Mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) in a Donegal kindred--clinical features and molecular genetic analysis

A 19 year old female with a background history of migraine, sensorineural deafness and recent personality change developed a parieto-occipital cerebral infarct. Investigations revealed altered lactate to pyruvate ratios, ragged red fibres in muscle and an A-G point mutation at position 3243 in mitochondrial DNA. Subsequent clinical and molecular genetic analysis of 14 family members in three generations identified 12 affected individuals, two of whom were asymptomatic. Maternal inheritance was confirmed. MEALS is an important but under recognised cause of stroke and seizures in the young. There is insufficient data available to determine if the treatment of asymptomatic individuals retards the onset or reduces the severity of stroke.

Differential in vivo activation of the class II and class III snRNA genes by the POU-specific domain of Oct-1

Many snRNA genes contain binding sites for the ubiquitous transcription factor Oct-1. In vitro studies have shown that this factor potentiates binding of an essential transcription factor (PTF) to the proximal sequence element (PSE) of snRNA genes, and activates transcription. Using Gal4 fusion proteins, I show here that the POU-specific region of the DNA-binding domain of Oct-1 is sufficient both to potentiate PTF binding in vitro and to transactivate pol II- and pol III-dependent snRNA genes in vivo . A single amino acid change in this domain abrogates both activation and interaction with PTF. The N- and C-terminal regions of Oct-1 also activate transcription of both classes of snRNA genes. Wild-type levels of Pol II-dependent U2 expression require all activation domains, whereas efficient activation of the pol III-dependent 7SK and U6 genes is effected by the POU-specific domain alone. These results indicate that contacts between PTF and amino acids in the POU-specific domain of Oct-1 are critical for efficient transactivation of snRNA genes in vivo. The POU-specific domain of Oct-2A also activates these genes, but the N- and C-terminal domains are relatively inactive.

Thalamic NMDA receptors modulate inflammation-produced hyperalgesia in the rat

The effects of inhibition of thalamic NMDA receptor function and synthesis on thermal and mechanical hyperalgesia induced by hindlimb intraplantar injection of carrageenan in the rat were studied in the 'acute' phase (within 3-5 h) and the 'subacute' phase (24 h) after carrageenan administration. Blockade of NMDA receptors was produced by intrathalamic injection of D,2-amino-5-phosphonovaleric acid (D-APV) and NMDA receptor synthesis was decreased (or not) by pretreatment of rats with intrathalamic (hindlimb representation area) injections of antisense, sense or missense oligodeoxynucleotides (ODNs) directed against the NR1 subunit of the NMDA receptor complex. Treatment with D-APV, but not saline, in the contralateral (but not ipsilateral) thalamus significantly reduced both the acute thermal and mechanical hyperalgesia in the injected paw; these same rats demonstrated significantly less thermal and mechanical hyperalgesia in the sub-acute phase than rats that had received saline or D-APV in the ipsilateral thalamus. None of the treatments had any effect on withdrawal responses of the uninjected hindpaw. Rats pretreated with NR1 sense or missense ODNs developed both thermal and mechanical hyperalgesia that was equivalent in magnitude and duration to rats that received intrathalamic saline injections. In contrast, rats pretreated with NR1 antisense ODN did not develop either acute or subacute thermal hyperalgesia; they developed less mechanical hyperalgesia than saline, sense or missense ODN-treated rats. Antisense ODN-treated rats also displayed a decrease in the number of thalamic NMDA receptors as determined by receptor binding assay. These results suggest an involvement of thalamic NMDA receptors in the development and maintenance of hyperalgesia associated with neurogenic inflammation in a model of tonic pain.

HIV-induced T cell syncytia are self-perpetuating and the primary cause of T cell death in culture

Prior studies suggested that induced fusion in T cell cultures infected with syncytium-inducing HIV was not the primary cause of T cell death. However, these studies failed to assess the contribution of fusion in terms of syncytium volume, rather than syncytium frequency. This question has been reassessed by monitoring the frequency, volume, rate of growth, longevity, p24 production, viral budding, and self-propagating ability of syncytia in HIV-infected SUP-T1 cell cultures and individually isolated syncytia seeded in uninfected SUP-T1 cell cultures. The results demonstrate that in these cultures syncytium formation is the principal mechanism of T cell death, syncytia are the main source of virus production, and both virus production and syncytium longevity are independent of syncytium size, but dependent on syncytium age, suggesting that both are programmed events.

HIV-induced T cell syncytia are self-perpetuating and the primary cause of T cell death in culture

Prior studies suggested that induced fusion in T cell cultures infected with syncytium-inducing HIV was not the primary cause of T cell death. However, these studies failed to assess the contribution of fusion in terms of syncytium volume, rather than syncytium frequency. This question has been reassessed by monitoring the frequency, volume, rate of growth, longevity, p24 production, viral budding, and self-propagating ability of syncytia in HIV-infected SUP-T1 cell cultures and individually isolated syncytia seeded in uninfected SUP-T1 cell cultures. The results demonstrate that in these cultures syncytium formation is the principal mechanism of T cell death, syncytia are the main source of virus production, and both virus production and syncytium longevity are independent of syncytium size, but dependent on syncytium age, suggesting that both are programmed events.

Megakaryocytic progenitors can be generated ex vivo and safely administered to autologous peripheral blood progenitor cell transplant recipients

We evaluated different culture conditions to obtain a lineage-selected proliferation of clonogenic megakaryocytic progenitors (MP). In low-density (LD) or CD34+ cell cultures, the best results were obtained in serum-free medium in the presence of megakaryocyte growth and development factor, stem cell factor, interleukin-3 (IL-3), IL-6, IL-11, FLT-ligand, and macrophage inflammatory protein-1alpha. In paired studies, expansion of LD cells was less effective than expansion of CD34+ cells, and pre-enrichment of CD34+ cells using negative depletion of lineage-positive cells produced significantly larger quantities of MP than pre-enrichment using positive selection. MP proliferation peaked on day 7 in culture, and an 8- +/- 5-fold expansion of CD34+/CD61+ cells, a 17- +/- 5-fold expansion of colony-forming units-megakaryocytes, and a 58- +/- 14-fold expansion of the total number of CD61+ cells was obtained. In a feasibility clinical study, 10 cancer patients (8 with breast cancer and 2 with non-Hodgkin's lymphoma) undergoing autologous peripheral blood progenitor cell (PBPC) transplant received MP generated ex vivo (range, 1 to 21 x 10(5)/kg CD61 cells) together with unmanipulated PBPC. Eight patients received a single allogeneic platelet transfusion, whereas platelet transfusion support was not needed in 2 of the 4 patients receiving the highest doses of cultured MP. This result compares favorably with a retrospective control group of 14 patients, all requiring platelet transfusion support. Adverse reactions or bacterial contamination of cell cultures have not been observed. In conclusion, MP can be expanded ex vivo and safely administered to autologous transplant recipients. Further clinical trials will indicate the reinfusion schedule able to consistently abrogate the need for allogeneic platelet transfusion support in autologous transplantation.

Serum erythropoietin levels in children with leukemia

OBJECTIVE

Our aim was to test the hypothesis that, in leukemic children, serum erythropoietin (EPO) levels vary inversely with hemoglobin.

DESIGN

Twenty-four children (15 males, nine females) with an age range of 1-16 years (mean, 7.7 years) diagnosed with acute leukemia (22 acute lymphocytic, two acute myeloid) were studied over 4 months. Serum EPO and hemoglobin were measured simultaneously at multiple time points in the course of their disease, and a multiple regression analysis was performed to describe the EPO-hemoglobin relationship.

RESULTS

In a model adjusted for individual subject, there was a significant correlation between hemoglobin and logEPO in these leukemic children (r = -0.55, P < .01, n = 100). When measurements at hemoglobins less than 10.0 were analyzed the correlation increased significantly (r = -0.88, P < .01, n = 21). However, approximately 20% of the observations fell into one of two groups: an inappropriately low EPO for hemoglobin or an inappropriately elevated EPO for hemoglobin. The clinical characteristics of the children at each of these determinations were not different in any manner from the determinations which fell within the 95% confidence intervals for predicted mean EPO value: each of the outlying points came from a patient who at other times had an appropriate EPO for hemoglobin.

CONCLUSIONS

There existed a significant inverse relationship between hemoglobin and EPO, suggesting that the feedback mechanism for EPO is intact. Reasons for inappropriately high or low EPO, for level of hemoglobin, are not clear and may be reflective of other aspects of bone marrow or EPO metabolism.

Nitric oxide regulates nitric oxide synthase-2 gene expression by inhibiting NF-kappaB binding to DNA

Treatment of astroglial cells with interleukin 1beta and interferon gamma transcriptionally activates the nitric oxide synthase (NOS)-2 gene. The duration of mRNA expression is brief because of transcript instability. In addition, NO donors reduce the expression of NOS-2 mRNA dramatically by reducing the rate of transcription. In this study we observed that the NO donor, spermine NONOate did not inhibit the activation and translocation of NF-kappaB, a key transcription factor in the induction of NOS-2, but inhibited formation of the NF-kappaB-DNA complex. This effect was reversed by methaemoglobin (acting as an NO trap) and by the reducing agent dithiothreitol. Formation of the interferon-regulatory factor-DNA complex was unaffected by NO. These results suggest that NO can modulate its own production by interfering with NF-kappaB interaction with the promoter region of the NOS gene, a negative feedback effect that may be important for limiting NO production in vivo.

Management of immune thrombocytopenic purpura associated with the antiphospholipid antibody syndrome

Our two patients had "primary" antiphospholipid antibody syndrome without underlying systemic lupus erythematosus or other systemic autoimmune process, as well as symptomatic immune thrombocytopenic purpura (ITP). The thrombocytopenia did not respond to prolonged courses of corticosteroids and/or immune globulin infusions, but was controlled following splenectomy. The presence of serum antibodies to platelet surface glycoproteins, typical of ITP, could be helpful in the confirmation of both of these disorders in the same patient, rather than secondary thrombocytopenia. Management of such cases is confounded by an increased risk for both bleeding and thrombosis, including fetal death. To reduce the risk of fetal loss and thrombosis, both patients were advised to take aspirin 80 mg daily. The frequency and clinical significance of this association would suggest that patients with ITP should be tested for antiphospholipid antibodies, particularly before pregnancy or surgical procedures. Patients with coexistent antiphospholipid antibody syndrome would be at increased risk for thrombosis in the post-operative period following splenectomy and should be given prophylactic anticoagulation.

Health locus of control and value for health in smokers and nonsmokers

A representative sample of 11,401 persons completed a questionnaire, including measures of health locus of control, value for health, and smoking frequency. Smokers held stronger internal, chance, and powerful others beliefs than never smokers. Ex-smokers had lower scores on internal and chance dimensions and placed a higher value on their health than smokers. The interaction between chance health locus of control and value for health was a significant predictor of smoking status, suggesting that health value may moderate the relationship between health locus of control and smoking status. Within smokers, the health locus of control dimensions and value for health explained less than 1% of the variance in smoking frequency, with only the chance dimension emerging as a significant predictor.

Intracranial hypertension in Africans with cerebral malaria

The causes of death and neurological sequelae in African children with cerebral malaria are obscure. Intracranial pressure (ICP) was monitored and cerebral perfusion pressure (CPP) calculated in 23 Kenyan children with cerebral malaria. Four children had severe intracranial hypertension (ICP > 40 mm Hg, CPP < 40 mm Hg): two died, one with an ICP of 158 mm Hg and signs of transtentorial herniation, the other one with an ICP of 42 mm Hg and cardiorespiratory arrest. The other two survived with severe neurological sequelae. Nine had intermediate intracranial hypertension (ICP > 20 mm Hg, CPP < 50 mm Hg) and 10 had mild intracranial hypertension (maximum ICP 10-20 mm Hg); all survived without severe sequelae. Mannitol controlled the ICP in children with intermediate intracranial hypertension, but it did not prevent the development of intractable intracranial hypertension in children with severe intracranial hypertension. Intracranial hypertension is a feature of Kenyan children with cerebral malaria and severe intracranial hypertension is associated with a poor outcome.

Paramyotonia congenita and hyperkalemic periodic paralysis associated with a Met 1592 Val substitution in the skeletal muscle sodium channel alpha subunit--a large kindred with a novel phenotype

Paramyotonia congenita (PC) and Hyperkalemic periodic paralysis (HyperPP) are caused by amino acid substitutions in the alpha subunit of the human skeletal muscle sodium channel. One such substitution, methionine for valine at position 1592, has been associated with HyperPP with myotonia and cold sensitivity. We report clinical, electromyographic (EMG), genetic and pathological features of a large kindred with the Met1592Val substitution. Affected members were phenotypically heterogenous and had episodic potassium-sensitive paralysis, and stiffness and weakness induced by exercise and cold, which was confirmed by EMG studies. These features indicate a combined PC-HyperPP phenotype not previously described with this mutation.

Biology and treatment of acute lymphocytic leukemia in children

Biological factors and therapy interact in complex ways to affect prognosis of children with acute lymphocytic leukemia. Therefore, it is important that trials prospectively collect data on potential prognostic factors (such as age, white blood cell count, DNA index, cytogenetics, immunophenotype, central nervous system status, and early treatment response) in all patients. As results of treatment improve, subsequent trials must be large enough to detect small differences in outcomes. Results should be reported after sufficient follow-up, using multivariate analyses, and in a format that permits comparison with outcomes at other centers. Attention to the above will permit an approach to treatment that adapts the intensity of therapy to the risk of relapse.

Experience of the Polycythemia Vera Study Group with essential thrombocythemia: a final report on diagnostic criteria, survival, and leukemic transition by treatment

This report suggests modest changes in the criteria used for the diagnosis of ET and allows tentative recommendations concerning therapy. As outlined in Table I, we believe that absent stainable marrow iron does not necessarily indicate iron deficiency in these patients and that the serum ferritin and RBC mean corpuscular volume should be incorporated in this assessment. Normal values speak strongly against iron-deficient erythropoiesis. A search for the bcr/abl gene rearrangement should be included with the marrow karyotype to exclude CML. Finally, cytogenetic data and morphologic study of the marrow should be used to be certain that a MDS should not be considered. It may be that measurements of serum thrombopoietin levels may be useful in the future. Nonetheless, in principle, ET remains a diagnosis of exclusion as we have originally suggested. For therapy, HU remains an excellent choice for the older patient at risk for thrombosis. Nonetheless, no myelosuppressive therapy remains a perfectly viable option, particularly for the young patient and the older with low thrombotic risk. The roles of anagrelide and alpha interferon in this setting have not been fully defined. Experience with both has still been relatively short. It would be ideal if prospective, randomized trials could be mounted to address these questions. We conclude with confidence that return to older approaches such as 32P and AA in patients who fail on HU is to be discouraged. The use of anagrelide or interferon alfa seems to be a much more appropriate approach. We have not investigated the role of antithrombotic agents such as aspirin in ET. In PV, the combination of aspirin, 300 mg three times daily, and dipyridamole, 75 mg three times daily, failed to reduce the rate of thrombosis and was associated with an increased rate of hemorrhage. It is rational to suggest that lower doses of aspirin (ie, < 325 mg daily) might be associated with less hemorrhage and, perhaps, a beneficial effect on thrombosis. This remains to be shown.

Orthodromic activation of peptidergic cells in the medial amygdala

Electrical recordings from vasopressin-containing cells in the medial amygdala were obtained. Electrical stimulation of one major afferent structure, the accessory olfactory bulb, invariably elicited single unit discharge in the peptidergic cells and set up a field potential indicating widespread excitation in the structure. Pheromonal stimuli, normally borne into the brain by the accessory olfactory bulb, were ineffective in activating the medial amygdala. These results in combination with preexisting research suggest that the accessory olfactory bulb is an important influence, but not the only influence, on the activity of the peptidergic cells.

Puya: a method of attracting attention to relevant physical findings

Puya is a method that compares the physical exam in an electronic clinical note with a set of stereotypical physical exam sentences that have been previously classified as "normal". The note is then displayed in a web browser with normal findings clearly delineated. The list of stereotypical sentences comes from a set of physical findings found within extensive electronic medical record. This list is then screened to select only those that represent "normal" findings, a process that yields 96% total agreement among 4 clinicians surveyed. This final list of stereotypical "normal" sentences accounts for 64% of the clinical narrative text. Sentences in the clinical note that do not match sentences in the "normal" list are assumed to be "abnormal". Puya screened 98 clinical notes consisting of 610 individual sentences. Puya achieved a sensitivity of 100%, a specificity of 63%, a positive predictive value of 44% and a negative predictive value of 100%. This leads to an application that reduces informational noise.

Comparison of the HOTV and Lea Symbols charts for preschool vision screening

PURPOSE

Two preliterate acuity charts, the Lea Symbol chart and the HOTV chart, were compared prospectively in an established preschool vision screening program. The charts were compared by measuring time required to test, reliability coefficients, and the percentage of children testable with each chart.

METHODS AND MATERIALS

Seven hundred and seventy-seven 3- to 5-year-old children were randomized to four screening sequences that determined the order of chart use. Each child was screened on two occasions within 6 weeks. Testing was performed at 10 feet, and optotypes were not isolated for testing.

RESULTS

Mean test time was significantly less for older children, but was not related to the chart used. Reliability coefficients were similar for the Lea Symbols and the HOTV charts. The percentage of children testable by each chart improved with increased age of the child. More 3 year olds were testable with the Lea Symbols chart compared to the HOTV chart (92% versus 85%, P = .05).

CONCLUSIONS

Vision screening with either chart was more rapid and more frequently achieved with 4- and 5-year-old children compared with the 3 year olds. For the population as a whole, each chart gave similar results. Among the 3 year olds, however, testability rates were better for the Lea Symbols chart. The Lea Symbols chart is an acceptable option for preschool vision screening, and may be more efficacious than the HOTV chart for screening 3-year-old children.

General practitioners' immediate management of men presenting with urethral symptoms

OBJECTIVES

To describe the immediate reported management, by general practitioners (GPs), of men presenting with symptoms of urethral discharge, or dysuria only.

SUBJECTS

All 692 GPs in practice in Brent, Harrow, Ealing, Hammersmith, and Hounslow (UK).

METHOD

Data were collected using a GP completed questionnaire concerning the management of the last male patient seen, aged less than 40 years, complaining of urethral discharge, and the last male patient under 40 years complaining of dysuria only.

RESULTS

The response rate among GPs was 52%. Fifty three per cent of men with urethral symptoms, 86% of men with a urethral discharge and 24% with dysuria only, were identified by GPs and referred without investigation or treatment to a genitourinary medicine clinic. Of men with dysuria only, 93% of investigations by GPs were reported to include a mid-stream urine (MSU) specimen for bacteriology, and 19% a urethral swab for chlamydia. Seventy eight per cent of GPs reported using treatments with a broad spectrum antibiotic, 53% with trimethoprim, whilst 14% of GPs reported using a tetracycline in common use to treat non-gonococcal urethritis. Urine specimens were reported to be "culture positive" in 41% of men who had an MSU specimen tested, and 15% of men who had a urethral swab tested were reported to be chlamydia positive.

CONCLUSION

The GPs included in this study were not a full sample, or representative of all the GPs, and the data are retrospective. Nevertheless, we found a large difference in GPs reported management for men with urethral symptoms according to whether or not urethral discharge was a reported complaint. Reported management is likely to be, at least, indicative of actual management. Therefore, the results suggest that assessment by GPs of men presenting with dysuria should be explored and more appropriate management strategies defined.

An investigation into the physical stability of a neonatal parenteral nutrition formulation

The physical stability of a neonatal parenteral nutrition formulation has been examined using differential interference contrast (DIC) microscopy. In vitro studies indicated that particle size increases occur immediately after mixing the Intralipid emulsion with the amino acid/glucose solution, while simulation of clinical administration indicated that larger droplets were observed at the end of the catheter approximately 1 h after administration commenced. Microscopic observation of adjacent droplets of the two fluids showed reversible aggregation occurring almost immediately. It was concluded that the current method of administering this neonatal emulsion does not prevent droplet coalescence.

Haemagglutination properties of Moraxella (Branhamella) catarrhalis

The ability of 30 isolates of Moraxella (Branhamella) catarrhalis to haemagglutinate erythrocytes of five species was examined. Two haemagglutination phenotypes of M. catarrhalis were observed: phenotype I isolates (n = 10) agglutinated human erythrocytes, while phenotype II isolates (n = 7) agglutinated both human and rabbit erythrocytes. No haemagglutination was observed with chick, sheep or horse erythrocytes. Haemagglutination by both phenotype I and II isolates was abolished following treatment of these isolates with pronase and trypsin, while heat treatment at 70 degrees C markedly reduced the level of haemagglutination by both sets of isolates. Haemagglutination by phenotype II isolates was inhibited by galactose, whereas haemagglutination by phenotype I isolates was not inhibited by this carbohydrate. Transmission electron microscopy (TEM) studies showed that very close cell-surface interactions occurred when both phenotypes of M. catarrhalis adhered to the human erythrocyte. Fimbrial attachment was not apparent. Haemagglutinating isolates of both phenotypes had a trypsin-sensitive outer fibrillar coat when examined by TEM.

Deep breathing in children with severe malaria: indicator of metabolic acidosis and poor outcome

Despite the frequent association of respiratory symptoms and signs with malarial morbidity and mortality in sub-Saharan Africa, the value of individual symptoms and signs has rarely been assessed. We have prospectively examined the association of individual clinical findings with the summary diagnosis of respiratory distress, outcome, and the presence of metabolic acidosis in children admitted with severe malaria to a Kenyan district hospital. Respiratory distress was present in 119 of the 350 children included in the study and in 23 of the 30 deaths (relative risk = 6.5, 95% confidence interval = 2.8-14.4). The features of a history of dyspnea, nasal flaring, and indrawing or deep breathing (Kussmaul's respiration) were individually most closely associated with the summary diagnosis of respiratory distress. Of these, deep breathing, which was sensitive (91%) and specific (83%) for the presence of severe metabolic acidosis (base excess < or = -12), is the best candidate sign to represent the prognostically important syndrome of malarial respiratory distress. Therefore, it warrants further prospective evaluation in different clinical settings and areas of different malaria endemicity.