Optimized detection of changes in glucose-6-phosphate levels in human skeletal muscle by 31P MR spectroscopy.

As glucose-6-phosphate (G6P) plays a central role in muscle energy metabolism, the possibility to observe changes in the tissue level of this compound in vivo is very relevant. G6P can be detected noninvasively by (31)P MR spectroscopy, but its visibility in vivo is severely hampered due to low tissue levels and spectral overlap with other, stronger phosphomonoester signals. To optimize the observation of changes in G6P levels in human calf muscle by (31)P MR spectroscopy at 1.5 T, we implemented an approach involving a new RF probe and a postacquisition correction method. An anatomically shaped circularly polarized (31)P coil was designed for high intrinsic sensitivity. Together with an additional (1)H coil and (1)H blocking circuits this allowed the application of NOE and (1)H decoupling to further enhance sensitivity. A hyperglycemic hyperinsulinemic clamp was used to increase G6P levels. The spectra were corrected for frequency and phase drift due to scanner instability and leg movements using an automated phase and frequency correction method. Difference (31)P spectroscopy was applied to detect changes of the G6P signal. The result, in five healthy subjects, demonstrated that the combination of sensitivity optimization with automated drift correction enabled a robust detection of G6P changes in time series experiments down to a resolution of 10 min.     

Sigmoid diverticular abscesses: percutaneous drainage as an adjunct to surgical resection in 24 cases

Twenty-four patients with acute sigmoid diverticulitis and associated pelvic fluid collections seen on computed tomographic scans underwent percutaneous catheter drainage as an adjunct to surgical therapy. Fourteen of the 24 underwent a single-stage surgical procedure within 10 days of drainage. Five patients required two-stage surgical procedures because localized inflammatory changes precluded a primary resection despite the absence of a residual abscess at surgery. Two of the three remaining patients initially had no surgery, but they had recrudescences of their symptoms that required surgical drainage within 8 months. One patient in whom surgical resection was deferred remained asymptomatic 10 months after percutaneous drainage. A retrospective review of 87 patients undergoing surgery for diverticulitis suggested that the percentage of two-stage surgical procedures has decreased in the last 5-10 years, but there remains a substantial number of patients who might benefit from percutaneous catheter drainage of diverticular abscess of the sigmoid colon.     

Malignant Mixed Mesodermal Tumour of the Uterus Initially Confined to a Polyp

A malignant mixed mesodermal tumour (MMMT) of the uterus, in a 68-year-old woman, was initially confined to an endometrial polyp. Despite the absence of myometrial invasion, the tumour metastasized to the omentum. This experience conflicts with previously reported cases. An aggressive approach to the management of these tumours is suggested.     

Cerebellopontine angle-petromastoid mass lesions: comparative study of diagnosis with MR imaging and CT

Capabilities of computed tomography (CT) and magnetic resonance (MR) imaging in the diagnosis of cerebellopontine angle-petromastoid (CPA-PM) lesions were compared in 75 patients. CT and MR demonstrated 95.8% and 98.7% of the lesions, respectively. MR was often more helpful for characterization of neuromas, epidermoid cysts, exophytic gliomas, and vascular lesions, while CT was usually more informative for meningiomas, metastases, and tympanomastoid cholesteatomas. A specific diagnosis could be made with MR for most types of lesions through use of relaxation parameters and characteristic morphologic changes. Size, shape, location, and contour of the lesions, however, were generally more helpful for differential diagnosis than relaxation times. With the exception of metastatic lesions, cholesteatomas, and some meningiomas, MR was usually more helpful than CT in defining the full extent of the lesions and their relationships to contiguous structures. MR, because of its high accuracy in lesion detection, characterization, and localization, is a suitable primary diagnostic modality for evaluating patients with suspected CPA-PM lesions.     

Macroporous hydrogel membranes for a hybrid artificial pancreas. I. Synthesis and chamber fabrication

We report development of special macroporous semipermeable membranes and diffusion chambers made of polymerized 2-hydroxyethyl methacrylate (pHEMA), synthesized specifically to enclose living insulin-producing pancreatic islet cells for the treatment of diabetes. This material was selected to minimize the fibrotic encapsulation which has limited hybrid artificial pancreas efforts with other membranes, including Millipore and Nuclepore filters. The pore density and pore size distribution were dependent on the ratio of water to HEMA monomer and also on the crosslinker (EGDMA) concentration. A macroporous membrane resulted only when the ratio of water/HEMA monomer was greater than 50%. 125I-insulin permeability was studied in vitro. A technique is also described to fuse the membranes to form diffusion chambers used for implantation into diabetic rats.