Insights into the formation and diversification of a novel chiropteran wing membrane from embryonic development

BACKGROUND

Through the evolution of novel wing structures, bats (Order Chiroptera) became the only mammalian group to achieve powered flight. This achievement preceded the massive adaptive radiation of bats into diverse ecological niches. We investigate some of the developmental processes that underlie the origin and subsequent diversification of one of the novel membranes of the bat wing: the plagiopatagium, which connects the fore- and hind limb in all bat species.

RESULTS

Our results suggest that the plagiopatagium initially arises through novel outgrowths from the body flank that subsequently merge with the limbs to generate the wing airfoil. Our findings further suggest that this merging process, which is highly conserved across bats, occurs through modulation of the programs controlling the development of the periderm of the epidermal epithelium. Finally, our results suggest that the shape of the plagiopatagium begins to diversify in bats only after this merging has occurred.

CONCLUSIONS

This study demonstrates how focusing on the evolution of cellular processes can inform an understanding of the developmental factors shaping the evolution of novel, highly adaptive structures.

Length of exposure to high post-rigor temperatures affects the tenderisation of the beef M. longissmus dorsi

This experiment examined the effect of length of exposure of bovine M. longissmus dorsi to high temperatures (37°C) on proteolytic activity during post-mortem aging and subsequent meat tenderness. To avoid confounding between pH decline and incubation treatments, the experiment was conducted on post-rigor meat (pH < 5.6), which had entered rigor at 15°C. This meat was first incubated at 15°C until rigor (pH < 5.6), whereupon samples were then reheated and maintained at 37°C for 0, 1 or 3 h. Following incubation, samples were aged at 1°C for 1–21 days. Control groups were incubated at either 15 or 37°C until pH < 5.6, followed by aging at 1°C. High rigor temperatures accelerated post-mortem proteolysis early in the post-mortem period, as indicated by a rapid decline in shear force (P < 0.01), but post-mortem aging ceased at about day 3 post-mortem and the high rigor temperature treatment was ultimately 30% tougher at day 21 post-mortem (P < 0.01). The process of reheating samples from 15 to 37°C had minimal effect on tenderness levels, but was associated with a slight increase in proteolysis, identified by myofibril length, and was associated with an increase in cook loss percentage (P < 0.05). Shear force in the length of exposure experiment was affected by an incubation time × post-mortem aging interaction (P < 0.01). This indicated an initial acceleration of post-mortem aging with increased length of exposure, but also a reduction in the ultimate tenderness of product after extended post-mortem aging. This was presumably due to the loss of proteolytic enzyme activity caused by the instability of proteolytic enzymes at high ionic strength conditions such as those present in post-mortem muscle.

Musculoskeletal ultrasound - used to best advantage

BACKGROUND

Effective management of both acute and chronic musculoskeletal pain revolves around a good history and physical examination, as well as a more detailed knowledge of anatomy than is required in other related medical disciplines. Imaging - if indicated - should not be looked upon as the panacea for problem solving but needs to be considered in the light of what a particular modality is best designed to do.

OBJECTIVE

In the practice of cost effective medicine, a specific imaging modality must be chosen on the basis that it is the best economically to provide the information sought which in turn allows the formulation of an appropriate management plan.

DISCUSSION

Ultrasound imaging has many advantages over other modalities for assessing musculoskeletal dysfunction. The major advantages are no radiation, 'real time' allows visualisation of functioning tissue, and it is the gold standard for assessing tendons. The most expensive or latest imaging modality is not always the most appropriate.

Automated apparatus for quantitation of social approach behaviors in mice

Mouse models of social dysfunction, designed to investigate the complex genetics of social behaviors, require an objective methodology for scoring social interactions relevant to human disease symptoms. Here we describe an automated, three chambered apparatus designed to monitor social interaction in the mouse. Time spent in each chamber and the number of entries are scored automatically by a system detecting photocell beam breaks. When tested with the automated equipment, juvenile male C57BL/6J mice spent more time in a chamber containing a stranger mouse than in an empty chamber (sociability), similar to results obtained by the observer scored method. In addition, automated scoring detected a preference to spend more time with an unfamiliar stranger than a more familiar conspecific (preference for social novelty), similar to results obtained by the observer scored method. Sniffing directed at the wire cage containing the stranger mouse correlated significantly with time spent in that chamber, indicating that duration in a chamber represents true social approach behavior. Number of entries between chambers did not correlate with duration of time spent in the chambers; entries instead proved a useful control measure of general activity. The most significant social approach behavior took place in the first five minutes of both the sociability and preference for social novelty tests. Application of these methods to C57BL/6J, DBA/2J and FVB/NJ adult males revealed that all three strains displayed tendencies for sociability and preference for social novelty. To evaluate the importance of the strain of the stranger mouse on sociability and preference for social novelty, C57BL/6J subject mice were tested either with A/J strangers or with C57BL/6J strangers. Sociability and preference for social novelty were similar with both stranger strains. The automated equipment provides an accurate and objective approach to measuring social tendencies in mice. Its use may allow higher-throughput scoring of mouse social behaviors in mouse models of social dysfunction.

Development of mental health services in Tanzania: a reappraisal for the future

The article traces the historical development of mental health services in Tanzania from traditional practices through custodial institutions during the colonial period, efforts towards decentralization, including the development of innovative agricultural rehabilitation villages during the 60s and the introduction of primary mental health care during the 80s right up to the present. Available resources in Tanzania, including the traditional healing system, the family and ample arable land were examined as to how these might be used in the care of mental patients and the promotion of mental health in general. The article points to real opportunities and a possible course of action for the future.

Hospital outbreak of Klebsiella pneumoniae resistant to broad-spectrum cephalosporins and beta-lactam-beta-lactamase inhibitor combinations by hyperproduction of SHV-5 beta-lactamase

An aminoglycoside- and ceftazidime-resistant strain of Klebsiella pneumoniae K2 producing the extended-spectrum beta-lactamase SHV-5 infected or colonized 14 pediatric patients at Guy's Hospital. The patients were mostly neonates recovering from cardiac surgery for congenital defects. The organism was also isolated from a nurse and from the father of one of the children. Four patients had septicemia, and two septicemic neonates with postoperative renal failure died. Aminoglycoside and cephalosporin resistance transferred to Escherichia coli in vitro on a 160-kb plasmid, and a similar resistant E. coli strain was isolated from the stools of one of the affected children. The epidemic organism colonized the bowel and skin and was probably transmitted via staff hands. Five wards were involved because of extensive patient movements. The outbreak was controlled by patient isolation and attention to handwashing. All of the isolates of the outbreak strain were identical by phage typing, ribotyping, plasmid profiling, and biochemical and serological testing, but they varied in their production of SHV-5. Some isolates produced normal amounts of SHV-5 and were susceptible to beta-lactam-beta-lactamase inhibitor combinations. Others, including the single isolate of multiresistant E. coli, produced up to five times as much enzyme as "normal" isolates. This hyperproduction resulted in increased resistance to several penicillins and cephalosporins and to the beta-lactam-beta-lactamase inhibitor combinations amoxicillin-clavulanic acid, ampicillin-sulbactam, piperacillin-tazobactam, and ceftazidime-clavulanic acid. The hyperproduction of SHV-5 by K. pneumoniae and E. coli seen in this outbreak suggests that beta-lactam-beta-lactamase inhibitor combinations may be unreliable for the treatment of organisms producing extended-spectrum beta-lactamases.

In-vitro potencies of histamine H2-receptor antagonists on tetraethylammonium uptake in rat renal brush-border membrane vesicles

The histamine H2 antagonists cimetidine, ranitidine and famotidine are organic bases that are cleared from the body by active renal tubular secretion involving the organic cation transporter in the proximal tubule. To determine the potential for competition for the transporter between these drugs and other drugs, their inhibitory potencies were assessed in-vitro, using rat renal brush-border membrane vesicles and tetraethylammonium as the substrate. The concentration-dependent effect of cimetidine, ranitidine and famotidine on the 15-s proton-stimulated uptake of tetraethylammonium into the membrane vesicles was studied using five different rat kidneys. The order of inhibition potencies was: cimetidine (mean IC50 = 1.07 microM) > famotidine (2.43 microM) < ranitidine (55.4 microM). The results indicate the potential for drug interactions in the kidney, especially for cimetidine and famotidine.

Treatment of cerebral vasospasm with intra-arterial papaverine

Cerebral vasospasm continues to be the leading treatable cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage. In this preliminary anecdotal series of 12 patients who were candidates for balloon angioplasty, vasospasm was treated instead with intra-arterial papaverine. Eight patients had marked angiographic reversal of the arterial narrowing following papaverine infusion, four of whom showed dramatic reversal of profound neurological deficits. Two patients deteriorated clinically 5 days after the initially successful papaverine infusions. In both, repeat angiography demonstrated severe recurrent vasospasm, which was partially reversed with a second intra-arterial papaverine treatment. Two patients developed focal neurological deficits during papaverine infusion, which resolved spontaneously over several hours after cessation of the intra-arterial infusion. Arterial narrowing in the posterior circulation and middle cerebral artery distribution appeared to be more responsive to papaverine infusion than was spasm in the anterior cerebral arteries. The infusion of 300 mg of papaverine over 1 hour seemed to be an adequate and safe dose to effect these angiographic and clinical improvements.

Development of D1 and D2 dopamine receptors and associated second messenger systems in fetal striatal transplants

Stereotactic implantation of fetal brain regional anlage into adult host brain ("brain transplantation") appears to be an increasingly viable strategy for therapy of neurodegenerative diseases. We have studied implantation of fetal striatum into adult striatum, previously lesioned by neurotoxic amino acid injection, as a model for transplantation therapy of Huntington's disease. The beginning of behavioral recovery to apomorphine is not apparent until 6.5 months after implantation. By 4 months after implantation cerebral blood flow through the implants appears equal to that in the intact contralateral striatum. At this time, cerebral glucose utilization is reduced in the implants but increases following apomorphine treatment. The development of D1 and D2 dopamine (DA) receptors is markedly deficient in the striatal grafts at both 4 and 6.5 months after implantation. Very little D2 radioligand binding was observed in the grafts at either time point; D1 receptors appeared in a patchy fashion by 6.5 months at densities approaching normal striatum. In situ hybridization of D2 dopamine receptor mRNA demonstrated robust hybridization signal in normal striatum and accumbens but no signal in 6.5-month-old striatal grafts. Adenylate cyclase (AC) activity, examined with high-affinity [3H]forskolin binding, also appeared in patches similar to D1 receptors at 6.5 months. In contrast, protein kinase C activity, labeled with [3H]phorbol ester, was very apparent in the grafts at both time points. Higher and generally homogenous densities of muscarinic cholinergic receptors, assessed with [3H]QNB binding, develop in the grafts, but there appear to be few functioning cholinergic terminals, as measured by [3H]hemicholinium binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective study of clinical, laboratory, and ancillary staff with accidental exposures to blood or body fluids from patients infected with HIV

In a prospective study of 150 health care workers in the United Kingdom who had been accidentally exposed to the human immunodeficiency virus no evidence of transmission was found. Larger studies in the United States and anecdotal accounts in publications from other countries confirm that the risk of occupational infection is very low. Health care workers must adopt safe procedures at all times, however, to avoid exposure to infection.

Atraumatic removal of a well-fixed porous ingrowth hip prosthesis

The authors describe their experience in the removal of a firmly fixed porous coated femoral component of a bipolar hip prosthesis in a 36-year-old man on a methadone maintenance program. The uncemented prosthesis had been implanted for 15 months when the patient complained of hip pain. A methicillin-resistant Staphylococcus aureus infection was found in the hip joint. It was decided to remove the femoral component when the infection failed to respond to irrigation, debridement, and several weeks of intravenous antibiotic therapy and because the patient developed early signs of impending renal compromise and a deterioration of his general nutritional status. The technique for separating and removing the well-fixed porous ingrowth component from its intramedullary environment without damaging the cortical tube of the proximal femur is described.

Speech and voice parameters of depression: a pilot study

This pilot study tests one model for interdisciplinary research between speech science and psychiatry. Strengths and weaknesses of the model are noted. Thirteen depressed subjects were evaluated before and after treatment with antidepressant medication. Subjects were rated on scales for severity of depression and speech deviations. Scores on a depressed voice scale, comprising seven of the speech dimensions found to be most consistently altered in depression, showed significant improvement after treatment for depression. The constellation of speech signs found in depression suggested a hypokinetic disturbance of the extrapyramidal system. Several directions for further inquiry into this potential relationship are suggested.

Chronic arthritis associated with the presence of intrasynovial rubella virus

In this report we present 21 instances in which live rubella virus was isolated from synovial fluid obtained from 6 cases of inflammatory oligoarthritis or polyarthritis over a period of 2 years in the absence of firm clinical evidence of rubella. In 3 cases (cases 1, 2, 6,) a persistent oligoarthritis predominantly affecting the knee joints occurred in 2 adult women and one man, lasting to date 27, 29, and 18 months respectively, and in one of these cases virions were found in cells of the synovial membrane. In case 3 a boy of 9 presented with an illness indistinguishable from the systemic variety of juvenile chronic arthritis (Still's disease). In case 4 a young man with persistent monoarthritis was found to have ankylosing spondylitis, and in case 5 a progressive erosive polyarthritis developed 5 years after an attack of rubella complicated by rubella arthritis. The virus was identified by a variety of virological techniques and infection confirmed by immunofluorescence and (in one case) electron microscopy.