PubMed Health⌕ Search

Biomedical subjects

M R Amin

Publications and source records attributed to M R Amin.

26 records · Page 2Linked to original sources
PubMed1998

Quantitative determination of aromatic amino acids and related compounds in rumen fluid by high-performance liquid chromatography.

A rapid method for the quantitative determination of tyrosine (Tyr), phenylalanine (Phe), p-hydroxybenzoic acid (HBA), p-hydroxyphenylacetic acid (HPA), benzoic acid (BZA), p-hydroxyphenylpyruvic acid (HPY), phenylacetic acid (PAA), phenyllactic acid (PLA), tryptophan (Trp), indoleacetic acid (IAA), phenylpyruvic acid (PPY), phenylpropionic acid (PPA) and cinnamic acid (CNA) in goat rumen fluid was established by high-performance liquid chromatography (HPLC). The mobile phase used for isocratic elution was 50 mM sodium phosphate buffer (pH 6.5)-methanol (97:3, v/v). The flow-rate was 1.0 ml/min; column temperature 40 degrees C and compounds were monitored at 215 nm with a UV absorbance detector after injection of 10 microl of filtered rumen fluid. Analysis was completed within 40 min. The minimum detectable limits of quantification (microM) of these compounds were Tyr, 2; Phe, 3; HBA, 1; HPA, 2; BZA, 2; HPY, 8; PAA, 3; PLA, 4; Trp, 2; IAA, 2; PPY, 15; PPA, 8 and CNA, 4. Detectable levels of Tyr, Phe, HPA, BZA, HPY, PAA, PLA, Trp and PPA were found in the deproteinized rumen fluid of goat fed a haycube and concentrate mixture. PAA was the predominant compound before and after feeding. The concentrations of HPA, BZA, PAA, PLA and PPA in the goat rumen fluid increased after feeding, while the concentration of Tyr decreased. Phe, HPY and Trp were minor components at all times. PPY, IAA and CNA were not detected and HBA was not completely resolved in the goat rumen fluid.

Amino Acids↗
PubMed1997

State-dependent laryngomalacia.

We have observed 5 infants who demonstrate normal breathing when awake, but develop stridor while asleep. Flexible laryngoscopy in the awake state reveals either a normal larynx or redundancy of the aryepiglottic folds or arytenoid soft tissue without prolapse into the laryngeal inlet. When these children are sedated, however, the classic signs of laryngomalacia appear. Wet inspiratory stridor with concomitant supraglottic prolapse can be demonstrated by flexible videolaryngoscopy in this state. As these findings vary with level of consciousness, we have dubbed this condition "state-dependent" laryngomalacia. We believe the appearance and disappearance of classic laryngomalacia with changes in level of consciousness adds credence to the neurogenic theory of laryngomalacia.

Consciousness↗
PubMed1995

Rapid determination of phenylalanine and its related compounds in rumen fluid by high-performance liquid chromatography.

A rapid method for the determination of phenylalanine (Phe), tyrosine (Tyr), benzoic acid (BZA), phenylacetic acid (PAA), phenyllactic acid (PLA), phenylpyruvic acid (PPY), phenylpropionic acid (PPR), and cinnamic acid (CNM) in goat rumen fluid was established by high-performance liquid chromatography (HPLC). The mobile phase used for isocratic elution was methanol-sodium acetate buffer (pH 6.5) (8:92, v/v). The compounds were monitored at 220 nm with a UV detector. A 5-microliters portion of the filtrated rumen fluid was analyzed and the analysis was completed within 20 min. The minimum detectable limits (microM) of these compounds were: 12 for Phe, 3 for Tyr, 3 for BZA, 9 for PAA, 12 for PLA, 15 for PPY, 20 for PPR, and 8 for CNM. The average contents of Phe, BZA, PAA, PLA, and PPR in the rumen fluid of three goats were 15.4, 73.7, 615.9, 51.1, and 39.9 microM before morning feeding, 17.0, 123.7, 650.4, 208.2, and 502.4 microM at 3 h after feeding, and 18.4, 124.2, 510.0, 129.9, and 178.5 microM at 6 h after feeding, respectively. Of these compounds PAA was present at the highest concentration both before and after feeding. The content of PPR extremely increased especially at 3 h after feeding. The other three compounds, i.e. Tyr, PPY, and CNM, were not detected in goat rumen fluid.

Amino Acids↗
PubMedDate not supplied

Growth performance of Bangladeshi affluent school children (5-14 years).

A cross sectional anthropometric survey of 2045 healthy children (5-14 years) of affluent society of Dhaka City was done with the aim to compare their growth with the National Centre for Health Statistics (NCHS) standard. It was found that both weight and height of boys and girls of the studied children fall between 25th to 50th percentile of NCHS standard. In case of boys, body weight deviates below 25th percentile after 12 years whereas mean height is nearly parallel to 50th percentile up to 14 years. In case of girls, the pattern of growth is same except the fall below 25th percentile at the age of 8 and 9 years and the height remains above 25th percentile up to 12 years. It can be concluded that mean growth of affluent Bangladeshi school children is comparable to NCHS standard with minor variations.

Adolescent↗
PubMedDate not supplied

Vagal neuropathy after upper respiratory infection: a viral etiology?

PURPOSE: To describe a condition that occurs following an upper respiratory illness, which represents injury to various branches of the vagus nerve. Patients with this condition may present with breathy dysphonia, vocal fatigue, effortful phonation, odynophonia, cough, globus, and/or dysphagia, lasting long after resolution of the acute viral illness. The patterns of symptoms and findings in this condition are consistent with the hypothesis that viral infection causes or triggers vagal dysfunction. This so-called postviral vagal neuropathy (PVVN) appears to have similarities with other postviral neuropathic disorders, such as glossopharyngeal neuralgia and Bell's palsy. MATERIALS AND METHODS: Five patients were identified with PVVN. Each patient's chart was reviewed, and elements of the history were recorded. RESULTS: Each of the 5 patients showed different features of PVVN. CONCLUSIONS: Respiratory infection can trigger or cause vocal fold paresis, laryngopharyngeal reflux, and neuropathic pain.

Aged↗
PubMedDate not supplied

Rapid determination of lysine in biological samples by isocratic liquid chromatography.

A simple, rapid, and sensitive method was developed for detection and quantitation of lysine (Lys) in various biological samples by isocratic liquid chromatography (LC). Samples containing Lys and other amino acids were derivatized with 9-fluorenylmethyl chloroformate (FMOC-CI). The mobile phase used for isocratic elution was 50 mmol/L sodium acetate buffer (pH 4.20)-acetonitrile (43 + 57, v/v). Lys was detected with a UV detector at 265 nm. The derivatized Lys eluted from a LiChrospher 100 RP-18 (150 x 4.0 mm id) column at a retention time of 5.6 min. The limit of detection was 0.73 mumol/L (signal-to-noise [S/N] ratio, 3:1), and the limit of quantitation was 2.37 mumol/L (S/N ratio, 10:1). Lys recoveries from fortified biological samples were > 97.5%. Average Lys contents found in rumen fluid samples collected before the morning feeding and at 2.0, 4.0, and 6.0 h after feeding were 4.26, 3.34, 3.58, and 3.82 mumol/L, respectively. The hydrolysate of a sample of mixed rumen microorganisms collected before the morning feeding was determined to contain 1.372 mumol/mg microbial nitrogen in the form of Lys. The Lys concentrations of human plasma, goat plasma, human urine, and goat urine were 140.0, 102.0, 58.0, and 32.0 mumol/L, respectively.

Animals↗
PubMedDate not supplied

Determination of histidine and related compounds in rumen fluid by liquid chromatography.

A liquid chromatographic procedure was developed for quantitative determination of histidine (His), histidinol (HDL), histamine (HTM), urocanic acid (URA), imidazolepyruvic acid (ImPA), imidazoleacetic acid (ImAA), and imidazolelactic acid (ImLA) in rumen fluid. The method is based on direct injection analysis by UV absorbance detection at 220 nm. The separation was performed under 2 different chromatographic conditions on a LiChrospher 100 NH2 column. In the first chromatographic system, the mobile phase used for isocratic elution was 67 mM potassium phosphate buffer (monobasic and dibasic) pH 6.45-90% acetonitrile in water (21 + 79); in the second system, an acetonitrile gradient in 63 mM potassium phosphate buffer (monobasic) pH 3.0, obtained by addition of 60 mM phosphoric acid, was used. Analyses of both systems were completed within 32 and 25 min, respectively. The limits of detection of these compounds were (microM): His, 2.8; HDL, 3.7; HTM, 4.0; URA, 0.75; ImPA, 4.7; ImAA, 1.2; and ImLA, 1.3. Recovery of these compounds added to rumen fluid was 97.4-103.0% within a 1-day study and 95.4-99.0% on different day studies. Detectable levels of His were found in the deproteinized rumen fluid of goats, with average concentrations of 16.10, 10.43, 11.14, and 13.62 microM in the rumen fluid collected before the morning feeding and 2, 4, and 6 h after feeding, respectively. HDL, HTM, URA, ImPA, ImAA, and ImLA were not detected in the rumen fluid before and after feeding. Trp, Phe, and Tyr were also identified in the rumen fluid, with average concentrations of 8.25, 29.04, and 12.6 microM, respectively, before the morning feeding.

Animals↗