Biomedical subjects

N Abdullah

Publications and source records attributed to N Abdullah.

At least 19 recordsLinked to original sources

PubMed2005

Removal of poly-histidine fusion tags from recombinant proteins purified by expanded bed adsorption.

Enzymatic methods have been used to cleave the C- or N-terminus polyhistidine tags from histidine tagged proteins following expanded bed purification using immobilized metal affinity chromatography (IMAC). This study assesses the use of Factor Xa and a genetically engineered exopeptidase dipeptidyl aminopeptidase-1 (DAPase-1) for the removal of C-terminus and N-terminus polyhistidine tags, respectively. Model proteins consisting of maltose binding protein (MBP) having a C- or N-terminal polyhistidine tag were used. Digestion of the hexahistidine tag of MBP-His(6) by Factor Xa and HT15-MBP by DAPase-1 was successful. The time taken to complete the conversion of MBP-His(6) to MBP was 16 h, as judged by SDS-PAGE and Western blots against anti-His antibody. When the detagged protein was purified using subtractive IMAC, the yield was moderate at 71% although the overall recovery was high at 95%. Likewise, a yield of 79% and a recovery of 97% was obtained when digestion was performed with using "on-column" tag digestion. On-column tag digestion involves cleavage of histidine tag from polyhistidine tagged proteins that are still bound to the IMAC column. Digestion of an N-terminal polyhistidine tag from HT15-MBP (1 mg/mL) by the DAPase-I system was superior to the results obtained with Factor Xa with a higher yield and recovery of 99% and 95%, respectively. The digestion by DAPase-I system was faster and was complete at 5 h as opposed to 16 h for Factor Xa. The detagged MBP proteins were isolated from the digestion mixtures using a simple subtractive IMAC column procedure with the detagged protein appearing in the flowthrough and washing fractions while residual dipeptides and DAPase-I (which was engineered to exhibit a poly-His tail) were adsorbed to the column. FPLC analysis using a MonoS cation exchanger was performed to understand and monitor the progress and time course of DAPase-I digestion of HT15-MBP to MBP. Optimization of process variables such as temperature, protein concentration, and enzyme activity was developed for the DAPase-I digesting system on HT15-MBP to MBP. In short, this study proved that the use of either Factor Xa or DAPase-I for the digestion of polyhistidine tags is simple and efficient and can be carried out under mild reaction conditions.

Carrier Proteins↗

PubMed2005

Effects of beta-glucanase-producing Lactobacillus strains on growth, dry matter and crude protein digestibilities and apparent metabolisable energy in broiler chickens.

The effects of beta-glucanase expressed by transformed Lactobacillus strains on growth performance, apparent digestibilities of dry matter and crude protein, and apparent metabolisable energy were studied. Two hundred and forty 1-d-old chicks (Avian-43) were randomly divided into three dietary treatment groups and fed with the following diets: (i) basal diet (control) (BD); (ii) basal diet with parental Lactobacillus strains (BDP) and (iii) basal diet with transformed Lactobacillus strains (BDT). At 21 d of age, the body weight, body weight gain and feed conversion ratio of the BDT-fed chickens were significantly improved. At 14 and 21 d of age, the proportions of dry matter in the duodenum, jejunum, ileum, caeca and excreta of chickens given the BDT diet were significantly higher than those of chickens given the BD and BDP diets. Apparent metabolisable energy, digestibilities of crude protein and dry matter were also significantly improved (by 3.5, 5.6 and 3.5%, respectively) by the BDT diet. These results showed that the transformed Lactobacillus strains improved digestibility as well as enhanced the growth performance of chickens.

Animal Feed↗

PubMed2005

Influence of beta-glucanase-producing Lactobacillus strains on intestinal characteristics and feed passage rate of broiler chickens.

Two experiments were conducted to study the effects of beta-glucanase produced by transformed Lactobacillus strains on the intestinal characteristics and feed passage rate of broiler chickens fed barley-based diets. Supplementation of transformed Lactobacillus strains to the diet of chickens significantly (P < 0.05) reduced the intestinal fluid viscosity by 21 to 46% compared with chickens fed an unsupplemented diet or a diet supplemented with parental Lactobacillus strains. The relative weights of pancreas, liver, duodenum, jejunum, ileum, ceca, and colon were reduced (P < 0.05) by 6 to 27%, and the relative length of duodenum, jejunum, ileum, and ceca was reduced (P < 0.05) by 8 to 15%. Histological examination of the intestinal tissues showed that the jejunal villus height of chickens fed a diet supplemented with transformed Lactobacillus strains was significantly (P < 0.05) higher than that of chickens fed other dietary treatments. The transformed Lactobacillus strains were found to reduce (P < 0.05) the time of feed passage rate by 2.2 h. Supplementation of transformed Lactobacillus strains to the diet improved the intestinal characteristics and feed, passage rate of the chickens.

Animal Feed↗

PubMed2005

Primary hyperaldosteronism with normokalaemia secondary to an adrenal adenoma (Conn's syndrome) in a 12 year-old boy.

A 12-1/2 year-old boy presented to the Accident Department following an episode of dizziness and was found to be hypertensive. Investigations revealed primary hyperaldosteronism secondary to an adrenal adenoma (Conn's syndrome). He had normal electrolytes during the period of investigation and potassium concentrations were > or = 4.2 mmol/l on all but one occasion. The hypertension resolved following excision of the adrenal tumour. Normokalaemia with potassium >4.0 mmol/l is very unusual in patients with Conn's syndrome and has not been described in childhood before. Primary hyperaldosteronism needs to be considered in hypertensive children even when potassium concentrations are well within the laboratory reference range.

Adolescent↗

PubMed2004

The inframammary fold: contents, clinical significance and implications for immediate breast reconstruction.

The amount of breast tissue within the inframammary fold (IMF) is controversial. Preservation of the IMF during mastectomy facilitates breast reconstruction and led some surgeons to practice conservation of the IMF, contrary to traditional descriptions of total mastectomy. The aim of this study was to analyse the clinical significance of IMF tissue content. A total of 50 IMF specimens were studied from 42 patients who underwent mastectomy between January 2001 and December 2002. The amount of breast tissue within each IMF was evaluated. The median patient age was 46 (range 33-86) years. The median body mass index was 23.4 (18.1-38.3)kg/m(2). The median IMF volume resected was 2 (0.2-9.7)cm(3) which was 0.6 (0.1-2.0)% of the breast volume. Ten specimens (20%) contained breast tissue and one (2%) contained breast tissue and an inframammary lymph node. Three specimens (6%) containing fibrofatty tissue without breast parenchyma had intramammary lymph nodes within the IMF. One patient (2%) who had a mastectomy for invasive ductal carcinoma had IMF tissue containing a lymph node within the IMF with breast cancer metastasis. The presence of breast tissue or lymph nodes within the IMF was unrelated to patient age, body mass index, the amount of IMF tissue in relation to breast volume and absolute breast size. Our finding that breast tissue and intramammary lymph nodes are present in 28% of IMF specimens requires re-consideration of the safety of preserving the IMF at mastectomy. If IMF tissue is resected and the immediate breast reconstruction is performed, the superficial fascial system should be reconstructed after excision of the IMF tissue in order to recreate the inframammary crease.

Adult↗

PubMed2004

Measurement of tumour size in case selection for breast cancer therapy by clinical assessment and ultrasound.

AIMS: Clinical assessment of tumour size is often used to choose between mastectomy and primary medical therapy. Clinical and imaging modalities may have varying levels of accuracy across the range of tumour sizes. The aim of this study was to compare the accuracy of clinical measurement and ultrasound in discriminating palpable tumours up to 3 cm vs those greater than 3 cm. METHODS: A prospective analysis of 111 consecutive patients with palpable breast cancer was performed. All women had clinical measurement by caliper and ultrasound assessment prior to any needle biopsy. Clinical measurement and ultrasound assessment of size were compared to pathological tumour size of the surgical specimen. RESULTS: Both clinical and ultrasound measurement underestimate the size of larger tumours. The overall accuracy of clinical assessment and ultrasound examination in correctly identifying a 30 mm cut off was 70.3 and 77.5%, respectively. Ultrasound was significantly more accurate at determining the size of tumours <30 mm (p=0.007) but there was no significant difference between both modalities in assessing tumours greater than 30 mm. CONCLUSIONS: Ultrasound assessment of breast cancer size is more accurate than clinical assessment for tumours less than 30 mm. As clinical examination is as accurate on ultrasound for tumours greater than 30 mm, clinical assessment of tumour size alone is adequate to select patients for primary medical therapy or mastectomy.

Adult↗

PubMed2004

Surface properties and microporosity of polyhydroxybutyrate under scanning electron microscopy.

This study was designed to investigate the surface properties especially surface porosity of polyhydroxybutyrate (PHB) using scanning electron microscopy. PHB granules were sprinkled on the double-sided sticky tape attached on a SEM aluminium stub and sputtered with gold(10nm thickness) in a Polaron SC515 Coater, following which the samples were placed into the SEM specimen chamber for viewing and recording. Scanning electron micrographs with different magnification of PHB surface revealed multiple pores with different sizes.

Biocompatible Materials↗

PubMed2003

Squamous cell carcinoma of the breast: clinico-pathologic implications and outcome.

AIMS: Pure squamous cell carcinoma (SCC) of the breast is a rare tumour and little is known about long-term outcome. We report our experience of a consecutive series of patients. METHODS: All patients with SCC treated at our institution between 1970 and 2001 were included. The pathological features, outcome and prognosis were studied. RESULTS: Eleven patients were identified. The median age was 55 (38-90) years and median follow-up was 62 (3-332) months. Four tumours were T1, three were T2 and three were T3 (one tumour size was unknown). There were seven poorly differentiated and three moderately differentiated SCC. Tumour grade could not be assessed in one patient. Primary treatment was mastectomy in six patients, wide local excision in four patients and radiotherapy in one patient. There was lymph node (LN) involvement in two patients. Oestrogen receptor status was assessed in seven patients and only one tumour was positive. Adjuvant chemotherapy was given to three patients and five patients received adjuvant radiotherapy. Two patients developed local recurrence at 5 and 12 months and three patients developed distant metastasis at 2, 36 and 306 months. Three patients were treated with chemotherapy at recurrence. Three patients have died of the disease, two are alive with disease and six remain well. The 2- and 5-year overall survival was 80% (SE=13%) and 67% (SE=16%) respectively. Large tumour size and positive LN status were prognostic indicators of poor outcome. CONCLUSION: SCC of the breast adopts an aggressive course with outcome comparable to poorly differentiated breast adenocarcinoma.

Adult↗

PubMed2003

Effects of Lactobacillus cultures on growth performance, abdominal fat deposition, serum lipids and weight of organs of broiler chickens.

1. The effects of a mixture of 12 Lactobacillus strains (LC) on the growth performance, abdominal fat deposition, serum lipids and weight of organs of broiler chickens were studied from 1 to 42 d of age. 2. One hundred and thirty-six 1-d-old male broiler chicks were assigned at random to two dietary treatments: a basal diet (control), and a basal diet with 0.1% LC. 3. The supplementation of LC in broiler diets improved the body weight gain and feed conversion rate from 1 to 42 d of age and was effective in reducing abdominal fat deposition but only after 28 d of age. 4. The LC diets reduced serum total cholesterol, low density lipoprotein (LDL) cholesterol and triglycerides in broilers from 21 to 42 d of age. However, there was no significant difference in serum high density lipoprotein (HDL) cholesterol between control and LC-fed broilers. There was also no significant difference in the weights of organs of control and LC-fed broilers. 5. The results indicated that the mixture of 12 Lactobacillus strains have a hypolipidaemic effect on broilers.

Abdomen↗

PubMed2002

Culture conditions influencing phytase production of Mitsuokella jalaludinii, a new bacterial species from the rumen of cattle.

AIMS: The effects of pH, temperature, phytate, glucose, phosphate and surfactants on the phytase production of Mitsuokella jalaludinii, a new bacterial species from the rumen of cattle, were evaluated. METHOD AND RESULTS: By using batch fermentation, it was found that phytase production of M. jalaludinii was induced by sodium phytate. Inclusion of glucose into rice bran-soybean milk (RB-SM) medium inhibited the phytase production. Supplementation of 0.05-0.5% of phosphate to RB-SM medium neither inhibited nor stimulated the phytase production. The optimum pH and temperature for the phytase production of M. jalaludinii were 7.02 and 39 degrees C, respectively. Surfactants such as Tween-80 (0.5% and 1.0%) and Triton X-100 (1.0%) did not affect the phytase production. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The study has provided important data on the culture conditions affecting phytase production of M. jalaludinii, which will facilitate future research on the optimization of fermentation processes for production of high phytase activity by M. jalaludinii.

6-Phytase↗

PubMed2002

Optimization of carbon and nitrogen sources for phytase production by Mitsuokella jalaludinii, a new rumen bacterial species.

AIMS: The effects of different carbon and nitrogen sources on phytase production by Mitsuokella jalaludinii were evaluated and the optimization of rice bran (RB) and soybean milk (SM) concentrations in the medium for phytase production was also determined. METHODS AND RESULTS: Replacement of glucose, cellobiose and starch in MF1 medium by RB or palm kernel cake and replacement of trypticase peptone and yeast extract in the medium by SM or enzymatic digested soybean milk significantly increased the phytase production by M. jalaludinii. The optimal concentrations of RB and SM in the medium for phytase production were 15% RB and 20% SM or 20% RB and 10% SM or 20% RB and 20% SM and the phytase activities in the media were 12.53, 12.93 and 12.75 U g-1 culture broth, respectively. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The high production of phytase by M. jalaludinii warrants further research to increase its yield by genetic manipulation for commercial application.

6-Phytase↗

PubMed2002

Efficacy of supplementation of a phytase-producing bacterial culture on the performance and nutrient use of broiler chickens fed corn-soybean meal diets.

We evaluated the efficacy of supplementation of active Mitsuokella jalaludinii culture (AMJC) on the growth performance, nutrient use, and mineral concentrations in tibia bone and plasma of broiler chickens fed corn-soybean meal diets. Dietary treatments included low-nonphytate P (NPP) feed (containing 0.24% and 0.232% NPP for chicks from 1 to 21 and 22 to 42 d of age, respectively), low-NPP feed added with different levels of AMJC (equivalent to 250, 500, 750, and 1,000 U phytase/kg of feed), and normal-NPP feed (containing 0.46 and 0.354% NPP for chicks from 1 to 21 and 22 to 42 d of age, respectively). Supplementation of AMJC to low-NPP feed increased (P < 0.05) weight gain and feed intake and decreased (P < 0.05) feed:gain ratio of chickens during the whole experiment (Days 1 to 42). Supplementation of AMJC increased (P < 0.05) the AME value, digestibility of DM and CP, and retention of P, Ca, and Cu. Mn retention in broilers was only increased (P < 0.05) by AMJC supplementation from 18 to 20 d of age, and Zn retention was improved (P < 0.05) only at a high level of AMJC (equivalent to 1,000 U phytase/kg of feed) supplementation. Chicks fed low-NPP feed added with AMJC had similar tibia ash percentages as those fed the normal-NPP diet. Generally, supplementing AMJC to low-NPP feed increased (P < 0.05) Ca, decreased significantly (P < 0.05) Mn and Cu, but did not affect Zn and P concentrations in tibia ash. Supplementing AMJC also increased (P < 0.05) plasma P but had no effect on plasma Ca or Mn. Plasma Zn concentration was increased only when a high level of AMJC (equivalent to 1,000 U phytase/kg of feed) was used. In conclusion, AMJC supplementation to low-NPP feed improved growth performance; AME value; digestibility of CP and DM; use of Ca, P, and Cu; and bone mineralization.

6-Phytase↗

PubMed2002

Mitsuokella jalaludinii sp. nov., from the rumens of cattle in Malaysia.

Five strains of phytase-producing, gram-negative, non-spore-forming, non-motile, small, stout, rod-shaped, strictly anaerobic, fermentative bacteria were isolated from the rumens of cattle in Malaysia. All five strains had morphological, physiological and biochemical features in common. Although these strains had many physiological and biochemical characteristics that were identical to those of the Mitsuokella multacida type strain (ATCC 27723T), they could be distinguished from this species by means of the following characteristics: a smaller cell size (1.2-2.4 microm long and 0.6-0.8 microm wide); a lower final pH value (3.8-4.0) in peptone/yeast extract/glucose broth; inhibition by 0.001% brilliant green; insensitivity to kanamycin (100 microg ml(-1)) and penicillin (10 microg ml(-1)); a higher optimum growth temperature (approx. 42 degrees C); the ability to grow at 45 and 47 degrees C; the ability to ferment glycerol, sorbitol and amidon; and the inability to ferment mannitol, rhamnose, D-tagatose and melezitose. The G+C content of the type strain (M 9T) of these five strains was 56.9 mol%. Analysis of the 16S rRNA gene sequence of type strain M 9T indicated that the strain falls within the genus Mitsuokella. The sequence similarity between type strain M 9T and Mitsuokella multacida was 98.7%. The DNA-DNA relatedness between type strain M 9T and Mitsuokella multacida type strain DSM 20544T (= ATCC 27723T) was 63.8%, indicating that, in spite of a high level of similarity for the 16S rRNA gene sequence, type strain M 9T is independent of Mitsuokella multacida at the species level. On the basis of these results, a new species, Mitsuokella jalaludinii sp. nov., is proposed for these strains. The type strain is M 9T (= DSM 13811T = ATCC BAA-307T).

6-Phytase↗

PubMed2001

Energy expenditure in relation to activity of lesser mouse deer (Tragulus javanicus).

Heat production (HP) of male and female mouse deer during eating, standing and sitting was determined using the open circuit respiration chamber (RC). The time taken for similar activities was also determined in an outdoor enclosure (OD). The animals were fed kangkong (Ipomoea aquatica), sweet potato (Ipomoea batatas) and rabbit pellet ad libitum. Male mouse deer consumed more dry matter (DM), organic matter (OM) and gross energy (GE) than female. The time for each activity of male and female mouse deer kept in RC and OD was similar. The average time spent in RC and OD for both male and female, respectively, for sitting (956 and 896 min/day) was significantly (P<0.01) longer than standing (463 and 520 min/day) and eating (21 and 24 min/day). Heat production for male and female mouse deer, respectively, during eating was the highest (0.44 and 0.43 kJ/kg W(0.75)/min) followed by standing (0.37 and 0.33 kJ/kgW(0.75)/min) and sitting (0.26 and 0.26 kJ/kg W(0.75)/min). The difference in HP per min during standing between male and female was significant (P<0.05). The HP for 08.00-14.00 h and 14.00-20.00 h periods were higher than 20.00-02.00 h and 02.00-08.00 h periods. The overall HP for males during 08.00-14.00 h and 14.00-20.00 h periods were significantly (P<0.05) higher (114.8 and 119.2 kJ/kg W(0.75)) than female (107.5 and 110.4 kJ/kg W(0.75)), respectively.

Animals↗

PubMed2000

Skin prick test reactivity to foods in adult Malaysians with rhinitis.

The aim of the study was to determine the incidence of food and house dust mite (HDM) allergy in patients with nasal congestion and rhinorrhea attending the Otorhinolaryngology Clinic, National University of Malaysia, Kuala Lumpur. This was a prospective matched, controlled study of patients skin prick tested with commercial food and common aeroallergens. The participants were 148 Malaysian adults with symptoms of nasal congestion and rhinorrhea and 113 adult Malaysian control subjects without rhinitis symptoms. The skin prick test (SPT) was used to evaluate 11 foods common to the Malaysian diet and 3 HDM inhalants. Forty-eight percent of the patients with rhinitis had positive SPT results to foods, compared with 4.4% of control subjects (P < 0.05). The most commonly implicated foods were shrimp (48%) and rice (30%), which are common in the Malaysian diet. Seventy-two percent of rhinitis patients had positive SPT results to HDM, compared with 22.2% of control subjects (P < 0.05). Patients with rhinitis also had significantly more gastrointestinal problems than control subjects (P < 0.05). The incidences of HDM and food allergy are significantly greater in Malaysian adults with rhinitis symptoms than in control subjects without rhinitis. The effect of avoidance or immunotherapy awaits further study.

Adolescent↗

PubMed2000

Digestive and bacterial enzyme activities in broilers fed diets supplemented with Lactobacillus cultures.

A study was carried out to investigate the effects of adherent Lactobacillus cultures on 1) amylolytic, lipolytic, and proteolytic enzyme activities in the contents of the small intestine (from the distal end of the duodenum to the ileocecal junction) and 2) bacterial beta-glucuronidase and beta-glucosidase activities in the intestinal contents and feces of broiler chickens. Three dietary treatments were randomly assigned to three groups of chicks, i.e., basal diet only (control group), basal diet + 0.1% dried culture of Lactobacillus acidophilus, and basal diet + 0.1% dried culture of a mixture of 12 Lactobacillus strains. The results showed that supplementation of the adherent Lactobacillus cultures to chickens, either as a single strain of L. acidophilus or as a mixture of 12 Lactobacillus strains, increased significantly (P < 0.05) the levels of amylase in the small intestine. However, the proteolytic and lipolytic activities in the small intestine were not affected by addition of either of the adherent Lactobacillus cultures. Addition of either L. acidophilus or a mixture of 12 Lactobacillus strains was also found to reduce significantly (P < 0.05) the intestinal and fecal beta-glucuronidase and fecal beta-glucosidase but not the intestinal beta-glucosidase at 40 d of feeding.

Amylases↗

PubMed2000

A comparison of commonly used anti-emetics for the prevention of emetic sequelae after a major gynaecological surgery.

STUDY DESIGN: Prospective, randomized, double-blind, placebo-controlled study involving one hundred ASA I-II patients undergoing major gynaecological surgery. OBJECTIVE: To study anti-emetic efficacy of intravenous (IV) ondansetron (4 mg), droperidol (2.5 mg), metoclopramide (10 mg), and placebo. PATIENTS AND METHODS: 100ASA physical status I-II undergoing major gynaecological surgery were randomized to receive intravenously (IV), one of the four test drugs 10 minutes before the end of anaesthesia. The incidence of postoperative nausea and vomiting following a standard anaesthetic technique was assessed. RESULTS: A significantly large number of patients who received ondansetron (88%) and droperidol (72%) were free of emetic sequelae when compared to placebo (41%); p < 0.05 (power of this observation is approximately 80% at the given significance level). Metoclopramide was ineffective. Patients given droperidol were significantly more sedated than those receiving ondansetron; p < 0.05. This is not surprising, as the dose of droperidol used in this study was higher than that currently recommended because we found lower doses to be ineffective in controlling nausea and vomiting in this group of patients. CONCLUSION: It was concluded that, of the drugs studied ondansetron is the best choice for anti-emetic prophylaxis after major gynaecological surgery.

Adult↗

PubMed1999

The role of monocytes and natural killer cells in mediating antibody-dependent lysis of colorectal tumour cells.

Monocytes and natural killer (NK) cells are known to be important effector cell populations in mediating antibody-dependent cell-mediated cytotoxicity (ADCC). Purified monocyte and NK effector cell populations, from normal and colorectal cancer (CRC) patients, together with a number of murine (17-1A and 323/A3) and their chimaeric (c17-1A) or humanised (3622W94) equivalents, and chimaeric (c) SF25 were compared for their ability to mediate ADCC of colorectal tumour cells. The chimaeric and humanised antibodies were significantly better at mediating tumour lysis than their murine equivalents with all-effector populations. When effector cells from CRC patients were used the cSF25 antibody was significantly better than 3622W94 (P < 0.02) which, in turn, was significantly better than c17-1A (P < 0.03). Depletion of NK cells produced a decrease in specific tumour lysis with all antibodies. In addition a higher rate of NK cell death was observed in CRC patients during the assay than in normal controls. The chimaeric and humanised antibodies stained a similar percentage of the HT-29 target cells (>80%), but 3622W94 bound to significantly more cells from primary tumour biopsies than cSF-25 (P = 0.001). Together, the results suggest that NK cells are the most important effector cell type mediating ADCC in vitro, that there is some impairment of NK function in CRC patients, and that cSF25 is the most potent antibody. For use in vivo the anti-Ep-CAM antibody 3622W94 would appear to be the most suitable reagent for further study.

Adenocarcinoma↗