Bibliometric analysis on retinoblastoma literatures in PubMed during 1929 to 2010

AIM

To determine the growth rule and tendency of retinoblastoma (Rb) literature, and to provide the basis for research of diagnosis, treatment and on Rb.

METHODS

Bibliometric analyses were carried out on Rb literatures which contain the descriptors of Rb in their titles or texts from 1929 to 2010 in PubMed database (www.ncbi.nlm.nih.gov/Pubmed). The biomedical journals referring to Rb by using bibliometric indicators were calculated. The principal bibliometric indicators, i.e., Price's and Bradford's laws to the increase or distribution of scientific literature, the participation index of languages and the journals were applied. By means of manual coding, Rb documents were classified according to documents studied and to statistical analysis.

RESULTS

During 1929-2010, there were 16162 literatures in the PubMed database including the word Rb. According to the literature type, it includes Review (n=2026), Randomized Controlled Trial (n=7), Practice guideline (n=3), meta-analysis (n=4), letter (n=215), editorial (n=98), clinical trial (n=115) and others (n=13694). By the statistical analysis, its equation is near power index (y=3.0477x(2.6088), R(2)=0.9666). From 1929 to 2010, Rb literatures in English were primarily dominant (90.71%) and the amount of the literature in Chinese ranked the fourth (1.37%). By searching PubMed, 1420(8.8%) literatures covered were from 41 of 48 ophthalmological, and 406 (2.5%) literatures from 44 of 86 pediatrics journals that correlated with retinoblastoma (SCI-indexed). The data showed that the literatures of Rb were gradually increasing year by year and were approximate near power index during 1929-2010, and the document publishes published mainly in ophthalmological journals, and in English (90.71%), and showing that the study on Rb is a popular subject in the last half century.

CONCLUSION

The literatures of Rb are gradually increasing, mainly English in ophthalmologic journals.

Post-injury administration of minocycline: an effective treatment for nerve-injury induced neuropathic pain

Neuropathic pain is an intractable clinical problem, affecting millions of people worldwide. Preemptive administration of minocycline has been confirmed useful for treating neuropathic pain by inhibiting spinal microglia activation and consequently lowering proinflammatory cytokine expression. However, most patients with neuropathic pain have no chance to receive preemptive treatment and it remains unclear whether there is a therapeutic time window for post treatment with minocycline. The present study is to confirm the effect and the therapeutic time window of intrathecal minocycline on spinal nerve ligation (SNL)-induced neuropathic pain after lesion. Behavioral test and immunohistochemistry are utilized to determine the variation of mechanical allodynia and microglia phosphorylated-p38 (p-p38) expression respectively after intrathecal minocycline. Results showed that post-injury intrathecal minocycline attenuated mechanical allodynia effectively together with inhibiting spinal microglia p-p38 expression on post operative day (POD) 1, POD 3 and POD 7. Additionally, results from POD 10 and POD 21 showed that intrathecal minocycline suppressed spinal microglia p-p38 expression but without any effects on reversing mechanical allodynia. It is concluded that post-injury intrathecal minocycline is an effective therapeutic intervention for treating SNL-induced neuropathic pain by inhibiting spinal microglia activation. Accordingly, there is indeed a therapeutic time window for post-injury intrathecal minocycline, which is the initiation stage of neuropathic pain development.

Ketamine depresses toll-like receptor 3 signaling in spinal microglia in a rat model of neuropathic pain

Reports suggest that microglia play a key role in spinal nerve ligation (SNL)-induced neuropathic pain, and toll-like receptor 3 (TLR3) has a substantial role in the activation of spinal microglia and the development of tactile allodynia after nerve injury. In addition, ketamine application could suppress microglial activation in vitro, and ketamine could inhibit proinflammatory gene expression possibly by suppressing TLR-mediated signal transduction. Therefore, the present study was designed to disclose whether intrathecal ketamine could suppress SNL-induced spinal microglial activation and exert some antiallodynic effects on neuropathic pain by suppressing TLR3 activation. Behavioral results showed that intrathecal ketamine attenuated SNL-induced mechanical allodynia, as well as spinal microglial activation, in a dose-dependent manner. Furthermore, Western blot analysis displayed that ketamine application downregulated SNL-induced phosphorylated-p38 (p-p38) expression, which was specifically expressed in spinal microglia but not in astrocytes or neurons. Besides, ketamine could reverse TLR3 agonist (polyinosine-polycytidylic acid)-induced mechanical allodynia and spinal microglia activation. It was concluded that intrathecal ketamine depresses TLR3-induced spinal microglial p-p38 mitogen-activated protein kinase pathway activation after SNL, probably contributing to the antiallodynic effect of ketamine on SNL-induced neuropathic pain.

Inhibition of spinal astrocytic c-Jun N-terminal kinase (JNK) activation correlates with the analgesic effects of ketamine in neuropathic pain

Background

We have previously reported that inhibition of astrocytic activation contributes to the analgesic effects of intrathecal ketamine on spinal nerve ligation (SNL)-induced neuropathic pain. However, the underlying mechanisms are still unclear. c-Jun N-terminal kinase (JNK), a member of mitogen-activated protein kinase (MAPK) family, has been reported to be critical for spinal astrocytic activation and neuropathic pain development after SNL. Ketamine can decrease lipopolysaccharide (LPS)-induced phosphorylated JNK (pJNK) expression and could thus exert its anti-inflammatory effect. We hypothesized that inhibition of astrocytic JNK activation might be involved in the suppressive effect of ketamine on SNL-induced spinal astrocytic activation.

Methods

Immunofluorescence histochemical staining was used to detect SNL-induced spinal pJNK expression and localization. The effects of ketamine on SNL-induced mechanical allodynia were confirmed by behavioral testing. Immunofluorescence histochemistry and Western blot were used to quantify the SNL-induced spinal pJNK expression after ketamine administration.

Results

The present study showed that SNL induced ipsilateral pJNK up-regulation in astrocytes but not microglia or neurons within the spinal dorsal horn. Intrathecal ketamine relieved SNL-induced mechanical allodynia without interfering with motor performance. Additionally, intrathecal administration of ketamine attenuated SNL-induced spinal astrocytic JNK activation in a dose-dependent manner, but not JNK protein expression.

Conclusions

The present results suggest that inhibition of JNK activation may be involved in the suppressive effects of ketamine on SNL-induced spinal astrocyte activation. Therefore, inhibition of spinal JNK activation may be involved in the analgesic effects of ketamine on SNL-induced neuropathic pain.

Effects of propofol versus urapidil on perioperative hemodynamics and intraocular pressure during anesthesia and extubation in ophthalmic patients

AIM

To compare the effect of propofol versus urapidil on hemodynamics and intraocular pressure during anesthesia and extubation for ophthalmic patients.

METHODS

Eighty-two surgical patients (Class: ASA I-II) were randomly assigned to propofol (n=41) and urapidil groups (n=41). Their gender, age, body mass, operation time and dosage of anesthetics had no significant difference between the two groups (P>0.05). The patients of propofol and urapidil groups were given propofol (1.5mg/kg) and urapidil (2.5mg/kg) respectively; and two drugs were all diluted with normal saline to 8mL. Then the drugs were given to patients by slow intravenous injection. After treatment, the patients were conducted immediate suction, tracheal extubation, and then patients wore oxygen masks for 10 minutes. By double-blind methods, before the induction medication, at the suction, and 5, 10 minutes after the extubation, we recorded the systolic and diastolic blood pressure (BP), heart rate (HR), pH, PaO(2), PaCO(2), SaO(2) and intraocular pressure (IOP) respectively. The complete recovery time of the patients with restlessness (on the command they could open eyes and shaking hands) was also recorded during the extubation. The data were analyzed by using a professional SPSS 15.0 statistical software.

RESULTS

The incidence of cough, restlessness and glossocoma was significantly lower in the propofol group than that in the urapidil group after extubation (P<0.05). There were no episodes of hypotension, laryngospasm, or severe respiratory depression. There was no statistical difference in recovery time between two groups (P>0.05). In propofol group, the BP and HR during extubation and thereafter had no significant difference compared with those before induction, while they were significantly lower than those before giving propofol (P<0.05), and had significant difference compared with those in urapidil group (P<0.05). Compared to preinduction, the BP of urapidil group showed no obvious increase during aspiration and extubation. The HR of urapidil group had little changes after being given urapidil, and it was obviously increased compared with that before induction. The stimulation of aspiration and extubation caused less cough and agitation in propofol group than that in urapidil group (P<0.05). The IOP of propofol group showed no obvious increase during extubation compared with that in preinduction, while in the urpidil group, extubation caused IOP significantly increased (P<0.05). The changes in these indicators between the two groups had no significant difference (P>0.05).

CONCLUSION

Compared to urapidil, propofol is superior for preventing the cardiovascular and stress responses and IOP increases during emergence and extubation for the ophthalmic patients. Moreover, it has no effects on patient's recovery.

Combining ketamine with astrocytic inhibitor as a potential analgesic strategy for neuropathic pain ketamine, astrocytic inhibitor and pain

BACKGROUND

Neuropathic pain is an intractable clinical problem. Intrathecal ketamine, a noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist, is reported to be useful for treating neuropathic pain in clinic by inhibiting the activity of spinal neurons. Nevertheless, emerging studies have disclosed that spinal astrocytes played a critical role in the initiation and maintenance of neuropathic pain. However, the present clinical therapeutics is still just concerning about neuronal participation. Therefore, the present study is to validate the coadministration effects of a neuronal noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine and astrocytic cytotoxin L-α-aminoadipate (LAA) on spinal nerve ligation (SNL)-induced neuropathic pain.

RESULTS

Intrathecal ketamine (10, 100, 1000 μg/kg) or LAA (10, 50, 100 nmol) alleviated SNL-induced mechanical allodynia in a dose-dependent manner respectively. Phosphorylated NR1 (pNR1) or glial fibrillary acidic protein (GFAP) expression was down-regulated by intrathecal ketamine (100, 1000 μg/kg) or LAA (50, 100 nmol) respectively. The combination of ketamine (100 μg/kg) with LAA (50 nmol) showed superadditive effects on neuropathic pain compared with that of intrathecal administration of either ketamine or LAA alone. Combined administration obviously relieved mechanical allodynia in a quick and stable manner. Moreover, down-regulation of pNR1 and GFAP expression were also enhanced by drugs coadministration.

CONCLUSIONS

These results suggest that combining NMDAR antagonist ketamine with an astrocytic inhibitor or cytotoxin, which is suitable for clinical use once synthesized, might be a potential strategy for clinical management of neuropathic pain.

Study of heat shock response of human umbilical vein endothelial cells (HUVECs) using cDNA microarray

Genetic response of human umbilical vein cells (HUVECs) to heat shock was studied using gene expression analysis. HUVECs were subjected to heat treatment at 44 degrees C and 55 degrees C for 1 h, respectively. Four hours after the treatment, gene expression of the treated cells and control cells (37 degrees C) were profiled using cDNA microarray. Data were analyzed using bioinformatics tools, and the results were verified by real-time quantitative PCR experiment. It has been shown that a large number of genes were regulated indicating global response to heat treatment at the genetic level.

Efficacy of intracarotid propofol infusion and impact of cerebral blood flow alteration

BACKGROUND

Intracarotid propofol infusion was studied in canines as an experimental basis for application of propofol in the Wada test.

METHODS

First, efficacy and side-effects of propofol anaesthesia were studied in eight mongrel dogs that received intracarotid and i.v. propofol infusions for 30 min according to a cross-over design. Auditory evoked potentials were used to guide anaesthesia. Secondly, eight mongrel dogs received intracarotid propofol infusion during both normal and cerebral hyperperfusion states using nicardipine. Haemodynamics and clinical endpoints were compared between the two infusion conditions.

RESULTS

We required 33 (7.6) mg propofol intracarotically vs 113 (17) mg propofol i.v. to achieve an anaesthetic state. The mean arterial pressure (MAP) decreased about 15-27% from the baseline during i.v. infusion. However, no obvious decrease of MAP was observed after intracarotid infusion. Administration of nicardipine increased the blood flow in the internal carotid artery by 17%. Then, the propofol dosage for achieving the anaesthetic effect increased from 7.7 (0.9) mg in the normal control to 11.3 (0.8) mg in the nicardipine group. The onset time of anaesthetic effect was prolonged and the recovery time was shortened during intracarotid infusion during cerebral hyperperfusion.

CONCLUSIONS

Compared with i.v. propofol infusion, intracarotid infusion could reach and maintain the target anaesthetic depth with less dosage and without affecting MAP. In addition, increase of cerebral blood flow requires a higher propofol dose, prolongs onset, and shortens recovery time during intracarotid propofol anaesthesia, indicating that patients with a cerebral hyperperfusion state may need higher dose of anaesthetics during the Wada test.

Extracellular signal-regulated kinases mediate melittin-induced hypersensitivity of spinal neurons to chemical and thermal but not mechanical stimuli

Subcutaneous melittin injection causes central plasticity at the spinal level in wide-dynamic-range (WDR) neurons, which are hypersensitive to various nociceptive stimuli. Previous behavioral studies demonstrated that the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase 1/2(ERK1/2), p38 MAPK, and c-Jun N-terminal kinase are involved in both peripheral and spinal processing of melittin-induced nociception and hypersensitivity. Yet the functional roles of the three MAPKs vary among different stimulus modalities, and must be further studied at the cellular level in vivo. In this report, extracellular single unit recordings were performed to investigate whether activation of ERK1/2 in the primary injury site of melittin is essential to the establishment of a spinally sensitized state. Localized peripheral administration of a single dose of the MEK inhibitor U0126 (1 μg/10 μl) significantly suppressed neuronal hyper-responsiveness to thermal stimulus and chemical (melittin)-induced tonic firing of WDR neurons after full establishment of a spinally sensitized state. However, U0126 failed to affect mechanical hypersensitivity to both noxious and non-noxious stimuli. Melittin-induced enhancement of thermal hypersensitivity was also greatly inhibited by a single dose of capsazepine, a thermal nociceptor (TRPV1) blocker. These results suggest that activation of the ERK signaling pathway in the periphery is likely necessary for maintenance of a spinally sensitized state; activation of ERK1/2 in the primary injury site may regulate TRPV1, leading to dorsal horn hypersensitivity to thermal and chemical stimuli. ERK signaling pathways are not likely to be associated with melittin-induced dorsal horn hypersensitivity to mechanical stimuli.

A new image correction method for live cell atomic force microscopy

During live cell imaging via atomic force microscopy (AFM), the interactions between the AFM probe and the membrane yield distorted cell images. In this work, an image correction method was developed based on the force-distance curve and the modified Hertzian model. The normal loading and lateral forces exerted on the cell membrane by the AFM tip were both accounted for during the scanning. Two assumptions were made in modelling based on the experimental measurements: (1) the lateral force on the endothelial cells was linear to the height; (2) the cell membrane Young's modulus could be derived from the displacement measurement of a normal force curve. Results have shown that the model could be used to recover up to 30% of the actual cell height depending on the loading force. The accuracy of the model was also investigated with respect to the loading force and mechanical property of the cell membrane.

Performance evaluation of a novel liquid nitrogen cryoprobe

A novel liquid nitrogen cryoprobe is developed in the present study. The inlet, handle, the vapor-liquid separator and the heat transfer segment of the cryoprobe are designed to be detachable. This flexible construction provides many distinct features, such as good maneuverability, high safety and low cost. A new vapor-liquid separator is made to ensure the free flow of the liquid nitrogen and increase the probe freezing capacity. The wall temperatures at the different locations along the cryoprobe are measured in the air, gel and brine, with the various driven pressure ranging from 0.3 to 0.6 MPa. The results are compared to the other probe. It is found that the precooling time of the probe is shortened significantly. The present cryoprobe offers better cooling performance to the existing cryoprobe. The heat flux transferred from the surrounding air or brine to the cryoprobe is estimated, and it is concluded that the boiling pattern in the probe is the film boiling and suggestions for further improvement of the cryoprobe's performance is made based on the analysis.

Shape recovering of live endothelial cell under atomic force microscopy imaging

When live endothelial cells imaged using atomic force microscopy (AFM), distortion of the cell shape could be caused by the interaction between the probe and cell membrane, which depends on the force and the scanning speed used. In this study, a shape recovering method was developed. Two forces were considered in the method: the vertical and the lateral force of the tip exerted on the cell membrane during the scanning. The cell membrane was modeled as an elastic material. Results show that the recovering is necessary to reveal the original cell shape. The AFM tip effect should be taken into consideration in the live cell morphological study using AFM.

Morphological study of endothelial cells during freezing

Microvascular injury is recognized as a major tissue damage mechanism of ablative cryosurgery. Endothelial cells lining the vessel wall are thought to be the initial target of freezing. However, details of this injury mechanism are not yet completely understood. In this study, ECMatrix 625 was used to mimic the tumour environment and to allow the endothelial cells cultured in vitro to form the tube-like structure of the vasculature. The influence of water dehydration on the integrity of this structure was investigated. It was found that the initial cell shape change was mainly controlled by water dehydration, dependent on the cooling rate, resulting in the shrinkage of cells in the direction normal to the free surface. As the cooling was prolonged and temperature was lowered, further cell shape change could be induced by the chilling effects on intracellular proteins, and focal adhesions to the basement membrane. Quantitative analysis showed that the freezing induced dehydration greatly enhanced the cell surface stresses, especially in the axial direction. This could be one of the major causes of the final breaking of the cell junction and cell detachment.

Quantification of quantum dots in HUVECs by confocal laser scanning microscopy

Quantum dots (QDs) are emerged as a new class of fluorescent probes for many biological and biomedical applications. Comparing with conventional fluorescent probes, they have substantial advantages such as bright fluorescence, narrow emission, broad excitation band and high photostability. However, little is known about the toxicity of nanoscale particles to biological systems. In this study, the interaction between 3-Mercaptopropionic acid capped CdTe QDs and HUVECs was studied quantitatively in vitro. Fluorescent intensity of QDs in cells was measured by confocal fluorescence laser scanning microscopy. The results showed that the amount of QDs absorbed by cells is dependent on concentration and incubation time. Further, the viability of cells incubated with QDs was investigated using MTT assay. Dramatic dose-dependent decrease in cellular viability was observed.

Study of non-uniform nanoparticle liposome extravasation in tumour

The effect of hyperthermia on the nanoparticle extravasation in different tumour regions was investigated in real time using confocal laser scanning microscopy. Murine mammary carcinoma 4T1 was implanted in the nude mice dorsal skin-fold window chamber. Tumour angiogenesis was observed through the window chamber on days 4, 7, 8 and 10 after the implantation. In 10 days, the tumour became 1-2 mm in diameter and 150 microm thick. Most vessels were found to be <15 microm in diameter. Histological examination showed that there were fewer vessels in a more ordered branching pattern inside the tumour than in the tumour periphery. After hyperthermia at 42 degrees C for 1 h, numerous erythrocytes were found in the peripheral region. Extravasation of rhodamine-labelled 100 nm nanoparticles in different tumour regions under both normal and hyperthermic conditions (34 and 42 degrees C) was quantified using confocal fluorescence microscopy. The relative fluorescence intensity hardly changed in tissue at 34 degrees C, but increased by the local hyperthermia at 42 degrees C. In particular, the relative intensity in the tumour periphery was more than 120 as compared to 40 in the tumour centre, after 1 h hyperthermia. Results showed that the thermally induced liposome nanoparticle extravasation was heterogeneous in tumour, owing to the non-uniform distribution of tumour vasculature. Further, the degree of vascular damage was found to be more severe in the tumour periphery, which is likely due to the high thermal sensitivity of newly formed tumour vessels in this region.

Study of SARS transmission via liquid droplets in air

Microscale liquid droplets could act as the SARS carriers in air when released from an infected person through breathing, coughing, or sneezing. In this study, a dynamic model has been built to quantitatively investigate the effect of the relative humidity on the transport of liquid-droplets in air using coupled mass transfer and momentum equations. Under higher relative humidity, the exhaled liquid droplets evaporate slowly. Larger droplets fall faster, which could reduce the probability of the droplets inhalation. This may be one of the most important factors that influence the SARS transmission in air.

[Isolation and elucidation of chemical constituents of shandanshaoyao decoction (II)]

OBJECTIVE

To study the chemical constituents of Shandanshaoyao Decoction.

METHOD

The sample was prepared by boiling water, then precipitated by 75% of ethanol. The ethanol soluble fraction was extracted by chloroform, ethyl acetate and n-butanol, respectively. The extracts were isolated using macroreticular resin, silica gel and polyamide column chromatography, and then the chemical constituents were identified by chemical and spectroscopic methods.

RESULT

Nine compounds were isolated from the n-butanol extract and water soluble fraction, and elucidated as vitexin, quercetin, hyperoside, rutin, paeoniflorin, protocatechaldehyde, (+)-catechin, danshensu and citric acid respectively.

CONCLUSION

The chemical constituents of traditional Chinese medicinal preparations Shandanshaoyao Decoction were reported for the first time.

[Isolation and elucidation of chemical constituents of Shandanshaoyao Decoction(I)]

OBJECTIVE

To study the chemical constituents of Shandanshaoyao Decoction.

METHOD

The sample was prepared using boiling water, then precipitated by 75% ethanol. The ethanol soluble fraction was extracted by chloroform, ethyl acetate and n-butanol respectively. The extracts were isolated using silica gel and polyamide column chromatography, and the chemical constituents were identified by chemical and spectroscopic methods.

RESULT

Six compounds were isolated from the chloroform and ethyl acetate extracts, and elucidated as tanshinone IIA, benzoic acid, ferulic acid, cryptotanshinone, beta-stitosterol and ursolic acid respectively.

CONCLUSION

A preliminary study on the chemical constituents in traditional Chinese compound recipe Shandanshaoyao Decoction is reported.

Neurotoxic effect of high dose of L-(+)-2-amino-3-phosphonopropionic acid in rats after intracaudatal injection

AIM

To investigate neurotoxic effect of L-(+)-2-amino-3-phosphonopropionic acid (L-AP3), a partial agonist/antagonist of metabotropic glutamate receptors (mGluRs), and explore the underlying mechanisms.

METHODS

Consciousness and behavior of rats were evaluated after injection of L-AP3, D-(+)-2-amino-3-phosphonopropionic acid (D-AP3, an isomer of L-AP3) or L-(+)-2-amino-4-phosphonobutyric acid (L-AP4, an agonist of mGluRs) into right caudatum. Brain water, Na+, K+, and Ca2+ contents as well as the permeability of blood brain barrier (BBB) were determined 6 h after treatment of these chemicals. Histological changes at the same time point were also observed.

RESULTS

Rats treated with L-AP3 600 nmol but not 60 nmol became somnolentia. Inject ion of L-AP3 600 nmol induced a great increase of brain water, Na+, and Ca2+ contents, and a decrease of brain K+ content (P < 0.01). Meanwhile, the permeability of BBB was also increased (P < 0.01). Electron microscopic study revealed remarkable swelling of astrocytes and degenerative changes of neurons in chemical-treated caudatum. The neurotoxic effect of L-AP3 was not mimicked by D-AP3 or L-AP4 (P < 0.05). DL-2-Amino-5-phosphonovaleric acid, an antagonist of N-methyl-D-aspartate (NMDA) receptors, attenuated the changes induced by L-AP3 (P < 0.05), whereas (+/-)-alpha-methyl-(4-carboxyphenyl)glycine, a non-subtype specific antagonist of mGluRs, failed to block the effect of L-AP3.

CONCLUSION

Intracaudatal injection of L-AP3 induced neurotoxic effect characterized by vasogenic brain edema, neuronal degeneration, and high brain Ca2+ content. Neurotoxic effect of L-AP3 was stereoselective and might be mediated by phospholipase C activation and partially involvement of NMDA receptors.

[Separation and determination of flavonols in the flowers of Carthamus tinctorius by RP-HPLC]

Carthamus tinctorius L. is a kind of traditional Chinese medicine used in the treatment of uterine congestion, cardio-vascular disease, thrombosis and so on. Eight flavonoids have been isolated from its flowers. A reversed phase HPLC method for the separation and determination of the three flavonols: rutin (I), quercetin(II) and kaempferol(III) in the flowers of Carthamus tinctorius L. is described. The column was 25 cm x 4.6 mm ID, packed with YWG-C18(10 microns). The mobile phase was a mixture of MeOH-H2O-H3PO4(48.5:51.5:0.25, pH 3.5). The flow rate was 1.0 ml.min-1. Daidzein was used as an internal standard. UV detection was performed at 360 nm. The relative standard deviation of the method was 1.1-2.6%. The calibration curves showed good linearity over the range of 0.11-0.80 microgram, gamma = 0.9995-0.9998 and detection limits were 2.0-20.0 ng. The recoveries were 97.8%-98.9% for the three flavonols. The method is simple, fast, sensitive and accurate and has been applied to the analysis of Carthamus tinctorius L. of different sources. It can also be used for the quality control of safflower preparations for clinical uses.

[The protective effect of puerarin on cultured rat cerebral cortical astrocytes]

AIM

To study the effects of puerarin (Pue) on impairment of rat astrocytes in primary cell culture induced by oxygen-glucose deprivation (OGD) or sodium glutamate (Glu).

METHODS

Astrocyte damage induced by (OGD), Glu or (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD), as well as the action of Pue was measured by determining the intracellular water space (as measured by 3-O-methyl-[1- 3H]D-glucose uptake) of astrocytes and the leakage of lactate dehydrogenase (LDH) from astrocytes.

RESULTS

Following the exposure to OGD for 5 h, 0.5 mmol/L Glu or 1 mmol/L trans-ACPD for 1 h, the astrocyte volume and LDH leakage from astrocytes were increased. 0.1 mmol/L Pue, when co-incubated with OGD, Glu or trans-ACPD, reduced astrocytic swelling and the LDH leakage.

CONCLUSION

Pue had protective effects on astrocytes damaged by OGD, Glu or trans-ACPD.

Studies on the three-dimensional temperature transients in the canine prostate during transurethral microwave thermal therapy

Thermal therapy of benign prostatic hyperplasia requires accurate prediction of the temperature distribution induced by the heating within the prostatic tissue. In this study, the Pennes bioheat transfer equation was used to model the transient heat transfer inside the canine prostate during transurethral microwave thermal therapy. Incorporating the specific absorption rate of microwave energy in tissue, a closed-form analytical solution was obtained. Good agreement was found between the theoretical predictions and in-vivo experimental results. Effects of blood perfusion and the cooling at the urethral wall on the temperature rise were investigated within the prostate during heating. The peak intraprostatic temperatures attained by application of 5, 10, or 15 W microwave power were predicted to be 38 degrees C, 41 degrees C, and 44 degrees C. Results from this study will help optimize the thermal dose that can be applied to target tissue during the therapy.

Evaluation of the effectiveness of transurethral radio frequency hyperthermia in the canine prostate: temperature distribution analysis

The heating pattern of a transurethral radio frequency (RF) applicator and its induced steady-state temperature field in the prostate during transurethral hyperthermia treatment were investigated in this study. The specific absorption rate (SAR) of the electromagnetic energy was first quantified in a tissue-equivalent gel phantom. It was used in conjunction with the Pennes bioheat transfer equation to model the steady-state temperature field in prostate during the treatment. Theoretical predictions were compared to in vivo temperature measurements in the canine prostate and good agreement was found to validate the model. The prostatic tissue temperature rise and its relation to the effect of blood perfusion were analyzed. Blood perfusion is found to be an important factor for removal of heat especially at the higher RF heating level. To achieve a temperature above 44 degrees C within 10 percent of the prostatic tissue volume, the minimum RF power required ranges from 5.5 W to 36.4 W depending on the local blood perfusion rate (omega = 0.2-1.5 ml/gm/min). The corresponding histological results from the treatment suggest that to obtain better treatment results, either higher RF power level or longer treatment time (> 180 minutes) is necessary. This is consistent with the predictions from the theoretical model developed in this study.

Estimation of blood perfusion using phase shift in temperature response to sinusoidal heating at the skin surface

A closed form analytical solution of the Pennes' bio-heat equation was obtained for temperature distributions in the skin tissue subject to the sinusoidal heat flux. Phase shifts in the surface temperature response were revealed to be related to local blood perfusion rate and heating frequency. The influence of the thermal contact resistance on the perfusion estimation was investigated. It has been proved that this influence is relatively small because of the phase shift based estimation and can be effectively eliminated by application of highly conductive grease. This analysis provides the theoretical foundation for a new noninvasive modality of blood perfusion estimation based on the surface temperature measurement which can have significant applications in future clinical practices.