[Ion-selective microelectrodes: principle and application of in vivo measurements of ionic concentrations in cochlear endolymph]

OBJECTIVE

To introduce the method of making neutral carrier ion-selective microelectrode and use it for in vivo measurement of ionic concentrations in cochloear endolymph.

METHODS

GG-17 glass capillaries with 1.85 mm O.D. were rinsed extensively and dried in an oven. Two capillaries were parallelly connected and pulled with microelectrode puller to make a double-barreled micropipette. One barrel was back-filled with ion exchanger and internal reference solution, which served as ionic potential electrode, while the other barrel filled with 150 mmol/L KCL as reference electrode. Each barrel of microelectrode was connected to differential electrometer via Ag-AgCl wire and output was recorded on a three-channel recorder. Every ion-selective microelectrode was calibrated in a series of standard solutions to determine the required characteristics. Twenty healthy guinea pigs with normal hearing were anesthetized and were artificially respired through the tracheal canal after the intramuscular injection of suxamethonium chloride. The tympanic bulla was exposed and a double-barreled ion-selective electrode was inserted into the scala media through the round window and basilar membrane. The ionic potentials and endocochlear potentials (EP) were simultaneously recorded from the basal turn of the cochlea. Ionic concentrations were then calculated by Nicolsky-Eisenman equation.

RESULTS

The concentrations of potassium, sodium and calcium ions in the cochlear endolymph were 146.3 +/- 11.8 mmol/L, 0.36 +/- 0.22 mmol/L and 16.2 +/- 5.7 micromol/L, respectively.

CONCLUSIONS

The neutral carrier ion-selective microelectrode made with the above method is reliable and therefore can be used for accurately measuring the ionic concentrations of microenvironment in vivo continuously and transiently.

Filtroporation: A simple, reliable technique for transfection and macromolecular loading of cells in suspension

Cultured Chinese hamster ovary (CHO) cells suspended in their growth medium were forced by gas pressure through the uniformly sized micropores of filter membranes. This procedure caused transient damage to the plasma membrane, which increased the permeability of the cells to exogenous molecules. This "filtroporation" was indicated by uptake of fluorescent dextran molecules up to 500,000 MW in cells deemed viable by trypan blue dye exclusion. The macromolecular uptake was increased if the driving pressure was increased at constant micropore size, or if the micropore size was decreased at constant driving pressure. Larger membrane perturbations permitted uptake of a luciferase reporter plasmid, which resulted in transfection of the CHO cells with the surviving cells expressing luciferase activity after 2 days in culture. This simple and general new method of porating cells in suspension may be optimized to incorporate the desired macromolecules while retaining the maximum viability.

BjuA03.BNT1 plays a positive role in resistance to clubroot disease in resynthesized Brassica juncea L

Clubroot has become a major obstacle in rapeseed production. Breeding varieties resistant to clubroot is the most effective method for disease management. However, the clubroot-resistant germplasm of rapeseed remains limited. To tackle this challenge, we synthesized the clubroot-resistant mustard, CT19, via distant hybridization, and subsequently an F2 segregating population was created by intercrossing CT19 with a clubroot-susceptible germplasm CS15. A major-effect clubroot resistance QTL qCRa3-1 on chromosome A03 was identified through QTL scanning. Transcriptome analyses of CT19 and CS15 revealed that the mechanisms conferring resistance to Plasmodiophora brassica likely involved the regulation of flavonoid metabolism, fatty acid metabolism, and sulfur metabolism. By combining the results from transcriptome, QTL mapping, and gene sequencing, a candidate gene BjuA03.BNT1, encoding NLR (nucleotide-binding domain leucine-rich repeat-containing receptors) protein, was obtained. Intriguingly, comparing with CT19, a base T insertion was discovered in the BjuA03.BNT1 gene's coding sequence in CS15, resulting an alteration within the LRR conserved domain. Overexpression of BjuA03.BNT1 from CT19 notably enhanced the resistance to clubroot in Arabidopsis. Our investigations revealed that BjuA03.BNT1 regulated the resistance to clubroot by modulating fatty acid synthesis and the structure of cell wall. These results are highly relevant for molecular breeding to improve clubroot resistance in rapeseed.

Molecular cloning of chick cardiac muscle tensin. Full-length cDNA sequence, expression, and characterization

Here we describe the molecular cloning of 7.1-kilobase cDNA encoding chick cardiac muscle tensin. It contains an open reading frame of 1,744 amino acid (aa) residues. Sequence analysis reveals that, in addition to the previously noted SH2 domain (Davis, S., Lu, M. L., Lo, S. H., Lin, S., Butler, J. A., Druker, B. J., Roberts, T. M., An, Q., and Chen, L. B. (1991) Science 252, 712-715), tensin contains virtually all of the known sequence (362 aa) of insertin, an actin-capping protein that allows actin monomer to be "inserted" (Schroer, E., and Wegner, A. (1985) Eur. J. Biochem. 153, 515-520). Moreover, tensin shares partial homology with actin (46.7% identity in 30 aa), beta-spectrin's actin-binding consensus (40% identity in 26 aa), BCR (40% identity in 25 aa), catenin alpha (35% identity in 45 aa), synapsin Ia (25.6% identity in 156 aa), IL-3 receptor (20.2% identity in 384 aa), and IL-2/EPO receptors (14% identity in 20 aa). Recombinant full-length tensin, tagged with an influenza-derived epitope, was over-expressed by a baculovirus system and purified to apparent homogeneity. It migrates as a 200-kDa protein in SDS-polyacrylamide gel electrophoresis, similar to the native tensin. The structure of the tensin molecule has been characterized by light scattering, electron microscopy, and gel filtration. Nine monoclonal antibodies recognizing different regions of tensin have been prepared and characterized. The epitope-tagged recombinant tensin gene was subcloned into a pRcCMV vector and transfected into NIH 3T3 cells. Immunofluorescence stainings with monoclonal antibodies specific for chick tensin (not cross-reactive with mouse tensin) showed that the expressed protein is indeed localized at focal contacts, as that of native tensin.

[Studies on arachidonic acid production by Mortierella]

The effects of the incubation temperature, initial pH of the medium, carbon source and nitrogen source on the production of arachidonic acid by Mortierella sp. M10 were studied. Thought orthogonal experiments, the optimum culture medium was obtained (g/L): glucose, 100; yeast extract, 10; KNO3, 4.0; KH2PO4, 2.0; CaCl2.2H2O, 0.1; MgSO4.7H2O, 0.5; FeCl3.6H2O, 0.015; ZnSO4.7H2O, 0.0075; CuSO4.5H2O, 0.0005. Under the optimum culture conditions, the dry cell weight and arachidonic acid was 33.51 g/L and 0.827 g/L, respectively. The flask culture process was analysed.

[Targeted immunotherapy efficacy analysis in patients with relapsed/refractory B cell acute lymphocytic leukemia]

Objective: Comparison of conventional chemotherapy and immunotargeted therapy efficacy in patients with relapsed/refractory (R/R) acute B cell leukemia (B-ALL) . Methods: The clinical data of 212 patients with R/R B-ALL in the Affiliaed Cancer Hospital of Zhengzhou University from January 2008 to July 2020 were analyzed retrospectively to compare the response rate and survival time difference between conventional chemotherapy and immunotargeted therapies (antiCD19 CAR-T and CD3CD19 bi-specific antibody blinatumomab) , and to explore the related factors affecting prognosis. Results: The CR rate of patients with R/R B-ALL treated with anti-CD19 CAR-T cells was 80.4% , patients treated with blinatumomab was 62.5% , and patients treated with chemotherapy was 38.6% . There was significant difference in the CR rate among the three therapies (P<0.001) . CAR-T cells 1-year OS rate was 41.5% , which was significantly higher than that of the chemotherapy group (10.3% ) (P<0.001) . The 1-year PFS rate of CAR-T cells (30.1% ) was also significantly higher than that of the chemotherapy group (9.7% ) (P<0.001) . The median OS of patients with bridging allo-HSCT after CR treatment by CAR-T cells was 18.5 months, which was higher than that of patients without allo-HSCT (8 months) (P=0.027) . The median PFS of patients with allo-HSCT was 17 months, which was higher than that of patients without allo-HSCT (4 months) (P=0.001) . The 1-year OS rate of patients treated with blinatumomab was 14.3% , which was higher than that of the chemotherapy group (10.3% ) (P=0.018) . The 1-year PFS rate (14.6% ) was also higher than that of the chemotherapy group (9.7% ) (P=0.046) . The median OS and median PFS of patients with bridging allo-HSCT were 13 and 11 months, respectively, which was higher than that of patients without allo-HSCT (9.5 and 6 months) . The cytokine release syndrome (CRS) incidence in patients with R/R B-ALL treated with anti-CAR-T cells was 89.8% . Grades 3-4, grade 2, and grade 1 CRS were experienced by 30.2% , 11.3% and 58.5% patients, respectively. Only three patients (37.5% ) with blinatumomab developed CRS, all of which were grade 1. Conclusion: The response rate and survival rate of patients with R/R B-ALL treated with CD19 CAR-T cells and blinatumomab were significantly better than those treated with conventional chemotherapy.

HRad17, a human homologue of the Schizosaccharomyces pombe checkpoint gene rad17, is overexpressed in colon carcinoma

Using the palindromic PCR-cDNA display method, we have cloned a novel gene overexpressed by human colon carcinoma relative to normal colon. Among normal tissues examined, only testis expresses it at a high level. Sequence analysis revealed its extensive homology with checkpoint genes rad17 of Schizosaccharomyces pombe and RAD24 of Saccharomyces cerevisiae. This novel gene designated as hRad17 is localized to chromosome 5q12,13.1, a region known to be deleted in a variety of human cancers. Promoter region and one pseudogene of hRad17 have been identified. Whereas the increased expression of hRad17 by human colon carcinomas may be related to the known resistance of these cells to DNA-damaging agents during therapy, the deletion of hRad17 in a variety of cancers may predispose them to increased rate of mutation and heightened sensitivity to DNA-damaging agents, including radiation and anticancer drugs.

Brain nitric oxide synthase expression is enhanced in the human cervix in labor

OBJECTIVES

To determine whether brain nitric oxide synthase (bNOS) is expressed in human cervix, define its localization, and examine the possibility that it contributes to the nitric oxide (NO) pool and has a role in human cervical ripening.

METHODS

Human cervical biopsy tissues were collected from four groups: (1) nonpregnant patients, (2) term nonlabor (cesarean delivery) patients, (3) term labor patients with cesarean deliveries, and (4) term labor patients (vaginal delivery). The mRNA expression was assessed using reverse-transcribed polymerase chain reaction and in situ hybridization. The protein expression was determined using Western blot and its localization was shown using immunostaining.

RESULTS

Both bNOS mRNA and protein are present in human cervical tissue. They were localized to stroma cells and epithelial cells by in situ hybridization and immunostaining. bNOS protein expression in the labor group was significantly higher than in the nonlabor group (P <.05).

CONCLUSION

bNOS is expressed in the human cervix and enhanced expression is observed in labor, suggesting its possible role in contributing to the NO pool in the human cervix, in cervical ripening, and in labor.