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Biomedical subjects

H S Zhu

Publications and source records attributed to H S Zhu.

14 recordsLinked to original sources
PubMed2006

Preparation of bioelectret collagen and its influence on cell culture in vitro.

Collagen extracted from pigskin was corona-charged negatively by a specifically designed device. Different charging voltages, temperatures and times were applied to prepare collagen bioelectret. The decline of the surface potential of the bioelectret under different treatment was then determined. The data showed that the surface potential was markedly varied with the charging conditions. The optimal values of three parameters for charging collagen coatings were defined as follows: voltage, 8 KV; temperature, 40 degrees Celsius; time, 25 min. Treatment of the bioelectret with distillated water, or saline solution (0.9%) or culture medium induced a sharp decrease of the surface potential. In addition, we investigated the effects of the charged collagen on cell growth and intracellular calcium level of three types of cultured mammalian cell lines, including Chinese hamster ovary CHO cells, human cervix uteri tumor HeLa cells and human promyelocytic HL-60 cells. Cell growth and the intracellular calcium level were determined by MTT reagent-based assay and a fluorescent probe Fura-2, respectively. The results showed that negatively charged collagen stimulated the growth of CHO or HL-60 cell line but inhibited the growth of HeLa cell line. Furthermore, after attaching to the charged collagen, the intracellular calcium level of CHO cells increased, while that of HeLa cells decreased. Thus we proposed for the first time that collagen bioelectret could differentially modulate the growth of different cells, by an unknown mechanism that probably involves a role of intracellular calcium.

Animals↗
PubMed2002

N-desulfated non-anticoagulant heparin inhibits leukocyte adhesion and transmigration in vitro and attenuates acute peritonitis and ischemia and reperfusion injury in vivo.

OBJECTIVE: Heparin, a highly sulfated proteoglycan, is known to have strong anticoagulant and anti-inflammatory activities. Here we sought to generate a heparin derivative, which had a significantly lower anticoagulant activity while retaining its strong anti-inflammatory activity. MATERIALS AND METHODS: Heparin was chemically modified and this discrete set of the heparin derivatives was tested for their anticoagulant activities, such as activated partial thromboplastin time (APTT), and anti-inflammatory activities, such as leukocyte adhesion and transmigration in vitro and acute peritonitis and ischemia and reperfusion injury in vivo. RESULTS: We found that an N-desulfated heparin had 188-fold (compared to heparin) and 32-fold (compared to low molecular weight heparin; LMWH) reductions of APTT. The N-desulfated heparin inhibited adhesion of human promyeloid HL-60 cells to the stimulated human umbilical vein endothelial cells (HUVECs) under a physiological shear stress. It also prevented the transmigration of human neutrophils through the monolayers of the stimulated HUVECs. Further, intravenous administration of this compound attenuated the peritoneal infiltration of neutrophils in a mouse model of acute peritonitis, and reduced tissue edema and leukocyte deposition in a rabbit ear model of ischemia and reperfusion injury. CONCLUSION: It is to our best knowledge that the N-desulfated heparin has the lowest anticoagulant activity among LMWH and chemically modified heparin derivatives, while preserving a potent anti-inflammatory activity. These combined properties appear to suggest it as a safer medicine for treatment of inflammation.

Acute Disease↗
PubMed2002

Photo-induced cytotoxicity of malonic acid [C(60)]fullerene derivatives and its mechanism.

The biological activities of fullerenes have attracted extensive attention in recent years. The aim of this paper is to study the relation of the photo-induced cytotoxicity of fullerene derivatives to their chemical structures as well as the possible cellular mechanism involved in the photocytotoxicity. Three C(60) derivatives with two to four malonic acid groups (DMA C(60), TMA C(60) and QMA C(60)) were prepared and the cytotoxicity of these compounds against HeLa cells was determined by MTT. Cell cycle was measured by flow cytometry. The results showed that the cytotoxicity of the malonic acid C(60) derivatives was irradiation- and dose-dependent. The sequence of their photo-induced growth inhibition was DMA C(60)>TMA C(60)>QMA C(60). Hydroxyl radical quencher mannitol (10mM) was not able to prevent cells from the damage induced by irradiated DMA C(60). DMA C(60), together with irradiation, was found to have an ability of inducing a decrease in the number of G(1) cells from 63 to 42% and a rise in that of G(2)+M cells from 6 to 26%. These data indicated that the number of malonic acid molecules added to C(60) played an important role in the phototoxicity, and the blockage of cell cycle might be a mechanism of this activity.

Carbon↗
PubMed2000

Effects of extracts from sporoderm-broken spores of Ganoderma lucidum on HeLa cells.

The effects of extracts from Ganoderma lucidum spores on the growth of human cervix uteri tumor HeLa cells as well as on the cell cycle and intracellular calcium level were investigated. Alcohol extracts were prepared from sporoderm-broken and sporoderm-nonbroken spores (termed extract I and extract II) of G. lucidum. Extract I was then subjected to silica gel chromatography to obtain extract III. Cytotoxicity was examined by means of trypan blue exclusion and MTT tests. It was found that extract I and extract III, but not extract II strongly inhibited the growth of HeLa cells, and that extract III was more effective than extract I. Moreover, extract III was shown to be capable of blocking the cell cycle at the transition from G1 to S phase and inducing a marked decrease of intracellular calcium level, determined by flow cytometry and the specific fluorescent calcium probe Fura-2, respectively. These results imply that (1) the breaking of G. lucidum spores improves the release of cytotoxic activity and (2) the effective extract might influence the cell cycle and cellular signal transduction by altering the calcium transport system.

Calcium↗
PubMed2000

[Extraction and separation of antitumor components from Ganoderma lucidum (Leyss. ex Fr.) Karst].

OBJECTIVE: To examine the variation of alcohol extraction rates of Ganoderma lucidum spores with different rates of wall-wrack, and analyze the antitumor components of alcohol extract by chromatography. METHOD: The G. lucidum spores were soaked and extracted with absolute alcohol. The alcohol extract was chromatographed on a silica gel column and HPLC in proper order, and the antitumor activity of every eluted fraction was represented by its cytotoxicity towards Hela cells. RESULT: Extraction rates 5%, 25% and 33% corresponded to wall-wrack rates 0%, 60%-80% and 99% respectively. The alcohol extract from spores with the highest wall-wrack rate was chromatographed on a silica gel column, eluting successfully with CHCl3, EtOAc and CH3OH in order. The CHCl3 fraction had not any antitumor activity, while this activity of CH3OH fraction was 34 times greater than that of EtOAc fraction. HPLC analysis found out that two mixtures(II1 and II3) possess significant antitumor activity in vitro. CONCLUSION: The weight of alcohol extract from spores with wall-wrack was far greater than that of spores without. The antitumor components of G. lucidum spores could be analyzed with methanol-water on a reverse HPLC.

Antineoplastic Agents, Phytogenic↗
PubMed1991

A microprocessor-based data-acquisition system for measuring plantar pressures from ambulatory subjects.

We have developed a portable microprocessor-based data-acquisition system to measure discrete plantar pressures within the shoe from ambulatory subjects. The system offers improved accuracy, repeatability, portability, and flexibility not available in current commercial systems. It consists of 14 conductive polymer pressure sensors, 14 analog amplifiers, an 8-bit analog-to-digital converter, a microprocessor, 120 kbytes of memory space, and a parallel I/O interface. Seven pressure sensors are embedded within each insole and located at the posterior heel, anterior heel, the four metatarsal heads, and hallux of each foot. The system is capable of continuously sampling 14 channels of pressure data for 7 min at a 20-Hz sample rate. The recorded data are downloaded into a microcomputer for further processing, analysis, and display. Foot pressures have been acquired from a sensate subject during multiple walking trials.

Diagnosis, Computer-Assisted↗
PubMed1991

[Surgical treatment of infective endocarditis].

Nineteen patients with infective endocarditis underwent surgery. Congenital heart disease was found in 6 patients, valve disease in 13. Seven patients had history of rheumatism. Congestive heart failure was noted in 17 patients, arterial embolism in 3, and pulmonary infarction in 1. Blood culture was positive in 36.8%, while vegetations were detected echocardiographically in 58.8% of the patients. Selective surgery was performed in 17 patients and emergency operation in the rest two. There was no operative death. Follow-up for 3-109 months after operation showed no evidence of recurrent endocarditis. We suggest that early surgical treatment is mandatory for intractable infective endocarditis if excellent result is expected.

Adolescent↗
PubMed1991

Modified Wicomb's apparatus for preservation of heart for 24 hours.

To prolong the time of heart preservation, we modified the Wicomb's perfusion apparatus, in which oxygen flow acts as the source of power and provides oxygenation for the perfused myocardium. Ten adult porcine hearts which had been preserved for 24 hours were resuscitated successfully and continued to beat steadily for more than 1.5-3 hours after reperfusion. Myocardial ultrastructure was observed at the end of preservation and 15-120 minutes after reperfusion. The damages of the myocardial ultrastructure at the end of preservation were reversible.

Animals↗
PubMed1991

Foot pressure distribution during walking and shuffling.

The insensate foot is vulnerable to tissue damage from areas of repetitive, excessive pressures. It has been previously stated that a shuffling gait with short steps would increase the period of foot flat and thus minimize any excessive local plantar pressures. This theory was quantitatively evaluated with a portable, in-shoe pressure data-acquisition system. Seven pressure sensors were located in the left and right insoles under the metatarsal heads, hallux, and posterior and anterior heels. Plantar pressure data were acquired from ten able-bodied subjects during four minutes of continuous shuffling and walking at a metronome-controlled cadence. Peak pressures, foot-to-floor contact durations, and pressure-time integrals under each sensor during shuffling and walking were analyzed and compared. Peak pressures were decreased at all sensor sites during a shuffling gait. The greatest decreases were noted at the first and second metatarsals (up to 57.8%) and hallux (up to 63.2%). A 41.6% decrease in overall summated peak plantar pressures during shuffling was found. Foot-to-floor contact durations during shuffling were increased from 22.0% to 76.9% at all 14 sensor locations. Pressure-time integrals during shuffling were increased at the heels (up to 78.9%) and decreased at the metatarsal heads and great toes (up to 26.7%). There was a 3.3% increase in the overall summated pressure-time integral during shuffling. Our findings are consistent with the hypothesis that a shuffling gait increases the period of foot flat and the area of weight bearing, resulting in lower peak plantar pressures on any one area.

Adult↗
PubMed1990

An umbilical data-acquisition system for measuring pressures between the foot and shoe.

We have developed an umbilical data-acquisition system for measuring pressures between the foot and shoe during walking. It consists of pressure sensors in the insoles of shoes, amplifier circuits, umbilical cables, an analog-to-digital converter, and a graphics display card in an IBM PC for real-time data collection and display. The applied pressure on a sensor decreases its resistance, which causes the output voltage of the amplifier circuit to increase. We attach seven sensors to the surface of each insole of a pair of extra-depth shoes and calibrate all the sensors in the insole before and after each test using a load cell as a reference. The IBM PC samples the outputs from the sensor and the load cell and stores a piecewise linear lookup table for use in compensation for the nonlinearity of the sensor. On the PC's graphics display, two programs provide displays of foot pressures as real-time bar graphs or as analog pressure versus time curves.

Analog-Digital Conversion↗
PubMedDate not supplied

A noninvasive diagnostic method for aortic regurgitation by detecting carotid blood flow with bidirectional Doppler ultrasound.

This paper reports a safe, noninvasive and accurate method for estimating aortic regurgitation. It is possible to detect some quantitative features of the disease from the velocity information obtained from the common carotid artery with the bi-directional velocimeter (model F1) developed by the authors. The diastolic murmur over the aortic region is a quantitative feature of the disease. With the theory of quantification I, both qualitative and quantitative variables were processed. A prediction formula was obtained to assess the degree of aortic regurgitation. The results of such predictions in 15 normal subjects and 25 patients are given. All the patients underwent retrograde aortography or operation to provide comparison with the ultrasonic measurements.

Adult↗