Rapid carrier screening using short tandem repeats in the phenylalanine hydroxylase gene.

Phenylketonuria (PKU) is an autosomal recessive genetic disorder caused by defects in the phenylalanine hydroxylase (PAH) system. Our work aimed to screen the PAH locus for the presence of potentially useful short tandem repeats (STR) as markers for carrier detection in PKU families in Egypt, and to determine the level of PAH heterozygosity within the Egyptian population. The system contains at least eight independent alleles in the Egyptian population, transmitted in a Mendelian fashion. Variations in the number of STR in the 16 families studied gave rise to polymorphisms that proved to be suitable markers for PKU carrier detection and prenatal diagnosis. The most frequent allelic fragment size in PKU patients was 246 bp (35.7%), which together with a fragment of 254 bp accounted for 60.7% of the mutant chromosomes.

Rapid carrier screening using short tandem repeats in the phenylalanine hydroxylase gene

Phenylketonuria [PKU] is an autosomal recessive genetic disorder caused by defects in the phenylalanine hydroxylase [PAH] system. Our work aimed to screen the PAH locus for the presence of potentially useful short tandem repeats [STR] as markers for carrier detection in PKU families in Egypt, and to determine the level of PAH heterozygosity within the Egyptian population. The system contains at least eight independent alleles in the Egyptian population, transmitted in a Mendelian fashion. Variations in the number of STR in the 16 families studied gave rise to polymorphisms that proved to be suitable markers for PKU carrier detection and prenatal diagnosis. The most frequent allelic fragment size in PKU patients was 246 bp [35.7%], which together with a fragment of 254 bp accounted for 60.7% of the mutant chromosomes

Laboratory evaluation of a Helicosporidium sp. (Protozoa: Helicosporida) as an agent for the microbial control of mosquitoes.

A Helicosporidium sp. isolated from diseased larvae of Culex pipiens L. in Egypt was assessed for its microbial control potential against mosquito larvae. Dose infectivity and dose mortality of the pathogen was determined for each larval instar of Cx. pipiens. Helicosporidium sp was infectious to Aedes caspius (Pallas), C. antennatus (Becker), C. perexiguus Theobald, and Culiseta longiareolata (Macquart). Using 24-hr exposures of first instar larvae to a range of concentrations between 50 and 5 x 10(3) spores/ml, Cx. antennatus and Cx. perexiguus were more susceptible than Cx. pipiens, Ae. caspius and Cs. longiareolata with LC50's of 5 x 10(2), 5 x 10(2), 1.6 x 10(3), 1.4 x 10(3), and 1.7 x 10(3), respectively. Current experiments shown that Helicosporidium spores were tolerant of freezing and storage at 5 degrees C, but not to desiccation. Production trails indicated that up to 6.2 x 10(8) spores could be routinely produced in individual cotton leaf worms, Spodoptera littolaris (Boisd) (Lepidoptera: Noctuidae).

Molecular diagnosis of spinal muscular atrophy in Egyptians.

This study was carried out with 33 spinal muscular atrophy (SMA) patients. DNA molecular studies of the SMA gene on the long arm of chromosome 5 (5q11.2q13.3) revealed homozygous deletion of exon 7 in 55% of cases, 36% of whom also had a homozygous delition of exon 8. The adult patients were heterozygous for an abnormal size exon 8. The remaining patients had either compound heterozygote deletion of exons 7 and 8 or were normal for both. There may therefore be 5q-unlinked SMA or SMA due to other mutations. Detection of deletions of SMA exons 7 and 8 is a powerful diagnostic test in patients with SMA, but other mutations among Egyptians must also be sought.

Molecular diagnosis of spinal muscular atrophy in Egyptians

This study was carried out with 33 spinal muscular atrophy [SMA] patients. DNA molecular studies of the SMA gene on the long arm of chromosome 5 [5q11.2q13.3] revealed homozygous deletion of exon 7 in 55% of cases, 36% of whom also had a homozygous delition of exon 8. The adult patients were heterozygous for an abnormal size exon 8. The remaining patients had either compound heterozygote deletion of exons 7 and 8 or were normal for both. There may therefore be 5q-unlinked SMA or SMA due to other mutations. Detection of deletions of SMA exons 7 and 8 is a powerful diagnostic test in patients with SMA, but other mutations among Egyptians must also be sought

Chironomid potent allergens causing respiratory allergy in children.

Generally speaking, chironomids contain potent inhalant allergens. The skin prick tests with chironomid crude extract (Chironomus (C.) calipterus) were positive in 20 out of 25 children with respiratory allergy. The skin prick tests with house dust mite crude extract (Dermatophagoides pteronyssinus) were positive in 3 of these 20 chironomoid positive skin tests. Chironomid-specific IgE-ELISA were demonstrated in the sera of 17 (85%) of the chironomid skin positive patients. These 17 patients gave negative skin prick test to house dust mite crude extract. It is concluded that chironomid allergens should be considered when dealing with human respiratory allergy caused by arthropods.

Development of a plant-derived subunit vaccine candidate against hepatitis C virus.

Hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis with over 180 million cases worldwide. Vaccine development for HCV has been difficult. Presently, the virus cannot be grown in tissue culture and there is no vaccine or effective therapy against this virus. In this research, we describe the development of an experimental plant-derived subunit vaccine against HCV. A tobamoviral vector was engineered to encode a consensus sequence of hypervariable region 1 (HVR1), a potential neutralizing epitope of HCV, genetically fused to the C-terminal of the B subunit of cholera toxin (CTB). This epitope was selected from among the amino acid sequences of HVR1 "mimotopes" previously derived by phage display technology. The nucleotide sequence encoding this epitope was designed utilizing optimal plant codons. This mimotope is capable of inducing cross-neutralizing antibodies against different variants of the virus. Plants infected with recombinant tobacco mosaic virus (TMV) engineered to express the HVR1/CTB chimeric protein, contained intact TMV particles and produced the HVR1 consensus peptide fused to the functionally active, pentameric B subunit of cholera toxin. Plant-derived HVR1/CTB reacted with HVR1-specific monoclonal antibodies and immune sera from individuals infected with virus from four of the major genotypes of HCV. Intranasal immunization of mice with a crude plant extract containing the recombinant HVR1/CTB protein elicited both anti-CTB serum antibody and anti-HVR1 serum antibody which specifically bound to HCV virus-like particles. Using plant-virus transient expression to produce this unique chimeric antigen will facilitate the development and production of an experimental HCV vaccine. A plant-derived recombinant HCV vaccine can potentially reduce expenses normally associated with production and delivery of conventional vaccines.

Trichinella encysted larvae in slaughtered pigs in Cairo (1995-1999).

Trichinosis is one of the most serious meat borne parasites. Examination of pigs in the slaughtered houses over the last five years showed an overall rate of 1.691%. The trichinoscope and sometimes the muscle digestion technique were adopted to diagnose infection. Trichinosis as a zoonotic parasitic disease was discussed.

An enzyme-linked immunosorbent assay for detection of IgG1 antibodies specific to human cystic echinococcosis in Egypt.

Human cystic hydatidosis (cystic echinococcosis) is a chronic zoonotic disease that results from infection with the dog tapeworm Echinococcus granulosus. In Egypt, cystic echinococcosis (CE) is recognized in slaughtered livestock by veterinarians, however, there is little information about human CE infection rates. We describe an immunological assay useful for the diagnosis of human cystic hydatidosis. Sera were collected from surgically confirmed hydatid cases (34), nonendemic subjects free from parasitic infection (20) and from subjects (109) infected with other helminths (Hymenolepis nana, Schistosoma mansoni, Fasciola hepatica and Ancylostoma duodenale). Hydatid cyst fluid (HCF) of camel origin was used as antigen in an ELISA format to measure total E. granulosus specific IgG antibodies and IgG subclasses. Sensitivity measurements of total IgG, and IgG1-4 were 100, 100, 79.4, 61.8 and 55.9%, respectively, whereas respective specificity reached 65.1, 97.7, 98.4, 96.1 and 83. 7%. The diagnostic value of measuring IgG1 (97.7%), as assessed by a rating index (J) for combined sensitivity and specificity, was superior to total IgG (65.1%) and IgG2-4 (77.8, 57.9 and 39.6%, respectively). These findings set the stage for field evaluation of the IgG1 assay in areas endemic with human cystic hydatidosis.

Distribution and abundance of house dust mites, Dermatophagoides spp., in different ecological localities in Esna City, Kena Governorate, Egypt.

The distribution and abundance of house dust mites, Dermatophagoides spp. were studied in July, September and November, 1995 in three different localities in Esna City, Kena Governorate, Upper Egypt. During these months, 15 houses were sampled in each locality. 87% of riverside houses were infested with mites where D. pteronyssinus dominated (80%) over D. farinae. Sixty percent of the valley houses sampled were infested, where D. farinae was dominant (66%). Densities of both Dermatophagoides spp., were considerably higher in riverside than in valley houses. Live mites were not found in the lightly infested houses sampled in the desert area (54% positive). Relative humidity, which varied in houses located in different climatic localities in Esna City, was noted to be the principal limiting factor influencing the distribution and abundance of both species. Temperature did not appear to be an important factor influencing the distribution and abundance.

Histopathological studies on detrusor muscle in schistosomiasis haematobium patients with poor bladder contractility.

The electron microscopic structure of the detrusor muscle in schistosomiasis patients with poor bladder contractility as evaluated by urodynamic measures had been compared with normal detrusor muscle from non-schistosomiasis patients. In the patients with poor bladder contractility the detrusor was formed of muscle fibers which were smaller in size, widely separated by collagen and showed degenerative changes and hyalinosis. No evidence of smooth muscle hyperplasia, mitosis or fibroblastic proliferation was seen. This pathological changes in the bladder of schistosomiasis patients may explain the cause of poor contractility.

Psammomys obesus Cretzschmar, 1828 and zoonotic cutaneous leishmaniasis in Sinai Peninsula, Egypt.

In the Middle East, the fat sand rat Psammomys obesus is the most important reservoir host of zoonotic cutaneous leishmamiasis (ZCL). It is the most incriminated host in outbreaks. Two P. obesus caught in Wadi El Gedeiret (Al Arish, North Sinai) were found naturally infected with Leishmania major as indicated by enzyme electrophoresis. In Egypt, the already known reservoir hosts are Gerbillus pyramidum I. Geoffroy St. Hilaire, 1825; Meriones crassus Sundevall, 1984 and Meriones sacramenti Thomas, 1922. The hostal role of P. obesus was discussed.

Morphological studies on Phlebotomus papatasi (Scopoli) in Riyadh City, Saudi Arabia.

In general, leishmaniasis is more or less a problem not only in Saudi Arabia but also in all countries of the Eastern Mediterranean Region. In Saudi Arabia, the most important form is zoonotic cutaneous leishmaniasis (ZCI.). It's main vector, Phlebotomus papatasi has been reported and incriminated by many authors. In this paper, the diagnostic morphology of P. papatasi as compared to other species found in Riyadh as well as the immature stages was given. This is considered as a base line data for studying the ecology and biology of P. papatasi. No doubt the best control strategy is based on complete understanding of the insect vector of ZCL.

The seasonal and daily activities of Phlebotomus papatasi in Riyadh, Saudi Arabia.

The seasonal abundance of P. papatasi was determined by monthly collection. It was found that the greatest number of sandflies occurred most commonly during the summer season with a peak in June and another one in September. Male to female ratio was 1:1.25 in Riyadh and 1:1.48 in Al Kharj. During the winter season no insect was found and then the population density started to appear again from March. The daily indoor activity of P. papatasi was in May, in the periphery of Riyadh city, showed largest amount of Phlebotomus from 10-11 pm. with sex ratio (male to female) 1:3.5 and from 4-5 am. with a sex ratio (male to female) 1:3. In the central area of Riyadh city, the highest number was from 9-11 pm. with a sex ratio (male to female) 1:3.5 also from 4-5 am. with sex ratio 1: 3. The daily outdoor activity was in June, in the peripheral area in Al Kharj city, showed the highest number from 7-9 pm. with a sex ratio (male to female) 1: 2.3 and from 5-7 am. with a sex ratio 1:1.3, while in the central area of Al Kharj, the highest number was from 7-9 pm. with a sex ratio 1: 1.1 and from 5-7 am. with a sex ratio 1: 0.9. Both the indoor and outdoor collections showed that the number of females P. papatasi were higher than number of the males, and the sandflies were more abundant in the periphery than in the central of both Riyadh and Al Kharj cities.