Search PubMed⌕ Search

Biomedical subjects

E Gould

Publications and source records attributed to E Gould.

At least 55 records · Page 3Linked to original sources
PubMed1995

Regulation of adult neurogenesis by excitatory input and NMDA receptor activation in the dentate gyrus.

The effects of afferent input and N-methyl-D-aspartate (NMDA) receptor activation on neurogenesis were examined in an intact system, the rat dentate gyrus, where neurons are naturally born in the adult. In the adult dentate gyrus, activation of NMDA receptors rapidly decreased the number of cells synthesizing DNA, whereas blockade of NMDA receptors rapidly increased the number of cells in the S phase identified with 3H-thymidine. Acute treatment with NMDA receptor antagonists increased the birth of neurons and increased the overall density of neurons in the granule cell layer. Lesion of the entorhinal cortex, the main excitatory afferent population to the granule neurons, also increased the birth of cells in the dentate gyrus. These results suggest that adult neurogenesis in the dentate gyrus of the rat is altered by afferent input, via NMDA receptors, and may be regulated naturally by endogenous excitatory amino acids.

2-Amino-5-phosphonovalerate↗
PubMed1994

The effects of adrenal steroids and excitatory input on neuronal birth and survival.

The dentate gyrus of the rat forms in three developmental phases, each of which is characterized by neuronal birth, migration and death. Recent evidence indicates that adrenal steroids regulate neuronal birth, death, and possibly migration throughout the life of the animal. However, the observation that very few neuroblasts in the developing or adult dentate gyrus express adrenal steroid receptors suggests that the effects of adrenal steroid manipulations on neurogenesis are indirect. Additional evidence indicates that NMDA receptor activation regulates neuronal birth and death in this brain region presenting the possibility that adrenal steroids influence these processes through direct actions on excitatory afferents. Future studies will address this possibility.

Adrenal Cortex Hormones↗
PubMed1994

Effects of adrenalectomy on spatial memory performance and dentate gyrus morphology.

Adrenalectomy (ADX) causes neuronal degeneration and cell loss in the dentate gyrus (DG) of the hippocampus. Since chemical or mechanical lesions of the DG are associated with impairments of spatial memory in rats, the effects of ADX on radial arm maze performance were evaluated. During 15 trials, where all 8 arms of the maze were baited, ADX rats were significantly impaired compared to sham operated controls (Shams). These trials were conducted 21-42 days post-ADX. Following these trials, time delays were instituted between the 4th and 5th choices, and ADX rats continued to show impaired performance. Daily intake of 3% saline was monitored in all rats and serum corticosterone (Cort) was measured. Saline consumption (ml/day) was higher in the ADX group (16.9 +/- 1.6 in ADX vs. 1.3 +/- 0.3 in Shams) and was negatively correlated with Cort level. Serum Cort (% microgram) differed between groups (0.6 +/- 0.4 vs. 15.0 +/- 2.3) and was negatively correlated with a greater number of maze errors, a measure of impaired performance. Cross sectional DG area was not reduced in ADX rats, and pyknotic cell number did not differ significantly between ADX and Sham animals. Moreover, pyknotic cell counts did not correlate with behavioral measures. These results lead to two conclusions: First, the recovery of accessory adrenal tissue in ADX rats, as indicated by the low levels of Cort, appears sufficient to suppress dentate granule neuron pyknosis, but may not be sufficient to suppress salt appetite.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1994

Blockade of NMDA receptors increases cell death and birth in the developing rat dentate gyrus.

Excitatory input regulates cell birth and survival in many systems. The granule cell population of the rat dentate gyrus is formed primarily during the postnatal period. Excitatory afferents enter the dentate gyrus and begin to form synapses with granule cells during the first postnatal week, the time of maximal cell birth and death. In order to determine whether excitatory input plays a role in the regulation of cell birth and survival in the developing granule cell layers and their germinal regions, the subependymal layer and hilus, we treated rat pups with the N-methyl D-aspartate (NMDA) receptor antagonists MK-801, CGP 37849, or CGP 43487 during the first postnatal week and examined the numbers of 3H-thymidine-labeled cells, pyknotic cells, and healthy cells in these regions. In order to determine the cell type that was affected, sections from brains of MK-801-treated rats were processed for 3H-thymidine autoradiography combined with immunohistochemistry for the marker of radial glia, vimentin, and the marker of mature astrocytes, glial fibrillary acidic protein (GFAP). Within the dentate gyrus, NMDA receptor blockade resulted in the following changes: (1) the density of 3H-thymidine-labeled cells was increased, (2) the density of pyknotic cells was increased, (3) the density of 3H-thymidine-labeled pyknotic cells was increased, and (4) the density of healthy cells was decreased. The infrapyramidal blade/hilus showed changes throughout its extent, whereas the suprapyramidal blade showed changes only at the rostral level. No change in the numbers of 3H-thymidine-labeled vimentin-immunoreactive or GFAP-immunoreactive cells was observed in the dentate gyrus with MK-801 treatment, indicating that glia are not primarily affected by NMDA receptor blockade. Blockade of NMDA receptors resulted in gross morphologic changes in the dentate gyrus; in most cases, the infrapyramidal blade was indistinguishable from the hilus. Moreover, in several brains of animals treated with CGP 37849 or CGP 43487 on postnatal day (P)5, an abnormal aggregation of cells was observed ventral to the normal location of the infrapyramidal blade. This cellular cluster contained many pyknotic and 3H-thymidine-labeled cells and may represent cells that normally comprise the infrapyramidal blade. Dramatic changes to the subependymal layer were also seen following NMDA receptor blockade. The cross-sectional area of this region was significantly increased with MK-801, CGP 37849, or CGP 43487 treatment and contained a high density of 3H-thymidine-labeled cells and 3H-thymidine-labeled pyknotic cells.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1994

Adult neurogenesis is regulated by adrenal steroids in the dentate gyrus.

The dentate gyrus of the rat produces new granule neurons well into adulthood. In the adult, newly born granule neurons migrate from the hilus to the granule cell layer, receive synaptic input, extend axons into the mossy fiber pathway, and express a neuronal marker. No previous studies have identified factors that regulate neuronal birth in the adult dentate gyrus. In order to determine whether glucocorticoids control neurogenesis in the adult dentate gyrus, the effects of adrenal steroid manipulations on neuronal birth were assessed using [3H]thymidine autoradiography and immunohistochemistry for the neuronal marker neuron specific enolase. Acute treatment with corticosterone produced a significant decrease in the density of [3H]thymidine-labeled cells in the hilus of the dentate gyrus. In contrast, removal of endogenous adrenal steroids stimulated increased neuronal birth; adrenalectomy resulted in a significant increase in the number of neuron specific enolase-immunoreactive [3H]thymidine labeled cells in the granule cell layer compared to sham operation. Replacement of corticosterone to adrenalectomized rats after [3H]thymidine injection did not substantially alter the increase in neurogenesis observed following adrenalectomy, even though this replacement protects cells from adrenalectomy-induced cell death. These results indicate that the rate of neurogenesis in the dentate gyrus of the adult rat is dependent upon the levels of circulating adrenal steroids.

Adrenalectomy↗
PubMed1993

Adrenal steroid receptor immunoreactivity in cells born in the adult rat dentate gyrus.

Several lines of evidence indicate that cell birth in the adult rat dentate gyrus is regulated by adrenal steroids. The expression of adrenal steroid receptors by mitotic cells in the dentate gyrus would support the hypothesis that these hormones act directly on granule cell progenitors. We performed a survival time course of in vivo [3H]thymidine autoradiography combined with immunohistochemistry for mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) and found that very few [3H]thymidine labeled mitotic cells express these receptors. By 4 weeks following [3H]thymidine administration, the vast majority of [3H]thymidine labeled cells were immunoreactive for MR and GR. These results suggest that adrenal steroids do not act directly on granule cell progenitors in the adult rat dentate gyrus.

Animals↗
PubMed1993

Differentiation of newly born neurons and glia in the dentate gyrus of the adult rat.

In order to determine whether newly born cells in the dentate gyrus of the adult rat express the neuronal marker, neuron-specific enolase, or the glial marker, glial fibrillary acidic protein, we performed combined immunohistochemistry and autoradiography on brains from adult rats perfused at various times ranging from 1 h to four weeks following [3H]thymidine administration. Light-microscopic examination revealed a negligible number of [3H]thymidine-labeled cells showing neuron-specific enolase immunoreactivity during mitosis. However, by two weeks after [3H]thymidine administration, a significant increase in the density of [3H]thymidine-labeled neuron-specific enolase-immunoreactive cells was detected. Three weeks following [3H]thymidine injection the majority of [3H]thymidine-labeled cells (> 70%) were immunoreactive for the neuronal marker. At the four-week time-point, [3H]thymidine-labeled neuron-specific enolase-immunoreactive cells were indistinguishable from neighboring granule cells. In contrast, glial fibrillary acidic protein immunoreactivity was observed in a small but significant number of [3H]thymidine cells at the 1-h time-point and the proportion of labeled cells that were immunoreactive for this cell marker did not increase with time. [3H]Thymidine-labeled cells that were immunoreactive for glial fibrillary acidic protein typically showed morphologic characteristics of radial glia at all time-points. At the 1-h time-point, the majority of [3H]thymidine-labeled cells were observed in the hilus (> 60%) with the remainder being located in the granule cell layer. However, with a four-week survival-time most [3H]thymidine-labeled cells (> 85%) were located in the granule cell layer. The majority of newly born cells in the adult dentate gyrus differentiate into neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Neuronal birth and death.

Neurogenesis and cell death occur predominantly during the postnatal period in the dentate gyrus of the rat. Recent studies have shown that mitosis and apoptosis in this system are regulated by adrenal steroids, possibly through excitatory amino acids. Studies performed in other systems have identified genes that mediate cell birth and death, which may also participate in the development and maintenance of the dentate gyrus.

Adrenal Glands↗
PubMed1993

Mucinous breast carcinoma. Single cutaneous metastasis.

BACKGROUND: Mucinous or colloid carcinoma is an uncommon breast neoplasm which is generally associated with a good prognosis. Metastases tend to occur late in the disease and are found principally in lymph nodes, lungs, and bones. The longest latency period reported for development of a distant metastasis is 30 years after primary resection of the tumor. OBJECTIVE: To describe a case of cutaneous metastasis from a mucinous breast carcinoma occurring 22 years after initial resection and review the literature. RESULTS: Comparison of the primary tumor with the metastatic lesion showed identical histology. Review of the literature revealed this case represents the second longest latency for a distant metastasis from mucinous breast carcinoma and the unusual involvement of the skin. CONCLUSION: This represents the second longest reported latency period for the development of a distant metastasis from mucinous breast carcinoma and its rare occurrence in the skin.

Adenocarcinoma, Mucinous↗
PubMed1993

Treatment by a psychotherapist and a psychopharmacologist: transference and countertransference issues.

Recent surveys suggest that collaborations between psychiatrists acting as medication consultants and therapists providing psychotherapy are an increasingly common form of treatment. Complex transference and countertransference reactions can arise in these "therapeutic triangles." Risks include splitting by the patient, conflicts between the two practitioners, and premature termination of either the psychotherapy or pharmacotherapy. The authors discuss typical transference and countertransference reactions that can lead to these problems and present case examples of productive and unproductive collaborative efforts. The authors describe a collaborative approach based on mutual respect, trust, and openness that, along with an awareness of typical transference and countertransference issues, can increase the likelihood of a positive treatment outcome.

Adult↗
PubMed1993

The accuracy of the histological classification of lung carcinoma and its reproducibility: a study of 75 archival cases of adenosquamous carcinoma.

The classification of lung carcinoma into a small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC), is highly reproducible. There are few studies on the reproducibility of subtyping NSCLC, with anecdotal reports on the subtype of adenosquamous carcinoma. We undertook a study of 75 cases archived as adenosquamous carcinoma. All cases were accepted as NSCLC on independent review by three pathologists utilizing the 1982 World Health Organization (WHO) classification criteria. The acceptance rate of adenosquamous carcinoma by the three pathologists was 65%, 28%, and 65%. Cases not accepted as adenosquamous fell into the different subtypes of NSCLC, with a concordance rate between each pair of pathologists of 49%, 61% and 43%, indicating poor agreement between pathologists. The study confirms the high reproducibility of the classification into SCLC and NSCLC; it shows poor concordance for all subtypes of NSCLC with poor reproducibility of diagnosis of adenosquamous carcinoma as specified by the 1982 WHO classification. Physicians dealing with lung carcinoma should be aware of this limitation of classification.

Carcinoma, Adenosquamous↗
PubMed1992

Tianeptine attenuates stress-induced morphological changes in the hippocampus.

Repeated 6-h daily restraint stress over 21 days reduces length and number of branch points of hippocampal CA3c pyramidal dendrites in the hippocampal formation of adult male rats. This effect is mimicked by daily injections of 40 mg/kg corticosterone. Daily treatment with tianeptine (15 mg/kg) prior to stress sessions or the corticosterone treatment prevented these effects of stress or corticosterone, respectively. Tianeptine treatment did not prevent the effects of stress to increase adrenal/body weight ratio, nor did it prevent the effects of stress to decrease body weight gain, indicating that its actions are not mediated solely by effects on stress-induced secretion of corticosterone. Because tianeptine is known to enhance neural uptake of serotonin, these results suggest that the serotonergic system may be involved in modulating stress and corticosterone effects on dendritic morphology.

Animals↗
PubMed1992

Stress induces atrophy of apical dendrites of hippocampal CA3 pyramidal neurons.

The hippocampus is vulnerable to the damaging actions of insults such as transient ischemia and repetitive stimulation, as well as repeated exposure to exogenous glucocorticoids. This study investigated effects of a repeated psychological stressor, restraint, on the CA3 pyramidal neurons which are vulnerable to damage by repetitive stimulation. Repeated daily restraint stress for 21 days caused apical dendrites of CA3 pyramidal neurons to atrophy, while basal CA3 dendrites did not change. Rats undergoing this treatment were healthy and showed some adaptation of the glucocorticoid stress response over 21 days; however, stress reduced body weight gain by 14% and increased adrenal weight relative to body weight by 20%. Results are discussed in relation to the possible role of adrenal steroids and excitatory amino acids.

Animals↗
PubMed1992

Merkel cell carcinoma of the eyelid and periocular tissues.

Five patients had eyelid and periocular Merkel cell carcinoma. The tumor was located on the left lower eyelid in two patients, the left upper eyelid in one patient, the right upper eyelid in one patient, and was metastatic to the right outer canthus in one patient. The mean duration of symptoms was approximately four months. The diagnosis of Merkel cell carcinoma was not suspected clinically in any of the four primary eyelid cases, but was only established on histopathologic examination of biopsy specimens. Light microscopy disclosed carcinoma with small primitive cells in all five tumor biopsy specimens. Immunohistochemical studies showed neuron-specific enolase and keratin and transmission electron microscopy demonstrated neurosecretory granules typical for Merkel cell carcinoma. All five patients in this study were treated with wide surgical excision of the eyelid tumors with intraoperative frozen-section monitoring of the margins of resection. The left lower eyelid Merkel cell carcinoma spread to the preauricular lymph node in one patient. This patient subsequently died of metastatic Merkel cell carcinoma. One patient with metastatic right outer canthus Merkel cell carcinoma received radiotherapy (6,550 cGy). Eyelid Merkel cell carcinoma has the potential for recurrence and metastatic spread. We recommend lifetime follow-up for patients treated for eyelid Merkel cell carcinoma.

Aged↗