Lack of Sharing of Spam1 (Ph-20) among Mouse Spermatids and Transmission Ratio Distortion1

Gametic equality is thought to exist, despite haploid gene action in mammalian spermiogenesis, because of product sharing via the intercellular bridges of conjoined spermatids. However, mice carrying different t-alleles have been known to produce functionally different sperm, leading to transmission ratio distortion (TRD), whose mechanism is unknown. The reduced Spam1 mRNA levels, previously shown to be associated with TRD and reduced fertility in mice carrying the Rb(6.16) or the Rb(6.15) Robertsonian translocation, are reflected in the levels of its encoded membrane protein (Spam1) and its accompanying insoluble hyaluronidase activity. Studies of the temporal expression pattern of Spam1 reveal that it is haploid expressed, with both the RNA and protein first appearing on Day 21.5. RNA fluorescence in situ hybridization and immunocytochemistry show both the mRNA and the protein to be compartmentalized. Compartmentalization of the mRNA along with its immediate translation and insertion of the protein in the plasma membrane suggests the nonsharing of Spam1 transcripts among spermatids, resulting in functionally different sperm in males with different Spam1 alleles. Evidence for biochemically different sperm in these heterozygous males was revealed by flow cytometry and confocal microscopy. Our findings support the notion that the Spam1 antigen is not shared, and we may have uncovered a mechanism for TRD.

[Development and evaluation of continuous-flow apparatus with spectrophotometer for fast reaction]

Microprocessor pump drive continuous-flow apparatus with spectrophotometer for study of fast reaction have been developed. The apparatus consists mainly of a microprocessor pump drive, an UV-240 spectrophotometer, a mix cell and the constant temperature facilities. The performance of this apparatus was evaluated by using the model system of Fe(III)-SCN- reaction. The rate constant values of this reaction system are in agreement with some other experimental results. According to the results of the experimental determination, we can see that this apparatus is easy to be operated and shows high precise in measurement. And the apparatus is suitable for kinetic studies of fast reactions whose half-life is in millisecond order.

Effects of a Brussels sprouts extract on oxidative DNA damage and metabolising enzymes in rat liver

The apparent anticarcinogenic effect of cruciferous vegetables found in numerous epidemiological and experimental studies has been associated with their influence on phase I and phase II metabolising enzymes as well as on the antioxidant status. In the present study we investigated the effect of administration of a Brussels sprouts extract on the expression at the mRNA level and/or catalytic activity in rat liver of three phase I enzymes [cytochrome P450-1A2 (CYP1A2),-2B1/2 (CYP2B1/2) and-2E1 (CYP2E1)] and two phase II enzyme [NADPH:quinone reductase (QR) and glutathione S-transferase pi 7 (GSTpi)], all previously suggested to be induced by vegetables. We also examined the activity and/or expression of several important antioxidant enzymes: glutathione peroxidase (GPx), catalase and gamma-glutamyl-cysteine synthetase (GCS) and the activity of the repair enzyme 8-oxoguanine DNA glycosylase (OGG1). QR, GPx and catalase activity was also assessed in the kidneys. In order to examine a possible effect of the Brussels sprouts related to oxidative stress, we measured oxidative DNA damage in terms of 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) and lipid peroxidation in terms of malondialdehyde (MDA) formation in the liver. Oral administration of an aqueous Brussels sprouts extract for 4 days was found to induce the expression of GST 1.3-fold (P < 0.05) and the activity of QR 2.6-fold in rat liver (P < 0.05). No significant differences were seen in the expression of the phase I enzymes. No differences in antioxidant enzyme activity/expression or OGG1 activity were observed. In a second experiment, administration of the Brussels sprouts extract for 3 or 7 days was found to increase the level of 8-oxodG in rat liver from 0.75 to 0.97 per 10(5) dG and from 0.81 to 0.97 per 10(5) dG, respectively (P < 0.05). No effects on MDA levels were found. The present results support the data obtained in several studies that consumption of cruciferous vegetables is capable of inducing various phase II enzyme systems. However, the observed increase in oxidative DNA damage raises the question of whether greatly increased ingestion of cruciferous vegetables is beneficial.

Phosphorylation of Bcl2 and regulation of apoptosis

Members of the Bcl2 family of proteins are important regulators of programmed cell death pathways with individual members that can suppress (eg Bcl2, Bcl-XL) or promote (eg Bax, Bad) apoptosis. While the mechanism(s) of Bcl2's anti-apoptotic function is not yet clear, introduction of Bcl2 into most eukaryotic cell types will protect the recipient cell from a wide variety of stress applications that lead to cell death. There are, however, physiologic situations in which Bcl2 expression apparently fails to protect cells from apoptosis (eg negative selection of thymocytes). Further, Bcl2 expression in patient tumor samples does not consistently correlate with a worse outcome or resistance to anticancer therapies. For example, patient response and survival following chemotherapy is independent of Bcl2 expression at least for pediatric patients with ALL. These findings indicate that simple expression of Bcl2 may not be enough to functionally protect cells from apoptosis. The finding that Bcl2 is post-translationally modified by phosphorylation suggests another level of regulation of function. Recent studies have shown that agonist-activated phosphorylation of Bcl2 at serine 70 (single site phosphorylation), a site within the flexible loop domain (FLD), is required for Bcl2's full and potent anti-apoptotic function, at least in murine IL-3-dependent myeloid cell lines. Several protein kinases have now been demonstrated to be physiologic Bcl2 kinases indicating the importance of this post-translational modification. Since Bcl2 phosphorylation has been found to be a dynamic process involving both a Bcl2 kinase(s) and phosphatase(s), a mechanism exists to rapidly and reversibly regulate Bcl2's activity and affect cell viability. In addition, multisite Bcl2 phosphorylation induced by anti-mitotic drugs like paclitaxel may inhibit Bcl2 indicating the potential wide range of functional consequences that this post-translational modification may have on function. While post-translational mechanisms other than phosphorylation may also regulate Bcl2's function (eg ubiquitination), this review will focus on the regulatory role for phosphorylation and discuss its potential clinical ramifications.

Emergence of new HIV-1 subtypes other than Subtype C among antenatal women in Lusaka, Zambia

Molecular epidemiology of HIV-1 in Zambia was investigated by direct sequencing of PCR products from samples collected from antenatal attendees in Lusaka, Zambia. One hundred and forty samples were initially screened for HIV, using antibody assays. Thirty-three (23.6%) samples were HIV-1 positive. Sequences of the HIV-1 env gp120 region were obtained from 28 of 33 (85%) HIV-1-positive samples. Twenty-six of the 28 sequences were HIV-1 env subtype C-like as previously reported. However, one HIV-1 env subtype D-like virus and one HIV-1 env subtype G-like virus were identified. This is the first time that these two HIV-1 env subtype viruses have been identified in Zambia, suggesting that more subtypes could be in existence.

Ceramide regulates protein synthesis by a novel mechanism involving the cellular PKR activator RAX

The sphingolipid ceramide is an important second signal molecule and potent apoptotic agent. The production of ceramide is associated with virtually every known stress stimulus, and thus, generation of this sphingolipid has been suggested as a universal feature of apoptosis. Recent studies suggest that an important component of cell death following diverse stress stimuli (e.g. interleukin-3 withdrawal, sodium arsenite treatment, and peroxide treatment) is the activation of the double-stranded RNA-activable protein kinase, PKR, resulting in the inhibition of protein synthesis (Ito, T., Jagus, R., and May, W. S. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 7455-7459). The recently discovered cellular PKR activator, RAX, is phosphorylated in association with PKR activation (Ito, T., Yang, M., and May, W. S. (1999) J. Biol. Chem. 274, 15427-15432). Since RAX is phosphorylated by an as yet undetermined SAPK and ceramide is a potent activator of SAPKs such as JNK, a role for ceramide in the activation of RAX might be possible. Results indicate that overexpression of exogenous RAX potentiates ceramide-induced killing. Furthermore, ceramide can potently inhibit protein synthesis. Since ceramide potently promotes RAX and eukaryotic initiation factor-2alpha phosphorylation, a possible role for ceramide in this process may involve the activation of PKR by RAX. Since 2-aminopurine, a serine/threonine kinase inhibitor that has previously been shown to inhibit PKR, blocks both the potentiation of ceramide killing by RAX and ceramide-induced inhibition of protein synthesis, ceramide appears to promote PKR activation, at least indirectly. Collectively, these findings suggest a novel role for ceramide in the regulation of protein synthesis and apoptosis.

In vitro degradation and release profiles for poly-dl-lactide-poly(ethylene glycol) microspheres containing human serum albumin

Poly-dl-lactide-poly(ethylene glycol) (PELA) block copolymers containing same the content (10%) of polyethylene glycol (PEG) were synthesized with five different molecular weight of PEG by ring-opening polymerization. PELA microspheres containing human serum albumin (HSA) were elaborated by solvent extraction method based on the formation of double w/o/w emulsion. In vitro matrix degradation and protein release of these microspheres were performed in phosphate-buffered saline (PBS) (154 mM, pH 7.43). The degradation profiles were characterized by measuring the loss of microspheres mass, the decrease of polymer intrinsic viscosity, the decrease of pH value of degradation medium, the reduction of polymer number-average molecular weight (M(n)) and the change of molecular weight polydispersity (M(w)/M(n)). The release profiles were investigated from the measurement of protein presented in the release medium at various intervals. It showed that the matrix degradation and protein release profiles were highly polymer-dependent. The extent of burst release in the initial protein release increased with the decrease of molecular weight of PELA copolymer. It is suggested that these matrix polymers may be optimized as carriers in protein (antigen) delivery system for different purposes.

Determination of diphenylamine stabilizer and its nitrated derivatives in smokeless gunpowder using a tandem MS method

A novel method for determination of diphenylamine (DPA) and its nitrated derivatives, which are considered as characteristic components in smokeless powder and gunshot residues, is described. A tandem mass spectrometric method is established and mass spectrometer parameters optimized for each compound to obtain higher sensitivity. Under optimum conditions, quantitative analysis was carried out. The linear ranges are 5.0-200.0, 2.0-200.0 and 5.0-250.0 ng ml-1 and the detection limits are 1.0, 0.5 and 2.5 ng ml-1 for diphenylamine (DPA), N-NO-diphenylamine (N-NO-DPA) and 4-NO2-diphenylamine (4-NO2-DPA), respectively. Intra-assay and inter-assay precision and accuracy of analysis of these three samples were investigated. Based on the regression lines obtained above, smokeless samples were analyzed. It was found that there are 0.952% DPA, 0.384% N-NO-DPA and 0.128% 4-NO2-DPA in smokeless powder. Recovery tests showed that using cotton swabs, 80.3 +/- 4.9% DPA, 79.6 +/- 3.1% N-NO-DPA and 83.1 +/- 5.4% 4-NO2-DPA could be recovered from human hands.

[Detection of telomerase activity and its clinical significance in colonic cancers by PCR-ELISA]

Using the recently developed telomerase PCR-ELISA detection kit, the authors detected the telomerase activity in 12 paired colonic cancer biopsies. It was found that strong telomerase activity was detected in all of the 12 colonic cancer tissues but not in adjacent non-cancerous tissues. These results suggest that the detection of telomerase activity by the PCR-ELISA assay could be used as a supplementary means for the diagnosis of colonic cancer.

[Anti-virus effect of combination of attenuated measles virus with 3TC on duck hepatitis B model]

OBJECTIVE

To evaluate the anti-virus effect of combination of attenuated measles virus with 3TC on duck hepatitis B model.

METHODS

Guanzhou brown spot ducklings infected with DHBV were divided into three groups. Drug treatments including measles vaccine, 3TC and both measles vaccine and 3TC were given in the 13th day after the infection, respectively. Serum samples were obtained from all ducklings before, during and after treatment at different times and stored at -70 degrees C. DHBV DNA was detected by Dot-blot hybridization.

RESULTS

Compared with the levels of DHBV DNA before and after treatment, no statistic difference was found in group of 3TC alone. The levels of DHBV DNA were not changed in group of measles vaccine alone in early stage, but decrease of DHBV DNA occurred after stopping treatment (comparison of the levels T13 with before treatment and T13 of positive group, P < 0.01 and P < 0.05, respectively). DHBV DNA level in group of measles vaccine combined with 3TC was obviously lower at 5th day after the treatment than in both measles vaccine and 3TC alone groups at the same time(P < 0.05 and P < 0.01, respectively), and it remained low when the treatment was discontinued.

CONCLUSION

Attenuated measles virus combined with 3TC may have early and long-lasting inhibiting effect on the replication of DHBV.

Secretory response of endothelin-1 in cultured human glomerular microvascular endothelial cells to shear stress

The shear-induced secretory response of endothelin-1 (ET-1) by human microvascular endothelial cells was studied using paired human glomerular microvascular endothelial cell (HGMEC) cultured monolayers exposed to steady-state laminar shear stress for up to 10 hours. The first cell monolayer was subjected to a shear stress of 0.65 N m-2 and the second, 1.3 N m-2. ET-1 secretion was determined by radioimmunoassay. Over 10 hours of shear, the total cumulative secretion of ET-1 was 237.4 pg/cm2 for the monolayer exposed to 1.3 N m-2 and 143.6 pg/cm2 for the monolayer exposed to 0.65 N m-2. The average ET-1 secretion rate was 20.90 +/- 2.15 and 12.45 +/- 1.05 pg/cm2.h at 0.65 N m-2 and 1.3 N m-2, respectively. The results showed that ET-1 secretion varied with the time of shear in a nonlinear fashion. Although the level of shear stress affected the absolute value of ET-1 cumulative secretion and secretion rate, the major secretion period for both monolayers occurred between 2.0 and 8.0 hours, with the peak secretion rate occurring at approximately 5 hours. Thus, the response of cultured human microvascular endothelial cells to shear stress differed from that of large vessel endothelial cell cultures in terms of ET-1 secretion. In addition to the level of shear stress, the time of shear was also an important determinant of ET-1 secretion. Consequently, the heterogeneity of vascular endothelial cells and the time of shear should both be considered in future research on the secretion of vascular endothelial cell cultures.

Effects of N-acetylcysteine on pulmonary macrophage activity after intestinal ischemia and reperfusion in rats / with invited commentaries

BACKGROUND/AIMS

Intestinal ischemia and reperfusion (I/R) is considered to be a critical and triggering event in the development of distal organ dysfunction after a variety of insults. It appears that activated leukocytes, especially polymorphonuclear granulocytes (PMNs), and reactive oxygen species are important mediators in the process. In the present study, the aim was to evaluate the behavior of pulmonary macrophages, acute lung injury and pulmonary endothelial permeability after intestinal I/R, together with potential alterations in pulmonary endothelial and epithelial ultrastructure and cellular membrane system integrity.

METHODS

Intestinal ischemia for 40 min was followed by reperfusion for 12 h in the rat. Macrophage uptake of radiolabeled bacteria, levels of pulmonary blood content assessed by radiolabeled red blood cells and pulmonary endothelial permeability of radiolabeled albumin, as well as pulmonary endothelial and epithelial ultrastructure and cellular membrane system integrity by the use of scanning electron microscopy and a tracer was evaluated after 12 h reperfusion. Treatment with the free radical scavenger N-acetylcysteine (NAC) administered prior to reperfusion was evaluated.

RESULTS

Overactivation of pulmonary macrophages was noted after intestinal I/R, as was a significant decrease in pulmonary blood content. No increase in pulmonary albumin leakage or increase in pulmonary water content was found after intestinal I/R as compared to controls. Treatment with NAC prevented against intestinal I/R-induced overactivation of pulmonary macrophages and a decrease in pulmonary blood content.

CONCLUSION

Reactive oxygen species may be involved in the regulation of pulmonary macrophage function and pulmonary circulation after intestinal I/R.

The effect of attenuated varicella-zoster virus on replication of HBV

OBJECTIVE

To observe the effect of attenuated varicella-zoster virus (VZV) on replication of HBV in vitro and vivo.

METHODS

The attenuated VZV were inoculated into the ducks infected with DHBV and into the cultural HepG(2) 2.2.15 cells, respectively. DHBV DNA, HBsAg and HBeAg were detected from the duck serum and cell cultural fluid by dot-blot hybridization and EIA.

RESULTS

The decline of DHBV DNA in duck serum was found in two dosage groups. Compared with pre-treatment, the level of AD value in 200 pfu/kg group was significantly decreased from 1.17+/-0.29 to 0.59+/-0.45 (10 day after VZV treatment) and 0.21+/-0.21 (5 day after withdrawal of VZV)(t =3.51, 7.54, P<0.001). The level in 400 pfu/kg group was from 0.70+/-0.25 to 0.32+/-0.17 on the 5th day of withdrawal of VZV (t =3.58, P<0.01), respectively after treatment. The inhibitory rates of HBeAg and HBsAg were 61% and 33%, respectively. The effect on HBeAg seems to be more obvious than on HBsAg.

CONCLUSIONS

Attenuated VZV could significantly decrease serum DHBV DNA in DHBV-infected ducks and directly inhibit the HBeAg and HBsAg secreted by 2.2.15 cells, suggesting that VZV seems to interfere or inhibit the replication of DHBV.

Cip4, a new COP1 target, is a nucleus-localized positive regulator of Arabidopsis photomorphogenesis

Arabidopsis COP1 acts within the nucleus to repress photomorphogenesis, and its nuclear abundance is negatively regulated by light. Here, we report the identification of a COP1-interactive partner, CIP4. CIP4 is a nuclear protein and a potent transcription coactivator. Conditional suppression of CIP4 expression resulted in an elongated hypocotyl and reduced chlorophyll content in the light, indicating that CIP4 is required for the promotion of photomorphogenesis. Furthermore, CIP4 was revealed to act downstream of multiple photoreceptors as well as COP1 in mediating light control of development. CIP4 expression is light inducible and regulated by COP1. However, CIP4 does not play a role in mediating the light induction of anthocyanin accumulation. Together with our previous studies of CIP7 and HY5, our data suggest that COP1 interacts directly with and regulates multiple physiological targets, which in turn regulate distinct sets of light-regulated responses.

Higher prevalence and viral load of TT virus in saliva than in the corresponding serum: another possible transmission route and replication site of TT virus

Although TT virus (TTV) is transmissible by blood or blood products, many patients with no history of transfusion of blood and blood products have been shown to be infected, suggesting other possible routes of transmission. To investigate the transmission routes and replication sites of TTV, 85 paired saliva and serum samples were studied by semi-nested polymerase chain reaction. The prevalence of TTV DNA was 38% (32/85 samples) and 21% (18/85) in saliva and serum, respectively. Fifteen patients had TTV DNA both in saliva and serum. Six out of fifteen patients had significantly higher viral titers in saliva than in serum, but none had higher titer in serum than in saliva. When the 222 base-pair nucleotide sequences of PCR products amplified from the samples were analyzed, 12 patients had the same genotype/subtype in saliva and serum and exhibited high homology (96-100%). The other 3 had different genotypes/subtypes in saliva and serum, and the homology was 61.9-87.2%. Mixed infection was observed both in saliva and serum. Further studies are required to determine if a subgroup of TTV has tropism to saliva. The high prevalence and viral load of TTV in saliva suggest that salivary fluid may be a possible route of transmission of TTV and that TTV might replicate not only in liver tissue but also in other tissues such as oropharyngeal tissues and/or salivary glands.

Oncogenic Ki-ras confers a more aggressive colon cancer phenotype through modification of transforming growth factor-beta receptor III

Transforming growth factor-beta1 (TGF-beta1) can act as a tumor suppressor or a tumor promoter depending on the characteristics of the malignant cell. Each of three Ki-ras(G12V) transfectants of HD6-4 colon cancer cells had been shown to be more aggressive in vivo than controls in earlier studies (Yan, Z., Chen, M., Perucho, M., and Friedman, E. (1997) J. Biol. Chem. 272, 30928-30936). We now show that stable expression of oncogenic Ki-ras(G12V) converts the HD6-4 colon cancer cell line from insensitive to TGF-beta1 to growth-promoted by TGF-beta1. Each of three Ki-ras(G12V) transfectants responded to TGF-beta1 by an increase in proliferation and by decreasing the abundance of the Cdk inhibitor p21 and the tumor suppressor PTEN, whereas each of three wild-type Ki-ras transfectants remained unresponsive to TGF-beta1. The wild-type Ki-ras transfectants lack functional TGF-beta receptors, whereas all three Ki-ras(G12V) transfectants expressed functional TGF-beta receptors that bound (125)I-TGF-beta1. The previous studies showed that in cells with wild-type Ki-ras, TGF-beta receptors were not mutated, and receptor proteins were transported to the cell surface, but post-translational modification of TGF-beta receptor III (TbetaRIII) was incomplete. We now show that the betaglycan form of TbetaRIII is highly modified following translation when transiently expressed in Ki-ras(G12V) cells, whereas no such post-translational modification of TbetaRIII occurs in control cells. Antisense oligonucleotides directed to Ki-Ras decreased both TbetaRIII post-translational modification in Ki-ras(G12V) cells and TGF-beta1 down-regulation of p21, demonstrating the direct effect of mutant Ras. Therefore, one mechanism by which mutant Ki-Ras confers a more aggressive tumor phenotype is by enhancing TbetaRIII post-translational modification.

Gene expression and gene therapy in experimental duodenal ulceration

Gastroduodenal ulceration is still poorly understood and changes in gene expression may provide new mechanistic insights. Previously, we demonstrated that angiogenic growth factors are potent ulcer healing agents, and the synthesis of bFGF, PDGF and VEGF is enhanced early in duodenal ulcer healing. The initial molecular event in duodenal ulceration seems to be the organ-specific early release of ET-1 in the pre-ulcerogenic stages after the administration of duodenal ulcerogen cysteamine in rats. We also briefly review here data from literature indicating a central role of ET-1 in gastroduodenal ulceration. After studying the involvement of immediate early genes (e.g. egr-1, Sp1) in ulcer development, we now investigated expression of other genes in the duodenal mucosa in the early stages of chemically induced duodenal ulceration in rats. Following a brief review of principles of gene expression and gene therapy, we review our preliminary gene expression studies, involving monitoring about 1200 genes which revealed about 160 signals and prominent changes in about 30 genes in the early stages of experimental duodenal ulceration. Cysteamine enhanced ET-B receptor gene expression in 30 min, while transcription factors (MAX, STAT 3) showed increased expression in 12 h. We recently also initiated gene therapy studies to enhance the local synthesis of PDGF and VEGF to accelerate duodenal ulcer healing, using a single dose of naked DNA (ND) or adenoviral (AV) vectors of VEGF and PDGF in rats with cysteamine-induced duodenal ulcers. Gene therapy with ND or AV of VEGF or PDGF significantly accelerated chronic duodenal ulcer healing, and increased levels of VEGF and PDGF were detected by Western blotting and ELISA in duodenal mucosa after both VEGF and PDGF gene therapy. Thus, gene expression studies provide new insights into the molecular mechanisms of duodenal ulceration and VEGF or PDGF gene therapy seems to be a new option to achieve a rapid ulcer healing.

The minimum alveolar concentration of enflurane for laryngeal mask airway extubation in deeply anesthetized children

The end-tidal anesthetic gas concentration required to prevent the anesthetized patient from coughing or moving during or immediately after the laryngeal mask airway (LMA) extubation is not known. We sought to determine the minimum alveolar concentration of enflurane required for the removal of the LMA in children. We studied 21 nonpremedicated children between 4 and 11 yr of age, ASA physical status I, undergoing procedures below the umbilicus. General anesthesia was induced with a mask by using sevoflurane, nitrous oxide, and oxygen, and the LMA was inserted. Anesthesia was maintained with enflurane, nitrous oxide, and oxygen. At the end of surgery, a predetermined end-tidal enflurane concentration was achieved, and the LMA was removed. Each concentration at which the LMA extubation was attempted was predetermined by the up-and-down method (with 0.1% as a step size). When LMA removal was accomplished without coughing, clenching teeth, or gross purposeful muscular movements during or within 1 min after removal, it was considered a successful LMA removal. Removal was considered to be unsuccessful in patients who developed breath holding or laryngospasm during or immediately after LMA removal. The minimum alveolar concentration of enflurane at which 50% of children had a successful LMA removal was found to be 1.02% (95% CL, 0.95%-1.11%), and the 95% effective dose for successful extubation was 1.14% (95% CL, 1.07%-1.66%). In conclusion, the LMA removal may be accomplished without coughing or moving at 1.02% end-tidal enflurane concentration in 50% of anesthetized children aged 4-11 yr.

IMPLICATIONS

There may be fewer problems associated with the laryngeal mask airway extubation when patients are deeply anesthetized. The purpose of this study was to determine the minimum concentration of enflurane for successful removal of the laryngeal mask in children.

Pulmonary sequestration: three dimensional dynamic contrast-enhanced MR angiography and MRI

In order to evaluate the diagnostic value of three-dimensional contrast-enhanced MR angiography and MRI for pulmonary sequestration, 5 patients with pulmonary sequestration underwent 3D fast imaging by steady state precession (FISP) with a contrast medium and breath holding following chest radiography, CT and MR scans. The reconstructed MR angiography was performed using maximum intensity projection (MIP) and multiplanar reconstruction (MPR) techniques. It was found that the chest radiography showed pulmonary sequestration as a persistent area of opacity in the posterior basal segment of the left lower lobe, which was close to mediastinum in 2 cases and close to diaphragma in 3 cases. CT revealed a soft issue mass beyond descending aorta and lobar emphysema around the pulmonary sequestration. And the supplying vessel was documented in 2 cases on enhanced CT. MRI demonstrated a hyperintensity mass with respect to normal lung parenchyma on T1WI and T2WI, and the origin of the supplying vessel in 3 cases. The reconstructed CE MRA using MIP or MRP techniques clearly showed the supplying vessel and its course, branches as well as draining vessels. It was concluded that 3D CE MRA of demonstrating the supplying and draining vessels to pulmonary sequestration, together with plain MRI, can provide a diagnosis and aid in surgical planning without the need for DSA.

In vitro protein release and degradation of poly-dl-lactide-poly(ethylene glycol) microspheres with entrapped human serum albumin: quantitative evaluation of the factors involved in protein release phases

PURPOSE

To quantitatively evaluate the correlations between the amount of initial burst release and the surface-associated protein, and between the onset time for the second burst release and the matrix polymer degradation.

METHODS

Human serum albumin (HSA) was microencapsulated in polylactide (PLA) and poly-dl-lactide-poly(ethylene glycol) (PELA) with PEG contents of 5, 10, 20, and 30%, respectively, using the solvent extraction procedure based on formation of double emulsion w/o/w. Microspheres with similar particle size (1.7-2.0 microm), similar protein entrapment (2.1-2.8%) but different surface-associated proteins (9.3-53.6%) were used to evaluate the in vitro matrix degradation and protein release profiles. Degradation was characterized by studying the intrinsic viscosity decrease, medium pH change, and weight loss of the microspheres.

RESULTS

The matrix degradation and protein release profiles were highly dependent on the polymer composition of the microspheres. Faster decreases in the intrinsic viscosity of recovered matrix polymer, the microspheres weight, and the pH of degradation medium, and earlier onsets for the break in intrinsic viscosity reduction and the mass loss were detected for PELA microspheres with higher PEG content. The hydration and swelling of microspheres matrix contributed greatly to the degradation of matrix polymer. The HSA release showed triphasic profile and involved two mechanisms for all the microsphere samples. Smaller amount of initial burst release, larger gradual release rate, and earlier onset for the second burst release were observed for HSA from matrix polymer with higher PEG content. The extent of the initial burst release was quantitatively related with the surface-associated protein. The second burst release of HSA was observed to occur within 1 week after the onset for mass loss, which was also the break in the intrinsic viscosity reduction rate.

CONCLUSION

Protein release profiles could be rationalized by optimizing the matrix polymer degradation and microsphere characteristics.

PYY potently inhibits pancreatic exocrine secretion mediated through CCK-secretin-stimulated pathways but not 2-DG-stimulated pathways in awake rats

Peptide YY (PYY) is an important modulator of stimulated pancreatic exocrine secretion. PYY acts proximal to the acinar cell but the exact site and mechanism of action are unknown. The aim of the present study is to determine the pathway through which PYY exerts its effect on the exocrine pancreas in awake rats under physiological condition. When pancreatic secretion was stimulated by graded doses of cholecystokinin (CCK) (14, 28, 58 pmol/kg/hr) with secretin (1.25, 2.5, 5.0 pmol/kg/hr) or CCK alone at 28 pmol/kg/hr, PYY1-36 dose-dependently inhibited pancreatic secretory responses. Moreover, PYY1-36 at 50 pmol/kg/hr almost completely blocked the stimulation by CCK (P < 0.01). Although background infusion of PYY1-36 or PYY3-36 at 12.5 pmol/kg/hr inhibited basal pancreatic fluid and protein secretion, but both of them only partly inhibited the subsequent 2-DG stimulated pancreatic fluid and protein secretion. Furthermore, PYY1-36 at 50 pmol/kg/hr failed to inhibit 2-DG-stimulated pancreatic secretion. These results confirm that PYY1-36 inhibits CCK-stimulated pancreatic secretion under all experimental conditions. However, in the awake, surgically recovered rat, PYY1-36 at both low and high doses failed to fully inhibit 2-DG-stimulated pancreatic secretion. Therefore, the site of PYY's inhibitory action on pancreatic secretion appears to be primarily on the CCK-stimulated pathway at a site proximal to the convergence of the CCK and 2-DG pathways.

The prognostic value of pretherapeutic tetranectin and CA-125 in patients with relapse of ovarian cancer

OBJECTIVE

The aim of the study was to examine the prognostic values of, respectively, tetranectin (TN) and CA-125 measured in serum from patients presenting with relapse of ovarian cancer (OC).

METHODS

TN and CA-125 were measured in serum samples from 75 patients with relapse of OC before the start of second-line chemotherapy. The endpoint used was death of OC. The variables were analyzed by univariate life table analysis and multivariate Cox analysis.

RESULTS

A significantly shortened survival was found for patients with low serum TN values compared to patients with serum TN levels above one of the cutoff levels. The survivals are illustrated by life tables. No prognostic function was found for CA-125. TN and relapse </=12 months after primary treatment were the only significant independent prognostic variables among the following variables tested in the Cox analyses: primary and second-line treatment, CA-125, age, histology, performance score, tumor localization, and size.

CONCLUSION

Serum TN determination may be valuable in the selection of patients with relapse of OC for new treatment strategies in future studies.

Effect of an annular pupil filter on differential confocal microscopy

Combining differential confocal microscopy and an annular pupil filter, we obtained the normalized axial intensity distribution curve of an optical system. We used the sharp slopes of the axial response curve of the optical system to measure the surface profile of a reflection grating. Experimental results prove that this method can extend the axial dynamic range and improve the transverse resolution of three-dimensional profilometry by sacrificing axial resolution.

Methamphetamine-induced neurotoxicity is attenuated in transgenic mice with a null mutation for interleukin-6

Increasing evidence implicates apoptosis as a major mechanism of cell death in methamphetamine (METH) neurotoxicity. The involvement of a neuroimmune component in apoptotic cell death after injury or chemical damage suggests that cytokines may play a role in METH effects. In the present study, we examined if the absence of IL-6 in knockout (IL-6-/-) mice could provide protection against METH-induced neurotoxicity. Administration of METH resulted in a significant reduction of [(125)I]RTI-121-labeled dopamine transporters in the caudate-putamen (CPu) and cortex as well as depletion of dopamine in the CPu and frontal cortex of wild-type mice. However, these METH-induced effects were significantly attenuated in IL-6-/- animals. METH also caused a decrease in serotonin levels in the CPu and hippocampus of wild-type mice, but no reduction was observed in IL-6-/- animals. Moreover, METH induced decreases in [(125)I]RTI-55-labeled serotonin transporters in the hippocampal CA3 region and in the substantia nigra-reticulata but increases in serotonin transporters in the CPu and cingulate cortex in wild-type animals, all of which were attenuated in IL-6-/- mice. Additionally, METH caused increased gliosis in the CPu and cortices of wild-type mice as measured by [(3)H]PK-11195 binding; this gliotic response was almost completely inhibited in IL-6-/- animals. There was also significant protection against METH-induced DNA fragmentation, measured by the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeled (TUNEL) cells in the cortices. The protective effects against METH toxicity observed in the IL-6-/- mice were not caused by differences in temperature elevation or in METH accumulation in wild-type and mutant animals. Therefore, these observations support the proposition that IL-6 may play an important role in the neurotoxicity of METH.

Methamphetamine-induced apoptosis is attenuated in the striata of copper-zinc superoxide dismutase transgenic mice

Administration of methamphetamine caused significant increases in terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells, in poly (ADP-ribose) polymerase (PARP) cleavage, as well as in caspase-3 activity in the striata of C57BL/6J mice. In contrast, all these effects were markedly suppressed in the copper-zinc superoxide dismutase transgenic mice. These results indicate that superoxide radicals might be important factors in METH-induced cell death.