Pulmonary embolism--the role of thrombolytic therapy in its management

In massive pulmonary embolism where there may be evidence of right ventricular dysfunction and acute pulmonary hypertension, anticoagulation therapy alone may prove inadequate. In such situations use of thrombolytic agents produces an improvement in haemodynamics compared to anticoagulants alone, although studies to date have been too small to address the issue of mortality benefit. It would appear that all age groups gain benefit from the use of thrombolytics. Studies that have compared thrombolytic agents and anticoagulants are discussed. In addition, the issues of the choice of thrombolytic agent and the different modes of delivery of therapy are addressed.

Cardio-oesophageal reflex in humans as a mechanism for "linked angina'

The aim of this study was to investigate the hypothesis that oesophageal acid stimulation reduces coronary blood flow in humans as a result of the presence of a cardio-oesophageal reflex which may provide a mechanism for "linked angina'. We studied the effect of oesophageal acid stimulation on coronary blood flow in 35 syndrome X patients and 24 heart transplant patients. A fine tube was positioned into the patient's distal oesophagus. An intracoronary Doppler catheter was positioned in the proximal left anterior descending coronary artery for coronary blood flow measurements. Oesophageal instillation of 0.1 M hydrochloric acid was performed (60 ml over 5 min) and the measurements were repeated. The coronary blood flow was significantly reduced by acid oesophageal stimulation in the syndrome X group [pre-acid 78.9 +/- 36.4 ml. min-1, post-acid 50.8 +/- 32.9 ml.min-1 (P = 0.0001)]. However, coronary blood flow in the heart transplant group, in whom the heart is denervated, was unaffected by acid infusion. We conclude that oesophageal acid stimulation can produce angina and significantly reduce coronary blood flow in humans. The lack of any significant effect in the heart transplant group, in whom the heart is denervated, suggests a neural reflex.

Coronary flow reserve and oesophageal dysfunction in syndrome X

The relative prevalence of abnormalities of coronary flow reserve and oesophageal function was ascertained in 32 syndrome X patients with typical angina chest pain, a positive exercise test, and normal coronary arteries. Coronary flow reserve in response to a hyperaemic dose of papaverine was measured using an intracoronary Doppler catheter positioned in the left anterior descending coronary artery. An abnormal coronary flow reserve was defined as being < 3.0. Patients were investigated for oesophageal dysfunction by manometry and 24-hour pH monitoring. Thirteen patients had an impaired coronary flow reserve (group 1) and 19 patients had a normal flow reserve (group 2). Eight of the 13 group 1 patients (62%) and 13 of the 19 group 2 patients (68%, p = NS) had evidence of oesophageal dysfunction on either manometry or pH studies. Therefore, a total of 26 (81%) syndrome X patients had either an abnormality of coronary flow reserve or oesophageal dysfunction suggesting that chest pain in these patients may be due to myocardial ischaemia or oesophageal dysfunction, thus confirming the heterogeneous nature of this syndrome. The prevalence of oesophageal abnormalities was independent of any abnormalities of coronary flow reserve.

Phosphoinositide-dependent in vitro phosphorylation of profilin by protein kinase C. Phospholipid specificity and localization of the phosphorylation site

Phosphoinositides bind to profilin and regulate actin-based cytoskeletal protein assembly. We report here that profilin is phosphorylated in vitro by protein kinase C (PKC) in the presence of phosphoinositides and micromolar concentrations of calcium. PKC-mediated phosphorylation of profilin was observed only in the presence of phosphoinositides; phosphatidylserine and diacylglycerol (known activators of PKC) and other lipids, including phosphatidic acid and phosphatidylglycerol phosphate, did not activate the phosphorylation. The activation of PKC-mediated phosphorylation of profilin by phosphoinositides was as follows: phosphatidylinositol (PI) 4-phosphate (K(m) = 18 microM) > PI 4,5-bisphosphate (K(m) = 30 microM) > PI (no activation). About 0.5 mol phosphate was incorporated per mol of profilin. Phosphorylation of profilin by PKC was not affected by the presence of various concentrations of actin. Phospho-amino acid analysis showed serine to be the only amino acid phosphorylated. The amino acid sequence of a phosphopeptide from CNBr-digested profilin corresponded to the COOH-terminal peptide of profilin (Ala-Ser-His-Leu-Arg-Ser-Gln-Tyr). Further digestion of this phosphopeptide by trypsin generated two phosphopeptides (Arg-Ser-Gln-Tyr and Ser-Gln-Tyr), thereby confirming that the phosphorylation site was the antepenultimate Ser (Ala-Ser-His-Leu-Arg-Arg-Ser(P)-Gln-Tyr).

The Subcutaneous Heparin and Angioplasty Restenosis Prevention (SHARP) trial. Results of a multicenter randomized trial investigating the effects of high dose unfractionated heparin on angiographic restenosis and clinical outcome

OBJECTIVES

We sought to determine whether 12,500 IU of unfractionated heparin given subcutaneously twice daily for 4 months after percutaneous transluminal coronary angioplasty beneficially influences the subsequent rate of angiographic restenosis and the incidence of clinical events.

BACKGROUND

Heparin has been shown to exhibit powerful antiproliferative effects against smooth muscle cells in several animal models.

METHODS

A randomized trial with blinded data analysis was undertaken to assess the effect of unfractionated subcutaneous heparin on angiographic restenosis after coronary angioplasty. After successful angioplasty, patients were randomized to receive no heparin or 12,500 IU of heparin given subcutaneously twice daily for 4 months. Quantitative coronary angiography was performed before angioplasty, immediately after angioplasty and at follow-up ("early" [before 4 months] or electively [at 4 months]).

RESULTS

The study group comprised 339 patients, 167 randomly assigned to receive heparin, 172 to receive no heparin. Repeat cardiac catheterization was performed in 90% of randomized patients. At early and elective restudy (mean 4.2 months), the mean +/- SD difference in minimal lumen diameter between the postangioplasty and follow-up measurement was -0.55 +/- 0.58 mm for the no heparin group and -0.43 +/- 0.59 mm for the heparin group (p = NS). Clinical events during the follow-up period did not differ significantly between groups: fatal myocardial infarction (1 patient in each group), coronary bypass grafting (5 patients in each group), repeat angioplasty (12 in the no heparin, 6 in the heparin group), angina at 4-month assessment (33% in the no heparin, 32% in the heparin group).

CONCLUSIONS

Long-term treatment with high dose subcutaneous heparin (12,500 IU twice daily) for 4 months did not favorably influence angiographic or clinical outcome after coronary angioplasty.

Differential effects of spermine on phosphatidylinositol 3-kinase and phosphatidylinositol phosphate 5-kinase

The metabolism of phosphoinositides plays an important role in the signal transduction pathways. We report here that naturally occurring polyamines affect the activities of phosphatidylinositol (PI) 3-kinase and PI 4-phosphate (PIP) 5-kinase differently. While polyamines inhibited the PI 3-kinase activity, they stimulated the activity of PIP 5-kinase in the order of spermine > spermidine > putrescine. Spermine inhibited the PI 3-kinase activity in a concentration-dependent manner with an IC50 of 100 microM. On the other hand, spermine (5 mM) stimulated the activity of PIP 5-kinase 2-3 fold. Kinetic studies of spermine-mediated inhibition of PI 3-kinase revealed that it was noncompetitive with respect to ATP. The effect of Mg2+ and PIP2 concentration on kinase activity was sigmoidal, with spermine inhibiting PI 3-kinase activity at all PIP2 concentrations. While 1 mM calcium stimulated PI 3-kinase activity at submaximal concentrations of Mg2+ (1.25 mM), inhibition was observed at optimal concentration of Mg2+ (2 mM). We propose that spermine may modulate the cellular signal by virtue of its differential effects on phosphoinositide kinases.

Phosphatidylinositol 3-kinase: inhibition of intrinsic protein-serine kinase activity by phosphoinositides, and of lipid kinase activity by Mn2+

Phosphatidylinositol (PI) 3-kinase is composed of 110 kDa catalytic and 85 kDa regulatory subunits. The 110 kDa subunit has two intrinsic kinase activities, i.e., Mn(2+)-dependent protein-serine kinase and Mg(2+)-dependent lipid kinase activities. These intrinsic kinases have been reported to be interdependent: protein-serine kinase phosphorylates the 85 kDa subunit of PI 3-kinase, which upon phosphorylation inhibits the lipid kinase activity of PI 3-kinase. We report here that phosphoinositides can selectively inhibit the protein-serine kinase activity of PI 3-kinase without affecting lipid kinase activity. This inhibition depends on the phosphorylation status of the phosphoinositides, i.e., PI 4,5-bisphosphate > PI 4-phosphate >> PI. Mn2+ (2 mM) protected protein kinase activity from phosphoinositides-mediated inhibition if added prior to interaction of PI 3-kinase with phosphoinositides. On the other hand, Mn2+ (2 mM) inhibited lipid kinase activity independent of its effect on the protein kinase activity of PI 3-kinase. The present study suggests that the protein-serine kinase and the lipid kinase activities of PI 3-kinase can be selectively inhibited by phosphoinositides and Mn2+ respectively.

Syndrome X--angina and normal coronary angiography

It is clear that angina pectoris with normal coronary arteries is a heterogeneous and ill-defined syndrome that encompasses different pathogenic entities. Differences in patient selection and in definition of 'syndrome X' has made comparison between different study groups rather difficult. Two decades of investigations have not revealed a specific cause of this syndrome. There is now a general belief that syndrome X probably encompasses several pathophysiological disease entities and the mechanisms involved in syndrome X remain to be fully elucidated.

Insertion/deletion polymorphism in the angiotensin-converting enzyme gene and risk of restenosis after coronary angioplasty

Early restenosis in over 30% of cases limits the benefits of percutaneous transluminal coronary angioplasty (PTCA). The mechanisms that underlie restenosis are uncertain, although experimental evidence suggests that the renin-angiotensin system is involved in the vascular response to angioplasty. An insertion(I)/deletion(D) polymorphism in the angiotensin-converting enzyme (ACE) gene, which influences plasma ACE level, has been associated with an increased risk of myocardial infarction in those with the DD genotype. To investigate whether this polymorphism influences the risk of restenosis after PTCA, 233 patients who underwent single-vessel angioplasty in the Subcutaneous Heparin and Angioplasty Restenosis Prevention (SHARP) study were genotyped for the I/D polymorphism and pre-PTCA, post-PTCA, and 4-month clinical and quantitative angiographic data were compared in the three genotype groups. The groups, (II 53, ID 117, and DD 63) were well matched for baseline clinical and both pre- and post-PTCA angiographic features. At 4-month follow-up there was no significant difference between the genotype groups with respect to any of the quantitative angiographic criteria of restenosis: minimal luminal diameter at the site of the angioplasty (DD 1.35 [SE 0.10] mm, ID/II 1.43 [0.05] mm, difference -0.08 [95% CI -0.30 to 0.14]), numbers of subjects with more than 50% diameter stenosis (DD 49%, ID/II 46%, relative risk 1.06 [0.79 to 1.43]), or the number of subjects with more than 50% loss of the acute diameter gain after PTCA (DD 54%, ID/II 43%, 1.26 [0.94 to 1.67]). Likewise, there was no difference in the number of subjects with angina or a positive exercise stress test. We conclude that, in patients undergoing elective PTCA, the I/D polymorphism in the ACE gene does not influence the extent of restenosis, and typing for the polymorphism will not be a useful predictor of risk before the procedure.

The serum concentration of active transforming growth factor-beta is severely depressed in advanced atherosclerosis

Recent evidence has led us to propose that transforming growth factor-beta (TGF-beta) is a key inhibitor of atherosclerosis. We show here that a population of patients with advanced atherosclerosis all have less active TGF-beta in their sera than patients with normal coronary arteries, with a fivefold difference in average concentration between the two groups. This correlation with atherosclerosis is much stronger than for other known major risk factors and it may therefore have important diagnostic and prognostic significance. Aspirin medication correlates with an increase in active TGF-beta concentration, indicating that therapeutic interventions for TGF-beta are possible.

Measurements of human coronary vascular impedance

The aim of this study was to develop a method of measuring human coronary circulation impedance in a clinical setting. The authors measured coronary flow reserve (CFR) in 27 patients with chest pain and normal coronary arteries. A Judkins-style, 8F Doppler-tipped angiographic catheter was positioned in the left coronary ostium. Resting coronary flow velocity (RFV) and response to a hyperemic 12 mg intracoronary dose of papaverine (PFV) were measured. The signals were recorded by a recorder connected to a microprocessor with analogue-to-digital converter and a maths coprocessor. Using this the authors could obtain values for impedance at RFV (IR) and at PFV (IP). The CFR was defined as the ratio: PFV/RFV. An impedance index (II) was obtained as the ratio of coronary vascular impedance at peak hyperemia to the impedance at rest. The CFR was 3.2 +/- 1.2 and the II was 0.33 +/- 0.11. There was a strong inverse correlation between the CFR and the II (r = -0.9). The authors conclude that this new approach may allow a further insight into the coronary pathophysiology and may become useful in clinical cardiology, eg, in the assessment of heart transplant and Syndrome X patients.

Acute myocardial infarction in angiographically normal coronary arteries following induction of general anesthesia

Coronary spasm may occur with angiographically normal and diseased coronary arteries. General anesthesia has been described only rarely as a triggering event for coronary artery spasm, and only once before in the presence of angiographically normal coronary arteries. We have now seen three patients presenting with acute ST-segment elevation following induction of general anesthesia with enzyme evidence of myocardial necrosis in two patients. Cardiac catheterization was performed in all three patients with one of the procedures performed on an emergency basis owing to hemodynamic compromise. All three patients demonstrated angiographically normal coronary arteries. The electrocardiograms and coronary arteriograms are presented, and possible mechanisms for the injury pattern seen on the electrocardiogram are discussed. Coronary vasospasm causing an acute injury pattern on the electrocardiogram can be caused by general anesthesia and has to be recognized promptly and treated appropriately to prevent more serious complications.

Early complications after dual chamber versus single chamber pacemaker implantation

This study was performed to compare the frequency of early complications after single chamber versus dual chamber permanent pacemaker implantation. Early complication was defined as one occurring in the 6-week period following implantation. We prospectively analyzed consecutive pacemaker implantation from January 1987 to June 1993 at our regional center. All complications were also analyzed for the relationship to operator experience, the venous access route, and the presence of temporary pacing wire at the time of implantation of the permanent pacing system. A total of 2019 new pacemaker units were implanted during this period. 1733 patients (85.8%) received a VVI pacemaker and 286 (14.2%) a DDD unit. Wound infection occurred in 11 (0.6%) VVI patients and 6 (2.1%) DDD patients. Lead displacement occurred in 18 (1%) VVI patients and 15 (5.2%) DDD patients (11 [3.8%] atrial and 4 [1.4%] ventricular). There were 10 (0.6%) pneumothoraces, 9 (0.5%) hematomas requiring drainage, 1 (0.06%) chylocele, and 2 (0.1%) deaths in the VVI group. There were 2 (0.7%) pneumothoraces, 2 (0.7%) hematomas, and no deaths in the DDD group. There was no significant increase in complications for experienced infrequent implanters (< 12 systems per year). In both groups the subclavian approach was associated with a risk of pneumothorax when compared to the cephalic approach. The rate of wound infection was higher in patients who had a temporary pacing wire in place. The use of prophylactic antibiotics does not appear to affect the incidence of wound infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Atypical strain of hepatitis E virus (HEV) from north India

Hepatitis E virus (HEV) infection was detected during an epidemic in North India. Virus particles present in the stool of an acutely ill patient (YAM-67) was transmitted intravenously into rhesus monkeys (M. mulata) and orally to a human volunteer. Virus-like particles (VLPs) of 32-34 nm were detected in the bile of monkeys and in the stools of the human volunteer by means of solid phase immune electron microscopy (SPIEM) with acute homologous and heterologous sera. The VLPs were confirmed to be HEV by a reverse transcription polymerase chain reaction (RT-PCR). Virus-like particles from human volunteer stools were passaged further into rhesus monkeys. A bimodal rise in aminotransferase levels were observed in the animals, and liver histopathology indicated mild to severe form of hepatitis. Further, SPIEM and RT-PCR analysis in monkey bile revealed presence of virus from 15 to 45 days post-inoculation. Rechallenge of the animals 6 months after recovery with the same viral inoculum failed to produce abnormal liver function tests indicating the presence of protective immunity during this period. The VLPs in the stool from the patient (YAM-67) with epidemic hepatitis were found to retain infectivity even after several cycles of freeze-thawing and exposure at 37 degrees C for 2 days. Moreover, these VLPs from the patient, human volunteer, and monkeys did not react with an anti-HEV chimpanzee serum from NIH, Bethesda, MD. These findings indicate that this North India isolate of HEV is an atypical strain of HEV. The present study further validates that the rhesus monkey is a suitable experimental model for HEV.

Abnormal cardiac pain perception in syndrome X

OBJECTIVES

The purpose of this study was to determine whether a diminished cardiac pain threshold contributes to chest pain in patients with syndrome X.

BACKGROUND

There have been some reports of an altered pain perception in syndrome X.

METHODS

Intracardiac catheter manipulation was performed in four groups of patients (syndrome X [group 1, 36 patients]; mitral valve disease and normal coronary arteries [group 2, 36 patients]; mitral valve disease and coronary artery disease [group 3, 36 patients]; and heart transplant recipients with normal coronary arteries [group 4, 36 patients]). Coronary flow velocity was measured in patients with syndrome X and in transplant recipients by use of an intracoronary Doppler catheter positioned in the left anterior descending coronary artery at intracardiac catheter manipulation. Coronary flow reserve in response to papaverine was also measured in patients with syndrome X and in transplant recipients.

RESULTS

Intracardiac stimulation produced typical anginal chest pain in 34 group 1 (syndrome X) patients (94%). However, chest pain was produced only in five patients (14%) in group 2, seven patients (19%) in group 3 and no patients in group 4. There were no significant changes in coronary blood flow velocity associated with chest pain in group 1 patients. Coronary flow reserve in response to a hyperemic dose of intracoronary papaverine was significantly lower in the syndrome X group. There was no significant difference in the prevalence with which the stimulation tests produced chest pain in patients with syndrome X with an impaired coronary flow reserve or a positive radionuclide scan.

CONCLUSIONS

The results of our study suggest that abnormal cardiac pain perception is a fundamental abnormality in syndrome X.

Is coronary flow reserve in response to papaverine really normal in syndrome X?

BACKGROUND

An impaired coronary flow reserve in syndrome X has been demonstrated by many studies. Recently, however, a normal coronary flow reserve in response to papaverine was reported, but the number of patients in these studies was small. The aim of this study was to investigate whether coronary flow reserve in response to intracoronary papaverine is really impaired in syndrome X.

METHODS AND RESULTS

We investigated 53 syndrome X patients (typical angina, a positive exercise test, and completely normal coronary arteries on angiography) and 26 heart transplant patients with normal coronary arteries (control group). All antianginal medications were stopped 48 hours before the study. A 3.6F intracoronary Doppler catheter was positioned in the proximal left anterior descending coronary artery and was connected to a Millar velocimeter. The coronary blood flow velocity at rest and in response to a hyperemic dose of papaverine was measured. Coronary flow reserve was defined as the ratio of hyperemic coronary blood flow velocity in response to papaverine and resting coronary blood flow velocity. The coronary flow reserve (mean +/- SD) in the syndrome X group was 2.72 +/- 1.39. The coronary flow reserve in the control group was significantly higher at 5.22 +/- 1.26 (P < .01). In both groups there was no significant difference in the heart rate or the mean arterial pressure during the study.

CONCLUSIONS

Our study shows that coronary flow reserve in response to intracoronary papaverine is impaired in syndrome X patients.

Hepatitis E virus: epidemiological, clinical and serological studies of north Indian epidemic

BACKGROUND

A large waterborne epidemic of viral hepatitis occurred in the city of Karnal (Haryana) from February to April 1987. An attempt was made to study the epidemic clinically, serologically and etiologically.

METHODS

A house-to-house search of the city was conducted for the detection of acute hepatitis cases. Patients willing to give blood samples for liver function tests were studied.

RESULTS

A total of 1273 persons (0.79% of persons surveyed) were affected by viral hepatitis. Of the 477 clinically and biochemically documented cases, more than 75% were adults, while only 11% were less than 10 years old. Children below 15 years of age and females had a significantly higher incidence of anicteric hepatitis. Serological markers for acute hepatitis A and B viruses were absent in 85% of patients. Antibodies to hepatitis E virus (HEV) were detected in 84% of acute phase sera studied by indirect immunofluorescence assay. Liver biopsy showed characteristic features of cholangitic hepatitis. Three of 19 pregnant females who developed hepatitis died. No residual clinical or biochemical abnormality was detected in any of the patients followed up for 8 months. This epidemic correlated with the timing of unsupervised digging of lanes to provide new tap water connections to houses in the congested area of the city. This resulted in damage to the sewerage system and leakages which contaminated drinking water supply.

CONCLUSION

HEV was transmitted by contaminated drinking water in this epidemic. Most affected individuals were adults, and recovered without sequelae. Affected pregnant women had a worse outcome.

Interaction of protein kinase C and phosphoinositides: regulation by polyamines

Phosphatidylinositol 4,5-bisphosphate (PIP2) activates protein kinase C (PKC) in the presence of phosphatidylserine and calcium. Recently it has been demonstrated that direct interaction of PKC with PIP2 in the absence of divalent cation inactivates this kinase. In the present study, the interaction of natural aliphatic polyamines with phosphoinositides was investigated for its possible relevance to PKC-mediated protein phosphorylation. PKC/phosphoinositide interaction was studied by monitoring the changes in (a) intrinsic fluorescence of the enzyme, and (b) PKC activity (protamine sulphate or histone III-S as substrate). All the phosphoinositides: PIP2, phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol (PI) inactivated PKC with an IC50 of 0.4 microM for PIP2, 5 microM for PIP and 10 microM for PI. Hydrogenated PIP2 behaved similarly to that of natural PIP2. Time-dependent studies showed very rapid inactivation of PKC by PIP2. The polyamines spermine and spermidine at physiological concentrations protected PKC from phosphoinositides-mediated inactivation when added prior to PKC interaction with phosphoinositides. Putrescine was least effective. Addition of spermine or spermidine to PKC/phosphoinositides incubation mixture did not reverse PKC activity indicating that the inactivation of PKC by phosphoinositides is irreversible. Fluorescence quenching experiments showed that phosphoinositides inactivate PKC by inducing conformational changes of the enzyme that are prevented by spermine. We propose that polyamines protect PKC and possibly other protein kinase from phosphoinositides-mediated inactivation, and that inactivation of protein kinases by phosphoinositides may not have physiological relevance.

Effect of transcutaneous electrical nerve stimulation on coronary blood flow

BACKGROUND

Although neurostimulation has been shown to be of benefit in angina pectoris, the exact mechanism of its action is not clear. This study was performed to examine the effect of transcutaneous electrical nerve stimulation on coronary blood flow.

METHODS AND RESULTS

The effect of transcutaneous electrical nerve stimulation was studied in 34 syndrome X patients (group 1), 15 coronary artery disease patients (group 2), and 16 heart transplant patients (group 3). Coronary blood flow velocity (CBFV) in the left coronary system was measured at rest and after a 5-minute stimulation period with a Judkins Doppler. There was a significant increase in the resting CBFV in group 1 (from 6.8 +/- 4.1 to 10.5 +/- 5.7 cm/s, P < .001) and group 2 (from 6.8 +/- 4.1 to 10.5 +/- 5.7 cm/s, P < .001). However, there was no significant change in the resting CBFV in group 3. There were no significant changes in the coronary arterial diameters as a result of neurostimulation. There was a significant decrease in the epinephrine levels in group 1 (from 79.6 +/- 17.8 to 58.5 +/- 17.5 ng/L, P = .01) and group 2 (from 102.2 +/- 27.2 to 64.1 +/- 19.1 ng/L, P = .01).

CONCLUSIONS

Transcutaneous electrical nerve stimulation can increase resting coronary blood flow velocity. The findings suggest that the site of action is at the microcirculatory level and that the effects may be mediated by neural mechanisms.

Hyperinsulinemia, coronary artery disease and syndrome X

OBJECTIVES

This study was conducted to compare the insulin responses to an oral glucose load in healthy volunteers and patients with syndrome X and patients with coronary artery disease.

BACKGROUND

An abnormal coronary flow reserve has been reported in syndrome X by several investigators. However, its cause is not known. Recently, it has been suggested that elevated insulin levels in syndrome X may contribute to microvascular dysfunction.

METHODS

Insulin responses to an oral glucose load (75 g) were compared in 17 patients with coronary artery disease, 17 patients with chest pain, positive exercise test findings, normal coronary arteries and impaired coronary flow reserve (syndrome X) and 17 healthy volunteers (control subjects). All were matched for age, gender and body weight. Patients with overt diabetes mellitus or hypertension were excluded. Venous blood samples were taken during fasting and at 30, 60, 90 and 120 min after the glucose load. Samples were analyzed for glucose, immunoreactive insulin and C peptides.

RESULTS

There was no significant difference in the glucose levels at all sampling points among the three groups. The C peptide and immunoreactive insulin levels were significantly higher than values in the control group at 60, 90 and 120 min in the groups with syndrome X and coronary artery disease. The peak responses and the areas under the curve were also significantly greater in the latter two groups. There was no significant difference at all sampling points between the group with syndrome X and the group with coronary artery disease.

CONCLUSION

Patients with syndrome X have stimulated hyperinsulinemia, which may contribute to the pathophysiology of syndrome X.

Coronary flow reserve measurements with a new Judkins-style Doppler angiographic catheter

The authors assessed whether measurements obtained by Judkins-style Doppler catheters are comparable to those achieved with the intracoronary Doppler technique in 42 patients with normal coronary arteries on angiography (19 syndrome X and 23 heart transplant patients). Resting coronary flow velocity and response to a hyperemic intracoronary dose of papaverine was measured with a Judkins-style, 8F Doppler-tipped catheter positioned in the left coronary ostium and a 3.6F intracoronary Doppler catheter positioned in the proximal left anterior descending artery. Mean coronary flow velocity at rest was significantly higher with the Judkins Doppler (10.1 +/- 4.6 vs 6.3 +/- 4.5 cm/sec, p < 0.01). The mean coronary flow velocity at peak hyperemia was also significantly higher with the Judkins Doppler (33.7 +/- 14.1 vs 19.7 +/- 11.5 cm/sec, p < 0.01). Coronary flow reserve was 3.57 +/- 1.3 with the Judkins Doppler and 3.47 +/- 1.2 with the intracoronary Doppler (r = 0.85). A second study was performed in 14 heart transplant patients with the intracoronary Doppler positioned in the left main coronary artery. The resting and hyperemic flow velocities were again higher with the Judkins Doppler but the differences were not statistically significant. There was again a strong correlation between the Doppler catheters for coronary flow reserve measurements. The Judkins-style Doppler technique appears to be a quick, safe, and accurate alternative to the intracoronary Doppler technique.

Amyloid beta-protein stimulates casein kinase I and casein kinase II activities

Amyloid beta-protein (A beta) is the major protein of cerebrovascular and plaque amyloid in Alzheimer's disease (AD). Extensive evidence has demonstrated abnormal protein phosphorylation in this disease. We investigated the effect of synthetic A beta with the amino-acid sequence corresponding to cerebrovascular A beta and plaque A beta on the activities of casein kinase I (CK I) and casein kinase II (CK II). These enzymes were purified from bovine brain and casein was used as a substrate. A beta was found to stimulate markedly CK I- and CK II-mediated phosphorylation of casein in a concentration-dependent manner. The effect of plaque A beta was considerably higher than that of cerebrovascular A beta. Heparin, which is known to be a specific inhibitor of CK II, completely inhibited A beta-stimulated CK II activity. A beta itself was not a substrate for casein kinases. These findings were confirmed using other substrates for CK I and CK II. The experiments with synthetic CK II-substrate peptide (Leu-Glu-Leu-Ser-Asp-Asp-Asp-Asp-Glu) and the phosphorylation of erythrocyte membrane proteins by intrinsic membrane-bound CK I in erythrocytes showed marked stimulation in activities of casein kinases in the presence of A beta 1-40 or blocked A beta. We propose that A beta, by stimulating casein kinases, may contribute to abnormal protein phosphorylation in AD, in particular to increased phosphorylation of microtubule-associated proteins, leading to the neurofibrillary tangles formation and neurodegeneration in this disease. Interaction of A beta with protein kinases, thus, may characterize the beginning of the disease.

A new medium for rapid slide culture of tubercle bacilli

Human blood medium (HBM) and egg enriched sheep blood medium (SBM) were evaluated to see their efficacy for primary culture of tubercle bacilli. SBM is found to be equally effective compared to HBM. Both types of media were associated with a low rate of contamination (2.75%). Availability of culture results after 7 days compared to 6 weeks on Lowenstein-Jensen media is a distinct advantage of slide culture method with a possible use in primary isolation and in evaluation of drug sensitivity pattern of Mycobacterium tuberculosis.

Clinical presentation and functional prognosis in syndrome X

OBJECTIVES

To assess the effect of clinical presentation on functional prognosis in patients with syndrome X.

DESIGN

A prospective study. Patients with syndrome X presenting with unstable angina and stable angina were followed up with a questionnaire to examine their functional state.

PATIENTS

41 patients with syndrome X and unstable angina and 41 patients with syndrome X and stable angina. Syndrome X was defined as typical anginal chest pain, a positive exercise test, and normal coronary angiogram.

SETTING

Regional cardiothoracic centre.

RESULTS

The mean follow up time was 36 (range 20-51) months for the unstable angina group and 35 (range 19-51) months for the stable angina group. No patient was lost to follow up in either group. At follow up 28 patients in the unstable angina group were pain free compared with 15 patients in the stable angina group (p = 0.008). Seven patients in the unstable angina group had further hospital admission with chest pain after the cardiac catheterisation compared wtih 12 patients in the stable angina group (NS). Seven patients in the unstable angina group believed that they had heart disease compared with 27 in the stable angina group (p < 0.001). 26 patients in the unstable angina group but only eight patients in the stable angina group were unlimited in their physical activity (p < 0.001). 12 patients in the unstable angina group compared with 27 patients in the stable angina group were unable to work normally because of chest pain (p < 0.001). The mean (SD) duration of symptoms before cardiac catheterisation was 7.9 (4.7) months in the unstable angina group and 13.4 (5.6) months in the stable angina group (p < 0.001). 10 patients in the unstable angina group and 24 patients in the stable angina group still attended hospital outpatient clinics because of chest pain (p = 0.004). 16 patients in the unstable angina group and 29 patients in the stable angina group were still taking regular antianginal medication (p < 0.001).

CONCLUSIONS

Patients with syndrome X who present with unstable angina have a significantly better functional prognosis than those presenting with symptoms of stable angina. This may reflect differences in underlying pathophysiological mechanisms.

Activation of protein kinase C by phosphatidylinositol 3,4,5-trisphosphate

Phosphatidylinositol 3-kinase (PI 3-kinase) was partially purified from rat liver cytosol and used to synthesize phosphatidylinositol 3,4,5-trisphosphate (PIP3), using phosphatidylinositol 4,5-bisphosphate (PIP2) as a substrate. Purified PIP3 (free of chromatographic oxalate) activated protein kinase C (PKC) in the presence of phosphatidylserine and calcium (PKC -cofactors) in a concentration-dependent manner. In the absence of these cofactors, effect of PIP3 was not observed. Comparison of the effects of PIP3 and PIP2 on PKC activity indicates that PIP3 is a more potent PKC-activator than PIP2. The affinity of PKC to PIP3 was 4 fold higher than that to PIP2 (KPIP3 = 0.022 and KPIP2 = 0.087 mol %), while its maximal velocity (Vmax) was similar to that of PIP2-stimulated PKC activity (0.4 - 0.5 mumol/mg/min). These results suggest a physiological role for PIP3 in signal transduction, and support the previous finding (Chauhan et al. (1991) Arch. Biochem. Biophys. 287,283) that PKC-activation by phosphoinositides increases with the state of phosphorylation of these lipids. We propose that PIP3 by activating PKC may initiate a cascade of events from PIP3-->PKC- activation-->effects on other protein kinases such as MAP-kinase-->gene expression.

Magnesium protects phosphatidylinositol-4,5-bisphosphate-mediated inactivation of casein kinase I in erythrocyte membrane

Recent reports suggest that membrane-bound casein kinase I (MBCK I) activity in erythrocytes is inactivated by exogenously added phosphatidylinositol 4,5-bisphosphate (PIP2) (Bazenet et al. (1990) J. Biol. Chem. 265, 7369-7376; Brockman and Anderson (1991) J. Biol. Chem. 266, 2508-2512). Here we report that PIP2-mediated inhibition of MBCK I in erythrocytes is only observed if exogenous PIP2 and the kinase are allowed to interact in the absence of Mg2+. Prior incubation of PIP2 with 1 mM Mg2+ prevents the inactivation of MBCK I by PIP2. Other divalent cations (Ni2+, Co2+, Mn2+, Cd2+, Ca2+) and trivalent metal ions (La3+, Cr3+, Al3+) did not protect MBCK I from PIP2-mediated inactivation, indicating that the protective effect is specific for Mg2+ only. We propose a role of Mg2+ in the interaction of CK I with phosphoinositides, and that PIP2-mediated inhibition of protein kinase(s) may be a non-physiological phenomenon.

Effect of hyperventilation and mental stress on coronary blood flow in syndrome X

OBJECTIVES

To assess the effect of hyperventilation and mental stress on coronary blood flow and symptom production in patients with syndrome X.

DESIGN

A prospective study. Hyperventilation and mental stress tests were performed on the ward and were repeated in the cardiac catheter laboratory where coronary blood flow velocity was also measured with an intracoronary Doppler catheter in the left anterior descending coronary artery. Oesophageal manometry studies were also performed.

PATIENTS

29 patients with syndrome X (typical anginal chest pain, a positive exercise test, and normal coronary angiogram).

SETTING

A regional cardiothoracic centre.

RESULTS

Hyperventilation produced typical chest pain in 16 patients on the ward. 13 patients experienced their typical chest pain with mental stress test 5. Ten patients experienced chest pain with both hyperventilation and mental stress tests. This pattern was reproduced exactly when the tests were repeated in the cardiac catheter laboratory. Hyperventilation produced a significant increase in the rate-pressure product during ward and laboratory testing. There was, however, no significant change in the rate-pressure product on mental stress tests. The mean (SEM) coronary flow velocity decreased significantly on hyperventilation in the catheter laboratory from 10.0 (0.92) cm/s to 5.9 (0.72) cm/s (p < 0.001). There was also a significant reduction in the mean (SEM) coronary blood flow velocity on mental stress tests from 9.8 (0.86) cm/s to 7.4 (0.6) cm/s (p < 0.001). This reduction in flow velocity occurred in the absence of any changes in diameter of the left anterior descending artery. Further analysis showed that the coronary flow velocity was reduced significantly in only that group of patients in which hyperventilation and mental stress provoked chest pain. There was a significant increase in the arterial concentrations of noradrenaline on both hyperventilation and mental stress testing. Oesophageal manometry showed abnormalities in 17% of patients.

CONCLUSIONS

Both hyperventilation and mental stress can produce chest pain in patients with syndrome X and this is associated with a reduction in coronary blood flow velocity. The results of this study suggests that this reduction in coronary flow occurs as a result of increased microvascular resistance.

"Syndrome X" and coronary artery disease

BACKGROUND

"Syndrome X" is a heterogeneous disorder that probably encompasses several disease states. The long-term prognosis in syndrome X is good, although a significant number of patients continue to experience chest pain and remain functionally limited. Several studies have reported that the development of coronary artery disease in patients with syndrome X is rare. Our experience, however, has shown that patients diagnosed as having syndrome X may develop atherosclerotic coronary artery disease over a relatively short period of time.

METHODS

Three patients with syndrome X were studied with repeat coronary angiography.

RESULTS AND CONCLUSIONS

We describe the development of coronary artery disease in three syndrome X patients over a relatively short time after their normal coronary angiogram. Accordingly, the physician should remain alert to this possibility.

Effect of oesophageal acid instillation on coronary blood flow

To assess whether gastrointestinal factors can cause chest pain ("linked angina"), we studied the effect of oesophageal stimulation with acid on coronary blood flow in 20 syndrome X patients. Coronary blood flow velocity (CBFV) was measured with an intracoronary doppler catheter positioned in the proximal left anterior descending coronary artery. Acid stimulation produced typical anginal pain in 11 patients. Mean CBFV was significantly reduced from 7.3 (SD 4.0) to 4.4 (2.8) cm/s. Gastro-oesophageal reflux leading to reduced coronary blood flow may be a mechanism to explain linked angina.

Hepatitis E virus transmission to a volunteer

Hepatitis E virus (HEV) causes an enteric non-A, non-B hepatitis. The disease occurs in epidemic settings and sporadically, and viral transmission is thought to be faecal-oral. We present here a single volunteer study of HEV transmission followed by disease. Clinical and biochemical features of the infection correlated with HEV detection in the stools and sera by reverse transcription/polymerase chain amplification. IgG antibody has persisted for 2 years. The presence of HEV in serum before clinical signs appeared suggests that in endemic areas sporadic transmission of HEV may also occur parenterally.

Probucol reduces plasma and aortic wall oxysterol levels in cholesterol fed rabbits independently of its plasma cholesterol lowering effect

To understand further the antiatherogenic mechanism of probucol, the antioxidant effect of this agent was studied on specific cholesterol oxidation products in plasma and aortic wall in equally hypercholesterolemic New Zealand white rabbits. In order to maintain equal plasma total cholesterol levels, five control rabbits (C group) received a 1% followed by a 0.5% cholesterol enriched diet, while the probucol treated rabbits (C+P group) received a graded increase in the cholesterol supplemented diet from 1% to 3%; probucol supplementation was constant at 1%. After 9 weeks of feeding, the plasma oxysterols, cholest-5-ene-3 beta,7 alpha-diol, cholest-5-ene-3 beta,7 beta-diol, 5,6 beta-epoxy-5 alpha-cholestan-3 beta-ol, 5,6 alpha-epoxy-5 alpha-cholestan-3 alpha-ol and 5 alpha-cholestane-3 beta,5,6 beta-triol significantly increased over baseline levels in both experimental groups. However, the increase in all these products in plasma was 20-60% less in the C+P group than the C group (P < 0.05). Furthermore, the C+P aortic wall cholesterol oxide concentrations were 50-90% less than the C group (P < 0.05). The oxysterol pattern of the aortic wall was similar to plasma. Additionally, the aortic wall cholesterol content in the C+P group was 50% less than the C group (P < 0.05). The plasma cholesterol levels were not significantly different at any time point during the study and the cholesterol oxide content in the diets was the same. These results are consistent with the contention that the antioxidant properties of probucol serve as the basis for its antiatherogenic effects in vivo.

Kallmann's syndrome and dilated cardiomyopathy

A 52-year-old male previously known to have Kallmann's syndrome was admitted with congestive cardiac failure. He was found to have a dilated cardiomyopathy and died despite medical therapy. This report is the first known case of Kallmann's syndrome and dilated cardiomyopathy.

Impairment of coronary flow reserve in orthotopic cardiac transplant recipients with minor coronary occlusive disease

OBJECTIVE

Coronary occlusive disease is the major long-term complication after cardiac transplantation. The relation between minor angiographic abnormalities and myocardial perfusion has not been previously assessed in a large number of cardiac transplant patients.

DESIGN

Prospective study. Coronary flow reserve was measured with an intracoronary Doppler flow probe in the proximal left anterior descending coronary artery in each patient. A dose of intracoronary papaverine producing maximal vasodilation was then administered.

SETTING

A regional cardiothoracic centre and a supraregional transplant unit.

PATIENTS

Seven patients with chest pain but normal coronary anatomy (controls), and 61 cardiac transplant patients between three months and 10 years after operation (median 4.5 years). Twenty one cardiac transplant patients had angiographic evidence of minor coronary occlusive disease (mean (SD) percentage stenosis diameter 23% (6%)) in a primary or secondary coronary vessel (group 1), with 12 of these in the left anterior descending coronary artery (stenosis diameter (mean (SD) 24% (8%)). The remaining 40 transplant patients had normal coronary angiograms (group 2).

MAIN OUTCOME MEASURE

Coronary flow reserve was defined as the ratio of the peak flow velocity after papaverine to the resting flow velocity.

RESULTS

Group 1 patients had a noticeably impaired coronary flow reserve (2.6 (1.1)) compared with control patients (3.9 (0.4), p = 0.05) and, after adjusting for year after operation, compared with group 2 patients (3.8 (1.0), p < 0.001). No other variables were associated with a reduction in coronary flow reserve. Mean resting flow velocity was similar in all three groups (controls, 7.4 (4.6) cm/s; group 1, 7.5 (5.9) cm/s; and group 2, 7.3 (3.9) cm/s). Mean peak flow velocity response to papaverine was reduced in group 1 patients (18.1 (13.5) cm/s) relative to group 2 patients (27.5 (15.4) cm/s, p = 0.05) but not controls (28.4 (15.1) cm/s, p = 0.1).

CONCLUSIONS

Coronary flow reserve and the peak flow response to the coronary vascular smooth muscle relaxant papaverine are impaired in cardiac transplant patients with minor coronary occlusive disease. This disturbance of cardiac microvascular function may contribute to the late morbidity and mortality seen in cardiac transplant patients with coronary occlusive disease.

Coronary artery bypass grafting nine years after cardiac transplantation

Angina and increasing exertional dyspnea developed in a 53-year-old man 9 years after cardiac transplantation. Left heart catheterization revealed severe proximal triple coronary artery disease, and he underwent surgical revascularization. Now 18 months after the operation he continues to be free of symptoms.

Common aetiological agent for epidemic and sporadic non-A, non-B hepatitis

Enterovirus-like particles have been reported in the acute phase of both epidemic and sporadic non-A, non-B (NANB) hepatitis. To examine whether these particles were the causative agent in the two types of disease, 29 patients with acute viral hepatitis in a north Indian epidemic outbreak and 9 with sporadic acute disease were investigated. 25 (86%) of 29 patients with epidemic hepatitis and 5 (56%) of 9 with sporadic disease were diagnosed as having enterically-transmitted-NANB hepatitis by exclusion. Virus-like particles (VLP) of 30-34 nm were detected in stool of 1 patient with epidemic and 1 with sporadic hepatitis. The VLPs crossreacted serologically and a specific IgM response was seen in acute epidemic and sporadic serum samples. After inoculation with infected stool rhesus monkeys had a mild rise in liver enzymes, and bile samples contained VLPs. These results suggest that the aetiological agent in epidemic and sporadic disease is the same.