D. B. Church

Primary hypoparathyroidism in two horses

Two Thoroughbred horses were presented with various clinical signs which included sweating, agitation, muscle twitching and synchronous diaphragmatic flutter. These signs were associated with profound hypocalcaemia. A diagnosis of primary hypoparathyroidism was made on the basis of low serum ionised calcium concentration, hyperphosphataemia and markedly reduced serum immunoreactive parathyroid hormone concentrations in the presence of normal renal function. Treatment with a combination of intravenous calcium and subsequently oral calcium, magnesium and a vitamin D analogue (dihydrotachysterol) for up to 65 days resulted in complete remission of clinical signs. Horse 1 was euthanased 12 months after the initial recognition of signs. Results of necropsy were unremarkable apart from an absence of detectable parathyroid tissue. Horse 2 returned to athletic activities while receiving only maintenance doses of oral calcium carbonate.

Morphometric study of the beta-cell volume of the canine pancreas with consideration of the axis of tissue transection

The pancreatic β‐cell volume was assessed in 12 clinically normal crossbred dogs using immunohistochemical labelling for insulin and computer‐assisted morphometric analysis. The β‐cell volume was less in the right lobe compared with the body and left lobe, but the β‐cell volume did not differ between the body and the left lobe as reported previously. The use of immunohistochemistry, computer‐assisted morphometry, the inclusion here of extra‐islet β‐cells and the exclusion of non‐β‐endocrine cells in the investigation of the β‐cell volume may have contributed to this discrepancy. As most β‐cells form irregularly shaped three‐dimensional bodies (islets of Langerhans), the effect of the plane of tissue transection (sagittal, transverse, oblique) on the calculation of the β‐cell volume was also examined. The β‐cell volume in the sagittal plane of the right lobe was lower than the volume in the oblique plane of the same lobe but was not different from the volume in the transverse plane. However, there were no differences in β‐cell volume in different planes in the body or left lobe. When quantifying β‐cell volume in health or disease, variation in the volume of β‐cells in different locations of the pancreas is an important consideration and the plane of transection may also influence results.