若干莽草酸衍生物的合成和生物活性研究

虽然对莽草酸(shikimic acid)的研究由来已久,但只是在陆续发现了具有生物活性的乙二醛酶Ⅰ抑制剂(glyoxalase Ⅰinhibitor 1)和二(口恶)霉素(dioxolamycin 2)等含莽草酸类母核的天然产物后,才有合成莽草酸衍生物进行生物活性研究的报道,即由莽草酸甲酯合成乙二醛酶Ⅰ抑制剂的类似物3。     

The association between retinal ischaemia and end-stage renal damage in thrombotic microangiopathy

Haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are conditions in which thrombocytopenia and microangiopathic haemolytic anaemia are associated with organ damage due to thrombotic microangiopathy (TMA). The prognosis for adults with HUS is variable, with some patients presenting with an acute illness from which a full recovery is made, whilst others develop irreversible renal failure. Evidence of retinal ischaemia was noted on presentation in a normotensive patient with irreversible renal failure due to HUS. This study examined prospectively the optic fundi of all patients who subsequently presented to a single adult renal unit (catchment population approximately 700,000) with HUS. Eleven patients presented with HUS over 12 years (1985-1997). Six patients with irreversible renal failure had retinal abnormalities either at the time or within a few days of initial presentation. The other five patients whose renal function recovered did not develop retinal changes during the course of their illness. Retinal ischaemia associated with TMA is a poor prognostic sign in adults with HUS.      

Factors Associated with Forgone Care Among Children in the United States: An Analysis of the 2016-2018 National Survey of Children’s Health

Delaying or forgoing health care can have negative consequences for the health and well-being of children. In 2000, Paul Newacheck called for the continued monitoring of unmet health needs among children. While a handful of studies have been conducted since 2000, primarily among children with special healthcare needs (CSHCN), the redesigned National Survey of Children’s Health (NSCH) offers a unique opportunity to examine forgone care among all children ages 0-17. This study provides the most recent prevalence estimates of forgone care among children in the United States, by type of care, and identifies related sociodemographic and health factors. We used data from the combined 2016-2018 NSCH to examine sociodemographic and health factors associated with parent/caregiver-reported forgone care among children ages 0-17 years in the United States. We also examined the association of these factors with different types of forgone care and reasons for forgone care. Survey weighted bivariate and logistic regression analyses were conducted. 101,984 children ages 0-17 years. 3.1% of children (2.2 million) had forgone care in 2016-2018. Forgone dental care was most frequently reported (1.67%), followed by medical care (1.03%) and mental health care (0.83%). Cost was the most frequently reported reason for forgone care (1.83%), followed by problems getting an appointment (1.20%) and lack of eligibility (0.97%). Children, who were older, had greater number of health conditions, were CSHCN, were Hispanic or non-Hispanic black, were uninsured, and had family incomes < 100% of the federal poverty level (FPL) were significantly more likely to have any reported forgone care. Among children with forgone care, the factors associated with reporting different types of forgone care varied. After adjustment, insurance status was the only factor consistently associated with all types of care, except hearing services; CSHCN status, number of health conditions, and insurance status were associated with forgone dental care; race/ethnicity and insurance were associated with forgone vision care; age, number of health conditions, CSHCN status, and insurance were associated with forgone mental care; and FPL was associated with forgone hearing services. The factors associated with the different reasons for forgone care also varied. Insurance status and FPL were associated with forgone care due to lack of eligibility and issues with cost; CSHCN status was associated with services not available in the area; and insurance, CSHCN status, and race/ethnicity were associated with problems getting an appointment. Forgone care remains an issue for over 2.2 million children in the United States. However, the characteristics of children associated with different types of forgone care vary, as do those associated with different reasons for forgoing care. This suggests the need for diverse strategies, in addition to standing efforts to expand insurance coverage, to ensure timely access to needed healthcare services among US children. Efforts to reduce forgone care will need to address both financial and nonfinancial issues and will need to be tailored to address the factors associated with forgoing different types of care.     

Juvenile polyposis in a tropical country

The clinical profile, malignant potential, and management of 17 children with juvenile polyposis (more than five juvenile polyps) were evaluated clinically and endoscopically. Colonoscopy and polypectomy were done three weekly until colonic clearance was achieved, and thereafter two yearly. All polyps were subjected to histological examination. Mean age was 7.7 years, with a male preponderance (3:1). Presentation was with rectal bleeding (94%), pallor (65%), stunted growth (53%), and oedema (47%), and the mean (SD) duration of symptoms was 33 (27) months. None had a positive family history or any congenital anomaly. Two children had six polyps up to the transverse colon; the rest had numerous polyps all over the colon. All children had juvenile polyps on histology and 10 (59%) had adenomatous changes (dysplasia). Total colectomy was done in six for intractable symptoms. Colon clearance was achieved in eight after an average 3.4 polypectomy sessions, and three were still on the polypectomy programme. In conclusion, juvenile polyposis is commonly associated with low grade dysplasia. Serial colonoscopic polypectomy is effective but colectomy is required for intractable symptoms and when clearance of the colon is not possible.     

Cardiovascular effects of carbon dioxide in ventilated preterm infants

Sick preterm infants may, under certain conditions, demonstrate blood pressure passive cerebral blood flow in response to changes in arterial carbon dioxide tension. Blood pressure in turn depends on cardiac output and peripheral resistance. A Doppler technique for assessing cardiac output compared favourably in terms of reproducibility to a thermodilution technique in a group of infants undergoing cardiac catheterization for congenital heart disease. Doppler was subsequently used to monitor changes in cardiac output following an increase in arterial carbon dioxide tension of 1 kPa in 25 ventilated preterm infants. Blood pressure increased significantly (p = 0.006). However, heart rate did not change significantly (p = 0.16) and, in addition, both stroke and minute volume decreased (p = 0.023, p = 0.02, respectively). This suggests that accompanying changes in components of peripheral resistance exert important effects on blood pressure in the preterm neonate in response to changes in arterial carbon dioxide tension.