Syndromic obesity and diabetes: changes in body composition with age and mutation analysis of ALMS1 in 12 United Kingdom kindreds with Alstrom syndrome

CONTEXT

Alström syndrome (AS) is a monogenic form of infancy-onset obesity and insulin resistance, caused by ALMS1 mutations. The natural history of the insulin resistance is unknown, in particular how this relates to changes in body composition. It is also unclear how ALMS1 mutations relate to the characteristic phenotype.

OBJECTIVES

Our objectives were to characterize body composition and metabolic parameters, to establish ALMS1 mutation spectrum of United Kingdom AS patients, and to determine whether a genotype-phenotype correlation exists.

DESIGN AND PATIENTS

We conducted a cross-sectional cohort study of 12 unrelated subjects with AS. Age-standardized body composition was assessed by anthropometry and dual-energy x-ray absorptiometry and insulin sensitivity by homeostasis model assessment. The exons and intron-exon boundaries of ALMS1 were directly sequenced.

SETTING

The study was performed during the annual Alström Syndrome UK multidisciplinary screening clinic.

RESULTS

AS patients have early-onset obesity, but body mass index, waist circumference, and body fat from dual-energy x-ray absorptiometry were negatively correlated with age (r = -0.37, P = 0.2; r = -0.84, P = 0.002; and r = -0.6, P = 0.05). Despite this, insulin resistance increased, demonstrated by raised fasting insulin and fall in homeostasis model assessment insulin sensitivity with age (r = -0.64, P = 0.02). ALMS1 mutations were identified in 10 of 12 patients, with a potential founder mutation in exon 16 present in five [np 10775del (C); Del3592fs/ter3597]. No genotype-phenotype correlation was observed.

CONCLUSIONS

We identified mutations in ALMS1 in more than 80% of patients with no genotype-phenotype correlation. In AS, severe childhood obesity, waist circumference, and body fat decrease with age, whereas insulin resistance increases. The abdominal obesity, insulin resistance, diabetes, hypertriglyceridemia, and hypertension suggest that AS could represent a monogenic model for the metabolic syndrome.

Inactivation of frog virus 3 and channel catfish virus by esculentin-2P and ranatuerin-2P, two antimicrobial peptides isolated from frog skin

While it is clear that some amphibian populations have recently experienced precipitous declines, the causes of those die-offs are complex and likely involve multiple variables. One theory suggests that environmental factors may trigger events that result in depressed immune function and increased susceptibility to infectious disease. Here we examine one aspect of innate immunity in amphibians and show that esculentin-2P (E2P) and ranatuerin-2P (R2P), two antimicrobial peptides isolated from Rana pipiens, inactivate frog virus 3, a potentially pathogenic iridovirus infecting anurans, and channel catfish herpesvirus. In contrast to mammalian antimicrobial peptides, E2P and R2P act within minutes, at temperatures as low as 0 degrees C, to inhibit viral infectivity. Moreover, these compounds appear to inactivate the virus directly and do not act by inhibiting replication in infected cells. This is the first report linking amphibian antimicrobial peptides with protection from an amphibian viral pathogen and suggests that these compounds may play a role in maintaining amphibian health.

Infectious disease and worldwide declines of amphibian populations, with comments on emerging diseases in coral reef organisms and in humans

Many populations of amphibians are declining on all six continents on which they occur. Some causes of amphibian declines, such as habitat destruction, direct application of xenobiotics, and introduction of predators or competitors, are clearly attributable to human activities. Infectious disease appears to be the direct cause of mass amphibian die-offs in relatively undisturbed areas of the world where anthropomorphic environmental disruption is minimal. In these cases, it is not yet clear whether these epizootics result from the natural evolution of new pathogens or from environmental changes that promote the emergence of pathogenic forms and/or that weaken the immune defenses of amphibians. Because some aspects of pathogen-related amphibian mass mortalities are similar to outbreaks of new diseases in humans and coral reef organisms, amphibian declines may be part of a much larger pattern than previously appreciated.

Effect of high altitude and in vivo adenosine/(β)-adrenergic receptor blockade on ATP and 2,3BPG concentrations in red blood cells of avian embryos

In chick embryos, developmental changes of the blood oxygen tension control hemoglobin (Hb) oxygen affinity via modulation of ATP and 2, 3BPG concentrations in red blood cells. Hypoxia, which is a normal developmental condition for late chick embryos, causes a decrease of the red cell ATP concentration (and increase of red cell oxygen affinity) as well as activation of 2,3BPG synthesis via cyclic AMP-dependent signaling. Adenosine and catecholamines have been implicated as signaling substances in these red cell responses. To assess the extent to which adenosine and catecholamines are involved in vivo in the control of red cell ATP/2,3BPG concentrations, day 13 chick embryos were treated for 24 h with adenosine A(2) and/or (β)-adrenergic receptor blockers and red cell ATP and 2,3BPG levels were determined. The data suggest that adaptive effects later in development in chick embryos induced by adenosine and catecholamines are vital. We have also tested whether avian embryos of the free-living, high-altitude, native white-tailed ptarmigan (Lagopus leucurus) alter their organic phosphate pattern in red cells in response to incubation at different altitudes. Embryos incubated at 3600–4100 m decrease their red cell ATP concentration much more rapidly than embryos of the same clutch incubated at 1600 m. From these data it can be inferred that the oxygen affinity of high altitude embryos will be adjusted to the altitude at which the eggs are incubated.

Uncemented total hip arthroplasty in Paget's disease of the hip: a report of 5 cases with 5-year follow-up

Five patients with Paget's disease localized to the acetabulum received cementless acetabular components during total hip replacement. Three were primary surgeries, and 2 were revisions of a failed cemented acetabular component. At an average of 5.8 years (range, 4.8-8.8 years) after the operation, all acetabular components were well fixed radiographically with no migration or loosening. No patients complained of clinical symptoms referable to the acetabular component. No revisions had been performed. The ability of this inherently abnormal bone to proceed through the reparative and remodeling phases of porous ingrowth adds support to the use of uncemented components for acetabular reconstruction in Paget's disease of the hip.

Amphibian declines: an immunological perspective

Many, but not all, amphibian populations have been declining on all six continents on which they live. Although habitat destruction, direct application of toxicants, and introduction of predators/competitors are obvious causes of amphibian declines, many amphibians are dying of infectious diseases in relatively pristine habitats on several continents. In this paper, we review the patterns of these disease outbreaks and the characteristics of amphibian immune systems. Hypotheses are presented to explain the apparent susceptibility of amphibians to these pathogens. Natural and man-made factors that can alter amphibian immune responses to pathogens are discussed. Additional research is needed on the biology of the specific pathogens, the pattern of immune responses they elicit, and the nature of environmental stressors that may increase susceptibility to infectious disease.

Reversible depression of oxygen consumption in isolated liver mitochondria during hibernation

The biochemical mechanisms by which hibernators cool as they enter torpor are not fully understood. In order to examine whether rates of substrate oxidation vary as a function of hibernation, liver mitochondria were isolated from telemetered ground squirrels (Spermophilus lateralis) in five phases of their annual hibernation cycle: summer active, and torpid, interbout aroused, entrance, and arousing hibernators. Rates of state 3 and state 4 respiration were measured in vitro at 25 degrees C. Relative to mitochondria from summer-active animals, rates of state 3 respiration were significantly depressed in mitochondria from torpid animals yet fully restored during interbout arousals. These findings indicate that a depression of ADP-dependent respiration in liver mitochondria occurs during torpor and is reversed during the interbout arousals to euthermia. Because this inhibition was determined to be temporally independent of entrance and arousal, it is unlikely that active suppression of state 3 respiration causes entrance into torpor by facilitating metabolic depression. In contrast to the observed depression of state 3 respiration in torpid animals, state 4 respiration did not differ significantly among any of the five groups, suggesting that alterations in proton leak are not contributing appreciably to downregulation of respiration in hibernation.

Conversion of hemiarthroplasty to total hip arthroplasty: can groin pain be eliminated?

In this study 45 patients with groin or buttock pain after hemiarthroplasty were evaluated 2 to 7 years after conversion to total hip arthroplasty. Groin or buttock pain was completely relieved in 36 patients (80%) and partially relieved in an additional 4 patients (9%). After conversion surgery, 9 patients continued to have groin or buttock pain, but no factor could be identified that would predict an unsuccessful result. The hypothesis tested in this study was whether conversion of a hemiarthroplasty to a total hip arthroplasty eliminates groin pain. Because a significant number of patients (up to 20%) will continue to have some groin or buttock pain after conversion surgery, patients should be warned of this contingency before surgery.

Correlation of the heart rate-minute ventilation relationship with clinical data: relevance to rate-adaptive pacing

The heart rate (HR)-minute ventilation (VE) relationship has been shown to be nonlinear and can be expressed as two distinct straight lines. This study is to assess the correlation of the initial HR-VE slope to clinical parameters. Maximum treadmill exercise tests were performed in 100 healthy volunteers (age 19-77 years) using a ramp protocol in which work-rate increases linearly with exercise. Breath-by-breath VO2, VCO2, and VE were measured, and HR and BP were monitored throughout the exercise. The HR-VE curve demonstrated nonlinearity with a breakpoint determined by a change point analysis. This breakpoint was significantly higher than that of the anaerobic threshold. The VE at the HR-VE breakpoint was 56.4 +/- 19.4 and VE at the VE-VO2-VO2 breakpoints were 48.0 +/- 18.3 (P < 0.0001) and 40.1 +/- 16.5 (P < 0.0001), respectively. The HR at this HR-Ve breakpoint was 77.7 +/- 12.9% of the HR range. The first slope, S1 (1.76 +/- 0.64) was steeper than the second slope, S2 (0.66 +/- 0.39). Although there was a gender difference for S1, the best clinical predictor on a stepwise multiple regression analysis was body surface area (BSA) which explained 47% of the variance. It was concluded that nonlinearity of the HR-VE curve can be expressed as two straight lines. The breakpoint is beyond the anaerobic threshold and can be estimated to be approximately 75% of the maximal predicted HR. BSA is the only clinical parameter that significantly predicts the initial slope of the HR-VE curve. This can be of great importance in the programming of rate-adaptive pacemakers using a VE.

Patient education in arthritis: randomized controlled trial of a mail-delivered program

OBJECTIVE

Self-management courses in arthritis have been shown to improve outcomes and to decrease medical resource utilization. We studied the effectiveness of a mail-delivered arthritis self-management program with the potential for extending these effects more broadly.

METHODS

Randomized controlled trial of 375 program participants and 434 controls over a 6 month period. Baseline and 6 month data were analyzed for each group and between groups by paired 2 sample t test. The intervention consists of health assessment questionnaires at 3 month intervals, with computer processed recommendation letters and reports individualized to age, diagnosis, education level, disability, pain, medication, and other patient-specific variables.

RESULTS

At 6 months, outcomes of function (4.7%; 95% confidence limits 2.7, 6.7), decreased pain (9%; 2.8, 15.2), global vitality (7%; 2.8, 11.2), and joint count (28%; 20, 36) were improved in the program group compared with controls (p < 0.01). Exercise (35%; 26, 44) and self-efficacy (14.7%; 9, 20) were increased in the program group but not controls (p < 0.001). Doctor visits/year were decreased by 16% (3, 29) in the program group compared with controls (p < 0.05) and days missed work or confined to home decreased by 52% (-3, 107) in the program group compared with controls (p = 0.06). At one year, patients in the original program group continued to improve, and the control group, provided with the program in the second 6 months, showed improvement similar to the first 6 months of the original program group.

CONCLUSION

A mail-delivered arthritis self-management program can positively affect patient outcomes and can decrease medical resource utilization.

Beyond CHELP: improved potential derived charges for sugars

The partitioning of the overall molecular charge distribution into atom centered monopole charges, while quantum mechanically ill-defined, is nevertheless a technique which finds applications in several broad classes of chemical problems. Charges derived from fits to electrostatic potentials have an intuitive appeal since, in principle, these could be derived from either theoretical or experimental data. It has been noted, however, that such potential derived charges can be conformationally dependent in ways that do not appear to reflect the changes in the molecular wavefunction. Both the algorithm used for selecting points at which the molecular electrostatic potential will be fit and the density of points used in the fit have been suggested to influence the resultant charges. Recently [Stouch TR, Williams DE (1992) J Comp Chem 13: 622-32; Stouch TR, Williams DE (1993) J Comp Chem 14: 858-66] it has been noted that numerical difficulties may make it impossible to fit all the atomic charges in a molecule. Singular value decomposition (SVD) of the linear least squares matrices used in fitting atom based monopoles to molecular electrostatic potentials provides a tool for evaluating the integrity of the calculated charges. Based on the SVD analysis for a selected group of molecules we have noted particularly that increasing the molecular size reduces the fraction of charges which can be validly assigned. Users of PD derived charges, especially those who are using those charges for tasks other than reproduction of the MEP, should be aware that there is a high probability that a significant portion of those charges are statistically unreliable. Therefore, charges in many biological molecules, such as sugars, prove to be difficult to obtain by potential derived (PD) methods such as CHELP or CHELPG. Results from the SVD can be used to both assess PD charges and to generate an improved, albeit incomplete, set. Improved PD fits are presented for a series of simple saccharides.

Oxygen Transport System of High-Altitude Bird Embryos

In the absence of its mother's protection, a bird embryo incubated at high altitude must detect its hypoxic condition and regulate its oxygen transport so as to hatch and grow with the same efficiency as it would at sea level.

Changes in selected aspects of immune function in the leopard frog, Rana pipiens, associated with exposure to cold

The effect of exposure to low temperatures (5 degrees C) on lymphocyte proliferation, leukocyte populations, and serum complement levels was examined in the northern leopard frog, Rana pipiens. Proliferation of T lymphocytes in response to phytohemagglutinin stimulation was significantly decreased in frogs kept for 2, 3, and 5 months at 5 degrees C compared to that of animals kept at 22 degrees C. A significant increase in the average percentage of neutrophils and a decrease in the mean percentage of eosinophils was observed in the blood of frogs held for 5 months in the cold compared to animals held at 22 degrees C for the same length of time. Mean serum complement activity after 1 month at 5 degrees C was significantly reduced in comparison to animals held at 22 degrees C and was not detectable after 5 months in the cold. Recovery of complement levels at room temperature (22 degrees C) was also examined after cold exposure. Complement levels were significantly higher than controls (at 22 degrees C) in frogs returned to 22 degrees C for 7 and 14 days after 5 months in the cold. After frogs were held at 5 degrees C for 1 month, serum complement levels increased significantly within 2 days after returning to 22 degrees C and continued to rise 5 and 9 days after warming. Injections with Aeromonas hydrophila following a 5-week exposure to 5 degrees C failed to cause death or observable symptoms of disease in frogs that were returned to 22 degrees C.

Relationship between polyethylene wear, pelvic osteolysis, and clinical symptomatology in patients with cementless acetabular components. A framework for decision making

The purpose of this study is to assess the relationship between acetabular component polyethylene wear, pelvic osteolysis, and clinical symptoms to determine when operative intervention should occur and to predict the degree of difficulty of the revision. Fifty-four revisions of failed cementless acetabular components were performed in 52 patients. All cases demonstrated polyethylene wear radiographically, and in 43 cases (80%), osteolysis of the pelvis was seen. Symptoms of groin or buttock pain were seen in 45 of 54 cases (83%). Preoperative staging of the disease process included one patient with wear radiographically but neither symptoms nor lysis (stage I), 10 patients with wear and pain (stage IIA), 8 patients with wear and lysis but no pain (stage IIB), and 35 patients with wear, lysis, and pain (stage III). Patients in stages I and IIA could be revised with cementless components without structural allograft. Patients in stages IIB and III required structural allograft in 79% and cemented components in 53%. Cemented components were used when there was less than 50% contact between host-bone and prosthesis. Polyethylene wear alone (stage I) is an indication of impending failure, and when symptoms develop (stage IIA), revision should be undertaken. The development of radiographic lysis is a critical event, and as soon as osteolysis develops (stage IIB or III), revision should be undertaken immediately. From the perspective of the revision surgeon, there is great value in the early intervention for polyethylene wear and pelvic osteolysis.

Targeted ablation of pituitary pre-proopiomelanocortin cells by herpes simplex virus-1 thymidine kinase differentially regulates mRNAs encoding the adrenocorticotropin receptor and aldosterone synthase in the mouse adrenal gland

We have produced and characterized lines of transgenic mice expressing a fusion gene composed of the pituitary expression-specific promoter region of the POMC gene, driving the herpes simplex viral-1 thymidine kinase. Adult mice were treated with the antiherpes agent ganciclovir at 70 mg/kg body weight (ip, twice daily for 10-12 days). Approximately 98% of the pituitary intermediate lobe melanotropes and anterior lobe corticotropes were ablated as determined by immunocytochemistry and RIA specific for the POMC-derived peptides, ACTH, beta-endorophin, and alpha-MSH. The number of lactotropes, somatotropes, thyrotropes, and gonadotropes was not altered compared with controls, indicating that in the adult pituitary, POMC products are not required to maintain the distribution of cell types. As expected, plasma corticosterone levels were substantially decreased after POMC cell ablation. In situ hybridization studies showed that the mouse ACTH receptor was expressed uniformly throughout the adrenal cortex, and RNase protection assays revealed that the ACTH receptor mRNA decreased after pituitary POMC cell ablation. Additionally, RNase protection assays showed that pituitary POMC cell ablation resulted in the decrease of adrenal p450c11 beta transcripts while p450c11AS (aldosterone synthase) mRNA levels remained constant. These data demonstrate differential regulation of steroid pathway-specific enzymes by POMC products. Our results also suggest that the thymidine kinase cell obliteration technique may not be dependent on cell division as a prerequisite for cytotoxicity, thus supporting the idea that targeted molecular ablation using cell- and tissue-specific promoter sequences to drive viral thymidine kinase expression can be refined further to study other nonmitotic cells.

Possible interrelations among environmental toxicants, amphibian development, and decline of amphibian populations

Many amphibian populations are declining in a number of geographical locations throughout the world. In most cases, the cause or causes are unknown, but are assumed to result from man-made alterations in the environment. We review existing evidence concerning how environmental xenobiotics could contribute to declines of amphibian populations by impacting growth and development of the young. This paper examines the potential roles of toxicants in: a) affecting the susceptibility of young to disease; b) retarding growth and development of amphibian young; c) affecting the ability of larvae to avoid predation; d) affecting the development of physiological, morphological, or behavioral processes in a manner that subsequently impairs the ability of the young for future reproduction; and e) directly causing mortality of young. These issues are not well studied, and more studies are needed before the roles of environmental xenobiotics in amphibian declines are fully understood.

Blood gases, pH and hematology of montane and lowland coot embryos

Blood gases, air cell-blood gas differences, blood pH, and hematology were compared in embryonic coots (Fulica americana peruviana) at 4150 m and sea level in Peru. Neither arterialized nor venous O2 tensions differed significantly between montane and lowland groups but blood CO2 tensions of the two groups differed significantly. The air cell PO2-arterialized blood PO2 difference of montane eggs was less than half the value in lowland eggs. Both arterialized and venous CO2 tensions differed substantially between montane and lowland groups. Despite these differences, plasma pH at both altitudes was statistically indistinguishable, due in part to variation in plasma [HCO3-]. Hematocrits of montane embryos were significantly higher than that of their lowland counterparts.

The basis of the histamine assay in human skin: II. Wheal formation

1. Subepidermal injection of histamine solutions in isotonic saline in four subjects evoked whealing after a mean delay of 2.6 min, this estimate being derived by regression modelling. 2. Wheal growth was better modelled by the logarithm of time than by time, suggesting that wheal size depends upon assisted diffusion of histamine in the dermis. 3. Wheal growth was piecemeal, not continuous, consistent with the successive involvement of neighbouring vascular territories. 4. Wheal growth was completed by 9 min after injection.

Antishock and endothelial protective actions of a NO donor in mesenteric ischemia and reperfusion

Splanchnic artery occlusion (SAO) of the celiac, superior mesenteric, and inferior mesenteric arteries for 2 hr, followed by a 2-hr reperfusion period in cats produces a severe form of circulatory shock characterized by endothelial dysfunction, increased lysosomal leakage, and severe hypotension resulting from release of proteases, oxygen-derived free radicals, and other humoral mediators into the circulation. Administration of 0.75 mg/kg/hr of C873754, a nitric oxide (NO) donor, 10 min prior to reperfusion, significantly attenuated the accumulation of plasma cathepsin D from 12 +/- 3 U/ml in the SAO + vehicle group to 5 +/- 1 U/ml (P < 0.05) in the C87-3754 treated SAO group. A similar attenuation of plasma myocardial depressant factor (MDF) activity was observed in the C87-3754 treated cats (P < 0.02). Administration of C87-3754 significantly increased short term (i.e., 2-hr) survival rate (P < 0.05, compared to the vehicle group). Moreover, C87-3754 attenuated the SAO shock induced decline in release of endothelium-derived relaxing factor (EDRF) from isolated superior mesenteric artery (SMA) rings stimulated by acetylcholine and A23187. Additionally, C87-3754 significantly decreased PMN adherence to the superior mesenteric venous endothelium in vitro. Thus, treatment with the NO donor, C87-3754 reduced the accumulation of humoral mediators into the plasma while significantly attenuating endothelial dysfunction and improving short term survival.