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Weiming Yu

Publications and source records attributed to Weiming Yu.

11 recordsLinked to original sources
PubMed2006

Fabry disease and nephrogenic diabetes insipidus.

Fabry disease is a lysosomal storage disorder with kidney involvement. The initial manifestation of kidney disease is often impaired urinary concentrating ability in adolescence or young adulthood. We describe a boy diagnosed prenatally with Fabry disease who presented with polyuria, polydipsia, hypertension, hypokalaemia and proteinuria at 7 years of age. A formal water-deprivation test followed by vasopressin challenge confirmed nephrogenic diabetes insipidus. A renal biopsy revealed findings typical of Fabry disease. Angiotensin converting-enzyme therapy resulted in rapid improvement of symptoms, normalization of blood pressure and resolution of hypokalaemia and proteinuria. This child is the youngest reported Fabry disease patient with documented renal pathology and clinical manifestations of hypertension, proteinuria and nephrogenic diabetes insipidus.

Child↗
PubMed2006

Quantitative microscopic approaches for studying kidney functions.

Intravital ratiometric microscopy is a powerful method for quantitative study of kidney functions. As demonstrated in the examples, both the generalized polarity and direct ratio imaging approaches allow investigators to address basic and important questions such as those related to filtration, permeability and reabsorption. Both approaches have similar advantageous for in vivo imaging. However, they have different sensitivities and responses to the component intensity changes. Therefore, investigators must design their experiments based on the characteristics of the generalized polarity function and direct ratio approach.

Absorption↗
PubMed2005

Rapid destruction of encapsulated islet xenografts by NOD mice is CD4-dependent and facilitated by B-cells: innate immunity and autoimmunity do not play significant roles.

BACKGROUND: Spontaneously diabetic NOD mice rapidly reject microencapsulated islet xenografts via an intense pericapsular inflammatory response. METHODS: Tilapia (fish) islets were encapsulated in 1.5% alginate gel microspheres. Recipients in series 1 were spontaneously diabetic NOD mice and streptozotocin-diabetic nude, euthymic Balb/c, prediabetic NOD, and NOR (a recombinant congenic strain not prone to autoimmune diabetes) mice. Recipients in Series 2 were STZ-diabetic NOD, NOD-scid, NOD CD4 T-cell KO, NOD CD8 T-cell KO, and NOD B-cell KO mice. RESULTS: In Series 1, encapsulated fish islet grafts uniformly survived long-term in nude mice but were rejected in Balb/c and, at a markedly accelerated rate, in spontaneously diabetic NOD, streptozotocin-diabetic NOD and NOR recipients. Histologically, intense inflammation (macrophages and eosinophils) surrounding the microcapsules was seen only in NOD and NOR recipients. In Series 2, encapsulated fish islets uniformly survived long-term in NOD-scid and NOD CD4 KO mice; graft survival was markedly prolonged in B-cell KO (P<0.001) but not CD8 KO mice. CONCLUSIONS: The rapid rejection of alginate encapsulated islet xenografts by NOD mice is not solely a consequence of beta-cell directed autoimmunity nor is it merely a vigorous innate immune response. Graft rejection requires CD4 T-cells, is facilitated by B-cells, and does not require CD8 T-cells.

Animals↗
PubMed2005

Quantitative intravital microscopy using a Generalized Polarity concept for kidney studies.

In this article, we describe a ratiometric intravital two-photon microscopy technique for studying glomerular permeability and differences in proximal tubule cell reabsorption. This quantitative approach is based on the Generalized Polarity (GP) concept, in which the intensity difference between two fluorescent molecules is normalized to the total intensity produced by the two dyes. After an initial intravenous injection of a mixture of 3-, 40-, and 70-kDa fluorescently labeled dextrans into live Munich-Wistar-Frömter (MWF) rats, we were able to monitor changes in the GP values between any two dyes within local regions of the kidney, including the glomerulus, Bowman's capsule, proximal tubule lumens and proximal tubule cells, and individual capillary vessels. We were able to quantify accumulations of different dextrans in the Bowman's space and in tubular lumens as well as reabsorption by proximal tubular cells at different time points in the same rat. We found that for 6- to 8-wk-old MWF rats that developed spontaneous albuminuria, the 40- and 70-kDa dextrans, with hydrodynamic radii larger than albumin, were differentially filtered, but both were able to pass the glomerular filtration barrier and enter into the urinary space of the Bowman's capsule within a few seconds after intravenous infusion. Using GP image analysis, we found that negatively charged dextrans of both 40 and 70 kDa were better reabsorbed by the proximal tubule cells than the neutrally charged 40-kDa dextran. These results demonstrate the potential power of the GP imaging technique for quantitative studies of glomerular filtration and tubular reabsorption.

Albuminuria↗
PubMed2005

Lack of response of a metastatic renal perivascular epithelial cell tumor (PEComa) to successive courses of DTIC based-therapy and imatinib mesylate.

An 11 year-old girl presented with two large abdominal masses in the left flank and epigastrium and left supraclavicular lymphadenopathy. Subsequent investigations led to the diagnosis of metastatic perivascular epithelioid cell tumor (PEComa) arising from the left kidney. Effective treatment for this rare tumor is not yet known. The tumor did not respond to an initial treatment of two cycles of a dacarbazine (DTIC) based regimen. She was placed on a trial of imatinib mesylate based on tumor expression of c-KIT, a tyrosine kinase targeted by this drug. This report highlights the first documented case of the use of imatinib for PEComa. Lack of response and adverse effects of the drug required discontinuation of therapy.

Angiomyolipoma↗
PubMed2005

C-Kit-positive metastatic malignant pigmented clear-cell epithelioid tumor arising from the kidney in a child without tuberous sclerosis.

We report the first pediatric case of malignant pigmented epithelioid clear-cell tumor arising from kidney; the lesion occurred in a 12-year-old girl without tuberous sclerosis. The tumor was widely metastatic to the retroperitoneum and chest, and the patient died of the disease 9 months after diagnosis, despite active chemotherapy. Pigmented epithelioid clear-cell tumor of the kidney is a rare variant of epithelioid angiomyolipoma and a member of the family of perivascular epithelioid cell tumors (PEComas). The tumor demonstrated overlapping features between clear-cell sugar tumor and epithelioid variant of angiomyolipoma. Tumor cells were positive for HMB-45 expression, negative for any evidence of muscular differentiation, and contained melanin pigment and premelanosomes in the cytoplasm. Diffuse C-Kit (CD117) positivity was identified throughout the tumor. This is the first report of C-Kit-positive malignant PEComas.

Angiomyolipoma↗
PubMed2003

Undifferentiated mesenchymal neoplasm of the esophagus in a child: case report and comparison with gastrointestinal stromal tumor.

Mesenchymal neoplasms of the esophagus are relatively uncommon in adults and exceedingly rare in children. Childhood tumors consist almost exclusively of smooth muscle tumors (leiomyomas). We report a case of an undifferentiated mesenchymal neoplasm occurring in the distal esophagus of a 15-year-old boy which is not a gastrointestinal stromal tumor. To our knowledge, this is the first reported case of such a neoplasm occurring in the esophagus of either an adult or child.

Adolescent↗
PubMed2003

Novel light microscopy imaging techniques in nephrology.

PURPOSE OF REVIEW: As more genomes are sequenced, the difficult task of characterizing the gene products of these genomes becomes the compelling mission of biological sciences. The melding of whole organ physiology with transgenic animal models, gene transfer methods and RNA silencing promises to form the next wave of scientific inquiry. A host of new microscopy imaging technologies enables researchers to directly visualize gene products, probe alterations in cell function in transgenic animals and map tissue organization. This review will describe these microscopy imaging techniques, their advantages, imaging properties and limitations. RECENT FINDINGS: New optical methods such as two-photon confocal microscopy, fluorescence resonance energy transfer, and total internal fluorescence reflectance microscopy are increasingly being applied to extend our understanding of whole organ and renal epithelial function. Two-photon confocal microscopy has been used to image directly into the kidney of living animals. Fluorescence resonance energy transfer has been used to directly visualize transcription factor complexes within the nucleus while total internal fluorescence reflectance microscopy has permitted direct observation of protein delivery to the plasma membrane. SUMMARY: The application of these optical techniques along with the ability to label virtually any protein with a fluorescent tag will enable researchers to study cellular processes and whole organ function in vivo. Light microscopy methods will allow an advance from semi-quantitative to quantitative approaches to problems of relevance to physiologists studying issues related to renal function.

Animals↗
PubMed2002

T-cell/periodic acid-Schiff stain: a useful tool in the evaluation of tubulointerstitial infiltrates as a component of renal allograft rejection.

Distinguishing between tubulitis and tubulointerstitial mononuclear cell infiltrates and determining the severity of tubulitis are critical components of diagnosing and grading renal allograft rejection using the 1993 Banff schema, the revised 1997 Banff schema, or the Cooperative Clinical Trials in Transplantation grading system. We describe a novel staining method, the T-PAS stain (CD3 and periodic acid-Schiff), which removes some of the subjectivity in the evaluation of tubulointerstitial infiltrates in renal allograft biopsies. The method simply combines two routine stains, immunoperoxidase staining for T cells (CD3) and periodic acid-Schiff (PAS) staining for tubular basement membrane, on the same section.

Basement Membrane↗
PubMedDate not supplied

A rare case of interstitial del(1)(p34.3p36.11) diagnosed prenatally.

We report a very rare constitutional interstitial deletion of chromosome 1p defined within 1p34.3-36.11 bands with an intact pter. The diagnosis was made by standard cytogenetics and fluorescence in situ hybridization (FISH) studies on a cordocentesis specimen obtained at 21 weeks gestation. Termination of pregnancy was performed at 22 weeks gestation due to the ultrasound diagnosis of congenital heart disease. Autopsy confirmed congenital heart disease (cardiomegaly, Ebstein's anomaly, secundum atrial septal defect, subendocardial fibroelastosis), pulmonary lymphangiectasis, a high arched palate, short neck, and bilateral long proximally implanted thumbs. To our knowledge, this is the first case of del(1) (p34.3p36.11) diagnosed prenatally.

Abnormalities, Multiple↗