Contractility defects hinder glycoprotein VI-mediated platelet activation and affect platelet functions beyond clot contraction.

Background: Active and passive biomechanical properties of platelets contribute substantially to thrombus formation. Actomyosin contractility drives clot contraction required for stabilizing the hemostatic plug. Impaired contractility results in bleeding but is difficult to detect using platelet function tests. Objectives: To determine how diminished myosin activity affects platelet functions, including and beyond clot contraction. Methods: Using the myosin IIA-specific pharmacologic inhibitor blebbistatin, we modulated myosin activity in platelets from healthy donors and systematically characterized platelet responses at various levels of inhibition by interrogating distinct platelet functions at each stage of thrombus formation using a range of complementary assays. Results: Partial myosin IIA inhibition neither affected platelet von Willebrand factor interactions under arterial shear nor platelet spreading and cytoskeletal rearrangements on fibrinogen. However, it impacted stress fiber formation and the nanoarchitecture of cell-matrix adhesions, drastically reducing and limiting traction forces. Higher blebbistatin concentrations impaired platelet adhesion under flow, altered mechanosensing at lamellipodia edges, and eliminated traction forces without affecting platelet spreading, α-granule secretion, or procoagulant platelet formation. Unexpectedly, myosin IIA inhibition reduced calcium influx, dense granule secretion, and platelet aggregation downstream of glycoprotein (GP)VI and limited the redistribution of GPVI on the cell membrane, whereas aggregation induced by adenosine diphosphate or arachidonic acid was unaffected. Conclusion: Our findings highlight the importance of both active contractile and passive crosslinking roles of myosin IIA in the platelet cytoskeleton. They support the hypothesis that highly contractile platelets are needed for hemostasis and further suggest a supportive role for myosin IIA in GPVI signaling.

Deep brain stimulation of thalamus for epilepsy.

Neuromodulation (neurostimulation) is a relatively new and rapidly growing treatment for refractory epilepsy. Three varieties are approved in the US: vagus nerve stimulation (VNS), deep brain stimulation (DBS) and responsive neurostimulation (RNS). This article reviews thalamic DBS for epilepsy. Among many thalamic sub-nuclei, DBS for epilepsy has been targeted to the anterior nucleus (ANT), centromedian nucleus (CM), dorsomedial nucleus (DM) and pulvinar (PULV). Only ANT is FDA-approved, based upon a controlled clinical trial. Bilateral stimulation of ANT reduced seizures by 40.5% at three months in the controlled phase (p = .038) and 75% by 5 years in the uncontrolled phase. Side effects related to paresthesias, acute hemorrhage, infection, occasional increased seizures, and usually transient effects on mood and memory. Efficacy was best documented for focal onset seizures in temporal or frontal lobe. CM stimulation may be useful for generalized or multifocal seizures and PULV for posterior limbic seizures. Mechanisms of DBS for epilepsy are largely unknown, but animal work points to changes in receptors, channels, neurotransmitters, synapses, network connectivity and neurogenesis. Personalization of therapies, in terms of connectivity of the seizure onset zone to the thalamic sub- nucleus and individual characteristics of the seizures, might lead to improved efficacy. Many questions remain about DBS, including the best candidates for different types of neuromodulation, the best targets, the best stimulation parameters, how to minimize side effects and how to deliver current noninvasively. Despite the questions, neuromodulation provides useful new opportunities to treat people with refractory seizures not responding to medicines and not amenable to resective surgery.

Complex negative emotions induced by electrical stimulation of the human hypothalamus.

BACKGROUND: Stimulation of the ventromedial hypothalamic region in animals has been reported to cause attack behavior labeled as sham-rage without offering information about the internal affective state of the animal being stimulated. OBJECTIVE: To examine the causal effect of electrical stimulation near the ventromedial region of the human hypothalamus on the human subjective experience and map the electrophysiological connectivity of the hypothalamus with other brain regions. METHODS: We examined a patient (Subject S20_150) with intracranial electrodes implanted across 170 brain regions, including the hypothalamus. We combined direct electrical stimulation with tractography, cortico-cortical evoked potentials (CCEP), and functional connectivity using resting state intracranial electroencephalography (EEG). RESULTS: Recordings in the hypothalamus did not reveal any epileptic abnormalities. Electrical stimulations near the ventromedial hypothalamus induced profound shame, sadness, and fear but not rage or anger. When repeated single-pulse stimulations were delivered to the hypothalamus, significant responses were evoked in the amygdala, hippocampus, ventromedial-prefrontal and orbitofrontal cortices, anterior cingulate, as well as ventral-anterior and dorsal-posterior insula. The time to first peak of these evoked responses varied and earliest propagations correlated best with the measures of resting-state EEG connectivity and structural connectivity. CONCLUSION: This patient's case offers details about the affective state induced by the stimulation of the human hypothalamus and provides causal evidence relevant to current theories of emotion. The complexity of affective state induced by the stimulation of the hypothalamus and the profile of hypothalamic electrophysiological connectivity suggest that the hypothalamus and its connected structures ought to be seen as causally important for human affective experience.

The SANTÉ study at 10 years of follow-up: Effectiveness, safety, and sudden unexpected death in epilepsy.

OBJECTIVE: We evaluated the efficacy and safety of deep brain anterior thalamus stimulation after 7 and 10 years, and report the incidence of sudden unexpected death in epilepsy (SUDEP) and overall mortality in adults in the Stimulation of the Anterior Nucleus of the Thalamus for Epilepsy (SANTÉ) study. METHODS: After the 3-month blinded and 9-month unblinded phases, subjects continued to be assessed during long-term follow-up (LTFU) and later a continued therapy access phase (CAP), to further characterize adverse events and the incidence of SUDEP. Stimulus parameter and medication changes were allowed. RESULTS: One hundred ten implanted subjects accumulated a total of 938 device-years of experience (69 subjects during the LTFU phase and 61 subjects in the CAP phase). Prior to study closure, 57 active subjects continued therapy at 14 study centers, with follow-up of at least 10 (maximum 14) years. At 7 years, median seizure frequency percent reduction from baseline was 75% (p < .001), with no outcome differences related to prior vagus nerve stimulation or resective surgery. The most severe seizure type, focal to bilateral tonic-clonic, was reduced by 71%. Adding new antiseizure medications did not impact the pattern of seizure reduction over time. There were no unanticipated serious adverse events in the study. The definite-plus-probable SUDEP rate, based on SANTÉ study experience (two deaths in 938 years) and previous pilot studies (0 deaths in 76 years), indicated a rate of 2.0 deaths for 1000 person-years. Overall mortality was 6.9 deaths per 1000 person-years. SIGNIFICANCE: The long-term efficacy and safety profiles of the deep brain stimulation (DBS) system for epilepsy are favorable and demonstrate stable outcomes. Improvement in frequency of the most severe seizure type may reduce SUDEP risk. The SUDEP rate with DBS (2.0) is comparable to other neuromodulation treatments (i.e., vagus nerve stimulation, responsive neurostimulation) for drug-resistant focal epilepsy.

Perceptions of optimal end-of-life care in hospitals: A cross-sectional study of nurses in three locations.

AIM: To examine whether nurses' location of employment, demographics, or training influences their perceptions of what constitutes optimal care for dying patients in hospital. DESIGN: Questionnaire-based, cross-sectional study. METHODS: Between December 2016-June 2018, 582 registered or enrolled nurses from Australia (N = 153), South Korea (N = 241), and Hong Kong (N = 188) employed in a variety of hospital care units rated the extent to which they agreed with 29 indicators of optimal end-of-life care across four domains: patient, family, healthcare team, and healthcare system. Latent class analysis identified classes of respondents with similar responses. RESULTS: Top five indicators rated by participants included: 'physical symptoms managed well'; 'private rooms and unlimited visiting hours'; 'spend as much time with the patient as families wish'; 'end-of-life care documents stored well and easily accessed' and 'families know and follow patient's wishes'. Four latent classes were generated: 'Whole system/holistic' (Class 1); 'Patient/provider-dominated' (Class 2); 'Family-dominated' (Class 3) and 'System-dominated' (Class 4). Class 1 had the highest proportion of nurses responding positively for all indicators. Location was an important correlate of perceptions, even after controlling for individual characteristics. CONCLUSION: Nurses' perceptions of optimal end-of-life care are associated with location, but perhaps not in the direction that stereotypes would suggest. Findings highlight the importance of developing and implementing location-specific approaches to optimize end-of-life care in hospitals. IMPACT: The findings may be useful to guide education and policy initiatives in Asian and Western countries that stress that end-of-life care is more than symptom management. Indicators can be used to collect data that help quantify differences between optimal care and the care actually being delivered, thereby determining where improvements might be made.

Neuromodulation - Science and Practice in Epilepsy: Vagus Nerve Stimulation, Thalamic Deep Brain Stimulation, and Responsive NeuroStimulation.

Introduction: Neuromodulation devices can be safe and effective for the treatment of drug-resistant epilepsy. A body of scientific work supports peripheral, subcortical and cortical targets, each with different fundamental methods of action. Areas covered: High-quality evidence is available for vagal nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS). Mechanistic research in animals and human studies are reviewed, along with key data from VNS, DBS, and RNS clinical trials. Specifically, the authors review some of the science behind the most frequently used medical devices for neuromodulation, the evidence that lead to their adoption, a delineation of the populations that often benefit from these devices, and perspectives on clinical practice to optimize benefit in treatment of seizures. Expert Commentary: Neuromodulation is increasingly used to complement medical management of refractory epilepsy. Device preference will be made on the basis of patient preference, physician familiarity and other individualized factors. Right now, the field is very new and decision-making will improve with experience.

Frequency-selective control of cortical and subcortical networks by central thalamus.

Central thalamus plays a critical role in forebrain arousal and organized behavior. However, network-level mechanisms that link its activity to brain state remain enigmatic. Here, we combined optogenetics, fMRI, electrophysiology, and video-EEG monitoring to characterize the central thalamus-driven global brain networks responsible for switching brain state. 40 and 100 Hz stimulations of central thalamus caused widespread activation of forebrain, including frontal cortex, sensorimotor cortex, and striatum, and transitioned the brain to a state of arousal in asleep rats. In contrast, 10 Hz stimulation evoked significantly less activation of forebrain, inhibition of sensory cortex, and behavioral arrest. To investigate possible mechanisms underlying the frequency-dependent cortical inhibition, we performed recordings in zona incerta, where 10, but not 40, Hz stimulation evoked spindle-like oscillations. Importantly, suppressing incertal activity during 10 Hz central thalamus stimulation reduced the evoked cortical inhibition. These findings identify key brain-wide dynamics underlying central thalamus arousal regulation.

Stimulation of the medial septum should benefit patients with temporal lobe epilepsy.

Electrical stimulation of the septal nuclei via deep brain stimulating electrodes is proposed as a potentially beneficial therapy for medication-resistant temporal lobe epilepsy. In a multicenter study, stimulation of anterior thalamus was shown to reduce numbers of seizures, but decrease was only in the range of 40%. This might be improved with septal stimulation, which has strong and direct reciprocal connections with the hippocampal formation, the structure most involved in temporal lobe epilepsy. Medial septal neurons drive a 3-12 Hz theta rhythm in hippocampus of rodents. Theta rhythm is less obvious in human hippocampus, but it is present and it varies with cognitive tasks. The hippocampal theta rhythm is disrupted by seizures. In animal models, restoration of theta by sensory stimulation, septal electrical stimulation or cholinergic drugs infused into septum ameliorates seizures. Seizure activity in hippocampus is faithfully reflected in septal nuclei, and septum sometimes leads the seizure activity. A subset of patients with temporal lobe epilepsy have structural enlargement of their septal nuclei. At high levels of intensity, septal stimulation is subjectively pleasurable and strongly reinforcing. Rats will repeatedly press a bar to stimulate their septum. Initial experience with human septal stimulation in the 1950s was not favorable, with ineffective therapy for schizophrenia and a high rate of surgical complications. Subsequent experience in 50-100 pain patients employing modern neurosurgical techniques was more favorable and demonstrated septal stimulation to be safe and tolerable. The current state of knowledge is sufficient to consider design of a clinical trial of medial septal stimulation in selected patients with medication-resistant temporal lobe epilepsy.

Multimodality therapy and liver transplantation for hepatocellular carcinoma: a 14-year prospective analysis of outcomes.

BACKGROUND: Hepatocellular carcinoma is a major cause of death among patients with cirrhosis. A standardized approach of multimodality therapy with intent-to-treat by transplantation for all patients with hepatocellular carcinoma was instituted at our transplant center in 1997. Data were prospectively collected to evaluate the impact of multimodality therapy on posttransplant patient survival, tumor recurrence, and patient survival without transplantation. METHODS: All patients with hepatocellular carcinoma were eligible for multimodality therapy. Multimodality therapy consisted of hepatic resection, radiofrequency ablation, transarterial chemoembolization, transarterial chemoinfusion, yttrium-90 microsphere radioembolization, and sorafenib. RESULTS: Approximately 715 patients underwent multimodality therapy; 231 patients were included in the intent-to-treat with transplantation arm, and 484 patients were treated with multimodality therapy or palliative therapy because of contraindications for transplantation. A 60.2% transplantation rate was achieved in the intent-to-treat with transplantation arm. Posttransplant survivals at 1 and 5 years were 97.1% and 72.5%, respectively. Tumor recurrence rates at 1, 3, and 5 years were 2.4%, 6.2%, and 11.6%, respectively. Patients with contraindications to transplant had increased 1- and 5-year survival from diagnosis with multimodality therapy compared with those not treated (73.1% and 46.5% versus 15.5% and 4.4%, P<0.0001). CONCLUSIONS: Using multimodality therapy before liver transplantation for hepatocellular carcinoma achieved low recurrence rates and posttransplant survival equivalent to patients with primary liver disease without hepatocellular carcinoma. Multimodality therapy may help identify patients with less active tumor biology and result in improved disease-free survival and organ utilization.

Are we missing the Institute of Medicine's mark? A systematic review of patient-reported outcome measures assessing quality of patient-centred cancer care.

BACKGROUND: The Institute of Medicine (IOM) has endorsed six dimensions of patient-centredness as crucial to providing quality healthcare. These dimensions outline that care must be: 1) respectful to patients' values, preferences, and expressed needs; 2) coordinated and integrated; 3) provide information, communication, and education; 4) ensure physical comfort; 5) provide emotional support-relieving fear and anxiety; and 6) involve family and friends. However, whether patient-reported outcome measures (PROMs) comprehensively cover these dimensions remains unexplored. This systematic review examined whether PROMs designed to assess the quality of patient-centred cancer care addressed all six IOM dimensions of patient-centred care and the psychometric properties of these measures. METHODS: Medline, PsycINFO, Current Contents, Embase, CINAHL and Scopus were searched to retrieve published studies describing the development and psychometric properties of PROMs assessing the quality of patient-centred cancer care. Two authors determined if eligible PROMs included the six IOM dimensions of patient-centred care and evaluated the adequacy of psychometric properties based on recommended criteria for internal consistency, test-retest reliability, face/content validity, construct validity and cross-cultural adaptation. RESULTS: Across all 21 PROMs, the most commonly included IOM dimension of patient-centred care was "information, communication and education" (19 measures). In contrast, only five measures assessed the "involvement of family and friends." Two measures included one IOM-endorsed patient-centred care dimension, two measures had two dimensions, seven measures had three dimensions, five measures had four dimensions, and four measures had five dimensions. One measure, the Indicators (Non-small Cell Lung Cancer), covered all six IOM dimensions of patient-centred care, but had adequate face/content validity only. Eighteen measures met the recommended adequacy criteria for construct validity, 15 for face/content validity, seven for internal consistency, three for cross-cultural adaptation and no measure for test-retest reliability. CONCLUSIONS: There are no psychometrically rigorous PROMs developed with cancer patients that capture all six IOM dimensions of patient-centred care. Using more than one measure or expanding existing measures to cover all six patient-centred care dimensions could improve assessment and delivery of patient-centred care. Construction of new comprehensive measures with acceptable psychometric properties that can be used with the general cancer population may also be warranted.

Tobacco, alcohol and cannabis use during pregnancy: clustering of risks.

BACKGROUND: Antenatal substance use poses significant risks to the unborn child. We examined use of tobacco, alcohol and cannabis among pregnant Aboriginal and Torres Strait Islander women; and compared characteristics of women by the number of substances reported. METHODS: A cross-sectional survey with 257 pregnant Indigenous women attending antenatal services in two states of Australia. Women self-reported tobacco, alcohol and cannabis use (current use, ever use, changes during pregnancy); age of initiation of each substance; demographic and obstetric characteristics. RESULTS: Nearly half the women (120; 47% (95%CI:40%, 53%) reported no current substance use; 119 reported current tobacco (46%; 95%CI:40%, 53%), 53 (21%; 95%CI:16%, 26%) current alcohol and 38 (15%; 95%CI:11%, 20%) current cannabis use. Among 148 women smoking tobacco at the beginning of pregnancy, 29 (20%; 95%CI:14%, 27%) reported quitting; with 80 of 133 (60%; 95%CI:51%, 69%) women quitting alcohol and 25 of 63 (40%; 95%CI:28%, 53%) women quitting cannabis. Among 137 women reporting current substance use, 77 (56%; 95%CI:47%, 65%) reported one and 60 (44%; 95%CI:35%, 53%) reported two or three. Women using any one substance were significantly more likely to also use others. Factors independently associated with current use of multiple substances were years of schooling and age of initiating tobacco. CONCLUSIONS: While many women discontinue substance use when becoming pregnant, there is clustering of risk among a small group of disadvantaged women. Programmes should address risks holistically within the social realities of women's lives rather than focusing on individual tobacco smoking. Preventing uptake of substance use is critical.

How will we close the gap in smoking rates for pregnant Indigenous women?

Aboriginal and Torres Strait Islander women are more than three times more likely to smoke during pregnancy than non-Indigenous women, greatly increasing the risk of poor birth outcomes. Our systematic review found that there is currently no evidence for interventions that are effective in supporting pregnant Aboriginal and Torres Strait Islander women to quit smoking, which impedes development and implementation of evidence-informed policy and practice. There is an urgent need for methodologically rigorous studies to test innovative approaches to addressing this problem.

Randomized controlled trial of a ragweed allergy immunotherapy tablet in North American and European adults.

BACKGROUND: In North America and Europe, millions of patients experience symptoms of allergic rhinitis with or without conjunctivitis (AR/C) on exposure to ragweed pollen. The disease burden can be significant, with most patients relying on symptomatic medications without disease-modifying potential. However, novel sublingual immunomodulatory treatment options may potentially play an important role if efficacy and side effect profiles allow the convenience of self-administration. OBJECTIVES: This study evaluated an allergy immunotherapy tablet (AIT; SCH 39641/MK-3641) for treatment of ragweed-induced AR/C in the first large randomized, double-blind multinational trial of this therapeutic modality for ragweed allergy. METHODS: Adults (n = 784) with short ragweed-induced AR/C were randomly assigned to approximately 52 weeks of daily self-administered ragweed AIT of 1.5, 6, or 12 units of Ambrosia artemisiifolia major allergen 1 (Amb a 1-U) or placebo. Subjects could use as-needed allergy rescue medication. Symptoms and medications were recorded daily. The primary efficacy end point was total combined daily symptom/medication score (TCS) during peak ragweed season. Safety was monitored through adverse event diaries maintained through study duration. RESULTS: During peak ragweed season, ragweed AIT of 1.5, 6, and 12 Amb a 1-U reduced TCS by 9% (-0.76; P = .22), 19% (-1.58; P = .01), and 24% (-2.04; P = .002) compared with placebo. During the entire season, ragweed AIT of 1.5, 6, and 12 Amb a 1-U reduced TCS by 12% (-0.88; P = .09), 18% (-1.28; P = .01), and 27% (-1.92; P < .001) compared with placebo. Treatment was well tolerated; no systemic allergic reactions occurred. CONCLUSIONS: In this trial, ragweed AIT of 12 Amb a 1-U was effective and tolerable with a safety profile that permitted daily self-administration of ragweed allergen immunotherapy.

Why minimal is not optimal: driving the mammalian cell cycle--and drug discovery--with a physiologic CDK control network.

Progression through the eukaryotic cell division cycle is governed by the activity of cyclin-dependent kinases (CDKs). For a CDK to become active it must (1) bind a positive regulatory subunit (cyclin) and (2) be phosphorylated on its activation (T) loop. In metazoans, multiple CDK catalytic subunits, each with a distinct set of preferred cyclin partners, regulate the cell cycle, but it has been difficult to assign functions to individual CDKs in vivo. Biochemical analyses and experiments with dominant-negative alleles suggested that specific CDK/cyclin complexes regulate different events, but genetic loss of interphase CDKs (Cdk2, -4 and -6), alone or in combination, did not block proliferation of cells in culture. These knockout and knockdown studies suggested redundancy or plasticity built into the CDK network but did not address whether there was true redundancy in normal cells with a full complement of CDKs. Here, we discuss recent work that took a chemical-genetic approach to reveal that the activity of a genetically non-essential CDK, Cdk2, is required for cell proliferation when normal cyclin pairing is maintained. These results have implications for the systems-level organization of the cell cycle, for regulation of the restriction point and G 1/S transition and for efforts to target Cdk2 therapeutically in human cancers.

Therapeutic devices for epilepsy.

Therapeutic devices provide new options for treating drug-resistant epilepsy. These devices act by a variety of mechanisms to modulate neuronal activity. Only vagus nerve stimulation (VNS), which continues to develop new technology, is approved for use in the United States. Deep brain stimulation of anterior thalamus for partial epilepsy recently was approved in Europe and several other countries. Responsive neurostimulation, which delivers stimuli to 1 or 2 seizure foci in response to a detected seizure, recently completed a successful multicenter trial. Several other trials of brain stimulation are in planning or underway. Transcutaneous magnetic stimulation (TMS) may provide a noninvasive method to stimulate cortex. Controlled studies of TMS are split on efficacy, which may depend on whether a seizure focus is near a possible region for stimulation. Seizure detection devices in the form of shake detectors via portable accelerometers can provide notification of an ongoing tonic-clonic seizure, or peace of mind in the absence of notification. Prediction of seizures from various aspects of electroencephalography (EEG) is in early stages. Prediction appears to be possible in a subpopulation of people with refractory seizures, and a clinical trial of an implantable prediction device is underway. Cooling of neocortex or hippocampus reversibly can attenuate epileptiform EEG activity and seizures, but engineering problems remain in its implementation. Optogenetics is a new technique that can control excitability of specific populations of neurons with light. Inhibition of epileptiform activity has been demonstrated in hippocampal slices, but use in humans will require more work. In general, devices provide useful palliation for otherwise uncontrollable seizures, but with a different risk profile than with most drugs. Optimizing the place of devices in therapy for epilepsy will require further development and clinical experience.

Electrical stimulation of the anterior nucleus of thalamus for treatment of refractory epilepsy.

PURPOSE: We report a multicenter, double-blind, randomized trial of bilateral stimulation of the anterior nuclei of the thalamus for localization-related epilepsy. METHODS: Participants were adults with medically refractory partial seizures, including secondarily generalized seizures. Half received stimulation and half no stimulation during a 3-month blinded phase; then all received unblinded stimulation. RESULTS: One hundred ten participants were randomized. Baseline monthly median seizure frequency was 19.5. In the last month of the blinded phase the stimulated group had a 29% greater reduction in seizures compared with the control group, as estimated by a generalized estimating equations (GEE) model (p = 0.002). Unadjusted median declines at the end of the blinded phase were 14.5% in the control group and 40.4% in the stimulated group. Complex partial and "most severe" seizures were significantly reduced by stimulation. By 2 years, there was a 56% median percent reduction in seizure frequency; 54% of patients had a seizure reduction of at least 50%, and 14 patients were seizure-free for at least 6 months. Five deaths occurred and none were from implantation or stimulation. No participant had symptomatic hemorrhage or brain infection. Two participants had acute, transient stimulation-associated seizures. Cognition and mood showed no group differences, but participants in the stimulated group were more likely to report depression or memory problems as adverse events. DISCUSSION: Bilateral stimulation of the anterior nuclei of the thalamus reduces seizures. Benefit persisted for 2 years of study. Complication rates were modest. Deep brain stimulation of the anterior thalamus is useful for some people with medically refractory partial and secondarily generalized seizures.

Assembly properties of human immunodeficiency virus type 1 Gag-leucine zipper chimeras: implications for retrovirus assembly.

Expression of the retroviral Gag protein leads to formation of virus-like particles in mammalian cells. In vitro and in vivo experiments show that nucleic acid is also required for particle assembly. However, several studies have demonstrated that chimeric proteins in which the nucleocapsid domain of Gag is replaced by a leucine zipper motif can also assemble efficiently in mammalian cells. We have now analyzed assembly by chimeric proteins in which nucleocapsid of human immunodeficiency virus type 1 (HIV-1) Gag is replaced by either a dimerizing or a trimerizing zipper. Both proteins assemble well in human 293T cells; the released particles lack detectable RNA. The proteins can coassemble into particles together with full-length, wild-type Gag. We purified these proteins from bacterial lysates. These recombinant "Gag-Zipper" proteins are oligomeric in solution and do not assemble unless cofactors are added; either nucleic acid or inositol phosphates (IPs) can promote particle assembly. When mixed with one equivalent of IPs (which do not support assembly of wild-type Gag), the "dimerizing" Gag-Zipper protein misassembles into very small particles, while the "trimerizing" protein assembles correctly. However, addition of both IPs and nucleic acid leads to correct assembly of all three proteins; the "dimerizing" Gag-Zipper protein also assembles correctly if inositol hexakisphosphate is supplemented with other polyanions. We suggest that correct assembly requires both oligomeric association at the C terminus of Gag and neutralization of positive charges near its N terminus.

Predictive factors for clinical improvement with Enterra gastric electric stimulation treatment for refractory gastroparesis.

UNLABELLED: The objectives of this study were to determine the clinical response to Enterra gastric electric stimulation (GES) in patients with refractory gastroparesis and to determine factors associated with a favorable response. METHODS: This study was conducted in patients undergoing Enterra GES for refractory gastroparesis. Symptoms were scored before and after GES implantation using the Gastroparesis Cardinal Symptom Index (GCSI) with additional questions about abdominal pain and global clinical response. RESULTS: During an 18-month period, 29 patients underwent GES implantation. Follow-up data were available for 28 patients, with average follow-up of 148 days. At follow-up, 14 of 28 patients felt improved, 8 remained the same, and 6 worsened. The overall GCSI significantly decreased with improvement in the nausea/vomiting subscore and the post-prandial subscore, but no improvement in the bloating subscore or abdominal pain. The decrease in GCSI was greater for diabetic patients than idiopathic patients. Patients with main symptom of nausea/vomiting had a greater improvement than patients with the main symptom of abdominal pain. Patients taking narcotic analgesics at the time of implant had a poorer response compared to patients who were not. CONCLUSIONS: GES resulted in clinical improvement in 50% of patients with refractory gastroparesis. Three clinical parameters were associated with a favorable clinical response: (1) diabetic rather than idiopathic gastroparesis, (2) nausea/vomiting rather than abdominal pain as the primary symptom, and (3) independence from narcotic analgesics prior to stimulator implantation. Knowledge of these three factors may allow improved patient selection for GES.