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Biomedical subjects

Y Mahler

Publications and source records attributed to Y Mahler.

14 recordsLinked to original sources
PubMed1992

Intra-articular pressure measurements in patients with suddenly developing, severely limited mouth opening.

A condition of sudden, severe, and persistent limited mouth opening, which readily responds to arthrocentesis, is postulated to be the effect of a vacuum between disc and fossa in the upper compartment of the temporomandibular joint. In 16 patients with this condition, the negative intra-articular pressure was found to be significantly lower (mean, -82.6 +/- 25.4 mm Hg) than in the control group (mean, -7.7 +/- 2.5 mm Hg) (P less than .0001). It is suggested that the process underlying the vacuum effect starts with persistent pressure (eg, clenching) resulting in the viscoelastic disc being pressed flat against the fossa. Immediately on cessation of the pressure, the disc resumes its natural biconcave shape, but its rims remain fastened to the fossa. The consequent increased negative pressure in the closed space created firmly anchors the disc to the fossa and any attempt to elicit condyle and disc sliding will only stretch the joint capsule and cause pain. This, in turn, will reflexly prevent the pterygoid muscle from exerting sufficient force to pull the disc and thus release the vacuum. This chain of events may account for the severe and persistent limitation in jaw movement and for the easy reversal of the condition by simple nonsurgical treatment.

Adolescent↗
PubMed1992

Diagnostic value of computer analysis of multipeaked EMG spikes.

Computer analysis of absolute number of peaks per second and the number of peaks in the multipeaked spikes/sec was carried out in the EMG interference recordings of 5 healthy, 6 myopathic and 8 neuropathic subjects. The purpose of the study was to detect diagnostically different patterns. A spike was considered multipeaked if it had 6 or more peaks. The amplitude of elimination (baseline) was examined at 1: 5, 1: 10 and 1: 15 of the average amplitude per second. Both the number of peaks and the number of peaks in multipeaked spikes in the neuropathic and myopathic muscles showed statistically significant differences when compared to healthy muscles. This technique could give an indication for the differential diagnosis of myopathic, neuropathic or healthy state of the muscle.

Arm↗
PubMed1978

A new hazard in the use of an external demand pacemaker.

Ventricular pacing by a Medtronic model 5880A external demand pacemaker was shown to be inhibited as long as the metal coverplate of the pacemaker was touched with bare hands. The asystolic periods were induced by a previously undescribed malfunction of the pacemaker, inherent in its structure. This phenomenon occurred when both patient and physician were isolated from any main operated instrument. It could be demonstrated that pacer inhibition was induced by capacitive coupled 50 Hz fields from the environment, activating the sensing mechanism through the metal coverplate. The plastic covered Medtronic model 5840 pacemaker does not have such undesirable characteristics.

Electrocardiography↗
PubMed1977

Fetal movements recorder, use and indications.

A new device for recording fetal movements is presented. This device is composed of 2 sensors, incorporating a highly sensitive piezoelectric material. It is sensitive to rapid straining forces such as fetal movements and relatively insensitive to steady, slow movements such as uterine contractions and maternal respiratory movements. In this study of 20 women, the sensors were placed on 2 different zones of the abdomen, usually above the umbilicus. There was a good correlation between fetal movements recorded by the device and those felt by the patients. Seventy percent of all observed fetal movements recorded by the device were registered simultaneously by the women. The device recorded 90.4 percent and the women recorded 79.7 percent of all such movements.

Female↗
PubMedDate not supplied

Computer processing of artifact and arrhythmias in heart rate variability analysis.

Analysis of heart rate variability (HRV) with Holter monitoring is often difficult due to excessive artifacts and arrhythmias. While short sudden surges are treated successfully by most methods, slow heart rate (HR) variations, nocturnal trapezoidally-shaped HR increases and special types of arrhythmias which are similar to normal HRV fluctuations may distort further time domain and spectral analysis. This paper examines the advantages and disadvantages of different methods for preprocessing of HR data. We have developed the following approach to the analysis of HRV. (1) A combination method based on the absolute difference between HR values and both the last normal HR value and an updated mean is used for removal of artifacts and arrhythmias. This method can detect both sudden surges in HR values as well as longer periods of noise combined with slow normal variations. An additional stage of wild point removal is then optionally applied. (2) Certain special problems such as large T-waves, bigeminal rhythm, slow HR variations and nocturnal trapezoidally-shaped HR increases are also identified. Although none of the algorithms can be applied successfully to all cases, the final computer analysis for preprocessing described in the present study has proved to be superior to the simplified methods which are usually used and provides more suitable data for HRV analysis.

Algorithms↗
PubMedDate not supplied

The relationship between systolic blood pressure and microvascular resistance in non-diabetic and diabetic subjects.

Skin blood flow and microvascular resistance were measured in the feet of hypertensive and normotensive subjects by the non-invasive transient thermal clearance method. Skin blood flow decreased and microvascular resistance increased as a function of systolic brachial blood pressure for the non-diabetic subjects who were not treated by vasoactive medication. The relationship between blood flow and systolic blood pressure for diabetic patients and for patients who were treated by enalapril was poor. The average resistance for non-diabetic patients treated by enalapril was lower than that of untreated non-diabetic subjects. For diabetic patients no significant difference in resistance between enalapril treated and untreated patients was found. The results demonstrate that for non-diabetic patients the role of microvascular resistance in hypertension is significant while it is less important in diabetic patients.

Adult↗