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Biomedical subjects

D L Gardner

Publications and source records attributed to D L Gardner.

At least 73 records · Page 4Linked to original sources
PubMed1985

Ultrastructural histochemistry of the surface lamina of normal articular cartilage.

Two collagen-poor, ultramicroscopic layers are described at the surface of canine articular cartilage. They are distinguished by staining with an electron-dense cationic dye, Cupromeronic Blue, in a critical electrolyte concentration technique and by digestion with testicular hyaluronidase. The superficial layer, approximately 50 nm thick, stained at low electrolyte concentrations but failed to stain in conditions specific for sulphated glycosaminoglycans. It was hyaluronidase-resistant and may be either glycoprotein or protein in nature. The deeper layer, 100-400 nm thick, stained positively at electrolyte concentrations specific for sulphated glycosaminoglycans but not in conditions specific for keratan sulphate. It was removed by hyaluronidase digestion. This layer probably represents a chondroitin sulphate-rich proteoglycan. These surface layers may be important in the lubrication of the articular surface and in the permeability and compression resistance of the superficial cartilage zone.

Animals↗
PubMed1985

Low temperature and conventional scanning electron microscopic observations of dog femoral condylar cartilage surface after anterior cruciate ligament division.

The left stifle joints of 16 beagle dogs were subjected to surgical division of the anterior cruciate ligament (ACL). The femoral condyles showed surface alterations and damage after 14 days when examined by low temperature (LTSEM) and conventional scanning electron microscopy (SEM). The first change was an increase in the fibrous texture of the articular cartilage surface. Folds and surface roughening were later recognised. After 112 days deformation and disruption gave way to cracking or fracture of the surface layers. Superficial damage was focal in distribution and accompanied by a decrease in the frequency of tertiary elevations. The affected areas of cartilage increased in frequency and size with time and surgery. The observations obtained from LTSEM, in which the tissue remains fully hydrated during examination, may be caused by alterations in water content and a loss of proteoglycan at the surface, together with changes in cell shape and size. Surface cracks may be the en face appearance of histological fibrillation.

Animals↗
PubMed1985

Alprazolam-induced dyscontrol in borderline personality disorder.

The authors report a significant increase in dyscontrol in patients with borderline personality disorder who were taking alprazolam during a double-blind, placebo-controlled crossover study. They suggest that caution be used in prescribing alprazolam to patients with similar histories.

Adult↗
PubMed1985

Suicidal and parasuicidal behavior in borderline personality disorder.

One of the most perplexing and dangerous aspects of borderline personality disorder is the wide array of suicidal and parasuicidal behaviors. Close phenomenologic evaluation of these behaviors reveals that they can be differentiated into various subcategories. Approaching these behaviors with a biologic perspective may prove helpful in elucidating the underlying etiologies and therapeutic approaches.

Adolescent↗
PubMed1984

The microscopic structure of fibrous articular surfaces: a review.

The present knowledge of the microscopic structure of fibrous articulating surface is reviewed. The influence of dissection, postmortem change, fixation, and dehydration on the microscopic appearances of these surfaces is considered. The results of those studies of surface morphology that investigate intact, supported specimens and that are controlled by surveys of fresh, unfixed, or frozen material are advantageous. New information on the effects of alterations in intermaxillary relationship on the morphology of fibrous articulating surfaces is presented. There is need for further work in this field of research.

Animals↗
PubMed1984

An orally administered microcapsule system for treating chronic renal failure patients.

Ingestible adsorbents for the removal of uremic metabolites are being investigated as adjunctive therapy in the treatment of chronic uremia. In particular, a microcapsule product containing urease and zirconium phosphate (UZP) has been investigated for removing urea. A dog model, simulating chronic uremia, was developed to investigate: (1) the concentration of various nitrogenous metabolites (urea, creatinine, and uric acid) in the GI tract, (2) flux rates of H2O and various nitrogenous metabolites in the GI tract, and (3) the efficacy of the microcapsule product. The results of these perfusion studies suggest that urea and creatinine can be removed from the GI tract via ingestible adsorbents. In addition, the model may be useful in investigating suspect uremic toxins, e.g., guanidinosuccinic acid (GSA). The reduction of blood urea nitrogen levels in the dog model when the animal was fed the microcapsule product was limited by the capacity of the zirconium phosphate to bind ammonium ion. Preliminary clinical studies with the microcapsule product indicate that it may be of potential adjunctive therapy in patients suffering from chronic renal failure.

Administration, Oral↗
PubMed1984

Hyaline articular cartilage dissected by papain: light and scanning electron microscopy and micromechanical studies.

Papain was used to digest the hyaline femoral condylar cartilages of 30 adult Wistar rats. Matrix proteoglycan degradation was assessed by the light microscopy of paraffin sections stained with toluidine blue. The extent of surface structural change was estimated by scanning electron microscopy, and the structural integrity of the hyaline cartilage tested by the controlled impact of a sharp pin. The results demonstrated an early loss of cartilage metachromasia, increasing with time of papain digestion, and an alteration in the shape of the cartilage splits produced mechanically. Accompanying the loss of matrix material was a conspicuous sequence of morphological changes in cartilage surface structure. The results confirm a close relationship between matrix integrity, mechanical properties, and fine structure.

Animals↗
PubMed1984

Low temperature backscattered electron imaging in the study of human tissues.

A scanning electron microscopic technique for the examination of bulk, fresh, hydrated human tissue is described. Samples of fresh tissue are frozen in liquid nitrogen against a mirror-finished copper block and planed in a cryoultramicrotome before transfer to a low temperature scanning electron microscope. After sublimation of water from the specimen surface, the tissue is examined in secondary electron and backscattered electron modes. Adjacent pieces of tissue, and those retrieved after backscattered electron observation, can be readily prepared for and examined by light and by conventional transmission electron microscopy. The method has been tested with multiple blocks taken from 6 cases of human breast carcinoma. In the backscattered electron mode, the infiltrating columns of neoplastic cells can be distinguished from mammary adipose and fibrous tissue. Within a carcinoma, the collagenous stroma, carcinoma cells, and perivascular and perineural infiltrates can be identified. These features have been contrasted with those obtained by light microscopy, by low temperature scanning, and by transmission electron microscopy. This use of backscattered electron imaging for the investigation of unfixed hydrated tissue offers the possibility that the technique could be of considerable value in the microscopy of very small samples in which, because of a need for subsequent biochemical, histochemical, and immunologic investigation, fixation and dehydration are to be avoided.

Adenocarcinoma, Scirrhous↗
PubMed1984

Proteoglycan association with collagen d band in hyaline articular cartilage.

Proteoglycans of canine articular cartilage were labelled for transmission electron microscopy using the cationic copper phthalocyanin dye, cupromeronic blue, in a critical electrolyte concentration method. Much of the proteoglycan appeared to be structurally unrelated to collagen but a small proportion was positioned close to fibrils. On demonstrating the characteristic collagen banding pattern with uranyl acetate and phosphotungstic acid, it was evident that proteoglycan interacted with collagen at the d band.

Animals↗
PubMed1984

Demonstration by X-ray microprobe analysis of relationship between chondrocytes and tertiary surface structure of hyaline articular cartilage.

Blocks of hyaline cartilage from the femoral condyles of five young adult beagles dogs were quench-frozen in nitrogen slush at 63 K. The free cartilage surfaces of blocks from three animals were examined in the secondary electron mode; the remaining specimens were cut by cryoultramicrotone (approximately 188 K) tangential to the surface to expose midzone cartilage which was examined in the backscattered electron mode. A random array of gently convex prominences was apparent at the free cartilage surfaces. When X-ray emissions were recorded from tissue immediately below these elevations, the spectra proved to be similar to those derived from midzone chondrocytes. These spectra revealed high count rates for the X-rays characteristic of P and K. By contrast, in areas of free surface remote from these prominences, and in midzone intercellular matrix, larger count rates for the X-rays characteristic of Na, S. Cl and Ca were detected. The evidence supports the hypothesis that the elevations seen on the non-loaded articular cartilage of disarticulated mammalian synovial joints are the surface representations of superficial chondrocytes.

Animals↗
PubMed1983

Aetiology of rheumatoid arthritis: an attempt to transmit an infective agent from patients with rheumatoid arthritis to baboons.

Thirty baboons were injected intravenously and intra-articularly with material from the joints of 19 patients with active rheumatoid arthritis or with control material. Fifteen of the 30 animals received synovial fluid cells or synovial membrane cells from 3 patients with seronegative arthritis. Ten animals received pooled cells from a total of 16 cases of seropositive arthritis. Five animals were given nonrheumatoid cells. No signs of arthritis were recognised in the 27 surviving animals during 3 years of observation. No significant biochemical, haematological, or serological changes occurred during this period, and no gross or microscopic evidence of synovial or systemic disease was found post mortem.

Adult↗
PubMed1983

Synovial response of Papio cynocephalus to exogenous antigen: histological and immunoperoxidase observations.

Acute experimental synovitis was produced by intra-articular challenge of 3 baboons (Papio cynocephalus) sensitised with ovalbumin. Haemagglutination tests revealed high titres of circulating antiovalbumin antibody. Measurements were made of articular diameter, circumference, and temperature before the animals were killed on days 1, 5, and 20. The sterile synovitis was investigated microscopically and by immunoperoxidase methods. IgG, IgM, IgA, C3, and fibrin were identified within the synovial membranes which were extensively infiltrated with plasmacytes and other mononuclear cells. It was concluded that the baboon can respond to exogenous antigen histologically in a manner analogous to that of nonprimates. Some features of the response recall those of the synovitis of active human rheumatoid disease.

Animals↗
PubMed1983

An investigation by transmission electron microscopy of freeze replicas of dog articular cartilage surfaces: the fibre-rich surface structure.

Femoral condylar cartilage blocks from the disarticulated stifle joints of five inbred beagle dogs were rapidly frozen. Single stage platinum and carbon replicas were prepared at 78 K from the unfixed, hydrated frozen material. Transmission electron microscopic investigations of the replicas were then made. Two different forms of fine cartilage surface structure were suggested by the low temperature replicas. The first, amorphous and with few fibres, was thought to represent the normal, superficial lamina obscurans. The second displayed many delicate parallel arrays of collagen fibrils with a periodic structure of 68-71 nm. Between these arrays were gently convex smooth-surfaced elevations, 150-500 nm in diameter, and therefore two orders of magnitude smaller than the tertiary surface undulations previously identified by light microscopy and by scanning electron microscopy. It is suggested that the 150-500 nm elevations seen at the replicated surface may be expanded proteoglycans, restrained laterally and deeply, less restrained superficially because of the loss, during preparation, of the lamina obscurans. Other hemispherical, replicated surface deposits 400-1700 nm in diameter are believed to be lipid.

Animals↗
PubMed1983

Ultrastructural changes in dog femoral condylar cartilage following anterior cruciate ligament section.

Canine femoral condylar cartilage from stifle joints subjected to surgical division of the anterior cruciate ligament showed conspicuous, widespread alterations in chondrocyte morphology and matrix organisation when compared by transmission electron microscopy with cartilage from sham-operated and non-operated joints. Chondrocyte changes were of a kind associated with increased synthesis of matrix components; zone I cells lost their flattened shape and became rounded, cells in zones I and II developed an extensive endoplasmic reticulum, occurred in pairs more often than usual and were situated in enlarged electron-lucent lacunae. Associated with altered chondrocyte function and increased hydration, the matrix became increasingly disorganised; collagen fibrils were widely separated, disorientated and of small diameter. It is postulated that the disorder is primarily one of inappropriate cell function.

Animals↗
PubMed1982

The postnatal development of the temporomandibular joint of the common marmoset (Callithrix jacchus).

The temporomandibular joints (TMJ) of 55 male and 50 female common marmosets (Callithrix jacchus) with an age range of 1 day- to < 12-yr-old have been studied to extend the knowledge on the craniomandibular articulation of this primate. Details of changes in the bone structure, gross and functional anatomy, and histologic appearance of the marmoset TMJ during the neonatal period, infancy, childhood, adolescence, and adulthood are compared with those which occur in the TMJ of man. It is concluded that further investigations on the structure and function of the marmoset TMJ and jaws may establish this nonhuman primate as a valuable analog for TMJ research in man.

Aging↗