Neuroimaging in Pineal Tumors

BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.     

Transmission of Syphilis by Solid Organ Transplantation

Two organ recipients developed serologic evidence of syphilis infection after renal transplantation from a common deceased donor with a history of treated syphilis. Testing of donor serum for syphilis, which occurred after transplantation, gave results interpreted as consistent with past infection. However, subsequent serologic results in the recipients suggested transmission of infection at transplantation due to active infection of the donor. This may be explained by recent donor re-infection in view of the current syphilis epidemic in the United Kingdom. An initial error in the treatment of recipients further served to highlight unfamiliarity in managing this resurgent infection in the context of organ transplantation.     

Dopamine D2 receptor expression in hippocampus and parahippocampal cortex of rat,cat, and human in relation to tyrosine hydroxylase-immunoreactive fibers

A detailed study comparing the distribution of D2 receptors and tyrosine hydroxylase-immunoreactive fibers in the hippocampus and parahippocampal cortices of the rat, cat, and human was conducted. The distribution of [¹²⁵I]epidepride binding to D2 receptors along the transverse and longitudinal axes of the hippocampus and parahippocampus differed among the species. In rat hippocampus, the number of sites was highest in septal portions of lacunosum-moleculare of CA1 and stratum moleculare of the subiculum. Virtually no binding to D2 receptors existed in the temporal hippocamps. For the cat hippocampus, the highest binding existed in the inner one-third of the molecular layer of the dentate gyrus (DG). There were also significant numbers of D2 receptors in strata radiatum and oriens of the CA subfields, with almost undetectable levels in lacunosum moleculare and subiculum. The number of sites was higher in the septal than temporal hippocampus. In the human hippocampus, highest binding was observed in the molecular layer of DG and the subiculum, with lower levels in strata oriens and lacunosum-moleculare of CA3, and very low binding in CA1. The histochemical demonstration of the pattern of mossy fibers revealed an organization complementary to that of D2 receptors in cat and human. In none of the species was there significant expression of D2 receptors in the entorhinal cortex, except in the caudal extreme of this region in the rat. In that region a trilaminar pattern was exhibited that continued into the perirhinal cortex. A trilaminar pattern of D2 receptor expression was observed in the perirhinal cortex of all species, with the highest values in the external and deep laminae and low expression in the middle laminae. The organization of dopamine fibers was assessed by comparing the distribution of tyrosine hydroxylase-positive and dopamine β-hydroxylase-immunoreactive fibers in these same regions. It revealed consistent mismatches between the pattern of D2 receptor expression and dopaminergic innervation in all three species. The implications for this mismatch are discussed. It is hypothesized that the distribution of D2 receptors, and not of dopamine fibers, determines what neural systems dopamine influences in the hippocampal complex. © 1994 Wiley-Liss, Inc.     

Opioid synapses on vasopressin neurons in the paraventricular and supraoptic nuclei of juvenile monkeys.

Opioid peptide- as well as vasopressin-containing neurons synapse on gonadotropin releasing hormone neurons in juvenile macaques. In this study we performed double-label immunostaining for opioid and vasopressin neurons in the paraventricular and supraoptic nuclei in order to assess their interrelationships. Neuroendocrine neurons in the hypothalamus were prelabeled by microinjection of electron-dense retrograde tracer into the median eminence, and were easily identified in frontal Vibratome sections. Sections through the paraventricular and supraoptic nuclei were immunostained for vasopressin with the peroxidase-antiperoxidase technique, and for opioids using the indirect immunogold method. By light microscopy, opioid-immunoreactive inputs appeared to innervate an average of 39% of the vasopressin neurons in the paraventricular nucleus and 33% in the supraoptic nucleus, and were more prevalent anteriorly. Clusters of opioid afferents formed cup-like calices around major processes of many vasopressin neurons, especially in the paraventricular nucleus. Electron microscopy revealed that these groups of opioid axon terminals made frequent symmetrical and fewer asymmetrical synapses on both neuroendocrine and non-neuroendocrine vasopressinergic cell bodies and dendrites. Our study did not reveal vasopressin-opioid synapses in these hypothalamic nuclei, but this does not preclude the possibility of their existence elsewhere. These results indicate that opioid afferents modulate vasopressin neuronal activity in the monkey paraventricular and supraoptic nuclei. Previous results have suggested that corticotropin releasing hormone acts via vasopressinergic neurons to stimulate opioid neuronal activity and to inhibit gonadotropin releasing hormone release. Taken together, the data suggest that stressful stimuli could initiate a series of neuropeptidergic interactions which ultimately alter pulsatile gonadotropin releasing hormone secretion and thus gonadotropin secretion in primates.     

Gastro-oesophageal reflux disease: Medical or surgical treatment? Report of an interactive workshop

Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper.     

Evidence that difference in size of fraternal twins may originate during early gestation: a case report.

We describe a woman who conceived by in vitro fertilization (IVF) and embryo transfer (ET). Transvaginal ultrasound demonstrated at least 1 week's difference in size of twin gestations from 1 month post-transfer of embryos to delivery. Differences in sac size, crown-rump length, and gestational growth are discussed, as are implications of ultrasound in early pregnancy.