Hayao Nishinakagawa

Renal Lesions in Spontaneous Insulin-dependent Diabetes Mellitus in the Nonobese Diabetic Mouse: Acute Phase of Diabetes

The nonobese diabetic mouse is a model of spontaneous insulin-dependent diabetes mellitus. The present study made longitudinal observations of renal lesions in the acute-progressive phase of diabetic mice 0, 10, 20, 30, and 40 days after onset of diabetes without insulin therapy. Plasma creatinine and blood urea nitrogen concentrations gradually increased after onset of diabetes. Kidney weight increased and plateaued at day 20. Under electron microscopy the glomeruli demonstrated only mild changes on day 40. In the proximal tubules proliferating cell nuclear antigen-positive nuclei and nuclear divisions were increased on days 10 and 20. On day 40 of diabetes, increased periodic acid-Schiff-positive granules, confirmed as lysosomal dense bodies, increased neuronal nitric oxide synthase (nNOS) positive reaction, and decreased periodic acid-Schiff staining in the brush border were observed in the proximal straight tubules. In the juxtaglomerular apparatus stratified macula densa were decreased with time in diabetes compared with the findings on day 0, and this macula densa positively reacted with nNOS. No changes in renin levels were observed. In addition, apoptotic cells were not detected. In conclusion, this research represents the first thorough characterization of acute changes in nonobese diabetic mouse kidneys. The results demonstrated renal hypertrophy and slight glomerular injury in early stages and structural alteration of the proximal straight tubules at later stages during the acute phase of diabetes. Furthermore, increased nNOS may represent one of the pathogenic factors of diabetic nephropathy.

SEXUAL DIMORPHISM OF PROXIMAL STRAIGHT TUBULAR CELLS IN MOUSE KIDNEY

The proximal straight tubular epithelium of the mouse kidney exhibited sexual dimorphism in conventional paraffin sections stained with periodic acid Schiff (PAS) in our preliminary observation. The purpose of this study was to clarify the sex‐dependent structural features in the proximal straight tubular cells of the mouse kidney, and to clarify the effects of sex hormones on this portion of the renal tissue.

Effects of sex hormones on the development of giant lysosomes in the proximal tubules of DBA/2Cr mouse kidney

The DBA/2Cr mouse strain is characterized by giant lysosomes that are located in the proximal convoluted tubules of males and in the proximal straight tubules of females. In the present study, we used light microscopy and electron microscopy to investigate the effects of sex hormones on the development of these giant lysosomes. In the proximal convoluted tubules of males, giant lysosomes (large vacuolar structures observed under light microscopy) disappeared after orchiectomy but reappeared after testosterone treatment. No changes were observed after ovariectomy or estradiol treatment. In the proximal straight tubules of females, giant lysosomes (periodic acid Schiff‐positive giant granules observed under light microscopy) disappeared after ovariectomy but reappeared after estradiol treatment. After orchiectomy and testosterone treatment, the giant lysosomes did not appear. However, a number of small lysosomes (smaller than a nucleus), which were periodic acid Schiff‐positive, increased after orchiectomy and decreased after testosterone treatment. These findings suggest that lysosomes in DBA/2Cr mice are regulated by testosterone or estradiol as follows: (1) in the proximal convoluted tubules, the development of lysosomes is stimulated by testosterone but not by estradiol; (2) in the proximal straight tubules, development of lysosomes is stimulated by estradiol and inhibited by testosterone.

BLOOD SUPPLY TO THE MAMMARY GLAND IN OVARIECTOMIZED MICE

11?e relationship between the duct-alveolus system and the blood vessels of the mam-mary gland was investigated in ovariectomized. ICR-J CL mice.In Experiment I, 64 mice were ovariectomized at 90 days of age and sacrificed 7 to42 days later. Ten normal females were sacrificed at 90 days of age to serve as controls.In Experiment II, 120 immature and mature mice from 20 to 90 days old were ovariec-tomized at 10 days intervals ancl sacrificed at 100 days of age together with [0 intact.female mice serving as controls.All the animals were in.jected with India ink or latex via A. carotis comtnunis sinistra.The 3rd tboracic mammary gland on the right side was stained with carmine to demon-.strate the mammary parenchyma as a whole mount preparation, and the left 3rd thoracicgland was also prepared for histological observation.l. In Experiment I, the mammary gland on the 7th and 14th day after ovariectomyshowed a tendency to regress in the end bud and a part of the lateral bud, but no con-spicuous degeneration of the ductal system. On the other harid, the condition of tlte?duct-associated capillary plexus was similar to that seen in the intact animals, but theblood vessels of the bud were partially involute. An obvious regression of the bud andslender ducts was observed in the mammary gland on the 21st and 28th day after ovariec-tomy. On these days, tl?e ductal capillary plexus was ltardly seen. On the 35th and42nd day after ovariectomy, the mammary gland was composed only of ducts because ofthe obvious involution of the bud. The interlobular ducts were slender. The distal end?duct changed into a saccule-like structure. Although the mammary parenchyma was lowin density of vascularity, the loop-shaped capillary networks in the adipose tissue werecomparable to those sc)en in the intact animals. Furthermore, the mammary parenchyma?of some of the females on the 7th day after ovariectomy slaowed as much regression asthat of tltefemales on the 35th day after ovariectomy.2. In Experiment II, the unammary gland of 100-day-extend

キュウシュウノウサギ, アマミノクロウザキおよび家兎JW-NIBSの骨の計測値について:II. 前肢骨および後肢骨

The bones of the thoracic and pelvic limbs of Lepus brachyurus brachyurus, Pentalagus furnessi and Oryctolagus cuniculus (strain: JW-NIBS) were investigated morphologically and osteometrically. The results obtained are summarized as follows. 1. The length of long bones in limbs is the largest in Lepus except the distal phalanges, next in JW-NIBS and the smallest in Pentalagus. 2. The breadth of long bones in limbs except the distal phalanges is generally larger in Pentalagus than in Lepus and JW-NIBS, and not significantly different between Lepus and JW-NIBS. 3. The area of articular surface in each limb bone is most extensive in Pentalagus. 4. The distal phalanges of Pentalagus are strong and heavy, the largest in length and the widest in breadth, while those of JW-NIBS are small and light. 5. The distances between the right and left cranial ventral iliac spines, acetabula or ischiatic tuberosities in hip bones are longer in the female than in the male. These differences in sex are distinct in Lepus and JW-NIBS and not clear in Pentalagus.