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Biomedical subjects

T Hoffmann

Publications and source records attributed to T Hoffmann.

At least 109 records · Page 6Linked to original sources
PubMed1992

[A clinico-histological study for the diagnosis and classification of spontaneous periodontal diseases in the dog].

Using standardized investigation methods periodontal parameters were proved for diagnostic application of spontaneous periodontal diseases in dogs. The diseases are classified in gingivitis simplex, g. granulomatosa, g. ulcerosa, g. hyperplastica, g. desquamativa, juvenile periodontitis, rapidly progressive p. and chronic p. This proposal can be used for further investigations in experimental dentistry and for therapeutic purposes in veterinary dentistry.

Animals↗
PubMed1991

[Health status and late complications following allogeneic bone marrow transplantation. A review].

Better results following bone marrow transplantation (BMT) have increased the number of patients in longterm follow-up. Health status and late effects are therefore of increasing interest. We discuss here the incidence and follow-up of late complications after allogenic BMT. Any conditioning regimen including TBI in postpubertal women introduces a postmenopausal status. In contrast, normal function is found after BMT without irradiation. In men, there is usually permanent azoospermia after TBI but not following chemotherapy alone. Thyroid dysfunction after BMT with TBI has been reported in about 40% of patients. In most of them compensated hypothyroidism with elevated TSH is found. BMT with TBI induces growth retardation in children. Decreased growth hormone levels are observed and substitution can induce normal height development. Interstitial pneumonitis (IP) is a major cause of death. It occurs on average three months after BMT but late onset IP's are increasingly reported. Cataracts are common after BMT. The risk of cataracts in patients given single dose TBI attains 80-100% after four years. Under treatment with cyclophosphamide alone, the risk of lens opacification is less than 20%. So far, patients treated with fractionated TBI have not developed more cataracts than those treated with chemotherapy alone. Impaired renal function is common early post-transplant. Risk factors include cyclosporine (CSA) nephrotoxic antibiotics and antifungal drugs. So far, few secondary malignancies have been reported in humans after BMT. However, actual observation time is still too short for final evaluation. Prevention or treatment is instituted for common complications. It is expected that other types of tissue damage will be recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Inhibiting effect of a pyrophosphate-dentifrice on calculus formation].

Anticalculus dentifrices containing pyrophosphate salts have been shown to reduce calculus formation. The purpose of this double-blind, cross-over study was to compare the effects of a pyrophosphate dentifrice with a placebo on supragingival calculus formation in highly calculus-prone subjects. 60 volunteers completed a compliance period during which meticulous full-mouth scaling was performed. Subjects were randomly assigned either to placebo (F-Antibelag Gel) or to the test group (F-Antibelag Gel + K4P2O7/Na4P2O7). Participants were told to brush twice daily with their assigned dentifrice, use only the brushes provided and to abstain from any other oral hygiene procedures. After a three month period a second full-mouth scaling was performed, and according to the cross-over design of this study the participants used the alternative placebo or, respectively, dentifrice for another three months. Baseline scores and control scores after 1, 2 and 3 months were obtained using the Volpe-Manhold-Index and the Marginal-Line-Calculus-Index. A micromorphological SEM Calculus Index was introduced using replicas from interdental areas of mandibular incisors (score 0-3). Both test groups showed significantly less accumulation of supragingival calculus of 25.5% (VMI) and 19.5% (MLCI) and significantly less SEM detectable calculus (24%) with the pyrophosphate dentifrice than with the placebo. It is concluded that the test dentifrice inhibits the formation of calculus.

Adult↗
PubMed1991

[Clinical-controlled valuation of the conservative and surgical therapy by periodontitis marginalis].

The present investigation describes in a two years study the effect of conservative local therapy with and without surgical intervention and the reliability of the parameters (SLI, GI, SBI, pocket depth, attachment level and finally the microbiological examination (GRAM-technique). Reexamination was carried out in a recall system of 2, 4 and 12 weeks, also 6, 12 and 18 months after completing the determined therapy procedure. Analysis was carried out by means of the mean value, Student's t-test, correlation analysis and documenting the individual status respectively. Both treatment methods resulted in positive results. Individual variations among patients were noted. Deep pockets were initially more reduced by surgical intervention than by conservative local treatment alone. Principally, surgical intervention shows as a result more sites surfaces with progression of periodontitis than after conservative local treatment. Attachment loss is the most correct sign of periodontal progression. Decisions for surgical intervention should be based on follow-up documentation and individual patient reactions.

Adult↗
PubMed1990

Aggregation behaviour of blood granulocytes in patients with periodontal disease.

This behaviour was studied in 17 patients with severe marginal periodontitis and in 16 healthy controls. Aggregation induced by platelet-activating factor (PAF-acether), a potent mediator of inflammation, was significantly enhanced in the patients, whereas no significant difference was observed between patients and controls when aggregation was induced by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP). When the patients were subdivided into categories of progressive adult periodontitis, juvenile or post-juvenile periodontitis, aggregation induced by PAF-acether was enhanced in all three subgroups. However, FMLP-induced aggregation was slightly increased only in progressive adult and post-juvenile periodontitis, but decreased in juvenile periodontitis.

Adolescent↗
PubMed1990

Comparative analysis of in vivo T cell depletion with radiotherapy, combination chemotherapy, and the monoclonal antibody Campath-1G, using limiting dilution methodology.

We have investigated the efficacy of standard conditioning regimens for bone marrow transplantation in depleting functional T lymphocytes in vivo and have compared it with the efficacy of the monoclonal antibody Campath-1G. Using limiting dilution techniques the frequencies of proliferating T cell precursors (PTL), cytotoxic T cell precursors (CTL-p), helper T cell precursors (HTL-p), and mature helper T cells (HTL) were determined before and after treatment. Both total body irradiation and combination chemotherapy with busulfan/cyclophosphamide were highly efficient at depleting PTL, CTL-p, and HTL-p (0-4 days) but spared HTL to a variable extent (0-99.5%). In the majority of patients treated with Campath-1G a similar degree of PTL, CTL-p, and HTL-p depletion was achieved, and, in addition, HTL were effectively removed (greater than 95.5%). These results suggest that Campath-1G could be successfully employed in depleting radio- and chemotherapy-resistant host T lymphocytes prior to T-depleted bone marrow transplantation.

Antibodies, Monoclonal↗
PubMed1990

Frequency, specificity, and phenotype of clonally growing human alloreactive interleukin-2-secreting helper T lymphocyte precursors.

Limiting dilution cultures were performed to detect allospecific IL-2-secreting helper T lymphocyte precursors (HTL-p) among human peripheral blood mononuclear cells, E-rosette-purified (E+) and cell-sorter-separated CD4+/8- as well as CD4-/8+ T cell subsets. Split-well cultures were set up prior to restimulation to assess the antigen specificity of the response. Frequencies of alloreactive IL-2-secreting HTL-p in fully HLA-mismatched responder/stimulator cell combinations ranged from 1/200 to 1/900 (among PBMNC), from 1/50 to 1/301 (among E+ T cells), from 1/36 to 1/220 (among CD4+ T cells), and from 1/38 to 1/450 (among CD8+ T cells). Allospecificity of effector T cells was demonstrated by a strong decline of frequencies obtained after restimulation against unrelated third-party antigens. In clonal segregation analysis, the vast majority of IL-2-secreting progeny (80-90%) were exclusively specific for the original stimulating alloantigen. Finally, the allele specificity of human alloreactive HTL-p was revealed by comparing frequency estimates obtained after restimulation with partially identical stimulator/third-party antigen combinations.

Alleles↗
PubMed1990

[Reattachment or new attachment in apical-marginal periodontal bone loss. A clinical-histological discussion].

Loss of marginal alveolar bone of the tooth can be caused by periodontal, pulpal-periapical, or a combined pulpal and periodontal disease. The regeneration is supported by the formation of reattachment or new attachment. Reattachment is probably the usual healing process in periapical surgery of the tooth with apicomarginal bone loss caused by pulpal-periapical disease. In animal experiments (rats, dogs) ist was well documented, that the cells which repopulate the periodontal wound adjacent to the root surface determine the nature of the attachment formed.

Animals↗
PubMed1990

[The phagocytic activity of the blood neutrophilic granulocytes in patients with marginal periodontitis].

The ingestion of opsonized zymosan particles by neutrophil blood granulocytes and the chemiluminescence in samples of whole blood, induced by zymosan, Streptococcus mutans as well as phorbol myristate acetate, as a measure of the generation of reactive oxygene species were studied in patients with various forms of marginal periodontitis. Compared to a control group the phagocytic activity was found to be enhanced in progressive adult periodontitis and diminished in juvenile periodontitis whereas no differences to controls were found in chronic nonprogressive or postjuvenile periodontitis. With respect to the height of the chemiluminescence signals increased values were only measured in chronic nonprogressive periodontitis after stimulation by phorbol myristate acetate. The results indicate that impairment of blood granulocyte functions may be a pathogenetic factor for the development and the progression of marginal periodontitis.

Adolescent↗
PubMed1990

[Ear cartilage as tarsus replacement (with long-term results)].

The authors report on 52 lid operations in combination with the transplantation of ear cartilage to serve as tarsus. The preoperative diagnoses were: ectropion (22); entropion (5); tumors (18); lid reconstruction following trauma (7). The long-term results were determined in 24 patients with 29 lids, with an average follow-up time of 26 months. The lid margin fit and the cartilage was palpable in nearly 90% of the long-term results; 83% of the patients were content with the cosmetic outcome.

Cartilage↗
PubMed1990

[Combined valuation of the success of therapy of orthodontic anomalies, periodontal diseases and dental caries].

Using the DMF/T, GPM/T and CPITN-index systems, the numerical evaluation method according to Eismann and measuring the occlusal contact areas in static occlusion in 101 orthodontically treated adolescents and young adults the effect of complex preventive and therapeutic programs was studied. The used parameters allow to characterize oral health status. After completing the orthodontical treatment there is a need to continue preventive programmes and therapeutic interventions in adults to reach stable oral health conditions.

Adolescent↗
PubMed1990

[Relation between functional-immunological and clinical parameters in juvenile periodontal diseases].

In 57 Moscow adolescents aged 15 to 19 years gingival bleeding and periodontal pocketing was recorded. In addition to this functional parameters of Rheoperiodontography and Polarography were documented and immunological investigations were carried out. The clinical parameters of the test group showed a higher level of periodontal diseases compared with a random selected control group. A correlation between clinical and functional parameters in early periodontal destruction was not detected. This study demonstrates the importance of prevention of periodontal diseases in adolescents.

Adolescent↗
PubMed1989

Assessment of human allospecific IL-2-secreting helper T lymphocytes in limiting dilution cultures using restimulation and split well analysis.

A limiting dilution (LD) culture was established which allows the detection of allospecific interleukin-2 (IL-2)-secreting helper T lymphocyte precursors (HTL-p) among human peripheral blood mononuclear cells (PBMNC). HTL-p stimulated with allogeneic Epstein-Barr virus-transformed B lymphoblastoid cell lines (EBV-LCL) in the presence of exogenous recombinant IL-2 (r-IL-2) clonally developed into IL-2 secreting effector cells when restimulated against the original stimulating alloantigen. Split well cultures were performed prior to restimulation to assess the antigen specificity of the response. Frequencies of alloreactive IL-2-secreting HTL-p ranged from 1/100 to 1/800. Allospecificity of effector T cells was determined by a strong decline of frequencies obtained after restimulation against third-party antigens. In (clonal) segregation analyses the vast majority of IL-2-secreting progenies (80%) were specific for the original stimulating alloantigen. Allele specificity was disclosed by using class II MHC related third-party restimulator cells. By comparison with LD short-term cultures it became evident that exogenous r-IL-2 in the initial culture period was required to reveal optimal precursor frequencies of IL-2-producing T cells. Furthermore, successful antigenic restimulation was strictly confined to these culture conditions.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Fibrinogen-independent platelet adhesion and thrombus formation on subendothelium mediated by glycoprotein IIb-IIIa complex at high shear rate.

Platelet adhesion and thrombus formation on subendothelium, studied at a shear rate of 2,600 s-1, were inhibited by two synthetic peptides known to interact with GPIIb-IIIa. One peptide (HHLGGAKQAGDV) corresponds to the carboxyl terminal segment of the fibrinogen gamma-chain (gamma 400-411) and the other (RGDS) contains the amino acid sequence Arg-Gly-Asp (RGD) common to fibronectin, von Willebrand factor, vitronectin and the alpha-chain of fibrinogen. Neither platelet adhesion nor thrombus formation were decreased in a patient with severe congenital fibrinogen deficiency and this was equally true when his blood was further depleted of the small amounts of fibrinogen present utilizing an anti-fibrinogen antibody. In normal subjects, adhesion and thrombus formation were inhibited by the Fab' fragments of a monoclonal anti-GPIIb-IIIa antibody (LJ-CP8), which interferes with the interaction of platelets with all four adhesive proteins in both the fluid and solid phase. However, another anti-GPIIb-IIIa antibody (LJ-P5) that had minimal effects on the interaction of platelets with fibrinogen, but inhibited to varying degrees platelet interaction with other adhesive proteins, was equally effective. The findings demonstrate that, at a shear rate of 2,600 s-1, adhesive proteins other than fibrinogen are involved in GPIIb-IIIa-mediated platelet adhesion and thrombus formation on subendothelium. In addition, since LJ-P5 inhibited the binding of soluble von Willebrand factor and vitronectin, these adhesive proteins may be involved in platelet thrombus formation. In contrast to the results obtained at a shear rate of 2,600 s-1, fibrinogen could play a role in mediating platelet-platelet interactions with weak agonists or lower shear rates.

Afibrinogenemia↗
PubMed1989

Evidence for the presence of tissue factor activity on subendothelium.

By a variety of methods, tissue factor activity was demonstrated in the subendothelium of rabbit aorta and human umbilical artery. In one method, everted segments of de-endothelialized vessels were mounted in an annular perfusion chamber and the subendothelial surface was exposed to nonanticoagulated human blood under controlled flow. Procoagulant activity was assessed by measuring fibrin deposition on subendothelium and fibrinopeptide A (FPA) levels in post chamber blood. Both fibrin deposition and FPA were decreased with rabbit vessel segments exposed (at a shear rate of 650 seconds-1) to blood from patients with factor VII deficiency and with umbilical artery segments (at shear rates of 90 to 180 seconds-1) that had been pretreated with a monoclonal antibody to human tissue factor. In a second method, everted umbilical artery segments were mounted on a stir bar and the subendothelial surface was exposed, with stirring, to plasma or purified coagulation factors. The capacity of the surface to clot plasma on addition of calcium was inhibited by the antibody to tissue factor. The surface also activated purified 3H-factor X in the presence of factor VIIa, but not in its absence, and this surface property was almost entirely eliminated by pretreating the vessel segments with antitissue factor. Tissue factor activity in subendothelium could play a role in both the arrest of bleeding and in promoting the formation of thrombi at sites of vascular injury.

Animals↗