Antigenic and immunologic characterization of an allogeneic colon carcinoma vaccine

In the present prospective, census-based study we have investigated the prevalence of organ-specific and non-organ-specific autoantibodies (AAb) in 152 unselected Cameroonians aged 60 years and older living in the community. AAb were detected in 49% of the participants. Non-organ-specific AAb (47%) predominated over organ-specific AAb (7%). Anti-TPO, anti-Tm, anti-Tg and anti-PC AAb were completely absent. RF was the most frequent AAb, being found in 57 (38%) cases. The prevalences of anti-SMA and RF were significantly higher in women than in men (respectively, P=0.023 and P=0.016). Higher serum concentrations of gammaglobulins were accompanied by a higher prevalence of RF (P < 0.0001) and a lower prevalence of ANA (P=0.036). The overall prevalence of AAb was higher in the filaria-infected (60%) compared to the non-infected (42%) participants (P=0.046). There was no significant influence of the vitamin D status, number of pregnancies, physical activity or medication use on the prevalence of AAb. In this study a heterogeneous pattern for the presence of the various AAb was found. Some AAb, which are commonly encountered in other studies on elderly subjects, were completely absent in this population. This diversified pattern of AAb prevalence therefore argues in favour of exogenous influences in the occurrence of AAb in elderly populations.     

Metformin during pregnancy reduces insulin, insulin resistance, insulin secretion, weight, testosterone and development of gestational diabetes: prospective longitudinal assessment of women with polycystic ovary syndrome from preconception throughout pregnancy

BACKGROUND: In a prospective observational study of 42 pregnancies in 39 Caucasian women (age 30 +/- 4 years) with polycystic ovary syndrome (PCOS), we examined effects of metformin on maternal insulin, insulin resistance (IR), insulin secretion (IS), weight gain, development of gestational diabetes (GD), testosterone and plasminogen activator inhibitor activity. We assessed the hypothesis that diet-metformin (MET) lessens the physiological gestational increase in IR and reduces gestational weight gain, thus reducing GD. METHODS: Preconception, in an out-patient clinical research centre, MET 1.5 (eight pregnancies) to 2.55 g/day (34 pregnancies) was started. Women with body mass index <25 or >or=25 kg/m(2) were given a 2000 or 1500 calorie/day, high-protein (26% of calories), low-carbohydrate (44%) diet. Calorie restrictions were dropped after conception. RESULTS: On MET, GD developed in three out of 42 pregnancies (7.1%). Median entry weight (94.5 kg) fell to 82.7 on MET at the last preconception visit (P = 0.0001), fell further to 81.6 during the first trimester, was 83.6 in the second trimester, and 89.1 kg in the third trimester. Median weight gain during pregnancy was 3.5 kg. The median percentage reduction in serum insulin was 40% on MET at the last preconception visit; insulin did not increase in the first or second trimesters (P > 0.05), and rose 10% in the third trimester. The median percentage reduction in HOMA IR was 46% on MET at the last preconception visit; IR did not increase (P > 0.05) in the first, second or third trimesters. HOMA insulin secretion fell 45% on MET at the last preconception visit, did not increase in the first trimester, rose 24% in the second trimester, and rose 109% in the third trimester. Testosterone fell 30% on MET at the last preconception visit (P = 0.01) and then rose 74, 61 and 95% during trimesters 1, 2 and 3; median testosterone during the third trimester did not differ from pre-treatment levels. CONCLUSIONS: By reducing preconception weight, insulin, IR, insulin secretion and testosterone, and by maintaining these insulin-sensitizing effects throughout pregnancy, MET-diet reduces the likelihood of developing GD, and prevents androgen excess for the fetus.     

The control of retinogeniculate transmission in the mammalian lateral geniculate nucleus

Summary In the mammalian visual system, the lateral geniculate nucleus is commonly thought to act merely as a relay for the transmission of visual information from the retina to the visual cortex, a relay without significant elaboration in receptive field properties or signal strength. However, many morphological and electrophysiological observations are at odds with this view. Only 10–20% of the synapses found on geniculate relay neurons are retinal in origin. Roughly half of all synapses derive from cells in layer VI of visual cortex; roughly one third are inhibitory and GABAergic, derived either from interneurons or from cells of the nearby perigeniculate nucleus. Most of the remaining synapses probably derive from cholinergic, noradrenergic, and serotonergic sites within the brainstem reticular formation. Moreover, recent biophysical studies have revealed several ionic currents present in virtually all thalamic neurons. One is a Ca²⁺-dependent K⁺ current underlying the afterhyperpolarization (or the I_AHP), which may last up to 100–200 ms following an action potential. Activation of the I_AHP leads to spike frequency adaptation in response to a sustained, suprathreshold input. Intracellular recordings from other neuronal preparations have shown that the I_AHP can be blocked by noradrenalin or acetylcholine, leading to an increased cellular excitability. Another ionic current results from a voltage- and time-dependent Ca²⁺ conductance that produces a low threshold spike. Activation of this conductance transforms a geniculate neuron from a state of faithful relay of information to one of bursting behavior that bears little relationship to the activity of its retinal afférents. We propose that state-dependent gating of geniculate relay cells, which may represent part of the neuronal substrate involved in certain forms of selective visual attention, can be effected through at least three different mechanisms: (1) conventional GABAergic inhibition, which is largely controlled via brainstem and cortical afferents through interneurons and perigeniculate cells; (2) the I_AHP, which is controlled via noradrenergic and cholinergic afferents from the brainstem reticular formation; and (3) the low threshold spike, which may be controlled by GABAergic inputs, cholinergic inputs, and/or the corticogeniculate input, although other possibilities also exist. Furthermore, it seems likely that gating functions involving the corticogeniculate pathway are suited to attentional processes within the visual domain (e.g., saccadic suppression), whereas brain-stem inputs seem more likely to have more global effects that switch attention between sensory systems. In any case, it is now abundantly clear that geniculate circuitry and the intrinsic electrophysiological properties of geniculate neurons are no longer compatible with the notion that the lateral geniculate nucleus serves as a simple relay.     

Fragile X CGG repeat structures among African-Americans: identification of a novel factor responsible for repeat instability

The cryptic CGG repeat responsible for the fragile X syndrome, located in the 5'-UTR of FMR1, is unique compared with the many other triplet repeat-causing diseases, making it ideal for identifying factors involved in repeat expansion that may be common to other triplet repeat diseases. To date, a number of factors have been identified which may influence repeat instability, including the number and position of interspersed AGGs, length of the 3' pure CGG repeat and haplotype background. However, nearly all such data were derived from studies of Caucasians. Using a large African-American population, we present the only comprehensive examination of factors associated with CGG repeat instability in a non-Caucasian population. Among Caucasians, susceptible alleles were thought to come from those in the intermediate repeat range (41-60 repeats); however, we find that susceptible alleles may come from a larger repeat pool (35-60 repeats) and are better defined by their pure CGG repeat and/or -presence of only one AGG interruption. These results demonstrate the existence of different susceptible alleles among world populations and may account for the similar prevalence of the fragile X syndrome in African-Americans compared with Caucasians despite the lower frequency of inter-mediate sized alleles in the African-American population. Finally, we show that repeat structures among unaffected African-Americans with the most frequent fragile X haplotype background are either pure or contain a single distal interruption. We propose that the lack of a proximal most interruption is a novel factor involved in CGG repeat instability.     

Shoulder muscle activity in Parkinson’s disease during multijoint arm movements across a range of speeds

Bradykinesia is one of the primary symptoms of Parkinson disease and leads to significant functional limitations for patients. Single joint movement studies, that have investigated the mechanism of bradykinesia, suggest that several features of muscle activity are disrupted, including modulation of burst amplitude and duration, and the number of bursts. It has been proposed that it is the blending of these different burst deficits that collectively defines bradykinesia. This study adds two new approaches to the study of bradykinesia. First, we examined the features of shoulder muscle activities during multijoint arm movement in bradykinetic and control subjects, such that previously reported single joint hypotheses could be tested for generalized arm movement. Second, we directly manipulated speed while keeping distance constant for a large range of speeds. In this manner, we could compare individual trials of muscle activity between controls and subjects with Parkinsons disease (PD) for movements matched for both speed and movement duration. Our results showed that while a multiple burst pattern of shoulder muscles was a common strategy for all subjects (young, elderly controls and PD), subjects with PD showed several burst abnormalities, including deficits in initial agonist burst amplitude and duration at both fast and slow speeds. Subjects with PD also (1) failed to produce a one-burst pattern at fast speeds and, instead, produced a predominance of multiple burst patterns and (2) showed a relationship between the number of burst deficits and the severity of disease. These results extend the findings of single joint studies to multi-joint and similarly indicate that a combination of burst modulation abnormalities correlate with bradykinesia and disease severity.     

Peripheral tolerance to an islet cell-specific hemagglutinin transgene affects both CD4+ and CD8+ T cells.

To study the basis for immunological tolerance of peripheral tissue-specific antigens, a transgenic mouse line was established that expresses the influenza hemagglutinin (HA) on pancreatic islet beta cells (Ins-HA transgenic mice). When followed up to 14 months of age, Ins-HA transgenic mice did not develop spontaneous autoimmune disease. Upon immunization with HA-expressing viruses, high titers of HA-specific circulating antibody were detected; however, T cell responses by both the T helper and T cytolytic compartment were markedly reduced as compared with transgene-negative littermates, and no evidence could be found for islet infiltrates. Adoptive transfer of histocompatible lymphocytes from transgene-negative mice plus virus into irradiated Ins-HA hosts resulted in islet inflammation dominated by CD4+ T cells, indicating that the HA antigen was accessible to activated T cells. These results suggest that T cells can be rendered tolerant of antigens expressed outside the thymus.     

A randomized trial of a program to reduce the use of psychoactive drugs in nursing homes.

BACKGROUND. Although psychoactive medications have substantial side effects in the elderly, these drugs are used frequently in nursing homes. Few interventions have succeeded in changing this situation, and little is known about the clinical effects of such interventions. METHODS. We studied six matched pairs of nursing homes; at one randomly selected nursing home in each pair, physicians, nurses, and aides participated in an educational program in geriatric psychopharmacology. At base line we determined the type and quantity of drugs received by all residents (n = 823), and a blinded observer performed standardized clinical assessments of the residents who were taking psychoactive medications. After the five-month program, drug use and patient status were reassessed. RESULTS. Scores on an index of psychoactive-drug use, measuring both the magnitude and the probable inappropriateness of medication use, declined significantly more in the nursing homes in which the program was carried out (experimental nursing homes) than in the control nursing homes (decrease, 27 percent vs. 8 percent; P = 0.02). The use of antipsychotic drugs was discontinued in more residents in the experimental nursing homes than in the control nursing homes (32 percent vs. 14 percent); the comparable figures for the discontinuation of long-acting benzodiazepines were 20 percent vs. 9 percent, and for antihistamine hypnotics, 45 percent vs. 21 percent. In the experimental nursing homes residents who were initially taking antipsychotic drugs showed less deterioration on several measures of cognitive function than similar residents in the control facilities, but they were more likely to report depression. Those who were initially taking benzodiazepines or antihistamine hypnotic agents reported less anxiety than controls but had more loss of memory. Most other measures of clinical status remained unchanged in both groups. CONCLUSIONS. An educational program targeted to physicians, nurses, and aides can reduce the use of psychoactive drugs in nursing homes without adversely affecting the overall behavior and level of functioning of the residents.