The effect of coencapsulation of bovine insulin with cyclodextrins in ethylcellulose microcapsules.

Polymeric microcapsules have been widely investigated for protein delivery. Common problems include: low stability, low encapsulation efficiency, lack of uniformity, and burst release. Cyclodextrins (CDs) are known to enhance stability and solubility of proteins in solution. This research examines the effect of alpha-, beta-, and gamma-CDs on: (1) stability, (2) encapsulation, and (3) release of insulin from ethylcellulose microcapsules. All CDs improved thermal stability of insulin by lowering the enthalpy of unfolding by 16-52%. alpha- and gamma-CDs also increased the encapsulation efficiency of insulin and improved uniformity of the microcapsule formulations. Two mathematical models were proposed to account for insulin release and consisted of multiple zero order and first order input processes, and a single first order output process. All CDs decreased the initial burst release of insulin by up to 30%. This research demonstrates the potential for CDs to improve stability, uniformity, and encapsulation of proteins in microcapsule formulations.

Effects of commonly used cooking practices on total mercury concentration in fish and their impact on exposure assessments.

The effects of cooking practices commonly used by Native Americans on total mercury concentrations in fish were investigated. A preparation factor relating mercury concentrations in fish as prepared for consumption to mercury concentration data as measured in typical environmental monitoring programs was calculated. Preparation factors are needed to provide risk assessors with a more accurate estimate of the actual amount of mercury ingested through consumption of contaminated fish. Data on fish preparation and consumption practices of two communities of Chippewa residing on the shores of Lake Superior in northern Wisconsin were used to select practices for study. The most commonly consumed species, walleye and lake trout, were selected. Whitefish livers were also selected for study. Commonly used cooking techniques including panfrying, deep-frying, baking, boiling, and smoking were duplicated in the laboratory. Total mercury concentrations were determined in fish portions before and after cooking and in a portion representative of that analyzed in programs to assess water quality (skin-on fillets). Total mercury was determined by microwave digestion-cold vapor atomic absorption spectroscopy. Mercury concentrations (wet weight basis) in panfried, baked, and boiled walleye fillets and deep-fried and baked whitefish livers ranged from 1.1 to 1.5 times higher than in corresponding raw portions. In lake trout, mercury concentrations were 1.5 to 2.0 times higher in cooked portions than in the raw portion. However, total mercury levels were constant before and after cooking, indicating the concentration effect is caused by weight (moisture and fat) loss. The addition of lemon juice to potentially release mercury from its bound state and promote volatilization did not exert any measurable influence on mercury concentrations in cooked walleye. In some cases mercury concentrations were increased with increased cooking times due to further loss of moisture and fat. Preparation factors (defined as the ratio of mercury concentration in cooked fish to the mercury concentration in the environmental portion) ranged from 1.3 to 2.0. Results suggest that consideration be given to the use of preparation factors in risk assessments, exposure assessments, or issuance of fish advisories where mercury concentration in raw fish tissue are used in conjunction with cooked fish meal sizes.

Factors influencing estrus and conception in dairy heifers after prostaglandin F2-alpha.

The influence of interval between insemination (AI) and estrus on subsequent fertility of PGF2alpha-treated (two injections of 25 mg, 11 days apart) heifers was assessed in two experiments. In Experiment I, 240 heifers were allotted to Control (AI 8 to 16 hr after estrus detection), PGF2alpha-E (AI 8 to 16 hr after estrus within five days of second PGF2alpha) or PGF2alpha-T (AI 80 hr after second PGF2alpha). In Experiment II, 130 heifers were assigned to control (AI as before) or PGF2alpha (AI 72 or 80 hr after second PGF2alpha) with half the PGF2alpha heifers receiving 100 microg GnRH 72 hr after first PGF2alpha. Heifers of both experiments that were bred at a predetermined time were arrayed by interval from AI to estrus. Conception rates of heifers detected in estrus from 32 hr before AI to 24 hr after AI did not differ (x2=3.35, df=5, P>0.5). The percentage of GnRH-treated heifers in estrus within five days (81.8%) was not (P>0.75) greater than those not receiving GnRH (77.3%) but they had higher (P<0.05) serum progesterone (P4) concentration at second PGF2alpha (3.17 vs 2.41 ng/ml). When P4 values were arrayed for both groups at 1 ng intervals, the percentage of heifers exhibiting estrus increased with increasing P4 level (P<0.05).

Radiology inhouse engineering.

In summary, a brief discussion of the advantages and disadvantages of inhouse radiology engineering has been presented. There are potential dollars to be saved, as well as the possibility of improving the quality of care we provide. If an institution cannot support an engineering program by themselves, a shared program should be considered. As legislation continues to impact imaging, we must consider different ways to accomplish our tasks: inhouse radiology engineering is one program that may warrant investigation.

The mechanism of cytoplasmic orthopoxvirus DNA replication.

Orthopoxvirus DNA replication occurs in the cytoplasm of infected cells within discrete foci designated as virosomes. We show that newly synthesized rabbit poxvirus (RPV) virosomal DNA consists predominantly of concatamers wherein unit length molecules are joined by fusion of two left (LL) or right (RR) ends, resulting in genomes aligned in alternating head-to-head and tail-to tail mirror image arrays. These concatameric molecules serve as the substrates from which unit length DNA molecules are excised during morphogenesis. We propose a mechanism by which internal deletions within these concatameric arrays prior to genome excision and packaging could create inverted terminal repeats and generate gene duplications.

The white pock (mu) mutants of rabbit poxvirus. III. Terminal DNA sequence duplication and transposition in rabbit poxvirus.

The restriction fragment patterns of the DNA of three white pock (mu) nonhost range mutants RPmu mutants) of rabbit poxvirus (RPV) show the presence of net insertions of DNA. Two of the mutants (RPmu21 and RPmu7) contain two molar quantities of 13 X 10(6) and 15 X 10(6) daltons, respectively, of the left-most viral DNA sequences. The extra copy of these sequences was inserted into the right-most region of the viral genome which in both cases had been modified by deletion of 10 X 10(6) daltons of the original extreme right-most DNA sequences. Hence two mutants with "left-hand" mirror image termini of 13 X 10(6) and 15 X 10(6) daltons of DNA were generated with an overall net increase in mass of 3 X 10(6) and 5 X 10(6) daltons of DNA to yield genome molecular weights of 121 X 10(6) and 123 X 10(6) for RPmu21 and 7, respectively. A third mutant (RPmu81g) contained 28 X 10(6) daltons of the right-most parental DNA sequences inserted into the left end of the genome, which had deleted 6 X 10(6) daltons of the extreme left-hand sequences. This variant contains "right-hand" mirror image termini of 28 X 10(6) daltons of DNA and a net increase in molecular weight of 22 X 10(6) daltons of DNA to yield a genome molecular weight of 140 X 10(6). The cross-linked end of the transposed sequences is retained in all cases. Our data suggest that the terminal DNA sequences at either end of the virus are not essential for a productive infection in certain host cells and that the pathogenicity of orthopoxviruses may be related in part to a series of varied and interchangeable DNA sequences located at both extremes of a high conserved genome core.