Perforator flaps are perfused through a long vessel whose calibre decreases from its origin to the skin, because all branches have been sealed, resulting in a conduit with resistances in series, rather than a tree with resistances in parallel, as in the normal systemic circulation. This study was planned to assess whether the differences between perforator flap and normal systemic vasculature have an impact on haemodynamic parameters in perforator flaps and on their clinical significance. The study was performed on 10 patients. Echo-colour-Doppler measurement of diameters, velocity of flow and calculations of flow rate were made at the level of flap pedicle artery and skin perforator artery, pre- and post-operatively in each patient. Statistical analysis used the Wilcoxon matched pairs signed sum rank test. Our data show that in the donor area pre-operatively, blood velocity in skin artery perforator is lower that in the corresponding pedicle artery, whereas post-operatively, in perforator flaps, blood velocity in the perforator is higher than in the pedicle. The difference was statistically significant (P<0.01). There is an inversion of the gradient of blood velocity between pedicle artery and perforator artery compared to normal circulation. Furthermore, in normal circulation flow through the perforator was found smaller than that at the pedicle, whereas in perforator flaps, flow through the perforator is smaller but is a greater proportion of the flow through the pedicle and the difference is statistically significant (P<0.01). Therefore, the velocity of blood and the rate of flow reaching the skin are higher in perforator flaps than in normal circulation. 相似文献
Background: The study hypothesizes that nitrous oxide (N2O) releases opioid peptide in the brain stem, which results in inhibition of [gamma]-aminobutyric acid-mediated (GABAergic) neurons that tonically inhibit the descending noradrenergic inhibitory neurons (DNIN), resulting in activation of DNIN. In the spinal cord, activation of DNIN leads to the release of norepinephrine, which inhibits nociceptive processing through direct activation of [alpha]2 adrenoceptor and indirect activation of GABAergic neurons through [alpha]1 adrenoceptor. Arising from this hypothesis, it follows that GABAergic neurons will modulate the antinociceptive effect of N2O in diametrically opposite directions at supraspinal and spinal levels. The authors have tested this tenet and further examined the effect of midazolam, a GABA-mimetic agent, on N2O-induced antinociceptive effect.
Methods: Adult male Fischer rats were administered muscimol (GABAA receptor agonist) intracerebroventricularly (icv), gabazine (GABAA receptor antagonist) intrathecally (intrathecal), or midazolam intraperitoneally (intraperitoneal). Fifteen minutes later, they were exposed to air or 75% N2O and were subjected to the plantar test after 30 min of gas exposure. In some animals administered with midazolam, gas exposure was continued for 90 min, and the brain and spinal cord were examined immunohistochemically.
Results: The N2O-induced antinociceptive effect, which was attenuated by icv muscimol, intrathecal gabazine, and intraperitoneal midazolam. Midazolam inhibited N2O-induced c-Fos expression (a marker of neuronal activation) in the pontine A7 and spinal cord. 相似文献
Summary. The complete genomic sequence of galinsoga mosaic virus (GaMV) was determined. The genome consists of 3 803 nucleotides and
has five open reading frames (ORFs). The 5′ ORF (ORF 1) encodes a protein with predicted molecular mass of 23 kDa and readthrough
of its amber stop codon probably yields a 82 kDa protein (ORF 2). ORFs 3 and 4 encode two polypeptides with molecular masses
of 8 and 7 kDa, respectively. ORF 5 encodes the 36 kDa capsid protein. Amino acid sequence comparisons revealed that the nonstructural
proteins encoded by ORFs 1, 3, and 4 were more similar to the corresponding gene products of tobacco necrosis virus, strain
A, than to those of carmoviruses. Conversely, the coat protein was more similar to that of tombusviruses. The readthrough
region of the viral replicase (ORF 2) had high sequence homology with that of carmo-, tombus-, and necroviruses. Computer
analysis of the protein encoded by ORF 1 as well as of the corresponding product of turnip crinkle (TCV) and melon necrotic
spot (MNSV) carmoviruses revealed the presence of a sequence with local hydrophobicity and hydrophobic moment characteristic
of mitochondrial targeting sequence which may explain the origin of the carmovirus-induced multivesicular bodies from mitochondria.
Accepted August 25, 1997 Received June 18, 1997 相似文献
It is well known that nipples reconstructed using local tissue flaps slowly flatten. Furthermore, patients with implant reconstruction show the highest amount of nipple projection loss. This article describes some modifications to the technique proposed by Thomas et al in order to maintain flap projection. We undertook a prospective study to evaluate the effectiveness of our technique, named 'arrow flap'. We compared a series of patients with unilateral breast reconstruction (16 implants, 16 TRAM flaps) who underwent nipple reconstruction using either the 'modified star flap' or the 'arrow flap'. The statistical significance of the results was determined by Student's t test. The arrow flap proved to have a higher residual projection and these results were statistically significant. Furthermore, it has been equally useful on implant and autologous reconstructions. This technique is easy to learn and to perform. The procedure is reliable and patient satisfaction and compliance are very good. 相似文献
1. The direct vascular effects of adenosine and ATP were compared in the isolated and perfused mesenteric arterial bed of the rat. The actions of analogues of adenosine and ATP were also examined. 2. In preparations at basal tone, adenosine lacked vasoconstrictor actions, while ATP elicited dose-dependent vasoconstrictor responses. When the tone of preparations was raised by adding methoxamine to the perfusate, adenosine and its stable analogue, 2-chloroadenosine (2-CADO) elicited dose-dependent vasodilation. The A2 adenosine receptor agonist, 5'-N-ethylcarboxamidoadenosine (NECA) was active at lower doses than adenosine, while the A2a-selective agonist, CGS 21680 and the selective A1 agonist, N6-cyclopentyladenosine (CPA) failed to induce vasodilatation. ATP and its analogue, 2-methylthio ATP, elicited dose-dependent vasodilatation at doses 400 fold lower than adenosine. 3. Vasodilator responses to adenosine and 2-CADO were sensitive to antagonism by 1 microM 8-sulphophenyltheophylline (8-SPT) and were unaffected by inhibition of nitric oxide synthase by N omega-nitro-L-arginine methyl ester (L-NAME). In contrast, vasodilator responses to ATP were not sensitive to antagonism by 8-SPT and were almost abolished by L-NAME treatment. 4. These results indicate that in the rat mesenteric arterial bed, while both adenosine and ATP participate in the purinergic control of vascular tone, adenosine appears to be a weaker vasodilator than ATP and lacks vasoconstrictor action. A2b adenosine receptors account for the adenosine-induced vasodilatation which is independent of the production of nitric oxide. 相似文献
The authors compare three methodologies based on the immunology (RIA, FPIA, LIA) in the determination of two important parameters of the so-called thyroid outline: triiodothyronine (T-3) and thyroxine (T-4). The correlations between the analytic systems examined are presented and discussed. 相似文献
Nowadays, microsurgery performed for oral reconstruction of cancer patients, has become the standard treatment in restoring oral functions. The free radial forearm flap (FRFF) is still apparently the first reconstructive choice in oral cavity cancers. Recently the anterolateral thigh flap (ALTF) seemed to challenge the superiority of FRFF. The lack of functional data on which to base this recent supposition is the reason for this new research. Twenty reconstructed patients were enrolled for this study. Speech, swallowing, and donor site complications were studied to assess differences between the two techniques. Results show that difference in function between ALTF and FRFF groups is statistically insignificant. Donor site risks and complications seem to be the only variables among groups. These variables may be used as indicators when making a surgical choice. 相似文献
The solubilities in water of a number of sodium salts of weakly acidic drugs were determined. The compounds examined included barbiturates, sulfonamides, and hydantoins. When the logarithm of the aqueous solubilities of the salts were plotted against their melting points, an inverse relationship was observed; however, a good correlation was not immediately apparent. Further studies were conducted on the solid phases of the drugs after equilibration with water, using calorimetric, spectrophotometric, and gravimetric methods. In many cases, hydrate formation was evident and, for some compounds, the stoichiometric amount of water in the crystal was different before and after equilibration with water. Multivariate analysis of the data indicated that the logarithms of the molar solubilities were inversely related to both the melting points and the stoichiometric amounts of water in the crystal hydrates, but were unrelated to the polarity of the corresponding acid forms of the drugs. Therefore, for the sodium salts of these drugs, the solubility is primarily controlled by the properties of the solid phase which exists in equilibrium with the solution phase. 相似文献