Substrate-affinity relationship of succinate dehydrogenase in brain of albino rat during dieldrin toxicity

Substrate kinetics of succinate dehydrogenase (EC 1.3.99.1) were studied in the brain of control and dieldrin-treated albino rats. Dieldrin inhibited the enzyme activity to various degrees and also altered the Michaelis-Menten constant (Km) of the enzyme. Activation energy values (delta E) were increased, suggesting decreased maximal velocity Vmax, and the high Km obtained for the enzyme also revealed decreased enzyme-substrate affinity and masking of active sites by dieldrin.     

Effects of a 4-week freshwater fish (trout) diet on platelet aggregation, platelet fatty acids, serum lipids, and coagulation factors

Eight healthy subjects consumed a diet in which all animal products were replaced by 750 g/day of freshwater trout. Platelet eicosapentaenoic acid (EPA) as a percentage of total platelet fatty acids rose from a prediet level of 0.2 +/- 0.4% to 3.4 +/- 1.6% after 4 weeks on the diet. Platelet arachidonic acid remained unchanged. Platelets became more hyperaggregable to collagen (p less than .025) but became hypoaggregable to arachidonic acid (p less than .05). The Ivy bleeding time became prolonged rising from a mean of 148 seconds before the diet to 168 seconds at 2 weeks and 202 seconds at 4 weeks. Serum lipids, coagulation profiles, and blood pressure remained unchanged. The changes induced by this diet were much less marked than changes induced by marine fish diets and diets supplemented by marine fish oil extracts, despite the fact that an equivalent amount of EPA was consumed and incorporated into platelets. These findings suggest that other substances, in addition to n-3 unsaturated fatty acids, may be responsible for the antithrombotic properties of marine fish.     

Family physicians are an important source of newborn care: the case of the state of Maine

Family physicians (FPs) provided 30 percent of inpatient newborn care in Maine in the year 2000. FPs cared for a large proportion of newborns, especially those insured by Medicaid and in smaller, rural hospitals where FPs also delivered babies. Family medicine's commitment to serve vulnerable populations of newborns requires continued federal, state, and institutional support for training and development of future FPs.     

Family physicians make a substantial contribution to maternity care: the case of the state of Maine

Family physicians provided nearly 20 percent of labor and delivery care in Maine in the year 2000. A substantial proportion of this care was provided to women insured by Medicaid and those delivering in smaller, rural hospitals and residency-affiliated hospitals. As family medicine explores its future scope, research identifying regional variations in the maternity care workforce may clarify the need for maternity care training in residency and labor and delivery services in practice.     

Oncocytic mucoepidermoid carcinoma: clinicopathologic description in a series of 12 cases

Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. Oncocytic MEC (OMEC) has been rarely reported with previous cases suggesting they are largely cystic low-grade neoplasms with a favorable prognosis. The differential diagnosis of OMEC includes numerous oncocytic/"oncocytoid" neoplasms. Some are benign while others are aggressive. Recent evidence suggests that p63 is a reliable marker in the diagnosis of conventional MEC but has not been explored in OMEC. We searched the archives of various institutions for examples of OMEC to re-appraise the grade, and to evaluate p63 immunohistochemistry as a tool to separate OMEC from its potential mimics. A total of 12 cases were identified. There were 6 males and 6 females with an age range of 30 to 79 years. Most occurred in the parotid (9) with 1 each in the sublingual gland, hard palate and neck. They showed minimal cystic content and were infiltrative and solid tumors spanning all grades. All tumors had focal mucin production and were composed almost exclusively of oncocytic cells with 2 cases demonstrating conventional MEC areas. All 6 cases tested showed the majority of oncocytic cells staining with p63 in a diffuse pattern, demonstrating its utility in the diagnosis of OMEC. Of the 6 cases with follow-up information, 1 case had local recurrence 8 years after the initial surgery. Three cases showed skin or bone invasion. None had lymph node/distant metastases. In summary, OMEC behaves as a low-grade tumor, and is diffusely positive for p63, which may aid in its differential diagnosis.     

Intraductal Pancreatic Neuroendocrine Tumor

Intraductal lesions of the pancreas are usually due to intraductal papillary mucinous neoplasms and the less common intraductal tubular adenoma. Cases of acinar cell carcinoma within intraductal location have also been encountered recently. Pancreatic neuroendocrine tumors are rarely encountered within the main pancreatic duct. A 74-year-old male presented with non-specific abdominal symptoms and was found to have an obstructive lesion in the main pancreatic duct with associated chronic pancreatitis. A distal pancreatectomy was performed which revealed a solid and cystic tumor measuring 6 × 3 × 2 cm situated wholly within the main pancreatic duct. It formed an obstructing intraluminal polypoid lesion that resulted in surrounding chronic pancreatitis. Microscopic evaluation of the mass showed it to be a well-differentiated pancreatic neuroendocrine tumor with entrapped, non-malignant tubules. Intraductal pancreatic neuroendocrine tumors may occur in two settings. Firstly, and more commonly, there is a parenchymal-based tumor that then encroaches on and pushes into the main pancreatic duct. The less common scenario is of a primary intraductal location without a pancreatic parenchymal lesion. While an intraductal location of a pancreatic neuroendocrine tumor is rare, it should be borne in mind when confronted by an intraductal lesion in the pancreas.