Basins of attraction of a nonlinear nanomechanical resonator

We present an experiment that systematically probes the basins of attraction of two fixed points of a nonlinear nanomechanical resonator and maps them out with high resolution. We observe a separatrix which progressively alters shape for varying drive strength and changes the relative areas of the two basins of attraction. The observed separatrix is blurred due to ambient fluctuations, including residual noise in the drive system, which cause uncertainty in the preparation of an initial state close to the separatrix. We find a good agreement between the experimentally mapped and theoretically calculated basins of attraction.

A comparison of anti-desmoglein antibodies and indirect immunofluorescence in the serodiagnosis of pemphigus vulgaris

BACKGROUND

Indirect immunofluorescence (IIF) is the standard method for the detection of pemphigus autoantibodies. Commercially available enzyme-linked immunosorbent assays (ELISAs) have recently become available to measure serum antibodies (Abs) against desmoglein1 (Dsg1) and desmoglein3 (Dsg3). It has been suggested that patients with mucosal-dominant pemphigus vulgaris (PV) have serum Abs against Dsg3 only, patients with mucocutaneous PV have Abs to both Dsg1 and Dsg3, and patients with pemphigus foliaceus (PF) have Abs against Dsg1 only.

AIM

To compare the sensitivity and specificity of the IIF and ELISA tests in the diagnosis of pemphigus and its subsets.

METHODS

Thirty-three patients with PV and five patients with PF were studied, and compared with 50 healthy individuals or patients with unrelated skin diseases. Monkey esophagus was used as a substrate for the IIF test.

RESULTS

The IIF and ELISA tests were each positive in 26 of the 32 (81%) PV patients, and in none (0%) and 3 (6%) of the 50 controls, respectively. Both the IIF and ELISA results were concordant in 69% of the PV patients, and only one of these two tests was positive in the remaining 31% of patients. Forty-six per cent of the PV patients with a positive ELISA test did not have the PV phenotype (mucosal or mucocutaneous) predicted by their autoantibody profile.

CONCLUSION

The IIF and ELISA tests may be used as complementary tests for the serologic diagnosis of pemphigus.

Preliminary crystallographic study of turkey gizzard vinculin

Vinculin is a 117 kDa microfilament-associated protein located at the cytoplasmic aspects of focal contacts and cell-cell adherens type junctions. In both sites, vinculin participates in the formation of a submembrane 'plaque' structure which is responsible for the attachment of actin filaments to the plasma membrane. Vinculin consists of 1066 amino acids, which form a large 90 kDa globular head domain and a rod-like 29 kDa tail domain. The two domains are separated by several stretches of proline residues where the major proteolytic cleavage sites are located. The experimental procedure for isolation and purification of vinculin from smooth muscle has been developed and crystals of native vinculin suitable for X-ray analysis have been obtained. The homogeneity of the vinculin solution was analyzed prior to crystallization using dynamic light scattering. Crystals of vinculin have been obtained in buffer containing 2 mg ml(-1) protein, 0.9 M ammonium sulfate, 0.1 M MES pH 6.5 using both the hanging-drop and sitting-drop vapour-diffusion methods. The crystals have the form of rhombic plates and grow to maximal dimensions of 0.3 x 0.3 x 0.05 mm in two weeks. Preliminary X-ray data show that the crystals diffract to 3.5 A resolution at the X11 beamline of DESY and belong to the monoclinic space group P2(1). Crystal unit-cell parameters are estimated to be a = 57, b = 351, c = 70 A, alpha = 90, beta = 113, gamma = 90 degrees.

Immediate versus delayed treatment of perimenopausal bleeding due to benign causes by balloon thermal ablation

STUDY OBJECTIVE

To compare the effectiveness and safety of thermal balloon ablation without pretreatment with endometrium-thinning agents compared with delayed ablation with pretreatment for women with perimenopausal menorrhagia.

DESIGN

Prospective, randomized, controlled trial (Canadian Task Force classification I).

SETTING

Hospital-based ambulatory medical center.

PATIENTS

Thirty women age 46 to 51 years with severe enough perimenopausal menorrhagia to make them candidates for either hysterectomy or endometrial ablation. Two patients with submucosal myomas and six who had undergone cesarean section were included.

INTERVENTIONS

Thirteen patients were randomly assigned to be treated within 30 days and received a single intramuscular administration of gonadotropin releasing hormone (GnRH) analog; 17 women were allocated to be treated within 3 days of enrollment without uterine preparation. A thermal balloon was inserted transcervically under general anesthesia, and after inflation in the endometrial cavity with 5% dextrose in water, was heated to 87 degrees C for 8 minutes.

MEASUREMENTS AND MAIN RESULTS

Immediate and long-term major and minor complications and success rates were analyzed. Bleeding patterns and mean duration of menstrual flow were compared between groups at 6-month follow-up. No major intraoperative or postoperative complications occurred in either group, including the women who had recently undergone hysteroscopic myomectomy or had a history of cesarean section. Minor side effects were similar in both groups, and did not exceed 5%. Overall, at 6-month follow-up, 7 women were amenorrheic, 20 hypomenorrheic, and 3 eumenorrheic. No significant differences were noted between women treated with immediate or delayed ablation in either the distribution of bleeding patterns or days of flow per cycle (mean +/- SEM 1.8 +/- 0.42 vs 2.1 +/- 0.75 days, respectively).

CONCLUSION

This pilot study suggests that prompt treatment of perimenopausal menorrhagia with thermal balloon endometrial ablation is as effective and safe as deferred therapy combined with GnRH analog as an endometrium-thinning agent. In light of our results, the theory that previous cesarean section and presence of small submucosal myomas constitute relative contraindications for the procedure merits further consideration. (J Am Assoc Gynecol Laparosc 6(2):145-150, 1999)

Vaginal ultrasonography in patients with postmenopausal bleeding

Our objective was to define a subset of women with postmenopausal bleeding in whom the accepted practice of endometrial sampling could be safely omitted. Vaginal endosonographic measurements were compared to the histological findings of curettings following diagnostic dilatation and curettage in 129 women with post-menopausal bleeding who were not receiving hormonal therapy. Atrophy was diagnosed in 49%, slight proliferation in 10%, endometrial polyps in 11%, hypoplasia in 12%, and adenocarcinoma in 12%. Endometrial atrophy was associated with a mean sonographic thickness of 2.6 mm of the double layer (range 0-6.5 mm). Of the women with a final histological diagnosis of atrophy, 92% had an endometrial thickness of 3 mm or less. Furthermore, all women with a sonographic endometrial thickness of 3 mm or less had atrophic endometrium (p < 0.0001). An endometrial thickness of 3 mm or less would have reduced the number of dilation and curettage procedures by 45% and no cases of endometrial pathologies would have been missed. In women presenting with postmenstrual bleeding, meticulous scanning of the endometrium can select a group where endometrial sampling can be omitted from the protocol.

Gradual cervical dilation for termination of early second-trimester pregnancy with a double balloon device

Thirty-two women with pregnancies of 12-15 weeks underwent cervical dilation before abortion using a double balloon device. In all cases, satisfactory dilation was achieved and evacuation accomplished. The slow dilation process, resulting from the continuous indirect dilator effect of the balloons, was not associated with patient inconvenience in most cases. Larger dilation was achieved by adding a continuous instillation of extraovular prostaglandin E2 solution through the device. The double balloon device is a convenient and safe cervical dilator and may be a suitable method for cervical dilation before abortion.