Comparing the performance of ChatGPT GPT-4, Bard, and Llama-2 in the Taiwan Psychiatric Licensing Examination and in differential diagnosis with multi-center psychiatrists

AIM

Large language models (LLMs) have been suggested to play a role in medical education and medical practice. However, the potential of their application in the psychiatric domain has not been well-studied.

METHOD

In the first step, we compared the performance of ChatGPT GPT-4, Bard, and Llama-2 in the 2022 Taiwan Psychiatric Licensing Examination conducted in traditional Mandarin. In the second step, we compared the scores of these three LLMs with those of 24 experienced psychiatrists in 10 advanced clinical scenario questions designed for psychiatric differential diagnosis.

RESULT

Only GPT-4 passed the 2022 Taiwan Psychiatric Licensing Examination (scoring 69 and ≥ 60 being considered a passing grade), while Bard scored 36 and Llama-2 scored 25. GPT-4 outperformed Bard and Llama-2, especially in the areas of 'Pathophysiology & Epidemiology' (χ2  = 22.4, P < 0.001) and 'Psychopharmacology & Other therapies' (χ2  = 15.8, P < 0.001). In the differential diagnosis, the mean score of the 24 experienced psychiatrists (mean 6.1, standard deviation 1.9) was higher than that of GPT-4 (5), Bard (3), and Llama-2 (1).

CONCLUSION

Compared to Bard and Llama-2, GPT-4 demonstrated superior abilities in identifying psychiatric symptoms and making clinical judgments. Besides, GPT-4's ability for differential diagnosis closely approached that of the experienced psychiatrists. GPT-4 revealed a promising potential as a valuable tool in psychiatric practice among the three LLMs.

[Research advances on the mechanism of Wnt/β-catenin signaling pathway in body surface wound healing]

Wound healing is a slow and complex biological process, including inflammatory reaction, cell proliferation, cell differentiation, cell migration, angiogenesis, extracellular matrix deposition, tissue remodeling, and so on. Wnt signaling pathway can be divided into classical pathway and non-classical pathway. Wnt classical pathway, also known as Wnt/β-catenin signaling pathway, plays an important role in cell differentiation, cell migration, and maintenance of tissue homeostasis. Many inflammatory factors and growth factors are involved in the upstream regulation of this pathway. The activation of Wnt/β-catenin signaling pathway plays an important role in the occurrence, development, regeneration, repair and related treatment of skin wounds. This article review the relationship between Wnt/β-catenin signaling pathway and wound healing, meanwhile summarizes its effects on important processes of wound healing, such as inflammation, cell proliferation, angiogenesis, hair follicle regeneration, and skin fibrosis, as well as the role of inhibitors of Wnt signaling pathway in wound healing.

Identification of Genetic Variations in the NAD-Related Pathways for Patients with Major Depressive Disorder: A Case-Control Study in Taiwan

Background and Objectives: Nicotinamide adenine dinucleotide (NAD) is an important coenzyme in various physiological processes, including sirtuins (SIRTs) and kynurenine pathway (KP). Previous studies have shown that lower NAD levels can be indicative of increased risks of cancer and psychiatric disorders. However, there has been no prior study exploring the link between NAD homeostasis and psychiatric disorders from a genetic perspective. Therefore, we aimed to investigate the association of genetic polymorphism in the pathways of NAD biosynthesis with major depressive disorder (MDD). Methods: A total of 317 patients were included in the case group and were compared with sex-matched control group of 1268 participants (1:4 ratio) from Taiwan Biobank (TWB). All subjects in the control group were over 65 years old, which is well past the average age of onset of MDD. Genomic DNA extracted from patients' blood buffy coat was analyzed using the Affymetrix TWB array. Full-model tests were conducted for the analysis of single nucleotide polymorphism (SNPs) in all candidate genes. We focused on genes within the NAD-related candidate pathways, including 15 in KP, 12 in nicotinate metabolism, 7 in SIRTs, and 19 in aldehyde dehydrogenases (ALDHs). A total of 508 SNPs were analyzed in this study. After significant SNPs were determined, 5000 genome-wide max(T) permutations were performed in Plink. Finally, we built a predictive model with logistic regression and assessed the interactions of SNPs with the haplotype association tests. Results: We found three SNPs that were significantly associated with MDD in our NAD-related candidate pathways, one within the KP (rs12622574 in ACMSD) and two within the nicotinate metabolism (rs28532698 in BST1 and rs3733593 in CD38). The observed association with MDD was significant in the dominant model of inheritance with marital status, education level, and body mass index (BMI) adjusted as covariates. Lastly, in haplotype analysis, the three associated SNPs consisted of one haploblock in ACMSD, four haploblocks in BST1, and two haploblocks in CD38. Conclusions: This study provides the first evidence that genetic variations involved in NAD homeostasis in the KP and nicotinate metabolism may be associated with the occurrence of MDD.

Kawasaki disease in childhood and psychiatric disorders: A population-based case-control prospective study in Taiwan

BACKGROUND

Kawasaki disease (KD) is a common childhood acute inflammatory disease and potentially triggers a chronic inflammation. Although some researches have investigated neurodevelopmental consequences following KD, the findings have been inconsistent. This is the first population-based study targeted on KD and common psychiatric disorders.

OBJECTIVES

We aimed to investigate the association between KD and psychiatric disorders and hypothesized that standard anti-inflammatory treatment by intravenous immunoglobulin (IVIG) may protect against development of psychiatric disorders.

METHOD

We retrieved data from Taiwan's National Health Insurance Research database (NHIRD). Patients (n = 282,513) with psychiatric disorders (the case group) during 1997-2013 were included, and the control group was matched with age, sex, income and urbanization (1:1). We calculated the prevalence of KD in both groups and estimated odd ratios (ORs) and 95% confidence intervals (CIs) in the subgroup analyses for KD in conditions of age, severity, and common psychiatric comorbidity.

RESULTS

Numbers of patients with KD were 460 in the cases and 380 in the controls (p = .006), and the crude OR of KD was 1.21 times greater (95% CI = 1.06-1.39, p = .006) in the case than the control groups. KD patients without IVIG treatment (n = 126) were higher in the cases than those in the controls (n = 54), with the OR of 2.33 (95% CI = 1.70-3.21, p < .0001). Subgroup analyses showed that KD survivors were at significant risk for autism spectrum disorders (ASD) (OR = 2.15, 95% CI = 1.27-3.65; p = .005) and attention deficit and hyperactivity disorders (ADHD) (OR = 1.19, 95% CI = 1.02-1.39; p = 0.03), and a trend of increased risk for anxiety disorders (OR = 1.36, 95%CI = 0.99-1.86; p = 0.05).

CONCLUSIONS

Patients with KD were more likely to have comorbid psychiatric disorders, including ASD and ADHD. Moreover, anti-inflammatory treatment with IVIG may have potential prophylactic effects against the development of psychiatric disorders.

Genetic Variations of Ionotropic Glutamate Receptor Pathways on Interferon-α-induced Depression in Patients with Hepatitis C Viral Infection

IMPORTANCE

The most supportive evidence of the inflammation theory of depression is that up to one-third of patients with Hepatitis C virus infection (HCV) develop clinical depressive episodes during interferon-α (IFN-α) therapy. As glutamate-mediated excitotoxicity has been found to be a consequence of excessive inflammation and a pathogenic mechanism of depression, it is plausible to investigate genes on ionotropic glutamate receptor pathways.

OBJECTIVE

To identify the at-risk genetic variations on ionotropic glutamate receptor pathways for interferon-α-induced depression.

METHOD

We assessed 291 patients with chronic HCV undergoing IFN-α therapy and analyzed the single nucleotide polymorphisms (SNPs) in genes related to ionotropic glutamate receptors in this prospective case-control study. Patients who developed IFN-α-induced depression anytime during the treatment were defined as the case group, while those who did not were defined as the control group. Genomic DNA was extracted from peripheral blood and analyzed by Affymetrix TWB array. Allelic and haplotype association tests were conducted using χ2 tests to assess the difference in allele and haplotype frequencies between cases and controls. Additionally, we performed 5000 permutations to control gene-wide family-wise error rates and create empirical p-values. Stratified analyses were then done to control for confounders and adjust odds ratios for our significant SNPs. We also did an additional stratified analysis to re-assess genes with near-significant SNPs (empirical p-value=0.05-0.10), employing Bonferroni correction with the effective number of independent tests to control gene-wide family-wise error rates.

RESULTS

The minor and major allele frequencies of rs7542 (empirical p-value=0.0310) in MAPK3, rs3026685 (empirical p-value=0.0378) in PICK1, rs56005409 (empirical p-value=0.0332) in PRKCA, rs12914792 (empirical p-value=0.0096), rs17245773 (empirical p-value=0.0340) in RASGRF1, and rs78387863 (empirical p-value=0.0086), rs74365480 (empirical p-value=0.0200) in RASGRF2 were found significantly different between cases and controls. Haplotype association tests also revealed one significant haplotype in PRKCA (empirical p-value=0.0200) and one in RASGRF1 (empirical p-value=0.0048). Stratified analyses showed no signs of confounders for most of our significant SNPs, except for rs78387863 in RASGRF2. After a re-assessment of our near-significant genes by stratified analyses, two SNPs in GRIN2B turned significant.

CONCLUSIONS

This study provided supportive evidence of the involvement of the RAS/RAF/mitogen-activated protein kinase (MAPK) signaling pathway and glutamate ionotropic receptor AMPA type subunit 2(GluR2) transportation in the pathogenesis of IFN-α-induced depression.

Methods and clinical outcomes of in situ fenestration for aortic arch revascularization during thoracic endovascular aortic repair

OBJECTIVE

Despite endovascular advances in fenestrated and branched devices, thoracic endovascular aortic repair (TEVAR) for arch pathologies remains challenging. The aim of this study was to provide a contemporary review on the current evidence for in situ fenestration during TEVAR and to evaluate its short- and mid-term clinical outcome in the management of arch pathology.

METHODS

A systematic literature review on in situ fenestration of thoracic aortic stent-graft from January 2003 to September 2018 was performed under the instruction of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement.

RESULTS

Our initial search yielded 169 studies, of which 21 articles were relevant to the topic and were finally included. One hundred and forty-five in situ fenestration procedures in 99 patients were reviewed, involving 25 innominate arteries (17%), 33 left common carotid arteries (23%) and 87 left subclavian arteries (60%). Twelve patients (12/99, 12%) had two-vessel fenestration and three-vessel fenestration was performed in 17 patients (17/99, 17%). Technical success was achieved in 136 arteries (136/145, 93%). Talent/Valiant with monofilament twill woven polyester fabric was the most common (50/99, 51%) stent-graft used for fenestration. Three methods reported for in situ fenestration were needle, laser and radiofrequency. Needle was the most frequently used device for fenestration, which was performed in 60 patients (60/99, 61%). Three patients (3/99, 3%) died with 30 days, none were in situ fenestration TEVAR procedure-related. Perioperative complications including one (1%) retrograde type A aortic dissection, two (2%) type II endoleaks, and three (3%) strokes were reported. The pooled estimate for overall technical success, perioperative mortality and stroke was 88.3% (95% CI, 78.6%-93.9%), 5.9% (95% CI, 2.5%-13.4%) and 9.5% (95% CI, 4.1%-20.6%), respectively. Four patients (4/96, 4%) died during follow-up, none were aortic-related. All the fenestration bridging stents were reportedly patent, with only 1 (1/96, 1%) asymptomatic left subclavian stent stenosis. Two patients (2/96, 2%) with type II endoleak from left subclavian artery required secondary intervention.

CONCLUSION

In situ fenestration appeared to be a feasible and effective method to extend proximal landing zone during TEVAR. It had an acceptable short-term result with high technical success and low fenestration related morbidity. Long-term durability data were lacking, and there was no high level evidence to recommend the routine use of in situ fenestration TEVAR for the management of arch pathology.

Delayed open conversion after endovascular aortic repair

AIM

We present the clinical outcomes of patients who underwent delayed (>30 days) open surgical repair after endovascular aortic aneurysm repair.

METHODS

All patients receiving delayed open repair of infrarenal and juxtarenal aortic aneurysms after endovascular repair from July 2001 to December 2017 were retrospectively reviewed. Patients' baseline characteristics, indications for delayed open conversion, and time between endovascular repair and open conversion are described. Early outcomes included operative approach, morbidity, and mortality. Midterm outcomes included survival.

RESULTS

Twenty-two (3.3%) of 667 patients with prior infrarenal endovascular aortic aneurysm repair had delayed open conversion (20 elective and 2 emergency). The time from endovascular repair to open conversion was 60 ± 36 months. The indications were 6 (27%) type Ia endoleaks, 6 (27%) type II endoleaks with enlarging sac size, 2 (9%) endotensions, 7 (32%) unknown types of endoleak, and 1 (5%) graft infection. The 7 minutes unknown endoleaks were confirmed as lumbar leaks in 4 cases and fabric leaks in 3. Operative time was 222 ± 48 min with blood loss of 2211 ± 2057 mL. Hospital stay after conversion was 12 ± 8 days. There was no 30-day mortality. Estimated survival rates were 96%, 91%, 86%, 79% and 57% at 1, 2, 3, 4, and 5 years postoperatively.

CONCLUSION

Delayed conversion to open surgery after endovascular aortic aneurysm repair by endograft explantation appears to be safe with good short- and mid-term outcomes. With careful preoperative assessment, open conversion remained a realistic and viable option in patients with failed endovascular treatment.

Arch branch endografts for arch aneurysms associated with bovine anomaly

Bovine aortic arch is known to be associated with an increased rate of aortic arch expansion. The most frequently observed human variant of bovine aortic arch is a common origin of the innominate trunk and left common carotid artery. This is a report of two patients who had successful custom-made arch branch endograft treatment for an arch aneurysm associated with bovine arch anomaly. Modular endovascular repair of aortic arch aneurysms using an inner-branched device adds to the armamentarium of treatment options, and is a minimally invasive management modality without the need for sternotomy or intraoperative extracorporeal bypass.

A report of three families with FBN1-related acromelic dysplasias and review of literature for genotype-phenotype correlation in geleophysic dysplasia

Acromelic dysplasia is a heterogeneous group of rare skeletal dysplasias characterized by distal limb shortening. Weill-Marchesani syndrome (WMS), Geleophysic dysplasia (GD) and Acromicric dysplasia (AD) are clinically distinct entities within this group of disorders and are characterized by short stature, short hands, stiff joints, skin thickening, facial anomalies, normal intelligence and skeletal abnormalities. Mutations of the Fibrillin-1 (FBN1) gene have been reported to cause AD, GD and related phenotypes. We reported three families with acromelic short stature. FBN1 analysis showed that all affected individuals carry a heterozygous missense mutation c.5284G > A (p.Gly1762Ser) in exon 42 of the FBN1 gene. This mutation was previously reported to be associated with GD. We reviewed the literature and compared the clinical features of the patients with FBN1 mutations to those with A Distintegrin And Metalloproteinase with Thrombospondin repeats-like 2 gene (ADAMTSL2) mutations. We found that tip-toeing gait, long flat philtrum and thin upper upper lip were more consistently found in GD patients with ADAMTSL2 mutations than in those with FBN1 mutations. The results have shed some light on the phenotype-genotype correlation in this group of skeletal disorders. A large scale study involving multidisciplinary collaboration would be needed to consolidate our findings.

Spontaneous Retroperitoneal Hematoma Simulating Ruptured Infrarenal Aortic Aneurysm in a Patient with End-Stage Renal Disease

We reported a case of spontaneous retroperitoneal hematoma (SRH) simulating a ruptured infrarenal aortic aneurysm. A 72-year-old man with a history of infrarenal aortic aneurysm and end-stage renal disease on hemodialysis presented with malaise and nonspecific central abdominal pain and left loin discomfort. An emergency computed tomography scan showed a large retroperitoneal hematoma and clinical suspicion of ruptured infrarenal aortic aneurysm. However, the hematoma was discontinuous with the aneurysm sac and raised the clinical suspicion on dual pathology. The SRH was treated conservatively with transfusion of blood products, and the aneurysm was treated with nonemergency endovascular repair electively. This case demonstrates the importance of recognizing different clinical and radiological characteristics and be aware of dual pathology.

Clinical and Hemodynamic Outcomes in Patients with Chronic Venous Insufficiency After Oral Micronized Flavonoid Therapy

The aim of this study was to prospectively investigate the clinical efficacy of Daflon therapy in patients with mild to moderate chronic venous insufficiency (CVI) (clinical class 1-4) and to assess the changes in venous hemodynamics by using air plethysmography (APG). Fifty-six limbs in 28 patients were studied. They all had primary venous insufficiency with no venous obstruction, and mixed deep and superficial venous incompetence was found in 64% of the limbs. There was a significant decrease in symptom score for swelling and heaviness after 6 months of Daflon therapy. The symptom score for cramps also showed improvement though it did not reach statistical significance. Pain was significantly reduced with a mean pain score of 21.8 + 19.3% before comparing to 10.4 ±20.2% after 6 months of Daflon therapy (p<0.01). This was also associated with a decrease in mean calf circumference from 37.0 ±4.3 to 36.4 ±4.3 cm (p<0.001). There was no significant change in the venous filling index (VFI), ejection fraction (EF), and residual volume fraction (RVF) before and after 6 months of Daflon therapy (VFI: 3.7 ±3.5 vs 3.4 ±2.5 mL/s, EF: 54.5 ±15.9% vs 57.7 +19.7%, RVF: 41.4 ±19.2% vs 39.4 ±24.2%). The clinical improvement without associated changes in venous hemodynamics as measured by APG suggests that Daflon mainly works by modifying the microcirculatory environment not detected by APG and this microcirculatory change is associated with clinical improvement. In this regard, Daflon would be especially useful for symptomatic relief in patients with functional venous insufficiency who do not have clinical evidence of varicose veins but suffer from symptoms of venous insufficiency.

Surgical management of carotid body tumor – Is Shamblin classification sufficient to predict surgical outcome?

Background

The study aims to conduct a review of the surgical management of carotid body tumor.

Methods

Consecutive patients with CBT who received surgical interventions from January 1994 to January 2014 at our institution were reviewed. Clinical, operative, pathological and follow up information were reported.

Results

Twenty patients (four males; median age was 36) with 21 CBT operations were recorded during the period. One patient undertook sequential operations for bilateral CBTs. Patients had 19 neck mass, 1 incidental finding and 1 facial nerve palsy. Six CBTs (28.6%) were Shamblin class I, ten (47.6%) were class II and five (23.8%) were class III. Nine CBTs had preoperative conjunctive embolization. Two operations required internal carotid artery resection and reconstruction. Four patients received subtotal resections, while 17 achieved complete resection. Complications included two major strokes, three hoarse voice and two Horner’s syndrome. Shamblin class was significant predictor of operative time, blood loss, and whether complete resection accomplished, but could not predict postoperative complication. With median follow up period of 94 months, there was no tumor recurrence found in those had complete resection.

Conclusions

This small cohort showed that Shamblin class was significant in predicting technical difficulties but could not predict occurrence of complications.

The effect of anticonvulsant use on bone mineral density in non-ambulatory children with cerebral palsy

INTRODUCTION

Studies showed that use of anticonvulsants (antiepileptic drugs) might be associated with reduced bone mineral density. The primary objective of this study was to evaluate the effect of anticonvulsants on bone mineral density in non-ambulatory children with cerebral palsy. The secondary objective was to identify their risk factors for low bone mineral density.

METHODS

This case series with internal comparisons was conducted in a paediatric residential rehabilitation centre in Hong Kong. Overall, 32 patients were enrolled. The study group comprised 18 patients (6 males, 12 females) aged 5.0 to 19.5 years (mean ± standard deviation, 13.8 ± 4.7 years); all were prescribed anticonvulsant therapy for more than 2 years. The comparison group comprised 14 patients (6 males, 8 females) aged 7.0 to 19.1 years (mean, 16.4 ± 3.0 years) who were concomitant non-ambulatory residents with cerebral palsy and were not prescribed any anticonvulsant therapy prior to study recruitment. Patients underwent a physical examination, blood tests, nutritional assessment, and dual-energy X-ray absorptiometry scan of the total body less head. Z-scores were calculated.

RESULTS

There was no significant difference in Z-scores of total body less head between groups. Among children with low bone mineral density (Z-scores ≤-2.0) and normal bone mineral density, multivariate analysis revealed that higher weight-for-age Z-score (adjusted odds ratio=0.015) and presence of puberty (adjusted odds ratio=0.027) were independent factors for bone mineral density improvement. Hosmer-Lemeshow goodness of fit test (P=0.315) was not significant. Nagelkerke R(2) was 0.677, signifying a relatively well-fitting model.

CONCLUSION

There was no evidence that anticonvulsant therapy has any detrimental effect on bone mineral density in non-ambulatory children with cerebral palsy. A low weight-for-age Z-score was associated with low bone mineral density. Early nutritional intervention to optimise body weight may help to increase bone mineral density.

Influence of meteorological factors on acute aortic events in a subtropical territory

BACKGROUND/OBJECTIVE

This study aims to examine the relationship between weather changes and acute aortic events in a subtropical territory.

METHODS

A linear regression analysis was performed in a pan-territory epidemiological survey for a period of 10 years on the impacts of meteorological factors (ambient temperature, atmospheric pressure, relative humidity, amount of cloud, rainfall, number of lightning strikes, presence of typhoon, and thunderstorm warning) on the daily incidences of acute aortic dissections and ruptured aortic aneurysms. Meteorological variables were retrieved on a daily basis from a well-established observatory, and the daily incidences of aortic dissections and rupture of aortic aneurysms were retrieved from the Clinical Data Analysis and Reporting System.

RESULTS

During the study period (January 2005 to December 2014), 3878 patients were identified as having acute aortic dissections, and 1174 patients had ruptured aortic aneurysms. Corresponding averaged daily incidences were 1.06 and 0.32, respectively. The incidences of aortic dissection and ruptured aortic aneurysm in a day could be predicted by ambient temperature in degrees Celsius using the following linear regression models: (1) incidence of aortic dissection = 1.548 - 0.021 × temperature; (2) incidence of ruptured aortic aneurysm = 0.564 - 0.010 × temperature. In addition, both high atmospheric pressure and absence of thunderstorm warning are positively associated with more aortic dissections. For rupture of aortic aneurysms, high atmospheric pressure and low relative humidity were positive predictors. In multiple regression analysis, however, ambient temperature was the only significant predictor for both acute aortic dissections and ruptured aortic aneurysms.

CONCLUSION

This is the first pan-territory study to show an attributable effect of ambient temperature on acute aortic events. This paper confirms that even in a subtropical country, meteorological variables were important factors influencing acute aortic events.

A pilot study on low-density lipoprotein receptor-related protein-1 in Chinese patients with abdominal aortic aneurysm

OBJECTIVE

There are no published data on the expression of low-density lipoprotein receptor-related protein 1 (LRP1) in human aortic tissues with abdominal aortic aneurysm (AAA), although some researchers have suggested that LRP1 may be a crucial regulator in the pathogenesis of AAA. The aim of this pilot study is to investigate LRP1 expression in aortic tissues from Chinese patients with AAA compared with normal control tissues.

MATERIALS AND METHODS

This study used human abdominal aortic tissues with or without AAA as a research model. Aneurysmal abdominal aortas were collected from Chinese patients with AAA (n = 12) during open surgical aneurysmal repair at our institution, and normal control non-aneurysmal abdominal aortas were collected from Chinese healthy organ donors (n = 12) during organ transplantation. Protein expression of LRP1 was analyzed by western blotting and immunohistochemistry.

RESULTS

LRP1 protein expression was significantly lower in AAA (mean LRP1AAA/LRP1(Normal Control) = 0.51 ± 0.28) than in normal control aortic tissues (mean LRP1(Normal Control)/LRP1(Normal Control) = 1 ± 0.18) in our small sample cohort (p < .001). No significant correlation was shown between LRP1 protein expression and the size of AAA (p > .05).

CONCLUSIONS

Our pilot result suggests that a reduction in LRP1 protein expression may be associated with aneurysm progression.

Successful endovascular management of giant splenic artery aneurysms

Giant pseudoaneurysms of the splenic artery, with a diameter of 5 cm or more, are rare surgical emergencies, and conventional open surgery usually involves splenectomy. The aim of this study is to report two cases from our institution and to review the world's literature on successful endovascular treatment of patients with giant splenic artery pseudoaneurysms. A retrospective review of a prospectively entered departmental computerized database was performed for the two patients from our institution. Articles were searched electronically from PubMed and Medline, using the terms 'giant splenic artery', 'endovascular' and 'embolization'; and relevant cases were reviewed from the world's literature. We hereby report two patients with giant splenic artery pseudoaneurysms who were treated successfully with endovascular procedures. In addition to the two patients from our institution, there were five patients with giant splenic artery pseudoaneurysms in the published literature who underwent successful endovascular management. The first patient of our series had the largest pseudoaneursym size of 7.2 × 8.1 cm, which is the largest documented pseudoaneursym in the current literature. We report two cases of giant splenic artery pseudoaneurysm with one being the largest pseudoaneurysm treated with endovascular technique in the current literature. Endovascular coil embolization of main trunk of splenic artery is less invasive than open surgical treatment for giant splenic artery pseudoaneurysm, and circumvents the problem of difficult exposure, especially in those patients with significant co-morbidity.

Successful carotid endarterectomy in a patient with an aberrant branch from the common carotid artery

We report a patient who had an 80% asymptomatic stenosis in the distal right common carotid artery with an incidental finding of an aberrant branch arising from the right common carotid artery. He underwent an elective right carotid endarterectomy with an uneventful recovery. This is the first case in the literature of a successful endarterectomy in a patient with a common carotid anomaly and it emphasises the importance of careful dissection for unexpected anatomy.

Successful emergency endovascular treatment of juxtarenal and infrarental mycotic aortic aneurysms in patients with small diameter aortae using Cook(®) Zenith ESLE Stentgrafts

BACKGROUND

Endovascular repair of mycotic aneurysm is an alternative to open repair if the patho-anatomy is suitable. The aortic size above and below the mycotic aneurysm may be small.

METHODS

A retrospective review was made of prospectively collected departmental computerised database.

RESULTS

Three oriental patients with juxta- and infra-renal mycotic aortic aneurysms with a small aortic diameter of 17 mm to 18 mm underwent successful emergency endovascular treatment using Cook(®) Zenith ESLE stentgrafts. These are ancillary devices aimed at iliac extensions usually.

CONCLUSION

This is to our knowledge the first case series of Cook(®) Zenith ESLE iliac component endografts for the treatment of aortic mycotic aneurysms with small aortae, and short- and mid-term results are encouraging.

Vitamin D status and peripheral arterial disease: evidence so far

Background

Vitamin D deficiency has recently been implicated as a contributory factor in the development of peripheral arterial disease (PAD).

Methods

A review of the published literature on PAD and vitamin D was undertaken using Medline, PubMed, and Embase, and cross-referenced. All relevant published papers on the subject were reviewed.

Results

Published studies have shown that there is a significant association between vitamin D and PAD. Populations with lower vitamin D levels are more likely to develop PAD in a graded manner. Higher amputation rates are also observed among patients with PAD and lower vitamin D levels. In addition, vitamin D deficiency is significantly associated with increased risk of cardiovascular adverse events. This was also observed in the mouse model where low vitamin D led to the development of atherosclerosis.

Conclusion

This study shows that vitamin D deficiency could be an independent risk factor for the development of PAD and that this risk factor is easily correctable. Further studies should look into the effects of vitamin D supplementation in patients with PAD.

Endovascular infrarenal aneurysm repair in patients with horseshoe kidneys: case series and literature review

Horseshoe kidney may cause technical and access problems during open aortic aneurysm repair. The aim of this study is to report two cases from our institution and to review the world's literature on successful endovascular infrarenal aneurysm repair in patients with horseshoe kidneys. A retrospective review of a prospectively entered departmental computerized database was performed for the two patients from our institution. Articles were searched electronically from PubMed and Medline, using the terms ‘horseshoe kidney’ and ‘aneurysm’. Endovascular cases were reviewed from the world's literature. In addition to the two patients from our institution, there were 19 patients with infrarenal aneurysms and horseshoe kidneys in published literature who underwent successful endovascular aneurysm repair. The occlusion of lower-pole or accessory renal arteries does not seem to cause significant endoleak or renal impairment in the long run. In conclusion, our experience and current literature seem to suggest that endovascular repair of infrarenal aortic aneurysms for patients with horseshoe kidneys is safe. Renal impairment will depend on the area of kidney perfused by the accessory renal arteries. The endovascular treatment option is less invasive than open repair, and circumvents the problem of difficult exposure, especially in those patients with significant co-morbidity.

Drug-eluting stents and balloons in peripheral arterial disease: evidence so far

Restenosis by myointimal hyperplasia after peripheral arterial angioplasty or stenting is a major problem limiting its long-term efficiency and patency, and may lead to recurrent symptoms. Drug-eluting devices which inhibit the proliferation of neo-intimal growth of vascular smooth muscle cells may prevent restenosis. The aim of this article is to examine the evidence in published literature on the use of drug-eluting devices in the treatment of peripheral arterial diseases. A systematic literature review was undertaken of all published literature on this subject using Medline and cross-referenced. All published relevant articles on the use of drug-eluting stents and balloons in peripheral arterial disease were used. Cochrane Central Register of Controlled Trials and electronic databases were also searched for on-going studies. Published results from randomised studies such as the SIROCCO I and II Trials and the THUNDER study, together with single cohort studies, are now available. There are on-going studies comparing drug-eluting and non-drug-eluting devices. Evidence from the published literature suggests that drug-eluting stents and balloons are safe and effective in preventing restenosis after peripheral angioplasty. However, drug-eluting devices are more expensive and many are limited to single-use only. It is anticipated that results from all the on-going studies may allow a meta-analysis to show whether these preliminary data can translate into a clinically applicable cost-effective strategy in combating restenosis after peripheral angioplasty or stenting.

Tender Inflammatory Infrarenal Aortic Aneurysm Simulating Acute Rupture

Even with multislice computed tomography, it may be difficult to differentiate contained ruptured or leaking atherosclerotic aneurysm from a tender inflammatory aneurysm. The decision for early intervention is based on clinical judgment. We describe successful open graft repair of a tender inflammatory infrarenal abdominal aortic aneurysm simulating acute rupture in a 63-year-old man.

Delayed presentation of popliteal pseudo-aneurysm following soccer football injury

Development of pseudo-aneurysm of the popliteal artery usually results from trauma, infection, or iatrogenic causes after orthopedic operations. This is to our knowledge the first reported case in the world's literature of a delayed presentation of a large above-knee popliteal artery pseudo-aneurysm following a soccer football injury. The pseudo-aneurysm severely compressed the native artery, and open exploration with surgical vein-patch repair of the artery was chosen in preference to endovascular stent-graft in view of the compressive symptoms and large size of the chronic pseudo-aneurysm. This case highlights the importance of imaging such as duplex ultrasound, computed tomography, or magnetic resonance angiography if symptoms persist after sports injury.

Perioperative use of statins in noncardiac surgery

BACKGROUND

Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) can significantly decrease cardiovascular mortality and morbidity, irrespective of the patients' cholesterol status. This paper reviews the effects of perioperative statin therapy in patients undergoing noncardiac surgery.

METHOD

A systematic literature review was undertaken of all published literature on this subject using Medline and cross-referenced. All published relevant papers on the perioperative use of statins were used.

RESULTS

Perioperative statin therapy is associated with a lower perioperative morbidity and mortality in patients undergoing elective or emergency surgery. The effects are due to a combination of lipid-lowering and pleiotropic properties of statins.

CONCLUSION

Ideally a large scale multi-centre randomized controlled trial of perioperative statin therapy should be performed but this may be difficult to conduct since there is already overwhelming evidence in the literature to suggest perioperative cardiovascular protective properties. Statins may still be under-prescribed in surgical patients.

A retrospective survey of attitudes toward acceptance of peritoneal dialysis in Chinese end-stage renal failure patients in Hong Kong--from a cultural point of view

OBJECTIVE

We undertook to study the attitudes toward dialysis of patients approaching end-stage renal failure and to analyze those attitudes from a cultural perspective.

SETTING

The study was performed in the pre-dialysis clinic of a tertiary referral renal center.

PATIENTS

All patients of Chinese ethnic origin seen in the pre-dialysis clinic from 1995 to 2000 for assessment of dialysis therapy were included.

METHOD

We performed a retrospective analysis of patient records with regard to attitudes of the patients toward dialysis, reasons for those attitudes, and factors that could lead to a subsequent change in attitude.

RESULTS

We assessed 462 patients over the 6-year period. Their mean age was 65.5 +/- 13.3 years, and 43.9% of the patients had diabetes. Peritoneal dialysis (PD) was offered to 74% of the patients, and hemodialysis (HD) to 3.9%. Among the patients offered PD, only 44% accepted dialysis. After counselling, 54% of the patients who originally declined PD ultimately accepted it. The major reasons for refusing PD were the ideas of "having lived long enough" and "lack of family support." Most other reasons could be overcome by counselling. Only a minority of patients demanded hemodialysis.

CONCLUSIONS

Declining an offer of dialysis was common. Counselling helped patients to accept PD. Certain cultural elements that hindered acceptance of dialysis were involved in the ideas of "having lived long enough" and "lack of family support." Those cultural elements should be tackled more specifically during counselling.

Monitoring disease activity in pemphigus with enzyme-linked immunosorbent assay using recombinant desmogleins 1 and 3

BACKGROUND

Pemphigus is an antidesmoglein (Dsg) autoimmune disease that is divided into two major subtypes: pemphigus foliaceus (PF) and pemphigus vulgaris (PV). We previously developed enzyme-linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 to detect IgG autoantibodies in patients with pemphigus. The protocol for the ELISAs was optimized for serological diagnosis, but under the conditions used, these assays were not particularly useful for monitoring disease activity in certain patients. That is, the sera from some patients with high-titre antibodies continued to show high index values in the ELISA after clinical improvement.

OBJECTIVES

In the study reported here, we modified the ELISA protocol to obtain 'true' index values that exhibit a better correlation with disease activity.

METHODS

We tested two cases of pemphigus foliaceus (PF) and four cases of pemphigus vulgaris (PV), each with ELISA index values greater than 150 for Dsg1 or Dsg3. We ran an ELISA with sera from these patients serially diluted from 1 : 100 to 1 : 12,800. We then performed ELISA with a series of PV No. 1 sera diluted to 1 : 800 and PV No. 2-4 and PF No. 1-2 sera diluted to 1 : 1600, after which we plotted the ELISA index values against the time course of disease activity.

RESULTS

In each of these cases, there was no apparent decline, over the course of the disease activity, in the ELISA index values at a serum dilution of 1 : 100, probably because the antigen-antibody reaction was saturated at that dilution. After running an ELISA with sera serially diluted from 1 : 100 to 1 : 12,800 we found that a linear dose-dependency between the dilution value and the index value was only observed when sera were diluted to 1 : 800 or more in one case (PV No.1) and to 1 : 1600 or more in the other five cases (PV No. 2-4, PF No. 1-2). After performing ELISA with these series as outlined above we plotted the ELISA index values against the time course of disease activity and found that the index values obtained from these appropriately diluted sera fluctuated in parallel with disease activity, and declined with clinical improvement.

CONCLUSIONS

These findings indicate that when appropriate dilutions are used in Dsg1 and Dsg3 ELISA, these assays can provide useful serological information for assessing disease activity in PF and PV.

Hormonal markers and hepatitis B virus-related hepatocellular carcinoma risk: a nested case-control study among men

BACKGROUND

The incidence of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) is higher in men than in women. We examined whether endogenous sex hormone levels or hormone-related factors might affect the risk of HCC in men.

METHODS

Baseline blood samples were collected from 4841 male Taiwanese HBV carriers without diagnosed HCC from 1988 through 1992. Plasma testosterone and estradiol levels and genetic polymorphisms in the hormone-related factors cytochrome P450c17 alpha (CYP17, A1 versus A2 alleles), steroid 5 alpha-reductase type II (SRD5A2, valine [V] versus leucine [L] alleles), and androgen receptor (AR, number of CAG repeats) were assayed among 119 case patients who were diagnosed with HCC during 12 years of follow-up and 238 control subjects. All statistical tests were two-sided.

RESULTS

The risk of HCC increased with increasing concentrations of testosterone (odds ratio [OR](highest versus lowest tertile) = 2.97; 95% confidence interval [CI] = 1.54 to 5.70; P(trend) <.001) and with increasing number of the V allele of the SRD5A2 V89L polymorphism (OR(VV versus LL genotype) = 2.47; 95% CI = 1.21 to 5.03; P(trend) =.011). Fewer AR gene CAG repeats (<23 repeats) were associated with a 1.64-fold (95% CI = 1.00 to 2.68) increased risk of HCC. Although the CYP17 genotype alone did not increase the risk of HCC, there was evidence of a gene-gene interaction, because the CYP17 A1 allele statistically significantly increased the risk of HCC in the presence of fewer AR gene CAG repeats (OR = 2.51; 95% CI = 1.06 to 5.94). We found a similar interaction between the SRD5A2 VV genotype and fewer AR gene CAG repeats (OR = 5.58; 95% CI = 1.86 to 16.71). Body mass index (BMI) modified the association of HCC with testosterone and SRD5A2 genotype; in men with low BMI, multivariate-adjusted ORs for the highest tertile of testosterone versus the lowest and the SRD5A2 VV genotype versus the LL genotype were 7.63 (95% CI = 2.13 to 27.27) and 8.64 (95% CI = 2.75 to 27.14), respectively. No clear associations were found between estradiol or testosterone-to-estradiol ratio and HCC.

CONCLUSIONS

Pathways involving androgen signaling may affect the risk of HBV-related HCC among men.

Current status of aortic aneurysm surgery in Hong Kong

OBJECTIVE

To determine the epidemiology and the status of open and endovascular aortic surgery for aortic aneurysm in Hong Kong.

METHODS

Three separate data sources were obtained: (1) the Hong Kong Hospital Authority discharge statistics for 1999 and 2000; (2) a survey on aortic aneurysms in public hospitals conducted by the working group of vascular surgery; and (3) the department of surgery, University of Hong Kong Medical Center aortic aneurysm database. The disease pattern, distribution as well as audit of operative mortality was determined.

RESULTS

Aortic aneurysm ranked tenth as the leading causes of death in Hong Kong, and the incidence is increasing. Almost 800 new cases were diagnosed each year, with 10% presenting as rupture, but the death rate for ruptured aneurysms was 80%. About half of all operations on aortic aneurysms was performed for rupture, and a significant number of newly diagnosed patients were not receiving surgery. In experienced centers, the operative mortality for elective and ruptured aneurysm have improved to 2% and 38% in recent years. A growing interest and number of endovascular repair operations were performed which has led to some concerns on patient selection and follow up.

CONCLUSIONS

Similar to a worldwide trend, aortic aneurysm in Hong Kong is diagnosed more frequently. With the relatively high mortality for ruptured aneurysms, effective diagnosis and elective surgery on patients with aortic aneurysms in experienced vascular centers remained the best treatment. Since a majority of aneurysms remained untreated, patient and physician education is of paramount importance.

Real-time quantitative PCR analysis for alpha-thalassemia-1 of Southeast Asian type deletion in Taiwan

Since homozygosity of the alpha-thalassemia-1 of Southeast Asian (SEA) type deletion results in hydrops fetalis, a novel protocol based on the real-time quantitating polymerase chain reaction (PCR) technique has been developed to quantify the intact and aberrant alpha-globin genes in adults. The ratio of the normal/SEA-bearing alpha-globin genes was expressed in cycle threshold (C(T)) values. Theoretically, a relative ratio of one to one was anticipated in individuals carrying the SEA type deletion. Twenty-five heterozygous and 20 normal cases were analyzed retrospectively with this protocol. Data showed that the CT values for the intact alpha-globin gene allele and the allele bearing the SEA type deletion in carriers were 28.74+/-1.49 and 26.46+/-2.05, respectively. Therefore, the ratio of normal/SEA type deletion-bearing alpha-globin genes in the carriers was 1.09+/-0.043. No ambiguous results were observed from other less common genotypes associated with alpha-thalassemia, such as the Philippine type deletion. Based on the results, we concluded that this protocol could provide a rapid method to mass screen carriers with alpha-thalassemia-1 of SEA type deletion in this region.

Lipoprotein (a) level and mortality in patients with critical lower limb ischaemia

OBJECTIVE

to investigate if serum lipoprotein (a) level is a predictor of survival in patients with lower limb atherosclerotic occlusive disease.

DESIGN

prospective follow up study.

METHODS

demographic, biochemical and disease variables were collected prospectively in 441 patients with lower limb arterial occlusive disease. Survival data were obtained at a mean follow up of 44 months, and significant risk factors identified by the life table method and multivariate Cox regression analysis.

RESULTS

the cumulative survival for all patients at three and five years was 79% and 63%. Lipoprotein (a) level was the only significant independent biochemical predictor for all deaths and cardiorespiratory deaths on multivariate analysis, along with age, diabetes mellitus, renal impairment, cardiac diseases and major amputation. An elevated Lipoprotein(a) level of >24 mg/dl incurred a 107% and 45% increase in mortality at three and five years respectively. The higher mortality associated with elevated Lipoprotein (a) was particularly evident in patients with critical ischemia, in whom three and five year survival was reduced from 85% to 63% and 67% to 53% (p=0.0064). In claudicants a survival discrepancy was manifested only after five years (73% vs 62%), and the overall association did not reach statistic significance (p=0.52).

CONCLUSIONS

lipoprotein (a) level is a reliable biochemical marker for survival in patients with critical ischemia where traditional atherosclerosis risk factors were prevalent.

Carotid artery aneurysm secondary to cystic medial necrosis

Carotid artery aneurysm secondary to cystic medial necrosis is a rare clinical entity. We report a 59-year-old Chinese male patient who presented with a pulsatile right neck swelling for 2 months. Partial resection of the aneurysm with primary anastomosis of the internal carotid artery was performed. Histopathological examination of the aneurysmal wall demonstrated cystic degeneration of the media with accumulation of glycosaminoglycan material, consistent with the features of cystic medial necrosis. The pathogenesis of carotid artery aneurysm secondary to cystic medial necrosis is discussed.

Long-term prognosis of femoropopliteal bypass: an analysis of 349 consecutive revascularizations

BACKGROUND

Femoropopliteal bypass is the commonest procedure for lower limb revascularization. The aim of the present study was to determine the long-term outcomes of femoropopliteal bypass and evaluate the prognostic significance of various clinical factors on the long-term results.

METHODS

From 1976 to 1998, 349 consecutive primary femoropopliteal bypass operations were performed on 314 patients at the University of Hong Kong Medical Centre. Indications for operation included claudication (n = 85) and limb-threatening ischaemia (n = 264). Univariate and multivariate analyses of 14 clinical variables were undertaken to identify significant prognostic factors affecting the graft patency, limb salvage and patient survival rates.

RESULTS

The overall primary patency rates of femoropopliteal bypass were 88%, 79% and 76% at 1, 3 and 5 years, respectively. Type of graft material and age of patient were independent prognostic factors of graft patency. The cumulative limb salvage rates were 90%, 86% and 86% at 1, 3 and 5 years, respectively. No clinical factor was found to be predictive of ultimate limb loss. The overall survival rates were 89%, 85% and 78% at 1, 3 and 5 years, respectively. Coronary artery disease was the main cause of late death. Gender and indication for operation were the significant predictive factors of long-term survival.

CONCLUSIONS

Femoropopliteal bypass using reversed long saphenous vein provided the most durable long-term patency. Autologous saphenous vein should be the choice of vascular conduit if available. Male gender and limb-threatening ischaemia were associated with a poor survival.

Polymicrobial outbreak of intermittent peritoneal dialysis peritonitis during external wall renovation at a dialysis center

OBJECTIVE

To investigate an outbreak of peritonitis in intermittent peritoneal dialysis (IPD) patients.

DESIGN

An outbreak investigation was performed to identify the etiology of the polymicrobial outbreak, and a retrospective case-control study was conducted to assess the risk factors for development of peritonitis.

SETTING

Renal dialysis center.

PATIENTS

Ten episodes of peritonitis occurred in 8 of 61 patients over a 6-month period in which 669 IPD procedures were analyzed.

INTERVENTIONS

Field visit to renal dialysis center to examine the entire IPD procedure, inspect the hospital environment, and perform air bacterial count.

MAIN OUTCOME MEASURES

The environmental factors and risk factors contributing to the polymicrobial peritonitis outbreak in IPD patients. The incidence of IPD peritonitis was determined before and after interventions.

RESULTS

The causative organisms included Acinetobacter baumanii (6), Stenotrophomonas maltophilia (2), Pseudomonas aeruginosa (1), Candida albicans (1), C. tropicalis (1), Enterococcus (3), and Enterobacteriaceae (2). Four episodes of peritonitis involved infection by more than one organism. Air sampling of the environment detected a median of 110 colony forming units of bacteria per cubic meter of air, 10% of which were found to be Acinetobacter baumanii. The source of this polymicrobial outbreak was attributed to the bamboo scaffolding structure covering the external wall of the hospital during renovation. A retrospective case-control study indicated that the absence of the flush-before-fill step was a risk factor for development of peritonitis.

CONCLUSION

In addition to invasive aspergillosis in transplant or oncology patients, Acinetobacter peritonitis in dialysis patients should be considered another microbial cause of outbreak associated with hospital renovation.

Measuring Lamb wave dispersion curves of a bi-layered plate and its application on material characterization of coating

This paper investigates the Lamb wave dispersion curves of a bi-layered plate and evaluates the feasibility of using the dispersion data to characterize the coating's material properties. The measurement of dispersion curves is based on a focusing PVDF transducer operating in a pulse/echo mode. An image displaying technique is used to determine the dispersion relation of Lamb waves from the measured data. Multiple dispersion curves of Lamb waves are accurately determined over a wide frequency range (4 to 20 MHz). Lamb wave dispersion curves for thin metal sheets electro-deposited with nickel coatings are measured. The elastic constants of the nickel coating are determined by comparing the experimental dispersion data with the theoretical ones calculated numerically. Potential applications of this measurement method are addressed.

Is the preferential use of ePTFE grafts in femorofemoral bypass justified?

The choice of prosthetic graft material for cross-femoral bypass has been evolving in the past two decades. Expanded polytetrafluoroethylene (ePTFE) has become our preferred graft material since 1995. However, few studies have looked into the optimal graft material in this procedure. Justification for the preferential use of ePTFE graft in lower limb revascularization remains unknown. The aim of the present study was to compare the long-term outcomes of Dacron and ePTFE grafts in femorofemoral bypass. The records of 61 consecutive patients who underwent femorofemoral bypass at the University of Hong Kong Medical Center from 1981 to 1998 were retrospectively reviewed. Dacron grafts were used in 27 patients and 34 patients had ePTFE grafts. The demographic features, patency, and limb salvage rates of the two groups of patients were compared. The 3-year primary patency rates of Dacron and ePTFE grafts were 85% (SE = 9.5%) and 66% (SE = 14.5%), respectively. The difference was not statistically significant. The limb salvage rates of Dacron and ePTFE grafts were 91% and 83% at 3 years, respectively (p = 0.27). The long-term outcomes of Dacron and ePTFE grafts in femorofemoral bypass were equivalent. The preferential use of ePTFE graft in femorofemoral bypass is not evidence based. Selection of an appropriate prosthetic graft for femorofemoral bypass should be based on the cost and its handling characteristics.

Endovascular stenting of superficial femoral artery stenosis and occlusions: results and risk factor analysis

PURPOSE

To determine the early and midterm results of femoro-popliteal angioplasty with adjunctive stenting and to identify factors affecting early and continuing success.

METHODS

Sixty-nine consecutive balloon angioplasty procedures on the superficial femoral artery (SFA) were performed in 60 limbs and 55 patients in the operating theater. Fifty-two percent of lesions were occlusions, and 87% involved the distal half or the whole segment of the SFA. Immediate endovascular stenting was used in all procedures, involving the placement of 105 stents, with a mean stented length of 13.8 cm. Twenty-nine procedures (43%) were performed for critical ischemia. Three-monthly duplex ultrasound was used for follow up assessment, with stenosis of > 50% defined as the endpoint for failure. The patient demographic and biochemical data, and procedural details were correlated with success criteria according to Society of Vascular Surgery standards.

RESULTS

Initial technical success by intent to treat was 92%, with four procedure-related complications and no deaths. Initial success by anatomic, hemodynamic and clinical criteria were 98.3, 96.7 and 93.3% respectively (92.2, 90.6 and 87.5% by intent to treat). Cumulative primary patency at 6, 12, and 24 months was 73.1, 62.6 and 53.8%, and secondary patency 84.9, 72.1 and 72.1% correspondingly. Significant factors relating to inferior patency were occlusions, stented segment length > 10 cm, procedure in claudicants, and the use of the Memotherm stent.

CONCLUSIONS

Angioplasty and stenting of the superficial femoral artery has acceptable primary and secondary patency rates even in the presence of long stenosis and occlusions. A duplex surveillance program is recommended for early detection and timely treatment of restenosis.

Changes in venous hemodynamics after superficial vein surgery for mixed superficial and deep venous insufficiency

The purpose of this study was to determine the hemodynamic changes after superficial vein surgery in patients with mixed superficial and deep venous insufficiency (MVI). Between July 1996 and June 1998, all patients with MVI together with saphenofemoral reflux were evaluated prospectively with air plethysmography (APG) and duplex scanning before and 1 month after superficial vein surgery. Saphenofemoral flush ligation without stripping was performed with multiple small incisions for avulsion of varicosities. Seventy-eight patients with 102 operated limbs were included for analysis. The venous filling index (VFI), ejection fraction (EF), and residual volume fraction (RVF) improved significantly after superficial vein surgery (mean VFI 5.99 +/- 3.39 vs. 1.82 +/- 1.21 ml/s, p < 0.001; mean EF 48.39% +/- 11.74% vs. 52.78% +/- 14.33%, p < 0.05; mean RVF 49.80% +/- 11.18% vs. 36.19% +/- 12.98%, p < 0.001, respectively, before and after operation). The proportion of limbs with deep venous incompetence on duplex scanning at more than one site decreased from 70% to 44% after operation. The mean number of sites with deep venous incompetence decreased from 2.14 +/- 0.96 to 1.52 +/- 1.21 after operation (p < 0.001). In conclusion, superficial vein surgery resulted in significant improvement in hemodynamic parameters in limbs with MVI. There was also abolition of deep venous reflux after superficial vein surgery alone. Superficial vein surgery should be the first line of treatment in limbs with MVI, with deep vein reconstructive surgery reserved for those not responding to superficial vein surgery.

Androgen-receptor gene CAG repeats, plasma testosterone levels, and risk of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Worldwide, hepatocellular carcinoma (HCC) is more prevalent in men than in women, suggesting that sex hormones and/or X-chromosome-linked genes may be involved in hepatocarcinogenesis. We investigated the association of a trinucleotide (CAG) repeat in the androgen receptor (AR) gene (located on the X chromosome) termed "AR-CAG repeats," levels of plasma testosterone, and the risk of HCC in Taiwanese men. Chronic hepatitis B virus (HBV) infection, which is associated with risk of HCC, is hyperendemic in Taiwan.

METHODS

We compared the number of AR-CAG repeats in 285 HBV carriers with HCC and in 349 HBV carriers without HCC. We also conducted a nested case--control study on participants in a cohort study. Blood was collected prospectively from 110 case patients and 239 control subjects and was used to determine the number of AR-CAG repeats and plasma testosterone level. All statistical tests were two-sided.

RESULTS

The overall odds ratio (OR) for HCC was 1.72 (95% confidence interval [CI] = 1.03--2.89) for HBV carriers with 20 or fewer AR-CAG repeats compared with those with more than 24 repeats. This association was observed only in patients with late-onset HCC (OR = 2.37; 95% CI = 1.28--4.38). In the nested case-control study, HBV carriers in the highest tertile of testosterone levels had a statistically significantly increased risk of HCC (OR = 2.06; 95% CI = 1.14--3.70) compared with those in the lowest tertile. Elevated testosterone was more strongly associated with early-onset (OR = 4.67; 95% CI = 1.41--15.38) than late-onset disease. HBV carriers with 20 or fewer AR-CAG repeats and higher testosterone levels had a fourfold increase in HCC risk compared with those with more than 24 repeats and testosterone levels in the lowest tertile.

CONCLUSIONS

Higher levels of androgen signaling, reflected by higher testosterone levels and 20 or fewer AR-CAG repeats, may be associated with an increased risk of HBV-related HCC in men.

Non-radioactive Southern hybridization for early diagnosis of alpha-thalassemia with southeast Asian-type deletion in Taiwan

Alpha-thalassemia has been estimated to account for over 60% of hydrops fetalis cases in Taiwan. The most common genotypic lesion found in alpha-thalassemia-1 cases in Taiwan is deletion of a large segment of the alpha-globin gene cluster, termed the Southeast Asian-type deletion (-SEA/; further referred to as SEA-type deletion). Seven chorionic villus samples (CVS) from pregnancies of couples both heterozygous for SEA-type deletion were studied. Non-radioactive Southern-blot hybridization using the dig-alkaline phosphatase detection system was developed to fulfill this purpose. The results were compared with corresponding polymerase chain reaction (PCR) data to elucidate the effectiveness of these two protocols in the diagnosis of the SEA-type deletion. The data showed that of the seven CVS, three demonstrated a distinctive band pattern, indicating their homozygous status of SEA-type deletion, whereas two showed heterozygous patterns, and the other two were free of the deletion. Homozygosity of the deletion was confirmed by Southern-blot hybridization performed on DNA samples extracted from the abortus tissue. However, two of the three cases with SEA-type deletion showed heterozygous PCR results. Maternal cell contamination could be responsible for the artifacts in the PCR results, but the influence due to the contamination is minimal in non-radioactive Southern-blot hybridization. We concluded that PCR is suitable for screening of carrier adults with SEA-type deletion, and non-radioactive Southern hybridization is ideal for early prenatal diagnosis of the SEA-type deletion.

DNA polymorphism of Mycobacterium abscessus analyzed by infrequent-restriction-site polymerase chain reaction

BACKGROUND

Mycobacterium abscessus is an important pathogen that has been increasingly associated with many clinical and nosocomial infections. A reliable molecular typing scheme is essential for the epidemiological study of this rapidly growing mycobacterium. Pulsed-field gel electrophoresis (PFGE), considered to be the gold standard among molecular typing methods, has failed to provide satisfactory results in the molecular typing of this bacterium. A newly developed molecular typing method, infrequent-restriction-site polymerase chain reaction (IRS-PCR), was examined in this study to determine its suitability for fingerprinting M. abscessus isolates.

METHODS

Eight clinical isolates of M. abscessus and two reference strains (M. abscessus ATCC 19977 and M. chelonae ATCC 35749) were studied by DNA macrorestriction analysis with XbaI resolved by PFGE, and IRS-PCR assay with adaptors designed for XbaI and HhaI restriction sites.

RESULTS

By PFGE, different banding patterns were found in two clinical isolates of M. abscessus; the other isolates yielded only broken DNA and could not be assessed. By IRS-PCR, unique patterns were noted for the 10 isolates; the 10 appeared to be genetically different.

CONCLUSION

IRS-PCR may be an efficient substitute for PFGE in analyzing the DNA polymorphism and epidemiology of M. abscessus.

Long-term outcome of aortofemoral bypass for aortoiliac occlusive disease

INTRODUCTION

Revascularisation of aortoiliac occlusive disease has been evolving in the past 2 decades. The present study was undertaken to evaluate the long-term outcomes of aortofemoral bypass for aortoiliac occlusive disease at a tertiary vascular disease centre in Hong Kong.

MATERIALS AND METHODS

A retrospective analysis of 94 patients (176 limbs) who survived aortofemoral bypass was performed to evaluate the graft patency, long-term complications, limb loss and patient survival rates. Thirty-six patients were operated for incapacitating claudication (Group I) and 58 for limb salvage (Group II).

RESULTS

The overall primary patency rates of aortofemoral bypass were 97%, 90%, 89% and 84% at 1, 3, 5 and 10 years, respectively. Poor distal run-off and neointimal hyperplasia were the leading causes of late graft failure. Other late complications included femoral pseudoaneurysm (n = 1), infection (n = 1) and femoral graft aneurysms (n = 2). The limb loss rate was 5.1% at 4 years. The overall survival rates were 95%, 86%, 81% and 75% at 1, 3, 5 and 10 years, respectively. Ischaemic heart disease and malignancy were the 2 major causes of late death. The 5-year survival rate of group I patients (96%) was significantly superior to that of group II patients (70%).

CONCLUSIONS

Aortofemoral bypass achieved a primary patency rate of 89% at 5 years and a satisfactory limb salvage rate. It remains the preferred treatment option for good risk patients with complete occlusion or extensive stenosis of the aortoiliac arteries.