The effect of hyaluronic acid and phospholipid based lubricants on friction within a human cartilage damage model

The lubricating abilities of different formulations of high molecular weight hyaluronic acid (HA), dipalmitoyl phosphatidylcholine (DPCC) and mixtures of both HA and DPCC were assessed in an in vitro model. Levels of start-up friction were determined using an osteoarthritis (OA) damaged human cartilage model set within a specially designed friction rig. To examine the long term benefits of HA, the extent of penetration of HA into cartilage tissue was investigated using fluorescently labelled HA and confocal microscopy. It was found that in this model, all formulations of HA and the majority of DPCC lubricants reduced friction (HA 5 and 10 mg ml(-1), DPPC 200 mg ml(-1) reductions of 51.9%, 46.7% and 46.5% respectively), compared to a Ringers solution control. Lubrication was found not to be concentration dependent for HA formulations, but concentration was key for DPCC lubrication (100 mg ml(-1) reduced friction by only 15.9%). By combining HA and DPCC (HA/DPPC; 5 mg ml(-1)/100 mg ml(-1) and 10 mg ml(-1)/200 mg ml(-1)), a further improvement was noted (69.5% and 61.9%, respectively) as the mean levels of friction were reduced by up to a further 17% than the most effective individual formulation (HA 5 mg ml(-1)). Penetration of HA into bovine cartilage by up to 300 microm from the surface was observed over a 48 h period. It was observed that HA specifically targeted the chondrocytes as it was primarily found within the lacunae surrounding the cells.     

Antichlamydial antibodies in pelvic inflammatory disease

The role of Chlamydia trachomatis in pelvic inflammatory disease (PID) diagnosed without laparoscopy was assessed by measuring antichlamydial antibodies in the patient's serum and by comparing the results with those in patients with uncomplicated non-specific genital infection (NSGI) and gonorrhoea and in non-infected controls. A modified microimmunofluorescence test was used. Patients with severe PID had significantly more positive antichlamydial IgG and IgM results than did control subjects, patients with gonorrhoea, and patients with NSGI. Less severe PID was associated with significantly raised levels of antichlamydial IgG antibodies compared with NSGI and controls and with raised levels of IgM antibodies compared with controls. Two patients with PID had lower genital tract gonorrhoea, one of whom had raised antichlamydial antibody levels. These findings may indicate a mixed infection and therapy should be reviewed in such patients. A serological diagnosis of chlamydial infection is relatively easy and cheap and enables a rapid diagnosis of chlamydial infection to be made.     

Sequential antibody changes following ulcerative herpetic keratitis.

Blood and tear levels of immunoglobulins against herpes simplex virus (HSV) were examined in 28 patients with dendritic keratitis over a period of 28 days. By means of an indirect micro-immunofluorescent technique blood and tear HSV IgG were detected, but neither circulating HSV IgM nor local HSV IgA were found. Over a four-week interval non-diagnostic fluctuations of HSV IgG occurred in most patients, though seven (25%) developed a rising blood IgG titre. Tear IgG appeared to be an exudate from blood. HSV was isolated from 68% of corneal swabbings and 11% of conjunctival swabbings. This study provides guidelines for laboratory testing in recurrent herpetic keratitis.     

Comparison of two immunofluorescence tests for detecting antibodies to C. trachomatis

Two immunofluorescence tests were compared for detecting antibodies to chlamydiae. The inclusion antigen test was more sensitive, detecting antibodies in more sera and at higher titres. The micro-IF test was more specific, differentiating between antibodies to C. trachomatis and those to C.IOL 207. Antibodies to this non-genital chlamydial type accounted for half the positive results. These antibodies can cause the prevalence of C. trachomatis infections to be over estimated when genus-specific serology tests are used.Corresponding author.