The etiology of upper gastrointestinal bleeding (UGIB) varies by age, from newborns to adolescents, with some of the causes overlapping between age groups. While particular causes such as vitamin K deficiency and cow’s milk protein allergy are limited to specific age groups, occurring only in neonates and infants, others such as erosive esophagitis and gastritis may be identified at all ages. Furthermore, the incidence of UGIB is variable throughout the world and in different hospital settings. In North America and Europe, most UGIBs are non-variceal, associated with erosive esophagitis, gastritis, and gastric and duodenal ulcers. In recent years, the most common causes in some Middle Eastern and Far Eastern countries are becoming similar to those in Western countries. However, variceal bleeding still predominates in certain parts of the world, especially in South Asia. The most severe hemorrhage arises from variceal bleeding, peptic ulceration, and disseminated intravascular coagulation. Hematemesis is a credible indicator of a UGI source of bleeding in the majority of patients. Being familiar with the most likely UGIB causes in specific ages and geographic areas is especially important for adequate orientation in clinical settings, the use of proper diagnostic tests, and rapid initiation of the therapy. The fundamental approach to the management of UGIB includes an immediate assessment of severity, detecting possible causes, and providing hemodynamic stability, followed by early endoscopy. Unusual UGIB causes must always be considered when establishing a diagnosis in the pediatric population because some of them are unique to children. Endoscopic techniques are of significant diagnostic value, and combined with medicaments, may be used for the management of acute bleeding. Finally, surgical treatment is reserved for the most severe bleeding.

Recent scientific data recognize the B7-H3 checkpoint molecule as a potential target for immunotherapy of pediatric solid tumors (PSTs). B7-H3 is highly expressed in extracranial PSTs such as neuroblastoma, rhabdomyosarcoma, nephroblastoma, osteosarcoma, and Ewing sarcoma, whereas its expression is absent or very low in normal tissues and organs. The influence of B7-H3 on the biological behavior of malignant solid neoplasms of childhood is expressed through different molecular mechanisms, including stimulation of immune evasion and tumor invasion, and cell-cycle disruption. It has been shown that B7-H3 knockdown decreased tumor cell proliferation and migration, suppressed tumor growth, and enhanced anti-tumor immune response in some pediatric solid cancers. Antibody-drug conjugates targeting B7-H3 exhibited profound anti-tumor effects against preclinical models of pediatric solid malignancies. Moreover, B7-H3-targeting chimeric antigen receptor (CAR)-T cells demonstrated significant in vivo activity against different xenograft models of neuroblastoma, Ewing sarcoma, and osteosarcoma. Finally, clinical studies demonstrated the potent anti-tumor activity of B7-H3-targeting antibody-radioimmunoconjugates in metastatic neuroblastoma. This review summarizes the established data from various PST-related studies, including in vitro, in vivo, and clinical research, and explains all the benefits and potential obstacles of targeting B7-H3 by novel immunotherapeutic agents designed to treat malignant extracranial solid tumors of childhood.

B7 homologue 3 as a prognostic biomarker and potential therapeutic target in gastrointestinal tumors

Despite advances in cancer treatment, pancreatic cancer (PC) remains a disease with high mortality rates and poor survival outcomes. The B7 homolog 3 (B7-H3) checkpoint molecule is overexpressed among many malignant tumors, including PC, with low or absent expression in healthy tissues. By modulating various immunological and nonimmunological molecular mechanisms, B7-H3 may influence the progression of PC. However, the impact of B7-H3 on the survival of patients with PC remains a subject of debate. Still, most available scientific data recognize this molecule as a suppressive factor to antitumor immunity in PC. Furthermore, it has been demonstrated that B7-H3 stimulates the migration, invasion, and metastasis of PC cells, and enhances resistance to chemotherapy. In preclinical models of PC, B7-H3-targeting monoclonal antibodies have exerted profound antitumor effects by increasing natural killer cell-mediated antibody-dependent cellular cytotoxicity and delivering radioisotopes and cytotoxic drugs to the tumor site. Finally, PC treatment with B7-H3-targeting antibody-drug conjugates and chimeric antigen receptor T cells is being tested in clinical studies. This review provides a comprehensive analysis of all PC-related studies in the context of B7-H3 and points to deficiencies in the current data that should be overcome by future research.

A pyogenic liver abscess (PLA) represents a pus-filled cavity within the liver parenchyma caused by the invasion and multiplication of bacteria. The most common offender isolated from the PLA in children is Staphylococcus aureus. Abiotrophia defectiva is a Gram-positive pleomorphic bacterium, commonly found in the oral cavity, intestinal, and genitourinary mucosa as part of the normal microbiota. It has been proven to be an etiological factor in various infections, but rarely in cases of PLA. The case presented here is, to the best of our knowledge, the first pediatric case of PLA caused by A. defectiva. A 13-year-old Caucasian boy presented with a two-day history of abdominal pain, fever up to 40 °C, and polyuria. Contrast-enhanced computed tomography (CT) scan revealed a single, multiloculated liver lesion, suggestive of a liver abscess. The boy had sustained a bicycle handlebar injury to his upper abdomen 3 weeks before the symptoms appeared and had been completely asymptomatic until 2 days before admission. He was successfully treated with antibiotic therapy and open surgical drainage. A. defectiva was isolated from the abscess material. Histopathology report described the lesion as a chronic PLA. A. defectiva is a highly uncommon cause of liver abscess in children. In such cases, various predisposing factors should be considered, including antecedent blunt abdominal trauma.

Secondary peritonitis (SP) remains a major clinical challenge due to its high complication rates and it often results in sepsis and multi-organ dysfunction. This study investigated the association between four nitric oxide synthase (NOS) single-nucleotide polymorphisms (SNPs)—NOS3 c.-786T>C (rs2070744), NOS3 c.894G>T (rs1799983), NOS3 27 bp variable number tandem repeat (VNTR) (rs61722009), and NOS2 (rs2297518)—and sepsis-related complications in 202 patients with SP. Demographic and baseline clinical characteristics, Acute Physiology and Chronic Health Evaluation (APACHE) II scores, Mannheim Peritonitis Index, and complications (multiple organ dysfunction syndrome (MODS), multiple organ failure (MOF), acute respiratory distress syndrome (ARDS), and sepsis) were analyzed for associations with the NOS gene variants. Haplotype analysis was also performed. No SNP showed an association with in-hospital mortality. However, the NOS3 c.-786T>C TT genotype was significantly associated with an increased risk of MOF (p = 0.008), and remained independently associated after multivariate adjustment (p_MOF = 0.006). The T4bG haplotype was significantly more frequent among patients with MODS (p = 0.026), MOF (p = 0.048), and sepsis (p = 0.018). These findings suggest that NOS gene variants, particularly NOS3 c.-786T>C and the T4bG haplotype, may potentially serve as biomarkers for risk stratification in critically ill patients.