Directional analysis of cardiac motion field from gated fluorodeoxyglucose PET images using the Discrete Helmholtz Hodge Decomposition.

OBJECTIVES: Extract directional information related to left ventricular (LV) rotation and torsion from a 4D PET motion field using the Discrete Helmholtz Hodge Decomposition (DHHD). MATERIALS AND METHODS: Synthetic motion fields were created using superposition of rotational and radial field components and cardiac fields produced using optical flow from a control and patient image. These were decomposed into curl-free (CF) and divergence-free (DF) components using the DHHD. RESULTS: Synthetic radial components were present in the CF field and synthetic rotational components in the DF field, with each retaining its center position, direction of motion and diameter after decomposition. Direction of rotation at apex and base for the control field were in opposite directions during systole, reversing during diastole. The patient DF field had little overall rotation with several small rotators. CONCLUSIONS: The decomposition of the LV motion field into directional components could assist quantification of LV torsion, but further processing stages seem necessary.

Biomagnetic characterization of spatiotemporal parameters of the gastric slow wave.

Certain gastric disorders affect spatiotemporal parameters of the gastric slow wave. Whereas the electrogastrogram (EGG) evaluates electric potentials to determine primarily temporal parameters, fundamental physical limitations imposed by the volume conduction properties of the abdomen suggest the evaluation of gastric magnetic fields. We used a multichannel superconducting quantum interference device magnetometer to study the magnetogastrogram (MGG) in 20 normal human subjects before and after a test meal. We computed the frequency and amplitude parameters of the gastric slow wave from MGG. We identified normal gastric slow wave activity with a frequency of 2.6 +/- 0.5 cycles per minute (cpm) preprandial and 2.8 +/- 0.3 cpm postprandial. In addition to frequency and amplitude, the use of surface current density mapping applied to the multichannel MGG allowed us to visualize the propagating slow wave and compute its propagation velocity (6.6 +/- 1.0 mm s(-1) preprandial and 7.4 +/- 0.4 mm s(-1) postprandial). Whereas MGG and EGG signals exhibited strong correlation, there was very little correlation between the MGG and manometry. The MGG not only records frequency dynamics of the gastric slow wave, but also characterizes gastric propagation. The MGG primarily reflects the underlying gastric electrical activity, but not its mechanical activity.

Influence of formulation on bioavailability of theophylline.

The bioavailability of theophylline from formulations containing this drug alone and also in combination with phenobarbital and ephedrine has been studied in normal volunteers and asthmatic subjects. Neither of the latter two drugs had any significant influence on the bioavailability of theophylline. A complexation phenomenon, previously reported to inhibit dissolution of theophylline and phenobarbital in vitro, does not affect the bioavailability of theophylline from solid formulations. No differences were observed in the pharmacokinetics of theophylline between normal and asthmatic subjects.

Increase in androgen:estrogen ratio specifically during low-dose follicle-stimulating hormone therapy for polycystic ovary syndrome.

OBJECTIVES: To compare changes in serum androgens in women with polycystic ovary syndrome (PCOS) during ovulation induction with low-dose versus conventional urofollitropin. DESIGN: Prospective case-control study. SETTING: Tertiary-care reproductive medicine center. SUBJECTS: Thirty-three women with PCOS who failed to conceive with clomiphene citrate therapy. INTERVENTIONS: Urofollitropin (low-dose, 75 IU; conventional dose, 150 IU) was administered IM daily. Therapy was monitored by serum E2 and vaginal sonography. Hormone determinations were performed by immunoassay. MAIN OUTCOME MEASURES: Serum E2, androstenedione (A), T, and LH levels. RESULTS: On the day of hCG administration, patients treated with low-dose therapy exhibited significantly higher ratios of A to E2 (3.5 +/- 0.5 versus 2.2 +/- 0.3 [mean +/- SEM]) and T to E2 (1.5 +/- 0.3 versus 1.0 +/- 0.1) compared with conventional urofollitropin therapy. The number of follicles > or = 16 mm in diameter was significantly lower with low-dose therapy (2.7 +/- 0.6 versus 5.4 +/- 0.4). CONCLUSIONS: Although low-dose therapy was associated with a reduction in the number of recruited follicles, the increase in androgen to E2 associated with this therapy may adversely affect oocyte quality and may explain the relatively high miscarriage rate reported in PCOS patients with this therapy.

Reduced pregnancy outcome in patients with unilateral or bilateral hydrosalpinx after in vitro fertilization.

In a retrospective study, we compared 118 patients with hydrosalpinx and 157 patients with bilateral salpingectomy entering an established in vitro fertilisation programme between 1988 and 1992. Patients with unilateral or bilateral hydrosalpinx had a lower clinical pregnancy rate, a higher miscarriage rate, and a lower ongoing pregnancy rate than patients with absent Fallopian tubes.

The role of the iliolumbar ligament in low back pain.

Low back pain is caused by a variety of etiologies. Some clinicians have postulated that much low back pain is due to trauma to the iliolumbar ligament. The iliolumbar ligament is one of the three pelvic-lumbar ligaments and develops during the 12th week of gestation. The iliolumbar ligament appears to be a major stabilizing component between the vertebral spine and the pelvis. The innervation of the iliolumbar ligament appears similar to the posterior lumbar ligaments. Our hypothesis is: micro-trauma to the iliolumbar ligament is the primary cause of many cases of chronic low back pain because (1) it is the weakest component of the multifidus triangle; (2) there is increased susceptibility to injury due to its angulated attachment; (3) it is a primary inhibitor of excess sacral flexion; (4) it is a highly innervated nociceptive tissue; and (5) it plays an increased role with progressive disc degeneration.

Use of a gonadotropin releasing hormone agonist before vaginal surgery for cervical leiomyomas. A report of two cases.

Two cases of cervical myoma were treated with combined medical/surgical therapy using a gonadotropin releasing hormone agonist (GnRH-a) and transvaginal cervical myomectomy. Patients were treated with depot GnRH-a (leuprolide acetate) for two months followed by myomectomy. This approach allowed successful treatment with short hospitalization (< 24 hours). Potential benefits of this regimen include decreased intraoperative blood loss, outpatient management, decreased morbidity, decreased hospital expense and preservation of reproductive potential by avoiding hysterectomy.

Biomagnetic signatures of uncoupled gastric musculature.

Gastric slow waves propagate in the electrical syncytium of the healthy stomach, being generated at a rate of approximately three times per minute in a pacemaker region along the greater curvature of the antrum and propagating distally towards the pylorus. Disease states are known to alter the normal gastric slow wave. Recent studies have suggested the use of biomagnetic techniques for assessing parameters of the gastric slow wave that have potential diagnostic significance. We present a study in which the gastric syncytium was uncoupled by mechanical division as we recorded serosal electric potentials along with multichannel biomagnetic signals and cutaneous potentials. By computing the surface current density (SCD) from multichannel biomagnetic recordings, we were able to quantify gastric slow wave propagation as well as the frequency and amplitude of the slow wave and to show that these correlate well with similar parameters from serosal electrodes. We found the dominant slow wave frequency to be an unreliable indicator of gastric uncoupling as uncoupling results in the appearance of multiple slow wave sources at various frequencies in external recordings. The percentage of power distributed in specific frequency ranges exhibited significant postdivision changes. Propagation velocity determined from SCD maps was a weak indicator of uncoupling in this work; we believe that the relatively low spatial resolution of our 19-channel biomagnetometer confounds the characterization of spatial variations in slow wave propagation velocities. Nonetheless, the biomagnetic technique represents a non-invasive method for accurate determination of clinically significant parameters of the gastric slow wave.

Early follicular rise of serum progesterone concentration in response to a flare-up effect of gonadotrophin-releasing hormone agonist impairs follicular recruitment for in-vitro fertilization.

A retrospective study of 150 cycles of in-vitro fertilization (IVF) was undertaken to determine the impact of elevated serum progesterone in the early follicular phase of IVF cycles utilizing gonadotrophin-releasing hormone agonist (GnRHa) initiated in the follicular phase. A total of 127 patients identified as being at risk for poor response to stimulation were treated with a flare-up protocol of GnRHa combined with high dose follicle stimulating hormone (FSH). Patients were excluded for severe male factor requiring micromanipulation. Patients were stimulated with GnRHa beginning on cycle day 2, and high dose FSH beginning on cycle day 3. Some 85% of the cycles exhibited a rise of serum progesterone to a peak concentration of > 1.0 ng/ml (range, 1.2-4.2 ng/ml) during cycle days 2-6. When compared to cycles with no demonstrable progesterone rise, cycles with a rise were associated with a significantly decreased ovarian response: more ampoules of gonadotrophin were required (mean 26.8 versus 22.6, P < 0.05), lower peak oestradiol concentration was reached (mean 774 pg/ml versus 1030; P < 0.05), and fewer mature oocytes were harvested (mean 4.6 versus 7.5; P < 0.01). Among the different pregnancy outcomes (clinical pregnancy, no pregnancy, ongoing pregnancy, and miscarriage), there were no significant differences detected in the early follicular progesterone concentrations as measured by peak progesterone, progesterone area under the curve (days 2-6), and day of peak progesterone. The follicular phase initiation of GnRHa can result in significant elevations of serum progesterone in the early follicular phase, which may impair follicular recruitment and overall ovarian response.