The role of B-cells in immunity against adult Strongyloides venezuelensis

BACKGROUND: Strongyloides venezuelensis has been used as a tool and model for strongyloidiasis research. Elimination of S. venezuelensis adult worms from mice has been particularly associated with proliferation and activation of intestinal mast cells and eosinophils. To date, the role of B-cells in the protective mechanism against adult Strongyloides infection in experimental animals has not been reported in the literature. Therefore, the present study was carried to investigate the role of B-lymphocytes in immunity against adult S. venezuelensis infection using mice with a targeted deletion of the JH locus. METHODS: JHD knockout mice with its wild-type Balb/c mice were infected by intra-duodenal implantation of adult S. venezuelensis. Fecal egg count, intestinal worm recovery, mucosal mast cells and eosinophils were counted. RESULTS: At day 11 post infection, parasites in wild-type mice stopped egg laying, while in JHD knockout mice parasites continued to excrete eggs until the end of the observation period, day 107. The higher number of parasite eggs expelled in the feces of JHD knockout infected mice was a consequence of higher worm burdens, which established in the small intestine of these animals. On the other hand worm fecundity was comparable in both groups of mice. Both B-cell-deficient mice and wild-type mice, showed an influx of mucosal mast cells and eosinophils. The absolute numbers in JHD knockout mice were lower than those seen in wild-type mice at day 11, but not to a level of significance. JHD knockout mice could not recover from infection despite the recruitment of both types of cells. CONCLUSION: Our findings highlight a role of B cells in mucosal immunity against invasion of adult S. venezuelensis and in its expulsion. Therefore, we conclude that B-cells together with mucosal mast cells and eosinophils, contribute to immunity against adult S. venezuelensis by mechanism(s) to be investigated

Toxoplasma gondii seroprevalence at a tertiary care hospital in Makkah, Saudi Arabia

Human toxoplasmosis is a cosmopolitan infection with a wide-ranging prevalence. The prevalence of Toxoplasma gondii infection is variable and depends on different eco-epidemiological factors. Both, active serological screenings and retrospective analytical methods are usually used for the investigation of toxoplasmosis seroprevalence in different populations. We conducted a two-year retrospective database search at a major tertiary care hospital to determine the prevalence of toxoplasmosis and its distribution in relation to gender and age among Makkah's population. In total, 806 females and 118 males with 33.1±9.1 years, mean age (±SD) were tested for anti-T. gondii antibodies in the last two years. Laboratory results revealed 229 seropositive subjects indicating 24.8% overall toxoplasmosis seroprevalence. Infection rate was significantly higher among male subjects (33.9%) than female subjects (23.4%). Seroprevalence increased considerably with age; from 9.7% in children less than 10 years old to 37.4% and 40.5% among adults between 40 and 49 and over 50 years, respectively. Only two anti-T. gondii IgM seropositive cases were recorded along this period, indicating possible active infection. In conclusion, overall T. gondii seropositivity rate is relatively low among Makkah's population, but moderate in adult males. Further investigations are required to determine the risk factors associated with toxoplasmosis transmission in the area. Also, adequate screening for anti-T. gondii specific antibodies are recommended, especially for immunocompromised patients and during pregnancy, in order to minimize prospective complications

Cloning, characterization and knockout of the gene encoding squalene synthase of Leishmania mexicana

SIGLEAvailable from British Library Document Supply Centre- DSC:DXN057850 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Evaluating the efficacy of a Plasmodium Species-specific Multiplex-Nest-PCR in malaria diagnosis using different DNA isolation methods

Malaria diagnosis and speciation still relies on microscopic identification in many settings. But, microscopy is tedious and lack sensitivity particularly in areas under advanced eradication programs where low-density infections are increasingly reported. Species-specific molecular techniques are highly sensitive and reliable alternatives for Plasmodium parasites detection and speciation. Nevertheless, the efficacy of molecular techniques is directly affected by the purity and quality of isolated DNA templates. A Plasmodium Species-specific Multiplex-Nested-PCR was assessed using DNA templates prepared separately by phenol-chloroform method, a DNA-precipitation commercial kit, and a chromatographic commercial kit from 126 EDTA-preserved whole blood samples. 115 samples were collected from malaria suspicious febrile patients in endemic southern region and 11 malaria positive samples from foreign and national visitors of non-endemic western region of Saudi Arabia. In total, 89 specimens were found malaria positive by at least one diagnostic method, out of which 82 (92%) were detected by microscopy. P. Multiplex-N-PCR revealed 89 (100%), 77 (86.5%), and 85 (95.5%) positive samples using DNA templates extracted by the chromatographic kit, the DNA-precipitation kit, and phenol-chloroform standard method, respectively. P. falciparum parasites were detected in 86 samples and P. vivax in three samples from foreign visitors. Thus, P. Multiplex-N-PCR applied to DNA templates isolated by chromatographic method achieved the highest sensitivity and was particularly useful for submicroscopic malaria cases in the endemic area where intensive elimination efforts are being deployed

Low-Area and Low-Power VLSI Architectures for Long Short-Term Memory Networks

Long short-term memory (LSTM) networks are extensively used in various sequential learning tasks, including speech recognition. Their significance in real-world applications has prompted the demand for cost-effective and power-efficient designs. This paper introduces LSTM architectures based on distributed arithmetic (DA), utilizing circulant and block-circulant matrix-vector multiplications (MVMs) for network compression. The quantized weights-oriented approach for training circulant and block-circulant matrices is considered. By formulating fixed-point circulant/block-circulant MVMs, we explore the impact of kernel size on accuracy. Our DA-based approach employs shared full and partial methods of add-store/store-add followed by a select unit to realize an MVM. It is then coupled with a multi-partial strategy to reduce complexity for larger kernel sizes. Further complexity reduction is achieved by optimizing decoders of multiple select units. Pipelining in add-store enhances speed at the expense of a few pipelined registers. The results of the field-programmable gate array showcase the superiority of our proposed architectures based on the partial store-add method, delivering reductions of 98.71% in DSP slices, 33.59% in slice look-up tables, 13.43% in flip-flops, and 29.76% in power compared to the state-of-the-art.</p

Subtyping of Blastocystis sp. isolated from symptomatic and asymptomatic individuals in Makkah, Saudi Arabia

Abstract Background Blastocystis is a group of cosmopolitan gastrointestinal parasite of humans and a wide variety of animals. These anaerobic protozoans include more than 17 specific small-subunit ribosomal RNA subtypes, of which nine are found in humans with a variable geographical distribution. Until now, no study has described the Blastocystis subtypes present in Saudi Arabia. Methods In total, 1,262 faecal samples were collected from patients with gastrointestinal complaints and asymptomatic individuals visiting two major hospitals. All samples were analysed by F1/R1 diagnostic PCR, microscopy and culture methods. The subtypes of Blastocystis sp. isolates were determined by the sequenced-tagged site (STS)-based method. Results One-hundred-thirty-three positive cases were detected by F1/R1 diagnostic PCR, of which 122 were also positive by the culture method and 83 by direct microscopy. The sensitivities of direct microscopy and the culture method were 62% and 92%, respectively. Subtype (ST3) was the most prevalent (80.5%), followed by ST1 (14.5%) and ST2 (5%). ST4, ST5, ST6 and ST7 were not detected in this study. ST3 infections were significantly predominant (P < 0.05) among symptomatic patients. Conclusions To our knowledge, this study provides the first run-through information on Blastocystis sp. epidemiology in Makkah city, revealing a rather moderate prevalence of 10.5% and the presence of three subtypes, ST1, ST2, and ST3. ST3 was the most predominant, particularly among symptomatic patients