Identification of a by-product of nitric oxide synthase activity in human acute brain injury with in vivo proton magnetic resonance spectroscopy

BACKGROUND AND PURPOSE: Laboratory studies have been used to identify nitric oxide as a notable mediator in neuronal death after acute brain injury. To our knowledge, this has not previously been confirmed with in vivo study in humans. Our purpose was to seek in vivo evidence for the induction of nitric oxide synthase (NOS) in human acute brain injury by using proton MR spectroscopy.

METHODS: In vitro proton MR spectra were obtained in neural extracts from 30 human cadavers, and in vivo spectra were obtained in 20 patients with acute brain injury and in a similar number of control subjects.

RESULTS: We identified a unique peak at 3.15 ppm by using in vivo proton MR spectroscopy in eight of 20 patients with acute brain injury but not in 20 healthy volunteers (P < .002). On the basis of in vitro data, we have tentatively assigned this peak to citrulline, a NOS by-product.

CONCLUSION: To our knowledge, our findings suggest, for the first time, that excitotoxicity may occur in human acute brain injury. Confirmation with the acquisition of spectra in very early acute cerebral injury would provide a rationale for the use of neuroprotective agents in these conditions, as well as a new noninvasive method for quantification.

Care needs and functional status of older acute care patients

A growing number of older adults are admitted to hospitals, and information is needed on how age-related functional decline affects nursing care needs of this population. This study compared the functional status at admission and total nursing care needs of three age groups of older inpatients. A 12-month retrospective audit was performed on the records of 225 patients in a private metropolitan hospital. The three groups of patients were matched on diagnosis. Findings revealed that older patients were significantly more dependent, had greater total nursing care needs, and were less likely to be discharged to home, indicating that in addition to medical diagnoses, age-related differences of older patients’ functional status at admission and inpatient nursing care needs should be factored into staff workloads and funding of nursing care. The finding that significantly fewer of the older patients returned home must be considered when reviewing health care policy and services.