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Biomedical subjects

A Levy

Publications and source records attributed to A Levy.

At least 37 records · Page 2Linked to original sources
PubMed2004

Permissive effects of thyroid hormones on rat anterior pituitary mitotic activity.

The anterior pituitary is active mitotically and apoptotically under basal conditions and in response to a variety of physiological and pathophysiological stimuli. Hypothyroidism in man is associated with a modest but very occasionally dramatic increase in overall pituitary size. The mechanisms underlying this reversible phenomenon remain obscure. In the present study we have examined young adult rat anterior pituitary following surgical thyroidectomy and subsequent thyroid hormone treatment and withdrawal using an extremely accurate system for quantifying directly identified mitotic and apoptotic events. Despite the expected increase in the number and/or proportion of immunohistochemically identifiable thyrotrophs three weeks after thyroidectomy, mitotic and apoptotic activity remained unchanged, as did pituitary wet weight, in comparison with sham-operated and intact controls. In contrast, mitotic but not apoptotic activity was enhanced by treatment of thyroidectomized animals with thyroid hormones (triiodothyronine (T3) and thyroxine (T4) 1.8 microg and 3.6 microg/100 g body weight per day respectively), and once again declined to levels seen in intact animals within 72 h of subsequent thyroid hormone withdrawal. Thyroid hormone-induced enhancement of mitotic activity was also seen in intact rats treated with similar doses of thyroid hormones for 7 days and in thyroidectomized rats treated for a similar period with very low dose thyroid hormone replacement at a level that had no effect on raised hypothalamic TRH- or pituitary TSHbeta-transcript prevalence (0.018 microg T3 plus 0.036 microg T4/100 g body weight per day). Thus changes in mitotic and apoptotic activity are unlikely to be the principle mechanism for the apparent increase in thyrotrophs up to 4 weeks after thyroidectomy. In contrast, the data indicate that thyroid hormones have a permissive effect on anterior pituitary mitotic activity in thyroidectomized male rats. Thyroid hormone-induced enhancement of mitotic activity in intact rats further suggests that in euthyroid rats, ambient thyroid hormone levels are a limiting factor for anterior pituitary mitotic activity. In summary, this time course study of young, male rats has shown for the first time that thyroidectomy, thyroid hormone replacement and subsequent withdrawal has no significant effect on anterior pituitary apoptotic activity. Secondly, it has shown that the anterior pituitary mitotic response to thyroidectomy is blocked by complete thyroid hormone deprivation, but can be restored by very low level thyroid hormone replacement, and thirdly that in intact animals thyroid hormone levels significantly limit anterior pituitary mitotic activity.

Animals↗
PubMed2004

Pituitary mitosis and apoptotic responsiveness following adrenalectomy are independent of hypothalamic paraventricular nucleus CRH input.

We have previously identified a series of age-dependent, temporally constrained and closely interdependent mitotic and apoptotic events in the male rat anterior pituitary that occur in response to timed single and repeated hypothalamo-pituitary-adrenal axis stimuli. One of the most dramatic of these is the short burst of apoptosis that occurs 24-48 h after exposure to dexamethasone. If bilateral adrenalectomy precedes exposure to dexamethasone by 1-2 weeks, mitotic activity is transiently increased and the subsequent apoptotic response to dexamethasone greatly enhanced. This study was designed to determine whether adrenalectomy-induced augmentation of the apoptotically sensitive pituitary cell population is mediated via glucocorticoid withdrawal at the level of the pituitary, or whether increased exposure to hypothalamo-hypophyseal trophic hormones of paraventricular origin is responsible. We used stereotaxic surgery to isolate both paraventricular nuclei without disturbing either median eminence input from the arcuate and supraoptic nuclei, or the hypothalamo-hypophyseal-portal blood flow that carries a significant proportion of the pituitary systemic supply. When bilateral adrenalectomy and paraventricular nucleus disconnection were combined, the adrenalectomy-induced increase in anterior pituitary pro-opiomelanocortin (POMC) transcript prevalence was abolished, confirming the loss of paraventricular corticotrophin-releasing hormone (CRH) input. However, the amplitude and pattern of the adrenalectomy-induced anterior pituitary mitotic response and enhancement of the apoptotic response to dexamethasone 1 week later remained completely intact. These data demonstrate that anterior pituitary trophic responses following bilateral adrenalectomy are more likely to be mediated through direct glucocorticoid withdrawal at the level of the pituitary rather than via changes in hypothalamo-hypophyseal releasing factor exposure. This finding highlights the presence of distinct control systems for pituitary hormone gene expression and pituitary mitotic and apoptotic responses.

Adrenalectomy↗
PubMed2004

Improved method for the detection of TATP after explosion.

TATP in post explosion exhibits was reported earlier to be best recovered from vapor phase. A typical procedure includes its adsorption on Amberlite XAD-7, elution with acetonitrile and analysis by GC/MS. In this work, improved recovery of TATP from the vapor phase was achieved by SPME using PDMS/DVB fiber and immediate sampling to GC/MS. The recovery of TATP by SPME was compared with headspace and with adsorption on Amberlite XAD-7 by spiking onto filter paper put in a 100 mL beaker. The limit of detection of TATP was 6.4 ng in these conditions, few orders magnitude more than in the other tested methods. Recovery of TATP in the presence of various solvents was also studied. Acetone, water, and mixtures of water:alcohols (1:1) were found to reduce the recovery of TATP. Using SPME, TATP has been identified in dozens of post-explosion cases.

Acetone↗
PubMed2003

The effect of specific immunotherapy on T-cell receptor repertoire in patients with allergy to house-dust mite.

BACKGROUND: The precise mechanism of specific immunotherapy (SIT), long used for treating allergic diseases, remains undefined. SIT was shown to act by modifying the immune response of T lymphocytes to antigens. We examined the effect of SIT on the expression and use V-alpha, -beta, -gamma and -delta chains of T-cell receptors (TCR) in patients allergic to house-dust mite. METHODS: Peripheral venous blood was taken for lymphocyte TCR analysis from 10 house-dust mite (HDM) allergic adults before initiating SIT and 6 months after initiating the treatment. Twelve similarly allergic patients without SIT served as controls. TCR chains were identified by fluorescence-activated cell sorter (FACS) using the following monoclonal antibodies: CD3, CD14, CD8, pan alpha-beta, pan gamma-delta, V-alpha2, V-alpha12.1, V-beta5a, V-beta5b, V-beta5c, V-beta8a, V-beta8b, V-beta3.1, V-beta13, V-beta12, V-beta6.7, V-delta1, V-delta2, V-gamma9, and V-gamma4. RESULTS: Analyzed before and 6 months after SIT initiation, lymphocyte TCR showed significantly increased V-beta5b, V-beta12 and V-alpha12.1 values compared to controls (without significant changes in other markers). CONCLUSIONS: SIT caused selective expansion of certain V-beta- and V-alpha-expressing T cells in patients allergic to HDM. Our results support the notion that the effect of SIT in patients with allergic rhinitis may be achieved by modifying the T lymphocyte response through the modulation of TCR usage.

Adult↗
PubMed2003

Isolated chemotherapeutic perfusion of the pelvis for advanced rectal cancer.

OBJECTIVE: Isolated pelvic perfusion exposes tissue to high doses of drug without the toxicity of high-dose systemic therapy and may benefit patients with advanced malignancy. PATIENTS AND METHODS: There were 32 patients with locally advanced, previously irradiated cancer of the rectum and 5 patients with anal canal cancer. These patients underwent a total of 65 isolated pelvic perfusions using 5-Fu (1500 mg/m2) for 60 min; cisplatinum (100 mg/m2) and mitomycin (10-20 mg/m2) were added to some perfusions. Hospital stay averaged 3-5 days. RESULTS: Palliative perfusion in 15 patients with advanced rectal cancer resulted in symptomatic relief from 1 to 4 months in 11 of 14 with pelvic pain and limited benefit in 6 patients with mass, but no pain. Pre-operative perfusion in 16 rectal cancer patients achieved a complete response (no tumour in pelvis) in 1 patient and significant tumour regression in 8 patients rendering them potentially resectable. Five were resected with clear margins. Three patients with recurrent epidermoid cancer had significant tumour regression and were resected with clear margins. CONCLUSION: Isolated chemotherapeutic perfusion of the pelvis provides excellent palliation for patients with advanced or pelvic recurrence of rectal cancer or epidermoid cancer of anorectum and may potentiate resection in selected patients.

Adult↗
PubMed2003

New candidate virus in association with Hodgkin's disease.

Epidemiologic and molecular investigations of Hodgkin's disease (HD) suggest a strong infectious association. The Epstein-Barr virus (EBV), together with its viral proteins, is expressed in Hodgkin-Reed-Sternberg (HRS) cells in the lymph nodes involved by HD. EBV is more likely to be related to childhood and older adult cases of HD and is much less frequently expressed in young adult HD patients, the group most expected to be associated with an infectious agent. In addition, the "hit and run" theory of EBV infection remains speculative and no other lymphotropic viruses studied to date seem to satisfy the quest for a new candidate virus in young adults with HD. We have recently found preliminary evidence suggesting a possible association between the measles virus (MV) and HD. This evidence is the subject of the present review.

Adolescent↗
PubMed2003

Photography in dermatology: comparison between slides and digital imaging.

BACKGROUND: Clinical photography is an essential tool for any medical speciality, such as dermatology, wherein accurate records are required of pre, intra and postoperative findings, plus quick access to these records for comparison and evaluation purposes. Clinical photography is important not only to the surgeon, but also to the patient, so that a realistic objective assessment of improvement may be made. Conventional emulsion film-based prints from negatives and positive colour transparencies revolutionised clinical records when they first appeared. Now the appearance and rapid development of digital photography is bringing about yet another revolution. AIM: To compare conventional with digital photography from the standpoints of cost-effectiveness, ease of archiving and ease of retrieval. The quality of the imaging was not dealt with. METHODS: A professional clinical photographer took images using: Nikon F3 (conventional emulsion based photography); FotoFinder Derma (digital photography). RESULTS: Although traditional emulsion-based photographs are quicker to take, digital imaging provides an almost immediately available image and is much swifter to use for classification, later retrieval and comparison between serial images. CONCLUSIONS: Despite the initial expense of acquiring digital equipment compared with traditional photographic apparatus, when examined over a five-year period, both formats cost approximately the same. Digital photography offers advantages in ease of archiving and storage, savings in time and space, extremely quick retrieval and very easy comparison of images. Digital photography is very much the way of the future in dermatological clinical imaging.

Journal Article↗
PubMed2003

Temporally sensitive trophic responsiveness of the adrenalectomized rat anterior pituitary to dexamethasone challenge: relationship between mitotic activity and apoptotic sensitivity.

Depending on timing and dose, exogenous glucocorticoids induce a wave of apoptosis in the adult rat anterior pituitary, a response that is enhanced by adrenalectomy. In this study, we show that the size of the glucocorticoid-sensitive apoptotic population progressively increases during the week following surgical adrenalectomy, plateaus for a further week, then spontaneously declines to levels seen in intact animals by 4 wk. Mitotic activity, in contrast, rises rapidly post adrenalectomy but returns to baseline within 2 wk. Increased mitotic activity precedes the increase in the population of cells that undergo glucocorticoid-induced apoptosis and the subsequent decline in mitotic activity precedes the decline in apoptotic sensitivity despite persistent elevation of hypothalamic CRH and pituitary proopiomelanocortin transcripts. If glucocorticoid exposure is delayed until 4 wk post adrenalectomy when the apoptotic response has returned to baseline, glucocorticoid withdrawal, by transiently increasing mitotic activity, again primes the formation of an expanded glucocorticoid-sensitive apoptotic cell population. These data suggest that apoptotic sensitivity is largely confined to cells that have recently entered the cell cycle. This observation is further corroborated by demonstrating an abrupt glucocorticoid-induced step-down in the bromodeoxyuridine-labeling index to basal levels in rats given daily injections of bromodeoxyuridine during the week following adrenalectomy.

Adrenalectomy↗
PubMed2003

Enhanced anterior pituitary mitotic response to adrenalectomy after multiple glucocorticoid exposures.

OBJECTIVES: Glucocorticoid withdrawal in man is associated with transient but sometimes prolonged impairment of hypothalamo-pituitary-adrenal axis secretory responsiveness. This has led to continued concern in the clinical arena. The acute anterior pituitary response to glucocorticoids in the rat includes apoptosis-mediated deletion of a cell population. Whilst continued cell turnover following glucocorticoid withdrawal and the potential for differentiation of uncommitted precursor cells and transdifferentiation of other secretory cell types predicts that, given sufficient time, complete anterior pituitary trophic recovery is likely, this hypothesis has not previously been tested. DESIGN AND METHODS: We have quantified pituitary mitotic and apoptotic rate, as well as corticotroph number and pro-opiomelanocortin transcript prevalence, together with hypothalamic corticotrophin-releasing hormone and vasopressin transcript prevalence 5 weeks after three short dexamethasone treatments each separated by a week. Bilateral adrenalectomy was then carried out as a maximal secretory and trophic stimulus, and the response to a fourth dexamethasone treatment assessed 1 week later. RESULTS: Anterior pituitary mitotic index was significantly higher in rats previously exposed to dexamethasone compared with age-matched controls exposed to dexamethasone for the first time. No differences were found in the subsequent apoptotic response to a fourth dexamethasone treatment or in the levels of paraventricular corticotrophin-releasing hormone or vasopressin transcripts or pituitary pro-opiomelanocortin transcripts. CONCLUSIONS: These data indicate that full recovery of pituitary mitotic activity takes longer than the recovery of secretory parameters, and suggest that, for several weeks after glucocorticoid exposure, the ability of the pituitary to meet fresh demands placed on it may be suboptimal.

Adrenalectomy↗
PubMed2003

[Causes of uncontrolled hypertension. DUO-HTA survey].

OBJECTIVES: To identify the socio-demographic, clinical, psycho-behavioural and therapeutic factors explaining uncontrolled blood pressure in a population of hypertensives in ambulatory practice. METHODS: The DUO-HTA survey is a national, cross-sectional, mirrored, observational study, from a representative sample of 347 general practitioners (MG) and 210 cardiologists, and a population of 2022 hypertensive patients followed by these doctors. The data were collected by means of questionnaires completed by the hypertensives and their doctors. RESULTS: The factors significantly discriminating patients for whom BP was controlled (C) from those patients whose BP was not controlled (NC) were an age less than 65 years, smoking, obesity, alcohol consumption, sedentary lifestyle and multiple anti-hypertensive treatment. On the psycho-behavioural front, the NC patients were more often anxious and irritable, claiming to lead a stressful life and for whom hypertension was often perceived as a "foreign entity" and a source of frustration and multiple deprivations. The factors discriminating the NC doctors from the C doctors were essentially psycho-behavioural, with the NC doctors considering the management of hypertension as being less gratifying, and hypertension as a condition with fluctuating progression, poorly understood and dramatized by patients. CONCLUSION: The DUO-HTA survey underlines the weight of reciprocal representation systems in hypertension for patients and their doctors, as well as the quality of the doctor-patient relationship in blood pressure control. It prompts the development of sensitisation actions for practitioners centered on improving the doctor-patient relationship.

Adult↗
PubMed2002

Nasal midazolam as a novel anticonvulsive treatment against organophosphate-induced seizure activity in the guinea pig.

Seizures and status epilepticus, which may contribute to brain injury, are common consequences of exposure to organophosphorus (OP) cholinesterase inhibitors. Effective management of these seizures is critical. To investigate the efficacy of nasal midazolam as an anticonvulsive treatment for OP exposure, as compared to intramuscular midazolam, guinea pigs were connected to a recording swivel for electrocorticograph (ECoG) monitoring and clinical observation. The experimental paradigm consisted of pyridostigmine pretreatment (0.1 mg/kg i.m.) 20 min prior to sarin exposure (1.2x LD(50,) 56 micro g/kg i.m.). One minute post-exposure, atropine (3 mg/kg i.m.) and TMB-4 (1 mg/kg im) were administered. Within 3-8 min after sarin exposure all animals developed electrographic seizure activity (EGSA), with convulsive behavior. Treatment with midazolam (1 mg/kg i.m.) 10 min after the onset of EGSA abolished EGSA within 389+/-181 s. The same dose was not effective, in most cases, when given 30 min after onset. However, a higher dose (2 mg/kg) was found efficacious after 30 min (949+/-466 s). In contrast, nasal application of midazolam (1 mg/kg) was found most effective, with significant advantages, in amelioration of EGSA and convulsive behavior, when given 10 min (216+/-185 s) or 30 min (308+/-122 s) following the onset of EGSA ( P<0.001). Thus, nasal midazolam could be used as a novel, rapid and convenient route of application against seizure activity induced by nerve agent poisoning.

Administration, Intranasal↗
PubMed2002

Risk factors for arrest of descent during the second stage of labor.

OBJECTIVE: To define obstetrical risk factors for arrest of descent during the second stage of labor and to determine perinatal outcome. STUDY DESIGN: All singleton, vertex, term deliveries with an unscarred uterus, between the years 1988 and 1999 were included. Univariable and multivariable analysis were performed to investigate independent risk factors associated with arrest of descent during the second stage of labor and the perinatal outcome. RESULTS: The study included 93266 deliveries, of these 1545 (1.7%) were complicated with arrest of descent during the second stage of labor. Using a multivariable analysis, the following obstetric risk factors were found to be significantly associated with arrest of descent: nulliparity (OR=7.8, 95% CI=6.9-8.7; P<0.001), birth weight >4 kg (OR=2.3, 95% CI=1.9-2.8; P<0.001), epidural analgesia (OR=1.8, 95% CI=1.6-2.0; P<0.001), hydramnios (OR=1.6, 95% CI=1.3-2.0; P<0.001), hypertensive disorders (OR=1.5, 95% CI=1.3-1.8; P<0.001), gestational diabetes A1 and A2 (OR=1.5, 95% CI=1.2-1.8; P<0.001), male gender (OR=1.4, 95% CI=1.2-1.5; P<0.001), premature rupture of membranes (PROM, OR=1.3, 95% CI=1.04-1.6; P=0.021), and induction of labor (OR=1.2, 95% CI=1.02-1.4; P=0.030). Deliveries complicated by arrest of descent resulted in cesarean section in 20.6%, vacuum extraction in 74.0%, and forceps delivery in 5.4%. Newborns delivered after arrest of descent during the second stage of labor had significantly higher rates of low Apgar scores (<7) at 1 and 5 min, as compared to the controls (12.7 vs. 2.1%, P<0.001; and 0.9 vs. 0.2%, P<0.001, respectively). Nevertheless, no significant differences were noted between the groups regarding perinatal mortality (0.38 vs. 0.44%; P=0.759). CONCLUSIONS: Major risk factors for arrest of descent during the second stage of labor were nulliparity, fetal macrosomia, epidural analgesia, hydramnios, hypertensive disorders and gestational diabetes mellitus. These risk factors should be carefully evaluated during pregnancy in order to actively manage high-risk pregnancies.

Analgesia, Epidural↗
PubMed2002

Conversion motor paralysis disorder: analysis of 34 consecutive referrals.

STUDY DESIGN: We present our cumulative experience with patients sustaining the most dramatic type of Conversion Disorder (CD) - Conversion Motor Paralysis. SETTING: Rehabilitation departments, Reuth Medical Center, Tel-Aviv and Sheba Medical Center, Tel-Hashomer, Israel. METHODS: During the period 1973-2000, 34 patients with neurological symptoms without any anatomical or physiological basis were admitted to both rehabilitation departments. This number consists of less than 1% of the total acute traumatic and non-traumatic spinal cord disorders admitted annually to these centers. RESULTS: Twenty-five of the subjects were men (mean age of 30 years) and nine were women (mean age of 31.4 years). Neurological symptoms included: paraplegia (complete or incomplete) (18), hemiplegia or hemi paresis (11), tetraplegia (complete or incomplete) (three), monoplegia (one), triplegia (one). The final diagnosis on discharge was CD in 30 of the 34 cases, the remaining four being diagnosed as malingering. Functionally, nine patients had a complete recovery, 10 a partial recovery and 15 remained unchanged. CONCLUSION: Disabled people who experienced traumatic events resulting in various disabilities are admitted usually to a rehabilitation center. However, some of them are later diagnosed as having Conversion Disorder or malingering. We believe that their participation in active regular and integrative rehabilitation process is beneficial to most of them. Most of these patients gain functional independence and return to the main stream of life.

Adult↗
PubMed2002

Conversion motor paralysis disorder: overview and rehabilitation model.

It is important to consider a differential diagnosis between paralysis on an organic basis and paralysis and disability due to psychological mechanisms in people with physical impairment secondary to trauma, without evidence of organic etiology. We review the most dramatic type of conversion disorder (CD)-'Conversion Motor Paralysis'. Recent important medical literature concerning the accepted treatment and rehabilitation management will be reviewed and discussed. The inter-disciplinary in-patient team management approach in a rehabilitation setting offers the benefits of a comprehensive assessment and treatment. The diagnosis is temporary and conditional, since there may be a long delay until the appearance of organic findings. A complete medical assessment is essential in order to rule out any possibility of an organic etiology. In as many as 25% to 50% of patients diagnosed as conversion, an organic medical diagnosis was found.

Behavior Therapy↗
PubMed2002

Cerebral venous sinus thrombosis in a neonate due to factor V Leiden deficiency.

UNLABELLED: A case is described of cerebral venous sinus thrombosis due to factor V Leiden deficiency that occurred in the neonatal period, presenting with seizures. Diagnosis was based on ultrasonography, Doppler ultrasound (US) and magnetic resonance imaging (MRI). The aetiology was only recognized after blood-clotting tests, antithrombin III, C and S protein levels and factor V Leiden were studied. This situation was treated with intravenous heparin controlled by activated partial thromboplastin time (APTT). MRI angiography and Doppler US were important in the follow-up. It is important to assess periodically the neurological development of the baby and to prevent situations such as dehydration or severe infection, which can precipitate further thrombotic events. Molecular genetics allowed the identification of this trait in other family members. CONCLUSION: In every newborn with a thrombotic episode, coagulation studies must be performed, including testing for activated protein C (APC) resistance. Doppler US flow measurement and the MRI studies provide the best tools for diagnosis and follow-up. Heparin should be given to double the initial individual APTT. It is important to prevent any risk situation such as dehydration or severe infection, which could lead to a recurrence of a thrombotic episode. Regular assessment of the child's neurodevelopment is an important aspect of further care.

Activated Protein C Resistance↗
PubMed2002

Obstetric risk factors for failure to progress in the first versus the second stage of labor.

OBJECTIVE: To compare obstetric risk factors for failure of labor to progress in the first versus the second stage. STUDY DESIGN: A comparison was performed of all singleton, vertex and term deliveries with an unscarred uterus, complicated with non-progressive labor during the first and the second stages. Deliveries occurred between the years 1988 and 1999 in a tertiary university medical center. RESULTS: Patients with non-progressive labor in the first stage (n = 1197) were significantly older, of higher birth order, and were more likely to have complications such as gestational diabetes, hypertensive disorders, premature rupture of membranes, meconium-stained amniotic fluid, hydramnios and oligohydramnios (p < 0.001 for all variables) as compared to patients with non-progressive labor in the second stage (n = 1545). In addition, pregnancies complicated with non-progressive labor in the first stage had a significantly higher rate of fetal macrosomia as compared to patients with non-progressive labor in the second stage (11.6% vs. 8.8%; p < 0.001). CONCLUSIONS: Higher rates of fetal macrosomia and high-risk pregnancies were noted among pregnancies complicated with non-progressive labor during the first vs. the second stage. The significant increase in Cesarean deliveries during the first stage of labor among high-risk pregnancies might reflect exaggerated concern of caregivers. This concern may influence an overall conservative attitude leading to the seemingly simpler mode of direct intervention by Cesarean delivery.

Adolescent↗
PubMed2002

Physiological implications of pituitary trophic activity.

A complete inventory of pituitary trophic responses depends on precise estimates of mitotic activity and apoptotic events, and accurate characterization and quantification of pituitary cell subtypes irrespective of previous and current physiological demand. For a discrete structure that has been so extensively studied, it is disappointing but perhaps not surprising that none of these measures is available and therefore that the relative contributions to changes in the proportions of pituitary cellular subpopulations of trophic activity, differentiation of pluripotent cells and variations in the secretory profiles of apparently committed cells remain almost impossible to determine. To fully appreciate the extent of this dilemma, it should be remembered that conservative estimates of the proportion of corticotrophs in the rat anterior pituitary under basal conditions vary over twofold and that it is still not clear whether the apparent threefold increase in mammotrophs during pregnancy is the result of maturation of uncommitted cells, transdifferentiation of other cells such as somatotrophs, cell division, or a mixture of all three. Equally, while it has been known for some time that adrenalectomy results in a transient increase in anterior pituitary mitotic activity and appropriately timed supraphysiological glucocorticoid replacement with a wave of apoptosis, the precise identity of the cells involved in both of these responses is open to question. Thus, although many of the physiological stimuli associated with apparent changes in the proportions of pituitary cellular subpopulations are known, the precise mechanism of the changes and the consequences of the same remain obscure. This review summarizes the limited literature on pituitary trophic activity and asks what, if anything, analysis of pituitary trophic activity using current technology can tell us.

Adrenal Glands↗