Patient characteristics associated with differences in patients' evaluation of their general practitioner

Background  

Knowledge of the extent to which patient characteristics are systematically associated with variation in patient evaluations will enable us to adjust for differences between practice populations and thereby compare GPs. Whether this is appropriate depends on the purpose for which the patient evaluation was conducted. Associations between evaluations and patient characteristics may reflect gaps in the quality of care or may be due to inherent characteristics of the patients. This study aimed to determine such associations in a setting with a comprehensive list system and gate-keeping.     

Cerebral blood flow in migraine with aura.

Pathognomonic changes in regional cerebral blood flow (rCBF) have gradually been described during the last decade. They support spreading cortical depression as the mechanism underlying the migraine aura but are not the direct cause of pain since they are absent in migraine without aura and are present in migraine aura without pain. Dilatation of intra- and extracranial arteries, on the other hand, takes place in both forms of migraine and seem closely associated to the pain. Dilatation and perivascular nociceptor sensitization may, very likely, be caused by neuropeptides and monoamines released from perivascular nerves and/or mast cells.     

Characterization of the elastase inhibitor properties of alpha-crystallin and the water-insoluble fraction from bovine lens.

Alpha-crystallin exhibits variable inhibition of several members of the chymotrypsin family of proteinases. Complete inhibition of elastase was obtained by the addition of either alpha-crystallin or a sonicated preparation of the water-insoluble fraction from bovine lens. Little or no inhibition was seen, however, with either beta-crystallin or bovine serum albumin under the same conditions. Complete binding of elastase was demonstrated by Sephadex G-100 gel filtration chromatography, and a direct correlation between binding and inhibition was obtained. This observation permitted us to do a Scatchard analysis of the inhibition data. Scatchard plots for the binding of elastase gave a biphasic response suggesting two separate binding sites. These sites had Kd values of 15 and 40 nM for alpha-crystallin and 6 and 42 nM for the bovine water-insoluble fraction. Similarly, a Dixon plot exhibited a Ki value of 3 nM and was consistent with non-competitive inhibition. One mole of alpha-crystallin (8 x 10(5) Da), or an equivalent amount of water-insoluble protein, bound from 13 to 19 mol of elastase which were about equally divided between the higher and lower affinity sites. Saturation studies confirmed 20 and 16 elastase binding sites per 8 x 10(5) Da for alpha-crystallin and water-insoluble protein, respectively. DFP-elastase was capable of binding to alpha-crystallin suggesting that a proteolytic cleavage was not required for complex formation. Stability measurements showed a linear return to 60% of the original activity over a 30-min period. Therefore, the interaction between elastase and alpha-crystallin resembles that of a heterologous protease:inhibitor complex in both binding and stability.     

Effect of histamine on regional cerebral blood flow in man

Regional cerebral blood flow (rCBF) was measured using the intra-arterial ¹³³Xe technique in 35 or 256 areas of a hemisphere. In seven patients rCBF was measured in the resting state and following intracarotid (i.c.) infusion of histamine 10–50 μg/min. In four patients histamine was infused intravenously in a dose of 25–40 μg/min. Histamine caused no significant change in mean arterial blood pressure or arterial PCO₂. There was no significant change in mean hemispheric blood flow during i.v. or i.c. histamine infusion. No change in the regional distribution of hemispheric blood flow was observed. Experimental histamine headache is most likely of extracranial origin.     

Current determination of lithium-induced minimum sodium requirement in rats

Lithium administration raises the minimum sodium requirement of the organism. Lithium treated-rats drink spontaneously a hypertonic sodium chloride solution and thereby protect themselves against the toxic effects of lithium. In the present paper it was studied whether the consumption of sodium chloride can be used as a quantitative measure of the sodium requirement. Rats given different amounts of lithium with food for about 2 months were given free access to water and a 0.46 M NaCl solution, and the 24-h intake of the latter was followed. It was found that the consumption of hypertonic sodium chloride increased with the lithium dosage and the serum lithium level. The consumption showed the following characteristics: (a) It was sufficient to prevent death from lithium poisoning. (b) When access to hypertonic sodium chloride was discontinued for 48 h, the rats lost body weight; the body weight was reestablished within 1 h when the rats again had access to sodium chloride solution. (c) When sufficient amounts of sodium were given with the food, the lithium-treated rats drank no more sodium chloride solution than did the control rats. (d) When lithium administration was discontinued, the consumption of sodium chloride solution fell within 10 days to the control level. (e) The lithium-treated rats developed polyuria, but this was not the cause of the extra intake of sodium chloride. (f) The lithium-treated rats did not drink more of the hypertonic sodium chloride solution than was necessary to cover the minimum sodium requirement. The results indicate that the intake of hypertonic sodium chloride solution can, in fact, be used as a measure of the minimum sodium requirement in lithium-treated rats.     

The supra-additive natriuretic effect addition of bendroflumethiazide and bumetanide in congestive heart failure: Permutation trial tests in patients in long-term treatment with bumetanide

The additive natriuretic effect of a single dose of bendroflumethiazide, 5 mg., has been studied in patients with advanced congestive heart failure in long-term treatment with bumetanide, 4 mg., daily. Three permutation trial tests were performed including six patients each. In the first trial, the response to supplementary bendroflumethiazide, 5 mg., was definitely superior to that of additional bumetanide, 4 mg., in terms of renal output of sodium, chloride, potassium, water, and osmolal clearance. In the second trial, a similar pattern was found in patients receiving a combination of bumetanide, 4 mg., and spironolactone, 100 mg., daily. The third trial compared the effects of bendroflumethiazide, 5 mg., plus bumetanide, 4 mg.; of bendroflumethiazide, 5 mg.; and of bumetanide, 4 mg. In terms of natriuresis and chloruresis, the response to the combination of two drugs was significantly larger than the sum of the effects of other treatments.It is concluded that the combined effects of the drugs represent a supra-additive effect addition for sodium and chloride. A tentative explanation of the mechanism of interaction in terms of inhibition of renal tubular sodium transport is given.Since the combined effects of the two drugs, independent of supplementary spironolactone, involve a tendency to development of hypokalemia, hypochloremia, and alkalosis, it is recommended that supplementary use of bendroflumethiazide in this setting is combined with the administration of potassium chloride or potassium-saving diuretics.