Densities in dependent lung regions during anaesthesia: atelectasis or fluid accumulation?

In previous studied with computed tomography (CT) prior to and during general anaesthesia, we found that densities developed in dependent parts of the lungs immediately after induction of anaesthesia in all examined patients. It was suggested that the densities were atelectases created by compression of lung tissue but an alternative explanation could be accumulation of extravascular fluid in the lung tissue and/or in the pleural space. In the present study the nature of the densities was analysed in further detail. Injections of contrast medium into the pleural space revealed that the densities were located in the lung tissue and not in the pleural space. By injecting contrast medium intravenously and repeating the CT scanning over a 2-min period the passage of contrast through the major vessels and the lung densities could be studied. The transit time of the contrast medium was of the same magnitude in the densities and the major lung vessels. This indicates that there were no regions with an increased amount of extravascular fluid to delay the contrast passage. These findings oppose the idea of fluid accumulation as the cause of the densities, while atelectasis remains the most plausible explanation.     

High-dose intravenous immunoglobulin therapy improved muscle strength in a patient with multifocal motor neuropathy and antibodies against the glycolipid LK1

We report improvement in muscle strength in a patient with multifocal motor neuropathy (MMN) when given high-dose intravenous immunoglobin (i.v.-Ig) treatment. The patient had asymmetrical limb weakness, atrophy and absent or weak reflexes, but no sensory disturbances. Neurography showed multiple conduction blocks in peripheral motor nerves but no sensory nerve abnormalities. Serum and anti-GM1 antibodies were not found, however, the patient had serum antibodies against the glycolipid LK1, an epitope found both in glycolipid and also in some glycoproteins in peripheral nerve myelin. Muscle strength improved 5 days after i.v.-Ig therapy, and lasted about 10 weeks. Repeated courses of treatment resulted in similar improvement. This is, to our knowledge, the first patient reported with MMN found to have antibodies against the glycolipid LK1.     

Inward rectifying potassium channels in human malignant glioma cells

Human glioma cells obtained from established cell lines (Tp-276MG, Tp-301MG, Tp-378MG, Tp-483MG and U-251MG) were analyzed for the presence of ion channels with the tight-seal voltage clamp technique. The current-voltage relation revealed a marked inward rectification at hyperpolarizing voltages, due to the presence of inward rectifying K-channels in cells from all studied cell lines. These channels were conducting when the membrane potential was more negative than the K-equilibrium potential. The slope conductance for the inward K-currents (g_Ki) was affected both by [K⁺]_i and [K⁺]₀. g_Ki was proportional to [K⁺]₀ raised to 0.35 or 0.50, of which the larger value was measured in the presence of low [K⁺]_i (25mM). The rectification was not significantly different in cells perfused with Mg-free EDTA-buffered internal solution. Tl⁺ was 3.5 times more permaant than K⁺. g_ki was blocked by Cs⁺ (1 mM) in a voltage-dependent way (more effective in the hyperpolarized membrane), and by Na⁺ (154 mM) depending on voltage and time. From measurements of unitary current events in membrane patches (outside out or cell attached) the conductance of the single inward rectifying channel was estimated to be 27 ± 7 pS. This type of ion channel may be important for K-uptake by glial cells and hence for the K-homeostasis in the brain.     

Partial albinism with immunodeficiency: a rare syndrome with prominent posterior fossa white matter changes.

PURPOSE: To describe our experience in infants with partial albinism and immunodeficiency (PAID), a rare, recently recognized, probably autosomal recessive disorder. PATIENTS AND METHODS: Five infants suffering from this disease were examined with CT of the brain and four of these patients also underwent MR. Four of the five children also underwent follow-up CT or MR exams. RESULTS: Three of the patients followed with serial examinations demonstrated a rapid progress of white matter changes together with a loss of brain tissue over a few months. In all four patients subjected to follow-up, the posterior fossa white matter structures were severely involved during the course of the disease. CONCLUSIONS: This syndrome should be added to the list of demyelinating diseases, and should be kept in mind when white matter changes are prominent in the posterior fossa.     

Insulin regulates the 35 kDa IGF binding protein in patients with diabetes mellitus

The serum levels of the low molecular form of insulin-like growth factor binding protein (IGFBP) was determined in 56 outpatients with diabetes mellitus by a radioimmunoassay developed for amniotic 35 kDa IGFBP. The mean level of 35 kDa IGFBP was found to be threefold higher in insulin dependent diabetes mellitus (IDDM), 112 +/- 13 ng/ml, than in age matched controls, 37 +/- 2 ng/ml, while the mean level in non-insulin dependent diabetes mellitus (NIDDM), 16 +/- 2 ng/ml, was decreased. In hospitalized IDDM patients there was a significant correlation (r = 0.91, p less than 0.01) between fasting blood-glucose and 35 kDa IGFBP levels, not found in NIDDM patients. During insulin infusion the 35 kDa IGFBP levels declined with a half-life of 60-120 min. The decline in IGFBP continued even after the establishment of steady state B-glucose at 4.7 mmol/l. In conclusion, the elevated 35 kDa IGFBP levels in IDDM can be attributed to insulin deficiency and may reflect a reduced bioavailability of the IGFs at the target cells.     

Nerve conduction in the hands of vibration exposed workers.

Symptoms of peripheral neuropathy in the hands are common among workers using vibrating tools. The mechanism for this and its relation to carpal tunnel syndrome (CTS) was studied in workers exposed to vibration at their workplace (17), along with a control group of healthy construction workers with heavy manual work but without vibration exposure (10). Patients with uni- or bilateral CTS (11) and a group of healthy volunteers without manual work (9) were included for comparison. Median nerve conduction velocities were measured both over the carpal tunnel and in a more distal segment. Vibration exposed workers had similar conduction velocities to unexposed construction workers. The subgroup of vibration exposed patients with symptoms from the hands had normal conduction in the ulnar nerve but demonstrated a decrease in median nerve conduction comparable (but less pronounced) with the CTS group. On a group basis these results indicated that the median nerve is most vulnerable for hand-arm vibrations. However, the conduction defects were not pronounced enough to diagnose CTS in most individual cases.     

CT and MR of the brain in disorders of the propionate and methylmalonate metabolism.

PURPOSETo present the CT and MR findings in children with propionic and methylmalonic acidemia.METHODSTwenty-three new patients with methylmalonic and 20 with propionic acidemia were examined with CT and/or MR of the brain. In total 52 CT and 55 MR studies were done. Twenty-six previously published cases were also reviewed.RESULTSThe findings were similar in the two syndromes. During the first month of life the examinations were either normal or showed white matter attenuation. Later during the first year moderate or even severe widening of sulci and fissures was seen, especially in infants with propionic acidemia. During therapy, these changes often resolved, especially in the patients with methylmalonic acidemia. Mild to moderate delay in myelination was also a common finding in both disorders. Basal ganglia changes, predominately in the globus pallidus, were seen in five patients with methylmalonic acidemia and in two children with propionic acidemia; in two patients these changes were transient.CONCLUSIONChildren who have methylmalonic or propionic acidemia, in addition to widening of cerebrospinal fluid spaces and some delay in myelination, also often show symmetric involvement of the basal ganglia.     

Mechanism of anoxic conduction block in mammalian nerve

The mechanism by which anoxia blocks impulse conduction was studied in isolated sciatic nerves from the rat. The desheathed nerve was mounted in a recording chamber, and the compound action potential (CAP) was measured at controlled temperature (23 and 37 degrees C). When the nerve was irrigated with nitrogenated Ringer's solution compound action potential decreased to 50% in 10 min at 37 degrees C and in 35 min at 23 degrees C, whereas in oxygenated solution compound action potential decreased less than 5% in 60 min. A Na-free nitrogenated solution similarly caused anoxic block, that is the effect was independent of impulse activity. Ouabain (1 mM) decreased compound action potential by only ca. 4% in 30 min, and the effect of anoxia was delayed in presence of ouabain. Dinitrophenol (0.05 mM) reduced compound action potential to 50% in 5 min. These findings indicated that the anoxic block was not related to changes in axonal concentration of Na or K following impulse activity or inhibition of Na-K-ATPase. Instead the findings imply that the anoxic block is due to inactivation of Na-channels as a consequence of inhibition of another ATP-dependent process in the axon.     

Long-range temporal correlations in electroencephalographic oscillations: Relation to topography, frequency band, age and gender

Presence of long-range temporal correlations in neuronal oscillations is thought to be beneficial for a reliable transfer of information in neuronal networks. In the present study long-range temporal correlations in electroencephalographic (EEG) neuronal oscillations were characterized with respect to their topography, frequency-band specificity (alpha and beta oscillations), gender and age. EEG was recorded in 91 normal subjects (age 20-65 years) in a resting condition. The amplitude of ongoing alpha and beta oscillations was extracted with band-pass filtering and Hilbert transform, and long-range temporal correlations were analyzed with detrended fluctuation analysis. The topography of long-range temporal correlations was comparable for alpha and beta oscillations, showing largest scaling exponents in the occipital and parietal areas. This topography was partially similar to that of the power distribution and a weak positive correlation was observed between long-range temporal correlations and power of neuronal oscillations. Long-range temporal correlations were stronger in alpha than beta oscillations, but only in a few electrode locations in the left hemisphere. In both frequency bands long-range temporal correlations were stronger in males than in females and were largely unaffected by the age of the subjects. It is hypothesized that the idling state of the occipital areas in the closed-eyes condition may explain both large power values and pronounced long-range temporal correlations in this region.