Interspecies implantation and mitochondria fate of panda-rabbit cloned embryos.
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Somatic cell nuclei of giant pandas can dedifferentiate in enucleated rabbit ooplasm, and the reconstructed eggs can develop to blastocysts. In order to observe whether these interspecies cloned embryos can implant in the uterus of an animal other than the panda, we transferred approximately 2300 panda-rabbit cloned embryos into 100 synchronized rabbit recipients, and none became pregnant. In another approach, we cotransferred both panda-rabbit and cat-rabbit interspecies cloned embryos into the oviducts of 21 cat recipients. Fourteen recipients exhibited estrus within 35 days; five recipients exhibited estrus 43-48 days after embryo transfer; and the other two recipients died of pneumonia, one of which was found to be pregnant with six early fetuses when an autopsy was performed. Microsatellite DNA analysis of these early fetuses confirmed that two were from giant panda-rabbit cloned embryos. The results demonstrated that panda-rabbit cloned embryos can implant in the uterus of a third species, the domestic cat. By using mitochondrial-specific probes of panda and rabbit, we found that mitochondria from both panda somatic cells and rabbit ooplasm coexisted in early blastocysts, but mitochondria from rabbit ooplasm decreased, and those from panda donor cells dominated in early fetuses after implantation. Our results reveal that mitochondria from donor cells may substitute those from recipient oocytes in postimplanted, interspecies cloned embryos. (+info)
17 beta-estradiol attenuates intimal hyperplasia and macrophage accumulation with a reduction in monocyte chemoattractant protein 1 expression in a vein graft model.
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OBJECTIVE: Autogenous vein grafts are commonly used for arterial reconstructive procedures. Their success is limited by the development of intimal hyperplasia, a fibroproliferative disease that predisposes the grafts to occlusive stenosis. Our goal was to assess whether 17 beta-estradiol (E(2)) inhibits vein graft intimal hyperplasia coincident with a reduction in monocyte chemoattractant protein 1 (MCP-1) expression and macrophage accumulation. METHOD: Male Lewis rats were implanted with time-release pellets that contained 0.5 mg E(2) (E5 group) or placebo (PL group). Epigastric vein to common femoral artery interposition grafts were harvested at 2, 4, 8, and 12 weeks after surgery. We assessed macrophage/monocytes numbers, proliferating cell nuclear antigen, MCP-1, and transforming growth factor-beta1 with use of immunohistochemistry. MCP-1 message expression was quantified by real-time polymerase chain reaction. RESULTS: The time-release pellets raised the serum E(2) level to greater than 250 pg/mL on the day of surgery. Serum E(2) level declined to 43 +/- 13 pg/mL by 4 weeks and to baseline by 6 weeks. We found that the neointimal area ratio was reduced significantly in the E5 group at 2 and 4 weeks (45%, P <.05, and 68%, P < 0.05, respectively) relative to that in the PL group. The number of proliferating cells was reduced in the E5 group. There was a significant attenuation of MCP-1 expression and of the number of macrophages accumulating in the graft with E(2) treatment. Furthermore, MCP-1 messenger ribonucleic acid expression was also significantly attenuated in the E5 group at 4 weeks when compared to the PL group. There was no significant difference between the two groups in the expression of transforming growth factor-beta1. CONCLUSIONS: E(2) treatment reduces vein-graft intimal hyperplasia coincident with a reduction in MCP-1 expression, macrophage accumulation, and cell proliferation. (+info)
Metabolite diffusion in giant muscle fibers of the spiny lobster Panulirus argus.
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The time- and orientation-dependence of metabolite diffusion in giant muscle fibers of the lobster Panulirus argus was examined using (31)P- and (1)H-pulsed-field gradient nuclear magnetic resonance. The (31)P resonance for arginine phosphate and the (1)H resonances for betaine, arginine/arginine phosphate and -CH(2)/-CH groups were suitable for measurement of the apparent diffusion coefficient, D. Diffusion was measured axially, D(//), and radially, D( perpendicular ), in fibers over diffusion times of 20 to 300 ms. Diffusion was strongly anisotropic, and D(//) was higher than D( perpendicular ) at all times. Radial diffusion decreased with time until a steady-state value was reached at a diffusion time of approximately 100 ms. Changes in D( perpendicular ) occurred over a time scale that was consistent with previous measurements from fish and mammalian muscle, indicating that diffusion is hindered by the same types of barriers in these diverse muscle types. The time dependence indicated that the sarcoplasmic reticulum is the principal intracellular structure that inhibits mobility in an orientation-dependent manner in skeletal muscle. The abdominal muscles in P. argus are used for anaerobic, burst contractions during an escape maneuver. The fact that these muscle fibers have diameters that may exceed hundreds of microns in diameter, and nearly all of the mitochondria are localized near the sarcolemmal membrane, suggests that barriers that hinder radial diffusion of ATP equivalents may ultimately limit the rate of post-contractile recovery. (+info)
Complications of laparoscopy.
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Five years' experience with the laparoscope raises doubts about its continued use for sterilization. As a diagnostic tool, however, it serves a useful function. (+info)
Vascular protection by estrogen in ischemia-reperfusion injury requires endothelial nitric oxide synthase.
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Estrogen increases nitric oxide (NO) production by inducing the activity of endothelial NO synthase (eNOS) (Simoncini et al. Nature 407: 538, 2000). Ischemia (30 min) and reperfusion (I/R) increased the number of adherent leukocytes and decreased their rolling velocities in mouse cremaster muscle venules with a strong dependence on wall shear rate. Minimum rolling velocity at approximately 5 min after the onset of reperfusion was accompanied by increased P-selectin expression. This preceded the peak in leukocyte adhesion (at 10-15 min). In untreated wild-type mice, I/R caused a decrease of leukocyte rolling velocity from 37 to 26 microm/s and a 2.0-fold increase in leukocyte adhesion. Both were completely abolished by 0.25 mg ip estrogen 1 h before surgery. In eNOS(-/-) mice, the decrease of leukocyte rolling velocity and increase in adhesion were similar but were only marginally improved by estrogen. We conclude that the protective effect of estrogen, as measured by leukocyte rolling and adhesion, is significantly reduced in eNOS(-/-) mice, suggesting that induction of eNOS activity is the major mechanism of vasoprotection by estrogen in this model. (+info)
Studies on human adipose cells in culture: relation of cell size and multiplication to donor age.
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In an effort to test the adipose hyperplasia theory of obesity in humans, adipose cells, derived from anterior abdominal walls of human infants and children, were grown in synthetic medium (McCoy's 5A Medium) supplemented with 20% fetal calf serum. Adipose cells which became delipidinized in culture were found to be capable of division and the rate and number of cell divisions was age dependent. Cells of infants under 1 yr of age and cells derived from early adolescent children divided to varying degrees in culture. Adipose cells from children aged 1-10 yr showed no cell division. Cell division was never observed in a lipid-laden adipocyte. Measurements of cell diameter showed that after the first year of life, cell size increased progressively with age. During the first year adipose cell size appeared to reflect the rapid hyperplasia of the first 3 mo, reaching smallest size at 3-12 mo but increasing thereafter. (+info)
The use of Mersilene mesh in repair of abdominal wall hernias: a clinical and experimental study.
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Use of synthetic materials in herniplasty has been a controversial issue. In order to determine the influence of Mersilene mesh on the strength of healing abdominal wounds and its effectiveness in repair of hernia, experimental and clinical studies were undertaken. Experimental study included 175 male rats divided into three groups subjected to either: 1) an incision made only through the skin and closed with 3-0 silk sutures; 2) a 2.5 cm midline incision through the musculature and peritoneum closed with 2-0 Mersilene suture; or 3) the same procedure as group 2 with the addition of a Mersilene mesh onlay graft. Bursting strength of abdominal wounds as determined in all groups at intervals. Wounds of the group treated with the mesh exhibited significantly greater (P less than 0.01) bursting strength. Clinical trial consisted of 100 consecutive adult patients in which an onlay graft of Mersilene mesh was used in the hernioplasty. Mesh was used as an adjunct in patients with: 1) large ventral hernias; 2) direct hernias resulting from severely attenuated transversialis fascia; 3) indirect hernias associated with a large internal ring and a weak posterior inguinal wall; or 4) combined direct and indirect hernias. All were followed for a minimum of one year to determine the incidence of complication and rate of recurrence. This study suggests that: 1) Mersilene mesh increases the strength of healing abdominal wounds in rats; and 2) repair of large hernias with Mersilene mesh results in an acceptable morbidity and a lowered rate of recurrence. (+info)
Opioid-resistant respiratory pathway from the preinspiratory neurones to abdominal muscles: in vivo and in vitro study in the newborn rat.
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We report that after spontaneous breathing movements are stopped by administration of opioids (opioid-induced apnoea) in neonatal rats, abdominal muscles continue to contract at a rate similar to that observed during periods of ventilation. Correspondingly, in vitro bath application of a mu opioid receptor agonist suppresses the activity of the fourth cervical root (C4) supplying the diaphragm, but not the rhythmic activity of the first lumbar root (L1) innervating the abdominal muscles. This indicates the existence of opioid-resistant rhythmogenic neurones and a neuronal pathway transmitting their activity to the abdominal motoneurones. We have investigated this pathway by using a brainstem-spinal cord preparation of the neonatal rat. We identified bulbospinal neurones with a firing pattern identical to that of the L1 root. These neurones were located caudal to the obex in the vicinity of the nucleus retroambiguus. Resting potentials ranged from -49 to -40 mV (mean +/- S.D. -44.0 +/- 4.3 mV). The mean input resistance was 315.5 +/- 54.8 MOmega. The mean antidromic latency from the L1 level was 42.8 +/- 4.4 ms. Axons crossed the midline at the level of the cell body. The activity pattern of the bulbospinal neurones and the L1 root consisted of two bursts per respiratory cycle with a silent period during inspiration. This pattern is characteristic of preinspiratory neurones. We found that 11 % of the preinspiratory neurones projected to the area where the bulbospinal neurones were located. These preinspiratory neurones were found in the rostral ventrolateral medulla close (200-350 microm) to the ventral surface at the level of the rostral half of the nucleus retrofacialis. Our data suggest the operation of a disynaptic pathway from the preinspiratory neurones to the L1 motoneurones in the in vitro preparation. We propose that the same pathway is responsible for rhythmic activation of the abdominal muscles during opioid-induced apnoea in the newborn rat. (+info)