In Silico and in Vitro Screening for P-Glycoprotein Interaction with Tenofovir, Darunavir, and Dapivirine: An Antiretroviral Drug Combination for Topical Prevention of Colorectal HIV Transmission.

The aim of the study was to use in silico and in vitro techniques to evaluate whether a triple formulation of antiretroviral drugs (tenofovir, darunavir, and dapivirine) interacted with P-glycoprotein (P-gp) or exhibited any other permeability-altering drug-drug interactions in the colorectal mucosa. Potential drug interactions with P-gp were screened initially using molecular docking, followed by molecular dynamics simulations to analyze the identified drug-transporter interaction more mechanistically. The transport of tenofovir, darunavir, and dapivirine was investigated in the Caco-2 cell models and colorectal tissue, and their apparent permeability coefficient (Papp), efflux ratio (ER), and the effect of transporter inhibitors were evaluated. In silico, dapivirine and darunavir showed strong affinity for P-gp with similar free energy of binding; dapivirine exhibiting a ΔGPB value -38.24 kcal/mol, darunavir a ΔGPB value -36.84 kcal/mol. The rank order of permeability of the compounds in vitro was tenofovir < darunavir < dapivirine. The Papp for tenofovir in Caco-2 cell monolayers was 0.10 ± 0.02 × 10-6 cm/s, ER = 1. For dapivirine, Papp was 32.2 ± 3.7 × 10-6 cm/s, but the ER = 1.3 was lower than anticipated based on the in silico findings. Neither tenofovir nor dapivirine transport was influenced by P-gp inhibitors. The absorptive permeability of darunavir (Papp = 6.4 ± 0.9 × 10-6 cm/s) was concentration dependent with ER = 6.3, which was reduced by verapamil to 1.2. Administration of the drugs in combination did not alter their permeability compared to administration as single agents. In conclusion, in silico modeling, cell culture, and tissue-based assays showed that tenofovir does not interact with P-gp and is poorly permeable, consistent with a paracellular transport mechanism. In silico modeling predicted that darunavir and dapivirine were P-gp substrates, but only darunavir showed P-gp-dependent permeability in the biological models, illustrating that in silico modeling requires experimental validation. When administered in combination, the disposition of the proposed triple-therapy antiretroviral drugs in the colorectal mucosa will depend on their distinctly different permeability, but was not interdependent.

Opportunistic cytomegalovirus infection causing colonic perforation in a patient with systemic lupus erythematosus.

We present the case of a 58-year-old woman with a long-standing history of systemic lupus erythematosus (SLE) who developed a cytomegalovirus (CMV) infection with colonic perforation and subsequent purulent peritonitis whilst using combined immunosuppressive therapy. The pathogenesis and the clinical presentation of this unique case is discussed in detail. Opportunistic infection should always be kept in mind in SLE patients presenting with fever. Viral serology should be routinely performed in these patients, especially when immunosuppressive therapy is given, to avoid delay in instituting adequate management and therapy.

Primary classic Hodgkin lymphoma of the ileum and Epstein-Barr virus mucocutaneous ulcer of the colon: two entities compared.

Primary classic Hodgkin lymphoma of the gastrointestinal tract represents a rare occurrence. A full patient's work-up is essential in order to exclude a secondary intestinal involvement. Histologically Epstein-Barr virus mucocutaneous ulcer closely resembles Hodgkin lymphoma. The differential diagnosis between these two entities is relevant, since both the therapeutic approach and the clinical behavior are different. Herein, we describe a case of primary classic Hodgkin lymphoma arising in the ileum and a case of Epstein-Barr virus mucocutaneous ulcer of the colon, focusing on the main clinicopathological differences.

Manifestación gastrointestinal exclusiva como forma de presentación de infección por coronavirus (COVID-19) / Exclusive gastrointestinal signs as a form of presentation of coronavirus (covid-19) infection

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Incidence of rotavirus diarrhea and intussusception in Hong Kong using standardized hospital discharge data.

Incidence for rotavirus and intussusception was estimated from standardized discharge data for all Hong Kong government hospitals (1997 to 1999). Intussusception incidence in infants (78 to 100 of 100,000) was relatively high. The distinct winter seasonality of rotavirus was not evident for intussusception. During the first 5 years of life an estimated 1 child of 28 is admitted with rotavirus infection (4% of all medical admissions).

Post-transplant lymphoproliferative disorder after autologous peripheral stem cell transplantation in a pediatric patient.

Post-transplant lymphoproliferative disorder (PTLD) is a complication of allogeneic bone marrow transplantation (BMT). Rare cases of PTLD after autologous BMT have been reported only in adults. This case report is the first to describe PTLD in a pediatric patient after autologous peripheral stem cell transplantation (PSCT). This 2-year-old male with stage IV neuroblastoma underwent autologous PSCT. The post-PSCT course was complicated by fever with hematochezia and a lung mass. On day 94 post PSCT, colonoscopy revealed an ulcer due to a PTLD, monomorphic type, B cell phenotype, associated with Epstein-Barr virus. Fine needle aspiration identified the lung mass as neuroblastoma. PTLD can occur in pediatric autologous PSCT recipients, and may occur more frequently in autologous grafts manipulated by T cell depletion or CD34+ cell selection.

Elucidation of cytomegalovirus disease recurrence in an HIV-1-positive patient.

BACKGROUND: Cytomegalovirus (CMV) is responsible for the most common opportunistic viral infection in patients with acquired immunodeficiency syndrome (AIDS). The colon is a common site for CMV infection in patients positive for the human immunodeficiency virus (HIV). The clinical diagnosis of CMV infection is based on the characteristic endoscopic appearance of extensive ulceration of the gastric mucosa. METHODS: A 54-year-old HIV-positive man visited our hospital because of high fever. The patient presented with diarrhea, and colonoscopy was performed. Ganciclovir was administered, with a good clinical response. However, the patient complained of the same symptoms again 6 months later. Nested polymerase chain reaction (PCR) was performed on all the patient's samples to detect CMV, followed by sequencing of the UL97 gene for CMV resistance detection. RESULTS: The PCR tests for Legionella, Chlamydia pneumoniae, Pneumocystis carinii, and Aspergillus were negative. DNA preparations from biopsy specimens of areas of colon ulceration were positive for CMV. Six months after treating the colon ulcerations, the PCR for CMV was positive, and the possible emergence of CMV mutants conferring ganciclovir resistance was examined. Direct sequencing of the PCR products revealed the known V594 mutation in the UL97 gene predisposing for ganciclovir resistance as well as the polymorphisms (579, GGC-->GGT) and (598, GGT-->GGC) in all samples tested. CONCLUSIONS: In summary, molecular biology methods can be used for early detection of CMV in characteristic colonic lesions in HIV-1-positive patients. Furthermore, detection of mutant strains resistant to antiviral drugs as well as polymorphisms elucidate the natural history of the infection.

A case of toxic megacolon in ulcerative colitis associated with cytomegalovirus infection.

Cytomegalovirus (CMV) infection, which has been shown to complicate the course of ulcerative colitis (UC), has been implicated as a possible etiologic factor in the exacerbation of UC, especially in toxic megacolon. However, CMV infection in patients with UC accompanied by toxic megacolon has rarely been reported. Here we report a case of CMV infection of the colon accompanied by toxic megacolon occurring in UC. A 38-year-old woman had been treated with intravenous hydrocortisone, rectal steroid, and central venous alimentation for 6 weeks under the diagnosis of UC. She was transferred to Akita University Hospital because of increasing bloody diarrhea and abdominal pain. Toxic megacolon was identified by examinations on admission, and she underwent a total colectomy. Examination of the surgical specimen showed severe inflammation of the colon. Microscopically, cytomegalic inclusions were observed in and around the endothelial cells in the inflamed submucosal layer. It can be assumed that CMV infection was a secondary, opportunistic invader superimposed on UC, and that it played an important role in altering the clinical course of the patient.

Post-kidney transplant large bowel lymphoproliferative disorder.

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation. The gastrointestinal (GI) tract is a common site involved, but non-specific signs and symptoms often delay the diagnosis. We report a case of EBV-associated GI-PTLD in a 68-year-old kidney transplant patient who received the kidney ten months earlier. He presented with chronic diarrhea and developed massive pneumo-peritoneum secondary to multiple colonic perforations.

Brote severo de enfermedad inflamatoria intestinal vs. rara manifestación de úlcera mucocutánea Epstein-Barr positiva. Informe de caso / No disponible

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Cytomegalovirus: a cause of colonic stricture in a premature infant.

A 27-week-old infant developed symptoms of bowel obstruction when full enteral feeds were started. Laparotomy revealed strictures in the ascending and proximal transverse colon. Right hemicolectomy was performed. Histological examination of the resected large bowel demonstrated the presence of Cytomegalovirus inclusion bodies. Cytomegalovirus infections of the gut are extremely rare in neonates. This case report alerts neonatologists and microbiologists to consider Cytomegalovirus infection as a possible cause of bowel obstruction and necrotising enterocolitis like symptoms.