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Biomedical subjects

J Hertzberg

Publications and source records attributed to J Hertzberg.

At least 19 recordsLinked to original sources
PubMed2001

Development of a noninvasive ultrasound color M-mode means of estimating pulmonary vascular resistance in pediatric pulmonary hypertension: mathematical analysis, in vitro validation, and preliminary clinical studies.

BACKGROUND: Accurate determination of pulmonary vascular resistance (PVR) is an important component in the evaluation and treatment of pediatric patients with pulmonary hypertension. We developed a novel technique, based on the concept of flow propagation, to estimate PVR noninvasively. The hypothesis is that changes in PVR cause changes in the velocity propagation (Vel(prop)) within the main pulmonary artery and that Vel(prop) can be quantified using color M-mode imaging. METHODS AND RESULTS: We tested the hypothesis using mathematical modeling, in vitro experiments, and preliminary clinical studies. The mathematical model showed that pressure and velocity tracings are closely correlated in time and that 6 to 18 ms time resolution was needed to resolve propagation times within typical main pulmonary artery lengths (2 to 5 cm). The in vitro experiments demonstrated that it was feasible to use color M-mode to measure Vel(prop) and that Vel(prop) correlated well with downstream resistance [y=(-1.01x)+22.77; R=0.96]. The method was then evaluated on patients undergoing acute pulmonary reactivity testing (n=22 measurements). Good correlation between Vel(prop) and PVR was found [y=(-1.71x)+26.0; R=0.90; SEE=2.41]. CONCLUSION: This newly developed method promises to be useful in the noninvasive evaluation of adults and children with pulmonary hypertension.

Adolescent↗
PubMed2001

Artificial neural network-based method of screening heart murmurs in children.

BACKGROUND: Early recognition of heart disease is an important goal in pediatrics. Efforts in developing an inexpensive screening device that can assist in the differentiation between innocent and pathological heart murmurs have met with limited success. Artificial neural networks (ANNs) are valuable tools used in complex pattern recognition and classification tasks. The aim of the present study was to train an ANN to distinguish between innocent and pathological murmurs effectively. METHODS AND RESULTS: Using an electronic stethoscope, heart sounds were recorded from 69 patients (37 pathological and 32 innocent murmurs). Sound samples were processed using digital signal analysis and fed into a custom ANN. With optimal settings, sensitivities and specificities of 100% were obtained on the data collected with the ANN classification system developed. For future unknowns, our results suggest the generalization would improve with better representation of all classes in the training data. CONCLUSION: We demonstrated that ANNs show significant potential in their use as an accurate diagnostic tool for the classification of heart sound data into innocent and pathological classes. This technology offers great promise for the development of a device for high-volume screening of children for heart disease.

Adolescent↗
PubMed1988

Bottle-feeding and malocclusion: is there an association?

To determine whether there is an association between bottle-feeding and malocclusion, a case control study was conducted by means of a questionnaire sent to the parents of 737 patients aged 10 to 12 years from a large private pediatric dental practice. Questions included method and duration of infant feeding, type of nipple used, pacifier use, sucking habits, history of orthodontic treatment, and parental orthodontic history. Analysis of valid responses (N = 454) showed need for treatment to be associated only with history of parental orthodontic treatment (P less than 0.05). A trend toward association of bottle-feeding with need for orthodontic treatment was found in the increasing need for treatment with increasing exposure to bottle, but was of marginal significance (P = 0.058).

Bottle Feeding↗
PubMed1983

Effects of amrinone on atrioventricular conduction in the intact canine heart.

The effects of amrinone on conduction in the intact canine heart were studied. Intracardiac His-electrode catheter recordings were used to measure the functional refractory period (FRP) of the AV node and conduction time through the AV node (A2H2 interval) and in the His-Purkinje system (H2V2 interval). Amrinone (2.5 to 10 mg/kg) shortened the FRP and A2H2 in a dose-dependent manner but had no significant effect on H2V2. In hearts where AV conduction was depressed by treatment with verapamil, propranolol, or ouabain, amrinone partially reversed this depression. Amrinone also shortened the recovery time of spontaneous sinoatrial (SA) node activity following a train of rapid atrial stimulation. This effect was also observed after depression of SA nodal recovery with verapamil, propranolol, or ouabain. These results indicate that amrinone enhances AV conduction and SA nodal activity in the normal heart and may favorably influence depressed AV conduction and SA nodal activity induced by a variety of cardioactive agents.

Aminopyridines↗
PubMed1981

Crohn's disease: long-term results of surgical treatment.

Fifty-nine patients operated on for Crohn's disease during the years 1954 to 1977 were studied. The observation time was from 1 to 24 years, mean 10 years. The operative mortality was 1.7%, and alter deaths from the disease and its complications 3.4%. The general state of health at the final follow-up observation was good for the large majority of the patients. Ony four patients (7%) had marked symptoms that affected the working capacity. Forty-four percent of the patients had one or more recurrences. The average yearly recurrence rate was 6.1% in the first 10 years of observation. In the next 10 years this rate diminished to 2.2%. The recurrence rates were much lower (14%) when the margins of the resected intestine were free of the disease than when microscopic signs of the disease were present (66%). To obtain a free margin, rather wide resection and peroperative frozen-section evaluation of resection margins are recommended. Eleven out of 12 patients with shunt operations had to be operated on again.

Adolescent↗
PubMed1976

Idiopathic failure of eruption of permanent molar teeth.

Failure of permanent teeth to erupt without any known cause is a seldom occurring phenomenon. However, it brings to light our ignorance of the basic physiologic mechanism of tooth eruption. In this article we present five patients with unerupted permanent molar teeth. In all instances, no obvious cause exists. Indications for operative intervention and management are discussed, but the cases are also presented to focus attention on our lack of knowledge of the physiology of tooth eruption.

Child↗