Gonadotropin releasing hormone treatment of dairy cows with ovarian cysts. I. Gross ovarian morphology and endocrinology

Dairy cows diagnosed as having ovarian cysts were assigned to receive either sterile water or 100 mug GnRH (5 cows/group). Immediately prior to treatment and three days post-treatment, ovaries were observed via paralumbar laparotomy, photographed and visible structures and ovarian size recorded. Nine to thirteen days post-treatment, ovaries were removed. Blood plasma was collected for hormone determinations prior to each surgery, 1.5 and 3.0 hours and 1, 5 and 9 days post-treatment. Although concentrations were similar between groups prior to treatment, concentrations of progesterone were higher and LH and estradiol-17beta lower for GnRH treated cows than control cows, immediately prior to ovariectomy. A layer of luteal tissue approximately 5 mm thick was present around the periphery of the cystic structure at ovariectomy in 4 of 5 GnRH treated cows, but in only one control cow. The thickness of the luteal layer around the periphery of the ovarian cysts was correlated -.82, .78 and -.63 with estradiol-17beta, progesterone and LH, respectively. In summary, response to GnRH treatment in cows with ovarian cysts appears to be characterized in most cases by luteinization of the cystic structures.     

Carbohydrate metabolism during cold-induced sweetening of potato tubers

The aim of this work was to discover the effects of lowering the temperature from 25° to 2° on the metabolism of glucose [U-¹⁴C] by tubers of Solanum tuberosum. Isotope was applied to tubers via a 50-μl hole made with a capillary pipette. Tubers were incubated for 2 hr, the pulse; then the glucose- [U-¹⁴C] was replaced with glucose, and incubation was continued for 18 hr, the chase. The detailed distribution of ¹⁴C was determined at the end of the pulse and at the end of the chase at 2°, and compared with those found at 25°. Lowering the temperature reduced the proportion of metabolized ¹⁴C that entered the respiratory pathways. At 2°, but not at 25°, hexose phosphates were the most heavily labelled fraction after the pulse: during the chase at 2° much of this label was metabolized to sucrose. We conclude that lowering the temperature preferentially restricts glycolysis and diverts hexose phosphates to sucrose. We suggest that this is an important cause of cold-inducing sweetening of the tubers and is due to cold-lability of key glycolytic enzymes.     

Photosynthesis in Grass Species Differing in Carbon Dioxide Fixation Pathways: III. OXYGEN RESPONSE AND ENZYME ACTIVITIES OF SPECIES IN THE LAXA GROUP OF PANICUM

Measurements of CO₂ exchange at varying O₂ concentrations in seven grass species of the Laxa group of Panicum and activities of five photosynthetic enzymes were compared to values obtained for these characters in a cool season C₃ grass, tall fescue (Festuca arundinacea Schreb.) and a C₄ grass, P. maximum Jacq. Plants were divided into three groups on the basis of the inhibition of apparent photosynthesis by 21% O_2. Rates of apparent photosynthesis in P. prionitis Griseb. and P. maximum were virtually unaffected by changes in O₂ concentration. In another group consisting of P. hylaeicum Mez., P. rivulare Trin., P. laxum Sw., and tall fescue apparent photosynthesis was inhibited by 28.2 to 36.0% at 21% O_2. An intermediate inhibition of 20.6 to 23.3% at 21% O₂ was exhibited by P. milioides Nees ex Trin., P. schenckii Hack., and P. decipiens Nees ex Trin. The CO₂ compensation concentration for P. prionitis and P. maximum was low (≤6 microliters per liter CO₂ at 21% O₂) and affected little by O₂, whereas values for P. hylaeicum, P. rivulare, P. laxum, and tall fescue were much greater, and increased almost linearly from 2 to 48% O_2. Values for P. milioides, P. schenckii, and P. decipiens were intermediate to the other two groups. The effect of O₂ on total leaf conductance to CO₂ was similar to the C₃ grasses and the intermediate Panicums. However, estimates of photorespiration in the intermediate species were low and changed little with O₂ in comparison to estimates for the C₃ species which were higher and increased greatly with increased O_2.     

Photosynthesis of Grass Species Differing in Carbon Dioxide Fixation Pathways: IV. ANALYSIS OF REDUCED OXYGEN RESPONSE IN PANICUM MILIOIDES AND PANICUM SCHENCKII

Reduced photorespiration has been reported in Panicum milioides on the basis of lower CO₂ compensation concentrations than in C₃ species, lower CO₂ evolution in the light, and less response of apparent photosynthesis to O₂ concentration. The lower response to O₂ in P. milioides could be due to reduced O₂ competition with CO₂ for reaction with ribulose 1,5-bisphosphate, to a reduced loss of CO₂, or to an initial fixation of CO₂ by phosphoenolpyruvate carboxylase. Experiments were carried out with Panicum maximum Jacq., a C₄ species having no apparent photorespiration; tall fescue (Festuca arundinacea Schreb.), a C₃ species; P. milioides Nees ex Trin.; and Panicum schenckii Hack. The latter two species are closely related and have low photorespiration rates. CO₂ exchange was measured at five CO₂ concentrations ranging from 0 to 260 microliters per liter at both 2 and 21% O₂. Mesophyll conductance or carboxylation efficiency was estimated by plotting substomatal CO₂ concentrations against apparent photosynthesis. In the C₄ species P. maximum, mesophyll conductance was 0.96 centimeters per second and was unaffected by O₂ concentration. At 21% O₂ mesophyll conductance of tall fescue was decreased 32% below the value at 2% O₂. Decreases in mesophyll conductance at 21% O₂ for P. milioides and P. schenckii were similar to that for tall fescue. On the other hand, loss of CO₂ in CO₂-free air, estimated by extrapolating the CO₂ response curve to zero CO₂, was increased from 1.8 to 6.5 milligrams per square decimeter per hour in tall fescue as O₂ was raised from 2-21%. Loss of CO₂ was less than 1 milligram per square decimeter per hour for P. milioides and P. schenckii and was unaffected by O₂. The results suggest that the reduced O₂ response in P. milioides and P. schenckii is due to a lower loss of CO₂ in the light rather than less inhibition of carboxylation by O₂, since the decrease in carboxylation efficiency at 21% O₂ was similar for P. milioides, P. schenckii, and tall fescue. The inhibition of apparent photosynthesis by 21% O₂ in these three species at low light intensities was similar at 31 to 36% which also indicates similar O₂ effects on carboxylation. Apparent photosynthesis at high light intensity was inhibited less by 21% O₂ in P. milioides (16.8%) and P. schenckii (23.8%) than in tall fescue (28.4%). This lower inhibition in the Panicum species may have been due to a higher degree of recycling of photorespired CO₂ in these species than in tall fescue.     

Photosynthesis of Grass Species Differing in Carbon Dioxide Fixation Pathways: V. RESPONSE OF PANICUM MAXIMUM, PANICUM MILIOIDES, AND TALL FESCUE (FESTUCA ARUNDINACEA) TO NITROGEN NUTRITION

The response of apparent photosynthesis to N nutrition was studied in the C₃ grass, tall fescue (Festuca arundinacea Schreb.), in the C₄ species Panicum maximum Jacq., and in Panicum milioides Nees ex Trin., a species with characteristics intermediate between C₃ and C₄ photosynthetic types. Plants were grown in culture solution containing 1, 5, 50, and 200 milligrams N per liter. Apparent photosynthesis was measured on the youngest fully expanded leaves at 320 microliters of CO₂ per liter of air and 21% O₂. Leaf conductance was calculated from transpiration measurements, and CO₂ compensation concentrations were also estimated. Several leaf anatomical characteristics were studied on plastic-embedded material. Leaf N content was determined on leaves which were used in photosynthesis measurements.     

Vitamin D supplements in pregnant Asian women: effects on calcium status and fetal growth.

In a double-blind trial of vitamin D supplements in pregnant Asian women calciferol (ergocalciferol, 1000 IU/day) was administered to 59 women and placebo to 67 controls during the last trimester. The two groups had similar distributions of maternal age, height, parity, number of vegetarians, countries of origin, and sex and gestation of the infants. At entry to the trial maternal serum 25-hydroxy vitamin D (25-OHD) concentrations were low in both treatment and control groups and significantly lower in vegetarians than non-vegetarians. Mothers in the treatment group gained weight faster in the last trimester than those in the control group, and at term they and their infants all had adequate plasma 25-OHD concentrations, Mothers and infants in the control group, however, had low plasma concentrations of 25-OHD and calcium and raised plasma alkaline phosphatase (bone isoenzyme) activity. Five of these infants developed symptomatic hypocalcaemia. Almost twice as many infants in the control group were small for gestational age (29% v 15%), but there were no significant differences between the two groups of infants in antropometric measurements. Infants in the control group, however, had larger fontanelles, suggesting impaired ossification of the skull. Because of the benefits to mothers and infants in the treatment group and the absence of side effects, vitamin D supplements should be given to all pregnant Asian women in the United Kingdom.     

Comparison of high-performance liquid chromatographic serum profiles of humans and dogs

The sera of 30 healthy male beagles were analyzed by reversed-phase high-performance liquid chromatography. The profiles were compared with those obtained from the sera of 30 healthy human donors. The chromatograms of each group were very reproducible; however, there were characteristic differences between the two groups. The compounds observed in both the human and canine profiles were identified as creatinine, uric acid, tyrosine, hypoxanthine, xanthine, kynurenine, inosine and tryptophan. Compounds present only in the canine profiles were identified as cytindine, riboflavin and 5-methylcytidine. Compounds present only in the human profiles include uridine, guanosine, hippuric acid and the dietary dependent compounds theobromine and caffeine. The compounds present in both human and canine sera were quantitated and compared statistically. The amounts of these compounds were very similar, except for uric acid.     

Waterborne transmission ofCampylobacter enteritis

Campylobacter jejuni is an important cause of human diarrheal disease throughout the world and likeSalmonella enteritidis, has a large animal reservoir which includes most of man's domestic animals. Until recently, it has been difficult to trace the chain of transmission from animals to man because of inadequate environmental sampling techniques and means to distinguish strains. Recent improvements in these techniques have made environmental studies more feasible in 2 water-related out-breaks.In 1 study,C. jejuni was found to be an important cause of sporadic, summertime diarrheal disease among hikers in national wilderness areas of Wyoming. In this setting, illness was significantly associated with drinking untreated surface water. SubsequentlyC. jejuni was isolated from surface water, including mountian streams, and from animals in the area. Some of the environmental isolates were serotypically identical to strains isolated from humans.A second study occurred as a result of an outbreak of Campylobacter enteritis in a community in northern Illinois which was epidemiologically associated with the community water system.Campylobacter jejuni was isolated from several surface water sources and from the implicated water system. These studies demonstrate that environmental isolation ofC. jejuni is now possible and may add to our understanding of disease transmission.     

Evidence that calmodulin may be involved in phytohaemagglutinin-stimulated lymphocyte division

Phytohaemagglutinin-stimulated and non-stimulated incorporation of [³H]thymidine into human peripheral blood lymphocytes is inhibited by the calcium antagonist PY 108–068 and by the calmodulin antagonists trifluo-perazine andN-(6-aminohexyl)-5-chloro-l-naphthalene sulphonamide (W7). It is argued that calmodulin may be involved in both non-stimulated [³H]thymidine uptake in lymphocytes and also in the lymphocyte response to phytohaemagglutinin.     

Location and orientation relative to the micelle surface for glucagon in mixed micelles with dodecylphosphocholine EPR and NMR studies

The spin labels, 5-doxylstearate, 12-doxylstearate, 16-doxylstearate and 1-oxyl-2,2,6,6-tetramethyl-4-dodecylphospiperidine, have been incorporated into dodecylphospocholine micelles and mixed dodecylphosphocholine/ glucagon micelles. The EPR spectral parameters for the different spin labels and the ¹H- and ¹³C-NMR relaxation rates for nuclei of the detergent molecules indicated that inclusion of up to one spin label molecule per micelle had little influence on the spatial organization of the micelles. Furthermore, the location and environment of the spin labels in the dodecylphosphocholine micelles were not noticeably affected by the addition of glucagon and the ¹H-NMR spectra observed for glucagon in mixed spin label/deuterated dodecylphosphocholine/glucagon micelles showed that the different spin labels had essentially no effect on the conformation of glucagon. Approximate spatial locations within the micelle for the nitroxide moieties of the different spin labels were determined from the NMR relaxation rates observed for different nuclei of dodecylphosphocholine. On this basis, the line broadening of individually assigned glucagon ¹H-NMR lines by the different spin labels was used to determine the approximate orientation of the polypeptide chain with respect to the micelle surface. Overall, the data indicate that the glucagon backbone runs roughly parallel to the micelle surface, with the depth of immersion adjusted so that polar and apolar side chains can be oriented towards the surface or interior of the micelle, respectively.