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Biomedical subjects

J Rapp

Publications and source records attributed to J Rapp.

At least 19 recordsLinked to original sources
PubMed2003

Biochemical characterization of atherosclerotic plaque constituents using FTIR spectroscopy and histology.

The behavior of vulnerable atherosclerotic plaques is believed to be closely related to plaque composition. There is a need for an effective in vivo technique for examining plaque constituent properties. In this study, Fourier transform infrared spectroscopy using attenuated total reflectance (FTIR-ATR) was used to assess and analyze the biochemical properties of human atherosclerotic plaques. FTIR spectra clearly revealed prominent spectral features corresponding to plaque constituents of interest: the 2930 cm(-1) and 2850 cm(-1) peaks (indicating the presence of lipids), the 1730 cm(-1) peak (lipid esters), the 1550 cm(-1) and 1650 cm(-1) peaks (fibrous tissues), and the 1100-1000 cm(-1) broad phosphate peak (calcification). Spectral data examined on a qualitative basis correlated well with both gross tissue anatomy and histologic features. Gross spatial mappings of tissue sections of both lipidic and calcified plaques were performed. Spectra from various regions of the plaques demonstrated the evolution of lipid peaks, fibrous tissue peaks, and the phosphate calcification band within the plaques. Histologic analysis corroborated the spectral findings in this study.

Arteriosclerosis↗
PubMed2002

Control of neoclassical tearing modes by sawtooth control.

The onset of a neoclassical tearing mode (NTM) depends on the existence of a large enough seed island. It is shown in the Joint European Torus that NTMs can be readily destabilized by long-period sawteeth, such as obtained by sawtooth stabilization from ion-cyclotron heating or current drive. This has important implications for burning plasma scenarios, as alpha particles strongly stabilize the sawteeth. It is also shown that, by adding heating and current drive just outside the inversion radius, sawteeth are destabilized, resulting in shorter sawtooth periods and larger beta values being obtained without NTMs.

Journal Article↗
PubMed2001

Endoleak after endovascular repair of abdominal aortic aneurysm.

PURPOSE: We sought to assess the role of endovascular techniques in the management of perigraft flow (endoleak) after endovascular repair of an abdominal aortic aneurysm. METHOD: We performed endovascular repair of abdominal aortic aneurysm in 114 patients, using a variety of Gianturco Z-stent-based prostheses. Results were evaluated with contrast-enhanced computed tomography (CT) at 3 days, 3 months, 6 months, 12 months, and every year after the operation. An endoleak that occurred 3 days after operation led to repeat CT scanning at 2 weeks, followed by angiography and attempted endovascular treatment. RESULTS: Endoleak was seen on the first postoperative CT scan in 21 (18%) patients and was still present at 2 weeks in 14 (12%). On the basis of angiographic localization of the inflow, the endoleak was pure type I in 3 cases, pure type II in 9, and mixed-pattern in 2. Of the 5 type I endoleaks, 3 were proximal and 2 were distal. All five resolved after endovascular implantation of additional stent-grafts, stents, and embolization coils. Although inferior mesenteric artery embolization was successful in 6 of 7 cases and lumbar embolization was successful in 4 of 7, only 1 of 11 primary type II endoleaks was shown to be resolved on CT scanning. There were no type III or type IV endoleaks (through the stent-graft). Endoleak was associated with aneurysm dilation two cases. In both cases, the aneurysm diameter stabilized after coil embolization of the inferior mesenteric artery. There were two secondary (delayed) endoleaks; one type I and one type II. The secondary type I endoleak and the associated aneurysm rupture were treated by use of an additional stent-graft. The secondary type II endoleak was not treated. CONCLUSIONS: Type I endoleaks represent a persistent risk of aneurysm rupture and should be treated promptly by endovascular means. Type II leaks are less dangerous and more difficult to treat, but coil embolization of feeding arteries may be warranted when leakage is associated with aneurysm enlargement.

Aortic Aneurysm, Abdominal↗
PubMed2001

Protein and lipid deposition onto hydrophilic contact lenses in vivo.

PURPOSE: To investigate the mechanism of protein and lipid adherence to hydrophilic contact lenses in vivo. METHODS: Two types of new, never-worn hydrophilic contact lenses (tefilcon and vifilcon) were simultaneously worn by eight experienced, asymptomatic contact lens wearers on 12 separate occasions. Deposited lipids were removed with a methanol based extraction procedure, separated using high performance thin layer chromatography, and quantitatively analyzed densitometrically. Deposited proteins were extracted with 4M urea, separated using gel electrophoresis and quantitatively analyzed densitometrically. RESULTS: Four lipids and one protein were deposited in quantifiable amounts onto each worn lens. Lysozyme demonstrated material-dependent deposition whereas total lipid did not. Subject-dependent differences in the deposition of both lysozyme and total lipid were observed primarily on group IV lenses. The deposition of triolein, the largest lipid extracted, was found to be material- but not subject-dependent. The deposition of smaller lipids was found to be subject-but not material-dependent. CONCLUSIONS: Significant amounts of both protein and lipid were extracted from both types of lenses after 1 day of wear. Lysozyme deposition was material-dependent because of its affinity for negative charges on group IV lenses. The abundance of binding sites on a group IV lens allows protein and lipid deposition to be subject-dependent after short periods of wear. Lipid deposition appears to be influenced by size. Collectively, the results suggest that subject-dependent variations in deposition are modulated by both material and contaminant characteristics.

Chromatography, Thin Layer↗
PubMed2000

Quasistationary high confinement discharges with trans-greenwald density on TEXTOR-94

Confinement quality as good as ELM-free H-mode at densities substantially above the Greenwald density limit ( &nmacr;(e,0)/n(GW) = 1.4) has been obtained in discharges with a radiative boundary under quasistationary conditions for 20 times the energy confinement time. This is achieved by optimizing the gas-fueling rate of RI-mode discharges which tailors their favorable energy confinement and leads to discharges with beta values just below the operational limit beta(n) = 2 of TEXTOR-94, thereby effectively avoiding confinement back transitions or disruptions. In addition, this high-density regime is favorable for helium removal and results in figures of merit tau(*)(p,He)/tau(E) approximately 10-15, relevant for a future fusion power reactor.

Journal Article↗
PubMed2000

[Levels of interleukin-4, interleukin-5, tryptase and eosinophil cationic protein of nasal lavage fluid in pollen allergic rhinitis].

IL-4, IL-5, tryptase and eosinophil cationic protein levels were measured in nasal lavage fluid from 15 pollen allergic rhinitis beyond pollen season. Allergy was proved by prick test. There were 15 non allergic children in the control group. Specific nasal allergen provocation was performed on the rhinitic group. Nasal lavage were done before, 1 and 12 hours after the provocation. Before the nasal provocation the ECP and IL-4 levels were significantly higher in the allergic group compared to the non allergic group. The levels of tryptase, ECP and IL-4 rose significantly after the provocation. The results reflect to the possibility of an activated immune status in allergic rhinitis even without the presence of the triggering pollens. After the specific provocation elevated tryptase levels were measured, referring to the activity of the early phase of the I. type hypersensitivity reaction, while the ECP and IL-5 elevation to its late phase. According to our examinations it can be said, that tryptase, ECP and IL-5 might be used to detect the activation of the early and late phases of the IgE mediated hypersensitive reaction.

Adolescent↗
PubMed2000

Endovascular aneurysm repair in high-risk patients.

PURPOSE: The purpose of this study was to evaluate the role of endovascular aneurysm repair in high-risk patients. METHODS: The elective endovascular repair of infrarenal aortic aneurysm was performed in 116 high-risk patients with either custom-made or commercial stent grafts. The routine follow-up examination included contrast-enhanced computed tomography (CT) before discharge, at 3, 6, and 12 months, and annually thereafter. Patients with endoleak on the initial CT underwent re-evaluation at 2 weeks. Those patients with positive CT results at 2 weeks underwent endovascular treatment. RESULTS: Endovascular repair was considered feasible in 67% of the patients. The mean age was 75 years, and the mean aneurysm diameter was 6.3 cm. The American Society of Anesthesiologists grade was II in 3.4%, III in 65.5%, IV in 30.1%, and V in 0.9%. There were no conversions to open repair. Custom-made aortomonoiliac stent grafts were implanted in 77.6% of the cases, custom-made aortoaotic stent grafts in 11.2%, and commercial bifurcated stent grafts in 11.2%. The 30-day rates of mortality, major morbidity, and minor morbidity were 3.4%, 20.7%, and 12%, respectively, in the first 58 patients and 0%, 3.4%, and 3.4%, respectively, in the last 58. The late complications included five cases of stent graft kinking, two cases of femorofemoral graft occlusion, and three cases of proximal stent migration, one of which led to aneurysm rupture. At 2 weeks after repair, endoleak was present in 10.3% of the cases. All the type I (direct perigraft) endoleaks underwent successful endovascular treatment, whereas only one type II (collateral) endoleak responded to treatment. The technical success rate at 2 weeks was 86.2%, and the clinical success rate was 96.6%. The continuing success rate was 87.9%. Seventeen patients died late, unrelated deaths. CONCLUSION: Endovascular aneurysm repair is safe and effective in patients at high risk, for whom it may be the preferred method of treatment.

Aged↗
PubMed1999

Immunological grouping of 53 antibodies against prostate-specific antigen.

Microtiter immunoassays were used to determine whether a panel of 53 monoclonal antibodies submitted to the ISOBM TD-3 PSA Workshop could form assay combinations with free prostate-specific antigen (PSA) and the PSA complex with alpha1-antichymotrypsin. A panel of 6 known anti-PSA antibodies (H117, H50, H179, H164, 2E9 and 5A10) was used as labelled tracers. Epitope groups were proposed based on the ability of the Workshop antibodies to form good assay combinations with these 6 known anti-PSA antibodies. Nine of the TD-3 Workshop antibodies were found to react only with free PSA. Two additional epitope clusters were identified with 8 antibodies showing similar reactivity to antibody H117, while 11 antibodies formed a different cluster showing similar reactivity to antibody H50. Defining the nature of these immunodominant regions will be valuable in the development of more appropriate immunoassays for PSA.

Antibodies, Monoclonal↗
PubMed1998

Rapid and sensitive reverse transcriptase-polymerase chain reaction based detection and differential diagnosis of fish pathogenic rhabdoviruses in organ samples and cultured cells.

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay was developed and applied to the detection and differentiation of viral haemorrhagic septicaemia virus (VHSV) and infectious hematopoietic necrosis virus (IHNV) in organ samples and cultured cells, regardless of the serotype. This method was developed by selecting primer sets corresponding to highly conserved regions of the glycoprotein G-gene sequences of the 2 viruses. The very fast RNA extraction, reverse transcription and PCR permitted us to read the agarose gels within 7 to 9 h after samples, cultured cells and whole fish arrived, which is of great importance when there is reason to believe that VHSV or IHNV may be present. This is also the first report of a large-scale field trial comparing the RT-PCR assay in trout from 30 German fish farms (a total of 330 rainbow trout) with the usual virus isolation and identification method in order to evaluate the efficiency of the RT-PCR assay for general use in fish health management programs. RT-PCR followed by semi-nested PCR using RNA directly extracted from fish tissue turned out to be the most sensitive method. It recognized 9 fish farms as VHS-positive and 7 as IHN-positive. This is 3 VHS- and 4 IHN-farms more than detected by the traditional virus isolation method. By directly examining the tissue by means of a PCR test it was possible to detect viral RNA in acutely and subacutely to chronically diseased fish as well as in asymptomatic VHS/IHN-carrier fish. Therefore, this effective and powerful assay for detecting VHSV and IHNV by means of PCR has great advantages compared with the presently used procedures.

Animals↗
PubMed1998

Determination and analysis of antigenic epitopes of prostate specific antigen (PSA) and human glandular kallikrein 2 (hK2) using synthetic peptides and computer modeling.

Prostate specific antigen (PSA) and human glandular kallikrein 2 (hK2), produced essentially by the prostate gland, are 237-amino acid monomeric proteins, with 79% identity in primary structure. Twenty-five anti-PSA monoclonal antibodies (Mabs) were studied for binding to a large array of synthetic linear peptides selected from computer models of PSA and hK2, as well as to biotinylated peptides covering the entire PSA sequence. Sixteen of the Mabs were bound to linear peptides forming four independent binding regions (I-IV). Binding region I was localized to amino acid residues 1-13 (identical sequence for PSA and hK2), II (a and b) was localized to residues 53-64, III (a and b) was localized to residues 80-91 (= kallikrein loop), and IV was localized to residues 151-164. Mabs binding to regions I and IIa were reactive with free PSA, PSA-ACT complex, and with hK2; Mabs binding to regions IIb, IIIa, and IV were reactive with free PSA and PSA-ACT complex, but unreactive with hK2; Mabs binding to region IIIb detected free PSA only. All Mabs tested (n = 7) specific for free PSA reacted with kallikrein loop (binding region IIIb). The presence of Mabs interacting with binding region I did not inhibit the catalytic activity of PSA, whereas Mabs interacting with other binding regions inhibited the catalysis. Theoretical model structures of PSA, hK2, and the PSA-ACT complex were combined with the presented data to suggest an overall orientation of PSA with regard to ACT.

Amino Acid Sequence↗
PubMed1998

Brief application of simplified habit reversal to treat stuttering in children.

We evaluated a brief therapy protocol involving the simplified regulated breathing method as a treatment for stuttering in children. The simplified treatment included awareness training, competing response training, and social support. Treatment was implemented in a multiple baseline across subjects design for 5 boys between the ages of 5 and 11. Each child received a 1 h treatment session, and 1/2 h booster sessions as needed. Four of the 5 children reduced their stuttering to less than 3% stuttered words (the criterion for successful treatment) after one 1 h treatment session. These results were maintained for 3 of the subjects from 6 to 9 months posttreatment. Social validity measures revealed significant differences between ratings on baseline and posttreatment speech samples. Treatment acceptability and credibility measures indicated that the subjects' guardians found the simplified regulated breathing method a reasonable treatment for stuttering in children.

Behavior Therapy↗
PubMed1998

Staying power.

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Aged↗
PubMed1997

Pathological and epidemiological aspects of skin lesions in histoplasmosis. Observations in an AIDS patient and badgers outside endemic areas of histoplasmosis.

As a consequence of HIV infection, histoplasmosis is increasingly occurring as an opportunistic infection with a systemic course outside histoplasmosis-endemic areas, e.g. in Europe. Accordingly, questions concerning the epidemiology of this mycosis arise. Two incidents involving histoplasmosis in man and badgers with prevailing involvement of the skin encouraged us to review the pathogenesis and epidemiology of this mycosis in Germany, where so far Histoplasma capsulatum has not been endemic. With a view to prevention, attention is drawn to the avoidance of microfoci of H. capsulatum in the newly introduced concept of biowaste and its composting plants in countries with modern waste management.

AIDS-Related Opportunistic Infections↗
PubMed1997

Immune response to the filaria Litomosoides sigmodontis in susceptible and resistant mice.

Comparisons were made between the immune responses evoked during the course of chronic and patient infections of Litomosoides sigmodontis in susceptible BALB/c mice and non-patent infections in resistant B10.D2 mice. Early antigen specific responses of spleen cells were weak in both mouse strains. However, by day 58 post infection a strong Th2 response, as determined by production of IL-4, IL-5 and IL-10, was observed in BALB/c mice but not in B10.D2 mice. Antibody responses seemed to appear sooner in B10.D2 than in BALB/c mice, and these differentially recognised two antigens of 15 kD and 80 kD.

Animals↗
PubMed1997

Protein-lipid interaction on the surface of a rigid gas-permeable contact lens in vitro.

PURPOSE: To investigate the mechanism of protein-lipid interactions responsible for biofilm formation on the surface of rigid gas-permeable contact lenses in vitro. METHODS: Two types of new, never-worn rigid gas-permeable contact lenses (siloxanyl alkyl acrylate and fluorosiloxanyl alkyl acrylate) were individually incubated in a protein only, lipid only, or combination protein-lipid artificial tear solution for 24 h at 37 degrees C with constant stirring. Deposited lipids were removed with a methanol based extraction procedure, separated using high performance thin layer chromatography and quantitatively analyzed densitometrically. Deposited proteins were extracted with 4M urea, separated using gel electrophoresis and quantitatively analyzed densitometrically. RESULTS: Lipid deposition on rigid gas-permeable contact lenses is dependent on lens matrix hydrophobicity while protein deposition is minimal and not material-dependent. The presence of lipid in the artificial tear solution enhances protein deposition on both types of rigid gas-permeable materials examined. The presence of protein in the artificial tear solution decreases lipid deposition on a siloxanyl alkyl acrylate lens. CONCLUSIONS: The hydrophobic nature of rigid gas-permeable contact lenses causes them to be more prone to lipid than to protein deposition. When both types of molecule are present in an artificial tear solution, the hydrophobic sites of the lipid molecules are attracted to the lens matrix while the more hydrophilic sites are repelled by the matrix and, thereby, exposed to the aqueous surroundings. Thus, lipid binding to rigid gas-permeable contact lenses reduces the hydrophobicity of the lens surface allowing protein to bind. The bound deposited hydrophilic protein then alters subsequent binding of both protein and lipid.

Contact Lenses↗
PubMed1997

Protein-lipid interaction on the surface of a hydrophilic contact lens in vitro.

PURPOSE: To investigate the mechanism of protein-lipid interactions responsible for biofilm formation on the surface of hydrophilic contact lenses in vitro. METHODS: New, never-worn hydrophilic contact lenses were individually incubated in a protein-only, lipid-only, or combination protein-lipid artificial tear solution for 24 hours at 37 degrees C with constant stirring. Deposited lipids were removed with a methanol based extraction procedure, separated using high-performance, thin layer chromatography and quantitatively analyzed densitometrically. Deposited proteins were extracted with 4M urea, separated using gel electrophoresis and quantitatively analyzed densitometrically. RESULTS: The presence of protein in the artificial tear solution has a profound effect on the nature of lipid deposition for each group of hydrophilic lens, whereas the presence of lipid has a significant effect on the nature of protein deposition for only a group IV lens. In addition, the presence of lipid deposits on a group IV lens decreases the adsorption of lysozyme, while the presence of protein deposits reduces the amount of total lipid adhering to a group II lens. CONCLUSIONS: Protein adsorption on a group IV lens renders the lens surface less hydrophilic and, thereby, more susceptible to lipid deposition, which in turn increases surface hydrophobicity and inhibits additional protein deposition. For a group II lens, positively charged protein competes with and replaces some of the polar lipids attached to the lens. Thus, the interaction of protein and lipid on a lens surface most prone to a particular contaminant apparently makes it less likely for that contaminant to bind.

Adsorption↗