Search PubMed⌕ Search

Biomedical subjects

T W Chen

Publications and source records attributed to T W Chen.

At least 37 records · Page 2Linked to original sources
PubMed1998

Assessing recurrent fall risk of community-dwelling, frail older veterans using specific tests of mobility and the physical performance test of function.

BACKGROUND: The purpose of this prospective cohort study was to determine if older individuals at risk for recurrent falls are best identified by mobility or functional assessments. METHODS: Eighty-four community-dwelling, frail male veterans, mean age of 75.5 years (SD=7.33), participated. The history of recurrent falls was determined by self or proxy report in a clinical interview. Mobility assessments included the Modified Gait Abnormality Rating Scale (GARS-M), stride length, and walking velocity; functional performance was determined using the Physical Performance Test (PPT). The clinical usefulness of the measures was described by determining the sensitivity and specificity of each measure using the history of recurrent falls as a standard. RESULT: Stepwise logistic regression analysis of the data indicated that the GARS-M (p < .01) and the PPT (p < .01) were the most important predictors of recurrent fall risk. The sensitivity and specificity of the measures used were: GARS-M, 62.3% and 87.1%; PPT, 79.3% and 71.0%; walking speed, 71.7% and 74.2%; and stride length, 63.2% and 77.4%. Together the GARS-M and PPT demonstrated the highest sensitivity of 90.6% and the highest specificity of 87. 1% based on a subject testing positive on at least one test. CONCLUSION: Used independently and in combination, the GARS-M and the PPT were clinically useful measures in screening for older individuals at risk for recurrent falls.

Accidental Falls↗
PubMed1998

Focal segmental glomerulosclerosis after poststreptococcal glomerulonephritis in the elderly: a case report.

Acute poststreptococcal glomerulonephritis (PSGN) is quite rare in the elderly population. It is very difficult to recognize because the initial symptoms are similar to those of more common diseases of this age group. Compared with younger patients, elderly patients with PSGN tend to have a high incidence of renal function impairment and anuria or prolonged oliguria. Recovery from acute PSGN in the elderly is less predictable than in children and younger adults, especially when associated with severe impairment of renal function. We present the case of an elderly patient with PSGN, who had a skin infection of the face and anuria on admission. Percutaneous left renal biopsy was performed in the initial hospitalization period and in the recovery phase of the disease. Renal function recovered within two months. However, increased urinary white blood cell sediments with normal serum creatinine concentrations persisted in the successive three years of follow-up. Renal biopsy was repeated and showed evidence of focal segmental glomerulosclerosis.

Aged↗
PubMed1997

Mathematical approach for estimating iron needs in hemodialysis patients on erythropoietin therapy.

Functional iron deficiency occurs when recombinant human erythropoietin (rHuEPO) accelerates erythropoiesis to an extent that the iron availability cannot meet the anticipated demand. Such a phenomenon will reduce the optimal response to rHuEPO. To estimate the iron needs of functional iron deficiency in hemodialysis patients on rHuEPO therapy, we utilized a mathematical method. Forty hemodialysis patients were examined in the study, and all had a baseline serum ferritin (SF) level > 100 microg/l. They were stratified into patients with a transferrin saturation (TfS) value > or = 25% (group I) and those below this value (group II). The treatment protocol consisted of rHuEPO therapy in the two groups for 6 months and iron supplement only in group II. The target hemoglobin level was 10.5 g/dl, and iron metabolism indices were analyzed prior to and following therapy. The results showed (1) in group I (n = 20) hemoglobin rose from 7.5 +/- 0.9 to 10.7 +/- 0.7 g/dl (p < 0.01) and the mean SF level declined from 1,583 +/- 997 to 968 +/- 664 mg (p < 0.01); (2) in group II (n = 20) hemoglobin also increased from 7.8 +/- 0.9 to 10.6 +/- 0.8 g/dl (p < 0.01) following iron supplement, while the SF rose from 183 +/- 70 to 326 +/- 125 mg (p < 0.01); (3) TfS was significantly elevated in group II following iron therapy (18.9 +/- 4.8 vs. 34.5 +/- 9.1%, p < 0.01), and (4) the nomogram showed a sensitivity of 80%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 83% in estimating the iron status before rHuEPO therapy. We conclude that SF levels reflect iron stores and that TfS < 25% is an index of functional iron deficiency. Iron supplementation is not necessary in patients with SF > 100 microg/l and TfS > or = 25%. It seems rational to provide intravenous iron in EPO-resistant patients with functional iron deficiency (SF > 100 microg/l, TfS < 25%). This paper illustrates the importance that accurate assessment of iron needs by a mathematical method would enhance treatment efficacy and avoid iron overload in hemodialysis patients on rHuEPO therapy.

Anemia↗
PubMed1997

Linkage analysis of families with autosomal dominant polycystic kidney disease by KG8-CA marker.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic diseases of human. Traditionally, ADPKD is diagnosed by ultrasonography, computed tomography (CT) or magnetic resonance imaging (MRI) of kidneys for the presence of renal cysts. Individuals who carry the defective gene but have not yet developed cysts in kidney may not be diagnosed. Genetic analysis reveals it to be caused mostly by a single-gene disorder of a genetic locus, designated PKD1. Recently, the genetic locus involving PKD1 has been identified on chromosome 16p13.3, and has been cloned and completely sequenced. METHODS: A pair of primers, KG8-CA, located between D16S84 and D16S125, was selected and synthesized for the polymerase chain reaction (PCR) to identify individuals who may carry the defective locus. The sequence of KG8-CA primers, was 5'-CTCCCAGGGTGGAGGAAGGTG-3' and 5'-GCAGGCACAGCCAGCTCCGAG-3'. PCR products were analyzed in denaturing condition, using gel containing 8% acrylamide and 7M urea. Autoradiography was carried out to interpret the results. RESULTS: Four Chinese families with history of ADPKD showed different DNA patterns in individuals with ADPKD and in normal individuals. Among the members in four families with history of ADPKD, every individual shared a common DNA band, suggesting that this band was derived from normal PKD1 allele. On the other hand, individuals diagnosed to have ADPKD showed one or two additional DNA bands which migrated differently from the common DNA band and should therefore be derived from defective ADPKD allele. Previous studies have shown that the ADPKD allele is highly polymorphic, as was evident in these family studies. CONCLUSIONS: Among the members from these four families, some were clinically normal and had DNA pattern that was typical to patients with ADPKD. These individuals might carry the defective PKD1 allele but have not yet developed the ADPKD symptoms. Therefore, the method described in this study has diagnostic values for pre-symptomatic individuals as well as for patients already diagnosed with ADPKD.

Female↗
PubMed1996

Serum procarboxypeptidase B, amylase and lipase in chronic renal failure.

Procarboxypeptidase B (human pancreas-specific protein) has been reported to be a good serum marker for the diagnosis of acute pancreatitis. The current study was conducted in order to evaluate the frequency and degree of elevated serum levels of procarboxypeptidase B in chronic renal failure and their correlations with serum levels of amylase, lipase and renal function tests. Blood samples were taken from 84 asymptomatic patients with chronic renal failure, including 34 patients with periodical haemodialysis and 50 patients without haemodialysis. Serum levels of procarboxypeptidase B, amylase, lipase, creatinine and blood urea nitrogen were measured. Serum levels of procarboxypeptidase B in 84 patients were 63.4 +/- 5.5 micrograms/L significantly greater than the figure of 29.6 +/- 1.6 micrograms/L in healthy adults in our previous report (P < 0.0001). There was a significant difference in serum levels of PCPB between patients with and without haemodialysis (78.0 +/- 9.4 vs 53.6 +/- 6.3 micrograms/L; P < 0.01). The frequencies of elevated serum levels of procarboxypeptidase B, amylase and lipase greater than upper normal limits were 27.4, 35.7 and 26.2%, respectively. The frequencies of elevated PCPB in patients with and without haemodialysis were 38.2 and 20%, respectively. Only one patient had a serum procarboxypeptidase B level greater than three-fold the upper normal limit. A significant correlation was found between procarboxypeptidase B and lipase (r = 0.785; P < 0.0001). No significant correlation was noted between procarboxypeptidase B vs amylase or renal function tests. In conclusion, in patients with chronic renal failure, the elevation of serum procarboxypeptidase B is as common as the elevations of other pancreatic enzymes.

Aged↗
PubMed1995

Iron metabolism indices for early prediction of the response and resistance to erythropoietin therapy in maintenance hemodialysis patients.

A prospective study with 65 maintenance hemodialysis (MHD) patients on recombinant human erythropoietin (rHuEPO) therapy was conducted to assess the effect of iron balance on responsiveness. An attempt to define the predictors of erythropoietin (EPO) response and identify the specific causes of EPO resistance was undertaken in the present study. The treatment protocol consisted of two stages, the first was rHuEPO therapy for 6 months and the second was iron supplementation plus rHuEPO therapy in patients without response to EPO for the next 6 months. According to the hemoglobin (Hb) changes (increment exceeded 30% of baseline or did not exceed 15% of baseline for 3 consecutive months) and whether or not there was an achievement of target Hb level (>10.5 g/dl), all patients (n = 65) were divided into EPO-responsive (n = 20) and EPO-resistant (n = 45) groups. The EPO-resistant patients were then further stratified into iron-responsive (n = 29) and iron-irresponsive (n=16) groups. Iron metabolism and red cell indices were analyzed prior to and following rHuEPO therapy and iron supplementation.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia↗
PubMed1995

The physiological effect of CO2 pneumoperitoneum in pediatric laparoscopy.

BACKGROUND: The physiological effect of CO2 pneumoperitoneum during laparoscopy is a great concern of the anesthesiologists. Its effect in pediatric laparoscopy has not been previously reported. The purpose of this study was to examine the physiological alteration of pediatric patients during CO2 pneumoperitoneum. METHODS: One hundred and twenty six children aged from 11 mon to 13 yr undergoing laparoscopic inguinal exploration were divided into three groups based on age orientation: group I comprising 40 children with age from 11 mon to 2 yr; group II 46 children with age between 2 to 5 yr; and group III 40 children aged from 5 to 13 yr. All patients received endotracheal anesthesia with halothane-N2O in 50% O2 and atracurium for muscle relaxation. Respiration was controlled by an Ohmeda 7000 ventilator with constant minute ventilation to maintain baseline end-tidal CO2 tension (PETCO2) between 32-33 mmHg. After anesthesia, CO2 was insufflated into the peritoneal cavity via the opened hernia sac. The intraabdominal pressure exerted by CO2 was 10 mmHg and the duration of pneumoperitoneum and laparoscopy was 15 min. We recorded airway pressure, PETCO2, body temperature, blood pressure, heart rate, heart rhythm, and oxygen saturation simultaneously at 1 min interval before, during, and after laparoscopy. RESULTS: The airway pressure and PETCO2 showed significant increases during laparoscopy (15-18% and 18-20% respectively) in all cases, but the percentage of increases were not significantly different among groups. However, the PETCO2 change in terms of time lag were different between groups: (1) the time lag from CO2 insufflation to the emergence of PETCO2 change (latent period) was respectively 0.7 +/- 0.1 (mean +/- SD) min in group I, 0.9 +/- 0.2 min in group II and 1.5 +/- 0.2 min in group III (p < 0.05); (2) the PETCO2 change from baseline to a plateau (ascending period) was respectively 4.2 +/- 0.6 min in group I, 6.3 +/- 1.0 min in group II and 9.1 +/- 1.1 min in group III (p < 0.05); (3) the PETCO2 decline from plateau to baseline after CO2 deflation (descending period) was respectively 6.2 +/- 0.5 min in group I, 8.3 +/- 0.8 min in group II and 12.0 +/- 1.3 min in group III (p < 0.05). The body temperature and hemodynamics including blood pressure, heart rate, heart rhythm, oxygen saturation were not significantly changed during laparoscopy in all groups. CONCLUSIONS: The changes of PETCO2 during laparoscopy did not influence the hemodynamic stability in our study. The younger children give a faster reaction time of PETCO2 change after CO2 insufflation than do the older children which may be related to the variation of physiological exhibition at different state of development.

Adolescent↗
PubMed1994

Mucopolysaccharide histochemistry of the oviduct of the toad, Bufo melanostictus, before and during ovulation.

In both non-ovulating and ovulating toads of the species, Bufo melanostictus, the fimbrium stained only weakly for mucopolysaccharides (MPs) whereas the infundibulum stained strongly for neutral MPs and also for glycogen. In the non-ovulating toad, only neutral and sulphated MPs were detected in the goblet cells of the upper magnum, whereas sulphated, neutral and sialomucins were detected in the glands. In the middle magnum, sulphated and sialic acid-containing carboxylated MPs were detected in both the goblet cells and glands. In the lower magnum, neutral, sulphated, and sialic acid-containing MPs were detected in the goblet cells and only sulphated and sialic acid-containing MPs were detected in the glands. In the isthmus and ovisac, only sulphated MPs were present in the goblet cells. During ovulation, there was no change in the distribution of sulphated MPs throughout the oviduct. Sialic acid-containing MPs could not be detected in many of the goblet cells of the upper and lower magnum nor in most of the glands of the lower magnum.

Animals↗
PubMed1993

A scanning electron microscopic study of the oviduct of the toad, before and during ovulation.

The surface features of the oviduct of the toad, Bufo melanostictus, was studied under the scanning electron microscope. The epithelial folds show regional variations, being longitudinally disposed in the upper part of the oviduct, spirally arranged in the middle and convoluted in the lower part. There is an abundance of cilia through the oviduct except in the ovisac. Goblet cells are interspersed among the epithelial cells. In between the epithelial folds are openings of tubular secretory glands. During ovulation, there is patchy loss of cilia throughout the oviduct. Most of the goblet cells are empty. On the surface, the cilia are matted together by secretory material which are laid down in layers.

Animals↗
PubMed1992

Spurious hyperchloremia and decreased anion gap in a patient with dextromethorphan bromide.

Although cold syrup containing dextromethorpan bromide is widely administered, the bromism due to cold syrup has not been reported. We report a patient who had negative anion gap with hyperchloremia and conscious loss because of daily intake of cold complex syrup (containing dextromethorphan bromide 0.4 mg/ml, acetaminophen 8.33 mg/ml) for headache for 4-5 years. The bromide content in cold complex syrup resulted in serum levels of bromide that interfered with the automated analyzers for chloride content. When conscious change is due to bromism, hemodialysis instead of forced hydration and diuresis should be performed immediately. Therefore, patients with a markedly negative anion gap with hyperchloremia should be considered as having halide intoxication.

Bromides↗
PubMed1992

Peritoneal clearances of carbon dioxide in the rat.

In our previous rat studies (Kidney Int. 1991; 39: 608-617) we evaluated peritoneal clearances (Cp) representing near exclusively diffusive CO2 transfer: for isosmotic (0.37% dextrose) and hyperosmotic (15% dextrose) solutions with pH 7.2-7.3, CpCO2 were 1.20 +/- 0.08 and 1.84 +/- 0.04 ml/min, respectively. In the present studies we have compared Cp of CO2 gas and HCO3- in anesthetized rats (n = 22) using solutions with dextrose contents as mentioned above but with pH 6.5 or 7.6; we have also evaluated how much Cp CO2 measurements obtained with solutions at these pH values differ from Cp shown earlier with the solutions of pH 7.2-7.3. Cp of CO2 gas and HCO3- were significantly higher under hyperosmotic than isosmotic conditions. The use of solutions of pH different from 7.2-7.3 resulted in higher Cp of CO2 gas: with isosmotic solutions of pH 6.5 and 7.6 mean increases were 25 and 75%, respectively; with hyperosmotic solutions respective increases were 45 and 134%. We conclude that dialysis solution osmolality and pH significantly change Cp of CO2 gas and HCO3- in the rat. For evaluation of peritoneal blood flow from diffusive transfer parameters of CO2 gas, smaller overestimation can be expected when dialysis solution pH is slightly under-than overadjusted compared to blood pH.

Animals↗
PubMed1992

A scanning and transmission electron microscopic study of the membranes of chicken egg.

Questions regarding the structure of the inner and outer shell membranes of the chicken egg were addressed in this study by correlating observations from light microscopy and scanning and transmission electron microscopy. The egg membrane had a limiting membrane, which measured .9 to .15 microns in thickness and appeared to be a continuous and an impervious layer, but the shell membrane did not. Under the SEM, each membrane was seen to be made up of several fibre layers. In the tear preparations viewed under the SEM two layers were observed in the egg membranes and three to five layers in the shell membrane, with an apparent plane of cleavage between each layer. Each fibre was made up of a central core and an outer mantle layers. The central core was perforated by channels which measured .08 to 1.11 microns in diameter and ran longitudinally along the length of the fibre. Between the mantle layer and the fibre core was a gap or cleft measuring between .03 to .07 microns. The diameter of the fibres of the inner layer of the egg membrane ranged between .08 to .64 microns, whereas those of the outer layer of the same membrane ranged from .05 to 1.11 microns. Fibres in the shell membrane ranged from .11 to 4.14 microns diameter.

Animals↗
PubMed1991

Ultrafiltration and effective peritoneal blood flow during peritoneal dialysis in the rat.

The dependence between maximum net ultrafiltration rate (nUFR) created by 15% dextrose dialysis solution and effective peritoneal capillary blood flow (EPBF) estimated by the diffusive mass transport coefficient (KBD) and peritoneal clearance (Cp) of CO2 gas was evaluated during 30 minute, 15 ml peritoneal dialysis exchanges in anesthetized rats (N = 18). The values of KBD for CO2 suggested a mean EPBF of 1.9 +/- 0.1 (SEM) ml/min for isosmotic exchanges and 2.7 +/- 0.2 ml/min for hyperosmotic ones with a mean maximum nUFR of 0.43 +/- 0.01 ml/min. Cp of CO2 measured after the first five minutes of dwell underestimated EPBF. In normally hydrated rats, maximum nUFR was achieved when the peritoneal filtration fraction was 32 +/- 2%. This value is similar to the glomerular filtration fraction in rats of 30%. Thus, our results indicate the following relationships: EPBF = (approximately 3 x maximum nUFR)/(1 - hematocrit). EPBF was about six times greater than maximum nUFR and exceeded about 57 times nUFR obtained under isosmotic conditions. These differences between EPBF and nUFR suggest normal EPBF is not a major limiting factor for maximum ultrafiltration achieved during peritoneal dialysis.

Animals↗