Correctional nursing: an insider's view.
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Biomedical subjects
Publications and source records attributed to P Cline.
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Receptor binding studies have demonstrated the presence of an [3H]MK-801 ([3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-im ine maleate) binding site in human keratinocytes. The affinity found in keratinocytes was lower than that found in brain membranes. Northern blots identified mRNA in human keratinocytes and rat cardiocytes, as well as rat brain, that hybridized with high stringency to a probe for NMDAR1, an NMDA receptor subunit. In each tissue, mRNA that hybridized to another glutamate binding protein that might be part of an NMDA receptor complex, was also present. The presence of NMDA or NMDA-like receptors in keratinocytes and rat cardiocytes together with the low affinity [3H]MK-801 binding suggests that this protein may be a general channel forming protein that is present in many tissues, and forms specific receptors by interacting with additional subunits.
In this study we examined the different aspects of the pathway leading to the differentiation of keratinocytes as a function of time in culture and calcium concentration of the culture medium. Human neonatal foreskin keratinocytes were grown in a serum-free, defined medium containing 0.07, 1.2, or 2.4 mM calcium and assayed for the rate of growth and protein synthesis, involucrin content, transglutaminase activity, and cornified envelope formation at preconfluent, confluent, and postconfluent stages of growth. We observed that keratinocytes grown to postconfluence in all calcium concentrations showed an increased protein/DNA ratio and an increased rate of membrane-associated protein synthesis. Extracellular calcium concentrations did not have a clear influence on these parameters. However, preconfluent and confluent keratinocytes grown in 0.07 mM calcium showed markedly retarded differentiation at all steps, i.e., involucrin synthesis, transglutaminase activity, and cornified envelope formation. Within 1 week after achieving confluence, these keratinocytes began synthesizing involucrin and transglutaminase and developed the ability to form cornified envelopes. Cells grown in 1.2 and 2.4 mM calcium synthesized involucrin and transglutaminase prior to confluence and were fully competent to form cornified envelopes by confluence. Thus external calcium-regulated keratinocyte differentiation is not an all or none phenomenon, but rather it is the rate at which keratinocytes differentiate that is controlled by calcium. We conclude that either or both higher extracellular calcium concentration and the achievement of cell-cell contacts lead to a coordinate increase of at least two precursors--involucrin content and transglutaminase activity--required for cornified envelope formation. We speculate that a critical level of cytosolic calcium, achieved by increased extracellular calcium or by achievement of intercellular communication established by cell-cell contact, may trigger mechanisms required for initiation of keratinocyte differentiation.
Anterior pituitary insufficiency in patients with traumatic brain injury is rare. Only sporadic cases have been reported in the literature. The authors report a case of panhypopituitarism that developed in a 19-year-old man and was diagnosed six months after the patient sustained severe craniocerebral trauma in a motor vehicle accident. After an initial slow improvement in neurologic function he very gradually retrogressed in physical and mental capacities. An acute adrenal crisis led to the diagnosis of hypopituitarism. Institution of appropriate hormone therapy resulted in steady improvement in motor and cognitive functioning. The authors reviewed the literature and discuss the possible pathophysiology. They exhort physiatrists to be aware of this rare but potentially fatal consequence of craniocerebral trauma.