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Biomedical subjects

A Farouk

Publications and source records attributed to A Farouk.

14 recordsLinked to original sources
PubMed2004

Molecular and physiological characterisation of a 3-phytase from soil bacterium Klebsiella sp. ASR1.

Klebsiella sp. strain ASR1 isolated from an Indonesian rice field is able to hydrolyse myo-inositol hexakis phosphate (phytate). The phytase protein was purified and characterised as a 42 kDa protein accepting phytate, NADP and sugar phosphates as substrates. The corresponding gene (phyK) was cloned from chromosomal DNA using a combined approach of protein and genome analysis, and expressed in Escherichia coli. The recombinant enzyme was identified as a 3-phytase yielding myo-inositol monophosphate, Ins(2)P, as the final product of enzymatic phytate hydrolysis. Based on its amino acid sequence, PhyK appears to be a member of a hitherto unknown subfamily of histidine acid phytate-degrading enzymes with the active site RHGXRXP and HD sequence motifs, and is different from other general phosphatases and phytases. Due to its ability to degrade sodium phytate to the mono phosphate ester, the phyK gene product is an interesting candidate for industrial and agricultural applications to make phytate phosphorous available for plant and animal nutrition.

Klebsiella↗
PubMed2003

Volatile constituents of glutathione--ribose model system and its antioxidant activity.

Reaction between glutathione and ribose was carried out to study the volatiles formed via Maillard reaction and their antioxidant activity as well as their role in inhibition of LDL oxidation. The simultaneous distillation-extraction technique was used for trapping the volatile components followed by GC-MS analysis. Thirty six compounds were identified with the predominance of carbonyls and sulfur-containing compounds in the volatiles of this model system. Sensory evaluation was performed for the model system product according to the International Standard Methods (ISO). The results showed a high decrease in roasted and burnt attributes and remarkable increase in the like-boiled and roasted meat attributes. The sensory results of the model system product were confirmed by the presence of high concentrations of some volatile compounds having meat--like aroma such as 2-methyl-3-furanthiol and 2-furylmethanethiol. The radical scavenging activity of glutathione-ribose model system was quantified spectrophotometrically, using DPPH radical. The activity of the model system product was found to be slightly lower than that of gallic acid and BHA, but it was much higher than that of cinnamic acid (200 ppm. for each). A highly antioxidative activity was recorded by the model system product during the inhibition of LDL-oxidation in comparison with L-ascorbic acid as well as reduced glutathione (as a concentration of 0.5 micromol/L, for each) which may be due to the presence of some compounds such as 2-furylmethanethiol, 2-acetyl thiazole, 4-hydroxy-5-methyl-3(2H)-furanone.

Antioxidants↗
PubMed2002

Caramelization of maltose solution in presence of alanine.

Two solutions of maltose in water were used to prepare caramels. Alanine as a catalyst was added to one of these solutions. The caramelization was conducted at 130 degrees C for total time period 90 minutes. Convenient samples were taken of each caramel solution every 30 min and subjected to sensory analysis and isolation of volatile components. The odour and colour sensory tests were evaluated according to the international standard methods (ISO). The results showed that, the presence of alanine gave rise to a high significant (P < 0.01) decrease in acid attributes and remarkable increase in the sweet and caramel attributes, which are the most important caramel notes. On the other hand the increase in heating time in presence of alanine as a catalyst resulted in a high significant (P < 0.01) increase in the browning rate of caramel solution. The new technique Solid Phase Micro Extraction (SPME) was used for trapping the volatile components in the headspace of each caramel samples followed by thermal desorption and GC and GC - MS analysis. The 5-hydroxymethyl-2-furfural (HMF), the main characteristic caramel product, showed its highest value in sample containing alanine after heating for 60 minutes. The best sensory results of the sample contains alanine were confirmed by the presence of high concentrations of the most potent odorants of caramel besides to the formation of some volatile compounds have caramel like flavours such as 2-acetyl pyrrole, 2-furanones and 1-(2-furanyl)1,2-propandione.

Alanine↗
PubMed2002

Low-flow priapism: risk factors for erectile dysfunction.

OBJECTIVE: To evaluate our policy of managing priapism for the success rate of the treatments, potency afterward, complications, and the risk factors responsible for erectile dysfunction in these patients. PATIENTS AND METHODS: The study included 50 patients (mean age 37.1 years, range 22-66) with a diagnosis of priapism (1981-1999). Their records were reviewed; 35 patients were available for a long-term evaluation. Factors assessed were the duration of priapism, history of previous recurrent attacks, possible underlying causes (e.g. haematological disorders, medications or trauma), relation to sexual stimulation, pain, and any attempt at previous management. A complete blood screen and blood gases were assessed in corporal aspirates. Duplex ultrasonography was used in all impotent patients at their follow-up. Early and late complications were reviewed, and patients asked about their erectile function before priapism, and any recurrence. RESULTS: The median (range) duration of priapism was 48 (6-240) h; almost half the patients presented > 48 h after the onset of priapism. Sixteen patients (32%) reported a history of previous recurrent attacks, of whom seven had a history of previous treatments. The main cause of priapism was idiopathic or intracavernosal injection with papaverine. All patients were initially treated by corporal blood aspiration and injection with ephedrine; if this failed or if the priapism was prolonged (> 48 h) various shunts were used. The hospital stay was significantly shorter among patients with papaverine-induced or brief priapism. In the long-term follow-up of 35 patients (mean 66.4 months, range 3-220) only 15 (43%) reported preserved erectile function, and this was more likely in patients with brief priapism (< 48 h). Eight patients (23%) reported subsequent recurrent attacks of priapism; all were managed successfully as they presented shortly after their onset. Penile fibrosis was detected in 20 patients (57%), and was significantly more common in those with prolonged priapism (> 48 h) or from causes other than papaverine. The 20 impotent men evaluated by Doppler ultrasonography had severe echo-dense penile fibrosis and high end-diastolic velocities suggesting veno-occlusive incompetence in all except two. In five men with shunts cavernosography showed extensive venous leakage irrespective of site of the shunt. MRI in five patients with penile fibrosis showed heterogeneous areas of low signal intensity, corresponding with haemosiderin deposition and fibrosis. On univariate analysis the final result of management (complete detumescence or not), the duration of priapism and the presence of penile fibrosis significantly influenced erectile function. On multivariate logistic regression only the first remained significant. CONCLUSIONS: Low-flow priapism for > 48 h, failure to maintain complete detumescence after management, and marked penile fibrosis during the follow-up are the most significant risk factors responsible for erectile dysfunction, with failure to achieve complete detumescence the most detrimental.

Adult↗
PubMed2001

Serum activin A and follistatin in disorders of spermatogenesis in men.

OBJECTIVE: Inhibin, activin and follistatin are glycoprotein hormones produced by the gonads. Recent studies have shown that inhibin B is the predominant form of inhibin in the circulation in men. The objective of this study was to investigate circulating levels of activin A and follistatin in disorders of spermatogenesis in men and their relationship with FSH and inhibin B. DESIGN AND METHOD: Serum from five different groups of men was prospectively collected and stored at -20 degrees C. The groups were men with: (i) proven fertility (controls) (n=20), (ii) primary testicular failure (n=15), (iii) obstructive azoospermia (n=10), (iv) oligospermia (n=10) and (v) miscellaneous sperm dysfunction (n=40). WHO criteria (1992) were used for semen characterisation. Serum concentrations of 'total' activin A, follistatin, FSH and inhibin B were measured using specific two-site enzyme immunoassays. RESULTS: Activin A levels were significantly lower than in the controls in the obstructive azoospermia group and higher in the miscellaneous sperm dysfunction group. Serum follistatin levels did not significantly vary in any group compared with the controls. Circulating levels of FSH were higher than in the controls in the primary testicular failure and obstructive azoospermic group. Levels of inhibin B were lower than in the controls in all disorders of spermatogenesis studied. CONCLUSION: This study demonstrates that activin A and follistatin are in the circulation in males and activin A levels are significantly lower in obstructive azoospermia and higher in miscellaneous sperm dysfunction than in controls. The mechanism involved in altering the levels of activin A in these conditions is not clear. However, high follistatin:activin A molar ratios (>2.5) in all groups suggests that all activin A in the circulation is bound to follistatin in males.

Activins↗
PubMed2000

Effect of amino acids on the composition and properties of extruded mixtures of wheat flour and glucose.

Wheat flour was extruded at 100-120 degrees C with 5% D-glucose or mixtures of 5% D-glucose and 0.5% or 2.0% of L-alanine, L-leucine, L-lysine, L-threonine or L-cysteine. The extent of browning was only moderate, and yellow and red pigments were produced. The odour intensity increased with the addition of either glucose or a mixture of glucose and amino acids; the odour was not significantly intensive according to sensory acceptancy analysis. The odour profile was influenced by the structure of amino acid present in the extruded material. The addition of D-glucose increased the production of furan derivatives, and in lesser degree, of pyrazines in the extruded product. The pyrazine content increased with the addition of amino acids, except cysteine which enhanced the production of sulphur compounds instead of pyrazines. The composition of the pyrazine fraction varied depending on the amino acid added. Pretreatment of D-glucose with an amino acid in aqueous solution affected the composition of volatiles, but it did not significantly enhance the pyrazine production.

Amino Acids↗
PubMed2000

Comparative studies on the in vitro properties of phytases from various microbial origins.

The physical and chemical properties of six crude phytase preparations were compared. Four of these enzymes (Aspergillus A, Aspergillus R, Peniophora and Aspergillus T) were produced at commercial scale for the use as feed additives while the other two (E. coli and Bacillus) were produced at laboratory scale. The encoding genes of the enzymes were from different microbial origins (4 of fungal origin and 2 of bacterial origin, i.e., E. coli and Bacillus phytases). One of the fungal phytases (Aspergillus R) was expressed in transgenic rape. The enzymes were studied for their pH behaviour, temperature optimum and stability and resistance to protease inactivation. The phytases were found to exhibit different properties depending on source of the phytase gene and the production organism. The pH profiles of the enzymes showed that the fungal phytases had their pH optima ranging from 4.5 to 5.5. The bacterial E. coli phytase had also its pH optimum in the acidic range at pH 4.5 while the pH optimum for the Bacillus enzyme was identified at pH 7.0. Temperature optima were at 50 and 60 degrees C for the fungal and bacterial phytases, respectively. The Bacillus phytase was more thermostable in aqueous solutions than all other enzymes. In pelleting experiments performed at 60, 70 and 80 degrees C in the conditioner, Aspergillus A, Peniophora (measurement at pH 5.5) and E. coli phytases were more heat stable compared to other enzymes (Bacillus enzyme was not included). At a temperature of 70 degrees C in the conditioner, these enzymes maintained a residual activity of approximately 70% after pelleting compared to approximately 30% determined for the other enzymes. Incubation of enzyme preparations with porcine proteases revealed that only E. coli phytase was insensitive against pepsin and pancreatin. Incubation of the enzymes in digesta supernatants from various segments of the digestive tract of hens revealed that digesta from stomach inactivated the enzymes most efficiently except E. coli phytase which had a residual activity of 93% after 60 min incubation at 40 degrees C. It can be concluded that phytases of various microbial origins behave differently with respect to their in vitro properties which could be of importance for future developments of phytase preparations. Especially bacterial phytases contain properties like high temperature stability (Bacillus phytase) and high proteolytic stability (E. coli phytase) which make them favourable for future applications as feed additives.

6-Phytase↗
PubMed1999

Predictors of nocturnal oxygen desaturation in patients with COPD.

The aim of this study was to identify factors which might predict nocturnal desaturation (defined as a fall of > 4% from awake baseline level for > or = 5 min) in normoxic or mildly hypoxic patients with stable COPD [arterial O2 saturation (SaO2) > or = 91%]. The study was prospective in nature, had full ethical approval and was performed in the Respiratory Department of a city teaching hospital. Thirty-three patients [mean (SD) age 67.2 (9) years] with stable COPD [mean (SD) FEV1 36.8 (11.0)% pred.] were recruited via the respiratory outpatient clinics and through the respiratory wards. The following parameters were measured: daytime arterial blood gases; spirometry; lung volumes (helium dilution); single breath CO transfer factor (TLCO and KCO); maximum inspiratory (IMP) and expiratory mouth pressures; pulse oximetry (SpO2) across a 6-min walk test, and SpO2 during sleep. Seventeen patients who experienced nocturnal desaturation had significantly lower mean PaO2 and SaO2, and higher PaCO2 values compared to non-desaturators. There was a positive correlation between mean nocturnal SpO2 and daytime PaO2, SaO2, and minimum exercise SpO2, and a negative correlation between mean nocturnal SpO2 and PaCO2, and FRC. Regression analysis revealed that daytime SaO2 was the only independent predictor of mean nocturnal saturation (accounting for 61% of the variability in the mean nocturnal SpO2). We observed nocturnal desaturation in all patients with a daytime SaO2 < or = 93% but in no patient with SaO2 > or = 95%. We conclude that daytime SaO2 can be used to predict nocturnal desaturation in normoxic or mildly hypoxic patients with stable COPD. Nocturnal desaturation is likely in patients with COPD where daytime SaO2 < or = 93%, and unlikely where daytime SaO2 > or = 95%.

Exercise↗
PubMed1998

Endoscopic neurosurgery: report of the first five cases done in Malaysia using the Caemaert-Abdullah method.

The first endoscopic procedure done in Malaysia using the Caemaert-Abdullah method is reported and the followup results showed an excellent neurosurgical outcome. A 16-year-old girl with an aqueduct stenosis was operated on using a free-hand, computer-assisted endoscopic method where a third ventriculostomy was done. This was the first case being carried out in the Hospital Universiti Sains Malaysia. The next two cases were a suprasellar pituitary cyst in an elderly man and a child with an obstructive hydrocephalus who was previously shunted which became infected. Both endoscopic procedures, extirpation of the cyst using a Nd:Yag laser and a third ventriculostomy, respectively, were done under general anaesthesia in the supine position. Follow-up revealed a transient diabetes insipidus in all three cases up to 48 hours after the operation which resolved spontaneously. The fourth case involved an endoscopic removal of retained ventricular catheter after rectal migration of a shunt in an eight-year-old girl with congenital hydrocephalus. The fifth was a free-hand endoscopy with perforation of multiple brain septae in a ten-month-old baby with hydrocephalus secondary to meningitis. The final outcomes for all the cases were favourable hence we conclude that endoscopic neurosurgery is a safe procedure and hope that more neurosurgeons will continue to use this method, especially for the management of intraventricular cyst and hydrocephalus and especially in South East Asia.

Adolescent↗
PubMed1989

Bioactivity of some chemotherapeutic agents in selected polyethylene glycol ointment bases.

Six different chemotherapeutic agents were individually incorporated in each of fourteen selected polyethylene glycol ointment bases, and their bioactivities were assessed using different diffusion techniques. The prepared medicated ointments were evaluated for drug release using the standard microbiological agar cup diffusion, the long period method and the short period method, as well as dialysis through artificial kidney membrane. On the basis of consistency, stability and diffusion results, formulation 11 was the most suitable base for ampicillin, formulation 14 for oxytetracycline HCl, formulation 10 and 9 for neomycin sulphate, and preparation 10 for chloramphenicol. On the basis of the results of drug release, it was evident that formulation 3 was the best for ampicillin and chloramphenicol, formulation 2 for erythromycin, formulation 4 for neomycin sulphate, formulation 12 for sulphadimidine, and formulation 14 for oxytetracycline HCl.

Anti-Bacterial Agents↗
PubMed1986

Potential antimalarial candidates from African plants: and in vitro approach using Plasmodium falciparum.

Twenty-one compounds isolated from nine medicinal plants used in traditional medicine in the Sudan and other African countries were examined in vitro for antimalarial activity against Plasmodium falciparum, the major human malaria parasite. Compounds tested include alkaloids, lignans, triterpenes, coumarins, limonoids and flavonoids. Most were relatively inactive; one limonoid, gedunin, had an IC50 value of about 1 microM after 48 h exposure (0.3 microM after 96 h), roughly equivalent to quinine. In this protocol, the flavonoid quercetin purified from Diosma pilosa was found to have the same activity as a commercially obtained preparation. Simple radiometric assays for antimalarial activity can thus be used to rapidly screen purified plant material or secondary plant metabolites. The high potency and efficacy of quinine and the Chinese herbal antimalarial quinghaosu (artemisinine) illustrate the merit of this approach.

Africa↗
PubMedDate not supplied

Diuretic contrast-enhanced magnetic resonance urography versus intravenous urography for depiction of nondilated urinary tracts.

Diuretic contrast-enhanced magnetic resonance urography (MRU) is analogous to conventional intravenous urography (IVU) and, hence, designated as excretory MRU. It is performed with a T1-weighted fast gradient-echo sequence to obtain breath-hold, dynamic MRU after intravenous injection of low-dose furosemide (5-10 mg) and gadolinium (Gd) chelate. The combination of Gd and furosemide is the key for achieving a uniform distribution of the contrast material inside the entire urinary tract. It provides high-resolution images of nondilated urinary tracts and information about the renal function. This pictorial essay reviews the technical aspects and practical consideration of diuretic Gd-enhanced MRU and underlines its diagnostic capability in comparison with IVU in the depiction of nondilated collecting systems. We discuss its potential applications, as in young patients with anatomic anomalies, patients with renal transplants, patients allergic to iodinated contrast medium, and avoiding multimodality work-up in the evaluation of kidney donors and patients with renal and extrarenal tumor diseases.

Adult↗