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Biomedical subjects

J D Gallagher

Publications and source records attributed to J D Gallagher.

48 records · Page 3Linked to original sources

Effects of colloid or crystalloid administration on pulmonary extravascular water in the postoperative period after coronary artery bypass grafting.

The effect of postoperative fluid management on pulmonary extravascular thermal volume (ETVL) as in index of pulmonary extravascular water after coronary artery bypass grafting was compared, using the thermal-dye technique, among five patients who received 5% albumin (group A), five patients who received 6% hydroxyethyl starch (group H), and five who received lactated Ringer's solution (group C). Intraoperatively, all patients received lactated Ringer's solution intravenously, and the cardiopulmonary bypass (CPB) circuit prime included 5% albumin. No statistically significant changes in ETVL occurred postoperatively in any group, nor did ETVL differ significantly between groups. After CPB, colloid osmotic pressure (COP) significantly decreased and pulmonary artery wedge pressure (WP) and the WP-COP gradient significantly increased in each group, implying an increase in transcapillary fluid flux. Cardiac index changed variably. Pulmonary shunt fraction (Qsp/Qt) did not change in groups A and C but decreased during CPB in group H (from 0.22 +/- 0.03 to 0.16 +/- 0.11). Postoperatively, patients in the three groups received similar volumes of fluids and had similar perioperative weight gains. By the next morning (AM1), COP increased in all groups, returning to levels noted before CPB in group C, and exceeding these levels in groups A and H. Wedge pressure was similar in all three groups on AM1. PaO2 decreased significantly, and alveolar-arterial oxygen partial pressure difference increased significantly in all groups on AM1. In Group H, Qsp/Qt returned to levels observed before CPB by AM1 (0.27 +/- 0.09). We conclude that in patients without postoperative increases in WP, ETVL changes minimally during CPB and is not influenced by the type of fluid administered as the primary volume replacement in the postoperative period.

Aged↗

The effect of ventilation on systemic blood gases in the presence of left ventricular ejection during cardiopulmonary bypass.

The effect of pulmonary ventilation upon systemic arterial blood gases during cardiopulmonary bypass in the presence of left ventricular ejection was evaluated in 20 adult male patients undergoing coronary artery bypass grafting. Following rewarming, establishment of a sinus rhythm, and production of a pulse pressure of at least 20 mm Hg on the arterial pressure trace caused by left ventricular ejection, arterial blood gases were obtained from the arterial and venous extracorporeal circuits and the radial arterial cannula. Patients were then randomly assigned to a nonventilation (n = 10) or a ventilation (n = 10) group. The ventilation group was given 10 breaths/min with 100% oxygen at a tidal volume of 10 ml/kg. Whereas the nonventilation group received apneic oxygenation at zero end-expiratory pressure. After 5 minutes the arterial blood gas data were again obtained. Significant findings (p less than 0.05) included decreases in systemic carbon dioxide tension and increases in systemic pH in the ventilation group and decreases in systemic oxygen tension in the nonventilation group. Although the changes in the arterial blood gases were significant, these changes occurred well within the limits of clinical acceptability. It is concluded that left ventricular ejection for short periods during full cardiopulmonary bypass does not necessitate pulmonary ventilation.

Aged↗

Emergency guide wire pacing: new methods for rapid conversion of a cardiac catheter into a pacemaker.

We developed a new electrode to convert rapidly a previously inserted pulmonary artery or left ventricular catheter into a pacemaker. One method of doing this is by withdrawal of the pulmonary artery catheter from the pulmonary artery to the right ventricle by pressure control, and a Teflon-coated guide wire, stripped of 5 mm of insulation at its tip, is advanced through the catheter to contact the endocardium. In the second method, the pacing electrode is advanced through the distal lumen of the catheter while it is positioned within the pulmonary artery and withdrawn into the right ventricle while pacing. Finally, a third method involves advancement of the guide wire electrode into the left ventricle through a pigtail catheter. To pace, the guide wire electrode is connected to the cathode of a pacemaker referenced to a skin electrode. We paced 10 of 10 right heart cardiac catheterization, intra- and postoperative surgery patients by methods 1 and 2, and 4 of 4 left heart catheterization patients by method 3. Thresholds (mean +/- SEM) for guide wire pacing were: right ventricle 1.52 +/- 0.4 mA; left ventricle 1.33 +/- 0.1 mA. Guide wire pacing is rapid, reliable, and requires little operator skill. Our indications for guide wire pacing are: 1) emergency right ventricular pacing in operative or intensive care unit patients with unexpected bradyarrhythmias who have an indwelling pulmonary artery catheter; and 2) emergency left ventricular pacing in left heart cardiac catheterization patients with contrast-induced bradyarrhythmias.

Bradycardia↗

Hemodynamic effects of calcium chloride in adults with regurgitant valve lesions.

We evaluated the hemodynamic effects of 7 mg/kg intravenous calcium chloride (CaCl2) or placebo in 20 adults with regurgitant aortic and/or mitral valves before and after induction of anesthesia with fentanyl (50 micrograms/kg), followed by pancuronium (0.1 mg/kg) and 100% oxygen. CaCl2 produced no changes in mean systemic, pulmonary arterial, central venous, or pulmonary capillary wedge pressures or vascular resistances before or after induction of anesthesia. A significant increase in left ventricular stroke work index was seen 1 min after CaCl2 was administered after induction of anesthesia (from 31.29 +/- 3.00 to 37.44 +/- 3.81 g X m X M-2). Before induction, CaCl2 decreased heart rate from 93.9 +/- 9.6 to 85.2 +/- 8.7 beats/min (statistically significant 2.5 and 10 min after CaCl2) and after induction from 104.6 +/- 8.4 to 89.3 +/- 7.5 (significant at 1, 2.5, 5, and 10 min). These results suggest that CaCl2 is associated with an immediate increase in ventricular performance and that the subsequent decrease in heart rate is not sufficient to contraindicate use of CaCl2 as an inotrope in patients with chronic valvular regurgitation. The effects of CaCl2 injection in man on pulmonary shunt fraction (Qs/Qt) have not been described previously. We found no change in Qs/Qt, suggesting that CaCl2 has no direct effect on distribution of pulmonary blood flow.

Aortic Valve Insufficiency↗

Dissociation of the site of origin from the site of cryo-termination of ventricular tachycardia.

We performed conventional electrogram mapping and cryomapping in dogs with one-week-old experimentally-induced myocardial infarctions and programmed stimulation-induced sustained ventricular tachycardias to assess whether there is a correlation between the "site of origin" and site of cryo-termination of ventricular tachycardia (VT). Electrogram maps showed that 4 of 8 induced sustained VTs were due to macro- and 4 of 8 to microre-entry. Local cooling of the site of origin terminated 4 of 4 microre-entrant VTs, but only 1 of 4 macrore-entrant VTs. In the other 3 macrore-entrant VTs, the sites of cryo-termination were 2, 2.5, and 4 cm distant from the sites of origin. In contrast, cooling of the mid-to-late diastolic portions of the re-entry loops terminated all 8 VTs. These data demonstrate a dissociation of the site of origin from the site of cryo-termination of macrore-entrant VT.

Animals↗

Effects of varying post-KR intervals upon children' motor performance.

An experiment using post-KR interval methodology was designed to investigate the developmental relationship of age and processing speed regarding performance on a ballistic linear slide task. The hypothesis drawn from the developmental literature was that, given a short time for processing information, younger children should perform less efficiently than older children and adults. However, an increase in processing time should result in performances being more similar. Subjects in the experiment were 90 female children equally divided among 7 and 11-yr-olds and adults. Within age, subjects were randomly assigned to one of three post-KR interval groups: 3, 6, and 12 sec. Conclusions support the processing deficits hypotheses of Chi (1976): given enough time to process KR, the children's performance was not significantly different from the performance of adults.

Clinical Trial↗

Herpes zoster in patients with systemic lupus erythematosus.

In the context of prospective trials of immunosuppressive drugs in systemic lupus erythematosus (SLE) nephritis, 83 patients were studied with regard to development of herpes zoster. Herpes zoster was found to occur with high frequency (21%) in patients with SLE nephritis treated with immunosuppressive agents. The course of herpes zoster was benign: no deaths occurred and only 2 of the 18 patients developed generalized disease, which resolved without sequelae. Specific antiviral therapy was not necessary and there appears to be no need to decrease immunosuppressive medications. Zoster occurred when the SLE was relatively inactive and did not exacerbate the SLE. No statistical difference in the incidence of zoster was found among the patient groups treated with different immunosuppressive regimens.

Adolescent↗

Presence of functional NMDA receptors in a human neuroblastoma cell line.

Data are presented that provide convincing evidence for the expression of structurally normal and functional NMDA receptors by acetylcholine-producing human LA-N-2 neuroblastoma cells in culture. Reverse transcription and polymerase chain reaction (RT-PCR), followed by cloning and DNA sequencing, revealed the presence in these cells of mRNA representing the key subunit, NMDAR1, of the receptor. This mRNA was further demonstrated by Northern analysis to be the same size as that described for human neurons. The neutral red cytotoxicity assay was utilized to examine the influence on these neuroblastoma cells of a 48-h incubation with either L-glutamic acid or the specific NMDA agonist N-phthalamoyl-L-glutamic acid (NPG). Cell cytotoxicity was shown by this assay to be increased through incubation with glutamate at 1 and 10 mM by 27 and 37%, and through incubation with NPG at 0.1 and 1 mM by 28 and 46%. A possible mechanism of these toxic effects was further evaluated using the whole-cell configuration of the patch-clamp technique and the specific NMDA agonists (+/-)1-aminocyclobutane-cis-1,3-dicarboxylic acid (ACDA) and NPG. Using this procedure, a voltage-dependent tetrodotoxin-sensitive inward sodium current was found to be increased (x 1.5) by L-glutamic acid and by both NMDA agonists in the presence of glycine. Another voltage-gated inward current, probably carried by calcium ions, was increased three- to fourfold. Hence, these glutamate activities observed in human LA-N-2 neuroblastoma cells appear to occur through the activation of functional NMDA receptors in much the same way as reported for neurons, and both glutamate and NMDA agonists can be toxic to these neuroblastoma cells. Our findings, therefore, suggest this cell line will provide a model suitable for investigating the mechanisms of NMDA-related long-term potentiation (LTP) in neurons and of the NMDA-related neurotoxic effects of glutamate in disease states that involve a reduction in cholinergic function.

Blotting, Northern↗