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Biomedical subjects

N Mohammed

Publications and source records attributed to N Mohammed.

At least 19 recordsLinked to original sources
PubMed2006

A nurse-/pharmacy-led capecitabine clinic for colorectal cancer: results of a prospective audit and retrospective survey of patient experiences.

Oral chemotherapy agents provide patients with choice and home-based therapy but demand greater emphasis on patient support and education to minimise toxicities. To meet this demand, a nurse-/pharmacy-led clinic was established at the Beatson Oncology Centre in 2003 for the provision of oral capecitabine to metastatic colorectal cancer patients to provide a controlled and supportive environment. We conducted a prospective audit of 52 patients attending the clinic from March 2003 to June 2004 and a retrospective survey of patient experiences to assess clinic effectiveness. Of 52 patients, 79% completed at least 3 cycles of treatment (mean 3.5). Capecitabine was well tolerated. The dose was reduced on at least one occasion in 15 (29%) patients and 17 (30%) patients experienced at least one delay. Patient satisfaction, indicated by questionnaire responses (n=27), was high. Most patients (> or =85%) thought that the service provision was useful and well organised. The results indicate that a nurse-/pharmacy-led clinic for the provision of home-based oral capecitabine is safe, effective and acceptable to most patients. The success of this clinic can provide a model for use in other centres and in other types of cancer, such as breast cancer, where oral chemotherapy is a treatment option.

Administration, Oral↗
PubMed2004

Inhibition of ruminal microbial methane production by beta-cyclodextrin iodopropane, malate and their combination in vitro.

The objective of this study was to evaluate the effects of different concentrations of l-malate (0, 5, 10 and 20 mm), 2-iodopropane-beta-cyclodextrin complex (CD-IP) (0, 0.1, 0.2 and 0.4 mm) and a combination of malate (10 and 20 mm) plus CD-IP (0.2 and 0.4 mm) on methane production from corn starch. Ruminal fluid was collected from dairy cows, mixed with phosphate buffer (1 : 2) and incubated (30 ml) anaerobically at 38 degrees C for 6 h with or without additives. Fermentation of corn starch in the presence of malate resulted in an increase (p < 0.05) in pH of the medium, total volatile fatty acid (VFA), total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were unchanged. Methane production was decreased (p < 0.05) (15.5 to 20.4%). Addition of CD-IP in corn starch resulted in an increase (p < 0.05) in total VFA and molar proportion of propionate. Acetate, pH and ammonia-N concentration of the medium were decreased (p < 0.05). Total gas production was unchanged. Methane production was decreased (p < 0.05) (25.2 to 97.1%) and hydrogen production was increased (p < 0.05). Addition of l-malate to CD-IP resulted in an increase (p < 0.05) in total VFA, total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were decreased (p < 0.05). No effects were observed on medium pH. Methane production was decreased (p < 0.05) (49.5 to 97.1%). Hydrogen production was also decreased (p < 0.05) (54.5 to 64.1%) compared with those of CD-IP alone. Therefore, these additives may be used as supplements to inhibit methane production as well as to improve rumen fermentation and animal performance.

Animals↗
PubMed2004

Phylogenetic analysis of methyl coenzyme-M reductase detected from the bovine rumen.

AIMS: The object of the present study is isolation of methyl coenzyme-M reductase (MCR) genes (mcrA) from the bovine rumen fluid and determination of phylogenetical placements of the genes to investigate mechanisms of methanogenesis in the rumen from a point of view of mcrA genes. METHODS: Genes for methanogen-specific MCR were isolated from the bovine rumen by PCR amplification. The deduced amino acid sequences were fitted to the alignments of mcrA gene products from the referred sequences. SIGNIFICANCE AND IMPACT OF THE STUDY: Although the deduced amino acid sequences of mcrA genes, isolated from the bovine rumen in the present study, were close to that of Methanobrevibacter ruminantium, these amino acid sequences did not fall into known clusters of MCR. The findings suggest that methanogenesis in the rumen would be partially carried out by unknown methanogens.

Animals↗
PubMed2004

Comparison of the OptiMAL rapid antigen test with field microscopy for the detection of Plasmodium vivax and P. falciparum: considerations for the application of the rapid test in Afghanistan.

To establish the sensitivity and specificity of a batch of 'OptiMAL 48' rapid antigen tests procured by the World Health Organization in Afghanistan, a sample was tested, in parallel with routine, microscopical diagnosis, at basic health units (BHU) within Afghan refugee camps in Pakistan. The results of both methods of field diagnosis were compared with those of cross-checking microscopy at a reference laboratory, which were taken as the 'gold standard'. Out of 499 patients examined, 36% were diagnosed as malaria cases by field microscopy and 34% by the rapid test. For the OptiMAL 48 test, cross-checking of the corresponding smears at the reference laboratory gave a sensitivity of 79.3% and a specificity of 99.7% for Plasmodium falciparum and corresponding values of 86.1% and 98.7% for P. vivax infections. The performance of the field microscopy was better, with a sensitivity and specificity of 85.2% and 99.7% for P. falciparum, and 90.4% and 98.7% for P. vivax, respectively. These results show that the performance of OptiMAL 48 is adequate for acute- and post-emergency situations when the alternative is just clinical diagnosis. However, in the developing health system of Afghanistan, the main focus should be on the expansion of the existing network for microscopical diagnosis and quality control, to meet the needs of a stable situation. Rapid antigen tests are more suited to investigations of outbreaks in remote situations, where health services are deficient or absent.

Afghanistan↗
PubMed2004

Effect of Japanese horseradish oil on methane production and ruminal fermentation in vitro and in steers.

The effects of alpha-cyclodextrin-horseradish oil complex (CD-HR) on methane production and ruminal fermentation were studied in vitro and in steers. In the in vitro study, diluted ruminal fluid (30 mL) was incubated anaerobically at 38 degrees C for 6 h with or without CD-HR, using cornstarch as substrate. The CD-HR was added at various concentrations (0, 0.17, 0.85 and 1.7 g/L). Treatment affected neither the pH of the medium nor the number of protozoa. Total VFA increased in a linear manner (P = 0.02), and NH3-N decreased quadratically (P = 0.04) as the concentration of CD-HR increased from 0.17 g/L to 1.7 g/L. Molar proportions of acetate decreased in a linear manner (P = 0.03), and propionate increased linearly (P = 0.008) with increasing concentrations of CD-HR. Production of methane was inhibited up to 90%, whereas accumulation of dihydrogen was increased 36-fold by 1.7 g/L of CD-HR supplementation relative to controls. The effect of CD-HR on methane production, ruminal fermentation and microbes, and digestibility was further investigated in vivo using four Holstein steers in a crossover design. The CD-HR supplement was mixed into the concentrate portion of a (1.5:1) Sudangrass hay plus concentrate mixture that was fed twice daily to the steers. Ruminal samples were collected 0, 2, and 5 h after the morning feeding. No effects of CD-HR supplementation on ruminal pH (P = 0.63) or protozoal numbers (P = 0.44) were observed. Molar proportion of acetate was decreased (P = 0.04) and propionate was increased (P = 0.005) by CD-HR treatment. Molar proportion of butyrate was increased (P = 0.05) in CD-HR-supplemented steers. Ruminal NH3-N was decreased (P = 0.05) by treatment. Blood plasma glucose concentration was increased (P = 0.02) and urea-N was decreased (P = 0.04) with CD-HR supplementation. Daily DMI was decreased (P = 0.04), and apparent digestibility of DM (P = 0.13), NDF (P = 0.14), and CP tended (P = 0.14) to be increased by treatment. Methane production was decreased (P = 0.03) by 19%, and the number of methanogens was also decreased (P = 0.03). Although N retention (P = 0.11), total viable bacteria (P = 0.15), and sulfate-reducing bacteria (P = 0.17) were not significantly altered by treatment, tendencies for increases were noted with CD-HR supplementation. The number of cellulolytic (P = 0.38) and acetogenic bacteria (P = 0.32) remained unchanged by treatment. These results indicate that CD-HR supplementation can be used to decrease methane production in steers.

Animals↗
PubMed2004

Effects of a twin strain of saccharomyces cerevisiae live cells on mixed ruminal microorganism fermentation in vitro.

This experiment was designed to investigate the effects of different concentrations (0, 0.33, 0.66, 0.99, and 1.32 g/L) of a twin-strain of Saccharomyces cerevisiae live cells on in vitro mixed ruminal microorganism fermentation of corn starch, soluble potato starch, and sudangrass hay (60.5%, DM basis) plus concentrate mixture (39.5%, DM basis). Ruminal fluid was collected from two dairy cows, mixed with phosphate buffer (1:2), and incubated (30 mL) anaerobically at 38 degrees C for 6 and 24 h with or without yeast supplement, using 200 mg (DM basis) of each substrate. Medium pH, ammonia-N, and numbers of protozoa were unaffected (P = 0.38) by yeast cells in all substrates. Molar proportion of acetate was unchanged (P = 0.56) with cornstarch and soluble potato starch, but increased quadratically (P = 0.02) with hay plus concentrate by treatment. Addition of yeast cells caused a linear increase of total VFA (P = 0.008) in all substrates. Excluding the soluble potato starch, supplementation of S. cerevisiae resulted in a quadratic increase of propionate (P = 0.01), with a quadratic decrease (P = 0.04) of acetate:propionate. When soluble potato starch was used as a substrate, a linear increase (P = 0.006) of the molar proportion of propionate and a quadratic decrease (P = 0.007) in acetate:propionate was observed by treatment. Molar proportion of butyrate was unchanged (P = 0.35) with cornstarch and soluble potato starch, whereas it decreased linearly (P = 0.007) with hay plus concentrate by yeast cell supplementation. When cornstarch and soluble potato starch were used as a substrate, minor VFA were decreased (P = 0.05) by treatment. Accumulation of lactate was linearly decreased by treatment (P = 0.007) in all substrates. During incubation with hay plus concentrate, IVDMD was linearly increased (P = 0.006), whereas production of methane (linear; P = 0.02) and accumulation of hydrogen was decreased (quadratic; P = 0.005) by treatment after 24 h. These results showed that a twin strain of S. cerevisiae live cells stimulated in vitro mixed ruminal microorganism fermentation with decreased lactate, and a small decrease of methane and hydrogen with hay plus concentrate.

Ammonia↗
PubMed2003

Degradation of tryptophan and related indolic compounds by ruminal bacteria, protozoa and their mixture in vitro.

In vitro experiments were conducted to examine the degradation of d- and l-isomers of tryptophan (Trp) and 10 related indolic compounds by mixed rumen bacteria (B), protozoa (P) and a combination of the two (BP). The analyses were carried out by HPLC. d-Trp (1.0 mM) was not degraded by rumen microorganisms during the 24-h incubation period. The net degradation of 1 mM l-Trp was 46.5%, 8.7% and 80.0% by B, P and BP suspensions, respectively. Trp was degraded into indoleacetic acid, indolelactic acid and indole by rumen bacteria and protozoa, and into skatole, p-cresol and indolepropionic acid by rumen bacteria only. Of them, indoleacetic acid was the major product of Trp found in B (15.4%) and P (3.1%), and skatole in BP (43.2%). This is the first report of the production of indolelactic acid and p-cresol from Trp by rumen microbes. Starch, d-glucose, salinomycin and monensin inhibited the production of skatole and indole from Trp, and skatole from indoleacetic acid by rumen bacteria.

Animals↗
PubMed2003

Effect of sarsaponin on ruminal fermentation with particular reference to methane production in vitro.

This experiment was designed to investigate the effects of different concentrations (0, 1.2, 1.8, 2.4, and 3.2 g/L) of sarsaponin on ruminal microbial methane production using the substrates soluble potato starch, cornstarch, or hay plus concentrate (1.5:1). Ruminal fluid was collected from a dairy cow, mixed with phosphate buffer (1:2) and incubated (30 ml) anaerobically at 38 degrees C for 6 and 24 h with or without sarsaponin. Excluding the lower level of sarsaponin, pH of the medium was slightly decreased. Ammonia-N concentration and numbers of protozoa were decreased in a dose-dependent manner. Total volatile fatty acids and total gas production were increased. Molar proportion of acetate was decreased and propionate was increased with a corresponding decrease in acetate:propionate ratio. Hydrogen production was decreased. As the concentration of sarsaponin increased from 1.2 to 3.2 g/L, fermentation of soluble potato starch, cornstarch, or hay plus concentrate decreased methane production from 20 to 60% (6 h) and 17 to 50% (24 h), 21 to 58% (6 h) and 18 to 52% (24 h), and 23 to 53% (6 h) and 15 to 44% (24 h), respectively. Excluding the lower dose concentration (1.2 g/L) of sarsaponin, in vitro disappearance of dry matter of hay plus concentrate was decreased after 24 h. In conclusion, these results show that sarsaponin stimulated the mixed ruminal microorganism fermentation as well as to inhibit methane production in vitro.

Acetic Acid↗
PubMed2002

Aromatic amino acid biosynthesis and production of related compounds from p-hydroxyphenylpyruvic acid by rumen bacteria, protozoa and their mixture.

Aromatic amino acid biosynthesis and production of related compounds from p-hydroxyphenylpyruvic acid (HPY) by mixed rumen bacteria (B), protozoa (P), and their mixture (BP) in an in vitro system were quantitatively investigated. Microbial suspensions prepared from mature, fistulated goats fed Lucerne ( Medicago sativa) cubes and a concentrate mixture were anaerobically incubated at 39 degrees C for 12 h. Tyrosine (Tyr), phenylalanine (Phe), tryptophan (Trp) and other related compounds in both supernatants and hydrolyzates of all incubations were analyzed by HPLC. Large amounts of Tyr (27.0, 47.0 and 50.8% of disappeared HPY in B, P and BP, respectively) were produced from 1 mM HPY during a 12-h incubation period. The formation of Tyr in P was 1.8 and 1.6 times higher than those in B and BP, respectively. Appreciable amounts of Phe (3-12% of the disappeared HPY) and Trp (2-10% of the disappeared HPY) were also produced from HPY in B, P, and BP. Phe synthesis in B and P was almost similar but Trp synthesis in B was 1.8 times higher than that in P. The biosynthesis of both Phe and Trp from HPY in BP was higher than those in B plus P. A large amount of p-hydroxyphenylacetic acid (about 45% of the disappeared HPY) was produced from HPY in B which was 1.9 times higher than that in P. p-Hydroxybenzoic acid produced from HPY in P was 1.6 times higher than that in B. Considerable amounts of phenylpropionic acid, phenyllactic acid, and phenylpyruvic acid (2-6% of the disappeared HPY) were produced only in B.

Amino Acids, Aromatic↗
PubMed2001

Recombinant forms of tetanus toxin engineered for examining and exploiting neuronal trafficking pathways.

Tetanus toxin is a fascinating, multifunctional protein that binds to peripheral neurons, undergoes retrograde transport and trans-synaptic transfer to central inhibitory neurons where it blocks transmitter release, thereby, causing spastic paralysis. As a pre-requisite for exploiting its unique trafficking properties, a novel recombinant single chain was expressed at a high level in Escherichia coli as a soluble, easily purifiable protein. It could be activated with enterokinase to produce a dichain that matched native toxin in terms of proteolytic and neuroinhibitory activities, as well as induction of spastic paralysis in mice. Importantly, nicking was not essential for protease activity. Substitution of Glu(234) by Ala created a protease-deficient atoxic form, which blocked the neuroparalytic action of tetanus toxin in vitro, with equal potency to its heavy chain; but, the mutant proved >30-fold more potent in preventing tetanus in mice. This observation unveils differences between the intoxication processes resulting from retrograde transport of toxin in vivo and its local uptake into peripheral or central nerves in vitro, dispelling a popularly held belief that the heavy chain is the sole determinant for efficient trafficking. Thus, this innocuous mutant may be a useful vehicle, superior to the heavy chain, for drug delivery to central neurons.

Amino Acid Sequence↗
PubMed2001

Control of malaria in Pakistan by applying deltamethrin insecticide to cattle: a community-randomised trial.

BACKGROUND: The standard method of malaria control in south Asia, indoor spraying of houses with residual insecticide, is becoming prohibitively expensive to implement and new approaches are needed. Since the region's vector mosquitoes feed predominantly on domestic animals and only secondarily on human beings, to apply insecticide to surfaces of cattle instead might be more costeffective. We aimed to investigate whether domestic livestock treated with deltamethrin (applied by a sponging method) would prove toxic to mosquitoes and therefore aid in malaria control. METHODS: Six Afghan refugee settlements in Pakistan were randomly assigned to one of two groups. In one group livestock were treated with deltamethrin during the malaria transmission seasons of 1995 and 1997, whereas in the other group livestock were treated during the 1996 season. Malaria was monitored by passive case detection at village clinics and by cross-sectional surveillance. Mosquitoes were also monitored. FINDINGS: According to clinic records the incidence of malaria caused by Plasmodium falciparum decreased by 56% (95% CI 14-78%) and P vivax by 31% (5-50%) in livestock-treated villages. Cross-sectional surveys showed comparable decreases in parasite prevalence. The density and life expectancy of Anopheles stephensi and A culicifacies populations were reduced in treated villages. The efficacy of livestock treatment was similar to that of indoor spraying but campaign costs were 80% less. When applied in a highly endemic settlement, the incidence of falciparum malaria decreased from 280 episodes per 1000 person-years to nine episodes per 1000 person-years. INTERPRETATIONS: Insecticide treatment of livestock is a cost-effective and promising alternative for south Asia and other regions where primary vectors are zoophilic.

Animals↗
PubMed2000

Convenient method of threonine, methionine and their related amino compounds by high-performance liquid chromatography and its application to rumen fluid.

A high-performance liquid chromatographic procedure for the quantitative determination of cysteine (Cys), homocysteine (Hcys), methionine sulfoxide (MSO), methionine sulfone (MSO2), homoserine (Hser), glycine (Gly), threonine (Thr), 2-aminobutyric acid (2AB), methionine (Met), cystathionine (Cysta) and its application to rumen fluid are described. The samples containing Thr, Met and other related amino compounds were derivatized with 9-fluorenylmethyl chloroformate. The separation of compounds was accomplished with a methanol gradient in 25 mM sodium citrate buffer (obtaining pH 6.40 and 3.80 by addition of 25 mM citric acid). All derivatized compounds were separated on a Mightysil RP-18 GP (150x4.6 mm I.D., 5 microm particle size) column. All analytes were detected at 265 nm with UV detection. The limits of detection (microM) (S/N ratio, 3:1) and quantification (microM) (S/N ratio, 10:1) of Cys, Hcys, MSO, MSO2, Hser, Gly, Thr, 2AB, Met and Cysta were 0.50 and 1.68; 1.76 and 5.85; 0.85 and 2.88; 0.92 and 3.09; 1.04 and 3.52; 0.76 and 2.52; 0.65 and 2.18; 0.39 and 1.36; 0.31 and 1.03; 0.17 and 0.58, respectively. The recoveries of all compounds in rumen fluid were 97.93-102.3% in the within-day study and 94.52-98.69% on different day (6 days) studies. The average contents (microM) of Cys, Gly, Thr, 2AB, Met and Cysta were 1.72, 45.6, 20.0, 4.3, 2.11 and 3.42 before morning feeding. The concentration of Thr, 2AB and Cysta in rumen fluid tended to increase with time after feeding whereas Met showed the opposite tendency.

Animals↗
PubMed1999

Rescue of exocytosis in botulinum toxin A-poisoned chromaffin cells by expression of cleavage-resistant SNAP-25. Identification of the minimal essential C-terminal residues.

Botulinum neurotoxin (BoNT) types A and B selectively block exocytosis by cleavage of SNAP-25 and synaptobrevin, respectively; in humans, many months are required for full recovery from the resultant neuromuscular paralysis. To decipher the molecular basis for such prolonged poisoning, intoxication in adreno-chromaffin cells was monitored over 2 months. Exocytosis from BoNT/B-treated cells resumed after 56 days because of the appearance of intact synaptobrevin. However, inhibition continued in BoNT/A-treated cells, throughout the same interval, with a continued predominance of cleaved SNAP-25-(1-197) over the intact protein. When recovery from poisoning was attempted by transfection of the latter cells with the gene encoding full-length SNAP-25-(1-206), no restoration of exocytosis ensued even after 3 weeks. To ascertain if this failure was because of the persistence of the toxin's protease activity, the cells were transfected with BoNT/A-resistant SNAP-25 constructs; importantly, exocytosis was rescued. C-terminal truncation of the toxin-insensitive SNAP-25 revealed that residues 1-201, 1-202, 1-203 afforded a significant return of exocytosis, unlike shorter forms 1-197, -198, -199, or -200; accordingly, mutants M202A or L203A of full-length SNAP-25 rescued secretion. These findings give insights into the C-terminal functional domain of SNAP-25, demonstrate the longevity of BoNT/A protease, and provide the prospect of a therapy for botulism.

Animals↗
PubMed1999

Protein kinase B stimulates the translocation of GLUT4 but not GLUT1 or transferrin receptors in 3T3-L1 adipocytes by a pathway involving SNAP-23, synaptobrevin-2, and/or cellubrevin.

An interaction of SNAP-23 and syntaxin 4 on the plasma membrane with vesicle-associated synaptobrevin-2 and/or cellubrevin, known as SNAP (soluble N-ethyl-maleimide-sensitive factor attachment protein) receptors or SNAREs, has been proposed to provide the targeting and/or fusion apparatus for insulin-stimulated translocation of the GLUT4 isoform of glucose transporter to the plasma membrane. By microinjecting 3T3-L1 adipocytes with the Clostridium botulinum toxin B or E, which proteolyzed synaptobrevin-2/cellubrevin and SNAP-23, respectively, we investigated the role of these SNAREs in GLUT4, GLUT1, and transferrin receptor trafficking. As expected, insulin stimulated the translocation of GLUT4, GLUT1, and transferrin receptors to the plasma membrane. By contrast, a constitutively active protein kinase B (PKB-DD) only stimulated a translocation of GLUT4 and not GLUT1 or the transferrin receptor. The GLUT4 response to PKB-DD was abolished by toxins B or E, whereas the insulin-evoked translocation of GLUT4 was inhibited by approximately 65%. These toxins had no significant effect on insulin-stimulated transferrin receptor appearance at the cell surface. Thus, insulin appears to induce GLUT4 translocation via two distinct routes, only one of which involves SNAP-23 and synaptobrevin-2/cellubrevin, and can be mobilized by PKB-DD. The PKB-, SNAP-23-, and synaptobrevin-2/cellubrevin-independent GLUT4 translocation pathway may involve movement through recycling endosomes, together with GLUT1 and transferrin receptors.

3T3 Cells↗
PubMed1999

Production of tyrosine and other aromatic compounds from phenylalanine by rumen microorganisms.

Rumen contents from three fistulated Japanese native goats fed Lucerne hay cubes (Medicago sativa) and concentrate mixture were collected to prepare the suspensions of mixed rumen bacteria (B), mixed protozoa (P) and a combination of the two (BP). Microbial suspensions were anaerobically incubated at 39 degrees C for 12 h with or without 1 mM of L-phenylalanine (Phe). Phe, tyrosine (Tyr) and other related compounds in both supernatant and microbial hydrolysates of the incubations were analyzed by HPLC. Tyr can be produced from Phe not only by rumen bacteria but also by rumen protozoa. The production of Tyr during 12 h incubation in B (183.6 mumol/g MN) was 4.3 times higher than that in P. One of the intermediate products between Phe and Tyr seems to be p-hydroxyphenylacetic acid. The rate of the net degradation of Phe incubation in B (76.0 mumol/g MN/h) was 2.4 times higher than in P. In the case of all rumen microorganisms, degraded Phe was mainly (> 53%) converted into phenylacetic acid. The production of benzoic acid was higher in P than in B suspensions. Small amount of phenylpyruvic acid was produced from Phe by both rumen bacteria and protozoa, but phenylpropionic acid and phenyllactic acid were produced only by rumen bacteria.

Amino Acids↗