Biomedical subjects

C Lindqvist

Publications and source records attributed to C Lindqvist.

At least 127 records · Page 7Linked to original sources

PubMed1992

Sagittal split osteotomy fixed with biodegradable, self-reinforced poly-L-lactide screws. A pilot study in sheep.

Self-reinforced poly-L-lactide (SR-PLLA) screws were used to fix bilateral mandibular sagittal split osteotomies (SSO) in six sheep. No intermaxillary fixation was used postoperatively. The follow-up time was 16 weeks, after which the sheep were killed. Both sides of the mandible were photographed and radiographed. The bending strength of the osteotomy was measured on the left side of the mandible. Histological and microradiographic studies were performed on the right side of the mandible. The results showed that the SR-PLLA screws were strong enough to fix the SSO rigidly. The bending force needed to break the bone was greater than that for the average unoperated mandible. The histological and microradiographic studies showed uneventful healing of the osteotomies in all six sheep. The results indicate that this method should be suitable for rigid fixation of SSO and fractures of the mandible in human beings.

Animals↗

PubMed1992

A new method of reconstruction in a patient undergoing bilateral total maxillectomy.

A new application of the titanium hollow screw reconstruction plate (THORP) system, originally designed for bridging mandibular defects, is presented. Because of the screw-plate locking principle, the system allows rigid fixation of the plate without unphysiologic load to the bone underneath. A case is presented with a large squamous cell carcinoma requiring bilateral total maxillectomy. The titanium plate was attached horizontally to the zygomatic bones with two titanium hollow screws on each side. Six months later a prosthetic device was constructed and attached to the exposed part of the plate by a modified bar and clips system. The patient is able to speak, chew, and swallow without difficulty.

Aged↗

PubMed1992

Tumour markers and radiological examinations in the follow-up of patients with oral cancer.

In 1986, a new follow-up programme for patients with oral cancer was introduced in our department. The follow-up programme included liver function tests, tumour markers and radiological examination. 63 patients were monitored to the end of 1990. The results showed that serum Carcinoembryonic Antigen (CEA) assays were not sensitive enough to detect early cancer, recurrences or metastases. Neither was there any difference between the preoperative CEA levels of patients with and without recurrence during follow-up. The levels of salivary CEA, were similar to those of healthy individuals. Serum CA 19-9 values were consistently normal. In 1 patient, the first sign of liver metastases was a high 5-nucleotidase level. No recurrences were detected by radiological examination. In conclusion, the importance of frequent and careful clinical observation is emphasized; all 20 recurrences at the primary site and in local lymphnodes were detected by clinical examination. For detection of oral cancer recurrences, several laboratory and radiological examinations seem unnecessary. The cost-benefit of those examinations is significantly low.

5'-Nucleotidase↗

PubMed1992

Different patterns of mandibular fractures in children. An analysis of 220 fractures in 157 patients.

157 paediatric patients with a total of 220 mandibular fractures were evaluated retrospectively. All patients had been examined with the aid of orthopantomography. 72% of the children had fractures in the condylar region. The patients were divided into four age groups according to the development of the dentition (group A: 0-5 years, B: 6-9 years, C: 10-12 years, and D: 13-15 years). Bicycle accidents and falls were the two main causes of the fractures in all age groups. However, there were significant differences in the causes and location of the fractures between groups A+B and C+D. The proportion of condylar fractures decreased and the proportion of body and angle fractures increased with increasing age; fractures in the horizontal part of the mandible were mainly observed in groups C and D. Both aetiological factors and fracture patterns in the patients older than 10 years of age resembled those of adults. The differences observed should be taken into consideration in studies concerning mandibular fractures in paediatric patients. In this respect the age limit between the adult and child should probably be lowered significantly.

Accidents, Traffic↗

PubMed1992

A sensitive model system for in vivo monitoring of baculovirus gene expression in single infected insect cells.

We have developed a fast and sensitive system for the in vivo analysis of gene expression in baculovirus infected lepidopteran insect cells. A recombinant baculovirus containing a luciferase gene from the click beetle, Pyrophorus plagiophthalamus, under transcriptional regulation of the polyhedrin gene promoter of Autographa californica nuclear polyhedrosis virus (AcNPV) was used to infect a Spodoptera frugiperda cell line. Recombinant luciferase could be monitored by luminometry in real-time without disruption of the infected cells, allowing detection of synthesis as early as one hour after infection. The range of luminescence measurements was normally over four orders of magnitude, and the kinetics of luciferase synthesis and the levels of light produced in vivo closely correlated with the expression of polyhedrin in AcNPV infected cells when analyzed by SDS-PAGE. Additionally, single infected cells could be identified by CCD image analysis and flow cytometry.

Animals↗

PubMed1992

Elevated plasma levels of neuropeptide Y upon electrical stimulation of the sympathetic chain in humans.

Neuropeptide Y (NPY) a potent vasoconstrictor peptide, is co-stored with the classic neurotransmitter noradrenaline (NA) in certain peripheral sympathetic neurons and has been suggested to be a co-transmitter in vascular control. Surgical interruption of the sympathetic nerve supply of the upper extremity was performed to treat palmar hyperhidrosis in five patients. Intraoperative electrical stimulation (10 Hz; 0.5 ms; 0.5-3.0 mA) of the right and left sympathetic chains for 1 min was employed to determine the correct level for surgical excision. Blood pressure and heart rate were recorded continuously. Blood was sampled from the antecubital vein on the side subjected to stimulation for the determination of NPY-like immunoreactivity (LI) and plasma catecholamines. Blood samples were collected before and during stimulation, as well as 30 s and 2, 5, and 10 min after stimulation. A maximal blood pressure response was observed during the stimulation, but the magnitude varied markedly and was independent of the side on which the sympathetic chain was stimulated. During 3 of the 10 stimulations, the mean arterial blood pressure (MABP) increased 5-10 mm Hg, while in the other 7 an increase of 30-75 mm Hg was seen. No significant changes in heart rate or plasma adrenaline were found. The peak increase in NPY-LI plasma levels was noted 2 or 5 min after stimulation, while the corresponding peak for NA occurred during or 30 s after the stimulation. The maximal changes in plasma NPY-LI and NA were significantly correlated with the changes in blood pressure (NPY-LI, r = 0.80, p <0.01; NA, r = 0.84, p <0.01) as well as with each other (r = 0.95; p <0.001). It is concluded that, after electrical stimulation of the sympathetic chain in humans, plasma levels of both NPY-LI and NA rise, indicating release of these substances from sympathetic neurons. It is therefore possible that the vasoconstrictor peptide NPY is involved, together with NA, in the blood pressure response elicited by the stimulation.

Journal Article↗

PubMed1992

Normal mouse serum-derived factor(s) which inhibits growth of the interleukin-2-dependent cell line CTLL.

Evidence is presented for the existence of a serum factor(s) (SF), which inhibits the growth of both the interleukin-2 (IL-2)-dependent cell line CTLL and the 2-day generation of CTL cells. This activity is found in the serum of both nude and euthymic mice and its suppressive effect can be detected about 18 hours after addition to CTLL cultures. The inhibitory activity elutes from a Sepharose 6B gel after the gamma globulin fraction (100-150 kD), and is precipitated by ammonium sulfate at 60 w/v% saturation. IL-3-mediated bone marrow colony formation is not inhibited by SF. It also does not suppress the growth of a panel of different tumor cell lines. The spleen cell responsiveness to both Con A and LPS activation is greatly reduced in the presence of SF. However, binding of radiolabelled IL-2 to CTLL cells was not blocked by SF, although the activity was greatly reduced by absorption to these cells. Our data support the existence of factor(s) in sera that may have a regulatory role on IL-2-mediated functions.

Animals↗

PubMed1992

Mandibular reconstruction with free bone grafts.

The ideal method for replacing lost mandibular bone would be to induce growth of host replacement bone that could bridge a defect by means of bone induction. In the coming years, both bone morphogenetic protein and guided tissue regeneration will certainly gain a lot of interest. For the time being, the best method of grafting is still autogenous bone, provided there is a suitable donor site, sufficient bone, and a vascularized graft bed. This review outlines different sources and methods for bone grafting. The possibility of using different substitutes for bone is also discussed, as a number of articles have recently dealt with this problem.

Alveolar Ridge Augmentation↗

PubMed1991

Interleukin-4 downregulates the p70 chain of the IL-2 receptor on peripheral blood mononuclear cells.

Data that support a differential regulation of the interleukin-2 receptor (IL-2R) alpha-(p55 or Tac) and beta-chain (p70) expression by IL-4 are presented. Cytofluorometric analysis performed on peripheral blood mononuclear cells, some of which had been nylon wool passed (enriched for T-cells), in the presence or absence of phytohemagglutinin (PHA) or OKT3, demonstrated that IL-4 has a dose-dependent capacity to inhibit beta-chain IL-2R expression, whereas the alpha-chain is nearly unaffected. We could also, as a consequence of the decreased p70 expression, detect a slight increase in the amounts of IL-2 obtained from PHA-stimulated cultures, when IL-4 was present. Further, the proliferative response, especially to IL-2, but also to PHA alone, was depressed in the presence of IL-4. These data thus give further support to the idea that not only the IL-2R complex as such, but also the two individual IL-2R chains, can be independently regulated.

Dose-Response Relationship, Drug↗

PubMed1991

Severe bone resorption and osteoarthrosis after miniplate fixation of high condylar fractures. A clinical and radiologic study of thirteen patients.

Thirteen cases of high condylar fracture treated by open reduction and fixation with miniplates were monitored for an average of 18 months postoperatively. Satisfactory functional results were achieved clinically in all but one patient. Radiologically, however, signs of condylar resorption and osteoarthrosis were diagnosed in all patients. In four patients with associated multiple fractures of the facial bones, rapid complete resorption of the condyle was observed. These changes were markedly more severe than those observed in our previous study, in which osteosynthesis was performed by transosseous wiring and subsequent intermaxillary fixation for 3 to 7 weeks. Indications for rigid and nonrigid fixation in the surgical treatment of condylar fractures are discussed.

Adolescent↗

PubMed1991

Inhibition of CD3-induced Ca2+ signals in Jurkat T-cells by myristic acid.

Stimulation of T lymphocytes with antibodies against the T cell receptor/CD3 complex induces within seconds a rise in the concentration of intracellular free Ca2+. Here we show that treatment with 20 microM free myristic acid completely inhibits this Ca2+ signal and the cellular proliferation in Jurkat T cells. Also lauric acid inhibited cell growth while its blocking effect on the Ca2+ signal was weaker than that of myristic acid. Other saturated free fatty acids were inactive. The inhibitory effect of myristic acid could be reversed by the addition of fatty acid free albumin, which will bind the fatty acid. Myristic acid, but not its methyl ester, inhibited both the anti-CD3-induced Ca2+ influx across the cell membrane and Ca2+ release from intracellular stores, but not the formation of inositol phosphates. In contrast, thapsigargin-induced release of Ca2+ from the same intracellular stores was unaffected by myristic acid. Thus, myristic acid specifically blocks T cell antigen receptor-CD3 induced Ca2+ mobilization in T cells.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1991

Evaluation of various treatments for carcinoma of the mandibular region.

Cancers of the mandibular region show the lowest survival rates of all oral cancers. In order to compare the effect of five different modes of treatment (including surgery and/or radiotherapy), a series of 159 patients was analysed. When adjustments were made for age, sex and tumour stage in a log-linear multivariate analysis, no differences between treatments in the 5-year relative survival rates (RSR) could be demonstrated for stage I and II tumours. In stage III and IV tumours, radiation treatment alone resulted in poor survival. Between the other four treatments, all including surgery, no statistically significant differences in the 5-year relative survival rates were found. Radiation therapy as an element in combination therapy may have postponed a recurrence but did not affect the 5-year survival rate. For advanced tumours, mostly responsible for the low overall 5-year RSR, higher survival rates can possibly be achieved by improving surgical treatment of the primary lesion and the neck. At present, however, only earlier diagnosis might significantly increase the survival rates.

Adult↗

PubMed1991

Bridging of mandibular defects with two different reconstruction systems: an experimental study.

To compare two different mandibular reconstruction systems, a 5-cm angular resection was performed in nine adult sheep. The defect was reconstructed using either a classic AO plate or the AO-THORP reconstruction system. The animals were killed 5, 9, and 14 weeks after operation. Serial sections with the plates and screws in place were prepared and studied histologically and with microradiography and fluorescence microscopy. Twenty-six percent of the 2.7-mm AO cortical screws were adequately fixed. The corresponding percentage for AO-THORP hollow screws was 73%. The main advantage of the latter system is the screw-plate locking principle, which allows plate stability to be maintained even if bone is resorbed under the plate. Whether the existence of a screw lumen is an advantage has not yet been established.

Animals↗

PubMed1991

Changes in C-reactive protein associated with surgical treatment of mandibular fractures.

C-reactive protein (CRP) levels were determined in 80 patients (67 male, 13 female), each with a single mandibular fracture in either the symphysis, body, or angle region. All patients underwent osteosynthesis (63 with rigid plate fixation following the AO/ASIF principle, 17 with miniplates). C-reactive protein levels were measured on admission and daily during hospitalization. Preoperative CRP levels (mean, 28.5 mg/L) varied according to the time that had elapsed since injury. After surgery, there was always an increase in CRP level. The level reached its maximum (mean, 73.2 mg/L) on the second day after operation. Postoperative CRP levels were significantly influenced by the time between trauma and surgery. Significant differences were also observed with different types of fixation. Fixation with rigid plates was associated with smaller increases in CRP level than was fixation with miniplates. The location of the fracture, associated condylar fractures, the use of maxillomandibular fixation, the presence or absence of a tooth at the fracture site, and the surgical approach did not affect the CRP levels. The significance of CRP measurement for interpretation of postoperative situations is discussed and examples of cases in which there was infection are described.

C-Reactive Protein↗

PubMed1991

Sensory disturbances associated with rigid internal fixation of mandibular fractures.

Sensory status of the inferior alveolar nerve was monitored in 133 patients with 150 fractures in the region of the mandibular canal treated with rigid internal fixation preoperatively and 6 weeks postoperatively. Eighty-five of the patients were reevaluated on final follow-up at an average of 15.9 months. Preoperative sensory disturbance (58.5%) correlated significantly only with the presence of fracture displacement. The occurrence of postoperative paresthesia (76.0% at 6.2 weeks, 46.6% at 15.9 months) correlated significantly with the degree of mandibular edentulousness. Patients with edentulous mandibles, especially when a compression plate was used, suffered significantly more often from nerve injury than fully dentate patients. The results indicated that the sensory disturbance was caused by the surgical procedure. In contrast to previous assumptions, displacement of the fracture and preoperative sensory status did not correlate with postoperative occurrence of paresthesia.

Adolescent↗

PubMed1991

Infection after rigid internal fixation of mandibular fractures: a clinical and radiologic study.

Of 214 patients with mandibular fractures treated following the AO/ASIF principle of rigid fixation, 13 patients (6.1%) developed postoperative infection. The yearly percentage decreased remarkably during the study period. When rigid fixation became a routine method, the infection rate was as low as the corresponding figure for cases treated with nonstable techniques and maxillomandibular fixation (MMF). All but one of the infected fractures were in the angular region of the mandible. Teeth had been extracted from the fracture line in 9 of the 10 dentulous patients. It was concluded that erroneous techniques had been used in almost all infected cases, because compression could not be achieved when there was an irregular fracture line, an atrophic edentulous mandible, or inadequate stability due to removal of a tooth in the line of fracture. In five patients, successful reoperation was performed using a reconstruction plate. Detailed radiologic examination was useful in assessment of infection and in follow-up.

Adolescent↗

PubMed1991

Reconstruction of orbital floor with polydioxanone plate.

The use of a polydioxanone (PDS) plate for orbital reconstruction was evaluated in 20 patients with various traumatic defects of the orbital floor. The follow-up time was 9 to 45 months (mean 20.4 months). A CT scan was obtained in 13 patients. Radiographic analysis showed that in 12 of the 13 patients there was new bone in the orbital floor. Clinically, most patients had transitory postoperative diplopia (lasting for a mean of 29 days) because of overcorrection. Only 2 patients, however, suffered from persistent diplopia. In one patient, abducens nerve paresis was the cause. It is concluded that PDS is suitable for orbital floor reconstruction, at least in cases in which defects do not exceed 1-2 cm in diameter. Overcorrection seems necessary. The material is well tolerated, is totally absorbed and appears to be replaced by bone in nearly all cases.

Absorption↗

PubMed1991

Effect of antiseptic mouthwashes on some clinical and microbiological findings in the mouths of lymphoma patients receiving cytostatic drugs.

51 patients suffering from Hodgkin's disease or non-Hodgkin's lymphoma participated in this double-blind, cross-over study in which 2 antiseptic mouthwashes were tested for their effects on various periodontal index scores and salivary microbial counts. All patients were receiving combination cytostatic treatment based on methotrexate and doxorubicin. The patients (49 +/- 14 years old, 28 men, 23 women) were allotted at random to 2 groups. One rinsed with a 0.12% chlorhexidine gluconate (CHX) solution, the other with a 0.025% amine-stannous fluoride (AmF + SnF) solution 2x daily for 2 weeks. Both groups then continued rinsing with a 0.05% sodium fluoride (F) solution for 2 weeks, before switching over to AmF + SnF or CHX, respectively. All solutions had been prepared in such a way that they had the same colour and taste. Visible plaque index and gingival bleeding index scores were significantly reduced after periods of rinsing with CHX solution (P less than 0.001) and AmF + SnF solution (P less than 0.05). Microbiological cultivations of saliva specimens revealed significant reductions in mutans streptococci immediately after commencing rinsing, while lactobacilli and yeast counts were not affected.

Amines↗