Biomedical subjects

C Lindqvist

Publications and source records attributed to C Lindqvist.

At least 19 recordsLinked to original sources

PubMed2001

Development of a time-resolved fluorescence resonance energy transfer assay (cell TR-FRET) for protein detection on intact cells.

An assay named Cell TR-FRET based on time-resolved fluorescence resonance energy transfer, here utilized for detection of receptor proteins on intact cells, is described. In this assay, intact membrane-biotinylated Sf9 cells expressing human interleukin-2Ralpha due to infection with a recombinant baculovirus were prelabeled with a streptavidin-europium (Eu(3+)) chelate, the donor. These prelabeled cells were used in a homogeneous assay by addition of a fluorochrome-labeled anti-hIL-2Ralpha-specific antibody, 7G7B6-Cy5, the acceptor. Binding of 7G7B6-Cy5 to hIL-2Ralpha expressed on the cell surface and europium-labeled streptavidin to surface biotin esters brings the donor and the acceptor in close proximity, allowing transfer of energy from the excited state donor to the acceptor. This energy transfer was specifically inhibited by unlabeled antibody and by free biotin. The described assay constitutes a general method since no specific component of the cell membrane is labeled, thereby allowing a number of binding studies on the cell membrane, including receptor density determinations, to be performed. In addition, due to the rapid fashion in which the Cell TR-FRET assay is accomplished, it can be a valuable method not only for identifying novel membrane-associated proteins, but also for drug screening of large samples in high-throughput format.

Animals↗

PubMed2001

Poor dental status increases acetaldehyde production from ethanol in saliva: a possible link to increased oral cancer risk among heavy drinkers.

Epidemiological data support evidence that poor dental status increases oral cavity cancer risk especially among heavy alcohol consumers, but the causality of this finding is unclear. The enzymatic conversion of ethanol by the physiological oral microflora may lead to an accumulation of the highly carcinogenic intermediate acetaldehyde. This study was conducted to evaluate the role of dental status on the microbial production of acetaldehyde from ethanol in saliva. The microbial acetaldehyde production from ethanol was related to the dental score in 132 volunteers. After adjustment for smoking, alcohol consumption, age and gender, poor dental status was shown to lead to an approximately twofold increase in salivary acetaldehyde production from ethanol (P=0.02). Our results could be an important factor underlying the role of poor dental hygiene and status in oral cancer risk associated with ethanol drinking.

Acetaldehyde↗

PubMed2001

Production and partial characterization of mouse monoclonal antibodies recognizing common cytokine receptor gamma chain (gammac) of human, mouse and primate origin.

Monoclonal antibodies specific for the common cytokine receptor gamma chain, gammac, were produced using traditional hybridoma technology. Fusion of P3X63-Ag8.653 myeloma cells with splenocytes from Balb/c mice immunized with Spodoptera frugiperda insect cells infected with the recombinant baculovirus VL1392-hIL-2Rgamma resulted in several hybridoma cell clones producing monoclonal gammac-specific antibodies. Four of these antibody-producing clones, IIIC3, IIIE8, IG3 and IF10C5, were further characterized by immunoblotting, flow cytometry and ELISA. Data are presented demonstrating that the generated monoclonal antibodies can identify the extracellular domain of the common cytokine receptor gamma chain of human and mouse origin, and two of the antibodies recognize gammac of primate origin as well.

Animals↗

PubMed2001

Generation of hydroxyl radicals by the antiviral compound phosphonoformic acid (foscarnet).

Phosphonoformic acid (foscarnet) is an antiviral agent that is used to treat severe cytomegalovirus infections in AIDS patients. We demonstrate by using the ferrous iron indicator Ferrozine and ascorbic acid (vitamin C) that foscarnet can chelate ferric iron and form a redox-active iron complex. By using the hydroxyl radical indicator coumarin-3-carboxylic acid we found that the foscarnet-Fe3 complex formed can readily catalyze hydroxyl radical (.OH) generation by the Fenton reaction: (Fe2+ + H2O2-4Fe3+ + .OH + -OH) if hydrogen peroxide and ascorbic acid are present. Hydroxylation of coumarin-3-carboxylic acid could be blocked by addition of known hydroxyl radical scavengers such as mannitol, sucrose, glucose and dimethyl sulfoxide. Moreover, by using a DNA nicking assay, we found that foscarnet catalyzed hydroxyl radicals can induce single strand brakes in DNA. The potency of the hydroxyl radicals formed to induce damage could also be demonstrated in a phosphate-free buffer where the hydroxyl radicals formed attacked and liberated phosphate from the foscarnet molecule. Our results indicate that foscarnet catalyzed hydroxyl radical formation might take place during conditions where a peroxide generating system(s), vitamin C and transitions metals are present.

Antiviral Agents↗

PubMed2001

Condylar process fractures in children: a follow-up study of fractures with total dislocation of the condyle from the glenoid fossa.

PURPOSE: The purpose of this study was to investigate the long-term clinical and radiologic outcome of nonsurgically treated, dislocated condylar fractures sustained during childhood. PATIENTS AND METHODS: Dislocated condylar process fractures were diagnosed in 34 children aged 15 years or younger from 1980 to 1991. Of these, 26 had been treated nonsurgically and were asked to participate in a follow-up examination. Eighteen patients, representing 69% of the total sample, took part in the study. All patients underwent a clinical investigation with special emphasis on temporomandibular joint (TMJ) function. The patients also underwent a radiologic investigation, focusing on fracture remodeling and symmetry of the mandible. RESULTS: After a follow-up period ranging from 4.8 to 16.4 years (mean, 8.6 years), 56% had some subjective symptoms, and 72% had some objective signs of TMJ dysfunction. In general, however, the symptoms and signs of dysfunction were very slight. No correlation was observed between the method of nonsurgical treatment and the clinical results. Radiologic investigation showed incomplete remodeling (76.5%) and asymmetry of the mandible (64.7%) in most patients. The asymmetry was slight, however, and could not be observed clinically. CONCLUSIONS: Conservative treatment of dislocated condylar process fractures in children results in satisfactory long-term outcome of jaw function despite a high frequency of radiologically noted aberrations. Soft diet with immediate mobilization seems to be the treatment of choice.

Adolescent↗

PubMed2001

Differences between patients with or without the need for intensive care due to severe odontogenic infections.

PURPOSE: Despite greatly improved dental health in industrialized countries, severe odontogenic infections still occasionally lead to hospitalization. The aim of the present study was to determine whether what symptoms, signs, or laboratory parameters on hospital admission were associated with the need for treatment in the intensive care unit (ICU). PATIENTS AND METHODS: Over an 18-month period, 100 consecutive patients (59 male, 41 female) were included in the study. Twenty percent of the patients required ICU treatment because of cardiorespiratory problems or severe complications of their infection. Both ICU and non-ICU patients were examined clinically and blood samples were taken and studied in respect to several parameters associated with infection, including C-reactive protein (CRP) levels. The findings were analyzed statistically for differences between the groups. RESULTS: No particular anamnestic background variable was associated with the need for intensive care. However, a particularly high CRP level on admission was found to be associated with a more severe course of the infection. CONCLUSIONS: This study showed that determination of CRP levels may be useful in clinical decision-making in patients with severe odontogenic infections.

Adult↗

PubMed2001

A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study.

Four mandibular screw-plate locking systems were studied in sheep. Three to four centimetres angular continuity resections of the mandible were performed and the defects bridged with pre-bent angular reconstruction plates fixed with four screws in the body part and three in the ramus. Each type was used four times. Clinical and radiological examinations were carried out 1 and 2 months later. All sheep were able to eat and ruminate normally throughout the postoperative period. Radiology revealed that 6/16 plates and 5/112 screws fractured during the follow-up period. In one type, no fracture occurred. Screw fracture was confined to just one reconstruction system. Six of 16 mandibles showed slight to moderate bone resorption under the plate. The results point to the internal shortcomings of the systems tested.

Animals↗

PubMed2001

Disodium clodronate in the treatment of diffuse sclerosing osteomyelitis (DSO) of the mandible.

Diffuse sclerosing osteomyelitis (DSO) of the mandible is a chronic condition, the cause of which is not known. Jaw pain, occurring irregularly, is a typical symptom. The aim of the study was to assess the effectiveness of disodium clodronate for relieving pain in patients with DSO. Disodium clodronate is a bisphosphonate used to treat diseases of bone and calcium metabolism. Ten DSO patients experiencing pain received disodium clodronate or placebo intravenously on a randomized double-blind basis. Both minimum (300 mg) and maximum (900 mg) doses were well tolerated. Disodium clodronate administration did not result in better immediate pain relief than placebo administration. However, 6 months after treatment there was a statistically significant difference in pain intensity between the groups, with the disodium clodronate group experiencing significantly less pain.

Adult↗

PubMed2001

Effectiveness of operative treatment of internal orbital wall fracture with polydioxanone implant.

Many implants, some made from teflon or silicone, have been used for internal orbital wall reconstruction. Late complications relating to use of such implants have been reported. In this prospective study a polydioxanone (PDS) implant absorbable in vivo was used for internal orbital wall reconstruction. Follow-up involved clinical examination, magnetic resonance imaging (MRI) and computerized tomography (CT). Clinical examinations were undertaken before operation and up to 36 weeks postoperatively. Sixteen consecutive patients (10 pure blow-out fractures, six with associated zygomatic fracture) took part in the study. Prevalences of diplopia, proptosis and enophthalmus were recorded during each follow-up examination. This study revealed no muscle entrapment within the fracture line. Although CT results confirmed bone growth in the internal orbital wall, shape was unsatisfactory, and orbital volume was not reduced. MRI revealed thick scar formations in six cases (37.5%), fibrotic sinuses filled with air or gas in three cases (19%) and a fibrotic sinus with fluid around the PDS in one case (6%). Our results suggest that use of PDS in reconstructing the internal orbital wall is inadvisable.

Absorbable Implants↗

PubMed2001

Oral symptoms at menopause--the role of hormone replacement therapy.

OBJECTIVE: A questionnaire was used to investigate the prevalence of self-assessed sensations of painful mouth (PM) and dry mouth (DM) in menopause-aged women. Special attention was paid to the association of the use of hormone replacement therapy (HRT) with oral symptoms. Our hypothesis was that women using HRT have fewer oral symptoms than those who do not use HRT. STUDY DESIGN: Patients were selected from among 50- to 58-year-old women attending a communal mammography screening program in Helsinki, Finland. Every fifth woman was offered a structured questionnaire. RESULTS: Completed questionnaires were received from 3173 women (response rate, 65%). Of the total sample, 46.8% (n = 1486) used HRT. The occurrence of PM was 8.2% (n = 259) and DM, 19.9% (n = 631). Climacteric symptoms were reported by 24% (n = 761) of the total sample and by 19.2% (n = 285) of the HRT users. According to logistic regression analyses, climacteric symptoms were found to be predictive of PM (P =.000) and DM (P =.000). The use of HRT also increased the occurrence of PM (P =.03). However, as a single covariate in our statistical model, the use of HRT was not a predictor of PM. The use of HRT also did not correlate with the occurrence of DM. CONCLUSIONS: The occurrence of PM and of DM seemed to be associated with climacteric symptoms in general, and the use of HRT did not prevent the oral symptoms studied.

Age Factors↗

PubMed2001

Focal sialadenitis in patients with ankylosing spondylitis and spondyloarthropathy: a comparison with patients with rheumatoid arthritis or mixed connective tissue disease.

OBJECTIVES: To investigate the occurrence of and risk factors for focal sialadenitis in patients with rheumatoid arthritis (RA), mixed connective tissue disease (MCTD), ankylosing spondylitis (AS), and spondyloarthropathy (SpA). METHODS: A total of 85 patients (25 with RA, 19 with MCTD, 19 with AS, 22 with SpA) participated in the study. Each patient filled out a questionnaire for eye and oral symptoms and for the use of medication, and was interviewed; other tests included Schirmer's test, laboratory tests, collection of unstimulated and stimulated whole saliva, and minor salivary gland biopsy. A focus score of > or =1 was regarded as an indicator of focal sialadenitis. RESULTS: Focal sialadenitis was observed in 68% (57/84) of all patients. It affected 80% (20/25) of the patients with RA, 94% (17/18) of those with MCTD, 58% (11/19) of those with AS, and 41% (9/22) of those with SpA (chi(2) test, p=0.0013). Salivary secretion correlated negatively with the focus scores-that is, severity of focal sialadenitis. Patients with focal sialadenitis had both decreased salivary secretion and decreased tear secretion significantly more often than did patients without (chi(2) test, p=0.0074 and p=0.048 respectively). Patients with positive rheumatoid factor (RF), antinuclear antibodies (ANA), or SSA or SSB antibodies had sialadenitis significantly more often than did patients with negative antibodies. In the subgroup of patients with AS or SpA, no associations were found between focal sialadenitis and the presence of these antibodies. CONCLUSION: In addition to patients with RA or MCTD, focal sialadenitis also affects a very high proportion of patients with AS or SpA. Focus scores are significantly higher in patients with RA or MCTD than in those with AS or SpA. A significant association exists between focal sialadenitis and RF, ANA, SSA and SSB. However, in the subgroup of patients with AS or SpA, no associations were found between focal sialadenitis and serological markers or clinical symptoms.

Adult↗

PubMed2000

Oral health of patients scheduled for elective abdominal aortic correction with prosthesis.

OBJECTIVE: to evaluate the frequency of potential oral foci of infection in patients scheduled for elective abdominal aortic surgery. DESIGN: prospective clinical study. MATERIALS: oral health and dentures of 50 patients (33 males and 17 females, mean age 65 years) were examined before aortic surgery. CHIEF OUTCOME MEASURES: radiographic and clinical examination with special emphasis on identifying acute and chronic oral and ontogenic conditions which may contribute to aortic prosthesis infection. RESULTS: eighty-two per cent of the patients had some oral infection foci. The mean number of remaining teeth in the cohort was 9.3, and 21% of these were potential infectious foci (62% in the patients). Twenty-six per cent of the patients suffered from oral Candida infection. Seventy-four per cent of the patients had total or partial dentures, 45% of which were ill-fitting and needed repair. CONCLUSIONS: oral infectious foci occur frequently in patients needing aortic surgery. Untreated foci may contribute to aortic prosthesis infection. Preoperative oral evaluation and elimination of intraoral infection is recommended for patients scheduled for abdominal aortic repair.

Acute Disease↗

PubMed2000

Increased salivary acetaldehyde levels in heavy drinkers and smokers: a microbiological approach to oral cavity cancer.

The pathogenetic mechanisms behind alcohol-associated carcinogenesis in the upper digestive tract remain unclear, as alcohol is not carcinogenic. However, there is increasing evidence that a major part of the tumour-promoting action of alcohol might be mediated via its first, toxic and carcinogenic metabolite acetaldehyde. Acetaldehyde is produced from ethanol in the epithelia by mucosal alcohol dehydrogenases, but much higher levels derive from microbial oxidation of ethanol by the oral microflora. In this study we investigated factors that might alter the composition and quantities of the oral microflora and, consequently, influence microbial acetaldehyde production. Information about dental health, smoking habits, alcohol consumption and other factors was obtained by a questionnaire from 326 volunteers with varying social backgrounds and health status, e.g. oral cavity malignancy. Paraffin-induced saliva was collected and the microbial production of acetaldehyde from ethanol was measured. Smoking and heavy drinking were the strongest factors increasing microbial acetaldehyde production. Whether poor dental status may alter local acetaldehyde production from ethanol remained unanswered. Bacterial analysis revealed that mainly gram-positive aerobic bacteria and yeasts were associated with higher acetaldehyde production. Increased local microbial salivary acetaldehyde production due to ethanol among smokers and heavy drinkers could be a biological explanation for the observed synergistic carcinogenic action of alcohol and smoking on upper gastrointestinal tract cancer. It offers a new microbiological approach to ethanol-associated carcinogenesis at these anatomic sites.

Acetaldehyde↗

PubMed2000

Collagenases in different categories of peri-implant vertical bone loss.

The loosening of dental implants is associated with peri-implant vertical bone loss. The mechanisms and mediators of this bone destruction are not known. To test the hypothesis that collagenase-2 and collagenase-3 might be markers or maybe even mediators in this process, we measured collagenase-2 (time-resolved immunofluorometric assay) and collagenase-3 (quantitative immunoblot) in peri-implant sulcus fluid in 49 implant sites in 13 patients. Vertical bone loss was graded as being < 1 mm, from 1 to 3 mm, or > 3 mm. The severity of inflammation, as rated according to Gingival Index, did not correlate with the category of bone loss (p > 0.05). Collagenase-2 and collagenase-3 were higher (p < 0.05) in the group which had lost > 3 mm of bone than in the two other groups. Gingival Index is not a clinically important marker for bone loss, but collagenase-2 and collagenase-3 in peri-implant sulcus fluid are. They might participate in peri-implant osteolysis.

Adult↗

PubMed2000

Bioabsorbable plates and screws: Current state of the art in facial fracture repair.

BACKGROUND AND OBJECTIVES: The use of bioabsorbable materials in craniomaxillofacial surgery began a new era in fracture fixation. The purpose of this paper is to review the historical perspectives and the current concept of bioresorbable materials in fracture fixation. METHODS AND MATERIALS: The authors review the biochemistry and clinical characteristics of bioabsorbable polymers--polylactic acid (PLA), polyglycolic acid (PGA), polydioxanone (PDS), and their copolymers. Their use and clinical perspectives by the Helsinki (authors') group and other study groups are presented. RESULTS AND CONCLUSIONS: These materials have proven to be safe in clinical applications. When manufactured with current technology, they are easy to handle. Economically, they are nearly equal to similar metal devices. The materials have met clinical success throughout the world, first in orthognathic surgery, followed by treatment of fractures of the upper facial skeleton and the mandible. Today, most maxillofacial fractures and osteotomies may be adequately fixed with bioabsorbable materials.

Absorbable Implants↗

PubMed2000

[The unknown SAPHO].

Explore the source record for details and available documents.

Acquired Hyperostosis Syndrome↗

PubMed1999

Detection of baculovirus-infected insect cells by flow cytometric side-scatter analyses.

BACKGROUND: The baculovirus expression vector system (BEVS), utilizing the Autographa californica nuclear polyhedrosis virus (AcNPV), has turned out to be an attractive alternative for high-level expression (<600 mg/l) of recombinant proteins. However, there is a shortage of reliable methods for monitoring the infection process in situations where marker proteins cannot be used. METHODS: Three recombinant baculoviruses, FastBac1-wtGFP, VTBac-GFP, and VL1392-hIL-2Ralpha, all having the genes inserted under the transcriptional control of the polyhedrin gene promoter of the Autographa californica nuclear polyhedrosis virus (AcNPV), were used to infect Spodoptera frugiperda (Sf9) and Mamestra brassicae (IZD-MB-0503) insect cells. The infection process of the recombinant baculoviruses was monitored by flow cytometric side-scatter and fluorescence intensity analyses over a period of 6-96 h. RESULTS: A clear correlation between the side-scatter (SSC) signal and the relative fluorescence was observed for both of the infected cell lines, compared to noninfected cells. Comparison of SSC histograms from noninfected insect cells with cells infected with the nonfluorescent recombinant baculovirus VL1392-hIL-2Ralpha showed a clear increase of SSC for the infected cells. CONCLUSIONS: The SSC parameter can therefore be utilized for flow cytometric monitoring of a baculovirus infection process in situations where suitable markers are not available.

Animals↗

PubMed1999

Generation of a new protein purification matrix by loading ceramic hydroxyapatite with metal ions--demonstration with poly-histidine tagged green fluorescent protein.

The gene encoding the green fluorescent protein (GFP) from the jellyfish Aequorea victoria, was inserted under transcriptional control of the polyhedrin promoter of the Autographa californica nuclear polyhedrosis virus and expressed in the Spodoptera frugiperda insect cell line Sf9 during viral infection. The baculovirus transfervector pBlueBacHisB was used for constructing the recombinant baculovirus, so that the green fluorescent protein could be tagged with a poly-histidine tail. This fusion protein was utilized as a marker for evaluating the properties of metal ion loaded ceramic hydroxyapatite as a matrix in protein purification. Ceramic hydroxyapatite loaded with Zn(II) was the best choice for purifying this poly-histidine tagged GFP, followed by Fe(III) of the metal ions tested. Ni(II) that is superior especially in many poly-histidine purification systems did not, when loaded to hydroxyapatite, have binding properties comparable to Zn(II) or Fe(III). Elution of poly-histidine tagged GFP was best performed with phosphate buffers or EDTA that could compete with the phosphate molecules in hydroxyapatite or complexly bind the metal ions, respectively.

Animals↗