Comparison between conventional and neuronavigated strategies to assess corticospinal responsiveness in unfatigued and fatigued knee-extensor muscles.

In studying neuromuscular fatigability, researchers commonly use functional criteria to position and hold the transcranial magnetic stimulation (TMS) coil during testing sessions. This could influence the magnitude of corticospinal excitability and inhibition responses due to imprecise and unsteady positions of the coil. To reduce coil position and orientation variability, neuronavigated TMS (nTMS) could be used. We evaluated the accuracy of nTMS and a standardized function-guided procedure for maintaining TMS coil position both in unfatigued and fatigued knee extensors. Eighteen participants (10F/8M) volunteered in two identical and randomized sessions. Maximal and submaximal neuromuscular evaluations were performed with TMS three times before (PRE_1) and three times after (PRE_2) a 2 min resting session and one time immediately after (POST) a 2-min sustained maximal voluntary isometric contraction (MVIC). The located "hotspot" [the location that evoked the largest motor-evoked potential (MEP) responses in the rectus femoris] was maintained either with or without nTMS. MEP, silent period (SP) and the distance between the "hotspot" and the actual coil position were recorded. A time × contraction intensity × testing session × muscle interaction was not observed for MEP, SP, and distance. Bland-Altman plots presented adequate agreements for MEP and SP. Spatial accuracy of TMS coil position over the motor cortex did not influence corticospinal excitability and inhibition in unfatigued and fatigued knee extensors. The variability in MEP and SP responses may be due to spontaneous fluctuations in corticospinal excitability and inhibition, and it is not altered by the spatial stability of the stimulation point.

Intermittent contact hydration scanning probe microscopy.

Hydration scanning probe microscopy is a technique similar to scanning tunneling microscopy, in which the probe current, sustained by the slight surface conduction of a thin hydration layer covering an insulating support surface, is essentially electrochemical in nature instead of electronic tunneling. Such a technique allows the imaging of a great variety of samples, including insulators, provided that they are hydrophilic, as well as the study of molecular samples of biological interest (such as DNA) fixed on a suitable supporting surface. The main problem to obtain stable and reproducible images comes from the very critical determination of the operating conditions under which the probe-hydration layer interaction does not lead to the formation of a relatively large water meniscus. It has been suggested that this issue can be removed by adding a high frequency oscillation to the probe movement, as in tapping atomic force microscopy. Meniscus formation and breakup have been investigated in order to determine the best values for the amplitude and the frequency of the oscillation. Results obtained in this mode are discussed in comparison with the usual continuous contact mode.

Implementation on a desktop computer of the real time feedback control loop of a scanning probe microscope.

A software package has been developed to implement the real time feedback control loop needed in scanning probe microscopy on a general purpose desktop computer of the current high-speed/multicore generation. The main features of the implementation of both the feedback loop and the control of the experiment on the same computer are discussed. The package can work with several general purpose data acquisition boards and can be extended in a modular way to further board models; timing performance has been tested with several hardware configurations and some applications common in scanning probe microscopy. The package is available under an Open Source license.

A study of the ionic conduction of mica surface by admittance spectroscopy.

The ionic conduction on the surface of humid mica has been analyzed by admittance spectroscopy as a function of relative humidity for different surface treatments. Measurements at low frequency indicate that water adsorption proceeds first in the form of a strongly adsorbed uniform thin layer, then with the formation of highly inhomogeneous thick aggregates.

Microbial community structure in three deep-sea carbonate crusts.

Carbonate crusts in marine environments can act as sinks for carbon dioxide. Therefore, understanding carbonate crust formation could be important for understanding global warming. In the present study, the microbial communities of three carbonate crust samples from deep-sea mud volcanoes in the eastern Mediterranean were characterized by sequencing 16S ribosomal RNA (rRNA) genes amplified from DNA directly retrieved from the samples. In combination with the mineralogical composition of the crusts and lipid analyses, sequence data were used to assess the possible role of prokaryotes in crust formation. Collectively, the obtained data showed the presence of highly diverse communities, which were distinct in each of the carbonate crusts studied. Bacterial 16S rRNA gene sequences were found in all crusts and the majority was classified as alpha-, gamma-, and delta- Proteobacteria. Interestingly, sequences of Proteobacteria related to Halomonas and Halovibrio sp., which can play an active role in carbonate mineral formation, were present in all crusts. Archaeal 16S rRNA gene sequences were retrieved from two of the crusts studied. Several of those were closely related to archaeal sequences of organisms that have previously been linked to the anaerobic oxidation of methane (AOM). However, the majority of archaeal sequences were not related to sequences of organisms known to be involved in AOM. In combination with the strongly negative delta 13C values of archaeal lipids, these results open the possibility that organisms with a role in AOM may be more diverse within the Archaea than previously suggested. Different communities found in the crusts could carry out similar processes that might play a role in carbonate crust formation.

Intercalation of the radical scavenger ferulic acid in hydrotalcite-like anionic clays.

Hydrotalcite is a biocompatible lamellar anionic clay formed by double hydroxide layers with a metal cation coordinating four OH groups. The different layers are held together by anionic hosts that can be replaced by a simple ion-exchange process. The synthetic Mg-Al-hydrotalcite was used to intercalate ferulic acid, a compound that shows antioxidant properties due to its free radical scavenger capacity. Analysis of the intercalated compound showed a good intercalation percentage (35.53%) accompanied by an increase of the interlayer space from 7.8A (chloride form) to 17.1A due to the presence of the ferulate. The intercalation product was stable in water, did not show any significant degradation after UV-irradiation, had a higher capacity of UV absorption in comparison to both the pure ferulic acid and ferulic acid-hydrotalcite chloride physical mixture. The intercalated compound was formulated in a siliconic cream and the ferulate in vitro release profiles determined.

Ultrasonography in the early diagnosis of psoriasis-associated enthesopathy.

The aim of the present study was to detect entheseal abnormalities by means of ultrasonography (US) in patients with psoriasis. We evaluated 24 patients with psoriasis who underwent clinical and ultrasonographic examination of both lower limbs at the calcaneal insertions of the Achilles tendons and at the flexor and extensor tendons of all fingers of the hand. Fourteen patients with psoriatic arthritis were used as controls. US was performed using a real-time scanner (ATL SDI 3000) with a 5-12 MHz linear array transducer. Longitudinal and transverse scans of the talocrural joints, Achilles tendons and both the flexor and extensor tendons of the fingers of both hands were obtained at rest and during active and passive movements. On clinical examination no entheseal site was abnormal, but on US examination 33% of patients showed abnormalities. In particular, six psoriasis patients (25%) who were asymptomatic showed effusion around the extensor tendon of the first digit of the left hand and around the extensor tendon of the third and fourth digits of both hands; two patients (8.3%) showed a hypoechoic nodular formation of the flexor tendon sheath of the left hand. We conclude that entheseal abnormalities not detected at clinical examination were present in 33% of patients with psoriasis who underwent US examination. Therefore, we suggest the routine use of ultrasonography in the early diagnosis and in treatment and follow-up of patients with tendon enthesopathy, since these factors may have implications for therapy.

[Urinary hydrometrocolpos by persistent urogenital sinus; prenatal diagnosis and neonatal management]. / Idrometrocolpo urinoso da persistenza del seno urogenitale: diagnosi prenatale e management neonatale.

Urogenital Sinus (UGS) malformation can be ascribed to an arrest of normal embryonic vaginal development. Neonates with UGS frequently have ambiguous genitalia, rarely the vulva may be normal. The aim of this work is to define the role of prenatal sonography in the diagnosis of UGS associated with hydrocolpos and/or hydrometrocolpos. The Authors report their experience on 3 cases of UGS without ambiguous genitalia with hydrometrocolpos, in which prenatal sonography had shown a cystic dilatation in the pelvis. After birth the 3 neonates presented with female genitalia and a single orifice between the labia. The pelvis sonography showed in all the cases an hydrometrocolpos with a large vagina and a compressed and anteriorly located bladder. Voiding cystourethrogram, genitography and genitoscopy confirmed the presence of an UGS with urinary retention inside the vagina and stenosis of the distal portion of the vagina itself. An early drainage of the capacious vagina was performed in the three patients. There are very few reports in the literature of UGS with hydrometrocolpos diagnosed in utero. The cystic dilatation of the vagina is always misdiagnosed with a distended bladder. In utero, infact, the bladder can not be identified being displaced anteriorly by the vagina. The presence of a fluid-debris level inside the cystic anechoic mass must be considered a crucial finding. Multiple echoes are due to vaginal secretions. Prenatal ultrasound has then a definitive role in detecting an obstructed genital tract. This allows to rapidly drain the vagina relieving urinary tract obstruction.

A new GABA-A receptor subtype coupled with Ca++/Cl- synporter modulates aminergic release from rat brain neuron terminals.

The aim of the present study was to give a better characterization of GABA receptors that modulate aminergic release. GABA or muscimol (15 microM) increased basal noradrenaline (3H-NA) release but reduced the following K+-evoked 3H-NA release in the synaptosomes from rat cerebellar cortex. Bicuculline and picrotoxin counteracted these two effects. The same GABA modulation resulted to operate also on dopaminergic and serotoninergic neuron terminals. The increased basal noradrenaline release resulted to be both calcium and chloride dependent and associated with an increased entry of 45Ca++ into the synaptosomes. We therefore advance the hypothesis of an involvement of a Cl-/Ca++ synporter system coupled to the receptor. Baclofen also reduced the K+-evoked 3H-NA release, but did not increase basal 3H-NA release; moreover, the interaction of baclofen G with GABA-B receptors resulted to be associated with the inhibition of 45Ca++ entry into synaptosomes. GABA-B receptors resulted to be present also on serotoninergic but not on dopaminergic neuron terminals. The GABA-C receptor agonist cis-4-aminocrotonic acid (CACA) did not influence either basal or K+-evoked 3H-NA release. These results point to a new type of GABA functional role through a different A-family receptor subtype, coupled with calcium influx in aminergic neuron terminals, modulating aminergic release.

1-Thiopsoralen, a new photobiologically active heteropsoralen. Photophysical, photochemical and computer aided studies.

1-Thiopsoralen (7H-thieno[3,2-g]benzofuran-7-one) 1, a lead compound of a series of heteropsoralens, was investigated. The electronic transitions involved were studied. Fluorescence quantum yield is very low, while laser flash photolysis showed that the triplet state is practically the sole transient of 1. Fluorescence quantum yield (phi F) and triplet lifetime (tau F) as well as triplet quantum yield (phi T) and lifetime (tau T) were determined. The production of singlet oxygen was also evaluated by photophysical measurements. Photophysical data suggest that DNA photobinding of 1, owing to short fluorescence lifetime value and high triplet quantum yield, occurs likely through triplet mechanism. Interactions between 1 and DNA were studied both in the ground and the excited state. In the ground state 1 undergoes intercalation inside duplex DNA. This fact is also supported by molecular modeling studies. By UVA-light activation 1 photobinds covalently to DNA forming mono and diadducts. The furan side 1-thymine monoadduct, isolated from DNA photomodified by thiopsoralen, shows a cis-syn stereochemistry, in agreement with quantum mechanics studies. Compound 1 photobinds also with linolenic acid, component of lecithins, giving a C4-cycloaddition, and supporting that this compound also induces photolesions at the level of cell membrane, like psoralen. Compound 1 exhibits strong skin-phototoxicity.

Subcapsular renal spread of a pancreatic pseudocyst.

In pancreatitis, the fluid collection may extend to unusual sites and organs and form a pseudocyst. We present US and CT findings of a pancreatic tail pseudocyst extending into the subcapsular space of the left kidney.

Age-related changes in rat brain monoamines release: peculiarity of dopamine release.

Our aim has been to investigate the ability of the rat brain to retain its level of neurotransmitter release over life. We have investigated the neurotransmitter release from the rat brain synaptosomes prelabeled with 3H-DA, 3H-NA, or 3H-5HT, and perfused with Krebs-Ringer medium alone (basal release) or containing a high K+, calcium ionophore, tyramine or amphetamine (evoked release). Brain areas have been dissected of animals 45 days and 4, 6, and 11 months old. The results have shown a gradual reduction of the 3H-NA release evoked by a high K+ from 45 days to 6 months, which is stabilized until 11 months of age. The reduction rate has been relatively different from the brain areas investigated (36% for the frontal cortex and 26% for the hippocampus and cerebellar cortex). A similar reduction has been seen with 3H-5HT released from synaptosomes of the frontal cortex, hippocampus, and striatum. Surprisingly, the 3H-DA release that was evoked by high K+ was greater in rats 11 months old than in younger rats; this effect has been seen in synaptosomes from the caudate and the frontal cortex. The calcium ionophore A23187 has shown a releasing picture similar to a high K+. When we analyzed a nonexocitotic, but probably carrier mediated, release (evoked by tyramine or amphetamine), there was reduced release of all of the above neurotransmitters from 45 days to 11 months of age. We presume that there have been adaptive changes in neurotransmitter evoked release due to changes in Ca++ utilization, as inferred from the results from calcium ionophore experiments and carrier performance.(ABSTRACT TRUNCATED AT 250 WORDS)

5HT2-receptors and serotonin release: their role in human platelet aggregation.

Involvement of 5HT2 receptors in human platelet aggregation was assessed by studying the effect of ADP, epinephrine and thrombin on 3H-5HT release from platelets. The release experiments were made with a perfusion method to preserve any compound, released or formed by platelet, from interacting with platelet itself. In these conditions, aggregation does not occur, as confirmed by Scanning Electron Microscopy. These release experiments showed that the platelet activation by such agents is coupled with 5-HT release. The aggregation experiments, made on different aliquots of the same platelet-rich plasma (PRP), showed that the released 5-HT, interacting with its own receptors on platelet activated surface, determines aggregation. In fact, although it is known that 5-HT added to PRP was only able to induce a moderate platelet aggregation, the 5-HT2 antagonist ketanserin counteracted the aggregation induced by ADP, epinephrine and thrombin. These results suggest that a 5HT2 antagonist could be therapeutically important in those pathological states in which serotonin, released by activated platelets, may increase aggregation.