Coadministration of losartan and enalapril exerts additive antiproteinuric effect in IgA nephropathy

Angiotensin-converting enzyme (ACE) inhibitors and AT1-receptor antagonists (ARAs) are widely administered to reduce urinary protein loss and slow the progression of proteinuric nephropathy to end-stage renal failure. Our group recently observed that the combination of ACE inhibitors and ARAs may have an additive antiproteinuric effect, which may occur because ACE inhibitors do not completely reduce angiotensin II (Ang II) production. Ang II is also produced by chymase. Thus, combination therapy better antagonizes the effects of Ang II. The purpose of this study is to ascertain whether the additive antiproteinuric effect of ACE inhibitors plus ARAs is dose dependent and related to the drug-induced reduction in systemic blood pressure. Therefore, enalapril (E; 10 mg/d) and losartan (LOS; 50 mg/d) were randomly administered alone and then in association; initial dosages were doubled when drugs were administered alone and in association. To determine the influence of the drug-dependent effect on reducing blood pressure and the reduction in urinary proteinuria, both ambulatory and office blood pressures were recorded. E and LOS administered alone reduced proteinuria by the same extent; no further reduction was observed when E and LOS alone were administered at a doubled dose. When E and LOS were coadministered, proteinuria decreased by a greater extent compared with E and LOS alone; an additional reduction in proteinuria was observed when combined therapy doses were doubled. The reduction in proteinuria was not correlated with clinical through blood pressure; however, reductions in diastolic and mean ambulatory blood pressures significantly correlated with the decrease in proteinuria, as well as with creatinine clearance. In conclusion, this study shows that combination therapy with E and LOS has an additive dose-dependent antiproteinuric effect that is likely induced by the drug-related reduction in systemic blood pressure. In normotensive proteinuric patients, it is likely that even a small reduction in systemic blood pressure may affect intraglomerular hemodynamics by a great extent because efferent arteriole regulation is hampered more completely by the coadministration of ACE inhibitors and ARAs.

Selective blockade of type-1 metabotropic glutamate receptors induces neuroprotection by enhancing gabaergic transmission

Selective antagonists of mGlu1 (LY367385 and CPCCOEt) and mGlu5 (MPEP) metabotropic glutamate receptors were neuroprotective against NMDA toxicity when either applied to mixed cortical cultures or locally infused into the caudate nucleus. Neuroprotection produced by LY367385 or CPCCOEt was occluded by GABA and was abolished by a cocktail of GABA(A) and GABA(B) receptor antagonists. In contrast, GABAergic drugs did not influence the action of MPEP. In microdialysis studies, LY367385 and CPCCOEt substantially enhanced GABA release in the corpus striatum of freely moving animals, whereas MPEP had no effect on GABA but abolished the stimulation of glutamate release induced by NMDA. A role for mGlu1 receptors in modulating GABAergic transmission was supported by electrophysiological studies carried out in cortico-striatal slices. In this particular model, the mixed mGlu1/5 receptor agonist, DHPG, reduced bicuculline-sensitive inhibitory postsynaptic currents presumably via a presynaptic mechanism. The action of DHPG was antagonized by LY367385, but not by MPEP. Taken together, these results indicate that selective blockade of mGlu1 receptors produces neuroprotection by enhancing GABAergic transmission.

[ANMCO genetic area. Significance of family history in cardiology--Part III]

This is a proposal for collecting the family history throughout a guided form to be given to the patient when awaiting for ambulatory examination or hospital admission, before meeting the cardiologist. In this form, the patient is asked to make an effort in order to focus on his family history (diseases, signs, symptoms, medications, etc.) at least for parents, sibs, and off-springs. A nurse should be committed to give the form to the patient, making him sure that the incomplete filling does not limit the quality of the diagnostic and therapeutic work-up. Thanks to the guided form, the patient concentrates the attention on his family history, eventually consulting the relatives before being examined. The form opens stating that all data are potentially helpful, but none is essential for diagnosis and treatment. This new approach to the family history could support clinicians in having helpful news, only deepening information that seems to be more relevant for the diagnosis.

Colonoscopic removal of a polypoid arteriovenous malformation

A 53-year-old male presenting with a 3-month history of intermittent mild rectal bleeding was found, on double contrast barium enema, to have a large polyp on a long stalk in the sigmoid colon. Large bowel endoscopy confirmed the presence of a 2 cm pedunculated polyp which was removed using a diathermic snare, with slight bleeding following the procedure that did not require endoscopic haemostasis. Only after histologic examination was the polyp shown to be a colonic arteriovenous malformation. Endoscopically, arteriovenous malformations generally appear as flat or elevated bright red lesions. A pedunculated polypoid appearance is extremely uncommon. In this case, no gastrointestinal bleeding or polypoid recurrence was observed during the 12 months of clinical and endoscopic follow-up.

[The Genetic Area of the ANMCO. Family history in modern cardiology: cardiomyopathies -- Part II]

The family history plays an important role in the cardiomyopathy setting. Cardiomyopathies are defined as familial when at least two members of the family are proven as affected. Given that the definition of familial cardiomyopathy has to be evidence-based, the familial forms have to be identified and documented. Detailed family pedigrees are obtained by interviewing patients and relatives and examining all clinical and pathological reports. Then, the clinical non-invasive screening of relatives is proposed, and performed in all informed and consenting relatives. All patients diagnosed with cardiomyopathy are potentially affected by familial forms, until relatives are proven to be unaffected. A few exceptions could be for syndromic disorders for which the phenotypes provide certainty elements/signs analogous to those observed in the proband. Key points for family history interpretation are the phenotype at onset, the time of onset, the presence/absence of coronary risk factors (such as diabetes and hypertension) and concomitant diseases. Special attention has to be paid to neuromuscular disorders that represent a wide heterogeneous issue in which cardiac involvement (cardiomyopathy, arrhythmias and conduction defects) could be the first manifestation of the disease. Based on rigorous investigation, the information derived for each family will provide useful data for present and future management of the family members, and for future research in the field of cardiomyopathies.

Ionic mechanisms underlying differential vulnerability to ischemia in striatal neurons

Brain cells express extremely different sensitivity to ischemic insults. The reason for this differential vulnerability is still largely unknown. Here we discuss the ionic bases underlying the physiological responses to in vitro ischemia in two neostriatal neuronal subtypes exhibiting respectively high sensitivity and high resistance to energy deprivation. Vulnerable neostriatal neurons respond to ischemia with a membrane depolarization. This membrane depolarization mainly depends on the increased permeability to Na+ ions. In contrast, resistant neostriatal neurons respond to ischemia with a membrane hyperpolarization due to the opening of K+ channels. Interestingly, in both neuronal subtypes the ischemia-dependent membrane potential changes can be significantly enhanced or attenuated by a variety of pharmacological agents interfering with intracellular Ca2+ entry, ATP-dependent K+ channels opening, and Na+/Ca2+ exchanger functioning. The understanding of the ionic mechanisms underlying the differential membrane responses to ischemia represents the basis for the development of rational neuroprotective treatments during acute cerebrovascular insults.

[The genetic area of the Italian Association of Hospital Cardiologists. The family history in modern cardiology--part I]

The family history constitutes the first step in the cardiologist's clinical approach to the patient and is highly informative both for monogenic and multifactorial disorders. A detailed interview is a time-consuming activity: in their daily practice, cardiologists may have 10, 20 or more interviews to complete. The patient tends to concentrate his attention on his own clinical history, rather than on that of his family, and explaining the importance of the role of a well analyzed family history in the modern cardiology can be difficult and may further increase the loss of time. However, the information about a given phenotype revealed by a detailed and non-confounding family history is essential to define the inheritance of monogenic diseases, to calculate the penetrance, even when the disease genes are unknown, or to evaluate "clinically cryptic" risks in multifactorial diseases. The Genetic Area of the Italian Association of Hospital Cardiologists proposes a novel approach to the family history of the patients: a guide form to be filled in by the patient whilst awaiting for clinical evaluation or immediately after admission to the cardiology department. The proposal will be articulated in three parts: one dedicated to general considerations on the confounding or incomplete evaluation of potentially useful data from the family history, one specifically dedicated to cardiomyopathies, and one containing a model of the form to be eventually adopted by the cardiological scientific societies.

Functional coexpression of excitatory mGluR1 and mGluR5 on striatal cholinergic interneurons

The group I mGluR agonist (S)-3,5-dihydroxyphenylglycine (3,5-DHPG) and the mGluR5 agonist 2-chloro-5-hydroxyphenylglycine both induced a membrane depolarisation of striatal cholinergic interneurons. The response to 3,5-DHPG was blocked only by the coadministration of mGluR1 and mGluR5 antagonists, suggesting that both mGluRs are involved in this excitatory effect in striatal cholinergic interneurons.

Oral tacrolimus long-term therapy in patients with Crohn's disease and steroid resistance

AIM

To report the results of a prospective, open-label, uncontrolled study in 13 patients affected by Crohn's disease with resistance to steroids.

METHODS

The patients were treated long-term with oral tacrolimus, aiming to both resolve acute attacks and maintain remission. Tacrolimus was administered at the dose of 0.1--0.2 mg.day/kg and adjusted in order to achieve levels of 5--10 ng/mL; only mesalazine was continued concomitantly. Steroids and total parenteral nutrition were tapered when appropriate.

RESULTS

Median treatment was 27.3 months. Only one patient dropped out due to adverse events. Crohn's disease activity index score significantly decreased after 6 months in 11 patients; for 1 year in nine of them, and 7 years in two of them. The inflammatory bowel disease life-quality questionnaire score significantly increased over the same periods. A marked drop in hospitalizations was recorded. In three out of six patients complete closure of fistulas occurred. Tacrolimus allowed total parenteral nutrition to be withdrawn in three out of five patients. Supplementation with low-dose steroids was required in five patients. Two patients underwent surgery.

CONCLUSIONS

Tacrolimus therapy appears to be associated with both short- and long-term benefits, and may represent a therapeutic option in Crohn's disease when conventional therapies fail. This study encourages its use in controlled trials.

Cell-type specificity of mGluR activation in striatal neuronal subtypes

The effects of metabotropic glutamate receptor (mGluR) activation were studied in medium spiny neurons and large aspiny (LA) interneurons by means of electrophysiological and optical recordings. DCG-IV and L-SOP, agonists for group II and III mGluRs, respectively, produced a presynaptic inhibitory effect on corticostriatal glutamatergic excitatory postsynaptic potentials (EPSPs) in both spiny and LA cells. Activation of group I mGluRs by the selective agonist 3,5-DHPG produced no effect on membrane properties and glutamatergic transmission in spiny neurons, whereas it did cause a membrane depolarization in LA interneurons coupled to increased input resistance. In combined optical and electrophysiological experiments, in spiny neurons 3,5-DHPG enhanced membrane depolarization and intracellular calcium (Ca2+) levels induced by NMDA applications, but not in LA interneurons. These data suggest the existence of a positive interaction between NMDA and group I mGlu receptors only in medium spiny cells which might, at least partially, account for the differential vulnerability to excitotoxic damage observed in striatal neuronal subtypes.

Stimulation of nitric oxide-cGMP pathway excites striatal cholinergic interneurons via protein kinase G activation

Conflicting data have been collected so far on the action of nitric oxide (NO) on cholinergic interneurons of the striatum. In the present in vitro electrophysiological study, we reported that intracellularly recorded striatal cholinergic interneurons are excited by both hydroxylamine and S-nitroso-N-acetylpenicillamine, two NO donors. This excitation persisted unchanged in the presence of glutamate, dopamine, and substance P receptor antagonists as well as after blockade of tetrodotoxin (TTX)- and calcium channel-sensitive transmitter release, suggesting that NO produces its effects by modulating directly resting ion conductances in the somatodendritic region of striatal cholinergic cells. The depolarizing effect of hydroxylamine was greatly reduced by lowering external concentrations of sodium ions (from 126 to 38 mm) and did not reverse polarity in the voltage range from -120 to -40 mV. The sodium transporter blockers bepridil and 3',4'-dichlorobenzamil were conversely ineffective in preventing NO-induced membrane depolarization. Intracellular cGMP elevation is required for the action of hydroxylamine on striatal cholinergic cells, as demonstrated by the findings that the membrane depolarization produced by this pharmacological agent was prevented by bath and intracellular application of two inhibitors of soluble guanylyl cyclase and was mimicked and occluded by zaprinast, a cGMP phosphodiesterase inhibitor. Finally, intracellular Rp-8-Br-cGMPS, a protein kinase G (PKG) inhibitor, blocked the hydroxylamine-induced membrane depolarization of cholinergic interneurons, whereas both okadaic acid and calyculin A, two protein phosphatase inhibitors, enhanced it, indicating that intracellular PKG and phosphatases oppositely regulate the sensitivity of striatal cholinergic interneurons to NO. The characterization of the cellular mechanisms involved in the regulation of striatal interneuron activity is a key step for the understanding of the role of these cells in striatal microcircuitry.

Role of tonically-active neurons in the control of striatal function: cellular mechanisms and behavioral correlates

1. The striatum is primarily involved in motor planning and motor learning. Human diseases involving its complex circuitry lead to movement disorders such as Parkinson's disease (PD) and Huntington's disease (HD). Moreover the striatum has been involved in processes linked to reward, cognition and drug addiction. 2. The high content of acetylcholine (ACh) found in the striatum is due to the presence of cholinergic interneurons. The intrinsic electrical and synaptic properties of these interneurons have been recently characterized. However, their functional significance is far from being fully elucidated. 3. In vivo electrophysiological experiments from behaving monkeys have identified these cholinergic interneurons as "Tonically Active Neurons" (TANs). They are activated by presentation of sensory stimuli of behavioral significance or linked to reward. 4. Experimental evidence showed that integrity of the nigrostriatal dopaminergic system is essential for TANs to express learned activity. 5. PD is known to be due to the loss of the nigrostriatal dopaminergic pathway and the ensuing imbalance between the content of dopamine and acetylcholine in the striatum. This evidence supports the hypothesis that cholinergic interneurons, or TANs, play a key role in the modulation of striatal function.

[Pituitary pathology in elderly patients admitted in a division of internal medicine. Description of 3 cases]

Pituitary diseases are often unrecognized in the elderly, although if they can be at the basis of several pathological conditions. We report three clinical cases. Patient n. 1: 87 years old woman, in poor general condition. Thyroid function evaluation showed secondary hypothyroidism. Subsequent pituitary function evaluation demonstrated hypopituitarism with empty sella. The diagnosis was "hypopituitarism with secondary hypothyroidism and adrenocortical insufficiency, in empty sella" starting substitutive treatment with glucocorticoids and L-thyroxine, with improvement in her clinical conditions. Patient n. 2: 74 years old woman, with severe congestive heart failure. Her clinical history revealed hypothyroidism. An endocrine evaluation (in absence of therapy) demonstrated panhypopituitarism with secondary hypothyroidism and adrenocortical insufficiency in presence of empty sella. The patients was started on substitutive treatment and her conditions improved. Patient n. 3: 74 years old man with several atrial fibrillation episodes and hyperthyroidism. Thyroid function evaluation suggested secondary hyperthyroidism confirmed by the presence of a pituitary macroadenoma. The patient underwent surgical adenomectomy by trans-sphenoidal route. The clinical conditions of the patient improved, but a slight secondary hyperthyroidism was still present caused by the persistence of residual pathological tissue in the right cavernous sinus region confirmed by octreoscan suggesting the presence of a lesion endowed with somatostatin receptors. The patient was started on long acting octreotide treatment, which is still in progress. In conclusion, pituitary diseases pass often unrecognized in the elderly. Their prompt recognition and treatment can resolve dangerous situations for the patients.

Ultrastructural study of the conjunctival epithelium in the Mongolian gerbil (Meriones unguiculatus)

The conjunctival epithelium of the Mongolian gerbil (Meriones unguiculatus) was studied using the transmission and scanning electron microscopy. The superficial cells of the conjunctival epithelium were isoprismatic in shape and were covered, on their luminal surface, with microplicae. They were connected with the adjacent cells by junctional complexes and desmosomes. Some of the superficial cells were partially or completely detached from the underlying intermediate cells: this morphological pattern was interpreted as an expression of cellular renewal of the conjunctival surface. Goblet cells were either isolated or gathered in clusters: in any case, they were firmly connected with the adjacent epithelial cells. The apical part of the goblet cells was covered with a great number of long microvilli: they showed a variety of morphological aspects, which were interpreted as occurring in a sequential pattern during the secretory process. The Mongolian gerbil can be considered among the laboratory animals used for ophthalmic research.

Anatomical and psychological mechanism of reduplicative misidentification syndromes

Reduplicative misidentifications syndromes (RMS) are rare memory disorders characterized by the subjective conviction that a place, person or event is duplicated. Even if RMS often follow a right frontal lesion, several studies have stressed the importance of bilateral hemispheric pathology. Moreover, from a psychological perspective, there is uncertainty if this symptom should be considered just as a kind of confabulation or if it should be associated with personal psychosocial and behavioral aspects. We report a patient who developed normal pressure hydrocephalus and RMS one year after a post-traumatic right frontal lesion. At the first neuropsychological evaluation, we found mild impairment of all functions, associated with the presence of reduplicative paramnesia. After the ventricle-peritoneal shunt intervention, we observed a progressive improvement of all functions but the frontal ones. The memory deficit became less specific and the RMS disappeared. We therefore postulate that a focal right frontal lesion is not sufficient to cause RMS per se. Our clinical report suggests that paramnesic events held on reasonable ground, not being just a kind of confabulation.

Synaptic transmission in the striatum: from plasticity to neurodegeneration

Striatal neurones receive myriad of synaptic inputs originating from different sources. Massive afferents from all areas of the cortex and the thalamus represent the most important source of excitatory amino acids, whereas the nigrostriatal pathway and intrinsic circuits provide the striatum with dopamine, acetylcholine, GABA, nitric oxide and adenosine. All these neurotransmitter systems interact each other and with voltage-dependent conductances to regulate the efficacy of the synaptic transmission within this nucleus. The integrative action exerted by striatal projection neurones on this converging information dictates the final output of the striatum to the other basal ganglia structures. Recent morphological, immunohistochemical and electrophysiological findings demonstrated that the striatum also contains different interneurones, whose role in physiological and pathological conditions represents an intriguing challenge in these years. The use of the in vitro brain slice preparation has allowed not only the detailed investigation of the direct pre- and postsynaptic electrophysiological actions of several neurotransmitters in striatal neurones, but also the understanding of their role in two different forms of corticostriatal synaptic plasticity, long-term depression and long-term potentiation. These long-lasting changes in the efficacy of excitatory transmission have been proposed to represent the cellular basis of some forms of motor learning and are altered in animal models of human basal ganglia disorders, such as Parkinson's disease. The striatum also expresses high sensitivity to hypoxic-aglycemic insults. During these pathological conditions, striatal synaptic transmission is altered depending on presynaptic inhibition of transmitter release and opposite membrane potential changes occur in projection neurones and in cholinergic interneurones. These ionic mechanisms might partially explain the selective neuronal vulnerability observed in the striatum during global ischemia and Huntington's disease.

A new rat model of small vessel stenting

OBJECTIVES

Restenosis is the major complication of coronary angioplasty and stenting. In addition, the small vessel diameter represents a major limitation to the wide use of the technology. The aim of this study was to assess the feasibility and the vascular response of stent deployment in rat small vessels.

METHODS

In 40 Wistar rats (500-550 g) a Nir stent crimped on a 1.5 mm Comet angioplasty balloon catheter was deployed at high pressure in the common carotid artery. Neointimal area, neointima/media ratio and the arterial dimension were assessed immediately and at 7, 14, 21, and 28 days after stenting.

RESULTS

After stent deployment, the neointimal area and the neointima/media ratio increased progressively and peaked at 14 days (p < 0.05 vs 0 and 7 days). Alpha-actin-positive cells were found circumferentially organized on the lumen surface. At 21 and 28 days after stenting, the neointima and the neointima/media ratio were not statistically different compared with the results obtained fourteen days after stent deployment. No significant differences in the area of external elastic lamina were observed during the study period. In contrast, the internal lumen area was reduced significantly at 14, 21, and 28 days after the stent deployment. Subacute thrombosis rate after stent implantation was 26.5 %.

CONCLUSIONS

The results of this study demonstrated that the balloon expandable stents can be safely placed into rat arteries and the reduction of the internal arterial lumen observed after stent deployment was only due to the neointima formation whereas remodeling did not occur.

Involvement of intracellular calcium stores during oxygen/glucose deprivation in striatal large aspiny interneurons

Striatal large aspiny interneurons were recorded from a slice preparation using a combined electrophysiologic and microfluorometric approach. The role of intracellular Ca2+ stores was analyzed during combined oxygen/glucose deprivation (OGD). Before addressing the role of the stores during energy deprivation, the authors investigated their function under physiologic conditions. Trains of depolarizing current pulses caused bursts of action potentials coupled to transient increases in intracellular calcium concentration ([Ca2+]i). In the presence of cyclopiazonic acid (30 micromol/L), a selective inhibitor of the sarcoendoplasmic reticulum Ca2+ pumps, or when ryanodine receptors were directly blocked with ryanodine (20 [micromol/L), the [Ca2+]i transients were progressively smaller in amplitude, suggesting that [Ca2+]i released from intracellular stores helps to maintain a critical level of [Ca2+]i during physiologic firing activity. As the authors have recently reported, brief exposure to combined OGD induced a membrane hyperpolarization coupled to an increase in [Ca2+]i. In the presence of cyclopiazonic acid or ryanodine, the hyperpolarization and the rise in [Ca2+]i induced by OGD were consistently reduced. These data support the hypothesis that Ca2+ release from ryanodine-sensitive Ca2+ pools is involved not only in the potentiation of the Ca2+ signals resulting from cell depolarization, but also in the amplification of the [Ca2+]i rise and of the concurrent membrane hyperpolarization observed in course of OGD in striatal large aspiny interneurons.

Activation of D2-like dopamine receptors reduces synaptic inputs to striatal cholinergic interneurons

Dopamine (DA) plays a crucial role in the modulation of striatal function. Striatal cholinergic interneurons represent an important synaptic target of dopaminergic fibers arising from the substantia nigra and cortical glutamatergic inputs. By means of an electrophysiological approach from corticostriatal slices, we isolated three distinct synaptic inputs to cholinergic interneurons: glutamate-mediated EPSPs, GABAA-mediated potentials, and Acetylcholine (ACh)-mediated IPSPs. We therefore explored whether DA controls the striatal cholinergic activity through the modulation of these synaptic potentials. We found that SKF38393, a D1-like receptor agonist, induced a membrane depolarization (also see Aosaki et al., 1998) but had no effects on glutamatergic, GABAergic, and cholinergic synaptic potentials. Conversely, D2-like DA receptor activation by quinpirole inhibited both GABAA and cholinergic synaptic potentials. These effects of quinpirole were mimicked by omega-conotoxin GVIA, blocker of N-type calcium channels. The lack of effect both on the intrinsic membrane properties and on exogenously applied GABA and ACh by quinpirole supports a presynaptic site of action for the D2-like receptor-mediated inhibition. Moreover, the quinpirole-induced decrease in amplitude was accompanied by an increase in paired pulse facilitation ratio (EPSP2/EPSP1), an index of a decrease in transmitter release. Our findings demonstrate that DA modulates the excitability of cholinergic interneurons through either an excitatory D1-like-mediated postsynaptic mechanism or a presynaptic inhibition of the GABAergic and cholinergic inhibitory synaptic potentials.

Acetylcholine-mediated modulation of striatal function

Striatal spiny neurones serve as a major anatomical locus for the relay of cortical information flow through the basal ganglia. these projection neurones also represent the main synaptic target of cholinergic interneurones, whose physiological role in striatal activity still remains largely enigmatic. The striatal cholinergic system has been implicated in the pathophysiology of movement disorders such as Parkinson's disease, but the cellular mechanisms underlying cholinergic-neurone function are still unknown. On the basis of in vitro electrophysiological evidence, obtained from a rat corticostriatal-slice preparation, we propose that endogenous ACh exerts a complex modulation of striatal synaptic transmission, which produces both short-term and long-term effects. ACh-mediated mechanisms might be of crucial importance in processing the cortical inputs to the striatum.

Oral tacrolimus (FK 506) in Crohn's disease complicated by fistulae of the perineum

We describe the cases of two patients with Crohn's disease affected by severe perineal fistulae resistant to conventional therapies, successfully treated with FK 506, a new immunomodulatory drug. It is well absorbed from diseased bowel and preliminary experiences have indicated its short-term use in complicated Crohn's disease. The first patient was a 24-year-old male with perineal fistula and severe skin ulceration (8 cm of external opening diameter). He had undergone colectomy and ileostomy because of severe pancolitis refractory to medical treatment and had been treated with azathioprine and metronidazole. Two months after starting FK 506, a dramatic improvement made further surgical operation unnecessary. Local and general benefit was observed during the following 26 months, until FK 506 was withdrawn. The second patient was a 28-year-old male with a diagnosis of ulcerative pancolitis changed to Crohn's disease two months after the onset of a perineal fistula, recurring despite drainage procedures, steroid therapy, and total parenteral nutrition. FK 506 was administered for two months with a complete healing of fistula. Successively, it was stopped and corticosteroids (associated to enteral nutrition) were given because of recurrent rectal bleeding. Our experience encourages the use of oral FK 506 in complicated Crohn's disease and suggests the possibility of a long-term primary therapy other than the use as a "bridge" to other treatments.

Effects of hydroxymethylglutaryl coenzyme A reductase inhibitor simvastatin on smooth muscle cell proliferation in vitro and neointimal formation in vivo after vascular injury

OBJECTIVES

We sought to evaluate the effects of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on vascular smooth muscle cell (VSMC) proliferation in vitro and neointimal formation in vivo after vascular injury.

BACKGROUND

Neointimal hyperplasia after vascular injury is responsible for restenosis after arterial stenting, whereas arterial remodeling and neointimal formation are the causes of restenosis after percutaneous transluminal coronary angioplasty.

METHODS

We assessed the effect of simvastatin on in vitro VSMC proliferation. To study the effects of simvastatin in vivo, balloon injury and stent deployment were performed in the common carotid artery of rats. Neointimal area was measured two weeks later in the balloon injury model and three weeks after stent deployment.

RESULTS

Simvastatin markedly inhibits VSMC proliferation in vitro. In vivo, simvastatin reduced, in a dose-dependent manner, the neointimal area and the neointima-media ratio after balloon injury from 0.266 +/- 0.015 mm2 to 0.080 +/- 0.026 mm2 and from 1.271 +/- 0.074 to 0.436 +/- 0.158 (p < 0.001 vs. control rats) at the highest dose. Simvastatin also significantly reduced the neointimal formation and the neointima-media ratio after stenting from 0.508 +/- 0.035 mm2 to 0.362 +/- 0.047 mm2 (p < 0.05 vs. control rats) and from 2.000 +/- 0.136 to 1.374 +/- 0.180 (p < 0.05 vs. control rats). The vessel thrombosis rate after stent deployment was 30% in the control group and 11.1% in the treated group (p = NS). Moreover, the systemic administration of simvastatin did not affect hepatic and renal functions, blood pressure or heart rate.

CONCLUSIONS

Simvastatin potently inhibits VSMC proliferation in vitro and reduces neointimal formation in a rat model of vascular injury.

Pharmacological inhibition of the Na(+)/Ca(2+) exchanger enhances depolarizations induced by oxygen/glucose deprivation but not responses to excitatory amino acids in rat striatal neurons

BACKGROUND AND PURPOSE

Neuronal Na(+)/Ca(2+) exchanger plays a relevant role in maintaining intracellular Ca(2+) and Na(+) levels under physiological and pathological conditions. However, the role of this exchanger in excitotoxicity and ischemia-induced neuronal injury is still controversial and has never been studied in the same neuronal subtypes.

METHODS

We investigated the effects of bepridil and 3',4'-dichlorobenzamil (DCB), 2 blockers of the Na(+)/Ca(2+) exchanger, in rat striatal spiny neurons by utilizing intracellular recordings in brain slice preparations to compare the action of these drugs on the membrane potential changes induced either by oxygen and glucose deprivation (OGD) or by excitatory amino acids (EAAs).

RESULTS

Bepridil (3 to 100 micromol/L) and DCB (3 to 100 micromol/L) caused a dose-dependent enhancement of the OGD-induced depolarization measured in striatal neurons. The EC(50) values for these effects were 31 micromol/L and 29 micromol/L, respectively. At these concentrations neither bepridil nor DCB altered the resting membrane properties of the recorded cells (membrane potential, input resistance, and current-voltage relationship). The effects of bepridil and DCB on the OGD-induced membrane depolarization persisted in the presence of D-2-amino-5-phosphonovalerate (50 micromol/L) plus 6-cyano-7-nitroquinoxaline-2,3-dione (20 micromol/L), which suggests that they were not mediated by an enhanced release of EAAs. Neither tetrodotoxin (1 micromol/L) nor nifedipine (10 micromol/L) affect the actions of these 2 blockers of the Na(+)/Ca(2+) exchanger, which indicates that voltage-dependent Na(+) channels and L-type Ca(2+) channels were not involved in the enhancement of the OGD-induced depolarization. Conversely, the OGD-induced membrane depolarization was not altered by 5-(N, N-hexamethylene) amiloride (1 to 3 micromol/L), an inhibitor of the Na(+)/H(+) exchanger, which suggests that this antiporter did not play a prominent role in the OGD-induced membrane depolarization recorded from striatal neurons. Bepridil (3 to 100 micromol/L) and DCB (3 to 100 micromol/L) did not modify the amplitude of the excitatory postsynaptic potentials evoked by cortical stimulation. Moreover, these blockers did not affect membrane depolarizations caused by brief applications of glutamate (0.3 to 1 mmol/L), AMPA (0. 3 to 1 micromol/L), and NMDA (10 to 30 micromol/L).

CONCLUSIONS

These results provide pharmacological evidence that the activation of the Na(+)/Ca(2+) exchanger exerts a protective role during the early phase of OGD in striatal neurons, although it does not shape the amplitude and the duration of the electrophysiological responses of these cells to EAA.