Biomedical subjects

A Mohamed

Publications and source records attributed to A Mohamed.

At least 55 records · Page 3Linked to original sources

PubMed1999

Hippocampal chemical anatomy in pediatric and adolescent patients with hippocampal or extrahippocampal epilepsy.

We determined whether age or seizure types were associated with hippocampal neuron loss, mossy fiber (MF) and GABAergic synaptic reorganizations or postsynaptic receptor densities. Children and adolescents were grouped into: (1) nonhippocampal sclerosis (non-HS; n = 11) and (2) hippocampal sclerosis (HS; n = 11). The most important results showed that: (1) regardless of the etiology of the seizures, there were greater cell losses in Ammon's horn with older ages in years; in the non-HS group, cell losses were greater with the older ages or with longer epilepsy durations; however, in the HS patients, the cell losses were not related to the patients' ages or epilepsy durations; (2) in both HS and non-HS, CA1 had greater cell losses than CA4; (3) in HS, CA1 and CA4 had greater cell losses than those in non-HS; (4) in non-HS, MF sprouting was greater with ages or with longer epilepsy durations; by contrast, in HS, MF sprouting was not related to the patients' age or epilepsy duration; (5) densities for AMPA GluR1, GABA-Abeta and for GABA axonal terminals were positively increased with age. These findings support the hypothesis that hippocampal cell losses and aberrant synaptic reorganizations are greater in the hippocampi of adolescents than in children, even for non-HS pathologies.

Adolescent↗

PubMed1999

Prevalence of chronic inflammatory demyelinating polyneuropathy in New South Wales, Australia.

A prevalence study of chronic inflammatory demyelinating polyneuropathy (CIDP) was performed in New South Wales (NSW), Australia, with a prevalence day of August 6, 1996, which coincided with a national census. The population of NSW was 5,995,544, and the crude prevalence of CIDP was 1.9 per 100,000 population. It was higher in male patients than in female patients, and the age-specific prevalence reached a maximum of 6.7 per 100,000 population in the 70- to 79-year-old age group. The prevalence in the city of Newcastle, with a population of 448,663, was 2.0 per 100,000 population and is representative of the whole of NSW. The estimated crude annual incidence was 0.15 per 100,000 population. The mean age of onset was 47.6 years (median, 53.5 years), 51% of patients had a relapsing-remitting course, the mean duration on prevalence day was 7.1 years (median, 5 years), and 87% of patients were able to walk without walking aids or other assistance.

Adolescent↗

PubMed1998

Conduction block in vasculitic neuropathy.

Vasculitis involving peripheral nerves usually presents as an acute asymmetrical axonal neuropathy. We report a 67-year-old man with a symmetrical subacute neuropathy in which nerve conduction studies showed prominent conduction block, a finding indicative of demyelination. Sural nerve biopsy showed a vasculitic neuropathy with invasion of blood vessel walls by inflammatory cells and a mixture of nerve fiber loss and demyelination. The demyelination in this case was presumably a consequence of subinfarctive nerve ischemia.

Action Potentials↗

PubMed1997

Growth of human nondiploid primary prostate tumor epithelial cells in vitro.

Research into molecular and cellular defects underlying prostate cancer would be advanced by in vitro models of prostate tumor cells representing patient tumors. We have propagated, in serum-free medium, epithelial cell cultures derived from nondiploid prostate tumors and normal human prostate. The serial passage tumor cells exhibited nondiploid karyotype and transformed phenotypes of focus formation and anchorage-independent growth. In contrast, the normal prostate cells showed diploid karyotype and lacked transformed phenotypes. Both the tumor and normal cells were positive for prostate-specific antigen and cytokeratins 18 and 19 and negative for keratin 15. These results demonstrate that the nondiploid prostate tumors and normal prostate epithelial cell cultures retained their respective in vivo properties and should allow studies to elucidate molecular alterations involved in human prostate cancer.

Biomarkers↗

PubMed1997

Contemporaneous bilateral pallidotomy.

To investigate the effects of bilateral posteroventral pallidotomy (PVP) for Parkinson's disease (PD), the authors reviewed the technique and neurological outcome in a number of patients who had undergone bilateral pallidotomy. The authors have previously reported the outcome of PVP in 25 bilateral and 25 unilateral surgeries, rating the patient's postural stability, speech, and total Unified Parkinson's Disease Rating Scale scores. A second, separate group of 23 patients who underwent contemporaneous bilateral PVP were evaluated for early onset idiopathic PD, levodopa failure syndrome, and severe bilateral dyskinesia as well as akinetic "off" states. Cognitive and psychological studies were reviewed in 10 patients who demonstrated preoperative impairments in spatial recognition and memory. Following surgery there were significant improvements in these cognitive deficits and no deficits were incurred by surgery. Published reports regarding bilateral operations for PD have emphasized the risks of speech and cognitive deficits. This study shows bilateral PVP to be effective, particularly in patients with bilateral symptoms, including disabling dyskinesia. Additionally, bilateral PVP does not cause additional cognitive or speech deficits. The techniques and indications as well as outcomes and complications are presented and discussed in this report in light of their controversial nature.

Journal Article↗

PubMed1997

Functional expression and apical localization of the cystic fibrosis transmembrane conductance regulator in MDCK I cells.

The gene product affected in cystic fibrosis, the cystic fibrosis transmembrane conductance regulator (CFTR), is a chlorideselective ion channel that is regulated by cAMP-dependent protein kinase-mediated phosphorylation, ATP binding and ATP hydrolysis. Mutations in the CFTR gene may result in cystic fibrosis characterized by severe pathology (e.g. recurrent pulmonary infection, male infertility and pancreatic insufficiency) involving organs expressing the CFTR. Interestingly, in the kidney, where expression of the CFTR has been reported, impaired ion transport in patients suffering from cystic fibrosis could not be observed. To understand the role of the CFTR in chloride transport in the kidney, we attempted to identify an epithelial cell line that can serve as a model. We demonstrate that the CFTR is expressed constitutively in Madine-Darby canine kidney (MDCK) type I cells, which are thought to have originated from the distal tubule of the dog nephron. We show expression at the mRNA level, using reverse transcriptase-PCR, and at the protein level, using Western blot analysis with three different monoclonal antibodies. Iodide efflux measurements indicate that CFTR expression confers a plasma membrane anion conductance that is responsive to stimulation by cAMP. The cAMP-stimulated iodide release is sensitive to glybenclamide, diphenylamine carboxylic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid, but not to 4,4'-di-isothiocyanostilbene-2,2'-disulphonic acid, an inhibitor profile characteristic of the CFTR chloride channel. Finally, the polarized localization of the CFTR to the apical plasma membrane was established by iodide efflux measurements and cell-surface biotinylation on MDCK I monolayers. Interestingly, MDCK type II cells, which are thought to have originated from the proximal tubule of the kidney, lack CFTR protein expression and cAMP-stimulated chloride conductance. In conclusion, we propose that MDCK type I and II cells can serve as convenient model systems to study the physiological role and differential expression of CFTR in the distal and proximal tubule respectively.

Animals↗

PubMed1997

Accumulation of phytate in vegetable-type soybean genotypes harvested at four developmental stages.

A total of 17 vegetable-type soybean (Glycine max [L.] Merr) genotypes were planted in four-row plots arranged in a randomized complete block design in 1988 and 1989 at Petersburg, Virginia. Each genotype was harvested at four developmental stages and evaluated for phytate content. Highly significant differences for phytate content were observed among the stages of harvest and genotypes, and there was an interaction between genotype x stage of harvest. The significant differences observed for phytate content among genotypes indicated that genetic variation exists among the tested genotypes for selection and improvement through hybridization. Among the genotypes, 'Kingston' and PI 423852 had the highest phytate content in most stages of harvest while PI 416771, 'Emperor', and PI 416982 had the lowest phytate values. A heritability estimate of 81 percent was observed for phytate content. This high heritability value indicates that selecting genotypes for lower phytate content would be effective. Significant correlations were observed for phytate content among genotypes harvested at R6, R7, R8, and overall. The magnitude of association of R6 with the overall phytate mean was especially high. These results illustrate that determining the phytate content of genotypes at the R6 growth stage would be a good predictor of the overall genotypic performance.

Food Analysis↗

PubMed1997

Registration bone scan in the evaluation of wrist pain.

We assessed the value of bone scintigraphy combined with X-ray registration for the diagnosis and management of wrist pain in 65 patients. Studies were reported independently by two observers before and after registration. Registration improved localization of scan abnormalities in 53% (observer 1) and 61% (observer 2). In these patients, the bone scan contributed to the diagnosis independently of the X-ray in 37% and the management was altered in 31%. The value of the bone scan in the early diagnosis and management of wrist pain is increased when it is registered with X-rays.

Adult↗

PubMed1997

Cytological aspects of uterine cervical adenocarcinoma, adenosquamous carcinoma and combined adenocarcinoma-squamous carcinoma: appraisal of diagnostic criteria for in situ versus invasive lesions.

This paper reports the cytological findings based on air-dried smears in a retrospective series of 143 cases of endocervical adenocarcinoma, combined adenocarcinoma-squamous carcinoma and adenosquamous carcinoma drawn from the files of the BC Cancer Registry. Cervical cytology smears were available before biopsy in 131 patients, but in 18 cases the cytology showed no abnormality. Malignant changes or high-grade atypia of glandular and/or squamous cells (defined as moderate or severe dyskaryosis) were detected in 103 cases. In 46 cases, only a high-grade squamous abnormality was detected. Low-grade glandular and/or squamous lesions were detected in nine cases and one showed atypical endometrial-type glands. The cervical smears of 64 cases were reviewed in detail to determine the important cytomorphological criteria of in situ and invasive adenocarcinoma in air-dried smears, the technique used for preparing PAP smears in British Columbia. Endocervical cells were absent in four cases. Numerous (> 10) groups of glandular cells were present in 51 cases. Important clues to the diagnosis of adenocarcinoma included crowding of nuclei, stratification of nuclei, loss of polarity, syncytial balls and papillary groups of glandular cells, nuclear enlargement, nuclear pleomorphism, and the presence of free-lying atypical glandular cells. Nuclear hyperchromatism, chromatin pattern, nuclear borders, nuclear membranes, and numbers and morphology of nucleoli were not helpful criteria in our material. Criteria enabling reliable distinction between in situ and invasive adenocarcinoma and/or mixed adenocarcinoma-squamous carcinoma could not be established.

Adenocarcinoma↗

PubMed1997

Establishment of a sandwich enzyme linked immunosorbent assay for canine interleukin-8.

To estimate canine interleukin-8 (cIL-8) levels in blood plasma samples, a sandwich enzyme linked immunosorbent assay (ELISA) was established. For the development of the sandwich ELISA, polyclonal anti-cIL-8 (capturing), biotinylated anti-cIL-8 (developing) antibodies and glutathione-S-transferase/cIL-8 (GST/cIL-8) fusion protein as an antigen were used. cIL-8 in the fusion protein of GST/cIL-8 was detected in a dose dependent manner. The lowest limit of GST/cIL-8 detectable by this method was 2 ng/ml of GST/cIL-8 (containing; 0.470 ng/ml of cIL-8). IL-8 levels in the plasma samples from apparently healthy dogs were less than 0.470 ng/ ml. Higher levels of IL-8 were detected in the plasma samples of dogs with cystitis, dermatitis, and gastric cancer. These results suggest that the determination of cIL-8 by the sandwich ELISA is useful in diagnosis of inflammatory diseases in dogs.

Animals↗

PubMed1997

Evaluation of MYC and chromosome 8 copy number in breast carcinoma by interphase cytogenetics.

We used fluorescence in situ hybridization (FISH) to determine MYC and chromosome 8 copy number on whole nuclear imprint preparations of 24 breast carcinomas, seven benign breast samples, and two phyllodes tumors. None of the benign tissues and neither of the phyllodes tumors demonstrated an increased copy number for MYC or chromosome 8, which was defined as greater than two signals in > 10% of nuclei. In contrast, 22 of 24 carcinomas demonstrated an increased MYC copy number. The modal numbers of MYC copies/nucleus were 0-2 in seven cases (29%), 3-5 in seven cases (29%), 6-9 in five cases (21%), and > 9 in five cases (21%). An increased chromosome 8 copy number was observed in 21 of 22 carcinomas with MYC gain, and the modal number of signals/nucleus was either identical to (n = 14; 64%) or less than (n = 8; 36%) the number of MYC copies. The number of MYC copies correlated with cellular DNA content, as determined by using flow cytometry. In peridiploid tumors (DNA index 0.9-1.2; n = 7), the MYC copy numbers/nucleus were 0-2 in five cases and 3-5 in two cases. In contrast, the modal MYC copy numbers/nucleus among the 11 hyperdiploid tumors (DNA index 1.3-1.9) were 0-2 in one case, 3-5 in four cases, 6-9 in five cases, and > 9 in one case. All three tetraploid/hypertetraploid carcinomas exhibited > 9 MYC copies/nucleus. We conclude that an increased MYC copy number, as detected by using interphase cytogenetics, is extremely frequent in human breast carcinomas. However, in most cases, MYC gene duplication is probably secondary to polysomy of chromosome 8 and/or genomic endoreduplication (i.e., DNA aneuploidy).

Aneuploidy↗

PubMed1997

Some pharmacodynamic and biochemical aspects of cefamandole.

The pharmacodynamic and nephrotoxic effects of cefamandole were investigated. Cefamandole at concentrations of 512 and 1024 micrograms/ml bath caused complete relaxation in isolated guinea pig ileum and rabbit duodenum, respectively. Concentrations of 2048 and 4096 micrograms cefamandole/ml bath caused marked stimulation in force and frequency of rat uterine muscle in all stages of sex cycle. Cefamandole in all tested concentrations did not induce any response on isolated guinea pig tracheal chain or isolated rabbit aortic strip. Cefamandole in concentrations of 256 to 1024 micrograms/ml bath as well as 256 and 512 micrograms/ml cannula produced marked inhibition on isolated guinea pig auricles and rabbit heart, respectively. The effect of graded increased concentrations on isolated frog gastrocnemius muscle, frog rectus abdominis muscle and rat phrenic nerve hemidiaphragm was recorded. Cefamandole in a dose of 53.2 mg/kg b. wt. in anaesthetized dogs caused very marked hypotensive effects and decrease in rate of respiration. Single intramuscular injection of cefamandole in a therapeutic (23.3 mg/kg b. wt.) and double therapeutic (46.6 mg/kg.b. wt.) doses in rabbits had no effect on electrocardiographic parameters among a period of 8 hours after injection. Effects of cefamandole on serum and urine concentrations of creatinine, urea, sodium, potassium, calcium, glucose and protein as well as clearance tests were investigated in rats.

Animals↗

PubMed1997

Synovial tissues collected from rheumatoid patients undergoing total joint arthroplasty express markers for acute inflammation.

Rheumatoid arthritis is an autoimmune disease that causes inflammation mainly in synovial tissues. RA manifests as a chronic polyarthritis with intermittent acute inflammatory episodes. The inflammatory sites are characterized by infiltration of activated lymphocytes and macrophages into the synovial membrane, and the proliferation of synovial cells. The local production of a number of cytokines by proliferative synovial cells as well as by infiltrating cells appears to account for many of the pathological and clinical manifestations in rheumatoid arthritis. Tissues were collected from twelve RA patients undergoing joint replacement surgery. The synovium was collected and the cell types were identified, and markers for chronic and acute inflammatory mediators were measured. The cells types found in the synovium are capable of secreting cytokines which are capable of both acute inflammation (IL-1, IL-6, IL-8, MCP-1 and TNF), as well as chronic inflammation (IL-2, IL-10, and IL-4). The results obtained showed that the macrophages-derived acute inflammatory cytokines (IL-1, IL-6 and IL-8) were easily detected at levels of 22.6 +/- 12 pg/mg protein; 48.5 +/- 42 pg/mg protein, and 76 +/- 31 pg/mg protein; respectively. T-cell derived chronic inflammation cytokines (IL-2, IL-4 and IL-10) were rarely detected. Retrieved tissues that immunostained positive for IL-6, IL-1 and IL-8 also is suggestive of an acute inflammatory response. The results clearly demonstrate that the acute response may be responsible for the subsequent need for joint arthroplasties.

Acute Disease↗

PubMed1997

Germinal cell alterations associated with sustained delivery of testosterone enanthate in adult male rats.

It is well documented that testosterone stimulates protein anabolism, muscular development, bone growth and increased metabolic rate. In addition, exogenous low levels of testosterone can inhibit the secretion of gonadotropins by the anterior pituitary. The objective of this study was to investigate the effect of sustained delivery of testosterone enanthate (TE) on the testicular architecture by means of tricalcium phosphate-lysine(TCPL). In this experiment adult male Sprague Dawley rats (250-300 g BW) were randomly divided into three equal groups (n = 16). Rats in group I were implanted subcutaneously with TE loaded TCPL implants (4-6 ng/ml). Rats in group II were implanted with sham TCPL capsules, and rats in group III served as intact unimplanted controls. Surgical aseptic techniques were performed according to standard laboratory procedures. At the end of 2 and 4 weeks post implantation, eight animals from each group were sacrificed and the testes were collected, weighted, and embedded for histopathological evaluations. The results of this study revealed the following: (i) Sustained delivery of TE reduced spermatogonia numbers in animals after 2 and 4 weeks by approximately 10% in comparison to control animals. (ii) The lumen of the tubules showed slight regression after 4 weeks of TE treatment. (iii) Overall decrease of the vasculature of the experimental animals was seen after 2 and continued through 4 weeks with an occasional increase of microvasculature seen in animals treated for 4 weeks with TE. (iv) Finally, the germinal epithelium showed significant reduction in secondary spermatocytes and conversion to mature sperm.

Animals↗

PubMed1996

Differential growth factor responses of epithelial cell cultures derived from normal human prostate, benign prostatic hyperplasia, and primary prostate carcinoma.

Because of a lack of information of the optimum nutritional requirements, epithelial cells derived from normal human prostate and prostate tumors have been difficult to propagate in vitro, which hinders research in prostate carcinogenesis. In an effort to establish optimum nutritional conditions and differences in growth characteristics of normal human prostate (NP), benign prostatic hyperplasia (BPH), and prostatic carcinoma (PCA), we have compared the effects of several growth factors on cell proliferation and elucidated growth properties of low passage epithelial cells derived from NP, BPH, and PCA of an African-American patient. Primary and low passage cultures were propagated in serum-free keratinocyte basal medium (KBM) supplemented with insulin (5 micrograms/ml), hydrocortisone (0.5 microgram/ml), epidermal growth factor (EGF, 10 ng/ml), bovine pituitary extract (BPE; 50 micrograms/ml), cholera toxin (10 ng/ml), and antibiotics. Almost all NP, BPH, and PCA cells were positive for cytokeratins and prostate-specific antigen (PSA). The NP, BPH, and PCA cells were essentially diploid and lacked mutations in c-K-ras and c-Ha-ras oncogenes, and p53 tumor suppressor gene. However, they exhibited progressively accelerating growth parameters. The population doubling times of NP, BPH and PCA were 51 hr, 37 hr, and 29 hr, respectively; their saturation densities were 2.9 x 10(4)/cm2, 3.3 x 10(4)/cm2, and 7.2 x 10(4)/cm2, respectively. The NP and BPH cells required all of the growth factors in the medium, as deletion of any one of the above factors strongly inhibited their growth. The PCA cells, however, were independent of EGF and hydrocortisone. PC-3, an established human prostate cancer cell line, was independent of the growth factors tested. Fetal bovine serum (FBS) inhibited the growth of NP, BPH and PCA cells. In contrast, FBS stimulated the growth of the PC-3 cells in a concentration-dependent manner. These results indicate that in the absence of any apparent karyotype alterations and mutations in c-K-ras, c-Ha-ras and p53 genes, epithelial cells derived from NP, BPH, and PCA exhibit significant differences in their growth properties and responses to growth factors. These variations may represent early changes involved in prostate cancer, while gene mutations and cytogenetic alterations occur in advanced and/or metastatic tumors.

Black or African American↗

PubMed1996

Production and characterization of polyclonal anti-canine interleukin-8 antibodies.

Polyclonal anti-canine interleukin-8 (cIL-8) antibodies were raised in rabbits immunized with cIL-8 expressed by E. coli. Polyclonal antibodies were purified by affinity chromatography. In the enzyme linked immunosorbent assay (ELISA), the resulting anti- cIL-8 antibodies showed relatively high reactivities with cIL-8 in the fusion proteins of glutathione-S-transferase/cIL-8 (GST/cIL-8) and maltose binding protein/cIL-8 (MBP/cIL-8), but negligible ones with MBP. Furthermore, Western blotting analysis using these polyclonal antibodies showed distinct bands for cIL-8, GST/cIL-8, and MBP/cIL-8. These antibodies also bound to recombinant human IL-8 (rhIL-8) in ELISA but not in Western immunoblotting. The rHIL-8 (50-800 ng/ml) was chemoattractant for canine neutrophils in a dose dependent manner, but the anti-cIL-8 antibodies did not show the inhibitory effect on the chemotactic activity of rhIL-8 of canine neutrophils, when tested by the chemotaxis assay using Boyden chambers. In addition, GST/cIL-8 and rhIL-8 induced strong and rapid shape change responses of canine neutrophils. However, the anti-cIL-8 antibodies inhibited shape change responses induced by GST/cIL-8 but not by rhIL-8.

ATP-Binding Cassette Transporters↗

PubMed1996

Immunochemical and histopathological evaluation associated with sustained delivery of 5-alpha androstanedione using adult rats as a model.

The specific objective of this study was to evaluate the effect of androstanedione (dihydrotestosterone (DHT)), delivered in a sustained manner by tricalcium phosphate lysine (TCPL) delivery devices, on the biochemical and cytological architecture of reproductive organs using adult rats as a model. A total of twenty four rats were distributed randomly into three equal groups. Rats in group II were implanted (S/C) with empty TCPL devices and served as sham controls. Group III rats were implanted with 1.51 (250 micrograms/day) g/cm3 CDD containing 300 mg DHT each. Group I animals served as unimplanted controls at time zero. Upon sacrifice (6 weeks), the prostatic tissue were collected, fixed, embedded, and sectioned (H&E) by using standard lab protocols. Data analysis of prostatic tissue obtained from rats implanted with such low density TCPL showed microscopic appearance varied somewhat from one area of the gland to another, but generally, there was considerable hyperplasia, as evidenced by accentuation of glandular folds and an increase in the number and size of the epithelial cells, with some areas of the gland showing more severe hyperplasia than others. Meanwhile, cross-sections of prostate obtained from rats implanted with empty CDD were characterized by an essentially normal histological appearance of the gland. These data exemplify the complex interactions which occur between prostate components and exogenous sustained delivery of DHT that are reflected in cell structure and function. Biochemical analysis of the serum revealed that there is remarkable reduction in HDL, and IL 1 (33%). In contrast the level of IL 6 increased (50%) in experimental animals compared to the sham operated animals. In conclusion, this experiment demonstrates that TCPL capsules are capable of delivering supraphysiological doses of DHT in a sustained manner for 6 weeks. The results also reveal that doses of DHT slightly above the physiological level can result in systemic toxicity. In addition, supraphysiological levels of DHT could cause severe BNH and regression to spermatogenesis after 6 weeks in rats, and an increase in the risk factors associated with CVD.

Animals↗

PubMed1995

Detection of the chemotactic factor for canine peripheral blood mononuclear cells and polymorphonuclear cells in the culture supernatant of Cos7 cells transfected with canine interleukin-8 cDNA.

Chemotactic activities in the culture supernatants of Cos7 cells transfected with a cloned canine IL-8 cDNA (pcIL-8SR alpha 14) were evaluated by using mononuclear cells (MNC) and polymorphonuclear cells (PMN) from the peripheral blood of dogs. The culture supernatants of Cos7 cells were collected 66 hr after the transfection of pcIL-8SR alpha 14 (Cos7/cIL-8). Chemotactic activities in the culture supernatants for MNC and PMN were determined as migration distances in Millipore membrane filters in a modified Boyden's chamber method. Peroxidase staining for MNC was effective not only for cells in cytospun smears but also for cells migrated in the filters. PMN in cytospun smears were well stained by peroxidase staining, whereas migrated PMN in the filters were stained weakly. Chemotactic activities in the culture supernatant of Cos7/cIL-8 cells for both MNC and PMN were significantly higher than those of control Cos7 cells. In addition, the culture supernatant of Cos7/cIL-8 cells was chemotactic for peroxidase negative nonadherent MNC (lymphocytes), but not for peroxidase positive adherent MNC (monocytes). This Cos7/cIL-8 supernatant also showed chemotactic activities for neutrophils in a dose dependent manner. These results suggest that the culture supernatant of Cos7/cIL-8 is chemotactic for lymphocytes as well as for neutrophils.

Animals↗