Studies on equine prematurity 3: Insulin secretion in the foal during the perinatal period

The factors influencing beta cell function in the foetal and neonatal foal have been investigated in chronically catheterised foetal foals and in newborn foals delivered either spontaneously at term or by induction at different gestational ages. Insulin was detected in the foetal plasma from as early as 150 days of gestation (term = 340 days) and during the last third of gestation the foetal beta cells responded to exogenous administration of glucose and arginine and to endogenous variations in the glucose level. Insulin secretion by the foetal beta cells was depressed by anaesthesia and surgery. At birth, there was a significant positive correlation between the plasma concentrations of insulin and glucose irrespective of the maturity at birth or type of delivery (r = 0.86, n = 39, P less than 0.01). The slope of this relationship was significantly less than that relating the postoperative foetal concentration but only when delivery was difficult or prolonged was the beta cell sensitivity to glucose completely abolished. At birth, there were no significant differences in the plasma concentrations of insulin or glucose between full term foals delivered spontaneously or by induction. However, the spontaneously delivered foals showed a transient increase in the insulin concentration 15 mins after birth which was not observed in the full term foals delivered by induction. Plasma glucose concentrations were maintained during the 2 h after birth in the absence of sucking in both the induced and the spontaneously delivered full term foals. Premature foals had significantly lower plasma glucose concentrations at birth than full term foals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coupling of south american and african plate motion and plate deformation

Although the African Plate's northeastward absolute motion slowed abruptly 30 million years ago, the South Atlantic's spreading velocity has remained roughly constant over the past 80 million years, thus requiring a simultaneous westward acceleration of the South American Plate. This plate velocity correlation occurs because the two plates are coupled to general mantle circulation. The deceleration of the African Plate, due to its collision with the Eurasian Plate, diverts mantle flow westward, increasing the net basal driving torque and westward velocity of the South American Plate. One result of South America's higher plate velocity is the increased cordilleran activity along its western edge, beginning at about 30 million years ago.     

Overview and initial results of the very long baseline interferometry space observatory programme

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.     

Effect of Short-Term Restricted Food Intake on Canine Pseudopregnancy

A non-pharmaceutical, dietary option may be useful to manage clinical pseudopregnancy (PSP). To describe the effect of short-term food restriction on canine PSP, 16 privately owned, overtly pseudopregnant bitches were randomly assigned to one of the following groups: Limit-fed (increasing amounts of a restricted maintenance: 50%, 40%, 30% restriction for 2, 3 and 2 days respectively) during 7 days (n = 8) or Maintenance-fed of the same food and period (n = 8). The bitches were physically examined and blood samples were taken for prolactin and progesterone determinations on days 2, 5 and 8. By day 8, none of the bitches had completely regressed the condition although all (8/8) the animals of the Limit-fed and two (25%) of the Maintenance-fed group improved in condition decreasing mammary size and secretion (p < 0.05). No day or group effects were observed for serum prolactin and progesterone concentrations (>0.05). It is concluded that although an 8-day food restriction did not cure PSP, it seemed to hasten PSP signs involution in these bitches. No endocrine change was related to these clinical findings.     

Surgical removal of a choroid plexus oncocytoma in an adult cat

An 11‐year‐old male castrated domestic shorthair cat presented with left central vestibular dysfunction. Magnetic resonance imaging of the brain revealed a large, extra‐parenchymal, strongly contrast‐enhancing mass at the level of the left cerebellopontine angle and compressing the cerebellum and brainstem. The mass was surgically excised via left rostral and sub‐tentorial craniectomies and histopathology revealed an epithelial neoplasm composed of anastomosing cords of neoplastic cells that contained large amounts of finely granular hypereosinophilic cytoplasm and round nuclei. The cytoplasmic granules were variably positive with periodic acid‐Schiff and modified Gomori trichrome. Immunohistochemical staining with anti‐cytokeratin AE1/AE3 was diffusely positive. Electron microscopy revealed neoplastic cells that were full of electron‐dense organelles consistent with mitochondria. This is the first case of a choroid plexus oncocytoma in the central nervous system of any domestic animal species and highlights the role of successful surgical intervention in extra‐parenchymal neoplasia in the central nervous system.     

Evaluation of the oral antimitotic agent (ABT-751) in dogs with lymphoma

Background

ABT‐751 is a novel orally available antimitotic agent that targets microtubule polymerization. This mechanism may suggest potential activity in canine lymphoma.

Objective

Determine a maximum tolerated dose for ABT‐751, and assess long‐term tolerability and activity in canine lymphoma.

Animals

Thirty dogs with newly diagnosed (n = 19) or relapsed (n = 11) non‐Hodgkin's lymphoma.

Methods

Dogs (n = 11) were enrolled in a rapid dose escalation study to define the maximum tolerated dose. Upon definition of a maximally tolerated dose, a cohort expansion of 19 dogs allowed verification of long‐term tolerability and assessment of activity. Study endpoints in the cohort expansion included chronic tolerability, response rate, response duration, and time to progression. Additional endpoints included serum pharmacokinetics, lymph node drug concentrations, and changes in circulating endothelial cells.

Results

The maximum tolerated dose of ABT‐751 was 350 mg/m² PO q24h. Dose‐limiting toxicities included vomiting and diarrhea, which resolved with a schedule adjustment to 350 mg/m² PO q48h. ABT‐751 was consistently detected in lymphoma tissue samples from dogs treated at or above the maximum tolerated dose. In the cohort expansion, objective responses were seen in 3/15 (20%) dogs with a response duration ranging from 21 to 111 days. Decreases in circulating endothelial cells were seen in 10 dogs at day 7 (2 responding dogs and 8 nonresponding dogs).

Conclusion

ABT‐751 was well tolerated at 350   mg/m² PO q24h for 7 days and then q48h thereafter. Activity of ABT‐751 suggested a rationale for additional studies of ABT‐751 as part of a combination chemotherapy protocol for lymphoma or other canine cancers.