The root meristem is shaped by brassinosteroid control of cell geometry

Growth extent and direction determine cell and whole-organ architecture. How they are spatio-temporally modulated to control size and shape is not well known. Here we tackled this question by studying the effect of brassinosteroid (BR) signalling on the structure of the root meristem. Quantification of the three-dimensional geometry of thousands of individual meristematic cells across different tissue types showed that the modulation of BR signalling yields distinct changes in growth rate and anisotropy, which affects the time that cells spend in the meristem and has a strong impact on the final root form. By contrast, the hormone effect on cell volume was minor, establishing cell volume as invariant to the effect of BR. Thus, BR has the highest effect on cell shape and growth anisotropy, regulating the overall longitudinal and radial growth of the meristem, while maintaining a coherent distribution of cell sizes. Moving from single-cell quantification to the whole organ, we developed a computational model of radial growth. The simulation demonstrates how differential BR-regulated growth between the inner and outer tissues shapes the meristem and thus explains the non-intuitive outcomes of tissue-specific perturbation of BR signalling. The combined experimental data and simulation suggest that the inner and outer tissues have distinct but coordinated roles in growth regulation.

A residual heat compensation based scan strategy for powder bed fusion additive manufacturing

Typical scan strategies for laser powder bed fusion (LPBF) additive manufacturing systems apply a constant laser power and scan speed. Localized preheating from adjacent scan paths (residual heat) result in inconsistent melt-pool morphology. A new control approach is proposed which compensates the residual heat through laser power adjustment. A model called residual heat factor (RHF) is developed to 'quantify' the residual heat effect, and laser power is controlled proportional to this RHF. Experiments are conducted on a custom-controlled LPBF testbed on nickel-alloy (IN625) bare plate, and the effects of this unique scan strategy are investigated by in-situ melt-pool monitoring.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Associations of baseline characteristics with evolution of eGFR in a referred chronic kidney disease cohort

BACKGROUND

Currently, most chronic kidney disease (CKD) classifications identify patients at different stages of CKD but do not identify risk of progression or adverse outcome. This analysis aims to describe associations between baseline characteristics and the evolution of estimated glomerular filtration rate (eGFR) and identify threshold values for clinical parameters that maximally discriminate progression to renal replacement therapy (RRT) in a referred cohort of patients with CKD stages 3-5.

DESIGN AND METHODS

A longitudinal mixed-effect model was used to determine annualized estimated change in eGFR and classification tree analysis to identify threshold values that maximally discriminate progression to RRT.

RESULTS

A total of 1316 patients were available for analysis with median follow-up of 33 months (interquartile range 20-60). Mixed model analysis suggested that the underlying diagnoses of autosomal dominant polycystic kidney disease and diabetic nephropathy exhibited on average a 2.7 (0.3) and 0.7 (0.3) ml/min/year faster rate of decline in eGFR, respectively, compared to those patients with biopsy-proven glomerulonephritis. In the regression tree analysis, we attempted to identify threshold values for clinical parameters that maximally discriminate progression to RRT. eGFR ≤24 ml/min was the first ranked discriminator, diastolic blood pressure appeared in the second and fourth rounds, eGFR appeared again in the third round together with cholesterol and systolic blood pressure, with basal metabolic index in the fourth.

CONCLUSION

This analysis highlights risk factors for progressive kidney disease and demonstrates the variability in evolution of eGFR across the cohort as well as the importance of underlying renal disease type on the progression of CKD.

The heparin-binding protein interactome in pancreatic diseases

BACKGROUND

The cellular microenvironment plays an important role in the regulation of homoeostasis and is a source of potential biomarkers and drug targets. In a genome-wide analysis the extracellular proteins that bind to heparin (HBPs) have been shown to form highly modular and interconnected extracellular protein regulatory networks. Using a systems biology approach, we have investigated the role of HBP networks in the normal pancreas and pancreatic digestive diseases.

METHODS

Lists of mRNAs encoding for HBPs associated with the normal pancreas (NP), acute pancreatitis (AP), chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) were obtained using public databases and publications. Networks of the putative protein interactomes derived from mRNA expression data of HBPs were built and analysed using cluster analysis, gene ontology term enrichment and canonical pathways analysis.

RESULTS

The extracellular heparin-binding putative protein interactomes in the pancreas were better connected than their non heparin-binding counterparts, having higher clustering coefficients in the normal pancreas (0.273), acute pancreatitis (0.457), chronic pancreatitis (0.329) and pancreatic ductal adenocarcinoma (0.269). 'Hepatic Fibrosis/Hepatic Stellate Cell Activation' appears to be a significant canonical pathway in pancreatic homoeostasis in health and disease with a large number of important HBPs.

CONCLUSIONS

Our analyses clearly demonstrate that HBPs form disease-specific and highly connected networks that can be explored for potential biomarkers and as collective drug targets via the modification of heparin binding properties.

Major themes for 2011 in cardiovascular anesthesia and intensive care

The past year has witnessed major advances in of cardiovascular anesthesia and intensive care. Perioperative interventions such as anesthetic design, inotrope choice, glycemic therapy, blood management, and noninvasive ventilation have significant potential to enhance perioperative outcomes even further.The major theme for 2011 is the international consensus conference that focused on ancillary interventions likely to reduce mortality in cardiac anesthesia and intensive care. This landmark conference prioritized volatile anesthetics, levosimendan, and insulin therapy for their promising life-saving perioperative potential. Although extensive evidence has demonstrated the cardioprotective effects of volatile anesthetics, levosimendan as well as glucose, insulin and potassium therapy, the clinical relevance of these beneficial effects remains to be fully elucidated. Furthermore, controversy still persists about how tight perioperative glucose control should be in adult cardiac surgery because of the risk of hypoglycemia.A second major theme in 2011 has been perioperative hemostasis with the release of multispecialty guidelines. Furthermore, hemostatic agents such as recombinant factor VIIa and tranexamic acid have been studied intensively, even in the setting of major non-cardiac surgery. This review then highlights the remaining two major themes for 2011, namely the expanding role of noninvasive ventilation in our specialty and the formation of the Roland Hetzer International Cardiothoracic and Vascular Surgery Society.In conclusion, it is time for large adequately powered multicenter trials to test whether prioritized perioperative interventions truly reduce mortality and morbidity in cardiac surgical patients. This essential paradigm shift represents a major clinical opportunity for the global cardiovascular anesthesia and critical care community.

Risk factors associated with major cerebrovascular complications after intracranial stenting

BACKGROUND

There are limited data on the relationship between patient and site characteristics and clinical outcomes after intracranial stenting.

METHODS

We performed a multivariable analysis that correlated patient and site characteristics with the occurrence of the primary endpoint (any stroke or death within 30 days of stenting or stroke in the territory of the stented artery beyond 30 days) in 160 patients enrolled in this stenting registry. All patients presented with an ischemic stroke, TIA, or other cerebral ischemic event (e.g., vertebrobasilar insufficiency) in the territory of a suspected 50-99% stenosis of a major intracranial artery while on antithrombotic therapy.

RESULTS

Cerebral angiography confirmed that 99% (158/160) of patients had a 50-99% stenosis. In multivariable analysis, the primary endpoint was associated with posterior circulation stenosis (vs anterior circulation) (hazard ratio [HR] 3.4, 95% confidence interval [CI] 1.2-9.3, p = 0.018), stenting at low enrollment sites (< 10 patients each) (vs high enrollment site) (HR 2.8, 95% CI 1.1-7.6, p = 0.038), < or = 10 days from qualifying event to stenting (vs > or = 10 days) (HR 2.7, 95% CI 1.0-7.8, p = 0.058), and stroke as a qualifying event (vs TIA/other) (HR 3.2, 95% CI 0.9-11.2, p = 0.064). There was no significant difference in the primary endpoint based on age, gender, race, or percent stenosis (50-69% vs 70-99%).

CONCLUSIONS

Major cerebrovascular complications after intracranial stenting may be associated with posterior circulation stenosis, low volume sites, stenting soon after a qualifying event, and stroke as the qualifying event. These factors will need to be monitored in future trials of intracranial stenting.

The NIH registry on use of the Wingspan stent for symptomatic 70-99% intracranial arterial stenosis

BACKGROUND

The Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial showed that patients with symptomatic 70% to 99% intracranial arterial stenosis are at particularly high risk of ipsilateral stroke on medical therapy: 18% at 1 year (95% CI = 3% to 24%). The Wingspan intracranial stent is another therapeutic option but there are limited data on the technical success of stenting and outcome of patients with 70% to 99% stenosis treated with a Wingspan stent.

METHODS

Sixteen medical centers enrolled consecutive patients treated with a Wingspan stent in this registry between November 2005 and October 2006. Data on stenting indication, severity of stenosis, technical success (stent placement across the target lesion with <50% residual stenosis), follow-up angiography, and outcome were collected.

RESULTS

A total of 129 patients with symptomatic 70% to 99% intracranial stenosis were enrolled. The technical success rate was 96.7%. The mean pre and post-stent stenoses were 82% and 20%. The frequency of any stroke, intracerebral hemorrhage, or death within 30 days or ipsilateral stroke beyond 30 days was 14.0% at 6 months (95% CI = 8.7% to 22.1%). The frequency of >or=50% restenosis on follow-up angiography was 13/52 (25%).

CONCLUSION

The use of a Wingspan stent in patients with severe intracranial stenosis is relatively safe with high rate of technical success with moderately high rate of restenosis. Comparison of the event rates in high-risk patients in Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) vs this registry do not rule out either that stenting could be associated with a substantial relative risk reduction (e.g., 50%) or has no advantage compared with medical therapy. A randomized trial comparing stenting with medical therapy is needed.

Unusual cause of a perforated stomach

A case of gastric perforation 2 months following insertion of a gastric balloon is reported. The literature is reviewed regarding the complications and success rates inherent in such balloon devices. This is the first case report of an intra-gastric balloon causing gastric perforation.

End-stage renal disease in Indo-Asians in the North-West of England

BACKGROUND

The incidence of end-stage renal disease (ESRD) in England is increasing. There is a higher incidence of ESRD in British Indo-Asians than in the White population.

AIM

To determine to what degree the increasing demand for renal replacement therapy in the UK is due to Indo-Asian patients. To study the presentation to renal services of Indo-Asian patients with ESRD and report any inequalities in initial treatment of Indo-Asian patients with ESRD compared to their White counterparts.

DESIGN

Prospective, inception cohort study.

METHODS

Consecutive adult patients with ESRD who started renal replacement therapy between 1 April 2000 and 31 December 2001 in all 14 renal units serving an area from North Cheshire to South Cumbria, including Greater Manchester and Lancashire, were recruited and interviewed.

RESULTS

Of the 578 patients, 9.5% were Indo-Asian. The annual acceptance rate for renal replacement therapy was 342 per million population in Indo-Asians, compared with 91 per million population in the White population ( p < 0.001). Indo-Asian patients with ESRD were younger (median age 51 years vs. 60 yrs, p = 0.006) and more socially deprived (81% vs. 36.5% in the 5th Carstairs quintile, p < 0.001). A greater proportion of Indo-Asian patients with ESRD presented late to specialist renal services (31% vs. 19%, p = 0.03). Once adjusting for their younger age, atherosclerotic renovascular disease and/or hypertensive nephropathy was more prevalent in Indo-Asian patients (OR 4.9; p = 0.03). There was no difference in the initial mode of maintenance dialysis or the perception of choice the patients felt they had, based on their ethnicity.

DISCUSSION

There is a silent epidemic of ESRD in Indo-Asian patients in the North-West, possibly vascular in aetiology, in which specialist intervention is late. This suggests that Indo-Asian patients should be prioritized for early intervention strategies to reduce the burden of ESRD.

Defining small bowel strictures

BACKGROUND

Strictures of the intestine can be difficult to detect despite current radiological techniques.

AIM

To review our experience with a new Foley catheter technique.

METHOD

Three cases are reviewed in which a Foley catheter was used to identify a fibrous stricture.

RESULTS

A Foley catheter with an inflated 10ml balloon inserted through an enterotomy successfully identified the site of stricture in three cases of fibrous stricture obstruction.

CONCLUSION

A Foley catheter inserted through an enterotomy is a useful method of identifying fibrous strictures.

Imaging of cerebral and brain stem amyloidomas

CNS amyloidomas are rare. We describe a 51-year-old man with isolated amyloidomas in the cerebral white matter and in the pons. CT and MR imaging showed a heterogeneous, enhancing mass in the deep cerebral white matter. A second, much smaller linear serpiginous lesion was present in the pons.

Single- versus multi-detector row CT of the brain: quality assessment

PURPOSE

To assess the quality of brain computed tomographic (CT) studies obtained with a four-channel multi-detector row CT scanner compared with those obtained with a single-detector row CT scanner.

MATERIALS AND METHODS

Forty-seven patients referred for brain CT were imaged with both single- and multi-detector row scanners. Single-detector row CT images were acquired by using a 5-mm-collimated beam in the transverse mode. Multi-detector row CT images were acquired in four simultaneous 2.5-mm-thick sections, which were combined in projection space to create two contiguous 5-mm-thick sections. Two neuroradiologists blinded to the acquisition technique independently evaluated the CT image pairs, which were presented in a stacked mode on two adjacent monitors. Each study was graded by using a five-point scale for posterior fossa artifact, overall image quality, and overall preference.

RESULTS

Multi-detector row CT studies were acquired 1.8 times faster than single-detector row CT studies (0.92 vs 0.52 section per second). Multi-detector row CT posterior fossa artifact was less than single-detector row CT posterior fossa artifact in 87 (93%) of 94 studies. Overall preference was expressed for multi-detector row CT in 84 (89%) of 94 studies. The differences in mean posterior fossa artifact scores (P <.001) and mean overall image quality scores (P =.001) were significant.

CONCLUSION

Brain CT images obtained with multi-detector row CT resulted in significantly less posterior fossa artifact and were preferred to single-detector row CT images.

It's just different in the country: postnatal depression and group therapy in a rural setting

The treatment of postnatal depression (PND) via group therapy is an accepted practice in Sydney and other metropolitan areas throughout Australia. This article analyses the difficulties faced in the importation of this urban-developed treatment model into a rural setting. In 1995, this program was established in a major rural centre of New South Wales (NSW) and drew participants from the regional centre, surrounding rural properties, towns and villages. Participation in the program resulted in significant lowering or absences of depressive episodes following treatment. But beyond this significant aspect of a positive response to this treatment program is a fascinating aspect of differences between the rural and urban groups in this population. The differences occurred in group formation, group process and attitudes of the participants. We would suggest that group leaders in rural PND programs face more resistance to the idea of groups for therapeutic intervention, need to draw different lines between personal and professional boundaries from their urban counterparts and are confronted with participants who adhere more strongly to the prevailing mythology of motherhood. This mythology may increase the likelihood and intensity of postnatal depression and cause greater resistance to cognitive restructuring skills, which are essential for challenging thoughts that enhance depression.

Infratentorial traumatic brain hemorrhage: may outcome be predicted by initial GCS?

BACKGROUND

Overall prognosis of nonpenetrating traumatic brain hemorrhage may be predicted by neurologic function days after insult. The relationship between immediate function and outcome has not been examined for infratentorial traumatic brain hemmorhage (iTBH) identified on computed tomographic (CT) scan. Given the severity of brain stem injury, it is conceivable that immediate function may be predictive.

METHODS

A retrospective review of 1,500 brain injuries occurring at our institution identified 18 patients (1.2%) with iTBH on CT scan (eight brain stem, five cerebellum, five both). Demographics, supratentorial injuries, and outcome at 6 months (Glasgow Outcome Scale) were recorded.

RESULTS

Initial Glasgow Coma Scale (GCS) in 11 patients was less than 5 (group I). Seven patients had GCS scores greater than or equal to 6 (group II). Nine patients in group I either died or were vegetative. In group II, one died; none were vegetative (p < 0.02). Regression analysis demonstrated a strong correlation between initial GCS and Glasgow Outcome Scale scores at 6 months for all patients (p < 0.001).

CONCLUSION

We conclude that initial GCS score may be predictive of long-term outcome in patients with CT scan evidence of iTBH-a relationship to be explored further for prognostic information.

The cannabinoid system and cytokine network

Many advances have been made in the last few years concerning our understanding of the receptors and ligands composing the cannabinoid system. Likewise, the science surrounding cytokine biology has advanced enabling us to measure these proteins more precisely as well as understand and interpret the meaning of changes in their levels. Scientists wishing to study the health consequences of smoking marijuana as well as understand the possible role of endogenous cannabimimetic ligands in immune regulation have continued to study the influence of these substances on the regulation and development of the cytokine network. Research has shown that two major cannabinoid receptor subtypes exist and that subtype 1 (CB1) is expressed primarily in the brain whereas subtype 2 (CB2) is expressed primarily in the periphery. A variety of ligands for these receptors based on the cannabinoid structure have been synthesized and studied as well as low affinity compounds, noncannabinoid ligands, and endogenous ligands derived from fatty acid eicosanoids. Highly selective receptor antagonists have also been introduced and studied. Synthetic, low affinity ligands such as (+)-HU-211 and DMH-11C have been shown to cause anti-inflammatory effects possibly through inhibiting the production and action of TNF-alpha and other acute phase cytokines. In addition, suppression of TNF and other cytokines such as GM-CSF, IL-6, IFNgamma, and IL-12 has also been seen following exposure to high affinity and psychoactive ligands such as marijuana and THC. However, some of these ligands have also been shown to increase rather than decrease interleukins such as IL-1, IL-4, IL-10, and IL-6, cytokines such as TNF-alpha, and chemokines such as IL-8, MIP-1, and RANTES. The endogenous ligand, anandamide, has been shown in culture to either suppress the proliferation response to prolactin or enhance the response to cytokines such as IL-3 and IL-6. This eicosanoid has also been shown to increase the production of interleukins and other cytokines. Cannabinoid receptors have been shown to be involved in some but not all of these effects. It is clear that psychoactive and nonpsychoactive compounds have demonstrated effects in vivo and in vitro on the production and function of a variety of cytokines. Depending upon the model system, these effects are often conflicting, and the involvement of cannabinoid receptors is unclear. However, enough evidence exists to suggest that the cannabinoid system significantly impacts the functioning of the cytokine network, and this association may provide clues to the mechanisms of certain immune diseases and form the basis for new immunotherapies.

The cannabinoid system and cytokine network

Many advances have been made in the last few years concerning our understanding of the receptors and ligands composing the cannabinoid system. Likewise, the science surrounding cytokine biology has advanced enabling us to measure these proteins more precisely as well as understand and interpret the meaning of changes in their levels. Scientists wishing to study the health consequences of smoking marijuana as well as understand the possible role of endogenous cannabimimetic ligands in immune regulation have continued to study the influence of these substances on the regulation and development of the cytokine network. Research has shown that two major cannabinoid receptor subtypes exist and that subtype 1 (CB1) is expressed primarily in the brain whereas subtype 2 (CB2) is expressed primarily in the periphery. A variety of ligands for these receptors based on the cannabinoid structure have been synthesized and studied as well as low affinity compounds, noncannabinoid ligands, and endogenous ligands derived from fatty acid eicosanoids. Highly selective receptor antagonists have also been introduced and studied. Synthetic, low affinity ligands such as (+)-HU-211 and DMH-11C have been shown to cause anti-inflammatory effects possibly through inhibiting the production and action of TNF-alpha and other acute phase cytokines. In addition, suppression of TNF and other cytokines such as GM-CSF, IL-6, IFNgamma, and IL-12 has also been seen following exposure to high affinity and psychoactive ligands such as marijuana and THC. However, some of these ligands have also been shown to increase rather than decrease interleukins such as IL-1, IL-4, IL-10, and IL-6, cytokines such as TNF-alpha, and chemokines such as IL-8, MIP-1, and RANTES. The endogenous ligand, anandamide, has been shown in culture to either suppress the proliferation response to prolactin or enhance the response to cytokines such as IL-3 and IL-6. This eicosanoid has also been shown to increase the production of interleukins and other cytokines. Cannabinoid receptors have been shown to be involved in some but not all of these effects. It is clear that psychoactive and nonpsychoactive compounds have demonstrated effects in vivo and in vitro on the production and function of a variety of cytokines. Depending upon the model system, these effects are often conflicting, and the involvement of cannabinoid receptors is unclear. However, enough evidence exists to suggest that the cannabinoid system significantly impacts the functioning of the cytokine network, and this association may provide clues to the mechanisms of certain immune diseases and form the basis for new immunotherapies.

Biomechanical analysis of the Rolled (RLD) leaf phenotype of maize

The pleiotropic effects of the Rld1-O/+ mutation of Zea mays (Poaceae) on leaf phenotype include a suppression of normal transverse unrolling, a reversed top/bottom epidermal polarity, and an apparently straighter longitudinal shape. According to engineering shell theory, there might be mechanical coupling between transverse and longitudinal habit, i.e., the leaf rolling itself might produce the longitudinal straightening. We tested this possibility with quantitative curvature measurements and mechanical uncoupling experiments. The contributions of elastic bending under self weight, mechanical coupling, and rest state of leaf parts to the longitudinal and transverse habit were assessed in Rld1-O/+ mutants and a population of sibling +/+ segregants. Elastic bending and curvature coupling are shown to be relatively unimportant. The Rld1-O/+ mutation is shown to alter not only the unrolling process, but also the developmental longitudinal curving in the growing leaf, leading to a straighter midrib and a rolled lamina. The Rld1-O/+ mutant is thus a suitable model to study the relation between tissue polarity and differential curvature development in the maize leaf. Since on the abaxial side of the leaf, more abundant sclerenchyma is found in +/+ than in Rld1-O/+, a gradient in sclerification may contribute to the development of midrib curvature.

Informed choice in genetic screening for thalassaemia during pregnancy: audit from a national confidential inquiry

OBJECTIVE

National audit of informed choice in antenatal screening for thalassaemia.

DESIGN

Audit from the UK Confidential Enquiry into Counselling for Genetic Disorders.

SETTING

Thalassaemia module of the UK Confidential Enquiry into Counselling for Genetic Disorders.

SUBJECTS

138 of 156 couples who had had a pregnancy affected by a major beta thalassaemia from 1990 to 1994.

MAIN OUTCOME MEASURES

How and when genetic risk was identified for each couple, and whether and when prenatal diagnosis was offered.

RESULTS

Risk was detected by screening before or during the first pregnancy in 49% (68/138) of couples and by diagnosis of an affected child in 28% (38/138) of couples. Prenatal diagnosis was offered in 69% (274/400) of pregnancies, ranging from 94% (122/130) for British Cypriots to 54% (80/149) for British Pakistanis and from 90% in the south east of England to 39% in the West Midlands. Uptake of prenatal diagnosis was 80% (216/274), ranging from 98% (117/120) among British Cypriots in either the first or second trimester to 73% (35/48) among British Pakistanis in the first trimester and 39% (11/28) in the second trimester. A demonstrable service failure occurred in 28% (110/400) of pregnancies, including 110 of 126 where prenatal diagnosis was not offered and 48 of 93 that ended with an affected liveborn infant.

CONCLUSION

Although antenatal screening and counselling for haemoglobin disorders are standard practices in the United Kingdom, they are delivered inadequately and inequitably. An explicit national policy is needed, aiming to make prenatal diagnosis in the first trimester available to all couples and including ongoing national audit.

Sonography, CT, and MR imaging: a prospective comparison of neonates with suspected intracranial ischemia and hemorrhage

BACKGROUND AND PURPOSE

Sonography, CT, and MR imaging are commonly used to screen for neonatal intracranial ischemia and hemorrhage, yet few studies have attempted to determine which imaging technique is best suited for this purpose. The goals of this study were to compare sonography with CT and MR imaging prospectively for the detection of intracranial ischemia or hemorrhage and to determine the prognostic value(s) of neuroimaging in neonates suspected of having hypoxic-ischemic injury (HII).

METHODS

Forty-seven neonates underwent CT (n = 26) or MR imaging (n = 24) or both (n = 3) within the first month of life for suspected HII. Sonography was performed according to research protocol within an average of 14.4 +/- 9.6 hours of CT or MR imaging. A kappa analysis of interobserver agreement was conducted using three independent observers. Infants underwent neurodevelopmental assessment at ages 2 months (n = 47) and 2 years (n = 26).

RESULTS

CT and MR imaging had significantly higher interobserver agreement (P < .001) for cortical HII and germinal matrix hemorrhage (GMH) (Grades I and II) compared with sonography. MR imaging and CT revealed 25 instances of HII compared with 13 identified by sonography. MR imaging and CT also revealed 10 instances of intraparenchymal hemorrhage (>1 cm, including Grade IV GMH) compared with sonography, which depicted five. The negative predictive values of neuroimaging, irrespective of technique used, were 53.3% and 58.8% at the 2-month and 2-year follow-up examinations, respectively.

CONCLUSION

CT and MR imaging have significantly better interobserver agreement for cortical HII and GMH/intraventricular hemorrhage and can reveal more instances of intraparenchymal hemorrhage compared with sonography. The absence of neuroimaging findings on sonograms, CT scans, or MR images does not rule out later neurologic dysfunction.

In vivo mammillary body volume deficits in amnesic and nonamnesic alcoholics

BACKGROUND

Neuropathological studies use the presence of mammillary body (MB) pathology as a cardinal, diagnostic feature of Wernicke's encephalopathy (WE) in neuropsychiatric diseases, most notably alcoholism. Although Korsakoffs Syndrome (KS), which is marked behaviorally by dense global amnesia, is a typical sequela of WE, it remains controversial whether these two conditions necessarily co-occur and whether MB pathology is therefore a diagnostic requisite for KS.

METHODS

We investigated these issues by examining, in vivo, 24 nonamnesic alcoholics (ALC), 5 amnesic alcoholics (KS), and 51 normal controls with three-dimensional MRI and memory testing. MB volume was determined from successive, 1 mm thick slices.

RESULTS

The ALC group had significantly smaller MB volumes bilaterally (mean = 54.5 +/- 22.0 mm3) than controls (mean = 66.3 +/- 17.1 mm3), and the KS group had even smaller MB volumes than the ALC group (mean = 20.7 +/- 14.8 mm3). Only 2 ALC patients met historical clinical criteria for past WE, and their MB volumes were well within range of the remaining 22 ALC patients. Although all five KS patients met historical clinical criteria for WE, three KS did not have accompanying dementia and had the same degree of MB volume loss as the ALC; the remaining two KS had accompanying dementia and MB volumes half the volume of the ALC group and of KS patients without dementia.

CONCLUSIONS

These findings provide volumetric in vivo evidence that: (1) MB volume deficits do occur in alcoholics without amnesia, although these deficits are not present in ail such alcoholics; (2) greater MB volume deficits are present in alcoholics with clinically detectable amnesia or dementia; (3) MB shrinkage is related to severity of cognitive and memory dysfunction, which suggests a continuum of MB pathology in chronic alcoholism to KS; and (4) the presence of WE in all of the KS patients and in the two ALC patients with the greatest long-term declarative memory deficit supports the possibility of an additional and unique pathology distinguishing nonamnesic and amnesic alcoholism.

National Confidential Enquiry into counselling for genetic disorders by non-geneticists: general recommendations and specific standards for improving care

OBJECTIVES

To assess genetic counselling by non-geneticists and to improve clinical practice.

DESIGN

National retrospective review of casenotes.

SETTING

Antenatal, paediatric, medical, and surgical units.

SAMPLE

1293 genetic events were identified, involving potentially avoidable cases of Down's syndrome, neural tube defect, cystic fibrosis, beta thalassaemia major and late onset medullary carcinoma of the thyroid (multiple endocrine neoplasia). Notes were available for review in 888 (69%) of these cases.

OUTCOMES

Documented counselling, offers of relevant genetic screening and prenatal diagnosis.

RESULTS

Clinical audit was frustrated by poor quality hospital records lacking evidence of counselling. Non-geneticist clinicians concentrate on the management of disease, and may overlook the need for counselling and recording data which patients will later need for decisions about reproduction or disease prevention. Counselling, screening and prenatal diagnosis were sometimes impossible because of late booking in pregnancy, or because of delayed diagnosis of an earlier affected child with cystic fibrosis. There are marked regional inequalities of access to genetic services, particularly for minority ethnic groups with increased risks of thalassaemia. Although patients were selected for this enquiry because they had known high risks of genetic disorders, on average less than half were referred to medical geneticists. General recommendations relevant for improvement of care for patients and families with medical genetic needs and those specific for each disorder are given.

CONCLUSIONS

Assessment of the quality of genetic care becomes increasingly important as genetic counselling spreads beyond the narrow confines of specialist genetic services. Even though the events studied in this enquiry largely occurred between 1991 and 1995, there is little reason to believe that clinicians in general have become markedly better trained in medical genetics. The General Medical Council and Medical Royal Colleges should urgently consider the need for a national policy for improving undergraduate and postgraduate medical, nursing and midwifery education in genetics. Commissioners of clinical services should require that genetic management be at least as well-documented as surgical operations, drug records and informed consent, perhaps by using a nationally agreed pro-forma for prenatal diagnosis. Regular audit of counselling provided by non-geneticists is necessary to confirm that clinical improvements are occurring and standards are being met. The Confidential Enquiry provides data for a systematic approach to clinical governance of genetics in all specialities. This sets the scene for multi-speciality NHS genetic services capable of giving patients greater consistency both in access and in quality.

Common fears: a comparison of adolescents' self-generated and fear survey schedule generated fears

Investigations into normative fear in adolescence have indicated that the most common fears are consistently death-related and danger-related. Assessments have most commonly been made from self-reports on fear survey schedules. The aim of the present study, therefore, was to determine whether adolescents would provide responses comparable to those generated through the use of a fear survey schedule when asked to list their 3 greatest fears. A total of 439 adolescents aged 11 to 18 years (237 girls, 201 boys, 1 sex not reported) listed their greatest fears; then they completed the 78-item Fear Survey Schedule for Children-II (E. Gullone & N. J. King, 1992). Consistent with past research, the 10 most common fears generated via the fear schedule related to death and danger. However, on the whole, the self-generated fears deviated from the death and danger theme, also including fear of failure, fear of animals, and fear of the unknown. A tendency toward global responses in self-generated fears appeared to encompass the majority of specific death-related fears included in the fear schedule, thus allowing for other predominant fears to be listed among the 3 most common.

Synthesis and immunosuppressant activity of pyrazole carboxamides

A series of novel pyrazole carboxamides is disclosed that demonstrate strong immunosuppressant activity in rodent and human mixed leukocyte response (MLR) assays (IC50 < 1 microM). The synthesis, biological activity, mode of action, and pharmacokinetic properties of this new lead series are discussed.