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Biomedical subjects

L Yan

Publications and source records attributed to L Yan.

At least 199 records · Page 11Linked to original sources
PubMed1997

Effect of dietary supplementation of selenite on pulmonary metastasis of melanoma cells in mice.

The purpose of the present study was to determine the effect of dietary supplementation of selenite on experimental pulmonary metastasis of B16BL6 murine melanoma cells in C57BL/6 mice by means of an intravenous injection model. Three groups of mice were fed a basal AIN-93G diet containing 0.1 ppm selenium (control group) or the basal diet supplemented with 2 or 4 ppm selenium as selenite (experimental groups). Mice were fed the diet for two weeks before and after the intravenous injection of 0.75 x 10(5) viable tumor cells. At necropsy the number of tumors that developed in the lungs and their cross-sectional area were determined, and tumor volume was calculated. In the control group, 12 of the 15 mice had > or = 1 lung tumors. In contrast, only 4 of the 15 mice in each of the selenite-supplemented groups had > or = 11 tumors. The incidence of metastasis in mice fed the control and the 2- and 4-ppm selenium diets was 93%, 73%, and 53%, respectively. The median number of lung tumors was 53, 1, and 1 in mice fed the basal and the 2- and 4-ppm selenium diets, respectively. Tumor cross-sectional area and tumor volume were significantly decreased in selenite-supplemented groups. These results demonstrate that dietary supplementation of selenite reduced pulmonary metastasis of B16BL6 melanoma cells in C57BL/6 mice and also inhibited the growth of the metastatic tumors that developed in the lungs. It is concluded that selenite may be a useful adjuvant to prevent metastatic diseases in cancer patients.

Animals↗
PubMed1997

Effect of dietary supplementation of soybeans on experimental metastasis of melanoma cells in mice.

The purpose of the present study was to determine the effect of dietary supplementation of soybean protein isolate (SPI) on experimental metastasis of B16BL6 murine melanoma cells in C57BL/6 mice. Four groups of mice were fed a basal AIN-93G diet or the basal diet supplemented with 10%, 15%, or 20% SPI for two weeks before and after the intravenous injection of 0.75 x 10(5) cells. At necropsy the number of tumors that developed in the lungs and their cross-sectional area were determined, and tumor volume was calculated. In the control group, 12 of the 15 mice had > or = 11 lung tumors. In contrast, only 3 or 4 of the 15 mice fed the SPI diets had > or = 11 tumors. The incidence of metastasis was 93%, 60%, 53%, and 53%, and the median number of lung tumors was 53, 2, 2, and 1 in mice fed the basal, 10%, 15%, and 20% SPI diets, respectively. Tumor cross-sectional area and tumor volume of SPI groups were significantly decreased compared with the controls. These results demonstrate that dietary supplementation of SPI reduced pulmonary metastasis of B16BL6 cells in mice and inhibited the growth of tumors that developed in the lungs. It is concluded that soybeans may be a useful adjuvant for preventing metastatic diseases in cancer patients.

Animals↗
PubMed1997

Helicobacter rodentium sp. nov., a urease-negative Helicobacter species isolated from laboratory mice.

A spiral-shaped bacterium with bipolar, single, nonsheathed flagella was isolated from the intestines of laboratory mice. The organism grew at 37 and 42 degrees C under microaerobic and anaerobic conditions, did not hydrolyze urea, was weakly positive for catalase and oxidase, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and was resistant to cephalothin and nalidixic acid. This is the first urease-negative, murine Helicobacter spp. isolated from intestines. Also, Helicobacter pullorum and this bacterium are unique among the genus Helicobacter in having nonsheathed flagella. The new bacterium appears to be part of the normal intestinal flora; although its pathogenic potential is unknown, this organism was also isolated from scid mice with diarrhea that were co-infected with Helicobacter bilis. On the basis of 16S rRNA gene sequence analysis data and biochemical and phenotypic criteria, the new organism is classified as a novel helicobacter, for which we propose the name Helicobacter rodentium. The type strain is MIT 95-1707 (= ATCC 700285).

Animals↗
PubMed1997

Promotion of ulcerative duodenitis in young ferrets by oral immunization with Helicobacter mustelae and muramyl dipeptide.

BACKGROUND: The purpose of this study was to determine whether oral immunization of ferret kits with a whole-cell sonicate of Helicobacter mustelae lysate (Hml) and the adjuvant muramyl dipeptide (MDP) would reduce the incidence of natural colonization with H. mustelae and the extent of Helicobacter-associated gastritis by enhancing the host mucosal immune response. MATERIALS AND METHODS: Between the ages of 4 and 11 weeks, 44 ferret kits were gavaged with Hml and various doses of MDP. The extent of gastritis and duodenitis and the immune response to H. mustelae were evaluated. RESULTS: All kits became colonized naturally with H. mustelae and the majority developed mild to severe gastritis and duodenitis. Kits that received Hml with MDP developed significantly greater inflammation of the gastric antrum and duodenum, as compared to kits vaccinated with Hml alone. Vaccination with Hml and 50 micrograms of MDP was associated with severe lesions in the proximal duodenum characterized by accumulation of mononuclear inflammatory cells, mucosal erosion, and ulceration. Although serum antibody specific for H. mustelae in 4-week-old kits was approximately 50% of adult levels, a finding attributable to passively acquired maternal antibody, both systemic and mucosal antibody levels became depressed over time despite oral vaccination. The humoral immune response was sufficiently low to prevent detection of any significant dose effect of MDP on antibody levels among experimental groups. CONCLUSIONS: Oral vaccination of young ferrets with Hml and 50 micrograms MDP increased the risk of Helicobacter-associated mucosal ulceration in the proximal duodenum, which was associated with low humoral (but significant cell-mediated) immune responses to H. mustelae. In retrospect, the frequency of vaccination may have suppressed the systemic humoral immune response, thereby promoting mucosal damage by H. mustelae. The 50-microgram dose of MDP enhanced the cell-mediated immune response, which indirectly contributed to development of severe lesions. The increased frequency of mucosal damage associated with this vaccination regimen enhances the value of the ferret model for studying duodenal ulceration secondary to Helicobacter infection.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1997

Vitamin D status does not influence the breast-milk calcium concentration of lactating mothers accustomed to a low calcium intake.

Plasma 25-hydroxy-vitamin D and breast-milk calcium concentration were measured at 3 months of lactation in 60 Gambian mothers accustomed to a low calcium diet, of whom 30 were consuming a calcium supplement and 30 were receiving a placebo, and in 48 British mothers. The plasma 25-hydroxy-vitamin D concentration of the Gambian women was not affected by either calcium supplementation (supplemented, 64.4 +/- 2.5 nmol l(-1); placebo, 64.9 +/- 3.5 nmol l(-1); mean +/- SE) or season. The British average was lower (53.9 +/- 3.0 nmol l(-1), p = 0.004), owing to marked seasonal effects. The breast-milk calcium concentration was lower in The Gambia (supplemented, 5.38 +/- 0.13 mmol l(-1); placebo, 5.10 +/- 0.13 mmol l(-1); British, 6.93 +/- 0.15 mmol l(-1), p < 0.0001). There was no relationship between plasma 25-hydroxy-vitamin D and breast-milk calcium concentration in any group. There was no trend towards lower breast-milk calcium concentration in women with vitamin D status towards the bottom of the normal range or in British women during the winter. This study provides no support for the hypothesis that breast-milk calcium concentration is influenced by vitamin D status or that lactating women with a low calcium intake are at particular risk of vitamin D deficiency.

Adolescent↗
PubMed1997

Infection of the ferret stomach by isogenic flagellar mutant strains of Helicobacter mustelae.

Helicobacter mustelae, like Helicobacter pylori, possesses two flagellin proteins, FlaA and FlaB. Isogenic mutant strains of H. mustelae have been constructed by disruption of the flaA or flaB gene with a kanamycin resistance cassette or by introduction of both a kanamycin and a chloramphenicol resistance gene to produce a double mutant. To determine whether one or both flagellin proteins are necessary for colonization and persistence of infection with H. mustelae, 19 ferrets, specific pathogen free for H. mustelae, were given either the HMF1 flaA::km (weakly motile), ATCC 43772 flaB::km (moderately motile), or HMF1 flaA::cat flaB::km (non-motile) mutant strain, the wild-type parent strains, or sterile broth. Gastric tissue samples were obtained during sequential gastric biopsies beginning at 3 weeks postinoculation and ending at necropsy at 3 months postinoculation. H. mustelae infection status was determined by culture, histology, and serology. The wild-type parent strains of H. mustelae infected all ferrets at all time points. The double-mutant strain was unable to colonize; the flaA and flaB single-mutant strains were able to initially colonize at a low level and establish persistent infection with increasing numbers of organisms over time. The severity of gastritis produced by infection with these strains of H. mustelae correlated with the number of organisms present in the gastric mucosa. Flagellar motility is an important virulence factor for colonization and pathogenesis in the H. mustelae ferret model.

Animals↗
PubMed1997

[Indications for operation in patients with acute necrotizing pancreatitis].

The opportunity of and indications for operation in patients with acute necrotizing pancreatitis (ANP) are still controversial. One hundred and ninty surgical cases of ANP were analyzed. Early operation was performed in 2 weeks from onset, and late operation after 2 weeks. In the early operation, the pancreatic sporadic focal necrosis was found in most cases (75.6%), and main postoperative complications were disturbance of blood circulation and organic function injury of pancreas. The postoperative mortality rate was 28.2%. In the late operation, extensive fusional pancreatic necrosis was found in most cases (53.7), and most complications were located in the organs mear the pancreas. The authors conclude that late operation is better for the treatment of ANP. The indications of early and late operation were discussed.

Adolescent↗
PubMed1997

[Surgical treatment for advanced gallbladder cancer].

To rise the resection rate and survival rate for advanced gallbladder cancer (GBC), we operated on forty cases of advanced GBC. 34 cases had obstractive jundice, and 8 palpable abdominal mass. Externded radical cholecystectomy was performed in 11 cases of advanced GBC in which the tumor invaded the surrounding organs or tissues but without distantce metastasis. Follow-up showed that the survival period was between 8 and 32 months (average 18.8 months), 1 and 2 years survival rates were 54.4% and 27.3%. Palliative operations were performed in other 29 advanced GBC cases of distant metastasis. All of the cases died within one year. We suggest that extended radical cholecystectomy is effective for advanced GBC.

Adenocarcinoma↗
PubMed1997

[The effect of heterogeneous scleral transplantation on hypotony after filtration surgery of glaucoma with mitomycin C].

OBJECTIVE: The study was designed to observe the effect of heterogeneous scleral transplantation in treatment of hypotony after filtration surgery of glaucoma with mitomycin C. METHOD: 7 patients (8 eyes) with hypotony after filtration surgery of glaucoma with mitomycin C were treated by heterogeneous scleral transplantation. RESULTS: The post-operative follow-up periods ranged from 3 to 19 months (mean 7.75 +/- 5.37 months). Postoperatively, the visual acuity was increased in 5 eyes, and the intraocular pressure was increased to normal level in all eight eyes. CONCLUSION: Heterogeneous scleral transplantation has therapeutic effects in the treatment of hypotonic eyes after filtration surgery of glaucoma.

Adolescent↗
PubMed1997

[Influence of idiotypic network regulation on renal transplant].

Pretransplant sera from 68 patients were tested for antiidiotypic antibodies (Ab2) and anti-antiidiotypic antibodies (Ab3) by lyphocytotoxicity inhibitory and potentiating assay. In the first six nomths, 6% of the patients in the Ab2 group had had a rejection episode compared with 21% of the patients in the no antibody (P < 0.01), whereas patients in the Ab3 group had significant rejection episodes (67%) compared with no antibody group (P < 0.01). These results suggest that Ab2 can introduce recipients tolerating the graft in some degree and patients with Ab3 are of high risk of graft rejection.

Adult↗
PubMed1997

[The vascular basis of pedicled adrenal transposition and its usage in the treatment of Cushing's disease].

To treat Cushing's disease, we studied the length and exterior diameter of the inferior phrenic and superior adrenal artery and vein, and the reflow of the adrenal vein. The length and exterior diameter of those blood vessels were divided and measured by veiner calipor. Six patients with Cushing's disease were treated by pedicled adrenal transposition to the musculus of the back. The right inferior phrenic artery was 75-110 mm from the exterior edge of the vena cava to the distant branch of the superior adrenal artery, while the left inferior phrenic artery was 70-90 mm from the left edge of the aorta to the distant branch of the superior adrenal artery, both of which have veins to accompany them. The superior adrenal artery came from the inferior phrenic artery relatively common and was divided into six branches. The exterior diameter of the distal superior adrenal artery was 1.5-2.5 mm and could be freed for 40-80 mm. Lateral veins could complete the adrenal blood drainage after the left central adrenal vein was ligated. The transpositioned blood vessel pedicle consisted of the distant inferior phrenic artery and vein, the distant branches of the superior adrenal artery and vein. The patient who had received the transposition treatment had neither hypocortisolism nor recurrence after 4 to 35 months. The length of the inferior phrenic, superior adrenal gland vessels could content the remained adrenal gland to reach their transposition bed when freed. The pedicled adrenal transposition to the musculi is an ideal method in the treatment of Cushing's disease.

Adrenal Glands↗
PubMed1997

[Effect of haemorrheological changes on acute pancreatitis].

This study sought to determine the effect of the haemorrheological changes on the pathological damage to pancreas in acute pancreatitis. 96 Wistar rats, four months old, were allocated into three groups: group I (n = 32) received surgery for pancreatic duct obstruction (PDO) with secretion stimulation; group II (n = 32) for PDO with high molecular dextran (DX110) injection intravenously, and group III (n = 32) for PDO with secretion stimulation and DX110 injection intravenously. Ten other rats were used as controls (group IV) for laparotomy alone. The results showed that PDO with hypersecretion could induced edematous pancreastitis and PDO with DX110 injection induced only very lightly oedema in the pancreas which was similar to the result of PDO alone, although the haemorrheological changes were obvious in these rats. PDO with hypersecretion and DX110 injection induced acute necrotic pancreatitis, and the pathological lesion in the pancrease which changed gradually from edematous to necrotic could be observed. This result suggests that haemorrheological change may not be a causative factor of the acute necrotic pancreatitis, but it probably could exacerbate the damage to pancreas in acute pancreatitis and play an important role in the transformation from edematous to necrotic pancreatitis.

Animals↗
PubMed1997

[A medical ultrasonic image compression method based on vector quantization].

In this paper we presented a new compression intension based on VQ with an in tension to provide an efficient approach to compressing medical ultrasonic images and thus make the establishment of a medical multimedia database possible. The major advantages of this coding scheme are: high compression rate, low distortion, higher speed of encoding procedure as compared with ordinary VQ. These benefits are mainly due to the unique design of the codebook and enhanced table look-up techniques. In addition, a comparison of this scheme with JPEG compression method (at high compression rate) was presented.

Electronic Data Processing↗
PubMed1997

[The side effect and complication of intraarterial phosphorus-32 glass microspheres for patients with advanced hepatoma].

The phosphorus-32 glass microspheres(32P-GMS) is a new radioembolizer for cancer therapy. From March 1994 to April 1995, 24 patients with unresectable hepatocellular carcinoma and 3 patients with cavernous hemangioma received internal radiation treatment of 32P-GMS. The clinical results demonstrated that hepatic arterial instillation of 32P-GMS appeared to be safe and effective for hepatocellular carcinoma. There was no significant bone marrow or renal toxicity or liver to pulmonary bypass. A transient change of liver function and fever occurred in almost all patients. Significant liver toxicity and gastrointestinal tract reaction were seen when radiation dose > 50 Gy or microspheres > 3 g, and then various postoperative complications occurred.

Adult↗
PubMed1996

Effects of Monovalent, Exchangeable Cations and Electrolytes on the Infrared Vibrations of Smectite Layers and Interlayer Water

Infrared spectroscopy was used to investigate how nuSi-O, the frequency of Si-O stretching, in layers of Li- and Na-montmorillonite and nu2, the frequency of H-O-H bending, in the interlayer water were affected by increasing the concentration, C, of LiCl and NaCl, respectively. Oriented gels of Li- and Na-montmorillonite equilibrated with solutions having various values of C were obtained by using a miniature pressure membrane apparatus. One part of each gel was used for the gravimetric determination of mw/mc, the water content. The other part was transferred to an FTIR spectrometer where the spectrum of the gel was measured by attenuated total reflectance. Thus, the dependence of both nuSi-O and nu2 on mw/mc was determined in the same samples. The results showed that increasing C had little or no effect on the relation between nuSi-O and mw/mc, or on the relation between nu2 and mw/mc. The vibrational coupling of Si-O stretching in the montmorillonite layers and H-O-H bending in the interlayer water was demonstrated. It was essentially independent of the species of exchangeable cation and C. Thus neither the species of exchangeable cation nor C had any specific effect on the structure of the clay layers or the structure of the interlayer water.

Journal Article↗
PubMed1996

Parallel synthesis and screening of a solid phase carbohydrate library.

A solid phase carbohydrate library was synthesized and screened against Bauhinia purpurea lectin. The library, which contains approximately 1300 di- and trisaccharides, was synthesized with chemical encoding on TentaGel resin so that each bead contained a single carbohydrate. Two ligands that bind more tightly to the lectin than Gal-beta-1,3-GalNAc (the known ligand) have been identified. The strategy outlined can be used to identify carbohydrate-based ligands for any receptor; however, because the derivatized beads mimic the polyvalent presentation of cell surface carbohydrates, the screen may prove especially valuable for discovering new compounds that bind to proteins participating in cell adhesion.

Acylation↗