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Biomedical subjects

G Osawa

Publications and source records attributed to G Osawa.

At least 37 records · Page 2Linked to original sources
PubMed1996

The COL4A5 gene in Japanese Alport syndrome patients: spectrum of mutations of all exons. The Japanese Alport Network.

To determine the spectrum of mutations of the COL4A5 gene encoding type IV collagen among Japanese Alport syndrome (AS) patients, 60 unrelated patients (47 males and 13 females) from all over the country were recruited. Screening for mutations in all the exons (1 to 51) of the COL4A5 gene was carried out by PCR-SSCP analysis. A mobility shift was observed in 22 of 60 patients, and their genomic DNA were analyzed by the direct sequence method and using cloned ssDNA. Nine of these had missense mutations in the collagenous domain (in exons 39, 37, 31, 29, 28, 27, 21, 20, 19). Eight of these mutations were observed in a codon of glycine residue. Two were altered to arginine, two to valine, two to glutamic acid and two to aspartic acid. The other missense mutation was a change from isoleucine to serine in a interruption region. Five patients had small size base deletions and one had a 4 bp insertion resulting in frameshift (in exons 49, 41, 19, 14, 13). Three had a splice site mutation (in exons 49, 47, 27). One had a nonsense mutation (in exon 17). These mutations seemed to be pathogenic, but the phenotype, which includes extrarenal manifestations, can vary with respect to both expression and severity. The remaining mutations were three silent ones (in exons 19, 39, 46). In addition, major gene rearrangement seemed to be rare in Japanese AS patients.

Adult↗
PubMed1996

Relationship between COL4A5 gene mutation and distribution of type IV collagen in male X-linked Alport syndrome. Japanese Alport Network.

The renal immunohistochemical distribution of collagen IV chains was studied with a monoclonal antibody series recognizing the alpha 1(IV) to alpha 6(IV) chains in nine males with X-linked Alport syndrome whose COL4A5 mutation had been already identified. Two patients had a deletional mutation, six patients had a missense mutation and one patient had a splicing site mutation. The alpha 3(IV) to alpha 6(IV) chains were completely absent in the renal basement membrane of the two patients with a deletional mutation. On the contrary, in four of six patients with a missense mutation (substitution of a glycine within collagenous domain), antigenecity of the alpha 3(IV) to alpha 5(IV) chains was recognized in the glomerular basement membrane although it was weak. In addition, one of the remaining patients showed a normal histochemical pattern of all type IV collagen chains, while the rest one showed completely absent of the alpha 3(IV) to alpha 5(IV) chains at the same pattern of deletional mutation. One patient with a splice site mutation showed complete absence of the alpha 3(IV) to alpha 5(IV) chains from the glomerular basement membrane, but weak staining of the alpha 5(IV) and alpha 6(IV) chains from the Bowman's capsular basement membrane. Our observations indicated that there is variety in the staining of the alpha 3(IV) to alpha 6(IV) antibodies among male patients with COL4A5, mutations.

Adolescent↗
PubMed1996

Myelofibrosis secondary to renal osteodystrophy.

A hemodialyzed women with secondary hyperparathyroidism who recovered well from myelofibrosis after a total parathyroidectomy with autotransplantation of parathyroid tissue to the forearm (PTx) is described. Before the operation, she had received regular transfusions to maintain an adequate hematocrit even under recombinant human erythropoietin (rhEpo) therapy. She showed splenomegaly and leukoerythroblastosis was present in her peripheral blood. A bone marrow biopsy and bone marrow scintigraphy confirmed the diagnosis of myelofibrosis. After PTx, her hematocrit gradually increased without any transfusion. It has been maintained around 35% now 16 months since the operation. Her spleen has also gradually decreased in size. In addition, no leukoerythroblastosis has been found in the peripheral blood. Serial follow-up scintigraphy of bone marrow revealed a decline in extramedullary hematopoiesis. These findings indicated that her myelofibrosis was the result of secondary hyperparathyroidism, and that this complication is potentially reversible if accurate treatment is given. Physicians dealing with the end-stage renal disease should be aware of this complication to avoid additional transfusions.

Alkaline Phosphatase↗
PubMed1996

A single-base mutation in exon 31 converting glycine 852 to arginine in the collagenous domain in an Alport syndrome patient.

In a family with Alport syndrome, molecular analysis of the COL4A5 gene, which encodes the alpha 5(IV) chain of glomerular basement membrane collagen, revealed a GGA-->AGA change in exon 31, resulting in substitution of an arginine for a glycine in position 852 of the polypeptide chain, between interruptions 16 and 17 of the triple-helical collagenous domain. The mutation causes the MaeI restriction sites, and could be easily diagnosed in the family members through restriction analysis. This one point mutation can be expected to interrupt type IV collagen molecules.

Adult↗
PubMed1996

Congenital psoriasiform erythrokeratodermia with cleidocranial dysplasia, urogenital anomalies and atresia ani.

We describe two siblings with unique psoriasiform erythrokeratodermia associated with cleidocranial dysplasia, urogenital anomalies and atresia ani. The skin lesions were characterized by demarcated psoriasiform erythema with scaling. A skin biopsy revealed small abscesses containing polymorphonuclear leukocytes in the parakeratotic horny layer, elongation of the rete ridges and dermal papillae, and other findings consistent with psoriasis. A reverse-transcription polymerase chain reaction analysis disclosed increased expression of transforming growth factor alpha in the affected skin lesion of one of the siblings as well as in the skin of a patient with psoriasis. It is suggested that these cases are a variant of a congenital form of psoriasiform erythrokeratodermia.

Adolescent↗
PubMed1995

Case report: intraglomerular metastasis with neoplastic cell interposition.

A case is described of an 88-year-old man with lung cancer, nephrotic syndrome, and renal dysfunction who died suddenly of an acute myocardial infarction and whose autopsy revealed many adenocarcinoma cells stacked within glomerular capillary lumina of his kidney, entering into basement membrane zones (ie, neoplastic cell interposition). In addition, glomeruli showed a lobular transformation, doubling of glomerular basement membrane, and electron dense deposits along the glomerular basement membrane. These changes were similar to those of membraneoproliferative glomerulonephritis. The association of intraglomerular metastasis and membranoproliferative glomerulonephritis-like lesions led the authors to speculate that the latter glomerular change might have provided an attractive opportunity for circulating tumor cells to be trapped and grow within the glomerular lumina. This mode of metastasis has not been well-recognized. The authors describe the experience, review the literature, and discuss its possible pathogenesis.

Adenocarcinoma↗
PubMed1995

[A case of renovascular hypertension with nephrotic syndrome].

A 68-year-old male patient with renovascular hypertension (RVHT) and nephrotic syndrome (NS) is described. He was admitted to our hospital for detailed investigation of severe hypertension and massive proteinuria. After admission, a diagnosis of RVHT with a right non-functional kidney and NS was made. Nephrectomy and contralateral renal biopsy were performed for refractory hypertension and detailed investigation of the NS, respectively. The renal biopsy showed focal segmental glomerulosclerosis (FGS) in the left kidney, whereas the nephrectomised kidney exhibited only ischemic change. After the operation, his blood pressure became stable without anti-hypertensive agents, but proteinuria remained in the nephrotic range. Six months later, proteinuria had disappeared and his renal function was stable. These findings suggest that NS and FGS might have resulted from an activated renin-angiotensin-axis and that the prolonged NS was due to severe glomerular injury. Although there have been many reports describing the relationship between RVHT and FGS in an experimental environment, this relationship is very rare in clinical cases. Therefore we present this case to increase understanding of the cause of FGS.

Aged↗