A model for predicting the transmission rate of malaria from serological data

A model is developed to estimate the duration for which malaria antibody levels in the blood remain high in a closed population. This estimate can be used to calculate the transmission rate within a region, in conjunction with the serological information contained in the population. The model is used on data obtained from a study of malaria in the Philippines and shows excellent agreement. It is subsequently utilised for predictions and seems to be an appropriate vehicle for this purpose.     

Smoking patterns and dependence: Contrasting chippers and heavy smokers.

The authors used ecological momentary assessment to contrast smoking patterns among chippers (CHs; n = 26)--smokers who smoke despite an apparent absence of tobacco dependence--with those seen in heavy smokers (HSs; n = 28). Smoking and nonsmoking settings (activity, mood, etc.) were assessed by means of electronic diary. CHs were not social smokers; like HSs, they smoked half their cigarettes while alone. When smoking, CHs' urge levels equaled those of HSs; between cigarettes, CHs had few urges, whereas HSs reported moderate urges. CHs' smoking was particularly associated with indulgent activities: relaxation, socializing, eating, and drinking alcohol. Outside of these indulgent settings, CHs' (but not HSs') smoking was associated with negative affect. In idiographic analyses, CHs' smoking was under much stronger stimulus control than was that of HSs. The authors propose that the disappearance of stimulus control over use is a characteristic of dependence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pure red cell aplasia in autoimmune polyglandular syndrome with T lymphocytosis

We report the onset of pure red cell aplasia (PRCA) in a patient with a history of polyglandular syndrome including Addison's disease, malabsorption syndrome, diabetes type I and gastric hyperplastic polyposis. An autoimmune origin for this complex disorder was not supported by the presence of organ specific antibodies, but T cells were found to be of polyclonal origin, as demonstrated by molecular analysis of T cell receptor (TCR) gene rearrangement. The pathophysiology of this case, based on laboratory findings and response to therapy, is discussed.     

Coexpression of erythroid and megakaryocytic genes in acute erythroblastic (FAB M6) and megakaryoblastic (FAB M7) leukaemias

There is evidence to suggest a close relationship between the erythroid and megakaryocytic lineages. Using RT-PCR, we evaluated the coexpression of erythroid and megakaryocytic genes in blasts from 25 acute myeloid leukaemia (AML) cases (FAB M1-M7) and three unclassifiable leukaemias with trilineage dysplasia (trilineal AML). All FAB M6 and M7 and trilineal leukaemias expressed mRNAs for alpha-globin, glycoprotein IIb (GpIIb), erythropoietin receptor (Epo-R) and thrombopoietin receptor (c-mpl), but not for myeloperoxidase (MPO) which in contrast was expressed in the other FAB-subtype leukaemias. These data support the hypothesis that blasts from M7 and M6 leukaemias may derive from (or represent) a common progenitor cell with resident bipotentiality towards the megakaryocytic and erythrocytic lineages.     

Immediate Antecedents of Cigarette Smoking: An Analysis of Unrestricted Smoking Patterns.

Theory suggests that cigarette smoking is under stimulus control and that affect is a key trigger for smoking. A previous study (S. Shiftman et al., 2002) showed little relationship between affect and smoking, but this relationship could have been suppressed by the impact of smoking restrictions. The study evaluated these associations in a 1988 sample that was subject to few smoking restrictions. Smokers (N = 28) not seeking treatment used palmtop computers to record context and affect prior to smoking (n = 2,217 observations) and also at random times when not smoking (n = 2,380). Comparisons showed little relationship between smoking and affect. Smoking was associated with particular activities and locations. Urge to smoke was the strongest predictor of smoking. The results replicated the findings of S. Shiffman et al. (2002). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strobe rearing prevents the convergence of inputs with different response timings onto area 17 simple cells

Strobe rearing prevents the convergence of inputs with different response timings onto area 17 simple cells. J. Neurophysiol. 80: 3005-3020, 1998. The preceding paper showed that the loss of direction selectivity in simple cells induced by strobe rearing reflects the elimination of spatially ordered response timing differences across the receptive field that underlie spatiotemporal (S-T) inseparability. Here we addressed whether these changes reflected an elimination of certain timings or an alteration in how timings were associated in single cells. Timing in receptive fields was measured using stationary bars undergoing sinusoidal luminance modulation at different temporal frequencies (0.5-6 Hz). For each bar position, response phase versus temporal frequency data were fit by a line to obtain two measures: absolute phase and latency. In normal cats, many individual simple cells display a wide range of timings; in layer 4, the mean range for absolute phase and latency was 0.21 cycles and 39 ms, respectively. Strobe rearing compressed the mean timing ranges in single cells, to 0.08 cycles and 31 ms, respectively, and this compression accounted for the loss of inseparability. A similar compression was measured in layer 6 cells. In contrast, the range of timing values across the simple-cell population was relatively normal. Single cells merely sampled narrower than normal regions of the timing space. We sought to understand these cortical changes in terms of how inputs from the lateral geniculate nucleus (LGN) may have been affected by strobe rearing. In normal cats, a wide range of absolute phase and latency values exists among lagged and nonlagged LGN cells, and these thalamic timings account for most of the cortical timings. Also, S-T inseparability in many simple cells can be attributed to the convergence of lagged and/or nonlagged inputs. Strobe rearing did not change the sampling of lagged and nonlagged cells, and the geniculate timings continued to account for most of the cortical timings. However, strobe rearing virtually eliminated cortical receptive fields with mixed lagged and nonlagged timing, and it compressed the timing range in cells dominated by one or the other geniculate type. Thus strobe rearing did not eliminate certain timings in LGN or cortex, but prevented the convergence of different timings on single cells. To account for these results, we propose a developmental model in which strobe stimulation alters the correlational structure of inputs based on their response timing. Only inputs with similar timing become associated on single cortical cells, and this produces S-T separable receptive fields that lack the ability to confer a preferred direction of motion.     

Menadione induces changes in the membrane electrical properties associated with downregulation of insulin receptors in human erythrocytes

BACKGROUND AND OBJECTIVE: To investigate the course of the intraocular pressure (IOP) in nonglaucomatous patients with pseudoexfoliation (PSX) syndrome after cataract surgery. PATIENTS AND METHODS: In a prospective age-matched controlled clinical study, 23 consecutive patients with PSX were studied and compared with a control group of 23 patients. The IOP was measured by applanation tonometry preoperatively, and postoperatively on day 1, after 4 weeks, and after 6 months. All patients were operated on with a self-sealing 7-mm scleral tunnel incision, phacoemulsification, and posterior chamber intraocular lens (IOL) implantation. RESULTS: Preoperatively the IOP was similar between both groups (P = .962). At the first postoperative day the IOP was below 22 mm Hg in all cases. After 4 weeks and 6 months a mean decrease of 3.88 mm Hg (P = .001) in the control group and of 3.15 mm Hg (P = .002) in the PSX group was observed; this difference was not statistically significant (P = .543). CONCLUSIONS: At 1 day postoperatively no pressure increase was observed in the eyes with PSX after scleral tunnel incision and phacoemulsification. Six months after cataract extraction with IOL implantation, the tension level decreased in the presence of PSX similarly as in normal eyes.     

Do resisted temptations during smoking cessation deplete or augment self-control resources?

A resource depletion model of self-control posits that for some period following performance of a task requiring self-control, self-control will be reduced and thus less available for use in a subsequent task. Using 2 substantial data sets collected in real time from individuals who were trying to quit smoking (1,660 and 9,516 temptation episodes collected from 61 and 248 individuals, respectively), we evaluated this model by testing the hypotheses that the number and length of resisted temptations and the intensity of the most recently reported urge during the prior 4 hr predict decreased self-control and increased likelihood of lapsing. Survival and multilevel regression modeling showed that contrary to the hypothesis, the number of recently resisted temptations predicted a lower risk of lapsing in both samples. Duration of resisted temptations had no significant effect in either sample. Intensity of most recently reported urge predicted lapsing in 1 data set but not in the other. Overall, there was little support for the resource depletion model. The protective effect of successfully resisting temptations was an unexpected but provocative finding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)