Effect of copper, zinc, and manganese supplementation and source on reproduction, mineral status, and performance in grazing beef cattle over a two-year period.

Crossbred, multiparous beef cows (n = 178 in Year 1; n = 148 in Year 2) were used to evaluate the effects of Cu, Zn, and Mn supplementation and source on reproduction, mineral status, and performance in grazing cattle in eastern Colorado over a 2-yr period. Cows were stratified by expected calving date, age, BW, BCS, and liver mineral status and assigned to the following treatments: 1) control (no supplemental Cu, Zn, or Mn); 2) organic (ORG; 50% organic and 50% inorganic Cu, Zn, and Mn); and 3) inorganic (ING; 100% inorganic CuSO4, ZnSO4, and MnSO4). Free-choice mineral feeders were used to provide current NRC-recommended concentrations of Cu, Zn, and Mn from 82 d (Year 1) and 81 d (Year 2) before the average calving date of the herd through 110 d (Year 1) and 135 d (Year 2) after calving. At the end of Year 1, supplemented cows had greater liver Cu (P < 0.01), Zn (P < 0.05), and Mn (P < 0.01) concentrations compared with controls, whereas liver Cu concentration was greater (P < 0.01) in ORG vs. ING cows. At the end of Year 2, supplemented cows had greater (P < 0.01) liver Cu concentrations relative to controls, whereas control cows had greater (P < 0.02) liver Mn concentration than did supplemented cows. In Year 1, pregnancy rate to AI in control cows did not differ (P = 0.47) from supplemented cows, but there was a trend (P < 0.08) for pregnancy rate to be higher for ORG than ING cows. In Year 2, supplemented cows had a higher (P < 0.02) pregnancy rate to AI than controls. In both years, when cows were inseminated after an observed estrus, supplemented cows had a higher (P < 0.04) pregnancy rate than did controls. Also, for both years, overall 60-d pregnancy rate tended (P = 0.10) to be higher for supplemented cows than for controls. In Year 1, kilograms of calf weaned per cow exposed was greater (P < 0.02) in controls than in supplemented cows, and kilograms of calf weaned per cow exposed was greater (P < 0.01) in ING than ORG treatments. However, in Year 2, kilograms of calf weaned per cow exposed was greater (P < 0.02) in controls than in supplemented cows, and tended (P = 0.09) to be greater in ORG than ING treatments. Results indicate that supplementation and source of trace minerals affected mineral status and kilograms of calf weaned per cow exposed in grazing beef cows. Supplementation also improved pregnancy rate to AI compared with cows not supplemented with Cu, Zn, or Mn for more than 1 yr. Furthermore, mineral source may influence pregnancy rate to AI.

Use of control analysis to study the regulation of plant lipid biosynthesis.

Control analysis is a powerful method to quantify the regulation of metabolic pathways. We have applied it to lipid biosynthesis for the first time by using model tissue culture systems from the important oil crops, olive ( Olea europaea L.) and oil palm ( Elaeis guineensis Jacq.). By the use of top-down control analysis, fatty acid biosynthesis has been shown to exert more control than lipid assembly under different experimental conditions. However, both parts of the lipid biosynthetic pathway are important, so that attempts to alter oil yield by manipulating the activity of a single enzyme step are very unlikely to produce significant increases.

Pharmacokinetics, metabolism, and excretion of irinotecan (CPT-11) following I.V. infusion of [(14)C]CPT-11 in cancer patients.

This study determined the disposition of irinotecan hydrochloride trihydrate (CPT-11) after i.v. infusion of 125 mg/m(2) (100 microCi) [(14)C]CPT-11 in eight patients with solid tumors. Mean +/- S.D. recovery of radioactivity in urine and feces was 95.8 +/- 2.7% (range 92.2-100.3%, n = 7) of dose. Radioactivity in blood, plasma, urine, and feces was determined for at least 168 h after dosing. Fecal excretion accounted for 63.7 +/- 6.8 (range 54.2-74.9%, n = 7) of dose, whereas urinary excretion accounted for 32.1 +/- 6.9% (range 21.7-43.8%; n = 7) of dose. One patient with a biliary T-tube excreted 30.1% of dose in bile, 14.2% in feces, and 48.2% in urine. Quantitative radiometric HPLC revealed that CPT-11 was the major excretion product in urine, bile, and feces. Aminopentane carboxylic acid (APC) and SN-38 glucuronide (SN-38G) were the most significant metabolites in urine and bile, whereas SN-38 and NPC, a primary amine metabolite, were relatively minor excretion products. SN-38 and APC were the most significant metabolites in feces. The relatively higher amount of SN-38 in feces compared with bile is presumably due to hydrolysis of SN-38G to SN-38 by enteric bacterial beta-glucuronidases. There was close correspondence between quantitative fluorescence HPLC and mass balance findings. CPT-11 was the major circulating component in plasma (55% of the mean radiochemical area under the curve), and CPT-11, SN-38, SN-38G, and APC accounted for 93% of the mean radiochemical AUC. These results show that the parent drug and its three major metabolites account for virtually all CPT-11 disposition, with fecal excretion representing the major elimination pathway.

Use of the carbon dioxide laser in the drainage of subretinal fluid.

Hemorrhage and retinal perforation are two sight-threatening complications associated with techniques employed to drain subretinal fluid in rhegmatogenous retinal detachment. We hypothesized that the carbon dioxide (CO2) laser would reduce these complications because of its cauterizing action and high absorption in water. The CO2 laser was compared with a conventional technique of using a penetrating diathermy electrode to drain subretinal fluid in rabbits with experimentally detached retinas. No hemorrhage occurred in 223 drainage trials using the CO2 laser, whereas hemorrhage occurred in 21 (4.8%) of 434 trials using the penetrating diathermy electrode. Furthermore, a depth of saline of only 45 microns protected the retina from perforation at CO2 laser dose adequate for drainage. These results indicate that further evaluation of the CO2 laser in treating human retinal detachment is warranted.

Vitreoperfusion. A new approach to ocular ischemia.

No satisfactory treatment is available to supply the metabolic needs of the retina in vascular occlusion. Consequently, necrosis occurs. We devised vitreoperfusion, a technique of perfusing the vitreous cavity after vitrectomy-lensectomy with selected fluids containing glucose and oxygen. We tested whether vitreoperfusion could protect the retina from severe combined retinal and choroidal ischemia. An intraocular pressure of 170 mm Hg was induced in each eye of nine cats for up to four hours, and simultaneously one eye of each cat underwent vitreoperfusion. After one week, histopathologic examination revealed retinal atrophy and dissolution in untreated eyes but not in eyes treated with vitreoperfusion. To our knowledge, such severe ischemia has never been treated successfully before. Vitreoperfusion is a potential treatment modality in various forms of ocular ischemia. Additional studies are warranted to refine the technique and determine any clinical applicability.

Comparison of collagen degradation and synthesis in the peripheral and central areas of experimental corneal grafts.

The distribution of collagen degradation and synthesis (turnover) between the central and peripheral areas of clear corneal allografts was determined, following transplantation of 6-mm [3H]proline-labelled corneal buttons from extensively pre-labelled, young rabbits into 13 nonradioactive mature rabbits. Control, contralateral 6-mm corneal buttons of each radioactive pair were frozen at -70 degrees C after being trephined into a central 3-mm button and a peripheral ring of cornea. The grafts were removed 10-100 days after the operation and trephined similarly to the paired controls. The central and peripheral areas of the graft and control corneal buttons were analysed separately for total hydroxyproline and radioactivity. A significant degradation of old collagen (as seen by the loss of total radioactivity) occurred early in both the central (19.4 +/- 6.1%) and peripheral (12.3 +/- 7.5%) areas of the grafted corneas, compared to the corresponding areas of the contralateral controls. A significant increase in new, non-radioactive collagen occurred in both the central (22.0 +/- 7.6%) and peripheral areas (30.6 +/- 6.1%); however, a significant net increase in total collagen occurred only in the peripheral area (18.3 +/- 11.4). Loss of original (old) collagen was significantly greater in the central area than in the peripheral area; whereas, the increase in new collagen was significantly greater in the peripheral area than the central area, accounting for a significant increase in total collagen. There was no correlation in collagen turnover with time after surgery. Collagen turnover occurs acutely throughout the clear corneal graft and thereafter is stable.

The little finger superficialis--clinical investigation of its anatomic and functional shortcomings.

Based on clinical experience in the treatment of isolated injury to the little finger profundus tendon, we hypothesized that the little finger superficialis is functionally deficient in a significant portion of the population. Five hundred twenty-six normal hands were examined using the standard superficialis test and a subset of two hundred four normal hands were again examined using a modified superficialis test. We found that 33.8% of the little finger superficialis tendons in the normal population could not achieve normal range of flexion at the proximal interphalangeal joint (PIP) when submitted to the standard superficialis test. When the ring finger was allowed to flex along with the little finger, many of the previously deficient appearing fingers achieved near normal PIP joint flexion; however, 15.7% of the population still showed significant superficialis deficiency in the little finger. This portion of the population risks complete loss of flexion at both interphalangeal joints in the event of isolated profundus disruption in the little finger.