RESUMO
Llama production in Argentina has increased, as the international interest in breeding this type of animals has grown in the last years. Considering the great polymorphism that llama spermatozoa present at evaluation using light microscopy, the aim of this study was to objectively evaluate llama sperm head morphometry using digital morphometric analysis. Five ejaculates from each of eight males were obtained to evaluate morphometric parameters of 8000 sperm heads stained with Tinción 15(®). The following average results were obtained for each parameter: size parameters: area 20.09 µm(2), length 6.60 µm, width 4.14 µm, equivalent circle diameter 5.06 µm, curve length 5.79 µm and curve width 3.48 µm; boundary parameters: perimeter 18.54 µm and convex perimeter 17.34 µm; and shape parameters: roundness 1.28 and elongation 1.59. Morphometric parameters of sperm head were compared between ejaculates of the same male and between males. Significant differences between ejaculates of the same male were found for all parameters evaluated (P < 0.01). Significant differences between males were found for all morphometric parameters (P < 0.01) except for curve length, curve width and perimeter. The differences detected would indicate that there is not a single morphometric pattern for Lama glama sperm head, because parameter values cannot be standardised.
Assuntos
Camelídeos Americanos , Cabeça do Espermatozoide/ultraestrutura , Animais , MasculinoRESUMO
Llama semen is highly viscous. This characteristic is usually evaluated subjectively by measuring the thread formed when carefully pippeting a sample of semen. The aims of this study were (i) to objectively determine and analyse llama semen viscosity, (ii) to compare semen viscosity between ejaculates of the same male as well as between different males, (iii) to study the correlation between viscosity and other semen characteristics and (iv) to evaluate the effect of collagenase on semen viscosity. Semen viscosity was evaluated using a cone-plate Brookfield rotational viscometer. A non Newtonian, pseudoplastic behaviour was observed in the 45 semen samples evaluated. Rheological parameters were determined obtaining the following results (mean ± SD): apparent viscosity at 11.5 s(-1): 46.71 ± 26.8 cpoise and at 115 s(-1): 12.61 ± 4.1 cpoise; structural viscosity (K) (dyne s cm(-2)): 2.18 ± 1.4 and coefficient of consistency (n): 0.45 ± 0.1. Statistical differences were found between different ejaculates of the same male for structural viscosity and apparent viscosity at 11.5 s(-1) (P < 0.01). Correlation was found only between coefficient of consistency (n) and sperm concentration (P < 0.01). Significant differences for coefficient of consistency (n) and viscosity at 115 s(-1) were found between samples incubated with and without collagenase (P < 0.05).
Assuntos
Sêmen , Viscosidade , Animais , Camelídeos Americanos , MasculinoRESUMO
The effect cryopreservation has on sperm chromatin condensation has been studied in many species but not in South American camelids. The objectives of this study were to evaluate with toluidine blue (TB) the effects of cooling and of adding collagenase on llama sperm DNA condensation. The optimum incubation time (30 s, 1.5 and 3 min) with a reducing agent (dithiothreitol) was also determined. When comparing cooled samples with the raw ejaculate, a significant increase in sperm showing a high degree of decondensation (TB positive) was observed (P = 0.005). A positive correlation was observed, both in raw and cooled semen, between sperm head morphological abnormalities observed in TB-stained cells and TB-positive sperm (highly decondensed DNA), but not with TB-intermediate spermatozoa (moderately decondensed DNA). No significant differences (P > 0.05) were observed in samples incubated with or without 0.1% collagenase. In cooled semen, but not in raw, a significant increase (P = 0.000) in reacted sperm (TB positive) was observed using 3-min incubation with 1% dithiothreitol (DTT). To conclude, cooling would seem to produce an increase in llama sperm chromatin decondensation. Also, 0.1% collagenase in H-TALP-BSA could be added to raw semen to aid its manipulation as it would not seem to increase DNA decondensation.
Assuntos
Colagenases/administração & dosagem , Criopreservação , DNA/química , Preservação do Sêmen , Espermatozoides/ultraestrutura , Cloreto de Tolônio/química , Animais , Camelídeos Americanos , Cromatina/metabolismo , Masculino , Espermatozoides/metabolismoRESUMO
Pasteur had annoying opponents at the Medical Academy of Paris, probably because he was not a physician. The medical aspect of his creation reached highest altitude when he vaccinated the boy José Meister against rabies. By that time, he was crippled by a hemiplegia suffered when he was 46 years old. Studying tartric acid isomer, Pasteur discovered molecular asymmetry. He hypothesized that life operated asymmetrically, when he discovered the selectivity of Penicillium glaucum fungus action on paratartrates. He discovered anaerobic life and discarded the theory of spontaneous generation. At the age of 70, he received the gratitude of France and the whole mankind, through President Carnot. On that occasion he said to youngsters "Live in the calm peace of laboratories and libraries. Ask yourselves: What have I done for my instruction?, What have I done for my country?, until the moment that you reach the immense happiness of thinking that you have contributed to mankind's progress and welfare."
Assuntos
Microbiologia/história , Aniversários e Eventos Especiais , História do Século XIXRESUMO
The Chilean President José Manuel Balmaceda (1886-1891) had a constitutional conflict with the parliament. This conflict lead to a revolution that ended with the President's suicide, when he was refuged at the Argentinian Embassy in September 1891. President Balmaceda conducted an authoritarian government during several months. A decree from February, 1897, disposed the reorganization of the Medical School, dismissed and imprisoned the Dean, Dr Barros-Borgoño and nominated new Professors. Dr Nicanor Rojas, Professor of Gynecology was assigned as Dean and Dr Carlos Sazié as secretary. During the During the war against Perú and Bolivia, Dr. Rojas worked gratuitously and became prominent, being named Chief Surgeon of the Chilean Army. After the triumph of the revolution against President Balmaceda, Dr Rojas was discharged, and died in 1892.
Assuntos
Faculdades de Medicina/história , Pessoal Administrativo/história , Chile , História do Século XIXRESUMO
The conflict between the Chilean President Balmaceda and the parliament lead him to rule the country despotically during 8 months, until his suicide in 1891. During this lapse he persecuted and imprisoned his opponents, including several Medical School professors. Doctor David Benavente, professor of Anatomy and Balmaceda's opponent, wrote a chronicle at the Revista Médica de Chile (1897; 20:46) referring to the changes that occurred at the Medical School: "Flogged by dictatorship's winds, it barely gave sings of life during the eight months that Balmaceda dominated the country". Political passion almost annihilated for ever the first scientific teaching center of the University of Chile, posed a project at the Public Instruction Council "to create in all high schools a special class about the general principles of the Constitution". Once democratic normality was re-established, the development of Chilean Medicine was greatly impelled, sending young physicians to specialize at qualified european centers.
Assuntos
Medicina Clínica/história , Chile , História do Século XIX , Sistemas Políticos/históriaRESUMO
José Manuel Balmaceda was president of Chile between 1886 and 1891. Confronted with an institutional conflict, he was deposed by the Republic's parliament in January, 1891. Some distinguished physicians were members of that parliament; Dr Alfonso Valderrama, senator, chronicler of Revista Médica de Chile's first issues and General Secretary of the University of Chile; Dr José Joaquín Aguirre, deputy. Dean of the Faculty of Medicine (1817-1889) and Rector of the University of Chile; Dr Federico Puga Borne, deputy and Minister of Public Instruction and Justice; Dr Augusto Orrego Luco, deputy and writer; Dr José Arce, deputy. President Balmaceda decreed the intervention of the Medical School in February 1891, named Dr Arce as intervenor and designed professors attached to his government. He also dismissed several physicians. Overwhelmed by the political conflict, Balmaceda took refuge in the Argentinian embasy and committed suicide in September, 1891.
Assuntos
Medicina Clínica , Chile , História do Século XIX , GuerraRESUMO
The first medical strife in Chile occurred in the city of Valparaiso. The intendant protested to the examining board of physicians because 5 doctors refused to give emergency medical care to a patient late at night. "Is fair that both the authority and the public have the right to demand those services and it is not natural that their fulfillment depend on the good or bad will of the physicians". The intendant proclaimed a decree establishing a weekly obligatory nocturnal medical services of two physicians under police control and fine threaten. The 14 doctors of the city menaced to resing to their profession considering that the decree "violates constitution and laws." The medical corps of Santiago made common cause with their colleagues "profoundly irritated". The conflict was finally resolved.