Jane E. Dahlstrom

Accelerated Maturation and Abnormal Morphology in the Preterm Neonatal Kidney

Nephrogenesis is ongoing at the time of birth for the majority of preterm infants, but whether postnatal renal development follows a similar trajectory to normal in utero growth is unknown. Here, we examined tissue collected at autopsy from 28 kidneys from preterm neonates, whose postnatal survival ranged from 2 to 68 days, including 6 that had restricted intrauterine growth. In addition, we examined kidneys from 32 still-born gestational controls. We assessed the width of the nephrogenic zone, number of glomerular generations, cross-sectional area of the renal corpuscle, and glomerular maturity and morphology. Renal maturation accelerated after preterm birth, with an increased number of glomerular generations and a decreased width of the nephrogenic zone in the kidneys of preterm neonates. Of particular concern, compared with gestational controls, preterm kidneys had a greater percentage of morphologically abnormal glomeruli and a significantly larger cross-sectional area of the renal corpuscle, suggestive of renal hyperfiltration. These observations suggest that the preterm kidney may have fewer functional nephrons, thereby increasing vulnerability to impaired renal function in both the early postnatal period and later in life.

Age-related pseudocapillarization of the human liver.

Age‐related changes in liver function are important because they may promote susceptibility to adverse drug reactions, neurotoxicity, atherosclerosis, and other important diseases in older people. Age‐related changes in the rat hepatic sinusoidal endothelium, termed pseudocapillarization, have been described recently and these may contribute to hepatic impairment. The present study has examined surgical and post‐mortem specimens with immunohistochemistry and transmission electron microscopy to determine whether pseudocapillarization also occurs in older humans. The age of the subject, independent of systemic disease or hepatic pathology in surgical and post‐mortem samples of human liver, was associated with increased peri‐sinusoidal expression of von Willebrands factor, collagen I, collagen IV, and staining with Massons trichrome. Electron microscopy revealed significant age‐related thickening of the sinusoidal endothelium (young 165 ± 17 nm, middle age 222 ± 11 nm, older 289 ± 9 nm, p < 0.001) with loss of fenestrations (young 7.7 ± 0.7 per 10 µm, middle age 3.6 ± 0.5 per 10 µm, older 1.5 ± 0.4 per 10 µm, p < 0.001), and age‐related deposition of basal lamina and collagen. In conclusion, ageing in humans is associated with morphological changes in the sinusoidal endothelium and space of Disse which are presumptively related to the ageing process and potentially represent an important link between the ageing process and disease susceptibility. Copyright

Altered decidual DC-SIGN+ antigen-presenting cells and impaired regulatory T-cell induction in preeclampsia.

Regulatory T (Treg) cell expansion is required for tolerance of the semi-allogeneic fetus in healthy pregnancy and impaired in preeclampsia in humans. However, the reasons remain unknown. Herein, we show that expansion of CD4(+)Helios(-)Foxp3(+) adaptive Treg (iTreg) cells, rather than CD4(+)Helios(+)Foxp3(+) natural Treg cells, accounts for this expansion in healthy pregnancy. This expansion is even more pronounced in the decidua, where there is an overrepresentation of iTreg cells. In preeclampsia, however, there is impaired systemic iTreg cell expansion, associated with a lack of iTreg cell overrepresentation in the decidua. Because decidual antigen-presenting cells (APCs) may be important for iTreg cell induction, we studied decidual CD14(+) APCs using immunohistochemistry and flow cytometry. We show that decidual CD14(+)DC-SIGN(+) APCs are closely associated with Foxp3(+) Treg cells. Furthermore, CD14(+)DC-SIGN(+) cells display a distinct phenotype compared with their CD14(+)DC-SIGN(-) counterparts. In particular, they have increased expression of tolerogenic molecules, HLA-G, and immunoglobulin-like transcript 4. In vitro, CD14(+)DC-SIGN(+) APCs from healthy pregnant women induced iTreg cells significantly more efficiently than CD14(+)DC-SIGN(-) APCs. Conversely, in preeclampsia, both CD14(+)DC-SIGN(+) and CD14(+)DC-SIGN(-) APCs induced iTreg cells poorly. These results suggest that decidual CD14(+)DC-SIGN(+) APCs may play important roles in iTreg cell induction, a process that is defective in preeclampsia and likely contributes to its pathogenesis.

Immunohistochemistry of Omega Class Glutathione S-Transferase in Human Tissues

Omega class glutathione transferase (GSTO) has been recently described in a number of mammalian species. We used immunohistochemistry to determine the cellular and tissue distribution of GSTO1–1 in humans. Expression of GSTO1–1 was abundant in a wide range of normal tissues, particularly liver, macrophages, glial cells, and endocrine cells. We also found nuclear staining in several types of cells, including glial cells, myoepithelial cells of the breast, neuroendocrine cells of colon, fetal myocytes, hepatocytes, biliary epithelium, ductal epithelium of the pancreas, Hoffbauer cells of the placenta, and follicular and C-cells of the thyroid. These observations and the known activity of GSTO1–1 suggest biological functions that are not shared with other GSTs. (J Histochem Cytochem 49:983–987, 2001)

Chorioamnionitis/funisitis and the development of bronchopulmonary dysplasia

Objective:  To examine the association between chorioamnionitis with or without funisitis and bronchopulmonary dysplasia in infants less than 30 completed weeks gestation given the current standards of antenatal steroid and surfactant use.

Mice Deficient in Glutathione Transferase Zeta/Maleylacetoacetate Isomerase Exhibit a Range of Pathological Changes and Elevated Expression of Alpha, Mu, and Pi Class Glutathione Transferases

Glutathione transferase zeta (GSTZ1-1) is the major enzyme that catalyzes the metabolism of alpha-halo acids such as dichloroacetic acid, a carcinogenic contaminant of chlorinated water. GSTZ1-1 is identical with maleylacetoacetate isomerase, which catalyzes the penultimate step in the catabolic pathways for phenylalanine and tyrosine. In this study we have deleted the Gstz1 gene in BALB/c mice and characterized their phenotype. Gstz1(-/-) mice do not have demonstrable activity with maleylacetone and alpha-halo acid substrates, and other GSTs do not compensate for the loss of this enzyme. When fed a standard diet, the GSTZ1-1-deficient mice showed enlarged liver and kidneys as well as splenic atrophy. Light and electron microscopic examination revealed multifocal hepatitis and ultrastructural changes in the kidney. The addition of 3% (w/v) phenylalanine to the drinking water was lethal for young mice (<28 days old) and caused liver necrosis, macrovesicular steatosis, splenic atrophy, and a significant loss of circulating leukocytes in older surviving mice. GSTZ1-1-deficient mice showed constitutive induction of alpha, mu, and pi class GSTs as well as NAD(P)H:quinone oxidoreductase 1. The overall response is consistent with the chronic accumulation of a toxic metabolite(s). We detected the accumulation of succinylacetone in the serum of deficient mice but cannot exclude the possibility that maleylacetoacetate and maleylacetone may also accumulate.

What motivates senior clinicians to teach medical students

BackgroundThis study was designed to assess the motivations of senior medical clinicians to teach medical students. This understanding could improve the recruitment and retention of important clinical teachers.MethodsThe study group was 101 senior medical clinicians registered on a teaching list for a medical school teaching hospital (The Canberra Hospital, ACT, Australia). Their motivations to teach medical students were assessed applying Q methodology.ResultsOf the 75 participants, 18 (24%) were female and 57 (76%) were male. The age distribution was as follows: 30–40 years = 16 participants (21.3%), 41–55 years = 46 participants (61.3%) and >55 years = 13 participants (17.3%). Most participants (n = 48, 64%) were staff specialists and 27 (36%) were visiting medical officers. Half of the participants were internists (n = 39, 52%), 12 (16%) were surgeons, and 24 (32%) were other sub-specialists. Of the 26 senior clinicians that did not participate, two were women; 15 were visiting medical officers and 11 were staff specialists; 16 were internists, 9 were surgeons and there was one other sub-specialist. The majority of these non-participating clinicians fell in the 41–55 year age group. The participating clinicians were moderately homogenous in their responses. Factor analysis produced 4 factors: one summarising positive motivations for teaching and three capturing impediments for teaching. The main factors influencing motivation to teach medical students were intrinsic issues such as altruism, intellectual satisfaction, personal skills and truth seeking. The reasons for not teaching included no strong involvement in course design, a heavy clinical load or feeling it was a waste of time.ConclusionThis study provides some insights into factors that may be utilised in the design of teaching programs that meet teacher motivations and ultimately enhance the effectiveness of the medical teaching workforce.

Spitz Naevus: Diagnostic Problems And Their Management Implications.

Spitz naevus is an uncommon, benign melanocytic neoplasm that shares many clinical and histological features with melanoma. While Spitz naevi typically occur in children and melanomas typically occur in adults, either tumour can occur in a patient of any age. In cases displaying all or most of the classical histological features, particularly when occurring in a young patient, it is possible to make a confident diagnosis of Spitz naevus. However, for those lesions with atypical features it may be difficult to predict the biological behaviour with certainty from the histopathological appearance. Hence, such tumours have been referred to by a variety of names including atypical Spitz naevus, atypical Spitz tumour and spitzoid tumours of uncertain malignant potential. However, even acknowledged experts in dermatopathology have a low concordance in distinguishing Spitz naevus with atypical features from melanoma. In this article, we highlight the histopathological features of Spitz naevi and those that may be useful in distinguishing Spitz naevi from melanomas. A suggested practical guide to clinical management of such lesions is provided.

Fatty acids alter glycerolipid metabolism and induce lipid droplet formation, syncytialisation and cytokine production in human trophoblasts with minimal glucose effect or interaction

The diabetic pregnancy is characterized by maternal hyperglycaemia and dyslipidaemia, such that placental trophoblast cells are exposed to both. The objective was to determine the effects of hyperglycaemia, elevated non-esterified fatty acids (NEFA) and their interactions on trophoblast cell metabolism and function. Trophoblasts were isolated from normal term human placentas and established in culture for 16 h prior to experiments. Glucose utilisation, fatty acid oxidation and fatty acid esterification were determined using radiolabelled metabolic tracer methodology at various glucose and NEFA concentrations. Trophoblast lipid droplet formation including adipophilin mRNA expression, viability, apoptosis, syncytialisation, secretion of hormones and pro-inflammatory cytokines were also assessed. Glucose utilisation via glycolysis was near maximal at the low physiological glucose concentration of 4mM; whereas NEFA esterification into triacylglycerol and diacylglycerol increased linearly with increasing NEFA concentrations without evidence of plateau. Culture of trophoblasts in 0.25 mM NEFA for 24h upregulated fatty acid esterification processes, inhibited fatty acid oxidation, inhibited glycerol release (a marker of lipolysis) and promoted adipophilin and lipid droplet formation, all consistent with upregulation of fatty acid storage and buffering capacity. NEFA also promoted trophoblast syncytialisation and TNFalpha, IL-1beta, IL-6 and IL-10 production without effects on cell viability, apoptosis or hormone secretion. Hyperglycaemia caused intracellular glycogen accumulation and reduced lipid droplet formation, but had no other effects on trophoblast metabolism or function. NEFA have effects on trophoblast metabolism and function, mostly independent of glucose, that may have protective as well as pathophysiological roles in pregnancies complicated by diabetes and/or obesity.

Antenatal steroids may reduce adverse neurological outcome following chorioamnionitis: Neurodevelopmental outcome and chorioamnionitis in premature infants

Objective:  To examine the effect of antenatal steroid exposure and in utero inflammation on the development of severe intraventricular haemorrhage, periventricular leukomalacia and long‐term neurological outcome in infants less than 30 completed weeks gestation.