Comparison of Mathematical Models Applied to F1 Dairy Sheep Lactations in Organic Farm and Environmental Factors Affecting Lactation Curve Parameter

The objective of this study was to compare the goodness of fit of four lactation curve models: Wood’s Gamma model (WD), Wilmink (WL), and Pollott’s multiplicative two (POL2) and three parameters (POL3) and to determine the environmental factors affecting the complete lactation curve of F1 dairy sheep under organic management. A total of 5,382 weekly milk yields records from 150 ewes, under organic management were used. Residual mean square (RMS), determination coefficients (R2), and correlation (r) analysis were used as an indicator of goodness of fit for each model. WL model best fitted the lactation curves as indicated by the lower RMS values (0.019), followed by WD (0.023), POL2 (0.025) and POL3 (0.029). The four models provided total milk yield (TMY) estimations that were highly correlated (0.93 to 0.97) with observed TMY (89.9 kg). The four models under estimated peak yield (PY), whereas POL2 and POL3 gave nearer peak time lactation estimations. Ewes lambing in autumn had higher TMY and showed a typical curve shape. Higher TMY were recorded in second and third lambing. Season of lambing, number of lambing and type of lambing had a great influenced over TMY shaping the complete lactation curve of F1 dairy sheep. In general terms WL model showed the best fit to the F1 dairy sheep lactation curve under organic management

Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with chitosan bioma terial preloaded with progesterone [Regeneraci�n del nervio ci�tico axotomizado del perro mediante la t�cnica de tubulizaci�n con el biomaterial quitosana precargado con progesterona]

Introduction. Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. Aims. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised-tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. Materials and methods. Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. Results. The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non-myelinated fibres were observed in all cases. Conclusions. The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve

Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with chitosan bioma terial preloaded with progesterone [Regeneración del nervio ciático axotomizado del perro mediante la técnica de tubulización con el biomaterial quitosana precargado con progesterona]

Introduction. Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. Aims. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised-tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. Materials and methods. Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. Results. The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non-myelinated fibres were observed in all cases. Conclusions. The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve

[Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with Chitosan biomaterial preloaded with progesterone]

INTRODUCTION: Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. AIMS. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. MATERIALS AND METHODS: Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. RESULTS: The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non myelinated fibres were observed in all cases. CONCLUSIONS: The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve

Regeneration of the dog's axotomized sciatic nerve with pregnenolone-saturated chitosan prosthesis implanted through the tubulization technique [Regeneración del nervio ciático axotomizado del perro con prótesis de quitosana precargadas con pregnenolona y la técnica de tubulización]

Peripheral nerves can be injured by traumatisms or mechanical causes, and thermal, ischemic or tumoral damage, this could present inconveniences of the mobility, sensibility and loss of motor function at the denervated area. The surgical techniques applied to repair nerves have gone through several phases of evolution such as the tubulization technique which consists of a prosthesis with a pipe shape at the segment injured. In this work the biomaterial utilized to manufacture the prosthesis was chitosan, since this compound allows to incorporate to its matrix promoting nervous growing substances that are released in situ for a long time while being degraded by titular lysosomes of organic origin. It is known, by diverse studies, that several neurosteroids are involved during the regeneration process of peripheral nerves, which functions are already described, as pregnenolone. In order to determine if there was or not regeneration and the degree of maturity of this,12 young French Poodle female dogs of 1 to 1.5 years old were used (four were used as intact control group, four were subjected to tubulization technique with chitosan, and four went into tubulization technique with chitosan and pregnenolone neurosteroid, which is a stem hormone), in order to correct 15 mm of axotomized segment. The regenerated nerves were evaluated by means of electronic microscopy of transmission and light, performing cross cuts of 60-70 nm and 1 μm in thickness for their histological analysis. The morphological findings showed a similar structure to that of an intact nerve, since the number of myelinated axons, not myelinated and the proportion "g" (which indicates the ripening degree of the axon), were similar, indicating that the regeneration of the axotomized nerves and tubulization was achieved, independently of the administered treatment

Regeneration of the dog's axotomized sciatic nerve with pregnenolone-saturated chitosan prosthesis implanted through the tubulization technique [Regeneraci�n del nervio ci�tico axotomizado del perro con pr�tesis de quitosana precargadas con pregnenolona y la t�cnica de tubulizaci�n]

Peripheral nerves can be injured by traumatisms or mechanical causes, and thermal, ischemic or tumoral damage, this could present inconveniences of the mobility, sensibility and loss of motor function at the denervated area. The surgical techniques applied to repair nerves have gone through several phases of evolution such as the tubulization technique which consists of a prosthesis with a pipe shape at the segment injured. In this work the biomaterial utilized to manufacture the prosthesis was chitosan, since this compound allows to incorporate to its matrix promoting nervous growing substances that are released in situ for a long time while being degraded by titular lysosomes of organic origin. It is known, by diverse studies, that several neurosteroids are involved during the regeneration process of peripheral nerves, which functions are already described, as pregnenolone. In order to determine if there was or not regeneration and the degree of maturity of this,12 young French Poodle female dogs of 1 to 1.5 years old were used (four were used as intact control group, four were subjected to tubulization technique with chitosan, and four went into tubulization technique with chitosan and pregnenolone neurosteroid, which is a stem hormone), in order to correct 15 mm of axotomized segment. The regenerated nerves were evaluated by means of electronic microscopy of transmission and light, performing cross cuts of 60-70 nm and 1 ?m in thickness for their histological analysis. The morphological findings showed a similar structure to that of an intact nerve, since the number of myelinated axons, not myelinated and the proportion "g" (which indicates the ripening degree of the axon), were similar, indicating that the regeneration of the axotomized nerves and tubulization was achieved, independently of the administered treatment

Immunological study of a chitosan prosthesis in the sciatic nerve regeneration of the axotomized dog

This study demonstrated that when the regeneration of the axotomized sciatic nerve is induced through tubulization with chitosan, this biomaterial does not induce immunostimulation or immunodepression in the dog. Canine females were distributed among three groups: an intact control group which was only isolated, an axotomized control group, and an axotomized group which was tubulized with 3% chitosan prostheses. In vitro culture and phagocytosis tests, as well as IgG and IgM serum concentrations, were determined in peripheral blood on days 0, 15, 30 and 60. The results showed that chitosan implants did not importantly affect the immune response

The Impact of LEP G-2548A and LEPR Gln223Arg Polymorphisms on Adiposity, Leptin, and Leptin-Receptor Serum Levels in a Mexican Mestizo Population.

The polymorphisms in leptin (LEP G-2548A) and leptin-receptor (LEPR Gln223Arg) seem to influence obesity and lipid metabolism among others. The aim of this study was to investigate the effect of these polymorphisms on adiposity, leptin (sLeptin), and leptin-receptor (sLeptin-receptor) serum concentrations as well as inflammation markers. We included 382 adults originally from Western Mexico. They were genotyped by PCR-RFLP. Obese individuals showed higher sLeptin (58.2 +/- 31.35ng/mL) but lower sLeptin-receptor (12.6 +/- 3.74ng/mL) levels than normal weight ones (17.6 +/- 14.62ng/mL, 17.4 +/- 4.62ng/mL, resp.), P < 0.001. Obese subjects carriers of Arg/Arg genotype had more (P = 0.016) sLeptin-receptor (14.7 +/- 4.96ng/mL) and less (P = 0.004) sLeptin (44.0 +/- 28.12ng/mL) levels than Gln/Gln genotype (11.0 +/- 2.92ng/mL, 80.3 +/- 33.24ng/mL, resp.). Body fat mass was lower (P from 0.003 to 0.045) for A/A (36.5% +/- 6.80) or Arg/Arg (36.8% +/- 6.82) genotypes with respect to G/G (41.3% +/- 5.52) and G/A (41.6% +/- 5.61) or Gln/Gln (43.7% +/- 4.74) and Gln/Arg (41.0% +/- 5.52) genotypes carriers. Our results suggest that LEP -2548A and LEPR 223Arg could be genetic markers of less body fat mass accumulation in obese subjects from Western Mexico