Update from the 5th Edition of the WHO Classification of Nasal, Paranasal, and Skull Base Tumors: Imaging Overview with Histopathologic and Genetic Correlation

Sinonasal and skull base tumors are a heterogeneous group of neoplasms with considerable histologic variation and overlapping imaging features. In 2022, the World Health Organization updated the head and neck tumor classification, further emphasizing the importance of molecular data and genetic alterations in sinonasal neoplasms. The changes include the addition of new entities and discussion of emerging entities, as well as changes to the taxonomy and characterization of tumors. The new classification focuses on entities that develop in these sites either exclusively (eg, olfactory neuroblastoma) or most frequently. Another change includes reduction in the number of categories by creating separate category-specific chapters for soft-tissue, hematolymphoid, and neuroectodermal lesions. In this review, we briefly discuss the various categories in the new classification with a more detailed description of the 2 new entities (SWItch/Sucrose Non-Fermentable complex-deficient sinonasal carcinomas and human papillomavirus-related multiphenotypic sinonasal carcinoma). We also highlight the emerging entities including IDH-mutant sinonasal malignancies and DEK-AFF2 carcinoma, presently classified as sinonasal undifferentiated carcinoma and nonkeratinizing squamous cell carcinoma, respectively.

Synthesis of a dihydroquinoline based fluorescent cyanine for selective, naked eye, and turn off detection of Fe3+ions

A cyanine dye was synthesized by condensing 6-formylated 1,2,2,4-tetramethyl-1,2-dihydroquinoline (TMDQ) and 1,7-dimethyl-2-phenylimidazo[1,2-a]pyridin-1-ium iodide.

Synthesis of a dihydroquinoline based merocyanine as a ‘naked eye’ and ‘fluorogenic’ sensor for hydrazine hydrate in aqueous medium and hydrazine gas

1,2,2,4-Tetramethyldihydroquinoline (TMDQ) is formylated at the 6-position and the resulting quinoline aldehyde is condensed with 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one to obtain a merocyanine 6-pyrazolinyl TMDQ.

Phenotypic detection of Extended Spectrum Beta-Lactamases and Amp C Beta- Lactamases among nosocomial isolates in a tertiary care hospital

Background & objectives: Extended-Spectrum Beta-Lactamases (ESBLs) is an important resistance mechanism in Enterobacteriaceae infections. Lack of standard guidelines from Clinical Laboratory Standards Institute (CLSI) for Amp C beta-lactamase detection poses a problem. This study was undertaken to detect ESBLs by phenotypic tests and Amp C beta-lactamase by inhibitor based method. Material and Methods: 200 consecutive non-repetitive isolates of E.coli, Klebsiella and Proteus from clinical samples were screened for ESBLs as per CLSI guidelines and confirmed by PCDT, DDST and E-tests (AB Biodisk, Biomerieux). Amp C beta lactamases were screened by cefoxitin resistance and confirmed by inhibitor (Cloxacillin) based method. Simultaneous occurrence of Amp C and ESBLs was detected by combined disk test (Neo-Sensitabs and Diatabs). Descriptive and Kappa statistics were used. Results: Out of 200 isolates studied, 131 were initially screened as ESBL producers and later 114 (57%) were confirmed by phenotypic methods. E-Test was found most sensitive phenotypic test as compared to PCDT and DDST. 13 strains resistant to cefoxitin (30?g) were found to be pure Amp C producers. Combined disk test detected 36 to be ESBL and Amp C co-producers. Surprisingly, six isolates found sensitive to cefoxitin disk were confirmed as Amp C producers by cloxacillin disk inhibition test. Conclusion: 57% ESBLs and 27.5% Amp C producers were isolated from nosocomial pathogens showing significant resistance to 3rd generation cephalosporins. Phenotypic confirmation by E-test, PCDT & DDST were useful for ESBL identification and for detection of Amp C, cloxacillin was found to be an effective inhibitor. DOI: http://dx.doi.org/10.3329/bjms.v12i4.13309 Bangladesh Journal of Medical Science Vol. 12 No. 04 October ’13 Page 378-384

Adhesive small bowel obstruction (ASBO) in children--role of conservative management

Adhesive small bowel obstruction (ASBO) is an annoying postoperative complication. Though the diagnosis can be made easily, the role of conservative management in children is controversial. Hence a study was conducted to determine the role of conservative management, and to identify the factors that can predict / influence the outcome of conservative treatment in children with ASBO. Children admitted with ASBO from 1980 to 2002 (22 year period) formed the material for this study. The data was analyzed with respect to the influence of age at the time of presentation, primary disease for which original laparotomy was done, time interval between the primary surgery and the development of ASBO and the number of laparotomies prior to the development of ASBO on the outcome of conservative management. There were 74 episodes of ASBO in 69 children (Five children had two episodes). Out of 74 episodes, 5 episodes (6.75%) needed immediate laparotomy for suspected gangrene. All others were managed conservatively. Of the 69 episodes managed conservatively, 36 responded to conservative treatment (2-5 days) while 33 required subsequent surgical intervention, with 11 of them requiring bowel resection (two for gangrene and 9 for bowel damage during adhesiolysis) and in the rest 22 cases adhesiolysis. A substantial number of children with ASBO respond well to conservative treatment. Majority of the children developed ASBO within three months after the primary laparotomy. Children below the age of one year (at the time of presentation with ASBO) responded poorly to the conservative management. Children who had primary surgery for Hirschsprung's disease and intussusception also appeared to have responded poorly to conservative management, but statistically not significant. Time interval between the primary surgery and the number of laparotomies before the child developed ASBO did not influence the outcome of conservative management.

Catalytic function of an alpha/beta hydrolase is required for energy stress activation of the sigma(B) transcription factor in Bacillus subtilis

The general stress response of Bacillus subtilis is controlled by the sigma(B) transcription factor, which is activated in response to diverse energy and environmental stresses. These two classes of stress are transmitted by separate signaling pathways which converge on the direct regulators of sigma(B), the RsbV anti-anti-sigma factor and the RsbW anti-sigma factor. The energy signaling branch involves the RsbP phosphatase, which dephosphorylates RsbV in order to trigger the general stress response. The rsbP structural gene lies downstream from rsbQ in a two-gene operon. Here we identify the RsbQ protein as a required positive regulator inferred to act in concert with the RsbP phosphatase. RsbQ bound RsbP in the yeast two-hybrid system, and a large in-frame deletion in rsbQ had the same phenotype as a null allele of rsbP-an inability to activate sigma(B) in response to energy stress. Genetic complementation studies indicated that this phenotype was not due to a polar effect of the rsbQ alteration on rsbP. The predicted rsbQ product is a hydrolase or acyltransferase of the alpha/beta fold superfamily, members of which catalyze a wide variety of reactions. Notably, substitutions in the presumed catalytic triad of RsbQ also abolished the energy stress response but had no detectable effect on RsbQ structure, synthesis, or stability. We conclude that the catalytic activity of RsbQ is an essential constituent of the energy stress signaling pathway.

A PP2C phosphatase containing a PAS domain is required to convey signals of energy stress to the sigmaB transcription factor of Bacillus subtilis

The sigmaB transcription factor of the bacterium Bacillus subtilis is activated by growth-limiting energy or environmental challenge to direct the synthesis of more than 100 general stress proteins. Although the signal transduction pathway that conveys these stress signals to sigmaB is becoming increasingly well understood, how environmental or energy stress signals enter this pathway remains unknown. We show here that two PP2C serine phosphatases - RsbP, which is required for response to energy stress, and RsbU, which is required for response to environmental stress - each converge on the RsbV regulator of sigmaB. According to the current understanding of sigmaB regulation, in unstressed cells the phosphorylated RsbV anti-anti-sigma is unable to complex the RsbW anti-sigma, which is then free to bind and inactivate sigmaB. We can now advance the model that either PP2C phosphatase, when triggered by its particular class of stress, can remove the phosphate from RsbV and thereby activate sigmaB. The action of the previously described RsbU is known to be controlled by dedicated upstream signalling components that are activated by environmental stress. The action of the RsbP phosphatase described here requires an energy stress, which we suggest is sensed, at least in part, by the PAS domain in the amino-terminal region of the RsbP phosphatase. In other bacterial signalling proteins, similar PAS domains and their associated chromophores directly sense changes in intracellular redox potential to control the activity of a linked output domain.

Serine kinase activity of a Bacillus subtilis switch protein is required to transduce environmental stress signals but not to activate its target PP2C phosphatase

The RsbT serine kinase has two known functions in the signal transduction pathway that activates the general stress factor sigmaB of Bacillus subtilis. First, RsbT can phosphorylate and inactivate its specific antagonist protein, RsbS. Second, upon phosphorylation of RsbS, RsbT is released to stimulate RsbU, a PP2C phosphatase, thereby initiating a signalling cascade that ultimately activates sigmaB. Here we describe a mutation that separates these two functions of RsbT. Although the mutant RsbT protein had essentially no kinase activity, it still retained the capacity to stimulate the RsbU phosphatase in vitro and to activate sigmaB when overexpressed in vivo. These results support the hypothesis that phosphatase activation is accomplished via a long-lived interaction between RsbT and RsbU. In contrast, RsbT kinase activity was found to be integral for the transmission of external stimuli to sigmaB. Thus, one route by which environmental stress signals could enter the sigmaB network is by modulation of the RsbT kinase activity, thereby controlling the magnitude of the partner switch between the RsbS-RsbT complex and the RsbT-RsbU complex.

Prostacyclin is a potent anti-mutagen

Prostacyclin (PGI2) prevented genetic damage to the bone marrow cells of mice induced by gamma-radiation, benzo(a)pyrene(BP) and cis-platinum(cis-DDP). Carba-PGI2, an analogue of PGI2, was also effective against cis-DDP-induced mutagenicity. In a time-course study it was observed that the geno-protective action of PGI2, can last as long as 24 hr. 6-keto-PGF1 alpha, a major metabolite of PGI2 and c-AMP, a second messenger, were ineffective in bringing about this beneficial action. PGI2 did not influence free radical generation induced by phorbol myristate acetate in human peripheral leukocytes. This suggests that the genoprotective action of PGI2 is not mediated by its metabolite 6-keto-PGF1 alpha and the second messenger cyclic-AMP and is not due to any action on free radical generation. This geno-protective action of PGI2 would be futile if it interfered with the tumoricidal action of cis-DDP. It was observed that the cytotoxic action of cis-DDP against Meth-A tumor cells was not interfered with by PGI2 and carba-PGI2 both in vitro and in vivo. This description of the geno-protective action of PGI2 is important in the development of new strategies in cancer chemotherapy since, it is likely that anticancer drugs, at least cis-DDP can be given along with PGI2 to prevent genetic damage to normal cells without interfering with their tumoricidal action.