[Toward a better understanding of fatigue in schizophrenia]

Despite being one of the most common complaints of people with schizophrenia, fatigue remains largely unexplored in this population. The lack of knowledge regarding this complex symptom makes it often underdiagnosed and undertreated in schizophrenia. The aim of this brief perspective review is to outline the potential origins (distinguishing primary and secondary fatigue) and consequences of fatigue and to explore some potential treatments in this population. The current literature in schizophrenia has mainly investigated fatigue as a trait, using a self-administered questionnaire. Beyond this observational approach, which does not allow to capture the symptom in real life situations where high levels of fatigue can emerge rapidly, we propose to consider the state level of fatigue, for instance occurring after a prolonged period of cognitive activity (i.e. mental fatigue). We elaborate on the potential relationships between mental fatigue and negative symptoms of schizophrenia and propose some research avenues to test the effects of acute fatigue on effort intentions and behaviours. The consideration of the multidimensional aspects of fatigue will allow to move beyond the sole pharmacological approach to treat fatigue in schizophrenia. Targeting the cognitive as well as the performance components of fatigue through interventions such as concomitant aerobic exercise - mental training offers attractive prospects to reduce fatigue in this population and minimize its functional negative impact.

Faecal metabolite deficit, gut inflammation and diet in Parkinson's disease: Integrative analysis indicates inflammatory response syndrome

BACKGROUND

Gut-brain axis is widely implicated in the pathophysiology of Parkinson's disease (PD). We take an integrated approach to considering the gut as a target for disease-modifying intervention, using continuous measurements of disease facets irrespective of diagnostic divide.

METHODS

We characterised 77 participants with diagnosed-PD, 113 without, by dietary/exogenous substance intake, faecal metabolome, intestinal inflammation, serum cytokines/chemokines, clinical phenotype including colonic transit time. Complete-linkage hierarchical cluster analysis of metabolites discriminant for PD-status was performed.

RESULTS

Longer colonic transit was linked to deficits in faecal short-chain-fatty acids outside PD, to a 'tryptophan-containing metabolite cluster' overall. Phenotypic cluster analysis aggregated colonic transit with brady/hypokinesia, tremor, sleep disorder and dysosmia, each individually associated with tryptophan-cluster deficit. Overall, a faster pulse was associated with deficits in a metabolite cluster including benzoic acid and an imidazole-ring compound (anti-fungals) and vitamin B3 (anti-inflammatory) and with higher serum CCL20 (chemotactic for lymphocytes/dendritic cells towards mucosal epithelium). The faster pulse in PD was irrespective of postural hypotension. The benzoic acid-cluster deficit was linked to (well-recognised) lower caffeine and alcohol intakes, tryptophan-cluster deficit to higher maltose intake. Free-sugar intake was increased in PD, maltose intake being 63% higher (p = .001). Faecal calprotectin was 44% (95% CI 5%, 98%) greater in PD [p = .001, adjusted for proton-pump inhibitors (p = .001)], with 16% of PD-probands exceeding a cut-point for clinically significant inflammation compatible with inflammatory bowel disease. Higher maltose intake was associated with exceeding this calprotectin cut-point.

CONCLUSIONS

Emerging picture is of (i) clinical phenotype being described by deficits in microbial metabolites essential to gut health; (ii) intestinal inflammation; (iii) a systemic inflammatory response syndrome.

455 A Case of An Unusual Penetrating Brain Injury

Introduction

Penetrating brain injuries (PBI) are less common than closed head traumas. Interest in frontal lobe injuries dates back to 1848’s famous Phineas Gage incident. Here, we report a case of a construction worker, who showed a remarkable neuropsychiatric outcome following a workplace accident.

Case Presentation

45year old gentleman came with complaint of a foreign body accidentally lodged in his forehead. He had no neurological deficits or CSF leak. X-ray revealed that a 5.5cm metallic screw was penetrating his skull, headfirst; CT revealed that approximately 3cm of the screw was in the frontal sinus. He was given antiepileptics and antibiotics prophylactically. Surgically the screw was removed by raising a bone flap and mobilizing the screw carefully by cutting the dura and adequate irrigation, causing minimal damage to the brain parenchyma. The dural deficits were repaired and the frontal sinus was canalized, then a drain was placed, and the patient was shifted to ICU for postoperative monitoring.

Discussion

It is important to prognosticate PBI as they can have neurological deficits that may be lifelong. Understanding the mechanism of injury, aggressive medical management and immediate surgical intervention may lead to improved outcomes. A foreign object of the size of 5.5cm, completely penetrating the skull would have otherwise resulted in extensive parenchymal damage. Literature suggests that no two people have an identical frontal sinus. In our patient the size the frontal sinus has served the purpose of protection against PBI and has resulted in minimal parenchymal injury (of only about 1cm).

Glypican-2 levels in cerebrospinal fluid predict the status of adult hippocampal neurogenesis

Adult hippocampal neurogenesis is a remarkable form of brain plasticity through which new neurons are generated throughout life. Despite its important roles in cognition and emotion and its modulation in various preclinical disease models, the functional importance of adult hippocampal neurogenesis in human health has not been revealed because of a lack of tools for monitoring adult neurogenesis in vivo. Therefore, we performed an unbiased proteomics screen to identify novel proteins expressed during neuronal differentiation using a human neural stem cell model, and we identified the proteoglycan Glypican-2 (Gpc2) as a putative secreted marker of immature neurons. Exogenous Gpc2 binds to FGF2 and inhibits FGF2-induced neural progenitor cell proliferation. Gpc2 is enriched in neurogenic regions of the adult brain. Its expression is increased by physiological stimuli that increase hippocampal neurogenesis and decreased in transgenic models in which neurogenesis is selectively ablated. Changes in neurogenesis also result in changes in Gpc2 protein level in cerebrospinal fluid (CSF). Gpc2 is detectable in adult human CSF, and first pilot experiments with a longitudinal cohort indicate a decrease over time. Thus, Gpc2 may serve as a potential marker to monitor adult neurogenesis in both animal and human physiology and disease, warranting future studies.

Nonspecific positivity on the Luminex crossmatch assay for anti-human leukocyte antigen antibodies due to antibodies directed against the antibody coated beads

Two cases are described of previously unreported false positivity on the Luminex crossmatch assay due to non HLA specific antibodies directed against the beads. In both cases the Luminex crossmatch indicated the presence of donor specific antibodies to class II HLA antigens, which was not substantiated by the clinical scenario or other assays. We could demonstrate the non specificity of these antibodies through using the same assay in a modified form where beads were unexposed to cell lysate and therefore did not carry HLA antigens at all. These cases further serve to emphasize the absolute necessity of correlating positive results with the priming history, and confirming their relevance using other platforms.

Peripheral aetiopathogenic drivers and mediators of Parkinson's disease and co-morbidities: role of gastrointestinal microbiota

We seek an aetiopathogenic model for the spectrum of Parkinson's disease (PD), functional bowel disease, depression and cognitive impairment. The adopted concept is that systemic immuno-inflammatory processes mediate neuro-inflammation. The model would be based on phenotype, exposome (including gastrointestinal microbiome), milieu (immuno-inflammatory and metabolome), human genetics and their interactions. It would enable a patient's position, to be understood in terms of drivers, perpetuators and mediators, and a future position, with and without intervention, predicted. Even the cardinal facets of PD may have different drivers: halting one may allow escape down subordinate pathways. Peptic ulceration is prodromal to PD. In our randomised placebo-controlled trial, hypokinesia improved over the year following biopsy-proven Helicobacter pylori eradication and rigidity worsened. This was independent of any (stable, long t½) antiparkinsonian medication. There are pointers to an autoimmune process: for example, surveillance-confirmed hypokinesia effect was indication specific. During surveillance, successive antimicrobial courses, other than for Helicobacter, were associated with cumulative increase in rigidity. Exhibiting laxatives appeared to stem the overall temporal increase, despite antiparkinsonian medication, in rigidity. Thus, intestinal dysbiosis may be a major source of bystander neuronal damage. There are biological gradients of objective measures of PD facets on circulating inflammatory markers and leucocyte subset counts. Moreover, lactulose hydrogen breath test positivity for small-intestinal bacterial overgrowth (present in two thirds of PD patients) is associated with the same subsets: higher natural killer and total CD4+ counts and lower neutrophils. With greater aetiopathogenic understanding, relatively low cost and on-the-shelf medication could have a major impact. A new generation of animal models, based on the gut microbiome, is envisaged.

[Seronegative antiphospholipid syndrome, catastrophic syndrome, new anticoagulants: learning from a difficult case report]

INTRODUCTION

The diagnosis of the antiphospholipid syndrome (APS) is based on clinical and biological criteria including the persistent presence of antiphospholipid antibodies and thrombotic events or pregnancy morbidity. Heparins relayed by vitamin K antagonists (VKA) are the gold standard treatment for thrombosis.

CASE REPORT

We report a 17-year-old man who presented with an initially seronegative antiphospholipid syndrome, in whom the diagnosis was late, only obtained after anticoagulation withdrawing, when a catastrophic antiphospholipid syndrome (CAPS) with cutaneous lesions and disseminated intravascular coagulation syndrome occurred. For personal convenience, this patient was initially treated with fondaparinux followed by a new oral anticoagulant (rivaroxaban) before to return to the conventional VKA treatment.

CONCLUSION

The "seronegative" APS is a controversial concept reflecting the heterogeneity of antigenic targets for aPL. This diagnosis may be considered after a rigorous work-up, with the help of haemostasis laboratories testing new emerging aPL assays. In APS, the new anticoagulants represent an attractive option needing nevertheless prospective studies to evaluate their safety and efficacy. Lupus anticoagulant detection in patients treated by new oral anticoagulants is not easy by usually recommended coagulation tests.

Patients with Multiple Sclerosis and concomitant uveitis/periphlebitis retinae are not distinct from those without intraocular inflammation

Recent models of experimental autoimmune encephalomyelitis (EAE) have indicated that antigens co-expressed in the retina and uvea might be of pathogenetic relevance in Multiple Sclerosis (MS). We investigated the clinical spectrum and magnetic resonance imaging of 11 MS patients with concomitant uveitis, and determined the frequency of clinically silent intraocular inflammation in a prospective series of 50 patients. Two of the 11 patients had panuveitis, seven had anterior, and the remaining two had intermediate uveitis. The onset of uveitis preceded that of neurological symptoms by a mean of 8.5 years (range 1-20). None of the 50 MS patients studied prospectively by using slit lamp examinations and dilated funduscopy showed any evidence of uveitis but six patients had signs of retinal inflammation ("periphlebitis retinae"). Cranial MRI did not reveal "atypical" lesional distribution in MS patients with uveitis or periphlebitis retinae. No correlation between the type of MS and uveitis, or between the degree of neurological disability and the type of uveitis was found.

Overexpression of tumor necrosis factor-alpha produces an increase in lung volumes and pulmonary hypertension

Tumor necrosis factor (TNF)-alpha is a key proinflammatory cytokine that is thought to be important in the development of pulmonary fibrosis, whereas its role in pulmonary emphysema has not been as thoroughly documented. In the present study, TNF-alpha was overexpressed in alveolar type II cells under the control of the human surfactant protein C promoter. In this report, we further characterized the pulmonary abnormalities and provided a physiological assessment of these mice. Histopathology of the lungs revealed chronic inflammation, severe alveolar air space enlargement and septal destruction, and bronchiolitis. However, pulmonary fibrosis was very limited and only seen in the subpleural, peribronchiolar, and perivascular regions. Physiological assessment showed an increase in lung volumes and a decrease in elastic recoil characteristic of emphysema; there was no evidence of restrictive lung disease characteristic of pulmonary fibrosis. In addition, the mice raised in ambient conditions in Denver developed pulmonary hypertension. Gelatinase activity was increased in the lavage fluid from these lungs. These results suggest that in these mice TNF-alpha contributed to the development of pulmonary emphysema through chronic lung inflammation and activation of the elastolytic enzymes but by itself was unable to produce significant pulmonary fibrosis.

[Survey of infant mortality in Mirebalais, Haiti]

Infant mortality remains high in Haiti, at 74 deaths per 1,000 live births. In this study, we aimed to assess infant mortality in Mirebalais and to identify the associated risk factors. We carried out a census of pregnant women in Mirebalais, at the beginning of the study, over a three-week period. Twelve researchers visited the homes of the newborns to enroll the families in the study and to collect demographic data. Further visits were scheduled for two, four, six, nine and twelve months after birth. If the child died during this time, the investigator asked the mother about all the steps taken to prevent the death of the child, and an autopsy was carried out. The survey began on July 12 1994 and ended on December 31 1995. During that time, about 2,151 pregnant women were enrolled. Seven of these women died and 16 had abortions. In total, 2,069 children were born to the enrolled women. We enrolled 515 other children after birth or following referral by health workers or midwives. We therefore followed 2,584 children. We found that 10% of the mothers were aged between 15 and 19 years, 66.3% had had one to three pregnancies and 73% were entirely uneducated. The early neonatal mortality rate was 4.64 per 1,000 live births, late neonatal mortality was 6.96 per thousand and post-neonatal mortality was 45.6 per thousand live births. Diarrhea was responsible for 60% of the deaths and acute respiratory infections for 11%, these two causes accounting for 71% of the deaths of children aged 1 to 12 months. Thus, although infant mortality has decreased it remains high in Mirebalais, largely due to diarrhea and acute respiratory infections in the post-neonatal period.

Molecular cloning and functional expression of bovine spleen ecto-NAD+ glycohydrolase: structural identity with human CD38

Bovine spleen ecto-NAD(+) glycohydrolase, an archetypal member of the mammalian membrane-associated NAD(P)(+) glycohydrolase enzyme family (EC 3.2.2.6), displays catalytic features similar to those of CD38, i.e. a protein originally described as a lymphocyte differentiation marker involved in the metabolism of cyclic ADP-ribose and signal transduction. Using amino acid sequence information obtained from NAD(+) glycohydrolase and from a truncated and hydrosoluble form of the enzyme (hNADase) purified to homogeneity, a full-length cDNA clone was obtained. The deduced sequence indicates a protein of 278 residues with a molecular mass of 31.5 kDa. It predicts that bovine ecto-NAD(+) glycohydrolase is a type II transmembrane protein, with a very short intracellular tail. The bulk of the enzyme, which is extracellular and contains two potential N-glycosylation sites, yields the fully catalytically active hNADase which is truncated by 71 residues. Transfection of HeLa cells with the full-length cDNA resulted in the expression of the expected NAD(+) glycohydrolase, ADP-ribosyl cyclase and GDP-ribosyl cyclase activities at the surface of the cells. The bovine enzyme, which is the first 'classical' NAD(P)(+) glycohydrolase whose structure has been established, presents a particularly high sequence identity with CD38, including the presence of 10 strictly conserved cysteine residues in the ectodomain and putative catalytic residues. However, it lacks two otherwise conserved cysteine residues near its C-terminus. Thus hNADase, the truncated protein of 207 amino acids, represents the smallest functional domain endowed with all the catalytic activities of CD38/NAD(+) glycohydrolases so far identified. Altogether, our data strongly suggest that the cloned bovine spleen ecto-NAD(+) glycohydrolase is the bovine equivalent of CD38.

Analysis of tear proteins by one- and two-dimensional thin-layer iosoelectric focusing, sodium dodecyl sulfate electrophoresis and lectin blotting. Detection of a new component: cystatin C

BACKGROUND

Isoelectric focusing (IEF) of tear proteins has not yet been carried out in a satisfactory way. Two-dimensional (2D) electrophoresis, especially in the combination of IEF with SDS, is able to differentiate between proteins in detail. The purpose of this study was therefore to analyze tear proteins by 1D IEF alone and in combination with a 2D pattern, and by IEF followed by lectin staining.

METHODS

Ampholines, covering a broad range from pH 3 to pH 10, were applied. After IEF, semi-dry blotting and incubation with a group II lectin and two group V lectins was performed.

RESULTS

Tear proteins could be separated into 31 single bands. Tear-specific pre-albumin (TSPA), lactoferrin, sIgA, IgG and lysozyme were found to be main components. Isoelectric points (IEPs, pls) of all proteins separated were determined by comparison with IEF standards. 2D patterns of IEF and SDS electrophoresis were obtained for the main subunit components of lactoferrin, sIgA, TSPA, and lysozyme. An additional new component of considerable concentration was focused at pI 8.6 with a subunit MW of 14 kDa. With s-WGA a component at an IEP of 5.2 was visualized, representing transferrin. With SNA, lactoferrin stained as a sharp main band at pI 5.1 with three additional weaker bands at IEPs from 4.8 to 4.9. At IEPs between 4.4 and 6.1, multiple components of sIgA were stained with MAA. The sugar specificity of transferrin at pI 5.2 was beta-GlcNAc. Lactoferrin showed glycation with NANA-alpha-2-6-Gal or NANA-alpha-2-6-GalNAc, whereas the sugar specificity of sIgA was NANA-alpha-2-3-Gal.

CONCLUSIONS

The investigative strategy applied here, including IEF alone, in combination with SDS-electrophoresis, and SDS-electrophoresis followed by lectin staining proved to be a reproducible method for tear protein analysis of hitherto unexperienced capacity. Lectin-stained bands of native tear proteins are not uniformly glycated by one sugar residue, but show various sugar specificities. IgA as a whole molecule is specifically glycated with NANA-alpha-2-3-Gal.

Localization of components of glycinergic synapses during rat spinal cord development

The sequence of events leading to the chemical matching of presynaptic neurotransmitters and postsynaptic transmitter receptors is investigated here in vivo for the spinal glycine receptor (GlyR) by using immunocytochemical methods. In the ventral horn of adult rat spinal cord, GlyRs are only present at glycinergic postsynaptic differentiations where they are stabilized by the associated protein gephyrin. With quantitative confocal microscopy, we found that gephyrin is detected before GlyRs at embryonic day (E)13-E14 and at E15, respectively, inside the cytoplasm and at plasmalemmal loci. Around the time of birth, the number of cell surface gephyrin-immunoreactive (-IR) spots exceeds that of GlyR. They first match 10 days after birth. The densities of postsynaptic gephyrin- and GlyR-IR were quantified between birth and the adult stage with post-embedding immunogold staining. Immunostaining for gephyrin and GlyR was not detected in the extrasynaptic membrane. The density of staining in postsynaptic membrane increased progressively with development. The inhibitory amino-acid content of the presynaptic terminal boutons opposed to gephyrin-IR sites was also analyzed. In the newborn, postnatal day 10, and adult, more than 90% of these boutons were immunostained for glycine. As seen with serial sections, 38% and 51.2% of the terminals also contained gamma-aminobutyric acid (GABA) in neonate and adult, respectively. These data indicate that around the time of birth, most glycine-containing boutons, some also containing GABA, are opposed to gephyrin-IR postsynaptic densities, whereas GlyRs are not present. Our results suggest that gephyrin determines subsynaptic loci on the plasma membrane where GlyR will subsequently accumulate.

The "three delays" as a framework for examining maternal mortality in Haiti

Haiti has one of the highest rates of maternal mortality in the Caribbean. The "Three Delays" model proposes that pregnancy-related mortality is overwhelmingly due to delays in: (1) deciding to seek appropriate medical help for an obstetric emergency; (2) reaching an appropriate obstetric facility; and (3) receiving adequate care when a facility is reached. This framework was used to analyze a sample of 12 maternal deaths that occurred in a longitudinal cohort of pregnant Haitian women. Because of political upheavals in Haiti during the survey, these deaths are an underestimate of all deaths that occurred in the cohort. Family and friend interviews were used to obtain details about the medical and social circumstances surrounding each death. A delayed decision to see medical care was noted in eight of the 12 cases, whereas delays in transportation only appeared to be significant in two. Inadequate care at a medical facility was a factor in seven cases. Multiple delays were relevant in the deaths of three women. Family and friend interviews suggest that a lack of confidence in available medical options was a crucial factor in delayed or never made decisions to seek care. Expanding the coverage of existing referral networks, improving community recognition of obstetric emergencies, and improving the ability of existing medical institutions to deliver quality obstetric care, are all necessary. However, services will continue to be under-utilized if they are perceived negatively by pregnant women and their families. The current data thus suggest that improvements to Haiti's maternity care system which focus on reducing the third delay--that is, improving the quality and scope of care available at existing medical facilities--will have the greatest impact in reducing needless maternal deaths.

Dynamin genes Dnm1 and Dnm2 are located on proximal mouse chromosomes 2 and 9, respectively

Dynamins, microtubule-binding GTPases, are encoded by at least three genes in mammals. Two distinct gene-specific cDNAs were used to analyze the segregation of dynamin genes Dnm1 and Dnm2 in a mouse interspecies backcross. The nervous system-expressed gene Dnm1 was localized to Chr 2 between the genes for vimentin and nebulin, within a chromosomal region of conserved synteny to human chromosome 9q, consistent with the localization of the human dynamin-1 gene by FISH (see accompanying paper by Newman-Smith et al., 1997, Genomics 41:286-289). The ubiquitously expressed Dnm2 gene was found to be closely linked to the intercellular adhesion molecule-1 gene, Icam1, in a region with homologies to human chromosomes 19p, 8q, and 11q. Potential relations of both loci to disease genes are discussed.

Involvement of bovine spleen NAD+ glycohydrolase in the metabolism of cyclic ADP-ribose-mechanism of the cyclization reaction

We have shown that highly purified bovine spleen NAD+ glycohydrolase (NADase), known so far to catalyze the hydrolysis of the nicotinamide-ribose bond of NAD(P)+, was also able to convert NAD+ into cyclic ADP-ribose (cADPR) and to hydrolyze cADPR into ADP-ribose. The kinetic parameters measured for the cyclic ADP-ribose hydrolase activity seem to exclude that cADPR is a kinetically competent reaction intermediate in the NADase catalyzed conversion of NAD+ into ADP-ribose. The cyclase activity of bovine NADase was best evidenced by the transformation of NGD+ into cyclic GDP-ribose which was the major reaction product whereas, in contrast, cADPR accounted for less than 2% of the products formed. For the formation of cADPR we propose a reaction mechanism that is based on the partitioning of an oxocarbenium reaction intermediate between an intramolecular attack by the N1-position of adenine and an intramolecular reaction by a water molecule. Accordingly, the difference in cyclization between NAD+ and NGD+ is accounted for by the difference in reactivity of the N1 and N7 positions of the purine ring in these dinucleotides.

Mechanism of cyclization of pyridine nucleotides by bovine spleen NAD+ glycohydrolase

We have shown that bovine spleen NAD+ glycohydrolase (EC), purified to homogeneity, is a multifunctional enzyme. A time-dependent formation of cADPR from NAD+ that did not exceed 1.5-2% of the reaction products was measurable. The cyclase activity of this enzyme was, however, best evidenced by its transformation of NGD+ into cyclic GDP-ribose (cGDPR). The formation of the cyclic compound could be monitored spectroscopically (UV and fluorescence) and by high-performance liquid chromatography; the product ratio of cGDPR/GDP-ribose was 2:1. Bovine spleen NAD+ glycohydrolase is also able to hydrolyze cADPR (Muller-Steffner et al. (1994) Biochem. Biophys. Res. Commun. 204, 1279-1285); the kinetic parameters (V/Km) measured exclude, however, the possibility that cADPR is a kinetically competent reaction intermediate in the transformation of NAD+ into ADP-ribose. Experimental data indicating that NAD+ glycohydrolase-catalyzed hydrolysis and methanolysis of NA(G)D+ occurred at the expense of the formation of the cyclic compounds are in favor of a reaction mechanism involving the partitioning of a common oxocarbenium reaction intermediate between the different acceptors. Thus E.A(G)DP-ribosyl oxocarbenium intermediate can react according to i) intramolecular processes with the positions N-1 of adenine and N-7 of guanine to give cA(G)DPR as reaction products, and ii) intermolecular reactions with water (formation of A(G)DP-ribose) and methanol (formation of methyl A(G)DP-ribose). We attribute the marked difference in yield of cADPR and cGDPR to the intrinsic reactivity (nucleophilicity and positioning) of the purine N-positions that are involved in the cyclization reactions within the E.A(G)DP-ribosyl oxocarbenium complexes.

Arrested pregnancy syndrome in Haiti: findings from a national survey

This report describes findings from a national survey of pregnant women in Haiti regarding the social epidemiology of pedisyon (perdition), or "arrested pregnancy syndrome," a condition believed to be associated with infertility. Data collected on mortality of respondents' sisters were used to indirectly measure the prevalence of this culture-bound syndrome in the adult female population and to compare its distribution in urban and rural areas. Perdition appears to be a fairly common event that affects a large proportion of Haitian women. Reported cases of pedisyon were significantly higher in urban areas, which also differed from rural areas on respondent education, economic status, use of prenatal care, and fertility. No differences were found on sociodemographic, health, or fertility variables when women reporting perdition deaths were compared with women who reported other sister deaths. The utility and limitations of the proxy respondent method are discussed. Possible explanations for the higher rate of pedisyon among urban Haitian women are discussed, and suggestions are made for future research on arrested pregnancy syndrome.

Role of IL-7 in the shaping of the pulmonary gamma delta T cell repertoire

Gamma delta T cells bearing the canonical fetal-type V gamma 6/V delta 1 rearrangements are the predominant gamma delta T cells in the lungs of adult mice. In contrast, these V gamma 6/V delta 1 T cells are virtually absent in the pulmonary epithelia of nude mice. The intraepithelial dominance of gamma delta T cells that express this particular TCR is thought to result from a preferred thymic pathway of gene rearrangement and not from TCR-mediated positive selection. We now show that gamma delta T cell precursors in the lung epithelium of both euthymic and athymic neonatal mice generate this rearrangement in situ. In athymic mice, these clonotypes do not survive, but can be rescued in vitro and in vivo by the lymphokine IL-7.

Role of IL-7 in the shaping of the pulmonary gamma delta T cell repertoire

Gamma delta T cells bearing the canonical fetal-type V gamma 6/V delta 1 rearrangements are the predominant gamma delta T cells in the lungs of adult mice. In contrast, these V gamma 6/V delta 1 T cells are virtually absent in the pulmonary epithelia of nude mice. The intraepithelial dominance of gamma delta T cells that express this particular TCR is thought to result from a preferred thymic pathway of gene rearrangement and not from TCR-mediated positive selection. We now show that gamma delta T cell precursors in the lung epithelium of both euthymic and athymic neonatal mice generate this rearrangement in situ. In athymic mice, these clonotypes do not survive, but can be rescued in vitro and in vivo by the lymphokine IL-7.

Commitment and maintenance of the alpha beta and gamma delta T cell lineages

We have generated transgenic mice using a rearranged, functional TCR-gamma gene that lacks the C gamma 1 3' silencer element, together with a TCR-delta cDNA construct designed for expression in lymphoid cells. All transgenic mice that descended from nine founders expressed alpha beta T cells and elevated levels of gamma delta T cells at various ratios. This observation does not support the proposal that alpha beta T cells are generated from T precursors in which C gamma 1 genes have been repressed via the cis-acting 3' silencer element, but it supports the idea that lineage commitment occurs independently of TCR gene expression. In seven transgenic lines, despite the absence of the 3' C gamma 1 silencer on the gamma transgene, the transgenic TCR is expressed only in gamma delta and not in alpha beta T cells. In the other two lines, in addition to T cells that express either the alpha beta or gamma delta TCR, a substantial fraction of T cells expresses both alpha beta and gamma delta TCR. These two lines also carry the highest number of copies of TCR-gamma transgene. However, in general, there is no correlation between the copy number of the gamma transgene and the fraction of T cells expressing the gamma delta TCR. The implications of these data are discussed.

Commitment and maintenance of the alpha beta and gamma delta T cell lineages

We have generated transgenic mice using a rearranged, functional TCR-gamma gene that lacks the C gamma 1 3' silencer element, together with a TCR-delta cDNA construct designed for expression in lymphoid cells. All transgenic mice that descended from nine founders expressed alpha beta T cells and elevated levels of gamma delta T cells at various ratios. This observation does not support the proposal that alpha beta T cells are generated from T precursors in which C gamma 1 genes have been repressed via the cis-acting 3' silencer element, but it supports the idea that lineage commitment occurs independently of TCR gene expression. In seven transgenic lines, despite the absence of the 3' C gamma 1 silencer on the gamma transgene, the transgenic TCR is expressed only in gamma delta and not in alpha beta T cells. In the other two lines, in addition to T cells that express either the alpha beta or gamma delta TCR, a substantial fraction of T cells expresses both alpha beta and gamma delta TCR. These two lines also carry the highest number of copies of TCR-gamma transgene. However, in general, there is no correlation between the copy number of the gamma transgene and the fraction of T cells expressing the gamma delta TCR. The implications of these data are discussed.

Familial adenomatous polyposis: desmoid tumours and lack of ophthalmic lesions (CHRPE) associated with APC mutations beyond codon 1444

An earlier study has shown that FAP patients with mutations in codons 136-302 of the APC gene do not develop congenital hypertrophy of the retinal pigment epithelium (CHRPE), whereas those with mutations in codons 463-1387 regularly do. Here we present data on 36 patients from 20 families with mutations in codons 1445-1578. These patients lack CHRPE. Furthermore, with the exception of three prepubertal children all patients with mutations in codons 1445-1578 developed desmoid tumours. This relationship between certain extracolonic manifestations and site of the APC mutation points to a specific role of the APC protein in different tissues.

Homing and in situ differentiation of resident pulmonary lymphocytes

At birth, T lymphocytes which colonize the lung are mainly of the gamma delta subset, while alpha beta T cells predominate in the spleen. Thus, the lung is a preferred site for the homing of gamma delta T cells in the perinatal period. However, after birth, the pattern of V gamma gene usage among resident pulmonary lymphocytes (RPL) changes with age, from a predominance of V gamma 6 at birth to a predominance of V gamma 4 in older mice. The generation of the V gamma 6 fraction appears to be thymus dependent, since in athymic nude mice, the V gamma 6 population present at birth is replaced by V gamma 4 T cells. In the postnatal period, both RAG-1 and RAG-2 genes are expressed at high levels in the RPL population. TCR bearing cells are among those that express RAG genes, indicating that maturation of T cells takes place in this organ. In addition, transfer experiments reveal that lymphoid precursors are present in the lung. The stage of differentiation of these precursors will be characterized in future studies. The data presented here indicate that pulmonary T lymphocytes are derived from both migrants of thymic origin and from precursors which have undergone differentiation and selection in the lung. The population that is generated in situ and that has not been selected in the thymus may include cells that are typical for the pulmonary environment.

Antigen-dependent selection of T cells that are able to efficiently regulate free cytoplasmic Ca2+ levels

In T helper cells, the process of memory acquisition is reflected in the expression of phenotypic markers. However, little is known regarding the functional changes that occurred in T helper cells selected after a primary Ag-specific response. We now present data that indicate that such T helper cells acquire the ability to down-regulate high concentrations of free cytoplasmic Ca2+. This property renders them resistant to intense inductive stimuli, such as high concentrations of ionomycin. The accumulation of cells that display this ability parallels the progressive proliferative enrichment of Ag-specific T cells and correlates with the surface expression of the CD45RB(low) isoform. As previously shown, persistent high levels of cytoplasmic Ca2+ are responsible for death via apoptosis in virgin T cells. In contrast, the ability to regulate cytosolic Ca2+ allows survival and clonal expansion. We suggest that memory T cells behave differently from virgin T cells when interacting with Ag-presenting B cells (as reported by others) because they have acquired this new physiologic property. Ag-presenting B cells deliver an intense stimulatory signal to T cells because of a high multiplicity of cognate interactions. Thus, Ag-driven T cell proliferation results in the selection of "resistant" T helper cells that can be successfully stimulated by memory B cells. In contrast, naive T cells, which cannot modulate high levels of cytosolic Ca2+, are deleted as a consequence of Ag presentation by B cells.

Antigen-dependent selection of T cells that are able to efficiently regulate free cytoplasmic Ca2+ levels

In T helper cells, the process of memory acquisition is reflected in the expression of phenotypic markers. However, little is known regarding the functional changes that occurred in T helper cells selected after a primary Ag-specific response. We now present data that indicate that such T helper cells acquire the ability to down-regulate high concentrations of free cytoplasmic Ca2+. This property renders them resistant to intense inductive stimuli, such as high concentrations of ionomycin. The accumulation of cells that display this ability parallels the progressive proliferative enrichment of Ag-specific T cells and correlates with the surface expression of the CD45RB(low) isoform. As previously shown, persistent high levels of cytoplasmic Ca2+ are responsible for death via apoptosis in virgin T cells. In contrast, the ability to regulate cytosolic Ca2+ allows survival and clonal expansion. We suggest that memory T cells behave differently from virgin T cells when interacting with Ag-presenting B cells (as reported by others) because they have acquired this new physiologic property. Ag-presenting B cells deliver an intense stimulatory signal to T cells because of a high multiplicity of cognate interactions. Thus, Ag-driven T cell proliferation results in the selection of "resistant" T helper cells that can be successfully stimulated by memory B cells. In contrast, naive T cells, which cannot modulate high levels of cytosolic Ca2+, are deleted as a consequence of Ag presentation by B cells.

Selection of pulmonary CD4-, CD8-, alpha beta+ T cells expressing V beta 8 T cell receptors

The double negative (CD4-CD8-) alpha beta+ T cells constitute about 20% of all alpha beta+ T cells in murine lungs. We find that in BALB/c mice 60% of the double negative alpha beta+ pulmonary T cells express receptors of the V beta 8 family whereas only 33% of single positive (CD4+/CD8+) pulmonary T cells express V beta 8. However, in C57BL/6 mice, equal frequencies (25%) of double negative and single positive alpha beta+ pulmonary T cells express V beta 8. The high frequency of double negative V beta 8+ pulmonary T cells is dominantly inherited in (C57BL/6 X BALB/c) F1 offsprings. Further studies exclude the involvement of classic MHC region genes in determining the level of V beta 8 usage among double negative pulmonary T cells. Upon exposure to mycobacterial antigens, double negative alpha beta+ pulmonary T cells are co-enriched in vitro in parallel with gamma delta+ T cells.

Social and psychological costs of preventive child health services in Haiti

Much of the research on determinants of health service utilization has focused on economic and cognitive variables which influence preventative health behavior. Our ethnographic study of maternal perceptions of the barriers and incentives to immunization use in Haiti underscores the importance of 'hidden' social and psychological costs of utilization, such as embarrassment, fear, child care difficulties, and competing demands on maternal time. Findings from focus group interviews with mothers, individual interviews with health care providers, and observation at health posts identified five categories of maternal factors (competing priorities, low motivation, socioeconomic constraints, fears about health or social consequences, knowledge and folk beliefs) and five categories of system factors (accessibility, acceptability, availability, accommodation, affordability) which can deter immunization completion. The discussion focuses on how these factors influence maternal decision-making regarding use of preventive child health services. More attention is needed on the psychosocial costs of health behavior in developing country settings.

Chromosomal mapping in the mouse of eight K(+)-channel genes representing the four Shaker-like subfamilies Shaker, Shab, Shaw, and Shal

The four Shaker-like subfamilies of Shaker-, Shab-, Shaw-, and Shal-related K+ channels in mammals have been defined on the basis of their sequence homologies to the corresponding Drosophila genes. Using interspecific backcrosses between Mus musculus and Mus spretus, we have chromosomally mapped in the mouse the Shaker-related K(+)-channel genes Kcna1, Kcna2, Kcna4, Kcna5, and Kcna6; the Shab-related gene Kcnb1; the Shaw-related gene Kcnc4; and the Shal-related gene Kcnd2. The following localizations were determined: Chr 2, cen-Acra-Kcna4-Pax-6-a-Pck-1-Kras-3-Kcn b1 (corresponding human Chrs 11p and 20q, respectively); Chr 3, cen-Hao-2-(Kcna2, Kcnc4)-Amy-1 (human Chr 1); and Chr 6, cen-Cola-2-Met-Kcnd2-Cpa-Tcrb-adr/Clc-1-Hox-1.1-Myk - 103-Raf-1-(Tpi-1, Kcna1, Kcna5, Kcna6) (human Chrs 7q and 12p, respectively). Thus, there is a cluster of at least three Shaker-related K(+)-channel genes on distal mouse Chr 6 and a cluster on Chr 2 that at least consists of one Shaker-related and one Shaw-related gene. The three other K(+)-channel genes are not linked to each other. The map positions of the different types of K(+)-channel genes in the mouse are discussed in relation to those of their homologs in man and to hereditary diseases of mouse and man that might involve K+ channels.

In Mls-1a mice, fetal-type beta-gene rearrangements are frequent among self-anergic V beta 6 T cells

T lymphocytes generated in the fetal and neonatal period are characterized by T cell receptor (TCR) gene rearrangements that lack N region nucleotides (fetal-type TCR). Using fetal-type TCR as a lineage marker, we show that such T cells are long-lived and persist in the periphery of adult mice. Moreover, in both neonatal and adult environments, upon encounter with self-antigens, they are less likely to be deleted. Inefficient clonal deletion could be due to the intrinsic properties of the T cells generated during this period, or to yet unknown properties of the perinatal thymus. Such anergic T cells constitute a subset that can further expand in vivo in an antigen-independent fashion, leaving open the possibility for self-aggression under the appropriate triggering conditions.

Predictive diagnosis in familial adenomatous polyposis: evaluation of molecular genetic and ophthalmologic methods

Familial adenomatous polyposis (FAP) is an autosomal-dominant precancerous condition characterized by the appearance of hundreds to thousands of colorectal polyps. The responsible gene (APC) has been mapped and identified. The cancer prevention policy for persons at risk (children and sibs of FAP patients) implies an early diagnosis of the disease. A presymptomatic diagnosis allows to limit the regular rectosigmoidoscopic examination to those persons having inherited the disease gene. Presymptomatic diagnosis can be achieved by molecular genetic methods (direct and indirect genotype analysis) and by funduscopic examination of retinal pigment anomalies that are characteristic for FAP. The aim of this study was to examine the power of the molecular genetic and ophthalmologic methods for presymptomatic diagnosis in FAP. For this purpose 60 FAP families with 171 persons at risk were examined. By direct mutation analysis a presymptomatic diagnosis was achieved in 32% of the persons at risk; indirect genotype analysis was possible in 88% of the families in which more than one FAP patient was available. The ophthalmologic examination allowed a presymptomatic conclusion in 79% of the persons at risk. In no case there was a discrepancy in the results between the methods applied. The ophthalmologic presymptomatic test is useful especially in families where the index patients has a new mutation in the APC gene that has not been identified.

The presence of an endogenous murine leukemia virus sequence correlates with the peripheral expansion of gamma delta T cells bearing the BALB invariant delta (BID) T cell receptor delta

gamma delta T cells participate in immune responses during viral, bacterial, and parasitic infections. However, it is not clear whether they recognize antigens produced by pathogens, or are actually reactive to self-ligands generated during the course of infection. In this paper, we report that the presence of the self-ligand that selectively expands a subset of gamma delta T cells correlates with the presence of an endogenous murine leukemia virus (MuLV) in inbred strains of mice. The implications of this observation for gamma delta T cell specificity and function is discussed.

Vitamin A supplementation and increased prevalence of childhood diarrhoea and acute respiratory infections

There is uncertainty over whether vitamin A supplementation reduces morbidity among children with subclinical deficiency of the vitamin. Hence a double-blind, placebo-controlled trial of the effect of vitamin A supplementation on childhood morbidity was conducted among 11,124 children aged 6-83 months in the northwest of Haiti. After a random start, children were sequentially assigned by household units to receive either megadose vitamin A or placebo in three distribution cycles 4 months apart. 2 to 8 weeks after each administration of the vitamin A and placebo capsules, indicators of childhood morbidity were reassessed through interviews conducted in the homes of participating families. The vitamin A group was found to have an increased 2-week prevalence of all symptoms and signs of childhood morbidity assessed, including diarrhoea (rate ratio [RR] = 1.09, 95% confidence interval 1.05-1.14), rhinitis (RR = 1.02, 95% confidence interval 1.00-1.04), cold/flu symptoms (RR = 1.04, 95% confidence interval 1.01-1.06), cough (RR = 1.07, 95% confidence interval 1.03-1.11), and rapid breathing (RR = 1.18, 95% confidence interval 1.09-1.27). The study shows an increased 2-week prevalence of diarrhoea and the symptoms of respiratory infections after vitamin A supplementation.

Patterns of responsiveness of T cell lines and thymocytes reveal waves of specific activity in the post-natal murine thymus

Antibody binding of CD3, CD4, or CD8 molecules can induce cytoplasmic calcium mobilization in T lymphocytes, usually interpreted as indicating signal transduction. Using such assays, in a CD4+ CD8+ thymocyte line and its single positive progeny we have identified characteristic patterns of responsiveness that are reproducible in vivo in a subpopulation of newborn 'double positive' thymocytes but virtually absent in adult thymuses. In particular, these cells appear to be high responders to the binding of anti-CD3 F(ab)'2 fragments. We have followed the presence of such highly responsive thymocytes in the perinatal period and the first 15 days of life. Intriguingly, these cells populate the newborn thymus in three distinct waves. Such patterns of responsiveness may define early 'selectable' thymocytes.

Selective proliferation of gamma delta T lymphocytes exposed to high doses of ionomycin

The alpha beta T cell repertoire is primarily shaped in the thymus. However, extrathymic positive selection has been demonstrated for many gamma delta T cell clonotypes. This latter type of selection is the result of a peripheral clonal expansion which could be facilitated by special physiological properties of gamma delta T cells, distinguishing them from most alpha beta T cells. In studying the behavior of T cells under conditions of polyclonal activation, we noticed a differential sensitivity between alpha beta and gamma delta T cells to strong stimulatory signals. When induced with high doses of ionomycin, a large fraction of peripheral gamma delta T cells and a small fraction of alpha beta T cells are able to proliferate exponentially while most alpha beta T cells die. This phenomenon appears to be related to intracellular regulation of high concentrations of cytosolic Ca2+. The ability to proliferate under strong stimulatory conditions is a striking feature of many peripheral gamma delta T cells but not of gamma delta thymocytes. In general, T cells selected in the periphery by clonal expansion might be characterized by resistance to strong stimuli and typically, by their ability to "handle" higher concentrations of free cytoplasmic calcium.

Selective proliferation of gamma delta T lymphocytes exposed to high doses of ionomycin

The alpha beta T cell repertoire is primarily shaped in the thymus. However, extrathymic positive selection has been demonstrated for many gamma delta T cell clonotypes. This latter type of selection is the result of a peripheral clonal expansion which could be facilitated by special physiological properties of gamma delta T cells, distinguishing them from most alpha beta T cells. In studying the behavior of T cells under conditions of polyclonal activation, we noticed a differential sensitivity between alpha beta and gamma delta T cells to strong stimulatory signals. When induced with high doses of ionomycin, a large fraction of peripheral gamma delta T cells and a small fraction of alpha beta T cells are able to proliferate exponentially while most alpha beta T cells die. This phenomenon appears to be related to intracellular regulation of high concentrations of cytosolic Ca2+. The ability to proliferate under strong stimulatory conditions is a striking feature of many peripheral gamma delta T cells but not of gamma delta thymocytes. In general, T cells selected in the periphery by clonal expansion might be characterized by resistance to strong stimuli and typically, by their ability to "handle" higher concentrations of free cytoplasmic calcium.

[Effect of constitutional ligament laxity and physical stress on development of patellar tip syndrome]

Studies were performed in order to obtain information on the pathogenesis of patellar tip syndrome (PTS). Using a finger hyperextensiometer, ligamental laxity tests were performed on athletes, non-athletes and controls. Ninety-eight PTS patients who did not indulge regularly in sports, 39 patients from the German federal volleyball league, and 400 healthy controls were examined. No difference in the extensibility of ligaments was found between the patients from the group of competitive athletes and the controls. However, a significantly increased extensibility of the finger joints was found in all age and sex groups with "spontaneous" PTS. The authors conclude that 1) constitutional laxity of the ligaments is a key predisposing factor for PTS, and 2) PTS is triggered by physical stress. Susceptibility to microtrauma at the insertion of the patellar ligament is a function of the constitutional strength of the ligaments.

Influence of free radical scavengers on myeloperoxidase activity and lipid peroxidation in acute skin grafts

Activated neutrophil granulocytes are an important source of oxygen free radicals in acute skin grafts. Lipid peroxidation and immigration of PMNs, indicating inflammatory mechanisms, affect each other to a variable extent. The effect of the scavengers allopurinol and alpha-D-tocopherol on both lipid peroxidation and neutrophilic infiltration was investigated. A possible mechanism for the superior effect of allopurinol compared to vitamin E was discussed.

Extrathymic positive selection of gamma delta T cells. V gamma 4J gamma 1 rearrangements with "GxYS" junctions

Neither function nor Ag recognition properties of gamma delta T cells are well understood yet. A TCR gamma-chain family, characterized by distinct N region sequences that converge in coding for a "GxYS" VJ junctional sequence, appears late in ontogeny among highly diversified V gamma 4J gamma 1C gamma 1 chains of C57BL/6 and BALB/c mice. The glycine and serine codons are of germline V gamma 4 and J gamma 1 origin, respectively, whereas the N region consists of a variable amino acid residue x, followed by an invariant tyrosine Y. The high expression of V gamma 4 xYJ gamma 1C gamma 1 in the lung of BALB/c mice compared to that of C57BL/6 is apparently due to a novel pattern of strain-dependent positive selection which, unlike for alpha beta TCR, operates extrathymically. This type of selection seems to be determined by strain specific polymorphic ligands encoded outside of the classical H-2 region.

Extrathymic positive selection of gamma delta T cells. V gamma 4J gamma 1 rearrangements with "GxYS" junctions

Neither function nor Ag recognition properties of gamma delta T cells are well understood yet. A TCR gamma-chain family, characterized by distinct N region sequences that converge in coding for a "GxYS" VJ junctional sequence, appears late in ontogeny among highly diversified V gamma 4J gamma 1C gamma 1 chains of C57BL/6 and BALB/c mice. The glycine and serine codons are of germline V gamma 4 and J gamma 1 origin, respectively, whereas the N region consists of a variable amino acid residue x, followed by an invariant tyrosine Y. The high expression of V gamma 4 xYJ gamma 1C gamma 1 in the lung of BALB/c mice compared to that of C57BL/6 is apparently due to a novel pattern of strain-dependent positive selection which, unlike for alpha beta TCR, operates extrathymically. This type of selection seems to be determined by strain specific polymorphic ligands encoded outside of the classical H-2 region.

Dominant expression of the T cell receptor BALB invariant delta (BID) chain in resident pulmonary lymphocytes is due to selection

During ontogeny, the T cell receptor BALB invariant delta (BID) chain (Sim, G. -K. and Augustin, A., Cell 1990. 61:397) is generated in C57BL/6 fetal thymocytes at levels similar to those detected in BALB/c mice. Hence, the dominance of BID observed among resident pulmonary lymphocytes of BALB/c and of (BALB/c x C57BL/6) F1 and its absence in C57BL/6 mice is due to positive selection and peripheral expansion rather than to the inability of C57BL/6 mice to generate this particular rearrangement.