Increase in nephrology advanced trainee numbers in Australia and associated reduction in clinical exposure over the past decade.

BACKGROUND: Advanced training in nephrology should provide broad experience in all aspects of nephrology. In Australia, the Specialist Advisory Committee in Nephrology oversees nephrology training, and recent increases in advanced trainee numbers have led to concern about dilution of training experience. No study has examined variations in clinical exposure for nephrology trainees in Australia. AIM: To assess the changes in nephrology advanced training in Australia with respect to trainee numbers and exposure to patients and procedures over the past 10 years. METHODS: A retrospective study was performed by obtaining all available Royal Australasian College of Physician supervisor reports from 2000 to 2010 to determine differences in clinical exposure and procedures performed by nephrology trainees. RESULTS: Five hundred and forty-two reports were reviewed involving 208 nephrology trainees in Australia across 53 different training sites. In 2000, 22 trainees were undertaking a core clinical year of training. Trainee numbers have steadily risen from 33 in 2004 to 84 in 2010. The greatest increases have occurred in New South Wales, Victoria and Queensland (sixfold, threefold and fivefold increases respectively). Trainee exposure to dialysis patients has gradually decreased in the past decade. The average number per trainee per year in 2000 compared with 2010 were 66 versus 43 (P = 0.02) and 28 versus 16 (P = 0.01) for haemodialysis and peritoneal dialysis respectively. Acute kidney injury cases per trainee showed a gradual nonsignificant reduction over time and average procedural numbers per trainee decreased significantly from 2000 to 2010 with fewer temporary dialysis catheters inserted per year (39 vs 10, P < 0.01) and fewer renal biopsies performed per year (65 vs 41, P < 0.01). The proportion of trainees working in a hospital that does not provide exposure to acute transplantation has steadily increased from 15% in 2003 to 44% in 2010. CONCLUSIONS: There has been a dramatic and significant increase in nephrology advanced trainee numbers over the past decade at a more rapid rate than the growth in dialysis and transplant patient numbers. This study suggests that training experience has diminished over the past decade and supports a 3-year core clinical nephrology training programme in Australia.

Rothia aeria vertebral discitis/osteomyelitis in an immunocompetent adult: Case report and literature review.

Rothia aeria is a gram-positive, pleomorphic bacteria forming part of human oral microflora usually only causing periodontal and dental infections. We describe the case of a 68-year-old immunocompetent male with lumbar vertebral discitis/osteomyelitis caused by R. aeria. A review of the literature demonstrated seventeen cases of non-dental R. aeria infection of which only six were in immunocompetent individuals. This is the first reported case of R. aeria vertebral discitis/osteomyelitis.

The structure of microtubule-motor complexes.

New images, calculated from electron micrographs, show the three-dimensional structures of microtubules and tubulin sheets decorated stoichiometrically with globular motor protein domains (heads). Single heads of kinesin and ncd, the kinesin-related protein that moves in the reverse direction to kinesin, bind in the same way to the same site on tubulin. Dimeric kinesin and dimeric ncd show an interesting difference in the positions of their second heads.

The microtubule lattice--20 years on.

In 1974, optical diffraction and image analysis indicated that tubulin dimers in the cylindrically complete A-tubule of flagellar doublet microtubules are arranged with helical symmetry, while those in the incomplete B-tubule associate differently. Recently, electron micrographs of reassembled brain microtubules decorated with kinesin heads have shown that the tubulin dimers there are arranged as in the B-tubule. The lack of symmetry of microtubules assembled in vitro prompts Linda Amos to speculate here that the assembly process in vitro may differ from that occurring in the cell.

Arrangement of high molecular weight associated proteins on purified mammalian brain microtubules.

The arrangement of the high molecular weight proteins associated with the walls of reconstituted mammalian brain microtubules has been investigated by electron microscopy of negatively stained preparations. The images are found to be consistent with an arrangement whereby the high molecular weight molecules are spaced 12 tubulin dimers apart, i.e., 960 A, along each protofilament of the microtubule, in agreement with the relative stoichiometry of tubulin and high molecular weight protein. Molecules on neighbouring protofilaments seem to be staggered so that they give rise to a helical superlattice, which can be superimposed on the underlying tubulin lattice. In micrographs of disintegrating tubules there is some indication of lateral interactions between neighbouring high molecular weight molecules. When the microtubules are depolymerized into a mixture of short spirals and rings, the high molecular weight proteins appear to remain attached to their respective protofilaments.

Localization of tektin filaments in microtubules of sea urchin sperm flagella by immunoelectron microscopy.

Extraction of doublet microtubules from the sperm flagella of the sea urchin Strongylocentrotus purpuratus with sarkosyl (0.5%)-urea (2.5 M) yields a highly pure preparation of "tektin" filaments that we have previously shown to resemble intermediate filament proteins. They form filaments 2-3 nm in diameter as seen by negative stain electron microscopy and are composed of approximately equal amounts of three polypeptide bands with apparent molecular weights of 47,000, 51,000, and 55,000, as determined by SDS PAGE. We prepared antibodies to this set of proteins to localize them in the doublet microtubules of S. purpuratus and other species. Tektins and tubulin were antigenically distinct when tested by immunoblotting with affinity-purified antitektin and antitubulin antibodies. Fixed sperm or axonemes from several different species of sea urchin showed immunofluorescent staining with antitektin antibodies. We also used antibodies coupled to gold spheres to localize the proteins by electron microscopy. Whereas a monoclonal antitubulin (Kilmartin, J.V., B. Wright, and C. Milstein, 1982, J. Cell Biol. 93:576-582) decorates intact microtubules along their lengths, antitektins labeled only the ends of intact microtubules and sarkosyl-insoluble ribbons. However, if microtubules and ribbons attached to electron microscope grids were first extracted with sarkosyl-urea, the tektin filaments that remain were decorated by antitektin antibodies throughout their length. These results suggest that tektins form integral filaments of flagellar microtubule walls, whose antigenic sites are normally masked, perhaps by the presence of tubulin around them.

Health policy and the coloring of an American male crisis: a perspective on community-based health services.

Health services at the community level are organized and financed in such a way that men need access but encounter barriers to care such as poor service design, lack of insurance, and the absence of health literacy. Community health delivery systems may not be appropriate, effective, fit, or able to meet the needs they are charged to fill. Community-based health services, including health departments, are underfunded, understaffed, and unable to carry out their mission in a way that protects the health of the community. The current design for funding and delivering health care services excludes poor men, particularly men of color. Improving the health of men requires modifications in the way health care is financed, delivered, and managed.

Focusing-in on microtubules.

A good approximation of the atomic structure of a microtubule has been derived from docking the high-resolution structure of tubulin, solved by electron crystallography, into lower resolution maps of whole microtubules. Some structural interactions with other molecules, including nucleotides, drugs, motor proteins and microtubule-associated proteins, can now be predicted.

Structure and dynamics of molecular motors.

The structures of the oppositely directed microtubule motors kinesin and ncd have been solved to atomic resolution. The two structures are very similar and are also homologous to myosin. Myosins and kinesins differ kinetically but, tantalizingly, cryoelectron microscopy has recently revealed that both structures may tilt during ADP release. Such evidence suggests that the two motor families use common structural mechanisms.

Congruent docking of dimeric kinesin and ncd into three-dimensional electron cryomicroscopy maps of microtubule-motor ADP complexes.

We present a new map showing dimeric kinesin bound to microtubules in the presence of ADP that was obtained by electron cryomicroscopy and image reconstruction. The directly bound monomer (first head) shows a different conformation from one in the more tightly bound empty state. This change in the first head is amplified as a movement of the second (tethered) head, which tilts upward. The atomic coordinates of kinesin.ADP dock into our map so that the tethered head associates with the bound head as in the kinesin dimer structure seen by x-ray crystallography. The new docking orientation avoids problems associated with previous predictions; it puts residues implicated by proteolysis-protection and mutagenesis studies near the microtubule but does not lead to steric interference between the coiled-coil tail and the microtubule surface. The observed conformational changes in the tightly bound states would probably bring some important residues closer to tubulin. As expected from the homology with kinesin, the atomic coordinates of nonclaret disjunctional protein (ncd).ADP dock in the same orientation into the attached head in a map of microtubules decorated with dimeric ncd.ADP. Our results support the idea that the observed direct interaction between the two heads is important at some stages of the mechanism by which kinesin moves processively along microtubules.

Body size of Papua New Guineans: a comparison of the body mass index of adults in selected urban and rural areas of Papua New Guinea.

This is a cross-sectional study conducted in Port Moresby and 3 rural areas of Papua New Guinea from 1999 to 2002. These areas were selected because of their specific characteristics such as modernity, geographical location and remoteness. The aim of the study was to compare the body mass index (BMI) of selected urban and rural populations. When age was standardized, in urban and periurban populations, the mean BMI increased with age to about 40 years, plateaued and then decreased in older age. The BMI was higher in Port Moresby than in the other study areas: many people in Port Moresby were overweight (40%) and obese (21%), and by gender, 26% of females and 16% of males were obese. In Manus, the prevalence of overweight and obesity was 36% and 18% respectively. In both Port Moresby and Manus, more women than men were obese. Obesity was not a problem in rural areas of Strickland and Central Province. In rural Central Province 52% of subjects had a BMI < 20 kg/m2. Obesity is becoming a public health problem in the urban areas. The high prevalence of overweight and obesity corresponds with the high intake of refined carbohydrates and fatty foods in urban and periurban areas. It will be necessary to carry out health awareness and education on the risk factors associated with obesity in the urban and periurban areas and promote healthy environments: healthy foods should be available and affordable, and the accessibility and safety of exercise and walking tracks must be supported by the community and government agencies.

The use of seatbelts in Port Moresby 12 years after the seatbelt legislation in Papua New Guinea.

The aim of this study was to assess the rate of seatbelt use by drivers and front-seat passengers in Port Moresby, 12 years after the seatbelt legislation in 1993. Before the legislation, the rate of seatbelt usage was only 13.3% for drivers and 11.4% for front-seat passengers. Use of seatbelts was assessed by observers at the main city roundabout. 50% of male drivers, 78% of female drivers, 49% of Papua New Guinean drivers and 69% of expatriate drivers wore seatbelts. Among the young drivers (teenagers aged < 20 years) 55% wore seatbelts. Of the front-seat passengers, 37% of males and 58% of females wore seatbelts. Female drivers and female front-seat passengers were more likely to wear seatbelts than males (OR 2.55 [95% CI 1.53-4.23] and 2.34 [95% CI 1.32-4.14]). The front-seat passengers were more likely to be wearing seatbelts if the drivers wore theirs (OR 2.70 [95% CI 1.60-4.55]). Proportionately more drivers and front-seat passengers were wearing seatbelts than during the pre-legislation period, but more seatbelt education and awareness is needed because of the increasing number of road traffic accidents in Papua New Guinea.

Bacterial ancestry of actin and tubulin.

The structural and functional resemblance between the bacterial cell-division protein FtsZ and eukaryotic tubulin was the first indication that the eukaryotic cytoskeleton may have a prokaryotic origin. The bacterial ancestry is made even more obvious by the findings that the bacterial cell-shape-determining proteins Mreb and Mbl form large spirals inside non-spherical cells, and that MreB polymerises in vitro into protofilaments very similar to actin. Recent advances in research on two proteins involved in prokaryotic cytokinesis and cell shape determination that have similar properties to the key components of the eukaryotic cytoskeleton are discussed.

Community screening for high blood pressure among adults in urban and rural Papua New Guinea.

This is a cross-sectional study conducted intermittently in Port Moresby, the National Capital District of Papua New Guinea, from 1996 to 1997; Mt Obree in Central Province in October 2000; Upper Strickland River in April 2001; and the Balopa Islands in Manus Province in December 2002. The aim of the study was to determine the prevalence of high blood pressure and identify possible risk factors for hypertension in the 'healthy' population in Port Moresby and the three rural communities. There were 1491 subjects surveyed, 704 males and 787 females. Their ages ranged from 20 to 84 years. Just over 6% of subjects were aged 65 years and above. There were 205 (14%) smokers and 340 (23%) betelnut chewers. The Central (rural) subjects were generally younger with the lowest mean systolic and diastolic blood pressures and lowest body mass index (BMI) in both males and females (no overweight or obesity). In Central and Strickland the mean systolic (SBP) and diastolic (DBP) blood pressures were lower and remained the same in all age groups, then in females decreased with age after 55 years. The Manus (rural) subjects were older with higher mean systolic and diastolic blood pressures and higher mean BMI, surprisingly similar to the urban population of Port Moresby. The mean systolic blood pressures in Port Moresby and Manus increased with age in both sexes, while the mean diastolic pressure remained the same in all age groups in females and decreased after the age of 50 years. The prevalence of systolic hypertension among men and women was higher in Manus than in urban Port Moresby and, among the female subjects, Manus had the highest at 31%, while Central recorded the lowest for both males and females. The mean systolic blood pressures of betelnut chewers in Port Moresby, Manus and Central were lower (by 1-9 mmHg) but higher--in males only--in Strickland. The mean diastolic blood pressures of betelnut chewers were lower in all study sites. Both high BMI (overweight and obesity) and older age were significantly associated with high systolic blood pressure but betelnut chewing was significantly associated with lower mean SBP (p < 0.001), a protective effect against systolic hypertension.

Retinal disease in the C3 glomerulopathies and the risk of impaired vision.

BACKGROUND: Dense deposit disease and atypical hemolytic uremic syndrome are often caused by Complement Factor H (CFH) mutations. This study describes the retinal abnormalities in dense deposit disease and, for the first time, atypical haemolytic uremic syndrome. It also reviews our understanding of drusen pathogenesis and their relevance for glomerular disease. METHODS: Six individuals with dense deposit disease and one with atypical haemolytic uremic syndrome were studied from 2 to 40 years after presentation. Five had renal transplants. All four who had genetic testing had CFH mutations. Individuals underwent ophthalmological review and retinal photography, and in some cases, optical coherence tomography, and further tests of retinal function. RESULTS: All subjects with dense deposit disease had impaired night vision and retinal drusen or whitish-yellow deposits. Retinal atrophy, pigmentation, and hemorrhage were common. In late disease, peripheral vision was restricted, central vision was distorted, and there were scotoma from sub-retinal choroidal neovascular membranes and atypical serous retinopathy. Drusen were present but less prominent in the young person with atypical uremic syndrome due to a heterozygous CFH mutation. CONCLUSIONS: Drusen are common in forms of C3 glomerulopathy caused by compound heterozygous or heterozygous CFH mutations. They are useful diagnostically but also impair vision. Drusen have an identical composition to glomerular deposits. They are also identical to the drusen of age-related macular degeneration, and may respond to the same treatments. Individuals with a C3 glomerulopathy should be assessed ophthalmologically at diagnosis, and monitored regularly for vision-threatening complications.

Kinesin light chain isoforms in Caenorhabditis elegans.

cDNAs for two isoforms of kinesin light chain in Caenorhabditis elegans have been cloned and sequenced; the deduced M(r) values of the polypeptides are 60,338 and 58,938. Surprisingly, two independent cDNA libraries, each derived from worms at mixed stages of development, provided different single isoforms. The two isoforms are apparently derived from a single gene but have differences at both N and C termini of the predicted protein sequences. The sequences are highly homologous to those from other species, except for some minor features that may be related to the shortened form of the kinesin heavy chain, the product of gene unc-116, with which the light chains are assumed to associate.

Antibodies to cytoplasmic dynein heavy chain map the surface and inhibit motility.

Polyclonal antibodies have been raised against four 16 residue peptides with sequences taken from the C-terminal quarter of the human cytoplasmic dynein heavy chain. The sites are downstream from a known microtubule-binding domain associated with the "stalk" that protrudes from the motor domain. The antisera were assayed using bacterially expressed proteins with amino acid sequences taken from the human cytoplasmic dynein heavy chain. Every antiserum reacted specifically with the appropriate expressed protein and with pig brain cytoplasmic dynein, whether the protein molecules were denatured on Western blots or were in a folded state. But, whereas three of the four antisera recognized freshly purified cytoplasmic dynein, the fourth reacted only with dynein that had been allowed to denature a little. After affinity purification against the expressed domains, whole IgG molecules and Fab fragments were assayed for their effect on dynein activity in in vitro microtubule-sliding assays. Of the three anti-peptides that reacted with fresh dynein, one inhibited motility but the others did not. The way these peptides are exposed on the surface is compatible with a model whereby the dynein motor domain is constructed from a ring of AAA protein modules, with the C-terminal module positioned on the surface that interacts with microtubules. We have tentatively identified an additional AAA module in the dynein heavy chain sequence, which would be consistent with a heptameric ring.

Re-examination of the polarity of microtubules and sheets decorated with kinesin motor domain.

Electron microscope images of microtubules and tubulin sheets decorated with kinesin head domains have shown the main mass of the kinesin head domain to be superimposed on one subunit of each tubulin dimer. We have polymerized brain tubulin extensions on to the ends of flagellar axonemes under varied conditions, in order to check the polarity of the tubulin-kinesin head complex. Since the polarity of axonemes incubated with normal brain tubulin may be ambiguous, we also tried 50% N-ethylmaleimide-treated tubulin which specifically blocks minus ends. Our conclusion, which conflicts with recently published results, is that the main mass of the kinesin head is associated with the tubulin subunit closer to the plus end of a microtubule.

Nucleotide-dependent structural changes in dimeric NCD molecules complexed to microtubules.

Complexes consisting of motor domains of the kinesin-like protein ncd bound to reassembled brain microtubules were visualised using cryoelectron microscopy and helical image reconstruction. Different nucleotide-associated states of a dimeric construct (NDelta295-700) of ncd were analysed to reveal ADP-containing, AMP.PNP-containing and empty (rigor) conformations. In these three states, each thought to mimic a different stage in ATP turnover, the double-headed motors attach to the microtubules by one head only, with the free head tethered in relatively fixed positions. The three structures differ both in the way the attached heads interact with tubulin and in the position of the tethered heads. In the strongly binding rigor and AMP.PNP (ATP-like) states, the attached head makes close contact with both subunits of a tubulin heterodimer. In the weakly bound ADP state, the contact made by the attached head with the monomer closer to the plus end appears to be more loose. Also, in the ATP-like state, the free head tilts nearer to the plus end than in the other two states. The data argue against model mechanisms in which a conformational change in the bound head guides the free head closer to its next binding site; on the contrary, the transition from ADP-filled via rigor to the AMP.PNP (ATP-like) state of the bound head produces a small motion of the free head in the counter-productive direction. However, the observation that the tethered head points towards the minus end, in all three states, is consistent with the idea that the relative arrangement of the heads in a dimer is a major determinant of directionality.