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PubMed1990

A comparison of antiarrhythmic drugs for the suppression of ventricular ectopic depolarizations: a meta-analysis.

This article reports the results of a meta-analysis of the effectiveness of antiarrhythmic drugs for the suppression of ventricular ectopic depolarizations. We analyzed 97 published articles that referred to a total of 27 drugs and contained data from 2989 patient-treatment trials; our goal was to determine the number of patients responding to therapy, defined as greater than or equal to 80% suppression of ventricular ectopic depolarizations. By means of logistic regression we tested the effect of 10 clinical and experimental variables on the likelihood of response to therapy. The likelihood of a drug response was significantly affected by the following six variables: increased by the use of dose titration (t = 3.59, p less than 0.0001), increased by the use of a higher daily dose (t = 3.21, p less than 0.0001), decreased by older age (t-2.67, p = 0.004), decreased by the use of blinding (t = -2.28, p = 0.011), increased by treating more male patients (t = 1.72, p = 0.043), and decreased by the presence of cardiovascular disease (t = -1.52, p = 0.064). Incorporating these six variables into our logistic regression model, we adjusted the response rate in each published study and calculated the mean response and standard error for each drug. Of the drugs tested in at least 100 patients, the most effective were amiodarone (estimated response rate 90%), encainide (80%), flecainide (79%), and propafenone (74%). Class IC drugs were significantly more effective than class IB and II drugs (p less than 0.05). With the exception of lorcainide and moricizine, class IC drugs were also more effective than class IA drugs (p less than 0.05). Amiodarone was significantly more effective than all drugs except encainide and flecainide (p less than 0.05). We found no significant differences among the response rates to class IA, IB, and II drugs. Whereas several patient and study characteristics affect the likelihood of response to antiarrhythmic drugs, class IC drugs and amiodarone are significantly more effective than other drugs in suppressing ventricular ectopic depolarizations.

Anti-Arrhythmia Agents↗
PubMed1993

Transvaginal ultrasonographic findings in surgically verified ectopic pregnancy.

OBJECTIVE: Our purpose was to evaluate transvaginal ultrasonographic findings in ectopic pregnancies for positive ultrasonographic sign(s). STUDY DESIGN: Eighty-nine patients admitted with an ectopic pregnancy from September 1987 through September 1989 were retrospectively reviewed. Sixty-nine had undergone transvaginal ultrasonography within 10 days before surgery. The ultrasonographic examinations were reviewed by four radiologists. RESULTS: Ultrasonography revealed adnexal masses in 54 patients (78%). Thirty-six masses had an appearance consistent with an adnexal ring. Twenty-four adnexal rings demonstrated a thin sonolucent area surrounding the ring, a "halo sign" (67%). A control group of 116 intrauterine pregnancies were evaluated by ultrasonography. Forty-one women had adnexal cysts. Twenty-seven of these had an adnexal ring; only two of these had halos. CONCLUSION: The halo sign is presumptive evidence of a living ectopic pregnancy and, when identified, may allow earlier diagnosis and intervention.

Adnexa Uteri↗
PubMed1988

Colony-forming ectopic granule cells in the cerebellar primary fissure of normal adult rats: a morphologic and morphometric study.

The morphology and degree of maturation of intrafissural colony-forming ectopic granule cells (EGCs) were investigated in the cerebella of normal adult rats. These EGCs exhibit a notable degree of morphological maturity, with 2-5 short dendrites radiating from a globular soma, typical dendritic claw-like terminals and descending axons. The EGCs receive the afferent input of mossy fiber terminals and their axons also establish homologous synapses with the postsynaptic dendritic spines of the Purkinje cells. Although these EGCs exhibit the typical morphology of mature granule cells, the morphometric analysis shows, however, a significant reduction in the number of dendrites (mean 3.30 +/- 0.60) and 'claws' (mean 3.66 +/- 0.12) in the EGCs with respect to the controls (mean 3.85 +/- 0.73 and 4.53 +/- 0.13, respectively). These differences may be indicative of a slight numerical mismatching between EGCs and afferent mossy fibers, which limit the input that the ectopic neurons receive. The karyometric study also showed that the average nuclear area in EGCs was significantly smaller (mean 19.38 +/- 0.24 micron2) than in controls (mean 21.88 +/- 0.24 micron2), suggesting a positive correlation between nuclear size and the number of postsynaptic dendritic terminals available in the granule cells. The influence of some morphogenetic factors on the degree of maturity attained by these ectopic neurons is discussed, particularly the interactions of mossy fibers and astrocytes with maturing EGCs.

Animals↗
PubMed1993

Internodal potassium currents can generate ectopic impulses in mammalian myelinated axons.

Positive clinical symptoms can arise from ectopic action potentials in several disorders of myelinated axons. Here we report that an elevated K+ concentration in the periaxonal, internodal space can cause internodal K+ currents to become excitatory, resulting in slow potential oscillations and associated bursts of ectopic spikes. Ectopic firing may therefore be favoured by conditions in which periaxonal K+ buffering is compromised.

Action Potentials↗
PubMed1992

Distinct effects of ectopic expression of Wnt-1, activin B, and bFGF on gap junctional permeability in 32-cell Xenopus embryos.

A polarity in gap junctional permeability normally exists in 32-cell stage Xenopus embryos, in that dorsal cells are relatively more coupled than ventral cells, as measured by transfer of Lucifer yellow dye. The current study extends our analysis of whether gap junctional permeability at this stage can be modulated by secreted factors, and whether the polarity in gap junctional permeability correlates with the effects of ectopic expression of these secreted factors on the subsequent phenotype of the developing embryo. Following ectopic expression of activin B or Wnt-1, but not bFGF, the transfer of Lucifer yellow between ventral animal pole cells is detected in a greater percentage of 32-cell stage embryos. This increased incidence of dye transfer between ventral cells correlates with axial duplications later in development. However, there are differences in the extent of Lucifer yellow transfer between animal and vegetal hemisphere blastomeres which is dependent on whether activin B or Wnt-1 RNA had previously been injected. These results suggest that enhanced gap junctional permeability between ventral cells of 32-cell Xenopus embryos correlates with subsequent defects in the dorsoventral axis, although there are at present no direct data demonstrating a role for gap junctions in establishment or maintenance of this axis. Moreover, while both activin B and bFGF are mesoderm-inducing growth factors, only activin B has effects on gap junctional permeability in 32-cell embryos following ectopic expression, demonstrating an interesting difference in physiological responses to expression of these factors.

Activins↗
PubMed1988

Growth hormone is secreted by ectopic pituitary grafts and stimulates maternal behavior in rats.

The onset of maternal behavior at parturition in rats is hormonally regulated. Recently, we reported that treatment of behaviorally inexperienced, hypophysectomized (hypox), ovariectomized (ovx) rats with a sequential steroid treatment of progesterone (P) and estradiol (E2), and either ectopic anterior pituitary grafts or prolactin (PRL), stimulated maternal responsiveness toward foster young. That growth hormone (GH) has a number of PRL-like activities led us to ask whether the actions of PRL on maternal behavior were specific to PRL or might be shared by other PRL-like protein hormone, i.e., GH. In Experiment 1 we quantified plasma concentrations of GH and PRL by RIA in groups of hypox female rats that were ovariectomized and treated with a combination of ectopic pituitary grafts (Days 1-23) and Silastic capsules filled with P (Days 1-11) and E2 (Days 11-23). Blood samples were collected from Days 1 to 23 of treatment. Both plasma PRL and GH levels increased after grafting, initially rising 10- to 60-fold by Day 4 and gradually declining throughout the remainder of the 23-day sampling period. Throughout the 3-week period after grafting plasma GH levels were as high or higher than those of PRL. In Experiment 2 the behavioral effects of exogenously administered ovine (o)-GH were measured in groups of hypox, ovx rats that were treated with P and E2 as in Experiment 1. Experimental rats were injected twice daily with 0.25 mg oGH beginning on Day 1. Testing for maternal behavior toward foster young was conducted daily from Day 12 to Day 22. In steroid-treated rats, GH treatment stimulated a more rapid onset of maternal behavior (latencies of 3 vs greater than 10 days for vehicle-injected controls). These data indicate that GH, like PRL, is secreted by ectopic pituitary grafts and is capable of stimulating maternal behavior.

Animals↗
PubMed1986

Aortic body tumour with adjacent ectopic thyroid tissue in a dog.

A 12-year-old neutered male Husky dog had a neoplasm at the base of the heart which did not invade surrounding tissues. Microscopically, the neoplasm was composed of nests and sheets of polyhedral cells subdivided into lobules by trabeculae of fine fibrovascular stroma. Adjacent to the neoplasm was a rim of ectopic thyroid tissue that appeared histologically normal. The possible differential diagnoses for the neoplasm were aortic body tumour, ectopic thyroid tumour and ectopic parathyroid tumour; the ultrastructural characteristics revealed it to be an aortic body tumour.

Animals↗
PubMed1987

Catecholaminergic control of plasma growth hormone and thyrotropin levels in hypophysectomized rats bearing ectopic pituitary transplants.

Transplantation of the anterior pituitary to an ectopic site leads to stimulation of PRL secretion and suppression of the release of other adenohypophyseal hormones. We have previously reported that precursors and blockers of catecholamine synthesis can affect PRL release from the ectopic pituitary. In the present study we have measured the effects of L-3,4-dihydroxyphenylalanine (DOPA), DL-threo-dihydroxyphenylserine (DOPS), alpha-methyl-para-tyrosine (alpha-mpt) and diethyldithiocarbamate (ddc) on plasma growth hormone (GH) and thyrotropin (TSH) levels in hypophysectomized rats with pituitary transplants under the renal capsule. In these animals, peripheral plasma GH levels were elevated by a precursor (DOPA) and reduced by a blocker (alpha-mpt) of catecholamine synthesis. Plasma TSH levels were increased by a precursor (DOPS) and reduced by a blocker (ddc) of norepinephrine synthesis. We suspect that GH and TSH present in the circulation of pituitary-grafted animals were derived, in part, from the ectopic pituitary tissue and suggest that the small but detectable secretion of hormones other than PRL in this animal model is under the control of endogenous catecholamines.

Animals↗
PubMed1992

Ectopic aberrant adrenals with epididymal abnormality.

We report a rare case of ectopic aberrant adrenals associated with epididymal abnormality found during exploration for a left undescended testis. Two ectopic adrenals were found, one on the epididymis and the other adjacent to the spermatic cord. We believe the simultaneous occurrence of epididymal abnormality and ectopic aberrant adrenals has not been reported before.

Adrenal Glands↗
PubMed1993

Ectopic ureter presenting in midline urethral diverticulum.

A rare case of an ectopic ureter terminating in a urethral diverticulum is presented. While numerous cases of extravesical ectopic ureters draining directly into the urethra or uterovaginal canal have been reported, the termination of a ureter as a diverticular sac is extremely unusual. Moreover, only rarely has a urethral diverticulum been documented to arise congenitally due to any cause. The history and management of this new case are detailed, and the general subjects of ectopic ureter and urethral diverticulum are discussed with particular reference to etiology and continence.

Adult↗
PubMed1989

Craniofacial abnormalities induced by ectopic expression of the homeobox gene Hox-1.1 in transgenic mice.

Hox-1.1 is a murine homeobox-containing gene expressed in a time- and cell-specific manner during embryogenesis. We have generated transgenic mice that ectopically express Hox-1.1 from the chicken beta-actin promoter. In these mice Hox-1.1 expression was changed to an almost ubiquitous pattern. Ectopic expression of Hox-1.1 leads to death of the transgenic animals shortly after birth and is associated with multiple craniofacial anomalies, such as cleft palate, open eyes at birth, and nonfused pinnae. This phenotype is similar to the effects seen after systemic administration of retinoic acid during gestation. This suggests that retinoic acid embryopathy and the specific developmental defects caused by ectopic expression of a potential developmental control gene share a common pathogenic mechanism.

Abnormalities, Multiple↗
PubMed1995

Ectopic nucleolar organizer regions. A common anomaly revealed by Ag-NOR staining of metaphases from nine cancers.

In view of the sparsity of reports on nucleolar organizer regions (NORs) in human tumor metaphase chromosomes, we have applied the silver (Ag-NOR) technique to a previously studied testicular germ-cell tumor that had an abnormal translocation, which involved a 13p, and to nine new sequentially studied tumors. Six of the new tumors, and the germ cell tumor, showed ectopic NORs (e.g., at the end of the long arm of acrocentrics or metacentrics, or interstitially in metacentrics): five carcinomas and a leiomyosarcoma, all of which also revealed numerous structural chromosome changes after G-banding. The three tumors that did not show ectopic NORs were lymphomas with relatively simple karyotypic changes. It seems that the presence of ectopic NORs in the majority of the tumors is a reflection of the multiplicity of structural changes in these tumors and does not signify that there is any particular propensity for acrocentrics to take part in these changes. It was interesting that several of the chromosomes showed large notably a metacentric in a squamous cell carcinoma of the skin in which the Ag-NOR-positive region was seen as an unstained gap in unbanded and G-banded chromosomes.

Adult↗
PubMed1989

Pioneer neuron pathfinding from normal and ectopic locations in vivo after removal of the basal lamina.

The contribution of the basal lamina to Ti1 pioneer axon guidance in grasshopper limb buds was investigated by allowing growth cones to migrate in 30%-31% stage limbs from which the basal lamina had been removed by enzymatic treatment. When the Ti1 axons extended from their normal location, the pathways established in the absence of basal lamina were normal. This indicates that the basal lamina is not required for initial proximal axon outgrowth, recognition of limb segment boundaries, or selective interaction with neuronal somata. Removal of the basal lamina from slightly older (32% stage) embryos resulted in displacement of the Ti1 somata to ectopic locations in approximately 50% of the limbs. Pathfinding from ectopic locations was aberrant in 45% of the cases observed. This demonstrates that if orienting information is present in the basal lamina-free epithelium at this stage, it is not the predominant factor in determining growth cone orientation from ectopic locations.

Animals↗
PubMed1992

The development of normal and ectopic sensilla in the wings of hairy and Hairy wing mutants of Drosophila.

We have utilized enhancer trap markers to follow the development of ectopic sensillar precursors in the wings of Drosophila induced by the mutations hairy and Hairy wing. Normal sensilla are still present in these mutations, and can be distinguished from ectopic sensilla based upon both the position and the timing of their development. This correlates well with the development of ectopic achaete expression in these mutations: such staining is detected only after the appearance of normal staining. Thus, neither mutation appears to alter the specification of proneural clusters in the wing, as identified with anti-achaete, or the specification of sensillar precursors within these clusters. Rather, both act to induce the formation of a temporally and spatially distinct phase of sensillar development.

Animals↗
PubMed1996

Ectopic vasopressin expression in MMTV-v-Ha-ras transgenic mice delays the onset of mammary tumorigenesis.

Neuropeptides are often ectopically expressed by non-endocrine tumours. We used transgenic mice to assess the effect of ectopic expression of the neuropeptide, vasopressin, in mammary tumours induced by the transgenetic expression of an activated ras oncogene. Mice bearing a mouse mammary tumour virus-vasopressin (MMTV-VP) fusion transgene synthesise authentic VP in mammary ducts and alveoli. Bitransgenic mice bearing both MMTV-VP and MMTV-v-Ha-ras transgenes developed tumours that were histologically indistinguishable from those of single MMTV-v-Ha-ras animals. However, tumour onset was significantly delayed in the bitransgenic animals. These data provide evidence that an ectopic neuropeptide can slow the development of ras tumours in vivo.

Animals↗
PubMed1988

Inhibition by tumor necrosis factor of induction of ectopic bone formation by osteosarcoma-derived bone-inducing substance.

The effect of tumor necrosis factor alpha (TNF-alpha) on ectopic endochondral bone formation was studied in an experimental system for bone induction using murine osteosarcoma-derived bone-inducing substance. Ectopic new bone formation was inhibited by daily administration of recombinant human TNF-alpha (20-200 micrograms/kg body weight per day, intraperitoneally) after subcutaneous implantation of the bone-inducing substance into mice. Histological examination revealed that TNF-alpha prevented mesenchymal cells from differentiating into chondrocytes in the process of endochondral bone formation. The inhibitory effect of TNF-alpha continued during the period of its administration, but not after its administration was stopped. The bone induced in a three week period after discontinuation of TNF-alpha administration was histologically normal, but smaller than that induced in control animals. These findings suggested that TNF-alpha reversibly inhibits the biological activity of the bone-inducing substance or impairs the ability of cells to respond to the bone-inducing substance at an early stage of ectopic bone formation.

Animals↗
PubMed1990

Matrix vesicle calcification of ectopically induced osteoid tissue in 1-hydroxethylidene-1,1-bisphosphonate (HEBP)-treated mice.

The effects of 1 hydroxethylidene-1, 1-bisphosphonate (HEBP) on the mineralization of osteoid induced ectopically by a murine, osteosarcoma-derived, bone-inducing substance was examined at the ultrastructural level. Samples of Dunn osteosarcoma were chemically processed, lyophilized into pellets of uniform dimensions and protein content, and implanted into the back muscles of male, 4 week old, ddY mice. In control animals injected intraperitoneally (i.p.) with saline each day for 30 days, the pellets exhibited ectopic cartilage and bone formation in a sequential manner consistent with endochondral ossification. Daily administration of HEBP (30 mg/kg i.p. per day) to animals over the same period produced wide anastomosing strands of osteoid and haematopoietic marrow in the pellets. Electron microscopical examination revealed a tightly packed organization of collagen fibrils with many membrane bounded organelles or matrix vesicles (0.05-0.3 micron diameter) dispersed throughout this nonmineralized matrix. After withdrawal of HEBP, mineralization proceeded initially within matrix vesicles and secondarily by involvement of the surrounding collagen fibrils. In pellets retrieved at 30 days after HEBP withdrawal, most of the matrix had been mineralized and remodeled to reveal thin bony trabeculae and an overall histologic appearance similar to that seen in the control pellets. This model of ectopic bone formation permits clear visualization of the sequence of mineral nucleating events in osteoid in the absence of an established mineralizing front. The results add further support to the hypothesis that matrix vesicles are directly responsible for the initiation of mineralization in bone.

Animals↗
PubMed2006

Two cases of ectopic cervical thymus: case reports and a review of the literature.

Ectopic cervical thymic tissue has rarely been reported in the medical literature. However, it should be included in the differential diagnosis of neck masses, and especially for children. This lesion generally occurs in the descent line of the thymus from the angle of the mandible to the superior mediastinum. The preoperative diagnosis of ectopic cervical thymus is seldom considered and this is often misdiagnosed as a possible tumor or as a lymph node. We report here on two cases of ectopic cervical thymus for which the patients underwent complete excision of the masses.

Choristoma↗