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Biomedical subjects

J Hsieh

Publications and source records attributed to J Hsieh.

48 records · Page 3Linked to original sources
PubMed1992

Biological tags for stock separation in Pacific herring Clupea harengus pallasi in California.

A survey of the parasites of Pacific herring (Clupea harengus pallasi) off northern California identified 1 species of Acanthocephala, 1 species of Cestoda, 2 species of Copepoda, 1 species and 1 family of Digenea, 3 species of Nematoda, and 3 species of Protozoa. From this survey, Lacistorhynchus dollfusi (Cestoda), Parahemiurus merus (Digenea), and Anisakis simplex, Contracaecum sp., Hysterothylacium sp. (Nematoda) were selected as potential tags. Herring were collected in Tomales, San Francisco, and Monterey bays for the following 9 yr and examined for these select parasites. The results suggest that these parasites can be used to distinguish the spawning stocks of San Francisco and Tomales bays. The distribution of the definitive hosts of the respective parasites suggests that the Tomales Bay fish are offshore during the nonbreeding season and the San Francisco Bay fish onshore. The similarity in parasitism between San Francisco Bay and the nonspawning population in Monterey Bay suggests that these 2 populations represent a single stock.

Animals↗
PubMed1991

Differential effects of sodium butyrate and hexamethylene bisacetamide on growth and secretion of cultured human endocrine tumor cells.

Advanced gastrointestinal endocrine tumors respond poorly to conventional chemotherapy. In this study we examined the effects of two agents that promote cellular differentiation, sodium butyrate and hexamethylene bisacetamide, on the in vitro growth and secretory responses of a human pancreatic carcinoid (BON) and human gastrinoma (PT-2 and PT-SM) cell lines that have been established in our laboratory. We found that both sodium butyrate and hexamethylene bisacetamide strongly inhibited growth of BON, PT-2, and PT-SM cells. With continuous exposure of BON cells to sodium butyrate (2 mmol/L), the doubling time was prolonged, from 60 hours in controls to 156 hours, and saturation density was reduced to 28% that of controls. Hexamethylene bisacetamide (4 mmol/L) reduced saturation density to 37% that of controls in BON cells and prolonged the doubling time, from 60 hours to 103 hours. Antiproliferative effects of similar magnitudes were observed in the gastrinoma cell lines. In contrast, differential effects were produced on amine biosynthesis in BON cells; sodium butyrate stimulated levels of 5-hydroxytryptamine in the cells, whereas hexamethylene bisacetamide caused a profound dose-dependent inhibition of amine biosynthesis. The significant antiproliferative activity of sodium butyrate and hexamethylene bisacetamide and the inhibitory effects of hexamethylene bisacetamide on amine biosynthesis warrant evaluation of these agents or analogues for treatment of metastatic carcinoid and gastrinoma.

5-Hydroxytryptophan↗
PubMed1991

Reinforcement of motor evoked potentials in patients with spinal cord injury.

Transcranial magnetic stimulation of the motor cortex has been used to investigate the putative existence of spared motor pathways in spinal cord injured patients with clinically complete paralysis. Particular consideration was given to methods of neurological reinforcement likely to minimize the risk of false negative interpretation of absent motor evoked potentials (MEPs). The principal methods of reinforcement included target and remote muscle contractions and conditioning of MEPs with a brief (20 msec) train of cutaneous stimulation (500 Hz: duration 0.1 msec) delivered 20-150 msec prior to cortical stimulation. Twelve control subjects and 26 patients with severe traumatic spinal cord injury underwent cortical stimulation delivered from a Cadwell MES-10 (70-100% intensity) through a 9-cm focal-point coil. Electromyographic responses were recorded from surface electrodes in bipolar configuration and amplified (3 dB down at 10 Hz-1 kHz) prior to storage. MEPs were recorded, following reinforcement, in muscles with clinically complete paralysis in 4/26 patients. In each case, MEPs were of low amplitude (less than 0.5 mV), polyphasic, and with variable and prolonged latencies. MEPs were evoked in severely paretic (clinically incomplete paralysis) muscles in 6/8 patients only when neurological reinforcement was employed. Conditioning of MEPs in tibialis anterior with preceding cutaneous stimulation to the plantar surface (subthreshold for evoking a flexion reflex) yielded a well-defined modulation of MEP amplitude in control subjects. An early (Conditioning-Test (C-T) intervals 20-45 msec) period of inhibition of MEPs (mean = 60% of control) was followed by a period (C-T intervals 50-90 msec) of facilitation (mean = 345%) and a subsequent (C-T intervals 90-150 msec) period of inhibition (mean = 0%). In spinal cord injured patients the same conditioning paradigm failed to reveal MEPs, but did result in the appearance of suprathreshold flexion reflexes in 2 patients at 20-55 msec C-T intervals. This summation of convergent but subliminal cortical and cutaneous inputs to the target motoneuron pool provided additional evidence of preserved cortical influence on segmental structures that was not detectable by other means. These results extend previous reports of electrophysiological evidence of spared motor pathways in spinal cord injured patients with complete paralysis, and affirm the need for neurological reinforcement as a routine procedure in cortical stimulation studies of spinal cord injuries.

Adult↗
PubMed1990

Evaluation of the effect of azapropazone on neutrophil migration in anaesthetized swine using a multichamber blister suction technique.

1. The purpose of this study was to determine the in vivo inhibitory efficacy of azapropazone on neutrophil migration. The effects of azapropazone given at a dose of 100 mg kg-1 i.v. every 2 h on the neutrophil migration into skin inflammation sites (blister fluid) as well as into an autologous serum (+/- chemoattractant) placed above the blister surface (2nd chamber) were determined. 2. Azapropazone treatment schedule maintained blood levels at 70-100 micrograms ml-1 throughout the time course (360 min) of the experiment. 3. Azapropazone significantly inhibited (48 +/- 6%) neutrophil migration into the blister fluid (as evident from the decrease in myeloperoxidase activity). 4. Azapropazone significantly inhibited the neutrophil migration into the autologous serum either with (65 +/- 5%) or (35 +/- 6%) without the chemoattractant, formyl-methionyl-leucyl-phenylalanine (FMLP). The chemoattractant, FMLP, markedly increased neutrophil migration into the autologous serum by approximately 1.5 to 2 times the non-FMLP treated group. Azapropazone was more efficacious in inhibiting the neutrophil migration in the presence of FMLP than in its absence. 5. We conclude that azapropazone is an effective inhibitor of neutrophil migration into topically inflamed sites in anaesthetized swine.

Anesthesia↗
PubMed1990

A "treated" model for severe hemorrhagic shock: a comparison of conventional and germ-free animals.

In an unanesthetized "treated" model of severe hemorrhagic shock, a bacteremia originating from the animal's enteric flora was demonstrated by finding radiolabeled Escherichia coli in the blood as early as 2 hr after the onset of shock. In 50 patients admitted to our trauma unit, the observation was similar, with 56% positive blood cultures, when their mean arterial blood pressure was 80 mmHg or less. The relationship of bacterial translocation and the high post-shock mortality in our conventional (CV) animal model is being evaluated in germfree (GF) Sprague-Dawley rats. Preliminary observations in 15 GF animals showed 80% survival at 24 hr post-shock, 54% at 48 hr, and 42% at 72 hr compared with those of CV animals in previous experiments with survival at similar times of 73%, 20% and 7%, respectively.

Animals↗
PubMed1989

Does the bacteremia observed in hemorrhagic shock have clinical significance? A study in germ-free animals.

We have recently reported the rapid appearance of bacteria and endotoxin in the blood of rats and of trauma patients in the course of 30 minutes to 2 hours of hemorrhagic shock. The current study was designed to determine the effect of this bacteremia and endotoxemia on survival. Thirty-three conventional (C:group 1) and 36 germ-free (GF:group 2) Sprague Dawley rats were subjected to our previously described model of treated hemorrhagic shock. Survival in the GF group was significantly better than the C group at 24, 48, and 72 hours after shock. Endotoxin levels were elevated in 88% of C group during shock and in 28% of GF group. The gut of the GF animal contains endotoxin (26 ng/gm of stool) as does the sterile food supply (393 ng/gm of rat chow).

Animals↗
PubMed1976

Lessening of adverse biochemical effects of shock in newborn puppies by general anesthesia.

A shock preparation has been developed which produces the expected anaerobic metabolism in neonatal beagle puppies less than 7 days old. Lactic acid production was found to be significantly higher in shocked puppies operated upon under local anesthesia than when the same procedures were performed in shocked puppies under general endotracheal anesthesia. These findings suggest that general anesthesia may be safer in the very sick human neonate.

Anesthesia, General↗
PubMed1975

Intestinal pH as a factor in selection of animal models for bioavailability testing.

Previous in situ studies showed that intestinal drug absorption is strongly influenced by intestinal pH. Three animal species considered for bioavailability testing were studied in situ to determine intestinal pH. Results from the rat and dog correlated well with results in humans, while results from the rabbit did not. The rabbit appears to be a poor candidate for attempted animal-human bioavailability correlations.

Animals↗
PubMedDate not supplied

Employee advisory boards as a vehicle for organizing worksite health promotion programs.

PURPOSE: The purpose of this article is to describe the "employee advisory board model" applied in the Treatwell program, a worksite nutrition intervention program. DESIGN: The employee advisory boards of five of the seven intervention worksites participating in the Treatwell program were surveyed. Results were compared with results of employee surveys conducted in these five worksites. SETTING: The five worksites included in this study are among 16 participating worksites from Massachusetts and Rhode Island. SUBJECTS: Of the 95 board members represented in the five worksites, 88% responded to the survey. This article also presents results from the 698 respondents of the five intervention worksites where the board surveys were conducted. INTERVENTION: The boards in each worksite participated in planning, promoting, and implementing this program in each worksite. MEASURES: Respondents to the board survey were asked about their participation on and satisfaction with the board and factors they thought contributed to its effectiveness. A survey of all employees included information on demographics and program participation. RESULTS: Board members reported that they were highly satisfied with the board's functioning. Board member hours spent on Treatwell activities were directly related to the proportion of employees aware of the program. (r = .82). The boards' effectiveness was limited by conflicting priorities between the job and board responsibilities. CONCLUSION: The employee advisory board model provides promise for increasing worker awareness of worksite health promotion programs through enhanced worker ownership.

Adult↗