Biomedical subjects

H Lin

Publications and source records attributed to H Lin.

At least 235 records · Page 13Linked to original sources

PubMed1998

Palladium(II) complexes with N,N'-dialkyl-1,10-phenanthroline-2,9-dimathanamine: synthesis, characterization and cytotoxic activity.

Five new tetradentate ligands and their corresponding palladium complexes, [Pd(L)]Cl2 (L = N,N'-dimethyl-1,10-phenanthroline-2,9-dimathanamine, N,N'-diethyl-1,10-phenanthroline-2,9-dimathanamine, N,N'-dipropyl-1,10-phenanthroline-2,9-dimathanamine, N,N'-ditert-butyl-1,10-phenanthroline-2,9-dimathanamine, N,N'-dicyclohexyl-1,10-phenanthroline-2,9-dimathanamine) have been synthesized. The ligands and their complexes have been characterized by elemental analysis, IR, and 1H NMR. The complexes have been assayed for antitumor activity in vitro against the mouse leukemia L1210 and the mouse liver carcinoma Bel7402 cell lines. The results showed that the activities of these complexes are significantly dependent on the nature of the alkyl groups on the coordinated amine moieties, and three of these palladium complexes showed lower ID50 values against the two cell lines than cisplatin.

Animals↗

PubMed1998

The self-renewing mechanism of stem cells in the germline.

Germline stem cells (GSCs) are a self-renewing population of germ cells that serve as the source of gametes in diverse organisms. Current research suggests that the self-renewing division of GSCs is controlled both by somatic signaling and by intracellular mechanisms such as differential gene expression, asymmetric cytoskeletal organization, and the cell cycle machinery. These findings provide a framework for the further study of GSCs and stem cell renewal in general.

Animals↗

PubMed1998

Pretreatment for cellulose hydrolysis by carbon dioxide explosion

Cellulosic materials were treated with supercritical carbon dioxide to increase the reactivity of cellulose, thereby to enhance the rate and the extent of cellulose hydrolysis. In this pretreatment process, the cellulosic materials such as Avicel, recycled paper mix, sugarcane bagasse and the repulping waste of recycled paper are placed in a reactor under pressurized carbon dioxide at 35 degreesC for a controlled time period. Upon an explosive release of the carbon dioxide pressure, the disruption of the cellulosic structure increases the accessible surface area of the cellulosic substrate to enzymatic hydrolysis. Results indicate that supercritical carbon dioxide is effective for pretreatment of cellulose. An increase in pressure facilitates the faster penetration of carbon dioxide molecules into the crystalline structures, thus more glucose is produced from cellulosic materials after the explosion as compared to those without the pretreatment. This explosion pretreatment enhances the rate of cellulosic material hydrolysis as well as increases glucose yield by as much as 50%. Results from the simultaneous saccharification and fermentation tests also show the increase in the available carbon source from the cellulosic materials for fermentation to produce ethanol. As an alternative method, this supercritical carbon dioxide explosion has a possibility to reduce expense compared with ammonia explosion, and since it is operated at the low temperature, it will not cause degradation of sugars such as those treated with steam explosion due to the high-temperature involved.

Journal Article↗

PubMed1998

The role of the hedgehog/patched signaling pathway in epithelial stem cell proliferation: from fly to human.

The hedgehog-patched (hh-ptc) intercellular signaling pathway has recently been shown to control the proliferation of epithelial stem cells in both Drosophila and vertebrates. Mutant and ectopic expression analyses in Drosophila suggest that the HH protein diffuses from the signaling cells to promote the proliferation of nearby ovarian somatic stem cells by antagonizing the suppression of its receptor PTC towards the CI transcription factor in the stem cells. Consequently, the transcription of CI-dependent genes leads to stem cell proliferation. This regulatory pathway appears to function also in vertebrates, where defects in ptc cause basal cell carcinoma, tumors of epidermal stem cell origin. Basal cell carcinoma can also be induced by ectopic expression of Sonic hedgehog (shh) or Gli1, the vertebrate homolog of ci. These studies suggest the conservation of the hh signaling pathway in controlling epithelial stem cell divisions among different organisms.

Animals↗

PubMed1998

Inhibition of gastric emptying and intestinal transit by amphetamine through a mechanism involving an increased secretion of CCK in male rats.

1. The effect of amphetamine on gastrointestinal (GI) transit and the plasma levels of cholecystokinin (CCK) were studied in male rats. 2. Gastric emptying was inhibited both acutely and chronically by the administration of amphetamine. GI transit was decreased by the acute administration of amphetamine but not affected by the chronic administration of amphetamine. 3. Plasma CCK levels were increased dose-dependently by amphetamine. 4. Proglumide, a CCK receptor antagonist, prevented amphetamine-induced inhibition of gastric emptying and the decrease in GI transit in male rats. 5. The selective CCK(A) receptor antagonist, lorglumide, dose-dependently attenuated the amphetamine-induced inhibition of gastric emptying in male rats. In contrast, the selective CCK(B) receptor antagonist, PD 135,158, did not reverse the effect of amphetamine on gastric emptying. 6. Both lorglumide and PD 135,158 reversed the inhibitory effect of amphetamine on GI transit in male rats. 7. These results suggest that amphetamine-induced inhibition of gastric emptying and intestinal transit is due in part to a mechanism associated with the hypersecretion of endogenous CCK.

Amphetamines↗

PubMed1998

Inhibitory effect of digoxin on testosterone secretion through mechanisms involving decreases of cyclic AMP production and cytochrome P450scc activity in rat testicular interstitial cells.

1. In vivo and in vitro experiments were performed to examine inhibitory effects of digoxin on testosterone secretion and to determine possible underlying mechanisms. 2. A single intravenous injection of digoxin (1 microg kg(-1)) decreased the basal and human chorionic gonadotropin (hCG)-stimulated plasma testosterone concentrations in adult male rats. 3. Digoxin (10(-7) - 10(-4) M) decreased the basal and hCG-stimulated release of testosterone from rat testicular interstitial cells in vitro. 4. Digoxin (10(-7) - 10(-4) M) also diminished the basal and hCG-stimulated production of cyclic 3':5'-adenosine monophosphate (AMP) and attenuated the stimulatory effects of forskolin and 8-Br-cyclic AMP on testosterone production by rat testicular interstitial cells. 5. Digoxin (10(-4) M) inhibited cytochrome P450 side chain cleavage enzyme (cytochrome P450sec) activity (conversion of 25-hydroxy cholesterol to pregnenolone) in the testicular interstitial cells but did not influence the activity of other steroidogenic enzymes. 6. These results suggest that digoxin inhibits the production of testosterone in rat testicular interstitial cells, at least in part, via attenuation of the activities of adenylyl cyclase and cytochrome P450sec.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1998

Review and evaluation of MRI nonuniformity corrections for brain tumor response measurements.

Current MRI nonuniformity correction techniques are reviewed and investigated. Many approaches are used to remedy this artifact, but it is not clear which method is the most appropriate in a given situation, as the applications have been with different MRI coils and different clinical applications. In this work four widely used nonuniformity correction techniques are investigated in order to assess the effect on tumor response measurements (change in tumor volume over time): a phantom correction method, an image smoothing technique, homomorphic filtering, and surface fitting approach. Six brain tumor cases with baseline and follow-up MRIs after treatment with varying degrees of difficulty of segmentation were analyzed without and with each of the nonuniformity corrections. Different methods give significantly different correction images, indicating that rf nonuniformity correction is not yet well understood. No improvement in tumor segmentation or in tumor growth/shrinkage assessment was achieved using any of the evaluated corrections.

Biophysical Phenomena↗

PubMed1998

Treatment of carcinoma of the hard palate with gamma knife radiosurgery.

The Gamma Knife radiosurgical treatment of two patients suffering from carcinomas of the hard palate is reported. A 67-year-old woman was treated with partial resection of an adenocarcinoma of the hard palate two years previously. Computerized tomographic imaging showed the tumor had grown (T4N1M0). The second patient, a 58-year-old woman, had a cauliflower-like tumor of the hard palate (T2N0M0). Pathological diagnosis obtained by needle biopsy was squamous cell carcinoma. These two patients underwent radiosurgical treatment with the Gamma Knife. A surface dose of 20 Gy was administered at the 35% isodose curve. These two patients were followed up for 18 and 15 months, respectively. Encouraging results were obtained. Further research is needed in order to validate this new treatment of carcinomas of the hard palate.

Adenocarcinoma↗

PubMed1998

Antioxidative activities of several marine polysaccharides evaluated in a phosphatidylcholine-liposomal suspension and organic solvents.

The antioxidative activities of several water-soluble marine polysaccharides, alginate (ALG), alginate sulfate (SALG), propylene glucolalginate sodium sulfate (PSS), propylene glucol mannuronate sulfate (PGMS), the oligosaccharide of chitosan (OLC), N,O-carboxymethyl chitosan (NOCC) and hydroxypropylated chitosan (HPC), were examined in a phosphatidylcholine (PC)-liposomal suspension containing the water-soluble radical emitter, 2,2'-azobis (2-amidinopropane) dihydrochloride. In the suspensions containing OLC and SALG, the initial rates of PC-OOH accumulation were 2.78 x 10(-8) MS-1 and 2.88 x 10(-8) MS-1, respectively, while all the polysaccharides tested showed antioxidative activity. Liposoluble marine polysaccharides, hexanoyl chitin (HCH) and an N-benzoylhexanoyl chitosan (NBHC) solution, also retarded the hydroperoxide accumulation of methyl linoleate by effectively trapping peroxide radicals in organic solvents when the radical chain reaction had been initiated by 2,2'-azobis (2,4-dimethylvaleronitrile). The kinetic data presented indicate that the alginate and chitin derivatives can be expected to play a role in the antioxidative mechanism of biological systems.

Alginates↗

PubMed1998

Survival advantages and complications of adjuvant therapy in early-stage cervical cancer with pelvic node metastasis.

BACKGROUND: Patients with early-stage cervical cancer who have pelvic node metastasis usually need adjuvant therapy after surgery for improvement of the length of survival. We attempted to determine the survival advantages and complications associated with different adjuvant therapeutic modalities. MATERIALS AND METHODS: Eighty-seven patients with clinical stage Ib and IIa cervical cancer were treated with radical hysterectomy from July 1986 through December 1994 were reviewed retrospectively. All had had lymph node metastasis. The patients were divided into three groups according to the different adjuvant therapeutic approaches utilized: radiation (group I, n = 43), chemotherapy (group II, n = 23), and chemoirradiation (group III, n = 21). RESULTS: There was no significant difference among these three groups in the 5-year relapse-free survival rate (group I: 63%, group II: 62%, group III: 51%, p = 0.785). The recurrence rates among these three groups were found to be similar (group I: 32.6%, group II: 39.1%, group III: 47.6%, p = 0.331). However, most of the recurrence in patients who had received pelvic radiation was at a distant site (group I: 79%, group III: 80%) as compared to the patients who had received chemotherapy only (group II: 33%), and the differences were significant (p = 0.020). The rates of complications, such as severe leukopenia, lymphedema with cellulitis, proctosigmoiditis and ileus, were found to be lower in the chemotherapeutic group. CONCLUSION: Although we failed to demonstrate the survival advantages of different adjuvant therapeutic approaches, we still favor chemotherapy as an adjuvant basis because it is the least toxic of the regimens.

Adult↗

PubMed1998

[Ultrasonic measurements of fetal thigh soft tissue thickness in the estimation of fetal weight].

OBJECTIVE: To study ultrasonic measurement of fetal thigh soft tissue thickness in the estimation of fetal weight. METHODS: Fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL) and fetal thigh soft tissue thickness (FTSTT) were measured by ultrasonography and analyzed with neonatal birth weight in 178 cases. RESULTS: There was significant correlation between FTSTT and neonatal birth weight (r = 0.8601), and it is better to estimate fetal weight with FTSTT than with the other parameters. The sensitivity and specificity for detection of macrosomia was 91% and 94%, respectively. The FTSTT was positively correlated with gestational age (r = 0.7070). CONCLUSION: The ultrasonic measurement of FTSTT is a simple, accurate and valuable index in estimation of fetal weight.

Adult↗

PubMed1998

[Association of apoB levels and nutrition of coronary heart disease patients].

Blood lipids and apo B levels were measured on 101 Coronary Heart Disease patients and 100 controls. The results showed that the apo B levels of patients were higher than that of controls. The average values were (877 +/- 129) mg/L and (800 +/- 95) mg/L respectively. It was found that there was close association among body mass index(BMI), ratio of waist circumference to hip circumference(WHR) and apo B levels. Besides, the results showed that dietary habit of "eating fat meat" might result in the increase of apo B concentration while the VC intake was negatively associated with serum apo B levels.

Adult↗

PubMed1998

[Levels of endothelin and beta-human chorionic gonadotropin and their relationship in patients with pregnancy induced hypertention].

OBJECTIVE: To measure levels of endothelin (ET) and beta-human chorionic gonodotropin (beta-hCG) and analyse the correlation between them in patients with pregnancy induced hypertension (PIH), as well as to investigate their role in the pathogenesis of PIH. METHODS: 32 patients with PIH were matched with 17 normal term singleton pregnant women. ET and beta-hCG levels of above patients and 14 nonpregnant health reproductive age women were determined by radioimmunoassay. RESULTS: ET and beta-hCG levels were significantly higher in patients with PIH (30.35 +/- 14.52 ng/L and 7.35 +/- 4.86 nmol/L) than that of two control groups (P < 0.05), especially in middle and severe PIH (P < 0.05), but no significant different in mild PIH (P > 0.05), compared with normal pregnant group (20.79 +/- 7.08 ng/L and 4.13 +/- 1.91 nmol/L) and nonpregnant group (19.78 +/- 6.66 ng/L and 0 nmol/L). There was no significant difference of plasma ET levels between normal pregnant and nonpregnant women (P > 0.05). beta-hCG in nonpregnant woman hadn't been determined. We did not find any association between the levels of ET and beta-hCG in normal pregnancy (r = +0.2216, P > 0.05), but significant positive correlation in the patients with PIH (r = +0.5418, P < 0.01). CONCLUSION: The increased levels of ET and beta-hCG, as well as their positive correlation, suggested that the dysfunction of the placental cells may be associated with the endothelial cell damage in PIH patients.

Adult↗

PubMed1998

[The detection of CD56 in T-cell lymphoma and its relationship with Epstein-Barr virus].

OBJECTIVE: To investigate the expression of CD56 and the relationship between CD56 positive expression and EBV infection in T-cell lymphoma (TCL) in Guangdong province. METHODS: Immunohistochemistry was used to detect CD56 and in situ hybridization was used to detect EBER in 46 cases of TCL. RESULTS: (1) 17.4% (8/46) TCL were CD56 positive. According to the site of origin, the TCL originated from the nose, pharynx and oral cavity had the highest CD56 positive rate (5/17, 29.4%). Anyhow, according to the type pattern, the diffuse large cell lymphoma had the highest CD56 positive rate (6/16, 37.5%). (2) 52.2% (24/46) of the TCl were EBER positive. (3) 4/8 cases of the CD56 positive TCl expressed EBER. CONCLUSION: The findings suggest that the expression of CD56 in TCL was possibly related to original sites and TCL subtypes. EBV infection was not related to CD56 positive TCL in this study.

CD56 Antigen↗

PubMed1998

[Clinical study on qiangxinling liquid extract in treating congestive heart failure].

OBJECTIVE: To find the safe and effective treatment and drugs for congestive heart failure (CHF). METHODS: Ninety CHF patients whose heart function belong to III-IV grade were randomly divided into 3 groups: Group A was treated with Qiangxinling liquid extract (QXLLE); Group B with QXLLE plus small dose of digoxin and Group C with digoxin alone. RESULTS: The total effective rate on heart function of Group A was 86.7%, Group B 93.3% and Group C 83.3%, the effect of Group B was better than that of the other two groups (P < 0.05, P < 0.01). The digoxin withdrawing and reducing rate in Group B was higher than that in Group C (86.7% vs 50.0%, P < 0.05). The left ventricular systolic function, including stroke volume, cardiac output, ejection fraction of the 3 groups were improved after treatment, among them the effect of Group B was the best (P < 0.01). Moreover, improvement in ventricular diastolic function was shown in Group A and B, including the maximum blood flow of the late and the early diastolic stage as well as the ratio of them (P < 0.05, P < 0.01). The plasma renin activity, angiotensin II and atrial natriuretic peptide of Group A and B were also lowered after treatment and were significantly different to those of the Group C (P < 0.01). CONCLUSIONS: QXLLE could improve the heart function, clinical symptoms and neuro-endocrinal indexes of CHF patients and reduce the side effects of digoxin.

Adult↗

PubMed1998

[Study on the in vitro and in vivo thrombolytic efficacy of bispecific antifibrin-antiurokinase monoclonal antibodies].

OBJECTIVE: To evaluate the thrombolytic efficacy of bispecfic antifibrin-antiurokinase monoclonal antibodies. METHODS: Murine hybrid hybridomas secreting bispecific monoclonal antibodies (bsMcAbs) were prepared by fusing a mutant hybridomas secreting antifibrin McAbs with spleen cells of murine immunized with urokinase. The binding power of bsMcAbs with fibrin or urokinase was determined by ELISA method. The in vitro thrombolytic efficacy was measured by the dissolving rate of 131I-plasma clot. The in vivo thrombolytic efficacy was measured by using the rabbit jugular vein thrombus model. RESULTS: 8 strains of bsMcAbs have been obtained. ELISA experiments showed that bsMcAbs have very strong binding power with fibrin or urokinase. The bsMcAbs bound with urokinase increased the in vitro thrombolytic efficacy of urokinase by 15.5%. The in vivo thrombolytic efficacy of bsMcAbs bound with urokinase was 1.6-2.1 times as high as urokinase. CONCLUSIONS: Monoclonal antibody-directed thrombolytic agents have advantages of high specificity and strong local thrombolytic efficacy. It is well worth going on further study.

Animals↗

PubMed1998

[Multiple subpial transection in surgical treatment of intractable epilepsy].

OBJECTIVE: To increase the effect of epilepsy surgery, we use multiple subpial transection (MST) clinically on the basis of experimental study. METHOD: We analyzed the seizure type and course of 116 intractable epilepsy patients treated with MST and surgical technique were modified. RESULT: 100 patients were followed up for 1 to 5 years. Complete control of seizure was obtained in 62 patients (62%), significant reduction (over 75%) in 20 (20%), reduction (over 50%) in 12 (12%), and no change in 6 (6%). The total effective rate was 94%, and the significant effective rate was 82%. No functional defect was found in any patients. CONCLUSION: MST is a effective in surgical treatment of intractable epilepsy and can replace conventional methods. Combined bilateral frontal lobe MST and anterior callosotomy is a good way to treat intractable generalized epilepsy.

Adolescent↗

PubMed1998

[Clinical diagnostic standard of mediopatellar plica syndrome].

OBJECTIVE: To increase the level of clinical diagnosis of mediopatellar plica syndrome. METHOD: We reviewed the preoperative clinical symptoms of 67 knee joints that were proved to have pathologic mediopatellar plica by arthroscopy. RESULT: Mediopatellar plica syndrome had the following clinical symptoms: painful knee and mediopatellar tenderness in all patients; tender bands in 56.7% patients; positive test of flexion or extension with internal femoral condyle pressed in 62.7% patients; positive Mcmarry's sign in 31.3% patients. CONCLUSION: The clinical diagnostic standard of mediopatellar plica syndrome is that the first above-mentioned clinical symptom plus one of other three symptoms could suggest the diagnosis, while the first clinical symptom plus two or three of other three symptoms could define the diagnosis.

Adult↗