Biomedical subjects

C W Yang

Publications and source records attributed to C W Yang.

116 records · Page 7Linked to original sources

PubMedDate not supplied

MRI manifestations of gastrointestinal lymphoma.

The magnetic resonance (MR) images of 11 cases of gastrointestinal lymphoma are presented. The findings include irregularly thickened mucosal folds, irregular submucosal infiltration, annular constricting lesion, exophytic tumor growth, mesenteric masses, and mesenteric/retroperitoneal lymphadenopathy. The tumors were homogeneous and intermediate in signal intensity on T1-weighted images. Heterogeneously increased signal intensities were noted on T2-weighted images. There was mild to moderate enhancement after intravenous administration of gadolinium dimeglumine (Gd-DTPA). The submucosal tumor infiltration might be outlined between the strongly GD-DTPA-enhanced mucosa and the low-intensity muscular layer. In one case that received tumor resection, the pathological examination showed destruction of most parts of the muscular layer, and the MR images did not disclose the low-intensity muscular zone.

Adolescent↗

PubMedDate not supplied

Abdominal pseudotumors and simulated lymphadenopathy in MRI: differential features with the use of retrograde air insufflation.

In order to evaluate the contribution of retrograde air insufflation in decreasing the occurrence of pseudotumor appearance and mimicked lymphadenopathy due to nonair-distended bowel loops, we retrospectively compared two groups of magnetic resonance (MR) examinations. In the group receiving retrograde air insufflation, 10.8% (67 of 619) of images showed a tumor-like lesion due to nonair-distended bowel loop(s), whereas in the group not receiving air introduction, a tumor-like lesion was simulated in 45.6% (140 of 307) of images. Furthermore, a collapsed bowel loop(s) mimicking an enlarged lymph node close to the aorta, inferior vena cava, or bilateral iliac vessels was found in 9.5% (24 of 252) of images of the latter group, in contrast to only 1.8% (9 of 505) of images of the former group. This study shows that retrograde air insufflation greatly reduces the occurrence of pseudotumor appearance and false impression of paraaortic, paracaval, or parailiac lymphadenopathy secondary to nonair-distended bowel loop(s).

Abdomen↗

PubMedDate not supplied

Orthogonal subspace projection-based approaches to classification of MR image sequences.

Orthogonal subspace projection (OSP) approach has shown success in hyperspectral image classification. Recently, the feasibility of applying OSP to multispectral image classification was also demonstrated via SPOT (Satellite Pour 1'Observation de la Terra) and Landsat (Land Satellite) images. Since an MR (magnetic resonance) image sequence is also acquired by multiple spectral channels (bands), this paper presents a new application of OSP in MR image classification. The idea is to model an MR image pixel in the sequence as a linear mixture of substances (such as white matter, gray matter, cerebral spinal fluid) of interest from which each of these substances can be classified by a specific subspace projection operator followed by a desired matched filter. The experimental results show that OSP provides a promising alternative to existing MR image classification techniques.

Brain↗

PubMedDate not supplied

A hierarchical model for PACS.

In this paper, a hierarchical model for Picture Archiving and Communication Systems (HPACS) is presented and implemented at Taichung Veterans General Hospital (TCVGH) in Taiwan. Despite the fact that the HPACS is built on the architecture of the second generation PACS, it offers many improved features and has advantages over the second generation PACS, such as the user security control, fast resource dispatch and efficient resource management. This HPACS can be used as a reference model for a hospital with any scale-size. The real implementation of HPACS is currently undertaken in the Taichung Veterans General Hospital (TCVGH), Taiwan, Republic of China and consists of four phases with the first two phases already completed. It is the first pilot system ever to be implemented successfully in a large-scale hospital in Taiwan. The experiences have illustrated the great promise of the HPACS in the future.

Computer Communication Networks↗

PubMedDate not supplied

Oral supplementation of L-arginine prevents chronic cyclosporine nephrotoxicity in rats.

This study was performed to evaluate the effect of L-arginine (L-Arg) on the prevention of chronic cyclosporine (CsA) nephrotoxicity in rats. Rats pair-fed a low-salt diet (0.05%) were given CsA (15 mg/kg/day s.c.), CsA and L-Arg (L-Arg group, 1.25 g/l water), CsA and N-nitro-L-arginine methyl ester (L-NAME group, 70 mg/l water) or vehicle. After 28 days, the L-Arg group had a higher glomerular filtration rate compared to the CsA (0.42 +/- 0.05 vs. 0.31 +/- 0.06 ml/min/100 g, p < 0.05) and the L-NAME groups (vs. 0.19 +/- 0.04 ml/min/100 g, p < 0.05) and a significantly lower serum creatinine level compared to the CsA (0.70 +/- 0.06 vs. 0.92 +/- 0.12 mg/dl, p < 0.05) and the L-NAME groups (vs. 1.21 +/- 0.17 mg/dl, p < 0.05). The L-Arg group had less fibrosis, tubular injury (TI), and arteriolopathy than the CsA (fibrosis 0.39 +/- 0.14 vs. 0.74 +/- 0.15; TI 1.3 +/- 0.3 vs. 2.0 +/- 0.1; arteriolopathy 33 +/- 7 vs. 48 +/- 17, p < 0.05, respectively) and the L-NAME groups (fibrosis vs. 1.67 +/- 0.32, TI vs. 2.6 +/- 0.3, arteriolopathy vs. 63 +/- 10, p < 0.05, respectively). Plasma renin activity in the L-Arg group was less than in the CsA (18 +/- 2 vs. 23 +/- 3 ng Ang I/ml/h, p < 0.05) and the L-NAME groups (vs. 30 +/- 3 ng Ang I/ml/h, p < 0.05). Nitric oxide production in L-Arg group was higher than in the CsA (24.2 +/- 1.7 vs. 11.1 +/- 1.5 mumol/24 h, p < 0.05) and the L-NAME groups (vs. 8.4 +/- 1.0 mumol/24 h, p < 0.05). In conclusion, the nitric oxide pathway is associated with the pathogenesis of chronic CsA nephrotoxicity, and exogenous L-Arg supplementation is effective in reducing chronic CsA nephrotoxicity in rats.

Animals↗

PubMedDate not supplied

Access blood flow as a predictor of early failures of native arteriovenous fistulas in hemodialysis patients.

Blood flow imaging using color doppler has proven effective in predicting graft failures in hemodialysis patients, but its effect on native arteriovenous fistulas (AVF) is not well known. This study was performed to investigate whether measurements of the access blood flow can be used as predictors of an early failure of a native AVF in hemodialysis patients. Fifty-three consecutive patients who received native AVF operations were included in this study. Access blood flow was measured at 1 week after operations, and AVF function was followed for 4 months. During the follow-up, access failures developed in 10 patients at 9.8 +/- 3.5 weeks. AVF blood flow was significantly lower in the failure group (n = 10) than in the patent group (n = 43) (450 +/- 214 vs. 814 +/- 348 ml/min, p = 0.003). The incidence of access failures was higher in the patients with a flow <350 ml/min (n = 9) compared to the patients with a flow >350 ml/min (n = 44) (55.5 vs. 11.3%, p = 0.008). The diameters of veins were significantly smaller in the failure group than in the patent group (3.5 +/- 0.5 vs. 4.1 +/- 0.7 mm, p = 0.018). The incidence of diabetes mellitus was higher in the failure group than in the patent group (90 vs. 51%, p = 0.025). However, age, sex, duration from an operation to first cannulation, and different AVF sites did not make a significant difference between the two groups. Our data suggest that access blood flow measurements using color doppler ultrasound during early postoperative periods are useful parameters in predicting an early failure of a native AVF in hemodialysis patients.

Adult↗

PubMedDate not supplied

Successful treatment of massive lower gastrointestinal bleeding caused by mixed infection of cytomegalovirus and mucormycosis in a renal transplant recipient.

We describe a case of lower gastrointestinal bleeding due to mixed infection of cytomegalovirus (CMV) and mucormycosis in a renal transplant recipient. A 33-year-old male received renal transplantation and his clinical course was uneventful. On the 18th postoperative day, acute rejection was developed and this was treated with high-dose methylprednisolone and OKT3. During antirejection treatment, sudden onset massive hematochezia was developed. Emergency colonofibroscopy revealed multiple colonic ulcers and pathologic findings were consistent with mucormycosis and CMV infection. The patient was successfully treated with amphotericin B (1.0-1.5 mg/kg) and ganciclovir (62.5-125 mg/day) for 5 weeks. To our knowledge, this is the first report showing coexistence of mucormycosis and CMV in the colon ulcer base. This finding suggests that CMV infection may trigger fungal infection in the pathogenesis of colonic ulcer.

Adult↗

PubMedDate not supplied

Predialysis glycemic control is an independent predictor of clinical outcome in type II diabetics on continuous ambulatory peritoneal dialysis.

OBJECTIVE: To evaluate the correlation between predialysis glycemic control and clinical outcomes for type II diabetic patients on continuous ambulatory peritoneal dialysis (CAPD). DESIGN: Sixty type II diabetic patients on CAPD were classified into 2 groups according to the status of glycemic control. In group G (good glycemic control), more than 50% of blood glucose determinations were within 3.3-11 mmol/L and the glycosylated hemoglobin (HbA1C) level was within 5-10% at all times. In group P (poor glycemic control), fewer than 50% of blood glucose determinations were within 3.3-11 mmol/L or HbA1C level was above 10% at least once during the follow-up duration. In addition to glycemic control status, predialysis serum albumin, cholesterol levels, residual renal function, peritoneal membrane function, and the modes of glycemic control were also recorded. SETTING: Dialysis Unit, Department of Nephrology of a single university hospital. PATIENTS: From February 1988 to October 1995, 60 type II diabetic patients receiving CAPD for at least 3 months were enrolled. MAIN OUTCOME MEASURES: Morbidities before and during the dialysis period, patient survival, and causes of mortality. RESULTS: The patients with good glycemic control had significantly better survival than patients with poor glycemic control (p < 0.01). There was no significant difference in predialysis morbidity between the two groups. No significant differences were observed in patient survival between the patients with serum albumin greater than 30 g/L and those with less than 30 g/L (p = 0.77), with cholesterol levels greater or less than 5.18 mmol/L (p = 0.73), and with different peritoneal membrane solute transport characteristics evaluated by peritoneal equilibration test (p = 0.12). Furthermore, there was no significant difference in survival whether the patients controlled blood sugar by diet or with insulin (p = 0.33). Cardiovascular disease and infection were the major causes of death in both groups. Although good glycemic control predicts better survival, it does not change the pattern of mortality in diabetics maintained on CAPD. CONCLUSIONS: Glycemic control before starting dialysis is a predictor of survival for type II diabetics on CAPD. Patients with poor glycemic control predialysis are associated with increased morbidity and shortened survival.

Aged↗