Fusion of genes encoding Escherichia coli heat-stable enterotoxin and outer membrane protein OmpC.

The OmpC outer membrane protein of Escherichia coli was used as a carrier molecule for the nonimmunogenic heat-stable enterotoxin STa. Two fragments of different lengths of the gene encoding STa were fused in vitro to the 3' terminus of the truncated ompC gene. The resulting OmpC-STa hybrid proteins could be detected by L-[35S]cysteine labeling, and they were processed and thus exported. All synthesized hybrid protein remained cell bound and was found by fractionation mainly in the periplasm. Immunoblot analysis showed that the hybrid proteins reacted in vitro both with anti-OmpC and anti-STa antibodies, and immunization of rabbits evoked an antibody response to either of these proteins.     

Diagnostic tools in respiratory tract infections: use and comparison with Finnish guidelines

The objectives of this prospective epidemiological study were to describe the diagnosis and treatment of respiratory tract infections by Finnish general practitioners and to compare current practice with national evidence-based guidelines. All patients (n = 4386) seeking primary care for a respiratory tract infection for the first time in 30 health centres during 1 week in November 1998 participated in the study. The main outcome measures were the amounts and types of diagnostic tests used and antimicrobials prescribed. Tympanometry was used in 1% of patients with acute otitis media. Ultrasonography, sinus radiography or both were used in 80% of cases of sinusitis and antigen detection or culture for Streptococci in 57% of throat infections. In acute bronchitis, a chest radiograph was taken in 5% of cases and the CRP level determined in 8%. The corresponding figures for pneumonia were 49% and 39%. In pneumonia and throat infection, diagnostic testing was statistically significantly associated with the use of antimicrobials, but not in otitis, sinusitis or acute bronchitis. Diagnostic tests were underused in respiratory tract infections compared to evidence-based recommendations.     

Development of the spontaneous activity transients and ongoing cortical activity in human preterm babies

Recent experimental studies have shown that developing cortex in several animals species, including humans, exhibits spontaneous intermittent activity that is believed to be crucial for the proper wiring of early brain networks. The present study examined the developmental changes in these spontaneous activity transients (SAT) and in other ongoing cortical activities in human preterm babies. Full-band electroencephalography (FbEEG) recordings were obtained from 16 babies at conceptional ages between 32.8 and 40 wk. We examined the SATs and the intervening ongoing cortical activities (inter-SAT; iSAT) with average waveforms, their variance and power, as well as with wavelet-based time-frequency analyses. Our results show, that the low frequency power and the variance of the average waveform of SAT decrease during development. There was a simultaneous increase in the activity at higher frequencies, with most pronounced increase at theta-alpha range (4-9 Hz). In addition to the overall increase, the activity at higher frequencies showed an increased grouping into bursts that are nested in the low frequency (0.5-1 Hz) waves. Analysis of the iSAT epochs showed a developmental increase in power at lower frequencies in quiet sleep. There was an increase in a wide range of higher frequencies (4-16 Hz), whereas the ratio of beta (16-30 Hz) and theta-alpha (4-9 Hz) range activity declined, indicating a preferential increase at theta-alpha range activity. Notably, SAT and iSAT activities remained distinct throughout the development in all measures used in our study. The present results are consistent with the idea that SAT and the other ongoing cortical activities are distinct functional entities. Recognition of these two basic mechanisms in the cortical activity in preterm human babies opens new rational approaches for an evaluation and monitoring of early human brain function.     

Surgical anatomy of the internal auditory canal. A temporal bone dissection study

The suboccipital fossa approach to the fundus of the internal auditory canal (IAC) at acoustic neurinoma surgery was investigated in 32 temporal bones. A microdissection was done under the operating microscope in a specially constructed holder so that the surgeon's exposure and angles of view through the craniotomy were mimicked. It was possible to obtain an unobstructed view of the transverse crest and the vestibular nerves in all specimens without the bony labyrinth being opened in the process. A prerequisite was that, as the posterior wall of the IAC was removed, drilling did not extend lateral to a line running through the midpoint of the craniotomy to the transverse crest. The distances of major structures from the posterior and superior pyramid surface were measured, using a special impression technique that made it possible to measure the thickness of the bony layer removed.     

Inflammatory cells in chronic middle ear disease. Value of lymphocyte subset determination in ear surgery

Lymphoid cell subsets were studied in biopsy specimens of uninfected and infected ear canal epidermis, tympanic membrane, cholesteatoma epithelium, and middle ear and antrum granulation tissue. All specimens showing uninfected squamous epithelium, including those of cholesteatoma membrane, contained only a few lymphoid cells. Biopsies of infected squamous epithelium showed enhanced Ts/c activity in the subepithelial layer. Granulation tissue showed normal Th/i activity. B-cells and NK cells appeared in small numbers. Lymphoid cell subset analysis is indicated in ears reconstructed with allograft material to detect signs of rejection. It is of little value in cases of chronic inflammatory middle ear disease which have not previously been operated upon.     

Pneumococcal antigens and endotoxin in effusions from patients with secretory otitis media

Counterimmunoelectrophoresis revealed pneumococcus capsular polysaccharide antigen in 16% of 108 effusions from chronic secretory otitis media (SOM). Pneumococci were cultured from the effusion in only 1%. In an additional series of 23 SOM ears, only 4.3% were antigen-positive. Tests by means of pneumococcal coagglutination and C-polysaccharide detection gave identical results. Endotoxin was detected in 76% of the specimens. Control tests with aggregated NHS, IgG and IgA diluted 1: 10 were invariably positive. It appears that endotoxin positivity in SOM fluids results from the presence of activated immunoglobulins, most probably dimeric IgA, in the secretion, and so allows no conclusions as to the bacterial etiology of SOM.     

Surgical treatment of chronic middle ear disease. II. Canal wall up and canal wall down procedures

Results of canal wall up (CWU) and canal wall down (CWD) tympanomastoid one-stage surgery were evaluated in 268 ears. In the CWU group of 121 ears, 50 ears (41%) had clinical cholesteatoma, whereas cholesteatoma was present in all 147 ears operated upon by the CWD technique. The disease was much less severe in the former group, which, for instance, showed no labyrith fistula, as compared with 17 (12%) in the latter group. Extensive disease also accounts for the larger number of complications seen in the CWD group. Average hearing levels postoperatively in the CWU group were significantly better than preoperatively. In the CWD group the preoperative levels were maintained. Recurrence of cholesteatoma was noted in 2% in the CWD group, while one implantation cholesteatoma occurred in the CWU group. Of the many surgical procedures available, the one offering the best means of curing the disease should of course be chosen. Ossicular repair with bone offers good prospects of a successful one-stage reconstruction.     

Surgical treatment of chronic middle ear disease. 1. Myringoplasty and tympanoplasty

Results of myringoplasty or tympanoplasty were evaluated in 225 ears followed for at least one year after surgery. Repair of the tympanic membrane with an underlay connective tissue graft (fascia in 90%) was successful in 97% of the ears. One late perforation developed 3 years postoperatively. The average postoperative air-bone gap was 4.8 dB in 88 cases of myringoplasty, the series including three ears with a rigid footplate. Rigid incus and malleus should not be mobilized but subjected to resection and reconstruction. Poor tubal function caused adhesive changes in one ear (1%). In tympanoplasty the average postoperative air-bone gap was 11.3 dB in 100 ears with stapes present and 20.6 dB in 36 ears with only the footplate remaining. Of the 137 tympanoplasty ears, 10 (7%) showed prominent adhesive changes. In 36 ears with cholesteatoma there was one recurrence 3 years later (3%). An air-bone gap of less than 20 dB was postoperatively noted in 94% of the ears undergoing myringoplasty and in 69% of the ears undergoing tympanoplasty.     

Histopathological observations on polyethylene-type materials in chronic ear surgery

Proplast implants were used in reconstruction of the posterior ear canal wall in one ear and in obliteration of the cavity in two ears. All ears healed well but the canal wall implant became visible in 15 months and had to be removed because of persistant suppuration. The other two implants became visible 3 to 4 years postoperatively. Plastipore TORPs were implanted in two ears undergoing revision surgery. One prosthesis was removed several months later because of infection, and the other 1 year after surgery, as no improvement in hearing had been achieved. Histologically, masses of giant cells were seen in the implants and many cells had engulfed both the vitreous carbon material of Proplast and the white Teflon material of both Proplast and Plastipore. It is concluded that Proplast is unsuitable either for canal wall reconstruction or for cavity obliteration. Plastipore should be used only as a bridge between two ossicles. If the implant must be applied to the tympanic membrane, that end should be fitted with a nonabsorbable bony homograft, which does not cause foreign body reaction.