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The L1 cell adhesion molecule NrCAM (Neuron-glia related cell adhesion molecule) functions as a co-receptor for secreted class 3 Semaphorins to prune subpopulations of dendritic spines on apical dendrites of pyramidal neurons in the developing mouse neocortex. The developing spine cytoskeleton is enriched in actin filaments, but a small number of microtubules have been shown to enter the spine apparently trafficking vesicles to the membrane. Doublecortin-like kinase 1 (DCLK1) is a member of the Doublecortin (DCX) family of microtubule-binding proteins with serine/threonine kinase activity. To determine if DCLK1 plays a role in spine remodeling, we generated a tamoxifen-inducible mouse line (Nex1Cre-ERT2: DCLK1

The L1 cell adhesion molecule NrCAM (Neuron-glia related cell adhesion molecule) functions as a co-receptor for secreted class 3 Semaphorins to prune subpopulations of dendritic spines on apical dendrites of pyramidal neurons in the developing mouse neocortex. The developing spine cytoskeleton is enriched in actin filaments but a small number of microtubules have been shown to enter the spine apparently trafficking vesicles to the membrane. Doublecortin-like kinase 1 (DCLK1) is a member of the Doublecortin (DCX) family of microtubule-binding proteins with serine/threonine kinase activity. To determine if DCLK1 plays a role in spine remodeling, we generated a tamoxifen-inducible mouse line (Nex1Cre-ERT2: DCLK1flox/flox : RCE) to delete microtubule binding isoforms of DCLK1 from pyramidal neurons during postnatal stages of spine development. Homozygous DCLK1 conditional mutant mice exhibited decreased spine density on apical dendrites of pyramidal neurons in the prefrontal cortex (layer 2/3). Mature mushroom spines were selectively decreased upon DCLK1 deletion but dendritic arborization was unaltered. Mutagenesis and binding studies revealed that DCLK1 bound NrCAM at the conserved FIGQY1231 motif in the NrCAM cytoplasmic domain, a known interaction site for the actin-spectrin adaptor Ankyrin. These findings demonstrate that DCLK1 facilitates spine growth and maturation on cortical pyramidal neurons in the mouse prefrontal cortex potentially through microtubule and NrCAM interactions.

A shift in macrophage metabolism from oxidative phosphorylation to aerobic glycolysis is a requirement for activation to effectively combat invading pathogens. Francisella tularensis is a facultative intracellular bacterium that causes an acute, fatal disease called tularemia. Its primary mechanism of virulence is its ability to evade and suppress inflammatory responses while replicating in the cytosol of macrophages. The means by which F. tularensis modulates macrophage activation are not fully elucidated. In this study, we demonstrate that virulent F. tularensis impairs production of inflammatory cytokines in primary macrophages by preventing their shift to aerobic glycolysis, as evidenced by the downregulation of hypoxia inducible factor 1α and failure to upregulate pfkfb3. We also show that Francisella capsule is required for this process. In addition to modulating inflammatory responses, inhibition of glycolysis in host cells is also required for early replication of virulent Francisella. Taken together, our data demonstrate that metabolic reprogramming of host cells by F. tularensis is a key component of both inhibition of host defense mechanisms and replication of the bacterium.

Neurocan is a chondroitin sulfate proteoglycan present in perineuronal nets, which are associated with closure of the critical period of synaptic plasticity. During postnatal development of the neocortex dendritic spines on pyramidal neurons are initially overproduced; later they are pruned to achieve an appropriate balance of excitatory to inhibitory synapses. Little is understood about how spine pruning is terminated upon maturation. NrCAM (Neuron-glial related cell adhesion molecule) was found to mediate spine pruning as a subunit of the receptor complex for the repellent ligand Semaphorin 3F (Sema3F). As shown here in the postnatal mouse frontal and visual neocortex, Neurocan was localized at both light and electron microscopic level to the cell surface of cortical pyramidal neurons and was adjacent to neuronal processes and dendritic spines. Sema3F-induced spine elimination was inhibited by Neurocan in cortical neuron cultures. Neurocan also blocked Sema3F-induced morphological retraction in COS-7 cells, which was mediated through NrCAM and other subunits of the Sema3F holoreceptor, Neuropilin-2, and PlexinA3. Cell binding and ELISA assays demonstrated an association of Neurocan with NrCAM. Glycosaminoglycan chain interactions of Neurocan were required for inhibition of Sema3F-induced spine elimination, but the C-terminal sushi domain was dispensable. These results describe a novel mechanism wherein Neurocan inhibits NrCAM/Sema3F-induced spine elimination.

Perineuronal nets (PNNs) are implicated in closure of critical periods of synaptic plasticity in the brain, but the molecular mechanisms by which PNNs regulate synapse development are obscure. A receptor complex of NCAM and EphA3 mediates postnatal remodeling of inhibitory perisomatic synapses of GABAergic interneurons onto pyramidal cells in the mouse frontal cortex necessary for excitatory/inhibitory balance. Here it is shown that enzymatic removal of PNN glycosaminoglycan chains decreased the density of GABAergic perisomatic synapses in mouse organotypic cortical slice cultures. Neurocan, a key component of PNNs, was expressed in postnatal frontal cortex in apposition to perisomatic synapses of parvalbumin-positive interneurons. Polysialylated NCAM (PSA-NCAM), which is required for ephrin-dependent synapse remodeling, bound less efficiently to neurocan than mature, non-PSA-NCAM. Neurocan bound the non-polysialylated form of NCAM at the EphA3 binding site within the immunoglobulin-2 domain. Neurocan inhibited NCAM/EphA3 association, membrane clustering of NCAM/EphA3 in cortical interneuron axons, EphA3 kinase activation, and ephrin-A5-induced growth cone collapse. These studies delineate a novel mechanism wherein neurocan inhibits NCAM/EphA3 signaling and axonal repulsion, which may terminate postnatal remodeling of interneuron axons to stabilize perisomatic synapses in vivo.

One hundred years ago on 14 June 1905, Themistocles Zammit, a Maltese doctor, found that five out of six goats reacted to the blood test for brucellosis, then known as Mediterranean or Malta Fever. Zammit not only made the initial discovery of naturally infected goats but also consistently pursued the subject of brucellosis by experiment, by epidemiology and by devising tests which were used by others—e.g. Zammit’s test. He discovered that the milk of an inoculated goat contained the bacteria., peer-reviewed

Analysis of brucellosis epidemics in ships of the Mediterranean fleet in the nineteenth century are most easily explained by aerosol transmission in grossly overcrowded, hot and humid confined spaces.

Several theories of a possible origin of AIDS from poliovaccines contaminated with simian immunodeficiency viruses have been suggested for use in class discussions Contamination of cultures or cells used for research, therapy or vaccines is always possible. Poliovaccines were contaminated with a simian virus which had the potential to produce cancers, and several people have suggested that contaminated polioviruses were responsible for the AIDS epidemic. If such episodes and theories are to be discussed by students, discussion should be based on all the evidence available, not just on newspaper or popular articles. The contamination of poliovaccines is also discussed. When such contamination is found, what can or should be done to discover if vaccines will suffer harm is a difficult question. Theories of the origin of AIDS are not scientific as they cannot be disproved. Nevertheless, it is important that students examine all the evidence to see if the theories are likely or far-fetched. If the public desp...

The disease we now know as brucellosis was first discovered in the 1850s in Malta. It came to the attention of British medical officers serving on the island after the Crimean War. It was easy to eliminate the disease in British servicemen, but very difficult to reach Maltese citizens. Over the decades, more and more Maltese were infected asthe control measures introduced were half-hearted and were often not even enforced. The work of Dr Themistocles Zammit showed that infected goats transmitted brucellosis and that banning use of their milk would be effective. Pasteurisation was not introduced onto the island until the 1930s, when the production of cheap, small sterile containers became possible. Transmission was also possible through sexual contact and by inhalation when people were crowded in hot airless conditions. Success in controlling the disease requires sensible, strict control of animals and the elimination of infected ones, but will fail without an educated public willing to help. In Malta, failure to control rogue flocks and small flocks kept for family use led to an epidemic caused by the sale of cheeselets (small cheeses). In 2005, nearly a century after Zammit's discovery, Malta was finally free of brucellosis.

Francisella tularensis (Ft) is a gram negative, facultative intracellular bacterium that is the causative agent of pneumonic tularemia. Inhalation of as a few as 15 organisms can result in lethal infection. The virulence of Ft is attributed to the bacterium’s ability to both evade and suppress the activation of macrophages. However, the mechanisms and bacterial components required for evasion and suppression by Ft are unclear. Activation of macrophages and induction of antimicrobial responses requires a metabolic shift from oxidative phosphorylation to aerobic glycolysis. Thus, we postulated that Ft manipulates host metabolism as a mechanism of virulence. We established that virulent Ft suppresses induction of aerobic glycolysis among infected macrophages. Moreover, utilizing purified capsule and defined capsule mutants, we elucidated a novel role for Ft capsule as a component contributing to this suppression. The requirement for inhibition of host cell glycolysis in Ft pathogenesis was confirmed via direct inhibition of glycolysis using 2-deoxyglucose. Addition of 2-DG to macrophages infected with capsule mutants partially restored the early intracellular survival and replication of these bacteria, and impaired the secretion of pro-inflammatory cytokines that is typical of infection with these mutants. Together, our data demonstrate that manipulation of host metabolism is an important component of Ft pathogenesis and uncovers a previously unappreciated function of bacterial capsule in the virulence of Ft.

Dr Zammit's experiments showed that brucellosis was transmitted by the milk of goats that did not show signs of infection or ill health. The British forces in Malta banned the use of goats' milk and brucellosis was eliminated in those forces. This research was published in the Proceedings of the Royal Society and earned him an Honorary DLitt from Oxford University and the Kingsley Medal of the Liverpool School of Tropical Medicine. The King knighted him. He was the great Maltese polymath but there is a mystery concerning his name.

Adults accompanying 64 children attending a hospital out-patient clinic were questioned about treatment and injections given for illnesses in the previous month. Half the children had received injections, almost all given by private doctors: we consider most of these injections to have been unnecessary. Three girls were paralysed by aggravation poliomyelitis after unnecessary injections. Adults approved of injections although they did not know what was injected.

By the early 1950s, the syringe and needle had become immensely popular across the whole of the tropics and subtropics. Patients wanted injections, doctors wanted to give injections, traditional healers had incorporated injections into their practices and all kinds of paramedical workers and others were prepared to give injections. Visitors to Europe and North America returned with syringes and needles for use with their families. All medical interventions have some risk: some medical interventions have very high risks if they are misused. The risk from an injection is small if the syringe and needle and what is injected are sterile: if the substance injected is therapeutically necessary, the risk is justifiable. However, injections were enthusiastically adopted in communities with no knowledge of sterility, no comprehension of infectious diseases and no money or equipment to ensure sterility. Although everyone has been aware of the prevalence of unsterile injections in developing countries, there has been little in the medical literature except that written by medical anthropologists. The epidemic of human immuno­ deficiency virus (HIV) has alerted the World Health Organization to the possible dangers unless all immunizing injections are sterile, but the risks to children from injections given for fever, upper respiratory infections, diarrhoea, and every other

Immunology is not an easy subject—it is complicated, and students soon lose interest. Lecturers can see the enthusiasm fading away and seek to enliven their lectures. I was intrigued by a well known US bacteriologist of the 1930s who had apparently solved the difficulty of keeping his students' attention when talking about complement—a complicated topic of little interest to them. He would enter …

Diseases may be known by the localities where they were first described or were common. Thus undulant fever, a particularly debilitating illness that often led to rheumatism, became known as Malta fever—to which many Maltese objected. There were many other names for it: Rock or Gibraltar fever, as well as Cyprus, Neapolitan, Italian, and Crimean fever. But Malta fever was the favoured name. Mediterranean fever was recommended by an international congress but was really unsuitable as the fever was found in many other localities. Sir David Bruce discovered the causative organism in the spleen of a soldier who had died in Malta …

The NASA Independent Verification & Validation (IV&V) Facility's metrics data program (MDP) has been tasked with collecting data in the form of metrics on software products from various NASA Projects. The goals of the program include: improve the effectiveness of software assurance, evaluate the effectiveness of current metrics, identify and include new metrics, improve the effectiveness of software research, and improve the ability of projects to predict software errors early in the lifecycle. This article presents a model for accomplishing these goals from a requirements position. Identification of metrics from a requirements perspective approach presents a particularly difficult challenge. First, there are few automated tools to assist in collection of requirement based metrics. Secondly, few metrics have been identified for requirements. In this article, an approach is presented for capturing requirements measurements generated utilizing Goddard Space Flight Center (GSFC) Software Assurance Technology Center's (SATC) automated requirements measurement (ARM) tool. These measurements are used in combination with newly identified measurements to identify and assign a risk level metric to each requirement. The assigned requirement risk level represents an indicator for early lifecycle analysis for use in prediction of problem requirements and areas within the software that could be more prone to errors. The early identification of high risk areas allows for risk mitigation and application during planning of future development, test, and maintenance activities.

In many countries, the treatment of choice for all fevers is one or more injections. These injections are associated with a risk of nerve damage. If cases of poliomyelitis are not to be missed, the diagnosis of injection trauma or traumatic neuritis (TN) must be exact. The guides for distinguishing between TN and polio are not clear. It is probable that some cases of polio are misdiagnosed as TN. As three-quarters of children with paralytic polio receive injections just before the onset of paralysis, their paralysis may be mistaken for TN. Clearer guidelines are proposed, together with suggestions for better documentation of muscles injected and paralysed. All cases of reported TN should be monitored and new diagnostic guidelines published. To protect their children, mothers must be educated to understand that injections for fever can cause harm. This must be an important part of the eradication programme for poliomyelitis.

In that they were made in temperate countries, most of the studies on poliomyelitis may not apply in sub-continent of endemic infantile paralysis. This review brings together data on polio in India, to present any changes which may have occurred since 1940. Only about 2% of children with polio die in the acute illness; about 95% of all cases have paralysis of one or both legs. In lameness surveys the adjustments for deaths and for arm paralysis are unnecessary and inflate the prevalence. Surveys suggest that prevalence has risen, but there may be other explanations for the figures. Around sentinel centres with effective cold chains, prevalence has decreased rapidly. The figures of the National Baseline Prevalence survey are examined. There are few cases of provocation, but a new phenomenon of aggravation by unnecessary intramuscular injections given to children with fever has been described. Such unnecessary injections are thought to be the cause of more severe paralysis in about 45% of cases and of converting a non-paralytic attack into paralysis in another 30% of the perhaps 200,000 cases in India each year. Aggravation is thought to be caused by a mechanism similar to the effects of physical activity. It is possible that massage might have a similar effect. Abscesses or their treatment may precipitate paralysis. The median age of paralysis fell by almost a half from about 2 yr to 1 yr, but may now have risen as many younger children receive vaccine. Rehabilitation has been neglected, with long lasting consequences. Assessment of disability should be based on need and not on current ability. Ethically, prevalence surveys should offer opportunity for immunization and rehabilitation. Prevalence of paralysis, numbers attending for rehabilitation and immunization have been analysed by gender and differences examined. The gender-gap widens with age after paralysis: there may be a high mortality among girls with paralysis. Past prevalence calculated from surveys might be seriously underestimated if many girls have died. The monthly pattern of polio was no different in epidemic years. Pulse immunization could be tried just before the seasonal rise each year. Difficulties of comparing vaccination schedules and the criteria for assessing the potency of vaccine are analysed. Paralysis among Indian soldiers in World War II suggests that adult cases may occur, but are not reported. Present investigations should concentrate on babies and adult cases. Research using virulent strains should be prohibited. The very low case-fatality rate suggests that many of the circulating viruses are of low virulence. The increasing proportion of cases with unnecessary injections just prior to paralysis might have caused the lower median age of paralysis, the severity of paralysis and at least part of the increasing prevalence of polio. The seasonal increases of polio might, in part, be a reflection of the injections given for fever caused by other infections. A national campaign against unnecessary injections for young children is urgently required. For children with fever, there is a strong case for postponing even DPT injections.

Between 1990 and 1994 in Africa, the percentage of children administered 3 doses of oral polio vaccine by 12 months old has fallen to about 80%. Any polio eradication program is successful when circulating oral polio vaccine (OPV) supplants wild polio viruses. Thus, any unimmunized children will grow up without encountering any wild virus. As the pool of unimmunized children grows, the chance of an imported wild virus circulating and causing an epidemic increases, as occurred in the recent epidemics in Holland and Oman. The wild virus is still circulating in Africa (e.g., Namibia in 1993, 53 paralyzed children). Immunization of all children and the reporting of every polio case are needed to achieve polio eradication. Even though 98% of children were immunized with 3 doses of OPV in a town in India, several children still became infected with the polio virus. When 5 doses of OPV were administered, no more cases of polio emerged in the town. In the environs of the town, the intensive polio control program reduced the number of cases from more than 1000 to 36 between 1987 and 1994. The program consists of a network of more than 450 reporting agents based in primary health care centers, hospitals, and clinics (public and private sectors). Despite program staff's hard work, several surveys did not find all reported cases and found several unreported cases, indicating the difficulties encountered by a polio control program. Few studies of polio in Africa are published, yet thousands of polio cases occur annually in Africa. Civil war, famine, and many refugees make it more difficult to control polio in Africa. These situations facilitate the spread of diarrheal diseases. Political commitment, ability, and funds are needed to vaccinate all children and maintain surveillance for at least 10 years in order to eradicate polio. Days of tranquility are needed in conflict zones in Africa to allow workers to distribute OPV.

At the beginning of the twentieth century, poliomyelitis presented a scientific and medical challenge of a complexity similar to that of AIDS now. Research on polio, mainly in the US, gradually became focussed to solving basic questions, but was held up by the lack of suitable laboratory techniques. The financing of the research and the wide range of basic topics funded were the model for later medical science. The problem of polio, at least in the wealthier temperate countries, has been solved by the use of vaccines. Many fundamental questions about the mechanism of the disease remained unsolved and this lack of knowledge has contributed to many unfortunate accidents. The history of polio has many lessons for AIDS researchers.

Paralytic poliomyelitis attacks 1-10/1000 young children (median age 12 months) in Africa despite the fact that the disease is preventable by immunization. Oral poliovaccine is cheap, safe, and effective, but it depends on a cold chain for storage. The new vaccination schedule calls for a dose at birth and at 3, 4, and 5 months of age. This is difficult to manage, and most immunization programs key success to full immunization by 12 months, which is too late for polio. Past efforts have centered on immunizing an increasing proportion of children in an area, but it might be better to try to cover all the children in a specific region. Despite immunization, a few children may contract the disease through circulation of wild viruses which can only be banned by large-scale immunization programs. Wild poliovirus may travel unnoticed through immune populations, placing nonimmunes at risk. In the presence of natural or manmade disasters, the cold chain and immunization against polio will be one of the first health casualties. Poliovirus will persist in reservoirs of the African population until conditions improve. The vaccine should be administered to HIV-positive children. One practice which can lead to paralysis is the administration of injections to babies with a fever. An injection under these circumstances, especially if the needle and syringe are not sterile, causes an inflammatory response. If the cause of the fever is a poliovirus infection which has reached the spinal cord, the resulting paralysis is more severe after an injection. In children who are incubating nonparalytic polio, the injected limb(s) will become paralyzed. Intramuscular injections, exercise, and lumbar puncture should, therefore, be avoided during fever. After paralysis, regular physiotherapy should result in some improvement, but injected limbs are less likely to recover function. The only injections given to babies and young children in community health centers should be immunizations. A great deal of work is necessary to change the attitudes of parents and health workers, but the evils of unnecessary injections must no longer be ignored.

Death of motor neurones following invasion of the central nervous system by poliovirus may result in paralysis of specific muscles. Virulence may be tested by injection into monkeys by routes which bypass natural infection. Transmissibility is also very important, but cannot be measured, only inferred. An infection may lead to immunity or paralysis. In epidemics, the highest incidence among children 0-2 years was 2% and among those over 10 years was 25%: these figures fit a model of genetic susceptibility of homozygotes and heterozygotes with phenotypic susceptibility increasing with age. Hypogamma-globulinemics, some neonates and pregnant women are more susceptible than others. Intra-muscular injections may increase the risk of paralysis. Strenuous exercise and IM injections given when poliovirus has already reached the spinal cord can increase the severity of paralysis or convert a non-paralytic attack to paralysis. Although vaccines reduced polio in temperate countries, polio was thought to be no problem in the tropics. Since 1977 polio has been recognised as a massive problem in the third world: because it affects babies and very young children, it is properly infantile paralysis.

A new theory of how poliovirus reaches the central nervous system (CNS)--that it enters at many peripheral nerve endings with passage along nerve pathways to the CNS, with limited dispersal in the CNS--is used in making predictions of incubation periods, and these are compared with data from the literature and with predictions from other theories. The virus transit speed along the nerve of 2.4 mm/h has been used in calculating the incubation time. The calculated incubation time for Cutter vaccinees is similar to the actual times reported, and the calculated minimal and maximal incubation times in humans are similar to the published ranges. Incubation times in different animals and for different paralyses are explained. The pathology of lesions in humans and the consequent paralyses are compatible with the model. Tonsillectomy-associated poliomyelitis is reviewed and discussed in relation to possible entry of virus from peripheral nerve endings in muscle. Increased lymphocyte concentrations in the muscle may account for continuing susceptibility after tonsillectomy. Severe paralysis following exercise is explained as an effect of increased blood supply to nerves in the CNS that has already been invaded by virus. In developing countries, the phenomenon of paralysis in the injected muscle a few hours after injection in febrile children may occur in a similar fashion. The entry of poliovirus from many sites at nerve endings in muscles is consistent with clinical, experimental, and pathologic data and provides an explanation of the incubation times and related phenomena of poliomyelitis.

Pakistan reported 1046 cases of paralytic poliomyelitis in 1992. In 1993, 78% of all children received three doses of Oral poliovaccine (OPV), but there were 1115 cases to the end of September. As it is not feasible to make house to house surveys to check, we do not know how many children with polio fall outside the reports from surveillance centers which are mainly large hospitals. Hospitals have a few records and staff do no ask questions about injections give prior to paralysis. In December 1993, I examined 29 children with polio at a camp in a small town in North West Frontier Province and inspected records of 226 polio children at two clinics in Peshawer, Pakistan. Children without injections during the prodromal period had an equal chance of paralysis in their left and right legs (Table 1), as reported previously in India. However, of the 152 children with suitable records, 136 (89%) had received an unnecessary injection 48 h or less before paralysis and there was almost complete correlation of paralysisand the site of injection. Children who had received an injection developed in 97% of the injected legs compared with only 7% of the legs which were not injected (Table 2). Injections are rarely given in the arm: 2% of the children had arm paralysis only and another 3% had paralysis involving arms and legs. In areas where wild poliovirus circulates, some children are taken to a doctor or other health worker or healer, with a fever caused by the poliovirus infection which has already reached the spinal cord. In these children, unsterile, unnecessary injection of antibiotics, etc., given for fever can cause aggravation polio within 48 h of the injection, changing non-paralytic attacks to frank paralysis which, typically, occurs only in the injected limb. If the injection is given in a limb which is already programmed for paralysis, then that paralysis is made more severe and the limb is less likely to recover than one without injections. The injections must cause inflammation in the muscle which causes changes in the corresponding sections of the spinal cord. In Peshawer, as only 7% of uninjected legs were paralysed, most residual paralysis probably results from infections with polioviruses of low virulence: and unnecessary injections change what would be non-paralytic attacks into paralysis. In some of the Pakistan children, legs without injections may have recovered from initial paralysis or have so slight a paralysis that the children were not brought to rehabilitation clinics. Of 190 children attending a Rehabilitation Center in Peshawer, 86% had received an injection prior to paralysis. The correlation of injection and paralysis was very similar to that reported in this paper. Muscle strengths of injected limbs were much weaker than those of uninjected limbs were much weaker t.hn those of uninjected limbs, as found in Indian children. In Pakistan Greetham also found that 60% of 1279 Afghan refugee children with residual paralysis caused by polio had received intramuscular injections just prior to paralysis.

(1993). Lind and scurvy: insight and hindsight. Journal of Biological Education: Vol. 27, No. 1, pp. 5-6.

After speaking at the medical school in Mangalore, India, in 1992 I stopped at the mission hospital in Miraj to visit a former student and was introduced to the Bishop of Nagpur. We talked of the work done for children paralysed by poliomyelitis at facilities that had formerly been used for patients with advanced leprosy. I talked of the problems of unnecessary injections and their effect of increasing the incidence of paralysis. He …

I have often wondered if the Knights of Malta had a better recovery rate from operations than others, “The Sacred lnfirmary, overlooking Fort Saint Elmo, at the tip of Valletta, Malta GC, was the most celebrated institution …