Ultrasound-assisted encapsulation of curcumin and fisetin into Saccharomyces cerevisiae cells: a multistage batch process protocol.

Some of the challenges of yeast encapsulation protocols are low phytochemical internalization rates and limited intracellular compartments of yeasts. This study uses an ultrasound-assisted batch encapsulation (UABE) protocol to optimize the encapsulation of curcumin and fisetin by recovering nonencapsulated biomaterial and further incorporating it into nonloaded yeasts in three encapsulation stages (1ES, 2ES and 3ES). The effect of selected acoustic energies (166·7 and 333·3 W l-1 ) on the encapsulation efficiency (EE), yield (EY) and antioxidant activity retention were evaluated, and then, compared with a control process (without ultrasound treatment). Compared to the control, enhanced EEs were achieved for both curcumin (10·9% control to 58·5% UABE) and fisetin (18·6% control to 76·6% UABE) after 3ES and the use of 333·3 W l-1 . Similarly, the yeast maximum loading capacity was improved from 6·6 to 13·4 mg g-1 for curcumin and from 11·1 to 26·4 mg g-1 for fisetin after UABE protocol. The antioxidant activity of produced biocapsules was positively correlated with the bioactive-loaded content of yeasts when ultrasound treatment was applied. Overall, results from this study provide valuable information regarding UABE processes, and moreover, bring new and creative perspectives for ultrasound technology in the food industry.

Sensitivity to pain expectations: A Bayesian model of individual differences.

The thoughts and feelings people have about pain (referred to as 'pain expectations') are known to alter the perception of pain. However little is known about the cognitive processes that underpin pain expectations, or what drives the differing effect that pain expectations have between individuals. This paper details the testing of a model of pain perception which formalises the response to pain in terms of a Bayesian prior-to-posterior updating process. Using data acquired from a short and deception-free predictive cue task, it was found that this Bayesian model predicted ratings of pain better than other, simpler models. At the group level, the results confirmed two core predictions of predictive coding; that expectation alters perception, and that increased uncertainty in the expectation reduces its impact on perception. The addition of parameters relating to trait differences in pain expectation improved the fit of the model, suggesting that such traits play a significant role in perception above and beyond the influence of expectations triggered by predictive cues. When the model parameters were allowed to vary by participant, the model's fit improved further. This final model produced a characterisation of each individual's sensitivity to pain expectations. This model is relevant for the understanding of the cognitive basis of pain expectations and could potentially act as a useful tool for guiding patient stratification and clinical experimentation.

Neural basis of auditory expectation within temporal cortex.

Predictive coding frameworks of perception propose that neural networks form predictions of expected input and generate prediction errors when the external input does not match expectation. We therefore investigated the processing of unexpected sounds and silence in the auditory cortex using fMRI. Unexpected sounds, when compared to expected sounds, evoked greater activation in large areas of the left temporal and insular cortices. Additionally the left middle temporal gyrus exhibited greater activation to unexpected events in general, whether sounds or silence, when compared to the corresponding expected events. These findings support predictive coding models of perception, which suggest that regions of the temporal cortex function to integrate sensory information with predictive signals during auditory perception.

Adults with late diagnosed PKU and severe challenging behaviour: a randomised placebo-controlled trial of a phenylalanine-restricted diet.

BACKGROUND: Although early diagnosis and treatment in phenylketonuria (PKU) leads to excellent outcomes, a population of adults born before the introduction of newborn screening exists. They can have severe intellectual disabilities and behavioural problems, and are often dependent on full-time carers. Anecdotal evidence suggests that a diet that lowers blood phenylalanine concentration can have significant benefits upon behaviour. METHODS: A prospective double-blind randomised placebo-controlled crossover trial of phenylalanine-restricted diet was performed in a group of 34 adults (aged 21-61 years, median 49) with late diagnosed PKU with severe challenging behaviour. RESULTS: Only 17 completed the 60 week study: seven withdrew before the end of the baseline period; five withdrew during the first diet period; five withdrew during the second diet period (after moving into placebo phase). The mean (SD) blood phenylalanine was 1570 (222) micromol/l during baseline, 553(158) mumol/l during the active phase and 1444 (255) micromol/l during the placebo phase. In the 22 participants exposed to both active and placebo phases, no differences were demonstrated in behaviour assessed by the Aberrant Behavior Checklist and Vineland Adaptive Behavior Scales, behaviour diaries or on video analysis of direct observations. However, 76% of carers' comments were scored as positive during the active phase, compared with 54% during the placebo phase (chi(2) = 38.06, p<0.001). CONCLUSIONS: There are significant challenges in studying people with intellectual disabilities and considerable difficulties in instituting phenylalanine-restricted diet in this population. However, if attempted, there are potential benefits to quality of life for the individuals with PKU and their carers.

Intraoperative decrease in pulse oximeter readings following injection of isosulfan blue.

PURPOSE: Sentinel lymph node mapping, involving injection of isosulfan blue dye around a tumour, is beginning to be used in patients with carcinoma of the breast. Absorption of the dye into the circulation may interfere with pulse oximetry, causing falsely low readings. This report describes changes in pulse oximeter readings following injection of isosulfan blue for sentinel lymph node mapping in a patient with carcinoma of the breast. CLINICAL FEATURES: An 83-yr-old female patient underwent sentinel node biopsy of the axilla followed by partial mastectomy for carcinoma of the left breast. Isosulfan blue was injected in the area of the tumour in the left breast. The SpO2 began to decrease 15 min after dye injection, reaching a nadir of 89-90% 30 min after injection. Arterial blood gas analysis showed normal arterial partial pressure of oxygen. Pulse oximeter readings did not return to normal until more than six hours after dye injection. CONCLUSION: Review of the literature reveals a small number of case reports of similar occurrences of low pulse oximeter readings following injection of isosulfan blue or patent blue dye for lymphatic mapping. Data from these reports and the case described here suggest that the latency, magnitude and duration of effect on pulse oximeter readings following injection of these dyes is highly variable. It is important to rule out other causes of low pulse oximeter readings when this effect occurs; normal oxygenation can be verified with arterial blood gas analysis. Co-oximetry can be done to rule out methemoglobinemia as a cause of decreased SpO2.

Reevaluation of the balloon in gastrointestinal manometry.

Although the flow-through catheter (FTC) system has been useful and satisfactorily accurate for gastrointestinal manometry, we hypothesized that a cylindrical, liquid-filled balloon would also accurately reflect stress imposed by a sphincter. Latex balloons were fitted over the side ports of a closed-end catheter. The responses of the balloon and FTC system were compared in a cylindrical chamber commonly identified as a Starling resistor. Independent, constant-pressure sources were used to control both the inwardly directed "contact pressure" of the Starling resistor (Ps) and the intraluminal fluid pressure (P(lum)). The balloon transducers responded linearly and accurately (slope = 1) to changes in both Ps and P(lum) within the test range (0-200 mmHg, 0-26.7 kPa). When either P(lum) or Ps was held constant and the other changed, the balloon transducers always accurately measured the higher of the two pressures. Although the performance of the FTC system was improved after the Starling resistor was lubricated, the FTC system sometimes responded inaccurately to changes in Ps. The ability of the balloon transducers to measure the contractions of the lower esophageal sphincter and of the esophagus was demonstrated. We conclude that the balloon transducer can measure sphincter pressure accurately and suggest that, in certain circumstances, it might be advantageous relative to the FTC system.

The use of a low phenylalanine diet with amino acid supplement in the treatment of behavioural problems in a severely mentally retarded adult female with phenylketonuria.

If phenylketonuria is untreated in infancy, it causes irreversible brain damage. No dietary treatment can alter this brain damage. However, it has been shown that dietary treatment can reduce behaviour disturbances often associated with the condition. In this study, a subject's behaviour was monitored over 18 weeks while on a low phenylalanine diet. Results demonstrate a significant reduction in the level of her disturbed behaviour.

Projections from inspiratory neurons of the nucleus retroambigualis to phrenic motoneurons in the cat.

The connection between the inspiratory neurons of the nucleus retroambigualis and the phrenic motoneurons was examined using the techniques of antidromic mapping to discover collaterals and spike-triggered averaging to detect postsynaptic potentials. Axon collaterals within the region of the C5 phrenic nucleus were found for 17 of 26 (65%) inspiratory neurons and 6 of these 17 (35%) were shown to generate excitatory postsynaptic potentials in at least one phrenic motoneuron. It was concluded that these results demonstrate a strong connection for those inspiratory neurons of the nucleus retroambigualis with a collateral within the phrenic nucleus.

Temperature and metabolic responses to inhalation and bath rewarming protocols.

Rewarming of mildly hypothermic subjects was compared using three different techniques that have been suggested for use in field situations. Eight subjects were cooled for up to 1 h, on four occasions, in a filled whole-body water calorimeter controlled at 22 degrees C. Following cooling, rewarming was initiated by one of four procedures: inhalation of warmed and humidified air at 40 degrees C or 45 degrees C, immersion in 40 degrees C water, or spontaneously by shivering. Deep body temperature was recorded simultaneously at three different sites: rectal, esophageal, and auditory canal. Skin temperatures were recorded from four sites: chest, forearm, thigh, and calf. Results showed that rapid external rewarming in 40 degrees C water produced the quickest rate of rewarming and smallest magnitude and duration of afterdrop. Regardless of which rewarming protocol was followed, the esophageal site always showed the smallest afterdrop. Although there were no differences in the rewarming rates calculated for each of the three core temperature sites during inhalation and spontaneous rewarming, both auditory canal and esophageal sites rose significantly quicker than rectal during the rapid rewarming in 40 degrees C water. Inhalation rewarming led to a depressed metabolic rate, compared to spontaneous rewarming, which was not compensated by heat provided through the respiratory tract. It was concluded that for mildly hypothermic subjects, rapid rewarming in 40 degree C water was the most efficient procedure and that esophageal temperature--the closest approximation of aortic blood or cardiac temperature--is the most sensitive to change during rewarming by any procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Projections from upper cervical inspiratory neurons to thoracic and lumbar expiratory motor nuclei in the cat.

Previous studies have demonstrated the existence of axonal projections from propriospinal respiratory neurons in the rostral cervical cord of the cat (upper cervical inspiratory neurons) to the vicinity of the phrenic and rostral thoracic inspiratory (external) intercostal motoneurons. However, no synaptic targets of the upper cervical inspiratory neurons have been identified. This study investigated the axonal projections to the caudal thoracic and upper lumbar cord and the possible existence of inhibitory connections to the expiratory intercostal and abdominal motoneurons. The connections from upper cervical inspiratory neurons to expiratory motoneurons in the lower thoracic cord were examined using the methods of antidromic mapping and the spike-triggered averaging of intracellular potentials. Of the 70 upper cervical inspiratory neurons examined, only four (5.7%) could not be antidromically activated from the T9 segment of the spinal cord. The axons of 66 upper cervical inspiratory antidromic activation at less than 5 microV, and the presence of collaterals was confirmed by antidromic mapping in 30 cases (49.2%). Of 21 axons tested for lumbar projections, 13 (61.9%) projected as far as T12, seven (33.3%) as far as L1, three (14.3%) as far as L2, and one (4.8%) was antidromically activated from L3. Spike-triggered averaging of the synaptic potentials recorded intracellularly from expiratory intercostal motoneurons in T9 and T10 spinal segments was done for 27 upper cervical inspiratory neurons, 17 of these with 4 or more motoneurons, for a total of 111 expiratory motoneurons. In 16 cases the motoneurons were injected with Cl- to reverse IPSPs and the spike-triggered averaging was repeated. No monosynaptic or disynaptic post-synaptic potentials were seen in any of the spike-triggered averages. We concluded that the upper cervical inspiratory neurons may provide inspiratory inhibition to expiratory motoneurons via a di- or oligosynaptic pathway involving segmental inhibitory interneurons and that either the spike-triggered averaging technique was not sensitive enough to detect the ipsilateral connections or the interneuron pathway was to the contralateral side of the spinal cord.

Intracellular recordings from upper cervical inspiratory neurons in the cat.

Intracellular recordings were made from propriospinal, inspiratory neurons, at the lateral edge of lamina VII in the upper cervical cord of the cat. The membrane potentials were found to fluctuate with the central respiratory rhythm, as determined from a recording of the phrenic nerve discharge. Excitatory postsynaptic potentials occurred during the inspiratory phase, and inhibitory postsynaptic potentials were shown to occur in the expiratory phase by injecting chloride to reverse them. These recordings are the first demonstration that the upper cervical inspiratory neurons receive both excitation during inspiration and inhibition during expiration.

Excitation of upper cervical inspiratory neurons by inspiratory neurons of the nucleus retroambigualis in the cat.

The experiments reported here examined inputs from inspiratory neurons of the nucleus retroambigualis to upper cervical inspiratory neurons. Antidromic mapping in contralateral C1 demonstrated the existence of axon collaterals for 9 of 19 nucleus retroambigualis axons tested (47%). Forty nucleus retroambigualis neurons were tested with antidromic mapping for a projection to the ipsilateral C1 segment; 9/40 (22%) had an ipsilateral axon (8 of these also projected contralaterally), and 2/40 (5%) had an axon collateral in ipsilateral C1. Cross-correlation histograms suggested monosynaptic excitation of an upper cervical inspiratory neuron by a contralateral nucleus retroambigualis neuron in 4/69 cases (6%) and common input to the pair in 2/69 cases (3%). Six of the 69 cross-correlograms were computed during antidromic activation of the nucleus retroambigualis neuron, and one of these six demonstrated direct excitation of the upper cervical inspiratory neuron by the retroambigualis neuron. We concluded that at least some upper cervical inspiratory neurons receive monosynaptic excitation from the contralateral, and possibly the ipsilateral, nucleus retroambigualis inspiratory neurons. These results, together with those published elsewhere for inputs from inspiratory neurons in the contralateral ventrolateral nucleus tractus solitarius, suggest that the rhythmic, inspiratory firing pattern of the upper cervical inspiratory neurons is due to excitatory inputs from these two inspiratory bulbospinal neuron populations.

Excitation of upper cervical inspiratory neurons by inspiratory neurons of the nucleus tractus solitarius in the cat.

Experiments were conducted to investigate the connection from inspiratory neurons in the ventrolateral region of the nucleus tractus solitarius to the inspiratory neurons in the contralateral upper cervical (C1-C2) spinal cord. Microstimulation within the region usually produced long-latency (10 to 30 ms) synaptic activation of the upper cervical inspiratory neurons. Antidromic mapping of axons of the ventrolateral nucleus tractus solitarius in C1 demonstrated the existence of collateral arbors in the region of the upper cervical inspiratory neurons (7 of 15). Cross-correlation histograms showed the existence of short-term synchronization of firing for 12 of 74 pairs of ventrolateral nucleus tractus solitarius and upper cervical inspiratory neurons. Cross-correlation combined with antidromic activation showed that the short-term synchronization was due to a direct connection in two cases and a common input in one case. It was concluded that at least some ventrolateral nucleus tractus solitarius inspiratory neurons may directly excite upper cervical inspiratory neurons, probably via monosynaptic connections. Both groups of neurons may also share common inputs.

Bath rewarming from immersion hypothermia.

Trunk-only bath rewarming has often been recommended over whole-body bath rewarming as a method for the treatment of immersion hypothermia. At present, no report of a direct comparison of the relative merits of these techniques has been made. Authorities in favor of trunk-only bath rewarming base their proposal on the assumption that core temperature afterdrop would be minimized by preventing peripheral vasodilation when the subject's limbs are not immersed in the rewarming bath. In the present study, trunk-only and whole-body bath rewarming are compared by rewarming eight mildly hypothermic male subjects twice, once via each technique. It was concluded that trunk-only rewarming is not superior to whole-body bath rewarming as a therapy for mild immersion hypothermia, based on the findings that no significant differences existed between the two techniques, either in size or duration of core temperature afterdrop, or in rate of rewarming.