Zinc Lowers Amyloid-β Toxicity by Selectively Precipitating Aggregation Intermediates

Soluble amyloid-beta (Abeta) aggregates are suspected to play a major role in Alzheimer's disease. Zn2+ at a concentration of a few micromolar, which is too dilute to affect the precipitation equilibrium of Abeta, can destabilize these aggregates [Garai, K., Sengupta, P., Sahoo, B., and Maiti, S. (2006) Biochem. Biophys. Res. Commun. 345, 210-215]. Here we investigate the nature of these aggregates in the context of the precipitation pathway, the mechanism underlying their destabilization, and the biological consequences of this destabilization. We show that the larger soluble aggregates (size >10 nm) form only in supersaturated Abeta solutions, implying that they are intermediates in the pathway toward fibril formation. We also show that Zn2+ destabilizes these intermediates by accelerating their aggregation kinetics. The resulting change in the size distribution of the Abeta solution is sufficient to eliminate its toxicity to cultured mammalian neurons. Our results provide an explanation for the existing observations that Zn2+ at a concentration of a few micromolar significantly reduces Abeta toxicity.

Quantitative measurement of serotonin synthesis and sequestration in individual live neuronal cells

Synthesis and subsequent sequestration into vesicles are essential steps that precede neurotransmitter exocytosis, but neither the total neurotransmitter content nor the fraction sequestered into vesicles have been measured in individual live neurons. We use multiphoton microscopy to directly observe intracellular and intravesicular serotonin in the serotonergic neuronal cell line RN46A. We focus on how the relationship between synthesis and sequestration changes as synthesis is up-regulated by differentiation or down-regulated by chemical inhibition. Temperature-induced differentiation causes an increase of about 60% in the total serotonin content of individual cells, which goes up to about 10 fmol. However, the number of vesicles per cell increases by a factor of four and the proportion of serotonin sequestered inside the vesicles increases by a factor of five. When serotonin synthesis is inhibited in differentiated cells and the serotonin content goes down to the level present in undifferentiated cells, the sequestered proportion still remains at this high level. The total neurotransmitter content of a cell is, thus, an unreliable indicator of the sequestered amount.

Some neurophysiological constraints on models of word naming

The pronunciation of irregular words in deep orthographies like English cannot be specified by simple rules. On the other hand, the fact that novel letter strings can be pronounced seems to imply the existence of such rules. These facts motivate dual-route models of word naming, which postulate separate lexical (whole-word) and non-lexical (rule-based) mechanisms for accessing phonology. We used fMRI during oral naming of irregular words, regular words, and nonwords, to test this theory against a competing single-mechanism account known as the triangle model, which proposes that all words are handled by a single system containing distributed orthographic, phonological, and semantic codes rather than word codes. Two versions of the dual-route model were distinguished: an 'exclusive' version in which activation of one processing route predominates over the other, and a 'parallel' version in which both routes are equally activated by all words. The fMRI results provide no support for the exclusive dual-route model. Several frontal, insular, anterior cingulate, and parietal regions showed responses that increased with naming difficulty (nonword > irregular word > regular word) and were correlated with response time, but there was no activation consistent with the predicted response of a non-lexical, rule-based mechanism (i.e., nonword > regular word > irregular word). Several regions, including the angular gyrus and dorsal prefrontal cortex bilaterally, left ventromedial temporal lobe, and posterior cingulate gyrus, were activated more by words than nonwords, but these 'lexical route' regions were equally active for irregular and regular words. The results are compatible with both the parallel dual-route model and the triangle model. 'Lexical route' regions also showed effects of word imageability. Together with previous imaging studies using semantic task contrasts, the imageability effects are consistent with semantic processing in these brain regions, suggesting that word naming is partly semantically-mediated.

Spontaneous coronary artery dissection in the postpartum period: association with antiphospholipid antibody

Spontaneous coronary artery dissection (SCAD) is an extremely uncommon cause of myocardial infarction, occurring predominantly in women during or after pregnancy. The exact aetiology is unknown. This report describes a 33 year postpartum woman with diagnosed SCAD who tested positive for anticardiolipin antibody. This is the first case of SCAD in a patient with antiphospholipid antibody. The authors hypothesised that there should be a strong association between them.

Eosinophilic granuloma with oral manifestations: a case report

Eosinophilic granuloma is the most benign disorder of the triad commonly known as histocytosis X. In this article a case of a 6 year old female child with multiple eosinophilic granuloma with additional liver dysfunction and its oral manifestation is presented. This case demonstrated that oral findings, may be an early manifestation of the disease, definitive diagnosis needs to be determined by correlation of the clinical findings with histologic features. For the duration of 8 years the case has been followed up, there has been a progressive healing of the lesion, the clinical manifestations of the disease resolved with only chemotherapy and provided a very good prognosis.

Live cell ultraviolet microscopy: A comparison between two- and three-photon excitation

We compare conventional infrared laser based three-photon excitation with a visible laser based two-photon excitation scheme for imaging the ultraviolet fluorophore serotonin in solution and in live cells. To obtain a signal level of 1000 photons per second per mM serotonin solution, we need a back aperture power of 5 mW at 550 nm (for two-photon excitation) and 33 mW at 740 nm (for three-photon excitation). The detectivity of serotonin (defined as the concentration of serotonin that yields a signal equivalent to three times the standard deviation of the signal obtained from the buffer alone) is 12 microM for two-photon, and 220 microM for three-photon excitation. Surprisingly, for live cell imaging of vesicular serotonin in serotonergic cells, three-photon excitation appears to provide better image contrast than two-photon excitation. The origin of this is traced to the concentration-dependent shift of the serotonin emission spectrum.

Partial and generalized epilepsy with febrile seizures plus and a novel SCN1A mutation

BACKGROUND

Generalized epilepsy with febrile seizures plus (GEFS+) is an autosomal dominant syndrome characterized by febrile seizures (FS) and a variety of afebrile generalized seizure types. GEFS+ has previously been linked to mutations in two genes encoding the voltage-gated sodium channel alpha-subunit (SCN1A) and beta1-subunit (SCN1B). We studied a large family with FS and partial as well as generalized seizure types.

METHODS

All but two living affected family members were interviewed and examined. Information on deceased affected family members was sought. EEG for 11 affected family members and one unaffected family member were obtained. Genetic linkage analysis and mutation screening of SCN1A were performed on blood samples from 16 affected individuals and their first-degree relatives.

RESULTS

There were 27 affected family members; 18 were alive at the time of the study. All affected family members had FS; seven had FS only, and 19 also had afebrile seizures. Eleven individuals continued to have FS beyond 6 years of age. FS were complex in 12 family members, usually with prolonged duration. The index patient had right temporal lobe epilepsy and hippocampal sclerosis. Four other patients had strong historical evidence of temporal lobe epilepsy, and three others had nonlocalizing evidence of partial epilepsy. Pedigree analysis indicated autosomal dominant transmission. All affected individuals who were tested and one asymptomatic individual had a sodium channel mutation of SCN1A, an A-->C transversion at nucleotide 3809 resulting in the substitution of lysine 1270 by threonine in the D3/S2 segment (designated as K1270T).

CONCLUSIONS

Our findings indicate that partial epilepsy preceded by FS can be associated with sodium channel mutations and may represent a variant of GEFS+.

Impact of clozapine prescription on inpatient resource utilization

Although clozapine has been demonstrated to be clinically superior to typical neuroleptics in refractory schizophrenia, it is also more expensive. It had been hoped that the increased costs associated with its use would be offset by decreases in the utilization of other expensive resources, especially inpatient care. All patients who had clozapine initiated during an inpatient hospitalization within the VA for schizophrenia over a 4-year period (N = 1415) were matched with a comparison group (N = 2,830) on key service utilization variables and other possible confounding demographic and clinical variables using propensity scoring-an accepted statistical method, although still relatively little used in psychiatry. By using centralized VA databases, subsequent inpatient resource utilization for the 3 years after index discharge was examined. Veterans exposed to clozapine while inpatients recorded 33 (36%) more inpatient days in the subsequent 3 years after discharge than the comparison group (124 +/- 190 days vs. 91 +/- 181 days, p = .0002). When all patients exposed to clozapine were divided according to whether they had received 1 year of clozapine treatment after discharge, those that received less than 1 year's treatment recorded significantly more inpatient days than either those maintained on clozapine or controls. These results suggest that in actual practice clozapine treatment may cost substantially more than treatment with conventional neuroleptics.

Perceived needs and service use of Spanish speaking monolingual patients followed at a Hispanic clinic

This study compared Spanish speaking monolingual patients at a Hispanic Clinic, with Hispanics and non-Hispanics at a conventional mental health center. A questionnaire in English and Spanish surveyed sociodemographic characteristics and subjectively reported health needs. The monolingual Hispanic Clinic patients perceived a significantly greater need for help with health and benefits, and better access to physical health care providers. Hispanics seen at the Hispanic Clinic report more difficulties managing medications than the other groups suggesting that this problem is not adequately addressed by receiving services in a culturally sensitive clinic, possibly due to the persistent effect of language barriers and low level of education. Additional interventions may be needed to address this problem.

Impact of clozapine on completed suicide

OBJECTIVE

Clozapine has been found to be superior to typical neuroleptics in ameliorating the symptoms of refractory schizophrenia. This study evaluated clozapine's effect on the rate of death due to suicide.

METHOD

All patients over a 4-year period who initiated treatment with clozapine while hospitalized within the Department of Veterans Affairs (VA) system (N=1,415) were matched with a schizophrenic control group (N=2,830) by propensity scoring-a widely accepted statistical method that has been used relatively little in psychiatric research. Centralized VA databases and a national death registry were used to identify all deaths within the two groups, along with listed causes, for the 3 years after discharge.

RESULTS

Veterans exposed to clozapine while inpatients were significantly less likely to die during the follow-up period than those in the control group, but this was entirely attributable to the much lower rate of death due to respiratory disorders in the clozapine group. There were no significant differences in rates of suicide or accidental death.

CONCLUSIONS

These results fail to support the hypothesis that clozapine treatment is associated with significantly fewer deaths due to suicide.

synaptotagmin mutants reveal essential functions for the C2B domain in Ca2+-triggered fusion and recycling of synaptic vesicles in vivo

Synaptotagmin has been proposed to function as a Ca(2+) sensor that regulates synaptic vesicle exocytosis, whereas the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex is thought to form the core of a conserved membrane fusion machine. Little is known concerning the functional relationships between synaptotagmin and SNAREs. Here we report that synaptotagmin can facilitate SNARE complex formation in vitro and that synaptotagmin mutations disrupt SNARE complex formation in vivo. Synaptotagmin oligomers efficiently bind SNARE complexes, whereas Ca(2+) acting via synaptotagmin triggers cross-linking of SNARE complexes into dimers. Mutations in Drosophila that delete the C2B domain of synaptotagmin disrupt clathrin AP-2 binding and endocytosis. In contrast, a mutation that blocks Ca(2+)-triggered conformational changes in C2B and diminishes Ca(2+)-triggered synaptotagmin oligomerization results in a postdocking defect in neurotransmitter release and a decrease in SNARE assembly in vivo. These data suggest that Ca(2+)-driven oligomerization via the C2B domain of synaptotagmin may trigger synaptic vesicle fusion via the assembly and clustering of SNARE complexes.

Consumer experience with payeeship provided by a community mental health center

We surveyed 28 participants in a program in which the clinical therapist and money manager were different staff members. Patients reported strong therapeutic alliances with both the money manager and treating therapist as assessed by the Working Alliance Inventory. Alliance scores for the two providers were highly correlated (p = .68) and not significantly different from each other. Most patients endorsed overall satisfaction with the money management service, and report program-related benefits in housing, achieving abstinence, avoiding financial predators and budgeting arrangements. A significant minority endorsed some feeling of coercion, and coercion was associated with a weaker therapeutic alliance.

Ca2+-activated K+ channels in human leukemic Jurkat T cells. Molecular cloning, biochemical and functional characterization

Previous studies have demonstrated the presence of apamin-sensitive, small-conductance Ca(2+)-activated K(+) currents in human leukemic Jurkat T cells. Using a combined cDNA and reverse transcriptase-polymerase chain reaction cloning strategy, we have isolated from Jurkat T cells a 2.5-kilobase cDNA, hSK2, encoding the human isoform of SK2 channels. Northern blot analysis reveals the presence of a 2.5-kilobase hSK2 transcript in Jurkat T cells. While present in various human tissues, including brain, heart, skeletal muscle, kidney, and liver, no hSK2 mRNA could be detected in resting and activated normal human T cells. The hSK2 gene is encoded by 8 exons and could be assigned to chromosome 5 (q21.2-q22.1). The protein encoded by hSK2 is 579 amino acids long and exhibits 97% identity with its rat counterpart rSK2. When expressed in Chinese hamster ovary cells, hSK2 produces Ca(2+)-activated K(+) currents with a unitary conductance of 9.5 pS and a K(0.5) for calcium of 0.7 microm; hSK2 currents are inhibited by apamin, scyllatoxin, and d-tubocurarine. Overexpression of the Src family tyrosine kinase p56(lck) in Jurkat cells, up-regulates SK2 currents by 3-fold. While IKCa channels are transcriptionally induced upon activation of normal human T cells, our results show that in Jurkat cells SK2 channels are constitutively expressed and down-regulated following mitogenic stimulation.

Skeletal benefits of alendronate: 7-year treatment of postmenopausal osteoporotic women. Phase III Osteoporosis Treatment Study Group

We report here the second 2-yr extension of a clinical trial among postmenopausal women; 235 women continued blinded treatment with 5 or 10 mg alendronate daily, and 115 women who had been treated with alendronate for 5 yr were switched to blinded placebo. Continuous treatment with alendronate (10 mg daily) for 7 yr increased lumbar spine bone mineral density (BMD) by 11.4% compared to baseline. After the initial 18 months, each additional year of treatment through yr 7 increased spine BMD by 0.8% for the 10-mg dose and 0.6% for the 5-mg dose, with significant increases during yr 6-7. Previously reported increases in BMD at other skeletal sites and decreases in biochemical markers of bone turnover remained stable during yr 6-7. Among women previously taking alendronate for 5 yr who were switched to placebo, there was no significant decline in BMD at the spine or hip, whereas small, but significant, decreases in BMD at the forearm and total body and small increases in biochemical markers were observed. The safety and tolerability profiles were similar to those of placebo. This is the largest published long-term study of antiresorptive therapy. Our findings indicate that long-term alendronate treatment is well tolerated and effective for 7 yr. Increases in spinal BMD continue for at least 7 yr, and other skeletal benefits are maintained. Discontinuation does not lead to accelerated bone loss, but continuous treatment yields better skeletal benefits than shorter treatment.

Lobular capillary hemangiomas: An epidemiologic report, with emphasis on cutaneous lesions

BACKGROUND

Lobular capillary hemangiomas (pyogenic granulomas) occur on both mucosal and cutaneous surfaces. There are conflicting data regarding the increased prevalence of lobular capillary hemangiomas in female versus male subjects. Some studies have noted a female predominance of lobular capillary hemangiomas, but other studies do not reveal such a disparity. Because of an increased prevalence during pregnancy, oral tumors are also known as "granuloma gravidarum" or "pregnancy tumors." A hormonal influence for these mucosal lesions has been postulated. There are, however, no studies that address a possible relationship between hormones and cutaneous lesions.

OBJECTIVE

This study presents the epidemiology of lobular capillary hemangiomas, with an emphasis on cutaneous lesions.

METHODS

We reviewed 63,759 dermatopathology reports from a regional, private dermatopathology laboratory and found 325 cases of lobular capillary hemangiomas over a 1-year period.

RESULTS

In our study of lobular capillary hemangiomas, cutaneous lesions accounted for 86%, with mucosal lesions representing only 12% of cases. Seven cases were excluded (one was intravascular, two were subcutaneous, and in 4 the location was not specified). Overall, male patients outnumbered female patients. The peak incidence for cutaneous lobular capillary hemangiomas was found in the second decade of life. The most common cutaneous sites were the trunk, upper extremities, and head. Mucosal lesions were primarily seen on the lips, gingiva, and tongue, and these affected females more than males by a ratio of 2:1, most commonly in the fourth decade of life.

CONCLUSION

Cutaneous lobular capillary hemangiomas were equally prevalent in male and female patients. This would refute a female hormonal influence in the induction of cutaneous lobular capillary hemangiomas. Our data may suggest a hormonal influence on mucosal lesions because mucosal lobular capillary hemangiomas were twice as common in female patients. However, the small number of lesions in our study precludes us from making such a conclusion.

Extracellular K(+) and opening of voltage-gated potassium channels activate T cell integrin function: physical and functional association between Kv1.3 channels and beta1 integrins

Elevated extracellular K(+) ([K(+)](o)), in the absence of "classical" immunological stimulatory signals, was found to itself be a sufficient stimulus to activate T cell beta1 integrin moieties, and to induce integrin-mediated adhesion and migration. Gating of T cell voltage-gated K(+) channels (Kv1.3) appears to be the crucial "decision-making" step, through which various physiological factors, including elevated [K(+)](o) levels, affect the T cell beta1 integrin function: opening of the channel leads to function, whereas its blockage prevents it. In support of this notion, we found that the proadhesive effects of the chemokine macrophage-inflammatory protein 1beta, the neuropeptide calcitonin gene-related peptide (CGRP), as well as elevated [K(+)](o) levels, are blocked by specific Kv1.3 channel blockers, and that the unique physiological ability of substance P to inhibit T cell adhesion correlates with Kv1.3 inhibition. Interestingly, the Kv1.3 channels and the beta1 integrins coimmunoprecipitate, suggesting that their physical association underlies their functional cooperation on the T cell surface. This study shows that T cells can be activated and driven to integrin function by a pathway that does not involve any of its specific receptors (i.e., by elevated [K(+)](o)). In addition, our results suggest that undesired T cell integrin function in a series of pathological conditions can be arrested by molecules that block the Kv1.3 channels.

Benchmarking treatment of schizophrenia: a comparison of service delivery by the national government and by state and local providers

This study compared treatment of schizophrenia in two types of organization: a national, government-operated health care system, the Department of Veterans Affairs (VA), and in hospitals and clinics operated by state and local providers. Between 1994 and 1996, 746 male patients with a clinical diagnosis of schizophrenia residing in two states in the Southeast and Midwest were surveyed: 192 VA inpatients were compared with 96 non-VA inpatients, and 274 VA outpatients were compared with 184 non-VA outpatients. VA patients were older and had higher incomes than non-VA patients but did not differ significantly on measures of clinical status, satisfaction with providers, or community adjustment. VA outpatients were more likely to have been hospitalized during the previous year than non-VA outpatients and were less likely to have received services from a day hospital, from a case manager or social worker, or to have received crisis intervention services. On 5 of 26 Schizophrenic Patient Outcomes Research Team treatment recommendations, a smaller proportion of VA than non-VA patients adhered to standards. Four of these reflected reduced access among VA patients to psychosocial services such as work therapy, job training, or case management services. Cross-sectional surveys can be used to compare quality of care across service systems. VA care was associated with similar satisfaction and clinical outcomes but greater reliance on hospital treatment and less use of community-based psychosocial services.

The potential of in situ hybridization and an immunogold assay to identify Legionella associations with other microorganisms

Based on in vitro studies, bacteria in the genus Legionella are believed to multiply within protozoa such as amoebae in aquatic environments. Current methods used for detection of Legionella species, however, are not designed to show this relationship. Thus the natural intimate association of Legionella with other microorganisms remains to be clearly documented and the extent to which protozoa might be infected with Legionella species remains undefined. In this report we describe methods based on the use of Legionella specific reagents that would prove useful in describing its associations with other microorganisms. An immunogold and in situ hybridization technique have the potential to demonstrate the natural occurrence of Legionella species in free-living amoebae. In preliminary observations, however, bacteria reactive with Legionella specific reagents were often not intimately associated with amoebae. Bacteria occurred as free single cells, as cell aggregates, in proximity to other cells and debris, and only occasionally in close proximity to amoebae. Although some Legionella species replicate within amoebae, these preliminary observations suggest the bacteria may be encountered most frequently as extracellular microorganisms, either free-floating or in association with other structures or microorganisms. The future use of these techniques will aid in the elucidation of any naturally occurring relationships between Legionella species and other microorganisms.

Preventing hypothermia: convective and intravenous fluid warming versus convective warming alone

STUDY OBJECTIVE

To test the hypothesis that warming intravenous (i.v.) fluids in conjunction with convective warming results in less intraoperative hypothermia (core temperature < 36.0 degrees C) than that seen with convective warming alone.

DESIGN

Prospective, randomized study.

SETTING

University affiliated tertiary care teaching hospital.

PATIENTS

61 ASA physical status, I, II, and III adults undergoing major surgery and general anesthesia with isoflurane.

INTERVENTIONS

All patients received convective warming. Group 1 patients received warmed fluids (setpoint 42 degrees C). Group 2 patients received room temperature fluids (approximately 21 degrees C).

MEASUREMENTS AND MAIN RESULTS

Lowest and final intraoperative distal esophageal temperatures were higher (p < 0.05) in Group 1 (mean +/- SEM: 35.8 +/- 0.1 degrees C and 36.6 +/- 0.1 degrees C) versus Group 2 (35.4 +/- 0.1 degrees C and 36.1 +/- 0.1 degrees C, respectively). Compared with Group 1, more Group 2 patients were hypothermic at the end of anesthesia (10 of 26 patients, or 38.5% vs. 4 of 30 patients, or 13%; p < 0.05). After 30 minutes in the recovery room, there were no differences in temperature between groups (36.7 +/- 0.1 degrees C and 36.5 +/- 0.1 degrees C in Groups 1 and 2, respectively). Intraoperative cessation of convective warming because of core temperature greater than 37 degrees C was required in 33% of Group 1 patients (vs. 11.5% in Group 2; p = 0.052).

CONCLUSIONS

The combination of convective and fluid warming was associated with a decreased likelihood of patients leaving the operating room hypothermic. However, average final temperatures were greater than 36 degrees C in both groups, and intergroup differences were small. Care must be taken to avoid overheating the patient when both warming modalities are employed together.

"Facilitated" amino acid transport is upregulated in brain tumors

The goal of this study was to determine the magnitude of "facilitated" amino acid transport across tumor and brain capillaries and to evaluate whether amino acid transporter expression is "upregulated" in tumor vessels compared to capillaries in contralateral brain tissue. Aminocyclopentane carboxylic acid (ACPC), a non-metabolized [14C]-labeled amino acid, and a reference molecule for passive vascular permeability, [67Ga]-gallium-diethylenetriaminepentaacetic acid (Ga-DTPA), were used in these studies. Two experimental rat gliomas were studied (C6 and RG2). Brain tissue was rapidly processed for double label quantitative autoradiography 10 minutes after intravenous injection of ACPC and Ga-DTPA. Parametric images of blood-to-brain transport (K1ACPC and K1Ga-DTPA, microL/min/g) produced from the autoradiograms and the histology were obtained from the same tissue section. These three images were registered in an image array processor; regions of interest in tumor and contralateral brain were defined on morphologic criteria (histology) and were transferred to the autoradiographic images to obtain mean values. The facilitated component of ACPC transport (deltaK1ACPC) was calculated from the K1ACPC and K1Ga-DTPA data, and paired comparisons between tumor and contralateral brain were performed. ACPC flux, K1ACPC, across normal brain capillaries (22.6 +/- 8.1 microL/g/min) was >200-fold greater than that of Ga-DTPA (0.09 +/- 0.04 microL/g/min), and this difference was largely (approximately 90%) due to facilitated ACPC transport. Substantially higher K1ACPC values compared to corresponding K1DTPA values were also measured in C6 and RG2 gliomas. The deltaK1ACPC values for C6 glioma were more than twice that of contralateral brain cortex. K1ACPC and deltaK1ACPC values for RG2 gliomas was not significantly higher than that of contralateral cortex, although a approximately 2-fold difference in facilitated transport is obtained after normalization for differences in capillary surface area between RG2 tumors and contralateral cortex. K1ACPC, deltaK1ACPC, and K DTPA were directly related to tumor cell density, were higher in regions of "impending" necrosis, and the tumor/contralateral brain ACPC radio-activity ratios (0 to 10 minutes) were very similar to that obtained with 0 to 60 minutes experiments. These results indicate that facilitated transport of ACPC is upregulated across C6 and RG2 glioma capillaries, and that tumors can induce upregulation of amino acid transporter expression in their supporting vasculature. They also suggest that early imaging (e.g., 0 to 20 minutes) with radiolabeled amino acids in a clinical setting may be optimal for defining brain tumors.