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Biomedical subjects

J M Morehead

Publications and source records attributed to J M Morehead.

5 recordsLinked to original sources
PubMed1994

Soft-tissue response to synthetic biomaterials.

The soft-tissue response to an implanted synthetic material is an inflammatory reaction to foreign body; factors that minimize this inflammation will maximize biocompatibility. The ideal implant is selected from a material that is non-toxic, nonantigenic and in chemical proximity to calcium or carbon on the periodic table. If it is porous, the pores should be large enough to admit immune and phagocytic cells and ideally, to allow native tissue ingrowth. The implant should be of appropriate size and shape and should be implanted in the correct location. The material should be nonparticulate, should resist fragmentation, and should be secured in the selected location after gentle insertion. All these factors help decrease the body's natural response to an implanted foreign body, but inflammation and foreign body reaction are the common threads in all responses to all implanted synthetic materials. Optimum soft-tissue biocompatibility, characterized either by thin fibrous encapsulation or by mesenchymal ingrowth into pores and interstices, is achieved by avoiding or containing this response.

Biocompatible Materials↗
PubMed1993

Tracheobronchomalacia in Hunter's syndrome.

Hunter's syndrome is one of a group of heritable metabolic disorders caused by decreased activity of one or more of the lysosomal enzymes responsible for mucopolysaccharide catabolism, resulting in excessive deposition of mucopolysaccharides in skeletal and soft tissues. Pulmonary conditions, such as airway obstruction, sleep apnea syndrome, atalectasis, recurrent pneumonia and difficult endotracheal intubation are known to be associated with these rare disorders and have been reported. We report the findings at laryngotracheobronchoscopy of a patient with Hunter's syndrome with airway symptoms and, supported by analysis of previously reported cases of airway problems associated with the syndrome, suggest that tracheobronchomalacia with classifiable major airway collapse (MAC) may be the pathological correlate for this clinical picture. The endoscopic technique and characteristic findings of tracheobronchomalacia/MAC are discussed, as well as the natural history and pathophysiology of this condition, which is characterized by weakness of the tracheal wall due to softening of the supporting cartilage and hypotonia of the myoelastic elements with reduction in the tracheal lumen.

Airway Obstruction↗
PubMed1993

Squamous cell carcinoma of the tongue occurring as a subsequent malignancy in a 12-year-old acute leukemia survivor.

Squamous cell carcinoma of the tongue is rare in children and previously unreported as a second malignancy after survival of acute leukemia. Usual etiologic associations such as smoking and alcohol use are not commonly seen in this population, and exposure to immunosuppressive and antineoplastic agents including radiation therapy may contribute to the occurrence of these tumors. A review of the literature reveals only 21 previously reported cases of squamous cell carcinoma of the tongue in children less than 15 years old, and in only two cases was it a second malignancy; none were in leukemia survivors. Small numbers prevent accurate conclusions with regard to tumor behavior, but prognosis appears to be poor with aggressive invasion and early metastasis common. Follow-up of survivors of leukemia and its therapy with immunosuppressive and cytotoxic drugs and radiation should include regular careful head and neck examinations.

Carcinoma, Squamous Cell↗