Temporal relation of antigenaemia and loss of antibodies to core antigens to development of clinical disease in HIV infection.

A total of 276 sequential serum samples from 34 men with antibodies to the human immunodeficiency virus (HIV) followed up for two to seven years were analysed for HIV antigen and antibodies to the viral core and envelope proteins. Results were correlated with clinical outcome and CD4 T lymphocyte count. Both antigenaemia and the disappearance of antibodies to the core protein were associated with development of the acquired immune deficiency syndrome (AIDS) or AIDS related complex and depletion of CD4 cells. Thus AIDS or AIDS related complex developed in eight out of 16 patients with antigenaemia compared with one out of 18 patients without antigenaemia. Low counts of CD4 cells (less than 0.5 X 10(9)/l) were found in 14 of the 16 patients with antigenaemia and five of the 18 without antigenaemia. Nine patients seroconverted to HIV during the study; two of these developed antigenaemia 14 and 16 months after the estimated time of seroconversion. These results show that the late stages of HIV infection are characterised by increased production of antigen and a decrease in antibodies directed against the core protein. Antigenaemia indicates a poor prognosis; and as the antigen test is simple to do and interpret, it may therefore be useful for selecting patients for antiviral treatment.     

Development of resistance to zidovudine in HIV strains isolated from CD4+ lymphocytes and plasma during therapy.

An assay based on production of HIV antigen in cultures of CD4+ lymphocytes infected 'in vitro' with cell-free virus was established. Using this assay it was possible to isolate, propagate and reliably determine the zidovudine susceptibility of HIV isolates from all patients despite differences in cellular tropism and syncytium inducing capacity. Using this assay, differences in zidovudine susceptibility of 52 serial isolates obtained from 16 patients before and after initiation of therapy were examined. HIV with a 10- to 100-fold reduced susceptibility to zidovudine were isolated from 13 patients as early as 4 months after initiation of therapy. Number of months of zidovudine treatment was strongly associated with development of viral resistance, and high CD4 cell counts tended to be associated with lower rates of development of resistance. That patients can harbor mixtures of virus strains with different susceptibility to zidovudine was confirmed by the differences in susceptibility between isolates obtained simultaneously from CD4+ lymphocyte and plasma, and by the differences in susceptibility between virus strains isolated from clones of CD4+ lymphocytes.     

Hormone replacement therapy dissociates fat mass and bone mass, and tends to reduce weight gain in early postmenopausal women: a randomized controlled 5-year clinical trial of the Danish Osteoporosis Prevention Study.

The aim of this study was to study the influence of hormone replacement therapy (HRT) on weight changes, body composition, and bone mass in early postmenopausal women in a partly randomized comprehensive cohort study design. A total of 2016 women ages 45-58 years from 3 months to 2 years past last menstrual bleeding were included. One thousand were randomly assigned to HRT or no HRT in an open trial, whereas the others were allocated according to their preferences. All were followed for 5 years for body weight, bone mass, and body composition measurements. Body weight increased less over the 5 years in women randomized to HRT (1.94 +/- 4.86 kg) than in women randomized to no HRT (2.57 +/- 4.63, p = 0.046). A similar pattern was seen in the group receiving HRT or not by their own choice. The smaller weight gain in women on HRT was almost entirely caused by a lesser gain in fat. The main determinant of the weight gain was a decline in physical fitness. Women opting for HRT had a significantly lower body weight at inclusion than the other participants, but the results in the self-selected part of the study followed the pattern found in the randomized part. The change in fat mass was the strongest predictor of bone changes in untreated women, whereas the change in lean body mass was the strongest predictor when HRT was given. Body weight increases after the menopause. The gain in weight is related to a decrease in working capacity. HRT is associated with a smaller increase in fat mass after menopause. Fat gain protects against bone loss in untreated women but not in HRT-treated women. The data suggest that women's attitudes to HRT are more positive if they have low body weight, but there is no evidence that the conclusions in this study are skewed by selection bias.     

The Effect of Intensive Insulin Therapy on the Insulin-regulatable Glucose Transporter (GLUT4) Expression in Skeletal Muscle in Type 1 Diabetes

Studies in normal man and rodents have demonstrated that the expression of the dominant glucose transporter in skeletal muscle, GLUT4, is regulated by insulin at supraphysiological circulating levels. The present study was designed to determine whether intensified insulin replacement therapy for 24 h given to patients with Type 1 diabetes in poor metabolic control was associated with an adaptive regulation of GLUT4 mRNA and protein levels in vastus lateralis muscle. Nine Type 1 diabetic patients with a mean HbA_1c of 10.3% were included in the protocol. After intensified treatment with soluble insulin for 24 h the fasting plasma glucose concentration decreased from 20.8 ± 2.3 (SD) to 8.7 ± 2.3 mmol 1^?1 whereas the fasting serum insulin level increased from 0.06 ± 0.02 to 0.17 ± 0.09 nmol 1^?1 However, despite a 2.8-fold increase in serum insulin levels and more than a halving of the plasma glucose concentration for at least 15 h no significant alterations occurred in the amount of GLUT4 protein (0.138 ± 0.056, poor control vs 0.113 ± 0.026 arb. units, improved control, p = 0.16) or GLUT4 mRNA (96432 ± 44985, poor control vs 81395 ± 25461 arb. units, improved control, p = 0.54). These results suggest, that in spite of evidence that high insulin levels affect GLUT4 expression in muscle, changes in serum insulin within the physiological range do not play a major role in the short-term regulation of GLUT4 expression in Type 1 diabetic patients.     

Geographical and temporal conservation of antibody recognition of Plasmodium falciparum variant surface antigens

The slow acquisition of protection against Plasmodium falciparum malaria probably reflects the extensive diversity of important antigens. The variant surface antigens (VSA) that mediate parasite adhesion to a range of host molecules are regarded as important targets of acquired protective immunity, but their diversity makes them questionable vaccine candidates. We determined levels of VSA-specific immunoglobulin G (IgG) in human plasma collected at four geographically distant and epidemiologically distinct localities with specificity for VSA expressed by P. falciparum isolates from three African countries. Plasma levels of VSA-specific IgG recognizing individual parasite isolates depended on the transmission intensity at the site of plasma collection but were largely independent of the geographical origin of the parasites. The total repertoire of immunologically distinct VSA thus appears to be finite and geographically conserved, most likely due to functional constraints. Furthermore, plasma samples frequently had high IgG reactivity to VSA expressed by parasites isolated more than 10 years later, showing that the repertoire is also temporally stable. Parasites from patients with severe malaria expressed VSA (VSASM) that were better recognized by plasma IgG than VSA expressed by other parasites, but importantly, VSASM-type antigens also appeared to show substantial antigenic homogeneity. Our finding that the repertoire of immunologically distinct VSA in general, and in particular that of VSASM, is geographically and temporally conserved raises hopes for the feasibility of developing VSA-based vaccines specifically designed to accelerate naturally acquired immunity, thereby enhancing protection against severe and life-threatening P. falciparum malaria.     

Demonstration by immunoelectro-osmophoresis of precipitating antibodies to a purified rubella virus antigen.

The nonionic detergent Triton X-100 was used to extract antigens of rubella virus from infected tissue culture cells. Three virus-specific antigens were demonstrated by crossed immunoelectrophoresis by using a pool of human gamma globulin as antiserum. The most dominant of these antigens were purified by ion-exchange chromatography on diethylaminoethyl-cellulose. This antigen was of glucoprotein nature and had slow electrophoretic motility and low binding capacity to diethylaminoethyl-cellulose. Thus, it seems likely that the antigen is identical with the precipitating antigen of rubella virus designated b-antigen or tro-osmophoresis with precipiting antibody in sera obtained from patients recovering from acute postnatal rubella. The precipitin reaction that could be correlated to the hemaglutination-inhibition titers of the same sera appeared 12 days after onset of the disease and remained positive for several years.     

Quantitative immunoelectrophoretic analysis of human antibodies against herpes simplex virus antigens.

By use of crossed immunoelectrophoresis with intermediate gel, antidbody titers against six individual herpes simplex virus (HSV) glycoproteins and two nonglycosylated proteins were determined in 100 human sera. High antibody titers were found against two different HSV type-common glycoproteins designated Ag8 and Ag11 (containing glycosylated polypeptides D and B, respectively). The anti-Ag8 and -Ag11 titers correlated with HSV neutralizing antibody titers. Most of the serological cross-reactivity between HSV type 1 and type 2 was probably caused by antibodies to Ag8 and Ag11. Human antibodies against one HSV type 1-specific glycoprotein (Ag6, containing glycosylated polypeptide C) and two HSV type 2 glycoproteins (Ag4 and Ag9) were also demonstrated, and the titers correlated better with neutralizing antibody titers of the homologous than of the heterologous virus type. The data presented can be directly applied to the further development of diagnostic reagents.     

Computer-assisted prenatal aneuploidy screening for chromosome 13, 18, 21, X and Y based on multiplex ligation-dependent probe amplification (MLPA)

In routine prenatal diagnostics we used a commercial multiplex ligation-dependent probe amplification (MLPA) kit for aneuploidy screening for chromosomes 13, 18, 21, X and Y. We present the results of 1593 consecutive prenatal samples analysed and diagnosed prior to knowledge of the G-banding analysis during 8-month routine use of computer-assisted MLPA aneuploidy screening. In total, 27 aneuploidies were detected. There were no false positive results while two false negative results could be explained by a placental mosaicism and a partial monosomy, respectively. In total, 3.2% of the samples were inconclusive. We conclude that automatic computer assisted MLPA is a rapid, simple and reliable method for detection of aneuploidies in prenatal diagnostics.     

Double-blind, placebo-controlled food challenge with apple

The aim of the study was to develop and evaluate different methods of double-blind, placebo-controlled food challenge (DBPCFC) with apple. Three different DBPCFC models were evaluated: fresh apple juice, freshly grated apple, and freeze-dried apple powder. All challenges were performed outside the pollen season and took place from 1997 to 1999. The freeze-dried apple material was characterized by means of leukocyte histamine release (HR), skin prick test (SPT), and immunoblotting experiments. The study population consisted of birch pollen-allergic patients with a history of rhinitis in the birch-pollen season and positive specific IgE to birch. For comparison of the DBPCFC models, 65 patients with a positive open oral challenge with apple were selected. In the characterization of the freeze-dried apple material, 46 birch pollen-allergic patients were included. The IgE reactivity to apple was evaluated by measurement of specific IgE, HR, and SPT. Golden Delicious apples were used in all experiments. The results of this study showed that it was possible to perform DBPCFC with apple in birch pollen-allergic individuals. The model with freshly squeezed apple juice had a low sensitivity and displayed a high frequency of reactions to placebo, probably due to the ingredients used for blinding. The sensitivity of the models with freshly grated apple and freeze-dried apple powder was 0.74/0.60. An increase in sensitivity is desirable. The freeze-dried apple powder proved to be useful for SPT, HR, and oral challenges, but further investigation of the stability and the allergenic profile of the material is needed.