Further comments on the induction of lung tumors by plutonium dioxide in beagles.

A series of recent papers describes the final results obtained from studies of the effects of inhaled plutonium dioxide on beagle dogs. This note considers the value of a microdosimetric assessment of these data. In particular, it offers support for the existence of a threshold for the induction of lung tumors.

A microdosimetric reassessment of new data on the effects of plutonium dioxide inhalation by beagle dogs.

Traditionally, the assessment of the effects of radiation on living tissue has been made in terms of absorbed dose. This concept, however, might not be the most appropriate when considering the effects arising from the inhalation of insoluble radioactive particulates in inhomogeneous tissue such as the lung. We have therefore applied microdosimetric methods to this problem and, in particular, investigated in detail how energy depositions are distributed when alpha particles travel through parenchymal lung tissue. Sections of material derived from rat, beagle and human lung were examined in an image analyzer, and an imaginary plutonium dioxide particulate was placed on the surface of an alveolar sac. The hypothetical alpha particles emitted from it were followed to the ends of their tracks so that the effects of the material's real structure could be followed in detail. It was found that, taking such detail into account, the alpha particles traveled much greater distances than might have been thought on the basis of a uniform, structureless lung. It was also found that the specific energy distributions can cover several orders of magnitude and can differ significantly between tissue as a whole, cells and nuclei at low exposures. Attempts are made to correlate these results with recently published data on beagle dogs that had inhaled graded exposure levels of plutonium dioxide aerosols.

Conservative management of delayed suprapubic abscess after laparoscopic Burch colposuspension using nonabsorbable polypropylene mesh.

To our knowledge, abscess formation after laparoscopic Burch colposuspension using permanent surgical mesh has not been previously reported. In our patient a suprapubic abscess was identified 4 weeks after the procedure in which polypropylene mesh was used. Conservative management involving drainage under computerized tomographic guidance and antibiotic therapy resulted in complete resolution without necessitating removal of the mesh. (J Am Assoc Gynecol Laparosc 6(2):225-228, 1999)

Effect of selected monoterpenes on methane oxidation, denitrification, and aerobic metabolism by bacteria in pure culture.

Selected monoterpenes inhibited methane oxidation by methanotrophs (Methylosinus trichosporium OB3b, Methylobacter luteus), denitrification by environmental isolates, and aerobic metabolism by several heterotrophic pure cultures. Inhibition occurred to various extents and was transient. Complete inhibition of methane oxidation by Methylosinus trichosporium OB3b with 1.1 mM (-)-alpha-pinene lasted for more than 2 days with a culture of optical density of 0.05 before activity resumed. Inhibition was greater under conditions under which particulate methane monooxygenase was expressed. No apparent consumption or conversion of monoterpenes by methanotrophs was detected by gas chromatography, and the reason that transient inhibition occurs is not clear. Aerobic metabolism by several heterotrophs was much less sensitive than methanotrophy was; Escherichia coli (optical density, 0.01), for example, was not affected by up to 7.3 mM (-)-alpha-pinene. The degree of inhibition was monoterpene and species dependent. Denitrification by isolates from a polluted sediment was not inhibited by 3.7 mM (-)-alpha-pinene, gamma-terpinene, or beta-myrcene, whereas 50 to 100% inhibition was observed for isolates from a temperate swamp soil. The inhibitory effect of monoterpenes on methane oxidation was greatest with unsaturated, cyclic hydrocarbon forms [e.g., (-)-alpha-pinene, (S)-(-)-limonene, (R)-(+)-limonene, and gamma-terpinene]. Lower levels of inhibition occurred with oxide and alcohol derivatives [(R)-(+)-limonene oxide, alpha-pinene oxide, linalool, alpha-terpineol] and a noncyclic hydrocarbon (beta-myrcene). Isomers of pinene inhibited activity to different extents. Given their natural sources, monoterpenes may be significant factors affecting bacterial activities in nature.

Comparison of the harmonic scissors and endostapler in laparoscopic supracervical hysterectomy.

We conducted a retrospective analysis of 29 consecutive patients undergoing laparoscopic supracervical hysterectomy to compare outcomes using the endostapler (15 women) versus harmonic scissors (14). Both instruments resulted in similar outcomes with regard to operating room time, blood loss, and hospital stay. The harmonic scissors have the advantage of decreasing patient cost compared with the stapler.

Laparoscopic supracervical hysterectomy versus laparoscopic-assisted vaginal hysterectomy.

This retrospective study compared 41 patients, 21 undergoing laparoscopic-assisted hysterectomy (LAVH) and 20 undergoing laparoscopic supracervical hysterectomy (LSH). The groups were comparable in age, weight, and previous abdominal surgeries. Surgical indications were similar with the exception of uterine carcinoma, which was always treated by LAVH. Vaginal repairs were more common in the LAVH group. The mean operative times, estimated blood losses, uterine weights, and hospital stays were all comparable for both groups. A potential advantage of LSH is that it requires less operative dissection of the bladder, ureter, bowel, and uterine artery. The possible disadvantage of LSH is the 10% frequency of cyclic stump bleeding. Larger studies with prolonged follow-up will be necessary to evaluate risks and benefits of the procedures.

Signal preprocessing system for the small intestinal electromyogram.

The intestinal EMG obtained from chronically implanted electrodes in canine preparations provides for the evaluation of intestinal motor activity and its control. The basic electrical rhythm (BER) and spike components on the EMG signal provide evidence of control activity and a measure of contraction intensity, respectively. A hardware system is presented in which these two components are separated by filters and the contraction spikes counted in fixed epochs to yield a contraction spike per unit time record against time. The signal is also available in parallel binary form at the end of each epoch, together with a data-ready signal for direct acquisition by computer. Tests of system performance and operating protocols are given. The preprocessor is used as a fast front end to a digital signal processing system specifically built for intestinal EMG analyses.

The volumes of rat and human lung cells as measured by an image analyser.

Previous studies of the morphometry of lung cells have required long and tedious measurements involving serial sectioning and the reconstruction of models. However the advent of computer-based image analysers offers a more straightforward, although less direct, method of making such measurements. In the present study a Magiscan has been used to investigate the shapes and sizes of the nuclei from the lung cells of three mammalian species. Associated cellular volumes have also been derived. Based on the measurements of about two hundred cells the mean volumes of rat, beagle and human lung cell nuclei were estimated to be 67 microns 3, 41 microns 3 and 78 microns 3 respectively. Cell volumes were estimated to be about 500 microns 3. It was also confirmed that a sphere is a very poor approximation for the shape of a nucleus, spheroids representing the observations much more closely.

Intravenous ritodrine as a possibly provocative predictive test in gestational diabetes. A case report.

A 24-year-old, nonobese, gestational diabetic woman developed diabetic ketoacidosis while receiving intravenous ritodrine therapy to suppress premature labor. This case emphasizes the necessity for close observation of any gestational diabetic during intravenous ritodrine tocolysis and suggests the possibility of predicting diabetes in pregnant patients exhibiting marked glucose intolerance during therapy.

Ultrasonic diagnosis of intracranial teratoma in utero. A case report and literature review.

Intracranial teratoma was detected ultrasonically in utero. The infant died before term. Neonatal mortality seems to be inevitable with this condition. It is important to distinguish this entity from hydrocephalus, which is recognized more frequently.

Serum carotene levels in female long-distance runners.

Hypercarotenemia has been associated with anorexia nervosa and hypothalamic amenorrhea. With the emergence of a spectrum of menstrual dysfunction, including anovulation in women runners, the hypothesis of hypothalamic amenorrhea in these patients has been formulated. Other authors have proposed exercise-associated amenorrhea to be distinct from hypothalamic amenorrhea based on endocrine profiles. Using carotene as an index test of hypothalamic amenorrhea, we have studied female long-distance runners (greater than 25 miles/week) and have found no difference in the carotene levels between ovulatory (midfollicular) and anovulatory runners. These data support other evidence that exercise-associated amenorrhea is distinct from hypothalamic amenorrhea.

Intrapartum pulmonary embolus. A case report.

Intrapartum pulmonary embolus is rare. In a case we encountered, both the mother and infant survived. The peripartum period is a relative contraindication to the use of thrombolytic therapy due to the risk of postpartum hemorrhage. The indications for embolectomy and vena caval interruption are the same as the ones generally accepted.

Twenty four-hour prolactin profiles and prolactin responses to dopamine in long distance running women.

Long distance women runners have a high incidence of oligoamenorrhea. In order to study the possible role of PRL in contributing to their menstrual dysfunction, we evaluated PRL secretion in eumenorrheic (n = 7) and oligomenorrheic runners (n = 9) who averaged 25-50 miles/week, as well as nonrunning women (n = 5) during the midfollicular phase of their cycles. Serum estradiol, progesterone, testosterone, FSH, LH, TSH, and T4 were similar among the three groups. The mean 24-h +/- SE PRL concentrations between the three groups: nonrunners, 12.9 +/- 0.6 ng/ml; eumenorrheic runners, 13.5 +/- 0.4 ng/ml; and oligomenorrheic runners, 15.0 +/- 0.8 ng/ml, were not significantly different. A dopamine (DA) infusion, 0.004 micrograms/kg X min, produced physiologic serum DA levels in these subjects. The nadir of serum PRL levels during DA infusion was similar in each group, which argues against an abnormality in dopaminergic tone in the runners with menstrual dysfunction. Our findings of normal 24-h PRL secretion and appropriate PRL responses to DA in women runners with menstrual dysfunction do not support a role for PRL in this disorder.

Calcium levels in normal and hypertensive pregnant patients.

Epidemiologic studies of hypertension in nonpregnant patients have suggested that abnormal calcium metabolism contributes to the genesis of hypertension. We have studied serum ionized calcium, total calcium, phosphorus, magnesium, total protein, and albumin in 16 normal pregnant women, 12 gravid patients with chronic hypertension, and 31 gravid patients with pregnancy-induced hypertension. In contradistinction to the reported difference in ionized calcium between nonpregnant normal and hypertensive patients, we have found no difference in serum ionized calcium between our groups.

Assessment of mammary lactogenic receptor changes in pregnant rabbits.

Lactogenic receptor was purified from rabbit mammary tissue and used to generate an antiserum in goats. The purified lactogenic receptor material bound lactogenic hormones specifically and reversibly. Antiserum generated in a goat bound a labeled human growth hormone/receptor complex; this was displaced by nonlabeled solubilized receptor preparations. This was used as a radioimmunoassay and was able to detect 0.037 fmol of lactogenic receptor. The specificity of the radioimmunoassay for lactogenic receptor was supported by three lines of evidence; first, the ligand used in the radioimmunoassay was an iodine 125-labeled human growth hormone/receptor combination; therefore, only membrane protein with structural homology to the protein which bound 125I-labeled human growth hormone competed for binding to the antiserum; second, depletion of radioreceptor binding sites by affinity chromatography with ovine prolactin as the fixed ligand was detected; third, an increase in breast lactogenic receptor during pregnancy was detected by both radioreceptor assay and the radioimmunoassay. We found a progressive increase in lactogenic receptors by radioimmunoassay which corresponded to parallel increases by radioreceptor assay in rabbit mammary tissue during pregnancy.

Microdosimetry of alpha-irradiated lung.

Measurements have been made on the fractions of tissue affected and distributions of energy deposited when rat and human lung are irradiated by alpha particles. Thin sections of alveolar tissue were examined in an image analyser and an imaginary 239PuO2 particle was placed in an alveolar sac. The hypothetical alpha particles were followed to the ends of their tracks so the effects of the material's real structure could be examined in detail. It is shown that a fair comparison exists with results previously obtained with hamster lung. In addition, the measurements actually made with human lung correlate well with predictions based on the rat lung measurements. Finally, it is confirmed that the approximation of a uniform, structureless lung is a poor one.

Metastatic breast cancer complicating pregnancy. A case report.

An 18-year-old patient at 15 weeks' gestation was hospitalized for a high fever and delirium secondary to a presumed viral syndrome. She had massive hepatomegaly, and a small breast lump was noted incidentally. Abnormalities in the differential blood count and liver function tests were found in addition to thrombocytopenia. Bone marrow biopsy revealed metastatic breast cancer.