Effect of cold blood cardioplegia enriched with potassium-magnesium aspartate during coronary artery bypass grafting

AIM

The aim of this investigation is to evaluate the effect of enriched with potassium-magnesium aspartate cold-blood cardioplegia on early reperfusion injury and postoperative arrhythmias in patients with ischemic heart disease undergoing coronary artery bypass grafting (CABG), using measurements of cardiac troponin I (CTnI), hemodynamic indexes and clinical parameters.

METHODS

Forty patients with three-vessel coronary artery disease (CAD) and stable angina, receiving first-time elective CABG, were randomly divided into 2 groups: patients in control group (C group n=20) received routine institutional cold blood cardioplegia (4 degrees C) concentration of Mg2+4 mmol/L, Ca2+1.2 mmol/L and K+ 24mmol/L during myocardial arrest. Patients in P group (n=20) received modified cold blood cardioplegia enriched with potassium-magnesium aspartate and maintained concentration of Mg2+10 mmol/L, Ca2+1.2 mmol/L and K+20mmol/L in the final blood cardioplegia solution. Clinical outcomes were observed during operation and postoperatively. Serial venous blood samples for CTnI were obtained before induction, after cardiopulmonary bypass (CPB), and postoperative 6, 24, and 72 hours. Hemodynamic indexes were obtained before and after bypass by the radial catheter and Swan-Ganz catheter.

RESULTS

In both groups, there were no differences regarding preoperative parameters. There were no cardiac related deaths in either group. The time required to achieve cardioplegic arrest after cardioplegia administration was significantly shorter in P group (47.5+/-16.3 s) than in C group (62.5+/-17.6 s) (P<0.01). The number of patients showing a return to spontaneous rhythm after clamp off was significantly greater in P group (n=20, 100%) than in C group (n=14, 70%) (P<0.01). Eight patients in C group had atrial fibrillation (AF) compared with two patients in P group (P<0.05) in the early of postoperative period. The level of CTnI increased 6 hours and 12 hours postoperatively, and there was a significant difference between groups (P<0.05). P group also shortened the time of postoperative mechanical ventilation (P<0.05) after surgery.

CONCLUSIONS

Cold blood cardioplegia enriched with potassium-magnesium aspartate is beneficial on reducing reperfusion injury.

Outcome of parastomal hernia repair with and without midline laparotomy

BACKGROUND

Surgical options for parastomal hernia (PSH) repair are primary fascial, mesh repair, and relocation with or without midline laparotomy. Overall, recurrence rates are higher after fascial repairs than after relocation. However, stoma relocation may require a midline laparotomy with higher associated morbidity. The aim of this study was to assess the outcome of PSH repair with relocation with or without a midline laparotomy.

METHODS

All patients who underwent PSH repair with relocation were identified from a clinical database. Data were collected by retrospective review of medical records including patient demographics, presenting symptoms, predisposing factors, type of surgery, postoperative complications, recurrence, and follow-up. Patients were divided into two subgroups, with or without a midline laparotomy. In patients without a laparotomy, the stoma was intraperitoneally mobilized, passed behind the abdominal wall, and delivered and matured through a premarked stoma site, across the midline.

RESULTS

Between 1992 and 2001, a total of 27 patients underwent PSH repair with relocation of the stoma to the opposite side of the abdominal wall. Of these, the operation was performed without a midline laparotomy in 11 patients (41%). There were no significant differences in age, gender, body mass index, and the duration of hernia between the non-laparotomy and laparotomy groups. Prior abdominal surgery was recorded for 3 patients in the group without a laparotomy and for 9 patients in the group with a laparotomy (p=NS). Although not quantified, patients in the non-laparotomy group were less likely to have significant intraabdominal adhesions. Conversely, patients in the laparotomy group had more advanced adhesions. The operative time was longer in the group with a laparotomy than in the group without [96.8 (50-220) minutes vs. 123.9 (45-360) minutes; (p=NS)], and the mean hospital stay was significantly less in patients without vs. with a laparotomy [5.5 (SD=1.6) days vs. 9.5 (SD=3.8) days, respectively; (p<0.05)]. There was only one recurrence in the group without a laparotomy compared to 3 in the group with a laparotomy. The mean follow-up periods were 36.8 and 56.6 months in the groups without and with a laparotomy, respectively. The postoperative complications included wound infection that occurred in 3 patients in each group.

CONCLUSIONS

PSH repair with relocation without laparotomy was associated with a significantly shorter hospital stay, possibly due to the lack of a midline abdominal wound. It may not be feasible in patients with significant intraabdominal adhesions.

Unilateral optic nerve transection up-regulate Hsp70 protein expression in lateral geniculate nucleus of rats

Studies have demonstrated that optic nerve transection results in apoptotic cell death of retinal ganglion cells (RGCs) and neurons within lateral geniculate nucleus (LGN). Heat shock protein (Hsp) 70 was reported to be involved in protecting cells from injury under various pathological conditions in vivo and in vitro. To determine the involvement of Hsp70 in protecting neurons within LGN against damage or loss induced by optic nerve injuries, we observed the changes in protein expression and distribution of Hsp70 in LGN at days 1, 3, 7, 14 and 28 after unilateral optic nerve transection in the left eye of Sprague-Dawley rats by using Western blot analysis and immunohistochemical staining. We found that the levels of Hsp70 protein expression increased significantly (p < 0.05, n = 6 for each group) in both right and left LGN of rats following left optic nerve transection 1-7 days. The maximum of Hsp70 expression reached at day 3. However, Hsp70 protein expression levels in both right and left LGN returned to control levels at 14 and 28 days after left optic nerve lesion. In addition, the increased Hsp70 expression, which mainly localized in the intergeniculate leaflet of LGN, was also observed by immunostaining in right LGN at the end of day 3 after the lesion. These results suggest that increased expression of Hsp70 may be involved in protecting neurons within LGN against damage or loss induced by left optic nerve transection at early stage.

Effect of stealthy liposomal topotecan plus amlodipine on the multidrug-resistant leukaemia cells in vitro and xenograft in mice

BACKGROUND

Multidrug resistance (MDR) is a major obstacle to successful cancer chemotherapy as the over-expressed MDR protein acts as an efflux pump, which leads to a reduction in the uptake of the anticancer agent by tumour cells. We combined topotecan and amlodipine together into the stealthy liposomes, in which amlodipine was applied as a MDR reversing agent to overcome the resistance.

MATERIALS AND METHODS

Cytotoxicity, apoptosis and the signalling pathway assays were performed on human chronic myelogenous leukaemia K562, promyelocytic leukaemia HL-60 and MDR HL-60 cells, respectively. Pharmacokinetics and antitumour activity studies were performed on normal Kunming mice and female BALB/c nude mice with MDR HL-60 xenografts, respectively.

RESULTS

Topotecan alone was effective in inhibiting the growth of non-resistant leukaemia cells, K562 and HL-60 cells but not the growth of MDR HL-60 cells. The resistance of topotecan in MDR HL-60 cells was potently reversed by the addition of amlodipine. Moreover, amlodipine enhanced the apoptosis-inducing effect of topotecan synergistically. Apoptosis was through activating caspases in a cascade: first, the initiator caspase 8 and then effectors caspase 3/7 (total activity of caspases 3 and 7) were activated. Being encapsulated into the stealthy liposomes with an acidic internal medium, topotecan existed dominantly in an active lactone species, which was reversibly changed from an inactive carboxylate form via a pH-dependent reaction. After administration of stealthy liposomes to mice, the blood exposure of the lactone form was evidently increased and extended. The antitumour effects in the MDR HL-60 xenografted tumour were stealthy liposomal topotecan (SLT) plus amlodipine > SLT > un-encapsulated topotecan > blank control.

CONCLUSIONS

The enhanced antitumour activity in the MDR HL-60 cells by the SLT plus amlodipine could be owing to multiple reasons: (a) synergistic apoptosis inducing effect, (b) reversing MDR by amlodipine and (c) increasing the availability of active lactone of topotecan by the stealthy liposomes. The apoptosis induced by amlodipine is through caspase 8 and then the 3/7 signalling pathway.

Variable precision registration via wavelets: optimal spatial scales for inter-subject registration of functional MRI

The detection of significantly activated brain regions in multi-subject functional magnetic resonance imaging (fMRI) studies almost invariably entails the coregistration of individual subjects' data in a standard space. Here, we investigate how sensitivity to detect loci of generic activation in such studies may be conditioned by the precision of anatomical registration. We describe a novel algorithm, implemented in the wavelet domain, for inhomogeneous deformation of individual images to match a template. The algorithm matches anatomical features in a coarse-to-fine fashion, first minimising a cost function in terms of relatively coarse spatial features and then proceeding iteratively to match the images in terms of progressively more detailed anatomical features. Applying the method to data acquired from two groups of 12 healthy volunteers (with mean age 27 and 70 years, respectively), during performance of a paired associate learning task, we show that geometrical overlap between template and individual images is monotonically improved, compared to an affine transform, by additional inhomogeneous deformations informed by more detailed features. Likewise, sensitivity to detect activated voxels can be substantially improved, by a factor of 4 or more, if wavelet-mediated deformations informed by medium-sized anatomical features are applied in addition to a preliminary affine transform. However, sensitivity to detect activated voxels was reduced by "over-registering" data or matching anatomical features at the finest scales of the wavelet transform. The benefits of variable precision registration are particularly salient for data acquired in older subjects, which showed evidence of greater inter-subject anatomic variability and generally required more extensive local deformation to achieve a satisfactory match to the template image. We conclude that major benefits in sensitivity to detect functional activation in multi-subject fMRI studies can be attained with an inhomogeneous deformation applied over appropriate spatial scales.

Decreased phosphorylation and protein expression of ERK1/2 in the brain of hypoxic preconditioned mice

Accumulated reports have suggested that activation of protein kinase C (PKC) isoforms may involve the activation of extracellular signal-regulated kinases 1/2 (ERK1/2) in the neuronal response to hypoxic stimuli. We have previously demonstrated that the membrane translocation or activation of conventional PKC (cPKC) betaII, gamma and novel PKC (nPKC) epsilon are increased in the early phase of cerebral hypoxic preconditioning in mice. However, the role of ERK1/2 in the development of cerebral hypoxic preconditioning is unclear. In the current study, we used Western blot analysis to investigate the effects of repetitive hypoxic exposure (H0-H6, n=6 for each group) on the levels of phosphorylation and protein expression of ERK1/2 in the frontal cortex and the whole hippocampus of mice. We found that the levels of phosphorylated ERK1/2, not protein expression of ERK1/2, decreased significantly in both cortex and hippocampus of the early hypoxic preconditioned mice (H1-H4), when compared to that of the normoxic group (p<0.05). In addition, a significant decrease (p<0.05) in the ERK1/2 protein expression, not the phosphorylated form of ERK1/2, was found both in the frontal cortex and hippocampus of mice followed hypoxia with previous hypoxia (H5 and H6). These results suggest that the decreased phosphorylation and downregulation of protein expression of ERK1/2 might be involved in the development of hypoxic preconditioning.

170 POST-THAW VIABILITY OF IN VITRO-PRODUCED BOVINE EMBRYOS CULTURED EITHER IN HOST CAPRINE REPRODUCTIVE TRACTS OR IN VITRO

In vitro culture of bovine embryos is usually associated with poor pregnancy rate following cryopreservation. The objective of this study was to compare the post-thaw viability of in vitro-produced bovine zygotes, cultured in vitro or in the reproductive tract of a host goat. Cumulus-oocyte complexes were matured in vitro, and in vitro fertilization was carried out with frozen-thawed semen as per standard laboratory procedures. At 18-20 h post-fertilization, zygotes were stripped of remaining cumulus cells and randomly separated into culture treatments. In three replicates, a total of 606 embryos were surgically transferred 12 to 24 h post-ovulation to the oviducts of an estrous-synchronized goat (VIVO) and 550 embryos were cultured in G1.3 for 72 h and then moved to G2.3 medium for 96 h and in a humidified atmosphere of 5% CO2, 5% O2, and 90% N2 (IVC). On Day 7, embryos were flushed from the excised tract with a 69.5% recovery rate or removed from culture. Embryos were classified according to IETS criteria with grades and stages recorded. All data were analyzed using the one-way analysis of variance and means were compared using Student's t-test. No differences were seen in the percentage of freezable quality embryos per total recovered between the two groups (34.3% vs. 32.3% for IVC and VIVO, respectively). However, there was a significant difference in the pre-freezing stage between the two culture groups (Stage 5.5 � 0.22 vs. Stage 4.8 � 0.26 for IVC and VIVO, respectively; P < 0.05), but no difference in the quality grade. All embryos greater than Stage 4, Grade 2 were frozen in groups of 5-10 in ethylene glycol with sucrose (Vigro Ethylene Glycol Freeze Plus; Bioniche Animal Health, Belleville, Ontario, Canada) in 0.25-mL straws. After thawing, embryo groups were washed, rehydrated, and incubated in G2.3 as above. Morphology was assessed by assigning grade and stage objectively at 24 h and 48 h post-thaw. Post-thaw viability in vitro was not different between groups (73.4% vs. 72.7% for IVC and VIVO, respectively). The average changes in morphology post-thaw from pre-freezing to 24 h and from 24 h to 48 h within each freezing group were determined. There was no significant difference in the mean change in stage (0.67 � 0.15 vs. 0.82 � 0.17 at 24 h and 0.31 � 0.09 vs. 0.37 � 0.10 at 48 h for IVC and VIVO, respectively) or grade (0.60 � 0.15 vs. 0.41 � 0.17 at 24 h and 0.03 � 0.06 vs. 0.14 � 0.07 at 48 h for IVC and VIVO, respectively) at either observation point. These results suggest that culture of in vitro-fertilized bovine embryos in the caprine reproductive tract did not alter post-thaw development or improve post thaw viability compared to in vitro cultured controls. However, morphological evaluation is too subjective to successfully predict pregnancy rate after transfer; therefore, further study is needed to determine if there are differences in pregnancy rates between these culture methods.

187 RE-ESTABLISHMENT OF AN EXTINCT STRAIN OF SHEEP FROM A LIMITED SUPPLY OF FROZEN SEMEN

The objective of this study was to restore a line of sheep that exhibits spontaneous X-linked factor VIII deficiency closely mimicking human hemophilia A. Six straws of frozen semen from an affected Alpine White male were obtained from Switzerland. In the first experiment the straw of semen thawed was of poor quality. Two ewes were synchronized for use as embryo donors (MOET) by means of CIDRs for 14 days and superovulated with declining doses of FSH (184 mg) twice daily for 3 days. PMSG (200 IU) was given with the final dose of FSH and 1000 IU of hCG 12 h post-CIDR removal. The ewes were surgically inseminated 24 h later. Oviducts were flushed 48 h post-insemination producing 13 unfertilized ova (UFO). Spermatozoa were used for intracytoplasmic sperm injection (ICSI) utilizing oocytes collected from superstimulated ewes by laporatomy. These ewes were synchronized with CIDRs (15 days) and superovulated with a declining dose of FSH (204 mg) twice daily for 3.5 days. Utilizing 236 oocytes, ICSI produced 189 embryos, an 80% embryo/oocyte rate. Embryos were transferred surgically to the oviducts of 17 synchronized recipients. Recipients were synchronized using sponges (Ovakron; Heriot Agvet, Rowville, Victoria, Australia) containing 30 mg of flugestone acetate (14 days) and given PMSG (400 IU) at sponge removal, followed by 1000 IU of hCG 12 h post-sponge removal. Eleven recipients produced 17 lambs for a lamb/embryo rate of 8.9%. The straw of semen utilized for the second experiment was of higher quality. Three ewes were superstimulated for use as MOET donors, as above, with increased doses of FSH (228 mg) and PMSG (500 IU). Donors were surgically inseminated and oviductal flushes were performed 40 h post-insemination, yielding 19 UFO and 12 embryos for an embryo/oocyte rate of 38.7%. Embryos were transferred to four recipients, synchronized as above with an increased dose of PMSG (600 IU). These MOET recipients produced nine lambs for a lamb/embryo rate of 75%. Semen was used to produce embryos via in vitro fertilization (IVF) using oocytes collected from superstimulated ewes (as above with an increase of FSH to 252 mg). IVF produced 91 embryos from 247 oocytes for an embryo/oocyte rate of 36.8%. Embryos were transferred to 20 recipients 24 to 48 h post-fertilization. Seven recipients maintained pregnancy and produced 10 lambs with a lamb/embryo rate of 11%. ICSI was also utilized, producing 54 embryos from 98 oocytes, an embryo/oocyte rate of 55.1%. Embryos were transferred to eight recipients; none maintained pregnancy. Through the use of multiple reproductive technologies, 36 lambs (22 carriers) were produced from two straws of semen. Carriers will be bred back to their sire in a similar program to produce affected lambs. The authors would like to acknowledge J. Liu and M. Ridha for their contributions. This work was supported by NIH Grant HL073737-12.

326 EVALUATION OF CULTURE DURATION AND PARTIAL CUMULUS CELL REMOVAL DURING CANINE OOCYTE MATURATION

The objectives of this study were to determine whether the percentage of canine oocytes that resume meiosis during in vitro maturation could be increased by either increasing culture duration or by removing approximately one-half of the cumulus cells 24 h after oocytes were placed into culture. Canine female reproductive tracts were collected from a local clinic and ovaries were minced in warm TL-HEPES. Oocytes with a consistently dark ooplasm and at least two layers of cumulus cells were selected, cultured in a basic canine oocyte in vitro maturation medium consisting of TCM-199 with Earl's salts, 2.92 mM Ca-lactate, 20 mM pyruvic acid, 4.43 mM HEPES, 10% fetal calf serum, 1% Penicillin/Streptomycin (GibcoBRL, Grand Island, NY, USA), and 5 μg/mL porcine somatotropin, and incubated at 38.5°C in 5% CO2 in humidified air. Treatment groups were randomly assigned and oocytes were cultured for 60, 84, or 132 h (Basic). From each of these groups, one-half of the oocytes were pipetted through a fine bore pipette to partially remove the cumulus cells 24 h after the start of culture (Basic–1/2). At the end of culture, all oocytes were denuded and the nuclear status was observed with Hoechst 33342 under ultraviolet fluorescence. All data were analyzed by ANOVA with P < 0.05. Since the canine oocyte is ovulated at the germinal vesicle (GV) stage of meiosis and requires up to five days to mature in the oviduct, it was hypothesized that an increased culture time would allow for more oocytes to undergo nuclear maturation to metaphase II (MII). It was also hypothesized that partial removal of cumulus cells would decrease the cumulus cell component in the ooplasm that sustains meiotic arrest, allowing for more oocytes to resume meiosis (RM = germinal vesicle breakdown to MII). Results within each treatment group indicate that there is no significant difference between culture duration and the percent of oocytes that mature to MII. Additionally, there was no significance in the percent of oocytes that resumed meiosis after partial cumulus cell removal. Taken together, these data suggest that neither treatment is effective in canine in vitro maturation systems, given the current maturation culture conditions. Table 1. Nuclear status* of oocytes for three time periods with or without partial cumulus cell removal