PubMed Health⌕ Search

Biomedical subjects

R Khouri

Publications and source records attributed to R Khouri.

16 recordsLinked to original sources
PubMed1996

Correlation between time-domain measures of heart rate variability and scatterplots in postinfarction patients.

Heart rate variability (HRV) is usually measured in time or frequency domains. Beat-to-beat variability, which cannot be assessed by frequency-domain analysis, and can only be assessed globally by time-domain analysis, provides information concerning the nonlinear behavior of heart rate. This beat-to-beat variability can be displayed on scatterplots, where each RR interval is plotted against the preceding RR interval. However, the relationship between scatterplots and other measures of HRV is unknown. We studied the correlations between time-domain measures and scatterplot length, width, and area in 50 postinfarction patients. Scatterplot length and width were measured after printing. Scatterplot area was calculated from length and width, assimilating the plot to an ellipse. Long-term variability indexes (SDNN and SDANN) were strongly correlated with scatterplot length (r > 0.9, P < 0.0001), and short-term variability parameters (pNN50 and variability index) with scatterplot width (r > 0.9; P < 0.0001). Scatterplots are, therefore, a simple way of providing information concerning long- and short-term HRV. Furthermore, measurement of scatterplot width at different given RR intervals could be an approach to the evaluation of short-term HRV for different heart rates. This could provide a simple way of assessing cardiac parasympathetic modulation at different heart rates.

Adult↗
PubMed1994

The use of prefabricated fascial flaps for lining of the oral and nasal cavities.

Twelve temporoparietal fascial flaps were prefabricated to line the oral and/or nasal cavities in 10 patients. Bilateral flaps were used both in a patient suffering from lye ingestion and in a patient undergoing bilateral lip reconstruction. All reconstructions were performed in two stages separated by 3 to 4 weeks. The first stage involved creation of an epithelial lining by placing a non-hair-bearing skin graft over the temporoparietal fascia. The second stage raised the fascial flaps as vascular islands and transferred them as either pedicled or free flaps. All 12 flaps survived and improved function for the patients involved. Although all possible applications for this flap have not been explored fully, there appears to be great potential for the use of this procedure in refined reconstructions of moderately sized intraoral and nasal defects.

Adult↗
PubMed1989

Cutaneous blood supply of the penis.

Twelve male cadaver specimens were injected with a latex solution to define the cutaneous blood supply of the penis. The cutaneous blood supply of the penile shaft is derived solely from a pair of axial arteries running in the dartos layer. Additional deep perforating arteries from the dorsal penile artery and corporal vessels supply the glans and subcoronal region. An understanding of this anatomy allows one to develop safely a variety of penile skin flaps for difficult reconstructive problems.

Aged↗
PubMed1989

Distraction lengthening for the congenitally short metatarsal: a case report.

Distraction lengthening has gained wide acceptance in general orthopedics and in upper extremity reconstructions. The application of this technique to the foot is presented. The congenitally short fourth metatarsal of a 16-yr-old girl was successfully lengthened by a two-stage procedure. At the first stage, an open diaphyseal osteotomy was performed and the distraction apparatus was secured. Over the ensuing 5 weeks, 36 mm of distraction was achieved. At the second stage, the distracted gap was filled with a fibular bone graft. Following uncomplicated healing, there was no gait, intrinsic muscle, or tendon abnormalities. Metatarsal distraction lengthening can be safely accomplished provided there is good bone stock, adequate soft tissue, and a cooperative patient.

Adolescent↗
PubMed1983

Ascorbic acid is an endogenous cytosolic inhibitor of ATP-supported rat liver mitochondrial calcium transport.

ATP-supported but not Site I or Site II respiratory chain-linked 45Ca2+ transport into isolated rat liver mitochondria is profoundly inhibited by a small molecule present in the cytosolic fraction. This inhibitor was purified and shown to be identical with ascorbic acid in a number of chemical properties, cytosolic abundance, susceptibility to ascorbate oxidase, and to agents that otherwise block the effect of authentic ascorbic acid. Experiments with a variety of free radical scavengers and glutathione indicated that ascorbate inhibition of calcium transport is mediated through a 1-electron-free radical mechanism rather than a conventional 2-electron reaction. Calcium transport mechanisms may, therefore, be a target in the pathophysiology of disease processes that influence the intracellular ratios and levels of ascorbate and physiological radical scavengers.

Adenosine Triphosphate↗