Search PubMed⌕ Search

Biomedical subjects

K Watson

Publications and source records attributed to K Watson.

154 records · Page 9Linked to original sources
PubMed1967

Oxidative phosphorylation and respiratory control in mitochondria from Aspergillus niger.

1. Tightly coupled mitochondria were isolated from Aspergillus niger by using an all-glass homogenizer followed by differential centrifugation. 2. The mitochondria oxidized the common intermediates of the tricarboxylic acid cycle, NADH(2) and the ascorbate-tetramethyl-p-phenylenediamine system. 3. High P/O ratios and control of respiration by ADP were obtained with all substrates tested. The average P/O ratios observed were: 1.5-1.8 with succinate as substrate [respiratory control ratio (RC) 2-4]; 0.8-1.0 with ascorbate-tetramethyl-p-phenylenediamine (RC 1.2-1.5); 1.4-1.8 with NADH(2) (RC 2-3); 2.4-2.8 with alpha-oxoglutarate (RC 3-5). 4. Bovine serum albumin (0.05-0.2%) was essential for tightly coupled respiration to be observed. 5. Coupled oxidation of exogenous NADH(2) was relatively insensitive to rotenone and Amytal. 6. The mitochondria responded to specific inhibitors and uncoupling agents in a manner similar to that of mammalian mitochondria. 7. It was concluded that the isolated mitochondria from A. niger show respiratory properties similar to those reported for intact yeast and mammalian mitochondria.

Adenine Nucleotides↗
PubMedDate not supplied

The effect of graded exercise on cardiac output of the Jarvik-7-70 total artificial heart in humans.

Animal exercise studies have shown a self-regulated change in cardiac output (CO) with the J-7 total artificial heart (TAH). A 49-year-old, 75 kg patient received a J-7-70 TAH as a bridge to transplant. During bicycle exercise, the TAH heart rate, drive pressures, percent systole, and vacuum were unchanged. Cardiac output was measured by analysis of diastolic air exhaust. Mean arterial pressure (MAP) was measured via a radial artery catheter. Daily recordings of hemodynamics were made from TAH day 35 to 56 at rest, cycling with zero resistance, 18 watts resistance, return to zero resistance, and at rest. Values were as follows: baseline MAP, 75.7 +/- 9.7; LCO, 6.4 +/- 0.2; RCO, 6.8 +/- 0.2. For zero watts resistance MAP was 92.2 +/- 7.2*; LCO, 7.1 +/- 0.2*; RCO, 7.8 +/- 0.3*. For eighteen watts resistance MAP was 101.3 +/- 6.2*; LCO, 7.6 +/- 0.3*; RCO, 8.4 +/- 0.4*. For zero watts resistance MAP was 98.5 +/- 4.9*; LCO, 7.2 +/- 0.4*; RCO, 8.0 +/- 0.4*. The postexercise MAP was 86.4 +/- 4.1*; LCO, 6.2 +/- 0.2; RCO, 6.9 +/- 0.2. For all but baseline and postexercise MAPs, the average response was over a 4 minute interval. The starred values were significant compared to baseline p less than 0.05. Exercise resulted in an autoregulated change in TAH CO in man. Increasing the work of exercise produced an increased CO, reflecting changes in venous return. A TAH patient can exercise for more than 30 minutes with an autoregulated CO and no deleterious effects.

Blood Pressure↗
PubMedDate not supplied

Coronary heart disease in African Americans.

African Americans have the highest overall mortality rate from coronary heart disease (CHD) of any ethnic group in the United States, particularly out-of-hospital deaths, and especially at younger ages. Although all of the reasons for the excess CHD mortality among African Americans have not been elucidated, it is clear that there is a high prevalence of certain coronary risk factors, delay in the recognition and treatment of high-risk individuals, and limited access to cardiovascular care. The clinical spectrum of acute and chronic CHD in African Americans is similar to that in whites. However, African Americans have a higher risk of sudden cardiac death and present more often with unstable angina and non-Q-wave myocardial infarction than whites. African Americans have less obstructive coronary artery disease on angiography, but may have a similar or greater total burden of coronary atherosclerosis. Ethnic differences in the clinical manifestations of CHD may be explained largely by the inherent heterogeneity of the coronary syndromes, and the disproportionately high prevalence and severity of hypertension and type 2 diabetes in African Americans. Identification of high-risk individuals for vigorous risk factor modification-especially control of hypertension, regression of left ventricular hypertrophy, control of diabetes, treatment of dyslipidemia, and smoking cessation--is key for successful risk reduction.

Age Factors↗
PubMedDate not supplied

A prospective study of septic complications of endoscopic retrograde cholangiopancreatography.

Prophylactic antibiotics are used in an attempt to avoid the septic complications of endoscopic retrograde cholangiopancreatography (ERCP). We prospectively performed blood cultures and surveyed patients for complications. The aims were first, to determine the incidence of bacteraemia associated with ERCP, second, to assess the incidence of clinical sepsis following the procedure and third, to evaluate the effectiveness of our antibiotic prophylaxis. One hundred and fifty successive patients underwent 179 ERCP. Bacteraemia related to the procedure or the underlying pathology was found in nine procedures (5.2%). Bacteraemias were more likely to complicate therapeutic procedures (P = 0.015), biliary obstruction (P = 0.045) or underlying pathology (P = 0.022). Although 61% of ERCP received antibiotics, 22 septic events occurred. Five bacteraemic patients were septic despite antibiotics. Septic complications were associated with the same factors as bacteraemia. It was concluded that patients with biliary obstruction and undergoing therapeutic endoscopic procedures are at greatest risk of bacteraemia. Single dose prophylactic antibiotics may not prevent sepsis in these patients and longer-acting drugs or repeated dosing may be necessary.

Adolescent↗
PubMedDate not supplied

Severity of violence against women correlates with behavioral problems in their children.

In order to examine the type and severity of violence against women by intimate partners and the associated behavioral problems of their children, 83 abused women were interviewed when they presented to the criminal justice system for protective orders or to file assault charges. Two questionnaires were administered: (a) the 46-item Severity of Violence Against Women Scale (SVAWS) measured threats of abuse and actual physical violence, and (b) the 118-item Child Behavior Checklist (CBCL) measured child behavior problems for children between the ages of 4 and 18.

Adolescent↗
PubMedDate not supplied

A comparison of two grass pollen extracts in the treatment of hay fever.

This trial of hyposensitisation compares the efficacy and safety of an alum absorbed 2-grass extract (Phleum pratense and Dactylis glomerata) with a traditional pyridine extracted alum precipitated 5-grass preparation whose efficacy has been demonstrated previously. 33 patients, (20 Alpare, 13 Allpyral), were entered into the trial which continued for 3 years; in the second year there were 17 Alpare and 11 Allpyral patients, and 13 Alpare and 10 Allpyral in the third year. Patients on Alpare required fewer dosage modifications due to adverse effects, but otherwise the treatments proved comparable. By the end of the second year, all patients achieved a significant increase of grass-specific IgG. There was no increase in total or specific IgE levels. Subjective assessment by both patients and physicians was in favour of Alpare in the first year, and a larger percentage of Alpare patients achieved a symptom-free summer in the second year. Analysis of daily diaries kept by patients during the grass pollen seasons showed that both treatments resulted in decreased use of medication year by year despite increasing pollen counts. We have shown that an extract made in accordance with modern requirements for purification and biological standardisation performed at least, as well as the older proven form of treatment.

Adolescent↗
PubMedDate not supplied

Trouble-free dental local anaesthesia.

Although administration of local anaesthesia in dentistry is generally both safe and effective, problems do occur. This article summarizes the types of problem the dental practitioner may encounter, in the hope that increased awareness will decrease the incidence.

Anesthesia, Dental↗