RESUMEN

It is often assumed that future coastal cliff retreat rates will accelerate as global sea level rises, but few studies have investigated how SLR (sea level rise) might change cliff-front wave dynamics. Using a new simple numerical model, this study simulates the number and type (breaking, broken, or unbroken) of cliff-front waves under future SLR scenarios. Previous research shows breaking waves deliver more energy to cliffs than broken waves, and unbroken waves generate minimal impact. Here, we investigated six cliff-platform profiles from three regions (USA, New Zealand, and UK) with varied tidal ranges and wave climates. Model inputs included 2013-2100 hindcast/forecast incident wave height and tidal water level, and three future SLR scenarios. Results show the number of both cliff-front breaking and broken waves generally increase for a high-elevation (relative to tide) cliff-platform junction. In contrast, breaking/broken wave occurrence decrease by 38-92% for a near-horizontal shore platform with a low-elevation cliff-platform junction under a high SRL scenario, leading to high (96-97%) unbroken wave occurrence. Overall, results suggest the response of cliff-front waves to future SLR is complex and depends on shore platform geometries and SLR scenarios, indicating that future cliff retreat rates may not homogeneously accelerate under SLR.

RESUMEN

Sex allocation theory assumes individual plasticity in maternal strategies, but few studies have investigated within-individual changes across environments. In house wrens, differences between nests in the degree of hatching synchrony of eggs represent a behavioural polyphenism in females, and its expression varies with seasonal changes in the environment. Between-nest differences in hatching asynchrony also create different environments for offspring, and sons are more strongly affected than daughters by sibling competition when hatching occurs asynchronously over several days. Here, we examined variation in hatching asynchrony and sex allocation, and its consequences for offspring fitness. The number and condition of fledglings declined seasonally, and the frequency of asynchronous hatching increased. In broods hatched asynchronously, sons, which are over-represented in the earlier-laid eggs, were in better condition than daughters, which are over-represented in the later-laid eggs. Nonetheless, asynchronous broods were more productive later within seasons. The proportion of sons in asynchronous broods increased seasonally, whereas there was a seasonal increase in the production of daughters by mothers hatching their eggs synchronously, which was characterized by within-female changes in offspring sex and not by sex-biased mortality. As adults, sons from asynchronous broods were in better condition and produced more broods of their own than males from synchronous broods, and both males and females from asynchronous broods had higher lifetime reproductive success than those from synchronous broods. In conclusion, hatching patterns are under maternal control, representing distinct strategies for allocating offspring within broods, and are associated with offspring sex ratios and differences in offspring reproductive success.

Asunto(s)

RESUMEN

In birds, the duration of egg incubation (the time from incubation onset to hatching) can affect multiple components of nest success, but what affects incubation duration? Previous studies suggest that incubation duration is affected by both parental behavior and components of the egg, which have yet to be determined. One egg component that may be related to incubation behavior and the time until hatching is eggshell porosity, which affects the exchange of metabolic gasses and water vapor across the shell and, thus, the speed of embryonic development and incubation duration. We tested whether eggshell porosity was associated with the timing of incubation onset by female House Wrens (Troglodytes aedon Vieillot, 1809), and whether porosity varied within clutches in a manner that might be associated with incubation periods and hatching patterns (i.e., synchronous vs. asynchronous hatching). Eggshell porosity was unrelated to the onset of maternal incubation and did not differ between early and later-laid eggs within clutches, but differed significantly among females and covaried with egg size. We conclude that producing all eggshells of similar porosity within clutches, while adjusting incubation onset once most or all eggs are laid, provide facultative maternal control over variation in hatching patterns.

RESUMEN

In many species, females produce fewer offspring than they are capable of rearing, possibly because increases in current reproductive effort come at the expense of a female's own survival and future reproduction. To test this, we induced female house wrens (Troglodytes aedon) to lay more eggs than they normally would and assessed the potential costs of increasing cumulative investment in the three main components of the avian breeding cycle - egg laying, incubation and nestling provisioning. Females with increased clutch sizes reared more offspring in the first brood than controls, but fledged a lower proportion of nestlings. Moreover, nestlings of experimental females were lighter than those of control females as brood size and prefledging mass were negatively correlated. In second broods of the season, when females were not manipulated, experimental females laid the same number of eggs as controls, but experienced an intraseasonal cost through reduced hatchling survival and a lower number of young fledged. Offspring of control and experimental females were equally likely to recruit to the breeding population, although control females produced more recruits per egg laid. The reproductive success of recruits from broods of experimental and control females did not differ. The manipulation also induced interseasonal costs to future reproduction, as experimental females had lower fecundity than controls when breeding at least 2 years after having their reproductive effort experimentally increased. Finally, females producing the modal clutch size of seven eggs in their first broods had the highest lifetime number of fledglings.

Asunto(s)

RESUMEN

This study aimed to evaluate the diagnostic reliability of sentinel lymph node biopsy in patients with squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, and larynx by reviewing the published literature. A systematic literature review was performed using MEDLINE from 1970 to 2011. With Boolean search strings, search terms included sentinel node, supraglottic, supraglottis, tongue, head and neck, oral, pharynx, laryngeal, and larynx. Additional studies were identified through article references. Duplicate data and articles were excluded based on treating institution and study inclusion time period. Additional studies were excluded if the head and neck subsite or tumor stage was not specifically identified or if the sentinel lymph node biopsy occurred in previously treated necks. All patients had sentinel lymph node biopsy performed followed by a concurrent neck dissection. Twenty-six studies met our inclusion criteria (n = 766 patients). The pooled sensitivity and negative predictive value of SLNB for all head and neck tumors was 95 % (95 % CI 91-99 %) and 96 % (95 %CI 94-99 %), respectively. The overall sensitivity and negative predictive value of SLNB in the subset of oral cavity tumors (n = 631) was 94 % (95 % CI 89-98 %) and 96 % (95 % CI 93-99 %), respectively. One-hundred percent of oropharyngeal (n = 72), hypopharyngeal (n = 5), and laryngeal (n = 58) tumor sentinel lymph biopsy results correlated with subsequent neck dissections giving a negative predictive value of 100 %, showing that, sentinel lymph node biopsy is a valid diagnostic technique to correctly stage regional metastases in patients with head and neck squamous cell carcinoma.

Asunto(s)

RESUMEN

Single components of the immune system are widely used to assess immune function in free-living vertebrates. However, as different immunological components are triggered by different types of threats and may be regulated independently, there is little reason to assume that they should respond similarly if challenged. We investigated whether three commonly assayed immune responses, cutaneous immune activity (phytohaemagglutinin assay), antibody response (tetanus toxoid immunization), and plasma bactericidal activity (Escherichia coli killing) are positively related in nestling house wrens (Troglodytes aedon). Multivariate analysis revealed significant differences in overall immune responsiveness among broods (i.e. nests), primarily attributable to differences in plasma bactericidal activity. Among broods, humoral immune response was negatively related to cutaneous immune activity and positively related to plasma bactericidal activity. We found no significant relationships among these measures of immunity among individual nestlings within broods. Our results suggest that different broods (i.e. families) invest differentially in the various branches of the immune system. Further study is needed to characterize the roles of maternal, genetic and environmental effects on the expression of this physiological bias.

Asunto(s)

RESUMEN

AIM: To describe the uptake of breast feeding in mothers with either Type 2 diabetes or gestational diabetes (GDM) in a hospital serving a multiethnic community in South Auckland, New Zealand. RESEARCH DESIGN AND METHODS: A retrospective study of all women attending the Diabetes in Pregnancy clinic over a 4-year period was undertaken: 30 women had Type 2 diabetes and 373 GDM. RESULTS: Compared with mothers with GDM, mothers with Type 2 diabetes were less likely to breast feed in any way as the first feed (41.4% vs. 68.0%, P = 0.011) or at discharge (69.0% vs. 84.0%, P = 0.039). In the combined group, there were no differences in uptake of breast feeding by ethnicity, age, parity, body mass index, smoking or antenatal glycaemia, use of insulin or presence of hypertension. Breast feeding on discharge was associated with a higher APGAR score, breast feeding as the first feed (78.2% vs. 19.4%, P < 0.001) and lower rates of delivery by Caesarean section (17.0% vs. 31.8%, P = 0.006). Logistic regression showed breast feeding as the first feed, the major determinant for breast feeding on discharge. CONCLUSIONS: Factors delaying breast feeding as the first feed are the major determinant of breast feeding on discharge. Strategies to increase breast feeding as the first feed among women with Type 2 diabetes, and those having a Caesarean section, may be useful in increasing the uptake of breast feeding in the longer term.

Asunto(s)

RESUMEN

AIMS: To compare the detection of undiagnosed diabetes and dysglycaemia (impaired glucose tolerance, impaired fasting glucose, diabetes) using risk factors and laboratory measures of glycaemia. METHODS: Casual blood glucose samples were taken from 1899 (69.4% of 2737 invited) European, Maori and Pacific Islands subjects aged 40-79 years from randomly selected households in South Auckland, New Zealand. Of these, 534 attended for a 75-g oral glucose tolerance test (OGTT) if an elevated result was identified [327/478 (68.4%)] or if randomly selected with a 'normal' screening result [207/308 (67.2%)]. RESULTS: Several Europeans with undiagnosed diabetes (25.0%) and dysglycaemia (31.4%) had no diabetes risk factors. Most Maori and Pacific Islanders had at least one risk factor. The area under the receiver operating curve (ROC) for the detection of undiagnosed diabetes was 0.92 (0.89-0.95) using fasting glucose, 0.86 (0.82-0.90) using HbA1c, 0.75 (0.69-0.80) using random glucose, but 0.60 (0.55-0.66) using risk factor screening. The ROC for detecting any dysglycaemia was 0.88 (0.85-0.90), 0.68 (0.64-0.71), 0.72 (0.69-0.75), 0.61 (0.58-0.65), respectively. Screening using fasting glucose (the best test) detected 90.4% of new diabetes and 78.4% of dysglycaemia; risk factor screening followed by fasting glucose detected significantly less cases [88 (82-93)% and 86 (82-89)%, respectively] with 9.2% less OGTTs. CONCLUSIONS: Using risk factors for the identification of who should receive a blood test for dysglycaemia adds little to direct screening with the risk of missing some with significant hyperglycaemia. Screening for dysglycaemia may best be undertaken using blood tests without initial risk factor symptom screening.

Asunto(s)

RESUMEN

OBJECTIVE: To describe the use of insulin pump therapy in women with gestational diabetes mellitus (GDM) or type 2 diabetes in pregnancy and persistent hyperglycemia despite multiple injections of subcutaneous insulin. RESEARCH DESIGN AND METHODS: As part of a service audit, deliveries to women with diabetes at a single South Auckland hospital were reviewed from 1991 through 1994. Glycemic control was estimated by the mean of self-recorded and laboratory postprandial glucose concentrations. In a nested case-control study, pregnancies complicated by GDM/type 2 diabetes with use of an insulin pump were compared with those without insulin pump therapy and peak insulin requirements of 100-199 units/ day, matched for ethnicity and type of diabetes. RESULTS: A total of 30 of 251 Polynesian, European, and South Asian women with singleton pregnancies complicated by insulin-requiring GDM/type 2 diabetes used an insulin pump. An additional two women with high insulin requirements discontinued pump therapy. None of the women with GDM/type 2 diabetes experienced severe hypoglycemia, whereas 79% of the women had improved glycemic control within 1-4 weeks. Mothers using a pump had greater insulin requirements (median maximum 246 vs. 130 units per day) and greater weight gain (10.6 vs. 5.0 kg). Their babies were more likely to be admitted to the Special Care Baby Unit but were neither significantly heavier nor experienced greater hypoglycemia than control subjects. CONCLUSIONS: Insulin pump therapy seems to be safe and effective for maintaining glycemic control in pregnancies complicated by GDM/type 2 diabetes and requiring large doses of insulin.

Asunto(s)

RESUMEN

The natural product FR901464 (1) was isolated by the Fujisawa Pharmaceutical Co. and shown to have intriguing biological properties including impressive antitumor activity. In this paper we describe the first total synthesis of 1 in full detail. A chiral building block synthetic strategy was used to assemble the target: optically active components were generated using asymmetric catalytic reactions, and these fragments were coupled together at a late stage in a convergent synthesis. In particular, a versatile, asymmetric hetero-Diels-Alder (HDA) reaction was developed in the context of this synthesis and used with great effectiveness for the preparation of the two densely functionalized pyran rings. The flexible nature of the synthetic route also allowed us to prepare a series of analogues of 1. These compounds were used to prove the relative stereochemistry of the natural product as well as to probe the importance of certain structural features of FR901464 with regard to biological activity.

Asunto(s)

RESUMEN

AIMS: To compare the extent of hyperinsulinaemia among New Zealand Europeans and Polynesians (an ethnic group at high risk of Type 2 diabetes mellitus). METHODS: A cross-sectional survey from randomly selected households was conducted in inner urban South Auckland. Subjects were either European, Maori or Pacific Islands Polynesians aged 40-79 years and were screened for diabetes using a random blood glucose. Those with an elevated result, and 20% randomly selected from those with a normal screening result, were invited to a 75-g glucose tolerance test. WHO criteria (1998) for diabetes were used. RESULTS: In those aged 40-59 years, total prevalence of diabetes was 7.5 (6.2-9.0)% in Europeans but 21.1 (16.6-25.6)% among Maori and 25.0 (19.8-30.1)% among Pacific peoples; obesity (body mass index >or= 31.0 kg/m2) was present in 26% Europeans, 63% Maori and 69% Pacific peoples. Non-diabetic Polynesians were relatively hyperglycaemic and hyperinsulinaemic. After adjusting for the degree of obesity, Polynesians had similar insulin levels to Europeans. CONCLUSIONS: These findings indicate that Polynesians are not intrinsically insulin resistant as a group, a prerequisite found in most other ethnic groups at high risk of Type 2 diabetes mellitus. The high prevalence of Type 2 diabetes in Polynesians could be the result of their high prevalence of obesity.

Asunto(s)

RESUMEN

AIMS: Familial clustering of diabetes and nephropathy suggests that either common environmental or inherited mechanisms are important in developing diabetic nephropathy. If an inherited mechanism is important, the albumin excretion rate might be increased in those at future risk. This study aimed to determine whether people with a family history of diabetes or people with a family history of renal disease were most at risk. METHODS: In a two-by-two factorial study of urinary albumin in non-diabetic Polynesians, 90 people with a first degree relative (FDR) with end-stage renal failure (ESRF) and diabetes (group 1) were compared with 90 people with a FDR with non-diabetic ESRF (group 2), with 90 people with a FDR with diabetes but no known nephropathy (group 3) and 90 people with no known relatives with either diabetes or nephropathy (group 4). Groups were matched for ethnicity and age. RESULTS: Subjects with a family history of ESRF (groups 1 and 2) had an increased mean albumin-creatinine ratio (1.25 vs. 1.00 mg/mmol, P = 0.01), but in subjects with a family history of diabetes (groups 1 and 3), the mean ratios were not significantly different from those without a family history of diabetes (1.06 vs. 1.17 mg/mmol; P = 0.2). In those with a family history of nephropathy, fasting blood glucose and systolic blood pressure were increased, while fasting insulin and 2 h insulin concentrations were lower. A family history of diabetes was associated with an increased fasting blood glucose and 2-h blood glucose. By multiple linear regression, the mean systolic blood pressure (P = 0.02), the 2-h glucose concentration (P = 0.05), a family history of renal failure (P = 0.04), female sex (P = 0.0001) and the total cholesterol (P = 0.01) were each independently associated with microalbuminuria, while a family history of diabetes was not (P = 0.09). CONCLUSIONS: These data suggest that among Polynesians there is no specific inherited tendency to diabetic nephropathy per se. The risk of nephropathy does not appear to be associated with the degree of familial risk of diabetes itself. Rather, the risk of diabetic nephropathy may be the result of a familial risk of nephropathy from any cause and is associated with diabetes through relative hypoinsulinaemia and hyperglycaemia.

Asunto(s)

RESUMEN

AIMS: To describe the incidence and risk factors for neonatal hypoglycaemia among the offspring of women with gestational diabetes mellitus (GDM) in South Auckland, New Zealand METHODS: A retrospective audit was undertaken of singleton pregnancies delivered between 1991 and 1994. Data were obtained for 373 women and their deliveries (57 European, 76 Maori, 198 Pacific Islands, 42 other). RESULTS: Pacific Islands women were most likely to have large babies with neonatal hypoglycaemia in spite of a high use of insulin. Postnatally Maori and Pacific Islands women had a high incidence of Type 2 diabetes mellitus (21.4, 21.7 vs. 4.3% Europeans, 12.0% others, P =0.035). Babies experiencing hypoglycaemia were more likely to have a mother with past GDM (51.2 vs. 27.2%, P = 0.01) and greater hyperglycaemia (at diagnosis fasting 6.8 +/- 1.7 vs. 5.7 +/- 1.1 mmol/l, P < 0.001; finger-prick glucose 5.7 +/- 1.0 vs. 5.2 +/- 0.8 mmol/l, P < 0.001). Macrosomia, Caesarian section and special care baby unit admission were more common in pregnancies complicated by neonatal hypoglycaemia. CONCLUSIONS: Maternal hyperglycaemia was a major contributing factor to neonatal hypoglycaemia in this population. Undiagnosed Type 2 diabetes was common among Maori and Pacific Islands women, confirming the need for earlier detection and treatment.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Organochlorine pesticide levels were determined in Neotropical migrant passerines which have populations reported to be declining. Pesticide residues ranging from 0.385 to 27.4 ng/g were found in 19 of 21 birds, including both Hatch Year (HY) and After Hatch Year (AHY) age classes of nine different species. Eighteen of the 19 birds contained p,p'-DDE, while dieldrin was found in 16 birds and heptachlor epoxide was present in 10 birds. There were no significant differences in pesticide levels between HY and AHY birds, suggesting that HY birds are exposed to pesticides in their diet on the breeding ground or that pesticides are acquired from contaminated mothers, or both. Pesticide levels were not related to gender. Although the effects of these low residue levels on passerine fecundity are unknown, their presence has potential conservation implications for passerines and for the raptorial birds that feed upon them.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)