Crushed stents in benign left brachiocephalic vein stenoses

Two hemodialysis patients presenting with left venous arm congestion due to benign catheter-induced stenosis of the left brachiocephalic vein were treated by angioplasty and stent placement. External compression of the stents was responsible for rapid recurrence of the symptoms. No osseous or vascular malformation could be identified. Mechanical constraints induced by respiratory chest wall motion and aortic arch flow-related pulsation are proposed to explain this observation. This potential hazard should be considered when stent placement into the left brachiocephalic vein is advocated.

Influence of intercellular junctions on endothelin secretion of human umbilical vein endothelial cells in vitro

The endothelium plays a pivotal role in the rheological regulation of blood flow by the secretion of vasoactive factors. The interaction between shear forces and the endothelium is determined by the mechanical properties of the endothelial cell layer which are associated with intercellular junctions. Cell-cell contacts could therefore modulate the secretion of vasocative factors in response to rheological stimuli. We investigated the relationship between intercellular junctions and the secretion of the vasoconstrictor peptide endothelin and the coagulation co-factor von Willebrand factor (vWF). Human umbilical vein endothelial cells (HUVECs) were used as in vitro endothelial model system. Intercellular junctions were reversibly disrupted by calcium chelation or hypertonic stress; alternatively, the formation of intercellular junctions was inhibited by culturing the cells in suspension or by plating them in the presence of an inhibitory anti-VE-cadherin antibody. The opening of intercellular junctions was verified by assessing transmonolayer electrical resistance (TMR) and immunofluorescence morphology. The concentration of endothelin and vWF was measured in the cell culture supernatants using specific ELISAs. The secretion of endothelin was inhibited by EGTA (5 mM) and stimulated by incubation with tumor necrosis factor alpha (TNFalpha, 40 ng/ml). Treatment with hypertonic medium (glycerol, 1,200 mosmol/l) for 10 minutes opened intercellular junctions and markedly reduced the secretion of endothelin. HUVECs in suspension culture did not secrete endothelin and failed to respond to TNFalpha, but readily resumed these functions upon forming a new monolayer on plastic. The reconstitution of intercellular junctions after suspension culture could be inhibited using a specific anti-VE-cadherin antibody. This antibody, but not a non-specific anti-human-IgG antibody reduced endothelin secretion. The secretion of von Willebrand Factor was less dependent on intercellular junctions. The opening of intercellular junctions did not induce cell death, since the cells continued to exclude trypan blue. The results of this study suggest a novel and potentially pathophysiologically/clinically relevant correlation between intercellular junctions and the secretion of endothelin in endothelial cells.

[Short-term memory performance of German and Chinese probands with verbal and figural items: on the function of the phonological loop and visual-spatial sketchpad]

In a computer-controlled experiment using n = 48 German and n = 48 Chinese subjects we established the memory span for simple geometrical figures and their names in the subjects' respective native language. Half of the subjects replied verbally, the other half nonverbally via a touch screen. In addition, verbal reproduction times were measured. Significant differences in memory span between the two language groups were found only under nonverbal report conditions: here, the Chinese subjects achieved better results than their German contemporaries. There were no differences in oral reproduction times between the two groups. The results are discussed within the framework of Baddeley's working memory model.

Temporal and topographical characterization of language cortices using intraoperative optical intrinsic signals

We used intraoperative optical imaging of intrinsic signals (iOIS) and electrocortical stimulation mapping (ESM) to compare functionally active brain regions in 10 awake patients undergoing neurosurgical resection. Patients performed two to four tasks, including visual and auditory naming, word discrimination, and/or orofacial movements. All iOIS maps included areas identified by ESM mapping. However, iOIS also revealed topographical specificity dependent on language task. In Broca's area, naming paradigms activated both anterior and posterior inferior frontal gyrus (IFG), while the word discrimination paradigm activated only posterior IFG. In Wernicke's area, object naming produced activations localizing over the inferior and anterior/posterior regions, while the word discrimination task activated superior and anterior cortices. These results may suggest more posterior phonological activation and more anterior semantic activations in Broca's area, and more anterior/superior phonological activation and more posterior/inferior semantic activations in Wernicke's area. Although similar response onset was observed in Broca's and Wernicke's areas, temporal differences were revealed during block paradigm (20-s) activations. In Broca's area, block paradigms yielded a boxcar temporal activation profile (in all tasks) that resembled response profiles observed in motor cortex (with orofacial movements). In contrast, activations in Wernicke's area responded with a more dynamic profile (including early and late peaks) which varied with paradigm performance. Wernicke's area profiles were very similar to response profiles observed in sensory and visual cortex. The differing temporal patterns may therefore reflect unique processing performed by receptive (Wernicke's) and productive (Broca's) language centers. This study is consistent with task-specific semantic and phonologic regions within Broca's and Wernicke's areas and also is the first report of response profile differences dependent on cortical region and language task.

[Enhanced imaging diagnosis of liver carcinomas. Technical progress is not a substitute for clinical knowledge]

Cholangiocellular carcinomas (CCCs) of the peripheral type (not Klatskin tumors) appear sonographically as solid space-occupying lesions. No typical sonomorphological signs are known. Important hint for the clinician is the knowledge of earlier or accompanying diseases in which CCCs occur more often (primary sclerosing cholangitis, ulcerative colitis, intrahepatic gallstones, parasitic diseases of the bile ducts, choledochal cysts, Caroli's syndrome). Typical Color-Doppler signs are also missing. Definitive diagnostic is left to biopsy. Hepatocellular carcinomas (HCCs) mostly occur in cirrhotic livers. Every newly detected space-occupying lesion in a cirrhotic liver is suspected of HCC until otherwise proven, even when AFP-levels are normal. AFP levels constantly higher than 400 ng/ml make HCC probable, AFP levels of 2000 ng/ml ore more proof HCC. Gray-scale imaging is not uniform and not guiding. Using Color-Doppler nearly all HCCs show markedly hyperperfusion compared to the surrounding liver tissue, vessels are arranged in a chaotic shape. Echo-enhanced Color-Doppler always shows a distinct early arterial hyperperfusion.

The association of diabetes specialist care with health care practices and glycemic control in patients with type 1 diabetes: a cross-sectional analysis from the Pittsburgh epidemiology of diabetes complications study

OBJECTIVE

To determine whether diabetes care characteristics and glycemic control differ by use of specialist care in a representative cohort of patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Health care, sociodemographic characteristics, and glycemic control were compared between participants in the Pittsburgh Epidemiology of Diabetes Complications Study who reported receiving specialist care (n = 212) and those who did not (n = 217). Specialist care was defined as having received care from an endocrinologist or diabetologist or diabetes clinic attendance during the last year.

RESULTS

Patients who reported receiving specialist care were more likely to be female, to have an education level beyond high school, to have an annual household income >$20,000, and to have health insurance. Additionally, patients receiving specialist care were more likely to have received diabetes education during the previous 3 years, to have knowledge of HbAlc testing and to have received that test during the previous 6 months, to have knowledge of the Diabetes Control and Complications Trial results, to self-monitor blood glucose, and to inject insulin more than twice daily. A lower HbA1 level was associated with specialist care versus generalist care (9.7 vs. 10.3%; P = 0.0006) as were higher education and income levels. Multivariate analyses suggest that the lower HbA1 levels observed in patients receiving specialist care were restricted to patients with an annual income >$20,000.

CONCLUSIONS

Specialist care was associated with higher levels of participation in diabetes self-care practices and a lower HbA1 level. Future efforts should research and address the failure of patients with low incomes to benefit from specialist care.

Can clinical factors estimate insulin resistance in type 1 diabetes?

An insulin resistance syndrome (IRS) score was developed based on clinical risk factors in adults with childhood-onset type 1 diabetes in the Epidemiology of Diabetes Complications (EDC) Study and was validated using euglycemic-hyperinsulinemic clamp studies. Hypertension, waist-to-hip ratio (WHR), triglyceride and HDL cholesterol levels, family history of type 2 diabetes, and glycemic control were risk factors used to define the score. A score of 1 (lowest likelihood IRS) to 3 (highest likelihood IRS) was assigned for each risk factor. Eligible subjects (n = 24) were recruited from the EDC cohort based on tertile of IRS score. Subjects received an overnight insulin infusion to normalize glucose levels, then underwent a 3-h euglycemic-hyperinsulinemic (60 mU x m(-2) x min(-1)) clamp. Glucose disposal rate (GDR) was determined during the last 30 min of the clamp. The GDR differed significantly by IRS group (9.65 +/- 2.99, 8.02 +/- 1.39, and 5.68 +/- 2.16 mg x kg(-1) x min(-1), P < 0.01). The GDR was inversely correlated with the IRS score (r = -0.64, P < 0.01). Using linear regression, the combination of risk factors that yielded the highest adjusted r2 value (0.57, P < 0.001) were WHR, hypertension, and HbA1. This study found that clinical risk factors can be used to identify subjects with type 1 diabetes who are insulin resistant, and it provides validation of a score based on clinical factors to determine the extent of insulin resistance in type 1 diabetes. This score will be applied to the entire EDC population in future studies to determine the effect of insulin resistance on complications.

Hydrolyses of alpha- and beta-cellobiosyl fluorides by Cel6A (cellobiohydrolase II) of Trichoderma reesei and Humicola insolens

We have measured the hydrolyses of alpha- and beta-cellobiosyl fluorides by the Cel6A [cellobiohydrolase II (CBHII)] enzymes of Humicola insolens and Trichoderma reesei, which have essentially identical crystal structures [Varrot, Hastrup, Schülein and Davies (1999) Biochem. J. 337, 297-304]. The beta-fluoride is hydrolysed according to Michaelis-Menten kinetics by both enzymes. When the approximately 2.0% of beta-fluoride which is an inevitable contaminant in all preparations of the alpha-fluoride is hydrolysed by Cel7A (CBHI) of T. reesei before initial-rate measurements are made, both Cel6A enzymes show a sigmoidal dependence of rate on substrate concentration, as well as activation by cellobiose. These kinetics are consistent with the classic Hehre resynthesis-hydrolysis mechanism for glycosidase-catalysed hydrolysis of the 'wrong' glycosyl fluoride for both enzymes. The Michaelis-Menten kinetics of alpha-cellobiosyl fluoride hydrolysis by the T. reesei enzyme, and its inhibition by cellobiose, previously reported [Konstantinidis, Marsden and Sinnott (1993) Biochem. J. 291, 883-888] are withdrawn. (1)H NMR monitoring of the hydrolysis of alpha-cellobiosyl fluoride by both enzymes reveals that in neither case is alpha-cellobiosyl fluoride released into solution in detectable quantities, but instead it appears to be hydrolysed in the enzyme active site as soon as it is formed.

Clinical evaluation of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors

PURPOSE

We investigated the value of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors.

METHODS

We prospectively examined 105 focal liver lesions in 100 patients by real-time gray-scale sonography, color Doppler sonography, and contrast-enhanced color Doppler sonography with galactose-based microbubbles (SH U 508A; Levovist). The final diagnoses of the liver lesions as confirmed by pathology or additional imaging techniques were 31 metastases, 25 hemangiomas, 19 hepatocellular carcinomas, 19 focal nodular hyperplasias, 2 cholangiocellular carcinomas, and 9 other lesions.

RESULTS

Vascularity could be detected in 43 (41%) of the 105 lesions by conventional color Doppler sonography compared to 67 (64%) by contrast-enhanced color Doppler sonography. Contrast-enhanced color Doppler sonography identified moderate or extensive vascularity in all 19 focal nodular hyperplasias, moderate or extensive vascularity in 16 hepatocellular carcinomas and both cholangiocellular carcinomas, and no or minor vascularity in all but 3 hemangioma. The combination of gray-scale, conventional color Doppler, and contrast-enhanced color Doppler sonography led to the correct diagnosis in 81% of cases (85 of 105), compared to 57% (60/105) for gray-scale and conventional color Doppler sonography and 31% (33/105) for gray-scale sonography alone.

CONCLUSIONS

Contrast-enhanced color Doppler sonography improves the detection of tumor vascularity and is useful in the differential diagnosis of liver lesions.

Macroscopic spectral imaging and gene expression analysis of the early stages of melanoma

BACKGROUND

The stages of melanocytic progression are defined as atypical (dysplastic) nevus, melanoma in situ, melanoma in the radial growth phase (RGP), melanoma in the vertical growth phase (VGP), and melanoma in the metastatic growth phase (MGP). Melanoma in situ and RGP melanoma often develop in contiguous association with atypical nevi. This frequently poses a problem with respect to their early detection. Furthermore, unlike cells obtained from VGP and MGP melanomas, cells derived from melanoma in situ and RGP melanoma do not proliferate in vitro. Thus, compared to the late stages of the disease, less information is available regarding genes expressed in the early stages.

MATERIALS AND METHODS

To determine whether spectral imaging, a recently developed optical imaging technique, can detect melanoma in situ and RGP melanoma arising in melanoma precursor lesions, atypical nevi in patients with a clinical history of melanoma were subjected to noninvasive macroscopic spectral imaging. To determine at what stage in the progression pathway of melanoma genes having important biological functions in VGP and MGP melanomas are activated and expressed, lesions of melanoma in situ were analyzed by immunohistochemistry and in situ hybridization for expression of some of these known molecular and immunologic markers.

RESULTS

The present study demonstrates the capability of noninvasive spectral imaging to detect melanoma in situ and RGP melanoma that arise in contiguous association with atypical nevi. Furthermore, the study provides evidence that genes and antigens expressed in VGP and MGP melanoma are also expressed in melanoma in situ.

CONCLUSIONS

Because of the dark and variegated pigmentation of atypical nevi, melanoma in situ and RGP melanoma that arise in these melanoma precursor lesions are often difficult to recognize and thus frequently go unnoticed. The application of new optical screening techniques for early detection of melanoma and the identification of genes expressed in the early stages of melanoma development are two important avenues in the pursuit of melanoma prevention. The investigations presented here document that macroscopic spectral imaging has the potential to detect melanoma in its early stage of development and that genes essential for the proliferation and cell adhesion of VGP and MGP melanoma are already expressed in melanoma in situ.

A missense mutation in myosin VIIA prevents aminoglycoside accumulation in early postnatal cochlear hair cells

Myosin VIIA is expressed by sensory hair cells in the inner ear and proximal tubule cells in the kidney, the two primary targets of aminoglycoside antibiotics. Using cochlear cultures prepared from early postnatal Myo7a6J mice with a missense mutation in the head region of the myosin VIIA molecule we show that this myosin is required for aminoglycoside accumulation in cochlear hair cells. Hair cells in homozygous mutant Myo7a6J cochlear cultures have disorganized hair bundles, but are otherwise morphologically normal and transduce. However, and in contrast to hair cells from heterozygous Myo7a6J cultures, the homozygous Myo7a6J hair cells do not accumulate [3H]gentamicin and do not exhibit an ototoxic response on exposure to aminoglycoside. Possible roles for myosin VIIA in the process of aminoglycoside accumulation are discussed.

Allergen-specific immune deviation from a TH2 to a TH1 response induced by dendritic cells and collagen type I

BACKGROUND

Atopy and IgE production are associated with enhanced allergen-specific T(H)2 responses. Therefore a causative treatment may result from the deviation of this T(H)2-dominated immune response toward a T(H)1 response.

OBJECTIVE

This study was carried out to analyze whether dendritic cells, the most potent antigen-presenting cells that are also known to induce antigen-specific T(H)1 responses, are suitable for therapy of atopic diseases by shifting the allergen-specific T(H)2 response toward a T(H)1 response.

METHODS

Monocyte-derived dendritic cells were used to present allergens in vitro to autologous CD4(+) T cells of allergic persons. Because collagen type I activates dendritic cells and enhances the secretion of IL-12, we performed allergen presentation assays also in the presence of collagen type I.

RESULTS

After stimulation with allergen-pulsed dendritic cells the production of IFN-gamma as well as that of IL-4 and IL-5 by CD4(+) T cells was enhanced. In the presence of collagen type I, however, a significant shift toward a T(H)1 response with increased production of IFN-gamma and a decreased production of IL-5 could be observed. When T cells were stimulated directly with anti-CD3 and anti-CD28 in the absence of antigen-presenting cells, it was demonstrated that collagen type I also exerted a direct effect on T cells, increasing their IFN-gamma production.

CONCLUSION

These data indicate that collagen type I influences dendritic cells as well as T cells in a way that a shift in cytokine production results in a T(H)1 response even in already-sensitized atopic individuals.

Auxin-induced K+ channel expression represents an essential step in coleoptile growth and gravitropism

Auxin-induced growth of coleoptiles depends on the presence of potassium and is suppressed by K+ channel blockers. To evaluate the role of K+ channels in auxin-mediated growth, we isolated and functionally expressed ZMK1 and ZMK2 (Zea mays K+ channel 1 and 2), two potassium channels from maize coleoptiles. In growth experiments, the time course of auxin-induced expression of ZMK1 coincided with the kinetics of coleoptile elongation. Upon gravistimulation of maize seedlings, ZMK1 expression followed the gravitropic-induced auxin redistribution. K+ channel expression increased even before a bending of the coleoptile was observed. The transcript level of ZMK2, expressed in vascular tissue, was not affected by auxin. In patch-clamp studies on coleoptile protoplasts, auxin increased K+ channel density while leaving channel properties unaffected. Thus, we conclude that coleoptile growth depends on the transcriptional up-regulation of ZMK1, an inwardly rectifying K+ channel expressed in the nonvascular tissue of this organ.

Reproducibility of irritant patch test reactions to sodium lauryl sulfate in a double-blind placebo-controlled randomized study using clinical scoring. Results from a study group of the German Contact Dermatitis Research Group (Deutsche Kontaktallergie-Gruppe, DKG)

Reading of doubtful patch test reactions can be improved by comparing them to defined negative, allergic and irritant controls. For the latter, an irritant patch test is needed that gives sufficiently reproducible results. In our double-blind, placebo-controlled, randomized study, we have analysed the synchronous reproducibility of patch tests with 0%, 0.0625%, 0.125%, 0.25%, 0.5% and 1.0% sodium lauryl sulfate (SLS). Tests and readings were done according to ESCD guidelines. 139 patients (75 women, 64 men) 18 to 77 years old were tested. The % of positive patients as well as the % of reproducible positive reactions increased with rising concentrations of SLS to a maximum of approximately 90% and 85%, respectively, with 1% SLS. Time courses of reactions were also related to the concentration of SLS: with 1% SLS, plateau-type time courses were most common (65%), followed by decrescendo- (23%) and crescendo-type reactions (12%). With 1% SLS, very similar mild to moderate reactions were obtained on days 2 and 3. The reaction threshold and reproducibility of tests were not related to age and sex of patients or to their own assessment of skin irritability. We conclude that 1% SLS is appropriate for an irritant patch test that gives sufficiently reproducible results.

Evolution of the HOXB6 intergenic region: motif conservation at the lateral plate mesoderm (LPM) enhancer element

This study reports the results of a comparative sequencing study in higher primates, focusing on the intergenic region located between HOXB6 and HOXB7. We have examined an 832 bp. region, encompassing a putative Lateral Plate Mesoderm (LPM) enhancer element in a variety of anthropoid apes. The interspecific comparisons reveal extensive substitutions occurring within this region, with a marked bias in favor of C-->T transitions within the enhancer element. The pattern of these substitutions suggests that the LPM enhancer region is subject to specific sequence and compositional constraints that are only revealed through comparative sequencing. These constraints produce an enhancer signature, the CpG microisland, which may be useful in identifying additional regulatory elements located within the HOX complexes. J. Exp. Zool. (Mol. Dev. Evol.) 285:170-176, 1999.

Percutaneous ethanol injection and radio-frequency ablation for the treatment of nonresectable colorectal liver metastases - techniques and results

BACKGROUND

Percutaneous ethanol injection (PEI) and radio-frequency (RF) ablation are possible palliative treatment modalities for patients with non-resectable liver metastases of colorectal carcinomas. The different techniques are explained and reviewed.

RESULTS

PEI did not show promising results for the treatment of liver metastases. RF results were more encouraging; some studies showed improved mean survival times for patients when a complete necrosis of the metastases could be achieved. The maximum diameter of the necrotic area possible in a single session is about 5 cm.

CONCLUSION

PEI and RF are palliative last-line treatment strategies for patients with non-resectable liver metastases and should only be applied if chemotherapy is not sufficient or not possible. The long-term efficacy of RF ablation in this group of patients has to be evaluated.

Improved glycemic control reduces the impact of weight gain on cardiovascular risk factors in type 1 diabetes. The Epidemiology of Diabetes Complications Study

OBJECTIVE

To assess the prevalence and incidence of being overweight in type 1 diabetes, to identify factors associated with weight gain and improved glycemic control, and to examine relationships among weight gain, glycemic control, and cardiovascular risk factors.

RESEARCH DESIGN AND METHODS

The prevalence and incidence of being overweight in the Pittsburgh Epidemiology of Diabetes Complications (EDC) cohort (n = 441) were compared with the general population (National Health and Nutrition Examination Survey [NHANES]). Factors associated with weight gain and improved glycemic control were identified, and relationships among weight gain, glycemic control, and cardiovascular risk factors were examined over a 6.9 +/- 2.2-year period.

RESULTS

At baseline, the prevalence of being overweight (BMI > 27.8 kg/m2 for men and > 27.3 kg/m2 for women) was 10.4 and 11.4%, respectively, and was lower than the age- and sex-specific estimate for the general population (P < 0.05). The incidence of being overweight was comparable in men (12.6%) and women (11.8%) and did not differ from the general population (P = 0.98). Weight gain correlated with improvements in HbA1c (r = -0.21, P < 0.001). Patients with the highest baseline HbA1c levels gained the most weight and had the greatest improvement in glycemic control. A lower baseline BMI was also associated with a greater improvement in glycemic control. Weight gain favorably influenced the lipid profile in the setting of improved glycemic control, but adversely influenced the lipid profile in the absence of improved glycemic control. Weight change was directly associated with blood pressure change, but the incidence of hypertension was more strongly influenced by the development of nephropathy.

CONCLUSIONS

The prevalence of being overweight in type 1 diabetes remains lower than that in the general population. Moderate weight gain did not adversely affect the cardiovascular risk profile in the setting of improved glycemic control.