Pregnancy and development of diabetes in First Nations and non-First Nations women in Alberta, Canada.

AIM: To conduct a retrospective population-based study to examine the risk of developing diabetes after delivery in First Nations and non-First Nations women in Alberta. METHODS: Delivery records (1999-2014) were linked to provincial administrative data, which allowed for a maximum follow-up of 16 years after delivery. Prevalence of pregnancy risk factors were compared by First Nations status. Hazard ratios for diabetes after delivery by First Nations status, high pre-pregnancy body weight (≥91 kg) and gestational diabetes status were estimated using the Cox proportional hazards model. RESULTS: Age-adjusted prevalence of gestational diabetes (7.9% vs 4.6%; P<0.0001), high pre-pregnancy body weight (18.8% vs 10.2%; P<0.0001) and diabetes after delivery (3.9% vs 1.1%; P<0.0001) were higher in First Nations women than in non-First Nations women. Development of diabetes after delivery was higher with First Nations status (hazard ratio 3.0, 95% CI 2.6-3.4), high pre-pregnancy body weight (hazard ratio 3.6, 95% CI 3.3-4.0) and gestational diabetes status (hazard ratio 19.2, 95% CI 17.9-20.6). The highest risk was within First Nations women with high pre-pregnancy body weight and gestational diabetes (hazard ratio 54.8, 95% CI 45.2-66.5) compared to women without these three risk factors. Reduced prenatal visits per pregnancy (8.4 vs 10.7; P<0.0001) and delayed first prenatal visit (time to delivery 23.7 vs 26.7 weeks; P<0.0001) were observed in First Nations women compared to non-First Nations women. CONCLUSION: First Nations women are at greater risk of developing diabetes after pregnancy, with gestational diabetes being the strongest predictor. Strategies that target the specific needs of First Nations women before, during and after pregnancy are required.

Climate change is catchy--but when will it really hurt?

Concern and general awareness about the impacts of climate change in all sectors of the social-ecological-economic system is growing as a result of improved climate science products and information, as well as increased media coverage of the apparent manifestations of the phenomenon in our society. However, scales of climate variability and change, in space and time, are often confused and so attribution of impacts on various sectors, including the health sector, can be misunderstood and misrepresented. In this review, we assess the mechanistic links between climate and infectious diseases in particular, and consider how this relationship varies, and may vary according to different time scales, especially for aetiologically climate-linked diseases. While climate varies in the medium (inter-annual) time frame, this variability itself may be oscillating and/or trending on cyclical and long-term (climate change) scales because of regional and global scale climate phenomena such as the El-Nino southern oscillation coupled with global-warming drivers of climate change. As several studies have shown, quantifying and modelling these linkages and associations at appropriate time and space scales is both necessary and increasingly feasible with improved climate science products and better epidemiological data. The application of this approach is considered for South Africa, and the need for a more concerted effort in this regard is supported.

Autonomic nervous system dysfunction in obesity and Prader-Willi syndrome: current evidence and implications for future obesity therapies.

The autonomic nervous system (ANS) controls essential functions like breathing, heart rate, digestion, body temperature and hormone levels. Evidence suggests that ANS dysfunction is associated with adult and childhood obesity and plays a role in the distribution of total body fat and the development of obesity-related complications in humans. This review summarizes our current understanding of ANS involvement in the pathogenesis of obesity and Prader-Willi syndrome. Available evidence of ANS dysfunction in the control of energy balance is limited and, in some cases, contradictory. Further investigation in this area is warranted in order to better understand the important contributions of the ANS to regulation of body fat, development of obesity and its comorbidities. Results from these studies will guide the development of novel obesity therapeutics targeting specific ANS dysfunction.

A survey of enteric bacteria and protozoans in fresh bovine faeces on New Zealand dairy farms.

AIMS: To determine the counts and/or prevalence in fresh bovine faeces of Escherichia coli, enterococci, Campylobacter, Salmonella, shiga toxin-producing E. coli (STEC), Giardia and Cryptosporidium, as inputs to numerical models designed to estimate microbial loadings on pasture grazed by cattle in New Zealand. METHODS AND RESULTS: In each season over one year, samples of freshly deposited bovine faeces were collected from four New Zealand dairy farms (n = 155), and enumerated for E. coli, enterococci, Campylobacter, Giardia and Cryptosporidium. They were also tested for the presence of Salmonella and STEC. The overall median bacterial counts (g(-1) wet weight) were E. coli- 5.9 x 10(6); enterococci - 1.3 x 10(4); Campylobacter- 3.9 x 10(5). All counts were highly variable within and between samplings, and few seasonal or regional patterns emerged. However, mean Campylobacter counts were consistently higher in spring. No Salmonella spp. was detected, and only two samples were positive for STEC. Cryptosporidium and Giardia were isolated from 5.2% and 4.5% of the samples, respectively, yielding low numbers of (oo)cysts (1-25 g(-1) and 1-17 g(-1), respectively). CONCLUSIONS: Fresh bovine faeces are a significant source of E. coli, enterococci and Campylobacter on New Zealand pastures, although numbers are likely to vary markedly between faecal samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The study provides the first significant set of indicator and pathogen counts for one of the largest sources of faecal contamination of natural waters in New Zealand, and will be used to model these inputs.

Assessing the changing diet of indigenous peoples.

Because a dietary transition is occurring among indigenous populations from traditional foods to more market (store-bought) foods, there are concerns about a rise in diet-related chronic disease. More research into dietary intakes of indigenous peoples is needed. When the use of longitudinal studies is not possible, the use of cross-sectional data to characterize the process of dietary change appears to be an appropriate way to assess change during rapid transition.

The acardiac twin: a case report using color Doppler ultrasonography.

The use of color Doppler sonography has expanded our understanding of the normal and abnormal pregnancy. A case is presented here in which color Doppler imaging was utilized to confirm a long-held theory concerning the strikingly abnormal dynamics of arterial flow to an acardiac twin and observations are also presented concerning the possible route of venous return contrary to presumed theories established within the literature.

The vasa nervorum: microcorrosion casts for scanning electron microscopy.

Studies on the vasa nervorum have a long history, not least because of their beneficial application in surgical practice and in understanding the pathogenesis of some neuropathies. In the present study a method is described for the preparation of microcorrosion casts of the vasa nervorum suitable for examination by scanning electron microscopy. The results confirm the findings of earlier investigations but also demonstrate the advantages of an immediate three-dimensional representation of the vascular architecture together with the additional magnification and resolving power of electron microscopy.

The blood-nerve barrier: an in vivo lanthanum tracer study.

The permeability of the blood-nerve barrier was investigated using ionic lanthanum as an electron-dense tracer. The rat sural nerve was microinjected in vivo with lanthanum nitrate solution either into the endoneurial space or into the epineurium. Five to sixty minutes after injection the sural nerves were fixed by vascular perfusion or immersion. Using electron microscopy, lanthanum tracer was observed to be associated with endoneurial vessels in the perivascular spaces, in the inter-endothelial clefts and within the lumina. Furthermore, tracer was present in the spaces between adjacent endothelial cell layers and within vesicles and caveolae of endothelial cells. Epineurial vessels showed a similar distribution of tracer deposits but in greater quantities in inter-endothelial cell spaces and vessel lumina. The results are considered to demonstrate an absence of a blood-nerve barrier to ions as exemplified by lanthanum and are compatible with data from physiological experiments. The blood-nerve and blood-brain barriers are contrasted in their permeability to ions, their related fine structure and their physiological roles.

Filipin-sterol complexes at nodes of Ranvier.

Using the filipin-sterol technique, regional heterogeneity in the axonal and Schwann cell plasma membranes was investigated at the node of Ranvier and paranodes. Filipin-sterol complexes were abundant at the nodal axolemma but infrequent throughout the paranodal axolemma. The paranodal Schwann cell plasma membrane was rich in complexes which extended over the nodal Schwann cell microvilli. There were no regional differences in filipin labelling of the nodal-paranodal Schwann cell plasma membrane in relation to features such as paranodal cytoplasmic columns or mesaxonal furrows. However, the paranodes of adjacent Schwann cells were sometimes markedly different from each other in the amount of filipin labelling. The extent to which filipin labelling is indicative of cholesterol membrane content is discussed and the findings are related to current concepts of distribution, mobility and interaction of protein and lipid in biomembranes, with particular reference to the nodal axolemma.

Distribution of filipin-sterol complexes in the myelinated nerve fiber.

Using filipin as a cytochemical probe to reveal the distribution of cholesterol, myelinated peripheral nerve fibers were examined in freeze-fracture replicas. Filipin-sterol complexes were most abundant in the Schwann cell and axonal plasma membranes. In the Schwann cell plasma membrane there was no heterogeneity in complex distribution in relation to the subjacent cytoplasmic network. In myelin lamellae there was a decrease in complexes from outer to inner lamellae and some aggregation of complexes in individual lamellae. The density of complexes in cytoplasmic organelles varied from absent in mitochondria to high in lysosome-like bodies. The results are interpreted in terms of the related biochemical composition and biophysical properties of cell membranes, with particular reference to the myelinated nerve fiber. The influence of diffusion barriers and gradients on the formation of complexes by filipin is considered.

Nodes of Ranvier and Schmidt-Lanterman incisures: an in vivo lanthanum tracer study.

The permeability of the tight junctional system of myelin, at the juxtanodal myelin terminal loops and Schmidt-Lanterman incisures, was investigated using the ionic tracer lanthanum (a) in vivo followed by fixation, (b) concurrently with fixation, (c) following fixation. Employing the same methods the juxtanodal membrane complex formed between myelin loops and axolemma was also tested. The results of this study demonstrate that the periaxonal space (between axon and Schwann cell) is apparently accessible to lanthanum via the myelin loop-axolemmal junction, irrespective of the mode of exposure of myelinated fibres to the tracer. Similarly, the tight junctions between adjacent myelin terminal loops apparently do not prevent lanthanum penetration either in living or in fixed nerves. By contrast the tracer obtained access to the extracellular space within incisures only in vivo. The results are interpreted in terms of the permeability of nodes and incisures in vivo to physiologically important ions and related to current concepts of the electrophysiology of the myelinated nerve fibre.

Myelinated nerve fibres and the fate of lanthanum tracer: an in vivo study.

The permeability of the marginal tight junctional system of myelin was tested in the rat employing the electron-dense tracer lanthanum nitrate. Lanthanum was either included in the fixative used for vascular perfusion (at a concentration of 20 mM) or was microinjected in vivo into the sural or tibial nerve (5, 10 and 20 mM). After 5-60 minutes, the microinjected nerves were fixed either by immersion or vascular perfusion. Lanthanum tracer was present in the intraperiod line gap of myelin, irrespective of the mode of application of the tracer, the method of fixation or the time of exposure to lanthanum. However, the tracer was present more extensively when included in the fixative compared with in vivo microinjection. Internodally, lanthanum was usually restricted to the inner, or more commonly, the outer lamellae of larger fibres, while all lamellae were usually penetrated by tracer in smaller fibres. Paranodally, compact myelin was more extensively penetrated. The periaxonal space (between axon and Schwann cell) was readily accessible to tracer. It is concluded that the marginal tight junctional system of myelin is apparently of the 'leaky' type and is permeable to ions. The findings have implications for the electrophysiology and pathophysiology of the myelinated nerve fibre.

Some scanning electron microscopic features of human cervical epithelium in cell culture.

Human cervical epithelial cells, growing out in confluent monolayers from small explants, develop cytoplasmic extensions from the margins of the growth, extending out and terminating on the glass substrate. The marginal fibrils are particularly frequent on the edges of cellular lamellipodia, protruding in advance of the growing edges. Marginal cells with microvilli tend to have more marginal fibrils on their leading edges than smooth more differentiated cells, and occasionally there is continuity between microvilli and marginal fibrils. Where there is cellular overlap, marginal fibrils extending over the surface of another cell can be seen; where these is an intercellular cleft, cytoplasmic bridges have the same appearance as marginal fibrils. Colchicine (10-6 M) did not affect marginal fibril formation.

Effects of capsaicin applied locally to adult peripheral nerve. II. Anatomy and enzyme and peptide chemistry of peripheral nerve and spinal cord.

(1) Capsaicin solution was applied for 15 min around a 1 cm length of sciatic nerve in the mid upper leg of adult rats. (2) Electron microscopic examinations of the nerve in the treated region after 14 days shows no signs of degeneration of either myelinated or unmyelinated fibres attributable to the capsaicin. (3) Fluoride resistant acid phosphatase FRAP disappears from the central terminals of the treated nerve by 7 days. (4) 1.5 mM capsaicin is sufficient to product a complete reduction of FRAP in the spinal cord. (5) The peptides substance P and cholecystokinin (CCK) are markedly depleted in the region of spinal cord terminations of the treated nerve at 14 days. (6) Substance P and CCk are not affected in spinal cord regions other than in the unmyelinated afferent terminal zone. Similarly neurotensin and neurophysin which are not present in afferent fibres are not influenced by capsaicin treatment of the sciatic. (7) It is concluded that there are chemical changes in the spinal cord terminals of fine afferents after local peripheral capsaicin.

Routine preparation of seminal fluid specimens for transmission electron microscopy.

A technique is described for the routine preparation of seminal fluid specimens for transmission electron microscopy. The method is applicable to cases where examination of sperm morphology is required and can also be used for the indentification of non-spermatozoal cells and their inclusions.

The effect of blood flow on the surface morphology of the human endothelium.

The endothelial lining from the aortae of three 17 week human fetuses was examined by scanning electron microscopy. Orientation of the endothelial cells, particularly in the region above the aortic valve, was related to known flow patterns. Endothelial morphology showed regional variation noticeably at the mouths of arteries and at the aortic bifurcation. The possibility that this morphological change may be a hitherto unrecognised risk factor related to the site of atheromatous deposition is discussed.

Amine oxidase histochemistry of the human uterus during the menstrual cycle.

The enzymes monoamine oxidase A (MAO A), monoamine oxidase B (MAO B) and benzylamine oxidase (BzAO) have been locaized histochemically in the human uterus during various phases of the menstrual cycle. The results show a large increase in MAO A activity in th endometrial gland cells in the secretory phase of the cycle. MAO B activity was found in both endometrium and myometrium but did not show a cyclical variations in activity. BzAO was localized primarily in the tunica media of the myometrial blood vessels. These observations have been supported by parallel biochemical assay.s

A coupled peroxidatic oxidation technique for the histochemical localization of monoamine oxidase A and B and benzylamine oxidase.

A coupled peroxidatic oxidation technique is presented which employs benzylamine and tyramine as substrates and clorgyline, deprenyl, phenelzine and pargyline as specific inhibitors. Using this technique with frozen sections of human term placenta and rat liver, the histochemical localization of monocamine oxidase A and B and bnezylamine oxidase has been demonstrated.

In vivo production of the nucleolar channel system in post menopausal endometrium.

Endometrial biopsies from seven postmenopausal women on hormone replacement therapy have been examined for the presence of the unique nuclear structure, the nucleolar channel system. Its identification in five of the patients has demonstrated that the nucleolar channel system can be produced by an appropriate oestrogen and progestagen treatment and is not otherwise dependent on ovulation.