Preventing glycaemic relapse in recently controlled type 2 diabetes patients: a randomised controlled trial.

AIMS/HYPOTHESIS: After achieving glycaemic control, many type 2 diabetic patients relapse to clinically significant levels of hyperglycaemia. We sought to determine the optimal frequency of telephone contact by nurse practitioners that was necessary to prevent glycaemic relapse. METHODS: This parallel, randomised controlled trial ran from June 2002 to February 2006 at an academic medical centre, studying 164 type 2 diabetic patients who had recently achieved glycaemic control. Participants were randomly assigned by sequential, concealed, computer-generated allocation to a 2 year maintenance strategy consisting of: (1) routine follow-up (n = 54); (2) routine follow-up and quarterly telephone contact (n = 55); or (3) routine follow-up and monthly telephone contact (n = 55). Blinding was not possible. The primary outcome was cumulative incidence of glycaemic relapse, defined as an increase in HbA(1c) of > or =1%; all participants were analysed. Cumulative incidence and prevalent proportions were compared. Weight change and hypoglycaemia were also assessed. RESULTS: All participants randomised were included in the analyses. The study was completed by 90% of participants and intervention fidelity was high. At 24 months, the cumulative incidence of relapse was 41%. At 12 months, prevalent proportions of relapse were 20%, 14% and 15% for control, quarterly contact and monthly contact, respectively. At 24 months, they were 25%, 21% and 29%, respectively. There was no statistically significant difference in cumulative incidence or prevalent proportions of relapse among the study arms. Adverse events did not differ between study arms. CONCLUSIONS/INTERPRETATION: This first randomised controlled trial to test an intervention to prevent glycaemic relapse found that regularly scheduled telephone contact by a nurse practitioner was no more effective than routine follow-up care in preventing glycaemic relapse.

Cross-neutralization tests among Cache Valley virus isolates revealing the existence of multiple subtypes.

Maguari virus has been classified as a subtype of Cache Valley virus. Seven Bunyamwera serogroup viruses (including prototypes Cache Valley and Maguari viruses), 4 viruses shown in previous tests as close antigenic relatives of Maguari or Cache Valley viruses, and Xingu virus were cross-tested by serum dilution-plaque reduction neutralization. All viruses were distinguishable from prototypes Cache Valley and Maguari viruses. The close antigenic relationships of the Cache Valley-like viruses demonstrate that multiple subtypes of Cache Valley virus exist and suggest that such antigenic variation is a phenotypic expression of considerable genetic diversity.

Reevaluation of the western equine encephalitis antigenic complex of alphaviruses (family Togaviridae) as determined by neutralization tests.

Fourteen viruses closely related to the Fleming strain of western equine encephalitis (WEE) virus were cross-tested by serum dilution-plaque reduction neutralization. The results demonstrate that strains McMillan, R-43738, AG80-646, BeAr 102091, and Y62-33 are subtypes or varieties of western equine encephalitis virus strain Fleming. Ockelbo, Kyzylagach, and Babanki are subtypes of the prototype strain (EgAr 339) of Sindbis virus. Fort Morgan and Buggy Creek viruses are closely related to each other, whereas Highlands J and Aura viruses are distinct from other members of this antigenic complex. There appear to be parallels between geographic distribution and antigenic relatedness. We hypothesize that birds, the principal vertebrate hosts for these viruses, spread the progenitor viruses north and south and from continent to continent. Viruses of the WEE complex with lesser antigenic differences may develop in discrete ecologic conditions.

Antigenic variants of Colorado tick fever virus.

Twenty strains of Colorado tick fever (CTF) virus, isolated from ticks, mammals and humans, and two antigenic relatives of CTF virus were compared in cross-neutralization tests. Viruses were tested using single-inoculation sera prepared in hamsters. Antigenic variation, as measured by differences detected in the neutralization test, was noted among the virus isolates identified as strains of CTF virus. The virus strains isolated from humans appeared to vary the most in serological reactions. The two antigenic relatives of CTF virus are clearly distinct from strains of CTF and are different from each other. Antigenic relationships between these two viruses were established using two sets of single-inoculation antisera and both complement fixation and neutralization tests. Six distinct antigenic variants of CTF virus isolated from humans and the virus strain from ticks (75V1906) that showed the least antigenic variation, were tested against 49 coded serum pairs from clinically diagnosed cases of CTF. Significant differences were noted in the number of convalescent-phase sera that reacted with each virus strain and in the number of seroconversions observed with each test virus strain. Convalescent phase sera that reacted with multiple virus strains often varied significantly in antibody titre from one virus strain to another. This indicates that, in some instances, antibody was probably produced in response to infection by different antigenic variants of CTF virus.

Antigenic relationships among Turlock serogroup Bunyaviruses as determined by neutralization tests.

Antigenic relationships between the five recognized Turlock serogroup viruses (family Bunyaviridae, genus Bunyavirus) were determined by serum dilution-plaque reduction neutralization tests. Results indicated that Turlock , Umbre , M' Poko and Lednice viruses are distinct from each other and that Yaba -1 virus is a subtype of M' Poko virus.

Evaluation of the solid-phase radioimmunoassay for diagnosis of St. Louis encephalitis infection in humans.

Since the use of highly purified viral proteins in the solid-phase radioimmunoassay (SPRIA) procedure is not practical for routine diagnostic serology, the procedure was adapted for use with the crude antigens now commonly used to diagnose St. Louis encephalitis (SLE) virus infections. SLE and various other alpha- and flavivirus antigens were tested by both the SPRIA procedure and conventional serological methods. Standards were established for use of the crude antigens in the SPRIA procedure. Reproducibility of the procedure was similar to that of conventional tests. The SPRIA procedure specifically differentiated SLE from clinically similar alphaviruses, but did not differentiate SLE from related flaviviruses very well. SPRIA diagnosis of SLE infections by the immunoglobulin G response in paired sera was good. Generally, the crude antigen SPRIA procedure was as sensitive as the conventional serological tests, but not as specific.

Use of glutaraldehyde-fixed goose erythrocytes in arbovirus serology.

Goose erythrocytes preserved with glutaraldehyde were compared with fresh cells in hemagglutination and hemagglutination-inhibition tests for arbovirus antigens and antibodies. The glutaraldehyde-fixed cells were as sensitive and specific as theresh erythrocytes and were stable at 4 degrees C for 6 months.

Production of antibody in induced granulomas.

A method of producing antibodies in artificially induced granulomas with various microbial antigens is examined.

Paper-strip blood-sampling technique for the detection of antibody to the plague organism Yersinia pestis.

The paper-strip blood-sampling technique was evaluated for efficacy in plague passive hemagglutination tests. It is valuable for widespread serological surveys.