Ectopic uterine tissue as a chronic pain generator.

While chronic pain is a main symptom in endometriosis, the underlying mechanisms and effective therapy remain elusive. We developed an animal model enabling the exploration of ectopic endometrium as a source of endometriosis pain. Rats were surgically implanted with autologous uterus in the gastrocnemius muscle. Within two weeks, visual inspection revealed the presence of a reddish-brown fluid-filled cystic structure at the implant site. Histology demonstrated cystic glandular structures with stromal invasion of the muscle. Immunohistochemical studies of these lesions revealed the presence of markers for nociceptor nerve fibers and neuronal sprouting. Fourteen days after surgery rats exhibited persistent mechanical hyperalgesia at the site of the ectopic endometrial lesion. Intralesional, but not contralateral, injection of progesterone was dose-dependently antihyperalgesic. Systemic administration of leuprolide also produced antihyperalgesia. In vivo electrophysiological recordings from sensory neurons innervating the lesion revealed a significant increase in their response to sustained mechanical stimulation. These results are consistent with clinical and pathological findings observed in patients with endometriosis, compatible with the ectopic endometrium as a source of pain. This model of endometriosis allows mechanistic exploration at the lesion site facilitating our understanding of endometriosis pain.

GDNF induces mechanical hyperalgesia in muscle by reducing I(BK) in isolectin B4-positive nociceptors.

We have assessed the mechanism underlying glial cell-derived neurotrophic factor (GDNF)-induced mechanical hyperalgesia in the gastrocnemius muscle, using patch clamp electrophysiology, in vivo electrophysiology and behavioral studies. Cultured isolectin B4-positive (IB4+) dorsal root ganglion neurons that innervated this muscle were held under current clamp; the majority developed an increase in action potential duration (a factor of increase of 2.29±0.24, compared to 1.13±0.17 in control, P<0.01) in response to GDNF (200 ng/ml) by 15 min after application. They also demonstrated a depolarization of resting membrane potential, but without significant changes in rheobase, action potential peak, or after-hyperpolarization. Large-conductance voltage- and calcium-activated potassium (BK) channels, which have recently been shown to play a role in the repolarization of IB4+ nociceptors, were inhibited under voltage clamp, as indicated by a significant reduction in the iberiotoxin-sensitive current. In vivo single-fiber recording from muscle afferents revealed that injection of iberiotoxin into their peripheral nociceptive field caused an increase in nociceptor firing in response to a 60s suprathreshold stimulus (an increase from 392.2±119.8 spikes to 596.1±170.8 spikes, P<0.05). This was observed in the absence of changes in the mechanical threshold. Finally, injection of iberiotoxin into the gastrocnemius muscle produced dose-dependent mechanical hyperalgesia. These data support the suggestion that GDNF induces nociceptor sensitization and mechanical hyperalgesia, at least in part, by inhibiting BK current in IB4+ nociceptors.

The metal-ion-dependent adhesion site in the Von Willebrand factor-A domain of alpha2delta subunits is key to trafficking voltage-gated Ca2+ channels.

All auxiliary alpha2delta subunits of voltage-gated Ca2+ (Ca(V)) channels contain an extracellular Von Willebrand factor-A (VWA) domain that, in alpha2delta-1 and -2, has a perfect metal-ion-dependent adhesion site (MIDAS). Modeling of the alpha2delta-2 VWA domain shows it to be highly likely to bind a divalent cation. Mutating the three key MIDAS residues responsible for divalent cation binding resulted in a MIDAS mutant alpha2delta-2 subunit that was still processed and trafficked normally when it was expressed alone. However, unlike WT alpha2delta-2, the MIDAS mutant alpha2delta-2 subunit did not enhance and, in some cases, further diminished Ca(V)1.2, -2.1, and -2.2 currents coexpressed with beta1b by using either Ba2+ or Na+ as a permeant ion. Furthermore, expression of the MIDAS mutant alpha2delta-2 reduced surface expression and strongly increased the perinuclear retention of Ca(V)alpha1 subunits at the earliest time at which expression was observed in both Cos-7 and NG108-15 cells. Despite the presence of endogenous alpha2delta subunits, heterologous expression of alpha2delta-2 in differentiated NG108-15 cells further enhanced the endogenous high-threshold Ca2+ currents, whereas this enhancement was prevented by the MIDAS mutations. Our results indicate that alpha2delta subunits normally interact with the Ca(V)alpha1 subunit early in their maturation, before the appearance of functional plasma membrane channels, and an intact MIDAS motif in the alpha2delta subunit is required to promote trafficking of the alpha1 subunit to the plasma membrane by an integrin-like switch. This finding provides evidence for a primary role of a VWA domain in intracellular trafficking of a multimeric complex, in contrast to the more usual roles in binding extracellular ligands in other exofacial VWA domains.

Office laboratory diagnosis of vaginitis. Clinician-performed tests compared with a rapid nucleic acid hybridization test.

BACKGROUND: The traditional diagnosis of vaginitis incorporates patient symptoms, clinical findings observed during vaginal examination, and laboratory analysis of vaginal fluid. The purpose of this study was to evaluate routine clinician-performed office laboratory diagnostic techniques for women with abnormal vaginal symptoms, and to compare these results with those obtained by a DNA hybridization test for Trichomonas vaginalis, Gardnerella vaginalis, and Candida species. METHODS: The study included 501 symptomatic women who were between the ages of 14 and 67 years. Three vaginal specimens were obtained for saline wet mount, potassium hydroxide (KOH) prep, amine "sniff", pH, and nucleic acid hybridization (T vaginalis, G vaginalis, and Candida sp) tests. Clinicians and medical technicians independently evaluated the wet mount, KOH prep, amine, and pH tests. A medical technician processed the DNA tests according to manufacturer's protocol. RESULTS: Of 499 subjects for whom complete data were available, vulvovaginal candidiasis was diagnosed in 20.0%, vaginal trichomoniasis in 7.4%, and bacterial vaginosis in 52.1%. Fourteen percent of subjects had multiple vaginal infections. The sensitivity and specificity of clinician microscopically diagnosed vulvovaginal candidiasis, vaginal trichomoniasis, and bacterial vaginosis were 39.6% and 90.4%, 75.0% and 96.6%, and 76.5% and 70.8%, respectively. The sensitivity and specificity of the DNA probe diagnosis of the same types of vaginitis were 75.0% and 95.7%, 86.5% and 98.5%, and 95.4% and 60.7%, respectively. When only women with multiple vaginal infections were considered, the percentages of correct clinician diagnoses for vulvovaginal candidiasis, vaginal trichomoniasis, and bacterial vaginosis were 49.3%, 83.6%, and 59.7%, respectively. For the DNA probe test, the percentages of correct diagnoses were 72.9%, 92.9%, and 90.0%, respectively. CONCLUSIONS: Primary care clinicians demonstrated a high specificity but low sensitivity when identifying vaginal trichomoniasis and vulvovaginal candidiasis by microscopic techniques. Correct microscopic diagnosis of bacterial vaginosis was even more difficult for clinicians, as was the diagnosis of multiple vaginal infections. Clinicians were not as accurate as the DNA probe test in diagnosing vaginal infections. Clinicians need more education in the laboratory diagnosis of vaginitis. Clinicians should carefully scrutinize each microscopic slide, systematically examine the slide for each type of vaginitis, and consider specimen pH and the presence of leukocytes, Lactobacillus organisms, or amine odor as additional clues to infection.

Treatment of bacterial vaginosis: a comparison of oral metronidazole, metronidazole vaginal gel, and clindamycin vaginal cream.

BACKGROUND: Treatment options for bacterial vaginosis are numerous. The purpose of this study was to compare the efficacy of oral metronidazole, metronidazole vaginal gel, and clindamycin vaginal cream for the treatment of bacterial vaginosis using traditional clinical and laboratory methods, as well as a new DNA probe test. We also determined the percentage of patients receiving each treatment who developed posttreatment vaginal candidiasis, a potential complication of treating bacterial vaginosis. METHODS: One hundred one women in whom bacterial vaginosis was diagnosed by standard criteria were randomly assigned to receive: oral metronidazole 500 mg twice daily for 1 week, 0.75% metronidazole vaginal gel 5 g twice daily for 5 days, or 2% clindamycin vaginal cream 5 g once daily for 7 days. Women with coexisting vulvovaginal candidiasis or vaginal trichomoniasis were excluded. Tests of cure by vaginal saline wet prep and potassium hydroxide microscopic examinations, Gram's stain, pH and DNA probe tests for Gardnerella vaginalis and Candida species were scheduled 7 to 14 days following treatment. RESULTS: There were no statistically significant differences in cure rates for oral metronidazole (84.2%), metronidazole vaginal gel (75.0%), or clindamycin vaginal cream (86.2%) (chi 2 = 1.204, df = 2, P = .548) using traditional clinical and laboratory criteria. Cure rates were lower based on DNA testing, indicating that Gardnerella vaginalis may remain after a clinical cure. This would explain cases of recurrent disease. Posttreatment vulvovaginal candidiasis was experienced by 12.5% of subjects treated with oral metronidazole, 14.8% of subjects treated with clindamycin vaginal cream, and 30.4% of subjects treated with metronidazole vaginal gel (chi 2 = 2.607, df = 2, P = .272). CONCLUSIONS: Oral metronidazole, metronidazole vaginal gel, and clindamycin vaginal cream achieved nearly equivalent cure rates for the treatment of bacterial vaginosis. Patients treated with these agents experienced similar rates of posttreatment vulvovaginal candidiasis, but those using the intravaginal products reported being more satisfied with the treatment.

Physician views on frequent medical use: patient beliefs and demographic and diagnostic correlates.

BACKGROUND: Health care "misusers" have long been identified as hypochondriacs, problem patients, "worried well" patients, and persistent somatizers. The stereotypical pattern includes persistent pursuit of medical care, a wide range of chronic symptoms, and underlying depression. The purpose of this study was to gather prevalence data on individual patients and to examine patient variables that influence the use of medical services by this population. METHODS: Frequent health care users in an HMO were classified by their primary care providers in terms of appropriate use (36%), moderate misuse (inappropriate or psychosomatic, 27%), and extreme misuse (both inappropriate and psychosomatic, 37%) categories. Utilization and diagnostic data were compared using analysis of variance or chi-square tests. RESULTS: All patients rated as misusers to any degree represented only 17.1% of the population, yet accounted for 42.7% of the visits. Extreme misusers accounted for 25% of visits and 10% of the population. Compared with frequent appropriate users, misusers had a greater belief in their own responsibility for health (internal health locus of control), expressed more concern about their mental health, and rated psychological symptoms as more serious. In addition, extreme misusers were younger, reported more symptoms, and believed less in the physician's control of their health. Misusers sought care for minor symptoms or for complaints that were not diagnosed as disease. CONCLUSIONS: Misuse as a physician-perceived variable is highly prevalent. Misusers differ in their beliefs about health care as well as in the kinds and severity of problems for which care is sought. Physicians need to be sensitive to the interpersonal nature of this problem so as not to discourage preventive medical use, and to recognize the value of these visits to the "worried well" population.