Prolactin receptor-mediated activation of pSTAT5 in the pregnant mouse brain.

Pregnancy represents a period of remarkable adaptive physiology throughout the body, with many of these important adaptations mediated by changes in gene transcription in the brain. A marked activation of the transcription factor signal transducer and activator of transcription 5 (STAT5) has been described in the brain during pregnancy and likely drives some of these changes. We aimed to investigate the physiological mechanism causing this increase in phosphorylated STAT5 (pSTAT5) during pregnancy. In various tissues, STAT5 is known to be activated by a number of different cytokines, including erythropoietin, growth hormone and prolactin. Because the lactogenic hormones that act through the prolactin receptor (PRLR), prolactin and its closely-related placental analogue placental lactogen, are significantly increased during pregnancy, we hypothesised that this receptor was primarily responsible for the pregnancy-induced increase in pSTAT5 in the brain. By examining temporal changes in plasma prolactin levels and the pattern of pSTAT5 immunoreactivity in the hypothalamus during early pregnancy, we found that the level of pSTAT5 was sensitive to circulating levels of endogenous prolactin. Using a transgenic model to conditionally delete PRLRs from forebrain neurones (Prlrlox/lox /CamK-Cre), we assessed the relative contribution of the PRLR to the up-regulation of pSTAT5 in the brain of pregnant mice. In the absence of PRLRs on most forebrain neurones, a significant reduction in pSTAT5 was observed throughout the hypothalamus and amygdala in late pregnancy, confirming that PRLR is key in mediating this response. The exception to this was the hypothalamic paraventricular nucleus, where only 17% of pSTAT5 immunoreactivity during pregnancy was in PRLR-expressing cells. Taken together, these data indicate that, although there are region-specific mechanisms involved, lactogenic activity through the PRLR is the primary signal activating STAT5 in the brain during pregnancy.

Management of excess weight in pregnancy in Otago, New Zealand: a qualitative study with lead maternity carers.

AIM: To investigate the knowledge and practice of midwives providing lead maternity care (LMC) in Otago, regarding gestational weight gain (GWG). METHODS: A qualitative study was conducted using three semi-structured focus groups and one in-depth interview. A total of 12 midwives, including one student midwife, were interviewed. Transcripts were analysed using generic coding and thematic analysis. At the conclusion of the focus groups no new themes were emerging. RESULTS: Themes discussed included midwives' knowledge of GWG, methods used to identify BMI and weight gain throughout pregnancy, current management, barriers to management and tools used to overcome these barriers. There was satisfactory knowledge of the risks associated with excess GWG, however, adherence to current New Zealand guidelines and awareness of international guidelines in this area was limited. Management of GWG was highly varied and the weighing of pregnant women was not common practice. Sensitivity around the topic of weight management was identified as a major barrier to care. CONCLUSIONS: The management inconsistencies highlighted in this study have identified a need for New Zealand guidelines for the management of GWG. Clear guidelines along with increased education and collaboration between health professionals would help alleviate the current uncertainty regarding weight management in pregnancy.

Vertebral levels of key landmarks in the neck.

Vertebral levels of key landmarks in the neck are well documented in anatomy texts but are they accurate? This study aimed to investigate the vertebral levels of the hard palate, hyoid bone, thyroid cartilage, cricoid cartilage, and bifurcation of the common carotid artery (CCA) using computed tomography (CT). After excluding patients with distorting pathology, 52 CT scans of the neck from supine adults with a standardized head position (mean age 63 ± 17 years, range 30-94 years; 21 female) were available for analysis by dual consensus reporting. Only the vertebral level of the hard palate (C1) was consistent with contemporary descriptions. Other landmarks were located most frequently at the following vertebral levels: the center of the body of the hyoid bone at C4 (54% of cases); the superior limit of the laminae of the thyroid cartilage at C4 in women (60%) and C5 in men (52%) (P = 0.02); the inferior border of the cricoid cartilage in the midline anteriorly at C6 in women (37%) and C7 in men (47%) (P = 0.008); and the bifurcation of the left and right common carotid arteries at C3 (left 56%, right 62%). The bifurcation of the CCA was a mean of 1.6 ± 1.2 cm above the superior border of the thyroid laminae. Vertebral levels of key bony/cartilaginous structures in the neck differ from standard descriptions but in the absence of a standardized cervical axial plane have limited value and clinical utility.

Anatomical planes: are we teaching accurate surface anatomy?

Anatomical planes used in clinical practice and teaching anatomy are largely derived from cadaver studies. Numerous inconsistencies in clinically important surface markings exist between and within anatomical reference texts. The aim of this study was to reassess the accuracy of common anatomical planes in vivo using computed tomographic (CT) imaging. CT scans of the trunk in supine adults at end tidal inspiration were analyzed by dual consensus reporting to determine the anatomy of five anatomical planes: sternal angle, transpyloric, subcostal, supracristal, and the plane of the pubic crest. Patients with kyphosis, scoliosis, or abnormal lordosis, distorting space-occupying lesions, or visceromegaly were excluded. Among 153 thoracic CT scans (mean age 63 years, 53% female), the sternal angle was most common at T4 (females) or T4/5 (males) vertebral level, and the tracheal bifurcation, aortic arch, and pulmonary trunk were most often below this plane. In 108 abdominal CT scans (mean age 60 years, 59% female), the subcostal and supracristal planes were most often at L2 (58%) and L4 (69%), respectively. In 52 thoracoabdominal CT scans (mean age 61 years, 56% female), the transpyloric plane was between lower L1 and upper L2 (75%); in this plane were the superior mesenteric artery (56%), formation of the portal vein (53%), tip of the ninth rib (60%), and the left renal hilum (54%), but the right renal hilum and gallbladder fundus were more often below. The surface anatomy of anatomical planes needs revising in the light of results from living subjects using modern imaging techniques.