Diazepam induced sleep spindle increase correlates with cognitive recovery in a child with epileptic encephalopathy.

BACKGROUND: Continuous spike and wave of sleep with encephalopathy (CSWS) is a rare and severe developmental electroclinical epileptic encephalopathy characterized by seizures, abundant sleep activated interictal epileptiform discharges, and cognitive regression or deceleration of expected cognitive growth. The cause of the cognitive symptoms is unknown, and efforts to link epileptiform activity to cognitive function have been unrevealing. Converging lines of evidence implicate thalamocortical circuits in these disorders. Sleep spindles are generated and propagated by the same thalamocortical circuits that can generate spikes and, in healthy sleep, support memory consolidation. As such, sleep spindle deficits may provide a physiologically relevant mechanistic biomarker for cognitive dysfunction in epileptic encephalopathies. CASE PRESENTATION: We describe the longitudinal course of a child with CSWS with initial cognitive regression followed by dramatic cognitive improvement after treatment. Using validated automated detection algorithms, we analyzed electroencephalograms for epileptiform discharges and sleep spindles alongside contemporaneous neuropsychological evaluations over the course of the patient's disease. We found that sleep spindles increased dramatically with high-dose diazepam treatment, corresponding with marked improvements in cognitive performance. We also found that the sleep spindle rate was anticorrelated to spike rate, consistent with a competitively shared underlying thalamocortical circuitry. CONCLUSIONS: Epileptic encephalopathies are challenging electroclinical syndromes characterized by combined seizures and a deceleration or regression in cognitive skills over childhood. This report identifies thalamocortical circuit dysfunction in a case of epileptic encephalopathy and motivates future investigations of sleep spindles as a biomarker of cognitive function and a potential therapeutic target in this challenging disease.

Comparison of transcutaneous oxygen tension with arterial oxygen tension in newborn infants with severe respiratory illnesses.

Transcutaneous oxygen tension (tcPO2), measured by two skin electrodes of different design, and arterial oxygen tension (PaO2), measured by an intravascular oxygen electrode, were continuously recorded for periods of six hours in 15 newborn infants with serious respiratory illnesses. Ten of the infants needed mechanical ventilation and three needed continuous positive airway pressure. One skin electrode had three microcathodes surrounded by a heated ring-shaped anode, and the other had a large heated cathode. The temperature of both electrodes was set at 44 degrees C and they were calibrated in vitro. The tcPO2 recorded by the electrode with the microcathodes was found to estimate PaO2 reasonably accurately for the whole six-hour duration of the study. The tcPO2 recorded by the electrode with the large cathode gave a similar estimate of PaO2 for three hours, but then tcPO2 often fell relative to PaO2. This fall was probably caused by skin changes at the electrode site. For a variety of reasons, our results suggest that measurement of tcPO2 is unlikely to replace continuous intravascular measurement of PaO2 in infants with severe respiratory illnesses.

Palliative home care in a rural setting: reflections on selective interactions.

Despite the fact that terminally ill patients are approaching the end-stage of their lives, the need for information and continuing involvement in their own care remains paramount and does not necessarily diminish as their dependency increases. This paper supports the view that nurses working in the area of rural palliative care are in an optimum position to establish the kind of relationship with patients and informal carers that augments a sense of involvement, self determination, equity and trust. This is of particular significance to rural palliative care where service provision may be under-resourced and where domiciliary nurses are often the key provider for continuing care and support.

Client education experiences in professional nursing practice--a phenomenological perspective.

This paper reports a small-scale phenomenological study of registered nurses' experiences with their client education role. Its purpose was to investigate phenomena associated with actual experiences as they were encountered by participants. A review of the literature provides an overview of client education in terms of its definition and utility, and draws attention to the notion of compliance and the influence of power in health provider-client relationships. Phenomenology offers an appropriate methodological framework for investigating symbolic experiences, and three central concepts are yielded from aggregate data in the form of confirming experiences, disconfirming experiences and educational processes. Findings indicate that nurses' value the uniqueness of the client and, where possible, tend to initiate educational processes that actually empower individuals. However, disconfirming experiences are associated with demands on nurses' work schedules, low client motivation and non-compliance. Physician interjection is also perceived as problematical, resulting in feelings which undermine the nurses' professional integrity, and which lead to a diminished sense of self-worth.

Physiological stress responses in big gamefish after capture: observations on plasma chemistry and blood factors.

The plasma electrolytes, Na+, K+, Ca2+, Cl- and osmolarities had high values in capture-stressed big gamefish. Blood metabolites measured after stress showed glucose and lactate elevations. The activity of the plasma enzymes alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatine kinase and lactate dehydrogenase suggested tissue disruptions following severe capture stress. Haematocrit values and methaemoglobin were high in capture-stressed gamefish. The plasma chemistry of resting and capture-stressed snapper (Chrysophrys auratus) was studied for comparison. Specific differences in plasma biochemistry appeared to be the result of different strategies of fish behaviour during capture.

Acute inhalation toxicity of aliphatic (C1-C5) nitrites in rats.

The 4-hr inhalation LC50 was determined for methyl-, ethyl-, n-propyl-, n-butyl-, isobutyl-, and isopentyl nitrite in Sprague-Dawley rats. LC50 values were 176, 160, 300, 420, 777, and 716 ppm, respectively. The dose-mortality curves were characterized by extremely steep slopes. Toxic signs observed during exposure included cyanosis, prostration, and rarely, convulsions. There were no effects of exposure on body weight gain during a 14-day postexposure observation period. Signs of pulmonary hemorrhage were apparent in rats which died during exposure but were much less prominent in rats sacrificed at study termination. No animals died after cessation of exposure, and rapid recovery was apparent after exposure. Concentration X Time (CT) relationships suggested that the actual concentration was more important than the "dose" in determining the lethal effects of inhalation exposure to nitrites. Because of the extremely steep dose-mortality curves, the aliphatic nitrites are more hazardous than the LC50 values would indicate.

Lugol's iodine: its effect on thyroid blood flow in patients with thyrotoxicosis.

It has been established practice for 60 years to prepare thyrotoxic patients undergoing thyroidectomy with Lugol's iodine. However, evidence in support of its claimed benefits, namely a reduction in the vascularity and friability of the toxic thyroid gland, is scanty. We have therefore determined the effect of Lugol's iodine on thyroid blood flow, as measured by thyroid uptake of thallium-201, in nine patients with Graves' disease and one euthyroid patient. Thallium-201 uptake, as well as serum thyroxine and triiodothyronine, fell significantly after treatment with iodine. Although not correlated with thyroid function tests, thallium-201 uptake was significantly correlated with thyroid weight. These results support the contention that thyroid blood flow is reduced in thyrotoxic patients treated with Lugol's iodine.

Continuous comparison of transcutaneous and arterial oxygen tension in newborn infants with respiratory illnesses.

Transcutaneous oxygen tension (tcPO2) measured by two skin electrodes of different design, and arterial oxygen tension (PaO2) measured by an intravascular oxygen electrode, were continuously compared for periods of 6--27 h in 45 newborn infants with respiratory illnesses. One skin electrode (Dräger) had three microcathodes surrounded by a heated ring-shaped anode and the other (Roche) a large heated cathode. The electrodes were calibrated in vitro; 44 degrees C was found to be a suitable electrode temperature for the estimation of Pao2. tcPo2 recorded by the electrode with the microcathodes estimated Pao2 reasonably accurately for 6 h without the necessity for re-siting. tcPao2 recorded by the electrode with the large cathode gave a similar estimate of Pao2 for 3 h, but then tcPao2 often fell relative to Pao2. This fall was probably caused by skin changes at the electrode site. Poor skin perfusion causing underestimation of Pao2 by tcPo2 could not be identified by a number of methods tried.

Continuous comparison of in vitro and in vivo calibrated transcutaneous oxygen tension with arterial oxygen tension in infants.

Transcutaneous PO2 simultaneously recorded by Drager and Radiometer electrodes on the abdominal skin was compared for six-hour periods with aortic PaO2 recorded by a Searle intravascular oxygen electrode. Ten newborn infants with serious respiratory illnesses, six of whom needed mechanical ventilation, were studied. The skin electrodes were heated to 44 degrees C and calibrated first in vitro, and then in vivo against the infant's PaO2. The results showed that 1) after in vivo calibration both skin electrodes gave an accurate estimate of PaO2 for six hours without resiting of the electrodes; 2) the Radiometer electrode gave as satisfactory an estimate of PaO2 after in vitro as after in vivo calibration; 3) the Drager electrode gave a significantly less accurate estimate of PaO2 after in vitro than after in vivo calibration; 4) no evidence suggesting that peripheral vasoconstriction interfered with the accuracy of estimation of PaO2 by the skin electrodes was found.