Analysis of a defect in the H-2 genes of SV40 transformed C3H fibroblasts that do not express H-2Kk

C3H fibroblasts transformed in vitro with SV40 were adapted to in vivo growth. Several clones were isolated from a single, highly oncogenic tumor and those that displayed oncogenic potential also no longer expressed the H-2Kk molecule. Using the technique of Southern blot hybridization, the H-2 genes and integrated SV40 sequences present in the genomic DNA of several of these clones have been examined and compared with both the parent line and normal liver genomic DNA from C3H mice. All H-2Kk negative clones had altered H-2 genes that appeared as a gain and, depending on the restriction endonuclease, loss of hybridizing fragments compared to normal C3H DNA. A 5.5-kb fragment missing from the Sstl digests of the H-2Kk negative variants was mapped to the H-2Kk region of the major histocompatability complex with the use of congenic mice. This provided direct evidence that a mutation had occurred in the H-2Kk region. The integrated SV40 sequences were similar to those already seen in other SV40 transformed cells and not closely linked to any of the H-2 genes. There was no indication that the H-2 mutation was caused by integration of SV40.     

Ovum transport in cyclic rats rendered hypo-oestrogenic by treatment with 4-hydroxy-4-androstene-3,17-dione

The effects of decreasing oestrogen secretion upon the rate of oocyte transport achieved by the administration of 4-hydroxy-4-androstene-3,17-dione were investigated in cyclic rats. Control animals examined during late pro-oestrus showed that the majority of oocytes had entered the uterus. In contrast, when inhibitor was administered from the afternoon of metoestrus or from late dioestrus through prooestrus, oviducal retention of oocytes was observed. When treatment was delayed until the morning of pro-oestrus, only uterine retention of oocytes was observed. The inhibitor decreased oestradiol concentrations in ovarian vein, while systemic testosterone values were increased. Treatment with exogenous oestradiol counteracted the effect of the inhibitor on ovum transport. The elevation of systemic testosterone concentrations by means of subdermal implants of testosterone failed to alter the normal pattern of ovum transport. These results demonstrate that normal oestrogen secretion during late metoestrus and dioestrus is required for the movement of oocytes from the oviduct to the uterus, whereas the preovulatory oestrogen surge is needed for the expulsion of ova from the uterus.     

Errata

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Comparative analysis of NADPH-diaphorase positive neurons in the rat, rabbit and pheasant thoracic spinal cord. A histochemical study.

The distribution of NADPH-diaphorase (NADPH-d) activity was investigated and compared in the rat, rabbit and pheasant thoracic spinal cord. The investigation of all spinal cord regions (laminae) in three experimental species revealed marked differences in the distribution of NADPH-d activity. Cross sectional analysis of the spinal cord of the rat, rabbit and pheasant confirmed differences in the shape of the gray matter in all examined species. More detailed investigation of Rexed's laminas showed similar distribution of NADPH-d activity in the spinal cord of the rat and rabbit, which were different when compared with the spinal cord of the pheasant. Ventral horn of the rat and rabbit showed no labelling whereas in pheasant this area possessed a number of scattered, intensively stained neurons. In the location of autonomic preganglionic neurons, differences were found as well. In the rat there was seen a number of densely packed, clearly dark blue coloured neurons. Similarly, these neurons were present in the rabbit spinal cord but they were less numerous. No staining was found in this region of pheasant. Pericentral area (lamina X) and intermediate zone (laminaVII) revealed the presence of NADPH-d positive neurons in all examined species although they differed in number and shape of their bodies. The dorsal horn showed the presence of NADPH-d staining in all three animals but its distribution was different in medio-lateral direction. It can be suggested that observed differencies in the presence and distribution of NADPH-d activity across the examined species may reflect different fylogenetic development.     

Force field development on pigments of photosystem 2 reaction centre

We developed new parameters for molecular dynamics (MD) simulations, namely partial atomic charges, equilibrium bond-lengths, angles, dihedrals, atom types, and force constants of chlorophyll a (Chl) and plastoquinone (PQ), and both reduced and neutral form of primary acceptor (PHO) molecule. These parameters are essential for MD simulations that can interpret various structure functional relationships during primary processes of charge separation and stabilization in photosystem 2 reaction centres.     

Changes in acute phase proteins after anti-tumor necrosis factor antibody (infliximab) treatment in patients with Crohn's disease

Acute phase proteins and markers of proteosynthetic activity reflect the clinical activity in Crohn's disease (CD). The impact of anti-tumor necrosis factor antibody (anti-TNF) therapy on serum levels of acute phase proteins and proteosynthetic markers was studied. Fourteen patients with active CD were treated with 5 mg per kg of anti-TNF in intravenous infusion. Clinical activity (assessed by Crohn's disease activity index - CDAI), alpha-1-acid glycoprotein, haptoglobin, cholinesterase and prealbumin were assessed before and in months 1 and 5 after treatment. A sustained decrease in CDAI was observed. This was accompanied by a significant decrease in alpha-1-acid glycoprotein and haptoglobin in month 1 (p=0.005 and p=0.01, respectively) while in month 5 the levels of both acute phase proteins rose significantly (p=0.003 for alpha-1-acid glycoprotein and p=0.02 for haptoglobin). Cholinesterase and prealbumin significantly increased in month 1 after the treatment (p=0.02 and p=0.0006, respectively), the increase was sustained in cholinesterase while prealbumin levels diminished in month 5. We conclude that the clinical improvement after anti-TNF therapy for CD is accompanied by changes of acute phase proteins and proteosynthetic markers. The assessment of these laboratory markers may be useful in the management of CD patients treated with anti-TNF.     

Modulation of tyramine signaling by osmolality in an insect secretory epithelium

The control of water balance in multicellular organisms depends on absorptive and secretory processes across epithelia. This study concerns the effects of osmolality on the function of the Malpighian tubules (MTs), a major component of the insect excretory system. Previous work has shown that the biogenic amine tyramine increases transepithelial chloride conductance and urine secretion in Drosophila MTs. This study demonstrates that the response of MTs to tyramine, as measured by the depolarization of the transepithelial potential (TEP), is modulated by the osmolality of the surrounding medium. An increase in osmolality caused decreased tyramine sensitivity, whereas a decrease in osmolality resulted in increased tyramine sensitivity; changes in osmolality of ±20% resulted in a nearly 10-fold modulation of the response to 10 nM tyramine. The activity of another diuretic agent, leucokinin, was similarly sensitive to osmolality, suggesting that the modulation occurs downstream of the tyramine receptor. In response to continuous tyramine signaling, as likely occurs in vivo, the TEP oscillates, and an increase in osmolality lengthened the period of these oscillations. Increased osmolality also caused a decrease in the rate of urine production; this decrease was attenuated by the tyraminergic antagonist yohimbine. A model is proposed in which this modulation of tyramine signaling enhances the conservation of body water during dehydration stress. The modulation of ligand signaling is a novel effect of osmolality and may be a widespread mechanism through which epithelia respond to changes in their environment. Drosophila; Malpighian tubule; cell volume regulation; G protein-coupled receptor; biogenic amines