α-Synuclein fibril and synaptic vesicle interactions lead to vesicle destruction and increased lipid-associated fibril uptake into iPSC-derived neurons

Monomeric alpha-synuclein (aSyn) is a well characterised protein that importantly binds to lipids. aSyn monomers assemble into amyloid fibrils which are localised to lipids and organelles in insoluble structures found in Parkinson's disease patient's brains. Previous work to address pathological aSyn-lipid interactions has focused on using synthetic lipid membranes, which lack the complexity of physiological lipid membranes. Here, we use physiological membranes in the form of synaptic vesicles (SV) isolated from rodent brain to demonstrate that lipid-associated aSyn fibrils are more easily taken up into iPSC-derived cortical i3Neurons. Lipid-associated aSyn fibril characterisation reveals that SV lipids are an integrated part of the fibrils and while their fibril morphology differs from aSyn fibrils alone, the core fibril structure remains the same, suggesting the lipids lead to the increase in fibril uptake. Furthermore, SV enhance the aggregation rate of aSyn, yet increasing the SV:aSyn ratio causes a reduction in aggregation propensity. We finally show that aSyn fibrils disintegrate SV, whereas aSyn monomers cause clustering of SV using small angle neutron scattering and high-resolution imaging. Disease burden on neurons may be impacted by an increased uptake of lipid-associated aSyn which could enhance stress and pathology, which in turn may have fatal consequences for neurons.

Decreased Water Mobility Contributes To Increased α-Synuclein Aggregation

The solvation shell is essential for the folding and function of proteins, but how it contributes to protein misfolding and aggregation has still to be elucidated. We show that the mobility of solvation shell H2 O molecules influences the aggregation rate of the amyloid protein α-synuclein (αSyn), a protein associated with Parkinson's disease. When the mobility of H2 O within the solvation shell is reduced by the presence of NaCl, αSyn aggregation rate increases. Conversely, in the presence CsI the mobility of the solvation shell is increased and αSyn aggregation is reduced. Changing the solvent from H2 O to D2 O leads to increased aggregation rates, indicating a solvent driven effect. We show the increased aggregation rate is not directly due to a change in the structural conformations of αSyn, it is also influenced by a reduction in both the H2 O mobility and αSyn mobility. We propose that reduced mobility of αSyn contributes to increased aggregation by promoting intermolecular interactions.

Decreased Water Mobility Contributes To Increased α-Synuclein Aggregation

The solvation shell is essential for the folding and function of proteins, but how it contributes to protein misfolding and aggregation has still to be elucidated. We show that the mobility of solvation shell H2O molecules influences the aggregation rate of the amyloid protein α-synuclein (αSyn), a protein associated with Parkinson's disease. When the mobility of H2O within the solvation shell is reduced by the presence of NaCl, αSyn aggregation rate increases. Conversely, in the presence CsI the mobility of the solvation shell is increased and αSyn aggregation is reduced. Changing the solvent from H2O to D2O leads to increased aggregation rates, indicating a solvent driven effect. We show the increased aggregation rate is not directly due to a change in the structural conformations of αSyn, it is also influenced by a reduction in both the H2O mobility and αSyn mobility. We propose that reduced mobility of αSyn contributes to increased aggregation by promoting intermolecular interactions.

Intracellular Aβ42 Aggregation Leads to Cellular Thermogenesis

The aggregation of Aβ42 is a hallmark of Alzheimer’s disease. It is still not known what the biochemical changes are inside a cell which will eventually lead to Aβ42 aggregation. Thermogenesis has been associated with cellular stress, the latter of which may promote aggregation. We perform intracellular thermometry measurements using fluorescent polymeric thermometers to show that Aβ42 aggregation in live cells leads to an increase in cell-averaged temperatures. This rise in temperature is mitigated upon treatment with an aggregation inhibitor of Aβ42 and is independent of mitochondrial damage that can otherwise lead to thermogenesis. With this, we present a diagnostic assay which could be used to screen small-molecule inhibitors to amyloid proteins in physiologically relevant settings. To interpret our experimental observations and motivate the development of future models, we perform classical molecular dynamics of model Aβ peptides to examine the factors that hinder thermal dissipation. We observe that this is controlled by the presence of ions in its surrounding environment, the morphology of the amyloid peptides, and the extent of its hydrogen-bonding interactions with water. We show that aggregation and heat retention by Aβ peptides are favored under intracellular-mimicking ionic conditions, which could potentially promote thermogenesis. The latter will, in turn, trigger further nucleation events that accelerate disease progression.

Label-Free Characterization of Amyloids and Alpha-Synuclein Polymorphs by Exploiting Their Intrinsic Fluorescence Property

Conventional in vitro aggregation assays often involve tagging with extrinsic fluorophores, which can interfere with aggregation. We propose the use of intrinsic amyloid fluorescence lifetime probed using two-photon excitation and represented by model-free phasor plots as a label-free assay to characterize the amyloid structure. Intrinsic amyloid fluorescence arises from the structured packing of β-sheets in amyloids and is independent of aromatic-based fluorescence. We show that different amyloids [i.e., α-Synuclein (αS), β-Lactoglobulin (βLG), and TasA] and different polymorphic populations of αS (induced by aggregation in salt-free and salt buffers mimicking the intra-/extracellular environments) can be differentiated by their unique fluorescence lifetimes. Moreover, we observe that disaggregation of the preformed fibrils of αS and βLG leads to increased fluorescence lifetimes, distinct from those of their fibrillar counterparts. Our assay presents a medium-throughput method for rapid classification of amyloids and their polymorphs (the latter of which recent studies have shown lead to different disease pathologies) and for testing small-molecule inhibitory compounds.

Purification of Recombinant α-synuclein: A Comparison of Commonly Used Protocols

The initial state of the intrinsically disordered protein α-synuclein (aSyn), e.g., the presence of oligomers and degradation products, or the presence of contaminants and adducts can greatly influence the aggregation kinetics and toxicity of the protein. Here, we compare four commonly used protocols for the isolation of recombinant aSyn from Escherichia coli: boiling, acid precipitation, ammonium sulfate precipitation, and periplasmic lysis followed by ion exchange chromatography and gel filtration. We identified, using nondenaturing electrospray ionization mass spectrometry, that aSyn isolated by acid precipitation and periplasmic lysis was the purest and yielded the highest percentage of monomeric protein, 100% and 96.5%, respectively. We then show that aSyn purified by the different protocols exerts different metabolic stresses in cells, with the more multimeric/degraded and least pure samples leading to a larger increase in cell vitality. However, the percentage of monomeric protein and the purity of the samples did not correlate with aSyn aggregation propensity. This study highlights the importance of characterizing monomeric aSyn after purification, as the choice of purification method can significantly influence the outcome of a subsequent study.

Fast Purification of Recombinant Monomeric Amyloid-β from E. coli and Amyloid-β-mCherry Aggregates from Mammalian Cells

The Alzheimer's disease related peptide, Amyloid-beta (Aβ)1-40 and 1-42, has proven difficult to be purified as a recombinant monomeric protein due its expression in E. coli leading to the formation of insoluble inclusion bodies and its tendency to quickly form insoluble aggregates. A vast array of methods have been used so far, yet many have pitfalls, such as the use of tags for ease of Aβ isolation, the formation of Aβ multimers within the time frame of extraction, or the need to reconstitute Aβ from a freeze-dried state. Here, we present a rapid protocol to produce highly pure and monomeric recombinant Aβ using a one-step ion exchange purification method and to label the peptide using a maleimide dye. The washing, solubilization, and purification steps take only 3 h. We also present a protocol for the isolation of Aβ-mCherry from mammalian cells.

Intramitochondrial proteostasis is directly coupled to α-synuclein and amyloid β1-42 pathologies

Mitochondrial dysfunction has long been implicated in the neurodegenerative disorder Parkinson's disease (PD); however, it is unclear how mitochondrial impairment and α-synuclein pathology are coupled. Using specific mitochondrial inhibitors, EM analysis, and biochemical assays, we report here that intramitochondrial protein homeostasis plays a major role in α-synuclein aggregation. We found that interference with intramitochondrial proteases, such as HtrA2 and Lon protease, and mitochondrial protein import significantly aggravates α-synuclein seeding. In contrast, direct inhibition of mitochondrial complex I, an increase in intracellular calcium concentration, or formation of reactive oxygen species, all of which have been associated with mitochondrial stress, did not affect α-synuclein pathology. We further demonstrate that similar mechanisms are involved in amyloid-β 1-42 (Aβ42) aggregation. Our results suggest that, in addition to other protein quality control pathways, such as the ubiquitin-proteasome system, mitochondria per se can influence protein homeostasis of cytosolic aggregation-prone proteins. We propose that approaches that seek to maintain mitochondrial fitness, rather than target downstream mitochondrial dysfunction, may aid in the search for therapeutic strategies to manage PD and related neuropathologies.

Extent of N-terminus exposure of monomeric alpha-synuclein determines its aggregation propensity

As an intrinsically disordered protein, monomeric alpha-synuclein (aSyn) occupies a large conformational space. Certain conformations lead to aggregation prone and non-aggregation prone intermediates, but identifying these within the dynamic ensemble of monomeric conformations is difficult. Herein, we used the biologically relevant calcium ion to investigate the conformation of monomeric aSyn in relation to its aggregation propensity. We observe that the more exposed the N-terminus and the beginning of the NAC region of aSyn are, the more aggregation prone monomeric aSyn conformations become. Solvent exposure of the N-terminus of aSyn occurs upon release of C-terminus interactions when calcium binds, but the level of exposure and aSyn's aggregation propensity is sequence and post translational modification dependent. Identifying aggregation prone conformations of monomeric aSyn and the environmental conditions they form under will allow us to design new therapeutics targeted to the monomeric protein.

Isolation and Imaging of His- and RFP-tagged Amyloid-like Proteins from Caenorhabditis elegans by TEM and SIM

In our recently published paper, we highlight that during normal aging of C. elegans age-dependent aggregates of proteins form and lead to functional decline of tissues. The protocol described here details the isolation of two proteins from C. elegans in their aggregated amyloid-like form, casein kinase I isoform alpha (KIN-19) and Ras-like GTP-binding protein rhoA (RHO-1). We used nickel beads to isolate His-tagged KIN-19 and RHO-1, and thus permitting the isolation of both small and large aggregated or fibrillary forms of the proteins. We characterized their morphology by transmission electron microscopy. We further expressed RFP-tagged proteins and stained them with a fluorescent molecule, thioflavin T, which identifies β-sheet structures, and which is a defining feature of amyloid fibrils. We further applied structured illumination microscopy to determine the level of colocalization between RFP and thioflavin T.

Low energy optical excitations as an indicator of structural changes initiated at the termini of amyloid proteins

There is a growing body of experimental work showing that protein aggregates associated with amyloid fibrils feature intrinsic fluorescence. In order to understand the microscopic origin of this behavior observed in non-aromatic aggregates of peptides and proteins, we conducted a combined experimental and computational study on the optical properties of amyloid-derived oligopeptides in the near-UV region. We have focused on a few model systems having charged termini (zwitterionic) or acetylated termini. For the zwitterionic system, we were able to simulate the longer tail absorption in the near UV (250-350 nm), supporting the experimental results in terms of excitation spectra. We analyzed the optical excitations responsible for the low-energy absorption and found a large role played by charge-transfer states around the termini. These charge-transfer excitations are very sensitive to the conformation of the peptide and in realistic fibrils may involve inter and intra chain charge reorganization.

Intrinsically aggregation-prone proteins form amyloid-like aggregates and contribute to tissue aging in Caenorhabditis elegans

Reduced protein homeostasis leading to increased protein instability is a common molecular feature of aging, but it remains unclear whether this is a cause or consequence of the aging process. In neurodegenerative diseases and other amyloidoses, specific proteins self-assemble into amyloid fibrils and accumulate as pathological aggregates in different tissues. More recently, widespread protein aggregation has been described during normal aging. Until now, an extensive characterization of the nature of age-dependent protein aggregation has been lacking. Here, we show that age-dependent aggregates are rapidly formed by newly synthesized proteins and have an amyloid-like structure resembling that of protein aggregates observed in disease. We then demonstrate that age-dependent protein aggregation accelerates the functional decline of different tissues in C. elegans. Together, these findings imply that amyloid-like aggregates contribute to the aging process and therefore could be important targets for strategies designed to maintain physiological functions in the late stages of life.

C-terminal calcium binding of α-synuclein modulates synaptic vesicle interaction

Alpha-synuclein is known to bind to small unilamellar vesicles (SUVs) via its N terminus, which forms an amphipathic alpha-helix upon membrane interaction. Here we show that calcium binds to the C terminus of alpha-synuclein, therewith increasing its lipid-binding capacity. Using CEST-NMR, we reveal that alpha-synuclein interacts with isolated synaptic vesicles with two regions, the N terminus, already known from studies on SUVs, and additionally via its C terminus, which is regulated by the binding of calcium. Indeed, dSTORM on synaptosomes shows that calcium mediates the localization of alpha-synuclein at the pre-synaptic terminal, and an imbalance in calcium or alpha-synuclein can cause synaptic vesicle clustering, as seen ex vivo and in vitro. This study provides a new view on the binding of alpha-synuclein to synaptic vesicles, which might also affect our understanding of synucleinopathies.

Phylogeographic diversity and mosaicism of the Helicobacter pylori tfs integrative and conjugative elements

Background

The genome of the gastric pathogen Helicobacter pylori is characterised by considerable variation of both gene sequence and content, much of which is contained within three large genomic islands comprising the cag pathogenicity island (cagPAI) and two mobile integrative and conjugative elements (ICEs) termed tfs3 and tfs4. All three islands are implicated as virulence factors, although whereas the cagPAI is well characterised, understanding of how the tfs elements influence H. pylori interactions with different human hosts is significantly confounded by limited definition of their distribution, diversity and structural representation in the global H. pylori population.

Results

To gain a global perspective of tfs ICE population dynamics we established a bioinformatics workflow to extract and precisely define the full tfs pan-gene content contained within a global collection of 221 draft and complete H. pylori genome sequences. Complete (ca. 35-55kbp) and remnant tfs ICE clusters were reconstructed from a dataset comprising > 12,000 genes, from which orthologous gene complements and distinct alleles descriptive of different tfs ICE types were defined and classified in comparative analyses. The genetic variation within defined ICE modular segments was subsequently used to provide a complete description of tfs ICE diversity and a comprehensive assessment of their phylogeographic context. Our further examination of the apparent ICE modular types identified an ancient and complex history of ICE residence, mobility and interaction within particular H. pylori phylogeographic lineages and further, provided evidence of both contemporary inter-lineage and inter-species ICE transfer and displacement.

Conclusions

Our collective results establish a clear view of tfs ICE diversity and phylogeographic representation in the global H. pylori population, and provide a robust contextual framework for elucidating the functional role of the tfs ICEs particularly as it relates to the risk of gastric disease associated with different tfs ICE genotypes.

Electronic supplementary material

The online version of this article (10.1186/s13100-018-0109-4) contains supplementary material, which is available to authorized users.

ICSH recommendations for assessing automated high-performance liquid chromatography and capillary electrophoresis equipment for the quantitation of HbA2

Automated high performance liquid chromatography and Capillary electrophoresis are used to quantitate the proportion of Hemoglobin A2 (HbA2 ) in blood samples order to enable screening and diagnosis of carriers of β-thalassemia. Since there is only a very small difference in HbA2 levels between people who are carriers and people who are not carriers such analyses need to be both precise and accurate. This paper examines the different parameters of such equipment and discusses how they should be assessed.

ICSH: on board for new projects

The International Council for Standardization in Hematology (ICSH) is a not-for-profit organization aimed at improving global quality and harmonization of analytical methods, and achieving reliable and reproducible results in diagnostic hematology. ICSH co-ordinates Working Groups of experts to examine laboratory methods and instruments for hematological analyses, and co-operates with different international organizations which have similar scientific goals. Among seven ongoing approved projects, three ICSH projects have been selected and will be presented in the ICSH session at the XXVIIth ISLH International Symposium on Technological Innovations in Laboratory Hematology in The Hague, on May 2014. The project on 'Guideline for flow cytometric evaluation of patients with suspected acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS)' covers different aspects of the application of immunophenotyping by multiparameter flow cytometry (MFC) in the diagnosis of AML and MDS including integration into multimodal diagnostic workflow, quality control, antibody selection, interpretation of findings, reporting, and personnel. Data from the pilot study of the project for 'International Standardization of Hematology Reporting Units' suggest that there is a wide variation in reporting units for the routine blood cell count and highlights the areas of nomenclature and units of measurement where standardization is necessary and feasible, such as units for cell counts, white cell differentials, and hemoglobin concentration. The project on 'Standardization of HbA2 measurement and its implications for clinical practice' starts from the observation that different instruments give different results for hemoglobin A2; it is aimed at producing recommendations as to how instrument manufacturers and laboratories should assess their equipment before using it to analyze patient samples. These projects are examples of how the ICSH represents a great opportunity for scientists involved in hematology laboratory to participate in a process of expert collaboration and discussion all around the world.

The potential of electrospray ionization mass spectrometry for the diagnosis of hemoglobin variants found in newborn screening

Analytical procedures have been developed for the detection and diagnosis of sickle cell disease in newborn babies by analyzing the hemoglobin extracted from dried blood spots on Guthrie cards using electrospray ionization mass spectrometry (ESI-MS). An essential requirement is the ability to reliably differentiate two globin chains whose molecular weights differ by only 1 Da such as adult hemoglobin (Hb A) and Hb C. This has been achieved by improving the accuracy and precision of the molecular weight determination to a fraction of a dalton. We report the potential of mass spectrometry for screening neonates for these debilitating diseases by presenting results from 147 blood spots that had been characterized by phenotypic methods and which include samples from 20 sickle cell disease, 1 beta-thalassemia major, 57 sickle cell trait, and 39 normal babies. In all cases, the mass spectrometric results agreed with the results obtained using conventional analytical practice with high-performance liquid chromatography (HPLC) and isoelectric focusing (IEF). We show that mass spectrometry is a viable technique for the diagnosis of newborns with sickle cell disease or homozygous beta0-thalassemia.

Rapid identification of hemoglobin variants by electrospray ionization mass spectrometry

The precise identification of human hemoglobin variants, over 700 human hemoglobin variants are known, is essential for prediction of their clinical and genetic significance. A systematic approach to their rapid identification is described. Traditionally this requires protein or DNA characterization which entails lengthy analytical procedures. To overcome these obstacles a rapid approach to variant hemoglobin identification has been developed using conventional phenotypic methods combined with electrospray ionization-mass spectrometry (ESI-MS). The latter requires only a small amount of whole blood (10 microl) but in most cases 2 microl would have been sufficient and no preanalytical steps, such as separation of red cells or globin chains, are necessary. Aged, hemolyzed blood samples can also be analyzed. This approach has been used to positively identify 95% of the variants in over 250 samples. The remaining 5% in which a variant was detected by phenotypic techniques were not resolved by mass spectrometry. Ninety-nine different abnormalities comprising 36 alpha-chain variants, 59 beta-chain variants (including 2 extensions), and 4 hybrid hemoglobins were identified. These include 15 novel variants. The application of ESI-MS described requires approximately 1 h to prepare and analyze each sample and has minimal reagent costs. The turnaround time on a single sample can be as little as 2 h. This technique can now be considered a useful additional tool for reference laboratories.

Radiofrequency hyperthermia in the palliative treatment of mucinous carcinomatosis of appendiceal origin: optimizing and monitoring heat delivery in western patients

Mucinous peritoneal carcinomatosis from a primary gastrointestinal malignancy is a lethal condition that has few treatment options with the use of surgery, chemotherapy or radiation therapy. Recent advances in hyperthermia technology and in knowledge of the natural history of this disease has suggested the possible utility of hyperthermia in the application of aggressive local-regional therapy. Radiofrequency (RF) hyperthermia to the whole abdomen, to the hemithorax, or to an isolated mucinous tumour deposit obstructing the gastrointestinal tract was used in patients with disseminated mucinous adenocarcinoma of appendiceal origin. There were 228 hyperthermia treatments in 21 patients, with a median of 10 treatments per patient. The maximum number of treatments was 26, and minimum was one. For the first six hyperthermia treatments, escalating doses of deep hyperthermia (41-45 degrees C) was monitored with multiple sensor internal temperature probes and a single sensor subcutaneous temperature probe. After reaching a maximal hyperthermia treatment, this was maintained for all subsequent treatments. Initially, the maximal temperature allowed in tumour and subcutaneous tissue was 43 degrees C. After 50 hyperthermia treatments, this was changed to 45 degrees C. If disease stabilization or response was insufficient and maximal tolerable hyperthermia had been established, the frequency of treatment was increased from every 4 weeks to every 2 weeks, and escalating doses of mitomycin C at 8 mg/m2 were added to the regimen. Mitomycin C was infused during the hyperthermia treatment. For the first 165 treatments, patients were monitored just before and 10 days after hyperthermia with a complete blood count and a full battery of laboratory tests including amylase and lipase. Response was monitored by carcinoembryonic antigen assays on a monthly basis and CT scans on a 6 monthly basis. None of the 21 patients included in this study died, required intensive care, or required major surgical interventions as a result of hyperthermia treatments. One potentially life-endangering event was profound bradycardia and hypotension observed in a 76-year-old male receiving hyperthermia treatment to his right hemithorax. Two patients developed an enterocutaneous fistula (a frequent spontaneous event in this group of patients) while under treatment. No abnormal laboratory tests were observed in the first 165 hyperthermia treatments. Heat damage to normal tissue was limited to skin blisters in three patients and induration of the subcutaneous tissues in 10 patients. Skin pain on an analogue scale of 0-10 was scored by patients as a mean of 3.6 (range 0-8) before skin analgesia was routinely utilized. With anesthetic gel, the skin discomfort was greatly reduced. Prolonged abdominal pain for 4-20 days following treatment which required narcotic analgesia was seen in four patients. A complication rate of 62% was caused by the long-term indwelling temperature probe sheaths. Infection was observed in four patients, small bowel fistula in one, and dislodgement of the temperature probe sheath requiring repeat CT was necessary in seven patients. After maximal escalation of RF power in seven patients (33%), deep hyperthermia compatible with thermal destruction of tumour (> or = 43 degrees C for 45 min) was recorded in all subsequent treatments. In eight patients (38%), heat generation compatible with chemotherapy augmentation (41.5-43 degrees C) was consistently recorded. In six patients, non-therapeutic temperatures were recorded. There was no correlation of maximal tumour temperature, maximal subcutaneous tissue temperature and maximal RF power. With the use of skin anaesthetic there was no correlation of tumour temperature and the thickness of the subcutaneous layer of the skin. Progression was seen in 14 patients, and 11 of these patients died. No patients who showed disease stabilization have died with a minimum of 2 year follow-up. (ABSTRACT TRUNCATED)

Hemodynamic and cardiac function parameters during heated intraoperative intraperitoneal chemotherapy using the open "coliseum technique"

BACKGROUND

Heated intraoperative intraperitoneal chemotherapy achieves high peritoneal concentrations with limited systemic absorption and has become an important tool in the management of patients with peritoneal carcinomatosis from low-grade malignancies such as pseudomyxoma peritonei and in selected cases of high-grade tumors such as colon adenocarcinoma. When the closed abdomen technique is used, its perioperative toxicity seems to be related to the hemodynamic and cardiac function changes associated with increased body temperature and increased intra-abdominal pressure.

METHODS

Hemodynamic and cardiac function variables during heated intraoperative intraperitoneal chemotherapy, using an open abdomen "coliseum technique," were measured in 15 patients with the use of a noninvasive esophageal Doppler monitor.

RESULTS

The hemodynamic and cardiac function changes were characterized by an increased heart rate, increased cardiac output and decreased systemic vascular resistance associated with an increased body temperature, and decreased effective circulating volume with the urinary output tending to decrease as the therapy progressed.

CONCLUSION

Heated intraoperative intraperitoneal chemotherapy with the open abdomen coliseum technique induces a hyperdynamic circulatory state with an increased intravenous fluid requirement and avoids changes because of increased intra-abdominal pressure. Hemodynamic and cardiac stability, as documented by normal blood pressure and adequate urinary output, can be achieved by liberal intravenous fluids, titrated to frequent urinary output determination.

Morbidity and mortality analysis of 200 treatments with cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy using the coliseum technique

BACKGROUND

Peritoneal carcinomatosis from gastrointestinal cancers is a fatal diagnosis without special combined surgical and chemotherapy interventions. Guidelines for cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy (HIIC) by using the Coliseum technique have been developed to treat patients with peritoneal carcinomatosis and other peritoneal surface malignancies. The purpose of this study was to analyze the morbidity and mortality of patients undergoing cytoreductive surgery and HIIC by using mitomycin C.

METHODS

Data were prospectively recorded on 183 patients who underwent 200 cytoreductive surgeries with HIIC between November 1994 and June 1998. Seventeen of the 183 patients returned for a second-look surgery plus HIIC. All HIIC administrations occurred after cytoreduction and used continuous manual separation of intra-abdominal structures to optimize drug and heat distribution. Origins of the tumors were as follows: appendix (150 patients), colon (20 patients), stomach (7 patients), pancreas (2 patients), small bowel (1 patient), rectum (1 patient), gallbladder (1 patient), and peritoneal papillary serous carcinoma (1 patient). Morbidity was organized into 20 categories that were graded 0 to IV by the National Cancer Institute's Common Toxicity Criteria. In an attempt to identify patient characteristics that may predispose to complications, each morbidity variable was analyzed for an association with the 25 clinical variables recorded.

RESULTS

Combined grade III/IV morbidity was 27.0%. Complications observed included the following: peripancreatitis (6.0%), fistula (4.5%), postoperative bleeding (4.5%), and hematological toxicity (4.0%). Morbidity was statistically linked with the following clinical variables: duration of surgery (P < .0001), the number of peritonectomy procedures and resections (P < .0001), and the number of suture lines (P = .0078). No HIIC variables were statistically associated with the presence of grade III or grade IV morbidity. Treatment-related mortality was 1.5%.

CONCLUSIONS

HIIC may be applied to select patients with peritoneal carcinomatosis from gastrointestinal malignancies with 27.0% major morbidity and 1.5% treatment-related mortality. The frequency of complications was associated with the extent of the surgical procedure and not with variables associated with the delivery of heated intraoperative intraperitoneal chemotherapy. The technique has shown an acceptable frequency of adverse events to be tested in phase III adjuvant trials.

Heated intraoperative intraperitoneal mitomycin C and early postoperative intraperitoneal 5-fluorouracil: pharmacokinetic studies

PURPOSE

The purpose of this study was to report the pharmacokinetics of heated intraoperative intraperitoneal mitomycin C (MMC) and to analyze the impact of heat, extent of peritoneal resections, and effect of intraoperative hyperthermic chemotherapy on the pharmacological properties of the peritoneal plasma barrier.

METHODS

Sixty patients with peritoneal carcinomatosis were included in a phase I/II study combining cytoreductive surgery with 2 h of heated intraperitoneal mitomycin C in an intraoperative lavage technique and one cycle of early postoperative 5-fluorouracil (5-FU) given on postoperative days 1-5. Three pharmacokinetic analyses were performed: (1) pharmacokinetics of heated intraoperative intraperitoneal MMC was determined for 18 patients by sampling peritoneal fluid, plasma, and urine during the 2-h procedure; (2) impact of peritoneal resections on MMC pharmacokinetics was assessed by comparing a group of patients who underwent < or = 1 peritonectomy procedure (minimal surgery) to a group of patients who underwent > or = 2 peritonectomy procedures (extensive surgery), and (3) effects of heated intraoperative intraperitoneal chemotherapy on the pharmacokinetics of early postoperative intraperitoneal 5-FU by comparing a group of patients treated with heated intraoperative intraperitoneal MMC to a control group who did not receive heated intraoperative intraperitoneal chemotherapy.

RESULTS

The mean dose of heated intraoperative intraperitoneal MMC per patient was 22.5+/-7.1 mg (12.9+/-3.8 mg/m2). Drug absorption from perfusate was 14.3+/-2.7 mg. The mean aeras under the curve (AUC) for perfusate and plasma were, respectively, 340+/-138 and 15+/-4 microg/ml x min. The mean AUC peritoneal fluid/plasma ratio was 23.5+/-5.8. Patients who underwent extensive peritoneal resections exhibited a significantly (p = 0.037; Wilcoxon rank test) increased peak plasma concentration of MMC, a significantly (p = 0.029) increased AUC of plasma concentrations and a significantly (p = 0.034) decreased peritoneal fluid/plasma AUC ratio. Pharmacokinetic studies of early postoperative intraperitoneal 5-FU showed no significant difference in plasma AUC, perfusate AUC and AUC ratio between patients who received and those who did not receive heated intraoperative intraperitoneal MMC.

CONCLUSIONS

Heated intraoperative intraperitoneal chemotherapy achieves high peritoneal concentrations of MMC with limited systemic absorption. Systemic drug absorption during heated intraoperative intraperitoneal chemotherapy is increased when extensive peritoneal resections are performed, but such slight increases are unlikely to change the risk of systemic drug toxicities. Heated intraoperative intraperitoneal chemotherapy does not alter the pharmacokinetics of early postoperative intraperitoneal 5-FU.

The use of automated HPLC to detect and quantitate haemoglobins

The introduction of automation for haemoglobinopathy screening is an important advance in technology for haematology laboratories. This paper evaluates the utility of an automated HPLC instrument, the Bio-Rad 'Variant' for the detection and quantitation of the normal haemoglobins (Hb A, A2 and F) and the common abnormal haemoglobins (Hb S, C, DPunjab, E, OArab and Lepore) which need to be evaluated in laboratories undertaking carrier and/or neonatal screening for sickle cell and thalassaemia. The instrument only uses a small amount of whole blood (5 microliters), a 3 mm disc from a Guthrie spot may also be used for analysis of samples from neonates. It uses a 100 place automatic sampler with a cycle time of 6.5 min for adult samples (using the 'Beta Thalassaemia Short' reagent pack) and 3 min for neonatal samples. The automatic sampler also allows samples to be analysed 'out of hours'. A 'STAT'; position allows urgent samples to be analysed before, or during, a routine analytical run. All reagents, other consumables and application notes are provided by the suppliers. Other types of reagent packs, such as the 'Sickle Cell Short' for neonatal screening were not assessed during this study.

Analysis of morbidity and mortality in 60 patients with peritoneal carcinomatosis treated by cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy

BACKGROUND

Peritoneal carcinoma has been regarded as a uniformly lethal clinical entity. A treatment plan combining cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy (HIIC) was devised and tested to treat such patients. The purpose of this study was to evaluate the morbidity and mortality associated with this treatment approach.

METHODS

Sixty patients with peritoneal carcinomatosis from adenocarcinoma of the colon or appendix were included in the study. Extensive cytoreductive surgery was combined with heated intraperitoneal mitomycin in an intraoperative lavage technique followed by one cycle of early postoperative intraperitoneal 5-fluorouracil. Eleven clinical variables were selected and statistically correlated with morbidity and mortality.

RESULTS

Twenty-five complications occurred in 21 patients (morbidity = 35%). Morbidity related to gastrointestinal function included anastomotic leak (n=6), bowel perforations (n=5), bile leak (n=3), and pancreatitis (n=2). Four patients presented with severe hematologic toxicity (Grade 3 or 4). There were three cases of postoperative bleeding, one case of abdominal wound dehiscence, and one case of pulmonary embolism. Morbidity was significantly associated with three clinical factors: male sex, high intraabdominal temperature during HIIC, and duration of the surgical procedure. Enteral complications (bowel fistula and anastomotic leak) occurred in patients with a significantly higher number of peritonectomy procedures and a significantly longer operation. Three patients died within 8 weeks after the procedure (mortality = 5%). Mortality was significantly associated with age and intraabdominal temperature.

CONCLUSIONS

Cytoreductive surgery combined with HIIC is associated with a 35% morbidity rate and a 5% mortality rate. Extensive surgery (duration and number of peritonectomy procedures) and high intraabdominal temperature represent the major risk factors for postoperative morbidity and mortality of patients treated with this new therapeutic approach.

Analysis of morbidity and mortality in 60 patients with peritoneal carcinomatosis treated by cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy

BACKGROUND

Peritoneal carcinoma has been regarded as a uniformly lethal clinical entity. A treatment plan combining cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy (HIIC) was devised and tested to treat such patients. The purpose of this study was to evaluate the morbidity and mortality associated with this treatment approach.

METHODS

Sixty patients with peritoneal carcinomatosis from adenocarcinoma of the colon or appendix were included in the study. Extensive cytoreductive surgery was combined with heated intraperitoneal mitomycin in an intraoperative lavage technique followed by one cycle of early postoperative intraperitoneal 5-fluorouracil. Eleven clinical variables were selected and statistically correlated with morbidity and mortality.

RESULTS

Twenty-five complications occurred in 21 patients (morbidity = 35%). Morbidity related to gastrointestinal function included anastomotic leak (n=6), bowel perforations (n=5), bile leak (n=3), and pancreatitis (n=2). Four patients presented with severe hematologic toxicity (Grade 3 or 4). There were three cases of postoperative bleeding, one case of abdominal wound dehiscence, and one case of pulmonary embolism. Morbidity was significantly associated with three clinical factors: male sex, high intraabdominal temperature during HIIC, and duration of the surgical procedure. Enteral complications (bowel fistula and anastomotic leak) occurred in patients with a significantly higher number of peritonectomy procedures and a significantly longer operation. Three patients died within 8 weeks after the procedure (mortality = 5%). Mortality was significantly associated with age and intraabdominal temperature.

CONCLUSIONS

Cytoreductive surgery combined with HIIC is associated with a 35% morbidity rate and a 5% mortality rate. Extensive surgery (duration and number of peritonectomy procedures) and high intraabdominal temperature represent the major risk factors for postoperative morbidity and mortality of patients treated with this new therapeutic approach.

Analysis of morbidity and mortality in 60 patients with peritoneal carcinomatosis treated by cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy

BACKGROUND

Peritoneal carcinoma has been regarded as a uniformly lethal clinical entity. A treatment plan combining cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy (HIIC) was devised and tested to treat such patients. The purpose of this study was to evaluate the morbidity and mortality associated with this treatment approach.

METHODS

Sixty patients with peritoneal carcinomatosis from adenocarcinoma of the colon or appendix were included in the study. Extensive cytoreductive surgery was combined with heated intraperitoneal mitomycin in an intraoperative lavage technique followed by one cycle of early postoperative intraperitoneal 5-fluorouracil. Eleven clinical variables were selected and statistically correlated with morbidity and mortality.

RESULTS

Twenty-five complications occurred in 21 patients (morbidity = 35%). Morbidity related to gastrointestinal function included anastomotic leak (n=6), bowel perforations (n=5), bile leak (n=3), and pancreatitis (n=2). Four patients presented with severe hematologic toxicity (Grade 3 or 4). There were three cases of postoperative bleeding, one case of abdominal wound dehiscence, and one case of pulmonary embolism. Morbidity was significantly associated with three clinical factors: male sex, high intraabdominal temperature during HIIC, and duration of the surgical procedure. Enteral complications (bowel fistula and anastomotic leak) occurred in patients with a significantly higher number of peritonectomy procedures and a significantly longer operation. Three patients died within 8 weeks after the procedure (mortality = 5%). Mortality was significantly associated with age and intraabdominal temperature.

CONCLUSIONS

Cytoreductive surgery combined with HIIC is associated with a 35% morbidity rate and a 5% mortality rate. Extensive surgery (duration and number of peritonectomy procedures) and high intraabdominal temperature represent the major risk factors for postoperative morbidity and mortality of patients treated with this new therapeutic approach.

Hyperthermic intraoperative intraperitoneal chemotherapy safety considerations

Perioperative staff members encounter many occupational exposure hazards in the workplace. Cytotoxic agent exposure is a relatively new hazard that perioperative staff members are experiencing as more surgeons use hyperthermic intraoperative intraperitoneal chemotherapy (HIIC) to treat patients with abdominopelvic cavity malignancies. Routes of exposure include inhalation, ingestion, injection, and skin contact. The National Cancer Institute, the Occupational Safety and Health Administration, and the Joint Commission on Accreditation of Healthcare Organizations provide guidelines for the safe administration and handling of cytotoxic agents. Institutions in which cytotoxic agents are administered should use these guidelines to develop policies, procedures, and educational programs to protect surgical patients and perioperative staff members.

Safety constiderations in the use of intraoperative intraperitoneal chemotherapy

The clinical significance of occupational exposure to antineoplastic agents is controversial. Accrued evidence does not seem to indicate mutagenicity, carcinogenicity, and tertogenicity when exposure is limited by proper precautions. However, medical surveillance of personnel continually exposed to these cytotoxic agents will aid in early detection of any problems should they occur. Because the current fiscal milieu constantly emphasizes cost containment, true prevention means an intense worker education program. Personnel continually exposed to these cytotoxic agents should have scheduled health checkups twice a year, and exposure frequency should be reported to the employee's personal physician.

Surgically directed chemotherapy: heated intraperitoneal lavage with mitomycin C

This chapter reported the pharmacokinetics and the toxicities of mitomycin-c (MMC) when administered as a hyperthermic intraperitoneal lavage after surgical resection of advanced primary or recurrent gastrointestinal cancer. Pharmacologic studies were performed in 10 patients and all adverse reactions were recorded in 20 patients. These 20 patients had advanced gastrointestinal malignancies with peritoneal carcinomatosis and underwent cytoreductive surgery prior to intraperitoneal lavage. Heated (42 degrees C) intraperitoneal mitomycin C was used in a lavage technique with 30 mg/3 1 of drug for 2 hours. The fluid was distributed throughout the abdominal cavity by vigorous external massage of the abdominal wall. This resulted in approximately 70 percent (21 mg) drug absorption from the perfusate. Urine output of MMC averaged 2.5 mg during the 2 hour procedure. Median peak blood levels of 0.25 micrograms/ml (range 0.11-0.41 micrograms/ml) were observed at 45-60 minutes into the procedure. Morbidity was low and was mainly related to the surgical procedures (prolonged ileus, postoperative fistulas) with mild to moderate drug-related myelosuppression. This new method of delivery of MMC and 5-FU should be explored in phase II clinical trials.

Intraoperative hyperthermic lavage with cisplatin for peritoneal carcinomatosis and sarcomatosis

Intraoperative hyperthermic lavage with cisplatin was studied in 8 patients with peritoneal carcinomatosis and sarcomatosis. A dose of 50 mg/m2 of cisplatin used for 2 hours with an intraperitoneal temperature of 41 degrees to 43 degrees C was used. Pharmacokinetic studies showed that cisplatin left the abdomen and pelvis by simple diffusion with a half life of 48 minutes in the peritoneal fluid. Eighty-six percent of the drug was absorbed into the plasma within 2 hours but only 6.9% was excreted into the urine. The area under the curve ratio for peritoneal fluid to plasma was 6.9. The quantity of cisplatin in tissue from the abdomen or pelvis was extremely variable. It was 1.85-10.28 micrograms cisplatin/g tumor and < 0.57-7.90 micrograms/g normal tissue. Comparison of pharmacologic parameters of hyperthermic to normothermic cisplatin administration showed no significant differences.

Hyperthermic intraoperative intreperitoneal chemotherapy (HIIC) with mitomycin C

Dedrick et al. published a mathematical model in 1978 that described the theoretical rationale for in- traperitoneal administration of chemotherapeutic agents.' Numerous authors have provided substantial clinical and experimental evidence supporting Dedrick's model. Lukas et al.' and Torres et al.' have de- scribed the pharmacokinetics involved in the transport of drugs from the peritoneal cavity into the portal and systemic circulation. These investigations and others gave birth to the pharmacologic concept known as the peritoneal plasma barrier (PPB). The PPB has been described as a complex diffusion barrier, consisting of the endothelium, the mesothelium, and the intervening interstitium, along with the fluid in the blood and the dialysate.t This physiologic barrier limits the resorption of hydrophilic drugs such as mitomycinC, doxoru- bicin, and cisplatin from the peritoneal cavity into the blood.

Cancer recurrence following laparoscopic colectomy. Report of two patients treated with heated intraperitoneal chemotherapy

PURPOSE

Use of laparoscopic techniques for resection of colon and rectal cancer has raised considerable controversy. There is increasing concern that wound recurrence and peritoneal dissemination may represent a potentially fatal complication of this technique.

METHODS

The surgical literature was reviewed, and clinical course of two patients is presented.

RESULTS

Our two patients had tumor recurrence in the laparoscopy port sites within one year after laparoscopic assisted colectomy for Dukes B adenocarcinoma of the colon. At laparotomy, diffuse peritoneal carcinomatosis without lymph node or liver metastases were found in both patients. They were treated by surgical resection of recurrent disease combined with heated intraoperative intraperitoneal mitomycin C chemotherapy and five days of early postoperative intraperitoneal 5-fluorouracil. These patients are clinically free of disease at 1.5 years after treatment of peritoneal implants.

CONCLUSIONS

Cancer recurrence in abdominal wall incisions after laparoscopic colectomy has been reported in an increasing number of patients. It is possible that this technique should be abandoned. Cytoreductive surgery combined with intraperitoneal chemotherapy may represent the most adequate treatment of recurrent cancer that occurs following laparoscopic colectomy.

Pharmacokinetic studies of intraaortic stop-flow infusion with 14C-labeled mitomycin C

This pharmacokinetic study attempted to improve the exposure of gastrointestinal tract tissues to chemotherapy by increasing the transit time of a first pass of a drug through the vascular system. Bolus infusion of 9 mg mitomycin (MMC) mixed with 1 mg of MMC labeled by 50 microCi of 14C was performed in 18 mongrel dogs. Pharmacokinetics of MMC in peripheral, portal, and aortic blood were studied under different types of major vessel occlusion. Three dogs with intravenous infusion constituted a control group. In 15 dogs MMC was infused intraaortically with the catheter's tip at the level of the celiac and superior mesenteric artery. Vascular flow was controlled in four different ways for 30 min: Type I-Type IV. In Type IV the abdominal aorta and vena cava inferior were occluded after surgical exclusion of all nongastrointestinal branches of aorta. Blood samples were obtained during a 90-min period. After solubilizing the samples, 14C-labeled MMC activity was counted by a scintillation counter. For stop-flow infusion Type I, II, III, and IV, area under the curve (AUC) ratios for portal blood versus systemic circulation were 1.6:1, 2.9:1, 2.9:1, and 8.8:1, respectively (statistically significant for Types II, III, and IV). The highest value of AUC, peak MMC concentration, and lowest clearance in portal blood were achieved in SFI Type IV. Exposure to MMC was the greatest with SFI Type IV, making this type of aortic stop-flow infusion the most favorable mode of drug administration from a pharmacokinetic perspective.

Intraaortic stop-flow infusion: pharmacokinetic feasibility study of regional chemotherapy for unresectable gastrointestinal cancers

BACKGROUND

This study attempted to increase the exposure of gastrointestinal tract tissues to chemotherapy by prolonging the first pass of intraaortically administered drug by temporary occlusion of vascular structures.

METHODS

Bolus infusion of 14C-labeled mitomycin C (MMC) mixed with unlabeled MMC was performed in dogs. Distribution of MMC in gastrointestinal tract tissues was studied under different types of major vessel occlusion. Three dogs with intravenous infusion constituted the control group. Vascular flow was controlled in four ways for 30 min: type I--stop-flow infusion (SFI) with clamping of the abdominal aorta above the celiac and below inferior mesenteric artery; type II--with additional clamping of the inferior vena cava above the diaphragm; type III with additional clamping of the portal vein in the hepatoduodenal ligament; and type IV--with surgical exclusion of nongastrointestinal branches of the aorta in addition to type II clamping.

RESULTS

Type II and IV produced a 3-10-fold increase in exposure to MMC of major gastrointestinal tissues as compared with intravenous infusion. Area under the curve ratios with type IV were most prominent in the following tissues: stomach, pancreas, liver, and mesenteric lymph node.

CONCLUSION

Access of MMC to several gastrointestinal tissues was increased through SFI. Type IV infusion was the most effective. Tissue exposure to MMC was especially advantageous for stomach, pancreas, liver, and mesenteric lymph node.

False-positive lymph nodes by radioimmunoguided surgery: report of a patient and analysis of the problem

Preoperative administration of radiolabeled monoclonal antibody allows radioimmunoguided surgery with hand-held intraoperative detection devices. From a theoretical perspective, this technology may offer more knowledgable patient management and more complete resection of intra-abdominal cancer. False-positive examinations may seriously jeopardize the widespread application of this apparatus. Our experience with a patient with false-positive lymph nodes following administration of 125I-labeled B72.3 monoclonal antibody is reported. After careful histopathological analysis of five nodes thought to be false-positive for cystadenocarcinoma, one lymph node was found to have a minute nidus of cancer. The cause of false-positive radioimmunoguided tests and their implications for the clinical use of this tool is discussed. We interpreted our data to suggest that tumor antigen-monoclonal antibody complexes processed in reactive lymph nodes, anatomically draining the malignant tissue, may cause false-positive tests.

Enhanced platelet reactivity and hypercoagulability in the steady state of sickle cell anaemia

A prospective controlled study was undertaken to investigate the haemostatic and coagulation status of 18 adult subjects in the steady state of sickle cell anaemia (SCA), using a relatively new in vitro technique. Shear induced haemostasis, whole blood dynamic coagulation, and spontaneous thrombolysis were measured using nonanticoagulated blood. As expected, the haemoglobin levels were significantly lower and platelet counts significantly higher in subjects with SCA compared with controls. Haemostasis and coagulation were significantly enhanced in SCA. No correlation was found between the raised platelet count and enhanced haemostasis or the reduced haemoglobin and hypercoagulation, respectively. Hyperactivity of the haemostatic system may have a pathogenic role in vaso-occlusive microthrombotic events and in the leg ulcers, both of which occur frequently in SCA.

Cystinuria and its treatment: 25 years experience at St. Bartholomew's Hospital

Cystinuria is an inherited condition affecting the active transport of the diamino acids cystine, ornithine, lysine and arginine across the renal tubule and the small intestine. The only clinical effect is the production of urinary tract stones and if these can be prevented the affected individuals can lead a normal life. In many people cystine stones can be dissolved and new stone formation prevented by a high fluid intake, but if this does not succeed regular treatment with penicillamine will do so. Although many side-effects have been described with penicillamine treatment it is rare for them to be severe enough to prevent its use in patients with cystinuria. Since the clinical effects of cystinuria can be prevented by either a high fluid intake or by penicillamine it is important to make the diagnosis in affected individuals as soon as possible and cystinuria should therefore be considered in all people (regardless of age) who form urinary stones.

A distant gene deletion affects beta-globin gene function in an atypical gamma delta beta-thalassemia

We describe an English family with an atypical gamma delta beta-thalassemia syndrome. Heterozygosity results in a beta-thalassemia phenotype with normal hemoglobin A2. However, unlike previously described cases, no history of neonatal hemolytic anemia requiring blood transfusion was obtained. Gene mapping showed a deletion that extended from the third exon of the G gamma-globin gene upstream for approximately 100 kilobases (kb). The A gamma-globin, psi beta-, delta-, and beta-globin genes in cis remained intact. The malfunction of the beta-globin gene on a chromosome in which the deletion is located 25 kb away suggests that chromatin structure and conformation are important for globin gene expression.

Pseudoxanthoma elasticum-like skin changes induced by penicillamine

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