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Biomedical subjects

K Sarkar

Publications and source records attributed to K Sarkar.

At least 55 records · Page 3Linked to original sources
PubMed1990

An algorithm for shoulder pain caused by soft-tissue disorders.

Painful shoulders are commonly caused by disorders of periarticular soft tissues, especially rotator cuff tendinopathies. In contrast to arthritic conditions of the shoulder, soft-tissue disorders can present a diagnostic dilemma that often results in the use of such nonspecific or unproved terminologies as periarthritis or bursitis. To promote an efficient use of investigative studies necessary to arrive at a proper diagnosis, an algorithm can serve as a guide for clinicians in the diagnosis and management of common, nonarthritic conditions of painful shoulders.

Algorithms↗
PubMed1990

The ultrastructure of the coracoacromial ligament in patients with chronic impingement syndrome.

In an ultrastructural study of the cells and matrix of the coracoacromial ligament (CAL) in 11 patients with impingement syndrome (IS), the cells appeared variegated, in contrast to those in normal CALs. Many showed degenerative changes such as lipid inclusions in the cytoplasms or swelling of cytoplasmic organelles, especially in the vicinity of fibrin exudate where the collagenous matrix disappeared. However, some cells had increased cytoplasmic organelles, including an elaborate Golgi apparatus, indicating enhanced synthetic activity. The matrix, instead of consisting of packed collagenous fibers of fairly uniform diameter as seen in the normal CAL, contained collagen fibers of varying diameters and microfibrils. The ultrastructural features of both the cells and the matrix were suggestive of chronic effects of strain on the ligament. In patients with chronic IS, the CAL has been implicated as the likely cause of impingement when no significant bony or articular abnormality exists. This was not substantiated by the present findings. The changes in the CAL in IS are possibly secondary, and are probably induced by alterations in soft-tissue structures of the subacromial compartment.

Acromion↗
PubMed1988

The role of the coracoacromial ligament in the impingement syndrome. A clinical, radiological and histological study.

Seventeen patients with a painful arc syndrome and tenderness over the coracoacromial ligament were selected to demonstrate the changes in the coracoacromial ligament in the impingement syndrome. Plain X-ray examination was normal and a preoperative subacromial bursogram demonstrated impingement in only three out of 17 patients. However, at operation the subacromial space under the coracoacromial ligament, which normally admits the tip of the little finger, appeared unusually tight and barely accessible in 15 out of 17 patients. Histological examination of the biopsied ligament showed degenerative changes but no increase in fibrous tissue. We conclude that in the absence of bony overgrowth the initial change is an increased volume of the soft tissues in the subacromial space. Consequently, the space is compromised by the swelling of its contents, which exert abnormal pressure on the overlying coracoacromial ligament and cause degenerative changes in the ligament. The symptoms of impingement appear because of the unyielding nature of the coracoacromial ligament. Subacromial bursography may not be a reliable test when the coracoacromial ligament is the site of impingement.

Adult↗
PubMed1988

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.

Animals↗
PubMed1986

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.

Aged↗
PubMed1986

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.

Animals↗
PubMed1986

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.

Adipose Tissue↗
PubMed1986

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.

Animals↗
PubMed1985

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.

Animals↗
PubMed1983

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.

Adult↗
PubMed1983

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.

Animals↗
PubMed1983

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.

Albumins↗
PubMed1982

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.

Adult↗
PubMed1982

[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.

Calcinosis↗
PubMed1981

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.

Animals↗
PubMed1981

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.

Animals↗