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Biomedical subjects

M Peres

Publications and source records attributed to M Peres.

13 recordsLinked to original sources
PubMed2001

Notification of Papanicolaou smear results: a survey of women's experiences and preferred means of notification.

In a population of Australian women attending a colposcopy clinic, we aimed to establish the method by which they were notified of their Pap smear result, who notified them of their result, and if given the choice, how they would prefer to be notified. Of women attending a colposcopy clinic between October 1998 and June 1999, 59.7% participated in the survey. There was a final sample of 210 women after exclusion of questionnaires with missing data. The doctor most often notified women of their Pap smear result (81.7%). The usual methods of notification were by a follow-up appointment (43.1%), by a telephone call (35.8%) or with a letter (13.8%); 42% of women preferred to be notified with a mailed copy of the report and explanation of follow-up; 29.6% preferred to be telephoned with the result, and 11.3% would prefer a follow-up appointment. Women preferred methods of notification which were initiated by the doctor. Women have varying preferences, which commonly differ from the current services provided by both GPs and colposcopy clinic. To overcome this, women could be asked to nominate their preferred method of notification when completing the cervical smear request form.

Adolescent↗
PubMed2001

The Lennart Nilsson Award.

This article takes a brief look at the photography of Lennart Nilsson as well as the history of, and the formation of a foundation to raise monies for the establishment of an award in his name. Subsequently, a board and an international nominating committee evolved to select individuals to receive the award. Honorees are chosen based on the merits of their efforts in scientific imagery that, like the photography of Nilsson, reveal the unseen in the natural world. Finally, this article discusses the work of the latest two recipients of the award and invites readers to participate in the nomination process.

Archaeology↗
PubMed1998

Effects of prolonged exercise on brain ammonia and amino acids.

The aim of this study was to investigate if enhanced peripheral ammonia production during exhaustive exercise increases ammonia detoxication in brain mediated by glutamine synthesis, and subsequently influences glutamate and gamma-aminobutyric acid (GABA) levels. This neurotransmitter production is related to the metabolism of glutamine. A group of rats was trained for 6 weeks by treadmill running (TR). They were compared to a group of untrained rats (UN). At the end of training, half of TR and UN rats were submitted to one session of treadmill running until exhaustion (288+/-12 min and 62+/-5 min in TR and UN group, respectively). At exhaustion, running and control rats were sacrificed in order to collect blood and to take samples of the following brain structures: cortex, striatum and cerebellum. Treadmill running until exhaustion induced an increase in blood ammonia by 140% without significant differences between TR and UN groups. Brain ammonia increased in both groups. However, TR group exhibited values 50% higher than those observed in UN group. Brain glutamine was increased at exhaustion in all groups of running rats by 30-75% of basal value whereas the glutamate only decreased in TR rats which were able to run for a longer time. In this group, the GABA level decreased in striatum. These data confirm that enhanced brain ammonia level during exercise stimulates glutamine synthesis as a mechanism of detoxication. After several hours of running, a reduction in brain glutamate levels was observed in all brain structures in trained rats but only in the striatum in untrained animals. The reduced availability of this GABA precursor decreases GABA levels only in the striatum of TR group by 45% of the resting value. These results suggest a relation between cerebral changes in neurotransmitters and excitatory amino acids, such as glutamate and GABA, and central fatigue.

Ammonia↗
PubMed1994

Effects of kainate-induced seizures on cerebral metabolism: a combined 1H and 31P NMR study in rat.

The cerebral metabolic changes elicited by kainate-induced seizures in the rat were investigated by in vivo combined NMR spectroscopy of 31P and 1H. Systemic injection of kainate induced no significant changes in cerebral ATP or PCr levels during up to 90 min of continuous, generalised seizures, and the cerebral 31P spectra showed only a transient mild cerebral acidosis 30 min after kainate administration. In parallel with the changes in intracellular cerebral pH, the 1H spectra showed a significant increase in lactate, which remained elevated throughout the seizures. These findings indicate that oxidative metabolism does not completely match the increased glycolysis during seizures though the energy homeostasis is maintained. This suggests that oxidative metabolism has a limited capacity to satisfy the brain's energy needs during the kainate-induced seizures, but that the different pathways of energy production in the brain cells can overcome this limitation. Thus the brain damage associated with this experimental model of epilepsy is not due to extended major failure of the energy supply.

Acidosis↗
PubMed1992

In vivo identification and monitoring of changes in rat brain glucose by two-dimensional shift-correlated 1H NMR spectroscopy.

Intracerebral glucose resonance was directly detected and resolved in vivo by two-dimensional shift-correlated (COSY) 1H NMR spectroscopy in anesthetized rats (n = 4). The relative changes in brain glucose concentration were measured by volume integration of the alpha-D-glucose cross peak in the 2D COSY spectra. This report demonstrates the possibility of monitoring the variations in cerebral glucose following iv injection of glucose.

Animals↗
PubMed1990

2D COSY 1H NMR: a new tool for studying in situ brain metabolism in the living animal.

2D COSY 1H NMR with surface coil has been used to resolve and assign cerebral metabolites which had previously been detected but could not be resolved or assigned in situ in the living animal by conventional 1D 1H NMR. A wide range of cerebral metabolites, including alanine, N-acetyl aspartate, aspartate, choline derivatives, creatine/phosphocreatine pool, GABA, glucose, glutamate/glutamine pool, inositol, lactate and taurine were simultaneously resolved and assigned in situ in the whole animal using the 2D COSY correlation graphs. Global irreversible ischemia caused the appearance and the disappearance of cross-peaks in the 2D COSY 1H NMR map, corresponding to increases in alanine, GABA and lactate and glucose depletion.

Animals↗
PubMed1988

In vivo 31P nuclear magnetic resonance (NMR) study of cerebral metabolism during histotoxic hypoxia in mice.

The alterations of cerebral energetic metabolism and intracellular brain pH that occur during histotoxic hypoxia were estimated in mice by in vivo 31P nuclear magnetic resonance (NMR) spectrometry. The brain spectra obtained by means of chronically implanted surface coils connected to a special designed probe were recorded sequentially and continuously before, during, and after histotoxic hypoxia induced by an injection of potassium cyanide. The levels of PCr, ATP, inorganic phosphate, and intracellular pH estimated from the records of the 31P cerebral spectra and the cerebral cortical activity allow noninvasive monitoring of both the energetic metabolism and the functional state of the brain in unanesthetized animals. The time courses of these different parameters are largely the same as those obtained previously by invasive methods, however, the simultaneous and continuous monitoring performed in this study exhibits several unexpected dissociations between, respectively, onset of coma, decrease in PCr level and intracellular pHi, and recovery of normal levels of PCr and intracellular pH. These dissociations indicate that tissue acidosis plays a minor role in the changes in PCr levels, compared with ATP, and they confirm that the thresholds of oxidative metabolism required for functional tissue activity and a normal rate of ATP are clearly different.

Animals↗
PubMed1975

[Sclerodermoid porphyria cutanea tarda associated with cataract].

Two cases of Porphyria cutanea tarda with sclerodermoid changes associated with cataracta are studied. Far from being considered as an authentic scleroderma, the sclerodermoid aspect, very common in patients with Porphyria cutanea tarda, seems to represent one among the many residual alterations of the precocious cutaneous senescence, peculiar to these individuals hypersensitive to luminic radiations. The first patient had familial cases of cataracta. The second had no familial occurrence of it. The association of cataracta and Porphyria cutanea tarda, for the first time mentioned in the literature, would be one complication to be added to this very polymorphous syndrome.

Adult↗
PubMedDate not supplied

Two-dimensional 1H spectroscopic imaging for evaluating the local metabolic response to focal ischemia in the conscious rat.

Two-dimensional 1H spectroscopic imaging and magnetic resonance imaging were used to study focal ischemia induced by middle cerebral artery occlusion in rats. A water suppressing spin-echo sequence was used at 4.7 T. Phase encoding during the spin-echo delay (TE = 272 ms) yielded an 8 x 8 array of 35 microL voxels. The injured area of the brain had a higher lactate level and markedly lower N-acetyl aspartate, creatine and choline levels than did the non-ischemic regions. The spectroscopic imaging data clearly showed the localization of the infarct, which agreed well with both magnetic resonance imaging and the histological data obtained post-mortem. This study demonstrates the potential usefulness of combining magnetic resonance imaging and 1H spectroscopic imaging for studying animal models of stroke, and indicates the suitability of the technique for further pharmacological approaches.

Animals↗