Structure-activity relationships study at the 3'-N position of paclitaxel. Part 2: synthesis and biological evaluation of 3'-N-thiourea- and 3'-N-thiocarbamate-bearing paclitaxel analogues

The syntheses and preliminary biological evaluation of 3'-N-thiocarbamate- and 3'-N-thiourea-bearing paclitaxel analogues, 4a-f and 5a-e, are described. 3'-N-thiocarbamates 4a-e were found to be more potent than paclitaxel in both the tubulin polymerization assay and the in vitro cytotoxicity assay. Several derivatives of this class such as 4c, 4d, and 4e also exhibited some in vivo activity.

[Change of plasma cellular fibronectin values in hypertension disorders of pregnancy]

OBJECTIVE

To investigate change of plasma values of cellular fibronectin (cFN) in pregnant women with hypertension diseases.

METHODS

One hundred and twelve pregnant women were assigned into five groups according to definition of hypertension diseases in pregnancy published by the National Working Group on Hypertension. The values of plasma cFN were measured with enzyme-link immunosorbent assay (ELISA). Statistical tests were performed with Variance Analysis (Scheff's post-hoc).

RESULTS

Plasma cFN values in women of preeclamptic group (12.25 +/- 4.00) mg/L and superimposed preeclamptic group (11.33 +/- 3.74) mg/L were both significantly higher than those of normal group (5.06 +/- 1.33) mg/L (P < 0.01). However, cFN values were not statistically different between women of chronic hypertension or transient hypertension and of normal women (P > 0.05).

CONCLUSION

The clinical detection of plasma cFN values appears to be useful in differentiating various hypertension diseases of pregnancy and in selection of relevant treatment regimen.

Intracerebral injection of autologous whole blood in rats: time course of inflammation and cell death

Intracerebral hemorrhage is associated with stroke and head trauma. The purpose of this study was to study brain inflammation and cell death in adult rats 1 h to 4 weeks after injection of blood into the striatum. Terminal dUTP nick-end-labeling positive dying cells were evident 4 h to 4 weeks post-hemorrhage. Neutrophil infiltration was brief and peaked at 48 h. CD8a immunoreactive lymphocytes, possibly natural killer cells, became apparent at 48 h and persisted for 1 week. Microglial reaction was evident at 4 h and persisted for 4 weeks. We conclude that extravascular blood causes a mixed inflammatory cell reaction in brains that is maximal from 48-72 h following hemorrhage. This is associated with death of brain cells over a prolonged period of at least 4 weeks.

Hirulog-1 reduces expression of platelet-derived growth factor in neointima of rat carotid artery induced by balloon catheter injury

Vascular restenosis is one of the major concerns for the treatment of atherosclerotic cardiovascular diseases using therapeutic vascular procedures. Hirulog-1, a synthetic thrombin inhibitor, effectively reduced ischemic events in coronary heart disease patients and caused less hemorrhagic complications compared to heparin. Thrombin stimulated the expression of platelet-derived growth factor (PDGF) in vascular cells. PDGF receptor blockers reduced angioplasty-induced restenosis in the swine model. The present study examined the effects of hirulog-1 on vascular stenosis, platelet deposition and the expression of PDGF in rat carotid arteries injured by balloon catheter. Multiple intravenous infusions of hirulog-1 (1 mg/kg/h for 4 h for 6 times), but not bolus injection or 1-2 times of infusion, reduced neointima/media ratio by 50% in balloon-injured carotid arteries compared to injured animals receiving saline alone. Activated partial thromboplastin time in hirulog-1-treated rats was significantly prolonged compared to saline controls but shorter than that in animals receiving heparin (50 U/kg/h). One of heparin-treated rat, but none of hirulog-1-treated, died from bleeding complication. Hirulog-1 injection transiently reduced platelet deposition on denuded intima visualized by scanning electron microscopy. Abundance of PDGF in neointima of injured carotid arteries detected by immunohistochemistry was significantly decreased following infusions of hirulog-1. The results suggest that balloon catheter injury induced neointima formation and the overexpression of PDGF in the neointima of rat carotid artery may be effectively suppressed by infusions with hirulog-1, a thrombin-specific inhibitor.

[Study on biocompatibility of skin reproductive membrane]

OBJECTIVE

To study the biocompatibility of skin reproductive membrane.

METHODS

According to ISO's standards, the extractions of the skin reproductive membrane were prepared, and the acute systematic toxicity test, primary skin irritant test, cytotoxicity test, gene expression of type I collagen and fibronectin were detected to evaluate the biocompatibility of skin reproductive membrane.

RESULTS

All of those tests showed negative results.

CONCLUSION

The skin reproductive membrane has excellent biocompatibility in the level of the systematic, cellular and molecular biology.

[Stress-adaptation of bone]

Loading mechanotransduction sensors on the membrane of bone cells or osteoblasts can improve bone mechanisms and influence second messages, growth factors, bone matrix and oncogenes. The response of bone to stree is preportion to the magmititude of the stress. Stress-adaptation of bone is related with the magnititude, perporties, frequency time of stress.

[Effect of in vitro interferon on bone marrow megakaryocyte in patients with idiopathic thrombocytopenic purpura]

The effect of rIFN alpha-2a on the megakaryocyte colony growth and maturation was observed in 33 patients with idiopathic thrombocytopenic purpura (CITP) in vitro by plasma clot cultures and by GP III a McAb and ABC kit. Twenty five healthy persons were in the control group. The results showed that the number of colony formation units of megakaryocyte in the patients was similar to that in the controls, but the diameter and area levels of megakaryocyte in the patients were lower. The ratio of inhibition of rIFN alpha-2a on megakaryocyte progenitors colony growth was significantly lower in the patients and was lowest in the group with increasing number of megakaryocytes on bone marrow smear. The rIFN alpha-2a had no effect on promoting the megakaryocyte maturation. Since this study has indicated that the inhibition of rIFN alpha-2a on colony formation unit of megakaryocyte is slight in CITP, interferon therapy should be a suitable prescription for the CITP patients who have an increasing number of megakaryocyte on bone marrow smear.

[A comparative study on cytocompatibility of medical PVA and intelligent PVA-g-NIPAAm hydrogels]

"Intelligent" Polymers which resonse with large property changes to small physical or chemical stimuli are attracting more and more attention in the field of medical science. One trend in the area is to modify some conventional medical polymers to form intelligent biomaterials. This investigation was designed to evaluate and compare in vitro cytocompatibility of PVA hydrogel, which could be used as a kind of solid support with good biomcompatibility, and PVA-g-NIPAAm, which was produced by irradiation grafting of NIPAAm onto the said PVA hydrogel support. Cytotoxicity test was carried out with a modified Cell Relative Growth Rate test (RGR test). On the day 2, day 4 and day 7, the RGRs of the PVA hydrogel were 82%, 90% and 102% respectively while the RGRs of the PVA-g-NIPAAm were 77%, 86% and 100%. The grades of the cytotoxicity of the PVA and PVA-g-NIPAAm hydrogels were 0, so they had no cytotoxicity as judged by our tests. After 24 hours, cells in direct contact with the two kinds of samples were observed morphologically through the Olympus inverted microscope and had a normal development. The conclusion suggests that irradiation grafting is a good way to modify conventional medical polymers to produce intelligent biomaterials.

Influence of percentage of osseointegration on stress distribution around dental implants

OBJECTIVE

Stress around implants may lead to bone resorption and loss of the implant. The present study examined the influence of percentage of osseointegration at the implant-bone interface on the transmission of occlusal forces for endosseous dental implants.

METHODS

The three-dimensional finite element method used in the study was built from data obtained from slices of dental computed tomography scans. The study modeled a 3.75 x 10-mm cylindric implant placed in an edentulous mandible. Varying the elastic parameters assigned to the implant-bone interface, a load of 35 N was applied at the occlusal surface of the restoration at the vertical axis of the implant. Maximum principal stress, minimum principal stress and Von Mises stress were calculated.

RESULTS AND CONCLUSIONS

The most extreme stresses in the bone were always located around the neck of the implant. Those stresses in the implant-tissue interface decreased in inverse proportion to the increase in percentage of osseointegration. These results indicate the value of osseointegration in the aspect of mechanics.

[Analysis of trace Pd in marine deposit samples using laser-excited atomic fluorescence spectrometry]

Laser-excited atomic fluorescence spectrometry and its experimental set-up are introduced in this paper. Using this spectrometer, Pd contents in 36 marine deposit samples of the East-sea continental shelf were analyzed. The results show that the detection limit and the precision of this spectrometer are 50 pg/mL and 6% respectively, and the measurements of Pd in marine deposit samples are reliable.

Morphological study by an 'in vivo cryotechnique' of the shape of erythrocytes circulating in large blood vessels

Changes in the shape of erythrocytes circulating in large blood vessels of mice were examined by our 'in vivo cryotechnique'. The abdominal aorta and inferior vena cava (IVC) were cut vertically with a precooled knife and simultaneously an isopentane-propane mixture (-193 degrees C) was poured over them for freezing. They were freeze-substituted in acetone containing 2% osmium tetroxide. Some specimens were embedded in Quetol-812, and thick or ultrathin sections were examined by light or transmission electron microscopy. Serial ultrathin sections were used to reconstruct 3-dimensional images of native erythrocytes. Others were transferred into t-butyl alcohol and freeze-dried for scanning electron microscopy. The tissue surfaces were sufficiently frozen to prevent large ice crystal formation, and erythrocyte shapes were also preserved. The shapes of circulating erythrocytes appeared to be varied in the abdominal aorta but typical biconcave discoid shapes were rarely observed. Conversely, erythrocytes were approximately biconcave discoid in shape in the IVC. Our in vivo cryotechnique was useful for clarifying the in vivo morphology of erythrocytes circulating in large blood vessels.

[The research on GH composite material of artificial bone implant in animal]

OBJECTIVE:To improve modeling different complex forms ability of pure hydroxyapatite.METHODS: Medicial gelatin and hydroxyapatite were compounded to form GH composite artifical bone.It was implanted in the tibial bone of six adult female New Zealand white rabbits.The rabbits were sacrificed at week 2, 6 and 12 respectively after operation,The bone repairing ability was assessed by histology observation.RESULTS:It connect with bone directly without inflammatory reactions with the muscle tissue.CONCLUSION:It's an ideal replacement material for bone.

[Study on the characteristics of brucellosis on the Baicaopo Pasture]

To study the current situation and characteristics of brucellosis on Baicaopo Pasture, a sero-epidemiological survey was conducted among local people, animals together with nearby county livestocks from Breed-improvement Stations, Bingdi township and Rekejue township which are far away from the pasture. The results showed that the infection rates of brucellosis in humans and yaks on the Baieaopo Pasture were 31.03% and 47.19% respectively, apparent higher than those in other places. There were more infected cases among local veterinarians and herdsmen than among other jobs. Young adults seemed to be at most risk.

[Stess analysis of conical telescope denture using on the prosthodontic treatment for basic teeth combined periodontal diseases]

OBJECTIVE:Periodontal splints were made both on patients with peridontal absorption of three different degrees and on normal situation respectively followed by finite element calculation.The result sugree that the stesses of the supporting tissues redistributed during mastication in accordance with different degrees of periodontal absorption.The more obvious of the pcriodontal absorption is the more stress value of the periodontal supporting tissue decrease,while those of the subbasal supporting tissues increase.

Oblique proton chemical shift imaging for the presurgical localization of mesial temporal epilepsy

Precise localization of the epileptogenic zone in patients suffering from mesial temporal lobe epilepsies is a prerequisite for surgery. For this purpose, a scheme for selecting the volume of interest in an oblique plane covering the head, body, and tail of the hippocampal formation (HF) was implemented in a water-suppressed proton chemical shift imaging (CSI) acquisition. This approach, evaluated by consecutively acquired CSI spectra of both temporal lobes, demonstrates that it can potentially be a routine technique for clinical diagnosis. Since the method produces localized spectral detail of the HF, it facilitates a convenient comparison of CSI lateralization to that assessed by HF atrophy (due to sclerosis) using the MRI-volumetry technique.

[Three dimensional FEM analysis of stress distribution around dental implants to estimate the influence of the length]

The effect of the length of implants on stress distribution is one of the important subjects in implantology.In this study,Three dimensional finite element methods model was constructed by dental CT images,The purpose of this study was to evaluate the stress distribution in bone adjacent to an implant after application of loading in horizontal,oblique and vertical direction.It was show that the highest stress occured at the cervical bone margin adjacent to the implant only 10% decrease in inverse two times increase in implant length,and correlated little to the implant length,therefore,it was unnecessary to emphasize the length of the implants in clinic.

[Study on the compatibility of slip casting aluminous ceramic crowns]

One of the key factors for a good slip casting aluminous ceramic crown is good compatibility between its core material and the veneering porcelain.The chemical and thermal compatibility of two slip casting aluminous ceramic crown systems(In-Ceram and GI-I) were investigated by means of SEM and EDAX,thermal shock tests were also performed to evaluate the crazing resistance.The results showed: the crazing resistance of In-Ceram was 158 degrees centigrade,and that of GI-I was degrees centigrade;there existed tightly bonded interfaces between the slip casting aluminous ceramic cores and the veneering porcelains in both of the two systems,where ion transferences were found.The results also suggested good compatibility of the two slip casting aluminous ceramic crown systems.

[Stress research on support tissues of Buffer-typed conical telescopic removable denture]

In order to explore the biomechanical physiology of Buffer-typed conical telescopic removable denture restoring defected dentition with a preponderance of teeth lost and only a few remained,the authors have studied the stress distribution of the periodontal support tissue of abutments and subbasal support tissue when subjected to forced transfered from removable denture of both Buffer-typed and non Buffer-typed telescopic retainers.The results suggest that occlusal forces can be redistribute through dentures with buffer typed conical telescopic retainers which decrease forces sustained by abutments and increase the ones by subbasal support tissues thus avoiding trauma of abutments while having certain degree if physiological stimuli.We can also decrease the forces transfered to subbasal support tissues by expanding basal areas,so to alleviate the absorption of alveolar ridges.This resut is in accordance with clinical effects.

[Development of a SIRI-TOFMS and the application research progress]

The only one set of Sputter Initiated Resonance Ionization-Time of Flight Mass Spectrometer (SIRI-TOFMS) in China was designed and developed. A liquid gallium ion source with micron level diameter of beam, frame-style piezoeletric ceramic sub-micron sample manipulator, a secondary electron imaging system and a computer controlled precise targeting system as well as a real colour big screen image displaying system were added so as to improve its microanalysis capability. By means of this apparatus, trace analysis of Au in minerals and Cu in standard steel samples were carried out. The detection limit of them is 40ng/ and microg/g level, respectively. Aside from the above detections, other preliminary researches ere also performed.

Progress in studies on the overwintering of the mosquito Culex tritaeniorhynchus

A detailed review is presented of half a century's research in Japan, Korea and the temperate zone of China on the overwintering of Culex tritaeniorhynchus, the main vector of Japanese encephalitis. The evidence indicates that in the temperate zone, two types of overwintering strategy can be distinguished in Cx. tritaeniorhynchus, ie survival by adults in situ in a dormant state, or migration by individuals which are in reproductive diapause. The authors contend that the former strategy is not very effective, and individuals which overwinter in this way do not constitute the main source of the next season's mosquito populations. On the contrary, new mosquito populations seem to be established by groups of adults which appear suddenly, early in the year, and which are probably windborne migrants from the south. It is concluded that further research into the mode of overwintering of Cx. tritaeniorhynchus should focus on the effective source of the populations which appear in temperate areas in early spring, and that efforts should be made to increase our understanding of the migration patterns of this species.

Postictal alteration of sodium content and apparent diffusion coefficient in epileptic rat brain induced by kainic acid

PURPOSE

We studied temporal changes of brain sodium and apparent diffusion coefficient (ADC) in a temporal lobe epilepsy (TLE) rat model using kainic acid (KA).

METHODS

In situ three-dimensional 23Na magnetic resonance imaging (MRI) and proton diffusion-weighted imaging (DWI) were used. KA at a dose of 10 mg/kg body weight and 12 adult Sprague Dawley rats weighing 228-318 g (268 +/- 25 g) were used.

RESULTS

Twenty-four hours after KA injection, magnetic resonance (MR) visible sodium levels increased in both the pyriform cortex (+90%) and amygdala (+68%) and increased insignificantly in the hippocampus (+18%) and caudate-putamen (12%). The ADC in the pyriform cortex showed a -9% decrease at 5 h postictally, reaching -30% at 24 h, whereas in the amygdala decreases were -8 and -26% respectively. A significant decrease in ADC (-7%) in the hippocampus was also observed 24 h postically. Seven days later, sodium increases persisted, whereas ADC returned to normal level.

CONCLUSIONS

The increase in MR visible sodium, associated with the decrease in ADC is consistent with the hypothesis that sequential seizures caused an increase in sodium influx and perturbation of membrane ion homeostasis, which eventually evolved into an irreversible phase of cellular edema, with increased MR visible intracellular sodium and decreased ADC. Return of ADC to near-control level and persistent high sodium level at 7 days may be explained by the increase in extracellular space and tissue necrosis.