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Biomedical subjects

J B Chen

Publications and source records attributed to J B Chen.

At least 37 records · Page 2Linked to original sources

Lymphovascular clearance in laparoscopic surgery of cancer in low rectum.

BACKGROUND: The success of laparoscopic biliary surgery has encouraged application of laparoscopic surgery in colorectal disease. There are some questions regarding laparoscopic colorectal surgery, especially for colorectal cancer. Most important is whether adequate resection of colorectal malignancy can be achieved. A retrospective study was performed to evaluate the pathology of resected specimens following laparoscopic surgery and that following open surgery in cancer of the low rectum. Comparing the number of lymph nodes in specimens, we could then prove whether laparoscopic surgery can provide adequate clearance as well as open surgery and if laparoscopic surgery has no difference in comparison with open surgery. METHODS: The retrospective study was performed to evaluate the pathology of resected specimens following laparoscopic surgery and that following open surgery in cancer of the low rectum. Data regarding patient details and tumor pathology were obtained by case-note review and from Taichung Veterans General Hospital from July, 1998 to April, 1999. There were nine patients with rectal carcinoma in the low rectum who received laparoscopic surgery, 7 male and 2 female. The control group had 8 patients, 7 male and 1 female, with similar tumor location who received similar operation with open method by the same surgical team in the same period. The average age was 67.7 years in the laparoscopic group and 67.4 years in the control group. The characteristics of tumor and the location of tumor were well matched between these two groups. RESULTS: All of the resected specimens in the two groups were free of tumor in margin of clearance. The average number of lymph nodes harvested was 13 in the laparoscopic group and 9.4 in the open group. CONCLUSIONS: Although the case number was not adequate, the clinical implication is obvious. Laparoscopic surgery in cancer of the low rectum allows lymphovascular clearance even better than that is afforded by open surgery.

Adult↗

Minimal change nephrotic syndrome associated with malignant thymoma: case report and literature review.

We report on a patient with nephrotic syndrome with myasthenia gravis and malignant thymoma status post thymectomy and radiotherapy. This 44-year-old woman underwent a thymectomy and localized radiotherapy for invasive thymoma in 1991. She also took azathioprine and pyridostigmine regularly for the control of her symptoms of myasthenia gravis following thymectomy. Neither evidence of recurrence of myasthenia gravis, nor enlargement of residual thymoma was noted following treatment in 1991. Unfortunately, this patient developed a pronounced nephrotic syndrome in 1999, a renal biopsy revealing a minimal-change glomerulonephritis as being present. The patient entered remission subsequent to steroid and cyclosporin therapy, whereas many previously-reported cases of a similar nature either died or remained with a persistent proteinuria. Herein, we review the literature pertaining to examples of nephrotic syndrome for those patients diagnosed with malignant thymoma, and discuss the possible mechanisms for this association, and emphasize the need for the aggressive treatment of the condition, recommending the early use of steroids and cyclosporins.

Adult↗

Implications of sonographic identification of duplex kidney in adults.

BACKGROUND: Duplication of the renal pelvis and ureter constitutes the most common anomalies of the upper urinary tract. Most patients are asymptomatic and don't need treatment. However, the associated anomaly and acquired renal disease may cause morbidity and mortality. The aim of this study was to investigate the prevalence of duplex kidney in sonographic examinations and the predictive capability of this method. An analysis of patients with urography-confirmed duplication anomaly was also performed. METHODS: During a period of 9 year (from 1988 to 1996), sonographic examination records of 19,287 patients were reviewed. Patients with a diagnosis of duplex kidney were enrolled. Their clinical characteristics and radiological images were recorded and evaluated. RESULTS: One hundred and sixty-three patients were found by sonography to have duplex kidney, for an prevalence of 0.85%. Urography studies were done on 64 (39.2%) patients, and 42 patients were proven to have duplex kidney. The positive predictive rate of sonography was 65.6%. Eighty percent of patients with duplex kidney had associated ureteral duplication. No associated anomalies were found. Four patients had urolithiasis, and 3 patients had recurrent urinary tract infection. One patient had coexisting uroepithelial malignancy, and 1 patient had refractory gross hematuria. CONCLUSIONS: Duplex kidney is an uncommon finding during adult sonographic examinations. The sensitivity and specificity of sonography in identifying this anomaly are controversial. An experienced hand with good knowledge of the anomaly and its sonographic signs is helpful in more accurately diagnosing this anomaly.

Adolescent↗

[Random amplified polymorphic DNA analysis of Cryptosporidium species and strains].

OBJECTIVE: To analyse the genetic heterogeneity of 8 isolates of Cryptosporidium belonging to three species (Cryptosporiduim muris, Cryptosporiduim parvum and Cryptosporidium meleagridis) using RAPD technique. METHODS: DNA extracts of the 8 isolates were amplified by PCR using 26 out of 200 primers. The amplified products were separated by agar electrophoresis followed by staining with ethidium bromide. RESULTS: RAPD analysis revealed; 1. Obvious differences among species were found, the average genetic distance being 7.037; 2. Certain differences among different isolates of the same species were found, the average genetic distance being 5.162. CONCLUSION: RAPD could differentiate the common and respective gene fragments of the 8 isolates of Cryptosporidium.

Animals↗

[Studies on chemical constituents of Fragaria ananassa Duch].

OBJECTIVE: To study the chemical constituents from the fruit of Fragaria ananassa. METHOD: Using chromatographic methods to isolate compounds and chemical and spectral methods to elucidate their structures. RESULT: Three compounds, 9, 19-cyclolanost-24-en-3-ol(1), 14-methyl-stigmasta-7, 24(28)-dien-3-ol(2) and beta-sitosterol(3) were isolated from the freeze-dried powder. CONCLUSION: All of the compounds were obtained from this plant for the first time.

Fragaria↗

Hyponatremia in the emergency department.

Hyponatremia is a clinical manifestation of a wide variety of diseases, some of which have high mortality rates. To assess the prevalence, cause, and prognosis of hyponatremia encountered in the emergency department, we conducted a prospective study at a major hospital in southern Taiwan. We included all adult internal medicine patients treated in the emergency department during a 2-month period. Hyponatremia was defined as a serum sodium level below 134 mEq/L, and cases patients were followed till being discharged. Among the 3,784 patients included, 166 case patients were identified. Most (65%) case patients were hypovolemic, and the overall mortality rate was 17.9%. The mortality rate increased as the sodium level decreased, but was not related to gender, age, cause, or serum potassium level. When 21 hyperglycemic patients whose serum sodium levels went beyond 134 mEq/L after the adjustment for blood sugar levels were excluded, the prevalence of true hyponatremia was 3.83%. The most common underlying diseases were those of the gastrointestinal system. It is concluded that hyponatremia is a common condition encountered in the emergency department. The mortality is correlated with the serum sodium level, and adjustment of the level is required in hyperglycemic patients to make a correct diagnosis. Unlike the cases in some other clinical settings, almost all cases of hyponatremia encountered in the emergency department were not iatrogenic and had recognizable underlying diseases. Therefore, more effort is generally required to identify the cause of hyponatremia cases in the emergency department.

Aged↗

Robotic synthesis of 6-[18F]fluoro-L-dopa.

The aim of this study was to develop a method of semi-automated 6-[18F]fluoro-L-dopa (6-[18F]FDOPA) synthesis using a robotic system (Scanditronix Anatech RB III, Uppsala, Sweden). [18F]Fluorine was produced via 20Ne(d,alpha)18F using a Scanditronix MC17F cyclotron (Uppsala). The radiosynthesis was performed by the Scanditronix Anatech RB III robotic system. On average, a typical run produced 16-19 mCi of 6-[18F]FDOPA at end of synthesis (EOS) after 2 h irradiation of the F2/neon gas target. The total synthesis time was 110 min. The retention time of 6-[18F]FDOPA (the radio peak) was 8.2 min, which was consistent with the 6-[19F]FDOPA ultraviolet peak. The radiochemical purity was greater than 97%. A robotic, semi-automated method for 6-[18F]FDOPA radiosynthesis is therefore feasible. The radiation burden for the operator can be reduced as much as possible. Sufficient activity of 6-[18F]FDOPA could be obtained for positron emission tomography studies of dopaminergic function.

Dihydroxyphenylalanine↗

Experience in the treatment of myasthenia gravis with double filtration plasmapheresis.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disease characterized by production of autoantibodies directly against acetylcholine receptors on postjunctional membranes. The treatment modalities of myasthenia gravis include cholinesterase inhibitors, surgical thymectomy, immunosuppressive treatment, and short-term immunotherapies, including plasmapheresis and intravenous immune globulin. Double filtration plasmapheresis (DFP) is a new technique of plasmapheresis. The aim of our study is to evaluate the effectiveness and complications of DFP in the treatment of MG. METHODS: From December, 1993 to August, 1998, a total of 33 patients with MG received 68 courses (total of 299 sessions) of DFP in our hospital. Plasmapheresis volume, drainage volume, treatment duration, heparin dose, and complications were recorded. In addition, clinical responses after DFP were also evaluated. RESULTS: Only 4 courses (5.88%) of treatment were ineffective. Sixty-four courses (94.12%) of treatment lessened disease activity. The complications of DFP included 15 episodes of hypotension (5.01%), 2 of bradycardia (0.67%), 3 of chest pain (1.00%), 7 of dizziness (2.34%), 58 of high transmembranous pressure of plasma separator (19.40%), 3 of high secondary pressure of plasma fractionator (1.00%), 12 of hemolysis (4.01%), 2 of plasma separator clot (0.67%), 2 of plasma fractionator clot (0.67%), 3 of blood leakage (1.00%), and 1 of air embolism (0.33%). There was no mortality associated with the DFP procedure. CONCLUSION: DFP is a safe, convenient, and time-saving therapy with rare severe complications in the treatment of MG. Our experience confirms its effectiveness when used in combination with drug therapy and thymectomy.

Adult↗

Idiopathic myelofibrosis associated with renal extramedullary hematopoiesis and nephrotic syndrome: case report.

Idiopathic myelofibrosis is characterized by bone marrow fibrosis, anemia, leukoerythroblastosis, and extramedullary hematopoiesis in many organs. Renal abnormalities in idiopathic myelofibrosis have been rarely described in the literature and include extramedullary hematopoiesis in the pararenal or retroperitoneal areas resulting in obstructive uropathy and hemtopoietic cell infiltration in tubulointerstitial area and urolithiasis. These lead to azotemia or acute renal failure, which may respond well to radiotherapy and adjuvant chemotherapy. To our knowledge, there has been only one case report of nephrotic syndrome associated with glomerulonephritis in a myelofibrosis patient; however, no effective treatment was described. Herein, we report the case of a patient with idiopathic myelofibrosis who initially presented with hepatomegaly, anemia, and leukoerythroblastosis. A nephrotic syndrome developed 7 years after initial diagnosis. Renal biopsy disclosed the unique pathological finding of simultaneous mesangial proliferative glomerulonephritis, renal extramedullary hematopoiesis, and gouty nephropathy. Despite treatment with busulfan, proteinuria persisted that implied irreversible glomerular injury and a terminal prognosis. We focus on the unusual pathological finding and the association between nephrotic syndrome and idiopathic myelofibrosis.

Aged↗

Development of a mouse cell line containing the PhiX174 am3 allele as a target for detecting mutation.

Transgenic mice containing multiple copies of the PhiX174 am3 allele are being developed as a model for detecting tissue-specific in vivo mutation. In order to derive an analogous system for measuring am3 mutation in vitro, cells were cultured from 15-day-old C57Bl/6J mouse embryos that were homozygous for the transgene and these cells were transfected with a plasmid expressing the SV40 large T-antigen. Two G418-resistant colonies were isolated from this culture and expanded to continuously proliferating cell lines (PX-1 and PX-2). Line PX-2 was treated with up to 1.0 mg/ml of N-ethyl-N-nitrosourea (ENU), assayed for survival by cloning efficiency after overnight culture, and assayed for am3 mutations after 5 days of culture. Survival decreased to 31% at the highest dose of ENU, while mutant frequency increased with dose from approximately 2 x 10(-7) in the untreated cells to 13 x 10(-7) in cultures treated with 0.6 mg/ml of ENU. PX-2 cells also were treated with 0 and 0.6 mg/ml of ENU and mutant frequency assays were performed after 5, 24, 48 and 72 h of growth. The mutant frequency in the treated culture increased to 20 x 10(-7) at 48 h and remained approximately the same at 72 h. These results indicate that PX-2 cells should be a useful resource for developing the in vivo am3 mutant assay and for evaluating the sensitivity of the am3 allele to various classes of mutagens.

Alleles↗

Process control procedures to augment quality control of leukocyte-reduced red cell blood products.

Quality control of leukocyte-reduced packed red cell units (LRprc) produced in blood facilities must conform to regulatory criteria, which state that units may not contain more than 1 x 10(6) to 5 x 10(6) white blood cells (WBC) per unit. The post-filtration WBC content of a total of n = 386 LRprc units was counted with a Nageotte chamber to model the probability that a unit would not meet the regulatory criteria. The distribution of the residual leukocyte counts is close to a negative binomial distribution (NBD) and is independent of the packed red cell volume filtered. The observed probability that a unit of blood has a residual WBC greater than 5 x 10(6) is 2.6 +/- 2.6 x 10(-3). A power analysis of the two-sample Kolmogorov-Smirnov (KS) test in this application shows that a sample size of 20 is sufficient for determining that the process is in control when an out of control process has a k NBD parameter greater than or equal to that of the in control process. The three out of control processes observed to date appear to have this property. A sample of size 80 may be necessary for confirming that process validation data sets conform to the larger 'reference' database (n = 386) for processes that are out of control in such a way that their k NBD parameter is less than the k parameter of the in control process.

Blood Component Removal↗

An estimator of the mutant frequency in assays using transgenic animals.

The Poisson distribution is a fundamental probability model for count data, and is a natural model for the observed plaque counts in mutation assays using animals with lambda or PhiX174 transgenes. The Poisson likelihood for observed counts is a function of the mutant fraction, and it is straightforward to derive the associated maximum likelihood estimate of the mutant fraction and its variance. The estimate is easy to calculate, and if not the same, very similar to ad hoc estimates in current use. The model indicates the proper way to combine data from a number of plates, possibly prepared with different sample dilutions. The estimator of the mutant fraction is biased as a consequence of dividing by a random variable, the plaque count used to calculate the total recovered plaque-forming units. Fortunately, the bias becomes negligible as this count becomes large. On the other hand, increasing this count can increase the variance by decreasing the amount of sample assayed for mutant phages. Concurrent heed to the bias and the variance provides some guidance as to the optimum allocation of a sample into portions assayed for mutant phages and total recovered phages. The distribution of the estimate of the mutant fraction is related to the binomial distribution. This relationship implies a binomial distribution for the mutant count conditional on an overall count (either the sum of mutant and counted total plaques or the sum of counted mutant and non-mutant plaques). A special but important case occurs when each plate can be evaluated for mutant plaques and non-mutant plaques. Then, the observed proportion of mutants estimates the mutant fraction. More generally, the relationship to a binomial distribution provides a procedure for calculating a confidence interval.

Animals↗

General weakness as an indication for parathyroid surgery in patients with secondary hyperparathyroidism.

HYPOTHESES: There are factors that affect patients with general weakness owing to secondary hyperparathyroidism and as reported by results noted after parathyroidectomy and autotransplantation. DESIGN: Case series and consecutive samples. SETTING: Tertiary care center. PATIENTS: From July 1996 to June 1998, 56 patients with secondary hyperparathyroidism underwent total parathyroidectomy and autotransplantation. Their ages were 45 +/- 13 years (mean +/- SD) and preoperative duration of dialysis was 75 +/- 37 months. Prior to surgery the patients were divided into 2 groups: group A comprised 2 men and 19 women who had some general weakness; and group B, 15 men and 20 women who reported no general weakness. The etiologies of renal failure, such as diabetic nephropathy (n = 3) or hypertensive nephropathy (n = 3), were found only in group A patients. INTERVENTIONS: Serum levels of calcium, phosphorus, alkaline phosphatase, and parathyroid hormone (intact) were checked preoperatively and 1 day, 1 week, and 3 months after surgery. Extension force of the quadriceps femoris muscle was measured at 60 degrees of right knee flexion preoperatively and 3 months after surgery. The extension force was expressed as newtons (N) in 2 different quantities: peak force and average force. The degree of general weakness was classified into 4 groups: 0, no weakness; 1, some subjective weakness and/or walking with assistance; 2, the patient was wheelchair bound; and 3, the patient was bedridden. MAIN OUTCOME MEASURES: The t test was used for paired and unpaired data; Wilcoxon signed rank and Fisher exact tests were incorporated for nonparametric data. Any values of P<.05 were considered significant. RESULTS: Prior to surgery, 2 patients in group A reported degree 3 weakness; 5, degree 2 weakness; and 14, degree 1 weakness. Three months after surgery, the peak force was noticed to have increased from 185 +/- 56 N to 249 +/- 82 N (mean +/- SD) (n = 11, P = .003), and the average force showed an increase from 136 +/- 45 N to 202 +/- 69 N (n = 11, P = .003). Postoperatively, only 5 patients had degree 1 weakness, 1 had degree 2 weakness, and none had degree 3 weakness. The patient with degree 2 weakness after surgery had diabetes mellitus and a femoral neck fracture prior to parathyroidectomy. Improvement in condition of general weakness was found (P<.001) between preoperative and postoperative periods. Serum levels of calcium were higher in group A (2.82 +/- 0.23 mmol/L [11.3 +/- 0.9 mg/dL]) than in group B (2.64 +/- 0.27 mmol/L [10.6 +/- 1.1 mg/dL]) (P = .013), and serum levels of parathyroid hormone (intact) were lower in group A (108.9 +/- 39.2 pmol/L) than in group B (139.8 +/- 39.6 pmol/L) (P = .006). Except for sex, other data such as phosphorus and alkaline phosphatase levels, age, and duration of dialysis were not significantly different between the 2 groups. CONCLUSIONS: General weakness that is commonly observed in patients with secondary hyperparathyroidism is found more frequently in women and only in patients with diabetic nephropathy or hypertensive nephropathy. Patients with general weakness had relatively higher levels of calcium and lower levels of parathyroid hormone (intact). We found that improvement of muscle power and general weakness can be achieved by parathyroidectomy and autotransplantation. In addition to itchy skin, bone pain, and soft tissue calcification, general weakness that may cause disability is also an indication for surgery in secondary hyperparathyrodism.

Female↗

Low dose desferrioxamine can improve erythropoiesis in iron-overload hemodialysis patients without side effects.

OBJECTIVE: Multiple blood transfusions were often required to treat anemia in uremia patients before the era of recombinant human erythropoietin (r-HuEPO). Iron overload thus frequently occurred in chronic hemodialysis patients. Desferrioxamine (DFO) is an effective chelating agent, which can remove excessive iron and can enhance erythropoiesis. Large dose DFO treatment is a therapy associated with the development of severe complications. In this study, a low dose DFO regime was used to treat iron overloaded hemodialysis patients. The efficacy and side effects of this regiment were evaluated. MATERIALS AND METHODS: Eight iron overloaded chronic hemodialysis patients were enrolled in this study. All patients received DFO 500 mg intravenously twice-a-week for eight months. Serum aluminum, transferrin saturation (TFS) and r-HuEPO requirement were recorded before and after DFO treatment. Serum ferritin and hematocrit (Hct) were measured before, during, and after the DFO withdrawal period. All patients were evaluated and followed closely during treatment. RESULTS: Changes in aluminum, TFS and r-HuEPO dosage were unremarkable (p > 0.05). Hct increased significantly after eight months of DFO treatment (from 25.3% to 27.0%, p < 0.05). Ferritin level was reduced by 43.2% at the end of treatment and an evident decline of ferritin was achieved after four months of treatment (2102 ng/mL to 1166 ng/mL, p < 0.05). All patients tolerated the treatment well and no complications were found. CONCLUSION: Low dose DFO can chelate iron effectively in chronic hemodialysis patients. This treatment can enhance erythropoiesis without adverse effects.

Anemia↗

Acute goby poisoning in southern Taiwan.

Food poisoning due to ingestion of two fishes, Yongeichthys nebulosus and Sillago japonica, occurred in Kaohsiung, Taiwan, in February 1997. Two male persons (48 and 58 years old) were poisoned, with symptoms featured by dizziness, nausea, vomiting, numbness, and difficulty in respiration. All of the specimens of fish retained by the victims were combined and consisted of Yongeichthys nebulosus and Sillago japonica. These retained specimens were assayed for anatomical distribution of toxicity (as tetrodotoxin) and all specimens were found to be toxic. The highest toxicity of specimen was 7,650 mouse units (MU) in Y. nebulosus and 1,460 MU in S. japonica. However, the other specimens re-collected from that fish pier were also found to be highly toxic in Y. nebulosus, but nontoxic in S. japonica. Hence, Y. nebulosus was judged as the real causative fish in this food poisoning. The toxins were partially purified from the methanolic extracts of toxic fishes by ultrafiltration and Bio-Gel P-2 column chromatography. Cellulose acetate membrane electrophoresis and high performance liquid chromatography analyses demonstrated that tetrodotoxin was the causative agent of this food poisoning.

Animals↗