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Biomedical subjects

R L Vereecken

Publications and source records attributed to R L Vereecken.

15 recordsLinked to original sources
PubMed1977

Frequency analysis of the electromyographic activity in striated pelvic floor muscles: a preliminary report.

A power spectrum of the electromyographic signals in urethral and anal sphincters has been analyzed in 25 patients. Different spectra are observed in each muscle, with higher frequencies in the urethral sphincter. The high frequencies are manifest at short brisk contractions (e.g. cough) and disappear quicly during a sustained voluntary contraction. High frequencies are less pronounced in stress incontinence, but increase in spastic syndromes. The hypothesis is advanced that the proportion of active tonic and phasic motor units determines the efficiency of sphincter reactions.

Action Potentials↗
PubMed1977

Leiomyosarcoma of the prostate: a case report.

A case of leiomyosarcoma of the prostate in a 26-year-old man is presented. The short duration of symptoms, the typical sensation at rectal palpation, and the sudden fast increase in growth are stressed. The bad prognosis justifies an agressive therapeutical approach.

Adult↗
PubMed1976

Is the intrinsic bladder pressure a reliable parameter?

Simultaneous pressure recording in different organs shows that voluntary movements as straining, Valsalva maneuver, cough, are easy recognizable. Spontaneous pressure waves in the rectum may give the impression of uninhibited bladder contractions if subtracted from the total bladder pressure.

Cough↗
PubMed1976

The physiology and pathophysiology of the ureter.

A review is given of the theories concerning the transport of urine from the calyces to the bladder. The application of hydrodynamic laws on the propulsion of urine, the visco-elastic characteristics of the ureter wall, the myogenic versus the neurogenic origin of spontaneous activity of the ureter and the presence of pacemaker areas, are discussed. The changes of peristaltic activity and intraluminal pressure during obstruction, infection and reflux are summarized.

Animals↗
PubMed1975

The influence of calcium on the electrical and mechanical activity of the guinea pig ureter.

Low calcium concentration in the external medium depolarises the membrane of smooth muscle cells of the ureter and their excitability diminishes. The Ca++ dependent oscillations of the action potential disappears, while the plateau component is more resistent. Analogous reactions are observed by the addition of Ca++ antagonists such as Lantanum or Verapramil. A high Calcium concentration produces a slight hyperpolarisation, which stabilises the membrane and enhances the spike component while decreasing the plateau component of the action potential. It is possible that several drugs act indirectly on the ureter by changing the relationship between the calcium concentration of the external versus the internal medium.

Action Potentials↗
PubMed1975

The influence of potassium on the electrical and mechanical activity of the guinea pig ureter.

Increase of the external K+ concentration depolarises the ureteral muscle membrane and induces, after a transient period of increased spontaneous activity, a tonic contraction. Tetraethylammonium, in concentrations normally required for ganglion blocking activity, does not influence the ureteral activity, but in higher doses it prolonges the duration of the action potential several times and increases the intraluminal pressure. Ouabain has only an inhibitory effect on the guinea pig ureter.

Action Potentials↗
PubMed1975

The influence of sodium on the electrical and mechanical activity of the ureter.

In Sodium-deficient solutions both the electrical and mechanical activity of the ureter are reduced. The plateau component of the action potential in the smooth muscle cell of the guinea pig ureter is more affected than the oscillations. Tetrodotoxin, which blocks the action potential in nerves, does not influence activity or conduction in the ureter. This is an important argument for the myogenic conduction of activity in this tissue.

Action Potentials↗
PubMed1975

Electromyography of the perineal striated muscles during cystometry.

The electromyographic patterns of the external urethral sphincter, the anal sphincter, and the levator ani during cystometries have been analyzed. Synchronized activity changes occur during abdominal straining. Muscle fatigue is very pronounced. Activity may be less synchronized during bladder filling and micturition, even in normal cystometries. In neurogenic diseases, true dyssynergia between the striated muscles may be observed.

Anal Canal↗