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We compared the relative sensitivity of chicken embryos exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) injected either into the yolk or into the air cell. The TCDD was injected at the start of incubation (embryonic day 0) and the embryos were sacrificed at multiple times during embryonic development, A subset of embryos were allowed tohatch undisturbed. The chick embryo was significantly more sensitiveto TCDD when injected into the yolk than when injected into the air cell. The resultant median lethal dose (LD50) (122 pg/g egg, determined by probit analysis; 146 pg/g egg determined by interpolation) was 60% lower than the LD50 (297 pg/g egg by probit; 255 pg/g egg determined by interpolation) for air-cell-injected TCDD. A significant decrease in hatch weight of embryos exposed to high concentrations of TCDDcompared to controls occurred, and this decrease was even more pronounced at a lower concentration in the yolk-injected birds. Interestingly, during the period of embryonic days 11 through 15, the mean weight of the yolk-injected embryos was smaller than the mean weight of the air-cell-injected embryos. This difference was not noticeably evident just before or just after this developmental period. Embryos exposed to high concentrations of TCDD injected into either the yolk or the air cell tended to die within the first 2 weeks of incubation. A number of TCDD-exposed embryos survived the entire 21-d incubation period, but only air-cell-injected embryos were able to hatch successfully. Because the injection site varies in studies reported by different laboratories, the relative sensitivity must be considered when comparing results from different studies. [ABSTRACT FROM AUTHOR]

Bronchoscopic lung volume reduction is a procedure that involves placement of valves into the lung to intentionally cause atelectasis to help with perfusion-ventilation matching. There are strict exclusion criteria, such as hypercapnia, that prevent patients from qualifying for the procedure based on the early trials. We present a case of a patient that became a candidate for the procedure after utilizing AVAPS after BPAP failed to lower his PCO2 to qualify for the procedure. Additionally, newer studies show that patients who are hypercapnic might benefit from the procedure to improve hypercapnia., Competing Interests: No conflict., (© 2024 The Authors.)

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is a rare disease first reported in 2020, most commonly seen in men aged 56-75 years old. Common clinical features include skin lesions (83.5%), fever (63.6%), relapsing chondritis (36.4%), venous thrombosis (34.7%) and lymph node enlargement (33.9%). The patient is a man in his 40s who presented with testicular and lower extremity pain, followed by a rash and bicytopenia. He was initiated on corticosteroids and sulfasalazine. He was found to have mediastinal lymphadenopathy and underwent an endobronchial ultrasound and transbronchial needle aspiration followed by a video-assisted thoracic surgery biopsy which were unrevealing. Eventually, an ubiquitin-like modifier activating enzyme (UBA-1) gene analysis was performed that was consistent with VEXAS syndrome. Patients with VEXAS syndrome usually present with a red or violaceous rash and dyspnoea. Laboratory abnormalities include anaemia, elevated mean corpuscular volume, thrombocytopenia and elevated inflammatory markers. Diagnosis is based on the genetic mutation and associated symptoms. The treatment includes steroids and Janus kinase (JAK) inhibitors, specifically ruxolitinib., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

With the advent of bronchoscopic lung-volume reduction (BLVR), this minimally invasive technique represents a new and effective way of managing the debilitating symptoms associated with severe centrilobular emphysema. Despite its vast potential in the management of this disease, there are still several potential risk factors associated with the procedure that may predispose the patient to increased morbidity. Our patient received four endobronchial valves in the right-upper lobe (RUL) and right-middle lobe (RML). Although her immediate post-procedure course was uncomplicated, she returned shortly after discharge with a right-sided pneumothorax and right-lower lobar pneumonia with sputum culture growing methicillin-sensitive Staphylococcus aureus ( S. aureus ). She was managed with tube thoracostomy and two weeks of cefazolin with clinical improvement. Despite the abundance of literature detailing the risk of pneumonia following BLVR, very little data exists discussing common causative organisms, choice of treatment, duration of treatment, and potential risk factors that may predispose these patients to infection., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Assaad et al.)

The signal peptide region of preproinsulin (PPI) contains epitopes targeted by HLA-A-restricted (HLA-A0201, A2402) cytotoxic T cells as part of the pathogenesis of β-cell destruction in type 1 diabetes. We extended the discovery of the PPI epitope to disease-associated HLA-B*1801 and HLA-B*3906 (risk) and HLA-A*1101 and HLA-B*3801 (protective) alleles, revealing that four of six alleles present epitopes derived from the signal peptide region. During cotranslational translocation of PPI, its signal peptide is cleaved and retained within the endoplasmic reticulum (ER) membrane, implying it is processed for immune recognition outside of the canonical proteasome-directed pathway. Using in vitro translocation assays with specific inhibitors and gene knockout in PPI-expressing target cells, we show that PPI signal peptide antigen processing requires signal peptide peptidase (SPP). The intramembrane protease SPP generates cytoplasm-proximal epitopes, which are transporter associated with antigen processing (TAP), ER-luminal epitopes, which are TAP independent, each presented by different HLA class I molecules and N-terminal trimmed by ER aminopeptidase 1 for optimal presentation. In vivo, TAP expression is significantly upregulated and correlated with HLA class I hyperexpression in insulin-containing islets of patients with type 1 diabetes. Thus, PPI signal peptide epitopes are processed by SPP and loaded for HLA-guided immune recognition via pathways that are enhanced during disease pathogenesis., (© 2018 by the American Diabetes Association.)

Rhomboid intramembrane proteases are the enzymes that release active epidermal growth factor receptor (EGFR) ligands in Drosophila and C. elegans, but little is known about their functions in mammals. Here we show that the mammalian rhomboid protease RHBDL4 (also known as Rhbdd1) promotes trafficking of several membrane proteins, including the EGFR ligand TGFα, from the endoplasmic reticulum (ER) to the Golgi apparatus, thereby triggering their secretion by extracellular microvesicles. Our data also demonstrate that RHBDL4-dependent trafficking control is regulated by G-protein coupled receptors, suggesting a role for this rhomboid protease in pathological conditions, including EGFR signaling. We propose that RHBDL4 reorganizes trafficking events within the early secretory pathway in response to GPCR signaling. Our work identifies RHBDL4 as a rheostat that tunes secretion dynamics and abundance of specific membrane protein cargoes.

A 22-year-old Asian male presented with fever, non-productive cough, right-sided pleuritic chest pain and was found to have a large right hydropneumothorax. A chest tube was placed. Pleural fluid analysis revealed a lymphocytic predominant exudate and he was subsequently started on four-drug daily anti-tuberculosis therapy (isoniazid, ethambutol, rifampin, pyrazinamide). Pleural biopsy revealed acid-fast bacilli. Given his persistent pleural effusion, he was given four doses of intrapleural tissue plasminogen activator (tPA) and dornase alpha (DNase) via his chest tube over a period of 6 days resulting in clinical and radiologic improvement. Pleural biopsy and pleural fluid culture specimens later revealed Mycobacterium tuberculosis. Intrapleural tPA-DNase therapy has demonstrated improved resolution of infections and shortened hospitalizations for parapneumonic infectious effusions. However, there is little literature on the use of intrapleural fibrinolytics specifically for pleural tuberculosis associated effusions. Furthermore, the American Thoracic Society does not comment on therapeutic thoracentesis or intrapleural fibrinolytic therapy in their recommendations for treatment of pleural tuberculosis. In our case of pleural TB-associated hydropneumothorax, the use of intrapleural tPA-DNase therapy facilitated pleural fluid drainage and resulted in near-complete resolution of the effusion.

Mutations in PINK1 and PARK2/Parkin are a main risk factor for familial Parkinson disease. While the physiological mechanism of their activation is unclear, these proteins have been shown in tissue culture cells to serve as a key trigger for autophagy of depolarized mitochondria. Here we show that ablation of the mitochondrial rhomboid protease PARL leads to retrograde translocation of an intermembrane space-bridging PINK1 import intermediate. Subsequently, it is rerouted to the outer membrane in order to recruit PARK2, which phenocopies mitophagy induction by uncoupling agents. Consistent with a role of this retrograde translocation mechanism in neurodegenerative disease, we show that pathogenic PINK1 mutants which are not cleaved by PARL affect PINK1 kinase activity and the ability to induce PARK2-mediated mitophagy. Altogether we suggest that PARL is an important intrinsic player in mitochondrial quality control, a system substantially impaired in Parkinson disease as indicated by reduced removal of damaged mitochondria in affected patients.

Signal peptide peptidase (SPP) catalyzes intramembrane proteolysis of signal peptides at the endoplasmic reticulum (ER), but has also been suggested to play a role in ER-associated degradation (ERAD). Here, we show that SPP forms a complex with the ERAD factor Derlin1 and the E3 ubiquitin ligase TRC8 to cleave the unfolded protein response (UPR) regulator XBP1u. Cleavage occurs within a so far unrecognized type II transmembrane domain, which renders XBP1u as an SPP substrate through specific sequence features. Additionally, Derlin1 acts in the complex as a substrate receptor by recognizing the luminal tail of XBP1u. Remarkably, this interaction of Derlin1 with XBP1u obviates the need for ectodomain shedding prior to SPP cleavage, commonly required for intramembrane cuts. Furthermore, we show that XBP1u inhibits the UPR transcription factor XBP1s by targeting it toward proteasomal degradation. Thus, we identify an ERAD complex that controls the abundance of XBP1u and thereby tunes signaling through the UPR., (© 2014 The Authors.)

We present an interesting case of a young female smoker who was hospitalized for shortness of breath and acute renal insufficiency (serum creatinine = 2.8 mg/dL). Few weeks prior to admission, she was discovered to have a right lung mass, and a biopsy confirmed lung adenocarcinoma. Her work-up revealed an unremarkable urinalysis quantitatively and on microscopic analysis. Renal ultrasound demonstrated enlarged bilateral unobstructed kidneys, while a nuclear scan showed increased activity in both kidneys. Renal biopsy established the diagnosis of diffuse metastatic infiltration of both kidneys from primary lung adenocarcinoma. Her renal function worsened despite initiation of chemotherapy. Carcinomatous infiltration of the kidneys is an extremely rare and unusual cause of renal injury that must be suspected in a patient with cancer and large kidneys.

The established roles of flexible bronchoscopy in patients with diverse respiratory diseases, together with the demographic imperative posed by the aging of the population, make it important to understand factors relevant to this procedure in the elderly and to identify ways to optimize its performance. Relatively few investigations address specific influences of age on bronchoscopy but suggest that older patients age alone neither requires major modification of the approach nor introduces unacceptable hazards. The crucial relationships between bronchoscopy, the prevalence of specific respiratory diseases under consideration, and the impact of the procedure on patient management algorithms must be addressed in the future prospective investigations of the process of care in the elderly.

Although Jak kinases are essential for initiating cytokine signaling, the role of other nonreceptor tyrosine kinases in this process remains unclear. We have examined the role of Fes in IL-4 signaling. Examination of Jak1-deficient cell lines demonstrates that Jak1 is required for the activation of Fes by IL-4. Experiments studying signaling molecules activated by IL-4 receptor suggest that IL-4 signaling can be subdivided into Fes-dependent and Fes-independent pathways. Overexpression of kinase-inactive Fes blocks the IL-4 activation of insulin receptor substrate-2, but not STAT6. Fes appears to be a downstream kinase from Jak1/Jak3 in this process. Further examination of downstream signaling demonstrates that kinase-inactive Fes inhibits the recruitment of phosphoinositide 3-kinase to the activated IL-4 receptor complex and decreases the activation of p70(S6k) kinase in response to IL-4. This inhibition correlates with a decrease in IL-4-induced proliferation. In contrast, mutant Fes does not inhibit the activation of Akt by IL-4. These data demonstrate that signaling pathways activated by IL-4 require different tyrosine kinases. This differential requirement predicts that specific kinase inhibitors may permit the disruption of specific IL-4-induced functions.

Spatiotemporally regulated cell proliferation and differentiation are crucial for the successful completion of morphogenesis of the vertebrate secondary palate. An understanding of the mechanisms by which these cellular phenomena are regulated during palate development involves the identification of the various signal transduction pathways. In the present study, the presence and activation of mitogen-activated protein (MAP) kinases were investigated during the development of quail secondary palate. The palatal shelves were dissected on days 5-9 of incubation, homogenized, and centrifuged, after which the samples were separated by anion exchange fast protein liquid chromatography. The fractions were analyzed for myelin basic protein (MBP) phosphorylation. In addition, primary cultures of quail palate mesenchymal cells (QPMCs) were treated with epidermal growth factor (EGF) and prepared for MBP phosphorylation assays. A temporally regulated pattern of phosphotransferase activity, characterized by a three-fold increase in phosphotransferase activity toward MBP between days 5 and 8 of incubation, was observed during quail palate development. Western blotting, using MAP kinase antibodies, demonstrated the presence of a 42-kDa isoform between days 5 and 9 of incubation, during which the level of protein remained constant. Antityrosine immunoblotting with 4G10 also detected a 42-kDa protein. Phosphotransferase assays, using either a MAP kinase-specific substrate peptide (S5) or a protein kinase C inhibitor (R3), further confirmed the presence of a MAP kinase in the developing palate of quail. Because diverse biological processes occur concurrently during in vivo palate morphogenesis, the involvement of MAP kinase was explored further in primary cell culture. The data showed that EGF stimulated proliferation and activated 42-kDa MAP kinase in QPMCs. It is suggested that MAP kinase cascade may be involved in growth factor-regulated cell proliferation during morphogenesis of quail secondary palate.

Mitogen-activated protein (MAP) kinase has been implicated in signal transduction pathways that regulate cell cycle progression during the proliferation of eukaryotic cells. Previous studies have shown that a rapid burst of cell proliferation is a major event of the development of mammalian palatal shelves in a vertical direction. The present study analyzed the involvement of MAP kinase during the vertical development of the secondary palate in hamster. Palates were dissected at various times between days 10:00 and 12:00 of gestation, homogenized, centrifuged and fractionated on a Mono Q column by fast protein liquid chromatography. The fractions were assayed for phosphotransferase activity toward myelin basic protein, and also toward a synthetic peptide APRTPGGRR (S5), which was more specifically utilized by MAP kinase. The data showed that MAP kinase activity increased during the initial phase, i.e., between days 10:00 and 11:12, and then decreased during the latter half of vertical palate development, i.e., between days 11:12, and 12:00 of gestation. Western blotting studies, using antibodies raised against the subdomain I ATP binding sequence (GEGA), subdomain III (ERK1-III), and the C-terminus (ERK1-CT) of MAP kinases, demonstrated the presence of both the 42-kDa and 44-kDa MAP kinase isoforms between days 10:12 and 12:12 of gestation. A monoclonal antibody (4G10), which detects phosphotyrosine, demonstrated phosphorylation of both the 42-kDa and 44-kDa isoforms. The amount of protein remained constant during vertical palatal shelf development indicating that the differential activity of MAP kinase was most likely due to post-translational modification (i.e., phosphorylation). There was a good correlation between the temporal expression of MAP kinase activity and the rates of cell proliferation in the developing vertical palate suggesting a possible involvement of MAP kinase in regulation of cell proliferation during secondary palate development.

Background: During the progression of avian secondary palate morphogenesis, the rate of cell proliferation declines, whereas the production and accumulation of extracellular matrices increases. To investigate the regulation of these events, we examined the quail secondary palate for the activity of casein kinase 2 (CK 2), a pleiotropic serine/threonine second messenger independent enzyme implicated in cell growth and differentiation., Methods: Quail palatal shelves were dissected between days 5 and 9 of incubation, which is the period of palate morphogenesis in quail, and prepared either for light microscopic observations or homogenized, cleared by ultracentrifugation, and then subjected to fractionation on a MonoQ column by fast protein liquid chromatography and Western immunoblotting., Results: Histological examination showed that the palatal shelves appeared on day 5 of incubation and approximated by day 8 of incubation. Fractionation of palate extract using a Mono-Q column revealed the presence of a major peak of phosvitin phosphotransferase activity which eluted with 0.5 M NaCl. This activity peak coincided with the presence of a 42 kDa subunit of CK 2 as determined by Western blotting with a CK 2 specific antibody. The CK 2 activity towards phosvitin was elevated on days 5 and 6 and then rapidly declined by day 9. The decrease in CK 2 activity did not correlate with a decrease in CK 2 protein during palate development indicating that the differential activity of the CK 2 enzyme observed during quail palate development may be due to post-translational modifications of the enzyme. A high positive correlation was found between the CK 2 phosphotransferase activity and both the proliferation index and DNA synthesis during palate development., Conclusion: On the basis of literature analysis and the results of the present study, it was suggested that the activity of CK 2 may be regulated along with protein kinase A to coordinate cell proliferation and the synthesis of extracellular matrices during palate development in quail.

Background: Casein kinase 2 (CK 2) is a serine/threonine kinase that has been ubiquitously conserved in all eukaryotic cells. The exact functions of this enzyme have not yet been clarified; however, studies have repeatedly suggested that it may play crucial roles in the regulation of cell proliferation. During the formation of the secondary palate in the hamster, bursts of cell proliferation occur during the initial half of vertical shelf development, which decrease during the subsequent steps of palate morphogenesis, thus indicating that the cell cycle in the developing vertical palate may be tightly regulated., Methods: In the present study, palatal shelves were dissected at 12-hour intervals between days 10 and 12 of gestation, which is the period of vertical shelf development in the hamster. The palates were homogenized and cleared by ultracentrifugation and the resultant supernatants were fractionated on a Mono Q column by fast protein liquid chromatography., Results: Using phosvitin as a substrate, the phosphotransferase activity in the fractionated samples decreased steadily from days 10 to 11, increased to a fivefold peak on day 11:12, and then decreased on day 12 of gestation. Western blot analysis using two CK 2 specific antibodies demonstrated that both the 42-kDa (alpha) and the 38-kDa (alpha') subunits of the CK 2 holoenzyme were found throughout the formation of the vertical palatal shelves in the hamster. The amount of alpha and alpha' subunits appears to remain constant, which suggested that the differential activity of the CK 2 enzyme may be due to posttranslational modifications. CK 2 activity correlated well with DNA synthesis (i.e., cell proliferation) rates from days 10 to 11, but not from days 11 to 12 of gestation., Conclusions: It is proposed that the activity of CK 2 may regulate the rate of cell proliferation by stimulation of progression through G1 phase of the cell cycle and may also relate to the effects of various growth factors during the vertical development of mammalian palate.

With the aid of permanent cultured MDCK (Madin Darby Canine Kidney) epithelial cell a model for investigations dealing with phonophoresis effects was developed. The permeation of procaine hydrochloride through cell monolayers was examined while applying therapeutical ultrasound simultaneously. It could be shown that this permeation follows Higuchi kinetics. A comparison of the velocity factors, using a continuous irradiation of 1.0 W/cm2, shows about a 4.8 fold increase. Single Ultrasound pulses, however, result in a short-time enhancement of the permeation. The conclusion can be drawn that extent and velocity of the permeation of the permeation of procaine hydrochloride through MDCK monolayer can be controlled by phonophoresis.

A study was undertaken to analyze the spatio-temporal pattern of mesenchymal cell proliferation in the developing palate of quail. Quail embryos were grown in shell-less culture. The developing palates were labelled with 3H-thymidine between culture days 2-6 (which corresponded in vivo incubation days 5-9), and processed for light microscopic autoradiography. Percent labelled mesenchymal cells were determined. The data showed that, as in mammals, a high rate of random cell proliferation in mesenchyme was a major component of early palate development in quail. As the palate morphogenesis advanced, the rate of cell proliferation declined. Segmental analysis, however, indicated that, in contrast to mammals, the mesenchymal cell proliferation rates continually changed in various regions of quail palate during morphogenesis. It was suggested that the spatio-temporal changes in the distribution of dividing cells may reflect differences in the timings of cell cycles between various segments, thus resulting in a heterogeneous population of cells in the developing palate of quail. Further, the differences in the segmental pattern of cell proliferation between birds and mammals may form the basis for differences in the morphogenesis of their palates.

A comparative study was undertaken to investigate the effects of 5-fluorouracil (FU) on glycosaminoglycans (GAG) synthesis during morphogenesis of the secondary palate in birds (where, unlike mammals, palate morphogenesis begins in a horizontal direction ad initium and lacks mammalian-type shelf reorientation) and mammal. Previous studies have shown that FU induces cleft palate in both birds and mammals. Air sacs of quail eggs were injected with 100 micrograms FU in 0.1 ml saline or 0.1 ml saline only. Hamsters were given intramuscular injection of 81 mg/kg FU in 1 ml saline or 1 ml saline only. Total GAG synthesis was measured by incorporation of 3H-glucosamine. Sulfated and non-sulfated GAGs were identified by Alcian Blue histochemistry combined with the use of GAG-degrading enzymes. The results indicated that a continuous synthesis of GAG at a steady rate was associated with normal palate morphogenesis in both quail and hamster. The amount of GAG synthesized in hamster palate was four-fold higher than in quail palate. In contrast to the developing hamster palate where the predominant GAG was hyaluronate, the major GAGs present during quail palate development were sulfated and were concentrated on the nasal side. FU treatment did not affect the rate of GAG synthesis in the developing palate of quail. In contrast, FU administration altered the rates of GAG synthesis, and affected hyaluronate accumulation, during palate morphogenesis in hamster.(ABSTRACT TRUNCATED AT 250 WORDS)