Influence of the shape of intracellular potentials on the morphology of single-fiber extracellular potentials in human muscle fibers

Attention of the investigators is usually pointed to the peak-to-peak characteristics of single-fiber action potentials (SFAPs) that are mainly determined by the depolarizing phase of the intracellular action potential (IAP). However, the final portion of the SFAP has often specific shape that has to be related to peculiarities of the repolarization phase of IAP and the duration of its spike. A novel piecewise SFAP model is proposed to achieve greater insight into the nature of declining portion of the negative phase and of the third phase of SFAP. It was found that the SFAP third phase is essentially determined by the specific profile of the transition of the IAP falling phase toward the resting voltage, whereas the SFAP declining negative phase is more dependent upon the width of the corresponding IAP spike. We tentatively suggest that the duration of the spike of human IAPs should be over approximately 0.75 ms.     

The meaning of suffering in drug addiction and recovery from the perspective of existentialism, Buddhism and the 12-Step program

The aim of the current article was to examine the meaning of suffering in drug addiction and in the recovery process. Negative emotions may cause primary suffering that can drive an individual toward substance abuse. At the same time, drugs only provide temporary relief, and over time, the pathological effects of the addiction worsen causing secondary suffering, which is a motivation for treatment. The 12-Step program offers a practical way to cope with suffering through a process of surrender. The act of surrender sets in motion a conversion experience, which involves a self-change including reorganization of one's identity and meaning in life. This article is another step toward understanding one of the several factors that contribute to the addict's motivation for treatment. This knowledge may be helpful for tailoring treatment that addresses suffering as a factor that initiates treatment motivation and, in turn, treatment success.     

CD28: Direct and Critical Receptor for Superantigen Toxins

Every adaptive immune response requires costimulation through the B7/CD28 axis, with CD28 on T-cells functioning as principal costimulatory receptor. Staphylococcal and streptococcal superantigen toxins hyperstimulate the T-cell-mediated immune response by orders of magnitude, inducing a lethal cytokine storm. We show that to elicit an inflammatory cytokine storm and lethality, superantigens must bind directly to CD28. Blocking access of the superantigen to its CD28 receptor with peptides mimicking the contact domains in either toxin or CD28 suffices to protect mice effectively from lethal shock. Our finding that CD28 is a direct receptor of superantigen toxins broadens the scope of microbial pathogen recognition mechanisms.     

Prenatal application of the individualized fetal growth reference

The individualized reference for defining small for gestational age (SGA) at birth has gained popularity in recent years. However, its utility on fetal assessment has not been evaluated. The authors compare an individualized with an ultrasound reference in predicting poor perinatal outcomes. Data from a large clinical trial in predominantly white US women (1987-1991) with singleton pregnancies (n = 9,526) were used. The individualized reference classified fewer SGA fetuses than the ultrasound reference, but the risks of adverse outcomes were similar between fetuses classified by both references. The risk increased substantially only when the percentiles fell below the 5th percentile (likelihood ratio positive at birth = 2.68 (95% confidence interval (CI): 2.00, 3.58) and 3.13 (95% CI: 2.34, 4.18) for ultrasound and individualized references, respectively). SGA fetuses defined by either the individualized or ultrasound reference alone had risk ratios of adverse outcomes of 1.91 (95% CI: 0.77, 4.77) and 1.18 (95% CI: 0.37, 3.77), respectively, compared with normal fetuses (the difference between these 2 risk ratios, P = 0.71). The authors conclude that neither the ultrasound-based nor the individualized reference does well in predicting adverse perinatal outcomes. The 5th percentile may be a better cutpoint than the 10th percentile in defining SGA.     

Intra-word inconsistency in apraxic Hebrew-speaking children

Intra-word inconsistency in a child is perceived as an indicator of speech impairment. Because the speech of typically developing children is highly variable, the extent and nature of the inconsistency must be defined when used as a diagnostic marker of speech impairment (McLeod, S., & Hewett, S. R. (2008). Variability in the production of words containing consonant clusters by typical 2- and 3-year-old children. Folia Phoniatrica et Logopaedica, 60(4), 163-172). In this paper, we study inconsistency with reference to the prosodic hierarchy (McCarthy, J. J., & Prince, A. S. (1996). Prosodic morphology 1986. Amherst, MA: University of Massachusetts. Retrieved April 15, 2010, from http://ruccs.rutgers.edu/pub/papers/pm86all.pdf), suggesting a new way to describe this phenomenon in childhood apraxia of speech (CAS). The prosodic hierarchy has been used in recent years to demonstrate the phonological development of typical and atypical populations. Sixteen children diagnosed with CAS (average age 3;11) participated in the study. The data, collected from each child in the course of eight weekly meetings, are drawn from naming single words. The results indicate that inconsistency is dominant for two prosodic levels, the segmental and the syllabic, while the prosodic word level was largely preserved.     

Morbidity and hospitalizations of adults with Down syndrome

Over the last decade a significant increase in the life expectancy of people with Down syndrome (DS) has been observed, which has caused a higher incidence of morbidity as they age. However, there is a lack of literature regarding morbidity and hospitalization of adults with DS. Analysis of 297 hospitalizations of 120 adults with DS aged 18-73 years hospitalized at Hadassah Medical Centers during the years 1988-2007 compared with data of the general population, hospitalized at the same period. At the age range 18-66 years, mean number of hospitalizations was significantly higher than the general population (P = 0.000001) with hospitalization also significantly longer (P = 0.0009). Exceptionally long hospitalizations were seen at the departments of internal medicine, dermatology and intensive care units. There was no significant difference in mortality between DS and the general population (P = 0.221). More than a fourth of the hospitalizations were caused by infectious diseases, mostly respiratory infections. Hypothyroidism was more prevalent compared with the estimated number reported by the literature (30.8% vs. 15%). Convulsive disorder was prevalent as well (15.8%). However, the prevalence of congenital heart disease, dementia, osteoporosis and obesity was found less than expected. Adults with DS are hospitalized more than the general population and for longer duration. The results of this study emphasize the need for preventive community-based medicine, awareness of co-morbidities and possible deterioration and to prepare the medical staff for a complex course of illness, expecting longer hospitalizations, arising from the complexity of this population.