Search PubMed⌕ Search

Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 487 records · Page 27Linked to original sources
PubMed1996

Prostatic ductal system in rats: regional variation in stromal organization.

The rat prostate is composed of a complex system of branching ducts which terminate proximally at the urethra. It has been recognized that epithelial cells lining the ducts respond differently to androgen in various regions of the ducts, with responses ranging from proliferation to apoptosis, but the cellular mechanisms underlying these effects are unclear. Interaction between prostatic stroma and epithelium is essential to normal prostate growth and development, and the prostatic stroma is thought to be the first site of androgen action. Therefore we have examined the organization and distribution of stromal cell types along the rat prostatic ductal system. Using immunohistochemical techniques, we observed abundant fibrous tissue surrounding the distal region of the ducts, with a sparse, discontinuous smooth muscle layer. The intermediate region was surrounded by a continuous layers of smooth muscle one to two cells thick, which increased to greater than four layers thick at the proximal region. Fibrous tissue was located in interductal spaces and occasionally interspersed within the muscle layers in both regions. These observations indicate that regional variations in the distribution of stromal cell types exist and suggest that their corresponding secretory products could be responsible for the various effects of androgen on the epithelium in the rat prostatic ductal system.

Actins↗
PubMed1996

Stromal cells of the human prostate: initial isolation and characterization.

The present study was conducted to isolate and to characterize stromal cells from the human prostate and to study the effects of androgen and different growth factors in this model system. Benign prostatic hyperplasia (BPH) tissue samples were obtained from transurethral resection of the prostate (TURP). Tissue specimens were mechanically and enzymatically dissociated by treatment with DNAse and collagenase. Epithelial cells were separated from stromal cells by discontinuous Percoll gradient centrifugation. The stromal cells obtained were cultured in phenol red-free RPMI-1640 supplemented with 10% fetal bovine serum. Immunocytochemical analysis revealed that the stromal cell cultures were composed of both smooth muscle cells and fibroblasts. The short and broad, smooth muscle cells wee identified by using an antibody directed against alpha-smooth muscle actin. The thin and elongated fibroblasts stained positively for prolyl 4-hydroxylase. Smooth muscle cells were the predominant cell type in the present investigation. Typical cultures contained up to 99% of cells staining positively for alpha-smooth muscle actin. The prostate smooth muscle cultures were treated with dihydrotestosterone (DHT), bovine pituitary extract (BPE), basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta). When cells were cultured in serum free RPMI-1640 supplemented with ITS+ (insulin, transferrin, and selenious acid) no significant (P > 0.05) mitogenic effect in medium supplemented with ITS+. In the presence of 10% charcoal-stripped fetal bovine serum (cFBS) DHT, at a concentration of 0.1 nM, was able to cause a slight but significant (P < 0.05) mitogenic effect on BPH smooth muscle cells growth. Basic FGF was able to stimulate BPH smooth muscle cells in a concentration-dependent fashion. The combination of DHT and 0.1 ng/ml bFGF was able to increase the proliferation of prostate smooth muscle cells above either agents alone. Addition of BPE to serum free RPMI-1640 caused a significant (P < 0.05) stimulation of cell proliferation in a concentration-dependent fashion. Addition to TGF-beta to serum or BPE containing RPMI-1640 caused a significant (P < 0.05) inhibition to cell proliferation in a concentration-dependent fashion. TGF-beta was cytostatic to the benign prostatic smooth muscle cells only in the presence of media containing growth stimulating factors found in charcoal-stripped serum or in bovine pituitary extract. These results demonstrated that stromal fraction isolated from BPH specimens was composed of both fibroblasts and smooth muscle cells. These cells could be cultured and were able to respond to various growth stimulatory and inhibitory agents.

Cell Division↗
PubMed1996

Extent of sperm chromatin hydration determined by atomic force microscopy.

Volume measurements were performed on intact bull and mouse sperm heads and amembranous sperm nuclei, both in the fully hydrated (fluid cell) and dehydrated (air-dried on glass coverslips) states by atomic force microscopy (AFM). Data were obtained by analyzing a small population of cells/nuclei, as well as by performing repeated measurements on single cells imaged following the addition of increasing concentrations of propanol. Results show that the volume of fully hydrated, intact sperm heads and amembranous sperm chromatin particles are at least twice the volume of their air-dried counterparts. Dehydration occurs rapidly in air, and the reduction in volume of chromatin induced by water loss appears to be completely reversible. These studies demonstrate that both mouse and bull sperm chromatin are extensively hydrated in the native state, and are not as compact as previous studies have suggested.

1-Propanol↗
PubMed1996

Learning-disabled readers' working memory as a function of processing demands.

The purpose of this study was to investigate whether limitations in the enhancement of learning-disabled readers' working memory performance are attributable to process or storage functions. For Experiment 1, performance of reading-disabled, chronological age-matched, and reading level-matched children was compared on verbal and visual-spatial working memory measures under initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The results indicated that (a) learning-disabled readers' working memory performance was comparable on visual-spatial measures, but inferior to CA-matched children on verbal working memory measures; (b) learning-disabled readers' performance was superior to reading-matched counterparts across working memory conditions; and (c) performance differences remained between learning-disabled and CA-matched children or gain and maintenance conditions, even when initial and processing efficiency (probe) scores were partialed out in the analyses. Experiment 2 included the same conditions as Experiment 1, except that verbal short-term memory scores were also partialed out in the analysis. The results indicated that learning-disabled readers are inferior on both verbal and visual-spatial working memory measures when compared to CA-matched children on high demand conditions (maintenance). Two findings that emerged across experiments were (a) intercorrelations among diverse WM measures increased on demanding conditions and (b) verbal WM was not directly related to reading skill. In sum, the results support the notion that learning-disabled readers' poor working memory performance on demanding conditions reflect constraints in a central executive storage system.

Child↗
PubMed1996

Conservation of a 31-bp bovine subrepeat in centromeric satellite DNA monomers of Cervus elaphus and other cervid species.

A centromeric satellite DNA clone was isolated from the genome of the European red deer (Cervus elaphus hippelaphus) and designated Ce-Pst1. This clone was localized to the centromeric region of all red deer chromosomes with the exception of a single pair of metacentric autosomes and the Y chromosome. DNA sequence analysis of the 806-bp Ce-Pst1 clone showed 73.0-78.9% sequence homology to four previously isolated cervid centromeric satellite DNA clones, suggesting that the Ce-Pst1 clone is yet another member of the major cervid centromeric satellite DNA family. Using a DNA sequence comparison system, internal 31-bp tandem subrepeats were found in the Ce-Pst1 clone as well as in the other previously reported cervid centromeric satellite DNA monomer sequences. A 31-bp consensus sequence was constructed for each cervid monomer clone and shown to be highly homologous to the 31-bp subrepeat consensus sequence found in bovine 1.715 centromeric satellite DNA. The identification of internal subrepeats in the satellite monomers studied could suggest that amplification of an ancestral 31-bp DNA sequence may have contributed to the genesis of major cervid centromeric satellite DNA. The homology between the 31-bp subrepeats found in cervid and bovid centromeric satellite DNAs substantiates the theory that amplification of this 31-bp DNA sequence may have occurred before the evolutionary separation of these two families 20-25 million years ago.

Animals↗
PubMed1996

Factors influencing the outcome of paramalleolar bypass grafts.

Reported patency rates for paramalleolar bypass grafts have varied widely. To determine factors predictive of outcome, we reviewed our experience with 80 consecutive paramalleolar reconstructions in 68 patients performed between December 1986 and May 1995. All procedures were performed for critical limb ischemia defined as nonhealing ulcer or gangrene (n = 72, 90%) and rest pain (n = 8, 10%). Risk factors present were diabetes (n = 52, 65%), hypertension (n = 64, 80%), and history of smoking (n = 57, 71%). Of the 80 bypasses, in situ saphenous vein conduits were used in 39 (49%). In the remainder non-in situ grafts were used including reversed vein (n = 25, 31%), composite vein (n = 11, 14%), polytetrafluoroethylene (PTFE; n = 4, 5%), and composite PTFE/vein (n = 1, 1%). The recipient vessel was the dorsalis pedis artery in 26 procedures (33%), the posterior tibial artery in 32 (40%), the distal anterior tibial artery in 18 (22%), and tarsal or plantar vessels in four (5%). Primary and secondary patency rates were 52% and 68% at 36 months, respectively, by life-table analysis. The limb salvage rate was 86% and patient survival was 56% at 36 months. Secondary patency was significantly higher in diabetic patients than in their nondiabetic counterparts (86% vs. 50% at 36 months, p < 0.03). Similarly, patients undergoing in situ reconstructions had better secondary patency than patients with non-in situ conduits (86% vs. 51% at 36 months, p = 0.03). Diabetic patients tended to be younger (median age 69 years vs. 72 years) and had fewer prior reconstructions (7 [13%] vs. 13 [46%], p < 0.01). Diabetic patients received a higher proportion of in situ reconstructions (54% vs. 39%) but the difference did not achieve statistical significance (p = 0.09). We conclude that the long-term patency for paramalleolar bypass is acceptable but inferior to reported figures for more proximal reconstructions. The factors that most influence patency are the quality of the venous conduit and the presence of diabetes. The improved patency seen in diabetic patients is likely related to the fact that these patients require paramalleolar bypass at an earlier age, are less likely to have had previous reconstructions, and are therefore more likely to have a good quality venous conduit.

Adult↗
PubMed1996

Effects of nicotine and amphetamine on latent inhibition in human subjects.

Latent inhibition (LI) is a phenomenon in which repeated non-reinforced exposure to a stimulus retards subsequent conditioning to that stimulus; it reflects a process whereby irrelevant stimuli become ignored, and has been the subject of study concerning attentional abnormalities in schizophrenia. Low doses of the indirect dopamine (DA) agonists, amphetamine and nicotine, disrupt LI in the rat. These drugs are believed to disrupt LI via DA release in the nucleus accumbens; LI in amphetamine- and nicotine-treated rats is reinstated by administration of the DA antagonist haloperidol. In human subjects, low doses of amphetamine abolish LI, and more recently haloperidol has been shown to potentiate LI. The present study investigated the effects of nicotine on LI in human subjects, and also attempted to replicate the abolition of LI by amphetamine. Nicotine failed to affect LI when administered either subcutaneously or by cigarette smoking. LI was, however, abolished in a group of subjects given 5 mg amphetamine 90 min before testing. Supplementary analyses of the data pooled from all three experiments showed that, in contrast to an earlier report, LI was no weaker in smokers than in nonsmokers.

Adult↗
PubMed1996

Miscarriage as a traumatic event: a review of the literature and new implications for intervention.

This review considers the psychological impact of miscarriage and follow-up care. A fifth of pregnancies end in miscarriage, and the experience leads to emotional consequences such as depression and anxiety, which may last for several months. Some have explored the focus of psychological morbidity and attempted to discover predictors of adjustment, but results are inconclusive. Grief has been identified as a feature of postmiscarriage distress, but trauma associated with the process of miscarriage has been neglected. Despite the recognized impact, there is dissatisfaction with professional emotional care, and there is no routine follow-up. There have been no controlled intervention studies with women who miscarry during early pregnancy, although anecdotal evidence suggests beneficial effects. Such studied have concentrated on loss, but perhaps future research should consider the whole experience of miscarriage. An intervention derived from trauma research has been suggested as a possible strategy for facilitating emotional adjustment and preventing longer term negative responses.

Abortion, Spontaneous↗
PubMed1996

The effect of xenobiotic acetylation on interorgan metabolism of glucose in fasted rats.

The effect of cytosolic acetylation on interorgan glucose metabolism was studied by arteriovenous (AV) difference and tracer kinetic techniques in fasted, ketamine-anesthetized rats. The administration of sulfamethazine (SMZ, 2 mmol/kg, i.p.) resulted in 39% and 313% increases in hepatic contents of glucose and lactate, respectively. Plasma concentrations of glucose and lactate in the aorta, portal vein and hepatic vein also increased (33-43% for glucose, and 86-200% for lactate). Net hepatic release of glucose was not significantly different from the control. Net hepatic uptake of lactate increased 72-151% in the SMZ-treated rats. The concentration and hepatic gradient of alanine were little changed in the SMZ-treated rats. The rates of turnover for plasma glucose, estimated from [3-3H]-glucose, were not significantly different between the control and SMZ-treated rats. The rate of glucose recycling, estimated from the difference in the rates of turnover between [3-3H]-and[U-14C]-glucose, decreased by 42% in the SMZ-treated rats. Muscle glycogen in the SMZ-treated rats also decreased (33%). In conclusion, our data indicate that cytosolic acetylation can affect not only ketogenesis, as we have previously reported, but also interorgan metabolism of glucose. Although direct evidence is not available, increases in the levels of plasma and liver glucose suggest that gluconeogenesis is increased in the SMZ-treated rats. A net loss of lactate from muscle glycogen store to the liver is indicated by the increase in hepatic uptake of lactate and the decrease in the rate of glucose recycling in the rats treated with SMZ.

Acetylation↗
PubMed1996

A noninvasive method in the differential diagnosis of vecuronium-induced and magnesium-induced protracted neuromuscular block in a severely preeclamptic patient.

The occurrence of neuromuscular blockade and the resulting potentiation of muscle relaxants during magnesium sulfate (MgSO4) administration is well known. However, a method to differentiate the neuromuscular block induced by magnesium from that induced by curariform nondepolarizing muscle relaxant in the clinical setting has never been reported. We report a case in which the duration of action of 1 mg of vecuronium lasted 4 hours in a patient with severe preeclampsia whose serum magnesium level was in the therapeutic range. We believe this is a remarkable potentiation on record in the literature. We also describe a new, noninvasive method to assess magnesium-induced neuromuscular block when curariform muscle relaxant was given simultaneously.

Adult↗
PubMed1996

Characterization of type I 5 alpha-reductase activity in DU145 human prostatic adenocarcinoma cells.

The conversion of testosterone (T) to dihydrotestosterone (DHT) has been demonstrated to be catalysed by at least two isoforms of human steroid 5 alpha-reductase, designated types I and II. Type II 5 alpha-reductase expression predominates in human accessory sex tissues, localized to the fibromuscular stromal compartment. The type I isoform predominates in skin, prostatic epithelia and, to a lesser extent, in prostatic fibromuscular stroma. The significance of the type I isoform to prostatic cellular growth and function remains undefined. In cultured DU145 cells, we evaluated the metabolism of [14C]-T and demonstrated the time-dependent formation of [14C]-DHT. Oxidative metabolism (conversion of [14C]-T to [14C]-androstenedione) and the formation of conjugated androgen metabolites occurred at a relatively low rate in the DU145 cells. Using human type I 5 alpha-reductase cDNA, Northern blot analysis of DU145 cell mRNA revealed high levels of type I isoform expression. Analogous probing of the DU145 cells with a human 5 alpha-reductase II cDNA failed to reveal expression of the type II isoform. The expression of functional type I activity has been confirmed pharmacologically using isoform-selective 5 alpha-reductase inhibitors. Reductive metabolism of [3H]-T in the DU145 cells was inhibited in a concentration-dependent manner by LY306089, a potent non-steroidal type I-selective inhibitor (IC50 = 10.0 nM). SKF105657, a steroidal type II-specific inhibitor was distinctly less active at inhibiting [3H]-DHT formation. LY306089 was a non-competitive inhibitor of type I 5 alpha-reductase in DU145 cellular homogenates with an apparent Ki value of 4.0 nM. These studies have identified and pharmacologically defined type I 5 alpha-reductase activity in an androgen-insensitive prostatic cancer cell line and provide the basis for additional investigations into the significance of type I 5 alpha-reductase to human prostatic pathophysiology.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1996

Arguing with the cognitivists.

A number of cognitivists have claimed that it is somehow illegitimate for those people who do not accept that cognitions are the only cause of human behavior to enter into debate on the issue. Their argument appears to be that it is not possible to develop an argument without making use of the sort of cognition described by Bandura [Bandura (1995) Comments on the crusade against the causal efficacy of human thought, Journal of Behavior Therapy and Experimental Psychiatry, 26, 179-190] and others, nor is it possible to influence other people without attempting to change their cognitive model of the topic, and therefore the mere fact of arguing is enough to disprove the non-cognitivists' position. This paper argues that argument is not dependent on an inner monologue but is a behavioral process; and attempting to persuade others does not necessitate a belief in a central causal role for cognitions. It is quite possible to engage in academic debate without adopting a dualist model of the human being, and, by extension, it is quite possible to explain a wide range of complex human activities without recourse to the limiting models of contemporary cognitive psychology.

Behaviorism↗
PubMed1996

Differential gene expression of transforming growth factors alpha and beta, epidermal growth factor, keratinocyte growth factor, and their receptors in fetal and adult human prostatic tissues and cancer cell lines.

OBJECTIVES: Recent studies have shown that growth factors may play a role in the etiology of benign prostatic hyperplasia (BPH) and prostatic carcinoma. Several growth factors have been reported to be expressed by prostatic tissues, but these growth factors have never been examined in human fetal prostate and compared with adult prostates and cancer cell lines. The present study was designed to investigate the messenger ribonucleic acid (mRNA) expression of transforming growth factor (TGF)-alpha, TGF-beta 1, TGF-beta 2, TGF- beta 3, keratinocyte growth factor (KGF), epidermal growth factor (EGF), EGF receptor (EGF-R), and KGF receptor (KGF-R) in human fetal and adult prostatic tissues and cancer cell lines by reverse-transcriptase-polymerase chain reaction-(RT-PCR) using specific oligonucleotide primers. METHODS: Total RNA was extracted from human fetal and adult prostates (BPH tissues) and cancer cell lines. The gene expression of these growth factors and their receptors was determined by RT-PCR using specific oligonucleotide primers. RESULTS: The results of these experiments suggest that: (1) human fetal prostate expressed mRNA transcripts for TGF-alpha, TGF-beta 1, TGF-beta 2, TGF-beta 3, and EGF. However, KGF, KGF-R, and EGF-R mRNA were not expressed by human fetal prostate; (2) human adult prostate (BPH tissues) showed mRNA transcripts for all growth factors and their receptors except KGF-R; (3) human BPH-1 cell lines expressed mRNA transcripts for TGF-alpha, TGF-beta 1, TGF-beta 2, TGF-beta 3, EGF, and KGF-R, but not for EGF-R and KGF growth factors; (4) human primary prostate cancer cell line (ND-1) showed mRNA transcripts for all growth factors except EGF and KGF; and (5) human prostate cancer cell lines (LNCaP, DU-145, PC-3) expressed mRNA transcripts for all growth factors except KGF, which was absent in all cell lines. However, KGF-R mRNA was absent in the PC-3 prostate cancer cell line. CONCLUSIONS: These results suggest that the differential gene expression for various growth factors and their receptors in human fetal and adult prostatic tissues and cancer cell lines may be important in understanding the role of these factors in the pathophysiology of prostatic diseases.

Adult↗
PubMed1996

An audit of the clinical features and use of antimicrobials in adult diarrhoea.

We reviewed the case records of 128 adult patients hospitalized with diarrhoea. A relevant stool pathogen was isolated from 45, a diagnosis of culture-negative or non-specific gastroenteritis (NSGE) was made in 40 and the remaining 43 patients had no enteric infection. A history of fever or bloody stools was more common in those with culture-positive gastroenteritis than it was in those with NSGE or other diarrhoeal illness. The mean duration of diarrhoea prior to admission was significantly shorter in those with all forms of gastroenteritis than it was in the remainder. Epirical treatment with ciprofloxacin was commenced in 46% of all cases of gastroenteritis, of which 51% were found to have a relevant pathogen on stool culture. Patients with NSGE were just as likely to be treated with ciprofloxacin as those who were subsequently found to have culture-positive gastroenteritis. A history of abdominal tenderness or bloody stools did not discriminate for treatment with empirical ciprofloxacin in any patient group. Patients with positive stool cultures were more likely to be given ciprofloxacin if they were febrile but the same was not true for the other patients. In the patients reviewed, a significantly higher proportion of those with culture-positive diarrhoea presented with a history of fever or bloody stools. Despite this, the empirical use of ciprofloxacin in suspected infective gastroenteritis appeared to be only partially guided by the clinical features.

Adult↗
PubMed1996

Ribavirin treatment for patients with chronic hepatitis C: results of a placebo-controlled study.

BACKGROUND/AIMS: Small, uncontrolled studies of ribavirin for patients with chronic hepatitis C have reported efficacy in chronic hepatitis C. We have evaluated the efficacy and safety of a 24-week course of oral ribavirin in patients with chronic hepatitis C, compared to placebo. METHODS: A total of 114 patients were randomised to ribavirin or placebo. Ribavirin was administered in doses of 1000 or 1200 mg/day for 24 weeks. Efficacy was determined in the intention-to-treat population: 76 received ribavirin and 38 placebo. RESULTS: Ribavirin was significantly more effective than placebo in reducing and normalising serum ALT levels: 42/76 (55%) of ribavirin-treated patients vs 2/38 (5%) placebo recipients had either normalisation of the ALT levels or a reduction from baseline of at least 50% (p < 0.001). ALT levels were normal in 22/76 (29%) of ribavirin-treated patients vs 0/38 placebo recipients (p < 0.001). Twenty-four weeks after stopping ribavirin, the majority of patients had abnormal ALT levels. There was no difference between the treatment groups in reduction or disappearance of HCV-RNA levels. HCV RNA disappeared during treatment in 3% of ribavirin-treated patients and 3% of placebo recipients. More ribavirin than placebo patients showed improvement in total Knodell score (45% vs 31%), but these differences were not statistically significant. Analysis of each component of a histology activity index revealed no statistically significant differences between treatment groups. Ribavirin patients had fewer lymphoid aggregates than did placebo recipients at the post-treatment assessment (p = 0.05). Ribavirin was associated with reversible haemolytic anaemia: a fall in haemoglobin occurred in 3% of placebo- and 32% (25/78) of ribavirin-treated patients, respectively (p < 0.001). CONCLUSIONS: These data indicate that ribavirin was no more effective than placebo in reducing or eliminating HCV-RNA levels, and was not significantly more effective than placebo in improving hepatic histology after 6 months of treatment. The role of a 6-month treatment of chronic hepatitis C with ribavirin alone, without a significant effect on HCV RNA, is therefore limited.

Administration, Oral↗
PubMed1996

Testing homology modeling on mutant proteins: predicting structural and thermodynamic effects in the Ala98-->Val mutants of T4 lysozyme.

BACKGROUND: Current approaches to homology modeling predict how amino acid substitutions will alter a protein's structure, primarily by modeling sidechain conformations upon essentially immobile backbone frameworks. However, recent crystal structures of T4 lysozyme mutants reveal significant shifts of the mainchain and other potentially serious problems for sidechain rotamer-based modeling. This paper evaluates the accuracy of structural and thermodynamic predictions from two common sidechain modeling approaches to measure errors caused by the fixed-backbone approximation. RESULTS: Tested on a series of T4 lysozyme mutants, this sidechain rotamer library approach did not handle mainchain shifts well, correctly predicting the sidechain conformations of only two of six mutants. By contrast, allowing sidechains to move more flexibly appeared to compensate for the rigidity of the mainchain and gave reasonably accurate coordinate predictions (rms errors of 0.5-1.0 A for each mutated sidechain), better on average than 90% of possible conformations. The calculated packing energies correlated well with experimental stabilities (r2 = 0.81) and correctly captured the cooperative interactions of several neighboring mutations. CONCLUSIONS: Mutant modeling can be relatively accurate despite the fixed-backbone approximation. Mainchain shifts (0.2-0.5 A) cause increased sidechain coordinate errors of 0.1-0.8 A, torsional errors of 10-30 degrees, and exaggerated strain energy for overpacked mutants, compared with the same calculations performed with the correct mutant backbones.

Bacteriophage T4↗
PubMed1996

DNA synthesis, microtubule and nuclear dynamics in porcine parthenotes.

Parthenogenetically activated mammalian oocytes have been used in the past decade as cytoplasts, in an attempt to support the development of nuclear transplant embryos. The present experiments were undertaken to study the DNA synthesis and the organisation of microtubules, nuclear envelope and chromatin during the first cell cycle of electrically activated porcine oocytes (parthenotes) matured in vitro by using immunocytochemistry and laser scanning confocal microscopy. The results showed that pronuclear-like (PN) formation began 4-5 h post-activation (hpa), whilst DNA synthesis as revealed by bromodeoxyuridine incorporation was initiated 5-6 hpa, with a maximum number of labelled oocytes (73%) around 11 hpa, and persisted in some parthenotes until 15-16 hpa. In the metaphase II (MII) oocytes, microtubules were detected only in the metaphase II spindle; no lamin A/C antigen was observed. Electrical DC pulses resulted in 91% of MII oocytes being activated and confocal microscopy indicated that microtubules were assembled in the spindle first for the extrusion of a second polar body, and for the second time for division from one to two cells. Nuclear envelope, indicated by anti-lamin A/C stain, was formed around the time of PN formation and surrounded the nuclear chromatin of 1- and 2-cell parthenogenotes. These results demonstrate that the apparent normality in both DNA synthesis and dynamics of microtubules and nuclear envelope is involved with chromosomal organisation in the parthenotes. In addition, the use of electrically activated IVM oocytes for both nuclear transfer and parthenogenetic studies in pigs is discussed.

Animals↗