Life threatening hyperkalaemia with diarrhoea during ACE inhibition

A 67 year old woman developed acute renal failure with serum potassium 9.4 mmol/l requiring emergency dialysis after seven days of diarrhoea while taking an ACE inhibitor for vascular disease. Review of the literature, the British National Formulary, and the patient information leaflets for each of the 11 ACE inhibitors currently marketed in the UK suggests that this potentially life threatening complication of ACE inhibition is not yet widely recognised.

Filamin A mutations cause periventricular heterotopia with Ehlers-Danlos syndrome

OBJECTIVE

To define the clinical, radiologic, and genetic features of periventricular heterotopia (PH) with Ehlers-Danlos syndrome (EDS).

METHODS

Exonic sequencing and single stranded conformational polymorphism (SSCP) analysis was performed on affected individuals. Linkage analysis using microsatellite markers on the X-chromosome was performed on a single pedigree. Western blotting evaluated for loss of filamin A (FLNA) protein and Southern blotting assessed for any potential chromosome rearrangement in this region.

RESULTS

The authors report two familial cases and nine additional sporadic cases of the EDS-variant form of PH, which is characterized by nodular brain heterotopia, joint hypermobility, and development of aortic dilatation in early adulthood. MRI typically demonstrated bilateral nodular PH, indistinguishable from PH due to FLNA mutations. Exonic sequencing or SSCP analyses of FLNA revealed a 2762 delG single base pair deletion in one affected female. Another affected female harbored a C116 single point mutation, resulting in an A39G change. A third affected female had a 4147 delG single base pair deletion. One pedigree with no detectable exonic mutation demonstrated positive linkage to the FLNA locus Xq28, an affected individual in this family also had no detectable FLNA protein, but no chromosomal rearrangement was detected.

CONCLUSION

These results suggest that the Ehlers-Danlos variant of periventricular heterotopia (PH), in part, represents an overlapping syndrome with X-linked dominant PH due to filamin A mutations.

Numerical solutions to a kinetic model for the plasma-sheath problem with charge exchange collisions of ions

A kinetic model of the plasma-sheath problem is presented that includes the effects of charge-exchange collisions of the ion. The collisions are modeled as a sink for accelerated ions and as a source of cold ions. Solutions are obtained by numerical integration of Poisson's equation from a point near the plasma midplane to the wall. In the quasineutral region, these solutions agree with earlier analytic work. As the mean free path is decreased, the current density at the wall decreases and the potential profile in the quasineutral region shows a smooth transition from a parabolic profile to a nearly cubic profile determined by the ion mobility. An approximate expression is found for the ion flux to the wall in the collisional limit.

Diarrhoea, vomiting and ACE inhibitors:--an important cause of acute renal failure

The occurrence of severe acute renal failure in 3 patients who developed diarrhoea while taking angiotensin converting enzyme (ACE) inhibitors led us to undertake a retrospective cohort survey to determine the frequency with which diarrhoea and vomiting are associated with acute renal failure in patients taking this class of drug. Serum creatinine was measured as part of the diagnostic workup of 2398 consecutive admissions to an acute medical receiving unit in a district general hospital. Outcome measures were the presence of diarrhoea and/or vomiting, and whether taking an ACE inhibitor, NSAID or diuretic at the time of admission, also previous, initial and follow up serum creatinine concentrations. Peak serum creatinine in the 3 cases was 1159, 989 and 765 micromol/l. None of the 3 required dialysis and all recovered renal function completely after receiving large volumes of intravenous fluid. In the cohort study, 89 of 2398(3.7%) admissions had serum creatinine >/=200 micromol/l. Nine were regular dialysis patients. Of the remaining patients, 30 (37.5%) were taking an ACE inhibitor. Six of 30 (20%) gave a history of diarrhoea and/or vomiting. Median creatinine concentration in this group was 135 (range 111-209) micromol/l before admission, 292 (216-724) micromol/l when first seen in hospital, and 134 (94-219) micromol/l following the withdrawal of drug therapy and fluid replacement. In conclusion, volume depletion causing acute renal failure in patients taking ACE inhibitors is not uncommon. Such patients and their general practitioners should be aware that reversible renal impairment may occur during intercurrent illnesses, particularly if characterised by diarrhoea and/or vomiting.

High incidence of renal failure requiring short-term dialysis: a prospective observational study

BACKGROUND

Previous estimates of incidence of acute renal failure (ARF) requiring renal replacement therapy have varied from 18 to 75 patients per million per year, but have been beset by problems of definition.

AIM

To investigate whether the '90-day rule' provides a more reliable, reproducible and robust estimate of the need for short-term dialysis.

SETTING

District general hospital serving a population of 147 000.

DESIGN

Prospective observational study.

METHODS

Patients who received renal replacement therapy in Dumfries and Galloway between 01/01/94 and 31/12/2000 were divided into two groups: long-term dialysis (> or =90 days) and short-term dialysis (<90 days).

RESULTS

Of 302 patients, 193 received short-term dialysis, giving an incidence for short-term dialysis of 187 patient episodes per million per year (95%CI 170-203). Use of a more conventional definition for ARF (including all ARF and acute-on-chronic renal failure, but excluding patients with chronic renal failure who present acutely) produced a similar estimate at 176 patients per million per year (95%CI 160-193).

DISCUSSION

The 90-day rule estimated the incidence of short-term dialysis/ARF at nearly twice the incidence of chronic renal failure requiring dialysis, and more than twice the most recent estimate of the incidence of ARF in the UK. The main attraction of the 90-day rule is its simplicity. If the high level of short-term dialysis/ARF found in our study is confirmed by other centres, there are significant resource implications for the provision of renal care.

The use of snowboard boot bindings in a hip disarticulation prosthesis

This report describes a new technique for fastening a hip disarticulation socket. It was developed at the request of the patient who needed to fasten his prosthesis using only one hand, because of a left upper limb disability. Snowboard boot bindings were secured to the socket of the prosthesis and allowed it to be securely fastened and released using his dominant hand only. The design of the bindings permitted a high closing force with minimum one-handed effort by the user.

A randomized controlled trial of exercise to improve mobility and function after elective knee arthroplasty. Feasibility, results and methodological difficulties

OBJECTIVE

To assess the feasibility of comparing two types of exercise regime aiming to improve mobility and function following knee arthroplasty.

DESIGN

A single-blind randomized controlled trial.

SUBJECTS

Patients with primary, unilateral knee osteoarthritis undergoing elective knee joint replacement.

INTERVENTION

Home-based traditional exercise group (TEG) or home-based functional exercise group (FEG) following discharge from hospital.

OUTCOME MEASURES

These included goniometry; a knee-specific pain score, leg extensor power and a walking test. Patients were followed up at three, six and 12 months after surgery.

RESULTS

Forty-seven patients met the study criteria, 24 were randomized to the TEG and 23 to the FEG. There were marked improvements in mobility, leg extensor power and pain in the year after surgery (MANOVA p < 0.001). There were no statistically significant differences between the two exercise groups. Knee flexion decreased during the follow-up period and had not recovered by 12 months. Retention of patients was a problem, with nearly 50% lost to follow-up at 12 months. These patients were assessed as having low motivation during inpatient rehabilitation (p < 0.05).

CONCLUSIONS

There were trends in favour of the FEG that were of clinical relevance. A definitive study would need a sample size of at least 100 patients in each arm. It is essential to develop strategies to combat loss to follow-up.

The impact of relocation on elderly patients with mental illness

Twenty-three elderly patients with long-term mental illness were relocated from a large tertiary mental health facility to two extended care units (ECUs) in their district of origin. The patients were assessed on measures of functioning, aggression and agitation at 6 weeks pre-relocation, and again at 6 weeks and 6 months post-relocation. The impact of relocation on the group proved to be less dramatic than findings reported in the literature. The adverse affects of relocation were likely to have been offset by the preparation and planning undertaken prior to relocation, and the support provided to staff and patients in the period following relocation. The findings have implications for nursing staff involved in the relocation of people with mental illness between wards within a hospital or from one hospital to another.

Feline Pit2 functions as a receptor for subgroup B feline leukemia viruses

Different subgroups of feline leukemia virus (FeLV) use different host cell receptors for entry. Subgroup A FeLV (FeLV-A) is the virus that is transmitted from cat to cat, suggesting that cells expressing the FeLV-A receptor are important targets at the earliest stages of infection. FeLV-B evolves from FeLV-A in the infected cat through acquisition of cellular sequences that are related to the FeLV envelope gene. FeLV-Bs have been shown to infect cells using the Pit1 receptor, and some variants can infect cells at a lower efficiency using Pit2. Because these observations were made using receptor proteins of human or rodent origin, the role that Pit1 and Pit2 may play in FeLV-B replication in the cat is unclear. In this study, the feline Pit receptors were cloned and tested for their ability to act as receptors for different FeLV-Bs. Some FeLV-Bs infected cells expressing feline Pit2 and feline Pit1 with equal high efficiency. Variable region A (VRA) in the putative receptor-binding domain (RBD) was a critical determinant for both feline Pit1 and feline Pit2 binding, although other domains in the RBD appear to influence how efficiently the FeLV-B surface unit can bind to feline Pit2 and promote entry via this receptor. An arginine residue at position 73 in VRA was found to be important for envelope binding to feline Pit2 but not feline Pit1. Interestingly, this arginine is not found in endogenous FeLV sequences or in recombinant viruses recovered from feline cells infected with FeLV-A. Thus, while FeLV-Bs that are able to use feline Pit2 can evolve by recombination with endogenous sequences, a subsequent point mutation during reverse transcription may be needed to generate a virus that can efficiently enter the cells using the feline Pit2 as its receptor. These studies suggest that cells expressing the feline Pit2 protein are likely to be targets for FeLV-B infection in the cat.

Haemodialysis in a rural area: a demanding form of treatment

OBJECTIVE

To determine distances travelled and time spent waiting for transport among hospital haemodialysis patients living in a rural area.

DESIGN

Cross sectional survey comparing the subregional dialysis unit in south west Scotland with 12 of the other 13 Scottish Adult Renal Units.

SUBJECTS

Forty three Dumfries and Galloway patients and 935 other Scottish patients receiving hospital haemodialysis in November 1999.

RESULTS

At the time of the survey 8/43 (19%) Dumfries patients travelled in excess of 100 miles per dialysis day (15,000 miles per year) solely for the purpose of dialysis, compared to 20/935 (2%) elsewhere in Scotland (p < 0.001). Twenty seven (63%) Dumfries and 594 (64%) patients in other Scottish Units relied on hospital car, Patient Transport Service bus or ambulance for the journey home after treatment. Dumfries patients who travelled by Patient Transport Service or hospital ambulance had to wait twice as long before they left the renal unit as patients using a dedicated hospital car or private car.

CONCLUSION

Haemodialysis in a rural area has every reason to be considered a demanding form of treatment. Greater promotion of home based treatment would improve the quality of life for many of these patients, while dedicated hospital cars would reduce 'car to needle time' for those who remain on hospital haemodialysis.

Antibodies to capsular polysaccharides of group B Streptococcus in pregnant Canadian women: relationship to colonization status and infection in the neonate

In a cohort study of 1207 pregnant women in Alberta, Canada, the serotype distributions of vaginal-rectal group B Streptococcus (GBS) isolates were compared with all isolates from neonates with invasive GBS disease identified by population-based surveillance. Serum concentrations of Ia, Ib, II, III, and V capsular polysaccharide (CPS)-specific IgG also were determined, according to serotype of the vaginal-rectal colonizing GBS strain. GBS colonization was detected in 19.5% (235 of 1207) of women. Serotype III accounted for 20.6% (48 of 233) of colonizing strains available for typing but for 37% (27 of 73) of invasive isolates from neonates (P<.01). Maternal colonization with type III was least likely to be associated with moderate concentrations of III CPS-specific IgG. Serotype III GBS is more invasive than other serotypes in this population; this may be due, at least in part, to poor maternal type III CPS-specific antibody response.

IL-12 suppression during experimental endotoxin tolerance: dendritic cell loss and macrophage hyporesponsiveness

Endotoxin tolerance, the transient, secondary down-regulation of a subset of endotoxin-driven responses after exposure to bacterial products, is thought to be an adaptive response providing protection from pathological hyperactivation of the innate immune system during bacterial infection. However, although protecting from the development of sepsis, endotoxin tolerance also can lead to fatal blunting of immunological responses to subsequent infections in survivors of septic shock. Despite considerable experimental effort aimed at characterizing the molecular mechanisms responsible for a variety of endotoxin tolerance-related phenomena, no consensus has been achieved yet. IL-12 is a macrophage- and dendritic cell (DC)-derived cytokine that plays a key role in pathological responses to endotoxin as well as in the induction of protective responses to pathogens. It recently has been shown that IL-12 production is suppressed in endotoxin tolerance, providing a likely partial mechanism for the increased risk of secondary infections in sepsis survivors. We examined the development of IL-12 suppression during endotoxin tolerance in mice. Decreased IL-12 production in vivo is clearly multifactorial, involving both loss of CD11c(high) DCs as well as alterations in the responsiveness of macrophages and remaining splenic DCs. We find no demonstrable mechanistic role for B or T lymphocytes, the soluble mediators IL-10, TNF-alpha, IFN-alphabeta, or nitric oxide, or the NF-kappaB family members p50, p52, or RelB.

The molecular basis of X-linked spondyloepiphyseal dysplasia tarda

The X-linked form of spondyloepiphyseal dysplasia tarda (SEDL), a radiologically distinct skeletal dysplasia affecting the vertebrae and epiphyses, is caused by mutations in the SEDL gene. To characterize the molecular basis for SEDL, we have identified the spectrum of SEDL mutations in 30 of 36 unrelated cases of X-linked SEDL ascertained from different ethnic populations. Twenty-one different disease-associated mutations now have been identified throughout the SEDL gene. These include nonsense mutations in exons 4 and 5, missense mutations in exons 4 and 6, small (2-7 bp) and large (>1 kb) deletions, insertions, and putative splicing errors, with one splicing error due to a complex deletion/insertion mutation. Eight different frameshift mutations lead to a premature termination of translation and account for >43% (13/30) of SEDL cases, with half of these (7/13) being due to dinucleotide deletions. Altogether, deletions account for 57% (17/30) of all known SEDL mutations. Four recurrent mutations (IVS3+5G-->A, 157-158delAT, 191-192delTG, and 271-275delCAAGA) account for 43% (13/30) of confirmed SEDL cases. The results of haplotype analyses and the diverse ethnic origins of patients support recurrent mutations. Two patients with large deletions of SEDL exons were found, one with childhood onset of painful complications, the other relatively free of additional symptoms. However, we could not establish a clear genotype/phenotype correlation and therefore conclude that the complete unaltered SEDL-gene product is essential for normal bone growth. Molecular diagnosis can now be offered for presymptomatic testing of this disorder. Appropriate lifestyle decisions and, eventually, perhaps, specific SEDL therapies may ameliorate the prognosis of premature osteoarthritis and the need for hip arthroplasty.

Regulation of hemangioblast development

The in vitro differentiation of embryonic stem (ES) cells provides a powerful approach for studying the earliest events involved in the commitment of the hematopoietic and endothelial lineages. Using this model system, we have identified a precursor with the potential to generate both primitive and definitive hematopoietic cells as well as cells with endothelial characteristics. The developmental potential of this precursor suggests that it represents the in vitro equivalent of the hemangioblast, a common stem cell for both lineages. ES cells deficient for the transcription factor scl/tal-1 are unable to generate hemangioblasts, while those deficient for Runx1 generate reduced numbers of these precursors. These findings indicate that both genes play pivotal roles at the earliest stages of hematopoietic and endothelial development. In addition, they highlight the strength of this model system in studying the function of genes in embryonic development.

Experimental observation of the trapped particle pinch effect

The trapped particle pinch effect (Ware's drift) has been observed in a non-neutral plasma of electrons in a modified Malmberg-Penning trap in which electrons are contained in the annular volume between concentric cylinders. A pulsed azimuthal electric field is applied by increasing the flux within a solenoid on the axis. Radial displacements of the electrons are observed which show that they remain on a surface enclosing constant axial flux. These displacements are independent of the azimuthal field and thus are consistent with Ware's drift and inconsistent with the guiding center drift alone.