Low-copy-number human transgene is recognized as an X inactivation center in mouse ES cells, but fails to induce cis-inactivation in chimeric mice

X chromosome inactivation is initiated from a segment of the mammalian X chromosome called the X inactivation center. Transgenes from this region of the murine X chromosome are providing the means to identify the DNA needed for cis inactivation in mice. We recently showed that chimeric mice carrying transgenes from the human X inactivation center (XIC) region also provide a functional assay for human XIC activity; approximately 6 copies of a 480-kb human transgene (ES-10) were sufficient to initiate random X inactivation in cells of male chimeric mice (Migeon et al., 1999, Genomics, 59, 113-121). Now, we report studies of another human transgene (ES-5), which contains less than 300 kb of the human XIC region on Xq13.2 including an intact XIST locus and which has inserted in one or two copies into mouse chromosome 6. The ES-5 transgene is recognized as an X inactivation center in mouse embryonic stem cells, but is not sufficient to induce random X inactivation in somatic cells of highly chimeric mice. Human transgenes in chimeric mice provide a means to uncouple the key steps in this complex pathway and facilitate the search for essential components of the human XIC region.

Randomised controlled trial of oral vitamin A supplementation in preterm infants to prevent chronic lung disease

BACKGROUND

Intramuscular supplementation with vitamin A in large doses may reduce the incidence of chronic lung disease.

AIM

To investigate whether oral supplementation with vitamin A would reduce the incidence of chronic lung disease in a group of extremely low birthweight infants.

METHODS

Infants with birth weight < 1000 g were randomised at birth to receive oral vitamin A supplementation (5000 IU/day) or placebo for 28 days. The primary outcome was oxygen dependency at 28 days of age or death.

RESULTS

A total of 154 infants were randomised; 77 received vitamin A (median birth weight (interquartile range) 806 (710-890) g), and 77 received placebo (median birth weight (interquartile range) 782 (662-880) g). Plasma vitamin A concentrations in the supplemented group were significantly higher at 24 hours of age but did not differ significantly at birth, 12 hours of age, 7 days, or 28 days of life. There were no significant differences in the proportion of infants who survived, required oxygen at 28 days, required oxygen at 36 weeks postmenstrual age, survived without chronic lung disease at 36 weeks, survived without significant retinopathy, or who survived without significant intraventricular haemorrhage.

CONCLUSIONS

Oral supplementation with 5000 IU vitamin A in extremely low birthweight infants does not significantly alter the incidence of chronic lung disease. However, this dose may have been inadequate to achieve optimal serum retinol concentrations.

Benchmarking can facilitate the sharing of information on outcomes of care

Recent restructuring in the national health service (NHS) aimed to effect cultural and organisation changes that would ensure fair and equal access for service users to effective and efficient services. Clinical governance has been introduced as a means of delivering quality improvement. One element of this is the use of benchmarking to assess current process and outcome and to use comparative information to inform about current and best practice. The use of the Therapy Outcome Measure (TOM) (Enderby and John 1997) was investigated as an indicator to benchmark the outcomes of treatment for different client-groups and compare patterns of outcomes from different speech and language therapy (SLT) services. The study recruited eight SLT trust sites and ran for eighteen months. The TOM data was analysed to note similarities and differences in cases entering treatment, in the direction of change resulting from treatment, and on completing treatment. Variation was found on these points between cases with different disorders and across the trusts. TOM data could be used to provide a benchmark for a disorder against which services could make comparisons. However, for benchmarking to succeed there is a need for support and commitment from every level of an organisation.

Evaluation of the role of RANK and OPG genes in Paget's disease of bone

Paget's disease of bone (PDB) is one of the most common bone disorders in the western world. PDB is characterized by focal areas of increased osteoclastic bone resorption and bone formation, which leads to the formation of poorly structured bone. These abnormalities of bone turnover and structure predispose affected individuals to various complications including bone pain, deformity, pathological fracture, and an increased risk of osteosarcoma. One of the main mechanisms of osteoclast formation and activation involves the receptor activator of nuclear factor -kappaB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) pathway, where binding of RANKL to RANK results in the differentiation of osteoclast precursors. OPG, on the other hand, acts as an inhibitor of osteoclastogenesis by serving as a decoy receptor for RANKL. Recently, mutations in the RANK gene have been shown to cause familial expansile osteolysis, a rare bone disorder showing great similarity to PDB. We performed mutation analysis in the RANK and OPG genes in 28 PDB patients to investigate whether mutations in these genes could be responsible for PDB. Our data suggest that RANK is not directly involved in PDB in our set of patients, as no mutations in the RANK coding region could be identified and allele frequencies of RANK polymorphisms did not differ in PDB patients as compared with the random population. Also, in the OPG gene, we could not detect PDB-causing mutations. However, of the several polymorphisms identified, one (400 + 4 C/T in intron 2), showed a statistically significant increased frequency for the C allele in PDB patients, suggesting that individuals harboring this allele may be more susceptible for developing PDB.

Infection control issues in the orthopaedic theatre environment

This article is the First Prize winning entry in the Essay Section of the Alison Bell Memorial Writer's Award 2000, sponsored by NATN and Regent. It is based on an essay submitted for the Evidence Based Practice Module of the post-graduate programme in Health Promotion and Health Studies at Bath Spa University College, Bath.

L-dopa-resistant parkinsonism syndrome following cerebral radiation therapy for neoplasm

A bradykinetic form of parkinsonism, unresponsive to levo-dopa therapy developed in four patients two to eight weeks after completion of external beam irradiation (39.2 Gy to 59.4 Gy) of their intracranial neoplasm. In the absence of other causative factors, we relate the movement disorder to radiation-induced changes within the basal ganglia. At post-mortem examination one patient had putamenal gliosis and thickened vessels with loss of nigral neurons.

Tubular peptide hypermetabolism and urinary ammonia in chronic renal failure in man: a maladaptive response?

Excessive renal tubular peptide uptake and degradation reflecting hypercatabolism may be a maladaptive response in chronic renal failure (CRF). It may also offer an explanation for the increased ammoniagenesis, per surviving nephron, observed in CRF but as yet unexplained. Neither has been explored in man. We have shown in patients with normal renal function and heavy (>5.0 g/24 h) proteinuria that tubular catabolism of a technetium-labelled peptide marker, aprotinin, and urinary ammonia were increased compared to others with less proteinuria. We now measure tubular kinetics of aprotinin and urinary ammonia in 16 CRF patients with variable proteinuria. Metabolism and turnover of aprotinin and ammonia excretion were increased, corrected for glomerular filtration rate, to levels found in patients with normal function and heavy proteinuria.

Quantification and characterisation of arteries in retinal images

A computerised system is presented for the automatic quantification of blood vessel topography in retinal images. This system utilises digital image processing techniques to provide more reliable and comprehensive information for the retinal vascular network. It applies strategies and algorithms for measuring vascular trees and includes methods for locating the centre of a bifurcation, detecting vessel branches, estimating vessel diameter, and calculating angular geometry at a bifurcation. The performance of the system is studied by comparison with manual measurements and by comparing measurements between red-free images and fluorescein images. In general an acceptable degree of accuracy and precision was seen for all measurements, although the system had difficulty dealing with very noisy images and small or especially tortuous blood vessels.

Randomised trial of iodine intake and thyroid status in preterm infants

BACKGROUND

Low levels of circulating thyroid hormones have been associated with poorer general and neurodevelopmental outcome in preterm babies and it has been speculated that the association is causal. Low levels of circulating thyroid hormone have been reported after inadequate intake of iodine in preterm infants being fed milk formula.

AIM

To investigate whether increased iodine intake from supplemented preterm formula would improve thyroid hormone levels in preterm babies (this study) and hence improve neurodevelopmental status (planned subsequent study).

METHOD

A total of 121 preterm infants were entered into a randomised controlled trial of standard (68 microg/l) versus increased (272 microg/l) iodine in preterm formula.

RESULTS

The two groups were comparable at recruitment. No evidence of an effect of the intervention on thyroid hormone levels was seen up to 41 weeks after conception.

CONCLUSION

Calls for increased iodine content of preterm infant formulas are not justified by this study.

Increment and decrement detection on temporally modulated fields

Increment and decrement probe thresholds were measured during the presentation of two types of temporal masking stimuli. In Experiment 1, we measured thresholds for increment or decrement rectangular probes presented during the presentation of an increment or decrement Gaussian masking stimulus. We find that thresholds are higher when the probe and the Gaussian mask are of the same sign (e. g. both increments). However, both types of Gaussian mask raised increment and decrement probe thresholds above steady state conditions. In Experiment 2, we presented increment or decrement probes at one of eight possible phases of a 1 Hz luminance-modulated sine wave. For both increment and decrement probes, threshold variation with phase is non-sinusoidal in shape, but increment and decrement probe thresholds vary as a function of the sinusoid phase. These experiments show that increment and decrement thresholds vary as a function of the adaptation state of the visual system, and as a function of the direction of change in the adaptation state. Data from both experiments are discussed in terms of a recent neurophysiological model [Hood & Graham (1998). Threshold fluctuations on temporally modulated backgrounds: a possible physiological explanation based upon a recent computational model. Visual Neuroscience, 15 (5), 957-967]. We find that the predicted ON- and OFF-pathway responses do not correlate in a straightforward manner with the psychophysical thresholds, suggesting that detection of increment and decrement probes may not be performed exclusively by one pathway. Our data have implications for modeling visual performance under conditions where visual adaptation is dynamic, such as when scanning complex images or natural scenes.

Equid herpesvirus 1: platelets and alveolar macrophages are potential sources of activated TGF-B1 in the horse

Cell mediated responses to Equid herpesvirus 1 (EHV-1) are of short duration in vivo and require considerable expansion to be detected in vitro. Raised serum levels of active transforming growth factor B (TGF-B1) have been shown to depress proliferative T cell responses in experimental infections with EHV-1 in ponies. The present work indicates that latent transforming growth factor B (TGF-B1) is present in circulating platelets, lymph node, bronchial epithelium and alveolar macrophages. Activation of platelets in vitro by thrombin resulted in the release of latent TGF-B1 from platelets, with a pg level of conversion to active TGF-B1, but virus alone did not activate TGF-B1. Exposure of circulating leucocytes to EHV-1 in vivo or in vitro does not result in detection of active TGF-B1 above residual levels that could be attributed to activation of platelets by manipulation. However, alveolar macrophages obtained by lavage at autopsy yield both latent and active TGF-B1 in ng quantities. Bronchial epithelium, and mesenteric lymph node leucocytes had equivalent levels of latent TGF-B1, but horses varied as to whether these tissues were a source of activated TGF-B1 and as to whether EHV-1 activated TGF-B1.

What clinical features are most useful to distinguish definite multiple system atrophy from Parkinson's disease?

OBJECTIVES

Few studies have attempted to identify what premortem features best differentiate multiple system atrophy (MSA) from Parkinson's disease (PD). These studies are limited by small sample size, clinical heterogeneity, or lack of postmortem validation. We evaluated the sensitivity and specificity of different clinical features in distinguishing pathologically established MSA from PD.

METHODS

One hundred consecutive cases of pathologically confirmed PD and 38 cases of pathologically confirmed MSA in one Parkinson's disease brain bank were included. All cases had their clinical notes reviewed by one observer (AH). Clinical features were divided into two groups: those occurring up to 5 years after onset of disease and those occurring up to death. Statistical analysis comprised multivariate logistic regression analysis to choose and weight key variables for the optimum predictive model.

RESULTS

The selected early features and their weightings were: autonomic features (2), poor initial levodopa response (2), early motor fluctuations (2), and initial rigidity (2). A cut off of 4 or more on the ROC curve resulted in a sensitivity of 87.1% and specificity of 70.5%. A better predictive model occurred if the following features up to death were included: poor response to levodopa (2), autonomic features (2), speech or bulbar dysfunction (3), absence of dementia (2), absence of levodopa induced confusion (4), and falls (4). The resulting ROC curve based on individual scores showed a best cut off score of at least 11 of 17 (sensitivity 90.3%, specificity 92.6%).

CONCLUSIONS

Predictive models may help differentiate MSA and PD premortem. Hitherto poorly recognised features, suggestive of MSA, included preserved cognitive function and absence of psychiatric effects from antiparkinsonian medication. Diagnostic accuracy was higher in those models taking into account all clinical features occurring up to death. Further studies need to be based on new incident cohorts of parkinsonian patients with subsequent neuropathological evaluation.

Planning and conducting medical support to joint operations

Operations are core business for all of us and the PJHQ medical cell is at the heart of this process. With the likelihood of a continuing UK presence in the Balkans for some time to come, the challenge of meeting this and any other new operational commitments will continue to demand a flexible and innovative approach from all concerned. These challenges together with the Joint and multinational aspects of the job make the PJHQ medical cell a demanding but rewarding place to work and provide a valuable Joint staff training opportunity for the RNMS.

Anticholinesterases in the treatment of Alzheimer's dementia--the first year's experience in Argyll & Clyde

The local experience of the introduction of a new anticholinesterase treatment for Alzheimer's dementia is described, including the use of a protocol to introduce the use of these drugs. The results in the first 233 patients seen are reported. The protocol seemed to anticipate SMAC. guidelines and to be easy to operate; the drug appeared to have clear clinical effect.

The role of nurse practitioners in a primary care eye clinic

This paper reports on a study conducted to audit the practice of nurse practitioners in a primary care eye clinic at St Paul's Eye Unit at the Royal Liverpool University Hospital, UK. The clinic deals with ophthalmic accidents and emergencies and routine referral patients from general practitioners. This was a prospective study of the case notes of 250 consecutive patients who attended the clinic without prior appointment. The study was completed in 1 week.

Provision and staffing of NHS occupational health services in England and Wales

OBJECTIVES

To establish the extent of Occupational Health (OH) service provision in the National Health Service (NHS).

METHODS

Two postal questionnaires were used to obtain information from purchasers and providers in the NHS in England and Wales.

RESULTS

99.6% of trust and health authority employers claim to provide some form of OH service to their employees indicating widespread recognition of need, but virtually no service is provided to other staff such as general practitioners (GPs), general dental practitioners (GDPs), and their staff. There is a wide variability in the range and quality of OH services, suggested by the enormous differences in medical staffing levels, and the contractual restrictions where the OH service is provided by another NHS employer. Only about a third (highest estimate) to a quarter (lowest estimate) of NHS staff have access to a specialist occupational physician.

CONCLUSIONS

Substantial inequality of access to OH services exists for the NHS workforce, despite previous guidance. There is no real evidence to suggest why the extent of provision of OH services varies so greatly between institutions.

Epic as an effective, low toxicity salvage therapy for patients with poor risk lymphoma prior to beam high dose chemotherapy and peripheral blood progenitor cell transplantation

We treated 33 patients with relapsed or refractory non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) with a combination of etoposide, prednisolone, ifosfamide and carboplatin (EPIC). After a median of two courses (range 1-5) complete response was achieved in 7 (22%) patients and partial response in 12 (37%) patients, an overall response rate of 59%. The regimen was well tolerated with myelosuppression being the most common toxicity. There were no toxic deaths. 25 (78%) patients were able to proceed to high dose therapy (BEAM) with peripheral blood progenitor cell transplantation either immediately post EPIC or following further salvage therapy. Most patients mobilised peripheral blood progenitor cells well and 24 out of 25 patients subsequently undergoing autologous transplantation had rapid regeneration of counts. EPIC is an effective salvage therapy in the majority of patients with relapsed or refractory lymphoma and does not appear to be toxic to stem cells. Although severe, myelosuppression is of short duration and the generally low toxicity enables patients to proceed to successful peripheral blood stem cell harvest and transplantation.

Nutritional, respiratory, and psychological effects of recombinant human growth hormone in patients undergoing abdominal aortic aneurysm repair

BACKGROUND

Recombinant human growth hormone (rhGH) has been shown to have powerful anabolic effects and to reduce or even prevent nitrogen catabolism in stressed patients. The effects of rhGH on functional parameters are less clearly defined. The aim of this study was to assess the effects of perioperative rhGH on nutritional markers, skeletal muscle function, and psychological well-being in patients undergoing infrarenal, abdominal aortic aneurysm repair.

METHODS

Thirty-three patients undergoing elective infrarenal abdominal aortic aneurysm repair were randomized to one of three groups: (1) control (n = 12): placebo for 6 days before and after surgery; (2) preop + postop (n = 10): rhGH (Genotropin; Pharmacia Ltd, Uppsala, Sweden) 0.3 IU/kg/d for 6 days before and after surgery; and (3) postop (n = 11): placebo for 6 days before and rhGH 0.3 IU/kg/d for 6 days after surgery. Patients were assessed on days -7 and -1 before surgery and days 7, 14, and 60 after surgery.

RESULTS

Administration of rhGH resulted in increased insulin-like growth factor 1 levels, the increase being significantly more marked in the group given rhGH preoperatively. Preoperative and postoperative rhGH reduced the postoperative decrease in both serum transferrin and grip strength at day 7 by 30% and 70%, respectively. Postoperative respiratory function and arterial oxygenation also were improved, with significant differences in arterial oxygenation between rhGH-treated and untreated groups. No difference in mood was seen between groups after surgery, nor was there any difference between subjective assessment of fatigue scores between groups.

CONCLUSIONS

This pilot study indicates that rhGH administered preoperatively has beneficial effects on skeletal muscle and respiratory function and may be more useful than postoperative rhGH administration alone.

Radiotoxicity of Auger electron-emitting estrogens in MCF-7 spheroids: a potential treatment for estrogen receptor-positive tumors

To approach treatment of micrometastases of steroid receptor-rich cancers using estrogen receptor-directed therapy with Auger electrons, multicellular spheroids of the estrogen receptor-rich human breast cancer cell line, MCF-7, were prepared and exposed to a range of concentrations of an Auger electron-emitting estrogen, E-17alpha-[123I]-iodovinyl-11beta-methoxyestradiol, [123I]IVME2, in vitro. After washing, the treated spheroids were dissociated to single cells and plated for assay of colony survival, whereby we observed a dose-dependent reduction in survival that was inhibited by inclusion of an excess of unlabeled estradiol in the initial incubation with [123I]IVME2. Spheroids of a range of sizes from 40 to 280 microm showed similar sensitivity to the Auger electron-emitting estrogen. The mean lethal dose was approximately 700 decays per cell and corresponded to an initial [123I]IVME2 concentration of less than 0.5 nM. If the control and treated spheroids were not trypsinized but rather were allowed to grow intact, there was not only a significant reduction in the growth of the treated spheroids, but in 18 days nearly half became necrotic, while few control spheroids were necrotic. Considering the low concentrations of Auger electron-emitting estrogen required for a significant reduction in survival, we believe this approach has merit to pursue in vivo, especially in cases where it may be possible to target the steroid receptor-rich micrometastases directly, such as ovarian cancer.

Assessing the comprehension and production of language in young children: an account of the Reynell Developmental Language Scales III

The Reynell Developmental Language Scales III have been designed to test the language abilities of children from 18 months to 7 years. They have been standardized on a large, representative sample of children in the United Kingdom and thereby provide a robust measure of language achievement. These Scales provide clinicians with the means of comparing the performance of children who have been referred for therapy, or who are in therapy, with the performance of a large group of normally developing children. The Scales reflect the developmental progression of normal child language in the early years, focusing on key features of child language acquisition at different stages as well as on features which are known to distinguish language impaired-children from language-normal children. While not claiming that the tests are fully comprehensive, the authors maintain that they afford the clinician with a means of looking at components of language while also gaining some insights into the child's ability to integrate vocabulary and grammar. It is recognized that no test can fully assess every aspect of language; essentially a test must be practical in terms of design and, for screening purposes, sufficiently comprehensive to be used with a large section of children referred. In addition to fulfilling these criteria, the Scales have been designed to provide some diagnostic indicators of areas of difficulty. The aims of the original Scales were to provide a measure of verbal ability that could be compared with mental age, and to provide separate scores for production and comprehension. These aims have also been realized in the new version. Additionally a test has been provided that is consonant with information gained from the intensive research in the field of child language that has taken place since the original Scales were devised. The Scales can reveal information about a child's language abilities not readily available from observation and serve a useful function in both identifying disorder and evaluating therapy. Clinicians are increasingly being asked to demonstrate effectiveness of therapy but are hampered by inappropriate outcome measures (Law 1997). It is hoped that the RDLS III provides a test that is valid and reliable and one that can contribute to both the characterization of speech and language disorders and the measurement of treatment efficacy.

Identification of a novel genetic locus for familial cardiac myxomas and Carney complex

BACKGROUND

Intracardiac myxomas are significant causes of cardiovascular morbidity and mortality through embolic stroke and heart failure. In the autosomal dominant syndrome Carney complex, intracardiac myxomas arise in the setting of lentiginosis and other lesions associated with cutaneous hyperpigmentation, extracardiac myxomas, and nonmyxomatous tumors. Genetic factors that regulate cardiac tumor growth remain unknown.

METHODS AND RESULTS

We used the molecular genetic techniques of linkage analysis to study 4 kindreds affected by Carney complex to determine the genetic basis of this syndrome. Our investigation confirmed genetic heterogeneity of Carney complex. Moreover, genetic linkage analysis with polymorphic short tandem repeats on the long arm of chromosome 17 revealed maximal pairwise LOD scores of 5.9, 1.5, 1.8, and 2.9 for families YA, YB, YC01, and YC11, respectively. Haplotype analysis excluded a founder effect at this locus. These data identify a major 17 cM locus on chromosome 17q2 that contains the Carney complex disease gene.

CONCLUSIONS

The ultimate identification and analysis of the Carney complex disease gene at this human chromosome 17q2 locus will facilitate diagnosis and treatment of cardiac myxomas and will foster new concepts in regulation of cardiac cell growth and differentiation.

Cone contributions to the photopic spectral sensitivity of the zebrafish ERG

Microspectrophotometry studies show that zebrafish (Danio rerio) possess four cone photopigments. The purpose of this study was to determine the cone contributions to the zebrafish photopic increment threshold spectral-sensitivity function. Electroretinogram (ERG) b-wave responses to monochromatic lights presented on a broadband or chromatic background were obtained. It was found that under the broadband background condition, the zebrafish spectral-sensitivity function showed several peaks that were narrower in sensitivity compared to the cone spectra. The spectral-sensitivity function was modeled with L - M and M - S opponent interactions and nonopponent S- and U-cone mechanisms. Using chromatic adaptation designed to suppress the contribution of the S-cones, a strong U-cone contribution to the spectral-sensitivity function was revealed, and the contributions of the S-cones to the M - S mechanism were reduced. These results show that the b-wave component of the ERG receives input from all four cone types and appears to reflect color opponent mechanisms. Thus, zebrafish may possess the fundamental properties necessary for color vision.

A multicenter phase I/II dose escalation study of single-dose cidofovir gel for treatment of recurrent genital herpes

A randomized, double-blind, clinic-initiated, sequential dose-escalation pilot study was performed to compare the safety and efficacy of single applications of 1, 3, and 5% cidofovir gel with placebo in the treatment of early, lesional, recurrent genital herpes at five Canadian outpatient sites. Ninety-six patients began treatment within 12 h of lesion appearance and were evaluated twice daily until healing of the lesion occurred. Cidofovir gel at all strengths significantly decreased the median time to negative virus culture in a dose-dependent fashion (3.0 days in the placebo group versus 2.2, 1.3, and 1.1 days in the 1, 3, and 5% cidofovir gel treatment groups, respectively; P = 0.02, 0.0001, and 0.0003, respectively). A trend toward a reduction in the median time to complete healing in association with treatment was present, but the differences were not statistically significant (5.0 days in the placebo group versus 4.3, 4.1, and 4.6 days in the 1, 3, and 5% cidofovir gel treatment groups, respectively). Application site reactions occurred in 3, 5, 19, and 22% of the patients in these four groups, respectively. Treatment-associated lesion recrudescence with delayed healing, which is suggestive of local toxicity, was observed in three patients treated with 5% cidofovir gel and one patient treated with 3% cidofovir gel. In summary, single-dose application of cidofovir gel confers a significant antiviral effect on lesions of recurrent genital herpes. Additional studies are warranted to further identify the optimal efficacious dose of cidofovir in association with the maximum gel strength that can be tolerated.

The incorporation of lamotrigine into the routine automated sequential trace enrichment of dialysates assay of anticonvulsants

We have extended automated sequential trace enrichment of dialysates and high performance liquid chromatography to include the simultaneous assay of lamotrigine with other anticonvulsant drugs: phenobarbitone, carbamazepine and phenytoin. The procedure is reliable and precise (between-batch coefficients of variation < 2.8%) with no interference from other commonly prescribed drugs. Patients on lamotrigine presented with serum concentrations up to 67 mumol/L with no adverse effects, suggesting that the therapeutic range may need re-appraisal.

Proximal renal tubular peptide catabolism, ammonia excretion and tubular injury in patients with proteinuria: before and after lisinopril

1. Progression to renal failure may be linked to the degree of proteinuria through tubulo-interstitial mechanisms. However, there are no data in man on the kinetics of proximal renal tubular protein catabolism or markers of tubular injury before and after lisinopril. We developed a method to allow such studies, and found increased tubular catabolism of 99mTc-labelled aprotinin (Trasylol) in patients with nephrotic range proteinuria which was associated with increased ammonia excretion. 2. In this study, 10 patients with mild renal impairment (51Cr-EDTA clearance 63.7 +/- 8.3 ml.min-1.1.73 m-2) and heavy proteinuria (8.2 +/- 2.3 g/ 24 h) were given lisinopril (10-20 mg) for 6 weeks. Renal tubular catabolism of intravenous aprotinin was measured before and after lisinopril by renal imaging and urinary excretion of the free radiolabel over 26 h. Fractional degradation was calculated from these data. Fresh timed urine collections were also analysed for ammonia excretion every fortnight from 6 weeks before treatment. Total urinary N-acetyl-beta-D-glucosaminidase and the more tubulo-specific N-acetyl-beta-D-glucosaminidase 'A2' isoenzyme were also measured. 3. After lisinopril proteinuria fell significantly as expected (from 9.5 +/- 1.6 to 4.5 +/- 1.0 g/24 h, P < 0.01). This was associated with a reduction in metabolism over 26 h (from 1.7 +/- 0.1 to 1.2 +/- 0.1% dose/h, P < 0.01) and in fractional degradation of aprotinin (from 0.08 +/- 0.02 to 0.04 +/- 0.007/h, P < 0.04). Ammonia excretion also fell significantly (from 1.2 +/- 0.1 to 0.6 +/- 0.1 mmol/h, P < 0.0001), as did both total urinary N-acetyl-beta-D-glucosaminidase (P < 0.0001) and the N-acetyl-beta-D-glucosaminidase 'A2' isoenzyme (P < 0.015). These observations after lisinopril treatment have not been described previously. There was no significant change in blood pressure nor in glomerular haemodynamics.

Oral sodium bicarbonate reduces proximal renal tubular peptide catabolism, ammoniogenesis, and tubular damage in renal patients

Oral sodium bicarbonate (NaHCO3) is widely used to treat acidosis in patients with renal failure. However, no data are available in man on the effects on proximal renal tubular protein catabolism or markers of tubular injury. We have developed methods to allow such studies, and both increased tubular catabolism of 99mTc-labelled aprotinin (Apr*), as well as tubular damage were found in association with increased ammonia (NH3) excretion in patients with nephrotic range proteinuria. We now examine the effects of reducing renal ammoniogenesis, without altering proteinuria, using oral NaHCO3 in 11 patients with mild/moderate renal impairment and proteinuria. Renal tubular catabolism of Apr* was measured before and after NaHCO3 by renal imaging (Kidney uptake, K% of dose) and urinary excretion of free 99mTcO4- (metabolism, Met% of dose/h) over 26 h. Fractional degradation (Frac) was calculated from Met/K (/h). Fresh urine was also analyzed for NH3 excretion every fortnight from 6/52 before treatment. Total urinary N-acetyl-beta-D-glucose-aminidase (NAG) and the more tubulo-specific NAG "A2" were measured. 51CrEDTA clearance and 99mTc-MAG 3 TER were also assessed. After NaHCO3 Met over 26 h was significantly reduced (from 1.3 +/- 0.2% of dose/h to 0.9 +/- 0.1% dose/hr, p < 0.005), as was Frac of Apr* (from 0.06 +/- .006/h to 0.04 +/- 0.005/hr, p < 0.003). NH3 excretion also fell significantly (from 0.9 +/- 0.2 mmol/h to 0.2 +/- 0.05 mmol/h, p < 0.007), as did both total urinary NAG (from 169 mumol/24 h, 74-642 mumol/24 h to 79 mumol/ 24 h, 37-393 mumol/24 h, p < 0.01), and the NAG 'A2' isoenzyme (from 81.5 mumol/24 h, 20-472 mumol/24 h to 35.0 mumol/24 h, 6-388 mumol/24 h, p < 0.001). Proteinuria remained unaltered, and there was no change in blood pressure nor in glomerular haemodynamics. Oral NaHCO3 may thus pro-tect the proximal renal tubule and help delay renal disease progression.

The study of the effectiveness of chest compressions using the CPR-plus

Effective cardiopulmonary resuscitation (CPR) requires a high level of skill from both healthcare professionals and the lay public. Inadequate chest compressions are a common cause of ineffective CPR. The CPR-plus is a non-invasive, hand-held, simple to use CPR adjunct designed to assist the rescuer to monitor and modify the compression technique during CPR, hopefully resulting in improved rescuer performance and more effective CPR. Forty qualified nurses were evaluated while they performed chest compressions on a training manikin. During simulated two-rescuer CPR (compression/ventilation ratio 5:1) the participants performed 150 compressions at a rate of 80-100 min. Compressions were performed with and without the CPR-plus and the results compared. The use of the CPR-plus was randomised with regard to whether the adjunct or the standard method was used first. The average number of correctly applied compressions was significantly better when the CPR-plus was used: 138.35/150 versus 110.70/150 (p = 0.0001). Improvements in techniques associated with the use of the CPR-plus also included a reduction in excessive application of pressure and incorrect hand position. The device provided reassurance of satisfactory compressions and an indication of impending fatigue in the rescuer.

Retinal vascular network architecture in low-birth-weight men

BACKGROUND

Low birth weight is associated with hypertension and increased cardiovascular mortality, but the mechanism of this association is not known. Hypertension is accompanied by abnormalities of the microvasculature including rarefaction.

OBJECTIVE

To test the hypothesis that low birth weight is associated with an alteration in microvascular architecture.

DESIGN

A stratified random sample of 100 men aged 64-74 years was selected from a cohort of men whose birth weights were known. They were of relatively high or low birth weight ('high' > or = 3700 g, 'low' < or = 3200 g) and high or low systolic blood pressure (high > or = 160 mmHg, low < or = 140 mmHg).

METHODS

Retinal arteriolar geometry was defined in terms of arteriolar bifurcation angles and junction exponents (a measure of the relative diameters of parent and daughter vessels), measured from photographic diapositives using operator-directed image analysis.

RESULTS

Members of low-birth-weight groups had significantly narrower bifurcation angles than did members of high-birth-weight groups (74 +/- 1 degree versus 78 +/- 1 degree, P= 0.017 by analysis of variance). There was no significant difference between angles in members of groups with high and low blood pressures. Neither birth weight nor blood pressure grouping affected junction exponents.

CONCLUSIONS

Narrower bifurcation angles are associated with increased circulatory energy costs and may be related to a lower than normal microvascular density. Our finding of differences in retinal microvascular architecture might reflect a persistent alteration in vascular architecture as a result of an impairment of foetal development and could provide a mechanistic link between low birth weight and subsequently increased cardiovascular risk.

Getting to the bottom of nappy rash. ALSPAC Survey Team. Avon Longitudinal Study of Pregnancy and Childhood

BACKGROUND

Nappy rash accounts for 20% of dermatology consultations in childhood, but its causes are poorly understood.

AIM

To determine the incidence of nappy rash during the first four weeks of life in a geographically defined United Kingdom (UK) population, and to study the factors associated with developing the rash.

METHOD

The data are derived from self-completed questionnaires of parents in the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC). The response rate to a questionnaire about the child administered four weeks after delivery among parents of singleton infants was 87% (12103/13902).

RESULTS

The incidence of nappy rash was 25%. Fourteen highly significant possible causal factors emerged, of which 10 were retained in a logistic regression model: dirtying of nappy, contact with doctor about other problems, history of rashes in joints or skin creases, type of nappy worn, being fed cereal, taken to mother's bed when waking at night, history of cradle cap, general state of health, previous stomach upset, and being only breast-fed. However, the relative risks were generally small.

CONCLUSIONS

The likelihood of nappy rash increases with intercurrent illness and early introduction of cereals. Disposable nappies give little protection, and this finding helps to endorse a recently introduced hospital scheme arising from environmental concerns that encourages parents to use cotton nappies instead of disposables. For many babies, however, the causes of nappy rash remain unknown.

Differential effects on TNF alpha production by pharmacological agents with varying molecular sites of action

This study describes the activation conditions for tumor necrosis factor-alpha (TNF alpha) production in myelomonocytic U937 cells and human primary peripheral blood monocytes in response to lipopolysaccharide (LPS) and/or phorbol 12-myristate 13-acetate (PMA). PMA itself induced only low levels of TNF alpha production with delayed kinetics (e.g. 0.758 +/- 0.128 ng/ml from U937 cells after 48 h) while LPS induced greater levels of TNF alpha production in less time (e.g. 2.083 +/- 0.96 ng/ml from monocytes in 24 h). Pharmacological agents with various molecular sites of action were used to validate the two systems, with the protein serine-threonine kinase inhibitors staurosporine and Ro-31-8220, the protein tyrosine kinase inhibitor herbimycin A (HBA) and dexamethasone exhibiting the greatest potency (IC50S 5-350 nM). In contrast to the effect on TNF alpha production, PMA induced strong phosphorylation/activation of p42/p44mapk in monocytes by 10 min determined in a mobility shift assay, while LPS was a weaker inducer. Additionally, staurosporine (to LPS and PMA) and HBA (to LPS only) inhibited the activation of these mitogen-activated protein kinase (MAPK) isoforms at doses 10-100 fold higher than those required to inhibit maximal TNF alpha production. These data indicate the involvement of the p42/p44mapk signalling pathway in LPS-induced pro-inflammatory cytokine production but suggest that other signalling pathways are also implicated in this phenomenon.

Sleep benefit in Parkinson's disease

Sleep benefit (SB) In Parkinson's disease (PD) is not well characterized. To determine SB frequency, as well as to characterize and correlate it with other disease variables, we evaluated prospectively a consecutive series of 312 PD patients by means of a structured questionnaire: 55% reported having SB and 35% reported that awakening was their best time of the day. Because of SB, 21% of the entire population were able to skip or delay medication. The mean duration of the phenomenon was 85.4 +/- 67 min. Patients with SB were significantly older (p < 0.0002), had disease longer (p < 0.05), and were often men (chi 2 = 3.5, df 1, p = 0.05). Patients with SB took sleep medication with similar frequency as those without SB. There were no differences in hours of sleep or sleep latency. Sleep problems such as nightmares or somnambulism, but not the number of sleep awakenings, were similar in both groups. In conclusion, SB is a frequent phenomenon, especially in men, elderly patients, and patients with longer disease duration. SB enables the morning L-dopa dose to be postponed in approximately 50% of patients.