Keiki Hayashi

Transferrin Receptor Expression in Normal, Iron‐deficient and Iron‐overloaded Rats

The distribution of transferrin receptor (TfR) positive cells and their staining intensity were examined in the liver, duodenum, pancreas, spleen, kidney and brain of iron deficient, iron‐overloaded and normal Wistar rats to elucidate the regulatory effects of iron on TfR expression in vivo. Iron deficiency was produced by an iron deficient food and water regimen, and iron overload by repeated intraperitoneal injections of ferric nitrilotriacetate (Fe3‐NTA) for 12 weeks. In iron deficient rats, levels of hemoglobin (Hb= 5.9 ± 0.7) and serum iron (Sl = 29.9 ± 4.4) were lower, and total iron binding capacity (TIBC = 624.4 ± 72.7) was higher than in normal rats (Hb = 15.6 ± 0.9, Sl = 206.5 # 20.5, TIBC = 416.0 ± 56.0), and Wee versa for SI (217.7 ± 15.5) and TIBC (307.1 ± M45.4) in iron‐overloaded rats. In normal rats, TfR positive granules were observed in hepatocytes and Kupffer cells of the liver, absorptive epithelium of the duodenum, acinar and Langerhans islet cells of the pancreas, macrophages and red pulp erythro‐blasts of the spleen, and distal convoluted tubular epithelium of the kidney. Although the tissue distribution pattern of TfR positive cells was similar in normal, iron deficient and iron overloaded rats, the staining intensity and number of TfR positive cells were obviously higher in iron deficient, and lower in iron overloaded rats. We conclude that TfR expression is negatively regulated by the tissue concentration of iron. Acta Pathol Jpn 39: 759‐764, 1989.

Selective iron deposition in pancreatic islet B cells of transfusional iron‐overloaded autopsy cases

Pancreatic islets of 36 autopsy cases with transfusional iron‐overload were examined. Immunohistochemical and histo‐chemical stainings were used to clarify the relationship between blood transfusion and iron deposition in the islet. Disease of the lymphohemopoietic system (leukemia, lymphoma, aplastic anemia) or liver (carcinoma and/or cirrhosis) accounted for 86.1% of the patients’main diagnosis. Sixteen of them had slight hemosiderin deposition (Group 1), twenty cases had severe hemosiderin deposition (Group 2). Another ten cases were used as controls (Group 3). The cases had a similar age distribution to Group 1 and 2, with neither blood transfusion nor hemosiderin deposition. The volume of blood transfusion was 6.1 ± 3.6, 17.5 ± 12.2 L for Groups 1 and 2, respectively. The plasma glucose was 137.8 + 54.4 and 170.6 ± 108.4 mg/dL, respectively. Four cases in Group 1 and 14 cases in Group 2 had glycosuria. The number of islet cells with hemosiderin increased with the enlargement of transfusion volume (r= 0.664, P± 0.001). Plasma glucose also related with the percentage of hemosiderin positive islet cell (r = 0.386, P < 0.025). In severely iron‐overloaded cases, hemosiderin was selectively deposited in B cells of the islet.

DISSEMINATED INTRAVASGULAR COAGULATION (DIC)

Renal tissues of 208 autopsied cases were examined. Malignant neoplasm with hematological malignancies often accompanied DIG. Tissue sections were stained with hematoxylin and eosin and Mallorys phosphotungstic acid hematoxylin (PTAH), and were applied for immunoperoxidase method (IP), using antisera against human fibrinogen, FDP‐D and FDP‐E. Histologically in 80 cases (38%) fibrin or fibrinogen related materials (FRMs) were observed in the glomerular capillary or the intratubular area or in both. FRMs were PTAH or IP positive or both in 23 of the 26 cases (88%) clinically diagnosed as DIC. In the remaining three cases anticoagulants probably Interfered with FRMs observation. This study showed the PTAH stain was nonspecific and insensitive to FRMs, and that IP was necessary for a pathological diagnosis of DIC. The presence of FRMs in the renal tubuli is an important finding in confirming DIG. DIC may be present histologically in the absence of clinical DIC symptoms.

Transferrin Receptors and Selective Iron Deposition in Pancreatic B Cells of Iron‐overloaded Rats

Iron overload was produced in Wistar rats by repeated intraperitoneal injections of ferric nitrilotriacetate (Fe3+‐NTA) for one to six months. Pancreatic tissues from these iron‐overloaded rats and untreated controls were examined for insulin (for B cells), glucagon (for A cells), transferrin receptor (TfR), transferrin (Tf) and ferritin (Ft) using immunohistochemical methods, and for iron by histochemical Berlin blue staining. In the islets of iron‐overloaded rats, increased Ft staining appeared prior to deposition of Berlin blue‐stainable iron, and the staining intensity of Ft and iron was stronger in B cells than in A cells. In the islets of untreated control rats, the staining intensity of TfR was stronger in B cells than in A cells. TfR staining of the islets was weaker in iron‐overloaded rats than in the controls. These findings suggest that 1) iron uptake by islet cells in vivo is regulated and mediated by TfR, 2) intracytoplasmic Ft transforms into stainable iron in iron‐overloaded rats, and 3) predominance of TfR expression in B cells may result in selective deposition of iron and predispose B cells to damage and diabetes mellitus in iron‐overloaded rats. Acta Pathol Jpn 41: 647–652, 1991.

The anatomy of the P lymphocyte

This paper describes the basic morphologic criteria for identifying the P lymphocyte. The P cell is a stimulated atypical lymphocyte that is found in schizophrenics and some of their relatives. This cell is suggested as a tentative laboratory indicator of the schizophrenia process. The main identifying features of the cell are its high cytoplasmic basophilia and leptochromatic nuclear structure. Furthermore, the cytoplasm often contains vacuoles and the nuclear shape is often irregular with one or more nucleoli visible. Color micrographs are used to illustrate the cell features.

Pancreatic Islets after Repeated Injection of Fe3+‐NTA An Ultrastructural Study of Diabetic Rats

Pancreatic islet cells were examined ultrastructurally in rats after repeated intraperitoneal injections of ferric nitrilotriacetate (Fe3+‐ NTA) to produce a model of bronze diabetes. Despite diabetic signs such as glycosuria and ketouria, no ultrastructural alterations were found in islet cells up to 90 days after the beginning of the Fe3+‐NTA injections. After 120 days, however, degenerative changes appeared, with most B cells of the islets of Langerhans showing clumped nuclear chromatin, a dilated nuclear envelope, vacuolated and dilated endoplasmic reticulum, and a loss of cell polarization toward the capillary lumen. The cells contained a number of light secretory granules with an electron‐lucent core and a narrow halo. Numerous electron‐dense ferritin‐like particles were also found in the cytoplasmic matrix, and A and D cells were almost intact. Repeated venesection therapy of rats injected with Fe3+‐NTA for 120 days resulted in an increase of morphologically normal B cells with a smaller number of necrotizing cells. This process was accompanied by recovery from diabetic symptoms. The toxic effect of injected iron on B cells was thus clarified.

Transferrin receptor distribution and iron deposition in the hepatic lobule of iron-overloaded rats

Under the condition of obvious iron‐overload, there is a zonal hernoeiderin (iron) deposition in hepatic lobules. The deposition is heavtest in the periporfal (zone 1) and lightest in the perivenws (zone 3) hepatocytes. However, the mechanism for this pattern of iron deposition is obscure. Hepatic tissues from control, iron‐deficlent or ironoverloaded Wistar rats me used to study its pathogenesis. iron‐deficiency was Induced by a low Iron regimen. Ironoverload was produced by repeated intraperitoneal injections of ferric nitrilotriace‐We (Fe3+‐NTA) for 1–4 months. Liver tissues of the rats were lmmunohistochemically and histochemically stained for tmnaferrin receptor (TfR), transferrin (Tf), ferritin (Ft), and iron. The staining intensity of TfR, Tf and Ft increased in hepatocytes of iron‐deflctent rats and decreased in that of the iromverloaded in comparison with the control rats. TfR atalning was strong in zone 1, with gradual transition into weak staining in zone 3 hepatocytes of the rat liver. TfR located primarily on the hepatocyte membrane. Tf had both membranous and cytoplasmic distribution. Many hepatocytes in group B had strong cytoplasmic Tf staining. Conversely, only a few hepatocytes had weakly stained cytoplasmic Tf in group C. Hepatocytes and Kupffer cells were Ft positive in control rats. Ft was distributed only in the cytoplasm. The staining intensity of Ft was stronger in zone 3 than in zone 1 hepatocytes of iron‐deficient rats. In iron‐overloaded rats, the iron deposition was severe in zone 1 and mild in zone 3 hepatocytes. These findings suggest that uptake of iron into hepatocytes in vivo is regulated and mediated by TfR and Tf. Gradient TfR distribution from zone 1 to 3 hepatocytes and active TfR‐Tf mediated iron uptake resuited in the zonal iron deposition in the hepatic lobule of iron‐overloaded rats.

PARTICIPATION OF BONE MARROW STROMAL CELLS IN HEMOPOIETIC RECOVERY OF RATS IRRADIATED AND THEN PARABIOSED WITH A NON‐IRRADIATED LITTER MATE

A light microscopical study on the recovery process after lethal irradiation and parabiosis has been made.6 Electron microscopically, in the bone marrow of lethally irradiated rats, hemorrhage occurred due to detachment of sinus endothelial cells. Afterwards, reticulum cells with small intracytoplasmic lipid droplets appeared. On day 3, these cells were rapidly replaced by the reticulum cells with large lipid droplets, and resulted in fatty marrow within 7 days. Spindle‐shaped fibroblastoid reticulum cells were also observed. In the bone marrow of lethally irradiated rats parabiosed with non‐treated litter mates, hemopoiesis was initiated by adhesion of nucleated blood cells to intricated fine cytoplasmic pseudopods of fat‐storage cells. On days 3 to 5, in parallel with progressive hemopoietic recovery, flbroblastoid and reticulum cells with large lipid droplets decreased whereas those with small droplets increased. On day 8, reticulum cells with lipid droplets were seldom seen, and hemopoietic distribution became the same as normal. These results suggested that bone marrow stromal cells, namely reticulum, fat‐storage, and flbroblastoid cells share a common cellular origin, and also that they regain their structure and function when fat‐storage cells were placed in contact with hemopoietic precursor cells.

An immunohistochemical study of experimental disseminated intravascular coagulation (DIC).

The experiment was focused on clarifying changes in fibrin or fibrinogen related materials (FRMs) in blood, urine, and renal tissues of rats with disseminated intravascular coagulation (DIC). DIC was induced by a continuous infusion of massive volume of physiologic saline (100 ml) immediately after endotoxin injection. FRM response was checked by biochemical and histo‐chemical examinations at various intervals. In the blood of DIC rats, platelet and fibrinogen levels initially decreased, followed by an increasing plasma fibrin degradation products (FDP). Parallel with elevation of blood FDP the percentage of glomeruli with FRMs increased. Thereafter, FRMs were observed in renal tubuli and urine. Our observations indicated that FRMs in renal tubuli were derived from glomerular capillaries via Bowmans space. In conclusion, in DIC the immunoenzymehistochemical (IEH) procedure appeared necessary for an accurate pathological diagnosis, and the presence of FRMs in renal tubuli appeared to be an important finding even in absence of FRMs in glomeruli.