Fluorescence in situ hybridization and microbial community profiling analysis of explanted cochlear implants

BACKGROUND

Cochlear implant (CI) infections affect a small, but significant number of patients. Unremitting infections can lead to explantation. Fluorescence in situ hybridization (FISH) and microbial community profiling (MCP) are methods of studying microbial environments of explanted devices that can provide information to reduce morbidity and costs of infected CIs.

AIMS/OBJECTIVES

To describe the results and clinical significance of bacterial analyses conducted on explanted CIs.

MATERIAL AND METHODS

Between 2013 and 2017, 12 explanted devices underwent microbiological analysis in addition to the manufacturer's device failure analysis. Patients' clinical history, infection status and outcome were reviewed and correlated with microbial analysis results.

RESULTS

From 2013 to 2017, 12 Cochlear™ devices from 11 patients underwent additional MCP or FISH analysis. Five devices were explanted due to suspected implant associated infection, and seven were explanted for other reasons. FISH analysis revealed biofilm presence on all infected devices, only partial correlation of cultures with biofilm composition and confirmation that biofilm formation occurs preferentially at particular device interfaces and geometries. MCP analysis presented challenges in data analysis inherent to its technique but correlated with cultures of infected devices and suggested a diverse microbial composition of explanted devices.

CONCLUSIONS AND SIGNIFICANCE

Microbial analysis of explanted devices can aid in further elucidating treatment approaches to infected CIs.

Evolution of biofilm-forming pathogenic bacteria in the presence of nanoparticles and antibiotic: adaptation phenomena and cross-resistance

Background

Treatment of bacterial biofilms are difficult and in many cases, expensive. Bacterial biofilms are naturally more resilient to antimicrobial agents than their free-living planktonic counterparts, rendering the community growth harder to control. The present work described the risks of long-term use of an important alternative antimicrobial, silver nanoparticles (NAg), for the first time, on the dominant mode of bacterial growth.

Results

NAg could inhibit the formation as well as eradicating an already grown biofilm of Pseudomonas aeruginosa, a pathogen notorious for its resilience to antibiotics. The biofilm-forming bacterium however, evolved a reduced sensitivity to the nanoparticle. Evidence suggests that survival is linked to the development of persister cells within the population. A similar adaptation was also seen upon prolonged exposures to ionic silver (Ag⁺). The persister population resumed normal growth after subsequent passage in the absence of silver, highlighting the potential risks of recurrent infections with long-term NAg (and Ag⁺) treatments of biofilm growth. The present study further observed a potential silver/antibiotic cross-resistance, whereby NAg (as well as Ag⁺) could not eradicate an already growing gentamicin-resistant P. aeruginosa biofilm. The phenomena is thought to result from the hindered biofilm penetration of the silver species. In contrast, both silver formulations inhibited biofilm formation of the resistant strain, presenting a promising avenue for the control of biofilm-forming antibiotic-resistant bacteria.

Conclusion

The findings signify the importance to study the nanoparticle adaptation phenomena in the biofilm mode of bacterial growth, which are apparently unique to those already reported with the planktonic growth counterparts. This work sets the foundation for future studies in other globally significant bacterial pathogens when present as biofilms. Scientifically based strategies for management of pathogenic growth is necessary, particularly in this era of increasing antibiotic resistance.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01027-8.

Device Design Modifications Informed by In Vitro Testing of Bacterial Attachment Reduce Infection Rates of Cochlear Implants in Clinical Practice

Recalcitrant chronic infections of implanted medical devices are often linked to the presence of biofilms. The prevention and treatment of medical device-associated infections is a major source of antibiotic use and driver of antimicrobial resistance globally. Lowering the incidence of infection in patients that receive implanted medical devices could therefore significantly improve antibiotic stewardship and reduce patient morbidity. Here we determined if modifying the design of an implantable medical device to reduce bacterial attachment, impacted the incidence of device-associated infections in clinical practice. Since the 1980s cochlear implants have provided long-term treatment of sensorineural hearing deficiency in hundreds of thousands of patients world-wide. Nonetheless, a relatively small number of devices are surgically explanted each year due to unresolvable infections. Features associated with the accumulation of bacteria on the Cochlear™ Nucleus® CI24RE™ model of cochlear implant devices were identified using both in vitro bacterial attachment assays and examination of explanted devices. Macro-scale design modifications that reduced bacterial attachment in vitro were incorporated into the design of the CI500™ and Profile™ series of Nucleus implant. Analyses of mandatory post-market vigilance data of 198,757 CI24RE and 123,084 CI500/Profile series implantation surgeries revealed that these design modifications correlated with significantly reduced infection rates. This study demonstrates that a design-centric approach aimed at mitigating bacterial attachment was a simple, and effective means of reducing infections associated with Cochlear Nucleus devices. This approach is likely to be applicable to improving the designs of other implantable medical devices to reduce device-associated infections.

Explosive cell lysis as a mechanism for the biogenesis of bacterial membrane vesicles and biofilms

Many bacteria produce extracellular and surface-associated components such as membrane vesicles (MVs), extracellular DNA and moonlighting cytosolic proteins for which the biogenesis and export pathways are not fully understood. Here we show that the explosive cell lysis of a sub-population of cells accounts for the liberation of cytosolic content in Pseudomonas aeruginosa biofilms. Super-resolution microscopy reveals that explosive cell lysis also produces shattered membrane fragments that rapidly form MVs. A prophage endolysin encoded within the R- and F-pyocin gene cluster is essential for explosive cell lysis. Endolysin-deficient mutants are defective in MV production and biofilm development, consistent with a crucial role in the biogenesis of MVs and liberation of extracellular DNA and other biofilm matrix components. Our findings reveal that explosive cell lysis, mediated through the activity of a cryptic prophage endolysin, acts as a mechanism for the production of bacterial MVs.

Combination of Silver Nanoparticles and Curcumin Nanoparticles for Enhanced Anti-biofilm Activities

Biofilm tolerance has become a serious clinical concern in the treatment of nosocomial pneumonia owing to the resistance to various antibiotics. There is an urgent need to develop alternative antimicrobial agents or combination drug therapies that are effective via different mechanisms. Silver nanoparticles (AgNPs) have been developed as an anti-biofilm agent for the treatment of infections associated with the use of mechanical ventilations, such as endotracheal intubation. Meanwhile curcumin, a phenolic plant extract, has displayed natural anti-biofilm properties through the inhibition of bacterial quorum sensing systems. The aim of this study was to investigate the possible synergistic/additive interactions of AgNPs and curcumin nanoparticles (Cur-NPs) against both Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) microorganisms. The combination of AgNPs and Cur-NPs (termed Cur-SNPs) at 100 μg/mL disrupted 50% of established bacterial biofilms (formed on microtiter plates). However, further increase in the concentration of Cur-SNPs failed to effectively eliminate the biofilms. To achieve the same effect, at least 500 μg/mL Cur-NP alone was needed. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) revealed that combination therapy (Cur-SNPs) was the most potent to eradicate preformed biofilm compared to monodrug therapy. These agents are also nontoxic to healthy human bronchial epithelial cells (BEAS2B).

Extracellular ATP inhibits twitching motility-mediated biofilm expansion by Pseudomonas aeruginosa

Background

Pseudomonas aeruginosa is an opportunistic pathogen that exploits damaged epithelia to cause infection. Type IV pili (tfp) are polarly located filamentous structures which are the major adhesins for attachment of P. aeruginosa to epithelial cells. The extension and retraction of tfp powers a mode of surface translocation termed twitching motility that is involved in biofilm development and also mediates the active expansion of biofilms across surfaces. Extracellular adenosine triphosphate (eATP) is a key “danger” signalling molecule that is released by damaged epithelial cells to alert the immune system to the potential presence of pathogens. As P. aeruginosa has a propensity for infecting damaged epithelial tissues we have explored the influence of eATP on tfp biogenesis and twitching motility-mediated biofilm expansion by P. aeruginosa.

Results

In this study we have found that eATP inhibits P. aeruginosa twitching motility-mediated expansion of interstitial biofilms at levels that are not inhibitory to growth. We have determined that eATP does not inhibit expression of the tfp major subunit, PilA, but reduces the levels of surface assembled tfp. We have also determined that the active twitching zone of expanding P. aeruginosa interstitial biofilms contain large quantities of eATP which may serve as a signalling molecule to co-ordinate cell movements in the expanding biofilm. The inhibition of twitching motility-mediated interstitial biofilm expansion requires eATP hydrolysis and does not appear to be mediated by the Chp chemosensory system.

Conclusions

Endogenous eATP produced by P. aeruginosa serves as a signalling molecule to co-ordinate complex multicellular behaviours of this pathogen. Given the propensity for P. aeruginosa to infect damaged epithelial tissues, our observations suggest that eATP released by damaged cells may provide a cue to reduce twitching motility of P. aeruginosa in order to establish infection at the site of damage. Furthermore, eATP produced by P. aeruginosa biofilms and by damaged epithelial cells may play a role in P. aeruginosa pathogenesis by inducing inflammatory damage and fibrosis. Our findings have significant implications in the development and pathogenesis of P. aeruginosa biofilm infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-015-0392-x) contains supplementary material, which is available to authorized users.

The biofilm matrix destabilizers, EDTA and DNaseI, enhance the susceptibility of nontypeable Hemophilus influenzae biofilms to treatment with ampicillin and ciprofloxacin

Nontypeable Hemophilus influenzae (NTHi) is a Gram-negative bacterial pathogen that causes chronic biofilm infections of the ears and airways. The biofilm matrix provides structural integrity to the biofilm and protects biofilm cells from antibiotic exposure by reducing penetration of antimicrobial compounds into the biofilm. Extracellular DNA (eDNA) has been found to be a major matrix component of biofilms formed by many species of Gram-positive and Gram-negative bacteria, including NTHi. Interestingly, the cation chelator ethylenediaminetetra-acetic acid (EDTA) has been shown to reduce the matrix strength of biofilms of several bacterial species as well as to have bactericidal activity against various pathogens. EDTA exerts its antimicrobial activity by chelating divalent cations necessary for growth and membrane stability and by destabilizing the matrix thus enhancing the detachment of bacterial cells from the biofilm. In this study, we have explored the role of divalent cations in NTHi biofilm development and stability. We have utilized in vitro static and continuous flow models of biofilm development by NTHi to demonstrate that magnesium cations enhance biofilm formation by NTHi. We found that the divalent cation chelator EDTA is effective at both preventing NTHi biofilm formation and at treating established NTHi biofilms. Furthermore, we found that the matrix destablilizers EDTA and DNaseI increase the susceptibility of NTHi biofilms to ampicillin and ciprofloxacin. Our observations indicate that DNaseI and EDTA enhance the efficacy of antibiotic treatment of NTHi biofilms. These observations may lead to new strategies that will improve the treatment options available to patients with chronic NTHi infections.

Non-cytotoxic silver nanoparticle-polyvinyl alcohol hydrogels with anti-biofilm activity: designed as coatings for endotracheal tube materials

Endotracheal intubation is commonly associated with hospital-acquired infections as the intubation device acts as reservoir for bacterial colonization in the lungs. To reduce the incidence of bacterial colonization on the tubes, hydrogel coatings loaded with antimicrobial agents are gaining popularity. The aim of this study was to incorporate silver nanoparticles (AgNPs) into polyvinyl alcohol (PVA) to form stable hydrogels. Embedding AgNPs into PVA resulted in a decreased elongation at break and an increased tensile strength compared to PVA alone. The Ag release profile varied as a function of the degree of hydrolysis of PVA: the higher degree of hydrolysis demonstrated a lower release rate. Fourier infrared transform spectroscopy demonstrated that AgNPs interacted exclusively with the -OH groups of PVA. AgNP-loaded PVA was non-toxic against human normal bronchial epithelial cells while effective against the attachment of Pseudomonas aeruginosa and Staphylococcus aureus with a greater effect on P. aeruginosa.

Silver nanoparticles enhance Pseudomonas aeruginosa PAO1 biofilm detachment

OBJECTIVES

Silver nanoparticles (AgNPs) with a size ranging from 7 to 70 nm were synthesized using the ascorbic acid-citrate seed-mediated growth approach at room temperature.

METHODS

The 8 nm silver particles were prepared using gallic acid in alkaline conditions and used as seed to prepare AgNPs.

RESULTS

The presence of ascorbic acid and citrate allows the regulation of size and size distribution of the nanoparticles. The increase in free silver ion-to-seed ratio (Ag(+)/Ag(0)) resulted in changes of particle shape from spherical to pseudo-spherical and minor cylindrical shape. Further, a repetitive seeding approach resulted in the formation of pseudo-spherical particles with higher polydispersity index and minor distributions of tetrahedral particles. Citrate-capped AgNPs were stable and did not agglomerate upon centrifugation. The effect of AgNPs on biofilm reduction was evaluated using static culture on 96-well microtiter plates. Results showed that AgNPs with the smallest average diameter were most effective in the reduction of Pseudomonas aeruginosa biofilm colonies, which accounted for 90% of removal.

CONCLUSION

The biofilm removal activities of the nanoparticles were found to be concentration-independent particularly for the concentration within the range of 80-200 µg/mL.

Superhydrophobic, nanotextured polyvinyl chloride films for delaying Pseudomonas aeruginosa attachment to intubation tubes and medical plastics

Bacterial attachment onto the surface of polymers in medical devices such as polyvinyl chloride (PVC) is influenced by the physicochemical properties of the polymer, including its surface hydrophobicity and roughness. In this study, to prevent biofilm formation onto PVC devices, the PVC surface was modified using a combination of solvent (tetrahydrofuran) and non-solvents (i.e. ethanol and methanol). The surface of unmodified PVC was smooth and relatively hydrophobic (water contact angle (CA)=80°). Ethanol-treated PVCs revealed the presence of micron-sized particulates and porous structures as the concentration of ethanol was increased. Surface hydrophobicity (measured in terms of CA) increased from 73° to 150° as the ethanol concentration increased from 15% to 35% (v/v). In general, methanol-treated PVCs were more hydrophilic compared to those treated with ethanol. The colonization of Pseudomonas aeruginosa PAO1 onto unmodified PVC surface was rapid, and individual bacterial cells could be seen after 6h incubation. On the surface of treated PVC, the secretion of extracellular matrix layers was evident at 18 h and P. aeruginosa PAO1 start to form microcolonies at 24h of incubation. The initial attachment of P. aeruginosa PAO1 was delayed to 18 and 24h, respectively in the PVCs treated with 25% (v/v) and 35% (v/v) ethanol. It can be concluded that the treatment used in this study to prepare superhydrophobic PVC surface prevented the colonization of bacteria up to 24h after culture.

MrkH, a novel c-di-GMP-dependent transcriptional activator, controls Klebsiella pneumoniae biofilm formation by regulating type 3 fimbriae expression

Klebsiella pneumoniae causes significant morbidity and mortality worldwide, particularly amongst hospitalized individuals. The principle mechanism for pathogenesis in hospital environments involves the formation of biofilms, primarily on implanted medical devices. In this study, we constructed a transposon mutant library in a clinical isolate, K. pneumoniae AJ218, to identify the genes and pathways implicated in biofilm formation. Three mutants severely defective in biofilm formation contained insertions within the mrkABCDF genes encoding the main structural subunit and assembly machinery for type 3 fimbriae. Two other mutants carried insertions within the yfiN and mrkJ genes, which encode GGDEF domain- and EAL domain-containing c-di-GMP turnover enzymes, respectively. The remaining two isolates contained insertions that inactivated the mrkH and mrkI genes, which encode for novel proteins with a c-di-GMP-binding PilZ domain and a LuxR-type transcriptional regulator, respectively. Biochemical and functional assays indicated that the effects of these factors on biofilm formation accompany concomitant changes in type 3 fimbriae expression. We mapped the transcriptional start site of mrkA, demonstrated that MrkH directly activates transcription of the mrkA promoter and showed that MrkH binds strongly to the mrkA regulatory region only in the presence of c-di-GMP. Furthermore, a point mutation in the putative c-di-GMP-binding domain of MrkH completely abolished its function as a transcriptional activator. In vivo analysis of the yfiN and mrkJ genes strongly indicated their c-di-GMP-specific function as diguanylate cyclase and phosphodiesterase, respectively. In addition, in vitro assays showed that purified MrkJ protein has strong c-di-GMP phosphodiesterase activity. These results demonstrate for the first time that c-di-GMP can function as an effector to stimulate the activity of a transcriptional activator, and explain how type 3 fimbriae expression is coordinated with other gene expression programs in K. pneumoniae to promote biofilm formation to implanted medical devices.

Biofilms are surface-associated communities of microorganisms. Biofilm-associated bacteria are protected from host defenses and antibiotics and are the cause of many infections. Klebsiella pneumoniae is primarily a hospital-acquired bacterial pathogen that causes pneumonia, urinary tract infections and septicemia. Its success is related to its ability to form biofilms on medical devices, such as catheters. In K. pneumoniae, biofilm formation is mediated by type 3 fimbriae – hair-like, protein appendages extending out from the cell surface that adhere to surfaces. This study investigated how K. pneumoniae regulates the expression of these fimbriae. We identified a protein, MrkH, which behaves as a “biofilm switch” that turns on the expression of genes responsible for producing type 3 fimbriae. MrkH works by binding to regulatory regions of DNA nearby to these genes and initiates their expression. Importantly, MrkH binds to DNA strongly only when the protein is stimulated by a small molecule, c-di-GMP. Furthermore, we identified bacterial enzymes that either produce or break down c-di-GMP to control its concentration within the cell, and thus modulate MrkH activity. Understanding the molecular basis for these processes may lead to the development of therapeutic compounds, possibly for incorporation into medical device materials to inhibit biofilm formation and pathogenesis.

Subclinical hyperthyroidism and sport eligibility: an exploratory study on cardiovascular pre-participation screening in subjects treated with levothyroxine for multinodular goiter

BACKGROUND

Subclinical hyperthyroidism (sHT) affects cardiovascular (CV) morphology and function; whether such changes can impact on sport eligibility is unclear.

AIM

This exploratory study evaluated the CV system and sport eligibility in athletes with levothyroxine-induced sHT, in the setting of mandatory pre-participation screening.

SUBJECTS AND METHODS

A full, non-invasive CV screening (history and physical examination, 12-lead ECG, echocardiography, 24-hour Holter ECG, exercise stress test) was performed in two groups of untrained female athletes affected by non-toxic multinodular goiter. One group was taking levothyroxine at mildly suppressive doses (TG) whereas the other was untreated (UG). There was also a group of healthy controls (HC).

RESULTS

In TG the following characteristics were observed: a) a higher resting heart rate (HR; p<0.01 and p<0.05, vs HC and UG respectively), b) a thicker left ventricular posterior wall (p<0.05 vs HC, and p<0.05 vs HC and UG, respectively), c) a higher mean HR during the 24-hour Holter ECG (p<0.01 and p<0.05, vs HC and UG respectively), and d) a lower achieved maximum work load (p<0.05, vs HC). No differences in the prevalence of cardiac arrhythmias among groups were observed. Sport eligibility was granted to all except one subject in the TG.

CONCLUSIONS

Although some alterations were found in athletes with levothyroxine-induced mild sHT, these are probably of limited clinical relevance and they did not contraindicate sport participation in the majority of cases. Future research to address both health risks and the need for specific evaluations (e.g. free thyroxine, TSH, echocardiography) during the preparticipation screening of athletes with sHT is warranted.

Trend in thyroid carcinoma size, age at diagnosis, and histology in a retrospective study of 500 cases diagnosed over 20 years

Recently, the Italian Network of Cancer Registries analyzed 5101 cases of thyroid carcinoma showing a reduction of mortality rate of 4%/year. This prompts us to evaluate the temporal trend in tumor size, age at diagnosis, and histology in a retrospective analysis of 500 thyroid cancers diagnosed over 20 years. Thyroid cancers were divided in two groups. The first included 193 cases diagnosed from 1985 to 1994, and the second 307 from 1995 to 2004. The size of all tumors was significantly reduced from 30 +/- 1.4mm in the first group to 15 +/- 0.8mm in the second group. In particular, papillary thyroid carcinoma (PTC) size decreased from 28 +/- 1.2mm to 14 +/- 0.8mm and follicular carcinoma from 40 +/- 6.3mm to 17 +/- 4.5 mm. Age at diagnosis of all carcinomas increased significantly from 40 +/- 1.3 years in the first group to 48 +/- 0.9 years in the second group. Analysis of the histological types revealed a significant increase of PTC rate in the second decade from 82% to 92% and a concomitant reduction of anaplastic thyroid carcinoma (ATC) from 3.7% to 1.0%. Moreover, a significant increase of micro-PTC rate, from 7.3% to 36.4%, was observed. In conclusion, it may be speculated that the above mentioned decreased mortality rate for thyroid carcinoma could be related to the significant reduction with time of cancer size, to the progressive increase of PTC rate and to the reduction of ATC rate. These data, if confirmed in other series, underscore the importance of evaluating thyroid nodules smaller than 10mm and corroborate recent findings suggesting that age be reconsidered as an independent prognostic factor for differentiated thyroid cancers.

Evidence for differences in the metabolism of saxitoxin and C1+2 toxins in the freshwater cyanobacterium Cylindrospermopsis raciborskii T3

The activity of paralytic shellfish poisoning (PSP) toxins biosynthetic enzymes was assayed in the cyanobacterium Cylindrospermopsis raciborskii T3 after inhibiting protein synthesis with chloramphenicol (CAM). The production of C1+2 and saxitoxin (STX) was sensitive to CAM with STX levels decreasing by 70% after 24-h exposure to the antibiotic. PSP toxin production was strongly promoted by arginine supplementation, with a maximum 476% increase in intracellular STX concentrations after 24-h exposure to 10 mM of the amino acid. However, arginine had no stimulating effect on PSP toxin levels if supplemented in combination with CAM at 10 microg l(-1). Addition of agmatine and proline to C. raciborskii T3 cultures in the presence of 10 microg l(-1) CAM increased C1+2 toxins levels, while having a negative or no effect on STX accumulation. In vitro, PSP toxin levels increased naturally in cyanobacterial extracts, with CAM and arginine having no influence on either C1+2 or STX synthesis. The evidence presented in this study suggests a possible difference between the metabolism of STX and the C1+2 toxins and indicated a high turnover rate of STX biosynthetic enzymes in C. raciborskii T3.

Reversible corpus callosum lesion in legionnaires' disease

Legionnaires' disease is often associated with neurological findings. Despite such findings, computed tomography and neuropathological investigations are typically normal. This report describes a reversible lesion of the corpus callosum identified on magnetic resonance imaging (MRI) in a patient with legionnaires' disease. MRI may show previously undocumented neuropathology in acute legionnaires' disease. Legionella pneumophila infection should be included in the differential diagnosis of conditions associated with reversible lesions of the corpus callosum.

Evaluation of a rapid immunochromatographic test for serodiagnosis of visceral leishmaniasis

The purpose of this study was to compare the performance of a rapid immunochromatographic dipstick test for the qualitative detection of circulating antibodies to the leishmanial recombinant antigen K39 with that of a classical immunofluorescent antibody test for serodiagnosis of visceral leishmaniasis. Sera from 143 Italian subjects, including 69 patients with clinically suspected visceral leishmaniasis, 23 patients with hypergammaglobulinemia and 51 healthy controls, were tested. The immunochromatographic test was performed according to the manufacturer's instructions, using antigen-impregnated nitrocellulose paper strips. The immunofluorescent antibody test was performed according to an established method, using promastigotes of Leishmania infantum zymodeme Montpellier 1 as antigen. In 11 patients, diagnosis of active Leishmania infection was established by microscopic examination of biopsy samples and/or clinical response to meglumine antimoniate. Results of the two tests correlated for all but two sera examined. In two patients, one with proven infectious mononucleosis and one with bacterial pneumonia, the immunofluorescent antibody test was positive and the dipstick test was negative. In the restricted sample of patients in whom a definitive diagnosis was established, the immunochromatographic test was positive in 11 of 11 patients with confirmed Leishmania infection and negative in 103 of 103 subjects who either had other documented diseases or were healthy controls, showing 100% sensitivity and 100% specificity.

Peritonectomy and hyperthermic antiblastic perfusion in the treatment of peritoneal carcinomatosis

AIMS

Some low-grade malignant tumours arising in the abdomen tend to remain loco-regionally confined to peritoneal surfaces, without systemic dissemination. In these cases complete surgical tumour cytoreduction followed by intra- or post-operative regional chemotherapy has curative potential. The aim of this study was to evaluate the outcome for patients treated in this way.

METHODS

Peritonectomy was performed, involving the complete removal of all the visceral and parietal peritoneum involved by disease. After peritonectomy, hyperthermic antiblastic perfusion was carried out throughout the abdominopelvic cavity for 90 min, at a temperature of 41.5-42.5 degrees C, with mitomycin C (3.3 mg/m2/l) and cisplatin (25 mg/m2/l) (for appendicular or colorectal primaries), or cisplatin alone (for ovarian primaries). Alternatively, the immediate post-operative regional chemotherapy was performed with 5-fluorouracil (13.5 mg/kg) and Lederfolin (125 mg/m2) (for colonic or appendicular tumours) or cisplatin (25 mg/m2) (for ovarian tumours), each day for 5 days.

RESULTS

Thirty-five patients affected by extensive peritoneal carcinomatosis were submitted to peritonectomy, with no residual macroscopic disease in all cases except three. Twenty-six patients were able to undergo the combined treatment involving loco-regional chemotherapy. Complications were observed in 54% of the patients and led to death in four of them. At a mean follow-up of 17 months overall 2-year survival was 55.2%, with a median survival of 26 months.

CONCLUSIONS

After a learning curve of 18 months the feasibility of the integrated treatment increased to more than 90%, while mortality decreased dramatically. The curative potential of the combined therapeutic approach seems high in selected patients with peritoneal carcinomatosis not responding to systemic chemotherapy. Careful selection of patients can minimize the surgical risk, but the treatment should currently be reserved for clinical trials.

Treatment of peritoneal carcinomatosis with intent to cure

BACKGROUND AND OBJECTIVES

Low-grade malignant tumors arise in the abdomen, do not infiltrate, and "redistribute" on the peritoneum with no extraregional spreading. In these cases, aggressive surgery combined with localized chemotherapy may provide cure.

METHODS

After removing the tumor with the regional peritoneum en bloc, intraabdominal hyperthermic chemoperfusion was performed throughout the abdominopelvic cavity. Alternatively, early intraabdominal chemotherapy, starting on the first postoperative day, was administered for 5 days.

RESULTS

Forty patients affected with extensive peritoneal carcinomatosis underwent peritonectomy, with no residual macroscopic disease except in four cases. Seventy-five percent of the patients underwent locoregional chemotherapy. Major complications were observed in 40% of the patients and led to death in five; there was a direct correlation to the duration of surgery (P = 0.03). At a mean follow-up of 20 months, the overall 2-year survival was 61.4%, with a median survival of 30 months.

CONCLUSIONS

After a learning curve of 18 months, the feasibility of the integrated treatment increased to greater than 90%, and mortality dramatically decreased. The combined treatment resulted in a high survival rate in patients with extensive carcinomatosis who were no longer responsive to traditional therapies.

Sentinel lymph node biopsy in cutaneous melanoma: the WHO Melanoma Program experience

BACKGROUND

We report the experience of the World Health Organization (WHO) Melanoma Program concerning sentinel lymph node (SLN) biopsy for detecting patients with occult regional nodal metastases to submit to selective regional node dissection.

METHODS

From February 1994 to August 1998, in 12 centers of the WHO Melanoma Program, 892 SLN biopsies were performed in 829 patients with clinical stage I melanoma (male: 370; female: 459; median age: 50 years old). The location of the primary melanoma was as follows: trunk 35%; lower limbs, 45%; upper limbs, 18%; and head and neck, 2%. Blue dye injection for SLN identification was performed in all cases; preoperative lymphoscintigraphy was done in 440 patients, and an intra-operative probe for a radio-guided biopsy was used in 141 cases. Overall, the SLN identification rate was 88%. In 68% of the patients, only one SLN was identified, whereas two and three or more SLN were detected in 24% and 8% of the remaining cases, respectively.

RESULTS

Overall SLN positivity rate was 18%. Intra-operative frozen section examination was performed in 39% of the cases and was helpful in detecting occult localizations only in 47% of the positive SLNs. Distribution of positive cases by primary thickness was as follows: < 1mm: 2%; 1-1.99 mm: 7%; 2-2.99 mm: 13%; and > or = 3 mm: 31%. Positive nonsentinel lymph nodes were found in 22% of cases with positive SLN submitted for selective dissection. No complications due to the procedure were registered. Of 710 patients who were evaluated, 40 (6%) presented a regional nodal relapse after a negative SLN biopsy and underwent a delayed therapeutic dissection. From the 710 enrolled cases, 638 (88.5%) were alive without evidence of disease at the time of this writing. A multivariate analysis showed SLN status as one of the most significant prognostic factors (P = .000) along with thickness (P = .001) and ulceration (P = .015) of primary tumor.

CONCLUSIONS

These data confirm the feasibility and safety of the SLN technique for selecting patients to submit to a radical node dissection. The data represent the basis for a future trial by the WHO Melanoma Program in this field to evaluate the most appropriate surgical approach for treating patients with occult regional nodal metastases.

Treatment of peritoneal carcinomatosis with intent to cure

BACKGROUND AND OBJECTIVES

Low-grade malignant tumors arise in the abdomen, do not infiltrate, and "redistribute" on the peritoneum with no extraregional spreading. In these cases, aggressive surgery combined with localized chemotherapy may provide cure.

METHODS

After removing the tumor with the regional peritoneum en bloc, intraabdominal hyperthermic chemoperfusion was performed throughout the abdominopelvic cavity. Alternatively, early intraabdominal chemotherapy, starting on the first postoperative day, was administered for 5 days.

RESULTS

Forty patients affected with extensive peritoneal carcinomatosis underwent peritonectomy, with no residual macroscopic disease except in four cases. Seventy-five percent of the patients underwent locoregional chemotherapy. Major complications were observed in 40% of the patients and led to death in five; there was a direct correlation to the duration of surgery (P = 0.03). At a mean follow-up of 20 months, the overall 2-year survival was 61.4%, with a median survival of 30 months.

CONCLUSIONS

After a learning curve of 18 months, the feasibility of the integrated treatment increased to greater than 90%, and mortality dramatically decreased. The combined treatment resulted in a high survival rate in patients with extensive carcinomatosis who were no longer responsive to traditional therapies.

Nerve-sparing surgery in rectal cancer: feasibility and functional results

Traditional rectal cancer surgery has been burdened with a high rate of sexual and urinary dysfunctions due to intraoperative injury or the cutting of the sympathetic and/or parasympathetic nerves. The experience acquired in the last ten years with total mesorectal excisions has permitted the use of the "nerve-sparing" technique. The present study regards 239 patients from two surgical centres, most of whom underwent sphincter-saving radical surgery between 1994 and 1998 with the above mentioned technique for resectable colon cancer. Details regarding the technique were recorded in the last 58 patients, in order to examine the severity of the surgical damage. The subgroup with the longest follow-up, which included 36 patients, was diagnostically evaluated by a surgeon, psychologist, urologist and neurologist to analyze the risk of sexual and urinary dysfunctions. A complete nerve-sparing was performed in 86.3% of the cases. The parasympathetic nerve trunks were those most often damaged because of perineural tumor spreading. Partial to complete sexual impotence was observed in 44% of the patients and surprisingly, preoperative dysfunctions were detected by means of the multidisciplinary approach in one third of these patients. Therefore, only 30.5% of the patients presented with strictly postoperative sexual impotency, above all, those who had undergone high-dose preoperative chemoradiation for T3 or T4 middle to low rectal cancer. A prospective study was initiated to evaluate the genitourinary dysfunctions after rectal cancer surgery in all of the clinical phases by means of a multidisciplinary approach aimed at functional recovery and improved quality of life.

Functioning and nonfunctioning thyroid adenomas involve different molecular pathogenetic mechanisms

The molecular biology of follicular cell growth in thyroid nodules is still poorly understood. Because gain-of-function (activating) mutations of the thyroid-stimulating hormone receptor (TShR) and/or Gs alpha genes may confer TSh-independent growth advantage to neoplastic thyroid cells, we searched for somatic mutations of these genes in a series of hyperfunctioning and nonfunctioning follicular thyroid adenomas specifically selected for their homogeneous gross anatomy (single nodule in an otherwise normal thyroid gland). TShR gene mutations were identified by direct sequencing of exons 9 and 10 of the TShR gene in genomic DNA obtained from surgical specimens. Codons 201 and 227 of the Gs alpha gene were also analyzed. At histology, all hyperfunctioning nodules and 13 of 15 nonfunctioning nodules were diagnosed as follicular adenomas. Two nonfunctioning thyroid nodules, although showing a prevalent microfollicular pattern of growth, had histological features indicating malignant transformation (a minimally invasive follicular carcinoma and a focal papillary carcinoma). Activating mutations of the TShR gene were found in 12 of 15 hyperfunctioning follicular thyroid adenomas. In one hyperfunctioning adenoma, which was negative for TShR mutations, a mutation in codon 227 of the Gs alpha gene was identified. At variance with hyperfunctioning thyroid adenomas, no mutation of the TShR or Gs alpha genes was detected in nonfunctioning thyroid nodules. In conclusion, our findings clearly define a different molecular pathogenetic mechanism in hyperfunctioning and nonfunctioning follicular thyroid adenomas. Activation of the cAMP cascade, which leads to proliferation but maintains differentiation of follicular thyroid cells, typically occurs in hyperfunctioning thyroid adenomas. Oncogenes other than the TShR and Gs alpha genes are probably involved in nonfunctioning follicular adenomas.

Hyperthermic antiblastic perfusion with alpha tumor necrosis factor and doxorubicin for the treatment of soft tissue limb sarcoma in candidates for amputation: results of a phase I study

To improve the therapeutic effectiveness of hyperthermic antiblastic perfusion (HAP), the association of recombinant tumor necrosis factor alpha (rTNF alpha), doxorubicin, and true hyperthermia (41 degrees C) was employed for the treatment of soft tissue limb sarcoma. A dose-escalation study according to Fibonacci's modified scheme was conducted, starting with a rTNF alpha dose of 0.5-3.3 mg. The doxorubicin doses (0.7 and 1.4 mg for the upper and lower limbs, respectively) and temperature level (41 degrees C) remained unchanged. Eighteen patients have been treated thus far: 9 males and 9 females of a mean age of 33 years (range: 24-71 years). The tumor was located in the upper limb in one patient and in the lower limbs in seventeen. Only 16 patients were evaluable, as 2 refused further treatment after the perfusion. In terms of local toxicity, a grade I limb reaction was observed in 3 patients, a grade II or III in 10 patients, and a grade IV in 5 patients, showing a strict correlation between the TNF dose and the grade of limb reaction. In fact, a grade III-IV limb reaction was observed in 66.6% of the patients treated with > 1 mg of rTNF alpha. The maximum tolerable dose in association with doxorubicin and true hyperthermia (41 degrees C) was 2.4 mg. Eleven patients showed a good pathological response (> 75%) and five patients showed a partial response (> 25%-< 75%). In no case was stable or progressive disease observed. The postperfusional tumor shrinkage permitted limb-sparing surgery in 75% of the patients, all of whom were candidates for amputation before HAP. No recurrences have been observed thus far. Two patients developed regional disease: one presented with a skip femur metastasis that disappeared after radiotherapy and systemic chemotherapy; the second developed regional node involvement, requiring a radical node dissection. Another patient had pulmonary metastases, 2 months after the HAP, which were resected. At a median follow-up of 12 months, all the patients are living without disease. The results of this phase I study suggest that the association of rTNF alpha, doxorubicin, and true HAP (41 degrees C) by regional perfusion is feasible and safe at a maximum tolerable rTNF alpha dose of 2.4 mg. However, because no correlation was found between the amount of rTNF alpha and the tumor response, 1 mg is recommended as the dose able to provide a high tumor necrosis rate and low local and systemic toxicity. This association appears to play an important role in the neoadjuvant treatment of soft tissue limb sarcoma.

The integrated treatment of peritoneal carcinomatosis. A preliminary experience

Some low-grade malignant tumors arising in the abdomen, lack of infiltrative attitude and "redistribute" on the peritoneum with no extraregional spreading. In this cases the complete tumor cytoreduction followed by intra- or postoperative regional chemotherapy has curative intent. Peritonectomy is the complete removal of all the parietal peritoneum and the visceral peritoneum involved by disease. After peritonectomy hyperthermic antiblastic perfusion is carried out throughout the abdomino-pelvic cavity for 60 minutes, at a temperature of 41.5 degrees C, with mitomycin C (3.3 mg/m2/Lt of perfusate) and cisplatin (25 mg/m2/Lt) (appendicular or colorectal primary), or cisplatin alone is (ovarian primary). Alternatively the immediate postoperative regional chemotherapy is performed with 5-fluorouracil (13.5 mg/Kg) and Lederfolin (125 mg/m2) (colic or appendicular tumor) or cisplatin (25 ng/m2) (ovarian tumor), each day for 5 days. Twenty patients affected by extensive peritoneal carcinomatosis (12 ovarian, 5 colonic, 1 appendicular, 1 mesothelial and 1 gastric primary) were submitted to peritonectomy with no residual macroscopic disease in all cases except three. Six patients were treated with intraoperative intra-abdominal hyperthermic antiblastic perfusion, while immediate postoperative intra-abdominal chemotherapy was given in 4 patients and systemic chemotherapy in other 5. Hospital mortality was 20%. At a mean follow-up of 11 months 14 patients are alive, 11 without disease and the median overall survival is 10.2 months. The curative potential of the combined therapeutic approach seems high in patients with peritoneal carcinomatosis from ovarian or colorectal primary not responding to systemic chemotherapy. Selection criteria of patients can strictly affect the surgical risk and the treatment has to be reserved for controlled clinical trials.

[Transient congenital hypothyroidism: physiopathology and clinica]

The fetus and the newborn are more sensitive than adults to a reduced environmental iodine supply, and in iodine-deficient areas, transient neonatal hypothyroidism is frequently observed. This transient thyroid failure may be associated with neonatal goiter and elevated serum thyroglobulin levels at birth. Borderline elevated neonatal serum TSH concentrations frequently occur in newborns in iodine deficient areas, and result in a higher recalling rate at the screening for congenital hypothyroidism. Minor defects in mental performances and neurological development are observed in children living in areas of mild to moderate iodine deficiency, and result from the concomitant effects of iodine deficiency in the mother during pregnancy and transient neonatal hypothyroidism. Endemic cretinism is the severe and irreversible neurological consequence of iodine deficiency during fetal and neonatal life. Iodine prophylaxis is highly effective in preventing the development of iodine deficiency disorders including transient neonatal hypothyroidism. Since iodine prophylaxis in Italy is inadequate, variable degrees of iodine deficiency are still present all-over the country, and are responsible of a higher incidence of transient neonatal hypothyroidism or hyperthyrotropinemia.

Chronic recurrent stress due to panic disorder does not precipitate Graves' disease

A role of psychic stress in precipitating hyperthyroid Graves' disease has been suggested, but the evidence in support of this pathogenetic mechanism is conflicting. In this study we investigated the possible occurrence of Graves' disease in patients with panic disorder, a psychiatric condition characterized by recurrent endogenous stress. The study group included 87 consecutive patients suffering from panic disorder since 1 to 30 years: 17 males (mean age 31.3, range 26-43 years) and 70 females (mean age 37.6, range 15-73 years). Two hundred and sixty-two normal subjects with no present or past history of psychiatric disorder served as controls. Patients were submitted to a full evaluation of the thyroid that included physical examination, assays for free thyroid hormones, TSH, thyroglobulin (TgAb), thyroperoxidase (TPOAb) and TSH receptor (TRAb) antibodies, and thyroid echography. The prevalence of circulating TgAb and/or TPOAb in patients with panic disorder did not differ from that in the control group. Twelve patients with panic disorder (13.7%) had circulating TgAb and/or TPOAb, but none had TRAb. Three out of 12 patients with thyroid antibodies, indicating a genetic susceptibility to autoimmune thyroid disease, had a family history of clinical thyroid autoimmunity, and 4 of them had a hypoechogenic pattern of the thyroid at ultrasound suggesting autoimmune thyroiditis. None of the patients with panic disorder had a previous history of hyperthyroidism. On examination, clinical hyperthyroidism or endocrine ophthalmopathy were not found in any of them. A small goiter was appreciated by palpation in 16 patients (18.3%). Free thyroid hormones and TSH were within the normal range in all patients but one: a 55-year old lady with normal serum free thyroid hormones and undetectable TSH. During an 18-month follow-up she did not develop hyperthyroidism and her TSH spontaneously returned in the normal range. Considering the individual duration of panic disorder, evidence for previous or present Graves' hyperthyroidism was not found for a total of 478 patient-years of exposure to recurrent endogenous stress in the whole study group, and for a total of 39 patient-years in patients with a genetic susceptibility to autoimmune thyroid disease. In conclusion, we found that recurrent endogenous stress did not precipitate Graves' hyperthyroidism in a series of 87 patients with panic disorder, encompassing a total of 478 patient-years of exposure to stress. Failure to activate the hypothalamic-pituitary-adrenal axis by endogenous stress due to panic disorder as opposed to exogenous stress due to life-events might explain why panic disorder does not precipitate Graves' hyperthyroidism.

Activating thyrotropin receptor mutations in histologically heterogeneous hyperfunctioning nodules of multinodular goiter

Activating thyrotropin (TSH) receptor mutations have been found in toxic adenomas and in hot nodules contained in toxic multinodular goiter. The typical feature of multinodular goiter is the heterogeneity in morphology and function of different follicles within the same enlarged gland. In this report we describe a patient with a huge multinodular goiter, normal free triiodothyronine (FT3) and free thyroxine (FT4) serum values, and subnormal TSH serum concentration. Thyroid scintiscan showed two hot areas corresponding to the basal and apical nodules of the left lobe. The right lobe was poorly visualized by the radioisotope. The patient underwent thyroidectomy, and histological examination of the tissue was performed. Genomic DNA was extracted from the tissue specimen and direct sequencing of the TSH receptor and Gs alpha genes was done. At histology, one hyperfunctioning nodule had the typical microscopic structure of thyroid adenomas, and the other contained multiple macrofollicular areas not confined by a capsule. In spite of this histological difference, both hyperfunctioning nodules harbored a mutation of the thyrotropin receptor (TSHr) gene: an isoleucine instead of a threonine in position 632 (T632I) in the first nodule and a methionine instead of an isoleucine in position 486 (I486M) in the second nodule. In conclusion, our findings show for the first time that gain-of-function TSHr mutations are not only present in hyperfunctioning thyroid nodules with the histological features of the true thyroid adenomas, but also in hyperfunctioning hyperplastic nodules contained in the same multinodular goiter.

The role of multiploidy as unfavorable prognostic variable in colorectal cancer

OBJECTIVE

To analyze the prognostic value of DNA multiploidy in a prospective study on frozen surgical tissue samples from primary colorectal cancer.

SUMMARY BACKGROUND DATA

Survival data from eleven prospective studies collectively comprising about thirteen hundred patients showed that aneuploidy correlated with a 5-year disease-free survival (DFS) significantly poorer than diploidy, and showed the limited prognostic value of results from retrospective studies employing paraffin-embedded material.

METHODS

Multiple tumor samples of fresh/frozen surgical tissues from 120 colorectal cancer patients who had undergone radical surgery were taken for flow cytometric analysis of DNA content, and proliferative activity, shown as percentage of cells in S-phase (%S). The minimum follow-up of this series was 30 months. Univariate and multivariate analyses determined the independent significance of both clinical and biological variable on DFS.

RESULTS

Values of %S equal to or higher than 17.3 correlated with a 5-year DFS poorer than values lower than 17.3 (44.5% vs 85.2% respectively; p = .03), even if only in patients younger than 64. The subgroup with multiploid tumors showed a significantly poorer 5-year DFS (44.5% vs. 62.6% in the non multiploid patients; p = .02). Subgrouping the Dukes'B stage alone by multiploidy, the difference in DFS was much more evident (31.2% vs. 68% respectively; p = .0004) and multivariate analysis showed multiploidy as the only significant variable. Above all, adjuvant therapy did not absolutely modify the unfavorable outcome of the multiploid Dukes'B patients.

CONCLUSIONS

The prospective evaluation of ploidy allowed us to identify a very high-risk subgroup of patients with multiploid tumors. This biological characterization was easy to demonstrate and, above all in node-negative patients, reliable and very effective in terms of prognosis. The presence of multiploidy should result in a more aggressive therapeutic approach in the adjuvant setting.

The application of hyperthermia in regional chemotherapy

To evaluate the role of hyperthermia combined with chemotherapy in the loco-regional treatment of tumors, a retrospective analysis was done with 228 limb melanoma patients treated with hyperthermic antiblastic perfusion (HAP). A series of treatment- and tumor-related prognostic factors was analyzed to establish their influence on tumor response, loco-regional control, and survival. Concerning tumor response, the logistic model showed that the number of lesions and the minimal tumor temperature (min T) maintained their individual predictive values (P < 0.000001 and P = 0.04, respectively). For loco-regional control, only the number of lesions had a significant predictive value. No direct correlation was found between the treatment-related variables and loco-regional control. However, the 5-year survival rate was significantly higher for patients who achieved a complete response (CR) (51.5%, P = 0.0033) as compared to those who did not (33.3%), providing indirect evidence of the role of the treatment. Multivariate analysis showed that both disease-free and overall survival are strongly influenced by numerous clinical variables and the min T always maintained its significance. When analyzing the subgroup of 119 patients evaluable for tumor response, the Cox model selected the tumor response as the dominant factor for both disease-free and overall survival. These data seem to demonstrate that the optimization of treatment parameters is crucial in determining the CR rate, which, in turn, positively affects the disease outcome. HAP is the treatment of choice for recurrent limb melanoma, and hyperthermia plays an important role in exploiting the efficacy of this technique.

S-100 and NSE as serum markers in melanoma

S-100 protein and neuron-specific enolase (NSE) have recently been proposed as serum markers for melanoma. In this study NSE and S-100 serum levels were assayed by commercial IRMA methods in 53 patients with melanoma. The overall prevalence of abnormal marker levels was similar for NSE (26%) and S-100 (30%). The 24 patients in stages I and II had uniformly normal S-100 levels, but abnormal NSE levels were observed in 3 out of the 12 patients in stage II (33%) and in 1 out of 12 in stage I. NSE appears thus to be the marker of choice in the early stages, where its increase points to disease progression. In patients in stages III and IV the prevalence of abnormal values was 34% for NSE and 55% for S-100 (p = < 0.05). In the latter group diagnostic sensitivity increased to 62% if isolated elevation of each marker was considered. In patients with advanced stage disease, both NSE and S-100 should be assayed.

Technetium-99m-MIBI scintigraphy in the assessment of neoadjuvant chemotherapy in breast carcinoma

Presurgical neoadjuvant chemotherapy (PSNC) is the treatment of choice for patients with locally advanced breast carcinoma (LABC). Accurate assessment of tumor response is important in planning subsequent treatments. Conventional response assessment by mammography and clinical evaluation is not fully reliable. This study evaluates the diagnostic yield of serial 99mTc-MIBI scintigraphy in the assessment of LABC response to PSNC.

METHODS

Twenty-nine patients affected by LABC underwent clinical, mammographic and 99mTc-MIBI scintigraphy before and after 3 cycles of FEC (500 mg/m2 5-fluorouracil, 50 mg/m2 epirubicin and 400 mg/m2 cyclophosphamide) on Days 1 and 8. Surgery was planned for 15 days after the third cycle of chemotherapy. Pathological status was obtained after surgery in all patients.

RESULTS

Sensitivities (i.e., true-positive ratios) for a correct prediction of tumor presence after PSNC were 65% for scintigraphy, 35% for clinical evaluation and 69% for mammography. Specificities (i.e., true-negative ratios) for a correct prediction of tumor absence after PSNC were 100% for scintigraphy, 67% for clinical evaluation and 33% for mammography. Technetium-99m-MIBI uptake in this series did not correlate with P-170 expression, proliferating cell nuclear antigen, Her-2/neu oncogene protein, antihuman endothelial cell CD31 antigen and estrogenic and progestinic receptor status.

CONCLUSION

Technetium-99m-MIBI scintigraphy is effective in monitoring the response to PSNC in LABC patients. Its diagnostic yield is clearly superior to clinical evaluation alone. Scintigraphy performs as does mammography in patients with negative response, but it is clearly superior in patients with positive response.