Deep brain stimulation of the subthalamic nucleus: effectiveness in advanced Parkinson's disease patients previously reliant on apomorphine

OBJECTIVES

To assess the efficacy of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with advanced Parkinson's disease previously reliant on apomorphine as their main antiparkinsonian medication.

METHODS

Seven patients with motor fluctuations despite optimal medical treatment given as predominantly apomorphine infusion (n=6), or intermittent apomorphine injections (n=1) underwent bilateral STN DBS using frameless stereotactic surgery. Standard assessments of parkinsonism and motor fluctuations, using Unified Parkinson's Disease Rating Scale (UPDRS) were performed before and six months after surgery. Assessments were performed both on and off medication, and postoperative with the stimulators switched on and off.

RESULTS

Bilateral STN DBS improved motor scores (UPDRS III) by 61% when off medication (p<0.05). Clinical fluctuations (UPDRS IV items 36-39) were reduced by 46.2% (p<0.05). Total daily apomorphine dose was reduced by 68.9% (p<0.05) and apomorphine infusion via a pump was no longer required in four patients. There were no operative complications. Two patients required treatment for hallucinations postoperatively but there was no significant change in mini-mental state examination.

CONCLUSIONS

In patients with advanced Parkinson's disease, previously reliant on apomorphine, bilateral STN DBS is an effective treatment to reduce motor fluctuations and enable a reduction in apomorphine use.

The effects of assisted reproduction on the trends and zygosity of multiple births in England and Wales 1974-99

Assisted reproductive techniques have led to an increase in the proportion of maternities that are multiple. Though predominantly dizygotic, they are at greater risk of monozygotic division than those spontaneously conceived. England and Wales data 1974-99 on stillbirths and livebirths were analysed for 4 periods: 1974-80 (pre-assisted reproduction; 1982-8; 1989-91 (pre-redefinition of stillbirth); 1993-9 (post-redefinition of stillbirth). For twin data, Weinberg's rule was applied to estimate the proportions that were mono- (MZ) and dizygotic (DZ). Compared with the period before assisted reproduction, the most recent period shows an increase in twin maternities of 3.81 per 1,000 comprised of 3.22 (95% CI 3.10 to 3.33; p < 0.0001) DZ and 0.60 (95% CI 0.51 to 0.68; p < 0.0001) MZ twins. It is estimated that 15.7% of assisted reproduction twins are MZ. Higher order multiple births showed an increase of 3.06 (95% CI 2.85 to 3.29; p < 0.0001) per 10,000 maternities. Stillbirth rates in MZ twins are of the same order of magnitude as those in higher order multiple births but higher than those in DZ twins. The improvement in stillbirth rates over the 26 year study period is of the same order magnitude in singletons, DZ and MZ twins and higher order multiples. Assisted reproduction has led to a significant increase in the proportion of MZ twins. These are at high risk of fetal death and this needs to be considered when local stillbirth and perinatal mortality rates are used in auditing obstetric services.

Convulsive syncope in young adults: think of a cardiac cause

Convulsive syncope is often misdiagnosed as epilepsy because of its similarity in clinical presentation. We present the case of a patient who had several such episodes before a definitive diagnosis was made. The diagnosis of prolonged sinus arrest was finally made with the valuable assistance of cardiac monitoring during a witnessed episode of convulsive syncope. Appropriate therapy was promptly introduced, i.e. temporary then permanent cardiac pacing. It is possible that any further delay in reaching the correct diagnosis and delivering appropriate treatment might have carried a significant risk of morbidity and mortality. Continuous electrocardiographic monitoring performed at an early stage is therefore crucial in the initial assessment of a young adult presenting with convulsive syncope, as a significant proportion may have a cardiovascular aetiology, particularly arrhythmias, for their syncopal episodes.

Emotional change processes in music-assisted reframing

Affective processes are critical to understanding and promoting lasting therapeutic change. Using a sample of 40 anxious adults, the researchers examined the use of music to increase affective modification and emotional restructuring in a cognitive reframing intervention. Subjects were assigned to either a typical reframing intervention or a music-assisted reframing intervention. Using the State-Trait Anxiety Inventory, Subjective Units of Distress Scale, Depression Adjective Checklist, and a Think-Aloud measure, the groups were compared on basis of anxiety-reduction, affective modification, and imagery vividness. Results indicate that the music-assisted reframing intervention was more efficacious than the typical reframing intervention in reducing anxiety, modifying affect, and promoting imagery-vividness.

Investigation of spatial clustering from individually matched case-control studies

The paper demonstrates how existing theory to assess spatial clustering based on second-moment properties of a labelled point process can be adapted to matched case-control studies. The null hypothesis that cases are a random sample from the superposition of cases and controls is replaced by the hypothesis that each case is a random sample from the set consisting of itself and its k matched controls. We compare the proposed test with other tests of spatial clustering, and describe an application to data on childhood diabetes in Yorkshire, England.

Local transgenic expression of granulocyte macrophage-colony stimulating factor initiates autoimmunity

Mechanisms leading to breakdown of immunological tolerance and initiation of autoimmunity are poorly understood. Experimental autoimmune gastritis is a paradigm of organ-specific autoimmunity arising from a pathogenic autoimmune response to gastric H/K ATPase. The gastritis is accompanied by autoantibodies to the gastric H/K ATPase. The best characterized model of experimental autoimmune gastritis requires neonatal thymectomy. This procedure disrupts the immune repertoire, limiting its usefulness in understanding how autoimmunity arises in animals with intact immune systems. Here we tested whether local production of GM-CSF, a pro-inflammatory cytokine, is sufficient to break tolerance and initiate autoimmunity. We generated transgenic mice expressing GM-CSF in the stomach. These transgenic mice spontaneously developed gastritis with an incidence of about 80% after six backcrosses to gastritis-susceptible BALBc/CrSlc mice. The gastritis is accompanied by mucosal hypertrophy, enlargement of draining lymph nodes and autoantibodies to gastric H/K ATPase. An infiltrate of dendritic cells and macrophages preceded CD4 T cells into the gastric mucosa. T cells from draining lymph nodes specifically proliferated to the gastric H/K ATPase. CD4 but not CD8 T cells transferred gastritis to nude mouse recipients. CD4(+) CD25(+) T cells from the spleen retained anergic suppressive properties that were reversed by IL-2. We conclude that local expression of GM-CSF is sufficient to break tolerance and initiate autoimmunity mediated by CD4 T cells. This new mouse model should be useful for studies of organ-specific autoimmunity.

Brain chirps: spectrographic signatures of epileptic seizures

OBJECTIVE

A chirp is a brief signal within which the frequency content changes rapidly. Spectrographic chirps are found in signals produced from many biological and physical phenomena. In radar and sonar engineering, signals with chirps are used to localize direction and range to the signal source. Although characteristic frequency changes during epileptic seizures have long been observed, the correlation with chirps and chirp technology seems never to have been made.

METHODS

We analyzed 19404 s (1870 s of which were from 43 seizures) of intracranially (subdural and depth electrode) recorded digital EEG from 6 patients for the presence of spectral chirps. Matched filters were constructed from methods in routine use in non-medical signal processing applications.

RESULTS

We found that chirps are very sensitive detectors of seizures (83%), and highly specific as markers (no false positive detections). The feasibility of using spectral chirps as matched filters was demonstrated.

CONCLUSIONS

Chirps are highly specific and sensitive spectrographic signatures of epileptic seizure activity. In addition, chirps may serve as templates for matched filter design to detect seizures, and as such, can demonstrate localization and propagation of seizures from an epileptic focus.

Control of acidic drain-water-breeding mosquitoes in New South Wales, Australia, by installing controlled leakage holes in tidal flap gates

Effects on mosquito breeding, acidity, and fish presence were assessed after installation of a small tidal leakage port into an acidic drain's tidal exclusion flap gate. Before gate modification the drain water had pH values as low as 2.7. These water conditions were toxic to fish and continually held mosquito larvae. At 4 wk after gate modification, water pH had risen to 6.0, at least 3 fish species inhabited the drain, and mosquito larval numbers had been reduced by 99.98%.

Protein profiles in various epididymal segments of normal and castrated rats

AIM

Epididymal proteins are known to play an important role in the maturation of spermatozoa. We ought to determine if there are regional differences in androgen-dependent epididymal proteins.

METHODS

A group of adult rats was castrated and epididymides were removed three days following castration. The epididymides were dissected into caput, corpus and cauda segments, homogenized, and proteins were fractionated by anion exchange HPLC. Proteins in selected fractions were resolved by SDS-PAGE and visualized by silver staining.

RESULTS

It was observed that the levels of multiple proteins drastically reduced in the various regions of epididymis of the orchiectomized rats.

CONCLUSION

The epididymal proteins appear to be useful markers to study androgenic action in the epididymis.

Use of continuous positive airway pressure (CPAP) in the critically ill--physiological principles

CPAP therapy helps improve oxygenation in patients who are awake and able to maintain a good respiratory drive. In many cases this means that intubation and ventilation can be avoided. The main goals of CPAP are to minimise alveolar collapse, improve compliance, decrease work of breathing and improve ventilation/perfusion matching. These effects work together to improve arterial oxygenation. A clear, concise and straightforward discussion of CPAP is difficult to find in the existing literature. As CPAP has developed into a common therapy for patients with respiratory failure, it is essential that nurses using this therapy are familiar with the equipment and the physiological effects it produces. Assessment and management of the patient receiving CPAP therapy are also important. This paper will address the physiological principles of CPAP therapy so that nurses working with critically ill patients receiving CPAP therapy understand the system and are accurate and astute in their respiratory assessment, in order to provide optimum care.

Messenger RNA editing of the human serotonin 5-HT2C receptor

RNA encoding the rat serotonin 5-HT2C receptor undergoes editing whereby one to four adenosines are converted to inosines. This conversion can change up to three codons out of a stretch of five in the second intracellular loop of the receptor. RNA editing of the rat 5-HT2C receptor that changes all three codons was shown previously to alter intracellular signaling by 5-HT without changing its receptor-binding affinity. We analyzed 5-HT2C receptor editing in human brain and hypothalamic RNA samples and confirmed that all four adenosine editing sites observed in rat were also present in human samples. Additionally, we identified a novel editing site in the middle edited codon that extends the repertoire of 5-HT2C receptors by six additional protein isoforms. We observed that editing reduces both the binding affinity and functional potency of agonists for recombinant human 5-HT2C receptor isoforms. This effect on binding affinity was proportional to the agonist's intrinsic activity, with full agonists most affected, and antagonists showing no effect. These data suggest that RNA editing may alter coupling energetics within the ternary complex, thereby altering agonist binding affinities, G protein coupling, and functional responses. RNA editing may thus provide a novel mechanism for regulating 5-HT synaptic signaling and plasticity.

Extensive junctional diversity in Ig light chain genes from early B cell progenitors of mu MT mice

Nontemplated (N) nucleotide additions contribute significantly to the junctional diversity of all Ag receptor chains in adult mice except Ig light (L) chains, primarily because terminal deoxynucleotidyl transferase (TdT) expression is turned off at the time of their rearrangement in pre-B cells. However, because some Ig L chain gene rearrangements are detectable earlier during B cell ontogeny when TdT expression is thought to be maximal, we have examined the junctional processing of kappa- and lambda-chain genes of CD45(B220)+CD43+ pro-B cells from mu MT mice. We found that both kappa and lambda coding junctions formed in these B cell precursors were extensively diversified with N-region additions. Together, these findings demonstrate that Ig L chain genes are equally accessible to TdT in pro-B cells as Ig heavy chain genes. Surprisingly, however, the two L chain isotypes differed in the pattern of N addition, which was more prevalent at the lambda-chain locus. We observed the same diversity pattern in pre-B cells from TdT-transgenic mice. These results suggest that some aspects of TdT processing could be influenced by factors intrinsic to the sequence of Ig genes and/or the process of V(D)J recombination itself.

Fibulin-2 exhibits high degree of variability, but no structural changes concordant with abdominal aortic aneurysms

We used conformation sensitive gel electrophoresis and direct sequencing of PCR products to screen for mutations in the cDNA for fibulin-2, an extracellular matrix protein, from 11 patients with abdominal aortic aneurysms and two controls. When compared with the published reference sequence, a total of 14 single-base sequence variations were detected. Seven of the changes were neutral in that they did not result in an amino acid substitution. There were five missense changes at sites not conserved between human and mouse, and two missense changes at sites conserved between human and mouse. All but two of the sequence variants studied were also present in an additional set of 102 control alleles analyzed. One of these two changes was a missense mutation, but it did not segregate with abdominal aortic aneurysms in the family, whilst the other change was neutral. In conclusion, fibulin-2 has a large number of sequence variations in comparison with our previous analyses of type III collagen, and these variations will be useful in association studies. There was an excellent overall agreement between direct sequencing of PCR-products and conformation sensitive gel electrophoresis.