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Biomedical subjects

J J Hwang

Publications and source records attributed to J J Hwang.

At least 145 records · Page 8Linked to original sources
PubMed1993

The physiological effects of relaxin during pregnancy: studies in rats and pigs.

For 50 years after its discovery in 1926, there was a general lack of interest in relaxin among both reproductive biologists and clinicians. A key reason for this lack of interest was the lack of information concerning relaxin's physiological importance during pregnancy in any species. Research conducted since the early 1980s has established that the hormone relaxin is essential during pregnancy in at least two species--rats and pigs. Two vital roles for relaxin during pregnancy have been identified. Relaxin promotes growth and softening of the uterine cervix and thereby enables rapid and safe delivery in both rats and pigs. Relaxin also promotes growth and development of the mammary apparatus in both species. Interestingly, the major effects of relaxin on mammary growth and development are targeted on the nipple in the rat, whereas they are targeted on the glandular parenchyma in the pig. Relaxin-dependent growth of the nipple in rats is required for normal lactational performance. Although likely, it remains to be established that relaxin's profound effects upon mammary gland development in pigs are required for normal lactational performance. The fact that relaxin has effects upon cervical and mammary gland development during pregnancy in both rats and pigs encourages the view that relaxin may have similar effects during pregnancy in other species. Nevertheless, one must keep in mind that there is great diversity in the physiology of relaxin among species (reviewed by Sherwood 1988). This diversity includes not only relaxin's source, regulation of synthesis and secretion, and secretory profiles during pregnancy, but also its biological effects. It seems essentially certain that relaxin's effects during pregnancy differ among species. For example, transformation of the pubic joint cartilage to a flexible and elastic interpubic ligament occurs during pregnancy in several species, including guinea pigs, mice, and bats. This pelvic adaptation, which is nearly certainly relaxin dependent, does not occur in species such as rats and sheep. It is possible that relaxin may have little or no physiological significance during pregnancy in some species. Although considerable progress has been made toward an understanding of the physiological role(s) of relaxin in pregnant rats and pigs, many fundamental questions remain unanswered.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1993

Asbestos related pleural plaques in retired boiler room workers.

Occupational disease is often underestimated and only a few formal reports have been published in Taiwan. This study reports of a group of workers with asbestos-induced-disease, pleural plaque in Taiwan. Pleural plaque is a marker of exposure to asbestos. The disease was found in chest radiographs of five boiler room workers in a sugar refining factory. The chest radiographs of 248 current workers in that plant were reviewed, and none of them was found to have pleural plaques. The storage of asbestos and the long-time use of mixed asbestos cement for insulation of the inner wall of the stove and pipes were found in the factory. The authors believe that the pleural plaques might be resulted from occupational exposure to asbestos. It is suggested that the use of asbestos should be prohibited, step by step, and regular follow-up of the workers with an asbestos exposure history is required.

Aged↗
PubMed1992

Morphologic characterization and quantitative assessment of mitral regurgitation with ruptured chordae tendineae by transesophageal echocardiography.

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of morphologic characteristics and in the quantitative assessment of the severity of mitral regurgitation with ruptured chordae tendineae, 40 patients with ruptured chordae tendineae (group 1) and 20 patients with moderate or severe mitral regurgitation due to other causes (group 2) were studied. All echocardiograms were recorded before cardiac surgery. Cardiac catheterization was performed in 55 patients (92%). TEE showed greater sensitivity and negative predictive value than TTE (100 vs 65%, and 100 vs 56%, respectively; p < 0.005) in the diagnosis of ruptured chordae tendineae. Visualization of the ruptured chordae (termed snake-tongue sign) was highly sensitive and specific (93 and 95%, respectively) for establishing the diagnosis of ruptured chordae tendineae. The severity of mitral regurgitation in group 1 patients evaluated by TTE color flow mapping was underestimated by 2 grades in 1 patient and by 1 grade in 6 patients, and overestimated by 1 grade in 1 patient, compared with left ventriculography. In contrast, by TEE color flow mapping it was underestimated by 1 grade in 1 and overestimated by 1 grade in 1 patient. TEE color flow mapping showed better correlation with angiography than did TTE color flow mapping (r = 0.82 vs r = 0.49).

Adult↗
PubMed1992

Reappraisal by transesophageal echocardiography of the significance of left atrial thrombi in the prediction of systemic arterial embolization in rheumatic mitral valve disease.

Systemic arterial embolization imparts a significant risk of serious complications throughout the lives of patients with rheumatic heart disease. Left atrial (LA) thrombi have been thought to be the major source of emboli. A transesophageal echocardiography (TEE) study of 260 consecutive patients with rheumatic mitral valve disease was performed during a period of 24 months, with particular reference to understanding the association between LA thrombi and embolic complications. Of these patients, 155 had predominant mitral stenosis, 24 had significant mitral regurgitation, and the remaining 81 with xenograft mitral valve replacement developed valvular dysfunction (25 resulted in predominant mitral stenosis and 56 in significant mitral regurgitation). LA thrombi were detected in 38 patients (group A) and absent in 222 (group B). Group A patients had a higher frequency of recent (less than or equal to 1 week before TEE study) and remote (greater than 1 week before) embolization than did group B patients (recent: 26.3 vs 5.4% [p less than 0.001]; remote: 18.4 vs 5.0% [p less than 0.01]). The frequency of atrial fibrillation was also greater in group A patients (100 vs 74.3%; p less than 0.001). The exclusion of patients with significant mitral regurgitation and sinus rhythm had no effect on the association between LA thrombi and evidence of previous embolization. It is concluded that TEE is a convenient diagnostic modality that can be used to identify a subset of patients with rheumatic mitral valve disease at high risk for systemic embolization. Consequently, preventive anticoagulation for possible embolic complications should be more vigorously adhered to in patients with rheumatic mitral valve disease and LA thrombi.

Echocardiography↗
PubMed1992

Prospective study of blood culture during transesophageal echocardiography.

To ascertain the incidence and significance of bacteremia associated with transesophageal echocardiography (TEE), 132 consecutive patients (aged 17 to 73 years) free of apparent infection who were undergoing 135 transesophageal echocardiographic procedures from October 1990 to August 1991, were prospectively studied. For each procedure, two sets of blood cultures were obtained for culture 30 to 60 minutes before TEE, immediately after, and 180 to 240 minutes after the procedure. For each blood culture, 10 ml of venous blood was evenly inoculated into aerobic and anaerobic culture bottles and inoculated for 7 days using a radiometric system. A throat swab was obtained immediately before each procedure. Three of 270 preprocedure blood cultures were positive for Bacillus cereus, Staphylococcus simulans, and Peptostreptococcus species, respectively. No blood culture was positive in the immediate postprocedure period. Two of 270 late blood samples grew Staphylococcus epidermidis in the same patient. Nevertheless, the microorganisms isolated from blood cultures were different from those isolated from the throat swab. No patients had fever or evidence of infective endocarditis after TEE during the follow-up period. It is concluded that the incidence of TEE-related bacteremia is extremely low, and a general recommendation for antibiotic prophylaxis during TEE is not warranted.

Adolescent↗
PubMed1992

Effect of altered acid-base balance and of various agonists on levels of renal glutamate dehydrogenase mRNA.

Rat kidney contains 3.5-kb and 2.8-kb mRNAs that encode for glutamate dehydrogenase (GDH). The levels of both mRNAs are increased gradually after onset of chronic metabolic acidosis and reach a maximum induction of 2.5-fold after 7 days. In contrast, during recovery from chronic acidosis, the levels of the GDH mRNAs are returned to normal within 1 day. The development of an acute metabolic acidosis causes a more rapid induction of GDH mRNA. This increase occurs after a 7-h lag and plateaus after 18 h at a level that is threefold greater than normal. A very similar profile was observed after the transfer of LLC-PK-F+ cells from normal medium to an acidic medium containing 10 mM bicarbonate and adjusted to pH 6.9. However, the transfer of cells from acidic to normal medium caused an immediate and rapid [half-life (t) = 1 h] decrease in GDH mRNA. The apparent half-lives of GDH mRNA were measured by treating cells grown in normal (t = 4 h) and acidic media (t = 12 h) with actinomycin D. Thus, increased stability may account for the induction of GDH mRNA that occurs during growth in response to acidosis. The levels of GDH mRNA are independently affected by changes in medium pH or bicarbonate concentration. The levels of GDH mRNA are also increased by treating cells with adenosine 3',5'-cyclic monophosphate, epinephrine, triiodothyronine, or retinoic acid, whereas treatment with angiotensin II, vasopressin, phorbol 12-myristate 13-acetate, or cycloheximide did not produce an increase. The inductive effect of dexamethasone, which is observed in vivo, is not reproduced in the LLC-PK-F+ cells.

Acid-Base Equilibrium↗
PubMed1992

Monoclonal antibodies specific for rat relaxin. VI. Passive immunization with monoclonal antibodies throughout the second half of pregnancy disrupts histological changes associated with cervical softening at parturition in rats.

Relaxin, which is secreted by the corpora lutea throughout the second half of rat pregnancy, promotes the growth and softening of the cervix. The mechanisms at both the cellular and molecular levels by which relaxin brings about these effects remain to be determined. The present study examined the influence of endogenous relaxin on the histological changes associated with cervical softening. A monoclonal antibody for rat relaxin, designated MCA1, was injected iv daily on days 12-22 of gestation. Cervices were removed on day 22, fixed in 10% buffered formalin, embedded in paraffin, and processed for histological staining. Tissue sections (5 microns thick) were stained with Gomori's trichrome stain (collagen), Orcein stain (elastin), or periodic acid-Schiff (polysaccharide). Qualitative and quantitative analyses identified several histological parameters in MCA1-treated rats that differed markedly from those in control rats. Cervices obtained from MCA1-treated rats contained collagen fiber bundles with greater compactness; elastin fibers with greater density, length and interdigitation; arteries with smaller cross-sectional areas; and luminal involutions with smaller areas than controls. The cervices of MCA1-treated rats appeared to contain fewer vacuolated epithelial cells, which secrete polysaccharide-rich material, than did cervices obtained from controls. It seems plausible that most, if not all, of these relaxin-induced modifications of the histological characteristics of the cervix facilitate birth.

Animals↗
PubMed1992

Evidence for a dual source of relaxin in the pregnant rat: immunolocalization in the corpora lutea and endometrium.

Uterine tissue was collected from intact pregnant rats on days 4, 10-15, 18, and 22 of pregnancy and day 2 postpartum and from rats on day 22 of pregnancy after ovariectomy (day 9) and progesterone-estrogen treatment. Placental, cervical, mammary, and pituitary tissues were collected from intact pregnant rats on day 22. Ovarian tissue was collected from intact pregnant rats on days 15, 20, and 22. These tissues were evaluated for relaxin immunostaining at the light microscope level using an antiserum to purified rat relaxin and the avidin biotin immunostaining technique. Since the corpus luteum is the major source of relaxin in the rat, this tissue was used as a positive control. Relaxin immunostaining in the corpus luteum was observed in a discrete region of the cytoplasm. This pattern of staining corresponded with the discrete clustering of relaxin-containing secretory granules found in the rat luteal cells. Relaxin was not observed in the day 22 placenta, cervix, mammary gland, pituitary gland, or day 4-13 pregnant uterus. Relaxin immunostaining was detected in endometrial epithelial cells on days 14-22 of pregnancy and day 2 postpartum. Relaxin immunostaining was more evident at implantation sites than between implantation sites. Antimesometrial epithelial cells at implantation sites contained relaxin immunostaining. The mesometrial surface, which consists of the placenta and decidualized endometrium, did not contain relaxin immunostaining. Relaxin immunostaining was also present in the endometrial epithelial cells of the day 22 pregnant rats that had been ovariectomized on day 9 and given subsequent replacement therapy with ovarian steroids. The presence of relaxin immunostaining in the ovariectomized rat indicates the endometrium is not sequestering relaxin secreted from the corpus luteum. These data provide evidence that the pregnant rat endometrium is a source of relaxin in addition to the corpus luteum. The appearance of relaxin in endometrial epithelial cells after implantation and its prominence at implantation sites may indicate that locally secreted conceptus factors stimulate endometrial relaxin synthesis.

Animals↗
PubMed1992

Ultrasonography of chest diseases: analysis of 154 cases.

Sonographic characteristics of various chest diseases in 154 cases were analysed according to margin of the lesion, internal echogenecity, posterior echo enhancement, air bronchogram etc. We intended to present the basic sonographic patterns of common chest diseases. The study included 10 normal cases, 10 cases with lung abscesses, 31 cases of pneumonia, 24 cases of tumors, 11 cases of obstructive atelectasis, 8 cases of pleuropericarcadial effusions, 10 cases of minimal effusions, 6 cases with pleural thickening, 32 cases of massive pleural effusion with simple compression atelectasis and 12 cases of pneumonia with parapneumonic effusion. Sonographically, normal lung showed hyperechoic zone beneath the chest wall. Identification of arc or ring-shaped wall favored lung abscess. Air bronchogram could only be found in pneumonia. Mass showed various internal echogenecity. The internal echogenecity in obstructive atelectasis was very homogeneous which could not be found in tumor. Pleural thickening showed linear hyperechogenecity beneath the chest wall. In minimal effusion, the line of the diaphragm could be easily identified. Pleuropericardial effusion could be easily diagnosed by chest sonography. The line of the pericarcadium could be clearly identified. The internal echogenecity of massive effusion were various. The internal echogenecity of simple compression atelectasis showed very homogeneous hyperdense internal echogenecity. The internal echogenecity of lung parenchyma in pneumonia with parapneumonic effusion was similar to that of pneumonia. Obstructive atelectasis, mass, consolidation and encapsulated effusion could be differentiated by chest sonography without much difficulty. Sonography could aid chest radiography by giving more morphologic information and was cheaper than computed tomography.

Adult↗
PubMed1992

Flow cytometric DNA analysis of pleural effusions.

A total of 71 cases of pleural effusion in patients with and without cancer were analyzed by conventional cytology and flow cytometry (FCM) in order to detect cells with an abnormal DNA content (aneuploidy). For cytologic examination, the samples were prepared using standard techniques. Sample for FCM analysis were centrifuged and exposed to hypotonic solution containing detergent and propidium iodide. Thirty-eight patients had pleural effusion due to benign disease, whilst 33 patients had primary lung cancer. All 38 patients with benign pleural effusions showed FCM diploidy. There were 17 aneuploidy (52%) and 16 diploidy (48%) in the 33 patients with lung cancer by FCM analysis. Four of these 33 effusions were cytologically negative, however, FCM showed aneuploidy in 2 of these 4 patients. Based on these results, FCM analysis combined with conventional cytopathology yielded 100% specificity, 94% sensitivity and 100% predictive value of positive result. There were no false-positive results but 2 false-negative results. These findings suggest that FCM is a rapid and useful technique in the analysis of pleural effusion and can be a very useful adjunct to conventional cytopathology.

DNA↗
PubMed1992

Streptococcus bovis endocarditis associated with colonic adenocarcinoma: report of a case.

Streptococcus bovis (S. bovis) endocarditis has been increasing over recent decades, especially among the senile population. A 74-year-old man presented with intermittent fever for two months. He had a past history of aortic dissection and underwent a Bentall operation one year before admission. A Janeway lesion was noted on his right hand and six blood cultures grew S. bovis. He was treated with penicillin-G, 3 microU intravenously, every six hours, and became afebrile three days later. A colonofiberoscopy was carried out despite the absence of any gastrointestinal symptoms, and a 2 x 2 cm mass was found at the cecum, with pathologic proof of adenocarcinoma. The patient died from a massive intracranial hemorrhage on the 23rd hospital day. Review of the literature revealed an intimate association between S. bovis bacteremia (or endocarditis) and underlying colonic neoplasia. Failure to be aware of the possible consequences of this combination may lead to detrimental patient prognosis. We strongly advise that every patient presenting with bacteremia or endocarditis due to this organism, even if they are free from gastrointestinal symptoms, should undergo a thorough lower gastrointestinal investigation to rule out colonic neoplasia.

Adenocarcinoma↗
PubMed1992

Application of staining of nucleolar organizer regions in cytological smears of the bronchus.

An argyrophil technique for the staining nucleolar organizer regions (AgNOR) was applied to cytological preparations obtained from bronchoscopic brushing materials. The number of AgNOR has been thought to be related to cellular activation. To differentiate malignant cells from non-malignant atypical cells, this study was carried out in 20 cases of adenocarcinoma of the lung (mean AgNOR: 18.34), 12 cases of pulmonary inflammatory diseases (mean AgNOR: 6.54) and 10 normal bronchial epithelial specimens for control (mean AgNOR: 2.07). On the basis of AgNOR number, we could differentiate between the three groups. The differences observed were statistically highly significant (p less than 0.0001). Moreover, the nucleolar organizer regions (NOR) in cancer cells were found the more irregularly distributed and more variable in sized than those in atypical and normal bronchial columnar cells. We suggest that the AgNOR technique will find increasing application as a complementary test in diagnostic cytopathology.

Adenocarcinoma↗
PubMed1991

Mechanism of altered renal glutaminase gene expression in response to chronic acidosis.

Increased rat renal ammoniagenesis is sustained during chronic metabolic acidosis by the cell-specific induction of the regulatory enzymes of glutamine catabolism and of gluconeogenesis. A glutaminase-specific cDNA hybridizes to 6.0- and 3.4-kb mRNAs that are contained in total or poly(A)+ RNA isolated from rat kidney. When translated in a rabbit reticulocyte lysate, each of the fractionated mRNAs produces the 72-kDa precursor of the mitochondrial glutaminase. The levels of both mRNAs are increased 5-fold within 1 day following onset of chronic acidosis and reach a maximum (8-fold) after 5 days. During recovery from chronic acidosis, the levels of the glutaminase mRNAs are returned to normal within 1 day. The observed changes in mRNA levels correlate with equivalent changes in the relative levels of translatable glutaminase mRNA. Nuclear run-on assays indicate that the rate of transcription of the renal phosphoenolpyruvate carboxykinase gene is increased and decreased in response to onset and recovery from chronic acidosis, respectively. In contrast, the rates of transcription of the glutaminase and beta-actin genes are unaffected by alterations in acid-base balance. Thus, the increase in renal glutaminase activity during chronic acidosis results from an equivalent increase in the levels of total and translatable glutaminase mRNAs which apparently results from an increased stability of the glutaminase mRNA.

Acidosis↗
PubMed1991

Effect of acute alterations in acid-base balance on rat renal glutaminase and phosphoenolpyruvate carboxykinase gene expression.

During chronic acidosis, the levels of the rat renal mRNAs that encode the mitochondrial glutaminase (GA) and cytosolic phosphoenolpyruvate carboxykinase (PCK) are increased 6-fold. Following acute recovery of chronic acidosis, the levels of the two mRNAs are rapidly and coordinately decreased, returning to normal within 13-17 h. In contrast, the increases in GA and PCK mRNAs during acute onset of acidosis occur with very different kinetics. The increase in PCK mRNA occurs rapidly and reaches a maximum within 7 h, whereas the GA mRNA is increased after a 4-7-h lag and then plateaus at 14-17 h. Treatment with dexamethasone or with cAMP analogs significantly increases the level of renal PCK mRNA but has no effect on the level of GA mRNA. Nuclear run-on experiments indicate that the acute induction of PCK mRNA is primarily due to an increased rate of transcription. However, transcription of GA mRNA is unaffected by acute acidosis. Therefore, the changes in the two mRNAs are temporally coordinated but occur through different mechanisms. Furthermore, the inductive effects of acidosis are not mediated solely through glucocorticoid or cAMP regulatory elements.

Acidosis↗
PubMed1991

Interventricular septum rupture due to falling from a height.

Non-penetrating traumatic interventricular septal rupture of the heart is rare. This lesion can result from blunt injuries, either immediate or delayed, but has never been reported from blunt chest trauma secondary to falling from height. Surgical repair can usually be done as an elective procedure with good results. However, with some patients early repair is necessary as a lifesaving measure. We report on a 15-year-old patient admitted after falling from the fourth floor with multiple bone fractures and blood pressure of 80/0. He soon required mechanical ventilation, but a heart murmur was only detected after some hours. On the fifth day a non-penetrating traumatic interventricular septal rupture became apparent, which was proved by echocardiography and Swan-Ganz catheterization. The patient underwent successful repair of the interventricular septal defect on the 13th day following injury. Two weeks later surgery for his bone fractures was carried out, after which the patient could be discharged uneventfully.

Accidental Falls↗
PubMed1991

Monoclonal antibodies specific for rat relaxin. V. Passive immunization with monoclonal antibodies throughout the second half of pregnancy disrupts development of the mammary apparatus and, hence, lactational performance in rats.

There were two related objectives to this study. The first was to determine the influence of relaxin on development of the mammary apparatus (nipples and glands) during the second half of pregnancy. The second was to determine whether the relaxin-dependent development of the mammary apparatus was required for normal postpartum lactational performance. Both objectives were accomplished by neutralizing endogenous relaxin throughout the second half of pregnancy with a monoclonal antibody specific for rat relaxin (MCA1). MCA1 was administered iv to rats daily from days 12-22 of pregnancy. On day 22 the morphology of the mammary apparatus of MCA1-treated rats differed from that of controls; nipples were dramatically smaller, collagen fibers had significantly greater mean density and consistency, and elastin fibers had greater mean density, length, and interdigitation. In addition, the mean number of alveoli surrounding lactiferous ducts was significantly smaller in MCA1-treated rats than in controls. There were no differences between MCA1-treated rats and controls in the mean thickness of connective tissue surrounding ducts, the height or density of luminal cells lining lactiferous ducts, or the sizes of either adipocytes or arteries. To examine lactational performance, MCA1-treated and control rats were cesarean sectioned between 2100-2400 h on day 22 of pregnancy and given foster pups born of untreated intact donors. Although both MCA1-treated rats and control rats exhibited a high incidence of maternal behavior after cesarean delivery, mean pup weight and incidence of live pups declined markedly during days 1-5 of fosterage in MCA1-treated rats compared to controls. Furthermore, unlike controls, there was no observable postpartum nipple development in MCA1-treated rats by day 5 of fosterage. Mammary glands obtained from MCA1-treated rats on day 5 of fosterage had markedly lower mean weight than controls. This study demonstrates that passive immunization of endogenous relaxin throughout the second half of pregnancy disrupts development of the nipples and mammary glands in the rat. Moreover, it establishes that relaxin's effects on the development of the mammary apparatus during pregnancy are essential for growth and survival of the young during lactation.

Animals↗
PubMed1991

Atypical myxoma.

We report the case of a 38-year-old woman with a large thin-walled cystic mass (6 x 5 x 4.5 cm) filled with arterial blood in the right atrium. The cystic mass with blood content was clearly delineated by transesophageal cross-sectional echocardiography and magnetic resonance imaging of the heart. At operation, a silver-whitish, smooth surfaced cystic mass was found attached to the free wall of the right atrium between the superior vena cava and the right atrial appendage with a broad base. Microscopically, the wall of the cyst was composed of stellate mesenchymal cells embedded within a myxoid matrix which was proved by alcian blue stain. To our knowledge, this type of cardiac myxoma has not been previously reported.

Adult↗