Where has all the botox gone? (How) will we ever learn… Using monoclonal antibodies to track botulinum toxin

Botulinum toxin (BTX) is an important therapeutic tool in the treatment of overactive skeletal and smooth muscles, as well as hypersecretory and painful disorders. Despite advances in our understanding of how BTX works, much remains to be elucidated, such as how BTX ameliorates pain, how it produces weakness remote from the site of injection and the fate of the heavy and light chain components of the BTX molecule following endocytosis into the presynaptic membrane. BTX, conjugated to radionuclides, allows investigators to track the molecule both in vitro and in vivo. However, altering the BTX molecule may cause structural changes or pharmacokinetic and pharmacodynamic alterations, and disrupt its normal action. We propose instead to bind the biomarkers (appropriate dyes, radionuclides or MRI contrast agents) to monoclonal antibodies directed against either heavy or light chain components of BTX, thus allowing administration of native (i.e. unaltered) BTX.

Botulinum toxin injections to reduce adiposity: Possibility, or fat chance?

Obese individuals often suffer from negative self-image. Many, even those with a normal body mass index, resort to pharmacotherapy (lipase inhibitors or appetite suppressants), mesotherapy and surgery (gastric volume reduction, liposuction or apronectomy) in a bid to remove excess adipose tissue. These treatments are associated with inherent morbidity and even mortality, and hence should not be undertaken lightly. The observation that denervation of adipose tissue results in lipoatrophy leads us to postulate that chemodenervation using botulinum toxin may achieve the same result, i.e. fat loss, and we explore the methods by which selective fat loss may be achieved. We concede that removal of subcutaneous fat does not, however, reduce the risks associated with the metabolic syndrome, as visceral (intra-abdominal) fat is not reduced by the removal of subcutaneous fat.

Strongyloides hyperinfection and hypogammaglobulinemia

We report strongyloides hyperinfection in two patients with generalized hypogammaglobulinemia from multiple myeloma and nephrotic syndrome, despite a significant strongyloides-specific immunoglobulin G (IgG) response. In contrast to reports on animals, where human IgG was shown to be a protective antibody, our observation suggests that in humans, immunity to the infective-stage larvae is not protective against the autoinfective larvae, which are the causative agents of strongyloides hyperinfection.

Acute transverse myelitis following dengue virus infection

The spinal cord is infrequently affected following dengue virus infection. We report a case of transverse myelitis that developed 2 weeks after acute dengue infection and review the literature to elucidate the pathogenesis of spinal cord involvement in dengue infection. We postulate that temporal factors may play a role in the different clinical manifestations, i.e. that acute parainfectious dengue infection presents with flaccid paralysis, whereas late-stage (postinfectious) dengue infection, presents with spastic weakness. Further studies need to be performed to elucidate the mechanisms of spinal neurological damage in dengue.

Adult-onset re-emergent stuttering as a presentation of Parkinson's disease

INTRODUCTION

The basal ganglia-thalamocortical motor circuits are postulated to play a key role in the aetiopathogenesis of stuttering. The main dysfunction is thought to be an impairment in the ability of the basal ganglia to produce timing cues for the initiation of the next motor segment of speech, explaining the association of acquired and re-emergent stuttering with diseases such as dystonia and Parkinson's disease.

CLINICAL PICTURE

We describe a 61-year-old man presenting with re-emergent stuttering and mild hypomimia, only to develop unilateral rest tremors, hypo- and bradykinesia, rigidity and gait difficulties one year later.

TREATMENT AND OUTCOME

His parkinsonism responded well to treatment with bromocriptine, but he continued to stutter.

DISCUSSION

This case illustrates the association between acquired or re-emergent stuttering and basal ganglia disorders, and highlights the need to assess such patients for an underlying aetiology.

Inhalational nickel carbonyl poisoning in waste processing workers

BACKGROUND

Nickel carbonyl is formed when carbon monoxide comes into contact with active nickel. The inhaled nickel carbonyl is rapidly absorbed and distributed mainly to the lungs, brain, adrenal glands, and kidneys. In severe cases, acute nickel carbonyl exposure has been reported to cause death.

DESIGN

Descriptive study.

PATIENTS

Seven young men presented with fever, chills, substernal pleuritic chest pain, and exertional dyspnea. Extensive microbiological and toxicological investigations (including blood, urine, and bronchial specimens) for known pathogens and occupational toxins were performed. The clinical course and radiologic findings of each patient, including autopsy findings of three patients who died, were described.

RESULTS

Four patients received treatment in the ICU. Elevated urinary nickel concentration was detected in all patients. Results of extensive microbiological investigations were unremarkable. No patients received chelating agents. Pulmonary consolidation, edema, hemorrhage, and fibrosis were observed at autopsy in patients who died. An out-of-date chemical used during neutralization of nickel waste was implicated as the source of nickel carbonyl poisoning.

CONCLUSIONS

High mortality was reported in patients who presented subacutely following nickel carbonyl exposure. Further studies should be performed to clarify the role of chelation therapy in the subacute phases following nickel carbonyl exposure.

Close temporal association of bronchial asthma and ischemic colitis--case report and review of the literature

We report a case of ischemic colitis in an elderly male who had initially presented with acute asthma exacerbation. The clinical course of hospitalization, surgical and pathological findings were described. We review three previously reported cases of ischemic colitis and bronchial asthma and explore possible mechanisms to explain this association. The complex interaction of smooth muscle tone and autonomic nervous system in the etiopathogenesis of bronchial asthma and ischemic colitis is discussed. Further studies should be undertaken to clarify this association.

An outbreak of primary dengue infection among migrant Chinese workers in Singapore characterized by prominent gastrointestinal symptoms and a high proportion of symptomatic cases

BACKGROUND

An outbreak of dengue occurred among Chinese migrant workers at a construction site in Singapore that was characterized by a number of unusual features.

METHODS

Clinical and laboratory data were prospectively collected from workers who were hospitalized with fever. We compared the frequency of disease manifestations in these patients with historical data from other cases of dengue admitted to the same centre. A serological survey was performed at the construction site one month after the onset of the outbreak.

RESULTS

Thirty-nine patients were admitted from the affected construction site with confirmed acute dengue infection in March and April 2002. Fever, headache and rash were common and occurred at similar frequency in outbreak patients and historical controls. Gastrointestinal manifestations were significantly more common in the outbreak patients compared with controls (nausea 68%, diarrhea 41%, hyponatremia 47% and elevated urea 20%). Of the 274 studied in the serological survey, 27 had serological evidence of acute dengue, of whom 24 (89%) had experienced a febrile illness in the previous month. The virus was cultured and identified as Dengue-2. Few patients had a positive IgG for dengue indicating that this was likely a primary infection.

CONCLUSION

This outbreak of primary dengue infection was characterized by unusually prominent gastrointestinal symptoms and a high proportion of symptomatic transmission. Manifestations of dengue may be altered when outbreaks involve immunologically naïve adults who have migrated to dengue endemic areas.

Symptomatic segmental dystonia from a cavernous angioma in the centrum semiovale

We describe a 68 year-old Chinese man who presented with segmental dystonia involving the neck and right upper limb, which was exacerbated with action. EEG and MRI of the cervical spine were unremarkable, but MRI of the brain revealed a small cavernous angioma measuring one centimeter in diameter in the left centrum semiovale. The dystonia was ameliorated but not abolished with trihexyphenidyl. Arteriovenous malformations have been described to cause movement disorders, but dystonia has not previously been reported in association with cavernous angiomas. A search of the literature revealed one report of a patient with chorea arising from a cavernous angioma. This interesting case illustrates how an uncomplicated cavernous angioma can rarely cause segmental dystonia and highlights the importance of neuroimaging in patients with late-onset movement disorders.