Biodiversity in urban habitat patches

We examined the biodiversity of urban habitats in Birmingham (England) using a combination of field surveys of plants and carabid beetles, genetic studies of four species of butterflies, modelling the anthropochorous nature of the floral communities and spatially explicit modelling of selected mammal species. The aim of the project was to: (i) understand the ecological characteristics of the biota of cities model, (ii) examine the effects of habitat fragment size and connectivity upon the ecological diversity and individual species distributions, (iii) predict biodiversity in cities, and (iv) analyse the extent to which the flora and fauna utilise the 'urban greenways' both as wildlife corridors and as habitats in their own right. The results suggest that cities provide habitats for rich and diverse range of plants and animals, which occur sometimes in unlikely recombinant communities. The studies on carabids and butterflies illustrated the relative importance of habitat quality on individual sites as opposed to site location within the conurbation. This suggests that dispersal for most of our urban species is not a limiting factor in population persistence, although elements of the woodland carabid fauna did appear to have some geographical structuring. Theoretical models suggested that dormice and water voles may depend on linear habitats for dispersal. The models also indicated that other groups, such as small and medium sized mammals, may use corridors, although field-based research did not provide any evidence to suggest that plants or invertebrates use urban greenways for dispersal. This finding indicates the importance of identifying a target species or group of species for urban greenways intended as dispersal routeways rather than as habitat in their own right. Their importance for most groups is rather that greenways provide a chain of different habitats permeating the urban environment. We suggest that planners can have a positive impact on urban biodiversity by slowing the pace of redevelopment and by not hurrying to tidy up and redevelop brownfield sites.

A novel end-effector design for robotics in image-guided needle procedures

BACKGROUND

Robotic end-effectors are being developed to facilitate image-guided minimally invasive needle-based procedures, such as tumour ablation, biopsy, thoracentesis and blood sampling.

METHODS

A novel mechanical end-effector was designed to address the challenges associated with any major needle-based procedure, focusing on liver biopsy and ablation. In this end-effector embodiment, the distal end of a single articulating arm can grip needles and instruments and allows a fairly high number of degrees of freedom of movement during the complex motions associated with positioning and driving needles, as well as the periodic motions associated with breathing patterns. Tightening a cable that runs through the articulations fixes the arm in a rigid state, allowing insertion of the gripped needle.

RESULTS

A design is presented that will require electro-mechanical stimulation and remote joystick control. The associated forces of cranial-caudal motion of soft tissue organs affects design constraints. A simulation study defined the process with tissue phantoms with mechanical properties in the range of hepatic tissue and the overlying abdominal wall. The robotic arm coupled with our end-effector could be deployed in an image-guided interventional suite.

CONCLUSIONS

Such a switch-able and flexible mode for a robotic arm could overcome much of the current limitations for automated needle placements for mobile targets, and could mitigate risks from breathing or patient motion with a rigid needle gripper in place.

Trends in fungal colonization of pancreatic necrosis in patients undergoing necrosectomy for acute pancreatitis

BACKGROUND

This study examines fungal colonization of post-inflammatory pancreatic necrosis in a cohort of patients undergoing open surgical necrosectomy in a single, tertiary referral unit over a 10-year period.

METHODS

The charts of all patients with acute pancreatitis who underwent surgical necrosectomy during the period January 1992 to December 2001 were examined. Following exclusions a population of 30 patients were identified. There were 18 men with a median (range) age of 42 (20-69) years. Sixteen (53%) underwent surgery because of positive fine needle aspirates and the remainder underwent surgery on clinical grounds. Twenty-nine (97%) received antibiotics prior to necrosectomy. Principal outcomes were the results of microbiological culture with reference to isolation of fungi, site of isolates, trends in colonization and outcome.

RESULTS

Candida were cultured from pancreatic necrosis in 5 (17%). These 5 individuals also had positive candidal cultures from sputum or bronchial aspirates. There were no deaths in patients with fungal colonization of necrosis. There was no change in the annual incidence of fungal colonization of necrosis over the study period.

CONCLUSION

Although this is a small study, there are two consistent observations: mortality in fungal colonization of necrosis was low and there was no change in the annual incidence of fungal colonization of necrosis over the decade. Discrepancies between these findings and those of previous reports mandate larger prospective evaluation.

Alternative cerebrospinal fluid tests to diagnose neurosyphilis in HIV-infected individuals

OBJECTIVE

To identify alternatives to the CSF-Venereal Disease Research Laboratory (VDRL) test for the diagnosis of neurosyphilis in HIV-infected individuals.

METHODS

CSF fluorescent treponemal antibody (FTA) reactivity and % CSF lymphocytes that were B cells in fresh and frozen samples were determined for 47 HIV-infected cases with syphilis and 26 HIV-infected controls. As for serum, CSF fluorescent treponemal antibody reactivity > or =2+ was considered positive. Based on the results in controls and cases with normal CSF measures, cut-offs for elevated CSF B cells were proposed to be > or =9% in fresh and > or =20% in frozen samples. Neurosyphilis was defined as a reactive CSF-VDRL.

RESULTS

CSF-FTA-ABS (absorbed) and CSF-FTA (unabsorbed and undiluted) were 100% sensitive for the diagnosis of neurosyphilis. Elevated % CSF B cells in fresh and cryopreserved samples was specific (100%) but not sensitive (40 and 43%) in post hoc analyses. The results of CSF-FTA and assessment of % CSF B cells together allowed 16% of cases with pleocytosis but nonreactive CSF-VDRL to be diagnosed with neurosyphilis and 26% to be diagnosed as not having neurosyphilis.

CONCLUSION

When the CSF-VDRL is nonreactive, CSF-FTA and % CSF B cells may help exclude or establish the diagnosis of neurosyphilis.

The biology and diagnostic applications of cadherins in neoplasia: a review

Cadherins are a large family of calcium-dependent "cell adhesion molecules". In addition to their structural role, cadherins have a number of important functions in the control of cell growth and differentiation. This paper reviews the biology of cadherins and their role in neoplastic transformation, development of the invasive and metastatic phenotype, effects on tumour morphology and the applications of cadherin immunolabelling in tumour diagnosis. Potential areas of future investigation and diagnostic applications are discussed.

Membranoproliferative glomerulonephritis associated with low-grade B cell lymphoma presenting in the kidney

Low-grade B cell lymphoma of mucosa-associated tissue type (MALToma) rarely may involve the kidney. Membranoproliferative glomerulonephritis (MPGN) is an uncommon complication of B cell lymphoma and may be related to cryoglobulin and/or immunoglobulin synthesis by a secretory B cell clone. We report 2 patients with the novel renal biopsy findings of coexistent MALToma and MPGN. Both subjects presented with nephrotic proteinuria and renal insufficiency. One patient had a serum M protein (IgG K) but neither individual had any other clinical or serologic evidence of systemic disease, including hematolymphoid malignancy, autoimmune disease, cryoglobulinemia, or hepatitis C viral infection. Both renal biopsies demonstrated MPGN type I with immunoglobulin deposits that in 1 case showed light chain restriction (IgM K). Electron microscopy disclosed corresponding glomerular electron dense deposits in subendothelial locations. Both biopsies also contained atypical interstitial lymphoid infiltrates comprising marginal zone (centro-cyte-like) cells that infiltrated tubules and showed extra-capsular extension. Immunostains demonstrated a predominantly B cell population that lacked expression of CD5 and cycline D1, and gene rearrangement studies confirmed the presence of a monoclonal B cell population in both cases. These findings indicate that low-grade B cell lymphoma in the kidney may be an unexpected finding in patients with nephrotic syndrome related to MPGN. Immunophenotypic and gene rearrangement studies are important ancillary tools for the evaluation of atypical lymphoid infiltrates in kidney biopsies.

Soft-tissue anatomy of the extant hominoids: a review and phylogenetic analysis

This paper reports the results of a literature search for information about the soft-tissue anatomy of the extant non-human hominoid genera, Pan, Gorilla, Pongo and Hylobates, together with the results of a phylogenetic analysis of these data plus comparable data for Homo. Information on the four extant non-human hominoid genera was located for 240 out of the 1783 soft-tissue structures listed in the Nomina Anatomica. Numerically these data are biased so that information about some systems (e.g. muscles) and some regions (e.g. the forelimb) are over-represented, whereas other systems and regions (e.g. the veins and the lymphatics of the vascular system, the head region) are either under-represented or not represented at all. Screening to ensure that the data were suitable for use in a phylogenetic analysis reduced the number of eligible soft-tissue structures to 171. These data, together with comparable data for modern humans, were converted into discontinuous character states suitable for phylogenetic analysis and then used to construct a taxon-by-character matrix. This matrix was used in two tests of the hypothesis that soft-tissue characters can be relied upon to reconstruct hominoid phylogenetic relationships. In the first, parsimony analysis was used to identify cladograms requiring the smallest number of character state changes. In the second, the phylogenetic bootstrap was used to determine the confidence intervals of the most parsimonious clades. The parsimony analysis yielded a single most parsimonious cladogram that matched the molecular cladogram. Similarly the bootstrap analysis yielded clades that were compatible with the molecular cladogram; a (Homo, Pan) clade was supported by 95% of the replicates, and a (Gorilla, Pan, Homo) clade by 96%. These are the first hominoid morphological data to provide statistically significant support for the clades favoured by the molecular evidence.

Thymic size on chest radiograph and rapid disease progression in human immunodeficiency virus 1-infected children

BACKGROUND

Early infection of the thymus, an organ central to the ontogeny of the immune system, has been proposed as a cause of rapid progression in pediatric HIV disease.

OBJECTIVE

To test the hypothesis that small thymic volume is associated with rapid disease progression in HIV-infected children.

DESIGN

Three pediatric radiologists established criteria for rating the size of the thymic profile on chest radiographs. All available baseline chest radiographs were reviewed in a random sequence, with radiologists blinded to study subjects' clinical status. A consensus was reached on whether the thymus was normal or small for age.

SETTING

A prospective multicenter study of the natural history of HIV-1 infection in children, the Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted Human Immunodeficiency Virus Infection (P2C2) Study.

PATIENTS

Fifty-eight HIV-infected children and 38 control children (uninfected but born to HIV-infected women) for whom chest radiographs in the first year of life were available.

MAIN OUTCOME MEASURE

Rapid progression of HIV disease, defined as CDC Clinical Category C (severely symptomatic) or Immunologic Category 3 (severe immunosuppression) by 1 year of age.

RESULTS

The mean age at the time of chest radiography was 3.5 months. Ten (17%) HIV-infected children had reduced thymic profile size, whereas no controls did (P = 0.006). Of the 58 (59%) HIV-infected children 34 were classified as rapid progressors, and 9 (26%) of them had reduced thymus size, compared with 1 (4%) of the non-rapid progressor children [odds ratio, 8.28; 95% confidence interval (CI), 1.0, 70.5; P = 0.035]. Baseline mean CD4+ count was 1642 (95% CI 1322 to 2009) cells/microl for those with normal thymus and 740 (95% CI 380 to 1275) cells/microl for those with reduced thymus (P = 0.007).

CONCLUSION

Early thymic involution is associated with rapidly progressive disease in HIV-infected children.

A comparison of CAL with a conventional method of delivery of cell biology to undergraduate nursing students using an experimental design

This paper describes the development and evaluation of a series of computer assisted learning (CAL) packages on cell biology produced for an undergraduate nursing course. The CAL packages were based on the material originally delivered in Kindermann's slide practical classes. The decision to convert this teaching material into CAL packages was taken for a number of reasons, but mainly in response to student evaluations and lack of equipment and staff resources needed to adequately deliver the sessions. Student feedback showed that CAL was preferred to the slide classes. Two studies were carried out to compare the CAL method of delivery with the conventional method using an experimental design. Students taught using CAL felt more confident that they would be able to use the material they had learnt if required as a basis for future work. The distributions rating 'how necessary was the contribution of a teacher in the session' were skewed towards the 'essential' end of the scale for the slide group but towards the 'unnecessary' end for the CAL group. Learning effectiveness was not compromised by the introduction of CAL, even though this meant that no lecturer was on hand to deal with questions.

Craniodental variation in Paranthropus boisei: a developmental and functional perspective

What levels and patterns of craniodental variation among a fossil hypodigm are necessary to reject the null hypothesis that only a single species is sampled? We suggest how developmental and functional criteria can be used to predict where in the skeleton of fossil hominins we should expect more, or less, within-species variation. We present and test three hypotheses about the factors contributing to craniodental variation in extant primate taxa, and then apply these results to the interpretation of the P. boisei hypodigm. Within the comparative samples of extant Homo, Pan, Gorilla, Pongo, and Colobus, variables from the cranial base, neurocranium, and face that are not subject to high magnitudes of strain have consistently lower levels of intraspecific variation than variables from regions of the face subject to high levels of strain. Dental size variables are intermediate in terms of their reliability. P. boisei is found to have a low degree of variability relative to extant primates for variables shown to be generally useful for testing taxonomic hypotheses. Contrary to the claims of Suwa et al. ([1997] Nature 389:489-492), the recently discovered material from Konso falls within the range of variation of the "pre-Konso" hypodigm of P. boisei for available conventional metrical variables. Those aspects of the Konso material that appear to extend the range of the P. boisei hypodigm involve regions of the skull predicted to be prone to high levels of within-species variation. The approach used in this study focuses on craniodental data, but it is applicable to other regions of the skeleton.

Homoplasy and the early hominid masticatory system: inferences from analyses of extant hominoids and papionins

Early hominid masticatory characters are widely considered to be more prone to homoplasy than characters from other regions of the early hominid skull and therefore less reliable for phylogenetic reconstruction. This hypothesis has important implications for current reconstructions of early hominid phylogeny, but it has never been tested. In this paper we evaluate the likely veracity of the hypothesis using craniometric data from extant primate groups for which reliable consensus molecular phylogenies are available. Datasets representing the extant large-bodied hominoid genera and the extant papionin genera were compiled from standard measurements. The data were adjusted to minimise the confounding effects of body size, and then converted into discrete character states using divergence coding. Each dataset was divided into four regional character groups: (1) palate and upper dentition, (2) mandible and lower dentition, (3) face and (4) cranial vault and base. Thereafter, the regional character groups were analysed using cladistic methods and the resulting phylogenetic hypotheses judged against the consensus molecular phylogenies for the hominoids and papionins. The analyses indicated that the regions dominated by masticatory characters-the palate and upper dentition, and the mandible and lower dentition-are no less reliable for phylogenetic reconstruction than the other regions of the skull. The four regions were equally affected by homoplasy and were, therefore, equally unreliable for phylogenetic reconstruction. This finding challenges the recent suggestion that Paranthropus is polyphyletic, which is based on the assumption that masticatory characters are especially prone to homoplasy. Our finding also suggests that, contrary to current practice, there is no a priori reason to de-emphasise the phylogenetic significance of the masticatory similarities between Homo rudolfensis and the australopiths. The corollary of this is that H. rudolfensis is unlikely to be a member of the Homo clade and should therefore be allocated to another genus.

A logit model for the effect of telecardiology on acute newborn transfers

The deregionalization of neonatal intensive care in the United States has shifted the site of care for many newborn infants away from academic medical centers where subspecialty support is available.

OBJECTIVE

To investigate the effect of immediate echocardiogram interpretation via telemedicine on rates of neonatal transfer to academic medical centers.

METHODS

A logit model was developed to predict the probability of transfer from two regional level 3 neonatal intensive care units to academic medical centers. One of these units implemented a telecardiology program and the other acted as a comparison institution with on-site cardiology expertise. The telecardiology intervention began 18 months into the 36-month study period.

SUBJECTS

Infants (n = 2,142) admitted to neonatal intensive care at either of the two institutions during calendar years 1994 through 1996.

RESULTS

A statistically significant reduction in the rate of transfer to academic medical centers was observed. Telecardiology was associated with a 58% reduction of such transfers (p = .001, 95% CI = 30%, 75%). No such reduction was noted at the comparison institution. It is estimated that approximately 30 transfers were eliminated during the study period, resulting in the elimination of approximately $150,000 in hospital charges. In addition, the infants that were transferred after the adoption of telemedicine were more often transferred to their telemedicine partner institution (p < .02).

Chronic radiographic lung changes in children with vertically transmitted HIV-1 infection

OBJECTIVE

We prospectively studied children with and without maternally transmitted HIV-1 infection born to mothers infected with HIV-1 to determine the incidence of chronic radiographic lung changes (CRC) and to correlate these changes with clinical assessments.

SUBJECTS AND METHODS

Between 1990 and 1997, we scored 3050 chest radiographs using a standardized form. Group I children (n = 201) were HIV-1-infected at enrollment. Group II children (n = 512) were enrolled prenatally or before 28 days postpartum and subsequently subdivided into group IIa (n = 86), children identified as HIV-1-infected; and group IIb (n = 426), those who were HIV-1-uninfected. CRC were defined as parenchymal consolidations or nodular disease lasting 3 months or more or increased bronchovascular markings or reticular densities lasting 6 months or more. Morbidity was assessed by CD4 counts, viral load, the presence of low oxygen saturation, wheezing, tachypnea, crackles, and clubbing.

RESULTS

The cumulative incidence of chronic radiographic lung changes in HIV-1-infected children was 32.8% by 4 years old, with increased bronchovascular markings or reticular densities being most common. Chronic changes were associated with lower CD4 cell counts and higher viral loads. Resolution of these chronic changes was associated with decreasing CD4 cell counts but not with lower rates of clinical findings, viral load, or difference in survival.

CONCLUSION

With increased survival, CRC are becoming more common. The resolution of these changes may indicate immunologic deterioration rather than clinical improvement.