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We report here on the use of the photoacoustic technique for the determination of low concentrations of total iron in corn meal samples. The determination of this element in food is of considerable interest because several foods are currently enriched with it at proper levels in order to increase the resistance of people, after consumation, to several diseases, such as anemia. The proposed technique is based on an open photoacoustic cell configuration in conjunction with a suitable colorimetric method. We applied it to a measurement of the total iron concentration in corn meal samples. The results agree very well with those obtained using a conventional spectrophotometric method, showing the possibilities of new experimental methodologies based on photothermal methods to perform this kind of study, with the advantage of a higher sensitivity and increment of the range of appreciable absorbance.

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Utilizaram-se 10 cäes neonatos (cinco machos e cinco fêmeas), obtidos a partir de cinco ninhadas (um casal de cada) com o objetivo de estabelecer o perfil ecodopplercardiográfico normal durante a fase neonatal (de um até 30 dias). Por meio do Doppler pulsado foram mensurados os picos de velocidade dos fluxos sangüíneos através das valvas mitral, tricúspide, aórtica e pulmonar. Observou-se correlaçäo positiva de todas as mensuraçöes com o peso corporal e a idade dos neonatos de ambos os sexos. Näo houve diferenças significativas no padräo de velocidade dos fluxos sangüíneos estudados entre machos e fêmeas durante a fase neonatal

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Ten healthy puppies (five males and five females) were used to establish the regular echodopplercardiography profile during the neonatal period (from one to 30 days) utilizing Doppler (pulsed-wave and color flow). Mitral, tricuspid, aortic and pulmonary blood flows were measured. Positive correlations of all the measures, with body weight and age of the puppies for both sexes were observed. No differences in the cardiac development between male and female during the neonatal phase were observed.

Utilizaram-se 10 cães neonatos (cinco machos e cinco fêmeas), obtidos a partir de cinco ninhadas (um casal de cada) com o objetivo de estabelecer o perfil ecodopplercardiográfico normal durante a fase neonatal (de um até 30 dias). Por meio do Doppler pulsado foram mensurados os picos de velocidade dos fluxos sangüíneos através das valvas mitral, tricúspide, aórtica e pulmonar. Observou-se correlação positiva de todas as mensurações com o peso corporal e a idade dos neonatos de ambos os sexos. Não houve diferenças significativas no padrão de velocidade dos fluxos sangüíneos estudados entre machos e fêmeas durante a fase neonatal.

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To the best of our knowledge, there is no simple way to induce neural networks to shift from waking mode into sleeping mode. Our best guess is that a whole group of neurons would be involved and that the process would develop in a period of time and a sequence which are mostly unknown. The quasi-total sensory deprivation elicits a new behavioral state called somnolence. Auditory stimulation as well as total auditory deprivation alter sleep architecture. Auditory units exhibiting firing shifts on passing to sleep (augmenting or diminishing) are postulated to be locked to sleep-related networks. Those ( approximately 50%) that did not change during sleep are postulated to continue informing the brain as in wakefulness. A rhythmic functional plasticity of involved networks is postulated. A number of auditory and visual cells have demonstrated a firing phase locking to the hippocampal theta rhythm. This phase locking occurs both during wakefulness and sleep phases. The theta rhythm may act as an organizer of sensory information in visual and auditory systems, in all behavioral states adding a temporal dimension to the sensory processing. Sensory information from the environment and body continuously modulates the central nervous system activity, over which sleep phenomenology must develop. It also produces a basal tonus during wakefulness and sleep, determining changes in the networks that contribute to sleep development and maintenance and, eventually, it also leads to sleep interruption.

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A ten year-old male Poodle dog, weighing 3 kg, was referred to the Veterinary Hospital of UFMG due to nocturnal coughing, exercise intolerance, weakness and weight loss. Physical examination revealed pale mucous membranes, prolonged capillary refill time, holosystolic regurgitant murmur at left apex and signs of congestive heart failure. M-mode, two-dimensional, and Doppler echocardiography revealed mitral chronic valvular disease

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Sleep-related changes-including modification in sensory processing-that influence brain and body functions, occur during both slow wave and paradoxical sleep. Our aim was to investigate how cortical auditory neurons behave during the sleep/waking cycle, and to study cell firing patterns in relation to the processing of auditory information without the interference of anesthetic drugs. We recorded single cells in the A region of the auditory cortex in restrained, chronically-implanted guinea pigs, and compared their evoked and spontaneous activity during sleep stages and quiet wakefulness. A new classification of the unit's responses to simple sound during wakefulness is presented. Moreover, a number of the neurons in the primary auditory cortex exhibited significant quantitative changes in their evoked or spontaneous firing rates. These changes could be correlated to sleep stages or wakefulness in 42.2% to 58.3% of the sampled neurons. A similar population did not show behavioral related changes in firing rates. Our results indicate that the responsiveness of the auditory system during sleep may be considered partially preserved. An important result was that spontaneous and evoked activity may vary in opposite directions, i.e. , the evoked activity could increase while the spontaneous activity decrease or vice versa. Then, a general question was proposed: is the increased spontaneous activity in the auditory cortex, particularly during PS, related to auditory hypnic 'images'? The studied cortical auditory neurons exhibit changes in their firing rates in correlation to stages of sleep and wakefulness. This is consistent with the hypothesis that a general shift in the neuronal networks involved in sensory processing occurs during sleep.

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A ten year-old male Poodle dog, weighing 3kg, was referred to the Veterinary Hospital of UFMG due to nocturnal coughing, exercise intolerance, weakness and weight loss. Physical examination revealed pale mucous membranes, prolonged capillary refill time, holosystolic regurgitant murmur at left apex and signs of congestive heart failure. M-mode, two-dimensional, and Doppler echocardiography revealed mitral chronic valvular disease

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The coarctation of the aorta is an uncommon pathology which has a high mortality rate during pregnancy; a very thorough antenatal control must be performed due to the serious complications that may cause death. It is important to eliminate any congenital malformations related to this pathology, such as aneurysms of the Willis polygon, Ductus Persistent or ventricular intercommunication; arterial pressure must be strictly controlled using antihypertensive drugs when needed with beta-blockers. The delivery route may be vaginal, C-section must be reserved only for obstetric reasons. We present a case studied in the Military Hospital, treated with antihypertensives, the fetus had intrauterine growth retardation and was delivered by C-section successfully.

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Peripatum cardiomyopathy is a rare disease, which appears as cardiac failure, at the end of pregnancy and puerperium without an apparent cause. The diagnosis is done clinically based in accepted criteria by Demakis, and it is confirmed by auxiliary tests. Treatment includes rest, digitalic and diuretic medications. Prognosis is bad when there is not symptomatic regression, with a high mortality soon after. The experience at Hospital Central Militar from 1967 to 1995, is presented. There were nine cases, two of which had died; and the presentation of the last case, is done herein.

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We report the case of a 62-year-old man with massive pulmonary embolism and severe hemodynamic impairment. Transthoracic Doppler echocardiography was fundamental in confirming the diagnosis by direct visualization of intra-atrial thrombus and signs of right chamber overload. It allowed prompt administration of thrombolytic drug and follow-up monitoring. Doppler echocardiography is a non-invasive, available technique and its early application should be considered in the evaluation of patients with suspected massive pulmonary embolism.

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After destruction of both cochleae, a significant enhancement of both paradoxical sleep and slow wave sleep together with decreased wakefulness, were observed for up to 45 days. The sleep augmentation consisted of an increment in the number of episodes of both slow wave and paradoxical sleep rather than in the duration of single episodes. The partial isolation provoked by deafness is postulated as explanation. We suggest that the suppression of one input to a complex set of networks related to the sleep-waking cycle, introduce an imbalance that leads to sleep enhancement.

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A incidência da fibrilação atrial aumenta com a idade, bem como as complicaçöes decorrentes dela própria e de seu tratamento, isto é, a anticoagulação. A principal complicação é a embolia cerebral, aumentada no idoso. Infelizamente, a incidência de complicaçöes hemorrágicas graves devido aos anticoagulantes está também aumentada e o ácido acetilsalicílico não se mostrou muito eficaz nessa faixa etária. A disfunção diastólica e as cardiopatias usualmente concomitantes tornam o idoso particularmente sensível às alteraçöes hemodinâmicas impostas pela fibrilação atrial, não sendo raras a dispnéia, as palpitaçöes constantes, a insufuciência cardíaca e as síncopes. Sendo assim, os autores propöem uma ênfase maior na tentativa de restauração e manutenção do ritmo sinusal nessa população, a fim de evitar a ocorrência de embolias sistêmicas sem o risco de hemorragias, além de proporcionar melhora mais eficaz da sintomatologia.

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The activity of 52 single auditory units in the central nucleus of the inferior colliculus (IC) was recorded along with cortical and hippocampal (CA1) electrograms and neck muscle electromyograms in behaving, head-restrained guinea pigs during paradoxical sleep (PS) and wakefulness. Sixteen (30%) of the IC auditory units showed positive correlation with the hippocampal theta (theta) rhythm: 8 (15%) were theta rhythmic with theta phase-locking (type 1), 8 (15%) showed only theta phase-locking with no rhythmicity (type 2), while 70% did not show any correlation to hippocampal theta rhythm (type 3). During wakefulness IC neurons (4 of 13) showed a higher synchrony with hippocampal theta when sound-stimulated at the unit's characteristic frequency. During PS all IC auditory neurons recorded presented some hippocampal theta correlation: 40% were rhythmic and phase-locked to the theta frequency and 60% were nonrhythmic maintaining the theta phase-locking. Shifts in the angle of phase-locking to the theta rhythm were observed during PS. It is suggested that the hippocampal theta rhythm may play the part of an internal clock, adding a temporal dimension to the processing of auditory sensory information.

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The effects of behavioral shifts on auditory lateral superior olive neurons were analyzed in guinea-pigs during the sleep-waking cycle with single unit extracellular recordings at the unit characteristic frequency and with low sound intensity. Shifts in the number of spikes in response to pure tones and in spontaneous firing proved to be closely related to waking, slow wave and paradoxical sleep. All of the recorded lateral superior olive (LSO) auditory neurons showed sleep-related firing shifts. Moreover, changes in the pattern of discharge over time were observed in 15% of the LSO cells on passing from waking to sleep. Sleep may determine either an increase or a decrease of the firing number in response to sound. The most important change observed in decreasing firing units was the near-absence of units responding to sound in the paradoxical sleep phase during the last 40 ms of the response. The waking cues for binaural detection, studied with our experimental paradigm, disappeared during slow wave sleep. We thus conclude that the binaural function of some lateral superior olive neurons (11.5%) was impaired during this sleep period in the present experimental conditions. Auditory efferent pathways are postulated to impinge on the auditory processing at LSO nucleus level during the sleep-waking cycle. Thus, auditory unitary activity appears to be dependent on both incoming information, and a CNS descending action closely related to the waking and sleep periods. Functional interactions between pontine sleep-related groups of neurons and auditory system units are suggested.

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The body generates many physiological sounds. One of the most prominent is that produced by the blood flowing inside the vessels with each heart beat. On the other hand, the cochlea is a very sensitive receptor with a low threshold. Given the anatomical close proximity of the carotid artery and other vessels to the inner ear, the possibility of its being stimulated is very high. Cochlear nucleus spontaneous as well sound-responding auditory units were studied. A close relationship between the heart beat, that is the blood flow, and the cochlear nucleus firing was demonstrated, in anesthetized and awake guinea-pigs. Temporary mechanical interruption of the blood flow through the ipsilateral carotid artery abolished firing increments at the cochlear nucleus time-locked to the heart beat. We conclude that one component of the so called 'spontaneous' firing in the auditory system is actually evoked activity due to normal body-generated sounds or noises.

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The effects of waking and sleep on the response properties of auditory units in the ventral cochlear nucleus (CN) were explored by using extracellular recordings in chronic guinea-pigs. Significant increases and decreases in firing rate were detected in two neuronal groups, a) the "sound-responding" and b) the "spontaneous" (units that do not show responses to any acoustic stimuli controlled by the experimenter). The "spontaneous" may be considered as belonging to the auditory system because the corresponding units showed a suppression of their discharge when the receptor was destroyed. The auditory CN units were characterized by their PSTH in response to tones at their characteristic frequency and also by the changes in firing rate and probability of discharge evaluated during periods of waking, slow wave and paradoxical sleep. The CNS performs functions dependent on sensory inputs during wakefulness and sleep phases. By studying the auditory input at the level of the ventral CN with constant sound stimuli, it was shown that, in addition to the firing rate shifts, some units presented changes in the temporal probability of discharge, implying central actions on the corresponding neurons. The mean latency of the responses, however, did not show significant changes throughout the sleep-waking cycle. The auditory efferent pathways are postulated to modulate the auditory input at CN level during different animal states. The probability of firing and the changes in the temporal pattern, as shown by the PSTH, are thus dependent on both the auditory input and the functional brain state related to the sleep-waking cycle.

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Horseradish peroxidase placed into the ventral mesencephalic periaqueductal gray (PAG) and in the lateral superior olivary complex region demonstrated indirect paths towards the cochlear nucleus (CN). Because no direct connections could be observed, a pathway throughout the auditory efferent system was proposed. The results suggest three possibilities: 1) The PAG is connected to the lateral superior peri-olivary complex synapsing with known efferent fibers that reach the CN; 2) Neurons located at the dorsal PAG were demonstrated to be connected to the inferior colliculus (IC). The possibility of synapses with known neurons that run from IC to the CN is postulated; 3) Neurons in the trapezoid body, which are partially associated with a system that communicates with the CN, are also connected to and from the PAG. The present results anatomically support an extracellular study (1) describing PAG actions on CN units.

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Horseradish peroxidase placed into the ventral mesencephalic periaqueductal gray (PAG) and in the lateral superior olivary complex region demonstrated indirect paths towards the cochlear nucleus (CN). Because no direct connections could be observed, a pathway throughout the auditory efferent system was proposed. The results suggest three possibilities: 1) The PAG is connected to the lateral superior peri-olivary complex synapsing with known efferent fibers that reach the CN; 2) Neurons located at the dorsal PAG were demonstrated to be connected to the inferior colliculus (IC). The possibility of synapses with known neurons that run from IC to the CN is postulated; 3) Neurons in the trapezoid body, which are partially associated with a system that communicates with the CN, are also connected to and from the PAG. The present results anatomically support an extracellular study (1) describing PAG actions on CN units.

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Horseradish peroxidase placed into the ventral mesencephalic periaqueductal gray (PAG) and in the lateral superior olivary complex region demonstrated indirect paths towards the cochlear nucleus (CN). Because no direct connections could be observed, a pathway throughout the auditory efferent system was proposed. The results suggest three possibilities: 1) The PAG is connected to the lateral superior peri-olivary complex synapsing with known efferent fibers that reach the CN; 2) Neurons located at the dorsal PAG were demonstrated to be connected to the inferior colliculus (IC). The possibility of synapses with known neurons that run from IC to the CN is postulated; 3) Neurons in the trapezoid body, which are partially associated with a system that communicates with the CN, are also connected to and from the PAG. The present results anatomically support an extracellular study (1) describing PAG actions on CN units.