Multiphasic MR imaging: a new method for direct imaging of pulsatile CSF flow

A new technique is described that allows for the creation of pure pulsatile flow magnetic resonance (MR) images in a single acquisition. Five to 16 electrocardiographically gated images spanning the entire cardiac cycle are obtained with use of a gradient-echo pulse sequence. The section can be varied from 4 mm thick to full thickness projection. Taken singly, each image provides direct assessment of flow direction and velocity. Subtraction of image pairs eliminates signal detected from stationary protons, producing images of pulsatile flow. In this study the technique was used to image the flow of cerebrospinal fluid (CSF) in healthy subjects and in one patient with syringohydromyelia. The data suggest that multiphasic MR imaging provides a powerful means for the noninvasive assessment of CSF pulsatile flow dynamics and may have potential clinical application for the investigation of a variety of abnormalities such as normal pressure hydrocephalus, syrinx, and spinal block.     

Partial characterization of kainic acid-induced striatal dopamine release using in vivo microdialysis

The aim of this study was to characterize interactions between striatal kainate (KA) receptors and dopamine (DA) release using in vivo microdialysis. After insertion of a microdialysis probe and establishment of baseline DA release, each preparation was standardized with a pulse of an iso-osmotic solution of 100 mM KCl in Ringer's solution. DA release following pharmacological manipulation was compared to potassium-induced release and expressed as a percent value. In one group of animals, KA (12.5 mM in Ringer's solution) was administered via the microdialysis probe in 2, 3, 5 or 10 min pulses 30 min following standardization with potassium resulting in release of DA which was15.7 ± 3.9, 30.3 ± 11.3, 67.5 ± 15.0and92.9 ± 19.8% of potassium-induced DA release, respectively. Perfusion of CdCl₂ (0.6 mM in Ringer's solution) 30–45 min prior to a 10 min KA pulse significantly reduced KA-induced DA release compared to control values. Intrastriatal administration of kynurenate (Kyn) attenuated KA-induced DA release in a dose-dependent manner. Levels of DA metabolites in striatal perfusates were significantly reduced following KA administration. This effect was partially reversed by cadmium pretreatment but not affected by Kyn pretreatment. Findings of this study indicate that KA induces striatal DA release in a dose-dependent manner, and this effect is at least partially dependent upon activation of calcium channels. Results also indicate dose-dependent inhibition of KA-induced striatal DA release by the excitatory amino acid receptor antagonist, Kyn, suggesting that this compound interacts with striatal KA receptors and that these receptors are involved with modulating striatal DA release in vivo.     

Male pronuclei formation release of phosphorylation of histone H-3 during decondensation of human sperm nuclei activated in vitro by heparin

The release and phosphorylation/dephosphorylation mechanisms of human spermatozoa histone during nuclei in vitro decondensation by heparin was studied. Washed sperm cells were incubated in the presence of 32P and in the absence or presence of heparin. The results showed an increase in the incorporation of 32P of 20 times greater in the presence of heparin than in the absence of heparin (the control sample). In some cases the incorporation of 32P into histones was confirmed by its isolation. To validate these results a phosphorylation kinetic of isolated sperm histone, used as a substrate, was performed. The amount of 32P was not a linear function of time, and maximal phosphorylation was reached in 60 min. A measurement of 32P incorporated as a function of the amount of histone, shows a linear relationship of up to 50 micrograms of protein, with a rapid saturation thereafter with the incorporation of 220 nm and with a KD = 442 x 10(-6) mol/L. 32P incorporation, independent of exogenous cAMP, was related to alkaline pH but was totally dependent on temperature--with a maximum of 37 degrees C. The only histone released was histone H-3. Phosphorylation/dephosphorylation is involved during male pronuclei formation.     

Nigral degeneration in acquired immune deficiency syndrome (AIDS)

Summary Using stereological techniques we have estimated the volume density of melanin and counted the number of pigmented and non-pigmented neuronal cell bodies in the pars compacta of the substantia nigra of 12 autopsied patients with acquired immune deficiency syndrome (AIDS) who did not have inflammation or necrosis of the midbrain or clinical parkinsonism. The total number of neuronal cell bodies was 25% lower in AIDS (P<0.01) than in 12 age-matched controls, although the volume density of neuronal melanin did not differ from that of controls because the percentage of pigmented cell bodies was higher (P<0.01) and the cell bodies were more fully packed with melanin in AIDS. Also, the expected increase with age of the volume density of neuronal melanin (P<0.02) and the percentage of pigmented neurons (P<0.01) occurred in the controls but not in AIDS patients. Importantly, our histopathological examination showed unequivocal nigral degeneration with neuronal loss, small neuronal cell bodies packed with melanin, reactive astrocytosis and extra-cellular melanin in the AIDS patients but not in controls. Our study shows that a subclinical nigral degeneration is common in AIDS and could possibly explain the heightened suspectibility of some patients to drug-induced parkinsonism.Supported in part by grants from the National Research Institute of Neurology and Psychology and the Lena Price Memorial Fund. Presented in part at the Annual Meeting of the American Academy of Neurology, Chicago, Ill., April 10, 1989     

Small cell carcinoma of the urinary bladder with hypercalcemia

This report describes three cases of undifferentiated small cell carcinoma of the urinary bladder. Their light microscopic appearance is closely akin to the small cell carcinoma of lung. The neoplastic cells exhibit few cytoplasmic dense core neurosecretory granules ultrastructurally and immunoreactivity to enolase. Two patients manifested clinically hypercalcemia which is rare in small cell carcinoma in general and, to the best of our knowledge, has not been described in association with bladder small cell carcinoma.     

Lipoid pneumonia secondary to baby oil aspiration: a case report and review of the literature

Baby oil is a common household product that is frequently used when there are infants or toddlers in the house. However, it is often overlooked as a potential source of danger to these youngsters. In 1983, 36,700 cases of ingestion were reported to the poisoning surveillance and epidemiology branch of the Food and Drug Administration. Topical preparations used in the care of infants accounted for 480 of the cases. Ten percent of these required hospitalization. In 36 cases, the product ingested was baby oil. This figure does not include baby lotions and other skin products with a mineral oil base. Aspiration of mineral oil, the main component of baby oil, has been described as a cause of lipoid pneumonia and oleomas. However, there is very little information in the modern literature concerning acute lipoid pneumonitis in children. We herein present a patient with lipoid pneumonia caused by aspirated baby oil, who followed a severe clinical course. The paucity of information regarding this subject points to the need for increased public and physician awareness of the problem and for their direct participation in the prevention of this potentially fatal condition.     

An approach to As(III) and As(V) bioavailability studies with Caco-2 cells

Foods and drinking water are the main sources of human exposure to inorganic arsenic [As(III) and As(V)]. After oral ingestion, the intestinal epithelium is the first barrier to absorption of these species. A human intestinal cell line (Caco-2) was used to evaluate cell retention and transport of As(III) (15.6–156.0 μM) and/or As(V) (15.4–170.6 μM). Cell monolayer integrity, cell viability, membrane damage and effects on cell metabolism were evaluated. Only the highest concentrations assayed [As(III): 156.0 μM; As(V): 170.6 μM] produced a cytotoxic effect with different cellular targets: As(III) altered the permeability of tight junctions, and As(V) caused uncoupling of the respiratory chain. Retention and transport of As(III) was more efficient than that of As(V). After 4 h of exposure to As(III) or As(V), monolayer retention percentages varied between 0.87–2.28% and 0.14–0.39%, respectively. Transepithelial transport was greater for As(III) (5.82–7.71%) than for As(V) (not detectable—1.55%). The addition of As(III) and As(V) jointly produced a transport rate similar to that observed when they were added independently.