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Phyllis W Sharps Ayman A E El-Mohandes M Nabil El-Khorazaty Michele Kiely Tessa Walker 《Journal of perinatology》2003,23(5):414-419
OBJECTIVE: To describe breastfeeding initiation among 210 urban African-American mothers with inadequate prenatal care. METHODS: This study is a case-control study of postpartum mothers recruited from four large urban hospitals. RESULTS: Mothers who chose to breastfeed were more educated, employed before birth, married, and using contraception postnatally. Regression model analysis controlling for demographic differences revealed that breastfeeding was significantly associated with a higher perception of severity of illness and higher confidence in the ability of health care to prevent illness. Breastfeeding mothers were less likely to reverse parent-child roles and had a lower perception of hassle from their infant's behavior. When comparing mothers who breastfed longer than 8 weeks to those who did not breastfeed, breastfeeding mothers had high scores related to empathy toward infants on the Adult-Adolescent Parenting Inventory as well as a low perception of hassle on the Parenting Daily Hassle. The perception of existing formal or informal social support did not influence breastfeeding behavior. CONCLUSION: Personal attributes of low-income urban mothers such as health beliefs and parental attitudes may play a role in the initiation and duration of breastfeeding. Low-income African-American mothers may be influenced in their choice to breastfeed by supportive messages from physicians and nurses delivering care to mothers and their newborns. Emphasis should be placed on the role breastfeeding can play in preventing childhood illnesses. 相似文献
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D N Louis S M Meehan R J Ferrante E T Hedley-Whyte 《Journal of neuropathology and experimental neurology》1992,51(2):150-157
Because the distinction between gliosis and low-grade astrocytoma may prove difficult by routine light microscopy, we evaluated the silver nucleolar organizer region (AgNOR) technique in making this distinction. The AgNOR impregnation was performed on formalin-fixed, paraffin-embedded tissue from 49 central nervous system (CNS) biopsies: eight normal brain, 14 gliosis, 14 grade 2 astrocytoma (Daumas-Duport scale), two grade 4 astrocytoma, nine medulloblastoma, one metastatic carcinoma, and one choroid plexus papilloma. Quantitative and qualitative differences were found between gliosis and low-grade astrocytomas. In gliosis, AgNOR counts averaged 1.18 +/- 0.11 (SD) AgNOR/nucleus, while in low-grade astrocytomas AgNOR counts averaged 2.22 +/- 0.39 (p less than 0.001). Compound AgNOR were frequent in 9/14 grade 2 astrocytomas and in both grade 4 astrocytomas, whereas compound AgNOR were extremely rare in cases of gliosis. Quantitative and qualitative differences were also found between normal cerebellar internal granular cells and medulloblastoma cells. Cerebellar granular cells averaged 0.90 +/- 0.10 AgNOR/nucleus whereas medulloblastoma cells had an average of 4.52 +/- 0.95 (p less than 0.001). Compound AgNOR were seen in all medulloblastomas but not in internal granular cells. These findings suggest that the AgNOR technique may be a useful adjunct in the diagnosis of CNS neoplasia. 相似文献
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1. The sensitivity to acetylcholine (ACh) of the fast posterior latissimus dorsi (PLD) and slow anterior latissimus dorsi (ALD) during embryonic development was studied and compared. The sensitivities were expressed as a ratio of the maximal tetanic tension and tension developed in response to ACh. 2. Up to the 17th day of incubation both muscles are sensitive to ACh to a similar extent; at the 18th day the sensitivity of the PLD muscle decreases and continues to do so until hatching and thereafter. 3. Since the decrease in sensitivity of PLD muscles takes place a few days after innervation, it is suggested that this is caused by activity of the motor nerve. To test this curare (dTc) and hemicholinium (HC-3), drugs that interfere with neuromuscular transmission, were injected into the yolk sac of the embryos when nervemuscle connections are usually established. In the curare and HC-3 treated embryos the desensitization of the PLD muscles did not take place. 4. The distribution of endplates on PLD muscles from drug treated 20-21 day old embryos was compared to that of untreated controls. Whereas control PLD muscles have only one band of endplates, muscles from curarized embryos and HC-3 treated embryos have several bands of endplates, and many muscle fibres with multiple innervation were found. 5. It is suggested that nerve fibres which make connections with PLD muscle fibres bring about a decline in chemosensitivity by releasing more transmitter, and thereby prevent further nerve muscle connections from being made along the same muscle fibre. 相似文献
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Coexpression of galanin and adrenocorticotropic hormone in human pituitary and pituitary adenomas.
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D. W. Hsu S. C. Hooi E. T. Hedley-Whyte R. M. Strauss L. M. Kaplan 《The American journal of pathology》1991,138(4):897-909
Galanin is a neuropeptide that regulates the secretion of several pituitary hormones, including prolactin (PRL) and growth hormone (GH). Galaninlike immunoreactivity (Gal-IR) and galanin mRNA in the rat anterior pituitary is cell lineage specific, with predominant expression in lactotrophs and somatotrophs. The authors examined the cellular distribution of human Gal-IR in seven normal postmortem pituitaries and 62 pituitary tumors by immunoperoxidase staining. In contrast to the rat, Gal-IR in human anterior pituitaries was present in corticotrophs scattered throughout the gland, but not in lactotrophs, somatotrophs, thyrotrophs, or gonadotrophs. Distinct Gal-IR also was present in hyperplastic and neoplastic corticotrophs in 19 of 22 patients with Cushing's disease. In noncorticotroph cell tumors, unequivocal Gal-IR was present in 5 of 11 GH-secreting tumors associated with clinical acromegaly, 9 of 18 nonfunctioning pituitary adenomas, and 2 of 14 prolactinomas. Of these galanin-positive tumors, four of the five GH-secreting adenomas, six of the nine nonfunctioning adenomas, and both of the prolactinomas also contained adrenocorticotropic hormone immunoreactivity (ACTH-IR). Immunostaining and in situ hybridization on adjacent sections using an 35S-labeled probe complementary to human galanin mRNA demonstrated predominant galanin expression in normal corticotrophs. Immunoelectron microscopy confirmed the presence of Gal-IR in pituitary cells characteristic of corticotrophs in both normal and neoplastic pituitaries. Thus, as in the rat, galanin gene expression in the human pituitary is cell-type specific. Unlike the rat, however, human galanin gene expression is restricted to the corticotroph lineage. Studies of tumors confirmed the observed coexpression of galanin and adrenocorticotropic hormone. The divergent cell type specificity of galanin production in human and rat pituitaries reflects different patterns of gene activation in these two species. In addition, these results suggest that galanin in the human pituitary may participate locally in the regulation of the hypothalamic-pituitary-adrenal axis. 相似文献
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Dejan Popovic Tessa Gordon Victor F. Rafuse Dr. Arthur Prochazka 《Annals of biomedical engineering》1991,19(3):303-316
Implanted wire electrodes are increasingly being used for the functional electrical stimulation of muscles in partially paralysed
patients, yet many of their basic characteristics are poorly understood. In this study we investigated the selectivity, recruitment
characteristics and range of control of several types of electrode in triceps surae and plantaris muscles of anaesthetized
cats. We found that nerve cuffs are more efficient and selective (i.e., cause less stimulus spread to surrounding muscles)
than intramuscular electrodes. Bipolar intramuscular stimulation was more efficient and selective than monopolar stimulation,
but only if the nerve entry point was between the electrodes. Monopolar electrodes are efficient and selective if located
close to the nerve entry point, but their performance declines with distance from it. Nonetheless, for a variety of reasons
monopolar stimulation provides the best compromise in many current applications. Short duration pulses offer the best efficiency
(least charge per pulse to elicit force) but high peak currents, increasing the risk of electrode corrosion and tissue damage.
Electrode size has little effect on recruitment and should therefore be maximised because this minimises current density. 相似文献
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