Study of the gut microbiome in Egyptian patients with active ulcerative colitis

INTRODUCTION AND AIM

Ulcerative colitis (UC) is characterized by chronic, uncontrolled inflammation of the intestinal mucosa. Gut microbiota dysbiosis was reported to be a factor in intestinal inflammation. The aim of the present study was to study changes in the gut microbiome in Egyptian patients with active UC.

MATERIALS AND METHODS

In this cross-sectional study, the gut bacterial microbiome of 21 UC patients and 20 control subjects was analyzed using the quantitative SYBR Green real-time PCR technique, targeting the 16S rRNA gene of selected bacterial phyla/genera and/or species.

RESULTS

UC patients showed marked dysbiosis evidenced by a significant decrease in the Firmicutes and F. prausnitzii anti-inflammatory bacteria. The Firmicutes/Bacteroidetes ratio was also lower in the UC cases (1.65), compared with the healthy controls (2.93). In addition, the UC cases showed a statistically significant decrease in Ruminococcus, compared with the control group. However, there were no statistically significant differences between UC patients and the controls, regarding A. muciniphila, Bifidobacterium, Lactobacillus, Bacteroides, and Prevotella. One UC case was positive for the pathogenic bacterium, Clostridioides difficile, with low relative abundance.

CONCLUSION

The current study showed differences in the gut microbiome of UC patients, compared with healthy controls. This may help in identifying the gut microbiome and specific bacterial changes that can be targeted for treatment of UC.

Red Cell Alloimmunization in Repeatedly Transfused Sudanese Patients with leukemia in Northern Sudan

BACKGROUND

Leukemia frequently causes anemia; thus patients need products containing normal blood or RBCs for treatment. Anti-red blood cell alloantibody formation is still a critical challenge in transfusion.

OBJECTIVES

The current study aimed to investigate RBC alloantibodies in Sudanese leukemia patients who receive multiple blood transfusions at the cancer center in Dongola and Maroyee, Northern Sudan.

MATERIALS AND METHODS

At the Northern State oncology center in Dongola and Maroyee, Sudan, an across-sectional descriptive study design was used. In this study, 100 leukemic patients who had received blood transfusions three times or more were enrolled. From each participant, Peripheral blood was drawn in amounts of 3 ml in EDTA vacutainer tubes for ABO blood group and Rh factor testing and 3 ml in non-additive containers for antibody screening and Alloantibody identification. All individuals' ABO blood groups and Rh factors were determined using the slide method. Indirect Coombs test apply to detect alloantibodies by Polly Specific antihuman globulin reagents using tube method techniques. Alloantibody identification was performed by DiaMed-ID microtyping system.

RESULTS

Incidence of alloimmunization was 11%, with 11 alloantibodies found in 11 patients. The most common alloantibody was kell (36.4%), followed by Lea (27.2%; 3/11), then P (18.2%; 2/11) and M (18.2%; 2/11).

CONCLUSION

Anti kell antibody was the most prevalent alloantibody among leukemic patients with multiple transfusions.

Can granulocyte colony stimulating factor (G-CSF) ameliorate acetaminophen-induced hepatotoxicity?

Acetaminophen (APAP) is often used as an antipyretic and analgesic agent. Overdose hepatotoxicity, which often results in liver cell failure and liver transplantation, is a severe complication of APAP usage. To save the liver and save lives from acute liver damage caused by APAP, the search for new strategies for liver defense is important. Wistar rats have been used for the induction of APAP hepatotoxicity. Elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were evaluated for liver toxicity. In addition, the levels of hepatic tissue oxidative markers such as malondialdehyde (MDA), nitric oxide (NO) increased while glutathione (GSH) was depleted and catalase (CAT) activity was curtailed. The biochemical findings were consistent with the changes in histology that suggested liver damage and inflammation. Treated rats with N-acetylcysteine (N-AC) and granulocyte colony stimulating factor (G-CSF) showed a decrease in serum levels of ALT, AST and LDH, while the level of ALP in the G-CSF group was still high. After administration of APAP, treatment with N-AC or G-CSF substantially reduced the level of MDA and NO while maintaining the GSH content and CAT activity. Treatment with N-AC and G-CSF after administration of APAP has also attenuated inflammation and hepatocytes necrosis. The results of this study showed that G-CSF could be viewed as an alternative hepatoprotective agent against APAP-induced acute liver injury compared to N-AC.

The interplay between vitamin D and COVID-19: protective or bystander?

The world is currently facing the COVID-19 pandemic, caused by the novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Due to a lack of specific treatment and prophylaxis, protective health measures that can reduce infection severity and COVID-19 mortality are urgently required. Clinical and epidemiological studies have shown that vitamin D deficiency can be linked to an increased risk of viral infection, including COVID-19. Therefore, in this review, we looked at various possible roles of vitamin D in reducing the risk of COVID-19 infection and severity. We describe in this article that individuals at high risk of vitamin D deficiency should consider taking vitamin D supplements to keep optimal concentrations. Moreover, we discuss different possible mechanisms by which vitamin D can efficiently reduce the risk of infections through modulation of innate and adaptive immunity against various types of infections. It is advisable to perform further studies addressing the observed influence of vitamin D levels to reduce the risk of COVID-19 infection and mortality.

Visual adaptability and retinal characterization of the Egyptian fruit bat (Rousettus aegyptiacus, Pteropodidae): New insights into photoreceptors spatial distribution and melanosomal activity

Our study was conducted to characterize the retinal structure of the Egyptian fruit bat, Rousettus aegyptiacus to determine the distribution of photoreceptors and melanosomal populations in various retinal zones. Also, we paid attention to the specific structural and functional adaptations related to their nocturnal habits. We analyzed the retinae of 12 adult male Egyptian fruit bats using morphometrical, histological, ultrastructural, and immunoblotting standard techniques. Histological findings revealed that the retinal cells have variations in geometrical architecture and different retinal thickness together with their corresponding layers bearing specific choroidal papillae projecting towards the inner retina. Immunoblotting and ultrastructure results showed that the microstructure of the retina conforms to that pattern found in mammalian species. The retinal photoreceptors are rod-dominant; alternatively, possess two spectral types of cones: SWS and LW/MWS cones as evidence for the basis for dichromatic vision. In addition, the outer retina showed densely-distributed melanin granules with a significant increase in the number of pigment epithelium cells in the eccentric retina. Furthermore, the asymmetric distribution among the retinal quadrants for the visual pigments of both rods and cones coinciding with neuronal cells such as bipolar and ganglion cells confers instructive information about their visual perception and orientation. In conclusion, our findings indicate that R. aegyptiacus efficiently discriminates colors with complex visual adaptations to mediate increased visual acuity coopted for the nocturnal niches.

Streptococcal protective antigens (Spa): a new family of type-specific proteins of group A streptococci

Previous studies in our laboratory described a new group A streptococcal protective antigen (Spa) in type 18 streptococci that was distinct from the type 18 M protein. This study was undertaken to identify additional serotypes of group A streptococci that express Spa proteins. PCR techniques were used to identify and clone a new spa gene from type 36 streptococci. The 5' sequence of spa36 was highly variable compared to spa18, while the 3' sequence was conserved. Antisera against Spa36 opsonized type 36 streptococci but not type 18 streptococci, indicating that the opsonic Spa epitopes were type-specific. Antisera against the conserved carboxy-terminal half of Spa18 were used to identify Spa or Spa-like proteins expressed on the surface of 25 of 70 different serotypes of GAS. Spa proteins may represent a new family of type-specific surface antigens that function in concert with M proteins to elicit protective immune responses.

The need for revised standards for skinfold thickness in infancy

Skinfold standards provide a useful indication of subcutaneous fat. To evaluate skinfold thickness of 252 Cambridge infants over the first 2 years of age, SD scores relative to the Tanner standards were calculated, taking account of skewness in the standards. Cambridge SD scores were low, varying according to age from -1.2 to -1.8 for triceps and -0.6 to -1.2 for subscapular skinfolds. The Tanner skinfold standards were last revised 30 years ago, at a time of high prevalence of infantile obesity, and the present and other studies indicate that infants are now thinner. There is a need for new skinfold standards to reflect this change. Since the Cambridge infants contributed to the recent British height and weight references, it is suggested that their skinfold measurements could also serve as reference points.

Expression of the superantigen Mycoplasma arthritidis mitogen in Escherichia coli and characterization of the recombinant protein

Mycoplasma arthritidis mitogen (MAM), is a soluble protein with classical superantigenic properties and is produced by an organism that causes an acute and chronic proliferative arthritis. Unfortunately, the process of obtaining purified MAM from M. arthritidis culture supernatants is extremely time-consuming and costly, and very little material is recovered. Thus, our laboratory has expressed MAM in Escherichia coli by using a protein fusion expression system. The construction and expression of recombinant MAM (rMAM), as well as a comparison of the biological properties of rMAM to those of native MAM, are discussed. Briefly, conversion of the three UGA codons to UGG codons was required to obtain full-length expression and mitogenic activity of rMAM. Antisera to native MAM recognized both rMAM and the fusion protein. The T-cell receptor Vbeta and major histocompatibility complex class II receptor usages by rMAM and the fusion protein were identical to that of native MAM. In addition, the ability to induce suppression and form the superantigen bridge could also be demonstrated with rMAM. Importantly, dose-response experiments indicated that homogeneous native MAM and rMAM were of equal potency. Thus, MAM has been successfully expressed in E. coli, thereby creating a viable alternative to native MAM.

Allelic polymorphisms at the H-2A and HLA-DQ loci influence the response of murine lymphocytes to the Mycoplasma arthritidis superantigen MAM

Mycoplasma arthritidis, an agent of rodent arthritis, produces a potent superantigen (SAg), MAM. Previous work established that MAM is presented to T cells by murine H-2E or the homologous human HLA-DR molecules and that lymphocytes lacking a functional H-2E molecule fail to respond to MAM. Recently, more potent and purified preparations of MAM of known protein content have become available. This enabled us to more effectively compare the response of MAM with that of other SAgs by using lymphocytes from mice whose cells express different H-2A and HLA-DQ molecules. Here we demonstrate that cells from some H-2E-negative mouse strains respond to higher concentrations of MAM. By use of inbred, congenic, and recombinant mice, we show that these differences are, in fact, exercised at the level of the major histocompatibility complex (MHC) and that allelic polymorphisms at H-2A influence reactivity to MAM. In addition, polymorphisms at HLA-DQ, the human homolog of H-2A, also influence responsiveness to MAM. Cells expressing DQw6 (HLA-DQA1*0103 and DQBI*0601 chains) gave much higher responses to MAM than did cells expressing DQw8 (DQA1*0301 and DQB1*0302 chains). In fact, responses of lymphocytes expressing DQB1*0601 chains homozygously were as high as those observed for cells expressing a functional H-2E molecule. Murine lymphocytes responded less well to staphylococcal enterotoxin B (SEB) and SEA, but mouse cells expressing human MHC molecules gave much higher responses. The patterns of reactivity observed with cells expressing the various murine and human alleles differed for MAM, SEB, and SEA, suggesting that each of these SAgs interacts with different regions or residues on MHC molecules. It has been hypothesized that SAgs might play a role in susceptibility to autoimmune disease. Allelic polymorphisms at MHC loci might therefore influence susceptibility to autoimmune disease by affecting immunoreactivity to specific superantigens.

Genomic composition and allelic polymorphisms influence V beta usage by the Mycoplasma arthritidis superantigen

The Mycoplasma arthritidis superantigen (MAM) is produced by an organism that causes systemic disease in rodents leading to chronic proliferative arthritis. MAM is a typical superantigen that requires presentation to T cells by MHC molecules without processing and T cell recognition of MAM occurs through the V beta chains of the TCR. Several major findings are presented here. First, different MAM-MHC class II isotype complexes may engage different sets of V beta TCR. Thus, activation of V beta 6- and V beta 8.3-bearing T cells is more dependent upon the I-E molecule of the murine H-2 MHC than is activation of cells bearing the V beta 5.1, 8.1, and 8.2 TCR. Secondly, both genomic composition and allelic polymorphisms at the V beta chain segment of the TCR exert profound effects upon the pattern of V beta that are used by MAM. Thus, in V beta b haplotype mice, MAM engages V beta 5.1, 6, and the V beta 8 family of TCR whereas in V beta a (C57BR) and V beta c (RIIIS) haplotype mice that lack various combinations of these V beta, activation of cells bearing V beta 1, 3.1, 7, and 16 can be demonstrated. These differences in V beta usage by MAM appear to be caused by both differences in the avidity of MAM for the various V beta s and to structural allelic polymorphisms in these V beta. Clonal expansion of specific V beta in vivo after injection of MAM is also dependent upon the genomic composition of the mice, because expansion of the V beta 8 TCR seen in V beta b haplotype mice (B10.RIII) whereas marked expansion of V beta 6 is seen in V beta a mice (C57BR). In as much as these TCR have been implicated in a number of experimental autoimmune diseases, MAM may represent an ideal model to evaluate the role of superantigens in the triggering of autoimmune disease.

Genomic composition and allelic polymorphisms influence V beta usage by the Mycoplasma arthritidis superantigen

The Mycoplasma arthritidis superantigen (MAM) is produced by an organism that causes systemic disease in rodents leading to chronic proliferative arthritis. MAM is a typical superantigen that requires presentation to T cells by MHC molecules without processing and T cell recognition of MAM occurs through the V beta chains of the TCR. Several major findings are presented here. First, different MAM-MHC class II isotype complexes may engage different sets of V beta TCR. Thus, activation of V beta 6- and V beta 8.3-bearing T cells is more dependent upon the I-E molecule of the murine H-2 MHC than is activation of cells bearing the V beta 5.1, 8.1, and 8.2 TCR. Secondly, both genomic composition and allelic polymorphisms at the V beta chain segment of the TCR exert profound effects upon the pattern of V beta that are used by MAM. Thus, in V beta b haplotype mice, MAM engages V beta 5.1, 6, and the V beta 8 family of TCR whereas in V beta a (C57BR) and V beta c (RIIIS) haplotype mice that lack various combinations of these V beta, activation of cells bearing V beta 1, 3.1, 7, and 16 can be demonstrated. These differences in V beta usage by MAM appear to be caused by both differences in the avidity of MAM for the various V beta s and to structural allelic polymorphisms in these V beta. Clonal expansion of specific V beta in vivo after injection of MAM is also dependent upon the genomic composition of the mice, because expansion of the V beta 8 TCR seen in V beta b haplotype mice (B10.RIII) whereas marked expansion of V beta 6 is seen in V beta a mice (C57BR). In as much as these TCR have been implicated in a number of experimental autoimmune diseases, MAM may represent an ideal model to evaluate the role of superantigens in the triggering of autoimmune disease.

Weaning practices in the United Kingdom and variations in anthropometric development

The influence of different weaning practices on the dietary energy intake and growth of Cambridge infants has been investigated. Bottle fed children were in general given solid foods sooner, 10.6 weeks for boys and 13.9 weeks with girls: among breast-fed babies the average age was 14.9 weeks in the case of boys and 17.4 weeks for girls. All four groups of children exhibited different growth patterns from those of the NCHS and Tanner reference curves. Over the first three months both boys and girls exhibited a faster velocity of growth in weight, length and weight-for-length. After this time, however, growth velocity was slower than that of the reference children particularly among breast-fed boys who were not given solids until after 16 weeks. For most of infancy triceps and subscapular skinfold thicknesses remained around the 10th centile of the corresponding Tanner reference children, although again the babies weaned later had the lower values. Bottle-fed infants had growth patterns similar to those of the earlier weaned breast-fed babies for all parameters. It is concluded that babies grow differently now that infant feeding patterns have changed.