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PubMed1983

[Muscular changes caused by suction drainage. Scanning electron microscopy, transmission electron microscopy, light microscopy and morphometric studies of dorsal muscles of the rat (Rattus rattus) using drainage].

Changes in the dorsal muscles of 22 rats (Wistar), resulting from surgical drain, have been studied under different morphological aspects. The lumen of drains were obstructed after a short time. In the drains without using low pressure, erythrocytes and fibrin network were seen by scanning microscopical investigation. Patent muscle fibres could be analyzed in the lumen of drain using negative pressure. They prevent the functional drain system. By the effect of surgical drains the fibres of dorsal muscles had become swollen. This fact could be analyzed by morphometrical technique. Some changes in fibres have been demonstrated by histological methods.

Animals↗
PubMed1980

Scanning electron, light optical, and transmission electron microscopy and plasma steroid values of porcine uterus at lactation.

Sows, while nursing litters for a period of 4 to 8 weeks, do not ovulate, thereby delaying the time sows can be rebred. Therefore, this study sought to determine how soon after parturition the morphological appearance of the uterus was such that blastocyst implantation could possibly proceed. Biopsy samples taken immediately post-partum and on days 1, 2, 3, 4 post-partum show that the endometrium was considerably damaged as evidenced by sloughing of the zona compacta and zona spongiosa and the presence of leukocytes around the surface epithelial (SE) cells. Around the 6th day post-partum the numbers of leukocytes were reduced and regeneration of the SE was evident. Around the 8th day post-partum, SE cells appeared similar to those of normal cyclic sows in the late luteal phase (i.e. 15 days post-estrum). Under normal breeding conditions, blastocyst implantation takes place during the late luteal phase. From 17 to 26 days post-partum the SE cells appeared similar to those of normal cyclic sows in the early follicular phase (i.e. 21 days post-estrum), and the subepithelial layers seemed edematous. Estradiol and progesterone concentrations dropped markedly at parturition and remained low up to the 26th day of lactation. Although there was considerable heterogeneity of samples between sows it was concluded, from the morphological results, that plasma steroid levels exert relatively little effect on the sow endometrium up to 26 days post-partum. If ovulation could be induced or ova transplant be performed in lactating sows the endometrium would appear ready for blastocyst implantation after day 8 post-partum.

Animals↗
PubMed1995

Free radical formation in single crystals of 9-methyladenine X-irradiated at 10 K. An electron paramagnetic resonance and electron nuclear double resonance study.

Single crystals of 9-methyladenine were X-irradiated at 10 K and at 65 K and were studied using K-band EPR, ENDOR and field-swept ENDOR (FSE) techniques in the temperature range 10 K to 290 K. Three major radicals are stabilized in 9-methyladenine at 10 K. These are: MA1, the adenine anion, probably protonated at N3; MA2, the species formed by net hydrogen abstraction from the 9-methyl group; and MA3, the radical formed by net hydrogen addition to C8 of the adenine moiety. Radical MA1 decayed at about 80 K, possibly into the C2 H adduct (MA4). The other two species (MA2, MA3) were stable at room temperature. A fifth radical species was clearly present in the EPR spectra at 10 K but was not detectable by ENDOR. This species, which decayed above 200 K (possibly into MA3), remains unidentified. The radical population at room temperature is as described by previous authors. The mechanisms for radical formation in 9-methyladenine are discussed in light of the hydrogen bonding scheme and molecular stacking interactions.

Adenine↗
PubMed1996

Radiation damage to DNA base pairs. I. Electron paramagnetic resonance and electron nuclear double resonance study of single crystals of the complex 1-methylthymine.9-methyladenine X-irradiated at 10K.

Single crystals of the complex 1-methylthymine.9-methyl-adenine were X -irradiated at 10 and at 65 K and studied in the temperature range 10 to 290 K using K-band EPR, ENDOR and field-swept ENDOR (FSE) techniques. The EPR and ENDOR spectra are dominated by two major and four minor resonances. The two major resonances are: MTMA1, the well-known radical formed by net hydrogen abstraction fr om the CS methyl group of the thymine moiety, and MTMA2, the radical formed by net hydrogen abstraction from the N1 methyl group of the thymine moiety. The latter product has not been observed previously in any 1-methylthymine derivative. The four minor resonances are: MTMA3, the anion of 1-methylthymine, possibly protonated at the O4 position; MTMA4, the well-known species formed by net hydrogen addition to C6 of the thymine moiety; MTMA5, the species formed by net hydrogen addition to C2 of the adenine moiety; and MTMA6, the species formed by net hydrogen addition to C8 of the adenine moiety. Radical MTMA3, the O4-protonated thymine anion, was clearly detected at 10 K, but upon thermal annealing at 40 K the lines began to disappear. In crystals irradiated at 65 K MTMA3 was only weakly present. Radical MTMA2 decayed at about 250 K with no detectable successor, and radical MTMA5 disappeared at about 180 K. It was not possible to learn from the d ata if MTMA5 transformed into MTMA6. The radical distribution in the 1-methylthymine.9-methyladenine crystal system is different from that in crystals of the individual components. Reasons for this behavior are discussed in light of the hydrogen bonding schemes and molecular stacking interactions in each of the crystals. An important feature is the concept of excited-state transfer from the adenine to the thymine moiety, followed by dehydrogenation at the thymine Nl-methyl group, the mechanism resulting in radical MTMA2.

Adenine↗
PubMed1998

Electron spin resonance and electron nuclear double resonance study of X-irradiated deoxyadenosine: proton transfer behavior of primary ionic radicals.

A study of deoxyadenosine crystals (anhydrous form) after irradiation at 10 K found four base-centered radicals and one sugar-centered radical. Radical R1, thermally stable to about 100 K and photobleachable easily with white light, was the product of deprotonation at the amino group by the primary radical cation. Radical R2, also thermally stable to about 100 K, was the product of protonation at N3 of the primary radical anion. Radical R3, stable to about 170 K, was centered in the deoxyribose moiety and evidently was the result of net hydrogen abstraction from C4'. Radicals R4 and R5 were the C2 and C8 H-addition products with couplings typical of those species. Both R4 and R5 were formed at 10 K and were stable at room temperature. The behavior of R1 in several systems provides additional evidence for significant involvement of the hydrogen-bonding environment in controlling the stabilization (or formation) of radicals resulting directly from ionization, as described previously (Radiat. Res. 131, 272-284, 1992). From comparison of amino-group hydrogen-bonding environments in which radicals with the structure of R1 were stabilized, we conclude that oxygen atoms as proton acceptors are important in permitting the charge and spin separation necessary for radical stabilization. In particular, oxygens of ROH structures seem most efficient by readily permitting a multi-proton shuffle through a mechanism amounting to proton exchange. The collective results show that stabilization of these products is unlikely unless the charge and spin can be separated by at least one intervening molecule.

Deoxyadenosines↗