Biomedical subjects

C S Chang

Publications and source records attributed to C S Chang.

At least 109 records · Page 6Linked to original sources

PubMed1997

Severe granulocytopenia secondary to chlorpromazine despite concurrent lithium treatment: a case report.

Severe chlorpromazine-induced granulocytopenia where the white-cell count decreases to below 1,000/mm3 rarely occurs and lithium is known to cause leucocytosis. The use of lithium in the prevention of granulocytopenia induced by drugs is still controversial. This report describes a patient with bipolar disorder suffering from severe granulocytopenia and severe respiratory infection after receiving chlorpromazine 50 to 150 mg per day along with long term lithium therapy. Bone-marrow aspiration and biopsy revealed inhibited maturation of myeloid series in the promyelocyte stage. The findings were consistent with a drug-induced effect. White-cell count return to normal after the discontinuation of chlorpromazine. It was proved in this case that combined lithium therapy had no effect in preventing agranulocytosis induced by chlorpromazine.

Aged↗

PubMed1997

Leptomeningeal malignant melanoma arising in neurocutaneous melanocytosis: a case report.

A rare case of histology-proved giant congenital melanocytic nevus (GCMN) with symptomatic leptomeningeal melanocytosis is reported. A 26-year-old man had had a large patch of pigmented nevus over his back and left arm since birth. He had begun to have seizures as well as symptoms and signs of increased intracranial pressure about six months before admission. Serial computed tomography of brain showed hydrocephalus, diffuse leptomeningeal enhancement and multiple well-enhanced, rapid-growing nodules on the surface of the cerebellum and left parietal lobe. Magnetic resonance imaging (MRI) revealed T1 shortening of leptomeninges on precontrast T1 weighted imaging. Skin biopsy was done twice and showed intradermal nevus. Biopsy on one of the intracranial nodules revealed malignant melanoma arising in the melanocytosis. He died one year after the onset of neurologic symptoms. For early diagnosis of neurocutaneous melanocytosis, we suggest 1) MRI, and 2) leptomeningeal biopsy in patients with suspected leptomeningeal malignant melanoma.

Adult↗

PubMed1996

Major histocompatibility complex class I-dependent cell binding to isolated Ly-49A: evidence for high-avidity interaction.

Ly-49A molecules negatively regulate a subset of mouse natural killer (NK) cells, preventing lysis of H-2Dd-expressing target cells. In the present report, we immunoaffinity-purified Ly-49A from the EL4 lymphoma using the A1 monoclonal antibody (mAb) and examined cell adhesion to immobilized Ly-49A. Adhesion was observed by cells expressing relatively high levels of H-2Dd, but not cells expressing very low or no cell surface Dd, while antibodies specific for Dd or Ly-49A inhibited the cell binding, indicating that Dd and Ly-49A mediate the observed adhesion. The density of immobilized Ly-49A was varied and confirmed by ELISA. Cell binding exhibited a threshold Ly-49A density requirement, and above this threshold, increases in Ly-49A density resulted in substantial increases in cell adhesion to a high maximum cell binding. The density of Ly-49A homodimers required to mediate cell adhesion was found to be quite low: 140-250 molecules/microm2. These results suggest that the avidity of Ly-49A for Dd is relatively high and indicate that small changes in Ly-49A density near the threshold result in large changes in stable Ly-49A receptor engagement. The relatively sharp threshold and marked density dependence presented here for Ly-49A receptor engagement may explain the observation that relatively small differences in Ly-49A expression level on NK cells result in significant differences in functional outcome, i.e. whether a target cell expressing a low level of Dd is spared from lysis or not.

Animals↗

PubMed1996

Quantitative X-ray imaging of labelled molecules in tissues and cells.

Using cisplatin as a model system, we have been able to demonstrate the feasibility of studying the cellular and subcellular distribution of a labelled molecule containing a single atom of platinum per molecule in bone marrow. An X-ray imaging system consisting of a microcomputer, a 4pi system and a software package was interfaced with an electron microscope enabling the computer to control the beam movements as well as receive signals from the STEM and EDS X-ray detectors. X-ray imaging is useful for both tissue and samples in which the population of cells is not homogeneous. Imaging permits elemental distributions to be measured throughout the sample and not in just randomly selected areas as previously done in X-ray microanalysis. Images are created for not only the element labelling the molecule of interest but also other specified elements present. Three types of maps for imaging labelled molecules are compared and discussed. When the original (collected) data are mapped, the elements of interest are obscured by the continuum. The maps calculated using an internal standard give a concentration distribution on the basis of volume (mmol L(-1) of packed cells). The maps calculated using the continuum normalization method according to Hall produces concentration distribution on the basis of mass (mmolk(-1) dry weight). By recalculating using the 'Peak' or 'Hall' method the continuum problem is removed yielding quantitative images of the intracellular distribution of labelled molecules present in low concentrations.

Animals↗

PubMed1996

Discrepant pattern of solid and liquid gastric emptying in Chinese patients with type II diabetes mellitus.

While abnormal gastric emptying has been widely reported in patients with diabetes, its clinical relevance is still uncertain. We conducted scintigraphic gastric emptying studies in patients with Type II diabetes mellitus who had symptoms suggestive of delayed gastric emptying in an attempt to evaluate the incidence of abnormal gastric emptying and to assess the clinical parameters of the different patterns of gastric emptying. Seventy male diabetic patients were included in the study. The patients were divided into four groups according to the results of liquid and solid gastric emptying: group 1, normal liquid and solid emptying (n = 22); group 2, normal liquid but delayed solid emptying (n = 30); group 3, delayed liquid but normal solid emptying (n = 7); group 4, delayed liquid and solid gastric emptying (n = 11). To assess clinical significance, we compared duration of disease, status of blood sugar control, presence or absence of vascular complications and of peripheral neuropathy among the four groups. Of the 70 patients, 18 (25.7%) showed delayed liquid gastric emptying and 41 (58.6%) delayed solid gastric emptying. There were no significant differences in the clinical parameters of the four groups, except that patients with good sugar control were likely to have normal liquid gastric emptying. Based on the results of this study, delayed solid gastric emptying is more common than liquid gastric emptying in symptomatic Type II diabetes mellitus patients. Of the different patterns of gastric emptying, delayed liquid gastric emptying with normal solid gastric emptying is the most unusual. For Type II diabetic patients with symptoms suggestive of delayed gastric emptying, both liquid and solid gastric emptying studies should be performed.

Aged↗

PubMed1996

Gastric clearance of radiopaque markers in non-ulcer dyspepsia patients.

BACKGROUND: The use of radiopaque markers has been proposed as an easy, non-invasive method for measuring gastric emptying. In this study we intended to evaluate the effectiveness of this test in determining the gastric motor function in patients with non-ulcer dyspepsia. METHODS: Simultaneous recording of scintigraphic solid gastric emptying and gastric clearance of radiopaque markers were conducted in 65 non-ulcer dyspepsia patients. RESULTS: Forty-two patients (64.4%) showed abnormal gastric clearance of radiopaque markers, and 38 patients (58.5%) showed delayed solid gastric emptying. There was no correlation between delayed solid gastric emptying and abnormal gastric clearance of radiopaque markers (p > 0.05). Although the frequency of abnormal gastric clearance of radiopaque markers was higher than that of delayed solid gastric emptying (64.6% versus 58.5%), it was not statistically significant. CONCLUSIONS: On the basis of the results of our study, gastric clearance of radiopaque markers may be used as an easy, non-invasive screening test for the purpose of detecting gastric motor dysfunction. However, this test is not superior to scintigraphic gastric emptying studies.

Adolescent↗

PubMed1996

The effect of Helicobacter pylori infection on gastric emptying of digestible and indigestible solids in patients with nonulcer dyspepsia.

OBJECTIVE: There is no general agreement with regard to the effect of Helicobacter pylori infection on gastric emptying in patients with nonulcer dyspepsia. METHODS: We performed the 14C urea breath test as well as simultaneous recordings of scintigraphic gastic emptying and gastric clearance of radiopaque markers to determine the effect of Helicobacter pylori infection on gastric emptying of digestible and indigestible solids in nonulcer dyspepsia patients. RESULTS: Sixty patients, 30 males and 30 females, were enrolled in the study. There were 22 patients (36.7%) without and 38 patients (63.3%) with H. pylori infection. Twenty-four of the 60 patients (40%) showed normal and 36 patients (60%) showed delayed gastric emptying of digestible solids. In addition, 21 patients (35%) showed normal and 39 patients (63%) showed delayed gastric emptying of indigestible solids. There was no correlation between delayed gastric emptying of digestible and indigestible solids (p > 0.05, difference not significant). Although not statistically significant, the incidence of delayed indigestible solid emptying was higher than that of delayed digestible solid emptying (65% vs. 60%). Among different patterns of gastric emptying, no difference was noted between the patients with and without H. pylori infection. CONCLUSION: Delayed gastric emptying of indigestible solids is as common as delayed gastric emptying of digestible solids in nonulcer dyspepsia patients. The status of H. Pylori infection appeared not to influence the incidence of delayed gastric emptying of digestible and indigestible solids.

Adolescent↗

PubMed1996

[Gastric emptying in non-insulin dependent diabetic patients].

Disordered gastrointestinal motility is an often overlooked clinical problem. Delayed gastric emptying of solid and/or liquid meal in patients with both type 1 and type 2 diabetes mellitus occurs in approximately 50% of these patients. Gastric emptying time (GET) was studied in seventy four non-insulin dependent (type 2) diabetic out-patients by using radionuclide gamma-photography with Tc-99m phytate solid experimental meal. Thirty nine of them received Tc-99m phytate liquid test meal on the next day. Forty six normal healthy volunteers acted as controls. The results showed that solid GET in patients with type 2 diabetes mellitus was significantly delayed (149.44 +/- 64.0 min) as compared with that in the control group (88.7 +/- 14.2 min) (p < 0.001). Fifty three among these 74 diabetic patients had delayed solid GET, accounting for 71.6%. Only 5 of 39 (12.8%) diabetic patients showed delayed liquid GET (average 38.7 +/- 35.3 min; control 46.2 +/- 11.1 min). There were no differences in sugar control, duration of the disease, and upper gastrointestinal symptoms between patients with delayed GET and those with normal GET. We concluded that delayed gastric emptying is very common in patients with non-insulin dependent diabetes mellitus and which has no direct correlation to blood sugar control, duration of the disease, and upper gastrointestinal symptoms. Radionuclide solid gastric emptying test is a both safe (low radioactivity) and convenient (non-invasive) diagnostic tool in non-insulin dependent diabetic gastroparesis.

Adult↗

PubMed1996

Relationship between C14 urea breath test values and solid-phase gastric emptying time in non-ulcer dyspepsia patients.

BACKGROUND: Non-ulcer dyspepsia (NUD) is a poorly understood syndrome often found with endoscopic evidence of gastritis; Helicobacter pylori (Hp) is a common and important cause of gastritis. In the recent literature, gastric hypomotility is thought to be a cause of NUD. Thus, this investigation studied the relationship between Hp and delayed gastric emptying in NUD patients. METHODS: Using a radionuclide-labelled solid meal to calculate gastric emptying time (GET) of 78 NUD patients. The carbon-14 urea breath test (C14 UBT) was used to quantitate Hp infection. RESULTS: The prevalence of Hp infection in patients with NUD reached 59%. There was a strong association of Hp infection with advanced age (p = 0.0091). There was no significant difference between solid-phase GET and C14 UBT values among three different age groups (young, middle, old) of NUD patients. There was no difference among sex, age, body weight and solid-phase GET between Hp-positive and Hp-negative NUD patients. However the solid-phase GET was significantly prolonged in patients with NUD, compared with the controls. CONCLUSIONS: Solid-phase GET is not correlated with the C14 UBT values, and Hp gastric colonization does not account for dyspeptic syndrome in NUD patients.

Adult↗

PubMed1996

Detection of EBV in tumor tissue and peripheral blood by polymerase chain reaction in patients with nasopharyngeal carcinoma.

Sixty-nine untreated patients with a pathologically verified nasopharyngeal carcinoma were selected for the study of detection of EBV in nasopharyngeal tumor and peripheral blood by polymerase chain reaction (PCR). Primers were directed to conserved regions of EBV genome encoding capsid protein gp 220 (Bam HI L region). A distinct 239 bp band of the PCR products indicated the presence of EBV. Results showed that EBV DNA was obtained in 91.3% of 69 NPC patients and 16.7% of 18 healthy individuals on nasopharyngeal tissue, and the difference was statistically significant between the above two groups. Nevertheless, no EBV DNA was verified from the mononuclear cells of the peripheral blood of the two groups. There was no relationship between the positive EBV DNA and the titer of serological markers. Meanwhile, the positive EBV DNA did not show any relationship with the histology type, tumor and nodal bulk, or even metastasis. Although a high positive rate of EBV DNA was detected in nasopharyngeal tumor of patients, additional environmental and genetic factors must still be considered.

Adult↗

PubMed1996

X-ray microanalysis and mapping: measuring uptake and intracellular distribution of labeled molecules.

X-ray microanalysis is a useful technique for elemental analysis of tissues and cells. This technique utilizes x-rays generated in ultra-thin cryosections of tissue by the electron beam in an electron microscope. The x-rays are characteristic of the various elements, and can be used to measure quantitatively the elemental distribution at subcellular levels. An important application of this x-ray microanalysis and mapping technique is the study of uptake and intracellular distribution of molecules containing an element not normally present in the tissue. It is useful for tissues and samples in which the cell population is not homogeneous. Mapping permits elemental distributions to be measured throughout the sample, not just at selected sites. Maps created are not only for the element of interest but also for other specified elements present. Using an x-ray imaging system and cisplatin as a model, we have been able to demonstrate the feasibility of studying the cellular and subcellular distribution of cisplatin, a molecule containing platinum atom.

Animals↗

PubMed1995

Distribution of cisplatin in bone marrow cells: quantitative X-ray imaging.

The distribution of cisplatin in freeze-dried cryosections of rabbit bone marrow cells was measured with an imaging system. Cisplatin contains a single atom of platinum per molecule which allowed the concentration of the drug to be measured throughout the cryosections. This technique was chosen because it does not require the separation of cells into homogeneous subpopulations. X-ray imaging measured not only the distribution of the element labeling the drug, but also other elements which were used to follow the effect of the drug on membrane ion transport. In samples incubated for 10 hr in cisplatin a high selectivity in the uptake of this drug was observed. Only a few of the large early cells were found to accumulate this drug, while in the smaller more mature cells platinum could not be detected. Most of the platinum accumulated in the cytoplasm and was not evenly distributed. Cells containing high levels of platinum lost their cytoplasmic potassium and gained extracellular sodium and chloride. In some cases cells that contain lower concentrations of platinum with normal levels of potassium were found, indicating that the alteration of the membrane permeability or the inhibition of the K/Na pump did not occur during the initial accumulation of the drug. This membrane permeability or pump change requires the accumulation of high concentrations of the drug, resulting in the loss of potassium and the gain of sodium.

Animals↗

PubMed1995

Increased accuracy of the carbon-14 D-xylose breath test in detecting small-intestinal bacterial overgrowth by correction with the gastric emptying rate.

To date, there is no general agreement as to which test is to be preferred for the diagnosis of small-intestinal bacterial overgrowth. The 1-g carbon-14 D-xylose breath test has been proposed as a very sensitive and specific test for the diagnosis of bacterial overgrowth. However, in patients with severe gastrointestinal motor dysfunction, the lack of consistent delivery of 14C-D-xylose to the region of bacterial contamination may result in a "negative" result. The aim of this study was to determine whether the accuracy of 14C-D-xylose breath test for detecting bacterial overgrowth can be increased by correction with the gastric emptying rate of 14C-D-xylose. Ten culture-positive patients and ten culture-negative controls were included in the study. Small-intestinal aspirates for bacteriological culture were obtained endoscopically. A liquid-phase gastric emptying study was performed simultaneously to assess the amount of 14C-D-xylose that entered the small intestine. The results of the percentage of expired 14CO2 at 30 min were corrected with the amount of 14C-D-xylose that entered the small intestine. There were six patients in the culture-positive group with a 14CO2 concentration above the normal limit. Three out of four patients with initially negative results using the uncorrected method proved to be positive after correction. All these three patients had prolonged gastric emptying of 14C-D-xylose. When compared with cultures of small-intestine aspirates, the sensitivity and specificity of the uncorrected 14C-D-xylose breath test were 60% and 90%, respectively. In contrast, the sensitivity and specificity of the corrected 14C-D-xylose breath test improved to 90% and 100%, respectively. In conclusion, using the gastric emptying rate of 14C-D-xylose as a correcting factor, we found a higher sensitivity and specificity for the 14C-D-xylose breath test in the detection of small-intestinal bacterial overgrowth than were achieved with the conventional method.

Adult↗

PubMed1995

The effect of coffee on gastric emptying.

The effect of coffee on gastric emptying was addressed in a scintigraphic liquid-phase gastric emptying study in patients with non-ulcer dyspepsia. Ninety-three subjects (56 males, 37 females; mean age 40 years, range 17-77 years) diagnosed as having non-ulcer dyspepsia were enrolled in the study. The baseline study was to drink 500 ml of 5% glucose water and the coffee study was to drink 500 ml of 5% glucose water containing 4 g of regular instant coffee. The two studies were performed on separate days. Fifteen of the 93 subjects were chosen at random to undergo repeated coffee studies for evaluation of reproducibility. Overall the 93 subjects showed accelerated gastric emptying, as measured by half emptying time (T1/2) with coffee compared with baseline (35.7 +/- 10.5 vs 45.0 +/- 23.1 min, P < 0.001). However, 68 (73.2%) subjects showed accelerated emptying (-14.8 +/- 19.5 min), while 25 (26.8%) subjects showed delayed emptying (5.9 +/- 4.5 min) after ingestion of coffee. There was no significant difference in the change in gastric emptying with coffee in duplicate measurements from the 15 subjects who had two coffee studies (P = 0.082). We conclude that coffee accelerates liquid-phase gastric emptying in the majority of patients with non-ulcer dyspepsia.

Adult↗

PubMed1995

Delayed gastric emptying does not predispose to Helicobacter pylori infection in non-ulcer dyspepsia patients.

Non-ulcer dyspepsia is a common disorder in clinical practice. The pathogenesis and predisposing factors that lead to the development of Helicobacter pylori infection are still unclear. The aim of the present study was to evaluate the prevalence of H. pylori infection in non-ulcer dyspepsia patients with delayed gastric emptying and those with normal gastric emptying, and to determine if delayed gastric emptying predisposes to H. pylori infection. A total of 70 patients (29 males, 41 females) aged 18-59 years (mean +/- S.D. 40.5 +/- 11.2 years) took part in the study. A solid-phase scintigraphic gastric emptying study and 14C urea breath test were performed on each patient. There was no statistically significant difference in age between those patients with and without delayed gastric emptying (40.8 +/- 11.9 vs 40.4 +/- 10.5 years), or between those with and without H. pylori infection (40.5 +/- 12.6 vs 40.5 +/- 9.8 years). Of the 70 patients, 45 (64.3%) had delayed gastric emptying and 25 (35.7%) had normal gastric emptying. The overall incidence of H. pylori infection was 58.6%. The incidence of H. pylori infection among patients with delayed gastric emptying was 60% (27/45 patients) and among patients with normal gastric emptying 56% (14/25) patients). The incidence of H. pylori infection in the two groups was not significantly different. The incidence of H. pylori infection in the non-ulcer dyspepsia patients in this study was similar to that of age-matched asymptomatic volunteers in Taiwan. In conclusion, based on the results of this study, delayed gastric emptying does not lead to a predisposition to H. pylori infection in non-ulcer dyspepsia patients.

Adolescent↗

PubMed1995

Application of ABO genotyping using polymerase chain reaction method to assess engraftment in bone marrow transplantation--a case report.

We described a case of acute promyelocytic leukemia with O blood type who received bone marrow transplantation during a second remission from his HLA identical, B blood type sibling. Using PCR genotyping of the ABO group and analysis of the variable number of tandem repeats of the D1S80 locus, we could quickly document the successful early engraftment in this patient. We emphasize that the use of PCR ABO genotyping is a quick and valuable method which could be applied to assess the engraftment and its follow up in those transplant cases with donors of mismatched blood groups.

ABO Blood-Group System↗

PubMed1995

Clonal analysis in acute myeloid leukemia by polymerase chain reaction.

We have used PCR to amplify a polymorphic portion of the X-chromosome linked phosphoglycerate kinase gene (PGK) combined with a methylation-sensitive restriction enzyme digestion of the active X chromosome to examine the frequency of heterozygosity in Taiwanese females and analyze clonality in 18 female patients with acute myeloid leukemia (AML). We used hair follicles as normal tissue control. We found that the incidence of heterozygosity of the PGK gene in 102 hematological normal females and 18 patients tested was 35% (42/120). In five AML patients, a monoclonal X-inactivation pattern of leukemic blasts was found at presentation, which then returned to polyclonal at remission. In two of these five cases, a monoclonal pattern recurred at relapse. We also found that the hair follicles were readily accessible normal tissue for control, were easy to obtain, and were non-invasive.

Base Sequence↗

PubMed1995

MDR1 gene expression in acute myeloid leukemia: clinical correlation.

Acute myeloid leukemia (AML) has a poor long-term prognosis, with a disease-free survival rate of only 20%. Drug resistance remains the major obstacle in this disease, although relatively little data are available on the correlation of multi-drug resistance (MDR) and clinical outcome. We examined 28 bone marrow samples from 24 patients with AML. The MDR1 RNA levels were determined by slot blot analysis. The incidence of positive expression of MDR1 mRNA in patients was 64.7% in samples from newly-diagnosed patients and 85.7% in relapse samples. The overall complete remission rate was 45%. However, the complete remission rate was lower for patients in the MDR1 RNA positive group than in the negative group. In three cases, the MDR1 RNA expression steadily rose during the period of disease progression and after several courses of chemotherapy. We suggest that a high frequency of MDR1 gene expression in patients with AML and higher MDR1 RNA levels are associated with a lower incidence of complete remission as well as a shorter disease-free time. The expression of MDR1 is a poor prognostic factor for AML treatment and it may play an important role in resistance to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗