Quantification of murine IFN-gamma mRNA and protein expression: impact of real-time kinetic RT-PCR using SYBR green I dye

Reliable quantification of cytokine mRNA expression is an important technique for analyzing immune responses. Up until now, little to no information has been available as to whether different mRNA quantification techniques lead to similar results. Recently, real time quantitative reverse transcriptase (RT)-PCR using SYBR Green I as a double stranded DNA specific dye has been introduced. This novel method enables simple and rapid measurement of PCR product accumulation during the log-linear reaction phase and obviates the need for expensive hybridization probes. Here, we analyzed murine gamma interferon (IFN)-gamma mRNA expression in splenocytes by this technique in comparison to semiquantitative noncompetitive RT-PCR, Northern blot analysis, and ELISA after stimulation of the cells with interleukin (IL)-12, IL-18 and a combination of both cytokines. The results clearly show that all of the techniques detect differences in the IFN-gamma gene expression induced by these distinctive stimuli qualitatively exactly in the same order. However, real-time kinetic RT-PCR offers several advantages, notably its high sensitivity that allows the detection of basal IFN-gamma mRNA expression in unstimulated samples. In addition it provides the lowest interassay variability of all techniques investigated. Finally, the gene expression measured by this method eliminates any post-PCR manipulations because the PCR product identification can be easily performed by melting curve analysis.

An algorithm for statistical alignment of sequences related by a binary tree

An algorithm is presented that allows the calculation of the probability of a set of sequences related by a binary tree that has evolved according to the Thorne-Kishino-Felsenstein model (1991) for a fixed set of parameters. There are two ideas underlying this algorithm. Firstly, a markov chain is defined that generates ancestral sequences and their alignment at two neighboring nodes in a tree. Secondly, a stochastic walk on the binary tree, that defines a markov chain generating ancestral sequences and their alignment at the internal nodes in the tree is described. The running time of this algorithm is O(l2 kappa), where l is the geometric average of the sequence lengths and kappa the number of sequences--leaves at the binary tree. This could be improved to O(l kappa).

Comparative efficacy of clarithromycin modified-release and clarithromycin immediate-release formulations in the treatment of lower respiratory tract infection

BACKGROUND

A modified-release (MR) formulation of clarithromycin, distinct from the extended-release formulation, has recently been developed and has efficacy and tolerability similar to standard immediate-release (IR) clarithromycin, with the advantage of once-daily dosing.

OBJECTIVE

The purpose of this study was to compare the efficacy (as measured by relief of clinical symptoms and eradication of specific pathogens) and tolerability of clarithromycin MR 500 mg administered once daily versus clarithromycin IR 250 mg administered twice daily for 5 days.

METHODS

In this randomized, double-blind (with matching placebo), parallel-group. multicenter, controlled trial, patients with lower respiratory tract infection were randomized to 1 of 2 treatment regimens: clarithromycin MR 500 mg once daily plus clarithromycin IR 250 mg placebo twice daily or clarithromycin IR 250 mg BID plus clarithromycin MR 500 mg placebo once daily.

RESULTS

Statistically equivalent clinical cure and success rates, overall symptomatic improvement, and bacteriologic responses were achieved with both treatments. In the clarithromycin MR group, the clinical cure rate was 72.5% (87/120), and the clinical success rate (cure plus symptomatic improvement) was 97.5% (117/120). Of the 124 patients treated with clarithromycin IR 250 mg BID, 98 (79.0%) achieved a clinical cure, and 120 (96.8%) achieved clinical success. There were no statistically significant between-group differences in clinical cure or success rates. More than 85% of patients in both study groups experienced improvement in dyspnea, cough, wheezing, chest discomfort, fatigue, and fever, and the visual appearance of sputum: these symptoms resolved completely in the majority of patients. Bacteriologic response (efficacy against specific pathogens), which was assessed as an objective efficacy criterion, was assessable for 40 patients treated with clarithromycin MR and 49 patients treated with clarithromycin IR. Bacteriologic eradication of the pretreatment target pathogen was achieved in 95.0% (38/40) of assessable patients treated with clarithromycin MR 500 mg once daily and 91.8% (45/49) of patients treated with clarithromycin IR 250 mg BID. Treatment-related adverse events were mild to moderate in all cases. Nausea (n = 9), diarrhea (n = 6), abdominal pain (n = 5), and gastric pain (n = 3) were the only study drug-related adverse events reported by > or = 1 patient in each treatment arm. Diarrhea was reported only in the clarithromycin IR group (n = 6) (P = 0.029 vs clarithromycin MR).

CONCLUSIONS

Clarithromycin MR 500 mg administered once daily for 5 days is as effective and well tolerated as the IR formulation, with the advantage of once-daily dosing and fewer episodes of diarrhea.

Are there specific disabilities of number processing in adolescent patients with Anorexia nervosa? Evidence from clinical and neuropsychological data when compared to morphometric measures from magnetic resonance imaging

The cerebral effect of the loss of body weight in Anorexia nervosa (A.n.)--the so-called 'pseudoatrophy'-- is well known and confirmed by several neuroimaging studies. Another subject of intensive research has been whether A.n. leads to specific cognitive impairments, especially of intelligence. However, there are no previous studies on the relations between the cerebral changes, intelligence performance, and disorders of number processing in adolescent patients with A.n. We examined n = 18 inpatients with A.n. (means at admission: age 14.5 years, SD 1.59; BMI 14.9, SD 1.36), diagnosed according to ICD-10 criteria at three different timepoints: at admission to treatment (T1), with 50 % restoration of their normal weight (T2), and with normal weight (T3). At each timepoint, a cerebral MRI scan was obtained. Based on the MRI we determined the volume of the external and internal cerebrospinal fluid cavities, fissures of Sylvius, the surface of mesencephalon and pons, and surface and length of the Corpus callosum. At T1 and T3, a neuropsychological examination was conducted including tests of the general fluid ability and general cristallized ability of intelligence (CFT-20), as well as tests of vocabulary and number processing. The same instruments were given to a group of matched controls (means: age 15.8 years, SD 1.57; BMI 20.5, SD 2.3) at one timepoint. We could show a significant volume difference of the lateral ventricles and the fissure of Sylvius between patients at T, and controls, which abaded with the patient's weight restoration. But a significant surface deficit of the mesencephalon, and less pronounced in the pons, persisted to T3 in patients when compared to controls, suggesting a selectivity of the cerebral changes in A.n. The neuropsychological examinations revealed significant changes in test performance for both the general intelligence test and number processing. At T1 the number processing performance was significantly lower in patients when compared to controls. However, when the patients had restored their normal body weight, we found 2.02 % with a 'severe disorder of arithmetic skills' and 4.45 % with a 'functional disorder of arithmetic skills'. This combined prevalence of 6.47 % of patients with a subnormal arithmetic performance is analogous to that in the normal population.

The specific disorder of arithmetic skills. Prevalence studies in a rural and an urban population sample and their clinico-neuropsychological validation

There is an often noted lack of research in the field of disorders of arithmetic skills. The present study assessed the prevalence in both an urban and a rural population sample of German schoolchildren, using standardized academic achievement tests. Eight school classes of third graders in each area were examined (n = 181,182; respectively). We found that 6.6 % (n = 12) of the rural and 6.59 % (n = 12) of the urban school children performed significantly worse in arithmetic than in their spelling tests. Since the diagnostic criteria for the Specific disorder of arithmetical skills and their significance are widely discussed, we attempted in a second step of the study to validate the diagnosis of the Specific disorder of arithmetical skills from a neuropsychological and medical viewpoint. For the validation we assessed clinical data, imaging and neurophysiologic studies as well as a neuropsychological test battery. Nine and five of the children, respectively, were available for this further evaluation. Although the majority of these probands (n = 10) had distinct arithmetic deficits, only three of them met the full diagnostic criteria of the ICD-10 for a Specific disorder of arithmetic skills. In a last step, we compared the data of both studies. Our data strongly support a thorough cliniconeurological, neuropsychological and academic assessment of students with a suspected Specific disorder of arithmetic skills. The current diagnostic criteria should be reconsidered and possibly modified towards a more psychopathologic definition. We stress the need that the condition becomes better known among all professions concerned with the care of children, as difficulties with acquiring arithmetic skills should be detected and approached appropriately as early as possible. The imperative demand of future empiric research is emphasized.

Neuropsychological differentiation of subnormal arithmetic abilities in children

For the neuropsychological diagnosis of a Specific disorder of arithmetic skills the standard is defined worldwide by the diagnostic guidelines of the two major classification systems of psychiatric disorders, the ICD- 10 and the DSM-IV, both of which use the discrepancy criterion as the key feature of the diagnosis. It becomes clear that following such guidelines can only mean an extensive diagnostic assessment of patients with subnormal arithmetic abilities, including the social and previous medical history followed by the exclusion of a present disorder or disability, often necessitating laboratory, neuroimaging and neurophysiological tests. In the neuropsychological diagnosis of a Specific disorder of arithmetical skills we found a stepwise approach including previously obtained test results to be most practical and economical. The assessment instruments such as intelligence tests, neuropsychological test batteries, academic achievement tests, specific neuropsychological tests, test batteries for arithmetic abilities or error analysis are discussed. An overview of case studies in the literature is given; however, the overwhelming majority of case reports on patients with arithmetic disabilities are casuistics of adult patients with an acquired loss of arithmetic abilities. The importance of a differentiated neuropsychological diagnosis is demonstrated by four of our own cases: of borderline deficient intelligence, a combined disorder of academic skills, congenital brain dysfunction, and a specific disorder of arithmetic skills. Especially the new quality in assessing arithmetic abilities with the NUCALC battery is demonstrated; diagnostic and therapeutic consequences are discussed.

Consequences of recombination on traditional phylogenetic analysis

We investigate the shape of a phylogenetic tree reconstructed from sequences evolving under the coalescent with recombination. The motivation is that evolutionary inferences are often made from phylogenetic trees reconstructed from population data even though recombination may well occur (mtDNA or viral sequences) or does occur (nuclear sequences). We investigate the size and direction of biases when a single tree is reconstructed ignoring recombination. Standard software (PHYLIP) was used to construct the best phylogenetic tree from sequences simulated under the coalescent with recombination. With recombination present, the length of terminal branches and the total branch length are larger, and the time to the most recent common ancestor smaller, than for a tree reconstructed from sequences evolving with no recombination. The effects are pronounced even for small levels of recombination that may not be immediately detectable in a data set. The phylogenies when recombination is present superficially resemble phylogenies for sequences from an exponentially growing population. However, exponential growth has a different effect on statistics such as Tajima's D. Furthermore, ignoring recombination leads to a large overestimation of the substitution rate heterogeneity and the loss of the molecular clock. These results are discussed in relation to viral and mtDNA data sets.

Statistical alignment: computational properties, homology testing and goodness-of-fit

The model of insertions and deletions in biological sequences, first formulated by Thorne, Kishino, and Felsenstein in 1991 (the TKF91 model), provides a basis for performing alignment within a statistical framework. Here we investigate this model.Firstly, we show how to accelerate the statistical alignment algorithms several orders of magnitude. The main innovations are to confine likelihood calculations to a band close to the similarity based alignment, to get good initial guesses of the evolutionary parameters and to apply an efficient numerical optimisation algorithm for finding the maximum likelihood estimate. In addition, the recursions originally presented by Thorne, Kishino and Felsenstein can be simplified. Two proteins, about 1500 amino acids long, can be analysed with this method in less than five seconds on a fast desktop computer, which makes this method practical for actual data analysis.Secondly, we propose a new homology test based on this model, where homology means that an ancestor to a sequence pair can be found finitely far back in time. This test has statistical advantages relative to the traditional shuffle test for proteins.Finally, we describe a goodness-of-fit test, that allows testing the proposed insertion-deletion (indel) process inherent to this model and find that real sequences (here globins) probably experience indels longer than one, contrary to what is assumed by the model.

The coalescent with gene conversion

In this article we develop a coalescent model with intralocus gene conversion. The distribution of the tract length is geometric in concordance with results published in the literature. We derive a simulation scheme and deduce a number of analytical results for this coalescent with gene conversion. We compare patterns of variability in samples simulated according to the coalescent with recombination with similar patterns simulated according to the coalescent with gene conversion alone. Further, an expression for the expected number of topology shifts in a sample of present-day sequences caused by gene conversion events is derived.

Interferon consensus sequence binding protein confers resistance against Yersinia enterocolitica

Interferon consensus sequence binding protein (ICSBP)-deficient mice display enhanced susceptibility to intracellular pathogens. At least two distinct immunoregulatory defects are responsible for this phenotype. First, diminished production of reactive oxygen intermediates in macrophages results in impaired intracellular killing of microorganisms. Second, defective early interleukin-12 (IL-12) production upon microbial challenge leads to a failure in gamma interferon (IFN-gamma) induction and subsequently in T helper 1 immune responses. Here, we investigated the role of ICSBP in resistance against the extracellular bacterium Yersinia enterocolitica. ICSBP(-/-) mice failed to produce IL-12 and IFN-gamma, but also IL-4, after Yersinia challenge. In addition, granuloma formation was highly disturbed in infected ICSBP(-/-) mice, leading to multiple necrotic abscesses in affected organs. Consequently, ICSBP(-/-) mice rapidly succumbed to acute Yersinia infection. In vitro treatment of spleen cells from ICSBP(-/-) mice with recombinant IL-12 (rIL-12) or rIL-18 in combination with a second stimulus resulted in IFN-gamma induction. In experimental therapy of infected ICSBP(-/-) mice, we observed that administration of rIL-12 induced IFN-gamma production which was associated with improved resistance to Yersinia. In contrast, treatment with rIL-18 failed to enhance endogenous IFN-gamma production but nevertheless reduced bacterial burden in ICSBP(-/-) mice. Although cytokine therapy with rIL-12 or rIL-18 ameliorated the course of Yersinia infection in ICSBP(-/-) mice, both cytokines failed to completely restore impaired immunity. Taken together, the results indicate that the transcription factor ICSBP is essential for efficient host immune defense against Yersinia. These results are important for understanding the complex host immune responses in bacterial infections.

Predictors of cognitive test patterns in autism families

In a case-control study of cognitive performance, tests of intelligence, reading, spelling, and pragmatic language were administered to the parents and siblings of 90 community-ascertained probands with autism (AU group) and to the parents and siblings of 40 similarly ascertained probands with trisomy 21 Down syndrome (DS group). The two samples were comparable for age and parents' education; both groups were well-educated and had above-average intelligence. AU parents scored slightly but significantly lower on the WAIS-R Full Scale and Performance IQ, on two subtests (Picture Arrangement and Picture Completion), and on the Word Attack Test (reading nonsense words) from the Woodcock-Johnson battery. There were no differences between AU and DS siblings. As in earlier studies, AU parents, more often than DS parents, reported a history of early language-related cognitive difficulties; we were not able to replicate this in siblings. AU parents who reported such difficulties scored significantly lower on Verbal IQ, spelling, and the nonsense reading test. AU parents without a history of early language-related cognitive difficulties often had a Verbal IQ that exceeded Performance IQ by more than one standard deviation. AU siblings with early language-related difficulties had similar findings: lower Verbal IQ, poorer spelling, and poorer reading scores, compared to AU siblings without such a history. Parents with a positive history also scored worse on a measure of pragmatic language,the Pragmatic Rating Scale, but not on measures of social-related components of the broader autism phenotype. We propose that cognitive differences in a subset of autism family members are manifestations of the language-related component of the broader autism phenotype, and separate from the social-related component. This is consistent with the hypothesis that there are several genes that may interact to cause autism which segregate independently and have distinguishable manifestations in family members. The hypothesis would be further supported by finding different patterns of genetic loci linked to autism in families where one or both parents has language difficulties.

Recombination as a point process along sequences

Histories of sequences in the coalescent model with recombination can be simulated using an algorithm that takes as input a sample of extant sequences. The algorithm traces the history of the sequences going back in time, encountering recombinations and coalescence (duplications) until the ancestral material is located on one sequence for homologous positions in the present sequences. Here an alternative algorithm is formulated not as going back in time and operating on sequences, but by moving spatially along the sequences, updating the history of the sequences as recombination points are encountered. This algorithm focuses on spatial aspects of the coalescent with recombination rather than on temporal aspects as is the case of familiar algorithms. Mathematical results related to spatial aspects of the coalescent with recombination are derived.

RNA secondary structure prediction using stochastic context-free grammars and evolutionary history

MOTIVATION

Many computerized methods for RNA secondary structure prediction have been developed. Few of these methods, however, employ an evolutionary model, thus relevant information is often left out from the structure determination. This paper introduces a method which incorporates evolutionary history into RNA secondary structure prediction. The method reported here is based on stochastic context-free grammars (SCFGs) to give a prior probability distribution of structures.

RESULTS

The phylogenetic tree relating the sequences can be found by maximum likelihood (ML) estimation from the model introduced here. The tree is shown to reveal information about the structure, due to mutation patterns. The inclusion of a prior distribution of RNA structures ensures good structure predictions even for a small number of related sequences. Prediction is carried out using maximum a posteriori estimation (MAP) estimation in a Bayesian approach. For small sequence sets, the method performs very well compared to current automated methods.

The ancestry of a sample of sequences subject to recombination

In this article we discuss the ancestry of sequences sampled from the coalescent with recombination with constant population size 2N. We have studied a number of variables based on simulations of sample histories, and some analytical results are derived. Consider the leftmost nucleotide in the sequences. We show that the number of nucleotides sharing a most recent common ancestor (MRCA) with the leftmost nucleotide is approximately log(1 + 4N Lr)/4Nr when two sequences are compared, where L denotes sequence length in nucleotides, and r the recombination rate between any two neighboring nucleotides per generation. For larger samples, the number of nucleotides sharing MRCA with the leftmost nucleotide decreases and becomes almost independent of 4N Lr. Further, we show that a segment of the sequences sharing a MRCA consists in mean of 3/8Nr nucleotides, when two sequences are compared, and that this decreases toward 1/4Nr nucleotides when the whole population is sampled. A measure of the correlation between the genealogies of two nucleotides on two sequences is introduced. We show analytically that even when the nucleotides are separated by a large genetic distance, but share MRCA, the genealogies will show only little correlation. This is surprising, because the time until the two nucleotides shared MRCA is reciprocal to the genetic distance. Using simulations, the mean time until all positions in the sample have found a MRCA increases logarithmically with increasing sequence length and is considerably lower than a theoretically predicted upper bound. On the basis of simulations, it turns out that important properties of the coalescent with recombinations of the whole population are reflected in the properties of a sample of low size.

Combining many multiple alignments in one improved alignment

MOTIVATION

The fact that the multiple sequence alignment problem is of high complexity has led to many different heuristic algorithms attempting to find a solution in what would be considered a reasonable amount of computation time and space. Very few of these heuristics produce results that are guaranteed always to lie within a certain distance of an optimal solution (given a measure of quality, e.g. parsimony). Most practical heuristics cannot guarantee this, but nevertheless perform well for certain cases. An alignment, obtained with one of these heuristics and with a bad overall score, is not unusable though, it might contain important information on how substrings should be aligned. This paper presents a method that extracts qualitatively good sub-alignments from a set of multiple alignments and combines these into a new, often improved alignment. The algorithm is implemented as a variant of the traditional dynamic programming technique.

RESULTS

An implementation of ComAlign (the algorithm that combines multiple alignments) has been run on several sets of artificially generated sequences and a set of 5S RNA sequences. To assess the quality of the alignments obtained, the results have been compared with the output of MSA 2.1 (Gupta et al., Proceedings of the Sixth Annual Symposium on Combinatorial Pattern Matching, 1995; Kececioglu et al., http://www.techfak.uni-bielefeld. de/bcd/Lectures/kececioglu.html, 1995). In all cases, ComAlign was able to produce a solution with a score comparable to the solution obtained by MSA. The results also show that ComAlign actually does combine parts from different alignments and not just select the best of them.

AVAILABILITY

The C source code (a Smalltalk version is being worked on) of ComAlign and the other programs that have been implemented in this context are free and available on WWW (http://www.daimi.au.dk/ õcaprani).

CONTACT

klaus@bucka-lassen.dk; jotun@pop.bio.au.dk;ocaprani@daimi.au.dk

Meanings of state hospital nursing. I: Facing challenges

The purpose of this study was to describe the meaning of work for nurses employed in two state psychiatric hospitals. Nurses at both hospitals participated in designing and carrying out the research. In Phase I, nurses described situations in which they had been observers or participant observers and the way that they understood what was occurring in the situations described. The data from these descriptions were analyzed in collaboration with small groups of nurse co-investigators at each hospital. In Phase II, patterns of meaning identified in Phase I were checked and further refined based on focus groups and interviews with nurses at both hospitals. The interrelated dilemmas faced by nurses are discussed as (1) challenges in clinical decision making, (2) challenges regarding personal control, and (3) challenges of maintaining professional standards. Ways of meeting these challenges, coping, and making meaning are discussed in a companion article, "Meanings of State Hospital Nursing II: Coping and Making Meaning".

[Eating before of an unselected student population of the 7th to 10th grade in a Berlin school]

In 1990 a study of 32 girls and 44 boys in Grades 7 to 10 in a former "East Berlin" school in the borough of Prenzlauer Berg was carried out in continuation of an "East-West Berlin Study on Eating Disorders in Adolescents" which we had initiated in the mid-eighties. The Eating Attitudes Test (EAT), Eating Disorder Inventory (EDI), State of Comfort Scale (SCS) were used in a one-step study design together with complementary clinical and sociodemographic data, including body weight, height and BMI. On the whole, all students were well aware of their own body measurements and had definite ideas about their ideal body weight. Boys were less sure about their real weight, while girls showed some insecurity in defining their ideal weight. Regardless of weight parameters, girls were more strongly preoccupied with issues specific to eating disorders, such as dissatisfaction with their own body, the quest for a slim figure and diet. They were more severely affected by perceptions of insufficiency. 44% of all girls and 4% of the boys said they had problems with their body weight. These students' intensive preoccupation with issues specific to eating disorders was dependent on their actual body weight. They exhibited more clearly pronounced psychological characteristics of eating disorders. Eating-related and psychological characteristics of eating disorders were significantly more pronounced in girls with irregular menstruation. The correlation between irregular menstruation and individually perceived weight problems was significant. These results are discussed in greater detail with due consideration of the need for understanding the specific dynamics of eating attitudes in the general population.

[Short-term triple therapy with pantoprazole, amoxicillin and metronidazole in Helicobacter pylori infection]

BACKGROUND

The present study was conducted to investigate the efficacy and tolerability of a 7-day treatment with pantoprazole, amoxicillin and metronidazole for the eradication of Helicobacter pylori (H. pylori) infection.

PATIENTS AND METHODS

Fifty patients (26 male, 24 female, age 18 to 86, mean 54 years) with an active duodenal (n = 25) or gastric ulcer (n = 25) were recruited into the study, 48 patients being H. pylori positive at the study start. Patients were treated with pantoprazole (40 mg bid), amoxicillin (1 g bid) and metronidazole (500 mg bid) for 7 days and for another 21 days with pantoprazole (40 mg/od). Four weeks after the end of study medications the patients were re-examined endoscopically and their H. pylori status was re-assessed using urease test, histology and 13C-urea-breath test.

RESULTS

In 39 of 48 intention to treat patients, H. pylori infection was cured, according to 81% (95%-CI = 67 to 91%). In the per protocol population in 35 of 41 patients H. pylori was eradicated, which results in an eradication rate of 85% (95%-CI = 71 to 94%). Ulcer healing was endoscopically confirmed in 45 of 48 patients (94%; 95%-CI = 83 to 99%) after 8 weeks. Six of 50 patients (12%) reported mild to moderate probable side-effects of the study medication. Cure of the infection was associated with a distinct reduction of the gastritis grade and activity.

CONCLUSION

A 7-day triple therapy using pantoprazole, amoxicillin and metronidazole is an effective and cost-effective alternative to regimens including clarithromycin for the treatment of H. pylori infection.

On the number of ancestors to a DNA sequence

If homologous sequences in a population are not subject to recombination, they can all be traced back to one ancestral sequence. However, the rest of our genome is subject to recombination and will be spread out on a series of individuals. The distribution of ancestral material to an extant chromosome is here investigated by the coalescent with recombination, and the results are discussed relative to humans. In an ancestral population of actual size 1.3 million a minority of <6.4% will carry material ancestral to any present human. The estimated actual population size can be even higher, 5 million, reducing the percentage to 1.7%.

Measurements of a nonlinear refractive index with a single laser pulse

We demonstrate a theoretical model and the experimental proof of a new method for n(2) measurements using single pulses. The advantage of the method is fast measurement, a simple setup, and independence from small nonlinear absorptions and thermal effects. We report on first n(2) measurements with the new technique on carbon disulfide, toluene, and a polymer dissolved in toluene to demonstrate the measurement of positive and negative third-order nonlinearities. We achieved a sensitivity of greater than lambda/200 phase-front distortion using picosecond Nd:YLF laser pulses. The given theory shows that attainment of higher sensitivities is possible.

[Urticaria vasculitis]

Fifteen cases with suspected urticarial vasculitis which were seen during the last ten years at the Department of Dermatology in Hamburg were reviewed. The cases were reevaluated after strict formulation of criteria for vasculitis (fibrin in and around small vessels, leukocytoclasis of neutrophilic granulocytes, extravasation of erythrocytes) and discussed in the context of the international literature on urticarial vasculitis. The conclusion of our study is that urticarial vasculitis is often overdiagnosed clinically if persistent urticarial lesions occur that show some erythematous changes or a hint of hemorrhage. Furthermore, urticarial vasculitis is often overdiagnosed histopathologically because some cases of urticaria were found that presented with heavy infiltration of small vessel walls with neutrophilic granulocytes. In these cases extravasation of erythrocytes, fibrin in and around vessels and leukocytoclasis is always absent. In summary urticarial vasculitis seems to be a variation of leukocytoclastic vasculitis with less extravasation of erythrocytes and not, as frequently stated, and entity of its own.