Metastatic osteosarcoma of the kidney presenting as renal hemorrhage.

PURPOSE: Renal osteosarcoma may arise as a metastasis from a primary bone osteosarcoma or as a primary renal tumor. Metastatic renal osteosarcoma has been found at autopsy in approximately 10% of patients who die of this disease. PATIENT AND METHODS: A case report of a young Chinese patient presenting with acute onset of renal infarction and hemorrhage from a renal metastasis of osteosarcoma is presented, as well as a review of the literature. RESULTS: Some patients with solitary renal metastatic osteosarcoma may have long-term disease-free survival after nephrectomy. Early diagnosis and thus increased awareness of this condition is important.

Suicide and aging. II: The psychobiological interface.

There is an accumulating body of research suggesting that suicidal behavior may be associated with abnormalities of the central serotonin system. Other monoaminergic, peptidergic, and neuroendocrine systems have been implicated as well. A review of studies that examine neurobiological variables in postmortem tissue of suicide victims and controls reveals that investigators in most instances have viewed age as a confound to be controlled rather than considering it as a variable of interest. However, the close associations between aging and increased suicide rates, and the knowledge that the functional integrity of many of these same systems changes with normal and abnormal aging processes, raise the possibility that biological aging contributes to suicide risk, and that the underlying neurobiology of suicide in the elderly differs from that of younger people. The few available studies that did examine the association of age with neurobiological measures indicate directions for future research into the role that aging may play in determining the biological bases of suicide risk.

Dorsomedial medulla stimulation activates rat supraoptic oxytocin and vasopressin neurones through different pathways.

1. This study utilized retrograde anatomical tracer techniques and in vivo extracellular electrophysiological studies to examine caudal ventrolateral and dorsomedial medulla afferents to supraoptic nucleus neurosecretory neurones in male Long-Evans rats. 2. In one series of experiments, pentobarbitone-anaesthetized animals were subjected to ventral exposure of the hypothalamus and rhodamine-tagged latex microspheres (0.05-0.2 microliter) were injected into one supraoptic nucleus. Following perfusion with paraformaldehyde-glutaraldehyde 18-24 h later, cell counts were obtained of rhodamine- and/or catecholamine-labelled neurones in the caudal ventrolateral and dorsomedial medulla both ipsi- and contralateral to the injection site. 3. In the caudal ventrolateral medulla, each injection labelled fewer than 15% of the catecholaminergic neurones; with small injections, most (68-100%) of the rhodamine-labelled neurones also displayed catecholamine histofluorescence. In the caudal nucleus tractus solitarii, one-half to one-third as many rhodamine-labelled cells were observed, but a higher percentage (13-100%) of these were non-catecholaminergic. 4. Extracellular recordings were obtained from antidromically identified supraoptic neurones classified as vasopressin (n = 106) or oxytocin (n = 26) secreting. Single cathodal pulses (0.2 ms duration, 0.02-0.08 mA) applied in the caudal half of the ipsilateral nucleus tractus solitarii evoked a transient (30-50 ms) activation of 63% of both vasopressin- and oxytocin-secreting neurones. Mean latencies (+/- S.E.M.) for vasopressin and oxytocin cells were 49.8 +/- 1.0 and 46.5 +/- 2.4 ms respectively; these were not significantly different. Similar responses were noted to contralateral stimuli applied to four vasopressin and two oxytocin cells. 5. Vasopressin neurones activated by caudal nucleus tractus solitarii stimulation displayed similar patterns of response to stimulation in the caudal ventrolateral medulla. However, latencies from the nucleus solitarius (mean 47.6 +/- 1.4 ms; n = 59) were significantly longer (P less than 0.05) than from the ventrolateral medulla (41.5 +/- 2.0 ms; n = 17). In eight out of eleven vasopressin neurones tested, interruption of synaptic transmission through the ventrolateral medulla reduced or abolished the caudal nucleus tractus solitarii-evoked excitation but had no effect on their response to baroreceptor activation. This manoeuvre affected zero out of five oxytocin cells similarly excited by nucleus solitarius stimulation. 6. These observations indicate that visceral input mediated through the nucleus tractus solitarii is transmitted differentially to supraoptic vasopressin- and oxytocin-secreting neurones.

Diagonal band projection towards the hypothalamic supraoptic nucleus: light and electron microscopic observations in the rat.

Supraoptic nucleus (SON) neurons receive a prominent gamma-amino-butyric acid (GABA) input. This study evaluated the hypothesis, partly on the basis of recent electrophysiological data, that this innervation might arise from GABAergic neurons located in the ventral diagonal band of Broca area. For retrograde transport studies, pentobarbital-anesthetized male Long-Evans rats received 0.03-0.20-microliter injections of a suspension of rhodamine tagged latex microspheres into the SON. In two cases where such injections were confined to the SON, less than 60 retrogradely labeled neurons were detected in the ipsilateral diagonal band. In three animals where injections extended into the perinuclear zone around the SON, more than 2,000 retrogradely labeled cells were counted in the ipsilateral diagonal band. For anterograde transport studies, another group of animals received either 30% horseradish peroxidase (HRP) in 0.5% poly-L-ornithine (0.05-0.10 microliter injections) or Phaseolus vulgarus (iontophoresed from a 2% solution) into the diagonal band. After survivals of 18-24 hours (HRP) or 5 days (PHAL-L) labeled axon terminals invested the perinuclear zone above the SON. The presence of just a single fiber within the nucleus indicated a minor projection to the SON itself. The HRP-injected material was processed for ultrastructural examination and revealed dense HRP-labeled axon terminals in this perinuclear zone, most often (98%) forming axodendritic appositions. A postembedding colloidal gold technique to visualize GABA-synthesizing terminals revealed that fewer than 5% of these perinuclear HRP-labeled terminals also exhibited GABA-like immunoreactivity. Within the SON, where GABAergic axon terminals are abundant, few (less than 5%) GABAergic terminals contained HRP.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular input to hypothalamic neurosecretory neurons.

In vivo extracellular recordings from rat supraoptic and paraventricular magnocellular neurosecretory cells (MNCs) indicate that putative vasopressin-secreting MNCs may be identified by an abrupt and brief cessation in firing consequent to a transient drug-induced rise in arterial pressure sufficient to activate arterial baroreceptors. In the diagonal band of Broca (DBB), a population of neurons projecting towards the supraoptic nucleus are activated during this drug-induced hypertension. Electrical stimulation in DBB selectively depresses supraoptic vasopressin-secreting MNCs. Intracellular recordings in perfused hypothalamic explants confirm a DBB-evoked bicuculline-sensitive and chloride-dependent postsynaptic inhibition, similar to that associated with the application of gamma-aminobutyric acid (GABA) in approximately half of supraoptic MNCs. Since bicuculline also selectively blocks baroreceptor-induced inhibition in supraoptic MNCs, it is proposed that the depressant baroreflex input to vasopressin-secreting MNCs involves a population of DBB neurons and GABAergic interneurons located close to MNCs. An excitatory and selective input to vasopressin-secreting MNCs follows chemoreceptor activation, possibly mediated by the A1 noradrenergic cell group in the ventrolateral medulla. Another excitatory input to both vasopressin- and oxytocin-secreting MNCs is triggered by circulating angiotensin II and appears to be relayed centrally through an angiotensinergic projection from the subfornical organ.