Designing an anatomical contour titanium 3D-printed oblique lumbar interbody fusion cage with porous structure and embedded fixation screws for patients with osteoporosis

This study aimed to design an anatomical contour metal three-dimensional (3D)-printed oblique lateral lumbar interbody fusion (OLIF) cage with porous (lattices) structure and embedded screw fixation to enhance bone ingrowth to reduce the risk of cage subsidence and avoid the stress-shielding effect. Finite element (FE) analysis and weight topology optimization (WTO) were used to optimize the structural design of the OLIF cage based on the anatomical contour morphology of patients with osteoporosis. Two oblique embedded fixation screws and lattice design with 65% porosity and average pore size of 750 μm were equipped with the cage structure. The cage was fabricated via metal 3D printing, and static/dynamic compression and compressive-shear tests were performed in accordance with the ASTM F2077-14 standard to evaluate its mechanical resistance. On FE analysis, the OLIF cage with embedded screw model had the most stability, lowest stress values on the endplate, and uniform stress distribution versus standalone cage and fixed with lateral plate under extension, lateral flexion, and rotation. The fatigue test showed that the stiffnesses/endurance limits (pass 5 million dynamic test) were 16,658 N/mm/6000 N for axial load and 19,643 N/mm/2700 N for compression shear. In conclusion, an OLIF cage with embedded fixation screws can be designed by integrating FE and WTO analysis based on the statistical results of endplate morphology. This improves the stability of the OLIF cage to decrease endplate destruction. The complex contour and lattice design of the OLIF cage need to be manufactured via metal 3D printing; the dynamic axial compression and compressive-shear strengths are greater than that of the U.S. Food and Drug Administration (FDA) standard.

Biomechanical evaluation of an osteoporotic anatomical 3D printed posterior lumbar interbody fusion cage with internal lattice design based on weighted topology optimization

In this study, we designed and manufactured a posterior lumbar interbody fusion cage for osteoporosis patients using 3D-printing. The cage structure conforms to the anatomical endplate’s curved surface for stress transmission and internal lattice design for bone growth. Finite element (FE) analysis and weight topology optimization under different lumbar spine activity ratios were integrated to design the curved surface (CS-type) cage using the endplate surface morphology statistical results from the osteoporosis patients. The CS-type and plate (P-type) cage biomechanical behaviors under different daily activities were compared by performing non-linear FE analysis. A gyroid lattice with 0.25 spiral wall thickness was then designed in the internal cavity of the CS-type cage. The CS-cage was manufactured using metal 3D printing to conduct in vitro biomechanical tests. The FE analysis result showed that the maximum stress values at the inferior L3 and superior L4 endplates under all daily activities for the P-type cage implantation model were all higher than those for the CS-type cage. Fracture might occur in the P-type cage because the maximum stresses found in the endplates exceeded its ultimate strength (about 10 MPa) under flexion, torsion and bending loads. The yield load and stiffness of our designed CS-type cage fall into the optional acceptance criteria for the ISO 23089 standard under all load conditions. This study approved a posterior lumbar interbody fusion cage designed to have osteoporosis anatomical curved surface with internal lattice that can achieve appropriate structural strength, better stress transmission between the endplate and cage, and biomechanically tested strength that meets the standard requirements for marketed cages.

Development of a Novel Hybrid Suture Anchor for Osteoporosis by Integrating Titanium 3D Printing and Traditional Machining

The aim of this study is to develop a titanium three-dimensional (3D) printing novel hybrid suture anchor (HSA) with wing structure mechanism which can be opened to provide better holding power for surrounding osteoporotic bone. A screw-type anchor (5.5-mm diameter and 16-mm length) was designed with wing mechanism as well as micro dual-thread in the outer cortex bone contact area and macro single-thread in the anchor body. Both side wings can be opened by an internal screw to provide better bone holding power. The suture anchor and internal screw were manufactured using Ti6Al4V 3D printing and traditional machining, respectively. Static pullout and after dynamic 300-cyclic load (150 N) pullout tests for HSA with or without the wing open and commercial solid anchor (CSA) were performed (n = 5) in severely osteoporotic bone and osteoporotic bone to evaluate failure strengths. Comparison of histomorphometrical evaluation was performed through in vivo pig implantation of HSAs with the wing open and CSAs. The failure strengths of HSA with or without the wing open were 2.50/1.95- and 2.46/2.17-fold higher than those of CSA for static and after dynamic load pullout tests in severely osteoporotic bone, respectively. Corresponding values for static and after dynamic load pullout tests were 1.81/1.54- and 1.77/1.62-fold in osteoporotic bone, respectively. Histomorphometrical evaluation revealed that the effects of new bone ingrowth along the anchor contour for CSA and HSA were both approximately 20% with no significant difference. A novel HSA with wing mechanism was developed using 3D printing and the opened wing mechanism can be used to increase bone holding power for osteoporosis when necessary. Better failure strength of HSA than CSA under static and after dynamic load pullout tests and equivalence of bone ingrowth along the anchor contours confirmed the feasibility of the novel HSA.

Development and Biomechanical Evaluation of an Anatomical 3D Printing Modularized Proximal Inter-Phalangeal Joint Implant Based on the Computed Tomography Image Reconstructions

In this study, we developed a modularized proximal interphalangeal (PIP) joint implant that closely resembles the anatomical bone articular surface and cavity contour based on computed tomography (CT) image reconstruction. Clouds of points of 48 groups reconstructed phalanx articular surfaces of CT images, including the index, middle, ring, and little fingers, were obtained and fitted to obtain the articular surface using iterative closest points algorithm. Elliptical-cone stems, including the length, the major and minor axis at the stem metaphyseal/diaphyseal side for the proximal and middle phalanxes, were designed. The resurfacing PIP joint implant components included the bi-condylar surface for the proximal phalanx with elliptical-cone stem, ultra-high molecular weight polyethylene bi-concave articular surface for middle phalanx with hook mechanism, and the middle phalanx with elliptical-cone stem. Nine sets of modularized designs were made to meet the needs of clinical requirements and the weakness structure from the nine sets, that is, the worst structure case combination was defined and manufactured using titanium alloy three-dimensional (3D) printing. Biomechanical tests including anti-loosening pull-out strength for the proximal phalanx, elliptical-cone stem, and articular surface connection strength for the middle phalanx, and static/dynamic (25000 cycles) dislocation tests under three daily activity loads for the PIP joint implant were performed to evaluate the stability and anti-dislocation capability. Our experimental results showed that the pull-out force for the proximal phalanx implant was 727.8N. The connection force for the hook mechanism to cone stem of the middle phalanx was 49.9N and the hook mechanism was broken instead of stem pull out from the middle phalanx. The static dislocation forces/dynamic fatigue limits (pass 25000 cyclic load) of daily activities for piano-playing, pen-writing, and can-opening were 525.3N/262.5N, 316.0N/158N, and 115.0N/92N, respectively, and were higher than general corresponding acceptable forces of 19N, 17N, and 45N from the literatures. In conclusion, our developed modularized PIP joint implant with anatomical articular surface and elliptical-cone stem manufactured by titanium alloy 3D printing could provide enough joint stability and the ability to prevent dislocation.

Effects of radial stress on piezoelectric ceramic tubes and transducers

Static analysis is performed for fiber windings to quantitatively control the radial stress at the outer radius of the piezoelectric ceramic tube. The radial stress is verified both experimentally and theoretically, and the dependence of the resonant and material properties of the piezoelectric ceramic tubes on the radial stress is clarified. The resonance frequencies and dielectric loss remain relatively stable, but the relative permittivity and the short circuit elastic constant decrease with the radial stress. The variations of the increased bandwidth and decreased electromechanical coupling coefficient (k₃₁), piezoelectric constant (d₃₁ and g₃₁), and mechanical quality factor (Q_m) are associated with the height-to-radius ratio. The properties of three cylindrical transducers applied with various radial stress show similar change tendencies, and a difference of 0.34 MPa radial stress results in a variation of approximately 13 in the bandwidth, 14 in Q_m, 15 in k₃₁, d₃₁, and g₃₁, and 16 in the amplitude of the first pulse. These results suggest that the consistency of the radial stress is essential, and it should be relatively small. These findings guide the design and preparation of the enhanced transducer.

Bibliometric Analysis of Research Hotspots Related to Marine Oil Spill Accidents in the Environmental Field Based on Web of Science

Abstract

Objective To conduct bibliometric analysis of the relevant literature in the environmental field published from 1982 to 2018 collected by the Web of Science citation database and further explore the frontier research dynamics and hotspots in the environmental field. Methods The word "oil spill*" was used as the subject term for retrieval. A knowledge map of hotspots in oil spill research was built through software VOSviewer and the clustering relations between them were explored. The frequency and relevance of the keywords in the corresponding literature were obtained by the matrix of keywords built through the Thomson Data Analyzer （TDA） software. Results The four main research hotspots of marine oil spill pollution were oil spill numerical simulation and model prediction, oil spill exposure toxicity and risk assessment, oil spill component and source analysis and oil spill pollution characteristics and treatment. Conclusion The study analyzes the main content of the four research hotspots and the current research progress and provides scientific basis for further understanding of the mechanism of marine oil spill occurrence, migration and transformation, implementation of oil spill treatment and repair as well as more accurate assessment of eco-environment damage.

A nomogram based on pretreatment CT radiomics features for predicting complete response to chemoradiotherapy in patients with esophageal squamous cell cancer

Purpose

To develop and validate a nomogram model to predict complete response (CR) after concurrent chemoradiotherapy (CCRT) in esophageal squamous cell carcinoma (ESCC) patients using pretreatment CT radiomic features.

Methods

Data of patients diagnosed as ESCC and treated with CCRT in Shantou Central Hospital during the period from January 2013 to December 2015 were retrospectively collected. Eligible patients were included in this study and randomize divided into a training set and a validation set after successive screening. The least absolute shrinkage and selection operator (LASSO) with logistic regression to select radiomics features calculating Rad-score in the training set. The logistic regression analysis was performed to identify the predictive clinical factors for developing a nomogram model. The area under the receiver operating characteristic curves (AUC) was used to assess the performance of the predictive nomogram model and decision curve was used to analyze the impact of the nomogram model on clinical treatment decisions.

Results

A total of 226 patients were included and randomly divided into two groups, 160 patients in training set and 66 patients in validation set. After LASSO analysis, seven radiomics features were screened out to develop a radiomics signature Rad-score. The AUC of Rad-score was 0.812 (95% CI 0.742–0.869, p < 0.001) in the training set and 0.744 (95% CI 0.632–0.851, p = 0.003) in the validation set. Multivariate analysis showed that Rad-score and clinical staging were independent predictors of CR status, with p values of 0.035 and 0.023, respectively. A nomogram model incorporating Rad-socre and clinical staging was developed and validated, with an AUC of 0.844 (95% CI 0.779–0.897) in the training set and 0.807 (95% CI 0.691–0.894) in the validation set. Delong test showed that the nomogram model was significantly superior to the clinical staging, with p < 0.001 in the training set and p = 0.026 in the validation set. The decision curve showed that the nomogram model was superior to the clinical staging when the risk threshold was greater than 25%.

Conclusion

We developed and validated a nomogram model for predicting CR status of ESCC patients after CCRT. The nomogram model was combined radiomics signature Rad-score and clinical staging. This model provided us with an economical and simple method for evaluating the response of chemoradiotherapy for patients with ESCC.

[Closed percutaneous reduction and minimally invasive treatment of spastic hammery deformity]

Objective: To investigate the efficacy of percutaneous extensor tendon reconstruction in treating spastic hammery deformity. Methods: From February 2009 to July 2018, the clinicaldata of 36 patients with fresh sputum hammer fingers treated in Jinan People's Hospital were analyzed retrospectively. The tendon was percutaneously sutured with PDS Ⅱmonofilament suture and the distal end of the tendon was fixed to the base of the distal phalanx through the bone hole. Removal of the K-wire 6 weeks after the operation, the brace was used to fix the affected finger in the dorsal extension. For 8-10 weeks, only the brace was worn at night and the flexion and extension of the affected finger was gradually strengthened.The extension and flexion function of the interphalangeal joint of the finger was compared pre and post the operation with t test. Results: A total of 36 patients were enrolled but only 33 patientswere followed up for 6 to 15 months. The hammer-shaped deformity was corrected and there was no pain when moving fingers after the operation.The straightening angle of the interphalangeal joint of the finger improved from 46.2°±6.3° before surgery to 7.5°±0.6° after (t=35.12, P<0.05). The passive straightening angle decreased from 3.2°±0.3° before surgery to 0.9°±0.2° after (t=37.11, P<0.05). According to the Crawford functional assessment: excellent in 19 fingers, good in 10 fingers, can be in 4 fingers. The excellent rate was 87.9%. There was no knot exposure, skin necrosis and other complications. Conclusions: Percutaneous resection of the extensor tendon is fixed in the basal phalanx. It is a simple and feasible minimally invasive surgery for hammer-shaped deformity. It can obviously correct the hammer-shaped deformity and has fewer complications.

[Effect of Hematite on the Inhibition of Hydrogen Sulfide Formation and Its Mechanism During Anaerobic Digestion and Methanogenesis of Sulfate Wastewater]

In order to achieve the high value production of methane, this paper investigated the effect and mechanism of hematite on the inhibitation of the formation of hydrogen sulfide during the anaerobic digestion of high-concentration sulfate wastewater. Different dosages of hematite were added to artificially prepared sulfate wastewater to analyze the migration and transformation pathways of sulfur in the reaction system. The results showed that the delay time of the anaerobic digestion process and the hydrogen sulfide concentration in the control reactor were 1.64 times and 180 times those in the reactor with the optimal hematite dosage of 0.5 g·(30 mL)^-1, respectively. Thus, the addition of hematite effectively shortened the delay time and reduced the concentration of hydrogen sulfide. Dynamic equilibrium analysis of sulfur in different anaerobic digestion reactors showed that the solid sulfur content in the reactor accounted for 96.9% of the total sulfur. XPS results further demonstrated that hematite mainly enhanced the fixation of S^2- in the form of FeS₂. Therefore, the addition of hematite can effectively accelerate the anaerobic digestion of sulfate wastewater while reducing the concentration of hydrogen sulfide in the reactor.

[Preliminary outcomes of percutaneously looped thread transection in the surgical treatment of stenosing tenosynovitis]

Objective: To investigate the percutaneously looped thread transection for treatment of stenosing tenosynovitis and evaluate its treatment outcome. Methods: From January 2014 to October 2016, Eighty-four patients with stenosing tenosynovitis were randomly divided into the open decompressionand group (42 cases) and percutaneously looped thread transection group (42 cases) in Department of Orthopedics, Affiliated Laiwu Hospital of Taishan Medical College. Incision near the digit horizontal stripes, tendon sheath were cut off in the open decompressionand group. Percutaneously looped thread transection was under the guidance of ultrasound, threading from the deep and shallow transverse tendon sheath, respectively, forming loops to cut off and decompressed the flexor tendon. Visual analog scale(VAS) was used to evaluate the extent of pain before the operation and 1 or 4 weeks after the operation, the comprehensive curative effect were evaluated 3 months after the operation. Results: In the two groups pain was alleviated. The VAS improved from (7.0±1.3)prior operation to(5.2±1.6) and (2.8±1.1)1 week and 4 weeks after the operation in the open decompressionand group , respectively. The difference before and after the operation was significant(P<0.05). The VAS improved from (7.1±1.4) prior operation to(2.7±1.3) and (0.6±0.2)1 week and 4 weeks after the operation in the percutaneously looped thread transection group, respectively. The difference before and after the operation was significant(P<0.05). The difference of VAS scores between two groups at 1 week and 4 weeks after the operation were different(P<0.05). The difference of the comprehensive curative effect between two groups at 3 months after the operation were not different(P>0.05). There were no infection, poor healing, blood vessel and nerve damage after operation in both two groups. Conclusion: Percutaneously looped thread transaction under ultrasound for the surgical treatment of stenosing tenosynovitis has less trauma and rapid recovery. It has such advantage as being effective, simple , and reach the same effects as the open decompression surgery.

[Estimation of underreporting rate of death cases in disease surveillance system of Fujian province using propensity score weighting method, 2012-2014]

Objective: To understand the underreporting of death cases and related factors in disease surveillance system of Fujian province. Methods: We carried out a field underreporting survey in 20 disease surveillance sites selected through stratified cluster random sampling during 2012-2014. The related factors of underreporting were analyzed by using logistic regression method. Propensity score weighting method was used to calculate the underreporting rate in different groups classified by year, urban/rural areas, gender, age and death cause variables. Results: The overall underreporting rate was 9.21%(95%CI: 9.06%-9.39%) after adjusting by propensity score weighting method. The underreporting rate was higher in rural area (11.55%, 95%CI: 11.30%-11.81%) than in urban area (6.64%, 95%CI: 6.50%-6.78%). The underreporting rate was highest in age group 0-14 years (36.29%, 95% CI: 34.23%-38.67%) and lowest in age group ≥65 years (7.91%, 95% CI: 7.78%-8.03%). The underreporting rate was higher in people died of perinatal disease, congenital anomalies and injury. Conclusion: The underreporting rates were different between different groups classified by urban/rural areas, age and death cause variables. Propensity score weighting method can be used to adjust underreporting rate of death cases in mortality surveillance in Fujian.

Maternal Question-Asking Behavior to Taiwanese Children with down Syndrome and with No Disability

To study maternal question-asking of Taiwanese children during free play and at meal time each mother-child dyad was videotaped at home. The mothers of children with Down syndrome asked more questions across different types of question during free play, at meal time, and for the sum of these two. Although no group difference was found for producing each type of question during free play, these 20 mothers asked more directive questions at meal time. Combined conditions analysis showed they used more directive questions and fewer requests for clarification than the 20 mothers of children with no disability.

Biomechanical interactions of endodontically treated tooth implant-supported prosthesis under fatigue test with acoustic emission monitoring

BACKGROUND

This study investigated the biomechanical interactions in endodontically treated tooth implant-supported prosthesis (TISP) with implant system variations under dynamic cyclic loads monitored using the acoustic emission (AE) technique.

METHODS

Macrostructure implants using a taper integrated screw-in (TIS; 2-piece implant) and a retaining-screw (RS; 3-piece implant) connected to an abutment were used for this investigation and their corresponding mechanical resistances in conformity with the ISO 14801 standard were evaluated. The endodontically treated TISP samples were constructed containing TIS and RS implants splinted to the second premolar with fatigue tests performed by applying occlusal force onto the premolar simulating the bending moment effect. The numbers of accumulated AE signals in the fatigue tests and failure modes for the sample were recorded to evaluate the mechanical resistance.

RESULT

The maximum load in the static test for RS (3-piece) implant (797N) was significantly higher than that for the TIS (2-piece) implant (559N). Large deformations were found at abutment screws in both RS and TIS implants. Although the numbers of accumulated AE signals for the TIS implant (72511) were higher than those for the RS implant (437), statistical non-significant differences were found between TIS and RS implants. No obvious damage was noted in endodontically treated TISP samples using RS implants but two of the corresponding TIS implants fractured in the abutment screws.

CONCLUSIONS

Splints with RS (3-piece) implant prosthesis produce better mechanical responses than the TIS (2-piece) implant when connected to an endodontically treated tooth restored with a post core and crown.

Mechanical response comparison in an implant overdenture retained by ball attachments on conventional regular and mini dental implants: a finite element analysis

This study investigates the bone/implant mechanical responses in an implant overdenture retained by ball attachments on two conventional regular dental implants (RDI) and four mini dental implants (MDI) using finite element (FE) analysis. Two FE models of overdentures retained by RDIs and MDIs for a mandibular edentulous patient with validation within 6% variation errors were constructed by integrating CT images and CAD system. Bone grafting resulted in 2 mm thickness at the buccal side constructed for the RDIs-supported model to mimic the bone augmentation condition for the atrophic alveolar ridge. Nonlinear hyperelastic material and frictional contact element were used to simulate characteristic of the ball attachment-retained overdentures. The results showed that a denture supported by MDIs presented higher surrounding bone strains than those supported by RDIs under different load conditions. Maximum bone micro strains were up to 6437/2987 and 13323/5856 for MDIs/RDIs under single centric and lateral contacts, respectively. Corresponding values were 4429/2579 and 9557/5774 under multi- centric and lateral contacts, respectively. Bone micro strains increased 2.06 and 1.96-folds under single contact, 2.16 and 2.24-folds under multiple contacts for MDIs and RDIs when lateral to axial loads were compared. The maximum RDIs and MDIs implant stresses in all simulated cases were found by far lower than their yield strength. Overdentures retained using ball attachments on MDIs in poor edentulous bone structure increase the surrounding bone strain over the critical value, thereby damaging the bone when compared to the RDIs. Eliminating the occlusal single contact and oblique load of an implant-retained overdenture reduces the risk for failure.

Association of the IFNAR1-17470 and IL-10-592 cytokine variants with susceptibility to chronic hepatitis B viral infections in a Chinese population

An association between the sequence variants of cytokine genes and various clinical outcomes in subjects infected with the hepatitis B virus (HBV) has been demonstrated. However, the results are inconsistent and inconclusive. Further studies in other populations and the evaluation of a greater number of individuals may contribute to a better understanding of the influence of the cytokine genetic variants on the evolution of HBV infections. This study was performed to explore the relationships between the sequence variants of TNF-A-308, IFNAR1-17470, and IL-10-592 and the susceptibility to chronic hepatitis B (CHB) in a Chinese population. A total of 160 patients with CHB and 124 individuals who had spontaneously recovered (SR) from hepatitis B were enrolled in the present study. The variants at TNF-A-308, IFNAR1-17470, and IL-10-592 were determined by PCR-restriction fragment length polymorphism analysis and were confirmed by bidirectional DNA sequencing. Significant differences were found between the CHB and the SR groups in the frequency and distribution of the genotypes of both IFNAR1-17470 and IL-10-592 genes. In comparison with the CHB patients with the IFNAR1-17470 G/G variant, the odds ratio (OR) of the CHB patients with the IFNAR1-17470 C/C variant developing chronic hepatitis was 2.06 (95%CI = 1.03-4.14). In addition, the OR of the patients with CHB having the IL-10-592 C/C variant developing chronic hepatitis was 2.77 (95%CI = 1.13-4.57) when compared with that of the patients with the IL-10-592 A/A variant. In conclusion, sequence variants of both the IFNAR1-17470 and IL-10-592 genes were correlated with susceptibility to CHB.

Design, manufacture and in-vitro evaluation of a new microvascular anastomotic device

INTRODUCTION

Many microvascular anastomoses have been proposed for use with physical assisted methods, such as cuff, ring-pin, stapler, clip to the anastomose blood vessel. The ring-pin type anastomotic device (e.g., 3M Microvascular Anastomotic System) is the most commonly used worldwide because the anastomotic procedure can be conducted more rapidly and with fewer traumas than using sutures. However, problems including vessel leakage, ring slippage, high cost and high surgical skill demand need to be resolved. The aim of this study is to design and manufacture a new anastomotic device for microvascular anastomosis surgery and validate the device functions with in-vitro testing.

METHODS

The new device includes one pair of pinned rings and a set of semi-automatic flap apparatus designed and made using computer-aided design / computer-aided manufacture program. A pair of pinned rings was used to impale vessel walls and establish fluid communication with rings joined. The semi-automatic flap apparatus was used to assist the surgeon to invert the vessel walls and impale onto each ring pin, then turning the apparatus knob to bring the rings together. The device was revised until it became acceptable for clinical requires. An in-vitro test was performed using a custom-made seepage micro-fluid system to detect the leakage of the anastomotic rings. The variation between input and output flow for microvascular anastomoses was evaluated.

RESULTS

The new microvascular anastomotic device was convenient and easy to use. It requires less time than sutures to invert and impale vessel walls onto the pinned rings using the semi-automatic flap apparatus. The in-vitro test data showed that there were no tears from the joined rings seam during the procedures.

CONCLUSIONS

The new anastomotic devices are effective even with some limitations still remaining. This device can be helpful to simplify the anastomosis procedure and reduce the surgery time.

Temperature and boundary influence on cement hydration monitoring using embedded piezoelectric transducers

In this study, the hydration process was monitored using embedded ultrasonic transducers. It was found that the ultrasonic amplitude decreased and fluctuated at the very early age, several hours after the beginning of fast hydration. The embedded transducers are very different from the surface coupled ones for they were directly influenced by the cement paste, such as the varying temperature and the boundary condition. Experiments were carried out to find out which factor result in such decrease and fluctuation. Test results showed that both the temperature and boundary conditions affect the ultrasonic measurement. When the hydration progressed under constant temperature, the amplitude of the ultrasonic wave decreased smoothly during certain period. When the hardened specimen was tested, it was found that the amplitude would decrease obviously with the increasing of temperature and vice versa. The findings could be used to interpret the amplitude plot obtained in the normal hydration monitoring using embedded transducers.

Finite element sub-modeling analyses of damage to enamel at the incisor enamel/adhesive interface upon de-bonding for different orthodontic bracket bases

This study investigates the micro-mechanical behavior associated with enamel damage at an enamel/adhesive interface for different bracket bases subjected to various detachment forces using 3-D finite element (FE) sub-modeling analysis. Two FE macro-models using triangular and square bracket bases subjected to shear, tensile and torsional de-bonding forces were established using μCT images. Six enamel/adhesive interface sub-models with micro- resin tag morphology and enamel rod arrangement were constructed at the corresponding stress concentrations in macro-model results. The boundary conditions for the sub-models were determined from the macro-model results and applied in sub-modeling analysis. The enamel and resin cement stress concentrations for triangular and square bases were observed at the adhesive bottom towards the occlusal surface under shear force and at the mesial and distal side planes under tensile force. The corresponding areas under torsional force were at the three corners of the adhesive for the triangular base and at the adhesive bottom toward/off the occlusal surface for the square base. In the sub-model analysis, the concentration regions were at the resin tag base and in the region around the etched holes in the enamel. These were perfectly consistent with morphological observations in a parallel in vitro bracket detachment experiment. The critical de-bonding forces damaging the enamel for the square base were lower than those of the triangular base for all detached forces. This study establishes that FE sub-modeling can be used to simulate the stress pattern at the micro-scale enamel/adhesive interface, suggesting that a square base bracket might be better than a triangular bracket. A de-bonding shear force can detach a bracket more easily than any other force with a lower risk of enamel loss.

Biomechanical responses of endodontically treated tooth implant-supported prosthesis

INTRODUCTION

This study was designed to investigate the biomechanical interactions in endodontically treated tooth implant-supported prosthesis with variations in implant system and load type by using the nonlinear finite element (FE) approach.

METHODS

The computed tomography (CT), micro-CT image process, and computer-aided design systems were integrated to construct the FE models containing 1-, 2-, and 3-piece implants splinted to the second premolar. Realistic interface conditions within the implant system were simulated by using frictional contact elements, and mechanical responses in terms of von Mises stress were computed for all models.

RESULTS

The simulated results indicated that splinting an endodontically treated tooth to a neighbor implant decreased stress values in dentin and post but increased stress of implant and bone. The oblique occlusal forces increased the stress values relative to those of axial analogs. A splinted system with a 2-piece implant increased stress on the bone and decreased stress on the prosthesis compared with that of the 1-piece implant.

CONCLUSIONS

Splints with 1-piece implant prosthesis, without eccentric occlusal contacts, have better mechanical responses than those of 2- or 3-piece implants when connected to an endodontically treated tooth restored with post core and crown.

Microcalcification detection in 3-d breast ultrasound

The appearance of cluster of microcalcifications in mammography or sonography is an important indicator for malignancy. Microcalcifications are calcium deposits, which can be identified as tiny areas that are slightly brighter than surrounding tissue. Detection of mammographic microcalcification has been proposed in many studies. Since a microcalcification cluster is a three-dimensional (3-D) entity, its projection onto a two-dimensional (2-D) image results in a loss of spatial information and may also cause superimposition of individual calcifications within the cluster. This paper aims to use the 3-D ultrasound to determine microcalcifications. In each slice, the proposed method adopts the top-hat filter to find bright spots, and employs four 2-D criteria to select the spots as candidate microcalcifications. Finally, spots appearing in sequent slices at the same position are considered as a microcalcification. We suggest using a computer automatically to detect the microcalcification being feasible and microcalcifications being a very important criterion of malignancy on future developing the computer-aided diagnosis for ultrasound. In the future, this technique can be adopted in a computer-aided diagnosis system combined with other diagnosis features for improving the diagnosis performance.

Non-lethal Candida albicans cph1/cph1 efg1/efg1 transcription factor mutant establishing restricted zone of infection in a mouse model of systemic infection

The cph1/cph1 efg1/efg1 Candida albicans mutant cells were non-lethal in a mouse model of systemic infection. We investigated in vivo proliferation and invasion of C. albicans cells in infected mice to elucidate the interaction between the host and the pathogen. Homogenates of kidneys from the mice infected with the wild-type and the mutant C. albicans cells yielded a mean of 2.1 x 10 7 CFU/g and 2.2 x 10 6 CFU/g, respectively. The kidneys from the mice infected with the wild-type cells showed extensive renal cortical necrosis associated with neutrophilic infiltration. There were also wild-type hyphal cells present in abundance. Hence, tubular necrosis leading to renal failure in the mice may be the cause of death. Although the cph1/cph1 efg1/efg1 mutant cells were not lethal, they were capable of establishing restricted zones of infection and colonization near the renal pelvis instead of simply being cleared by the immune system in mice.

Solitary hepatic lymphangioma--a case report

Hepatic lymphangioma is an extremely rare benign neoplasm that is usually associated with lymphangiomas of other viscera. We report a patient with huge, solitary hepatic lymphangioma involving only the liver. The clinical features and computed tomography findings of this case are described.

Bronchoscopic Nd-YAG laser surgery for tracheobronchial mucoepidermoid carcinoma--a report of two cases

Mucoepidermoid carcinoma (MEC) of the tracheobronchial tree represents 0.2% of all lung tumours. It arises from the excretory ducts of the bronchial mucosa and is classified into low- and high-grade tumours using criteria derived from similar tumours of the major salivary glands. Low-grade MEC behaves in a benign fashion with less parenchymal and hilar lymph nodal invasion. The traditional method of treatment is by thoracotomy. The bronchoscopic approach to this lesion using lasers has rarely been reported. This article reports two cases of low-grade tracheobronchial MEC, which were both managed through bronchoscopic neodymium yttrium aluminium garnet (Nd-YAG) laser surgery. The patients were free from disease, 26 and 36 months after surgery. Bronchoscopic laser surgery promises to be an effective alternative treatment modality for tracheobronchial MEC. It is minimally invasive, results in less hospital stay and does not impair pulmonary functions.

Biliary papillary neoplasm of the liver

Biliary papillary neoplasia of the liver characterized by intraductal papillary growth of neoplastic biliary epithelia with a fine fibrovascular stalk has been sporadically reported, and includes intraductal growing cholangiocarcinoma and biliary papillomatosis. In addition, biliary papillary dysplasia and in situ and microinvasive carcinoma with papillary configuration reported in hepatolithiasis and in other chronic biliary diseases, could be included in this category. Usually, they arise in the intrahepatic large bile ducts, and the neoplastic and non-neoplastic parts of the intrahepatic biliary tree show saccular and segmental dilatation with mucin hypersecretion. This neoplasia frequently shows intraductal spreading and peribiliary glandular involvement. Acute repeated episodes of cholangitis or obstructive jaundice are a frequent clinical manifestation. Gastroenteric metaplasia with aberrant expression of cytokeratin 20, MUC2, MUC5AC, and/or MUC6, is frequent in the neoplastic parts, and biliary epithelial dysplasia with such metaplasia may give rise to in situ and then invasive carcinoma in hepatolithiasis. Interestingly, this type tends to contain foci of mucinous carcinoma elements, and this element may be predominant (mucinous carcinoma). Some may progress to "mucinous biliary cystadenocarcinoma" without ovarian mesenchymal stroma and with intraluminal continuous growth into the neighboring bile duct lumens. Interestingly, the biliary papillary neoplasm resembles histologically, phenotypically and clinically intraductal papillary mucinous neoplasm of the pancreas which is now being established as an infrequent, slow-growing pancreatic neoplasm. Recognition of such biliary papillary neoplasm with respect to the pancreatic equivalent may lead to a better understanding and further studies of the intrahepatic biliary neoplasm.

Decomposition of 2-naphthalenesulfonate in aqueous solution by ozonation with UV radiation

This study investigates the ozonation of 2-naphthalenesulfonate (2-NS) combined with ultraviolet (UV) radiation. Naphthalenesulfonic acids are of importance as dye intermediates for the dye and textile auxiliary industries. Its derivatives, such as 2-NS, have been found in rivers and tannery effluents causing pollution problems. Thus, the 2-NS is of concern for the aquatic pollution control especially in the surface and waste waters. Ozonation combined with UV radiation is employed for the removal of 2-NS in the aqueous solution. Semibatch ozonation experiments were proceeded under different reaction conditions to study the effects of ozone dosage and UV radiation on the oxidation of 2-NS. The concentrations of 2-NS and sulfate are analyzed at specified time intervals to elucidate the decomposition of 2-NS. In addition, values of pH and oxidation reduction potential are continuously measured in the course of experiments. Total organic carbon is chosen as a mineralization index of the ozonation of 2-NS. The mineralization of 2-NS via the ozonation is remarkably enhanced by the UV radiation. These results can provide useful information for the proper removal of 2-NS in the aqueous solution by the ozonation with UV radiation.

Prediction of the outcome of pull-through surgery for Hirschsprung's disease using acetylcholinesterase activity

BACKGROUND AND PURPOSE

Advances in surgical procedures for the treatment of Hirschsprung's disease have afforded the majority of patients a satisfactory outcome after definitive corrective surgery. However, some patients continue to have signs of persistent bowel dysfunction despite adequate resection of the aganglionic bowel segment. The definite etiology of persistent bowel dysfunction in these patients remains controversial.

MATERIALS AND METHODS

The acetylcholinesterase activity in the proximal resection margin of pull-through surgical specimens collected from September 1992 to June 1998 was evaluated and correlated with clinical outcome.

RESULTS

A total of 24 patients were studied, 15 males and 9 females. The follow-up period ranged from 1 year 7 months to 7 years 6 months. The Soave procedure was performed in 17 cases and the Duhamel in 7. Twenty cases had a good or fair clinical outcome and four (16.7%) had a poor outcome. There was no mortality. Among the 20 patients with a good or fair outcome, the acetylcholinesterase activity in the proximal section margins was not increased in 12, mildly increased in seven, and moderately increased in one. The four cases with poor outcome all had moderately increased acetylcholinesterase activity in at least one specimen. The association between moderately increased acetylcholinesterase activity and poor surgical outcome was significant (p = 0.0005). In contrast, there was no association between the surgical method (Soave or Duhamel) used and clinical outcome (p = 0.55).

CONCLUSION

Acetylcholinesterase activity in the proximal resection margins of pull-through surgical specimens is a useful indicator for predicting the postoperative outcome in Hirschsprung's disease.

Varied clinical patterns, physical activities, muscle enzymes, electromyographic and histologic findings in patients with post-polio syndrome in Taiwan

STUDY DESIGN

A study of the clinical features, physical activity, muscle enzyme, electromyography and histopathological alternations of muscles in patients with post-polio syndrome (PPS).

OBJECTIVE

To assess the varied patterns of PPS in Taiwan.

SETTING

Taiwan.

METHODS

Thirty-one patients who fulfill the inclusion criteria of PPS were selected for study. Clinical features, physical activity scale, serum concentrations of creatine kinase, electromyography and histopathological alterations of muscles were assessed and correlated to the causes of PPS patients.

RESULTS

Patients with PPS in Taiwan are relatively young, with a mean age of 39.3 years. Elevated concentration of creatine kinase was found predominantly in male patients with higher physical activities. Electromyographic examinations as well as histological tests of affected muscles revealed prominent evidence of chronic and active denervation with reinnervation in PPS patients.

CONCLUSION

Patients with PPS in Taiwan are young. Thus, PPS should not be attributed to aging. Physical attrition with degradation of nerve terminals is considered the main cause of this disease.

SPONSORSHIP

This study was supported by the National Science Council, Republic of China under grant no. NSC-83-0412-B002-302.

Cytomegalovirus infection and proinflammatory cytokine activation modulate the surface immune determinant expression and immunogenicity of cultured murine extrahepatic bile duct epithelial cells

Murine extrahepatic bile duct epithelial cells (MEBEC) were isolated from extrahepatic bile ducts of BALB/c mice and established in primary culture. The epithelial origin was confirmed by positive cytokeratin 19 staining for these cells and the presence of microvilli and tight junctions under electron microscopy. By immunofluorescent staining with monoclonal antibodies and flow-cytometric analysis, MEBEC in culture constitutively express low levels of intercellular adhesion molecule (ICAM)-1, class I and class II major histocompatibility (MHC) antigens. The expression of ICAM-1 was significantly increased by interferon gamma (INF-gamma) or tumour necrosis factor alpha (TNF-alpha) stimulation. Class I and class II antigen expression were significantly enhanced by INF-gamma and in vitro murine cytomegalovirus (MCMV) infection. MEBEC infected with MCMV revealed a progressive cytopathic effect. MEBEC activated by INF-gamma or infected by MCMV induced a low but significant proliferation of allogeneic T cells and displayed a significant decrease in the absorbance at O.D. 550 nm in a microtitre tetrazolium assay after these treated cells were co-cultured with allogeneic T cells. These results suggest that following the up-regulation of surface MHC antigen and adhesion molecule expression with cytokines or MCMV, the MEBEC can function as antigen-presenting cells and initiate T-cell proliferation, which in turn trigger the recognition of MEBEC by effector T-cell-mediated cytotoxic responses. These findings may be implicated in the pathogenesis of virally induced, immune-mediated extrahepatic bile duct damage disorders.

Maternal question-asking of Japanese children with Down syndrome and with no disability

In an extension of maternal question-asking to Japanese children during free play and at meal time each of 20 mother-child dyads was videotaped at home. The mothers of children with Down syndrome asked more questions during free play at meal time, and for the sum of these two. Also, they produced more requests for information during free play and for combined conditions and fewer clarification requests during free play. The results were compared to those of the previous study of Taiwanese mothers.

Langerhans' cell histiocytosis presenting with a para-aortic lesion and heart failure

Langerhans' cell histiocytosis (LCH) is an uncommon disease with variable manifestations. We report a case of LCH with the unusual initial presentations of chest pain and progressive heart failure in a 5-year-old boy. Chest radiography revealed a wide mediastinum with cardiomegaly. Electrocardiography showed first-degree atrioventricular block and an inverted T wave over V4-V6. Echocardiography, computed tomography, and magnetic resonance imaging of the chest all showed an infiltrating lesion that enveloped the entire heart, great vessels, and coronary arteries. Pathologic examination of the biopsy specimen revealed LCH. Chemotherapy, which included prednisolone, vincristine, methotrexate, and 6-mercaptopurine, had only a minimal effect on the tumor. After the addition of etoposide, the lesion decreased in size, and the symptoms and signs of heart failure and chest pain were ameliorated.

Focal nodular hyperplasia of the liver in a child

We present a case of focal nodular hyperplasia (FNH) of the liver in a 7-year-old girl. The hepatic tumor was found incidentally on physical examination at school. During surgery, a hypervascular mass with a nodular surface was found to be confined to the right lobe of the liver (mainly in segments 5 and 6). The brownish tumor and the gallbladder were completely removed. Pathologic examination revealed a 10 x 9 x 5-cm mass with a central scar and radiating septa, consistent with the diagnosis of FNH. The postoperative course was complicated by subhepatic effusion, which was resolved by percutaneous computed tomography-guided drainage. She remained well 2 years after surgery.

Congenital interstitial cell of cajal hyperplasia with neuronal intestinal dysplasia

Interstitial cells of Cajal (ICCs) are intestinal pacemaker cells that initiate peristalsis in the stomach and intestine, and are considered to be precursors of gastrointestinal stromal tumors (GISTs). We report a 2-year-old girl who suffered from scanty stool passage since birth. On barium enema, the distal colon was rigid with narrow lumen, whereas the proximal colon was dilated and atonic. She received right hemicolectomy and ileostomy. Histopathologically, there was continuous proliferation of spindle cells located between the layers of the muscularis propria throughout the right colon. These spindle cells were positive for c-kit and CD34 but negative for myogenic or neurogenic markers, indicating they are ICCs. No germline or somatic mutation of the juxtamembrane domain of c-kit gene was detected. In addition, the changes of the submucosal plexus fulfilled the histologic criteria of neuronal intestinal dysplasia type B. To our knowledge, this is the first reported case of congenital ICC hyperplasia. Further studies of ICC development may contribute to better understanding of the pathogenesis of this congenital malformation and the tumorigenesis of GIST.

Antenatal diagnosis of congenital hepatoblastoma in utero

A fetus with a huge hepatic tumor was detected by sonography at 36 weeks of gestation. The mass appeared as a single, solid and polylobular tumor located in the right lobe of the liver. Foci of hemorrhage, necrosis and some tiny calcifications were seen. The adjacent right kidney appeared normal but was displaced. The right adrenal gland was not visualized. Three-dimensional power Doppler sonography further depicted the corresponding vascular anatomy of the tumor, including its vascularization pattern and blood supply. The tumor was situated to the right of the umbilical vein and portal sinus, possibly deriving its blood supply from the portal circulation. The fundamental findings suggested the diagnosis of hepatoblastoma by exclusion of other possibilities. The baby was delivered by Cesarean section at 36 weeks' gestation, due to signs of fetal distress. Unfortunately, hypotension, tachycardia, and tachypnea developed shortly after birth. Surgical intervention was performed, but intractable bleeding occurred intra-operatively. The infant died at 6 days of age. Autopsy confirmed the diagnosis of hepatoblastoma. We believe this is the first reported case of the antenatal diagnosis of congenital hepatoblastoma.

[The treatment of severe complications of laparoscopic cholecystectomy]

The treatment of 24 cases of severe complications of laparoscopic cholecystectomy (LC) in 1993-1998 is reported. Among them, 16 cases were from the other hospitals. The patients included 14 cases of bile duct injury, 3 cases of bile leak, 1 case of duodenal injury, 5 cases intraoperative hemorrhages, 1 case mediastinal emphysema. The data showed that bile duct injury was the most severe complication of LC. It is suggested that in order to prevent the complications a training of operators on adaptive exercise and standard intraoperative procedure should be undertaken. The diagnosis and treatment of severe complications are discussed and some useful advice is given in this paper.

Accurate diagnosis of Helicobacter pylori infection by stool antigen test and 6 other currently available tests in children

Invasive and noninvasive tests have been developed for the diagnosis of Helicobacter pylori infection. Because H pylori infection is acquired in childhood and adolescence, accurate diagnosis of the infection in the pediatric population is important. We conducted a study to compare invasive tests: culture, biopsy urease test, histology, and polymerase chain reaction on gastric biopsy specimens, with noninvasive tests: serology, (13)C-urea breath test, and a new diagnostic modality, stool antigen test to diagnose H pylori infection. A total of 53 children with symptoms were enrolled in this study, and all had completed the 7 diagnostic tests for H pylori. All the diagnostic tests except serology were excellent methods of diagnosing H pylori infection in children; the diagnostic accuracy was as follows: stool antigen test 96.2%, biopsy urease test 96.2%, histology 98.1%, polymerase chain reaction 94.3%, culture 98.1%, (13)C-urea breath test 100%, and serology 84.9%. The stool antigen test, being highly sensitive and specific, will be potentially very helpful in diagnosing H pylori infection in children.

Spontaneous bowel perforation in infants and young children: a clinicopathologic analysis of pathogenesis

BACKGROUND

In children beyond the neonatal stage, spontaneous bowel perforation with no specific cause is rare. It has attracted little notice and does not fit into any established clinical category. This often results in treatment delays. To determine the underlying pathogenesis, a clinicopathologic analysis of this group of patients was performed.

METHODS

From 1984 through 1997, 15 previously healthy children (10 boys and 5 girls) with bowel perforations were enrolled in this study. Children in whom the specific cause was established were excluded. The ages of the patients ranged from 3 months to 5 years, 5 months (average age: 2 years, 4 months). Data on clinical course, surgical and pathologic findings, and outcomes were analyzed.

RESULTS

All the patients had high fever and acute, watery diarrhea with clinical dehydration. Abdominal distension developed and bowel perforation ensued 5 to 30 days after the onset of diarrhea. In all cases, the perforation consisted of either an isolated patch of bowel (n = 8) or patchy lesions in a segment (n = 7), which was confined to one of the following three anatomic watershed areas: the splenic flexure (n = 7); the lower sigmoid (n = 3); and the ileocecal region (n = 5). One patient died, and three had major sequelae including intra-abdominal abscess, adhesion ileus, and peristomal fistula. Specimens from 13 patients were submitted for histopathologic evaluation. All specimens had acute suppurative inflammation diffusely around the perforation site. Seven had areas of coagulation necrosis of the muscularis propria, especially in the inner circular muscle layer.

CONCLUSION

In acute diarrheal diseases, dehydration may cause bowel ischemia and lead to perforation. Physicians should be alert to the possibility of this abdominal catastrophe when progressive abdominal distension followed by acute diarrheal episodes occurs in children.

Metabolic disorders mimicking Reye's syndrome

BACKGROUND

Several metabolic disorders such as encephalopathy and hepatic dysfunction have been described as Reye's-like syndrome because they present with similar clinical manifestations that mimic Reye's syndrome. We performed a retrospective study to explore the underlying metabolic etiologies of Reye's-like syndrome in patients treated at National Taiwan University Hospital.

METHODS

From January 1991 to June 1998, 19 children with a syndrome fitting the Reye's-like syndrome description were identified for study. Urine organic acid analysis, plasma amino acid analysis, liver pathology, and skin fibroblast enzyme assays were studied during the acute stage of illness.

RESULTS

The etiologies of patients' syndromes included urea cycle disorders (n = 7), glycogen storage disease type Ia (4), primary carnitine deficiency (2), hereditary fructose intolerance (1), methylmalonic acidemia (2), and 3-hydroxy-3-methylglutaric acidemia (1). Fatty acid oxidation defects were suspected in the remaining two cases.

CONCLUSIONS

A significant number of patients who present with Reye's-like syndrome have an underlying inherited metabolic disorder. In patients with Reye's-like syndrome, an accurate diagnosis is essential to ensure normal growth and development and to prevent recurrence of the condition.

Allelic loss at chromosome band 6q14 correlates with favorable prognosis in hepatocellular carcinoma

Cytogenetic and molecular studies have frequently shown chromosome 6q deletions in non-Hodgkin lymphoma and several human cancers. There have been few studies concerning chromosome 6q deletion in hepatocellular carcinoma (HCC), and most of these studies have focused on region 6q26-27. We previously described frequent allelic loss at 6q14 in HCC. As a step toward narrowing the scope of search for tumor suppressor genes, we used a series of yeast artificial chromosome clones that map to the long arm of chromosome 6 (6q14-6q22) by fluorescence in situ hybridization (FISH) to define the minimal common region of allelic loss in 25 cases of HCC. Altogether, 12 tumors had allelic loss on 6q (48%). Eleven of the 12 tumors had polysomy of chromosome 6 with evident intratumor cytogenetic heterogeneity. The minimal common region of allelic loss lies within a 2-cM region at 6q14, flanked by D6S458 (849_d_8) and D6S275 (911_a_3). Clinicopathologic correlation between the 12 patients with allelic loss at 6q and the 13 patients without allelic loss showed no significant differences in any basic characteristics except survival. Patients with allelic loss at 6q had a much longer median survival time than those without allelic loss (50 months vs. 11 months, P = 0.0019). Only 5 of the 25 HCC patients were still alive at the time of this study, and all of them had allelic loss at 6q, which is also statistically significant (P = 0.037, alive vs. dead). The association of allelic loss at 6q with polysomy implies that this may be a progression-associated event in HCC. The correlation of allelic loss at 6q with long survival suggests a complex mechanism of tumorigenesis in HCC and is worthy of further investigation.

Phenotypic heterogeneity in a Chinese family with mitochondrial disease and A3243G mutation of mitochondrial DNA

The A3243G mutation of mitochondrial DNA (mtDNA) has been shown to be responsible for or associated with mitochondrial myopathy, encephalopathy, lactic acidosis, strokelike episodes (MELAS) syndrome, diabetes mellitus (DM) and several other neuromuscular diseases. We used polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) to identify the A3243G mtDNA mutation and an electron microscope to examine mitochondrial derangement in the muscle biopsies of a 38-year-old man suspected to have MELAS syndrome with DM. We found great variability in the clinical presentation and in the proportion of mtDNA with the A3243G mutation in the matrilineal family members of the patient. The proband had atypical MELAS syndrome, recurrent vascular headache, and DM (MELASDM), and his mother manifested chronic progressive ptosis and DM (CPPDM). Brain magnetic resonance imaging of the proband showed high signal intensity in the left temporoparieto-occipital area on T2 weighted images (T2WI). The blood lactate level ranged from 2.32 to 4.70 mmol/l, and two-hour postprandial glucose ranged from 124 mg/dl to 148 mg/dl. The blood lactate and postprandial glucose of the proband's mother were 3.15 mmol/l and 192 mg/dl, respectively. Electron microscopic examination of a muscle biopsy of the patient showed abnormal mitochondria with decreased density of cristae and membrane degeneration. No ragged-red fibers were detected in muscle upon staining with modified Gomori trichrome. The hair follicles and blood cells of the patient and his mother showed the A3243G mutation in the tRNA(Leu)(UUR) gene. The proportions of the mutant DNA in the hair follicles and blood cells of the proband were 36.8% and 35.2%, respectively, and those of the patient's mother were 28.8% and 13.9%, respectively. We conclude that the A3243G mtDNA mutation may manifest with MELASDM or CPPDM in different matrilineal members of the same family as a result of differences in random segregation of the heteroplasmic A3243G mutant mtDNA in the affected tissues of patients.