Assessment of bleb morphologic features and postoperative outcomes after Ex-PRESS drainage device implantation versus trabeculectomy

PURPOSE

To investigate bleb morphologic features and postoperative outcomes after Ex-PRESS drainage device (Alcon Laboratories) implantation versus trabeculectomy.

DESIGN

Retrospective, consecutive case-control series.

METHODS

Information was collected from the charts of 35 consecutive Ex-PRESS procedures and 35 consecutive trabeculectomy procedures with at least 2 years of follow-up. Intraocular pressure (IOP), bleb morphologic features, reduction of dependence on medication, visual recovery, number of postoperative visits, and postoperative complication rates were compared between groups.

RESULTS

Average follow-up was 28 months (standard deviation, 3.23 months). Mean IOP measurements were similar after 6 months, then became slightly higher in the Ex-PRESS group at 1 year and at the final follow-up (P = .004 and P = .008, respectively). Final percent IOP lowering was similar between groups (P = .209). Unqualified success was achieved in 77.14% of Ex-PRESS and 74.29% of trabeculectomy procedures at last follow-up (P = 1.00). An additional 5.71% and 8.57% reached qualified success for Ex-PRESS and trabeculectomy surgeries, respectively (P = .99). Evaluation by the Moorfields Bleb Grading System revealed less vascularity and height but more diffuse area associated with the Ex-PRESS blebs, although these differences were absent at study completion. There were fewer cases of early postoperative hypotony and hyphema and quicker visual recovery in the Ex-PRESS group. The Ex-PRESS group required fewer postoperative visits compared with the trabeculectomy group (P < .000).

CONCLUSIONS

Success of Ex-PRESS surgery, as defined in our study, was similar to trabeculectomy. Final IOP measurements were slightly lower after trabeculectomy compared with Ex-PRESS. Differences in some postoperative outcomes faded with follow-up. There remains a need for long-term prospective studies comparing these 2 procedures.

Nosocomial transmission of hepatitis C virus within a British dialysis centre

Patients on renal replacement therapy are recognized as a group at increased risk of infection with hepatitis C virus (HCV). While the risk has been reduced by the use of erythropoietin for treatment of anaemia and the introduction of HCV screening of blood products and potential renal transplant donors, new cases of HCV are still being documented, with patients on hospital haemodialysis appearing to be particularly at risk. The exact mode of transmission of HCV within dialysis units is unclear, although there is evidence to support nosocomial transmission between patients. Third generation HCV antibody testing was performed on all dialysis patients when a new case of HCV was identified within our unit. Stored monthly serum samples were then examined retrospectively to determine when patients became HCV RNA and HCV antibody positive. Viral typing was carried out to identify the HCV strains responsible for transmission. Four new cases of HCV infection are described within a single dialysis shift. Viral typing identified two distinct strains of HCV as being responsible for these infections, both of which had previously been identified in dialysis patients within the unit known to have HCV infection. This information, taken in conjunction with knowledge of the location of each patient for dialysis, suggests two separate episodes of nosocomial transmission of HCV between haemodialysis patients. While evidence of nosocomial transmission of HCV is accumulating, with modern dialytic procedures evidence of transmission through the dialysis machine or equipment used for dialysis is lacking. This stresses the importance of strict applications of universal precautions as the key to prevention of further transmission of HCV infection. This information is obviously applicable not only to dialysis units but all units that may potentially come in contact with HCV patients.

Biochemical and physiological validation of a corticosteroid radioimmunoassay for plasma and fecal samples in oldfield mice (Peromyscus polionotus)

The measurement of fecal steroids provides an increasingly important noninvasive technique for assessing reproduction, environmental stress, and aggression in populations of captive and free-living animals. In this paper, we validated the corticosterone (CORT) 125I-radioimmunoassay (ICN Pharmaceuticals) for plasma and fecal samples in a small rodent species, the oldfield mouse (Peromyscus polionotus subgriseus). The biochemical validations indicated that the assays accurately measured CORT concentrations in the plasma and corticosteroid concentrations in the feces. Physiological validation demonstrated that: (1) blood samples collected within 3 min of disturbing an animal's cage represented "baseline" CORT concentrations, and (2) fecal corticosteroid concentrations collected over a 24-h period closely tracked plasma CORT concentrations approximately 4 h earlier. These results demonstrate that the plasma CORT and fecal corticosteroid assays are sensitive enough to detect biologically meaningful alterations in corticosteroid concentrations in oldfield mice.

The use of bonded-phase extraction columns for rapid sample preparation of benzodiazepines and metabolites from serum for HPLC analysis

A simple, rapid method for the determination of the benzodiazepines, diazepam and chlordiazepoxide, and their metabolites by high performance liquid chromatography (HPLC) has been developed. The procedure is applicable to the assay of other similar drugs in biological fluids. The method utilizes BondElut extraction columns to facilitate the extraction. BondElut columns selectively adsorb the benzodiazepines and metabolites from serum at a pH of 9.0. The compounds are eluted with 300 microliters of methanol which makes sample concentration rapid, if even necessary. Analysis is performed using isocratic reversed-phase chromatography, and quantitation is carried out by ultraviolet (UV) detection. Using this procedure, it is possible to determine drug and metabolite levels to as low as 25 ng/ml in 0.5 ml of serum.

Detection of antibodies against hepatitis C virus in saliva: a marker of viral replication

Hepatitis C surveillance has been restricted owing to the lack of a sensitive antibody assay for saliva. The aim of our study was to develop and evaluate a screening assay for hepatitis C antibody in saliva specimens. Serum/saliva pairs were collected from 115 hepatitis C-positive patients. A modified hepatitis C antibody assay for saliva was developed and linked to testing carried out in the diagnostic laboratory. Correlation between the presence of antibody in serum and in saliva was poor (100% vs 85%). However, of 98 patients who were saliva antibody positive, 96 (98%) were also serum hepatitis C RNA positive and two (2%) were serum hepatitis C RNA negative. Hence, the correlation between a positive salivary antibody test and the serum hepatitis C RNA status of intravenous drug users suggests that this test could be used as a surrogate marker for hepatitis C viraemia in epidemiological studies.

Predominance of HCV type 2a in saliva from intravenous drug users

Paired serum and saliva samples were collected simultaneously from 50 intravenous drug users with serologically proven hepatitis C virus infection. The oral health of the volunteers was also assessed. Hepatitis C virus RNA was detected by nested PCR, employing primers from the 5' noncoding region. Positive PCR products were sequenced using the Sequenase PCR Product Sequencing Kit (Amersham Life Sciences). HCV RNA was detected in 33 (66%) of the 50 serum samples. HCV RNA was detected in 19 (57.6%) of the corresponding 33 saliva samples. There was no correlation between oral health status or HIV seropositivity and the detection of HCV in saliva. However, subjects with HCV in their saliva were significantly more likely to complain of xerostomia (P < 0.05). Isolate genotypes were identified in paired serum and saliva of 15 intravenous drug users. HCV genotypes 1, 2, 3 and 6 were detected in both specimens. In seven cases, a differing HCV genotype was found in serum compared to the paired saliva specimen. The distributions of genotypes in serum and saliva were very different, with genotype 2a more common in saliva than serum (P < 0.005). These data suggest that in some cases the source of salivary HCV may not be serum transudation along the periodontal membrane or across damaged mucosa, and that an alternative local source, possibly the salivary glands themselves, should be considered.

The role of endothelin in the pathophysiology of glaucoma

IMPORTANCE OF THE FIELD

Glaucoma is the second leading cause of blindness worldwide. To date, treatment of glaucoma has focused on lowering intraocular pressure (IOP) though there are other mechanisms that might damage the optic nerve, leading to characteristic visual field loss. Endothelin, a potent vasoconstrictor, is believed to play a role in the pathogenesis of glaucomatous optic neuropathy.

AREAS COVERED IN THIS REVIEW

We review the evidence from the last 20 years exploring the action of endothelin in the eye, its association with the pathophysiology of glaucoma, as well as the potential therapeutic role of targeting the endothelin pathway to affect disease progression in glaucomatous eyes.

WHAT THE READER WILL GAIN

The goal of this paper is to inform readers about endothelin structure, actions, and role in ocular pathology, pharmacology, and potential areas of future research.

TAKE HOME MESSAGE

Overall, we believe that the body of evidence supports the following conclusions; i) endothelin is a potent vasoconstrictor that plays a role in ocular physiology, ii) endothelin may play a role in the pathophysiology of glaucoma and iii) modulation of the endothelin system with newly discovered potent antagonists holds promise in treating glaucoma through both pressure-dependent and pressure-independent pathways.

Viral kinetics can predict early response to alpha-interferon in chronic hepatitis C

AIMS/BACKGROUND

Response rates to alpha-interferon therapy for chronic hepatitis C are poor. An early indication of efficacy would reduce the need for prolonged therapy, leading to significant cost savings. It was established that a change in quantitative hepatitis C virus RNA (HCV-RNA) titre at 4 weeks could predict the outcome of alpha-interferon therapy in chronic hepatitis C.

METHODS

Serum HCV-RNA titres were quantified using branched chain DNA (bDNA) assay in 26 patients who responded to alpha-interferon (serum HCV-RNA negative after 12 weeks therapy) and 11 age and sex matched non-responders. Quantitative bDNA and qualitative RT-PCR assays for HCV-RNA were measured pretreatment and at 4 weeks. The change in quantitative HCV-RNA titre between pre-therapy and after 4 weeks was compared in the two groups.

RESULTS

Seventeen of the 37 patients had become RT-PCR negative at 4 weeks (early responders) and had an undetectable HCV-RNA titre on bDNA assay. Nine patients were RT-PCR positive at 4 weeks but negative by 12 weeks (delayed responders), and of these, 8 had an undetectable viral titre at 4 weeks on bDNA assay. The patient with a detectable HCV titre did become RT-PCR negative after 12 weeks, but subsequently became RT-PCR positive again at 24 weeks. All the non-responders had a detectable bDNA titre (> 0.2 Meq/ml) at 4 weeks.

CONCLUSIONS

Change in quantitative HCV-RNA titre measured by bDNA assay at 4 weeks predicts response to alpha interferon. If HCV-RNA remains detectable on bDNA assay at 4 weeks, no sustained response to treatment is found and alpha-interferon can be discontinued.