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Biomedical subjects

R Shelton

Publications and source records attributed to R Shelton.

At least 19 recordsLinked to original sources
PubMed2001

Mohs micrographic surgery of a plexiform fibrohistiocytic tumor.

BACKGROUND: Plexiform fibrohistiocytic tumor (PFT) is a rare mesenchymal neoplasm first described by Enzinger and Zhang in 1988. Clinically it is characterized by slow growth, frequent local recurrences, and rare systemic metastasis. These tumors occur chiefly in children and young adults and are most commonly located on the shoulders and forearms. OBJECTIVE: To present a case report of an incompletely excised PFT, its complete resection using simple excision and Mohs micrographic surgery, and review of the literature. METHODS: An 11-year-old Hispanic girl was evaluated for the treatment of an incompletely excised plexiform fibrohistiocytic neoplasm located in the right axilla. Mohs micrographic surgery (MMS) was chosen because of the ill-defined borders and the need for tissue conservation. The patient underwent a two-stage, six section, micrographically controlled excision. Upon completion of the MMS a 2 mm final stage, taken as a peripheral and deep section around and underneath the cleared area, was submitted for paraffin embedding. Residual plexiform histiocytic tumor was found at the margin of resection in one location. Reevaluation of the Mohs slides demonstrated the possible presence of tumor at one deep focus. The tumor was reexcised with a 5 mm margin and repeat hematoxylin and eosin staining showed no residual tumor. There has been no evidence of recurrence in 4 years. RESULTS: Complete resection of the PFT and absence of tumor recurrence 4 years later. CONCLUSION: Over the past few years the list of neoplasms for which MMS is the treatment of choice has steadily grown. PFT is a recently described locally aggressive mesenchymal neoplasm with potential for distant metastasis. To our knowledge this is the first time MMS has been used to resect this tumor. To ensure the chance of complete extirpation we recommend the harvest of an additional stage for hematoxylin and eosin staining, as is done in some aggressive squamous cell carcinomas.

Axilla↗
PubMed1999

p53 mutations in basal cell carcinomas arising in routine users of sunscreens.

Sun exposure histories were obtained from a series of patients age 35 or younger following diagnosis and removal of a basal cell carcinoma (BCC). The DNA was extracted from tumor biopsy samples derived from BCC of 10 patients who reported that they did not use sunscreens during youth (age 18 or younger) and 10 patients who routinely employed sunscreens during this age period. Exons 5-9 of the p53 gene were then amplified in three fragments from these samples using a nested polymerase chain reaction (PCR) approach and screened for mutations using an RNA heteroduplex assay. All PCR products displaying evidence of a mutation were sequenced. It was found that 6 of the 10 patients who were not routine sunscreen users displayed mutations in these p53 exons. All of the mutations were located at dipyrimidine sites, five of the six were C-->T transitions and one mutation was a tandem double mutation, consistent with a role for solar UVB in BCC formation. In contrast, only one p53 mutation was detected in the group of 10 patients who routinely employed sunscreens during childhood and adolescence. Hence, a significantly (P = 0.029) lower level of p53 mutations was detected in the BCC obtained from sunscreen users compared with tumors derived from nonusers. These findings suggest that the mechanisms involved in the etiology of skin carcinogenesis differ in sunscreen users compared with people who did not routinely employ sunscreens. These data are also indicative of a protective effect associated with sunscreen use against the formation of p53 mutations. It is possible that the patients who were diagnosed with BCC despite their use of sunscreens possessed a genetic susceptibility for skin cancer formation and developed BCC through a p53-independent pathway. Alternatively, solar UVA wavelengths, that were generally not blocked by the suncare products employed by the sunscreen users, may have played a significant role in BCC development through induction of a mutation(s) in an oncogene and/or a tumor suppressor gene, other than p53, for these patients.

Adolescent↗
PubMed1997

The development of a Marjolin's cancer in a human immunodeficiency virus-positive hemophilic man and review of the literature.

BACKGROUND: The malignant potential of chronic ulcers and scars secondary to a variety of injuries is well characterized in the medical literature. Furthermore, it has been reported that human immunodeficiency virus (HIV)-positive patients have a higher incidence of basal cell carcinoma (BCC) than the general population. OBJECTIVE: To describe a case of an unusually aggressive morpheaform BCC that developed in a 28-year-old HIV-positive patient. The tumor developed in a scar 25 years after the initial trauma (Marjolin's ulcer). METHODS: Description of a case and review of the literature of Marjolins ulcer. RESULTS: The tumor was removed in a seven-stage, 21-section, micrographically controlled excision. Intraoperatively, perineural invasion of the infraorbital nerve was observed. The postoperative defect was repaired using a full-thickness skin graft. CONCLUSION: Although most malignancies arising within chronic scars are SCCs, BCCs and a number of other tumors have been described. Mohs micrographic surgery was effective in treating this aggressive morpheaform BCC. A high degree of suspicion in any changing healed scar is recommended.

Adult↗
PubMed1997

Double-blind comparison of sertraline, imipramine, and placebo in the treatment of dysthymia: psychosocial outcomes.

OBJECTIVE: The purpose of this study was to determine the effects of antidepressant pharmacotherapy on mood symptoms and psychosocial outcomes in dysthymia. METHOD: In a multicenter, double-blind, parallel-group trial, 416 patients with a diagnosis of early-onset primary dysthymia (DSM-III-R) of at least 5 years' duration without concurrent major depression were randomly assigned to 12 weeks of acute-phase therapy with sertraline, imipramine, or placebo. The psychosocial outcome measures used in the study were the Global Assessment of Functioning Scale, the Social Adjustment Scale, the Longitudinal Interval Follow-up Evaluation psychosocial ratings, and the Quality of Life Enjoyment and Satisfaction Questionnaire. RESULTS: Sertraline and imipramine were significantly better than placebo in improving psychosocial outcomes as measured by the first three instruments. The Quality of Life Enjoyment and Satisfaction Questionnaire scores demonstrated significant improvements from baseline, and both active treatments produced significantly greater improvements than placebo. Significantly fewer patients discontinued sertraline (6.0%) than discontinued imipramine (18.4%) because of adverse events. CONCLUSIONS: Pharmacotherapy is an effective treatment for dysthymia in terms of psychosocial functioning as well as depressive symptoms, even when the dysthymia is long-standing.

1-Naphthylamine↗
PubMed1997

Immunizing preschool children: beliefs and practices of pediatric residents.

Immunization practices and knowledge of vaccine contraindications among pediatric residents were assessed at five pediatric training facilities by surveying 227 pediatric residents. Residents administer vaccines even in the presence of an afebrile minor illness. They are less likely to vaccinate if a fever (< 102 degrees F) is present. Only 57% of residents report administering vaccines at the 15-month well-child checks. Many residents had difficulty recognizing true and false contraindications, though third-year residents did better than first-year residents. Failure during residency to utilize 15-month well visits and ill visits in the presence of a fever and the lack of knowledge of true and false vaccine contraindications may be causes of missed opportunities to vaccinate among residents. Immunization practices resulting in missed opportunities to vaccinate seen during during residency may influence later immunization practices.

Child, Preschool↗
PubMed1993

Linear bacterial dissection.

An unusual case of an erythematous indurated arcuate plaque with a curvilinear appearance was noted after a patient manipulated an ingrown beard hair. During removal of a biopsy specimen, a purulent discharge was expressed that had evidently dissected through the dermis forming this interesting shape. This may be similar to a recently reported entity described by Shelley and Shelley as linear bacterial dissection. Culture of the discharge grew Staphylococcus aureus and Klebsiella pneumoniae. Complete resolution occurred after drainage and antibiotic therapy. Cellulitis and erysipelas typically do not show central clearing or form arcuate plaques. Aside from lymphangitis, thrombophlebitis, and sinus tracts of carbuncles, dermal infectious processes rarely present as linear or arcuate plaques. The differential diagnosis and a review of the literature are presented.

Adult↗
PubMed1992

Psychiatric phenomenology in Cushing's disease.

We evaluated 20 patients with Cushing's disease (i.e., Cushing's syndrome due to ACTH-secreting pituitary microadenoma) and 20 patients with Major Depressive Disorder (MDD) using the Structured Clinical Interview for DSM-III-R (SCID) and Research Diagnostic Criteria. The diagnosis of Generalized Anxiety Disorder (GAD) was most common in Cushing's disease (79%), followed by MDD (68%), and Panic Disorder (PD) including subthreshold PD (53%). The combination of MDD and GAD and/or PD was also common in Cushing's disease (63%). Behavioral symptoms, if present, usually first occurred at or after the onset of the first physical symptoms. However, the onset of PD was associated with more chronic stages of Cushing's disease. In both Cushing's disease and MDD, more female than male relatives suffered from MDD, whereas more male than female relatives suffered from substance abuse. The data demonstrate a syndrome of anxious depression in patients with active Cushing's disease; such comorbidility has not been previously noted. The data also point to intriguing epidemiological, clinical, and biological associations between Cushing's disease, MDD and substance abuse.

Adolescent↗
PubMed1991

The nucleus basalis of Meynert, senile plaques, and intellectual impairment in schizophrenia.

The large, hyperchromic, cholinergic neurons of the nucleus basalis of Meynert (nbM) and the presence of senile plaques were quantified in postmortem brain tissue from 10 intellectually impaired schizophrenic patients, seven intellectually intact schizophrenic patients, seven control subjects, and three patients with Alzheimer's disease. The two groups of schizophrenic patients did not show any significant differences when compared with the control group in nbM cell density or in plaque frequency. The Alzheimer's disease patients showed the expected decrease in nbM neuronal density and increase in plaques compared with the controls. The data suggest that compromised cognitive function in schizophrenia is not associated with diffuse neuropathology of the basal forebrain cholinergic system.

Acetylcholine↗
PubMed1990

In vivo estimation of perfluorooctylbromide concentration in tissues.

Currently, the only available method to measure perfluorooctylbromide (PFOB) in tissues requires its extraction with a solvent followed by gas chromatography. Not only is this method invasive, but it cannot be validated because the amount of unextracted PFOB is unknown. Using a cylindrical CT phantom with eight wells in the wall filled with bromine (Br) standards, an in vivo method to measure PFOB tissue concentration was developed. Neutron activation analysis (NAA) was used to calibrate and validate the phantom since NAA allows the quantification of Br by making Br radioactive without the need for extraction. Once NAA was validated for PFOB, the phantom was calibrated using 80 rats and tested using 20 rats relative NAA. The phantom produced linear correlation between CT number and known PFOB concentrations with r = 0.998. After its calibration with NAA, the CT method produced a linear correlation between tissue PFOB concentration determined by CT and NAA near the line of identity with an r = 0.984, thus allowing the determination of PFOB tissue content in vivo noninvasively.

Animals↗
PubMed1987

Subcutaneous administration of gonadotropin-releasing hormone: absorption kinetics and gonadotropin responses.

To evaluate the suitability of the sc route for the pulsatile delivery of GnRH, plasma GnRH, LH, and FSH levels were measured by RIA in five women with hypothalamic amenorrhea after sc injection of single doses of 2.5, 5, and 10 micrograms GnRH. The results were compared with those obtained after bolus iv injection of 10 micrograms GnRH. After sc injection, plasma GnRH levels rose to a dose-related maximum after 5-10 min and fell to less than 10% of the peak value by 90 min. The mean plasma disappearance half-time was 24 min (range, 18-30 min). After bolus iv injection, an initial rapid phase of disappearance (t1/2, 2.8 min) was followed by a slower phase (t1/2, 33 min), falling within the 95% confidence intervals for the disappearance half-time after sc administration (12-36 min). The patterns of LH response to sc and iv GnRH were similar, with maximum levels reached between 20 and 30 min after injection, then declining to 50-69% of the peak value by 90 min after sc injection and 61% of the peak value 90 min after iv injection. There was no significant difference between peak LH responses to 10 micrograms iv and sc doses of GnRH [15.2 +/- 2.5 (+/- SEM) vs. 13.2 +/- 2.2 IU/L]. Subcutaneous administration of three consecutive GnRH pulses at 90-min intervals to four women resulted in gonadotropin responses to each GnRH pulse. We conclude that sc GnRH administration results in pulsatile plasma GnRH and gonadotropin responses, the latter resembling those seen after iv GnRH. These results confirm the suitability of the sc route for pulsatile GnRH delivery.

Absorption↗
PubMed1987

The assessment of nonroutine situations by pilots: a two-part process.

A pilot encountering a nonroutine event must make a decision based on what may often result from a two-part process. The first is the diagnosis of the nature of the nonroutine event (Assessment A), followed by a determination of the potential consequences of that event (Assessment B). Analyses of aircraft accidents and incidents show that overestimation or underestimation in Assessment B can be a serious determinant of pilot misjudgment, even though Assessment A was entirely accurate.

Accidents, Aviation↗