Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolism

OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.     

7500 years of prehistoric footwear from arnold research cave, missouri

Accelerator mass spectrometer dating of an assemblage of fibrous and leather footwear from Arnold Research Cave in central Missouri documents a long sequence of shoe construction by prehistoric Midwestern peoples, beginning perhaps as early as 8300 calendar years before the present (cal years B.P.). An earlier fibrous sandal form dates from 8325 to 7675 cal years B.P., and later fibrous or leather slip-ons span the period from 5575 to 1070 cal years B.P. The assemblage adds to a growing picture of the highly varied nature of prehistoric footwear production in the United States throughout the Holocene.     

Genesis and evolution of the 1997-98 El Nino

The 1997-98 El Nino was, by some measures, the strongest on record, with major climatic impacts felt around the world. A newly completed tropical Pacific atmosphere-ocean observing system documented this El Nino from its rapid onset to its sudden demise in greater detail than was ever before possible. The unprecedented measurements challenge existing theories about El Nino-related climate swings and suggest why climate forecast models underpredicted the strength of the El Nino before its onset.     

Localization of Insulin‐Like Growth Factor‐I (IGF‐I) and IGF‐I Receptor (IGF‐IR) in Equine Testes

The insulin‐like growth factor‐I (IGF‐I) is a key regulator of reproductive functions. IGF‐I actions are primarily mediated by IGF‐IR. The main objective of this research was to evaluate the presence of IGF‐I and IGF‐I Receptor (IGF‐IR) in stallion testicular tissue. The hypotheses of this study were (i) IGF‐I and IGF‐IR are present in stallion testicular cells including Leydig, Sertoli, and developing germ cells, and (ii) the immunolabelling of IGF‐I and IGF‐IR varies with age. Testicular tissues from groups of 4 stallions in different developmental ages were used. Rabbit anti‐human polyclonal antibodies against IGF‐I and IGF‐IR were used as primary antibodies for immunohistochemistry and Western blot. At the pre‐pubertal and pubertal stages, IGF‐I immunolabelling was present in spermatogonia and Leydig cells. At post‐pubertal, adult and aged stages, immunolabelling of IGF‐I was observed in spermatogenic cells (spermatogonia, spermatocyte, spermatid, and spermatozoa) and Leydig cells. Immunolabelling of IGF‐IR was observed in spermatogonia and Leydig cells at the pre‐pubertal stage. The immunolabelling becomes stronger as the age of animals advance through the post‐pubertal stage. Strong immunolabelling of IGF‐IR was observed in spermatogonia and Leydig cells at post‐puberty, adult and aged stallions; and faint labelling was seen in spermatocytes at these ages. Immunolabelling of IGF‐I and IGF‐IR was not observed in Sertoli cells. In conclusion, IGF‐I is localized in equine spermatogenic and Leydig cells, and IGF‐IR is present in spermatogonia, spermatocytes and Leydig cells, suggesting that the IGF‐I may be involved in equine spermatogenesis and Leydig cell function as a paracrine/autocrine factor.     

Hydrogen peroxide affects plant growth promoting effects of <Emphasis Type="Italic">Azospirillum</Emphasis>

This study aimed to investigate if pretreatment seed with H₂O₂ affects promoting effect of Azospirillum on plant. The experiment was a factorial combination of two main factors, Azospirillum and hydrogen peroxide (0, 25, 50, and 80%), carried out under field conditions. Soaking seed in various concentrations of H₂O₂ solution resulted in enhanced stomata density and increased length and histological components of leaf. These changes in histological components were found to be positive since plants of H₂O₂-soaked seeds (H₂O₂ pretreatment) had higher fresh and dry weights, seed number per spike, and higher grain yield. Azospiriilum enhanced number of grain spikes^-1 and total grain yield by 3% and 7%, respectively. Soaking seeds in 25% H₂O₂ solution enhanced the promoting effect of Azospirillum on increased vessels area and diameter. Soaking seeds in 50% H₂O₂ solution resulted in enhanced stimulating effect of Azospirillum on enhanced areas of vascular bundle and upper epidermis. The promoting effect of Azospirillum on the area of lower epidermis was largest when seed was pretreated with 80% H₂O₂. All three concentrations of H₂O₂ used had the same effect on Azospirillum–inoculated plant in terms of leaf area and chlorophyll a. Soaking seed in 80% H₂O₂ solution and then inoculated with Azospirillum resulted in the highest grain yields.     

Effect of hCG on Early Luteal Serum Progesterone Concentrations in PG600‐Treated Gilts

Gilt oestrus and ovulation responses to injection of a combination of equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG) (PG600) can be unpredictable, possibly reflecting inadequate circulating LH activity. The objective of this study was to determine the effect of PG600 followed by supplemental hCG on gilt ovarian responses. In experiment 1, 212 Hypor gilts (160 day of age) housed on two farms in Spain received intramuscular (i.m.) injections of PG600 (n = 47), or PG600 with an additional 200 IU hCG injected either concurrently (hCG‐0; n = 39), or at 24 h (hCG‐24; n = 41) or 48 h (hCG‐48; n = 45) after PG600. A further 40 gilts served as non‐injected controls. Ovulation responses were determined on the basis of initial blood progesterone concentrations being <1 ng/ml and achieving >5 ng / ml 10 d after the PG600 injection. The incidence of ovulating gilts having progesterone concentrations >30 ng/ml were recorded. During the study period, 10% of control gilts ovulated whereas 85–100% of hormone‐treated gilts ovulated. There were no significant differences among hormone groups for proportions of gilts ovulating. The proportions of gilts having circulating progesterone concentrations >30 ng/ml were increased (p ≤ 0.02) in all hCG treated groups compared with the PG600 group. In experiment 2, a total of 76 Hypor gilts at either 150 or 200 days of age were injected with PG600 (n = 18), 400 IU eCG followed by 200 IU hCG 24 h later (n = 20), PG600 followed by 100 IU hCG 24 h later (n = 17), or 400 IU eCG followed by 300 IU hCG 24 h later (n = 21). Blood samples were obtained 10 days later for progesterone assay. There were no effects of treatment or age on incidence of ovulation, but fewer 150‐day‐old gilts treated with PG600 or 400 IU eCG followed by 200 IU hCG had progesterone concentrations >30 ng / ml. We conclude that hCG treatment subsequent to PG600 treatment will generate a higher circulating progesterone concentration, although the effect is not evident in older, presumably peripubertal, gilts. The mechanism involved and implications for fertility remain to be determined.