Impact of secondary mitral valve chordal cutting on valve geometry in obstructive hypertrophic cardiomyopathy with marked septal hypertrophy

AIMS

In patients with obstructive hypertrophic cardiomyopathy (HCM) and mild septal thickness undergoing myectomy, resecting fibrotic anterior mitral leaflet (AML) secondary chordae moves the mitral valve (MV) away from the outflow tract and ejection flow, reducing the need for a deep septal excision. Aim of the present study was to assess whether chordal resection has similarly favourable effects in patients with important hypertrophy, who represent the majority of patients with obstructive HCM.

METHODS AND RESULTS

The MV position in the ventricular cavity, assessed from echocardiography as AML-annulus ratio, was compared before and after chordal resection in 150 consecutive HCM patients with important (≥20 mm) and 62 with mild (≤19 mm) septal thickness undergoing myectomy. Preoperatively, MV position was displaced towards the septum to a similar extent in both groups. Postoperatively, AML-annulus ratio increased of an equal degree in both groups, from 0.43 ± 0.05 to 0.55 ± 0.06 (P < 0.001) a 28% increase, and from 0.43 ± 0.06 to 0.55 ± 0.06 (P < 0.001) a 26% increase, respectively, indicating a similar MV shift away from the outflow tract. When AML-annulus ratio was compared in the study cohort and 124 normal subjects, MV position was within normal range in <4% of patients preoperatively and normalized in >50% postoperatively.

CONCLUSIONS

In obstructive HCM, displacement of the MV apparatus into the outflow tract interferes with the ejection flow. Resection of fibrotic secondary chordae moves the MV apparatus away from the outflow tract and enlarges the outflow area independently of septal thickness, facilitating septal myectomy by reducing the need for a deep muscular excision.

Surgical Single Stage Treatment for Obstructive Hypertrophic Cardiomyopathy and Aortic Arch Aneurysm

Coexistence of obstructive hypertrophic cardiomyopathy and severe aortic pathology is extremely rare; nonetheless, the association between these two diseases is fascinating. Here we present a unique case report of a patient with obstructive hypertrophic cardiomyopathy and aortic arch aneurysm treated by a single surgical procedure.

Systematic cutting of selected secondary mitral valve chordae, in association with a shallow myectomy, in obstructive hypertrophic cardiomyopathy:impact on mitral valve function and patient management

Introduction

Few centers worldwide have large experience with performing an extended septal myectomy in patients with obstructive hypertrophic cardiomyopathy (HCM). Therefore, many HCM patients eligible for surgical relief of left ventricular (LV) outflow gradient do not have access to treatment. In a previous study, cutting fibrotic anterior mitral leaflet secondary chordae, in association with only a shallow myectomy, proved highly effective in moving the mitral valve (MV) apparatus away from the LV outflow tract and relieving the outflow gradient in our HCM patients with mild hypertrophy (&lt;19 mm), a surgical approach that simplifies the operation.

Purpose

To assess whether chordal cutting is equally effective in improving MV geometry and relieving LV outflow gradient and heart failure symptoms in HCM patients with more marked hypertrophy.

Methods

Surgical outcome and MV geometry and function were assessed in 226 consecutive HCM patients who underwent systematic cutting of fibrotic anterior mitral leaflet secondary chordae, in association with a shallow myectomy and independently of magnitude of septal thickness, at our center from January 2015 to December 2018.

Results

Of 226 study patients, 1 (0.4%) died perioperatively. None had iatrogenic septal defect. Postoperatively, LV outflow gradient at rest decreased from 70±36 to 10±2 mmHg (P&lt;0.001). In the 77 patients in whom data on the outflow gradient provoked with physiologic maneuvers after surgery were available, the provocable gradient was 16±10 mmHg. NYHA functional class improved significantly (P&lt;0.001), with the number of patients in class III-IV decreasing from 178 (79%) to 2 (0.9%). No patient had residual severe MV regurgitation and only 4 (1.7%) had moderate-to-severe regurgitation. Quality of the echocardiogram allowed assessment of MV geometry in 212 (94%) patients. In the 62 patients with mild hypertrophy, anterior leaflet-annulus ratio increased 27% postoperatively, from 0.43+0.06 to 0.55+0.06 and MV tenting area decreased 34% from 2.9+0.6 to 1.9+0.4 cm2 (P&lt;0.001), indicating repositioning of MV coaptation away from the outflow tract (with increased outflow tract dimension). Similarly, in 150 patients with marked hypertrophy, anterior leaflet-annulus ratio increased 27% from 0.43+0.05 to 0.55+0.06 and tenting area decreased 28% from 2.9+0.6 to 2.1+0.4 cm2 (P&lt;0.001).

Conclusions

Our results show that cutting fibrotic anterior mitral leaflet secondary chordae, by moving the MV apparatus away from the LV outflow tract and independently of the magnitude of septal hypertrophy, contributes to improve the results of septal myectomy and reduces the need for a deep septal excision (and associated risk of iatrogenic septal defect) in patients with obstructive HCM. Therefore, chordal cutting could make the myectomy operation more accessible to surgeons, increasing the availability of surgical treatment for HCM patients eligible for invasive abolition of LV outflow obstruction.

Funding Acknowledgement

Type of funding source: None

Cardioprotection of PLGA/gelatine cardiac patches functionalised with adenosine in a large animal model of ischaemia and reperfusion injury: A feasibility study

The protection from ischaemia‐reperfusion‐associated myocardial infarction worsening remains a big challenge. We produced a bioartificial 3D cardiac patch with cardioinductive properties on stem cells. Its multilayer structure was functionalised with clinically relevant doses of adenosine. We report here the first study on the potential of these cardiac patches in the controlled delivery of adenosine into the in vivo ischaemic‐reperfused pig heart. A Fourier transform infrared chemical imaging approach allowed us to perform a characterisation, complementary to the histological and biochemical analyses on myocardial samples after in vivo patch implantation, increasing the number of investigations and results on the restricted number of pigs (n = 4) employed in this feasibility step. In vitro tests suggested that adenosine was completely released by a functionalised patch, a data that was confirmed in vivo after 24 hr from patch implantation. Moreover, the adenosine‐loaded patch enabled a targeted delivery of the drug to the ischaemic‐reperfused area of the heart, as highlighted by the activation of the pro‐survival signalling reperfusion injury salvage kinases pathway. At 3 months, though limited to one animal, the used methods provided a picture of a tissue in dynamic conditions, associated to the biosynthesis of new collagen and to a non‐fibrotic outcome of the healing process underway. The synergistic effect between the functionalised 3D cardiac patch and adenosine cardioprotection might represent a promising innovation in the treatment of reperfusion injury. As this is a feasibility study, the clinical implications of our findings will require further in vivo investigation on larger numbers of ischaemic‐reperfused pig hearts.

Role of Preoperative Cardiovascular Magnetic Resonance in Planning Ventricular Septal Myectomy in Patients With Obstructive Hypertrophic Cardiomyopathy

In obstructive hypertrophic cardiomyopathy (HC), extreme heterogeneity of septal morphology makes septal myectomy particularly challenging. Although cardiovascular magnetic resonance (CMR) reconstructs ventricular anatomy with high spatial resolution, CMR is not used systematically to plan preoperatively septal myectomy. In this study, we report our results with using CMR to plan the extent of septal excision in 112 consecutive HC patients who subsequently underwent myectomy. Depth and length of the myectomy planned at CMR were compared with those of the septal muscle excised in a single piece in all patients. Anterior septum maximal thickness at CMR was 22 ± 5 mm and excised muscle thickness 9 ± 3 mm. Planned myectomy length was 35 ± 11 mm (range 17 to 65) and excised muscle length 38 ± 10 mm (range 10 to 70), indicating extension of septal resection to mid-cavity. Thickness and length of the planned myectomy showed a significant correlation with the excised muscle (R² = 0.345; p <0.001; and R² = 0.358; p <0.001, respectively). Deep septal crypts were identified at CMR in 12(11%) patients, preventing muscle excision from areas at increased risk of iatrogenic septal defect. Large aberrant muscle bundles that could decrease mid-cavity dimension were identified at CMR and excised in 26(23%) patients. In the 55 patients with postoperative CMR, qualitative comparison of pre and postoperative ventricular morphology showed a smooth and apically extended myectomy. In conclusion, CMR planning of septal myectomy provided high resolution images of septal morphology and allowed us to perform a standardized and apically extended septal excision that was associated with favorable outcome. Our novel approach could make myectomy more accessible to cardiovascular surgeons.

Emx2 is a dose-dependent negative regulator of Sox2 telencephalic enhancers

The transcription factor Sox2 is essential for neural stem cells (NSC) maintenance in the hippocampus and in vitro. The transcription factor Emx2 is also critical for hippocampal development and NSC self-renewal. Searching for ‘modifier’ genes affecting the Sox2 deficiency phenotype in mouse, we observed that loss of one Emx2 allele substantially increased the telencephalic β-geo (LacZ) expression of a transgene driven by the 5′ or 3′ Sox2 enhancer. Reciprocally, Emx2 overexpression in NSC cultures inhibited the activity of the same transgene. In vivo, loss of one Emx2 allele increased Sox2 levels in the medial telencephalic wall, including the hippocampal primordium. In hypomorphic Sox2 mutants, retaining a single ‘weak’ Sox2 allele, Emx2 deficiency substantially rescued hippocampal radial glia stem cells and neurogenesis, indicating that Emx2 functionally interacts with Sox2 at the stem cell level. Electrophoresis mobility shift assays and transfection indicated that Emx2 represses the activities of both Sox2 enhancers. Emx2 bound to overlapping Emx2/POU-binding sites, preventing binding of the POU transcriptional activator Brn2. Additionally, Emx2 directly interacted with Brn2 without binding to DNA. These data imply that Emx2 may perform part of its functions by negatively modulating Sox2 in specific brain areas, thus controlling important aspects of NSC function in development.

Pandemic influenza A/H1N1 virus in a swine farm house in Sicily, Italy

This report describes a pandemic A/H1N1 (H1N1 pdm) virus outbreak occurred in December, 2009 in a swine farm used as research facility (Istituto Mediterraneo Trapianti e Terapie ad Alta Specializzazione) for preclinical studies, located in Sicily, Italy. All the 13 pigs of the farm, showed cough, fever, inappetence and weakness. At the same time, an unvaccinated worker of the stabling showed influenza-like symptoms. RNAv extracted from two swabs collected from infected pigs resulted positive by Real Time RT-PCR for Influenza A virus. Furthermore, after growth on embryonated eggs, viral isolates were identified by Real Time RT-PCR specific for H1N1 pdm virus and characterized antigenically. Sequencing of the whole genome was also performed. All sera taken from animals and from the worker were tested by a competitive influenza A ELISA and by the haemoagglutination inhibition test. Serological findings confirmed the circulation of influenza virus H1N1 pdm in pigs and the presence of specific antibodies against H1N1 pdm in human serum. The results of this study seem to support a H1N1 pdm transmission from man to animals showing the importance of serological and virological investigation to control the pig farms and the importance of close cooperation between the different authorities like veterinarian and human public.

Quantitative profiling of the pathological prion protein allotypes in bank voles by liquid chromatography-mass spectrometry

The conversion of the cellular prion protein (PrP(C)) into a misfolded isoform (PrP(TSE)) that accumulates in the brain of affected individuals is the key feature of transmissible spongiform encephalopaties (TSEs). Susceptibility to TSEs is influenced by polymorphisms of the prion gene suggesting that the presence of certain amino acid residues may facilitate the pathological conversion. In this work, we describe a quantitative, fast and reliable HPLC-MS method that allowed to demonstrate that in the brain of 109(Met/Ile) heterozygous bank voles infected with the mouse adapted scrapie strain 139A, there are comparable amounts of PrP(TSE) with methionine or isoleucine in position 109, suggesting that in this TSE model the two allotypes have similar rates of accumulation. This method can be easily adapted for the quantitative determination of PrP allotypes in the brain of other natural or experimental TSE models.

Substrate preference of Bifidobacterium adolescentis MB 239: compared growth on single and mixed carbohydrates

The utilization of mono-, di-, and oligosaccharides by Bifidobacterium adolescentis MB 239 was investigated. Raffinose, fructooligosaccharides (FOS), lactose, and the monomeric moieties glucose and fructose were used. To establish a hierarchy of sugars preference, the kinetics of growth and sugar consumption were determined on individual and mixed carbohydrates. On single carbon sources, higher specific growth rates and cell yields were attained on di- and oligosaccharides compared to monosaccharides. Analysis of the carbohydrates in steady-state chemostat cultures, growing at the same dilution rate on FOS, lactose, or raffinose, showed that monomeric units and hydrolysis products were present. In chemostat cultures on individual carbohydrates, B. adolescentis MB 239 simultaneously displayed alpha-galactosidase, beta-galactosidase, and beta-fructofuranosidase activities on all the sugars, including monosaccharides. Glycosyl hydrolytic activities were found in cytosol, cell surface, and growth medium. Batch experiments on mixtures of carbohydrates showed that they were co-metabolized by B. adolescentis MB 239, even if different disappearance kinetics were registered. When mono-, di-, and oligosaccharides were simultaneously present in the medium, no precedence for monosaccharides utilization was observed, and di- and oligosaccharides were consumed before their constitutive moieties.

Identification of the pathological prion protein allotypes in scrapie-infected heterozygous bank voles (Clethrionomys glareolus) by high-performance liquid chromatography-mass spectrometry

Cerebral formation of the pathological isoform of the prion protein (PrP) is a crucial molecular event in prion diseases. The bank vole (Clethrionomys glareolus) is a rodent species highly susceptible to natural scrapie. The PrP gene of bank vole is polymorphic (Met/Ile) at codon 109. Here we show that homozygous 109Met/Met voles have incubation times shorter than heterozygous 109Met/Ile voles after experimental challenge with three different scrapie isolates. An HPLC-MS/MS method was optimized and applied to investigate whether in heterozygous animals both PrP allotypes are able to undergo pathological conversion. The results demonstrate that both allotypes of the prion protein participate to pathological deposition.

Diagnosis and PrP genotype target of scrapie in clinically healthy sheep of Massese breed in the framework of a scrapie eradication programme

The application of a selective culling programme in two scrapie affected flocks of Massese breed sheep is described. The genetic susceptibility of this breed and the sensitivity of different diagnostic methods in the pre-clinical diagnosis of scrapie were also investigated. Overall, 2,068 clinically healthy sheep underwent PrP genotyping, providing the basis for selective culling. The prevalence of scrapie infection was investigated in susceptible sheep by two independent diagnostic methods. All the sheep older than 18 months (n = 620) were tested by Prionics Check Western rapid test on the obex, with a prevalence of infection of 3.9%. Furthermore, 385 sheep underwent immunohistochemistry (IHC) on retropharyngeal lymph node (RPLN), with a prevalence of infection of 5.2%. Overall, 32 sheep were diagnosed with pre-clinical scrapie. Of these, 31 were positive by Western blot on the spleen, 29 by IHC on the RPLN and tonsil, 28 by IHC on the obex, 24 by rapid test, and only 18 by IHC on the third eyelid. All the scrapie positive sheep were of the ARQ/ARQ, ARQ/AHQ or ARQ/VRQ genotypes. No significant differences in scrapie prevalence were observed among these genotypes. The estimated risk of the three targeted alleles was also similar, suggesting that in this breed the VRQ allele was not at higher risk for scrapie, compared to the ARQ and AHQ alleles.

Primer extension assay for prion protein genotype determination in sheep

Scrapie is a transmissible spongiform encephalopathy (TSE) which affects sheep and goats. TSEs are characterised by the conversion of the cellular prion protein (PrP(C)) into the pathological form PrP(Sc). The occurrence of scrapie in sheep is influenced by polymorphisms in the PrP gene; in particular, three codons (136, 154 and 171) are important in conditioning the susceptibility/resistance of sheep to the disease, with the Val/Val(136) Arg/Arg(154) Gln/Gln(171) genotype being the most susceptible and the Ala/Ala(136) Arg/Arg(154) Arg/Arg(171), the most resistant one. The latter genotype seems to confer, in sheep, resistance to the oral infection with bovine spongiform encephalopathy, as well. The selection of genetically resistant sheep populations represents the basis of the recent strategies against ovine TSE in the European Union (EU). Herein, we describe a rapid and simple method, based on the primer extension technique, for PrP genotype determination at codons 136, 154 and 171. Intra-laboratory validation of the method showed accuracy levels comparable to those of sequencing analysis. Such method could be used for both the application of the EU policies requiring PrP genotype analysis in all ovine TSE cases, and the large-scale genotyping claimed by the implementation of breeding programmes for genetic resistance to TSE in sheep.

Assessment of In-Line Near-Infrared Spectroscopy for Continuous Monitoring of Fermentation Processes

The application of NIR in-line to monitor and control fermentation processes was investigated. Determination of biomass, glucose, and lactic and acetic acids during fermentations of Staphylococcus xylosus ES13 was performed by an interactance fiber optic probe immersed into the culture broth and connected to a NIR instrument. Partial least squares regression (PLSR) calibration models of second derivative NIR spectra in the 700-1800 nm region gave satisfactory predictive models for all parameters of interest: biomass, glucose, and lactic and acetic acids. Batch, repeated batch, and continuous fermentations were monitored and automatically controlled by interfacing the NIR to the bioreactor control unit. The high frequency of data collection permitted an accurate study of the kinetics, supplying lots of data that describe the cultural broth composition and strengthen statistical analysis. Comparison of spectra collected throughout fermentation runs of S. xylosus ES13, Lactobacillus fermentum ES15, and Streptococcus thermophylus ES17 demonstrated the successful extension of a unique calibration model, developed for S. xylosus ES13, to other strains that were differently shaped but growing in the same medium and fermentation conditions. NIR in-line was so versatile as to measure several biochemical parameters of different bacteria by means of slightly adapted models, avoiding a separate calibration for each strain.

Progressive histiocytosis: description of a case of slow-course non-Langerhans cell histiocytosis

We describe the case of a 37-year-old male patient who in 1992 started developing a skin eruption characterized by dark red to red-yellow papulonodular lesions that showed no tendency to spontaneous resolution. Visceral organs were not involved and the lipid pattern was basically normal. Histological examination revealed an infiltrate in the mid and upper dermis mainly consisting of mononucleated and multinucleated histiocytes with an abundant eosinophilic cytoplasm and a ground glass appearance, admixed with numerous xanthomatized cells and Touton and foreign-body giant cells. Immunohistochemical studies showed positivity for CD68 and negativity for CD1a and S-100 protein, whereas at the electron microscopy level the only peculiar finding was the presence of many desmosome-like junctions. The authors believe this to be a borderline form between papular xanthoma and reticulohistiocytosis.

Near-infrared spectroscopy: a tool for monitoring submerged fermentation processes using an immersion optical-fiber probe

Near-infrared (NIR) spectroscopy has been developed as a noninvasive tool for the direct, real-time monitoring of glucose, lactic acid, acetic acid, and biomass in liquid cultures of microrganisms of the genera Lactobacillus and Staphylococcus. This was achieved employing a steam-sterilizable optical-fiber probe immersed in the culture (In-line Interactance System). Second-derivative spectra obtained were subjected to partial least-squares (PLS) regression and the results were used to build predictive models for each analyte of interest. Multivariate regression was carried out on two different sets of spectra, namely whole broth minus the spectral subtraction of water, and raw spectra. A comparison of the two models showed that the first cannot be properly applied to real-time monitoring, so this work suggests calibration based on non-difference spectra, demonstrating it to be sufficiently reliable to allow the selective determination of the analytes with satisfactory levels of prediction (standard error of prediction (SEP) < 10%). Direct interfacing of the NIR system to the bioreactor control system allowed the implementation of completely automated monitoring of different cultivation strategies (continuous, repeated batch). The validity of the in-line analyses carried out was found to depend crucially on maintaining constant hydrodynamic conditions of the stirred cultures because both gas flow and stirring speed variations were found to markedly influence the spectral signal.

Animal Transmissible Spongiform Encephalopathies and Genetics

The genotype of the host plays a crucial role in the pathogenesis of transmissible spongiform encephalopathies (TSEs). In this respect, the most important factor is represented by the gene of the prion protein (PrP). The present work summarizes the currently available knowledge on the genetic basis of TSEs focusing, in particular, on sheep scrapie. Interest in this disease has grown markedly following the discovery of bovine spongiform encephalopathy, both for scientific and health reasons. In Italy, specific research grants from the Ministry of Health and the National Research Council (CNR), together with cooperation between the Istituto Superiore di Sanità and the Istituti Zooprofilattici Sperimentali, have allowed us to study the PrP genotype and to investigate the genetic susceptibility to scrapie in the most important Italian sheep breeds, with special reference to Sarda, Comisana and Massese. The PrP genotype in relation to scrapie susceptibility was also studied in goats of Ionica breed.

PrP genotype in Sarda breed sheep and its relevance to scrapie. Brief report

Several PrP gene polymorphisms modulate sheep scrapie susceptibility. Recently, an increase of scrapie outbreaks has been reported in Italy. A vaccine containing sheep brain homogenate was used in most of the outbreaks. We investigated PrP gene polymorphisms in scrapie-affected and clinically healthy Sarda breed sheep from a flock exposed to the aforementioned vaccine, and in affected Sarda sheep from unexposed flocks. All affected animals were (Gln/Gln)171 homozygous. Moreover, we observed no variation for Ala136 and a new polymorphism (Lys to Asn) at codon 176. Our findings confirm the correlation between scrapie and (Gln/Gln)171 in breeds with no variation for Ala136.

Genomic organization, comparative analysis, and genetic polymorphisms of the bovine and ovine prion Doppel genes (PRND)

The doppel protein (Dpl) is a prion-like protein encoded by the gene PRND, which has been found downstream of the prion gene, PRNP, in human and mouse. This paper describes the isolation and structural organization of the bovine and ovine PRND genes, which are composed of two exons compared with the three of human and mouse. Intergenic distances between PRNP and PRND were covered by means of long-range PCR and found to be 16.8 and 20 kb, in cattle and sheep respectively. The 5' and 3' untranslated regions (UTR) were analyzed to identify transcription regulatory sequences and compared with those from the PRND and PRNP sequences published for other species. Three polymorphisms (R50H, N110H, and R132Q) were revealed in the cattle coding region; two synonymous substitutions (I12I, A26A) were found in sheep. None of the polymorphisms was significantly associated with either Bovine Spongiform Encephalopathy (BSE) in cattle or scrapie in sheep.

Intramural hematoma of the aorta: diagnosis and treatment

OBJECTIVE

Increasing use of modern high-resolution imaging techniques yields to describe very early stages of aortic pathology which, if left untreated, may lead to overt aortic dissection. One typical example is aortic intramural hematoma (IMH) with a limited number of cases described in the literature and uncertainties still existing about the most appropriate treatment. Purpose of our study is to report our experience in the evaluation and treatment of IMHs.

METHODS

From 1991 to 1999 175 patients were conveyed to our centre for aortic dissection; in nine of them diagnosis of acute IMH was performed.

RESULTS

Diagnosis was obtained by means of conventional CT scan of the chest. All the patients underwent surgery, one patient died (11%). At the follow-up (mean 31 months) eight patients were alive and well and did not require any other cardiac surgery.

CONCLUSIONS

The possibility to progress to overt aortic dissection may explain the need to an early diagnosis in the treatment of acute IMHs. Immediate surgical treatment is, in our experience, the preferred therapeutic option.

Mediastinal false aneurysm after thoracic aortic surgery

BACKGROUND

Postoperative mediastinal false aneurysm is associated with a substantial morbidity and mortality. Surgical treatment is mandatory, although the individual approach varies according to the type of pathologic process, infection status, and site of origin of the aneurysm.

METHODS

Between April 1993 and February 1999, we treated 10 patients, aged 25 to 73 years, with anastomotic mediastinal false aneurysm originating from the proximal thoracic aorta. Nine had undergone prior operations on the ascending aorta (7, type A dissection repair; 1, aortitis; 1, root abscess) with a Dacron conduit (n = 5) or valved conduit (n = 4). The last patient had undergone valve replacement for excavating aortic root sepsis. False aneurysms were detected from 2 to 70 months after the most recent operation. Three patients had positive tissue cultures. The surgical procedure was direct suture repair of the disrupted anastomosis in 5, root or ascending aortic replacement with an aortic homograft in 4, and Dacron graft interposition in 1. Hypothermic low-flow perfusion with or without circulatory arrest was used in all patients.

RESULTS

There was one hospital death caused by staphylococcal mediastinitis. A false aneurysm recurred after direct suture repair in 2 patients with underlying type A dissection or aortitis. This resulted in one late death. One patient experienced a neurologic event during removal of an infected vascular graft. All 8 surviving patients are alive and well after a mean follow-up of 2 years. Three patients with mycotic false aneurysms remain free from infection after aortic homograft replacement.

CONCLUSIONS

Mediastinal false aneurysms are surgically taxing. Low-flow hypothermic perfusion with or without circulatory arrest allows safe reentry. Radical surgery provides a satisfactory outcome in infected patients. Local repair of suture dehiscence in pathologic tissues may predispose to recurrence. We suspect that excessive use of formalin in gelatin-resorcin-formol glue may predispose to tissue necrosis.

A rapid and efficient method for the detection of point mutations of the human prion protein gene (PRNP) by direct sequencing

Creutzfeldt-Jakob disease (CJD) and related disorders occur in sporadic, acquired and inherited forms. In sporadic, iatrogenic and new variant CJD the polymorphic codon 129 of the prion protein gene (PRNP) plays an important role for the susceptibility to the disease and for the clinical and neuropathological manifestations. All the inherited forms of CJD and related disorders are linked to point or insert mutations of PRNP. The analysis of PRNP is therefore important for a correct classification of these disorders and for the identification of novel mutations. The aim of the present study is to describe a fast and easy to perform method for the direct sequencing of the PCR amplified PRNP open reading frame, by using M13 tailed primers which allow a direct and rapid method of sequencing. The goodness of this method is demonstrated in the analysis of three sporadic CJD patients with different genotypes at codon 129 and three inherited cases bearing different point mutations of PRNP: the Pro102Leu mutation linked to Gerstmann-Sträussler-Scheinker-syndrome, the Val210Ile mutation and a novel mutation at codon 211 (Gln211Glu) both associated to familial CJD.

Aortic root replacement with coronary button re-implantation: low risk and predictable outcome

OBJECTIVE

Cardiac morbidity in aortic root replacement often occurs through myocardial ischaemia. We analyzed a 10 year experience of all root replacement operations by one surgeon to determine the incidence of coronary complications and risk factors for early mortality.

METHODS

The study included 140 aortic root replacement patients (aged from 2 to 77 years; median 53 years) operated between 1988 and 1999. Thirty-four had Marfan's syndrome. Eleven had root infection requiring homograft replacement. Nineteen were reoperations (14%). Concomitant procedures were arch replacement (16), mitral replacement (five), and coronary bypass (22). Mobilization and reimplantation of the coronary ostia was performed in 139 patients. We performed the distal graft anastomosis before right coronary reimplantation.

RESULTS

There were eight hospital deaths (5.7%). Risk factors for hospital mortality were: preoperative NYHA class IV, shock, LVEF < or =30%, acute dissection, concomitant mitral valve replacement, pump time > or = 60 min, reentry for bleeding, and postoperative renal failure. Neither myocardial ischaemia nor right ventricular dysfunction contribute to mortality. There were 18 late deaths with an actuarial survival of 79% at 5 years. There were no late coronary false aneurysms.

CONCLUSIONS

Button reimplantation with the sequence described is predictable and safe. Wrap-around is unnecessary. Coronary aneurysms have been eliminated.

Enhanced production of L-(+)-lactic acid in chemostat by Lactobacillus casei DSM 20011 using ion-exchange resins and cross-flow filtration in a fully automated pilot plant controlled via NIR

Due to the lack of suitable in-process sensors, on-line monitoring of fermentation processes is restricted almost exclusively to the measurement of physical parameters only indirectly related to key process variables, i.e., substrate, product, and biomass concentration. This obstacle can be overcome by near infrared (NIR) spectroscopy, which allows not only real-time process monitoring, but also automated process control, provided that NIR-generated information is fed to a suitable computerized bioreactor control system. Once the relevant calibrations have been obtained, substrate, biomass and product concentration can be evaluated on-line and used by the bioreactor control system to manage the fermentation. In this work, an NIR-based control system allowed the full automation of a small-scale pilot plant for lactic acid production and provided an excellent tool for process optimization. The growth-inhibiting effect of lactic acid present in the culture broth is enhanced when the growth-limiting substrate, glucose, is also present at relatively high concentrations. Both combined factors can result in a severe reduction of the performance of the lactate production process. A dedicated software enabling on-line NIR data acquisition and reduction, and automated process management through feed addition, culture removal and/or product recovery by microfiltration was developed in order to allow the implementation of continuous fermentation processes with recycling of culture medium and cell recycling. Both operation modes were tested at different dilution rates and the respective cultivation parameters observed were compared with those obtained in a conventional continuous fermentation. Steady states were obtained in both modes with high performance on lactate production. The highest lactate volumetric productivity, 138 g L(-1) h(-1), was obtained in continuous fermentation with cell recycling.

The Sorin stentless pericardial valve: implant technique and hemodynamic profile

Stentless porcine xenografts have had significant impact on the hemodynamics, left ventricular remodeling, and survival after aortic valve replacement. We sought to establish a similar trend for the stentless pericardial valve. In a consecutive unselected series of 54 patients over 65 years of age, we refined the implant method for the stentless aortic pericardial valve and defined the pitfalls. We used a detailed echocardiographic study designed by the Food and Drug Administration to define the early valve hemodynamics and changes in left ventricular function. The valve is user friendly. With an easily reproducible implant technique, very low mean (7.1+/-3.4 mm Hg) and peak (13.6+/-6.3 mm Hg) transvalvular gradients were obtained, which did not decline significantly with time. Left ventricular mass index declined accordingly over 6 months (147+/-49 g/m2 to 125+/-39 g/m2). Mild aortic regurgitation, which did not influence left ventricular mass regression, occurred (26%) predominantly in the first half of the series because of size discrepancy between the annulus and a dilated sinotubular junction. Aortic regurgitation was virtually eliminated by tailoring of the sinotubular junction in the noncoronary sinus. The stentless pericardial valve provides excellent early hemodynamics and is a realistic alternative to the stentless porcine xenograft or aortic homograft for subcoronary aortic valve replacement in elderly patients. Valve durability is yet to be defined.

Direct repair of giant right coronary aneurysm

We describe a novel method for surgical repair of giant right coronary aneurysm. Instead of aneurysm ligation and coronary bypass we mobilized the inflow and outflow and performed end-to-end anastomosis. This preserved the native vessel. Restudy in both patients confirmed the effectiveness of this technique.

Coronary reimplantation in aortic root replacement: a method to avoid tension

We describe a technique to relieve tension on the reimplanted right coronary button during aortic root replacement. A hood is fashioned from autogenous aorta or pericardium to provide a funnel inflow to the coronary ostium. The technique can be used either electively or as a rescue maneuver in the event of right ventricular ischemia.

Arch and descending aortic aneurysms: influence of perfusion technique on neurological outcome

OBJECTIVE

Although cannulation of the femoral artery is used routinely for thoracic aortic operations with hypothermic circulatory arrest, retrograde perfusion through the descending aorta carries the risk of cerebral malperfusion or embolism. We have, therefore, routinely used a central cannulation technique for distal arch and descending aortic operations since 1995. In this study, we compared neurological outcome in consecutive patients undergoing femoral versus ascending aortic perfusion for these aneurysms.

METHODS

Between 1987 and 1998, 61 patients underwent aortic resection with circulatory arrest, but without retrograde cerebral perfusion, for lesions of the aortic arch and descending aorta. Thirty-one patients had fusiform true aneurysms, 19 had aortic dissection and 11 had extensive saccular or false aneurysms. Thirty-two patients (52%) were perfused via the femoral artery (group A), and 29 patients (48%) from the ascending aorta (group B). Operative mortality and morbidity, and neurological outcome, were reviewed.

RESULTS

There were no differences between the groups in mean age, pathology, abdominal and peripheral vascular disease, net perfusion time, or circulatory arrest time. There were four hospital deaths (three in group A and one in group B; P = 0.61), including one neurological death in group A, group A suffered a higher incidence of neurological events (nine patients: 28%) than group B (two patients: 7%; P = 0.03). Temporary focal neurological deficits occurred in both groups (two patients in group A, 6% and two patients in group B, 7%; P > 0.99), but permanent injury occurred exclusively in group A (seven patients: four with monoplegia, one with hemiplegia, and two with diffuse cerebral injury with one death; P = 0.01).

CONCLUSIONS

Anterograde perfusion using a proximal aortic cannula provides a low risk of cerebral embolism and allows extensive aortic resection with low morbidity.

Apoptosis and growth inhibition of squamous carcinoma cells treated with interferon-alpha, IFN-beta and retinoic acid are associated with induction of the cyclin-dependent kinase inhibitor p21

Recent studies have revealed promising leads on the potential of interferons (IFNs) in combination with retinoids in solid tumor therapy. The role of IFN-alpha and retinoic acid (RA) in cervical cancer is currently under active study. Because preclinical and clinical data on IFN-beta in combination with retinoids show promising results against breast carcinoma, we analysed the anti-proliferative effect of human recombinant IFN-beta alone or in combination with all-trans RA on two human squamous cervical carcinoma cell (SCC) lines (ME180 and SiHa). The two cell lines differ in their sensitivity to the anti-proliferative effects of the different agents and their combination: i) both cell lines were more responsive to IFN-beta than to IFN-alpha2b; ii) combined treatment with RA increases the growth inhibitory effect of the single agents in ME180, but not in SiHa; iii) the antiproliferative effect correlates with the induction of apoptosis. We suggest as a possible mechanisms of action that interferon regulatory factor-1 (IRF-1), a transcription factor which belongs to the IFN machinery, and the cyclin-dependent kinase inhibitor (CDKi) p21 can be involved in cellular growth inhibition and in the induction of apoptosis. These results support the use of IFN-beta in further clinical investigation possibly in combination with retinoids.

Combined use of single and double-cross steel wires for closure of midline sternotomy

BACKGROUND

We describe an improved technique for sternal closure which is performed using combined single and double-cross steel wires. We made a mechanical study of these single and double-cross shapes considering the effects of applied transverse and longitudinal shearing forces.

METHODS

We used this technique in 80 patients who underwent coronary surgery with the use of bilateral internal mammary arteries.

RESULTS

Among them no major wound complications occurred, and in all cases a firm stabilization of the sternum was achieved.

CONCLUSIONS

We therefore consider this technique of sternal closure easy, safe and effective, also in patients considered at risk for sternal dehiscence.

Stentless xenograft repair of excavating aortic root sepsis

BACKGROUND

A variety of surgical techniques are used to manage a disintegrated aortic annulus in patients with endocarditis and excavating aortic root sepsis. Homograft root replacement is preferable in this setting but suitable homografts are restricted in availability and excision of the aortic root carries the risk of postoperative bleeding. As an alternative we used a stentless porcine xenograft root (Medtronic Freestyle valve) to manage this problem.

METHODS

Three male patients with active endocarditis presented with aortic root abscess and partial or complete aorto-left ventricular discontinuity. One had prosthetic valve endocarditis, and the abscess cavity entered the right atrium in another. The porcine aortic root was successfully implanted using the modified subcoronary technique providing a repair within the aortic root with proximal and distal suture lines that excluded the disintegrating tissues from the blood stream. All patients were treated with intravenous antibiotics for 6 weeks postoperatively and none suffered recurrent infection (follow-up > 6 months).

CONCLUSION

The stentless porcine aortic root implanted within the human aorta provides an additional surgical option for excavating aortic root sepsis.

[Heterotopic heart transplantation in the rat: an experimental method for evaluating myocardial protection]

This research represents the first part of a project finalized to prolong the ischemic time of the explanted heart. Our experimental model utilizes rat hearts heterotopically transplanted into the abdomen of a recipient: a denervated heart but perfused by blood as to permit a good evaluation of the reperfusion damage. We used 3 different types of cardioplegic solutions to achieve cardiac arrest: the first of the intracellular fluid type, the second of the extracellular type and the third one as a standard cardioplegic solution supplemented by Ca++ antagonist. Cold saline 4 degrees C was used as control. Histological patterns, birefringence index and intracellular content of high energy phosphates were evaluated. Specimens were taken after 1 hour of ischemic time and after 1 hour of reperfusion. Early results show that administration of cardioplegic solution maintains birefringence index and preserve high energy phosphates: among the 3 different types of solution the intracellular type seems to achieve better results although the number of experiments is too small to show any statistical significance. These data show that this model is appropriate to test cardioplegic solutions and their effectiveness.