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Biomedical subjects

J A Dean

Publications and source records attributed to J A Dean.

At least 19 recordsLinked to original sources
PubMed1998

The Platelet Function Analyzer (PFA-100): a novel in-vitro system for evaluation of primary haemostasis in children.

The PFA-100 system provides an in-vitro method of assessing primary platelet-related haemostasis by measuring the time (the closure time, or CT) taken for a platelet plug to occlude a microscopic aperture cut into a membrane coated with collagen and either epinephrine or ADP. We used the system to establish normal ranges for CTs in healthy children, adults and neonates. Mean CTs of healthy children were independent of the needle gauge used (21G or 23CG) for blood sampling; they were very similar to the mean CTs of healthy adults, but longer than mean CTs of healthy neonates. Although children with haemophilia had normal CTs, the PFA-100 system was found to be potentially useful in screening for von Willebrand disease in children.

Adolescent↗
PubMed1997

One-stage reconstruction for defects caused by cancrum oris (noma).

Cancrum oris is a disease process that has been described for centuries, but now presents primarily in developing countries. The disease in known to occur in association with poor nutrition and exanthematous infections. The acute disease occurs usually in young children, and the infectious process causes destruction of the involved orofacial tissues with variable degrees of tissue loss and scar reaction in those who are affected and survive. The chronic sequelae of the acute disease process often require reconstructive surgery. We present the natural history of the disease process and its causes, and demonstrate the wide spectrum of resulting defects that challenge the reconstructive surgeon. Because of the socioeconomic situation inherent with these patients and the volume of patients in need of treatment with this disease, innovative and efficient treatment is required. We have demonstrated methods of reconstructive surgery that differ from the multiple staged procedures described in previous studies by allowing for one-stage surgical reconstruction of even the most complex cases. This allows for treatment of the majority of patients in their native countries in a cost-effective and safe manner, and treatment of more severely afflicted individuals in modern medical centers without their having to spend a long time period away from their homes.

Adult↗
PubMed1997

Progression of interproximal caries in the primary dentition.

While studies have addressed the diagnosis and progression of interproximal carious lesions within a primary tooth, few studies have addressed the development of proximal lesions in adjacent primary molars. The purpose of this study was to examine retrospectively the long term interproximal caries progression in primary molar teeth. Dental records of 150 children were retrospectively reviewed, 76 from a university pediatric dentistry clinic and 74 from a pediatric dentistry private practice. Out of the 387 teeth initially diagnosed with proximal caries, the combined university and private practice results for timing of the development of proximal lesions on adjacent tooth surfaces showed the following: simultaneous development-162 (41.9%); 1 to 24 months-65 (16.8%); 24 to 60 months-40 (10.3%); never-120 (31.0%). The combined results for formation of proximal caries in posterior quadrants showed that out of the 150 patients, the timing for development of additional quadrants with proximal caries was as follow: simultaneous development: 77 (51.3%); 1 to 24 months 31, (20.7%); 24 to 60 months 25, (16.7%); never 17 (11.3%). The conclusions of the study are that 69% of the primary molar teeth with proximal caries developed caries on the adjacent proximal surface and 89% of the patients who developed a proximal carious lesion on a primary molar tooth within one quadrant developed another primary molar proximal lesion in another quadrant.

Child↗
PubMed1996

Using a resin-modified glass ionomer as an occlusal sealant: a one-year clinical study.

The authors compared the retention and clinical performance of a resin-modified glass ionomer, or RMGI, restorative and a light-cured resin sealant. The first permanent molars on one side of the dental arch in 50 children were sealed with an RMGI, and the same teeth on the other side were sealed with a resin sealant. At baseline, six months after placement and one year after placement, examiners documented sealant retention, secondary caries, marginal discrepancy and marginal staining. In general, the RMGI appeared to wear markedly. At one year, the retention of the RMGI was significantly less than the resin, but the RMGI had significantly fewer marginal discrepancies. There were no significant differences in caries development or marginal discoloration.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1992

The brow slide: a technique for the aesthetic treatment of eyebrow tumors.

Skin neoplasms involving the eyebrow are not an uncommon problem. Standard surgical resections that depend on elliptical excision and closure tend to either remove an excessive amount of brow or place scars in an unfavorable position. We present a simple technique that allows for maximal brow preservation, alignment of remaining brow, and a minimal amount of exposed scars.

Aged↗
PubMed1991

Diphallia and hindgut duplication.

Diphallia is a rare congenital condition that presents in many, varied ways. Associated anomalies are to be expected. These anomalies should be sought out and treated as early in the patient's life as possible because they are the principal cause of mortality in these individuals. Half the patients reviewed by Ravitch in 1953 with duplication of the colon and genital tracts died of intestinal complications. Definitive genital repair should be done at an age where the anatomy is of large enough caliber for eased surgical manipulation, but prior to the age of recall. From our experience with hypospadias repair, the optimal age seems to be 12 months of age. Each case must be treated individually in order to achieve the best functional and aesthetic result.

Adolescent↗
PubMed1990

Software for data management and analysis in epidemiology.

The collection of data is a lengthy and time-consuming process, but is not an end in itself. For the data to be useful, it is necessary for an appropriate analysis to be made and its results applied. This article describes a computer program for the analysis of epidemiological studies.

Data Interpretation, Statistical↗
PubMed1988

Pharmacological control of the pattern of activity in leech Retzius neurones.

1. Changes in the activity pattern of leech Retzius (R) cells were investigated using intracellular recording. 2. The presence of an after-hyperpolarisation (AHP) is closely related to activity pattern; regular firing being associated with an AHP, bursting with its absence. 3. Increasing external calcium (Cao), cyclic AMP levels or activity of kinase A enhanced the AHP. 4. Bursting was induced by low Cao, EGTA, barium, cobalt or injection of phorbol ester. 5. Reduction of Cao to zero caused long paroxysmal depolarising shifts of potential which could be reversed to bursting by cobalt, IBMX or injection of kinase A catalytic subunit. 6. The possible roles of a calcium-activated potassium channel and protein phosphorylation in regulating the activity of the cell are discussed.

1-Methyl-3-isobutylxanthine↗
PubMed1985

A new approach to the analysis of complex dose-response relationships: a multivariate study of octopamine action on the leech Leydig neurone.

Octopamine (OA) hyperpolarizes leech Leydig neurones but response amplitudes and thresholds vary. Associations between response, OA dose and other variables [initial resting potential, action potential (AP) frequency and amplitude, temperature, microelectrode resistance, position of ganglion along nerve cord, animal, treatment order] were examined using canonical correlation. A complex response was expressed by summing changes in membrane potential and AP frequency over 2 min of OA treatment. Only dose and ganglion position influenced this response. One significant canonical variate related dose to immediate changes in membrane potential and summed changes in AP frequency throughout the OA effect. Response to OA was greater in cells in posterior ganglia.

Action Potentials↗
PubMed1980

Medical and nutritional aspects of intractable diarrhea.

Diarrhea can be due to at least five pathogenetic mechanisms. Major examples of each are presented to better illustrate each type of diarrhea and to provide a springboard for discussion of the nutritional management of each class of diarrhea. Certainly, specific diseases require specific therapies, such as avoidance of gluten in adult coeliac disease, but the major dietary/nutritional alterations and subsequent treatment are similar for each class of disease. Nowhere in medicine and nutrition is an admonition to the health care team more important and more proper than in the treatment of chronic diarrheas: The feeding of healthy man, as well as the diet of the sick cannot be left to chance, guided by the appetite, or ruled by tradition, but can be safely directed only according to the laws of digestion and metabolism.

Adult↗
PubMedDate not supplied

Reconstruction of traumatically acquired defects of the phallus.

Trauma to the male phallus may be treated in a systematic approach to achieve aesthetically and functionally pleasing results. Isolated burns should be treated early with excision and preputial flap or skin graft closure. Avulsion injuries are closed primarily or skin grafted. Subtotal loss can be treated with penile lengthening techniques. Total loss is treated with reimplantation or microvascular free tissue transfer phalloplasty. There are reconstructive surgical options, instead of penectomy, in patients with penile malignancies.

Amputation, Traumatic↗