Mechanisms of action of intracerebral neural implants: studies on nigral and striatal grafts to the lesioned striatum

The ability of intracerebrally implanted grafts of neural tissues to promote functional recovery in brain-damaged recipient animals has raised the question of how such implants exert their functional effects. Non-specific, diffuse release of active compounds may be sufficient to restore defective neurotransmission in a denervated brain region, for example, or to provide trophic support for the survival and regeneration of damaged host neurons. The positive therapeutic effects of adrenal medullary grafts, recently reported in patients with Parkinson's disease, are likely to reflect such nonspecific hormonal or neurohumoral mechanisms. Morphological and electrophysiological studies, on the other hand, have shown that grafted fetal neurons can establish extensive efferent synaptic connections with previously denervated or neuron-depleted host brain regions and become at least partially integrated into the host neuronal circuitry. In the damaged nigrostriatal system, grafts of fetal nigral or striatal neurons can restore normal synaptic transmitter release and can also participate in a partial reconstruction of functional neural circuits in the host brain. This indicates that the potential of intracerebral grafts to induce or improve behavioral recovery in brain-damaged recipients rests on the multitude of trophic, neurohumoral and synaptic mechanisms that may allow the implanted tissue to promote host brain function and repair.     

Immediate diagnosis of ventriculits: evaluation of parameters independent of microbiological culture

Background  

Generally accepted reference values in CSF diagnostics are not valid in cerebrospinal fluid (CSF) containing large amounts of blood. Residual blood may obscure ventriculitis as diagnostics largely depend on parameters such as cell count, lactic acid and total protein measurement. We sought to improve the diagnostics by evaluating a cytokine panel and soluble CD62L as markers of ventriculitis. In addition, we tested an algorithm of established parameters to predict ventriculitis in a specific patient collective.     

Potential mechanism for Calvados-related oesophageal cancer

The old Normandian habit of consumption of hot Calvados is associated with an increased risk of oesophageal cancer compared to other alcoholic beverages. The role of alcohol consumption in the risk of oesophageal cancer is well established. The first metabolite of alcohol, acetaldehyde is a potential local carcinogen in humans. Accordingly, different acetaldehyde concentrations in different beverages could account for some of the variations in cancer risk with regard to the type of alcoholic beverage. Eighteen samples of farm-made Calvados were collected in Normandy. Samples of commercially available beverages were purchased, including factory-made Calvados, other spirits, wines, beer and cider. The samples were analysed gas-chromatically for acetaldehyde and ethanol concentrations. All results are expressed as mean ± SD. The mean acetaldehyde concentration of all Calvados samples (1781 ± 861 μM, n = 25) differed highly significantly (p < 0.001) from that of all wine samples (275 ± 236 μM), from all other spirits samples (1251 ± 1155 μM, p < 0.05), and from all beer and cider samples (233 ± 281 μM, p < 0.001). Farm-made Calvados and farm-made cognac had the highest mean acetaldehyde concentration of the measured beverages. The high concentration of acetaldehyde combined with possible effects of the high temperature at which Calvados is consumed could account for the increased risk of Calvados-related oesophageal cancer.     

RB-reconstituted human retinoblastoma cells form RB-positive intraocular and intracerebral but not subcutaneous tumors in scid mice

WERI-Rb 27 human retinoblastoma cells were reconstituted with an intact RB gene by retrovirus-mediated gene transfer, in order to study the phenotypic effects of the protein in vitro and in vivo. Extensive morphological changes were observed, dominated by the formation of multinucleated giant cells. Six weeks after retroviral infection, the giant cells began to die and small cells emerged, resembling the parental non-reconstituted line. They expressed RB and continued to grow, although they showed an increased sensitivity to serum starvation. The original RB-negative cells grew progressively after subcutaneous inoculation into SCID mice, whereas the reconstituted cells failed to grow. RB-positive cells grew progressively in the corpus vitreum of the eye and in the brain, however. The RB-reconstituted cells grew more slowly and were less invasive than the parental cells and cells infected with a firefly luciferase (LUX) gene carrying retrovirus, used as controls. RB-reconstituted cells re-explanted from the intraocular and intracranial tumors continued to express full-length RB protein. RBeye2, an RB-positive cell line established from an eye tumor, was still unable to grow subcutaneously. The reduced tumorigenicity of the RB-reconstituted cells in the subcutaneous space may be due to the influence of locally acting growth-controlling signals or the absence of microenvironment-specific trophic factors. Alternatively, it may reflect the action of residual immune effectors in the SCID mice. If this is the case, these would have to be more effective at the subcutaneous site than in the eye or brain. © 1995 Wiley-Liss, Inc.     

Gonadal steroids, gonadotropins and endometrial histology in postmenopausal women with malignant ovarian tumors

The concentrations of FSH, LH, 17-beta-estradiol (E2), estrone (E1) and progesterone (P) were measured in peripheral and ovarian vein sera obtained at preoperative pelvic angiography from 5 postmenopausal women with malignant ovarian tumors. In 5 others the concentrations of E2, P and testosterone (T) were also measured in ascitic fluid collected at laparotomy. The investigation showed that most of these patients had increased concentrations of E2 and/or E1 and P as well in the peripheral blood. Significant gradients between the ovarian and peripheral vein concentrations were found for E2 and for P. High levels of E2, P and T were found in the ascitic fluid. FSH and LH levels were often lowered in peripheral blood compared with normal menopausal values and a gradient to ovarian tumor venous blood - with lower concentrations in the blood coming from the tumors, was found. Endometrial histology showed signs of steroid stimulation. These cases indicate that malignant ovarian tumors and/or the ovaries harboring them, are often capable of producing different sex steroids. These steroids may be found in the peripheral blood and in the ascitic fluid compartment and therefore may be used as tumor markers. The steroid production is probably not autonomous, but gonadotropin-dependent.     

A novel high-through-put assay for screening of pro-apoptotic drugs

Screening for anti-cancer substances iscommonly conducted using viability assays.An inherent problem with this approach isthat all compounds that are toxic andgrowth inhibitory, irrespective ofmechanism of action, will score positive.It would be beneficial to be able to screenfor compounds that specifically induceapoptosis. We here describe an ELISA-assaybased on a monoclonal antibody (M30) whichrecognizes a neo-epitope on cytokeratin 18exposed after cleavage by caspases duringapoptosis. We show that this assay detectsapoptosis in epithelial cells and that thesensitivity is sufficient for screening inthe 96-well format. We used the M30-ELISAassay to screen 500 low molecular weightcompounds from a chemical library from theNational Cancer Institute and identified 16drugs with strong pro-apoptotic activity,suggesting that the assay is a useful toolfor discovery of pro-apoptotic drugs.     

Neuronal and glial differentiation within expanded glial cultures derived from the lateral and medial ganglionic eminences

Attached glial-like cell cultures were established from the lateral and medial ganglionic eminences (LGE and MGE) and from the neocortex (Cx) of E13.5 mouse embryos, and expanded over four to five passages under epidermal growth factor (EGF) stimulation. Following removal of EGF and serum, we analysed the generation of neurons and glial cells within the cultures. Significant numbers of betaIII-tubulin-positive neurons were generated in both the LGE (about 7% of total cell numbers) and the MGE (around 2%). However, only few betaIII-tubulin-positive cells with neuronal morphologies were detected in the differentiated Cx cultures. The newly formed neurons were to a large extent GABAergic, and many of the MGE-derived, but not the LGE-derived, cells expressed the MGE-marker NKX2.1. Most cells in all cultures still appeared astroglial-like, expressing glial fibrillary acidic protein (GFAP), but in addition, CNPase-positive cells with oligodendroglial morphologies were present in the MGE (0.68%), and, to a lesser extent (0.2%), in the LGE cultures. The present results demonstrate that cells of expanded glial cultures from both the LGE and MGE can give rise to significant and, to a certain extent, region-specific neuronal and glial cell types under differentiating conditions.     

Lactulose reduces intracolonic acetaldehyde concentration and ethanol elimination rate in rats

BACKGROUND: Normal colonic bacteria possessing alcohol dehydrogenase activity can oxidize ethanol to acetaldehyde. Acetaldehyde recently has been shown to be a local carcinogen in humans. The aim of the study was to examine the effect of lactulose feeding on fecal and cecal pH, intracolonic acetaldehyde concentration, and total ethanol elimination rate in rats. METHODS: Sixty Wistar rats were divided into four groups. Groups 2 and 4 received lactulose daily (11 g/kg body weight for 14 days). On days 7 and 14, groups 1 and 2 received ethanol (1.5 g/kg body weight) intraperitoneally, whereas groups 3 and 4 received saline. RESULTS: Fecal and cecal pH values decreased significantly after lactulose treatment compared with the controls. Lactulose feeding reduced the total ethanol elimination rate by 13.8% (257 +/- 0.008 mg/kg/hr vs. 298 +/- 0.003 mg/kg/hr, p < 0.001) and the intracecal acetaldehyde concentration by 66.2% after ethanol (49 +/- 29 microM vs. 145 +/- 47 microM, p = 0.03) compared with the controls. CONCLUSION: Lactulose feeding to rats significantly reduces ethanol elimination rate and intraluminal acetaldehyde concentration in the colon after ethanol administration. This prebiotic thus could be used as an effective agent to block the microbial production of carcinogenic acetaldehyde in the large intestine.     

Effects of selective nitric oxide synthase inhibition on IGF-1, caspases and cytokines in a newborn piglet model of perinatal hypoxia-ischaemia

Selective inhibition of neuronal and inducible nitric oxide synthase (NOS) with 2-iminobiotin previously showed a reduction in brain cell injury. In the present study, we investigated the effects of 2-iminobiotin treatment on insulin-like growth factor-1 (IGF-1) expression, caspase activity and cytokine expression in a newborn piglet model of perinatal hypoxia-ischaemia. Newborn piglets were subjected to 1 h of hypoxia-ischaemia and were treated intravenously with vehicle or 2-iminobiotin. Vehicle-treated piglets showed reduced IGF-1 mRNA expression and increased caspase-3 activity and DNA fragmentation. 2-Iminobiotin treatment, administered immediately upon reperfusion, prevented these observations. No differences in caspase-8 and -9 activity and cytokine [interleukin (IL)-1alpha/beta, IL-6, tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta] mRNA expression were demonstrated between vehicle- and 2-iminobiotin-treated piglets at 24 h following hypoxia-ischaemia. IGF-1 mRNA correlated inversely with caspase-3 and transferase-mediated dUTP-biotin in situ nick end labelling score in the cortex, but positively with caspase-8. Cytokine mRNA did not correlate with IGF-1 mRNA, caspase-3 activity or DNA fragmentation. The present results indicate that the previously demonstrated neuroprotective effect of 2-iminobiotin treatment after perinatal hypoxia-ischaemia coincided with a preservation of the endogenous IGF-1 production and reduced caspase-3 activity, but not with a significant decrease in cytokine production.     

Wernicke's encephalopathy presenting with severe dysphagia: a case report

A 62-year-old man developed dysphagia 4 weeks before the classic symptoms and signs of Wernicke's encephalopathy appeared. Adequate treatment with parenteral thiamine resulted in complete recovery of all symptoms, including his dysphagia. This extraordinary presentation with dysphagia, and the unusual course of the disease, encouraged us to present this case history.