Intracellular ATP-sensitive K+ channels in mouse pancreatic beta cells: against a role in organelle cation homeostasis

AIMS/HYPOTHESIS

ATP-sensitive K(+) (K(ATP)) channels located on the beta cell plasma membrane play a critical role in regulating insulin secretion and are targets for the sulfonylurea class of antihyperglycaemic drugs. Recent reports suggest that these channels may also reside on insulin-containing dense-core vesicles and mitochondria. The aim of this study was to explore these possibilities and to test the hypothesis that vesicle-resident channels play a role in the control of organellar Ca(2+) concentration or pH.

METHODS

To quantify the subcellular distribution of the pore-forming subunit Kir6.2 and the sulfonylurea binding subunit SUR1 in isolated mouse islets and clonal pancreatic MIN6 beta cells, we used four complementary techniques: immunoelectron microscopy, density gradient fractionation, vesicle immunopurification and fluorescence-activated vesicle isolation. Intravesicular and mitochondrial concentrations of free Ca(2+) were measured in intact or digitonin-permeabilised MIN6 cells using recombinant, targeted aequorins, and intravesicular pH was measured with the recombinant fluorescent probe pHluorin.

RESULTS

SUR1 and Kir6.2 immunoreactivity were concentrated on dense-core vesicles and on vesicles plus the endoplasmic reticulum/Golgi network, respectively, in both islets and MIN6 cells. Reactivity to neither subunit was detected on mitochondria. Glibenclamide, tolbutamide and diazoxide all failed to affect Ca(2+) uptake into mitochondria, and K(ATP) channel regulators had no significant effect on intravesicular free Ca(2+) concentrations or vesicular pH.

CONCLUSIONS/INTERPRETATION

A significant proportion of Kir6.2 and SUR1 subunits reside on insulin-secretory vesicles and the distal secretory pathway in mouse beta cells but do not influence intravesicular ion homeostasis. We propose that dense-core vesicles may serve instead as sorting stations for the delivery of channels to the plasma membrane.

A comparison of bone formation in biphasic calcium phosphate (BCP) and hydroxyapatite (HA) implanted in muscle and bone of dogs at different time periods

Physicochemical modification could implement synthetic materials into osteoinductive materials, which induce bone formation in nonosseous tissues. We hereby studied the relevance between the osteogenic capacities of osteoinductive materials in nonosseous tissues and in osseous sites. Biphasic calcium phosphate ceramic (BCP) and hydroxyapatite ceramic (HA) were implanted in femoral muscles and femoral cortical bone of dogs for 7, 14, 21, 30, 45, 60, 90, 180, and 360 days, respectively. Two dogs were used in each time point. In each dog, four cylinders (phi5x6 mm) per material were implanted in femoral muscles and 2 cylinders (phi5x6 mm) per material in femoral cortical bone. The harvested samples were processed for both histological and histomorphometric analyses. Bone was observed in BCP implanted in femoral muscles since day 30, while in HA since day 45. Quantitatively, more bone was formed in BCP than in HA at each time point after day 30 (p<0.05). The earlier and more bone formed in BCP than in HA suggests BCP a higher osteoinductive potential than HA in muscle. In femoral cortical bone defects, a bridge of bone in the defect with BCP was observed at day 21, while with HA at day 30. At days 14, 21, and 30, significantly more bone was formed in BCP than in HA (p<0.05). The results herein show that osteogenic capacities of osteoinductive materials in nonosseous tissues and osseous sites are correlated: the higher the osteoinductive potential of the material, the faster the bone repair.

Effect of PEG2000 on drug delivery characterization from solid lipid nanoparticles

The purpose of this work is to develop a PEG2000-modified solid lipid nanoparticles (SLN) intended to encapsulate a drug within their matrix and to study their characteristics. In the present report, drug-loaded SLN were prepared by a novel solvent diffusion method in an aqueous system. Monostearin and PEG2000 were used as carrier material and modifying agent, respectively. The model drug salbutamol sulphate was incorporated to study the characterization of entrapment efficiency, size, zeta potential (charge) and drug delivery characterization. In the test solution of pH 7.2 phosphate buffer, drug-release behavior from SLN suspension exhibited a biphasic pattern. With the monoastearin-based SLN, a distinctly prolonged release over a monitored period of 14 days was observed after a burst drug release in the first 8 hours. Over the monitored period of prolonged release, there was delayed release in the first 5 days with nearly 2.51% of the drug released each day, following which a slightly higher release rate (8.14% per day) appeared in the last 9 days. In contrast, the drug release rate from PEG2000-modified SLN was faster. Nevertheless, further work is required in order to optimize the release behavior of various entrapped drugs. These results also demonstrate that modification with PEG2000 can accelerate release of hydrophilic small molecule drugs from SLN.

Novel self-aggregates of chitosan oligosaccharide grafted stearic acid: preparation, characterization and protein association

A novel hydrophobically modified chitosan oligosaccharide (CSO) containing 5.4 stearic acid (SA) groups per 100 anhydroglucose units was synthesized by an 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The purified copolymer was structurally characterized by IR spectroscopy. Characteristics of self-aggregates of the amphiphilic copolymers were studied by fluorescence spectroscopy and dynamic light scattering. The critical aggregation concentration (cac) value of the self-aggregates in aqueous solution was determined by measuring the fluorescence intensity of pyrene as a fluorescent probe. Mean diameter of self-aggregates in pH 7.0 PBS was 25.0 +/- 14.7 nm with a unimodal size distribution. The diameter, as well as the zeta potential of self-aggregates increased when the pH value of dispersion medium decreased. Bovine serum albumin (BSA) was further enveloped in the interface of different single self-aggregate and formed nanoparticles. The size of BSA-loaded stearic acid modified CSO nanoparticles depended on the pH values of the dispersed aqueous vehicle, and the size diminished when the pH values of the dispersed aqueous vehicle decreased, whilst, the BSA encapsulation efficiency enhanced. The nanoparticles were characterized by Transmission Electron Microscopy (TEM). BSA release from stearic acid modified CSO nanoparticles decreased when the pH values of the delivery media decreased, in the range from 7.2 to 5.8.

Humanin delays apoptosis in K562 cells by downregulation of P38 MAP kinase

Humanin (HN) is a newly identified neuroprotective peptide. In this study, we investigated its antiapoptotic effect and the potential mechanisms in K562 cells. Upon serum deprivation, expression of HN in K562 cells decreased and its intracellular distribution changed from cytoplasm to cell membrane. In HN stably transfected K562 cells, apoptosis was delayed compared with control vector transfected cells as measured by flow cytometry. Furthermore, analysis of different mitogen-activated protein (MAP) kinases activity revealed that extracellular signal-regulated kinase (ERK) pathway was inhibited while p38 signaling was activated following serum deprivation in K562 cells. And in HN transfected K562 cells, ERK downregulation was not affected, but p38 activation was suppressed, which may responsible for the delayed apoptosis in these cells. Activation of the ERK signaling pathway by phorbol myristate 13-acetate (PMA) and sorbitol protected K562 cells from serum deprivation induced apoptosis. Additionally, overexpression of HN reduced megakaryocytic differentiation of K562 cells. The present data outline the role of ERK and p38 MAP kinases in serum deprivation induced apoptosis in K562 cells and figure out p38 signaling pathway as molecular target for HN delaying apoptosis in K562 cells.

RAMP based fingerprinting and assessment of relationships among Australian narrow-leafed lupin (Lupinus angustifolius L.) cultivars

Narrow-leafed lupin is a major winter grain legume crop in the Australian farming system and a number of commercial cultivars are currently available to growers. A significant level of polymorphism was detected in narrow-leafed lupin cultivars by the randomly amplified microsatellite polymorphism (RAMP) approach, suggesting that cultivars harbour considerable DNA variation. Seventy-seven cultivar-specific markers were found among the 23 lupin cultivars examined and a dichotomous fingerprinting key was developed for the molecular identification of lupin cultivars. Cluster analysis of pairwise distance matrix computed from RAMP profiles grouped the 23 cultivars into 4–5 clusters, which generally agreed with their pedigree relationships.

A novel preparation of solid lipid nanoparticles with cyclosporin A for prolonged drug release

Solid lipid nanoparticles were prepared by a novel solvent diffusion method in an aqueous system. The lipophilic model drug cyclosporin A was incorporated into SLN to study encapsulation efficiency, zeta potential (charge) and drug delivery. Stearylamine and cyclosporin A were dissolved in ethanol and acetone and the resultant organic solution was dropped into water at 60 degrees C. The drug-loaded SLN suspension quickly formed with an azury color. After burst drug release with 18% of the drug over the first 12 hours, a distinctly prolonged release over a monitored period of 16 days was observed, with nearly 4% of the drug being released each day. These results demonstrate the suitability of SLN produced with the proposed method as a prolonged release formulation for lipophilic drugs.

Preparation and characterization of solid lipid nanoparticles containing peptide

Solid lipid nanoparticles (SLN) are an alternative colloidal carrier system for controlled drug delivery. However, only a few have been studied regarding the incorporation of peptides into SLN, due to the hydrophilic peptide not easy to enter the lipophilic matrix of SLN. In the present report, peptide-loaded solid lipid nanoparticles were prepared by a novel solvent diffusion method in an aqueous system. The model peptide gonadorelin was incorporated to study the entrapment efficiency, size, zeta potential (charge) and drug delivery characterization. Gonadorelin and monostearin were dissolved in acetone and ethanol at 50 degrees C in water bath, the resultant organic solution was poured into an aqueous containing 1% polyvinyl alcohol (PVA) under mechanical agitation. The peptide-loaded solid lipid nanoparticles were quickly produced and separated by centrifugation. The average volume diameter of gonadorelin-loaded SLN is 421.7 nm and the zeta potential of SLN is -21.1 mV dispersed in distilled water. Up to 69.4% of gonadorelin can be incorporated. In vitro release of gonadorelin from SLN is slow. In the test solution of a 0.1N hydrochloric acid for 2h and then transferred in a pH 6.8 phosphate buffer (simulative gastrointestinal fluid), the drug-release behavior from SLN suspension exhibited a biphasic pattern. After burst drug-release at the first 6h at a percentage of 24.4% of loaded gonadorelin, a distinctly prolonged release over a monitored period of 12 days was observed and nearly 3.81% of drug was released in each day. In the test solution of a pH 6.8 phosphate buffer (simulative intestinal fluid), the drug-release rate from SLN was similar to that in the simulative gastrointestinal fluid. Further, a novel preparation method in the present research for peptide-loaded SLN was established. These results also demonstrate the principle suitability of SLN as a prolonged release formulation for hydrophilic peptide drugs.

Cloning of the KcURA3 gene and development of a transformation system for Kluyveromyces cicerisporus

KcURA3 was cloned from Kluyveromyces cicerisporus CBS4857 by complementation of the ura3 mutation in Saccharomyces cerevisiae. KcURA3 encodes a 267-amino-acid protein with 80% sequence identity to that of S. cerevisiae. An ura3 mutant strain from K. cicerisporus CBS4857, named Y179U, was obtained by selection on 5-fluoroorotic acid plates. Sequence analysis of this mutated gene revealed that it contained a point mutation at nucleotide position +277. Two vectors, pUK1 and pUKD, bearing KcURA3 were constructed. Either the lithium acetate method or electroporation could be used to transform pUK1 and pUKD intoY179U. The transformation efficiency using electroporation was higher than that using the lithium acetate method.

[Study on family aggregation of cases of advanced schistosomiasis japonica]

AIM

To explore the family aggregation of advanced schistosomiasis japonica.

METHODS

Eighty-one cases of advanced schistosomiasis(AS) and 67 cases of non-advanced schistosomiasis with history of infections in Yushan County, Jiangxi Province were chosen as proband groups and control groups respectively, then grades 1 and 2 relatives of them were investigated on AS. Family aggregation of AS was analyzed through comparing the prevalence rate between the close and distant relatives of probands and controls and fitting the observed distribution of AS cases among the population by zero-truncated Poisson distribution and zero-truncated negative binomial distribution.

RESULTS

The prevalence rate was higher in the close relatives (Group I relatives) of the probands than in the distant relatives(Group II relatives) of the probands and in the controls' relatives. The observed distribution of AS was beyond the probability of the zero-truncated Poisson distribution, but consistent with the zero-truncated negative binomial distribution.

CONCLUSION

Family aggregation of advanced schistosomiasis does exist.

Clinical trials in Alzheimer's disease. Calculating Alzheimer's Disease Assessment Scale-cognitive subsection with the data from the consortium to establish a registry for Alzheimer's disease

The database of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) is a seminal work in the field of cognitive dysfunction and Alzheimer's disease. This 24-center study of 1,094 patients with Alzheimer's disease who received no treatment for their cognitive dysfunction and 463 normal control subjects is rich in neurobehavioral data and contains extensive imaging and neuropathologic findings. However, the Alzheimer's Disease Assessment Scale (ADAS) was not administered as part of the CERAD study, which limits the study's applicability to modern drug trials, in which the ADAS-cognitive subsection (ADAS-cog) is a popular end point. The purpose of this investigation was to develop a derived ADAS-cog score from the neurobehavioral data obtained from subjects during their evaluation in the CERAD study. Two calculated ADAS-cog scores were developed. The first was based on clinically mapping the items on the ADAS-cog to assessments that were performed in the CERAD study. The second was based on rescaling the Mini-Mental Status Exam (MMSE), using published results correlating the ADAS-cog to the MMSE. Standard characteristics of both calculated ADAS-cog scores were calculated and compared with each other and with the literature. Both calculated ADAS-cog scores performed comparably to published characteristics of the ADAS-cog. The clinically based calculated ADAS-cog outperformed the rescaled MMSE. Using the CERAD database, it is now possible to model the progression of an untreated (placebo) population of patients with Alzheimer's disease and correlate it to a study using ADAS-cog.

Preparation of solid lipid nanoparticles with clobetasol propionate by a novel solvent diffusion method in aqueous system and physicochemical characterization

Solid lipid nanoparticles (SLN) are a colloidal carrier system for controlled drug delivery. Monostearin SLN were prepared by a novel solvent diffusion method in an acidic aqueous system in order to improve the recovery of the method. The lipophilic model drug clobetasol propionate was incorporated to study the recovery of nanoparticles, entrapment efficacy, zeta potential (charge) and drug delivery characterization. The drug and monostearin were dissolved in acetone and ethanol at 50 degrees C in water bath, the resultant organic solution was poured into an acidic aqueous (pH 1.10) containing 1% polyvinyl alcohol (PVA) under mechanical agitation at room temperature. The drug loaded SLN was quickly produced with an aggregation state and easily separated by centrifugation. The recovery of nanoparticles was markedly increased compared to using a usual aqueous (pH 5.73) containing the same concentration of PVA. After burst drug release at the first 3 h, a distinctly prolonged release over a monitored period of 4 days was observed and nearly 6% drug was released in each day. Further, a novel preparation method and the optimized separation parameters in the present research for SLN were established. These results also demonstrate the principle suitability of SLN as a prolonged release formulation for lipophilic drugs.

Measurement of vitellogenin gene expression by RT-PCR as a tool to identify endocrine disruption in Japanese medaka (Oryzias latipes)

In order to monitor vitellogenin gene expression in the Japanese medaka (Oryzias latipes), a reverse transcription-polymerase chain reaction (RT-PCR) system was developed. To date cDNA for medaka vitellogenin has not been published; therefore, initially a sequence fragment had to be obtained and compared with other known vertebrate vitellogenins. For this, a 1.2 kb cDNA of medaka vitellogenin (M-Vg1.2) was amplified by RT-PCR and cloned into a pCRR H-TOPO bacterial vector. On Northern blot analysis, the antisense cRNA of M-Vg1.2 stained a 5.5 kb gene product found exclusively in female fish, but not in males. Additionally, the 5'-end of medaka vitellogenin cDNA was amplified by 5'-RACE-PCR. The analysed nucleotide sequence of 1.6 kb shared significant similarities with vitellogenins known from other fish species: approximately 72% similarity with mummichog (Fundulus heteroclitus) vitellogenin I and approximately 62% with fathead minnow (Pimephales promelas) vitellogenin. To develop a semiquantitative RT-PCR for the measurement of vitellogenin gene expression, primers specific to a 500 bp sequence of the vitellogenin cDNA (M-Vg0.5) were constructed using the gene product of elongation factor 1 alpha as internal standard. Induction of vitellogenin gene expression was measured in male medaka exposed to 0, 2, 20 and 50 micrograms l-1 nonylphenol and 0, 2.5, 25 and 100 ng l-1 17 alpha-ethinyloestradiol for 7 days. The LOECs for vitellogenin induction in male medaka were 20 micrograms l-1 and 25 ng l-1 for nonylphenol and 17 alpha-ethinyloestradiol, respectively.

[The application of neural network to output estimation of an impeller artificial heart]

In this paper, several methods of output estimation of artificial heart are introduced briefly, and the authors put forward a method for the application of neural network to the output estimation of an impeller artificial heart. According to the laboratory results, the application of neural network can solve the problem successfully.

[Cytomegalovirus infection associated with plasma endothelin and P-selectin in patients with essential hypertension]

BACKGROUND

To investigate the relationship between human cytomegalovirus (HCMV) infection and plasma endothelin and P-selectin in patients with essential hypertension.

METHODS

Blood samples of 98 patients with essential hypertension were collected for HCMV IgM and IgG antibodies, plasma endothelin and plasma P-selectin by chemiluminescence technique, radio-immunoassay and ELISA.

RESULTS

The rates of positive HCMV IgM antibodies and positive rates for both HCMV IgM and IgG antibodies were 56.12% and 54.08%, respectively, which were higher than that of the control group (P=0.05). The level of plasma endothelin and P-selectin in patients with positive HCMV IgM antibodies was 95.53 +/- 5.06 ng/ml and 42.50 +/- 3.28 ng/ml, respectively, which were higher than that in patients with negative HCMV IgM antibodies (71.60 +/- 4.34 ng/ml and 27.41 +/- 5.28 ng/ml) and that of the control group (48.77 +/- 5.96 ng/ml and 19.80 +/- 4.62 ng/ml).

CONCLUSIONS

These results suggest that HCMV active infection may aggravate vascular endothelium lesi on in patients with essential hypertension and contribute to the increase of endothelin and P-selectin.

[Sequence analysis of mtDNA 12S rRNA, tRNA(Leu(UUR)),tRNA(Ser(UCN))and 16S rRNA gene of 12 nonsyndromic inherited deafness pedigrees]

OBJECTIVE

To detect the relationship of mtDNA mutation with inherited deafness and the reason for pedigree's hypersensitivity to ototoxicity of aminoglycoside antibiotics(AmAn).

METHODS

Pedigree investigations were conducted. The blood samples were obtained from 12 pedigrees, and DNA was extracted from the isolated leukocytes. After that, mtDNA fragments were amplified by PCR. The 1555(G), 3243(G) and 7445(G) mutations were detected by Alw 26 I, Apa I and Xba I restriction endonuclease digestion respectively, and then sequencing of 12S rRNA, tRNA(Leu(UUR)), tRNA(Ser(UCN))and 16S rRNA gene was performed.

RESULTS

Restriction endonuclease digestion and sequence analysis showed that all the pedigrees carried mtDNA mutation, among them, 10 pedigrees carried 1555(G) mutation; 2 pedigrees, 7445(G) mutation; no pedigree was found to harbor the 3243(G) mutation. Sequence analysis of 16S rRNA gene showed that the mutations are 2230(G), 2230(AG), 2243(AG), 2230(AA).

CONCLUSION

The pedigrees that carried 1555(G) or 7445(G) mutation showed hereditary or congenital hearing loss. The 1555(G) or 7445(G) mutation in association with 16S rRNA gene mutation led to pedigree's hypersensitivity to AmAn ototoxicity.

[Study on some metal elements levels and the T lymphocyte subset of the peripheral lymphocytes in patients with nasopharyngeal carcinomas]

OBJECTIVE

To study some metal elements levels and T lymphocyte subset of the peripheral lymphocytes in patients with nasopharyngeal.

METHOD

Metal elements in the patients with nasopharyngeal and normal control were detected by the Atomic Absorption Spectrometer (Flame SHIMATZV.JAPAN). T lymphocyte subset were detected by the flow cytometry (FCM).

RESULT

The level of copper was significantly higher and the level of zinc was significantly lower in patients with nasopharyngeal carcinomas than those in normal control group (P < 0.01 and < 0.05 respectively). The number of CD3/CD4 cell in the patients group were less than those in normal group(P < 0.01).

CONCLUSION

The results of correlative analysis showed that there was a significant correlationship between the number of CD4 cells and levels of copper in peripheral lymphocytes of the patients group.

Material-dependent bone induction by calcium phosphate ceramics: a 2.5-year study in dog

Bone induction by different calcium phosphate biomaterials has been reported previously. With regard to (1) whether the induced bone would disappear with time due to the absence of mechanical stresses and (2) whether this heterotopically formed bone would give rise to uncontrolled growth, a long-time investigation of porous hydroxyapatite ceramic (HA), porous biphasic calcium phosphate ceramic (TCP/HA, BCP), porous alpha-tricalcium phosphate ceramic (alpha-TCP) and porous beta-tricalcium phosphate ceramic (beta-TCP) was performed in dorsal muscles of dog, for 2.5 years. Histological observation, backscattered scanning electron microscopy observation and histomorphometric analysis were made on thin un-decalcified sections of retrieved samples. Normal compact bone with bone marrow was found in all HA implants (n = 4) and in all BCP implants (n = 4), 48 +/- 4% pore area was filled with bone in HA implants and 41 +/- 2% in BCP implants. Bone-like tissue, which was a mineralised bone matrix with osteocytes but lacked osteoblasts and bone marrow, was found in all beta-TCP implants (n = 4) and in one of the four alpha-TCP implants. Both normal bone and bone-like tissues were confined inside the pores of the implants. The results show that calcium phosphate ceramics are osteoinductive in muscles of dogs. Although the quality and quantity varied among different ceramics, the induced bone in both HA and BCP ceramics did neither disappear nor grow uncontrollably during the period as long as 2.5 years.

Application of solid-phase microextraction in the determination of diazepam binding to human serum albumin

In this paper, protein-drug interactions were studied by solid-phase microextraction (SPME) using diazepam binding to human serum albumin as a model system. Since drug compounds are normally polar and nonvolatile by nature, direct SPME is used in this work. The SPME extraction is an equilibrium process among the concentrations of the analyte partitioned onto the SPME fiber, free and bound drug in the solution. A calibration curve was first constructed by employing the amount of the analytes partitioned on the fiber versus the free analyte concentration in the solution in the absence of protein. In method I, the extraction was performed in the protein solution with known diazepam concentration. In method II, diazepam was first loaded onto the fiber by extracting in solution with known diazepam concentration. This fiber was subsequently transferred into the protein solution for desorption. The amount of the analyte left on the fiber was analyzed after the system reached equilibrium. The free drug concentration was then obtained from the calibration curve for both methods. The Scatchard plot was finally employed to obtain the number of binding sites and the equilibrium binding constants. Since only a very small amount of the protein solution is required (150 microL for each extraction), method II is very useful for circumstances where the protein amount is very limited. The direct measurement method proposed in this paper does not need a GC response factor, which significantly decreases the experimental error. The only measurement needed is the area count change (ratio) of the fiber injections before and after the protein was introduced into the solution. The difference between the direct measurement method for method I and method II is discussed. The result illustrated that the SPME direct measurement method provided both theoretical accuracy and simplicity in such applications.

[Improved retrosigmoid approach operation in the treatment of trigeminal neuralgia]

OBJECTIVE

To explore the surgical method which can raise the treatment effect and reduce the complication occurrence of cerebellopontine angle (CPA) operation by retrosigmoid approach.

METHOD

Have improved the retrosigmoid approach in the skin incision, the hole position of bone, the intracranial operation skills and the duramatral suture, etc. By the improved retrosigmoid approach, we used partial sensory rhizotomy (PSR) to cure 54 cases with trigeminal neuralgia (TN).

RESULT

52 cases got satisfactory treatment effect and no complication appeared. In the other 2 cases, the trigeminal nerve was not found in CPA.

CONCLUSION

The CPA operation by retrosigmoid approach is dangerous relatively, it usually can cause some serious complication. But improved retrosigmoid approach can expose CPA sufficiently and is convenient to operate. On the other hand, it can decrease intracranial unexpected hemorrhage and complication occurrence.

[Pulsatile rotary pumps with low hemolysis]

As is well known, a pulsatile flow is important in assisted-circulation but it is difficult to produce a pulsatile flow with rotary pump, because excessive hemolysis will be generated. The authors have found that the turbulent shear is the main factor for red cell damage and therefore the key point of pulsatile rotary pumps is to reduce the turbulence by producing a pulsatile flow. In the authors' pulsatile axial pump, the pulsatile flow is obtained by axial reciprocation of constant rotating impeller; the rotation and reciprocation of the impeller are driven separately by a DC motor and a pneumatic device. Though a physiological pulsatile flow could be achieved and turbulence would not increase remarkably because the impeller rotates constantly, a second driver except a DC motor is nevertheless necessary, thus the system will become complicated. In the authors' pulsatile radial pump, a pulsatile flow is achieved by changing the rotating speed of the impeller periodically. Turbulence is minimized by a special design of twisted vanes which enable the blood flow to change its direction rather than its dimension during periodic change of rotating speed. Hemolysis tests demonstrated that the index of hemolysis(IH) of the author's pulsatile radial pump is 0.020, with is slightly more than that of the author's nonpulsatile radial pump(IH = 0.015). Animal experiments indicated that the pulsatile radial pump can assist the circulation of calves for several months without harm to blood elements and organ functions of the recipients.

Immunization with a pentameric L1 fusion protein protects against papillomavirus infection

The prophylactic papillomavirus vaccines currently in clinical trials are composed of viral L1 capsid protein that is synthesized in eukaryotic expression systems and purified in the form of virus-like particles (VLPs). To evaluate whether VLPs are necessary for effective vaccination, we expressed the L1 protein as a glutathione S-transferase (GST) fusion protein in Escherichia coli and assayed its immunogenic activity in an established canine oral papillomavirus (COPV) model that previously validated the efficacy of VLP vaccines. The GST-COPV L1 fusion protein formed pentamers, but these capsomere-like structures did not assemble into VLPs. Despite the lack of VLP formation, the GST-COPV L1 protein retained its native conformation as determined by reactivity with conformation-specific anti-COPV antibodies. Most importantly, the GST-COPV L1 pentamers completely protected dogs from high-dose viral infection of their oral mucosa. L1 fusion proteins expressed in bacteria represent an economical alternative to VLPs as a human papillomavirus vaccine.

Use of an osteoinductive biomaterial as a bone morphogenetic protein carrier

A porous calcium phosphate ceramic, which induced bone formation in soft tissues of dogs, was termed as osteoinductive biomaterial and studied as a carrier of bone morphogenetic protein (rhBMP-2). Cylinder implants (laser spot 4 x 5 mm) impregnated with 0, 1, 10 and 40 microg rhBMP-2 were implanted in dorsal muscles of rabbits for five weeks. Histological observation and histomorphometric analysis were performed on thin un-decalcified sections. No bone formation was detected in the implants without rhBMP-2, while mature lamellar bone was found inside the implants with 1 microg rhBMP-2, both on the outer surface and inside the implants with 10 microg and 40 microg rhBMP-2. Little difference in formed bone was found between 1 microg and 10 microg rhBMP-2, but no difference was found between 10 microg and 40 microg rhBMP-2. A significant difference in bone marrow formation was found among 1, 10 and 40 microg rhBMP-2. The more rhBMP-2, the more bone marrow formed. The present results indicate that osteoinductive biomaterial is a good carrier of BMP and high dose of BMP is not necessary for bone formation in clinic.

[Study of quantitative calibration model suitability in near-infrared spectroscopy analysis]

Near-infrared spectroscopy is a fast, high efficiency and low cost analytical technique, that depended on analytical models which are built through near-infrared spectra, the primary method results of calibration set and chemometrics methods. The reliability of analytical results mostly depends on the suitability of analytical model to unknown samples. To judge the suitability of analytical model, a new method is presented that combine principle factor analysis (PCA) and Mahalanobis distance. It is different with traditional method, that the Mahalanobis distance is calculated through PCA factor scores. It can avoid the wavelengths selection problem in traditional method of spectral Mahalanobis distance. Through the determination of cetane number of diesel fuel, some factors that affect model suitability judgement are discussed.

Mutations in the novel protocadherin PCDH15 cause Usher syndrome type 1F

We have determined the molecular basis for Usher syndrome type 1F (USH1F) in two families segregating for this type of syndromic deafness. By fluorescence in situ hybridization, we placed the human homolog of the mouse protocadherin Pcdh15 in the linkage interval defined by the USH1F locus. We determined the genomic structure of this novel protocadherin, and found a single-base deletion in exon 10 in one USH1F family and a nonsense mutation in exon 2 in the second. Consistent with the phenotypes observed in these families, we demonstrated expression of PCDH15 in the retina and cochlea by RT-PCR and immunohistochemistry. This report shows that protocadherins are essential for maintenance of normal retinal and cochlear function.

Biological sample analysis with immunoaffinity solid-phase microextraction

A theophylline antiserum was covalently immobilized on the surface of a fused silica fiber, modified with 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde, and used as a selective and sensitive extraction medium for the immunoaffinity solid-phase microextraction (SPME) determination of theophylline in serum samples. The specificity of the immunoaffinity SPME fiber was first investigated using a fixed concentration of [3H]theophylline together with various amounts of interference, possessing no cross-reactivity with the theophylline antibody. No significant non-specific binding was observed. The reproducibility of the fiber preparation and the immunoaffinity SPME analysis was also investigated, resulting in a relative standard deviation of 6.1% for five analyses of the same fiber. The antigen-antibody binding isotherm was obtained by analyzing theophylline standards of various concentrations (0.1-5 ng mL(-1)) until saturation values were reached. Initial binding of theophylline was linear with a r2 = 0.968. The cross-reactivity of the theophylline immunoaffinity SPME fiber for the structural analog caffeine was investigated by adding various amounts of caffeine in the presence of theophylline at a saturation concentration and produced a low cross-reactivity value of 0.1%. Finally. spiked serum samples (10 and 50 ng mL(-1)) were successfully analyzed with an excellent correlation with the standard binding isotherm, thus confirming the performance of the immunoaffinity SPME coating for improved bioanalysis.

Topological indices based on vertex, distance, and ring: on the boiling points of paraffins and cycloalkanes

Vertex, distance, and ring (in cyclic compounds) are three essential structure elements of a molecular graph, based on which three new topological indices VDI, OEI, and RDI are proposed. Multiple regression analysis was carried out against the boiling points of 343 hydrocarbons(160 paraffins and 183 cycloalkanes) with VDI, OEI, RDI, and N(2/3)(N is the number of carbon atoms) together, and a good QSPR model was obtained: ln(577 - Bp) = 6.729609 - 0.154107N(2/3) + 2.285632 x 10(-2)VDI - 7.921410 x 10(-3)OEI - 1.821962 x 10(-2)RDI (F = 6455.09, r = 0.9935, rms = 6.44 degrees C, n = 343).

Differential processing of cytosolic and mitochondrial caspases

The mitochondria have been shown to play a key role in the initiation of caspase activation during apoptosis. Recently, some caspases have been shown to be associated with mitochondria. In this study, we used Jurkat T-lymphoblasts to show that caspases -2 and -3 are located in the mitochondrial intermembrane space, associated with the inner membrane. Caspase-9 is associated with the outer membrane and is exposed to the cytosolic compartment. Caspase activation took place predominantly in the cytosol in response to Fas ligation, but staurosporine treatment led to caspase activation in both cytosol and mitochondria. In response to both Fas and staurosporine treatment, caspase processing could be detected earlier in cytosol than in mitochondria, but this could reflect the limits of sensitive detection by immunoblotting. Only trace amounts of Apaf-1 were found in association with the mitochondria. However, staurosporine treatment led to preferential auto-processing of caspase-9 associated with mitochondria. These findings suggest that mitochondrial caspases are regulated independently of the cytosolic pool of caspases. The data are also consistent with the notion of a caspase nucleation site associated with mitochondria. Using a stable transfected CEM cell line, we show that Bcl-2 suppressed caspase processing in both cytosolic and mitochondrial compartments in response to both staurosporine and Fas ligation.

Alkaloids and flavonoids from peanut skins

Separation of the water-soluble fraction of peanut skins led to the isolation of 8 flavonoids and two novel indole alkaloids. Two new flavonoid glycosides have been identified as isorhamnetin 3-O-[2-O-beta-glucopyranosyl-6-O-alpha-rhamnopyranosyl]- beta-glucopyranoside and 3',5,7-trihydroxyisoflavone-4'-methoxy-3'-O-beta-glucopyranoside. Two alkaloids are 2-methoxyl-3-(3-indolyl)-propionic acid and 2-hydroxyl-3-[3-(1-N-methyl)-indolyl]-propionic acid. These isolated flavonoids were evaluated for their free radical scavenging activity and protein glycation inhibitory effects.

Protective role of ATP-sensitive potassium channels in hypoxia-induced generalized seizure

Adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channels are activated by various metabolic stresses, including hypoxia. The substantia nigra pars reticulata (SNr), the area with the highest expression of K(ATP) channels in the brain, plays a pivotal role in the control of seizures. Mutant mice lacking the Kir6.2 subunit of K(ATP) channels [knockout (KO) mice] were susceptible to generalized seizures after brief hypoxia. In normal mice, SNr neuron activity was inactivated during hypoxia by the opening of the postsynaptic K(ATP) channels, whereas in KO mice, the activity of these neurons was enhanced. K(ATP) channels exert a depressant effect on SNr neuronal activity during hypoxia and may be involved in the nigral protection mechanism against generalized seizures.

Bone induction by porous glass ceramic made from Bioglass (45S5)

Porous glass ceramic, which was prepared from Bioglass powder (45S5, U.S. Biomaterials) by foaming with diluted H(2)O(2) solution and sintering at 1000 degrees C for 2 h, was implanted as cylinders (5 mm in diameter and 6 mm in length) in thigh muscles of dogs for 3 months. Histological observation was made on thin un-decalcified sections. Bone formation was histologically found in pores of all implants (X16) retrieved from 16 dogs. The bone tissue was also identified with backscattered scanning electron microscopy observation (BSE) and energy dispersive X-ray microanalysis (EDX). This is the first report of bone induction in soft tissues of animals by glass ceramic that has long been recognized as a bioactive (osteoconductive) biomaterial. The present results justify the impetus to investigate the osteoinductivity of calcium phosphate-based biomaterials, to study the mechanism of bone induction (osteoinduction) by calcium phosphate-based biomaterials, to develop osteoinductive calcium phosphate-based biomaterials, and to examine the relation between osteoinduction and osteoconduction.

Inhibition of host transcription by vesicular stomatitis virus involves a novel mechanism that is independent of phosphorylation of TATA-binding protein (TBP) or association of TBP with TBP-associated factor subunits

The matrix (M) protein of vesicular stomatitis virus (VSV) is a potent inhibitor in vivo of transcription by all three host RNA polymerases (RNAP). In the case of host RNA polymerase II (RNAPII), the inhibition is due to lack of activity of the TATA-binding protein (TBP), which is a subunit of the basal transcription factor TFIID. Despite the potency of M protein-induced inhibition in vivo, experiments presented here show that M protein cannot directly inactivate TFIID in vitro. Addition of M protein to nuclear extracts from uninfected cells did not inhibit transcription activity, indicating that the inhibition is indirect and is mediated through host factors. The host factors that are known to regulate TBP activity include phosphorylation by host kinases and association with different TBP-associated factor (TAF) subunits. However, TBP in VSV-infected cells was found to be assembled normally with its TAF subunits, as shown by ion exchange high-pressure liquid chromatography and sedimentation velocity analysis. A normal pattern of phosphorylation of TBP in VSV-infected cells was also observed by pH gradient gel electrophoresis. Collectively, these data indicate that M protein inactivates TBP activity in RNAPII-dependent transcription by a novel mechanism, since the known mechanisms for regulating TBP activity cannot account for the inhibition.

[Study on endothelial dysfunction and platelet activation in elderly hypertensive patients complicated with cerebral infarction]

OBJECTIVE

The aim of this paper was to investigate endothelial dysfunction, platelet activation, and inflammation in elderly hypertensive patients and those complicated with cerebral infarction.

METHODS

Twenty-eight elderly hypertensive patients complicated with cerebral infarction(within 72 hours after onset of neurological symptoms), thirty-one Stage I-II elderly hypertensive patients and twenty-eight elderly healthy individuals were selected as subjects. Their plasma concentrations of von Willebrand factor(vWF), alpha granule membrane protein-140(GMP-140), and serum concentrations of C-reaction protein(CRP) were examined.

RESULTS

Elderly hypertensive patients complicated with cerebral infarction had significantly higher plasma vWF, GMP-140, and serum CRP than elderly hypertensive patients and elderly healthy individuals. Plasma vWF and GMP-140 were higher in elderly hypertensive patients than elderly healthy individuals, whereas serum CRP was increased slightly and there was no significant difference between elderly hypertensive patients and elderly healthy individuals.

CONCLUSION

This study suggests that elderly hypertensive patients complicated with cerebral infarction have obvious endothelial dysfunction, platelet activation, and inflammatory change. Stage I-II elderly hypertensive patients have obvious endothelial dysfunction and platelet activation as well.

Low-density lipoprotein receptor-related protein-5 binds to Axin and regulates the canonical Wnt signaling pathway

To understand how the Wnt coreceptor LRP-5 is involved in transducing the canonical Wnt signals, we identified Axin as a protein that interacts with the intracellular domain of LRP-5. LRP-5, when expressed in fibroblast cells, showed no effect on the canonical Wnt signaling pathway by itself, but acted synergistically with Wnt. In contrast, LRP-5 mutants lacking the extracellular domain functioned as constitutively active forms that bind Axin and that induce LEF-1 activation by destabilizing Axin and stabilizing beta-catenin. Addition of Wnt caused the translocation of Axin to the membrane and enhanced the interaction between Axin and LRP-5. In addition, the LRP-5 sequences involved in interactions with Axin are required for LEF-1 activation. Thus, we conclude that the binding of Axin to LRP-5 is an important part of the Wnt signal transduction pathway.

Purification, refolding of hybrid hIFNgamma-kringle 5 expressed in Escherichia coli

The DNA sequence coding for plasminogen kringle 5 (pK5), an inhibitor of angiogenesis, was fused with that coding for interferon gamma and over-produced in the form of inactive inclusion bodies in E. coli. The amount of fusion protein was about 40% of total protein produced. The fusion protein contained in the inclusion bodies was solubilized in 8 M urea and purified by anion-exchange chromatography. We employed the orthogonal experimental design L16(4(5)) (5 factors, 4 levels, 16 experiments) procedure for researching the influence of denaturant, aggregation suppressor L-arginine, NaCl, pH, and glycine on the refolding procedure. Our results suggest that the presence of appropriate L-arginine, NaCl, and denaturant in the refolding buffer inhibits the aggregation of the fusion protein and increases the yield of renatured protein with biological activity. The refolded fusion protein, gammaIFN/pk5, has in vitro anti-endothelial cell proliferation activity.

Primary studies on heroin abuse and injury induced by oxidation and lipoperoxidation

OBJECTIVE

To further reveal serious risks of heroin abuse to human body and clarify grave injuries of oxidation, peroxidation and lipoperoxidation induced by nitric oxide and other free radicals to heroin abusers.

METHODS

Determined and compared plasma levels of nitric oxide (P-NO), vitamin C (P-VC), vitamin E (P-VE), beta-carotene (P-beta-CAR), lipoperoxides (P-LPO) and erythrocyte activities of superoxide dismutase (E-SOD), catalase (E-CAT), glutathione peroxidase (E-GSH-Px) and erythrocyte level of lipoperoxides (E-LPO) in 137 cases of heroin abusers (HAs) and 100 cases of healthy volunteers (HVs), used linear regression and correlation, stepwise regression and correlation to analyze correlation among heroin-abusing-duration (HAD), daily-heroin-abusing-quantity (DHAQ) with above determination values in the HAs.

RESULTS

Compared with the above average values in the HVs group, the average values of P-NO, P-LPO, E-LPO in the HAs group were significantly increased (P < 0.0001), the average values of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT and E-GSH-Px were significantly decreased (P < 0.0001); the analysis of linear regression and correlation showed that with ascending of the HAD and DHAQ in the HAs, the values of P-NO, P-LPO, E-LPO were gradually increased (P < 0.0001), the values of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT, E-GSH-Px were gradually decreased (P < 0.0001); the analysis of stepwise regression and correlation suggested that the correlation among the HAD, DHAQ with the values of P-NO, P-VC, P-VE was the closest.

CONCLUSION

The balance between oxidation and antioxidation in the HAs was seriously destroyed, and the injuries induced by nitric oxide and other free radicals, oxidation, peroxidation and lipoperoxidation reactions to the body of HAs gravely exacerbated. In the abstaining from heroin dependence, therefore, it should consider that sufficient quantum antioxidants such as VC, VE and beta-CAR are dosed to the HAs so as to abate the injuries to their bodies.

[A permanent implantable pulsatile impeller heart with a specially devised needle bearing]

The author's implantable pulsatile impeller pump can assist the circulation of the calves for several months. The termination of the experiments was related to wear of the mechanical bearing, which resulted in vibration of the rotor and pump failure. It seemed as if the experiments could have lasted indefinitely if the bearing had not failed. To solve the problem of bearing wear, a specially devised rolling bearing was investigated and applied to the impeller pump. Its service life is more than 10 years due to the wear-proof roller made of ultra-highmolecular weight polythene. This newly devised impeller heart promises to have long-term and permanent applications. Compared with the magnetic bearing, the rolling bearing has the advantages of simpler construction and control, no consumption of energy, and better reliability.

[Edge-detection and its application in medical image processing]

Edge-detection is all the time a major problem in the computer early vision, and it plays an important role in image processing. This paper reviews classical and new methods of edge-detection and discusses its application in medical image processing.

Aminopeptidase A: a nephritogenic target antigen of nephrotoxic serum

BACKGROUND

We investigated potential targets of antibody-mediated glomerular injury induced with a noncomplement binding fraction of sheep anti-rat nephrotoxic serum (NTS). This model is characterized by severe complement- and leukocyte-independent proteinuria within 24 hours of NTS injection into rats.

METHODS

NTS-reactive glomerular cell and matrix proteins were identified by immunoprecipitation, Western blot analysis, protein sequencing, cDNA library screening, and enzyme-linked immunosorbent assay. Proteinuria was measured in rats injected with NTS from which reactivity against type IV collagen had been removed by immunoadsorption, and antibodies were eluted from the glomeruli of proteinuric rats that had been injected with unabsorbed NTS. Having identified aminopeptidase A (APA) as a major target of NTS, we studied the effect of NTS and anti-APA on mouse glomerular epithelial cells in culture.

RESULTS

NTS identified several podocyte and matrix proteins; however, APA was the only cell surface protein reactive with antibodies eluted from the glomeruli of rats injected with NTS. Although the eluate also contained reactivity to the noncollagenous domains of alpha1 and alpha3 chains of type IV collagen, immunodepletion of these antibodies did not diminish the ability of NTS to cause proteinuria. We also documented the surface expression of APA on mouse glomerular epithelial cells in culture, and found that NTS and specific anti-APA antibodies induce a time- and temperature-dependent redistribution of the antigen.

CONCLUSIONS

APA, a type II integral membrane metallopeptidase, is a major target of NTS in vivo and is known to be present on the surface of podocytes. NTS-induced proteinuria is independent of reactivity to known nephritogenic matrix proteins. These findings, in combination with previous studies showing that monoclonal anti-APA antibodies induce severe proteinuria in mice, suggest that anti-APA antibodies are responsible for complement-independent proteinuria in this model.

Synthesis and bioactivity of 2,4-diacyl analogues of paclitaxel

The 2,4-diacyl paclitaxel analogues 8a-8r were prepared from paclitaxel by acylation of 4-deacetyl-2-debenzoylpaclitaxel 1,2-carbonate (3) followed either by hydrolysis of the carbonate and acylation or by direct treatment of the carbonate with an aryllithium. Some of the resulting derivatives showed significantly improved tubulin assembly activity and cytotoxicity as compared with paclitaxel; in some cases this improvement was especially significant for paclitaxel-resistant cell lines.