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Biomedical subjects

H R Guo

Publications and source records attributed to H R Guo.

At least 19 recordsLinked to original sources
PubMed2005

Klebsiella pneumoniae fascial space infections of the head and neck in Taiwan: emphasis on diabetic patients and repetitive infections.

OBJECTIVES: To assess the epidemiological features, clinical characteristics, treatment, and outcome of head and neck infections caused by Klebsiella pneumoniae. METHODS: We reviewed records of four common aerobic pathogens isolated by the microbiological laboratory of a teaching hospital in Taiwan from July 1995 to December 1999. Patients aged 14 or older with community-acquired fascial space infections of head and neck were identified by review of medical records and included in the study. RESULTS: A total of 100 cases were identified, and K. pneumoniae was the most common pathogen of monomicrobial infections (48%), followed by viridans streptococci (15%). Polymicrobial infections were noted in 35 cases. In comparison with patients with infections not caused by K. pneumoniae, those with monomicrobial K. pneumoniae infections were older (P = 0.04) and had a higher prevalence of diabetes mellitus (P < 0.001), a longer duration of antimicrobial therapy (P = 0.007), a longer hospital stay (P = 0.001), and more repetitive infections (P = 0.001). All but one of K. pneumoniae isolates were susceptible to first generation cephalosporins and aminoglycosides. CONCLUSIONS: K. pneumoniae is an important endemic pathogen of fascial space infections of head and neck in Taiwan, especially among diabetics. Physicians should be aware of the tendency of this organism to cause repetitive infection.

Adult↗
PubMed2001

Functional mutation in the promoter region of thrombomodulin gene in relation to carotid atherosclerosis.

Thrombomodulin is an important endothelial anticoagulant protein that decreases thrombin activity and activates protein C. Our recent study has shown that the G-33A promoter mutation of thrombomodulin gene is associated with coronary artery disease. This study was conducted to determine whether the G-33A mutation in the promoter region of thrombomodulin gene is a genetic risk factor for ischemic stroke or carotid atherosclerosis. The functional significance of this mutation was also evaluated. We recruited 333 patients (mean age 64 years, 59% male) with ischemic stroke and 257 age- and sex-matched controls. In all study participants, carotid atherosclerosis was assessed by Duplex scanning, and thrombomodulin G-33A promoter mutation was detected by single-strand conformation polymorphism. Luciferase reporter gene assay was used to assess the influence of this mutation on thrombomodulin promoter activity. There was no significant difference in the thrombomodulin G-33A mutation frequency (GA+AA genotypes) between the stroke and the control groups (18.3 vs. 24. 1%, P=0.105). The G-33A mutation frequency was also similar between the study participants with and without carotid atherosclerosis (22.2 vs. 19.8%, P=0.550). When only younger subjects (age </=60 years) were included in the analysis, however, we found the mutation occurred more frequently in participants with carotid atherosclerosis (33.3 vs. 17.3%, odds ratio [OR]=2.38, 95% confidence interval [CI]=1.16-4.90, P=0.027). Multiple logistic regression analyses showed that only diabetes mellitus (OR=3.11, 95% CI=1.33-7.30, P=0.009) and G-33A mutation (OR=2.46, 95% CI=1.14-5.29, P=0.021) were associated independently with carotid atherosclerosis in younger subjects. As assessed by luciferase reporter gene assays, the contructs bearing the G-33A mutation showed a significant decrease (36+/-12%) in transcriptional activity in comparison with the wild type constructs. Our findings suggest that G-33A mutation reduces the thrombomodulin promoter activity and is associated with carotid atherosclerosis in younger subjects.

Aged↗
PubMed2001

Magnetic-activated cell sorting (MACS) significantly decreases the hybridization efficiency of fluorescence in situ hybridization (FISH).

Fetal cells were enriched from maternal blood using density gradient centrifugation of Histopaque followed by magnetic-activated cell sorting (MACS) to select CD71-positive cells. For each specimen, cells partially purified by Histopaque were split into equal portions, and each portion was subjected to purification by MACS in parallel. Cells before and after MACS were subjected to dual-color fluorescence in situ hybridization (FISH) analysis with X- and Y-chromosome-specific probes. We found that the hybridization rates were decreased by approximately 10% after MACS based on duplicated analysis for each sample.

Adult↗
PubMed2001

Arsenic in drinking water and skin cancers: cell-type specificity (Taiwan, ROC).

OBJECTIVE: The association between arsenic ingestion and cancer has been documented for more than a century. Previous studies showed that the carcinogenic effects of arsenic on the urinary system are cell-type specific. To evaluate whether this is also true for skin cancers, we conducted an ecological study in 243 townships in Taiwan. METHODS: The arsenic exposure was assessed on the basis of measurement reports from a previous survey, and cases of skin cancer were identified using the information gathered by the National Cancer Registry Program. We analyzed the data by regression models using multiple variables to describe the exposure status, and an urbanization index was also included in the models to adjust for the effects of urbanization. RESULTS: A total of 2369 patients with skin cancer, comprising 1415 men and 954 women, were registered between 1 January 1980 and 31 December 1989. Among the three major cell types of skin cancer, squamous cell carcinoma and basal cell carcinoma appear to be associated with ingestion of arsenic. Such an association was not observed for malignant melanoma. CONCLUSIONS: The results suggested that the carcinogenicity of arsenic on skin is cell-type specific, which is compatible with the findings in previous studies on urinary cancers.

Adult↗
PubMed2001

Factors associated with discontinuing insulin therapy after diabetic ketoacidosis in adult diabetic patients.

AIMS: To assess the factors associated with successful discontinuation of insulin therapy after diabetic ketoacidosis (DKA) in adult patients. METHODS: Patients (>or= 18 years) attending the Endocrine and Metabolism Clinic at a major hospital in southern Taiwan were recruited. After recovery from the acute stage, those with no contraindications to oral antidiabetic agents, with adequate beta cell reserve, and with no antiglutamic acid decarboxylase (GAD) antibody were treated with oral agents. RESULTS: Sixty-six patients (38 males, 28 females, aged 18-76 years) were included, and 21 qualified for treatment with oral agents. These 21 patients were older at diagnosis of diabetes (45.5 +/- 14.0 vs. 40.0 +/- 13.8 years, P = 0.047), had shorter diabetes duration (median 0 vs. 5.5 months, P = 0.040), higher BMI (median 23.4 vs. 19.5 kg/m2, P < 0.001), higher serum osmolality during DKA (352.1 +/- 40.7 vs. 318.0 +/- 16.4 mmol/kg, P = 0.005), and lower insulin dose following recovery (median 0.49 vs. 0.83 unit/kg/d, P < 0.001) than those patients that had to continue insulin therapy. Thirteen patients (8 males, 5 females; 62%) successfully discontinued insulin for at least one year without recurrence of DKA. Multiple logistic regression analyses showed that BMI >or= 25 kg/m2 (adjusted relative risk (ARR) 8.85, 95% CI 1.05, 8.39), diabetes onset age >or= 40 years (ARR 8.08, 95% CI 1.16, 6.95), and undiagnosed diabetes before DKA (ARR 8.90, 95% CI 1.19, 7.51) were significant factors associated with successful discontinuation of insulin therapy. CONCLUSION: We identified three independent clinical factors associated with successful discontinuation of insulin therapy after DKA.

Adolescent↗
PubMed2000

G-33A mutation in the promoter region of thrombomodulin gene and its association with coronary artery disease and plasma soluble thrombomodulin levels.

Thrombomodulin is an endothelial glycoprotein that decreases thrombin activity and activates protein C. A recent study has shown that G-33A promoter mutation of the thrombomodulin gene occurs particularly in Asians. In this study, we analyzed the distribution of G-33A mutation in the promoter region of the thrombomodulin gene in the Chinese population and determined whether the mutation might be a risk for coronary artery disease (CAD). In addition, the influence of this mutation on plasma soluble thrombomodulin levels in patients with CAD was also examined. We studied 320 consecutive patients (mean age 63 years; 73% men) with CAD and 200 age- and sex-matched control subjects. Screening for thrombomodulin G-33A promoter mutation was conducted using polymerase chain reaction, single-strand conformation polymorphism, and direct deoxyribonucleic acid sequencing. The frequency of the G-33A mutation (GA+AA genotypes) was significantly higher in the CAD group (23.8% vs 15.5%, odds ratio [OR] 1.70, p = 0.031). Multiple logistic regression analysis showed that the mutation was an independent risk factor (OR 1.81, p = 0.016) for CAD, as was hypertension (OR 1.44, p = 0.040), diabetes mellitus (OR 2.50, p <0.001), and smoking (OR 2.15, p <0.001). In CAD patients with GG genotype, the soluble thrombomodulin level increased with the extent of CAD (36 +/- 15 vs 47 +/- 18 vs 55 +/- 36 ng/ml in 1-, 2-, or 3-vessel CAD, p <0.001). However, in CAD patients with G-33A mutation, there was no difference between the levels of soluble thrombomodulin (39 +/- 17 vs 37 +/- 15 vs 42 +/- 18 ng/ml, p = NS) in 1-, 2-, or 3-vessel CAD. Our observations suggest that there is a significant association of the G-33A mutation in thrombomodulin gene with CAD, and this mutation may influence the soluble thrombomodulin levels in patients with CAD.

Asian People↗
PubMed2000

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↗
PubMed1999

Nucleated red blood cells in maternal blood during pregnancy.

OBJECTIVE: To assess the frequencies of nucleated red blood cells (RBCs) in maternal blood during different stages of gestation and postpartum. METHODS: Peripheral venous blood samples were collected longitudinally from 38 pregnant women from the first trimester to 3 months postpartum. Nucleated RBCs were isolated by using a triple-density gradient with Histopaque (Sigma Diagnostics, St. Louis, MO) and identified by Kleihauser-Betke acid stain. RESULTS: The number of nucleated RBCs steadily increased from 3.9 (standard error 0.6) per 10(7) nucleated cells in early gestation (6-10 weeks) to 112.0 (standard error 7.5) per 10(7) nucleated cells near term and decreased rapidly after delivery. The number of nucleated RBCs was not related to the gender of the fetus or the ABO blood type compatibility between the mother and fetus. CONCLUSION: The number of nucleated RBCs in the maternal blood increase progressively throughout pregnancy, with some variation from subject to subject.

Adult↗
PubMed1999

Prognostic significance of elevated hemostatic markers in patients with acute myocardial infarction.

OBJECTIVES: The purpose of this study was to determine whether the elevated levels of hemostatic markers in the early phase of myocardial infarction may serve as risk factors for subsequent cardiac mortality. BACKGROUND: Increased plasma hemostatic markers were noted in acute myocardial infarction, indicating that the blood coagulation system is highly activated in those patients. However, there are few clinical data concerning the association between the elevated hemostatic markers and survival in patients with myocardial infarction. METHODS: Blood samples were obtained from 64 patients (mean age 67 +/- 11 years; 49 male) with acute myocardial infarction within 12 h after the onset of symptoms and before the initiation of any antithrombotic treatment. We measured plasma concentrations of fibrinopeptide A (FPA), prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complex (TAT) using the enzyme-linked immunosorbent assay method, and examined the associations between the level of these markers and survival with Cox proportional hazards models. RESULTS: The follow-up time was 27 +/- 17 months, and 19 patients died of cardiac causes during the follow-up. Univariate survival analysis identified Killip class IV (hazard ratio 4.86; 95% confidence interval [CI] 1.55-15.19), left ventricular ejection fraction (hazard ratio 0.94; 95% CI 0.90-0.99), FPA (hazard ratio 1.54; 95% CI 1.13-2.10), F1+2 (hazard ratio 2.03; 95% CI 1.17-3.53) and TAT (hazard ratio 1.88; 95% CI 1.27-2.79) as significant factors associated with cardiac mortality. In multivariate analyses, only FPA level (hazard ratio 1.84; 95% CI 1.03-3.30) and left ventricular ejection fraction (hazard ratio 0.93; 95% CI 0.88-0.98) were independent predictors of cardiac mortality. CONCLUSIONS: Elevated FPA in the early phase of myocardial infarction identifies patients with increased risk for subsequent cardiac death. This association appears to be independent of residual left ventricular function after infarction.

Adult↗
PubMed1999

Back pain prevalence in US industry and estimates of lost workdays.

OBJECTIVES: Back pain is the most common reason for filing workers' compensation claims and often causes lost workdays. Data from the 1988 National Health Interview Survey were analyzed to identify high-risk industries and to estimate the prevalence of work-related back pain and number of workdays lost. METHODS: Analyses included 30074 respondents who worked during the 12 months before the interview. A case patient was defined as a respondent who had back pain every day for a week or more during that period. RESULTS: The prevalence of lost-workday back pain was 4.6%, and individuals with work-related cases lost 101.8 million workdays owing to back pain. Male and female case patients lost about the same number of workdays. Industries in high-risk categories were also identified for future research and intervention, including those seldom studied. CONCLUSIONS: This study provides statistically reliable national estimates of the prevalence of back pain among workers and the enormous effect of this condition on American industry in terms of lost workdays.

Adult↗
PubMed1998

Using ecological data to estimate a regression model for individual data: the association between arsenic in drinking water and incidence of skin cancer.

In ecologic studies, participants are studied by groups, and the exposure status of each group is usually represented by a single indicator, mostly the mean exposure. In this paper, we propose using multiple variables derived from dummy variables at the individual level to describe the exposure. An analysis of the association between arsenic in drinking water and skin cancer was used as an example. Well water arsenic levels and skin cancer incidence from 1980 to 1987 were assessed for 243 townships in Taiwan. We first analyzed the data using the mean arsenic concentration in each township as the only exposure variable. The second analysis used multiple variables to describe arsenic exposure; each variable denoted the percentage of wells with arsenic levels within a specific range in each township. Although the first approach did not identify associations between arsenic levels and skin cancer, the multiple-variable approach identifies a positive association at the highest arsenic exposure category (>0.64 mg/L) in both men and women. Therefore, using multiple variables to describe an exposure in ecologic studies may facilitate a better description of the exposure status and thereby lead to more accurate risk assessment, especially when the dose-response relationship is not linear.

Arsenic↗
PubMed1998

Prevalence of Coxiella burnetii infections among North Dakota sheep producers.

A case of Q fever in a sheep producer was detected by a surveillance system in North Dakota in 1993, when Q fever was not reportable. This is the first officially documented case in the state. To estimate the prevalence of Coxiella burnetii infection and identify associated risk factors, we conducted a study covering the whole state. A total of 17 cases were identified among 496 sheep producers, their family members, and hired helpers. The number of sheep raised was a good predictor of C. burnetii infection. Lambing outdoors and frequent physical contacts with sheep during lambing were associated with a higher risk, but petting dogs was correlated with a lower risk. We conclude that C. burnetii infection is prevalent among sheep producers in North Dakota. As the result, Q fever became a reportable disease in North Dakota.

Adult↗
PubMed1997

Clinicopathological features of bladder cancer associated with chronic exposure to arsenic.

A high incidence of bladder cancer has been documented in an area of chronic arsenic (As) exposure. This study investigates the characteristics of As-associated (n = 49) and other (n = 64) bladder cancers. A higher histological grading was observed for the As-exposed tumours (P = 0.04), but no other difference in pathobiological features or prognosis was found between the two groups.

Aged↗
PubMed1997

Arsenic in drinking water and incidence of urinary cancers.

The associations between arsenic ingestion and cancers of the bladder and kidney have been documented in Taiwan. To evaluate further such associations for urinary cancers of various cell types, we conducted an ecologic study encompassing 243 townships using cancer registry data of patients diagnosed between 1980 and 1987. We used the proportions of wells with various specified arsenic levels in each township as indicators of exposure and evaluated the effects of urbanization and smoking by an urbanization index and the number of cigarettes sold per capita. In both genders, we observed associations of high arsenic levels in drinking water with transitional cell carcinomas of the bladder, kidney, and ureter and all urethral cancers combined. We also observed such associations in adenocarcinomas of the bladder in males, but not in squamous cell carcinomas of the bladder or renal cell carcinomas or nephroblastomas of the kidney. There was also a positive association between the urbanization index and transitional cell carcinomas of the ureter in males. The number of cigarettes sold per capita was not a good predictor for urinary cancers. The results indicate that the carcinogenicity of arsenic may be cell type specific.

Adolescent↗
PubMed1997

Skin cancer and inorganic arsenic: uncertainty-status of risk.

The current U.S. EPA standard for inorganic arsenic in drinking water is 50 ppb (microgram/L), dating to the National Interim Primary Drinking Water Regulation of 1976. The current EPA risk analysis predicts an increased lifetime skin cancer risk on the order of 3 or 4 per 1000 from chronic exposure at that concentration. Revision of the standard to only a few ppb, perhaps even less than 1 ppb, may be indicated by the EPA analysis to reduce the lifetime risk to an acceptable level. The cost to water utilities, and ultimately to their consumers, to conform to such a large reduction in the standard could easily reach several billion dollars, so it is particularly important to assess accurately the current risk and the risk reduction that would be achieved by a lower standard. This article addresses the major sources of uncertainty in the EPA analysis with respect to this objective. Specifically, it focuses on uncertainty and variability in the exposure estimates for the landmark study of Tseng and colleagues in Taiwan, analyzed using a reconstruction of the their exposure data. It is concluded that while the available dataset is suitable to establish the hazard of skin cancer, it is too highly summarized for reliable dose-response assessment. A new epidemiologic study is needed, designed for the requirements of dose-response assessment.

Arsenic↗
PubMed1996

Is ingested inorganic arsenic a "threshold" carcinogen?

Ingested inorganic arsenic (As) is known to be a human carcinogen. An intriguing question is whether there is a threshold for the carcinogenic effects of As, i.e., is there a level below which it does not induce the development of cancer(s)? This Roundtable will discuss the United States Environmental Protection Agency's As risk assessment using the Taiwan data from different viewpoints. It will also consider the hypothesis that there is a threshold for As and data for or against this hypothesis. For example, some scientists believe that epidemiological data cannot answer this question, while others feel that different study designs and larger sampling will provide adequate data. Reasons for each position are given. This Roundtable discussion demonstrates the controversy surrounding the use of the Taiwan data for risk assessment.

Arsenic Poisoning↗
PubMed1995

Back pain among workers in the United States: national estimates and workers at high risk.

Back pain accounts for about one fourth of workers' compensation claims in the United States. The Occupational Health Supplement to the 1988 National Health Interview Survey provided an opportunity to assess the scope of this problem. The 30,074 respondents who worked in the 12 months before the interview were defined as "workers", and those with back pain every day for a week or more during that period were defined as "cases." A weighting factor was applied to the answers to derive national estimates. In 1988, about 22.4 million back pain cases (prevalence 17.6%) were responsible for 149.1 million lost workdays; 65% of cases were attributable to occupational activities. For back pain attributed to activities at work, the risk was highest for construction laborers among males (prevalence 22.6%) and nursing aides among females (18.8%). Our analyses show that back pain is a major cause of morbidity and lost production for U.S. workers and identifies previously unrecognized high risk occupations, such as carpenters, automobile mechanics, maids, janitors, and hairdressers, for future research and prevention.

Adult↗