Biomedical subjects

M R Amin

Publications and source records attributed to M R Amin.

At least 19 recordsLinked to original sources

PubMed2005

SR 141716A differentially attenuates the behavioral effects of delta9-THC in rhesus monkeys.

The prototypic cannabinoid CB1 antagonist SR 141716A is one important pharmacologic tool for examining CB1 receptors that mediate the behavioral and physiologic effects of delta9-tetrahydrocannabinol (delta9-THC). This study examined the effects of SR 141716A on the rate-decreasing, hypothermic and discriminative stimulus effects of delta9-THC in rhesus monkeys. In monkeys (n=4) responding under a multiple fixed ratio (FR-10:FR-10) schedule of food presentation and stimulus-shock termination, the potency of i.m. delta9-THC to decrease responding in the food component (ED50=0.64 mg/kg) was threefold greater than its potency in the stimulus-shock termination component (ED50=2.14 mg/kg). In the same monkeys, hypothermia was induced by delta9-THC at a dose (e.g. 0.32 mg/kg) that did not alter responding in either schedule component; the maximum decrease was 2.1 degrees C at a dose of 3.2 mg/kg. A dose of 0.32 mg/kg of SR 141716A, significantly attenuated delta9-THC-induced hypothermia without attenuating the rate-decreasing effects of delta9-THC in either component of the multiple schedule. The largest dose of i.m. SR 141716A that was studied, 1.0 mg/kg, significantly decreased rectal temperature and responding in the food component but did not significantly decrease responding in the stimulus-shock termination component of the multiple schedule. In a separate group of monkeys (n=3) that discriminated i.v. delta9-THC (0.1 mg/kg) while responding under an FR-5 schedule of stimulus-shock termination, SR 141716A (0.32 and 1 mg/kg) significantly increased the ED50 of the delta9-THC by 2.3- and 3.7-fold, respectively. Collectively, these results demonstrate that the behavioral effects of delta9-THC are not equally attenuated by SR 141716A.

Animals↗

PubMed2004

Thyrohyoid approach to cidofovir injection: a case study.

Various techniques for injection into the larynx have been well described, including transoral injection with indirect laryngoscopy or direct laryngoscopy and transcutaneous injection through the thyroid cartilage or cricothyroid membrane. We describe a case not amenable to these techniques, in which entry through the thyrohyoid membrane for injection of cidofovir was successfully performed with a thyrohyoid approach. This technique is described, and comparisons are made with currently available techniques.

Antineoplastic Agents↗

PubMed2003

A retrospective study on genito urinary Rhabdomyosarcoma.

A retrospective study was carried out on Genitourinary Rhabdomyosarcoma in the Department of Paediatric Surgery of Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh during the period January 1990 to December 1999. Total thirteen patients were treated during this period, age ranging from 1 month to 12 years. Eight patients were male and five were female (M: F = 1.6: 1). Diagnosis was made by history, thorough physical examination, digital rectal examination, ultrasonography, intravenous urography, CT scan and biopsy. All the patients were treated with chemoradiation theraphy as a first line of management and surgical excision was done for local residual tumours. Eight children (61.5%) were asymptomatic after completion of chemo-radiation therapy. Three (23.07%) patients discontinued the chemo-radiation schedule. Residual mass was present in one (7.7%) case for which partial cystectomy was done and the patient died in the 5th post operative day. Another patient (7.7%) who had pulmonary metastasis at the time of diagnosis, died during chemo-radiation therapy.

Child↗

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↗

PubMed2002

Thin layer chromatographical detection of tyrosine produced from L-[U-(14)C]phenylalanine by ruminal microbes.

Thin layer chromatographical detection of tyrosine (Tyr) synthesized from L-[U-(14)C]phenylalanine (Phe) (1 mM) by rumen bacteria (B) and protozoa (P) collected from fistulated Japanese Goat was carried out. About 16 and 12% of the added Phe was converted to Tyr by B and P, respectively. Large amount of radioactivity in ether fractions indicated an abundant production of aromatic acids from Phe. Small amount of radioactivity found in CO(2) fractions implied an occurrence of considerable decarboxylation reaction(s) by rumen bacteria and protozoa.

Animals↗

PubMed2001

Predicting outcome in pediatric coin ingestion.

OBJECTIVE: To determine the relationship between coin size, coin location, patient age, and patient weight and likelihood of coin passage through the esophagus following pediatric coin ingestion. A secondary objective is to test the hypothesis that coin denomination can be determined based on radiographic appearance. METHODS: A retrospective review was performed of all children seen and evaluated for coin ingestion at a single institution over a 25-month period. Outcome measures included the number of coins that were retained in the esophagus, and the number that passed. Various factors were assessed for their predictive value in judging outcome in coin ingestion cases. RESULTS: Nineteen percent of patients (15/79) in the study passed their ingested coins. Coin denomination could be accurately determined on every patient that had a standard AP or lateral X-ray film. These findings were marked when compared with the lack of reliability of history in determining coin denomination. Patients who passed coins were as a group older (4.6 vs. 3.2 year, P=0.04), but did not differ significantly by weight (19.5 vs. 15.4 kg, P=0.07) from those that retained the coins. Coins located at the gastroesophageal junction had a significantly higher passage rate than coins located elsewhere in the esophagus (89 vs. 8.2%, P<0.01). Coin size was not predictive of coin passage (P=0.7 by chi(2)). CONCLUSIONS: Radiographic assessment of coin denomination is reliable, but in this study could not be used to predict coin passage. Patient age and coin location at the gastroesophageal junction, however, do correlate with this event.

Child↗

PubMed2001

Self-consistent linear analysis of slow cyclotron and Cherenkov instabilities.

Slow cyclotron and Cherenkov instabilities are analyzed self-consistently for unbounded and cylindrical slow wave systems considering electron beam propagating along the direction of a guiding magnetic field. There are two electromagnetic modes present in the beam that are self-consistent solutions of Maxwell's equations. The wave equation in the beam becomes the Altar-Appelton-Hartree equation in the limit of zero beam velocity. For the unbounded system, the beam couples with the electromagnetic modes corresponding to the X and O modes, resulting in the slow cyclotron and Cherenkov instabilities, respectively. For the cylindrical system, axisymmetric electromagnetic modes in the beam are obtained by superposing the plane normal modes of the unbounded system. Since self-consistent boundary conditions require all field components, axisymmetric electromagnetic modes of cylindrical system are hybrid modes, which are classified as axisymmetric EH and HE modes. The slow cyclotron and Cherenkov instabilities occur for both axisymmetric modes. The temporal growth rate is calculated for each of the instabilities and compared.

Journal Article↗

PubMed2001

Cryopreservation of epididymal spermatozoa collected by needle biopsy from cynomolgus monkeys (Macaca fascicularis).

We have examined the motility, morphology, and cryopreservation of epididymal spermatozoa collected by needle biopsy from cynomolgus monkeys (Macaca fascicularis). At collection, epididymal sperm (23 x 10(6) +/- 4 x 10(6) sperm/sample; 611 x 10(6) +/- 116 x 10(6) sperm/ ml; n = 18) were alive (79 +/- 2%), motile (67 +/- 2%), and exhibited intact membranes (65 +/- 2%). Sperm maintained at room temperature in handling medium exhibited decreased motility over time, but head-to-head agglutination was limited. Tris egg-yolk extender containing 6% glycerol and dimethylsulfoxide (DMSO) did not significantly affect functional morphology, whereas extender containing propanediol significantly reduced motility, survival, and membrane integrity. Cryostorage reduced all measures of functional morphology independent of cryoprotectant. Post-thaw motility was superior for glycerol and DMSO compared to propanediol. Variation in glycerol concentration (4, 6, and 8%) produced equivocal effects on sperm functional morphology post-thaw. Needle biopsy may be a useful technique for laboratory and field-based collection of spermatozoa from nonhuman primates.

Animals↗

PubMed2001

Suppression of tumourigenicity, and induction of differentiation of the canine mammary tumour cell line MCM-B2 by sodium phenylacetate.

The authors evaluated the cell growth inhibition, reduction of tumourigenicity, and differentiation-inducing effects of sodium phenylacetate (NaPA) on a canine mammary tumour cell line. Treatment of the canine mammary tumour cell line (MCM-B2) with NaPA lead to the arrest of cell growth. Sodium phenylacetate induced changes in the cells to non-malignant characteristics, as indicated by a reduction of colony formation in semi-solid agar and a decrease in tumour formation in athymic mice. Moreover, NaPA induced morphological changes from a spindle-shaped to an epithelial-like appearance, and significant accumulation of lipid droplets in the cytoplasm. Immunohistochemically, these treated cells reacted clearly with the antibody for keratin/cytokeratin. Sodium phenylacetate treatment increased the expression of the milk-specific genes alpha-lactalbumin and beta-casein. The results of this study warrant an evaluation of NaPA in a clinical trial to establish its possible value as adjunctive treatment of malignant canine mammary tumours.

Animals↗

PubMed2001

Diagnostic laryngeal electromyography: The Wake Forest experience 1995-1999.

BACKGROUND: Laryngeal electromyography (LEMG) is a valuable diagnostic/prognostic test for patients with suspected laryngeal neuromuscular disorders. OBJECTIVE: To report our experience with diagnostic LEMG at the Center for Voice Disorders of Wake Forest University and to evaluate the impact of LEMG on clinical management. METHODS: Retrospective chart review of 415 patients who underwent diagnostic LEMG over a 5-year period (1995-1999). RESULTS: Of 415 studies, 83% (346 of 415) were abnormal, indicating a neuropathic process. LEMG results altered the diagnostic evaluation (eg, the type of radiographic imaging) in 11% (46 of 415) of the patients. Unexpected LEMG findings (eg, contralateral neuropathy) were found in 26% (107 of 415) of the patients, and LEMG results differentiated vocal fold paralysis from fixation in 12% (49 of 415). Finally, LEMG results altered the clinical management (eg, changed the timing and/or type of surgical procedure) in 40% (166 of 415) of the patients. CONCLUSIONS: LEMG is a valuable diagnostic test that aids the clinician in the diagnosis and management of laryngeal neuromuscular disorders.

Adult↗

PubMed2001

Proton pump inhibitor resistance in the treatment of laryngopharyngeal reflux.

OBJECTIVE: To describe the occurrence of relative proton pump inhibitor (PPI) drug resistance in the treatment of laryngopharyngeal reflux (LPR). STUDY DESIGN AND SETTING: A retrospective review was performed for 1053 consecutive adults undergoing double-probe (simultaneous esophageal and pharyngeal) pH testing in our laboratory. Two hundred five patients who had pH studies performed while taking at least a daily dose of PPI therapy were identified; 167 qualified for further analysis. The pH data was reviewed for the presence of abnormalities in either esophageal or pharyngeal acid exposure to evaluate drug efficacy. RESULTS: Forty-four percent (74/167) of the study patients demonstrated abnormal levels of acid exposure. Results were further analyzed to compare failure rates based on different dosage regimens. Patients on once daily doses of PPI failed at a rate of 56%, with lower failure rates for higher-dose regimens. CONCLUSIONS: A significant number of LPR patients on PPI therapy demonstrate relative drug resistance.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2001

Endoscopic arytenoid repositioning for unilateral arytenoid fixation.

OBJECTIVES: To describe a new endoscopic technique for medialization of the laterally fixed arytenoid. The surgical technique, endoscopic arytenoid repositioning, is described, and the results of a series of cases are discussed. STUDY DESIGN: Retrospective chart review. METHODS: Eight patients underwent the procedure. Six patients were available for long-term follow-up. Preoperative and postoperative voice ratings were compared to evaluate the success of the procedure. Follow-up ranged from 3 to 64 months (mean follow-up, 31.5 mo). RESULTS: Long-term follow-up in six cases revealed that 67% (4 of 6) patients had normal or near-normal postoperative voices and one patient experienced moderate improvement. The mean preoperative voice score was 4.24, and the mean postoperative voice score was 1.83 (range, 1-5). The difference was statistically significant (P < 0.001). CONCLUSIONS: Endoscopic arytenoid repositioning is a newly described procedure with a very specific indication: a unilateral, laterally fixed arytenoid complex resulting in a severely dysphonic voice. Though technically demanding, this procedure provides a promising option for medialization of the posterior glottis in a scarred larynx.

Adult↗

PubMed2001

Hemicricoidectomy for voice rehabilitation following hemilaryngectomy with ipsilateral arytenoid removal.

The purpose of this article is to describe an approach to reconstruction of the larynx after vertical partial laryngectomy with removal of the ipsilateral arytenoid cartilage. This method addresses the problem of postoperative posterior glottal incompetence (aphonia with or without aspiration). The technique involves resection of the ipsilateral half of the cricoid cartilage, use of an inferiorly based strap muscle flap for vocal fold reconstruction, and placement of a customized stent. This technique may be used at the time of the primary cancer extirpation or as a secondary rehabilitative procedure. Generally, patients who have undergone this procedure have had minimal postoperative breathiness with good phonatory and airway function. We recommend this reconstructive technique for patients with large posterior defects following hemilaryngectomy.

Adult↗

PubMed2000

Preliminary individual adjuvant therapy for gliomas based on the results of molecular biological analyses for drug-resistance genes.

New adjuvant therapy individualized by the results of reverse transcription-polymerase chain reaction (RT-PCR) for drug-resistance genes has been used to treat malignant gliomas. Protocol studies for malignant gliomas were not so encouraging in their therapeutic results because of heterogeneity and the various drug-sensitivities of the tumors. Individualization of glioma therapy is recommended. Drug-resistance genes messenger ribonucleic acid (mRNA) expressions were investigated in drug-resistant human glioma cell lines derived from U87MG and 46 frozen samples of retrospectively examined neuroepithelial tumors (12 low grade neuroepithelial tumors, 16 Grade III gliomas, 11 glioblastomas, and 7 other malignant neuroepithelial tumors such as medulloblastomas and primitive neuroectodermal tumors) by RT-PCR with the specific primers for O6-methylguanine DNA methyltransferase (MGMT), multidrug-resistance gene 1 (MDR1), multidrug-resistance-associated protein (MRP), and glutathione-S-transferase-pi (GST-pi). Thirty-seven preliminary individual adjuvant therapies (IAT) based on RT-PCR results, mainly in MGMT expression, were performed on 30 consecutive patients with neuroepithelial tumors. In the retrospectively examined series, the initial response to 1-(4-amino-2-methyl-5-pyrimidynyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) was correlated most significantly to the MGMT mRNA expression among 11 independent prognostic factors (p = 0.0037) in multivariate logistic regression analysis. In the preliminary IAT, 17 of 32 evaluable therapies had a partial or complete response (53.1% response rate). Our IAT based on RT-PCR seemed to be more effective than conventional therapies for malignant gliomas.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Prevalence of reflux in 113 consecutive patients with laryngeal and voice disorders.

OBJECTIVES: The goal was to estimate the prevalence of laryngopharyngeal reflux (LPR) in patients with laryngeal and voice disorders. STUDY DESIGN AND SETTING: This was a prospective study of 113 unselected, new patients with laryngeal and voice disorders. Patients completed an extensive medical history form including a reflux symptom profile. A comprehensive otolaryngologic examination was performed with photographic transnasal fiberoptic laryngoscopy. Patients with both symptoms and findings of LPR (78/133, 69%) underwent ambulatory 24-hour double-probe pH monitoring. RESULTS: Seventy-three percent (57/78) of patients undergoing pH testing had abnormal studies. Thus 50% (57/113) of the entire the study population had pH-documented reflux. Of the diagnostic sub-groups studied, the highest incidence of reflux was found in patients with vocal cord neoplastic lesions (88%) and patients with muscle tension dysphonias (70%). LPR was infrequently found in patients with neuromuscular disorders. CONCLUSION: LPR occurs in at least 50% of all patients at our center with laryngeal and voice disorders at presentation.

Adult↗

PubMed2000

A comparative study of MIB-1 staining indices of gliomas measured by NIH Image analysis program and conventional manual cell counting method.

To evaluate the NIH Image measured MIB-1 staining index (SI) as a useful tool for the determination of proliferative activity of gliomas, MIB-1 immunohistochemistry was performed on paraffin sections to estimate the proliferative activity of 50 gliomas. Five to eight RGB images at 200 magnifications were acquired per sample in a Macintosh computer using a RD-175 digital camera and Adope Photoshop program, followed by conversion of the RGB image to B (blue subtracted) and R (red subtracted) images and finally automatic cell counting of more than 1000 cells per sample by the NIH Image analysis program. The mean MIB-1 staining indices by both NIH count and visually assessed (manual) count respectively were 12.7% +/- 9.9% (mean +/- standard deviation) and 12.6% +/- 9.9% in all gliomas (n = 50), 2.9% +/- 0.6% and 2.3% +/- 0.6% in grade I and II astrocytomas (n = 9), 10.7% +/- 8.9% and 11.1% +/- 9.0% in grade III gliomas (n = 17), 16.1% +/- 9.1% and 16.3% +/- 9.1% in glioblastoma multiformes (n = 20), 26.0% +/- 4.9% and 24.5% +/- 2.6% in other glial tumors (n = 4). These paired values were assumed to be identical, since the p value obtained by paired t-test in all gliomas was 0.905. We conclude that the MIB-1 staining index measured by NIH Image is reliable and universal.

Antigens, Nuclear↗

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↗

PubMed1999

Straight midline mandibulotomy revisited.

OBJECTIVE: Describe recent experience with a simplified modification of the traditional mandibulotomy approach. STUDY DESIGN: Retrospective chart review. METHODS: Charts were reviewed retrospectively for 17 consecutive patients who underwent this approach over a 3-year period as a part of treatment for oral and oropharyngeal malignancies. RESULTS: No cases of bony nonunion, plate exposure, or other complications related to the mandibulotomy occurred in the postoperative phase. CONCLUSIONS: The modified straight midline mandibulotomy approach is simple and provides safe access for the treatment of oral and oropharyngeal tumors while minimizing postoperative morbidity.

Adult↗