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Biomedical subjects

J M Van De Water

Publications and source records attributed to J M Van De Water.

13 recordsLinked to original sources
PubMed2004

Clonogenic analysis reveals reserve stem cells in postnatal mammals. II. Pluripotent epiblastic-like stem cells.

Undifferentiated cells have been identified in the prenatal blastocyst, inner cell mass, and gonadal ridges of rodents and primates, including humans. After isolation these cells express molecular and immunological markers for embryonic cells, capabilities for extended self-renewal, and telomerase activity. When allowed to differentiate, embryonic stem cells express phenotypic markers for tissues of ectodermal, mesodermal, and endodermal origin. When implanted in vivo, undifferentiated noninduced embryonic stem cells formed teratomas. In this report we describe a cell clone isolated from postnatal rat skeletal muscle and derived by repetitive single-cell clonogenic analysis. In the undifferentiated state it consists of very small cells having a high ratio of nucleus to cytoplasm. The clone expresses molecular and immunological markers for embryonic stem cells. It exhibits telomerase activity, which is consistent with its extended capability for self-renewal. When induced to differentiate, it expressed phenotypic markers for tissues of ectodermal, mesodermal, and endodermal origin. The clone was designated as a postnatal pluripotent epiblastic-like stem cell (PPELSC). The undifferentiated clone was transfected with a genomic marker and assayed for alterations in stem cell characteristics. No alterations were noted. The labeled clone, when implanted into heart after injury, incorporated into myocardial tissues undergoing repair. The labeled clone was subjected to directed lineage induction in vitro, resulting in the formation of islet-like structures (ILSs) that secreted insulin in response to a glucose challenge. This study suggests that embryonic-like stem cells are retained within postnatal mammals and have the potential for use in gene therapy and tissue engineering.

Animals↗
PubMed1986

Impedance cardiography. Current status and clinical applications.

Impedance cardiography is a highly reproducible, rapid and safe method for the evaluation of cardiac performance in the clinical setting. Measurements of stroke volume (SV), end diastolic volume (EDV), and end systolic volume (ESV) with calculation of cardiac output (CO) were obtained in normal, healthy people (group 1, n = 21) and in patients with congestive heart failure (group 2, n = 18). Individuals were placed on a tilt table and cardiac profiles (measurements of CO, SV, EDV, and ESV) were performed at 45 degrees head up, 15 degrees head up, and supine. Group 1 responded by increasing CI from 2.9 +/- 0.81 L/min/M2 at 45 degrees to 3.3 +/- 1.0 L/min/M2 at 15 degrees to 3.7 +/- 1.0 L/min/M2 supine. There was no corresponding rise seen in group 2, with CIs of 2.1 +/- 0.83 L/min/M2, 2.0 +/- 0.78 L/min/M2 and 2.0 +/- 0.76 L/min/M2 at each position, respectively. In addition, while the EDV increased at each position in group 1 (45 degrees: 71 +/- 21 cc/M2, 15 degrees: 88 +/- 26 cc/M2, Supine: 102 +/- 29 cc/M2), no such increase was evident in group 2 (45 degrees: 57 +/- 29 cc/M2, 15 degrees: 52 +/- 20 cc/M2, Supine: 60 +/- 24 cc/M2). The inability of group 2 patients to elevate CI and the absence of any discernible change in EDV suggests an insufficiency of cardiac reserve with noncompliant ventricles. This information is currently being used to assess operative risk and to study effects of treatment modalities.

Cardiac Output↗
PubMed1983

Predicting success in limb salvage.

While success in revascularization procedures for severe arterial insufficiency--limb salvage--demands a technically correct operation, the adequacy of the outflow system is equally important. An outflow index (phi), the percentage drop in femoral artery pressure following an intra-arterial injection of papaverine, was developed. The predictive value of this index was demonstrated in a prospective study of 44 limbs in which an aortoiliac procedure with profundoplasty was done for multilevel disease. In the operations considered completely successful (n = 27), the mean value of phi was 37 +/- 8 per cent; this was significantly greater (P less than 0.001) than the mean value of 16 +/- 9 per cent found for those operations (n = 17) deemed to have been unsuccessful on the basis of rigorous postoperative criteria. This finding not only proves the efficacy of the index, but emphasizes the importance of an outflow system with the ability to accept more blood.

Arterial Occlusive Diseases↗
PubMed1980

Hyperemic response for accurate diagnosis of arterial insufficiency.

Monitoring of calf (or ankle) blood pressure during reactive hyperemia after thigh arterial occlusion allows differentiation of normal from abnormal responses and of distal (femoropopliteal [FP] system) disease from proximal (aortoiliac [AI] disease. The hyperemic response of 106 lower extremities representing three disease states--FP (N = 19), AI (N = 15), and combined (AI plus FP)(N = 16)--were compared with each other and with 20 normal subjects and 36 asymptomatic diabetics. Not only were the three disease states readily distinguished from the very similar normal subjects and asymptomatic diabetics, but there was a highly significant difference between FP disease and AI disease up to 150 s. This is a simple, inexpensive, and reliable test that can be used at the bedside to determine levels of severe disease, especially in the claudicator, who may not have a critical stenosis under resting conditions.

Adult↗
PubMed1980

Calibrated impedance plethysmograph.

The accuracy of quantitative pulse-volume measurement with a calibrated electrical impedance plethysmograph was determined on a laboratory limb-segment model. Changes in electrical impedance detected via a tetraprolar electode configuration were related to pulse-volume changes by the parallel-impedance model described by Nyboer et al. (The Impedance Plethysmograph: An Electrical Volume Recorder. Natl. Res. Council, Comm. Aviation Med. 149, 1943). The instrument employed in this study calculated pulse volume assuming two standard conditions: distance between voltage electrodes, l, is 15 cm, and resistivitiy of blood, rho b, is 150 omega x cm. The effects of varying tissue and blood resistivity, pulse frequency, and electrode distance were investigated. Measurements under three ionically distinct conditions gave an overall accuracy of 96.6% with correlation coefficients of 0.99 for each condition. Measurement accuracy was maintained with a pulse-frequency variation in the range of 15-150 pulses/min and with application of correction factors for electrode distance and blood resistivity other than the standard values.

Electric Conductivity↗
PubMed1979

Patient and operation selectivity. The peripheral vascular laboratory.

Careful use of the data from the vascular laboratory has resulted in better patient and operation selectivity in peripheral arterial disease of the lower extremities. Using the combination of segmental pressure measured with an ultrasonic Doppler and flow as approximated by the measurement of the rate of pulsatile volume change with a calibrated plethysmograph, objective criteria were established for arterial insufficiency. Using a two cuff technique, resistance indices were established to distinguish femoropopliteal from aortoiliac disease. The ratio of angiograms to femoropopliteal and aortoiliac operations has been reduced from an earlier value of almost 3/1 to the present value of approximately 1/1.

Arterial Occlusive Diseases↗
PubMed1979

Limb salvage and selectivity.

In a group of properly prepared poor risk patients with advanced atherosclerosis of both the aortoiliac and femoropopliteal segments, a combined procedure, extra-anatomic bypass with an extended profundoplasty, was used for successful salvage of their ischemic--mean calf pressure=27 millimeters of mercury--limbs. Prediction of success versus failure could be determined on neither clinical nor angiographic-anatomic grounds but was possible using two simple measurements: a large aortoiliac differential pressure--deltaP--between inflow pressure obtained from a standard arm cuff and outflow pressure measured directly from the femoral artery, 89.3 millimeters of mercury versus 33.2 millimeters of mercury, p less than 0.001, and a potentially adequate outflow bed as determined by the percentage drop in outflow [(deltaPo/Po) per cent] upon papaverine injection, 36.3 versus 11.3 per cent, p less than 0.001. These values became an important part of the selection scheme developed in the approach to 24 ischemic limbs.

Aged↗
PubMed1977

Noninvasive assessment of the peripheral vascular system.

Forty-five limbs varying clinically from normal through moderate to severely ischemic were studied by noninvasive measurements of both arterial blood pressure and perfusion. From the values plotted on a two-coordinate system, they arranged themselves well into three clinical categories: (1) normal, (2) intermittent claudication, and (3) ischemia or ulceration and rest pain. Good clinical responses to arterial reconstruction were corroborated by postoperative measurements. Reinforcing the results of one measurement with those of the other has provided an objective, numerical, and graphic basis for decisions regarding the advisability of angiography or arterial reconstructive procedures or both. To date, almost 400 patients have been evaluated by these techniques.

Adult↗