Naturally Occurring Polymers of IgA Lacking J Chain

Two of twenty IgA myeloma proteins studied were found to lack J chain. Both IgA proteins contained dimers and higher polymers (trimers, tetramers, pentamers) in proportions similar to those found in most classical 'J-positive' proteins. Both the 'J-negative' proteins contained bound albumin and alpha-1 anti-trypsin (α1AT), and reduction with mercaptoethylamine caused a release of albumin and α1AT concomitant with depolymerization of the higher polymers of IgA. These proteins formed complexes with secretory component (SC) in vitro, indicating that the presence of J chain is not a requirement for SC binding.     

Treatment of paragangliomas with radiation therapy

Paragangliomas of the head and neck may be treated successfully with surgery, radiation therapy, or stereotactic radiosurgery. The choice of treatment depends on the location and extent of the tumor, the presence of multiple tumors, the age and health of the patient, and the preference of the patient and attending physician. This article reviews the role of radiation therapy in the treatment of patients with paragangliomas of the head and neck.     

Squamous cell carcinoma metastatic to the neck from an unknown head and neck primary site

Squamous cell carcinoma metastatic to the neck from an unknown head and neck primary site is relatively uncommon and presents a challenging diagnostic and therapeutic dilemma. Diagnostic evaluation includes fine-needle aspiration of the neck mass, chest roentgenography, computed tomography, and/or magnetic resonance imaging of the head and neck, followed by panendoscopy and biopsies. The primary tumor will be detected in approximately 40% of patients; approximately 80% of cancers are located in the base of the tongue or tonsillar fossa. Management options include treatment of the neck alone or both sides of the neck and the potential head and neck primary sites. The latter approach is associated with better long-term control above the clavicles. The 5-year survival rate is approximately 50% after treatment and is influenced by the extent of neck disease. In this article, we review the pertinent literature.     

Prolonged QT interval and cardiac arrhythmias in two neonates: sudden infant death syndrome in one case

Two neonates with arrhythmias and the long QT syndrome are described. The arrhythmias were detected in utero and both infants were apparently well after birth. The first infant, although well, had a bradycardia for the first 9 days of life. A normal heart rate was documented at 10 days but a prolonged QT interval was not appreciated on the ECG. He was discharged from hospital but died suddenly and unexpectedly 3 days later. A post-mortem examination failed to find a cause for his death which therefore fell into the category of the sudden infant death syndrome (SIDS). A retrospective analysis of the perinatal electrocardiogram showed a probable junctional rhythm with 2:1 conduction to the ventricle; the QT interval was prolonged at 0.52 seconds (QTC = 0.63). The second infant had a QT interval of 0.52 seconds (QTC = 0.54) and frequent ventricular premature beats on a 24-hour electrocardiogram. She was treated with propranolol and remains well 2 years later. Sudden infant death has often been described in the siblings of children with the long QT syndrome and one other report described a case of SIDS which was said to have had a prolonged QT interval on the perinatal ECG. This report, however, provides unquestionable evidence, in one case, of an association between the long QT syndrome and SIDS.     

Determinants of occupational disability following a low back injury: a critical review of the literature

The aim of this research was to determine prognostic indicators of work disability in occupational back pain as reported in the literature, by systematically searching the research literature, assessing the methodological quality of the research, and synthesizing the findings into a concise summary. An article was considered eligible for review if research participants had an injury of the back, the article was based on original research, published in English, and involved a cohort with back pain less than 6 months post injury with at least one follow up assessment. Each article was independently reviewed by two blinded reviewers using 19 appraisal criteria for methodological quality of prognostic studies. Nineteen studies met the methodological standard to be included. Time since onset, demographic factors, functional disability, psychological distress, pain reports, previous episodes, and work environment were identified as important prognostic factors. Most studies compartmentalized the factors they considered. What is needed is a comprehensive multivariate biopsychosocial job-related model of work disability.     

Evaluation of the Sheffield system for identifying children at risk from unexpected death in infancy. Results from Birmingham and Newcastle upon Tyne

The "at birth" system which is used in Sheffield to identify children likely to die unexpectedly in infancy, was tested retrospectively in Birmingham (83 cases) and in Newcastle upon Tyne (56 cases). The discrimination between cases and age-matched controls was poor in both cities. Analysis of the 8 factors used in the system showed that only 2 maintained significant case/control differences in Birmingham and Newcastle. Further investigation showed that other factors from maternity records showed significant case/control differences in these cities. Although the system used in Sheffield would not be of use in a prospective prevention programme in either Newcastle or Birmingham, the possibility of evolving an "at risk" system which might apply more widely is discussed.     

Diagnosis of recurrent cervical carcinoma after radical hysterectomy

A standard surveillance program for cervical carcinoma patients treated with radical hysterectomy is reviewed. Between 1962-1984, 249 patients with stage IB cervical carcinoma treated with radical hysterectomy and pelvic lymphadenectomy were entered in the surveillance program. Of the 27 patients (11%) diagnosed with recurrent carcinoma, 17 (63%) were identified by clinical history, 22 (81%) by physical examination, five (18%) by vaginal cytology, six (22%) by chest radiography, and eight (30%) by renal contrast imaging. Combined clinical history and physical examination identified 24 patients (89%) with recurrent carcinoma. Disease recurrence was detected by vaginal cytology in one asymptomatic patient with a normal examination. The recommended surveillance procedures for patients with cervical carcinoma after radical hysterectomy include clinical history, physical examination, and vaginal cytology. Chest radiography and renal contrast imaging should be reserved for symptomatic patients.     

Energy failure in astrocytes increases the vulnerability of neurons to spreading depression

A neuroprotective role of astrocytes has been hypothesized, but the mechanism is debated and in vivo evidence is limited. To test this hypothesis, a sublethal stressor (spreading depression) and fluorocitrate (FC), a selective inhibitor of the astrocytic Krebs cycle, were used in urethane-anaesthetized adult rats. Neuronal damage was assessed 24 h after treatment with silver stain and immunoreactivity for a 72-kDa heat-shock protein. ATP levels and mitochondrial aconitase activity, a marker indicating exposure to reactive oxygen species, were measured after 4 and 24 h. Spreading depression alone did not affect ATP levels, mitochondrial aconitase activity, or induce neuronal injury in the cortex. Local or intraventricular injection of FC significantly decreased ATP levels and mitochondrial aconitase activity, but did not produce neuronal damage. In animals receiving injections of FC and then spreading depression, there was evidence of significant neuronal stress and damage. Isocitrate, which bypasses the metabolic inhibition produced by FC, prevented all of the changes seen after the combination of FC and spreading depression. One-hour pretreatment with dimethyl sulfoxide (a scavenger of hydroxyl radicals), deferoxamine (an iron chelator) or fructose-1,6-bisphosphate also blocked inactivation of mitochondrial aconitase, ATP depletion and the neuronal damage induced by FC and spreading depression. These experiments demonstrate that inhibition of the metabolism of astrocytes, with a decrease in ATP levels, will increase the susceptibility of neurons to the stress induced by spreading depression. The neuroprotective effects of dimethyl sulfoxide, deferoxamine and fructose-1,6-bisphosphate suggest that oxidative stress contributes to the neurotoxicity in this situation.