80 likes | 228 Views
Electrical Inhibition (EI) Of Human Preterm Uterine Contractions: Just Another Pretty Smooth Muscle! Jeffrey Karsdon, M.D.; Neonatology, Lambda Max, Baldwin, NY, USA Graham G. Ashmead, M.D.; OBGYN, St. Luke’s-Roosevelt Hospital Center, New York, NY, USA
E N D
Electrical Inhibition (EI) Of Human Preterm Uterine Contractions: Just Another Pretty Smooth Muscle! Jeffrey Karsdon, M.D.; Neonatology, Lambda Max, Baldwin, NY, USA Graham G. Ashmead, M.D.; OBGYN, St. Luke’s-Roosevelt Hospital Center, New York, NY, USA Manal El Daouk, M.D.; OBGYN, St. Luke’s-Roosevelt Hospital Center, New York, NY, USA William M. Huang, M.D.; OBGYN, New York Downtown Hospital, New York, NY, USA
Hypothesis: Electrical pacemaker will decrease smooth muscle contractions or tone. Electroceutical therapy or Electrical Inhibition (EI). • Background: Smooth muscles produce contractions or tone e.g. preterm uterine contractions or vascular tone (blood flow). • Pharmaceuticals do not control smooth muscles efficiently and have many side effects. • EI of electrical (EMG) activity does efficiently control smooth muscle contractions or tone with few side effects: • Human uterine smooth muscle, increased spontaneous EMG activity precedes contractions (top, contractions; bottom, EMG). • Human corpus cavernosum smooth muscle, decreased spontaneous EMG activity (arrows) decreased smooth muscle tone allowing increased blood flow (top, blood flow; bottom, EMG). • Rat uterine smooth muscle, electrical inhibition (EI) of spontaneous EMG (arrows) decreases contractions and tone (top, contractions; bottom, EMG). A Wolfs et. al. Obstet Gynecol. 1971;37:241-246 B Jiang et. al. J Urol. 2005;174:1917-1920 C Karsdon (unpublished)
Method: EI pacemaker/generator sends the electrical current to an electrode catheter that is placed next to the smooth muscle of the cervix. • EI generator: • Power cable • Step down transformer • Power connector cable • EI generator with connector • Electrode catheter connector cable • Electrode catheter • B. Electrodes directly onto the uterus. • C. Transvaginal electrode catheter (TVC) placed into the vaginal canal with the tip next to the smooth muscle of the rat cervix. • D. TVC placed into the vaginal canal with the tip next to the smooth muscle of the human cervix (arrow). A. 1 2 3 4 5 6 D. C. B.
Method: Outcomes • Uterine smooth muscle contraction • or tone measurements: • rabbit and rat, intrauterine pressure • (IUP); • rat, EMG and pup birth intervals (BI); • human, uterine contractions (tocodynomometer/toco) and fetal • heart rate (FHR) for side effects.
Results: • EI in the rat decreased EMG activity (spectrum analysis): • amplitude • spike frequency • area-under-the-curve or power • EI decreased the EMG dependent smooth muscle tone and contractions, both amplitude and frequency, in all species studied; • top panel: rabbit, EI (arrow up) decreased IUP only in the study horn and control horn not affected; • middle panel: rat, EI (arrow) decreased the EMG (bottom) and IUP (top); • bottom panel: human, EI (arrows) subjectively toco (bottom) was decreasedj and had no effect on FHR (top) or maternal heart rate (not shown). • Note! decreased resting uterine smooth muscle tone for several minutes after only 2 seconds (RMS) of EI (B, solid lines in middle and bottom panels) even without EI applied. A. Karsdon et. al. Am J Obstet Gynecol. 2005; 193, 1986-1993 B.
Results:EI increased smooth muscle relaxation (table): 1) EI decreased rabbit IUP. 2) EI, both directly and by TVC, increased rat pup BI by 1941% and 628% respectively. 3) EI in women decreased toco contraction frequency or increased peak-to-peak (P-P) interval time. Mechanism: EI is thought to: 1) hyperpolarize the cell membrane; 2) resulting in decreased membrane depolarization; 3) thus decreased electrical activity; 4) producing decreased smooth muscle contractions or tone. X X X DECREASED TONE
Conclusions: • Smooth muscle contractions/tone are the result of EMG activity • Decreased EMG activity results in decreased smooth muscle contractions/tone • Decreased vascular smooth muscle tone is associated with increased blood flow • Electrical Inhibition (EI) decreases EMG activity • EI is localized unlike pharmaceuticals and may hyperpolarize the cell membrane • EI decreased (uterine) smooth muscle contractions/tone in animals and humans • EI may have a use in decreasing human smooth muscle contractions/tone: • uterine contractions of preterm births; • neonatal pathologies e.g. persistent pulmonary hypertension • Contact: Dr. Jeffrey Karsdon, M.D. • Email: JK_MD@yahoo.com