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Biomedical subjects

C P Lin

Publications and source records attributed to C P Lin.

At least 127 records · Page 7Linked to original sources
PubMed1989

A model to induce scattered cell damage in the corneal endothelium.

A model to induce scattered cell damage in the corneal endothelium was set up by shaking a pig cornea in a glass bottle with 0.18% NaCl. Disseminated endothelial-cell losses, whose amounts correlated with the durations of treatment, were observed in the corneas which were shaken for less than 8 min. Following organ culturing for 1 week, most of the corneas still possessed intact endothelia which means that even after the treatment the endothelium still keeps a normal regenerative ability. With this method of design, a good model is provided to study the regeneration of the corneal endothelium.

Animals↗
PubMed1989

[Solvent action of sodium hypochlorite on fresh and formalin fixed tissue: a biochemical approach].

Debridement of the root canal system has long been recognized as the critical phase of success in endodontic therapy. Because of the morphological complexity of most root canals, complete removal of the pulp tissue during the mechanical preparation of these root canals is often impracticable. Sodium hypochlorite is thus currently favored by most endodontists as the routine irrigant on account of its antimicrobial action and its capacity to dissolve fresh tissue together with necrotic tissues. Formocresol is another common medicament for endodontic treatment and is usually used for pulpotomy, pulpectomy and intracanal medication. Nevertheless, it was empirically believed that formocresol may interrupt the action of sodium hypochlorite in the dissolution of residual tissue. Therefore, the present study was undertaken to testify whether formocresol can substantially retard the solvent action of sodium hypochlorite by comparing the effectiveness of 5% sodium hypochlorite on fresh and formalin-fixed tissues. Connective tissue from the abdominal wall of Sprague-Dawley rats was cut into pieces weighing 0.05 g and measuring about 2 x 10 x 10 mm. A total of 20 pieces of tissue were collected and divided into two groups: 10 pieces were used immediately as the fresh-tissue group; the other 10 pieces were fixed in 10% formalin for 7 days as the fixed-tissue group. Each group was then immersed in 5 ml of 5% sodium hypochlorite for 60 seconds, and 1 ml was aspirated from each for assay. Dialysis was performed using 2 liters of double distilled water for a period of 4 hours with the water changed hourly.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Size and genetic composition of long terminal repeat sequences in the mouse intracisternal A-particle gene 81.

The intracisternal A-particle (IAP) genome is a retrovirus-like gene family. Over 1000 copies of IAP genes are dispersed throughout the mouse genome. The purpose of this study was to determine the nucleotide sequence of both ends of the long terminal repeat (LTR) units which bind the IAP gene 81. The results obtained showed that, whereas the structural domain and several genomic characteristics of the IAP 81 LTR units and other LTR structures of a given IAP gene were almost identical, the nucleotide sequences of these LTR units associated with different IAP gene were sometimes very different from each other. In the comparisons of different LTR structures, the transcriptional signals for promotion, initiation, polyadenylation and termination as well as several characteristic sequences of the Z-DNA region, enhancer core sequence and glucocorticoid-responsive element were all found to be present in IAP 81 LTRs. The possible roles of the primary nucleotide sequence of an LTR structure are discussed.

Animals↗
PubMed1987

Nucleotide sequence analysis of cellular flanking regions of intracisternal A-particle gene 81.

The cellular nucleotide sequences flanking the mouse intracisternal A-particle gene 81 were determined. The results indicated that they were made of many small oligonucleotide repeats both direct and indirect in orientation. These two different kinds of repeating sequences were often found to be overlap. The overall base composition of this region is relatively A + T rich. The most important feature of the sequences determined was that it consists of several repeated dinucleotide tracts containing a (CA)16 repeating cluster in the 5' end flanking region of one strand and another repeating dinucleotide cluster, (GT)16, in the 3' end flanking region of the same strand of this gene. In addition, the existence of two clusters of 9 continuous 5-bp repeat units, GCTTT, was found in the 3' end flanking region. The possible roles of such repeating sequence were discussed.

Animals↗
PubMed1987

In vitro detection of plant mycoplasmas by immunofluorescent staining with monoclonal antibodies.

Hybridoma techniques have been applied to develop specific monoclonal antibodies (McAbs) against spiroplasmas and mycoplasma-like organisms (MLOs). Advantages of the McAbs have been clearly demonstrated in the detection of aster yellows (AY) MLO by indirect enzyme-linked immunosorbent assay (ELISA) and immunofluorescent staining, compared with conventionally produced polyclonal antibodies. McAbs have also been applied in the in vitro detection and identification of spiroplasmas and AY MLOs on membrane filters using modified direct-count immunofluorescent staining. Organisms were fixed with glutaraldehyde and treated with McAbs and fluorescein isothiocyanate (FITC)-conjugated antimouse immunoglobulin, by incubating and concentrating them in a microcentrifuge tube before collecting them on polycarbonate membrane. This procedure best conserves the helical integrity of spiroplasmas without altering the configuration of surface antigens recognized by McAbs. This method could be valuable in monitoring the fastidious mycoplasmas during purification or cultivation attempts.

Antibodies, Bacterial↗
PubMed1986

Comparison of control diets containing various protein levels for determining net protein utilization by rats.

The objective of this study was to explore the commonly used method of Miller and Bender for determination of the net protein utilization (NPU). Eight test diets of different protein quality from both animal and vegetable sources were studied at 10% protein level with the protein content of the control diets being 0, 1, 2, 3 or 4% whole egg protein. At the end of the 10-d feeding period body nitrogen of the rat carcasses (test and control groups) was analyzed. Comparison of the body weight was also made. Rats fed either 2 or 3% egg protein maintained initial body weight and body nitrogen at the end of the feeding period. The absence of a significant difference between the NPU values of the test proteins calculated with the 1, 2, 3 or 4% egg protein group as the control and the NPU values obtained by the method of Miller and Bender (which uses the protein-free group as the control) demonstrated that the relative nutritive value for different proteins could be correctly determined by the traditional NPU method.

Animals↗
PubMed1983

[Determination of malignancy of cartilaginous tumors (2). Determination of malignancy by nuclear DNA contents and their distribution patterns in cartilaginous tumors].

In 40 different types of cartilaginous tumors, the number of binuclear cells was calculated and DNA content was examined using fluorescent Feulgen cytophotometric technique. In 7 enchondromas and 1 synovial chondromatosis, the DNA content was diploid in 7 and hypotetraploid in 1, and showed a unimodal normal distribution. The number of binuclear cells was 0.1-0.45%, and the mean DNA content was below 4. These cases showed no evidence of disease after curettage and bone graft. The follow-up period was from 4 years 6 months to 7 years 1 month, averaging 6 years 2 months. In 2 enchondromatoses and 2 benign chondroblastomas, the DNA content was diploid and showed a unimodal normal distribution. One chondromyxoid fibroma showed a broad-unimodal tetraploid distribution, and one benign chondroblastoma showed a broad-aneuploid distribution. The nuclear DNA content was sometimes histologically similar to that of chondrosarcoma in some benign cartilaginous tumors. In 5 secondary chondrosarcomas, the DNA content was hypo- or hypertetraploid, hexaploid, and showed broad-unimodal or broad-bimodal distribution. The number of binuclear cells was from 13% to 23%. Although the size of the nucleus was small, the number of binuclear cells was evidently numerous. The preferred treatment for secondary chondrosarcoma is principally wide resection, but amputation is sometimes indicated in cases of recurrence and large tumor size. The follow-up period was from 2 years 2 months to 18 years 11 months, averaging 9 years 11 months. All 5 patients were surviving at the time of follow-up. The DNA content in chondrosarcoma was mostly hypo- or hypertetraploid, hexaploid, or octaploid and showed broad-unimodal, broad-bimodal or broad-aneuploid distribution. The number of binuclear cells was 0.55-3.5%. The mean DNA content was proportional to the number of binuclear cells, the positive correlation between the mean DNA content and the number of binuclear cells was found (p less than 1%).

Adolescent↗
PubMed1982

Protein requirements of young Chinese male adults on ordinary Chinese mixed diet and egg diet at ordinary levels of energy intake.

With a total of 28 normal, healthy male adults, N balance studies with both Chinese mixed diet and egg diet were conducted at four protein levels with the former (0.45, 0.55, 0.65 and 0.75 g . kg-1 . day-1) and at three protein levels with the latter (0.35, 0.45 and 0.55 g . kg-1 . day-1) at ordinary levels of energy intake. By regression analysis, the mean maintenance N requirement (PRm) of the mixed Chinese diet calculated was 127.0 mg . kg-1 . day-1 (0.79 g protein . kg-1 . day-1). Estimate a allowance for individual variation to cover the 97.5% population (PR0.975) was 188.1 mg . kg-1 . day-1 (1.18 g protein . kg-1 . day-1). As for the egg diet series, PRm and PR0.975 were 98.2 mg N . kg-1 . day-1 (0.61 g protein . kg-1 . day-1) and 141.6 mg N . kg-1 . day-1 (0.89 g protein . kg-1 . day-1), respectively. Net protein utilization (NPU) of egg diet protein was significantly higher than that of the Chinese mixed diet protein (P less than 0.01), with mean values of 56 versus 43. True digestibility of the mixed diet and egg diet proteins was 96.5 and 98%, respectively. The efficiency of utilization of the Chinese mixed diet protein was 73-77% of the egg protein, based on relative N requirements.

Adult↗
PubMed1982

Actual nitrogen deposition in mature adult rats fed moderate to high protein diets.

Comparison between the positive N balance data and the actual N deposition in the same adult animals was made. In experiment 1, 24 mature 9-month old male rats were divided into three groups. One group was killed on day zero and served as the control. The two other groups were fed 25 or 49% casein diet for 8 weeks. Body weight was kept relatively constant by regulating the dietary intake. The N balance study (including body hair N loss) was conducted thrice intermittently, and body N was determined at the end of the experiment. It was found that the mean total-body N of the 49% casein groups was 967 mg higher than the 25% casein groups and 885 mg higher than the day-zero control group (P less than 0.01). The calculated N retention during the experimental period was 1876 mg for the 49% casein group. In experiment 2, a similar study was conducted except that the 25 and 49% casein diets were fed ad libitum, and body weight gain was allowed. The total-body N values of both test groups at the end of the feeding period were very close to each other, but significantly higher than that of the day-zero control group (P less than 0.01).

Animals↗
PubMed1981

Monomeric chlorophyll a enol: Evidence for its possible role as the primary electron donor in photosystem I of plant photosynthesis.

The chlorophyll a (Chl a) special-pair model of the primary donor of photosystem I (P700) does not account in a completely adequate fashion for the magnetic resonance properties observed for P700(+). Moreover, P700 is at least 420 mV easier to oxidize than is Chl a in vitro. Neither Chl a dimer formation nor selective ligation of Chl a can account for this potential difference. Enolization of the Chl a ring V beta-keto ester results in a very different pi electronic structure. The Chl a enol can be trapped as a silyl enol ether. In addition, the enol analog 9-desoxo-9,10-dehydro-Chl a can be prepared. Both the trapped enol and its 9-H analog are approximately 350 mV easier to oxidize than Chl a. The ESR spectrum of the cation radical consists of a single 6.1-G gaussian line that is line narrowed relative to that of Chl a(+) in a manner similar to P700(+). Electron-nuclear double resonance (ENDOR) spectroscopy resolves only a 3.5-MHz hyperfine splitting for the 3-methyl-group. The remaining splittings are all less than 3.5 MHz. The second moment of the ESR line of fully (13)C-enriched 9-desoxo-9,10-dehydro-Chl a(+) agrees with that of [(13)C]P700(+) to within 10%. Application of the special-pair model to the [(13)C]P700(+) second-moment data yields a 100% error. Ab initio molecular orbital calculations on ethyl chlorophyllide a enol cation bear out the ESR and ENDOR data. We conclude that a monomeric Chl a enol model provides a better description of the magnetic resonance parameters and oxidation potential of P700 than a Chl a special-pair model.

Journal Article↗
PubMed1980

Protein requirements of normal infants at the age of about 1 year: maintenance nitrogen requirements and obligatory nitrogen losses.

With 34 normal, healthy male infants aged 9-17 months, a total of 61 nitrogen (N) balance studies was conducted with N intake between 12 and 180 mg/kg/day. By regression analysis, the crude N maintenance requirements, either with whole egg or cow's milk protein, were estimated to be about the same, 106 and 103 mg/kg/day, respectively. The 97.5% confidence limits for the requirements were 128 (egg) and 142 (milk) mg/kg, respectively. Sums of the obligatory urinary and fecal N for the egg and milk protein series were 75 and 71 mg/kg as compared with 76 mg/kg of actually measured figure. Ratio of the maintenance N requirement to the obligatory N loss was 1.4. In another 15 N balance study, for which N intake from milk formulae ranged between 220 and 320 mg/kg/day, the mean apparent N retention was 25% of the intake. Total integumental N losses (skin + hair + nail) of infants fed 217-522 mg N/kg/day amounted to 7.8 +/- 2.9 mg/kg daily. Egg protein had somewhat higher digestibility than cow's milk protein, 92 versus 87%, but has lower biological value, 76 versus 82. Net protein utilization (NPU) estimated from the regression line was about the same for both proteins, 71 and 69, respectively.

Dietary Proteins↗