Biomedical subjects

D S Chang

Publications and source records attributed to D S Chang.

At least 19 recordsLinked to original sources

PubMed2002

The effect of amniotic membrane extract on the expression of iNOS mRNA and generation of NO in HaCaT cell by ultraviolet B irradiation.

BACKGROUND/PURPOSE: Amniotic membrane (AM) is the innermost fetal membrane, which contains several proteinase inhibitors and expresses several growth factors. Nitric oxide (NO) has been implicated in the pathogenesis of various inflammatory diseases including sunburn and ultraviolet induced erythema. The expression of inducible nitric oxide synthase (iNOS) is up regulated by UVB irradiation and inhibited by TGF-beta and EGF-beta. We evaluated the effect of AM extract on the expression of iNOS mRNA by UV irradiation in HaCaT cell (immortalized human keratinocyte cell line). METHODS: HaCaT cells were irradiated UVB 30 mJ/cm2 and AM extract was added. The iNOS mRNA was isolated by RT-PCR and NO production was assessed by spectrophotometric method based on Griess reaction. RESULTS: The expression of iNOS mRNA was induced by UVB irradiation in HaCaT cell and the expression of iNOS mRNA was higher at 48 h than that at 24 h. AM extract down regulated the induction of iNOS mRNA in HaCaT cell by UVB irradiation. NO generation was increased by UVB irradiation, but down regulated by AM extract treatment in HaCaT cells. CONCLUSION: These results assured that the expression of iNOS mRNA and generation of NO are up regulated by UVB irradiation and showed that AM extract down regulated the induction of iNOS mRNA and decreased generation of NO by UVB irradiation.

Amnion↗

PubMed2001

Administration of adenoviral vectors induces gangrene in acutely ischemic rat hindlimbs: role of capsid protein-induced inflammation.

PURPOSE: The initial purpose of this study was to determine the effects of intravascular adenoviral vector-mediated gene transfer of endothelial nitric oxide synthase (AdeNOS) on experimental hindlimb ischemia in the rat. Unexpectedly, administration of AdeNOS immediately after induction of acute limb ischemia led to limb gangrene. We subsequently sought to define the molecular mechanisms responsible for this unusual effect and to devise adenoviral gene transfer strategies to prevent the development of gangrene in acutely ischemic limbs. METHODS: Phosphate-buffered saline or adenoviral vectors containing the bovine endothelial nitric oxide synthase gene (AdeNOS) or no transgene (Ad-E1) were injected intra-arterially into the hindlimb of a rat under vascular isolation immediately after surgical induction of severe ischemia. Hematoxylin and eosin staining was performed on muscle sections to evaluate inflammation. A separate group of animals was injected with an adenovirus containing a nontranscribable genome, treated with cyclosporine, or received delayed administration of the adenoviral vector. Gene expression after delayed adenoviral gene transfer was assessed with immunohistochemistry, Western blotting, and nitric oxide synthase (NOS) activity assay. RESULTS: Both AdeNOS and Ad-E1 caused gangrene of the entire hindlimb within 12 days in a dose-dependent manner, at a threshold concentration of 1 x 10(9) plaque-forming unit/mL. Adenoviral delivery was associated with more inflammation and edema compared with phosphate-buffered saline histologically. Inactivation of adenoviral DNA transcription did not affect induction of gangrene. However, gangrene was prevented by concurrent immunosuppression with cyclosporine or delayed administration of the vector. Delayed administration allowed adenoviral gene expression as determined by immunohistochemistry, NOS protein levels, and an assay of NOS enzyme activity. CONCLUSION: Intra-arterial administration of adenoviral vectors, under vascular isolation, immediately after induction of acute ischemia causes inflammation and subsequent limb gangrene. The inflammatory response is unrelated to the expression of the recombinant transgene or the adenoviral genome and is likely due to the adenoviral capsid proteins. However, administration of cyclosporine or delayed injection of the adenoviral vector is a method that can be used for adenoviral mediated gene transfer in limb ischemia.

Acute Disease↗

PubMed2001

Identification of bacteria crucial to histamine accumulation in pacific mackerel during storage.

Bacterial growth and histamine formation in Pacific mackerel during storage at 0, 4, 15, and 25 degrees C were monitored. To identify bacterial species contributing to histamine formation, several groups of bacteria were isolated by using selective media under temperatures corresponding to the various storage conditions. Initially, low counts of bacteria were found in the gill, skin, and intestine of fresh fish, and only weak histamine formers were found in the gill. Histamine was found in the muscle when fish were stored above 4 degrees C, and aerobic plate counts reached 10(6) CFU/g. When fish became unsuitable for human consumption by abusive storage, toxicological levels of histamine were always found. The highest level of histamine formed was 283 mg/100 g in 2 days. The optimum temperature for supporting growth of prolific histamine formers was 25 degrees C. The most prolific and prevalent histamine former was Morganella morganii, followed by Proteus vulgaris, both of which were isolated on violet red bile glucose (VRBG) agar. At 15 degrees C, a significant level of histamine was still produced in fish muscle, although prolific histamine formers were less frequently detected than at 25 degrees C. The isolates on thiosulfate citrate bile salts sucrose (TCBS) agar were weak histamine formers and identified as Vibrio parahaemolyticus and Vibrio alginolyticus. At 4 degrees C, less than 57.4 mg/100 g of histamine was found in fish stored for 14 days. Most isolates were natural bacterial flora in the marine environment and identified as weak histamine formers. At 0 degrees C, neither histamine former nor histamine production was detected up to 14 days of storage.

Agar↗

PubMed2001

Arthroscopic evaluation and treatment of scaphoid nonunion.

Scaphoid fractures are one of the most common carpal fractures and heal without complication in a majority of cases. Nonunion of the scaphoid, unfortunately, can occur secondarily to several reasons; namely, delay in treatment, delay in diagnosis, the intra-articular nature of the fracture, the precarious vascular supply of the scaphoid, and significant biomechanical stresses across the fractured scaphoid.

Adult↗

PubMed2000

Clinical application of NMP22 and urinary cytology in patients with hematuria or a history of urothelial carcinoma.

For evaluation of the clinical application of immunoassay for nuclear matrix protein 22 (NMP22 immunoassay) and urinary cytology for early diagnosis and detection of bladder cancer in patients with hematuria and/or a previous history of bladder cancer, 209 urine samples obtained from 137 patients presenting episodes of hematuria or a history of bladder cancer were assayed for NMP22 levels and/or prepared for cytology examination. Biopsy was performed when any visible tumor was identified during cystoscopy examination. The median NMP22 concentrations measured in samples taken from patients with active bladder cancer, from patients with a history of bladder cancer but no active disease, from patients with hematuria, and from healthy volunteers were 18.95, 5.45, 6.39, and 3.75 U/ml, respectively. The urinary NMP22 level recorded for patients with urothelial carcinoma was significantly higher than that noted for individuals without active disease. The sensitivity of the NMP22 assay and of urinary cytology in diagnosing bladder cancer was 69% and 67%, respectively. In contrast, the specificity of these two diagnostic modalities reached 72% and 93%, respectively. The NMP22 assay is slightly more sensitive but less specific than urinary cytology in detecting bladder cancer. This study indicates that determination of urinary NMP22 levels is a useful and noninvasive tool for the detection of bladder cancer because of its high sensitivity. The urinary NMP22 assay may be used as a first-line routine screening method; however, it cannot replace the use of urinary cytology because of its lower specificity.

Carcinoma, Transitional Cell↗

PubMed1999

The role of arthroscopy in the treatment of lunotriquetral ligament injuries.

The treatment of lunotriquetral interosseous (LTIO) ligament injuries is controversial. It is part of a spectrum of injuries involving the ulnar side of the wrist. Associated injuries may play a greater role in the outcome of treatment than does the LTIO injury. Arthroscopy is the most accurate diagnostic tool available for the evaluation of LTIO ligament injuries; it allows diagnosis and often treatment of associated injuries. This article describes the current approach to the diagnosis and treatment of LTIO ligament injuries and related use of arthroscopy.

Arthroscopy↗

PubMed1999

Reconstruction of longitudinal stability of the forearm after disruption of interosseous ligament and radial head excision (Essex-Lopresti lesion).

We have presented a technique for reconstruction of the central band of the interosseous membrane in conjunction with surgical repair of the distal radial joint and radial head prosthesis. With this technique, we address all three anatomic structures that provide longitudinal stability of the forearm, specifically, (1) radial head replacement, (2) interosseous membrane reconstitution, and (3) TFCC repair.

Cartilage↗

PubMed1998

Primary multifocal tuberculous osteomyelitis with involvement of the ribs.

Two cases of primary multifocal tuberculous osteomyelitis with involvement of the rib cage are presented. The lungs were normal and the appearance of the skeletal lesions did not suggest tuberculosis. These lesions were predominantly lytic, with minimal soft tissue involvement. Tuberculosis should be high in the differential diagnosis of multiple destructive bone lesions, especially in patients from regions where tuberculosis is endemic.

Adult↗

PubMed1998

The arthroscopic treatment of avascular necrosis of the proximal pole following scaphoid nonunion.

The authors describe a technique of treating scaphoid nonunions with associated avascular necrosis consisting of arthroscopic resection of the distal pole of the scaphoid combined with radial styloidectomy. The results at 2-year follow-up showed all three patients to have complete relief of their mechanical pain and improvement in their range of motion as well as high satisfaction with the procedure. Modified Mayo Wrist Scores were a mean preoperatively of 60 and postoperatively of 88. Postoperative radiographs showed no increase in the scapholunate gap. However, the capitolunate angle increased from a mean of 3 degrees to 13 degrees . There was no progression of degenerative changes noted. The advantages of this technique include (1) minimal morbidity, (2) relief of mechanical pain, and (3) improved range of motion with no early degenerative changes. The rate and severity of degenerative change following this procedure remain unknown.

Adult↗

PubMed1998

Shaken baby syndrome.

Fourteen cases of shaken baby syndrome seen between 1993 to 1997 at the Kaohsiung Medical College Hospital were reviewed. The common clinical presentations were seizure, respiratory problem and disturbed consciousness. The signs and symptoms of this form of head trauma were nonspecific. The findings may mimic infection, intoxication, seizure disorder or metabolic abnormalities. The CT scan is the most common diagnostic tool in cases of suspected shaken baby syndrome. The common CT findings were acute subdural hematoma followed by chronic subdural hematoma and subarachnoid hemorrhage. One infant died due to delay in seeking medical help. Five patients sustained significant morbidity which included developmental delay, seizure, motor deficit and visual impairment. Early recognition and prompt treatment were key to the overall success of case management. The incidence of shaken baby syndrome can be reduced through public awareness and education of the parents not to shake the baby.

Brain Injuries↗

PubMed1998

Prostatic carcinoma with brain metastasis presenting as a tumor hemorrhage.

Adenocarcinoma of the prostate commonly metastasizes to the lymph nodes and bones, with occasional visceral deposits, however, metastasis to the brain is rare. A case of prostatic carcinoma with brain metastasis presenting as a tumor hemorrhage is reported. The pertinent literature is also reviewed.

Adenocarcinoma↗

PubMed1998

Partial sensory rhizotomy as an alternative treatment of trigeminal neuralgia.

Microvascular decompression is a well established technique in the treatment of medically refractory trigeminal neuralgia when a significant vascular contact is identified during posterior fossa exploration. However, in patients with recurrent trigeminal neuralgia after this type of surgery or if no significant vascular indentation is found during surgery, a partial sensory rhizotomy is often the preferred alternative mode of treatment. For eight such patients, partial sensory trigeminal rhizotomy was performed with the involved distribution. Two patients were cases of previous failure, while the other six cases showed a lack of vascular indentation during operation. All the patient underwent microvascular decompression in addition to partial sensory trigeminal rhizotomy with dissector disruption. Sensory examination was performed during the outpatient department follow-up. In these eight such patients, five had excellent results, two continued to have mild pain that was well controlled with carbamazepine, and one had poor results. The mean follow-up period was 58 months. Our study indicates that sensory loss is compatible with the extent of nerve section and that touch loss is less evidence than sensory loss. Partial sensory trigeminal rhizotomy is recommended as the alternative treatment strategy of choice for patients with trigeminal neuralgia who lack significant vascular contact during operation.

Aged↗

PubMed1998

Contralateral recurrent cerebellar hemangioblastoma--a case report.

Hemangioblastomas are regarded as benign neoplasms. They may recur in 3 to 10% of cases after apparently total excision. The opposite site recurrence is not found in the reported literature. A case is described in which, after successful removal of a cerebellar hemangioblastoma followed by two years of freedom from symptoms, developed a new growth of cerebellar hemangioblastoma contralaterally again. The histology of the tumor tissue is in no way different from that of a conventional hemangioblastoma. This case gives us some insights into the biological multipotentiality of cerebellar hemangioblastoma. We stress that close observation is absolutely necessary for this unique group of tumors, even after total removal.

Adult↗

PubMed1998

Primary intraventricular hemorrhage in adult--an analysis of 24 cases.

Primary intraventricular hemorrhage in adults is rare, comprising only about 3.1 % of all intracranial hemorrhage. One of the major management tasks is to find out whether the hemorrhage is secondary to underlying structural vascular abnormality, such as arteriovenous malformation (AVM) and aneurysm, so that appropriate treatment can be carried out to prevent rebleeding. We retrospectively analyzed 24 patients with computerized tomography findings of intraventricular hemorrhage in our hospital from 1991 to 1996. Cerebral angiography was performed in eighteen patients. Eight patients (57%) had positive angiographic findings (five were AVM and three were aneurysm). The angiographic yield was five of seven patients (72%) younger than 45 years of age and three of eleven (27%) older than 45 years of age. On the basis of our results, we suggest that cerebral angiography should be considered for all primary intraventricular hemorrhage patients who are younger than 45 years old.

Adolescent↗

PubMed1997

Mice with genetic gamma-glutamyl transpeptidase deficiency exhibit glutathionuria, severe growth failure, reduced life spans, and infertility.

A mouse mutant with glutathionuria was discovered by screening for amino acidurias in the progeny of ethylnitrosourea-mutagenized mice. Total glutathione concentration was increased in both blood and urine but decreased in liver homogenates from affected mice. Glutathionuric mice exhibited lethargy, severe growth failure, shortened life spans and infertility. gamma-Glutamyl transpeptidase activity was deficient in kidney homogenates of glutathionuric mice. The glutathionuric phenotype in these mice is inherited as an autosomal recessive trait. This mouse mutant will be a useful animal model for the study of gamma-glutamyl transpeptidase physiology and glutathione metabolism.

Animals↗

PubMed1997

The contribution of supraspinal, peripheral and intrinsic spinal circuits to the pattern and magnitude of Fos-like immunoreactivity in the lumbar spinal cord of the rat withdrawing from morphine.

Withdrawal from morphine evokes increases in Fos-like immunoreactivity in the spinal cord, particularly in the superficial dorsal horn, laminae I/II. To determine the origin of the increased Fos-like immunoreactivity, we selectively targeted central or peripheral opioid receptors with naloxone-methiodide, an antagonist that does not cross the blood-brain barrier, or induced withdrawal after eliminating possible sources of input to the superficial dorsal horn. To induce tolerance, we implanted rats with morphine or placebo pellets (75 mg, six pellets over three days). On day 4, withdrawal was precipitated and after 1 h, the rats were killed, their spinal cords removed and 50 microm transverse sections of the spinal cord immunoreacted with a rabbit polyclonal antiserum directed against the Fos protein. In placebo-pelleted rats, none of the different procedures, viz. spinal transection, unilateral dorsal rhizotomy (L4-S2), neonatal capsaicin treatment or direct intrathecal opioid antagonist injection, induced expression of the Fos protein. However, both spinally transected and rhizotomized withdrawing animals showed significant increases in Fos-like immunoreactivity in laminae I/II, compared to intact withdrawing rats. Neonatal treatment with capsaicin, which eliminates C-fibres, did not alter Fos-like-immunoreactivity. Selective withdrawal of morphine from peripheral opioid receptors by naloxone-methiodide did not induce Fos-like immunoreactivity in the lumbar spinal cord greater than that recorded in nonwithdrawing rats. However, intrathecal injection of naloxone-methiodide increased Fos-like immunoreactivity in laminae I/II and the ventral horn to a greater extent than did subcutaneous injection of naloxone. We hypothesize that the increased Fos expression after systemic withdrawal in spinally-transected rats results from a loss of descending inhibitory control that is activated during withdrawal. The increase in withdrawal-induced Fos-like immunoreactivity after rhizotomy may be secondary to loss of inhibitory controls exerted by large diameter primary afferents or to deafferentation-induced reorganization in the dorsal horn. Since capsaicin did not alter the magnitude of Fos-like immunoreactivity in withdrawing rats, we conclude that hyperactivity of opioid receptor-laden C-fibres is not a necessary contributor to the withdrawal-induced increase in Fos-like immunoreactivity in laminae I and II. Taken together with the results recorded after intrathecal injection of naloxone-methiodide in tolerant rats, we conclude that the pattern of lumbar spinal cord Fos expression following systemic withdrawal is primarily a consequence of increased activity in opioid receptor-containing circuits intrinsic to the dorsal horn and that the magnitude of Fos expression is normally dampened by supraspinal and primary afferent-derived inhibitory inputs.

Animals↗

PubMed1997

The familial occurrence of brain tumors.

This is a report of two parent-child families which developed intracranial neoplasm. There is no known history of brain tumor in other family members. Two instances of familial brain tumors are reported which are different from those seen in phakomatosis. Family one had posterior fossa tumors including astrocytoma and hemangioblastoma. The second family had endocrine-associated tumors consisting of pituitary adenoma and yolk sac tumor.

Adenoma↗

PubMed1997

Anesthetic management in parturients with uterine rupture preoperatively--report of two cases.

Uterine rupture is a rare obstetric emergency, and the diagnosis of rupture is not always obvious. High surgical delivery rate today which tends to increase the incidence of the disaster urged us to present this report. Two cases of spontaneous rupture of uterus are described. Case 1 concerns spontaneous rupture of a previously intact uterus; case 2 is a rupture due to placenta percreta. A review relevant to its incidence, risk factors, clinical characteristics, and anesthetic managements is given.

Adult↗