an important role for the reaction center and/or the pufX gene product in the assembly or stabilization of this membrane protein.     

A reconceptualisation of apraxia of speech: a synthesis of evidence

Hippocampal theta activity results from activation in the ascending synchronizing system. It occurs during sensory/signal processing prior to and coincident with voluntary movements in mammals. The experiments summarized here suggest that it is involved in the organization of motor behaviour. (1) Procaine (a local anaesthetic) infused into the medial septum (MS) abolishes hippocampal theta activity and running behaviour elicited by electrical posterior hypothalamic (PH) stimulation. This indicates that movement elicited by PH stimulation, is dependent on ascending hypothalamo-septal circuitry. (2) Theta can also be recorded in immobile rats prior to the initiation of lateral dodging movements they make in response to conspecific rats attempting to steal their food. Following infusion of atropine into the MS, theta recorded during immobility is abolished and the rats are severely impaired at initiating movements in defence of their food. It is suggested that atropine-sensitive theta is involved in the initiation of movements made by rats in response to sensory stimuli. (3) Rats with fimbria-fornix transections were also less likely to engage in lateral dodging movements in defence of their food, were hyperactive, less thigmotaxic, and defecated more often, compared to control animals. Depth profile analysis of hippocampal field activity in lesioned animals revealed an absence of theta during electrical or chemical pons stimulation. These findings provide evidence that these neural systems are involved in signal processing relevant to movements underlying adaptive behaviour.     

Development of children's understanding of ambivalence and causal theories of emotions.

Investigated a 4-stage developmental sequence in children's understanding of ambivalence. At the highest level of this sequence, children understand that contradictory feelings can coexist at the same time toward the same target in terms of a framework in which it is recognized that the 2 feelings influence one another. 20 4–5 yr olds, 20 7–8 yr olds, and 20 10–11 yr olds were presented with 2 tape-recorded stories in which the protagonist could be construed as feeling happy and sad or anger and love. Raters scored the Ss' responses to a structured interview about the stories in terms of the proposed sequence. Separate parts of the protocols were assessed independently with respect to a proposed sequence in children's causal theories of emotions. According to this sequence, children's understanding of feelings develops from an externally based theory in which feelings are wedded to events to an internally based theory in which feelings largely depend on memories, thoughts, and attitudes. Results support both hypothesized developmental progressions and show significant relationships between the 2 domains of Ss' understanding of emotions. Findings suggest that internal states' mediation of emotional responses may be an important component in understanding ambivalence and that the motivation to integrate conflicting feelings may play a role in promoting the external to internal shift in children's causal theories of emotions. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of molinate on growth of five freshwater species of phytoplankton

Hemiarthroplasty is one method used to treat osteoarthritic joints. Often, however, an adverse response of the articular cartilage to the metal implants occurs. The purpose of this study was to evaluate and compare the response of a surgically created defect to pyrolytic carbon and cobalt-based alloy hemiarthroplasties. The cartilage on the lateral side of the tibial plateau of a canine knee joint was abraded to create a full-thickness defect. Two small holes were drilled into the exposed subchondral bone. Next, either a carbon or metal implant was placed in the lateral femoral condyle. The implantation period was 1 year. Histologic examination of the tibial defects revealed a smooth bony surface for both implant groups. In addition, there was no evidence of a residual adverse inflammatory response nor of a significant increase in subchondral bone formation for either group. Surface cracks resulting from the presence of the implant were seen in 14% of the carbon implant specimens and in 100% of the metal implants. Fibrocartilage regeneration was seen in 86% of the carbon implants and in 25% of the metal implants. Thus the carbon appears to be better tolerated mechanically compared to wrought cobalt-chromium alloy. Pyrolytic carbon shows promise for use in hemiarthroplasty.     

Development of the use of sound in the search behavior of infants.

Investigated 48 7–9 mo olds' use of sound to guide their search behavior by presenting Ss with standard object-permanence tasks. The same tasks were then presented to Ss but an object was used that made sound as it was being hidden and continued to make sound from its hiding place. Ss were then presented with a task in which a sound-producing object was surreptitiously hidden and then sounded. Ss began to use sound to direct their search in Stage 4. The use of sound to locate the surreptitiously hidden sound-producing object appeared to come earlier than the use of sound to locate objects in displacement tasks; the use of sound to locate objects in displacement tasks was influenced by the complexity of the displacement. Results suggest that the role of sound in the construction of the object is a developing one that continues well into the 2nd yr of life. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

TNM classification of carcinoma of the esophagus

TNM classification of esophageal carcinoma was first described in the supplement to the first edition of the TNM classification in 1973. In the second edition, the classification was changed based on the data of 1,000 cases from the Task Force on Esophagus of American Joint Committee. In this edition, only the clinical classification was described, but the third edition included both clinical and post-surgical histopathological classification. But the criteria for T and pT classification differed. Before the fourth edition, specialists from Japan and the United States met in Hawaii in 1984. Data of the Japanese Nationwide Registration, including 7,742 patients from 1969 to 1978, were presented. After discussion based on these data, T was classified according to the depth of invasion, and perigastric lymph nodes were included in Regional Nodes in the fourth edition. Then, the TNM Research Committee of ISDE collected patient data of esophageal carcinoma from seven countries, and they were studied according to many factors. Based on these data, two proposals were made to the UICC TNM Committee. First, T1 should be divided into two categories: T1a, Tumor invasion of lamina propria; and T1b, Tumor invasion of submucosa. Second, metastases to distant lymph nodes should be grouped into the N classification instead of M classification. The first was accepted in the TNM Supplement of 1993, and the second will be accepted in the Fifth Edition, which will appear in 1997. It is important to accumulate data on many patients using the uniform registration form and to follow these patients very closely in the discussion of revisions to the TNM classification.     

Analysis of stable low-molecular-weight RNA profiles of members of the family Rhizobiaceae

Staircase electrophoresis in polyacrylamide gels was used to analyze the stable low-molecular-weight (LMW) RNA profiles of 24 type strains belonging to the family Rhizobiaceae. This new electrophoretic technique results in good separation of the molecules forming the LMW RNA profiles. Differences in the number and distribution of the RNA bands in these profiles allowed us to identify differences among the 24 strains assayed. Species assignments based on LMW RNAs proved to be consistent with the established taxonomic classification. Analysis of the data obtained and the corresponding dendrograms revealed relationships between genera and species; these relationships were essentially the same as those obtained with other techniques, such as DNA hybridization and 16S rRNA sequencing. Use of the technique described here, with which it is possible to analyze a large number of strains in a short time, permits rapid identification of species belonging to the family Rhizobiaceae and should in the future facilitate biodiversity studies and detection of new species.     

Folding propensities of peptide fragments of myoglobin

Myoglobin has been studied extensively as a paradigm for protein folding. As part of an ongoing study of potential folding initiation sites in myoglobin, we have synthetized a series of peptides covering the entire sequence of sperm whale myoglobin. We report here on the conformation preferences of a series of peptides that cover the region from the A helix to the FG turn. Structural propensities were determined using circular dichroism and nuclear magnetic resonance spectroscopy in aqueous solution, trifluoroethanol, and methanol. Peptides corresponding to helical regions in the native protein, namely the B, C, D, and E helices, populate the alpha region of (phi, psi) space in water solution but show no measurable helix formation except in the presence of trifluoroethanol. The F-helix sequence has a much lower propensity to populate helical conformations even in TFE. Despite several attempts, we were not successful in synthesizing a peptide corresponding to the A-helix region that was soluble in water. A peptide termed the AB domain was constructed spanning the A- and B-helix sequences. The AB domain is not soluble in water, but shows extensive helix formation throughout the peptide when dissolved in methanol, with a break in the helix at a site close to the A-B helix junction in the intact folded myoglobin protein. With the exception of one local preference for a turn conformation stabilized by hydrophobic interactions, the peptides corresponding to turns in the folded protein do not measurably populate beta-turn conformations in water, and the addition of trifluoroethanol does not enhance the formation of either helical or turn structure. In contrast to the series of peptides described here, either studies of peptides from the GH region of myoglobin show a marked tendency to populate helical structures (H), nascent helical structures (G), or turn conformations (GH peptide) in water solution. This region, together with the A-helix and part of the B-helix, has been shown to participate in an early folding intermediate. The complete analysis of conformational properties of isolated myoglobin peptides supports the hypothesis that spontaneous secondary structure formation in local regions of the polypeptide may play an important role in the initiation of protein folding.     

Investigation of thermodynamic functions of mixing of Fe-Ti melts

The enthalpy of mixing of Fe-Ti melts is studied by high-temperature isoperibolic calorimetry at 1873 K. The experimental data on the thermodynamic functions of mixing in the melts of the system under study are used to calculate the parameters of the ideal associated solution model. This model is employed to simulate the temperature-concentration dependences of liquid Fe-Ti alloys and to find the features of change in their thermodynamic properties.     

Characterization of a second member of the sentrin family of ubiquitin-like proteins

Sentrin is a novel ubiquitin-like protein that can be conjugated to other proteins in a manner analogous to ubiquitination. Two additional cDNA sequences that encode proteins highly homologous to sentrin have been reported to GenBankTM. It is not known whether these sentrin-like proteins could also function as protein modifiers. In this report, a second member of the sentrin family was characterized in detail. Sentrin-2 is a 95-amino acid polypeptide that is 46% identical and 66% homologous to sentrin-1. Northern blot analysis showed that the sentrin-2 message was expressed in all tissues, but was barely detectable in the liver and placenta. The ability of sentrin-2 to conjugate to other proteins was tested by expressing hemagglutinin epitope-tagged sentrin-2 in COS cells. Western blot analysis showed that sentrin-2 could be transferred to other proteins in a pattern similar to that of sentrin-1 conjugation and had similar C-terminal processing. We further showed that both sentrin-1 and sentrin-2 could covalently modify RanGAP1, a Ran GTPase-activating protein critically involved in nuclear transport. Immunocytochemical analysis showed that sentrin-2 derivatives were highly enriched in the nucleus. Taken together, our results demonstrate that sentrin-2 is another protein modifier for the sentrinization pathway.     

Epidemiology of pressure ulcers or the danger of a new Tower of Babel

Pressure epidemiology is a fundamental facet in meeting this important challenge to the health care system. The studies done on epidemiology signify an important effort by their authors, although their validity may be conditioned by methodological and conceptual aspects. The proliferation of studies about pressure epidemiology in our country, some of which having methodological conceptions not in agreement with the existing bibliography about this topic in other countries, make it necessary to gain a grasp of the basic epidemiologic aspects applied to the study of pressures as a health problem. This paper presents a bibliographical review on the subject and states proposals adapted to the characteristics of our immediate environs. This paper includes a review of these concepts: prevalence, incidence, recurrence, and severity; in addition to the most utilized variables in describing the pressure problem. Different strategies for the elaboration of epidemiological studies about pressures are also analyzed. Furthermore, the minimum information which authors of said studies need to facilitate in their reports are mentioned.     

Surgical correction of torsion of the penis

Torsion of the penis is a rare anomaly, believed to be due to abnormal skin attachment and not to any structural abnormality of the corpora. The rotation is usually to the left in a counter-clockwise fashion. The urethral meatus is placed in a oblique position and the median raphe makes a spiral curve from the base of the penis towards the meatus. Three boys with congenital torsion of the penis are reported. A corrective operative for this condition is described. Penile torsion was first described by Verneuil in 1857, but in the past no operative correction was recommended, since attempts to move the skin around were believed not to correct the spiral alignment of the corpora cavernosa.     

Influence of modifiers on the change of mechanical properties of silumins

An increase in the sum of alloying elements in industrial silumins causes the formation of excess intermetallic phases in their structure. When introducing modifiers in such alloys above a certain amount, structural components are coarsened because of overmodification, which can cause a decrease in the mechanical properties of cast alloys. The optimal consumption of the modifying microcrystalline remelt decreases from 0.6 to 0.3 wt % with an increase in the sum of alloying elements in alloys from 7.35% (AK7ch) to 14.3% (AK10M2N). When using the AlTi5 master alloy, the optimal amount of introduced titanium decreases from 0.05 to 0.01% and, in the case of the AlTi5B1 master alloy, from 0.02 to 0.01%. The modifying effect of the AlSr10 master alloy enhances with an increase in the silicon content with smaller amounts of strontium introduced into alloys. It is shown that the consumption of the metallic modifier depends on its modifying ability, as well as the sum of alloying elements in the modified silumin.     

硅钼蓝光度法和滴定法在锰矿石测定中的应用

以混合熔剂熔融试样,用盐酸浸取酸化并还原高价锰,定容后移取部分试液,通过控制测定各元素时的酸度及沉淀分离除去有关干扰元素后,分别用硅钼蓝光度法测定SiO2,EDTA滴定法测定Al2O3,EGTA滴定法和CyDTA滴定法测定CaO和MgO。以盐酸、磷酸溶解试样,用高氯酸酸化,硫酸亚铁铵滴定法测定TMn。实验证明,该方法操作简便、快速,有较好的精密度和准确度,能满足冶金生产的需求。     

Study of the sensitivity of different strians of the influenza A2 virus of rimantadine

The sensitivity of different influenza A2 (H3N2) virus strains to rimantadine in ovo was studied. The reference strains of influenza virus A/Hong Kong/1/68, A/England/42/72, A/Scotland/840/74 as well as new epidemic strains isolated in the USSR and Mongolia in 1974-1975 antigenically related to influenza A/Port Chalmers/1/73 virus were found to be sensitive to rimantadine.