MR imaging contrast enhancement based on intermolecular zero quantum coherences

A new method for magnetic resonance imaging (MRI) based on the detection of relatively strong signal from intermolecular zero-quantum coherences (iZQCs) is reported. Such a signal would not be observable in the conventional framework of magnetic resonance; it originates in long-range dipolar couplings (10 micrometers to 1 millimeter) that are traditionally ignored. Unlike conventional MRI, where image contrast is based on variations in spin density and relaxation times (often with injected contrast agents), contrast with iZQC images comes from variations in the susceptibility over a distance dictated by gradient strength. Phantom and in vivo (rat brain) data confirm that iZQC images give contrast enhancement. This contrast might be useful in the detection of small tumors, in that susceptibility correlates with oxygen concentration and in functional MRI.     

Are European standard deviation targets for haemoglobin A1c too strict?

The Diabetes Control and Complications Trial (DCCT) has provided objective evidence for desirable glycaemic control in Type 1 patients and defines the benefits of good glycaemic control in terms of haemoglobin A1c (HbA1c) values. However, HbA1c assays vary, leading to suggestions that glycaemic control be classified according to numbers of standard deviations (SD) from a local non-diabetic population mean. We have classified the glycaemic control of 339 UK Type 1 diabetic patients (182 male, 157 female, median age 36 (range 15-74) years) using the DCCT to set HbA1c targets and compared this with the SD method. Using age matched controls (mean HbA1c 4.02%, SD 0.28%, n=106), SD guidelines classified 1% of patients into good (HbA1c <3SD from reference mean), 4% into borderline (3-5SD) and 95% into poor (>5SD) glycaemic control. When calibrating the same instrument to the DCCT analyser (r=0.996), 37% of patients had HbA1c results lower than the 7% median value found in the intensively treated DCCT group, while only 12% of patients had values greater than the 9% conventionally treated median HbA1c. DCCT subjects with HbA1c values of less than 8% belonged predominantly to the intensively treated group. In this study, 71% of patients fell into this category. Thus, guidelines based on numbers of SD away from a non-diabetic mean may overestimate the glycaemic control required to reduce microvascular complications in Type 1 patients. Standardizing to DCCT targets is more appropriate.     

Molecular characterization of seven Chinese isolates of infectious bursal disease virus: classical, very virulent, and variant strains

We have previously reported that certain tyrphostins which block EGF-R phosphorylation in cell-free systems fail to do so in intact cells. Nevertheless, we found that this family of tyrphostins inhibits both EGF- and calf serum-induced cell growth and DNA synthesis [Osherov, N.A., Gazit, C., Gilon, and Levitzki, A. (1993). Selective inhibition of the EGF and HER2/Neu receptors by Tyrphostins. J. Biol. Chem. 268, 11134-11142.] Now we show that these tyrphostins exert their inhibitory activity even when added at a time when the cells have already passed their restriction point and receptor activation is no longer necessary. AG555 and AG556 arrest 85% of the cells at late G1, whereas AG490 and AG494 cause cells to arrest at late G1 and during S phase. No arrest occurs during G2 or M phase. Further analysis revealed that these tyrphostins act by inhibiting the activation of the enzyme Cdk2 without affecting its levels or its intrinsic kinase activity. Furthermore, they do not alter the association of Cdk2 to cyclin E or cyclin A or to the inhibitory proteins p21 and p27. These compounds also have no effect on the activating phosphorylation of Cdk2 by Cdk2 activating kinase (CAK) and no effect on the catalytic domain of cdc25 phosphatase. These compounds lead to the accumulation of phosphorylated Cdk2 on tyrosine 15 which is most probably the cause for its inhibition leading to cell cycle arrest at G1/S. A structure-activity relationship study defines a very precise pharmacophore, suggesting a unique molecular target not yet identified and which is most probably involved in the regulation of the tyrosine-phosphorylated state of Cdk2. These compounds represent a new class of cell proliferation blockers whose target is Cdk2 activation.     

Bypass of abnormal MDM2 inhibition of p53-dependent growth suppression

Fourier transform infrared (FT-IR) microspectroscopy and chemometric methods have been applied to the study of fresh and simulated post-mortem human arterial tissue. The results have shown that although physical differences were observed using light microscopy, no spectroscopic distinction could be made between these groups. The presence of collagen throughout the artery wall results in characteristic absorptions which may mask any biochemical changes that could otherwise have been detected by the FT-IR technique. Because the structure of the artery is unique, these findings should be regarded as tissue specific.     

Atypical monoclonal plasma cell hyperplasia: its identity and treatment. Case report

Atypical monoclonal plasma cell hyperplasia, like plasma cell granuloma, is an inflammatory pseudotumor. Both are extremely rare in the central nervous system. Atypical monoclonal plasma cell hyperplasia is a recently identified neuropathological entity described by Weidenheim, et al., in 1989. A second case of this disease entity is now reported. The histological findings that differentiate this lesion from plasma cell granuloma, plasmacytoma, and meningioma are discussed. The present case clearly demonstrates the complete resolution of the disease after a course of fractionated radiotherapy.     

The role of complex, simultaneous trunk motions in the risk of occupation-related low back disorders

STUDY DESIGN: Simultaneous trunk kinematic variables of industrial workers performing jobs with varying degrees of low back disorder risk were quantified, by using a three-dimensional electrogoniometer. OBJECTIVES: To assess the distinguishing patterns of simultaneous multidimensional (complex) motion parameters of workers performing manual material handling jobs with varying degrees of low back disorder risk. SUMMARY OF BACKGROUND DATA: There is significant epidemiologic and biomechanical evidence that implicates simultaneously occurring or combined motions and loading as important risk factors follow back disorder. However, the specific levels or magnitudes and patterns of these complex motions at which risk of low back disorder is increased are still unknown. METHODS: An industrial database of 126 workers and jobs was used to quantify the complex trunk motions of groups with varying degrees of low back disorder risk. Three groups, low-, medium-, and high-risk, were defined on the basis of retrospective injury records of the corresponding jobs. The jobs were further classified into five cells of weight-lift rate combinations. Within each weight-lift rate cell, the three-dimensional trunk motion patterns of workers were analyzed. Bivariate distributions and cumulative distribution functions were used to compare the simultaneous occurrence of complex dynamic motions among risk groups. RESULTS: High- and medium-risk groups exhibited complex trunk motion patterns involving high magnitudes of combined velocities, especially at extreme sagittal flexion; whereas the low-risk group did not. Postural trunk information alone did not provide a consistent pattern of distinguishing among risk groups. CONCLUSIONS: Elevated levels of complex simultaneous velocity patterns were unique to groups with increased low back disorder risk. Knowledge of these complex trunk velocity patterns in combination with key workplace factors provides a more sensitive means for identifying low back disorder occupational risk factors than does mere postural information.     

Is there a rationale for the drugs used in hair transplantation surgery?

BACKGROUND: Various medications may be used before, during, or after hair transplantation surgery (HTS) with the aims of maximizing patient comfort, reducing unwanted side effects, and improving the results of HTS. OBJECTIVE: The objectives of this study were to determine the current practice pattern and rationale for drug prescribing by a group of leading hair transplant surgeons and to review the literature for the evidence upon which these prescribing patterns were based. METHODS: A postal questionnaire was sent to 16 hair transplant surgeons from the United States and Canada, and the answers were analyzed. The relevant evidence-based literature concerning HTS was reviewed by medicine search. RESULTS: Questionnaires suitable for analysis were received from 14 of the surgeons. There were many differences in the pattern of prescribing drugs for the HTS procedure. There was general agreement about the use of local anesthetics but no consensus about the withholding of agents that might increase bleeding; the use of pre- and postoperative analgesics; the use of topical and systemic antibiotics; the use of corticosteroids; or minoxidil. Randomized controlled studies relating to these issues for HTS were not identified in the literature. CONCLUSION: A lack of consensus exists about the drugs used in HTS based on a lack of evidence-based medicine.