健康教育防制儿童营养性贫血的可行性研究

本文以大规模随机化人群实验,用铁剂治疗、铁剂预防和空白对照的方法论证了健康教育做为儿童营养性贫血防制对策与措施的可行性.结果证实健康教育与药物治疗相比前者具有受益人群广泛、发挥作用长效、预防病种广谱、投入少效益高和人群依从性好等优点,比传统的药物治疗和预防更有推广价值,对儿童营养性贫血和类似的儿童常见病的防制是经济、有效的措施.特别是对大规模的人群实施干预只有健康教育是可行的.在预防和治疗疾病过程中也应转变唯药物有效的观念,重视心理和行为的作用,对健康教育给予应有的重视.     

Geometric Resistance and Microvascular Network Architecture of Human Colorectal Carcinoma

Objective : To measure the geometric resistance to blood flow in human colorectal carcinoma. Although tumor blood flow is of central importance in both the detection and the treatment of cancer, the determinants of blood flow through the neoplastic circulation are poorly understood. Methods : Human colorectal carcinomas (tissue weight = 272 g ± 43 g (SD), n = 6) were perfused ex vivo with a buffered physiological salt solution of known viscosity at flow rates ranging from 2.5 to 40 ml/min and perfusion pressures from 8 to 100 mm Hg. The geometric resistance was determined from the slope of the pressure-flow curve. For examination of the principal determinant of geometric resistance, the vascular architecture, one of the tumors was perfused with Batson's No. 17 polymer and macerated in KOH to produce a positive vascular cast that was used for measurement of vascular branching patterns and dimensions. Results : The pressure-flow relationship was linear at perfusion pressures above 40 mm Hg, and the geometric resistance, z₀, was constant at approximately 6.5 ± 10⁹g/cm³. Below 40 mm Hg, z₀ increased rapidly. The architecture of the arteriolar and capillary networks of human colorectal carcinoma is similar to those of experimental rodent tumors. Capillaries in planar and nonplanar mesh-works had mean segment diameters of 11 ± 2 and 9.6 ± 2 μm, lengths of 46 ± 24 and 107 ± 40 μm, and intercapillary distances of 46 ± 13 and 74 ± 24 μm, respectively. Conclusions : The geometric flow resistance in neoplastic tissue is 1–2 orders of magnitude higher than that observed in normal tissues. A decrease in functional vascular cross-sectional area may explain the additional increase in resistance at small perfusion pressures. The observed flow resistance may be due to the specialized arteriolar and capillary network architecture, pressures exerted by proliferating cancer cells, and/or coupling between vascular and extravascular flow. These observations demonstrate that tumor vascularity alone may not be indicative of flow resistance or tumor susceptibility to blood-borne therapeutic agents.     

Acute vascular rejection is associated with up-regulation of vitronectin receptor (alphavbeta3), increased expression of tissue factor, and activation of the extracellular matrix metalloproteinase induction system.

BACKGROUND: A cascade of inflammatory reactions characterize acute vascular rejection after heart transplantation. This study was undertaken to test the hypothesis that acute vascular rejection is associated with up-regulation of vitronectin receptor (alphavbeta3), increased expression of tissue factor, and activation of the extracellular matrix metalloproteinase induction system. METHODS: Acute vascular rejection developed in 14 heart transplant recipients within 2 weeks of transplantation, confirmed by immunofluorescence (AVR group). We compared these patients with 10 transplant recipients who had no evidence of acute vascular rejection or peritransplant ischemic injury (control group). We evaluated endomyocardial biopsy specimens for alphavbeta3, tissue factor, and extracellular matrix metalloproteinase inducer (EMMPRIN). RESULTS: Compared with the control group, the AVR group demonstrated evidence of significantly increased expression of alphavbeta3 (1.9-fold, p < 0.001), tissue factor (1.8-fold, p < 0.001), and EMMPRIN (1.5-fold, p < 0.001). All patients in the AVR group received plasmapheresis; 11 of 14 patients had evidence of ischemic necrosis on biopsy specimens, and 3 of 14 patients experienced hemodynamic compromise and graft dysfunction and died within 3 weeks of transplant. Another patient died at 10 months after transplant. CONCLUSIONS: Acute vascular rejection is associated with up-regulation of alphavbeta3, tissue factor, and activation of the matrix metalloproteinase induction system, which may contribute to the lethal morbidity associated with this disease.     

MR imaging of pineal cysts

Identification of pineal cysts with imaging modalities other than magnetic resonance (MR) has been infrequent, despite a reported autopsy incidence of as high a 40%. We recently identified 15 patients in whom pineal cysts were seen on MR. These cysts ranged from 5 to 15 mm in maximum diameter. The cyst walls were thin, usually measuring less than 2 mm. The signal characteristics of the fluid within the cysts paralleled that of CSF, although it differed somewhat in signal intensity from CSF collections in which there was pulsatile motion. All lesions were midline in location. There was no significant mass effect, although mild flattening of the superior colliculi could be seen. Two cases were operated on; at operation, typical pineal cysts were found, with one containing hemosiderin-laden proteinaceous material, which accounted for its markedly higher signal intensity. It is important that this entity be recognized so that these lesions are not confused with pineal tumors.     

Effect of electric and chemical stimulation of the raphe obscurus on phrenic nerve activity in the cat

The effect of electrical and chemical (l-glutamate) stimulation of the raphe obscurus on phrenic nerve activity was examined in the cat. Phrenic nerve activity was recorded from a C5 nerve root in anesthetized, paralyzed and artificially ventilated cats. Neural discharge was quantitated by integrating the phrenic nerve activity. The respiratory frequency was determined from the integrated nerve signal. Focal electrical stimulation (18–144 μA; 5–40 Hz; 100 μs pulse duration) resulted in significant (P < 0.05) increases in both integrated phrenic nerve (IPN) amplitude and respiratory frequency. These changes were dependent upon current intensity and frequency of stimulation. The largest increases in IPN amplitude and respiratory frequency were47 ± 17%and146 ± 8%, respectively. To insure that the changes in integrated phrenic nerve activity (IPNA) were the result of stimulation of cell bodies and not axons of passage,l-glutamate (100, 200 nmol) was microinjected (100 nl) into the raphe obscurus. Significant (P < 0.05) dose-related changes occurred in integrated phrenic nerve amplitude with an increase of44 ± 13% at 100 nmol and80 ± 13% at 200 nmoll-glutamate. No significant increase in respiratory frequency was observed withl-glutamate microinjection. The results suggest that the raphe obscurus may be involved in respiratory control.     

Central nervous system site of action for the hypotensive effect of clonidine in the cat

The purpose of our study was to determine whether clonidine exerts its centrally mediated hypotensive action at three sites that influence arterial pressure located in the medulla, specifically associated with the intermediate area of the ventrolateral medulla. The "intermediate area" lies approximately 1.5 mm caudal to the border of the trapezoid body (caudal border) and 4 mm lateral to the midline. One of the sites that influence arterial pressure lies in the nucleus reticularis rostroventrolateralis. The second site lies in close proximity to the rostral part of the nucleus reticularis lateralis (rLRN) and also near the A1 area. The third site lies in the most rostral area and medial to the nucleus reticularis rostroventrolateralis, that is in the nucleus paragigantocellularis lateralis. Unilateral microinjections of 0.22 and 0.43 nmol of clonidine into the rLRN produced dose-dependent decreases in arterial pressure. The 0.43 nmol dose of clonidine had no effect when unilaterally or bilaterally microinjected into either the nucleus reticularis rostroventrolateralis or into the nucleus paragigantocellularis lateralis. Microinjection of the alpha-2 adrenoceptor antagonist, idazoxan (16.6 nmol), unilaterally into rLRN had no effect per se, but prevented the hypotensive effect of a subsequent microinjection of clonidine. Similarly, bilateral microinjection of idazoxan into rLRN counteracted the hypotensive effect of i.v. administered clonidine. These data indicate that clonidine acts at alpha-2 adrenoceptors in the rLRN to produce hypotension.     

Clinical and microbiological effects of daily brushing with either NaF or SnF2 gels in subjects with fixed or removable dental prostheses

61 adults, with fixed or removable dental protheses, completed a 6-month double-blind trial comparing the clinical and microbial effects of brushing twice daily with either 0.22% NaF or 0.4% SnF2. Those subjects brushing with SnF2 had less gingivitis and fewer bleeding sites for both "total teeth" and "abutment teeth". Plaque scores between groups were only statistically different for the "abutment teeth". The microbial parameters, salivary S. mutans and subgingival plaque total CFU, were significantly reduced in the SnF2 group. In both treatment groups, there was a reduction over the course of the study in the number of subjects with recoverable A. actinomycetemcomitans and black pigmented bacteroides, yet there was no difference between groups.