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Biomedical subjects

M M Chou

Publications and source records attributed to M M Chou.

44 records · Page 3Linked to original sources

Prenatal diagnosis of placenta previa/accreta with color Doppler ultrasound.

A case of placenta previa/accreta was diagnosed at 23 weeks' gestation using color Doppler ultrasound. Imaging showed an unusually intense blood flow within the placental sonolucent spaces and the hypervascularization patterns within the placental and the non-placental tissues. Highly pulsatile venous flow patterns were detected within the placental blood lakes and the subplacental venous complex. A strong association between the lacunar flow pattern and the abnormally adherent placentation was confirmed by the color Doppler sonographic findings.

Journal Article↗

Early prenatal diagnosis of type III bilateral congenital cystic adenomatoid malformation of the lung.

We present a case of type III fetal cystic adenomatoid malformation with bilateral total involvement of the lungs. The characteristic sonographic findings are echogenic homogeneous lung mass, fetal ascites and placentomegaly. The early diagnosis at 16 weeks' gestation allows the elective termination of pregnancy because of the likely fatal prognosis. To our knowledge, this is the earliest reported case of congenital cystic adenomatoid malformation of the lung that has been detected prenatally.

Journal Article↗

The SH2- and SH3-containing Nck protein transforms mammalian fibroblasts in the absence of elevated phosphotyrosine levels.

We have established the human nck sequence as a new oncogene. Nck encodes one SH2 and three SH3 domains, the Src homology motifs found in nonreceptor tyrosine kinases, Ras GTPase-activating protein, phosphatidylinositol 3-kinase, and phospholipase C-gamma. Overexpression of human nck in 3Y1 rat fibroblasts results in transformation as judged by alteration of cell morphology, colony formation in soft agar, and tumor formation in nude BALB/c mice. However, overexpression of nck does not induce detectable elevation of the phosphotyrosine content of specific proteins, as is observed for v-crk, another SH2/SH3-containing oncogene. Despite this fact, we demonstrate that Nck retains the ability to bind tyrosine phosphorylated proteins in vitro, using a fusion protein of Nck with glutathione-S-transferase (GST). Moreover, when incubated with lysates prepared from v-src-transformed 3Y1 cells or the nck-overexpressing cell lines, GST-Nck binds to both p60v-src and serine/threonine kinases, respectively. Although phosphotyrosine levels are not elevated in the nck-expressing fibroblasts, vanadate treatment of these cells results in a phosphotyrosine pattern that is altered from the parental 3Y1 pattern, suggestive of a perturbation of indigenous tyrosine kinase pathways. These results suggest the possibility that human nck induces transformation in 3Y1 fibroblasts by virtue of its altered affinity or specificity for the normal substrates of its rat homolog and that Nck may play a role in linking tyrosine and serine/threonine kinase pathways within the cell.

Adaptor Proteins, Signal Transducing↗

[Clinical experience of GDM screening program].

From Jan. 1985 to Jun. 1990, 2561 pregnant women attending our prenatal clinic were screened for gestational diabetes. A 50-gm, 1-hour glucose challenge test was given and 470 patients (18.4%) showed plasma glucose values greater than or equal to 140 mg/dl. These women were subjected to a further 3-hr 100-gm OGTT to diagnose diabetes using O'Sullivans' criteria. Of these 470 cases, 80 (3.1%) of total cases were shown to be diabetic. Strict glycemic control with a fasting plasma sugar under 105 mg/dl and postprandial sugar under 120 mg/dl was conducted using diet and insulin in all cases. We compared the perinatal outcome of GDM pregnant women with normal pregnant women. Statistically, there was no significant difference. This study clearly demonstrates that a GDM screening program should be recommended for every pregnant woman. Prompt glycemic control should be given for all diabetic mothers to optimize the perinatal outcome.

Adult↗

Polymeric sequences reveal a functional interrelationship between hydrophobicity and length of signal peptides.

We have examined the hydrophobicity component of signal peptide function using polymeric sequences in combination with cassette mutagenesis. Using homopolymeric units of either isoleucine, leucine, valine or alanine to replace the natural core segment of the Escherichia coli alkaline phosphatase signal peptide, the hydrophobicity requirements for export and processing were delineated. The transport properties of these mutants demonstrated that the net hydrophobicity determines the total extent of precursor processing, while a high mean hydrophobicity/residue is critical for complete, rapid processing and translocation. Moreover, alkaline phosphatase was converted from a periplasmic to an active membrane-anchored protein via a signal containing 20 leucine residues. This application of polymeric sequences allows systematic comparisons to be made, unambiguously revealing the hydrophobicity requirements governing specific steps in the transport process.

Alkaline Phosphatase↗

Preventing complications from lines and tubes.

Rather than providing an exhaustive list of known complications of all tubes and lines used in the NICU, we have highlighted the potentially traumatic nature of their use and outlined general principles of prevention. Most complications of care are more easily avoided if we know about them in advance. Attention to simple details, while recognizing that use of indwelling tubes and lines has both benefits and hazards, should lessen some of these morbidities.

Catheterization↗

Correlation between Helicobacter pylori infection and gastrointestinal symptoms in pregnancy.

Nausea, vomiting, and other dyspeptic symptoms are common in pregnancy. This hospital-based, cross-sectional study was designed to determine the role of Helicobacter pylori infection in gastrointestinal (GI) symptoms during pregnancy. Standardized verbal scales were used to evaluate the frequency and severity of GI symptoms in 54 women whose pregnancies were in the first 16 gestational weeks. H. pylori infection was defined as a positive serum immunoglobulin G result on an immunochromatographic assay. The H. pylori seropositivity rate was higher in the pregnant women (69%) than in the general population (approximately 50%-55%), but seropositivity did not correlate with clinical symptoms. Moreover, no specific patterns of GI symptoms were uncovered in the H. pylori-infected patients. Maternal age, body weight, parity, gestational week, and educational level were not associated with H. pylori infection; neither were the prevalence and severity of GI symptoms.

Adult↗