The computed tomographic appearance of the spinal cord in diastematomyelia

The myelographic and computed tomographic findings in 10 patients with diastematomyelia were reviewed. In all patients, including seven with osseous spurs, the hemicords were smaller than the normal cord above or below the cleft. The narrow hemicords distinguish diastematomyelia from diplomyelia.

Association of respiratory virus infections with sudden infant death syndrome

From September, 1974, to September, 1979, 488 cases of sudden infant death syndrome (SIDS) in Melbourne were studied for evidence of viral infection. One hundred and eighty-eight infants (39%) yielded one or more viruses, with respiratory viruses being detected in 102 cases (21%). Further evidence of a respiratory virus association with SIDS was obtained by comparing the monthy respiratory virus isolation rates at the Royal Children's Hospital from 1973 to 1979 with the incidence of SIDS in the same period. A highly significant correlation was obtained between these isolation rates and the incidence of SIDS, which suggests that respiratory viruses play a role in SIDS in Melbourne.

Microbial Production of 4,4′-Dihydroxybiphenyl: Biphenyl Hydroxylation by Fungi

Of 15 species of fungi examined for their ability to hydroxylate biphenyl, 10 produced 4-hydroxybiphenyl. Seven of the 10 also produced 4,4′-dihydroxybiphenyl. The most efficient strains, Absidia pseudocylindrospora NRRL 2770 and Absidia sp. NRRL 1341, were more closely examined to determine their growth characteristics and the kinetics of biphenyl hydroxylation in batch fermentation. In the absence of biphenyl, A. pseudocylindrospora 2770 and Absidia sp. 1341 grew about as rapidly and efficiently in a defined glucose minimal medium as in a complex medium. Substrate yield coefficients for glucose in both media were 0.4 to 0.5 g of biomass per g of glucose, and the specific growth rate was about 0.17 h −1 (doubling time, about 4 h). In this unoptimized system, 10 to 15 g of biomass per liter (dry weight) could be produced, using a defined salt solution and glucose as sole carbon and energy source. In the presence of biphenyl, growth was inhibited, more so for strain 1341 than for strain 2770. However, the specific activity for biphenyl hydroxylation (milligrams of biphenol per gram of biomass) was about 3.5 times greater for strain 1341. Furthermore, biphenyl hydroxylation appeared to require the presence of an oxidizable carbon and energy source (and perhaps growth) to proceed and, at least for strain 1341, hydroxylation seemed to be more efficient in the complex medium.

Computed tomography in the diagnosis of herniated nucleus pulposus

In this study, the effectiveness of computed tomography(CT) in diagnosing herniated nucleus pulposus was evaluated. Sixteen CT examinations which were interpreted as positive for a herniated disk, and were intraoperatively confirmed, were reviewed. In all 16 patients, CT demonstrated posterior protrusion of the disk and displacement of anterior epidural fat. Calcification within the protruding disk was noted in several patients, and an extruded disk fragment identified by CT in two. In all cases, the CT findings correlated closely with the surgical findings. This study suggests that CT accurately demonstrates disk herniation.

Soft-tissue anatomy within the spinal canal as seen on computed tomography

The CT appearance of the vascular, ligamentous, and neural tissues in the spinal canal was studied in 50 patients and 5 cadavers. In some patients, iodinated contrast medium was first injected into the ascending lumbar veins, nucleus pulposus, or theca. Positive identification of spinal soft tissues on the CT image was made by reference to cadaver dissections. The spinal cord, nerves, root sheaths, retrovertebral plexus, epidural and basivertebral veins, posterior longitudinal ligament and ligamentum flavum, intervertebral disks, and vertebral arteries can be demonstrated by CT, indicating its value in the diagnosis of disease of the cord, disk, and epidural space.

Biological Process for Converting Naphthalene to cis -1,2-Dihydroxy-1,2-Dihydronaphthalene

A biological process for converting naphthalene to cis -1,2-dihydroxy-1,2-dihydronaphthalene (DHD) catalyzed by Pseudomonas putida strain 119 was optimized in flask experiments. These studies revealed the following: (i) P. putida 119 can propagate efficiently and produce DHD when supplied one of several carbon sources and naphthalene; (ii) maximum DHD production by P. putida 119 occurs in logarithmic-growth-phase cells and decreases at various rates in the stationary growth phase, depending upon the carbon source used; (iii) several analogs of salicylic acid can be used as effective inducers of naphthalene metabolism in P. putida cells growing on glucose; and (iv) the addition of chemical surfactants to naphthalene-cell ( P. putida 119) mixtures stimulates DHD production.

Improving visualization of the anterior subarachnoid space during cervical gas myelography

To improve definition of the spinal cord when it lies anteriorly, turning the patient from the lateral decubitus to the supine position and obtaining a horizontal-beam lateral radiograph of the cervical spine is recommended. Supine positioning permits improved visualization of the anterior subarachnoid space and evaluation of extradural lesions encroaching upon it, as well as abnormal fixation of the cord.

Tracheobronchitis and sudden infant death syndrome

In many infants who have died suddenly and unexpectedly post mortem examination reveals the presence of a non-suppurative tracheobronchitis. The role of the tracheobronchitis in the sudden death of the infant is not known. Analysis of a series of sudden infant deaths indicates that these infants die at an older age, i.e. over three months, and most frequently in colder months of the year. If, as suggested, these deaths constitute a distinct group, investigations regarding the mode of death should be undertaken separately from that in younger infants in whom no such lesions are found.

Computed tomography of the lumbar facet joints

Lumbar facet joints are difficult to image with conventional radiographic techniques. A series of 100 consecutive cases of low back pain and sciatica was examined with CT. Abnormal facet joints were found in 65. Abnormalities demonstrated by CT included osteophyte formation, hypertrophy of articular processes, articular cartilage thinning, vacuum joint phenomenon, and calcification of the joint capsule. In patients with sciatic or low back pain, CT is indicated to demonstrate treatable abnormalities of the facet joints.

Arteriovenous malformation simulating a cyst on computed tomography

Three cases are described in which an intracerebral arteriovenous malformation (AVM) was accompanied by a cystic component probably resulting from hemorrhage. The 3 patients gave a history of headaches. In cases of low-attenuating nonenhancing CT processes, an AVM must be considered.

The computed tomographic appearance of the normal pituitary gland and pituitary microadenomas

With the use of axial and coronal computed tomography (CT), the authors compared the density, contrast enhancement, and dimensions of normal pituitary glands and pituitary microadenomas. The normal gland appears homogeneous, nearly isodense with brain tissue, and it enhances uniformly. Its upper surface is concave downward or flat and its height 2-7 mm. The cavernous sinuses, the third, fourth, and sixth cranial nerves, the infundibulum, and the adjacent carotid arteries are well demonstrated by CT. Abnormal height and upward convexity of the gland are reliable signs of prolactinoma; abnormal density and enhancement are suggestive signs. CT findings in prolactin- and ACTH-secreting tumors may differ. CT is more sensitive and more specific than polytomography in the diagnosis of pituitary adenoma.

Computed tomography in Behçet disease

In Behçet disease, CT may demonstrate low attenuation mass lesions with or without contrast enhancement. Since neurologic involvement may precede the typical dermatologic manifestations, Behçet disease should be included in the differential diagnosis of intracranial mass lesions. A case is presented with central nervous system involvement.

CT resolution and diagnostic accuracy

To justify CT purchases and document certificates of need, the clinical effectiveness of CT scanners with different cost and resolution must be compared. The diagnostic accuracy and anatomic detail in three scanners with different resolution were studied. Seventeen patients were studied with both a first or a second generation CT scanner and a third-generation scanner. Appearance of normal and pathologic structures was compared. Cerebral sulci, corticomedullary discrimination, basal cistern vessels, and some pathologic lesions were seen in third generation images that were not seen in the others. Higher resolution scans provide significantly better anatomic detail and accuracy in detecting pathologic processes.

Radiological assessment of intramedullary spinal cord lesions

Gas myelography performed in the modified two-step technique has proven to be effective in defining the character and extent of intramedullary spinal cord lesions. A classification of four types of spinal cord abnormalities based primarily on the hydrodynamic changes induced during gas myelography assists in determining the need for specific neuroradiological and surgical procedures. The comparative value of other myelographic and pneumoencephalographic techniques is discussed.

CT detection of demyelinated plaques in multiple sclerosis

CT images and anatomic slices of two brains containing numerous demyelinated plaques were correlated. Demyelinated plaques smaller than 0.7 cm were not detected by CT. Some larger plaques were misinterpreted as normal structures. These and other considerations suggest that chronic cerebral demyelination cannot be excluded by negative nonenhanced CT scan.

A myelographic technique for cysts in the spinal canal and spinal cord

A collapsing cord in six patients with hydromyelia and a collapsing intraspinal arachnoid cyst in one patient are demonstrated. The authors describe the technique for two-position gas myelography and demonstrate that both intra- and extra-medullary intraspinal processes may collapse during myelography.

Ineffectiveness of prophylactic intrathecal methylprednisolone in myelography with aqueous media

The effectiveness of prophylactic intrathecal methylprednisone (MP) in preventing arachnoiditis from iocarmate myelography was studied. Monkeys were injected intrathecally with locarmate, MP, or a combination of the two. Twelve weeks later the severity of arachnoiditis was determined in each animal. There was no significant prophylactic effect of intrathecal MP on arachnoiditis from locarmate. Some arachnoiditis was found in control animals treated with MP alone.

Synthesis and activities of branched-chain aminoacyl-tRNA synthetases in threonine deaminase mutants of Escherichia coli

Valyl-, isoleucyl-, and leucyl-tRNA synthetase activities were examined in an Escherichia coli K-12 strain that possessed a deletion of three genes of the ilv gene cluster, ilvD, A, and C, and in a strain with the same deletion that also carried the lambdadilvCB bacteriophage. It was observed that the branched-chain tRNA synthetase activities of both strains were considerably less than those of the normal strain during growth in unrestricted medium. Furthermore, during an isoleucine limitation, there was a further reduction in isoleucyl-tRNA synthetase activity and an absence of the isoleucine-mediated derepression of valyl-tRNA synthetase formation in both of these mutants, as compared with the normal strain. In addition, it was observed that these branched-chain synthetase activities were reduced in steady-state cultures of several ilvA point mutants. However, upon the introduction of the ilv operon to these ilvA mutants by use of lambda bacteriophage, there was a specific increase in the branched-chain synthetase activities to levels comparable to those of the normal strain. These results support our previous findings that the stability and repression control of synthesis of these synthetases require some product(s) missing in the ilvDAC deletion strain and strongly suggest this component is some form of the ilvA gene product, threonine deaminase.

Severity of postmyelographic arachnoiditis and concentration of meglumine locarmate in primates

Myelography with meglumine iocarmate, a dilute meglumine iocarmate solution, or gas was performed in macaque monkeys. Twelve weeks later the animals were examined myelographically and histologically for evidence of arachnoiditis. Arachnoiditis in the animals treated with dilute meglumine iocarmate and gas was significantly less than in those treated with meglumine iocarmate.

A family study of coeliac disease

Studies by Thompson, 1 Carter et al, 2 MacDonald et al. and McCrae 4 have all shown a high familial frequency of coeliac disease (CD). The diagnostic criteria differed in each study; in Thompson's patients the diagnosis was based on clinical or historical data alone; in Carter's study response to a gluten-free diet was required, while in MacDonald's and McCrae's studies the diagnostic criteria included the demonstration of the lesion of CD by small bowel biopsy. In MacDonald's study some asymptomatic cases were discovered and a few of these had normal fat balance results. No hereditary pattern emerged from these studies though MacDonald postulated a dominant gene with variable penetrance while McCrae suggested that susceptibility to CD is inhereited multifactorially and that enviromental factors other than dietary gluten are of aetiological importance. Hoffman et al. 5, on the other hand, have described discordance for CD in identical twins.

Plasma renin activity in acute poststreptococcal glomerulonephritis and the haemolytic-uraemic syndrome

Plasma renin activity (PRA) was determined in 10 children with acute glomerulonephritis and in 10 with the haemolytic-uraemic syndrome (HUS). Low renin levels were found in the hypertensive children with acute nephritis, all of whom had evidence of fluid overload. The amount of this overload correlated directly with the degree of hypertension and inversely with PRA. All the hypertensive children with HUS had high levels of plasma renin, and the highest levels were found in those cases who were subsequently shown to have the more severe degree of renal arteriolar occlusion. The findings emphasize the importance of measures designed to reduce salt and water overloading in the management of hypertension in acute nephritis, while drugs which suppress plasma renin are more likely to control blood pressure in HUS. Estimation of PRA may provide a guide to the management of hypertension in acute renal insufficiency.

Control of arginine biosynthesis in Escherichia coli: inhibition of arginyl-transfer ribonucleic acid synthetase activity

In this study, we have extended our earlier observations indicating in vitro inhibition of arginyl-transfer ribonucleic acid synthetase (EC 6.1.13, arginine: soluble ribonucleic acid ligase, adenosine monophosphate) activity by the arginine biosynthetic precursors ornithine, citrulline, and argininosuccinate. Furthermore, we report evidence which suggest that this enzyme activity is inhibited by these arginine precursors in vivo and that this inhibition of activity results in a derepression of arginine biosynthesis.

Control of arginine biosynthesis in Escherichia coli: characterization of arginyl-transfer ribonucleic acid synthetase mutants

The arginyl-transfer ribonucleic acid (Arg-tRNA) synthetase (EC 6.1.1.13, arginine: RNA ligase adenosine monophosphate) mutants, exhibiting nonrepressible synthesis of arginine by exogenous arginine, were employed in studies of several biochemical properties. Two of these mutants possessed Arg-tRNA synthetases with a reduced affinity for arginine, and this enzyme of another mutant had a reduced affinity for arginine-tRNA (tRNA(arg)). The mutant possessing an Arg-tRNA synthetase with an altered K(m) for tRNA(arg) was found to have reduced in vivo aminoacylation of two of the five isoaccepting species of tRNA(arg) and complete absence of aminoacylation of one of the isoaccepting species.