Poly(ethylene glycol)-block-poly(L-lysine) dendrimer: novel linear polymer/dendrimer block copolymer forming a spherical water-soluble polyionic complex with DNA

Methoxypoly(ethylene glycol)-block-poly(L-lysine) dendrimer was designed to form a water-soluble complex with plasmid DNA. The copolymer was synthesized by the liquid-phase peptide synthesis method. It was characterized by 1H NMR and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrum. Agarose gel electrophoresis and DNase I protection assay proved that this linear polymer/dendrimer block copolymer assembled spontaneously with plasmid DNA, forming a water-soluble complex which increased the stability of the complexed DNA. Atomic force microscopy of the complex was evaluated at various charge ratios showing that the copolymer/DNA complex was like a globular shape.

Cyclodextrin removes cholesterol from mouse sperm and induces capacitation in a protein-free medium

Cyclodextrin, which stimulates cholesterol efflux from cells, was examined for its ability to induce capacitation of mouse spermatozoa. A chemically defined, protein-free medium was used for in vitro fertilization of cumulus-free mouse eggs. Fertilization did not occur in modified Krebs-Ringer bicarbonate medium (TYH) supplemented with 1 mg/ml polyvinylalcohol instead of BSA. However, fertilization was observed when spermatozoa were preincubated with methyl-beta-cyclodextrin (MBCD); fertilization rates increased dose-dependently from 0.25 to 0.75 mM MBCD. The fertilization rate decreased when 0.75 mM MBCD was added to both preincubation and fertilization media versus only the preincubation medium (21% vs. 53%); in sharp contrast, fertilization increased when 4 mg/ml BSA was present in both of the media versus the preincubation medium only (66% vs. 25%). At 0.75 mM, 2-hydroxy-beta-cyclodextrin had a lower ability to capacitate spermatozoa in vitro than MBCD (14% vs. 41%). Eggs fertilized by spermatozoa treated with MBCD (0.75 mM) developed to blastocysts (45%, 36 of 80) when cultured in KSOM. When 160 fertilized eggs were transferred to ICR recipients, 62 live offspring were born. After incubation of mouse spermatozoa for 90 min in 0.75 mM MBCD in TYH medium, the cholesterol content of the spermatozoa was significantly (p < 0.01) lower than that of the control (2.27 +/- 0.09 vs. 4.13 +/- 0.09 nmol unesterified cholesterol/10(7) sperm; mean +/- SEM, n = 5). The proportion of capacitated (B pattern) spermatozoa determined by chlortetracycline fluorescence was higher with MBCD treatment for 90 min than for the control (45% vs. 15%; p < 0.01). The proportion of acrosome-reacted (AR pattern) spermatozoa was not different between MBCD treatment and the control. Therefore, MBCD increased capacitation rather than the acrosome reaction of spermatozoa.

Pathophysiology of early failure of autologous aortic heart valves (ATCV)

BACKGROUND

Degeneration remains the major drawback of bioprostheses. Among various concepts to mitigate degeneration, the use of autologous pericardium for intraoperative construction of aortic valves (ATCV) was revived recently. Based on in-vivo studies the problem of tissue failure was claimed to be oversome by short immersion in glutaraldehyde.

METHODS

Two often ATCV implanted 1994-1996 had to be replaced because of valvular insufficiency due to leaflet shrinkage or tearing. Pathophysiology of failure was evaluated by light microscopy and immune histology, scanning electron microscopy (SEM) and determination of tissue calcium content (AAS).

RESULTS

AAS revealed high calcium levels in the shrunken and low levels in the torn leaflets. Histology demonstrated extensive fiber degeneration without inflammation in the destructed and moderate degeneration in the intact leaflets. SEM showed smooth surfaces in the 'normal' and exposure of collagen in the degenerated leaflet associated with calcification. Tears occurred close to the stents.

CONCLUSIONS

Failure of ATCV is characterised by either shrinkage and calcification despite a short tanning or by tearing related to the stent design. Clinical use of ATCV cannot be recommended at present.

Endoscopic treatment in a case with extensive spontaneous intramural dissection of the oesophagus

Spontaneous intramural dissection of the oesophagus has been recognized as a separate clinical entity between a transmural oesophageal rupture (Boerhaave syndrome) and an oesophageal mucosal tear (Mallory-Weiss syndrome). It is important to differentiate this condition from myocardiac infarction, dissecting aneurysm and other acute surgical conditions. Conservative management is usually thought to be adequate. We report a case of spontaneous intramural oesophageal dissection, in which the symptom of dysphagia did not improve with the conservative management and an endoscopic incision of the septum between true and false lumens using a needle-type diathermy knife was done safely and effectively.

Lactose-poly(ethylene glycol)-grafted poly-L-lysine as hepatoma cell-tapgeted gene carrier

To investigate the delivery of DNA into cells, lactose-poly(ethylene glycol)-grafted poly-L-lysine (Lac-PEG-PLL) polymers were synthesized as polymeric gene carriers. The new synthetic carriers, varying the substitution ratio of lactose-poly(ethylene glycol) (lactose-PEG), were characterized by NMR spectroscopy and size-exclusion chromatography. Electrophoretic mobility assay confirmed that the new gene carrier makes a complex with plasmid DNA. The attached poly(ethylene glycol) gives better solubility properties to gene/carrier complex. Transfection experiments showed that Lac-PEG-PLL efficiently delivers DNA to a hepatoma cell line in vitro; the best efficiency was achieved at a 1:3 weight ratio of DNA to carrier. As the lactose-PEG substitution content increased up to 30%, the transfection efficiency increased, which demonstrates that the lactose serves as a targeting moiety. No considerable cytotoxicity was observed due to Lac-PEG-PLL or its complex with DNA within the concentration range for this experiment. The use of chloroquine increased transfection efficiency that indicates the involvement of hydrolytic degradation of the system in lysosome. It is likely that plasmid DNA/Lac-PEG-PLL complexes enter the cells through a receptor-mediated endocytosis mechanism. These results show that Lac-PEG-PLL can form a complex with plasmid DNA and serve as an efficient gene delivery carrier with lower cytotoxicity compared to that of poly-L-lysine. Therefore, it is expected that our Lac-PEG-PLL carrier can be used as an in vivo gene delivery vector.

p21 expression and mutation in gastric carcinoma: analysis by immunohistochemistry and PCR-SSCP

p21 protein has been reported to be a critical downstream effector of p53 and a potent inhibitor of cyclin-dependent kinases. Thus, the p21 gene is thought to play a central role in tumor suppression. In this study we investigated p21 protein expression and mutation in gastric adenocarcinoma. A total of 76 primary gastric carcinoma specimens were immunohistochemically stained for p21 protein expression and evaluated the correlations between p21 expression and clinicopathologic features. In a proportion of them (20 cases), we also analyzed the possible presence of p21 gene mutations using PCR-SSCP method. Fourty seven out of 76 cases (61.8%) were p21-negative, and the remaining twenty nine cases (38.2%) were p21 -positive on immunostains. There was a correlation between the expression of p21, and the depth of tumor invasion and lymph node metastasis (p<0.05). No mutation of the p21 gene was detected in all of 20 tumor tissues. These results suggest that the status of p21 expression may have prognostic value in gastric adenocarcinoma.

Steroidal glycosides of the 14,15-seco-18-nor-pregnane series from Cynanchum ascyrifolium

Three new steroidal glycosides named cynascyrosides A-C were isolated from the roots of Cynanchum ascyrifolium. The structures of these compounds were determined on the basis of spectroscopic and chemical evidence as cynajapogenin A 3-O-alpha-D-oleandropyranosyl-(1-->4)-beta-L-cymaropyranosyl -(1-->4)-beta-D- digitoxopyranoside; cynajapogenin A 3-O-beta-D-glucopyranosyl-(1-->4)-alpha-L-cymaropyranosyl- (1-->4)-beta-L-cymaropyranosyl-(1-->4)-beta-L-cymaropyranoside+ ++; cynajapogenin A 3-O-beta-D-glucopyranosyl-(1-->4)-alpha-L-cymaropyranosyl- (1-->4)-beta-D-digitoxopyranosyl-(1-->4)-beta-L-cymaropyranosid e.

AP-2 may contribute to IGF-II overexpression in rhabdomyosarcoma

The human insulin-like growth factor II gene is regulated in a development-dependent manner and is not expressed in most adult tissues. However, high levels of insulin-like growth factor II mRNA are detected in many human tumors including rhabdomyosarcoma, an embryonal tumor of skeletal muscle origin. In this study, we demonstrate that the developmentally regulated transcription factor AP-2 is expressed at higher levels in human fetal skeletal muscle and rhabdomyosarcoma cells compared to human adult skeletal muscle. Endogenous insulin-like growth factor II mRNA derived from the P3 as well as transfected P3 promoter activity were modestly and consistently increased to the same extent following treatment of the rhabdomyosarcoma cell line RD with forskolin, a compound implicated in AP-2 transactivation. This effect of AP-2 on increased transcriptional activity was confirmed by nuclear run-on assays. Expression of AP-2B, a dominant-negative inhibitor of AP-2, suppressed the P3 promoter activity in AP-2 expressing RD cells. Furthermore, five AP-2 protected regions corresponding to six AP-2 specific binding sites were detected in the insulin-like growth factor II P3 promoter. These data together suggest that AP-2 may contribute to the high expression of IGF-II in rhabdomyosarcoma cells.

Morphology of tricuspid valve in pulmonary atresia with intact ventricular septum

Pulmonary atresia with intact ventricular septum (PAIVS) is a rare congenital cardiac anomaly that has been classified into two types: one is a more frequent type having dysplasia of tricuspid valve (TV) with a small annulus, underdeveloped right ventricle (RV) with a hypoplastic cavity and a hypertrophic wall; the other type has severe dysplasia of TV and dilatation of RV, right atrium (RA), and right atrioventricular junction with thinning of the RV wall. We performed a morphologic study on 11 autopsied hearts with PAIVS, giving particular emphasis to the variation of morphology of the TV. We could classify these hearts into 3 groups according to the degree of right ventricular development. In the first group of 7 cases (type I), the RVs were underdeveloped. Thick leaflets, restricted valve apparatus with short chordae, and small annuli were characteristics of the TV. In the second group of 3 cases (type II), the RVs showed marked enlargement of the cavity and thinning of the wall. The TV showed redundant, dysplastic, sail-like anterior leaflets, and the downward displacement of septal leaflet and/or posterior leaflet, which are the findings frequently observed in Ebstein's malformation. The RVs were dilated and with partially unguarded tricuspid orifice. The septal leaflet of the TV was dysplastic and, in two cases, the septal leaflet showed chordal structure at the upper surface facing the RA, which is a peculiar finding that has not been described in the literature. The remaining case was a heart with a moderately developed RV (type III). The TV showed mildly dysplastic appearance and we classify this as a separate type, because we could expect the best surgical results in this type. This type had optimal size of RV and the mildest degree of dysplasia of TV. In PAIVS, the morphology of TV correlates well with the type of the right ventricular development.

The effect of combined epidural and light general anesthesia on stress hormones in open heart surgery patients

This study was designed to evaluate the potential advantages of combined epidural and light general anesthesia over the commonly employed general anesthesia during open heart surgery. Twenty-four patients undergoing mitral valve replacement were thus studied. General anesthesia was maintained with an isoflurane-nitrous oxide-oxygen was mixture and morphine sulfate (0.4 mg/kg i.v. initially) followed by postoperative pain control with morphine in 12 patients (group GA). The remaining 12 patients (group EAA) received continuous epidural bupivacaine (0.125%)-morphine (50 micrograms/ml) supplemented with the same gas mixture as group GA. Epidural infusion was continued until the third postoperative day. Changes in the serum cortisol and beta-endorphin levels together with postoperative pain relief defined as good (scale 0-2), fair (3-4), or poor (5-10) were observed serially. Lower cortisol levels were observed in group EAA than in group GA (P < 0.05) just before skin closure, on the second and the third postoperative day. The beta-endorphin levels were substantially lower in group EAA than in group GA throughout the observation. The pain scores were good in 2 patients (17%), fair in 6 (50%), and poor in 4 (33%) for group GA, and good in 8 (67%), fair in 3 (25%), and poor in 1 (8%) for group EAA. We thus conclude that a combined epidural and light general anesthesia is considered to attenuate the stress response and thereby provides a better quality of postoperative pain control.

Genistein-induced G2/M arrest is associated with the inhibition of cyclin B1 and the induction of p21 in human breast carcinoma cells

Genistein is an isoflavone known to inhibit both tyrosine protein kinase and DNA topoisomerase II. We have investigated the mechanism of genistein-induced growth inhibition in MCF-7 and MDA-MB-231 breast carcinoma cell lines. DNA flow cytometric analysis indicated that genistein induced a G2/M arrest in both cell lines. Therefore, we examined the effect of genistein on cell cycle-related proteins. Western blot analysis using whole cell lysates from MCF-7 and MDA-MB-231 treated with genistein demonstrated that genistein treatment did not change the steady-state level of cdks, cyclin A, D-type cyclins and cyclin E protein, but inhibited expression of cyclin B1 protein in a time-dependent manner. The reduction in the protein level of cyclin B1 correlated with a decrease in the level of cyclin B1 mRNA. Genistein induced expression of p21, and the increased levels of p21 were associated with increased binding of p21 with cdc2 and cdk2. These observations suggest that genistein induces a G2/M arrest in human breast cancer cells, the mechanism of which is in part due to inhibition of kinase activities of cdc2 and cdk2, and decrease in cyclin B1 expression.

A case of primary bone lymphoma associated with acquired immunodeficiency syndrome

A 33-year old man with acquired immunodeficiency syndrome was admitted to Severance hospital following 1 year of diarrhea and 2 to 3 months of low sternal pain. The patient had progressive generalized lymphadenopathy for the previous 3 years. Whole body bone scan for evaluation of bone pain showed multiple abnormal hot uptakes at the low sternal body and T8 and T10 vertebra. Chest CT showed multifocal cortical erosion of the bone with soft tissue mass at the low sternal body and spine MRI showed multiple low-signal density in T1WI and high-signal density in T2WI at the T8 and T10 vertebral body. Biopsy was performed at the sternochondral junction and it showed high-grade malignant lymphoma of the large cell immunoblastic type. Immunostaining showed positive for the B-cell markers (CD79a and L26) and negative for the T-cell marker (UCHL1). Radiotherapy of 3,000 cGy was delivered to the sternum and vertebra. Since then, systemic chemotherapy with m-BACOD regimen (except dexamethasone) and anti-retroviral therapy with a combination of 3 drugs (didanosine, lamivudine, indinavir) has been performed. This is the first case report of primary bone lymphoma associated with acquired immunodeficiency syndrome in Korea.

Evaluation of fluids from cystic follicles for in vitro maturation and fertilization of bovine oocytes

Follicular cysts are defined as cystic structures derived from unovulated follicles. The formation of the cysts appears to be related to failure of the oocyte to resume meiosis. The aim of this study was to evaluate in the bovine: 1) the ability of the fluid from cystic follicles to promote in vitro oocyte maturation and fertilization, 2) the predictive value of the morphology of oocytes derived from cystic follicles on the ability of the follicular fluid to promote in vitro maturation/fertilization as well as the oocytes to undergo maturation and fertilization. In Experiment 1, the ability of fluid from cystic (and normal) follicles from live and slaughtered cows (to promote) in vitro maturation and fertilization of bovine cumulus-oocyte-complexes (COC's) was assessed by cumulus expansion, sperm penetration, male pronucleus formation and polyspermy rates. Concentrations of progesterone (P4) and estradiol-17 beta (E2) were measured in the fluid from cystic follicles collected from live and slaughtered cows. In Experiment 2, we investigated the relationship of the morphology of COC's from cystic follicles, and the effect of the follicular fluids on oocyte maturation as well as P4 and E2 concentrations. In Experiment 1, although sperm penetration and male pronucleus formation were inhibited significantly by fluid from some cystic follicles collected from live and slaughtered cows, there were no significant differences in sperm penetration, male pronucleus formation and polyspermy rates between fluid from cystic follicles collected from live cows, from slaughtered cows and from control groups, regardless of the P4/E2 ratio. In Experiment 2, the morphology of cumulus-oocyte complexes from cystic follicles varied and the pronucleus formation of oocytes after in vitro fertilization was abnormal. On the other hand, the male pronucleus formation rates were not significantly different between the cystic follicular fluids and control, regardless, of the P4/E2 ratio. The results of this study suggest that many of the bovine follicular fluids from cystic follicles possess the ability to induce cumulus expansion, nuclear maturation and male pronucleus formation following in vitro maturation and fertilization of bovine oocytes. The morphology of the cumulus-oocytes complexes from cystic follicles seems not to relate to the ability of the cystic follicular fluids to induce oocyte maturation, and oocytes from cystic follicles possess the ability to form male pronucleus even though most were abnormal after in vitro fertilization.

Appendiceal CT in 140 cases. Diagnostic criteria for acute and necrotizing appendicitis

Computed tomography (CT) was performed in 140 patients with suspected acute appendicitis. Thin collimation (5 mm), intravenous contrast enhancement, 1-second scan times, and supplementary cecal air insufflation were emphasized. CT accuracy was 98% overall (137/140), and 99% in the 124 cases with early surgery. Necrotizing appendicitis was diagnosed by CT with 86% accuracy and 90% positive predictive value.

Distribution of phosphate-activated glutaminase isozymes in the chicken: absence from liver but presence of high activity in pectoralis muscle

The distribution of glutaminase expression in a uricotelic species, the chicken, has been examined using cDNA probes to the rat isozymes. The results suggest that chickens do not possess a glutaminase isozyme equivalent to the liver-type isozyme of mammalian liver. Measurements of enzymic activity also showed very low glutaminase activity in chicken liver. Extra-hepatic tissues in the chicken do express a glutaminase isozyme mRNA which is detected by rat kidney-type glutaminase cDNA. The abundance of this mRNA was highest in kidney and breast muscle and relatively abundant in brain, spleen and adipose tissue. Chicken small intestine expressed relatively low levels of the mRNA. The high level of glutaminase mRNA in chicken pectoralis muscle was accompanied by high glutaminase enzymic activity. In contrast, in mixed leg muscle glutaminase mRNA was barely detectable by Northern blot and glutaminase activity was relatively low. Starvation for 48 h resulted in a slight decrease in the activity of glutaminase in pectoralis muscle, but a large decrease in the relative abundance of the mRNA. The results suggest that in the chicken, hepatic glutamine hydrolysis is not quantitatively important, but skeletal muscle may be a major site of glutamine catabolism.

Supercritical carbon dioxide extraction of podophyllotoxin from Dysosma pleiantha roots

Supercritical fluid extraction (SFE) was utilized to extract podophyllotoxin from the roots of Dysosma pleiantha. The extraction was carried out in the temperature range of 40-80 degrees C and the pressure range of 13.6-34.0 MPa with supercritical carbon dioxide. However, podophyllotoxin was not sufficiently extracted by pure supercritical carbon dioxide. Methanol was used as modifier to enhance the extraction yield of podophyllotoxin. As a result, SFE produced a higher recovery of podophyllotoxin than conventional 95% ethanol extraction.

Polyethylene glycol-grafted poly-L-lysine as polymeric gene carrier

A new series of gene carriers, polyethylene glycol (PEG)-grafted poly-L-lysine (PLL, mol. wt. = 25000) with three different PEG-grafted ratios (5, 10 and 25 mole%, which means 5, 10 and 25% of epsilon-amino group of PLL was modified by PEG), was synthesized. These new gene carriers, named comb-shaped PEG-g-PLL copolymer, showed a 5- to 30-fold increase in transfection efficiency compared to PLL alone on a human carcinoma cell line. It is likely that Hep G2 cells were transfected by plasmid DNA/PEG-g-PLL complexes through an endocytosis mechanism due to the fact that chloroquine increased transfection efficiency. Although Lipofectin, a cationic lipid formulation, showed slightly higher transfection efficiency than PEG-g-PLL in Hep G2 cells, our designed PEG-g-PLL demonstrated lower cytotoxicity, early gene expression and maintenance of gene expression for up to 96 h.

Oocyte quality of small antral follicles coexisting with cystic follicles in the ovaries of the cow

The present study was conducted with ovaries to evaluate the effect of the presence of a cystic follicle and its steroid hormone concentration on the oocyte recovery rates, oocyte morphology and in vitro maturation of the oocytes from coexisting small follicles. Ovaries, each bearing a follicular cyst (containing > 10 ml of follicular fluids, > 3 cm in diameter, and without a functional corpus luteum), were collected from each of the 26 Holstein cows from a local slaughterhouse. Small follicles (1-7 mm) from these ovaries were aspirated and their cumulus-oocyte complexes (COCs) classified into one of 5 groups (A to E), depending on oocyte and cumulus cell morphologies. Those oocytes with compact cumulus cells were cultured and their maturation rates determined. Concentrations of estradiol-17 beta (E2) and progesterone (P4) were measured in cystic follicular fluid using double antibody enzyme immunoassays (EIA). The morphology of the COCs and maturation rates of the oocytes were then evaluated using two comparisons. In first comparison, the left and right ovaries obtained from an individual cow were considered as a pair, with each pair being divided into two groups depending on the presence or absence of an E2 dominant or P4 dominant cystic follicle in one or another of the ovaries: E2 dominant cows; and P4 dominant cows. Oocytes collected from the ovaries of cyclic cows at follicular, luteal and post-ovulatory stages served as controls. The oocyte recovery rates, oocyte morphologies and oocyte maturation rates were independent of the presence or absence of a coexisting cystic follicle, or its steroid hormone classification or concentration. In the second comparison, each ovary was consider individually and divided into one of the two classes, depending on the presence or absence of a cystic follicle. Those ovaries with cystic follicles were then divided into three subclasses on the basis of E2 and P4 concentrations in the cystic follicular fluids: P4 dominant (P4/E2 ratio > 1); E2 dominant (P4/E2 ratio < 1); and both P4 and E2 dominant follicles present. The numbers of oocytes obtained from an ovary, their morphology and their maturation rates were not significantly different in the presence or absence of a coexisting cystic follicle. Moreover, the number of the oocytes aspirated from an ovary, their morphology and their maturation rates in small follicles coexisting with P4 dominant, E2 dominant and both P4 and E2 dominant cystic follicles were also not different. These results suggested that neither the presence of a cystic follicle in a cow's ovary nor the cyst's steroid hormone concentrations affected the oocyte recovery rate, oocyte morphology and maturation rates of the coexisting small follicles.

Inhibition of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase pathway induces p53-independent transcriptional regulation of p21(WAF1/CIP1) in human prostate carcinoma cells

Progression through the cell cycle is controlled by the induction of cyclins and the activation of cognate cyclin-dependent kinases. The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor lovastatin induces growth arrest and cell death in certain cancer cell types. We have pursued the mechanism of growth arrest in PC-3-M cells, a p53-null human prostate carcinoma cell line. Lovastatin treatment increased protein and mRNA levels of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1), increased binding of p21 with Cdk2, markedly inhibited cyclin E- and Cdk2-associated phosphorylation of histone H1 or GST-retinoblastoma protein, enhanced binding of the retinoblastoma protein to the transcription factor E2F-1 in vivo, and induced the activation of a p21 promoter reporter construct. By using p21 promoter deletion constructs, the lovastatin-responsive element was mapped to a region between -93 and -64 relative to the transcription start site. Promoter mutation analysis indicated that the lovastatin-responsive site coincided with the previously identified transforming growth factor-beta-responsive element. These data indicate that in human prostate carcinoma cells an inhibitor of the HMG-CoA reductase pathway can circumvent the loss of wild-type p53 function and induce critical downstream regulatory events leading to transcriptional activation of p21.

Effects of follicular fluid on fertilization and embryonic development of bovine oocytes in vitro

This study was conducted to evaluate the effect of bovine follicular fluid (BFF) on fertilizability and developmental capacity of bovine oocytes matured in vitro. Oocytes were collected from slaughterhouse ovaries, and matured in TCM199 supplemented with 5% superovulated cow serum (SCS), 2 mM pyruvate and 1 IU/mL PMSG. BFF was aspirated from small follicles (1 to 5 mm in diameter). In Experiment 1, BFF was added to the Brackett and Oliphant (BO) fertilization medium at concentrations of 0, 1, 5, 10 and 20%. After insemination with frozen-thawed and heparin-treated (10 micrograms/mL, 15 min) bull spermatozoa for 18 h, some of the oocytes were fixed and stained to evaluate the fertilization rate. The rest of the oocytes were co-cultured in serum-free embryo culture medium (ECM; TCM199 supplemented with 5% SCS, 2 mM pyruvate and 5 micrograms/mL insulin) with bovine oviductal epithelial cells (BOEC) at 38.5 degrees C under 5% CO2 in air, and the developmental capacity of embryos was examined at 2, 7 and 9 d. In Experiment 2, BFF was added to the serum-free ECM with BOEC at 0, 5, 10 and 20% concentrations, and embryos were cultured for 9 d. Fertilization rates and blastocyst rates in low (1 and 5%) BFF in fertilization medium were not significantly different from the control (without BFF). However, high concentrations of BFF (10 and 20%) in the fertilization medium suppressed both fertilization rates and development. Large vesicles with fast monolayer formation were observed at all concentrations of BFF added to ECM with BOEC. There were no significant differences in cleavage or development to blastocyst in different concentrations of BFF added to ECM. However, the rate of development to hatched blastocysts in 20% BFF was significantly lower than that of the control (P < 0.05). The results of the present study indicate that BFF addition to fertilization medium and ECM with BOEC does not improve fertilizability or developmental capacity and that high concentrations of BFF reduce the rate of both fertilization and development.

Developmental capacity of bovine oocytes matured in two kinds of follicular fluid and fertilized in vitro

This study was conducted to assess the ability of the follicular fluid derived from large and small follicles to support the in vitro oocyte maturation and subsequent fertilization and developmental capacity. Oocytes were cultured in bovine follicular fluid aspirated from small (SFF; 2-5 mm in diameter), large (LFF; 10 to 20 mm in diameter) follicles and TCM199 as a control under 5% CO2 in air. All maturation media were supplemented with 1 IU ml-1 pregnant mare serum gonadotropin. After 24 h culture, oocytes were fertilized in vitro with frozen-thawed and heparin-treated (10 micrograms ml-1, 15 min) bull spermatozoa and cultured in TCM199 with bovine oviductal epithelial cells (BOEC) for 7 days. Maturation of bovine oocytes cultured in LFF was inhibited and the low of male pronucleus formation was observed when compared with that of SFF (maturation rate: 69 vs. 78%; P < 0.05; male pronucleus formation rate: 58 vs. 80%; P < 0.05). Developmental capacity of bovine oocytes cultured in SFF was significantly (P < 0.05) higher than that of LFF (15 vs. 5%), but significantly (P < 0.05) lower than that of the control. There were no differences in the number of nuclei per blastocyst obtained after each treatment. These results indicate that the inhibitory action of follicular fluid on in vitro maturation, male pronucleus formation and developmental capacity of bovine oocytes is dependent on the developmental stage of the follicles from which fluid was obtained.

Imaging of the neurological complications of infective endocarditis

We describe the findings on CT or MRI in five patients with neurological symptoms and underlying infective endocarditis (IE). We noted the size, number, and distribution of lesions, the presence or absence of haemorrhage, and contrast enhancement patterns. The number of lesions ranged from 4 to more than 10 in each patient. Their size varied from punctate to 6 cm; they were distributed throughout the brain. The lesions could be categorized into four patterns based on imaging features. A cortical infarct pattern was seen in all patients. Patchy lesions, which did not enhance, were found in the white matter or basal ganglia in three. Isolated, tiny, nodular or ring-enhancing white matter lesions were seen in three patients, and parenchymal haemorrhages in four. In addition to the occurrence of multiple lesions with various patterns in the same patient, isolated, tiny, enhancing lesions in the white matter seemed to be valuable features which could help to differentiate the neurological complications of IE from other thromboembolic infarcts.

Effects of adenovirus-mediated p16INK4A expression on cell cycle arrest are determined by endogenous p16 and Rb status in human cancer cells

We constructed an adenoviral vector containing human p16 cDNA in order to evaluate the cytotoxic effects of exogenous p16 expression on cancer cell proliferation and to explore the potential use of p16 in cancer gene therapy. Following infection of human breast (MCF-7, MDA-MB-231, and BT549), osteosarcoma (U-2 OS and Saos-2), cervical (C33a), and lung cancer (H358) cell lines with the recombinant adenovirus Adp16, high levels of p16 expression were observed in all cell lines. Cancer cell lines which were mutant or null for p16 but wild-type for the retinoblastoma gene product (pRb) (MCF-7, MDA-MB-231, BT549 and U-2 OS) were 7-22-fold more sensitive to the cytotoxic effects of Adp16 than to a control virus. In contrast, cancer cell lines which were wild-type for p16 but mutant or null for pRb (Saos-2, C33a and H358) were <threefold more sensitive to Adp16 when compared to a control virus. Analysis of 5-bromodeoxyuridine incorporation into DNA following infection with Adp16 showed a loss of S phase in those cell lines which were null or mutant for p16 but expressed a functional pRb. This cell cycle arrest was associated with binding of the p16 protein to cyclin-dependent kinase 4 and dephosphorylation of pRb. In contrast, human cancer cell lines expressing a wild-type p16 and a mutant pRb or no pRb showed no substantial loss of S phase following Adp16 infection. Based on these studies, we conclude that p16-mediated cytotoxicity is tightly associated with the presence of functional pRb in human cancer cells, and that tumor cells which are mutant or null for p16 are candidates for Adp16 mediated cancer gene therapy.

Early failure of an autologous pericardium aortic heart valve (ATCV) prosthesis

BACKGROUND AND AIMS OF THE STUDY

The risk of reoperation due to calcific degeneration is the most important drawback of biological heart valves compared with mechanical prostheses. Concepts to mitigate calcification have been tested experimentally and clinically, but none has proven completely to prevent degeneration.

METHODS

Renewed interest has involved the use of autologous pericardium for intraoperative construction of autologous aortic valves (ATCV).

RESULTS

Of 10 ATCV implanted between 1994 and 1996, one was removed from an 84-year-old female 27 months after implantation because of severe valvular insufficiency. Eight months earlier, a broken spring of the stent system was detected radiographically, with normal valvular competence at echocardiography. Valve dysfunction was due to shrinkage of one leaflet. Measurement of tissue calcium by atomic absorption spectroscopy showed high levels in the shrunken leaflet compared with two intact leaflets (42.82 versus 0.51 and 2.42 mg Ca2+/g). Histology and immunohistology demonstrated extensive fiber degeneration without inflammation or immune reactions in the destroyed leaflet, and moderate fiber degeneration in intact leaflets. Scanning electron microscopy showed smooth surfaces in the normal leaflet and exposure of collagen in the degenerated leaflet in association with calcium deposition.

CONCLUSIONS

In contrast to the outcome in animal studies, intraoperative tanning did not prevent tissue shrinkage in this case. Leaflet malfunction was associated with calcification. At present, the clinical use of valves constructed from autologous pericardium can not be recommended.