Long-term efficacy and safety of tonic motor activation for treatment of medication-refractory restless legs syndrome: A 24-Week Open-Label Extension Study

STUDY OBJECTIVES

To evaluate long-term efficacy and safety of tonic motor activation (TOMAC) for treatment of medication-refractory moderate-to-severe primary restless legs syndrome (RLS).

METHODS

In the parent study (RESTFUL), adults with refractory RLS were randomized to active TOMAC or sham for 4 weeks followed by 4 weeks of open-label active TOMAC. In the extension study, earlier RESTFUL completers comprised the control group (n = 59), which was followed for 24 weeks with no TOMAC intervention, and later RESTFUL completers compromised the treatment group (n = 44), which received 24 additional weeks of open-label active TOMAC followed by no intervention for 8 weeks. The primary endpoint was Clinician Global Impressions-Improvement (CGI-I) responder rate at week 24 compared to RESTFUL entry.

RESULTS

CGI-I responder rate improved from 63.6% (95% CI, 49.4 to 77.9%) at RESTFUL completion to 72.7% (95% CI, 58.2 to 83.7%) at week 24 for the treatment group versus 13.6% (95% CI, 7.0 to 24.5%) at week 24 for the control group (p < 0.0001). Mean change in International RLS Rating Scale (IRLS) score improved from -7.4 (95% CI, -5.6 to -9.2) at RESTFUL completion to -11.3 points (95% CI, -8.8 to -13.9) at week 24 for the treatment group versus -5.4 (95% CI, -3.7 to -7.2) at week 24 for control group (p = 0.0001). All efficacy endpoints partially reverted during cessation of treatment. There were no grade 2 or higher device-related adverse events.

CONCLUSIONS

TOMAC remained safe and efficacious for >24 total weeks of treatment with partial reversion of benefits upon cessation.

CLINICAL TRIAL

Extension Study Evaluating NTX100 Neuromodulation System for Medication-Refractory Primary RLS; clinicaltrials.gov/ct2/show/NCT05196828; Registered at ClinicalTrials.gov with the identifier number NCT05196828.

Efficacy and safety of tonic motor activation (TOMAC) for medication-refractory restless legs syndrome: a randomized clinical trial

STUDY OBJECTIVES

The purpose of this study was to evaluate the efficacy and safety/tolerability of bilateral high-frequency tonic motor activation (TOMAC) in patients with medication-refractory restless legs syndrome (RLS).

METHODS

RESTFUL was a multicenter, randomized, double-blind, sham-controlled trial in adults with medication-refractory moderate-to-severe primary RLS. Participants were randomized 1:1 to active or sham TOMAC for a double-blind, 4-week stage 1 and all received active TOMAC during open-label, 4-week stage 2. The primary endpoint was the Clinical Global Impressions-Improvement (CGI-I) responder rate at the end of stage 1. Key secondary endpoints included change to International RLS Study Group (IRLS) total score from study entry to the end of stage 1.

RESULTS

A total of 133 participants were enrolled. CGI-I responder rate at the end of stage 1 was significantly greater for the active versus sham group (45% vs. 16%; Difference = 28%; 95% CI 14% to 43%; p = .00011). At the end of stage 2, CGI-I responder rate further increased to 61% for the active group. IRLS change at the end of stage 1 improved for the active versus sham group (-7.2 vs. -3.8; difference = -3.4; 95% CI -1.4 to -5.4; p = .00093). There were no severe or serious device-related adverse events (AEs). The most common AEs were mild discomfort and mild administration site irritation which resolved rapidly and reduced in prevalence over time.

CONCLUSIONS

TOMAC was safe, well tolerated, and reduced symptoms of RLS in medication-refractory patients. TOMAC is a promising new treatment for this population.

CLINICAL TRIAL

Noninvasive Peripheral Nerve Stimulation for Medication-Refractory Primary RLS (The RESTFUL Study); clinicaltrials.gov/ct2/show/NCT04874155; Registered at ClinicalTrials.gov with the identifier number NCT04874155.

Loss-of-function genetics in mammalian cells: the p53 tumor suppressor model

Using an improved system for the functional identification of active antisense fragments, we have isolated antisense fragments which inactivate the p53 tumour suppressor gene. These antisense fragments map in two small regions between nt 350 and 700 and nt 800 and 950 of the coding sequence. These antisense fragments appear to act by inhibition of p53 mRNA translation both in vivo and in vitro. Expression of these antisense fragments overcame the p53-induced growth arrest in a cell line which expresses a thermolabile mutant of p53 and extended the in vitro lifespan of primary mouse embryonic fibroblasts. Continued expression of the p53 antisense fragment contributed to immortalisation of primary mouse fibroblasts. Subsequent elimination of the antisense fragment in these immortalised cells led to restoration of p53 expression and growth arrest, indicating that immortal cells continuously require inactivation of p53. Expression of MDM2 or SV40 large T antigen, but not E7 nor oncogenic ras, overcomes the arrest induced by restoration of p53 expression. Functional inactivation of both p21 and bax (by overexpression of Bcl2), but not either alone, allowed some bypass of p53-induced growth arrest, indicating that multiple transcriptional targets of p53 may mediate its antiproliferative action. The ability to conditionally inactivate and subsequently restore normal gene function may be extremely valuable for genetic analysis of genes for which loss-of-function is involved in specific phenotypes.

p16INK4A and p19ARF act in overlapping pathways in cellular immortalization

The INK4A locus encodes two independent but overlapping genes, p16INK4A and p19ARF, and is frequently inactivated in human cancers. The unusual structure of this locus has lead to ambiguity regarding the biological role of each gene. Here we express, in primary mouse embryonic fibroblasts (MEFs), antisense RNA constructs directed specifically towards either p16INK4A or p19 ARF. Such constructs induce extended lifespan in primary MEFs; this lifespan extension is reversed upon subsequent elimination of the p16INK4A or p19ARF antisense constructs. In immortal derivatives of cell lines expressing antisense p16INK4A or p19ARF RNA, growth arrest induced by recovery of p16INK4A expression is bypassed by compromising the function of the retinoblastoma protein (Rb), whereas growth arrest induced by re-expression of p19ARF is overcome only by simultaneous inactivation of both the Rb and the p53 pathways. Thus, the physically overlapping p16INK4A and p19ARF genes act in partly overlapping pathways.

Enamel wear caused by three different restorative materials

The ideal restorative material should cause minimal wear of opposing enamel. This study compared the effects of gold alloy, glazed porcelain, and a laboratory-processed composite on opposing enamel. Ten samples of a type III gold alloy, a porcelain, and a visible-light, heat, and vacuum-processed composite were abraded against cusps of extracted molars for 10,000 cycles on an abrading machine. Pretest and posttest profilometric measurements of the restorative materials demonstrated no statistical difference. Pretest and posttest tracings of the cusps were made on an optical comparator to determine loss of vertical height and surface area. The porcelain caused significantly more loss of vertical height and surface area than the gold alloy or the composite, which were similar.

Evaluation of multiple-marker screening for Down syndrome in a statewide population

OBJECTIVE

Our purpose was to evaluate our experience with a statewide, multiple-marker Down syndrome screening program.

STUDY DESIGN

The results of 18,712 screening tests performed from July 1, 1991, to Oct. 31, 1992, were reviewed. Amniocentesis and aneuploidy detection rates were compared with the experience of a previous year (1989-1990) in which material serum alpha-fetoprotein was used for detection of Down syndrome.

RESULTS

Positive screening tests (Down syndrome risk > or = 1/190) occurred in 665 of 18,712 (3.5%) patients; 516 of 665 (78%) patients accepted amniocentesis. Fifteen aneuploidies were identified: 12 trisomy 21, one trisomy 18, one trisomy 13, and one 48,XXXY. The overall detection rate was one in 34 amniocenteses performed; for trisomy 21 it was one in 43. In a previous year in which maternal serum alpha-fetoprotein alone was used, 3.6% had positive screening tests (Down syndrome risk > or = 270); the detection rate for all aneuploidies was one in 57 amniocenteses, and for trisomy 21 it was one in 114. The expanded maternal serum alpha-fetoprotein test was well accepted by clinicians, with 36% of gravid state residents undergoing screening.

CONCLUSION

The multiple marker test is a good screening tool and is superior to material serum alpha-fetoprotein alone.

Sequence of the Schizosaccharomyces pombe gtp1 gene and identification of a novel family of putative GTP-binding proteins

A new gene, gtp1, has been identified by sequence analysis in Schizosaccharomyces pombe. The open reading frame was identified downstream from the stf1 locus. The deduced GTP1 protein has strong sequence similarity to a family of putative GTP-binding proteins from Halobacterium cutirubrum, Bacillus subtilis, Drosophila melanogaster and mouse. The conserved P-loop phosphate-binding motif places gtp1 in a family separate from previously described groups of such proteins.

The disparity between hypothermic coagulopathy and clotting studies

Hypothermic patients commonly develop coagulopathy, but the effects of hypothermia on coagulation remain unclear because clinical laboratories routinely perform clotting tests only at 37 degrees C. Measurements of activated partial thromboplastin times (APTT), prothrombin times (PT), and thrombin times (TT) were performed on plasma from normothermic and hypothermic rats at a range of temperatures (25 degrees-37 degrees C) to assess the effects of hypothermia on apparent clotting factor levels and clotting factor activities. In general, clotting times were more severely prolonged when test temperatures were hypothermic than when body temperatures were hypothermic. Indeed, little to no prolongation resulted from body hypothermia alone. These findings reveal the observed disparity between clinically evident hypothermic coagulopathy and near-normal clotting studies. Clotting studies performed at 37 degrees C will not confirm hypothermic coagulopathy. These results indicate that the appropriate treatment for hypothermia-induced coagulopathy is rewarming rather than administration of clotting factors.

stf1: a new suppressor of the mitotic control gene, cdc25, in Schizosaccharomyces pombe

A novel element in the mitotic control, stf1, has been identified genetically by its ability to rescue cdc25-22 as well as a gene disruption of cdc25. This is the first phenotypically non-wee mutation shown to do so. stf1-1 functions additively with cdc2-1w, cdc2-3w, or wee1-6 to rescue cdc25. The available data are consistent with the wild-type gene product operating either on the same pathway as cdc25 or to stimulate cdc2 by a pathway independent of cdc25 or wee1. The stf1 gene has been cloned and sequenced and encodes a putative protein of 50-65 kD, depending on whether a potential intron is present. It is a novel protein with no homology detected in the current data bases. When challenged with hydroxyurea, stf1-1 acts additively with cdc2-3w in rescuing cdc25 mutants and in allowing mitosis to occur without DNA synthesis. It does not appear to play a role in the nutritional sensing pathway nor in the pathway mediating radiation-induced G2 delay.

stf1: non-wee mutations epistatic to cdc25 in the fission yeast Schizosaccharomyces pombe

In Schizosaccharomyces pombe, cdc25 is a cell cycle regulated inducer of mitosis. wee1 and phenotypically wee alleles of cdc2 are epistatic to cdc25. Mutant alleles of a new locus, stf1 (suppressor of twenty-five), identified in a reversion analysis of conditionally lethal cdr1-76 cdc25-22 and cdr2-96 cdc25-22 double mutant strains, also suppress both temperature-sensitive and gene disruption alleles of cdc25. These mutants, by themselves, are phenotypically indistinguishable from wild type strains; hence they represent the first known mutations that are epistatic to cdc25 and do not display a wee phenotype. stf1 genetically interacts with other elements of mitotic control in S. pombe. stf1-1 is additive with wee1-50, cdc2-1w and cdc2-3w for suppression of cdc25-22. Also, like wee1- and cdc2-w, stf1- suppression of cdc25 is reversed by overexpression of the putative type 1 protein phosphatase bws1+/dis2+. Interaction with various mutants and plasmid overexpression experiments suggest that stf1 does not operate either upstream or downstream of wee1. Similarly, it does not operate through cdc25 since it rescues the disruption. stf1 appears to encode an important new element of mitotic control.

Hypothermia and blood coagulation: dissociation between enzyme activity and clotting factor levels

Previous studies of hypothermia and blood coagulation have focused on alterations in the levels of blood clotting elements using coagulation tests performed under normothermic conditions. However, because of the enzymatic nature of activated clotting factors, hypothermia should also be expected to affect clotting factor activities. Multiple determinations of activated partial thromboplastin times (APTT), prothrombin times (PT), and thrombin times (TT) were performed on commercially available normal human plasma at assay temperatures similar to those encountered clinically (25-37 degrees C). Both the APTT and the PT were significantly prolonged at temperatures below 35 degrees C (P less than 0.05). Clotting time correlated significantly with assay temperature in a negative exponential fashion for all three tests (r = -0.97 for APTT, -0.93 for PT, -0.71 for TT, P less than 0.001 for all regressions). Clotting time prolongation appears proportional to the number of enzymatic steps involved. These data indicate that the coagulopathy observed during hypothermia is, in part, independent of clotting factor levels.

Peer review: indictment, trial and beyond

The authors discuss the disciplinary process created by the Peer Review Improvement Act and problems it causes for the practitioner.

Evaluation of MUREX SUDS Toxo test

The SUDS Toxo test (MUREX Corp., Norcross, Ga.) was compared with the indirect hemagglutination test (IHA) and the indirect fluorescent-antibody test (IFA) by examining 404 serum specimens, including 64 (15.8%) specimens with IFA titers of greater than or equal to 1:2. When SUDS was compared with IHA, sensitivity (96.4%), specificity (97.9%), and negative predictive value (99.4%) indicated that there were similar reactivities between the two tests. When an IFA titer of greater than or equal to 1:16 was considered significant and IHA and SUDS were compared with IFA, IHA was slightly less sensitive but had a higher positive predictive value than did SUDS; however, there was no statistical difference between the tests. When SUDS was compared with IFA, in which a titer of greater than or equal to 1:16 was considered significant, the high negative predictive value (100%), excellent sensitivity (100%) and specificity (98.3%), and ease of performance made SUDS an attractive alternative to IHA for screening single serum specimens for toxoplasmosis.

Comparison of serologic screening tests for brucellosis

The slide agglutination test (SAT), microagglutination test (MAT), and card agglutination test (CAT) were compared with each other, using the tube agglutination test (TAT) as the standard method, by two reference laboratories to determine effectiveness as screening tests for human brucellosis. TAT titers of 1,253 sera tested in both laboratories were compared. In one laboratory, 1,270 sera were tested by the TAT and SAT, while the other laboratory tested 1,261 sera by both methods. Of these sera, 1,155 were tested in one laboratory by the CAT and 187 sera were tested by the MAT. Compared with that of the TAT (greater than or equal to 160 positive), the sensitivities were 97 to 100% (SAT), 90% (CAT), and 88% (MAT). The specificities were 88 to 89% (SAT), 98% (CAT), and 88% (MAT). For populations with a low prevalence of disease, increased specificity offers higher predictive value, so the CAT and MAT are preferable for screening purposes and the choice between tests depends on the number and frequency of tests performed. All sera reactive in the CAT and MAT should be retested with the TAT.

Evaluation of the Bio-EnzaBead test for syphilis

The sensitivity and specificity of the Bio-EnzaBead test for syphilis and the fluorescent treponemal antibody-absorption (FTA-ABS) test were determined by examining 262 serum samples, including 202 serum samples from patients with confirmed syphilis in various stages. Overall correlation with patient history was 95.8% with both tests. False-negative Bio-EnzaBead tests occurred in 9 of 86 (10.5%) cases of late-latent syphilis (greater than 2 years) and in 1 of 38 (2.6%) cases for which the stage of disease could not be determined. False-negative FTA-ABS tests occurred in 5 of 86 (5.8%) cases of late-latent syphilis (greater than 2 years) and in 2 of 38 (5.3%) cases for which the stage of disease could not be determined. One false-positive test occurred with Bio-EnzaBead, and the cause could not be determined. The reproducibility of the Bio-EnzaBead test was excellent when spectrophotometric readings were calibrated against either air or substrate blanks. The Bio-EnzaBead test for syphilis is a suitable alternative to the FTA-ABS test.

Effects of pesticides and drugs on working memory in rats: continuous non-match

Effects of four pesticides (carbaryl, propoxur, chlordimeform, and deltamethrin) and two reference drugs, physostigmine and chlordiazepoxide, were measured on the performance of rats trained on a continuous non-match (CNM) delayed comparison, working memory procedure. These same compounds were also tested in analogous, large and small stimulus difference discrimination (i.e., non working-memory) procedures. The effects of the pesticides and physostigmine on CNM performance were qualitatively similar, and also similar to their effects on discrimination performance. As dosage of these compounds increased, only small effects on accuracy were observed, followed at still larger doses by an abrupt and non-selective decrease in all responding. The pesticides and physostigmine did not selectively affect working memory: the magnitude of their effects did not increase with intertrial interval, and the compounds were equally effective in disrupting discrimination and CNM performance. Effects of chlordiazepoxide on performance in the CNM and discrimination control procedures differed qualitatively from those of the pesticides and physostigmine.

Effects of pesticides and drugs on working memory in rats: continuous delayed response

Effects of four pesticides (carbaryl, propoxur, chlordimeform, and deltamethrin) and four reference drugs (physostigmine, scopolamine, methscopolamine, and chlordiazepoxide) were measured in two delayed response, working memory procedures: go-no go alternation in which rats initiated their own trials, and spatial reversals. Four of these compounds (carbaryl, propoxur, physostigmine, and scopolamine) were also tested in a go-no go alternation procedure in which animals did not initiate their trials. The pesticides and physostigmine did not selectively affect working memory in any of the procedures: low doses only moderately decreased response accuracy, whereas higher doses suppressed responding indiscriminately. The pesticides and physostigmine had similar effects on go-no go alternation (i.e., working memory) and analogous go-no go discrimination performance. Effects on go-no go alternation performance did not depend on whether the animals initiated their own trials. Scopolamine, in contrast, appeared to disrupt working memory. It profoundly disrupted accuracy at doses that only moderately decreased over-all responding and impaired go-no go alternation accuracy much more than discrimination accuracy.

Epithelial mediated wound contraction in experimental wounds--the purse-string effect

Wound contraction, a process whereby wound edges are drawn together, is thought to be mediated by the myofibroblast cell population. However, experimental wounds may close as much as 25% (surface area) before the onset of fibroplasia which is marked by the migration of fibroblasts and myofibroblasts into the wound bed 2 to 3 days after injury. This early phase of wound closure appears to be mediated by a contractile force produced by a circumferentially arranged band of fusiform-shaped epidermal cells situated in the wound margin. Cytoplasmic microfilaments in the epidermal cells, similar in size and configuration to actin filaments and/or tonofilaments, are found to be aligned with the long axis of the constitutive cells comprising the contractile band. The data suggest that contraction in experimental wounds is promoted by at least two distinct cell-mediated contractile events: an initial although brief phase effected by cells of the epidermis followed by an extended phase of soft connective tissue contraction produced vis à vis the myofibroblasts in the dermis.

Evaluation of the hemagglutination treponemal test for syphilis

The sensitivity and specificity of the hemagglutination treponemal test for syphilis (HATTS) was compared with the fluorescent treponemal antibody-absorption test (FTA-ABS) with 491 sera. Medical histories were obtained for 153 patients with seroreactivity in either treponemal test. Overall correlation with patient history was 96.7% for the FTA-ABS and 93.9% for the HATTS. False-negative HATTS occurred in primary, late-latent (greater than 2 years), and treated syphilis. The reproducibility of the HATTS and FTA-ABS is equivalent. HATTS is an acceptable treponemal confirmatory test for syphilis, but the FTA-ABS should be used to resolve diagnostic discrepancies.