Synthesis, solid-state characterization and solution studies of new phytate compounds with Cu(ii) and 1,10-phenanthroline: progress in the structural elucidation of phytate coordinating ability.

Within all the eukaryotic cells there is an important group of biomolecules that has been potentially related to signalling functions: myo-inositol phosphates (InsPs). In nature, the most abundant member of this family is the so called phytate (InsP6, L(12-)). The importance of the interaction of InsP6 with cations has been recognized during the last few years, and any attempt to know the function of this molecule in eukaryotic cells must include the fact that InsP6 will be strongly associated with simple inorganic or organic ammonium cations. In this work we expand on our earlier findings by studying the systems phen-phytate (phen = 1,10-phenanthroline) and Cu(ii)-phen-phytate. The structures of (Hphen)4(H8L)·7.5H2O and [Cu5(H7L)2(H2O)2(phen)5]·23H2O are presented. Solution studies of the binary and ternary systems were also performed by means of potentiometric titrations at 37.0 °C and 0.15 M ionic strength. The work was completed with a molecular modelling study. All this information is essential in the process of gaining reliable structural knowledge about the most important InsP6 species in the in vitro and in vivo experiments, and how these features modulate their probable biological functions.

Differential retinal origins of separate anatomical channels for pattern and motion vision in rabbit.

The most conspicuous feature of the rabbit retina is the visual streak that extends along the horizontal azimuth from the nasal margin to the temporal limit of the retina. We believe the streak processes movement vision and that the temporal region (area centralis) is responsible for pattern perception. Both anatomical and behavioural experiments were used to test this hypothesis. Behavioural measures of pattern vision in normal and chiasma-sectioned rabbits revealed both to have the same visual acuity. Using OKN as a measure of movement vision, normal rabbits showed both a directional and velocity-tuned response. The chiasma-sectioned rabbits, with only uncrossed fibre projections remaining, showed a total loss of movement detection. The injection of HRP into the vitreal chamber of one eye in normal rabbits revealed extensive uptake throughout the contralateral thalamus. In the ipsilateral thalamus, there was uptake solely from the ipsilateral retinal projection to a restricted wafer of the lateral geniculate nucleus (LGN). The chiasma cut rabbits showed a very different distribution of HRP in the thalamus. The uptake was restricted to a thin wafer of the LGN, with no contralateral uptake. Thus, the thalamic projections from the retinal area centralis were strictly segregated from the thalamic target areas for the visual streak without any overlap. These findings provide strong evidence for separate retinal origins with anatomically separate pathways for pattern and movement vision in the rabbit.

An animal model of hypnotic pain attenuation.

The tonic immobility state (TIS) in rabbit has great potential as an animal model of hypnosis in humans, due to the strong similarities between TIS and hypnosis. It is additionally the only mammalian model available for studying mechanisms of hypnosis. However, its ability to modulate pain perception has yet to be clearly determined. The present experiment examined the effect of nociceptive conditioning in normal, TIS and lidocaine-treated rabbits. This involved three separate phases. In phase one all animals were trained on a continuous performance test (CPT). In the second phase animals were given Pavlovian conditioning to an auditory CS paired with a nociceptive US. In the third phase the animals are given a sensory recognition test. The control group were conditioned during a normal state, the TIS group were conditioned during TIS, the pain control animals were conditioned after lidocaine injection in the skin area stimulated by the nociceptive US. All animals in the normal group showed the greatest amount of pain conditioning, with an average disruption time (dt) of 175s. Animals in the lidocaine group showed little signs of conditioning with an average dt of 16s. Animals conditioned during TIS had an average dt of 42s. These results show that TIS can modulate pain perception similar to animals that did not experience a pain CS. They additionally argue that tonic immobility can produce attenuation of pain perception similar to hypnosis in humans.

The role of sensory pathways in Pavlovian conditioning in rabbit.

In an earlier experiment we showed that selective attention plays a critical role in rabbit eye blink conditioning (Steele-Russell et al. in Exp Brain Res 173:587-602, 2006). The present experiments are concerned to examine the extent to which visual recognition processes are a separate component from the motor learning that is also involved in conditioning. This was achieved by midline section of the optic chiasma which disconnected the direct retinal projections via the brainstem to the cerebellar oculomotor control system. By comparing both normal and chiasma-sectioned rabbits it was possible to determine the dependence or independence of conditioning on the motor expression of the eye blink response during training. Both normal and chiasma-sectioned animals were tested using a multiple test battery to determine the effect of this redirection of the visual input pathways on conditioning. All animals were first tested for any impairment in visual capability following section of the optic chiasma. Despite the loss of 90% of retinal ganglion cell fibres, no visual impairment for either intensity or pattern vision was seen in the chiasma animals. Also no difference was seen in nictitating membrane (NM) conditioning to an auditory signal between normal and chiasma animals. Testing for motor learning to a visual signal, the chiasma rabbits showed a complete lack of any NM conditioning. However the sensory tests of visual conditioning showed that chiasma-sectioned animals had completely normal sensory recognition learning. These results show that NM Pavlovian conditioning involves anatomically separate and independent sensory recognition and motor output components of the learning.

Selective attention and Pavlovian conditioning.

The present results show that the common practice of using self-indexing conditioned stimuli (CSs) in research on Pavlovian conditioning is a major source of experimental bias. The typical stimulus used is either a light flash or a sound pulse in a light/sound-shielded chamber. Under these conditions the onset characteristics of the CS signal totally predominate over the durational characteristic, i.e. the pattern information. Thus a visual pattern presented as a CS in a dark chamber is confounded with a brightness change from darkness to light. In the first experiment, animals were conditioned with a brightness CS using a self-indexing signal paradigm. When tested for specificity of the conditioning, they showed complete transfer of learning to either a visual pattern or even an auditory CS. These findings indicated that the traditional conditioning paradigm is biased towards non-specific sensory learning. The second experiment showed that specific sensory conditioning is critically dependent on selective attention mechanisms. When the onset characteristics of the CS signal were de-emphasized by the use of equal energy background illumination in the intertribal interval (ITI) during conditioning, the animals were not able to feature extract either the onset or the durational component of the CS signal from the ITI background despite prolonged training. It was only by starting with conditioning that was initially anchored to the CS onset characteristics that a perceptual fade-in procedure would bias attention to feature extract the durational characteristics of the CS. Thus conditioning occurred only when the rabbit's attention was directed to detection of the gratings display without any associated changes in visual albedo. Perhaps the most important finding of the present experiments is that the use of self-indexing CS signals in Pavlovian conditioning inevitably introduces non-specific sensory processing involving multiple sensory input pathways in the conditioning. This inherent uncertainty of the sensory input pathways presents a problem for clarifying the role of sensory pathways in the neural mechanisms of NM conditioning. In addition, the use of self-indexing CSs inevitably leads to an underestimation of the role of forebrain mechanisms in Pavlovian conditioning.

Acute effects of neuroleptics on unmedicated schizophrenic patients and controls.

Acute administration of haloperidol (0.2 mg/kg) produced many more side effects in normal controls than in unmedicated schizophrenic patients. Prior to the neuroleptic challenge, both groups were on the peripheral monoamine oxidase inhibitor, debrisoquin, for at least 1 week, in order to enhance the relative contribution of CNS catecholamine metabolites to those measured in both plasma and urine. The patient group had higher plasma levels of methoxyhydroxyphenylglycol (MHPG) and homovanillic acid (HVA) and higher urinary MHPG output than controls, but there were no effects of haloperidol challenge, compared to placebo challenge. In both groups there were significant declines in plasma HVA levels from 8:30 AM to 12 NOON. These declines were unaffected by the haloperidol challenge. Explanations for the marked differences in behavioral effects of haloperidol on patients and controls include the possibility that dopamine receptor numbers were increased in the brains of the schizophrenic patients.

Desmoide de mama y syndrome de Gardner. / Desmoid breast tumor and Gardner's syndrome

Se presenta un caso de tumor desmoide de mama en una portadora de un sindrome de Gardner. Se senala lo excepcional de esta localizacion y se hace una breve revision sobre la enfermedad de Gardner

Lipoma del intestino delgado. A proposito de un nuevo caso. / Lipoma of small intestine. Apropos of a case

Se publica un nuevo caso de lipoma de intestino delgado, que se presento como una hemorragia digestiva. Se hace una revision del tema, sus caracteres clinicos y anatomo-patologicos

Hemorragias abdominales en el postoperatorio de duodenopancreatectomias cefalicas. A proposito de 2 observaciones sucesivas. / Abdominal hemorrhages in the postoperative period of duodenopancreatectomies. Apropos of 2 successive observations

Una de las complicaciones mas frecuentes de la duodenopancreatectomia es la hemorragia postoperatoria facilitada por la compleja diseccion anatomica, las multiples suturas y los trastornos de coagulacion provocados por la ictericia. Se presentan las observaciones muy similares correspondientes a dos pacientes de 43 y 39 anos, portadores de pequenos canceres periampulares (papila y uncus pancreatico). Ambos fueron operados despues de un mes de ictericia con trastornos de crasis que persistieron en el postoperatorio de la duodenopancreatectomia cefalica.Fueron reoperados por complicaciones hemorragicas, en uno de ellos peritoneal y en el otro peritoneal y gastrica. En este ultimo la formacion de un grueso coagulo intraluminal provoco la oclusion mecanica del estomago y el asa diverticular de yeyuno. Corregida la coagulacion y detenidas las hemorragias se practico en ambos la "toilette" peritoneal efectuando anastomosis yeyuno-yeyunales al pie de la gastrectomia. Uno de los pacientes constituyo una fistula gastrica entre la linea de sutura y una gastrotomia vertical realizada para evacuar los coagulos. La curacion se conseguio recien despues de numerosas reintervenciones.Ambos enfermos se encuentran bien actualment