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Biomedical subjects

J Butler

Publications and source records attributed to J Butler.

At least 289 records · Page 16Linked to original sources
PubMed1981

Effects of positive end-expiratory pressure on intracranial pressure in dogs with intracranial hypertension.

Positive end-expiratory pressure (PEEP) is used to improve oxygenation in patients with the adult respiratory distress syndrome. Nevertheless, this treatment may increase intracranial pressure (ICP) and be detrimental to certain neurosurgical patients. This clinical situation was simulated by administering PEEP to dogs with normal and elevated ICP. Increases in PEEP increased ICP in all animals. However, the presence of intracranial hypertension diminished the increase in ICP seen at a given level of PEEP. Cerebral perfusion pressure also fell less in the presence of intracranial hypertension than it did in the absence, although in the former situation cerebral perfusion pressure was at the lower limits of the range of cerebral autoregulation. These findings suggest that PEEP is no more detrimental to patients with elevated ICP than it is to patients whose ICP is normal, assuming that their cerebral autoregulation is not impaired.

Animals↗
PubMed1981

Thymic mast cell deficiency in avian muscular dystrophy.

In animals with hereditary muscular dystrophy there are thymic abnormalities which may be of etiological significance in the dystrophic process. This study investigated mast cell number and histamine levels in the thymus of normal and dystrophic chickens. For comparison, other lymphoid tissues, namely the spleen and the bursa of Fabricius, and non-lymphoid tissues including the comb and pectoralis major muscle, were similarly studied. Our results show that the thymus of dystrophic adult birds has a deficiency in both mast cell number and histamine content. In the bursa of Fabricius of dystrophic birds a significant elevation in histamine content (microgram/g) was attributed to the abnormally small size of this organ, rather than to an absolute mast cell increase. The deficiency in thymic mast cell number in dystrophic chickens may be significant in the postulated abnormal thymus-muscle interaction of the dystrophic process.

Animals↗
PubMed1980

New developments in cardiopulmonary resuscitation.

The traditional concept of cardiopulmonary resuscitation (CPR) is that the heart is squeezed between the sternum and the spine during external cardiac massage to create a pressure gradient that forces blood from the heart to the periphery. Although the heart may actually be squeezed in some persons by this maneuver, a newer view of CPR holds that closed-chest compression produces a generalized rise in intrathoracic pressure that is applied to the pulmonary vascular bed as well as the heart. Thus, the heart does not serve primarily as a pump during external cardiac massage but instead acts as a conduit for blood from the lungs. Furthermore, flow into extrathoracic vessels depends on their tendency to remain open or to collapse: forward flow occurs across the head during CPR because a pressure gradient is developed between the carotid artery and the more compressible jugular vein. These ideas have potential clinical implications and greatly increase our understanding of the physiology of CPR.

Coronary Circulation↗
PubMed1980

Formation of super-reduced Chromatium high-potential iron--sulphur protein in aqueous solution by pulse radiolysis.

Both the oxidized and reduced forms of Hipip (high-potential iron--sulphur protein) are reduced (approx. 30% yields) by eaq.- in a single-stage process, rate constants 1.7 x 10(10) and 1.8 x 10(10) M-1 . s-1 respectively, at 25 degrees C, pH 7.0 (5 mM-phosphate). Super-reduced Hipip, which is formed in the latter case, has a spectrum which closely resembles that of reduced ferredoxin, i.e. Fe4S4 (SR)4(3-) clusters. The spectrum is stable over 2 s periods investigated. Super-reduced Hipip is reoxidized with O2, rate constant 4.8 x 10(6) M-1 . s-1 at 25 degrees C.

Chromatium↗
PubMed1980

Renal allografts retained in situ after failure.

Twenty-four renal allografts functioning up to six years from the date of transplantation were retained in situ from four days to five years following return of the patient to hemodialysis. Fifteen of the 24 kidneys were removed for specific indications within four days to ten months. The reasons for allograft nephrectomy included fever, hematuria, graft pain and tenderness, and severe hypertension. Nine patients remained asymptomatic with grafts retained three months to five years (median, two years) following return to hemodialysis. It appears safe to retain nonfunctioning grafts in asymptomatic patients, thereby avoiding an unnecessary operation when failure is due to chronic rejection or recurrent glomerulonephritis. Nevertheless, in many patients complications eventually develop for which the allograft will be removed.

Adolescent↗
PubMed1980

Response of renal allograft recipients to pneumococcal vaccine.

Antibody responses to pneumococcal polysaccharide vaccine were compared in a control group of 17 normal adults and in a group of 27 adult patients with stable renal function (serum creatinine 0.8--2.1 mg/dl) seven months to nine years following renal transplantation. Using the indirect hemagglutination technique, antibody titers to 13 of the 14 capsular antigens contained in the vaccine were determined for each patient just prior to and again three weeks following immunization. There was no significant difference between the two groups in the proportion of patients responding with a fourfold rise in titer to 12 of the 13 antigens tested. The response rate to antigen type 3 was reduced in the transplant group (p less than 0.05). Mean fold increase in indirect hemagglutination titers was likewise determined for each antigen, and a reduced response in the transplant group was noted only to antigen type 23 (p = 0.037). Immunosuppressed renal allograft recipients appear capable of mounting a nearly normal antibody response to pneumococcal vaccine.

Adult↗
PubMed1980

Lung inflation can cause pulmonary edema in zone I of in situ dog lungs.

We investigated whether increases in lung water can occur due to lung inflation in zone I when alveolar vessels are collapsed. Static left lower lobe alveolar pressure, pulmonary arterial pressure, and pulmonary venous pressure were controlled in living, anesthetized, open-chested dogs. The lobe was inflated with 6% CO2 in air and suspended from a strain gauge, which allowed continual weight recording. The lung was held in zone I conditions. Arterial and venous pressures were equal at either 1 or 5 cmH2O, relative to the base of the 10- to 14-cm-high lobes. Weight changes were measured for 5 min after 5-cmH2O increments of alveolar pressure from 0 or 5 to 30 cmH2O. Lung weight gain due to edema occurred with inflation to alveolar pressures above 10 cmH2O. Greater lung distension resulted in greater rates of weight gain. Weight loss occurred on deflation. The fluid may have leaked from distended extra-alveolar vessels. This mechanism could explain the increased lung water seen with mechanical ventilation and/or positive end-expiratory pressure breathing.

Animals↗
PubMed1980

Study of the effects of hydrocortisone and hydrocortisone 17-butyrate ointments on plasma ACTH levels and Synacthen responses in children with eczema.

This study compares the effects on the hypothalamo-pituitary adrenal (HPA) axis of two dosage schedules of hydrocortisone 17-butyrate and hydrocortisone ointments in 20 children suffering from eczema. Children with moderately extensive eczema received either 30 g of 0.1% hydrocortisone 17-butyrate or 30 g of 1% hydrocortisone ointment weekly for 4 weeks without occlusion. Children with extensive eczema received either 60 g of hydrocortisone 17-butyrate or 60 g of hydrocortisone weekly for 4 weeks. All four groups showed some clinical improvement. Although many of the children appeared to have some impairment of adrenal function prior to entering the trial, no further significant depression of the HPA axis as reflected by the plasma ACTH levels and a 30-min Synacthen test was observed during the trial. On the basis of 4 weeks' treatment, hydrocortisone 17-butyrate did not have a significantly different effect on the HPA axis in children from that of hydrocortisone.

Administration, Topical↗
PubMed1980

Alveolar gas compression in smokers and asthmatics.

To correlate the degree of alveolar gas compression with the severity of airway obstruction, we plotted separately exhaled and plethysmographic maximal-expiratory-flow-volume (MEFV) curves in each of 4 healthy nonsmokers, 4 asymptomatic smokers, and 4 asymptomatic asthmatics. Spirometry, lung volumes, single breath nitrogen plateau (Phase III), and closing volumes (Phase IV) were normal in the smokers and nonsmokers, and there were either normal or showed evidence of mild airway obstruction in the asthmatics. MEFV curves were plotted by using exhaled flow (VE) against exhaled volume (VE), and by using plethysmographic flow (VL) against plethysmographic volume (VL). These curves were utilized to construct isovolume-pressure-flow (IVPF) curves of esophageal pressure (Pes) against VE and against VL for each subject. Differences in the flow (VL minus VE) were calculated from these curves at 75% vital capacity (VC), 50% VC, and 25% VC at the same Pes in all 3 groups. At 75% VC, the mean flow difference in the asthmatic group was significantly higher than in normals (P less than 0.05); at 50% VC, it was significantly higher both in the asthmatics and the smokers (P less than 0.05); at 25% VC, there was no significant difference among the 3 groups. The mean plethysmographic forced vital capacity (FVC) exceeded exhaled FVC in all 3 groups, but the difference was significantly higher in smokers and asthmatics than in nonsmokers (P less than 0.05). These findings suggest that significant alveolar gas compression may occur at 75% VC in mild asthmatics, whereas in smokers it occurs at the middle portion of the VC.

Adult↗