Biomedical subjects

C R Hicks

Publications and source records attributed to C R Hicks.

23 records · Page 2Linked to original sources

PubMed1991

Interactions between Pseudomonas aeruginosa and iodophor germicides in milking parlor udder wash water systems.

In a field study of 29 dairy farms, Pseudomonas aeruginosa was isolated more frequently (P = 0.05) from milking parlor udder wash water systems containing iodophor germicides than from those with no germicide. Most available iodine (AI2) concentrations were below the recommended level of 25 ppm (25 microgram/ml). Rubber and polyvinyl chloride hoses caused rapid decreases in the AI2 concentrations of 25 ppm iodophor solutions. AI2 dropped from 25 ppm to 6 ppm or less in 240 min for solutions contained in either polyvinyl chloride or rubber, compared with solutions in glass, which were unchanged in 240 min. Addition of inactivated iodophor solution to aqueous cultures resulted in significantly higher (P less than 0.05) numbers of P. aeruginosa at 10 and 24 h postinoculation. P. aeruginosa was grown in polyvinyl chloride tubing and exposed twice daily to 0, 10, or 25 ppm of AI2. None of the exposure concentrations eliminated the bacteria from the hoses, and bacterial numbers were not significantly different in hoses exposed to 0 and 10 ppm by the eighth treatment day. Bacteria taken from the water in these hoses were exposed to different concentrations of iodophor solution. Iodophor concentrations which will kill 50% of P. aeruginosa cultures previously exposed to 0, 10, and 25 ppm of AI2 were predicted to be 3.0, 11.8, and 20.8 ppm, respectively.

Animals↗

PubMed1989

Effects of neurokinins on ion transport and sulfated macromolecule release in the isolated ferret trachea.

The secretory actions of substance P (SP) were studied by examining its effects on ion transport and sulfated macromolecule release in the isolated ferret trachea. Responses to serosally administered SP were unmasked by thiorphan, suggesting that SP administered by this route was degraded by neutral endopeptidase. Therefore, the serosal actions of neurokinins and neurokinin analogues were studied in tissues pretreated with thiorphan. In thiorphan-treated tissues, SP dose-dependently increased the short-circuit current (Isc) with a maximum increase of 0.50 +/- 0.07 mueq/cm2.h above baseline. The SP-induced increase in Isc was inhibited by bumetanide but not by amiloride, suggesting the involvement of electrogenic Cl- secretion. The direct measurement of ion fluxes, however, failed to detect a significant unilateral movement of Cl- from the serosa to mucosa, probably due to a relatively small and transient increase in Isc produced by SP. Instead, SP (10(-6) M) induced large, electroneutral secretion of Na+ and Cl-. In addition, SP stimulated sulfated macromolecule output. The rank order of potency in increasing both Isc and sulfated macromolecule release among neurokinins and their analogues was SP = SP-methyl ester greater than neurokinin A greater than neurokinin B greater than senktide. These findings indicate that the secretory responses to SP are probably mediated by NK-1 receptors.

Amiloride↗

PubMed1987

Pseudomonas mastitis: difficulties in detection and elimination from contaminated wash-water systems.

Histories of 4 dairy herds with increased incidence of Pseudomonas mastitis associated with contaminated wash hoses in milking parlors are described. Problems of detection and elimination of the organism from contaminated water sources and the inadequacy of iodide germicides in eliminating Pseudomonas are discussed. In problem herds, greater numbers of organisms often are found in the water left standing in the wash hoses between milkings. Thus, flushing of hoses before their use in the milking process may be beneficial in reducing exposure of the cows to the organism.

Animals↗

PubMedDate not supplied

Keratoprostheses: advancing toward a true artificial cornea.

Keratoprosthesis surgery is carried out in very few centers. Elaborate surgical techniques and high complication rates limit the application of currently available keratoprostheses (KPros). However, the clinical need for an alternative to donor tissue has sparked considerable research interest in the development of new KPros. This paper charts the evolution of KPros from the earliest devices to those currently used, describes their drawbacks and discusses the specifications of an ideal device. Recent research focuses upon the use of porous polymers as the skirt component of core-and-skirt KPros in order to obtain improved biological integration of the prosthetic material. Developments in biomaterials technology make a KPro analogous to a donor corneal button an increasingly realistic goal. However, two particular problems still need to be addressed. First, it must be demonstrated that secure long-term fixation that is able to withstand trauma is achievable in a full-thickness artificial cornea. Second, an ideal artificial cornea for a wet eye requires an epithelialized surface, and this has yet to be achieved.

Animals↗

PubMedDate not supplied

Human papillomavirus DNA is present in a subset of unselected breast cancers.

OBJECTIVE: The major molecular events in the genesis of most breast cancers are unknown. However, human papillomaviruses (HPV) have been reported to be found in a significant portion of breast cancers of women with concomitant cervical intraepithelial neoplasia III. To investigate a potential HPV-breast cancer link, we carried out a small survey to identify HPV in unselected, general breast cancer tissues. STUDY DESIGN/METHODS: Deoxyribonucleic acid (DNA) was isolated from 17 breast cancer tissues (and one cervical swab) taken from our local, randomly selected patient population. Two different previously characterized broad-spectrum primer sets (targeting the E6/E7 or L1 regions) were used to amplify HPV DNA, and another primer set was used to amplify the ColE1/pBR322 origin of replication by polymerase chain reaction amplification. The polymerase chain reaction product DNA was analyzed by dot blot hybridization with HPV-16, -18, -31, or pRB322 DNA probes. Total cellular DNA was also analyzed by one- and two-dimensional Southern blot analysis. Finally, the E6/E7 polymerase chain reaction products were cloned, sequenced, and compared to previously cloned HPV types. RESULTS: Polymerase chain reaction/dot blot analysis by both the HPV E6-E7 and L1 primer sets identified the same 6 out of 17 (35%) breast cancers as being HPV positive. ColE1/pBR322 origin targeted polymerase chain reaction/dot blot analysis failed to identify plasmid contamination. One- and two-dimensional Southern blot analysis showed that the breast cancers specimens contained significant levels of HPV DNA and that the viral DNA was largely episomal. The sequences of the HPV clones demonstrated that HPV-16, -18, and possibly type 11 were present within the breast cancer specimens. Furthermore, the HPV sequences cloned from the cervical swab and breast cancer of the same patient were found to be identical. CONCLUSIONS: These data suggest that HPV may be associated with a significant subset of breast cancers, and further suggest that additional studies are warranted.

Breast Neoplasms↗