Subthalamic nucleus stimulation in Parkinson's disease: clinical evaluation of 18 patients

The aim of the present study was to assess the efficacy and safety of chronic subthalamic nucleus deep-brain stimulation (STN-DBS) in patients with Parkinson's disease (PD). 18 consecutive severely affected PD patients were included (mean age, SD: 56.9+/-6 years; mean disease duration: 13.5+/-4.4 years). All the patients were evaluated clinically before and 6 months after the surgical procedure using the Unified Parkinson's Disease Rating Scale (UPDRS). Additionally, a 12 months follow-up was available in 14 patients. The target coordinates were determined by ventriculography under stereotactic conditions, followed by electrophysiology and intraoperative stimulation. After surgery, continuous monopolar stimulation was applied bilaterally in 17 patients at 2.9+/-0.4 V through 1 (n = 31) or 2 contacts (n = 3). One patient had bilateral bipolar stimulation. The mean frequency of stimulation was 140+/-16 Hz and pulse width 68+/-13 micros. Off medication, the UPDRS part III score (max = 108) was reduced by 55 % during on stimulation (score before surgery: 44.9+/-13.4 vs at 6 months: 20.2+/-10; p < 0.001). In the on medication state, no difference was noted between the preoperative and the postoperative off stimulation conditions (scores were respectively: 17.9+/-9.2 and 23+/-12.6). The severity of motor fluctuations and dyskinesias assessed by UPDRS IV was reduced by 76 % at 6 months (scores were respectively: 10.3+/-3 and 2.5+/-3; p < 0.001). Off medication, the UPDRS II or ADL score was reduced by 52.8 % during on stimulation (26.9+/-6.5 preop versus 12.7+/-7 at 6 months). The daily dose of antiparkinsonian treatment was diminished by 65.5 % (levodopa equivalent dose -- mg/D -- was 1045 +/- 435 before surgery and 360 +/- 377 at 6 months; p < 0.01). These results remained stable at 12 months for the 14 patients studied. Side effects comprised lower limb phlebitis (n = 2), pulmonary embolism (n = 1), depression (n = 6), dysarthria and freezing (n = 1), sialorrhea and drooling (n = 1), postural imbalance (n = 1), transient paresthesias and dyskinesias. This study confirms the great value of subthalamic nucleus stimulation in the treatment of intractable PD. Some adverse events such as depression may be taken into account in the inclusion criteria and also in the post-operative outcome.

Neurosurgical management of neuropathic pain

Neuropathic pain is a very difficult problem with which the neurosurgeon frequently must deal. The neurosurgical methods to be considered are: (1) modulative, by using neurostimulation or implanted drug delivery systems, and (2) ablative, by making selective therapeutic lesions in well-defined and identified targets proven to sustain pain mechanisms (especially DREZotomy).

Translocation portals for the substrates and products of a viral transcription complex: the bluetongue virus core

The bluetongue virus core is a molecular machine that simultaneously and repeatedly transcribes mRNA from 10 segments of viral double-stranded RNA, packaged in a liquid crystalline array. To determine how the logistical problems of transcription within a sealed shell are solved, core crystals were soaked with various ligands and analysed by X-ray crystallography. Mg(2+) ions produce a slight expansion of the capsid around the 5-fold axes. Oligonucleotide soaks demonstrate that the 5-fold pore, opened up by this expansion, is the exit site for mRNA, whilst nucleotide soaks pinpoint a separate binding site that appears to be a selective channel for the entry and exit of substrates and by-products. Finally, nucleotides also bind to the outer core layer, providing a substrate sink.

Induction of immune response in BALB/c mice with a DNA vaccine encoding bacterioferritin or P39 of Brucella spp

In this study, we evaluated the ability of DNA vaccines encoding the bacterioferritin (BFR) or P39 proteins of Brucella spp. to induce cellular and humoral immune responses and to protect BALB/c mice against a challenge with B. abortus 544. We constructed eukaryotic expression vectors called pCIBFR and pCIP39, encoding BFR or P39 antigens, respectively, and we verified that these proteins were produced after transfection of COS-7 cells. PCIBFR or pCIP39 was injected intramuscularly three times, at 3-week intervals. pCIP39 induced higher antibody responses than did the DNA vector encoding BFR. Both vectors elicited a T-cell-proliferative response and also induced a strong gamma interferon production upon restimulation with either the specific antigens or Brucella extract. In this report, we also demonstrate that animals immunized with these plasmids elicited a strong and long-lived memory immune response which persisted at least 3 months after the third vaccination. Furthermore, pCIBFR and pCIP39 induced a typical T-helper 1-dominated immune response in mice, as determined by cytokine or immunoglobulin G isotype analysis. The pCIP39 delivered by intramuscular injection (but not the pCIBFR or control vectors) induced a moderate protection in BALB/c mice challenged with B. abortus 544 compared to that observed in positive control mice vaccinated with S19.

Protection of BALB/c mice against Brucella abortus 544 challenge by vaccination with bacterioferritin or P39 recombinant proteins with CpG oligodeoxynucleotides as adjuvant

The P39 and the bacterioferrin (BFR) antigens of Brucella melitensis 16M were previously identified as T dominant antigens able to induce both delayed-type hypersensivity in sensitized guinea pigs and in vitro gamma interferon (IFN-gamma) production by peripheral blood mononuclear cells from infected cattle. Here, we analyzed the potential for these antigens to function as a subunitary vaccine against Brucella abortus infection in BALB/c mice, and we characterized the humoral and cellular immune responses induced. Mice were injected with each of the recombinant proteins alone or adjuvanted with either CpG oligodeoxynucleotides (CpG ODN) or non-CpG ODN. Mice immunized with the recombinant antigens with CpG ODN were the only group demonstrating both significant IFN-gamma production and T-cell proliferation in response to either Brucella extract or to the respective antigen. The same conclusion holds true for the antibody response, which was only demonstrated in mice immunized with recombinant antigens mixed with CpG ODN. The antibody titers (both immunoglobulin G1 [IgG1] and IgG2a) induced by P39 immunization were higher than the titers induced by BFR (only IgG2a). Using a B. abortus 544 challenge, the level of protection was analyzed and compared to the protection conferred by one immunization with the vaccine strain B19. Immunization with P39 and CpG ODN gave a level of protection comparable to the one conferred by B19 at 4 weeks postchallenge, and the mice were still significantly protected at 8 weeks postchallenge, although to a lesser extent than the B19-vaccinated group. Intriguingly, no protection was detected after BFR vaccination. All other groups did not demonstrate any protection.

Neurosurgery for spasticity

Spasticity is usually a useful substitute for deficiency of motor strength. However not infrequently, it may become harmful leading to an aggravation of motor disability. When excessive spasticity is not sufficiently controlled by physical therapy and pharmacological treatment, patients can have recourse to neurosurgery: neurostimulation, intrathecal baclofen or selective ablative procedures. Because excessive hypertonia has to be reduced without suppression of the useful muscular tone or impairment in the residual motor and sensory functions, neuroablative procedures must be as selective as possible. These selective lesions can be performed at the level of peripheral nerves, spinal roots, spinal cord, or the dorsal root entry zone (DREZ lesions).

Composition and mass of the bacteriophage phi29 prohead and virion

The protein composition of the Bacillus subtilis bacteriophage phi29 prohead and virion was determined by combustion of gel bands of (3)H-labeled proteins. Copy numbers of individual proteins were calculated relative to the 12 copies of the head-tail connector protein. The mean numbers of copies of the major capsid protein in the prohead and virion were 241 and 218, respectively, approaching the 235 copies determined previously by cryoelectron microscopy. The mean numbers of copies of the dimeric head fiber on the prohead and virion were 24 and 31, respectively, demonstrating partial occupancy of the 55 fiber binding sites. Measured copies of neck and tail proteins in the virion included 11 of the lower collar, 58 of the appendage, and 9 of the tail; if the true copies of these proteins are 12, 60, and 9, respectively, the entire neck and tail of phi29 has quasi-sixfold symmetry. The mass of the fiberless prohead with pRNA was about 14.2 MDa, and the mass of the prohead determined by scanning transmission electron microscopy was consistent with the biochemical data. The mass of the fiberless virion containing the 12.8-MDa DNA genome was about 30.4 MDa. A full complement of dimeric fibers on the prohead or virion would increase the mass of the particle by about 3.2 MDa. The data complement studies relating the structure of phi29 components to dynamic functions in morphogenesis and infection.

Identification of Brucella spp. genes involved in intracellular trafficking

After uptake by host cells, the pathogen Brucella transits through early endosomes, evades phago-lysosome fusion and replicates in a compartment associated with the endoplasmic reticulum (ER). The molecular mechanisms underlying these processes are still poorly understood. To identify new bacterial factors involved in these processes, a library of 1800 Brucella melitensis 16M mini-Tn5catkm mutants was screened for intracellular survival and multiplication in HeLa cells and J774A.1 macrophages. Thirteen mutants were identified as defective for their intracellular survival in both cell types. In 12 of them, the transposon had inserted in the virB operon, which encodes a type IV-related secretion system. The preponderance of virB mutants demonstrates the importance of this secretion apparatus in the intracellular multiplication of B. melitensis. We also examined the intracellular fate of three virB mutants (virB2, virB4 and virB9) in HeLa cells by immunofluorescence. The three VirB proteins are not necessary for penetration and the inhibition of phago-lysosomal fusion within non-professional phagocytes. Rather, the virB mutants are unable to reach the replicative niche and reside in a membrane-bound vacuole expressing the late endosomal marker, LAMP1, and the sec61beta protein from the ER membrane, proteins that are present in autophagic vesicles originating from the ER.

Short amputation stump lengthening with the Ilizarov method: risks versus benefits

The authors point out the indications for lengthening of short amputation stumps. Referring to their own experience they discuss the problems and pitfalls related to this surgical procedure. Sufficient soft tissue coverage is the most important factor for a good outcome whereas limitation of adjacent joint function may have a detrimental effect on the clinical result.

Microsurgical DREZotomy for pain due to spinal cord and/or cauda equina injuries: long-term results in a series of 44 patients

According to the literature estimations, 10-25% of patients with spinal cord and cauda equina injuries eventually develop refractory pain. Due to the fact that most classical neurosurgical methods are considered of little or no efficacy in controlling this type of pain, the authors had recourse to microsurgery in the dorsal root entry zone (DREZ). This article reports on the long-term results of the microsurgical approach to the dorsal root entry zone (DREZotomy) in a series of 44 patients suffering from unbearable neuropathic pain secondary to spine injury. The follow-up ranged from 1 to 20 years (6 years on average). The series includes 25 cases with conus medullaris, 12 with thoracic cord, four with cauda equina and three with cervical cord injuries. Surgery was performed in 37 cases at the pathological spinal cord levels that corresponded to the territory of the so-called 'segmental pain', and in seven cases, on the spinal cord levels below the lesion for 'infralesional pain' syndromes. The post-operative analgesic effect was considered to be 'good' when a patient's estimation of pain relief exceeded 75%, 'fair' if pain was reduced by 25-75%, and 'poor' when the residual pain was more than 75% of preoperative estimations. Immediate pain relief was obtained in 70% of patients and was long-lasting in 60% of the total series. The results varied essentially according to the distribution of pain. Good long-term results were obtained in 68% of the patients who had a segmental pain distribution, compared with 0% in patients with predominant infralesional pain. Regarding pain characteristics, a good result was obtained in 88% of the cases with predominantly paroxysmal pain, compared with 26% with continuous pain. There were no perioperative mortalities. Morbidity included cerebrospinal fluid leak (three patients), wound infection (two patients), subcutaneous hematoma (one patient) and bacteremia (in one patient). The above data justify the inclusion of DREZ-lesioning surgery in the neurosurgical armamentarium for treating 'segmental' pain due to spinal cord injuries.

[Interreg II--European regional study of chronic respiratory tract diseases in children in the Germany-Netherlands border zone]

AIM OF THE STUDY

In Westelijke Mijnstreek (WM), Midden-Limburg (ML), both The Netherlands, and Kreis Heinsberg (HS), Germany, the relationship between quality of the indoor environment and respiratory symptoms in children was studied, finally resulting in proposals for prevention of respiratory symptoms in the three regions. This paper presents the results of the first part of the study, investigating prevalences of respiratory complaints.

METHODS AND RESULTS

A brief questionnaire was used to document prevalences of respiratory complaints, physicians diagnoses and treatment in about 7,000 children 5-6 resp. 7-8 years of age from HS, ML and WM, in 1995 and 1997. Prevalences of respiratory symptoms differed slightly between the regions, but there were differences in physician-diagnosed asthma and bronchitis and treatment of the children.

PERSPECTIVES

The brief questionnaire is a useful instrument to get an overview on respiratory symptoms. Since 1995, it is used by several German Municipal Health Services for Public Health Reports.

Review and evaluation of anatomy sites on the Internet (updated 1999)

In a preceding study, we had reviewed and evaluated the anatomy sites available on the Internet. The evolution of the available sites, the disappearance of certain sites and the appearance of new sites led us to update this list. In addition, the German-speaking sites were included in the study, which previously included only the Anglophone and French-speaking sites. Forty-eight sites were indexed and their addresses are available on the site of the Laboratory of Anatomy of the Faculty of Medicine Lyon-Nord (http://rockefeller.univ-lyon1.fr/Anatomie-Lyon- Nord). Compared to the scores allotted in 1998, we noted in 1999 a significant increase (p = 0.03) in the total score (12.13 +/- 2.98 vs. 11.23 +/- 2.28/20), which shows that the quality of the anatomic sites available on the Internet has improved.

Radiologic anatomy of the spinal dorsal horn at the cervical level (anatomic-MRI correlations)

The spinal dorsal horn is known for its important functional role in the field of transmission and modulation of sensory afferents. Because of this, the dorsal horn represents a target for numerous analgesic and antispastic procedures. Thus, it would be interesting to develop imaging dedicated to this spinal structure. The purpose of this study was to investigate the radiologic anatomy of the cervical dorsal horn by magnetic resonance imaging (MRI) (1.5T). The first step consisted in the validation of the anatomic information provided by MRI on 5 human cadavers. A spin-echo sequence (T2, 2000/45) enabled the demonstration of good correlations between histologic sections and axial MRI slices performed at the corresponding cervical levels. The second step was the <<in vivo>> exploration of 20 subjects, aiming at the development of a gradient echo sequence (T2*) with a conventional MRI unit, compatible with a routine clinical examination. The dorsal horn was clearly identified in 77% of the axial slices performed (n = 300). The angle between the dorsal horn axis and the sagittal plane was measured as from 25.5 degrees at C2 to 40 degrees at C8 segments. The results of this anatomico-radiologic study of the cervical dorsal horn suggest that preoperative MRI could be useful to design the surgical approach to this structure, as performed during cervical microsurgical drezotomy (DREZ = dorsal root entry zone) for the treatment of selected cases of chronic pain or disabling spasticity in the upper limbs.

Microdialysis study of amino acid neurotransmitters in the spinal dorsal horn of patients undergoing microsurgical dorsal root entry zone lesioning. Technical note

The aim of this study was to develop, for the first time in the human spinal dorsal horn (DH), an in vivo method for the study of amino acids (AAs). A microdialysis technique was used to sample AAs in the extracellular fluid of the DH apex in eight patients in whom surgery in the dorsal root entry zone (DREZ) was performed. Before making microsurgical lesions, specific concentric-type microdialysis probes were implanted over a 60-minute period in the DREZ and directed to the DH apex (10 implantations). The AA concentrations in the dialysates were determined using high-performance liquid chromatography with fluorescence detection. The concentrations of excitatory AAs (glutamate and aspartate) and inhibitory AAs (gamma-aminobutyric acid and glycine) decreased and were stabilized by 45 minutes after probe implantation, whereas the levels of nonneurotransmitter AAs (alanine and threonine) were not stabilized at 60 minutes. The ability of the probe to track the changes of extracellular AAs was demonstrated. Neither intra- nor postoperative microdialysis-related complications were observed (with a follow up of 18 months). The present study demonstrates that microdialysis can be performed safely in the human DH during DREZ lesioning. Despite technical and analytical limitations related to the intraoperative conditions, this technique offers new possibilities for clinical research on neurotransmitters involved in some relevant pathological states, especially in chronic pain and spasticity.

[Surgery in the dorsal root entry zone for treatment of chronic pain]

Microsurgical drezotomy (MDT) consists of an incision and bipolar coagulations performed ventro-laterally in the Dorsal Root Entry Zone (DREZ) at the entrance of the rootlets into the dorso-lateral sulcus. The lesion is directed at 35 ventro-medially, and to 2-3 mm deep according to the pre-operative neurological status and the desired effects. MDT i) interrupts the small (nociceptive) fibres regrouped laterally and the large (myotatic) afferents which runs centrally, whilst sparing part of the large medial (lemniscal) fibres, ii) destroys the (excitatory) medial part of the Lissauer's tract, iii) and the cells of the dorsalmost layers of the dorsal horn, which can be the site of hyperactivity, as we were able to record in patients with deafferentation pain. Best indications are: i) well-localized cancer pain, such as Pancoast syndrome; ii) neuropathic pain due to: brachial plexus injuries; cauda equina and/or spinal cord lesions (especially for pain corresponding to segmental lesions); peripheral nerve injuries, amputation, herpes zoster - especially when the predominant component of pain is of the paroxysmal type and/or corresponds to provoked hyperalgesia/allodynia); iii) excess of spasticity, especially when associated with severe pain.

Identification and characterization of in vivo attenuated mutants of Brucella melitensis

Brucella melitensis 16M is a Gram-negative alpha2-proteobacterium responsible for abortion in goats and for Malta fever in humans. This facultative intracellular pathogen invades into and survives within both professional and non-professional phagocytes. Signature-tagged mutagenesis (STM) was used to identify genes required for the in vivo pathogenesis of Brucella. A library of transposon mutants was screened in a murine infection model. Out of 672 mutants screened, 20 were not recovered after a 5 day passage in BALB/c mice. The attenuation of 18 mutants was confirmed using an in vivo competition assay against the wild-type strain. The 18 mutants were characterized further for their ability to replicate in murine macrophages and in HeLa cells. The sequences disrupted by the transposon in the mutants have homology to genes coding for proteins of different functional classes: transport, amino acid and DNA metabolism, transcriptional regulation, peptidoglycan synthesis, a chaperone-like protein and proteins of unknown function. The mutants selected in this study provide new insights into the molecular basis of Brucella virulence.

Genetic organisation of the lipopolysaccharide O-antigen biosynthesis region of brucella melitensis 16M (wbk)

Brucella spp. are Gram-negative, facultative intracellular bacteria that cause a zoonotic world-wide disease. As in other Gram-negative bacteria, its S-LPS (smooth lipopolysaccharide) is a major determinant of virulence. The Brucella melitensis 16M LPS O-antigen is a homopolymer of 4-formamido-4,6, dideoxymannose. In this study, the previously cloned 14-kb wbk gene cluster was sequenced, and seven open reading frames (ORFs) as well as four insertion sequences were identified. Six of the seven ORFs are homologous to LPS biosynthesis genes from other organisms. The gmd, per and wbkC gene products are predicted to be involved in 4-formamido-4,6,dideoxymannose synthesis. By deletion experiments, we demonstrated that the putative formyltransferase WbkC is absolutely required for the O-side-chain production. The wbkA gene product is similar to several mannosyltransferases and is probably involved in the polymerisation of the B. melitensis O-side-chain. We also identified two genes (wzm and wzt) encoding proteins with high similarity to several two-component ABC (ATP-binding cassette) transporters. Their implication in O-antigen translocation across the inner membrane was confirmed by gene replacement. Finally, no function has been assigned to the wbkB gene either by homology search or functionally, because deletion of wbkB did not interfere with the O-antigen structure. The seven ORFs have a low G + C content, indicating that they might have been acquired by lateral transfer from a progenitor with more A + T rich DNA.

MRI assessment of the anatomy of optic radiations after temporal lobe epilepsy surgery

OBJECTIVE

The aim of this study was to determine the course of the temporal optic radiations.

MATERIAL AND METHODS

Eighteen patients were included in this prospective study. All of them underwent a temporal lobectomy for epilepsy, including the mesial temporal structures and a variable extent of lateral neocortex (from 2 to 7 cm behind the temporal tip). An MRI was performed 2 months postoperatively, allowing assessment of the extent of lateral resection. Postoperative visual fields were determined by automatic static perimetry (ASP).

RESULTS

(1) No patient complained of a disabling visual field deficit. (2) ASP, a highly sensitive technique, however, detected postoperative visual field deficits in 83% of patients, confined to the superior homonymous field contralateral to the resection. (3) A strong correlation was found between the presence of a visual field deficit and the extent of laterotemporal resection. (4) The smallest anteroposterior resection resulting in a field defect was limited to 20 mm from the temporal tip.

CONCLUSION

(1) This study confirms a strong correlation between postoperative visual field deficits and the extent of lateral neocortical temporal resection. (2) The anterior limit of Meyer's loop is likely to be located more rostrally than previously believed. (3) Despite this, lateral resection remains useful in some cases for seizure control.

Precentral cortex stimulation for the treatment of central neuropathic pain: results of a prospective study in a 20-patient series

The authors report a series of 23 patients with central neuropathic pain who were treated with the recently developed technique of precentral cortex stimulation (PCS). Of the 20 patients with a follow-up of more than 1 year (mean of 23 months) 25% had an excellent, 35% a good and 15% a fair relief of pain. In 25% the method failed. On the basis of these findings and the literature data (127 reported cases), the authors advocate PCS in patients with severe and medically refractory poststroke pain.

Amino acids in spinal dorsal horn of patients during surgery for neuropathic pain or spasticity

A specific microdialysis probe combined with high performance liquid chromatography analysis was used to compare the basal levels of extracellular amino acids (AAs) in the dorsal horn (DH) between two groups of patients undergoing spinal surgery for the treatment of peripheral neuropathic pain (n = 5) or disabling spasticity (n = 5). A stabilized concentration was reached in the dialysates 45 min after probe implantation for excitatory AAs (glutamate and aspartate) and inhibitory AAs (GABA and glycine). A significant increase in the ratios aspartate/GABA and aspartate/glycine was found in the group of patients suffering from neuropathic pain. This study shows the feasibility of a microdialysis investigation in the DH of patients during a neurosurgical operation and supports in humans the hypothesis of an imbalance between excitatory AAs and inhibitory AAs within the DH in neuropathic pain states, as suggested by previous animal studies.

Functional imaging and neurophysiological assessment of spinal and brain therapeutic modulation in humans

We summarize here our experience in the neurophysiological and neuroimaging assessment of spinal and brain neuromodulation for pain relief. Techniques reviewed include somatosensory evoked potentials (SEPs), nociceptive spinal (RIII) reflexes, and positron emission tomography (PET), which have been applied both to investigate the mechanisms and to optimize the application of neurostimulation procedures. SEPs are especially useful in the preoperative assessment of patients with neuropathic pain, as they allow the establishment of the functional state of the dorsal column system. Patients with strongly abnormal SEPs due to ganglionic or preganglionic pathology are not likely to benefit from spinal (SCS) or peripheral (TENS) neurostimulation, because ascending fibers disconnected from their soma will undergo rapid degeneration and not be excitable. In the postoperative period, nociceptive spinal reflexes yield objective data concerning the effects of neurostimulation on spinal circuitry. In our experience, the best clinical results are achieved in patients with preserved preoperative SEPs, in whom neurostimulation entails profound attenuation of nociceptive reflexes.PET-scan imaging techniques have recently been used to demonstrate changes in cerebral blood flow during new neuromodulation schemes such as motor cortex stimulation for pain control (MCS). PET studies highlight the thalamus as the key structure mediating functional MCS effects. Thalamic activation would trigger a cascade of synaptic events influencing activity in other pain-related structures including the anterior cingulate gyrus, insula, and upper brainstem. The combination of clinical electrophysiology and functional neuroimaging provides insight into the mechanisms of action of neuromodulation procedures, guides clinical decision, and contributes to optimize patient selection.