The ability of hemoglobin and myoglobin to bind nitric oxide (NO) produced by other cells and circulating vasodilators is well known. To characterize erythrocytes (RBCs), we used NADPH diaphorase labeling, as well as antibodies to the three known types of NO synthase (NOS 1, 2, and 3), and to a molecule usually associated with NOS, calmodulin. We show that the NADPH-diaphorase label labels myenteric neurons, endothelial cells, and the blood cells trapped in the lumen of the blood vessels running through the intestinal wall. The myenteric neurons are also positive for neuronal NOS (NOS1), calmodulin, and neuropeptide Y, indicating that they are NO-producing neurons. Endothelial cells are positive for NOS3 (a constitutive form of NOS), while macrophages and lymphocytes are positive for NOS2 (an inducible form of NOS). All are positive for calmodulin. Surprisingly, the RBCs are positive for NOS2 and 3, as well as calmodulin. Thus the RBCs possess all the cellular machinery to synthesize their own NO. We suggest that erythrocytes would synthesize and use NO to modulate their own physiology.

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We studied micturitional reflexes in 46 unanesthetized adult male cats spinalized at C5-C6 17 to 125 days previously and in eight intact central nervous system chloralosed cats that were used as controls. Urethral pressure profiles, cystosphincterograms with the urethrovesical junction opened and closed, and mechanograms of detrusor and circular and longitudinal urethral muscles were performed. The effect of vesical, urethral, pelvic, or pudendal anesthesia and vesical and urethral mechanical stimulation were studied. Our results suggest that spinalization produces two major types of neurourologic disorders: (1) weakness of detrusor contractor reflexes (vesicovesical and urethrovesical contraction reflexes) and (2) exaggeration of urethral contractor reflexes (urethrourethral contraction reflex, guarding reflex). Secondarily the weakness of detrusor contractions diminishes the efficiency of the urethral reflex relaxation needed for voiding (vesicourethral relaxation reflex). Because of these abnormalities, two main syndromes appear: (1) underactive detrusor function and (2) detrusor sphincter dyssynergia. Isolated peripheral manipulations of the bladder or urethra do not improve micturition: (1) increase in detrusor contraction strength induces detrusor sphincter dyssynergia, and (2) relaxation of the external sphincter facilitates voiding, but urinary retention persists. It is proposed that spinalization produces a central micturitional dysreflexia responsible for the peripheral dysfunction, and treatment must be oriented toward the central dysreflexia rather than the peripheral dysfunction.

Circumferential adjustment of the position of a two-dimensional ultrasound (US) probe around the neck has been recommended as a strategy for reducing the potential for unintentional common carotid artery puncture during internal jugular venous (IJV) cannulation. We obtained multiple high-resolution US images bilaterally from the necks of 107 adult subjects and analyzed these to determine the degree to which this strategy permits identification of a pathway from the skin to the IJV that minimizes venoarterial overlap while maximizing venous target (angular) width. The method consistently permitted identification of an approach to the IJV superior to that obtainable with any one of four popular surface anatomy-based ("blind") approaches and was even more powerful if used in concert with a US-guided 1) adjustment of the degree of head rotation, 2) choice between a high and low approach, and 3) choice between the right and left IJV. Use of a high-resolution US imaging device also permitted identification of the precise boundaries of additional cervical anatomic structures (nontarget vessels, lymph nodes, and the thyroid gland) potentially relevant to selection of an optimal approach to the IJV.