肾上腺素对促肾上腺皮质激素分泌的影响及其作用机制的初步探讨

对颈外静脉预先置入硅橡胶导管的大鼠注射肾上腺素,应用放射免疫测定法,直接测定血浆促肾上腺皮质激素(ACTH)浓度的改变,以了解肾上腺素影响肾上腺皮质活动的机理。实验在脑内正中隆起损伤和假损伤两组动物中进行,结果外周给肾上腺素兴奋垂体前叶释放ACTH,从而兴奋肾上腺皮质的活动;作用点在下丘脑,兴奋促肾上腺皮质激素释放激素(CRF)的分泌,而非直接作用于腺垂体.     

Adrenal masses: characterization with T1-weighted MR imaging

The ability of a T1-weighted spin-echo magnetic resonance (MR) sequence to allow differentiation of benign from malignant adrenal masses at 0.5 T was investigated in 28 patients with 35 adrenal masses. All nine lesions with an adrenal mass-liver signal intensity ratio of 0.71 or less were metastases, and all 15 with a ratio of 0.78 or more were adenomas. Eleven masses (31%)--including six adenomas, three metastases, a pheochromocytoma, and a neuroblastoma--had ratios between these values. Nine of ten masses with adrenal mass-fat intensity ratios of 0.35 or less were metastases, and all 12 with ratios of 0.42 or more were benign. Eleven masses (31%), four malignant and one benign, had ratios between these values. The ratios for two masses could not be calculated due to lack of fat. The specificity of T1-weighted MR imaging in differentiating benign from malignant adrenal masses appears similar to that reported for T2-weighted imaging. However, significant overlap occurred, as has also been reported for T2-weighted imaging. While both imaging sequences may help distinguish benign from malignant adrenal masses in some cases, biopsy is still necessary when an accurate histologic diagnosis is essential.     

Perceived control over condom use among sex workers in Madagascar: a cohort study

Background  

Women's perceived control over condom use has been found to be an important determinant of actual condom use in some studies. However, many existing analyses used cross-sectional data and little quantitative information exists to characterize the relationships between perceived control and actual condom use among sex worker populations.     

The clandestine uterus: or how the uterus escapes detection prior to puberty

Uterine agenesis is one of the differential diagnoses in adolescent girls with delayed menstruation. It may also be suspected earlier in childhood during investigations for other genitourinary conditions. However, accurate confirmation that the uterus is absent can be extremely difficult before puberty because of its small size. We describe ten girls referred to a specialist centre with a presumed diagnosis of an absent uterus which was later found to be incorrect. We conclude that imaging should be undertaken by clinicians with experience in management of this age group and in some girls it may be necessary to delay final diagnosis until after puberty.     

Methods for analyzing referral patterns

OBJECTIVE: To develop a sound method to identify patient and physician characteristics that influence specialty referrals. DESIGN: A retrospective cohort analysis of medical claims data from 1996 supplemented with surveys of primary care physicians. SETTING: A 600-member independent practice association in southeastern Michigan that provided care for 90,000 members of an HMO. PATIENTS: Five cohorts, each of 2,000 to 6,000 patients with diagnoses that could be referred to cardiologists, ophthalmologists, pulmonologists, orthopedists, or general surgeons. MAIN RESULTS: The referral rates for the different cohorts ranged from 1% to 7%. The discriminatory ability of the multivariate logistic models (c-statistic) ranged from 0.66 to 0.79. The likelihood of referral was associated with the patient's diagnoses and medications and with the referring physician's age, years out of medical school, satisfaction with the specialty being referred to, and the importance of making or confirming a diagnosis. CONCLUSIONS: Because these methods were not difficult to implement and the results were credible, we believe that other organizations should be able to use them.     

Abdominal compartment syndrome caused by tension pneumoperitoneum in a scuba diver

Abdominal compartment syndrome is a surgical emergency caused by a raised intra-abdominal pressure, which may lead to respiratory, cardiovascular and renal compromise. It is most commonly seen in post-operative and trauma patients and it has a variety of causes. Tension pneumoperitoneum (TP) is a rare cause of abdominal compartment syndrome most often seen after gastrointestinal endoscopy with perforation.We present the case of a fit 52-year-old experienced female diver who developed TP and shock following a routine training dive to 27m. Following accidental inhalation of water, she had an unstaged ascent and, on reaching the surface, developed severe acute abdominal pain and distension. She was brought to our emergency department by air ambulance for assessment. Clinical and radiological examination revealed a shocked patient with dramatic free intra-abdominal gas and signs of abdominal compartment syndrome, which was treated with needle decompression. Symptoms and signs resolved quickly with no need for further surgical intervention. TP is a surgical emergency where surgery can be avoided with prompt diagnosis and treatment.