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Biomedical subjects

J H Meurman

Publications and source records attributed to J H Meurman.

At least 55 records · Page 3Linked to original sources
PubMed1998

Surface structure, hydrophobicity, phagocytosis, and adherence to matrix proteins of Bacillus cereus cells with and without the crystalline surface protein layer.

Nonopsonic phagocytosis of Bacillus cereus by human polymorphonuclear leukocytes (PMNs) with particular attention to bacterial surface properties and structure was studied. Two reference strains (ATCC 14579(T) and ATCC 4342) and two clinical isolates (OH599 and OH600) from periodontal and endodontic infections were assessed for adherence to matrix proteins, such as type I collagen, fibronectin, laminin, and fibrinogen. One-day-old cultures of strains OH599 and OH600 were readily ingested by PMNs in the absence of opsonins, while cells from 6-day-old cultures were resistant. Both young and old cultures of the reference strains of B. cereus were resistant to PMN ingestion. Preincubation of PMNs with the phagocytosis-resistant strains of B. cereus did not affect the phagocytosis of the sensitive strain. Negatively stained cells of OH599 and OH600 studied by electron microscopy had a crystalline protein layer on the cell surface. In thin-sectioned cells of older cultures (3 to 6 days old), the S-layer was observed to peel off from the cells. No S-layer was detected on the reference strains. Extraction of cells with detergent followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a major 97-kDa protein from the strains OH599 and OH600 but only a weak 97-kDa band from the reference strain ATCC 4342. One-day-old cultures of the clinical strains (hydrophobicity, 5.9 to 6.0%) showed strong binding to type I collagen, laminin, and fibronectin. In contrast, reference strains (hydrophobicity, -1.0 to 4.2%) as well as 6-day-old cultures of clinical strains (hydrophobicity, 19.0 to 53.0%) bound in only low numbers to the proteins. Gold-labelled biotinylated fibronectin was localized on the S-layer on the cell surface as well as on fragments of S-layer peeling off the cells of a 6-day-old culture of B. cereus OH599. Lactose, fibronectin, laminin, and antibodies against the S-protein reduced binding to laminin but not to fibronectin. Heating the cells at 84 degreesC totally abolished binding to both proteins. Benzamidine, a noncompetitive serine protease inhibitor, strongly inhibited binding to fibronectin whereas binding to laminin was increased. Overall, the results indicate that changes in the surface structure, evidently involving the S-layer, during growth of the clinical strains of B. cereus cause a shift from susceptibility to PMN ingestion and strong binding to matrix and basement membrane proteins. Furthermore, it seems that binding to laminin is mediated by the S-protein while binding to fibronectin is dependent on active protease evidently attached to the S-layer.

Bacillus cereus↗
PubMed1998

Periodontal findings in elderly patients with non-insulin dependent diabetes mellitus.

The periodontal status of 25 patients with non-insulin dependent diabetes mellitus (NIDDM) (age range 58 to 76) was investigated and compared with 40 non-diabetic control subjects (age range 59 to 77). Surfaces with visible plaque and bleeding after probing, calculus, recessions, and pathological pockets were examined. The total attachment loss was calculated as a sum of recessions and pockets in millimeters. Mesial and distal bone loss was measured from panoramic radiographs and mean alveolar bone loss was calculated. Periodontal disease was considered advanced when mean alveolar bone loss was over 50%, or 2 or more teeth had pockets > or = 6 mm. Microbiological analysis comprised the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides forsythus by a polymerase chain reaction (PCR) method. Patients with NIDDM had significantly more often advanced periodontitis than control subjects, 40.0% and 12.5%, respectively. Diabetic patients did not harbor more pathogens than the control subjects. The HbA1C level deteriorated in patients with advanced periodontitis, but not in other patients with NIDDM, when compared to the situation 2 to 3 years earlier. Advanced periodontitis seems to be associated with the impairment of the metabolic control in patients with NIDDM, and a regular periodontal surveillance is therefore necessary.

Aged↗
PubMed1997

Oral sources of septicaemia in patients with malignancies.

This article reviews papers dealing with oral infections of adult septicaemia patients, searched from MEDLINE, Current Contents and Core Biomedical Collection databases from January 1966 to November 1996. Case reports were excluded. The systematic review of literature revealed that our knowledge of the topic is mostly based on very small patient material. There are no multicentre studies on the effects of various oral health treatment modes on the prevention of septicaemia of oral origin. The number of controlled and comparative studies on the efficacy of the different treatment protocols of oral infections is also small. Current recommendations in this respect are mainly empirical and not evidence based. Clinical practice guidelines are therefore urgently needed. Nevertheless, close co-operation between oncological and oral health units is emphasised because many studies have shown that the oral cavity is indeed an important source of bacteraemia. Life-threatening infections may follow if maintenance of oral health is neglected during anticancer therapy and if potential oral infection foci are left untreated before immunosuppressive therapy.

Adult↗
PubMed1997

Five-year follow-up study of saliva, mutans streptococci, lactobacilli and yeast counts in lymphoma patients.

Twenty-two patients out of the 79 that were originally included were examined 5 years after beginning anticancer therapy for lymphomas. The patients' cumulative data on salivary flow rate, buffering capacity and acidogenic microbial counts were compared with respective data of 17 patients who died during the follow-up. Stimulated saliva samples had been taken at baseline and during the cytostatic treatment with combination chemotherapy, and 1 year and 5 years later. Chair-side kits were used at the hospital ward for the assessment of the study parameters. Mean saliva flow at baseline was 1.5 +/- 0.7 ml/min in the surviving group and 1.5 +/- 0.8 ml/min in the deceased. Salivary flow rates were not affected by the anticancer treatment and there was no statistically significant difference between the groups in this respect. A significant difference was observed between the groups in salivary buffering capacity values at baseline: only 32% of the survived had low buffering capacity in comparison to 69% of those who later died (P < 0.02). Buffering capacity values remained low in 50% of the surviving patients 5 years later. Higher mutans streptococci and lactobacilli counts were seen among the deceased than in the survived patients but mutans streptococci decreased significantly in both groups after the start of the anticancer therapy (P < 0.05). The number of positive yeast counts increased consistently during the chemotherapy in both groups, being higher in the survived when compared with the deceased patients. Yeast counts remained positive 5 years later in 73% of the survived patients, while the mean mutans streptococci and lactobacilli counts decreased below baseline values. The results showed that persistently high salivary microbial counts and low buffering capacity may be linked with poor prognosis.

Adult↗
PubMed1997

Five-year follow-up of saliva in patients treated for lymphomas.

OBJECTIVE: Patients treated for Hodgkin's disease and non-Hodgkin lymphomas were followed for 5 years after start of therapy. The patients received combinations of anticancer drugs for curative intent for 6 months (Hodgkin's disease) or 7 months (non-Hodgkin lymphomas). STUDY DESIGN: Cumulated data of 22 surviving patients (mean age, 49 years) were compared with that of 17 patients (mean age, 52 years) who had died or were terminally ill at the 5-year examination. Saliva samples were taken at baseline, and 4, 6, 12, and 60 months after start of chemotherapy. Salivary flow rate and a variety of biochemical constituents were analyzed. RESULTS: The results showed no long-term effect of anticancer treatment on salivary flow rates. Neither was there any difference between the surviving or deceased patients' baseline values (1.5 +/- 0.7 mL/minute versus 1.5 +/- 0.8 mL/minute) and after chemotherapy. Lysozyme, IgA, IgG, and IgM concentrations decreased after chemotherapy. Significantly lower values were observed at the 5-year examination than at baseline. This was particularly evident in IgA, which is the major immunoglobulin in saliva; mean IgA was 70.5 +/- 52.8 mg/mL at baseline, 35.8 +/- 15.0 mg/mL 5 years later (p < 0.001). Salivary total protein and amylase concentrations were significantly decreased (p < 0.001 and p < 0.05, respectively), whereas albumin concentration was significantly increased at the 5-year examination (p < 0.05). When the salivary biochemical results were compared between the surviving and deceased patients, no statistically significant differences were observed. At baseline, however, the mean immunoglobulin values were lower in patients who later died, in comparison with those who survived. CONCLUSIONS: These results showed that modern anticancer therapy need not cause severe side effects on salivary flow rates and composition. In addition, apart from the long-term immunosuppression, no significant decreases were expressed in salivary defensive factors.

Adult↗
PubMed1997

Salivary flow and composition in elderly patients referred to an acute care geriatric ward.

OBJECTIVE: The purpose of this investigation was to study oral health and salivary aspects of the frail elderly. The study hypothesis was that elderly patients with many concomitant diseases and drugs would have different salivary secretion rates and biochemical constituents than healthier patients. STUDY DESIGN: The stimulated flow, pH buffering capacity, and biochemical constituents were analyzed from salivas of 169 elderly subjects (51 men and 118 women, mean age 81.2 years, range 69 to 96 years) admitted to an acute geriatric ward because of sudden worsening of their health. Common statistical methods were used to analyze the differences among patient groups. The patients were grouped according to the number of concomitant diseases and daily used drugs and on the basis of salivary flow rate values. RESULTS: Reduced salivary flow (< 0.7 ml/min) was found in 48% of the men and 62.5% of the women, and a low buffering capacity was found in 31.9% of the men and 36.7% of the women. Age did not significantly affect the salivary flow rate. The factors that showed the strongest influence on salivary flow were endocrinologic diseases, ophthalmologic and respiratory drugs, and potassium chloride. Salivary immunoglobulin A and immunoglobulin M concentrations were significantly higher in older patients. Immunoglobulin A, lysozyme, and amylase concentrations were significantly higher in older patients taking many drugs. Patients with many concomitant diseases had significantly higher salivary urea concentrations than healthier patients. Edentulous patients had significantly higher salivary immunoglobulin A, immunoglobulin M, lysozyme, and amylase concentrations. CONCLUSIONS: In this study, hyposalivation was a frequent observation, and the elderly who took many drugs and had several systemic diseases had higher concentrations of most of the analyzed biochemical constituents.

Aged↗
PubMed1997

Transformation of hydroxyapatite to fluorapatite by irradiation with high-energy CO2 laser.

High-energy laser irradiation has been shown to cause crystalline transformations in apatites, which may lead to the formation of tricalcium phosphates with a resulting decrease in acid resistance. Depending on the nature and energy density of laser irradiation used, however, an increase of acid resistance of dental enamel has also been reported after laser irradiation. The aim of the present study was to investigate the phase transformation of hydroxyapatite (HA) to fluorapatite (FA) in a model system that incorporates sodium fluoride (NaF) into apatite structure by using laser irradiation. A CO2 laser was used at energy densities ranging from 21 to 500 J/cm2. Synthetic HA mixed with NaF (10:1) was the target of laser irradiation. The crystalline structures were then investigated using X-ray diffraction analysis. The results showed that a phase transformation of HA to FA could be realized, and that the threshold energy density needed was 38 J/cm2. Not only is the finding crystallographically important, but it also opens new perspectives for future research regarding the development of laser technology for clinical purposes.

Apatites↗
PubMed1997

Oral infections in home-living elderly patients admitted to an acute geriatric ward.

Little is known about the oral health of the frail and home-living elderly. The effects of dentogenic infections on the general condition of the elderly are also unknown. We therefore set out to investigate 191 elderly patients referred to an acute geriatric hospital due to sudden worsening of their general health. The patients' mean age was 81.2 +/- 6.4 years (range, 67 to 96 years), and they had lived at home before hospitalization. The patients were examined and their diagnoses set by a team of physicians. The dentist's examination was also made bedside. Panoramic x-rays were taken for those who were able to stand (n = 148). Particular attention was paid to the occurrence of dental infection foci and systemic infection parameters of blood. Only patients free from other than dental infections were included in the statistical analyses (n = 184). Panoramic x-rays revealed dentogenic infection foci in 71.1% of the dentate patients. Periodontal condition was poor in 96.2% of the patients (CPI score, 2 to 4). All infection parameters were high in patients with high periodontal treatment need, but the differences were not statistically significant. Neither were there statistically significant correlations between the number of dentogenic infection foci recorded from the radiographs and infection parameters of blood. More of the edentulous patients had positive salivary yeast counts than did the dentate patients (84.4% vs. 66.1%; P < 0.05). No correlation was found between the main systemic diagnoses and dental infections. Since the prevalence of dentogenic infection foci in our subjects was high, and they did not cause marked increase in the hematological infection parameters investigated, it seems clear that geriatricians should refer their patients for dental examinations. Although our patients represent the home-living elderly population in a Nordic country with a high standard of living and good medical care, dental care had been neglected regardless of the patients' systemic disease.

Acute Disease↗
PubMed1997

Identification of Bacteroides forsythus in subgingival dental plaque with the aid of a rapid PCR method.

Bacteroides forysthus has been shown to be prevalent among patients with periodontitis. Conventional microbiological methods used to identify this bacterium, however, are laborious and time-consuming and are therefore not well-suited for screening purposes. We have developed a polymerase chain-reaction (PCR) method which is rapid, specific, and simple to perform and does not require other sample pre-treatment except a brief centrifugation. This method was applied to the detection of B. forsythus in subgingival plaque of 58 periodontitis patients. When compared with the results of conventional culturing, the PCR method always confirmed the culture-positive results, while none of the PCR negative samples was shown to be culture-positive. The PCR method appeared to give more than double the number of samples positive for B. forsythus than culturing (89.7% vs. 37.9%). The analysis requires less than 4 hrs to perform, and is specific only to B. forsythus and sensitive enough to detect fewer than 5 bacteria.

Adult↗
PubMed1997

[Fifty years of dental nurse education in Finland].

The first training-course for dental nurses was arranged by the Finnish Dental Association in 1947-1948. Professional help was needed in dental offices in assisting the dentists, taking care of the patients, particularly children, and in cleaning the equipment. As early as 1922 the Scandinavian Dental Association had pointed out that "clinic sisters" would be needed in dental training centers, but the suggestion was not put into effect. The first nine-month curriculum for dental nurses already included all disciplines of dentistry. Lectures in pharmacology, bacteriology and first-aid were also given. Practical training was arranged at the Institute of Dentistry, University of Helsinki. The students further trained for three-week periods both at dental clinics and at privat dental offices. Nine students completed the course and received their diplomas at the end of May, 1948.

Dental Assistants↗
PubMed1997

Dental infections and general health.

The detrimental effect of focal infection on general health has been known for decades. Chronic dental infections may worsen the condition of medically compromised patients. Prophylactic antibiotics are therefore routinely prescribed before dental treatment to immunosuppressed and other at-risk patients to combat the spread of oral bacteria into the bloodstream. More recent studies have shown that dental infections may also be a risk factor for atherosclerosis and various other chronic diseases, emphasizing the need for frequent dental checkups among the diseased, in particular. The aim of this review article is to discuss some recent findings on the effect of dental infections on health in general. In many industrialized countries, there is an urgent need to focus on preventive dental care for the diseased and the elderly, whose oral health has been more or less neglected.

Antibiotic Prophylaxis↗
PubMed1996

Pericoronitis and tonsillitis: clinical and darkfield microscopy findings.

OBJECTIVE: Upper respiratory tract infections and tonsillitis and pharyngitis in particular increase the risk of lower third molar pericoronitis. The study was made to investigate clinical and microbiologic associations between pericoronitis and tonsillitis. STUDY DESIGN: The subjects were 20-year-old Finnish male conscripts. Thirty-eight patients had tonsillitis without and 33 patients had tonsillitis with a symptom-free erupting lower third molar; 27 patients had pericoronitis but healthy tonsils. All subjects were examined clinically. Bacterial samples were taken from healthy and diseased tonsils and from healthy and diseased third molar pericoronal pockets. The microbes were classified morphologically with the use of a darkfield microscope. RESULTS: Eighty-two percent of infected tonsils had deep crypts and 52% of them exudated pus compared with 36% (p < 0.001) and 0% (p < 0.001) in healthy tonsils, respectively. Infected lower third molars were less than half erupted and had on average 8.8 mm deep pericoronal pockets compared with pockets 5.5 mm deep recorded in symptom-free cases (p < 0.001). Spirochetes were more common in infected pockets than in symptom-free cases comprising 8.2% versus 3.0% of the total bacterial count (p = 0.044). Rods were more common in infected tonsils than healthy ones (8.9% versus 4.8%, p = 0.041). CONCLUSION: There were similarities in morphologic microbiota of pericoronitis and tonsillitis. However, clinical findings of tonsils did not appear to link with the findings of third molars.

Adult↗
PubMed1996

Bacteriologic findings in tonsillitis and pericoronitis.

Bacteriologic samples from 31 young men were cultured quantitatively for aerobes and anaerobes; these samples included 31 specimens of tonsils (16 infected and 15 healthy), 16 specimens from pericoronal pockets of lower third molars (11 infected and 5 symptom-free), and 6 postoperative specimens from lower-third-molar extraction sockets. Anaerobes were isolated more often from infected third molars than from infected tonsils (14.5 isolates vs. 8.4 isolates, respectively; P < .001). Infected tonsil samples contained significantly more anaerobic species if an adjacent partly erupted lower third molar was present rather than absent (10.3 isolates vs. 6.9 isolates, respectively; P < .05). Eubacterium aerofaciens, Clostridium species, Peptostreptococcus micros, and Prevotella oris were frequently isolated. Streptococcus salivarius was found more frequently in tonsillar specimens, whereas Corynebacterium species, Prevotella denticola, Capnocytophaga species, Peptostreptococcus anaerobius, and Lactobacillus species were more common in pericoronal pocket samples. Thus, partial eruption of lower third molars increases the number of anaerobic bacterial species on tonsils and many species can be isolated simultaneously from both tonsils and lower third molars.

Adolescent↗
PubMed1996

Pathogenesis and modifying factors of dental erosion.

Dental erosion is caused by acidic solutions which come into contact with the teeth. Because the critical pH of dental enamel is approximately 5.5, any solution with a lower pH value may cause erosion, particularly if the attack is of long duration, and repeated over time. Saliva and salivary pellicle counteract the acid attacks but if the challenge is severe, a total destruction of tooth tissue follows. Ultrastructural studies have shown that erosive lesions are seen in prismatic enamel as characteristic demineralization patterns where either the prism cores or interprismatic areas dissolve, leading to a honeycomb structure. In aprismatic enamel the pattern of dissolution is more irregular and areas with various degrees of mineral loss are seen side by side. In dentin the first area to be affected is the peritubular dentin. With progressing lesions, the dentinal tubules become enlarged but finally disruption is seen also in the intertubular areas. If the erosion process is rapid, increased sensitivity of the teeth is the presenting symptom. However, in cases with slower progression, the patient may remain without symptoms even though the whole dentition may become severely damaged. Regarding the role of causative agents, present data does not allow the ranking of different acids with regard to their potential of causing erosion. Neither is there consensus as to how effective fluorides are in preventing the progression of erosive lesions, or how the chemical and structural factors of tooth tissue in general might modify this pathological process.

Acids↗
PubMed1996

Surface ultrastructure of rat molar teeth after experimentally induced erosion and attrition.

Young Osborne-Mendel rats were given different diets for 6 weeks. Effects of soft and rough food as well as acidic sport drink on the lingual surfaces of first mandibular molars were studied. In addition, the effect of fluoride on erosion was examined. A Jeol JSM-35 scanning electron microscope was used to visualize tooth surface ultrastructure. Intact surfaces were found in the rats given soft food and distilled water. Sport drink (pH 3.2) caused severe erosion with total loss of supragingival enamel and exposure of dentin. Attrition effects were seen on the cuspal parts of the surface when rough food was given. Tooth tissue loss was greatest in the rats given rough food and sport drink; signs of both erosion and attrition could be seen. When fluoride was added to the sport drink erosion lesions were less severe and if dentin was exposed, the dentinal tubules were partly occluded. These SEM observations support earlier studies which have suggested that erosion may alter tooth surface so that it is more susceptible to attrition; in those lesions, however, clinical diagnosis of the initial causes may be difficult.

Animals↗
PubMed1995

Respiratory tract infections and concomitant pericoronitis of the wisdom teeth.

OBJECTIVE: To discover if there is an association between respiratory tract infections and pericoronitis of erupting third molars in young adults. DESIGN: Data from male military conscripts' medical records were collected over five years and the incidence of respiratory tract infection before and after acute pericoronitis (191 cases) and before and after standard (722 cases) and operative (741) extractions compared with that in controls (n = 703) who had no infections in the third molar regions. SUBJECTS: 14,500 male military conscripts aged 20. SETTING: Garrisons in Valkeala and Kouvola, Finland. RESULTS: The incidence of respiratory tract infection was significantly higher during the two weeks before acute pericoronitis was diagnosed compared with that in controls. The highest incidence was observed in the three days before pericoronitis (odds ratio 6.8; 95% confidence interval 3.0 to 15.0). The incidence was also increased in the first week after pericoronitis (odds ratio 3.7; 1.6 to 8.4) and three days before (odds ratio 2.6; 0.9 to 7.5) and during the first week after extraction of third molars (odds ratio 2.6; 1.3 to 5.3). CONCLUSIONS: Respiratory tract infection may precipitate and occur concomitantly with acute pericoronitis. Third molar surgery for pericoronitis, on the other hand, may trigger respiratory tract infection.

Acute Disease↗
PubMed1995

Development of a rapid PCR method for identification of Helicobacter pylori in dental plaque and gastric biopsy specimens.

A rapid and simple polymerase chain reaction (PCR) method was developed to detect Helicobacter pylori in gastric biopsy specimens and dental plaque samples. The primers were targeted to the 16S rRNA sequence of Helicobacter pylori strain ATCC 43504. The system was found to have a theoretical detection level of 0.5 to 5 Helicobacter pylori cells in a 5 microliters sample of dental plaque. In the absence of plaque, the detection level was even better: theoretically, 0.05 to 0.5 Helicobacter pylori cells were detected in water suspension. However, this appeared to be due to the presence of free bacterial DNA in the culture used for the sensitivity determination. Thus, the actual sensitivity of the system was found to be fewer than five Helicobacter pylori cells, irrespective of the type of sample used. The method was then used to analyse 29 dental plaque and gastric biopsy specimens collected from patients with a history of recurrent peptic ulcer disease. Fourteen stomach specimens were positive for Helicobacter pylori when tested with the PCR method, while the respective figures with culture, histological examination and the urease test were 11, 12 and 9. No positive dental plaque samples were observed.

Adult↗