Prolonged gene knockdown in the tsetse fly Glossina by feeding double stranded RNA.

Reverse genetic studies based on RNA interference (RNAi) have revolutionized analysis of gene function in most insects. However the necessity of injecting double stranded RNA (dsRNA) inevitably compromises many investigations particularly those on immunity. Additionally, injection of tsetse flies often causes significant mortality. We demonstrate, at transcript and protein level, that delivering dsRNA in the bloodmeal to Glossina morsitans morsitans is as effective as injection in knockdown of the immunoresponsive midgut-expressed gene TsetseEP. However, feeding dsRNA fails to knockdown the fat body expressed transferrin gene, 2A192, previously shown to be silenced by dsRNA injection. Mortality rates of the dsRNA fed flies were significantly reduced compared to injected flies 14 days after treatment (Fed: 10.1%+/- 1.8%; injected: 37.9% +/- 3.6% (Mean +/- SEM)). This is the first demonstration in Diptera of gene knockdown by feeding and the first example of knockdown in a blood-sucking insect by including dsRNA in the bloodmeal.

Risk of schizophrenia in adults born after obstetric complications and their association with early onset of illness: a controlled study.

OBJECTIVE: To determine whether obstetric complications occur to excess in the early histories of individuals who go on to develop schizophrenia when compared with controls, and to seek clinical correlates of any such excess. DESIGN: Contemporaneous maternity hospital records were identified and extracted verbatim, and these extracts evaluated for obstetric complications by two independent assessors who were blind to subjects' status. SUBJECTS: 65 patients having an ICD-9 diagnosis of schizophrenia, the records of the previous same sex live birth being deemed to be those of a control subject. MAIN OUTCOME MEASURE: Presence of one or more obstetric complications recorded in maternity notes of patients and controls. RESULTS: When two recognised scales for specifying obstetric complications were used the patients with schizophrenia were significantly more likely than controls to have experienced at least one obstetric complication (odds ratio 2.44, 95% confidence interval 1.08 to 6.03). Patients also showed a greater number and severity of and total score for obstetric complications, fetal distress being the only complication to occur to significant individual excess (present in five (8%) patients, absent in controls). There was a marked sex effect, male patients being more vulnerable (odds ratio 4.24, 1.39 to 12.90) to such complications. Obstetric complications in patients were unrelated to family history or season of birth but were associated with a significantly younger age at onset of illness (mean difference--4.5 years,--1.2 to--7.8 years). CONCLUSIONS: Patients with schizophrenia, particularly males, have an excess of obstetric complications in their early developmental histories, and such complications are associated with a younger age at onset of their disease. Though the data are not conclusive, they also suggest that obstetric complications may be secondary to yet earlier events.

Addiction and temporary certification. A proposed change to legislation and it's possible implication for clinical practice.

The Mental Treatment Act (1945) is currently undergoing review to enable Ireland to meet it's international obligations. The Green Paper on Mental Health (1992) makes a number of suggestions regarding this. One such is the deletion of Addiction as sufficient grounds for involuntary admission to a psychiatric hospital or unit. This study looked at the possible impact such a proposal might have on the doctor's clinical choice in the management of addiction. The casenotes and temporary certificates of 191 involuntary admissions to St. Brendan's Hospital were examined. 9 cases (4.7%) were admitted for the direct effect of addiction, i.e., intoxication or uncomplicated withdrawal. The conclusion of this study is that the deletion of the addiction criterion from future mental health legislation would, in itself, have little impact on the number of committals. This is because the majority of those with evidence of Substance Abuse have a concurrent disorder that would be covered by the remaining criteria.

Committal procedures in Ireland.

The study aims to describe current committal practice in an Irish public psychiatric service and to establish the role of 'dangerousness' in determining practice. A six month retrospective review was undertaken using casenotes and original temporary forms of all patients committed to St Brendan's Hospital, Dublin within a six month period in 1990. A total of 136 cases were examined. In 65% of cases the application for detention was initiated by a spouse or relative. The recommending physician was identified as a General Practitioner in 80% of cases, although most were locum GP's. The number of male and female patients were almost equal. There was a wide age range with the largest group (42%) in the range 26-40 years. Previous contact with the psychiatric service was found in 89% of cases. There was a wide range of diagnoses with the largest category (56%) suffering from schizophrenia. Of those not admitted with alcohol or drug related illness 66% showed evidence of acute psychotic symptoms. Length of admission was relatively short with 84% of patients being discharged within three months. A total of 43% showed evidence of being a danger to themselves or others. Significant differences were found between these patients and the non-dangerous group, the latter being more likely to be older and to suffer from a major psychotic illness. These findings indicate that a committal law based purely on 'dangerousness' criteria would be likely to significantly affect committal practice in Ireland. These findings are discussed in relation to proposed changes in mental health legislation in Ireland.

Some observations on the preference deficits produced by lateral preoptic lesions in the rat.

Following water drprivation, rats with lateral preoptic (LPO) damage lose the normal preference for glucose solutions. Food deprivation reinstates the preference. This dependency is specific to sweet-tasting fluids, and the deficit persists even if thirst is alleviated prior to the preference test. Such rats will drink sweet solutions in response to intravascular fluid depletion, but they are deficient in response to sweet solutions under nondeprived conditions. This last finding in particular suggests that hunger and palatability, as determinants of the response to sweet solutions, may be dissociated by LPO damage.

Seroprevalence study of Hantavirus infection in the community based population.

The genus Hantavirus, family Bunyaviridae, comprise at least 20 distinct viruses. Ten of these have been linked to specific human diseases. Hemorrhagic fever with renal syndrome has been recognized since the 1950s. Hantavirus pulmonary syndrome was recognized in the United States in 1993. Epizootiologic studies of Norway rats in the Baltimore area have shown that rodent infections with hantaviruses are common and geographically widespread with prevalence reaching 44% in tested rat populations. These viruses are antigenically related to the Seoul virus. Hantavirus infections in humans occur through transmission from a rodent reservoir, primarily by inhalation of virus laden rodent excreta. There is no evidence to support person-to-person transmission of any known Hantavirus. To establish the prevalence of Hantavirus infections in humans in the Baltimore area we collected sera from 1,212 persons attending a community based health care system. These were tested for antibodies against three reference Hantavirus strains: Hantaan (HTN), Seoul (SEO), and Convict Creek (HN017). HN017 was chosen to represent the SinNombre (SN-like) strains of Hantavirus. Sera from nine patients were positive to Hantavirus specific antibodies, HTN, and SEO by Enzyme Linked Imuno Sorbent Assay (ELISA). No sera were positive for HN017 antigen. All sera that were positive for HTN and SEO were tested by western blot for HTN. All nine sera were confirmed positive by western blot. This suggests that unrecognized infections with Hantaan or Seoul-like viruses occur in the Baltimore area in humans, although the prevalence rate in humans is low (0.74%). Epidemiologic monitoring may be warranted to establish the health implications of these infections.

Albumin synthesis rates in cirrhosis: correlation with Child-Turcotte classification.

Albumin-synthesis rates were measured in nine patients with stable cirrhosis and compared with those of eight healthy volunteers by means of a new technique using stable isotopes. Four grams of L-[1-13C]leucine was injected over 10 min, and blood samples were drawn at intervals. Serum free [13C]leucine enrichment, taken to be the precursor for albumin synthesis, and 13C enrichment of leucine in albumin, isolated with differential solubility in absolute ethanol from trichloracetic acid-precipitated serum proteins, were measured on mass spectrometry. Albumin synthesis, expressed as a fractional rate, was 7.9% +/- 0.3%/day in the controls and 7.9% +/- 1.1%/day in the cirrhotic patients. Albumin synthesis, expressed as an absolute rate, was lower in the cirrhotic group (cirrhotic, 119 +/- 17 mg/kg/day; controls, 146 +/- 8 mg/kg/day), but because of the relatively small number of patients the difference was not significant. However, the absolute rate of albumin synthesis significantly correlated with the Child-Turcotte score (p = 0.024) and its Pugh modification (p = 0.027). The rate of albumin synthesis also correlated with serum phenylalanine concentration but not with serum albumin concentration and intravascular albumin mass or with other clinical indexes of liver function or integrity when taken separately. However, the significant correlation between albumin synthesis and Child score suggests that albumin synthesis might be useful for the clinical judgment of patients with cirrhosis.

Season of birth in schizophrenia. Evidence for confinement of an excess of winter births to patients without a family history of mental disorder.

Although it is well recognised that schizophrenic patients are more often born in winter, the significance of this finding remains obscure. Data relating to season of birth and family history were analysed for 561 patients with an ICD-9 diagnosis of schizophrenia. Patients with no family history of any psychiatric disorder group were significantly more likely to be born in winter than patients with a first-degree relative affected by schizophrenia. In comparison with normal population controls, only those without a family history exhibited a significant excess of winter births, suggesting an environmental factor of greater aetiological significance in these patients.

Absence of platelet CD40L identifies patients with X-linked hyper IgM syndrome.

CD40 ligand (CD40L), a membrane protein expressed on activated T cells, plays a pivotal role in B cell proliferation and differentiation. Mutations in the CD40L gene are associated with a rare immunodeficiency state, X-linked hyper IgM syndrome (XLHIGM). Recently, platelets have been described as capable of expressing CD40L within minutes of stimulation. We have developed a rapid technique to determine expression of CD40L on activated platelets by flow cytometry in whole blood. We have demonstrated that this technique is useful in neonatal screening, in rapid diagnosis and in determining reconstitution by donor bone marrow post-transplantation.

Immunological and genetic analysis of 65 patients with a clinical suspicion of X linked hyper-IgM.

BACKGROUND: X linked hyper-IgM (XHIM) is a primary immunodeficiency caused by mutations in the tumour necrosis factor superfamily 5 gene, TNFSF5, also known as the CD40 ligand (CD40L) gene. Patients often present with recurrent infections, and confirmation of a diagnosis of XHIM enables appropriate therapeutic interventions, including replacement immunoglobulin, antibiotics, and bone marrow transplantation. AIM: To review and optimise the institution's diagnostic strategy for XHIM. METHOD: Samples from 65 boys were referred to this centre for further investigation of suspected XHIM. The results, which included a flow cytometric whole blood assay for CD40L expression followed by mutation analysis in selected patients, were reviewed. RESULTS: Twenty one patients failed to express CD40L and TNFSF5 mutations were found in 20 of these patients. In contrast, no TNFSF5 mutations were found in 16 patients with weak expression of CD40L. Interestingly, one quarter of patients with confirmed XHIM who had TNFSF5 mutations had low concentrations of IgG, IgA, and IgM. Most of the remaining patients with XHIM had the classic pattern of normal or raised IgM with low concentrations of IgA and IgG. CONCLUSIONS: This study demonstrates the usefulness of the whole blood staining method as a rapid screen to select patients for subsequent TNFSF5 mutation analysis, and shows the benefits of a unified protein/genetic diagnostic strategy.

Intra-amniotic inflammation in human gastroschisis: possible aetiology of postnatal bowel dysfunction.

OBJECTIVE: To assess amniotic fluid for evidence of an inflammatory exudate in association with fetal gastroschisis. SETTING: University College Hospital, London and Institute of Child Health, London. SAMPLE: Samples of amniotic fluid in the third trimester from pregnant women with a diagnosis of fetal gastroschisis (n = 10) and from a control group (n = 10) with a normal fetus. METHODS: Cytological analysis of the fluid was performed. Flow cytometry was performed on the amniotic fluid using antibodies for the myeloid cell antigen CD15, the leucocyte beta integrin CD11b/CD18 and CD3, CD19, CD56 and CD25. Tumour necrosis factor alpha and interleukin-8 levels were assayed in the amniotic fluid. RESULTS: An acute inflammatory exudate, composed predominantly of neutrophil polymorphs and mononuclear cells, was found in the amniotic fluid in fetal gastroschisis but not in control cases. When amniotic fluid samples from cases of fetal gastroschisis were stained with CD15, analysis by flow cytometry showed a clear positive population. This CD15 population showed markedly elevated levels of CD11b. No distinct population of CD15 positive cells was seen in amniotic fluid samples examined from the control group. No staining was seen with antibodies to CD3, CD19, CD56 or CD25 in amniotic fluid obtained from either group. There was no significant difference between tumour necrosis factor alpha levels measured in the amniotic fluid of cases of fetal gastroschisis (median 102 pg/mL; range 20-340) and those of the control group (140 pg/mL; range 20-548) (P = 0.1). The levels of interleukin-8 were markedly elevated in the amniotic fluid of cases of fetal gastroschisis (median 6320 pg/mL; range 4732-13,800) compared with the control group (median 1738 pg/mL; range 623 2861;) (P < 0.01). CONCLUSION: Human fetal gastroschisis is associated with an inflammatory exudate in the amniotic fluid which may have implications for postnatal bowel function.