Synthesis and Antimicrobial Analysis of High Surface Area Strontium-Substituted Calcium Phosphate Nanostructures for Bone Regeneration

Continuous microwave-assisted flow synthesis has been used as a simple, more efficient, and low-cost route to fabricate a range of nanosized (<100 nm) strontium-substituted calcium phosphates. In this study, fine nanopowder was synthesized via a continuous flow synthesis with microwave assistance from the solutions of calcium nitrate tetrahydrate (with strontium nitrate as Sr2+ ion source) and diammonium hydrogen phosphate at pH 10 with a time duration of 5 min. The morphological characterization of the obtained powder has been carried out by employing techniques such as transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller surface area analysis. The chemical structural analysis to evaluate the surface properties was made by using X-ray photoelectron spectroscopy. Zeta potential analysis was performed to evaluate the colloidal stability of the particles. Antimicrobial studies were performed for all the compositions using four bacterial strains and an opportunistic human fungal pathogen Macrophomina phaseolina. It was found that the nanoproduct with high strontium content (15 wt% of strontium) showed pronounced antibacterial potential against M. luteus while it completely arrested the fungal growth after 48 h by all of its concentrations. Thus the synthesis strategy described herein facilitated the rapid production of nanosized Sr-substituted CaPs with excellent biological performance suitable for a bone replacement application.

Curcumin nanoparticles: physicochemical fabrication, characterization, antioxidant, enzyme inhibition, molecular docking and simulation studies

Curcumin is an extensively studied natural compound due to its extensive biological applications. However, there are some drawbacks linked to this compound such as poor absorption, low water-solubility, quick systemic elimination, fast metabolism, poor pharmacokinetics, low bioavailability, low penetration targeting efficacy and low stability. To overcome these drawbacks, curcumin is encapsulated in nano-carriers. In the current studies, we synthesized nanoparticles of curcumin without using nanocarriers by different methods such as nano-suspension (Cur-NSM), sonication (Cur-SM) and anti-solvent precipitation (Cur-ASP) to enhance the solubility of curcumin in water. The prepared nanoparticles were characterized by FTIR, SEM and XRD analysis. These curcumin nanoparticles were screened for their solubilities in water, DPPH scavenging, amylase, α-glucosidase and β-glucosidase enzymatic activities. The particle size of nano-curcumin was found to be in the 47.4-98.7 nm range. The reduction in particle size of curcumin dramatically increases its solubility in water to 79.2 μg mL^-1, whereas the solubility of curcumin is just 0.98 μg mL^-1. Cur-ASP showed the highest free radical scavenging potential (48.84 ± 0.98%) which was comparable with standard BHT (50.48 ± 1.11%) at 75.0 μg mL^-1. As well, Cur-ASP showed the highest inhibition of α-amylase (68.67 ± 1.02%), α-glucosidase (58.30 ± 0.52%), and β-glucosidase (64.80 ± 0.43%) at 100 μg mL^-1 which is comparable with standard drug acarbose. The greater surface area of nanoparticles exposes the various groups of curcumin for blocking the binding sites of enzymes. This strategy may be helpful in designing curcumin as a potent therapeutic agent against diabetes mellitus. Further, the molecular interactions of curcumin with α-amylase, α-glucosidase, β-glucosidase, and polyphenol oxidase were assessed by analyzing the plausible binding modes of curcumin in the binding pocket of each receptor. The best binding mode of curcumin was used to make complexes with the target proteins and their stability was confirmed by 50 ns MD simulation.

Antagonistic activity of Aspergillus versicolor against Macrophomina phaseolina

The present study was carried out to evaluate the antagonistic efficacy of Aspergillus versicolor against the soil and seed inhibiting destructive plant pathogen Macrophomina phaseolina. The tested antagonist was confirmed by rDNA sequencing of ITS and β-tubulin genes with respective accession numbers MN719083 and MN736397. In dual culture bioassays, A. versicolor showed potent antagonist activity and reduced the pathogen's growth by 60% over control. To understand the mechanism of antagonistic fungus, DNA of the pathogenic fungus was incubated in secondary metabolites produced by the A. versicolor for 24 and 48 h. After 48 h, metabolites of A. versicolor fully degraded the DNA of M. phaseolina. Moreover, for the identification of bioactive compounds, the chloroform and ethyl acetate fractions of A. versicolor culture filtrates were subjected to GC-MS analysis. A total of 10 compounds were identified in each of the two fractions. Among these, chondrillasterol (37.43%) followed by 1,2-benzedicarboxylic acid, diisooctyl ester (25.93%), decane (16.63%), 9,12-octadecadienoic acid (Z,Z)- (13.32%), stigmasterol (11.16%), undecane (10.93%), cis-1-chloro-9-octadecene (8.66%), benzene, 1,3,5-trimethyl (8.46%), and hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester (8.13%) were the major compounds. Some of the identified compounds are known to possess strong antifungal, antibacterial, nematicidal, and antioxidant properties. The present study concludes that A. versicolor is an effective antagonist against M. phaseolina.

Biocontrol Aspergillus species together with plant biomass alter histochemical characteristics in diseased mungbean plants

In the present study, two Aspergillus species as biocontrol agents together with Chenopodium quinoa dry biomass were used to investigate their effects on histochemical features of mungbean plant inoculated with M. phaseolina. In a pot experiment, Aspergillus flavipes and Aspergillus versicolor were added either alone or together with 1%, 2%, and 3% dry biomass of quinoa (DBQ) to the pot soil already inoculated with M. phaseolina. After 4 weeks of sowing, root and lower-stem sections of the mungbean plants were stained with ferric chloride, phloroglucinol-HCl and Lugol's iodine to detect the presence of polyphenols, lignin, and starch granules, respectively, and observed under light microscope. Stem and root sections were also observed under scanning electron microscope (SEM) to reveal the effect of soil amendments on cell structures. The findings revealed that mungbean plant cross sections from all the treatments except positive control (only inoculated with M. phaseolina) showed very clear cell structures. In positive control, distorted, fragmented, and collapsed cell structures were observed. Moreover, M. phaseolina blocked vascular vessels in comparison to negative control where the cell structures were intact and normal in size. Plant sections from treatments with A. flavipes and A. versicolor alone or together with DBQ were without pathogen colonization, with normal cell structures and a high deposition of gel. The results suggested that the two Aspergillus spp. and C. quinoa induced defense responses in mungbean plants.

Histopathological changes in root and stem of mungbean exposed to Macrophomina phaseolina and dry biomass of Chenopodium quinoa

Mungbean production is affected by a fungal pathogen Macrophomina phaseolina. A pot experiment was carried out to check the effect of quinoa (Chenopodium quinoa Willd.) dry biomass on the histopathological features of mungbean exposed to M. phaseolina. For this, 1%, 2% and 3% (wt/wt) of C. quinoa dry biomass was mixed in the soil inoculated with M. phaseolina. The highest disease incidence (36%) was recorded in the positive control (only M. phaseolina). Different treatments of quinoa dry mass reduced disease incidence to 4-7%. After 4 weeks of germination, stem and root sections were stained in phloroglucinol-HCl, ferric chloride and Lugol's iodine stains for the detection of lignin, polyphenols and starch granules, respectively, and studied under light microscope. Plants of positive control showed damaged cells, and heavy deposition of lignin, phenolics and starch granules as compared to plants of the negative control and those grown in the soil amended with different doses of dry biomass of quinoa. For better understanding, plant root and stem sections were studied under a scanning electron microscope. Plant sections from positive control exhibited the presence of M. phaseolina sclerotial bodies and hyphal growth, whereas in negative control normal cell structures were observed. However, C. quinoa amended stem and root sections revealed the presence of high gel deposition with normal cell structures and no pathogen establishment. This study concludes that application of C. quinoa is an effective and natural remedy to activate the resistance mechanism in plants and to combat the adverse effects of M. phaseolina.

Green synthesis of coumarin derivatives using Brønsted acidic pyridinium based ionic liquid [MBSPy][HSO4] to control an opportunistic human and a devastating plant pathogenic fungus Macrophomina phaseolina

An eco-friendly simple protocol has been devised for the preparation of coumarin derivatives using doubly Brønsted acidic task specific ionic liquid (TSIL) as a catalyst. Solvent-free conditions were employed for the reaction of different substituted phenols with β-ketoester in TSIL to produce corresponding substituted coumarin derivatives in good to excellent yields at ambient conditions; at room temperature and with reduced reaction times. The ionic liquid catalyst can be recycled and reused up to five times. All the synthesized coumarins were evaluated for their antifungal activities against Macrophomina phaseolina, a plant as well as an opportunistic human pathogenic fungus affecting more than 500 plant species worldwide and with no registered commercial fungicide available against it, to date. Amongst all the coumarins tested, compounds 3f and 3i showed excellent antifungal activity comparable to reference fungicide mancozeb. The current methodology provides an easy and expedient way to access the coumarin core in search of potential fungicides for sustainable agriculture.

An eco-friendly simple protocol has been devised for the preparation of coumarin derivatives using doubly Brønsted acidic task specific ionic liquid (TSIL) as a catalyst.

Analysis of NHSLA claims in hand and wrist surgery

Claims for negligence are increasing in medical practice. We analysed data provided by the UK NHS Litigation Authority (NHSLA) on all hand and wrist surgery from 1995-2001. The numbers of claims increased from 13 to 40, but the number being successfully defended also increased from 2 to 13 during this period. Claims were most commonly attributed to errors at surgery (56%) or in outpatient clinics (24%). Strikingly the claims are clustered to a few common conditions, particularly the treatment of carpal tunnel syndrome (22%) and wrist fractures (48%). There were no claims related to complex hand surgery. We recommend better training for 'routine surgery', better description of distal radius fracture parameters at each clinic visit and better training in emergency departments (ED).

Proliferative glomerulonephritis with acute renal failure-a rare manifestation in seronegative rheumatoid arthritis

A 55 years old lady with advanced rheumatoid arthritis (RA) presented with severe acute renal failure with significant proteinuria preceded by fever for 14 days. She had no history of taking drugs usually responsible for glomerulonephritis, neither had she any clinico-biochemical evidence of peri-infectious glomerulonephritis. Acute interstitial nephritis (AIN) was excluded by absence of eosinophilia and eosinophils in urine. Renal biopsy reveled absence of amyloidosis and showed Focal segmental proliferative glomerulonephritis (FSGN). Patient was successfully managed with methyl-prednisolone followed by steroid and immunosuppressive and patient came over renal failure. So FSGN should be considered as one of the causes of acute renal failure in a patient with seronegative RA which may respond to immune-therapy like rapidly progressive glomerulonephritis.

Use of genomic analysis of varicella-zoster virus to investigate suspected varicella-zoster transmission within a renal unit

BACKGROUND

The source of hospital-acquired chickenpox infection may be presumed from a known exposure, but has not been previously proven using genomic analysis.

OBJECTIVE

Investigation of suspected VZV transmission was done using single nucleotide polymorphism genomic analysis.

STUDY DESIGN

Comparison was made of viral isolates from two patients with chickenpox on the same ward who were not known to have had direct contact.

RESULTS

An identical genotype in the variable R1 region of the VZV was isolated from the two patients.

CONCLUSION

Inapparent hospital-acquired transmission was the most likely route of infection.

Hospitalization in the first year of renal replacement therapy for end-stage renal disease

BACKGROUND

The requirement for hospitalization of patients on dialysis is likely to be a surrogate marker of age and comorbid diseases. It may also reflect the level of care delivered, and substantially increases the cost of this expensive therapy.

AIM

To identify the factors most strongly associated with hospitalization.

DESIGN

Prospective population study.

METHODS

Data were recorded for all patients starting RRT in Scotland over one year, including the reasons for and duration of, each hospital admission during the first year of RRT. Factors most strongly associated with hospitalization were determined by Poisson regression analysis.

RESULTS

Overall, 526 patients were admitted to hospital on 1668 occasions (median 3, IQR 1-4) for 13384 days (median 13, IQR 4-35). Formation of vascular access for haemodialysis (HD) was the most frequent reason for admission, followed by infections. Age, comorbidity, mode of presentation for RRT and primary renal diagnosis were all significantly associated with prolonged hospitalization. Attainment of UK Renal Association standards for urea reduction ratio and serum albumin concentration, and vascular access in the form of arterio-venous fistulae were associated with less hospitalization in patients treated with HD by 90 days.

DISCUSSION

Patients in their first year of RRT have a high requirement for in-patient care, 8.6% of patient treatment days being spent in hospital. Vascular access formation, failure and complications account for a large proportion of this. Age and comorbidity prolong the time spent in hospital. As the RRT population continues to increase, with older patients and those with greater comorbidity, in-patient facilities must also expand.

Interwell tracing by environmental isotopes at Fimkassar Oilfield, Pakistan

Water flooding is an important operation to enhance oil recovery. Movement of injected water is traced to test the performance of the water flood and verify suspected geological barriers or flow channels, etc. This paper describes the application of environmental isotopes as interwell tracers at Fimkassar Oilfield in Chakwal District, Pakistan. Water flooding was started in March 1996 in the Sakessar formation (Eocene). When water appeared in the production well in June 1998, isotopes (18O, 2H and 3H) were used to determine the breakthrough/transit time of the water flood and the contribution of fresh injected water. Water samples were collected during June 1998-August 1999 from the injection well, the production well, and some other fields for reference indices of the Sakessar formation and analyzed for the 18O, 2H and 3H, and chloride contents. The isotopic results confirmed the breakthrough of injected water and indicated that the water in the production well was a mixture of the injected water and the formation water. The initial breakthrough time was 27 months. The contribution of injected water varied from 67% to 80%. This percentage did not change significantly from the time of breakthrough until the last sampling indicating good mixing in the reservoir and the absence of any high permeability channel. Chloride content did not give any information about the hydraulic connection between the injection well and the production well. The study proved the potential of environmental isotopes for interwell tracing.

Acute renal failure requiring renal replacement therapy: incidence and outcome

BACKGROUND

Renal replacement therapy (RRT) for acute renal failure (ARF) may be provided in many settings within the hospital. Such patients require a high level of care and often have a poor prognosis. No prospective studies have accurately defined this population, making the prediction of necessary resources and the planning of services difficult.

AIM

To ascertain the incidence, causes and outcomes of acute renal failure requiring renal replacement therapy in Scotland.

DESIGN

A prospective observational census of all clinical areas providing renal replacement therapy in three Scottish health boards (Grampian, Highland, Tayside).

METHODS

Patients were identified by liaison with each unit providing RRT. Factors precipitating renal failure and reasons for RRT were recorded at the time of initiation. Comorbid disease burden was scored using the Charlson index. Patient status at 90 days was assessed from case-notes, contacting general practitioners where necessary.

RESULTS

375 patients per million population per year received RRT; 203 per million per year for either ARF or acute-on-chronic renal failure. 73.5% of patients receiving RRT for ARF died within 90 days, 23.5% became independent of RRT. The median duration of hospital admission was 19 days.

DISCUSSION

The annual incidence of ARF requiring RRT is just over 200 per million population, almost twice that of end-stage renal disease requiring RRT. Such treatment places high demands upon health care resources.

Performance of stochastic approaches for forecasting river water quality

This study analysed water quality data collected from the river Ganges in India from 1981 to 1990 for forecasting using stochastic models. Initially the box and whisker plots and Kendall's tau test were used to identify the trends during the study period. For detecting the possible intervention in the data the time series plots and cusum charts were used. The three approaches of stochastic modelling which account for the effect of seasonality in different ways. i.e. multiplicative autoregressive integrated moving average (ARIMA) model. deseasonalised model and Thomas-Fiering model were used to model the observed pattern in water quality. The multiplicative ARIMA model having both nonseasonal and seasonal components were, in general, identified as appropriate models. In the deseasonalised modelling approach, the lower order ARIMA models were found appropriate for the stochastic component. The set of Thomas-Fiering models were formed for each month for all water quality parameters. These models were then used to forecast the future values. The error estimates of forecasts from the three approaches were compared to identify the most suitable approach for the reliable forecast. The deseasonalised modelling approach was recommended for forecasting of water quality parameters of a river.

Origin of whales from early artiodactyls: hands and feet of Eocene Protocetidae from Pakistan

Partial skeletons of two new fossil whales, Artiocetus clavis and Rodhocetus balochistanensis, are among the oldest known protocetid archaeocetes. These came from early Lutetian age (47 million years ago) strata in eastern Balochistan Province, Pakistan. Both have an astragalus and cuboid in the ankle with characteristics diagnostic of artiodactyls; R. balochistanensis has virtually complete fore- and hind limbs. The new skeletons are important in augmenting the diversity of early Protocetidae, clarifying that Cetacea evolved from early Artiodactyla rather than Mesonychia and showing how early protocetids swam.

Do the Y-set and double-bag systems reduce the incidence of CAPD peritonitis? A systematic review of randomized controlled trials

BACKGROUND

Peritonitis is the most frequent serious complication of continuous ambulatory peritoneal dialysis (CAPD). It has a major influence on the number of patients switching from CAPD to haemodialysis and has probably restricted the wider acceptance and uptake of CAPD as an alternative mode of dialysis. This systematic review sought to determine if modifications of the transfer set (Y-set or double-bag systems) used in CAPD exchanges are associated with a reduction in peritonitis and an improvement in other relevant outcomes.

METHODS

Based on a comprehensive search strategy, we undertook a systematic review of randomized or quasi-randomized controlled trials comparing double-bag and/or Y-set CAPD exchange systems with standard systems, or comparing double-bag with Y-set systems, in patients with end-stage renal disease (ESRD) treated with CAPD. Only published data were used. Data were abstracted by a single investigator onto a standard form and subsequently entered into Review Manager 4.0.4. Its statistical package, Metaview 3.1, calculated an odds ratio (OR) for dichotomous data and a (weighted) mean difference for continuous data with 95% confidence intervals.

RESULTS

Twelve eligible trials with a total of 991 randomized patients were identified. In trials comparing either the Y-set or double-bag systems with the standard systems, significantly fewer patients (133/363 vs 158/263; OR 0.33, 95% CI 0.24-0.46) experienced peritonitis and the number of patient-months on CAPD per episode of peritonitis was consistently greater. When the double-bag systems were compared with the Y-set systems significantly fewer patients experienced peritonitis (44/154 vs 66/138; OR 0.44, 95% CI 0.27-0.71) and the number of patient-months on CAPD per episode of peritonitis was also greater.

CONCLUSIONS

Double-bag systems should be the preferred exchange systems in CAPD.

Evidence-based medicine in nephrology: identifying and critically appraising the literature

BACKGROUND

Uncertainties about best management of end-stage renal disease (ESRD) are reflected in wide variations in practice. Systematic reviews aim to reduce uncertainty by strengthening the evidence base for clinical practice, allowing estimation of the benefits and risks of particular interventions, whilst minimizing the potential for bias. This paper describes the methods and conduct of six systematic reviews of aspects of the management of ESRD, and the yield in terms of trials found.

METHODS

Our methodology was based on that recommended by the Cochrane Collaboration (an international initiative set up to perform and disseminate systematic reviews of health care). It involved a systematic search of electronic databases and bibliographic reference lists, together with handsearching of Kidney International for studies relevant to the management of ESRD, followed by a systematic assessment of study quality.

RESULTS

Around 12,000 abstracts were assessed which had been identified from electronic sources. Of these, 2085 (18%) were deemed to be reports of possible randomized or quasi-randomized controlled trials relevant to the management of ESRD. Three hundred and forty were relevant to the six specific reviews, and after assessment of the full manuscripts, 39 studies were finally included in our reviews. Reports of a further nine trials, which were identified from other sources, were also included. The broad search adopted allowed the parallel development of a register of trials of all aspects of the management of ESRD.

CONCLUSIONS

This study has demonstrated that the methodology of systematic reviews, as promoted by the Cochrane Renal Group, is feasible but has significant resource implications. The development of a register of randomized controlled trials (RCTs) related to the management of ESRD will facilitate this form of research in the future.

Muscle sparing thoracotomy: a biomechanical analysis confirms preservation of muscle strength but no improvement in wound discomfort

OBJECTIVES

This study compares the posterior auscultatory triangle thoracotomy incision (muscle sparing) with full posterolateral thoracotomy (where latissimus dorsi muscle is always cut across its full width), with particular attention to the difference between latissimus dorsi muscle strength, post operative pain and chronic wound related symptoms.

METHODS

Ten patients who had undergone auscultatory triangle thoracotomy (ATT) at least 1 year previously were matched with ten patients who had undergone posterolateral thoracotomy (PLT). Each pair was matched for age, sex, dominant hand, side of the operation, time since operation and presence or absence of history of previous muscle training. Latissimus dorsi muscle strength was assessed by testing the shoulder adduction strength through an arc of 90-0 degrees using isokinetic technique. Early post-operative pain was assessed indirectly by calculating the analgesic requirement in the first 5 post-operative days. A subjective assessment of chronic post-thoracotomy pain was made using a questionnaire presented to the patients at the time of muscle testing. Variability of the torque curves, recorded as coefficient of variance at the time of muscle strength testing, provided objective measurements of chronic pain. Data were analysed using two sample t-tests.

RESULTS

All patients reported at least one chronic post-thoracotomy symptom. There was no significant difference between the two groups in terms of acute or chronic wound pain and other long term wound related symptoms. Shoulder adduction strength was 24% greater in ATT than PLT (95% confidence limits=1-43%, P=0.04).

CONCLUSIONS

All thoracotomy patients have long term wound related symptoms. This situation is not improved by performing a muscle sparing incision. However thoracotomy through the triangle of auscultation can preserve latissimus dorsi strength which is compromised in a posterolateral thoracotomy incision. We therefore recommend that a muscle sparing thoracotomy be considered for patients where preservation of muscle strength is deemed important, providing the operation is not compromised due to inadequate access.

Evaluation of clinical guidelines for the management of end-stage renal disease in europe: the EU BIOMED 1 study

BACKGROUND

There are wide national and international variations in the management of patients with end-stage renal disease (ESRD). The aim of this study was to develop, harmonize, implement, and evaluate consensus-based clinical guidelines for the management of renal anaemia and renal bone disease in patients with ESRD, and for the prevention and management of cytomegalovirus disease in renal transplant recipients across six renal centres in Europe.

METHODS

The trial was a prospective, multicentre, randomized balanced incomplete block design. Nephrologists from the six European renal units were randomized to develop and implement guidelines for two out of the three conditions and to act as a control for the third condition. Data were collected pre- (1 year) and post- (9 months) intervention on aspects of patient monitoring, management, and outcome.

RESULTS

Eight hundred and twenty-nine dialysis patients from the six European dialysis centres were included in the study. Multivariate analysis (adjusting for case-mix and secular trends) showed a significant increase in the number of monitoring events in the guideline group compared with control group (6%, 95% CI, 1-11%). There was no concomitant increase in either appropriate management or the number of favourable patient outcomes.

CONCLUSIONS

In the first European collaboration on renal guidelines, the introduction of the guidelines improved the monitoring of the patients, but did not improve patient management or outcome. This study suggests the potential for creating clinical guidelines with the aim of standardizing treatment protocols across international boundaries, and improving the quality of the medical care provided.

Can we improve early mortality in patients receiving renal replacement therapy?

BACKGROUND

Approximately one in eight patients with end-stage renal disease (ESRD) die within the first three months of starting renal replacement therapy (RRT). We investigated which factors might improve this early mortality.

METHODS

We performed a prospective nationwide study of all patients commencing RRT for ESRD in Scotland over one year. Patients were classified according to how they presented to start RRT, their burden of comorbid diseases, access prepared for dialysis, and duration of care by a nephrologist prior to commencing RRT. Those factors most strongly associated with death within 90 days of commencing treatment were determined by logistic regression analysis.

RESULTS

Patients with an acute unexpected element to their presentation for RRT had early mortality rates between 6.0 and 8.9 times greater than those who commenced RRT electively after a period of care from a nephrologist. Patients in high and medium comorbidity risk groups had early mortality rates of 4.7 and 2.2 times greater than those in the low-risk group. Low serum albumin had a significant association with early death. Patients who progressed steadily to ESRD, who had a planned start to dialysis, and who had mature access were 3.6 times more likely to survive beyond three months than those with no access; they were, however, also younger with less comorbidity.

CONCLUSIONS

The factors principally associated with early mortality are nonelective presentation for RRT, comorbid illness, and low serum albumin. Patients cared for by a nephrologist before requiring RRT who have mature access have better short-term survival than those without access. They are also younger with less comorbidity. It may be possible to improve short-term survival in this "unplanned" group if referred early to facilitate reducing cardiovascular risk factors and preparation for RRT.

Equity of renal replacement therapy utilization: a prospective population-based study

This 1-year prospective survey assessed the incidence and characteristics of all patients starting renal replacement therapy (RRT) for end-stage renal disease in Scotland, and whether there is equity of utilization of RRT in terms of age, domicile and social circumstance. In the year studied, 104 patients per million population (533 patients) started RRT (390 per million population aged 65-75). In 23.5% the cause of ESRD could not be determined. Diabetes was the single most frequently identified cause (16%). The requirement for RRT rose with age, but over the country as a whole, patients aged over 75 years were under-represented. The majority of health boards provided RRT at a rate within 20% of the national rate. There was no difference in the median age at starting RRT between health boards. The spectrum of social deprivation of patients starting RRT was the same as that of the general population. There was no evidence that social deprivation influences acceptance on to the RRT program, although the relationship between ESRD and deprivation is complex. The utilization of RRT exceeded the minimum rate recommended by the Renal Association, although there was fluctuation between health board areas. The national requirement for resources to provide RRT is likely to rise further to care for an increasingly elderly population.

Glycoside primers of Psittacanthus cucullaris

Bioassay-directed chromatographic separation of the ethyl acetate extract of the whole plant of Psittacanthus cucullaris afforded a new phenolic xyloside, ellagic acid-4-O-beta-xyloside-3,3', 4'-trimethyl ether (1) together with four known compounds, ellagic acid-4-O-beta-xyloside-3,3'-dimethyl ether (2), gallic acid, beta-sitosterol, and beta-sitosterol beta-D-glucoside. The structure of the new compound was determined by spectroscopic methods. Like other beta-D-xylosides, compounds 1 and 2 stimulated the formation of glycosaminoglycan chains when fed to the cultured Chinese hamster ovary cells.

A national survey of thoracic surgical practice in the UK

We conducted a survey of thoracic surgery in the UK today. Questionnaires were sent to 75 cardiothoracic surgeons, known to perform thoracic surgery regularly; we had a 100% response. The commonest preoperative investigations for carcinoma of the oesophagus were serum alkaline phosphatase (90%), GGT (69%), contrast swallow (80%), ultrasound of abdomen (71%) and CT scan of chest and abdomen (60%). After oesophagectomy, 84% of the surgeons inserted nasogastric tubes and 31% sent their patients to the intensive care unit. Oral fluids were started on days 3-5 in 81% of cases, and 58% of the surgeons requested a postoperative contrast swallow, usually between the seventh and tenth postoperative days, after oral fluids had been started. Most of the surgeons nearly always used staplers for a given procedure or else completely avoided them for that part of the operation. The commonest use of staplers was for bronchial closure in pneumonectomy (67%) and lobectomy (48%) and in constructing an oesophageal anastomosis (25%). Twenty per cent of the surgeons did not insert a chest drain after pneumonectomy, while 65% observed the protocol of chest drain insertion with short intermittent unclamping, usually every hour, followed by removal of the drain, usually the next morning. Thoracic surgeons vary widely in their surgical practices. In a well structured training programme, trainees should rotate between several units so they are exposed to different techniques and ideas and acquire a broad based training.

Role of the SH3-ligand domain of simian immunodeficiency virus Nef in interaction with Nef-associated kinase and simian AIDS in rhesus macaques

The nef gene of the human and simian immunodeficiency viruses (HIV and SIV) is dispensable for viral replication in T-cell lines; however, it is essential for high virus loads and progression to simian AIDS (SAIDS) in SIV-infected adult rhesus macaques. Nef proteins from HIV type 1 (HIV-1), HIV-2, and SIV contain a proline-Xaa-Xaa-proline (PxxP) motif. The region of Nef with this motif is similar to the Src homology region 3 (SH3) ligand domain found in many cell signaling proteins. In virus-infected lymphoid cells, Nef interacts with a cellular serine/threonine kinase, designated Nef-associated kinase (NAK). In this study, analysis of viral clones containing point mutations in the nef gene of the pathogenic clone SIVmac239 revealed that several strictly conserved residues in the PxxP region were essential for Nef-NAK interaction. The results of this analysis of Nef mutations in in vitro kinase assays indicated that the PxxP region in SIV Nef was strikingly similar to the consensus sequence for SH3 ligand domains possessing the minus orientation. To test the significance of the PxxP motif of Nef for viral pathogenesis, each proline was mutated to an alanine to produce the viral clone SIVmac239-P104A/P107A. This clone, expressing Nef that does not associate with NAK, was inoculated into seven juvenile rhesus macaques. In vitro kinase assays were performed on virus recovered from each animal; the ability of Nef to associate with NAK was restored in five of these animals as early as 8 weeks after infection. Analysis of nef genes from these viruses revealed patterns of genotypic reversion in the mutated PxxP motif. These revertant genotypes, which included a second-site suppressor mutation, restored the ability of Nef to interact with NAK. Additionally, the proportion of revertant viruses increased progressively during the course of infection in these animals, and two of these animals developed fatal SAIDS. Taken together, these results demonstrated that in vivo selection for the ability of SIV Nef to associate with NAK was correlated with the induction of SAIDS. Accordingly, these studies implicate a role for the conserved SH3 ligand domain for Nef function in virally induced immunodeficiency.

Comparing outcomes in renal replacement therapy: how should we correct for case mix?

The need to evaluate the effectiveness of clinical practice to justify expensive therapy in the face of financial constraints in all areas of health care delivery makes it necessary to identify groups of patients who are likely to benefit most from treatment. Various risk stratification methods have been used for analyzing survival probabilities for patients receiving renal replacement therapy. Complicated risk stratification methods produce large numbers of risk groups of small sizes, which makes comparison between individual centers difficult. We compared three simple methods of risk stratification, that divided patients into low-, medium-, and high-risk groups, in a cohort of 1,407 patients who commenced renal replacement therapy in five European countries during a 7-year period. Method 1 considered age (>55 years) and diabetes alone; method 2 used a higher age limit (>70 years) and comorbid illnesses, including those other than diabetes; and method 3 used only the number of comorbidities (none, 1, or > or =2) for stratification. Kaplan-Meier survival curves were constructed for comparison between risk groups and Cox's regression model used to assess strength of relationship with mortality. Although patient survival was significantly different between the low-, medium-, and high-risk groups using all three methods, Cox's regression analysis showed that method 2 provided the greatest discrimination between risk groups. In predicting mortality, method 2 (based on comorbidities and age) showed the highest sensitivity and specificity (84% and 80%, respectively) compared with method 1 (80% and 74%) and method 3 (64% and 82%). Validation of this approach in other populations in a prospective study is required before this method, which takes into account the influences of both age and comorbidity for risk stratification, can be used for comparing survival data and for presenting results of renal replacement therapy.

Celestin blister with obstruction

Images

Acute renal failure: factors influencing nephrology referral and outcome

We investigated the incidence, factors affecting referral and outcome of acute renal failure (ARF), in an unselected (predominantly Caucasian) population in the Grampian region of Scotland served by a single renal unit. Case-notes were examined for all patients with a serum creatinine > or = 300 mumol/l. ARF (311 patients) was defined as a temporary rise in serum creatinine > or = 300 mumol/l, or, if the patient died during the acute illness, clinical features indicating acute deterioration of previously normal renal function. Advanced ARF at presentation (51 of the 311 with ARF) was defined as a first recorded serum creatinine > or = 500 mumol/l. Patients were classified into low-, medium-, and high-risk groups according to presence of comorbidity and age. The annual incidence of ARF was 620/million population (pmp), that of advanced ARF 102 pmp. The age-related incidence of ARF ranged from 30 pmp in the age group (0-19 years) to 4266 pmp in the age group > 80 years. Overall, 22% were referred to a nephrologist (34% after excluding those with advanced cancer and age > 80 years). Referral of patients decreased from 100% in the age group 0-19 to 5% in those > 80 years. Referrals in the low-, medium- and high-risk groups were 75%, 30% and 14%, respectively. Patient survival at 2 years was 80%, 42% and 19% for low-, medium-, and high-risk groups, respectively (86%, 44% and 32% for referred patients). Referral and outcome in patients with ARF were significantly influenced by age and presence of comorbidity at presentation.

Monthly measurements of intraocular pressure in normal, ocular hypertensive, and glaucoma male subjects of same age group

BACKGROUND

Recently it has been shown that environmental conditions have a significant influence on intraocular pressure (IOP). Due to differences in inherent constitution, diet and environmental conditions, there is a clear need for well collected IOP data in different countries and ethnic groups. The seasonal variation of IOP has never been described in Pakistani subjects.

METHODS

IOP was measured each month over the course of 12 months with the Goldmann applanation tonometer in normal, ocular hypertensive, and glaucoma male subjects.

RESULTS

In all groups, the average intraocular pressures in the winter months were highest, while lowest in summer months. The intraocular pressures of spring and autumn months were nearly the same. The intraocular pressure levels in these seasons were between the IOP levels in summer and winter seasons. The difference between highest and lowest IOP was 1.4 +/- 0.2, 3.1 +/- 1.4, and 2.3 +/- 1.1 mmHg, in normal, ocular hypertensive, and glaucoma subjects, respectively. The ups and downs of intraocular pressure were greater in the ocular hypertensive subjects than in the glaucoma patients.

CONCLUSIONS

This study confirms that season influences IOP, and concludes that seasonal influence is highest in ocular hypertensive than in normal and glaucoma subjects. As compared to other nations, effect of seasons on IOP seems to be somewhat less pronounced in Pakistan.

Scleroderma, D-penicillamine treatment, and progressive renal failure associated with positive antimyeloperoxidase antineutrophil cytoplasmic antibodies

Progressive renal failure in patients with scleroderma is a sinister development that is usually attributed to impaired renal blood flow. In some exceptional cases, the underlying pathology is a crescentic glomerulonephritis, which has been associated with positive antineutrophil cytoplasmic antibodies, and in particular antimyeloperoxidase antibodies. The prognosis in such cases has been very poor. We report such a patient whose renal function has improved and stabilized on immunosuppressive therapy.

The effect of exercise training on physical fitness and plasma lipids in young Chinese men and women

BACKGROUND

The mortality from coronary heart disease (CHD) has been steadily increasing in many parts of the world. Measures to reduce the incidence of CHD were initially addressed mainly to middle aged and elderly population groups, but for effective prevention of CHD, measures addressed to younger age groups are also necessary. Moreover, differences between male and female plasma lipid changes after exercise training are not known exactly.

METHODS

The concentrations of plasma lipids, before and after regular physical exercise training for 12 weeks, were analyzed in 25 male and 25 female medical students of the same age group. Physical fitness was evaluated by the measurement of maximum oxygen uptake.

RESULTS

Results indicated that plasma tri-glyceride, HDL-cholesterol, LDL-cholesterol and VLDL-cholesterol differences between the before-and-after exercise were significant (p < 0.05) in males while the differences of plasma total cholesterol were found to be insignificant. In females there were no significant changes in the plasma lipids levels. In both males and females, the marked increase in maximal O2 uptake after exercise training indicated an improvement in physical fitness.

CONCLUSIONS

This study concludes that a short-term exercise program can improve plasma lipid and lipoprotein patterns more in males than in females. It also suggests that daily physical exercise may be an important prevention for cardiovascular diseases in later life, so it is essential to establish a life style with optimum nutrition and physical activity in both the young and in adults of all ages.

Characterization of flagella genes of Agrobacterium tumefaciens, and the effect of a bald strain on virulence

Agrobacterium tumefaciens produces flagella that are arranged circumthecally near one end of the bacilliform cell. The flagella are required for motility to facilitate reaching the root surface, and possibly aid in orientating the bacterial cells at various sites for infection. We have identified three flagella genes designated flaA, flaB, and flaC. Mutations in flaA, flaB and flaC result in abberant swimming behaviour. Electron microscopic examination of these mutants revealed the defective flagella. A non-motile, bald mutant strain was generated by deleting all three fla genes. Nucleotide sequencing of flaA, flaB, and flaC showed that they have a potential coding capacity for polypeptides of 307, 321, and 314 amino acid residues, respectively. The predicted amino acid sequences of the A. tumefaciens FlaA and FlaB proteins are similar (66% average identity) to the FlaA and FlaB proteins encoded by flaA and flaB genes, respectively, in Rhizobium meliloti. There was no counterpart FlaC protein reported in R. meliloti, but the A. tumefaciens FlaC is similar in amino acid sequence to the R. meliloti FlaA (59.8% identity) and FlaB (66.7% identity). Distinct from FlaA and FlaB of R. meliloti is the absence of histidine and cysteine residues and their shorter length (by 88 amino acid residues fewer than FlaA and FlaB of R. meliloti). The transcriptional start sites of each fla gene determined by primer extension revealed consensus-sequence boxes representing potential binding sites for sigma 28 RNA polymerase (RNAP) upstream of the transcriptional start of each fla gene. Besides the potential sigma 28-binding site upstream of flaC, also present are additional putative conserved sequences, GC at -11 and GG at -21 from the transcriptional start, that resemble potential binding motifs for sigma 54. Because the sigma 54 promoter is associated with genes regulated by physiological changes in various bacteria, the flaC gene might be similarly regulated in response to A. tumefaciens responding to host plant stimuli. Virulence studies showed that the bald strain was consistently reduced in virulence below that of the parental wild-type strain by at least 38%. The difference is statistically significant and suggests that the flagella may play a role in facilitating virulence.

Activation of PAK by HIV and SIV Nef: importance for AIDS in rhesus macaques

BACKGROUND

The primate lentiviruses, human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) and simian immunodeficiency virus (SIV), encode a conserved accessory gene product, Nef. In vivo, Nef is important for the maintenance of high virus loads and progression to AIDS in SIV-infected adult rhesus macaques. In tissue culture cells expressing Nef, this viral protein interacts with a cellular serine kinase, designated Nef-associated kinase.

RESULTS

This study identifies the Nef-associated kinase as a member of the p21-activated kinase (PAK) family of kinases and investigates the role of this Nef-associated kinase in vivo. Mutants of Nef that do not associate with the cellular kinase are unable to activate the PAK-related kinase in infected cells. To determine the role of cellular kinase association in viral pathogenesis, macaques were infected with SIV containing point-mutations in Nef that block PAK activation. Virus recovered at early time points after inoculation with mutant virus was found to have reverted to prototype Nef function and sequence. Reversion of the kinase-negative mutant to a kinase-positive genotype in macaques infected with the mutant virus preceded the induction of high virus loads and disease progression.

CONCLUSIONS

Nef associates with and activates a PAK-related kinase in lymphocytes infected in vitro. Moreover, the Nef-mediated activation of a PAK-related kinase correlates with the induction of high virus loads and the development of AIDS in the infected host. These findings reveal that there is a strong selective pressure in vivo for the interaction between Nef and the PAK-related kinase.

The epidemiology of chronic renal failure and provision of renal services in Albania

Tirana, the only dialysis facility in Albania (pop 4 million), has a stock of 12 patients and three haemodialysis machines. To determine the need for renal services in Albania we studied the incidence and outcome of patients with chronic renal failure (CRF) referred to the renal service in Tirana (pop 300 000) over 1 year. Case-notes of all patients with a serum creatinine concentration > or = 300 mumol/l during the study period (1992) were examined and outcome at 2 years recorded for each patient. In all, 84 patients (mean age 41.6 +/- 17.5 years, 56% male) were referred to nephrologists of whom 35 (42%) came from Tirana, giving an annual incidence of 116 per million pop. 77% were under 40 and had no co-morbid illness. Glomerulonephritis, the most common renal diagnosis, affected 26% patients. 22% patients (mean age 38 +/- 18.1) died within 2 years and only 5% received dialysis. The mean age of those who received dialysis was 29 +/- 8.3 compared with those who were not dialysed (42 +/- 18.0). The 59 patients (24 from Tirana i.e. 80 per million) who were alive with advanced CRF (creatinine > 500) had a mean creatine of 623 +/- 93 mumol/l and would be candidates for dialysis. Patients with progressive renal failure in Albania are regularly followed and treated with antihypertensives and dietary modification. The need for RRT, however, is not being met even for young patients with no co-morbidity.

Survival on renal replacement therapy in Europe: is there a 'centre effect'?

OBJECTIVE

Survival is the ultimate outcome measure in renal replacement therapy (RRT) and may be used to compare performance among centres. Such comparison, however, is meaningless if the influences of comorbidity, age and early deaths are not considered. We therefore studied survival rates on RRT in seven centres in Europe after taking into account the influence of age, early deaths, primary renal diagnoses, and comorbidity.

DESIGN

A retrospective survival analysis was carried out on 1407 patients who commenced RRT in seven centres across five European countries during a 7-year period. Patients were stratified into low-, medium- and high-risk groups based mainly on comorbidity and to a lesser extent on age at commencement of RRT. Kaplan-Meier survival and Cox's proportional hazards model were used to compare survival.

RESULTS

Before risk stratification overall 2-year survival across the seven centres ranged from 60.2 to 85.3% (69.3-89.9%) after excluding early deaths) masking a range of survivals of 27.4% for the high-risk group with the worst survival to 100% in the low-risk group with the best survival. After excluding early deaths 2-year survival in the low risk groups (n=622) was greater than 90% in all centres. Multivariate analysis showed that the mortality risk increased four fold from low- to medium- and a further 1.6-fold from medium- to high-risk group. However, despite this adjustment for comorbidity and age there still remained a significant difference in survival among some centres, i.e. a 'centre effect' which ranked the centres.

CONCLUSION

Risk stratification diminishes the variance in survival between centres but a centre effect remains despite adjusting for age and comorbidity. Multicentre prospective studies are urgently required to identify the reasons for this apparent centre effect.

Death during the first 90 days of dialysis: a case control study

Comparison of survival data among centers may be used to assess performance, but may be influenced by the number of patients who die during the first 90 days of renal replacement therapy (RRT). Data published by registries in Europe do not detail these deaths, and US data generally exclude them from analysis for financial reasons. To study factors influencing such deaths we compared 42 patients who died within 90 days of first commencing RRT in one Scottish renal unit (group A) between 1971 and 1992 with 42 age- and sex-matched controls who started RRT over the same period and survived longer (group B). Patients who died within 90 days of RRT ranged in age from 25.3 to 83.7 years and had a mean age of 65.2 (SEM, 1.6; 95% confidence interval, 61.9 to 68.4). The proportion of patients who died during the first 90 days of RRT increased from 2% of all patients treated before 1981 to 12% in subsequent years. Thirty-three patients in group A received emergency dialysis via temporary venous access compared with only nine in group B (P < 0.055). There were more patients in group A with a diagnosis of arteriosclerotic renal artery stenosis (14 v 1) and with a history of smoking (15 v 2) than in group B (P < 0.0005). Median renal or nonrenal follow-up before RRT was 1.1 month in group A and 10.6 months in group B (P < 0.0001). Fewer patients in group A had no coexisting disease (1 v 17; P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic renal failure: factors influencing nephrology referral

Factors influencing referral of all 304 patients who developed persistent renal failure during one year were studied in the stable Grampian population. The annual incidence of chronic renal failure (CRF) (creatinine > or = 300 mumol/l) was 450/million of the population and of persistent advanced CRF (creatinine > or = 500 mumol/l), 132/million. After excluding those aged > 80 years and those with advanced malignancy, the corresponding incidence figures were 240/million/year and 81/million/year. Only 109 patients (35.8%) were referred to a nephrologist. Patients were divided according to age and coexisting disease into low, medium and high risk groups; 69% of CRF patients in the low, 58% in the medium, and 21% in the high risk group were referred (100%, 88% and 37%, respectively, of the patients with advanced CRF). Two-year patient survival in the low, medium and high risk groups was 100%, 63% and 27%, respectively, in referred patients, and 100%, 48% and 14%, respectively, in non-referred patients. This method of risk stratification identifies patients (particularly those with advanced CRF) likely to have a poor outcome irrespective of referral to a nephrologist. Earlier referral for interventions to delay the progress of the patients' renal and comorbid illnesses has considerable implications for future planning and funding of renal services.

Membranous nephropathy and granulomatous interstitial nephritis in sarcoidosis

A 56-year-old woman developed nephrotic syndrome in association with pulmonary sarcoidosis. Renal biopsy revealed both granulomatous interstitial nephritis and membranous nephropathy. Treatment with steroids resulted in a decrease in proteinuria and there was no deterioration in renal function over a subsequent period of 10 months. This case provides further evidence that secondary membranous nephropathy associated with sarcoidosis should be treated with steroids.