Visual illusion induced by sound

We present the first cross-modal modification of visual perception which involves a phenomenological change in the quality-as opposed to a small, gradual, or quantitative change-of the percept of a non-ambiguous visual stimulus. We report a visual illusion which is induced by sound: when a single flash of light is accompanied by multiple auditory beeps, the single flash is perceived as multiple flashes. We present two experiments as well as several observations which establish that this alteration of the visual percept is due to cross-modal perceptual interactions as opposed to cognitive, attentional, or other origins. The results of the second experiment also reveal that the temporal window of these audio-visual interactions is approximately 100 ms.     

B Cell lymphoma of the brain stem masquerading as myasthenia

A 54 year old man is described with signs compatible with ocular myasthenia gravis and an apparent excellent response to pyridostigmine. Subsequent clinical progression and further investigation suggested the presence of an inflammatory brain stem lesion, which responded to corticosteroid therapy. Clinical relapse, including the development of central neurogenic hyperventilation, led to a brain stem biopsy, confirming a diagnosis of B cell lymphoma. This case illustrates the propensity of primary CNS lymphoma (PCNSL) to mimic other conditions. Brain MRI is mandatory in presumed "test negative" ocular myasthenia with atypical clinical findings. Spontaneous regression of PCNSL or response to corticosteroids is common and should not mitigate against the diagnosis. Histopathological confirmation should ideally be made before starting therapy, as this may obscure or delay the correct diagnosis. Although PCNSL is rare, it must be considered in all patients with brain stem syndromes, and in all patients 50 years or older with contrast enhancing focal lesions.     

Case report. An unusual case of cutaneous sporotrichosis and its response to weekly fluconazole

Cutaneous sporotrichosis is clinically divided into two main types: lymphocutaneous and fixed plaque type. Our report represents an unusual case with both types simultaneously. Fluconazole 150 mg once weekly was used as the treatment. The fixed type lesions responded very well and were healed after 4 months, but the lymphocutaneous lesions were not controlled even after 6 months of the treatment.     

Pharmacological evaluation of the beta-adrenoceptor agonist properties of N-benzyl substituted trimetoquinol analogues

The beta 1- and beta 2-adrenoceptor agonist properties of trimetoquinol (TMQ, I) and N-benzyl ring substituted TMQ analogues (II, 4'-methylbenzylTMQ; III, 4'-chloro-benzylTMQ; IV, 4'-methoxybenzylTMQ; V, 4'-nitrobenzylTMQ; VI, 3',4'-dichlorobenzylTMQ; and VII, 4'-aminobenzylTMQ) were studied in guinea pig atria and trachea. All compounds gave concentration-dependent responses in atria and trachea, and the rank order of beta-adrenoceptor agonist potency was I greater than VII greater than II greater than V greater than IV greater than VI greater than III and I greater than VII greater than IV = VI greater than V greater than III greater than II, respectively. Whereas the N-benzyl substitution reduced potency for beta-agonist activity, the beta 2/beta 1-selectivity ratio was enhanced by addition of groups to the N-benzyl ring, and the rank order of beta 2-selectivity was VI (10-fold) greater than III (8-fold) = IV (8-fold) greater than VII (3-fold) greater than V = I greater than II. The results show that varying the nature of substituents on the N-benzyl ring of TMQ produces compounds which retain greater beta 2-selectivity.     

Effects of nitric oxide on gentamicin toxicity in isolated perfused rat kidneys

BACKGROUND: There have been many studies in recent years concerning the role of nitric oxide (NO) in acute renal failure (ARF). In this study, the effects of the inhibition or the induction of NO synthase (NOS) on gentamicin-induced ARF was investigated in isolated perfused rat kidneys. METHODS: Kidneys from male Sprague-Dawley rats were perfused in situ for 90 min. Perfusion was conducted in the presence of inulin (60 mg/dL in perfusion buffer) as a glomerular filtration rate (GFR) marker. Six groups (total: 42 rats) were studied: group 1, controls with no treatment; group 2, L-arginine (2 mM in perfusate); group 3, L-nitro-arginine-methyl ester (L-NAME, 0.1 mM in perfusate); group 4, gentamicin (GM, 0.5 mg/mL in perfusate); group 5, GM + L-arginine (same dose as groups 2 and 4) and; group 6, GM + L-NAME (same dose as groups 3 and 4). Cell injury was assessed by measuring N-acetyl-beta-D-glucosaminidase (NAG), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) activity in urine. RESULTS: L-arginine prevented, whereas L-NAME enhanced, GM-induced enzyme release and GFR reduction. Histological studies showed that GM-treated kidneys had clear signs of tubular damage and this damage was increased by simultaneous L-NAME and GM administration. CONCLUSION: This study suggests that NO formation could prevent the GM-induced nephrotoxicity in this ARF model.