Analytical interference of lipid parenteral feeding with the determination of methemoglobin levels by an autoanalyzer

We report here an unusual cause of analytical interference observed in methemoglobin values of patients parenterally given nutritive lipid emulsions. In these patients, harboured in intensive care department, T Hb, % O2 Hb, % COHb, Met Hb values are systematically measured using IL 282 CO-Oximeter autoanalyser in addition to daily blood gas determination (pH, PaCO2, PaO2). An increase in % Met Hb rate up to 10-20% was observed in lipid emulsions receiving patients. We first verified that washing red blood cells with saline instantaneously lowers Met Hb values to less than 1%. The mechanism of this interference was addressed by performing three Met Hb determination methods in normal blood in vitro added with variable amounts of lipid emulsions: CO-Oximeter determination, classical Evelyn Malloy method, analysis of continuous absorption spectra between 480 and 640 nm. Results corroborate the spectral origin of the analytical interference observed with CO-Oximeter and leading to false positive values. Blood lipids increase unspecifically the wave length proportional absorption between 480 and 640 nm. Evelyn Malloy's technique suppresses this interference since it uses the ratio of differences in optical densities. Our results emphasize the necessity of knowing patients therapeutics when performing laboratory investigations.     

Discharge properties of neurons in the monkey thalamus tested with angular acceleration,eye movement and visual stimuli

Summary Monkeys were trained to make visually evoked eye movements while undergoing simultaneous head rotation. Single units were recorded in the pregeniculate nucleus (PGN). PGN neurons discharged during each saccade, but there was no change in activity with horizontal head acceleration or with various combinations of head and smooth pursuit eye movements as previously described in the cat. Therefore, the anatomical homology between LGN_v and PGN does not appear to have a neurophysiological basis. Neurons in the oral part of VPL or occasionally in VPI discharged as a function of head velocity but not with saccades, smooth pursuit or fixation eye movements, nor after brief light flashes or during smooth pursuit across structured backgrounds. This suggests that VPL_o and VPI are only vestibular relay nuclei and not concerned with vestibular/visual or vestibular/oculomotor interactions.It is a pleasure to acknowledge the histological talents of Donna Simmons, the veterinary care provided by Stan Crossman and Margaret Price, the surgical assistance of Doug Hasund, the secretarial help of Jean Scalf, and the editorial comments of Kate Schmitt.On leave from Laboratoire de Neuropsychologie Expérimentale, INSERM U 94, 16, av. Doyen Lépine, 69500 Bron, FranceThis research was supported by grants RR00166, GM00260 and EY00745 from the National Institutes of Health, U. S. Public Health Service, and by a grant from INSERM.     

Retinotopic organization of extra-retinal saccade-related input to the visual cortex in the cat

Summary Single unit activity of 842 cells has been recorded in cat visual cortex and analyzed with respect to vestibular induced, and spontaneous saccadic eye movements performed in the dark. This study has been done in awake, chronically implanted cats, subsequently placed in acute conditions to achieve the precise retinotopic mapping of the cortical areas previously investigated.In areas 17 and 18, respectively, 27% and 24% of the cells tested were influenced by horizontal saccadic eye movements in the dark (E. M. cells). In the Clare-Bishop area, the proportion of E. M. cells was 12%, while only 2% of such cells were found in areas 19 and 21.The distribution of E.M. cells in areas 17 and 18 with respect to retinotopy showed that E.M. cells were more numerous in the cortical zones devoted to the representation of the area centralis (38% in area 17, 27% in area 18) than in the zones subserving the periphery of the visual field (17% and 12%, respectively).Two of the characteristics of E. M. cell activations appear dependant on the retinotopic organization. First, a larger number of E.M. cells presenting an asymmetry in their responses to horizontal saccadic eye movements in opposite directions (directional E.M. cells) were encountered in the cortical representation of the peripheral visual field. 53% of E. M. cells recorded in area 17 and 71% in area 18 were directional in the cortex corresponding to the peripheral visual field. This percentage was of 23% and 25% respectively in the cortex devoted to area centralis. Second, E.M. cells were found to have a latency from the onset of the saccade systematically larger than 100 ms (i.e, they discharged at, or after the end of the eye movement) if they were located in the cortical representation of the area centralis, while E.M. cells related to the peripheral visual field displayed a wider range of latencies (0–240 ms).Results obtained in Clare Bishop area, although limited to the representation of the peripheral visual field, were quantitatively and qualitatively similar to those observed in the homologous retinotopic zones of areas 17 and 18.It is concluded that an extra-retinal input related to oculomotor activity is sent to the cat visual cortex and is organized, at least in areas 17 and 18, with respect to the retinotopic representation of the visual field. These data support the hypothesis of a functional duality between central and peripheral vision and are discussed in the context of visual-oculomotor integration.Supported by INSERM (C.R.L. 79-53336)     

Chlorpyrifos alters functional integrity and structure of an in vitro BBB model: co-cultures of bovine endothelial cells and neonatal rat astrocytes

The blood-brain barrier (BBB) is a structural and functional interface between the circulatory system and the brain. Organophosphorous compounds such as chlorpyrifos (CPF) may cross the BBB and disrupt BBB integrity and function. To determine events that may contribute to CPF toxicity, we used an in vitro BBB model in which bovine microvascular endothelial cells (BMEC) and neonatal rat astrocytes were co-cultured. We hypothesized that CPF is metabolized by the BBB leading to an inhibition of esterase activity and a disruption of the BBB. The co-culturing of BMECs and astrocytes resulted in tight junction formation as determined by electron microscopy, electrical resistance and western blot analysis of two tight junction-associated proteins (ZO-1 and e-cadherin). We observed time dependent increases in ZO-1 and e-cadherin expression and electrical resistance during BBB formation, which were maximal after 9-13 days of co-culturing. The CPF concentration and production of its metabolites were monitored by HPLC following 24 h exposure to CPF on the luminal side of the BBB. We found that the BBB metabolized CPF, with the metabolite 2,3,6-trichloro-2-pyridinol being the major product. CPF and its metabolites were detected on the abluminal side of the BBB suggesting that CPF crossed this barrier. CPF was also detected intracellularly and on the membrane inserts. At tested concentrations (0.1-10 microM), CPF inhibited both carboxylesterase (CaE) and cholinesterase (ChE) activities in BMECs by 43-100%, while CPF-oxon totally inhibited CaE and ChE activity in concentrations as low as 0.1 microM. CPF also caused a concentration-dependent decrease in electrical resistance, with significant inhibition observed at 1 nM and complete loss at 1 microM. These data show that low concentrations of CPF and its metabolites are present within the BBB. CPF and its metabolites, especially CPF-oxon, contribute to the inhibition of CaE and ChE activity, as well as the alteration of BBB integrity and structure.     

A novel series of highly potent benzimidazole-based microsomal triglyceride transfer protein inhibitors

A series of benzimidazole-based analogues of the potent MTP inhibitor BMS-201038 were discovered. Incorporation of an unsubstituted benzimidazole moiety in place of a piperidine group afforded potent inhibitors of MTP in vitro which were weakly active in vivo. Appropriate substitution on the benzimidazole ring, especially with small alkyl groups, led to dramatic increases in potency, both in a cellular assay of apoB secretion and especially in animal models of cholesterol lowering. The most potent in this series, 3g (BMS-212122), was significantly more potent than BMS-201038 in reducing plasma lipids (cholesterol, VLDL/LDL, TG) in both hamsters and cynomolgus monkeys.     

Suicide attempt in ulcerative colitis patient after 4 months of infliximab therapy — A case report

In the summary of product characteristics of infliximab (IFX), psychiatric side effects are reported to be rare, and in literature only limited data exist. This report presents a case of a patient with ulcerative colitis who developed a depression with psychotic symptoms during IFX therapy and made a suicide attempt 4 months after the initiation of therapy. Although the time between start of IFX therapy and onset of symptoms could suggest a correlation, this, of course, does not prove that IFX was the causative factor for his depression and suicide attempt.     

Value of cyclofenil in the inhibition of lactation. Efficacy compared to bromocriptine

The inhibitory effects of cyclofenil and bromocriptine on lactation as well as FSH, prolactin and estradiol levels have been compared in control and treated females. The clinical activity of cyclofenil was lower than that of bromocriptine but was virtually free of side-effects. Cyclofenil and bromocriptine only presented similar hormonal effects at the 20th day ; this suggests that the mechanism of action of cyclofenil is more linked to secondary increases in estrogen levels than to a primary effect. Cyclofenil is of particular value in cases of vascular hypersensitivity yo ergot derivatives and for toxemic patients treated with beta-blockers.     

Tooth injuries during intubation: a new preventive device

This study analyses 126 cases of dental injuries occurring during endotracheal intubation, reported to the service of litigations of the hospitals in Lyon over a ten-year period, and giving rise to a complaint. The overall rate was 1 out of 4,000 cases of intubation. The true incidence may be greater. As expected, the upper jaw teeth are most often involved, especially the left incisors. Among them 24.3% of the involved teeth were normal. Dental fractures were the most common lesion, together with total or partial dislocations. A questionnaire was sent to 534 anaesthetists to assess the main difficulties which they encounter when carrying out endotracheal intubation. The results of this enquiry demonstrated that anaesthetists were very aware of dental risks when carrying out intubation, and that there was a lack of efficient protective measures. Among them 81.2% claimed they would use a protective device from time to time, and 17.4% routinely, if one were available. Therefore we designed such a device. It is gutter-shaped, made with two different plastics, the more rigid one being on the outside. It fits over the upper jaw teeth. There is an indentation in the front, to check whether the device is placed correctly. The inner surface is made of foam which dulls the pressure which may be exerted on the device during intubation. This device was tested in 108 patients. Intubation was easy with the device in place in 73.2% of patients; mouth opening was reduced by a mean of 4.2 +/- 0.5 mm. The device made intubation more difficult, and even impossible, in patients whose mouth opened no more than 3.5 cm.(ABSTRACT TRUNCATED AT 250 WORDS)