Plasticity of the prolactin (PRL) axis: mechanisms underlying regulation of output in female mice.

The output of prolactin (PRL) is highly dynamic with dramatic changes in its secretion from the anterior pituitary gland depending on prevailing physiological status. In adult female mice, there are three distinct phases of output and each of these is related to the functions of PRL at specific stages of reproduction. Recent studies of the changes in the regulation of PRL during its period of maximum output, lactation, have shown alterations at both the level of the anterior pituitary and hypothalamus. The PRL-secreting cells of the anterior pituitary are organised into a homotypic network in virgin animals, facilitating coordinated bouts of activity between interconnected PRL cells. During lactation, coordinated activity increases due to the changes in structural connectivity, and this drives large elevations in PRL secretion. Surprisingly, these changes in connectivity are maintained after weaning, despite reversion of PRL output to that of virgin animals, and result in an augmented output of hormone during a second lactation. At the level of the hypothalamus, tuberoinfundibular dopamine (TIDA) neurons, the major inhibitors of PRL secretion, have unexpectedly been shown to remain responsive to PRL during lactation. However, there is an uncoupling between TIDA neuron firing and dopamine secretion, with a potential switch to enkephalin release. Such a process may reinforce hormone secretion through dual disinhibition and stimulation of PRL cell activity. Thus, integration of signalling along the hypothalamo-pituitary axis is responsible for increased secretory output of PRL cells during lactation, as well as allowing the system to anticipate future demands.

Synaptic communication mediates the assembly of a self-organizing circuit that controls reproduction.

Migration of gonadotropin-releasing hormone (GnRH) neurons from their birthplace in the nasal placode to their hypothalamic destination is critical for vertebrate reproduction and species persistence. While their migration mode as individual GnRH neurons has been extensively studied, the role of GnRH-GnRH cell communication during migration remains largely unexplored. Here, we show in awake zebrafish larvae that migrating GnRH neurons pause at the nasal-forebrain junction and form clusters that act as interhemisphere neuronal ensembles. Within the ensembles, GnRH neurons create an isolated, spontaneously active circuit that is internally wired through monosynaptic glutamatergic synapses into which newborn GnRH neurons integrate before entering the brain. This initial phase of integration drives a phenotypic switch, which is essential for GnRH neurons to properly migrate toward their hypothalamic destination. Together, these experiments reveal a critical step for reproduction, which depends on synaptic communication between migrating GnRH neurons.

Ultrasound effects.

In a listing of the new foreign associates of the National Academy of Sciences (News and Comment, 17 May, p. 826), the name of Pierre Chambon, Biochemistry, Institut de Chimie Biologique, Faculté de Médecine, Strasbourg, France, was inadvertently omitted.

Cancer mortality in a human isolate.

Cancer mortality (1965--77) among 12,652 members of an inbred human religious isolate, the Hutterites, was compared with expectations based on mortality rates for the U.S. white population in 1970. Overall, Hutterites had significantly fewer deaths from cancer than expected (P < 0.01), due primarily to fewer lung cancers among males. Smoking is prohibited for this religious group. The most frequent types of cancers were leukemia and cancers of the digestive system, the prostate gland, and the female breast. Preliminary results suggest an association between recessive alleles and childhood leukemia. More stomach and rectal cancers were observed than expected, but differences were generally not significant. Familial aggregates of cancers of the stomach and breast are being investigated. The low frequency of cervical cancer is consistent with current evidence for an association of cervical cancer with early age at first intercourse and promiscuity, neither of which is characteristic of this population.

Use of a newly established human cell line (SU-CCS-1) to demonstrate the relationship of clear cell sarcoma to malignant melanoma.

A new tumor cell line, designated SU-CCS-1, was established from the malignant pleural effusion of a 16-year-old Caucasian girl with clear cell sarcoma. Morphological studies at the light- and electron-microscopic levels revealed similar features between the SU-CCS-1 cells and the primary tumor. Ultrastructural and cytochemical techniques showed that both the SU-CCS-1 cell line and the original tumor were amelanotic in nature. The malignant derivation of the SU-CCS-1 cell line was demonstrated by intracranial and s.c. heterotransplantation in the nude, athymic mouse and by cytogenetic analysis which showed that the cell line had a hypodiploid chromosome number and several karyotypic abnormalities. Live-cell radioimmunoassay procedures using a large panel of monoclonal antibodies directed against tumor-associated antigens revealed that, phenotypically, SU-CCS-1 closely resembled melanoma tumor cell lines. Immunological assays for the detection of neuroendocrine-associated peptides, hormones, and enzymes revealed that, like melanoma, the SU-CCS-1 cell line was actively producing alpha-melanotropin, S-100 antigen, and nerve growth factor. A notable difference between these tumor types was the capacity of SU-CCS-1 to produce bombesin, an active neuropeptide whose synthesis has been found in cell lines from patients with small cell carcinoma of the lung. From these studies, we concluded that the SU-CCS-1 cell line is phenotypically similar to melanoma, yet displays unique characteristics which distinguishes it from other sarcomas. The availability of an established clear cell sarcoma cell line will greatly facilitate further studies aimed at uncovering the histogenesis of this rare cancer.

Gap junctions mediate electrical signaling and ensuing cytosolic Ca2+ increases between chromaffin cells in adrenal slices: A role in catecholamine release.

In adrenal chromaffin cells, a rise in cytosolic calcium concentration ([Ca(2+)]i) is a key event in the triggering of catecholamine exocytosis after splanchnic nerve activation. Action potential- or nicotine-induced [Ca(2+)]i transients are well described in individual chromaffin cells, but whether they remain spatially confined to the stimulated cell or propagate to adjacent cells is not yet known. To address this issue, the spatiotemporal organization of electrical and associated Ca(2+) events between chromaffin cells was investigated using the patch-clamp technique and real-time confocal imaging in rat acute adrenal slices. Spontaneous or electrically evoked action potential-driven [Ca(2+)]i transients were simultaneously detected in neighboring cells. This was likely attributable to gap junction-mediated electrotonic communication, as shown by (1) the bidirectional reflection of voltage changes monitored between cell pairs, (2) Lucifer yellow (LY) diffusion between cells exhibiting spontaneous synchronized [Ca(2+)]i transients, and (3) the reduction of LY diffusion using the uncoupling agent carbenoxolone. Furthermore, transcripts encoding two connexins (Cx36 and Cx43) were found in single chromaffin cells. This gap junctional coupling was activated after a synaptic-like application of nicotine that mediated synchronous multicellular [Ca(2+)]i increases. In addition, nicotinic stimulation of a single cell triggered catecholamine release in coupled cells, as shown by amperometric detection of secretory events. Functional coupling between chromaffin cells in situ may represent an efficient complement to synaptic transmission to amplify catecholamine release after synaptic stimulation of a single excited chromaffin cell.

The role of p53 and anaplastic lymphoma kinase genes in the progression of cutaneous CD30(+) lymphoproliferative diseases.

BACKGROUND AND OBJECTIVES: Molecular events that precede transformations from lymphomatoid palulosis (LyP) to mycosis fungoides (MF) or to cutaneous anaplastic large cell lymphoma (ALCL) in the CD 30(+) cutaneous lymphoproliferative diseases (LPDs) are not known. Altered p(53) gene may be responsible since overexpression of the p(53) gene product has been reported in higher, but not in lower grades of cutaneous lymphomas. Expression of the anaplastic lymphoma kinase (ALK) gene product has also been described as an important prognostic indicator in ALCL. ALK positive systemic nodal ALCL are associated with a good prognosis. However, primary cutaneous ALCL that are ALK negative have a better overall survival. The current study was done to see if mutated p(53) gene or ALK reactivity were poor prognostic indicators in those patients with CD 30(+) cutaneous LPD who showed progression of the disease. METHODS: Mutations of the p(53) gene and expression of the ALK gene product were analysed in 36 patients (23 of LyP and 13 of CD30(+) cutaneous ALCL). Follow up data were available up till 5 yr in all patients. RESULTS: Clinical progression or histological transformation in sequential biopsy specimens was found in 9 of 36 patients. Transformation occurred in 5 patients (4 from LyP to ALCL and 1 from MF to ALCL) and clinical progression in 4 patients with ALCL. Mutations of the p(53) gene were found in two biopsy specimens of LyP. ALK gene products were not detected in any of the biopsy specimens of LyP and primary cutaneous ALCL. INTERPRETATION AND CONCLUSION: Although 9 of 36 patients with cutaneous CD30(+) LPDs had progression of their disease, neither mutations of the p(53) gene nor ALK immunoreactivity were found in any of these biopsies. The two cases of LyP that had mutated p(53) gene in their biopsy specimens showed no progression of their disease in the 5 yr follow up period. It appears that these molecular events may not play any significant role in the pathogenesis, progression or transformation of cutaneous CD30(+) LPD.

On the selection of systems for automated cytogenetic analysis.

Impressive technological advances in systems for automated metaphase location and cytogenetic analysis have resulted in a proliferation of commercially available systems offering a variety of performance and price options. Based on the numbers of systems sold, it appears as if automation is becoming an accepted component of cytogenetic laboratories. To address the question of whether automation is useful and, if so, to identify the advantages and disadvantages of some of the systems, we have supplemented our own laboratory experience using the Magiscan routinely for clinical cytogenetic analysis, with information obtained during an on-site survey of other clinical cytogenetic facilities using automated systems (Genetiscan, Karyotype Image Editor, Metachrome, Cytoscan). Some systems provide both metaphase-locating and karyotyping capabilities--some only the latter. The basic structure of all systems is similar: microscope with camera, image processor, mechanism for operator interaction with the computer, hard copy printer. Metaphases are digitized, analyzed, and converted to permanent images. Metaphase-locating systems (Cytoscan, Magiscan, Metachrome) require, in addition, motorized slide-scanning stages. The biggest time savings resulting from use of automation is in the karyotyping steps, especially the production of a hard copy. Consequently, laboratories making many karyotypes will benefit most from such systems. The optimum choice of system will depend on specific laboratory parameters: number and type of specimens processed; operational preferences, e.g., number of bands per metaphase; number of metaphases counted; and karyotypes prepared per case. Laboratories processing chorionic villus specimens and/or bone marrows, where much slide area must be searched, will benefit from fast metaphase locators with multislide stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement of a fra(16)(q22) with distamycin A: a family ascertained through an abnormal proposita.

A family in which a fragile site at 16q22 was segregating was ascertained through a newborn infant with multiple anomalies. The same fragile site was present in the phenotypically normal father and in a brother with cleft palate. The fra(16)(q22) was similar in appearance, and in response to culture conditions, to that reported by other investigators, including increased breakage in media supplemented with distamycin A. Sampling variation in the frequency of breakage over time may be considerable in some individuals. No pattern of anomalies was found to be associated with the fragile site. However, the reproductive history of the family we report (two livebirths with major congenital anomalies and one stillbirth) suggests caution in concluding fra(16)(q22) is not deleterious.

Oculoauriculovertebral dysplasia and variants: phenotypic characteristics of 294 patients.

Here we describe the phenotypic characteristics of a single craniofacial clinic population of 294 individuals affected with oculoauriculovertebral dysplasia (OAV) and variants. To our knowledge, this is the largest population so described in the literature. The study population was divided into five subgroups based on the presence of combinations of minimal diagnostic criteria: microtia, mandibular hypoplasia, anomalies of the cervical spine and/or epibulbar or lipodermoids. The following data were recorded: sex (M:F 191:103); race (78% Caucasian); the presence of unilateral or bilateral microtia (193 unilateral, 98 bilateral); the presence of symmetric microtia in bilateral cases (34/98); the presence of mandibular hypoplasia ipsilateral or contralateral to the microtic ear or most severely microtic ear in bilateral cases (135/137 were ipsilateral in unilateral cases, 55/62 were ipsilateral in bilateral cases); the number of individuals with no other congenital anomaly in addition to the minimal diagnostic criteria (154/294), with only one other congenital anomaly (51/294), and with two or more other congenital anomalies (89/294); and the type of other congenital anomalies. Finally, we compared our results with other studies. Findings from our study include: mandibular asymmetry should be expected in patients with unilateral or bilateral microtia; bilateral involvement is frequent in patients with microtia; other malformations are seen frequently in all subgroups; anomalies of the cervical spine are more likely to be associated with other anomalies; and other malformations are seen in all systems and should be searched for to provide optimal management.

Oculoauriculovertebral anomaly: segregation analysis.

Seventy-four families of probands with oculoauriculovertebral anomaly were evaluated, including 116 parents and 195 offspring. Relatives were examined to identify ear malformations, mandibular anomalies, and other craniofacial abnormalities. For segregation analysis using POINTER, selection of the sample was consistent with single ascertainment. Different population liabilities were used for probands and relatives, because affection was narrowly defined for probands and broadly defined for relatives. The hypothesis of no genetic transmission was rejected. The evidence favored autosomal dominant inheritance; recessive and polygenic models were not distinguishable.

Microtia and associated anomalies: statistical analysis.

Terms such as oculoauriculovertebral dysplasia, Goldenhar syndrome, and hemifacial microsomia have been used to describe microtia with specific combinations of other craniofacial anomalies. Microtia is also observed with anomalies of postcranial structures. Statistical studies were performed on 297 patients with microtia and other anomalies to identify subgroups of patients representing previously described or new associations. Analysis identified 15 subgroups of patients with specific patterns of anomalies. Log-linear analyses of cranial and postcranial variables demonstrated a positive association between mandibular hypoplasia and cervical spine fusion, which was, in turn, positively associated with other spine anomalies (P less than .02) and other skeletal anomalies (P less than .001). Although unilateral microtia was commonly observed with mandibular hypoplasia, mandibular hypoplasia was negatively associated with bilateral microtia. Many of the associated anomalies were of structures not derived from the 1st and 2nd branchial arch neural crest. However, most associated anomalies were of structures derived from migratory cell populations or populations undergoing differentiation prior to migration between the 19th and 24th day post-fertilization (neural crest, ectodermal placode, mesoderm, surface ectoderm). These findings suggest that many different cell populations may be disturbed in the pathogenesis of microtia in association with other anomalies. The timing of the pathogenetic event may determine the specific pattern of associated anomalies.

Prenatal detection of 46,XY,rec(5),dup q, inv(5)(p13q33) using DNA analysis, flow cytometry, and in situ hybridization to supplement classical cytogenetic analysis.

Distinguishing between balanced and unbalanced chromosome complements segregating from parental rearrangements may be difficult using only classical cytogenetic techniques if banding morphology is similar under both expectations. In these situations, supplementing cytogenetic analysis with molecular genetic techniques and flow cytometry may provide increased diagnostic accuracy. To illustrate this, we present a case in which similar band pattern morphology would be expected for both the balanced carrier (heterozygote) and the recombinant dup q chromosome complements segregating from a mother with a balanced inversion [46,XX,inv(5)(p13q33)]. The parents came to Northwestern for consultation after receiving conflicting interpretations of their first amniotic fluid cultures. An ultrasound examination was said to be normal. They inquired whether there were ways to increase their confidence that the complement was unbalanced. Their reluctance to terminate the pregnancy was due to a 6-year history of infertility. After extensive counselling, the couple elected repeat amniocentesis. Further cytogenetic analysis of repeat amniotic fluid cultures by G-banding and R-banding, molecular genetic analysis with highly polymorphic DNA probes, and quantitative flow cytometry were performed. Results agreed that an unbalanced fetal complement was present. Southern blot analysis with a 5p marker definitively demonstrated a lack of maternal 5p material in the fetus, and in situ hybridization showed a 5q marker at either end of the recombinant chromosome. Flow cytometry was consistent with this interpretation. Because of the advanced gestational age, the parents elected to terminate based on cytogenic results of the second amniocentesis, rather than to wait another 1-2 weeks for results of other methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Parental chromosomal rearrangements associated with repetitive spontaneous abortions.

Parental chromosomal rearrangements represent a well-established cause of repetitive spontaneous abortions. However, the frequent of parental translocations varies widely in reported series, suggesting differences in ascertainment. For this reason a sample of individuals (120 women, 104 men) who had experienced spontaneous abortions but neither stillborn nor anomalous liveborn infants was investigated. Only one translocation was detected (0.4% of individuals). The relatively low frequency of translocations in this series of probably a reflection of not only lack of coexisting stillborn or anomalous infants but also the referral pattern in this unit that facilitates routine analysis of all couples experiencing repetitive abortions. In addition, one women showed a pericentric inversion.

Hypermodal cells, hypomodal cells, and repetitive abortions.

The frequency of neither hypermodal cells (2N = 47) nor hypomodal cells (2N = 45) differed between lymphocytes of individuals experiencing repetitive spontaneous abortions (N = 429) and controls (N = 90). The same conclusion held when data were analyzed according to chromosome involved (sex chromosome, autosome) or other variables (e.g., prior reproductive outcome). A study of this relatively large sample failed to confirm findings of smaller and sometimes uncontrolled studies. Hypermodal cells do not necessarily serve as a clue to meiotic instability and in turn probably do not identify couples at risk for recurrent aneuploidy.

Translocations are infrequent among couples having repeated spontaneous abortions but no other abnormal pregnancies.

During the years 1977 to 1986, cytogenetic studies were performed on 342 women and 297 men whose reproductive history included one or more first trimester spontaneous abortions. Thirty-nine women and 35 men experienced not only early fetal losses but also one or more stillborn infants, liveborn anomalous infants, or early neonatal deaths. Among the 303 women and 262 men evaluated solely because of repetitive abortions, only 1 woman and 1 man showed a translocation. Two translocations were detected among the 39 women and 35 men having not only repetitive abortions but also a stillborn infant, anomalous liveborn, or unexplained neonatal death. Only among the 25 women having abortions and other abnormal perinatal events was the frequency of translocations high (2/25 or 8%). Our data continue to indicate that balanced chromosomal translocations are relatively infrequent in individuals having repeated abortions but no other adverse perinatal outcome.

Adverse effects of human leukocyte antigen-DR sharing on fertility: a cohort study in a human isolate.

To elucidate further the reproductive effects of human leukocyte antigen (HLA) sharing among spouses, we have been investigating prospectively the relationship between HLA-A, -B, and -DR sharing and reproductive outcome in the Hutterites, a religious isolate that proscribes contraception. For the first time the reproductive effects of HLA-DR sharing in a fertile population is reported in this article. Median intervals from marriage to first through fifth births were longer among couples who shared more than one HLA-A, -B, or -DR antigen. Longer intervals were associated with increased spontaneous abortion rates among couples who shared HLA-DR antigens (27%), compared with couples who shared only HLA-A or -B antigens (9%) and couples who shared no antigens (12%). Median completed family sizes were 5.0, 8.5, and 8.0 among the groups, respectively. However, some couples who shared HLA-DR antigens experienced no spontaneous abortions, despite ten or more pregnancies. Therefore, although HLA-DR compatibility, per se, is not deleterious, our data suggest a potentially important role for undefined HLA-linked genes in normal pregnancy.

The value of scatter removal by a grid in full field digital mammography.

Our objective in this study was to investigate the usefulness of an anti-scatter grid in digital mammography using a contrast detail phantom. The mammography system we investigated was a GE Senographe 2000D. We carried out phantom measurements under various conditions with and without using the anti-scatter grid. A new version of the CDMAM phantom (version 3.4) was used. This phantom consists of a matrix of square cells with disks of varying size and contrast. For given exposure conditions detectability of these disks can be determined and used for construction of contrast detail curves. Previously, a computer program was developed at our institute that performs a fully automatic analysis of the phantom recordings using the ideal observer model. Breast thickness was simulated by a homogeneous layer of PMMA in the range of 1 to 7 cm. Series of images were recorded for different KeV and target-filter combinations depending on the simulated thickness. The dose was kept constant for each thickness with and without using a grid. It appeared that image quality improved for simulated breast thickness below 5 cm when the grid was removed. In the range from 5 to 7 cm contrast detail curves obtained with or without a grid were similar. Results suggest that for compressed breast thickness in the range of 1 to 7 cm a grid might not be needed in the digital mammography system we investigated. Below 5 cm, omitting the grid may allow lower dose to the patient without losing image quality.

A critical review of the genotoxic potential of electric and magnetic fields.

55 published articles were identified which reported results of tests of ELF (extremely low frequency) or static electric or magnetic fields for genotoxic effects. The biological assays used spanned a wide range, including microbial systems, plants, Drosophila, mammalian and human cells in vitro and in vivo. Experimental results were grouped into four exposure categories: ELF Electric; ELF Magnetic; Static Electric; and Static Magnetic. The internal electric fields present in media (for in vitro experiments) and in the torso and extremities (for in vivo experiments) were estimated, providing an index of comparison. All experiments were critically analyzed with respect to basic data quality criteria. Experiments within each exposure category were then compared to determine if results reinforced or contradicted one another. The preponderance of evidence suggests that neither ELF nor static electric or magnetic fields have a clearly demonstrated potential to cause genotoxic effects. However, there may be genotoxic activity from exposure under conditions where phenomena auxiliary to an electric field, such as spark discharges, electrical shocks, or corona can occur. In addition, two unconfirmed reports suggest the genotoxic potential of certain chemical mutagens or ionizing radiation may be affected by co-exposure to electric or magnetic fields. Certain exposure categories are not represented or are under-represented by tests in some genotoxicity test systems that are usually included in minimal test batteries as specified by EPA for chemicals. It is suggested that consideration be given to whether additional genotoxicity testing is warranted to fill these gaps.

Cytogenetic analysis of a case of "13q- syndrome" (46,XX,del 13) using banding techniques.

Many chromosomal syndromes include ocular anomalies. In the del(13q) syndrome retinoblastoma, coloboma, and microphthalmia may be present. In the del(13q) case we report, the findings include colobomas and apparent microphthalmia, although the retinoblastoma sometimes associated with this condition was not observed. More precise descriptions of the del(13q) syndrome relative to the region deleted using improved banding techniques may: (1) increase the likelihood of accurate diagnosis, (2) enhance clinical predictions, and (3) possibly further clarify the genetic control over the development of the ocular system.