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Biomedical subjects

M Monga

Publications and source records attributed to M Monga.

At least 91 records · Page 5Linked to original sources

Gunshot wounds to the male genitalia.

Fifty consecutive cases of gunshot wounds to the male external genitalia were treated by the Tulane University Urology Service at the Medical Center of Louisiana in New Orleans. Fifty percent of the patients had significant associated injuries. Eight anterior urethral injuries were identified, all by retrograde urethrography. Five of 17 testicular injuries were salvaged with conservative operative technique. Review of this series suggests that good functional integrity of the male genitalia after gunshot injury can be maintained by following a strict diagnostic and therapeutic regimen.

Adolescent↗

Posttraumatic high flow internal pudendal artery-urethral fistula.

A case of posttraumatic fistula of the internal pudendal artery-urethra is reported. The patient was referred with prolonged pulsatile gross hematuria requiring multiple blood transfusions after a motor vehicle accident. Associated injuries included a comminuted pubic ramus fracture. Initial uroradiographic evaluations did not identify the site of origin of hematuria but eventually selective angiography allowed diagnosis. Selective arterial embolization of the internal pudendal artery provided definitive treatment.

Adult↗

Relaxin stimulates myometrial calcium-activated potassium channel activity via protein kinase A.

Relaxin, a hormone that is elevated during pregnancy, can suppress myometrial contractile activity. Ca(2+)-activated K+ channels (KCa) play a role in the modulation of uterine contractions and myometrial Ca2+ homeostasis and have been implicated in the control of smooth muscle excitability. We now show that relaxin stimulates KCa channels in cell-attached patches in a cell line derived from term pregnant human myometrium. This effect was prevented by the protein kinase A (PKA) antagonist, the Rp diastereomer of adenosine 3',5'-cyclic monophosphothioate (Rp-cAMPS). After patch excision, the channel was activated by PKA and inhibited by alkaline phosphatase. These data suggest that relaxin may promote myometrial quiescence in part by stimulation of KCa channels via a PKA-mediated mechanism.

Calcium↗

Modified pubovaginal sling and Martius graft for repair of the recurrent vesicovaginal fistula involving the internal urinary sphincter.

A modified Martius graft interposition flap was used in conjunction with the modified pubovaginal sling bladder suspension to treat a recurrent vesicovaginal fistula involving the proximal urethra and bladder neck. The patient recovered with no incontinence, voiding dysfunction or dyspareunia. Incontinence should be anticipated with vesicovaginal fistulas involving the internal sphincter and repair should be tailored to include an organic suburethral sling.

Adult↗

The forgotten indwelling ureteral stent: a urological dilemma.

Ureteral stents are an integral part of urological practice. However, stents that migrate, fragment or are forgotten pose a management and legal dilemma. Our series consists of 31 patients, 22 with forgotten stents that were left indwelling for more than 6 months (mean 22.7) and 9 migrated stents. Of the forgotten stents 15 (68%) were calcified, 10 (45%) were fragmented, and 3 (14%) were calcified and fragmented. Procedures to render the patient stent-free were ureteroscopy in 16 (52%), percutaneous nephroscopy in 8 (26%), cystoscopic electrohydraulic lithotripsy in 6 (19%), extracorporeal shock wave lithotripsy in 10 (32%), open cysto-litholapaxy in 1 (3%) and simple nephrectomy in 1 (3%). Multiple procedures were required in 6 patients (19%). Management of such complicated ureteral stents requires a multimodal therapeutic approach incorporating the latest in extracorporeal shock wave lithotripsy and endourological techniques. These patients are at increased risk for loss of renal function. A computerized tracking registry of ureteral stents may help prevent this urological travesty.

Adult↗

Mechanisms regulating oxytocin receptor coupling to phospholipase C in rat and human myometrium.

Oxytocin increases myometrial intracellular free calcium by promotion of calcium entry and release of calcium from intracellular stores. Calcium release from intracellular stores is secondary to an increase in phosphoinositide (PI) turnover and generation of IP3. We have explored the biochemical basis for the coupling of oxytocin (OT) to phospholipase C (PLC). Rat myometrial membranes contain PLC beta, gamma, and delta isoforms as well as the GTP-binding proteins G alpha(q) and G alpha(11). Oxytocin stimulates both GTPase and PLC activity in rat and human myometrial membranes. These data and available structural information suggest that the oxytocin receptor couples to PLC through a GTP-binding protein. In support of this hypothesis, an antibody generated against the specific C-terminal region of G alpha(q) and G alpha(11) inhibits both the oxytocin-stimulated GTPase and PLC activities. This inhibition is reversed by neutralization of the antibody with the antigenic peptide. The data indicate that the oxytocin receptor couples to PLC, presumably of the beta subclass, via interaction with proteins of the G alpha(q/11) subclass. In the nonpregnant, estrogen-primed rat, the stimulation of PI turnover by oxytocin is inhibited by the hormone relaxin and by pertussis toxin. The effects of both of these agents are mediated by the action of cAMP-dependent protein kinase. In plasma membranes, GTP-stimulated PLC activity can also be inhibited by treatment with protein kinase A. These data suggest that cAMP-dependent phosphorylation at a step involving GTP-binding protein/PLC coupling can exert a negative effect on the stimulation of IP3 formation by oxytocin and thereby affect contraction/relaxation in the myometrium.

Animals↗

Cocaine alters placental production of thromboxane and prostacyclin.

OBJECTIVE: The objective of this study was to test the hypothesis that cocaine alters placental prostaglandin production in vitro. STUDY DESIGN: Placentas were obtained from healthy women (n = 6) after normal vaginal delivery at term. Placental explants (300 mg) were incubated in duplicate at 37 degrees C in the presence of 0, 30, 300, or 3000 ng/ml cocaine. Thromboxane and prostacyclin production was measured by radioimmunoassay of their stable metabolites (thromboxane B2 and 6-keto-prostaglandin F1 alpha) at 0, 0.5, 1.0, 1.5, 2, 4, 8, and 12 hours. Analysis of variance with Newman-Keuls test was used for statistical analysis. RESULTS: Cocaine increased thromboxane production in a dose-dependent manner (p < 0.001) and decreased prostacyclin production (p < 0.05). Cocaine increased the ratio of thromboxane/prostacyclin production (p < 0.05). CONCLUSION: Cocaine alters the placental production of prostaglandins in vitro, favoring thromboxane production, which may cause vasoconstriction and decrease uteroplacental blood flow.

6-Ketoprostaglandin F1 alpha↗

Penile erection in the primate: induction with nitric-oxide donors.

The primate model has been used for investigations on the physiology and pharmacology of erection. Recent in vitro investigations indicate that nitric oxide acts as the mediator of penile erection, but in vivo primate studies are needed to corroborate these findings. Penile erections were induced in a primate model using intracavernosal injections of nitric oxide donors s-nitrocysteine (NO-CYS) and sodium nitroprusside (SNP), and acetylcholine (ACh) which stimulates the formation of nitric oxide. Penile length and intracavernosal pressures following agonist injection were compared with baseline (flaccid) and control erections (elicited by injection of a papaverine/phentolamine/PGE1 standard mixture). Dose-response curves for each drug were determined with respect to maximal intracavernosal pressure, duration of effect and penile length, and systemic arterial pressure was monitored. All three agents induced erections, with dose-dependent increases in cavernosal pressure and penile length. The maximal cavernosal pressure attained was similar for all three agents, but the duration of action was significantly shorter with ACh (p < .05). Injection of L-nitro-arginine-methyl-ester (L-NAME), a nitric oxide synthase inhibitor, before injection of the nitric oxide donor shortened the duration of effect but did not alter maximal cavernosal pressure or penile length attained. Although systemic hypotension was induced by each agent, digital compression at the base of the penis at the time of injection prevented such changes. These results suggest that the primate is a useful model to evaluate the action of substances that induce or inhibit penile erection. The findings provide support for the hypothesis that nitric oxide is a mediator of penile erection and that nitric oxide donors may be useful in the treatment of erectile dysfunction.

Acetylcholine↗

Ilioinguinal nerve entrapment following needle bladder suspension procedures.

Ilioinguinal nerve entrapment is a documented complication of inguinal herniorrhaphy, inguinal lymph node dissection, and appendectomy. This article reports two clinical histories to illustrate the diagnosis and management, and outlines prevention of ilioinguinal nerve entrapment as a complication of needle suspension procedures for stress urinary incontinence.

Adult↗

The acute effect of cocaine exposure on pregnant human myometrial contractile activity.

OBJECTIVE: The objective of this study was to test the hypothesis that cocaine acutely increases contractile activity in isolated pregnant human myometrium. STUDY DESIGN: Myometrial samples were obtained from the lower uterine segment at elective cesarean section from five women at term who were not in labor and who had no perinatal risk factors. Myometrial strips were suspended in contractile buffer, and isometric contractions were measured. Frequency, amplitude, duration, and integrated area (mean +/- SE) were compared before and after the addition of cocaine (10(-6) to 10(-4) mol/L) by means of analysis of variance and Duncan's multiple range test. RESULTS: Contraction duration, expressed relative to control, increased acutely after addition of cocaine (10(-5) mol/L, 2.0 +/- 0.29; 10(-4) mol/L, 2.8 +/- 0.64) (p < 0.001). Integrated area of contractions also increased relative to control (10(-6) mol/L, 1.6 +/- 0.18, p < 0.05; 10(-5) mol/L, 2.4 +/- 0.16 and 10(-4) mol/L, 3.5 +/- 0.23, p < 0.001). These effects were dose dependent. CONCLUSION: Cocaine acutely increases contractile activity in myometrium isolated from pregnant women.

Cocaine↗

Endotoxin, interleukin-1 beta, interleukin-6, or tumor necrosis factor-alpha do not acutely stimulate isolated murine myometrial contractile activity.

OBJECTIVES: Endotoxin, interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha have been implicated in the pathogenesis of preterm labor, but their acute effect on myometrial contractile activity is unknown. The objective of this study was to determine their effect on isolated pregnant murine myometrial contractile activity. STUDY DESIGN: Isometric contractions were measured in myometrium isolated from pregnancy day 18 Swiss-Webster mice. Frequency, duration, amplitude, and integrated area were compared before and after the addition of endotoxin (10(3) and 10(4) ng/ml) (n = 6), interleukin-1 beta (10 and 10 ng/ml) (n = 6), interleukin-6 (1 and 10 ng/ml) (n = 6), and tumor necrosis factor-alpha (1 and 10 ng/ml) (n = 6). Results were analyzed with the Wilcoxon rank-sum test. RESULTS: The addition of endotoxin, interleukin-1 beta, interleukin-6, or tumor necrosis factor-alpha did not result in a change in the contractile activity of isolated pregnant murine myometrium compared with control. CONCLUSION: Endotoxin, interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha do not acutely increase isolated murine myometrial contractile activity.

Animals↗

Cocaine acutely increases rat myometrial contractile activity by mechanisms other than potentiation of adrenergic pathways.

OBJECTIVE: We hypothesized that cocaine acutely increases contractile activity in isolated rat myometrium and that this effect is solely caused by potentiation of adrenergic pathways. STUDY DESIGN: Isometric contractions were measured in myometrium isolated from virgin and day-18 pregnant Sprague-Dawley rats. Frequency, duration, amplitude, and integrated area were compared before and after the addition of cocaine (10(-6) to 10(-4) mol/L) by means of analysis of variance and Duncan's multiple-range test. The effects of alpha-adrenergic receptor antagonists (prazosin 10(-6) mol/L and yohimbine 10(-6) mol/L) and beta-adrenergic receptor antagonist (DL-propranolol 2 x 10(-6) mol/L) were assessed. RESULTS: Contraction duration, expressed relative to control, increased acutely after cocaine (10(-5) mol/L) administration in pregnant (1.70 +/- 0.20) and nonpregnant (1.36 +/- 0.24) myometrium (mean +/- SE, p < 0.05), as did integrated area (pregnant 3.47 +/- 0.97, nonpregnant 2.48 +/- 0.66) (mean +/- SE, p < 0.05). These effects were not completely inhibited by adrenergic blockade. CONCLUSION: Cocaine acutely increases the duration and integrated area of spontaneous contractions in isolated rat myometrium by mechanisms not completely explained by inhibition of catecholamine reuptake and potentiation of adrenergic pathways.

Animals↗

Disseminated herpes zoster in a pregnant woman positive for human immunodeficiency virus.

We report a case of disseminated herpes zoster in a pregnant patient positive for the human immunodeficiency virus (HIV). Disseminated zoster was the first manifestation of HIV infection in this patient. In HIV-positive patients, zoster may be complicated by cutaneous dissemination, visceral involvement, and death. Intravenous acyclovir may prevent serious sequelae in both mother and fetus.

AIDS-Related Opportunistic Infections↗

Calcium-activated K+ channels as modulators of human myometrial contractile activity.

The role of Ca(2+)-activated potassium (KCa) channels in the regulation of membrane potential, intracellular free calcium ([Ca2+]i) and contraction was investigated in uterine smooth muscle and myometrial cells. In an immortalized human myometrial cell line, oxytocin increased [Ca2+]i and [3H]inositol phosphate formation. Relaxin attenuated the oxytocin-induced increase in [Ca2+]i. In cell-attached patches, membrane depolarization activated a large-conductance KCa channel (179 +/- 4 pS). Iberiotoxin (IbTX), a potent blocker of "maxi" KCa channels (A. Galvez, G. Gimenez-Gallego, J. P. Reuben, L. Roy-Contanciin, P. Feigenbaum, G. J. Kaczorowski, and M. L. Garcia. J. Biol. Chem. 265: 11083-11090, 1990) produced long closed events (approximately 6 min) in these channels. In agreement with this blockage, IbTX depolarized the cells by 9.8 +/- 2.8 mV and caused a dose-dependent increase in [Ca2+]i with a half-maximal effective concentration of 0.79 nM. IbTX also caused phasic contractions in human myometrial strips and increased both the frequency and force of spontaneous contractions in estrogen-primed rat myometrial strips. Moreover, myometrial contractility was also affected by 1 mM tetraethylammonium, a concentration that blocks uterine smooth muscle KCa channels when applied to the extracellular side (G. J. Perez, L. Toro, S. D. Erulkar, and E. Stefani. Am. J. Obstet. Gynecol. 168: 652-660, 1993). These results strongly suggest that the large conductance KCa channels may actively participate in the control of human myometrial cell membrane potential and [Ca2+].

Calcium↗

Single-dose ampicillin prophylaxis does not eradicate enterococcus from the lower genital tract.

OBJECTIVES: To determine the carriage rate of enterococcus in the lower genital tract of women having a cesarean delivery and to determine whether a single 2-g intraoperative dose of ampicillin eradicates enterococcus from the lower genital tract. METHODS: Lower genital tract cultures were taken in 84 women who were in labor or had ruptured membranes and who were about to have an indicated cesarean delivery. The subjects were randomized to receive either a single 2-g dose of ampicillin or a cephalosporin as prophylaxis. Cultures were repeated 24 hours postpartum. RESULTS: Enterococcus was isolated preoperatively in 33 subjects (39.3%) and postoperatively in 36 (42.9%). The enterococcus was eradicated in five of 17 women (29.5%) who received ampicillin. CONCLUSION: These results suggest that a single 2-g dose of ampicillin does not eradicate enterococcus from the lower genital tract.

Adult↗