Plasma somatostatin-like immunoreactivity during growth-hormone-releasing hormone therapy in non-growth-hormone-deficient children

To date, the effects of long-term growth hormone (GH)-releasing hormone [GHRH(1-29)-NH2] treatment on the plasma concentrations of somatostatin-like immunoreactivity (SLI) remain undefined. In the present study, the effect of GHRH(1-29)-NH2 therapy on plasma SLI levels has been studied in 11 non-GH-deficient children. The pattern of administration was 5 micrograms/kg body weight, given subcutaneously once every day. There was no significant change in plasma SLI levels after bolus injection of GHRH(1-29)-NH2 before and during GHRH(1-29)-NH2 therapy. However, plasma SLI rose in basal plasma and nocturnal sleep after 3 months of GHRH(1-29)-NH2 therapy and remained the same during 6 months of treatment with GHRH(1-29)-NH2. The reason for this finding is uncertain, but an increase in SLI release from the enteroinsular axis is a possible explanation. The association of our findings with the role of the circulating SLI on nutrient homeostasis and the effects of GNRH on growth velocity is discussed.     

PYCNOGENOL chewing gum minimizes gingival bleeding and plaque formation.

PYCNOGENOL is an antioxidant phytochemical shown to have antiinflammatory activity in both the in vitro and in vivo models. This study compared the effects of chewing gums with and without PYCNOGENOL on gingival bleeding and plaque formation in 40 human subjects. In this double-blind study, subjects were assigned randomly to receive either control gums without PYCNOGENOL or experimental gums containng 5 mg PYCNOGENOL. Subjects used chewing gums for 14 days. Gingival bleeding and plaque scores were taken before and after the experiment. PYCNOGENOL chewing gums significantly reduced gingival bleeding, while no changes were noted in bleeding indexes in control subjects who used regular chewing gums. Subjects using regular control gums had significant increases of dental plaque accumulation during the two-week period. No increases in plaque accumulation were noted in subjects using PYCNOGENOL chewing gums. The data of this study suggest that the use of Pycnogenol chewing gums can minimize gingival bleeding and plaque accumulation.     

Spauligodon carbonelli n. sp. (Nematoda: Pharyngodonidae), parasite of some lizards (Lacertidae) in the Iberian Peninsula

Spauligodon carbonelli n. sp. (Nematoda: Pharyngodonidae), a parasite from the caecum of the common wall lizard Podarcis muralis (Laurenti, 1768) and the Spanish wall lizard Podarcis hispanica (Steindachner, 1870) (Reptilia: Lacertidae) in the Pirineos Mountains, Spain, is described. S. carbonelli differs from the other known species of the same genus, mainly in the presence and length of the spicule, the morphology of the caudal end in the male and in the structure of the cephalic end of the female.     

Respiratory response to chemical stimuli and exercise capacity under conditions of acute hypoxia in elite mountain climbers]

To investigate the factors that modulate exercise performance at extreme altitude, the role of the following variables was analyzed in 16 climbers: 1) ventilatory response to chemical stimuli (hypoxia and hypercapnia); and, 2) maximum exercise performance while breathing room air and during acute hypoxia (F1O2, 0.11). Seven climbers (elite climbers, AE) had previously ascended to 8,000 m or more above sea level, and 9 (A) had never achieved such extreme altitude. Then healthy sedentary subjects (C) of similar age (31.1 +/- 6.0 SD years) were used as control group. Elite climbers showed higher ventilatory responses to both transient hypoxia (-0.49 +/- 0.13 L x min-1 x %-1) (p less than 0.05) and progressive hypoxia (-0.47 +/- 0.13 L x min-1 x %-1) than C (-0.33 +/- 0.14 and -0.30 +/- 0.15 L x min-1 x %-1, respectively). By contrast, no differences were observed between the two groups of climbers. The ventilatory response to hypercapnia was higher in AE (3.04 +/- 1.03 L x min-1 mmHg-1) compared to A (1.85 +/- 0.73 L x min-1 mmHg-1) (p less than 0.05) but similar to that observed in C. Breathing 11% O2, maximum workload and oxyhemoglobin desaturation during maximum exercise were similar in both groups of climbers. Additionally, the ventilatory response to hypoxia did not correlate with maximum workload (F1O2, 0.11), maximal ventilation during exercise (F1O2, 0.11), nor with the altitude score. The present study supports previous reports that inform about the role of the ventilatory response to hypoxia in the exercise performance at high altitude.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dissociation of maximal O2 uptake from O2 delivery in canine gastrocnemius in situ

To test the hypothesis that maximal O2 uptake (VO2max) can be limited by O2 diffusion in the peripheral tissue, we kept O2 delivery [blood flow X arterial O2 content (CaO2)] to maximally contracting muscle equal between 1) low flow-high CaO2 and 2) high flow-low CaO2 conditions. The hypothesis predicts, because of differences in the capillary PO2 profile, that the former condition will result in both a higher VO2max and muscle effluent venous PO2 (PVO2). We studied the relations among VO2max, PVO2, and O2 delivery during maximal isometric contractions in isolated, in situ dog gastrocnemius muscle (n = 6) during these two conditions. O2 delivery was matched by varying arterial O2 partial pressure and adjusting flow to the muscle accordingly. A total of 18 matched O2 delivery pairs were obtained. As planned, O2 delivery was not significantly different between the two treatments. In contrast, VO2max was significantly higher [10.4 +/- 0.5 (SE) ml.100 g-1.min-1; P = 0.01], as was PVO2 (25 +/- 1 Torr; P less than 0.01) in the low flow-high CaO2 treatment compared with the high flow-low CaO2 treatment (9.1 +/- 0.4 ml.100 g-1.min-1 and 20 +/- 1 Torr, respectively). The rate of fatigue was greater in the high flow-low CaO2 condition, as was lactate output from the muscle and muscle lactate concentration. The results of this study show that VO2max is not uniquely dependent on O2 delivery and support the hypothesis that VO2max can be limited by peripheral tissue O2 diffusion.     

Quantitative phenotypical expression of three mutant genes in barley and the basis for defining an ideotype for Mediterranean environments

Summary Three mutants induced in the two-rowed barley variety Beka and their three binary recombinants have been used in an attempt to define an ideotype suitable for Mediterranean agroclimatic conditions. Physiological methods (classical plant growth analysis) together with the study of genotype x environment interaction for grain yield were used to characterize the genotypes. That characterization brought out the huge phenotypical variation produced by only three mutant genes, suggesting that single Mendelian genes may alone explain the quantitative variation, including grain yield, without the necessity of using the polygenic concept. The genotype best adapted to the environments studied is later in heading and has shorter straw and denser spikes than Beka; it also has higher inverse of leaf area rate and grain: leaf area ratio, a lower rate of leaf senescence, and a shorter grain filling period than the original variety.     

In vitro penetration assay of boar sperm fertility: effect of various factors on the penetrability of immature pig oocytes

The present study was designed 1) to examine the influence of cumulus cells, ovary storage time and oocyte size on the penetrability of immature pig oocytes, and 2) to investigate the effect of 2 methods of treating the semen from different boars on the inter-assay variability of homologous in vitro penetration tests of boar sperm fertility. In Experiment 1, cumulus oocyte complexes, oocytes with spontaneous loss of the cumulus cells during collection, and oocytes mechanically stripped of cumulus cells were used. No differences were observed in oocyte penetrability among the 3 types of oocyte, although mechanical removal of the cumulus caused an increase (P < 0.005) in the degeneration rate compared with the other oocyte types. In Experiment 2, the oocytes were recovered from ovaries kept in PBS (30 degrees C) for 2, 4 or 6 h after slaughter of prepuberal gilts. Ovary storage did not modify the penetrability of oocytes but increased (P < 0.02) their degeneration rates. In Experiment 3, the diameters of fresh oocytes were determined after co-incubation with spermatozoa. They were classified into 4 groups according to diameter: A) < 105 microm, B) 105-115 microm, C) 116-120 microm and D) > 120 microm. Oocytes from Groups C and D exhibited higher (P < 0.05) penetrability than oocytes from the other groups. In Experiment 4, stored, diluted spermatozoa from 4 boars were pretreated by centrifugation at 50 x g for 3 min and subsequent concentration of the supernatants at 1,200 x g for 3 min. The pellets were treated (washed twice and preincubated for 40 minutes) before co-incubation with immature oocytes or used directly as untreated samples (unwashed and non-preincubated). A boar effect (P < 0.001) was evident for the parameters of in vitro penetration, independently of sperm treatment. When the oocytes were inseminated with untreated spermatozoa, the effects of the replicate and the boar-by-replicate interaction on the variability in oocyte penetrability were not significant. The results of this study indicate that the use of standardized immature pig oocytes and stored untreated, diluted spermatozoa can provide a useful method for optimizing the homologous in vitro penetration (hIVP) assay of boar fertility.     

Xylitol production by immobilized recombinant Saccharomyces cerevisiae in a continuous packed-bed bioreactor

Continuous xylitol production with two different immobilized recombinant Saccharomyces cerevisiae strains (H475 and S641), expressing low and high xylose reductase (XR) activities, was investigated in a lab-scale packed-bed bioreactor. The effect of hydraulic residence time (HRT; 1.3-11.3 h), substrate/cosubstrate ratio (0.5 and 1), recycling ratio (0, 5, and 10), and aeration (anaerobic and oxygen limited conditions) were studied. The cells were immobilized by gel entrapment using Ca-alginate as support and the beads were treated with Al(3+) to improve their mechanical strength. Xylose was converted to xylitol using glucose as cosubstrate for regeneration of NAD(P)H required in xylitol formation and for generation of maintenance energy. The stability of the recombinant strains after 15 days of continuous operation was evaluated by XR activity and plasmid retention analyses. Under anaerobic conditions the volumetric xylitol productivity increased with decreasing HRT with both strains. With a recycling ratio of 10, volumetric productivities as high as 3.44 and 5.80 g/L . h were obtained with the low XR strain at HRT 1.3 h and with the high XR strain at HRT 2.6 h, respectively. However, the highest overall xylitol yields on xylose and on cosubstrate were reached at higher HRTs. Lowering the xylose/cosubstrate ratio from 1 to 0.5 increased the overall yield of xylitol on xylose, but the productivity and the xylitol yield on cosubstrate decreased. Under oxygen limited conditions the effect of the recycling ratio on production parameters was masked by other factors, such as an accumulation of free cells in the bioreactor and severe genetic instability of the high XR strain. Under anaerobic conditions the instability was less severe, causing a decrease in XR activity from 0.15 to 0.10 and from 3.18 to 1.49 U/mg with the low and high XR strains, respectively. At the end of the fermentation, the fraction of plasmid bearing cells in the beads was close to 100% for the low XR strain; however, it was significantly lower for the high XR strain, particularly for cells from the interior of the beads. (c) 1996 John Wiley & Sons, Inc.     

Inheritance of random amplified polymorphic DNA markers in cassava (Manihot esculenta Crantz)

The informativeness and inheritance of randomly amplified polymorphic DNA (RAPD) markers were investigated in an intraspecific F1 progeny derived from two heterozygous parents. The analysis confirmed the utility of RAPD markers for comparing candidate parents for the development of a molecular genetic map, and provided numerous markers for linkage analysis in a crop with a very limited history of classical or molecular genetic studies. Six potential parental lines (themselves F1 hybrid clones) showed between 1.82 and 0.62 segregating bands per primer in three hybrid families. Forty-three percent (309) of 722 primers produced polymorphic products in the most informative of these three crosses, revealing 328 single-dose (SD) markers segregating 1:1 for presence/absence in a progeny of 90 individuals. A second class of informative markers were those present in both parents but segregating in the progeny. Fifty-seven or 67% of the monomorphic but segregating markers exhibited the 3:1 ratio expected for SD dominant markers in a cross between heterozygotes. Linkage groups were constructed from the segregation of SD RAPD markers originating in the female (TMS 30572) and the male (CM2177-2) parent. Key words : RAPDs, molecular markers, genetic segregation, Manihot, single-dose markers.     

Sperm concentration influences fertilization and male pronuclear formation in vitro in pigs

To study the effect of sperm concentration on the results of pig in vitro fertilization (IVF), 313 oocytes recovered from oviducts of prepubertal gilts after induction of ovulation were used. After capacitation, the number of live spermatozoa in the fertilization dishes was adjusted to 3 x 10(5), 6 x 10(5) and 12 x 10(5) cell/ml. After 4 hours of co-culture in TCM-199, the oocytes were pippeted to remove cumulus cells and the excess spermatozoa around the zona pellucida, and were transferred to fresh TCM-199 for another 12 14 hours . The results showed that 6 x 10(5) spermatozoa/ml is the optimum concentration for this system; the percentage of fertilized ova (71.6%) was not different from the best (76.8%), that was obtained with the highest concentration, and the percentage of monospermy (62.3%) was not different from the best (68.1%), that was obtained with the lowest concentration. The percentage of spermatozoa that reached the pronuclear stage increased while sperm concentration was decreased. The percentage of spermatozoa at the decondensed stage was decreased when the sperm concentration increased.