A Case Report of a Middle East Respiratory Syndrome Survivor with Kidney Biopsy Results

A 68-year old man diagnosed with Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) presented with multiple pneumonic infiltrations on his chest X-ray, and the patient was placed on a mechanical ventilator because of progressive respiratory failure. Urinary protein excretion steadily increased for a microalbumin to creatinine ratio of 538.4 mg/g Cr and a protein to creatinine ratio of 3,025.8 mg/g Cr. The isotope dilution mass spectrometry traceable serum creatinine level increased to 3.0 mg/dL. We performed a kidney biopsy 8 weeks after the onset of symptoms. Acute tubular necrosis was the main finding, and proteinaceous cast formation and acute tubulointerstitial nephritis were found. There were no electron dense deposits observed with electron microscopy. We could not verify the virus itself by in situ hybridization and confocal microscopy (MERS-CoV co-stained with dipeptidyl peptidase 4). The viremic status, urinary virus excretion, and timely kidney biopsy results should be investigated with thorough precautions to reveal the direct effects of MERS-CoV with respect to renal complications.     

Preparation of a bioartificial kidney using tubular epithelial cells, and an evaluation of Na+ active transport and morphological changes

We intend to develop a bioartificial kidney using tubular epithelial cells and artificial membranes, and to evaluate the reabsorptive function of the confluent layers. Madin-Darby canine kidney (MDCK) cells were cultured on a nucleopore polycarbonate membrane for up to 4 weeks after confluence to examine the influence of culture period on their properties, such as the localization of Na⁺/K⁺-ATPase and active Na⁺ transport. The results were as follows. Ouabain-sensitive Na⁺ active transport declined at 3 to 4 weeks after confluence in each matrix. The localization of Na⁺/K⁺-ATPase indicated depolarization in the cell membrane 3 to 4 weeks after confluence. Prolongation of the culture period increased the formation of an upheaving cell mass after the formation of the confluent monolayer. Scanning electron microscopy revealed fewer microvilli and more flat cells after 3 to 4 weeks of confluency. We conclude that the decline of Na⁺ active transport in the MDCK cells was due to both the formation of multilayers and a decline of cell function throughout the long period of culture following the formation of the confluent monolayers. Further study for selection of membrane material, the extracellular matrix, and species of cells should be continued. Laboratories for Structure and Function Research Department of Physiology     

Novel compound heterozygous GFPT1 mutations in a family with limb-girdle myasthenia with tubular aggregates

Limb-girdle myasthenia with tubular aggregates, a subtype of congenital myasthenic syndrome, is an extremely rare autosomal recessive genetic disease characterized by prominent limb-girdle weakness and good response to acetylcholinesterase inhibitor therapy. Herein, we reported two novel mutations of GFPT1 gene in a Chinese pedigree. Two siblings presented with fatigue, weakness of limb-girdle and decrement of the muscle action potential with repetitive nerve stimulation. Thus, myasthenia gravis was initially suspected, but anti-AChR antibodies were negative. Two novel missense mutations (p.Lys154Asn and p.Asn363Ser) in GFPT1 were identified through genetic testing conducted on 167 well-established genes associated with muscular diseases by targeted high throughput sequencing. Both mutations have not been recorded in the dsSNP database, Exome Aggregation Consortium database and 1000 Genomes Project database. The mutation sites were co-segregated with the phenotype and conserved between the different species. The mutations were not found in the 200 unrelated normal controls. Muscle biopsies revealed tubular aggregates, in accordance with previous reports with GFPT1 mutations. Subsequently, dramatic improvement in strength occurred following anti-cholinesterase therapy. Our study will be helpful for the diagnosis and treatment for Limb-girdle myasthenia with tubular aggregates.     

Histopathology of renal asphyxia in newborn piglets: Individual susceptibility to tubular changes

AIM: To analyze the effects on the kidney of hypoxiareoxygenation in an experimental model of normocapnic asphyxia.METHODS: To this end, 40 newborn Landrace/LargeWhite piglets aged 1-4 d were studied in this work. Hypoxia was induced by decreasing the inspired fiO_2 to 0.06-0.08. Animals were resuscitated with different fiO_2 and subdivided into 4 groups: group 1, 2, 3 and 4 received 18%, 21%, 40% and 100% O_2 respectively. Macroscopic examination was carried out to evidence possible pathological features. Tissue sample were obtained from both kidneys. Four or five micron paraffin sections were stained with H-E and PAS stain and examined under an optical microscope.RESULTS: Pathological changes, mainly affecting tubular cells, were observed in the vast majority of kidneys of asphyxiated piglets. The most frequent tubular changes were: tubular casts(95%), tubular dilatation(87.5%), tubular vacuolization(70%), tubular eosinophilia(52.5%), sloughing(50%), fragmentation of the brush border(50%), oedema(32.5%), apoptosis(15%) and glomerular changes(meningeal cell proliferation, capsular adhesion between the flocculus and Bowman's capsule, glomerulosclerosis and fibrous or cellular crescents associated with collapse of the glomerular tuft). Statistical analysis was carried out on changes observed when the animals were allocated in the 4 groups(χ~2-test 0.05). The statistical analysis showed no evidence of differences regarding kidney lesions among the animals groups.CONCLUSION: Our data show that renal pathology in newborn piglets is characterized by interindividual variability to hypoxia and is not associated with oxygen concentration.     

Tubular Carcinoma of the Breast: Clinicopathologic Features and Survival Outcome Compared with Ductal Carcinoma In Situ

Purpose

Tubular carcinoma (TC) of the breast is an uncommon histological subtype of invasive breast cancer with an excellent prognosis compared with standard invasive ductal carcinoma. Recent studies suggested a possible precursor role for low grade ductal carcinoma in situ (DCIS) in the development of TC. The goal of this analysis was to understand the clinicopathologic features and outcomes of TC by comparing TC with DCIS.

Methods

A retrospective review identified 70 patients with TC and 1,106 patients with DCIS between 1995 and 2011. Student t-test and Fisher exact test were used to compare the clinicopathologic characteristics of TC patients with those of DCIS patients. The Kaplan-Meier method and Cox regression analysis were used to determine disease-free survival (DFS) rates.

Results

Compared to DCIS, TC exhibited favorable clinicopathologic characteristics such as a lower nuclear grade (92.3%), higher expression of hormonal receptors (estrogen receptor-positive, 92.9%; progesterone receptor-positive, 87.0%), and less frequent overexpression of human epidermal growth receptor 2 (12.9%). DFS did not differ significantly between the TC and DCIS groups (5-year DFS, 100% vs. 96.7%; 10-year DFS, 92.3% vs. 93.3%; p=0.324), and cancer-specific deaths were not noted in either group. However, axillary lymph node involvement was observed in six (8.6%) of the 70 patients with TC. Three of these patients had small tumors (≤1 cm).

Conclusion

In our study cohort, TC was associated with an excellent prognosis and a low rate of lymph node metastasis. However, lymph nodes metastases were found even in patients with small tumors (≤1 cm). Axillary staging must be considered for all patients with TC of the breast.     

Minimally invasive scoliosis surgery for adolescent idiopathic scoliosis using posterior mini-open technique

The purpose of this study aimed to analyze and evaluate the radiologic and clinical outcomes of minimally invasive scoliosis surgery (MISS) for correcting adolescent idiopathic scoliosis (AIS) using the mini-open technique. Thirty-four AIS patients who underwent MISS using the mini-open technique for deformity correction. Using two to four 3-centimeter-long skin incisions (mini-open) and tubular retractors, we performed screw fixations, rod assembly, rod derotation maneuver (RD), and bone graft. For thoracoplasty, four to six ribs were resected using the same incisions. Correction was attempted using rod translation and RD maneuvers. Radiological outcomes and clinical outcomes (SRS-22) were evaluated. Mean preoperative Cobb’s angle was 61.3° and curve flexibility (major curve) was 26.1%. This angle was corrected to 21.6° with a correction rate of 65.2% (P < 0.001). The coronal balance was not changed significantly. Sagittal vertical axes were corrected from −3.5 mm to 8.6 mm (–22 to 36.3 mm) (P = 0.009). Thoracic kyphosis angles and lumbar lordosis angles were not changed significantly but the values were within normal range. Each score of self-image in the SRS-22 questionnaire as well as the total score were improved significantly (P < 0.001). In conclusion, the MISS for correcting AIS using the mini-open technique showed comparable radiologic and clinical outcomes with fewer complications in patients with non-rigid scoliosis with Cobb’s angle between 50° and 80°. Long-term results of this novel MISS using the mini-open technique could further strengthen the rationale for adopting this technique for curve correction in selected cases of AIS.     

Elevated accumulation of hyaluronate in the tubular bones of osteogenesis imperfecta

The content and composition of glycosaminoglycans in the tubular bones of osteogenesis imperfecta were compared to those in the tubular bones of age-matched controls. Chondroitin sulfate was the major glycosaminoglycan (70–80% of total) both in the normal and pathological bones, and its level, based on the tissue wet weight, was slightly less in the pathological bones. The composition of chondroitin sulfate disaccharide units in the pathological samples was different from those of the control; a lower proportion of chondroitin 4-sulfate unit. Hyaluronate accounted for at most 7% of total glycosaminoglycans from the normal bones. The hyaluronate content of the pathological bones was 1.5- to 3-fold higher than that of the controls. Glycosaminoglycans have been shown to participate in the formation of a functional supramolecular complex in extracellular matrices. Therefore, it may be postulated that the abnormalities in glycosaminoglycan composition in the tubular bones of osteogenesis imperfecta is implicated in some clinical aspects of this connective tissue disorder such as the bony fragility.     

The relationship between renal metabolism and proximal tubule transport during ontogeny

The proximal tubules of newborn and adult animals reabsorb a similar fraction of the filtered load of Na⁺ and H₂O (65%–70%). In tubules from adult animals, transcellular, active Na⁺ reabsorption accounts for one-third of the total, while two-thirds occur passively through the paracellular pathway, driven by hydrostatic and oncotic forces (one-third) and by cell-generated effective osmotic and ionic gradients (one-third). Since two-thirds of the Na⁺ is reabsorbed passively and does not require energy, the mature proximal tubule has a high Na⁺/O₂ molar ratio (48 Eq of Na⁺/mol of O₂). Measurements of ouabain-sensitive oxygen consumption in suspensions of proximal tubules indicate that in newborn, aerobic metabolism can support about 50% of the net Na⁺ transport rate compared with the 33% in tubules from adult animals. Independent confirmation of the direct and proportional relationship between active Na⁺ transport and ouabain-sensitive O₂ consumption exists for the adult but not for the newborn. However, measurements of epithelial conductances and of transepithelial hydrostatic and oncotic pressure differences indicate that passive paracellular fluxes can account for the remaining 50% of the proximal Na⁺ reabsorption in newborn. The high permeability of the proximal tubules of newborn animals to small molecular weight solutes suggests that cell-generated osmotic and ionic transepithelial gradients are minimal in the tubules of newborn animals. Yet in the newborn, the osmolality of the end proximal tubule fluid was found to exceed that in plasma. This indicates that osmotic gradients due to differences in reflection coefficients for preferentially reabsorbed solutes and Cl^– do exist across the proximal tubules of the newborn and suggests that these gradients may contribute to Na⁺ and H₂O reabsorption. If this is indeed the case, then the contribution of active and of hydrostatic and oncotic pressure-driven flows to the overall reabsorption of Na⁺ and fluid has been overestimated. Resolution of this discrepancy requires measurements of the reflection coefficients for HCO ₃ ^– and Cl^– in the proximal tubule of the newborn. The metabolic processes by which energy is supplied to renal proximal cells during development are also incompletely characterized. There is evidence that maturation of aerobic metabolism, Krebs cycle enzymes activity, and of the mitochondrial membrane surface area precede the development of net reabsorptive transport (Na⁺, H₂O, HCO₃, glucose). By contrast, maturation of Na⁺–K⁺-ATPase activity at the basolateral cell membrane follows that in reabsorptive transport and does not limit its development. The extent to which age-related changes in reabsorptive fluxes are due to the development of luminal membrane transport systems, to the decrease in paracellular permeability, or both remains to be determined. The high activity of enzymes in the hexosemonophosphate pathway and the high NADH/NAD ratio present during the first few weeks of extrauterine life poise the proximal tubules for high rates of biosynthesis of membrane lipids, glycoproteins, nucleic acids, and transporter proteins necessary for final differentiation.     

Lack of effects of oxolinic acid on spermatogenesis in young adult and aged Wistar rats

Prolonged treatment with oxolinic acid is known to elevate serum luteinizing hormone (LH) levels, resulting in induction of Leydig cell tumors in rats. In a carcinogenicity study of the compound, tubular atrophy of the testis was also increased, suggesting that oxolinic acid might affect spermatogenesis. The present study was therefore performed using rats of different ages with a particular focus on seminiferous tubule alteration and its relation to Leydig cell proliferation. Young adult (7 weeks of age) and aged (52 weeks of age) males of the Wistar strain were administered oxolinic acid at dietary concentrations of 0 (basal diet), 300, 1000 or 3000 ppm for 4 (all groups), 13 (0 and 3000 ppm groups), 26 (0 and 3000 ppm groups), or 52 weeks (0 and 3000 ppm groups of aged rats). Serum LH levels were elevated in both young adult and aged animals treated with 3000 ppm at most examined time points. While testosterone levels were also increased at the early time points in young adult, this was not the case in older animals. Elevation of the incidences of foci and/or focal hyperplasia of Leydig cells was noted but was only slight limited to aged rats treated with 3000 ppm after 26 weeks. Furthermore, it did not appear to be related to seminiferous tubular alteration. No treatment-related histopathological abnormalities could be detected in any treatment group, and morphometrical stage analysis of spermatogenesis conducted for the control and 3000 ppm-treated groups demonstrated no lesions. These results provide strong evidence that prolonged oxolinic treatment does not directly induce testicular toxicity or altered spermatogenesis in either young adult or aged rats, except for slight increase of Leydig cell proliferative lesions caused by elevated serum LH levels. Aged rats might have higher sensitivity than young adults to the effects of oxolinic acid on proliferative lesions of Leydig cells.     

Membranous nephropathy,interstitial nephritis,and fanconi syndrome — glomerular antigen

We characterized the glomerular antigen of membranous nephropathy (MN) in a child with the trial of MN, proximal renal tubular basement membrane autoantibody (TBMAb)-associated interstitial nephritis (ITN), and Fanconi syndrome. Granular staining was demonstrated for human gp600 in the vicinity of immune deposits of MN along glomerular capillary loops, using a monospecific polyclonal antibody to human gp600 by indirect immunofluorescence. However, no staining was observed in the MN deposits for receptor-associated protein. Membranous nephropathy preceded the development of TBMAbs, ITN, and Fanconi syndrome by 1 year, showing that the MN lesion does not result from the initial immunological injury to the tubulointerstitium, as postulated earlier. We confirmed the reactivity of TBMAbs with the recently deseribed rabbit 58-kilodalton (kDa) tubular basement membrane antigen (TBMAg). However, this is the first report to show reactivity of these antibodies with the human 58-kDa protein. Also, we found that TBMAg is comprised of a single protein band of 58 kDa, unlike the previously described combination of two protein bands (58 kDa and 175 kDa). In this patient, following prednisone treatment, the TBMAbs became undetectable, and the nephrotic syndrome and Fanconi syndrome resolved, thus suggesting a causal role of TBMAbs in the pathogenesis of Fanconi syndrome. We postulate that in this rare disorder, renal lesions result from an autoimmune response to the 58-kDa TBMAg and possibly to gp600, and that the predisposition to autoimmunity is genetically linked to the HLA B7 serotype.