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Biomedical subjects

K Sarkar

Publications and source records attributed to K Sarkar.

At least 19 recordsLinked to original sources
PubMed1992

Periarticular soft tissue conditions causing pain in the shoulder.

Pain originating in periarticular soft tissues of the shoulder is a common clinical problem among the aged patients of both sexes, but it has become increasingly frequent in young individuals because of a health-oriented life style. In the past year, a considerable progress has been made in diagnosing these conditions, especially with the aid of magnetic resonance imaging. Our understanding of the pathogenesis of these conditions, however, has advanced very little, and we hope that more efforts will be devoted in the future to elucidate how the periarticular soft tissues of the shoulder react to diverse injuries they are exposed to.

Humans↗
PubMed1991

Usefulness of a new technique for hind limb immobilization in rats for the study of tendon healing.

To study wound repair in rat Achilles tendon, we utilized a novel surgical method for immobilizing only one hind limb. In this technique, the femoral vessels were preserved while the skin, muscles, nerves and the shaft for the femur were transected. The limb was then rotated and sutured to lie on the posterolateral flank of the animal. The recovery was prompt and the procedure affected the routine growth and metabolism of the animal minimally throughout the period of experimentation. In the immobilized limb, healing of the Achilles tendon was studied after subtotal severance in the midsection. The rats were killed at intervals of 1, 2, and 4 weeks postoperatively. After 1 week, the surface of the wound was covered by a thin layer of cells. A gap persisted underneath and showed fibrovascular proliferation at the margins. In 2 weeks, the gap was completely occupied by fibrovascular tissue that was beginning to align along the long axis of the tendon. By the 4th week, remodeling had occurred and the site of the wound had almost blended with the rest of the tendon. We conclude that this new technique of hind limb immobilization causes little stress on the animal, and it can be useful for the study of tendon healing.

Achilles Tendon↗
PubMed1991

Shoulder pain and reflex sympathetic dystrophy.

Shoulder pain has become one of the commonest clinical problems in modern North American society. The pathogenetic mechanisms vary widely, and often times, speculations about the underlying pathology have not been substantiated by investigative studies. In the past year, progress in our knowledge about shoulder pain has not been significant. We discuss the topic by dividing shoulder pain into four categories: 1) shoulder pain of local origin; 2) pain referred to the shoulder; 3) shoulder and neck pain; and 4) shoulder pain and reflex sympathetic dystrophy. It appears that a thorough history taking, an understanding of the psychosocial background of the patient, and a complete physical are equally important in the clinical evaluation of painful shoulders.

Humans↗
PubMed1991

Surgical repair of rotator cuff ruptures. The importance of the subacromial bursa.

We examined biopsy specimens obtained during surgery on 115 patients with complete rotator cuff rupture. The vascularised connective tissue covering the area of rupture and the proliferating cells in the fragmented tendons reflected more of the features of repair than of degeneration and necrosis. The main source of this fibrovascular tissue was the wall of the subacromial bursa. These features clearly indicated a vigorous reparative response which might play an important role in tendon reconstitution and remodelling. We therefore suggest that extensive debridement along with subtotal bursectomy, commonly practised during surgical repair of rotator cuff rupture, should be avoided. Although strong suture margins are essential for good operative results, debridement should be judicious and preserve as much as possible of the bursa and the associated fibrovascular tissue.

Acromioclavicular Joint↗
PubMed1991

Classification and definition of tendinopathies.

The authors have classified tendinopathies into two categories. The majority of the tendinopathies are in the primary category in which lesions arise in the substance of the tendon. The authors emphasize that not all tendinopathies are degenerative in nature. Some primary tendinopathies are reactive, such as calcifying tendinitis.

Athletic Injuries↗
PubMed1990

Mast cells in the rat heart during normal growth and in cardiac hypertrophy.

Mast cells in rat hearts were studied quantitatively during normal postnatal growth and in two types of cardiac hypertrophy. Normally, cardiac mast cell density in 11-12-day-old animals is very low, but increases markedly in the following 2-3 weeks to its highest values, with a subsequent decline toward adult values. At the peak of mast cell density, the percentage of mast cells in close proximity to capillaries is also highest. In adult animals, mast cell counts are significantly higher in the right ventricle than in the left. This relation is preserved even when the right ventricle is hypertrophic, as in rats born at simulated high altitude. Chronic hypertension and swimming have little effect on the mast cell density in rat hearts. Conspicuous changes in the mast cell density at the time of capillary proliferation seem to indicate a special role played by these cells in the formation of new vessels.

Altitude↗
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↗
PubMed1979

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.

Adenoma↗