Acute reversibility of pulmonary hypertension predicts neither long-term hemodynamic response nor outcome in patients awaiting heart transplantation

For transplant wait-list patients with end-stage congestive heart failure, reversibility of pulmonary hypertension tested with acute administration of vasodilators is a prerequisite to listing for transplantation. We have shown that the magnitude of the initial pulmonary vasodilatory response to nitroprusside predicts neither the extent of the long-term hemodynamic response nor the subsequent need for transplantation versus clinical improvement and removal from transplant consideration.     

Phonological codes are used in integrating information across saccades in word identification and reading.

A major issue in reading is the extent to which phonological information is used in visual word perception. The present experiments demonstrated that phonological information acquired on 1 fixation from a word in the parafovea is used to help identify that word when it is later fixated. A homophone of a target word, when presented as a preview in the parafovea, facilitated processing in the target word seen on the next fixation more than a preview of a word matched with the homophone in visual similarity to the target word. This facilitation was observed both in the time to name an isolated target word and in the fixation time on the target word while silently reading a sentence; the preview was virtually never consciously identified in either task. Because the visual similarity of the preview to the target also plays a part in the facilitative effect on the preview, however, codes other than phonological codes are preserved across saccades. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreased proportion of type I myofibers in skeletal muscle of dogs with chronic heart failure

BACKGROUND: Whether biochemical and histological abnormalities of skeletal muscle (SM) develop in patients with chronic heart failure (HF) remains controversial. In the present study, dogs with chronic HF were used to examine potential alterations of SM fiber type, fiber size, number of capillaries per fiber (C/F), beta-adrenergic receptor density (Bmax), and fiber ultrastructural integrity. METHODS AND RESULTS: HF was produced in 17 dogs by sequential intracoronary microembolizations. Biopsies of the lateral head of the triceps muscle were used in all studies. Type I and type II fibers were differentiated by myofibrillar ATPase (pH 9.4 or 4.2). Bmax was assessed by radioligand binding and SM ultrastructure by transmission electron microscopy. Comparisons were made with biopsies obtained from nine control dogs. The percentage of SM type I fibers was reduced in HF dogs compared with control dogs (19 +/- 2% versus 32 +/- 5%) (p < 0.001), whereas the percentage of SM type II fibers was increased (81 +/- 2% versus 68 +/- 5%) (p < 0.001). The change in fiber type composition was not associated with a preferential atrophy or hypertrophy of either fiber type. There was no difference in SM Bmax (198.9 +/- 14.3 versus 186.8 +/- 17.3 fmol/mg protein) or in C/F (5.37 +/- 0.26 versus 5.84 +/- 0.21) between HF dogs and control dogs. No ultrastructural abnormalities were present in SM fibers of HF dogs. CONCLUSIONS: In dogs with HF, there is a decrease in the relative composition of the slow-twitch type I SM fibers and an increase in fast-twitch type II fibers. The shift in fiber type composition is not associated with preferential atrophy of either fiber type or with a reduction in C/F, beta-adrenergic receptor density, or structural abnormalities of the myofibers.     

Human olfactory neuroepithelial cells: tyrosine phosphorylation and process extension are increased by the combination of IL-1beta, IL-6, NGF, and bFGF

Olfactory neuroepithelial cells (ONC) grown from biopsies of human donors are a novel cell culture system that may facilitate studies into normal and disease-related human neurobiology. We further characterized the expression of cell surface markers and intermediate filaments, and responses to neurotrophic factors by ONC. ONC are positive for cell surface markers N-CAM, PSA-N-CAM, neutral endopeptidase, N-aminopeptidase, NGF low-affinity receptor homologue (CD40), and transferrin receptor by flow cytometry for the intermediate filament proteins peripherin, vimentin, and NF-H by immunocytochemistry. Responses to neurotrophic factors measured were process outgrowth, cytoskeletal protein expression, and protein phosphorylation. Process outgrowth was increased by interleukin-beta 164-171 (IL-1beta) or by the combination of IL-1beta, interleukin-6 (IL-6), nerve growth factor (NGF), and basic fibroblast growth factor (bFGF). This combination of IL-1beta, IL-6, NGF, and bFGF (16NF) increased expression of two cytoskeletal proteins, NF-H protein and microtubule-associated protein tau. Application of the individual neurotrophic factors IL-1beta, IL-6, NGF, and bFGF increased protein phosphorylation, while 16NF produced an immediate increase in tyrosine phosphorylation of several proteins (MW of 40-80, 120, 150, and 190 kDa). The 16NF combination appears to act through a tyrosine-kinase-mediated pathway to induce process extension and increase NF-H expression. The ONC culture has the potential to be further explored to examine the relationship among process outgrowth, protein phosphorylation, and synergy between neurotrophin and cytokine receptor systems.     

Power Spectral Analysis of Heart Rate Varability in Sudden Cardiac Death: Comparison to Other Methods

Power spectrum analysis of heart rate variability is described and compared to four other reported methods, with respect to their efficacy as predictors of risk of sudden cardiac death (SCD). Approximate frequency domain representations were obtained for each. The underlying physiologic processes which may give rise to spectral components are considered. These methods were employed to analyze 24-h ambulatory ECG's of patient populations at different degrees of risk of SCD. Heart rate variability was found to be reduced in cardiac patients known to be at increased risk of SCD, when compared to those not at increased risk. These differences were greatest in power spectral methods. Thus, power spectrum analysis appears to be more effective than the other methods in segregating these populations, suggesting that this method may be useful in categorizing cardiac patients according to risk of sudden cardiac death.     

Cerebellar arachnoid cyst in a firesetter: the weight of organic lesions in arson

Disruption of synaptic activity of a number of cerebral structures (e.g., neostriatum, amygdala, and thalamus) produces marked deficits in retention of instrumentally conditioned behaviors. When animals are given a relatively high number of training trials or high intensities of footshock during learning, however, such disruption is considerably less effective. Since there is a close anatomical and functional relationship between the neostriatum and the substantia nigra, it was of interest to determine whether enhanced training with a high level of footshock would prevent the reported amnesic state induced by injections of GABA antagonists into the latter structure. Rats were trained in a one-trial inhibitory task, using 0.2 or 0.4 mA, and then injected with microgram quantities of picrotoxin or bicuculline into the substantia nigra and posterior region of the zona incerta; retention was measured 24 h later. Only those groups that had been injected into the nigra and trained with 0.2 mA showed amnesia. These results support the hypotheses that (a) the normal activity of a set of structures is essential for the development of memory consolidation and (b) after an enhanced learning experience these structures may participate in memory consolidation, but are not necessary for the occurrence of this process.     

Interaction effect of D4 dopamine receptor gene and serotonin transporter promoter polymorphism on the cortisol stress response.

Genetic variation of the serotonin transporter (SCL6A4, 5-HTT) has been associated with fear- and anxiety-related behaviors, while a polymorphism in exon III of the D4 dopamine receptor gene (DRD4) has been linked to novelty seeking. The dopaminergic and the serotonergic neurotransmitter system have been found to modulate the amygdala-connected circuitries that are crucial in emotional modulation and response to fearful stimuli. Additionally, reactivity of amygdala-innervated effector systems is also essential for our understanding of anxiety-related behaviors. Here, we used the stress-induced activation of the hypothalamic-pituitary-adrenal axis to investigate the impact of 5-HTTLPR and DRD4 on the cortisol stress response in 84 healthy adults. Saliva cortisol was measured during and after the Trier Social Stress Test. We found a significant main effect of DRD4: Carriers of the 7R allele exhibited lower cortisol responses. Additionally, a DRD4 by 5-HTTLPR interaction emerged: 5-HTTLPR LA/LA homozygotes showed a lower cortisol response than did S or LG allele carriers but only if they possessed at least one copy of the DRD4 7R allele. The results point to independent and joint effects of these polymorphisms on stress responsivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)