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AIM: To observe the effects of folic acid (FA) on antioxidant enzyme, nitric oxide synthase (NOS) and nitric oxide (NO) in ovariectomized (OVX) rats.METHODS: Forty three-month-old female SD rats were randomly divided into 5 groups:sham group, OVX group, diethylstilbestrol group (0.03 mg· kg-1· d-1), low-dose FA group (5 mg· kg-1· d-1) and high-dose FA group (20 mg· kg-1· d-1).Gastric gavage started 1 week after operation and lasted for 10 weeks.The rats in sham group and OVX group were given distilled water instead of FA as controls.At the end of the 10th week, the L5 vertebra and right femur were removed for determination of bone mineral density (BMD).The bone homogenates were made using the L3 and L4 vertebrae.The levels of the total antioxidant capacity ( TAC) , glutathione peroxidase ( GSH-Px) , malondialdehyde ( MDA ) , NOS and NO were detected in plasma and bone homogenates.RE-SULTS:Compared with sham group, the BMD levels in L5 vertebra and right femur and the levels of GSH-Px and NO in the plasma were all decreased.The levels of TAC, GSH-Px, NOS and NO in the bone homogenates were also decreased, while the MDA concentration was increased in OVX group (all P<0.01).Compared with OVX group, the levels of TAC, GSH-Px, NOS, NO and BMD of the L5 vertebra and right femur were all increased, while the MDA concentration was de-creased in high-dose FA group (all P<0.01).CONCLUSION:In female SD rats, ovariectomy leads to a significant re-duction of antioxidant enzyme, NOS and NO levels.Oxidative stress is possibly involved in the development of osteoporo-sis.Protection against osteoporosis by high-dose FA may be linked to improvement of antioxidant enzyme activity, the levels of NOS and NO as well as a reduction of oxidative stress in ovariectomized rats.
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BACKGROUND:Hydrophobic acrylic foldable intraocular lens should be evaluated biologicaly with New Zealand rabbits as implant objects prior to clinical trial. OBJECTIVE:To observe the biological safety of hydrophobic acrylic foldable intraocular lens. METHODS: Twelve New Zealand rabbits were enroled. The right eyes were implanted with self-developed hydrophobic acrylic foldable intraocular lens (Shenyang Baiao Medical Device Co., Ltd., China) as experimental group, and the left eyes were implanted with Acrysof IQ SN60WF (Alcon, USA) as control group. RESULTS AND CONCLUSION: After implantation, there were no significant differences in the cornea, anterior chamber, implant position, posterior segment of eyebal between two groups. Tissue proliferation had no obviously difference between the two groups, and there were cornea and lens pouch inflammations. No macrophages and other inflammatory cels were visualized on the surface of intraocular lens, and fibrous tissues were found on the intraocular lens surface and in the haptics root. These findings suggest that the self-developed hydrophobic acrylic foldable intraocular lens has no difference from Acrysof IQ SN60WF widely used in clinic, and it has the biological safety.
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BACKGROUND:At present, the copper-bearing intrauterine device, a kind of class III medical devices, is commonly used in China. However, there is no clear conclusion about whether it has impact on the embryo or fetus in some cases, such as unexpected pregnancy during long-term implantation and pregnancy in a short time after removing it. OBJECTIVE: To evaluate the safety of copper-bearing intrauterine device by observing the influence of copper-bearing intrauterine device extracts on pregnant rats and rat fetuses by tail vein injection in the sensitive period of teratogenesis. METHODS: A total of 60 fertilized rats were divided into control group, high dosage group, middle dosage group, and low dosage group. The copper-bearing intrauterine device extracts were prepared by the continuous extraction method. Different concentrations (0.2, 0.1, 0.05 g/mL) of copper-bearing intrauterine device extracts were injected by the tail vein at the 1st day of pregnancy in the latter three groups at a dosage of 0.01 mL/g per day. The control group was given the same amount of normal saline. The injection lasted for 20 days. Then, the pregnant rats were sacrificed to measure body mass, check both sides of the uterus and internal organs, isolate fetal rats, as wel as record the quality of uterus and fetal rats, corpus luteum, implantation numbers, the number of stilbirths, then number of live births and the number of fetal absorption. The fetal rats were determined in the folowing aspects: body mass, body height, tail length, the ossification degree and appearance of the occipital bone, bone and visceral anomalies. RESULTS AND CONCLUSION: The number of births, implantation numbers, the number of live births, the number of corpus luteum, the percentages of live births and stilbirths, the number of resorbed fetuses, and the weight of uterus and fetal rats in the control group showed no difference from those in the other three groups (P > 0.05). No malformation in the internal organs occurred. Compared with the control group, the high, middle and low dosage groups showed no difference in the height, tail length, body mass, and ossification degree of the occipital bone of fetal rats (P > 0.05). No malformation in the appearance, skeleton and internal organs occurred in the fetal rats. These findings indicate that there were no maternal toxicity, abnormal embryonic growth or rat fetus anomalies after injecting copper-bearing intrauterine device extracts into pregnant rats in sensitive period of teratogenesis.
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BACKGROUND:The osmotic tissue expander is a self-fil ing device consisting of an osmotic active hydrogel which is made of vinylpyrrolidone and mehtylmethacrylate. It can absorb body fluids and swel up gradual y after embedded. OBJECTIVE:To explore the short-term and long-term regular patterns as wel as histocompatibility of the osmotic tissue expander in vivo. METHODS:A self-control design was carried out in Wistar rats by embedding the osmotic tissue expander and high-density polyethylene into each side of their spinal column subcutaneously. Wound healing, tissue expansion and inflammatory reaction were detected and compared at different periods after operation. RESULTS AND CONCLUSION:Al the wounds got primary healing. The device expanded fastest at week 1 after the implantation. After being enlarged to about nine times that of the initial size at week 4, the expander slowed down its swel ing. It reached its ultimate volume at week 12 which was about 10 times as big as that of the initial one. Then it remained almost the same size until the end of our design. Pathological sections showed that the inflammatory reaction of osmotic-tissue-expander-group had no significant difference from that of the control group (P>0.05). These findings suggest that osmotic tissue expander has a slow-lasting swel ing ability and good histocompatibility.
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BACKGROUND:In the cytotoxicity test of the mussel adhesive protein dressing for wound healing, because of positive charge properties of the protein, when extracting ratio is 1:9, the cel s exhibit poly-group phenomenon that results in errors in the cytotoxicity test of mussel adhesive protein samples. OBJECTIVE:According to the existing standards, to improve the leaching proportion and pretreatment of mussel adhesive protein dressing for wound healing based on the special properties and working condition of mussel adhesive protein. METHODS:(1) Extract method:Extract solution of mussel adhesive protein dressing was prepared with mussel adhesive protein dressing and cel medium at extracting ratios of 1:9 and 1:131. Then, L929 cel s were cultured in extract solutions of mussel adhesive protein dressing, natural latex and high-density polyethylene, respectively. (2) Method of direct contact:Distil ed water, solutions of mussel adhesive protein dressing, dimethyl sulfoxide and cel medium were used to culture L929 cel s. RESULTS AND CONCLUSION:When the extracting ratio was 1:9, the cel s agglomerated which is not suitable for cytotoxicity test. When the extracting ratio was 1:131, flocculated sediment and cel aggregation disappeared, the cytotoxicity test results showed no cytotoxicity with higher reliability. Direct contact method showed the samples had no cytotoxicity. The extract method with adjusted extracting radio or direct contact method can be applied to test the in vitro cytotoxicity of mussel adhesive protein dressing for wound healing.
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BACKGROUND: The nano-hydroxyapatite/bacterial cellulose (nHAP/BC) nanocomposites has a good prospect of application in bone tissue engineering, and the bone tissue engineered materials and its degradation products Should have excellent compatibility. This study further assessed DAN synthesis cycle using flow cytometry on the basis of evaluating cell compatibility by metabolic 3-(4, 5-dim ethylthiazo 1-2-y 1) -2, 5-Dipheny 1-2H-tetrazolium (MTT) assay. OBJECTIVE: To evaluate the cytocompatibility of a new-pattern nHAP/BC nanocomposites and its residues. METHODS: Effects of nHAP/BC nanocomposites and its residues on morphclogicel changes in osteoblasts were observed using in vitro cell culture method. Effects of nHAP/BC nanocomposites and its residues on osteoblast growth and prclifera'don were evaluated by MTT assay. Cell cycle phase changes were detected using flow cytometry to evaluate matsdal effects on cell proliferation on molecular levels. RESULTS AND CONCLUSION: The nHAP/BC nanocomposites and its residues had neither remarkable effects on cell morphology, nor significant inhibition on osteoblast growth and proliferation. Test of MTT cytotoxicity showed that the average cell proliferation rate was over 80% after treated with the material and its residues, with the cytotoxity grade of 1 (non-toxic). Flow cytometry indicated that the rate of G_0/G_1 was reduced, and the rates of S, G2/M were increased, and the synthesis of DNA was increased, the cellular growth and repair in osteoblasts was accelerated. These indicated that nHAP/BC nanocomposites have good cytocompatibility, and it will be safe and prospected scaffolds in bone tissue engineering.
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The nutritional and food hygienic character of the new developed soy protein concentrate and soy protein isolate in Heilongjiang province were studied by chemical analysis and rat experiment. These products have not yet been reported in China. The results indicated that the content of protein of soy protein concentrate and isolate was 69.76 and 83.11%(as anhydr-ate basic), the PER 2.00 and 1.34, the apparent digestibility 77.54 and 85.72%, the true digestibility 84.33 and 93.19%, the biological value 79.80 and 62.54%, the NPU 67.39 and 58.28% respectively.The essential amino acid composition of the two samples was the same as the products prepared in the other countries. By the hematological and pathological examination in rats, the contents of serveral harmful substan- ces were allowable or not detected. The authors belived that the nutritional quality of the two soy protein products was nearly the same as those in other countries, and its food safety was satisfactory.
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One hundred and ten college students, 66 males and 44 females, were studied for the evaluation of vitamin C status by use of the ratio of reduced vitamin C to creatinine in a random urine sample. During the experimental period, the dietary source of creatinine was strictly abstained. After voiding in the morning, the volunteers were weighed and their urine were collected at the end of 1st, 2nd, 4th, 8th, 12th and 24th hr respectively. The contents of reduced vitamin C and creatinine in each collected urine sample were analysed, and then the total amounts in 24 hrs were calculated.The experimental results showed:1. The distribution of the creatinine excretion in 24 hrs was nearly constant.2. The percentage of reduced vitamin C excretion per hour to the total 24 hrs excretion was similar in subjects of different vitamin C status and was lowest in 12 hrs of night urine. A curvilinear regression was given for the percentage of reduced vitamin C excretion in relation to the time.3. The ratio of reduced vitamin C (as mg) to creatinine (as gm) and the ratio of reduced vitamin C to creatinine (as mg) per body weight (as kg) were calculated from their contents in 12 hrs urine in those who exc- reted reduced vitamin C in urine less than 80 mg in 24 hrs. The relationship between these two ratios and the excretions of reduced vitamin C in 24 hrs urine was studied and four equations of curvilinear regressions were given.4. According to these equations, the correlated values of vitamin C/ crcatinine and vitamin C/creatinine/body weight in random urine samples in respect of four different grades of vitamin C excretion of 24 hrs urine were recommended.It was shown to be a new simplified method for evaluating the nutritional status of vitamin C in human body. The practical aspect of its application was discussed.
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The apparent digestibilities of two preparations of corn as staples in men were estimated during March and April in 1979. Seven healthy adult men, who lived in this region for many years, were accustomed to eat corn as their staple diets. Each of the two preparations from the same batch of corn was used in the experiment. One preparation was "cooked corn meal" and the other was Jian-bing, the latter was considered the better way of cooking. Other ingredients of food in these two test diets were the same. During the test periods, the volunteers ate the test diets and drank boiled water ad lib, but the quantities were recorded. No other foodstuffs and drinks were allowed. The nutritive values of test diets were sufficient to meet the subjects' physiological needs. The 12 days period was divided into adaptative and testing periods of three days each for the two kinds of test diets. During the test periods, the total foodstuffs and the volunteers' faeces were analysed for the contents of water, anhydrates, total ni- trogen, crude fat, ash and fiber in the samples. From the data obtained, the apparent digestibilities of anhydrates, total nitrogen and crude fat ware calculated. Urine nitrogen was analysed and the nitrogen balance was calculated. The body weight at the beginning and the end of test periods were measured.The apparent digestibility (%) of anhydrates was 93.31?0.393 and 94.79 ? 0.578, total nitrogrn 84.60 ? 0.843 and 87.77 ? 1.080 and crude fat 86.32 ? 1.296 and 94.68 ? 0.838 in cooked corn meal diet and the corn flour Jian-bing diet respectively. The apparent digestibility in corn Jian-bing diet was higher statistically than that of cooked corn diet. Body weights fluctuated within the normal range. The nitrogen balances of all subjects were positive and the difference of nitrogen balance studies between the two test diets was not statistically significant.The results of the experiment suggest that, the differences of apparent digestibility between two diets was mainly due to the methods of preparation, Jian-bing being better than cooked corn diet in human nutrition.