Tissue Erosion Research Articles

Parallel clinical and behavioural studies of adjuvant-induced arthritis in the rat: Possible relationship with ‘chronic pain’

The course of adjuvant-induced arthritis was followed, over an 11-week postinoculation period, in Sprague-Dawley rats, using both clinical and behavioural methods of study. Clinical observations included body weight, diameters of radiocarpal and tibiotarsal joints and radiological analysis of forepaws, hindpaws and vertebrae. Behavioural observations included those of spontaneous behaviour - mobility, exploring, rearing, penis licking and scratching - and of pain-related tests - the foot-bend procedure and Randall-Selitto test. In general, the time course of the disease could be divided into 4 stages, viz. a preclinical, an acute, a postacute and a recovery stage. The preclinical stage (first week) was characterized by discrete radiological lesions of the forepaws and a slight increase in the threshold for struggle triggered by foot pressure, but, above all, by no change in the other parameters. The acute stage (weeks 2–4) was clearly defined by a pause in body weight gain and by dramatic behavioural changes: a lack of mobility and exploring behaviour, a profound increase in scratching behaviour and signs of hyperalgesia. During this period, hindpaw and forepaw joint diameters increased dramatically. The behavioural modifications peaked at the same time (week 4) as there was an acceleration in the radiological abnormalities (soft tissue swelling, demineralization and erosion of bone extremities and joint space narrowing) which had begun during week 3. During the postacute stage (weeks 5–8), body weight and behavioural reactions began to return towards control values, but joint diameters and radiological scores either continued to increase or remained constant. During the recovery stage (weeks 9–11), behavioural scores and body weight returned to control values while the mean joint diameters remained constant and there was a slight decrease in the radiological scores. In spite of the complexity of the model used in these studies, it appeared quite clear that the acute phase of the disease was characterized by the onset of clinical symptoms and dramatic changes in behaviour, all of which could be related to the occurrence of pain; signs of pain were still present, albeit weaker, in the postacute phase. Such observations, taken together, help to validate adjuvant arthritis as an experimental model of chronic pain in Sprague-Dawley rats.

Softenable, Shape-Memory Thermoplastic for Use in Biomedical Devices

AbstractMany implantable biomedical devices could benefit from a material with a strongly temperature-dependent modulus. Catheters made from such a material could be inserted as a stiff plastic, and upon reaching body temperature, would soften dramatically to minimize erosion of adjacent tissue. Sutures could be stiff during placement in an incision, heated slightly to form a shape to hold the suture in place, and then cooled. A new family of materials known as softenable, shape-memory thermoplastics have a distinct and adjustable thermal transition that produces a dramatic change in modulus at a predetermined temperature (range)

An Ultrastructural Study of Corneal Incisions Induced by an Excimer Laser at 193 nm

Far ultraviolet light (193 nm) produced by an excimer laser has been used to produce a variety of incisions in the corneas of anaesthetised rabbits. Tissue was lost from the site of irradiation but the nature of the underlying molecular interactions responsible for such tissue erosion remain obscure. Ultrastructural analysis of the walls of the ablated areas show damage to the adjacent structures to be confined to a zone 60 to 200 nm in width. These dimensions could either be attributed to photochemical processes in which high energy photons directly break organic molecular bond, or to thermal reactions which result in limited heat flow and damage confined to the absorption depth at 193 nm of less than 1 μm. In non-penetrating incisions that reached within 40 μm of Descemet's membrane, endothelial cells were lost beneath the line of the irradiation. This spalling of cells seemed to be generated by shock or acoustic waves.

Development of a One-Piece Reentrant Cannula for the Proximal Duodenum of Dairy Cows

A one-piece cannula was developed for reentry or spot collection of duodenal digesta in dairy cows. Progession through three cannula designs is described. Exteriorizing cannulae between the tenth and eleventh ribs produced stable preparations although ribs were deformed. A simple one-piece T cannula was suitable for spot sampling, but digesta blockage prevented its use for reentry collections. A double entry T cannula was unsuitable for reentry collections because of digesta blockages and inability to secure diversion gates in the cannula. A Y-shaped cannula allowed blockage-free reentry collections and easy spot sampling. Diversion gate design provided for a snug fit, and dualphase digesta marker recovery studies and necropsy findings suggested complete diversion in two of three cows. Post-mortem observations of rib distortion and intestinal tissue erosion from between the cannula and abdominal wall suggest inclusion of an inner restraining collar for future preparations. Several other modifications are discussed.

Oral tissue alterations associated with the use of smokeless tobacco by teen-agers: Part I. Clinical findings

The use of smokeless tobacco appears to be finding its way onto middle school, high school, and college campuses as a socially acceptable and popular habit. Numerous reports in the literature have described the oral changes that appear to be associated with the use of smokeless tobacco in adults. Such information is unavailable for the lower age groups. A study was therefore undertaken to determine the prevalence and frequency of oral hard- and soft-tissue alterations associated with the use of smokeless tobacco in a teen-age population. High school students in grades 9 to 12 were evaluated on a random basis. From a total sample of 1,119 students, 117 users of smokeless tobacco were identified. Four distinct lesions associated with smokeless tobacco use were identified clinically: (1) hyperkeratotic or erythroplakic lesions of the oral mucosa, (2) gingival or periodontal inflammation, (3) a combination of oral mucosal lesions and periodontal inflammation, and (4) cervical erosion of the teeth. Among the smokeless tobacco users. 113 were boys and 4 were girls. Fifty-seven (48.7 percent) of the users had soft-tissue lesions and/or periodontal inflammation or erosion of dental hard tissues. Ninety-nine of the 117 users were Caucasian, 6 were Hispanic, 1 was black, 1 was Asian, 1 was an American Indian, and 6 failed to identify an ethnic origin. Use ranged from one to twenty “dips” per day, with an average time per dip of 30 minutes. Most users had been dipping for an average of 2 years, and twelve different tobacco brands were identified.

Preclinical and clinical evaluation of topical acid products for skin tumors.

Distinct differences between topical acid preparations can be detected by simple preclinical and clinical pharmacologic models designed to evaluate potential utility in the treatment of superficial skin tumors. The models distinguish a tissue-dissolving (ulcerating) effect from a tissue-fixation (mummifying) effect, as reflected by a distinct and lasting discoloration of hair in vitro or the skin surface in vivo. Double-blind clinical comparison of the response to different preparations of matched pairs of small superficial skin tumors in 33 subjects demonstrated for greater utility for nitric acid preparations of appropriate strength (6 to 7N), with added oxidizable organic acids, over the mineral acid alone. The nitrate reduction products generated in such preparations markedly speed up discoloration in the models and apparently contribute to the improved clinical utility of the topical treatment by enhancing the speed and intensity of tissue fixation, but not tissue erosion. The architecture of lesions eradicated by such mixtures is generally adequately preserved for histologic diagnosis of the extruded tissue.

An unusual presentation of a ring injury

A case of chronic erosion of the soft tissues and bone of the proximal phalanx of the ring finger in a 62-year-old woman is presented. The patient's rings had eroded the skin, nerves, and tendons of the finger as well as the palmar aspect of the proximal phalanx; however, circulation was adequate. When the rings were removed, there was no improvement in sensibility or range of motion, but this was not bothersome to the patient.

Complications Associated with Use of Tantalum-Mesh — Covered Implants

In 1948, ophthalmologists started implanting plastic spheres partially covered with tantalum mesh (eg, the Valley Forge Implant) in anophthalmic sockets. Numerous patients have developed complications ten to 15 years after surgery: pain (“pinching” or “deep”), headache, heavy mucopurulent discharge and diffuse conjunctival inflammation, migration of the implant, thinning or erosion of tissues covering the implant (extrusion), and inability to wear an artificial eye. Management includes refabrication of the artificial eye and replacement of the implant with a dermis-fat graft or a silicone ball plus scleral graft. Tantalum-mesh—covered orbital implants should probably not be used.

A NEW CHIN IMPLANT FOR MICROGENIA

We describe our experiences with a new silicone bag-gel chin implant, developed in two phases over a 4-year period. Fifty patients received the Phase I implant, and such complications as internal and external soft tissue erosion, indentation, slippage, asymmetry, infection, andd late bone resorption (two cases) were seen. Subsequently 28 patients received the Phase II implant, and have been followed up to one year. So far, the only complication has been asymmetry in one case.

Macrophage-mediated cytotoxicity: its possible role in rheumatoid arthritis.

The association of macrophages with destructive processes in transplantation and tumoral, bacterial, and protozoan immunity illustrates their versatility in different situations. Their participation in inflammatory responses, including graft rejection and rheumatoid arthritis, would guarantee focal areas of high concentrations of hydrolytic enzymes and other macrophage products. That erosion of synovial tissue occurs in the presence of enzymes known to be associated with macrophages suggests that the large numbers of infiltrating macrophages and destruction of synovial tissue may be related.

Rheumatoid arthritis of the wrist: why the ulnar styloid?

Involvement of the distal ulna in rheumatoid arthritis results from abnormalities in surrounding anatomic structures. Synovial inflammation in the prestyloid recess, a diverticulum of the radiocarpal joint which is intimate with the styloid process, produces erosions of the styloid tip. Similar inflammation in the inferior radio-ulnar compartment, in conjunction with altered mechanical factors, produces scalloping of adjacent surfaces of the distal radius and ulna. Involvement of the synovium within the sheath of the extensor carpi ulnaris tendon accounts for early soft tissue prominence and erosion proximal to the tip of the ulnar styloid. Focal periostitis may result from a healing attempt by the eroded bone.

Genetic inhibition of mesenchymal cell death and the development of form and skeletal pattern in the limbs oftalpid3(ta3) mutant chick embryos

ABSTRACTVital staining reveals that in homozygous (ta3/ta3) talpid3 embryos, the areas of mesen-chymal cell death which occur regularly in normal limb development are absent or reduced.The necrotic locus in the central mesenchyme (the ‘opaque patch’) which in the normal chick limb reaches maximum development at stages 24 and 25 is absent or much reduced in talpid3 fore-and hindlimb-buds. Autoradiographic studies, following application of a 2 h pulse of 40 μCi of35SO4 to the vitelline circulation, show that normal tibia and fibula incorporate 35SO4 into chondroitin sulphate at stage 24 and more strongly at stage 26 during the process of chondrogenesis. The mesenchyme in the opaque patch region of normal limbs ceases to incorporate 35SO4 into chondroitin sulphate at stage 24. Talpid3 mesenchyme cells in the equivalent position at stages 24 and 26 continue to incorporate 35SO4, remain viable and become chondrogenic. It is suggested that absence or reduction of this central necrotic locus in talpid3 is causally related to the fusion of radius/ulna and (in some cases) of tibia/fibula characteristic of the later stages (28–35) of talpid3 limb development. This evidence supports the hypothesis that cell death in the opaque patch plays a morphogenetic role in separation of radius/ulna and tibia/fibula.The digital plate of stage 32 normal limbs is characterized by massive necrosis of the interdigital tissue. In talpid3 forelimbs of stages 30–35 interdigital necrosis is absent, and there is no regression of the tissue between the digits (‘soft tissue syndactyly’). In talpid3 hindlimbs of stage 30–35 interdigital necrosis is either absent or much reduced, and there is little or no erosion of the soft tissue between the digits. This evidence supports the hypothesis that the morphogenetic role of interdigital cell death is in causing separation of the digits through shaping and remodelling the contours of the digital plate.

IV. Joint erosion in rheumatoid arthritis.

AbstractIn rheumatoid arthritis, destruction of the collagenous structures that comprise the joint is associated with proliferation of synovial lining cells. Erosion of cartilage, bone, and soft connective tissue occurs predominantly in areas adjacent to these cells and the collagen of these tissues is susceptible to degradation at neutral pH by collagenase from the proliferating cells. The collagen fragments thus solubilized are further broken down by other proteases. Cartilage collagen is attacked more slowly by synovial collagenase than are soft tissue collagens, presumably due to its particular primary structure and post‐translational modifications of this primary structure. Proteoglycans are degraded probably by proteolytic attack on the protein backbone. The inorganic mineral phase of bone prevents collagenolytic attack on bone matrix; mechanisms of mineral dissolution may include a local decrease in pH and release of substances such as prostaglandins from the inflammatory cells. The degradation of each structural component results in specific alterations in form and function of the joint.

Radiographic evaluation of the prevertebral space.

AbstractThe prevertebral space as seen on the lateral soft tissue X‐ray is discussed. Variations of normal in the child and adult are reviewed. Normal anatomy may give a false impression of pathology such as air in the ear canal, lung apices, and cervical esophagus. Overlying shadows of other structures, namely, the ear, styloid, stylohyoid ligament, calcified anterior arch of the atlas in a child, calcification in the cricoid signet and cartilago triticea also may be confusing. Physiological changes with crying or swallowing in the child at times appear as pathology. The primary pathological changes seen on X‐ray are air in the tissue spaces, foreign bodies, tumor formation, erosion or proliferation of bone, fractures, deformities of the spine such as reversal of the normal curvature or slippage of the vertebrae, and displacement of the fat line. It must be kept in mind that X‐rays are only one additional tool for making a diagnosis and cannot be substituted for a thorough history and physical examination.The normal with many of its variations as well as a considerable number of pathological changes are illustrated.

Hemoperitoneum from erosion of ectopic endometrial tissue.

Hemoperitoneum from erosion of ectopic endometrial tissue.

Inverted papilloma of the nasal cavity.

ALTHOUGH the inverted papilloma of the nasal cavity and paranasal sinuses is a neoplasm that is histologically benign by the usual pathologic definition, experience with a number of patients over a period of time has proved it deserves a classification of clinically malignant. Even though this is not a rare condition and has received detailed study, a wide recognition of the frequency of this tumor and its destructive clinical course has not been evident. Bone erosion and invasion of adjacent soft tissue frequently occur because persistence or recurrence has followed an inadequate operation for a tumor too generally accepted as an inflammatory or fleshy polyp with metaplasia. Where repeated removal of recurrent polypoid tissue permits a review of the previous histological material, the characteristic features of inverted papilloma have been found to be present in the earlier specimens. It is the rapid recurrence of the nasal tumors and the accompanying

Ovarian pregnancy: With a report of three cases

Three examples of ovarian pregnancy are presented, each of which fulfills the criteria necessary for making such a diagnosis. From the clinical standpoint, one of them presented a diagnostic problem, while the other two presented findings which readily permitted a diagnosis of ectopic pregnancy, and one was an extremely acute case, with extensive intraperitoneal hemorrhage. Cases 2 and 3 represent an unusually early rupture. Study of the specimens revealed in two of them well-developed corpora lutea adjacent to the pregnancy, the so-called juxtafollicular implantation, but whether this was preceded by fertilization in the actual follicle or on the surface of the ovary, it is, of course, impossible to say at the present time. The well-developed and intact corpora lutea so close to the pregnancy rather suggest fertilization in the follicle, followed by rapid invasion of the underlying ovarian stroma. In none of the specimens was any decidual reaction noted.The fate of the ovum in ovarian pregnancy is comparable to that which takes place in other forms of extrauterine pregnancy; namely, development for a period of time, with associated erosion of the adjacent tissues and eventual rupture, with sometimes slight and sometimes severe symptoms. While we have not encountered an example, it is interesting to note that a higher percentage of ovarian pregnancies proceed to term than is the case with tubal pregnancy, this being no doubt due to the more resistant type of tissue in which the pregnancy is embedded.

CEREBRAL ARTERIOSCLEROSIS

My object in this paper is to show that sclerotic blood vessels in the brain at times so press on and actually excavate the adjacent parenchymatous tissue that clinical pictures are produced resembling those of focal lesions. In the course of study of the pathologic changes in many cases of cerebral arteriosclerosis my colleagues and I were struck by the fact that in a small number the blood vessels acted as minute expansile lesions. We saw in some instances actual erosion of brain tissue, so that eventually a small groove was formed by the sclerotic, tortuous and frequently enlarged blood vessel at the expense of the functioning structure of the brain. This condition has not been entirely overlooked in the literature, since reference to it has been made particularly in conjunction with pressure on cranial nerves. Pappenheim,1in 1926, claimed that trigeminal neuralgia can be caused by pressure of