Green fluorescent protein as a tool for screening recombinant baculoviruses

The gene encoding the green fluorescent protein (GFP) from the jellyfish Aequorea victoria, ligated to the honeybee melittin signal peptide-encoding sequence, 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 recombinant green fluorescent protein was identified by SDS-PAGE gel electrophoresis followed by Coomassie blue staining of lysates from the recombinant baculovirus infected insect cells. Emission and excitation scanning of the recombinant baculovirus infected insect cells gave an emission maximum of 509 nm and excitation maximum of 398 nm. The GFP protein expressed was also detected in infected insect cells by a flow cytometer analysis.

Identification of biotinylated molecules using a baculovirus-expressed luciferase-streptavidin fusion protein

A genetic fusion between streptavidin of Streptomyces avidinii and luciferase of Pyrophorus plagiophthalamus was constructed. The fusion protein was produced in the Sf9 insect cell line using the baculovirus expression vector system (BEVS). Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the proteins from cells infected with the recombinant virus, VL1393-LucGR-StreptAv, revealed that the fusion protein migrated with an apparent molecular weight of 75 kDa. Light emission measurements showed that the infected cells produced about 255 mg of the chimeric protein per liter of cell culture (127.5 micrograms/1 x 10(6) cells). Precipitation of the LucGR-StreptAv fusion protein with biotinylated acrylic beads as well as immunoblot analyses using biotinylated immunoglobulins indicated that both fusion moieties of the chimeric protein product were functional with respect to their physical and enzymatic activities.

Detection of rubella virus-specific immunoglobulin M antibodies with a baculovirus-expressed E1 protein

The structural proteins of rubella virus (RV) were expressed in insect cells by using the baculovirus expression vector system. The recombinant E1 envelope glycoprotein was purified by immunoaffinity chromatography and used to detect RV-specific immunoglobulin M antibodies in a time-resolved fluoroimmunoassay. Correlation analysis between the reactivities of antibodies against this recombinant E1 and the reactivities against authentic RV antigen shows that purified E1 can detect RV antibodies of the immunoglobulin M type.

Opportunistic osteomyelitis in the jaws of children on immunosuppressive chemotherapy

PURPOSE

Four children with an osteomyelitic process in the jaw bones while on cytotoxic chemotherapy were treated by radical surgery and antimicrobial chemotherapy.

PATIENTS AND METHODS

Symptoms (local swelling and pain in the jaw, necrotic gingivitis, and spontaneous loss of teeth) appeared 3 weeks, 4 weeks, and 8 months after diagnosis of leukemia, and 8 days posttransplant in a patient with severe aplastic anemia. Three had the process in the mandible and one in the maxilla. Specific diagnoses of Aspergillus flavus, Saccharomyces cerevisiae, and Actinomyces species were obtained histologically from surgical samples. Treatment was radical surgery to remove all infected and necrotic tissue: removal of a substantial part of the mandible and loss of seven to eight permanent teeth in those with mandibular lesions. Actinomycosis was treated with penicillin for 2 years. The patients with fungal lesions received amphotericin B for 2, 5, and 6 months, with adjuvant itraconazole, fluconazole, or 5-fluorocytosine for 9-12 months. Anti-cancer chemotherapy was continued.

RESULTS

All the bony lesions healed. The patient with acute myeloid leukemia died in relapse 1 year postdiagnosis; her aspergillus osteomyelitis had been inactive for 8 months. The other three patients are alive and well 1.9, 2.1, and 1.9 years after termination of antimicrobial therapy.

CONCLUSIONS

We emphasize the necessity of specific diagnosis from appropriate surgical samples and conclude that in patients undergoing chemotherapy bony lesions caused by opportunistic microorganisms may be curable with aggressive surgery and prolonged medication.

Lag-screw osteosynthesis of mandibular condyle fractures: a clinical and radiological study

PURPOSE

This study evaluates the clinical and radiologic results after open reduction and lag-screw osteosynthesis of fractured mandibular condyles.

MATERIALS AND METHODS

Eleven adult patients underwent surgery for displaced or dislocated mandibular condyle fractures via a submandibular approach. The repositioned fragments were fixed using lag screws designed by Krenkel or Eckelt. Maxillomandibular fixation was used postoperatively for 2.6 weeks on average (range, 1 to 4 weeks) in nine patients.

RESULTS

Slight transient weakness of the mandibular branch of the facial nerve occurred in three cases. Occlusal adjustment was needed in another three cases. Radiologically, the fracture line disappeared at 22.5 weeks on average (range, 8 to 38 weeks). Three screws had to be removed because of loosening. There were signs that the screws had migrated caudally from their original position in seven cases. Twenty-one months on average after operation (range, 8 to 31 months), patients were satisfied with treatment. Clinically, all patients had a stable occlusion and symmetry of the face. All had greater than 5-mm symmetrical lateral jaw excursions. Ten patients had wide (> 40 mm) painless mouth opening. Healing in malposition occurred in four cases and there was considerable shortening of the mandibular ramus in four cases.

CONCLUSIONS

Despite good clinical results, lag screws do not meet the needs for rigid internal fixation in the treatment of mandibular condyle fractures.

Midfacial fractures in pediatric patients. Frequency, characteristics, and causes

OBJECTIVE

To determine the frequency, characteristics, and causes of midfacial fractures in children.

DESIGN

A retrospective review of the patients' medical charts and radiographs.

SETTING

Tertiary referral center.

PATIENTS

Fifty-four patients under 16 years of age, with midfacial fractures diagnosed and treated in the Helsinki (Finland) University Central Hospital from 1980 through 1992.

MAIN OUTCOME MEASUREMENTS

The data examined included sex, age, time and cause of the accident, type and location of the fractures, the presence and location of associated injuries, complications, and treatment methods.

RESULTS

The male-to-female ratio was 1.16:1. Motor-vehicle accident was the most common cause of injuries. The frequency of injuries was in decreasing order: (1) maxillary alveolar bone, (2) zygoma, and (3) Le Fort fractures of the maxilla. The majority of injuries occurred in subjects who were 13 to 15 years old. In children less than 6 years old, only alveolar fractures occurred. For the other age groups, no significant difference in the fracture pattern was found. No fatalities occurred in this patient series.

CONCLUSIONS

Midfacial pediatric fractures are rare. A high velocity force, such as that from a motor-vehicle accident is a factor producing the injury. Owing to the high impact, associated injuries are common. The severity of the insult is more essential than the age of the patient and the development of the paranasal sinuses.

Rapid Ca2+ mobilization in single LGL cells upon interaction with K562 target cells--role of the CD18 and CD16 molecules

Changes in the intracellular Ca2+ levels of human large granular lymphocytes (LGL), loaded with the fluorescent Ca2+ indicator fura-2, have been studied upon addition of human chronic myelogenous leukemia K562 cells. The measurements, analyzed at the single-cell level using image analysis, indicate a rapid Ca2+ mobilization in the effector cell upon interaction with its target cell. This mobilization appeared to be localized to an area within the effector cell that was in physical contact with target cells. The LGL responded with different kinetics in a transient manner and about 19% of them could undergo two or more responses. Data obtained from experiments performed with anti-CD16- and anti-CD18-pretreated LGL in the presence of target cells indicate that the CD16 and CD18 molecules are not likely to be the triggers of the Ca2+ response, although they might participate in the recognition of the target cell.

Expression of the human interleukin-2 receptor gamma chain in insect cells using a baculovirus expression vector

The gene encoding the gamma-chain of the human Interleukin-2 receptor was expressed in lepidopteran insect cells using the baculovirus expression vector system. The corresponding gene was inserted under the polyhedrin promoter of the Autographa californica nuclear polyhedrosis virus and expressed in the Spodoptera frugiperda insect cell line Sf9 during viral infection. The recombinant receptor protein was identified by immunoblotting in cell lysates, prepared from insect cells infected with the recombinant virus. At 40 h post infection the corresponding protein was detected as two major bands with apparent molecular weights of 50-60 kDa using a rabbit anti-human IL-2R gamma-receptor specific antiserum. Metabolic labelling with [35S]-methionine and SDS-PAGE analysis of the recombinant baculovirus infected insect cells verified the immunoblotting data. The expressed IL-2R gamma- protein could also be determined on the surface of infected insect cells by flow cytometer analysis.

Synthesis and processing of the rubella virus p110 polyprotein precursor in baculovirus-infected Spodoptera frugiperda cells

In order to study the processing of rubella virus (RV) structural proteins (capsid protein, of 33 kDa; E2 of 42-47 kDa; and E1 of 58 kDa) in Spodoptera frugiperda (fall armyworm) cells, a 24S cDNA encoding the polyprotein precursor, p110, was inserted under the transcriptional regulation of the polyhedrin gene promoter of the Autographa californica nuclear polyhedrosis virus (AcNPV) and expressed during viral infection. By immunoblot analysis using antibodies directed against whole RV and the individual structural proteins, evidence is presented that polypeptides similar to those synthesized in RV-infected B-Vero cells are expressed in this lepidopteran insect cell line infected with the recombinant baculovirus, VL1392-RV24S. The identity of the recombinant proteins was further confirmed using human convalescent sera. By expressing the recombinant proteins in the presence and absence of tunicamycin, we have further demonstrated that the 24S transcription-translation unit of RV, is expressed and proteolytically cleaved similarly, if not identically, in Sf9 cells as compared to B-Vero cells.

Neuromuscular dysfunction after surgical treatment of oral cancer

Surgical treatment of oral cancer usually includes radical dissection of the neck, in which the sternocleidomastoid muscle is sacrificed. In modified neck dissection the accessory nerve is spared, but may be severed by e.g. manipulation. The facial nerve may also be severed by traction or distension. We have done an electromyographic study of 35 patients, 20 men and 15 women, aged from 21 to 92 yrs, 6 to 176 months after oral cancer operation. EMG findings of the upper trapezius muscle were normal in only six of 32 patients who had had a radical or upper neck dissection, although the accessory nerve had been identified and spared during surgery. The surgeons' evaluation of the risk to the facial nerve was in good correlation to EMG findings, both the orbicularis oris and the mentalis muscle were better preserved, if the risk was considered minor. The loss of motor units in voluntary contraction and the nerve latencies to the muscles were in good correlation to many factors from the spectral analysis of the EMG, e.g. to the root mean square (RMS), to the mean rectified value (MRV), to the mean amplitude and to the number of turns. The accessory nerve is easily damaged, and the injury is often not noted during neck dissection. Significant problems may also arise with lesions of the facial nerve. Quantitative EMG analysis may add to sensitivity of the postoperative EMG studies.

Immunoaffinity purification of baculovirus-expressed rubella virus E1 for diagnostic purposes

Three monoclonal antibodies, termed 4E10, 1E11:10, and 2D9:1, were generated against rubella virus. Immunoblot analysis with purified authentic rubella virus or recombinant baculovirus-expressed rubella virus structural proteins E1, E2, and C demonstrated that they were directed against the E1 envelope glycoprotein of the rubella virus particle. By using the yeast Ty virus-like particle system, it was possible to map the binding site of 1E11:10 within amino acids 236 to 286 of the E1 protein and the binding sites of 2D9:1 and 4E10 outside this region. Immunoaffinity purification with these monoclonal antibodies made it evident that they are useful for obtaining large quantities of pure baculovirus-expressed rubella virus envelope protein E1. The diagnostic potential of this immunoaffinity-purified recombinant rubella virus E1 protein compared with that of authentic rubella virus is demonstrated.

Blindness after maxillofacial blunt trauma. Evaluation of candidates for optic nerve decompression surgery

Clinical and computerized tomography (CT) findings in 10 patients with post-traumatic blindness after maxillofacial blunt trauma were evaluated as potential candidates for optic nerve decompression surgery. The total number of blind eyes was 14. All patients suffered from midfacial fractures (isolated zygomatic fracture in 4 and Le Fort fracture in 6 cases) predominantly caused by road traffic accidents. CT scanning and clinical findings allowed location of damage to the optic nerve region in all patients. The most common CT finding was swelling of the optic nerve. Fracture in the optic canal wall was seen in only 3 cases. The clinical situations characteristic of this type of injury make diagnosis and early surgical intervention difficult. It was concluded that two of the 10 patients might have benefitted from optic nerve decompression.

Analysis of possible factors leading to problems after nonsurgical treatment of condylar fractures

PURPOSE

An attempt was made to identify types of condylar fractures that, despite active nonsurgical treatment, lead to unsatisfactory clinical results.

PATIENTS AND METHODS

Ninety-two dentate adult patients with unilateral condylar fractures were studied clinically and radiologically. On the basis of the information collected, problematic cases were identified. These consisted of patients with persistent occlusal change and/or marked deviation of the mandible on mouth opening after removal of maxillomandibular fixation or during follow-up. Radiologic analyses were performed using panoramic and Towne's views, and the results of problematic and nonproblematic cases were compared.

RESULTS

Using clinical parameters, two problem groups were found. In patients with persistent malocclusion, ramus height was significantly reduced, irrespective of degree or direction of angulation between the fragments. Deviation of the jaw on mouth opening, but no occlusal disturbances, occurred in those with dislocated condyles.

CONCLUSION

Problematic condylar fractures can often be identified preoperatively by means of simple radiographic measurements and these cases should probably be treated surgically.

Sagittal ramus osteotomies fixed with biodegradable screws: a preliminary report

Nine patients underwent bilateral sagittal split osteotomies of the mandible. The osteotomies were fixed using two self-reinforced poly-L-lactide screws. No maxillomandibular fixation was used postoperatively. The preliminary results with the shortest follow-up of 15 months show that primary healing was normal. No late-term clinical complications were encountered during the follow-up, the longest of which is now 23 months.

The effect of osteotomy and osteosynthesis in the mandibular condyle. A radiologic and histologic study in sheep

Eighteen oblique osteotomies in sheep mandibular condylar necks were fixed with self-reinforced poly-L-lactide (SR-PLLA) (n = 9) or stainless steel (n = 9) screws (core diameters 2.4, 2.7, 3.0, or 3.5 mm). No intermaxillary fixation (IMF) was applied. The follow-up periods were 6, 12, and 24 weeks, respectively, after which the sheep were killed, and the status of the condylar head was assessed radiographically and histologically. The results showed that the fixation had been adequate. Bony destruction, osteophytes, and flattening of the condylar head, however, were frequently observed in both groups, as compared with the unoperated contralateral condyle. Histologic studies revealed that the thickness of the condylar head cartilage had increased and that the boundaries of the different cell layers were irregular, as was the junction of cartilage and bone. The diameter of the screw did not seem to have any influence on the occurrence of either radiologic or histologic signs of condylar degeneration. These findings indicate that screw fixation of condylar fractures in the mandible without IMF might result in degenerative joint disease.

Gingival and dental status, salivary acidogenic bacteria, and yeast counts of patients with active or inactive Crohn's disease

To investigate dental, gingival, and salivary aspects during an exacerbation of Crohn's disease, 53 patients with long-standing Crohn's disease were clinically, endoscopically, and radiologically examined. The patients were divided in two groups: 32 patients had active disease and 21 patients had inactive disease. Oral examination of the patients did not reveal any statistically significant differences in gingival or dental indexes between the groups, but patients with active disease tended to have higher scores of gingivitis than patients with inactive disease despite the fact that the patients with active disease were younger than those in remission. No differences between the groups were observed in salivary flow rate or buffering capacity. Lactobacilli and yeast counts of saliva tended to be higher among patients with active disease than with inactive disease, but the difference between the groups was significant only for high mutans streptococci counts.

Effect of anticancer drugs on patients with and without initially reduced saliva flow

We reported earlier that despite the well-known cytolytic effect of anticancer drugs, mean stimulated salivary flow rates were not significantly affected during a 12-month follow-up of patients undergoing treatment for lymphomas (Laine et al. Oral Oncol, Eur J Cancer 1992, 28B, 125-128). Therefore, we set out to investigate in more detail the flow rates and composition of salivas in these patients, but now grouped according to their initial flow rate values, which had been assessed before the start of treatment. 49 patients of the original material (30 men and 19 women, mean age 49.9 years) were divided into hyposalivation and normal flow rate groups, according to their baseline values. Stimulated saliva flow > or = 0.8 ml/min was regarded as the limit for a normal flow rate. 11 patients were found to have reduced flow at baseline (hyposalivation group), while 38 patients had normal flow rate. Analysis of repeated saliva samples taken during the 12-month follow-up showed that flow rates remained significantly lower in the hyposalivation group compared with those of the other group (P < 0.001). Further, the concentrations of total protein, albumin, lysozyme, amylase, IgG, IgA and IgM were, and remained, all significantly higher in patients of the hyposalivation group. Counts for salivary mutans streptococci and yeasts were higher and remained significantly so among patients with hyposalivation than among those with normal flow rate while lactobacilli counts were higher in patients with normal initial flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)