Ischaemic stroke with multi-focal venous and arterial thrombosis due to hyperhomocysteinemia: anabolic androgenic steroid use and MTHFR c.667 C > T variant - a case report.

BACKGROUND: Severely elevated serum homocysteine is a rare cause of ischaemic stroke and extra-cranial arterial and venous thrombosis. Several factors can lead to mild elevation of homocysteine including dietary folate and B12 deficiency, and genetic variants of the methylenetetrahydrofolate reductase (MTHFR) enzyme. The use of Anabolic androgenic steroid (AAS) is under-reported, but increasingly linked to ischaemic stroke and can raise homocysteine levels. CASE REPORT: We present a case of a man in his 40s with a large left middle cerebral artery (MCA) territory ischaemic stroke and combined multifocal, extracranial venous, and arterial thrombosis. His past medical history was significant for Crohn's disease and covert use of AAS. A young stroke screen was negative except for a severely elevated total homocysteine concentration, folate and B12 deficiencies. Further tests revealed he was homozygous for the methylenetetrahydrofolate reductase enzyme thermolabile variant (MTHFR c.667 C > T). The etiology of this stroke was a hypercoagulable state induced by raised plasma homocysteine. Raised homocysteine in this case was likely multifactorial and related to chronic AAS use in combination with the homozygous MTHFR c.677 C > T thermolabile variant, folate deficiency and, vitamin B12 deficiency. CONCLUSION: In summary, hyperhomocysteinemia is an important potential cause of ischaemic stroke and may result from genetic, dietary, and social factors. Anabolic androgenic steroid use is an important risk factor for clinicians to consider, particularly in cases of young stroke with elevated serum homocysteine. Testing for MFTHR variants in stroke patients with raised homocysteine may be useful to guide secondary stroke prevention through adequate vitamin supplementation. Further studies looking into primary and secondary stroke prevention in the high-risk MTHFR variant cohort are necessary.

Hybrid-integrated diode laser in the visible spectral range.

Generating visible light with wide tunability and high coherence based on photonic integrated circuits is of high interest for applications in biophotonics, precision metrology, and quantum technology. Here we present, to our knowledge, the first demonstration of a hybrid-integrated diode laser in the visible spectral range. Using an AlGaInP optical amplifier coupled to a low-loss Si3N4 feedback circuit based on microring resonators, we obtain a spectral coverage of 10.8 nm around 684.4 nm wavelength with up to 4.8 mW output power. The measured intrinsic linewidth is 2.3±0.2kHz.

Adhesion of Escherichia coli under flow conditions reveals potential novel effects of FimH mutations.

FimH-mediated adhesion of Escherichia coli to bladder epithelium is a prerequisite for urinary tract infections. FimH is also essential for blood-borne bacterial dissemination, but the mechanisms are poorly understood. The purpose of this study was to assess the influence of different FimH mutations on bacterial adhesion using a novel adhesion assay, which models the physiological flow conditions bacteria are exposed to. We introduced 12 different point mutations in the mannose binding pocket of FimH in an E. coli strain expressing type 1 fimbriae only (MSC95-FimH). We compared the bacterial adhesion of each mutant across several commonly used adhesion assays, including agglutination of yeast, adhesion to mono- and tri-mannosylated substrates, and static adhesion to bladder epithelial and endothelial cells. We performed a comparison of these assays to a novel method that we developed to study bacterial adhesion to mammalian cells under flow conditions. We showed that E. coli MSC95-FimH adheres more efficiently to microvascular endothelium than to bladder epithelium, and that only endothelium supports adhesion at physiological shear stress. The results confirmed that mannose binding pocket mutations abrogated adhesion. We demonstrated that FimH residues E50 and T53 are crucial for adhesion under flow conditions. The coating of endothelial cells on biochips and modelling of physiological flow conditions enabled us to identify FimH residues crucial for adhesion. These results provide novel insights into screening methods to determine the effect of FimH mutants and potentially FimH antagonists.

Udder firmness as a possible indicator for clinical mastitis.

Swelling of the mammary gland is an important sign to detect clinical mastitis (CM) in dairy cows. The overall objective of this study was to evaluate if udder firmness can be used as a cow-side indicator for mastitis and to evaluate how CM affects firmness within 14 d after diagnosis. A dynamometer was used to objectively determine udder firmness before and after milking in 45 cows with CM and 95 healthy cows. Udder firmness of both hind quarters was measured daily on 3 locations (upper, middle, lower measuring point) from the day of mastitis diagnosis until d 7 and again on d 14. Firmness of the middle measuring point was highest before and after milking in all cows. Udder firmness before milking was similar in quarters without and with CM. Subsequently, we concentrated on firmness measured on the middle point after milking. After milking, quarters with CM were firmer than healthy quarters. An increase of firmness of a quarter with mastitis did not affect firmness of the healthy neighboring quarter, nor did firmness of all healthy quarters differ. One firmness value per cow [i.e., Δ firmness (difference in udder firmness between both hind quarters)] was used for all further calculations. After fitting a generalized mixed model, CM affected Δ firmness in all cases. In multiparous cows, Δ firmness was also affected by continuous milk yield per day and DIM. Firmness thresholds for detection of CM were calculated using receiver operation characteristic curves. The threshold for detection of CM using Δ firmness was 0.282 kg (area under the curve: 0.722, sensitivity: 64.3%, specificity: 89.7%) and 0.425 kg (area under the curve: 0.817, sensitivity: 62.5%, specificity: 96.7%) in primiparous cows and multiparous cows, respectively. Linear mixed-model ANOVA were used to evaluate how CM affects udder firmness within 14 d after diagnosis. Cows with CM had a higher Δ firmness compared with cows without CM throughout the 14 d after the mastitis diagnoses. Parity had an effect on Δ firmness. Depending on systemic signs of sickness, mastitic cows were divided into cows having mild to moderate (n = 21) or severe mastitis (n = 24). Cows with severe mastitis suffered from a firmer udder on all measuring days. Bacteriological cure was defined based on 2 milk samples taken at 7 and 14 d after enrollment. An effect of parity and bacteriological cure on Δ firmness of cows with CM did not exist within the 14 d. Cows not clinically cured showed an increased Δ firmness of 0.560 kg compared with cured cows. In conclusion, udder firmness can be a useful indicator for CM. Further research is warranted to evaluate if udder firmness can be used as a predictor for the prognosis of a CM or the cure of inflammation.

Effect of Heat Stress on Concentrations of Faecal Cortisol Metabolites in Dairy Cows.

The negative impact of heat stress on health and productivity of dairy cows is well known. Heat stress can be quantified with the temperature-humidity index (THI) and is defined as a THI ≥ 72. Additionally, animal welfare is affected in cows living under heat stress conditions. Finding a way to quantify heat stress in dairy cows has been of increasing interest over the past decades. Therefore, the objective of this study was to evaluate concentrations of faecal glucocorticoid metabolites [i.e. 11,17-dioxoandrostanes (11,17-DOA)] as an indirect stress parameter in dairy cows without heat stress (DOA 0), with heat stress on a single day (acute heat stress, DOA 1) or with more than a single day of heat stress (chronic heat stress, DOA 2). Cows were housed in five farms under moderate European climates. Two statistical approaches (approach 1 and approach 2) were assessed. Using approach 1, concentrations of faecal 11,17-DOA were compared among DOA 0, DOA 1 and DOA 2 samples regardless of their origin (i.e. cow, unpaired comparison with a one-way anova). Using approach 2, a cow was considered as its own control; that is 11,17-DOA was treated as a cow-specific factor and only paired samples were included in the analysis for this approach (paired comparison with t-tests). In approach 1 (p = 0.006) and approach 2 (p = 0.038), 11,17-DOA values of cows under acute heat stress were higher compared to those of cows without heat stress. Our results also indicate that acute heat stress has to be considered as a confounder in studies measuring faecal glucocorticoid metabolites in cows to evaluate other stressful situations.

Certifications for sight impairment due to age related macular degeneration in England.

OBJECTIVES: To examine variability across England in certification rates for age related macular degeneration (AMD) between 1st April 2011 and 31st March 2012. STUDY DESIGN: Cross-sectional survey. METHODS: An electronic version of the CVI, the ECVI, was used at the Certifications Office, London, to transfer information from paper based certificates into a database. The electronic certifications data set was queried for all certificates completed in England between April 1st 2011 and March 31st 2012 with the main cause of certifiable visual loss being AMD or with the main cause of certifiable visual loss being multiple pathology but a contributory cause being AMD. Data were explored by type of AMD, visual status, age and sex and then directly standardized rates were computed by English region. RESULTS: The Certifications Office received 23,616 CVIs for England between April 2011 and March 2012, of which 10,481 (44%) were people certified severely sight-impaired (blind) (SSI) and 12,689 (54%) were certified as sight-impaired (partial sight) (SI). The remainder did not have visual status classified. AMD contributed to 11546 causes of certification on the CVI forms during this period, 53% of forms being for geographic atrophy (GA)/dry AMD which is currently mostly untreatable. The median (interquartile) age at certification for AMD was 86 (81, 90) years and women were more commonly certified than men (66%). Considerable variability was seen across English regions, although there was consistency in that GA was the more common form in all areas. CONCLUSIONS: There is considerable regional variability in CVI rates in England, which are not attributable to differences in age or sex. Reasons for such variability need examination yet this should not undermine the value of these data in terms of describing those newly registered with sight impairment due to AMD who are predominantly female and over 85 years of age.

Evaluation of udder firmness by palpation and a dynamometer.

Swelling of the mammary gland is an important health status sign for clinical exploration and palpation is a routine diagnostic tool for mastitis detection in dairy cows. Data on repeatability or validity of specific methods of udder palpation are rare. The overall objective was to study the validity of estimates of udder firmness generated by palpation and by using a validated dynamometer. Specifically, we set out to determine within-observer repeatability and between-observer repeatability in 2 specific experiments. Additionally, we compared a 4-point palpation scoring system with estimates obtained with a dynamometer in this study. In a pilot trial, we determined the range of udder firmness of 25 cows and developed an in vitro model for udder firmness. This model enabled training of the observers and allowed investigating a 4-point palpation scoring system. In vivo, udder firmness was determined before and after milking by palpation and by using a dynamometer. Within-observer repeatability based on estimates of udder firmness of 25 cows obtained by 3 observers on a single day by palpation was 0.968. Within-observer repeatability of estimates of udder firmness of 25 cows obtained with the dynamometer by a single observer was 0.997. The coefficient of variation of the same measures was 9.1%. To determine between-observer repeatability (palpation: 0.932; dynamometer: 0.898), udder firmness of 100 cows was measured on 4 different days by 9 observers in experiment 2. Udder firmness in dairy cows could be measured repeatably with the dynamometer and by palpation, especially when performed by a single observer. Estimates of udder firmness generated by palpation and with the dynamometer were moderately related (correlation coefficient = 0.54). Training of observers through the pilot trial or practical experience in the 4 d of the study in experiment 2 did not improve the correlation. Further research is warranted to understand how udder firmness develops in infected udders.

Differences between men and women in the regulation of adipose 11ß-HSD1 and in its association with adiposity and insulin resistance.

This study explored sex differences in 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) activity and gene expression in isolated adipocytes and adipose tissue (AT), obtained via subcutaneous biopsies from non-diabetic subjects [58 M, 64 F; age 48.3 ± 15.3 years, body mass index (BMI) 27.2 ± 3.9 kg/m²]. Relationships with adiposity and insulin resistance (IR) were addressed. Males exhibited higher 11ß-HSD1 activity in adipocytes than females, but there was no such difference for AT. In both men and women, adipocyte 11ß-HSD1 activity correlated positively with BMI, waist circumference, % body fat, adipocyte size and with serum glucose, triglycerides and low-density lipoprotein:high-density lipoprotein (LDL:HDL) ratio. Positive correlations with insulin, HOMA-IR and haemoglobin A1c (HbA1c) and a negative correlation with HDL-cholesterol were significant only in males. Conversely, 11ß-HSD1 activity in AT correlated with several markers of IR and adiposity in females but not in males, but the opposite pattern was found with respect to 11ß-HSD1 mRNA expression. This study suggests that there are sex differences in 11ß-HSD1 regulation and in its associations with markers of obesity and IR.

Repeated measurements of 11ß-HSD-1 activity in subcutaneous adipose tissue from lean, abdominally obese, and type 2 diabetes subjects--no change following a mixed meal.

The aim of this study was to measure 11ß-HSD-1 activity in subcutaneous adipose tissue by an ex vivo method in three subgroups; lean, obese, and type 2 diabetes subjects, both in the fasting state and after a mixed meal and to determine the variability and reproducibility of this method. Eighteen subjects were investigated; 6 lean, 6 abdominally obese, and 6 type 2 diabetes subjects (BMI 22 ± 1, 30 ± 3 and 31 ± 3 kg/m², respectively). Needle biopsies were taken repeatedly and an index of 11ß-HSD-1 activity was measured as percent conversion of (3)H-cortisone to (3)H-cortisol/100 mg tissue. For two separate biopsies taken in the fasting state on the same day, the within subjects CV was 16% and the between CV was 36% for 11ß-HSD-1 activity for all subjects. For two biopsies taken in the fasting state at two different days, the total within subjects CV was 38% and the between subjects CV was 46%. Lean subjects had lower 11ß-HSD-1 activity (4.8 ± 1.5% conversion of ³H-cortisone to ³H-cortisol/100 mg tissue) than both obese (14.4 ± 1.6% conversion, p<0.01) and type 2 diabetes subjects (11.7 ± 1.9% conversion, p<0.05) in the fasting state. There was no effect of a meal on 11ß-HSD-1 activity in any of the three groups. The conclusions from this study are: 1) the variation coefficient for the ex vivo adipose tissue 11ß-HSD-1 activity method was ∼25% for repeat measures within subjects; 2) food intake had no major impact on enzyme activity; and 3) 11ß-HSD-1 activity in subcutaneous adipose tissue was significantly increased in obese subjects with or without T2DM compared to lean subjects without diabetes.

Appearance of functional insulin receptors during the differentiation of embryonal carcinoma cells.

The insulin-receptor binding activity and insulin-stimulated growth response of PC13 clone 5 cells were investigated for both the embryo carcinoma (EC) and retinoic acid-induced differentiated derivatives of this cell line. Whereas the EC cell was found to have very few, if any, receptors and showed no demonstrable dependence on insulin for growth, the differentiated derivative cell expressed a large number of insulin receptors and, when challenged with the hormone, showed stimulation of both DNA synthesis and cell division. The same data were obtained for five independent PC13 clones. These results, coupled with previous observations, lend weight to the suggestion that the appearance of specific receptors for growth regulatory substances may be a manifestation of a general change in growth-regulatory mechanisms accompanying EC cell differentiation and loss of malignancy.

The hunchback and its neighbours: proline as an environmental modulator.

The unique ability of Pro or Pro-rich repeats to affect the stability and function of proteins has recently been highlighted by biophysical studies on fragments from prions, signalling domains and muscle proteins. Pro-rich regions have been observed to either occupy disordered states or adopt various helical structures; some are also able to undergo an environmental-dependent transformation between these states. Such a transformation could explain some of the inherent functional properties of the parent proteins and, additionally, can be efficiently exploited to generate novel temperature- and pH-switches in more conventional globular proteins.

The distribution of nitric oxide synthase in the inferior colliculus of guinea pig.

The modulation of neuronal activity by the gas nitric oxide is one of the most novel discoveries in neuroscience. In the auditory pathway, the highest expression of nitric oxide synthase is found in the inferior colliculus (IC), an important center for the convergence of parallel ascending pathways traveling in the brainstem, and descending projections from the auditory cortex. Here we use immunocytochemistry with an antibody for neuronal nitric oxide synthase (nNOS), or NOS Type 1, to map the distribution of nNOS expression in the IC of the guinea pig. The results show that nNOS is differentially expressed by both cell bodies and neuropil across its different subdivisions. The highest levels of neuronal staining are seen in the dorsal and lateral cortices, and the commissural nucleus, making them readily distinguishable from the ventro-lateral part of the central nucleus where nNOS expression in neuropil and somata is minimal. Dorso-medially, and caudally, however, the region of nNOS expression extends from the dorsal cortex into the area normally designated as the central nucleus, and nNOS is expressed by neurons characteristic of this subdivision. Our findings support the idea of a gradual transition in cell properties rather than a distinct boundary between the central nucleus and the dorsal cortex. This transition zone may provide a cytoarchitectonic substrate for functional interaction between these two subdivisions.

The impact of surgeon and pathologist on lymph node retrieval in colorectal cancer and its impact on survival for patients with Dukes' stage B disease.

OBJECTIVE: An adequate lymph node harvest is necessary for accurate Dukes' stage discrimination in colorectal cancer. The aim of this study is to identify the effect of variables, including the individual surgeon and pathologist, on lymph node harvest in a single institution. METHOD: Three hundred and eighty one consecutive patients had resection for colorectal cancer, in a single unit. Factors influencing lymph node retrieval, including individual surgeon and reporting pathologist, were subjected to uni- and multivariate analysis. Actuarial survival of all patients with Dukes' stage B and C disease was then calculated and survival compared between Dukes' stage B and C at differing levels of lymph node harvest. RESULTS: The unit median lymph node harvest was 13 nodes/patient (95% CI 13.1-14.5). There was no difference in lymph node harvest between specialist colorectal surgeons and the pooled results of four nonspecialist consultant surgeons. However, there was a significant difference between reporting pathologists (P < 0.001). On univariate analysis, operation type, operative urgency, Dukes' stage, T-stage, reporting pathologist and use of neoadjuvant therapy in rectal cancer, were found to significantly affect lymph node retrieval. On multivariate analysis, operation type, T-stage, reporting pathologist and neoadjuvant therapy in rectal cancer remained significant variables. Patients with one or more lymph node metastasis had greater nodal harvests than those without (median 15 vs 12 P = 0.02). Survival of patients with Dukes' stage B disease was found to improve as lymph node harvest increased. CONCLUSION: Overall lymph node harvest, in this unit, varied according to the reporting pathologist but not operating surgeon. As lymph node harvest increased to 15 per patient, the probability of identifying a metastatic node increased.

Right parietal cortex is involved in the perception of sound movement in humans.

Changes in the delay (phase) and amplitude of sound at the ears are cues for the analysis of sound movement. The detection of these cues depends on the convergence of the inputs to each ear, a process that first occurs in the brainstem. The conscious perception of these cues is likely to involve higher centers. Using novel stimuli that produce different perceptions of movement in the presence of identical phase and amplitude modulation components, we have demonstrated human brain areas that are active specifically during the perception of sound movement. Both functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) demonstrated the involvement of the right parietal cortex in sound movement perception with these stimuli.

Aligning maps of visual and auditory space. Sensory maps.

Visual and auditory space are represented topographically in the superior colliculus in the midbrain. Recent experiments show that N-methyl-D-aspartate (NMDA) receptors play an important role in aligning auditory and visual maps during development.

Sensitivity to dynamic auditory and visual stimuli predicts nonword reading ability in both dyslexic and normal readers.

BACKGROUND: Developmental dyslexia is a specific disorder of reading and spelling that affects 3-9% of school-age children and adults. Contrary to the view that it results solely from deficits in processes specific to linguistic analysis, current research has shown that deficits in more basic auditory or visual skills may contribute to the reading difficulties of dyslexic individuals. These might also have a crucial role in the development of normal reading skills. Evidence for visual deficits in dyslexia is usually found only with dynamic and not static stimuli, implicating the magnocellular pathway or dorsal visual stream as the cellular locus responsible. Studies of such a dissociation between the processing of dynamic and static auditory stimuli have not been reported previously. RESULTS: We show that dyslexic individuals are less sensitive both to particular rates of auditory frequency modulation (2 Hz and 40 Hz but not 240 Hz) and to dynamic visual-motion stimuli. There were high correlations, for both dyslexic and normal readers, between their sensitivity to the dynamic auditory and visual stimuli. Nonword reading, a measure of phonological awareness believed crucial to reading development, was also found to be related to these sensory measures. CONCLUSIONS: These results further implicate neuronal mechanisms that are specialised for detecting stimulus timing and change as being dysfunctional in many dyslexic individuals. The dissociation observed in the performance of dyslexic individuals on different auditory tasks suggests a sub-modality division similar to that already described in the visual system. These dynamic tests may provide a non-linguistic means of identifying children at risk of reading failure.

Molecular cloning of the human Goodpasture antigen demonstrates it to be the alpha 3 chain of type IV collagen.

To characterize the autoantigen of Goodpasture's (anti-glomerular basement membrane) disease, a molecule of 26-kD reactive with autoantibodies from patients' sera was purified from collagenase digests of sheep glomerular basement membrane. Short internal amino acid sequences were obtained after tryptic or cyanogen bromide cleavage, and used to deduce redundant oligonucleotides for use in the polymerase chain reaction on cDNA derived from sheep renal cortex. Molecules of 175 bp were amplified and found to come from two cDNA sequences. One was identical to that of a type IV collagen chain (alpha 5) cloned from human placenta and shown to be expressed in human kidney. The other was from a type IV collagen chain with close similarities to alpha 1 and alpha 5 chains, and was used to obtain human cDNA sequences by cDNA library screening and by further polymerase chain reaction amplifications. The correspondence of the derived amino acid sequence of the new chain with published protein and cDNA sequences shows it to be the alpha 3 chain of type IV collagen. Its gene, COL4A3, maps to 2q36-2q37. The primary sequence and other characteristics of this chain confirm that it carries the Goodpasture antigen.