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Biomedical subjects

A A Ali

Publications and source records attributed to A A Ali.

At least 37 records · Page 2Linked to original sources
PubMed1999

Ventrally emigrating neural tube cells differentiate into vascular smooth muscle cells.

A multipotential cell population originating in the ventral part of the hindbrain neural tube, the ventrally emigrating neural tube cells (VENT cells), has recently been shown to migrate into the craniofacial mesenchyme. Because vascular smooth muscle cells develop from this mesenchyme, we sought to determine if the VENT cells contributed to their differentiation. VENT cells were tagged with replication-deficient retroviral vector with LacZ by microinjection into the lumen of the rostral hindbrain of chick embryos on day 2. Embryos were processed for the detection of LacZ positive cells on day 7. LacZ-positive cells were present in the wall of craniofacial arteries and veins. Immunostaining with the smooth muscle alpha-actin confirmed the labeled cells to be smooth muscle cells. It is concluded that some vascular smooth muscle cells differentiate from neural tube cells. the developmental and functional significance of which remains to be established.

Actins↗
PubMed1998

Ventral neural tube cells differentiate into craniofacial skeletal muscles.

Craniofacial skeletal muscle cells are believed to develop from mesoderm. A population of ventral neural tube cells has recently been shown to migrate out of the hindbrain and populate the craniofacial mesenchyme in chick embryos. Since skeletal muscle cells develop from this mesenchyme, we sought to determine if the emigrated neural tube cells contributed to their development. Ventral neural tube cells in the hindbrain of chick embryos were labeled on embryonic day 2 with replication-deficient retroviral vectors containing the gene LacZ, which provides a permanent marker for the progeny. On day 7 embryos were processed for the detection of labeled cells. Labeled cells were seen in craniofacial skeletal muscles. By using muscle-specific markers, the labeled cells were confirmed to be skeletal muscle cells. Thus, some muscle cells are derived from the ventral neural tube cells of the hindbrain.

Animals↗
PubMed1998

Urinary N-acetyl-beta-D-glucosaminidase in rheumatoid arthritis.

Excretion of urinary N-acetyl beta-D-glucosaminidase (NAG) and its isoenzyme patterns were studied in two groups of patients with rheumatoid arthritis (RA) and in normal control subjects. Urine samples were collected from 30 seropositive RA patients, 19 seronegative RA patients, and 15 normal healthy subjects. All the patients and normal subjects were assessed to have normal liver and kidney functions. A small portion of the urine sample was dialyzed against 0.01 M phosphate buffer, pH 7.0 and NAG activity was monitored. Mean +/- SD values of urinary NAG in seropositive RA patients, in seronegative RA patients and in normal healthy subjects were found to be 4.20 +/- 3.73 U/g creatinine, 2.96 +/- 2.11 U/gm creatinine, and 1.71 +/- 0.6 U/g creatinine, respectively. The mean urinary, NAG value in RA patients was found to be significantly higher (P < 0.05) in seropositive RA compared to the mean NAG value in normal healthy subjects and patients with seronegative RA when analyzed by one way ANOVA and Tukey-HSD test. The mean proportion of isoenzyme form B to isoenzyme form A in seropositive RA patients was also found to be significantly different (P < 0.05) from the mean proportion of these forms in normal healthy subjects and seronegative RA patients. There also appears to be a correlation between the concentration of urinary NAG and severity of the disease in seropositive RA.

Acetylglucosaminidase↗
PubMed1998

The effects of non-steroidal anti-inflammatory drugs on the disposition of methotrexate in patients with rheumatoid arthritis.

We have studied the pharmacokinetics of methotrexate in patients with rheumatoid arthritis concurrently taking the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, diclofenac, naproxen, indomethacin, and ibuprofen. The area under the curve, the total systemic clearance, the distribution volume, and the half-life of methotrexate in patients receiving concurrent NSAID therapy did not change significantly (at p < 0.05). Concurrent treatment with NSAIDs resulted in increased inter-patient variability of methotrexate concentration, possibly as a result of biochemical interactions; however, it does not appear clinically relevant. The data suggest that the NSAIDs do not significantly affect the disposition of methotrexate, contrary to some of the earlier reports.

Adolescent↗
PubMed1998

Fermentation of milk permeate by proteolytic bacteria for protease production.

Kinetics of cell growth and protease production by four proteolytic bacterial strains, namely, Bacillus subtilis EMCC 1020, Bacillus megaterium EMCC 1057, Serratia marcescens EMCC 1247, and Pseudomonas fluorescens EMCC 1221, in milk permeate, compared with other fermentation media, were studied. The pH values, lactose utilization, and biochemical oxygen demand (BOD) reduction in milk permeate also were investigated. The four strains were able to grow in milk permeate, and to produce considerable amounts of protease, reaching 289 (EMCC 1020), 252 (EMCC 1057), 263 (EMCC 1247), and 212 (EMCC 1221) U/mL after 30 h of fermentation. The growth and enzyme activity of the four strains were greater in milk permeate than those in other fermentation media. The protease-producing bacteria were able to utilize lactose in milk permeate with values ranging from 37.62 to 54.97% and to reduce the BOD of milk permeate by 50.59-63.65%. Milk permeate proved to be the best medium for enzyme production by all organisms examined.

Animals↗
PubMed1998

Emigration of neuroepithelial cells from the hindbrain neural tube in the chick embryo.

It is generally believed that after the emigration of neural crest, the neuroepithelial cells of the neural tube are committed to differentiate only as neurons and supporting cells of the central nervous system. Neural crest cells arise from the dorsal portion of the developing neural tube and contribute to the formation of the peripheral nervous system and a variety of non-neural structures. In contrast to this view we have recently shown, by focal application of the vital dye Dil in duck embryos, that an additional population of cells emigrates from the neural tube. By using an entirely different technique we confirm and extend these observations in the chick embryo. Replication-deficient retroviral vector LZ12 containing the gene LacZ was utilized to label the neural tube cells. The viral concentrate was microinjected into the lumen of the rostral hind-brain neural tube, considerably after the completion of emigration of neural crest cells. The labeled cells were monitored in whole mounts and histological sections. Initially, the labeled cells were restricted to the neuroepithelium of the hindbrain neural tube. Subsequently, they were seen in the neural tube and in the ganglion of the fifth cranial nerve (trigeminal ganglion). Later, they migrated beyond the trigeminal ganglion, i.e., into the mesenchyme of the first pharyngeal arch. Immunostaining with the neural crest cell marker, HNK-1, indicated that the emigrated neuroepithelial cells were HNK-1 negative. It is concluded that in the chick embryo some neuroepithelial cells emigrate at the site of attachment of the trigeminal nerve, migrate into the ganglion and then into the mesenchyme of the first arch. This cell population differs antigenically from the neural crest cells.

Animals↗
PubMed1998

The relationship between perlecan and dystroglycan and its implication in the formation of the neuromuscular junction.

Perlecan is a major heparan-sulfate proteoglycan (HSPG) within the basement membrane surrounding skeletal muscle fibers. The C-terminus of its core protein contains three globular domain modules which are also found in laminin and agrin, two proteins that bind to dystroglycan (DG, cranin) on the muscle surface with these modules. In this study, we examined whether perlecan can also bind to DG and is involved in signaling the formation of the neuromuscular junction (NMJ). By labeling cultured muscle cells with a polyclonal anti-perlecan antibody, this protein is found both within the extracellular matrix in a fibrillar network and at the cell surface in a punctate pattern. In Xenopus muscle cells, the cell-surface perlecan is precisely colocalized with DG. Both perlecan and DG are clustered at ACh receptor clusters induced by spinal neurons or by beads coated with HB-GAM, a heparin-binding growth factor. Blot overlay assays have shown that perlecan binds alpha-DG in a calcium and heparin-sensitive manner. Furthermore, perlecan is present in muscle lysate immunoprecipitated with an anti-DG antibody. Immunolabeling also showed colocalization between HB-GAM and perlecan and between HB-GAM and DG. These data suggest that perlecan is anchored to muscle surface via DG-dystrophin complex. Since DG is also a site of agrin binding, the neural agrin secreted by motoneurons during NMJ formation may compete with the pre-existing perlecan for cell surface binding. This competition may result in the presentation of perlecan-bound growth factors such as HB-GAM to effect synaptic induction.

Animals↗
PubMed1998

Methotrexate in rheumatoid arthritis: a 2 year experience at a university hospital in Pakistan.

In this study we report our two years experience of methotrexate (MTX) in the management of rheumatoid arthritis (RA) at the Aga Khan University Hospital, Karachi. We studied the clinical course of 124 RA patients. The mean age was 44 +/- 11 years (range 19-72) and mean duration of RA was 5 +/- 4 years (range 0.3-25). Female to male ratio was 10:2.4 (100F:24M). All of them were diagnosed according to the criteria set by American Rheumatism Association. The mean value of ESR was 60 +/- 30 (Range 3-128). Fifty one percent had severe disease (> 10 joints involved and evidence of erosions and deformities). Twenty-one patients had extra-articular manifestations. None of them had received MTX previously. Their kidney and liver functions were assessed to be normal. Patients were divided into two groups. One group (n = 92) received MTX (7.5-10 mg/week) as initial treatment, while the other group (n = 32) was given other disease modifying anti-rheumatic drugs (penicillamine, salazopyrin, gold, or chloroquine) followed by MTX. Assessment of the treatment outcome and development of any adverse reactions was carried out at 3-month interval over an average period of 1 year. Assessment of the treatment outcome in the group which received MTX as initial drug revealed the response to be excellent in 13%, good in 70%, fair in 11% and variable in 4%. In the group which received MTX as second-line of therapy, 59% of the patients had the response from good to excellent, while 25% of the patients exhibited poor to fair response. Regarding side-effects of MTX treatment, 57% exhibited none, while 35% had nausea and vomiting. Alopecia was the next common toxicity in these patients. Two individuals had abnormal liver function tests (value twice more than normal), while one developed lung fibrosis. MTX despite its adverse effects in some of the patients is still an effective, well tolerated and inexpensive disease modifying drug in RA.

Adult↗
PubMed1998

Modified Salter's innominate osteotomy.

Twenty paediatric patients with congenital dislocation of the hip were treated with a modification of the classic technique of Salter's osteotomy. Along with open reduction and femoral shortening osteotomy, the resected femoral segment, which measured 10-40 mm in width (mean 16 mm), was used to stabilize the Salter's osteotomy. The patients were aged between 2 and 9 years (mean 3.8 years). After a mean follow-up of 16 months (range 6-60 months) all patients had full bone healing and complete incorporation of femoral bone graft with the acetabulum. No patient had re-dislocation, subluxation or displacement of the graft.

Child↗
PubMed1998

Studies on Securigera securidacea (L.) Deg. et Dörfl. (Fabaceae) seeds, an antidiabetic Egyptian folk medicine.

A new cardenolide(-)-14-methoxy-rcanoside (1) was isolated from the aqueous extract of the seeds of Securigera securidacea (L.) Deg. et Dörfl. (Fabaceae) together with five new dihydrobenzofuran derivatives named securigran I-V (2-6). Kaempferol and astragalin were also isolated from the aqueous extract of the flowers. (-)-14-Methoxyhyrcanoside and the total aqueous extract of the seeds showed marked chronotropic activity. The total aqueous extract also showed a marked diuretic and severe hypokalemic effects on the K(+)-level in serum. The hypoglycemic effect of the seeds was also confirmed.

Animals↗
PubMed1997

Effect of Khat chewing on the bioavailability of ampicillin and amoxycillin.

The study examined the effect of Khat chewing on ampicillin and amoxycillin bioavailability following the administration of a 500 mg single dose of each antibiotic at different times relative to Khat chewing. Using a urinary excretion method the bioavailabilities of ampicillin and amoxycillin were determined in eight healthy adult male Yemeni volunteers. The extent and rate of ampicillin bioavailability were reduced significantly by Khat chewing except when administered 2 h after the Khat chewing session. However, the bioavailability of amoxycillin was only significantly reduced when the antibiotic was taken midway through the Khat chewing session. It was concluded that the two antibiotics, particularly ampicillin, should be taken 2 h after Khat chewing.

Adult↗
PubMed1996

Neonatal meningitis in northern Jordan.

A two-and-a-half year prospective study of neonatal meningitis in the two main referral hospitals in Northern Jordan was carried out to determine the clinical spectrum and particular characteristics of meningitis in the newborn. The 53 cases studied represented an incidence of 1.1 per 1000 live births. The commonest bacterial pathogen isolated was Klebsiella species (40 per cent) followed by Enterobacter (19 per cent). The mortality rate and neurological sequelae among surviving children were 32 and 39 per cent, respectively, with higher rates among preterm/low birth weight and early onset meningitis groups. Of the presenting clinical features, there was a highly positive association between two risk factors and outcome. A bulging anterior fontanelle was the only significant predictor of mortality (P = 0.009) and altered sensorium was the only predictive of post-meningitis sequelae (P = 0.016). The need to recognize that Klebsiella species is an increasingly important pathogen; cefotaxime or ceftazidime plus ampicillin are the most appropriate antibiotics to be used initially, and continuous surveillance thereafter have been stressed.

Anti-Bacterial Agents↗
PubMed1996

Hazard analysis and critical control point evaluation of school food programs in Bahrain.

Hazard analyses were conducted in six food preparation sites and 16 school canteens in the State of Bahrain. Sandwiches made with cheese, meat, eggs, liver, and beef burgers were prepared in small shops or a bakery outside schools. Foods were cooked between 4 and 5 A.M. Time-temperature exposure during cooking was adequate to kill vegetative microbes and their spores, but potential for recontamination existed from the hands of food workers, utensils, and cloths and sponges used for wiping. All foods were left at room temperature before they were transported in vans to schools where they were also kept at room temperature between 17 degrees C and 41 degrees C. Air temperature inside the canteens during this investigation was between 18.5 and 28 degrees C with a relative humidity of 65 to 70%. Hazard analyses, which included observation of operations inside school canteens and sites of food preparation, measuring temperatures, and interviewing workers and consumers (teachers, students) were carried out. Hazards were primarily associated with preparation of foods long before they were consumed, physical touching of products, and holding foods at room temperature after preparation. Holding foods at room temperature would have allowed germination of bacterial spores and multiplication of microbes. Reheating of foods was not practiced. Health promoters must be aware of these hazards and need to educate food workers, administrators, and the public on the methods of prevention.

Animals↗
PubMed1995

The role of heparin-binding growth-associated molecule (HB-GAM) in the postsynaptic induction in cultured muscle cells.

The heparan sulfate proteoglycan (HSPGs) is a components of the extracellular matrix of skeletal muscle that is concentrated at the neuromuscular junction (NMJ). Recent studies have suggested that HSPG, together with its bound peptide growth factors, plays important roles in autocrine or paracrine types of regulation of cell growth and differentiation. Heparin-binding growth-associated molecule (HB-GAM; also known as pleiotrophin, or p18) is a newly discovered HSPG-bound factor that is expressed at high levels in the developing CNS and PNS. In this study, we examined the role of this factor in NMJ development by examining its relationship to the formation of ACh receptor (AChR) clusters. Using an antibody against recombinant rat brain HB-GAM, we found that this protein is present prominently on the surface of cultured Xenopus myotomal muscle cells by immunocytochemistry. It is associated with HSPGs as evidenced by the fact that heparin and heparinase treatment greatly diminished the antibody labeling. HB-GAM is concentrated at preexisting AChR hot spots as well as at those induced by polystyrene beads. In addition, this molecule is also concentrated at AChR clusters induced by spinal cord neurons in nerve-muscle cocultures. To assess its function in synaptic induction, we applied recombinant HB-GAM-coated beads to cultured muscle cells to effect its focal presentation. Over 70% of these beads induced the formation of AChR clusters as shown by fluorescent alpha-bungarotoxin labeling. Furthermore, bath application of HB-GAM inhibited the nerve-induced formation of AChR clusters. Thus, HB-GAM is an endogenous muscle-derived factor that may be a component of the molecular mechanism in postsynaptic induction.

Animals↗
PubMed1994

Lactic acidosis and renal enlargement at diagnosis and relapse of acute lymphoblastic leukemia.

Bilateral renal enlargement was noted on ultrasonography during an extensive renal evaluation for severe hypokalemic metabolic acidosis with an increased anion gap in a 12-year-old Hispanic boy who had normal results of a physical examination and complete blood count. The patient was found to have acute lymphoblastic leukemia. Resolution of the lactic acidosis and bilateral renal enlargement occurred with initiation of chemotherapy and recurred with each subsequent relapse.

Acidosis, Lactic↗
PubMed1993

Retinoblastoma gene product-associated proteins in human colon cancer cell lines.

The expression of cellular proteins that associate with the human retinoblastoma (RB1) gene protein was examined in three colorectal carcinoma cell lines (SW480, SW403, DiFi) by immunoprecipitation analysis, using the mouse monoclonal antibody (RB-MAb-1) directed against the RB1 gene product (RB). The potential of RB-MAb-1 to detect RB-associated proteins by immunoprecipitation analysis was confirmed using three control cell lines (WI-38, J82, T24) known to express RB and/or RB-associated proteins. In all colon cancer cell lines tested, multiple RB-associated protein (RAP) bands were found with molecular weights of 30-50 kDa. Because involvement of the RB1 gene in colorectal tumorigenesis appears to differ from its role in other cancer types (wherein RB1 is lost or inactivated), it will be important to characterize the role of RAPs in RB growth regulatory mechanisms of colonic epithelial cells.

Adenocarcinoma↗