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Biomedical subjects

T J McCarthy

Publications and source records attributed to T J McCarthy.

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

Human depredation by vampire bats (Desmodus rotundus) following a hog cholera campaign.

Hog cholera control efforts in Belize in 1975 included the slaughter of village pigs, a primary food source for the vampire bat (Desmodus rotundus). The bats then fed on secondary food sources, including humans. In 1 village, 22% of the families interviewed were exposed to attacks: 17 children and 2 adults were bit. Human depredation was not continuous as Desmodus located other hosts.

Adolescent↗
PubMed1988

Property tax exemptions: headed for extinction?

Hospitals face an assault on property tax exemptions that threatens the foundations of all voluntary not-for-profit facilities. The Utah Supreme Court fired the first salvo in this campaign in 1985 in Utah County v. Intermountain Health Care, Inc. The court examined the distinctions between not-for-profit and for-profit hospitals, the extent to which the two hospitals involved were supported by donations and gifts, the "profit" derived from operation, the charges levied on patients, the level of charity care provided, and several other factors before concluding that the hospitals did not qualify as charitable institutions. Since then, efforts at taxing hospitals have grown dramatically. The definition of "charitable" is at the heart of the tax-exemption problem. Charitable is a legal "term of art," which encompasses for more than the simple provision of charity care. The promotion of health is a charitable purpose. Hospitals qualify under the Internal Revenue Code for tax-exempt status because they promote health--not because they provide charity care. Yet all hospitals promote health. What, then, differentiates not-for-profit from for-profit hospitals that justifies a tax exemption? The argument for continued exemption must be made, if at all, on the basis of the community benefit the not-for-profit provides. Charitable institutions exist to serve and benefit the community and to provide an avenue for voluntary association. They help to improve and promote the general welfare through education, religion, and culture. The real benefits of a not-for-profit entity are found in the fulfillment of these concepts.

Charities↗
PubMed1987

The effect of pH and concentration on the rates of kill of benzoic acid solutions against E. coli.

Mathematical models were developed which related benzoic acid concentrations to their D-values at room temperature. Linear regression was used to determine D-values (i.e. the time required for a particular concentration of preservative at specified pH, temperature and medium to cause a 90% reduction in the number of viable organisms, e.g. Escherichia coli. A number of concentrations of benzoic acid at either pH 3 or pH 4 were used. Linear regression of the log D-values versus the log of the concentration was used to derive power curves (a minimum of four points per pH were examined). Concentration exponents, eta-values (the logarithmic values relating changes in rates of kill to specified changes in concentrations) and A-values (extrapolated D-values at 1% concentration), were determined. The effect of pH on the eta and A-values of benzoic acid on E. coli was investigated. Benzoic acid was found to be more sensitive to pH changes than was anticipated from the Henderson-Hasselbalch equation which relates dissociated and undissociated fractions at the two pH levels investigated. However, the sensitivity of preservative activity to dilution at both pH values (3 and 4), as given by the eta-value, remained similar.

Anti-Infective Agents, Local↗
PubMed1986

2,3,5-Triphenyltetrazolium chloride as a novel tool in germicide dynamics.

A novel, colorimetric method using 2,3,5-triphenyltetrazolium chloride (TTC) in tandem with membrane filtration is described for the determination of death rates of Escherichia coli (E. coli) due to microbiocides. This method enables results to be obtained on the same day in contrast to the 18 h required by the accepted aerobic plate count method. The microbiocides investigated were the preservatives 2-bromo-2-nitro-1,3-propanediol (Bronopol), N-(hydroxymethyl)-N-(1,3-dihydroxymethyl-2,5- dioxo-4-imidazolidinyl)-N'-(hydroxymethyl)-urea (Germall II), phenethyl alcohol, and benzyl alcohol. D values (time required per log reduction of E coli) were determined by this method, and equations relating the D values to preservative concentrations were derived [i.e., eta values (the logarithmic values relating changes in rates of kill for specified changes in concentration) and A values (extrapolated D values at 1% concentration) were determined]. these equations are compared with those previously published using the accepted aerobic plate count method. The potential advantages of this method are that it has a broad range of application as TTC is reduced by a wide variety of microbes; the test is easily done; results can be achieved in one day; dead cells do not cause interference; test sensitivity can be increased by increasing the length of incubation time or by using membrane filtration in tandem with TTC reduction; and preservative inactivation may be achieved by filtration and flushing with an inactivator, or by adding neutralizers to the TTC broth.

Colorimetry↗
PubMed1985

Dynamics of disinfection of selected preservatives against Escherichia coli.

Mathematical models were determined relating preservative concentration and D values (decimal reduction times at 25 degrees C; pH 6.9-7.1) against Escherichia coli in aqueous medium. Preservatives investigated were 2-bromo-2-nitro-1,3-propanediol (Bronopol), N-(hydroxymethyl)-N-(1,3-dihydroxymethyl-2, 5-dioxo-4-imidazolidinyl)-N'-(hydroxymethyl)urea (Germall II), phenethyl alcohol, and benzyl alcohol. Linear regression was used to determine D values [i.e., the time required for a particular concentration of preservative at a specified pH, temperature, and medium to cause a 90% reduction of viable organisms (E. coli)] from a number of concentrations of each preservative. Linear regression of the log D values versus the log of the concentration (a minimum of 4 concentrations per preservative) were used to derive power curves. Concentration exponents, eta values (the logarithmic values relating changes in rates of kill for specified changes in concentrations) and A values (extrapolated D values at 1% concentration), were determined. Correlation coefficients for these power fits ranged from -0.987 to -0.999. Plots depicting the closeness of fit of the models to the actual data are shown.

Culture Media↗
PubMed1981

Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls.

Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

Journal Article↗
PubMed1976

The effect of zinc sulphate and of bicitropeptide on tetracycline absorption.

The interaction between tetracyclines and di- and trivalent ions such as are contained in aluminium, magnesium, calcium, iron and zinc-containing salts or complexes or antacids is well documented. The potential for interaction between tetracyclines and zinc and bismuth salts is often not realised, but is emphasised by the findings reported here. The absorption of 250 mg phosphate-potentiated tetracycline hydrochloride was reduced by 75% when administered concurrently with 220 mg zinc sulphate. The absorption of 250 mg phosphate-potentiated tetracycline hydrochloride was reduced by 50% when administered concurrently with 10 ml bicitropeptide, a bismuth-protein complex. Tetracyclines should thus not be administered concurrently with zinc salts or bicitropeptide.

Bismuth↗
PubMed1975

The effect of vehicle composition on the release of chloramphenicol from creams and eye ointments.

The effects that formulation of topical vehicle can have on the bio-availability and effectiveness of active ingrediants are discussed with reference to steroids, salicylic acid and benzocaine. Results obtained for chloramphenicol-containing preparations are presented, and both dissolution curves and cup-plate assays demonstrate that chloramphenicol has far superior release (and hence activity) from creams than from ophthalmic ointments. The latter, however, produce adequate zones of inhibition, and are long-acting.

Biological Assay↗