Sex and age differences of major cardiovascular events in patients after percutaneous coronary intervention

BACKGROUND

Women usually have higher risk after receiving percutaneous coronary interventions (PCIs) than men with coronary artery disease (CAD). The aim of this study was to investigate the association of sex differences with future outcomes in CAD patients undergoing PCI, to assess the role of age, and to extend observed endpoints to stroke and congestive heart failure.

METHODS

Six thousand six hundred forty-seven patients with CAD who received successful PCIs. The associations between clinic outcomes and sex were analyzed. The primary outcome was major cardiovascular events (MACE), including cardiac death, nonfatal myocardial infraction, and nonfatal stroke. The secondary outcome was MACE and hospitalization for heart failure (total CV events).

RESULTS

During a mean of 52.7 months of follow-up, 4833 men and 1614 women received PCI. Univariate and multivariate analyses showed that women were independently associated with an increased risk of cardiac death (HR, 1.78; 95% CI, 1.32-2.41), hospitalization for heart failure (HR, 1.53; 95% CI, 1.23-1.89), MACE (HR, 1.34; 95% CI, 1.10-1.63), and total CV events (HR, 1.39; 95% CI, 1.20-1.62). In the subgroup analysis, women aged under 60 years had higher cardiovascular risks than men of the same age category.

CONCLUSION

Women with CAD after successful PCI had poorer cardiovascular outcomes than men. Additionally, younger women (aged <60 years) were especially associated with a higher risk of developing future adverse cardiovascular outcomes.

Association between visit-to-visit blood pressure variability and adverse events in coronary artery disease patients after coronary intervention

Blood pressure variability (BPV) is independently associated with higher cardiovascular risks. However, whether BPV is associated with poor outcomes for coronary artery disease (CAD) patients after percutaneous coronary intervention (PCI) remained undetermined. We aimed to investigate the relationship between BPV and the outcomes of CAD patients undergoing PCI. Two thousand seven hundred and sixty-two CAD patients (1938 males, mean age 69.6 ± 12.9) who received PCI at Taipei Veterans General Hospital from 2006 to 2015 with multiple blood pressure measurements before and after the index PCI were enrolled. We calculated the standard deviation of systolic blood pressure, diastolic blood pressure, and pulse pressure as parameters of BPV. The primary endpoint was the composite of major adverse cardiovascular events [MACE comprising of cardiovascular death, nonfatal myocardial infarction (MI), and non-fatal stroke] and heart failure hospitalization (HHF). The key secondary endpoint was MACE. Both pre-PCI and post-PCI BPV were associated with CV events even after adjusting for co-morbidities and mean blood pressure. In Cox analysis, for every 1 mmHg increase in systolic BPV, the hazard ratio for the MACE + HHF, MACE, HHF, and cardiovascular death was 1.04 (95%CI: 1.03-1.05), 1.04 (95%CI: 1.02-1.05), 1.05 (95%CI: 1.04-1.06), and 1.06 (95%CI: 1.03-1.09), respectively. The association between BPV and cardiovascular risk is independent of blood pressure control status. The prognostic value of BPV was superior to mean blood pressure in both pre-PCI and post-PCI period. BPV is independently associated with cardiovascular events after PCI and has a better prognostic value than mean blood pressure suggesting the importance of maintaining stable blood pressure for CAD patients.

Optimal blood pressure for patients with end-stage renal disease following coronary interventions

Hypertension is a frequent manifestation of chronic kidney disease but the ideal blood pressure (BP) target in patients with coronary artery disease (CAD) with end-stage renal disease (ESRD) (eGFR < 15 ml/min/1.73m² ) still unclear. The authors aimed to investigate the ideal achieved BP in ESRD patients with CAD after coronary intervention. Five hundred and seventy-five ESRD patients who had undergone percutaneous coronary interventions (PCIs) were enrolled and their clinical outcomes were analyzed according to the category of systolic BP (SBP) and diastolic BP (DBP) achieved. The clinical outcomes included major cardiovascular events (MACE) and MACE plus hospitalization for congestive heart failure (total cardiovascular (CV) event).The mean systolic BP was 135.0 ± 24.7 mm Hg and the mean diastolic BP was 70.7 ± 13.1 mm Hg. Systolic BP 140-149 mm Hg and diastolic BP 80-89 mm Hg had the lowest MACE (11.0%; 13.2%) and total CV event (23.3%; 21.1%). Patients with systolic BP < 120 mm Hg had a higher risk of MACE (HR: 2.01; 95% CI: 1.17-3.46, p = .008) than those with systolic BP 140-149 mm Hg. Patients with systolic BP ≥ 160 mm Hg (HR: 1.84; 95% CI, 3.27-1.04, p = .04) and diastolic blood BP ≥ 90 mm Hg (HR: 2.19; 95% CI: 1.15-4.16, p = .02) had a higher risk of total CV event rate when compared to those with systolic BP 140-149 mm Hg and diastolic BP 80-89 mm Hg. A J-shaped association between systolic (140-149 mm Hg) and diastolic (80-89 mm Hg) BP and decreased cardiovascular events for CAD was found in patients with ESRD after undergoing PCI in non-Western population.

Systemic immune-inflammation index (SII) predicted clinical outcome in patients with coronary artery disease

BACKGROUND

This study examines the predictive value of a novel systemic immune-inflammation index (SII, platelet × neutrophil/lymphocyte ratio) in coronary artery disease (CAD) patients.

METHODS

A total of 5602 CAD patients who had undergone a percutaneous coronary intervention (PCI) were enrolled. They were divided into two groups by baseline SII score (high SII vs low SII) to analyse the relationship between SII groups and the long-term outcome. The primary outcomes were major cardiovascular events (MACE) which includes nonfatal myocardial infarction (MI), nonfatal stroke and cardiac death. Secondary outcomes included a composite of MACE and hospitalization for congestive heart failure.

RESULTS

An optimal SII cut-off point of 694.3 × 10⁹ was identified for MACE in the CAD training cohort (n = 373) and then verified in the second larger CAD cohort (n = 5602). Univariate and multivariate analyses showed that a higher SII score (≥694.3) was independently associated with increased risk of developing cardiac death (HR: 2.02; 95% CI: 1.43-2.86), nonfatal MI (HR: 1.42; 95% CI: 1.09-1.85), nonfatal stroke (HR: 1.96; 95% CI: 1.28-2.99), MACE (HR: 1.65; 95% CI: 1.36-2.01) and total major events (HR: 1.53; 95% CI: 1.32-1.77). In addition, the SII significantly improved risk stratification of MI, cardiac death, heart failure, MACE and total major events than conventional risk factors in CAD patients by the significant increase in the C-index (P < .001) and reclassification risk categories by significant NRI (P < .05) and IDI (P < .05).

CONCLUSIONS

SII had a better prediction of major cardiovascular events than traditional risk factors in CAD patients after coronary intervention.

Association of variability in uric acid and future clinical outcomes of patient with coronary artery disease undergoing percutaneous coronary intervention

BACKGROUND AND AIMS

Hyperuricemia is independently associated with cardiovascular disease (CVD) and is considered to be one of the major risk factors for CVD. However, the impact of inter-visit uric acid (UA) variability on cardiovascular risk remains undetermined.

METHODS

We enrolled 3202 patients with coronary artery disease (CAD), who received successful coronary intervention, in a cohort from Taipei Veterans General Hospital from 2006 to 2015. All post-baseline visits UA measurements using standard deviation (SD) were analyzed to correlate with long-term outcome. The primary outcome was the composite of cardiac death, nonfatal MI, nonfatal stroke (MACE). The secondary event was MACE and hospitalization for heart failure.

RESULTS

During an average 65.06 ± 32.1-month follow-up, there were 66 cardiovascular deaths, 175 nonfatal myocardial infarctions, 64 nonfatal strokes, 287 hospitalizations for heart failure, and 683 revascularization procedures. There was a linear association between high UA SD and future adverse events. Compared to the lowest quartile SD, subjects in the highest quartile SD had a higher risk of MACE (HR: 2.53, 95% CI: 1.78-3.59), myocardial infarction (HR: 2.43, 95% CI: 1.53-3.86), cardiovascular death (HR: 6.45, 95% CI: 2.52-16.55), heart failure-related hospitalization (HR: 3.43, 95% CI: 2.32-5.05), and total major CV events (HR: 2.72, 95% CI: 2.09-3.56). Furthermore, compared to the average achieved on-treatment UA value, increasing UA SD had a stronger association of higher risk of developing MACE (HR: 1.51, 95% CI: 1.36-1.68), myocardial infarction (HR: 1.37, 95% CI: 1.38-1.68), ischemic stroke (HR: 1.43, 95% CI: 1.13-1.82), CV death (HR: 1.77, 95% CI: 1.50-2.11), HF (HR: 1.43, 95% CI: 1.29-1.58), and total major CV events (HR: 1.46, 95% CI: 1.34-1.58).

CONCLUSIONS

High UA variability is associated with a higher risk of developing future cardiovascular events, suggesting the importance of maintaining stable serum UA levels and avoiding large fluctuations in CAD patients after percutaneous coronary intervention (PCI).

Chinese version of the Rotator Cuff Quality of Life questionnaire: Cross-cultural adaptation and validation in rotator cuff-impaired patients in Hong Kong

Purpose:

To adapt the Rotator Cuff Quality of Life (RC-QOL) questionnaire into traditional Chinese (Chi-RC-QOL) and to evaluate the validity and reliability in patients suffering from rotator cuff pathologies in Hong Kong.

Methods:

The Chi-RC-QOL will be constructed using the forward-translation followed by the backward-translation method. Thirty consecutive patients with clinically and radiologically confirmed rotator cuff pathology were recruited. Descriptive statistics will be followed by validity assessment using comparison with the Constant Shoulder (CS) score, University of California Los Angeles (UCLA) Shoulder Rating Scale, and Western Ontario Rotator Cuff (WORC) score. Parametric data will be tested using Pearson’s correlation coefficient for the total scores. Reliability was assessed using a test–retest interval of 30 min. The Cronbach’s α and intraclass correlation coefficient were calculated.

Results:

Cronbach’s α and internal consistency scores were high for all parts of the Chi-RC-QOL, with Cronbach’s α ranging between 0.89 and 0.98. Internal consistency scores range from 0.82 to 0.92, which can be regarded as an excellent correlation. Test–retest reliability was excellent for all parts of the Chi-RC-QOL with good absolute reliability. Chi-RC-QOL correlates well with the CS score, UCLA Shoulder Rating Scale, and the WORC score, with all being statistically significant.

Conclusions:

The current study adapted the RC-QOL to traditional Chinese version. The analysis confirmed the validity and reliability of the Chi-RC-QOL questionnaire.

Level of Evidence:

III.

A Case of Acute Calcific Tendinitis of the Hand: An Uncommon Condition that is Easily Overlooked and Misdiagnosed

Acute calcific tendinitis of the hand is uncommon, yet it has a high rate of misdiagnosis as it resembles other conditions such as fractures, inflammatory and infectious causes that give rise to pain and swelling in the hand. We present a case of acute calcific tendinitis in a middle age woman affecting the extensor pollicis longus to raise awareness of this uncommon, but easily treatable cause of pain and swelling. This case was first diagnosed as septic arthritis of the interphalangeal joint of the thumb. Correct diagnosis was made after careful review of history, physical examination findings, laboratory results and radiographs. (Hong Kong j. emerg.med. 2015;22:316-319)

Can Emergency Medicine Ward Shorten Hospital Length of Stay in Patients with Nasogastric Tube Related Coffee Ground Aspirate?

Introduction

The aim of this study was to determine whether elderly patients on nasogastric (NG) tube feeding who presented with coffee ground aspirate could be effectively and safely managed in a local setting of Emergency Medicine Ward (EMW).

Method

A retrospective study with data retrieved from all the cases admitted with a diagnosis of coffee ground aspirate or vomiting who were on NG tube feeding during three years before and after EMW was launched. Data including patient demographics, length of stay (LOS), types of pharmaceutical treatment received, need of upper endoscopy, in-hospital death and readmission rate within fourteen days were studied. Patients who were haemodynamically unstable, having melaena on per rectal examination, on warfarin or with underlying gastrointestinal malignancy were excluded.

Results

A total of 223 patients matching the studied criteria were included in the study, with 103 of them being admitted before the opening of EMW. For the 120 cases admitted after EMW was launched, 70 cases were admitted to EMW and 50 admitted to Medical Ward. The LOS for elderly patients on NG tube feeding presented with coffee ground aspirate was significantly shortened after EMW was launched (5.2 days vs. 4.2 days, p=0.046). In-hospital mortality and 14-day readmission rate were similar in the two studied period. Patients admitted to EMW and Medical Ward in the second study period were also analysed. Those admitted to EMW had a shorter LOS than those admitted to Medical ward during the same period (3.4 days vs. 5.3 days, p=0.001).

Conclusion

The establishment of EMW in local setting can achieve a significant reduction in hospital LOS without jeopardizing patient outcome for elderly patients who are on NG tube feeding presenting with coffee ground aspirate.

A Retrospective Study of Geriatric Patients Presenting with Fever to an Accident and Emergency Department in Hong Kong

Objectives

To study the characteristics and outcome of geriatric patients presenting with fever to an emergency department in Hong Kong and to analyse the factors affecting their length of stay.

Methods

Retrospective study. Patients aged ≥65 who complained of fever, or with temperature ≥37.5°C (aural) presenting to the Accident and Emergency Department (AED) of Caritas Medical Centre in Hong Kong from 14 November 2006 to 13 December 2006 were enrolled. The demographic data, clinical information and outcomes were studied. The characteristics of short stay and long stay patients were compared.

Results

There were 370 patients in the study. Their median age was 80. Of these patients, 64.9% were category 3 or above, i.e. urgent, emergent or critical. The most common chief complaints were fever, shortness of breath, dizziness and cough. The admission rate was 81.9%. The median length of stay in hospital was 4.3 days. The most common hospital discharge diagnoses were chest infection, urinary tract infection, and fever with unknown cause. The discharge rate within 48 hours was 24.6%. With further analysis, temperature, walking ability, triage category and neutrophil count were significantly different between short stay (≤48 h) and long stay (>48 h) patients. For those discharged alive either from the AED or ward, 20.1% re-attended the AED within 14 days of discharge, and 17.5% of those previously discharged were admitted again for fever or other problems.

Conclusion

Elders with fever are a major challenge to the AED and health care facilities. The admission rate for this group of patients is usually high. Elders with poor walking ability, high triage category, high temperature and neutrophil count were prone to have longer stay.

Atypical periprosthetic femoral fracture: a case report

We report an 82-year-old woman who underwent fixation with a long-spanning cable-plate for a bisphosphonate-induced Vancouver B1 periprosthetic femoral fracture. Non-union and breakage of the plate occurred at 16 months and necessitated revision surgery using a long-stem femoral prosthesis augmented with a cable-plate construct. Bone union was achieved eventually after 10 months.

Efficacy and safety of hylan G-F 20 injection in treatment of knee osteoarthritis in Chinese patients: results of a prospective, multicentre, longitudinal study

OBJECTIVE

To study the efficacy and safety of single intra-articular injection of 6-mL hylan G-F 20 in Chinese patients with symptomatic knee osteoarthritis.

DESIGN

Prospective case series.

SETTING

Six government hospitals in Hong Kong.

PATIENTS

Patients with primary knee osteoarthritis were recruited from six government hospitals from 1 October 2010 to 31 May 2012. All patients received 6-mL intra-articular injection of hylan G-F 20.

MAIN OUTCOME MEASURES

Pain visual analogue scale, functional visual analogue scale, and 5-point Likert scale on change of pain and function were assessed. Adverse events were checked. Radiographs were taken pre-injection and at 3 months and 1 year.

RESULTS

A total of 110 knees of 95 patients with primary knee osteoarthritis were treated. The mean age of the patients was 62 (standard deviation, 9.8) years. All patients completed 1 year of follow-up. The mean pain visual analogue scale, functional visual analogue scale, and Likert value for pain and function showed statistically significant improvements at 6 weeks, 3 months, 6 months, and 1 year compared with the pre-injection values. No significant correlations were found between changes in visual analogue scale and age, body mass index, pre-injection radiological osteoarthritis severity, serum erythrocyte sedimentation rate, or C-reactive protein. Serial radiographs did not show any changes in the radiological severity of knee osteoarthritis. Overall, 16.4% of the patients experienced mild and self-limiting adverse events.

CONCLUSION

Hylan G-F 20 is a safe and effective therapy to relieve pain and improve function for up to 1 year in Chinese patients with knee osteoarthritis.

A combined method to estimate parameters of the thalamocortical model from a heavily noise-corrupted time series of action potential

A combined method composing of the unscented Kalman filter (UKF) and the synchronization-based method is proposed for estimating electrophysiological variables and parameters of a thalamocortical (TC) neuron model, which is commonly used for studying Parkinson's disease for its relay role of connecting the basal ganglia and the cortex. In this work, we take into account the condition when only the time series of action potential with heavy noise are available. Numerical results demonstrate that not only this method can estimate model parameters from the extracted time series of action potential successfully but also the effect of its estimation is much better than the only use of the UKF or synchronization-based method, with a higher accuracy and a better robustness against noise, especially under the severe noise conditions. Considering the rather important role of TC neuron in the normal and pathological brain functions, the exploration of the method to estimate the critical parameters could have important implications for the study of its nonlinear dynamics and further treatment of Parkinson's disease.

Hyaluronic acid instillation following arthroscopic anterior cruciate ligament reconstruction: a double-blinded, randomised controlled study

PURPOSE

To assess the effect of hyaluronic acid instillation after arthroscopic anterior cruciate ligament (ACL) reconstruction for improving pain, range of movement, and function of the knee.

METHODS

28 men and 4 women underwent arthroscopic ACL reconstruction for isolated ACL rupture (partial or complete) and instability after recreational sports injury 2 to 120 months earlier. They were randomised to undergo arthroscopic ACL reconstruction followed by intra-articular viscoseal instillation (13 men and 3 women) or arthroscopic ACL reconstruction alone (15 men and 1 woman). The knee injury osteoarthritis outcome score (for pain, symptoms, activities of daily living, sport and recreation function, and quality of life), range of movement, knee circumference, and analgesic use were assessed on days -1, 1, and 2, and weeks 2, 6 and 12.

RESULTS

Patient demographics were similar at baseline. At postoperative days 1 and 2, all subscales of the knee injury osteoarthritis outcome score (except for quality of life) were significantly higher in the viscoseal group. At weeks 2, 6, and 12, improvement in both groups equalised. Knee swelling (change in knee circumference) was significantly less in the viscoseal group at days 1 and 2 (p=0.009 and p=0.038, respectively, Mann-Whitney U test). Only one patient in the viscoseal group had a limited range of movement. No patient developed any adverse reaction.

CONCLUSION

Intra-articular viscoseal instillation improved pain control and swelling 2 days after arthroscopic ACL reconstruction.

TENOSYNOVIAL OSTEOCHONDROMATOSIS OF BOTH FLEXOR AND EXTENSOR TENDONS

An unusual case of a 52-year-old woman with tenosynovial osteochondromatosis involving both of the wrist flexor and extensor tendons is reported.

Chaotic phase synchronization in small-world networks of bursting neurons

We investigate the chaotic phase synchronization in a system of coupled bursting neurons in small-world networks. A transition to mutual phase synchronization takes place on the bursting time scale of coupled oscillators, while on the spiking time scale, they behave asynchronously. It is shown that phase synchronization is largely facilitated by a large fraction of shortcuts, but saturates when it exceeds a critical value. We also study the external chaotic phase synchronization of bursting oscillators in the small-world network by a periodic driving signal applied to a single neuron. It is demonstrated that there exists an optimal small-world topology, resulting in the largest peak value of frequency locking interval in the parameter plane, where bursting synchronization is maintained, even with the external driving. The width of this interval increases with the driving amplitude, but decrease rapidly with the network size. We infer that the externally applied driving parameters outside the frequency locking region can effectively suppress pathologically synchronized rhythms of bursting neurons in the brain.

Silver Nitrate Stain Masquerading as an Avulsion Fracture of the Finger

We report a case of silver nitrate stain on the finger that masqueraded as an avulsion fracture on radiograph. Radiopacity in the proximal phalanx was demonstrated on radiograph after topical silver nitrate was applied to achieve haemostasis to a bleeding laceration on that area. The radiopacity was initially diagnosed as an avulsion fracture. The correct diagnosis of radiopacity corresponding to silver nitrate application was confirmed by correlation of physical examination with radiographic finding. The lesion spontaneously resolved with conservative management. The importance of correlating the clinical site of silver nitrate application with radiographic finding for accurate diagnosis and avoidance of unnecessary surgical intervention is emphasized.

Experience of a screening centre for influenza A/H1N1: the first 50 days

BACKGROUND

The authors' emergency department (ED) served as Singapore's screening centre for influenza H1N1 cases. The aims of the study were to describe their screening experience and to compare clinical and laboratory features of H1N1 versus seasonal flu cases.

METHODOLOGY

The authors conducted a prospective observational study on consecutive patients aged 16 years and above presenting to a busy, urban ED for H1N1 screening over 50 days. Clinical, laboratory, radiological and PCR data were collected from the hospital electronic databases. Primary outcomes were proportions of confirmed H1N1 cases and their distribution of clinical, laboratory and radiological features. Secondary outcomes were comparison of clinical and laboratory features of H1N1 versus seasonal flu cases. Data were analysed using descriptive statistics and univariate analysis was used to compare factors between the two groups. A p value <0.05 was considered statistically significant.

RESULTS

1205 patients were screened. 31 (2.6%) and 133 (11%) of them had H1N1 and seasonal flu infections, respectively. The two groups had similar symptoms. There were six clinical and two laboratory features with statistically significant differences between H1N1 and seasonal flu cases. Clinical factors were travel or contact history, median age, respiratory rate, diastolic blood pressure and length of hospital stay. Laboratory factors were median platelet and lymphocyte counts.

CONCLUSIONS

The authors report their experience as the nation's H1N1 screening centre. They identified factors that were different between H1N1 and seasonal flu cases. Future research is needed to elucidate if and how this information can be used as a screening tool for H1N1.

Vibrational resonance in neuron populations

In this paper different topologies of populations of FitzHugh-Nagumo neurons have been introduce to investigate the effect of high-frequency driving on the response of neuron populations to a subthreshold low-frequency signal. We show that optimal amplitude of high-frequency driving enhances the response of neuron populations to a subthreshold low-frequency input and the optimal amplitude dependences on the connection among the neurons. By analyzing several kinds of topology (i.e., random and small world) different behaviors have been observed. Several topologies behave in an optimal way with respect to the range of low-frequency amplitude leading to an improvement in the stimulus response coherence, while others with respect to the maximum values of the performance index. However, the best results in terms of both the suitable amplitude of high-frequency driving and high stimulus response coherence have been obtained when the neurons have been connected in a small-world topology.

Harmonics and intermodulation in subthreshold FitzHugh-Nagumo neuron

Intermodulation and harmonics are important in frequency analysis of nonlinear systems. In neuron research, most investigations are taken in studying synchronization between the external stimuli and the output of neuron, but harmonics and intermodulation are often ignored. In this paper, harmonics and intermodulation of the subthreshold FitzHugh-Nagumo neuron are investigated and their magnitudes are used to predict frequency response of the neuron. Furthermore, through analyzing the magnitudes of harmonics, the intrinsic frequencies of the neuron could be identified.

Comparison of total knee arthroplasty using computer-assisted navigation versus conventional guiding systems: a prospective study

PURPOSE

To compare knee alignments in total knee arthroplasty (TKA) using computer-assisted navigation versus conventional guiding systems.

METHODS

Five men and 49 women aged 49 to 79 years underwent TKA for primary osteoarthritis of the knee with varus deformity. All valgus knees were associated with inflammatory arthritis and thus excluded. Computer-assisted navigation was used for the first 35 TKAs, whereas conventional extramedullary tibial and intramedullary femoral guiding systems were used for the next 35 TKAs. The mechanical axis, coronal tibial and femoral angles, sagittal tibial and femoral angles in the 2 groups were compared.

RESULTS

Sagittal tibial and femoral angles aligned more optimally in TKAs using computer-assisted navigation. In the respective computer-assisted navigation and conventional guiding systems, 33 (94%) and 26 (74%) of the TKAs attained a postoperative mechanical axis of <3 degrees varus/valgus.

CONCLUSION

Computer-assisted navigation gives a more consistent alignment correction and reduces outliers during implant positioning.

Kinetic Monte Carlo simulations compared with continuum models and experimental properties of pattern formation during ion beam sputtering

Kinetic Monte Carlo simulations model the evolution of surfaces during low energy ion bombardment using atomic level mechanisms of defect formation, recombination and surface diffusion. Because the individual kinetic processes are completely determined, the resulting morphological evolution can be directly compared with continuum models based on the same mechanisms. We present results of simulations based on a curvature-dependent sputtering mechanism and diffusion of mobile surface defects. The results are compared with a continuum linear instability model based on the same physical processes. The model predictions are found to be in good agreement with the simulations for predicting the early-stage morphological evolution and the dependence on processing parameters such as the flux and temperature. This confirms that the continuum model provides a reasonable approximation of the surface evolution from multiple interacting surface defects using this model of sputtering. However, comparison with experiments indicates that there are many features of the surface evolution that do not agree with the continuum model or simulations, suggesting that additional mechanisms are required to explain the observed behavior.

Stress-enhanced pattern formation on surfaces during low energy ion bombardment

Ion-induced surface patterns (sputter ripples) are observed to grow more rapidly than predicted by current models, suggesting that additional sources of roughening may be involved. Using a linear stability analysis, we consider the contribution of ion-induced stress in the near surface region to the formation rate of ripples. This leads to a simple model that combines the effects of stress-induced roughening with the curvature-dependent erosion model of Bradley and Harper. The enhanced growth rate observed on Cu surfaces appears to be consistent with the magnitude of stress measured from wafer curvature measurements.

Compositionally modulated ripples induced by sputtering of alloy surfaces

Sputtering of an amorphous or crystalline material by an ion beam often results in the formation of periodic nanoscale ripple patterns on the surface. In this Letter, we show that, in the case of alloy surfaces, the differences in the sputter yields and surface diffusivities of the alloy components will also lead to spontaneous modulations in composition that can be in or out of phase with the ripple topography. The degree of this kinetic alloy decomposition can be altered by varying the flux of the ion beam. In the high-temperature and low-flux regime, the degree of decomposition scales linearly with the ion flux, but it scales inversely with the ion flux in the low-temperature, high-flux regime.

Thumb polydactyly: clinical outcome after reconstruction

PURPOSE

To evaluate clinical and cosmetic outcomes of reconstruction in thumb polydactyly and prognostic value of the Wassel classification.

METHODS

Between 1993 and 2000 inclusive, out of the patients with thumb polydactyly (involving 80 thumbs) operated on, 34 patients (36 thumbs) were available for review and underwent clinical and radiological assessment. Outcomes in terms of the Tada score and complications were recorded.

RESULTS

The mean age of patients at the time of operation was 2.8 (range, 0.6-47) years. The mean follow-up period was 5 (range, 2.4-10) years. According to the Wassel classification, 12 were type-II thumb polydactyly, 3 type-III, 11 type-IV, 6 type-V, one type-VI, and 3 type-VII. There was no perioperative mortality or wound infection. More than 88% of the patients were satisfied or very satisfied with functional and cosmetic outcomes. Postoperative complications such as scar hypertrophy, pulp atrophy, joint deformity, and instability were common but minor. Ridge nail deformity after the Bilhaut Cloquet procedure was amenable to secondary corrective procedures. All types of operated thumb polydactyly achieved similar mean Tada scores (14.7- 16.6 out of 20). The Wassel classification category, age, and surgical procedures were found to have no prognostic value with regard to the Tada score and presence of complications.

CONCLUSION

Surgery on thumb polydactyly is rewarding. The Wassel classification category can be used as a guide for treatment, although it fails to predict the occurrence of postoperative complications or Tada scores. Our patients' results can serve as guidelines of expected outcomes after reconstructive procedures in different sub-types of thumb polydactyly.

Breakage of intramedullary femoral guide rod during total knee arthroplasty: a case report

We report a rare complication during primary total knee arthroplasty. An intramedullary femoral guide rod was broken during insertion. The broken part jammed into the isthmus of the femur. An initial attempt to push the broken rod via the proximal femur by a guide wire to the distal femur was unsuccessful because the broken rod was lodged in the isthmus. Ultimately, the isthmus was opened using a flexible 9-mm end-cutting reamer, and the broken rod was pushed down to the distal femoral entry site in an antegrade fashion under image intensification. Selecting a more medial entry site on the intercondylar notch with a smaller valgus cutting angle and using a shorter guide rod can avoid such a breakage.

Feasibility and accuracy of 64-row MDCT coronary imaging from a centre with early experience: a review and comparison with established centres

The accuracy of multi-detector computed tomographic (MDCI) coronary angiography (CTA) is dependant on image quality as well as the experience of the operator. Established centers have reported negative predictive values of over 95%. The aim of our study was to investigate the accuracy and feasibility of CTA for the assessment of haemodynamically significant coronary stenosis in a center with very early experience (<6 months) utilizing the improved spatial and temporal resolutions of the latest generation 64-row MDCI scanner. One hundred and twenty eight patients (93 male, 35 female; mean age 56.2 +/- 9.5 years) with suspected or known coronary artery disease underwent both CIA and conventional coronary angiographv (CCA). The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values for stenoses > or =50% by CIA compared to CCA were 70%, 97%, 70% and 97% respectively. Evaluation of main and proximal segments in patients with good quality images (78% of patients) produced values of 94%, 95%, 74% and 99% respectively. The improved spatial and temporal resolutions of 64-row MJ) CT provided a high negative predictive value in assessing significant coronary artery stenosis even in a centre with very early experience. However, new centers embarking on CTA might not be able to reproduce the results reported by more experienced centers.

Hemodynamic significance of heart rate in neurally mediated syncope

BACKGROUND

Vasovagal and vasodepressor syncope are used interchangeably in the literature to describe the common faint syndrome, now collectively named neurally mediated syncope. The significance of heart rate (HR) in these reflex-induced reactions remains unclear.

HYPOTHESIS

The study was undertaken to investigate the hemodynamic significance of HR in tilt-induced neurally mediated syncope.

METHODS

In all, 113 patients with syncope of unknown etiology were studied by head-up tilt test with invasive hemodynamic monitoring. Thirty-five patients (15 women, 20 men, age range 21 to 72 years) developed syncope and were enrolled for analysis. The hemodynamic data were compared between patients who developed bradycardia (vasovagal group, n = 15) and those without bradycardia (vasodepressor group, n = 20).

RESULTS

The baseline hemodynamic data (mean +/- standard deviation) and the hemodynamic responses after 10-min headup tilt were similar between patients in the vasovagal and vasodepressor groups. During syncope, patients with vasovagal reaction developed hypotension and paradoxical bradycardia (HR = 52.4 +/- 5.9 beats/min), while patients with vasodepressor reaction developed a precipitous drop in arterial blood pressure with inappropriate HR (105 +/- 21 beats/min) compensation. Patients with vasovagal syncope manifested a significantly lower cardiac index and a significantly higher systemic vascular resistance index than patients with vasodepressor syncope (1.47 +/- 0.29 vs. 1.97 +/- 0.41 1/min/m2, p < 0.001 and 2098 +/- 615 vs. 1573 +/- 353 dynes x s x cm(-5) x m2, p < 0.003, respectively). A positive correlation existed between HR and cardiac index (r = 0.44, p = 0.008) during syncope in the patients studied.

CONCLUSIONS

These findings suggest that the hemodynamic characteristics of vasovagal and vasodepressor reactions are different, and that HR plays a significant role in neurally mediated syncope.

Autotuning positive feedback time delay controller for dead time processes

Biased relay feedback tests are applied to dead time processes to obtain their ultimate gains and ultimate frequencies. First-order process with dead time models are then fitted to the estimated gains and frequencies. A time delay controller that incorporates a simple compensator with a delay element in positive feedback can be derived from the fitted model. The time delay controller gives better performance comparing with classical Ziegler and Nichols tuned PID controller. Experimental study is included to demonstrate the effectiveness of the proposed tuning scheme and the time delay control algorithm.

Leukocyte mitochondria depolarization and apoptosis in advanced heart failure: clinical correlations and effect of therapy

OBJECTIVES

The purpose of this study was to examine the changes in leukocyte mitochondrial transmembrane potential (MTP) and its association with apoptosis in congestive heart failure (CHF).

BACKGROUND

Congestive heart failure is a heterogeneous syndrome with multiple hemodynamic, neuroendocrine and immune abnormalities. Although edematous CHF may be associated with endotoxemia and increased cytokine production, peripheral blood leukocyte functions in advanced CHF remain unclear.

METHODS

Thirty patients with acute decompensated CHF (mean age [+/- SEM] 74.9 +/- 3.1 years) and 20 healthy controls underwent determination of MTP, intracellular oxidants and apoptosis in three subsets of peripheral blood leukocytes. The measurements were repeated after the time of recompensation.

RESULTS

Patients with acute CHF showed marked MTP reduction and increased intracellular oxidant formation in three subsets of leukocytes upon entry into the study. These changes were more prominent in patients with peripheral edema. The decline in MTP was correlated with the severity of the peripheral edema and plasma concentration of cortisol, nitrogen metabolites and tumor necrosis factor-alpha (p < 0.01). After clinical stabilization, MTP gradually recovered. Leukocytes underwent increased propensity of apoptosis one week after the time of recompensation.

CONCLUSIONS

The mitochondrial depolarization and apoptosis of leukocytes in decompensated heart failure suggest that CHF is associated with severity-dependent impairments in leukocyte function. Accentuated hormonal and cytokine abnormalities and increased circulating oxidants may contribute to these changes. Early and aggressive management of advanced heart failure is helpful in the recovery of these immune abnormalities.

Coincidence detection FDG PET in the management of oncological patients: attenuation correction versus non-attenuation correction

The aim of this study was to determine if attenuation correction (AC) in a dual-head, coincidence, positron emission tomography imaging system (Co-PET) improved image quality, lesion detection, patient staging and management of various malignant neoplasms, compared to non-attenuation corrected (NAC) images. Thirty patients with known or suspected malignant neoplasms underwent fluorodeoxyglucose (FDG) Co-PET, which was correlated with histopathology, computed tomography (CT) and other conventional imaging modalities and clinical follow-up. The number and location of FDG avid lesions detected on the AC images and NAC Co-PET images were blindly assessed by two independent observers. Semi-quantitative grading of image clarity and lesion-to-background quality was performed. This revealed markedly improved image clarity and lesion-to-background quality in the AC versus NAC Co-PET images. AC Co-PET was statistically superior to NAC Co-PET in relation to lesion detection (P<0.01) and tumour staging (P<0.01). NAC Co-PET demonstrated 51 of the 65 lesions (78%) detected by AC Co-PET. AC Co-PET altered tumour staging in five additional patients (16%) compared to NAC Co-PET. Management was altered in two of these five patients.

Regulation of ST2L expression on T helper (Th) type 2 cells

T1/ST2L, an IL-1 receptor homologue, is selectively expressed on murine Th2 cells and specific anti-ST2L antibodies can profoundly modulate the Th1/Th2 balance in vivo. Naive CD4+ T cells do not express ST2L but do so on activation with specific antigen in the presence of IL-4 or when stimulated with low doses of antigen in the absence of exogenously added IL-4. Similarly enhanced ST2L expression occurred after stimulation of Th2 cells with antigen or the mitogen ConA in the presence of APC. Restimulation of Th2 cells in the presence of IFN-gamma led to a decreased expression of ST2L to below basal levels. Conversely, Th2 cells cultured with IL-4 led to increased ST2L expression. The reduced expression of ST2L in response to high doses of antigen is also reversed by the neutralization of IFN-gamma. Using an ST2L promoter/luciferase reporter gene construct, we show that the distal but not proximal ST2L promoter is responsible for specific gene expression in Th2 cells. IL-4 enhances, whereas IFN-gamma suppresses ST2L expression via direct modulation of the distal promoter of the ST2L gene. These data provide a mechanistic explanation for the selective expression of ST2L on Th2 cells.

Human IL-18 receptor and ST2L are stable and selective markers for the respective type 1 and type 2 circulating lymphocytes

CD4(+) (Th) and CD8(+) (Tc) T and NK lymphocytes can be divided into type 1 and 2 subsets according to their cytokine secretion profile. Studies on the role of lymphocyte subsets in human diseases have been hampered by the lack of stable surface markers to define them. Recently, we reported that ST2L and IL-18R are stably expressed on murine Th2 and Th1 cells, respectively. In this study, we generated Abs to human homologues of ST2L and IL-18R and tested them against Th1/Th2, Tc1/Tc2, and NK1/NK2 lines and PBMCs from healthy individuals. We show for the first time that ST2L and IL-18R are stable selective cell surface markers for human Th2/Tc2/NK2 and Th1/Tc1/NK1 lymphocytes, respectively. We then investigated PBMCs from HIV-infected patients and HIV-negative individuals, to test whether Abs to these two surface markers could be used directly to monitor lymphocyte subset distribution in human diseases. We found a clear Th1 to Th2 shift in the HIV-infected individuals, thus settling a long-standing controversy and include, for the first time, Tc and NK cells as well. Therefore, these cell surface molecules could serve as important determinants of the immune status of human diseases in general, and thereby could be useful for therapeutic monitoring and intervention.

Enhancement of the anti-herpetic effect of trichosanthin by acyclovir and interferon

Trichosanthin (TCS) is a type I ribosome-inactivating protein that has a wide range of pharmacological activities. The present study investigated the effectiveness of TCS on herpes simplex virus (HSV-1). The anti-viral activity and toxicity of TCS on Vero cells were measured. Results showed that the ED(50), TD(50) and the therapeutic indices were 38.5, 416.5 and 10.9 microg/ml, respectively. Anti-viral activity of TCS was substantially potentiated when it was used in conjunction with other anti-viral agents. The ED(50) of TCS was reduced 125-fold by acyclovir at a concentration of 0.001 microg/ml, which was practically devoid of significant anti-viral activity. Similarly, the ED(50) of TCS was reduced 100-fold by interferon-alpha2a at a concentration of 100 IU/ml. In conclusion, TCS is effective against HSV-1 and other anti-viral agents such as acyclovir or interferon can potentiate its action substantially.

Integrin mobilizes intracellular Ca(2+) in renal vascular smooth muscle cells

Peptides with the Arg-Gly-Asp (RGD) motif induce vasoconstriction in rat afferent arterioles by increasing the intracellular Ca(2+) concentration ([Ca(2+)](i)) in vascular smooth muscle cells (VSMC). This finding suggests that occupancy of integrins on the plasma membrane of VSMC might affect vascular tone. The purpose of this study was to determine whether occupancy of integrins by exogenous RGD peptides initiates intracellular Ca(2+) signaling in cultured renal VSMC. When smooth muscle cells were exposed to 0.1 mM hexapeptide GRGDSP, [Ca(2+)](i) rapidly increased from 91 +/- 4 to 287 +/- 37 nM and then returned to the baseline within 20 s (P < 0.05, 34 cells/5 coverslips). In controls, the hexapeptide GRGESP did not trigger Ca(2+) mobilization. Local application of the GRGDSP induced a regional increase of cytoplasmic [Ca(2+)](i), which propagated as Ca(2+) waves traveling across the cell and induced a rapid elevation of nuclear [Ca(2+)](i). Spontaneous recurrence of smaller-amplitude Ca(2+) waves were found in 20% of cells examined after the initial response to RGD-containing peptides. Blocking dihydropyridine-sensitive Ca(2+) channels with nifedipine or removal of extracellular Ca(2+) did not inhibit the RGD-induced Ca(2+) mobilization. However, pretreatment of 20 microM ryanodine completely eliminated the RGD-induced Ca(2+) mobilization. Anti-beta(1) and anti-beta(3)-integrin antibodies with functional blocking capability simulate the effects of GRGDSP in [Ca(2+)](i). Incubation with anti-beta(1)- or beta(3)-integrin antibodies inhibited the increase in [Ca(2+)](i) induced by GRGDSP. We conclude that exogenous RGD-containing peptides induce release of Ca(2+) from ryanodine-sensitive Ca(2+) stores in renal VSMC via integrins, which can trigger cytoplasmic Ca(2+) waves propagating throughout the cell.

New features of renal lesion induced by stroma free hemoglobin

This study focused on the subacute renal lesions resulting from the infusion of stroma free hemoglobin (SFH), which remains under evaluation as a potential blood substitute despite limited renal toxicity observed in acute infusion. Four groups of rats received different doses of SFH (0.03, 0.48, 0.96, and 1.46 g, respectively) and were monitored, on alternate days, for their glomerular filtration rate over the course of 10 days. Another group of 6 rats receiving 0.96 g SFH was sacrificed at day 10 for examination of renal morphology. The low dose (0.03 g) of SFH infusion did not alter the creatinine clearance (Clcr) over 10 days. The Clcr decreased in rats receiving 0.48 g SFH but fully recovered at day 10. A persistent decrease in Clcr was observed in the groups of rats receiving 0.96 and 1.68 g of SFH. Tubular necrosis was the most prominent renal lesion distributed in the proximal tubules, especially in the convoluted segment of the juxtamedullary nephrons. Pearls' stained cytoplasmic granules and electron-dense lysosomal granules were found in surviving proximal tubules. Necrosis was the predominant mechanism of cell death. This study revealed for the first time proliferation of smooth endoplasmic reticulum in the proximal tubules after SFH treatment, where it appeared as nodular aggregates of tubulovesicular structures. The effect of SFH on the proximal tubule appeared to be a direct toxicity, and this toxicity was shown to be dose dependent. The presence of reversible toxicity indicated that a safety limit dosage for SFH infusion exists and that tolerance dose of SFH can be determined for clinical applications.

Mechanical strain memory in airway smooth muscle

We investigated the effect of a single rapid stretch on poststretch force and myosin phosphorylation in bovine tracheal smooth muscle. When unstimulated muscle strips were stretched from suboptimal length to optimal length (L(o)), poststretch steady-state force was not significantly different from that of unstretched control at L(o). However, when carbachol-activated muscle strips were stretched from suboptimal length to L(o), poststretch force and myosin phosphorylation were lower than control and significantly correlated with initial length. When poststretch muscle strips were allowed to relax for 1 h and then activated by K(+) depolarization, the developed force remained significantly correlated with initial length. When the same strain was applied in 23 increments to minimize peak stress, poststretch force and myosin phosphorylation increased significantly, approaching the levels expected at L(o). Furthermore, poststretch force development increased after each cycle of contraction and relaxation, approaching the control level after four cycles. These results suggest that activated airway smooth muscle cells can retain relatively precise memory of past strain when they are stretched rapidly with high stress.

Trichosanthin interacts with and enters cells via LDL receptor family members

The type-I ribosome-inactivating protein trichosanthin displays selective cytotoxicity, suggesting specific mechanisms for entry into cells. Here we show that trichosanthin binds specifically to the endocytic receptors LRP and megalin, and that binding as well as uptake into cells is inhibited by the receptor-associated protein (RAP). The results suggest that the known abortifacient and renotoxic actions of trichosanthin are caused by LRP-mediated uptake in trophoblasts and megalin-mediated uptake in proximal tubule epithelial cells, respectively.

Engineering of a mini-trichosanthin that has lower antigenicity by deleting its C-terminal amino acid residues

Trichosanthin is a ribosome-inactivating protein that possesses antitumor and antiviral activities. Clinical trials of trichosanthin on AIDS patients, however, elicit anaphylactic reactions. To reduce the antigenicity of trichosanthin as a drug while preserving its biological activity, the C-terminal domain (residues 203 to 247), which contains a putative antigenic site, was systemically deleted. We have found that the minimum length of trichosanthin that can fold into an active conformation is residue 1 to 240. The mini-trichosanthin (C7) generated by deleting the last seven C-terminal amino acid residues has 2.7-fold decrease in antigenicity, 10-fold reduction in in vitro ribosome-inactivation activity, and in vivo cytotoxicity toward K562 cells, and 2-fold reduction in abortificient activity. Structural analyses of C7 indicate decrease in the helix content, increased exposure of Trp192, and lower thermodynamic stability. The deletion of the C-terminal residues (Leu241 to Ala247) probably perturbs local structure of the C-terminal antigenic epitope that results in the decrease in antigenicity and activities of C7.

Planar versus SPET imaging in the assessment of condylar growth

The aim of this study was to compare two methods of quantifying 99Tc(m)-methylene diphosphonate uptake in the mandibular condyle. The study groups consisted of 23 patients with mandibular asymmetry and 16 normal volunteers aged 10-30 years. The accuracy and reproducibility of SPET using condyle-to-clivus ratios was compared with planar analysis using condyle-to-L4 (fourth lumbar vertebra) ratios. Quantitative analysis was correlated with semi-quantitative grading by three observers. Normal ranges for condyle-to-L4 and condyle-to-clivus ratios in individuals aged 11 years or over were determined. These ratios are useful in the serial monitoring of patients with condylar hyperplasia to establish when condylar growth has ceased and hence the type of surgery performed. Visual interpretation of condylar activity should use a combination of planar and SPET images and be performed in conjunction with quantitative analysis. Semi-quantitative grading on SPET images detected more subtle differences in condylar activity than planar images (using quantitative analysis as a standard).

Magnolol attenuates peroxidative damage and improves survival of rats with sepsis

Reactive oxygen species and peroxidative damage are implicated in the pathophysiology of sepsis. Magnolol is a compound extracted from the Chinese medicinal herb Magnolia officinalis and has multiple pharmacological effects, notably antioxidant functions. To determine whether magnolol can modulate the course of sepsis, survival rate and biochemical parameters were analyzed in rats with sepsis with various treatment protocols. Magnolol at doses ranging from 10(-9) g/kg to 10(-5) g/kg was administered either before or after induction of sepsis by cecal ligation and puncture. Magnolol did not modulate the course of sepsis induced by two cecal punctures. When one cecal puncture was performed, a moderately evolving type of sepsis was induced, and the survival rate of affected rats was significantly improved by pretreatment with 10(-7) g/kg magnolol. The beneficial effect was partially retained if magnolol was administered 6 hours after onset of sepsis when a higher dose (10(-5) g/kg) was used. The intensity of lipid peroxidation in plasma, liver, and lung of septic rats was also attenuated in a treatment-dependent manner. Magnolol at this dose range exerted these beneficial effects probably through its antioxidant efficacy. These significant results may suggest magnolol as a candidate agent for the treatment of sepsis.

Retropharyngeal abscess on a Ga-67 scan: a case report

A retropharyngeal abscess is a potentially fatal deep neck infection. Classical symptoms include fever, neck swelling, sore throat, dysphagia, and cervical rigidity. Sometimes small children present with nonspecific symptoms. We report a rare case whereby the Ga-67 citrate scan was the first investigation to reveal an inflammatory process in the retropharyngeal or submastoid region of a 3-year-old child with sepsis. This directed the line of investigation to a more precise anatomic imaging modality, CT scanning, to localize the abscess. With prompt administration of intravenous antibiotics, the child recovered quickly and did not require surgery. The Ga-67 scan is thus a useful screening test to detect inflammatory foci because of its high sensitivity. It is also valuable in the follow-up of the patient's response to therapy.

A proinflammatory role for IL-18 in rheumatoid arthritis

IL-18 is a novel cytokine with pleiotropic activities critical to the development of T-helper 1 (Th1) responses. We detected IL-18 mRNA and protein within rheumatoid arthritis (RA) synovial tissues in significantly higher levels than in osteoarthritis controls. Similarly, IL-18 receptor expression was detected on synovial lymphocytes and macrophages. Together with IL-12 or IL-15, IL-18 induced significant IFN-gamma production by synovial tissues in vitro. IL-18 independently promoted GM-CSF and nitric oxide production, and it induced significant TNF-alpha synthesis by CD14(+) macrophages in synovial cultures; the latter effect was potentiated by IL-12 or IL-15. TNF-alpha and IFN-gamma synthesis was suppressed by IL-10 and TGF-beta. IL-18 production in primary synovial cultures and purified synovial fibroblasts was, in turn, upregulated by TNF-alpha and IL-1beta, suggesting that monokine expression can feed back to promote Th1 cell development in synovial membrane. Finally, IL-18 administration to collagen/incomplete Freund's adjuvant-immunized DBA/1 mice facilitated the development of an erosive, inflammatory arthritis, suggesting that IL-18 can be proinflammatory in vivo. Together, these data indicate that synergistic combinations of IL-18, IL-12, and IL-15 may be of importance in sustaining both Th1 responses and monokine production in RA.

Results of coronary stenting after delayed angioplasty of the culprit vessel in patients with recent myocardial infarction

Little information is available concerning the effect of late coronary stenting in patients with recent myocardial infarction, especially long-term results. We retrospectively reviewed our results of 57 stent placements in 52 consecutive patients who received stents at an infarct-related lesion 24 hr to 30 days after an acute myocardial infarctions (median, 14 days). The average age was 67 years; 90% were male. Two patients who suffered from acute stent thrombosis received revascularization again and two early deaths were due to refractory cardiogenic shock before discharge. Mean patient clinical follow-up was 18.3 +/- 6.5 months. There were 1 subacute stent thrombosis, 1 cardiogenic death, and 10 patients (20.8%) in total suffering from angina class II to IV. Angiographic follow-up was performed in 36 patients (80%) at a mean of 7.5 +/- 3.1 months. Of these 36 patients, only 1 (3% of the total population undergoing follow-up angiography) had reocclusion at follow-up, but restenosis existed in 18 patients (50%). We conclude that there is still relatively high incidence of angiographic recurrence that is often silent in long-term follow-up, though the long-term result of late stenting in recent MI is low incidence of reocclusion.

Lowering of trichosanthin immunogenicity by site-specific coupling to dextran

Trichosanthin is a type I ribosome-inactivating protein possessing a broad spectrum of biological and pharmacological activities. Therapeutic use of this compound is hampered by its immunogenicity. It was shown earlier that coupling of dextran to trichosanthin can increase plasma half-life and reduce antigenicity. However, the site where dextran attaches to trichosanthin cannot be controlled; ideally, it should be at or near the antigenic determinant. The present study attempted to couple dextran to trichosanthin at a potential antigenic site. By site-directed mutagenesis, two sites, R29 and K173, were replaced by cysteine, and dextran was coupled to the newly created cysteine residues. The dextran-trichosanthin complex retained 50% of abortifacient activity and had a mean residence time in rats 27-fold longer than natural trichosanthin. Acute hypersensitivity reaction in guinea pigs was reduced greatly after coupling of K173C (a trichosanthin mutant with lysine-173 replaced by cysteine) to dextran. Compared with natural trichosanthin, dextran-K173C had a decrease in IgG and IgE response, whereas the coupling of R29C (a trichosanthin mutant with arginine-29 replaced by cysteine) to dextran did not show significant reduction of immunogenicity. This suggests that K173 but not R29 is located at or near an antigenic determinant. This study has demonstrated an alternative approach for mapping of antigenic determinants. The information obtained is also useful in producing an improved trichosanthin derivative for therapeutic use.