Clarithromycin is a macrolide antibiotic widely used for eradication ofHelicobacter pyloriinfection, and thus resistance to this antibiotic is a major cause of treatment failure. Here, we present the results of a retrospective observational study of clarithromycin resistance (Cla-res) in 4744H. pylori-infected patients from Central Hungary. We use immunohistochemistry and fluorescence in situ hybridization on fixed gastric tissue samples to determineH. pyloriinfection and to infer Cla-res status, respectively. We correlate this information with macrolide dispensing data for the same patients (available through a prescription database) and develop a mathematical model of the population dynamics of Cla-resH. pyloriinfections. Cla-res is found in 5.5% of macrolide-naive patients (primary Cla-res), with no significant sex difference. The model predicts that this primary Cla-res originates from transmission of resistant bacteria in 98.7% of cases, and derives from spontaneous mutations in the other 1.3%. We find an age-dependent preponderance of female patients among secondary (macrolide-exposed) clarithromycin-resistant infections, predominantly associated with prior use of macrolides for non-eradication purposes. Our results shed light into the sources of primary resistant cases, and indicate that the growth rate of Cla-res prevalence would likely decrease if macrolides were no longer used for purposes other thanH. pylorieradication.

Background: Clarithromycin (Cla) heteroresistance of Helicobacter pylori (H pylori) infections is commonly assessed by comparing the resistance status of antrum and corpus biopsy samples and by demonstrating the discrepancy between them (interniche heteroresistance). However, fluorescence in situ hybridization (FISH) technique is capable of showing the synchronous presence of susceptible and resistant bacteria (intraniche heteroresistance), enabling the detection of heteroresistant H pylori populations within one biopsy sample.Materials and Methods: Antrum and corpus biopsy specimens of 305 H pylori‐infected patients were investigated with an rRNA‐targeted Cla‐resistance FISH test. Anamnestic data were collected from the institutional electronic register. Prevalence rates of susceptible, homo‐ and heteroresistant cases were correlated with the anamnestic and clinicopathological data.Results: Overall Cla‐resistance rate was 23.9% (73 cases), consisting of 35 (11.5%) homoresistant and 38 (12.5%) heteroresistant cases. Thirty‐five patients had at least one biopsy site where susceptible and resistant bacteria were present simultaneously. From this subset, 20 cases demonstrated intraniche heteroresistance on both sites. Prior Cla‐based eradication attempts were more frequent in homoresistant than in susceptible and heteroresistant cases (P < .001, P < .001, respectively). Cla‐containing therapy eradicated heteroresistant infections at a significantly lower rate in comparison with susceptible cases (P = .0112), but more effectively than homoresistants (P = .0393).Conclusions: The most frequent type of Cla‐heteroresistance is the coexistence of susceptible and resistant H pylori bacteria in the same location (intraniche heteroresistance). A previous Cla‐based eradication attempt predisposes patients to homoresistant infection. Heteroresistance is characterized by a non‐eradication‐related background and intermediate characteristics in many respects when compared to susceptible and homoresistant cases.

Protein expression is a primary area of interest for routine histological diagnostics and tissue-based research projects, but the limitations of its post-mortem applicability remain largely unclear. On the other hand, tissue specimens obtained during autopsies can provide unique insight into advanced disease states, especially in cancer research. Therefore, we aimed to identify the maximum post-mortem interval (PMI) which is still suitable for characterizing protein expression patterns, to explore organ-specific differences in protein degradation, and to investigate whether certain proteins follow specific degradation kinetics. Therefore, the proteome of human tissue samples obtained during routine autopsies of deceased patients with accurate PMI (6, 12, 18, 24, 48, 72, 96 h) and without specific diseases that significantly affect tissue preservation, from lungs, kidneys and livers, was analyzed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). For the kidney and liver, significant protein degradation became apparent at 48 h. For the lung, the proteome composition was rather static for up to 48 h and substantial protein degradation was detected only at 72 h suggesting that degradation kinetics appear to be organ specific. More detailed analyses suggested that proteins with similar post-mortem kinetics are not primarily shared in their biological functions. The overrepresentation of protein families with analogous structural motifs in the kidney indicates that structural features may be a common factor in determining similar postmortem stability. Our study demonstrates that a longer post-mortem period may have a significant impact on proteome composition, but sampling within 24 h may be appropriate, as degradation is within acceptable limits even in organs with faster autolysis.

The prognostic value of histological phenomena tumor budding (TB) and poorly differentiated clusters (PDCs) have been less studied in gastric cancer (GAC) and the data provided so far are controversial. In our study, 290 surgically resected GAC cases were evaluated for TB according to the criteria of International Tumor Budding Consensus Conference (ITBCC) and PDC, and both parameters were scored on a three-grade scale as described for colorectal cancer previously (0: Grade0, 1–4: Grade1, 5–9: Grade2 and ≥10: Grade3) and classified as low (Grade0–2) and high (Grade3) TB/PDC. High TB/PDC was associated with diffuse-type morphology, higher pT status, incomplete surgical resection, poor tumor differentiation and perineural and lymphovascular invasion. Multivariable survival analyses have shown an independent prognostic role of high TB with poorer overall survival in the total cohort (p = 0.014) and in intestinal-type adenocarcinomas (p = 0.005). Multivariable model revealed high TB as an independent predictor for lymph node metastasis in both the total cohort (p = 0.019) and in the intestinal type adenocarcinomas (p = 0.038). In contrast to tumor budding, no significant association was found between PDC and the occurrence of lymph node metastasis and tumor stage and even survival. In conclusion, tumor budding is an independent prognostic factor of survival in gastric cancer, especially in intestinal-type adenocarcinomas.