In vivo evaluation of autologous cartilage fragment-loaded scaffolds implanted into equine articular defects and compared with autologous chondrocyte implantation

BACKGROUND

Current autologous chondrocyte implantation (ACI) techniques require 2 surgical procedures: 1 for cell harvest and 1 for reimplantation of cultured cells. A 1-step procedure is more desirable.

PURPOSE

A 1-step surgical procedure using autologous cartilage fragments on a polydioxanone scaffold, or CAIS (cartilage autograft implantation system), in a clinically relevant defect (15-mm diameter) within equine femoral trochlea was compared with a 2-step ACI technique as well as with empty defects and defects with polydioxanone foam scaffolds alone.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten skeletally mature horses were used. Articular cartilage from the lateral trochlea of the femur was harvested arthroscopically (n = 5), and chondrocytes were cultured on small intestinal submucosa to produce ACI constructs. The CAIS procedure had cartilage harvested during defect creation to prepare minced cartilage on polydioxanone-reinforced foam. The ACI and CAIS constructs were placed in defects using polydioxanone/polyglycolic acid staples. Defects were examined arthroscopically at 4, 8, and 12 months and with gross, histological, and immunohistochemical examination at 12 months.

RESULTS

Arthroscopic, histologic, and immunohistochemistry results show superiority of both implantation techniques (ACI and CAIS) compared with empty defects and defects with polydioxanone foam alone, with CAIS having the highest score.

CONCLUSION

This is the first demonstration of long-term healing with strenuous exercise using ACI and CAIS in a critically sized defect.

CLINICAL RELEVANCE

Given these results with the CAIS procedure, testing in human patients is the next logical step (a phase 1 human clinical study has proceeded from this work).

Elevated high-sensitivity C-reactive protein levels are associated with local inflammatory findings in patients with osteoarthritis

OBJECTIVE

C-reactive protein (CRP) has been associated with disease progression in patients with osteoarthritis (OA), but the reasons for this remain unclear. We hypothesized that higher CRP would be related to local inflammatory findings in the joints of patients with OA.

METHODS

Plasma and synovial membrane specimens from 54 OA patients undergoing total hip or knee arthroplasty or arthroscopy were obtained. Synovial fluid was obtained from 25 of these patients. Hematoxylin and eosin stained synovial membrane sections were scored for degree of inflammatory cell infiltration. Plasma high-sensitivity CRP (hsCRP) levels, and serum and synovial fluid interleukin (IL)-6 and IL-1beta levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Fifty-seven percent of patients with idiopathic OA had inflammatory infiltrates within the synovial membrane. The mean hsCRP level in patients with inflammatory infiltrates was significantly higher than those without inflammation (4.7 +/- 5.0 mg/L vs 1.7 +/- 3.6 mg/L, P = 0.003). There were significant correlations between hsCRP levels and synovial fluid IL-6 (r = 0.64, P = 0.0006), degree of synovial inflammatory infiltration (r = 0.43, P = 0.002), and body mass index (r = 0.31, P = 0.02). Multivariate analysis indicated that only degree of inflammatory infiltrate was significantly associated with hsCRP level (P = 0.026).

CONCLUSION

These results suggest that systemic hsCRP levels reflect synovial inflammation in OA patients, perhaps by means of synovial IL-6 production. Future studies are needed to clarify how these infiltrates and their products may contribute to disease pathogenesis.

The anatomy and histology of the rotator interval capsule of the shoulder

Forty-seven rotator interval regions from fetuses and 10 fresh-frozen rotator interval regions from adult cadavers were evaluated by gross dissection and light microscopy. Specimens from adults also were evaluated with ultrasound and magnetic resonance imaging. An analysis of 37 fetal specimens (> 14 weeks gestation) revealed two rotator interval types: Type I (9 of 37) was defined by a contiguous bridge of capsule consisting of poorly organized collagen fibers. A Type II rotator interval (28 of 37) had a complete defect covered by only a thin layer of synovium. Similar to the Type II rotator interval in the fetus, a rotator interval defect was present in six of eight specimens from adults. Histologically, the capsular tissue within the rotator interval consisted of poorly organized collagen fibers in specimens from the fetus and adult. Maximal opening of the rotator interval was seen by ultrasound with internal rotation and downward traction of the hyperextended arm in the coronal, oblique, and sagittal planes. Magnetic resonance imaging of the rotator interval region permitted anatomic evaluation. The complete absence of tissue in 28 of 37 fetuses suggests that the rotator interval defect is congenital. The authors recommend that surgeons carefully evaluate the integrity of the tissue within the rotator interval. When rotator interval closure is desired such as in patients with a persistent sulcus sign after arthroscopic stabilization, suturing the edges of more substantial tissue immediately adjacent to the boundaries of the rotator interval region would seem prudent.

Spinal epidural hemangioma related to pregnancy

We report the case of a 39-year-old woman with adolescent idiopathic scoliosis presenting with myelopathy secondary to a spinal epidural hemangioma. MRI showed an epidural soft tissue mass within the spinal canal between T5 and T9 with severe spinal cord compression. Symptoms had a temporal relationship to her pregnancy. Surgical removal of the epidural hemangioma rapidly relieved her symptoms and neurologic deficits. Follow-up examination 2 years later demonstrated normal motor and sensory function, without any neurologic sequelae or progression of deformity.

The prevalence and clinicopathological appearance of extension of osteonecrosis in the femoral head

In about 50% of cases, osteonecrosis of the femoral head is known to occupy more than one site. There is controversy as to whether a single focus may increase in size. We have reviewed 606 consecutive femoral heads which had been surgically removed for osteonecrosis. Extension of osteonecrosis was observed in only two (0.3%) and was confirmed histopathologically by the enlargement of the necrotic segment beyond the repair zone formed for the primary necrosis into the adjacent, previously uninvolved bone. In both cases, the necrotic regions were wedge-shaped and occupied over 80% of the femoral head. It appears that an increase in size is extremely rare and that osteonecrosis is due to a single event. Our findings may be of value in assessing the use of joint-salvage procedures for osteonecrosis of the femoral head.

The prevalence and clinicopathological appearance of extension of osteonecrosis in the femoral head

In about 50% of cases, osteonecrosis of the femoral head is known to occupy more than one site. There is controversy as to whether a single focus may increase in size. We have reviewed 606 consecutive femoral heads which had been surgically removed for osteonecrosis. Extension of osteonecrosis was observed in only two (0.3%) and was confirmed histopathologically by the enlargement of the necrotic segment beyond the repair zone formed for the primary necrosis into the adjacent, previously uninvolved bone. In both cases, the necrotic regions were wedge-shaped and occupied over 80% of the femoral head.

It appears that an increase in size is extremely rare and that osteonecrosis is due to a single event. Our findings may be of value in assessing the use of joint-salvage procedures for osteonecrosis of the femoral head.

Chronic ankle pain caused by osteoid osteoma of the neck of the talus

Five patients with osteoid osteomas of the talar neck were treated at the Hospital for Special Surgery between 1981 and 1992. The course of care leading to definitive diagnosis and treatment was reviewed. All five of the patients had night pain relieved by aspirin or nonsteroidal anti-inflammatory drugs. One of the five reported associated trauma. The average time from onset of symptoms to correct diagnosis was 2.5 years. Juxta-articular osteoid osteoma can cause a small spur that resembles a traction spur on the neck of the talus. Anterior ankle impingement was the most common misdiagnosis. Initial treatments included arthroscopic spur debridement or synovectomy, casting for fracture, and repeated nerve blocks for reflex sympathetic dystrophy. The five patients were cured by en bloc excision of the lesion. In the diagnosis of osteoid osteoma, a history of relief of pain with aspirin is important. Plain radiographs and a bone scan are useful. Fine cut computed tomography scanning or magnetic resonance imaging are the best studies for making a definitive diagnosis. Localization by computed tomography guided needle placement or intraoperative radionuclide scanning are recommended to find the lesion for excision. Intraoperative radiographs of the excised lesion should be used to confirm complete removal.

Recurrent eccrine acrospiroma of the hand

A rare case of a recurrent, benign, eccrine acrospiroma of the hand is described.

Osteonecrosis of the knee following arthroscopic laser meniscectomy

An unusual case of osteonecrosis of the knee following an arthroscopic laser meniscectomy is presented. The unusual presentation of the osteonecrosis and the chronology suggest that the osteonecrosis of the knee resulted from damage to the articular cartilage and subchondral bone at the time of the arthroscopic laser meniscectomy.

Gross, histological, and microvascular anatomy and biomechanical testing of the spring ligament complex

In recent years there has been an increased interest in the treatment of acquired pes planus. The breakdown of the medial longitudinal arch is most often seen at the talonaviculocalcaneal articulation. This suggests a relationship between the ligamentous complex at this articulation and acquired pes planus. This study was undertaken to gain a better understanding of the gross, histologic, and microvascular anatomy, as well as the biomechanics of the ligamentous structures surrounding the talonaviculocalcaneal articulation. Cadaver dissections of 38 fresh-frozen feet were performed. Detailed descriptions of the gross anatomy of the superomedial calcaneonavicular ligament, inferior calcaneonavicular ligament, and the superficial deltoid ligament were recorded. Their relationships to the posterior tibialis tendon and to the bones of the talonaviculocalcaneal articulation are described. The histology and microvascularity of these structures were also studied. Preliminary biomechanical testing was performed. It was found there are two definitive anatomic structures that are commonly called the spring ligament: the superomedial calcaneonavicular ligament (SMCN) and the inferior calcaneonavicular ligament (ICN). The SMCN ligament was found to have histologic properties that suggest significant load bearing. The histology of the ICN ligament suggests a pure tensile load function. The deltoid ligament and the posterior tibialis tendon had direct attachments to the SMCN ligament in all specimens. An articular facet composed of fibrocartilage was found in each SMCN ligament specimen. The microvascular structures showed an avascular articular facet present in the ligament. The biomechanical testing showed that the SMCN ligament and ICN ligament had strength similar to ankle ligaments. This study suggests this "spring ligament complex" has more of a "sling" function for the talar head. It is hoped that the better understanding of this region will add to our understanding of the etiology of pes planus and possible treatment alternatives.

Pathophysiology of immobilization osteoporosis

The reduction of gravity-related forces on the skeleton creates a type of osteoporosis that is unique because its severity is dependent on the mechanical stress bearing function of the skeleton as well as the length of time that the forces are absent or reduced. Bones that bear weight under normal conditions are more affected than bones that normally do not bear weight. The cytokine environment and the cells in the affected bones are altered in time so that stem cells produce fewer new cells and the differentiated cells tend to be less active. These alterations in the local environment of the affected parts appear to resemble those of age- and disease-associated systemic forms of osteoporosis. The osteoporosis produced as a result of the loss of normal activity however, appears to be at least partially reversible through remobilization, strenuous exercise, and--possibly in the future--cytokine therapy.

Anatomy of the plantar plate and its attachments in the lesser metatarsal phalangeal joint

The plantar plate is a rarely seen, yet central structure to the lesser metatarsal phalangeal (MP) joint. Thirty cadaver lesser MP joints were studied to obtain a detailed description of the plate, including its dimensions, connections, and histology. The plate was found to be made of fibrocartilage with fiber orientation which suggests that it withstands tensile loads in line with the plantar fascia as well as the compressive loads from the metatarsal head. The plantar plate was the most substantial distal insertion of the plantar fascia. Impressive plantar plate attachments were noted to the proximal phalanx, the major longitudinal bands of the plantar fascia, and the collateral ligaments. The plate and collateral ligaments formed a substantial soft tissue box connected to the sides of the metatarsal head. From the dissections, it is apparent that malposition of the toe at the MP joint is likely over time to be associated with pathology in both the collateral ligaments and the plate. Because of these attachments and a close association with the flexor tendons to the lesser toe, the plate can be compared with the sesamoid mechanism of the first MP joint.

Lateral epicondylitis: correlation of MR imaging, surgical, and histopathologic findings

PURPOSE

To determine the value of magnetic resonance (MR) imaging in the clinical management of chronic refractory lateral epicondylitis.

MATERIALS AND METHODS

Coronal three-dimensional Fourier transform, multiplanar gradient-recalled-echo, and fat-suppressed sagittal images were obtained in 33 patients. Twenty of these patients underwent surgical débridement and/or primary tendon repair and were included in the correlative study. Surgical and pathologic reports were reviewed to determine the location and gross characteristics of the tissue.

RESULTS

Findings at MR imaging correlated with the surgical findings of primary degeneration of the extensor carpi radialis brevis (n = 20). Histopathologic examination demonstrated neovascularization, disruption of collagen, and mucoid degeneration without inflammation.

CONCLUSION

The use of MR imaging in patients with recalcitrant lateral epicondylitis assists in surgical planning. The definition of tendon degeneration and degree of tear, as depicted on MR images, correlate well with surgical and histologic findings.

Painful os peroneum syndrome: a spectrum of conditions responsible for plantar lateral foot pain

Plantar lateral foot pain may be caused by various entities and the painful os peroneum syndrome (a term coined by the authors) should be included in the differential diagnosis. Painful os peroneum syndrome results from a spectrum of conditions that includes one or more of the following: (1) an acute os peroneum fracture or a diastasis of a multipartite os peroneum, either of which may result in a discontinuity of the peroneus longus tendon; (2) chronic (healing or healed) os peroneum fracture or diastasis of a multipartite os peroneum with callus formation, either of which results in a stenosing peroneus longus tenosynovitis; (3) attrition or partial rupture of the peroneus longus tendon, proximal or distal to the os peroneum; (4) frank rupture of the peroneus longus tendon with discontinuity proximal or distal to the os peroneum; and/or (5) the presence of a gigantic peroneal tubercle on the lateral aspect of the calcaneus which entraps the peroneus longus tendon and/or the os peroneum during tendon excursion. Familiarity with the various clinical and radiographic findings and the spectrum of conditions represented by the painful os peroneum syndrome can prevent prolonged undiagnosed plantar lateral foot pain. Clinical diagnosis of the painful os peroneum syndrome can be facilitated by the single stance heel rise and varus inversion stress test as well as by resisted plantarflexion of the first ray, which can localize tenderness along the distal course of the peroneus longus tendon at the cuboid tunnel.(ABSTRACT TRUNCATED AT 250 WORDS)

Femoral neck bone density. Direct measurement and histomorphometric validation

The purpose of this study was to develop a method for directly measuring bone density of femoral neck sections. Three types of density were measured. Real density equals wet weight divided by the actual volume of bone tissue (real volume). Apparent density equals wet weight divided by the total volume occupied by the bone plus the pore spaces (total sample volume). Ash density equals the ash weight divided by the real volume. Corticocancellous cross-sections of the femoral neck were analyzed for density at two levels: level 1, proximal neck and level 3, distal neck. Density measurements were compared with histomorphometric measurements performed on cross-sections at the midportion of the femoral neck (level 2) and with a clinical radiographic measure of bone density (cortical index 3 cm below the lesser trochanter). No correlation was found between apparent density and either real (r = .12, P = .62) or ash density (r = -.09, P = .72) within a given femoral neck section. There was, however, a strong correlation between real and ash density (r = .93, P = .0001). This was expected because real and ash densities are both reflections of bone mineralization. Apparent density showed better correlation, when comparing level 1 with level 3 sections (r = .76, P = .0001), than did ash (r = .57, P = .01) or real density (r = .55, P = .01). There was no correlation between either real or ash density with any histomorphometric parameter. Apparent density was moderately correlated with total bone area expressed as a percentage of cross-sectional area (r = .66, P = .008). This finding tends to validate the direct measurement of apparent density in that both apparent density and total bone area are measurements of the concentration of bone in space. No significant correlation was found between any of the density measurements and the cortical index at 3 cm. This underscores the necessity for precisely qualifying any definition or discussion of bone quality. The success or failure of hip implants may be at least partially determined by the ability of the bone to withstand the insult of implantation of the prosthesis and to adapt successfully to the new mechanical environment. This study represents an early phase of defining parameters that may have prognostic value in long-term implant fixation.

Soft tissue chondromas: diagnosis and differential diagnosis

The authors evaluated three cases of soft tissue chondromas in patients aged 55, 57, and 78 years. Two of the lesions occurred in the foot and one in the hand. All three patients had long histories (over 1 year) of a palpable mass and all three had roentgenograms showing well-demarcated lobulated soft tissue lesions with both central and peripheral calcifications. Recognition of this rare benign chondroid lesion on imaging studies is significant since it may be misinterpreted as an aggressive lesion or a primary synovial abnormality.

Case report 774. Coincidental parosteal lipoma with osseous excresence and intramuscular lipoma

The parosteal lipoma is a rare but recognizable lesion. The combination of (a) a well-defined, radiolucent, soft-tissue mass that on CT is confirmed to be entirely composed of homogenous mature adipose tissue and (b) an osseous excresence and/or saucerization at the attachment of the soft-tissue mass to the subjacent cortex should be diagnostic. We were unable to find any other case report of a parosteal lipoma coexisting with another lipoma in the same individual.

Cellular repopulation of deep-frozen meniscal autografts: an experimental study in the dog

This study evaluated the cellular repopulation of deep-frozen meniscal autografts. Medial menisci of adult dogs were excised, deep-frozen in liquid nitrogen (-196 degrees C) for 10 min, and orthotopically reimplanted into the joint. Deep-freezing was found to effectively kill all the cells within the meniscus as determined by the absence of Na(2)35SO4 incorporation. Following orthotopic replacement within the knee joint, menisci were repopulated with cells that seemed to originate from the adjacent synovium. These cells migrated over the surface of the meniscus and began to invade the deeper layers of the tissue. However, even after 6 months, the central core of the meniscus remained acellular. While the new cells appeared to modulate into cells that are similar in appearance to meniscal fibrochondrocytes, the exact phenotypic expression of these newly differentiated cells has yet to be determined. Histological alterations, as manifested by a loss of normal orientation of the collagen architecture of the superficial layers of the meniscus; was evident at 6 months and suggests that a remodeling phenomenon may be associated with the cellular repopulation. While biomaterial studies have not been carried out on these specimens, the morphologic alterations observed in the collagen orientation would suggest a possible alteration in the material properties of the repopulated meniscus. The clinical implication of this study is that the structural remodeling associated with the cellular repopulation of deep-frozen meniscal allografts may make the transplanted meniscus more susceptible to injury.

Size of metallic and polyethylene debris particles in failed cemented total hip replacements

Reports of differing failure rates of total hip prostheses made of various metals prompted us to measure the size of metallic and polyethylene particulate debris around failed cemented arthroplasties. We used an isolation method, in which metallic debris was extracted from the tissues, and a non-isolation method of routine preparation for light and electron microscopy. Specimens were taken from 30 cases in which the femoral component was of titanium alloy (10), cobalt-chrome alloy (10), or stainless steel (10). The mean size of metallic particles with the isolation method was 0.8 to 1.0 microns by 1.5 to 1.8 microns. The non-isolation method gave a significantly smaller mean size of 0.3 to 0.4 microns by 0.6 to 0.7 microns. For each technique the particle sizes of the three metals were similar. The mean size of polyethylene particles was 2 to 4 microns by 8 to 13 microns. They were larger in tissue retrieved from failed titanium-alloy implants than from cobalt-chrome and stainless-steel implants. Our results suggest that factors other than the size of the metal particles, such as the constituents of the alloy, and the amount and speed of generation of debris, may be more important in the failure of hip replacements.

The biologic responses to orthopedic implants and their wear debris

The use of artificial materials in the treatment of orthopaedic conditions, most notably arthritis, over the past few decades has been increasing dramatically. Such use makes an understanding of the tissue responses to the various materials necessary to determine their effectiveness and acceptability. This review concentrates on the studies of the biological responses to the materials that are used mainly in joint replacements and fixation of fractures. In-vivo and in-vitro experimental studies of various metals, polymers and ceramics and their constituents are first presented with discussions regarding their clinical importance. Studies of clinically successful implants are then presented to illustrate the expected morphological features of incorporation and acceptance by the host tissues. The local and systemic effects complicating the use of the implanted materials as well as the failure of the implant are then presented.

Longitudinal splitting of the peroneus brevis tendon: an anatomic and histologic study of cadaveric material

Gross and microscopic examinations of 21 split and 10 intact cadaveric peroneus brevis tendons were performed in an effort to determine the pathogenesis of longitudinal splitting of this tendon. The split regions were centered over the posterior margin of the distal fibula and were characterized by splaying of the collagen bundles with accompanying proliferation of blood vessels and fibrovascular connective tissue. Inflammatory infiltrates were not present. Regions of the tendons that were not altered had normal cellularity and orientation of the collagen. The findings of this study suggest that the splitting of the tendon develops through a mechanical mechanism.

Subchondral avascular necrosis: a common cause of arthritis

(1) Subchondral avascular necrosis is an important cause of joint pain and disability and accounts for upwards of 20% of total hip replacements done in our hospital. (2) Early diagnosis may be made with the aid of magnetic resonance imaging and radioactive isotope studies. (3) Although the signs and symptoms are similar to those of osteoarthritis, there are significant differences--namely, (a) a history of sudden onset of pain, present in more than half the patients; (b) a younger age group; (c) a shorter duration of symptoms at time of surgery; (d) clinically the limiting factor is pain rather than actual joint deformity to account for restriction of movement; (e) a high incidence of multiple sites of involvement. (4) The disease is commonly associated with steroid treatment or alcohol abuse. Although many other causes are recognised, they are rare in Western urban practice. (5) Patients with stage I-II subchondral avascular necrosis, especially of the knee, are better treated conservatively. (6) Surgical treatment gives less satisfactory results than the treatment of osteoarthritis by similar modalities.

The tissue diagnosis of metabolic bone disease. Role of histomorphometry

Those aspects of bone histology and histomorphometry that need to be understood by clinicians to put histomorphometry into proper perspective are presented. An increasingly important component of the histologic diagnosis of the metabolic diseases of bone is the quantification of the various histologic features as seen in undecalcified bone biopsies. This article is intended to review some of the histologic features of the metabolic diseases of bone and their corresponding histomorphometric parameters as they are used in diagnosis. The methods of obtaining both direct and derived values as well as the reporting of the results are presented in detail.

Pigmented villonodular synovitis. Diagnosis and differential diagnosis

PVNS is a proliferative disorder that can affect joints, tendons and bursae. Its etiology is unknown. The most widely accepted theories attribute this disorder to a chronic inflammatory response or a benign neoplasm of fibrohistiocytic origin. On gross specimens, the synovial changes are characterized by villous and/or nodular hyperplasia. This disorder occurs most frequently in the third or fourth decades of life and has no sex predilection. As a joint problem, it favors the knee and hip. As a tendon abnormality, it favors the digits. Plain film findings include 1) soft tissue swelling, 2) increased density of the synovium secondary to hemosiderin deposition, 3) multiple subchondral cysts, and 4) extrinsic cortical pressure erosions. Cartilage space narrowing, if present, is gradual and occurs later than the other plain film findings. Arthrography can demonstrate the nodular synovial changes and determine if the process is diffuse or focal. MRI can, in some cases, reveal areas of decreased signal within the hyperplastic synovium reflecting the deposition of hemosiderin. The major roentgen differential diagnoses of articular PVNS include uncalcified synovial chondromatosis, tuberculous arthritis, and hemophilic arthropathy.

Pathologic studies of total joint replacement

Articular endoprostheses are, in effect, foreign bodies designed to re-establish functioning articulations and are, therefore, capable of eliciting a local or systemic response to their presence. This article discusses the body's reactions to foreign bodies in general, and to endoprostheses in particular, and attempts to place those reactions into perspective regarding survival and failure of articular endoprostheses. The effects of size, shape, and composition of the materials used in the prosthetic components, and the mechanical factors acting on them to produce debris, are presented.

Myopathy complicating the acquired immune deficiency syndrome

A case of Acquired Immunodeficiency Syndrome complicated by a severe myopathy is reported. All efforts aimed at documenting an infectious etiology for the myopathy were negative. The relationship of myopathy to AIDS is discussed.

The purely epithelioid malignant peripheral nerve sheath tumor

The purely epithelioid malignant peripheral nerve sheath tumor (PNST) is a rare form of PNT possibly first described by McCormack et al. in 1954. This tumor type is distinguishable from the glandular PNT and PNT with differentiated neuroepithelium (medulloepithelioma and neuroepithelioma) and differs from the ordinary epithelioid PNT because of the absence of a spindle cell component typical of malignant PNSTs. The two examples of purely epithelioid malignant PNT we describe arose in the popliteal fossa from the sciatic and tibial nerves of men with no definite evidence of von Recklinghausen's neurofibromatosis. Both tumors were partly mucinous, and so closely mimicked carcinoma and a few non-neurogenic myxoid sarcomas histologically that their final classification depended upon proof of a neural origin.

Diagnostic pathology in the acquired immunodeficiency syndrome. Surgical pathology and cytology experience with 67 patients

We report the pathologic findings in specimens submitted for histologic and cytologic evaluation from 67 patients with the acquired immunodeficiency syndrome. A wide variety of opportunistic pathogens were identified in 41 patients. Mycobacterium avium-intracellulare evoked only a mild host response: granulomas, if present, were poorly formed. Biopsy specimens showing cytomegalovirus gastroenteritis required sections at multiple levels to demonstrate inclusions. Combined histologic and cytologic evaluation can increase the diagnostic yield in pulmonary and esophageal infections. Kaposi's sarcoma was found in biopsy specimens from 29 patients. Early lesions were often extremely subtle, yet distinct from, benign vascular proliferations in involuted lymph nodes. Malignant lymphoma was diagnosed in ten homosexual men who were suspected of having the acquired immunodeficiency syndrome. The lymphomas were characterized by B-cell origin, a diffuse pattern, frequent extranodal presentations, and an aggressive clinical course with prominent central nervous system involvement.

Cage size and exercise affects infarct size in rat after coronary artery cauterization

Left coronary occlusion in the rat was performed by cornary artery cauterization. A small amount of myocardial damage at the site of occlusion was noted, and myocardial infarction occurred in the distal distribution of the obstructed coronary. The effects of cage size and level of physical activity on estimated infarct size (as measured by creatine kinase depletion) 48 h after occlusion were determined. Isolation in small cages and moderate treadmill exercise resulted in an approximate doubling of the amount of infarction when compared to grouping of rats in large cages. Mild exercise did not increase infarct size. Total urinary catecholamines in normal rats placed in small cages for 48 h were elevated when compared to unconfined rats in larger cages. Cornary artery occlusion by cauterization is an easily performed technique. Cage size and level of activity (and their effects on sympathoadrenal function) are important independent determinations of infarct extent after coronary occlusion in the rat.