Biomedical subjects

Z Chen

Publications and source records attributed to Z Chen.

At least 487 records · Page 27Linked to original sources

PubMed2000

[Anatomy in relation to posterior maxillary osteotomy].

OBJECTIVE: The most common site of haemorrhage in maxillary osteotomies is the posterior maxilla. Better understanding of the anatomy of this region would minimize possible vascular complications. The aim of this study is to investigate the anatomy of posterior maxilla and establish safety guidelines for Le Fort I osteotomy. METHOD: Thirty dry human skulls were selected for direct measurement and computerized image analysis. RESULTS: Synosteosis of the pterygomaxillary junction was noted in 10% of the samples. The height of the pterygomaxillary junction was 13.15 mm. The height from the inferior point of the pterygomaxillary junction to the inferior point of the maxillary tuberosity was 5.25 mm. The height from the superior point of the pterygomaxillary junction to the inferior point of the maxillary tuberrosity was 18.05 mm. The average distance from the piriform rim to the descending palatine canal was 35.25 mm. The width of the pterygoid process was 12.34 mm. The average length from the zygo-alveolar ridge to the pterygomaxillary junction was 25.47 mm. The average length from anterior nasal spine to the posterior nasal spine was 46.27 mm, and the angle between the descending palatine canal and the palate plane was 58 degrees 47'. CONCLUSIONS: The study is to provide further understanding of the posterior maxillary anatomy in relation to the bone-cut design of Le fort I osteotomy and to create clinical safety guidelines in order to avoid damaging the descending palatine vessels.

Adult↗

PubMed2000

[The experimental study on acute and chronic expansion of the facial nerve].

OBJECTIVE: To investigate and compare the feasibility of acute and chronic expansion of the facial nerve so as to provide referable parameters for clinical practice. METHODS: Buccal branches of rabbits' facial nerve were expanded with the expander designed and manufactured by us. The nerve was elongated 10 mm per 10 min in the acute group, and 1.5-2.0 mm per day in the chronic group. The nerve injury due to expansion, the nerve retraction after expansion and the limit of elongation were investigated. When the expansion was completed, 1.0 cm segments of the nerve in both acute and chronic groups were removed and epineurium neurorrhaphy was performed. The same length of the nerve in the control group was resected and replanted. Electromyogram(EMG) and nerve conductive velocity (NCV) were measured at the 15th week of expansion to assess the function of the repaired nerve. The pathological changes were also observed. RESULTS: 1. The nerve retracted obviously during the first hour after expansion. The difference were significant between the acute group (37.6 +/- 4.5)% and the chronic group (8.2 +/- 2.1)%. 2. Excluding the retraction portion, the limit elongation was (18.7 +/- 2.4)% and (31.8 +/- 2.4)% in acute and chronic group respectively. 3. To get the same elongation within the limit, nerve injury was more severe pathologically in the acute group than in the chronic one at the end of the expansion while EMG and NCV were not different considerably. 4. Within the limit elongation, the same result of neurorrhaphy was gained in the acute, chronic and the control groups. CONCLUSIONS: Acute expansion of the facial nerve is feasible. When the defect is less than 20% of the nerve, acute expansion is indicated. When it is over 20% but less than 30%, a chronic method should be taken into consideration. The same outcome of repair should be gained if the expansion is within the limit elongation.

Animals↗

PubMed2000

[CO2 release from typical Stipa grandis grassland soil].

Determinations on the soil respiration in a typical Stipa grandis grassland of Inner Mongolica by the method of static chamber/alkaline absorbing show that there existed great spatial and temporal variances of soil respiration, and the factors controlling these variances were different. The seasonal variance of soil respiration had a close relationship with the aboveground biomass of S. grandis and the status of soil moisture. The total amount of annual CO2 release in 1995, 1997 and 1998 was estimated as 180, 45.8 and 225 gC.m-2.yr-1, respectively. Overgrazing greatly decreased the biomass of the community, and also, decreased the CO2 release from the soil. The possibility of establishing a dynamic model of soil respiration in grassland with precipitation as a driven factor was discussed.

Biomass↗

PubMed2000

[Behavior response of four Leis axyridis varieties to volatiles from tea and Toxoptera aurantii].

The behavior response of the adults of four Leis axyridis varieties to kairomone from Taxoptera aurantii was determined by Y-shape olfaction instrument. The results showed that when supplied with two-two-combinations of Taxoptera aurantii, Brevicoryne brassicae and Lipaphis erysimi, tea aphids plus aphid-damaged vs. normal shoots, and aphid-damaged vs. normal shoots, Leis axyridis had a preference for tea aphids, tea aphids plus aphid-damaged tea shoots, or aphid-damaged tea shoots. There existed a Logistic curve relationship(P < 0.01) between odor source tendency rate of Leis axyridis and odor source quality, when 8-9 kinds of odor gradients including tea aphids plus aphid-damaged tea shoots, aphid-damaged tea shoots and tea aphids were used as odor sources. The tendency rates of Leis axyridis ab. bimaculata, Leis axyridis ab. conspicua and Leis axyridis var. novemdecimpunctata showed single left-tilting peak curves to the aphid number(P < 0.01). Ether and n-hexane ringes of Toxoptera aurantii body surface also showed an attraction to all varieties. Leis axyridis var. spectabilis was the most sensitive variety.

Animals↗

PubMed2000

Effect of all-trans retinoic acid on growth of xenograft tumor and its metastasis in nude mice.

OBJECTIVE: To study the effect of all-trans retinoic acid on growth of xenograft tumor and its metastasis in nude mice. METHODS: Human gastric cancer BGC-823 and MKN-45 cells were inoculated into spleen subcapsule of nude mice, respectively. The nude mice were subsequently administered with all-trans retinoic acid every other day. Food consuming and body weight of nude mice were measured weekly. Six weeks later, the nude mice were killed. Xenograft tumors in spleen and metastatic tumors in liver were pathologically examined. Microvessel density in the tumors was detected immunohistochemically, and serum carcinoembryonic antigen was measured by radioimmunoassay. RESULTS: After the nude mice were fed with all-trans retinoic acid, the growth of splenic tumor and its liver metastasis were inhibited and the metastatic rates decreased by 50% (BGC-823) and 33.3% (MKN-45), respectively. The microvessel density in splenic and hepatic tumors reduced by 28.58% and 35.47% (BGC-823), 19.45% and 14.52% (MKN-45), respectively. The concentration of carcinoembryonic antigen decreased by 50.24% (BGC-823) and 48.10% (MKN-45). CONCLUSION: All-trans retinoic acid may effectively inhibit the growth of xenograft tumor in spleen and its metastasis to liver in nude mice, which can be corroborated by the decrease of carcinoembryonic antigen and microvessel density.

Animals↗

PubMed2000

Expression of the human multidrug resistance gene mdr1 in leukemic cells and its application in studying P-glycoprotein antagonists.

OBJECTIVE: To investigate the retrovirus-mediated transfer and expression of multidrug resistance gene (mdr1) in hematopoietic cells and to develop a model for studying the possible reversal of the MDR-mediated phenotype. METHODS: A retroviral vector HaMDR expressing the human mdr1 gene was packaged by PA317 cells with a titer of up to 8.5 x 10(5) CFU/ml. K562 leukemia cells were infected with MDR retrovirus, and transfectant K562/MDR cells were generated. The integration and expression of the exogenous mdr1 gene in K562/MDR cells were determined by polymerase chain reaction and flow cytometry. The reversal ability of P-glycoprotein (P-gp) antagonists was analyzed by in vitro drug sensitivity, accumulation and efflux of rhodamine 123 (Rh123) in this model. RESULTS: Transduction with amphotropic MDR retrovirus resulted in integration and expression of the mdr1 gene in the resistant cells, where an aberrant splicing transcript of the mdr1 gene was found. The K562/MDR cells displayed a classic MDR phenotype with a 41-78 fold resistance to vincristine and colchicine in comparison with parental K562 cells. The drug sensitivity of K562/MDR cells to vincristine can be completely restored by cyclosporin A (CsA, 2 mg/L) and Cremophor EL (CRE 132 mg/L), either individually or in combination (P < 0.05). CsA (3 mg/L) can block the efflux pump function of P-gp shown by the significantly increased accumulation and efflux reduction of Rh123 in K562/MDR cells. CONCLUSIONS: Retroviral vector HaMDR allows transfection with high-level expression of the mdr1 gene in human myeloid progenitor cells K562. The transfected K562/MDR provides a simple, sensitive model for developing antagonists of P-gp and studying their mechanism of action.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Hemostatic abnormalities associated with acute promyelocytic leukemia and corrective effects of all-trans-retinoic acid or arsenic trioxide treatment.

OBJECTIVE: To study in vivo effect of all-trans-retinoic acid (ATRA) or arsenic trioxide (As2O3) on the expression of tissue factor (TF) and the hemostatic disorders, a series of parameters were measured in bone marrow blasts and plasma from acute promyelocytic leukemia (APL) patients. METHODS: The plasma variables were measured by ELISA or chromogenic study. The TF transcription was assessed using reverse transcription-polymerase chain reaction technique (RT-PCR). RESULTS: The blast cell procoagulant activity (PCA), TF antigen of APL cell lysates, as well as the transcription of APL TF mRNA elevated at diagnosis, were reduced after ATRA or As2O3 therapy. The plasma level of platelet alpha-granular membrane protein-140, soluble fibrinomonomer complex, thrombomodulin, tissue plasminogen activator and D-dimer significantly increased, fibrinogen, antigen level of protein C, plasminogen, alpha 2-plasminogen inhibitor and plasminogen activator inhibitor decreased at diagnosis, were restored to normal after complete remission but protein C activity and protein S remained elevated in ATRA group. CONCLUSIONS: There existed activation of platelets and consumption of anticoagulants as well as activation of coagulation and fibrinolytic system before treatment. Both ATRA and As2O3 therapy down-regulated the expression of TF mRNA, decreased the PCA and TF level in APL cells, inhibited coagulation activation, secondary hyperfibrinolysis and recorrected other hemostatic abnormalities, thus greatly improved the bleeding symptom in early stage of the treatment.

Adolescent↗

PubMed2000

Arg485Lys polymorphism of factor V increases the risk of coronary artery disease in a Chinese population.

OBJECTIVE: To explore the relationship between genetic variation in coagulation factor V and the occurrence of coronary arterial disease (CAD). METHODS: Unrelated 86 patients with CAD and 102 healthy controls were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to detect variations in the entire twenty-five exons of the factor V gene. RESULTS: Polymorphisms in exon 4 [642 G-->T (Ser156)], exon 10 [1628 G-->A (Arg485Lys)], exon 13 [4070 A-->G (His1299Arg)] and exon 16 [5380 G-->A (Val1736Met)] were documented. The study also identified a novel polymorphism in exon 2 (327 A-->G) which did not result in amino acid residue substitution. The Leiden mutation (Arg506Gln) was not detected in any of our 188 subjects. Among the 5 polymorphisms, the allele frequency of 1628 G-->A was significantly different between CAD patients and controls (0.69 vs 0.81, chi 2 = 6.908, P < 0.01). This is the first report of this finding in a Chinese population. CONCLUSION: 1628 G-->A polymorphism is associated with CAD and it may be a risk factor for CAD morbidity in the Chinese population.

Aged↗

PubMed2000

Mechanism of inhibition on activator protein-1 activity by all-trans retinoic acid in gastric cancer cells.

OBJECTIVE: To determine the mechanism of all-trans retinoic acid (ATRA) on growth inhibition in human gastric cancer cells. METHODS: Gastric cancer cell lines: MGC80-3, BGC-823, SGC-7901 and MKN-45. CAT assay, Northern blot, Western blot, gene transfection and MTT assay. RESULTS: ATRA can inhibit the activator protein-1 (AP-1) activity in ATRA-sensitive cell lines, but not in ATRA-resistant cell line, and the anti-AP-1 activity of ATRA is mediated by its receptor, retinoic acid receptor alpha (RAR alpha). ATRA can also inhibit the expression of cJun and cFos. One of the mechanisms for ATRA to inhibit the growth of gastric cancer cells may be through its inhibitory effect on the AP-1 activity and its influence on up-regulation of RAR alpha expression. The inhibition of cJun and cFos expressions by ATRA may also contribute to the anti-AP-1 activity. CONCLUSIONS: ATRA inhibits the growth of gastric cancer cells through the regulation of AP-1 activity. This action is mediated by RAR alpha.

Antineoplastic Agents↗

PubMed2000

Relationship between gene expression of nitric oxide synthase and androgens in rat corpus cavernosum.

OBJECTIVE: To clarify the dependence of neural nitric oxide synthase mRNA (nNOSmRNA) and endothelial nitric oxide synthase mRNA (eNOSmRNA) on androgens (testosterone [T] and dihydrotestosterone [DHT]). METHODS: 160 male Sprague Dawley (SD) rats were divided into Groups A (56 rats, 5 weeks old), B (50 rats, 10 weeks old) and C (54 rats, 58 weeks old). Groups A, B and C were all subdivided respectively into five Subgroups. Subgroup 1: intact controls; Subgroup 2: castrated; Subgroup 3: castrated with testosterone undecanoate 25 mg/kg.mon-1, intramuscular injection, Subgroup 4: castrated with testosterone undecanoate 50 mg/kg.mon-1, intramuscular injection and Subgroup 5: treated with finasteride 4.5 mg/kg.day-1, orally. Four and ten weeks after treatments described above, one half of the rats were killed. Serum samples were taken for measurements of T, free testosterone (FT) and DHT by radioimmunoassay. Penile samples were treated with liquid nitrogen and then stored at -80 degrees C. nNOSmRNA and eNOSmRNA were detected by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) and Dot blot. RESULTS: There was no significant difference between Subgroup 1 and Subgroup 2 or Subgroup 5 in all Groups A, B and C. The expression of penile eNOSmRNA of Group A was significantly increased (4 weeks model) (P < 0.05) or increased (10 weeks model) (P > 0.05) in Subgroup 2 or 5 compared with those in Subgroup 1. There was no significant difference between Subgroup 1 and Subgroup 2 or Subgroup 5 of Group B in 4 weeks model (P > 0.05). There was an elevation when animals were castrated or treated with finasteride in the 10 weeks model. The expression of penile eNOSmRNA of Group C was significantly increased (10 weeks model) (P < 0.05) or increased (4 weeks model) in Subgroup 2 compared with those in Subgroup 1. The production of eNOSmRNA in Subgroup 5 was also increased (including 4- and 10-week models). When T was supplied for castration, the penile eNOSmRNA was decreased to some extent; the greater the dose of T given, the lower penile eNOSmRNA was observed. CONCLUSIONS: The expression of eNOSmRNA in SD rat penile tissue increases while T or DHT diminishes. Sometimes androgens modulate penile eNOSmRNA in opposite directions. There is no correlation between the expression of nNOSmRNA and androgens (including T and DHT). Androgens give rise to penile erection probably not via the NOS pathway.

Androgens↗

PubMed2000

Changes in systemic and splanchnic hemodynamics after orthotopic liver transplantation in cirrhotic rats.

OBJECTIVE: To investigate early changes in systemic and splanchnic hemodynamics after orthotopic liver transplantation (OLT) in normal and cirrhotic rats. METHODS: Male Sprague-Dawley rats were divided into 4 groups: normal controls (NL, n = 10), intrahepatic portal hypertension (IHPH, n = 10) induced by injection of CCl4, normal rats with OLT (NL-OLT, n = 9) and IHPH rats with OLT (IHPH-OLT, n = 16). IHPH-OLT rats were divided into 2 subgroups: 3 days (Group A, n = 9) and 7 days (Group B, n = 7) after OLT. OLT was performed in rats using cuffs for the anastomosis of the suprahepatic inferior vena cava, infrahepatic vena cava and portal vein. Two weeks after production of IHPH rats, 7 days after NL-OLT rats, 3 days and 7 days after IHPH-OLT rats, radioactive microspheres were used in a hemodynamic study. RESULTS: There were no significant differences in hemodynamic changes between NL-OLT and NL rats, except mean arterial blood pressure (MAP). The characteristics of systemic and splanchnic hyperdynamic circulatory state, including increased cardiac output and splanchnic blood flow, decreased mean arterial blood pressure, total peripheral vascular resistance and splanchnic vascular resistance were observed in IHPH, IHPH-OLT A, and IHPH-OLT B rats. The magnitude of hyperhemodynamics was in the order of IHPH > IHPH-OLT A > IHPH-OLT B rats. Moreover, the derangement of splanchnic hyperhemodynamics was more significant than that of systemic hyperthermodynamics. CONCLUSIONS: The present study demonstrates that the persistence of early systemic and splanchnic hyperkinetic circulation after OLT may be the consequence of factors which maintain hyperhemodynamics in liver cirrhosis, where portal hypertension is not completely eliminated. Hyperhemodynamics is not induced by OLT per se.

Animals↗

PubMed2000

[Mechanisms of drug resistance of primary renal cell carcinomas and their clinical significance].

OBJECTIVE: By multifactorial analysis, to study the mechanisms of drug resistance of primary renal cell carcinomas (RCC). METHODS: Seventy cases of paraffin-embedded RCC tissue sections were examined for the expression of P-gp, GST-pi and Topo II by immunohistochemical staining. RESULTS: There was 65.7% of RCC with expressed P-gp. Its Expression was stronger in late than in early stage of RCC. GST-pi was expressed in 41.1% RCC, but the magnitude of expression did not correlate with differentiation, type and stage of RCC. All the RCC examined had Topo II expression. Its expression level was lower than that of cancer of the intestine and lung. Among the 70 cases of RCC, 31.4% of them expressed at least one of the 3 drug-resistance parameters. Co-expression of two drug-resistance parameters was observed in 42.8% of the cases that of 3 drug-resistauce parameters in 22.9% of the cases. CONCLUSION: Drug resistance is of common occurrence in RCC. To achieve better therapeutic efficacy, appropriate chemotherapeutic agents should be given to patients with low expression of P-gp and GST-pi but high expression of Topo II.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

[Establishment of facial nerve elongation model by string-type loading].

OBJECTIVE: To study the repairing method of facial nerve defect using nerve elongation, and the biomechanical properties of peripheral nerves. METHODS: A novel device for peripheral nerve elongation was designed and manufactured. With the device, facial nerves of rabbits were expanded acutely and chronically by string-type loading. The facial nerves were studied with histological and electrophysiological examinations before and after elongation. RESULTS: There were no considerable necrosis, degeneration, and infection in the facial nerves after elongation. The experimental animals took food normally and their body temperature were stable. Histological examinations showed dispersing Sunderland degree III injury and occasionally broken capillary blood vessels in the acute group, thicker nerve and fibroblasts hyperplasia between nerve bundles in the chronic group. The electromyogram(EMG) of buccal muscle and nerve conductive velocity(NCV) showed the maximal range was (18.7 +/- 2.4)% in the acute group, and (30.8 +/- 2.4)% in the chronic group. CONCLUSION: It suggests that the novel nerve elongation method is feasible, and it can be used to study the nerve elongation basically and clinically.

Animals↗

PubMed2000

[Clinical and pathological analysis of 114 patients with postoperative wound infections by M. abscessus].

OBJECTIVE: To evaluate the pathological findings of postoperative wound infections by M. abscessus. METHODS: Proven sources of infections in 114 patients with postoperative wound infections were contaminated instrument disinfection liquid. According to the wound exudates cultivation and bacteriologic identification, the pathogen of postoperative infections was proved M. abscessus. Pathological features of postoperative wound infections were analyzed retrospectively. RESULTS: The postoperative wound infections in 114 cases involved cutaneous and subcutaneous tissue 95(83.3%), deep muscular tissue 21(18.4%), local lymph nodes 13(11.4%) and visceral organ, peritoneum and mesentery 3(2.6%). The main pathological appearances were granulomatous lesions and nonspecific chronic pyogenic inflammations. The granulomatous lesions include pyogenic tuberculosis-like granuloma, atypical tuberculosis-like granuloma and tuberculosis-like granuloma. The three types of granuloma could be seen in the same case and the percentage of three types was 75.4%, 28.1%, 59.6% respectively. 38 cases (33.3%) were showed red mycobacterium at acid-fast stain. CONCLUSIONS: The pathological appearances of most postoperative wound infections by M. abscessus were more or less different from those of tuberculosis. Awareness of the pathologic features of the postoperative wound M. abscessus infections will facilitate the diagnosis so that appropriate therapy may be initiated before the disease is far advanced and prevent infection dissemination.

Adolescent↗

PubMed2000

[Mechanism of retinoic acid receptor alpha-mediated growth inhibition of gastric cancer cells by all-trans retinoic acid].

OBJECTIVE: To study the mechanism of retinoic acid receptor alpha(RAR alpha) in mediating growth inhibition of gastric cancer cells by all-trans retinoic acid(ATRA). METHODS: Expression of RAR alpha was detected by Northern blot. After anti-sense RAR alpha or sense RAR alpha had been transfected into gastric cancer cell lines BGC-823 and MKN-45 respectively, the inhibitory effect of ATRA on cell growth in stable clones was analyzed using MTT assay and colony forming assay in soft agar. The transcriptional activation of retinoic acid response element (RARE) was measured by CAT assay. RESULTS: ATRA could induce expression of RAR alpha in BGC-823 cells, but not in MKN-45 cells. In stable clones, ATRA could inhibit growth of MKN-45 cells transfected with RAR alpha gene, but could not inhibit that of BGC-823 cells transfected with antisense RAR alpha. Transient transfection and CAT assay showed higher beta-RAR response element (beta RARE) transcriptional activation induced by ATRA in MKN-45 cells transfected with RAR alpha compared to parental MKN-45 cells, while lower beta RARE transcriptional activation was seen in BGC cells transfected with antisense RAR alpha gene compared to parental BGC-823 cells. CONCLUSION: Sufficient level of RAR alpha is required for growth inhibition of gastric cancer cells by ATRA.

Antineoplastic Agents↗

PubMed2000

[Evaluation of ten-year results of cancer prevention and treatment in Changle City with high incidence of gastric cancer].

OBJECTIVE: To evaluate the results of cancer prevention and treatment over a 10-year period (1988-1997) in Changle City with high incidence of gastric cancer. METHODS: The results were analysed with sick rate random test, trend test, GM and Kaplan-Meier method with SAS statistical software. RESULTS: During the ten years, the sick rate of malignant tumors in male residents initially increased but then decreased. Gastric cancer had a tendency to decline. There was no obvious change for females. By short-term prediction, the sick rate of malignant tumors and gastric cancer would decrease, and that of liver cancer remain steady. The life expectancy of male residents increased 4.2 years and that of female residents increased 1.8 years from 1988 to 1997 if cancer death was ignored, but the increase was not significant if only deaths from gastric and liver cancers were excluded. The 5-year survival rate of gastric cancer and liver cancer increased 8.8% and 29.3% from 1988 to 1990, respectively. The cumulative risk rate of gastric cancer in males was 3 times as high as that of females, and that of liver cancer in males was 2.5 times as high as that of females. CONCLUSION: Sustained measures of cancer prevention and treatment woult anticipate further improvement of health status of Changle's residents in the years to come.

Aged↗

PubMed2000

[Titer and avidity of serum antibody to Porphyromonas gingivalis before and after periodontal therapy].

OBJECTIVE: To observe the changes of titer and avidity of serum antibody to Porphyromonas gingivalis (Pg) before and one month after periodontal therapy, and to observe the correlation of titer and avidity of anti-Pg IgG with clinical indices. METHODS: ELISA and DEA-ELISA were used to determine the titer and avidity of serum IgG antibody to Pg381 before and one month after periodontal treatment in 17 periodontitis patients and 6 healthy control subjects. RESULTS: The titers of anti-Pg IgG antibody were higher in periodontitis patients than in healthy control subjects (P < 0.001). All patients were seropositive (titers to Pg were higher than 2-fold above the median for control subjects). IgG antibody avidity to Pg in periodontitis patients were not found to be significantly lower than that in control group. The titers to Pg decreased significantly at one month after periodontal therapy, but antibody avidity didn't change. Serum anti-Pg antibody titers had a tendency of negative correlation with probing depth. The antibody titers were significant higher in periodontitis patients with < or = 5 mm mean probing depth than in patients with > 5 mm mean probing depth. CONCLUSIONS: It is suggested that the humoral immune response to Pg381 is protective and this protective effect mainly depends on the titer of antibody.

Antibodies, Bacterial↗

PubMed2000

[The effect of non-surgical periodontal and adjunctive minocycline-HCL treatments on collagenase activity].

OBJECTIVE: To evaluate the effect of scaling and root planing combined with local application of 2% minocycline hydrochoride ointment(Periocline) on the level of collagenase activity releasing from PMNs in GCF. METHODS: This was a randomized, single-blinded, split mouth design study. The target sites of 31 patients with moderate to severe periodontitis (PD > 5 mm) was randomized by left-side and right-side into one of the two groups (the test group and the control group). Subsequently each patient was scheduled for two appointments for the full-month supra-gingival scaling and oral hygiene instruction. At baseline all patients received subgingival scaling and root planing and were followed by 4-time applications of Periocline with one-week interval for totally four weeks in the test group. All patients were taken GCF for measuring collagenase by the method of Nakashima et al (1996) and were examined based on four parameters, including plaque index, pocket depth, attachment loss and bleeding on probing. RESULTS: Four weeks after root planing with 4-time applications of Periocline, all clinical parameters and active collagenase in GCF decreased significantly in the test groups[(593 +/- 112) mU/sample vs (311 +/- 98) mU/sample, P < 0.001]. On the other hand, simple root-planing therapy had limited effect on the active collagenase[(611 +/- 123) mU/sample vs (523 +/- 127) mU/sample], although all clinical parameters were also reduce significantly. Interestingly, seven weeks later, gingival inflammation and the active collagenase were reduced more significantly than those after four-week root planing in both groups[Test: (311 +/- 98) mU/sample vs (207 +/- 57) mU/sample; CONTROL: (523 +/- 127) mU/sample vs (345 +/- 117) mU/sample, P < 0.001]. At eleven week, gingival inflammation and the level of collagenase activity were rebounded in the control group[(467 +/- 108) mU/sample]. However, in the test group they were kept in lower level[(213 +/- 121) mU/sample]. The level of collagenase activity showed significantly positive correlation with GCF volumes and AL in two groups. CONCLUSION: These results indicate that local application of 2% minocycline hydrochoride ointment may effectively inhibit the level of active collagenase from PMNs and may inhibit connective tissue breakdown by inhibiting neutrophil collagenase.

Adult↗