Intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: a prospective randomized double-blind sham-controlled multi-center study.

PURPOSE: To evaluate the safety and efficacy of radiofrequency (RF) ablation of the basivertebral nerve (BVN) for the treatment of chronic low back pain (CLBP) in a Food and Drug Administration approved Investigational Device Exemption trial. The BVN has been shown to innervate endplate nociceptors which are thought to be a source of CLBP. METHODS: A total of 225 patients diagnosed with CLBP were randomized to either a sham (78 patients) or treatment (147 patients) intervention. The mean age within the study was 47 years (range 25-69) and the mean baseline ODI was 42. All patients had Type I or Type II Modic changes of the treated vertebral bodies. Patients were evaluated preoperatively, and at 2 weeks, 6 weeks and 3, 6 and 12 months postoperatively. The primary endpoint was the comparative change in ODI from baseline to 3 months. RESULTS: At 3 months, the average ODI in the treatment arm decreased 20.5 points, as compared to a 15.2 point decrease in the sham arm (p = 0.019, per-protocol population). A responder analysis based on ODI decrease ≥ 10 points showed that 75.6% of patients in the treatment arm as compared to 55.3% in the sham control arm exhibited a clinically meaningful improvement at 3 months. CONCLUSION: Patients treated with RF ablation of the BVN for CLBP exhibited significantly greater improvement in ODI at 3 months and a higher responder rate than sham treated controls. BVN ablation represents a potential minimally invasive treatment for the relief of chronic low back pain. These slides can be retrieved under Electronic Supplementary Material.

Therapeutic efficacy in a hemophilia B model using a biosynthetic mRNA liver depot system.

DNA-based gene therapy has considerable therapeutic potential, but the challenges associated with delivery continue to limit progress. Messenger RNA (mRNA) has the potential to provide for transient production of therapeutic proteins, without the need for nuclear delivery and without the risk of insertional mutagenesis. Here we describe the sustained delivery of therapeutic proteins in vivo in both rodents and non-human primates via nanoparticle-formulated mRNA. Nanoparticles formulated with lipids and lipid-like materials were developed for delivery of two separate mRNA transcripts encoding either human erythropoietin (hEPO) or factor IX (hFIX) protein. Dose-dependent protein production was observed for each mRNA construct. Upon delivery of hEPO mRNA in mice, serum EPO protein levels reached several orders of magnitude (>125 000-fold) over normal physiological values. Further, an increase in hematocrit (Hct) was established, demonstrating that the exogenous mRNA-derived protein maintained normal activity. The capacity of producing EPO in non-human primates via delivery of formulated mRNA was also demonstrated as elevated EPO protein levels were observed over a 72-h time course. Exemplifying the possible broad utility of mRNA drugs, therapeutically relevant amounts of human FIX (hFIX) protein were achieved upon a single intravenous dose of hFIX mRNA-loaded lipid nanoparticles in mice. In addition, therapeutic value was established within a hemophilia B (FIX knockout (KO)) mouse model by demonstrating a marked reduction in Hct loss following injury (incision) to FIX KO mice.

Two missense mutations in melanocortin 1 receptor (MC1R) are strongly associated with dark ventral coat color in reindeer (Rangifer tarandus).

The protein-coding region of melanocortin 1 receptor (MC1R) was sequenced to identify potential variation affecting coat color in reindeer (Rangifer tarandus). A T→C sequence variation at nucleotide position 218 (c.218T>C) causing an amino acid (aa) change from methionine to threonine at aa position 73 (p.Met73Thr) was identified. In addition, a T→G sequence variation was found at nucleotide position 839 (c.839T>G), causing phenylalanine to be exchanged by cysteine at aa position 280 (p.Phe280Cys). The two sequence variants (c.218C and c.839G) were found to be closely associated with a darker belly coat compared with animals not having any of these two variants. The aa acid change p.Met73Thr affects the same position as p.Met73Lys previously reported to give constitutive activation of MC1R in black sheep (Ovis aries), whereas p.Phe280Cys is identical to one of two variants previously reported to be associated with dark coat color in Arctic fox (Alopex lagopus), supporting that the two variants found in reindeer are functional. The complete absence of Thr73 and Cys280 among the 51 wild reindeer analyzed provides some evidence that these variants are more common in the domestic herds.

Minimally invasive surgery for the lumbar spine.

Minimally invasive spine surgery is a rapidly developing field that has the potential to decrease surgical morbidity and improve recovery compared to traditional spinal approaches. Minimally invasive approaches have been developed for all regions of the spine, but have been best documented for degenerative conditions of the lumbar spine. Lumbar decompression and lumbar interbody fusion are two of the most well-studied minimally invasive surgical approaches. This article will review both the rationale and technique for minimally invasive lumbar decompression and for a minimally invasive transforaminal lumbar interbody fusion (TLIF).

Augmentation of Pedicle Screws Using Bone Grafting in Patients with Spinal Osteoporosis.

The aim of the study was to develop a new method of vertebral augmentation based on autologous and allogeneic bone chips to be used in pedicle screw fixation and to compare this method with the technique based on polymethyl methacrylate (PMMA). Materials and Methods: This prospective non-randomized study included 164 patients with degenerative pathologies or traumatic injuries of the lumbar spine and transitional thoracolumbar segments; 153 of the operated patients were followed up for 18 months. In these patients, radiodensity of the cancellous bone tissue was below 110 HU by the Hounsfield scale. Patients with degenerative spinal disorders underwent pedicle screw fixation using transforaminal interbody fusion; patients with traumatic spinal injuries underwent intermediate pedicle screw fixation, and those with a loss of vertebral body height by >50% underwent anterior fusion.The patients were divided into three groups: in group 1 (n=39), bone tissue augmentation was performed using PMMA; in group 2 (n=21), augmentation was done with bone chips; in group 3 (n=93), no augmentation was performed (control group). The follow-up period was 12 months; cases with fixator breakage or loosening were recorded. Results: After augmentation with PMMA, 11 cases (28.2%) of fixator destabilization were detected. With bone chips, fixator instability developed in 2 patients (9.5%) only, whereas in patients operated without augmentation, the instability was observed in 43 cases (46.2%). With PMMA augmentation, the incidence rate of fixator destabilization did not significantly differ from that in the control group (p=0.0801), while the use of bone chips resulted in a statistically significant decrease of this index compared to the control group (p=0.0023). A logistic regression analysis confirmed the superiority of the developed method over the PMMA-based vertebral augmentation. Conclusion: The use of bone chips for vertebral augmentation provides a statistically significant decrease in the incidence of pedicle screw fixator destabilization in the post-operative period. By reducing the risk of proximal loosening and eliminating the risk of bone cement drainage into the spinal canal and vascular bed, the proposed method may become especially effective in patients with impaired bone density.

Lipid-based nanotherapeutics for siRNA delivery.

RNA interference (RNAi) is a specific gene-silencing mechanism triggered by small interfering RNA (siRNA). The application of RNAi in the clinic requires the development of safe and effective delivery systems. Inspired by progress with lipid-based systems in drug delivery, efforts have been dedicated to the development of liposomal siRNA delivery systems. Many of the lipid-based delivery vehicles self-assemble with siRNA through electrostatic interactions with charged amines, generating multi-lamellar lipoplexes with positively charged lipid bilayers separated from one another by sheets of negatively charged siRNA strands. Internalization of lipid-based siRNA delivery systems into cells typically occurs through endocytosis; accordingly, delivery requires materials that can facilitate endosomal escape. The size of the carrier is important as carriers <100 nm in diameter have been reported to have higher accumulation levels in tumours, hepatocytes and inflamed tissue, whereas larger particles tend to be taken up by Kupffer cells or other components of the reticuloendothelial system (RES). To reduce RES uptake and increase circulation time, carriers have been modified on the surface with hydrophilic materials, such as polyethyleneglycol. Herein, we review the molecular and structural parameters of lipid-based siRNA delivery systems.

Gene delivery to human adult and embryonic cell-derived stem cells using biodegradable nanoparticulate polymeric vectors.

Gene delivery to stem cells holds great potential for tissue regeneration and delivery of therapeutic proteins. The major barrier is the lack of safe and efficient delivery methods. Here, we report enhanced gene delivery systems for human stem cells using biodegradable polymeric vectors. A library of poly (beta-amino esters) end-modified derivatives was developed and optimized for high transfection efficiency and low cytotoxicity for three human stem cell lines including human mesenchymal stem cells (hMSCs), human adipose-derived stem cells (hADSCs) and human embryonic stem cell-derived cells (hESCds). In the presence of 10% serum, leading end-modified C32 polymeric vectors exhibited significantly high transfection efficiency in hMSCs (27+/-2%), hADSCs (24+/-3%) and hESCds (56+/-11%), with high cell viability (87-97%) achieved in all cell types. Our results show that poly(beta-amino esters) as a class, and end-modified versions of C32 in particular, are efficient polymeric vectors for gene delivery to both adult and embryonic-derived stem cells.

Inhibition of the oxidative metabolism of 3,4-dihydroxyphenylacetaldehyde, a reactive intermediate of dopamine metabolism, by 4-hydroxy-2-nonenal.

Recent evidence indicates a role for oxidative stress and resulting products, e.g. 4-hydroxy-2-nonenal (4HNE) in the pathogenesis of Parkinson's disease (PD). 4HNE is a known inhibitor of mitochondrial aldehyde dehydrogenase (ALDH2), an enzyme very important to the dopamine (DA) metabolic pathway. DA undergoes monoamine oxidase-catalyzed oxidative deamination to 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is metabolized primarily to 3,4-dihydroxyphenylacetic acid (DOPAC) via ALDH2. The biotransformation of DOPAL is critical as previous studies have demonstrated this DA-derived aldehyde to be a reactive electrophile and toxic to dopaminergic cells. Therefore, 4HNE produced via oxidative stress may inhibit ALDH2-mediated oxidation of the endogenous neurotoxin DOPAL. To test this hypothesis, ALDH2 in various model systems was treated with 4HNE and activity toward DOPAL measured. Incubation of human recombinant ALDH2 with 4HNE (1.5-30 microM) yielded inhibition of activity toward DOPAL. Furthermore, ALDH2 in rat brain mitochondrial lysate as well as isolated rat brain mitochondria was also sensitive to the lipid peroxidation product at low micromolar, as evident by a decrease in the rate of DOPAL to DOPAC conversion measured using HPLC. Taken together, these data indicate that 4HNE at low micromolar inhibits mitochondrial biotransformation of DOPAL to DOPAC, and generation of the lipid peroxidation product may represent a mechanism yielding aberrant levels of DOPAL, thus linking oxidative stress to the uncontrolled production of an endogenous neurotoxin relevant to PD.

South African guideline on deep brain stimulation for Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is a common neurodegenerative disease, associated with severe impairment of quality of life. Although the motor aspects of the illness are typically successfully treated with medications acting on the dopaminergic system, a number of patients encounter progressive difficulties associated with their medical treatment. RECOMMENDATIONS: Carefully selected patients will benefit from deep brain stimulation (DBS) treatment for their PD. Selection requires dopamine challenge testing and neuropsychological testing for the presence of cognitive impairment. Careful follow-up and programming of the DBS system are mandatory, and a major reason for DBS failure is inadequate programming and management of medication. CONCLUSION: DBS is a useful component of standard therapy for PD and may reduce symptoms, improve quality of life, promote patient independence and reduce healthcare costs by reducing requirements for medicine.

Poly(glycoamidoamine) brush nanomaterials for systemic siRNA delivery in vivo.

Delivery is the key challenge for siRNA based therapeutics. Here, we report the development of new poly(glycoamidoamine) brush nanomaterials for efficient siRNA delivery. GluN4C10 polymer brush nanoparticles, a lead material, demonstrated significantly improved delivery efficiency for siRNA against factor VII (FVII) in mice compared to poly(glycoamidoamine) brush nanomaterials reported previously.

SSB protein controls RecBCD enzyme nuclease activity during unwinding: a new role for looped intermediates.

The RecBCD enzyme of Escherichia coli initiates homologous recombination by unwinding and simultaneously degrading DNA from a double-stranded DNA end. Single-stranded DNA loops are intermediates of this unwinding process. Here we show that SSB protein reduces the level of DNA degradation by RecBCD enzyme during unwinding, by binding to these ssDNA intermediates. Prior to interaction with the recombination hot spot chi, RecBCD enzyme has both 3'-->5' exonuclease and a weaker 5'-->3' exonuclease activity. We show that degradation of the 5'-terminal strand at the entry site is much more extensive in the absence of SSB protein. After interaction with chi, the level of 5'-->3' exonuclease activity is increased; as expected, degradation of the 5'-strand is also elevated in the absence of SSB protein. Furthermore, we show that, in the absence of SSB protein, the RecBCD enzyme is inhibited by the ssDNA products of unwinding; SSB protein alleviates this inhibition. These results provide insight into the organization of helicase and nuclease domains within the RecBCD enzyme, and also suggest a new level at which the nuclease activity of RecBCD enzyme is controlled. Hence, they offer new insight into the role of SSB protein in the initiation phase of recombination.

Physiological de novo thyroid hormone formation in primary culture of porcine thyroid follicles: adenosine 3',5'-monophosphate alone is sufficient for thyroid hormone formation.

We describe a method of culturing intact porcine thyroid follicles for physiological de novo thyroid hormone formation; the roles of cAMP and protein kinase-C in thyroid hormone formation were also studied. Thyroid follicles were obtained by digesting minced porcine thyroid tissue with 0.04% collagenase and cultured in Coon's Modified Ham's F-12 medium supplemented with 0.5% calf serum, 0.5 mU/ml TSH, other standard hormones, and 3 antibiotics (6H medium). On the fourth day of culture, 6000-8000 follicles/well were plated in 12-well culture dishes. On the sixth day, thyroid hormone formation was carried out by incubating thyroid follicles with 0.5 microM KI in the presence of 6H medium for 2 days in a 5% CO2-95% air incubator at 37 C. To examine the effects of cAMP and protein kinase-C on de novo thyroid hormone formation, follicles were incubated with KI in the presence of 1-2.5 mM (Bu)2cAMP, 10 microM forskolin, 2 microM prostaglandin E2 (PGE2), or 0.5-1 microM 12-O-tetradecanoylphorbol-13-acetate in TSH-free medium for 2 days. The amount of newly formed thyroid hormone was measured by RIA of T3 content in the Pronase digest of thyroid follicular cells. Thyroid follicles cultured in 6H medium had normal polarity of the membrane, determined by electron microscope, and thyroid cAMP was responsive to the alteration of TSH. In this culture system cAMP alone was sufficient to form thyroid hormone. 12-O-Tetradecanoylphorbol-13-acetate, a protein kinase-C stimulator, disrupted thyroid follicles and inhibited cAMP-mediated thyroid hormone formation. The integrity of follicular structure was also required for thyroid hormone formation in this culture system. This study introduces perhaps the most physiological culture system for de novo thyroid hormone formation. Our data provide direct evidence that thyroid hormone formation is linked to cAMP and that the protein kinase-C system acts as an inhibitor of thyroid hormone formation.

Neighborhood screening in communities throughout the nation for children with elevated blood lead levels.

From the spring of 1971 to September 1973, neighborhood surveys were conducted in 58 communities throughout the nation to determine whether children with confirmed elevated blood lead levels could be identified. Another purpose of these screenings was to assist communities in identifying children with elevated blood lead levels and thereby demonstrate to community officials that such children do exist in communities screened. The children screened were not a random sample.In those communities where the initial elevated blood levels were confirmed all but seven had one or more children requiring followup and/or treatment. Of those children screened, black children had an elevated rate about three times as great as nonblack children. With few exceptions, the homes in the neighborhoods had at least one interior surface with sufficient quantities of lead paint to be dangerous if the paint were ingested.

Environmental endocrine disruption: an effects assessment and analysis.

This report is an overview of the current state of the science relative to environmental endocrine disruption in humans, laboratory testing, and wildlife species. Background information is presented on the field of endocrinology, the nature of hormones, and potential sites for endocrine disruption, with specific examples of chemicals affecting these sites. An attempt is made to present objectively the issue of endocrine disruption, consider working hypotheses, offer opposing viewpoints, analyze the available information, and provide a reasonable assessment of the problem. Emphasis is placed on disruption of central nervous system--pituitary integration of hormonal and sexual behavioral activity, female and male reproductive system development and function, and thyroid function. In addition, the potential role of environmental endocrine disruption in the induction of breast, testicular, and prostate cancers, as well as endometriosis, is evaluated. The interrelationship of the endocrine and immune system is documented. With respect to endocrine-related ecological effects, specific case examples from the peer-reviewed literature of marine invertebrates and representatives of the five classes of vertebrates are presented and discussed. The report identifies some data gaps in our understanding of the environmental endocrine disruption issue and recommends a few research needs. Finally, the report states the U.S. Environmental Protection Agency Science Policy Council's interim position on endocrine disruption and lists some of the ongoing activities to deal with this matter.

Benign gestational trophoblastic disease metastatic to pleura: unusual cause of hemothorax.

A unique case of hemothorax caused by proven pleural involvement with benign gestational trophoblastic disease and anticoagulation is presented. The pulmonary manifestations of gestational trophoblastic disease are reviewed. It is stressed that these may be associated with histologically benign as well as frankly malignant disease, and that the clinician must be alert for them in managing all patients with known or suspected gestational trophoblastic disease.

The effect of immunizing female rats with modified rat pituitary extract.

Immune reactions to a number of hormones have been induced, but information is lacking on the feasibility of inducing immune reactions to homologous gonadotropins. Female rats immunized with diazotized and tyrosylated rat pituitary extract containing gonadotropic activity and emulsified in complete Freund's adjuvant expressed various reproductive disturbances such as increased cycle length (7.0 days), increased number of sterile matings, reduced implantation in animals becoming pregnant, and reduced ability to carry fetuses to term. These effects were not exhibited by rats immunized similarly with diazotized or tyrosylated rat pituitary extract containing no detectable gonadotropic activity. Rats not becoming pregnant had a significantly higher antibody level to rat luteinizing hormone than did rats becoming pregnant. No significant elevation of rat follicle-stimulating hormone antibodies was noted. It is concluded that auto-immune reactions to gonadotropins can be induced and that very low levels of antibodies have a significant effect on reproduction.

Electron microscope study of the association between hypothalamic blood vessels and oxytocin-like immunoreactive neurons.

An association between oxytocin-like immunoreactive neurons and hypothalamic blood vessels has been observed with the light microscope. Recently, it has been demonstrated that oxytocin stimulates vascular smooth muscle contraction in vitro. A hypothesis has thus been proposed that oxytocin may play a role in modulating blood flow in certain brain regions. In a study on the golden-mantled ground squirrel (Spermophilus lateralis) we noted the association at the light microscope level between oxytocin-like immunoreactive neurons and blood vessels in preoptic and paraventricular nuclei of the hypothalamus. To determine if these neurons were associated with hypothalamic capillaries, transverse 30 micron immunostained hypothalamic sections were prepared for thin sectioning and observation by transmission electron microscopy. Oxytocin-like immunoreactive neurons were observed to lie within 77 nm of the edge of the lumen of capillary blood vessels. One neuronal cell body was observed approximately 380 nm from the edge of a capillary lumen and what appears to be an output region of a neuron was observed to terminate on the basement membrane of a capillary blood vessel.

Three medical schools' responses to the HIV/AIDS epidemic and the effect on students' knowledge and attitudes.

PURPOSE: To assess the relative importance of factors influentail by the prevalence of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), such as didactic and clinical training, and the number of HIV-infected individuals known personally, on students' HIV-related knowledge and attitudes. METHOD: A survey was undertaken of the classes of 1991 and 1994 at the University of Colorado School of Medicine, the University of New Mexico School of Medicine, and the University of South Dakota School of Medicine. The questionnaire contained 40 knowledge questions, 20 attitude questions, and demographic questions. The students reported estimates of HIV-related didactic hours and clinical encounters experienced during their training, as well as the number of HIV-infected individuals known personally. Data analysis employed two-way analysis of variance (ANOVA) and Pearson correlation coefficients. RESULTS: In 1991 the response rates were 73% from Colorado, 54% from New Mexico, and 50% from South Dakota; in 1994 the rates were 80%, 63%, and 60%, respectively. Training programs were similar between schools and over time, varying only in the amounts of didactic information offered. The 1994 students scored significantly better than did 1991 students on knowledge, overall attitude, fear of infection, and willingness to treat HIV-infected patients; these variables were significantly correlated with the numbers of HIV-infected individuals known personally by the students. Didactic training hours were not significantly correlated with any study variable, and clinical experiences were correlated only with increased knowledge. CONCLUSION: Differences in HIV/AIDS prevalences did not affect the schools' training programs, but indirectly affected the students' knowledge and attitudes, which were related to the numbers of HIV-infected individuals known personally by the students. The authors recommend that medical schools increase students' opportunities for meaningful personal contact with HIV-infected individuals.

A clinical assessment of the effects of 10% carbamide peroxide gel on human pulp tissue.

Bleaching vital teeth with 10% carbamide peroxide gel is a routine procedure in which there has been no evidence of associated permanent pulpal damage. Synthesis of the enzyme heme oxygenase-1 (HO-1) is increased after exposure of eukaryotic cells to conditions of oxidative stress (including H2O2) as a defense against the damaging effects of free radicals. Dental pulps were evaluated for HO-1 (aka Heat Shock Protein 32) presence in teeth treated with 10% carbamide peroxide. Seventeen intact first premolars scheduled for orthodontic extraction were bleached for 4 h immediately preceding extraction. Fourteen additional premolars from the same individuals were not bleached. All 31 teeth were extracted, fixed, demineralized, frozen, sectioned, and immunostained with anti-HO-1 antibody using a standard ABC protocol. There was no significant difference in the presence of HO-1 between total bleached versus total unbleached teeth using the Fisher's Exact Test (p < or = 0.05). However, the histological findings could be interpreted to suggest that coronal odontoblasts and endothelial cells in the underlying pulp proper may have the potential to respond to oxidative stress by increasing the synthesis of HO-1 (HSP32). This could represent a component of an initial defensive response by specific cells in strategic locations in the pulp that precedes classical inflammatory pathways.