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Biomedical subjects

Jainn-Shiun Chiu

Publications and source records attributed to Jainn-Shiun Chiu.

18 recordsLinked to original sources

Neuro-fuzzy technology as a predictor of parathyroid hormone level in hemodialysis patients.

Measuring the plasma parathyroid hormone (PTH) concentration is crucial to evaluate renal bone disease in patients with renal failure. Although frequent measurement is needed to avoid inadequate prescription of phosphate binders and vitamin D preparations, artificial intelligence can repeatedly perform the forecasting tasks and may be a satisfactory substitute for laboratory tests. Neuro-fuzzy technology represents a promising forecasting application in clinical medicine. We therefore constructed a coactive neuro-fuzzy inference system (CANFIS) to predict plasma PTH concentrations in hemodialysis patients. The CANFIS was constructed with clinical parameters (patient age, plasma albumin, calcium, phosphorus, alkaline phosphatase, and calcium-phosphorus product) from a cohort of hemodialysis patients, and plasma PTH concentration measured by radioimmunoassay (RIA) was the supervised outcome. The accuracy of the CANFIS was prospectively compared with RIA in another hospital. Plasma PTH concentrations measured by RIA and predicted by CANFIS were 179.04 +/- 38.18 ng/l and 179.34 +/- 37.76 ng/l, respectively (p = 0.15). The CANFIS was able to precisely estimate plasma PTH concentrations in hemodialysis patients. These results suggest that the neuro-fuzzy technology, based on limited clinical parameters, is an excellent alternative to RIA for accurately predicting plasma PTH concentration in hemodialysis patients.

Aged↗

Prediction of target range of intact parathyroid hormone in hemodialysis patients with artificial neural network.

The application of artificial neural network (ANN) to predict outcome and explore potential relationships among clinical data is increasing being used in many clinical scenarios. The aim of this study was to validate whether an ANN is a useful tool for predicting the target range of plasma intact parathyroid hormone (iPTH) concentration in hemodialysis patients. An ANN was constructed with input variables collected retrospectively from an internal validation group (n = 129) of hemodialysis patients. Plasma iPTH was the dichotomous outcome variable, either target group (150 ng/L 300 ng/L). After internal validation, the ANN was prospectively tested in an external validation group (n = 32) of hemodialysis patients. The final ANN was a multilayer perceptron network with six predictors including age, diabetes, hypertension, and blood biochemistries (hemoglobin, albumin, calcium). The externally validated ANN provided excellent discrimination as appraised by area under the receiver operating characteristic curve (0.83 +/- 0.11, p = 0.003). The Hosmer-Lemeshow statistic was 5.02 (p= 0.08 > 0.05) which represented a good-fit calibration. These results suggest that an ANN, which is based on limited clinical data, is able to accurately forecast the target range of plasma iPTH concentration in hemodialysis patients.

Female↗

Application of upper extremity radionuclide venography as a diagnostic approach for Port-A catheter thrombosis.

BACKGROUND: To investigate the role of upper extremity radionuclide venography as a potential diagnostic modality in the assessment of venous thrombosis associated with a Port-A catheter. METHODS: Fourteen symptomatic patients who had received Port-A catheter implantation were enrolled. A dynamic nuclear medicine flow study was performed with intravenous administration of Technetium-99m macroaggregated albumin to both upper extremities. Imaging patterns of the venous system were categorized as patency, partial obstruction, and total occlusion. RESULTS: The findings of the dynamic images clearly demonstrated clinical problems. Three patients were free of a definite venous flow change. Three patients had partial obstruction of venous return. A significant cut-off of venous return was demonstrated in 8 patients, and total occlusions were hence diagnosed. All patients underwent this procedure smoothly without any complication. CONCLUSION: These results suggest that upper extremity radionuclide venography is an easily performed and effective method for diagnosing Port-A catheter thrombosis in clinical practice.

Adult↗

Applying an artificial neural network to predict osteoporosis in the elderly.

Osteoporosis is an essential index of health and economics in every country. Recognizing asymptomatic elderly population with high risks of osteoporosis remains a difficult challenge. For this purpose, we developed and validated an artificial neural network (ANN) to identify the osteoporotic subjects in the elderly. The study population consisted of 1403 elderly adults (mean age 63.50 +/- 0.24 years ranged from 50 to 91 years old, 157 male and 1246 female) randomly selected into 3 sets, 703 participants in training set, 350 participants in selection set, and the remaining 350 participants in test set. The input variables included demographic characteristics, anthropometric measurements, and clinical data. The outcome variable was dichotomous, either non-osteoporotic (T-score of greater than -2.5) or osteoporotic (T-score of -2.5 or less) groups classified by the measurement from dual energy X-ray absorptiometry. ANN was constructed with data from training and selection sets and validated in test set whose outcome variable was unknown to the network. The performance of ANN was evaluated by discrimination and calibration simultaneously. After training processes, the final best ANN was a multilayer perceptron network which determined seven input variables (gender, age, weight, height, body mass index, postmenopausal status, and coffee consumption) as significant features. The discriminatory power of ANN for test set was excellent (area under receiver operating characteristics curve = 0.82 +/- 0.03). ANN also had statistically good fit represented by statistically insignificant Hosmer-Lemeshow statistic (p = 0.24). These results suggested that our final ANN concurrently had good discriminatory power and good-fit calibration. ANN can be used as a promising tool for the elderly to stratify high risk subjects into osteoporotic group.

Aged↗

Applying an artificial neural network to predict total body water in hemodialysis patients.

BACKGROUND: Estimating total body water (TBW) is crucial in determining dry weight and dialytic dose for hemodialysis patients. Several anthropometric equations have been used to predict TBW, but a more accurate method is needed. We developed an artificial neural network (ANN) to predict TBW in hemodialysis patients. METHODS: Demographic data, anthropometric measurements, and multifrequency bioelectrical impedance analysis (MF-BIA) were investigated in 54 patients. TBW measured by MF-BIA (TBW-BIA) was the reference. The predictive value of TBW based on ANN and five anthropometric equations (58% of actual body weight, Watson formula, Hume formula, Chertow formula, and Lee formula) was evaluated. RESULTS: Predictive TBW values derived from anthropometric equations were significantly higher than TBW-BIA (31.341 +/- 6.033 liters). The only non-significant difference was between TBW-ANN (31.468 +/- 5.301 liters) and TBW-BIA (p = 0.639). ANN had the strongest Pearson's correlation coefficient (0.911) and smallest root mean square error (2.480); its peak centered most closely to zero with the shortest tails in an empirical cumulative distribution plot when compared with the other five equations. CONCLUSION: ANN could surpass traditional anthropometric equations and serve as a feasible alternative method of TBW estimation for chronic hemodialysis patients.

Adult↗

Biochemical and etiological characteristics of acute hyponatremia in the emergency department.

Hyponatremia can be classified as acute or chronic depending on its duration, and treatment options are tailored to this classification. However, it is sometimes difficult to differentiate acute from chronic hyponatremia in the Emergency Department (ED). The objective of this study was to identify characteristics to help diagnose and manage acute hyponatremia in the ED. Patients with acute hyponatremia in the ED were enrolled from a retrospective 2-year chart review. Eleven patients (0.8%) were identified with acute hyponatremia out of a total of 1321 hyponatremic patients. There were nine women and two men. The mean age was 48.9 years. The mean sodium (Na(+)) level was 115+/-4 mmol/L. Accompanying biochemical abnormalities included hypouricemia and hypouremia with increased fractional excretions of uric acid (UA) and urea. The estimated amount of water intake ranged from 2.5 to 10 liters (mean, 5.1+/-2.3 liters) during the day before ED presentation. All patients were treated with hypertonic saline and furosemide at a correction rate of 1.6+/-0.5 mmol/L/h. No patients had neurological sequelae after treatment. The causes of acute hyponatremia included induction of abortion with oxytocin (n=1), primary polydipsia on neuroleptic agents (n=2), polyethylene glycol (PEG) preparation for colonoscopy (n=1), diuretic therapy for hypertension (n=4), ecstasy use (n=1), and weight-reducing herbal teas (n=2). We conclude that in the right clinical setting, high free water intake and low serum urea and UA favor acute hyponatremia. A detailed drug history may be helpful in the differential diagnosis of acute hyponatremia.

Acute Disease↗

Unusual cause of hypokalemic paralysis in aged men: Sjögren syndrome.

Hypokalemic paralysis is a less recognized but reversible disorder in elderly patients. This report describes two elderly Chinese males (age 74 and 78 years) who had progressive muscle weakness and eventually paralysis. Physical examination showed symmetrical flaccid paralysis of extremities. Both had the major biochemical abnormality of profound hypokalemia (1.4 and 1.8 mmol/L) accompanied by high urine K+ excretion and hyperchloremic metabolic acidosis. A positive urine anion gap and alkaline urine pointed to the diagnosis of distal renal tubular acidosis. Large doses of potassium chloride supplementation were required to restore muscle strength. Pertinent investigations, including elevated titers of antinuclear antibody and rheumatoid factor, positive anti-Ro antibody, low serum C3 and C4 levels, and delayed saliva excretion on salivary scintigraphy suggested Sjögren syndrome. Despite the lack of sicca syndrome at the initial presentation, both had development of typical sicca syndrome and positive Schirmer test at the 5-month and 1-year follow-up, respectively. Potassium citrate supplement and prednisolone therapy completely corrected the hypokalemia and metabolic acidosis. Extraglandular involvement with distal renal tubular acidosis preceding the typical sicca syndrome may induce hypokalemic paralysis and unveil Sjögren syndrome in elderly males.

Aged↗

Effects of potassium supplementation on the recovery of thyrotoxic periodic paralysis.

Potassium supplements have been recommended to hasten recovery and prevent cardiopulmonary complications in patients with thyrotoxic periodic paralysis (TPP). However, this recommendation has not yet been proven efficacious. Thirty-two patients with acute attacks of TPP over a 3-year-period were divided into 2 groups. Group A (n = 12) was a control group treated with normal saline infusion 125 mL/hr only. Group B (n = 20) received intravenous KCl administration at a rate of 10 mmol/hr in normal saline 125 mL/hr. During the attack and for 6 hours after muscle recovery, hemodynamics were continuously recorded and muscle strength and plasma K(+) concentration were measured hourly. The sex, age, muscle strength, thyroid function, biochemical values including plasma K(+) levels, as well as the time from attack to therapy (3.6 +/- 1.6 v 3.3 +/- 1.0 hr) were not significant between the 2 groups. However, recovery time was significantly shorter in the KCl group than the control (6.3 +/- 3.8 v 13.5 +/- 7.5 hr, P < .01). Rebound hyperkalemia greater than 5.5 mmol/L occurred in 40% patients receiving KCl. The dose of KCl administered and peak K(+) concentration were positively correlated (r = 0.85, P < .001). In conclusion, KCl therapy proves to help the recovery of paralysis in TPP associated with rebound hyperkalemia. KCl supplementation should be given as small as possible (<10 mmol/hr) to avoid rebound hyperkalemia unless there are cardiopulmonary complications.

Adult↗

A simple and rapid approach to hypokalemic paralysis.

Hypokalemia with paralysis (HP) is a potentially reversible medical emergency. It is primarily the result of either hypokalemic periodic paralysis (HPP) caused by an enhanced shift of potassium (K(+)) into cells or non-HPP resulting from excessive K(+) loss. Failure to make a distinction between HPP and non-HPP could lead to improper management. The use of spot urine for K(+) excretion rate and evaluation of blood acid-base status could be clinically beneficial in the diagnosis and management. A very low rate of K(+) excretion coupled with the absence of a metabolic acid-base disorder suggests HPP, whereas a high rate of K(+) excretion accompanied by either metabolic alkalosis or metabolic acidosis favors non-HPP. The therapy of HPP requires only small doses of potassium chloride (KCl) to avoid rebound hyperkalemia. In contrast, higher doses of KCl should be administered to replete the large K(+) deficiency in non-HPP.

Acid-Base Equilibrium↗

Acute hyperkalemic paralysis in a uremic patient.

Hyperkalemia is a less-recognized life-threatening cause of paralysis. We describe a 38-year-old uremic man on regular hemodialysis (HD) without interruption who suffered from muscle weakness progressing to ascending symmetric paralysis, and inability to masticate. Physical examination revealed flaccid paralysis with areflexia of the four limbs. Computed tomography of the brain and cervical spine did not demonstrate any organic lesions. Laboratory investigations revealed serum K+ 8.1 mmol/L, urea nitrogen 32 mmol/L, creatinine 919 micromol/L. Of note, electrocardiography (ECG) did not show typical features of hyperkalemia. Emergent HD with low K+ dialysate (1.0 mmol/L) rapidly normalized serum K+ (4.7 mmol/L) and reversed all neuromuscular symptoms within one hour. Upon reviewing his food and medication history, he admitted drinking 750 ml of raw coconut juice per day (K+ concentration 44.3 mmol/L) to quench his thirst for three consecutive days. Hyperkalemia should be born in mind in the differential diagnosis of acute paralysis despite no ECG changes. Hidden sources of K+ intake, such as coconut juice, should not be overlooked, especially in patients with impaired renal function.

Adult↗