Isolation of an outer membrane hemin-binding protein of Haemophilus influenzae type b

Haemophilus influenzae is a heme-dependent bacterium. However, little is known of the heme-iron uptake mechanism in this organism. By using a batch ligand affinity chromatography method, a hemin-binding protein of 39,500 molecular weight was isolated from total membranes derived from H. influenzae type b grown under iron-depleted but not under iron-sufficient conditions. Detection of the hemin-binding protein in a whole-cell binding assay demonstrated a surface-exposed location. Competition binding experiments indicated that this hemin-protein interaction was specific, since only hemin or heme-containing proteins, such as human hemoglobin and bovine catalase, but not protoporphyrin IX, iron-loaded human lactoferrin, or transferrin, could abrogate binding. In a limited survey of other H. influenzae strains, an identical hemin-binding protein was isolated, implying that this polypeptide may be structurally and functionally conserved among strains.

Hemoaccess site infection

Infectious complications involving a hemoaccess graft or fistula are a significant cause of morbidity in patients on chronic hemodialysis. A review of 274 consecutive hemoaccess procedures identified 28 infections (an incidence of 10 per cent). Infections occurred in 27 polytetrafluoroethylene (PTFE) grafts. The predominant organism was Staphylococcus aureus. Partial excision resolved 14 of the 27 graft infections. The remaining 13 required complete removal. Surgical management required six arterial ligations and seven autogenous reconstructions. No limb ischemia or mortality was directly attributable to these procedures. One infection occurred in 48 autogenous fistulas (an incidence of 2 per cent). Although partial removal of an infected prosthesis was often sufficient, brachial artery ligation was well tolerated when required to control anastomotic infection.

Agricultural injuries in children in central Wisconsin

Agriculture is widely recognized as one of the most dangerous occupations in the United States. The risk of agricultural trauma extends beyond the adult work force to include farm children. During a 2-year study of agricultural trauma conducted at the Marshfield Clinic/St. Joseph's Hospital, 246 (26.9%) of all agricultural injury victims were children (age less than 19 years). Teenagers were at greatest risk, but there were also many injuries among preschool children under the age of 6 years. Injuries occurred most often during the summer months, on weekends, and during the evening hours from 6:00 PM to 10:00 PM. There were relationships between the body part injured and the age of the child as well as between the agent associated with the injury and the age and gender of the child. Preschool farm children are particularly liable to experience head and neck trauma and injuries resulting from falls. Any successful effort to address either the prevention or treatment of agricultural trauma will need to consider that children have a unique pattern of injuries that differs from that of adults.

Iron sources for Haemophilus ducreyi

The ability of various haem- and non-haem-iron-containing compounds to support the growth of iron-limited cultures of Haemophilus ducreyi was assessed in a plate bioassay. Only haemin or the haem-containing proteins, bovine haemoglobin, human haemoglobin and bovine catalase, but not equine cytochrome C111, were capable of serving as the sole exogenous iron source. Complexes of haptoglobin-haemoglobin and haem-serum albumin retained the ability to function as iron substrates. In contrast, no growth was observed with FeCl3, human lactoferrin and human transferrin. Siderophore production was not detected with a universal chemical assay. Outer-membrane-protein profiles derived from iron-starved cultures revealed four iron-regulated polypeptides of 65, 50, 45.5 and 40.5 Kda. These results indicate that haem can supply the requisite iron for growth of H. ducreyi.

P2 purinoceptor regulation of mucin release by airway goblet cells in primary culture

1. The effects of adenine analogues on mucin release by airway goblet cells have been examined in a hamster primary tracheal epithelial cell culture. 2. Adenosine, a P1 receptor agonist, had no effect on mucin release even at 2 mM, while ATP, a P2 receptor agonist, stimulated mucin release in a dose-dependent fashion with an apparent EC50 of 20 microM. The relative potency order among adenine nucleotides was ATP greater than ADP greater than AMP = adenosine. 3. ATP gamma S, a non-hydrolyzable analogue of ATP, was equipotent with ATP in stimulating mucin release. The potency order among some ATP analogues was ATP greater than 2-methylthio ATP greater than alpha, beta-methylene ATP greater than beta, gamma-methylene ATP. Reactive blue 2, a putative P2 gamma-purinoceptor antagonist, did not block the ATP-induced mucin release. 4. The present results indicate that mucin release by airway goblet cells is stimulated by extracellular ATP via P2 receptor-mediated mechanism. We suggest that this mechanism may be important in the physiological regulation of airway goblet cell mucin release in vivo.

Carotid endarterectomy for asymptomatic carotid stenosis: a ten-year experience with 120 procedures in a fellowship training program

Performance of carotid endarterectomy for asymptomatic carotid stenosis has been restricted during recent years because of concern of reported complications in as high as 10-15% of patients, as well as limited long-term data on stroke protection. During the last 10 years, we have studied immediate and long-term results of carotid endarterectomy for asymptomatic disease in 120 patients. Operations were performed by a clinical vascular fellow with a staff surgeon in attendance in 113 (94%) cases with the remainder performed by the staff surgeon. Patients' mean age was 66 years; 82% were men. Risk factors included hypertension (56%), smoking (52%), coronary artery disease (32%), diabetes (24%), and hypercholesterolemia (6%). Arteriographic severity of stenoses was 80-99% in 74%, 60-79% in 22%, and 40-59% in 4% of cases. Postoperative complications included two transient neurological events (1.7%). No permanent strokes or deaths occurred. Using the life table method, cumulative stroke rate was 4.5% for ipsilateral events and 7.3% for contralateral events, confirming the high degree of stroke protection afforded by carotid endarterectomy in this population. Since these results were accomplished in a fellowship training program, we regard adequacy of this experience as the most influential factor in accomplishing this record. Surgeons who are unable to achieve comparable results should consider abandonment of the procedure or an extended period of additional training.

Quantitative I-123-IMP brain SPECT and neuropsychological testing in AIDS dementia

We performed I-123-IMP SPECT brain imaging on seven mildly demented AIDS patients and seven normal subjects. In an attempt to detect and quantitate regions of decreased I-123-IMP uptake, pixel intensity histograms of normalized SPECT images at the basal ganglia level were analyzed for the fraction of pixels in the lowest quartile of the intensity range. This fraction (F) averaged 17.5% (S.D. = 4.6) in the AIDS group and 12.6% (S.D. = 5.1) in the normal group (p less than .05). Six of the AIDS patients underwent neuropsychological testing (NPT). NPT showed the patients to have a variety of mild abnormalities. Regression analysis of NPT scores versus F yielded a correlation coefficient of .80 (p less than .05). We conclude that analysis of I-123-IMP SPECT image pixel intensity distribution is potentially sensitive in detecting abnormalities associated with AIDS dementia and may correlate with the severity of dementia as measured by NPT.

Hypercalcemia in a patient with tuberculous mediastinal lymphadenopathy

We describe the case of a 48 year old Indian female with hypercalcemia due to tuberculosis. She presented with symptoms of hypercalcemia and chest radiographs showed bilateral hilar lymphadenopathy with normal lung fields. The diagnosis of tuberculosis was made histologically from biopsy of the enlarged hilar nodes. Her hypercalcemia resolved following one month of anti-tuberculous treatment. The prevalence of hypercalcemia in tuberculosis has been reported to be high in western series. There is, however, a paucity of local data on the subject. The presence of 1-alpha-hydroxylase-like activity in pulmonary alveolar macrophages with resulting increased formation of active vitamin D metabolites is the postulated mechanism of tuberculosis associated hypercalcemia.

Organ donation terminology: Are we communicating life or death?

The continued functioning of organ transplantation depends on obtaining the permission of the next of kin. This communication process between medical or transplant professionals and a donor family hinges heavily on the understanding of certain critical terms like brain dead, life support, and transplantation. Communication issues in obtaining organ donation consent were examined, with particular focus on what are literally life-and-death decisions. Using an experimental simulation methodology, data are offered in support of the claim that much miscommunication occurs in such situations. Directions for improving such communication by allaying latent fears and more carefully defining crucial terminology are offered.

Reduced dependency on arteriography for penetrating extremity trauma: influence of wound location and noninvasive vascular studies

Indications for arteriography in penetrating extremity trauma remain controversial. We reviewed our clinical experience in 454 patients (514 extremities) with penetrating trauma admitted during a prior 3 1/2-year period. Injuries were caused by stab wounds in 60 (11.7%) extremities and by gunshot wounds in 454 (88.3%) extremities. Thirty-three of the 60 stab wounds (55%) required urgent exploration, and 27 underwent arteriography. No arteriograms were positive for unsuspected arterial injury in this group. Forty-two of 454 gunshot wounds (9.3%) underwent mandatory exploration; arteriograms were performed on 412 extremities. Forty-four arteriograms (10.7%) demonstrated evidence of unsuspected arterial injuries. During the last year, randomly selected extremities (n = 23) have been studied with B-mode ultrasonography and segmental Doppler pressure measurements. Using the subsequent arteriography as the "gold" standard, sensitivity was 83% and specificity was 100%. Gunshot wounds were categorized according to location and positive arteriograms. Injuries to the lateral thigh and arm resulted in no positive arteriograms, while positive studies were observed in 11% of medial and posterior arm, 14% of antecubital fossa, 25% of forearm, 7.5% of medial and posterior thigh, 8% of popliteal fossa, and 26% of calf injuries. We recommend arteriography for gunshot injuries to identified high-risk areas, while clinical evaluation alone is accurate in all stab wounds to the extremities and gunshot wounds to the lateral thigh and outer arm. Preliminary data suggest expanded use of B-mode ultrasonography may further reduce our dependency on arteriography in these cases.

A case of Leigh's disease with initial manifestation of dystonia

A case of Leigh's disease (subacute necrotizing encephalomyelopathy) is reported with such noteworthy features as early onset, dystonia, paraparesis the presence of low attenuation areas in both basal ganglias on computerized tomography of the brain and the presence of a high signal intensity in both basal ganglias in T2 weighted image by MR. The electron microscopic findings of muscle biopsy are suggestive of pleoconial mitochondrial myopathy.

Neutral glycosphingolipids isolated from porcine corneas

Six neutral glycosphingolipids were isolated from porcine corneas using silicic acid column chromatography and preparative thin-layer chromatography. Five of these glycolipids were partially identified by gas-liquid chromatography. Two were glucosylceramides, two were lactosylceramides and one was tetrahexosylceramide containing galactose, glucose and N-acetylgalactosamine in the molar ratio of 2:1:1. Glucosylceramides were found to be the predominating component, with lactosyl- and tetrahexosylceramides being the minor constituents. Sphingosine was the major long-chain base in all fractions. The fatty acids of the corneal neutral glycosphingolipids were variable in chain length. This represents the first investigation of neutral glycosphingolipids in corneas of any species.

Penetrating extremity trauma: identification of patients at high-risk requiring arteriography

Indications for arteriography in patients with penetrating trauma to the extremities remain controversial. Some clinicians have recommended universal use of arteriography, whereas others prefer to rely on physical findings alone. To better define our indications for contrast studies, we reviewed clinical data on 306 patients (349 extremities) with penetrating trauma who were admitted during a prior 2-year period (1985 to 1987). Injuries were caused by stab wounds in 50 (14.3%) extremities and by gunshot wounds in 299 (85.7%) extremities. Twenty-seven of the 50 stab wounds (54%) required urgent exploration based on physical findings, whereas 23 underwent arteriography. None of these studies showed unsuspected arterial injury. Twenty-nine of 299 gunshot wounds (9.7%) underwent mandatory exploration, and arteriograms were performed on 270 extremities; findings in 30 studies (11.1%) were positive for unsuspected arterial injuries. Gunshot wounds were categorized according to location and number of arteriograms with positive results. Arteriograms of lateral thigh and upper arm injuries resulted in no positive outcomes. Positive study results were recorded in 22.9% of calf injuries, 20% of forearm and antecubital injuries, 9.5% of popliteal fossa injuries, 9.0% of medial and posterior thigh injuries, and 8.3% of medial and posterior upper arm injuries. We recommend arteriography for penetrating injuries to these high-risk areas. However, clinical evaluation alone is accurate for identification of arterial trauma with lateral thigh or upper arm wounds and stab wounds to the extremities.

Serum levels of soluble interleukin-2 receptor in pulmonary tuberculosis

It is well known that the activation of cell mediated immunity has an important role in the pathogenesis of pulmonary tuberculosis and the production of the protective immunity against Mycobacterium tuberculosis. During the activation of T-cell by Interleukin-1 released from the macrophage, not only Interleukin-2 but also the soluble Interleukin-2 receptor (sIL-2R) molecule is released into the extracellular fluid. In vitro study reveals that the level of this sIL-2R is well correlated with the degree of activation of the T-cell. We therefore carried out this study to evaluate the significance of the serum IL-2R level in determining the disease activity of pulmonary tuberculosis. The level of sIL-2R was measured by sandwich ELISA method. The level of sIL-2R in 42 patients with bacteriologically -proven active pulmonary tuberculosis (29 far and moderately advanced pulmonary tuberculosis, age: 30.3 +/- 10.3 yrs; 13 minimal pulmonary tuberculosis, age: 34.4 +/- 15.3 yrs) was 1111 +/- 424 mu/ml, which was significantly higher than the normal control group (age: 31.0 +/- 9.9 yrs) (365 +/- 143 mu/ml) and inactive pulmonary tuberculosis group (age: 37.3 +/- 16.9 yrs) (465 +/- 131 mu/ml). But there was no significant difference between 29 patients with advanced pulmonary tuberculosis (1138 +/- 405 mu/ml) and 13 patients with minimal pulmonary tuberculosis (1051 +/- 474 mu/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital and perinatal lesions

Most congenital abnormalities can be traced to defects occurring at a specific stage during embryologic development. Anatomic deformities of the ventricular system and brain surface are visualized and myelination of the white matter is well evaluated on MR scans so that congenital abnormalities may be differentiated from perinatal lesions. MR imaging is often the only imaging modality required for complete assessment of abnormalities in the neonatal period.

Penicillin-binding proteins of Haemophilus ducreyi

The penicillin-binding protein (PBP) profile of Haemophilus ducreyi was determined by a whole-cell-labeling assay. Only two major PBPs, of molecular weights 90,000 (PBP 1) and 38,500 (PBP 2), were detected in six of eight strains studied. Competition binding experiments and the attendant morphological effects suggested that PBP 1 was either a functional amalgamation or a lack of resolution of two proteins equivalent to PBPs 1 and 3 of Escherichia coli.

Iron resistance of hepatic lesions and nephroblastoma in rainbow trout (Salmo gairdneri) exposed to MNNG

Histochemical markers are important for the early detection of chemically initiated neoplasia in experimental animal studies. The marker, iron resistance, was evaluated in the Shasta strain of rainbow trout (Salmo gairdneri). Twenty-one-day-old trout embryos were exposed to 100 ppm aqueous N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for 30 min in a static water bath. Fish were fed a semipurified diet, and sampled monthly from the 4th to the 9th month. Two days before sampling, fish were iron-loaded with a single ip dose of 0.30 mg iron dextran/100 g body weight. Livers and kidneys were conventionally processed to paraffin sections for iron, or hematoxylin and eosin (H&E) staining. Normal hepatocytes accumulated iron in pericanalicular locations, but in hepatocytes from carcinogen-altered foci and tumors, iron staining was clearly reduced or absent. Normal renal tubule cells exhibited slight to moderate iron staining, while those from nephroblastoma were iron resistant. These results establish iron resistance as a property of preneoplastic and neoplastic trout hepatocytes and nephroblastoma cells for the first time. Iron resistance may offer a practical histochemical marker in experimental fish models of hepatocellular carcinoma and nephroblastoma.

31P spectroscopy in thrombolytic treatment of experimental cerebral infarct

Ischemic changes produced by autogenous clot embolization of intracranial arteries were monitored by continuous surface-coil 31P spectroscopy in 12 rabbits: six were used as controls and six were treated intravenously with tissue-type plasminogen activator. The animals were sacrificed and the brains were fixed with intravital stains. The results indicate that spectral changes are reversible only when thrombolysis therapy is started within 30 min after ischemic changes are detected. The improvement of the 31P spectrum correlated with postmortem changes.

Identification and comparative analysis of the lactoferrin and transferrin receptors among clinical isolates of gonococci

Neisseria gonorrhoeae expresses receptors for both lactoferrin (LF) and transferrin (TF). To determine whether qualitative or quantitative changes in these receptors, or both, correlate with the pattern of disease due to N. gonorrhoeae, a dot binding assay with whole cells was used to measure the absolute receptor levels expressed during iron-limited growth of strains isolated from asymptomatic patients and patients with urethritis, cervicitis, pelvic inflammatory disease and disseminated infection. Lactoferrin and transferrin receptor complexes were purified by affinity chromatography and their protein profiles were compared. The molecular weights of the LF and TF receptor complexes from a representative sample of gonococci were homogeneous. We conclude that there is no relationship between the LF and TF receptor levels and disease manifestation, auxotype or serotype.

Computed tomography versus magnetic resonance imaging of the brain. A collaborative interinstitutional study

A retrospective study (1983-1984) of magnetic resonance imaging (MRI) and computed tomography (CT) examinations in 471 patients with known pathology in the brain and craniocervical junction was conducted in order to determine the relative efficacy of MRI versus CT. All MRI examinations involved slice thickness greater than 10 mm, and only single-slice single-echo or multislice single-echo imaging techniques were available. These studies were evaluated independently by two neuroradiologists from a panel of six for anatomic abnormalities, lesion contrast, and radiologist's impression. Results, which excluded microadenomas of the pituitary and approximately 9% of studies in which consensus was not achieved by the readers, were as follows: (1) 14% of the studies were positive on MRI but normal on CT; (2) in 55% of the studies, MRI was better than CT; (3) MRI was equal or better than CT in 95% of the studies; and (4) CT was better than MRI in 5% (21/421) of the examinations. There were no patients in this series where CT was positive but MRI missed the abnormality.

Comparative analysis of the transferrin and lactoferrin binding proteins in the family Neisseriaceae

Intact cells of several bacterial species were tested for their ability to bind human transferrin and lactoferrin by a solid-phase binding assay using horseradish peroxidase conjugated transferrin and lactoferrin. The ability to bind lactoferrin was detected in all isolates of Neisseria and Branhamella catarrhalis but not in isolates of Escherichia coli or Pseudomonas aeruginosa. Transferrin-binding activity was similarly detected in most isolates of Neisseria and Branhamella but not in E. coli or P. aeruginosa. The expression of transferrin- and lactoferrin-binding activity was induced by addition of ethylenediamine di-o-phenylacetic acid and reversed by excess FeCl3, indicating regulation by the level of available iron in the medium. The transferrin receptor was specific for human transferrin and the lactoferrin receptor had a high degree of specificity for human lactoferrin in all species tested. The transferrin- and lactoferrin-binding proteins were identified after affinity isolation using biotinylated human transferrin or lactoferrin and streptavidin-agarose. The lactoferrin-binding protein was identified as a 105-kilodalton protein in all species tested. Affinity isolation with biotinylated transferrin yielded two or more proteins in all species tested. A high molecular mass protein was observed in all isolates, and was of similar size (approximately 98 kilodaltons) in all species of Neisseria but was larger (105 kilodaltons) in B. catarrhalis.

Metaplastic pancreatic cells in liver tumors induced by diethylnitrosamine

Metaplastic pancreatic cells have been infrequently observed in fish liver tumors induced by chemical carcinogens. An investigation with nitrosamine-exposed trout was undertaken to characterize the relationships of metaplastic pancreatic cells with other cell types. Eight-week-old rainbow trout (Salmo gairdneri) were fed a control diet or diets containing 500 ppm beta-naphthoflavone (BNF), 2000 ppm indole-3-carbinol (13C), or 100 ppm Aroclor 1254 (PCB) for 6 weeks. The fish were then exposed to 250 ppm diethylnitrosamine for 24 hr in an aqueous aquarium bath and reared on control diet for 39 weeks postexposure. Livers were excised, processed to paraffin sections, and stained with hematoxylin and eosin for histological evaluation. Metaplastic pancreatic cells were found only in tumors. Of the tumors with metaplastic pancreatic cells, 100/105 (95.2%) contained neoplastic cholangiolar components. Only 5/105 (4.76%) were hepatocellular carcinomas. 13C pretreatment inhibited the incidence of cholangiolar tumors (cholangioma 3.6% vs 31.3%, cholangiocarcinoma 3.6% vs 13.0%) and metaplastic pancreatic cells (5.1% vs 19.1%), whereas BNF and PCB had no effect. A hepatocellular origin for metaplastic pancreatic cells is supported. Cholangiolar neoplasia is associated with the expression, growth, or survival of metaplastic pancreatic cells in liver tumors. Hepatocarcinogenicity should not be described entirely by hepatocellular events since cholangiolar and metaplastic pancreatic cells can respond associatively to carcinogens and dietary modulators.

Specificity of the lactoferrin and transferrin receptors in Neisseria gonorrhoeae

Lactoferrin (LF) and transferrin (TF) are postulated to be important physiological sources of iron for Neisseria gonorrhoeae. A dot binding assay involving the use of gonococcal total membranes derived from cells grown in iron-limited conditions demonstrated the presence of separate receptors for LF and TF. The ligand and functional specificities of these receptors were examined in competition-binding and growth experiments. The results indicate that the LF and TF receptors are highly specific for the human protein, suggesting that this property may be partially responsible for conferring the human host specificity of N. gonorrhoeae.

Modulation of diethylnitrosamine-induced hepatocarcinogenesis and O6-ethylguanine formation in rainbow trout by indole-3-carbinol, beta-naphthoflavone, and Aroclor 1254

Rainbow trout were fed a diet containing indole-3-carbinol (2000 ppm), beta-naphthoflavone (500 ppm), or Aroclor 1254 (100 ppm) for 6 weeks before a single 24-hr exposure to an aqueous solution of 250 ppm diethylnitrosamine (DEN). The fish were killed 42 weeks later to determine the carcinogenic response. DEN exposure produced an 80.2% incidence of liver tumors and an average of 3.47 tumors per tumor-bearing fish, whereas no tumors were detected in the sham-treated control fish. Tumor induction was inhibited by indole-3-carbinol (27.5% incidence, 1.89 tumors per tumor-bearing fish) but enhanced by beta-naphthoflavone (91.8% incidence, 3.60 tumors per tumor-bearing fish). Aroclor 1254 had no effect on DEN-induced hepatocarcinogenesis (80.0% incidence, 3.03 tumors per tumor-bearing fish). The effects of these modulators on O6-ethylguanine and 7-ethylguanine formation (measured by HPLC and fluorescence spectrophotometry) were examined. Liver DNA ethylguanine levels were reduced in indole-3-carbinol-pretreated fish and increased in beta-naphthoflavone-pretreated fish compared to untreated controls after DEN exposure. Aroclor 1254 pretreatment had no significant effect on DNA ethylguanine formation. Similar O6-ethylguanine to 7-ethylguanine ratios were found among the control and treated groups. The results of this study indicate that modulation of DEN hepatocarcinogenesis by indole-3-carbinol and beta-naphthoflavone may be mediated by their effects on O6-ethylguanine formation and, therefore, on the initiation phase of carcinogenesis.

Occurrence of an unusual amount of an odd-numbered fatty acid in glycosphingolipids from human cataracts

Human cataractous glycosphingolipids were isolated and purified according to previously established procedures. Fatty acid analyses of the purified glycosphingolipid revealed the presence of a significant amount of an odd-chain fatty acid. This was confirmed by methane (CH4) chemical ionization mass spectrometry, which showed characteristic ions at m/z 397, 425, 437, and 365. These ions facilitated the determination of molecular weight and the assignment of C25:0 (n-pentacosanoic acid) to this fatty acid in question. This may be the first time that such an unusual distribution of a single odd-chain fatty acid has been shown to occur in glycosphingolipid from any tissue.

Dural and carotid cavernous sinus fistulas. Diagnosis, management, and complications

Carotid cavernous sinus fistulas (CCSFs) are a rare entity occurring as a result of head trauma and also spontaneously. The major threat from these fistulas is loss of vision. The authors reviewed 18 cases of direct and dural CCSFs seen over the last 10 years and compared our results with 553 cases treated in the literature. Seventy-one percent of our patients with direct CCSFs had successful balloon embolization. In the literature, successful closure of direct CCSFs has ranged from 58 to 100%. As experience with embolization techniques broadens, morbidity and mortality is reduced. The clinical features, diagnostic procedures, therapeutic options, and complications of treatment of CCSFs are discussed.

Magnetic resonance imaging of peri-aqueductal lesions

Fourteen lesions in the peri-aqueductal region were evaluated by 0.5T magnetic resonance imaging (MRI) and computed tomography (CT). Fifty normal magnetic resonance studies of the same region were reviewed. The aqueduct of Sylvius is seen in the midline sagittal MRI sections in all normal patients. It is not usually visible in cases of benign stenosis but may be seen in membranous obstruction. Benign stenosis is distinguished from neoplastic obstruction by the lack of increased signal on T2 weighted techniques. Blood within pineal tumours is easily detected and may be differentiated from lipomas, cystic lesions and solid tumours of the brain stem. Arachnoid cysts are also visible in MRI scans.

No sex-related differences in human corpus callosum based on magnetic resonance imagery

Recent studies have reported sex-related differences in the morphology of the human corpus callosum in cadaver brains. To further investigate these reports, sagittal magnetic resonance image scans from 40 male and 40 female subjects were used to compare callosal morphology. Relative callosal measurements were calculated by morphometric analysis. Significant sex-related differences were not found for callosal areas, maximal callosal width, or callosal curvature. These results indicate the need for further study before claims of sex-related differences can be accepted.

Craniotomy versus transsphenoidal excision of large pituitary tumors: the usefulness of magnetic resonance imaging in guiding the operative approach

Fifteen patients with large pituitary tumors were studied with computed tomography (CT) and magnetic resonance imaging (MRI). CT was performed using General Electric 8800 and 9800 scanners (General Electric Co., Medical Systems Division, Milwaukee, Wisconsin). MRI was performed utilizing a Technicare superconducting scanner (Technicare, Cleveland, Ohio) at 0.5 tesla. Based on the operative findings, the tumors were divided into two groups. Tumors in Group 1 (n = 12) were described by the surgeon as soft or partially necrotic and easily removed by suction and curettage. Tumors in Group 2 (n = 3) were firm and required sharp dissection or the laser for removal. The tumors were divided into four categories based on MRI signal: (a) isointense with surrounding brain on spin echo (SE) 30 and SE 90, (b) increased signal intensity on SE 30 and SE 90, (c) decreased signal intensity on SE 30 and increased signal intensity on SE 90, and (d) isointense signal on SE 30 and increased signal intensity on SE 90. All three of the firm tumors were isointense with brain on MRI appearance. The tumor consistency (firm vs. soft) was not differentiable on CT scan. The transsphenoidal approach is less satisfactory than craniotomy in cases of firm, fibrous pituitary tumors. Based on our preliminary data, if the MRI signal in the tumor is isointense, then the surgeon should be prepared to deal with a fibrous tumor and might elect a transcranial rather than a transsphenoidal approach.

The diversity of neurologic events in systemic lupus erythematosus. Prospective clinical and computed tomographic classification of 82 events in 71 patients

To investigate outcome and pathophysiology of central nervous system (CNS) systemic lupus erythematosus (SLE), we prospectively codified all cases of CNS SLE. Eighty-two events occurred in 71 patients. Four events in four patients were due to infection and were excluded. Twelve events occurred in 11 women with positive antinuclear antibody but negative anti-DNA antibody test reactions and no other manifestation of SLE. Of the remaining 66 events (56 patients), 26 events were "isolated" and 40 "complex." Non-CNS SLE was "active" during 47 events and "inactive" during 19 events. "Isolated" CNS events were equally likely in clinically "active" and "inactive" SLE. Patients with active SLE were as likely to have an episodic or remittent course as were patients with inactive SLE. "Complex" events, however, were more likely to have favorable outcome than were "isolated" events. "Isolated" events without focal CT abnormalities, the only component of CNS SLE that can be called diffuse lupus encephalitis, accounted for only 20% of all neurologic events.

Periventricular hyperintensity as seen by magnetic resonance: prevalence and significance

Periventricular hyperintensity was identified using long repetition and echo times in spin-echo magnetic resonance imaging of patients with white-matter disease (e.g., multiple sclerosis) caused by local demyelination and in hydrocephalic patients caused by transependymal migration of spinal fluid. A review of 365 consecutives studies revealed that some degree of periventricular hyperintensity is present in most patients (93.5%) regardless of diagnosis. Mild periventricular hyperintensity was seen in patients with no other evidence of intracranial pathology. Periventricular hyperintensity is a normal finding that should not be considered indicative of either demyelinating disease or hydrocephalus. More extensive and severe periventricular hyperintensity is associated with intracerebral pathology, but the finding often is nonspecific. For example, mild periventricular edema from hydrocephalus is impossible to differentiate from the increased periventricular hyperintensity seen in patients with multiple white-matter lesions. Thus, the pattern of periventricular hyperintensity has proven to be of limited value in the clinical assessment of hydrocephalic patients.

Isolation and identification of sialic acids from the gangliosides of human cataracts

The sialic acid components of gangliosides isolated from human cataracts are verified and confirmed to be N-acetylneuraminic acid by combined thin-layer and gas-liquid chromatography techniques.

MRI of optic chiasm and optic pathways

Eight verified lesions of the optic chiasm were examined on 0.5 T magnetic resonance (MR) and GE 9800, 8800 computed tomographic (CT) scanners. Enlargement of the optic chiasm was demonstrated in all cases. There was some change of MR signal compared with brain in all but one case, which had no resemblance to contrast enhancement on CT scans. The signal was specific for hematoma in one case. Abnormal signal, probably signifying tumor spread into the optic radiation, was detected on T2-weighted images in one case. The resolution of MR scans is similar or superior to CT, and sagittal views are most useful in evaluating lesions in this location.

MRI of the central nervous system in neonates and young children

Twelve normal neonates and young children, ages 32 weeks gestation to 20 months, and 22 abnormal children up to four years old had MRI scans using a 0.5 T superconducting scanner. A faint signal that was presumed to be myelin was detected in the thalami at 32 weeks; myelination of the occipital lobes was present at full term, and visible throughout the hemispheres by 8 weeks of age. Anatomical locations of congenital lesions were well demonstrated, especially in sagittal views. The signal changes of perinatal abnormalities, such as hemorrhage and hemiatrophy, were often specific. Abnormal position of the spinal cord, spinal lipomas, and other congenital lesions were also well visualized.

MRI assessment of human callosal surgery with neuropsychological correlates

MRI imaging using recovery and spin-echo techniques was carried out on three patients after surgical section of the corpus callosum to control intractable epilepsy. The scans revealed that the total callosotomy had been obtained in two patients, while partial sparing of splenial and rostral fibers was seen in the third.

Concurrent osteoblastoma and aneurysmal bone cyst of the ethmoid sinus: case report

A unique case of osteoblastoma and aneurysmal bone cyst of the ethmoid sinus is reported. A causal relationship may exist between the two entities. The computed tomography appearance consisted of a dense lesion with a thin sclerotic rim containing a low-attenuation center, causing ethmoid sinus enlargement. Similar radiologic appearances are seen with other less rare pathologies.

Sellar and juxtasellar lesion detection with MR

We compared the effectiveness of magnetic resonance (MR) imaging and computed tomography (CT) in evaluating sellar and juxtasellar lesions. Fifty-five lesions were imaged with a Technicare 0.5-T superconducting MR imager and GE 9800 and 8800 CT scanners: 26 pituitary adenomas (including six microadenomas), six craniopharyngiomas, two empty sellae, five meningiomas, four optic chiasmal gliomas, five hypothalamic gliomas, two giant aneurysms, and one each of teratoma, gasserian ganglion neuroma, histiocytoma, cholesteatoma, and metastases. Although CT scans showed the abnormalities in most cases, MR was superior in delineating distortions of the optic chiasma and other suprasellar structures, and in demonstrating the status of the carotid arteries. MR can reveal fat, hematoma, and cyst and can be used to differentiate the pathologic features of many lesions. Microadenomas that do not enlarge the sella were not demonstrated with current MR techniques.

Essential trace metals and specific organ weights in diet-restricted and ad lib-fed rats

Manganese, copper, iron, zinc, and specific organ weights (relative to body weight) of the heart, liver, and kidney were compared between a 65% diet-restricted group and an ad lib-fed control group of young male Sprague-Dawley rats. Elevated concentrations of Cu (12%) in the liver, and of Mn (12-26%) and Fe (17-69%) in all three organs, occurred in the diet-restricted group. Specific heart weight was unchanged despite the 40% difference in group body weights. Specific liver weight decreased 13% and specific kidney weight increased 13%.

MR imaging of syringomyelia and hydromyelia

The relative effectiveness of plain computed tomography (CT), metrizamide CT, conventional myelography, and magnetic resonance (MR) imaging was compared for the examination of cystic spinal cord lesions. Intramedullary cavities in 18 patients were demonstrated by MR imaging: cavities were uncomplicated in 13 patients, associated with spinal tumors in two, and studied after occipital craniectomy for treatment of Chiari malformation and syringomyelia in two. Cavities were shown by MR imaging in all enlarged spinal cords, but a cavity was shown in only one of four small cords. The rostral limits of the cavities were demonstrated better than were the caudal extensions. Ventricular communication was not demonstrated. Chiari malformation was shown only in cavities that did not involve the medulla. Syringes associated with tumor were indistinguishable from uncomplicated cavities, but the tumor had abnormal signal on long spin-echo sequences in two cases. Cystic cord tumor (one case) had an inhomogeneous appearance. Caudal displacement of the cerebellar hemisphere through the surgical defect associated with compression of the fourth ventricle was shown in two cases after posterior fossa craniectomy. Thirteen patients were studied with metrizamide CT also. MR imaging proved to be as accurate as metrizamide CT in the diagnosis of intramedullary cavities that result in spinal cord enlargement, but it was less sensitive in detecting cavities within normal-sized or diminished spinal cords. It had the advantage that tumor tissue could be distinguished from associated syrinx cavities by differences in signal characteristics; and cerebellar ectopia was evaluated easily on sagittal MR views.

Simultaneous determination of brachial and femoral arterial pressures during reactive hyperemia and papaverine vasodilation

Accurate assessment of aortoiliac occlusive disease often requires direct intraarterial pressure determination. Since these measurements may alter systemic pressure, brachial arterial pressure (BAP) and femoral arterial pressure (FAP) were obtained simultaneously to quantitate these changes. BAP and FAP were measured at rest, and then during vasodilation produced by postischemic reactive hyperemia and intra-arterial injection of papaverine. The gradient between FAP and BAP was used to assess the significance of an aortoiliac stenosis. Sixty-eight observations were performed in 19 limbs. During reactive hyperemia (n = 28), BAP was 142 +/- 7 mm Hg, which was not significantly different from the baseline BAP of 142 +/- 5 mm Hg. However, during thigh tourniquet inflation, BAP increased significantly to 158 +/- 7 mm Hg. Following papaverine injection (N = 21) BAP was 144 +/- 8 mm Hg, which was significantly different from both the baseline BAP (150 +/- 6 mm Hg) and the preinjection BAP (156 +/- 6 mm Hg). Postischemic reactive hyperemia and papaverine vasodilation produced comparable brachial to femoral pressure gradients. Use of baseline BAP is recommended for calculating gradients during reactive hyperemia, since the BAP is significantly elevated during tourniquet occlusion. Simultaneous recording of brachial and femoral pressures is recommended with intra-arterial papaverine injections, since the BAP varies significantly throughout the examination.

Reoperation for sepsis

A retrospective study of 50 patients undergoing reoperation for sepsis was performed to evaluate the ability of commonly available clinical and laboratory tests to predict the findings at reoperation and the outcome after operation. The influence of multiple organ failure on these parameters was also studied. No laboratory finding helped to predict operative findings. Computed tomographic scanning (80% accurate) was the most helpful radiographic procedure. A low total lymphocyte count and a high serum creatinine level both predicted a fatal outcome. No single organ failure or combination predicted a positive reexploration. Infection was found in 75 per cent of patients with multiple organ failure and 79 per cent of patients who did not have this syndrome. Patients having three-organ failure did have a significantly higher mortality. The mortality of a negative reexploration was 18.2 per cent, slightly lower than the 28.2 per cent mortality of patients with a positive exploration. No patient without organ failure died. The authors conclude that laboratory tests are not helpful in predicting the presence of infection on reexploration, that the decision to reoperate is one based primarily on clinical judgment, and that if reoperation is performed before the development of organ failure, the risk associated with a negative exploration is worth taking.