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Biomedical subjects

F Ma

Publications and source records attributed to F Ma.

At least 55 records · Page 3Linked to original sources
PubMed1997

Determination of cocaine and its metabolites in serum microsamples by high-performance liquid chromatography and its application to pharmacokinetics in rats.

A single-solvent extraction step high-performance liquid chromatographic method is described for quantitating cocaine and its three metabolites in rat serum microsamples (50 microl). The separation used a 2.1-mm I.D. reversed-phase Brownlee C18 column with an isocratic mobile phase consisting of methanol-acetonitrile-25.8 mM sodium acetate buffer, pH 2.2, containing 1.29-10(-4) M tetrabutylammonium phosphate (12.5:10:77.5, v/v/v). The detection limit was 2.5 ng/ml for all the compounds using an ultraviolet detector operated at 235 nm. The method was used to study the pharmacokinetics of cocaine after an intravenous (i.v.) bolus dose (4 mg/kg).

Animals↗
PubMed1997

[Senility-preventing effect of erlingcankang decoction].

Experiments with Erlingcankang Decoction showed that when given to silk worms it could noticeably prolong the growth period of larvae and raise an average of 10-day survival of the male moths; when given to mice it could prolong their life; and when given to on old rats it could markedly raise the contents of SOD in the liver and red cells, lower the content of MAO-B in the brain, LF in the brain and adrenal gland and also LPO in the liver.

Aging↗
PubMed1997

Evaluation of transforming growth factor beta and bone morphogenetic protein composite on healing of bone defects.

OBJECTIVE: To evaluate the effect of transforming growth factor-beta/bone morphogenetic protein (TGF-beta/BMP) composite on the healing of large segmental bone defects and to discuss the interaction between TGF-beta and BMP during bone repair. METHODS: A 1.5 cm segmental defect was made in the mid-upper part of the radial shaft of 48 adult rabbits. The defects were filled with implants of TGF-beta/carrier, BMP/carrier or TGF-beta/BMP/carrier separately. 120 micrograms of purified bovine TGF-beta and 12 mg of BMP were used in the composite. The defects were examined radiographically and histologically at 4, 8, 12 and 16 weeks post-operation. RESULTS: In the group filled with TGF-beta/BMP composite, the defect areas were bridged at 4 weeks, with callus of uniform radiodensity. Cortices of the cut ends were obscured by new bone. By 16 weeks post-operation, the defects were bridged by uniform new bone and the cut ends of the cortex could not be seen in all groups. In group of BMP/carrier, the defects were filled with more irregular woven bone callus than in other two groups. TGF-beta/BMP implanted defects in animals killed at 16 weeks showed histologically new lamella and woven bone that was formed in continuity with the cut ends of the cortex. Medullar canal was recanalized and contained marrow elements with normal appearance. CONCLUSIONS: These data demonstrate not only the synergistic action between TGF-beta and BMP in the process of bone healing, but also a better effect of TGF-beta/BMP composite than single TGF-beta or BMP on bone repair, especially in the early stage of bone repair process.

Animals↗
PubMed1996

Determination of midazolam and its metabolites in serum microsamples by high-performance liquid chromatography and its application to pharmacokinetics in rats.

A single-solvent extraction step high-performance liquid chromatographic method is described for quantitating midazolam and its two hydroxy metabolites in rat serum microsamples (50 microliters). The separation used a 2 mm I.D. reversed-phase Symmetry C18 column with an isocratic mobile phase consisting of methanol-acetonitrile-14.9 mM sodium acetate in water at pH 3.0 (10:23:67, v/v). The detection limit was 10 ng/ml for all the compounds using an ultraviolet detector operated at 230 nm. The method was used to study the pharmacokinetics of midazolam after an intravenous bolus dose (0.75 mg/kg).

Animals↗
PubMed1996

Osteochondrogenic potential of marrow mesenchymal progenitor cells exposed to TGF-beta 1 or PDGF-BB as assayed in vivo and in vitro.

Mesenchymal progenitors cells can be isolated from rat bone marrow and mitotically expanded in vitro. When these cells, which we operationally call mesenchymal stem cells (MSCs), are placed in an appropriate environment, they have the capacity to differentiate into bone and/or cartilage. This capacity is called osteochondrogenic potential. In this study, preconfluent MSCs were exposed in vitro to 5 ng/ml transforming growth factor-beta 1 (TGF-beta 1) or platelet-derived growth factor, isoform BB (PDGF-BB) for a pulse of 48 h and assayed for cell proliferation, alkaline phosphatase activity, and osteochondrogenic potential; untreated MSC's served as controls. In these cell culture conditions, TGF-beta 1 or PDGF-BB had similar effects on proliferation and alkaline phosphatase activity. Both growth factors increased cell proliferation and decreased alkaline phosphatase activity of MSCs. Sister cultures of TGF-beta 1- or PDGF-BB-treated MSCs and untreated MSCs were trypsinized. For each type of culture, the trypsinised MSCs were split in two parts: one part was replated in an osteogenic medium to assess its in vitro osteogenic potential, whereas the other part was seeded into porous calcium phosphate ceramics and implanted subcutaneously in syngeneic rats to assess its in vivo osteochondrogenic potential. PDGF-pretreated MSCs showed no difference in in vivo and in vitro osteochondrogenesis from that of control MSCs, while TGF-beta 1 pretreatment blocked the osteochondrogenic potential of MSCs when assayed in vitro for bone nodule formation. However, when tested in vivo, TGF-beta 1-pretreated MSCs were able to form bone and cartilage. These data show that measurements of proliferation and alkaline phosphatase activity of preconfluent MSCs immediately after exposure to growth factor were not predictive of their subsequent osteochondrogenic potential. Moreover, the variation of the osteochondrogenic potential of MSCs after exposure to growth factor was further modulated by the environment in which the MSCs were assayed.

Alkaline Phosphatase↗
PubMed1996

Pharmacokinetics and bioavailability of midazolam after intravenous, subcutaneous, intraperitoneal and oral administration under a chronic food-limited regimen: relating DRL performance to pharmacokinetics.

The effects of midazolam on animal behavior often are evaluated under a chronically food-limited regimen, which is used to implement food-reinforced performance, but the corresponding pharmacokinetics are lacking. The present study investigated the pharmacokinetics of midazolam after i.v., s.c., i.p., and p.o. administration in food-limited rates. A two-compartment model best described the concentration-time profiles for the four routes of administration. The rate of midazolam absorption was rapid, and peak concentrations were attained in less than 7 min for the three extravascular routes. The mean volume of distribution of the central compartment and clearance were 0.77 l/kg and 2.03 l/h per keg, respectively. Midazolam elimination half-lives for the four routes of administration ranged from 23.1 to 49.5 min, and metabolites could not be detected. The mean absolute bioavailability was route-dependent: 39.3% (s.c.) 19.2% (i.p.) and 4.6% (p.o.). The markedly low oral bioavailability found in food-limited rats contrasted to the value reported for free-feeding rates (45%). Although the i.p. route yielded the highest maximum concentration on occasion, serum midazolam concentration-time profiles were variable, but did correspond to respective sedative responses. DRL 45-s performance after s.c., i.p., and p.o. administration further supported the advisability of using the s.c. route of administration, as opposed to the i.p. route, for studying midazolam dose-response relations. The bioavailability values assessed from DRL performance also agree with the measured pharmacokinetic values.

Administration, Oral↗
PubMed1996

Role of transforming growth factor beta (TGF-beta) in repairing of bone defects.

TGF-beta is a multifunctional cytokine that regulates many aspects of cellular function, including periosteal mesenchymal cell proliferation, differentiation. This experiment is to study its effects on bone defect repair. A rabbit radial bone defect model was used to evaluate the effect of TGF-beta, which was extracted and purified from bovine blood platelets, on the healing of a large segmental osteoperiosteal defect. A 1.5-centimeter segmental defect was created in the mid-upper part of the radial shaft of adult rabbits. The defect was filled with implant containing TGF-beta that consisted of carrier and bovine TGF-beta. Limbs served as controls received carrier alone. The defects were examined radiographically and histologically at 4, 8, 12, 16 and 20 weeks after implantation. The results showed that in TGF-beta implant group, the defect areas at 12 weeks post operation were bridged by uniform new bone and the cut ends of cortex could not be seen; while in control group, the defects remained clear. Only a small amount of new bone formed as a cap on the cut bone ends. In the experimental group, new lamellar and woven bone formed in continuity with the cut ends of the cortex. An early medullar canal appears to be forming and contained normal-appearancing marrow elements; while the control group displayed entirely fibrous tissue within the defect site. Remnants of the cancellous bone carrier were observed in the control specimen. These data demonstrate that exogenous TGF-beta initiate osteogenesis and stimulate the bone defects repair in animal model.

Animals↗
PubMed1996

[An X-ray study of the density and orientation of the cutaneous arteries in the lower leg].

Angiography was performed on 10 legs of fresh cadavers to investigate the density and orientation of small arteries of the lower leg. It was revealed that there were more vertically arranged arteries than the horizontally arranged ones in the skin and superficial fascia. The entire surface of the lower leg was divided into 9 regions. The density of arteries of different orientations in the skin and fascia was measured regionally. Though the density of different regions had a significant difference, no statistical significant difference was found in vessel anastomosis rate between different regions. Where the density was high, the anastomoses were rich. According to these findings, suggestions for the design of random flaps in the lower leg were discussed.

Adult↗
PubMed1995

Oral and IP caffeine pharmacokinetics under a chronic food-limitation condition.

For food-limited rats, serum caffeine was proportional to IP caffeine doses (10-40 mg/kg) for Cmax and area under the curve [AUC(0-24 h)], whereas the three dimethylxanthine (DMX) metabolites of caffeine were disproportional over the dose range. Steady-state concentrations of caffeine and the three metabolites were evident at the 11th day of chronic, daily caffeine IP 20 mg/kg doses. Both caffeine and the three metabolites were dose proportional for Cmax and AUC(0-24 h) by schedule-induced oral caffeine self-administration within the dose range taken (9-38 mg/kg). These results contrast with the nonlinear kinetics of caffeine reported for rats under ad lib conditions. Elimination rate constants (Kel) remained the same for the two routes, but apparent volume of distribution (AVd) and clearance (Cl) were different. The order of the Kel values was caffeine > paraxanthine > theophylline > theobromine. The effects of linear vs. nonlinear caffeine pharmacokinetics may have distinct implications for the resulting pharmacodynamics.

Administration, Oral↗
PubMed1995

[An epidemiologic study on pulmonary fibrosis caused by hard alloy dust].

A cross-sectional study, with 1,237 employees solely exposed to hard alloy dust and 502 controls in four hard metal works and two tool and grinder manufacturers in China, was conducted. Results showed prevalence of symptoms of respiratory system, and abnormalities in lung function and serum level of ceruloplasmin and urine cobalt content in exposed group were significantly higher than those in controls. Eight cases of pneumoconiosis were detected by chest X-ray films with a prevalence of 0.65% and an average length of employment in dust environment of 25.2 years. It suggested hard alloy dust could cause pulmonary fibrosis and pneumoconiosis in exposed workers.

Alloys↗
PubMed1995

Induction of osteogenesis by bovine platelet transforming growth factor-beta (TGF-beta) in adult mouse femur.

TGF-beta has been shown to be one of the most important regulators in chondrogenesis and osteogenesis. Daily subperiosteal injection of TGF-beta, which was extracted and purified from bovine platelets, into adult mouse femur resulted in proliferation and differentiation of the mesenchymal cells, chondrogenesis, and endochondral osteogenesis. After cessation of the injection, the endochondral ossification occurred widely, resulting in replacement of the cartilage with new bone. These phenomena demonstrate that exogenous TGF-beta stimulates mesenchymal proliferation and differentiation that occur in early fracture healing and suggest the possibility of clinical application of TGF-beta for fracture repair and bone transplantation.

Animals↗
PubMed1995

[Observation of cristae of posterior ampullae with laser Doppler].

UNLABELLED: To set up the methodology of measuring vestibular blood flow was the key to the study of vestibular microcirculation. 10 guinea pigs' posterior ampullae cristae blood flow were measured with Laser Doppler Flowmetry. RESULTS: cochlear flow was 318.39 +/- 91.66mV. Cristae of posterior ampullae was 194.00 +/- 45.26mV. The arterial blood pressure was stable in 9.99 approximately 10.27kPa. The present results showed cochlear and vestibular blood flow were 62.14% and 37.86% in total inner ear blood circulation. The latter appeared to be about one half of cochlear blood flow. These suggested that the blood flow of posterior ampullae can reflect the blood flow of vestibular to some degree. Laser Doppler was technically simple, non-invasive, highly stable, reproducible and sensitive.

Animals↗
PubMed1992

Interferon-gamma inhibits proliferation, but not commitment, of murine granulocyte-macrophage progenitors.

We investigated the effects of interferon gamma (IFN-gamma) on the growth of murine hematopoietic progenitors. IFN-gamma inhibited granulocyte colony-stimulating factor (G-CSF)- and interleukin-3 (IL-3)-dependent colony growth by granulocyte-macrophage (GM) progenitors derived from the bone marrow cells of normal mice. However, the number of IL-3-dependent GM colonies formed by the bone marrow cells of 5-fluorouracil (5-FU)-treated mice was not influenced by the addition of IFN-gamma. Replating experiments suggested that IFN-gamma suppressed GM colony growth directly and that it exerted an inhibitory effect on the proliferation, but not on the commitment, of GM progenitors. In contrast, IFN-gamma failed to suppress colony growth by mast cell progenitors. Erythroid and megakaryocytic progenitors exhibited different responses to IFN-gamma depending on mouse strains. These results suggest that potent negative regulators are not always inhibitors of hematopoietic progenitors.

Animals↗
PubMed1992

[Effect of CCK receptor antagonists on plasma CCK bioassay].

Fasting and postprandial plasma CCK levels of 102 normal subjects were measured by bioassay with dispersed rat pancreatic acini. The reference values ranged from 0 to 4.2 pmol/L (CCK-8 equivalents) for fasting and from 1.1 to 13.5 pmol/L for postprandial state. There was no significant difference between male and female, or in different age groups. The effects of CCK receptor antagonists of 3 different categories on CCK bioactivity in plasma measured by the bioassay were investigated. L 364,718 (5 nmol/L), proglumide (1.0 mmol/L), or Bt2-cGMP (0.1 mmol/L) was either extracted by SEP-PAK C18 cartridges together with human plasma containing 8 pmol/L of CCK-8, or added into the plasma extracts before the assay. The CCK bioactivity was inhibited by all of the 3 CCK antagonists. The action of L364,718 could be eliminated by the procedure of plasma extraction, but not of proglumide or Bt2-cGMP. It was suggested that CCK bioassay can be used even if L364,718 was administered. However, CCK cannot be measured accurately if there are proglumide or Bt2-cGMP in the plasma.

Adolescent↗
PubMed1991

[Pharmacological study on anti-hepatitis effect of Cotinus coggygria Scop. Syrup].

This paper shows that the Cotinus coggygria syrup has the effect of protecting the liver from chemical damages, reducing tension of the choledochal sphincter, increasing the bile flow and raising the body immunity. The anti-hepatitis effect may be carried out through decreasing transaminase, normalizing functioning of the gallbladder, reducing icterus and enhancing the immunity of the body.

Animals↗