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Biomedical subjects

G J Song

Publications and source records attributed to G J Song.

11 recordsLinked to original sources
PubMed2001

Mutation screening of the FSH receptor gene in infertile men.

Follicle stimulating hormone (FSH) is important for controlling spermatogenesis through binding with its receptor. However, little information is available on mutations of the FSH and its receptor gene in infertile men. To study the genetic defects, which caused problems in spermatogenesis, we screened the point mutations of the FSH receptor gene in infertile men with high serum FSH concentrations. Seventy male infertile patients with high FHS levels (> 12 mIU/ml) were screened for mutations in each of the 10 exons of the FSH receptor gene, using genomic DNA PCR and a single-strand conformation polymorphism (SSCP) analysis. From this study, three shifted bands were detected by SSCP. The first shifted band was found in the PCR product of exon 4, including the exon-intron boundary sequence in only one patient. The sequence analysis revealed a nucleotide A to T substitution in intron 3 (IVS3-4A-->T). The second shifted band was detected in exon 10 with high frequency (33%). A nucleotide A to G substitution was found at the position of the 994th nucleotide, predicting a Thr to Ala substitution at the position of the 307th amino acid (Thr307Ala). The third shifted band in the 3' region of exon 10 was detected frequently in infertile patient and normal groups. It was tightly linked to the Thr307Ala variant. Thus, all of the abnormalities represent neutral polymorphisms, and not pathological mutations of the FSH receptor gene. In conclusion, we did not confirm that the genomic mutation of the FSH receptor is a major genetic cause in Korean infertile patients with high FSH levels.

Follicle Stimulating Hormone↗
PubMed2000

Expression pattern of germ cell-specific genes in the testis of patients with nonobstructive azoospermia: usefulness as a molecular marker to predict the presence of testicular sperm.

OBJECTIVE: To analyze the expression pattern of testis-specific genes of patients with various spermatogenic defects and their usefulness as a molecular marker to predict the presence of testicular spermatozoa in patients with nonobstructive azoospermia undergoing IVF. DESIGN: Prospective, controlled study. SETTING: Hospital-based infertility research laboratory. PATIENT(S): Fifty-eight men with azoospermia or severe oligozoospermia. INTERVENTION(S): Testicular biopsy was done in the patients with obstructive or nonobstructive azoospermia, including Sertoli cell-only syndrome, maturation arrest, severe hypospermatogenesis, and normal spermatogenesis. MAIN OUTCOME MEASURE(S): Reverse transcriptase polymerase chain reaction was performed using 1 microgram of total RNA extracted from testicular tissues. Three pairs of primers were used for amplification of male germ cell-specific genes (DAZ, transcribed in male germ cells; PGK2, in late spermatocytes and spermatids; protamine-2, in spermatids) as molecular markers. Testicular sperm was obtained by multiple testicular sperm extraction. RESULT(S): The DAZ, PGK2, and protamine-2 genes were expressed in 38, 30, and 21 of the 43 patients with nonobstructive azoospermia, respectively. Testicular spermatozoa were successfully extracted in 4 of 43 patients with nonobstructive azoospermia with the use of multiple testicular sperm extraction. Detection of protamine-2 transcripts predicted the presence or absence of spermatozoa in the testicular tissue in 39 of 43 patients (91%). CONCLUSION(S): Expression of the protamine-2 gene may be a useful molecular marker to predict the presence of testicular sperm in patients with nonobstructive azoospermia.

Adult↗
PubMed1997

The effects of the cholesterol ester transfer protein gene and environmental factors on the plasma high density lipoprotein cholesterol levels in the Korean population.

The cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that transfers neutral lipids between plasma lipoproteins. The distribution of variations in the CETP gene and their influences on lipid levels were investigated among random members of the Korean population (n = 270) whose profiles of environmental factors were known. The frequencies of the major allele at BamHI, EcoNI, TaqIA, TaqIB, New HinfI RFLPs, and the D442G mutation were 0.77, 0.55, 0.84, 0.62, 0.81, and 0.94, in serial order. The significant associations of the BamHI RFLP and the D442G mutation with the plasma high density lipoprotein (HDL) cholesterol levels were observed in this population. Subjects with genotype B2B2 of the BamHI RFLP had significantly lower HDL cholesterol levels than the mean of total subjects. Subjects with D442G mutant allele had a significantly higher HDL cholesterol levels only in males. Analysis of the covariance model (ANOCOVA) showed that allelic variations in the BamHI RFLP and the D442G mutation sites accounted independently for 4.0 and 5.9% of the total inter-individual variation in plasma HDL cholesterol in males (F = 2.29, p = 0.10; F = 3.4, p = 0.03). The effect of the CETP genotype was very high (about 10%), compared to the total effects of sex, body mass index, age, and smoking habit (20%). In conclusion, the genetic variation of the CETP gene is related to the regulation of plasma HDL cholesterol levels and the extent of the effect seems to be different between male and female in the Korean population.

Adult↗
PubMed1997

Two partial deletion mutations involving the same Alu sequence within intron 8 of the LDL receptor gene in Korean patients with familial hypercholesterolemia.

Twenty-eight unrelated persons heterozygous for familial hypercholesterolemia (FH) were screened to assess the frequency and nature of major structural rearrangements at the low-density lipoprotein (LDL) receptor gene in Korean FH patients. Genomic DNA was analyzed by Southern blot hybridization with probes encompassing exons 1-18 of the LDL receptor gene. Two different deletion mutations (FH29 and FH110) were detected in three FH patients (10.7%). Each of the mutations was characterized by the use of exon-specific probes and detailed restriction mapping mediated by long-PCR (polymerase chain reaction). Mutation FH29 was a 3.83-kb deletion extending from intron 6 to intron 8 and FH110 was a 5.71-kb deletion extending from intron 8 to intron 12. In FH29, the translational reading frame was preserved and the deducible result was a cysteine-rich A and B repeat truncated protein that might be unable to bind LDL but would continue to bind beta-VLDL. FH110 is presumed to be a null allele, since the deletion shifts the reading frame and results in a truncated protein that terminates in exon 13. Sequence analysis revealed that both deletions have occurred between two Alu-repetitive sequences that are in the same orientation. This suggested that in these patients the deletions were caused by an unequal crossing over event following mispairing of two Alu sequences on different chromatids during meiosis. Moreover, in both deletions, the recombinations were related to an Alu sequence in intron 8 and the deletion breakpoints are found within a specific sequence, 27 bp in length. This supports the hypothesis that this region might have some intrinsic instability, and act as one of the important factors in large recombinational rearrangements.

Adolescent↗
PubMed1994

Exercise electrocardiography and aortic Doppler velocimetry in asymptomatic identical twins discordant for type 1 (insulin dependent) diabetes.

OBJECTIVE: To determine the influence of insulin dependent diabetes on the prevalence of myocardial ischaemia and on global left ventricular systolic performance. DESIGN: Stress treadmill electrocardiograms and simultaneous Doppler measurement of aortic maximum acceleration were obtained during exercise on symptom free subjects. The electrocardiograms were scored blindly according to the Minnesota code. PARTICIPANTS: 39 identical twin pairs (22 male) discordant for insulin dependent diabetes and 39 non-diabetic controls of similar age and sex were examined. The twins and controls had a mean age of 37 (range 25-69) with a mean (SD) duration of diabetes in the diabetic twin of 17 (7) years. Those selected were normotensive and had no renal impairment. RESULTS: Systolic blood pressure was significantly higher in the diabetic twins than in their non-diabetic cotwins both at rest (p < 0.05) and at peak exercise (p < 0.01). Electrocardiographic evidence of ischaemia was not correlated within twin pairs and was found in similar numbers of diabetic twins, their non-diabetic cotwins, and control subjects. Abnormal electrocardiograms were found in a similar number of diabetic twins (23%), non-diabetic cotwins (18%), and controls (15%). There was a significant correlation in Doppler measurements of global left ventricular systolic function within the identical twins; no significant difference was found for these Doppler measurements in the diabetic twins, non-diabetic cotwins, or controls. CONCLUSION: Exercise characteristics and cardiac function seem to be subject to shared genetic or shared environmental influences or both, whereas electrocardiographic features of ischaemia seem to be environmentally determined. In a selected cohort of diabetic identical twins without evidence of nephropathy there was no evidence that diabetes influenced the prevalence of myocardial ischaemia or global left ventricular systolic function.

Adult↗
PubMed1991

An echocardiographic assessment of atrial mechanical behaviour.

Relations between movement of the atrioventricular ring and changes in left atrial and ventricular dimensions were studied by echocardiography and compared with apexcardiography and Doppler mitral flow velocity traces in 20 healthy controls and in patients with left ventricular hypertrophy (n = 28) or dilatation (n = 16). During left ventricular systole the atrioventricular ring, a structure common to ventricle and atrium, moved towards the ventricular apex, thus increasing left atrial volume. This action matched pulmonary venous return because it was in phase with the transverse left atrial dimension measured from aortic root to posterior left atrial wall. During early diastole, the mitral ring moved rapidly towards the atrium as transmitral flow accelerated. This requires a force directed from ventricle to atrium, likely to be the result of elastic recoil arising from compression of the ventricular myocardium or stretching of the atrial myocardium during ventricular systole. Two additional mechanisms of ventricular filling with atrial systole were recognised: (a) an increase in ventricular volume as the atrioventricular ring moved upwards and (b) transverse left ventricular expansion by pressure driven transmitral flow. The former is undetectable by Doppler from the apex; it accounted for 10% of ventricular filling in the healthy controls, but for significantly less in those with ventricular dilatation. In left ventricular hypertrophy, left ventricular filling was maintained by both mechanisms compensating for the reduced increase in volume early in diastole. Interactions between the atrium and ventricle are functionally important during ventricular systole, early diastole, and in atrial systole. They are not included in the traditional separation of atrial function into reservoir, conduit, and pump functions.

Atrial Function, Left↗
PubMed1990

Sequence requirements for proteolytic processing of glycoprotein B of human cytomegalovirus strain Towne.

Truncated versions of the human cytomegalovirus (CMV) strain Towne glycoprotein B (gB) gene were stably expressed in CHO cell lines. The calcium-specific ionophore A23187 inhibited proteolytic cleavage of C-terminal-truncated gB expressed by cell line 67.77. These inhibition studies also showed that the 93-kilodalton cleavage product most likely represents the N-terminal cleavage fragment of gB. The ionophore carboxyl cyanide m-chlorophenyl-hydrazone was used to show that proteolytic cleavage of gB did not occur in the endoplasmic reticulum. Two-dimensional polyacrylamide gel electrophoresis demonstrated that the N- and C-terminal cleavage products of gB remained associated by disulfide linkages after cleavage. Expression studies using constructs in which 80% or all of the N terminus was deleted demonstrated that the N terminus was required for secretion of the gB molecule. The amino acid sequence at the site of cleavage was shown to be critical for cleavage by a cellular protease. Our results indicate that an arginine-to-threonine change at either amino acid 457 or 460, a lysine-to-glutamine change at amino acid 459, or all three substitutions together block gB cleavage. The effect on proteolysis of the arginine-to-threonine amino acid change at residue 457 (position -4 relative to the cleavage site) demonstrated that a basic pair of amino acids at the endoproteolytic processing site is not the only requirement in cis for gB cleavage.

Amino Acid Sequence↗
PubMed1989

Left ventricular dysfunction in obstructive lung disease: an echocardiographic and angiographic study of cor pulmonale patients with decreased mitral E-F slope.

Twenty-nine patients with cor pulmonale were investigated by echocardiography and cardiac catheterisation in order to assess the significance of a reduced mitral E-F slope. Seven patients had coronary arterial disease and were therefore excluded from further analysis. Of the remaining 22 patients, 15 had a reduced mitral E-F slope but an otherwise normal mitral valve on echocardiography. They were found to have an increased left ventricular end-diastolic pressure measured at cardiac catheterisation when compared to the other seven patients with cor pulmonale and a normal E-F slope. The patients with a reduced E-F slope had an increased mean right ventricular internal dimension and interventricular septal thickness measured echocardiographically when compared to the patients with a normal E-F slope. Right ventricular dysfunction was suggested in these patients by an increased right ventricular end-diastolic pressure measured at cardiac catheterisation. We discuss possible mechanisms of left ventricular dysfunction and of intracardiac pressure transmission in cor pulmonale, and the implications of these mechanisms for effective management.

Aged↗