[Application of cortical bone trajectory screw and sacral alar screw internal fixation for surgical treatment of lumbar adjacent segment degeneration].

Objective: To explore the application of cortical bone trajectory screw (CBTS) and sacral alar screw (SAS) internal fixation in the treatment of lumbar adjacent segment degeneration (ASD) and evaluate its clinical effect. Methods: Data of 24 patients who were diagnosed with ASD and treated by CBTS or SAS in Beijing Chaoyang Hospital were retrospectively reviewed. There were 14 males and 10 females with a mean age of (67.9±8.2) years. The patients were followed-up for (2.6±0.4) years. Perioperative parameters including operation time, intraoperative blood loss and postoperative time on the ground were counted. All patients were followed-up for at least 2 years. Visual analogue scale (VAS) and the Oswestry disability index (ODI) were compared between pre-operation and at the last follow-up. The internal fixation-related complications, pseudarthrosis and adjacent re-degeneration were evaluated in the follow-up. Results: There were 14 proximal ASD patients, 8 distal ASD patients, 1 both ends ASD patient and 1 ASD patient in between the fusion surgeries. Bone mineral density (BMD) T score of the adjacent vertebrae was -1.98±0.91 on average. The ASD patients were re-operated with CBTS and SAS internal fixation technique. A small incision was made in the revision surgery and the original fixation was not completely cut open and removed. The mean operation time was (125±36) min, mean blood loss was (85±33) ml. The postoperative ambulation time was (3.1±1.9) days, and the hospitalization time was (9.0±2.6) days. Before the operation, the average VAS (back pain) score was 5.2±1.0, the average of VAS (leg pain) score was 6.8±1.9 and ODI was 56.6%±12.8%. VAS score was reduced to 1.4±0.6 (waist pain) and 0.9±0.4 (leg pain). ODI was improved to 13.8%±6.3%. All the difference between preoperative and the last follow-up was statically significant (all P<0.01). No internal fixation failure, pseudarthrosis and adjacent re-degeneration were observed in the final follow-up. Conclusion: The application of CBTS and SAS internal fixation techniques in the surgical treatment of lumbar ASD has the advantages of less trauma, faster postoperative recovery, reliable internal fixation, and fewer complications, especially in patients with low bone mineral density.

[Analysis of the whole genome traceability and transmission path simulation experiment of the local cluster COVID-19 epidemic].

Objective: To trace and characterize the whole genome of SARS-CoV-2 of confirmed cases in the outbreak of COVID-19 on July 31, 2021 in Henan Province. Method: Genome-wide sequencing and comparative analysis were performed on positive nucleic acid samples of SARS-CoV-2 from 167 local cases related to the epidemic on July 31, 2021, to analyze the consistency and evolution of the whole genome sequence of virus. Results: Through high-throughput sequencing, a total of 106 cases of SARS-CoV-2 whole genome sequences were obtained. The results of genome analysis showed that the whole genome sequences of 106 cases belonged to the VOC/Delta variant strain (B.1.617.2 clade), and the whole genome sequences of 106 cases were shared with the genomes of 3 imported cases from Myanmar admitted to a hospital in Zhengzhou. On the basis of 45 nucleotide sites, 1-5 nucleotide variation sites were added, and the genome sequence was highly homologous. Conclusion: Combined with the comprehensive analysis of viral genomics, transmission path simulation experiments and epidemiology, it is determined that the local new epidemic in Henan Province is caused by imported cases in the nosocomial area, and the spillover has caused localized infection in the community. At the same time, it spills over to some provincial cities and results in localized clustered epidemics.

Drug-induced pyoderma gangrenosum: a model to understand the pathogenesis of pyoderma gangrenosum.

Pyoderma gangrenosum (PG) is a rare autoinflammatory condition in which the alteration of neutrophil function and the innate immune response play key roles in its pathogenesis. Cases of PG have been reported in patients being treated with certain medications, which may help us to understand some of the possible pathways involved in the aetiology of PG. The aim of this review is to review the cases of PG triggered by certain drugs and try to thoroughly understand the pathogenesis of the disease. To accomplish this, a PubMed search was completed using the following words: pyoderma gangrenosum, neutrophilic dermatosis, pathophysiology, drug-induced pyoderma gangrenosum. In total, we found 43 cases of drug-induced PG. Most of them were caused by colony-stimulating factors and small-molecule tyrosine kinase inhibitors. We propose that drugs induce PG through various mechanisms such as dysfunctional neutrophil migration and function, dysregulated inflammatory response, promotion of keratinocyte apoptosis and alteration of epigenetic mechanisms. PG is a rare condition with complex pathophysiology and drug-induced cases are even more scarce; this is the main limitation of this review. Understanding the possible mechanisms of drug-induced PG, via abnormal neutrophil migration and function, abnormal inflammation, keratinocyte apoptosis and alteration of epigenetic mechanisms would help to better understand the pathogenesis of PG and ultimately to optimize targeted therapy.

Comparative cell attachment, cytotoxicity and antibacterial activity of radiopaque dicalcium silicate cement and white-coloured mineral trioxide aggregate.

AIM: To comparatively examine the cell attachment, cytotoxicity, and antibacterial activity of radiopaque dicalcium silicate cement (RDSC) and ProRoot white-coloured mineral trioxide aggregate (WMTA). METHODOLOGY: AlamarBlue was used for real-time and repeated monitoring of MG63 cell attachment on freshly mixed and set cements. The pH changes in the growth medium at different time-points were also measured. Cytotoxicity evaluation was performed according to ISO 10993-5 specifications. The antibacterial activity of the cement specimens was evaluated using Enterococcus faecalis. RESULTS: There were no significant differences (P > 0.05) between the two cements for cell attachment either in the fresh groups or in the set groups at all culture times. Neither freshly mixed group nor set groups had significant pH differences. In the case of cytotoxicity, RDSC was significantly (P < 0.05) superior to WMTA at 12 and 24 h of incubation. RDSC and WMTA possessed similar antimicrobial activity, substantiated by the formation of growth inhibition zones and bacteriostasis ratio in E. faecalis strains. CONCLUSIONS: The cell attachment, cytotoxicity and antibacterial efficacy of RDSC were comparable to those reported for ProRoot WMTA. The results of the current study suggest that this RDSC could be used as a root-end filling material and root sealer.

Role of the p38 pathway in mineral trioxide aggregate-induced cell viability and angiogenesis-related proteins of dental pulp cell in vitro.

AIM: To investigate the influence of mineral trioxide aggregate (MTA) on angiogenesis of primary human dental pulp cells (hDPCs) via the MAPK pathway, in particular p38. METHODOLOGY: Human dental pulp cells were cultured with MTA to angiogenesis, after which cell viability, ion concentration, osmolality, NO secretion, the von Willebrand factor (vWF) and angiopoietin-1 (Ang-1) protein expression were examined. PrestoBlue(®) was used for evaluating the proliferation of hDPCs. An enzyme-linked immunosorbent assay was employed to determine vWF and Ang-1 protein secretion in hDPCs cultured on MTA and the control. Cells cultured on the tissue culture plate without the cement were used as the control. The t-test was used to evaluate the significance of the differences between the mean values. RESULTS: Mineral trioxide aggregate elicited a significant (P < 0.05) increased viability compared with the control (15%, 16% and 13% on days 1, 3 and 5 of cell seeding, respectively). MTA consumed calcium and phosphate ions, and released more Si ions in the medium. MTA significantly (P < 0.05) increased the osmolality of the medium to 313, 328 and 341 mOsm kg(-1) after 1, 3 and 5 days, respectively. P38 was activated through phosphorylation, and the phosphorylation kinase was investigated in the cell system after being cultured with MTA. Expression levels for Ang-1 and vWF in hDPCs on MTA were higher than those of the MTA + p38 inhibitor (SB203580) group (P < 0.05) at all of the time-points. CONCLUSIONS: Mineral trioxide aggregate was able to activate the p38 pathway in hDPCs cultured in vitro. Moreover, Si increased the osmolality required to facilitate the angiogenic differentiation of hDPCs via the p38 signalling pathway. When the p38 pathway was blocked by SB203580, the angiogenic-dependent protein secretion decreased. These findings verify that the p38 pathway plays a key role in regulating the angiogenic behaviour of hDPCs cultured on MTA.

Enhancement of mouse cytomegalovirus infection during host-versus-graft reaction.

C3H/He mice chronically infected with murine cytomegalovirus were given skin allografts from histoincompatible BALB/c donors. A significant increase in cytomegalovirus titers occurred within 3 days after placement of the graft in the spleens and kidneys of the allograft recipients as compared with control animals. No significant changes in virus titers were detected in the salivary gland, lung, liver, or blood of allograft recipients. These results indicate that the host-versus-graft reaction alone can enhance murine cytomegalovirus in a chronically infected host and may help explain the high incidence of cytomegalovirus infection seen after renal and other allograft transplantation in man.

Comparison of nuclear proteins of several human tumors and normal cells by two-dimensional gel electrophoresis.

Using isoelectric focusing and sodium dodecyl sulfate two-dimensional gel electrophoresis, 9 M urea-extractable nuclear proteins from four human tumor cells (HeLa, Namalwa, acute myelogenous leukemia, and lymphoma) and four normal human cells (IMR-90, WI-38, liver, and lymphocytes) were compared. Two protein spots, 140/7.7 and 54/6.6, were found in all four tumor cells but not in the four normal cells studied. Two protein spots, 56/6.7 and 56/6.9, were found in all four normal cells but not in any of the tumors studied. None of these proteins was common to those found in the earlier studies on rat tumors (H. Takami et al., Cancer Res., 39: 2096-2105, 1979).

Isolation and characterization of a cytosol protein (64/7.2) present in large amounts in rapidly growing hepatomas.

Protein 64/7.2 (molecular weight/isoelectric point) is present in the cytosol of several hepatomas including the Novikoff hepatoma and Morris hepatomas 9618A, 7794A, and 3924A, but it is not present in liver or 18-hr regenerating liver. Quantitatively, its concentration was highest in Novikoff hepatoma (150 microgram/g tissue) and Morris hepatoma 3924A (550 microgram/g tissue), which are rapid-growing tumors, less in Morris hepatoma 7794A (72 microgram/g tissue), which is of intermediate growth rate, and least in the slow-growing Morris hepatoma 9618A (25 microgram/g tissue). Protein 64/7.2 was isolated from Novikoff hepatoma ascites cells in high purity as shown by its migration as a single band on one-dimensional acid-urea-polyacrylamide gels and a single spot on two-dimensional isoelectric focusing sodium dodecyl sulfate-polyacrylamide gels. Its amino acid composition has an acidic to basic amino acid ratio of 1.6. Its amino-terminal amino acid is lysine, and its carboxyl-terminal amino acid is glycine. Interestingly, the amino acid composition is strikingly similar to that of the phosphorylated Novikoff hepatoma chromatin Protein Cg', partially characterized in our laboratory.

Antigenically active nonhistone chromatin proteins in cancer cells.

Two-dimensional polyacrylamide gel electrophoresis shows that in nuclei of Novikoff hepatoma ascites cells there are approximately 75 proteins in the chromatin fraction soluble in 3 M NaCl:7 M urea. Dialysis of this fraction to an ionic strength of 0.15 produces a soluble fraction and a precipitate. The proteins in the soluble fraction have been reported to be active in gene control. Antibodies to the soluble fraction distribute diffusely throughout the nucleus, and antibodies to the precipitate localized primarily in the nucleolus and the nuclear ribonucleoprotein network. The nucleolar proteins differ from the extranucleolar proteins in antigenicity and labeling patterns. The development of methods for isolation, purification, and identification of nuclear proteins provided the opportunity for analysis of chromatin antigens in tumor cells. Utilizing two-dimensional preparative polyacrylamide gel techniques as well as conventional procedures, several nuclear proteins have been isolated in electrophoretically homogeneous states including protein A-24, a histone-like nonhistone protein; C-14, a protein that stimulates nucleolar RNA polymerase; and a chromatin antigen soluble in 3 M NaCl:7 M urea that remains soluble after dialysis to 0.15 M NaCl to precipitate the histones and the DNA. This antigen has been found in the chromatin of both the Novikoff hepatoma and the Walker 256 carcinosarcoma but not in the chromatin of either normal or regenerating liver. It is a nonhistone nuclear protein as indicated by its amino acid analysis in which the ratio of the number of acidic to basic amino acids is approximately 1.4. Further studies are in progress on the function and structure of this chromatin protein. As an approach to analysis of relative rates of synthesis of this antigen and otherproteins, the products of translation of messenger RNA of Novikoff hepatoma and normal liver are being analyzed by autoradiography of two-dimensional electrophoretic gels.

Chronic herpes simplex infection in cutaneous T-cell lymphomas.

Therapeutically unresponsive erosive or ulcerative lesions caused by the herpes simplex virus developed in five patients with advanced cutaneous T-cell lymphoma. The chronic progressive character of the herpetic infection probably was the consequence of immunosuppression resulting from advanced lymphoma or its treatment. Herpes simplex infection should be considered in the differential diagnosis of cutaneous ulcerations in patients with cutaneous T-cell lymphomas.

Dimethylnitrosamine-demethylase: absence of increased enzyme catabolism and multiplicity of effector sites in repression. Hemoprotein involvement.

Evidence is presented that the previously observed decrease of the Vmax of hepatic microsomal demethylation of dimethylnitrosamine (DMN), following pretreatment of rats with 3-methylcholanthrene (MC), is not due to increase in the rate of breakdown but to decrease of de novo synthesis. Determinations of Vmax at time intervals in the transition from the high steady-state level induced by a carbohydrate-devoid casein diet, down to the low steady-state level of carbohydrate-containing basal diet, yielded two consecutive slopes; descent from the basal diet level to the lower steady-state level following pretreatment with MC yielded one slope. Plotting these slopes against the initial Vmax values gave a typical exponential curve (or straight line if the logs of slopes are used) indicating that the rate of enzyme decay in the MC-treated animals is not greater than that expected from normal enzyme catabolism. A multiplicity of effector sites appears to be involved in the repressor action of different structural types; for example, repression by MC (46.6%) and by phenobarbital (23.9%) in combination are approximately additive (62.0%), rather than competitive, indicating that the two agents act at different sites. A P-450 type cytochrome is involved in the demethylation of DMN. DMN-demethylase is inhibited by carbon monoxide, but the susceptibility to CO is far greater than that observed previously with 3,4-benzopyrene hydroxylation; inhibition of DMN-demethylase as a function of CO concentration follows typical enzyme kinetics. However, while both phenobarbital and MC powerfully repress the DMN-demethylase, we have confirmed that they are strong inducers of the synthesis of P-450 and P-448, respectively, as estimated from the difference spectra.

Computed tomography analysis of knee pose and geometry before and after total knee arthroplasty.

Using a three-dimensional (3D) modality to image patients' knees before and after total knee arthroplasty (TKA) allows researchers and clinicians to evaluate causes of pain after TKA, differences in implant design, and changes in the articular geometry as a result of surgery. Computed tomography (CT) has not been fully utilized to date for evaluating the knee after TKA due to metal artifacts obscuring part of the image. We describe an accurate, validated protocol, which has been implemented in vivo, that improves visibility of the patellofemoral joint, matches implant models automatically in 3D, segments preoperative bone semi-automatically, detects and sets coordinate systems automatically, determines the six degrees of freedom of knee pose and geometry, and allows for multiple other measurements that are clinically relevant. Subjects are imaged at 0° and 30° knee flexion, while pushing on a custom-made knee rig to provide partial loadbearing. With some modifications, the protocol can be adopted by any group with access to a CT scanner and image analysis software, allowing for the investigation of numerous clinical and biomechanical questions.

Suspended aggregates as an immobilization mode for high-density perfusion culture of HEK 293 cells in a stirred tank bioreactor.

Cells of the human embryonic kidney cell line (HEK 293) grown in repeated suspension and perfusion systems were characterized and described. Cell aggregates that formed immediately after the HEK 293 cells were inoculated in stirred vessels in serum-containing Dulbecco's modified Eagle's medium (D-MEM)/F-12 medium. The mean diameter of the cell aggregates reflecting the aggregate size increased with culture time, shifting from 63 to 239 mum after 1 and 8 days of culture in spinner flasks, respectively. No significant differences in cell performance were observed between HEK 293 cell populations grown as suspended aggregates and those grown as anchored monolayers. Replacing the D-MEM/F-12 with CD 293 medium caused the compact spherical cell aggregates to dissociate into single cells and small irregular aggregates without any apparent effect on cell performance. Moreover, the spherical cell aggregates could reform from individual cells and small aggregates when exposed to the serum-containing D-MEM/F-12 dominant medium. Perfusion culture of HEK 293 cells grown as suspended aggregates in a 7.5-l stirred tank bioreactor for 17 days resulted in a maximum viable cell density of 1.2 x 10(7) cells ml(-1). These results demonstrate the feasibility and proof-of-concept for using aggregates as an immobilization system in large-scale stirred bioreactors because a small-scale culture can be used as easily as the inoculum for larger bioreactors.

Characteristics of infection of B and T lymphocytes from mice after inoculation with cytomegalovirus.

Viremia was produced by inoculating intravenously BALB/c mice with murine cytomegalovirus. Virus was detected in plasma and granulocytes only during the first 8 days after infection. Lymphocyte-associated viremia, detectable by cocultivation on syngeneic or allogeneic fibroblasts, persisted for at least 4 weeks. Eight to 10 days after infection, sonicated lymphocytes had no demonstrable free virus. When whole lymphocytes with no demonstrable free virus were enclosed in a Millipore chamber and placed on a fibroblastic feeder layer, T cells produced free virus but B cells did not. Compared to normal calf serum, specific hyperimmune serum reduced B cell-associated infectious centers by 74% and T cell-associated infectious centers by only 38%. Normal mouse sera reduced by 36% and 30% infectious center production by B cells and T cells, respectively. Lymphocytes enriched with Fc receptor-positive cells produced significantly more infectious centers than receptor-negative cells.

Two-dimensional gel electrophoresis of nuclear phosphoproteins of Novikoff hepatoma and regenerating liver.

Two-dimensional polyacrylamide gel electrophoresis patterns of 32P-labeled nuclear proteins in Novikoff hepatoma and regenerating liver relatively small number of the many nuclear protein spots were phosphorylated. The major phosphoprotein spots differed in size and shape from the stained protein spots. Seven phosphoproteins, 125/5.8, 125/7.2, 100/5.9, 85/5.9, 56/5.1, and 50/5.1 (mol. wt. x 10-(3)/pI in the Novikoff hepatoma nuclei were not found in the 18-h regenerating liver nuclei. One nuclear phosphoprotein, 54/6.5, was found in the liver but not in the hepatoma. The four major phosphoproteins, 45/5.3-6.0, 40/5.3-6.0, 35/5.3-6.0, and 25/5.8-6.8 containing about 60% of the total 32Pi of the nuclear proteins, were found in both types of cells. These proteins were of unusual density and shape. Some proteins, such as 125/5.8 and 85/5.9, were enriched in 0.01 M tris extract of the tumor, and proteins 125/7.2 and 56/6.1 were enriched in 0.35 M NaCl extract of the tumor.