Self-assembly of a peptide amphiphile containing L-carnosine and its mixtures with a multilamellar vesicle forming lipid.

The self-assembly of the peptide amphiphile (PA) hexadecyl-(ß-alanine-histidine) is examined in aqueous solution, along with its mixtures with multilamellar vesicles formed by DPPC (dipalmitoyl phosphatidylcholine). This PA, denoted C(16)-ßAH, contains a dipeptide headgroup corresponding to the bioactive molecule L-carnosine. It is found to self-assemble into nanotapes based on stacked layers of molecules. Bilayers are found to coexist with monolayers in which the PA molecules pack with alternating up-down arrangement so that the headgroups decorate both surfaces. The bilayers become dehydrated as PA concentration increases and the number of layers in the stack decreases to produce ultrathin nanotapes comprised of 2-3 bilayers. Addition of the PA to DPPC multilamellar vesicles leads to a transition to well-defined unilamellar vesicles. The unique ability to modulate the stacking of this PA as a function of concentration, combined with its ability to induce a multilamellar to unilamellar thinning of DPPC vesicles, may be useful in biomaterials applications where the presentation of the peptide function at the surface of self-assembled nanostructures is crucial.

Calcaneal ultrasound attenuation and vitamin-D-receptor genotypes in celiac disease.

BACKGROUND: Osteopenia is common in patients with celiac disease and is believed to result from malnutrition. Osteoporosis in otherwise healthy individuals is related to genetically determined polymorphisms within the vitamin-D-receptor (VDR) gene. We hypothesized that in celiac patients particular genes of the VDR enhance the susceptibility for malnutrition-associated low-bone density. METHODS: We determined allelic frequencies within the VDR gene by restriction fragment length polymorphism analysis in 92 patients with celiac disease (age, 15-83 years). Thirty-eight patients were on a gluten-free diet; 54 patients did not adhere to a diet. The determined VDR polymorphisms in 111 unrelated newborns served as controls. Osteopenia was determined by means of ultrasound measurements of the calcaneus (n = 78). Bone turnover was estimated by osteocalcin determination (n = 60). RESULTS: There was no difference in the frequency of the VDR gene polymorphisms in patients with celiac disease compared with controls. Adjusted ultrasound measures of the calcaneus were low in 47% of patients, but there was no difference of the VDR gene frequencies in these patients compared with those with normal ultrasound results or controls. Bone turnover was higher in patients without a gluten-free diet (P = 0.02). Again, there was no association with any particular VDR gene. CONCLUSIONS: Patients with celiac disease frequently have osteopenia, which is not related to any of the determined genes within the VDR.

Conflicting results of ileoscopy and small bowel double-contrast barium examination in patients with Crohn's disease.

BACKGROUND AND STUDY AIMS: Ileoscopy has become a routine procedure for the diagnosis of Crohn's disease of the terminal ileum. The aim of this study was to compare the diagnostic accuracy of small bowel barium examination with that of ileoscopy. PATIENTS AND METHODS: In a retrospective study the two methods were compared in 55 patients with Crohn's disease. First, routine radiology reports and second, reevaluation of the small bowel barium study by gastrointestinal radiologists with scoring of examination quality were compared with the results of ileoscopy. RESULTS: Using routine radiology reports, 66% sensitivity and 82% specificity were reached for inflammatory changes of the terminal ileum by small bowel barium study. Sensitivity and specificity increased to 68% and 91% with double reading by experienced radiologists. Disagreement between endoscopic and radiologic results changed from 31% to 27% and were mainly because of false-negative barium studies. Sensitivity and specificity of barium studies were influenced by the quality of the examination with a sensitivity of 91% and specificity of 100% when the quality was good. CONCLUSIONS: In patients in whom the terminal ileum is successfully intubated, ileoscopy is superior to barium examination in the evaluation of Crohn's disease of the terminal ileum. Results of the barium study were strongly influenced by the quality of the examination.

Forceps biopsy and brush cytology during endoscopic retrograde cholangiopancreatography for the diagnosis of biliary stenoses.

BACKGROUND: For evaluating pancreaticobiliary stenoses during endoscopic retrograde cholangiopancreatography (ERCP) tissue sampling techniques may be important. Brush cytology and forceps biopsy during ERCP are two potential, but so far only incompletely evaluated, tools for the diagnosis of malignant biliary or pancreatic stenoses. METHODS: Between 1992 and 1995 we acquired 133 cytologic and/or histologic samples from 119 patients who underwent ERCP because of biliary duct stenoses. Sixteen patients had to be excluded from the study due to insufficient follow-up information. After papillotomy, brush cytology was performed in 65 cases (63 patients), and forceps biopsy in 119 cases (106 patients under fluoroscopic guidance. Both methods were applied in combination 51 times (48 patients). The nature of the stenoses was confirmed by surgery, autopsy, or by the subsequent clinical course. RESULTS: The sensitivity was 46.7% for brush cytology and 64.9% for forceps biopsy. The combined application of both methods resulted in superior sensitivity (70.4%). Specificity was 100% for all methods. CONCLUSIONS: These numbers lead us to recommend a combined and more frequent application of brush cytology and forceps biopsy of bile duct stenoses to enhance the diagnostic yield whenever substantial influence on therapy can be expected.

Whipple's disease: comparison of histology with diagnosis based on polymerase chain reaction in four consecutive cases.

BACKGROUND: Polymerase chain reaction (PCR) based detection of species specific sequences of the 16S rRNA gene of Tropheryma whippelii is a recently described method for diagnosis of Whipple's disease. AIMS: Comparison of histology with PCR in mucosal samples of patients with Whipple's disease before, during, and after treatment. Detection of T whippelii in peripheral blood mononuclear cells as a non-invasive test for infection. METHODS: Four consecutive patients with histologically proven Whipple's disease were studied prospectively. RESULTS: In untreated patients biopsy specimens taken from regions with PAS positive macrophages gave a positive result with PCR for T whippelii; however, a PCR signal was also found in tissue biopsy specimens from mucosal regions with negative histology. In two of the patients the PCR performed with nucleic acids extracted from peripheral blood mononuclear cells was positive. After treatment with sulfamethoxazole/trimethoprim the PCR became negative after one month in two patients and after two months in the third patient treated, whereas PAS positive macrophages were found throughout the treatment period in two patients and disappeared in only one of them thereafter. CONCLUSIONS: Detection of T whippelii specific sequences based on the PCR is useful to confirm the diagnosis, is able to detect a positive signal in samples taken from histologically negative mucosal areas, and can be used to monitor treatment. The PCR can sometimes be positive in peripheral blood mononuclear cells, but this cellular compartment cannot be taken as a substitute for duodenal biopsy specimens in the diagnosis of Whipple's disease.

Severe pulmonary hypertension reversed by antibiotics in a patient with Whipple's disease.

The case is described of a 58 year old man with systemic Whipple's disease with pericardial and pleural effusions and severe pulmonary hypertension. After three months of antibiotic treatment there was a complete resolution, not only of the symptoms known to be associated with Whipple's disease (diarrhoea, arthralgia, pericardial and pleural effusions), but also of pulmonary hypertension.

Prognostic role of inducible ventricular tachycardia in patients with dilated cardiomyopathy and asymptomatic nonsustained ventricular tachycardia.

We studied the prognostic relevance of inducible ventricular tachycardia in 32 patients with dilated cardiomyopathy and spontaneous nonsustained asymptomatic ventricular tachycardia. Programmed ventricular stimulation included basic drive cycle lengths of 600, 500, 430, 370, 330 and 300 msec at single, double, and triple extrastimuli. Ventricular tachycardia (greater than or equal to 6 beats) was initiated in 7 patients (22%), with sustained monomorphic ventricular tachycardia being seen in 4 of them. During median follow-up of 21 months (13-44), 14 patients died. Sudden cardiac death occurred in two of the seven patients with inducible tachycardia and in only one of the 25 patients in whom it was not possible to induce tachycardia. Although patients with inducible tachycardia did not differ clinically from those in whom tachycardia could not be induced, the projected mean survival time was significantly shorter in those with inducible tachycardia (10 months vs. 32 months, P = 0.04). For late sudden cardiac death, the positive predictive value of inducible tachycardia was 28%. The negative predictive value was 96%. We conclude that induction of ventricular tachycardia by programmed stimulation might indicate poorer prognosis in patients with dilated cardiomyopathy.

Azidothymidine (AZT) in the treatment of symptomatic HIV-1-infected hemophiliacs.

Twenty-one immunodeficiency virus 1 (HIV 1)-positive hemophilic patients were treated with Azidothymidine (AZT) for symptomatic HIV infection. The median observation period was 20.5 months. At 25 months the probability of survival was 82%, the probability of progression of disease from CDC III or IV C2 to IV C1 (AIDS) was 20% in patients on continuous AZT treatment and 50% in patients with interruption of treatment. Three patients developed severe leukopenia and 3 patients severe anemia during AZT treatment. In 1 patient a dose-dependent striking increase of transaminases during AZT treatment was observed. In 7 patients treatment was interrupted, in 1 patient because of anemia, in 1 because of pruritus and in 5 patients because of non-compliance. No significant changes in the consumption of clotting factor concentrates and number of bleeding episodes before and during AZT treatment were noted. We conclude, that both hematological and non-hematological side effects of AZT in HIV 1-infected hemophilic patients are comparable to those seen in other risk groups. AZT does not increase the bleeding tendency in this patient group.

Gamma-interferon in myelodysplastic syndromes: a pilot study.

Eight patients with myelodysplastic syndrome (MDS; RA = 1, RAEB = 2, RAEB-t = 4, CMML = 1) received three cycles of recombinant gamma-IFN administered in 2-week intervals, each consisting of a 14-day period of subcutaneous injections at a daily dose of 0.1 mg/m2. Neither a complete nor a partial remission could be obtained. There was only one definite improvement consisting in a rise of hemoglobin level from 7 to more than 12 g/dl. Two minor improvements were due to a slight rise of platelet counts. Three patients developed acute leukemia under treatment with gamma-IFN. Our data suggest that gamma-IFN administered according to the treatment schedule as used in our trial has only a minimal beneficial effect in patients with MDS.

High risk of acquired immune deficiency syndrome (AIDS) and of AIDS related complex (ARC) in hemophiliacs seropositive for more than 5 years.

A group of 90 hemophiliacs who had been regularly treated with non virus-inactivated factor VIII or IX concentrates were studied in 1983. At that time 50 patients were HIV-1-antibody positive, 6 additional seroconversions occurred until 1985. 26 of the 50 patients seropositive in 1983 are currently asymptomatic. 4 patients have developed the lymphadenopathy syndrome, 9 patients AIDS and 11 patients ARC (CDC IV C 2). 6/9 cases of AIDS and 10/11 cases of ARC have occurred only after 1985. Patients, who subsequently became symptomatic, had significantly higher IgG levels in 1983, otherwise no predictive laboratory tests were identified. Patients with T4 counts above 500/microliters became symptomatic later, but after 5 years the incidence of AIDS was comparable in patients with original T4 counts of more than or below 500/microliters.

Anticardiolipin antibodies are elevated in HIV-1 infected haemophiliacs but do not predict for disease progression.

Levels of anticardiolipin antibodies (ACA) were measured in 55 patients with haemophilia A in serum samples obtained in 1983 and in 1987. Twenty-one patients were negative for anti HIV-1 antibodies in 1983 and remained negative in 1987; 34 patients had anti HIV-1 antibodies in 1983; 17 of these latter patients remained asymptomatic, whereas 17 patients developed ARC or AIDS during the 4 years follow-up. Thirteen anti HIV-1 negative patients had elevated ACA levels in 1983; subsequently, a significant decrease was observed in all these subjects (p less than 0.001). All anti HIV-1 positive patients had elevated ACA levels in 1983; normal values were found in 9 patients in 1987. Yet, these changes were not significant (p greater than 0.05). ACA levels were significantly higher in HIV-1 infected patients than in those without anti HIV-1 antibodies (p less than 0.05). There was no difference of ACA levels between the two anti HIV-1 positive patient groups, be it in 1983 or be it in 1987 (p greater than 0.05). There was no correlation of ACA levels with serum IgG concentrations, CD4+ lymphocytes, or the consumption of factor VIII concentrates.

Effects of 3-azidothymidine on platelet counts, indium-111-labelled platelet kinetics, and antiplatelet antibodies.

Treatment of the acquired immunodeficiency syndrome with 3-azidothymidine (zidovudine; AZT) can induce severe neutropenia and anemia, while platelet counts increase. In order to understand the mechanism by which this favorable effect on platelets is induced, we prospectively studied platelet kinetics and platelet serology in 8 hemophiliacs receiving the drug. All patients underwent a second investigation after 3 months of treatment. Four patients were thrombocytopenic before treatment. Platelet counts increased significantly already after 1 week of treatment (p = 0.03), when only 3 patients remained thrombocytopenic. In these latter patients a further increase of platelet counts was noticed during the following 3 months. Platelet life-span was shortened in all patients at the initial investigation and a significant prolongation was measurable at the second evaluation (p = 0.015). Platelet-associated immunoglobulin G was increased in 3 patients at the first investigation and in 4 patients at the follow-up. Platelet-associated complement (PAC3d) was elevated in all subjects at the first determination. It decreased in 6, but increased in 2 patients thereafter; thus these changes did not become significant (p = 0.078). Immunofluorescence studies revealed antiplatelet antibodies in 7 patients' sera before treatment, and in 5 sera during drug therapy. At both investigations, the antibodies bound to the platelet glycoprotein IIIa as was demonstrated by immunoprecipitation of radiolabeled platelet proteins. We conclude, that AZT treatment improves platelet counts in HIV-infected hemophiliacs primarily by a prolongation of platelet survival without having a significant influence on antiplatelet antibody binding.

Human blood basophils display a unique phenotype including activation linked membrane structures.

To evaluate the membrane marker profile of human basophils a panel of well-established monoclonal antibodies (MoAbs, n = 60) was used for a combined toluidine/immunofluorescence staining procedure. Myeloid-associated MoAbs (particularly MoAbs against the LFA-1 family (CD11, CDw18), MoAbs directed against lactosylceramide (CDw17), anti-glycoprotein (gp) 150 MoAbs MCS 2 and MY 7 (CDw13), anti-gp 67 MoAb MY 9, anti Fc gamma-receptor (mol wt 40 kd) MoAb CIKM5, anti-CR 1 MoAb E 11, and the antiglycolipid MoAb VIM-2) were reactive with basophils, indicating a close relationship to other mature myeloid cells. Under normal conditions, basophils surprisingly express at least three activation-linked structures not detectable on mature neutrophils, ie, the p45 structure defined by MoAbs OKT-10 and VIP-2b, the p24 structure identified by the CD9 MoAb BA-2, and the receptor for interleukin 2 (IL 2) recognized by three different MoAbs (anti-TAC, IL2RI, anti-IL 2). Moreover, under short-term culture conditions basophils both in mononuclear cell (MNC) suspension and as purified fractions display the HLA-DR and T4 antigens. The neutrophilic/eosinophilic structure 3-fucosyl-N-acetyllactosamine is expressed on basophils only after neuraminidase treatment. Basophils were not stained at all by CD 16 MoAbs directed against the Fc gamma-receptor (mol wt 50 to 70 kd) of neutrophils, by the MoAb 63D3 (CDw12) recognizing the monocyte/granulocyte-associated p 200 antigen, and by the CDw 14 antibodies (VIM-13, Mo 2) defining the monocyte-specific structure p 55. Enriched basophils freshly obtained from chronic granulocytic leukemia (CGL) patients yielded identical results in FACS analyses. In summary, these data indicate that basophils generate a unique combination of surface determinants and possibly represent an activated cell population.

T lymphocytes lack rearrangement of the bcr gene in Philadelphia chromosome-positive chronic myelocytic leukemia.

To study the possible involvement of T lymphocytes in Philadelphia chromosome (Ph)-positive chronic myelocytic leukemia (CML) we analyzed the arrangement of the bcr gene in T cell and non-T cell samples of 12 CML patients. Although all the patients showed bcr rearrangements in non-T cell fractions, T cell populations lacked respective gene recombinations. Moreover, by Southern blot analyses using T cell receptor beta chain sequences our data indicate polyclonality of T cell samples from 11 of 12 cases; in one patient a clonal T cell population could be identified. These results suggest that T lineages of most Ph-positive CML patients are not derived from pluripotent stem cells involved in leukemogenesis and thus confirm previous investigations based on cytogenetic or glucose-6-phosphate dehydrogenase analyses. The demonstration of polyclonal T cell populations may reflect persistence of stem cells committed to differentiate only into T cells.