Mitochondrial inclusions in renal epithelial cells of magnesium-deficient rats

In rats with prolonged magnesium deficiency, paracrystalline inclusions in mitochondria were found frequently in the epithelial cells of the thick ascending limb of Henle, especially in the region of the upper medulla. The inclusions presented a variegated appearance. Some were filamentous aggregates, many had alternating dark and light bands, and others were elongated rectangular densities. They were not found in tubules with calcific deposits where the cells showed degenerative changes. This suggested that the inclusions were probably due to altered cell metabolism and not products of cell degeneration.

Merits and pitfalls in morphological assessment of cardiac growth

The basic principles of quantitative morphological analysis of myocardial tissue are presented. Particular attention is paid to the effects of stimulated cardiac growth on the relationship between cell size and various indices of myocardial capillary supply in pressure-overloaded rat hearts. The importance of adequate sampling and of the number of measurements is stressed with respect to reliable estimation of the mean values but even more for assessment of variability of the measured data. When estimating myocardial capillary supply by average values of capillary density and/or of areas supplied by a single capillary, this crucial information is missing. Therefore the merits of more advanced techniques allowing for the estimation of variability of capillary spacing are critically examined and the significance of their application to myocardial tissue is outlined (method of concentric circles and method of triangular nets). Finally, the importance of variability of capillary spacing on oxygen supply is demonstrated. The variability of capillary spacing alone may affect oxygen supply independently of the average values of intercapillary distance.

Liposarcoma simulating a Baker's cyst: a case study

We present a case of liposarcoma in a 65-year-old man in whom the tumor first appeared as a soft, cystic mass at the medial margin of the left popliteal fossa. The mass simulated a Baker's cyst. The patient remained untreated for almost 7 months from the discovery of the mass. With worsening pressure symptoms, a biopsy was done that confirmed the clinical diagnosis of liposarcoma. The leg was amputated, but the patient died 2 years later with clinical evidence of pulmonary metastasis. By presenting this case report, we stress the importance of carefully investigating for malignancy all masses presenting as a Baker's cyst in persons past middle age.

Ultrastructure of the fibrous tissue surrounding internal fixation devices

The possible bursal nature of the fibrous tissue that develops like a capsule over internal fixation devices was studied ultrastructurally in 13 human and four canine cases. In both species, the basic structural pattern was similar. The capsule had two distinct zones. The superficial compact zone appeared as a pseudomembrane, and consisted of elongated fibrocytes arranged transversely in a collagenous and microfilamentous matrix. In the deep zone, the cytoplasm and its constituents of connective tissue cells varied from meager to abundant. The structural organization of the capsule as well as its cellular characteristics did not conform to the specificities of an adventitious bursa. The capsular tissue did not appear to be affected by such host factors as age; implant alloy composition; the type of the underlying bone or its abnormalities; duration of implantation, or superficial or deep location of the metal device. Inflammation rarely occurred in the capsular soft tissue, including those cases where pain developed over the implants following an uneventful bone union. Because metal implants do not induce formation of adventitious bursa, pain over an uncomplicated implant is not likely to be due to a bursitis.

Embryo resorption following administration of steroidal compounds to rats in mid pregnancy

In the course of experiments on the effects of anabolic steroids on the myocardium of rat conceptuses, we found that subcutaneous implantation of 10 mg of estradiol, Dianabol or testosterone to rats in mid pregnancy, resulted in embryo resorption. Placental tissue was identified only in estradiol-treated rats which also demonstrated a large amount of serosanguineous fluid that dilated the horns considerably. The yellow nodules of placental attachment sites were represented histologically by cellular and vascular proliferations between the inner and outer layers of the myometrium. The nodular aggregates of cells had variable features according to the steroid administered. Neither decidual cells nor metrial glands that are reported to be the constituents of placental attachment sites were seen in our material. We conclude that anabolic steroids are potent agents for embryo resorption, and that the cells in the nodules of placental attachment sites are likely to be derived from the myometrium.

Lead-induced early lesions in the brain of the chick embryo

A single dose consisting of a solution of lead nitrate containing 1 mg lead in 0.1 ml distilled water was injected into the air chamber of chicken eggs on the tenth day of incubation. The injected embryos were killed 24, 48, or 72 hours after the injection. Control embryos were injected with a similar volume of distilled water or of an equimolar calcium nitrate solution on the tenth day and killed 72 hours after. Portions of the optic lobes were processed for their electron microscopic study. Multiple hemorrhagic foci appeared 24 hours after the administration of lead. Red blood cells were found to exit the blood vessels through the spaces between otherwise normal-looking endothelial cells; tight junctions were always found blocking the interendothelial spaces except during the migration of red blood cells through them. Vacuolization of the cytoplasm and mitochondrial swelling and disorganization were observed in the endothelial cells only during the third day after the injection. Similarly, histological and ultrastructural alterations of nerve cells were only found on the third day after the treatment. Hemorrhagic foci were never found in control embryos. Our observations are consistent with the idea that the hemorrhages constitute the primary lesion produced by lead. They also suggest that the hemorrhages are not the result of rupture of previously altered endothelial walls but occur by diapedesis through the interendothelial clefts.

Effects of ureteral ligation on renal medullary lesions of potassium depletion

In diet-induced potassium depleted rats, tissue potassium content of the renal medulla decreases and membrane-bound droplets form in the cytoplasm of medullary cells. To elucidate the interrelationship between medullary potassium concentration and intracytoplasmic droplets, ligation of the left ureter was performed on rats deprived of potassium for 2 weeks. Our results show that, even in the absence of supplemental potassium provision to the animal, a unilateral rise in tissue potassium of the ligated left kidney was significant. After 4 days of ligation, the left medullary potassium was 41.96 +/- 0.79 mEq/100 g dry weight compared to 32.51 +/- 0.84 mEq/100 g dry weight (P less than 0.001) of medullary potassium in the non-ligated right kidney. The rise in tissue potassium in the left kidney coincided with the dissolution of intracytoplasmic droplets. We conclude, that mechanical obstruction to urinary flow can dissolve storage droplets in medullary cells and that the lysis of droplets is made possible by the increase in medullary tissue potassium content.

Differentiation of bones and skeletal muscles in chick embryos cultured on albumen

Chick embryos were cultured in hemispheric dishes containing 25 ml fresh albumen. The addition of albumen, known to the relatively poor in free calcium, increased the deficit of calcium regularly observed in embryos cultured with other methods. In spite of this, the embryos survived and differentiated adequately for prolonged periods of time. Most of the cultured embryos presented malformations of the long bones of the limbs consisting of bowing and exuberant growth of bone trabeculae in the concavity of the bend. Block staining with alizarin showed that bones were undermineralized at the time in which bending occurred. Leg muscles differentiated adequately as judged from their electron microscopical observation. It is concluded that the malformations result from the action of normal muscles on undermineralized bones. The growth of bone trabeculae at the concavity of the bend probably results from the piezoelectrical stimulus produced by the bending of the bones. The concentrations of both the ionized and bound fractions of blood calcium were significantly reduced in the cultures. The system appears to constitute an adequate model for further explorations on the effects of prolonged hypocalcemia on the differentiation of different tissues and organs.

The influence of potassium depletion on cardiac growth response to pressure overload

Previous studies have reported that potassium depletion arrests both body and heart growth, and that aortic ligation can induce myocardial potassium loss. To examine the effects of potassium depletion on the cardiac growth response to an increase in pressure load, we induced severe potassium depletion in rats by dietary means for 3 weeks and then subjected them to aortic ligation. 3 weeks following ligation and after a total of 6 weeks of continued potassium deprivation, the animals were sacrificed. Our results show that after aortic ligation the left ventricular weight in potassium depleted rats significantly increased by an average of 155 mg, a value which was somewhat less than the 208-mg increase observed in normokalemic animals. The presence of focal myocardial necrosis in hypokalemic rats, accordingly, did not appear to prevent the increase in ventricular mass induced by augmented pressure load. Furthermore, despite marked reduction in skeletal muscle potassium content there was no decrease in the myocardial potassium content even after aortic ligation. We conclude that profound dietary potassium depletion for a prolonged period of 6 weeks does not impede the cardiac growth response to an increase in pressure load.

Ultrastructure of the subacromial bursa in painful shoulder syndromes

In order to determine if inflammation of the subacromial bursa or "bursitis" is as common an occurrence as believed in painful conditions of the shoulder, eight bursae were obtained during surgery from 3 cases of calcifying tendinitis, 2 of tight coracoacromial ligament, 2 of rotator cuff tear and 1 of acromioclavicular osteoarthritis. In the cases of calcifying tendinitis, tight coracoacronial ligament and rotator cuff tear the morphological changes mainly consisted of a numerical increase in cells throughout the bursal wall along with proliferation of endothelial cells in the vascular channels. All of the cells including the endothelial had densely packed, intermediate type filaments in their cytoplasm but no appreciable diminution of metabolic organelles. Lipid droplets were abundant in the extracellular connective tissue of the bursae from the cases with rotator cuff tear. In contrast to the other cases, the bursa from the case of acromioclavicular osteoarthritis showed widespread fibrin deposition in association with cell necrosis. In none of the cases did inflammatory leukocytic cells infiltrate bursal tissue. We conclude, that the subacromial bursa tends to undergo proliferative or degenerative changes in rotator cuff tendinopathies but bursal inflammation with polymorphonuclear cell infiltrate does not occur commonly.

[Significance of density and demarcation of calcifications in calcifying tendinitis (author's transl)]

Calcification of tendons can be either degenerative and progressive in nature or reactive and selfhealing. Radiologic examinations permit to distinguish between both kinds. The reactive calcification, known also as calcifying tendinitis, passes through two main phases, the formative and the resorptive phase. Since treatment is different for each phase, their roentgenologic distinction is important. Dense, well demarcated and homogenous calcifications indicate the presence of a formative phase whereas less dense, ill defined and fluffy deposits point toward an ongoing resorption.

Calcifying tendinitis of the shoulder: prognostic value of clinical, histologic, and radiologic features in 57 surgically treated cases

Calcifying tendinitis of the shoulder was studied in 57 patients before and after surgical removal of the calcified material. Many patients with an acute flare of pain prior to surgery also had a "fluffy" calcific deposit on radiograph and histologic evidence of calcium resorption. Conversely, patients with no acute preoperative symptom flare were more likely to have a sharply "defined" calcific deposit on radiograph and less histologic evidence of calcium resorption. Fully 30% of the patients continued to have shoulder pain for more than 12 weeks postoperatively. There were no clinical, radiologic or histologic features which distinguished these patients from those who were symptom free within 6 weeks postoperatively.

Rotator cuff tears: the role of surgery

The indications for operative intervention in patients with rotator cuff tears and the reasonable expectations of such surgery are not well defined. This retrospective study of 37 such patients treated operatively at Ottawa General Hospital showed good results in 65% of cases. However, efforts to re-establish continuity of the cuff did not always result in a permanent cuff reconstruction. The persisting defect did not impede functional recovery as long as the edges of the tear were debrided along with division of the coracoacromial ligament, acromioplasty, or excision of osteophytes at the greater tuberosity. Impingement plays a major role in the disability associated with this condition.

Impairment of testicular maturation in potassium depleted pre-pubertal rats

When maintained on a potassium deficient diet 21 day-old weanling rats ceased to grow. At the end of 3 weeks, the testes were small and the diameter of seminiferous tubules was reduced. The reduction of the tubular diameter resulted mainly from a decrease in the number of cells, chiefly spermatids. An occasional tubule contained a few scattered spermatozoa. Ultrastructurally, the cytoplasm of Sertoli cells contained an increased number of lipid droplets as well as phagocytosed degenerative cells. Spermatids, conspicuously fewer in number, showed abnormal forms and did not mature beyond the early acrosomic phase. It appeared then, that potassium deficiency in immature rats not only arrested growth but largely prevented spermatogenesis. This probably resulted from a widespread inhibition of pituitary trophin function. Also, the deleterious effects on spermatids could be due to local lack of potassium which is present in high concentration in normal seminiferous tubular lumen.

The ultrastructure of nephrocalcinosis induced in chicks by Cestrum diurnum leaves

Powdered Cestrum diurnum leaves, mixed with two diets differing in calcium and phosphorus contents, produced nephrocalcinosis in young chicks regardless of serum calcium elevation. The calcific deposits, found in both proximal and distal portions of cortical tubules, began either in the cytoplasm or in lysosomal bodies as a unilaminar spheroid structure containing apatite crystals. The ultrastructural characteristics of intraluminal concretions suggested that they were formed intracellularly but later were extruded into the lumen. The extent of calcific deposits increased with duration and with hypercalcemia. Although Cestrum contains an analog of 1,25-dihydroxycholecalciferol, neither mitochondria nor basal lamina contained calcific deposits described in nephrocalcinosis secondary to hypervitaminosis D.

Ultrastructure of the common extensor tendon in tennis elbow

In patients with tennis elbow, the common extensor tendon showed a pronounced reactive change consisting of mesenchymal cell proliferation along with aggregates of newly formed vascular channels. When studied ultrastructurally, many of the mesenchymal cells adjacent to the vascular channels were surrounded by a basal lamina, which is not normally seen around tenocytes. The cytoplasm of these cells showed features of both endothelial cells and tenocytes. It thus appeared, that the endothelial cells of the newly formed vascular channels were the source of proliferating mesenchymal cells differentiating toward tenocytes, and together they represented an intrinsic healing mechanism in the tendon.

Renal oncocytoma. Study of eight cases

Eight renal oncocytomas are described. Clinical manifestations were present in 3 cases, with hematuria occurring in 2 and flank pain in 2. Tumors were between 2.5 and 10.0 cm. in diameter and showed considerable variation in histologic pattern. The tan coloration of some tumors may permit a naked-eye distinction from renal cell carcinoma. All tumors appeared to be benign.

Ultrastructural changes in the renal papillary cells of rats during maintenance and repair of profound potassium depletion

In rats with long-term diet-induced potassium depletion, the cytoplasm of markedly enlarged papillary cells was mainly occupied by membrane-bound droplets, many of which acquired massive proportions. Both free and attached ribosomes were decreased, the Golgi apparatus was inconspicuous and there was a paucity of mitochondria. Despite the overwhelming accumulation of droplets with concomitant loss of normal metabolic organelles, cell death did not occur. With potassium repletion, the organelles readily proliferated regardless of the progression of droplet dissolution. The shrinkage of the droplets was accompanied either by disintegration of the limiting membrane or by disappearance of the constituents within an intact membrane. Microtubules were conspicuous in many of the cells undergoing gradual reduction in size. These cytoplasmic changes in renal medullary cells of rats during long-term potassium depletion and immediate post-repletion periods essentially represented the consequences of maintenance and repair of a storage process.

Ultrastructural localization of calcium in calcifying tendinitis

To determine the site of mineralization in calcifying tendinitis, we studied the ultrastructure of tendon fragments that were obtained during surgical interventions on ten patients with that condition. We found that calcification was occurring extracellularly and essentially in areas where the tendon had undergone cartilaginous transformation. Calcific crystals were present in matrix-vesicle-like structures that were seen either singly among collagen fibers or in aggregates. When they were in aggregates, the calcifying vesicles tended to fuse with each other. Thus, the process of mineralization in calcifying tendinitis resembled those calcifying conditions that have already been described in man and animals, both normal and pathological, in which the apatite crystals are initially localized in matrix vesicles.

Minimal medullary droplets in DOCA-induced potassium depletion of rats

When potassium depletion is induced in rats administering desoxycorticosterone acetate instead of restricting potassium in the diet, the droplet accumulation in medullary cells is reduced, despite the similar degree and duration of potassium depletion. This finding indicates that the accumulation of droplets is more dependent on the inducing agent than on the severity or duration of potassium depletion.