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131.
Human infants are particularly responsive to olfactory cues emanating from their mother's nipple/areola region. Beginning within minutes after birth, maternal breast odors elicit preferential head orientation by neonates and help guide them to the nipple. Such odors also influence babies' general motor activity and arousal, which may contribute further to successful nipple localization and sucking. The role of maternal olfactory signals in the mediation of early breast-feeding is functionally analogous to that of nipple-search pheromone as described in nonhuman mammals. To some extent, the chemical profile of breast secretions overlaps with that of amniotic fluid. Therefore, early postnatal attraction to odors associated with the nipple/areola may reflect prenatal exposure and familiarization. Although newborns are generally attracted to breast odors produced by lactating women, breast-fed infants rapidly learn their mother's characteristic olfactory signature while sucking at her breasts and can subsequently recognize her by that unique scent alone. Early odor-based recognition may be an important factor in the development of the infant-mother bond.  相似文献   
132.
A study of brain lipids in patients with the sphingomyelinase-deficient types of Niemann-Pick disease demonstrated that abnormal accumulation of sphingomyelin occurs only in the brain of neuronopathic type A patients but not in the non-neuronopathic type B. Additional lipid abnormalities were present in the type A brain. In contrast, the brain lipid profile was normal in type B patients. Since lysosphingolipids have been implicated in the biochemical pathogenesis of other genetic lysosomal sphingolipidoses, the occurrence of sphingosylphosphorylcholine (lysosphingomyelin) was specifically investigated in brain and extraneural tissues, using an HPLC method with fluorescent detection of orthophtalaldehyde derivatives. Levels close to or below the limit of detection (10 pmol/mg tissue protein) were observed in normal and pathological controls. A striking accumulation was observed in brain of two Niemann-Pick type A patients (830 and 430 pmol/mg protein in 27-and 16-month-old children with severe and milder neurological course, respectively), which was not present at the fetal stage of the disease. No significant increase was found in brain tissue from a 3.5 year-old type B patient. In liver and spleen, abnormally high sphingosylphosphorylcholine levels were observed in both types of the disease, with indication of a progressive increase during development. This study establishes the integrity of brain tissue in Niemann-Pick disease type B and suggests that the lysocompound sphingosylphosphorylcholine could play a role in the pathophysiology of brain dysfunction in the neuronopathic type A.  相似文献   
133.
We evaluated ethanol- and HCl-induced mucosal damages in developing rats. The degree of damage induced by ethanol and HCl was greatest in 1-week-old rats and decreased significantly with age until 4 weeks; thereafter it increased again. To evaluate the effect of weaning on the maturational changes in mucosal defense, we compared ethanol-induced mucosal damage among three groups of newborn rats: (1) receiving milk only; (2) receiving only rat chow from 14 days of age, and (3) having free access to milk and chow. There were no significant differences at 18 and 21 days of age. The mucus thickness increased with age until 8 weeks and was not affected by weaning. In conclusion, developmental changes occur in gastric mucosal protection in rats. Weaning does not have a significant effect on these changes.  相似文献   
134.
OBJECTIVE: The occipitotranstentorial approach is well accepted for lesions of the pineal region, superior cerebellar vermis, or mesencephalon. Although evidently suitable, this approach has not, to our knowledge, been reported for lesions of the superior cerebellar hemisphere in adults. Experience with this approach is reported. METHODS: Four patients underwent surgery between August 1995 and March 1997. The findings obtained are evaluated. RESULTS: All lesions were situated in the quadrangular lobules (one extending into the vermis), and all were completely removed. Postoperative deficits, especially visual field deficits, did not occur. CONCLUSION: Lesions of the superior cerebellar hemispheres are easily approached by an occipitotranstentorial route. The major advantages over a supracerebellar approach are that the surgical route is nearly perpendicular to the lesion and to the tentorium instead of parallel, and wide exposure is thereby possible.  相似文献   
135.
136.
Dorsal fusion with the internal fixator has become the standard treatment of instabilities and deformities of the thoracolumbar spine. With our new device, the modular spine fixator (MSF), which has been specially designed for short-distance instrumentations, we have increasingly been treating unstable injuries of the thoracolumbar spine by one-level stabilization. Prerequisite is an accurate evaluation of the indication, including CT and MRI to assess the involvement of the intervertebral disc and the ligamental structures. The operative technique differs in some details from the procedure in more-multi-level instrumentations, especially concerning the application of the pedicle screws. The instrumentation is always combined with posterior allogenic bone grafting. Since the beginning of 1993 we also perform anterior autogenic transpedicular bone grafting. Between January 1991 and July 1995, 57 one-level stabilizations with the MSF were performed. Of the 57 patients operated on 39, 27 men and 12 women, with an average age of 41 years, have had a clinical and radiographic follow-up examination so far, on average, 27 months after the accident. Seventeen patients were completely free of pain and 17 patients (were only) sensitive to weather changes or had minor pain during great physical stress. Five patients had pain even during slight physical stress or at rest. The preoperatively measured Cobb angle was 15.1 degrees on average, after the operation 5.2 degrees, and at the time of the follow-up examination amounted to 8.1 degrees. The patients' range of motion was normal. Only five minor complications have been seen. No implant fatigue failure has been noted in this series. We derive from these results that, for correct indications, one-level stabilization can be performed successfully and should be firmly established in the operative treatment of unstable fractures of the thoracolumbar spine.  相似文献   
137.
We have studied mechanisms by which leptin overexpression, which reduces body weight via anorexic and thermogenic actions, induces triglyceride depletion in adipocytes and nonadipocytes. Here we show that leptin alters in pancreatic islets the mRNA of the genes encoding enzymes of free fatty acid metabolism and uncoupling protein-2 (UCP-2). In animals infused with a recombinant adenovirus containing the leptin cDNA, the levels of mRNAs encoding enzymes of mitochondrial and peroxisomal oxidation rose 2- to 3-fold, whereas mRNA encoding an enzyme of esterification declined in islets from hyperleptinemic rats. Islet UCP-2 mRNA rose 6-fold. All in vivo changes occurred in vitro in normal islets cultured with recombinant leptin, indicating direct extraneural effects. Leptin overexpression increased UCP-2 mRNA by more than 10-fold in epididymal, retroperitoneal, and subcutaneous fat tissue of normal, but not of leptin-receptor-defective obese rats. By directly regulating the expression of enzymes of free fatty acid metabolism and of UCP-2, leptin controls intracellular triglyceride content of certain nonadipocytes, as well as adipocytes.  相似文献   
138.
FITC (fluorescein isothiocyanate)-labeled albumin was used as a substrate to further characterize the digestion of host blood proteins by adult Haemonchus contortus. Isolated H. contortus intestine degraded FITC-albumin; degradation was completely inhibited by E-64, a specific inhibitor of cysteine proteases. The in vitro uptake and degradation of FITC-albumin by parasites was also evaluated. Uptake of fluorescence was demonstrated; greater than 50% of the fluorescence was associated with degraded FITC-albumin. However, both the uptake and degradation of FITC-albumin were reduced by about 85%. Additionally, when parasites were incubated in the presence of specific inhibitors of cysteine proteases, degradation of FITC-albumin was shown to occur rapidly in the media during in vitro incubation. This degradation was blocked completely by the presence of cysteine protease inhibitors. These results indicate that the rapid extracorporeal digestion of FITC-albumin (mediated by secreted cysteine proteases) produce relatively high concentrations of low molecular weight FITC-labeled fragments and alters the kinetics of uptake of fluorescence by the parasite. These fragments rather than FITC-albumin are rapidly taken up by the parasites. Thus in vitro demonstration of a definitive role for the cysteine proteases as intestinal digestive enzymes in H. contortus is compromised by the enzyme's extracorporeal activity. This extracorporeal cysteine protease activity may represent the enzyme's predominant activity.  相似文献   
139.
PURPOSE: To examine the association between communication with parents and self-harm in 14-19-year-old adolescents. METHODS: A total of 36 female and 16 male adolescents presenting to the accident and emergency department of a general hospital; 52 hospital-based controls were interviewed and studied using the following scales: Parent-Adolescent Communication Scale, Family Adaptability and Cohesion Evaluation Scale, Adolescent-Family Inventory of Life Events and Changes Scale, Children's Depression Index, and Nowicki-Strickland Locus of Control Scale. RESULTS: The absence of a family confidant was very strongly associated with adolescent self-harm. Despite controlling for a wide range of possible causal factors, poorer parent-adolescent communication remained strongly associated with self-harm. The effect of poorer communication on self-harm was strongest in the group with and internal locus of control. CONCLUSIONS: Impairment of communication between adolescents and their parents may be important in the origins of adolescent self-harm.  相似文献   
140.
A 6-yr-old boy presented with muscle weakness, lactic acidemia, and insulin-dependent diabetes mellitus (IDDM). Using PCR and restriction enzyme analysis, he was found to have the classical A3248G mitochondrial DNA (mtDNA) mutation frequently associated with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). The mutation was confirmed by sequencing muscle mtDNA. The mutation in mtDNA from muscle, lymphoblasts, and blood was clearly demonstrable by standard methods using ethidium bromide staining. His mother also had IDDM, but no A3243G mutation could be detected in her blood or transformed lymphoblasts using the same PCR technique. When PCR was carried out in the presence of [32P]deoxycytidine triphosphate, subsequent autoradiography detected the presence of the mutation at low levels in mtDNA from the mother's lymphoblasts and blood. Study of the mother's muscle showed a mitochondrial myopathy, despite the fact that she was asymptomatic. We emphasize that the increased sensitivity of radiolabeled PCR may be necessary to detect small percentages of heteroplasmic A3243G mtDNA mutation in blood from diabetic subjects. Otherwise the incidence of mtDNA mutations in both IDDM and non-insulin dependent diabetes may be underestimated.  相似文献   
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