MyMedR

Displaying publications 161 - 180 of 250 in total

Abstract:

Sort:

Fulltext Computed tomography of blunt renal trauma

Razali MR, Azian AA, Amran AR, Azlin S

Singapore Med J, 2010 Jun;51(6):468-73; quiz 474.
PMID: 20658105

Renal injury is observed in 10 percent of cases of abdominal trauma, and the majority (80 percent to 90 percent) of these are attributable to blunt trauma. Intravenous urography and ultrasonography of the abdomen were previously the modalities of choice in the imaging of renal injuries. However, computed tomography (CT) is currently the imaging modality of choice in the evaluation of blunt renal injury, since it provides the exact staging of renal injuries. The purpose of this article is to describe the CT staging of renal injuries observed in blunt abdominal trauma based on the Federle Classification and the American Association for the Surgery of Trauma renal injury severity scale.

Matched MeSH terms: Kidney/blood supply
Fulltext Morphometric analysis of skin microvasculature in the diabetic foot

Yusof MI, Al-Astani AD, Jaafar H, Rashid FA

Singapore Med J, 2008 Feb;49(2):100-4.
PMID: 18301834

INTRODUCTION: This study was designed to evaluate the histopathological features of skin microvasculature in patients with a diabetic foot, specifically the number of blood vessels, number of endothelial cells and endothelial thickness.
METHODS: This study involved 41 diabetic foot patients admitted to Hospital Universiti Sains Malaysia for surgical management of foot problems. Skin biopsies were taken for histological evaluation following surgical procedures, such as wound debridement or local foot amputation. The skin microvasculature features examined were the number of blood vessels, the endothelial thickness of the vessels and the cross-sectional endothelial cell count. The findings were compared with the similar parameters of non-diabetic patients (control) and analysed.
RESULTS: The mean blood vessel count (BVC), endothelial cell thickness (ECT) and endothelial cell count (ECC) for the diabetic group were 12.56 +/- 2.77, 4.81 +/- 1.5 micrometres and 7.07 +/- 1.88, respectively. The mean BVC, ECT and ECC for the non-diabetic control group were 5.25 +/- 1.98, 1.9 +/- 0.55 micrometres and 4.11 +/- 1.17, respectively. The mean BVC, ECT and ECC for the diabetic group were significantly higher than those for the non-diabetic control group.
CONCLUSION: The increased number of blood vessels to the skin and their endothelial cell number and thickness may be the contributing factors for problems related to the diabetic foot, such as tendency for skin ulceration, infection and poor wound-healing in these patients. These may also contribute to secondary changes of diabetic foot lesions, indicating failure of adequate vascularisation of the foot.

Matched MeSH terms: Skin/blood supply
Deep-vein thrombosis rates after major orthopedic surgery in Asia. An epidemiological study based on postoperative screening with centrally adjudicated bilateral venography

Piovella F, Wang CJ, Lu H, Lee K, Lee LH, Lee WC, et al.

J Thromb Haemost, 2005 Dec;3(12):2664-70.
PMID: 16359505

BACKGROUND: The incidence of postsurgical venous thromboembolism is thought to be low in Asian ethnic populations.
OBJECTIVE: We studied the incidence of deep-vein thrombosis (DVT) in Asian patients undergoing major orthopedic surgery of the lower limbs.
PATIENTS/METHODS: We performed a prospective epidemiological study in 19 centers across Asia (China, Indonesia, South Korea, Malaysia, Philippines, Taiwan, and Thailand) in patients undergoing elective total hip replacement (THR), total knee replacement (TKR) or hip fracture surgery (HFS) without pharmacological thromboprophylaxis. The primary endpoint was the rate of DVT of the lower limbs documented objectively with bilateral ascending venography performed 6-10 days after surgery using a standardized technique and evaluated by a central adjudication committee unaware of local interpretation.
RESULTS: Overall, of 837 Asian patients screened for this survey, 407 (48.6%, aged 20-99 years) undergoing THR (n = 175), TKR (n = 136) or HFS (n = 96) were recruited in 19 centers. DVT was diagnosed in 121 of 295 evaluable patients [41.0%, (95% confidence interval (CI): 35.4-46.7)]. Proximal DVT was found in 30 patients [10.2% (7.0-14.2)]. Total DVT and proximal DVT rates were highest in TKR patients (58.1% and 17.1%, respectively), followed by HFS patients (42.0% and 7.2%, respectively), then THR patients (25.6% and 5.8%, respectively). DVT was more frequent in female patients aged at least 65 years. Pulmonary embolism was clinically suspected in 10 of 407 patients (2.5%) and objectively confirmed in two (0.5%).
CONCLUSIONS: The rate of venographic thrombosis in the absence of thromboprophylaxis after major joint surgery in Asian patients is similar to that previously reported in patients in Western countries.

Matched MeSH terms: Lower Extremity/blood supply
Fulltext Persistent Brainstem Dysfunction in Long-COVID: A Hypothesis

Yong SJ

ACS Chem Neurosci, 2021 Feb 17;12(4):573-580.
PMID: 33538586 DOI: 10.1021/acschemneuro.0c00793

Long-COVID is a postviral illness that can affect survivors of COVID-19, regardless of initial disease severity or age. Symptoms of long-COVID include fatigue, dyspnea, gastrointestinal and cardiac problems, cognitive impairments, myalgia, and others. While the possible causes of long-COVID include long-term tissue damage, viral persistence, and chronic inflammation, the review proposes, perhaps for the first time, that persistent brainstem dysfunction may also be involved. This hypothesis can be split into two parts. The first is the brainstem tropism and damage in COVID-19. As the brainstem has a relatively high expression of ACE2 receptor compared with other brain regions, SARS-CoV-2 may exhibit tropism therein. Evidence also exists that neuropilin-1, a co-receptor of SARS-CoV-2, may be expressed in the brainstem. Indeed, autopsy studies have found SARS-CoV-2 RNA and proteins in the brainstem. The brainstem is also highly prone to damage from pathological immune or vascular activation, which has also been observed in autopsy of COVID-19 cases. The second part concerns functions of the brainstem that overlap with symptoms of long-COVID. The brainstem contains numerous distinct nuclei and subparts that regulate the respiratory, cardiovascular, gastrointestinal, and neurological processes, which can be linked to long-COVID. As neurons do not readily regenerate, brainstem dysfunction may be long-lasting and, thus, is long-COVID. Indeed, brainstem dysfunction has been implicated in other similar disorders, such as chronic pain and migraine and myalgic encephalomyelitis or chronic fatigue syndrome.

Matched MeSH terms: Brain Stem/blood supply
Fulltext Influence of combined hypertension and renal failure on functional alpha(1)-adrenoceptor subtypes in the rat kidney

Hye Khan MA, Sattar MA, Abdullah NA, Johns EJ

Br J Pharmacol, 2008 Mar;153(6):1232-41.
PMID: 18246093 DOI: 10.1038/bjp.2008.13

This study investigated whether the alpha(1)-adrenoceptor responsiveness of the renal vasculature was altered in the state of hypertension combined with renal failure.

Matched MeSH terms: Kidney/blood supply
MicroRNAs associated with tumour migration, invasion and angiogenic properties in A549 and SK-Lu1 human lung adenocarcinoma cells

Ho CS, Yap SH, Phuah NH, In LL, Hasima N

Lung Cancer, 2014 Feb;83(2):154-62.
PMID: 24360396 DOI: 10.1016/j.lungcan.2013.11.024

Dysregulation in miRNA expression contributes towards the initiation and progression of metastasis by regulating multiple target genes. In this study, variations in miRNA expression profiles were investigated between high and low invasive NSCLC cell lines followed by identification of miRNAs with targets governing NSCLC's metastatic potential.

Matched MeSH terms: Adenocarcinoma/blood supply; Lung Neoplasms/blood supply
Fulltext Challenges in the management of massive intraorbital and hemifacial arteriovenous malformation as causing life-threatening epistaxis

Manuel AM, Kalimuthu S, Pathmanathan SS, Narayanan P, Zainal Abidin Z, Azmi K, et al.

Asian J Surg, 2017 Apr;40(2):158-162.
PMID: 24210537 DOI: 10.1016/j.asjsur.2013.09.011

Arteriovenous malformations are congenital lesions that may evolve with time and manifest in a plethora of presentations. They can occur as torrential epistaxis when it extensively involves the facial region. Multi-imaging modalities are available to assist in characterizing the structure of the lesion as well as its location and extent. This complex disease requires a multidisciplinary team approach with preoperative embolization and surgery. We present a rare cause of life-threatening epistaxis in a gentleman with a longstanding orbital and hemifacial arteriovenous malformation and discuss the complexities involved in its management.

Matched MeSH terms: Orbit/blood supply; Surgical Flaps/blood supply
Expression of Bax and Bcl-2 in tumour cells and blood vessels of breast cancer and their association with angiogenesis and hormonal receptors

Jaafar H, Abdullah S, Murtey MD, Idris FM

Asian Pac J Cancer Prev, 2012;13(8):3857-62.
PMID: 23098483

A total of 96 cases of invasive breast ductal carcinoma were examined for immunohistochemical expression of Bax and Bcl-2 in the epithelial tumor cells and endothelial cells of the blood vessels. We also investigated the association between both proteins in the epithelium in relation to tumor characteristics such as tumor size, grade, lymph node involvement, microvessel density (MVD), hormonal receptors expression and c-erbB-2 overexpression. Bax expression showed a significant association between tumor and endothelial cells (p<0.001) while Bcl-2 expression in tumor cells was inversely associated with that in the endothelial cells (p<0.001). Expression of Bcl-2 in tumor cells was strongly associated with expression of estrogen and progesterone receptors (p=0.003 and p=0.004, respectively). In addition, intratumoral MVD was significantly higher than peritumoral MVD (p<0.001) but not associated with Bax or Bcl-2 expression and other tumor characteristics. We concluded that the number of endothelial cells undergoing apoptosis was in direct linkage with the number of apoptotic tumor cells. Anti-apoptotic activity of the surviving tumor cells appears to propagate cancer progression and this was influenced by the hormonal status of the cells. Tumor angiogenesis was especially promoted in the intratumoral region and angiogenesis was independent of anti-apoptotic activity.

Matched MeSH terms: Breast Neoplasms/blood supply; Carcinoma, Ductal, Breast/blood supply
Characteristics of invasive breast ductal carcinoma, NOS, diagnosed in a tertiary institution in the East Coast of Malaysia with a focus on tumor angiogenesis

Ch'ng ES, Tuan Sharif SE, Jaafar H

Asian Pac J Cancer Prev, 2012;13(9):4445-52.
PMID: 23167359

BACKGROUND: Prognosis of breast cancer depends on classic pathological factors and also tumor angiogenesis. This study aimed to evaluate the clinicopathological factors of breast cancer in a tertiary centre with a focus on the relationship between tumor angiogenesis and clinicopathological factors.
METHODS: Clinicopathological data were retrieved from the archived formal pathology reports for surgical specimens diagnosed as invasive ductal carcinoma, NOS. Microvessels were immunohistochemically stained with anti-CD34 antibody and quantified as microvessel density.
RESULTS: At least 50% of 94 cases of invasive breast ductal carcinoma in the study were advanced stage. The majority had poor prognosis factors such as tumor size larger than 50mm (48.9%), positive lymph node metastasis (60.6%), and tumor grade III (52.1%). Higher percentages of estrogen and progesterone receptor negative cases were recorded (46.8% and 46.8% respectively). Her-2 overexpression cases and triple negative breast cancers constituted 24.5% and 22.3% respectively. Significantly higher microvessel density was observed in the younger patient age group (p=0.012). There were no significant associations between microvessel density and other clinicopathological factors (p>0.05).
CONCLUSIONS: Majority of the breast cancer patients of this institution had advanced stage disease with poorer prognostic factors as compared to other local and western studies. Breast cancer in younger patients might be more proangiogenic.

Matched MeSH terms: Breast Neoplasms/blood supply*; Carcinoma, Ductal, Breast/blood supply*
Fulltext β-Caryophyllene Induces Apoptosis and Inhibits Angiogenesis in Colorectal Cancer Models

Dahham SS, Tabana Y, Asif M, Ahmed M, Babu D, Hassan LE, et al.

Int J Mol Sci, 2021 Sep 29;22(19).
PMID: 34638895 DOI: 10.3390/ijms221910550

Beta-Caryophyllene (BCP), a naturally occurring sesquiterpene abundantly found in cloves, hops, and cannabis, is the active candidate of a relatively new group of vascular-inhibiting compounds that aim to block existing tumor blood vessels. Previously, we have reported the anti-cancer properties of BCP by utilizing a series of in-vitro anti-tumor-related assays using human colorectal carcinoma cells. The present study aimed to investigate the effects of BCP on in-vitro, ex-vivo, and in-vivo models of anti-angiogenic assays and evaluate its anti-cancer activity in xenograft tumor (both ectopic and orthotopic) mice models of human colorectal cancer. Computational structural analysis and an apoptosis antibody array were also performed to understand the molecular players underlying this effect. BCP exhibited strong anti-angiogenic activity by blocking the migration of endothelial cells, tube-like network formation, suppression of vascular endothelial growth factor (VEGF) secretion from human umbilical vein endothelial cells and sprouting of rat aorta microvessels. BCP has a probable binding at Site#0 on the surface of VEGFR2. Moreover, BCP significantly deformed the vascularization architecture compared to the negative control in a chick embryo chorioallantoic membrane assay. BCP showed a remarkable reduction in tumor size and fluorescence molecular tomography signal intensity in all the mice treated with BCP, in a dose-dependent relationship, in ectopic and orthotopic tumor xenograft models, respectively. The histological analysis of the tumor from BCP-treated mice revealed a clear reduction of the density of vascularization. In addition, BCP induced apoptosis through downregulation of HSP60, HTRA, survivin, and XIAP, along with the upregulation of p21 expressions. These results suggest that BCP acts at multiple stages of angiogenesis and could be used as a promising therapeutic candidate to halt the growth of colorectal tumor cells.

Matched MeSH terms: Colorectal Neoplasms/blood supply; Chorioallantoic Membrane/blood supply
Fulltext Diverse roles of prostaglandins in blastocyst implantation

Salleh N

ScientificWorldJournal, 2014;2014:968141.
PMID: 24616654 DOI: 10.1155/2014/968141

Prostaglandins (PGs), derivatives of arachidonic acid, play an indispensable role in embryo implantation. PGs have been reported to participate in the increase in vascular permeability, stromal decidualization, blastocyst growth and development, leukocyte recruitment, embryo transport, trophoblast invasion, and extracellular matrix remodeling during implantation. Deranged PGs syntheses and actions will result in implantation failure. This review summarizes up-to-date literatures on the role of PGs in blastocyst implantation which could provide a broad perspective to guide further research in this field.

Matched MeSH terms: Uterus/blood supply
Fulltext Periodic assessment of plasma sFlt-1 and PlGF concentrations and its association with placental morphometry in gestational hypertension (GH) - a prospective follow-up study

Jeevaratnam K, Nadarajah VD, Judson JP, Nalliah S, Abdullah MF

BMC Pregnancy Childbirth, 2010;10:58.
PMID: 20920154 DOI: 10.1186/1471-2393-10-58

Hypertensive disorders in pregnancy contributes to about 12% of maternal deaths in Malaysia and similarly worldwide. Early detection and adequate management are preventable strategies. Biochemical markers of abnormal angiogenesis would be more specific in early detection than routine blood pressure and proteinuria measurements. The aim of this study was to estimate maternal plasma PlGF and sFlt-1 levels in pregnant women with gestational hypertension at three intervals of pregnancy and correlate these biomarker levels with placental morphometry.

Matched MeSH terms: Placenta/blood supply
The use of glycerol-preserved skin allograft in conjunction with reconstructive and flap surgery: seven years of experience

Saad AZ, Halim AS, Khoo TL

J Reconstr Microsurg, 2011 Feb;27(2):103-8.
PMID: 20976667 DOI: 10.1055/s-0030-1268208

Major reconstructive surgery may be extensive and prolonged, and it may cause edema and compromise the flap pedicle if closed under tension. Glycerol-preserved skin allograft (GPA) can provide a means for tension-free closure and temporary cover of the wound. Seven years of analysis on GPA used in conjunction with major reconstruction was undertaken to highlight its indications, results, and outcomes. Forty-seven patients were included, aged between 9 and 73 years. Majority of patients had reconstruction following tumor resection and trauma. The main indication for use of GPA was temporary, loose cover of the wound in 44% of cases; flap pedicle protection in 31% of cases; donor site wound cover in 10%; flap monitoring in one case; and management of flap-related complications in 6% of cases. Free flap reconstruction was performed in 72% of cases. In conclusion, GPA is a useful adjunct in reconstructive surgery. It can be used temporarily to allow tension-free wound closure, as well as to protect the flap pedicle until edema subsides and the pedicle becomes stable. This latter approach allows secondary wound closure and good esthetic outcome.

Matched MeSH terms: Surgical Flaps/blood supply*
Comparison of heat dissipation response between Malaysian and Japanese males during exercise in humid heat stress

Wakabayashi H, Wijayanto T, Lee JY, Hashiguchi N, Saat M, Tochihara Y

Int J Biometeorol, 2011 Jul;55(4):509-17.
PMID: 20949285 DOI: 10.1007/s00484-010-0374-5

This study investigated the differences in heat dissipation response to intense heat stress during exercise in hot and humid environments between tropical and temperate indigenes with matched physical characteristics. Ten Japanese (JP) and ten Malaysian (MY) males participated in this study. Subjects performed exercise for 60 min at 55% peak oxygen uptake in 32°C air with 70% relative humidity, followed by 30 min recovery. The increase in rectal temperature (T(re)) was smaller in MY during exercise compared to JP. The local sweat rate and total body mass loss were similar in both groups. Both skin blood flow and mean skin temperature was lower in MY compared to JP. A significantly greater increase in hand skin temperature was observed in MY during exercise, which is attributable to heat loss due to the greater surface area to mass ratio and large number of arteriovenous anastomoses. Also, the smaller increase in T(re) in MY may be explained by the presence of a significantly greater core-skin temperature gradient in MY than JP. The thermal gradient is also a major factor in increasing the convective heat transfer from core to skin as well as skin blood flow. It is concluded that the greater core-skin temperature gradient observed in MY is responsible for the smaller increase in T(re).

Matched MeSH terms: Skin/blood supply
Classification of vascular function in upper limb using bilateral photoplethysmographic signals

Shariati NH, Zahedi E, Jajai HM

Physiol Meas, 2008 Mar;29(3):365-74.
PMID: 18367811 DOI: 10.1088/0967-3334/29/3/007

Bilateral PPG signals have been used for comparative study of two groups of healthy (free from any cardiovascular risk factors) and diabetic (as cardiovascular disease risk group) subjects in the age-matched range 40-50 years. The peripheral blood pulsations were recorded simultaneously from right and left index fingers for 90 s. Pulses have been modeled with the ARX440 model in the interval of 300 sample points with 100 sample points overlap between segments. Model parameters of three segments based on the highest fitness (higher than 80%) of modeled segments were retained for each subject. Subsequently, principal component analysis (PCA) was applied to the parameters of retained segments to eliminate the existing correlation among parameters and provide uncorrelated variables. The first principal component (contains 78.2% variance of data) was significantly greater in diabetic than in control groups (P < 0.0001, 0.74 +/- 2.01 versus -0.53 +/- 1.66). In addition the seventh principal component, which contains 0.02% of the data variance, was significantly lower in diabetic than in control groups (P < 0.05, -0.007 +/- 0.03 versus 0.005 +/- 0.03). Finally, linear discrimination analysis (LDA) was used to classify the subjects. The classification was done using the robust leaving-one-subject-out method. LDA could classify the subjects with 71.7% sensitivity and 70.2% specificity while the male subjects resulted in a highly acceptable result for the sensitivity (81%). The present study showed that PPG signals can be used for vascular function assessment and may find further application for detection of vascular changes before onset of clinical diseases.

Matched MeSH terms: Upper Extremity/blood supply*
Combination of vascularized outer-table calvarial bone graft based on the superficial temporal vessels and allomatrix for the repair of an orbito-frontal blow-out fracture in a child

Ali F, Halim AS, Najihah SZ, Ibrahim M, Abdullah J

J Craniomaxillofac Surg, 2005 Oct;33(5):326-30.
PMID: 16125400

A vascularized outer-table calvarial bone graft was used for repairing a Posnick type 2 traumatic orbito-frontal bone defect supported by the use of a calcium-based putty (Allomatrix) in a 7-year-old girl. Gaps between the donor and recipient sites were filled with Allomatrix containing demineralized bone matrix particles. Four years later there was a good cosmetic result using an artificial left eye.

Matched MeSH terms: Fascia/blood supply
Effect of des-aspartate-angiotensin I on the actions of angiotensin II in the isolated renal and mesenteric vasculature of hypertensive and STZ-induced diabetic rats

Dharmani M, Mustafa MR, Achike FI, Sim MK

Regul. Pept., 2005 Jul 15;129(1-3):213-9.
PMID: 15927718

The present study investigated the action of des-aspartate-angiotensin I (DAA-I) on the pressor action of angiotensin II in the renal and mesenteric vasculature of WKY, SHR and streptozotocin (STZ)-induced diabetic rats. Angiotensin II-induced a dose-dependent pressor response in the renal vasculature. Compared to the WKY, the pressor response was enhanced in the SHR and reduced in the STZ-induced diabetic rat. DAA-I attenuated the angiotensin II pressor action in renal vasculature of WKY and SHR. The attenuation was observed for DAA-I concentration as low as 10(-18) M and was more prominent in SHR. However, the ability of DAA-I to reduce angiotensin II response was lost in the STZ-induced diabetic kidney. Instead, enhancement of angiotensin II pressor response was seen at the lower doses of the octapeptide. The effect of DAA-I was not inhibited by PD123319, an AT2 receptor antagonist, and indomethacin, a cyclo-oxygenase inhibitor in both WKY and SHR, indicating that its action was not mediated by angiotensin AT2 receptor and prostaglandins. The pressor responses to angiotensin II in mesenteric vascular bed were also dose-dependent but smaller in magnitude compared to the renal vasculature. The responses were significantly smaller in SHR but no significant difference was observed between STZ-induced diabetic and WKY rat. Similarly, PD123319 and indomethacin had no effect on the action of DAA-I. The findings reiterate a regulatory role for DAA-I in vascular bed of the kidney and mesentery. By being active at circulating level, DAA-I subserves a physiological role. This function appears to be present in animals with diseased state of hypertension and diabetes. It is likely that DAA-I functions are modified to accommodate the ongoing vascular remodeling.

Matched MeSH terms: Kidney/blood supply
Fulltext Early complication following long bone reconstruction using vascularised fibula graft

Imran Y, Zulmi W, Halim AS

Med J Malaysia, 2004 Dec;59 Suppl F:35-8.
PMID: 15941158

Long bone reconstruction using vascularized fibula graft is becoming more popular despite the difficulties and its post-operative complications. We reviewed our early experience dealing with vascularized fibula graft for the management of massive long bone defect. Thirteen patients had undergone long bone reconstruction using vascularized fibula graft. Early complications that had been encountered include superficial wound infection (23%), transient common peroneal nerve palsy (23%), stage 1 bed sore (7.7%), anastomotic venous thrombosis (30.8%), DIVC (15.4%), flap loss and amputation (7.7%), and reactive psychiatric problem (7.7%). The early complications following this procedure are comparable with other major orthopaedic surgery and most of them are minor and treatable. The complication rates are also comparable with similar surgery done elsewhere.

Matched MeSH terms: Fibula/blood supply
Fulltext Versatility of the latissimus dorsi flap in upper limb salvage tumour surgery

Dorai AA, Halim AS, Zulmi W

Med J Malaysia, 2004 Dec;59 Suppl F:42-6.
PMID: 15941160

Reconstructive surgeons often encounter complex soft tissue and skeletal defects following oncological surgery. Soft tissue defects after wide resection in upper extremities posses a difficult challenge to find adequate tissue for reconstructing these defects. Paucity of local tissues dictates the requirement of loco-regional or distant flaps for these complex soft tissue defects which often exposes tendons, bones, nerves and joints. The latissimus dorsi muscle is a near ideal flap for the reconstruction because of the long neurovascular pedicle, ease of mobilization and its expendability. It can be rotated, with or without overlying skin, to cover soft tissue defects of the shoulder arm and elbow. Due to the large size of the muscle, it can be used to resurface the soft tissue defects and cover all major structures. Eleven consecutive cases were reviewed in which latissimus dorsi myocutaneous flap was used to reconstruct soft tissue defects of the upper limb following radical tumor resection. Flap survival was 100% with nominal donor site morbidity.

Matched MeSH terms: Muscle, Skeletal/blood supply
Anaerobic respiration: In vitro efficacy of Nitazoxanide against mitochondriate Acanthamoeba castellanii of the T4 genotype

Aqeel Y, Siddiqui R, Farooq M, Khan NA

Exp Parasitol, 2015 Oct;157:170-6.
PMID: 26297676 DOI: 10.1016/j.exppara.2015.08.007

Acanthamoeba is an opportunistic protist pathogen that is responsible for serious human and animal infection. Being one of the most frequently isolated protists from the environment, it is likely that it readily encounters microaerophilic environments. For respiration under anaerobic or low oxygen conditions in several amitochondriate protists, decarboxylation of pyruvate is catalyzed by pyruvate ferredoxin oxidoreductase instead of pyruvate dehydrogenase. In support, Nitazoxanide, an inhibitor of pyruvate ferredoxin oxidoreductase, is effective and non-mutagenic clinically against a range of amitochondriate protists, Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The overall aim of the present study was to determine in vitro efficacy of Nitazoxanide against Acanthamoeba castellanii. At micromolar concentrations, the findings revealed that Nitazoxanide neither affected A. castellanii growth or viability nor amoeba-mediated host cell monolayer damage in vitro or extracellular proteolytic activities. Similarly, microaerophilic conditions alone had no significant effects. In contrast, microaerophilic conditions together with Nitazoxanide showed amoebicidal effects and inhibited A. castellanii-mediated host cell monolayer damage as well as extracellular proteases. Using encystation assays, it was observed that Nitazoxanide inhibited trophozoite transformation into cysts both under aerophilic and microaerophilic conditions. Furthermore, pre-treatment of cysts with Nitazoxanide inhibited A. castellanii excystation. These findings are important in the identification of potential targets that could be useful against parasite-specific respiration as well as to understand the basic biology of the life cycle of Acanthamoeba.

Matched MeSH terms: Brain/blood supply

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links