Dihydroartemisinin-induced ferroptosis in acute myeloid leukemia: links to iron metabolism and metallothionein

Artemisinin is an anti-malarial drug that has shown anticancer properties. Recently, ferroptosis was reported to be induced by dihydroartemisinin (DHA) and linked to iron increase. In the current study, we determined the effect of DHA in leukemic cell lines on ferroptosis induction and iron metabolism and the cytoprotective effect triggered in leukemic cells. We found that treatment of DHA induces early ferroptosis by promoting ferritinophagy and subsequent iron increase. Furthermore, our study demonstrated that DHA activated zinc metabolism signaling, especially the upregulation of metallothionein (MT). Supportingly, we showed that inhibition MT2A and MT1M isoforms enhanced DHA-induced ferroptosis. Finally, we demonstrated that DHA-induced ferroptosis alters glutathione pool, which is highly dependent on MTs-driven antioxidant response. Taken together, our study indicated that DHA activates ferritinophagy and subsequent ferroptosis in AML and that MTs are involved in glutathione regenerating and antioxidant response.

Re-evaluating expanding intravenous catheters in medical practice

BACKGROUND

Intravenous catheters are common and essential devices within medical practice. Their placement can be difficult, leading to application of several technologies to improve success. Functionally expanding catheters were once an exciting technology, derailed clinically by hypersensitivity reactions. The exact cause of reactions, attributed to Aquavene catheter materials, remains unknown.

AIMS

To reinvestigate functionally expanding intravenous catheters.

MATERIALS AND METHODS

The history of the functionally expanding intravenous catheter is presented here along with its utility in current medical practice, potential for further investigation, and possible redesign of these once promising devices.

RESULTS

This review demonstrates clinical utility and a lack of definitive cause for failure of the previous functionally expanding intravenous catheter design. As Aquavene materials themselves are commonly considered the cause of hypersensitivity reactions which removed expanding intravenous catheters from the market, this review found several possible substitutes for this material for use in any redesign.

DISCUSSION AND CONCLUSION

The functionally expanding intravenous catheter failed due to hypersensitivity reactions in patients. Alternative materials exist for a possible redesign on this once promising clinical product.

Swellable catheters based on a dynamic expanding inner diameter

Intravenous (IV) fluid administration is critical for all patients undergoing care in a hospital setting. In-patient hospital practice, surgeries, and emergency care require functional IVs for fluid replacement and medication administration. Proper placement of IVs is vital to providing medical services. The ease of placement of an IV catheter, however, depends not only on the size of the catheter but also on provider experience and patient demographics such as age, body mass index, hydration status, and medical comorbidities present challenges to successful IV placement. Smaller diameter IV placement can improve success and there are instances where multiple small diameter catheters are placed for patient care when larger bore access is unattainable. Smaller inner-diameter catheters for anesthesia have functional constraints. Ideally, there would be a smaller catheter for placement that could function as a larger catheter for patient care. One solution is the idea of functionally responsive catheters. Here, we evaluated tubular-shaped hydrogels as potential functional catheters that can increase in inner diameter through fluid swelling using cross-linked homopolymers of polyacrylamide, PAM (10-40% w/w), and their copolymers with 0-8% w/w Poly-(Ethylene Glycol)-Diacrylate, PEGDA. For the PAM gels, the water transport mechanism was shown to be concentration-dependent Fickian diffusion, with the less concentrated gels exhibiting increasingly anomalous modes. Increasing the PEGDA content in the network yielded an initial high rate of water uptake, characterized by Case II transport. The swelling kinetics depended strongly on the sample geometry and boundary conditions. Initially, in a submerged swelling, the annulus expands symmetrically in both outward and inward directions (it thickens), reducing the internal diameter by up to 70%. After 1 h, however, the inner diameter increases steadily so that at equilibrium, there is a net (>100%) increase in all the dimensions of the tube. The amount of linear swelling at equilibrium depended only on the polymer volume fraction as made, while the rate of inner diameter expansion depended on the hydrophilicity of the matrix and the kinetics of sorption. This study serves as proof of concept to identify key parameters for the successful design of hydrogel-based catheter devices with expanding inner-diameters for applications in medical care.

Use of a fibrin-based system for enhancing angiogenesis and modulating inflammation in the treatment of hyperglycemic wounds

The complex pathophysiology of chronic ulceration in diabetic patients is poorly understood; diabetes-related lower limb amputation is a major health issue, which has limited effective treatment regimes in the clinic. This study attempted to understand the complex pathology of hyperglycemic wound healing by showing profound changes in gene expression profiles in wounded human keratinocytes in hyperglycemic conditions compared to normal glucose conditions. In the hyper-secretory wound microenvironment of hyperglycemia, Rab18, a secretory control molecule, was found to be significantly downregulated. Using a biomaterial platform for dual therapy targeting the two distinct pathways, this study aimed to resolve the major dysregulated pathways in hyperglycemic wound healing. To complement Rab18, and promote angiogenesis eNOS was also targeted, and this novel Rab18-eNOS therapy via a dynamically controlled 'fibrin-in-fibrin' delivery system, demonstrated enhanced wound closure, by increasing functional angiogenesis and reducing inflammation, in an alloxan-induced hyperglycemic preclinical ear ulcer model of compromised wound healing.

Plasma protein denaturation with graded heat exposure

During cardiopulmonary bypass (CPB), perfusion at tepid temperatures (33-35 °C) is recommended to avoid high temperature cerebral hyperthermia during and after the operation. However, the ideal temperature for uncomplicated adult cardiac surgery is an unsettled question. Typically, the heat exchanger maximum temperature is monitored between 40-42 °C to prevent denaturation of plasma proteins, but studies have not been performed to make these conclusions. Therefore, our hypothesis was to determine the temperature in which blood plasma protein degradation occurs after 2 hours of heat exposure. As a result, blood plasma proteins were exposed to heat in the 37-50 °C range for 2 hours. Plasma protein samples were loaded onto an 8-12% gradient gel for SDS-PAGE and low molecular weight plasma protein degradation was detected with graded heat exposure. Protein degradation was first detected between 43-45 °C of heat exposure. This study supports the practice of monitoring the heat exchanger between 40-42 °C to prevent denaturation of plasma proteins.

First cases of giant pseudocyst complicating inguinal hernia repair

INTRODUCTION

Giant pseudocyst is a rare type of complication following incisional hernia repair and its correct management is still unknown.

MATERIALS AND METHODS

Herein, we describe two unreported cases of giant pseudocyst after inguinal hernia repair. Both patients underwent surgical treatment with partial excision of the pseudocapsule. The two patients were free from recurrence after 6 and 10 months of follow up, respectively.

CONCLUSION

Subtotal surgical removal of the pseudocapsule is a definitive treatment.

Researching special populations: retention of Latino gay and bisexual men and transgender persons in longitudinal health research

Few studies have sought to assess predictors of retention of racial/ethnic or sexual minorities in longitudinal health research. The purpose of this study is to investigate predictors of retention of Latino gay and bisexual men and transgender (GBT) research participants after the baseline interview. Data come from a sample of 643 Latino GBT individuals in two cities (Chicago and San Francisco). We assessed potential predictors of retention (operationalized as successful re-contact) using binary logistic regression of retention on five factors (sociodemographic/health, residential stability, acculturation/attachment to the United States, gay community attachment/stigmatization and research process/design). Our overall follow-up rate was 83 and 80% at 3 and 6 months, respectively. We found that traditional factors (e.g. education, income) were not associated with retention among Latino GBT. The strongest predictors of successful retention were the number of pieces of contact information provided by participants and city of residence (San Francisco). Furthermore, successful methods of contact (i.e. telephone, email) varied by city. We conclude that a largely immigrant urban population of Latino GBT individuals can be successfully followed in longitudinal research. The strong relationship between study design variables and successful retention indicates that collection of thorough contact information is vital to successful follow-up with this population.

Mitral valve prolapse and sudden deafness

To examine the association between MVP and Idiopathic Sudden Sensorineural Hearing loss (ISSNHL). 349 subjects, 86 with ISSNHL and 263 controls underwent a 2D-echocardiography. Patients with ISSNHL had higher rates of MVP (29.1% vs 2.7%, p<0.001), mitral leaflet thickening (15.1% vs 2.3%, p<0.001), mitral regurgitation (16.3% vs 6.5%, p=0.02) and left atrial enlargement (11.6% vs 3.8%, p=0.01). Our results support the hypothesis that MVP could be one of the etiological factors of ISSNHL.

Isolation and characterization of mu-calpain, m-calpain, and calpastatin from postmortem muscle. I. Initial steps

Evidence has indicated that mu-calpain, m-calpain, and calpastatin have important roles in the proteolytic degradation that results in postmortem tenderization. Simple assays of these 3 proteins at different times postmortem, however, has shown that calpastatin and mu-calpain both rapidly lose their activity during postmortem storage, so that proteolytic activity of mu-calpain is nearly zero after 3 d postmortem, even when assayed at pH 7.5 and 25 degrees C, and ability of calpastatin to inhibit the calpains is 30% or less of its ability when assayed at death. m-Calpain, however, retains much of its proteolytic activity during postmortem storage, but the Ca(2+) requirement of m-calpain is much higher than that reported to exist in postmortem muscle. Consequently, it is unclear how the calpain system functions in postmortem muscle. To clarify this issue, we have initiated attempts to purify the 2 calpains and calpastatin from bovine semitendinosus muscle after 11-13 d postmortem. The known properties of the calpains and calpastatin in postmortem muscle have important effects on approaches that can be used to purify them. A hexyl-TSK hydrophobic interaction column is a critical first step in separating calpastatin from the 2 calpains in postmortem muscle. Dot-blot assays were used to detect proteolytically inactive mu-calpain. After 2 column chromatographic steps, 5 fractions can be identified: 1) calpastatin I that does not bind to an anion-exchange matrix, that does not completely inhibit the calpains, and that consists of small polypeptides <60 kDa; 2) calpastatin II that binds weakly to an anion-exchange matrix and that contains polypeptides <60 kDa; all these polypeptides are smaller than the native 115- to 125-kDa skeletal muscle calpastatin; 3) proteolytically active mu-calpain even though very little mu-calpain activity can be detected in zymogram assays of muscle extracts from 11- to 13-d postmortem muscle; this mu-calpain has an autolyzed 76-kDa large subunit but the small subunit consists of 24-, 26- and a small amount of unautolyzed 28-kDa polypeptides; 4) proteolytically active m-calpain that is not autolyzed; and 5) proteolytically inactive mu-calpain whose large subunit is autolyzed to a 76-kDa polypeptide and whose small subunit contains polypeptides similar to the proteolytically active mu-calpain. Hence, loss of calpastatin activity in postmortem muscle is due to its degradation, but the cause of the loss of mu-calpain activity remains unknown.

Exploring the association between anorexia nervosa and geographical latitude

OBJECTIVE

This paper explores the relationship between anorexia nervosa (AN) and climate by mapping the distribution of references of AN in the literature at different latitudes.

METHOD

The distributions of the bibliographic references of two medical disorders -psoriasis and cataracts-, and four mental disorders -AN, anxiety disorders, seasonal affective disorders, and schizophrenia- were mapped according to the institutional affiliation of their first author.

RESULTS

The distribution of references to AN was quite similar to the mental and medical disorders associated to high latitudes, although references to AN were more frequent in the range of 40 masculine-55 masculine in the Northern Hemisphere.

DISCUSSION

The psychosocial and sociocultural features of 'cultures' do not exhaust the factors defining the environment in which we live. Our findings indicate that climatic parameters, such as latitude may be a relevant factor in the occurrence of AN.

Clinical efficacy of anti-pneumococcal vaccination in patients with COPD

BACKGROUND

A study was undertaken to evaluate the clinical efficacy of the 23-valent pneumococcal polysaccharide vaccine (PPV) in immunocompetent patients with chronic obstructive pulmonary disease (COPD).

METHODS

A randomised controlled trial was carried out in 596 patients with COPD of mean (SD) age 65.8 (9.7) years, 298 of whom received PPV. The main outcome was radiographically proven community acquired pneumonia (CAP) of pneumococcal or unknown aetiology after a mean period of 979 days (range 20-1454).

RESULTS

There were 58 first episodes of CAP caused by pneumococcus or of unknown aetiology, 25 in the intervention group and 33 in the non-intervention group. Kaplan-Meier survival curves for CAP did not show significant differences between the intervention and non-intervention arms (log rank test = 1.15, p = 0.28) in the whole group of patients. The efficacy of PPV in all patients was 24% (95% CI -24 to 54; p = 0.333). In the subgroup aged <65 years the efficacy of PPV was 76% (95% CI 20 to 93; p = 0.013), while in those with severe functional obstruction (forced expiratory volume in 1 second <40%) it was 48% (95% CI -7 to 80; p = 0.076). In younger patients with severe airflow obstruction the efficacy was 91% (95% CI 35 to 99; p = 0.002). There were only five cases of non-bacteraemic pneumococcal CAP, all in the non-intervention group (log rank test = 5.03; p = 0.025). Multivariate analysis gave a hazard ratio for unknown and pneumococcal CAP in the vaccinated group, adjusted for age, of 0.20 (95% CI 0.06 to 0.68; p = 0.01).

CONCLUSIONS

PPV is effective in preventing CAP in patients with COPD aged less than 65 years and in those with severe airflow obstruction. No differences were found among the other groups of patients with COPD.

Deep Impact: observations from a worldwide Earth-based campaign

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Unreported sauna use in anorexia nervosa: evidence from the world-wide-web

Weight loss methods employed in anorexia nervosa (AN) are vomiting, laxatives, diuretics, enemas, suppositories, ipecac, weight loss medications and inadequate insulin in diabetics. Some methods result in weight loss from fluid depletion and not a reduction in body fat. Sauna use causes rapid fluid loss, but has not been reported in the medical literature as a weight loss strategy used in AN. We found reports of sauna use in AN on the world-wide-web are rare. We hypothesize that the warming caused by the use of sauna, may result in physical improvement in AN and thereby reduce its acceptability as a weight loss strategy.

Heat in the treatment of patients with anorexia nervosa

The paper presents the results of heat treatment in three cases of anorexia nervosa (AN), in which marked overactivity and/or strenuous exercising were prominent clinical features. Heat was supplied in three ways: continuous exposure to a warm environment, wearing a thermal waistcoat, and sauna baths in an infrared cabin. The outcomes went far beyond what had been expected, as the disappearance of hyperactivity was followed by progressive recovery.

Efficacy and pharmacodynamics of teicoplanin given daily during the first 3 days and then on alternate days for methicillin-resistant Staphylococcus aureus infections

Fifteen evaluable patients (mean age, 67 years) were enrolled to assess the efficacy of teicoplanin, 6 mg/kg given daily during the first 3 days and then on alternate days, for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Eight patients had soft tissue infections, four catheter-associated bacteraemia, two osteomyelitis and one pneumonia. Clinical cure was observed in 13 of 15 patients. Both clinical and bacteriological failures were shown in the two patients with osteomyelitis. The mean serum levels of teicoplanin (mg/L) were 22, 8 and 6.7 for peak, 24 h and 48 h troughs, respectively. The dosage employed in this study proved effective in non-deep-seated MRSA infections.

Increased risk of autoimmune thyroid disease in hepatitis C vs hepatitis B before, during, and after discontinuing interferon therapy

BACKGROUND

Thyroid gland dysfunction has been reported to occur with variable frequency during interferon alfa (IFN-alpha) therapy in patients with the hepatitis C virus (HCV). We prospectively evaluated if the prevalence of autoimmune thyroid disease in patients with HCV differs from that in patients with the hepatitis B virus (HBV) before, at the end of, and 6 months after stopping treatment with IFN-alpha.

METHODS

One hundred thirty-four patients with HCV and 41 patients with HBV were studied. Measurements of serum free thyroxine, free triiodothyronine, thyrotropin, thyroid peroxidase antibodies (TPOAbs), thyroglobulin antibodies (TgAbs), and thyrotropin-binding inhibitory immunoglobulin were performed.

RESULTS

Positive levels of TPOAb and TgAb were found in 20% and 11% of patients with HCV compared with 5% and 3% of patients with HBV, respectively. At the end of IFN-alpha therapy, thyroid gland dysfunction was more prevalent in patients with HCV (12%) compared with those with HBV (3%), with thyrotropin levels significantly higher in the HCV group (P = .03). Titers of TPOAb, TgAb, and thyrotropin-binding inhibitory immunoglobulin increased significantly (P = .02, P = .04, and P = .02, respectively) at the end of IFN-alpha therapy in patients with HCV but not in those with HBV. Patients who developed thyroid gland dysfunction were predominantly female (P = .03), had decreased levels of free triiodothyronine (P<.001), and had a higher prevalence of TPOAb (P = .03) before treatment with IFN-alpha. Thyroid gland dysfunction was reversed in 60% of those with HCV 6 months after discontinuing treatment with IFN-alpha.

CONCLUSIONS

Patients with HCV are more susceptible than patients with HBV to autoimmune thyroid disease. Systematic screening of thyroid gland function and TPOAb titers in all patients with HCV before, during, and after IFN-alpha therapy appears warranted. This precaution is not necessary for patients with HBV.

A three-dimensional virtual model of the head generated from digitalized CT or MR images for anatomical-radiological and neurosurgical evaluations

A computer-generated virtual model has been developed that reconstructs the head in three dimensions from digitalized images obtained with magnetic resonance and computerized tomography. Through programming and the use of commercial graphic animation software, we have developed the whole process of the rotation of the head on different spatial planes. The procedure permits multidirectional anatomical sections to be made on the structure of the head, providing a true dynamic and user-friendly anatomical-radiological atlas. The system serves as a virtual model for the localization of an ideal surgical approach to any lesion thus avoiding possible neurological lesions.

Invasin of Yersinia pseudotuberculosis activates human peripheral B cells

The Yersinia pseudotuberculosis cell surface-located protein invasin was found to promote binding between the pathogen and resting peripheral B cells via beta 1 integrin receptors (CD29). B cells responded by expressing several activation markers and by growing, In contrast, T cells did not react, although these cells express CD29. An isogenic invA mutant failed to activate B cells. The mutation could be complemented by providing the invA+ gene in trans. Purified invasin alone did not activate B cells, although it was able to block the binding of bacteria to the cells.

Dopamine inhibits in vitro release of VIP and proliferation of VIP-immunoreactive pituitary cells

A double immunohistochemical study for VIP and proliferating cell nuclear antigen (PCNA) was carried out on monolayer cultures from adult male rats pituitary glands treated with dopamine (ranging from 10(-9) to 10(-5) M), in order to establish whether or not dopamine is involved in the regulation of the proliferation rate of pituitary VIP-immunoreactive cells. For all doses of dopamine assayed, the release of VIP to the culture medium, the numerical density of VIP-immunoreactive cells and the percentages of VIP- and PCNA-immunoreactive cells decreased significantly after dopamine treatment. These results suggest that dopamine could be a physiological inhibitor involved in the modulation of pituitary VIP proliferation rate.

Isolation and enzymic properties of levansucrase secreted by Acetobacter diazotrophicus SRT4, a bacterium associated with sugar cane

Acetobacter diazotrophicus, a nitrogen-fixing bacterium associated with sugar cane, secretes a levansucrase (sucrose-2,6-beta-D-fructan 6-beta-D-fructosyltransferase; EC 2.4.1.10). This enzyme is constitutively expressed and represents more than 70% of the total proteins secreted by strain SRT4. The purified protein consists of a single 58 kDa polypeptide with an isoelectric point of 5.5. Its activity is optimal at pH 5.0. It catalyses transfructosylation from sucrose to a variety of acceptors including water (sucrose hydrolysis), glucose (exchange reaction), fructan (polymerase reaction) and sucrose (oligofructoside synthesis). In vivo the polymerase activity leads to synthesis of a high-molecular-mass fructan of the levan type. A. diazotrophicus levansucrase catalyses transfructosylation via a Ping Pong mechanism involving the formation of a transient fructosyl-enzyme intermediate. The catalytic mechanism is very similar to that of Bacillus subtilis levansucrase. The kinetic parameters of the two enzymes are of the same order of magnitude. The main difference between the two enzyme specificities is the high yield of oligofructoside, particularly 1-kestotriose and kestotetraose, accumulated by A. diazotrophicus levansucrase during sucrose transformation. We discuss the hypothesis that these catalytic features may serve the different biological functions of each enzyme.

Experience with a new valvulotome for lower-extremity revascularization procedures by the in situ method

Between November 1990 and November 1992, 50 consecutive cases requiring lower-extremity revascularization by the in situ method were compared with regard to use of two different valve cutters, the Hall valvulotome and the Insitucat. There were no amputations in patients with patent grafts, nor were any infections or false aneurysms noted during the course of this study. In the Insitucat group (n = 25), primary patency was achieved in 19 cases. Five of the six graft failures underwent additional procedures of which three remained patent, adding to the secondary patency rate (22 of 25). The greatest problem with regard to maintaining primary graft patency was that of missed or retained valves, but the incidence of this problem decreased during the course of this study as experience was gained with the catheter in conjunction with angioscopy. Experience with the Insitucat valvulotome has demonstrated its efficacy, though enhanced by monitoring the results with angioscopy. The development and discovery of focal stenotic areas and retained valves by surveillance sonography have resulted in enhanced (assisted) primary graft patency rates. The incidence of these problems appears to be comparable with that occurring with other means of producing valvular incompetence for an in situ reconstruction where valvulotomes of similar design are employed. This was confirmed by comparative analysis with another group of 25 in situ vein bypasses performed during the same time period but during the Hall valvulotome.

Morphological findings of an interrelationship among the neurosecretory axons of the neural lobe of the hypophysis

In order to establish whether osmotic stimuli induce variations in the contact regions among neurosecretory axons of the neural lobe of the hypophysis, adult Sprague-Dawley rats of both sexes were treated with furosemide, a diuretic drug. Contacts between adjacent membranes with no condensations of the axolemma but increase in their osmiophilia were observed. After treatment with furosemide interaxonal contacts were significantly increased (p < 0.01, in relation to control animals). Additionally, following treatment with furosemide, axo-axonic synapses among the axons of the neural lobe were found. These findings suggest the existence of interactions among activated neurosecretory axons of the neural lobe of the adult rat.

Changes in the neurosecretory axons of the neural lobe of the hypophysis of rats treated with met-enkephalin. An ultrastructural study

Following administration of met-enkephalin into the third ventricle of rats of both sexes, an ultrastructural-morphometric study was carried out of the neural lobe of the hypophysis, comparing the results with those obtained in untreated animals, controls (injected intraventricularly with distilled water) and animals previously receiving naloxone intraperitoneally. In the untreated and control animals, both males and females, there was a high percentage (about 70%) of neurosecretory axons considered to have a normal morphology; after met-enkephalin administration, this percentage decreased and was accompanied by a rise (slightly more pronounced in the females) in the percentage of degranulated axons and a slight rise in axons with a morphology indicative of regenerative and degenerative phases. Previous administration of the opiate antagonist naloxone led to a rise in the number of axons in the degenerative phase with respect to the other groups of animals; this occurred in both sexes.

Repercussion of craniopharyngioma on the morphology of the rostral wall of the III ventricle. A combined TEM and SEM study

Using a combined scanning and electron microscope technique, the repercussion on the rostral wall of the III ventricle in a patient affected with a retrochiasmatic craniopharyngioma with growth in the ventricular direction were analysed. The apical surface of the ependymocytes was found to be free of cilia, although there were numerous microvilli. The most striking finding appreciated with the scanning electron microscope was the presence of bulbous protrusions towards the lumen of the ventricle; these were formed of cells with shapes, sizes and surface characteristics different from the rest of the ependyma, which appeared flattened. The ultrastructural study revealed the presence of large numbers of filaments and junction complexes both in the ependymal and subependymal cells. Additionally, the protruded zones corresponded to areas showing different degrees of cellular disorganization.

In vitro and in vivo evidence for direct dopaminergic inhibition of VIP-immunoreactive pituitary cells

In order to establish whether dopamine is involved in the regulation of immunocytochemical expression of VIP in pituitary cells, in vivo and in vitro studies were carried out on male rats after treatment with haloperidol and dopamine, respectively. In the in vivo studies, following intraventricular (third ventricle) administration of haloperidol, an increase in the total number of VIP-immunoreactive cells (p < 0.05) was observed; additionally, the cellular, cytoplasmic and nuclear areas were increased (p < 0.01). The in vitro studies demonstrated that dopamine induces a significant decrease (p < 0.05) in the total number of VIP-immunoreactive cells, which were smaller than the cells from the control dishes, because dopamine induces a significant decrease in their cellular, cytoplasmic and nuclear areas (p < 0.01). These results support the hypothesis that dopamine is a physiological inhibitor of pituitary VIP expression and suggest that dopamine modulates the auto- or paracrine effects of VIP in the rat pituitary.