Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 433 records · Page 24Linked to original sources

PubMed1991

Limb salvage of infected diabetic foot ulcers with microsurgical free-muscle transfer.

This study was comprised of 9 diabetic patients with 10 infected foot ulcers, including osteomyelitis in 4 limbs and gangrene in 3 limbs. Adequate debridement of these complicated wounds inevitably resulted in exposure of bones or tendons. All defects were successfully reconstructed with free gracilis muscle flaps covered with split-thickness skin grafts. No recurrence of ulcer or infection was noted in the muscle-transplanted area during the follow-up period. Laser Doppler perfusion monitor measurement showed that the perfusion unit of the denervated free muscle flap increased to a peak at the second week after transplantation; the neovascularization of the grafted skin, the progressive decrease of the muscle swelling, and the decreased interstitial pressure may be the main contributing factors. The perfusion unit of the muscle flap reached equilibrium with the surrounding tissue at about 8 weeks after microsurgical transfer. Lower extremity amputation is a major health problem in the diabetic population. The microvascular free-muscle transfer was proved to play an effective and important role in limb salvage in diabetic patients with infected foot ulcers. The gracilis muscle flap was recommended due to its lack of bulkiness and minimal donor site deformity.

Aged↗

PubMed1991

Comparison of indium-111 scintigraphy and colonoscopy with histologic study in children for evaluation of colonic chronic inflammatory bowel disease.

Indium-111 leukocyte scanning and colonoscopy were performed in 19 children and adolescents with chronic inflammatory bowel disease to study the correlation of evaluation between these two diagnostic modalities in comparison to histologic study for colonic disease. Seven patients had ulcerative colitis, 10 had Crohn's disease, and two patients had no specific diagnosis after evaluation. The sensitivity of indium-111 scan was 18%, specificity was 62.5%, and accuracy for diagnosing colonic disease was only 37%. In comparison, sensitivity and specificity for colonoscopy were 100 and 57%, respectively. Furthermore, accuracy with colonoscopy was 84%. Our data suggest that the usefulness of scans is limited to patients in whom standard diagnostic procedures are contraindicated. In addition, it is essential to confirm the visual diagnostic impression on colonoscopy with histologic study.

Adolescent↗

PubMed1991

Mast cell degranulation and elastolysis in the early stage of striae distensae.

The lesions of nine patients with early striae distensae (SD) during puberty were examined by light and electron microscopy. Specific changes were seen in very early stage SD, and in clinically uninvolved skin 0.5 to 3 cm remote from the edge of the long axis of the SD lesions. Sequential changes of elastolysis accompanied by mast cell degranulation appeared first, followed by an influx of activated macrophages that enveloped fragmented elastic fibers. The relationships among elastic fibers, mast cells, and macrophages seen in the present work suggest their critical roles in the process of SD formation, especially in the early stage. Our results also indicate that the elastic fiber is the primary target of the pathological process, and the abnormalities extend as far as 3 cm beyond the lesion into normal skin.

Adolescent↗

PubMed1991

Structural, molecular, and genetic analysis of the kilA operon of broad-host-range plasmid RK2.

The kil loci (kilA, kilB, kilC, and kilE) of incompatibility group P (IncP), broad-host-range plasmid RK2 were originally detected by their potential lethality to Escherichia coli host cells. Expression of the kil determinants is controlled by different combinations of kor functions (korA, korB, korC, and korE). This system of regulated genes, known as the kil-kor regulon, includes trfA, which encodes the RK2 replication initiator. The functions of the kil loci are unknown, but their coregulation with an essential replication function suggests that they have a role in the maintenance or host range of RK2. In this study, we have determined the nucleotide sequence of a 3-kb segment of RK2 that encodes the entire kilA locus. The region encodes three genes, designated klaA, klaB, and klaC. The phage T7 RNA polymerase-dependent expression system was use to identify three polypeptide products. The estimated masses of klaA and klaB products were in reasonable agreement with the calculated molecular masses of 28,407 and 42,156 Da, respectively. The klaC product is calculated to be 32,380 Da, but the observed polypeptide exhibited an apparent mass of 28 kDa on sodium dodecyl sulfate-polyacrylamide gels. Mutants of klaC were used to confirm that initiation of translation of the observed product occurs at the first ATG in the klaC open reading frame. Hydrophobicity analysis indicated that the KlaA and KlaB polypeptides are likely to be soluble, whereas the KlaC polypeptide was predicted to have four potential membrane-spanning domains. The only recognizable promoter sequences in the kilA region were those of the kilA promoter located upstream of klaA and the promoter for the korA-korB operon located just downstream of a rho-independent terminatorlike sequence following klaC. The transcriptional start sites for these promoters were determined by primer extension. Using isogenic sets of plasmids with nonpolar mutations, we found that klaA, klaB, and klaC are each able to express a host-lethal (Kil+) phenotype in the absence of kor functions. Inactivation of the kilA promoter causes loss of the lethal phenotype, demonstrating that all three genes are expressed from the kilA promoter as a multicistronic operon. We investigated two other phenotypes that have been mapped to the kilA region of RK2 or the closely related IncP plasmids RP1 and RP4: inhibition of conjugal transfer of IncW plasmids (fwB) and resistance to potassium tellurite. The cloned kilA operon was found to express both phenotypes, even in the presence of korA and korB, whose functions are known to regulate the kilA promoter. In addition, mutant and complementation analyses showed that the kilA promoter and the products of all three kla genes are necessary for expression of both phenotypes. Therefore, host lethality, fertility inhibition, and tellurite resistance are all properties of the kilA operon. We discuss the possible role of the kilA operon for RK2.

Amino Acid Sequence↗

PubMed1991

Renal angiomyolipoma: experience of 23 patients.

We reported 29 kidneys with angiomyolipoma in 23 patients (14 women and 9 men). One of these cases was associated with tuberous sclerosis. Their age ranged from 20 to 82 years (mean 48.9). Six patients had bilateral renal involvement and 7 had multiple lesions in one kidney. Synchronous renal tumors were noted in three patients. One patient was associated with renal cell carcinoma, and the other two patients with transitional cell carcinoma. Nineteen tumors in 16 patients were larger than 4 cm. Among them 93.8% (15/16 patients) were symptomatic and tumor hemorrhage was found in 57.9% (11/19 kidneys). Of these patients, 17 renal units underwent surgical intervention (including 8 total nephrectomy, 7 partial nephrectomy and 2 enucleation of tumor). Preoperative diagnosis was made in 82.4% (14/17) with combined imaging of sonogram and CT scan. One patient received embolization only. There were two mortalities: one patient with tumor rupture who received emergent nephrectomy but died of irreversible hypovolemic shock, and the other with tuberous sclerosis and pulmonary fibrosis who received embolization for spontaneous rupture of tumor but expired due to respiratory failure. Among nine patients receiving renal preserving operation, the post-operative effective renal plasma flow of the affected kidneys ranged from 96 to 184 ml/min (mean 131.7 ml/min). There was no evidence of recurrence during a mean followup of 2.6 years. Eight asymptomatic patients with 9 renal masses had incidental angiomyolipoma and did not undergo exploration. We did not note any progression of the lesions in the cases under observation for a mean followup of 2.6 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Trichotillomania: a clinical study of 36 patients.

To understand the clinical characteristics of trichotillomania, 36 patients were investigated at the psychocutaneous special clinic from February 1982 to October 1990. There were 16 males and 20 females. The most prominent age was found in a group of 23 (63.9%) elementary school children, and in regards to the age of disease onset, 35 (97.2%) of our patients were under the age of 18. A 30-year-old woman with schizophrenia and a 6-year-old boy with mental retardation were noted in our study; the remaining 34 patients were generally well without signs of mental illness except for the recurrent failure to resist impulses to pull out their own hair. The common life events precipitating stress were academic problems and parent-child conflicts. The duration of follow-up was for at least 6 months. The habit of hair plucking was easily corrected if the duration of the disease was less than 6 months. Usually these patients had a satisfactory regrowth of hair within 1-3 months after our explanation and reassurance. In contrast, the patients with a hair loss of more than half a year were not easy to approach, and needed psychiatric treatment.

Adolescent↗

PubMed1991

Hormonal screening in impotent patients.

Of a total 260 impotent patients entered in a hormonal study, serum testosterone, prolactin and hormonal abnormalities were detected in 30 (11.5%) patients (18 with hypotestosteronemia and 12 with hyperprolactinemia). The 18 cases of hypotestosteronemia included: 8 cases of hypergonadotropic hypogonadism due to klinefelter's syndrome (1), orchitis (2), chronic alcoholism (1), and idiopathic primary gonadal failure (4) and 10 cases etiologically unknown hypotestosteronemia. Nine of the 18 patients also displayed other organic etiologies (6 vasculogenic and 3 diabetic impotence). After replacement of testosterone propionate by intramuscular injection, the improvement in impotence was significant in 12 patients (excellent in 1, good in 11) and insignificant in 6 (poor in 3, no response in 3). The positive response rate was 89% (8/9) for sole hypotestosteronemia and 44% (4/9) for hypotestosteronemia accompanied by other organic causes of impotence. In the 12 patients with hyperprolactinemia, 4 had prolactinomas. Of these, 3 were treated by surgery and 1 with bromocriptine. Three (excellent in 2, good in 1) of the 4 showed a positive erection response afterwards, but the other patient's response was poor because of postoperative residual tumor. Two patients had drug-induced hyperprolactinemia (haloperidol and methyldopa) and for one, impotence was improved after withdrawal of haloperidol. However, the other responded poorly due to vasculogenic impotence. Six patients with hyperprolactinemia of unknown etiology (2 accompanied by vasculogenic impotence, 2 by diabetic impotence and 2 by sole hyperprolactinemia) were treated with bromocriptine and improvement was noted in 3. The positive response rate was 71.4% (5/7) for sole hyperprolactinemia and 40% (2/5) for hyperprolactinemia accompanied by other organic causes of impotence. Good results were achieved in prolactinoma, sole hyperprolactinemia and hypotestosteronemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Alterations in water content of the stratum corneum following long-term topical corticosteroids.

The water content of the stratum corneum (SC), profilaggrin/filaggrin (PF/FG) and stratum corneum neutral lipids were examined in 23 patients following use of long-term topical corticosteroids (TCS). All patients showed the rebound phenomenon after stopping TCS. Biopsy specimens were taken from the atrophic skin and from the peripheral normal skin of patients. The histopathological examination showed a thinning of the horny layer and the epidermis, along with a decrease in or the absence of the granular layer in the patient's lesional skin. Oil red 0 staining for SC neutral lipids revealed that the intensity of the lipid staining was markedly reduced. Ultrastructural observation also revealed an obvious decrease in both the formation of keratohyalin granules and in the membrane-coating granules of steroid-treated skin. Furthermore, indirect immunofluorescence for PF/FG demonstrated markedly reduced immunofluorescence. In agreement with the above results, the mean water content of the SC in lesional skin was also significantly decreased when compared with that of controls. Since the water content of SC is suggested to be dependent on both the keratohyalin-derived natural moisturizing agents of the SC and the SC intercellular lipids, the present results suggest that the diminution in SC lipids and PF/FG in steroid-treated skin may play an important role in the low hydration state of the SC and the clinical manifestations of scaling and dryness of the skin in patients suffering from the rebound phenomenon after stopping TCS.

Administration, Topical↗

PubMed1991

[Necrolytic migratory erythema as the first manifestation of glucagonoma].

A 49-year-old woman suffered from recurrent episodes of necrolytic migratory erythema over the lower legs, lower abdomen, and buttocks for more than two years. Stomatitis, glossitis and vaginitis were the accompanying symptoms and signs during each episode. The result of skin biopsy revealed superficial necrosis in the upper half of the epidermis. Laboratory examinations revealed mild glucose intolerance and hypoaminoacidemia. Fasting plasma glucagon level measured by radioimmunoassay was 890 pg/mL. Oral glucose loading test showed a paradoxical increase in plasma glucagon level up to 1,500 pg/mL. Abdominal echo, computerized axial tomography, and celiac angiography demonstrated a hypervascular tumor, 4 cm in diameters, located at the pancreatic head. Glucagonoma syndrome was confirmed and diagnosed. The patient underwent surgical resection of the tumor mass. Necrolytic migratory erythema disappeared thereafter, and the plasma glucagon level declined to 120 pg/mL. Histologically, the tumor revealed an islet cell carcinoma composed of moderately uniform cells with a few mitosis, arranged in cords and nests. Abundant characteristic secretory granules of the pancreatic A cell were found within the tumor cells by electron microscopic examination.

Erythema↗

PubMed1991

Glomerular diseases in human renal allograft.

A total of 64 renal graft biopsies performed on 44 transplant patients from among 116 transplants (12 from living donors, 104 from cadavers) were analyzed during the period from July 1983 to December 1990. The frequency of allograft glomerular disease was 22.7% (10/44). Membranous glomerulonephritis (MGN) was detected in five patients; focal segmental glomerulosclerosis (FSGS), in two; transplant glomerulopathy, in two; and IgA nephropathy, in one. Nephrotic syndrome occurred in nine of the ten patients. Progressive deterioration of graft function developed in four patients associated with chronic rejection, and two of them later lost the graft. The remaining six patients had no chronic rejection and retained a stable renal condition with one exception, a patient who suffered from acute total occlusion of the right internal iliac artery and who eventually lost the graft. It is concluded that MGN is the most common allograft glomerular disease, but the outcome of the graft is probably related to the coexistent chronic rejection.

Adult↗

PubMed1991

Prenatal diagnosis of intracardiac rhabdomyoma: a case report.

We report on a case of intracardiac rhabdomyoma diagnosed prenatally from two-dimensional echocardiograms. The tumor was diagnosed by intrauterine echocardiography at the 38th week of gestation. Autopsy proved that the intracardiac tumor was a rhabdomyoma. Tuberous sclerosis spots in the brain tissue were also found.

Adult↗

PubMed1991

Clinical and hemodynamic results after Fontan operation.

Twenty-six patients, ranging in age from 2 to 14 years (mean, 6 years and 8 months), with tricuspid atresia or other complex cyanotic cardiac diseases underwent a modified Fontan operation between 1980 and 1990. In 13 patients, palliative operations had been previously performed. There were 7 mortalities within 1 month after the operation. Seventeen of the 19 survivors were followed up for 5-122 months (mean, 27) with no late deaths. Fifteen patients were in the New York Heart Association functional class 1. Two patients required reoperations at 2 and 57 months postoperatively: the former for atrio-ventricular valvular regurgitation, and the latter for late-developing conduit obstruction and residual atrial right to left shunting. Fourteen patients underwent cardiac catheterization after 1-57 months (mean, 9.8) postoperatively. Two patients had a residual right to left shunt at the atrial level, while the oxygen saturation in the remaining 12 patients was above 90%. Thus, the modified Fontan operation offers an alternate surgical approach for patients with complex congenital heart disease for whom no other palliative procedure can be expected to obtain significant improvement. It can be performed with good clinical and hemodynamic results in selected patients.

Adolescent↗

PubMed1991

Endothelium-dependent production of prostacyclin in human internal mammary artery.

The internal mammary artery (IMA) has become the conduit of choice in coronary artery bypass surgery because of superior long-term patency. It had been shown that IMA graft could release prostacyclin. Prostacyclin is a potent vasodilator and also can inhibit platelet aggregation. To determine the role of human IMA endothelium in production of prostacyclin, we tested the reactivity of segments of human IMA to hypoxia in vitro. Human IMAs were harvested during coronary artery bypass surgery. Prostacyclin was measured from fluid in the organ baths by radioimmunoassay of its major hydrolytic product 6-keto-prostaglandin F1 alpha. Rings (4 mm in length) of IMA, with and without endothelium, were suspended in organ baths containing physiologic salt solution. Rings were contracted with norepinephrine, and exposed to hypoxia (pO2 35 +/- 5 mmHg) for 15 minutes then reoxygenated. In segments with endothelium, hypoxia induced a transient relaxation followed by contraction. The transient relaxation was associated with a significantly increased production of 6-keto-prostaglandin-F1 alpha (from 34.1 +/- 2.7 pg/ml prehypoxia to 51.6 +/- 6.7 pg/ml during hypoxia, mean +/- SEM, p less than 0.05). This transient relaxation was blocked by indomethacin but not by NG-monomethyl-L-arginine (L-NMMA) and free radical scavengers (superoxide dismutase, catalase and deferoxamine). However, in segments without endothelium, the prehypoxia (14.7 +/- 0.9) and during hypoxia (15.5 +/- 1.4) level of 6-keto-prostaglandin F1 alpha were not increased and were significantly lower than those with endothelium. This study demonstrated that endothelium of IMA grafts could release prostacyclin either in a basal condition or upon stimulation of hypoxia. This ability possibly contributes to its long-term patency.

Cell Hypoxia↗

PubMed1991

Adenoma of type 2 pneumocytes with oncocytic features.

An adenoma of type 2 pneumocytes in the periphery of the left lung was an incidental finding at the autopsy of a 28-year-old woman. Light microscopy revealed a predominantly papillary growth with oncocytic features. Ultrastructurally, multilaminated bodies and many mitochondria were found in the tumor cells and tubular myelin in the extracellular spaces. Immunohistochemistry revealed surfactant apoprotein in tumor cells and extracellularly.

Adenoma↗

PubMed1991

Renal oncocytoma: report of two cases and review of literature.

Renal oncocytoma was previously reported as a benign tumor arising from proximal tubular epithelial cells, but malignant potential with local invasion and distant metastasis has been emphasized in recent literature. It is difficult to differentiate it from renal cell carcinoma, but four typical angiographical signs may give suggestive evidence of the tumor. Radical nephrectomy with lymphadenectomy may be the choice of treatment, except in solitary kidney, bilateral tumors, or contralateral renal cell carcinoma. We report two female patients who were found incidentally to have renal tumors during a survey of right upper quadrant pain. Typical angiographic signs were found incidentally to have renal tumors during a survey of right upper quadrant pain. Typical angiographic signs were found in one patient, and atypical signs in the other. Three and eight years after radical nephrectomy with para-aortic lymphadenectomy, there has been no evidence of local recurrence or distant metastasis.

Adenoma↗

PubMed1991

Primary retroperitoneal sarcomas--a report of 16 cases.

From November 1982 to August 1990, 16 patients with primary retroperitoneal sarcoma were treated in our hospital. The most frequent types of tumor were liposarcoma (6), malignant fibrous histiocytoma (3). The commonest clinical findings were palpable abdominal mass (14/16). In management of these patients; nine patients underwent complete resection of the tumor; three patients underwent partial resection of the tumor and four patients underwent biopsy only. The histology of tumor appeared to have prognostic significance. Patients suffering from liposarcoma (3/5) and malignant fibrous histiocytoma (1/2) survived the longest. With a mean follow up of 25.0 months, the three year overall survival rate of complete resection group was 50 per cent. No patients with partial resection and biopsy only group survive three years and the total three-years overall survival rate was 29%. The mean survival for patients after adjuvant chemotherapy and/or radiotherapy was similar to that after a radical operation alone. The prognosis of primary retroperitoneal sarcoma is grave and complete resection of the tumor as initial treatment seems to provide the only chance of cure for these patients.

Adolescent↗

PubMed1990

Structural requirements of ATP for activation of basal and atrial natriuretic factor-stimulated guanylate cyclase in rat lung membranes.

ATP has been reported to increase basal and atrial natriuretic factor (ANF)-stimulated guanylate cyclase activity. The structural features of ATP involved in the activation of guanylate cyclase were examined by employing a variety of ATP analogs with modification either at the phosphate chain or at the ribose moiety. Among the natural adenine nucleotides, ATP and ADP were able to increase both basal and ANF-stimulated guanylate cyclase activities in rat lung membranes. AMP had no effect. ATP was more effective than AMPPCP (the non-hydrolyzable analog of ATP), and ADP was more effective than ADP beta S and AMPCP (the hydrolysis-resistant analogs of ADP) to increase basal and ANF-stimulated guanylate cyclase activities. Removal of the oxygen atom from the ribose moiety of ATP or ADP significantly reduced their potency. Thus, the length of the phosphate chain and the hydroxyl groups at the ribose moiety are both determinants for nucleotide mediated guanylate cyclase activation.

Adenosine Diphosphate↗

PubMed1990

A simple method to create carotid endothelial laceration and acute platelet thrombus in vivo in guinea-pig.

A simple method, named 'clamp method', was developed to create carotid endothelial laceration and produce acute platelet thrombus in vivo in guinea-pig. This method used a hemostatic forceps to clamp common carotid artery of anesthetized guinea-pig at a tangent angle. Our study included two parts. The Part one demonstrated the procedures and effects of the 'clamp method': sixteen guinea-pigs were divided equally into control and heparin-treated groups. These two groups received the same clamping procedures except that the heparin-treated group was administrated with heparin (5,000U/kg) intravenously before clamping. One hour after the clamping, carotid arteries were resected and observed under scanning electron microscopy. The results showed that large carotid mural thrombi were formed in the control group with a mean surface area of 1.75 +/- 0.63 mm2 (M +/- SD, n = 8). In the heparin-treated group, the thrombus formation was prevented and linear endothelial lacerations were seen clearly. The Part two of our study identified the histologic nature of the thrombus produced by the 'clamp method': eight guinea-pigs received same procedures as that of control group in the Part one except that the carotid arteries were resected 5 min after performing the clamping. Four of the eight specimens were prepared for observation under transmission electron microscopy. The results showed that platelets adhered onto the subendothelial substances and formed platelet thrombi in the endothelial lacerations within 5 min after the carotid clamping.

Animals↗