[Analysis of the efficacy of fiber laser stapes fenestration in the treatment of 58 cases of otosclerosis and ossicular malformation].

Objective: To explore the surgical efficacy of conductive deafness caused by otosclerosis and ossicular malformation with 980 nm fiber laser stapedial floor fenestration. Methods: Data of 58 patients (ears) who were diagnosed with conductive deafness caused by otosclerosis (49 ears) and ossicular malformation (9 ears) treated by 980 nm Diode laser small-fenestra stapedotomy were retrospectively analyzed. Air conduction (AC) thresholds, bone conduction (BC) thresholds, and air-bone gap (ABG) at 0.5, 1, 2, 4 kHz pure tone frequencies were compared before and 3 months after surgery, and the advantages and precautions of 980 nm fiber laser were summarized. Paired t-test (SPSS 26.0 software) was use to analyze the listening data. Results: Fiber optic laser stapes fenestration and artificial stapes implantation were successfully completed in all 57 cases (ears), the hearing of another one patient (ear) with floating malformation of detachment of stapedial floor was lower than that before surgery. Preoperative at 0.5, 1, 2, 4 kHz frequencies of AC thresholds, BC thresholds, and ABG were (65.4±9.7) dB, (27.2±8.9) dB, and (38.2±9.8) dB respectively. Postoperative 3 months at the same frequency of AC thresholds, BC thresholds, and ABG were (42.1±11.3) dB, (26.9±6.6) dB, and (15.2±9.1) dB. Preoperative and postoperative of AC threshold and ABG were statistically significant at 0.5, 1, 2, 4 kHz (t value was 13.270 and13.948, both P<0.01), and yet the BC threshold was not statistically significant before and after surgery at the same frequency (t=0.418, P>0.05). Conclusions: 980 nm fiber laser stapes floor fenestration is an effective treatment for conductive deafness caused by otosclerosis and ossicular malformation.

[Cell heterogeneity of laryngeal carcinoma and evolution trajectory of epithelial cells].

Objective: To analyze the classification and functions of cell subsets in laryngeal carcinoma and metastatic lymph nodes, and to explore the evolution trajectory of epithelial cells to tumor cells. Methods: Single-cell RNA sequencing was performed on 5 cases of laryngeal cancer, matched metastatic lymph nodes and 3 normal tissues. Patients were admitted to Ningbo Medical Center Lihuili Hospital from October 22, 2019 to December 16, all patients were male, aged 53-70 years old. Cell subsets of the above-mentioned tissues were analyzed by the Seurat, and the biological functions of cell subpopulation were investigated by functional enrichment analysis. Malignant epithelial cells were identified using copy number variation (CNV). The evolutionary trajectory of epithelial cells to cancer cells was analyzed by cell trajectory analysis, and cancerous transitional cells were identified. The highly expressed genes in transitional cells were analyzed by the FindAllMarker of the Seurat and verified by immunohistochemistry. Results: A total of 66 969 high-quality cells were obtained in 9 major clusters: epithelial cells, T cells, B cells, fibroblasts, endothelial cells, myeloid cells, mast cells, plasmacytoid dendritic cells and nerve cells. The first 5 cell clusters were divided into 8, 6, 4, 3 and 2 subgroups, respectively. Four epithelial cell subsets (C0, C1, C2 and C5) were derived from tumor tissues and metastatic lymph nodes, and had high levels of CNV and tumor cell content. Cell trajectory analysis showed that the evolution trajectory of epithelial cells was from normal epithelial subpopulation C4 to early cancerous cell population C0, which differentiated into three major malignant cell subsets C1, C3, and C5. Epithelial cell C0 may represent the transitional cell population of carcinogenesis, and were enriched in biological processes such as epithelial-mesenchymal transformation and angiogenesis. C0 highly expressed sulforaphane (SFN) which may be related to the occurrence and development of cancer. Immunohistochemistry confirmed that SFN was highly expressed in tumor tissues and metastatic lymph nodes compared with paracancerous tissues. Conclusion: Single-cell sequencing may be used to elucidate the diversity of cells and functions in laryngeal carcinoma tissues and metastatic lymph nodes, and cell population C0 plays a key role in the evolution of cells.

The appropriate hybrid surgical strategy in three-level cervical degenerative disc disease: a finite element analysis.

OBJECTIVE: The purpose of this FE study was to analyze the biomechanical characteristics of different HS strategies used in the treatment of three-level CDDD (one-level CDA and two-level ACDF). METHODS: We validated the FE model of an intact cervical spine established by transferring the data, collected by 3D CT scan, to the FE software ABAQUS and comparing these data with the data from published studies. Then, the FE model of hybrid surgery was reconstructed to analyze the range of motion (ROM), facet joint force, and stress distribution on an ultrahigh molecular weight polyethylene (UHMWPE) core. RESULTS: The current cervical FE model was able to measure the biomechanical changes in a follow-up hybrid surgery simulation. The total ROM of the cervical HS models was substantially decreased compared with the total ROM of the intact group, and the M2 (C3/4 ACDF, C4/5 CDA, and C5/6 ACDF) model had the closest total ROM to the intact group, but the facet joint force adjacent to the treatment levels showed very little difference among them. The stress distribution showed noticeable similarity: two flanks were observed in the center core, but the inlay of M2 was more vulnerable. CONCLUSIONS: Through the comparison of ROM, the facet joint force after CDA, and the stress distribution of the prosthesis, we find that M2 model has a better theoretical outcome, especially in preserving the maximum total ROM.

Overexpression of miR-215-3p sensitizes colorectal cancer to 5-fluorouracil induced apoptosis through regulating CXCR1.

OBJECTIVE: Chemo-resistance of colon cancer remains a major problem in therapy. The role of miR-215-3p in the chemo-sensitivity of colon cancer remains unidentified. PATIENTS AND METHODS: Here, we constructed a 5-Fluoracil (5-Fu) resistant HCT116 cell line (HCT116/5-Fu) and miR-215-3p expression levels were measured in 56 cases of colon cancer tissues and 23 cases of normal tissues by quantitative real-time polymerase chain reaction (qRT-PCR). The effects of miR-215-3p on colon cancer cell growth and apoptosis were investigated using cell counting kit-8 (CCK-8) and apoptosis assay, respectively. In addition, CXC-chemokine receptor type1 (CXCR1) was identified as a target of miR-215-3p by using luciferase reporter assay. RESULTS: miR-215-3p was down-expressed in the 5-FU resistant cell compared to the parent cell. The level of miR-215-3p was correlated with the 5-Fu sensibility of colorectal cancer cell and the alteration of miR-215-3p affected the sensibility of colorectal cancer cells toward 5-Fu. Furthermore, miR-215-3p accelerated the apoptosis of colorectal cancer cell which was treated with 5-Fu. Mechanically, miR-215-3p regulated the level of endogenous CXCR1 in HCT116 cell and alternation of CXCR1 affected the 5-Fu sensibility mediated by miR-215-3p. Finally, overexpression of miR-215-3p restrained the growth of HCT116/5-Fu cells in the xenograft model. CONCLUSIONS: MiR-215-3p improved the 5-Fu sensibility via regulating the expression of CXCR1 in the colorectal cancer cell.

Finite element analysis of posterior cervical fixation.

BACKGROUND CONTEXT: Despite largely, used in the past, biomechanical test, to investigate the fixation techniques of subaxial cervical spine, information is lacking about the internal structural response to external loading. It is not yet clear which technique represents the best choice and whether stabilization devices can be efficient and beneficial for three-column injuries (TCI). HYPOTHESIS: The different posterior cervical fixation techniques (pedicle screw PS, lateral mass screw LS, and transarticular screw TS) have respective indications. MATERIALS AND METHODS: A detailed, geometrically accurate, nonlinear C3-C7 finite element model (FEM) had been successfully developed and validated. Then three FEMs were reconstructed from different fixation techniques after C4-C6 TCI. A compressive preload of 74N combined with a pure moment of 1.8 Nm in flexion, extension, left-right lateral bending, and left-right axial rotation was applied to the FEMs. RESULTS: The ROM results showed that there were obvious significant differences when comparing the different fixation techniques. PS and TS techniques can provide better immediate stabilization, compared to LS technique. The stress results showed that the variability of von Mises stress in the TS fixation device was minimum and LS fixation device was maximum. Furthermore, the screws inserted by TS technique had high stress concentration at the middle part of the screws. Screw inserted by PS and LS techniques had higher stress concentration at the actual cap-rod-screw interface. CONCLUSIONS: The research considers that spinal surgeon should first consider using the TS technique to treat cervical TCI. If PS technique is used, we should eventually prolong the need for external bracing in order to reduce the higher risk of fracture on fixation devices. If LS technique is used, we should add anterior cervical operation for acquire a better immediate stabilization.

Clinical analysis of gastroenteropancreatic neuroendocrine tumor with liver metastasis, compared with primary hepatic neuroendocrine tumor.

OBJECTIVE: The objective was to study the clinicopathologic features, grading, treatment protocols, and prognostic of gastroenteropancreatic neuroendocrine tumor (NET) with liver metastasis and primary hepatic NET. MATERIALS AND METHODS: The clinical data of 34 patients with hepatic NET were retrospectively reviewed. According to the primary tumor location and 2010 World Health Organization classification, the cases were categorized to analyze the clinicopathologic features, treatment condition, and prognostic factors. RESULTS: There was a marked male predominance either in gastroenteropancreatic NET liver metastasis group or primary group. Primary hepatic NET is mostly single nodule located in the right lobe of liver, and the metastatic hepatic NET is mostly from pancreas with multiple nodules and metastasizes to both lobes of the liver, with a high degree of malignancy and poor prognosis. There are 17 cases (50%) of NET and 17 cases (50%) of neuroendocrine carcinoma (NEC) in all the 34 patients of this study. The mitotic figure and Ki-67 proliferation index are both higher in NEC group than in NET group, which indicated highly malignancy of the NEC. The 5-year disease-free survival (DFS) rates for primary group and metastatic group were 30% and 40%, respectively (P > 0.05), while the 5-year survival rates were 35% and 66%, respectively (P > 0.05). Different tumor grade was found closely associated with 5-year DFS (P < 0.05) and overall survival (OS) (P < 0.05) in both groups. Furthermore, we found 5-year DFS of patients with primary site of the tumor located in the gastrointestinal tract was much lower than that located in pancreas (P < 0.05), while the 5-year OS showed no significant differences between two groups (P > 0.05). CONCLUSIONS: Surgery is an effective method for the treatment of hepatic NET; tumor grading is an important determinant factor of prognosis.

Diffusion tensor imaging and 1H-MRS study on radiation-induced brain injury after nasopharyngeal carcinoma radiotherapy.

AIM: To investigate the metabolic characteristics of the temporal lobes following radiation therapy for nasopharyngeal carcinoma using diffusion tensor imaging (DTI) and proton magnetic resonance spectroscopy ((1)H-MRS). MATERIALS AND METHODS: DTI and (1)H-MRS were performed in 48 patients after radiotherapy for nasopharyngeal carcinoma and in 24 healthy, age-matched controls. All patients and controls had normal findings on conventional MRI. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), three eigenvalues λ1, λ2, λ3, N-acetylaspartic acid (NAA)/choline (Cho), NAA/creatinine (Cr), and Cho/Cr were measured in both temporal lobes. Patients were divided into three groups according to time after completion of radiotherapy: group 1, less than 6 months; group 2, 6-12 months; group 3, more than 12 months. Mean values for each parameter were compared using one-way analysis of variance (ANOVA). RESULTS: Mean FA in group 1 was significantly lower compared to group 3 and the control group (p < 0.05). Group-wise comparisons of apparent diffusion coefficient (ADC) values among all the groups were not significantly different. Eigenvalue λ1 was significantly lower in groups 1 and 3 compared to the control group (p < 0.05). NAA/Cho and NAA/Cr were significantly lower in each group compared to the control group (p < 0.01 for both). The decrease in NAA/Cho was greatest in group 1. There were no significant between-group differences regarding Cho/Cr. CONCLUSION: A combination of DTI and (1)H-MRS can be used to detect radiation-induced brain injury, in patients treated for nasopharyngeal carcinoma.

Radiation enhances long-term metastasis potential of residual hepatocellular carcinoma in nude mice through TMPRSS4-induced epithelial-mesenchymal transition.

Recurrence and metastasis are frequently observed after radiotherapy for hepatocellular carcinoma (HCC), although upregulation of matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) induced by radiation has been claimed to be involved, the mechanism is not clarified yet. In the present study, by using MHCC97L, a human HCC cell line with metastatic potential, and its xenograft in nude mice, we found that radiation induced a 48- to 72-h temporary increase in the expression of MMP-2 and VEGF both in vitro and in vivo, but only the in vitro invasiveness of MHCC97L cells was enhanced, while the in vivo metastatic potential of tumors was suppressed. Whereas, 30 days after radiation, when the expression of MMP-2 and VEGF decreased to unirradiated control levels, the in vivo dissemination and metastatic potential of residual tumors have just begun to increase with overexpression of TMPRSS4, which induced loss of E-cadherin through induction of Smad-Interacting Protein 1 (SIP1), an E-cadherin transcriptional repressor, and led to epithelial-mesenchymal transition (EMT). This process was blocked by treatment of siRNA-TMPRSS4. In conclusion, our study revealed novel findings regarding the biphasic effect of radiation on the metastatic potential of residual HCC. Overexpression of TMPRSS4 has a critical role in radiation-induced long-term dissemination and metastasis of residual HCC by facilitating EMT. These findings may provide new clues to suppress the radiation-induced dissemination and metastasis, thereby improve the prognosis of HCC patients.

Primary intracranial choriocarcinoma: MR imaging findings.

PICCC is the rarest, most malignant primary intracranial GCT. The purpose of this study was to describe and characterize the MR imaging findings in a series of 7 patients (6 males and 1 female; mean age, 11.9 years) with pathologically proved PICCC in our institution from 2004 to 2009. All tumors were located within the pineal (n = 6) or suprasellar (n = 1) regions. On T2-weighted MR imaging, the lesions appeared markedly heterogeneous with areas of both hypointensity and hyperintensity reflecting the histologic heterogeneity, including hemorrhage, fibrosis, cysts, or necrosis. Heterogeneous (n = 7), ringlike (n = 4), and/or intratumoral nodular (n = 3) enhancement was noted on T1-weighted images with gadolinium. These MR imaging findings, combined with patient age and serum ß-HCG levels, may prove helpful in distinguishing PICCC from the more common primary brain tumors, thereby avoiding biopsy of this highly vascular tumor.

Sirolimus-based immunosuppression therapy in liver transplantation for patients with hepatocellular carcinoma exceeding the Milan criteria.

AIM: Sirolimus (SRL) acts as a primary immunosuppressant or antitumor agent. The aim of the present study was to evaluate the influence of SRL on the recurrence rate and survival of patients after orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC) exceeding the Milan criteria. MATERIALS AND METHODS: We retrospectively examined 73 consecutive patients who underwent OLT for HCC exceeding the Milan criteria from March 2004 through December 2005. Among them, 27 patients were treated with SRL-based immunosuppressive protocols after OLT, and 46 patients by an FK506-based protocol. Statistical analysis was based on the intent-to-treat method. RESULTS: The 2 groups were comparable in all clinicopathologic parameters. The mean overall survival was 594 +/- 35 days in the SRL group and 480 +/- 42 days in the FK506 group (P = .011); the mean disease-free survival period was 519 +/- 43 days in the SRL group and 477 +/- 48 days in the FK506 group (P = .234). Multivariate analysis revealed Child's status (P = .004) and immunosuppressive protocol (P = .015) were the significant factors affecting overall survival. Only microvascular invasion (P = .004) was significantly associated with disease-free survival. Among 24 surviving patient in the SRL group, 2 patients had SRL discontinued for toxicity; 10 had SRL monotherapy immunosuppression. CONCLUSION: The SRL-based immunosuppressive protocol improved the overall survival of patients after OLT for HCC exceeding the Milan criteria, probably by postponing recurrence and with better tolerability.

Combined IL-12 and GM-CSF gene therapy for murine hepatocellular carcinoma.

Among various immunotherapeutic approaches, interleukin-12 (IL-12) is particularly appealing because of its superior antitumor effects, which have been demonstrated in preclinical as well as clinical studies. However, IL-12 therapy was often accompanied by severe side effects due mainly to the supranormal induction of interferon-gamma. To optimize the therapeutic efficacy and lower the side effects of IL-12, we have investigated the antitumor activity of combined IL-12 and granulocyte-macrophage colony-stimulating factor (GM-CSF) gene therapy in a highly malignant and poorly immunogenic murine hepatocellular carcinoma model. Using a versatile hydrodynamics-based DNA delivery method, we showed that the combined gene delivery of IL-12 and GM-CSF induced very strong antitumor cellular immunity and achieved significant therapeutic efficacy, whereas each cytokine gene alone yielded appreciable but less effects. We also observed that the combined therapy induced lower levels of interferon-gamma than did IL-12 alone. These results suggest that combined IL-12 and GM-CSF therapy can render a stronger antitumor effect as well as lowering potential side effects.

Complete resection of the caudate lobe of the liver with tumor: technique and experience.

BACKGROUND/AIMS: To study the technique and curative effects of complete resection of the caudate lobe of the liver with tumors. METHODOLOGY: There were 18 patients with tumors in the caudate lobe of the liver in this study. Among them, hepatocellular carcinoma was found in 12 patients, metastasis to the caudate lobe two years after resection of rectal carcinoma in one, cholangiocarcinoma in one, and huge benign tumor in four. Complete caudate lobectomy and combined with left lateral lobectomy or left hemihepatectomy or left trilobectomy were performed in this series. RESULTS: The median operating time was 227 min and median blood loss was 1590 mL, and the median blood transfusion was 1520 mL. No operative or postoperative mortality, or any postoperative complications were found in any of the patients. The 1-, 3- and 5-year survival rates of the 12 patients with hepatocellular carcinoma were 58.3%, 55.5% and 37.8%, respectively. One patient with cholangiocarcinoma died in postoperative 4 months. One patient with metastatic rectal cancer has been alive for more than 5 years after the operation, and 4 patients with benign tumors are still alive and well. CONCLUSIONS: Complete resection of the caudate lobe of the liver should be the first choice for removal of huge tumors originating from the caudate lobe, although this procedure is quite difficult and has a high risk factor.

Multimodality treatment in hepatocellular carcinoma patients with tumor thrombi in portal vein.

AIM: To compare the therapeutic effect and significances of multimodality treatment for hepatocellular carcinoma (HCC) with tumor thrombi in portal vein (PVTT). METHODS: HCC patients (n=147) with tumor thrombi in the main portal vein or the first branch of portal vein were divided into four groups by the several therapeutic methods. There were conservative treatment group in 18 out of patients (group A); and hepatic artery ligation(HAL) and/or hepatic artery infusion (HAI) group in 18 patients (group B), in whom postoperative chemoembolization was done periodically; group of removal of HCC with PVTT in 79 (group C) and group of transcatheter hepatic arterial chemoembolization (TACE) or HAI and/or portal vein infusion (PVI) after operation in 32 (group D). RESULTS: The median survival period was 12 months in our series and the 1-,3-, and 5-year survival rates were 44.3%, 24.5% and 15.2%, respectively. The median survival times were 2, 5, 12 and 16 months in group A, B, C and D, respectively. The 1-, 3- and 5-year survival rates were 5.6%, 0% and 0% in group A; 22.2%, 5.6% and 0% in group B; 53.9%, 26.9% and 16.6% in group C; 79.3%, 38.9% and 26.8% in group D, respectively. Significant difference appeared in the survival rates among the groups (P < 0.05). CONCLUSION: Hepatic resection with removal of tumor thrombi and HCC should increase the curative effects and be encouraged for the prolongation of life span and quality of life for HCC patients with PVTT, whereas the best therapeutic method for HCC with PVTT is with regional hepatic chemotherapy or chemoembolization after hepatic resection with removal of tumor thrombi.

An approach for difficult hepatectomy--retrograde hepatectomy in 29 patients with liver malignant tumor.

BACKGROUND/AIMS: Resection remained the best treatment for malignant liver tumor. However, it is difficult to resect a tumor which is huge and tightly invaded or adhered to the surrounding organs by classical procedures because of poor exposure. The purpose of the present study was to verify that retrograde hepatectomy was an acceptable approach. METHODOLOGY: Retrograde hepatectomy means that the operative procedure is reversed as compared with classical methods. Transection of the liver parenchymal was performed first, isolating adhesions between the resected liver and diaphragm or partial phrenectomy followed, and then after cutting corresponding ligaments, the liver tumor was removed. If the adjacent organs were invaded or adhered too tightly to be separated, they were removed with the resected liver. This approach was adopted in 29 patients with liver malignancy (group A) for difficult hepatectomy from June 1994 to June 1997. In the same period, classical hepatectomy was performed in 13 patients used as a control group (group B). The differences between these two groups were analyzed. RESULTS: When group A was compared with group B, the operative mortality was 0% versus 7.7% (p > 0.05), the operative time was shorter, being 175.9 +/- 49.7 min (range: 150-250 min) versus 251.9 +/- 66.9 min (range: 180-360 min) (p < 0.05), the estimated intra-operative blood loss being 1430.0 +/- 807.6 ml (600-4200 ml) versus 2907.7 +/- 1497.9 ml (800-7000 ml) (p < 0.05), and the incidence of post-operative complications was lower (p < 0.05). CONCLUSIONS: Retrograde hepatectomy is an alternative method to classical hepatectomy and suitable for resection of localized huge liver tumor when the exposure is inadequate by classical approach, particularly when the tumor adheres or invades closely to the diaphragm and/or the surrounding structures.

Improved survival with resection after transcatheter arterial chemoembolization (TACE) for unresectable hepatocellular carcinoma.

AIM: This retrospective study was undertaken to analyze the outcome of hepatic resection in hepatocellular carcinomas (HCCs) that shrunk after transcatheter hepatic arterial chemoembolization (TACE) in 65 patients with unresectable HCCs between June 1987 and September 1996. MATERIALS AND METHODS: Among these 65 patients, the median diameter of the tumor was 9.9 cm (5.6-20.0) prior to the first TACE, after 1-6 times of TACE (median 3) the median tumor diameter reduced to 3.7 cm (1.9-12.5) prior to resection. The duration between the last TACE treatment and sequential resection varied from 1 to 9 months (median 2.5). Serum alpha-fetoprotein (AFP) levels were abnormal in 39 out of the 65 patients. In AFP producing HCCs, the AFP level returned to normal (

The expression of the mdm2 gene may be related to the aberration of the p53 gene in human hepatocellular carcinoma.

The relationship between mdm2 gene expression and p53 gene mutation in hepatocellular carcinoma (HCC) and their correlation with the invasiveness of the disease were investigated in this study. Either the expression level of the mdm2 gene or the mutation rate of the p53 gene was higher in HCC than in paratumor liver tissues. Studies on the relationship between mdm2 and p53 revealed that mdm2 gene expression in HCC without p53 mutation was higher than when there was p53 mutation, while the p53 mutation rate in HCC with mdm2 overexpression was significantly lower than in HCC without mdm2 overexpression. Among 23 HCC with invasion, mdm2 gene overexpression was found in 6 patients while p53 mutation was found in the other 11 patients, and only 1 patient was found to have both mdm2 overexpression and p53 mutation. These results indicated that either mdm2 overexpression or p53 mutation may be related to the invasiveness of HCC. Considering that an autoregulatory feedback loop between the mdm2 and p53 genes may exist, wild-type P53 can induce the expression of mdm2 via a p53-binding site in the mdm2 gene, while MDM2 protein functions as a negative regulator of P53 protein. These results also suggest that mdm2 may be related to the high invasiveness of HCC through inactivating the tumor-suppressor function of the p53 gene.

[The arch structure of trabeculae in normal femoral head and its biomechanical significance].

The microstructure of normal femoral head of human was observed under light and electron microscope. Most of the trabeculae were seen in the form of arch structure, and the collagen fibers and the mineral columns of trabeculae were arranged in different directions. This finding provides a new explanation of mechanism that femoral head can bear high stress without collapse.

[Ultrastructural investigation of experimental fracture healing: effect of fixation with plates of various materials].

The right tibiae of 45 new zealand rabbits were osteotomized and internally fixed with plate of methylmethacrylate (MMA) or stainless steel (SS) with or without compression. The animals were divided into 3 groups, 15 in each. The ultrastructure of the specimens are as follows. Repair of the fractures immobilized with MMA plate went through a typical course of secondary healing, showing obvious periosteal, contact and medullary callus. The fibroblasts, chondroblasts and osteoblasts were numerous and very active throughout the healing period, demons treating an extremely active synthesis and secretion function. Findings in fractures fixed with SS plate without compression manifested atypical secondary healing. The early callus was mainly of contact and medullary one, the periosteal callus set in rather late. The fibroblasts were active, but not the osteoblasts, and even less in some chondroblasts. Fractures fixed with SS plate with compression healed primarily on the plate side, while the opposite side showed fissure healing, like that without compression. Intramedulla repair looked similar to that of fissure healing. Although the fibroblasts and osteoblasts were much like that in the group without compression, no chondroblasts came into action. All these biological differences are supposed to be response to the magnitude of stress at the fracture site.