Formation of deletional derivatives of the Ti-plasmid pGV3850 in a conjugative transfer from Agrobacterium tumefaciens to Escherichia coli

The process of the transfer of the Ti-plasmid vector pGV3850 with the plasmid pBR322 inserted into the T-DNA region from Agrobacterium tumefaciens to a non-plasmid strain of Escherichia coli was studied. The transferred Ti-plasmid was found to be exposed to deletions and formed a wide range of derivatives with a size ranging from 3-4 kb to 50 kb, maintained in E. coli due to ColE1-replicon. The Ti-plasmid is also inserted into the chromosome of the recipient bacterium with at least a 100-fold lower frequency than the formation of deletional derivatives. It was shown that the induction of vir genes controlling the transfer of T-DNA into plants has no appreciable effect on the efficiency of obtaining transconjugates in mating with E. coli. The deletion of the genetic material of megaplasmids with the inserted functional site OriV ColE1, as a result of the conjugative transfer from cells of different bacteria to the cells of E. coli, was proposed for molecular cloning.     

Topological characteristics of chromatin in a cell-free system from Drosophila embryos

BACKGROUND: Vasoactive intestinal polypeptide (VIP)-secreting tumors of the pancreas represent a rare subtype of pancreatic islet cell tumors with an estimated incidence of 0.2 to 0.5 per million per year. We provide data on a relatively large series of patients with VIP-secreting tumors and review current literature regarding this specific entity. METHODS: A retrospective review was performed of all patients with VIP-secreting tumors of the pancreas treated from 1977 to 1992 at our institution. Presenting signs, symptoms, mode of diagnosis, extent of disease, surgical resectability, tumor size, treatments, hormone levels, and survival were assessed. RESULTS: Eighteen patients were identified, 9 male and 9 female. Ages ranged from 23 to 74 years (mean 51 years). Secretory diarrhea was the most common symptom, occurring in 16 of 18 patients (89%). The most common tumor location was the tail of the pancreas (9 patients). Fourteen patients (78%) had liver metastasis at diagnosis. Curative resections were attempted in only 5 patients (28%). The mean survival was 3.6 years with the longest disease-free survival being 15 years and longest overall survival 15 years. CONCLUSIONS: VIP-secreting tumors are extremely rare entities and usually metastatic at the time of diagnosis. Despite advanced disease, these patients can have extended survival.     

Carcinoma of the stomach following the Chernobyl nuclear accident

Medical consequences of many nuclear accidents on humans are well studied, but the results pertaining to gastric cancer patients who were exposed to radiation as a result of the Chernobyl nuclear accident have not been analysed. In this study, the outcome of the surgical treatment of 68 gastric cancer patients who were exposed to radiation as a result of the Chernobyl nuclear accident was compared with that of 117 consecutive gastric cancer patients from uncontaminated areas of the Ukraine. Patients in the study group was significantly younger than that of the control group. Comparative analysis showed the same frequency of regional metastases (65.7% versus 71.1%, P > 0.05), but a smaller number of distant metastases (23.8% versus 38.1%, P < 0.05) in the study group. 41.2% of patients in the study group underwent total gastrectomy compared to 19.6% of patients in the control group (P = 0.002). Postoperative complications developed in 13.2% of patients in the study group, while postoperative mortality in the study group was 7.3% compared to 1.7% in the control group. A significant decrease in CD16 cells was noted in patients from the study group following the operative procedure. Young age, invasive tumours with smaller number of distant metastases, frequent necessity for total gastrectomy and combined operations with adjacent organs, a higher level of postoperative morbidity and mortality and low levels of natural killer cells (CD16+) with a tendency to decrease after surgery are characteristic of patients with carcinoma of the stomach affected by the Chernobyl accident.     

Young children's understanding of the cognitive verb forget

Investigation of children's understanding of the cognitive verb forget has shown that young children do not consider the role of prior knowledge when using this verb. Thus, someone may be said to have forgotten a fact despite not ever having previously known it. However, forget can also be used to refer to a failure to recall a prior intention. Three experiments examined the role of prior intention as well as prior knowledge in the comprehension of forget by 160 young children aged four to eight years. The results showed that children initially have two interpretations of forget: as an unfulfilled desire rather than a failure to recall a prior intention, and as a state of not knowing rather than a failure to recall prior knowledge. Explanations for the late comprehension of forget are discussed in terms of representation of knowledge and intention, processing capacity and exposure to pragmatic usages.     

Interaction of actinomycin D with suspended mycelium of streptomyces

Binding of exogenous actinomycin D (AMD) by washed mycelium of streptomycetes i.e. variants of Streptomyces chrysomallus producing and not producing actinomycins and Streptomyces lividans not synthesizing the antibiotics was studied. Dependence of the bound quantity of AMD on its concentration, incubation time and temperature, energy source availability, influence of respiration inhibitors and the membranotropic antibiotic gramicidin S was shown. The intracellularly localized portion of the bound AMD likely penetrated to the cells by diffusion and was strongly bound presumably to DNA in the AMD sensitive S.lividans and to the specific intracellular actinomycin-binding proteins in the AMD resistant variants of S.chrysomallus. The ratio of AMD strongly bound by the mycelium and AMD easily washed with physiological solution and probably localized on the surface was determined. The ratio depended on sensitivity of the culture to AMD and for the variants of S.chrysomallus on the age of the culture and its ability to synthesize actinomycins.     

Dynamics of indicators of blood inorganic phosphorus during gastrointestinal surgery

BACKGROUND: There is a more and more interest regarding methods of obstetric analgesia and anesthesia while there is a lack of epidemiological data about local experiences. METHODS: This survey on obstetric anesthesia and analgesia in Abruzzo and Molise is based on data obtained from questionnaires of 28 questions sent to all the departments of anesthesiology in the two regions. DISCUSSION: Out of 24 questionnaires sent, 18 were returned. By analysing the replies obtained in this investigation it is clearly pointed out how the possibility of having peridural analgesia during labor is often not available. In fact, only one center is able to guarantee an operative service 24 hours a day. Many colleagues have reported this deficit and in order to improve the situation they have proposed to activate chargeable services for labor analgesia and to increase the staff of anesthetists. Also the data concerning treatment of post vaginal delivery pain are not satisfactory. With regard to the Caesarean sections, locoregional anesthesia is performed in 24% of all cases, while the highest scores are registered in the hospitals of Castel di Sangro and L'Aquila, where general anesthesia is practically never employed. Merely in 67% of all patients postoperative analgesia is carried out on a regular basis. CONCLUSIONS: The data obtained only confirm the extent of a well-known problem. In spite of the growing interest by the medical community, the attention shown for obstetric anesthesia and analgesia is, nevertheless, insufficient, especially due to financial and organizational problems which prevent from establishing a permanent pain therapy center.     

The genetic sequelae for plant populations of radioactive environmental pollution in connection with the Chernobyl accident

Populations of Arabidopsis thaliana (L.) Heynh., and Pinus sylvestris L., growing within 30 km of Chernobyl and Bryansk region have been analyzed for the frequency of embryonic lethal mutations on Arabidopsis and frequency of chlorophyll mutations and chromosome aberrations by pine. On pine also have been analyzed rate of mutations at enzyme loci in endosperms of seeds. Dose dependence of the value genetic damage on level of radioactive pollution was observed.     

Compound heterozygous deletion of the PROP-1 gene in children with combined pituitary hormone deficiency

Mutations in the prophet of Pit-1 gene (PROP1) have been shown to be responsible for combined pituitary hormone deficiency (CPHD) with deficiencies of growth hormone (GH), Prolactin (Prl), thyroid-stimulating hormone (TSH) and gonadotropins. We previously reported that homozygosity for a 2bp deletion in exon 2 (296delGA) accounted for CPHD in three patients from two Russian families. Here we report a second mutational hot spot in exon 2. This 2bp 149delGA deletion results in a frame shift that leads to the same serine to stop codon change at codon 109 (S109X). The predicted proteins are each truncated at residue 108 but diverge from the wild type sequence at different points in the homeodomain. Compound heterozygosity for the two mutations (149delGA/296delGA) was detected in 5 of 14 CPHD children from 4 families (36%). This provides the first evidence of heterozygosity for two common deletions as a cause of CPHD in Russian children.