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Biomedical subjects

P Person

Publications and source records attributed to P Person.

At least 19 recordsLinked to original sources
PubMed1992

Alkaline phosphatase and peptidase levels in invertebrate cartilage.

Cartilage is encountered in the skeletons of many advanced invertebrates, yet it never calcifies or is replaced by bone. In an attempt to account for the absence of bone in invertebrates, we tested a hypothesis proposing that absence or inadequate quantities of several enzymes associated with vertebrate osteogenesis may underlie the failure of the invertebrates to evolve bone. The enzymes examined were alkaline phosphatase, alanyl beta-naphthylamidase, and neutral protease. Their activities were measured in the gill cartilage of the Atlantic horseshoe crab, Limulus polyphemus, and the odontophore cartilage of the marine whelk, Busycon canaliculatum. Animals were collected from the Cape Cod area. Samples of cartilage of Limulus perichondrium, various non-skeletal tissues, and neonatal rat calvaria, the latter as a reference standard, were homogenized in 0.1 M phosphate buffer (pH 7.1) and analyzed for protein content and the above-mentioned enzyme activities. Alkaline phosphatase specific activity was readily detected in most tissues except the invertebrate cartilage specimens in which it was present only at near-trace levels. Naphthylamidase and protease activities were present in all tissues. In a single experiment, higher phosphatase values were recorded for Limulus cartilage retaining perichondrium, but in a subsequent trial assaying cartilage retaining perichondrium, denuded cartilage, and isolated perichondrium separately, it was demonstrated that phosphatase activity resided primarily within the perichondrium. Exposure of thick cryostat sections to p-nitrophenyl phosphate confirmed the suspicion that alkaline phosphatase activity was present principally in the perichondrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1992

Neuralgia-inducing cavitational osteonecrosis (NICO). Osteomyelitis in 224 jawbone samples from patients with facial neuralgia.

A somewhat obscure etiologic theory for facial neuralgias presumes a low-grade osteomyelitis of the jaws that produces neural degeneration with subsequent production of inappropriate pain signals. Animal investigations and treatment successes with human patients based on this theory lend it credence. The present study examined 224 tissue samples removed from alveolar bone cavities in 135 patients with trigeminal neuralgia or atypical facial neuralgia. All tissue samples demonstrated clear evidence of chronic intraosseous inflammation. The most common microscopic features included dense marrow fibrosis or "scar" formation, a sprinkling of lymphocytes in a relative absence of other inflammatory cells (especially histiocytes), and smudged, nonresorbing necrotic bone flakes. Very little healing or new bone formation was visible. These lesions were able to burrow several centimeters to initiate distant cavities. The present preliminary investigation cannot prove etiology, but the presence of intraosseous inflammation in every single jawbone specimen in these patients and certain clinical and treatment aspects of these lesions (to be reported later) has led the authors to recommend the term neuralgia-inducing cavitational osteonecrosis or NICO for these lesions.

Adult↗
PubMed1992

Preserving avulsed teeth for replantation.

We performed a retrospective study of 34 replanted avulsed teeth placed in an EPTS before replantation. Even when extraoral time was 120 minutes or more, 91 percent of the teeth showed excellent or moderate success for follow-up periods ranging from three to 30 months. We think that the success of a replanted avulsed tooth is increased by use of a prefabricated tooth preserving and protecting system as described.

Follow-Up Studies↗
PubMed1992

A comparative clinical study of the safety and efficacy of three toothbrushes.

This single (examiner) blind, randomized, 4-week study compared the safety and efficacy of a new electric toothbrush (experimental) regarding plaque removal and reducing gingivitis with two other brushes, an electric brush (control electric) and a manual toothbrush (control hand). Ninety-six subjects with 1) a minimum of 15 suitable teeth in acceptable occlusion; 2) a minimum gingivitis score of 0.9; and 3) a minimum plaque score of 1.8 were entered into the study. The subjects were randomly assigned to one of 3 groups: a control hand group (31 subjects), an experimental group (32 subjects), and a control electric group (33 subjects). Device use instructions were given according to the manufacturer's recommendations. Two examiners separately determined either gingival scores or plaque scores at baseline and 4 weeks. In regard to gingivitis, use of all 3 brushes for the study period showed statistically significant improvements in gingivitis scores (P values less than 0.01) within each of the 3 groups. Between group analyses of covariance showed that of the 3 groups, the control hand group improvement was better than both the experimental and the control electric groups (P less than 0.05). When interproximal gingivitis scores were analyzed separately, similar improvements were noted. Regarding effectiveness of plaque removal during a single brushing event at the initial and final visits, each of the 3 brushes was effective in reducing plaque for every tooth surface scored (P values less than 0.01). However, between group analyses of covariances showed that the experimental group was better than the other two (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Effect upon plaque formation and gingivitis of a triclosan/copolymer/fluoride dentifrice: a 6-month clinical study.

A total of 159 adult male and female subjects between 18 and 63 years of age, were entered into a 6-month, double-blind clinical study to assess the effects of a dentifrice containing 0.3% triclosan and 2% of a copolymer of methoxyethylene and maleic acid on supragingival plaque formation and gingivitis, as compared to a placebo dentifrice. Both the triclosan and placebo dentifrices contained 0.243% sodium fluoride in a silica base. The subjects had to demonstrate at least mild gingivitis (modified Loe-Silness score > or = 1.0), be free of advanced periodontal disease, have a modified Quigley-Hein Plaque Index score of at least 1.5 and have a minimum of 20 natural, uncrowned teeth. The subjects were stratified into two balanced groups according to baseline plaque and gingivitis scores. At zero time or baseline, all subjects received a complete and thorough oral prophylaxis and were assigned to the use of either the placebo dentifrice or the triclosan/copolymer dentifrice for the next 6 months. Subjects were evaluated for gingivitis and supragingival plaque formation after 3 and 6 months product use. After 3 months, when compared to the placebo dentifrice, the triclosan/copolymer dentifrice provided the following statistically significant reductions (at 99% confidence levels): (1) a 10.0% reduction in supragingival plaque formation; (2) a 20.8% reduction in plaque formation on tooth surfaces with highest baseline plaque scores; (3) a 21.9% reduction in gingivitis, and (4) 30.5% less sites with severe gingivitis, i.e. gingival bleeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Delayed carpal ossification in Notophthalmus viridescens Efts: Relation to the progress of mesopodial completion in newt forelimb regenerates.

The persistence of cartilage in the adult newt (Notophthalmus viridescens) forelimb skeletal regenerate has recently been reported by Libbon et al. It is particularly evident in the carpal group, which remains cartilaginous for at least 9 months while all other regrown skeletal parts are either ossified or ossifying. The present investigation was undertaken to determine whether delayed ossification in the adult regenerate recapitulates a pattern evident during the development of the forelimb of the red eft (N. viridenscens' immature terrestrial phase). Right upper limbs of 20 efts were examined at low magnification to establish carpal composition and organization. Among five efts of the smallest size (26.54 plus or minus 2.20 mm snout-to-vent length), and displaying bright orange dorsal skin coloration, all carpal rudiments were cartilaginous. Eleven efts, intermediate in length (33.88 plus or minus 0.81 mm), displaying orange-green coloration, all carpals had ossified. These observations demonstrate that during adult newt forelimb regeneration, the failure of the carpal elements to begin ossification in synchrony with other regrown skeletal parts duplicates a similar schedule of delayed mesopodial ossification which is evident during the development of the red eft's forelimb.

Animals↗
PubMed1986

Plaque reduction unaccompanied by gingivitis reduction.

The effects of brushing with three different dentifrices on plaque accumulation and gingival inflammation were studied in 83 subjects. The Turesky modification of the Quigley-Hein plaque index and a modified Löe-Silness gingivitis index were employed. Index scores were obtained in a randomized, double-blind study design, at 0 (baseline), 3-, 6-, and 9-week intervals. ANOVA analyses of results showed no significant differences between any of the three dentifrices used with respect to observed effects. Of interest, however, was the observation that with all three dentifrices reductions in plaque accumulations occurred, at 1% and 5% significance levels, without a corresponding commensurate improvement in the inflammatory status of the associated gingivae (using paired sample t-test analyses). The above results and relevant literature are discussed in support of the thesis that at times, for reasons as yet inexplicable, plaque and gingival inflammation may not be causally related in the manner so commonly observed.

Adjuvants, Pharmaceutic↗
PubMed1984

Further observations on dental parameters of trigeminal and atypical facial neuralgias.

One hundred thirty-one patients with primary trigeminal neuralgia and 77 patients with atypical facial neuralgia or pain were treated by oral surgical procedures, with complete or almost complete pain remission in 88% of the cases and without persistent residual anesthesias, dysesthesias, or dysalgesias. The following conditions were related to patients' pain perceptions: cavities in alveolar bone at tooth extraction sites, bone fistulas, periodontal infections, and maxillary sinus infections draining into alveolar bone. The bone cavities and fistulas mentioned above were usually not visualized by standard x-ray diagnostic procedures, and their detection required a new diagnostic approach which is described. Microbiologic findings indicated involvement of a mixed, variable flora in the above conditions. Histopathologic observations of scrapings from involved bone showed a variable incidence of bone necrosis, predominantly chronic inflammatory cell populations and fibrous tissue.

Adult↗
PubMed1984

Collagen production and types in fibrous capsules around breast implants.

This study demonstrates that increased collagen production but not an altered ratio of type III:I collagen is associated with breast capsular contracture. From these findings and previous data, therefore, it appears that capsular contracture is associated with increased foreign-body response biochemically as well as histologically. Further studies are required to directly assess the reasons for contraction around some implants and not others; however, it appears that control of capsular contracture may be achieved by controlling biochemical as well as cellular events associated with contraction. Such studies remain to be done.

Adult↗
PubMed1979

Neonatal rat surgery: avoiding maternal cannibalism.

A simple program of handling and care of pregnant rats before delivery makes it possible to carry out surgical procedures on newborn pups without resultant cannibalism or rejection of the operated animals by their mothers.

Animals↗
PubMed1979

Partial regeneration of the above-elbow amputated rat forelimb. I. Innate responses.

Although a number of recent studies describe the facilitation of limb regeneration by electrical and other forms of stimulation, little is known of innate regenerative capacity in the mammalian limb. The present report describes spontaneous regenerative responses following subtotal forelimb amputation in the young white rat. In one group of animals the forelimb was amputated through the lower humerus and the skin sutured closed. In a second group, adjacent muscle tissue still attached to bone at its origin(s) was interposed between the cut surface of the humerus and the skin. Among animals of the first group (skin closure only) bone growth and limb regenerative responses were generally not observed. Animals of the second group displayed significant elaborations of cartilage and bone at the limb terminus. The appearance and subsequent modification of these tissues suggest that some capacity for limb regeneration exists innately in the young rat and can be more readily evoked than has been recognized heretofore. It is concluded that extant and forthcoming reports of electrically stimulated skeletal tissue growth, repair and regeneration among eutherial mammals should be examined to determine whether reported responses to stimulation represent advances beyond what might be expected from innate replacement processes alone.

Amputation, Surgical↗
PubMed1979

Partial regeneration of the above-elbow amputated rat forelimb. II. Electrical and mechanical facilitation.

This investigation was undertaken to examine the observations of Becker ('72) pertaining to the electrical facilitation of partial limb regenerative responses by means of Ag-Pt wire couples applied to the limb stumps of young, forelimb-amputated white rats. Additionally, in order to examine the possible role of mechanical effects of such device implantations, we have employed uncoupled devices delivering no current or potential difference. In the present experiments, in response to coupled device implantation, cartilage and bone were actively formed in the vicinity of the Pt electrode tip. These tissues contributed to the lengthwise extension of the limb and to the partial restoration of the distal humeral extremity. In limbs bearing the uncoupled electrical devices, qualitatively similar responses were noted, but osteogenesis was diminished in extent compared to that seen in limbs bearing the active or coupled devices. It is therefore necessary to consider the role of mechanical factors in the elicitation of the observed regenerative responses. Myogenesis was enhanced in electrically stimulated limbs, but not in those rats bearing uncoupled devices.

Amputation, Surgical↗
PubMed1979

Etiology and treatment of idiopathic trigeminal and atypical facial neuralgias.

In a series of sixteen patients with idiopathic trigeminal neuralgia and twenty-one patients with atypical facial neuralgia, it was found that the painful phenomena associated with both disorders were, in nearly all instances, closely related to the presence of maxillary or mandibular bone cavities at previous tooth extraction sites. Standard oral surgical procedures for curettage of the cavities, together with administration of antibiotics, were employed in the successful treatment of both the trigeminal and atypical facial neuralgias, with complete pain remissions for periods varying from 2 months (for most recently treated cases) up to 9 years. The observations and results of this study suggest that dental and oral disorders may play a role in the genesis of trigeminal and atypical facial neuralgias.

Adult↗
PubMed1979

Jawbone cavities and trigeminal and atypical facial neuralgias.

The possible role of dental and oral disease in the etiology of idiopathic trigeminal and atypical facial neuralgias has been examined. Among thirty-eight patients with idiopathic trigeminal neuralgia and twenty-three patients with atypical facial neuralgia, there was in nearly all instances a close relationship between pain experienced and the existence of cavities in alveolar bone and jawbone of the patients. The cavities were at the sites of previous tooth extractions and, although at times more than 1 cm. in a given diameter, were usually not detectable by x-rays. A new method for their detection and localization was developed empirically, based on the observation that peripheral infiltration of local anesthetic into or very close to the bone cavity rapidly abolished trigger and pain perception by patients during persistence of the anesthetic action. Histopathologic examination of bone removed from cavities by curettage revealed, in both idiopathic trigeminal and atypical facial neuralgias, a similar pattern characterized by a highly vascular abnormal healing response of bone. Some lesions presented a mild chronic inflammatory (lymphocytic) infiltration. Preliminary microbiologic studies of material from the walls of the cavities showed the existence within them of a complex, mixed polymicrobial aerobic and anaerobic flora. Treatment consisted of vigorous curettage of the bone cavities, repeated if necessary, plus administration of antibiotics to induce healing and filling-in of the cavities by new bone. Responses of patients to the above treatment consisted of marked to complete pain remissions, the longest of which has been for 9 years. Complete healing leads to complete and persistent pain remissions. It was concluded that in both idiopathic trigeminal and atypical facial neuralgias, dental and oral pathoses may be major etiologic factors.

Adult↗
PubMed1977

Absence of mitochondrial terminal respiratory enzymes in cartilage matrix vesicles.

This study attempted to detect evidence of mitochondrial terminal respiratory components in matrix vesicles isolated from rachitic rat tibial epiphyseal plates. Biochemical assays for cytochrome c oxidase, NAD isocitrate dehydrogenase, NADP isocitrate dehydrogenase and succinate-cytochrome c reductase were negative. Polarimetric determinations revealed that the addition of succinate to matrix vesicles in suspension did not cause any increase in oxygen utilization. Spectrophotometric tracings of deoxycholate-solubilized matrix vesicles showed no characteristic absorption peaks or maxima belonging to any of the cytochrome complex components. Attempts to prepare pyridine hemochromes of cytochrome prosthetic groups from the matrix vesicles were also unsuccessful. The above results indicate that key components of mitochondrial respiratory systems are not detectable in rachitic matrix vesicles. The results are compatible with the interpretation that such vesicles are not derived from mitochondria.

Alkaline Phosphatase↗