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Biomedical subjects

M J van Putten

Publications and source records attributed to M J van Putten.

8 recordsLinked to original sources
PubMed2001

BIPLEDs in akinetic mutism caused by bilateral anterior cerebral artery infarction.

INTRODUCTION: Akinetic mutism is described as a result of many disorders. Bilateral infarction of the anterior cerebral artery (ACA) territory is reported rarely, however, often leading to akinetic mutism. CASE REPORT: We report a 70 year-old man with akinetic mutism due to bilateral ACA infarction. Electroencephalography, 24h after admission, showed bilateral independent periodic lateralized epileptiform discharges (BIPLEDs) in the frontal region and diffuse theta and polymorphic delta activity. DISCUSSION: Postanoxic encephalopathy, central nervous system infection and chronic seizure disorders are the major causes of BIPLEDs. However, BIPLEDs may occur in bilateral ACA territory infarction.

Aged↗
PubMed1999

[Central apnea in newborns].

Three neonates had diverse kinds of central apnoea. The first child, a girl aged 3 weeks, had an upper respiratory tract infection caused by the respiratory syncytial virus; she was intubated and needed ventilatory support for three days. The second patient, a boy of 17 days, had an Arnold-Chiari-malformation with apnoeas treated with a carbonic anhydrase inhibitor (acetazolamide). The third patient, a boy of 5 days, had central apnoeas of epileptic origin and was treated with phenobarbital. All three recovered well. If in an infant with apnoeas no paediatric explanation is found, and the child is neurologically at risk, it is advisable to make an EEG to determine if an epileptic substrate is present, even in the absence of motor phenomena.

Acetazolamide↗
PubMed1999

An uncommon cause of stroke in young adults.

We describe a previously healthy 48-year-old man who presented with clinical characteristics suggestive of internal carotid artery dissection, confirmed by magnetic resonance imaging. He developed a massive infarction of the left cerebral hemisphere and died after 3 days of transtentorial herniation. Post-mortem examination identified a dissection of the thoracic aorta caused by Erdheim-Gsell cystic medionecrosis, with the characteristic degeneration of the elastic fibers of the lamina media. The dissection showed an unusually large extension not only distally into both iliac arteries, but also proximally into both carotid arteries. To our knowledge, such an extensive dissection has not been described previously. Underlying vessel wall disorders of the aorta, such as Erdheim Gsell cystic medionecrosis, should be considered in young patients with spontaneous arterial dissection.

Aortic Dissection↗
PubMed1997

A silicon bidirectional flow sensor for measuring respiratory flow.

We describe a solid-state, silicon integrated, bidirectional flow sensor for respiratory applications. The sensor is a thermal vector sensor. The electronic circuitry for obtaining bidirectional sensitivity is presented together with actual application to a healthy volunteer put on mechanical ventilation. The sensor's input flow range is from -60 to +60 L/min, and its rise-time is < or = 40 ms and fall-time is < or = 60 ms. The effect of changes in gas composition as used in mechanically ventilated patients on the sensor output signal are estimated to be less than 2%. The temperature sensitivity is about -1.5% per degree Celsius.

Equipment Design↗
PubMed1994

Analysis of decaying unitary currents in on-cell patches of cells with a high membrane resistance.

Under nonideal voltage-clamp conditions, unitary currents in the cell-attached patch (CAP) configuration of the patch-clamp technique are decaying instead of rectangular. From these data, four parameters can be determined when multiple identical channels are present. We analyzed an electrical equivalent circuit of the CAP configuration. This analysis yielded, for single-channel resistance, attached-cell membrane resistance, patch resistance, and attached-cell membrane capacitance, a set of different equations to calculate their values from these four parameters. To choose the most robust equation, those that yielded the same resistor/capacitance were compared on the basis of their sensitivity for inevitable deviations of the parameters from their nominal values. The results of our theoretical study are of methodological interest: 1) because they confirm that, under special conditions, CAP measurements can be used to measure electrical membrane properties of intact cells (this is important inasmuch as the CAP is the only configuration in which the cytoplasm of cells remains undisturbed) and 2) because we identify the level of voltage clamp and the equations with which the electrical properties can be determined with optimal accuracy.

Animals↗