Comparisons of human, rat and mouse erythropoietins by isoelectric focusing: differences between serum and urinary erythropoietins

Isoelectric focusing (IEF) in the pH range 2.5-5.0 has been used to compare the immunoreactive (ir) erythropoietin (Epo) in paired samples of serum and urine from three patients, two with idiopathic aplastic anaemia and one with paroxysmal nocturnal haemoglobinuria and also from three anaemic rats. Serum samples only were also examined from two further patients with aplastic anaemia and from three mice, made anaemic (like the rats) by irradiation and phenylhydrazine treatment. Most of the ir-Epo recovered after IEF was found in the pH range 2.5-3.9. For the sera, the proportion of more acidic ir-Epo with pI less than 3.0 recovered after IEF increased from human to rat to mouse. Human sera contained a greater proportion of ir-Epo with pI greater than 3.4 than rat or mouse sera. For the urines, the distribution of ir-Epo by IEF was similar between human and rat. For both species, the proportion of ir-Epo with pI less than 3.0 recovered after IEF was greater in urine than in the paired serum samples. The Second International Reference Preparation of Human Urinary Epo differed from the Epo in unextracted human urine in that there was a lower proportion of ir-Epo with pI less than 3.0. The differences observed between serum and urinary Epo are of particular interest because only the urinary form of native human Epo has ever been purified, and because this was used to compare native with rDNA-derived Epo.     

The biochemical and clinical consequences of 2'-deoxycoformycin in refractory lymphoproliferative malignancy

A deficiency of adenosine deaminase, an enzyme important in purine nucleoside catabolism, is associated with a severe combined immunodeficiency disease in children. Inhibition of this enzyme in vitro and in vivo results in an impairment in lymphoblast proliferation. We have investigated the pharmacologic inhibition of this enzyme by 2'-deoxycoformycin in 15 patients with hematologic malignancies. Biochemical consequences of the administration of this agent were closely monitored in erythrocytes, nucleated peripheral blood and bone marrow cells, serum, and urine. A marked rise in erythrocyte dATP was accompanied by a depletion of ATP in those patients exhibiting toxicity. Most patients excreted large amounts of deoxyadenosine but not adenosine in the urine. Serum deoxyadenosine rose in patients demonstrating a marked decrease in cell mass. The biochemical disturbances and clinical toxicity, including hepatic, renal, and conjunctival abnormalities, were usually reversible. Central nervous system toxicity, which potentially was the most serious consequence, was associated with high erythrocyte dATP/ATP ratios and high levels of cerebrospinal fluid deoxyadenosine. In patients with lymphoma and leukemia, objective responses were observed but were short- lived. Patients with chronic lymphocytic leukemia receiving weekly low doses of the drug demonstrated minimal toxicity and some efficacy. The chemotherapeutic potential o 2'-deoxycoformycin, as either a single agent or in combination with Ara-A, merits further exploration.     

Relationship between deep vein thrombosis and pulmonary embolism following THA and TKA

Patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) are at risk for venous thromboembolisms, including deep vein thrombosis and pulmonary embolism. Most deep vein thromboses are asymptomatic, but they can lead to long-term morbidity to the same extent as symptomatic events. The risk of complications of venous thromboembolisms depends on the location of thrombi; potential long-term complications include recurrent venous thromboembolism, postthrombotic syndrome, and chronic thromboembolic pulmonary hypertension. Risk of recurrence persists for several years after the initial event. Approximately 20% of recurrent events are pulmonary embolisms, and approximately half of those are fatal. The causal relationship between deep vein thrombosis and pulmonary embolism remains controversial. Some consider them distinct clinical entities, while others have found asymptomatic distal deep vein thrombosis to be associated with elevated risk of developing pulmonary embolism. Unique coagulation factors may be associated with orthopedic surgery patients that differentiate them from patients undergoing other types of surgery. Symptomatic and asymptomatic deep vein thrombosis can lead to the development of recurrent venous thromboembolism, pulmonary embolism, postthrombotic syndrome, and chronic thromboembolic pulmonary hypertension, all of which are associated with reduced quality of life and increased health care expenditures. Thromboprophylaxis is therefore important in patients undergoing THA or TKA. However, traditional anticoagulants are not ideal, particularly for long-term use. Orthopedic surgeons should be aware of the causes and potential sequelae of venous thromboembolism and of the new thromboprophylactic agents that can help prevent it.     

Multiple Influenza A (H3N2) Mutations Conferring Resistance to Neuraminidase Inhibitors in a Bone Marrow Transplant Recipient

Immunocompromised patients are predisposed to infections caused by influenza virus. Influenza virus may produce considerable morbidity, including protracted illness and prolonged viral shedding in these patients, thus prompting higher doses and prolonged courses of antiviral therapy. This approach may promote the emergence of resistant strains. Characterization of neuraminidase (NA) inhibitor (NAI)-resistant strains of influenza A virus is essential for documenting causes of resistance. In this study, using quantitative real-time PCR along with conventional Sanger sequencing, we identified an NAI-resistant strain of influenza A (H3N2) virus in an immunocompromised patient. In-depth analysis by deep gene sequencing revealed that various known markers of antiviral resistance, including transient R292K and Q136K substitutions and a sustained E119K (N2 numbering) substitution in the NA protein emerged during prolonged antiviral therapy. In addition, a combination of a 4-amino-acid deletion at residues 245 to 248 (Δ245-248) accompanied by the E119V substitution occurred, causing resistance to or reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir). Resistant variants within a pool of viral quasispecies arose during combined antiviral treatment. More research is needed to understand the interplay of drug resistance mutations, viral fitness, and transmission.     

The prevalence of pain at pressure areas and pressure ulcers in hospitalised patients

Background

Patients with pressure ulcers (PUs) report that pain is their most distressing symptom, but there are few PU pain prevalence studies. We sought to estimate the prevalence of unattributed pressure area related pain (UPAR pain) which was defined as pain, soreness or discomfort reported by patients, on an “at risk” or PU skin site, reported at a patient level.

Methods

We undertook pain prevalence surveys in 2 large UK teaching hospital NHS Trusts (6 hospitals) and a district general hospital NHS Trust (3 hospitals) during their routine annual PU prevalence audits. The hospitals provide secondary and tertiary care beds in acute and elective surgery, trauma and orthopaedics, burns, medicine, elderly medicine, oncology and rehabilitation. Anonymised individual patient data were recorded by the ward nurse and PU prevalence team. The analysis of this prevalence survey included data summaries; no inferential statistical testing was planned or undertaken. Percentages were calculated using the total number of patients from the relevant population as the denominator (i.e. including all patients with missing data for that variable).

Results

A total of 3,397 patients in 9 acute hospitals were included in routine PU prevalence audits and, of these, 2010 (59.2%) patients participated in the pain prevalence study. UPAR pain prevalence was 16.3% (327/2010). 1769 patients had no PUs and of these 223 patients reported UPAR pain, a prevalence of 12.6%. Of the 241 people with pressure ulcers, 104 patients reported pain, a UPAR pain prevalence of 43.2% (104/241).

Conclusion

One in six people in acute hospitals experience UPAR pain on ‘at risk’ or PU skin sites; one in every 8 people without PUs and, more than 2 out of every five people with PUs. The results provide a clear indication that all patients should be asked if they have pain at pressure areas even when they do not have a PU.