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Biomedical subjects

K Simpson

Publications and source records attributed to K Simpson.

At least 37 records · Page 2Linked to original sources
PubMed1987

Ultrafiltration in diuretic-resistant cardiac failure.

Ultrafiltration was performed in 13 patients with diuretic-resistant cardiac failure. All patients had severely distressing peripheral edema and ultrafiltration was successfully completed in 12 patients, all of whom sustained symptomatic improvement. The volume of fluid removed ranged from 3.7 to 23 L, mean 11.8 L. Weight reduction produced by ultrafiltration continued over the following week, indicating an improved response to diuretic therapy. Ultrafiltration is an effective therapeutic intervention in the management of a small but well-defined group of patients with diuretic-resistant cardiac failure.

Aged↗
PubMed1987

Systemic and regional hemodynamic effect of acute magnesium administration in the normotensive and hypertensive state.

Recent interest has focused on the role that Mg2+ may play in blood pressure (BP) regulation and in hypertension. The acute effect of intravenous Mg2+ as well as vehicle administration on systemic and regional hemodynamics was determined in both normotensive rats and in rats made hypertensive by uninephrectomy followed by deoxycorticosterone acetate and salt excess (DOCA-salt). Systemic and regional hemodynamics were determined by the radioactive microsphere method in the conscious and unrestrained rat prior to and 1 h following either Mg2+ or vehicle administration. Mg2+ administration significantly increased serum Mg2+ levels in both the normotensive and DOCA-salt hypertensive rats (1.4 +/- 0.02 to 3.5 +/- 0.04 and 1.7 +/- 0.06 to 4.9 +/- 0.4 mEq/l, respectively, both p less than 0.01). The DOCA-salt rats had a significantly greater baseline mean BP, total peripheral resistance (TPR), and heart rate (HR), when compared to the normotensive rats. In the normotensive rats, neither Mg2+ or vehicle administration had any effect on either mean BP or HR. In the DOCA-salt hypertensive rats, vehicle administration had no effect on any systemic hemodynamic parameter. However, in marked contrast, Mg2+ administration significantly decreased mean BP, HR and TPR while not changing cardiac output or index. In both the normotensive and DOCA-salt hypertensive rats vehicle administration did not result in any significant regional organ vascular resistance changes. However, in the normotensive rats, Mg2+ administration significantly decreased vascular resistance in the heart and in the DOCA-salt hypertensive rats Mg2+ administration significantly decreased vascular resistance in the heart, muscle and skin while increasing vascular resistance in the stomach. In conclusion, acute Mg2+ administration significantly decreases blood pressure by peripheral vasodilation in DOCA-salt hypertensive but not in normotensive rats. In addition, acute Mg2+ administration results in a redistribution of blood flow to the heart in both the hypertensive and normotensive state as well as also possibly to the kidney and brain in the hypertensive state. The antihypertensive effect of Mg2+ in the DOCA-salt hypertensive rats as well as the prominent coronary vasodilation seen in both the normotensive and hypertensive rats may have important clinical implications.

Animals↗
PubMed1986

Ultrafiltration in the management of refractory congestive heart failure.

Ultrafiltration was performed in nine patients with congestive cardiac failure that was refractory to conventional medical treatment. A mean of 12 X 7 litres of fluid was removed, and there was a sustained symptomatic improvement in all patients. Weight loss continued after ultrafiltration and a sustained increase in serum sodium concentration was also noted. A transient fall in right atrial pressure was seen only at four hours after ultrafiltration. No adverse haemodynamic effects were seen four and eighteen hours after fluid removal. Intracardiac dimensions measured by echocardiography remained unchanged. Ultrafiltration can be used to relieve symptoms in patients with refractory congestive heart failure and gross oedema.

Blood Pressure↗
PubMed1986

A case of Fryns syndrome.

A case of Fryns syndrome is presented. Characteristic features of this lethal autosomal recessive disorder include corneal clouding, camptodactyly with hypoplastic nails, and abnormalities of the diaphragm.

Abnormalities, Multiple↗
PubMed1986

Hemodialysis-related porphyria cutanea tarda--treatment failure with charcoal hemoperfusion.

A 56-yr-old man presented with a photosensitive bullous dermatosis 1 yr after commencing hemodialysis. Urinary porphyrin levels were normal and fecal porphyrin levels only minimally increased, but the plasma uroporphyrin concentration was markedly elevated, being higher than that normally occurring in porphyria cutanea tarda. The high plasma uroporphyrin level was thought to result from the combined effects of increased porphyrin production and failure of adequate clearance by hemodialysis. Chronic alcohol ingestion, methyldopa therapy and elevated iron and aluminum levels may have contributed to the porphyrin overproduction. Charcoal hemoperfusion proved unhelpful in lowering the plasma uroporphyrin concentration.

Charcoal↗
PubMed1985

Authority and responsibility delegation predicts quality of care.

This study, conducted in acute care hospitals, supports and expands previous findings that delegation of responsibility and authority in the nursing service hierarchy is related to known factors affecting quality of patient care. Quality health care is improved if staff nurses are given autonomy and are expected to function at the level for which they have been prepared.

Absenteeism↗
PubMed1983

Shape determinations of ribosomal proteins in situ.

Ribosomes are heterogeneous for neutrons because RNA and proteins have different neutron-scattering-length densities. This heterogeneity is an obstacle to the shape determination of single ribosomal components within the ribosome. Therefore, we homogenized (matched) the neutron-scattering-length densities of RNA and proteins. 23S and 5S RNA from the large ribosomal subunit were isolated from cells grown in a medium containing 76% 2H2O. The total protein fraction of the large ribosomal subunit was isolated from cells grown in a medium containing 84% 2H2O. When these constituents were used for total reconstitution of 50S subunits, neutron scattering measurements of the reconstituted particles revealed excellent matching near 100% 2H2O. A three-step reconstitution procedure was developed that allowed the reconstitution of 50S subunits from deuterated RNA, deuterated total (i.e., unfractionated) proteins, and single protonated proteins. The reconstituted particles contain one protonated protein or two in a matched ribosomal matrix and were used for shape determination or distance measurement of mass centers of gravity, respectively. The signal/noise ratio is high enough to allow measurement in solutions containing nearly 100% 2H2O at concentrations of only 300-500 A260 nm units/ml. Our experiments have proved the feasibility of our biochemical strategy. The shape determinations of ribosomal proteins in situ gave radii of gyration for L1, L3, L4, and L23 of 26 +/- 2, 22 +/- 2, 20 +/- 2, and 13 +/- 2 A, respectively.

Escherichia coli↗
PubMed1979

Use of reversed-phase high-performance liquid chromatographic analysis for the determination of provitamin A carotenes in tomatoes.

The usual methods for provitamin A evaluation of foods convert the total pigment amount, determined spectrophotometrically, into vitamin A units. Since the totally inactive lycopene is the major carotenoid in the tomato, such readings result in erroneously high provitamin A values. In view of the recent development of chemically bonded, reversed-phase, microparticulate packings and their use in high-performance liquid chromatography which combines highly accurate and reproducible resolution with the speed and ease of operation, a new method using such a system was developed to isolate carotenoid pigments from tomato samples. A 15-min column separation was thus achieved, dramatically decreasing the analysis time of the classical open column chromatographic procedures, which often result in unresolved and altered fractions due to long-term exposure to oxygen, light, solvents and sometimes adsorbent. beta-Carotene and lycopene were determined and quantitated in six tomato samples. beta-Carotene, 100% vitamin A-active, was expressed in International Units of vitamin A. The newly developed method gives a more reliable evaluation of the fruit potency in vitamin A than the methods of the Association of Official Analytical Chemists currently used for food composition tables.

Carotenoids↗
PubMed1975

Neonatal respiratory failure due to myotonic dystrophy.

Myotonic dystrophy should be included in the differential diagnosis of neonatal respiratory failure accompanied by hypotonia. The effect of this disorder in an infant who died from it 49 hours after birth is described, and the importance of examining the mother of a possible case is emphasized.

Humans↗