Individualized lung recruitment maneuver guided by pulse-oximetry in anesthetized patients undergoing laparoscopy: a feasibility study

BACKGROUND

We conducted this study to test whether pulse-oximetry hemoglobin saturation (SpO₂ ) can personalize the implementation of an open-lung approach during laparoscopy. Thirty patients with SpO₂  ≥ 97% on room-air before anesthesia were studied. After anesthesia and capnoperitoneum the FIO₂ was reduced to 0.21. Those patients whose SpO₂ decreased below 97% - an indication of shunt related to atelectasis - completed the following phases: (1) First recruitment maneuver (RM), until reaching lung's opening pressure, defined as the inspiratory pressure level yielding a SpO₂ ≥ 97%; (2) decremental positive end-expiratory (PEEP) titration trial until reaching lung's closing pressure defined as the PEEP level yielding a SpO₂  < 97%; (3) second RM and, (4) ongoing ventilation with PEEP adjusted above the detected closing pressure.

RESULTS

When breathing air, in 24 of 30 patients SpO₂ was < 97%, PaO₂ /FIO₂  ˂ 53.3 kPa and negative end-expiratory transpulmonary pressure (P_TP-EE ). The mean (SD) opening pressures were found at 40 (5) and 33 (4) cmH₂ O during the first and second RM, respectively (P < 0.001; 95% CI: 3.2-7.7). The closing pressure was found at 11 (5) cmH₂ O. This SpO₂ -guided approach increased P_TP-EE (from -6.4 to 1.2 cmH₂ O, P < 0.001) and PaO₂ /FIO₂ (from 30.3 to 58.1 kPa, P < 0.001) while decreased driving pressure (from 18 to 10 cmH₂ O, P < 0.001). SpO₂ discriminated the lung's opening and closing pressures with accuracy taking the reference parameter P_TP-EE (area under the receiver-operating-curve of 0.89, 95% CI: 0.80-0.99).

CONCLUSION

The non-invasive SpO₂ monitoring can help to individualize an open-lung approach, including all involved steps, from the identification of those patients who can benefit from recruitment, the identification of opening and closing pressures to the subsequent monitoring of an open-lung condition.

Individualised perioperative open-lung approach versus standard protective ventilation in abdominal surgery (iPROVE): a randomised controlled trial

BACKGROUND

The effects of individualised perioperative lung-protective ventilation (based on the open-lung approach [OLA]) on postoperative complications is unknown. We aimed to investigate the effects of intraoperative and postoperative ventilatory management in patients scheduled for abdominal surgery, compared with standard protective ventilation.

METHODS

We did this prospective, multicentre, randomised controlled trial in 21 teaching hospitals in Spain. We enrolled patients who were aged 18 years or older, were scheduled to have abdominal surgery with an expected time of longer than 2 h, had intermediate-to-high-risk of developing postoperative pulmonary complications, and who had a body-mass index less than 35 kg/m². Patients were randomly assigned (1:1:1:1) online to receive one of four lung-protective ventilation strategies using low tidal volume plus positive end-expiratory pressure (PEEP): open-lung approach (OLA)-iCPAP (individualised intraoperative ventilation [individualised PEEP after a lung recruitment manoeuvre] plus individualised postoperative continuous positive airway pressure [CPAP]), OLA-CPAP (intraoperative individualised ventilation plus postoperative CPAP), STD-CPAP (standard intraoperative ventilation plus postoperative CPAP), or STD-O₂ (standard intraoperative ventilation plus standard postoperative oxygen therapy). Patients were masked to treatment allocation. Investigators were not masked in the operating and postoperative rooms; after 24 h, data were given to a second investigator who was masked to allocations. The primary outcome was a composite of pulmonary and systemic complications during the first 7 postoperative days. We did the primary analysis using the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02158923.

FINDINGS

Between Jan 2, 2015, and May 18, 2016, we enrolled 1012 eligible patients. Data were available for 967 patients, whom we included in the final analysis. Risk of pulmonary and systemic complications did not differ for patients in OLA-iCPAP (110 [46%] of 241, relative risk 0·89 [95% CI 0·74-1·07; p=0·25]), OLA-CPAP (111 [47%] of 238, 0·91 [0·76-1·09; p=0·35]), or STD-CPAP groups (118 [48%] of 244, 0·95 [0·80-1·14; p=0·65]) when compared with patients in the STD-O₂ group (125 [51%] of 244). Intraoperatively, PEEP was increased in 69 (14%) of patients in the standard perioperative ventilation groups because of hypoxaemia, and no patients from either of the OLA groups required rescue manoeuvres.

INTERPRETATION

In patients who have major abdominal surgery, the different perioperative open lung approaches tested in this study did not reduce the risk of postoperative complications when compared with standard lung-protective mechanical ventilation.

FUNDING

Instituto de Salud Carlos III of the Spanish Ministry of Economy and Competitiveness, and Grants Programme of the European Society of Anaesthesiology.

From service quality in organisations to self-determination at home

BACKGROUND

In our proposed model, family members' perceptions of service quality in organisations improve communication about self-determination. In turn, family perceptions of communication openness have a positive relationship with self-determination attitudes of family members. Finally, these attitudes predict self-determination behaviours of individuals with intellectual disability, as reported by family members.

METHOD

We tested this model with a sample of 625 family members (196 using 'day care services' and 429 using 'occupational services').

RESULTS

Multi-sample structural equation modelling (SEM) supported the model. Communication and attitudes fully mediated the link from service quality to self-determination behaviours.

CONCLUSIONS

Improving family members' perceptions of service quality and opening channels of communication between professionals and family members are useful strategies to facilitate parents' positive attitudes and increase the frequency of self-determination behaviours at home.

Prospective randomized trial comparing conventional laparoscopic colectomy with hand-assisted laparoscopic colectomy: applicability, immediate clinical outcome, inflammatory response, and cost

BACKGROUND

Hand-assisted laparoscopic surgery (HALS) represents a useful alternative to conventional laparoscopic surgery (LS). Its potential advantages--(a quicker, safer procedure and less need to convert to open surgery) are due to the recovery of tactile feedback. However, HALS requires the performance of a mini-laparotomy when surgery commences, and the wound is stretched and compressed throughout the procedure. In addition, it is associated with a more intense manipulation of the intraabdominal viscera. All of these factors increase the surgical trauma, it is not known whether HALS maintains the minimally invasive characteristics of conventional LS. Therefore, we set out to study the applicability, immediate clinical outcome, inflammatory response, and cost of HALS compared with conventional LS using colectomy as a model.

METHODS

We performed a prospective randomized trial comparing laparoscopic-assisted colectomy with HAL colectomy. The aims of the study were to assess (a) perioperative features, including time, advantages, and conversion; (b) the patient's immediate clinical response, including recovery of bowel sounds, refeeding time, postoperative pain, local and general morbidity, and hospital stay; (c) the effect on the inflammatory response, using interleukin-6 (ILG) and C-reactive protein (CRP) measurements; (d) oncological issues, including intraoperative cytology and features of the specimen; and (d) the relative costs of the two procedures.

RESULTS

A total of 54 patients were enrolled in the study, 27 laparoscopic and 27 HALS. The operative times were similar, but HALS was associated with a far lower conversion rate--7% vs 23%. Immediate clinical outcomes, oncological features, and costs were similar for the two procedures, but HALS was associated with a significantly greater increase in IL6 and CRP than the conventional laparoscopic procedure.

CONCLUSION

This comparative study shows that HALS simplifies difficult intraoperative situations, reducing the need for conversion. Although it is a more aggressive procedure, HALS preserves the features of a minimally invasive approach, maintains all of the oncological features of conventional laparoscopic surgery, and does not increase the cost. HALS should therefore be considered as a useful adjunct when difficult situations arise during conventional laparoscopic colectomy.

A simple infection model using pre-colonized implants to reproduce rat chronic Staphylococcus aureus osteomyelitis and study antibiotic treatment

Staphylococcus aureus biofilms formed on medical implants represent a serious problem, being difficult to eradicate with antibiotic therapy and leading to chronic infections. Simplified in vivo and in vitro antibiotic susceptibility assays using biofilm bacteria are needed. In this work, a novel chronic osteomyelitis infection model was developed in rats in the absence of bacterial suspension, requiring the use of only 10(6) bacteria in biofilms at the site of surgery, with a full success in reproducing infection. Stainless-steel implants pre-colonized for 12 h with a highly adherent S. aureaus isolate were introduced into the rat tibiae. In animals not submitted to antibiotic treatment, infection was found in the implants and spread to bone in all cases, indicating the high efficacy of the model to reproduce osteomyelitis. The effect of a 21-day treatment with cefuroxime, vancomycin, tobramycin or ciprofloxacin on infection was studied in this model 42 days after surgery. Bone colonization was inhibited by vancomycin and cefuroxime. Cefuroxime (the most efficient antibiotic, able to sterilize 1 out of 8 implants) reduced the number of bacteria in biofilms adhered to implants at a higher extent than vancomycin, trobramycin and ciprofloxacin. Analogous observations were made in this work in vivo and in vitro on the relative antibiotic efficacy against S. aureus biofilm bacteria. suggesting the usefulness of both tests as a potential tool to study antibiotic suceptibility, and the need for new antimicrobials against these bacteria.

Results of laparoscopic splenectomy for treatment of malignant conditions

BACKGROUND

Laparoscopic splenectomy (LS) is widely accepted for treatment of benign diseases, but there are few reports of its use in cases of haematological malignancy. In addition, comparative studies with open operation are lacking. Malignant haematological diseases have specific clinical features-notably splenomegaly and impaired general health-which can impact on the immediate outcome after LS. The immediate outcome of LS comparing benign with malignant diagnoses has been analysed in a prospective series of 137 operations.

PATIENTS AND METHODS

Between February 1993 and April 2000, 137 patients with a wide range of splenic disorders received LS. Clinical data and immediate outcome were prospectively recorded,and age, diagnosis, operation time, perioperative transfusion requirement, spleen weight, conversion rate, accessory incision, hospital stay and complications were analysed.

RESULTS

The series included 100 benign cases and 37 suspected malignancies. In patients with malignant diseases the mean age was greater (37 years [3-85] vs 60 years [27-82], p<0.01), LS took longer (138 min [60-400] vs 161 min [75-300], p<0.05) and an accessory incision for spleen retrieval was required more frequently (18% vs 93%, p<0.01) because the spleen was larger (279 g [60-1640] vs 1210 g [248-3100], p <0.01). However, the rate of conversion to open operation (5% vs 14%), postoperative morbidity rate (13% vs 22%) and transfusion requirement (15% vs 26%) did not differ between benign and malignant cases. Hospital stay was longer in malignant cases (3.7 days [2-14] vs 5 days [2-14], p<0.05).

CONCLUSION

LS is a safe procedure in patients with malignant disease requiring splenectomy in spite of the longer operative time and the higher conversion rate.

[Laparoscopic treatment of colorectal polyps]

Endoscopic removal is the treatment of choice for colorectal polyps. However, this therapeutic option is limited by the size of the tumor, sessile implantation, or technical impossibility. These cases are ideal for laparoscopic treatment because of the anatomy of the colon is and because the risk of manipulating a malignant lesion is lower. However, there is the added difficulty of identifying the lesion. In other cases, unsuspected neoplastic invasion of an endoscopically removed polyp makes surgery necessary.

AIM

To evaluate the results of laparoscopic surgery in the treatment of colorectal polyps.

MATERIAL AND METHODS

Between December 1997 and November 1999, 270 endoscopic polypectomies were performed. In 15 patients, endoscopic removal was technically impossible or contraindicated. These patients were treated laparoscopically. One patient who was found to have an invasive carcinoma following polypectomy was also treated laparoscopically. The technical characteristics of the operation (duration, conversion, morbi-mortality, postoperative stay, size of the polyp and number of ganglions) were analyzed and compared with 43 other laparoscopic operations in the colon carried out for other reasons (n = 43).

RESULTS

In nine patients, surgery was indicated because of the size of the polyp, in three for technical reasons, in three for severe atypia and in one because of an invasive carcinoma following polypectomy. The operation was completed by laparoscopy in 15 patients (94%). Ten right hemicolectomies, five sigmoidectomies and one anterior resection assisted by hand port were carried out. The diameter of the lesions was 4.4 +/- 2.4 cm. Histological studies revealed carcinoma in situ in five, infiltrating carcinoma in two, non-malignant adenoma in six and lipoma in one. Comparison of the results of patients who underwent colectomy for polyps with those of the group who underwent surgery for other reasons revealed lower morbidity (24% vs. 22%) and need for conversion (7% vs. 16%), as well as a significant decrease in operating time (130 +/- 10 vs. 148 +/- 32 min, p < 0.05) and in postoperative stay (6.6 +/- 1.4 vs. 8.3 +/- 2.5 days, p < 0.02).

CONCLUSION

Laparoscopic colonic resection is particularly suitable in the treatment of colorectal polyps.

Antibiotic susceptibility assay for Staphylococcus aureus in biofilms developed in vitro

Four slime-producing isolates of Staphylococcus aureus were used in an antibiotic susceptibility assay for biofilms developed on 96-well polystyrene tissue culture plates. The study involved 11 antibiotics, two biofilm ages (6 and 48 h), two biofilm growth media (tryptone soy broth (TSB) and delipidated milk) and three antibiotic concentrations (4 x MBC, 100 mg/L and 500 mg/L). ATP-bioluminescence was used for automated bacterial viability determination after a 24 h exposure to antibiotics, to avoid biofilm handling. Under the conditions applied, viability in untreated biofilms (controls) was lower when biofilm growth was attempted in milk rather than in TSB. Various antibiotics had a greater effect on viability when used at higher (> or =100 mg/L) antibiotic concentrations and on younger (6 h) biofilms. Increased antibiotic effect was observed in milk-grown rather than TSB-grown biofilms. Phosphomycin and cefuroxime, followed by rifampicin, cefazolin, novobiocin, vancomycin, penicillin, ciprofloxacin and tobramycin significantly affected biofilm cell viability at least under some of the conditions tested. Gentamicin and erythromycin had a non-significant effect on cell viability. Transmission electron microscopy revealed that cells at the inner biofilm layers tend to remain intact after antibiotic treatment and that TSB-grown biofilms favoured a uniformity of cell distribution and increased cell density in comparison with milk-grown biofilms. A reduced matrix distribution and enhanced cell density were observed as the biofilm aged. The S. aureus biofilm test discriminated antibiotics requiring shorter (3 h or 6 h) from those requiring longer (24 h) exposure and yielded results which may be complementary to those obtained by conventional tests.

In vitro development of Staphylococcus aureus biofilms using slime-producing variants and ATP-bioluminescence for automated bacterial quantification

In this work, a method was developed to establish Staphylococcus aureus biofilms on 96-well plates and automatically quantify viable cells within these biofilms by ATP-bioluminescence. Different strains were compared for biofilm formation. Cells from slime producing (SP) strain variants were more adherent (p < 0.001) and therefore more suitable for biofilm formation than non-slime producing original isolates. To compare biofilm support surfaces, SP biofilms were formed for 6, 24 and 48 h on 96-well polystyrene plates, containing wells coated with gelatin, poly-L-lysine or pre-treated for tissue culture and uncoated wells. Tissue culture-treated wells enhanced biofilm formation, allowing the highest growth (p < 0.001) in well-established biofilms (24 or 48 h old). For ATP quantification, the efficacy of different ATP extractants was compared: dimethyl sulphoxide (DMSO), trichloroacetic acid (TCA), a commercially available releasing reagent(R) (RR) and lysostaphin. A greater inhibitory effect on the ATP detection (p < 0.01), a more variable light emission (variation coefficient >/=50% vs. <19%, respectively) and a lower extraction efficiency (p < 0.05) were found in the case of TCA or lysostaphin in relation to RR or DMSO. DMSO was found preferable in relation to RR (upper detection limits 2.3 x 10(9) and 2 x 10(8) CFU/mL respectively) for bacterial ATP extraction from biofilms with high bacterial density. DMSO extracted ATP within seconds, light emission being stable for 6 h. The method developed allows automated viability determination of biofilm cells using bioluminescence and simultaneous study of factors affecting this viability (culture media, antibiotic types, antimicrobial concentrations, support surfaces and biofilm ages). It may be of use in bacteriological and antimicrobial research.

Application of a rat osteomyelitis model to compare in vivo and in vitro the antibiotic efficacy against bacteria with high capacity to form biofilms

A rat experimental osteomyelitis model was used to study the efficiency of antibiotics on biofilm bacteria adhered to implants in relation to the efficiency obtained in vitro. In the osteomyelitis model, 10(4) bacteria of the strain variant used for the in vitro studies (a slime-producing variant of Staphylococcus aureus) were inoculated into the rat tibia at surgery, after implanting a stainless steel canula precolonized for 12 h with this strain. After 5 weeks, a 21-day antibiotic treatment was applied (using cefuroxime, vancomycin, or tobramycin). Subsequently, implant and tibia were studied for presence of bacteria. In this osteomyelitis model, cefuroxime inhibited bone colonization and reduced the number of bacteria in metal and bone at a higher degree (P < 0.05) than vancomycin and trobramycin (the latter antibiotic did not have this reduction effect). The in vitro assay was applied using three concentrations of each antibiotic (8, 100, and 500 microg/ml) and 6-, 24-, and 48-h biofilms. Bacterial viability was evaluated by ATP-bioluminescence after 24 h of antibiotic treatment. In this in vitro assay, cefuroxime significantly (P < 0.05) reduced in all cases the number of viable bacteria in biofilms, tobramycin did not affect viability, and vancomycin affected viability except at the lowest concentration used (8 microg/ml, i.e., 8x the minimal bactericidal concentration of this antibiotic) when facing the oldest (48 h) biofilm. These results demonstrate the usefulness of the osteomyelitis model applied in providing evidence for a close correlation between the in vitro and in vivo findings on the effect of three antibiotics under study.

Adherence of Staphylococcus aureus slime-producing strain variants to biomaterials used in orthopaedic surgery

The adherence of Staphylococcus aureus to biomaterials used in orthopaedic surgery (polymethylmethacrylate, fresh bone, steel and titanium alloys) and to glass was studied in vitro at 1, 2, 6, 24 and 48 h of incubation. Nonslime-producing strains (72, 80 and 510) and slime-producing variants of these strains were used. An automated and fast method of ATP-bioluminiscence was applied to determine bacterial viability. The lowest adherence corresponded to polymethylmethacrylate and bone, and the highest to metals. Significant adherence was detected in all cases after 6 h and was strain dependent, being lowest for strain 72. In most cases, adherence of nonslime-producing variants was not significant compared with controls, and slime-producing were more adherent than nonslime-producing variants. These differences were maximal at 6 h or 48 h, depending on the strain and the material. The findings suggest that the appearance of slime-producing cells within a given nonslime-producing bacterial population may jeopardise postoperative immune systems and antibiotic efficacy as a consequence of biofilm formation on implants and prostheses.

Isolation of chromosome-specific ESTs by microdissection-mediated cDNA capture

Despite dramatic advances in the identification of human expressed sequence tags (ESTs), techniques that facilitate isolation of chromosome or chromosome band-specific ESTs would be of considerable value. This report demonstrates the feasibility of identifying chromosome-specific ESTs following microdissection of a single-copy chromosome region. For this study, a reduced complexity cDNA library was linkered and hybridized to normal human metaphase chromosomes. After stringency washes, the entire long arm of chromosome 6 (6q) was microdissected. Following PCR amplification using linker-specific primers, captured cDNAs were subcloned and 187 individual clones picked at random. These 187 clones were then sorted by filter cross-hybridization into 34 unique groups. Of these 34 groups, 19 (56%) mapped to chromosome 6 by Southern blot. We identified three previously known genes, human cytovillin (ezrin) mapped previously to 6q25-26, human cardiac gap junction protein (connexin 43) mapped previously to 6q21-23.2 and prolyloligopeptidase, which had not been mapped previously. BLASTN identified three clone groups with homology to known ESTs and 12 representing novel cDNA sequences. Six of the groups were sublocalized to specific band regions of 6q using a chromosome 6 hybrid mapping panel, five representative clones were tested on Northern analysis to verify their expression, and finally, nine clones were mapped against the Gene bridge 4 reduction hybrid panel to confirm their genetic map location on 6q. These results demonstrate that microdissection of single-copy sequences has sufficient specificity for isolation of chromosome-specific cDNAs.

Identification of region specific genes by chromosome microdissection

Chromosome microdissection is an extremely useful molecular cytogenetic tool for the characterization of chromosomal abnormalities in tumor cells. Although it has been used primarily in conjunction with fluorescence in situ hybridization (FISH), microdissection has also been useful for molecular analysis via microclone library construction. Recently, microdissection has been applied to the isolation of region specific cDNAs with sufficient success that gene discovery can now be added to the list of applications of this versatile molecular cytogenetic technique.

Use of microgenomic technology for analysis of alterations in DNA copy number and gene expression in malignant melanoma

Chromosome abnormalities in human malignancies have identified the genomic location of several important growth-regulatory genes, including cellular oncogenes and tumour suppressor genes. Melanomas are characterized by recurring chromosome alterations, and it is important to identify those genes whose altered expression may be causally related to melanocytic transformation. This short report presents an overview of strategies used which combine the materials and technologies of the Human Genome Project with clinically directed studies of melanoma biology. The Human Genome Project combines various technologies, including cytogenetic, physical mapping, genetic mapping and DNA sequencing, in order to identify all of the human genes, but especially the 4000 estimated to contribute to human disease. This report focuses first on advances in genome technology that provide information on chromosome rearrangements and DNA copy number changes. This includes a discussion of chromosome microdissection as well as the microexcision of tissue specimens to gain insights into chromosome regions altered in association with melanocyte transformation. Next, there is a brief discussion of the generation and characterization of subtracted cDNA sublibraries which allow the identification of genes uniquely expressed in association with the transformed phenotype of human melanoma cells. Finally, we briefly discuss the feasibility of using a recently developed system for parallel examination of multiple genes based upon robotic printing of cDNAs on glass slides, and simultaneous two-colour fluorescence hybridization to study the expression patterns of cDNAs for their association with melanoma tumour suppression. The combination of these varied molecular technologies may provide insights into previously unrecognized genes involved causally in the pathobiology of this important neoplasm, and may provide new targets for clinical intervention.

Isolation of genes amplified in human cancers by microdissection mediated cDNA capture

It has been increasingly recognized that homogeneously staining regions (hsr) in human cancers may be complex structures composed of large amplified DNA domains containing multiple genes. It is therefore important to devise strategies for the rapid isolation of cDNAs expressed from these structures. Using a procedure we term microdissection mediated cDNA capture, we recovered hsr specific cDNAs from two different human tumors. The glioblastoma cell line TX3868 and the human sarcoma cell line OsA-CL carry hsrs containing amplified sequences from chromosome 12q13-15. We recovered 17 hsr specific cDNAs following microdissection of these hsrs which had been previously hybridized in situ with linkered cDNA. Northern blot analysis with these cDNAs revealed hybridization to distinct transcripts in OsA-CL RNA and TX3868 RNA. None of the OsA-CL cDNA clones showed cross hybridization with the TX3868 cDNAs suggesting that despite their coincident band localization on 12q, the OsA-CL and TX3868 amplification units do not completely overlap. These results significantly increase the number of amplified genes assigned to the 12q13-15 amplicon illustrating both the complexity of hsrs derived from this region and the utility of microdissection mediated cDNA capture to gain rapid access to cDNAs transcribed from amplified genes.

Visible but unreported: a case for the "not serious enough" cases of child maltreatment

This study examined the psychosocial characteristics of cases of child maltreatment labelled as "not serious enough." The sample consisted of cases of suspected physical abuse (N = 48), neglect (N = 13), and psychological maltreatment (N = 8) identified by teachers, and a nonabused comparison group (N = 283). Characteristics of children and their parents were evaluated at three ecological levels: individual, family, and social. Results indicated a poor personal and social adjustment of the children in the maltreatment groups, and suggest that the definition of cases of maltreatment as not serious enough does not represent the psychological reality of these children. Discriminant analysis indicated that the most important variables for discriminating between all maltreatment groups and the nonabuse group were parents and children's perceptions of parental behavior, children's behavioral problems and personal adjustment, parents integration and satisfaction in the community, and the importance and direction of personal growth emphasized in the family. The importance of other variables such as socioeconomic status, stress, psychological symptoms or number of children appeared to be a function of the different types of child maltreatment. The importance of prevention and intervention efforts before the maltreatment reaches a serious stage is discussed.

Ponceau S as a dye for quantitative protein assay. Its use in the presence of Triton X-100

A Ponceau S reagent with high stability and slight response to pH changes, presence of organic solvents and detergents was prepared. Under these conditions, the reagent was tested to be suitable to quantify, in one-step procedure, different standard proteins. Moreover, this method offers the possibility to measure the protein content in the presence of the detergent Triton X-100.