DESCRIÇÃO DE TRÊS CASOS DE CRIPTORQUIDISMO EM EQUINOS DE RAÇA QUARTO DE MILHA EM PORTUGAL

O criptorquidismo consiste na não-descida dos testículos para o escroto, podendo ser uni ou bilateral. Cerca de 10% dos casos são de criptorquidismo bilateral e as situações unilaterais ocorrem frequentemente do lado esquerdo. Os testículos podem localizar-se na cavidade abdominal, no canal inguinal ou no tecido subcutâneo junto ao anel inguinal externo. As características das lesões macro e microscópicas do(s) testículo(s) dependem da idade do cavalo e da localização do testículo. Normalmente a observação macroscópica revela atrofia pronunciada e aumento da consistência. No exame histopatológico observa-se hipoplasia das células da linha germinativa e, em cavalos idosos, fibrose ao nível das túnicas. Os cavalos com criptorquidismo bilateral são estéreis mas, mantendo-se a produção de testosterona pelas células de Leydig, o comportamento sexual masculino não é alterado, apresentando-se, por vezes, estes animais mais agressivos que os não-criptorquídeos. Em equinos é considerado uma situação hereditária com carácter dominante, que ocorre com prevalência elevada em determinadas raças nomeadamente no American Quarter Horse (Quarto de Milha). Assim, mesmo os cavalos com criptorquidismo unilateral, que ainda apresentam de sémen, não devem ser utilizados para a reprodução devendo ser recomendada a sua castração. A castração pode ser efectuada por acesso inguinal, parainguinal, suprapúbico paramediano ou no flanco. Recentemente tem-se desenvolvido a castração por laparoscopia com o cavalo em estação ou em decúbito. O presente trabalho refere três casos de critptorquidismo esquerdo, em cavalos Quarto de Milha, castrados no Hospital Veterinário da Universidade de Évora (HVUE), com 2 1/2, 3 ½ e 6 anos de idade. Os testículos ectópicos localizavam-se, respectivamente, no anel inguinal, no tecido sub-cutâneo e na cavidade abdominal. A castração do cavalo cujo testículo se encontrava sub-cutâneo, junto ao anel inguinal externo, realizou-se por acesso inguinal, com o cavalo sedado e em estação. As outras duas cirurgias realizaram-se sob anestesia geral (por via inalatória) com os cavalos em decúbito dorsal sendo ambas iniciadas por acesso inguinal. O testículo de localização abdominal, teve que ser extraído por acesso parainguinal, dada a impossibilidade de exteriorização pelo anel inguinal. Ao exame macroscópico os testículos ectópicos encontravam-se atrofiados. O testículo com localização subcutânea apresentava forma irregular e os de localização no anel inguinal e na cavidade abdominal apresentavam, respectivamente, aumento da consistência e diminuição da mesma. Ao exame histopatológico observou-se, em todas as amostras, hipoplasia e degenerescência testicular severa sobretudo das células da linha germinativa, sendo que o testículo com localização abdominal apresentava ausência quase total destas células e também alterações degenerativas das células de Sertoli.#The cryptorchidism refers to the retention of one (unilateral) or both (bilateral) testicles and its absence in the scrotum. 10% of the cases of cryptorchidism are bilateral and the unilateral cases are frequently observed on the left side. The ectopic testicles can be located in the abdominal cavity, the inguinal ring or the sub-cutaneous tissue near the external inguinal ring. The macroscopic and microscopic lesions observed in the testicles depend both from the animal’s age as well as from the testicles’s location. More often the macroscopic examination reveals a marked atrophic testicle and a harder consistency of it. On the hystopathological exam we observe hypoplasia of the cells of the germinative pathway and in older horses a pronounced fibrosis in the area of the tunics. Horses with bilateral cryptorchidism suffer from sterility, however since the Leydig cells still produce testosterone, the mating behaviour and secondary sexual characteristics suffer no changes, horses are sometimes even more aggressive than non-cryptorchids horses. Cryptorchidism in horses is considered a hereditary situation with dominant character and has a high prevalence in some horse breeds like the American Quarter Horse. Concerning this fact, horses with this pathology, even if is unilateral and even with production of semen, should not be used as stallions and its castration should be recommended. The castration can be performed by several “traditional” approaches but presently some surgeons prefer the laparoscopic approach with the horse standing or in dorsal recumbency. The present work refers to three cases of left side cryptorchidism (unilateral) in American Quarter Horse that were castrated in the Hospital Veterinário da Universidade de Évora (HVUE). The three horses were 2 1/2, 3½ and 6 years old. The ectopic testicles were located in the inguinal ring (the 2 ½ years old horse), sub-cutaneous tissue (the 3½ years old horse) and in the abdominal cavity (the 6 years old horse). The surgery performed for the testicle located in the subcutaneous tissue was performed by inguinal approach with the animal standing and sedated. The other two surgeries were both performed with general inhalant anaesthesia with the animal in dorsal recumbency. Both surgeries were initially done by inguinal approach being the inguinal testicle well exteriorized by this approach. The intra abdominal testicle was impossible to remove through the inguinal ring so the para inguinal approach was used to exteriorize it. In the macroscopic examination all ectopic testicles were severely atrophic. The testicle removed from the subcutaneous tissue presented an irregular shape and the other testicles presented changes in consistency with higher consistency for the inguinal ring testicle and decreased consistency for the intra abdominal one. In the hystopathological examination, hypoplasia and severe testicular degenerative changes were observed in all samples especially in the germinative cells. In intra abdominal testicle these cells are almost absent and the Sertoli cells had marked degenerative changes

CP Violation in B and K Decays: 2003

These lectures give a brief description of CP violation in B and K meson decays with particular emphasize put on the determination of the CKM matrix. The following topics will be discussed: i) The CKM matrix, the unitarity triangle and general aspects of the theoretical framework, ii) Particle-antiparticle mixing and various types of CP violation, iii) Standard analysis of the unitarity triangle, iv) The ratio epsilon^prime/epsilon, v) The most important strategies for the determination of the angles $\alpha$, $\beta$ and $\gamma$ from B decays, vi) Rare decays $K^+\to\pi^+\nu\bar\nu$ and $K_L\to\pi^0\nu\bar\nu$ vii) Models with minimal flavour violation.Comment: Schladming lectures 2003, Main latex-file, 8 figures, 51 page

Neutrinoless double-beta decay with three or four neutrino mixing

Considering the scheme with mixing of three neutrinos and a mass hierarchy that can accommodate the results of solar and atmospheric neutrino experiments, it is shown that the results of solar neutrino experiments imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay, under the natural assumptions that massive neutrinos are Majorana particles and there are no unlikely fine-tuned cancellations among the contributions of the different neutrino masses. Considering the four-neutrino schemes that can accommodate also the results of the LSND experiment, it is shown that only one of them is compatible with the results of neutrinoless double-beta decay experiments and with the measurement of the abundances of primordial elements produced in Big-Bang Nucleosynthesis. It is shown that in this scheme, under the assumptions that massive neutrinos are Majorana particles and there are no cancellations among the contributions of the different neutrino masses, the results of the LSND experiment imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay.Comment: 18 pages including 2 figures, RevTe

The Problem of Large Leptonic Mixing

Unlike in the quark sector where simple $S_3$ permutation symmetries can generate the general features of quark masses and mixings, we find it impossible (under conditions of hierarchy for the charged leptons and without considering the see-saw mechanism or a more elaborate extension of the SM) to guarantee large leptonic mixing angles with any general symmetry or transformation of only known particles. If such symmetries exist, they must be realized in more extended scenarios.Comment: RevTeX, 4 pages, no figure

Spontaneous CP Violating Phase as The CKM Matrix Phase

We propose that the CP violating phase in the CKM mixing matrix is identical to the CP phases responsible for the spontaneous CP violation in the Higgs potential. A specific multi-Higgs model with Peccei-Quinn (PQ) symmetry is constructed to realize this idea. The CP violating phase does not vanish when all Higgs masses become large. There are flavor changing neutral current (FCNC) interactions mediated by neutral Higgs bosons at the tree level. However, unlike general multi-Higgs models, the FCNC Yukawa couplings are fixed in terms of the quark masses and CKM mixing angles. Implications for meson-anti-meson mixing, including recent data on $D-\bar D$ mixing, and neutron electric dipole moment (EDM) are studied. We find that the neutral Higgs boson masses can be at the order of one hundred GeV. The neutron EDM can be close to the present experimental upper bound.Comment: 16 pages, RevTex. Several typos corrected, and one reference adde

The Interplay Between the "Low" and "High" Energy CP-Violation in Leptogenesis

We analyse within the "flavoured" leptogenesis scenario of baryon asymmetry generation, the interplay of the "low energy" CP-violation, originating from the PMNS neutrino mixing matrix $U$, and the "high energy" CP-violation which can be present in the matrix of neutrino Yukawa couplings, $\lambda$, and can manifest itself only in "high" energy scale processes. The type I see-saw model with three heavy right-handed Majorana neutrinos having hierarchical spectrum is considered. The "orthogonal" parametrisation of the matrix of neutrino Yukawa couplings, which involves a complex orthogonal matrix $R$, is employed. In this approach the matrix $R$ is the source of "high energy" CP-violation. Results for normal hierarchical (NH) and inverted hierarchical (IH) light neutrino mass spectrum are derived in the case of decoupling of the heaviest RH Majorana neutrino. It is shown that taking into account the contribution to $Y_B$ due to the CP-violating phases in the neutrino mixing matrix $U$ can change drastically the predictions for $Y_B$, obtained assuming only "high energy" CP-violation from the $R$-matrix is operative in leptogenesis. In the case of IH spectrum, in particular, there exist significant regions in the corresponding parameter space where the purely "high energy" contribution in $Y_B$ plays a subdominant role in the production of baryon asymmetry compatible with the observations.Comment: Results unchanged; comments and references added; version to be puplished in Eur.Phys.J.

Neutrino masses from beta decays after KamLAND and WMAP (Updated including the NC enhanced SNO data)

The first data released by the KamLAND collaboration have confirmed the strong evidence in favour of the LMA solution of the solar neutrino problem. Taking into account the ranges for the oscillation parameters allowed by the global analysis of the solar, CHOOZ and KamLAND data, we update the limits on the neutrinoless double beta decay effective neutrino mass parameter and analyze the impact of all the available data from neutrinoless double beta decay experiments on the neutrino mass bounds, in view of the latest WMAP results. For the normal neutrino mass spectrum the range (0.05-0.23) eV is obtained for the lightest neutrino mass if one takes into account the Heidelberg-Moscow evidence for neutrinoless double beta decay and the cosmological bound. It is also shown that under the same conditions the mass of the lightest neutrino may not be bounded from below if the spectrum is of the inverted type. Finnaly, we discuss how future experiments can improve the present bounds on the lightest neutrino mass set by the Troitsk, Mainz and WMAP results. In the addendum we update the allowed ranges for the effective Majorana neutrino mass parameter in view of the latest NC enhanced SNO data.Comment: Updated including the recent NC enhanced SNO data. Refferences added and typos correcte

Leptogenesis in the type III seesaw mechanism

It is shown that the type III seesaw mechanism proposed recently can have certain advantages over the conventional (or type I) seesaw mechanism for leptogenesis. In particular a resonant enhancement of leptogenesis via heavy quasi-Dirac right-handed neutrino pairs can occur without a special flavor form or "texture" of the mass matrices being assumed. Some of the requirements for neutrino mixing and leptogenesis are effectively decoupled.Comment: 12 pages including one figure, several references adde

Spontaneous CP Violation in Non-Minimal Supersymmetric Models

We study the possibilities of spontaneous CP violation in the Next-to-Minimal Supersymmetric Standard Model with an extra singlet tadpole term in the scalar potential. We calculate the Higgs boson masses and couplings with radiative corrections including dominant two loop terms. We show that it is possible to satisfy the LEP constraints on the Higgs boson spectrum with non-trivial spontaneous CP violating phases. We also show that these phases could account for the observed value of epsilonK.Comment: 21 pages, 7 Figures in Encapsulated Postscrip

Vanishing Effective Mass of the Neutrinoless Double Beta Decay?

We stress that massive neutrinos may be Majorana particles even if the effective mass of the neutrinoless double beta decay m_ee vanishes. We show that current neutrino oscillation data do allow m_ee = 0 to hold, if the Majorana CP-violating phases lie in two specific regions. Strong constraints on three neutrino masses can then be obtained. We find that the neutrino mass spectrum performs a normal hierarchy: m_1 < m_2 < m_3. A possible texture of the neutrino mass matrix is also illustrated under the m_ee = 0 condition.Comment: RevTex 9 pages (2 PS figures included). More discussions and references added. Results partly changed. To appear in Phys. Rev.