Nuclear magnetic resonance proton imaging of bone pathology

Thirty-two patients with diversified pathology were examined with a supraconductive NMR imager using spin echo with different TR and TE to obtain T1 and T2 weighted images. They included 20 tumors (12 primary, eight metastasis), six osteomyelitis, three fractures, two osteonecrosis, and one diffuse metabolic (Gaucher) disease. In all cases except for the stress fractures, the bone pathology was clearly visualized in spite of the normal lack of signal from the compact cortical bone. Nuclear magnetic resonance (NMR) imaging proved to be at least as sensitive as radionuclide scintigraphy but much more accurate than all other imaging procedures including computed tomography (CT) and angiography to assess the extension of the lesions, especially in tumors extended to soft tissue. This is due both to easy acquisition of sagittal and coronal sections and to different patterns of pathologic modifications of T1 and T2 which are beginning to be defined. It is hoped that more experience in clinical use of these patterns will help to discriminate between tumor extension and soft-tissue edema. We conclude that while radionuclide scintigraphy will probably remain the most sensitive and easy to perform screening test for bone pathology, NMR imaging, among noninvasive diagnostic procedures, appears to be at least as specific as CT. In addition, where the extension of the lesions is concerned, NMR imaging is much more informative than CT. In pathology of the spine, the easy visualization of the spinal cord should decrease the need for myelography.     

Peracute streptococcal pyomyositis: report of two cases and review of the literature

Pyomyositis occurs infrequently in temperate climates. The fulminating peracute form caused by group A Streptococcus is exceedingly rare. We present two children with streptococcal pyomyositis. One child was admitted in septic shock and required intensive supportive care during the acute stage of his illness. Persistent swelling and tenderness of his left thigh presented a diagnostic problem, which was eventually resolved with the aid of computerized tomography. Despite appropriate antibiotic therapy from the onset of illness, surgical debridement of the affected muscle was necessary. The second child presented with pyomyositis of the left paravertebral muscles and signs of incipient shock but did well on antibiotic therapy alone.     

Diaper area skin microflora of normal children and children with atopic dermatitis.

In vitro studies established that neither cloth nor disposable diapers demonstrably contributed to the growth of Escherichia coli, Proteus vulgaris, Staphylococcus aureus, or Candida albicans when urine was present as a growth medium. In a clinical study of 166 children, the microbial skin flora of children with atopic dermatitis was compared with the flora of children with normal skin to determine the influence of diaper type. No biologically significant differences were detected between groups wearing disposable or cloth diapers in terms of frequency of isolation or log mean recovery of selected skin flora. Repeated isolation of S. aureus correlated with atopic dermatitis. The log mean recovery of S. aureus was higher in the atopic groups. The effects of each diaper type on skin microflora were equivalent in the normal and atopic populations.     

Ethical aspects of withdrawing/withholding renal replacement therapies on patients in acute renal failure in an intensive care unit

The majority of patients being treated for acute renal failure in intensive care units have multiple medical problems. Accordingly, the withdrawal of renal replacement therapies should be considered as part of a general decision about whether to initiate or continue with treatment per se. Several guidelines on withdrawing and withholding therapy have been produced and some common themes emerge: concerns to avoid euthanasia, potential for benefit, patient consent (shared decision‐making), team consensus/decision‐making, and the provision of appropriate palliative care and resource implications. Each of these is considered in turn, although the word limit for this paper does not permit detailed exposition.     

Response to treatment in panic disorder with associated depression

Thirty outpatients with panic disorder (PD) were treated at an anxiety clinic using a symptom-focused approach. Thirteen (43%) had no history of major depressive disorder (MDD), 12 (40%) had a history of secondary MDD, and 5 (17%) had history of primary MDD. The outcome was equally good in patients with no history of MDD (77% had good or excellent outcomes) and patients with a history of secondary MDD (83% had good or excellent outcomes). Patients with a history of primary MDD had the worst outcomes. These findings agree with earlier studies showing that secondary MDD does not adversely affect prognosis of patients presenting for treatment of PD.     

Folding and function of the myelin proteins from primary sequence data.

To explain how the myelin proteins are involved in the organization and function of the myelin sheath requires knowing their molecular structures. Except for P2 basic protein of PNS myelin, however, their structures are not yet known. As an aid to predicting their molecular folding and possible functions, we have developed a FORTRAN program to analyze the primary sequence data for proteins, and have applied this to the myelin proteins in particular. In this program, propensities for the secondary structure conformations as well as physical-chemical parameters are assigned to the amino acids and the pattern of these parameters is examined by calculating their average values, autocorrelation functions and Fourier transforms. To compare two proteins, their sequences are aligned using a unitary scoring matrix, and homologies are searched by plotting a two-dimensional map of the correlation coefficients. Comparison of the corresponding myelin basic proteins (MBP) and P0 glycoproteins (P0) for rodent and shark showed that the conserved residues included most of the amino acids which were predicted to form the alpha or beta conformations, while the altered residues were mainly in the hydrophilic and turn or coil regions. In both rodent and shark the putative extracellular domain of P0 glycoprotein displayed consecutive peaks of beta propensity similar to that for the immunoglobulins, while the cytoplasmic domain showed alpha-beta-alpha folding. To trace the immunoglobulin fold along the P0 sequence, we compared the beta propensity curve of P0 with that of the immunoglobulin M603, whose three-dimensional structure has been determined. We propose that the flat beta-sheets of P0 are orientated parallel to the membrane surface to facilitate their homotypic interaction in the extracellular space. An extra beta-fold in the extracellular domain of shark P0 compared with rodent P0 was found, and this may result in a greater attraction between the apposed extracellular surfaces and may account for a smaller extracellular space as measured by x-ray diffraction. A computer search of the myelin protein sequences for functional motifs revealed sites for N-glycosylation, phosphorylation, nucleotide binding, and certain enzyme activities. We note especially that there are potential nucleotide binding sites in proteolipid protein (PLP), MBP and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP). This is consistent with the experimental observations that PLP acts like an ionophore or proton channel when reconstituted into planar lipid bilayers, MBP binds GTP, and CNP catalyzes in vitro the hydrolysis of 2',3'-nucleotides into corresponding 2'-nucleotides.     

Methods for repeated recording in visual cortex of anesthetized and awake behaving infant monkeys.

This report describes methods for making repeated recordings from visual cortex in infant macaque monkeys (age range 5 weeks to 7 months) both under nitrous oxide anesthesia and in an alert behaving state. These methods permitted successful collection of single-unit data from inferior temporal cortex and other areas in a longitudinal fashion from individual infants. For the anesthetized experiments, modifications of our standard techniques for surgical preparation and maintenance of the animal in an anesthetized, artificially ventilated state permitted repeated recording sessions while assuring the animal's continued health and normal growth. Following implantation with an eye coil, monkeys as young as 5 weeks could be trained to perform a fixation task during alert recording sessions which were likewise performed on a repeated basis with maintained health and development. Further, comparison of results from anesthetized and awake recording sessions indicates that alert recording is preferable for collecting certain types of data from visual cortex in infant monkeys.