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Biomedical subjects

T Mertens

Publications and source records attributed to T Mertens.

At least 73 records · Page 4Linked to original sources
PubMed1992

[The synthesis of collagenous and noncollagenous proteins by cells from the periodontium].

Synthesis of collagenous and noncollagenous proteins by cells originating from the alveolar bone (AB-cells) and from the periodontal ligament (PDL-cells) of 8 minipigs was analyzed in primary cell cultures. Incorporation of 3H-proline into proteins recovered from cell extracts showed, that 13.7% of protein synthesized by AB-cells and 8.0% of protein synthesized by PDL-cells were collagens. In both cell lines relative amounts of collagens synthesized decreased significantly on subculturing (AB-cells: 9.3%, PDL-cells: 6.0%). Preincubation of 2nd subculture AB-cells with beta-glycerophosphate had no significant effect on collagen synthesis. Considering the fact that relative amounts of collagen recovered from cell extracts represent only 10-20% of collagen recovered from whole culture (i.e. cells and culture medium), we suggest that collagen synthesis is an important component of in vitro-protein synthesis of cells originating from the alveolar bone and the periodontal ligament.

Alveolar Process↗
PubMed1992

[Community health workers are capable of determining reliably the target population for health programs].

The target population is a key concept for the planning and evaluation of health services. However, in developing countries, health professionals in the field are often uneasy with the determination of the population denominator. In Zaire, where reliable demographic data are hardly available, we make use of two different methods aimed to the determination of the size of the target population: (1) an exhaustive population based survey performed by trained interviewers, and (2) a rapid census of the target population performed by community health workers. This paper presents both the results of a demographic survey organized in 1984, and two consecutive census performed by community health workers in 1986 an 1988, in the same area (Northern-Kivu, Zaire). Our results suggest that community health workers under close supervision are able to perform rapidly and at low cost a reliable collection of the demographic data needed for the implementation and monitoring of health programmes at the local level.

Adolescent↗
PubMed1991

[Perimyocarditis in influenza A virus infection].

A 48-year old man was admitted with suspected acute myocardial infarction because of severe precordial pain and monophasic ST-elevations in the ECG. The patient's history of an ongoing infection, the localization, extent, and course of the ECG changes as well as the development of a pericardial effusion suggested viral perimyocarditis. The diagnosis was supported by a significant rise of antibodies (seroconversion) against influenza A virus.

Adult↗
PubMed1990

The use of cultures of human osteoblastlike cells as an in vitro test system for dental materials.

An in vitro culture of human osteoblastlike cells was established in order to perform toxicity tests with materials interacting with bone in vivo. Different dental materials were tested with osteoblastlike cells and with human gingival fibroblasts. Direct and indirect tests were performed according to the different properties of the materials. It was found that the osteoblastlike cells in test cultures were affected by materials that caused no visible cell damage in the fibroblast cultures. The results indicated that human osteoblastlike cell cultures represent a highly sensitive test system for cell-specific toxicity.

Cells, Cultured↗
PubMed1990

Virological examinations of patients with AIDS-related complex/Walter-Reed 5 enrolled in a double-blind placebo-controlled study with intravenous gammaglobulin administration. Prognostic value of anti-p24 determination. The ARC-IVIG Study Group.

Thirty patients with AIDS-related complex/Walter-Reed 5 enrolled in a placebo-controlled double-blind study with high-dose intravenous gammaglobulin administration were tested by quantitating HIV Western blot and other serological tests for viral antibodies. Furthermore, conventional virus isolation attempts were performed. Absence or loss of p24 antibodies during the study period was associated with progression to AIDS (p = 0.01) and thereby was an earlier prognostic parameter of a poor prognosis than T4 cell count. Neither changes in antibody patterns against other HIV polypeptides, HIV titers in the immunofluorescence test nor demonstration of HIV antigen were significantly associated with progression to AIDS. Cytomegalovirus (CMV) could be isolated from two duodenal biopsies of a patient who developed AIDS at the same time, but a concomitant serological diagnosis of CMV infection was not successful. Though signs in the serology of human herpesviruses (herpes simplex virus, CMV, Epstein-Barr virus), possibly indicating a reactivation of latent infections, could be observed in some instances, a correlation with clinical symptoms or the clinical outcome was not feasible, perhaps also because of a poor standardization of some of the test kits used. All patients were positive for IgG antibodies against the three herpesviruses when entering the study. High prevalence of hepatitis B virus (HBV) markers was found (83% anti-HBc positive), only 1 patient being chronically infected and highly infectious, as shown by HBV-DNA hybridization. No significant difference between treatment and placebo group was observed with the parameters tested in this study.

AIDS-Related Complex↗
PubMed1990

Lymphocyte proliferation in AIDS-related complex/Walter-Reed 5 patients: response to herpes simplex virus and tuberculin antigen and mitogen during intravenous immunoglobulin treatment. The ARC-IVIG Study Group.

In a randomized, controlled double-blind study, 15 patients with AIDS-related complex/Walter-Reed 5 (ARC/WR5) were compared during 6 months intravenous immunoglobulin (IVIG) treatment (0.4 g/kg body weight every 2 weeks) with 15 placebo-treated patients. This study was aimed at the lymphocyte response to T and B cell mitogens and antigens. 3H-thymidine uptake was determined after stimulation with the unspecific mitogens phytohemagglutinin (PHA), pokeweed mitogen (PWM), formalinized Staphylococcus aureus-Cowan I (SAC), and with the antigens tuberculin and herpes simplex virus (HSV) at the onset, on days 85, 183, 267 and 351; IgG and IgM antibodies against HSV were measured by ELISA. In addition, 30 untreated HIV-negative controls were tested. For the T cell mitogen PHA, T-cell-dependent B cell mitogen PWM and B cell mitogen SAC, no differences between the two patient groups were observed before therapy nor in the course of therapy or the 6-month observation period thereafter. The entire patient group showed significantly impaired mitogenic response on day 1 as compared to the controls. There was no significant difference in response to tuberculin between the patients and HIV-negative controls, nor for both patients groups before and in the course of treatment. All patients had IgG antibodies against HSV. Three of them showed blastogenic lymphocyte response to HSV on day 1. Among 19 seropositive controls, 7 individuals showed positive HSV lymphocyte response; but for both patient groups, there was no significant difference before and in the course of the treatment and observation period.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Complex↗
PubMed1990

[Viral myocarditis and classical virology. Clinico-virologic and experimental data].

A viral etiology of myocarditis has been proven stringently only in a few cases and mostly enteroviruses have been shown to be involved. In fact, a virological diagnosis of viral myocarditis is still rarely possible today. Virus isolation from heart-tissue is hard to achieve and biopsies, if at all, are often performed too late. Successful virus isolation from other materials (e.g. faeces, throat swab) or a serological diagnosis of acute virus infection cannot easily be correlated etiologically with cardial symptoms, depending of course also on the kind of virus infection diagnosed. To prove an acute infection serologically a fourfold rise in antibody titer or for some viruses specific IgM has to be detected. A group specific diagnosis of "acute enterovirus infection" is not reliably possible at the moment. The neutralization test is the only relatively type specific test in enterovirus serology. Intraserotypic virus variants cannot be detected by normal serology. Even when determining neutralizing IgM-antibodies, interpretation of results raises problems due to long persistence and possible cross reactivity. In case of suspected viral myocarditis clinicians should institute early and broad virological diagnostic measures. Virologists have to establish methods for virus or antigen determinations by molecular biological means. Furthermore, a fast and easy serological method for the diagnosis of an "acute enterovirus infection' would be very helpful. For research on the pathogenesis established animal models have to be used.

Animals↗
PubMed1989

[Herpes virus infections in immunosuppressed patients. Herpes simplex and varicella zoster virus: prevention and therapy].

Herpes simplex virus (HSV) and varicella-zoster virus (VZV) giving rise to primary or recurrent infections still threaten immunocompromised patients. However, such prophylactic measures as passive and active immunisation against VZV infection, and antiviral chemoprophylaxis and chemotherapy of HSV- and VZV-infections have improved the prognosis of these patients considerably.

Chickenpox↗
PubMed1989

Re-implantation of homologous, cultivated osteoblast-like cells for improvement of bone regeneration. An animal study.

The regeneration of osseous tissues after implantation of rat osteoblast-like cells cultivated in vitro was investigated. A cell line of rat osteoblast-like cells originating from explants of four inbred rats (Lewis) was established. The osteoblast-like cells were cultivated in vitro and re-implanted after 3 passages in cell culture into artificial femur defects of the same inbred Lewis rats. The cultivated osteoblast-like cells were embedded in bovine bone gelatine and implanted together with hydroxylapatite granulate (12 animals), pyrolized calf bone (12 animals) or without any additional material (12 animals). These bone replacement materials were used as a carrier for the osteoblast-like cells. After 10, 20, 40 and 80 days animals were killed and the treated femora were taken for histological examination and determination of bone growth rate. It was demonstrated that the cultivated osteoblast-like cells in this experiment had no measurable effect on quantitative bone growth, but caused a significant difference in the histological bone regeneration pattern.

Animals↗
PubMed1989

[Comparative test of the soluble toxicity of hydroxyapatite ceramics using human and animal osteoblasts].

The soluble toxicity of 5 different hydroxylapatite granulates was tested in osteoblast cell cultures. We established a human osteoblast-like cell culture and a culture of rat (Lewis) osteoblast-like cells. The granulates were also tested in cultures of human gingival fibroblasts as a conventional system. It is demonstrated that the osteoblast-like cell cultures are of higher sensitivity than fibroblast cultures which do not show any reaction to the extracts of hydroxylapatite granulates. Only 2 hydroxylapatite granulates show some toxic. The human osteoblast-like cells reacted slightly more sensitive to toxic substances of the materials tested than rat osteoblast-like cells. It is demonstrated that the osteoblast-like cell cultures are a highly sensitive test system for materials with low toxicity.

Animals↗
PubMed1988

Chronic herpes simplex virus and varicella zoster virus infection.

After defining such terms as persistent and chronic infection, latency, recurrence, recrudescence, and exogenous reinfection they are applied to infections with HSV and VZV. Possible factors determining pathogenicity are discussed, and an overview is given of the wide range of illnesses and case reports ascribed to HSV and VZV infections. Various types of infection afford different diagnostic procedures. Besides virus isolation supplemented by viral antigen identification IgG antibody tests (increase in titer) may be useful. IgG subtype and IgA antibody determinations appear to be of limited value. Despite the rather large number of available tests, there are still considerable shortcomings in their ultimate significance as to the patient's disease. Thus, some new experimental approaches are mentioned.

Chickenpox↗
PubMed1988

[Specificity of first and second generation HIV-1 antibody screening tests].

Among 9867 sera tested between January and April 1987 by Abbott HTLV-III EIA (cell culture-derived antigen) 155 reacted repeatedly positive. 22% of these could not be confirmed, while 77% could be confirmed by other tests. The results of 2 sera remained equivocal. Subsequently Abbott recombinant HTLV-III EIA was used and until August of the same year 184 out of 11508 sera gave reproducible positive results. 12% of these could not be confirmed, while 86% could be confirmed. The results of 3 sera remained equivocal. False positive results were found in 0.34% of all sera examined by the test of the first generation, whereas the percentage in the second generation test was 0.19. Despite the higher specificity of the ELISA with antigen prepared by recombinant gene technology, there is further need for reliable confirmatory tests.

Antibody Specificity↗