Differential microbial clearance and immunoresponse of Balb/c (Nramp1 susceptible) and DBA2 (Nramp1 resistant) mice intracerebrally infected with Mycobacterium bovis BCG (BCG)

In mice, the gene encoding Nramp1 (natural resistance-associated protein 1) exists in two allelic forms, differing for a point mutation. According to Nramp1 genotype, extensive literature documents a clear-cut distinction of inbred strains in two non-overlapping groups that phenotypically express resistance (Nramp1r) and susceptibility (Nramp1s) to systemic infections. Here, we provide evidence that Nramp1r (DBA/2) and Nramp1s (Balb/c) mice differently handle intracerebral infection with Mycobacterium bovis BCG. Distinct trends of microbial clearance from the brain and also different patterns of local immune responses occur, thus arguing on the involvement of Nramp1 gene product on the accomplishment of cerebral anti-mycobacterial defenses.     

Epididymal cribriform hyperplasia with nuclear atypia in p53 homozygous knockout mice on a mixed 129/Sv-FVB/N background

Epididymal cribriform hyperplasia (ECH) is a variant of normal epididymal histologic features in men, and has also been reported in rats, mice, dogs, cats, and bulls. The epididymal change has been associated with aging, testicular atrophy, cryptorchidism, and germ cell tumors. Epididymal cribriform hyperplasia was observed in p53 homozygous knockout mice on a mixed 129/Sv-FVB/N background, but not in wild-type or heterozygous mice. The aim of the study reported here was to determine the prevalence and characterize the morphologic, immunohistochemical, and ultrastructural features of ECH in these mice. Epididymal cribriform hyperplasia was present in 88% (72/82) of male mice ranging in age from seven to 65 weeks. The lesion was characterized microscopically by epithelial cells with atypical hyperchromatic nuclei, vacuolization, intratubular lumina formation, infrequent apoptosis, and rare mitotic figures. In contrast to germ cells, the cells of ECH did not express alpha-fetoprotein, carcinoembryonic antigen, or S-100. Ultrastructurally, the cells were pleomorphic with stereocilia at their apical borders and within intratubular lumina, and were supported by a basement membrane. Although 14% (10/72) of mice had concomitant testicular neoplasia, ECH did not appear to be a preneoplastic change. Investigators using these mice for modeling human disease should be aware of the background prevalence of this lesion.     

Ligand-induced changes in the binding sites of proteins

Classical molecular interaction potentials, in conjunction with other theoretical techniques, are used to analyze the dependence of the binding sites of representative proteins on the bound ligand. It is found that the ligand bound introduces in general small structural perturbations at the binding site of the protein. However, such small structural changes can lead to important alterations in the recognition pattern of the protein. The impact of these findings in docking procedures is discussed.     

beta-Endorphin modulation of pressor response to hyperventilation in hypertensive patients

After hyperventilation, systolic and diastolic blood pressure (BP) significantly decreased in 14 hypertensive patients (group 1), did not change in 9 (group 2) and increased in 8 (group 3). Basal BP, norepinephrine and dynorphin B levels were higher in group 1 than in groups 2 and 3. The decrease in BP after hyperventilation was associated with a decrease in plasma norepinephrine, Met-enkephalin and dynorphin B and an increase in beta-endorphin. Naloxone abolished the hyperventilation-induced BP and norepinephrine decreases. Our findings indicate that hyperventilation may select hypertensive patients with different sympatho-adrenergic activity and that the increase in beta-endorphin reduces BP response to hyperventilation in patients with high sympatho-adrenergic tone.     

Complications of microsurgical reconstruction of obstetrical brachial plexus palsy

The charts of the 173 consecutive patients who underwent microsurgical reconstruction for obstetrical brachial plexus palsy from 1988 to 1999 (inclusive) in the Division of Plastic Surgery at the Hospital for Sick Children were analyzed. The overall complication rate was 33.5 percent, and there was no mortality in this series. The most significant intraoperative complication was accidental extubation, which occurred five times in the first 84 patients (6 percent of this early group; 2.9 percent of the whole series). This complication was addressed by suturing the endotracheal tube to the membranous septum and by using a transparent drape to allow direct visualization of the tube in all 89 subsequent patients. There have been no further accidental extubations. Postoperative fluid overload occurred in 14 patients (8.1 percent), three (1.7 percent) of whom developed pulmonary edema. Intensive care unit admission was required in two of those patients. Diuretic treatment was required in seven patients. No patient receiving less than or equal to 4 ml/kg/hour developed fluid overload, whereas 50 percent of the patients receiving greater than or equal to 10 ml/kg/hour did. Currently, the authors' policy is to strictly limit intravenous maintenance fluids to 4 ml/kg/hour or less. Despite the long and complex procedure required to reconstruct obstetrical brachial plexus palsy, the incidence of significant complications can be minimized with simple precautions, such as suturing the endotracheal tube to the septum or reducing the amount of fluids administered during the operation.     

Archaeobotanical investigations in Liguria: preliminary data on the early Iron Age at Monte Trabocchetto (Pietra Ligure,Italy)

The archaeological site we studied is part of an early Iron Age hill fort (8th/7th cent. b.c.), located 800 m from the coast on the top of a hill named MonteTrabocchetto. This paper concerns an excavation, called saggio O, which disclosed a very varied stratigraphy characterised by highly anthropogenic layers and by a pit, presumably used as a silo for food storage, which was very rich in charred seeds and fruits. The study of the pit content showed the dominance of Hordeum vulgare, while Triticum dicoccon, T. monococcum, T. aestivum/durum, Panicum miliaceum and Setaria italica were less strongly represented. Some edible Leguminosae were also found (Lens culinaris, Vicia faba var. minor and V. ervilia). In the frequented areas around the pit, herbaceous weeds and fruit tree macro-remains were present (Prunus cf. spinosa, Corylus avellana, Quercus sp. and Vitis vinifera ssp. sylvestris). The identification of a large number of botanical taxa has provided important information on food of plant origin and agricultural practices during the early Iron Age on the Ligurian coast, the proto-historic archaeobotanical aspects of which are largely unknown.     

Comparative genetic analysis of the hexaploid wheat Triticum petropavlovskyi Udasz. et Migusch. and Triticum aestivum L

A poorly studied species of hexaploid wheat Triticum petropavlovskyi Udacz. et Migusch. was compared with common wheat Triticum aestivum L. by means of monosomic and genetic analyses of F2 hybrids. Triticum petropavlovskyi was found to carry 13 dominant genes determining its morphological and physiological characters and regular bivalent conjugation of chromosomes. These genes were allelic to the respective genes of common wheat and were located in the same chromosomes. The modes of gene interaction were also the same. There was simple dominance for most genes studied and complementary interaction for the genes of hybrid dwarfism and hybrid necrosis. Triticum petropavlovskyi had the following dominant genes: Hg (downy glume); Rg1 (red glume color); Hl (downy leaf); Hn (downy node); Pa (pubescent auricles); Q (speltlike ears); D1 (grass-clump dwarfism); Ne1 (hybrid necrosis); Ph1 and Ph2 (genes of bivalent conjugation preventing homoeologous chromosomes from pairing); and Vrn1, Vrn2, Vrn3, and Vrn4 (genes of the spring habit). The gene Vrn1, which caused an increase in ear emergence time and a pronounced response to vernalization, was poorly expressed. T. petropavlovskyi was earlier demonstrated to have a species-specific gene P or Eg (elongated glume), which was not allelic to the gene Eg of the tetraploid T. polonicum L. The data obtained indicate that T. petropavlovskyi has originated from T. aestivum via mutations.     

5'-nicked apurinic/apyrimidinic sites are resistant to beta-elimination by beta-polymerase and are persistent in human cultured cells after oxidative stress

Genomic DNA is continuously exposed to oxidative stress. Whereas reactive oxygen species (ROS) preferentially react with bases in DNA, free radicals also abstract hydrogen atoms from deoxyribose, resulting in the formation of apurinic/apyrimidinic (AP) sites and strand breaks. We recently reported high steady-state levels of AP sites in rat tissues and human liver DNA (Nakamura, J., and Swenberg, J. A. (1999) Cancer Res. 59, 2522-2526). These AP sites were predominantly cleaved 5' to the lesion. We hypothesized that these endogenous AP sites were derived from oxidative stress. In this investigation, AP sites induced by ROS were quantitated and characterized. A combination of H(2)O(2) and FeSO(4) induced significant numbers of AP sites in calf thymus DNA, which were predominantly cleaved 5' to the AP sites (75% of total aldehydic AP sites). An increase in the number of 5'-AP sites was also detected in human cultured cells exposed to H(2)O(2), and these 5'-AP sites were persistent during the post-exposure period. beta-Elimination by DNA beta-polymerase efficiently excised 5'-regular AP sites, but not 5'-AP sites, in DNA from cells exposed to H(2)O(2). These results suggest that 5'-oxidized AP sites induced by ROS are not efficiently repaired by the mammalian short patch base excision repair pathway.     

Cell-mediated DNA transport between distant inflammatory sites following intradermal DNA immunization in the presence of adjuvant

After intradermal genetic immunization, naked DNA is transported from the site of injection to regional lymph nodes. Little is known on how inflammation influences this process and whether DNA is transported beyond local lymph nodes. In the experiments herein reported, we injected naked DNA in the presence of adjuvant to address questions related to 1) the fate of naked DNA in the presence of inflammation; 2) the generation of immune responses to the encoded protein during inflammation; and, more in general, 3) the fate of ingested molecules beyond regional lymph nodes during inflammation. Two sites of inflammation were induced in vivo in mice. Naked DNA was injected in the nape together with adjuvant, and adjuvant only was injected at a distant peritoneal site. Injected DNA, uptaken at the primary dermal site of inflammation, was transported beyond regional lymph nodes to distant organs such as the spleen and to the distant peritoneal site of inflammation. This transport, mediated by CD11b+ cells, was cumulative during chronic inflammation. These results indicate a novel route of transport of DNA beyond regional lymph nodes and may have specific implications for DNA-based immune modulation.     

Solution 1H NMR study of the heme cavity and folding topology of the abbreviated chain 118-residue globin from the cyanobacterium Nostoc commune

The globin from the cyanobacterium Nostoc commune, abbreviated GlbN, which appears to serve as a part of a terminal oxidase rather than as a respiratory pigment, displays relatively normal O2 binding properties, despite the highly abbreviated polypeptide chain, (118 residues) relative to more conventional globins [Thorsteinsson, M. V. , Bevan, D. R., Potts, M., Dou, Y., Eich, R. F., Hargrove, M. S., Gibson, Q. H., and Olson, J. S. (1999) Biochemistry 38, 2117-2126]. The nature of the heme cavity and the general folding topology of this cyanoglobin were investigated by solution 1H NMR to establish the extent to which, and the manner in which, this compact globin adheres to the standard globin fold. This represents by far the smallest globin subjected to structural analysis. The paramagnetic cyanomet derivative was selected because its characteristically large magnetic anisotropy imparts significant dipolar shifts which both improve resolution to greatly facilitate assignments and serve as indicators of the folding topology of the globin. Identification of the axial His 70 and highly conserved Phe 35 (CD1) determined the absolute orientation of the heme and proximal His. Sequential assignments of four helical and one loop segments, which exhibit dipolar contacts to the heme and among each other, confirm the presence of well-conserved F, G, and H helices and the FG corner. The majority of the abbreviation of the chain relative to the more conventional length globins is accommodated in the A-D helices, of which the last is completely missing. The distal residue which provides a H-bond to bound ligand is identified as Gln 43, but the expected helical position E7 could not be confirmed. His 46, placed at position E10, is found to adopt alternate orientations into, and out of, the heme cavity depending on protonation state, suggesting the presence of a Bohr effect at low pH. It is shown that the dipolar shifts exhibited by backbone protons for the assigned residues conform well to those observed for other cyanomet globins and further support a conserved Mb fold. Perturbed medium-range dipolar contacts and the pH-independent backbone proton lability of the F helix are interpreted in terms of a holoprotein which is less stable than a conventional length globin.