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Biomedical subjects

H Tai

Publications and source records attributed to H Tai.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effects of the kallikrein-kinin system on phasic coronary vasospasm in dogs.

It is well known that kinins are liberated from kininogen in blood during angina attack to maintain blood flow in coronary artery. We examined the effects of bradykinin, one of kinins, on the coronary artery other than vasodilation. The isolated canine coronary artery ring was suspended in gassed (95% O2, 5% CO2) Krebs-Henseleit buffer at 37 degrees C in vitro. The experimental phasic contraction of coronary artery was induced by 6 x 10(-4)M of 3,4-diaminopyridine which decreases K conductance (Y. Uchida, Jpn. Circ. J: 49, 128, 1985). The effect of bradykinin and other substances on the cycle length of contraction (CL), the peak tension of contraction phase (PT) and the tension during relaxation phase (RT) were observed. The phasic contraction was eliminated by 10(-7)M nifedipine and 10(-6)M diltiazem which block voltage dependent Ca channels. These Ca blockers reduced PT, but slightly increased CL, and weakly reduced RT. The phasic contraction was also eliminated by 10(-6)M bradykinin. However, bradykinin, unlike Ca blockers, did not reduce PT, but markedly prolonged CL and decreased RT significantly. This inhibition mode was very similar to those of nicorandil which increases K conductance. These data suggest that bradykinin plays a protective role in coronary vasospasm, and this antivasospasm effect may be mediated through the increase in K conductance.

Animals↗
PubMed1980

Heavy metal concentrations in soils of five United States cities, 1972 urban soils monitoring program.

Lead, mercury, cadmium, and arsenic levels were determined in soil samples from Des Moines, Iowa, Fitchburg, Massachusetts, Lake Charles, Louisiana, and Reading and Pittsburgh, Pennsylvania, as part of the 1972 Urban Soils Monitoring Program. Sampling sites within each Standard Metropolitan Statistical Area (SMSA) were defined as urban or suburban based on their position either within or outside the official city limits, respectively. In addition, each site was classified lawn or waste according to the maintenance it received. Except in Fitchburg, urban soils of each SMSA contained significantly higher mean concentrations of cadmium, lead, and mercury than did suburban soils. Mean urban soil concentrations in each SMSA except Des Moines and Reading, where urban levels were significantly higher. Generally, the metal concentrations in lawn and waste areas did not differ significantly. The results indicate a general contamination of these areas, probably as a result of fallout of airborne metal aerosols from industrial processes and/or fossil-fuel combustion.

Arsenic↗
PubMed1980

Residual concentrations of propanil, TCAB, and other pesticides in rice-growing of soils in the United States, 1972.

Ninety-nine soil samples from the rice-growing states of Arkansas, California, Louisiana, Mississippi, and Texas were collected, primarily to monitor the herbicide propanil. No residual concentrations of propanil were detected in any of these samples, but TCAB, a propanil transformation product, was detected in six samples at concentrations ranging from 0.01 ppm to 0.05 ppm. Organochlorine and organphosphorus pesticide determinations were also performed. The compounds dieldrin, aldrin, and DDT and its metabolites were found more frequently; endrin and chlordane were found less frequently. The organophosphorus pesticides diazinon and parathion were detected occasionally.

Anilides↗
PubMed1979

Pesticide residue levels in soils and crops from 37 states, 1972--National Soils Monitoring Program (IV).

Residue data from the 1972 (FY--73) National Soils Monitoring Program are summarized. Composite samples of agricultural soil and mature crops were collected from 1,483 of the 1,533 selected 4-hectare sites in 37 states. Analyses were performed for organochlorine and organophosphorus compounds, trifluralin and polychlorinated biphenyls (PCBs); analysis for atrazine was performed only when pesticide application data indicated current-year use. Organochlorine pesticides were detected in 45 percent of the soil samples. The most frequently detected compound was dieldrin, found in 27 percent of all soil samples. Other compounds detected, in order of frequency, included DDT, aldrin, chlordane, and heptachlor epoxide, found, respectively, in 21, 9, 8, and 7 percent of all soil samples. Crop samples were collected from 727 sites. All were analyzed for organochlorines; analyses were performed for organophosphates and atrazine only when pesticide application data indicated current-year use. For all crops, 40 percent of the samples contained detectable levels of organochlorines and 10 percent contained detectable levels of organophosphates. Atrazine was not detected.

Agriculture↗
PubMed1979

Pesticide residue concentrations in soils of five United States cities, 1971--urban soils monitoring program.

Soil samples from five metropolitan areas including Baltimore, Maryland; Gadsden, Alabama; Hartford, Connecticut; Macon, Georgia; and Newport News, Virginia were analyzed for elemental arsenic, organochlorine pesticides, and polychlorinated biphenyls (PCBs). A representative number of samples were analyzed for organophosphorus pesticides, but none was detected. All areas exhibited heavy soil concentrations of organochlorine pesticides including sigma DDT, aldrin, dieldrin, photodieldrin, chlordane, heptachlor, heptachlor epoxide, endrin, endrin ketone, and endosulfan sulfate. PCBs were detected in three of the five metropolitan areas. Within the metropolitan areas, samples from the urban, or core city, locations generally had higher pesticide concentrations than did samples from suburban locations. Finally, pesticide residue concentrations were generally higher in soils of metropolitan areas than in nearby agricultural soils.

Arsenic↗
PubMed1978

Pesticide residue levels in soils and crops, 1971--National Soils Monitoring Program (III).

Data from the 1971 National Soils Monitoring Program are summarized. Composite samples of soil and mature crops were scheduled for collection from 1,533 4-hectare sites in 37 states. Analyses were performed on 1,486 soil samples for organochlorines, organophosphates, PCBs, and elemental arsenic; samples were analyzed for atrazine only when pesticide application data indicated current-year use. Organochlorine pesticides were detected in 45 percent of the soil samples in the following order of frequency: dieldrin, sigmaDDT, aldrin, chlordane, and heptachlor epoxide. Most pesticide levels ranged from 0.01 to 0.25 ppm. Crop samples were collected from 729 sites, and all were analyzed for organochlorines. Crop samples were analyzed for organophosphates and atrazine only when pesticide application data indicated current-year use. Organochlorines were detected in 42 percent of the crop samples analyzed, organophosphates in 13 percent, and atrazine in 1 percent.

Arsenic↗
PubMed1976

Pesticide residues in urban soils from 14 United States cities, 1970.

Soil in 14 cities was sampled and analyzed for arsenic and chlorinated hydrocarbon pesticide residues. Heavy loads of chlorinated hydrocarbon residues were detected in the soil. In addition to DDT and its metabolites, chlordane, dieldrin, endrin, heptachlor, heptachlor epoxide, and toxaphene were detected. District variation appeared in some residue levels among cities. Pesticide residue levels in urban soils were generally higher than the residue levels detected in cropland soils of the same States.

Arsenic↗
PubMed1976

Pesticide levels in hay and soils from nine states, 1971.

In 1971 hay and soil samples were collected in 9 States to determine the incidence and levels of pesticide residues in hayfields. Residues were detected in 8 percent of the soil samples and 29 percent of the hay samples. DDT and its metabolites, DDE and TDE, were contained in 2 soil samples and 21 hay samples. Heptachlor epoxide and chlordane were detected in 1 soil sample, dieldrin in 5 soil samples, and diazinon in 4 hay samples.

Hydrocarbons, Chlorinated↗
PubMed1975

Pesticide and mercury residues in commercially grown catfish.

In 1970, 54 commercial catfish farms in Arkansas and Mississippi were sampled for pesticide and mercury residues. Pesticide residues above FDA action levels were detected in 15 percent of the fish samples. Data on residues in sediment, fish feed, and source water suggest that fish were not being contaminated from these sources. Average fish residue per county was, however, strongly correlated with the percent of total acres planted in cotton and soybeans. Results strongly suggest that cotton production was the primary source of contamination. Actual routes of movement have not been clearly defined but aerial transport seems most probable.

Animal Feed↗