Biomedical subjects

R Njemini

Publications and source records attributed to R Njemini.

5 recordsLinked to original sources

PubMed2006

The effect of aging and inflammation on heat shock protein 27 in human monocytes and lymphocytes.

Heat shock proteins (Hsp) are highly conserved proteins and their synthesis is ubiquitous in virtually every species in which they have been sought. In the present study we have investigated the effect of age and inflammation on the induction of Hsp27 in human peripheral blood mononuclear cells, using flow cytometry. Sixty-six healthy control subjects or patients suffering from inflammation participated in the study. In both heat shocked (HS) and non-HS conditions, the percentage of Hsp27 producing lymphocytes as well as the intensity of Hsp27 in lymphocytes and monocytes were negatively influenced by age. The basal levels and also the levels of Hsp27 production after HS were higher for monocytes compared to lymphocytes. In addition, we found that HS resulted in a small but significant increase in the levels of Hsp27 in lymphocytes whereas a significant decrease in Hsp27 was noticed for monocytes. In conclusion, results presented herein provide evidence in support of an age-related decrease in the level of Hsp27, which disappeared in the presence of inflammation. Several relationships between the circulating levels of CRP, IL-6 and TNF-alpha with the various Hsp27 determinations were observed, indicating that cytokines are able to influence the production of Hsp27.

Acute Disease↗

PubMed2004

Inflammatory status as an important determinant of heat shock protein 70 serum concentrations during aging.

Heat shock proteins (Hsp) form a large family of proteins that are ubiquitously present in all organisms. In the absence of destabilising stimuli, Hsp are expressed at low levels, but their expression can be highly induced by various noxious conditions such as heat, oxygen stress and infection. Hsp have been reported to interfere with inflammatory processes and their induction is well known to decrease with aging. In the present study we have investigated Hsp 70 serum concentrations using an optimised ELISA in elderly patients, recruited from a geriatric University Hospital ward. Our results portray positive correlations between the serum levels of Hsp 70 and various markers of inflammation (monocyte count, serum concentration of TNF-alpha, plasma concentrations of C-reactive protein, and fibrinogen), explaining the difference in Hsp 70 serum concentrations in these subjects with various degrees of inflammation. We conclude that Hsp 70 is involved in inflammatory diseases and that the serum level of Hsp 70 is directly linked to the inflammatory status of the subject. However, the nature of this relationship remains to be elucidated.

Aged↗

PubMed2003

Elevated serum heat-shock protein 70 levels in patients with acute infection: use of an optimized enzyme-linked immunosorbent assay.

Heat-shock proteins (Hsps) are highly conserved throughout evolution and evoke great interest both in basic biology and in medicine. They are expressed in small quantities under normal conditions, and their expression can be strongly induced by several stressors. Although their action is basically intracellular, it is now obvious that these proteins can be released into the extracellular environment from viable cells. In this study, the human Hsp 70 serum concentrations were determined using an optimized, cost-effective enzyme-linked immunosorbent assay (ELISA). The average intra-assay variation was 6%, whereas the average interassay variation was 9%. The sensitivity of the assay was 10 ng/ml, and spiking experiments showed recoveries between 101 and 109%. As an application of the technique, we have investigated the serum levels of human Hsp 70 in patients with infection and in healthy subjects. Our data show significantly higher levels of Hsp 70 (P = 0.003) in patients compared to control subjects. Positive correlations were noticed between the serum levels of Hsp 70 and various markers of inflammation (IL-6; r = 0.579, P = 0.009, TNF-alpha; r = 0.552, P = 0.012, IL-10; r = 0.361, P = 0.002). We conclude that Hsp 70 is involved in inflammation of infectious origin. The interindividual variation in the serum concentration of Hsp 70 precludes the use of serum Hsp 70 levels to distinguish patients from healthy subjects.

Acute Disease↗

PubMed2002

Age-related decrease in the inducibility of heat-shock protein 70 in human peripheral blood mononuclear cells.

We have investigated the effect of age and of the presence of proinflammatory cytokines on Hsp 70 production in human peripheral blood mononuclear cells, using flow cytometry. Twenty-seven women and 23 men, all apparently healthy, participated in the study. At 37 degrees C, the percentage of Hsp 70-producing monocytes and lymphocytes, as well as the level of Hsp 70 in monocytes, were negatively influenced by age. After exposure of the cells to 42 degrees C, the increase of Hsp 70 production was more pronounced in monocytes than in lymphocytes; both the intensity of Hsp 70 production and the percentage of Hsp 70-producing cells were negatively influenced by the age of the subjects, as well for monocytes as for lymphocytes. There was a negative correlation between the intensity of Hsp 70 production by monocytes exposed to 42 degrees C and the serum levels of tumor necrosis factor-alpha and interleukin-6. In conclusion, in human monocytes and lymphocytes, heat-induced Hsp 70 production is reduced with increasing age and is negatively influenced in monocytes by proinflammatory cytokines.

Adult↗

PubMed2002

The prevalence of autoantibodies in an elderly sub-Saharan African population.

In the present prospective, census-based study we have investigated the prevalence of organ-specific and non-organ-specific autoantibodies (AAb) in 152 unselected Cameroonians aged 60 years and older living in the community. AAb were detected in 49% of the participants. Non-organ-specific AAb (47%) predominated over organ-specific AAb (7%). Anti-TPO, anti-Tm, anti-Tg and anti-PC AAb were completely absent. RF was the most frequent AAb, being found in 57 (38%) cases. The prevalences of anti-SMA and RF were significantly higher in women than in men (respectively, P=0.023 and P=0.016). Higher serum concentrations of gammaglobulins were accompanied by a higher prevalence of RF (P < 0.0001) and a lower prevalence of ANA (P=0.036). The overall prevalence of AAb was higher in the filaria-infected (60%) compared to the non-infected (42%) participants (P=0.046). There was no significant influence of the vitamin D status, number of pregnancies, physical activity or medication use on the prevalence of AAb. In this study a heterogeneous pattern for the presence of the various AAb was found. Some AAb, which are commonly encountered in other studies on elderly subjects, were completely absent in this population. This diversified pattern of AAb prevalence therefore argues in favour of exogenous influences in the occurrence of AAb in elderly populations.

Aged↗