Detection of myasthenia gravis using electrooculography signals.

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder resulting from skeletal muscle weakness and fatigue. An early common symptom is fatigable weakness of the extrinsic ocular muscles; if symptoms remain confined to the ocular muscles after a few years, this is classified as ocular myasthenia gravis (OMG). Diagnosis of MG when there are mild, isolated ocular symptoms can be difficult, and currently available diagnostic techniques are insensitive, non-specific or technically cumbersome. In addition, there are no accurate biomarkers to follow severity of ocular dysfunction in MG over time. Single-fiber electromyography (SFEMG) and repetitive nerve stimulation (RNS) offers a way of detecting and measuring ocular muscle dysfunction in MG, however, challenges of these methods include a poor signal to noise ratio in quantifying eye muscle weakness especially in mild cases. This paper presents one of the attempts to use the electric potentials from the eyes or electrooculography (EOG) signals but obtained from three different forms of sleep testing to differentiate MG patients from age- and gender-matched controls. We analyzed 8 MG patients and 8 control patients and demonstrated a difference in the average eye movements detected between the groups. A classification accuracy as high as 68.8% was achieved using a linear discriminant analysis based classifier.

The multidimensionality of sleep quality and its relationship to fatigue in older adults with painful osteoarthritis.

OBJECTIVE: To evaluate subjective sleep quality and its relationship to fatigue in older adults with osteoarthritis (OA). METHOD: In a community cohort with hip/knee OA, subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and fatigue was measured by the Profile of Mood States - Fatigue subscale (POMS-F). Correlates of sleep quality and fatigue were determined by standardized interviews including socio-demographics, OA severity (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) summary score), comorbidity, depression (Center for Epidemiologic Studies Depression Scale, CES-D), stressful life events, daytime napping, symptoms of restless legs syndrome (RLS) and prior sleep disorder diagnoses. Logistic regression examined correlates of poor sleep (PSQI score>5). Linear regression evaluated the relationship between poor sleep and fatigue, and the effect of napping on this relationship. RESULTS: In 613 respondents, mean age was 78 years, 78% were female, 11% had concomitant fibromyalgia, and 26% had 3+ comorbid conditions. Responses indicated moderate OA severity. Seventy percent reported poor sleep; 25% met criteria for RLS and 6.5% reported a diagnosed sleep disorder. Independent correlates of poor sleep were: greater arthritis severity (adjusted odds ratio (OR) per unit increase in WOMAC score=1.03, P<0.0001), 3+ comorbid conditions (adjusted OR=1.88; P=0.03), depressed mood (adjusted OR per unit increase in CES-D score=1.09, P<0.0001), and RLS (adjusted OR=1.87; P=0.02). Controlling for previously reported fatigue correlates, poor sleep was significantly associated with greater fatigue (parameter estimate=1.63, P=0.0003) and napping did not moderate this relationship (P=0.55 for the interaction between napping and poor sleep). CONCLUSIONS: Among older people with OA, poor sleep is highly prevalent and significantly linked with fatigue. Identifying the nature of sleep disturbances in OA is important as treatment of sleep disturbances may reduce OA-related fatigue.

An unusual case of trisomy and triploidy in a chorion villus biopsy.

A case is reported of a 35-year-old woman who underwent a chorion villus biopsy (CVB) at 17 weeks' gestation after intrauterine growth retardation and oligohydramnios were diagnosed by ultrasound scan. Chromosome analysis of the CVB direct preparations showed a 47,XX,+6 karyotype in all cells. The pregnancy was terminated and subsequent analysis of cultured cells from both the CVB and the post-mortem placenta showed three cell lines: 46,XX, 47,XX,+6 and 69,XXX, while fetal skin and muscle were entirely 69,XXX. An explanation is proposed for the origin and distribution of the three cell lines.

The effect of early labour, maternal analgesia and fetal acidosis on fetal plasma oxytocin concentrations.

OBJECTIVE: To determine the effect of early labour, maternal analgesia and fetal hypoxia on circulating fetal oxytocin concentrations. DESIGN: Prospective observational study. SETTING: Delivery suite in a District General Hospital. SUBJECTS: Fifty women at term who did not require oxytocin administration or more than one form of analgesia. Study groups: vaginal delivery with (1) no analgesia, (2) pethidine, or (3) epidural analgesia. Caesarean section under regional analgesia (4) prior to, and (5) after the onset of labour. INTERVENTIONS: Samples of blood were collected from the umbilical artery (UA) and umbilical vein (UV) immediately after fetal delivery prior to placental separation or oxytocic administration. MAIN OUTCOME MEASURES: Plasma oxytocin (OT) concentration, umbilical vein pH, cystine aminopeptidase activity. RESULTS: The geometric mean UA-OT was significantly greater than UV-OT in all groups and was not altered by pethidine; however, epidural administration increased the UA-UV difference. The UA-UV difference at caesarean section was not significantly altered by the onset of labour. There was no correlation between UV pH and UA-UV plasma oxytocin. Cystine aminopeptidase activity was not detectable in UA and UV plasma. CONCLUSIONS: Fetal OT production is increased by epidural but not by pethidine analgesia. It is not influenced by the onset of labour or fetal hypoxia.

Thiazolidine-diones. Biochemical and biological activity of a novel class of tyrosine protein kinase inhibitors.

Various derivatives of thiazolidine-diones have been identified as tyrosine protein kinase inhibitors. The epidermal growth factor (EGF) receptor kinase and c-src kinase were inhibited in vitro with IC50 values in the range of 1-7 microM. The v-abl tyrosine protein kinase was not inhibited by thiazolidine-diones. Inhibition was found to be specific for tyrosine protein kinases. Inhibition of serine/threonine protein kinases was not observed. The active derivatives were shown to inhibit EGF-induced receptor autophosphorylation, either in vitro or in intact cells, and were also found to inhibit growth of the EGF-dependent BALB/MK and A431 cell lines (IC50 1-3 microM). Growth of the interleukin-3-dependent myeloid cell line FDC-P1 was inhibited with equal efficiency. Thus, in these cell lines, members of the c-src kinase family are also potential targets for inhibition by the compounds.

Medical complications of herpes zoster in immunocompetent patients.

The vast majority of the more than 300,000 annual cases of herpes zoster in the United States occur among healthy, immunocompetent persons. Most patients recover from reactivated varicella-zoster infection, but some experience complications. The most common of these is postherpetic neuralgia, but other neurologic as well as ocular and dermatologic complications can occur as well. Zoster during pregnancy is not of serious concern. Ongoing trials of antiviral agents are aimed at resolving the infection quickly and decreasing the incidence and severity of postherpetic neuralgia.

The polypeptide structure and assembly of Ly-2/3 heterodimers.

Mild reduction of mature, thymic Ly-2/3 heterodimers of Mr 67 000 resulted in dissociation into three individual polypeptide chains, alpha, alpha', and beta, of respective Mr values 38 000, 35 000, and 30 000. The alpha and alpha' chains were both immunoprecipitated by a monoclonal antibody directed to the Ly-2.1 epitope whereas the Ly-3.1 antibody bound only the beta chain. The possibility that the alpha and beta chains of each heterodimer established their interchain links within a labile precursor protein in which alpha and beta segments were fused was considered but discounted by the finding that in mice heterozygous for both Ly-2 and Ly-3 loci, the Ly-2 product of one chromosome was not exclusively joined to Ly-3 structures coded by the same chromosome. By utilizing ionic detergents which selectively alter the charge of intrinsic membrane proteins, both Ly-2 and Ly-3 polypeptides were shown to have membrane insertion sites. It is suggested that as a consequence of their likely synthesis on membrane-bound polysomes, newly synthesized Ly-2 and Ly-3 structures accumulate within the same subcellular compartment - the membranes of the rough endoplasmic reticulum. Their elevated concentration within this space may facilitate a low affinity binding interaction between Ly-2 and Ly-3 which is later stabilized by interchain disulfide bond formation.

Medical complications of infectious mononucleosis.

Infectious mononucleosis is usually a benign, self-limited disease, but complications may develop in up to 5 percent of patients. The complications can be life-threatening and may precede, follow or coincide with the usual symptoms of infectious mononucleosis. Occasionally, a complication is the only clinical manifestation of the disease. Complications may be due to an autoimmune response, a lymphocytic infiltrative reaction, generalized edema of the airway tissues or enlargement of the spleen.

Comparison of thymic and peripheral T cell Ly-2/3 antigens.

Major structural differences occur between the thymic and peripheral T cell forms of the Ly-2/3 antigen. Thymus Ly-2/3 consists of similar amounts of two types of disulfide-linked heterodimer, alpha beta and alpha' beta (Mr alpha = 38000, Mr alpha' = 35000, Mr beta = 30000). In contrast material from peripheral T cells consists almost exclusively of alpha beta dimers. The alpha chains of thymus and peripheral T cells differ also in isoelectric point with the thymic alpha chain being the more acidic. Based on peptide mapping experiments the alpha and alpha' chains of thymus are likely to be alternatively modified forms of the same polypeptide backbone. Individual T cell clones or T cell tumors propagated in vitro exhibit either a typical thymus or a typical peripheral T cell Ly-2/3 polypeptide pattern indicating that the synthesis of both alpha and alpha' chains can occur in the same cell. The heterogeneity of thymic Ly-2/3 can be considerably reduced by removal of sialic acid residues, and after desialylation the alpha chains of thymus and a cloned cytotoxic T lymphocyte (CTL) line cannot be electrophoretically distinguished. If Ly-2 structures affected the antigen specificity of CTL, a different structural variant would be expected in individual clones. The electrophoretic identity of desialylated thymus and CTL alpha chains suggests that Ly-2 does not exhibit clonal variation in polypeptide structure and, therefore, cannot contribute to antigen specificity.