Biomedical subjects

M L Yang

Publications and source records attributed to M L Yang.

48 records · Page 3Linked to original sources

PubMed1991

Managements of placenta accreta.

From January 1986 to June 1990 at Veterans General Hospital-Taipei, 12 cases of placenta accreta were reviewed. The incidence were 1 per 1,101 deliveries. Eight cases were confirmed by pathological examination, and the incidence was 0.06% (1/1,652). Placenta previa was found in 7 cases (58.3%); 6 of them had history of cesarean section. All the cases had history of uterine surgery. Seven cases underwent cesarean section, and the other one received myomectomy. Hysterectomy was performed on 6 patients, and conservative treatments were employed on the other 6 cases. No maternal mortality occurred. Besides one case of missed abortion, there was only one perinatal loss due to immaturity. Accurate prenatal diagnosis of placenta accreta by ultrasound was obtained in 4 cases. Although hysterectomy is the definite treatment of placenta accreta, conservative managements should be tried before this intervention.

Adult↗

PubMed1991

Amino acid sequence of rabbit apolipoprotein E.

The complete amino acid sequence of rabbit apolipoprotein E (apoE) was determined by generating three sets of peptides using cyanogen bromide, endoproteinase AspN, and Staphylococcus aureus V8 protease to cleave the protein. Through twenty cycles of sequence analysis on the whole protein, glutamic acid was identified as the N-terminal residue of rabbit apoE; the C-terminus of the protein was identified as glutamine. Based on the sequence of 294 amino acid residues determined by protein structure analysis, the molecular weight of rabbit apoE was determined to be 33,684. The protein sequence differed from the cDNA inferred sequence in 19 positions, only one of which could be attributed to microheterogeneity. The corrected amino acid sequence of rabbit apoE shares 80% homology with the human apoE sequence, 4% greater homology than that inferred from the cDNA sequence. The great similarity in the amino acid sequences of human and rabbit apoE suggests that their physical and physiological properties may also be similar. This homology and the relative ease with which apoE is isolated from rabbit plasma make it possible to conduct some in vitro experiments with the rabbit apoprotein that would have direct relevance to human apoE, but would be difficult or impossible with the human counterpart because of the quantity of protein required.

Amino Acid Sequence↗

PubMed1990

Isolation and characterization of sulfhydryl and disulfide peptides of human apolipoprotein B-100.

Twenty-three of the 25 cysteine residues in apolipoprotein B-100 have been isolated directly from tryptic or peptic peptide mixtures. Sixteen cysteine residues exist in disulfide forms: Cys-1-Cys-3, Cys-2-Cys-4, Cys-5-Cys-6, Cys-7-Cys-8, Cys-9-Cys-10, Cys-11-Cys-12, Cys-13-Cys-14, and Cys-20-Cys-21. All of these except Cys-20-Cys-21 are recently discovered disulfide linkages. In addition to Cys-22 and Cys-24, which have been described as sulfhydryls on low density lipoprotein, Cys-15 to Cys-18 and Cys-23 are in the reduced form. Cys-19 and Cys-25 are not yet confirmed. Our results revealed that all identified disulfide linkages are located in the trypsin-releasable regions and that all except Cys-1-Cys-3 and Cys-2-Cys-4 are linked to the neighboring cysteine. We propose a linear model of apolipoprotein B-100 in low density lipoprotein that wraps around the low density lipoprotein molecule.

Amino Acid Sequence↗

PubMed1989

Dietary calcium and development of hypertension in spontaneously hypertensive rats.

The purpose of the present study was to attempt to correlate four calcium diets (0.02, 0.1, 0.5 and 2.5%) with changes in the development of hypertension in both spontaneously hypertensive and Wistar-Kyoto rats. Our findings confirm that an inverse relationship exists between dietary calcium content and the development of hypertension. The relationship does not rely upon altered serum ionized sodium, potassium, or calcium or parathyroid hormone levels. In addition, no consistent dietary calcium-dependent changes were noticed in cardiovascular reactivity. In contrast, anesthesia with pentobarbital completely abolished the relationship. These data support the hypothesis that dietary calcium influences autonomic tone through some, as yet, undefined processes.

Animals↗

PubMed1989

[Basal cell carcinoma and mast cells].

The histology of 17 cases of basal cell carcinoma and dermis next to the carcinoma was observed. The results showed that the mast cell number was markedly increased in the dermis near the basal cell carcinoma. There was an increase in the collagen fibers between the carcinoma and dermis tissues, forming a thin membrane around the carcinoma tissue. These findings suggest that the carcinoma-associated antigen may activate the lymphocytes to produce certain lymphokine which stimulates the proliferation and differentiation of the mast cell precursors. Histamine and other active mediators released from mast cells stimulate fibroblasts to synthesize collagen fibers which form a thin membrane between the carcinoma and dermis. The membrane plays a protective role against tumor dissemination.

Biopsy↗

PubMed1988

Interaction of B16 malignant melanoma tumor cells with the murine mesentery in vitro.

We have used organs cultures of murine mesentery as a model system to investigate the mechanisms by which B16-F10 melanoma cells invade normal tissues. The mesentery has the advantage of being a real tissue, consisting of a loose connective tissue, containing a normal complement of stromal cells and extracellular matrix, covered by a continuous epithelium of squamous mesothelial cells which are separated from the connective tissue by a laminin-containing basement membrane. B16-F10 cells seeded onto the mesentery in vitro cause a local retraction of the mesothelial cells exposing the underlying basement membrane onto which the tumor cells spread. Direct contact between the tumor cells and the margins of the mesothelial cells is required to induce retraction. Most of the B16 cells remain on the surface of the mesentery where they spread on the basement membrane without disrupting it. A few B16 cells penetrate the basement membrane and invade the connective tissue interior of the mesentery where they flatten out and assume a fibroblastic morphology. Tumor cells within the connective tissue may continue to translocate and they adhere to and move along the fibers of the connective tissue extracellular matrix without appearing to destroy or disrupt them.

Animals↗

PubMed1988