Successful treatment of disseminated cutaneous cytomegalic inclusion disease associated with Hodgkin's disease

Viral skin infections in the elderly: diagnosis and management

Over the past several years, there have been advances in the diagnosis and treatment of cutaneous viral diseases in elderly patients. Herpes zoster is caused by reactivation in adults of the varicella-zoster virus (VZV) that causes chickenpox in children. For many years, aciclovir was the gold standard of antiviral therapy for the treatment of herpes zoster. Famciclovir and valaciclovir are newer antivirals, which offer less frequent administration. Postherpetic neuralgia (PHN) refers to pain lasting 2 months or more after an acute attack of herpes zoster. The pain may be constant or intermittent. The treatment of established PHN may include topical anaesthetics, analgesics, tricyclic antidepressants and anticonvulsants, and nonpharmacological therapy may be used to complement such treatment. Therapeutic strategies to prevent PHN include the use of oral corticosteroids, nerve blocks, and treatment with standard antiviral therapy. The three most recently discovered human herpes viruses (HHV-6, HHV-7 and HHV-8), in common with the other members of the family, may cause a primary infection, establish latent infection in a specific set of cells in their host, and then reactivate if conditions of altered immunity develop. These viruses have been associated with an array of disorders, which are important for the clinician to recognise. Cytomegalovirus (CMV) is a member of the herpesvirus family that is very prevalent worldwide. More than 80% of primary infections and 20% of reactivation-producing symptoms occur in transplant populations. Treatment options include intravenous administration of ganciclovir, foscarnet or cidofovir. Herpes simplex virus (HSV) most commonly affects the genital and perioral regions. In the elderly, HSV infection is typically manifest at the vermilion border of the lip. The main concern of recurrent herpes labialis in the elderly is related to potential autoinoculation of the eye or genital area. Treatment with aciclovir, famciclovir or valaciclovir is indicated for these infections. Molluscum contagiosum is caused by a poxvirus, which produces cutaneous lesions that appear as small, firm, umbilicated papules. Immunocompromised patients often do not respond to the usual destructive therapies, and intravenous or topical cidofovir may be useful in these patients.

Separation methods for acyclovir and related antiviral compounds

Acyclovir (ACV) is an antiviral drug, which selectively inhibits replication of members of the herpes group of DNA viruses with low cell toxicity. Valaciclovir (VACV), a prodrug of ACV is usually preferred in the oral treatment of viral infections, mainly herpes simplex virus (HSV). Also other analogues such as ganciclovir and penciclovir are discussed here. The former acts against cytomegalovirus (CMV) in general and the latter against CMV retinitis. The action mechanism of these antiviral drugs is presented briefly here, mainly via phosphorylation and inhibition of the viral DNA polymerase. The therapeutic use and the pharmacokinetics are also outlined. The measurement of the concentration of acyclovir and related compounds in biological samples poses a particularly significant challenge because these drugs tend to be structurally similar to endogenous substances. The analysis requires the use of highly selective analytical techniques and chromatography methods are a first choice to determine drug content in pharmaceuticals and to measure them in body fluids. Chromatography can be considered the procedure of choice for the bio-analysis of this class of antiviral compounds, as this methodology is characterised by good specificity and accuracy and it is particularly useful when metabolites need to be monitored. Among chromatographic techniques, the reversed-phase (RP) HPLC is widely used for the analysis. C18 Silica columns from 7.5 to 30 cm in length are used, the separation is carried out mainly at room temperature and less than 10 min is sufficient for the analysis at 1.0-1.5 ml/min of flow-rate. The separation methods require an isocratic system, and various authors have proposed a variety of mobile phases. The detection requires absorbance or fluorescence measurements carried out at 250-254 nm and at lambdaex=260-285 nm, lambdaem=375-380 nm, respectively. The detection limit is about 0.3-10 ng/ml but the most important aspect is related to the sample treatment, mainly when body fluids are under examination. The plasma samples obtained from human blood are pre-treated with an acid or acetonitrile deproteinization and the supernatant after centrifugation is successively extracted before RP-HPLC injection. Capillary Electrophoresis methods are also discussed. This new analytical approach might be the expected evolution, in fact the analyses are improved with regard to time and performance, in particular coated capillary as well as addition of stabilisers have been employed. The time of analysis is shortened arriving at less than half a minute. Furthermore by using an electrochemical detection, and having a calibration linearity in the range of 0.2-20.0 ng/ml, the detection limit is 0.15 microg/ml. The measurements of acyclovir and penciclovir have been presented but in the future other related drugs will probably be available using CE methods.