Effects on labile metabolites of temporal delay in freezing biopsy samples of dog myocardium in liquid nitrogen

Sudden hypothermia utilising liquid nitrogen has been used for immediate inhibition of metabolic reactions and preservation of labile compounds in heart muscle. It has been suggested that this rapid transfer of tissue into liquid nitrogen, within 1 to 2 s, is essential for accurate assessment of internal milieu conditions. We tested this hypothesis in normal dogs by measuring phosphocreatin, ATP, glycogen, and lactate concentrations in transmural layers of a core biopsy taken from the posterolateral wall of the left ventricle frozen immediately in liquid nitrogen or held at room temperature for varying times up to 300 s before freezing the tissue. The earliest significant change occurred in phosphocreatine levels after 60 s; only phosphocreatine demonstrated any changes within the first 120 s. These studies indicate that a delay of up to 30 s may be tolerated before freezing tissue without any change occurring in these labile metabolites.     

Dermatology: a specialty that exemplifies the osteopathic medical profession

Even though the tradition of osteopathic medicine is based in primary care, more osteopathic graduates than in the past are pursuing subspecialties within medicine. Some claim that medical specialties, such as dermatology, compromise osteopathic principles and philosophy. However, the authors contend that dermatology exemplifies the ideals expressed by Andrew Taylor Still, MD, DO, and explain how osteopathic manipulative treatment and the principles of osteopathic medicine can be applied to dermatologic disease and patient care.     

Differential diagnosis of pediatric tumors of the nasal cavity and paranasal sinuses: a 45-year multi-institutional review

We conducted a retrospective case-series review to identify the various diagnoses of neoplasms of the nasal cavity and paranasal sinuses in a pediatric population. Our study group was made up of 54 children-23 boys and 31 girls, aged 8 months to 16 years (mean: 9 yr). All patients had been diagnosed with a tumor of the nasal cavity or paranasal sinuses between Jan. 1, 1955, and Dec. 31, 1999, at one of four university-based, tertiary care referral centers. We compiled data on tumoral characteristics (location, size, and histopathology), morbidity and mortality, and rates of recurrence. Lesions included adnexal neoplasm, ameloblastic fibro-odontoma, basal cell carcinoma, benign fibrous histiocytoma, blue nevus, chondrosarcoma, compound nevus, epithelioma adenoides cysticum, esthesioneuroblastoma, Ewing sarcoma, fibrosarcoma, giant cell granuloma, granulocytic sarcoma, hemangioma, hemangiopericytoma, Langerhans cell histiocytosis, lymphangioma, lymphoma, melanoma, neuroblastoma, neurofibroma, ossifying osteofibroma, osteochondroma, osteosarcoma, port wine stain, rhabdomyosarcoma, Spitz nevus, and xanthogranuloma. To the best of our knowledge, this is the largest such study of its kind to date. We believe that the large size of this study and the data on disease incidence will allow clinicians to be better informed of the differential diagnosis of neoplasms of the nasal cavity and paranasal sinuses in the pediatric population.