Conduction properties of spinal cord axons in the myelin-deficient rat mutant.

Spinal cords of myelin-deficient and normal age-matched (control) rats were removed and their conduction and pharmacological properties studied in an in vitro brain slice chamber. The conduction velocity of the myelin-deficient dorsal column axons was reduced to about 25% of control axons; however, the amyelinated myelin-deficient axons displayed refractory periods and the ability to sustain high-frequency action potential discharge similar to that of dorsal column axons in control rats. Pharmacological results suggest that the myelin-deficient dorsal column axons qualitatively express a normal complement of ion channels and receptors. The demonstration of a normal representation of channels and receptors on these axons supports the proposal that the oligodendrocyte, and not the axon, is the site of the primary defect in the myelin-deficient rat mutant. It is concluded that, unlike acutely demyelinated axons which display marked frequency-dependent conduction block, amyelinated axons of the myelin-deficient rat spinal cord develop compensatory mechanisms to stabilize action potential conduction.     

Neurokinin A with K channel blockade potentiates contraction to electrical stimulation in human bronchus

This study investigated the effects of neurokinin A (NKA) on cholinergic neural responses in human bronchus. NKA (0.1 nM) did not alter the contractile response to submaximal electrical field stimulation. However, K⁺ channel blockade with 4-aminopyridine (4-AP) (0.1 mM) potentiated the response to electrical field stimulation (to 182 ± 25% of control, n = 4, P < 0.05) and subsequent addition of NKA in the presence of 4-AP produced further potentiation (to 123 ± 6% of the response to 4-AP n = 4, P < 0.05). Neither 4-AP (0.01 or 0.1 mM) nor NKA in the presence of 4-AP potentiated the actions of exogenous acetylcholine but in these experiments 4-AP itself produced a marked direct contractile response. Thus NKA in the presence of K⁺ channel blockade potentiates cholinergic neural response in human bronchus and this occurs at a prejunctional site.     

Thrombus causing fatal left ventricular outflow tract obstruction in a heart transplant patient

A 60 year male, orthotopic heart transplant recipient developed a fatal left ventricular outflow obstruction secondary to thrombus at 38 months post transplant. Although he had episodes of mild to moderate rejection at 2 and 16 months post transplant, subsequent biopsies were negative and annual cardiac catheterizations showed mild left ventricular hypokinesis and normal coronary arteries. This case represents a catastrophic complication of transplant rejection and illustrates the problems with identifying rejection using current diagnostic methods.     

Spinal cord compression by spontaneous spinal subdural haematoma in polycythemia vera.

A woman with an eight-year history of polycythemia vera presented with numbness and weakness of both legs. A large spinal haematoma was revealed on magnetic resonance imaging which was treated clinically and which subsequently resolved.     

Psychotic symptoms and age of onset in affective disorders.

Prevalence of hallucinations and delusions was studied in 1,763 patients with unipolar major depression, bipolar affective disorder, and schizoaffective disorder. The authors found that the presence of psychotic features was negatively associated with age of onset for the group as a whole, and bipolar affective disorder (manic or mixed type) specifically. The clinical implications of the findings are discussed.     

Expression of Epidermal Growth Factor Receptors in Human Breast Cancer: Mass Versus Ligand Binding Capacity

Abstract: Thirty percent of lymph node-negative women with primary breast cancers are at high risk for early recurrence of metastatic disease and diminished survival. Identification of these high-risk patients is a long-term objective of our laboatory, and the epidermal growth factor receptor (EGFR) was investigated as a prognostic factor, EGFR was measured by a ligand binding assay developed in house, in the competition mode that served as the "gold standard" for assessing receptor content and activity. In contrast, measurements of mass (content) were performed by an enzyme immunoassay (EIA) from Ciba Corning Diagnostics (Alameda, CA) and by an enzyme-linked immunosorbent assay (ELISA) from Oncogene Science (Uniondale, NY). A total of 78 breast carcinomas were examined. The median binding capacity measured with [¹²⁵I]EGF was 13 fmol/mg membrane protein (range 0–981), that measured by EIA was 8 fmol/mg (range 1–125), while EGFR measured by ELISA was 135 (range 0–751). Distribution of EGFR did not appear to vary as a function of patient age. Neither the results from EIA nor those from ELISA correlated with those obtained by the ligand binding assay. However, there was a good correlation of results obtained by the two antibody-based assays despite the fact that the calibration of standards was considerably different. These data suggest that EGFR should be measured by ligand binding assay for clinical studies; mass assays based on antibody reagents will require further development.     

High resolution computed tomography as a predictor of lung histology in systemic sclerosis

Background The relative proportions of fibrosis and inflammation seen by open lung biopsy examination is a predictor of disease outcome in fibrosing alveolitis. This study was designed to assess the ability of high resolution computed tomography to predict the histological appearance of open lung biopsy specimens from patients with systemic sclerosis.