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Biomedical subjects

M El-Sawy

Publications and source records attributed to M El-Sawy.

15 recordsLinked to original sources
PubMed2005

Tandem insertions of Alu elements.

Alu elements are non-autonomous, non-LTR retroposons that represent the most abundant mobile elements in the human genome (1.1 x 10(6) copies/genome). They preferentially insert adjacent to existing Alu elements. It has been proposed that Alu elements utilize LINE-1 machinery for their retroposition. The LINE-1 endonuclease cleaves at a loose consensus sequence. We have utilized a bioinformatics approach to show the order of insertion of pairs of young (Y) and old (S or J) Alu subfamily members. Our data suggest that the consensus LINE-1 endonuclease cleavage site used for insertion of the old Alu elements can be reused for integration of the younger ones inserting adjacent to them. However, there is also a preference at the 3' end of Alu into a non-ideal cleavage site that may represent unique properties of the A-tail for integration. Alu elements inserting adjacent to one another may suggest the saturation of the optimal integration sites with existing Alu elements, rather than any innate preference for Alu elements to integrate adjacent to other Alus.

Alu Elements↗
PubMed2005

Human retroelements may introduce intragenic polyadenylation signals.

In the human genome, the insertion of LINE-1 and Alu elements can affect genes by sequence disruption, and by the introduction of elements that modulate the gene's expression. One of the modulating sequences retroelements may contribute is the canonical polyadenylation signal (pA), AATAAA. L1 elements include these within their own sequence and AATAAA sequences are commonly created in the A-rich tails of both SINEs and LINEs. Computational analysis of 34 genes randomly retrieved from the human genome draft sequence reveals an orientation bias, reflected as a lower number of L1s and Alus containing the pA in the same orientation as the gene. Experimental studies of Alu-based pA sequences when placed in pol II or pol III transcripts suggest that the signal is very weak, or often not used at all. Because the pA signal is highly affected by the surrounding sequence, it is likely that the Alu constructs evaluated did not provide the required recognition signals to the polyadenylation machinery. Although the effect of pA signals contributed by Alus is individually weak, the observed reduction of "sense" oriented pA-containing L1 and Alu elements within genes reflects that even a modest influence causes a change in evolutionary pressure, sufficient to create the biased distribution.

Base Sequence↗
PubMed1981

The skin window test in rhinoscleroma.

The skin window test was applied to evaluate the state of immunity in patients with rhinoscleroma. The use of the patient's own Klebsiella micro-organisms as antigen led to a negligible change in the percentage of lymphoblasts, whereas the use of foreign Klebsiella micro-organisms as antigen resulted in a pronounced change. This finding indicates an impaired cellular immune response. Application of Klebsiella microorganisms as antigen to normal subjects led to a comparatively high percentage of lymphoblastic transformation. This finding suggests the possible use of a standard Klebsiella antigen as a vaccine. The possible use of the skin window test to identify people with deficient T lymphocyte function is discussed as well as its use in monitoring the efficacy of such a vaccine in influencing the cellular immune response.

Antigens, Bacterial↗
PubMed1980

Serum phospholipid fractionation after the use of long-acting progestational contraceptives.

The effect of the two long-acting progestational contraceptive injection, depot-medroxyprogesterone acetate (DMPA) and norethisterone onenathate (NET-OEN), on blood phospholipid fractions were studied in eighteen women. The post-injection results showed a significant increase in total serum phospholipids, serum lecithin and serum cephalins. Serum lysolecithin was significantly decreased while serum sphingomyelin showed no significant change. The mechanisms responsible for these phospholipid changes remain somewhat unclear. However deranged liver function may share in its explanation.

Adult↗
PubMed1978

Study of chemical constituents of thoracic duct lymph in schistosomal hepatic fibrosis.

Concentrations of serum and thoracic duct proteins, immunoglobulins, lipids, enzymes and electrolytes were estimated in 15 patients with schistosomal hepatic fibrosis and presinusoidal obstruction and in 12 controls. There was a significant decrease of thoracic duct total proteins, albumin and triglycerides, with marked and significant increase in IgG and IgM in SHF, compared to the controls. The levels of transaminases, alkaline phosphatases and inorganic phosphorus were significantly higher in the lymph of SHF patients compared with healthy controls. It is presumed that these changes represent the pattern of lymph constituents in presinusoidal obstruction.

Adult↗
PubMed1977

Schistosoma haematobium egg counts in a Nile delta community.

A study of Schistosoma haematobium egg counts was made in a community near Alexandria. This showed that the intensity of infection was similar to that which has been reported in some of the comparable surveys which have been made in sub-Saharan Africa. This finding highlights the need for further studies in defined communities of the pathogenicity of the infection. The egg counts of subjects who recalled treatment with tartar emetic within the last two years were similar to those who said they had never been treated. This suggests that the cost effectiveness of chemotherapeutic methods needs further evaluation.

Adolescent↗
PubMed1977

Studies on protein production by yeasts. III. Effects of different levels of nitrogen and phosphorus.

The four strains of yeasts that gave good growth in molasses medium, short generation time, and high protein content were selected for further studies in a trial for increasing their yield and protein content. Therefore, the effect of different levels of ammonium sulphate and potassium dihydrogen phosphate on the growth and protein synthesis of the strains was investigated, using molasses as a source of carbon. The results revealed that the most suitable concentrations of ammonium sulphate in the propagation medium lie between 0.40 to 0.55% for the production of high yield and protein content of strains S. cerevisiae (Gr. 104), C. utilis (F. 86), C. tropicalis (F. 35), and H. anomala (Gr. 5). The optimum concentration of potassium dihydrogen phosphate lies between 0.2 to 0.3% for the same strains. S. cerevisiae (Gr. 104) seemed to be the most efficient strain that gave the best growth, high percentage of protein, and essential amino acids in molasses medium.

Amino Acids↗
PubMed1977

Studies on protein production by yeasts. IV. Incremental feeding modulus.

S. cerevisiae Gr. 104 which seemed to be the most efficient strain in protein production, was used for investigating its optimum incremental feeding modulus that gives the highest economical yield. Therefore, different hourly rates of incremental feeding, ranging from 1.14 to 1.22, were used and the yeast yield for each rate was determined. Experiments were carried out in a laboratory fermentor vessel of 5 liter capacity, using molasses, ammonium sulphate, and potassium dihydrogen phosphate as feeding substances with optimum pH, temperature, and effective aeration. The optimum incremental feeding for this strain (which is the rate of molasses feeding corresponding to the exponential growth rate) was found to be 1.18. At this rate the best economical use of the substrate was obtained with the production of yield, close to the theoretically calculated yield.

Agriculture↗
PubMed1976

Studies on some nutritional factors influencing the production of gluconic acid.

Investigations were carried out to formulate an economical medium that can give maximum yield of gluconic acid by the submerged culture technique, using Aspergillus niger NRRL3. It was found that the highest yield of acid could be secured when a medium of the following ingredients was used: 13.0% glucose syrup, 0.1% NaNO3, 0.025% calcium superphosphate, 0.007% KCl, 0.025% MgSO4-7H20, and 0.5% CaCO3. It was also found that glucose syrup, which represents an available and cheap carbohydrate source for gluconic acid production by fermentation, can replace glucose powder which is more expensive.

Aspergillus↗