Impella recover 100 microaxial left ventricular assist device: the Niguarda experience

BACKGROUND

The Impella Recover 100 (IR100) is an intravascular microaxial blood pump used to support blood circulation for a maximum of 7 days in cases of reduced left ventricular function, for example in postcardiotomy low output syndrome or in cardiogenic shock after acute myocardial infarction.

MATERIALS AND METHODS

We supported five patients with the IR100. The mean age, cardiac index (CI), and ejection fraction (EF) of our population were 42 years, 1.83 L/min/m(2), and 20%, respectively. Two patients (group A) with ischemic dilated cardiomyopathy were bridged to heart transplant. Two patients (group B) with fulminan myocarditis and septic shock were bridged to recovery. One patient, with severe valvular cardiomyopathy who underwent aortic valve replacement and mitral valve annuloplasty, was supported to weaning from ECC.

RESULTS

Mean support time was 9.8 +/- 2.3 days. Only one acute myocarditis patient died from a severe vasoplegic syndrome despite maximal inotropic and vasoactive support. Both group A patients were successfully transplanted. Among group B, the second patient resolved the septic status and was slowly weaned from the device and discharged home with moderate improvement of LV function (EF = 40%). Patient C was weaned from the IR100 and electively placed on the heart transplant recipient list.

CONCLUSIONS

IR100 is a device that in our experience can be utilized for various indications for short-term support. In compromised patients where a traditional LVAD is contraindicated, the IR100 showed good results, for it is minimally invasive and does not need ECC or systemic anticoagulation.

α-Glycerylphosphorylethanolamine rescues astrocytes from mitochondrial impairment and oxidative stress induced by amyloid β-peptides

The present work shows that alpha-glycerylphosphorylethanolamine (alpha-GPE) is effective in recovering astrocytes from mitochondrial membrane integrity and potential derangement and cellular oxidative stress that occur under amyloid beta-peptides-induced reactive gliosis.alpha-Glycerylphosphorylethanolamine (alpha-GPE), a new compound with nootropic properties, known to improve in vivo the learning and memory processes, has been tested for its protective properties on an in vitro model of degeneration. Rat primary astrocytic cultures treated with two amyloid-derived peptides, Abeta((1-40)) and Abeta(3(pE)-42), showed a marked reduction of the mitochondrial redox activity and membrane potential, together with an increase of oxidative species production. Plasma membrane lipid peroxidation (LPO) as well as generation of peroxides is greatly increased under Abeta-peptides toxicity. These features, typical of the reactive gliosis that accompanies neuronal degeneration, were readily recovered by pretreatment with alpha-GPE. alpha-GPE, likely improving the fluidity of cell membrane, has the potential to recover astrocytes from the general redox derangement induced by different amyloid fragments and possibly to protect from inflammation, gliosis and neurodegeneration. This is the first evidence of an antioxidant effect of the ethanolamine derivative on a rat model of chronic gliosis.

The problematic issue of Kufs disease diagnosis as performed on rectal biopsies: a case report

Kufs disease, the late-onset form of a group of neurodegenerative disorders, known as the neuronal ceroid-lipofuscinoses, is characterized by intraneuronal/extraneuronal accumulation of proteins that are visible as fingerprint inclusions and granular osmiophilic deposits (GRODs) at the ultrastructural level. A problematic case of Kufs disease in a 53-year-old female affected by progressive gait disturbances, myoclonus, epilepsy, and profound dementia is presented. Laboratory, biochemical, and molecular genetic tests were unremarkable. A magnetic resonance imaging of the brain revealed a moderate atrophy over both hemispheres with no white matter changes. Ultrastructural examination of rectal mucosa biopsies showed fingerprint inclusions in perivascular smooth muscle cells. Pathological examination of autoptic tissues showed numerous intraneuronal PAS-positive, diastase-resistant inclusions corresponding to GRODs at the ultrastructural examination, but no fingerprint inclusions. Cerebellum, skeletal, and cardiac muscles, skin, and liver were unaffected. The present case illustrates the diagnostic difficulties encountered while examining Kufs disease pathological samples. Main problematic issues include (1) specificity and diagnostic value of fingerprint inclusions when found exclusively in perivascular smooth muscle cells; (2) safe distinction of GRODs from lipofuscin inclusions in cerebral tissue; and (3) reliability in using extraneural tissues and, in particular, rectal mucosa biopsies for diagnostic purposes.

Plasma channels produced by a laser-triggered high-voltage discharge

A plasma waveguide scheme for high-intensity laser guiding with densities and lengths suitable for laser-plasma particle accelerators is presented. This scheme uses a laser-triggered high-voltage discharge, presents negligible jitter, allows full access to the plasma, and can be scaled to large distances. Experimental results showing the feasibility of this scheme are presented.

BACE-2 is overexpressed in Down's syndrome

Brain deposition of the amyloid-beta protein (Abeta) is a frequent complication of Down's syndrome (DS) patients. Abeta peptide is generated by endoproteolytic processing of Abeta precursor protein by gamma and beta secretases. Recently a transmembrane aspartyl protease, BACE, has been identified as the beta-secretase, and its homologous BACE-2 has also been described. BACE-2 gene resides on chromosome 21 in the obligate DS region. It cleaves Abeta precursor protein at its beta site and more efficiently at a different site within Abeta. In the present study we characterized the BACE-2 gene and protein expression in the DS patients and healthy control. We analyzed, by using a nonradioactive ribonuclease protection assay, the levels of BACE-2 mRNA expression in primary skin fibroblasts. The analysis revealed a 2.6-fold increase in BACE-2 mRNA levels in the DS group compared to the levels observed in the control group. Western blot analysis revealed no difference between DS and control in BACE-2 protein levels in the intracellular compartment. In the medium conditioned by fibroblast, we revealed an evident secretion of BACE-2 protein, represented by two different molecular weights, remarkably increased in DS fibroblasts. BACE-2 overexpression was also confirmed in the DS fetal brains and human neural embryonic DS stem cells in which conditioned media BACE-2 was secreted. These data highlight the importance of the extracellular compartment where BACE-2 overexpression could play a role in plaque formation in DS patients.

Combined surgical approach to coexistent carotid and coronary artery disease: early and late results

BACKGROUND

The management of patients with simultaneous coronary artery and carotid artery disease is still controversial.

METHODS

A retrospective review of the records and follow-up data of 139 consecutive patients undergoing simultaneous coronary artery bypass graft and carotid endarterectomy from 1981 to 1999 was carried out.

RESULTS

Early mortality was 2.1%, perioperative myocardial infarction and stroke rates were 2.8 and 1.4%, respectively. Survival at 7 years was 74.7+/-5.1% and event-free survival at 7 years was 67.9+/-5.6%.

CONCLUSIONS

The combined surgical approach has proved to be effective and safe allowing the treatment of both diseases in a single operative procedure.

Acetaminophen protects hippocampal neurons and PC12 cultures from amyloid beta-peptides induced oxidative stress and reduces NF-kappaB activation

The present findings show that an atypical non-steroidal anti-inflammatory drug, such as acetaminophen, retains the ability to recover amyloid beta-peptides driven neuronal apoptosis through the impairment of oxidative stress. Moreover, this compound reduces the increased NF-kappaB binding activity, which occurs in these degenerative conditions. Therapeutic interventions aimed at reducing the inflammatory response in Alzheimer's disease (AD) recently suggested the application of non-steroidal anti-inflammatory drugs. Although the anti-inflammatory properties of acetaminophen are controversial, it emerged that in an amyloid-driven astrocytoma cell degeneration model acetaminophen proved to be effective. On these bases, we analyzed the role of acetaminophen against the toxicity exerted by different Abeta-peptides on rat primary hippocampal neurons and on a rat pheochromocytoma cell line. We found a consistent protection from amyloid beta-fragments 1-40 and 1-42-induced impairment of mitochondrial redox activity on both cell cultures, associated with a marked reduction of apoptotic nuclear fragmentation. An antioxidant component of the protective activity emerged from the analysis of the reduction of phospholipid peroxidation, and also from a significant reduction of cytoplasmic accumulation of peroxides in the pheochromocytoma cell line. Moreover, activation of NF-kappaB by amyloid-derived peptides was greatly impaired by acetaminophen pre-treatment in hippocampal cells. This evidence points out antioxidant and anti-transcriptional properties of acetaminophen besides the known capability to interfere with inflammation within the central nervous system, and suggests that it can be exploited as a possible therapeutic approach against AD.

Expression in E. coli and purification of recombinant fragments of wild type and mutant human prion protein

Prion diseases are fatal neurodegenerative disorders of the CNS of men and animals, characterized by spongiform degeneration of the CNS, astrogliosis and deposition of amyloid into the brain. The conversion of a cellular glycoprotein (the prion protein, PrP(C)) into an altered isoform (the prion scrapie, PrP(Sc)), which accumulates within the brain tissue by virtue of its resistance to the intracellular catabolism, is currently believed to represent the etiologic agent responsible for these diseases. Synthetic or recombinant polypeptides are commonly used to elucidate the mechanism of proteins involved in neurodegenerative diseases. Here we describe a procedure, which allows the synthesis and purification in its native folding, of the human prion protein fragment 90-231, corresponding to the protease resistant core of PrP(Sc). We synthesized the polypeptides 90-231 of both the wild type and the E200K mutant isoforms of PrP. Using a gluthatione S-transferase (GST) fusion protein approach, milligram amounts of polypeptides were obtained after expression in E. coli. The recovery of the purified fusion protein was monitored following the evaluation of the GST activity. The PrP fragment was released from the fusion protein immobilized on a glutathione-coupled agarose resin by direct cleavage with thrombin. The recombinant protein was identified by comassie stained acrylamide gel and by immunoblotting employing a monoclonal anti-PrP antibody. The peptide purified by gel filtration chromatography showed mainly an alpha-helix structure, as analysed by circular dichroism (CD) and an intact disulfide bridge. The same procedure was also successfully employed to synthesize and purify the E200K mutant PrP fragment.

High-dose idarubicin and busulphan as conditioning for autologous stem cell transplantation in acute myeloid leukemia: a feasibility study

INTRODUCTION

Between 30 and 50% of patients with acute myeloid leukemia still relapse after autologous stem cell transplantation. We investigated the feasibility of a new conditioning regimen consisting of high dose IDA plus oral busulphan in patients undergoing autologous transplantation.

MATERIALS AND METHODS

Patients (n = 13) were given three days continuous infusion IDA, followed by four days conventional dose oral busulphan as conditioning. Peripheral blood stem cells were used in all cases. Eleven patients were in CR1. Patients with t(8;21) and inv(16) as well as those with acute promyelocytic leukemia were excluded from the study. The median of CD34+ cells infused was 6.2 x 10(6)/l (2.6-16.1).

RESULTS

No case of transplant-related mortality occurred. The median number of days to neutrophil (>0.5 x 10(9)/l) and platelet (>20 x 10(9)/l) recovery was 10 (7-21) and 20 (9-26), respectively. Patients needed a median of 3 platelet units (1-6) and 3 blood units (0-12), respectively. Left ventricular ejection fraction remained unmodified after ASCT. Twelve out of 13 patients (92%) had variable grade of mucositis (two grade 2, five grade 3 and five grade 4). Total parenteral nutrition was needed in nine patients (69%). After a median follow-up of 14 months from ASCT, 11 patients out of 13 (85%) are alive in continuous CR; the other two patients experienced relapse at 12 and 14 months.

CONCLUSION

Our data demonstrate the feasibility of a conditioning regimen based on high-dose IDA plus Busulphan in AML. Results concerning antileukemic efficacy are promising, but need confirmation on larger series with longer follow-up.

Aorto-atrial fistula through the septum in recurrent aortic dissection

A case of aortic dissection (De Bakey type I) with a fistula to the right atrium through the interatrial septum, diagnosed by transthoracic and transesophageal echocardiography is reported. The patient presented with cardiac failure and a continuous murmur in the right second and third intercostal spaces. The patient underwent successful operative repair.

First successful Italian clinical experience with DeBakey VAD

The growing number of patients waiting for heart transplantation more than tripled between 1989 and 1998. Various non-pulsatile mechanical circulatory support devices have been developed as bridge to heart transplantation in recent years. We report the first successful Italian clinical experience with an axial-flow pump, DeBakey VAD, in a patient supported as bridge to transplantation for 55 days.

Tricuspid regurgitation secondary to mitral valve disease: tricuspid annulus function as guide to tricuspid valve repair

METHODS

A prospective analysis was performed on 50 patients (pts) with rheumatic mitral disease and associate secondary tricuspid insufficiency who underwent mitral valve replacement from January 1995 to December 1998. Surgical indication to tricuspid annuloplasty was considered in patients with echocardiographic tricuspid annulus diameter > 21 mm/m2, regardless semiquantitative evaluation of tricuspid insufficiency. De Vega annuloplasty was performed in 33 out of 50 patients.

RESULTS

Hospital mortality was 2.0% (CL 0.3-3.6). The follow up of the discharged patients ranged from 3 to 48 months (mean 25 +/- 15.9). Three late deaths occurred (6.1% CL 2.8-9.2). Forty-two patients out of the 46 followed up (91.3% CL 84.9-93.8) were in I or II NYHA class. In eight patients (16.3% of discharged patients) the obtained result has been considered as 'negative late results': persisting moderate (three cases) or moderate-severe (five cases) TrI, together with congestive heart failure requiring a furosemide intake of > 25 mg/day. No patients had severe TrI at follow up. The statistics analysis demonstrated the 'preoperative fraction shortening of the tricuspid annulus' (P = 0.038) as factor predictive of late negative result. The incidence of late negative result was 57.1% among patients with fractional shortening lower than 25% and 0% among those patients with fractional shortening greater than 25% (P = 0.0001).

CONCLUSIONS

The choice to treat the tricuspid insufficiency according to indexed tricuspid annulus dimension (> 21 mm/m2) has been effective in terms of clinical efficacy and of late functional result. Fractional shortening of the tricuspid annulus, expression of right ventricular cardiomyopathy in patients with poorest prognosis, affects the postoperative evolution of tricuspid insufficiency.

G20210A prothrombin gene polymorphism and prothrombin activity in subjects with or without angiographically documented coronary artery disease

BACKGROUND

G20210A prothrombin mutation has been associated with high prothrombin levels and an increased risk of venous thrombosis. The role of this common polymorphism, as well as that of prothrombin levels, in determining the risk of arterial disease is still somewhat controversial.

METHODS AND RESULTS

We determined the prevalence of the G20210A mutation and prothrombin activity in 660 individuals, of whom 436 had angiographically documented severe coronary artery disease (CAD patients) and 224 had normal coronary angiography (CAD-free control subjects). Heterozygosity for the 20210A allele was found in 5.3% of the CAD patients versus 3.1% of the CAD-free subjects (P=0.21). Similarly, no statistically significant difference was found between CAD patients with or without previous myocardial infarction (4.5% versus 5.3%, respectively; P=0.73). The genotype-phenotype correlation study showed a significant influence of the 20210A allele on prothrombin activity, with higher levels in carriers compared with noncarriers (153.2% versus 122.2%, respectively; P<0.001). Prothrombin activity was significantly higher in CAD patients than in CAD-free subjects (132.8% versus 123.3%, respectively; P<0.005). By multiple logistic regression, prothrombin activity in the upper tertile of the control distribution was significantly associated with CAD compared with prothrombin activity in the lower tertile (adjusted odds ratio 1.86, 95% CI 1.01 to 3.4).

CONCLUSIONS

In a population with a clear-cut definition of the phenotype, the G20210A prothrombin mutation was not significantly associated, per se, with either angiographically documented CAD or myocardial infarction, whereas it significantly influenced prothrombin activity. In our population, high prothrombin activity itself was independently associated with CAD but not with the presence or absence of previous myocardial infarction.

The beta-amyloid precursor protein APP is tyrosine-phosphorylated in cells expressing a constitutively active form of the Abl protoncogene

The cytosolic domain of the beta-amyloid precursor protein APP interacts with three PTB (phosphotyrosine binding domain)-containing adaptor proteins, Fe65, X11, and mDab1. Through these adaptors, other molecules can be recruited at the cytodomain of APP; one of them is Mena, that binds to the WW domain (a protein module with two conserved tryptophans) of Fe65. The enabled and disabled genes of Drosophila, homologues of the mammalian Mena and mDab1 genes, respectively, are genetic modulators of the phenotype observed in flies null for the Abl tyrosine kinase gene. The involvement of Mena and mDab1 in the APP-centered protein-protein interaction network suggests the possibility that Abl plays a role in APP biology. We show that Fe65, through its WW domain, binds in vitro and in vivo the active form of Abl. Furthermore, in cells expressing the active form of Abl, APP is tyrosine-phosphorylated. Phosphopeptide analysis and site-directed mutagenesis support the hypothesis that Tyr(682) of APP(695) is the target of this phosphorylation. Co-immunoprecipitation experiments demonstrate that active Abl and tyrosine-phosphorylated APP also form a stable complex, which could result from the interaction of the pYENP motif of the APP cytodomain with the SH2 domain of Abl. These results suggest that Abl, Mena, and mDab1 are involved in a common molecular machinery and that APP can play a role in tyrosine kinase-mediated signaling.

[Left monoventricular assistance with DeBakey VAD continuous flow pump: initial clinical Italian experience]

BACKGROUND

The shortage of heart donors causes a rise in mortality among candidates for cardiac transplantation and increases the waiting list. Consequently mechanical circulatory support for bridge to transplant is now a standard clinical procedure utilized in the most representative cardiac surgery centers. Recently, continuous-axial-flow pumps have been introduced in the clinical practice and have led to new perspectives.

METHODS

Four patients suffering from end-stage heart failure were implanted with a DeBakey ventricular assist device (VAD) continuous-flow pump as a bridge to heart transplant. The DeBakey VAD is smaller than the pulsatile devices commonly employed, the pump is totally implantable and is connected to a small controller and two batteries by a transcutaneous drive line.

RESULTS

One patient died of multiorgan failure during assistance; 3 patients were fully rehabilitated and were successfully transplanted after 55, 42 and 141 days respectively. In the early postoperative period the mean pump flow was 4.27 +/- 0.55 l/min, after 1 week of assistance the flow rose to 5.32 +/- 0.57 l/min and then progressively increased to 5.83 +/- 0.57 l/min.

CONCLUSIONS

This experience demonstrated the possibility of continuous-flow left ventricular support with the DeBakey VAD for mid-term mechanical ventricular assistance. This pump presents new interesting aspects and opens new perspectives for the future of left ventricular mechanical assistance. Increasing experience will define the role of this device in the scenario of heart failure.

Modulation of oncogenic DBL activity by phosphoinositol phosphate binding to pleckstrin homology domain

The Dbl family guanine nucleotide exchange factors (GEFs) contain a region of sequence similarity consisting of a catalytic Dbl homology (DH) domain in tandem with a pleckstrin homology (PH) domain. PH domains are involved in the regulated targeting of signaling molecules to plasma membranes by protein-protein and/or protein-lipid interactions. Here we show that Dbl PH domain binding to phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4,5-triphosphate results in the inhibition of Dbl GEF activity on Rho family GTPase Cdc42. Phosphatidylinositol 4,5-bisphosphate binding to the PH domain significantly inhibits the Cdc42 interactive activity of the DH domain suggesting that the DH domain is subjected to the PH domain modulation under the influence of phosphoinositides (PIPs). We generated Dbl mutants unable to interact with PIPs. These mutants retained GEF activity on Cdc42 in the presence of PIPs and showed a markedly enhanced activating potential for both Cdc42 and RhoA in vivo while displaying decreased cellular transforming activity. Immunofluorescence analysis of NIH3T3 transfectants revealed that whereas the PH domain localizes to actin stress fibers and plasma membrane, the PH mutants are no longer detectable on the plasma membrane. These results suggest that modulation of PIPs in both the GEF catalytic activity and the targeting to plasma membrane determines the outcome of the biologic activity of Dbl.

Homozygosity for angiotensinogen 235T variant increases the risk of myocardial infarction in patients with multi-vessel coronary artery disease

OBJECTIVE

Molecular variants of the angiotensinogen (AGT) and the angiotensin II type 1 receptor (ATR) genes have been associated with the risk of coronary artery disease (CAD) and myocardial infarction (MI), but data so far available are conflicting. The primary object of the paper is to verify this possible association by a rigorous, angiographically controlled study in a large sample of patients with or without multi-vessel CAD.

DESIGN

We designed a large case-control study in Italian patients candidates for coronary artery bypass grafting, with angiographically documented multi-vessel CAD, compared to subjects with angiographically documented normal coronary arteries.

METHODS AND RESULTS

AGT M235T and ATR A1166C gene polymorphisms were analysed in 699 subjects; 454 patients were candidates for coronary artery bypass grafting, having angiographically documented (mainly multi-vessel) CAD. An appropriate documentation of previous MI was obtained from 404/454 (89%, 247 with and 157 without MI). Subjects (n = 245) with angiographically documented normal coronary arteries, were included as control group (CAD-free group). CAD patients had a substantial burden of conventional risk factors as compared with controls free of coronary atherosclerosis. Age, gender, smoking habit and number of stenosed vessels were the only differences between patients with or without previous myocardial infarction, who were similarly exposed to the other conventional risk factors (including hypertension). AGT M235T and ATR A1166C allele and genotype frequencies were similar between CAD and CAD-free patients. In the CAD group, AGT 235T allele was found more frequently in subjects with a previous myocardial infarction (0.494 versus 0.414; P < or = 0.05). By logistic regression, homozygosity for AGT 235T variant appeared to confer 1.9-fold increased risk for MI in both the univariate and the multivariate (adjusted for age, gender, smoking habit and number of stenosed vessels) model.

CONCLUSIONS

AGT 235 T homozygous patients with multivessel CAD have an increased risk of myocardial infarction as compared with subjects with clinically similar phenotype but different genotype.

Amino-terminal modification and tyrosine phosphorylation of [corrected] carboxy-terminal fragments of the amyloid precursor protein in Alzheimer's disease and Down's syndrome brain

The carboxy-terminal fragments (CTFs) of the amyloid precursor protein (APP) are considered beta-amyloid (Abeta) precursors as well as molecular species possibly amyloidogenic and neurotoxic by [corrected] in vitro or in animal models. The CTF's role in the pathogenesis of Alzheimer's disease (AD) is however relatively unexplored in human brain. In this study, we analyzed brain extracted CTFs in subjects with AD, non-AD control, and Down's syndrome (DS) cases. Our data indicate that: (i) In fetal DS subjects CTFs levels are increased in comparison to age-matched control, suggesting that the enhanced CTFs formation is important for the early occurrence of plaques deposition in DS. No significant difference in CTFs level [corrected] between AD and age-matched control cases. (ii) CTFs modified at their N-terminus are the direct precursors of similarly N-terminally modified Abeta peptides, which constitute the most abundant species in AD and DS plaques. This observation suggests that N-truncated Abeta peptides are formed directly at beta-secretase level and not through a progressive proteolysis of full-length Abeta1-40/42. (iii) Among the differently cleaved CTFs, only the 22- and 12.5-kDa CTF polypeptides are tyrosine phosphorylated in both AD and control brain while the full-length APP and the CTFs migrating below the 12.5-kDa marker are not phosphorylated, suggesting that APP and CTFs may be involved in different pathways depending on their length and sequences. This study provides evidence that CTFs constitute in human brain a molecular species directly involved in AD pathogenesis and in the development of the AD-like pathology in DS subjects.

Serum cytokine levels and antibody response to influenza vaccine in the elderly

Cytokines play critical roles in regulating the antibody response to vaccines. We sought to understand the role of endogenous cytokines in the determination of antibody production in the elderly, a group of subjects known to have a lower response rate to vaccination. We found that in a healthy elderly group, only 52% of whom responded to the influenza vaccine, endogenous levels of interleukin 6 (IL-6), IL-10 and gamma interferon (IFNgamma) did not differ statistically significantly between responders and non-responders (responders: n = 27, IL-6 = 293 +/- 101 pg/ml, IL-10 = 882 +/- 240 pg/ml; nonresponders: n = 26, IL-6 = 223 +/- 71 pg/ml, P = 0.57, IL-10 = 445 +/- 148 pg/ml, mean +/- SE, P = 0.14, respectively, and undetectable IFNgamma). Serum levels of these three cytokines were not changed significantly four weeks after vaccination (P < 0.05 for IL-6 and P < 0.01 for IL-10). In addition, there were also no age-dependent differences in serum IL-6 and IL-10 levels.

Growth hormone replacement therapy in children with medulloblastoma: use and effect on tumor control

PURPOSE

Progress has been made in the treatment of medulloblastoma, the most common childhood malignant brain tumor: However, many long-term survivors will have posttherapy growth hormone insufficiency with resultant linear growth retardation. Growth hormone replacement therapy (GHRT) may significantly improve growth, but there is often reluctance to initiate GHRT because of concerns of an increased likelihood of tumor relapse.

PATIENTS AND METHODS

This study retrospectively reviewed the use of GHRT for survivors of medulloblastoma in 11 neuro-oncology centers in North America who received initial treatment for disease between 1980 and 1993 to determine its impact on disease control. A Landmark analysis was used to evaluate the relative risk of relapse in surviving patients.

RESULTS

Five hundred forty-five consecutive patients less than 15 years of age at diagnosis were identified. Six-year progression-free survival (mean +/- SD) was 40% +/- 5% in children less than 3 years of age at diagnosis compared with 59% +/- 3% for older patients. Older patients with total or near-total resections (P = .003) and localized disease at diagnosis (P < .0001) had the highest likelihood of survival. One hundred seventy patients (33% +/- 3% of the cohort) received GHRT. GHRT use varied widely among institutions, ranging from 5% to 73%. GHRT was begun a mean of 3.9 years after diagnosis, later in children younger than 3 years at diagnosis (5.4 years). By Landmark analyses, for those surviving 2, 3, and 5 years after diagnosis, there was no evidence that GHRT increased the rate of disease relapse.

CONCLUSION

This large retrospective review demonstrates that GHRT is underutilized in survivors of medulloblastoma and is used relatively late in the course of the illness. GHRT is not associated with an increased likelihood of disease relapse.

Resistance to multiple steroids in two sisters

A 14-year-old Native American girl from the Iroquois Nation was referred as a potential patient with the syndrome of Apparent Mineralocorticoid Excess. Instead, her evaluation revealed resistance to glucocorticoids, mineralocorticoids, and androgens. She lacked Cushingoid features in spite of significantly high cortisol levels. Menstruation was regular and there was no clinical evidence of masculinization despite high serum androgen levels in the male range. The patient's sister had similar clinical features. Partial resistance to exogenous glucocorticoid and mineralocorticoid administration was well demonstrated in both patients. It is proposed that these patients represent the first cases of partial resistance to multiple steroids, possibly owing to a coactivator defect.

Generation of an apoptotic intracellular peptide by gamma-secretase cleavage of Alzheimer's amyloid beta protein precursor

The amyloid beta protein precursor (AbetaPP) is sequentially processed by beta- and gamma-secretases to generate the Abeta peptide. The biochemical path leading to Abeta formation has been extensively studied since extracellular aggregates of amyloidogenic forms of Abeta peptide (Abeta42) are considered the culprit of Alzheimer's disease. Aside from its pathological relevance, the biological role of AbetaPP proteolysis is unknown. Although never previously described, cleavage of AbetaPP by gamma-secretase should release, together with Abeta, a COOH-terminal AbetaPP Intracellular Domain, herein termed AID. We have now identified AID-like peptides in brain tissue of normal control and patients with sporadic Alzheimer's disease and demonstrate that AID acts as a positive regulator of apoptosis. Thus, overproduction of AID may add to the toxic effect of Abeta42 aggregates and further accelerate neurodegeneration.