We studied the nonenzymatic glycosylation of lens epithelial basement membranes (LEBM) of senile cataractous lenses of both diabetic and nondiabetic patients. The human LEBMs were isolated from surgically removed senile cataracts and purified by osmotic lysis and detergent treatments. Glycosylation assay of LEBMs was done using the colorimetric method of Fluckiger and Winterhalter. The glycosylation value ranged from 16.39 to 92.56 n mol/mg protein overall, with a mean of 63.54 +/- 24.56 n mol/mg protein for the diabetic specimens and a mean of 29.97 +/- 14.48 n mol/mg protein for the nondiabetic controls (P = 0.009). The study confirms our previous observation of in vivo glycosylation of the LEBM and further establishes that diabetic patients have a twofold increase in the amount of LEBM glycosylation when compared to their nondiabetic counterparts.
Aged ; Basement Membrane/metabolism ; Cataract/metabolism ; Diabetes Mellitus, Type 2/*metabolism ; Epithelium/metabolism ; Female ; Glucose/metabolism ; Glycosylation ; Humans ; Lens, Crystalline/*metabolism ; Male

We studied the nonenzymatic glycosylation of lens epithelial basement membranes (LEBM) of senile cataractous lenses of both diabetic and nondiabetic patients. The human LEBMs were isolated from surgically removed senile cataracts and purified by osmotic lysis and detergent treatments. Glycosylation assay of LEBMs was done using the colorimetric method of Fluckiger and Winterhalter. The glycosylation value ranged from 16.39 to 92.56 n mol/mg protein overall, with a mean of 63.54 +/- 24.56 n mol/mg protein for the diabetic specimens and a mean of 29.97 +/- 14.48 n mol/mg protein for the nondiabetic controls (P = 0.009). The study confirms our previous observation of in vivo glycosylation of the LEBM and further establishes that diabetic patients have a twofold increase in the amount of LEBM glycosylation when compared to their nondiabetic counterparts.
Aged ; Basement Membrane/metabolism ; Cataract/metabolism ; Diabetes Mellitus, Type 2/*metabolism ; Epithelium/metabolism ; Female ; Glucose/metabolism ; Glycosylation ; Humans ; Lens, Crystalline/*metabolism ; Male

OBJECTIVES: The thickening of the glomerular basement membrane in rats after Vacor ingestion was examined by electron microscopy. This study was performed to elucidate which biochemical components changed in the glomerular basement membrane after Vacor-induced diabetic glomerulopathy. METHODS: Immunohistochemical analyses of type IV collagen, laminin, fibronectin and chondroitin sulfate proteoglycan were performed. A single dose of Vacor (molecular weight 272), 80 mg/kg, was administered to adult male Wistar rats by orogastric canule, and the animals were sacrificed at 0.5, 1, 3, 7, 14, 28 and 56 days after administration. RESULTS: Mild thickening of the glomerular basement membrane was evident 7 days after Vacor administration, and the width of the glomerular basement membrane was more than twice that of normal controls at 28 and 56 days. Significantly increased expressions of type IV collagen, laminin, fibronectin and neutral polysaccharide in the thickened glomerular basement membrane were noted 14 to 56 days after administration, and a mildly increased expression of chondroitin sulfate proteoglycan appeared between 3 to 7 days. CONCLUSION: These abnormally increased glomerular basement membrane components might be part of what causes diabetic nephropathy after Vacor administration.
Animal ; Basement Membrane/pathology ; Basement Membrane/metabolism ; Basement Membrane/drug effects ; Diabetic Nephropathies/pathology ; Diabetic Nephropathies/metabolism ; Diabetic Nephropathies/chemically induced* ; Extracellular Matrix Proteins/metabolism ; Kidney Glomerulus/pathology ; Kidney Glomerulus/metabolism ; Kidney Glomerulus/drug effects ; Male ; Phenylurea Compounds/toxicity* ; Proteochondroitin Sulfates/metabolism ; Rats ; Rats, Wistar

OBJECTIVETo investigate the clinicopathological manifestations of early renal amyloidosis (AL) and its diagnostic criteria.

METHODSFifteen cases with early renal amyloidosis admitted from 1994 to 2001 were collected from the hospital, and their clinical and pathological features were reviewed. Of them, the initial diagnoses were not made by depending findings from the light microscopy (LM) and immunofluorescense (IF), but confirmed by electron microscopy (EM) afterwards. Immuno-electron microscopy (IEM) were applied for amyloidosis typing.

RESULTSMost patients of early renal AL were in the middle to old age. Nephrotic syndrome was the most prominent symptoms and signs accompanying with rare microscopic hematuria and hypertension. Most of them had a normal renal function. Pathological examinations of renal biopsies using LM and IF showed mild mesangial proliferation and mild thickening of glomerular basement membrane (GBM). Immunoglobulins and complements were negative or only scanty in certain cases, but in all cases there was a light chain protein deposition homogeously. There were 4 cases of minimal change glomerulopathy, 5 cases of mild mesangial proliferative glomerulonephritis, 5 cases of stage I membranous nephropathy, and 1 case of cast nephropathy diagnosed with LM. The amyloid fibrils (diameter 8 - 10 nm) were randomly distributed in the mesangium, along GBM and at the arteriolar wall under EM. Additionally, Congo red staining was positive. IEM demonstrated that amyloid fibrils labeled with colloid gold was combined with a kind of light chain protein which was confirmed as the light chain type of AL.

CONCLUSIONSThe diagnosis of early renal AL was occasionally neglected by depending only findings of LM and LF. However, special amyloid fibrils can be detected using EM. EM observation is an indispensable technique for the diagnosis of early renal AL and the typing of AL may further be determined by using IEM.

Adult ; Aged ; Amyloidosis ; metabolism ; pathology ; Basement Membrane ; metabolism ; Female ; Humans ; Immunoglobulin Light Chains ; metabolism ; Kidney Diseases ; metabolism ; pathology ; Kidney Glomerulus ; metabolism ; pathology ; Male ; Microscopy, Immunoelectron ; Middle Aged

Biopsy ; Female ; Glomerular Basement Membrane ; metabolism ; Hashimoto Disease ; metabolism ; pathology ; Humans ; Kidney Diseases ; metabolism ; pathology ; Middle Aged ; Proteinuria ; metabolism ; pathology ; Sjogren's Syndrome ; metabolism ; pathology

The pathogenesis of the exfoliation syndrome is still unknown. To clarify the etiology of the exfoliation syndrome, we examined the iris taken from a patient with exfoliative glaucoma during cataract surgery using light microscope, polarization microscopy and electron microscopy. The amorphous substance around the iris pigment epithelium and stroma were stained purplish red in PAS staining and showed purplish red metachromasia in toluidine blue staining. In electromicroscopic examination, we observed that many fibrillar materials were deposited at basement membrane and partially detached basement membrane around the pigment epithelium of the iris. Therefore we concluded that the exfoliative materials in this syndrome is a sort of glycoprotein and originated from the abnormal synthesis and metabolism of the basement membrane in the eye.
Basement Membrane ; Cataract ; Epithelium ; Exfoliation Syndrome* ; Glaucoma ; Glycoproteins ; Humans ; Iris* ; Metabolism ; Microscopy, Electron ; Microscopy, Polarization ; Tolonium Chloride

OBJECTIVETo observe the thick basement membrane-like layer under the damaged epithelium in patients with chronic rhinosinusitis (CRS) and to study its principal components.

METHODSPatients (n = 40) with CRS undergoing functional endoscopic sinus surgery were recruited for the study. Patients (n = 10) with no evidence of sinus disease were used as control subjects. Ethmoidal sinus mucosa specimen were stained by PAS staining to measure the thickness of basement membrane-like layer. Immunohistochemical staining, picrosirius-polarization method and transmission electron microscopy (TEM) were used to analyse the nature of the layer.

RESULTSThe thickness of basement membrane-like layer in CRS type I and CRS type II were significantly increased compared with normal control subjects (t = 5. 426, P < 0. 01; t = 8. 375, P < 0.01). The thickness of CRS type II was significantly greater compared with CRS type I (t = 3. 908, P < 0.01). There was no difference between atopic group and inotropic group (t = 0.803, P> 0.05). There was no expression of fibronectin, laminin, IgA, IgG and IgM in the thick basement membrane-like layer. A thick reticular structure containing collagen fibrils and devoid of cellular elements was observed by TEM.

CONCLUSIONSThis study demonstrates that a long-standing chronic inflammation leads to deposition of collagens type I , III and IV under the damaged epithelium, resulting in an increasingly thick sub-basement membrane layer.

Adolescent ; Adult ; Aged ; Basement Membrane ; metabolism ; pathology ; Case-Control Studies ; Chronic Disease ; Collagen ; metabolism ; Female ; Humans ; Male ; Middle Aged ; Nasal Mucosa ; metabolism ; pathology ; Sinusitis ; metabolism ; pathology ; Young Adult

OBJECTIVETo observe the histological characteristics of constructed basement membrane in tissue-engineered skin.

METHODSForskins from circumcision in normal children were obtained with informed consent of the parents, and then the epidermal keratinocytes (KC) and dermal fibroblasts (Fb) were isolated with trypsin and collagenase D digestion in sequence. Tissue engineered skin with composite chitosan was maintained in a submerged state for 3 days, and then at the air-liquid interface. The tissue-engineered skins were fixed in neutral formalin and then embedded in paraffin after culture for 7, 10 and 15 days, respectively for immunohistological examination of the basement membrane component,including the condition of collagen type IV (COL-IV), collagen type VII (COL-VII), and laminin (LN).

RESULTSHE staining showed that the keratinocytes formed a fine stratified squamous epithelium with the presence of basal, spinous, granular and corneous cell layers, and there was various amount of cells in flat and fusiform shape in each layer. It was found that a regular red staining strip situated at the dermal epidermal junction. Positive staining of collagen IV, collagen VII as well as LN was observed by immunohistological examination.

CONCLUSIONThe results suggest that the composite chitosan tissue engineered skin has a good prospect for clinical use because it presents a perfect reconstruction of basement membrane.

Basement Membrane ; cytology ; Cells, Cultured ; Child ; Chitosan ; metabolism ; Collagen Type IV ; metabolism ; Collagen Type VII ; metabolism ; Humans ; Laminin ; metabolism ; Organ Culture Techniques ; Skin, Artificial ; Tissue Engineering ; methods

OBJECTIVETo study the morphologic changes of collagen type III glomerulopathy and to investigate the possible cellular origin for collagen III production.

METHODSLight microscopy, immunofluorescent staining, immunohistochemistry (for collagen I, III and IV and alpha-SMA) and electron microscopy studies on 3 renal biopsy cases of collagen type III glomerulopathy were performed.

RESULTSTwo cases presented with nephrotic syndrome, one of which was associated with systemic hypertension. The third case showed renal impairment and renal hypertension. None had any known family history of renal diseases. Light microscopy showed diffuse thickened glomerular basement membrane and expanded mesangium with deposition of weakly PAS-positive homogeneous material not associated with mesangial cell proliferation. Electron microscopy revealed massive collagen fiber deposits in the subendothelial spaces and mesangium. The mesangial cells also contained bundles of microfilaments in the subplasmalemmal regions. Immunohistochemically, the diffuse positivity for type III collagen corresponded to the homogeneous material seen under light microscopy. The staining for type I and IV collagens was negative. Alpha-SMA was expressed in many mesangial cells.

CONCLUSIONSThe diagnosis of collagen type III glomerulopathy can be made on the basis of detailed morphologic examination and ancillary investigations. It is possible that activated mesangial cells may be the cellular origin of collagen III.

Actins ; metabolism ; Adult ; Collagen Type III ; metabolism ; Female ; Glomerular Basement Membrane ; pathology ; ultrastructure ; Glomerulonephritis ; metabolism ; pathology ; Humans ; Male ; Mesangial Cells ; metabolism ; pathology ; Middle Aged

An early feature of diabetic nephropathy is the alteration of the glomerular basement membrane (GBM), which may result in microalbuminuria, subsequent macroproteinuria, and eventual chronic renal failure. Although type IV collagen is the main component of thickened GBM in diabetic nephropathy, cellular metabolism of each alpha chains of type IV collagen has not been well studied. To investigate the regulation of alpha(IV) chains in diabetic conditions, we examined whether glucose and advanced glycosylation endproduct (AGE) regulate the metabolism of each alpha(IV) chains in the diabetic tissue and glomerular epithelial cells (GEpC). Glomerular collagen alpha3(IV) and alpha5(IV) chains protein were higher and more intense in immunofluorescence staining according to diabetic durations compared to controls. In vitro, mainly high glucose and partly AGE usually increased total collagen protein of GEpC by [3H]-proline incorporation assay and each alpha(IV) chain proteins including alpha1(IV), alpha3(IV), and alpha5(IV) in time-dependent and subchain-specific manners. However, the changes of each alpha(IV) chains mRNA expression was not well correlated to the those of each chain proteins. The present findings suggest that the metabolism of individual alpha(IV) chains of GBM is differentially regulated in diabetic conditions and those changes might be induced not only by transcriptional level but also by post-translational modifications.
Animals ; Cells, Cultured ; Collagen Type IV/genetics/*metabolism/physiology ; Diabetic Nephropathies/*metabolism ; Epithelial Cells/*metabolism ; Glomerular Basement Membrane/metabolism ; Glucose/metabolism ; Glycosylation End Products, Advanced/metabolism ; Male ; Podocytes/*metabolism ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley