Effects of vitamin D2 or D3 supplementation on glycaemic control and cardiometabolic risk among people at risk of type 2 diabetes: results of a randomized double-blind placebo-controlled trial.

AIMS: To investigate the effect of short-term vitamin D supplementation on cardiometabolic outcomes among individuals with an elevated risk of diabetes. METHODS: In a double-blind placebo-controlled randomized trial, 340 adults who had an elevated risk of type 2 diabetes (non-diabetic hyperglycaemia or positive diabetes risk score) were randomized to either placebo, 100,000 IU vitamin D2 (ergocalciferol) or 100,000 IU vitamin D3 (cholecalciferol), orally administered monthly for 4 months. The primary outcome was change in glycated haemoglobin (HbA1c) between baseline and 4 months, adjusted for baseline. Secondary outcomes included: blood pressure; lipid levels; apolipoprotein levels; C-reactive protein levels; pulse wave velocity (PWV); anthropometric measures; and safety of the supplementation. RESULTS: The mean [standard deviation (s.d.)] 25-hydroxyvitamin D [25(OH)D]2 concentration increased from 5.2 (4.1) to 53.9 (18.5) nmol/l in the D2 group, and the mean (s.d.) 25(OH)D3 concentration increased from 45.8 (22.6) to 83.8 (22.7) nmol/l in the D3 group. There was no effect of vitamin D supplementation on HbA1c: D2 versus placebo: -0.05% [95% confidence interval (CI) -0.11, 0.02] or -0.51 mmol/mol (95% CI -1.16, 0.14; p = 0.13); D3 versus placebo: 0.02% (95% CI -0.04, 0.08) or 0.19 mmol/mol (95% CI -0.46, 0.83; p = 0.57). There were no clinically meaningful effects on secondary outcomes, except PWV [D2 versus placebo: -0.68 m/s (95% CI -1.31, -0.05); D3 versus placebo -0.73 m/s (95% CI -1.42, -0.03)]. No important safety issues were identified. CONCLUSIONS: Short-term supplementation with vitamin D2 or D3 had no effect on HbA1c. The modest reduction in PWV with both D2 and D3 relative to placebo suggests that vitamin D supplementation has a beneficial effect on arterial stiffness.

Characterisation of Elastic and Acoustic Properties of an Agar-Based Tissue Mimicking Material.

As a first step towards an acoustic localisation device for coronary stenosis to provide a non-invasive means of diagnosing arterial disease, measurements are reported for an agar-based tissue mimicking material (TMM) of the shear wave propagation velocity, attenuation and viscoelastic constants, together with one dimensional quasi-static elastic moduli and Poisson's ratio. Phase velocity and attenuation coefficients, determined by generating and detecting shear waves piezo-electrically in the range 300 Hz-2 kHz, were 3.2-7.5 ms(-1) and 320 dBm(-1). Quasi-static Young's modulus, shear modulus and Poisson's ratio, obtained by compressive or shear loading of cylindrical specimens were 150-160 kPa; 54-56 kPa and 0.37-0.44. The dynamic Young's and shear moduli, derived from fitting viscoelastic internal variables by an iterative statistical inverse solver to freely oscillating specimens were 230 and 33 kPa and the corresponding relaxation times, 0.046 and 0.036 s. The results were self-consistent, repeatable and provide baseline data required for the computational modelling of wave propagation in a phantom.

Carotid atherosclerotic plaque characterisation by measurement of ultrasound sound speed in vitro at high frequency, 20 MHz.

This study aimed to utilise a tissue mimicking material (TMM) in order to embed in vitro carotid plaque tissue so that its acoustic properties could be assessed. Here, an International Electrotechnical Commission (IEC) agar-based TMM was adapted to a clear gel by removal of the particulates. This clear TMM was measured with sound speed at 1540 ms(-1) and an attenuation coefficient of 0.15 dB cm(-1)MHz(-1). Composite sound speed was then measured through the embedded material using a scanning acoustic microscope (SAM). Both broadband reflection and transmission techniques were performed on each plaque specimen in order to ensure the consistency of the measurement of sound speed, both at 21 °C and 37 °C. The plaque was measured at two temperatures to investigate any effect on the lipid content of the plaque. The contour maps from its associated attenuation plots were used to match the speed data to the photographic mask of the plaque outline. This physical matching was then used to derive the sound speed from the percentage composition seen in the histological data by solution of simultaneous equations. Individual speed values for five plaque components were derived; TMM, elastin, fibrous/collagen, calcification and lipid. The results for derived sound speed in the TMM were consistently close to the expected value of soft tissue, 1540 ms(-1). The fibrous tissue showed a mean value of 1584 ms(-1) at 37 °C. The derived sound speeds for elastic and lipid exhibited large inter-quartile ranges. The calcification had higher sound speed than the other plaque components at 1760-2000 ms(-1). The limitations here lay in the difficulties in the matching process caused by the inhomogeneity of the plaque material and shrinkage during the histological process. Future work may concentrate on more homogeneous material in order to derive sound speed data for separate components. Nevertheless, this study increases the known data ranges of the individual components within a plaque. This information may be used help to assess the mechanical properties and structural integrity and its associated vulnerability or risk of embolization in future diagnostic ultrasound techniques.

Cardiac function in 10-year-old twins following different fetal therapies for twin-twin transfusion syndrome.

OBJECTIVES: To compare cardiac function at 10 years of age in four groups of monochorionic diamniotic (MCDA) twin pairs: uncomplicated MCDA twins (n = 6) (Group 1); twins that had had twin-twin transfusion syndrome (TTTS) managed by amnioreduction (TTTS-amnio, n = 9) (Group 2) or laser photocoagulation (TTTS-laser, n = 10) (Group 3); and dichorionic diamniotic controls (DCDA, n = 6) (Group 4). METHODS: Echocardiograms optimizing apical four-chamber and short-axis left ventricular views were stored for offline speckle-tracking analysis, blinded to twin type. Myocardial long-axis shortening and lengthening velocities were measured using pulsed Doppler ultrasound at the cardiac base. M-mode measurements of fractional shortening (short axis) and maximal excursion of the atrioventricular annulus (four-chamber) were recorded. Syngo Vector Velocity Imaging software tracked left ventricular myocardial motion offline to produce free wall strain, strain rate and rotation. Intertwin pair and group differences were investigated using ANOVA. RESULTS: Cardiac measurements were within the normal ranges for 10-year-olds. No significant within-twin-pair and intergroup differences were found in current size, heart rates, strain or strain rate. Compared to DCDA controls, TTTS twins showed less cardiac rotation (TTTS-laser, P < 0.001 and TTTS-amnio, P = 0.054) with significant intertwin reduction in the ex-recipient (TTTS-amnio, P = 0.006) and larger MCDA twins (P = 0.027) compared with their cotwins. A similar pattern was seen in left ventricular early diastolic mitral valve tissue velocity (MVE') in all monochorionic groups, but only achieving significance in TTTS-amnio twins (P = 0.037). Intrapair differences in rotation and MVE' were significantly different following treatment at Quintero stages III or IV. CONCLUSIONS: Within-twin-pair patterns of left ventricular rotation and diastolic function differ at 10 years of age in ex-recipients of TTTS twins treated with amnioreduction compared with those treated by laser photocoagulation and controls. .

Vascular programming in twins: the effects of chorionicity and fetal therapy for twin-to-twin transfusion syndrome.

We assessed vascular programming in genetically identical monochorionic twin pairs with twin-to-twin transfusion syndrome (TTTS) treated differently in utero by serial amnioreduction or fetal laser arterial photocoagulation. This case-control study re-assessed four twin groups at median 11 years comprising 20 pairs of monochorionic diamniotic twins: nine treated by amnioreduction (TTTS-amnio) and eleven by laser (TTTS-laser) with seven monochorionic and six dichorionic control pairs. Outcome measures were current blood pressure (BP), brachio-radial arterial stiffness derived from pulse wave velocity (PWV), resting microcirculation (Flux) and response to heating and post-occlusive reactive hyperaemia measured using laser Doppler. Potential confounders [PWV and BP at first study, current height, weight, heart rate and twin type (ex-recipient, ex-donor or heavier/lighter of pair)] were accounted for by Mixed Linear Models statistical methodology. PWV dichorionic > monochorionic (P = 0.024); systolic and diastolic BP dichorionic > TTTS-amnio and TTTS-laser (P = 0.004, P = 0.02 and P = 0.005, P = 0.02, respectively). Within-twin pair pattern of PWV discordance was similar in laser treated and dichorionic controls (heavier-born > lighter), opposite to TTTS-amnio and monochorionic controls. Flux monochorionic > dichorionic (P = 0.044) and heavier > lighter-born (P = 0.024). TTTS-laser and dichorionic diamniotic showed greatest hyperaemic responses (dichorionic > TTTS-amnio or monochorionic controls (P = 0.007, P = 0.025). Hyperaemic responses were slower in heavier-born twins (P = 0.005). In summary, monochorionic twins had lower BP, arterial stiffness and increased resting vasodilatation than dichorionic twins implying shared fetal circulation affects vascular development. Vascular responses in laser-TTTS were similar to dichorionic and opposite to TTTS-amnio suggesting a lasting effect of fetal therapy on vascular health.

Pretreatment frontal EEG and changes in suicidal ideation during SSRI treatment in major depressive disorder.

OBJECTIVE: We investigated frontal quantitative EEG (QEEG) as predictor of changes in suicidal ideation (SI) during SSRI treatment in major depressive disorder (MDD). METHOD: Eighty-two subjects meeting DSM-IV criteria for MDD entered an 8-week, prospective, open-label treatment with flexible dose SSRIs and completed at least 4 weeks of treatment. We assessed MDD severity with the 17-item Hamilton Depression Rating Scale (HAM-D-17); change in SI was measured with HAM-D item no. 3. We recorded four-channel EEGs (F7-Fpz, F8-Fpz, A1-Fpz, A2-Fpz) before treatment. RESULTS: During the first 4 weeks of treatment 9 (11%) subjects experienced worsening SI. Left-right asymmetry of combined theta + alpha power correlated significantly with change in SI from baseline, even when adjusting for changes in depression severity (HAM-D-17) and for the SSRI utilized. CONCLUSION: Frontal QEEG parameters before treatment may predict worsening SI during SSRI treatment in MDD.

Ageing of the conduit arteries.

Conduit arteries become stiffer with age due to alterations in their morphology and the composition of the their major structural proteins, elastin and collagen. The elastic lamellae undergo fragmentation and thinning, leading to ectasia and a gradual transfer of mechanical load to collagen, which is 100-1000 times stiffer than elastin. Possible causes of this fragmentation are mechanical (fatigue failure) or enzymatic (driven by matrix metallo proteinases (MMP) activity), both of which may have genetic or environmental origins (fetal programming). Furthermore, the remaining elastin itself becomes stiffer, owing to calcification and the formation of cross-links due to advanced glycation end-products (AGEs), a process that affects collagen even more strongly. These changes are accelerated in the presence of disease such as hypertension, diabetes and uraemia and may be exacerbated locally by atherosclerosis. Raised MMP activity, calcification and impaired endothelial function are also associated with a high level of plasma homocysteine, which itself increases with age. Impaired endothelial function leads to increased resting vascular smooth muscle tone and further increases in vascular stiffness and mean and/or pulse pressure. The effect of increased stiffness, whatever its underlying causes, is to reduce the reservoir/buffering function of the conduit arteries near the heart and to increase pulse wave velocity, both of which increase systolic and pulse pressure. These determine the peak load on the heart and the vascular system as a whole, the breakdown of which, like that of any machine, depends more on the maximum loads they must bear than on their average. Reversing or stabilising the increased arterial stiffness associated with age and disease by targeting any or all of its causes provides a number of promising new approaches to the treatment of systolic hypertension and its sequelae, the main causes of mortality and morbidity in the developed world.

Rates of lifetime suicide attempt and rates of lifetime major depression in different ethnic groups in the United States.

OBJECTIVE: Rates of major depression and suicide vary across ethnic groups within the US. This also may be true of suicide attempts. METHOD: Data on lifetime suicidal behavior and major depression among Mexican American, Cuban American, and Puerto Rican adults who participated in the Hispanic Health and Nutrition Epidemiologic Survey were pooled with Epidemiological Catchment Area Study data for Blacks, Whites and Hispanics. RESULTS: Rates of major depression ranged from 9.3 (Puerto Ricans) to 3.24% (Cuban Americans). Puerto Ricans and whites had the highest rates of depression. Similarly, suicide attempt rates ranged from 9.1% for Puerto Ricans to 1.9% for Cuban Americans. Puerto Ricans had higher suicide attempt rates compared with other groups. CONCLUSION: This study underscores that there are differences between Hispanic ethnic groups. The impact of the migration process, socioeconomic status, and acculturation may underlie differences in major depression and suicide attempt rates across ethnic groups.

Residual strains in conduit arteries.

Residual strains and stresses are those that exist in a body when all external loads are removed. Residual strains in arteries can be characterized by the opening angle of the sector-like cross-section which arises when an unloaded ring segment is radially cut. A review of experimental methods for measuring residual strains and the main results about the variation of the opening angle with arterial localization, age, smooth muscle activity, mechanical environment and certain vascular pathologies are presented and discussed. It is shown that, in addition to their well-established ability to homogenize the stress field in the arterial wall, residual strains make arteries more compliant and thereby improve their performance as elastic reservoirs and ensure more effective local control of the arterial lumen by smooth muscle cells. Finally, evidence that, in some cases, residual strains remain in arteries even after they have been cut radially is discussed.

A hypothesis about a mechanism for the programming of blood pressure and vascular disease in early life.

1. There is now a great deal of evidence that people whose weight at birth was low tend to have higher blood pressure and increased risk of death from cardiovascular disease as adults. 2. We argue that, in fetuses whose growth is impaired, synthesis of elastin in the walls of the aorta and large arteries is deficient and that this deficiency leads to permanent changes in the mechanical properties of these vessels. 3. Over a lifetime, such changes could predispose an individual to higher blood pressure and cardiovascular disease.

The association between head injuries and psychiatric disorders: findings from the New Haven NIMH Epidemiologic Catchment Area Study.

PRIMARY OBJECTIVE: To determine the association of report of any history of head injury with loss of consciousness or confusion and a lifetime diagnosis of psychiatric disorder in a general population. RESEARCH DESIGN: A probability sample of adults from the New Haven portion of the NIMH Epidemiologic Catchment Area programme were administered standardized and validated structured interviews. The main outcome measures were lifetime prevalence of psychiatric disorders and suicide attempt in individuals with and without a history of traumatic brain injury. MAIN OUTCOMES AND RESULTS: Among 5034 individuals interviewed, 361 admitted to a history of severe brain trauma with loss of consciousness or confusion (weighted rate of 8.5/100). When controlling for sociodemographic factors, quality of life indicators and alcohol use, risk was increased for major depression, dysthymia, panic disorder, OCD, phobic disorder and drug abuse/dependence. In addition, lifetime risk of suicide attempt was greater in those who had suffered head injury. CONCLUSION: Individuals with a history of traumatic brain injury have significantly higher occurrence for psychiatric disorders and suicide attempts in comparison with those without head injury and have a poorer quality of life. Future studies should examine the nature of this relationship, focusing on the severity of the brain injury and the temporal contiguity of the brain injury and psychiatric disorder.

Ethnic and sex differences in suicide rates relative to major depression in the United States.

OBJECTIVE: Suicide rates differ between ethnic groups in the United States. Since suicide is commonly associated with a mood disorder, the authors compared suicide rates relative to depression rates in five ethnic groups in the United States. METHOD: Rates of major depression were generated from the Epidemiologic Catchment Area study and the Hispanic Health and Nutrition Epidemiologic Survey. Sociodemographic effects were determined by examining depression rates for respondents who were separated or divorced, earning low incomes, or not working for pay. The survey data were analyzed with age and sex standardization to generate 1-year prevalence rates of major depression. The depression rates of the different ethnic groups were compared and were examined in relation to suicide rates. RESULTS: The 1-year prevalence rates of major depression were 3.6% for whites, 3.5% for blacks, 2.8% for Mexican Americans, 2.5% for Cuban Americans, and 6.9% for Puerto Ricans. Compared to the rate for whites, the rate of depression was significantly higher in Puerto Ricans and significantly lower in Mexican Americans. Relative to the depression rates, the annual suicide rates were higher for males than for females. Mexican American and Puerto Rican males had lower relative suicide rates than white males. CONCLUSIONS: Identifying reasons for differences in suicide rates relative to depression among ethnic groups and between males and females may suggest interventions to reduce suicide rates. Some possibilities are that depression differs in form or severity or that unidentified factors protect against suicide in different subgroups.

Psychosocial and risk behavior correlates of youth suicide attempts and suicidal ideation.

OBJECTIVE: To identify the independent psychosocial and risk behavior correlates of suicidal ideation and attempts. METHOD: The relationships between suicidal ideation or attempts and family environment, subject characteristics, and various risk behaviors were examined among 1,285 randomly selected children and adolescents, aged 9 through 17 years, of whom 42 (3.3%) had attempted suicide and 67 (5.2%) had expressed suicidal ideation only. The youths and their parents were enumerated and interviewed between December 1991 and July 1992 as part of the NIMH Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study. RESULTS: Compared with subjects with suicidal ideation only, attempters were significantly more likely to have experienced stressful life events, to have become sexually active, to have smoked more than one cigarette daily, and to have a history of ever having smoked marijuana. After adjusting for sociodemographic characteristics, a statistically significant association was found between suicidal ideation or attempt and stressful life events, poor family environment, parental psychiatric history, low parental monitoring, low instrumental and social competence, sexual activity, marijuana use, recent drunkenness, current smoking, and physical fighting. Even after further adjusting for the presence of a mood, anxiety, or disruptive disorder, a significant association persisted between suicidal ideation or attempts and poor family environment, low parental monitoring, low youth instrumental competence, sexual activity, recent drunkenness, current smoking, and physical fighting. CONCLUSION: Low parental monitoring and risk behaviors (such as smoking, physical fighting, alcohol intoxication, and sexual activity) are independently associated with increased risk of suicidal ideation and attempts, even after adjusting for the presence of psychiatric disorder and sociodemographic variables.

Assessing the homogeneity of the elastic properties and composition of the pig aortic media.

Most previous studies of arterial wall elasticity and rheology have assumed that the properties of the wall are uniform across the thickness of the media and, therefore, that the relationship between stress and strain may be described by a constitutive equation based on a single strain energy function. The few studies where this assumption has been questioned, focussed on differences between the adventitia and the media rather than on differences within the media itself. Here, we report in vitro elasticity and residual strain measurements performed separately on the inner and outer half of the pig aortic media, together with a histomorphometric assessment of the radial distribution of elastin, collagen and smooth muscle cell numbers. Although we found that the pressure-diameter relationships of the two halves were dissimilar, when allowance was made for their different unloaded dimensions, their material properties agreed closely, a result in keeping with the observed uniform radial distribution of scleroprotein and vascular smooth muscle. We also found a difference in the opening angle (which is often taken as a measure of residual strain) between the inner and outer medial halves. However, strain analysis showed that the opening angle is an extremely sensitive measure of residual strain and that the difference in the actual magnitudes of residual strain between the two halves of the media was small. We conclude that the media of the porcine thoracic aorta has similar elastic properties throughout its thickness and that this uniformity is matched by a uniform distribution of matrix protein and vascular smooth muscle cells. Furthermore, the distribution of strain in the media can adequately be described by a single-layer model with uniform elastic properties throughout its thickness.

Psychiatric disorders in the relatives of probands with prepubertal-onset or adolescent-onset major depression.

OBJECTIVE: To determine whether the familial risk of major depressive disorder (MDD) varies with either onset, recurrence, or continuity of MDD in adulthood in prepubertal- compared with adolescent-onset probands. METHOD: Seventy-six prepubertal-onset MDD, 59 adolescent-onset MDD, and 78 never psychiatrically ill probands were assessed as children or adolescents and were evaluated 10 to 15 years later as adults, by an independent team that was blind to the initial diagnoses. At follow-up, psychiatric disorders among 731 of their first-degree relatives were assessed using direct interviews and family history methods by investigators who were blind to the clinical status of the probands. RESULTS: Both prepubertal- and adolescent-onset MDD were significantly associated with a family history of MDD. The familial rates of MDD and other psychopathology did not vary between the 2 groups. For prepubertal-onset MDD, family history was significantly associated with recurrence and nonsignificantly associated (trend) with continuity into adulthood. In contrast, there was no association between a family history of MDD and either recurrence or continuity into adulthood of adolescent-onset MDD. CONCLUSIONS: Prepubertal- and adolescent-onset MDD are both associated with a family history of MDD, but only in prepubertal-onset MDD is familial loading associated with recurrence and continuity of MDD into adulthood.

Religiosity and substance use and abuse among adolescents in the National Comorbidity Survey.

OBJECTIVE: To replicate previous findings among adults of an inverse association between religiosity and substance use among a nationally representative sample of adolescents. METHOD: Subjects were 676 (328 female and 348 male) adolescents in the National Comorbidity Survey who were assessed for substance use and abuse with the Composite International Diagnostic Interview. Religiosity was assessed through affiliation with religious denomination and through response to 7 questions concerning belief and practice. RESULTS: Confirmatory factor analyses replicated in adolescents the 2 religiosity factors of personal devotion and personal conservatism previously identified by Kendler among adults, although the 2 factors were more highly correlated in adolescents than in adults. Personal devotion (a personal relationship with the Divine) and affiliation with more fundamentalist religious denominations were inversely associated with substance use and substance dependence or abuse across a range of substances (alcohol, marijuana, cocaine, or any contraband drug). Personal conservatism (a personal commitment to teaching and living according to creed) was inversely associated with use of alcohol only. CONCLUSION: Low levels of religiosity may be associated with adolescent onset of substance use and abuse.

Risk behavior in a community sample of children and adolescents.

OBJECTIVES: First, to investigate whether there is covariation between risk behaviors, including suicidality, in a community probability sample of children and adolescents; and second, to investigate whether risk behavior is associated with selected potential correlates. METHOD: A sample of 9- to 17-year-old youths (N = 1,285) and their caretakers were interviewed in the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study. The risk behaviors were marijuana smoking, alcohol use, intercourse, fighting, cigarette smoking, and suicidal ideation/attempts. Relationships between the risk behaviors were described using odds ratios. Linear regression analyses of an index of risk behavior on the selected potential correlates of risk behavior were conducted. RESULTS: There were significant relationships between all pairs of risk behaviors. The score on the index of risk behavior was associated with stressors, lack of resources, family psychiatric disorder, psychopathology, and functional impairment. CONCLUSIONS: Clinicians should be alerted to the possibility of risk behaviors, especially in children and adolescents engaging in other risk behaviors and those with inadequate resources, stressors, functional impairment, or psychopathology.

Nonaffective psychosis after prenatal exposure to rubella.

OBJECTIVE: The authors' goal was to investigate the suggestion of previous investigations that prenatal viral exposures might increase the later risk of psychotic disorders. METHOD: They conducted a follow-up study in young adulthood of a birth cohort that was previously documented, by clinical examination and serological testing, to have in utero rubella exposure during the 1964 rubella epidemic. Data were also obtained from an unexposed birth cohort and from the Epidemiological Catchment Area survey. Young adult subjects were administered a standard psychiatric diagnostic interview. The authors compared the proportions of subjects with nonaffective psychosis in the exposed and unexposed cohorts. RESULTS: The rubella-exposed subjects, most of whom were exposed in the first trimester, demonstrated a substantially greater risk for nonaffective psychosis than the subjects who were not exposed to rubella (relative risk=5.2). CONCLUSIONS: There is an association between clinically and serologically diagnosed prenatal viral infection and nonaffective psychosis in adulthood.

Improving vascular grafts: the importance of mechanical and haemodynamic properties.

In the last 40 years, as techniques and materials have improved, the success rate of vascular prostheses with a diameter greater than 6mm has risen steadily, 5-year survival rates exceeding 95% in most centres. With smaller grafts no comparable improvement has occurred, the majority failing within 5 years, usually as a result of intimal hyperplasia and, ultimately atherosclerosis, in and around the downstream anastomosis. Clinical evidence suggests that the patency rates of small grafts are improved by matching the elastic properties of the graft to that of the artery into which it is placed. Although there is little reliable evidence that 'elastic mismatch' per se is the cause of intimal hyperplasia, it is generally accepted that mechanical factors are important in its genesis. These include disturbed flow at the anastomosis leading to fluctuations in shear stress at the endothelium (a known cause of intimal hyperplasia in normal arteries), injury due to suturing and stress concentration at the anastomosis. Few suitable materials or techniques have yet been developed to improve the long-term survival rates of small grafts. Recent advances in tissue engineering in which prostheses are manufactured by culturing vascular smooth muscle cells on a tubular scaffold of biodegradable polymer may ultimately make it possible to manufacture biologically and haemodynamically compatible grafts with diameters as small as 1mm.