Phaeohyphomycosis due to Alternaria spp. and Phaeosclera dematioides: a histopathological study

A case of phaeohyphomycosis caused by strains of both Alternaria spp. and Phaeosclera dematioides is presented. The biopsy material was studied using histological, immunohistochemical and transmission electron microscopy techniques. The agent's dematiaceous mycelia are composed of thick-walled hyphae, branched and unbranched, with terminal vesicular formations. All the described structures occur alone or in chains within multinuclear giant foreign body-type cells or invading an abscess. Also present are budding forms. Immunostaining of histiocytic inflammatory cells in either. diffuse or granulomatous infiltrates revealed cytoplasmic positivity for lysozyme and Ki-MIP antibody. The lymphocytic infiltrates of the upper corium show predominantly small T lymphocytes (CD3 and CD45RO positive) and absence of CD20-positive B cells. Plasma cells occurring within the infiltrates of the deeper parts show polyclonal expression of both Ig light chains.     

Response of thalamocortical neurons to hypoxia: a whole-cell patch-clamp study

The effect of hypoxia (3-4 min of 95% N2, 5% CO2) on thalamocortical (TC) neurons was investigated using the whole-cell patch-clamp technique in rat dorsal lateral geniculate nucleus slices kept submerged at 32 degreesC. The predominant feature of the response of TC neurons to hypoxia was an increase in input conductance (DeltaGN = 117 +/- 15%, n = 33) that was accompanied by an inward shift in baseline holding current (IBH) at -65 and -57 mV (DeltaIBH = -45 +/- 6 pA, n = 18, and -25 +/- 8 pA, n = 33, respectively) but not at -40 mV. The hypoxia-induced increase in GN (as well as the shift in IBH) was abolished by procedures that are known to block Ih, i.e., bath application of 4-(N-ethyl-N-phenylamino)-1, 2-dimethyl-6-(methylamino)-pyrimidinium chloride (100-300 microM) (DeltaGN = 5 +/- 13%, n = 11) and CsCl (2-3 mM) (DeltaGN = 16 +/- 16%, n = 5), or low [Na+]o (DeltaGN = 10 +/- 10%, n = 5), whereas bath application of BaCl2 (0.1-2.0 mM) had no significant effect (DeltaGN = 128 +/- 14%, n = 8). The hypoxic response was also abolished in low [Ca+2]o (DeltaGN = 25 +/- 16%, DeltaIBH = -6 +/- 8 pA, n = 13), but was unaffected by recording with electrodes containing EGTA (10 mM), BAPTA (10-30 mM), Cs+, or Cl-, as well as in the presence of external tetraethylammonium and 4-aminopyridine. Furthermore, preincubation of the slices with botulinum toxin A (100 nM), which is known to reduce Ca2+-dependent transmitter release, blocked the hypoxic response (DeltaGN = -3 +/- 15%, DeltaIBH = 10 +/- 5 pA, n = 4). We suggest that a positive shift in the voltage-dependence of Ih and a change in its activation kinetics, which transforms it into a fast activating current, may be responsible for the hypoxia-induced changes in GN and IBH, probably via an increase in Ca+2-dependent transmitter release.     

Melanin-containing hydrogel intraocular lenses: a histopathological study in animal eyes

Poly(2-hydroxyethyl methacrylate) hydrogel intraocular lenses, containing adrenochrome-melanin, were manufactured and implanted in animal eyes in order to assess the effect of melanin upon (a) biocompatibility of implants with the eye tissues, and (b) fibrous proliferation of lens epithelium responsible for the opacification of the posterior capsular membrane. An equal number of control lenses were also implanted. The animals were followed up for durations up to two years, and a detailed histopathological examination of the eyes was performed subsequent to their enucleation. The postoperative complications were minor and probably caused by surgical trauma. The study failed to give any indication of the postulated antiproliferative activity of adrenochrome-melanin since minimal capsular opacification occurred in the operated eyes, regardless of the presence of melanin.     

Intravascular ultrasound in endovascular stent-grafts for peripheral aneurysm: a clinical study

The present series of experiments was performed to investigate the influence of acute intracranial hypertension on the upper limit (UL) of cerebral blood flow (CBF) autoregulation. Three groups of eight rats each--one with normal intracranial pressure (ICP) (2 mmHg), one with ICP = 30 mmHg, and one with ICP = 50 mmHg--were investigated. Intracranial hypertension was maintained by continuous infusion of lactated Ringer's solution into the cisterna magna, where the pressure was used as ICP. Cerebral perfusion pressure (CPP), calculated as mean arterial blood pressure (MABP)-ICP, was increased stepwise by continuous intravenous infusion of norepinephrine. CBF was calculated by the intracarotid 133Xe method. In all three groups the corresponding CBF/CPP curve included a plateau where CBF was independent of changes in CPP, showing intact autoregulation. At normal ICP the UL was found at a CPP of 141 +/-2 mmHg, at ICP = 30 mmHg the UL was 103+/-5 mmHg, and at ICP = 50 mmHg the UL was found at 88+/-7 mmHg. This shift of the UL was more pronounced than the shift of the lower limit (LL) of the CBF autoregulation found previously. We conclude that intracranial hypertension is followed by both a shift toward lower CPP values and a narrowing of the autoregulated interval between the LL and the UL.     

Response–effect learning as a major component of implicit serial learning.

Implicit response–effect learning was examined in 2 experiments, using a visual search version of the serial reaction time task introduced by M. J. Nissen and P. Bullemer (1987). In Experiment 1, the relation between the response to the current stimulus and the location of the stimulus on the next trial (i.e., effect) was varied systematically. In Experiment 2, both the frequency of the association between stimuli and responses and the frequency of the association between responses and effects were manipulated. Only the frequency of the response–effect relation influenced learning. These results indicate that response–effect learning is an important component of serial learning. It is argued that response–effect relations constitute the initial implicit component of learning in serial reaction time tasks. From this implicit knowledge, knowledge about the stimulus sequence as well as the response sequence develops later. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of PTA on cerebral vessels in experimental vasospasm: a histopathological study

Although the percutaneous transluminal angioplasty (PTA) is an useful procedure for the treatment of symptomatic vasospasm after subarachnoid hemorrhage, the morphological changes in spastic intracranial vessels after PTA are not yet clear. The purpose of this study was to evaluate the effects of PTA angiographically and histologically. Chronic cerebral vasospasm was induced by producing a blood clot in the subarachnoid space around the top of internal carotid siphon in Japanese monkey. After angiographic recognition of vasospasm, PTA was carried out with silicone microballoon at 1 atmosphere, 3 times for 10 seconds. Angiography after PTA disclosed significant dilatation at the site of PTA, without any significant dilatation of distal spastic vessels. Papaverine hydrochloride was then infused intra-arterially, which resulted in significant dilatation of distal spastic vessels. Upon histological examination, deformation and some denudation of endothelial cells were noted in the intimal layer. At the site of denudation, attachment of platelets was observed despite generalized heparinization. Internal elastic lamina and the media were also stretched and myocytes were deformed and arranged irregularly. These changes were not uniform all over the vascular walls. We conclude that the prolonged effect of PTA may be caused by mechanical damage of endothelial cells and myocytes, and the nonuniformity of histological changes in vascular wall may be a leading cause of its rupture during PTA.     

Miller-Fisher syndrome: electrophysiological serial study of five patients

OBJECTIVE: The object of the present study is to show the spectrum of neurophysiological findings during clinical course of Miller Fisher syndrome (MFS), avoiding the controversy over a combined central and peripheral pathology. PATIENTS AND METHODS: We report five patients with a syndrome of ophthalmoplegia, ataxia and areflexia. A similar episode had been suffered previously by 2 of these patients, 14 and 13 years before. In one of them the second episode evolved to a typical Guillain-Barré syndrome (GBS). Motor and sensory conduction velocity of upper and lower limbs, F waves, blink-reflex and somatosensory evoked potentials were recorded in all cases. Needle electromyography in four and brainstem evoked potentials in three of them and the jaw-reflex in another one. RESULTS: In all patients there was a markedly reduced amplitude of the distal sensory evoked response, and no signs of denervation in the EMG. The other results were variable both interindividually and intraindividually. The severity of abnormalities was also different between different patients. The clinical recovery was always accompanied by a improvement of neurophysiological parameters. CONCLUSIONS: The electrophysiological findings in MFS can be variable but they appear always related with the clinical symptomatology. We report for the first time a case in whom the jaw-reflex was abnormal whereas the blink-reflex was normal.     

Skin mini-erosion sampling technique: feasibility study with regard to serial glucose measurement

The effect of the Aconitum alkaloids aconitine, 3-acetylaconitine, lappaconitine, and N-desacetyllappaconitine to inhibit [3H]noradrenaline uptake was investigated in rat hippocampal synaptosomes. Aconitine and 3-acetylaconitine, which are known to activate sodium channels, had comparable inhibitory potencies and yielded Ki (inhibitor constant) values of 230 +/- 66 nM and 316 +/- 96 nM, respectively. In contrast, lappaconitine and N-desacetyllappaconitine failed to inhibit [3H]noradrenaline uptake. When either lappaconitine or N-desacetyllappaconitine was applied in combination with aconitine, [3H]noradrenaline uptake was not affected. The sodium channel blocker tetrodotoxin enhanced [3H]noradrenaline uptake, whereas uptake was completely blocked in sodium-free incubation medium. The inhibitory action of aconitine and 3-acetylaconitine on [3H]noradrenaline uptake was blocked by addition of tetrodotoxin. Patch clamp studies performed on cultured rat hippocampal neurons revealed an inhibitory action of lappaconitine and N-desacetyllappaconitine on whole cell sodium currents. It is concluded that the blockade of [3H]noradrenaline uptake evoked by aconitine and 3-acetylaconitine is mediated indirectly by an increased sodium concentration in the synaptosomes.     

Brain parenchyma/pO2 catheter interface: a histopathological study in the rat

Local cerebral oxygenation can be monitored continuously using an intraparenchymal Clark-type pO2 sensitive catheter. Measured values of brain tissue pO2 (PbrO2) not only depend on the clinically interesting balance between oxygen offer and demand, but also on catheter properties and characteristics of the probe tissue interface. Microdamage surrounding pO2-sensitive needles, inserted into various tissues, has been reported; we evaluated histologic changes at the probe tissue interface after insertion of pO2 probes, suitable for clinical use, in the rat brain. The effect of insertion of the probe itself (mechanical damage), the application of micropotential during the measurements, and the effect of time was evaluated using digital image analysis of H&E-stained histological slices. Surrounding the probe tract, a zone of edema with an average radius of 126.8 microm was seen; microhemorrhages with an average surface area of 56.2 x 10(3) microm2 were observed in nearly all cases. The area of edema and the presence of microhemorrhages were not influenced by performed measurements or by time. Intraventricular blood was observed in 10 of 19 rats studied. Measured low PbrO2 values were related to the presence of a microhemorrhage in either probe tract or ventricles. Tissue damage due to the measurements is negligible, and the amount of edema itself does not influence the accuracy or response time of the pO2 probe. Low PbrO2 readings, however, could be caused by local microhemorrhages, undetectable on CT or MRI.     

Human defunctionalized colon: a histopathological and pharmacological study of muscularis propria in resection specimens

Despite the regression of "diversion colitis," temporary functional disorders after bowel continuity restoration could be caused by changes in the smooth muscle of excluded segments; however, studies on the muscularis propria have yielded contradictory results. This study was aimed at evaluating possible histopathological changes in muscular layers and motility of the defunctionalized human colon. Ten patients with defunctionalized colorectum (group A) and 10 controls (group B) underwent restorative or primary resection surgery. Strips were taken proximal to the colostomy (specimens A1) and the defunctionalized segment (specimens A2), and from the proximal (specimens B1) and distal extremity (specimens B2) of resected colons. Measurements of the thickness of the muscularis propria and of the volume density of the myenteric plexus, as well as of spontaneous motility and responses to electrical and pharmacological stimulation were taken. The muscularis propria was thicker in A2 than in A1 specimens (P = 0.004) and in B2 than in B1 specimens (P = 0.007). No differences were recorded either in the myenteric plexus volume density or in colonic motility. No differences were recorded in intergroup comparisons. As no structural or functional changes related to defunctionalization were found, clinical disorders after colorectal restoration could rather result from underlying colonic pathology and/or incomplete distal colon resection.     

Simultaneous operation of intra-descending aorta bypass grafting and brachiocephalic artery reconstruction in a patient of aortitis syndrome

OBJECTIVE: To determine the intracavernous partial oxygen pressure in different etiological groups of erectile dysfunction: psychogenic (control group), arterial and veno-occlusive and the value of intracavernous gasometry as an indicator of the degree of severity of impotence. METHODS: A total of 16 patients were evaluated according to the diagnostic protocol utilized to determine the etiology of erectile dysfunction. Intracavernous blood samples were obtained during the initial phase of gasometry and PO2 was determined by standard gasometric methods. RESULTS: After injection of the vasoactive drug, the mean intracavernous PO2 was 92.4 +/- 1.27 for the control group, 62.2 +/- 0.85 for the group with arterial impotence, and 76.8 +/- 1.45 for the group with venous impotence, demonstrating a statistically significant difference (p < 0.01). CONCLUSIONS: Intracavernous gasometry, in combination with other diagnostic tests, is useful for evaluating the degree of severity of erectile dysfunction. The reduction in cavernous oxygen tension, which induces cavernous tissue fibrosis, can be considered to be a common mechanism in arterial and venous impotence.     

From segmental glomerulosclerosis to total nephron degeneration and interstitial fibrosis: a histopathological study in rat models and human glomerulopathies

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is consistently associated with tubular degeneration and interstitial fibrosis, altogether, accounting for the progressive decline in renal function. The mechanisms which link glomerular injury to tubulo-interstitial fibrosis are controversial. The present study describes the step-by-step sequence of histopathological events, i.e. the evolution of the injury from the initial lesion in the glomerulus to total nephron destruction. METHODS: The investigation was performed in male hypertensive Fawn-hooded rats (6-, 9-, and 12-month-old) and 14-month-old Milan normotensive rats. The kidneys were fixed by in vivo perfusion and processed for structural investigation. Autopsy materials from human cases of focal segmental glomerulosclerosis and diabetic nephropathy were also examined. RESULTS: FSGS as seen in rat models consists of collapsed and hyalinized capillaries and mesangial portions which are included within a synechia between the glomerular tuft and Bowman's capsule. In addition, a synechia generally contains glomerular capillaries which are perfused and continue to filter with the filtrate being delivered into the interstitium rather than into Bowman's capsular space. Such filtration creates a paraglomerular space on the outer aspect of the parietal epithelium. This space becomes separated from the interstitium by a dense layer of sheet-like fibroblast processes. Associated with the progression to global sclerosis, this space spreads around the entire circumference of a glomerulus; all 'sclerotic' tuft portions are eventually contained in this space. Starting from the urinary pole this process also involves the proximal tubule, initially by expanding the tubular basement membrane (TBM) and later, by separating the TBM from its epithelium, thus creating a peritubular space by misdirected filtrate spreading. Similar to the situation observed at the glomerulus this space becomes separated from the interstitium by a layer of fibroblast processes. The final degeneration of the nephron occurs via two pathways. Pathway I whereby development to global sclerosis is dominant or develops concurrently with tubular degeneration, eventually terminating in global and cylindrical remnants of extracellular matrix surrounded by abundant fibrous tissue. Pathway II where the degeneration of the tubule is ahead of damage progression in the glomerulus leading to atubular glomerular cysts. CONCLUSION: The present study suggests that severely injured glomeruli may continue to filter with the filtrate spreading along interstitial routes. Fluid added locally to the interstitium from such 'extraterritorial' glomerular capillaries probably is quite different in quantity and composition compared to that from interstitial capillaries. We propose that this kind of abnormal addition of fluid to the interstitium is the essential mechanism accounting for interstitial progression of the disease. Similar histopathological phenomena in human kidneys with focal segmental glomerulosclerosis suggest that the pathogenetic pathways defined in the rat models operate in human disease as well.     

Brain neurotoxicity of Penitrem A: electrophysiological, behavioral and histopathological study

The neurotoxicity of Penitrem A (PA) in rats was assessed against neurophysiological, behavioral and histopathological parameters. Animals were acutely given intracerebroventricular (22-45 mg) or intraperitoneal injections (0.5-1.5 mg/kg) of PA. A typical trembling syndrome associated with PA was always noted. Depending on the dose administered, animals may convulse and eventually die (1-1.5 mg/kg). PA-induced transient alterations of the EEG involving an increase in the frequency and voltage of electrical activity recorded from the cerebral cortex. Hippocampal activity was not modified and some pathologic activities may be recorded at the thalamus. Generally these EEG alterations disappeared at d 3 after the injection and the animals progressively recovered. However in the most severe cases, neuromotor disturbances were maintained at d 7 (rotarod test). Coronal sections of the brain at the striatal, thalamic, hippocampal and pons levels mainly revealed that PA was able to induce dose related injuries in the cerebellum with massive degeneration of Purkinje cells and a significant vacuolization within the molecular layer. The neurotoxic mechanism remains unclear. Action of the mycotoxin on the cerebello-thalamo-cortical tract is discussed.     

Cultivation and grafting of human keratinocytes on a poly(hydroxyethyl methacrylate) support to the wound bed: a clinical study

Cultured epithelial sheets on a textile support are used for the treatment of seriously burned patients. In this study we demonstrate a new procedure for the grafting of keratinocytes directly on a polymer cultivation support. This procedure is much easier in comparison with classical techniques, and encouraging results of clinical trials demonstrate the improved healing of the wound bed after the use of this procedure. There is no difference in the cytokeratine pattern (LP-34, cytokeratin-10) of the reconstructed epidermis and normal human skin.     

Time serial study of orthostatic cardiovascular regulations

In a repeated measurement design (16 times during 8 weeks) active orthostasis was investigated in a sample of twenty male students, utilizing a tilt table. Additional data included cardiovascular and pulmonary tests, psychological scales, items from a diary and meterorological data. Analysis of orthostatic time-series was carried out with hierarchical grouping analysis for heart rate and blood pressure. Results indicated three intraindividual patterns of orthostatic reaction called normo-, hyper- and hyporeactive. These patterns are independent of the known interindividual orthostatic reaction types. Analysis of variance of the described patterns revealed differences for physiological and meteorological data and some items of the diary. These results have been crossvalidated.