Alterations in hepatic kinase activity following whole body gamma-irradiation of mice

The chronological activation of the signaling molecules following whole body gamma-irradiation was investigated in mouse liver. The activity of two kinases, tyrosine kinase and protein kinase C (PKC), was found to respond differently to gamma-irradiation. Tyrosine kinase was found to respond to much lower doses of irradiation (10 cGy), whereas PKC was found to be activated at comparatively higher doses (3 Gy). Tyrosine kinase showed a sharp activation at 30 min and then a decline to normal values at 1 h. Activation of PKC was apparent at as early as 15 min of irradiation and showed a maximal increase at 30 min. This was followed by a decline to normal values at 1 h. The response of the whole organ was found to be different from that of reported effects on a single cell. These results suggest that the data obtained from the single-cell studies would have limited application in the experiments involving the whole animal. Interruption of these signals at various steps is currently being used to manipulate tumor response to radiotherapy. In such cases, the difference in response of a single cell and a whole animal must be considered.     

Genomic DNA insertions and deletions occur frequently between humans and nonhuman primates

Comparative DNA sequence studies between humans and nonhuman primates will be important for understanding the genetic basis of the phenotypic differences between these species. Here we compare approximately 27 Mb of human chromosome 21 with chimpanzee DNA sequences identifying 57 genomic rearrangements (deletions and insertions ranging in size from 0.2 to 8.0 kb) between the two species. These rearrangements are distributed along the entire length of chromosome 21, with approximately 35% found in genomic intervals encoding genes (genic intervals), and have occurred in the genomes of both humans and chimpanzees. Comparison of approximately 9 Mb of human chromosome 21 with orangutan, rhesus macaque, and woolly monkey DNA sequences identified a combined total of 114 genomic rearrangements between humans and nonhuman primates. Analysis of these rearrangements revealed that they are randomly distributed with respect to genic and nongenic intervals and identified one deletion that has likely resulted in the inactivation of a gene (beta1,3-galactosyltransferase) in the woolly monkey. Our data show that genomic rearrangements have occurred frequently during primate genome evolution and significantly contribute to the DNA differences between these species. These DNA rearrangements are commonly found in genic intervals, and thus provide natural starting points for focused investigations of qualitative and quantitative gene expression differences between humans and other primates.     

Histological detection of minimal metastatic involvement in axillary sentinel nodes: a rational basis for a sensitive methodology usable in daily practice.

There is no consensus method for the histological analysis of axillary sentinel nodes (SN). This study aimed to (1) assess the rate of occult metastases in SN using large serial sectioning and immunohistochemistry (IHC), (2) evaluate whether occult metastases were predictive of metastases in the downstream axillary nodes, and (3) specify a methodology of analysis of SN that could be both sensitive and applicable in daily practice. One hundred three patients with breast carcinoma underwent SN biopsy and then axillary dissection. SN free of tumor at standard examination of one section were sectioned at six levels (150-microm intervals) and immunostained for cytokeratin. The number and localization of labeled metastatic cells (occult metastases) were recorded. In 29 of the 103 patients (28%), SN were found to be metastatic after standard examination. The SN of the remaining 74 patients were further analyzed using IHC. Occult metastases were detected in 35 of these patients (47.3%), leading to an overall SN involvement rate of 62% (29+35/103). In 33 of these 35 cases, the plurality and the dispersion of the immunostained cells implied that the screening of only 3 of the 6 levels would have led to the detection of diagnostic positive events. Only one of the 35 patients (2.8%) with occult metastases showed metastatic lymph node in the downstream axilla. In our series of axillary SN, the analysis of one standard histologic section and, when negative, of only three additional sections after IHC revealed >60% of metastasis or occult metastasis. Metastasis detected by standard analysis had a high predictive value of downstream node metastasis, whereas the predictive value of occult metastasis revealed by IHC was poor. The clinical significance of occult metastases in SN needs to be specified by long-term follow-up analysis.     

Cell membrane-associated MT1-MMP-dependent activation of pro-MMP-2 in A375 melanoma cells.

Matrix metalloproteinases (MMPs), a family of zinc-dependent endopeptidases, can degrade extracellular matrix components under physiological conditions and during cancer invasion and metastasis. Among the MMPs, the 72 kDa type IV collagenase MMP-2 (gelatinase A) is activated in a membrane-associated manner by an activation complex composed of membrane type 1 matrix metalloproteinase (MT1-MMP), tissue inhibitor of matrixmetalloproteinase-2 (TIMP-2), and pro-MMP-2 in the presence of alphavbeta3 integrin receptor. The activation of pro-MMP-2 correlates with increased occurrence of metastases. Increased MMP-2 activity has been demonstrated in many human tumors. In the present communication, we studied cell surface-associated activation of MMP-2 (72 kDa collagenase type IV) in the moderately metastatic human melanoma cell line A375. RESULTS: Activation of purified 72 kDa collagenase type IV, pro-MMP-2 from cervical cancer tissue homogenate and from serum-free culture medium of HT1080 cells grown in presence of concanavalin A, by A375 cells, was shown by gelatin zymography. A375 cells activated only pro-MMP-2 from purified MMP-9/MMP-2 mixture indicating that the activation is specific for MMP-2. Activation of MMP-2 and purified collagenase type IV by A375 membrane fraction and membrane extract was also demonstrated by gelatin zymography. When A375 cells were first incubated with anti-MT1-MMP polyclonal antibody, activation of collagenase type IV was significantly decreased, indicating that membrane-associated MMP-2 activation is MT1-MMP-mediated. Immunocytochemistry showed MT1-MMP localization at focal adhesion sites. The presence of the components of activation complex-MT1-MMP and integrin alphavbeta3-were confirmed by Western blot, cell adhesion assay, and integrin subunit assay. CONCLUSION: Our experimental findings furnish another example of the unique membrane-associated MMP-2 activation mechanism in A375 melanoma cells and clearly indicate the role of MT1-MMP in MMP-2 activation. The information could help in developing new therapies designed to interfere with MMP activation and management of cancer and metastases.     

Extracorporeal membrane oxygenation with lepirudin anticoagulation for Wegener's granulomatosis with heparin-induced thrombocytopenia

Venovenous extracorporeal membrane oxygenation with lepirudin anticoagulation was successfully used for a complicated case of Wegener's granulomatosis and heparin-induced thrombocytopenia. Interestingly, a linear correlation was found between activated partial thromboplastin time and activated clotting time during lepirudin anticoagulation.     

Comparison of capsid polypeptides of group B coxsackieviruses and polypeptide synthesis in infected cells

Summary Capsid polypeptides of all six types (B1–6) of group B coxsackieviruses were compared by high-resolution gel electrophoresis, and synthesis of protein and RNA in B4- or B5-infected HeLa cells was analyzed. Four polypeptides, VP1–4, were detected in each type. Another polypeptide, VP0, slightly larger than VP1, was also detected in trace amounts in some types. VP1–3 showed different but characteristic molecular weights (VP1, 34,500 to 37,000; VP2, 31,000 to 36,000; VP3, 26,000 to 32,500), and presented well-defined and reproducible differences in electrophoretic mobility. The molecular weight of VP4 ranged from 5,000 to 5,500. VP1 was largest in B2 and B4, smallest in B1, and of intermediate size in the other types. VP2 was largest in B4 and smallest in B2; VP3 was largest in B5 and B6 and smallest in B4. In B4- or B5-infected HeLa cells, host protein synthesis began to decline after 2 hours postinfection and was less than 20 percent of the control by 6 hours postinfection. Actinomycin D-resistant viral RNA synthesis started at about 2 hours postinfection, peaked by 5 hours, and then declined rapidly. Virus-specific protein synthesis began while host protein synthesis was declining, increased during the ensuing period, and declined in late infection. A number of virus-specific proteins with molecular weights from 23,500 to >92,500 were detected in the host cytoplasm. At least three of these proteins were also present in the nucleus. The kinetics of processing of virus-specific proteins were examined by pulse-chase experiments in B5-infected cells. The relative intensities of [³⁵S]-methionine-labeled polypeptides suggest that a number of smaller, stable chains (MW 23,500 to 38,000) are generated by cleavage of a precursor polypeptide (MW 92,500 to 100,000).With 7 Figures     

Intraductal papillary mucinous neoplasm of the pancreas presenting as acute pancreatitis

Intraductal papillary mucinous neoplasms are rare pancreatic exocrine tumors with distinct clinicopathologic features. They usually present with a long history of chronic pancreatitis-like symptoms, which are often associated with weight loss, diarrhea, and malabsorption. We report a case of benign intraductal papillary mucinous neoplasm with focal squamous metaplasia presenting as acute necrotizing pancreatitis. The clinicopathologic features are discussed in a brief review of the literature.     

Needle necropsy in AIDS

The value of autopsy in understanding the natural course of any disease is beyond any argument. The reluctance of pathologists to perform autopsy in HIV infected cadavers is justified due to the risks involved to the prosector and the morgue attendants. A relative low risk needle necropsy protocol is proposed using fine needle aspiration cytology, tru-cut biopsies and microbiological examination. Diagnosis could be offered in all the forty-four needle necropsies performed. Disseminated tuberculosis in 18/44 (40.9%) cases, disseminated cryptococcosis in 12/44 (27.2%) cases, poly-microbial infections in 27.2% cases and non-Hodgkin's lymphoma in 9% cases were detected in the study. Infectious agents like Histoplasma capsulatum, Isospora belli, tachyzoites of Toxoplasma gondii, Candida sp and Cryptococcus sp could be demonstrated in the samples obtained in the study. Lack of material for study of gross pathology, inaccessibility of deep-seated lesions and risk of needle stick injury to the prosector though low are the limitations of this procedure.     

Surgery for infective endocarditis—analysis of factors affecting outcome

PurposeDespite advances in medical care, infective endocarditis (IE) has high mortality. Surgery for IE though recommended for complications of the disease is still not commonly offered due to conflicting reports in the literature. We reviewed our results of surgery for IE from the last 5 years to assess their outcome.MethodsA retrospective review from a single center of consecutive patients who underwent surgery for infective endocarditis from September 2014 to December 2019 was done. Data was collected from hospital records and follow-up done up to May 2020. Outcomes evaluated were mortality, follow-up survival, and postoperative complications. Factors affecting mortality and survival were analyzed.ResultsNinety-seven patients underwent surgery for IE during this period. Seventy-nine had native valve endocarditis (NVE) and 18 had prosthetic valve endocarditis (PVE). The overall postoperative mortality was 13%, with mortality for native valve endocarditis being 11% and that for prosthetic valve endocarditis being 22%, which was not statistically significant. Three-year survival for the overall group was 88.7% with 88.1% for NVE and 91.7% for PVE. Multivariate predictors of operative mortality were a high EuroSCORE II, diabetes mellitus, and the presence of Staphylococcus organism.ConclusionSurgery for infective endocarditis has a very acceptable early outcome and intermediate-term survival.