Experimental and theoretical 31P and 77Se nuclear magnetic shielding tensors for bis(dineopentoxyphosphorothioyl) diselenide

An intergrown crystal of two phases of bis(dineopentoxyphosphorothioyl) diselenide 1 was investigated by goniometer 31P NMR. From the angular dependence of the chemical shift, the tensors of a triclinic and a monoclinic phase were determined. The principal values sigma11, sigma22, and sigma33, of the absolute nuclear magnetic shielding tensors for the triclinic phase are 134.1, 227.2, and 375.5 ppm and for the monoclinic phase are 132.4, 227.8, and 374.2 ppm, respectively. In both cases, the principal axis 3 of the 31P tensor is directed nearly along the P=S bond and the principal axis 2 is nearly perpendicular to the S=P-Se plane. Calculations of the 31P and 77Se nuclear magnetic shielding tensors were performed for molecules of both phases of 1 and for model compounds by the sum-over-states density functional perturbation theory IGLO method. The rms distances between calculated and experimental 31P NMR icosahedral tensor values sigma(j) (j = 1, ..., 6) amount to 17-21 ppm. The calculated and experimental orientations of the 31P principal axes show a maximum difference of 5 degrees and rms distances of 3.2 and 3.3 degrees. For the principal value sigma33 of the selenium shielding tensor the agreement between calculated and experimental values is satisfactory, but the calculated values sigma11 and sigma22 are distinctly too small. Calculations for a model compound in which the methyl groups of the neopentoxy residue are substituted by protons lead practically to the same results.

Detection of an epileptic mirror focus after oral application of clonidine

We report detection of an epileptic mirror focus approximately 2 h after administration of oral clonidine 150 micrograms in a patient with an intractable complex partial seizure disorder. The specific epileptic activity was documented by electroencephalographic (EEG) and magnetoencephalographic (MEG) recordings. The case illustrates a possible role of clonidine in facilitating specific discharges.

Successful treatment of pulmonary Mycobacterium xenopi infection in a natural killer cell-deficient patient with clarithromycin, rifabutin, and sparfloxacin

Isolation of Mycobacterium xenopi from the respiratory tract may indicate pneumonia, often clinically indistinguishable from tuberculosis. Resistance to the classic antituberculous drugs renders the treatment of these infections problematic. We report on a case of cavernous pneumonia caused by M. xenopi in a 36-year-old male with natural killer cell deficiency but without severe immunodeficiency. He was successfully treated with a novel triple-drug combination comprising clarithromycin, sparfloxacin, and rifabutin. An impressive subsequent regression of pathological pulmonary changes was observed, and mycobacteria could no longer be detected. The therapeutic potential of clarithromycin and sparfloxacin in the treatment of M. xenopi infections is discussed.

Contig assembly of bacterial artificial chromosome clones through multiplexed fluorescence-labeled fingerprinting

A rapid multiplexed fingerprinting method has been developed for bacterial artificial chromosome (BAC) contig assembly. Defined subsets of BAC DNA fragments that result from digestion by three paired restriction endonucleases are labeled with unique fluorescent F-ddATP for each subset. Lists of the labeled fragment size are generated by an ABI 377 DNA sequencer and the GeneScan analysis software and then processed by an assembly program, FPC (Fingerprinted Contigs), to produce contig maps. Data obtained from the multiplexed labeling permit detection of smaller overlaps than is observed when data from a single double-digest are analyzed. The method has been tested on 98 BACs from chromosome 22 regions where large-scale sequencing is under way and also through simulation, using randomly generated BAC clones derived from existing DNA sequence data. In each case, contig assembly results demonstrated the advantages of multiplexed fingerprinting.

Dynamic changes in electrogram morphology at functional lines of block in reentrant circuits during ventricular tachycardia in the infarcted canine heart: a new method to localize reentrant circuits from electrogram features using adaptive template matching

INTRODUCTION

Fractionated, low-amplitude or long-duration electrograms have limited specificity for locating reentrant circuits causing ventricular tachycardia (VT). In this study a new method is described, adaptive template matching (ATM), based on the quantification of beat-to-beat changes in electrograms, for locating functional reentrant circuits that are relatively stable and cause monomorphic VT.

METHODS AND RESULTS

Monomorphic VTs were induced in 4-day-old infarcted canine hearts by programmed stimulation and reentrant circuits mapped in the epicardial border zone with a 196 or 312 bipolar electrode array. For ATM analysis, a template electrogram from each electrode, during an early cycle, was matched with all subsequent (input) electrograms at the same site by weighting the inputs of amplitude, duration, average baseline, and phase lag. The mean square error (MSE) between template and input was the criterion used to adapt the weights, and was also a measure of changes in electrogram shape that occur from cycle to cycle. The variance of each of the weighting parameters at all electrode sites were plotted on a representation of the electrode array, and the location of the functional lines of block bounding the central common pathway of reentrant circuits with figure-of-eight characteristics, overlaid on the ATM map. Peaks of high variance were found to be coincident with functional lines of block during all tachycardia episodes.

CONCLUSION

Specific beat-to-beat changes in electrograms occur at functional lines of block in reentrant circuits that can be quantified by ATM analysis, suggesting that these regions might be located without activation mapping. The method might be useful to guide ablation catheter position.

Location of diastolic potentials in reentrant circuits causing sustained ventricular tachycardia in the infarcted canine heart: relationship to predicted critical ablation sites

BACKGROUND

The complete reentrant circuit for ablation of reentrant ventricular tachycardia (VT) in humans can rarely be localized by mapping. As a result, surrogate markers, such as diastolic electrical activity, subsequently confirmed by entrainment, have been used. However, ablation at those sites has had variable efficacy. The reasons for this variability are not clear.

METHODS AND RESULTS

We correlated activation maps of reentrant circuits in the epicardial border zone of 4-day old infarcted dog hearts with the corresponding ECGs for 45 VTs to determine the regions of the reentrant circuits activated during diastole. In VTs with a figure-8 reentrant pattern, the center point of the central common pathway, the part of the circuit critical for the maintenance of reentry, was activated in early diastole in 32 of 35 VTs (91.4%), in late diastole in 1 (2.9%), and in systole in 2 (5.7%). Regions outside the circuit were rarely activated in diastole. In 10 VTs, the reentrant circuit was characterized by a single reentrant loop. In these circuits, no one region was predicted to be critical for maintenance of reentry, and a segment of the circuits was activated during diastole. However, regions peripheral to the circuit were also activated during diastole.

CONCLUSIONS

The pattern of reentrant activation determines the specificity of diastolic activity for locating critical sites for ablation of VT.

Clonidine- and methohexital-induced epileptiform discharges detected by magnetoencephalography (MEG) in patients with localization-related epilepsies

PURPOSE

During presurgical evaluation, 14 patients with medically intractable focal epilepsies underwent magnetoencephalographic (MEG) recordings to localize the epileptogenic focus. To increase the number of epileptiform discharges required for MEG analysis, methohexital a short-acting barbiturate that is known to activate epileptiform activity, was used. Additionally, we investigated the spike-provoking properties of clonidine in comparison to methohexital.

METHODS

After oral premedication with clonidine, short-lasting anesthesia was provided by intravenously administered methohexital. The number and location of epileptiform MEG discharges were assessed after clonidine premedication and during methohexital anesthesia. Results were compared with baseline MEG recordings.

RESULTS

Methohexital increased the frequency of focal epileptiform discharges in eight of 13 patients (one of the 14 patients did not receive methohexital after premedication with clonidine). Additionally, premedication with clonidine was found to increase focal epileptiform discharges in nine of 14 patients. When compared with baseline MEG recordings, recordings after treatment with both clonidine premedication and methohexital anesthesia showed a significant increase in the total number of epileptiform signals and the number of spikes contributing to MEG source localizations.

CONCLUSIONS

This study confirms the selective proconvulsant effects of methohexital on the epileptogenic focus as suggested previously by EEG and electrocorticogram (ECoG) investigations. Additionally, our data establish for the first time that clonidine increases epileptiform activity in patients with seizure disorders. These results indicate that clonidine is suited as an activating agent for the localization of epileptogenic foci by means of MEG. This effect of clonidine on specific epileptic activity also indicates that clonidine should be used with caution as an antihypertensive drug in patients with seizure disorders.

Clonidine and methohexital-induced epileptic magnetoencephalographic discharges in patients with focal epilepsies

PURPOSE

During presurgical evaluation, 14 patients with medically intractable focal epilepsies underwent magnetoencephalographic (MEG) recordings for focus localization. To increase the number of epileptic discharges required for MEG analysis, we administered methohexital (MHT), a short-acting barbiturate known to provoke epileptic activity. We also investigated the spike-provoking properties of clonidine in comparison with MHT.

METHODS

Patients were briefly anesthetized with intravenously administered MHT after being premedicated orally with clonidine. Numbers and locations of epileptic MEG discharges were assessed after clonidine premedication as well as during MHT anesthesia. Results were compared with baseline MEG recordings.

RESULTS

MHT increased the frequency of focal epileptic discharges in 8 of 13 patients ( of the 14 patients did not receive MHT after premedication with clonidine). Premedication with clonidine also increased focal epileptic discharges in 9 of 14 patients. The numbers of epileptic signals and numbers of spikes contributing to MEG source localizations were significantly increased in MEG recordings under both treatment conditions (clonidine premedication and MHT anesthesia) as compared with baseline MEG recordings.

CONCLUSIONS

Our results confirmed the selective proconvulsive effects of MHT on the epileptic focus, as previously suggested by EEG and electrocorticographic (ECoG) investigations. However, our present data establish for the first time that clonidine increases epileptic activity in patients with seizure disorders and indicate that clonidine is suitable as an activating agent for localization of epileptogenic foci by MEG. This effect of clonidine on specific epileptic activity also indicates that specific care must be taken when clonidine is used as an antihypertensive drug in patients with seizure disorders.

Neisseria meningitidis serogroup B peritonitis associated with continuous ambulatory peritoneal dialysis

A case of Neisseria meningitidis peritonitis in a 41-year-old female undergoing continuous ambulatory peritoneal dialysis for end-stage renal failure due to insulin-dependent diabetes mellitus is reported. The bacterial strain was serosubtyped as 4:P1.15, a rarely encountered type. Surprisingly, the minimal inhibitory concentration of vancomycin for the isolate was low (16 mg/l). This may have contributed to the complete recovery of the patient.

Deletion mapping by FISH with BACs in patients with partial monosomy 22q13

Patients with deletions in 22q13 are known to have phenotypic features that include normal or accelerated growth, large hands and feet, hypotonia, delayed psychomotor development and mild facial dysmorphism. To date, very few cases have been investigated by detailed molecular genetic analysis. We have analyzed three new patients with terminal deletions in 22q. We compared the cytogenetic observations with molecular data assessed by fluorescence in situ hybridization and an array of characterized bacterial artificial chromosome recombinants. The shortest region of deletion overlap is localized in 22q13.2-qter distal to the marker D22S94, but the telomeric repeat in the deleted chromosome appears to remain intact. When parental alleles were investigated in two of the three patients, the aberrant homolog was found to be of paternal origin in both cases. Although the deleted region still spans >20 cM, molecular analysis of additional patients and screening for new genes might help in elucidating candidate genes connected with the dysmorphisms defined by deletions of 22q13.

Classical and molecular cytogenetic methods in diagnosis of a rare translocation t(3;21)

We report the characterization by traditional cytogenetic methods and fluorescence in situ hybridization (FISH) of a rare balanced reciprocal translocation t(3;21) in a male spouse connected with several miscarriages. G- and C-banding analysis of the male karyotype was suggestive of breakpoints in chromosomal bands 3q11.1 and 21p11.1. Multicolor-FISH analysis using chromosome-specific alpha-satellite probes in combination with a locus-specific bacterial artificial chromosome (BAC) from 21q22.3 allowed us both to identify the origin of centromeres in the derivative chromosomes and to establish centromere-telomere orientation of the translocated chromosome 21 segment. Characterization of the translocated chromosomes by FISH analysis permitted describing the exact karyotype of the carrier as: 46,XY,-3,-21,+der(3)(21qterO21q11. 2::3p11.2O cenO3qter),+der(21)(3pterO3p11.2::21q11.2OcenO21pte r).

[Quality and quality assurance, a European problem]

The problem of quality and quality assurance for the free exchange of blood and blood products in Europe is discussed. The background of all discussion of quality is the categorical theory of Aristoteles. The philosophical basis is described. The fundamental law of the daily work of a blood center has to be a philosophy of quality which depends on the sociodemographic situation in the region. This basic varies from country to country in Europe. The importance of the supranational bodies in Europe is mentioned. The weightness of the Code of Ethics is discussed. Virus safety, purity and validity of blood and blood products are described as parameters of the quality aspects. Finally it is confirmed that a well running blood program is a multicategorical problem.

[Comparison ov anti-HCV tests of the first and second generation and suggestions for a re-entry program]

After following up approximately 200,000 blood donors with 1st- and 2nd-generation anti-HCV tests the authors suggest: 1) to neglect earlier 1st-generation-positive anti-HCV results when the donor is negative in 2nd-generation ELISAs; 2) after a donation positive in a 2nd-generation test the following donation must not be used even if it is negative; a third, negative donation can be used; 3) a donor with two different donations positive in 2nd-generation ELISAs should be excluded from the donor pool.

Non-specific and specific anti-HCV results correlated to age, sex, transaminase, rhesus blood group and follow-up in blood donors

Second generation enzyme immunoassays (EIA-2) for antibodies to hepatitis C virus (anti-HCV) have a higher specificity and sensitivity than first generation enzyme immunoassays (EIA-1). We studied how many anti-HCV-positive blood donors were missed by the EIA-1, how many were false positive, how false-positive donors should be dealt with and how the results of the EIA-2 correlate to demographic data and serum alanine aminotransferase (ALT) level. A total of 208, 544 northern German blood donors, not preselected for anti-HCV negativity, were tested for anti-HCV with EIA-2 and, if repeatability reactive (rr), were retested with a licensed supplementary test (RIBA-2). 0.43% of the donors were EIA-2 rr, but only 0.12% of women and 0.09% of men were RIBA-2 positive. RIBA-2 positivity rates were very low in donors 18 to 27 years old (0.03% and 0.05%) and rose with age in women but not in men. Infected women were significantly more often Rhesus-negative than men. The rate of unspecifically positive EIA-2 results (entirely negative in RIBA-2) increased with age in both sexes and did not correlate with ALT. The ALT distribution was age-dependent with a different pattern for men and women. Confirmation of EIA-2 results with RIBA was rare when ALT was low and frequent when ALT was high. ALT screening before introduction of Anti-HCV detected one out of six infected donors. To exclude this one infectious donation, 46 uninfected donations had to be excluded in addition. Only 8% of the then RIBA-2-positive donors were not detected by EIA-1. Apparent seroconversions in EIA-2 are usually not specific; only 1 out of 66 apparent seroconversions could be confirmed by RIBA-2 suggesting recent HCV infection. 0.15% of the donor population showed an inconsistent EIA-2 pattern during follow-up. We conclude that donors should not be excluded from further donations, even on the basis of multiple EIA-1 positive results or on the basis of only one EIA-2 positive donation. Anti-D-immunoglobulin prophylaxis may have been a source of infection in some Rhesus-negative women. ALT screening should not be discontinued because recent HCV infection can be detected earlier by ALT than by anti-HCV, but exclusion limits should be elevated to increase specificity and limit unnecessary exclusion of donations.

Mechanisms for spontaneous termination of monomorphic, sustained ventricular tachycardia: results of activation mapping of reentrant circuits in the epicardial border zone of subacute canine infarcts

OBJECTIVES

The objective of this study was to determine why sustained ventricular tachycardias (VT) sometimes stop without outside intervention.

BACKGROUND

Sustained, monomorphic VT in patients with ischemic heart disease is often caused by reentrant excitation. These tachycardias can degenerate into rapid polymorphic rhythms or occasionally terminate spontaneously.

METHODS

Sustained VT was induced by programmed stimulation in dog hearts 4 to 5 days after ligation of the left anterior descending coronary artery. Activation in reentrant circuits in the epicardial border zone of the infarct was mapped using 192 to 312 bipolar electrodes.

RESULTS

Spontaneous termination of sustained VT always occurred when the reentrant wave front blocked in the central common pathway in reentrant circuits with a figure-of-eight configuration. Two major patterns of termination were identified from activation maps of the circuits that were not distinguishable from each other on the surface electrocardiogram: 1) Abrupt termination was not preceded by any change in the pattern of activation or cycle length. It could occur at different locations within the central common pathway, was not related to the directions of the muscle fiber orientation and was not caused by a short excitable gap. 2) Termination caused by premature activation (after a short cycle) either resulted from shortening of the functional lines of block around which the reentrant impulse circulated or was caused by wave fronts originating outside the reentrant circuit. In only one episode were oscillations of cycle length associated with termination.

CONCLUSIONS

The mechanisms for termination of reentry in functional circuits causing VT are different from those in anatomic circuits where oscillatory behavior precedes termination.

Reduced frequency of severe hypoglycemia and coma in well-controlled IDDM patients treated with insulin lispro. The Benelux-UK Insulin Lispro Study Group

OBJECTIVE

Several studies have suggested that use of the short-acting insulin analog, insulin lispro, in multiple injection therapy may reduce the risk of hypoglycemia in comparison with regular insulin. This effect might be more pronounced in well-controlled patients, since intensive treatment of IDDM increases the rate of severe hypoglycemic events. This study evaluated the effects of insulin lispro on glycemic control and hypoglycemia rates in well-controlled IDDM patients.

RESEARCH DESIGN AND METHODS

This was an open, randomized, 6-month crossover study of 199 IDDM patients. Glycemic control was evaluated by HbA1c, home blood glucose measurements, and rate and timing of hypoglycemic events. At the end of the study, patients completed an evaluation form regarding therapy-related quality of life.

RESULTS

HbA1c remained constant at approximately 7.3% throughout the study. Meal-related glucose excursions were significantly lower with insulin lispro compared with regular insulin (mean -0.8 +/- 1.7 vs. 1.1 +/- 1.6 mmol/l, P < 0.001), as was the within-day variability (M value 27.7 +/- 19.7 vs. 30.2 +/- 23.1, P = 0.007). The incidence of severe hypoglycemic events (58 vs. 36, P = 0.037) including coma (16 vs. 3, P = 0.004) was significantly lower with insulin lispro than with regular insulin. Patients felt that insulin lispro increased flexibility and freedom of lifestyle.

CONCLUSIONS

In well-controlled IDDM patients, insulin lispro is associated with a lower risk of severe hypoglycemia and coma.

A mechanical model of human spinal motion segments

A modular mechanical model of the spine was developed which can be adapted to approximate the mechanical properties of various spinal levels and pathologic conditions in single- or multi-segmental forms. The characteristics of the model were compared with those of human L4-5 specimens in flexion and extension, axial rotation and lateral bending. The model showed comparable ranges of motion to those of human specimens in all directions and likewise was characterized by increasing stiffness with increasing load as well as hysteresis. This model can be used as a standard for the comparison of different spine testers. As a substitute for cadaveric specimens in implant testing, these models provide the advantages of availability, consistent properties, and adaptability, and avoid the risks associated with handling human tissue.

A cell strain system for small homogeneous strain applications

A cell culture system has been developed that enables application of well characterized, homogeneously distributed cyclic strains to monolayer cell cultures. Optically clear silicone culture dishes atop Plexiglas base plates are deformed by four-point bending of flexible silicone culture wells driven in user specified strain cycle patterns using computer controlled electromagnetic linear actuators. Cyclic mechano-transduction can be induced in amplitudes of 0 to 3000 mustrain, in frequencies of 0 to 30 Hz and in any specified strain cycle pattern. The cell culture system, which contains six simultaneously driven culture wells, has been mechanically characterized by holographic interferometry, laser displacement sensor recordings of the dish surfaces, strain gauge monitoring of the base plates, and finite element modeling of the dishes on the base plates. The standard deviation of the strain amplitudes among the six simultaneously stimulated culture wells is less than 5%. The cell culture system allows accurate generation of small magnitudes of well characterized, homogeneous strain, easy handling of the culture wells, flexible setting of cyclic strain pattern parameters, simultaneous stimulation of 6 culture wells, and light microscopic observation of the cell cultures.

Renal artery stenosis: evaluation with colour duplex ultrasonography

BACKGROUND

Detection of renal artery stenoses (RAS) by means of duplex Doppler ultrasound with direct scanning of the main renal arteries is subject to numerous limitations. Using semiquantitative analysis of the Doppler curve, which can be recorded from intrarenal arteries, it is possible to detect RAS unaffected by the problems of direct Doppler scanning of the renal arteries.

METHODS

Both angiography of the renal arteries and colour duplex ultrasonography (US) of the intrarenal vessels (interlobar arteries) were performed in 214 patients (53.2 +/- 14.1 years) with severe arterial hypertension. Angiography was used as 'gold standard' in the diagnosis of RAS and the Doppler results were compared with the subsequent findings on angiography. At angiography, the reduction of diameter > 70% was assessed as haemodynamically effective RAS. For the duplex Doppler diagnosis of RAS the following parameters were calculated: (a) resistive index (RI) of each kidney, and (b) side-to-side differences of the resistive indices (delta RI) between the right and left kidney.

RESULTS

Angiography demonstrated 59 RAS (> 70%) in 53 patients, including six with bilateral RAS. By means of duplex US we found a significant difference of RI between kidneys with RAS (0.48 +/- 0.11) and without RAS (0.63 +/- 0.08; P < 0.001). In addition, a significant difference of the delta RI was noted in patients with RAS (24.4% +/- 12.5%) and the controls without RAS (3.6% +/- 2.7%). Using a combination of both RI and delta RI, threshold values of RI = 0.45 resp. delta RI = 8% yields a sensitivity of 92.5% and a specificity of 95.7% in the detection of haemodynamically effective RAS.

CONCLUSIONS

Colour duplex US with calculation of the RI and delta RI of intrarenal arteries is a valuable non-invasive test assessing the haemodynamic effects of a RAS. Low costs and safety support the use of the Doppler technique in screening for renovascular disease.

Molecular definition of a novel human galectin which is immunogenic in patients with Hodgkin's disease

Using autologous serum for the immunoscreening of a cDNA expression library derived from tissue involved by Hodgkin's disease, a new 36-kDa protein with the characteristics of galectins (S-type lectins) was detected. Sequence analysis of the cDNA clone HOM-HD-21 revealed two homologous motifs known as lectin domains with galactoside binding capacity. The two domains are linked by a stretch of about 30 amino acid residues and share a sequence homology of 39%. While the N-terminal lectin domain shows merely moderate homologies with known galectins, the C-terminal lectin domain is highly homologous to rat galectin-5 with an amino acid sequence identity of 70%. We ruled out mutations of the tumor-derived transcript by sequence comparison with the respective cDNA cloned from normal peripheral blood leukocytes. Recombinant protein expressed in Chinese hamster ovary cells was purified from lysates by lactose and galactose affinity chromatography, proving the galactoside binding capacity of this new galectin. Northern blot analysis revealed an expression spectrum restricted to peripheral blood leukocytes and lymphatic tissues. In accordance with the nomenclature of known galectins, we suggest to designate this novel galactoside binding protein galectin-9.

Cosmid-derived transcripts and sequence tags mapped to three subregions of human chromosome 22

Fifty cosmids from the ICRF, London, and Lawrence Livermore Laboratory, California, human chromosome 22 cosmid libraries were isolated, regionally assigned and tested for their ability to detect repeats or single copy sequences. The search resulted in nine cosmids containing repetitive motifs from the pericentric region of chromosome 22. An additional 19 cosmids, that detected single copy sequences in the long arm of chromosome 22q: 7 in the region 22q11.2-q13.1 and 12 in 22q13.1-qter, were mapped more precisely by fluorescence in situ hybridization. Three out of these 19 recombinants displayed restriction fragments containing (CA)n repeats, were subcloned and sequenced. One cosmid, representing a region coding for an ubiquitous 300-bp transcript, is localized 600 kb from PDGFB, and four cosmids contained sequences surrounding the ARSA gene at 22q13.3. Presently, long range physical maps, that may be useful for analysing structural alterations of chromosome 22q13, are being constructed from these additional, regionally assigned markers from chromosome 22q13 employing both existing cosmid and new bacterial artificial chromosome (BAC) libraries.

Activation of transcription factor AP-2 mediates UVA radiation- and singlet oxygen-induced expression of the human intercellular adhesion molecule 1 gene

UVA radiation is the major component of the UV solar spectrum that reaches the earth, and the therapeutic application of UVA radiation is increasing in medicine. Analysis of the cellular effects of UVA radiation has revealed that exposure of human cells to UVA radiation at physiological doses leads to increased gene expression and that this UVA response is primarily mediated through the generation of singlet oxygen. In this study, the mechanisms by which UVA radiation induces transcriptional activation of the human intercellular adhesion molecule 1 (ICAM-1) were examined. UVA radiation was capable of inducing activation of the human ICAM-1 promoter and increasing ICAM-1 mRNA and protein expression. These UVA radiation effects were inhibited by singlet oxygen quenchers, augmented by enhancement of singlet oxygen life-time, and mimicked in unirradiated cells by a singlet oxygen-generating system. UVA radiation as well as singlet oxygen-induced ICAM-1 promoter activation required activation of the transcription factor AP-2. Accordingly, both stimuli activated AP-2, and deletion of the putative AP-2-binding site abrogated ICAM-1 promoter activation in this system. This study identified the AP-2 site as the UVA radiation- and singlet oxygen-responsive element of the human ICAM-1 gene. The capacity of UVA radiation and/or singlet oxygen to induce human gene expression through activation of AP-2 indicates a previously unrecognized role of this transcription factor in the mammalian stress response.

[Acute pulmonary syndrome and cavernous pulmonary tuberculosis in a patient with sickle cell disease]

HISTORY AND CLINICAL FINDINGS

A 17-year-old girl from Zaire was admitted to hospital with fever, cough, dyspnoea and severe chest pain. In addition to marked anaemia (haemoglobin 6.6 g/dl) she was known to have cavitary/exudative pulmonary tuberculosis (PTb) with bilateral basal infiltrations.

INVESTIGATIONS

Blood gas analysis indicated partial respiratory failure (pO2 55 mm Hg, pCO2 36 mm Hg). Blood smear under air exclusion showed erythrocyte sickling. Haemoglobin electrophoresis demonstrated 92.7% HbS and thus confirmed sickle cell anaemia. A small spleen on sonography and the presence of Howell-Jolly bodies were interpreted as signs of functional asplenia. Microbiological and radiological tests confirmed exudative-cavitary PTb.

TREATMENT AND COURSE

The findings were interpreted as due to an acute chest syndrome, caused by sickle cell thrombi in the pulmonary blood vessels, precipitated by the PTb. Transfusion of two units of erythrocyte concentrates led to improvement of the chest pain and the respiratory failure within a few hours. The PTb was successfully treated without any complications.

CONCLUSION

Acute chest syndrome is a vascular occlusive complication of sickle cell disease, pulmonary tuberculosis precipitating the development of this acute condition. Administration of erythrocyte concentrate rapidly improves the signs and symptoms.

Cloning of contiguous genomic fragments from human chromosome 21 harbouring three trefoil peptide genes

A group of small peptides with a typical cysteine-rich domain (termed trefoil motif or P-domain) is abundantly expressed at mucosal surfaces of specific normal and neoplastic tissues. Their association with the maintenance of surface integrity was suggested. The first known human trefoil peptide (pS2) was isolated from breast cancer cells (MCF7). Its oestrogen-inducible gene, and the human homologue to the porcine spasmolytic peptide gene (hSP/SML1) appear synchronously expressed in healthy stomach mucosa and several carcinomas of the gastrointestinal tract. Both genes were shown to be localised at 21q22.3. A new trefoil peptide from human intestinal mucosa (hITF/hP1.B) and its gene were described recently. By using suitable oligonucleotide primers and PCR and isolating large (110-250 kb) genomic recombinants cloned in the bacterial artificial chromosome (BAC) system, we present a genomic region from chromosome band 21q22.3 cloned in contiguous sequences and encoding all three members of human P-domain/trefoil peptides proving a physical linkage of all three trefoil peptide genes. Such genomic sequences will provide useful experimental material for analysis of gene regulation, for gene modification experiments and for establishing transgenic cells or animals.

Ca2+ triggers massive exocytosis in Chinese hamster ovary cells

We have tracked the cell surface area of CHO cells by measuring the membrane capacitance, Cm. An increase in cytosolic [Ca2+], [Ca2+]i, increased the cell surface area by 20-30%. At micromolar [Ca2+]i the increase occurred in minutes, while at 20 microM or higher [Ca2+]i it occurred in seconds and was transient. GTPgammaS caused a 3% increase even at 0.1 microM [Ca2+]i. We conclude that CHO cells, previously thought capable only of constitutive exocytosis, can perform Ca2+-triggered exocytosis that is both massive and rapid. Ca2+-triggered exocytosis was also observed in 3T3 fibroblasts. Our findings add evidence to the view that Ca induces exocytosis in cells other than known secretory cells.

[Foot stress simulator for biomechanical in vitro studies of lower leg segments]

In this paper we describe a foot-loading simulator that permits in vitro studies on human lower leg and foot specimens. The specimens are fixed in a jig and loaded axially with the aid of a pneumatic cylinder. The resulting transfer of forces through the ankle joint complex and Chopart's articulation (line) can be demonstrated on a pressure-sensitive film. Plantar pressure measurements obtained in patients or normal subjects can be used to ensure the comparability of in vivo and in vitro measurements. The supporting platform can be tilted in such a manner as to provide a range of foot positions up to 20 degrees in plantar- or dorsiflexion, eversion or inversion. The system is used for investigating the effects on the intra-articular pressures and plantar pressure patterns of physiological muscle activity and pathological conditions following fracture of the calcaneum or damage to the lateral ligament. By way of an example, the effects of muscle forces on plantar pressure distribution are presented.

Framework for a physical map of the human 22q13 region using bacterial artificial chromosomes (BACs)

Detailed physical maps of entire chromosomes based on combined genetic, cytogenetic, and structural information are essential components for positional cloning and genomic sequencing. Despite the wealth of genetic information of the known diseases in the chromosome 22q13, the construction of a detailed physical map of the terminal region is difficult due to the sparsity of the genetic markers. We present here a map of bacterial artificial chromosome (BAC) contigs that cover a number of genetic loci in the 22q13 region. One hundred thirty-six BACs with an average insert size of 140 kb are assembled into 35 contigs defined by 64 markers in 22q13-qter. Twenty-three anonymous markers are now linked to the previously mapped genetic anchor points.

Human trefoil peptides: genomic structure in 21q22.3 and coordinated expression

Trefoil peptides are small secretory proteins characterized by three intrachain disulfide bonds forming the trefoil motif or P-domain. They are abundantly expressed on mucosal surfaces, especially of the gastrointestinal tract. In pathological conditions such as ulcers, metaplasia and neoplasia, their expression is upregulated. Three human trefoil peptides have been described: the estrogen-inducible pS2 protein, the spasmolytic protein and the intestinal trefoil factor. Recently, their role in the maintenance of surface integrity and ulcer healing was discussed. We already mapped the corresponding three genes (BCEI), SML1, TFF3) to the same genomic region (21q22.3). In this paper, we show that the three genes are clustered in a tandemly orientated fashion within 50 kb on a bacterial artificial chromosome (BAC) recombinant. This cluster is located adjacent to D21S19 and the locus order is cen-D21S212-TFF3-SML1-BCEI-D21S19-tel, whereas transcription of all three genes is directed towards the centromere. The gene structure of SML1 exhibits four exons, two of which encode the two separate trefoil motifs. TFF3 and BCEI, both containing one trefoil motif, are composed of three exons each, suggesting gene duplication and exon-shuffling events during evolution. The 5'-flanking region of SML1 was compared to the corresponding region of other trefoil genes. Two motifs with identical sequence and positions are shared between SML1 and BCEI, thus presenting possible targets for stomach-specific gene regulation. Two other motifs are shared within all known human and rat trefoil genes, suggesting a coordinated regulation and/or a common locus-controlling region. Using RT-PCR, a change in the pattern of trefoil gene expression is detected in tissue samples from normal gastric mucosa, hyperplastic polyps, gastric cancer, and gastric cancer cell lines, respectively.

A third P-domain peptide gene (TFF3), human intestinal trefoil factor, maps to 21q22.3

Small peptides displaying a cysteine-rich module (termed P-domain or trefoil motif) form a recently increasing group of peptides abundantly expressed at mucosal surfaces of specific tissues and are associated with the maintenance of surface integrity. The estrogen-inducible pS2 gene (BCEI) and the human homolog to the porcine spasmolytic peptide (hsP) gene (SML1) appear synchronously expressed in healthy stomach mucosa and several carcinomas of the gastrointestinal tract. Both genes were shown to be located at 21q22.3. A new trefoil peptide from human intestinal mucosa (hITF/hP1.B) and its gene (TFF3) were described recently. By PCR analysis of a somatic cell hybrid panel and FISH using two large genomic recombinants (110 kb, 210 kb) cloned in the Bacterial Artificial Chromosome (BAC) system, we show that this gene coding for the new member of human P-domain/trefoil peptides also maps to chromosome region 21q22.3 suggesting a physical linkage of all three trefoil peptide genes.

Human neoplasms elicit multiple specific immune responses in the autologous host

Expression of cDNA libraries from human melanoma, renal cancer, astrocytoma, and Hodgkin disease in Escherichia coli and screening for clones reactive with high-titer IgG antibodies in autologous patient serum lead to the discovery of at least four antigens with a restricted expression pattern in each tumor. Besides antigens known to elicit T-cell responses, such as MAGE-1 and tyrosinase, numerous additional antigens that were overexpressed or specifically expressed in tumors of the same type were identified. Sequence analyses suggest that many of these molecules, besides being the target of a specific immune response, might be of relevance for tumor growth. Antibodies to a given antigen were usually confined to patients with the same tumor type. The unexpected frequency of human tumor antigens, which can be readily defined at the molecular level by the serological analysis of autologous tumor cDNA expression cloning, indicates that human neoplasms elicit multiple specific immune responses in the autologous host and provides diagnostic and therapeutic approaches to human cancer.

Age, sex and transaminase dependency of specific and nonspecific results from enzyme immunoassays for antibodies to hepatitis C virus and follow-up of blood donors

BACKGROUND

Second-generation enzyme immunoassays (EIA-2) for antibodies to hepatitis C virus (anti-HCV) have an improved specificity and sensitivity compared to first-generation enzyme immunoassays (EIA-1). Therefore the question arises how many anti-HCV-positive blood donors were missed by the EIA-1, how many were false positive, how false-positive donors should be dealt with and how the results of the EIA-2 correlate with demographic data and surrogate testing for serum alanine aminotransferase (ALT).

MATERIAL AND METHODS

A total of 208,544 individual North German blood donors not preselected for anti-HCV negativity were tested for anti-HCV with EIA-2 and, if repeatedly reactive (rr), with a licensed supplementary test (RIBA-2).

RESULTS

Overall, 0.43% of the donors were EIA-2 rr, but only 0.12% of women and 0.09% of men were RIBA-2 positive. RIBA-2 positivity rates were very low in donors 18 to 27 years old (0.03% and 0.05%) and clearly rose with age in women but not in men. The rate of unspecifically positive EIA-2 results (entirely negative in RIBA-2) rose with age in both sexes and did not correlate with ALT. The ALT distribution was age dependent with a completely different pattern for men and women. Anti-HCV positivity was strongly correlated with ALT albeit on a very low level: more than 97% of donors with strongly elevated ALT were anti-HCV negative. Follow-up and comparison of EIA-1, EIA-2 and RIBA-2 results for the subsequent donations showed that only 8% of now RIBA-2-positive donors were not detected by EIA-1. Apparent seroconversions in EIA-2 are usually not specific: only one out of 66 apparent seroconversions could be confirmed by RIBA-2. 0.15% of the donor population showed an inconsistent EIA-2 pattern during follow-up.

CONCLUSIONS

We therefore suggest that donors should not be excluded from further donations on the basis even of multiple EIA-1 positive results or on the basis of only one EIA-2-positive donation. The value of ALT screening for transfusion safety should be reconsidered.

Modulation of neuronal calcium channels by arachidonic acid and related substances

Low-voltage-activated (l-v-a) and high-voltage-activated (h-v-a) Ca2+ currents (ICa) were recorded in whole-cell voltage clamped NG108-15 neuroblastoma x glioma hybrid cells. We studied the effects of arachidonic acid (AA), oleic acid, myristic acid and of the positively charged compounds tetradecyltrimethylammonium (C14TMA) and sphingosine. At pulse potentials > -20 mV, AA (25-100 microM) decreased l-v-a and h-v-a ICa equally. The decrease developed slowly and became continually stronger with increasing time of application. It was accompanied by a small negative shift and a slight flattening of the activation and inactivation curves of the l-v-a ICa. The shift of the activation curve manifested itself in a small increase of l-v-a ICa at pulse potentials < -30 mV. The effects were only partly reversible. The AA effect was not prevented by 50 microM 5, 8, 11, 14-eicosatetraynoic acid, an inhibitor of the AA metabolism, and not mimicked by 0.1-1 microM phorbol 12, 13-dibutyrate, an activator of protein kinase C. Probably, AA directly affects the channel protein or its lipid environment. Oleic and myristic acid acted similarly to AA but were much less effective. The positively charged compounds C14TMA and sphingosine had a different effect: They shifted the activation curve of l-v-a ICa in the positive direction and suppressed l-v-a more than h-v-a ICa; their effect reached a steady-state within 5-10 min and was readily reversible. C14TMA blocked l-v-a ICa with an IC50 of 4.2 microM while sphingosine was less potent.

[Prevalence of goiter in the Aachen area. Ultrasound volumetry of the thyroid gland of 1,336 adults in an endemic goiter region]

AIM

The aim of the study was to assess the prevalence of thyroid enlargement by ultrasonic volume measurements.

RESULTS

1336 adults living in the iodine-deficient area of Aachen, West Germany (760 females, 576 males, mean age: 54.05 +/- 16.09 years) were included in the investigation. The ultrasonic examination was carried out in patients who did not suffer from thyroid disease at the time of study.

RESULTS

The thyroid volume was age-dependent and varied from 13.3 +/- 10.4 ml in patients < 21 years to 29.9 +/- 24.3 ml in patients > 70 years. The prevalence of thyroid enlargement ranged from 14.3% in young people to 51.3% in the elderly. There was no difference in the volumes of the left and right thyroid lobe. The prevalence of thyroid enlargement was higher in females compared to males (p < 0.05). Retrosternal thyroid mass was detected in 25% of all patients > 70 years.

CONCLUSION

There is evidence of a high prevalence of thyroid enlargement in iodine-deficient areas.

Model experiments on squid axons and NG108-15 mouse neuroblastoma x rat glioma hybrid cells

Three types of ionic current essentially determine the firing pattern of nerve cells: the persistent Na+ current, the M current and the low-voltage-activated Ca(2)+ current. The present article summarizes recent experiments concerned with the basic properties of these currents. Keynes and Meves (Proc R Soc Lond B (1993) 253, 61-68) studied the persistent or steady-state Na+ current on dialysed squid axons and measured the probability of channel opening both for the peak and the steady-state Na+ current (PF(peak) and PF(ss)) as a function of voltage. Whereas PF(peak) starts to rise at -50 mV and reaches a maximum at +40 to +50 mV, PF(ss) only begins to rise appreciably at around 0 mV and is still increasing at +100 mV. This differs from observations on vertebrate excitable tissues where the persistent Na+ current tums on in the threshold region and saturates at around 0 mV. Schmitt and Meves (Pflugers Arch (1993) 425, 134-139) recorded M current, a non-inactivating K+ current, from NGI08-15 neuroblastoma x glioma hybrid cells, voltage-clamped in the whole-cell mode, and studied the effects of phorbol 12,13-dibutyrate (PDB), an activator of protein kinase C (PKC), and arachidonic acid (AA). PDB and AA both decreased I(M), the effective concentrations being 0.1-1 mu M and 5-25 mu M, respectively; while the PDB effect was regularly observed, the M current depression by AA was highly variable from cell to cell. The PKC 19-31 peptide, an effective inhibitor of PKC, in a concentration of 1 muM almost totally prevented the effects of PDB and AA on M current, suggesting that both are mediated by PKC. Schmitt and Meves (Pflugers Arch (1994a) 426, Suppl R 59) measured low-voltage-activated (l-v-a) and high-voltage-activated (h-v-a) Ca2+ currents on NG108-15 cells and investigated the effect of AA and PDB on both types of current. At pulse potentials > -20 mV, AA (25-100 mu M) decreased 1-v-a and h-v-a I(Ca). The decrease was accompanied by a small negative shift and a slight flattening of the activation and inactivation curves of the l-v-a I(Ca). The AA effect was not prevented by 50 mu M eicosa-5,8,11,14-tetraynoic acid (ETYA), an inhibitor of AA metabolism, or PKC 19-31 peptide and not mimicked by 0.1-1 mu M PDB. Probably, AA acts directly on the channel protein or its lipid environment. The physiological relevance of these three sets of observations is briefly discussed.

Telomere length variation in normal and malignant human tissues

Tissue and tumor specific length variation of telomere (TTAGGG)n repeats was studied in DNAs from various normal and malignant tissues. DNA was isolated from bone marrow and blood cells, malignant tissues, and established tumor cell lines. Nonisotopic Southern hybridization revealed a reduction of telomere repeat arrays in 14 of the 35 tumors analyzed. However, other cases (60%) showed no reduction, or even an increase, in telomeric length. Our finding of elongated telomere stretches in several tumors of different origin compared with normal tissue is in contrast to previous reports describing a general shortening of terminal repeat length in colorectal cancer and neuroblastoma. We tentatively conclude that there is no general tendency to telomere reduction in malignant tissues.