In Vitro and In Vivo Replication for Scanning Electron Microscopy of the Cervical Region of Human Teeth

A replica technique for scanning electron microscopy (SEM) of the cervical region of human teeth was evaluated on extracted premolar teeth by comparing the replicas and the original specimens in the SEM. For in vivo application, the technique was modified to circumvent contamination by saliva and gingival exudate. Impressions were taken with an addition silicone polyvinylsiloxane material and the replicas were poured in epoxy resin die material. A surface active dentine conditioner facilitated flow of the impression material into irregular surface areas; in vivo a scavenger impression was used to remove surface debris. Custom trays were made of light-cured acrylic resin for the in vivo impressions. The method faithfully reproduced surface detail in the amelocemental region. In vivo the scavenger impression followed by application of the surface-active conditioner effectively cleaned the tooth surface. The custom tray allowed selection and inclusion of landmarks and ensured reproducibility. The method meets the requirements of a simple, reproducible, non-invasive means of documenting the micromorphology of the cervical region of the teeth

Discontinuities in the endothelium of epiphyseal cartilage canals and relevance to joint disease in foals

Cartilage canals have been shown to contain discontinuous blood vessels that enable circulating bacteria to bind to cartilage matrix, leading to vascular occlusion and associated pathological changes in pigs and chickens. It is also inconsistently reported that cartilage canals are surrounded by a cellular or acellular wall that may influence whether bacterial binding can occur. It is not known whether equine cartilage canals contain discontinuous endothelium or are surrounded by a wall. This study aimed to examine whether there were discontinuities in the endothelium of cartilage canal vessels, and whether canals had a cellular or acellular wall, in the epiphyseal growth cartilage of foals. Epiphyseal growth cartilage from the proximal third of the medial trochlear ridge of the distal femur from six healthy foals that were 1, 24, 35, 47, 118 and 122 days old and of different breeds and sexes was examined by light microscopy (LM), transmission electron microscopy (TEM) and immunohistochemistry. The majority of patent cartilage canals contained blood vessels that were lined by a thin layer of continuous endothelium. Fenestrations were found in two locations in one venule in a patent cartilage canal located deep in the growth cartilage and close to the ossification front in the 118-day-old foal. Chondrifying cartilage canals in all TEM-examined foals contained degenerated endothelial cells that were detached from the basement membrane, resulting in gap formation. Thirty-three percent of all canals were surrounded by a hypercellular rim that was interpreted as contribution of chondrocytes to growth cartilage. On LM, 69% of all cartilage canals were surrounded by a ring of matrix that stained intensely eosinophilic and consisted of collagen fibres on TEM that were confirmed to be collagen type I by immunohistochemistry. In summary, two types of discontinuity were observed in the endothelium of equine epiphyseal cartilage canal vessels: fenestrations were observed in a patent cartilage canal in the 118-day-old foal; and gaps were observed in chondrifying cartilage canals in all TEM-examined foals. Canals were not surrounded by any cellular wall, but a large proportion was surrounded by an acellular wall consisting of collagen type I. Bacterial binding can therefore probably occur in horses by mechanisms that are similar to those previously demonstrated in pigs and chickens

Alternative Exon Usage Selectively Determines Both Tissue Distribution and Subcellular Localization of the acyl-CoA Thioesterase 7 Gene Products.

Acyl-CoA thioesterases (ACOTs) catalyze the hydrolysis of acyl-CoAs to free fatty acids and coenzyme A. Recent studies have demonstrated that one gene named Acot7, reported to be mainly expressed in brain and testis, is transcribed in several different isoforms by alternative usage of first exons. Strongly decreased levels of ACOT7 activity and protein in both mitochondria and cytosol was reported in patients diagnosed with fatty acid oxidation defects, linking ACOT7 function to regulation of fatty acid oxidation in other tissues. In this study, we have identified five possible first exons in mouse Acot7 (Acot7a-e) and show that all five first exons are transcribed in a tissue specific manner. Taken together, these data show that the Acot7 gene is expressed as multiple isoforms in a tissue specific manner, and that expression in tissues other than brain and testis is likely to play important roles in fatty acid metabolism

Evidence for a morphologically distinct and functionally robust cell type in the proximal tubules of human kidney.

Acute tubular necrosis (ATN), elicited by ischemia and/or toxicity, is a potentially life-threatening condition. Histologically, ATN corresponds to necrosis and detachment of renal tubular epithelial cells. However, the tubules possess a considerable regenerative capacity and may be restored. We have previously identified a scattered population of progenitor-like cells within the proximal tubules, sharing marker expression with the parietal epithelial cells of Bowman's capsule as well as with renal tubules regenerating after ATN. In the present analysis, we use transmission electron microscopy, immunoelectron microscopy and immunofluorescence of human kidney cortex to further explore these cells. We demonstrate that the cells are smaller and have drastically fewer mitochondria than the surrounding proximal tubule cells. They also display strong expression of several structural proteins such as vimentin, collagen-7A1 and the tight junction protein claudin-1. To functionally assess these cells, we also developed a novel human kidney explant model of ATN demonstrating that the cells are more resilient to injury than the surrounding proximal tubular cells. Taken together the results suggest a novel robust cell type with a contrasting biological role to that of the bulk of proximal tubular epithelium

Thymidine Kinase 2 Deficiency-Induced mtDNA Depletion in Mouse Liver Leads to Defect beta-Oxidation

Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/-)) that progressively loses its mtDNA. The TK2(-/-) mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/-) mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/-) mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/-) mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial beta-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/-) mice causes impaired mitochondrial function that leads to defect beta-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies

The Zebrafish Orthologue of the Dyslexia Candidate Gene DYX1C1 Is Essential for Cilia Growth and Function

Peer reviewe

Renal Morphology, Clinical Findings, and Progression Rate in Mesoamerican Nephropathy.

BACKGROUND: Mesoamerican nephropathy (MeN) is a chronic kidney disease affecting rural inhabitants in Central America. We have previously described the renal morphology in 8 patients from El Salvador. To confirm the renal pathology, we have studied kidney biopsies from patients with MeN in Nicaragua. Follow-up urine and blood samples from both biopsy studies were collected to investigate the natural history. STUDY DESIGN: Case series. SETTINGS & PARTICIPANTS: In the kidney biopsy study, 19 male sugarcane workers in Nicaragua with suspected MeN were investigated with questionnaires, kidney biopsies, and blood and urine analysis. Inclusion criteria were age 20 to 65 years and plasma creatinine level of 1.13 to 2.49mg/dL or estimated glomerular filtration rate (eGFR) of 30 to 80mL/min/1.73m2. Exclusion criteria were proteinuria with protein excretion > 3g/24 h, uncontrolled hypertension, diabetes mellitus, or other known kidney disease. In the follow up-study, blood and urine from the kidney biopsy study in Nicaragua (n=18) and our previous biopsy study of MeN cases in El Salvador (n=7) were collected 1 to 1.5 and 2 to 2.5 years after biopsy, respectively. OUTCOMES: Renal morphology, clinical, and biochemical characteristics, change in eGFR per year. MEASUREMENTS: eGFR was calculated using the CKD-EPI creatinine (eGFRcr), cystatin C (eGFRcys), and creatinine-cystatin C (eGFRcr-cys) equations. RESULTS: In the kidney biopsy study, participants had a mean eGFRcr of 57 (range, 33-96) mL/min/1.73m2. 47% had low plasma sodium and 21% had low plasma potassium levels. 16 kidney biopsies were representative and showed glomerulosclerosis (mean, 38%), glomerular hypertrophy, and signs of chronic glomerular ischemia. Mild to moderate tubulointerstitial damage and mostly mild vascular changes were seen. In the follow up-study, median duration of follow-up was 13 (range, 13-27) months. Mean change in eGFRcr was -4.4±8.4 (range, -27.7 to 10.2) mL/min/1.73m2 per year. Most patients had stopped working with sugarcane cultivation. LIMITATIONS: 3 biopsy specimens had 4 or fewer glomeruli. CONCLUSIONS: This study confirms the renal morphology of MeN: chronic glomerular and tubulointerstitial damage with glomerulosclerosis and chronic glomerular ischemia. Follow-up data show that eGFRs, on average, deteriorated

Маркеры воспаления при атеросклеротических изменениях сосудистой стенки у пациентов с ишемической болезнью сердца

ишемическая болезнь сердцаатеросклерозцитокин

CRIM1 is localized to the podocyte filtration slit diaphragm of the adult human kidney

Background. CRIM1 is a plasma membrane bound protein containing six cysteine-rich repeats (CRR). Through these, CRIM1 has been shown to interact with a subgroup of the TGF-β superfamily, the bone morphogenic proteins (BMP) isoforms 2, 4 and 7. The probable action is to modulate the signalling properties of these factors. CRIM1 has also been shown to regulate the release of VEGFA by podocytes during renal organogenesis. Knock-out studies in mice have shown that CRIM1 is critically involved in the development of the central nervous system, eye and kidney. Replacement of CRIM1 with a defective version leads to renal dysgenesis and perinatal death. We have analysed the distribution of CRIM1 in adult human renal tissue