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Biomedical subjects

S C Hu

Publications and source records attributed to S C Hu.

At least 19 recordsLinked to original sources
PubMed1992

Simulation of ozone uptake distribution in the human airways by orthogonal collocation on finite elements.

Ozone transport in a rigid single-pathway anatomic model of the lung was analyzed by a stable convergent numerical algorithm, the method of orthogonal collocation on finite elements. The simulations predicted the dynamic behavior of gas phase concentration profiles for both ozone and an insoluble inert gas. An internal quasi-stationary diffusion front was observed during early inspiration for both gases. In addition, the absorptive distribution of ozone in lung airways was computed as a total dose as well as a tissue dose. The total dose of ozone decreased along the airway path from the mouth. However, the tissue dose of ozone increased along the conducting airways, reached a maximal dose in the terminal bronchioles, and decreased sharply in the respiratory airways.

Algorithms↗
PubMed1992

Longitudinal distribution of ozone absorption in the lung: quiet respiration in healthy subjects.

The objective of this research was to develop a bolus-response method for the noninvasive determination of O3 distribution in the human lung. A previously developed O3 analyzer and bolus generator were incorporated in a computer-controlled inhalation system, and measurements of O3 absorption from inhaled 10-ml boluses with a peak O3 concentration of 4 ppm were carried out on nine previously unexposed healthy male subjects engaged in quiet oral breathing. The fraction of O3 absorbed during a single breath was measured over a range of airway penetrations from 20 to 200 ml, with inspiratory and expiratory flows fixed at a nominal value of 250 ml/s. The resulting data indicated that 50% of the inhaled O3 was absorbed at a penetration of 70 ml, which roughly corresponds to the upper airways, and essentially complete absorption occurred at a penetration of 180 ml, which roughly corresponds to the 16th airway generation, the beginning of the proximal alveolar region. This compares favorably with the results of direct-sampling methods, which indicated that 40.4% of continuously inhaled O3 is removed by the extrathoracic airways (Gerrity et al. J. Appl. Physiol. 65: 393-400, 1988). The computation of an absorption rate constant, Ka, revealed that the efficiency of O3 uptake increased with longitudinal position throughout most of the conducting airways but began to fall off at a penetration of 160 ml.

Absorption↗
PubMed1992

Endoscopy for upper gastrointestinal bleeding at emergency unit.

From November 1, 1990 to January 31, 1991, 381 patients visited our emergency unit with the chief complaints of hematemesis (n = 153) and melena (n = 228). Of these patients, 298 (78.2%) received UGI endoscopy at the emergency unit, 29 (7.6%) received examination after they were admitted to wards, 3 (0.8%) received endoscopy at outpatient clinic and 51 (13.4%) did not have endoscopy. The percentages of endoscopic diagnoses in 330 patients who had UGI endoscopy were gastric ulcer (GU) 33.6%, duodenal ulcer (DU) 32.7%, esophageal varices (EV) 17.0%, and others 15.5%. Negative findings were noted in 3 cases and no definite bleeding source was found in 1 patient who had blood retention in stomach. The diagnostic rate of endoscopy was 98.8%. Of the 56 patients with EV, 45 (80.4%) had hematemesis; in contrast, 85 of the 108 DU patients (78.8%) complained of melena only. Of the 219 patients with bleeding GU/DU, 64 (29.2%) had endoscopic therapies and 7 (3.2%) needed operation. Sixty-four (29.2%) of them received UGI endoscopy within 6 hours after arrival. They had significantly higher frequency of stigmata of recent hemorrhage (SRH) and more endoscopic therapies than the remaining patients. The overall mortality rate in our patients was 6.0%; the mortality rate in patients with EV was much higher than that of the patients with GU/DU (19.6% vs. 1.8%, P less than 0.001). Of the 23 expired cases, only 11 died of hypovolemic shock. The remaining 12 patients died of deterioration or complications of their underlying diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Flumazenil as an emergency management of patients with acute mental disorder].

From July 1, 1990 to June 30, 1991, 55 adult patients with acute alteration of mental status of unknown etiology were enrolled into this study in order to evaluate the diagnostic and therapeutic role of flumazenil in the management of this disorder. Patients who were pregnant or had severe head injury, hemodynamic instability or a provisional diagnosis of hypoglycemia, meningitis or acute cerebrovascular event were excluded. Flumazenil was injected intravenously first in a regimen of 0.3 mg followed by alternative 0.2 mg and 0.3 mg doses every minute until a total dose of 1 mg was given or until the patients responded. These patients were divided into 2 groups based on their response to flumazenil: Group 1, responders (N = 26) and Group 2, nonresponders (N = 29). Good response in Group 1 allowed the cancellation or discontinuation of brain CT scan in 18 patients; intubation and artificial ventilation in 2 and vasopressor infusion in one. The hospital stay was shortened significantly as compared with historical information in uncomplicated benzodiazepine intoxication patients who were admitted before flumazenil was introduced. The Group 2 patients who were with a great span of levels of severity in clinical courses, had higher admission and mortality rate than Group 1 (p < 0.01). We concluded that flumazenil may serve as a useful tool in the diagnosis and management of carefully selected patients. The use of flumazenil with our selective criteria will be cost effective, achieve rapid diagnosis and reduce laborious care in certain cases.

Acute Disease↗
PubMed1991

Inhibition of the delayed-type hypersensitivity response by staphylococcal enterotoxin B-induced suppressor T cells.

Staphylococcal enterotoxin B (SEB) is a member of a family of gram-positive bacterial exotoxins which act as superantigens in both mouse and man. The administration of this toxin has been shown to inhibit antibody responses in vivo. We have previously shown that SEB is a potent inducer in vitro of multiple T suppressor cell populations. The present studies show that administration of microgram quantities of this toxin result in a reduced capacity to manifest a delayed-type hypersensitivity (DTH) response. In addition, we find that the failure to generate a normal DTH response appears to be due to the generation of a T suppressor cell population following SEB administration. Adoptive transfer studies show that the suppressor cells bear the CD5+ I-J+ CD4- CD8- Thy 1+ surface phenotype. The relationship of these cells to suppressor T cell populations generated following in vitro activation by SEB is discussed.

Animals↗
PubMed1991

Ozone absorption into excised porcine and sheep tracheae by a bolus-response method.

The absorption of ozone (O3) into excised porcine and sheep tracheae was characterized by a bolus-response experiment in which a bolus with a peak O3 concentration of 1 ppm was rapidly injected into a steadily flowing airstream entering the trachea. Using a fast-responding chemiluminescent analyzer of our design, the O3 concentration curves at the proximal end (i.e., the bolus input) and at the distal end (i.e., the response) of the trachea were monitored. Each concentration curve was numerically integrated, and the fraction of O3 absorbed in the trachea was obtained by subtracting from unity the ratio of the response integral to the bolus input integral. Average values of ozone-absorbed fraction decreased from about 0.50 to 0.15 at increasing airflows from 50 to 200 ml/sec. A diffusion theory that includes the effects of bulk convection, axial dispersion, and first-order absorption was developed to relate the fractional absorption to an overall mass transfer coefficient (K). The results indicate that K is independent of airflow, suggesting that the diffusion resistance in mucus is much greater than that in the gas phase. The time-weighted integrals of the concentration curves were also computed, allowing the mean residence time of O3 in the trachea (delta tau) to be determined. As predicted by the diffusion theory, delta tau was inversely related to the rate of O3 absorption.

Absorption↗
PubMed1991

Ultrasonography to diagnose and exclude intussusception in Henoch-Schönlein purpura.

Abdominal pain is a frequent symptom in the child with Henoch-Schönlein purpura and raises the suspicion of intussusception or perforation. One hundred and fifty two children with a diagnosis of Henoch-Schönlein purpura over 11 years were reviewed. Of these 60 had abdominal pain, 19 gastrointestinal bleeding, and nine were suspected intussusception. Intussusception was confirmed in two of these cases with ultrasonography. Ultrasound is an important tool in the early diagnosis of intussusception complicating Henoch-Schönlein purpura. Where the intussusception appears loose an expectant policy, with careful monitoring, may allow spontaneous reduction. It may also be used in monitoring patients for postoperative recurrence of intussusception, mural haematoma, and uncomplicated intestinal vasculitis with oedema.

Child↗
PubMed1991

Attachment of influenza A virus to ferret tracheal epithelium at different maturational stages.

Influenza virus attaches primarily to ciliated cells in mature airways epithelium. This process is mediated by a viral envelope glycoprotein (hemagglutinin) that binds to sialic acid-containing receptors in the apical membrane of host cells. The purpose of this study was to determine the cellular distribution of these receptors as a function of tracheal epithelial maturation in the ferret, which is susceptible to influenza virus infection at all ages and undergoes postnatal ciliation. To assay for virus attachment, tracheal strips from ferrets at ages 0, 7, 14, and 28 d were incubated at 4 degrees C for 1 h with a concentrated suspension of influenza A virus. Transmission electron microscopy demonstrated virus attachment to the apical surface of 77 to 87% of ciliated cells, but only to 1 to 9% of nonciliated surface epithelial cells at all ages, including the newborn, which has few ciliated cells (less than 10% of total cells). Virions also attached to most of the preciliated cells identified. Pretreatment of tracheal strips with neuraminidase virtually eliminated viral attachment. These findings demonstrate preferential influenza virus binding to sialylated receptors on ciliated cells and their immediate precursors. The sparsity of ciliated cells with no evidence for increased influenza virus binding per cell in newborn ferret tracheas suggests that the previously demonstrated high risk of death from influenza infection in newborn ferrets is due to factors other than increased susceptibility to virus attachment. Influenza virus receptors appear to be selective membrane markers for ciliated cells and may be particularly useful for the identification of preciliated cells.

Animals↗
PubMed1991

A study on the pre-admission characteristics of patients with acute myocardial infarction.

To clarify an appropriate policy to implement Emergency Medical Services (EMS) in Taiwan based on the profiles of patients with acute myocardial infarction (AMI), and to compare the differences of clinical features accompanied by AMI between Orientals and Westerners, 63 consecutive patients with definite AMI entering the emergency room (ER) from September 1989 through January 1990 were studied. Several interesting facts were found: 1) 9.5% (6/63) of patients took public ambulance to seek medical help; 2) 89% came from out of our jurisdiction, and 62% (39/63) were referred from general practitioners or the ER of community hospitals; 3) There were 5 truly delayed cases (7.9%) owing to a lack of sense of danger in case of chest pain; 4) 50% of our cases occurred during sleeping; 5) The time of onset peaked from 0 AM to 6 AM; 6) While 63.5% of patients visited ER within 6 hours after the onset of acute symptoms, only 12.7% were treated with thrombolytic therapy; and 7) AMI patients stayed in ER for an average of over 4 hours. With limited cases, although trends were evident, firm conclusions were not warranted. The following crucial recommendations are suggested: 1) EMS system in terms of caring of AMI patients still needs a well-designed study to map out an appropriate policy; 2) The strengthening education to physicians working in ER or to all primary care physicians of an early use of thrombolytic agents in indicated cases should be warranted to offer timely therapy when necessary; 3) General public should be educated to call for medical help as soon as possible in case of chest pain.

Ambulances↗
PubMed1991

Clinical and demographic characteristics of 13,911 medical emergency patients.

In order to provide better quality of care at Taipei Veterans General Hospital, 13,911 emergency patients coming into the medical emergency room were studied using the computer to key in all demographic data including registration time, time to be seen, desposition time, impression, triage category, discipline as well as daily dynamic status in the observation room from August through December 1989. The study showed that 8.6% were triage category 1 (life-threatening cases) and 22.08% were triage 4 (pseudo-emergency patients). Of the average 101 studied patients seen per day, 20 (20.27%) should have been theoretically admitted, but only 14.7% were admitted, and 18 (18.08%) were sent to the observation room. In general, the daily dynamic status of the patients in the observation room were: (1) Out of 45 overnight patients, 12 (27%) were waiting for admission; and (2) 9 (20.14%) were waiting for a transfer to other convalescent hospitals. We conclude that less than one-tenth of the emergency patients were really emergencies in such a large and busy emergency department, and there was enormous patients stasis in the observation room causing overcrowding of the emergency department, which is the main issue we have to resolve if the quality assurance of the emergency department is to be improved.

Computers↗
PubMed1991

Neurotoxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in the substantia nigra and the locus coeruleus in BALB/c mice.

The purpose of the present study was to determine whether 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), administered systemically or as a local infusion, has a direct neurotoxic action upon dopamine (DA) neurons in the substantia nigra (SN) and norepinephrine (NE) neurons in the locus coeruleus (LC) in BALB/c mice. Results indicated that both acute and repeated MPTP infusions (2 micrograms/0.3 microliter per side) significantly impaired locomotor activity, decreased stereotyped behavior and caused a disturbed pattern of locomotion in mice. The biochemical changes parallel the behavioral changes. Repeated MPTP infusions to the SN decreased DA levels markedly in the SN and the striatum; chronic MPTP infusions to the LC reduced NE levels markedly in the LC and the hippocampus. Furthermore, repeated MPTP injections for 7 days (30 mg/kg, one injection per day) have resulted in a long-lasting effect on both the nigral-striatal and the coeruleus-hippocampal systems. DA levels in the SN and the striatum were decreased at 1, 3, 7 and 28 days after the last MPTP injection. Similarly, NE levels in the LC and the hippocampus were also reduced markedly at the same time intervals examined. Behaviorally, repeated MPTP treatment also produced long-lasting motor deficits in mice at all time intervals studied. Moreover, the LC appeared to be more sensitive than the SN to the neurotoxic effects of MPTP. Immunohistochemical results have similarly revealed that repeated MPTP treatment markedly decreased tyrosine hydroxylase-positive cells and fibers in the SN and the LC. It also markedly decreased DA-beta-hydroxylase-positive cells and fibers in the LC.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1991

[Synthesis and antimicrobial activity of 7-acylamido-3-1, 2, 3-triazol-1-ylmethyl) cephalosporins].

In order to develop oral cephalosporin exhibiting broad-spectrum activity, a series of cephalosporin derivatives (VIII1-12) bearing 1, 2, 3-triazolymethyl substituents on the C3 position were synthesized. 7-Phenylacetamido-3-methyl-3-cephem-4-carboxylic acid (I) was employed as starting material and converted to VIII by procedures of esterification and oxidation, bromination, azido-substitution, dipolarcycloaddition, deprotection, cleavage, and condensation. Minimum inhibitory concentration (MIC) values in vitro showed that VIII2-4.9-11 had a wide antibacterial spectrum against Gram positive and Gram negative bacteria and possessed high activities. Further biological evaluation and the study of oral absorption for the six compounds will be performed.

Cephalosporins↗
PubMed1990

[Survey of Enterobius vermicularis infection among school children in Tainan City].

A survey was conducted for enterobiasis, in six primary schools at Tainan city. The survey was conducted in 1986, involving 8,120 school children. The manner of testing, was two consecutive day, adhesive cellophane paper perianal swabs. The test resulted in general infection rate of 30.4%. The positive rates among those primary school children were significantly different (chi 2-test, p less than 0.001). The highest rate (40.3%), was in Shih-Men primary school and the lowest rate (18.7%) in Pao-Jeng primary school. Gender occurrence of enterobiasis was determined by making a statistic analysis between sex. We found significantly higher occurrence in males (32.4%) as opposed to females (28.3%) (chi 2-test, p less than 0.001). The infection rates were also significantly different by grade (chi 2-test, p less than 0.001). The highest rate was found in the lower grades (35.3%), the next in the middle grades (32.4%), and the lowest in the higher grades (21.6%). A questionnaire demonstrated that the family status and personal hygiene are the most important factors in transmission of pinworm infection, among the group surveyed. Moreover, the educational levels, occupations of parents, and facilities of bathrooms, (between both primary schools) were also found significantly associated with the transmission of pinworm infection. Therefore, we believe that these factors play a role in transmission of pinworm infection among school children.

Age Factors↗
PubMed1989

Immunomodulatory activity of staphylococcal enterotoxin-B. The induction of an I-J-restricted suppressor factor.

Staphylococcal enterotoxin-B (SEB), a common cause of food-borne intoxication, is a potent polyclonal T cell activator. Previous studies from this laboratory and others have shown that SEB has the capacity to nonspecifically inhibit antibody responses both in vivo and in vitro. We have shown that the inhibitory activity of SEB is mediated, in part, by the activation of a CD8+, CD4-, and CD5- suppressor cell population. The present studies show that the activity of the SEB-induced suppressor cell population is mediated by a soluble factor. This factor nonspecifically inhibits both primary and secondary in vitro antibody responses. Delayed addition analysis demonstrates that the factor must be present early in the ongoing antibody response to exhibit suppressive activity. Monoclonal anti-I-J antisera block the activity of the factor, and eluates (but not filtrates) collected from monoclonal anti-I-J immunoaffinity columns possess suppressive activity. Furthermore, the activity is restricted at the "I-J" gene locus, but is not restricted at the Igh locus. Finally, size-exclusion chromatographic analysis shows that the factor possesses an apparent Mr of 26 kDa. These studies suggest that SEB induces the production of a suppressive factor with properties similar to those exhibited by Ag-induced, and typically Ag-specific, suppressor factors.

Adjuvants, Immunologic↗
PubMed1989

A one-compartment single-pore model for extracorporeal hemoperfusion.

A one-compartment single-pore model is proposed for the dynamic analysis and performance evaluation of a hemoperfusion column under operation. Experimental data obtained from binary systems containing creatinine and uric acid may be well predicted by the theoretically computed curves. This theory offers a means for the preclinical evaluation of any prototype hemoperfusion column.

Adsorption↗
PubMed1989

Dynamics of intercellular communication and differentiation in a rapidly developing mammalian airway epithelium.

A considerable body of data suggests that gap junctions represent channels that facilitate intercellular communication, thereby modulating growth and development. However, direct quantitative evidence supporting such a structure/function relationship is limited. This study has identified a new model in the rapidly developing tracheal epithelium of infant ferrets wherein gap junction prevalence and intercellular transfer of a fluorescent, low molecular weight dye, epithelial cell incorporation of tritiated thymidine, and progressive ciliation of the epithelium have been characterized. This developmental pattern provides favorable conditions for the study of relationships between gap junctions, intercellular translocation of chemical signals, and cell growth and differentiation in a mammalian airway epithelium with a minimum of experimental intervention.

Animals↗
PubMed1989

A clinical evaluation of ultrasonography in the diagnosis of acute appendicitis.

Recently ultrasonography (US) has proven effective in the diagnosis of acute appendicitis. However, the impact of US on surgical decision-making in clinical practice remains unclear. From August 1986 to July 1987, 62 patients with clinical signs of acute appendicitis received US examinations after initial clinical evaluations. According to clinical pictures, they were classified into two groups: group I, clinically typical (Alvarado's score greater than or equal to 7) and group II, clinically dubious (Alvarado's score less than or equal to 6) cases. All group I patients (n = 34) had surgery. Group II patients (n = 28) received close in-hospital observation on an every 4-hour basis for less than 24 hours. However, surgery was performed if Alvarado's score increased up to or above 7 or surgical indications became evident during observation. The pathologic reports and operative findings were retrospectively correlated with the US diagnosis. For group I patients, clinical examination without knowledge of US findings was correct in 30 (88.9%) cases, 26 (86.7%) of which were detected by US. Four (50%) of eight patients with negative US findings had acute appendicitis. In group II, 12 of 15 patients who had surgery had acute appendicitis, and 10 (83.3%) were detected by US. Two (11%) of 18 patients with negative US findings were finally proved to have acute appendicitis. The average duration from initial clinical examination to surgical decision fpr patients with acute appendicitis was 6.8 hours. There were no false-positives in either group. For patients with typical clinical presentation, US is not superior to clinical examination, and surgery is recommended even if US findings are negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗