Longitudinal follow-up of tinnitus complaints.

OBJECTIVE: To investigate the long-term outcome of patients with tinnitus, the long-term effects of cognitive behavioral therapy, and what properties of tinnitus predict distress at follow-up. DESIGN: A longitudinal follow-up of a consecutive sample of patients with tinnitus initially seen by a clinical psychologist. SETTING: Department of Audiology, University Hospital, Uppsala, Sweden. PARTICIPANTS: A consecutive series of 189 patients with tinnitus treated between January 1988 and March 1995 were sent a postal questionnaire booklet. One hundred forty-six (77 women and 69 men) provided usable responses, in all yielding a 77% response rate. MAIN OUTCOME MEASURES: A questionnaire was derived from a structured interview "Questions About Your Tinnitus." Also included were the Tinnitus Reaction Questionnaire and tinnitus-matching data. RESULTS: Questionnaire data showed that many patients with tinnitus still experienced distress an average of 4.9 years after admission. Tolerance of tinnitus increased over time overall. For patients who had received cognitive behavioral therapy (59%), there was a reduction in tinnitus-related distress. Further, an open-ended question showed that the benefits from treatment outnumbered the deficits. Multiple regression analysis showed that tinnitus maskability at admission was a significant predictor of distress at follow-up. CONCLUSIONS: Severe tinnitus shows some signs of improvement over time, especially when psychological treatment has been given. Tinnitus maskability is an important prognostic factor of future tinnitus annoyance.

Alternative surfaces for microcarrier culture of animal cells.

As part of an effort to broaden the applicability and efficiency of microcarrier cell culture various alternative new microcarriers were synthesized. The microcarriers were compared as substrates for the growth of several types of cells and with respect to binding of proteins from the culture medium. Cross-linked dextran has been found to be the most suitable material for a microcarrier matrix and was used as the matrix for the new microcarriers. One type of microcarrier was synthesized so that the charges necessary for cell attachment were present only in the surface layer of the microcarrier in the form of N,N,N-trimethyl-2- hydroxyaminopropyl groups. The resulting microcarriers had a very low capacity to bind proteins from the culture medium (e.g. albumin and IgG) and such proteins could be removed from the cultures more efficiently than when using previous microcarriers. A new principle was used for the development of the other type of microcarrier. A surface layer of cross-linked denatured collagen provided the surface for growth of cells. These microcarriers provided a "natural" substrate for cell growth and allowed improved attachment and spreading of cells with epithelial morphology. Harvesting cells from these microcarriers with proteolytic enzymes was more efficient than with previous microcarriers. The two alternative microcarriers should result in improved process efficiency and have a potential value in the preparation of live vaccines.

Alternative surfaces for microcarrier culture of animal cells.

As part of an effort to broaden the applicability and efficiency of microcarrier cell culture various alternative new microcarriers were synthesized. The microcarriers were compared as substrates for the growth of several types of cells and with respect to binding of proteins from the culture medium. Cross-linked dextran has been found to be the most suitable material for a microcarrier matrix and was used as the matrix for the new microcarriers. One type of microcarrier was synthesized so that the charges necessary for cell attachment were present only in the surface layer of the microcarrier in the form of N,N,N-trimethyl-2-hydroxyaminopropyl groups. The resulting microcarriers had a very low capacity to bind proteins from the culture medium (e.g. albumin and IgG) and such proteins could be removed from the cultures more efficiently than when using previous microcarriers. A new principle was used for the development of the other type of microcarrier. A surface layer of cross-linked denatured collagen provided the surface for growth of cells. These microcarriers provided a "natural" substrate for cell growth and allowed improved attachment and spreading of cells with epithelial morphology. Harvesting cells from these microcarriers with proteolytic enzymes was more efficient than with previous microcarriers. The two alternative microcarriers should result in improved process efficiency and have a potential value in the preparation of live vaccines.

A rapid method for purification of human granulocytes using percoll. A comparison with dextran sedimentation.

A simple one-step method for purification of human granulocytes, based on the use of a discontinuous gradient of Percoll, is described. The cell yield is 55% and the purity of the granulocyte fraction is 97%. The cells' ability to exclude trypan blue and phagocytic function are not altered during the purification process. We conclude that centrifugation in Percoll is superior to conventional dextran sedimentation; it is also less time-consuming.

Microcarriers for animal cell culture: a brief review of theory and practice.

Microcarrier beads for animal cell culture are considered in relation to aspects of cell adhesion and growth. Some "critical parameters" for a successful microcarrier are discussed, comparing currently available materials. The properties most critical for a successful microcarrier were closely fulfilled by the microcarrier CytodexTM 1 which has been used for the successful cultivation of more than 60 different cell types. Cytodex 1 has been used for the culture of primary cells, normal diploid cell strains and established or transformed cell lines in culture volumes ranging from a few millilitres to over 100 litres.

The isolectins of Helix pomatia. Separation by isoelectric focusing and preliminary characterization.

Helix pomatia lectin was fractionated into several (at least 12) components by isolectric focusing in PharmalyteTM. Eight of these were recovered from a preparative column experiment and shown to be essentially pure by analytical electrofocusing in polyacrylamide gel slabs. The lectin components had haemagglutinating activity against human group A erythrocytes and similar molecular weights of 80 000 as determined vidual components showed slight variations in composition. The components are considered to be isolectins. Isoelectric focusing of lectin samples prepared from single snails from two different biotopes showed isolectin patterns similar to that of pooled lectin. Gel filtration of the lectin and flat bed electrofocusing of isolated isolectins both in the presence of 6 M ura, indicated that the lectin molecules are formed by different combinations of a range subunits with similar molecular weight but with different isoelectric points.

The use of wheat-germ lectin-Sepharose for the purification of human haemopexin.

Haemopexin was prepared in 37% yield from normal human serum by a simple procedure involving fractional poly(ethylene glycol) precipitation and subsequent chromatography on DEAE-Sepharose CL-6B. One peak from the ion exchanger consisted of only haemopexin and transferrin. These proteins were separated by chromatography on wheat-germ lectin-Sepharose 6MB. Haemopexin was selectively bound and was subsequently desorbed by N-acetyl-D-glucosamine. No impurities could be detected in the final preparation by immunoelectrophoresis or by immunodiffusion against a range of antisera. The protein gave two partially separated bands in polyacrylamide-gradient-gel electrophoresis, corresponding to apohaemopexin and haem-haemopexin complex.

Purification of lectins by biospecific affinity chromatography.

Biospecific adsorbents which can be used for the purification of lectins are easily prepared by a one-step reaction between Epoxy-activated Sepharose 6 B and lectin-specific sugars. This paper reports the immobilization of N-acetyl-D-galactosamine and N-acetyl-D-glucosamine and the use of the resulting Sepharose derivatives for the purification of soybean lectin and wheat germ lectin, respectively. The former adsorbent had a maximal capacity of 15 mg of lectin/ml sedimented gel and the yield corresponded to 145 mg of lectin/100 g of soybeans. Similarly, yields of wheat germ lectin corresponding to 65 mg/100 g of wheat germ were obtained on an adsorbent which bound 10 mg of lectin/ml. The purified lectins were homogeneous as judged by electrophoresis in polyacrylamide gels at pH 4.5.