Accuracy evaluation of a two-wire technique for osteotomy positioning in the tibial plateau levelling procedure.

OBJECTIVE: To evaluate a tibial plateau levelling osteotomy (TPLO) saw blade positioning technique and to retrospectively evaluate the accuracy of the osteotomy position. METHOD: Preoperative and postoperative radiographs of 72 cases that had a TPLO surgery using a two-wire technique were reviewed. Three measurements (A1, B1, C1) were obtained in preoperative planning using a computer template system (Orthoview Vet) which mapped the intended osteotomy position. The postoperative radiographs were analysed to determine the variability of these three measurements (A2, B2, C2) and therefore the accuracy of the osteotomy. RESULTS: On average the least variable measurement was B2 (5%) followed by C2 (7%) and then A2 (13%). The maximum mean difference between the intended position and achieved position was 1.5 mm. CLINICAL SIGNIFICANCE: Despite there being a significant difference between the intended and the actual position of the osteotomy, the variation between the intended and actual tibial tuberosity width was small (5%). None of the cases suffered a tibial tuberosity fracture, which also supports the clinical value of this technique. Care must be taken to avoid inadvertent cutting of the Kirschner guide wires.

Use of computerized medical records to determine the feasibility of testing for chlamydia without patients seeing a practitioner.

The proportion of clinically important diagnoses in a low-risk, asymptomatic population who use a computer-assisted self-interview (CASI) to assess risk was needed to determine optimal health service delivery. Medical records were retrospectively analysed between July 2008 and June 2009 for risk characteristics and diagnoses. A total of 7733 new patients completed a CASI, of whom 1060 were asymptomatic heterosexuals. From this low-risk group, 26 diagnoses were made on the day of presentation, including 22 cases of genital warts (2.08% [95% confidence interval (CI) 1.22-2.93]), three cases of genital herpes (0.28% [95% CI 0.055-0.82]) and one case of unintended pregnancy (0.094% [95% CI 0.0061-0.52]). Additionally, there were 54 cases of chlamydia detected (5.09% [95% CI 3.77-6.42]). As chlamydia is effectively diagnosed and managed from self-collected samples, patient review is not always required. This study provides evidence for an express testing service for chlamydia to streamline the screening of low-risk, asymptomatic heterosexual patients as identified by CASI without the need to for a traditional face-to-face consultation.

Propagation of a partial incomplete ossification of the humeral condyle in an American cocker spaniel.

A hypoattenuating lesion in the left humeral condyle of an American cocker spaniel consistent with partial incomplete ossification of the humeral condyle was observed on computed tomography. Left forelimb lameness developed over the following three weeks at which time repeat computed tomography examination confirmed propagation of the lesion. Lameness resolved following placement of a transcondylar positional screw, suggesting that lameness was secondary to condylar instability. To the authors' knowledge this is the first report of propagation of an intracondylar lesion in a dog.

Modification of the ventral approach to the caudal cervical spine by resection of the manubrium in a dog.

A five-year-old neutered female Bassett Hound weighing 29 kg was presented with a two-day history of paraparesis. Neurological examination and magnetic resonance imaging confirmed the presence of extruded disc material ventral to the spinal cord, from the C7-T1 intervertebral disc. A ventral slot was performed to decompress the cord. In making the approach to the caudal cervical spine, the cranial aspect of the manubrium of the sternum was resected. This improved the exposure of a region normally difficult to expose via a conventional ventral approach to the cervical spine. The successful performance of the ventral slot procedure was greatly facilitated by this adaptation, which was quick and simple to perform, without any apparent adverse affects to the animal.

What men who have sex with men think about the human papillomavirus vaccine.

This study aimed to ascertain the attitudes of men who have sex with men (MSM) to the human papillomavirus (HPV) vaccine and to determine the age at which MSM would be willing to ask for the HPV vaccine in relation to their age of sexual debut. Of 205 MSM attending the Melbourne Sexual Health Centre between December 2007 and January 2008, 200 (98%; median age 27 years) completed the study questionnaire. Only 30% were aware that there was a vaccine available for protection against infection with certain HPV types. When informed of the increased risk of anal cancer among MSM, 47% of MSM indicated that they would be willing to pay $A450 for the vaccine course. A total of 93% indicated that they would be willing to disclose that they were MSM to a health professional in order to obtain the vaccine for free, but not until a median age of 20 years: 2 years after the median age of sexual debut (18 years) and after a median of 15 sexual partners. If the HPV vaccine is targeted to MSM, the challenge will be for MSM to be vaccinated before they acquire HPV infection.

Perinatal outcomes in inflammatory bowel disease.

OBJECTIVE: To determine whether inflammatory bowel disease (IBD) is associated with increased risk for adverse perinatal outcome. METHODS: A case-control study of 116 singleton pregnancies with IBD compared to 56,398 singleton controls delivered between 1986 and 2001. RESULTS: Patients with IBD were slightly older (32.8 vs. 30.6 years, p < 0.001), more likely to be Caucasian or Asian than Black or Latino (92% vs. 57%, p < 0.001) and have private health insurance (33% vs. 3%, p < 0.001). IBD was associated with an increased risk for labor induction (32% vs. 24%, p = 0.002), chorioamnionitis (7% vs. 3%, p = 0.04) and Cesarean section (32% vs. 22%, p = 0.007), but there were no differences in neonatal outcomes. Subgroup analysis demonstrated an increased risk for low birth weight (LBW) in the ulcerative colitis group vs. the Crohn's disease group (19% vs. 0%, p = 0.002). Patients with prior surgery for IBD had a lower incidence of LBW (0% vs. 12%, p = 0.03). Flares during pregnancy were associated with an increased risk for preterm delivery (27% vs. 8%, p = 0.02) and LBW (32% vs. 3%, p = 0.003). CONCLUSION: IBD was an independent risk factor for Cesarean section but there was no increase in adverse perinatal outcome. Crohn's disease, prior IBD surgery and quiescent disease were associated with a lower risk for LBW.

E2-induced degradation of uterine insulin receptor substrate-2: requirement for an IGF-I-stimulated, proteasome-dependent pathway.

The insulin receptor substrates are docking proteins that bind various receptor tyrosine kinases and signaling proteins. Previous studies have shown that E2 or progesterone can regulate the relative abundance of insulin receptor substrate-1 and -2 in cells and tissues. For instance, uterine insulin receptor substrate-2 was decreased markedly at 24 h after E2 treatment of mice. In the present study we used various in vivo experimental approaches to examine the mechanism by which E2 influences uterine insulin receptor substrate-2 expression. Uterine insulin receptor substrate-2 mRNA levels were diminished after E2 treatment, but this diminution did not account for the total reduction in insulin receptor substrate-2 protein, suggesting that the E2-induced decrease in insulin receptor substrate-2 is not regulated solely at the mRNA level. Cotreatment with progesterone prevented the E2-stimulated reduction in insulin receptor substrate-2 protein at 24 h after hormone exposure. In addition, MG-132 and epoxomicin, inhibitors of proteasomal protease activity, inhibited the E2-induced decrease in uterine insulin receptor substrate-2 protein levels, and this correlated to an increase in uterine protein ubiquitination. Insulin receptor substrate-2 protein was diminished in uteri of E2-treated insulin receptor substrate-1-null mutant mice, but not in E2-treated IGF-I-null mutant mice. Furthermore, E2-induced diminution of uterine insulin receptor substrate-2 protein was only partially inhibited in the presence of wortmannin, a PI3K inhibitor. Collectively, these data suggest that the E2-induced decrease in uterine insulin receptor substrate-2 requires IGF-I signaling, is not dependent solely on insulin receptor substrate-1 and PI3K, and is blocked by progesterone as well as by pharmacological inhibition of proteasomal protease activity. We speculate that the IGF-I-activated IGF-I receptor, in response to E2, directly or indirectly modifies insulin receptor substrate-2, probably through phosphorylation, leading to ubiquitination and subsequent degradation of this docking protein by the proteasome. This degradation could be a regulatory step to inhibit insulin receptor substrate-2-dependent signaling in the uterus.

Pharmacokinetics and pharmacodynamics of recombinant FGF-2 in a phase I trial in coronary artery disease.

Fibroblast growth factor-2 (FGF-2) is a heparin-binding protein capable of inducing angiogenesis in multiple animal models of chronic ischemia. The pharmacokinetics and pharmacodynamics of a single dose of recombinant FGF-2 (rFGF-2) administered by intracoronary or intravenous infusion were evaluated in a Phase I trial in 66 patients with severe coronary artery disease. rFGF-2 displayed biphasic elimination with a mean studywide distribution t1/2 of 21 minutes and a mean apparent terminal elimination t1/2 of 7.6 hours. Systemic exposure to rFGF-2 was comparable following intracoronary or intravenous administration. Peak plasma concentration and area under the concentration-time curve increased proportionally with dose, indicating linear pharmacokinetics over the dose range examined (0.33 to 48.0 micrograms/kg). Greater systemic exposure was observed when heparin was administered closer to rFGF-2 infusion, consistent with slower clearance of heparin/rFGF-2 complexes. Infusion of rFGF-2 was associated with changes in acute hemodynamics. While a clear PK/PD dose-response relationship was not established, a trend toward hypotension and tachycardia with higher rFGF-2 doses was observed.

Diverticulitis with rupture and fatal peritonitis in a Sumatran orangutan (Pongo pygmaeus).

A 30-year-old male Sumatran orangutan (Pongo pygmaeus) presented with signs of depression, lethargy, anorexia, and diarrhea that progressed to acute colic. Exploratory laparotomy revealed fibrinopurulent peritonitis and 50 cm of devitalized small intestine. The surgically resected small intestine contained several mucosal diverticula along the mesenteric attachment; one had ruptured, resulting in peritonitis. Fifteen days after surgery, the orangutan's abdominal incision dehisced. Repeated laparotomy revealed dehiscence of the distal intestinal anastomosis site, as well as extensive adhesions and purulent exudate. The defect was repaired, and the abdomen was extensively irrigated and closed, but the animal died within 24 hours. To our knowledge, this is the first report of diverticulitis in a great ape. Diverticulosis should be considered in the differential diagnosis for great apes that present with signs of depression, lethargy, anorexia, and/or diarrhea.

Safety and efficacy of solvent/detergent-treated antihaemophilic factor with an added 80 degrees C terminal dry heat treatment in patients with haemophilia A.

Plasma-derived factor VIII concentrates remain an important resource for haemophilia A patients. To improve the safety of these preparations, various methods of viral removal and inactivation have been used that are designed to eliminate both enveloped and non-enveloped viruses. There have been rare reports that some viral inactivation processes altered the immunogenicity of some concentrates, leading to the development of factor VIII inhibitors in previously treated haemophilia A patients. This study evaluated the safety, efficacy and lack of neo-antigenicity of a highly purified factor VIII preparation which undergoes both solvent/detergent treatment and final dry heat treatment at 80 degrees C for 72 h. The study included: (i) a single blind, single-dose crossover pharmacokinetic study in 18 previously treated patients, comparing sibling lots of the unheated preparation (Koate(R)-HP) and the heat-treated preparation (Koate(R)-DVI), and (ii) an extended home treatment programme for 36 patients at two haemophilia treatment centres primarily to assess immunogenicity. Clinical parameters were assessed at regular intervals. The results confirm that Koate(R)-HP and Koate(R)-DVI are bioequivalent, and that Koate(R)-DVI is safe and efficacious for treatment of acute bleeding episodes and for surgery. Furthermore, the heat-treated preparation is not associated with the development of inhibitors in previously treated patients.

Comparing ovulation synchronization protocols for artificial insemination in the scimitar-horned oryx (Oryx dammah).

Ovarian response and pregnancy success in scimitar-horned oryx (n=28) were compared, following treatment with two synchronization protocols and fixed-time artificial insemination (AI) with frozen-thawed semen. Each oryx received two injections of 500 microg of prostaglandin-F(2alpha) analogue (PGF(2alpha)-only) 11 days apart, and half received PGF(2alpha) in combination with an intravaginal progesterone-releasing device (CIDR11+PGF(2alpha)). Semen was collected by electroejaculation from anaesthetised adult oryx and cryopreserved. Anaesthetised females were transcervically inseminated 56.0+/-1.1 h (+/-S.E.M.) after PGF(2alpha) injection and/or device withdrawal using 28.0+/-1.5x10(6) motile thawed sperm. Ovarian endocrine response was monitored in 20 females by analysing faecal oestrogen and progesterone metabolites. Periovulatory oestrogen peaks were detected in 19/20 (95%) females after synchronization. There were no between-treatment differences in oestrogen concentrations or peak characteristics (P0.05). Luteal development after synchronization was delayed in half the progesterone treated (CIDR11+PGF(2alpha)) females, and faecal progestin excretion profiles indicated that the ovulatory follicle associated with synchronization either failed to ovulate or to fully lutenise. Pregnancy was diagnosed by ultrasonography and/or rectal palpation and was monitored by faecal progestin excretion. More (P=0. 013) pregnancies resulted from the PGF(2alpha)-only treatment (37.5%, 5/14) than from the CIDR11+PGF(2alpha) treatment (0/14), and four healthy scimitar-horned oryx calves were born, three after gestation intervals of 247 days and one after 249 days.

Subcutaneous atypical mycobacteriosis in captive tiger quolls (Dasyurus maculatus).

From July 1989 to October 1998, 9/37 (24%) adult captive tiger quolls (Dasyurus maculatus) were diagnosed with atypical mycobacterial infection involving the subcutis and skin. Females were more often affected than males (seven females, two males). Grossly, lesions presented as focal thickenings, plaques, and abscesses within the subcutis, often with fistulous tracts. The subcutis and skin overlying cervical and thoracic regions were the primary sites of infection. Cytology of subcutaneous impression smears from all nine affected tiger quolls revealed pyogranulomatous inflammation admixed with several acid-fast bacilli. Histologically, all tiger quolls had nodular to diffuse pyogranulomatous panniculitis and cellulitis. Small numbers of acid-fast bacilli were noted histologically in 7/9 (78%) animals. Skin cultures from seven tiger quolls were positive for one or more different Runyon group IV mycobacteria. The disease described in these tiger quolls is similar to subcutaneous atypical mycobacteriosis of humans and domestic animals.

An abundant TIP expressed in mature highly vacuolated cells.

Aquaporins are water channel proteins found in vacuolar membranes and plasma membranes, and belong to the major intrinsic protein (MIP) family of proteins. In the present study, we purified a 75 kDa MIP protein from a crude fraction of spinach leaf intracellular membranes. Upon urea/SDS-PAGE, the 75 kDa protein appeared as a 21 kDa polypeptide, and the 75 kDa species therefore probably represents a tetramer. The corresponding cDNA was obtained by PCR cloning and had an open reading frame encoding a 25.1 kDa protein. The protein, So-deltaTIP, was most homologous to the tonoplast intrinsic protein (TIP) subfamily of plant MIPs. Using affinity-purified So-deltaTIP-specific peptide antibodies, we investigated the subcellular and tissue distribution of So-deltaTIP. So-deltaTIP was specifically located in the vacuolar membrane. It was abundant in most vacuolated cells in all vegetative organs, but was excluded from the leaf epidermis as well as from the root phloem parenchyma and meristem. In spite of the high sequence homology between delta-TIPs of spinach, Arabidopsis, sunflower and radish, their expression patterns were totally different. However, a comparison of the expression pattern of So-deltaTIP with that of more distantly related TIPs showed similarities with Arabidopsis gamma-TIP, which is expressed in zones of cell elongation/differentiation but excluded from meristematic tissues. Meristematic cells are characterized by many small vacuoles as opposed to elongating and mature cells, which generally harbour a single, large vacuole. Our results indicate that the expression of So-deltaTIP may be induced when the large vacuole is formed.

Monoclonal antibody 2G13, a new axonal growth cone marker.

Growth cones are specialized sensorimotor structures at the tips of neurites implicated in pathfinding decisions and axonal outgrowth during neuronal development. We generated a mouse monoclonal antibody (mAb 2G13) against chick tectum and found that the antibody exclusively labelled axonal growth cones, particularly their filopodia and lamellipodia, in developing rat CNS and in embryonic neurons in culture. The high fidelity of the staining of growth cones by mAb 2G13 means that the antibody will be a useful marker for identifying growth cones. In growth cones of cultured neurons, mAb 2G13 labelling is intracellular and mainly associated with the filamentous actin cytoskeleton. Experiments with cytochalasins, which depolymerise filamentous actin, showed that 2G13p (the protein recognised by mAb 2G13) is physically associated with filamentous actin in growth cones. These properties of 2G13p suggest a role in growth cone motility.

Antral follicles develop in xenografted cryopreserved African elephant (Loxodonta africana) ovarian tissue.

The preservation of germ plasm from endangered species could augment captive breeding programs aimed at maintaining genetic diversity. Mammalian female germ plasm (oocytes) is extremely difficult to collect and cryopreserve; however, a promising alternative is the cryopreservation of ovarian tissue. In the present study, athymic nude (nu/nu) Balb/C mice were used to evaluate in vivo viability of cryopreserved ovarian tissue from Institute of Cancer Research genotype (ICR) mice or elephants. Female mice were ovariectomized prior to transplant of cryopreserved-thawed ovarian tissue from ICR mice (n=4) or elephants (n=6). Control mice were sham operated (n=4) or ovariectomized (n=5). Transplants were in the ovarian bursa, enabling in vivo ovulation and pregnancies from allografts. Vaginal cytology was monitored daily, and the intervals between and duration of epithelial cells present in smears were evaluated. Appearance of epithelial cells in sham-operated and allografted mice were at intervals of 4.3+/-0.6 and 3.3+/-0.5 days, lasting for 1.4+/-0.1 and 1.6+/-0.2 days, respectively. Sporadic incidence of epithelial cells in ovariectomized animals occurred at longer intervals (8.6+/-3.8 days). Females with xenografted elephant ovarian tissue demonstrated epithelial cells in vaginal smears at intervals of 4.5+/-1.0 days, for 2.5+/-0.5 days duration, which was significantly longer than the other groups (P < 0.05). Histological evaluation of tissues at the time of epithelial cells in smears demonstrated well-developed antral follicles, although oocytes were of poor morphological appearance or only cumulus-like complexes were seen. The nude mouse model is effective for assessing cryopreserved ovarian tissue xenograft function which can support the development of antral follicles.

Abdominal lipomatosis attributed to tall fescue toxicosis in deer.

Five adult female Eld's deer died acutely or were euthanatized because of clinical signs including anorexia, signs of depression, and uremia. On necropsy, these deer had large masses of necrotic abdominal fat constricting the ureters, causing hydroureter and hydronephrosis. The herd from which these deer originated was maintained on pastures consisting primarily of tall fescue, samples from which were subsequently confirmed to be infected with an endophytic fungus that is known to cause similar lesions in cattle. A retrospective study of deaths in this herd revealed a sharp increase in incidence of abdominal lipomatosis since 1994. Physical examinations on the herd revealed > 90% of females to be affected. Endophyte-infected tall fescue forage was concluded to be a major factor in the development of lipomatosis in these deer. Other contributing factors were considered. Lesions caused by endophyte-infected fescue can be severe, and this disease can develop in nondomestic species.

Evidence of juxtacrine signaling for transforming growth factor alpha in human endometrium.

To determine the mechanism of signaling for transforming growth factor alpha (TGFalpha) in human endometrium, uterine luminal fluid proteins were retrieved by lavage followed by collection of the adjacent endometrium at hysterectomy. In the endometrium we observed the presence of the full-length transmembrane TGFalpha protein and the phosphorylation of its only known receptor, the epidermal growth factor receptor (EGFR), by immunoprecipitation-Western blot; TGFalpha mRNA via reverse transcription-polymerase chain reaction; and immunolocalization of TGFalpha to the surface endometrium adjacent to the uterine lumen. Despite this demonstration of TGFalpha in functional endometrium, we could not detect measurable amounts of TGFalpha in any of the 16 endometrial washings by either immunoprecipitation-Western blot or by ELISA. Recovery rate for intraluminal fluid spiked with TGFalpha control peptide was 93.4-97%. The inability to detect TGFalpha in intraluminal fluid despite its high concentration in cells directly adjacent to the uterine lumen, along with the absence of any cleaved TGFalpha species identified in the endometrium, suggests that TGFalpha signals its receptor as a transmembrane ligand. Since the EGFR is present in the endometrium and on the surface of embryos, these data are consistent with a juxtacrine mode of signaling for TGFalpha between endometrial cells, and between the luminal surface epithelium and preimplantation embryos.

Application of a hybrid computational fluid dynamics and physiologically based inhalation model for interspecies dosimetry extrapolation of acidic vapors in the upper airways.

This study provides a scientific basis for interspecies extrapolation of nasal olfactory irritants from rodents to humans. By using a series of short-term in vivo studies, in vitro studies with nasal explants, and computer modeling, regional nasal tissue dose estimates were made and comparisons of tissue doses between species were conducted. To make these comparisons, this study assumes that human and rodent olfactory epithelium have similar susceptibility to the cytotoxic effects of organic acids based on similar histological structure and common mode of action considerations. Interspecies differences in susceptibility to the toxic effects of acidic vapors are therefore assumed to be driven primarily by differences in nasal tissue concentrations that result from regional differences in nasal air flow patterns relative to the species-specific distribution of olfactory epithelium in the nasal cavity. The acute, subchronic, and in vitro studies have demonstrated that the nasal olfactory epithelium is the most sensitive tissue to the effects of inhalation exposure to organic acids and that the sustentacular cells are the most sensitive cell type of this epithelium. A hybrid computational fluid dynamics (CFD) and physiologically based pharmacokinetic (PBPK) dosimetry model was constructed to estimate the regional tissue dose of organic acids in the rodent and human nasal cavity. The CFD-PBPK model simulations indicate that the olfactory epithelium of the human nasal cavity is exposed to two- to threefold lower tissue concentrations of a representative inhaled organic acid vapor, acrylic acid, than the olfactory epithelium of the rodent nasal cavity when the exposure conditions are the same. The magnitude of this difference varies somewhat with the specific exposure scenario that is simulated. The increased olfactory tissue dose in rats relative to humans may be attributed to the large rodent olfactory surface area (greater than 50% of the nasal cavity) and its highly susceptible location (particularly, a projection of olfactory epithelium extending anteriorly in the dorsal meatus region). In contrast, human olfactory epithelium occupies a much smaller surface area (less than 5% of the nasal cavity), and it is in a much less accessible dorsal posterior location. In addition, CFD simulations indicate that human olfactory epithelium is poorly ventilated relative to rodent olfactory epithelium. These studies suggest that the human olfactory epithelium is protected from irritating acidic vapors significantly better than rat olfactory epithelium due to substantive differences in nasal anatomy and nasal air flow. Furthermore, the general structure of the hybrid CFD-PBPK model used for this study appears to be useful for target tissue dosimetry and interspecies dose comparisons for a wide range of inhaled vapors.

A CFD-PBPK hybrid model for simulating gas and vapor uptake in the rat nose.

In laboratory studies of rodents, the inhalation of organic vapors often results in preferential damage to olfactory epithelium. Such focal lesion formation may be due either wholly or in part to a corresponding nonuniformity in the spatial distribution of vapor uptake within the nasal cavities. As a tool for determining this dose distribution, a mathematical model based on a combination of computational fluid dynamics (CFD) and physiologically based pharmacokinetic (PBPK) modeling was developed for simulating toxicant vapor uptake in the rat nose. The nasal airways were subdivided into four distinct meatuses selected such that each contained a major air flow stream. Each meatus was further divided into four serial regions attached to separate tissue stacks containing mucus, epithelial, and subepithelial compartments. Values for the gas-phase mass transfer coefficients and gas flows in the 16 airway regions were determined by a solution of the Navier-Stokes and convection-diffusion equations using commercially available CFD software. These values were then input to a PBPK simulation of toxicant transport through the 16 tissue stacks. The model was validated by using overall uptake data from rodent inhalation studies for three "unreactive" vapors that were either completely inert (i.e., acetone), reversibly ionized in aqueous media (i.e., acrylic acid), or prevented from being metabolized by an enzyme inhibitor (i.e., isoamyl alcohol). A sensitivity analysis revealed that accurate values of the mass transfer coefficient were not necessary to simulate regional concentrations and uptake of unreactive vapors in the rat nose, but reliable estimates of diffusion coefficients in tissue were crucial for accurate simulations.

Prevalence of endometriosis in adolescent girls with chronic pelvic pain not responding to conventional therapy.

STUDY OBJECTIVE: To evaluate adolescent girls with chronic pelvic pain not responding to conventional medical therapy, using advances in operative laparoscopy to determine endometriosis prevalence, clinical stage, and type of lesion. DESIGN: A descriptive retrospective study of subjects who (1) were referred for the evaluation of chronic pelvic pain, (2) did not respond to a nonsteroidal anti-inflammatory drug and an oral contraceptive pill, and (3) underwent a laparoscopy to determine the etiology of the pelvic pain. SETTING: Patients referred to a surgical gynecologist in a pediatric/adolescent gynecology and reproductive endocrine academic practice. PARTICIPANTS: All patients younger than 22 years of age with chronic pelvic pain. INTERVENTION: Operative laparoscopy to determine the etiology of the chronic pelvic pain. MAIN OUTCOME MEASURES: Operative laparoscopy results including stage and description of endometriosis. RESULTS: More than two thirds of the study population (69.6%) was found to have endometriosis. All subjects had either stage I or II as determined by the American Fertility Society's classification system. The nature of the pain in the 32 subjects with endometriosis was both acyclic and cyclic in 20 (62.5%), acyclic only in 9 (28.1%), and cyclic only in 3 (9.4%). Other presenting symptoms included gastrointestinal in 11 (34.3%), urinary in 4 (12.5%), and irregular menses in 3 (9.4%). CONCLUSIONS: Adolescents with chronic pelvic pain not responding to medical therapy have a high rate of endometriosis and should be referred to a gynecologist who is experienced with the subtle laparoscopic findings of atypical endometriosis to diagnose the etiology of the pelvic pain and initiate appropriate therapy.