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Biomedical subjects

R J Smith

Publications and source records attributed to R J Smith.

At least 271 records · Page 15Linked to original sources
PubMed1994

Toxic shock syndrome associated with suction-assisted lipectomy.

Toxic shock syndrome (TSS) is a serious, potentially life-threatening condition resulting from an exotoxin of Staphylococcus aureus. Presenting symptoms include high fever, diarrhea, nausea, and vomiting progressing to hypotension, oliguria, conjunctival hyperemia, and an erythematous rash over the trunk, abdomen, and extremities. TSS has been associated both with and without the use of tampons during menstruation, postsurgical infections, and stab wounds, and can occur in postrhinoplasty patients with and without nasal packing. There has been one case reported in the literature of TSS associated with suction-assisted lipectomy (SAL). This article discusses the diagnosis and treatment of two cases in which the patients developed TSS after outpatient use of SAL. In the first case, an abdominoplasty and SAL were performed in a healthy young female. The second case involved the harvesting of abdominal fat via syringe suction and subsequent facial fat injection in a female with systemic lupus erythematosus and severe facial atrophy.

Adult↗
PubMed1994

Role of perivenous areolar tissue and recipient bed in the viability of venous flaps in the rabbit ear model.

This study was performed to investigate the role of perivenous areolar tissue and flap bed in the viability of venous flaps in the rabbit ear model as described by Inada et al. Six groups of flaps were studied: group A--flap based on a proximal vein and areolar tissue; group B--flap based on a proximal venous pedicle which has been skeletonised; group C--flaps based on a proximal vein and areolar tissue sutured over a full thickness skin graft (FTSG), preventing diffusion into the flap; group D--flaps with a skeletonised pedicle sutured over a FTSG; group E--control, non-vascularised flap placed directly on bed; and Group F--control, non-vascularised flap sutured over a FTSG. Groups C and D had 15 flaps and the remaining groups had 10 flaps in each. All flaps in groups A and B had total or partial survival. In group C 4 flaps survived completely, 8 had partial survival and 3 necrosed. Group D had only 2 flaps with partial survival with 13 flaps with total loss. In group E there were 10 flaps with partial survival and none with complete loss. No flaps in group F survived. Histological examination of the pedicle showed small vascular channels present in the areolar tissue surrounding the venous pedicle. This study confirms the importance of the perivenous areolar tissue in the perfusion of the venous skin flap in the rabbit ear model.

Animals↗
PubMed1994

Dual infections with Staphylococcus aureus and Streptococcus pyogenes causing toxic shock syndrome. Possible synergistic effects of toxic shock syndrome toxin 1 and streptococcal pyrogenic exotoxin C.

We describe a 35-year-old woman with clinical, microbiologic, and serologic findings suggesting that the patient developed toxic shock syndrome as a result of dual infections caused by toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. Certain aspects of the pathogenesis of this toxin-related syndrome are reviewed.

Adult↗
PubMed1994

New bioactive taxoids from cell cultures of Taxus baccata.

Four new taxoids were isolated from cell cultures of Taxus baccata. Their structures were elucidated by spectroscopic analyses. Two were the aglycones corresponding to previously isolated 7-O-xylosides of taxol C [1] and 10-deacetyltaxol C [2]. The third [3] had an N-methylated side-chain, while the fourth, named taxcultine [4], contained an n-propyl group on the side-chain. All four compounds actively promoted tubulin assembly. Taxol C [1] showed potent and selective cytotoxicity in the NCI human cell line screen.

Antineoplastic Agents, Phytogenic↗
PubMed1994

Detecting plant silica fibres in animal tissue by confocal fluorescence microscopy.

Silica fibres from the inflorescence bracts of the grass Phalaris canariensis L. cause dermatitis, and have been implicated in the aetiology of oesophageal cancer in northeastern Iran. Here we describe a method for labelling these fibres so that they can be located in mammalian tissue. Fluorescein was covalently linked to isolated, purified fibres with the silane coupling agent 3-aminopropyl triethoxysilane. The labelled hairs were then rubbed into the backs of mice. These were later killed and their skin fixed, stained and sliced at a thickness of 250 microns. A confocal laser scanning microscope gave brilliant images of the fibres at any depth up to 100 microns or more beneath the surface of the slice. Fibres penetrated deeply into the dermis. Several cubic millimetres of tissue could be surveyed in 1 h. The number of fibres present was approximately 2 mm-3 initially, falling to 0.1 mm-3 after 7 days.

Animals↗
PubMed1994

Case report: purpura in disseminated strongyloidiasis.

Purpuric lesions have been described previously in 10 patients with disseminated strongyloidiasis. We identified three additional patients in whom purpura developed as a manifestation of disseminated strongyloidiasis. Nine (69%) of the 13 patients were men, and the median age of patients was 61 years (range, 32-75 years). Six patients were from the southeastern United States. Six patients had underlying malignancy and four patients had chronic lung disease. All patients had received prior corticosteroids. The parasite was identified in 11 (92%) of 12 patients where stool or sputum examination was performed. Skin biopsies of purpuric lesions were obtained in 12 patients, in 10 (83%) of which larvae were found. Despite recommended treatment with thiabendazole in 12 of 13 patients, 11 (85%) of the patients died, and at least 6 died within 16 days of onset of purpura. Physicians, particularly those in the southeastern United States, should strongly consider the diagnosis of disseminated strongyloidiasis in patients receiving corticosteroids and in whom purpura and systemic toxicity develops.

Adrenal Cortex Hormones↗
PubMed1994

Estimating upper confidence limits for extra risk in quantal multistage models.

Multistage models are frequently applied in carcinogenic risk assessment. In their simplest form, these models relate the probability of tumor presence to some measure of dose. These models are then used to project the excess risk of tumor occurrence at doses frequently well below the lowest experimental dose. Upper confidence limits on the excess risk associated with exposures at these doses are then determined. A likelihood-based method is commonly used to determine these limits. We compare this method to two computationally intensive "bootstrap" methods for determining the 95% upper confidence limit on extra risk. The coverage probabilities and bias of likelihood-based and bootstrap estimates are examined in a simulation study of carcinogenicity experiments. The coverage probabilities of the nonparametric bootstrap method fell below 95% more frequently and by wider margins than the better-performing parametric bootstrap and likelihood-based methods. The relative bias of all estimators are seen to be affected by the amount of curvature in the true underlying dose-response function. In general, the likelihood-based method has the best coverage probability properties while the parametric bootstrap is less biased and less variable than the likelihood-based method. Ultimately, neither method is entirely satisfactory for highly curved dose-response patterns.

Animals↗
PubMed1994

Differential responsiveness of human bronchial epithelial cells, lung carcinoma cells, and bronchial fibroblasts to interferon-gamma in vitro.

The present study examines interferon-gamma (IFN gamma)-induced changes in the expression of immunomodulatory genes, proliferation-associated genes, and squamous-specific genes in primary cultures of human bronchial epithelial cells and fibroblasts. IFN gamma induced the expression of guanylate binding protein (GBP or p67) and the MHC class II antigen, HLADR alpha, in both epithelial cells and fibroblasts. In contrast, the expression of complement component C3 was induced in bronchial epithelial cells but not in fibroblasts. Similarly, IFN gamma induced growth arrest (EC50 approximately 50 U/ml) only in bronchial epithelial cells. This growth arrest was accompanied by a down-regulation of cdc2, E2F-1, and p53 mRNA levels and was associated with expression of the squamous-specific marker genes, transglutaminase type I and cornifin. These findings are consistent with IFN gamma inducing squamous differentiation in bronchial epithelial cells. In contrast, several lung carcinoma cell lines did not respond to IFN gamma with respect to the down-regulation of proliferation-associated genes or the induction of squamous-specific genes. However, GBP expression was induced in all the cell lines in response to IFN gamma. The present study demonstrates that cultured human bronchial epithelial cells are sensitive to the immunomodulatory, growth-inhibitory, and differentiation-inducing properties of IFN gamma. In contrast, several lung carcinoma cell lines are insensitive to the growth-inhibitory and differentiation-inducing actions of IFN gamma, suggesting they may have acquired defects in certain IFN gamma signaling pathways. Although the growth of human bronchial fibroblasts is not altered, expression of certain immunomodulatory genes is induced by IFN gamma.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchi↗
PubMed1994

Acyclovir in the treatment of recurrent respiratory papillomatosis. A pilot study.

Six patients with severe, recalcitrant, juvenile-onset recurrent respiratory papillomatosis were treated with 7 independent trials of acyclovir. In 2 trials, patients received acyclovir in place of interferon-alpha; the remaining 5 trials were in patients not otherwise receiving chemotherapy. Quantitative analysis of overall disease extent, laryngeal involvement, and degree of glottic obstruction for the 6 months prior to acyclovir administration and during acyclovir administration demonstrated a statistically significant decrease in all parameters evaluated in those patients who were otherwise unmediated. The 2 patients who discontinued interferon-alpha immediately prior to beginning acyclovir demonstrated worsening disease, consistent with the well-recognized rebound phenomenon associated with stopping interferon. This study suggests that acyclovir decreases the extent of respiratory papillomatosis in patients with recalcitrant disease. The beneficial effect of acyclovir appears to be insufficient to counteract the rebound of disease when interferon is stopped abruptly.

Acyclovir↗
PubMed1994

Interarytenoid notch height relative to the vocal folds. Pilot study.

We measured interarytenoid notch height (IANH) in 20 young children who required direct laryngoscopy under general anesthesia. By means of a specifically designed instrument, we found that the average IANH approximated 3 mm. Laryngeal incompetence on swallowing or in the presence of gastroesophageal reflux is associated with a low IANH (p < .0001). Therefore, IANH may be a measure of relative laryngeal incompetence.

Age Factors↗
PubMed1994

Polymerase chain reaction amplification of herpes simplex viral DNA from the geniculate ganglion of a patient with Bell's palsy.

Bell's palsy is the most common cause of facial paralysis. In this study, we demonstrate the presence of herpes simplex viral type 1 (HSV-1) genomic DNA in the geniculate ganglion of a patient who had Bell's palsy. This association suggests that in this patient, HSV-1 may have caused Bell's palsy. If HSV-1 is a cause of Bell's palsy, treatment with acyclovir may be beneficial. Additional studies should be done to establish the prevalence of HSV-1 as an etiologic agent of Bell's palsy.

Aged↗
PubMed1994

Reflex laryngospasm induced by stimulation of distal esophageal afferents.

Distal esophageal sensory nerves were stimulated in 17 anesthetized dogs divided into three age groups to determine the laryngeal, cardiovascular, and respiratory effects. Group I puppies were 5 to 6 weeks of age, group II puppies were 8 to 19 weeks of age, and group III animals were adult dogs. Marked laryngeal adductor activity and laryngospasm were observed in group II puppies, while no or minimal laryngeal adduction was seen in younger puppies and adult dogs. Mean arterial pressure and heart rate increased significantly in groups II and III (P < .005) but remained unchanged in group I animals (P > .4). This response is distinctly different from the laryngeal chemoreflex because central apnea, hypotension, and bradycardia were absent. The afferent limb of the response is mediated by the vagus nerve as bilateral transthoracic truncal vagotomy eliminated the reflex. The laryngeal response observed following stimulation of distal esophageal afferent fibers may be important in the mechanism of apparent life-threatening events (ALTEs) and the sudden infant death syndrome (SIDS) associated with gastroesophageal reflux disease.

Afferent Pathways↗
PubMed1994

Abnormal movement of the arytenoid region during exercise presenting as exercise-induced asthma in an adolescent athlete.

A 16-year-old female basketball player presented with a 2 1/2-year history of exercise-induced severe dyspnea, stridor, and mild wheezing that did not respond to prophylactic treatment with beta-agonists and cromolyn. Spirometric data at rest were normal, but flow-volume loops during exercise suggested a variable extrathoracic obstruction. Laryngoscopic evaluation while the patient was riding an exercise bicycle demonstrated an abnormal motion of the arytenoid region causing obstruction of the airway during inspiration. The vocal cords moved normally. This patient demonstrates the capacity of supraglottic tissue to obstruct the airway during exercise as a cause for exercise-induced dyspnea and stridor. Patients with this disorder may be misdiagnosed as having exercise-induced asthma.

Adolescent↗
PubMed1994

Anatomy and significance of the temporal fat pad in Apert syndrome.

Abnormal temporal region anatomy in Apert syndrome described in the literature includes inferior and lateral displacement of the middle cranial fossa, effacement of the temporal fossa, and thinning of the temporalis muscle. Four patients with Apert syndrome were noted to have hyperplasia of the bilateral superficial temporal fat pads, which could be contoured surgically. A case is presented with reformatted three-dimensional computed tomography (3-D CT) scans with intraoperative documentation of increased temporal fat as compared to normal controls.

Acrocephalosyndactylia↗