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Biomedical subjects

D Aeppli

Publications and source records attributed to D Aeppli.

At least 37 records · Page 2Linked to original sources
PubMed1994

Bacteria as risk markers for periodontitis.

Specific microbial species have been closely associated with periodontitis. Through longitudinal studies, some of these microbial species have been implicated in the etiology of progressive periodontal disease. Although putative periodontal pathogens are often isolated from individuals with severe periodontitis, they also frequently inhibit the subgingival environment and are not always associated with advanced disease. In this respect, it is becoming increasingly apparent that there is no single etiology of the various periodontal diseases. Destructive periodontal diseases are the result of environmental, host, and bacterial factors. Microorganisms, however, are essential components of any model for progressive periodontitis. This paper selectively reviews bacteria as risk markers for periodontitis. Attention focuses on bacteria in conjunction with behavioral patterns (oral hygiene habits and smoking) and host response (gingival crevicular fluid substances) as risk markers for periodontitis. Prospective studies implicating specific bacteria in progressive periodontitis are addressed and a bacterial risk assessment model for progressive periodontitis is discussed with respect to the interplay between bacterial, environmental, and host markers.

Bacteria↗
PubMed1994

Sensitivity of primary clonogenic blasts from acute lymphoblastic leukemia patients to an activated cyclophosphamide, viz., mafosfamide.

Primary cyclophosphamide-naive clonogenic blasts from 32 patients with newly diagnosed acute lymphoblastic leukemia (ALL) were tested for their in vitro sensitivity to an "activated" cyclophosphamide, viz., mafosfamide, using leukemic progenitor cell (LPC) colony assays. Marked interpatient variation in the responses of LPC from newly diagnosed patients to mafosfamide prompted assessment of mafosfamide sensitivity in relation to more frequently measured parameters of newly diagnosed ALL. Only immunophenotype and sex showed a significant association with the intrinsic mafosfamide sensitivity of LPC. LPC from T-lineage ALL patients were more resistant to mafosfamide than LPC from B-lineage ALL patients, as reflected by 1.8-fold and 4.3-fold higher mean SF10 and SF20 (surviving fractions of ALL LPC of 10 and 20 microM mafosfamide, respectively) values. LPC from male patients were more resistant to mafosfamide than LPC from female patients, as reflected by 1.9-fold and 4.8-fold higher mean SF10 and SF20 values. In comparison to T-lineage ALL patients, a significantly greater fraction of B-lineage ALL patients had mafosfamide-sensitive LPC with SF10 values of < 0.25 (61% vs 11%, P = 0.01). Notably, all four cases exhibiting resistance to mafosfamide, i.e., SF20 > or = 0.5, were males with T-lineage ALL. In order to exclude the influence of sex as a confounding factor in the observed immunophenotype-mafosfamide sensitivity association, we also compared the mafosfamide sensitivities of LPC from male patients only. The means of SF10, and SF20 values of LPC from male T-lineage ALL patients were 1.5- and 3.2-fold higher than those of LPC from male B-lineage ALL patients (P < 0.1). Thus, in the male patient subgroup, the immunophenotype-mafosfamide sensitivity association remained significant.

Adjuvants, Immunologic↗
PubMed1993

Radiation resistance of primary clonogenic blasts from children with acute lymphoblastic leukemia.

PURPOSE: Detailed comparative analyses of the radiation sensitivity of primary clonogenic blasts from children with acute lymphoblastic leukemia (ALL) were performed to achieve a better understanding of clinical radiation resistance in ALL. METHODS AND MATERIALS: The radiation sensitivity of primary clonogenic blasts from 74 children with newly diagnosed acute lymphoblastic leukemia (ALL) was analyzed using leukemic progenitor cell (LPC) assays. Primary bone marrow blasts from all 74 patients were exposed to ionizing radiation and subsequently assayed for LPC-derived blast colony formation. Radiation survival curves of primary clonogenic blasts (i.e., LPC) were constructed for each of the newly diagnosed patients using computer programs for the single-hit multitarget as well as the linear quadratic models of cell survival. RESULTS: A marked interpatient variation in intrinsic radiation sensitivity was observed between LPC populations. The SF2 values ranged from 0.01 to 1.00 (median: 0.36; mean +/- SE = 0.40 +/- 0.03), and the alpha values ranged from 0.00 Gy-1 to 3.27 Gy-1 (median: 0.280 Gy-1; mean +/- SE = 0.43 +/- 0.09 Gy-1). Patients were divided into groups according to their sex, age, WBC at diagnosis, cell cycle distribution of leukemic blasts, and immunophenotype. Only immunophenotype provided a significant correlation with the intrinsic radiation sensitivity of LPC. Patients with B-lineage ALL had higher SF2 (0.47 +/- 0.04 vs. 0.31 +/- 0.05, p < 0.05) and smaller alpha values (0.43 +/- 0.09 Gy-1 vs. 0.65 +/- 0.10 Gy-1, p < 0.05) than T-lineage ALL patients, consistent with greater intrinsic radiation resistance at the level of LPC. Notably, 43% of B-lineage ALL cases, but only 27% of T-lineage ALL cases had LPC with SF2 > or = 0.5. Similarly, 66% of B-lineage ALL cases, but only 37% of T-lineage ALL cases had LPC with alpha values < or = 0.4 Gy-1. Combining the two indicators of radiation resistance, we found that only 34% of the B-lineage ALL patients had none of the two parameters in the respective critical regions (alpha < or = 0.4 Gy-1; SF2 > or = 0.5), while 63% of the T-lineage patients had none (p < 0.05). In multivariate analyses, the immunophenotypic B-lineage affiliation was the only significant predictor of radiation resistance at the level of LPC. Whether alone or in combination, none of the other variables examined, including sex, age, WBC, in vitro plating efficiency, S-phase index, and proliferation index were significantly correlated with the radiation sensitivity or resistance of LPC. CONCLUSION: These results offer unprecedented evidence for an association between composite immunophenotype (viz., B-lineage ALL vs T-lineage ALL) and radiation resistance that may form a basis for modifying radiation conditioning regimens.

Adolescent↗
PubMed1992

The role of radiation therapy in Hodgkin disease: experience and controversy. The 54th annual Janeway Lecture: 1989.

BACKGROUND: Beginning in 1970, a series of patients with Hodgkin disease were treated at the University of Minnesota, after staging laparotomy, with radiation therapy (RT) for Stage I, II, and IIIA Hodgkin disease. This report is an analysis of the results of the treatment and of treatment modifications. METHODS: From 1970 to 1974, all patients were treated with standard RT. In 1975, an analysis of these patients indicated that patients with large mediastinal mass (LMM) and patients with Stage IIIA spleen-positive (IIIAS+) disease had a higher recurrence rates than patients without these factors. Subsequently, a schema of radical radiation therapy (RRT) was devised, which included low-dose lung RT for patients with LMM and low-dose liver RT for patients with IIIAS+ disease. RESULTS: Analysis of the results of the two treatments indicates that the use of low-dose lung RT in patients with LMM and low-dose liver RT in patients with IIIAS+ Hodgkin disease produced survival and recurrence-free survival results equivalent to those achieved by use of combined modality treatment (CMT) or chemotherapy (CT) alone. CONCLUSIONS: The use of RT with whole lung and liver irradiation for patients with LMM and IIIAS+ Hodgkin disease, respectively, produces results that are equivalent to those of CMT or CT alone with the advantage of a decreased incidence of second malignant neoplasms. In addition, patients who do not respond to initial RT have a greater chance of being saved with chemotherapy than do patients initially treated with CMT of being saved with RT. The authors suggest that radical RT is the treatment of choice for patients with LMM and/or IIIAS+ Hodgkin disease.

Adolescent↗
PubMed1992

Sensitive microculture method for isolation of human immunodeficiency virus type 1 from blood leukocytes.

A study was conducted to compare our standard culture with a new microculture procedure for isolation of human immunodeficiency virus type 1 (HIV-1) from blood leukocytes. A total of 137 blood specimens from 102 HIV-1 antibody-positive individuals (52 were asymptomatic, 31 were symptomatic, and 19 had AIDS) were cultured in a microculture system in which 10(6) of the patients' peripheral blood mononuclear cells (PBMC) were cocultured with 10(6) phytohemagglutinin (PHA)-stimulated PBMC from an HIV-1 antibody-negative blood donor in 1.2 ml of culture medium. Results were compared with those of a historical control group of 139 standard HIV-1 cultures from 108 HIV-1 antibody-positive subjects (58 were asymptomatic, 36 were symptomatic, and 14 had AIDS). For standard cultures, 10 x 10(6) of the patients' PBMC were cocultured with 5 x 10(6) PHA-stimulated PBMC from an HIV-1 antibody-negative blood donor in 15 ml of culture medium. HIV-1 was isolated in 128 (93%) microcultures and 133 (96%) standard cultures. Both methods identified more than 75% of the positive cultures within 7 days and 100% of the positive cultures within 14 days. The isolation rates for HIV-1 in microcultures compared with standard cultures were 91 versus 93% (specimens from asymptomatic individuals), 93 versus 96% (specimens from symptomatic individuals), and 97 versus 100% (specimens from patients with AIDS). The median time to positivity for both culture methods was 7 days, and this correlated significantly with symptoms and CD4+ cell counts. The microculture method is a sensitive and less expensive system for isolation of HIV-1 from PBMC of HIV-1 antibody-positive individuals, and we recommend it as the culture method of choice, especially for children and patients with AIDS and severe anemia or leukopenia whose blood volume is an important consideration.

Evaluation Studies as Topic↗
PubMed1992

Minocycline slow-release formulation effect on subgingival bacteria.

The purpose of this study was to determine the microbiological efficacy of an adjunctive minocycline periodontal formulation delivered subgingivally. Subjects were systemically healthy but exhibited severe periodontitis; i.e., probing depths greater than 6 mm. The two study groups included individuals who received minocycline or a placebo periodontal formulation after root planing. Subgingival plaque samples were obtained at baseline; prior to treatment; and at 1, 3, and 6 months. Plaque was evaluated by darkfield microscopy and further analyzed for total dark-pigmented Bacteroides species, P. intermedia, P. gingivalis and Streptococcus, Actinomyces, Eikenella, Actinobacillus, Capnocytophaga, and Fusobacterium species using cultivable flora techniques. In addition, plaque was evaluated for yeast on a selective agar medium. When compared to the placebo, the minocycline group had significantly lower proportions of spirochetes at 1 and 3 months and lower proportions of motile rods at 3 months. Furthermore, when compared to the placebo group, the minocycline patients had lower mean proportions of dark-pigmented Bacteroides spp. and P. intermedia at 1 and 3 months as well as lower proportions of E. corrodens at 1 month. The minocycline group had significant decreases in proportions of spirochetes at 1 and 3 months, motile rods at 1 and 3 months, and increases in cocci at 1, 3, and 6 months when compared to baseline. In the placebo group, root planing was also effective at decreasing spirochetes at 1, 3, and 6 months, but with significant differences seen only at 3 and 6 months. However, the degree of reduction in spirochete proportions was greater in the minocycline group when compared with the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗
PubMed1991

Pathophysiology of Streptococcus pneumoniae otitis media: kinetics of the middle ear biochemical and cytologic host responses.

Streptococcus pneumoniae is an important bacterial pathogen in the pathophysiology of otitis media. To elucidate the inflammatory responses that occur during pneumococcal otitis media, the kinetics of the biochemical and cytologic middle ear responses to heat-killed encapsulated and nonencapsulated pneumococci were studied in the chinchilla model. Inoculation of the middle ear cavity with at least 10(6) S pneumoniae cells induced an early, brief vascular response with leakage of small (albumin) followed by larger (alpha 2-macroglobulin) proteins, followed by sustained influx of acute inflammatory cells and lysozyme. The threshold for a sustained lysozyme response was 1,000 times lower for nonencapsulated than for encapsulated pneumococci. These results indicate that nonviable S pneumoniae organisms with an intact envelope initiate the middle ear inflammatory response. Therefore, interventions that enhance the clearance of pneumococcal cells from the middle ear may reduce the inflammatory response and prevent chronic middle ear inflammation.

Albumins↗
PubMed1991

Periodontal findings in adult twins.

Gingivitis and periodontitis are among the most common diseases known to man. Although bacterial plaque is generally accepted as the primary etiologic agent, little information is available concerning the influence that host genetic factors have on these diseases. The purpose of the present study was to examine the relative contribution of environmental and host genetic factors to clinical measures of periodontal disease through the study of both reared-together twins and monozygous twins reared apart. Probing depth, clinical attachment loss, gingivitis, and plaque were assessed from the Ramfjord teeth in 110 pairs of adult twins (mean age 40.3 years), including 63 monozygous and 33 dizygous twin pairs reared together and 14 monozygous twin pairs reared apart. Bootstrap sampling was used to estimate and provide confidence limits of between-pair and within-pair variances, intraclass correlations and heritability. Based on ratios of within-pair variances or heritability estimates, a significant (P less than 0.05) genetic component was identified for gingivitis, probing depth, attachment loss and plaque. Heritability estimates indicated that between 38% to 82% of the population variance for these periodontal measures of disease may be attributed to genetic factors. While there is general agreement that bacteria are important in the pathogenesis of the periodontal diseases, future etiologic studies should consider the role of host genetic influences.

Adolescent↗
PubMed1990

Comparison of measurement variability using a standard and constant force periodontal probe.

This study compared the intra- and inter-examiner reliability of the Florida Probe, Florida Disk Probe, and conventional periodontal probe. Using these instruments, each of three examiners made repeated measurements of probing depth (using the Florida Probe and conventional probe), relative attachment level (using the Florida Disk Probe), and clinical attachment level (using a conventional probe) at posterior, proximal sites in 10 subjects with early periodontitis. The mean intra-examiner standard deviation of differences in repeated probing depth measurements ranged from 0.46 to 0.77 mm demonstrating similar levels of reproducibility between the Florida Probe and conventional probe. The mean intra-examiner standard deviation of differences in repeated relative attachment level measurements using the Florida Disk Probe ranged from 0.44 to 0.57 mm using double passes and from 0.98 to 1.41 mm using single passes of measurements. For clinical attachment level measurements obtained using single passes of measurements with a conventional probe, the mean intra-examiner standard deviation of differences ranged from 0.78 to 0.95 mm. Inter-examiner variability was generally greater than intra-examiner variability for all instruments. It was concluded that double passes with the Florida Disk Probe offers significant advantages for measuring relative attachment level in longitudinal studies of early periodontitis when decisions for change must be made as soon as possible.

Bias↗
PubMed1990

Hodgkin's disease in children: correlation of clinical characteristics, staging procedures, and treatment at the University of Minnesota.

The cases of 63 children treated for Hodgkin's disease were retrospectively evaluated according to clinical and laboratory characteristics at initial appearance, clinical and pathologic staging, and treatment for their effects on survival and disease-free survival. An initial erythrocyte sedimentation rate over 50 mm/h was common in patients who ultimately had a relapse. There was no correlation between the size of the mediastinal mass at diagnosis and occurrence of relapse. A residual mediastinal mass was found in 22% of patients after 1 year of treatment regardless of its size at initial appearance. With a median follow-up time of 10.5 years, the overall survival rate is 89%, and disease-free survival rate is 71%. The disease-free survival rates for patients with stages I-IV disease are 92, 81, 78, and 40%, respectively. Relapses occurred in 7 of 22 (36%) patients with positive staging laparotomy despite radiotherapy for three with stage IA and IIA disease, chemotherapy alone for two with stage IIIB disease, or chemotherapy for one with stage IIIB and one with stage IVB disease. Of patients who had no evidence of abdominal Hodgkin's disease at a staging laparotomy, 6 of 34 (19%) had a relapse. These included one with stage IA and five stage IIA disease, all treated with radiotherapy alone. Treatment of stage III and IV disease with regimens including CCNU (lomustine) or cyclophosphamide, plus vinblastine sulfate or vincristine sulfate, prednisone, and procarbazine hydrochloride with or without radiation therapy yielded poor results, with 6/7 having a relapse.

Adolescent↗
PubMed1989

Public health implications of the variability in the interpretation of 'B' readings for pleural changes.

During 1985 in Minnesota, an initial reading of 566 radiographs found 30% of them to be positive for pleural changes. However, only 4% were considered positive by at least two out of three readers from National Institute for Occupational Safety and Health panel reading the radiographs under blind conditions. The implications of this variability in radiographic readings for public health decisions was illustrated in Minnesota, where selective overreading of radiographs of female subjects created an illusion of a generalized environmental problem rather than an occupational exposure. One solution to this dilemma is establishment of criteria to minimize false-positive pleural findings. The study also supports the need for more careful consideration of other disease processes in the interpretation of "B" readings.

False Negative Reactions↗
PubMed1988

The contribution of pneumococcal cell wall to the pathogenesis of experimental otitis media.

We studied the contribution of pneumococcal cell wall to the pathogenesis of otitis media in chinchillas after middle ear inoculation of killed, encapsulated type 7F Streptococcus pneumoniae; killed, unencapsulated R6 S. pneumoniae; and isolated R6 pneumococcal cell wall. Ears inoculated with encapsulated and unencapsulated pneumococci had significantly higher concentrations of polymorphonuclear and mononuclear leukocytes and lysozyme in middle ear fluid and developed more epithelial metaplasia and granulation tissue than did saline-inoculated ears. The mean concentration of lysozyme in middle ear fluid was higher in ears inoculated with killed, unencapsulated than encapsulated pneumococci. The middle ear mucoperiosteum of ears inoculated with pneumococcal cell wall showed significantly more polymorphonuclear leukocytes, epithelial metaplasia, subepithelial congestion, and granulation tissue than did control ears. Because nonviable, unencapsulated pneumococci and pneumococcal cell wall caused middle ear inflammation in the chinchilla model of otitis media, it is possible that cell envelope and cell wall components released during bacterial lysis may contribute to chronic otitis media with effusion in humans.

Acute Disease↗
PubMed1988

The consensus statements on adjuvant chemotherapy in breast cancer. Fact or artifact.

The decision of the National Cancer Institute, in November of 1985, in favor of adjuvant chemotherapy in the treatment of the premenopausal patient was based on the analysis of randomized clinical trials. The authors have carefully evaluated five papers dealing with the trials and found in each of them some problem in the performance or statistics which makes us question the interpretation of the findings of a statistically significant advantage for adjuvant chemotherapy in premenopausal patients. In view of this, we suggest that all the studies being considered need to be checked for their validity and if a significant number have similar flaws to those in the five trials noted, then we suggest that it is not possible to come to conclusions reported by the consensus panel.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Association between signs of trauma from occlusion and periodontitis.

The purpose of this study was to evaluate the association between signs of trauma from occlusion, severity of periodontitis and radiographic record of bone support. The maxillary first molars of 300 individuals were independently evaluated by two examiners for signs of trauma from occlusion, pattern or occlusal contacts and severity of periodontitis. Each site was also evaluated radiographically by an independent third examiner. The results indicated that: teeth with either bidigital mobility, functional mobility, a widened periodontal ligament space or the presence of radiographically visible calculus had a deeper probing depth, more loss of clinical attachment and less radiographic osseous support than teeth without these findings, teeth with occlusal contacts in centric relation, working, nonworking or protrusive positions did not exhibit any greater severity of periodontitis than teeth without these contacts, teeth with both functional mobility and radiographically widened periodontal ligament space had deeper probing depth, more clinical attachment loss and less radiographic osseous support than teeth without these findings and given equal clinical attachment levels, teeth with evidence of functional mobility and a widened periodontal ligament space had less radiographic osseous support than teeth without these findings.

Adult↗
PubMed1983

Acyclovir halts progression of herpes zoster in immunocompromised patients.

We conducted a placebo-controlled, double-blind study of acyclovir therapy for acute herpes zoster in immunocompromised patients. Of the 94 patients enrolled in the study, 52 had localized skin lesions at entry, and 42 had disseminated cutaneous zoster. A one-week course of intravenous acyclovir (1500 mg per square meter of body-surface area per day) halted progression of zoster in both groups, as determined by development or progression of cutaneous dissemination, development of visceral zoster, or proportion of cases deemed treatment failures. Significantly fewer patients treated with acyclovir within the first three days after the onset of exanthem had complications of zoster, as compared with patients treated with placebo (P = 0.02 by Fisher's exact test), but acyclovir also stopped progression of zoster in patients treated after three days of rash (P = 0.05 by Fisher's exact test). Acyclovir recipients with disseminated cutaneous zoster had a significantly accelerated rate of clearance of virus from vesicles, as compared with placebo recipients (P = 0.05 by the Breslow test).

Acyclovir↗
PubMed1983

Acyclovir in shingles.

Acyclovir given intravenously in either low dose (5 mg/kg every 8 h) or high dose (500 mg/m2 every 8 h) significantly reduced pain and accelerated skin healing in acute herpes zoster occurring in otherwise healthy adults. The higher dose also significantly reduced the duration of viral shedding. No significant effect on post-herpetic neuralgia could be demonstrated, although the higher dose showed a promising trend. No adverse effects were associated with the lower dose, but acyclovir at 500 mg/m2 resulted in nausea, vomiting and transiently elevated serum creatinine in a substantial number of patients.

Acyclovir↗