Re-revision of failed revision Total Hip Arthroplasty acetabular components.

While revision of total hip arthroplasty (THA) is being performed with increasing frequency, outcomes of repeated revisions have been rarely reported in the literature. The purpose of this study was to report mid-term outcomes of re-revision of failed revision THA acetabular components. We performed at least two revisions of the failed acetabular component in 57 patients (57 hips) between August 1996 and April 2008. Of these, 15 patients with infection were excluded and one died before 4-year evaluation. The final study cohort consisted of 41 patients (41 hips) with a mean age of 55.5 years (range, 37 to 82). Preoperative acetabular bone defects was classified as Paprosky Type IIA in 4 hips, Type IIB in 6, Type IIC in 9, Type IIIA in 16, and Type IIIB in 6. The mean duration of follow-up was 7.2 years (range, 4 to 15). Mean Harris hip score improved 45 points preoperatively to 83 points postoperatively. Six hips (14.6%) required additional revision procedure: 3 for aseptic loosening, 2 for deep infection, and 1 for recurrent instability. Complications included 2 dislocations and 1 peroneal nerve palsy. Kaplan-Meier survivorship with an end point of reoperation for any reason was 88.5% (95% CI, 78.0% to 100%) at 7.2 years. For aseptic loosening of the acetabular component, the survival was 91.8% (95% CI, 80.8% to 100%) at 7.2 years. Rerevision with contemporary uncemented cup or antiprotrusio cage for failed revision THA acetabular components showed encouraging mid-term outcomes for this technically challenging condition.

Inhibition of choline kinase as an antiamoebic approach in Entamoeba histolytica infection.

Entamoeba histolytica is the parasite responsible for amoebiasis, which can result in amoebic colitis or amoebic liver abscess. Metronidazole has been the conventional treatment for intestinal amoebiasis, but concerns regarding resistance have emerged due to the identification of resistance pathways in E. histolytica. This study investigates a novel anti-amoebic approach targeting the CDP-choline pathway. Inhibition studies were conducted using potential choline kinase (CK) inhibitors to inhibit the EhCK enzyme, and RNA interference was employed to knock down the EhCK gene. Km and Vmax of purified EhCK and hCKa2 proteins were determined by pyruvate kinase-lactate dehydrogenase (PK-LDH) coupled assay. The IC50 values for EhCK and hCKa2 were determined with several commercial CK inhibitors. Selected inhibitors were incubated with E. histolytica trophozoites for 48 hours to determine the EC50 for each inhibitor. Silencing of gene encoding EhCK was carried out using duplex siRNA and the gene expression level was measured by real-time qPCR. Based on the IC50 values, three of the inhibitors, namely CK37, flavopiridol and H-89 were more potent against EhCK than hCKa2. Trophozoites growth inhibition showed that only HDTAB, H-89 and control drug metronidazole could penetrate and induce cell death after 48-hour incubation. siRNA concentration of 10 µg/mL was used for the transfection of positive control GAPDH, EhCK, and non-targeting GFP siRNAs. RNAi experiment concluded with positive control GAPDH downregulated by 99% while the level of EhCK mRNA was downregulated by 47%. In this study, potential inhibitors of EhCK and siRNA have been identified, paving the way for further refinement and testing to enhance their potency against EhCK while sparing hCK. The utilization of these specific inhibitors and siRNA targeting EhCK represents a novel approach to impede the growth of E. histolytica by disrupting its phospholipid synthesis pathway.

New extensometer to measure in vivo uniaxial mechanical properties of human skin.

Biomechanical properties of skin are important for clinical decision making as well as clinical intervention. Measuring these properties in vivo is critical for estimating dimensional behaviour of skin flap or graft after harvest. However, existing methodologies and devices often suffer from lack of standardisation and unwanted peripheral force contribution due to the deformation of surrounding tissues during measurement. This naturally leads to measurement inaccuracies and lack of reproducibility. In order to improve the measurement accuracy, a new portable extensometer, which measures the non-invasive in vivo biomechanical properties of skin, has been designed and constructed. This design incorporates three pads that attach to the skin, including a C-shaped pad to shield the force sensor from peripheral forces. Such design produces data that are significantly closer to in vitro measurements. The results have been verified by finite element analysis, and experiments on rubber sheets and pig skins. This device can be used to obtain biomechanical properties of skin that will aid doctors in measuring skin elasticity and surgical planning, especially in skin flap surgery.

Non-invasive prediction of skin flap shrinkage: a new concept based on animal experimental evidence.

A non-invasive, in vivo method has been developed to predict the skin flap shrinkage (retraction) following a harvest. It involves the use of a novel custom-designed extensometer to measure the force-displacement behaviour of skin and subsequent data analysis to estimate the shrinkage. In validation experiments performed on pigs, this method has been shown to produce results with an average absolute error of 6.0% between the actual and predicted shrinkages. This may be close to what an experienced surgeon would estimate subjectively, thus indicating the potential usefulness of this method to predict flap shrinkage of patient's donor sites.

A hypothetical oxidative stress regulatory role of alpha giardins in the protozoan parasite Giardia intestinalis.

Giardiasis is an intestinal infection caused by the protozoan parasite Giardia intestinalis, affecting hundreds of millions of people worldwide. This microaerophilic protozoan is capable of surviving in the host intestine in the presence of both oxygen and reactive oxygen species (ROS), despite the lack of conventional ROS-scavenging enzymes. The understanding of how G. intestinalis tolerates free radicals could help to identify essential biological processes that protect themselves against oxidative stress within the human gut. This review outlines the antioxidant mechanisms that are utilized by G. intestinalis, with an emphasis on the potential novel role of alpha giardins. The comprehensive understanding of the processes involved in oxidative stress management may provide new insights into improved treatments for giardiasis, and other medically important protozoan parasitic diseases.

Numerical analysis of flow distribution behavior in a proton exchange membrane fuel cell.

The flow distribution of a proton exchange membrane fuel cell within a manifold plays an important role on its performance. This study presents a numerical analysis of the flow distribution behavior within different manifold configurations. A two-dimensional model with 75 cells was employed to study the flow behavior. The variation in the stoichiometry and number of cells was also studied. Three different flow configurations were considered with different numbers of flow inlets and outlets. The flow characteristics, such as the pressure and velocity variations in the manifold and cells, were measured to determine the effects of the different flow configurations. The results indicated that the double inlet/outlet configuration had the best flow distribution when using 75 cells. Moreover, increasing the stoichiometry resulted in a better flow distribution to the cells in a stack.

Prevalence and Distribution of Anti-Amoebic IgG Antibody among Orang Asli (Aborigines) in Peninsular Malaysia.

Entamoeba species are commonly detected in stool samples of Orang Asli due to their substandard living conditions and poor hygiene. Among the Entamoeba spp., Entamoeba histolytica is the only known primary pathogenic species. This study determined the prevalence and distribution of anti-amoebic IgG antibody among Orang Asli in Peninsular Malaysia. The results would reflect the prevalence of amoebiasis in the population. This study analysed a total of 375 serum samples from archives of two Orang Asli projects conducted between 2011 and 2014. They were from six different states in Malaysia, namely Johor, Kedah, Kelantan, Pahang, Perak, and Selangor. Anti-amoebic IgG antibody was detected using an enzymelinked immunosorbent assay (ELISA) with crude soluble antigen produced from axenically grown E. histolytica trophozoites. From the analysis, the overall seropositivity was approximately 71% (266/375), while the seropositivity rates for each of the three Orang Asli tribes i.e. Senoi, Negrito and Proto-Malay, were 66% (137/208), 92% (103/112), and 43% (17/ 41) respectively. Orang Asli from Kedah [95% (52/55)] showed the highest seropositivity, followed by Kelantan [79% (54/68)], Perak [73% (78/107)], Pahang [60% (57/95)], Selangor [56% (14/25)], and Johor [48% (10/21)]. Orang Asli from rural [76% (192/254)] and peripheral urban [65% (69/106)] areas showed significantly higher seropositivity (p=0.002) than those from urban areas [36% (4/11)]. The high prevalences of anti-amoebic IgG antibody in these Orang Asli populations comprised both active and past infections. This study provides current insights of amoebiasis in selected Orang Asli settlements in Peninsular Malaysia. The high seropositivity of anti-amoebic IgG antibody suggests that the settlements are endemic for amoebiasis and there is a high risk of acquiring E. histolytica infection among the dwellers.

Various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke.

BACKGROUND AND PURPOSE: Various clinical subtypes of patients presenting with sudden-onset ischemic stroke have been recognized, but classification of those types is not simple. We identified various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke with relation to clinical outcomes. METHODS: Twelve patients with symptoms of acute ischemic stroke due to middle cerebral artery occlusion underwent perfusion-weighted MR imaging and MR angiography within 6 hours after the onset of symptoms. Perfusion-weighted imaging was performed with a conventional dynamic contrast-enhanced T2*-weighted sequence, and cerebral blood volume (CBV) maps were then created. CBV maps and MR angiographic findings were compared with 99mTc-HMPAO brain SPECT scans, short-term outcomes, and follow-up imaging findings. RESULTS: The combined CBV and MR angiographic findings were classified into three patterns: arterial occlusion and decreased CBV (n = 8), arterial occlusion and increased CBV (n = 2), and no arterial occlusion and normal CBV (n = 2). These three patterns were strongly related to SPECT findings, short-term outcomes, and follow-up imaging findings. Perfusion on SPECT decreased markedly in the affected regions in all patients with the first pattern, decreased slightly in the second pattern, and was normal in the third pattern. Symptoms were not significantly changed at 24 hours after onset in any of the patients with the first pattern, but resolved completely in all patients with the latter two patterns. Follow-up imaging showed large infarctions in all patients with the first pattern. Initially, no infarction was seen in the second pattern, but watershed infarction developed later in one of these patients. CONCLUSION: Hyperacute ischemic stroke may be differentiated into three imaging patterns with different clinical outcomes. The combined use of perfusion-weighted MR imaging and MR angiography may play a substantial role in guiding the choice of treatment of this disease.

Correlative assessment of hemodynamic parameters obtained with T2*-weighted perfusion MR imaging and SPECT in symptomatic carotid artery occlusion.

BACKGROUND AND PURPOSE: Perfusion MR imaging and single-photon emission CT (SPECT) are commonly used to evaluate hemodynamic status in patients with symptomatic occlusive cerebrovascular disease. These techniques rely on different underlying physiological mechanisms, and the data may not correspond. We studied the relationship between hemodynamic parameters obtained with these two methods. METHODS: We performed perfusion MR imaging and SPECT in 10 patients with symptomatic unilateral internal carotid artery occlusion. Relative cerebral blood volume (rCBV) and uncorrected mean transit time (uMTT) were obtained with dynamic contrast-enhanced T2*-weighted MR imaging. Relative cerebral blood flow (rCBF) and vascular reserve capacity were measured with 99mTc-HMPAO SPECT; vascular reserve capacity was calculated by the difference in CBF before and after acetazolamide challenge. Ratios of these hemodynamic parameters between the affected and contralateral vascular territories were calculated and compared. RESULTS: Normal-to-increased CBV, prolonged uMTT, decreased CBF, and normal-to-diminished vascular reserve capacity were observed in the affected vascular territories. Reduction of vascular reserve capacity corresponded well with uMTT but not with CBF and CBV. CBF, CBV, and uMTT did not correspond to one another. CONCLUSION: uMTT is more sensitive than the other parameters in estimating vascular reserve capacity. The relationship between parameters obtained with perfusion MR imaging and SPECT should be considered in assessing the hemodynamic status of patients with symptomatic occlusive cerebrovascular disease.

A recombinant antigen-based IgG4 ELISA for the specific and sensitive detection of Brugia malayi infection.

An IgG4 ELISA based on a novel recombinant antigen was evaluated for detection of Brugia malayi infection, using 2487 sera from various institutions: 2031 samples from Universiti Sains Malaysia, 276 blinded sera from 2 other institutions in Malaysia, 140 blinded sera from India and 40 blinded sera from Thailand. These sera were from various groups of individuals, i.e., microfilaraemics, chronic patients, endemic normals, non-endemic normals and individuals with other parasitic and bacterial infections. Based on a cut-off optical density reading of 0.300, the IgG4 ELISA demonstrated specificity rates of 95.6-100%, sensitivity rates of 96-100%, positive predictive values of 75-100% and negative predictive values of 98.9-100%. These evaluation studies demonstrated the high specificity and sensitivity of this test for the detection of active B. malayi infection. Thus, the IgG4 ELISA would be very useful as a tool in diagnosis and in elimination programmes for brugian filariasis.

Specificity and sensitivity of a rapid dipstick test (Brugia Rapid) in the detection of Brugia malayi infection.

A total of 753 serum samples from 6 institutions in 3 countries (Malaysia, Indonesia and India) were used to evaluate an immunochromatographic rapid dipstick test, Brugia Rapid, for diagnosis of Brugia malayi infection. The samples comprised sera from 207 microfilaria-positive individuals and 546 individuals from filaria non-endemic areas. The latter consisted of 70 individuals with soil-transmitted helminth infections, 68 with other helminth infections, 238 with protozoan infections, 12 with bacterial and viral infections and 158 healthy individuals. The dipstick is prepared with a goat anti-mouse antibody control line and a B. malayi recombinant-antigen test line. First, the dipstick is dipped into a well containing diluted patient serum, thus allowing specific anti-filarial antibody in the serum to react with the recombinant antigen. Then the dipstick is placed into an adjacent well containing reconstituted anti-human IgG4-gold. After 10 min, development of 2 red-purplish lines denotes a positive result and one line indicates a negative reaction. The overall results of the evaluation showed 97% sensitivity, 99% specificity, 97% positive predictive value and 99% negative predictive value. Brugia Rapid is thus a promising diagnostic tool for detection of B. malayi infection, and would be especially useful for the brugian filariasis elimination programme.

Endoscopic management of submandibular sialolithiasis.

BACKGROUND: Transoral removal and sialoadenectomy are the two main modalities of treatment for submandibular stones. However, missed ductal stones are not uncommon, and there is a risk of lingual or hypoglossal nerve injury. We attempted to avoid these complications by using an endoscopic technique. METHODS: The case notes of the patients who had undergone endoscopic removal of submandibular stones were studied retrospectively. The procedure was performed under general anesthesia. The submandibular orifice was incised by carbon dioxide laser, and a 3.1-mm rigid scope was inserted under direct vision with normal saline irrigation after dilatation. The stones were either broken down by laser or removed with a Dormia basket or forceps. RESULTS: A total of 13 patients underwent the procedure. The duration of median follow-up was 15 months. In 11 patients, the stones were identified and removed. No stone was found in two patients (15.4%). There were no false negatives, since no stones were discovered subsequently in these two patients. One, two, three, and four stones were present inside the ducts in seven patients (54.6%), one patient (7.7%), two patients (15.4%), and one patient (7.7%), respectively. The symptoms subsided completely in 11 patients within 4 weeks after the procedure. Persistent swelling occurred in two patients. In one of them, no residual stone was revealed by CT scan. The other patient had a large calculus that was only partially fragmented by laser lithotripsy at the initial operation. No lingual nerve or hypoglossal nerve injury was detected in any patient. CONCLUSION: Sialoendoscopy is a safe and efficacious treatment for submandibular ductal stones. It reduces the incidence of missed stones, and nerve injury, as well as the need for sialoadenectomy.

Case report: perinephric angiomyolipomas in tuberous sclerosis.

Bilateral large perinephric angiomyolipomas in a young Chinese woman with tuberous sclerosis are reported. Computed tomography (CT) demonstrated large fatty masses, containing abnormally dilated blood vessels and muscle strands, within the Gerota's fascia bilaterally. There were multiple foci of involvement in both kidneys. The diagnosis was confirmed on histological examination of the excised left perinephric angiomyolipoma and nephrectomy specimens. The patient subsequently developed bilateral pneumothoraces which were surgically treated. High resolution CT showed extensive thin-walled cysts in both lungs.

Post-mastectomy radiotherapy after immediate autologous breast reconstruction in primary treatment of breast cancers.

AIM: To assess the clinical outcome of breast cancer patients with immediate autologous breast reconstruction and post-mastectomy radiotherapy (PMRT) as primary treatment. MATERIALS AND METHODS: Twenty-five women with breast cancer treated with immediate autologous breast reconstruction and post-mastectomy radiotherapy as primary treatment between 1995 and 2001 in Pamela Youde Nethersole Eastern Hospital of Hong Kong were retrospectively studied. Radiation doses of 50 Gy (in 2 Gy daily fraction) were given to the reconstructed breasts, except one who was given 45 Gy (in 1.8 Gy daily fraction). Nine women (36%) were treated without bolus, whereas the other 16 women (64%) were treated with 0.5 cm thick bolus on alternate days. The main outcome measures include local control, treatment complications and cosmetic outcome. RESULTS: Median follow-up was 3.7 years (range: 1.0-6.6 years). Two women (8%), who were treated without bolus, developed chest wall recurrences. The overall 5-year, actuarial, local failure-free rate and disease-specific survival rate were 89.8% and 77.9%, respectively. Apart from mild acute skin reactions, no significant acute radiotherapy side-effects were observed. No flap necrosis or flap loss was seen. The cosmesis of the reconstructed breasts were rated as good to excellent in 85% of the surviving patients. There was no observed adverse effect on cosmesis by adding bolus on alternate days. CONCLUSION: PMRT after immediate autologous tissue-flap breast reconstruction is well tolerated and is not associated with increased incidence of complications. Adding 0.5 cm bolus on alternate days might improve local control without causing adverse cosmetic effect. The concern of adverse effects of radiotherapy should not exclude the choice of immediate breast reconstruction in suitable patients.

Ruptured subcapsular haematoma of the liver in pregnancy; a case report.

A case of ruptured subcapsular haematoma of the liver, a rare and potentially lethal complication of pre-eclampsia, is presented. The lack of characteristic signs and symptoms is highlighted. This case serves to remind clinicians of the high maternal and perinatal mortality rates associated with complications of hypertension in pregnancy.

Free vascularized transfer of the metatarsophalangeal and proximal interphalangeal joints of the second toe for reconstruction of the metacarpophalangeal joints of the thumb and index finger using a single vascular pedicle.

Previously described double-joint transfers from a single toe have required a separate vascular pedicle for each joint transferred. In this case report, however, we describe the use of a single vascular pedicle to perform a free vascularized double-joint transfer of the metatarsophalangeal and proximal interphalangeal joints of a single toe to the metacarpophalangeal joints of the thumb and index finger. Although a pollicization could have restored adequate function to the patient's hand, she desired five digits. Given the increased distance between the metacarpophalangeal joints of the thumb and index finger, an increased interjoint pedicle length was needed. We obtained this by mobilizing the digital vessels away from the joints of the second toe. This involved transecting the tibial digital vascular branches of the proximal interphalangeal joint and the fibular vascular branches of the metatarsophalangeal joint. Based on a single pedicle, the vascularity of the proximal interphalangeal joint was maintained by preserving the distal commissural vessels at the distal phalanx. Advantages of this technique include using a single donor artery and reconstruction of two metacarpal joints with a single toe.

The lateral forearm flap as a modification of the lateral arm flap: vascular anatomy and clinical implications.

The forearm extension of the lateral arm flap was introduced on the basis of the vascular territory of the posterior radial collateral artery extending beyond the elbow into the forearm. However, there is controversy as to whether the posterior radial collateral artery extends as a single trunk below the elbow or if it terminates more proximally with only a rich vascular plexus extending beyond the elbow. The purpose of this study was to revisit the artery's anatomy in the region of the elbow and to study its distribution in the forearm. Using latex and barium-gelatin injections of the posterior radial collateral artery in ten cadaveric upper limbs, it was observed that terminal branching of the artery occurred 4.5 cm proximal to the lateral epicondyle of the humerus. Distal to the epicondyle, the terminal branches of the posterior radial collateral artery were seen to fan out as finely arborized branches supplying the lateral forearm skin. No single, constant vascular trunk to the forearm skin could be identified. Furthermore, in its distribution toward the periphery, the terminal branches of the posterior radial collateral artery took an increasingly superficial course. Proximal to the epicondyle, the vessels lay deep within the subcutaneous fat, whereas distal to the epicondyle, they were very close to skin. These findings suggest that lateral forearm skin cannot be islanded without risk of vascular disruption and that the distally sited flap should include skin proximal to the epicondyle for safety.

A modification of the technique for intravenous regional blockade for hand surgery.

A prospective study was conducted to assess a modification to Bier's intravenous regional anaesthesia which introduced a third temporary distal forearm tourniquet. This confines the injected lignocaine to the hand, resulting in a higher local lignocaine concentration. Subsequent exsanguination of the limb then channels the remaining intravascular lignocaine under the distal cuff of a double tourniquet. Of the 18 patients, none experienced pain during operation and all tolerated the tourniquet without significant discomfort. Mild postoperative giddiness was noted in one patient. No other anaesthetic complications were encountered. In a subjective assessment of the bloodlessness of the operating field, two were ranked satisfactory, ten good and six excellent. None of the patients required re-exsanguination when using this technique.

Outcomes and complications of thyroid surgery: retrospective study.

OBJECTIVE: To study the outcome and complications of thyroid surgery. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Three hundred and twelve patients (266 women and 46 men) underwent thyroid surgery between January 1994 and December 1999. MAIN OUTCOME MEASURES: Complications of thyroidectomy for various thyroid diseases according to surgical technique used. RESULTS: Capsular dissection gradually became a more popular surgical technique: 33% and 58% in the first and second halves of the study period respectively (P<0.001). The overall rate of permanent vocal cord palsy was 2%. Near-total thyroidectomy became the preferred surgical treatment for toxic goitre over the study period. The incidence of recurrent hyperthyroidism was reduced from 21% to 7% (P>0.1, not significant). The incidence of hypoparathyroidism was approximately 30% after thyroidectomy for cancer. CONCLUSION: Capsular dissection is increasingly utilised in thyroid surgery. Low complication rates can be achieved after thyroidectomy for benign diseases. Hypoparathyroidism, however, is a relatively common complication after surgery for thyroid cancer.

Breast conservation treatment in Hong Kong-early results of 203 patients: retrospective study.

OBJECTIVE: To study the clinical outcomes of patients with invasive or non-invasive breast cancer after breast conservation treatment. DESIGN: Retrospective study. SETTING: Clinical oncology department of a public hospital, Hong Kong. PATIENTS: Two hundred and three patients who received postlumpectomy radiotherapy at the Pamela Youde Nethersole Eastern Hospital between January 1994 and June 1999. INTERVENTIONS: Adjuvant radiotherapy with or without systemic adjuvant treatment. MAIN OUTCOME MEASURES: Actuarial local control rate, progression-free survival rate, disease-specific survival rate, and cosmetic score. RESULTS: The median follow-up was 3.5 years. Two of the 25 patients with carcinoma in situ only developed local recurrence; the 5-year actuarial local control rate was 91.3%. Among the 178 patients with invasive cancer, seven had a local recurrence and 12 developed distant metastases without local failure. The 5-year actuarial local control, progression-free survival, and disease-specific survival rates for patients with invasive cancer were 95.5%, 85.8%, and 95.2%, respectively. The risk of local recurrence was significantly increased for younger patients (age <40 years) and those with positive final margins. Cosmetic scores were rated good to excellent by 95.6% of patients. CONCLUSIONS: The early clinical outcomes of these patients are comparable to those in large overseas trials, which have demonstrated the equivalence of mastectomy and breast conservation treatment in terms of survival. In addition to mastectomy, with or without breast reconstruction, breast conservation treatment should be offered as an alternative to suitable Chinese women. To maximise local control, further excision or mastectomy is recommended for patients with positive final margins.