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Biomedical subjects

B Hong

Publications and source records attributed to B Hong.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Amplification of C-myc oncogene in squamous cell carcinoma of the larynx].

C-myc amplification in 22 squamous cell carcinomas and 10 normal tissues (control) from the larynx was assessed by dot hybridization technique. Significant amplification of C-myc oncogene was found in malignant tumours as compared with the normal tissues. The extent of amplification also correlated with advanced tumour stages. There was a significant increase in C-myc amplification in TNM stages III and IV when compared with the stages I and II. These data suggested that C-myc oncogene might be activated by gene amplification and it might have a key role in determining the aggressiveness of laryngeal carcinoma.

Carcinoma, Squamous Cell↗
PubMed1993

Limited usage of T cell receptor V beta genes by allopeptide-specific T cells.

T cell reactivity to alloantigens results from direct and indirect recognition of allogeneic MHC molecules and/or peptides. Although direct recognition is not self-MHC restricted, indirect recognition, the result of alloantigen processing and presentation by host APC, is restricted by the self (responder) MHC molecule to which the allopeptide has bound. We have studied the MHC restriction and TCR usage in T cell alloreactivity to a synthetic peptide corresponding to amino acid residues 21-42 of the DR beta 1*0101 molecule. T cell lines were developed by in vitro immunization of T cells from three responders carrying the DR beta 1*1101 allele with this peptide. In all three responders, reactivity to peptide 21-42 was restricted by the DR11 molecule. A limited usage of V beta genes was found in these T cell lines, all of which shared the expression of V beta 13.2. Because indirect recognition of allopeptide may play an important role in chronic, antibody-mediated allograft rejection, study of the TCR gene usage may contribute to the development of specific immunosuppression therapy.

Antibodies, Monoclonal↗
PubMed1993

Differentiation-stage specific self-peptides bound by major histocompatibility complex class I molecules.

We have tested the hypothesis that phenotypic changes of development are accompanied by expression of differentiation-stage specific peptides bound to major histocompatibility complex (MHC) class I molecules. The U937 cell line, when cultured in the presence of phorbol myristate acetate (PMA), undergoes differentiation from monoblasts to macrophage-like cells. The high-performance liquid chromatography profile of peptides eluted from purified human histocompatibility leukocyte antigen class I molecules expressed by U937 treated with PMA differs from that obtained from control, untreated U937 cells. Chemical sequencing of eluted peptides identified a peptide derived from cytomegalovirus in both treated and untreated cells. PMA-treated, but not untreated cells, displayed an additional peptide derived from interleukin 1 beta. Hence, differentiation-induction of U937 is accompanied by the presentation of at least one differentiation-stage specific peptide. Our results indicate that, similar to viral infection, cellular development and transformation is accompanied by the de novo synthesis of proteins which are processed and presented on MHC class I molecules.

Amino Acid Sequence↗
PubMed1992

Biomechanical effect of a two-segment anterior cruciate ligament graft with separate femoral attachments and differing levels of prescribed load sharing.

The objective of this study was to analyze the biomechanical effect of varying the level of prescribed load sharing between two segments of an anterior cruciate ligament (ACL) graft, and of separating the femoral attachments of these segments. Total anterior-posterior (AP) laxity was measured using an instrumented spatial linkage. Forces in graft segments were measured using buckle transducers. The two-segment graft was formed using the middle third of the patellar tendon with bone blocks and a synthetic augmentation device. Proximal fixation was obtained using a fixture which allowed changing the individual locations of the femoral attachments of the tendon and augmentation segments. Distal fixation was achieved using a force-setting device which allowed the loads in each segment to be set to prescribed levels. Total graft force, load sharing, and total AP laxity were recorded during the application of 100-N AP tibial loads at 0 degrees, 30 degrees, 60 degrees, 90 degrees, and 110 degrees flexion, for various combinations of load sharing set at extension and locations of femoral attachment sites. The load sharing, total graft force, and AP laxity during AP loading at the five test flexion angles were not significantly affected by changing the prescribed level of load sharing set at extension for a given femoral attachment configuration. However, varying the separate hole locations of the graft segments for a given level of load sharing significantly affected load sharing, total graft force, and AP laxity. If the tendon graft was located posteriorly (on the medial surface of the lateral femoral condyle) and the augmentation segment proximally, the augmentation carried a greater portion of the total force in flexion. If the augmentation segment was changed to a more posterosuperior location and the tendon posteroinferior, the tendon carried a higher percentage of the total force in flexion. AP laxity in most reconstruction states was significantly greater than in the normal joint with an intact ACL. The nature of the load sharing between the graft segments under AP tibial load over the flexion range can be controlled by the appropriate choice of the segments' femoral attachment locations.

Analysis of Variance↗
PubMed1992

Developmental and organ-specific expression of an ABA- and stress-induced protein in barley.

An mRNA species, HVA1, has been shown to be rapidly induced by abscisic acid (ABA) in barley aleurone layers (Hong, Uknes and Ho, Plant Mol Biol 11: 495-506, 1988). In the current work we have investigated the expression of HVA1 in other organs of barley plants. In developing seeds, HVA1 mRNA is not detected in starchy endosperm cells, yet it accumulates in aleurone layers and embryo starting 25 days after anthesis, and its level remains high in these organs in dry seeds. Although the levels of HVA1 mRNA are equivalent in the dry embryos of dormant and nondormant barley seeds, upon imbibition HVA1 mRNA declines much slower in the dormant than in the nondormant embryos. The HVA1 mRNA and protein levels are highly induced by ABA treatment in all organs of 3-day-old seedlings. However, the induction in the leaf of 7-day-old seedlings is less than one tenth the level observed in the leaf of 3-day-old seedlings. In the leaf, HVA1 mRNA and protein are induced mainly at the base. These observations indicate that the expression of HVA1 is under developmental regulation. Besides the HVA1 protein, a smaller protein (p20) of approximately 20 kDa cross-reacting with anti-HVA1 polyclonal antibodies, is induced by ABA in barley seedlings but not in seeds. HVA1 mRNA is induced by drought, NaCl, cold or heat treatment. Similar to ABA treatment, the drought induction of HVA1 occurs in all the tissues of 3-day-old seedlings, but the induction decreases dramatically in the leaf of 7-day-old plants. The significance of organ-specific, developmentally regulated, and stress-induced expression of HVA1 is discussed.

Abscisic Acid↗
PubMed1992

[Prognostic significance of nuclear DNA measurement with flow cytometry for laryngeal squamous cell carcinomas].

DNA ploidy, S% and proliferative index (PI) of carcinomatous cell were evaluated with FCM in 41 patients with laryngeal primary squamous cell carcinomas which were operated on in our department during the period between Jan. 1979 to Oct. 1987. The results showed that DNA aneuploidy was identified in 65.85% of the cases (27/41) and patients with aneuploid carcinomas had higher S% (mean +/- standard: 23.22 +/- 9.57%), higher PI (mean +/- standard: 37.59 +/- 9.57%) and higher rate of relapse and/or metastasis than those with diploid tumours (55.55% vs 11.77%, P < 0.025). Patients with aneuploid carcinomas also correlated with an unfavorable prognosis compared with those with diploid tumors. Cases with aneuploid and diploid carcinomas had 66.11% and 92.86% respectively for two years postoperation survival rate; 46.74% and 92.86% respectively for five years postoperation survival rate (Log-rank test: chi 2 = 5.96, P < 0.025). We conclude that nuclear DNA measurement with flow cytometry is of important significance in estimating prognosis and guiding treatment for laryngeal squamous cell carcinomas.

Aged↗
PubMed1992

[Estrogen and progesterone receptors in laryngeal carcinoma].

The existence of hormone receptors on or within neoplastic tissue has potential diagnostic, therapeutic, and prognostic importance. It has now been demonstrated in many reports that cancers of the breast and prostate often express hormone receptors and can be controlled by hormone manipulation. The fact that larynx is a target organ for androgenic steroids has long been known. The question of whether laryngeal carcinoma expresses hormone receptors has been a matter of interest. We adopted the fluorescent hormone conjugate method to measure the estrogen receptor (ER) and progesterone receptor (PR) in 25 patients with laryngeal cancer. Our findings indicated that in 25 samples of laryngeal cancer 48% were ER positive, and 68% were PR positive. Cells of the laryngeal cancer not only contain ER and PR but also have relationship between the presence of receptors and the degree of histologic differentiation. Low differentiated cancers are inclinable to contain low level receptors. From this initial survey it appears that the hormone receptors could play an important role in the cancer of larynx. The presence of receptors in some laryngeal carcinoma implicates that these tumors are possibly hormone sensitive.

Adult↗
PubMed1990

[Diagnosis value of lateral pharyngeal roentgenography in snoring disease].

In this paper, X-ray findings of the lateral pharynx before uvulopalatopharyngoplasty in 14 cases of snoring disease were studied. The results are as follows. There is less than 5 mm in anterior-posterior airway of pharyngeal cavity (13 cases), and 8 mm (1 case), in diameter. Minimum 2 mm, average 4.4 mm. There is less than 25 mm length of uvula (7 cases), 28-35 mm (7 cases). Minimum 22 mm, average length is 27.9 mm. Shape of uvula is thick and long (12 cases), thick and short 1 case, thin and long 1 case. The etiology, abnormal X-ray finding and X-ray examination of the lateral pharynx, etc. in snoring disease have been discussed.

Adult↗