Colgajo de Mustardé como tratamiento de un carcinoma basocelular. A propósito de un caso

Introducción: El carcinoma basocelular es actualmente el cáncer de piel más frecuente, siendo su principal factor de riesgo la exposición a radiación ultravioleta. Su tratamiento es la resección quirúrgica, según riesgo de recurrencia. La reconstrucción facial posterior a la resección se enfrentará según la unidad estética de la cara, lo cual determinará la técnica quirúrgica a utilizar. Material y Método: El siguiente caso clínico aborda la resección de un carcinoma basocelular nodular morfeiforme ubicado en mejilla y ala nasal, y posterior reconstrucción mediante el uso de un Colgajo de Mustardé, con resultado exitoso. Resultados: Evolución favorable, con reseccion completa de la lesion tumoral y vitalidad del colgajo postoperatorio. Cursó con una leve desviación nasal que cedió con masaje de la cicatriz. Se puede plantear una plastía de retoque del ala nasal a futuro. Conclusión: Presentamos un caso clínico de un carcinoma basocelular facial con alto riesgo de recurrencia que fue tratado en forma segura y efectiva con un colgajo de Mustardé.

Introduction: Basal-cell carcinoma is currently the most frequent type of skin cancer, its main risk factor being exposure to ultraviolet radiation. Treatment consists of surgical resection, according to recurrence risk. Post-resection facial reconstruction should be faced according to the aesthetic unit of the face, which will determine the surgical technique. Material and Method: The following clinical case presents the resection of a morpheiform nodular basal-cell carcinoma located on the cheek and nasal wing, and subsequent reconstruction using a Mustarde flap, with successful results. Results: Favorable evolution with complete resection of the tumor lesion and postoperative vitality of the flap. The patient presented a slight nasal deviation that resolved with scar massage. A nasal wing plasty can be considered in the future. Conclusion: We present a facial basal-cell carcinoma clinical case that was safely and effectively treated with a Mustarde flap.

[Comparison of tiapride and topiramate in the prophylactic treatment of chronic migraine: a randomised, double-blind, pilot study]. / Comparación de la tiaprida y el topiramato en el tratamiento profiláctico de la migraña crónica: estudio piloto, aleatorizado y doble ciego.

AIM: The aim of this study was to evaluate the efficacy and safety of tiapride compared to topiramate as a prophylactic in chronic migraine. PATIENTS AND METHODS: The study was conducted under randomised and double blind conditions. A total of 56 patients aged 18-65 years with chronic migraine were assigned to two treatment arms: tiapride, 100 mg twice daily, or topiramate, 25 mg twice daily, for 12 weeks. The primary endpoint was the change in the monthly average number of migraine days. In addition, measurements were performed to determine the change in the monthly number of headache days, the percentage of subjects with >50% and >75% decrease in their monthly migraine days, and the change in headache impact as measured by the Headache Impact Test-6. RESULTS: The intention-to-treat population included 39 subjects (tiapride = 21; topiramate = 18), 35 of whom (tiapride = 18; topiramate = 16) completed the trial. The tiapride group had a mean reduction of 7.2 ± 7.5 migraine days per month compared to 7.6 ± 5.8 for the topiramate group (p = 0.86). As with the other efficacy variables measured, no differences were found between the two groups. Adverse side effects were mild in both groups. CONCLUSION: In patients with chronic migraine, tiapride was found to be an effective, safe and well-tolerated prophylactic treatment when compared to topiramate.

TITLE: Comparación de la tiaprida y el topiramato en el tratamiento profiláctico de la migraña crónica: estudio piloto, aleatorizado y doble ciego.Objetivo. Evaluar la eficacia y la seguridad de la tiaprida en comparación con el topiramato en la profilaxis de la migraña crónica. Pacientes y métodos. Es un estudio aleatorizado y doble ciego. Un total de 56 pacientes de 18 a 65 años con migraña crónica fueron asignados a dos brazos de tratamiento: tiaprida, 100 mg dos veces al día, o topiramato, 25 mg dos veces al día, durante 12 semanas. El criterio de valoración principal fue el cambio en el promedio mensual de días de migraña. Además, se midió el cambio en el número mensual de días de cefalea, el porcentaje de sujetos con disminución > 50% y > 75% de sus días de migraña mensual, y el cambio del impacto de la cefalea medido por el Headache Impact Test-6. Resultados. La población por intención de tratar incluyó a 39 sujetos (tiaprida = 21; topiramato = 18) y completaron el ensayo 35 participantes (tiaprida = 18; topiramato = 16). El grupo con tiaprida tuvo una reducción media de 7,2 ± 7,5 días con migrañas por mes en comparación con 7,6 ± 5,8 para el grupo con topiramato (p = 0,86). Al igual que en las otras variables de eficacia medidas, no hubo diferencias significativas entre ambos grupos. Los efectos adversos fueron leves en ambos grupos. Conclusión. En pacientes con migraña crónica, la tiaprida demostró ser un tratamiento profiláctico eficaz, seguro y bien tolerado, al compararla con el topiramato.

Comparación de la tiaprida y el topiramato en el tratamiento profiláctico de la migraña crónica: estudio piloto, aleatorizado y doble ciego / Comparison of tiapride and topiramate in the prophylactic treatment of chronic migraine: a randomised, double-blind, pilot study

Objetivo: Evaluar la eficacia y la seguridad de la tiaprida en comparación con el topiramato en la profilaxis de la migraña crónica. Pacientes y métodos: Es un estudio aleatorizado y doble ciego. Un total de 56 pacientes de 18 a 65 años con migraña crónica fueron asignados a dos brazos de tratamiento: tiaprida, 100 mg dos veces al día, o topiramato, 25 mg dos veces al día, durante 12 semanas. El criterio de valoración principal fue el cambio en el promedio mensual de días de migraña. Además, se midió el cambio en el número mensual de días de cefalea, el porcentaje de sujetos con disminución > 50% y > 75% de sus días de migraña mensual, y el cambio del impacto de la cefalea medido por el Headache Impact Test-6. Resultados: La población por intención de tratar incluyó a 39 sujetos (tiaprida = 21; topiramato = 18) y completaron el ensayo 35 participantes (tiaprida = 18; topiramato = 16). El grupo con tiaprida tuvo una reducción media de 7,2 ± 7,5 días con migrañas por mes en comparación con 7,6 ± 5,8 para el grupo con topiramato (p = 0,86). Al igual que en las otras variables de eficacia medidas, no hubo diferencias significativas entre ambos grupos. Los efectos adversos fueron leves en ambos grupos. Conclusión: En pacientes con migraña crónica, la tiaprida demostró ser un tratamiento profiláctico eficaz, seguro y bien tolerado, al compararla con el topiramato.(AU)

Aim: The aim of this study was to evaluate the efficacy and safety of tiapride compared to topiramate as a prophylactic in chronic migraine. Patients and methods: The study was conducted under randomised and double blind conditions. A total of 56 patients aged 18-65 years with chronic migraine were assigned to two treatment arms: tiapride, 100 mg twice daily, or topiramate, 25 mg twice daily, for 12 weeks. The primary endpoint was the change in the monthly average number of migraine days. In addition, measurements were performed to determine the change in the monthly number of headache days, the percentage of subjects with >50% and >75% decrease in their monthly migraine days, and the change in headache impact as measured by the Headache Impact Test-6. Results: The intention-to-treat population included 39 subjects (tiapride = 21; topiramate = 18), 35 of whom (tiapride = 18; topiramate = 16) completed the trial. The tiapride group had a mean reduction of 7.2 ± 7.5 migraine days per month compared to 7.6 ± 5.8 for the topiramate group (p = 0.86). As with the other efficacy variables measured, no differences were found between the two groups. Adverse side effects were mild in both groups. Conclusion. In patients with chronic migraine, tiapride was found to be an effective, safe and well-tolerated prophylactic treatment when compared to topiramate.(AU)

The Calcium-Sensing Receptor in Health and Disease.

The extracellular calcium-sensing receptor (CaSR) is a unique G protein-coupled receptor (GPCR) activated by extracellular Ca2+ and by other physiological cations including Mg2+, amino acids, and polyamines. CaSR is the most important master controller of the extracellular Ca2+ homeostatic system being expressed at high levels in the parathyroid gland, kidney, gut and bone, where it regulates parathyroid hormone (PTH) secretion, vitamin D synthesis, and Ca2+ absorption and resorption, respectively. Gain and loss of function mutations in the CaSR are responsible for severe disturbances in extracellular Ca2+ metabolism. CaSR agonists (calcimimetics) and antagonists (calcilytics) are in use or under intense research for treatment of hyperparathyroidism secondary to kidney failure and hypocalcemia with hypercalciuria, respectively. Expression of the CaSR extends to other tissues and systems beyond the extracellular Ca2+ homeostatic system including the cardiovascular system, the airways, and the nervous system where it may play physiological functions yet to be fully understood. As a consequence, CaSR has been recently involved in different pathologies including uncontrolled blood pressure, vascular calcification, asthma, and Alzheimer's disease. Finally, the CaSR has been shown to play a critical role in cancer either contributing to bone metastasis and/or acting as a tumor suppressor in some forms of cancer (parathyroid cancer, colon cancer, and neuroblastoma) and as oncogene in others (breast and prostate cancers). Here we review the role of CaSR in health and disease in calciotropic tissues and others beyond the extracellular calcium homeostatic system.

Susceptibility of preparasitic stages of Chordodes nobilii (Gordiida, Nematomorpha) to the fungicide carbendazim.

We evaluated the effect of carbendazim on non-target organisms using the parasite Chordodes nobilii as a test organism. The Gordiida act as a link between freshwater and terrestrial ecosystems; and C. nobilii, a neotropical representative species of this group, has been shown to be sensitive to other contaminants even at environmentally acceptable concentrations. The taxa susceptible to carbendazim, however, may not be adequately represented among the standard aquatic test species used in ecotoxicological risk assessment. Moreover, the autochthonous organisms in this area that could be used as bioindicators still need to be found. The aim of the present work was therefore to assess the susceptibility of the preparasitic stages of C. nobilii to noxious effects by carbendazim. The assay protocol consisted in 96- and 48-h acute exposures of early embryonic stages and larvae, respectively, to concentrations ranging from 10 to 360 µg/l. Embryonic development was not inhibited by carbendazim at any of the evaluated concentrations, but the infectivity of larvae emerging from the exposed eggs was significantly diminished. Larval survival rate was also affected at the lowest concentration assayed. Values of the mean inhibition concentration (IC50) were 7 and 11 µg/l for embryos and larvae, respectively. Compared to other freshwater organisms, C. nobilii can be considered a species moderately to highly susceptible to carbendazim. As the expected environmental concentrations of carbendazim range from 6.25 to 41.3 µg/l, C. nobilii could well be a species in danger when exposed to this fungicide.

“Comparación de técnicas de laboratorio para el diagnóstico de Giardia intestinalis” / “Comparison of Laboratory Techniques For the Diagnosis of Giardia Intestinalis”

Evaluar la sensibilidad y especificidad de tres técnicas de laboratorio para el diagnóstico de Giardia intestinalis. Materiales y Métodos: 31 muestras de heces provenientes de niños en edad preescolar, se procesaron a través del examen microscópico con SSF-lugol, método de concentración de Ritchie y método inmunológico “Giardia-Strip”. La Técnica de Ritchie fue considerada como “Gold Standard”. Resultados: Se identificaron quistes de Giardia intestinalis en 6 muestras (19,35%) a través de la técnica de Ritchie. La técnica del examen al fresco identificó en 5 de ellas quistes del protozoario (16,1%), mostrando una sensibilidad de 83% y especificidad del 100%. La técnica Giardia-Strip identificó quistes en 4 muestras (12,9%) con sensibilidad de 66,66% y especificidad del 100%. El valor predictivo positivo para el método de “Giardia-Strip” fue 14% y valor predictivo negativo de 93%. El examen al fresco mostró valor predictivo positivo del 100% y valor predictivo negativo de 96%. Conclusiones: El concentrado de Ritchie y el examen al fresco mostraron mayor sensibilidad y especificidad en el diagnóstico de Giardia intestinalis, cuando las muestras contienen solo quistes. Sin embargo, el método Giardia-Strip, demostró mayor rapidez en la obtención de los resultados.

Objective: To evaluate the sensitivity and specificity of three laboratory techniques for the diagnosis of Giardia intestinalis. Materials and Methods: 31 fecal samples from preschoolers were submitted to microscopic examination with SSF-Lugol, the Ritchie concentration method and the “Giardia-Strip” immunological method. The Ritchie technique was considered the “gold standard.“ Results: G. intestinalis cysts were identified in 6 samples (19.35%) using the Ritchie technique. The fresh test identified 5 cases of protozoan cysts (16.1%), showing a sensitivity of 83 % and specificity of 100 %. The Giardia-Strip identified cysts in 4 samples (12.9%) with 66.66 % sensitivity and 100% specificity. The positive predictive value for the “Giardia Strip” method was 14% and the negative predictive value was 93%. The fresh test showed a positive predictive value of 100% and a negative predictive value of 96 %. Conclusions: Ritchie concentrate and the fresh test showed higher sensitivity and specificity in the diagnosis of Giardia intestinalis, when samples contain only cysts. However, the Giardia-Strip method proved faster in obtaining results.

Periodontal regeneration following implantation of cementum and periodontal ligament-derived cells.

BACKGROUND AND OBJECTIVE: The periodontal regeneration of bone defects is often unsatisfactory and could be largely improved by cell therapy. Therefore, the purpose of this study was to evaluate the regenerative potential of implanting canine cementum-derived cells (CDCs) and canine periodontal ligament-derived cells (PDLDCs) in experimentally created periodontal intrabony defects in beagle dogs. MATERIAL AND METHODS: Cells were obtained from premolars extracted from four beagle dogs. Three-wall intrabony periodontal defects, 3 mm wide and 4 mm deep, were surgically created in their second and fourth premolars and plaque was allowed to accumulate. Once the defects were surgically debrided, periodontal regeneration was attempted by random implantation of collagen sponges embedded with 750,000 CDCs, 750,000 PDLDCs or culture medium. After 3 mo of healing, specimens were obtained and periodontal regenerative outcomes were assessed histologically and histometrically. RESULTS: The histological analysis showed that a minimal amount of new cementum was formed in the control group (1.56 ± 0.39 mm), whereas in both test groups, significantly higher amounts of new cementum were formed (3.98 ± 0.59 mm in the CDC group and 4.07 ± 0.97 mm in the PDLDC group). The test groups also demonstrated a larger dimension of new connective tissue, resulting in a significantly more coronal level of histological attachment. CONCLUSION: This proof-of-principle study suggests that cellular therapy, in combination with a collagen sponge, promoted periodontal regeneration in experimental intrabony periodontal defects.

Sexual size dimorphism, sex ratio and the relationship between seasonality and water quality in four species of Gordiida (Nematomorpha) from Catamarca, Argentina.

A total of 687 adult nematomorphs of four species of Gordiida: Chordodes brasiliensis (393 specimens), Noteochorododes cymatium (47 specimens), N. talensis (162 specimens) and Pseudochordodes dugesi (85 specimens) were collected during a period of 1 year from El Simbolar stream, Argentina. Free-living worms were abundant during autumn and spring, but their number decreased during winter and summer. Males were shorter and significantly more abundant than females. The presence of N. cymatium, N. talensis and P. dugesi was correlated with water temperature and these species were most abundant in winter and spring. The presence of C. brasiliensis was correlated with flow rate and pH; this species was more abundant in autumn and winter. These four species are sympatric.

Resultados generales del Proyecto INTRA-OMS en Chile / Results of the INTRA-WHO survey in Chile

Background: The aging speed in developing countries has been faster than predicted. Thus, health care systems must adapt to face this new scenario efficiently. The WHO designed the INTRA study to assess health promotion and protection actions in primary care, for people over 50 years of age. Material and methods: Questionnaries designed by WHO were applied to 1,167 subjects (aged 50-94 years, 68percent female) and 117 health care professionals attending and working respectively, at 33 health care centers of the Viña-Quillota Health Service. Results: Twenty percent of subjects were illiterate and 25percent had less than 6 years of instruction. Forty three percent could reache the health centre by public transportation and 92percent did not need to be accompanied, 39percent spended more than one hour to be attended and 71percent considered that the service in the centre was good. Sixty seven percent attended regular appointments, 63percent did not perform any physical activity and only half of them were advised to start such activity. Weight loss was recommended to 55percent but only one third has achieved such goal. Only one third of patients admitted being interrogated about their drinking habits. Among subjects in whom blood pressure was measured, one fourth had abnormal values. Conclusions: Primary health care in Chile, although having health care programs for the elderly, is loosing opportunities to improve health status and quality of life of this age group.

Scanning electron microscopy and intraspecific variation of Chordodes festae Camerano, 1897 and C. peraccae (Camerano, 1894) (Nematomorpha: Gordioidea).

The nematomorph species Chordodes festae Camerano, 1897 and C. peraccae (Camerano, 1894) are redescribed by using scanning electron microscopy (SEM). C. festae has a cuticle with four different areolar types, the crown areoles being the most noticeable with long spiniform processes. The terminal end in the male specimen has two short lobe-like structures and a ventral groove. C. peraccae has three areolar types in which, as in C. festae, some areoles form groups surrounding the crown areoles. Intraspecific variations were found in body length and body colour in both species and, in C. peraccae, also in the cuticle.

Mitochondrial [Ca(2+)] oscillations driven by local high [Ca(2+)] domains generated by spontaneous electric activity.

Mitochondria take up calcium during cell activation thus shaping Ca(2+) signaling and exocytosis. In turn, Ca(2+) uptake by mitochondria increases respiration and ATP synthesis. Targeted aequorins are excellent Ca(2+) probes for subcellular analysis, but single-cell imaging has proven difficult. Here we combine virus-based expression of targeted aequorins with photon-counting imaging to resolve dynamics of the cytosolic, mitochondrial, and nuclear Ca(2+) signals at the single-cell level in anterior pituitary cells. These cells exhibit spontaneous electric activity and cytosolic Ca(2+) oscillations that are responsible for basal secretion of pituitary hormones and are modulated by hypophysiotrophic factors. Aequorin reported spontaneous [Ca(2+)] oscillations in all the three compartments, bulk cytosol, nucleus, and mitochondria. Interestingly, a fraction of mitochondria underwent much larger [Ca(2+)] oscillations, which were driven by local high [Ca(2+)] domains generated by the spontaneous electric activity. These oscillations were large enough to stimulate respiration, providing the basis for local tune-up of mitochondrial function by the Ca(2+) signal.

Aflatoxin synthesis in corn fields in Guanajuato, Mexico.

Aflatoxin contamination of corn is an important problem internationally, particularly in tropical and subtropical conditions that favor infection and synthesis by Aspergillus. Environmental conditions (drought) and agronomic practices i.e. N fertilization have been reported as favorable to aflatoxin synthesis in the field. This study was undertaken to investigate whether the contamination of corn commonly observed in stored conditions in this important corn producing region of Mexico known as "El Bajio" is related to infection by Aspergillus under field conditions. Results using three corn hybrids of recognized susceptibility to infection showed that corn ears artificially inoculated in the field with a toxigenic strain of Aspergillus parasiticus presented a low content of aflatoxin ranging from 13.6 to 24.7 microg Kg(-1). No significant differences were observed between the hybrids tested. Similarly, N fertilization practices, 260 Kg N ha(-1), applied at sowing did not have an effect on the extent of the contamination observed of 6.2 and 19.3 mg of aflatoxin kg(-1) in natural infected and inoculated samples with A. parasiticus NRRL 2999, respectively. Our data suggest that the cases of aflatoxin contamination of corn in this part of Mexico are not related to infection occurring during the crops growing period but most probably to poor storage conditions of corn.

The relationship between pulsatile secretion and calcium dynamics in single, living gonadotropin-releasing hormone neurons.

It is well established that pulsatile release of GnRH regulates the reproductive axis, but little is known about the mechanisms underlying this pulsatility. Recent findings that GT1 cells, a line derived from the mouse embryonic hypothalamus, release GnRH in a pulsatile manner indicates that this rhythmic activity is an intrinsic property of GnRH neurons. In several attempts to uncover the intracellular basis for this pulsatile phenomenon, it was revealed that intracellular calcium concentrations change in a rhythmic fashion in GnRH neurons and that cellular depolarization, which triggers a secretory event, is associated with profound calcium changes in the cells. These findings raised the intriguing possibility that periodic alterations in intracellular calcium concentrations may underlie the phenomenon of pulsatile secretion in GnRH neurons. To address this, we first adapted the use of FM1-43 fluorescence to monitor changes of secretion in individual GT1-7 cells and then combined this approach with simultaneous measurement ofintracellular free calcium ([Ca2+]i, fura 2 method). In initial validation experiments, we found that stimulation of exocytosis with K+ (75 mM) or N-methyl-D-aspartate (NMDA, 100 microM) predictably evoked dynamic increases of both FM1-43 and fura 2 fluorescence. Later measurement of calcium dynamics and exocytotic activity in unstimulated cells revealed that [Ca2+]i underwent transitions from quiescence to high oscillatory behavior, and that these shifts were frequently associated with exocytotic events. Moreover, these calcium oscillatory transitions and associated changes in secretory activity occurred synchronously among most adjacent cells and at a frequency similar to that reported for pulsatile release of GnRH by entire cultures of GnRH neurons. Taken together, these results indicate that the intrinsic secretory pulsatility of GnRH neurons appears to be a consequence of coordinated, periodic changes in the pattern of calcium oscillations within individual cells.

Description of Gordionus porosus n. sP. and redescription of Gordionus ondulatus (Nematomorpha, parachordodinae) with scanning electron microscopy.

Two hairworms from Argentina, Gordionus porosus n. sp. and Gordionus ondulatus (Nematomorpha, Gordioidea), are described and illustrated. The cuticle of both species shows only 1 areolar type. Areoles of G. porosus are polygonal and surrounded by minute bristles and the interareolar groove is wide and with large pores. Gordionus ondulatus is characterized by rectangular or irregular areoles from which margins cuticular elongations project as finger-like structures, giving an undulated appearance. Comparing these species to the remaining American species of Gordionus, G. porosus is close to Gordionus violaceus by virtue of the large number of small bristles surrounding the areoles and can be distinguished by the shape of these bristles and by the arrangement and shape of the areoles. Gordionus ondulatus differs from the other species of the genus by its undulating margins. Giordinus lineatus and Giordinus violaceus have been reported in North America, Giordinus platycephalus in North and Central America, Giordinus capitosulcatus in Central America, and Giordinus prismaticus, G. ondulatus, and G. porosus only in South America.

Dynamics of stimulus-expression coupling as revealed by monitoring of prolactin promoter-driven reporter activity in individual, living mammotropes.

Single-cell paradigms have greatly expanded our knowledge about stimulus-secretion coupling, but the understanding of stimulus-gene expression coupling has lagged behind for lack of a dynamic model sufficiently sensitive to provide single-cell resolution. In the present study, we made continuous indirect measurements within individual, living cells of expression dynamics both before and after treatment with a gene-activating secretagogue. This was accomplished by transfecting (via microinjection) individual, primary mammotropes with a PRL promoter-driven luciferase reporter plasmid, and then quantifying the rate of photonic emissions (reflective of endogenous gene activity). We found that individual cells exhibit spontaneous, random, short-term fluctuations of basal reporter activity and are extremely heterogeneous in terms of responses to a stimulatory agent (TRH). In addition, we found that responses are affected by several factors including the secretory status of the pituitary donor, the manner in which the stimulus is presented, and by the initial level of reporter activity. Moreover, the responsiveness of an individual cell can fluctuate dramatically over time. These results invite speculation that a given cell can "sense" its gene activation state and regulate its response accordingly to satisfy requirements for the corresponding secretory product.

Differential influences of gender and physiological status on calcium dynamics and prolactin gene expression in rat mammotropes.

The rate of prolactin (PRL) secretion is influenced by the gender and physiological state of an animal, but little is known about the mechanisms involved. In the present study, we assessed possible contributions of Ca2+ dynamics and PRL gene expression to these differences. This was accomplished by monitoring spontaneous [Ca2+]i changes and PRL promotor-driven reporter activity in pituitary cultures derived from rats comprising a broad spectrum of PRL secretory capacities: male, cycling female, and lactating rats. We found that Ca2+ oscillatory activity exhibited a rank order of lactating > cycling females > males, consistent with the reported secretory capacities of mammotropes from these sources. Interestingly, we observed that the basal level of PRL promotor-driven reporter activity was the same for all three models, but that mammotropes from males were the most responsive to stimulation of PRL gene expression by elevation of [Ca2+]i. Collectively, our findings reveal gender- and state-specific differences in Ca2+ dynamics and induction of PRL gene expression. These likely contribute to reported differences in secretory capacity.

Effects of cellular interactions on calcium dynamics in prolactin-secreting cells.

Signals derived from other pituitary cells can have a dramatic effect on PRL gene expression and secretion by mammotropes. However, the intracellular mechanisms by which these effects are manifested on the target cell remain unexplored. Inasmuch as calcium is a key modulator of both gene expression and hormone export in mammotropes, we evaluated the effects of cell to cell contact vs. specific cellular interactions on calcium dynamics within these cells. This was accomplished by digital-imaging fluorescence microscopy of fura-2 in pituitary cells that were isolated in culture (singles) or adjoining one other cell (doublets). After calcium imaging, we then subjected cells to immunocytochemistry for PRL. Doublets were further categorized into mammotropes attached to another mammotrope (M-M) or to a nonmammotrope (M-nonM). We then calculated and compared Mean [Ca2+]i values as well as Oscillation Indices (which reflect the oscillatory behavior of cells) in singles and doublets and found that they were not different (P > 0.05). However, the phenotype of the adjoining cell had a profound influence on both of these calcium parameters, such that the presence of one mammotrope could consistently decrease (P < 0.05) the Mean [Ca2+]i value (39.17 +/- 3.83 vs. 56.24 +/- 5.56 in M-nonM) and Oscillation Index (10.19 +/- 1.76 vs. 21.21 +/- 3.73 in M-nonM) of its neighboring counterpart. A more detailed analysis of oscillatory patterns in these cells revealed that nonoscillators were more abundant in M-M (23%) than in M-nonM (12%) doublets. Taken together, our results indicate that PRL-secreting cells convey a signal that dampens the oscillatory behavior of neighboring mammotropes. Thus, it appears that it is the phenotype rather than the physical presence of a neighbor that controls intercellular regulation of calcium dynamics among mammotropes.

Dynamic changes in spontaneous intracellular free calcium oscillations and their relationship to prolactin gene expression in single, primary mammotropes.

Cytosolic calcium plays a critical role in the control of a number of genes, including that of the pituitary hormone PRL. Cells that secrete this hormone, termed mammotropes, display spontaneous oscillations of intracellular free calcium ([Ca2+]i) that are positively correlated to PRL release. However, the precise contribution of calcium signaling to the expression of any gene including PRL has remained obscure owing to the requirement for and lack of a strategy for monitoring both of these dynamic variables (gene expression and [Ca2+]i oscillations) in the same living cell. In the present study, we overcame this technical limitation by making real-time measurements of PRL gene expression in transfected, primary rat mammotropes previously subjected to [Ca2+]i determinations by digital imaging fluorescence microscopy of fura-2. Our results showed that the majority of mammotropes (75%) exhibited distinct oscillatory behaviors that could be subgrouped on the basis of frequency/amplitude of [Ca2+]i changes, whereas the remainder (25%) were quiescent (nonoscillatory). Interestingly, most mammotropes displayed spontaneous transitions between oscillatory and quiescent states over the course of several hours. As a consequence of this oscillatory plasticity, there was not a positive correlation between [Ca2+]i dynamics and gene expression at any point in time, as would be predicted by studies with entire populations of cells. Instead, the relationship was distinctly inverse, suggesting that dynamic changes in PRL gene expression may be regulated by temporally dissociated transitions between quiescent and oscillatory states.