Comparison of polysomnography with ResCare Autoset in the diagnosis of the sleep apnoea/hypopnoea syndrome

BACKGROUND: Increasing referral numbers make the development of simplified accurate methods of diagnosing the sleep apnoea/hypopnoea syndrome highly desirable. The accuracy of one such system--the ResCare Autoset--has been examined. METHODS: Thirty one consecutive patients assessed by polysomnography had simultaneous monitoring of their respiratory pattern using the Autoset system. The Autoset detects episodes of flattening of the flow/time profile using nasal cannulae. RESULTS: There was a good correlation (r = 0.85) between the number of apnoeas+hypopnoeas/hour in bed recorded using polysomnography and the Autoset system. The median difference in such events was 3.1 (95% confidence interval 8.4 to -1.6)/hour in bed. In two patients the Autoset scored 70 apnoeas+hypopnoeas/hour in bed compared with 34 apnoeas+hypopnoeas with 35 arousals/hour in bed by polysomnography; however, this did not alter the diagnostic category of either patient. Autoset gave a sensitivity of 100%, specificity of 92%, positive predictive value of 92%, and negative predictive value of 100%, which was better than oximetry alone. A sleep study using the Autoset system costs 14 pounds compared with 126 pounds for polysomnography. CONCLUSIONS: The Autoset is clinically useful for diagnosing the sleep apnoea/hypopnoea syndrome.     

The fetoplacental pressor effects of low-dose acetylsalicylic acid and angiotensin II in the ex vivo cotyledon model

OBJECTIVE: Our purpose was to investigate perfusion pressure changes ex vivo induced by angiotensin II on fetoplacental vasculature pretreated with low-dose acetylsalicylic acid. STUDY DESIGN: Two cotyledons from each of 12 placentas were perfused. The intervillous space of one cotyledon was infused with acetylsalicylic acid (5 x 10(-5) mol/L) similar to the serum concentration of women receiving daily low-dose aspirin therapy (60 to 81 mg). The control cotyledon was infused with an equivalent amount of normal saline solution. Two doses of angiotensin II, 1 x 10(-11.5) and 1 x 10(-10) moles, were injected as boluses into the chorionic arteries of each cotyledon. A 3 x 10(-7) mole dose of angiotensin II was also injected into the intervillous space. Statistical analysis was performed with analysis of variance, and results are expressed as mean pressure change in millimeters of mercury +/- SEM. RESULTS: Perfusion pressure response did not vary between cotyledons pretreated with acetylsalicylic acid and control cotyledons when 3 x 10(-7) moles of angiotensin II was injected into the intervillous space (8.0 +/- 1.9 mm Hg vs 9.8 +/- 1.6 mm Hg, p = 0.59). There were no differences between cotyledons in pressure response to 1 x 10(-11.5) moles of angiotensin II injected into the fetal circuit (5.9 +/- 0.8 mm Hg vs 6.7 +/- 0.9 mm Hg, p = 0.51). However, in the cotyledons pretreated with acetylsalicylic acid there was a decrease in the pressor response to 1 x 10(-10) moles of angiotensin II (14.1 +/- 1.4 mm Hg vs 21.5 +/- 3.3 mm Hg, p = 0.05). CONCLUSIONS: Low-dose aspirin infused into the intervillous space decreases vasoconstriction elicited by angiotensin II in the fetoplacental compartment. This suggests that maternal low-dose aspirin therapy has effects in the fetoplacental circulation in addition to its effects in the maternal circulation.     

Analysis of the interactions of SDZ PSC 833 ([3'-keto-Bmt1]-Val2]-Cyclosporine), a multidrug resistance modulator, with P-glycoprotein

Multidrug resistance (MDR) is considered to be an important impediment to the effective treatment of cancer. P-glycoprotein, the drug efflux pump that mediates this resistance, can be inhibited by a wide variety of pharmacological agents, resulting in the circumvention of the MDR phenotype. SDZ PSC 833 ([3'-keto-Bmt1]-Val2]-cyclosporine), a nonimmunosuppressive cyclosporine D derivative, was identified to be a potent MDR modulator (Gaveriaux et al. J. Cell Pharmacol. 2:225-234; 1991). In this study, the interactions of P-glycoprotein with two cyclosporine derivatives, SDZ PSC 833 and cyclosporine A (CsA, Sandimmune), were analyzed. SDZ PSC 833 enhanced the sensitivity of the MDR cells to anticancer drugs by increasing the accumulation and inhibiting the efflux of cytotoxic agents from resistant cells more efficiently than CsA. The two cyclosporine analogs competed with the labeling of P-glycoprotein by a photoactive cyclosporine derivative. In addition, membrane vesicles derived from resistant cells bound SDZ PSC 833. However, CsA was transported by P-glycoprotein, whereas SDZ PSC 833 was not actively transported. This resulted in a prolonged inhibitory effect by SDZ PSC 833. The studies suggest that the binding of SDZ PSC 833 to P-glycoprotein in the absence of its transport from MDR cells mediated its high potency as an MDR reversing agent. In addition, the comparison of the two cyclosporine analogs indicated that limited chemical modifications of MDR reversing agents can affect their potential to inhibit P-glycoprotein function.     

Cervical exploration for primary hyperparathyroidism--A 25 year experience

Parathyroidectomy should be considered in every patient with hypercalcaemia and primary hyperparathyroidism even if the symptoms are vague. Cervical exploration is a safe operation with very satisfactory results. Our experience in 214 patients over 25 years shows permanent postoperative normocalcaemia in 95% of cases with a complication rate of 2.8%. All patients with primary HPT, regardless of age or the severity of symptoms should be candidates for cervical exploration.     

Flow versus uptake comparisons of thallium-201 with technetium-99m perfusion tracers in a canine model of myocardial ischemia

We investigated the myocardial flow kinetics of six putative radioperfusion agents (99mTc-Q3, 99mTc-Q4, 99mTc-Q12, 99mTc-sestamibi, 99mTc-tetrofosmin and 99mTcN-NOET) and 201Tl in a canine model of myocardial ischemia with pharmacologic coronary artery vasodilation. METHODS: In 31 open-chest dogs with acute coronary occlusion, dipyridamole (approximately 0.56 mg/kg) was infused intravenously, followed by a perfusion tracer injection and radioactive microspheres for myocardial blood flow (MBF) measurement. The paired data were normalized using three techniques; average, normal or maximum myocardial tracer activity and MBF. RESULTS: The upper limit of MBF obtained for the group of tracers ranged from 4.2 ml/min/g to 8.2 ml/min/g. There was a statistically significant (p < 0.0001) linear correlation (r = 0.87-0.98) between the normalized myocardial activity and the normalized MBF values of each of the tracers. The slope of the curve normalized by average for 201Tl (0.83) was greater than those for the 99mTc tracers, and the intercept (0.07) was lower than those for the 99mTc tracers. Slopes and intercepts for the 99mTc agents were as follows: 99mTc-Q3, 0.81 and 0.18; 99mTc-Q4, 0.61 and 0.41; 99mTc-Q12, 0.63 and 0.39; 99mTc-sestamibi, 0.62 and 0.34; 99mTc-tetrofosmin, 0.68 and 0.32; and 99mTcN-NOET, 0.71 and 0.29, respectively. CONCLUSION: In an anesthetized open-chest canine model of regional myocardial ischemia with dipyridamole induced hyperemia, 201Tl shows a more ideal relationship between tracer uptake and MBF than do the 99mTc-based agents. Of the various 99mTc-based imaging agents studied, the myocardial flow kinetics of 99mTc-Q3 appear to be closest to ideal. This relationship is maintained regardless of the normalization technique used. This may, in theory, imply a higher sensitivity in discerning ischemic from normal myocardium and a role in diagnostic nuclear imaging for 99mTc-Q3.     

Angiotensin II type I receptor polymorphism in African Americans lower frequency of the C1166 variant

The C1166 variant, an A to C substitution polymorphism at the 1166 position of the angiotensin II type I (AT1) receptor, has been previously associated with hypertension in Caucasians. This study determines the frequency of the C1166 variant in an African American population. Normotensive African American (n = 99) and Caucasian (n = 100) subjects were genotyped to determine the frequency of the C1166 variant. This study establishes the frequency of the C1166 variant in African Americans (0.05 +/- 0.01) and demonstrates a significantly lower frequency in African Americans compared with Caucasians (0.05 vs. 0.25, respectively, chi 2 = 30.7, p < < 0.001, 1 df).     

Nicotinic and muscarinic cholinergic receptor binding in the human hippocampal formation during development and aging

High-affinity nicotine, alpha-bungarotoxin (alpha BT) and muscarinic receptor binding was measured in the human hippocampal formation in a series of 57 cases aged between 24 weeks gestation and 100 years. Changes in nicotine receptor binding during development and aging were more striking than differences in alpha BT and muscarinic binding. Nicotine binding was higher at the late foetal stage than at any other subsequent time in all areas investigated. In the hippocampus a fall in binding then occurred within the first six months of life, with little or no subsequent fall during aging, whereas in the entorhinal cortex and the presubiculum the major loss of nicotine binding occurred after the fourth decade. alpha BT binding was significantly elevated in the CA 1 region, but in no other region of the hippocampus, in the late foetus, and there was also a fall in alpha BT binding in the entorhinal cortex during aging from the second decade. The modest changes in total muscarinic binding, which appeared to reflect those in M1 and M3 + 4 rather than M2 binding, were a rise in the entorhinal cortex between the foetal stage and childhood and a tendency for receptors to fall with age in the hippocampus and subicular complex. These findings implicate mechanisms controlling the expression of nicotinic receptors to a greater extent than muscarinic receptors in postnatal development and aging in the human hippocampus.     

Outcomes of hand surgery. British Society for Surgery of the Hand

The findings are presented of a conference on Outcomes of Hand Surgery organized by the audit committee of British Society for Surgery of the Hand in 1993. Measures of outcome in terms of movement, power, sensibility, pain, activities of daily living, complications and patient satisfaction are considered, and an example of a patient evaluation measure given as an appendix.