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245 records · Page 14Linked to original sources
PubMed1990

[The antitumor activity of bovine serum albumin-mediated conjugate of hematoporphyrin derivative with antigastric cancer monoclonal antibody].

Hematoporphyrin derivative (HPD) was conjugated with a murine monoclonal antibody (3H11) against human gastric cancer through bovine serum albumin (BSA) as an intermediate. In this paper, the antitumor activity of indirect conjugate 3H11-BSA-HPD was demonstrated and compared with that of direct conjugate 3H11-HPD in vitro and in vivo. The molar ratios of the conjugates 3H11-BSA-HPD and 3H11-HPD were 1:200 and 1:37, respectively. The cytotoxicities of 3H11-BSA-HPD and 3H11-HPD plus exposure to light were shown to be similar, and much greater than those of free HPD at equivalent HPD concentration in vitro. When tumor-bearing nude mice were treated with the different conjugates or HPD plus exposure to light, all the six mice of the control group formed tumor within 13 days after inoculation of BGC 823 cells (2 x 10(5) cells/mouse), whereas five of the six mice treated with 3H11-BSA-HPD or 3H11-HPD were tumor free for the observation period of 34 days.

Animals↗
PubMed1990

Cyclic AMP inhibits fibronectin gene expression in a newly developed granulosa cell line by a mechanism that suppresses cAMP-responsive element-dependent transcriptional activation.

The main role of the ovarian granulosa cells is to nurse the oocyte and to produce estradiol and progesterone upon stimulation by gonadotropins. In fact, follicle-stimulating hormone (FSH) and luteinizing hormone control the expression of several genes during granulosa cell differentiation via cyclic AMP-dependent phosphorylations. Cyclic AMP stimulates transcription of genes that carry the cAMP-responsive element (CRE,5'TGACGTCA3') in their promoters. The fibronectin (FN) gene contains one CRE sequence at position -170. However, gonadotropins and cAMP inhibit FN gene expression in granulosa cells. To study the mechanism of the inhibition we developed a bovine granulosa cell line (BGC-1) that synthesizes estradiol in response to FSH and in which FSH and dibutyryl cAMP specifically decrease FN synthesis and its mRNA levels. The inhibitory effect (a) is not due to an alteration in FN mRNA stability, (b) requires upstream sequences other than CRE, located between positions -510 and -223, that are able to bind granulosa cell nuclear proteins, (c) is entirely dependent on the synthesis of intermediate proteins induced and or phosphorylated by cAMP, and (d) effectively suppresses the CRE-dependent transcriptional activation.

Animals↗
PubMed1989

[The specific photodynamic effect of monoclonal antibodies conjugated with hematoporphyrin derivative on gastric cancer in vitro and in vivo].

A murine monoclonal antibody (MoAb) BB4.3 raised against human gastric cancer cell line BGC823 was purified with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. The MoAb BB 4.3 was conjugated with hematoporphyrin derivative (HPD) by using carbodiimide. The conjugate HPD-BB4.3 retained both antibody activity and photochemical activity of HPD. In vitro the phototoxic effect of HPD-BB4.3 conjugate on target cells was about 15 times higher than that of free HPD. The target-selective photocytotoxicity of HPD-BB 4.3 was verified by the fact that this conjugate showed greater cytotoxicity than the corresponding normal mouse IgG (NIgG) conjugated with HPD, and that it showed less cytotoxicity to BB4.3 negative reaction cell line B-80 than to BGC 823; and moreover, its cytotoxicity to BGC823 cells could be blocked specifically by excess BB4.3 antibody. In an in vivo study, nude mice inoculated with 2 X 10(5) BGC823 cells were administered HPD-BB4.3, HPD, HPD-NIgG, HPD plus BB4.3 and PBS respectively; and were then exposed to light. Out of six animals treated with HPD-BB4.3 conjugate, four remained tumor-free for a long time. There was significant difference between HPD-BB 4.3 treated group and all control groups. The HPD-BB4.3 conjugate was also shown more than 40% inhibition of growth of established tumors in comparison with the control groups.

Animals↗
PubMed1989

[Experimental study of anti-tumor effect with conjugates of monoclonal antibodies and hematoporphyrin derivative].

Hematoporphyrin derivative (HPD) is a photosensitizer for use in photodynamic therapy (PDT). In this paper, HPD was conjugated with monoclonal antibodies 3G9 or 3H11 for use against gastric cancer in order to enhance the photosensitive effect and reduce side effect of PDT. The biological activities of the McAb conjugates were demonstrated. The killing effect on BGC-823 cells of 3G9-HPD or 3H11-HPD conjugates plus exposure to light showed 17 fold and 8.6 fold greater cytotoxicity, respectively than free HPD at an equivalent HPD concentration in vitro. When 3G9-HPD and 3H11-HPD were used in combination at 7:3, 5:5 and 3:7 proportion, the cytotoxicity was increased 12.9, 11.8 and 9.4 fold on target cells, respectively. The results indicate that the cytotoxicity was not further enhanced by the combination scheme. When tumor-bearing nude mice were treated with the different conjugates. Significant inhibition of tumor growth was observed and the survival period of animals was markedly prolonged in comparison with PBS, free HPD and NIgG-HPD treated groups.

Animals↗
PubMed1987

Activated c-Ha-ras oncogene with a guanine to thymine transversion at the twelfth codon in a human stomach cancer cell line.

The rat fibroblast cell line Rat 1 was transfected with total DNA of a gastrocarcinoma cell line, BGC-823. The transforming gene was cloned from the genomic library of the secondary transformants using in situ hybridization with a probe of the human Alu repeat sequence. This cloned gene is homologous to the protooncogene c-Ha-ras. The activation lesion of the transforming gene was identified by sequence analysis as a single nucleotide substitution of thymine for guanine in the 12th codon. This results in the substitution of valine for glycine at the 12th amino acid of the Mr 21,000 protein.

Adenocarcinoma↗
PubMed1987

Molecular cloning and nucleotide sequence analysis of a transforming gene from human gastrocarcinoma cell line.

Mouse and rat fibroblasts were transfected with total DNA from human gastrocarcinoma cell line BGC-823. It was shown by hybridization assay that the genome of one of the rat secondary foci contains transforming genes from the human gastrocarcinoma cell line, which are homologous to the protooncogene c-Ha-ras in the normal cells. The genomic library of the rat secondary foci was constructed, using lambda phage EMBL3 as the vector. The transforming gene Ha-ras of the human gastrocarcinoma cell was thus cloned by screening the library with the probes of human Alu repeat sequence and c-Ha-ras. The nucleotide sequences of the first and second exons were analysed by M13-dideoxy method. The result shows that the nucleotide sequence of the transforming gene is the same as that of the normal protooncogene except one nucleotide difference in the first exon.

Amino Acid Sequence↗
PubMed1977

[The macrophage disappearance reaction in guinea pigs sensitized with bovine gamma globulin or human scrum albumin (author's transl)].

The macrophage disappearance reaction (MDR) is a suitable test for detection of cell mediated immunity against bovine gamma globulin (BGG) and human serum albumin (HSA) in guinea pigs. The MDR is a technical simple, good manipulable, and quantifiable test. The optimal test conditions for the antigens BGC and HSA are the following: Peritoneal exudat cells (PEC) were stimulated with paraffin oil. On the 5th day after receiving oil the animals were injected with 80 microgram BGG or 30 microgram HSA i.p. 5 hours later the PEC were harvested and counted. With the MDR it is possible to detect differences with respect to degree of cell-mediated immunity. Supernatants of sensitized lymphocytes produces the MDR too.

Animals↗
PubMed1995

[Platelet activating factor and pulmonary tuberculosis].

The content of platelet-activating factor (PAF) in plasma, blood, native neutrophils, in the same neutrophils after their incubation with a killed BGC culture and in the incubation medium was measured in 74 patients with various types of active pulmonary tuberculosis. Twelve healthy volunteers formed a control group. PAF was measured by the rabbit platelet aggregation technique. Higher plasma PAF levels were found in half the patients. The highest plasma PAF concentration was observed in the newly revealed patients, in cases with forming cavities in the lung tissue, in those discharged a lot of sputum Mycobacterium tuberculosis, and in those with lymphopenia. PAF content in the native neutrophils of patients was 10 times as high as that in healthy persons. Incubation with the killed BCG culture had no influence on PAF content in the control neutrophils, but greatly increased individual differences in patients. The concentration of PAF in the incubation media of stimulated neutrophils from tuberculosis patients was 3 times higher than in the controls.

Adolescent↗
PubMed1997

[Role of different forms of fibronectin in in vitro bovine follicular development].

This study was aimed at testing the hypothesis that different forms of fibronectin (FN), produced as a consequence of the alternative splicing of the precursor mRNA, play specific roles during follicular development. In particular, we analyzed the presence of the ED-I region, which is absent in the plasma form. Analysis of FN levels in follicular fluids corresponding to different stages of development of bovine follicles revealed marked changes in the concentrations of ED-I + FN whereas total FN levels remained relatively constant. A negative correlation (P < 0.001) was detected between ED-I + FN and estradiol levels. This steroid was without effect on the alternative splicing of FN in primary cultures of bovine granulosa cells. However, cAMP produced a marked decrease in the incorporation of the ED-I region. In contrast, transforming growth factor beta (TGF-beta) elicited both a stimulation on overall FN synthesis and an increase in the inclusion of ED-I. This effect was evident at the protein level (Western blots) and also in the mRNAs (Northern blots). A peptide corresponding to the ED-I region stimulated DNA synthesis in a bovine granulosa cell line (BGC-1) whereas the peptide corresponding to the flanking sequences was without effect. Data presented herein suggest a novel form of regulation by which changes in the primary structure of FN may mediate some of the effects of gonadotropin and intraovarian factors during follicular development.

Animals↗
PubMed1997

[An experimental study of bioactive glass ceramics as orbital implants].

One eyeball of experimental rabbits was enucleated in routine procedure, and then implanted the biocative glass ceramic (BGC). No rejection was observed during the postoperation period. After three months of implantation, they were examined with ultrasound, and a venous-flow-like spectra was detected in the ceramic implant. After six months of implantation, the implans were examined histologically; the ingrowth fibrovascular tissue filled the 90% gaps of the implant. The results suggest that the bioactive glass ceramic implants made in China possess acceptable histocompatibility.

Animals↗
PubMed2026

Tryptophan-driven metabolomic shift in Acidobacteriaceae reveals phytohormones and antifungal metabolites.

UNLABELLED: Acidobacteriota is one of the most abundant phyla in soils and has recently attracted attention for its potential role in promoting phytosanitary benefits. The metabolomic capabilities of this phylum remain poorly characterized, with few experimentally confirmed metabolites described. To address these gaps, we combined untargeted metabolomic profiling with comparative genomic analyses to explore the functional potential of newly isolated Acidobacteriaceae strains. Genome mining across the Acidobacteriota phylum revealed the presence and taxon-specific enrichment of genes associated with plant-related traits, including phytohormone biosynthesis. In parallel, metabolomic analyses of OSMAC-derived extracts uncovered pronounced condition-dependent metabolic variation. Tryptophan supplementation was associated with marked metabolomic reprogramming, including changes in indole-derived metabolites, such as indole-3-acetic acid. Subsequent analyses linked these metabolic shifts to the suppression of phytopathogenic fungi and enabled the identification of malassezindoles and pityriacitrins as active compounds, confirmed by structure elucidation using NMR spectroscopy. Overall, these findings shed light on the previously unexplored metabolic potential of the Acidobacteriota phylum, emphasizing its ecological importance for phytosanitary applications. IMPORTANCE: Despite their ubiquity and genomic diversity, the functional metabolism of members of the Acidobacteriota has largely remained uncharacterized. This study links genomic predictions to experimentally verified metabolomic outputs of Acidobacteriaceae, demonstrating tryptophan-responsive metabolic shifts translating to phytohormones and metabolites suppressing fungal growth. Our work underscores the emerging role of Acidobacteriota as important contributors to soil ecosystem functioning and plant-microbe interactions.

Acidobacteriota↗