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S Jones

Publications and source records attributed to S Jones.

At least 577 records · Page 32Linked to original sources
PubMed1985

Accumulation of alveolar surfactant following delivery and ventilation of premature lambs.

We studied the accumulation of surfactant in the alveoli and airways from birth to 10 h of age in 60 lambs delivered prematurely at a mean gestational age of 136 days. The lambs were delivered by cesarean section and ventilated by varying peak inspiratory pressures only to normalize arterial blood gas and pH values. Alveolar surfactant accumulation was measured either by alveolar wash after timed sacrifice or by repetitive sampling of the airways using an isotope dilution technique. The fall in specific activity of phosphatidylcholine with time was measured after the intratracheal administration of either a trace dose of 3H-labeled natural surfactant and synthetic 14C-dipalmitoylphosphatidylcholine (DPPC) at birth or a treatment dose of the same mixture at 5 h of age (about 55 mg of total surfactant lipid/kg body weight). From the change in phosphatidylcholine-specific activities and the quantities and specific activities of phosphatidylcholine measured in alveolar washes, we found that the surfactant pool sizes as estimated by alveolar wash or by the isotope dilution technique were similar. The pool size of alveolar surfactant increased fourfold from birth to 20 min of age and doubled again by 10 h of age. The shape of the curve for the accumulation of alveolar surfactant versus time was independent of the final pool size achieved at 10 h of age. Sonicates of DPPC when mixed with either a trace amount or a treatment dose of natural surfactant were treated by the premature lung in a manner indistinguishable from the phosphatidylcholine associated with natural surfactant.

Animals↗
PubMed1985

The effect of an advanced cardiac life support course on advanced cardiac life support ability.

Thousands of health care providers spend time, money, and energy each year taking the AHA-sponsored ACLS courses, and ACLS-certified health care providers are frequently given greater job responsibility than other health care providers in the same setting. The purpose of this study was to determine the effect of an ACLS course on the ability of health care providers to perform ACLS in a simulated situation. A nonequivalent control group design was used. The sample consisted of 76 health care providers whose job responsibilities included ACLS. The Mega-Code skill station from the ACLS course was used to evaluate ACLS performance. Chi-square analyses showed a significant (p less than 0.05) difference in the posttest pass/fail results of the two groups and a significant (p less than 0.05) difference in the changes from pretest to posttest of the two groups. The research hypotheses were supported, and the researches concluded that the course had a positive effect on the subjects' ACLS ability.

Clinical Competence↗
PubMed1985

The effect of T cell-derived lymphokines on the levels of isotype-specific RNA in normal B cells.

T cell-derived lymphokines, known as B cell differentiation factors (BCDF), play a critical role in the regulation of B cell differentiation. These BCDFs are present in the supernatants (SN) of a long-term alloreactive T cell line, PK 7.1. In this report we present evidence that B cells cultured with lipopolysaccharide (LPS) and BCDFs express increased levels of both the secreted and membrane forms of gamma 1 mRNA. The appearance of mRNA for the membrane form of mu precedes the appearance of mu secreted form mRNA. Approximately 1 day later, appearance of membrane and secreted forms of gamma 3 and gamma 1 can be detected with the membrane forms of both isotypes peaking earlier than the corresponding secreted forms. The mRNAs for both the membrane and secreted forms of gamma 3 are suppressed in the presence of LPS and PK 7.1 SN while LPS alone induces an increase in both. Quantification of newly synthesized nuclear and cytoplasmic RNA for mu, gamma 3, and gamma 1 RNA suggests that PK 7.1 SN down-regulates levels of gamma 3 RNA by decreasing its transcription. In contrast, it may increase level of gamma 1 RNA by effects exerted at the post-transcriptional level. Taken together, these results demonstrate that T cell-derived lymphokines can act on B cells by regulating the levels of nuclear and cytoplasmic RNA specific for gamma 1 and gamma 3.

Animals↗
PubMed1985

Cephalosporins for prophylaxis in operative repair of femoral fractures. Levels in serum, muscle, and hematoma.

We conducted a prospective controlled study of thirty patients who had an open reduction with internal fixation of a closed fracture of the femur. Each patient received cefamandole, cefazolin, or cefoxitin intravenously (twenty-five milligrams per kilogram of body weight) on entry into the operating room. Intraoperatively, samples of blood, muscle, and organizing hematoma were collected for determination of levels of the antimicrobial agent. Throughout the operation, cefazolin was shown to result in significantly higher levels in serum. The mean concentrations in muscle were similar for all three drugs, but the levels in the hematoma were twice as high with cefazolin as with cefamandole or cefoxitin. No correlation was evident between the concentration of any of these antibiotics in the hematoma and the interval between injury and operation.

Adolescent↗
PubMed1984

Reutilization of phosphatidylcholine analogues by the pulmonary surfactant system. The lack of specificity.

Five specific 14C-labelled analogues of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, (L-alpha-DPPC) including 1-palmitoyl-sn-glycero-3-phosphocholine, (L-alpha-lysoPC) and 2,3-dipalmitoyl-sn-glycero-1-phosphocholine (the D isomer of DPPC) were individually mixed with L-alpha-[3H]DPPC and unlabelled natural surfactant isolated from 3-day-old rabbits. The mixtures were injected intratracheally into 3-day-old rabbits which were then killed at preset times up to 72 h after injection. Phosphatidylcholine was isolated from the alveolar wash and from lamellar body fraction from each rabbit and was analyzed for the ratio of 3H-to-14C counts/min. These ratios were plotted against the time the rabbits were killed to determine whether a difference existed in the rates of reutilization of the analogues relative to L-alpha-DPPC. By 60 h L-alpha-lysoPC was reutilized at 42% of the efficiency of the L-alpha-[3H]DPPC with which it was injected. That part of the L-alpha-lyso which was reutilized had been converted to [14C]phosphatidylcholine. Each of the other four analogues was reutilized by the surfactant system as efficiently as L-alpha-DPPC. These results are most consistent with a process of bulk uptake of surfactant from the alveolar space by the Type II cell with subsequent processing for resecretion which involves minimal specificity for molecular structure.

Animals↗
PubMed1984

Family factors in schizophrenic relapse. Replication in California of British research on expressed emotion.

Our study of the emotional atmosphere of the homes of schizophrenic patients in southern California has replicated British findings concerning the influence of the family environment on the course of schizophrenia. As in the British studies, criticism and overinvolvement expressed by a key relative about the patient at the time of the key admission proved to be the best single predictor of symptomatic relapse in the nine months after discharge from the hospital. Replicating the British results, the association between relatives' expressed emotion and relapse was independent of all other variables investigated. Cross-cultural results concerning the prophylactic effects of medication suggest that clinicians should look to the emotional atmosphere in the home for explanations of medication failures.

Adolescent↗
PubMed1984

Signal averaged electrocardiography in infants and children with congenital heart disease.

Forty-four patients with congenital cardiac disease underwent surface averaged electrocardiography using a high resolution purpose built module. Twelve patients had complete transposition of the great vessels, 14 had tetralogy of Fallot, 5 had ventricular septal defects, 6 atrial septal defects, 3 atrioventricular septal defects and 4 patients had miscellaneous non-structural abnormalities. All patients with structural disorders underwent corrective or palliative surgery. The aim of the study was to examine the feasibility of the method and its usefulness in detecting His potentials and delayed potentials in the ST segment. A His potential was recorded in 30 patients (68%) with an amplitude ranging from 1.25 to 8.25 microV. Delayed potentials were recorded in only 1 patient with frequent ventricular premature beats. This technique may be useful in assessing intraventricular conduction times in patients with bundle branch block and/or axis deviation especially those who are at risk from intermittent complete AV block after surgical intervention. Detection of delayed potentials may allow better assessment of post-operative risk of ventricular arrhythmias in patients who have undergone ventricular surgery.

Bundle of His↗
PubMed1984

Emergency transvenous ablation of atrioventricular conduction to control refractory atrial tachycardia.

Three patients were referred for urgent investigation and treatment of refractory arrhythmias. Each patient had failed to respond to antiarrhythmic drugs and in two patients direct current cardioversion was also unsuccessful. Transvenous ablation of atrioventricular conduction was therefore thought appropriate. With a temporary ventricular pacing system in situ, a second electrode was used to record His and atrial electrograms. A 270 watt-second shock was delivered through this lead when the His potential was maximized. The tachycardia was controlled in two patients and the procedure was without deleterious effects.

Bundle of His↗
PubMed1984

Surfactant and pulmonary blood flow distributions following treatment of premature lambs with natural surfactant.

Prematurely delivered lambs were treated with radiolabeled natural surfactant by either tracheal instillation at birth and before the onset of mechanical ventilation, or after 23 +/- 1 (+/- SE) min of mechanical ventilation. Right ventricular blood flow distributions, left ventricular outputs, and left-to-right ductal shunts were measured with radiolabeled microspheres. After sacrifice, the lungs of lambs receiving surfactant at birth inflated uniformly with constant distending pressure while the lungs of lambs treated after a period of ventilation had aerated, partially aerated, and atelectatic areas. All lungs were divided into pieces which were weighed and catalogued as to location. The amount of radiolabeled surfactant and microsphere-associated radioactivity in each piece of lung was quantified. Surfactant was relatively homogenously distributed to pieces of lung from lambs that were treated with surfactant at birth; 48% of lung pieces received amounts of surfactant within +/- 25% of the mean value. Surfactant was preferentially recovered from the aerated pieces of lungs of lambs treated after a period of mechanical ventilation, and the distribution of surfactant to these lungs was very nonhomogeneous. Right ventricular blood flow distributions to the lungs were quite homogeneous in both groups of lambs. However, in 8 of 12 lambs, pulmonary blood flow was preferentially directed away from those pieces of lung that received relatively large amounts of surfactant and toward pieces of lung that received less surfactant. This acute redirection of pulmonary blood flow distribution may result from the local changes in compliances within the lung following surfactant instillation.

Animals↗
PubMed1984

Nominal dysphasia and the severity of senile dementia.

Previous research has shown that nominal dysphasia occurs commonly as a language disorder in senile dementia (Alzheimers' type). This study provides evidence that the degree of nominal dysphasia shown by a patient may be a reliable index of the severity of dementia, as measured by both behavioural and cognitive rating scales.

Aged↗