Psychoneuroendocrinology of anxiety disorders

This article focuses on neuroendocrine measures in anxiety disorders and their relationships to neurotransmitter and neuroendocrine function. In particular, the hypothalamic-pituitary-somatotropin and the hypothalamic-pituitary-adrenal (HPA) axes are emphasized, and a role for extrahypothalamic corticotropin releasing factor is proposed. Additional neuroactive hormones are also considered. A nonhuman primate model of anxiety is discussed in terms of its neuroendocrine relevance. And, throughout, a hypothetical functional-anatomic model for anxiety and panic is proposed using the findings of cognitive neuroscience fear research. Finally, an effort is made to synthesize existing psychoneuroendocrinologic data into a current conceptualization of the pathophysiology of anxiety disorders.     

Anterior-posterior patterning within the Caenorhabditis elegans endoderm

The endoderm of higher organisms is extensively patterned along the anterior/posterior axis. Although the endoderm (gut or E lineage) of the nematode Caenorhabditis elegans appears to be a simple uniform tube, cells in the anterior gut show several molecular and anatomical differences from cells in the posterior gut. In particular, the gut esterase ges-1 gene, which is normally expressed in all cells of the endoderm, is expressed only in the anterior-most gut cells when certain sequences in the ges-1 promoter are deleted. Using such a deleted ges-1 transgene as a biochemical marker of differentiation, we have investigated the basis of anterior-posterior gut patterning in C. elegans. Although homeotic genes are involved in endoderm patterning in other organisms, we show that anterior gut markers are expressed normally in C. elegans embryos lacking genes of the homeotic cluster. Although signalling from the mesoderm is involved in endoderm patterning in other organisms, we show that ablation of all non-gut blastomeres from the C. elegans embryo does not affect anterior gut marker expression; furthermore, ectopic guts produced by genetic transformation express anterior gut markers generally in the expected location and in the expected number of cells. We conclude that anterior gut fate requires no specific cell-cell contact but rather is produced autonomously within the E lineage. Cytochalasin D blocking experiments fully support this conclusion. Finally, the HMG protein POP-1, a downstream component of the Wnt signalling pathway, has recently been shown to be important in many anterior/posterior fate decisions during C. elegans embryogenesis (Lin, R., Hill, R. J. and Priess, J. R. (1998) Cell 92, 229-239). When RNA-mediated interference is used to eliminate pop-1 function from the embryo, gut is still produced but anterior gut marker expression is abolished. We suggest that the C. elegans endoderm is patterned by elements of the Wnt/pop-1 signalling pathway acting autonomously within the E lineage.     

Expression of the third component of complement, C3, in regenerating limb blastema cells of urodeles

In this study we have shown that complement component C3 is expressed in the regenerating tissue during urodele limb regeneration. C3 was expressed in the dedifferentiated regeneration blastema and in the redifferentiated limb tissues in the axolotl, Amblystoma mexicanum, and in Notophthalmus viridescens. This expression was verified by immunofluorescent staining using an Ab against axolotl C3 and by in situ hybridization with an axolotl C3 cDNA probe. In the early stages of regeneration C3 appeared to be equally present in all mesenchymal cells and in the wound epithelium, whereas in the later stages it was mainly expressed in the differentiating muscle cells. Since no expression was seen in the developing limb, it appears that the C3 expression was specific to the regeneration process. We then demonstrated by hybridization experiments that a blastema cell line of myogenic origin expresses C3. All these findings implicate C3 in the dedifferentiation process and may indicate a new role for this molecule in muscle differentiation.     

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors increase fibrinolytic activity in rat aortic endothelial cells. Role of geranylgeranylation and Rho proteins

Lipid and lipoprotein disorders are frequently detected in insulin dependent diabetics, which predisposes the high cardiovascular risk present in these patients. Studies performed with insulin dependent children showed early changes in lipid metabolism, usually correlated and aggravated by poor glycemic control. However, there are abnormalities present even in diabetic children with good glycemic control. The usual measures used to improve diabetic control are not sufficient to correct all the lipid disorders in Diabetes Mellitus. Hyperglycemia is the major factor, inducing metabolic lipid changes by increasing hepatic synthesis of triglycerides and promoting lipoprotein and apolipoprotein glycosylation and oxidation. Other changes, associated with the decrease of lipoprotein lipase activity are directly related to insulin deficiency. The lipid profile in children with poor diabetic control is similar to that already described for adult patients. The main abnormalities found are: increased levels of triglycerides, VLDL-Tg, LDL-Tg, VLDL-Cholesterol, Apo B and Apo CIII, with decreased values of HDL-Cholesterol and Apo AI. As there is a strong correlation between control and the degree of lipid changes, even with normal levels of cholesterol and triglycerides, measurements of Apo AI, Apo B100 and Apo CIII seem to be good and reliable indicators of glycemic control in diabetic children, and a factor with high predictive value for the evaluation of cardiovascular risk in adult patients.     

Thrombolysis for stroke

The fate of 89 patients with meningomyelocele operated at the Institute of Orthopedics and Rehabilitation in Poznań between 1970 and 1989 due to paretic deformities of lower extremities has been traced by the authors. Deformities prevented nursing, standing or ambulating; their type and results of treatment have been related to the level of neurosegmental lesion. Modified Sharrard's classification served to group the patients. The level of lesion established during lower extremities muscles testing has been verified after neurological examination supplemented with electrophysiological tests: sensory response within L3-S2 dermatomes, afferent conduction velocity of the peroneal nerve and selected muscles of lower extremity electromyogram. Deformities due to inadequate nursing (hip and knee contractures and equinus foot) were the main obstacle in the rehabilitation in patients with spinal Th12-L2 lesion. In patients with L3-L5 lesion hip contractures were accompanied by dislocation or subluxation of the hip due to muscular imbalance. Knee contracture was less frequent in this group and foot deformities were diverse. Surgical correction of paretic deformity of the hip was the last stage of management designed to promote rehabilitation, following previous foot and knee surgery. In patients with Th12-L2 lesion recurrence of contractures made standing and walking impossible. In patients with L3-L5 neurosegmental lesion surgery for paretic dislocation or subluxation of the hip inclusive of open reduction, varus-derotation osteotomy of the proximal femur, transiliac osteotomy and iliopsoas transfer to the greater trochanter according to Mustard resulted in stable hip. Seventy percent of patients with L3-L4 lesion and all patients with L5 lesion profited from hip surgery with reduced orthotic use and effective gait.     

The development and cross-validation of methods based on radioimmunoassay and LC/MS-MS for the quantification of the class III antiarrhythmic agent, MK-0499, in human plasma and urine

An analytical method based on radioimmunoassay (RIA) has been developed for the determination of the antiarrhythmic agent, MK-0499, in plasma and urine. Owing to the potency of the drug, the specificity of this assay in human plasma could not be adequately determined using conventional RIA procedures. A highly specific procedure, based on LC/MS-MS, was developed to cross-validate the RIA. The lower quantifiable limits of the RIA and LC/MS-MS-based methods were 0.05 and 0.013 ng ml-1, respectively. Cross-validation data, compared using paired student's t-test regression analysis, showed excellent correlation between methods. The mass spectrometric assay was also used to simultaneously measure plasma concentrations of unlabeled and 14C-labeled MK-0499 following administration of the drug at high specific activity to volunteers.     

Gbeta subunit interacts with a peptide encoding region 956-982 of adenylyl cyclase 2. Cross-linking of the peptide to free Gbetagamma but not the heterotrimer

The region encoded by amino acids 956-982 of adenylyl cyclase 2 is important for Gbetagamma stimulation. Interactions of a peptide encoding the 956-982 region of adenylyl cyclase 2 (QEHAQEPERQYMHIGTMVEFAYALVGK (QEHA peptide)) with Gbetagamma subunits were studied. QEHA peptide was covalently attached to beta subunit of free Gbetagamma by the cross-linker N-succinimidyl(4-iodoacetyl)aminobenzoate. Cross-linking was proportional to the amount of QEHA peptide added; other control peptides cross-linked minimally. When Go was used, very little cross-linking was observed with GDP and EDTA, but upon activation by guanosine 5'-3-O-(thio)triphosphate and Mg2+, specific cross-linking of the QEHA peptide to Gbeta was observed. We conclude that beta subunits of G proteins contain effector interaction domains that are occluded by Galpha subunits in the heterotrimer. Molecular modeling studies used to dock the QEHA peptide on to Gbeta indicate that amino acids 75-165 of Gbeta may be involved in effector interactions.