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Biomedical subjects

T B Kardos

Publications and source records attributed to T B Kardos.

29 records · Page 2Linked to original sources
PubMed1989

Histological evaluation of the effect of a miniature carbon dioxide laser on oral mucosa.

Carbon dioxide lasers emit infra-red radiation at a wavelength of 10600 nm, making them suitable for tissue vaporisation, incision and vessel coagulation. A miniature CO2 laser (length 24 cm), with an output of 4 Watts focused on to a spot of 0.2 mm diameter at a distance of 2.5 mm from the nozzle tip, has been developed. This hand-held, water-cooled device operates off a 12 V D.C. source and provides good access to most areas of the mouth. In order to evaluate the use of the miniature laser, a series of lesions were produced on the lateral margins of sheep's tongues, and histological examination of tissues carried out immediately after treatment and at 1 h; 1, 2, 4, 7, 14, 21, and 28 day intervals. Wounds showed clean cut margins with even removal of epithelium and superficial connective tissue. Damage appeared to be restricted to a 100 microns deep zone in the lamina propria. Epithelial regeneration had commenced at between 2 and 4 days, and re-covered the surface by 14 days. A residue of chronic inflammatory cells was present within the stroma at 21 days, but this had resolved by 28 days. The miniature carbon dioxide laser is effective in vaporising oral mucosa and also achieving haemostasis by vessel coagulation; its manoeuvrability and relatively low cost warrant further clinical evaluation for the treatment of mucosal lesions, such as leukoplakia.

Animals↗
PubMed1989

Scanning electron microscopy of trypsin-treated enamel from fluorosed rat molars.

Fluoride-induced pitting and porosity of teeth have long been observed, but little progress has been made in determining their origin. We have observed, in the trypsin-treated surfaces of enamel, pits that disappear on completion of maturation, following the removal of the protein matrix and full mineralization. Since these pits were considered to be similar to those seen in fluorotic teeth, this scanning electron microscope (SEM) study was undertaken to determine the effect of fluoride on these transient developmental pits during enamel matrix maturation. A group of 20 eight-day-old rats was given daily intraperitoneal injections of NaF (20 mg/kg [9 mg F-/kg] body weight) for five days. Twenty control animals received intraperitoneal injections of isotonic saline. Maxillary and mandibular molars were dissected from the 13-day-old animals, washed in HEPES buffered (Ca2+/Mg2+) free basal medium, Eagle's (BME), incubated in 3% trypsin/BME for 5-10 min at room temperature, then indirectly sonicated in BME for 2-4 min. Clean crowns were fixed in 2.5% glutaraldehyde for three hr, dehydrated, critical-point-dried, and sputter-coated for SEM. Pits in the surfaces of developing enamel were observed in all groups. In control teeth, the pitting was restricted to the cervical margin, whereas in teeth from the fluoride-treated animals, pits were observed on some cuspal surfaces in addition to the cervical margin. These results confirmed that pits in trypsin-treated surfaces of developing enamel are a transient developmental event and showed that, in the presence of a high dose of fluoride, the maturation of enamel is modified with retention of the pits.

Animals↗
PubMed1986

Mandibular vascular leiomyoma.

A 54-year-old man had a symptomless swelling on the buccal aspect of the right mandibular molar area, this was associated with a multilocular radiolucency. Histologic and ultrastructural examination of the lesion revealed a vascular leiomyoma. This is only the fourth intrabony leiomyoma of the jaws to be reported.

Diagnosis, Differential↗
PubMed1981

Calmodulin-like activity in a mineralising tissue: the rat molar tooth germ.

Calmodulin, a calcium binding protein, has been implicated in the regulation of many calcium-dependent biological processes. Since calcium has an important role in hard tissue genesis, both at intra- and extracellular levels, we anticipate that calcium binding proteins may modulate this process. The present study investigated a mineralising tissue, the rat molar tooth germ, to determine the presence of calmodulin-like activity. A heat-treated cell-free extract of tooth germs provided enhancement of Ca2+-dependent Mg2+-ATPase and 3':5'-nucleotide phosphodiesterase activity. No enhancement occurred in the absence of calcium or in the presence of trifluoperazine. SDS-polyacrylamide gel electrophoresis of this extract revealed a protein band of approximately 18,000 mol. wt. These findings indicate the presence of calmodulin-like activity in rat molar tooth germs and support the proposal that calcium and calcium binding proteins, in particular calmodulin, have a major regulatory role in the biology of mineralising tissues.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1981

Intracellular mineralization of Bacterionema matruchotii.

Intracellular calcium phosphate mineral formation in Bacterionema matruchotii has been examined relative to two established points: the product of calcium and phosphorus levels at which spontaneous precipitation occurs (Ca x P), 50 (mg%)2, and the product at which calcium hydroxyapatite itself induces crystal growth, 35 (mg%) 2. The extent of intracellular mineralization in the defined calcifying medium was determined analytically after washing the cells. Electron micrographs of B. matruchotii cells revealed needlelike crystals of mineral, typical of calcium hydroxyapatite. Bacterionema matruchotii was found to be an efficient nucleator and can bring about the formation of solid phase at a Ca x P product as low as 35 (mg%)2.

Actinomycetaceae↗
PubMed1981

Rapid dissection of rodent molar-tooth germs.

A rapid rate of isolation of molar-tooth germs from rodents aged from 19 embryonic days to 7 days postnatal can be achieved. The procedure is of direct application to biochemical studies of odontogenesis where relatively large amounts of tissue are often required. The quality of dissection, assessed by morphological and organ culture criteria, extends the application of this procedure to general use in the isolation of molar-tooth germs from rodents.

Animals↗
PubMed1980

A new periodontal membrane biology based upon thixotropic concepts.

The biology of the periodontal membrane is not completely understood, and tissue changes associated with orthodontic tooth movement are assumed to be the result of a recoverable pathologic process. The response of this tissue to dynamic loading may, however, be explained by changes in viscosity of the collagenous matrix.

Biology↗
PubMed1975

The immunogenicity of tooth allografts in rats.

Orthotopic and heterotopic tooth allografts stimulated the production of alloantibodies in rats incompatible at the major histocompatibility locus. The immunogenicity of whole tooth grafts was slightly diminished but not eliminated by sealing the pulp cavity prior to grafting. Suspensions of dentine in saline elicited alloantibody formation on i.p. injection into allogeneic hosts. Orthotopic tooth allografts, but not heterotopic grafts, were as effective as skin allografts at stimulating second set rejection of challenging skin grafts. Orthotopic tooth allografts were indistinguishable from syngeneic grafts on histological examination over the period 1-6 weeks after grafting. The occurrence of alloantibody formation after tooth grafting was capricious, and this, combined with the histological difficulty of distinguishing syngeneic from allogeneic grafts, and also the differing capacity of orthotopic and heterotopic tooth allografts to provoke accelerated skin grafts rejection, probably accounts for some of the differences of opinion expressed previously on the immunogenicity of grafted teeth.

Animals↗