Arsenic exposure in northern Mexican women / Exposición a arsénico en mujeres del norte de México

Abstract: Objective: To describe interindividual metabolism variations and sociodemographic characteristics associated to urinary arsenic, and to estimate the arsenic contamination in water from urinary total arsenic (TAs). Materials and methods: Women (n=1 028) from northern Mexico were interviewed about their sociodemographic characteristics and their urinary concentrations of arsenic species were measured by liquid chromatography. Inorganic arsenic (iAs) in water was estimated from urinary TAs. Results: Women were 20-88 years old. TAs in urine ranged from p10=3.41 to p90=56.93 μg/L; 74% of women had levels >6.4 μg/L. iAs in water varied from p10=3.04 to p90=202.12 μg/L; 65% of women had concentrations >10 μg/L, and 41%, concentrations >25 μg/L. Large variations in iAs metabolism were observed. TAs was significantly negatively associated with age and schooling, and positively with the state of residence. Conclusion: Exposure to iAs is an environmental problem in Mexico. Individual variations in metabolism are a challenge to design prevention and control programs.

Resumen: Objetivo: Describir las variaciones interindividuales del metabolismo y las características sociodemográficas asociadas con el arsénico urinario, así como estimar su contaminación en el agua. Material y métodos. Se entrevistó a 1 028 mujeres del norte de México; por cromatografía de líquidos se midieron los metabolitos urinarios de arsénico y, a partir de ellos, se estimó la concentración en agua. Resultados: Las mujeres tuvieron 20-88 años. El arsénico urinario varió de p10=3.41 a p90=56.93 μg/L; 74% de las mujeres tuvieron niveles >6.4 μg/L. El arsénico en agua varió de p10=3.04 a p90=202.12 μg/L; 65% de las mujeres tenían concentraciones >10 μg/L, y 41%, >25 μg/L. Se observaron amplias variaciones en el metabolismo del arsénico. El arsénico urinario se asoció negativamente con la edad y escolaridad, y positivamente con el estado de residencia. Conclusión: La exposición a arsénico es un problema ambiental en México. Las variaciones individuales en su metabolismo son un desafío para diseñar programas de prevención y control.

Urinary arsenic species concentration in residents living near abandoned metal mines in South Korea

BACKGROUND: Arsenic is a carcinogenic heavy metal that has a species-dependent health effects and abandoned metal mines are a source of significant arsenic exposure. Therefore, the aims of this study were to analyze urinary arsenic species and their concentration in residents living near abandoned metal mines and to monitor the environmental health effects of abandoned metal mines in Korea. METHODS: This study was performed in 2014 to assess urinary arsenic excretion patterns of residents living near abandoned metal mines in South Korea. Demographic data such as gender, age, mine working history, period of residency, dietary patterns, smoking and alcohol use, and type of potable water consumed were obtaining using a questionnaire. Informed consent was also obtained from all study subjects (n = 119). Urinary arsenic species were quantified using high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP/MS). RESULTS: The geometric mean of urinary arsenic (sum of dimethylarsinic acid, monomethylarsonic acid, As3+, and As5+) concentration was determined to be 131.98 μg/L (geometric mean; 95% CI, 116.72–149.23) while urinary inorganic arsenic (As3+ and As5+) concentration was 0.81 μg/L (95% CI, 0.53–1.23). 66.3% (n = 79) and 21.8% (n = 26) of these samples exceeded ATSDR reference values for urinary arsenic (>100 μg/L) and inorganic arsenic (>10 μg/L), respectively. Mean urinary arsenic concentrations (geometric mean, GM) were higher in women then in men, and increased with age. Of the five regions evaluated, while four regions had inorganic arsenic concentrations less than 0.40 μg/L, one region showed a significantly higher concentration (GM 15.48 μg/L; 95% CI, 7.51–31.91) which investigates further studies to identify etiological factors. CONCLUSION: We propose that the observed elevation in urinary arsenic concentration in residents living near abandoned metal mines may be due to environmental contamination from the abandoned metal mine. TRIAL REGISTRATION: Not Applicable (We do not have health care intervention on human participants).

Changes in mRNA expression of p53 and related downstream genes in peripheral blood lymphocytes in workers occupationally exposed to arsenic / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the changes in mRNA expression of p53 and related downstream genes in peripheral blood lymphocytes in workers occupationally exposed to arsenic as well as its influencing factors, and to analyze the mechanism of genetic toxicity of arsenic.</p><p><b>METHODS</b>With cluster random sampling, 79 workers from an arsenic smelting plant were selected as exposure group, and another 24 people without occupational exposure to arsenic were selected as control group. The relative mRNA expression of p53 and related downstream genes in the peripheral blood lymphocytes of the two groups was determined by quantitative realtime PCR. The levels of inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in urine were determined by hydride generation-atomic absorption spectrometry.</p><p><b>RESULTS</b>The exposure group had significantly higher levels of iAs, MMA, and DMA than the control group (P<0.01); the exposure group had significantly higher relative mRNA expression (2(-ΔΔCt)) of p53 and four related downstream genes in peripheral blood lymphocytes than the control group (P<0.05); the relative mRNA expression of p53 and related downstream genes was positively correlated with each other (P<0.01), with a correlation coefficient greater than 0.4; the levels of arsenic compounds in urine were positively correlated with the relative mRNA expression of p53 and some of its downstream genes (P<0.05).</p><p><b>CONCLUSION</b>The changes in mRNA expression of p53 and related downstream genes are closely related to the metabolic transformation of inorganic arsenic in workers occupationally exposed to arsenic, and it also plays an important role in genetic toxicity and carcinogenic effect in people exposed to arsenic.</p>

Autocuidado do cuidador familiar de adultos ou idosos dependentes após a alta hospitalar / Self-care in family caregiver of dependent adults or elderly persons after hospital discharge / El autocuidado del cuidador familiar de adultos o ancianos dependientes tras el alta hospitalaria

Este artigo apresenta uma compreensão sobre o autocuidado do cuidador familiar segundo a teoria de Dorothea Orem. Resulta de uma pesquisa qualitativa com aporte da Teoria Fundamentada nos Dados, utilizando-se das técnicas de visita domiciliar, registro de notas de campo e entrevista semiestruturada com 11 cuidadores, após a internação de familiar em um Hospital Universitário de Minas Gerais. Foram obtidas quatro categorias, destacando uma categoria central, em torno da qual se analisaram as facilidades, dificuldades e estratégias para o autocuidado do cuidador. Entre as dificuldades, foram evidenciadas: tempo insuficiente para os cuidados com a saúde e, entre as facilidades, o apoio de outros familiares. As principais estratégias foram: apoio na fé; revezamento nos cuidados e recursos na comunidade. Concluiu-se que orientações no momento da alta e o acompanhamento de enfermagem após a alta contribuem para o autocuidado do cuidador, atuando sobre suas dificuldades e estimulando suas potencialidades.

This article presents an understanding concerning self-care in family caregivers according to Dorothea Orem's theory. Resulting from a qualitative research based on Grounded Theory, this work uses the techniques of home visiting, field notes and semistructured interviews with 11 caregivers after the hospitalization of a family member in a teaching Hospital located in Minas Gerais. Four categories were found and among them a central category is highlighted from which some facilities, difficulties and strategies for selfcare in caregiver were analyzed. Considering the difficulties, insufficient time for healthcare was noticed whereas the support from other family members appeared as a facility. The main strategies were: faith as a support; shift work in healthcare and community resources. This study demonstrated that hospital discharge guidelines and nursing follow-up after discharge were responsible for positive contributions to self-care in caregivers helping them to overcome their difficulties and enhancing their potentialities.

El artículo presenta una comprensión sobre el autocuidado del cuidador familiar, según la teoría de Dorothea Orem. Resulta de investigación cualitativa con aporte de la Teoría Fundamentada en los Datos, utilizándo se de las técnicas de visitas a domicilio; registro de apuntes de campo y entrevista semiestructurada, tras la internación de un familiar en un hospital universitario de Minas Gerais. Se llegó a cuatro categorías, señalando una categoría central, alrededor de la cual se analizaron las facilidades, dificultades y estrategias para el autocuidado del cuidador. Se evidenció, entre las dificultades, tiempo insuficiente para los cuidados con la salud y, entre las facilidades, el apoyo de otros familiares. Las principales estrategias fueron: apoyo en la fe, revezo en los cuidados y recursos en la comunidad. Se concluyó que orientaciones el momento del alta y el acompañamiento de enfermería tras el alta contribuyen para el autocuidado del cuidador, actuando sobre sus dificultades y estimulando sus potencialidades.

The separation of arsenic metabolites in urine by high performance liquid chromatographyinductively coupled plasma-mass spectrometry

OBJECTIVES: The purpose of this study was to determine a separation method for each arsenic metabolite in urine by using a high performance liquid chromatography (HPLC)- inductively coupled plasma-mass spectrometer (ICP-MS). METHODS: Separation of the arsenic metabolites was conducted in urine by using a polymeric anion-exchange (Hamilton PRP X-100, 4.6 mm x 150 mm, 5 mum) column on Agilent Technologies 1260 Infinity LC system coupled to Agilent Technologies 7700 series ICP/MS equipment using argon as the plasma gas. RESULTS: All five important arsenic metabolites in urine were separated within 16 minutes in the order of arsenobetaine, arsenite, dimethylarsinate, monomethylarsonate and arsenate with detection limits ranging from 0.15 to 0.27 mug/L (40 muL injection). We used GEQUAS No. 52, the German external quality assessment scheme and standard reference material 2669, National Institute of Standard and Technology, to validate our analyses. CONCLUSIONS: The method for separation of arsenic metabolites in urine was established by using HPLC-ICP-MS. This method contributes to the evaluation of arsenic exposure, health effect assessment and other bio-monitoring studies for arsenic exposure in South Korea.

The molecular mechanism of interaction of trivalent dimethylarsinous acid (DMA(III)) binding to rat hemoglobin / 药学学报

In our previous work, we found that trivalent dimethylarsinous acid (DMA(III)) have high affinity binding to cysteine residue 13 of rat hemoglobin. However, it is still unknown why arsenic intermediate metabolite DMA(III) has high binding affinity for Cysl3 but not for other cysteine residues 93, 140, 111 and 125. In order to better understand the molecular mechanism of DMA(III) with rat hemoglobin, we have done current study. So, SD rats were divided into control and arsenic-treated groups randomly. Arsenic species in lysate of red blood cells were analyzed by HPLC-ICP-MS, and then determined by a hybrid quadrupole TOF MS. In addition, trivalent DMA(III) binds to different cysteine residues in rat hemoglobin alpha and beta chains were also simulated by Molecular Docking. Only Cys13 in alpha chain is able to bind to DMA(III) from the experiment results. Cys13 of alpha chain in rat hemoglobin is a specific binding site for DMA(III), and we found that amino acids compose pockets structure and surround Cys13 (but not other cysteine residues), make DMA(III) much easy to bind cysteine 13. Taken together, the DMA(III) specific binding to Cys13 is related to spatial structure of Cys13.

Assessment of Arsenic Exposure by Measurement of Urinary Speciated Inorganic Arsenic Metabolites in Workers in a Semiconductor Manufacturing Plant

OBJECTIVES: The purpose of this study was to evaluate the exposure to arsenic in preventive maintenance (PM) engineers in a semiconductor industry by detecting speciated inorganic arsenic metabolites in the urine. METHODS: The exposed group included 8 PM engineers from the clean process area and 13 PM engineers from the ion implantation process area; the non-exposed group consisted of 14 office workers from another company who were not occupationally exposed to arsenic. A spot urine specimen was collected from each participant for the detection and measurement of speciated inorganic arsenic metabolites. Metabolites were separated by high performance liquid chromatography-inductively coupled plasma spectrometry-mass spectrometry. RESULTS: Urinary arsenic metabolite concentrations were 1.73 g/L, 0.76 g/L, 3.45 g/L, 43.65 g/L, and 51.32 g/L for trivalent arsenic (As3+), pentavalent arsenic (As5+), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and total inorganic arsenic metabolites (As3+ + As5+ + MMA + DMA), respectively, in clean process PM engineers. In ion implantation process PM engineers, the concentrations were 1.74 g/L, 0.39 g/L, 3.08 g/L, 23.17 g/L, 28.92 g/L for As3+, As5+, MMA, DMA, and total inorganic arsenic metabolites, respectively. Levels of urinary As3+, As5+, MMA, and total inorganic arsenic metabolites in clean process PM engineers were significantly higher than that in the non-exposed group. Urinary As3+ and As5+ levels in ion implantation process PM engineers were significantly higher than that in non-exposed group. CONCLUSION: Levels of urinary arsenic metabolites in PM engineers from the clean process and ion implantation process areas were higher than that in office workers. For a complete assessment of arsenic exposure in the semiconductor industry, further studies are needed.

Urinary Arsenic Concentrations and their Associated Factors in Korean Adults

Arsenic (As) is a well-known human carcinogen and its dietary exposure has been found to be the major route of entry into general population. This study was performed to assess the body levels of As and their associated factors in Korean adults by analyzing total As in urine. Urine and blood samples were collected from 580 adults aged 20 years and older, who had not been exposed to As occupationally. Demographic information was collected with the help of a standard questionnaire, including age, smoking, alcohol intake, job profiles, and diet consumed in the last 24 hrs of the study. Total As, sum of As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), in urine was determined using atomic absorption spectrometer involving hydride generation method. The geometric mean concentration of total As in urine was 7.10 microg/L. Urine As was significantly higher in men (7.63 microg/L) than in women (6.75 microg/L). Age, smoking, alcohol consumption, and job profiles of study subjects did not significantly affect the concentration of As in urine. No significant relationship was observed between body mass index (BMI), Fe, and total cholesterol in serum and urinary As. Urine As level was positively correlated with seaweeds, fishes & shellfishes, and grain intake. A negative correlation between urinary As level and HDL-cholesterol in serum and meat intake was observed. Overall, these results suggest that urinary As concentration could be affected by seafood consumption. Therefore, people who frequently consume seafood and grain need to be monitored for chronic dietary As exposure.

Changes in the Testis Interstitium of Rabbits from Birth to Sexual Maturity / 체질인류학회지

Changes in the testis interstitium from birth to adulthood were studied in New Zealand white rabbits of 1, 7, 21, 35, 49, 70, 105, 147, 196, and 252 days (n=8 per group) of age. Testes of rabbits were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 microm sections stained with methylene blueazure II, qualitative and quantitative (stereological) morphological studies were performed. Sperm production was measured by routine technique. The volume density of the interstitium represents 66.3% of the testicular parenchyma at day 1. Adult Leydig cells initially detected at day 7 (0.001%), increased progressively to reach a volume density of 2.6% by day 252. The absolute volume of mesenchymal cells, endothelial cells, pericytes, and myoid cells increased from birth to 252 days. The number of endothelial cells, pericytes, and myoid cells per testis increased gradually with age. The absolute numbers of adult Leydig cells and mesenchymal cells per testis increased linearly from birth to 252 days. The rate of production of adult Leydig cells was greater than that of mesenchymal cells in the postnatal rabbit testis through 252 days. The average volume of a mesenchymal cell increased from day 1 to day 70 and declined thereafter; the highest value was at day 70. Total sperm production and daily sperm production per testis increased significantly from 105 to 252 days of age. These results clarified the pattern of changes in the testis interstitium in rabbits from birth to adulthood and correlation these events with spermatogenesis.

Changes in the Testis Interstitium of Rabbits from Birth to Sexual Maturity / 체질인류학회지

Changes in the testis interstitium from birth to adulthood were studied in New Zealand white rabbits of 1, 7, 21, 35, 49, 70, 105, 147, 196, and 252 days (n=8 per group) of age. Testes of rabbits were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 microm sections stained with methylene blueazure II, qualitative and quantitative (stereological) morphological studies were performed. Sperm production was measured by routine technique. The volume density of the interstitium represents 66.3% of the testicular parenchyma at day 1. Adult Leydig cells initially detected at day 7 (0.001%), increased progressively to reach a volume density of 2.6% by day 252. The absolute volume of mesenchymal cells, endothelial cells, pericytes, and myoid cells increased from birth to 252 days. The number of endothelial cells, pericytes, and myoid cells per testis increased gradually with age. The absolute numbers of adult Leydig cells and mesenchymal cells per testis increased linearly from birth to 252 days. The rate of production of adult Leydig cells was greater than that of mesenchymal cells in the postnatal rabbit testis through 252 days. The average volume of a mesenchymal cell increased from day 1 to day 70 and declined thereafter; the highest value was at day 70. Total sperm production and daily sperm production per testis increased significantly from 105 to 252 days of age. These results clarified the pattern of changes in the testis interstitium in rabbits from birth to adulthood and correlation these events with spermatogenesis.

Morphometric Studies in the Leydig Cell of Hemicastrated Rats / 체질인류학회지

The present study was conducted to investigate the influence of hemicastration and age at hemicastraion on the subsequent Leydig cell morphology and function of male rats. Sprague Dawley rats were left intact or hemicastrated at 20, 30, 40, 50, or 60 days of age (n=18 rats per group). At 100 days of age, all rats were sacrificed. Testes were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 micrometer sections stained with methylene blue, qualitative and quantitative morphological studies were performed. Testis incubations were used to determine lutenizing hormone (LH; 100 ng/mL) stimulated testosterone secretory capacity per testis in vitro. Testosterone levels in the incubation medium, and testosterone and LH levels in serum of these six groups of rats were determined by radioimmunoassay. Body and testis weights were not changed by hemicastration between experimental and control groups. Volume density of seminiferous tubules, interstitium, and Leydig cells was not significantly affected by hemicastration. Absolute volume of seminiferous and interstitium was significantly increased in unilaterally castrated rats at 20, 30 and 40 days of age compared to control. Significant increases in the total number of Leydig cells per testis occurred in rats hemicastrated at 20, 30, 40 and 50 days of age compared to control. A significant increase in average volume of a Leydig cell was noted in the hemicastrated rats at 30 and 40 days compared to intact rats of the same age but was significantly decreased at 60 days of age. Serum testosterone levels and LH-stimulated testosterone production per testis were significantly (P<0.05) increased in the hemicastrated rats at 30 and 40 days. In summary, when rats were unilaterally castrated at 20, 30, 40, 50, and 60 days of age, those rats hemicastrated at 30 and 40 days showed compensatory hypertrophy/hypersecretion of Leydig cells when killed at 100 days of age. Especially, these data suggested that compensatory hypertrophy/hypersecretion of Leydig cells in rats hemicastrated around the time of puberty occurs in the remaining testis.

The Effect of Myocardial Infarction on the Reproductive Function in Adult Male Rats / 체질인류학회지

The present study was to investigate in more detail the changes of reproductive function in the male rat following myocardial infarction (MI). Ligation of the left coronary artery was performed in male Sprague-Dawley male rats at 60 days of age. Control rats were obtained sham-operated animals. MI rats were sacrificed at 1, 3, 5, 7, 14, and 30 day after ligation of left anterior descending coronary artery. Control rats were sacrificed on 30 day after thoracotomy. Myocardial infarct size was assessed by planimetry and perimetry. Testes of rats were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 micro sections stained with methylene blue-azure II, qualitative and quantitative (stereological) morphological studies were performed. Testosterone levels in the incubation medium of luteinizing hormone-stimulated (100 ng/mL) testosterone secretion per testis in vitro, and in serum were determined by radioimmunoassay. Sperm production was measured by routine technique. Mean infarct size was 29.5~33.5% of the left ventricle after coronary occlusion in experimental groups. No changes were observed in testis volume, absolute volume of Leydig cell, Leydig cell size, and number of Leydig cell per testis in MI rats compared to sham-operated animals. Serum testosterone, LH-stimulated testicular testosterone production, and daily sperm production in MI rats were not significantly different (P>0.05) from sham-operated animals. These results demonstrate that under the experimental conditions employed here, experimental chronic myocardial infarction does not exert adverse effects on the reproductive function of male rats.

Aging Effect on the Morphology of the Otoconia Using Scanning Electron Microscopy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Displaced otoconia in the semicircular canal from senile otoconial degeneration have been believed as a major cause of benign paroxysmal positional vertigo (BPPV). The otoconia are mainly composed of calcium carbonate, and thus they are susceptible to chemical deformation during the usual process of scanning electron microscopy (SEM). The aims of this study were to present an optimal protocol of otoconial preparation for SEM and to investigate the change of otoconial morphology due to aging. SUBJECTS AND METHOD: The macula in mice were dissected free from the temporal bone and were divided into three groups using different fixatives and buffers: 2.5% glutaraldehyde in phosphate buffer, 2.5% glutaraldehyde in cacodylate buffer and 70% acetone. The duration of storage in buffer differed for each group, and SEM was used to examine the morphology. After the optimal processing protocol was made, we analysed the difference in the otoconial morphology in younger and older rats. RESULTS: The otoconia with shorter storage duration in phosphate buffer had more clear surface, while longer exposures resulted in coarse surface and fused otoconia. The otoconia stored in cacodylate buffer had smooth surface and showed grossly normal morphology regardless of exposure time. The otoconia fixed in acetone had irregular surface and was easily displaced. In older rats, the bodies of many otoconia were pitted, fissured, penetrated and eventually broken into several fragments. The size variation of utricular otoconia was greater in older rats. The giant otoconia were discovered frequently on the outer margin of utricular macula in older rats. The weakened or linked filaments that were cut in the older group were frequently observed. CONCLUSION: The appropriate processing for SEM is needed to observe the intact otoconial morphology. Older rats showed more degeneration of otoconia and linked filaments. This study for morphologic changes of senile otoconia is expected to be helpful in understanding the etiology of BPPV and aging effect.

Effect of Calvarial Cell Inoculated Onto the Biodegradable Barrier Membrane on the Bone Regeneration / 대한치주과학회지

Biodegradable barrier membrane has been demonstrated to have guided bone regeneration capacity on the animal study. The purpose of this study is to evaluate the effects of cultured calvarial cell inoculated on the biodegradable barrier membrane for the regeneration of the artificial bone defect. In this experiment 35 Sprague-Dawley male rats(mean BW 150gm) were used. 30 rats were divided into 3 groups. In group I, defects were covered periosteum without membrane. In group II, defects were repaired using biodegradable barrier membrane. In group III, the defects were repaired using biodegradable barrier membrane seeded with cultured calvarial cell. Every surgical procedure were performed under the general anesthesia by using with intravenous injection of Pentobarbital sodium(30mg/Kg). After anesthesia, 5 rats were sacrificed by decapitation to obtain the calvaria for bone cell culture. Calvarial cells were cultured with Dulbecco's Modified Essential Medium contained with 10% Fetal Bovine Serum under the conventional conditions. The number of cell inoculated on the membrane were 1x10(6) Cells/ml. The membrane were inserted on the artificial bone defect after 3 days of culture. A single 3-mm diameter full-thickness artificial calvarial defect was made in each animal by using with bone trephine drill. After the every surgical intervention of animal, all of the animals were sacrificed at 1, 2, 3 weeks after surgery by using of perfusion technique. For obtaining histological section, tissues were fixed in 2.5% Glutaraldehyde (0.1M cacodylate buffer, pH 7.2) and Karnovsky's fixative solution, and decalcified with 0.1M disodium ethylene diaminetetraacetate for 3 weeks. Tissue embeding was performed in paraffin and cut parallel to the surface of calvaria. Section in 7micrometer thickness of tissue was done and stained with Hematoxylin-Eosin. All the specimens were observed under the light microscopy. The following results were obtained. 1. During the whole period of experiment, fibrous connective tissue was revealed at 1week after surgery which meant rapid soft tissue recovery. The healing rate of defected area into new bone formation of the test group was observed more rapid tendency than other two groups. 2. The sequence of healing rate of bone defected area was as follows; test group, positive control, negative control group. 3. During the experiment, an osteoclastic cell around preexisted bone was not found. New bone formation

An experimental study on the microvascular anastomosis in applying the frozen arterial allograft in the rats

Although the autogenous vein graft is the most reliable in the fields of microvascular reconstruction, the microvascular allograft and microvascular prosthesis have been developed to be substitute for autogenous vein because it has many problems. In many experimental study have been reported highly variable patency rate and its thrombogenetic property of microvascular allograft. Especially, antigenicity of the homogenous vessels and immune reaction-induced thrombosis are main cause of homogenous microvascular anastomosis failure. For that reason, several investigators have attempted to reduce the antigenicity and improve the patency rate of microvascular allograft. The purpose of this study was to observe the healing process in applying frozen arterial allograft in the rats. In order to perform this study, 27 Sprague-Dawley rats, weighing 300gm or more selected. 12 carotid arterial anastomoses were performed in the rats by using microvascular end-to-end anastomosis as control group and 15 frozen(-196degreesC) arterial allografts were implanted into the carotid artery in the rats by using microvascular anastomosis as experimental group. The experimental rats were sacrificed on the 1st, 3rd, 7th, 14th, 28th, 56th day after operations. For scanning electron microscopic study, fixation was performed by perfusion of 2.5% glutaraldehyed-2% paraformaldehyed in 0.1M phosphate buffer at pH7.3. The specimens were post-fixated in 1% osmium tetraoxide for 2 hours, washed with cacodylate buffer, dehydrated in a series of ascending ethanol baths, critical point dried, coated with gold in a vacuum evaporator, and observed with a scanning electron microscope(JEOL, JSM-840-A, 20kV). For histologic examination taken specimens were embedded in paraffin, sectioned 6-8micrometer in thickness. The specimens were stained with hematoxylin-eosin stain method, examined under light microscope. The results were as follows; 1. The patency rate of control group was 92% and experimental group was 86%. 2. Endothelial cells regeneration at the anastomosis site of both group was partially appeared on the 1st week after experiment. 3. On the 2nd week after experiment, anastomosis site was completely covered with regenerated endothelial cell in both group, and the endothelial cell proliferated toward the graft at experimental group. 4. On the 4th, 8th week after experiment, the grafted artery was partially covered with endothelial cell at experimental group.

An electron microscopic study on the tissue changes in the pressure zones of rat molar periodontium incident to orthodontic tooth movement / 대한치과교정학회지

Incipient changes of the periodontal tissue in the pressure zones of rat molar subjected to the experimental force were studied by the transmission electron microscope. Experimental animals were consisted in 3 control and 21 experimental rats, of which one maxillary first molar was moved buccally with a fixed appliance which were exerting the force of 15 gm. After experimental period of 1 hour, 3 hours, 6 hours, 24 hours, 2 days, 3 days and 7 days, the animal were sacrificed with cardiac perfusion of 2.5% glutaraldehyde in the sodium cacodylate buffer and the experimental teeth with surrounding periodontal structures were processed for electron microscope. At the beginning of the tooth movement, periodontal ligaments of the pressure were compressed and collagenous fibers were arranged parallel to the root of the teeth and cell free zones in company with cell necrosis were followed. Cell free zones at the periodontal ligaments appreared in the 3 hour survival group, and getting severe with time lapse it became widespread in 2-3 day survival group and undermining bone resorption as a healing process was observed in 7 day survival group. Dilatation of mitochondria and swelling of the rER in the fibroblast and other connective tissue cells in the periodontal ligament were observed in the 3 hour survival group, which were characteristics of the incipient changes in the compressed periodontal ligament. Dilatation of nuclear membrane and pyknosis were followed by the destruction of the nucleus and cell membrane. There were no evidence in cell damage or necrosis of the alveolar bone adjacent to the hyalinized area of periodontal ligaments.