Biomedical subjects

A Mohamed

Publications and source records attributed to A Mohamed.

At least 73 records · Page 4Linked to original sources

PubMed1995

Enhancing effects of chicken egg white derivatives on the phagocytic response in the dog.

Immunostimulative effects of chicken egg white derivatives (EWD) on phagocytic responses of peripheral blood mononuclear cells (MNC) and polymorphonuclear cells (PMN) in dogs were evaluated by flow cytometric analysis. Peripheral blood leukocytes (PBL) cultured with EWD showed the enhanced phagocytic response. The response was maximal when PBL were cultured with 100 - 400 micrograms/ml of EWD for 3 - 12 hr. Furthermore, significantly increased phagocytic responses were also induced even when PBL were cultured with protein components (200 micrograms/ml) of EWD such as conalbumin, flavoprotein and ficin-papain inhibitor for 3 hr. In addition, the enhancing effect of EWD on the phagocytic responses was also observed in MNC cultured with EWD (200 micrograms/ml) for 4 hr but not in PMN cultured with EWD in the same procedures. The supplement of the supernatant (20%) of MNC cultured with EWD (200 micrograms/ml) for 24 hr at 37 degrees C to PBL and MNC resulted in the enhancement of their phagocytic responses. In contrast, the supernatant of PMN cultured with EWD for 24 hr at 37 degrees C did not show any significant enhancing effect on the phagocytic responses of PBL, MNC and PMN. These results suggest that EWD has an enhancing effect on phagocytosis of MNC and PMN, which may be mediated through active humoral substances produced by EWD-stimulated MNC.

Adjuvants, Immunologic↗

PubMed1995

Anatomic considerations for dorsal sacral plate-screw fixation.

Five cadaveric pelves and 40 dry bony specimens were used to assess the feasibility of the lumbosacral plate fixation extending to beyond the S1 region and quantitatively to evaluate the posterior sacroiliac region and the dimensions of S1 and S2 pedicle and lateral mass. Partial removal of the posterior ilium was undertaken to measure the surface area available for plate fixation on the dorsal aspect of the sacrum. The results showed that the average distances between the outer edges of S1 and S2 dorsal foramina and the medial edge of the posterior ilium increased from 11.3 mm before removal of a portion of the medial posterior ilium to 16.6 mm after removal at the S1 level, and from 8.4 mm before removal of partial medial posterior ilium to 13 mm after removal at the S2 level, respectively. The average depths of the S1 and S2 pedicles were 37.1 and 32.2 mm in the direction anteromedial to the sagittal plane, respectively. The average depths of the S1 and S2 lateral mass were 37.3 and 33.9 mm in the direction anterolateral to the sagittal plane, respectively. In cases of vertebral metastases or osteoporosis, plating extending to S2 may be needed if good bony purchase cannot be achieved by the S1 pedicle or lateral mass screw. This study suggested also that partial removal of the posterior ilium enhances the space on the posterior aspect of the sacrum without severe compromise of the sacroiliac joint.

Aged↗

PubMed1994

Conformational maturation of CFTR but not its mutant counterpart (delta F508) occurs in the endoplasmic reticulum and requires ATP.

Metabolic labeling experiments followed by immunoprecipitation were performed to investigate the kinetics, location and inhibitor sensitivity of degradation of both wild-type (wt) and mutant (delta F508) cystic fibrosis conductance transmembrane regulator (CFTR). At the earliest stages of the biosynthetic process, both wt and delta F508 CFTR were found to be susceptible to degradation by endogenous proteases. Virtually all delta F508 CFTR and 45-80% of wt CFTR were rapidly degraded with a similar half-life (t1/2 approximately 0.5 h). The remaining wt CFTR attained a protease-resistant configuration regardless of whether traffic between the endoplasmic reticulum (ER) and Golgi was operational. Metabolic energy is required for the conformational transition, but not to maintain the stability of the protease-resistant wt CFTR. Intracellular degradation of delta F508 CFTR and of incompletely folded wt CFTR occurs in a non-lysosomal, pre-Golgi compartment, as indicated by the sensitivity of proteolysis to different inhibitors and temperature. Accordingly, products of the degradation of delta F508 CFTR could be detected by immunoblotting in isolated ER, but not in the Golgi. Together, these results suggest a dynamic equilibrium between two forms of wt CFTR in the ER: an incompletely folded, protease-sensitive form which is partially converted by an ATP-dependent process to a more mature form that is protease-resistant and capable of leaving the ER. The inability delta F508 CFTR to undergo such a transition renders it susceptible to complete and rapid degradation in a pre-Golgi compartment.

Adenosine Triphosphate↗

PubMed1994

Molecular cloning and expression of canine interleukin 8 cDNA.

Molecular cloning of canine interleukin-8 (IL-8) was performed to establish a basis for its investigation in the canine immune system. From a cDNA pool constructed from LPS-stimulated popliteal lymph node cells, canine IL-8 cDNA covering the whole coding region was amplified by polymerase chain reaction. The nucleotide sequence of a canine IL-8 clone, designated pcIL-8#38, was highly similar to those of human, rabbit and porcine IL-8, and comprised 353 bp with an open reading frame that encoded 101 amino acids. Analysis of the deduced amino acid sequence of insert DNA in pcIL-8#38 showed 76.5, 80.2, and 87.0% similarities with human, rabbit and porcine IL-8 proteins, respectively. Insert DNA of pcIL-8#38 was transferred to a mammalian expression vector, pcDL-SR alpha 296, and transfected into Cos7 cells. The supernatant of the transfectant had neutrophil chemotactic activity when it was examined by the neutrophil migration assay, suggesting that our cloned cDNA was biologically active. The cloned canine IL-8 cDNA will be useful for canine inflammatory disease and comparative immunology research.

Amino Acid Sequence↗

PubMed1993

The delta F508 mutation decreases the stability of cystic fibrosis transmembrane conductance regulator in the plasma membrane. Determination of functional half-lives on transfected cells.

Deletion of the phenylalanine at position 508 of the cystic fibrosis transmembrane conductance regulator (CFTR) is the most prevalent mutation in cystic fibrosis (CF). This mutation (delta F508CFTR) leads to a reduced cAMP-sensitive Cl- conductance in epithelial cells. While the mutant protein can function as a Cl- channel, it seems to be misprocessed and unable to accumulate at normal levels in the plasma membrane. Under conditions where the biosynthetic block of delta F508CFTR is not complete, the residence time of delta F508CFTR in the plasma membrane is a critical determinant of the cAMP-sensitive Cl- conductance. To assess the stability of the mutant and wild-type CFTR, we compared their functional half-lives at the plasma membrane of transfected Chinese hamster ovary cells. The plasma membrane Cl- conductance was assessed by patch-clamp recordings and/or by fluorimetric determinations of the membrane potential. Accumulation of delta F508CFTR in the plasma membrane was promoted by growing the transfected cells at reduced temperature (24-28 degrees C), and was verified by immunoblotting and by detecting the appearance of a plasmalemmal cAMP-activated Cl- conductance. Subsequently increasing the temperature to 37 degrees C inhibited further delivery of newly synthesized delta F508CFTR to the surface membrane. By studying the time dependence of the disappearance of the Cl- conductance, the functional half-life of the mutant protein at the plasma membrane was determined to be < 4 h, which is considerably shorter than the half-life of wild-type CFTR (> 24 h). The latter was estimated by terminating protein synthesis or secretion with cycloheximide or brefeldin A, respectively. Inhibition of protein synthesis did not alter the rate of disappearance of delta F508CFTR at 37 degrees C, validating the difference in turnover between mutant and wild-type CFTR. These results indicate that the structural abnormality of delta F508CFTR affects not only the delivery of the protein to the plasma membrane, but also its stability therein. Moreover, they suggest that overcoming the processing block at the endoplasmic reticulum may not suffice to restore normal Cl- conductance in CF.

Animals↗

PubMed1993

Busulfan-based regimens and allogeneic bone marrow transplantation in patients with myelodysplastic syndromes.

Preparative regimens containing busulfan (BU) followed by allogeneic bone marrow transplantation (BMT) were used in 27 consecutive patients with myelodysplastic syndromes (MDS). The median age was 33 years (range, 4 to 54). Ten were female and 17 male. Sixteen patients had primary MDS, 11 other patients had antecedent hematologic diseases or developed MDS after cytotoxic and/or radiation therapy. Six patients had leukemic transformation and received antileukemic therapy before BMT. Pre-BMT cytogenetic studies showed complex chromosomal abnormalities in 13 patients, a simple abnormality in 5 patients, and normal chromosome in 8 patients. Three BU-based preparative regimens were used: 1 patient received BU 4 mg/kg orally (PO) daily for 4 days and cyclophosphamide (CY) 50 mg/kg intravenously (IV) daily for 4 days (BUCY-4); 24 patients received BU 4 mg/kg PO daily for 4 days, cytosine arabinoside (ara-C) 2 g/m2 IV every 12 hours for 4 doses, and CY 60 mg/kg IV daily for 2 days (BAC); and 2 patients with preceding Fanconi anemia received BU 2 mg/kg PO daily for 4 days followed by total lymphoid irradiation of 5 Gy. Seventeen of 27 patients are alive with no evidence of disease. Ten patients have died: 2 from hepatic veno-occlusive disease, 3 from sepsis, 1 from a cerebral bleed, 1 from a massive gastrointestinal (GI) bleed associated with acute graft-versus-host disease, 1 from hemolytic uremic syndrome with adult respiratory distress syndrome, 1 from bronchiolitis obliterans, and the only patient who did not engraft died from acute myeloid leukemia. Regimen-related toxicities (RRT) include GI tract (diarrhea, 14; stomatitis, 11), liver (9), cardiac (1), and skin (5). Patients who received a genotypically matched marrow graft had a significantly better disease-free survival (DFS) than patients who received a nongenotypic marrow graft (P = .02). The Kaplan-Meier analysis projects an overall DFS of 56% +/- 13% and 78% +/- 10% for patients who received a genotypically matched marrow graft. With the exception of a child who did not engraft, there was no relapse of MDS or leukemia. Excellent DFS, acceptable RRT, and the ease of administration are advantages of this regimen.

Adolescent↗

PubMed1993

Differential expression of the psbA genes in the cyanobacterium Synechocystis 6803.

The 5' region and transcription initiation sites of the psbA-2 and psbA-3 genes of Synechocystis 6803 were determined. The otherwise highly homologous genes were shown to diverge significantly in the 5' noncoding regions. The transcription start site for the psbA-2 gene was mapped to position -49 upstream of the coding region and for the psbA-3 gene to position -88, i.e. 38 bp upstream of the psbA-2 transcription start point. Both genes exhibit promoter elements, which conform in sequence and position to Escherichia coli consensus motifs. The two genes share identical -35 sequences but differ in their -10 sequences. Primer extension analysis demonstrated that the psbA-2 and psbA-3 genes are differentially expressed, with > 90% of the total psbA transcripts being produced by the psbA-2 gene and the rest by the psbA-3 gene. Inactivation of the psbA-2 gene resulted in an eightfold up-regulation of the psbA-3 gene. The strikingly higher stability of the psbA transcripts in darkness compared to light, and the accumulation of a specific decay intermediate under dark conditions was reported previously. We show here that this dark-stability applies to both the psbA-2 and psbA-3 transcripts. The psbA-3 transcript did not appear to produce the processed intermediate, arguing for the involvement of the 5' non-coding region as a determinant in psbA transcript degradation.

Bacterial Proteins↗

PubMed1992

Cytogenetics of primary prostatic adenocarcinoma. Clonality and chromosome instability.

We have examined 62 prostatic adenocarcinomas by conventional cytogenetic analysis. Most were primary cultures harvested in 14 days or less. The most consistent finding was a normal male diploid karyotype, found in 87% of all cells analyzed, and as the exclusive finding in 19 tumors. Nonrandom chromosomal changes included gain of chromosome 7 and loss of the Y chromosome. In addition, clonal gains of chromosomes 8, 12, and 18, and clonal losses of chromosomes 14 and 19 were noted in individual cases. Two structural clonal aberrations, a 9p+ in one case and a t(Y;22) (q11.2;p12) in another, were also seen. Ten of 62 cultures demonstrated chromosome instability, defined herein as nonclonal gain or loss of chromosomes in more than 10% of the metaphases examined from that culture. In those cases with nonclonal numerical aberrations, loss of chromosomes was more common than gain. The distribution of apparently random numeric abnormalities was similar to that of the clonal abnormalities in that the most frequent nonclonal gain was of chromosome 7 and the most frequent nonclonal loss was of the Y chromosome. Apparently random structural aberrations were observed in less than 1% of all analyzed cells. These included a 4p-,del(3)(q13), and t(1;11). The extent of apparently random aneuploidy suggests that chromosome instability characterizes cultured prostatic adenocarcinomas. An increase in the frequency of nonclonal aberrations may be an indicator of tumor origin in a predominantly diploid cell population. The coexistence of clonally aberrant, nonclonally aberrant, and normal diploid cells in culture may reflect heterogeneity of prostate tumors in vivo.

Adenocarcinoma↗

PubMed1992

Ultrasonographic changes of the liver in Schistosoma haematobium infection.

Abdominal ultrasonographic examination was performed in 61 hospitalized patients with chronic liver diseases and 253 school children from a village endemic for Schistosoma haematobium and were compared with 142 urban children without exposure to Schistosoma. The prevalence of ultrasound-detectable hepatomegaly and splenomegaly and the degree of periportal fibrosis was compared between those with and without S. haematobium infection. Among 13 patients with biopsy-proven schistosomal hepatic fibrosis, three with coarse changes secondary to S. mansoni infection showed grade III periportal fibrosis, while 10 patients with fine schistosomal hepatic fibrosis due to S. haematobium had borderline (two) or grade I (eight) changes. Ultrasound evidence of periportal fibrosis was not detected in patients with hepatic cirrhosis, chronic active hepatitis, or fatty infiltration. However, three of 14 patients with chronic persistent hepatitis had grade I periportal fibrosis and two had borderline changes. The frequency of ultrasound-detected hepatomegaly and splenomegaly was greater among rural S. haematobium-infected children (35.2% and 22.4%, respectively) than among noninfected rural (21.1% and 13.3%) and urban (16.9% and 4.9%) children. Also, the frequency of grade I periportal fibrosis was significantly greater (P less than 0.01) in S. haematobium-infected children (22.4%) than in noninfected rural (11.7%) and urban (0.7%) children. No patients with S. haematobium infections, either in the hospital or the village, had grade II or III periportal fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗

PubMed1992

Allogeneic bone marrow transplantation in high-risk myeloid disorders using busulfan, cytosine arabinoside and cyclophosphamide (BAC).

Twenty-one patients (median age = 34, range = 10-49; F:M = 7:14) received a preparative regimen consisting of busulfan 4 mg/kg/day x 4, cytosine arabinoside 2 g/m2/12 h x 4 and cyclophosphamide 60 mg/kg/day x 2 ('BAC' regimen) for allogeneic bone marrow transplantation. Out of 12 patients with acute myeloid leukemia (AML), two were in first remission, six were in second remission and four had resistant, relapsed disease or prolonged marrow aplasia after induction chemotherapy. Five of the 12 patients with AML had secondary AML. Four patients had transfusion-dependent myelodysplastic syndrome. Three patients with chronic myeloid leukemia were in the accelerated phase and two were in the blastic phase. Organ toxicities related to the preparative regimen were graded. Liver toxicity occurred in 11 patients, two of these were fatal veno-occlusive disease (VOD) (10%). Nineteen of the 21 patients had grade 2 or less diarrhea, and 13 also had mucositis. One patient developed grade 3 cardiac toxicity, and one other patient had grade 1 skin toxicity. Four patients had gross hematuria related to treatment (19%). No renal, pulmonary or CNS toxicities were encountered. Ten patients have died, two from regimen-related hepatic VOD. Of the remaining eight deaths, four were from respiratory failure in four patients (one case each of Pneumocystis pneumonia, CMV pneumonia, bronchiolitis obliterans associated with chronic graft-versus-host disease, and interstitial pneumonitis complicated pulmonary emboli), and one patient each from GI bleeding, cardiac arrhythmia, sepsis and CNS bleeding. Thus far, only one patient transplanted for secondary AML in second remission relapsed at day 230.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Molecular cloning and chromosomal mapping of a human galactoside-binding protein.

A human galactoside-binding protein with an Mr of 31,000 was cloned from the human HT-1080 fibrosarcoma complementary DNA library. A partial complementary DNA clone containing the complete coding region was characterized and the deduced sequence encodes a polypeptide of 242 amino acids with the characteristics of a carbohydrate-binding protein. The gene coding for the human galactoside-binding protein was mapped to the chromosomal band 1p13. The deduced amino acid sequence of the human galactoside-binding protein revealed 95 residues at the amino terminus, homologous to the predicted amino acid sequence of the second exon of the human L-myc gene.

Amino Acid Sequence↗

PubMed1991

Photosynthetic electron transport controls degradation but not production of psbA transcripts in the cyanobacterium Synechocystis 6803.

Accumulation and stability of psbA and rbcL-S transcripts in Synechocystis 6803 was followed in the presence and absence of the photosynthesis inhibitors DCMU and methylviologen. Our results demonstrate that both transcript production and transcript stability are important regulatory elements for psbA gene expression in Synechocystis 6803. The production of psbA transcripts was stimulated by light in a process that operated independently of the photosynthetic electron transport. However, stability of the psbA transcript increased in the dark and was controlled by photosynthetic electron transport. The psbA transcript was remarkably stable in the dark, with a half-life of approximately 7 hours. By contrast, the regulatory pattern for the rbcL-S genes was quite different. The light-stimulated production of rbcL-S transcripts was dependent on an intact photosynthetic electron transport, and rbcL-S transcript stability was higher under illuminated conditions than in darkness.

Blotting, Northern↗

PubMed1991

Cytogenetic study of a papillary thyroid carcinoma with a rearranged chromosome 10.

Cytogenetic findings of a multifocal papillary thyroid cancer and a metastatic lymph node from a 29-year-old white female patient are reported. Two clonal aberrations were observed: a trisomy 7 in one nodule, and a rearranged chromosome 10 in a separate nodule and in a lymph node. The rearrangement of 10q described here is similar to other published cases and is relevant for interpreting the molecular findings associated with thyroid cancer.

Adult↗

PubMed1991

Superior sagittal sinus thrombosis.

Seven cases of superior sagittal sinus thrombosis seen at Royal Prince Alfred Hospital over the 10 year period 1979 to 1989 have been reviewed. Diagnosis was confirmed by angiography, CT scan or autopsy. The average age was 33 years (16 to 47 years). Five of the patients were female and 2 male. On CT scan the 'empty delta' sign, present in 4 cases, was the most specific diagnostic feature. The underlying causes included primary thrombocythaemia, homocystinuria, post-angiographic investigation of an arteriovenous malformation, and oral contraceptives. In 2 cases no cause was found. Headache was the commonest and earliest symptom, being followed in frequency by convulsions and hemiparesis. Hemiparesis was the commonest sign observed, followed by papilloedema, cranial nerve palsies and impaired level of consciousness. Five of the patients developed signs and symptoms of raised intracranial pressure prior to the appearance of focal neurological deficits, mostly likely due to propagation of the thrombosis to cortical veins. There have been no controlled trials of therapy; however it is important to treat raised intracranial pressure rapidly and effectively, and although the role of anticoagulants remains controversial, their early use may be indicated when there is no radiological evidence of haemorrhage.

Adolescent↗

PubMed1989

Influence of light on accumulation of photosynthesis-specific transcripts in the cyanobacterium Synechocystis 6803.

Transcript accumulation for the psbA, psbD, psbD-C, rbcL-S and rrn genes in Synechocystis 6803 was followed under different light conditions. psbA, psbD, psbD-C and rbcL-S transcripts required light to accumulate and the relative abundance of these transcripts differed between high and low light conditions. Under high light conditions, steady-state levels of psbA, psbD and psbD-C transcripts were higher while levels of rbcL-S transcripts were lower than under low light conditions. rrn transcripts accumulated in the dark and the transcript levels were the same under illuminated conditions. Analyses of constructed Synechocystis 6803 mutants showed that both psbA-2 and psbA-3 could produce high levels of transcripts under illuminated conditions. No psbA-1 transcripts were detected.

Cyanobacteria↗

PubMed1988

Oesophageal pemphigus vulgaris.

Symptomatic involvement of the oesophageal mucosa by pemphigus vulgaris is rare. We describe 1 patient who was treated with oral steroids during a blistering phase, when epigastric pain developed. Endoscopy revealed multiple ulcerations all over the oesophagus, but gastroduodenal mucosa was normal. The symptoms disappeared following cimetidine for gastro-oesophageal reflux and increase of steroid dosage. When painful symptoms appear from the upper digestive tract during corticosteroid treatment of pemphigus, the possibility of acantholytic involvement of oesophageal mucosa must be kept in mind. Its implication for the dosage of steroids is opposite that in steroid-induced peptic ulcers. Carefully performed upper gastrointestinal tract endoscopy is helpful in these patients.

Adult↗

PubMed1987

Alpha-ecdysone, a new bracken fern factor responsible for neoplasm induction in the Egyptian toad (Bufo regularis).

Neoplastic lesions were induced in 10 out of 58 experimental toads (Bufo regularis) force-fed with alpha-ecdysone, which naturally occurs in the leaves of bracken fern (Pteris aquilina). The results of this study prove that alpha-ecdysone may be one of the factors responsible for the carcinogenicity of bracken fern plant fed to cattle and other experimental animals.

Animals↗

PubMed1984

A microenzyme-linked immunosorbent assay for urinary albumin, and its comparison with radioimmunoassay.

Interest in early albuminuria ('microalbuminuria') has intensified recently, particularly in the area of diabetes. We describe a sandwich type enzyme-linked immunoassay for urinary albumin and compare it with a conventional radioimmunoassay (RIA) using the same commercial antiserum. The assay ranges for ELISA and RIA were 7.5-500 micrograms/l and 20-5000 micrograms/l respectively and the corresponding sensitivities were 1.5 ng and 2.0 ng. The correlation coefficient between ELISA and RIA in the measurement of albumin in overnight urine samples from 74 children was r = 0.89 (P less than 0.001). ELISA has several practical advantages over radioimmunoassay, and we believe it has the potential to replace RIA in the screening and study of albuminuria.

Albuminuria↗