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Biomedical subjects

H Cai

Publications and source records attributed to H Cai.

At least 91 records · Page 5Linked to original sources
PubMed1999

[Changes of serum cardiac troponin T in patients undergoing cardiac surgery].

We detected the changes of serum cardiac troponin T(cTn T) content and serum cardiac enzyme activities in 15 patients with cardiopulmonary bypass during cardiac operation. The central venous blood samples were collected to measure the serum concentration of cTn T by enzyme immunoassay methods and activities of lactate dehydrogenase(LDH), creatine kinase(CK), and creatine kinase isoenzyme(CK-MB) by biochemical methods. The content of cTn T and activities of LDH, CK, and CK-MB increased significantly after cardiac surgery. There was positive correlation between cTn T and aortic cross clamping time (r = 0.6014, P < 0.05), but there was no correlation between CK-MB and aortic cross clamping time (r = 0.4712, P > 0.05). We conclude that serum cTn T and CK-MB can monitor cardiac ischemic reperfusion injury and can evaluate myocardial protection methods during cardiac operation, but cTn T is better than CK-MB.

Adolescent↗
PubMed1999

[Use of transcranial Doppler in monitoring cerebral blood flow velocity during peri-operation].

Transcranial Doppler was used to monitor 45 patients' middle cerebral artery blood flow velocity during anesthesia and cardiopulmonary bypass. The result was that the change in middle cerebral artery blood flow velocity was in correspondence with cerebral blood flow. This paper suggests that transcranial Doppler is a simple and practical instrument for monitoring cerebral blood flow.

Adolescent↗
PubMed1999

[Effect of glycyrrhizin on plasma endothelin and serum nitric oxide in myocardial ischemia reperfusion rabbits].

Effects of glycyrrhizin on plasma endothelin(ET), serum nitric oxide(NO) and creatine phosphokinase(CPK) activity of myocardial tissues were observed in myocardial ischemia/reperfusion rabbits. The results indicated that the CPK activity and plasma ET level increased and serum NO level decreased significantly after myocardial ischemia/reperfusion. In comparing with control, glycyrrhizin not only reduced significantly the increased plasma ET level and CPK activity of myocardial tissues, but also increased markedly the producing and releasing of NO(P < 0.01). All these facts suggest that glycyrrhizin exerts obviously protective effects on myocardial injury induced by ischemia/reperfusion.

Animals↗
PubMed1999

[Changes in lipoprotein (a) and the relation between lipoprotein (a) and endothelin in patients during upper abdominal surgery].

OBJECTIVE: We observed the changes in both serum lipoprotein(a) [Lp(a)] and plasma endothelin (ET) during upper abdominal surgery under intravenous combined with inhalation anesthesia and we also analyzed their correlativity. METHODS: Fifteen patients, scheduled for upper abdominal surgery, were anesthetized with total does of fentanal 8-12 micrograms.kg-1 and inhalation of 1-2 MAC enflurane. Serum Lp(a) and plasma ET at pre-anesthesia, pre-operation, 1 h from the start of operation and 30 min after operation were determined. RESULTS: The average concentrations of Lp(a) and ET were increased at 1 h from the start of operation compared with pre-anesthesia, but had no statistical significance. Lp(a) and ET were significantly higher at 30 min after operation than pre-anesthesia(P < 0.05). CONCLUSION: Lp(a) and ET have a close relation in advancing cardio-cerebral blood vessel diseases.

Abdomen↗
PubMed1999

[A model of closed epidural balloon inflation brain injury in rats].

OBJECTIVES: To establish an animal model of closed brain epidural occupancy trauma in rats. METHODS: Sixty-eight Wistar rats were randomly divided into 7 groups: normal control group(Group A), sham-operated group(Group B), and 5 experimental groups. The last ones included: Group C in which water was injected 0.05 ml into balloon and kept for 1 hour; Group D injected 0.05 ml and kept for 3 hours; Group E injected 0.1 ml and kept for 1 hour; Group F injected 0.1 ml and kept for 2 hours. Group B, C, D were kept maintaining and observing for two days after operation, respectively. Group E was divided into EI (maintaining for two days) and EII (for three days). RESULTS: Of all the experimental groups, the mortality rate during acute phase was 100% in Group F, 28% in Group E, 50% in Group D, and 0% in Group C. Four rats died during the raising-up period in Group E. Both ICP and cerebral water content were increased in 46 survived rats, and nerve functions were damaged in all the experimental groups. Pathologic changes read as follows: Hemorrhage was found in damage-area; injury and dead cells were seen in compressed region. These changes became worse with time prolonged and injury degree developed. CONCLUSIONS: The method is simple, reproducible and economical, well showing the pathological classification of epidural occupancy trauma.

Animals↗
PubMed1999

[Determination of AR parameters for multi-channel upper limb EMG].

In this study, a segment LS method was used to determine the AR parameters for multi-channel upper limb EMG. Different sampling frequencies, time-windows and attenuation factors were tested and an optimum selection was obtained. According to the experiment result, the segment LS algorithm should be the best method compared with others.

Algorithms↗
PubMed1999

[Species identification of Mycobacterium tuberculosis with insertion elements].

The Insertion Sequence(IS) element IS6110 and IS1081 of M. tuberculosis complex were used as template to prepare probes for typing strains by means of restriction fragment length polymorphisms (RFLP). Chromosomal DNA of M. tuberculosis H37Ra, H37Rv, M. bovis digested with EcoR I, Pst I, Sal I, BamH I, Pvu II was subjected to Southern Blot analysis With labeled 317bp from IS6110 and 248 bp from IS1081. The results indicated that for M. tuberculosis complex, IS1081 cannot be used to type strains, IS6110 can be used to distinguish strains into broad groups and is an excellent epidemiological tool for studying outbreaks. An investigation of forty-six M. tuberculosis isolates by IS6110 RFLP revealed that M. tuberculosis strains not only are of highly polymorphic, but also are presentin multiple copies ranging from 7 to 18 copies.

DNA Probes↗
PubMed1998

Neural crest-specific and general expression of distinct metalloprotease-disintegrins in early Xenopus laevis development.

Metalloprotease-disintegrins are a family of membrane-anchored glycoproteins that have been implicated in diverse cellular processes, including fertilization and myoblast fusion, release of TNFalpha from the plasma membrane, and neurogenesis. Here we report the cloning of cDNAs encoding three full-length (xMDC9, xMDC11b, and xMDC13), and one partial (xMDC11a) metalloprotease-disintegrin from the amphibian Xenopus laevis, and the analysis of their expression during early X. laevis development and in adult tissues. The most notable finding was the highly localized and specific expression pattern of xmdc11a at the tailbud stage in the cranial neural crest and in a subset of neural tube cells in the trunk region. In contrast, expression of the closely related xmdc11b was not detectable during the early stages of X. laevis development, and remained low in the adult tissues examined here. Distinct expression patterns were also observed for two other highly related X. laevis genes, xmdc13 and adam13 (Alfandari et al., 1997). While adam13 is expressed in the somitic mesoderm and in neural crest cells, but not in adult testis, xmdc13 expression is low and ubiquitous in the developing embryo, but is clearly present in adult testis. Finally, xmdc9, the putative orthologue of human and mouse mdc9, was found at all stages of development, and in all tissues examined, suggesting a function that may be utilized by most or all cells. The noteworthy features of these four xmdc genes and the implications of their distinct spatial and temporal expression patterns are discussed.

Amino Acid Sequence↗
PubMed1998

Binding of a burst-phase intermediate formed in the folding of denatured D-glyceraldehyde-3-phosphate dehydrogenase by chaperonin 60 and 8-anilino-1-naphthalenesulphonic acid.

Upon dilution, D-glyceraldehyde-3-phosphate dehydrogenase (GADPH) that has been fully inactivated, but only partially unfolded, in dilute guanidine hydrochloride (GuHCl) recovers activity completely. The fully unfolded enzyme, however, is re-activated only to a limited extent after dilution, and refolds rapidly in a burst phase to a partially folded intermediate characterized by increases in both the emission intensity of intrinsic fluorescence and binding to 8-anilino-1-naphthalenesulphonic acid (ANS). This intermediate aggregates with a time lag of a few minutes, and the aggregation can be suppressed completely by chaperonin 60 (GroEL). Stoichiometric analysis of the suppression of GAPDH re-activation by GroEL suggests that the tetradecameric GroEL binds to a dimeric GAPDH folding intermediate. This intermediate can be re-activated by ATP or ATP/chaperonin 10 (GroES) to an extent considerably greater than that obtained on spontaneous re-activation of the fully denatured enzyme upon dilution. Probing with a fluorescent derivative of NAD+ shows that this folding intermediate does not have a native conformation at the active site. The similar profiles of the effects of GroEL and ANS on the re-activation of GAPDH denatured by different concentrations of GuHCl suggest that GroEL and ANS recognize and bind to the same folding intermediate, which is similar to the relatively stable, partially unfolded, state of the enzyme denatured in 0.5-1.0 MGuHCl. However, the complexes of the intermediate with GroEL or ANS appear to be different, in that GroEL, but not ANS, suppresses aggregation and assists folding in the presence of ATP.

Adenosine Triphosphate↗
PubMed1998

Effects of long-acting angiotensin-converting enzyme inhibitor, imidapril, on the lower limit of cerebral blood flow autoregulation in hypertensive rats.

The objective of the present study was to examine the effects of a long-acting angiotensin converting enzyme inhibitor, imidapril ((4S)-1-methyl-3-¿(2S)-2-[N-(1S)-1-ethoxycarbonyl-3-phenylpropyl) amino] propionyl¿-2-oxoimidazolidine-4-carboxylic acid hydrochloride), for 7 days on the cerebral blood flow autoregulatory response to hypotension in hypertensive rats. We measured the cerebral blood flow at rest and during hemorrhagic hypotension, using laser-Doppler flowmetry. At the same time, the absolute baseline cerebral blood flow values in the parietal cortex were quantified with the hydrogen clearance method. After administration of imidapril at a dose of 5 mg/kg/day for 7 days, the resting value of mean arterial blood pressure was significantly decreased by 25 mm Hg (P < 0.001), cerebral vascular resistance was lowered by 14.4% (P < 0.05) and the lower limit of cerebral blood flow autoregulation was shifted to a lower level, 106+/-11 mm Hg (mean +/- S.D.), from 137+/-8 mm Hg in the control group (P < 0.001), while resting cerebral blood flow remained unchanged. The present results demonstrated that imidapril preserves cerebral blood flow and significantly shifts the lower limit of cerebral autoregulation towards lower blood pressure levels.

Adenosine Triphosphate↗
PubMed1998

Gene expression of the proteasome in rat lens development.

To study the involvement of the proteasome in ocular lens cell proliferation and differentiation, a partial cDNA encoding rat S7, a subunit of the ATPase complex that regulates the 20S proteasome (multicatalytic proteinase complex), and RC3, a subunit of the 20S proteasome moiety, were cloned and used to compare relative levels of S7 and RC3 mRNAs. mRNA was measured, using a competitive RT-PCR assay, in isolated lens cells or explant cultures induced to differentiate or proliferate. During differentiation, S7 mRNA levels increased (1.7 fold) and RC3 mRNA levels remained the same compared to mRNA in quiescent cells. During proliferation, RC3 mRNA levels were elevated (2 fold) and S7 mRNA levels remained the same. This demonstrated that representative proteasome and ATPase complex mRNA levels are regulated differentially during differentiation and proliferation. The maintenance of proteasome subunit mRNA and increase in ATPase complex subunit mRNA observed in differentiating lens cells is in contrast to the patterns of expression that have been reported for other differentiating cells, which down-regulate the 20S and/or 26S proteasome. This suggests that the role of the proteasome in cell development is cell specific.

Acetylcysteine↗
PubMed1998

Triterpenoid saponins from Berneuxia thebetica.

Four triterpenoid saponins were isolated from Berneuxia thibetica. On the basis of chemical and spectroscopic evidence, three new saponins, berneuxia saponins A, B and C, were elucidated as 21-tigloylbarringtogenol C-3 beta-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->3)[bet a- D-glucopyranosyl(1-->2)-beta-D-glucuronopyranoside], 28-tigloylbarringtogenol C-3 beta-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->3)[bet a- D-glucopyranosyl(1-->2)-beta-D-glucuronopyranoside] and 16 alpha-28-dihydroxyolean-12-en-21-one-3-O-alpha-L-rhamnopyranosyl(1 -->2) -beta-D-galactopyranosyl(1-->3)[beta-D-glucopyranosyl(1-->2)-beta-D- glucuronopyranoside]. The known saponin was desacyl jegosaponin.

Carbohydrate Conformation↗
PubMed1998

Capillary electrophoretic separation of weak base enantiomers using the single-isomer heptakis-(2,3-dimethyl-6-sulfato)-beta-cyclodextrin as resolving agent and methanol as background electrolyte solvent.

The sodium salt of the single-isomer, heptakis-(2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-betaCD) was used as resolving agent in the capillary electrophoretic (CE) separation of weak base enantiomers in pure methanol background electrolytes (BEs). According to the requirements of the charged resolving agent migration model of CE enantiomer separations (CHARM model), a high buffer-capacity, low pH methanolic BE was created from 25 mM phosphoric acid and 12.5 mM NaOH. In this BE, the solubility of HDMS-betaCD was as high as 50 mM, permitting the realization of very high separation selectivities and short separation times for the fully protonated weak base enantiomers.

Cyclodextrins↗
PubMed1998

Comparison of HPLC, capillary electrophoretic and direct spectrofluorimetric methods for the determination of temoporfin-poly(ethylene glycol) conjugates in plasma.

High-performance liquid chromatographic (HPLC), capillary electrophoretic (CE) and direct spectrofluorimetric methods for the determination of temoporfin-poly(ethylene glycol) 2000 conjugate (m-THPC-PEG 2000) in plasma are described and compared. m-THPC-PEG 2000 in plasma was quantitatively extracted (recovery 101-107%) with CH3OH-DMSO (4 + 1 v/v). The supernatant after centrifugation was used for HPLC, CE or direct spectrofluorimetric determination. The major drawback of the HPLC method was that it gave a broad and split peak even under gradient elution conditions, resulting in difficulty in detection and quantification. This is because m-THPC-PEG 2000 consists of a group of compounds with an average molecular mass of approximately 8680 Da owing to the wide molecular mass distribution of PEG 2000 used in the synthesis of the drug. m-THPC-PEG 2000 gave a single and relatively sharp peak when separated by CE with sodium tetraborate buffer (pH 9.45) in the presence of sodium dodecyl sulfate as the running buffer. However, this method lacks the necessary sensitivity for detecting the drug in plasma extract because of the limited sample volume that can be injected. Direct spectrofluorimetry is the method of choice because of its simplicity, specificity and sensitivity. Using an excitation wavelength of 423 nm and the specific emission maximum of 657 nm, the fluorescence intensity could be sensitively measured. The calibration curve constructed by plotting fluorescence intensity against concentration was linear within the range 1.32-1056 ng ml-1. The detection limit (S/N = 3) was 1.32 ng ml-1 and the limit of quantification (S/N = 10) was 2.24 ng ml-1. The precision and reproducibility were assessed by repeated analysis (n = 24) of spiked plasma samples at 350.8 and 699.3 ng ml-1. The RSD was 4.5% and 1.6%, respectively.

Adjuvants, Pharmaceutic↗
PubMed1998

Visualization of chronic neck-shoulder pain: impaired microcirculation in the upper trapezius muscle in chronic cervico-brachial pain.

This study pertains to the 71 patients who had received a diagnosis of cervico-brachial pain syndrome after thorough clinical examination of a total series of 300 patients, who had been referred to the National Insurance Hospital in Tranås because of chronic neck pain that interfered with their ability to work. Changes in trapezius muscle blood flow and EMG were examined and related to the anamnesis and physical findings. The microcirculation in the upper part of the right and left trapezius muscles was examined simultaneously by using optical laser-Doppler single-fibres after insertion into the muscle directly via the skin. Continuous recordings were made during stepwise increased static contraction determined electro-myographically. Signal processing was performed on-line by computer. MRT of the cervical spine was performed in 12 patients. None showed nerve root affliction. Ten showed a bulging intervertebral disc and two, a narrowed nerve hole (lateral stenosis). The muscle blood flow (LDF) was significantly lower in the most painful side compared with the opposite side in the group of 41 patients with predominantly unilateral pain (21 women and 20 men). A lowered blood flow was also found when the 21 females in this group was compared with a normal control group of 20 healthy women. The patients had lower rms-EMG and EMG mean power frequency (MPF) in the painful side compared with the opposite side. A further lowering of the MPF was observed with induced fatigue. It was concluded that the chronic neck pain in cervico-brachial syndrome can become visualized by the finding of lowered blood flow of the trapezius muscle which seems to be an expression of the chronic neck pain.

Adult↗
PubMed1998

A model for binaural response properties of inferior colliculus neurons. I. A model with interaural time difference-sensitive excitatory and inhibitory inputs.

A model was developed that simulates the binaural response properties of low-frequency inferior colliculus (IC) neurons in response to several types of stimuli. The model incorporates existing models for auditory-nerve fibers, bushy cells in the cochlear nucleus, and cells in medial superior olive (MSO). The IC model neuron receives two inputs, one excitatory from an ipsilateral MSO model cell and one inhibitory from a contralateral MSO model cell. The membrane potential of the IC model neuron (and the other model neurons) is described by Hodgkin-Huxley type equations. Responses of IC neurons are simulated for pure-tone stimuli, binaural beat stimuli, interaural phase-modulated tones, single binaural clicks, and pairs of binaural clicks. The simulation results show most of the observed properties of IC discharge patterns, including the bimodal and unimodal interaural time difference (ITD) functions, sensitivities to direction and rate of change of ITD, ITD-dependent echo suppression, and early and late inhibitions in response to clicks. This study demonstrates that these response properties can be generated by a simple model incorporating ITD-dependent excitation and inhibition from binaural neurons.

Acoustic Stimulation↗