Biomedical subjects

J Tsai

Publications and source records attributed to J Tsai.

At least 73 records · Page 4Linked to original sources

PubMed1996

EMS characteristics in an Asian Metropolis.

A prospective citywide cohort study was conducted from August 1, 1993, through May 31, 1994 to analyze the epidemiological characteristics of emergency medical services (EMS) in an Asian city. Of 5,459 studied cases, the leading 3 causes were trauma (49.7%), alcohol intoxication (8.6%), and altered mental status (AMS) (6.9%). Half of the studied cases needed no prehospital care and 16.4% needed advanced life support (ALS) care. Traffic accidents accounted for 68% of trauma cases. Of 897 cases requiring ALS care, the two most common causes were AMS and dead on arrival (DOA) (32.1% and 21.2% in medical group, 10.1% and 4.5% in trauma group, respectively). The response time, time on scene, and transportation time were 4.6, 4.3, and 9.4 minutes, respectively. This Oriental EMS system experienced very short prehospital times, many traffic accidents, and extremely few DOA cases. Because few patients required ALS care, an emergency medical technician-based EMS system would probably be able to handle the majority of prehospital patients.

Adolescent↗

PubMed1996

Characterization of the helicase and ATPase activity of human papillomavirus type 6b E1 protein.

Human papillomavirus type 6b (HPV-6b) is one of the most common causes of human genital warts, an important sexually transmitted disease. Discovery of antiviral therapies for this condition has been hampered by the inability to propagate the virus using standard tissue culture techniques and through difficulties in expressing sufficient recombinant viral proteins in vitro. Replication of papillomavirus DNA requires two viral proteins, E1 and E2. In an effort to establish assays to discover compounds active against this virus, we have co-expressed HPV-6b E1 and E2 proteins in insect cells. We demonstrate that the two proteins form a heteromeric complex which can be purified by sequence-specific DNA affinity chromatography. We also demonstrate that the complex has both E1-associated ATPase and ATP-dependent DNA helicase activity and report further characterization of these functions.

Adenosine Triphosphatases↗

PubMed1996

Analysis of prehospital ALS cases in a rural community.

BACKGROUND: An Emergency Medical Services (EMS) system containing the advanced life support (ALS) and manned with paramedics, is developing in many countries in view of the importance of prehospital ALS skills on ALS eligible patients, although previous studies have only revealed that a meager need for ALS in urban community. The purpose of this study is to understand the real demand of ALS in a rural community, so that a well organized and cost-effective EMS system can be developed in this country. METHODS: An EMS system with a single tiered response configuration, using firefighters to give basic prehospital care, stored in computer with some necessary informations was established in Ilan County. Cases with ALS from January 1993 through December 1994 were retrieved from the computer. The ones truely eligible for ALS were reconfirmed and analized in terms of neurological outcome while discharging from hospital, sex, age, response time, time spent on scene, transportation time, as well as whether the cases were trauma or medically induced. RESULTS: Of 11352 cases collected during 731 study days, 594(5.28%) ALS eligible cases (including 211 DOA and 383 nonDOA) were studied. Of 211 DOA, 103(48%) were caused by trauma. The response time, time spent on scene and transportation time in ALS and DOA cases were 5.5min., 4.7min., 13.6min., and 5.6min., 5.6min., and 15.7min., respectively. Of 211 cases of trauma (55% of total ALS cases), traffic accident accounted for 46%. Altered mental status and chest pain or tightness made of 90% of medical induced ALS cases. Five percent of patients felt worsening of condition during transit. One third of patients seemed to experience a bad outcome. CONCLUSIONS: Based on the characteristics of low demand for ALS services, more than half trauma-induced ALS cases, acceptable response time, short transportation time, extremely few medically-induced DOA cases, and quite a poor outcome in the setting of limited prehospital care, a unique EMS system different from that in the United States or in the urban area is needed in the rural area.

Adult↗

PubMed1995

The volume of atoms on the protein surface: calculated from simulation, using Voronoi polyhedra.

We analyze the volume of atoms on the protein surface during a molecular-dynamics simulation of a small protein (pancreatic trypsin inhibitor). To calculate volumes, we use a particular geometric construction, called Voronoi polyhedra, that divides the total volume of the simulation box amongst the atoms, rendering them relatively larger or smaller depending on how tightly they are packed. We find that most of the atoms on the protein surface are larger than those buried in the core (by approximately 6%), except for the charged atoms, which decrease in size, presumably due to electroconstriction. We also find that water molecules are larger near apolar atoms on the protein surface and smaller near charged atoms, in comparison to "bulk" water molecules far from the protein. Taken together, these findings necessarily imply that apolar atoms on the protein surface and their associated water molecules are less tightly packed (than corresponding atoms in the protein core and bulk water) and the opposite is the case for charged atoms. This looser apolar packing and tighter charged packing fundamentally reflects protein-water distances that are larger or smaller than those expected from van der Waals radii. In addition to the calculation of mean volumes, simulations allow us to investigate the volume fluctuations and hence compressibilities of the protein and solvent atoms. The relatively large volume fluctuations of atoms at the protein-water interface indicates that they have a more variable packing than corresponding atoms in the protein core or in bulk water. We try to adhere to traditional conventions throughout our calculations. Nevertheless, we are aware of and discuss three complexities that significantly qualify our calculations: the positioning of the dividing plane between atoms, the problem of vertex error, and the choice of atom radii. In particular, our results highlight how poor a "compromise" the commonly accepted value of 1.4 A is for the radius of a water molecule.

Animals↗

PubMed1995

Productivity and profitability differences between pseudorabies-infected and pseudorabies-noninfected farrow-to-finish swine herds.

Productivity and economic effects of pseudorabies were estimated for a mean-size, farrow-to-finish swine enterprise. A Delphi technique was used to elicit productivity effects from an expert panel. Enterprise budgets for pseudorabies-infected and noninfected herds were constructed by use of these productivity estimates, as well as by use of economic data from secondary sources. Data examined to determine effects on productivity included preweaning, nursery, and growing/finishing pig mortality; breeding hog mortality; feed conversion; labor; and veterinary services and medication expenses. Results indicated that profitability was lowered in infected herds by approximately $6/cwt of swine produced.

Animal Husbandry↗

PubMed1995

Rotating residents' impressions of an ED managed by career emergency physicians.

Rotating residents (RRs) were surveyed to determine their impressions of an emergency department (ED) run by career emergency physicians (EPs), in the hope of generating insights into controversies that occur between the ED and other hospital departments. A questionnaire was distributed to RRs at Taipei Veterans General Hospital in September 1993. The questionnaire inquired about basic data, workload, and ED training and teaching, and also asked respondents for their overall evaluation of emergency medicine and EPs. Of 117 questionnaires issued to residents who had rotated in the ED during the previous 5 years, 60 respondents from the departments of internal medicine, family medicine, chest medicine, neurology, and respiratory therapy completed and returned the questionnaires. Ninety percent believed the workload of the ED to be heavy, and 87% considered two to three months to be an appropriate ED training time. Only 40% were willing to extend their ED training time to achieve a more reasonable workload, and 83% considered their ED residency stressful, with too many patients and long working hours cited as the leading sources of stress. Fear of malpractice suits and difficult interaction with patients and patients' families were also cited as stressful factors. All RRs considered ED training important; self-learning and the accumulation of ED experience, as well as the conference on emergency pitfalls, were the two aspects of training most favored, garnering approval by 92% and 80%, respectively. The overall impression of the RRs on emergency medicine and the performance of EPs was favorable.(ABSTRACT TRUNCATED AT 250 WORDS)

Emergency Medicine↗

PubMed1995

The clinical experience of acute cyanide poisoning.

The authors reviewed the clinical manifestations, complications, and the prognosis affected by Lilly Cyanide Antidote in 21 victims of acute cyanide poisoning over a 10-year period. The clinical signs and symptoms in cyanide poisoning are variable. Among 21 cases, loss of consciousness (15), metabolic acidosis (14), and cardiopulmonary failure (9) were the three leading manifestations of cyanide intoxication. Anoxic encephalopathy (6) was not uncommon in the severely intoxicated victims. Diabetes insipidus (1) or clinical signs and symptoms mimicking diabetes insipidus (3) may be an ominous sign to encephalopathy victims. The major cause of fatal cyanide poisoning is the intentional ingestion of cyanide compounds as part of a suicide attempt. Decrease of arteriovenous difference of O2 partial pressure may be a clue for the suspicion of cyanide intoxication. Although the authors cannot show a statistically significant difference (P = .47) for the Lilly cyanide antidote kit in terms of improving the survival rate for victims of cyanide poisoning, the antidote kit was always mandatory in our study in the cases of severely intoxicated victims who survived. Early diagnosis, prompt, intensive therapy with antidote, and supportive care are still the golden rules for the treatment of acute cyanide poisoning, whether in the ED or on the scene.

Acute Disease↗

PubMed1995

Oligonucleotide-mediated modulation of mammalian gene expression.

The notion that oligonucleotides can modulate gene-specific expression was established more than a decade ago. Recent advances in molecular genetics have broadened the armamentarium used to manipulate gene expression in biological systems including triplex DNA, antisense RNA/DNA, and ribozymes (catalytic RNA). These oligonucleotides demonstrated important early application to the elucidation of cellular signaling pathways. More recently, studies with these agents have probed their utility as potential therapeutic agents, especially in the realm of cancer. With the implementation of gene therapy in early clinical trials, oligonucleotide-mediated suppression of gene expression has emerged as an important strategy for gene therapy. This review will discuss the current knowledge in this field, focusing on the biology of triplex DNA, antisense oligonucleotides, and ribozymes.

Animals↗

PubMed1995

Studies on the optic chiasm of the leopard frog. II. Organization of retinotectal fibers in the optic chiasm.

The organization of retinotectal fibers in the optic chiasm was investigated using horseradish peroxidase (HRP) histochemistry and electrophysiological recording. HRP injection into a small region of the tectum led to retrograde staining of labeled fibers in a circumscribed region of the chiasm and staining of labeled ganglion cells in the contralateral retina. In each instance labeled tissue was spread over a greater proportion of the area of a chiasm section than over the flattened retina. Fibers originating in central (older) retina are located in dorsal chiasm. Fibers originating in peripheral (younger) retina are located in ventral chiasm. Viewed with the electron microscope, labeled unmyelinated fibers are admixed with labeled myelinated fibers. Neuronal activity was monitored with an extracellular microelectrode from points in dorsoventral tracks in the chiasm. Multiple units were recorded at each chiasm location. Using visual stimuli, the receptive fields of the units were mapped. The fields were distributed along an arc across the visual field. At ventral chiasm recording sites the arc was in the peripheral part of the visual field. In succeeding dorsal sites the arcs were concentrically arranged so that the more dorsal the chiasm recording site, the more central was the arc in the visual field. Thus, in the optic chiasm, retinal fibers appear to be organized chronotopically but not retinotopically. Fibers of the same age but from different locations in the retina are mixed together.

Animals↗

PubMed1995

[Three years' experience of emergency medical services in Ilan County].

The Emergency Medical Services (EMS) aims to improve the survival rate of patients who are dead on arrival (DOA) at hospital, particularly those whose coronary artery disease (CAD) has induced sudden death. Based on the low prevalence of CAD-induced sudden death in Taipei city, as well as the differences between urban and rural communities in Taiwan, an understanding of the characteristics of rural areas is necessary in order to establish a well-organized and cost-effective EMS policy in this country. The data were drawn from a computer database which stored prehospitalization information from Ilan County from 1992 through 1994, including age, sex, response time, time spent on the scene, transportation time, service unit, reasons for emergency call and trauma mechanism. In 1096 study days, 20058 cases (18/day) were collected, of which 16560 (15/day; 83.6%) were transported to hospital. Trauma was responsible for the majority (77%) of these cases, followed by chronic diseases (4.0%), trivial matters (2.6%), drunkenness (2.3%), altered mental status (2.3%), suicide attempt (2.2%), and cardiac arrest (1.8%). Among the trauma cases, traffic accidents were the most common cause (84%); motorcycle accidents comprised 65% of trauma cases. The average response time was 6.6 minutes, time spent on the scene was 3.6 minutes, and transportation time was 17.7 minutes. Trauma and non-trauma accounted for half of the DOA cases, with each making up 0.9% of the total cases transported. In conclusion, it is important that the EMS needs of each community are known for a proper system appropriate to that particular area to be developed.

Adolescent↗

PubMed1994

The growth of PC12 neurites is biased towards the anode of an applied electrical field.

We have exposed cultures of PC12 cells to uniform DC electric fields following the addition of NGF. The success of these experiments relied upon the design of new chambers enabling fields to be applied to mammalian cell cultures. After 48 h of field application, the distribution of neurite outgrowths was biased towards the anode. More neurites faced the anode than would be expected if growth was uniform. The magnitude of this bias was strongly correlated with field strength, with a threshold value of about 1 mV/mm. At field strengths above 30 mV/mm, the neurites growing towards the cathode were shorter than those growing towards the anode or perpendicular to the field. This response was not correlated with field strength. This report confirms that mammalian neurons respond to electrical fields and supports the notion that neurites are influenced by endogenous electrical fields during development. As far as we are aware, this is the only report that documents a response towards the anode.

Animals↗

PubMed1994

Tail length determination in bacteriophage T4.

This report identifies a protein that regulates tail length in bacteriophage T4. Earlier work (Duda et al., 1990) suggested that the gene 29 protein could be involved in T4 tail length determination as a "template" or "tape-measure", similar to that proposed for the gene H protein in bacteriophage lambda. We have altered the length of a recombinant gene 29 by constructing deletions and duplications in different parts of the gene. Each of these constructs was incorporated into the high-level expression vector, pET-11d. Seven plasmids with different lengths of gene 29 were made and used in complementation studies. We have found that the length of the tail can be decreased by deleting the C-terminal part of gene 29 or increased by forming duplications in different parts of this gene, and that the length of the tail can be proportional to the size of the engineered protein. Unlike phage lambda, plasmids with deletions in the middle of gene 29 or from the N-terminal end produced correspondingly smaller but inactive gene 29 protein and no viable phage were formed. Our results show that alterations in the length of gene 29 protein proportionately alters tail length, and argue strongly for a scheme in which 29 protein is a ruler or template that determines tail length during tail assembly.

Bacteriophage T4↗

PubMed1994

Ureaplasma urealyticum biovar specificity and diversity are encoded in multiple-banded antigen gene.

Ureaplasma urealyticum is a commensal organism of the lower genital tract of females, but in a subpopulation of individuals, it can invade the upper genital tract. It is a significant cause of chorioamnionitis and neonatal morbidity and mortality. There are 14 recognized serovars of U. urealyticum; these can be divided into two distinct clusters or biovars. Biovar 1 is composed of serovars 1, 3, 6, and 14, Biovar 2 is composed of serovars 2, 4, 5, 7, 8, 9, 10, 11, 12, and 13. We previously identified a surface antigen, the multiple-banded (MB) antigen, which contains both serovar-specific and cross-reactive epitopes. Genotypic characterization of the C-terminal region of the MB antigen of serovar 3 indicates that serovar specificity and MB antigen size variation reside in that domain. In the present study, we used PCR analysis with primers derived from the serovar 3 MB antigen gene DNA sequence to determine if the MB antigen gene was present in the remaining 13 reference serovars as well as in invasive clinical isolates. The results indicated that not only was the MB antigen gene present in all serovars but that the genes' 5' regions were markers of biovar specificity and diversity. Further analysis of this region should reveal the phylogenetic relationship among serovars of U. urealyticum and, possibly, their invasive potential.

Antigenic Variation↗

PubMed1994

The clinical implication of theophylline intoxication in the Emergency Department.

We reviewed the clinical manifestations of 53 episodes of theophylline intoxication in 50 patients over a one year study period, in order to identify the specific features as they presented to the Emergency Department (ED). There was a trend to an increase in the serum theophylline concentration with increased severity of clinical features, but the difference between the mild and the moderate cases was not statistically significant. The most common symptoms and signs were gastrointestinal complaints, sinus tachycardia, and atrial arrhythmias. Mixed atrial and ventricular arrhythmias, which are rarely mentioned as a specific feature of theophylline intoxication, were found in 16% of our patients and accounted for 29% of the cardiovascular manifestations. Four patients developed rhabdomyolysis, which presumably was secondary to a seizure or profound hypokalaemia. Cases of theophylline intoxication presenting to the ED had higher serum concentrations of theophylline and tended to have more severe toxicity than those patients in the non-ED group. Delayed diagnosis may contribute to the severity of the outcome, since severe cases in the ED were usually suspected to have developed intoxication at some point later in the stay in the ED than at the time of presentation, or after admission to the hospital, thus permitting the occurrence of an additional iatrogenic component to the intoxication. They also complained of symptoms not associated with the theophylline toxicity, which may have diverted the physician's attention from recognizing this concurrent problem.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

Predicting the number of herds infected with pseudorabies virus in the United States.

Epidemiologic modeling of the likely herd-to-herd transmission of pseudorabies virus (PRV) was developed to assess the progress and potential for the PRV-eradication program in the United States. The herd-to-herd transmission of PRV over a 20-year period (1993 to 2012) in the United States was simulated under various scenarios, which included variable program-funding levels and variable prevalences. A transition model (Markov process model) was used to predict yearly changes in herd prevalence of PRV infection. Five mutually exclusive states of nature for herds were assumed: uninfected and not vaccinated; uninfected and vaccinated; known to be infected and not vaccinated; known to be infected and vaccinated; and infected, but not known to be infected. Three prevalences for states in the United States were assumed: higher prevalence, moderate prevalence, and lower prevalence. Three funding levels were assumed: no eradication program, continued funding at the current level, and increased funding of 25%. Estimates made by an expert panel for determining probabilities in the state-transition matrices were used. A model also was developed, and was considered to be the most optimistic scenario likely under increased funding of 25%. The most optimistic estimates of the probabilities that still lay within the range of estimates made by the expert panel were used for this model. Only the optimistic transmission matrices allowed for total eradication of PRV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Hydrophobic affinity chromatography of human thrombin.

Hydrophobic affinity chromatography on p-chlorobenzylamido-agarose (p-CBA-agarose) was used to characterize various modified forms of human thrombin. Native alpha-thrombin bound tightly to the column and was eluted with either acetonitrile or 1,4-dioxane, while the catalytically inactive prethrombin 2 did not bind to the matrix. Site-specific chemical modification with pyridoxal 5'-phosphate resulted in the loss of at least 80% of fibrinogen clotting activity but did not influence the binding of thrombin to p-CBA agarose. Modification of thrombin with pyridoxal 5'-phosphate is thought to occur at the fibrinogen-binding site and the heparin-binding site. In contrast, binding of thrombin to p-CBA agarose was eliminated by modification of the active site histidine using either H-D-phenylalanyl-L-prolyl-L-arginine chloromethylketone or dansyl-L-glutamyl-glycyl-L-arginine chloromethylketone but not with tosyl-L-lysine chloromethylketone. The presence of either hirudin or heparin blocked the binding of thrombin to p-CBA-agarose but dansyl-arginine-N-(3-ethyl-1,5-pentanediyl)amide had no effect. These results indicate that p-CBA agarose binds to thrombin outside of the enzyme active site and its use should be valuable in characterizing site-specific modified thrombins obtained by either protein engineering or chemical modification.

Acetonitriles↗

PubMed1993

The divergence of Trichomonas vaginalis virus RNAs among various isolates of Trichomonas vaginalis.

Trichomonas vaginalis virus is a double-stranded (ds) RNA virus found in the parasitic protozoan T. vaginalis. To examine the possible existence of related viruses in various T. vaginalis strains and isolates, we screened 20 such isolates and found the characteristic 5.5-kb viral ds RNA in 16 of them. An additional 0.5-kb ds RNA band was also identified in 10 of these virus-infected T. vaginalis isolates. In a local isolate T1, this 0.5-kb ds RNA cross-hybridized with the 5.5-kb ds RNA. Preliminary evidence from CsCl buoyant density gradient centrifugations suggests that the two ds RNA species are encapsidated in separate viral particles by the same capsid protein. The 5.5-kb ds RNA in isolate T1 exhibited moderate hybridization with the prototype 5.5-kb ds RNA in T. vaginalis stratin NIH-Cl. Little cross-hybridization was observed among the 5.5-kb ds RNAs from T. vaginalis isolates JH32A No. 4, T1 and T5, although the viral proteins in these isolates are of similar molecular weight and share common epitopes as viewed by Western blotting. Hybridization characteristics of the 5.5-kb ds RNAs in individual isolates were further analyzed, and the results suggest great ds RNA divergence among the T. vaginalis viruses. Interestingly, the 0.5-kb ds RNA in different isolates of T. vaginalis also exhibited divergence in patterns closely associated with that of the 5.5-kb ds RNA.

Animals↗

PubMed1993

Murphy's Button revisited. Clinical experience with the biofragmentable anastomotic ring.

Use of the biofragmentable anastomosis ring (BAR) was attempted in 33 patients at two New York City institutions and employed in 31 instances. Anastomoses performed were end-to-end enterocolic (n = 15), colocolic (n = 15), and side-to-side colocolic (n = 1). Patients ranged in age from 27 to 86 years, with the following diagnoses: primary colon cancer, 15; sessile adenoma, four; colostomy, five; diverticulosis, two; metastatic cancer with obstruction, multiple polyposis, perforated appendiceal mass, malignant carcinoid of appendix, intussuscepting right colon mass, one each. In two instances use of the device was aborted because of concern with the blood supply to the bowel wall in one and tissue edema in another. The average duration of postoperative ileus was 4.7 days. Two patients were subsequently treated for small bowel obstruction thought unrelated to use of the anastomotic device. There were no deaths and no evidence of stricture.

Adult↗