Equine pituitary pars intermedia dysfunction: current understanding and recommendations from the Australian and New Zealand Equine Endocrine Group

The purpose of this article is to provide a review of the current knowledge and opinions about the epidemiology, clinical findings (including sequelae), diagnosis, treatment and monitoring of equine pituitary pars intermedia dysfunction, particularly in the Australian context. This information and the recommendations provided will assist practitioners in making informed decisions regarding the diagnosis and management of this disorder.     

A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

Long-term survival after combination chemotherapy for bilateral renal malignant lymphoma in a dog

CASE HISTORY: A 6-year-old, entire male Flat-coated Retriever was presented with a history of lethargy, polydipsia and seizures. Clinical chemistry had shown marked azotaemia.

CLINICAL FINDINGS AND DIAGNOSIS: Radiography and ultrasonography revealed bilateral renomegaly, and cytology of fine needle aspirates from the kidneys was diagnostic of malignant lymphoma. The dog was treated with a modified high-dose cyclophosphamide-, vincristine-, and prednisolone-based chemotherapy protocol, achieved remission, and returned to normal quality of life. Survival time was 346 days from the time of diagnosis.

CLINICAL RELEVANCE: Malignant lymphoma in the kidneys of dogs has been considered to carry a uniformly poor prognosis. Long-term remission after medical treatment has not previously been reported. The favourable outcome in this case illustrates the limitations of clinical staging in determining the outcome for individual patients.     

Short‐Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea Pigs

In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ‐cell morphology remain unclear. This study evaluates the short‐term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30‐day old) and adult (65‐ and 135‐day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non‐steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post‐pubertal and adult guinea pigs, in addition to causing germ‐cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis.     

Transform-limited, narrow-linewidth lasing action in organic semiconductor microcavities

Lasing action in organic vertical-cavity surface-emitting laser (OVCSEL) structures is demonstrated. Optically pumped OVCSELs with an active layer composed of a thin-film organic semiconductor tris-(8-hydroxyquinoline) aluminum (Alq3) doped with DCM laser dye produced very narrow linewidth (0.2 +/- 0.1 angstrom), high-power (3 watts) emission that could be varied in different devices from orange to red. The efficient energy transfer from Alq3 to DCM results in a threshold input energy of 300 microjoules per square centimeter. An operational lifetime >10(6) laser pulses was achieved for a device operated well above threshold in atmosphere. The linewidths above threshold are Fourier transform-limited and could potentially be narrowed further.