Efferent connections of the prefrontal cortex of echidna (Tachyglossus aculeatus)

In two echidnas injections of radioactively labeled amino acids were made into the cortical area which has been shown to receive afferents from the anteromediodorsal region of the thalamus and which is therefore tentatively identified as the prefrontal cortex. Efferents were found in the symmetrical area of the contralateral cortex, in the paleocortex and neostriatum bilaterally, the ipsilateral anteromediodorsal region of the thalamus, the hypothalamus, the ventral tegmental area, and the pons. No evidence was found of efferents caudal to the pons. The axons reached the contralateral side via the anterior commissure. The innervation of the cortex was columnar and that of the neostriatum patchy, as was previously demonstrated for comparable projections in placental mammals. The present material, albeit limited, shows some remarkable similarities between prefrontal efferents in the echidna and the placental mammals, including Old World monkeys.     

Hyperthermic perfusion of the distended urinary bladder in the management of recurrent transitional cell carcinoma.

The clinical and histological changes following hyperthermic perfusion of the distended urinary bladder have been studied in 13 patients with transitional cell carcinoma, persistent after radical radiotherapy. Continuous epidural anaesthesia was necessary to achieve a constant state of bladder relaxation during irrigation of the distended bladder. This form of hyperthermic perfusion of the bladder was effective in arresting uncontrollable haemorrhage from bladder tumours and may be of value in the treatment of this complication. Perfusion at an outflow temperature of 44 degrees C for 4 hours caused tumour necrosis. It was, however, associated with damage to the vasculature of the bladder and frequency of micturition which persisted after mucosal recovery. Perfusion at 43 degrees C also caused tumour necrosis and the after effects were less severe.     

The Allografted Parathyroid Gland: Evaluation of Function in the Immunosuppressed Host

Parathyroid autografts were performed in 19 random bred mongrels and parathyroid allografts were exchanged between seven random bred mongrels. Three pairs of siblings from a beagle colony were immunosuppressed and parathyroid allografts exchanged between them. The parathyroid autografts were successful, while parathyroid allografts failed on all occasions in the non-immunosuppressed host. In immunosuppressed animals, however, the allografts were successful in five of six dogs. The success of parathyroid transplantation was determined by the following observations: 1) The experimental animal, having grafted parathyroid tissue as the only source of hormone, maintained a normal or near normal serum calcium concentration. 2) Following removal of the parathyroid graft, there was an immediate fall in the serum calcium concentration associated with tetany and/or death. 3) Histological study of the grafted gland revealed normal architecture, and 4) Radioimmunoassay of extracted grafts revealed moderate to large quantities of parathyroid hormone.     

Brainstem auditory evoked responses in infants at risk of sudden infant death

Brainstem auditory evoked responses (BAERs) were recorded from 63 near-miss Sudden Infant Death Syndrome (NMSIDS) infants, 26 siblings of SIDS (SSIBS) infants and 67 control infants between 0 and 30 weeks post-term. The majority of BAERs recorded from the NMSIDS and SSIBS infants had normal form and interpeak intervals (V-I and V-IIn) within normal limits for their age. However, 15% of these infants had interpeak intervals outside the normal range, suggesting abnormal neural function in these cases. The distributions of interpeak intervals for all NMSIDS and SSIBS infants were skewed towards longer times compared to control infants. The distributions of V-IIn intervals for both groups of at risk infants were significantly different to that of control infants. While the observations confirm that the recording of BAERs is not suitable for identifying infants at risk of SIDS, they suggest, however, that maturation of neural processing in the brainstem of these infants may be delayed.     

Local cerebral glucose utilization in controlled graded levels of hyperglycemia in the conscious rat

Local cerebral glucose utilization assayed by the [14C]deoxyglucose ([14C]DG) method and calculated by means of its operational equation with values for the rate constants and lumped constant determined in rats under physiological conditions remains relatively stable with variations in arterial plasma glucose concentration within the normoglycemic range. Large changes in arterial plasma glucose level may, however, significantly alter the values of these constants and lead to artifactual results. Values for the lumped constant have been measured and reported for a wide range of arterial plasma glucose concentrations ranging from hypoglycemia to hyperglycemia in the rat (Schuier et al., 1981; Suda et al., 1981; Pettigrew et al., 1983). In the present study we have redetermined the rate constants in rats with arterial plasma glucose levels clamped at approximately 350, 450, and 550 mg/dl (i.e., 19, 25, and 31 mM) by a glucose clamp technique. The rate constants for the transport of DG from plasma to brain, K1*, and its phosphorylation in tissue, k3*, were found to decline with increasing plasma glucose levels, while the rate constant for its transport back from brain to plasma, k*2, remained relatively unchanged from its value in normoglycemia. These rate constants were used together with the previously determined values for the lumped constants to calculate local rates of cerebral glucose utilization in three groups of rats in which arterial plasma glucose levels were clamped at approximately 350, 450, and 550 mg/dl (i.e., 19, 25, and 31 mM). Average glucose utilization in the brain as a whole was unchanged in hyperglycemia from the values calculated in normoglycemic rats with the standard normal set of constants. Changes in the rate of glucose utilization were found, however, in the hypothalamus, globus pallidus, and amygdala during hyperglycemia.