Percutaneous Myocardial Laser Revascularization

Transmyocardial laser revascularization (TMR) is an experimental procedure for intractable angina that has demonstrated clinical benefit. The majority of patients who had TMR have significant reduction of angina. TMR has been performed exclusively by thoracic and cardiac surgeons using a handhold CO₂ laser device. The development of a prototype percutaneous device that delivers mid-infrared laser energy (Ho:YAG) through a 9Fr coaxial catheter system recently has been reported. The long-term benefits of this percutaneous approach is being defined in the context of the randomized PACIFIC Trial. The initial follow-up suggested significant relief of angina in the majority of treated patients, and the results are likely to be equal or similar to those of surgical TMR. The safety data of percutaneous myocardial revascularization (PMR) with the CardioGenesis system showed exceedingly low morbidity and mortality.     

The Effects of Rate and Rhythm Control on Blood Pressure and Antihypertensive Drug Usage in Patients with Atrial Fibrillation and Hypertension Enrolled in the AFFIRM Trial

AF and HTN in the AFFIRM trial . Introduction: Atrial fibrillation (AF) has been shown to be associated with activation of the renin–angiotensin–aldosterone system, endothelial dysfunction, and increased sympathetic activity, all of which could lead to hypertension (HTN). While the effects of HTN on AF incidence and arrhythmogenesis have been reported, the long‐term effects of AF on blood pressure (BP) remain unknown. We hypothesized that a rate control strategy is associated with an increase in BP and/or antihypertensive drug therapy when compared with a rhythm control strategy in patients with a history of AF and HTN. Methods and Results: Using the intention to treat method, BP readings and the number of antihypertensive medication categories were analyzed over the first year of follow‐up in patients with AF and HTN enrolled in the AFFIRM trial. No clinically significant changes in BP occurred. Medication data were available in 2,876 patients. In the rate control group, 27.8% of patients required a net increase in the number of antihypertensive medications when compared to 18.3% in the rhythm control group (P < 0.001). Furthermore, 27.1% of patients in the rate control group had a net decrease in the number of antihypertensive medications when compared with 41.7% in the rhythm control group (P < 0.001). Conclusions: Our findings suggest that AF could be contributing to BP elevation in patients with a history of HTN and that a rhythm control strategy might result in a decrease in BP in these patients. This hypothesis however, requires future testing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1094‐1098)     

Interpretation of in-vitro thyroid function tests during pregnancy

Summary. In-vitro thyroid function tests are difficult to interpret in pregnancy because of, among other things, the effect of oestrogens on thyroid binding globulin (TBG) concentrations. In an attempt to clarify the position, serum concentrations of total thyroxine (T₄), free T₄, TBG, T₄/TBG ratio, tri-iodothyronine (T₃) and thyroid stimulating hormone (TSH) were measured. Total T₄ and TBG concentrations rose to above the non-pregnant reference range by 20 weeks. The T₄/TBG ratio fell to hypo-thyroid values by 20 weeks but although the free T₄ level was lower in the third trimester compared with values in the first and second trimesters, only a few subjects had hypothyroid values. The TSH values remained unchanged throughout pregnancy. The significance of these changes is discussed and reference ranges for these hormones at each trimester are provided.     

Case report: A patient with primary biliary cirrhosis and autoimmune haemolytic anaemia

Diseases of an autoimmune nature are well recognized in association with primary biliary cirrhosis. Although autoimmune thyroiditis and many rheumatological conditions are well described in primary biliary cirrhosis, autoimmune haematological diseases have been less well reported. We report on a 66 year old North American Indian man with coincident primary biliary cirrhosis and warm antibody haemolytic anaemia. This case report supports the suggestion of an association between autoimmune haemolytic anaemia and primary biliary cirrhosis.     

Anaesthetic management of a neonate with nesidioblastosis

Nesidioblastosis is a disorder which is characterized by autonomous insulin secretion that is not affected by decreases in blood glucose. Patients usually present during the neonatal or infantile period with hypoglycaemia associated with hyperinsulinaemia. Most cases of nesidioblastosis are sporadic; however, familial forms appear to be inherited in an autosomal recessive manner. We discuss the anaesthetic management of a patient with nesidioblastosis who presented for near total pancreatectomy and review the literature pertinent to the anaesthesiologist.     

NMR and X-ray crystallographic studies on cyclic tetrapeptide,cyclo (D-Phe-Pro-Sar-Gly)

The conformation of the synthetic cyclic tetrapeptide cyclo (D-Phe-Pro-Sar-Gly) has been determined in solution using the nuclear magnetic resonance technique and in the crystal state by X-ray crystallography. Results showed that the peptide exhibited two different conformations in solution, conformer 1 having cis-trans-cis-trans peptide bonds and conformer 2 having trans-cis-trans-cis peptide bonds. No intramolecular hydrogen bonds were observed in the structures. The X-ray diffraction studies showed the crystals to be orthorhombic with space group P2₁2₁2₁ with unit-cell dimensions, a = 5.790, b= 10.344, c = 31.446 Å, Z=4, R= 0.104 for 2301 observed reflections. The crystal structure showed only one type of conformer having cis-trans-cis-trans peptide bonds similar to the conformer 1 in solution. © Munksgaard 1996.     

Time course and mechanisms of decreased plasma volume during acute psychological stress and postural change in humans

In this study, we examined the effects of psychological stress on calculated plasma volume, the relationship of these changes to changes in hematologic factors, and the time course of plasma volume changes. Plasma volume changes were assessed using mass densitometry techniques, which measured changes in blood and plasma density. Hematologic and hemodynamic variables were assessed in 40 healthy men and women during a mental arithmetic (math) or benign reading task and during postural change (standing). Results indicated that math and posture change produced a significant decrease in plasma volume (ps < .001) and increases in blood pressure (ps < .001), blood and plasma density (ps < .001), and total plasma protein (p < .001). Correlations were observed between plasma volume changes and changes in systolic (r= .55, p < .0001), diastolic (r= .61, p < .0001), and mean (r= .65, p < .0001) arterial pressure during math; plasma volume and blood pressure returned to baseline within 12 min following the math task. These results suggest that an important mechanism for stress-induced decreases in plasma volume is increased blood pressure leading to increased fluid shifts from the vasculature into the interstitial spaces.     

The preparedness to share injecting equipment: an analysis using vignettes

This paper reports on the use of vignettes to study drug injectors’preparedness to share injecting equipment. Separate vignettes referring to borrowing and passing on injecting equipment have been submitted to 505 injecting drug users in Glasgow. Injectors were asked to identify their own likely response in each of the situations described within the vignettes. It was shown that even among those injectors not reporting any actual sharing in the last 6 months a significant proportion would still be prepared to share injecting equipment within certain situations. The preparedness to share injecting equipment was seen to be influenced by such factors as social distance, sex and length of time injecting. It is suggested that even in situations where drug injectors may have modified their behaviour in the direction of lower levels of reported sharing, a propensity to share may remain. This suggests the continuing need to provide injectors with easy access to sterile injecting equipment; in addition, services working with injecting drug users may need to focus not only upon actual sharing behaviour but also upon what we have described here as the preparedness to share. Indeed, the latter dimension should stand as a warning to services of the potential for sharing injecting equipment to increase in the future.     

Hereditary Hemolytic Anemia Associated With Abnormal Membrane Lipids: Mechanism of Accumulation of Phosphatidyl Choline

In order to study the mechanism of theaccumulation of phosphatidyl choline(PC) in erythrocytes with abnormal erythrocyte phospholipids from patientswith a hereditary hemolytic anemia, thephospholipids of the erythrocytes werelabeled radioactively. Labeling of phosphatides was achieved by both passiveequilibration with preformed phosphatides, and active "acylase"-mediated incorporation of fatty acid (FA) in thepresence of glucose, ATP and coenzymeA. The labeled cells were then reincubated in fresh compatible sera and thecatabolism of the labeled erythrocytephospholipids was followed. In addition,total acylase capacity of erythrocytestroma was determined under optimalconditions in a system with excesslysophosphatide, FA, ATP, CoA, andMg⁺⁺. No differences in passive uptakeor release of phosphatides were found between the patients’ erythrocytes andcomparable reticulocyte-rich controls. Onthe other hand, overall active incorporation of FA into PC was abnormally increased in the patients’ erythrocytes,whereas incorporation of FA intophosphatidyl-ethanolamine (PE) was decreased. However, acylase capacity forboth lysophosphatidylcholine (LPC) andlysophosphatidylethanolamine (LPE) wasnormal in the patients’ cells. This apparent paradox could be explained by thesubsequent turnover of actively incorporated PC-FA which was found to bereduced. A brief labeling experiment designed to approximate pulse-chase conditions and to label primarily PC showed aconsiderable inhibition of the subsequenttransfer of PC-FA to PE upon reincubation in fresh serum. This transfer haspreviously been shown to be responsiblefor a significant portion of PC-FA catabolism. Reincubation in hyperlipemicsera obtained from patients with liverdisease or artificially enriched with PCdid not influence the abnormal outflow ofphosphatide-FA in actively labeled cells.The findings were consistent with theconcept that PC accumulated in thesecells because of a defect in the catabolismof actively incorporated PC-FA. This defect appeared to be in the transfer ofPC-FA to PE prior to final release fromthe cell. Passive exchange pathways andthe active anabolic acylase pathway werenot abnormal in these patients’ erythrocytes.

Submitted on March 4, 1971 Revised on May 4, 1971 Accepted on May 10, 1971