Desorption Dynamics of Rb2 Molecules Off the Surface of Helium Nanodroplets.

The desorption dynamics of rubidium dimers (Rb2) off the surface of helium nanodroplets induced by laser excitation is studied by employing both nanosecond and femtosecond ion imaging spectroscopy. Similarly to alkali metal atoms, we find that the Rb2 desorption process resembles the dissociation of a diatomic molecule. However, both angular and energy distributions of detected Rb2+ ions appear to be most crucially determined by the Rb2 intramolecular degrees of freedom rather than by those of the Rb2HeN complex. The pump-probe dynamics of Rb2+ is found to be slower than that of Rb+, pointing at a weaker effective guest-host repulsion for excited molecules than for single atoms.

Clinical Factors Implicated in Primary Graft Dysfunction After Heart Transplantation: A Single-center Experience.

BACKGROUND: Primary graft dysfunction (PGD) is a frequent complication after cardiac transplantation and remains one of the leading causes of mortality in these patients. The objective of this case-control study is to identify donor and surgical procedure's factors associated with PGD, and further guide possible strategies to prevent PGD. METHODS: Retrospective analysis of the medical records of patients who underwent cardiac transplantation at Memorial Hermann Hospital at Texas Medical Center between October 2012 and February 2015. RESULTS: The study population included 99 patients, of which 18 developed PGD. Univariate analysis of donor characteristics revealed opioid use (P = .049) and death owing to anoxia (P = .021) were associated with PGD. The recipient/donor blood type match AB/A was significantly associated with PGD (P = .031). Time from brain death to aortic cross clamp (TBDACC) of ≥3 and ≥5 days were also found to be associated with PGD (P = .0011 and .0003, respectively). Multivariate analysis confirmed that patients with a time from brain death to aortic cross clamp ≥3 and ≥5 days had lesser odds of developing PGD (odds ratio, 0.098 [P = .0026] and OR, 0.092 [P = .0017], respectively]. CONCLUSIONS: Our study showed that a longer time from brain death to aortic cross clamp was associated with lower odds of developing PGD. Therefore, postponing heart procurement for a few days after brain death seems to be beneficial in preventing PGD.

Desorption dynamics of heavy alkali metal atoms (Rb, Cs) off the surface of helium nanodroplets.

We present a combined ion imaging and density functional theory study of the dynamics of the desorption process of rubidium and cesium atoms off the surface of helium nanodroplets upon excitation of the perturbed 6s and 7s states, respectively. Both experimental and theoretical results are well represented by the pseudodiatomic model for effective masses of the helium droplet in the desorption reaction of meff/mHe ≈ 10 (Rb) and 13 (Cs). Deviations from this model are found for Rb excited to the 6p state. Photoelectron spectra indicate that the dopant-droplet interaction induces relaxation into low-lying electronic states of the desorbed atoms in the course of the ejection process.

Silicones as nonocclusive topical agents.

BACKGROUND/AIMS: Silicone excipients are commonly used ingredients because of their emollient and skin-conditioning effects, and their ability to form uniform, water-resistant, yet permeable films. Based on comparisons with organic materials and conflicting knowledge from silicones used in scar treatment, the misconception still exists that silicone topical excipients are occlusive substances that may block the passive loss of water through the upper skin layers. Therefore, 3 types of common silicone excipients and 3 water-in-(oil-plus-silicone) or W/(O + Si) creams, containing 10% (w/w) of the respective silicones, were investigated as a function of time and compared to petrolatum. METHODS: Transepidermal water loss (TEWL) and skin hydration measurements were carried out after a single topical application on forearm skin of 26 healthy young female volunteers. RESULTS: Both petrolatum and silicones significantly decreased TEWL 15 min after application, but the measurements for the silicones were not significantly different from the untreated control values. The tested silicones did not moisturize the skin. Petrolatum formed an occlusive layer, creating an increase in skin hydration for more than 4 h. The results measured for the W/(O + Si) creams indicated that they moisturized the skin, without any effect on TEWL. CONCLUSION: A clear difference was shown between the skin occlusive properties of petrolatum and the water vapor permeability of the common silicone excipient materials.

Photoionization and imaging spectroscopy of rubidium atoms attached to helium nanodroplets.

Highly excited states of rubidium (Rb) atoms attached to helium (He) nanodroplets are studied by two-photon ionization spectroscopy in combination with electron and ion imaging. We find high yields of RbHe and RbHe(2) exciplexes when exciting to the 4D and 6P bands but not at the 6S band, in accord with a direct formation of exciplexes in binding RbHe pair potentials. Photoion spectra and angular distributions are in good agreement with a pseudodiatomic model for the RbHe(N) complex. Repulsive interactions in the excited states entail fast dissociation followed by ionization of free Rb atoms as well as of RbHe and RbHe(2) exciplexes.

Measuring the effects of topical moisturizers on changes in stratum corneum thickness, water gradients and hydration in vivo.

BACKGROUND: Moisturizers are the most commonly used topically applied product for the treatment of dry skin conditions. They affect many properties and functions of the stratum corneum but some moisturizers have been reported to be detrimental to barrier function. Stratum corneum barrier function is a composite of its total structure and thickness but few studies have taken this into account. As a biosensor, the stratum corneum (SC) will change its structure in response to treatment and a swelling effect has been clearly demonstrated by skin hydration. Recently several moisturizing agents have been shown to have an effect on SC swelling behaviour with conflicting results. However, there is a paucity of data reported for measuring the effects of long-term usage of moisturizers on SC thickness in vivo as, until recently, traditional techniques did not have the resolution to measure the effects of moisturizers on nonpalmoplantar body sites. The development of confocal Raman spectroscopy for use in human subjects provides noninvasive, real-time, in vivo measurement of SC water concentration profiles and we have also used this state of the art equipment to measure the effect of the long-term use of moisturizers on SC thickness for the first time. OBJECTIVES: To validate the use of confocal Raman spectroscopy (CRS) to measure SC thickness and then use it to investigate the short- and long-term effects of moisturizers (one of which is known to improve SC barrier function) on SC thickness, water gradients and hydration. METHODS: Two studies were conducted: (i) to validate the use of CRS for measuring SC thickness through comparison with optical coherence tomography (OCT); and (ii) once validated to use CRS to measure the long-term effects of three commercially available moisturizers (A, B, C) on SC thickness and water gradients, together with total hydration, over a 3-week period (2 weeks of treatment and 1 week regression) and compare the spectroscopy-derived hydration value with instrumentally derived capacitance hydration values. RESULTS: (i) A strong, positive correlation in SC thickness was obtained between CRS and OCT (OCT-derived thickness = 0.96 x CRS-derived thickness, r(2) = 0.93; P <0.0001). OCT was shown, however, to have a lower resolution than CRS in distinguishing SC thickness on thinner nonpalmoplantar body sites. Using the CRS method, differences in SC thickness were readily apparent on different body sites (cheek 12.8 +/- 0.9 microm, volar forearm 18.0 +/- 3.9 microm, leg 22.0 +/- 6.9 microm). (ii) Examining the effects of moisturizers in a blinded, randomized 3-week study in human volunteers (n = 14) demonstrated that only one commercially available formulation (A) changed SC water gradients, thickness and hydration as measured by CRS. These hydration data did not directly correlate with capacitance hydration values. CONCLUSIONS: (i) In vivo CRS was validated as a technique to measure SC thickness on both palmoplantar and, particularly, on nonpalmoplantar skin sites. (ii) Moisturizers improve skin moisturization but in this study only formulation A improved SC thickness, water gradients and hydration as measured by CRS. We hypothesize that this was due to compositional differences between the products. We believe that niacinamide (nicotinamide, vitamin B(3)) is probably contributing significantly to this effect, as it has been proven to increase epidermal lipogenesis and SC barrier function in other studies. These results show that by using CRS, we were able for the first time to determine the effect of moisturizer on multiple SC barrier endpoints including SC thickness, and water content as a function of depth and total SC water content.

Cost-saving analysis of screening colonoscopy in Germany.

BACKGROUND: Screening colonoscopy was introduced into the National Cancer Prevention Program in Germany in 2002. We have explored costs and savings of screening and surveillance colonoscopy to investigate whether the induced savings may compensate for the costs of screening. METHODS: The study design was a model calculation based on data of a large-scale documentation of screening colonoscopy. The costs and savings of screening colonoscopy were evaluated over a defined period of 10 years. Basic data about findings, adverse effects and costs of screening colonoscopy were obtained from a large-scale online registry of 109 989 procedures and from the actual payments of procedures in Germany. Plausible baseline parameter values of the characteristics of screening and surveillance colonoscopy, of adenoma progression and recurrence, and of costs for diagnosis and treatment of colorectal cancer were based on available data. The impact of major model assumptions was evaluated by sensitivity analyses. RESULTS: A programme based on one-time screening colonoscopy could result in net savings over a period of 10 years in Germany due to avoidance of cancer treatment costs compensating for the costs of screening, surveillance and adverse effects. Average net savings from euro 121 to euro 623 per screenee could be achieved according to our model assuming different progression and recurrence rates of adenomas and carcinoma costs from euro 21 820 to euro 40 000. LIMITATIONS: For some major model parameters assumptions had to be derived from the literature. CONCLUSIONS: This analysis based on empirical data from the nationwide screening colonoscopy programme in Germany suggests net savings resulting from colorectal cancer prevention that compensate for the costs of screening and surveillance.

Propofol sedation in outpatient colonoscopy by trained practice nurses supervised by the gastroenterologist: a prospective evaluation of over 3000 cases.

BACKGROUND AND STUDY AIMS: Propofol has several advantages for sedation in endoscopic procedures. Sedation administered by anaesthesiologists is associated with high costs. In this study the safety of propofol sedation administered by trained practice nurses under the supervision of the gastroenterologist in a cohort of outpatients of an ambulatory practice for gastroenterology in Germany is evaluated. METHODS: During a period of 21 months all patients referred to colonoscopy were eligible for this prospective observational study. The familiar CRC risk of the individuals, indication, completeness and results of the colonoscopy were registered together with the dose of propofol used. Propofol was administered by intermittent intravenous bolus titration by trained practice nurses under supervision of the gastroenterologist. Oxygen saturation, heart rate and blood pressure were recorded constantly during the procedure and adverse cardiopulmonary events were monitored by the endoscopy team. A respiratory event was defined as an episode of apnoea or laryngospasm requiring assisted ventilation. 23 % of the patients received supplemental oxygen. RESULTS: A total of 3641 colonoscopies were recorded. 33 individuals were sedated with midazolam and were excluded from the evaluation. 3610 individuals were sedated with propofol (119 +/- 39 mg, mean dose +/- S. D.). 40 % of the procedures were performed as combined gastroscopy and colonoscopy. The cecum was reached in 99 % of the colonoscopies. Respiratory events occurred in five patients (0.14 %). Assisted ventilation in all cases was performed by mask ventilation. Bradycardia (HF < 60/min) and arterial hypotension (RR < 90 mmHg) occurred in 0.5 and 0.3 % of the colonoscopies, respectively, but medical intervention was necessary only in 0.2 % for both types of event. Minor events of hypoxaemia were observed in 51 patients (1.4 %), but only 1/3 of these events occurred in patients supplemented with oxygen. CONCLUSIONS: Propofol can be administered safely for ambulatory colonoscopy by trained practice nurses, with careful monitoring under supervision of the gastroenterologist.

[Results of coloscopy screening in 2005--an Internet-based documentation]. / Ergebnisse der Vorsorge-Koloskopie 2005--Internet-basierte Dokumentation.

BACKGROUND AND OBJECTIVE: In October 2002 screening coloscopy was introduced into the National Cancer Prevention Programme in Germany. The results of an online registry are presented here. METHODS: Data from consecutive screening colonoscopies in the practices of the 280 participating gastroenterologists, performed in asymptomatic subjects, were collected in an online registry. Number and histology of colorectal polyps and carcinomas, complication rates of colonoscopy and polypectomy were registered. Advanced adenoma was defined as an adenoma >10 mm in diameter, with villous or tubulovillous histology, or presence of high-grade dysplasia. RESULTS: A total of 109989 colonoscopies (43% in males) were evaluated from October 2003 to July 2005. Tubular and villous adenomas were found in 16.2% and 3.8%, respectively, whereas invasive cancers were diagnosed in 0.7%. Advanced adenomas amounted to 6.1%.The majority of carcinomas were detected in early stages (UICC stages I and II in 48 and 22 %, respectively). -In most of the polyps immediate polypectomy was carried out. The complication rate was low and no deaths were observed: cardiopulmonary complications occurred in 0.10% of the colonoscopies, bleeding in 0.79% of polypectomies most of which were managed endoscopically (surgery in 0.04% of polypectomies). Perforation occurred in 0.02% of the colonoscopies and 0.10% of polypectomies. CONCLUSIONS: Neoplasias of the colon were detected in about 20% of persons who had taken part in a colonoscopy screening programme: most of the lesions were immediately removed by polypectomy. The high rate of early stages of colorectal cancers detected by screening colonoscopy is an indirect indicator of mortality reduction. In Germany screening colonoscopy has a low risk.

Band erosion with gastric cancer.

Adjustable gastric banding is a well-established procedure for the treatment of morbid obesity. We present a 62-year-old female who experienced the rare complication of intragastric band perforation due to a gastric adenocarcinoma localized at the site of gastric banding, 10 years after insertion of the band.

[Screening colonoscopy among persons 50 to 60 years of age with and without familial risk of colorectal cancer - a prospective multicenter trial]. / Screeningkoloskopie bei Personen zwischen 50 und 60 Jahren mit und ohne familiäres Risiko für Kolonkarzinom - eine prospektive Multizenterstudie.

BACKGROUND: In Germany screening colonoscopy was introduced into the National program on colorectal cancer prevention in Oktober 2002. The prevalence of neoplasia in patients with and without familiar risk was determined together with patient satisfaction with screening colonoscopy. METHODS: Asymptomatic subjects from 50 to 60 years underwent screening colonoscopy and were stratified in two groups with and without familiar risk (first-degree relatives with CRC) in a multicenter trial among German gastroenterologists. Advanced neoplasia was defined as an adenoma at least 1 cm in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. After recovery from sedation all subjects were asked if they would agree to a control colonoscopy and the pain score was recorded on a scale from 0 to 6. RESULTS: A total of 557 subjects (322 at average risk and 235 with familiar risk) underwent screening colonoscopy. The prevalence of advanced neoplasia in subjects without/with familiar risk was not significantly different in persons from 50 to 54 years (9 vs. 15 %) in contrast to persons from 55 to 60 years (10 vs. 22 %, p = 0.004) where the relative risk was doubled. Compared to younger patients, the prevalence of all neoplasia (including small adenomas) was significantly different only for older patients with familiar risk (44 vs. 23 %, p < 0.0001). The mean value of the pain-score was 0.76 + 1.0. Subjects examined without medication had significantly higher pain scores than subjects under medication. Colonoscopy performed under disoprivan resulted in similar pain-scores compared to midazolam at dosages > 5 mg. All patients agreed to a control colonoscopy. CONCLUSION: Screening colonoscopy is an effective and well-accepted method. The high prevalence of advanced neoplasia even in persons from 50 to 54 years suggests that screening should start at the age of 50.

Prospective evaluation of complications in outpatient GI endoscopy: a survey among German gastroenterologists.

BACKGROUND: Although most diagnostic GI endoscopic procedures in Germany are performed on an outpatient basis, there is no large-scale prospective evaluation of complication rates. METHODS: Ninety-four gastroenterologists and internists from all regions of Germany recorded the number of EGD, colonoscopies, and polypectomies performed over a period of 1 year. All serious complications occurring in relation to the procedure, including the use of medication, were recorded in a structured protocol. RESULTS: A total of 110,469 EGDs, 82,416 colonoscopies, and 14,249 polypectomies were evaluated. The "reach-the-cecum-rate" was 97% (median). The overall complication rates for EGD, colonoscopy, and polypectomy were low compared with published data (0.009%, 0.02%, and 0.36%, respectively). The perforation rates were 0.0009%, 0.005%, and 0.06%, respectively, the rates of significant hemorrhage 0.002%, 0.001%, and 0.26%, respectively, and the mortality rates 0.0009%, 0.001%, and 0.007%, respectively. The rates of cardiorespiratory complications associated with EGD and colonoscopy were 0.005% and 0.01%, respectively. The overall complication rate for all procedures (diagnostic and therapeutic) was lower for gastroenterologists (1 per 5155 procedures) than internists (1 per 1539 procedures). Most of the adverse events associated with diagnostic endoscopy were attributable to use of medication. The severity score ranged from 2 to 5 for most of the adverse events occurring as a result of diagnostic procedures and 2 to 50 for polypectomy. The severity sum score per 10,000 procedures was 26 for EGD, 67 for colonoscopy, and 1185 for polypectomy. CONCLUSIONS: Outpatient endoscopy performed in practice settings by German gastroenterologists and internists is safe. The low complication rates may partly be explained by the high degree of experience resulting from the larger numbers of procedures performed relative to the numbers performed by gastroenterologists in hospitals and in other countries.

Primary reactions of sensory rhodopsins.

The first steps in the photocycles of the archaeal photoreceptor proteins sensory rhodopsin (SR) I and II from Halobacterium salinarum and SRII from Natronobacterium pharaonis have been studied by ultrafast pump/probe spectroscopy and steady-state fluorescence spectroscopy. The data for both species of the blue-light receptor SRII suggests that their primary reactions are nearly analogous with a fast decay of the excited electronic state in 300-400 fs and a transition between two red-shifted product states in 4-5 ps. Thus SRII behaves similarly to bacteriorhodopsin. In contrast for SRI at pH 6.0, which absorbs in the orange part of the spectrum, a strongly increased fluorescence quantum yield and a drastically slower and biexponential decay of the excited electronic state occurring on the picosecond time scale (5 ps and 33 ps) is observed. The results suggest that the primary reactions are controlled by the charge distribution in the vicinity of the Schiff base and demonstrate that there is no direct connection between absorption properties and reaction dynamics for the retinal protein family.

[How safe is premedication in ambulatory endoscopy in Germany? A prospective study in gastroenterology specialty practices]. / Wie sicher ist die Prämedikation in der ambulanten Endoskopie in Deutschland? Eine prospektive Untersuchung in gastroenterologischen Fachpraxen.

BACKGROUND: To date there is no prospective large-scale study of the risk of premedication on the complication rate of outpatient gastrointestinal endoscopy in Germany. PATIENTS AND METHODS: In 67 gastroenterological practises in Germany the number of esophagogastroduodenoscopies (EGD) and colonoscopies was recorded from april 1998 until march 1999. All serious complications had to be recorded in a structured protocol. RESULTS: The overall complication rate for EGD (n = 110,469) was low (0.009%) and about two third of the adverse effects were due to premedication (0.006%). The overall complication rate for diagnostic colonoscopy (n = 82,416) was 0.02% and the complication rate associated to premedication was 0.01%. An individual dosage of premedication for EGD and colonoscopy was given by all gastroenterologists. Most of the gastroenterologists applied premedication in 10 to 50 percent of the patients for EGD and in 70 to 100 percent of the patients for colonoscopy. Most of the cardiorespiratory adverse effects in colonoscopy occurred if sedation was performed by combination of benzodiazepines and opioids and in upper gastrointestinal endoscopy with high dosages of diazepam. In 6 of 45 practises disoprivan (propofol) was used for premedication in 2-50 percent of the colonoscopies. Two of four perforations in diagnostic colonoscopy occurred under sedation with disoprivan. CONCLUSIONS: Outpatient gastrointestinal endoscopy performed by German gastroenterologists in a safe. The complication rate is low compared to the international literature and could be further decreased by avoiding a combination of benzodiazepines and opioids for sedation in colonoscopy and high dosages of diazepam in upper gastrointestinal endoscopy.

Helicobacter pylori vacA genotypes and cagA gene in a series of 383 H. pylori-positive patients.

BACKGROUND: Only 10-15% of all patients infected with Helicobacter pylori develop peptic ulcer disease (PUD) or gastric cancer. Apart from immunological factors in the host, virulence determinants of H. pylori such as the vacuolating cytotoxin (VacA) or the cytotoxin-associated protein A (CagA) might represent a predisposition for the development of PUD. METHODS: We studied antral biopsies of 383 H. pylori-positive patients with peptic ulcer disease (PUD) or other H. pylori-related diseases for H. pylori vacA genotypes and the presence of the cagA gene by PCR. RESULTS: VacA genotypes and cagA status could be completely determined in 357 (93.2%) of the patients. In 91 (93.8%) of 97 patients with PUD, the vacA s1 genotype (s1m1, 45; s1m2, 46 patients) was present. The vacA s2m2 genotype was found in only 6 (6.2%) of 97 patients with PUD. In contrast, 180 (75.3%) of 239 patients (s1m1, 89; s1m2, 91 patients) without PUD and without gastric malignancies harbored strains with the vacA s1 genotype. The vacA genotype s2m2 was found in 59 (24.7%) of these patients. The presence of the cagA gene was closely associated with the vacA genotype s1 and found in 124 (88.6%) and in 113 (80.7%) of patients with the s1m1 or s1m2 genotypes, respectively, whereas strains with the genotype s2m2 were almost exclusively cagA negative. CONCLUSION: Most H. pylori strains found in patients with PUD possess the vacA s1 genotype and the cagA gene. Patients with this type of H. pylori strain but without PUD might be at higher risk of developing PUD. In contrast, the risk for PUD might be significantly decreased in those patients who are infected by H. pylori strains with the vacA s2 genotype lacking the cagA gene.

Direct determination of Helicobacter pylori vacA genotypes and cagA gene in gastric biopsies and relationship to gastrointestinal diseases.

OBJECTIVE: Our aim was to detect Helicobacter pylori (H. pylori) from gastric biopsies of 248 patients using a novel, polymerase chain reaction (PCR)-based methodology, which simultaneously facilitates the determination of H. pylori vacA genotypes and cagA gene. METHODS: A simple methodology for sample preparation was established and PCR was performed with primer systems for the 16S rRNA, vacA, and cagA genes, thus circumventing the need to culture H. pylori and to extract DNA from biopsy samples. RESULTS: Infection with H. pylori was detected in 147 (59.3%) of 248 patients. The vacA signal sequence genotype s1 was present in 104 (81.3%) of 128 H. pylori-positive patients, and 24 (18.8%) patients had the genotype s2. The vacA middle region types m1 and m2 were detected in 46 (35.9%) and 79 (61.7%) patients, respectively. The combinations s1/m2 (43%) and s1/m1 (35.9%) were found more frequently than s2/m2 (18.8%). The cagA gene was detected in 75 (72.1%) of 104 H. pylori-positive biopsies with the vacA genotype s1. All 24 biopsies with the type s2 were cagA negative. Strains of the type vacA s1 were found in 97% of H. pylori-positive patients with peptic ulcer disease and were associated with the presence of the cagA gene, whereas 96% of the strains of the type vacA s2 were detected in patients who only had nonulcer dyspepsia. CONCLUSIONS: Using a novel PCR-based methodology, H. pylori 16S rRNA gene, vacA genotypes, and cagA gene can now be rapidly detected directly in gastric biopsies with high accuracy. These data demonstrate that infection with H. pylori strains of the vacA s1 genotype and the cagA gene are more likely to result in peptic ulcer disease. Determination of vacA genotypes and cagA gene may contribute to the potential clinical identification of patients at different levels of risk.

Short-term triple therapy with lansoprazole 30 mg or 60 mg, amoxycillin and clarithromycin to eradicate Helicobacter pylori.

BACKGROUND: We investigated the efficacy of 30 vs. 60 mg lansoprazole daily in a 1-week triple therapy for eradication of Helicobacter pylori in a prospective randomized study. METHODS: Two hundred and fifteen consecutive out-patients with peptic ulcer disease or non-ulcer dyspepsia, in whom H. pylori infection was confirmed by histology and/or a urease biopsy test, were randomly assigned to a 1-week treatment with either 15 mg lansoprazole b.d. (LAC15 group) or 30 mg lansoprazole b.d. (LAC30 group) in combination with 1 g amoxycillin b.d. and 500 mg clarithromycin b.d. RESULTS: Eradication of H. pylori was successful in 87% (per protocol) and 82% (intention-to-treat) of the patients with LAC15 and in 94% (per protocol) and 87% (intention-to-treat) of the patients with LAC30. The difference was not significant. In both treatment groups, all peptic ulcers were healed at the check-up. Adverse effects were seen in 11 patients of the LAC15 group and 10 patients of the LAC30 group: they caused discontinuation of the therapy in four of the LAC15 group and two patients of the LAC 30 group. CONCLUSIONS: A 7-day triple therapy using lansoprazole (LAC15) is an efficient and economical regimen for the eradication of H. pylori.

Detection of colorectal neoplasms by the highly sensitive hemoglobin-haptoglobin complex in feces.

Screening for fecal occult blood by means of guaiac tests has an unsatisfactory sensitivity for the detection of colorectal neoplasms. The immunological determination of human hemoglobin in feces has a higher sensitivity and specificity, but hemoglobin is degraded during its transport through the gastrointestinal tract. We compared the hemoglobin test to a newly developed immuno-chemiluminometric (ILMA) assay for quantifying the hemoglobin-haptoglobin complex in feces which shows high stability against degradation. From each of 621 patients with gastrointestinal complaints before scheduled colonoscopy we collected two 1-ml samples from a single stool; there were no dietary restrictions. The sensitivity for detecting colorectal carcinomas proved 87% with hemoglobin. With the hemoglobin-haptoglobin complex it was 87% at a cutoff level of 1.5 microg/g feces, 83% at 2.0 microg/g feces, and 78% at 2.5 and 3.0 microg/g feces. The sensitivity for detecting large adenomatous polyps was 54% with hemoglobin, 76% with the hemoglobin-haptoglobin complex at a cutoff point of 1.5 microg/g feces, 73% with the hemoglobin-haptoglobin complex at 2.0 and 2.5 microg/g feces, and 65% with the hemoglobin-haptoglobin complex at 3.0 microg/g feces. The optimal cutoff point for the hemoglobin-haptoglobin complex was estimated to be 2.0 microg/g stool. The specificity for hemoglobin (99%) was significantly higher than that for the hemoglobin-haptoglobin complex at 2.0 microg/g feces (96%). Immunological determination of the hemoglobin-haptoglobin complex in feces has a comparable sensitivity as the fecal hemoglobin assay for colorectal carcinomas and a significantly higher sensitivity for adenomatous polyps but a significantly lower specificity. Its use for colorectal cancer prevention is currently being evaluated in a screening study.