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Biomedical subjects

E F Bernstein

Publications and source records attributed to E F Bernstein.

At least 127 records · Page 7Linked to original sources
PubMed1979

Effect of pulseless perfusion on gastrointestinal blood flow and its distribution.

The effect of nonpulsatile (NP) arterial perfusion on gastrointestinal organ blood flow and intraorgan flow distribution was studied in 10 anesthetized (pentobarbital) dogs utilizing the radionuclide-labeled microsphere (15 micrometer) technique. Measurements of flow to the stomach, small intestine, and colon were made during a pulsatile perfusion control period and after 1- and 2-h periods of NP perfusion with a centrifugal left ventricular bypass pump (Medtronic). Total gastric blood flow (0.178 +/- 0.021 ml/min per g) as well as the partitioning of that flow between gastric subsegments such as antrum (17% of total gastric flow), body (83%), and mucosa (73%) was not significantly altered during the 2-h period of NP perfusion (P greater than 0.20). Similarly, flow to the intestine showed significant change during NP perfusion. Under conditions of equivalent hemodynamic states (mean perfusion pressure), nonpulsatile arterial perfusion results in no significant alteration in gastrointestinal blood flow or its intraorgan distribution.

Animals↗
PubMed1979

Renin secretion in the chronically perfused pulseless calf. Evidence for failure of stimulation by decreased pulse pressure.

To study the influence of arterial pulse pressure on renin release, a chronic pulseless calf preparation was developed using a centrifugal left ventricular bypass blood pump. After pump implantation and recovery, control measurements of renal vein and arterial plasma renin activity, arterial pressure, and renal artery flow were obtained. The centrifugal bypass pump rate then was increased to capture cardiac output completely, and nine conscious calves were perfused in a nonpulsatile manner (pulse pressure less than 5-10 mm Hg) for 48 hours. Nonpulsatile perfusion was well tolerated and serum sodium, potassium, creatinine, and blood urea nitrogen were unchanged during bypass. Mean arterial pressure remained relatively constant [114 +/- 3 (SE) mm Hg] during bypass, and was not significantly changed from control. Although renal blood flow decreased slightly from control (667 +/- 84 ml/min) during the nonpulsatile perfusion period (555 +/- 73 ml/min), renin secretion did not increase significantly from control (482 +/- 81 ng angiotensin I/ml per hr per min) during the bypass period (531 +/- 99). A diurnal cycle of renin secretin was observed during the pulseless perfusions. These data document the lack of any significant stimulatory influence of decreased pulse pressure on renin secretion in a chronic awake calf model.

Animals↗
PubMed1979

A system for restraint and anesthesia in calves.

A mobile calf enclosure was developed which incorporated a hydraulic hoist and sling for the care of calves. This apparatus permitted induction of and emergence from anesthesia in an erect posture, which decreased the risk of aspiration and postoperative pulmonary problems. Fifty-two surgical procedures requiring general anesthesia have been performed on 29 calves during the last 2 years with only one operative death, and calves have been maintained within the enclosure for periods up to 1 month.

Anesthesia, Inhalation↗
PubMed1978

The specificity of the reaction of collagen with platelets.

1. Human platelets will react with a number of different collagens from guinea-pig to ostrich. 2. Human skin collagen when treated with pepsin does not react with human platelets. 3. Calf platelets display a different pattern of reactivity than that of human platelets.

Animals↗
PubMed1978

The importance of combined multisegmental pressure and Doppler flow velocity studies in the diagnosis of peripheral arterial occlusive disease.

The value of combined multisegmental pressures and quantitative Doppler flow velocity determinations in the preoperative vascular laboratory evaluation was analyzed in 100 consecutive patients with angiographically documented peripheral arterial occlusive disease. Several new observations were made: (1) erroneously normal or even high segmental pressure readings appear to be caused by increased arterial wall stiffness and may produce falsely elevated or erroneously normal pressure, suggesting less disease than exists, especially when only ankle pressure screening is used. (2) The addition of quantitative flow velocity determinations significantly improved the reliability of diagnostic decision making. The diagnosis of proximal arterial occlusive disease based on combined pressure-velocity measurements was confirmed angiographically in 143 of 148 limb studies (96.6%), including several with normal pressures and reduced velocity values--a pressure-velocity dissociation. (3) A decrease of the leg segment:arm pressure ratio combined with only a slight reduction of velocity indices suggests a stenosis with good local collateral flow and vessel patency at the site of measurement--a reversed pressure-velocity dissociation. (4) A decreased lower limb segment/arm pressure ratio combined with a significant reduction of velocity indices is evidence of arterial stenosis with poor local collateral flow. The combined multisegmental pressure and velocity evaluation of patients suspected of arterial occlusive disease substantially increases the reliability of noninvasive diagnosis and offers a new level of differential diagnostic interpretation.

Ankle↗
PubMed1978

Fallibility of the platelet count and fibrinogen concentration in evaluating circulatory assistance technique--a plea for turnover studies.

Platelet and fibrinogen kinetics were investigated in calves undergoing prolonged extracorporeal left ventricular bypass in which both platelet and fibrinogen concentrations were within or above the normal range. Sequential survival time measurements documented significant continuing destruction of both platelets and fibrinogen during the course of these perfusions, with markedly elevated turnover rates of both components. The ineffectiveness of ASA and Persantine to return these functions to normal suggests that the mechanism of destruction includes trauma from the moving parts of the system, including the rotor and bearing seal, as well as surface-induced injury from the conduits and pump housing. Kinetic studies appear to be an essential requirement in the evaluation of blood destruction and subject tolerance of prolonged circuitry assistance devices.

Animals↗
PubMed1977

Axillary, subclavian, and brachiocephalic vein obstruction.

The consequences of occlusion of a major upper extremity vein were evaluated in eight patients with effort thrombosis, ten with thrombosis secondary to intimal injury, six with extrinsic compression, and one hypercoagulable patient, all of whom were followed for an average of 4 years. Twenty-two patients had venography, which confirmed the diagnosis but often failed to define the proximal extent of obstruction. Thirteen patients had noninvasive hemodynamic studies which did not corroborate chronic morbidity, but which were valuable in assessing the effect os specific therapy. Twelve patients were treated with anticoagulants, and six had operative removal or bypass of the obstruction. Three patients had pulmonary emboli; two embolized while on anticoagulants and both died. Swelling, pain, prominent veins, and easy fatigability of the affected extremity were the late sequelae of occlusion. Chronic morbidity was more dependent on etiology than on initial treatment. Thrombosis secondary to intimal injury caused no persistent symptoms, whether treated with anticoagulants or not. Effort thrombosis was intermediate: three fourths complained that their affected arm tired easily and half had prominent veins or persistent swelling. All of those with obstruction secondary to extrinsic compression had easy fatigability. The majority also had concomitant swelling, pain, and prominent collaterals. Operative treatment produced objective improvement in venous outflow but often was unsuccessful in relieving symptoms, particularly in patients with obstruction from extrinsic compression.

Adolescent↗