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Biomedical subjects

L E Linder

Publications and source records attributed to L E Linder.

At least 19 recordsLinked to original sources
PubMed2001

[Infection a dreaded central venous catheter-related complication. A reminder of the significance of good aseptics is justified].

The use of central venous catheters has increased markedly. Large numbers of patients are therefore at risk for catheter-related infections. This paper reviews the literature on prevention of intravascular catheter-related complications. Microbes colonising the catheter hubs and the skin around the insertion site are the source of most of these infections. By simple routines it is possible to reduce the risk for microbial spread from these sites to the bloodstream.

Anti-Bacterial Agents↗
PubMed2001

Smoking and subgingival microflora in periodontal disease.

AIM: The present investigation was undertaken to analyze the influence of smoking on the periodontal disease associated subgingival microflora. The population included 33 smokers and 31 non-smokers in the age range 36-86 years. METHODS: Microbial samples were obtained from 4 sites per patient. The checker-board DNA-DNA hybridization technology was used for detection of the bacterial species P. gingivalis, P. intermedia, P. nigrescens, B. forsythus, A. actinomycetemcomitans, F. nucleatum, T. denticola, P. micros, C. rectus, E. corrodens, S. noxia and S. intermedius. RESULTS: Using score 1 as cutoff, contrasting colonized versus non-colonized patients, 8 out of 12 species were detected in > or = 90% of both smokers and non-smokers. Using score 4 as cutoff, contrasting heavily colonized patients versus non-colonized and less heavily colonized patients, the detection rates decreased in both smokers and non-smokers. No significant differences in detection rates were observed between smokers and non-smokers. Logistic regression analysis indicated that neither smoking, probing depth nor gingival bleeding influenced the occurrence of the species analyzed. The lack of a smoking exposure dose-response further supported the indication of a limited influence of smoking. CONCLUSION: Smoking exerts little, if any, influence on the subgingival occurrence of several of the bacteria most commonly associated with periodontal disease.

Adult↗
PubMed2001

Effect of fluoride on glucose incorporation and metabolism in biofilm cells of Streptococcus mutans.

The aim of this study was two-fold: firstly, to study the effect of high fluoride concentrations on carbohydrate metabolism in Streptococcus mutans present in biofilms on hydroxyapatite; and, secondly, to evaluate the effect of fluoride-bound hydroxyapatite on lactic acid formation in growing biofilms of Strep. mutans. Biofilms of a clinical strain of Strep. mutans on saliva-coated hydroxyapatite beads were incubated with sodium fluoride over a wide range of concentrations. At high fluoride concentrations (>10 mM) the incorporation of [14C]-labeled glucose decreased by 80-85%, at both pH 7.0 and 5.6. At lower fluoride concentrations, the effect of fluoride on the incorporation of labeled glucose was pH-dependent in both biofilm cells and in planktonic cells. At pH 7.0, fluoride at concentrations < 10 mM had little or no effect. Pretreatment of hydroxyapatite discs with fluoride varnish (Fluor Protector) or fluoride solutions caused a statistically significant reduction of lactic acid formation in associated, growing biofilms of Strep. mutans. Fluoride varnish and 0.2% (47.6 mM) sodium fluoride solution exhibited a statistically significant inhibitory effect on lactate production.

Biofilms↗
PubMed2000

Smoking and GCF levels of IL-1beta and IL-1ra in periodontal disease.

AIMS: GCF levels of the cytokine IL-1beta and its receptor antagonist IL-1ra were analyzed with respect to smoking in patients with moderate to severe periodontal disease. The study population included 22 smokers and 18 non-smokers in the age range 32-86 years. Concomitantly, the GCF levels of IgA, IgG, albumin and total protein were analyzed. METHOD: Samples of GCF were obtained from 2 diseased sites in each patient by means of an aspiration method. IL-1beta, IL-1ra, IgA and IgG were determined with immunoelectrophoresis. Total protein was determined by the BCA method. RESULTS: The clinical characteristics in terms of probing depth and frequency of diseased sites and supragingival plaque did not differ between smokers and non-smokers. Gingival bleeding, however, was significantly depressed in smokers. IL-1beta was detected in GCF of 95% of both smokers and non-smokers and IL-1ra in all patients. The GCF level of IL-1ra was approximately 1,000-fold that of IL-1beta. The GCF levels of IL-1beta and IL-1ra were high in comparison with those of TNF-alpha and IL-6 determined by the same method in our earlier studies. CONCLUSION: Our observations did not reveal any influence of smoking on the levels of IL-1beta and IL-1ra in GCF.

Adult↗
PubMed2000

Tumor necrosis factor-alpha and transforming growth factor-beta1 in chronic periapical lesions.

OBJECTIVE: Proinflammatory cytokines are involved in the pathogenesis of periapical lesions. The purpose of this study was to evaluate the presence of the cytokines tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta(1) (TGF-beta(1)) in periapical pathosis and to determine their relationship to the size of the lesions. STUDY DESIGN: One tooth from each of 25 patients was root-end resected, and the periapical lesion was collected. The amounts of TNF-alpha and TGF-beta(1) were assessed by enzyme-linked immunosorbent assay. RESULTS: TGF-beta(1) was detected in 21 of 25 lesions. In samples with scar tissue, no TGF-beta(1) activity was detected. A statistically significant correlation was found between TGF-beta(1) per milligram of tissue and the diameter of the lesions. TNF-alpha was detected in only 2 samples. CONCLUSIONS: TGF-beta(1) was present in periapical granulomas and cysts but not in lesions with scar tissue. The correlation between the amount of TGF-beta(1) per milligram of tissue and the size of the lesion was significant.

Adult↗
PubMed1999

Outcomes of periradicular surgery in cases with apical pathosis and untreated canals.

OBJECTIVE: Surgical management is intended to eliminate or block infection originating in the root canals. The root end is customarily sealed to prevent pathogenic products remaining in the root canal from reaching the periradicular tissues. The purpose of this study was to evaluate the microbiologic and radiographic outcomes of surgical treatment of periradicular pathosis associated with teeth with necrotic pulps. STUDY DESIGN: One tooth from each of 10 patients was root-end resected and root-end filled without prior root canal treatment. One year postoperatively, the outcomes were assessed radiographically and the root canals were sampled for bacteria. RESULTS: Radiographic examination showed complete or incomplete (scar tissue) healing in 5 teeth and uncertain healing in the other 5 teeth. Bacteriologic samples from the root canals were positive in 9 of the 10 cases. CONCLUSIONS: In teeth with necrotic pulps, treatment of periradicular pathosis by surgery and root-end filling may show radiographic evidence of satisfactory healing 1 year postoperatively. However, viable bacteria may persist in the canals, constituting a potential risk factor for recurrence of periradicular pathosis.

Adult↗
PubMed1999

Smoking and crevicular fluid levels of IL-6 and TNF-alpha in periodontal disease.

Smoking is a well-documented risk factor for periodontal disease, although the mechanisms of its negative influence are not well understood. In the present study, the influence of smoking on the gingival crevicular fluid (GCF) content of the pro-inflammatory cytokines IL-6 and TNF-alpha was investigated in patients with moderate to severe forms of the disease. The study base consisted of 108 patients including 45 current smokers, 28 former smokers and 35 non-smokers. The median GCF sample levels of IL-6 and TNF-alpha were 5.0 pg/ml and 61.0 pg/ml, respectively, for current smokers, 13.0 pg/ml and 51.0 pg/ml, respectively, for former smokers, and 10.0 pg/ml and 12.0 pg/ml, respectively, for non-smokers. The differences between smoking groups with regard to IL-6 were not significant suggesting that the IL-6 content was not influenced by smoking. In contrast, the TNF-alpha content was significantly increased in current smokers as compared to non-smokers confirming our previous observations. The present results in patients with moderate to severe periodontal disease may indicate different mediator functions of IL-6 and TNF-alpha in response to smoking.

Adult↗
PubMed1998

Clinical expression of TNF-alpha in smoking-associated periodontal disease.

The level of TNF-alpha in gingival crevicular fluid (GCF) was analyzed with respect to smoking in patients with untreated moderate to severe periodontal disease including 30 current smokers, 19 former smokers and 29 non-smokers, in the age range 31-79 years. Concomitantly the occurrence of the periopathogens Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) and the GCF levels of albumin, IgA and IgG were analyzed. With regard to clinical characteristics, there were no statistically significant differences between smoking groups. The occurrence of patients positive for the periopathogens Aa, Pg and Pi was 28.2%, 41.0% and 91.0%, respectively. There were no statistically significant differences between smoking groups with regard to occurrence or relative frequency of these periopathogens. An exception was a significantly lower occurrence of Aa in former smokers as compared to non-smokers. The chief novelty of the study was the observation of a clearly increased level of TNF-alpha in GCF associated with smoking. Both current and former smokers exhibited significantly higher levels of TNF-alpha in comparison to non-smokers, whereas the levels of albumin, IgA and IgG were the same irrespective of smoking. In conclusion, the present observations in patients with moderate to severe periodontal disease suggest that smoking is associated with elevated GCF levels of the cytokine TNF-alpha.

Adult↗
PubMed1998

Influence of smoking on the outcome of periodontal surgery. A 5-year follow-up.

The 5-year outcome following periodontal surgery was evaluated in 57 patients that had received regular maintenance care throughout the follow-up period. The study population included 20 smokers, 20 former smokers and 17 non-smokers in the age range 37-77 years. The clinical characteristics evaluated were supragingival plaque, gingival bleeding and pocket probing depth. The region assigned for surgery was, in addition, radiographically evaluated in terms of periodontal bone height. Furthermore, the occurrence of the periopathogens Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) and the gingival crevicular fluid (GCF) levels of tumor necrosis factor alpha (TNF-alpha) were assessed at follow-up. Plaque index was 28.5% at baseline and 32.9% at follow-up, indicating a good standard of oral hygiene, and gingival bleeding 31.7% and 24.9%, respectively, suggesting a low to moderate level of gingival inflammation. In regions assigned for surgery, pocket probing depth decreased significantly from on average 5.6 mm to 4.3 mm (p<0.0001) and periodontal bone height increased significantly from on average 62.5% to 67.5% (p<0.0001). In terms of bone height, the outcome was less favorable among smokers compared with non-smokers. There was a predominance of smokers among patients exhibiting loss of bone height after the 5 years of maintenance. No significant associations were found between the therapeutical outcome and supragingival plaque or subgingival occurrence of periopathogens. The associations between GCF levels of TNF-alpha and probing depth and bone height were unclear, whereas the level of TNF-alpha was significantly elevated in smokers.

Adult↗
PubMed1998

Cellular heterogeneity in non-immune IgG-binding in a strain of Streptococcus mitis.

Electron microscopy revealed that Streptococcus mitis ATCC 903 bound gold probes conjugated with goat IgG by non-immune mechanisms. Only a few of the cells and the cell wall fragments could bind IgG, in contrast to Staphylococcus aureus and Streptococcus group G which showed a more homogeneous binding to nearly all cells or cell wall fragments.

Cell Wall↗
PubMed1996

Analysis of sodium dodecyl sulfate-stable cell wall aminopeptidases in strains of viridans streptococci.

Cell wall extracts from nine strains of viridans streptococci representing five species were analyzed for aminopeptidases. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis in combination with zymogram procedures revealed a common pattern of aminopeptidases in six strains, all having enzyme bands at 89 and 45 kDa. Three strains had an additional band at 200 kDa. Crossreactivity between aminopeptidases of all active strains was shown with crossed immunoelectrophoresis. Strains of Streptococcus mutans and S. sobrinus were without detectable cell wall aminopeptidases.

Aminopeptidases↗
PubMed1996

Clinical management of nonhealing periradicular pathosis. Surgery versus endodontic retreatment.

OBJECTIVES: This prospective randomized study compared the outcome of retreatment and surgical intervention in root canal treated teeth with nonhealing periradicular pathosis. STUDY DESIGN: One such tooth from each of 38 patients was randomly allotted to retreatment or root-end resection and root-end filling. Treatment outcome after 1 year was evaluated and compared clinically and radiographically. RESULTS: The success rate for surgery was higher than for conventional retreatment, but the difference was not statistically significant. CONCLUSIONS: For management of nonhealing periradicular pathosis associated with root canal treated teeth, surgical intervention should be considered as an alternative to retreatment. In cases with a similar prognosis for both modes of treatment, the choice should be governed by consideration of intrinsic and extrinsic factors.

Adult↗
PubMed1993

Subcutaneous sterile water injections for chronic neck and shoulder pain following whiplash injuries.

In many cases of whiplash injury symptoms persist and do not respond to treatment. There is uncontrolled evidence to suggest that intracutaneous injections of sterile water might help. Since that route may be unacceptable to patients the subcutaneous route is used in the randomised trial reported here. 40 patients with whiplash syndrome, mean age 46 years (24-73) were given subcutaneous injections of 0.3-0.5 ml sterile water or saline over tender and trigger points in the neck and shoulder. A maximum of three treatments were given during the first two months of the study and the patients were followed up for 8 months. The accidents had occurred 4-6 years previously. X-ray examinations revealed no traumatic spinal lesions. Neck mobility and pain levels were evaluated by a physiotherapist immediately before and after the first treatment and after 1, 3, and 8 months. After 3 months, the mean total mobility of the cervical spine had increased by 39 degrees in the sterile water group and 6 degrees in the saline group (p < 0.05). Minimum and maximum levels of pain in the weeks just before treatment were evaluated by a visual analogue scale from 0 to 10. After 3 months the minimum pain level had fallen from 2.2 to 1.4 in the sterile water group but was not reduced in the saline group (p < 0.02); the maximum had fallen from 8.1 to 3.8 in the sterile water group and from 8.3 to 7.5 in the saline group (p < 0.001). After 3 months, 19 of 20 patients in the sterile water group assessed their condition as generally improved but only 6 in the saline group felt that they had got better. After 8 months there were still significant differences for minimum pain score and for mobility but not for maximum pain or for self-assessment of improvement.

Adult↗
PubMed1992

Purification and characterization of an aminopeptidase from Streptococcus mitis ATCC 903.

An aminopeptidase isolated from the cytoplasmic fraction of a cell extract of Streptococcus mitis ATCC 903 was purified 330-fold by ion-exchange chromatography, gel filtration, and hydroxyapatite chromatography. The partially purified enzyme had a broad substrate specificity. Twelve aminoacyl-beta-naphthylamide substrates were hydrolyzed and also several di-, tri-, tetra-, and pentapeptides and bradykinin. The enzyme hydrolyzed arginine-beta-naphthylamide at the highest rate. Optimal conditions for activity were at pH 7.0-7.2 and at 37-40 degrees C. The molecular weight of the enzyme was estimated to be 93,000. The enzyme was activated by Co2+ ions. Hg2+ inhibited the activity completely. SDS, EDTA, urea, and pCMB also inhibited activity. Inhibition by EDTA could be completely reversed by dialysis and addition of Co2+ ions. Reducing agents, sodium fluoride, and PMSF had no effect on the activity of the enzyme. The isoelectric point of the enzyme was at pH 4.3. High substrate concentrations inhibited activity. Substrate inhibition increased in the presence of high concentrations of Co2+ ions.

Amino Acid Sequence↗
PubMed1992

Neuropathologic findings after long-term intrathecal infusion of morphine and bupivacaine for pain treatment in cancer patients.

Epidural or intrathecal infusions of morphine and bupivacaine mixtures are presently used for the treatment of "refractory" cancer pain even though the neurotoxic potential of such mixtures is unknown. The pathologic findings of the spinal column, the meninges, the nerve roots, and the spinal cord, and the clinical neurologic deficits were recorded in 15 patients (5 men and 10 women), aged 26-83 (median 68) yr, treated for 4-274 (median 81) days with intrathecal infusions of morphine (with preservatives [sodium metabisulfite and sodium edetate]) and bupivacaine mixtures, given through open, subcutaneously tunneled nylon catheters. Six patients had been subjected to radiation therapy (20-96 Gy), applied over the spinal column, and four had been treated with antineoplastics believed to be neurotoxic. Ten patients had various neurologic deficits before the intrathecal treatment. The cumulative doses (ranges) given intrathecally were: morphine 33-11,900 mg, sodium metabisulfite 3.3-1,050 mg, sodium edetate 0.33-105 mg, and bupivacaine 10-41,400 mg; cumulative volumes were 16-9,400 ml. The concentrations of the drugs in the mixtures were: morphine 0.25-4.0 mg/ml, sodium metabisulfite 0.025-0.40 mg/ml, sodium edetate 0.0025-0.04 mg/ml, and bupivacaine 3.0-4.75 mg/ml. The osmolality of the mixtures in vitro ranged from 282 to 286 mOsm/kg and the pH from 4.1 to 4.6. The pathologic findings consisted of vertebral metastases (n = 6), epidural and/or intrathecal tumor masses (n = 8), focal subdural fibrosis (n = 6), infiltration of mononuclear cells in the subarachnoid space (n = 10), and discrete injuries (nerve fiber degeneration or fibrosis) to the anterior (five patients) and posterior (seven) nerve roots, and spinal cord (tumor compression [one], slight thickening of the leptomeninges [one], and thrombosis of a spinal artery and medullary infarction [one]). In none of the cases was any reaction against the nylon catheter within its subarachnoid course recorded. The neuropathologic findings were not related to the duration or cumulative doses of the intrathecal treatment. No new neurologic deficits that could be attributed to the intrathecal administration of the opiate-bupivacaine mixtures were recorded. The neuropathologic and clinical neurologic findings in cancer patients treated with intrathecal morphine-bupivacaine mixtures appeared similar to those in animals and humans reported with either intrathecal morphine or bupivacaine alone.

Adult↗
PubMed1992

Bacteriology, drug stability and exchange of percutaneous delivery systems and antibacterial filters in long-term intrathecal infusion of opioid drugs and bupivacaine in "refractory" pain.

OBJECTIVE: To provide a basis for recommendations on the exchange of containers (syringes and cassettes) and antibacterial filters, and for choice of administration device in patients with "refractory" pain treated with long-term percutaneous intrathecal (IT) infusions of opioid (morphine or buprenorphine) and bupivacaine mixtures. DESIGN: Prospective, cohort, nonrandomized control trial-case series, with consecutive sample, no standard criterion, and cost-benefit analysis. SETTING: Tertiary care center, institutional practice as well as hospitalized and ambulatory care. PATIENTS: Eighty-nine (51 women and 38 men); 81 with malignant pain and 8 with benign "refractory" pain. INTERVENTIONS: (a) The chemical stability of the drugs in the containers during 30 days. (b) The results of bacteriologic culture of the residual volumes of the analgesic mixtures from used and reused (1-16 times) syringes (n = 135) and cassettes (n = 258), and of 5 ml of sterile isotonic saline filtered through the used Millipore filters (n = 149). The bacteriologic samples from the 89 patients were taken after 1-40 (median = 7), 1-86 (median = 20), and 5-78 (median = 31) days of IT treatment, respectively. MAIN OUTCOME MEASURES: Chemical stability: buprenorphine and bupivacaine concentrations-liquid chromatography; morphine concentrations--gas chromatography. Bacteriologic cultures: standard laboratory procedures. The hypothesis (repeated use of the infusion systems and their exchange once a month does not significantly affect drug concentrations or increase the infection risk) was elaborated before data collection began. RESULTS: The bupivacaine-opioid mixtures were found to be chemically stable within 3-10% of the original doses up to 30 days. Seventeen cultures (from five syringes, six cassettes, and six filters) in 13 patients (having no signs of meningeal infection) were found to be colonized with Staphylococcus aureus (n = 4), coagulase negative staphylococci (n = 7), viridans streptococci (n = 3), Neisseria sp (n = 4), Corynebacterium sp (n = 4), Enterobacter sp (n = 2), Klebsiella sp (n = 3), gram-negative bacilli (n = 1), and yeasts (n = 2). The place of IT treatment, its duration, and patient-related infection risk factors (age; malignancy; diabetes; presence of a colostomy, pyelostomy, or indwelling urinary catheter; and the presence and location of infection foci) were not related to the results of the cultures. However, 9 of the 17 positive cultures came from patients with skin ulcers, a notable incidence. The positive cultures had no connection with the cultured item, its in-use duration, the number of times of reuse, the analgesic drugs used, their concentrations or the presence of preservatives (sodium metabisulfite and sodium edetate), or the antiseptic agent (70% ethanol or 0.5% chlorhexidine gluconate) used during bacteriologic sampling. The bacterial growth was sparse in 14 and massive in 3 of the 17 positive cultures. One item (filter) from one patient with meningitis was sterile. CONCLUSIONS: In our population, exchange of the infusion systems when they are empty (within 1 month) and of the antibacterial filters once a month does not appear to affect the concentrations of, or increase the infection risk from, the opioid-bupivacaine mixtures. The risk of bacterial contamination/colonization of the syringes from syringe drivers does not seem to be higher than that of cassettes from external portable pumps.

Adolescent↗
PubMed1992

Occurrence of periopathogens in smoker and non-smoker patients.

The aim of the present study was to elucidate the interrelationship between cigarette smoking and the occurrence of periopathogens, i.e., Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius. The study was based on 145 patients with clinically severe periodontitis, 52 men (age range 32-73 years) and 93 women (age range 32-74 years). 83 patients were smokers (> or = 15 cigarettes/day) and 62 non-smokers. Bacterial samples were collected from one site with a probing depth > or = 6 mm for each individual. There were no statistically significant differences in bacterial counts between smokers and non-smokers (p > 0.05). The relative frequencies of smokers and non-smokers positive for A. actinomycetemcomitans were 31% and 31%, for B. gingivalis 42% and 44%, and for B. intermedius 65% and 53%, respectively. The differences between smoking groups were not statistically significant (p > 0.05). The occurrence in different combinations of these bacteria was also determined. There were no statistically significant differences between smoking and combinations of periopathogens (p > 0.05). The results suggest that smoker and non-smoker patients do not differ with regard to occurrence, relative frequency or different combinations of A. actinomycetemcomitans, B. gingivalis and B. intermedius.

Adult↗