Biomedical subjects

C C Tsai

Publications and source records attributed to C C Tsai.

At least 19 recordsLinked to original sources

PubMed1998

Feasibility study of a natural crosslinking reagent for biological tissue fixation.

Bioprostheses derived from biological tissues must be chemically modified and subsequently sterilized before they can be implanted in humans. Various crosslinking reagents, including formaldehyde, glutaraldehyde, dialdehyde starch, and epoxy compound, have been used to chemically modify biological tissues. However, these synthetic crosslinking reagents are all highly (or relatively highly) cytotoxic. It is therefore desirable to provide a crosslinking reagent suitable for use in biomedical applications that is of low cytotoxicity and that forms stable and biocompatible crosslinked products. This study evaluates the feasibility of using a naturally occurring crosslinking reagent--genipin--to chemically modify biological tissues. Genipin and its related iridoid compounds, extracted from gardenia fruits, have been used in traditional Chinese medicine for the treatments of jaundice and various inflammatory and hepatic diseases. In this feasibility study, the cytotoxicity of genipin and the crosslinking characteristics of genipin-fixed biological tissues were investigated. Fresh porcine pericardia procured from a slaughterhouse were used as raw materials. Glutaraldehyde and an epoxy compound (ethylene glycol diglycidyl ether), which has been used extensively in developing bioprostheses, were used as controls. It was found that the cytotoxicity of genipin was significantly lower than that of glutaraldehyde and the epoxy compound. The amino acid residues in the porcine pericardium that may react with genipin were lysine, hydroxylysine, and arginine. Additionally, the genipin-fixed tissue had a mechanical strength and resistance against enzymatic degradation comparable to the glutaraldehyde-fixed tissue. This suggests that genipin can form stable crosslinked products. The results of this in vitro study demonstrate that genipin is an effective crosslinking reagent for biological tissue fixation.

Animals↗

PubMed1998

Biocompatibility study of a biological tissue fixed with a naturally occurring crosslinking reagent.

A recognized disadvantage of the currently available chemical reagents used to fix bioprostheses is the potential toxic effects a recipient may be exposed to from residues. It is therefore desirable to provide a crosslinking reagent that is of low cytotoxicity and can form stable and biocompatible crosslinked products. To achieve this goal, a naturally occurring crosslinking reagent-genipin-was used by our group to fix biological tissues. Genipin can be obtained from its parent compound geniposide, which can be isolated from the fruits of Gardenia jasminoides ELLIS. In our previous feasibility study, it was found that the cytotoxicity of genipin is significantly lower than both glutaraldehyde and an epoxy compound. Additionally, it was shown that genipin can form stable crosslinked products. The present study further investigates the biocompatibility of a genipin-fixed porcine pericardium implanted subcutaneously in a growing rat model. The fresh, glutaraldehyde-, and epoxy-fixed counterparts were used as controls. It was noted that the inflammatory reaction of the genipin-fixed tissue was significantly less than its glutaraldehyde- and epoxy-fixed counterparts. Also, the genipin-fixed tissue has tensile strength and resistance against in vivo degradation comparable to the glutaraldehyde-fixed tissue. Additionally, the calcium content of the genipin-fixed tissue measured throughout the entire course of the study was minimal. Nevertheless, further study in calcification for the genipin-fixed tissue should be conducted in a blood-contact environment. The results obtained in this subcutaneous study indicate that genipin is a promising crosslinking reagent for biological tissue fixation. However, further durability testing in vitro and in vivo are needed to determine the relative functional merits of this new crosslinker.

Animals↗

PubMed1998

Pair-rule gene runt restricts orthodenticle expression to the presumptive head of the Drosophila embryo.

Ectopic expression of the pair-rule gene runt in the anterior end of the Drosophila embryo antagonizes transcriptional activation of the head gap gene orthodenticle (otd) by the anterior morphogen bicoid. Here we investigate the relevance of runt's activity as a repressor of otd in normal Drosophila embryogenesis otd expression is activated in the posterior region of embryos that are mutant for runt. This posterior expression domain of otd depends on the activity of the orphan nuclear receptor protein Tailless. Repression of otd by runt does not require the conserved VVVRPY motif that mediates interaction between Runt and the co-repressor protein Groucho. The observed functional interactions between runt and tailless on otd expression may indicate there are other contexts where members of these two families of transcriptional regulators interact to regulate gene expression during development.

Animals↗

PubMed1998

Protein kinase C isoforms during the development of deciduomata in pseudopregnant rats.

In this study, we determined the expression of protein kinase C (PKC) isoforms during trauma-induced decidualization. The findings revealed that at least five PKC isoforms (alpha, delta, zeta, iota and lambda) were present in both control and decidualized tissues. After trauma-stimulation, PKC alpha was down-modulated in the deciduomata but not in the myometrium. Down-modulation was compatible with the increase in cell mitosis which reached a maximum at 2-3 days. On the other hand, PKC zeta was not down-modulated. It was increased both in the deciduomata and myometrium, and paralleled the frequency of decidual cell mitosis. The PKC isoforms of delta, iota and lambda were also increased, but they were associated with the depression of cell mitosis. Therefore, these findings suggested that the variable expression of PKC isoforms in trauma-induced decidualizing tissue in pseudopregnant rats may be involved in the modulation of decidual cell growth.

Animals↗

PubMed1998

Measurement of prostaglandin E2 and leukotriene B4 in the gingival crevicular fluid.

UNLABELLED: The arachidonic acid metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) are inflammatory mediators which are likely to be involved in the pathogenesis of periodontal disease. PGE2 mediates vasodilatation, increases vascular permeability, enhances pain perception by bradykinin and histamine, alters connective tissue metabolism and enhances osteoclastic bone resorption. LTB4 causes the accumulation of inflammatory cells in the inflamed sites, and degranulation of polymorphonuclear leukocytes. OBJECTIVE: To measure gingival crevicular fluid (GCF) levels of PGE2, LTB4 and periodontal health. METHODS: The periodontal condition of 24 subjects was evaluated on the basis of plaque index, gingival index, probing depth, and attachment level. GCF samples were collected from one or two site(s) of each sextant per subject and the volume was measured using Periotron 6000. Samples were then assayed for PGE2 and LTB4 using a competitive enzyme immunoassay. Mean PGE2 and LTB4 levels were determined for each subject and group means compared. RESULTS: Significant differences in the levels of PGE2 and LTB4 were found between patients with periodontitis, and non-periodontitis individuals (P < 0.001). The PGE2/LTB4 levels were positively correlated with the clinical parameters (P < 0.01) and reduced markedly after phase 1 of the periodontal treatment (P < 0.01). The total amount and concentration (ng ml-1) of LTB4 was positively correlated with the gingival index (P < 0.01). CONCLUSIONS: These results indicate that the levels of PGE2 correlated with the severity of the periodontal status, and the levels of LTB4 correlated with gingival inflammation. Thus, our data suggest that the total amounts of PGE2/LTB4 may be good indicators for periodontal inflammation.

Adult↗

PubMed1998

APACHE II score: a useful tool for risk assessment and an aid to decision-making in emergency operation for bleeding gastric ulcer.

BACKGROUND: Operating for bleeding gastric ulcer remains controversial. Gastric resection bears a higher surgical risk while limited operation may result in more postoperative hemorrhage. There has been little discussion of effective risk assessment of patients. The aim of this study is to define surgical risk by using the APACHE II scoring system, and to determine optimal management. STUDY DESIGN: Records from October 1990 to December 1996 were retrospectively reviewed for patients (n=101) with bleeding gastric ulcer who had undergone emergency operation after failed endoscopic therapy. Mortality rates were examined according to different APACHE II scores, and the surgical risk was defined. From January 1997 to December 1997, 35 consecutive patients were enrolled for prospective study. Partial gastric resection (PGR) was performed for patients with huge ulcers (>2 cm) and for low-risk patients with ulcers at the antrum or angularis, while limited operation (oversewing or excision of bleeding ulcer) was reserved for others. The results were compared with the retrospective study. RESULTS: In the retrospective study, the mortality rates for the group with a score < 15 and > or = 15 were 5% (3 of 63) and 58% (22 of 38), respectively (p < 0.05). In the group with a score < 15, PGR was performed on 27 patients, and one died. For those patients with a score > or = 15, PGR carried a lower mortality than limited operation, although this was not statistically significant (47% vs 65%). Limited operation resulted in an overall rate of 22% postoperative hemorrhage and 12% reoperation rate, in which all patients with a score > or = 15 died. In the prospective study, the mortality rates in those scoring <15 and > or = 15 were 6% and 50%, respectively. This is not significantly different than the retrospective study. However, the rate of postoperative hemorrhage was diminished (5%). CONCLUSIONS: APACHE II score is a useful tool for assessing risk in patients with bleeding gastric ulcer. The mortality is minimal in those with a score <15, and PGR can be performed with low risk. Although high-risk patients have dreadful outcomes, limited operation cannot improve them if postoperative hemorrhage occurs. Decision making in emergency operation for such patients should be based on the ulcer conditions and the patient's hemodynamic status.

APACHE↗

PubMed1998

Effect of different sources of dietary fibre on growth performance, intestinal morphology and caecal carbohydrases of domestic geese.

1. The aim of this study was to examine the effects of dietary fibre sources on growth and on the development of the gastro-intestinal tract in growing geese. 2. Six-week-old female White Roman geese were divided at random into 6 groups with 6 dietary treatments. Diets were isoenergetic and isonitrogenous and contained alfalfa meal, barley bran, rice hulls, cellulose, pectin or lignin as the major dietary source of fibre. 3. Food intake was significantly higher in the barley bran group than in the other groups. Both daily weight gain and food conversion of the pectin and alfalfa meal groups were lower than those of the other groups. 4. In the 9-week-old geese, the relative weight and the length of the small intestine did not significantly differ among treatment groups. However, the relative weight was significantly lightest and the caecal length was significantly shortest (P < 0.05) in the pectin group. 5. Activities of amylase and cellulose hydrolases of the caecal contents were also highest in the pectin group. 6. From SEM micrographs, no morphological damage of the villi was observable in the different intestinal segments of the geese in any of the treatments.

Amylases↗

PubMed1998

Gingival crevicular fluid lactoferrin levels in adult periodontitis patients.

The present study was designed to determine in a cross-sectional study whether there was any relationship between the levels of lactoferrin in gingival crevicular fluid and clinical periodontal parameters. Crevicular fluid was collected from individual sites using standardized filter paper strips (clinically healthy sites, N = 23; periodontitis sites, n = 66) and evaluated for lactoferrin by enzyme-linked immunosorbent assay. The data showed that: (1) the total amounts of lactoferrin were 0.003-0.021 ng (30 second sample) (average 0.009 +/- 0.005 ng) in a clinically healthy periodontium group and 0.016-3.847 ng (30 second sample) (average 0.575 +/- 0.069 ng) in adult periodontitis patients (statistically significantly higher in adult periodontitis patients); and (2) the total amounts of lactoferrin were significantly correlated with clinical parameters, especially a strong positive correlation with gingival crevicular fluid volume (r = 0.85, p < 0.01) and with probing depth (r = 0.71, p < 0.01). These results indicated that quantification of lactoferrin in gingival crevicular fluid may be a more sensitive indicator of periodontal pathology than traditional clinical indices.

Adult↗

PubMed1998

Effectiveness of postinoculation (R)-9-(2-phosphonylmethoxypropyl) adenine treatment for prevention of persistent simian immunodeficiency virus SIVmne infection depends critically on timing of initiation and duration of treatment.

(R)-9-(2-Phosphonylmethoxypropyl)adenine (PMPA), an acyclic nucleoside phosphonate analog, is one of a new class of potent antiretroviral agents. Previously, we showed that PMPA treatment for 28 days prevented establishment of persistent simian immunodeficiency virus (SIV) infection in macaques even when therapy was initiated 24 h after intravenous virus inoculation. In the present study, we tested regimens involving different intervals between intravenous inoculation with SIV and initiation of PMPA treatment, as well as different durations of treatment, for the ability to prevent establishment of persistent infection. Twenty-four cynomolgus macaques (Macaca fascicularis) were studied for 46 weeks after inoculation with SIV. All mock-treated control macaques showed evidence of productive infection within 2 weeks postinoculation (p.i.). All macaques that were treated with PMPA for 28 days beginning 24 h p.i. showed no evidence of viral replication following discontinuation of PMPA treatment. However, extending the time to initiation of treatment from 24 to 48 or 72 h p.i. or decreasing the duration of treatment reduced effectiveness in preventing establishment of persistent infection. Only half of the macaques treated for 10 days, and none of those treated for 3 days, were completely protected when treatment was initiated at 24 h. Despite the reduced efficacy of delayed and shortened treatment, all PMPA-treated macaques that were not protected showed delays in the onset of cell-associated and plasma viremia and antibody responses compared with mock controls. These results clearly show that both the time between virus exposure and initiation of PMPA treatment as well as the duration of treatment are crucial factors for prevention of acute SIV infection in the macaque model.

Adenine↗

PubMed1998

Thoracic neurilemomas: an analysis of computed tomography findings in 36 patients.

On computed tomography (CT), neurilemomas have generically been described as well-defined, round masses with heterogeneous contrast enhancement. The CT scans of 38 surgically proven thoracic neurilemomas in 36 patients were reviewed to characterize further the CT features of this tumor, with an emphasis on different enhancement patterns. Unenhanced CT was available in 32 patients; 10 tumors appeared isodense, and 22 tumors appeared slightly hypodense compared with chest wall muscle. Except for an intraosseous neurilemoma of the T8 vertebral body, which mimicked bone metastasis, the tumors could be categorized into five different patterns on CT after contrast enhancement. Twenty tumors (54.1%) revealed diffuse, but amorphous and inhomogeneous enhancement. Seventeen (45.9%) tumors appeared as masses with multiple hypodense or cystic areas. Of these 17, the pattern was somewhat radial enhancement (n = 6, 16.2%), peripheral enhancement with a large central hypodense area (n = 5, 13.5%), homogeneous hypodensity (n = 5, 13.5%), and central enhancement with peripheral hypodensity (n = l, 2.7%). Appreciation of various CT manifestations is important in the diagnosis of this tumor.

Adult↗

PubMed1998

A review of ocular emergencies in a Taiwanese medical center.

BACKGROUND: Ocular injury is one of the most common problems in the Emergency Department (ED), but a general survey of ocular injuries has rarely been reported in the literature. This article reviews cases of ocular injury collected in the ED of a medical center over a 12-month period. METHODS: A retrospective analysis was done on 1,314 consecutive patients who presented with eye complaints to the ED of the Veterans General Hospital-Taipei between November 1993 and October 1994. Common ocular diagnoses and their associated variables were assessed separately. RESULTS: Ocular injuries occurred in a male to female ratio of about 1.9:1 with a peak age in the third decade. Diagnoses were grouped as trauma (43.8%) and non-trauma (56.2%). Corneal abrasion was the most common trauma reported. The main circumstances of eye trauma were play (50.0%) in children (< 15 years), work (37.1%) in the age group of 16 to 59 years and domestic activity (45.8%) in patients over 60 years of age. Blunt objects and contusions (hits or falls) caused nearly 50% of all ocular injury cases. Most of the non-traumatic cases were due to acute conjunctivitis (19.1%), followed by contact lens (CL)-related disorders (11.4%). Three cases of CL-induced corneal ulcer resulted in permanent visual morbidity. There was a trend toward an increase in acute conjunctivitis in the summer, corneal ulcer in the spring and acute glaucoma in the winter. CONCLUSIONS: Young males were found to run a higher risk of ocular accidents, especially at work. Penetrating injuries with or without a retained intraocular foreign body were the leading cause of poor visual outcomes and often occurred in patients without protective eyeglasses. With the widespread use of CLs, many potentially serious complications were noted in the ED, which deserve attention.

Adolescent↗

PubMed1998

[Interleukin-6 production by human gingival fibroblasts following stimulation with Actinobacillus actinomycetemcomitans].

Actinobacillus actinomycetemcomitans(Aa), elaborating a multiplicity of virulence factor and tissue-damaging products, is considered an etiological agent in periodontal disease. Serotype b is the most frequently isolated serotype in localized juvenile periodontitis patients, suggesting a particularly high periodontopathic potential for serotype b strains. Interleukin-6(IL-6) plays an important role in the mediation of inflammatory and immune responses as well as in the osteoclastic bone resorption. However, there is little information regarding the effect of the different serotypes of Aa on IL-6 production by human gingival fibroblasts (HGF). Therefore, the purpose of this study was to compare the ability of the three serotypes (a, b, and c) of Aa sonicates to induce the production of IL-6 by HGF. In fibroblast cultures, confluent monolayers of HGF were incubated with sonic extracts of Aa-511 (serotype a), Aa-Y4 (serotype b), and Aa-652 (serotype c) at various concentrations for 48 h at 37 degrees C in 5% CO2 and air. At the end of the culture period, supernatants were collected and analysed for IL-6 content by using EIA and bioassay. In order to compare the effects of non-lipopolysaccharide (LPS) activation of Aa sonicates on IL-6 production by HGF, we added polymyxin B in cultures with Aa sonicates to bind LPS. The results were summarized as follows. (1) All three serotypes of Aa sonicates had similar dose-dependent stimulant effects on IL-6 production by HGF, and the biological activities of IL-6 correlated with their immunoreactivities. (2) The maximum releases of IL-6 by HGF were achieved at concentrations of 10 to 100 micrograms protein/mL of Aa sonicates, and the ability of Aa-Y4 to induce the release of IL-6 was higher than that of Aa-511 and Aa-652 at these concentrations. (3) Polymyxin B (50 micrograms/mL) effectively decreased the amounts of IL-6 produced by stimulation of the HGF with 10 micrograms protein/mL of Aa sonicates. However, the polymyxin B-treated Aa-Y4 sonicate showed a higher ability to induce the release of IL-6 than the other two strains. These results indicate that Aa-Y4 (serotype b) has a higher potency to induce HGF secretion of IL-6; thus contributing to a comparatively stronger efficacy to the destruction of periodontal tissue in periodontitis.

Adult↗

PubMed1998

[The influence of school staffs willingness and dental health education intervention on the oral hygiene status of the elementary school children].

The main purpose of this study was to understand the influence of school administrator's and teacher's participation in oral hygiene promotion, and dental health education intervention on the oral hygiene status of the elementary school children. Questionnaires designed to evaluate the school staff's willingness to emphasize and proceed the oral hygiene programs were answered by the school administrators (principals, deans of pupils' affair, chiefs of physical education and hygiene departments, and nurses) in 75 public elementary schools of the Kaohsiung City, Taiwan. Two of the most, and of the least cooperative schools were randomly selected. The fifth grade teachers of those four schools were asked to answer the questionnaires. Pupils of the two classes whose teachers who had the greatest and the least willingness to participate were selected for further investigation. Pupils were asked to answer questionnaires, receive oral examinations and tooth-brushing instructions every other two weeks for a total of two times. The results were as follows: 1. Before active oral hygiene instruction, there is no significant difference in plaque scores among groups. However, DMFT scores are influenced by school administrators. 2. The oral hygiene education intervention actually significantly improved the school children's plaque scores. 3. The cooperation of school administrators and teachers has a positive influence on keeping (forming) school children's good oral hygiene habits. Furthermore, the influence from school administrators is more than that from teachers. 4. School children's knowledge of oral hygiene is influenced by school' administrators and teachers while teachers' attitude of oral hygiene is influenced by school administrators.

Child↗

PubMed1998

A new classification of molar furcation involvement based on the root trunk and horizontal and vertical bone loss.

This study presents a new classification of molar furcation involvement based on the root trunk and horizontal and vertical attachments, and relates them to guidelines in diagnosis, prognosis, and treatment of molar furcation involvements. The type of root trunk were classified on the basis of the ratio of vertical dimension of root trunk to root length as types A, B, and C. Based on the results of this study, the authors conclude that consideration of the root trunk type as well as the horizontal and vertical attachment loss in the classification of molar furcation involvements may facilitate prognosis, diagnosis, and treatment planning.

Alveolar Bone Loss↗

PubMed1998

The role of CD8+ cells and CD11a in the rejection-reaction of the allogeneic microskin grafting.

By using histological tissue sections and immunohistochemical stains, the rejection-reaction of the allogeneic microskin grafting of rabbit-skin wounds was studied. The results revealed that the rejection started early in the days following transplantation. In the second week following transplantation, severe graft rejection with epithelial destruction was noted. In addition, an increase of CD8+ cells and expression of the adhesion molecule-CD11a-were also noticed and persisted throughout the days following transplantation. These findings suggest that the CD8+ cells and CD11a may play a major role in the rejection of allogeneic skin grafting.

Animals↗

PubMed1998

Bone regeneration in advanced periodontitis lesions after a single episode of root planing--case report with ten-years of follow-up.

This report describes a significant bone regeneration in a mandibular molar with advancing long-standing periodontal disease (defect extending to apex and into furcation) following a single episode of scaling and root planing. A 52-year-old female suffered from generalized moderate periodontitis for two years. An acute periodontal abscess with a 12 mm probing depth around the right mandibular first molar was noted. After incision and drainage, thorough scaling and root planing was performed under local anaesthesia. Three months later, radiographic examination showed complete bone regeneration with formation of a distinct lamina dura. It was concluded that favorable clinical and radiographic results could be obtained after a single episode of thorough subgingival root planing combined with excellent oral hygiene maintenance.

Bone Regeneration↗

PubMed1998

Astigmatic change following congenital ptosis surgery.

BACKGROUND: High astigmatism is frequently associated with congenital ptosis. Ptosis surgery itself may also induce astigmatic refractive change that will cause amblyopia in young children. The purpose of this study was to assess postoperative astigmatic change and the effect of different ptosis surgical procedures on astigmatism. METHODS: An analysis of 63 consecutive surgical cases of congenital ptosis was conducted. The preoperative incidences of anisometropia, amblyopia, strabismus and high astigmatism were evaluated. All patients underwent levator resection or received frontalis sling. The postoperative astigmatic change after the follow-up period of 12 months was assessed in 28 patients. It included a total of 40 ptotic eyelids from 12 bilateral and 16 unilateral cases of ptosis. The eyes on the contralateral side in unilateral cases served as the control group. RESULTS: In 63 cases of congenital ptosis, 30.2% (19/63) were associated with anisometropia and 39.7% (25/63) with amblyopia, and 11.1% (7/63) were combined with strabismus. Most cases of amblyopia were associated with high astigmatism (64%). The incidence of high astigmatism (> 2.5 diopters, D) in congenital ptosis was 25.3%. Of 40 ptotic eyelids included for the study of postoperative astigmatism change, 15% showed an increase of more than 0.5 D, whereas 27.5% showed a decrease of more than 0.5 D, and no significant change was observed in 57.5%. An average decrease of 0.18 D in astigmatism was observed, while no statistical difference was found between the study group and the control group for astigmatic change. Moreover, both the levator resection and frontalis sling groups showed a decrease in average cylinder, and again, demonstrated no statistically significant difference in astigmatic change. CONCLUSIONS: A high incidence of amblyopia was associated with astigmatism in congenital ptosis. Postoperative astigmatic study also revealed some change in astigmatic power, but no new cases of amblyopia developed after ptosis surgery. Patients with congenital ptosis should have cycloplegic refraction as soon as possible, and long-term postoperative refraction check-up is also recommended.

Adolescent↗

PubMed1997

Localization of protein kinase C alpha and zeta during the decidualization in pseudopregnant rats.

Our previous data showed that at least five PKC isoforms (alpha, delta, zeta, lambda and tau) were present in the decidualization. In this study, we then localized the PKC alpha and zeta by immunohistochemistry in the decidualized uterine tissues. The decidualized uterine tissues were induced by trauma-stimulation and fixed in formalin. The immunofluorescence were photographed by confocal microscope. The data revealed that the fluorescence of PKC alpha was present in the deciduomata and myometrium. In the deciduomata, PKC alpha was mainly located in the surrounding nuclear. This phenomenon of localization was especially performed on day 2 and 3 of the decidualization, just on the time of higher frequence of cell mitosis. Since the myometrium with hypertrophy did not display the phenomenon of perinuclear localization, these suggested that the expression and localization of PKC alpha may be associated with the cell proliferation. On the other hand, the PKC zeta was also present and distributed broadly in the deciduomata and myometrium. This expression was increased and similar to the previous Western blot studies. Thus, the data confirmed that the various expression and localization of PKC isoforms may be correlated with the development of deciduomata.

Animals↗