A monoclonal antibody directed against the 97-kilodalton gonococcal hemin-binding protein inhibits hemin utilization by Neisseria gonorrhoeae

Neisseria gonorrhoeae expresses two hemin-binding proteins (HmBPs) of 97,000 and 44,000 in molecular weight. A murine monoclonal antibody (MAb) produced against the 97-kDa HmBP from N. gonorrhoeae PID543 specifically inhibited in a concentration-dependent manner the ability of hemin to promote growth. The anti-97-kDa HmBP MAb competitively inhibited binding of the 97-kDa HmBP to a hemin-agarose affinity column. In Western immunoblots, the MAb recognized the 97-kDa homologs from a limited survey of clinical gonococcal isolates. These results support the contention that the 97-kDa HmBP is involved in the gonococcal hemin acquisition pathway.

Percutaneous removal of a nonopaque silastic catheter from the pulmonary artery in two premature infants

A modified snare was made from a 0.016' guidewire and a 0.1-mm fishing string to remove a nonopaque Silastic catheter via a femoral vein approach in 2 premature infants at the 44th and 120th day of life, respectively. A foldover guidewire loop snare had failed in 1 infant before this technique was successfully applied.

Diagnostic testing for acute head injury in children: when are head computed tomography and skull radiographs indicated?

OBJECTIVE

Despite the frequent occurrence of head injury in children, there is no agreement about clinical screening criteria that indicate the need for imaging studies. This study was undertaken to provide information relevant to the choice of imaging modalities in children with acute head trauma.

METHODOLOGY

A prospective cohort of 322 children seeking care consecutively in an urban pediatric emergency department for nontrivial head injury was assembled. Skull radiographs, head computed tomography, and data forms including mechanism of injury, symptoms, and physical findings were completed for each child.

RESULTS

Intracranial injury occurred in 27 children (8%), whereas 50 (16%) had skull fractures. Of those with intracranial injury, 16 (59%) had normal mental status and no focal abnormalities, and 1 of those 16 required surgery for evacuation of an epidural hematoma. Six (38%) of the 16 were younger than 1 year, 5 of whom had scalp contusion or hematoma without other symptoms. Findings not significantly associated with intracranial injury were scalp contusion, laceration, hematoma, abrasion, headache, vomiting, seizure, drowsiness, amnesia, and loss of consciousness for less than 5 minutes. Findings associated with intracranial injury were skull fracture, signs of a basilar skull fracture, loss of consciousness for more than 5 minutes, altered mental status, and focal neurologic abnormality.

CONCLUSIONS

Intracranial injury may occur with few or subtle signs and symptoms, especially in infants younger than 1 year. The relative risk for intracranial injury is increased almost fourfold in the presence of a skull fracture, although the absence of a skull fracture does not rule out intracranial injury. The significance of nonsurgical intracranial injury in neurologically normal children needs further study.

Changes in plasma levels of lipids and lipoprotein composition in patients with Kawasaki disease

Studies on the response of plasma lipids and lipoproteins to Kawasaki disease are scarce so far. The purpose of this study was to investigate the changes in plasma levels of lipids and apolipoproteins as well as the composition of different lipoproteins in patients during the acute and convalescence phases of Kawasaki disease. The results showed that during the acute phase, the concentrations of plasma high density lipoprotein (HDL)-cholesterol, apolipoprotein A-I (apoA-I) and A-II (apoA-II) were significantly reduced. While the reduction of HDL-cholesterol was mainly related to the lowering of esterified and unesterified cholesterols in HDL2 during the acute stage of Kawasaki disease, most of which recovered during the subsequent convalescence phase. The plasma concentration of triglycerides was 46% higher in patients during the acute phase of Kawasaki disease than in the control subjects, which may be ascribed to the increase of triglycerides in very low density lipoprotein (VLDL), low density lipoprotein (LDL) and HDL2. The variables studied above did not appear to be independent parameters. The level of plasma apoA-I showed a stronger negative association with triglyceride concentration (r = -0.22) than apoA-II (r = -0.11) and HDL-cholesterol (r = -0.07). Furthermore, the levels of cholesterol, apoA-I and apoA-II in HDL2, but not in HDL3, were inversely correlated with the levels of triglyceride. We conclude that the temporary changes of lipid levels associated with Kawasaki disease results predominantly from alterations of lipoprotein composition.

Carotid arterial trauma: assessment with the Glasgow Coma Scale (GCS) as a guide to surgical management

Management of carotid arterial injuries associated with focal neurological deficit or altered state of consciousness (SCON) remains unresolved. Experience with these injuries in one particular hospital was reviewed and the Glasgow Coma Scale (GCS) utilized to assist with clinical stratification of these patients. A literature review was also conducted to better define indications for repair or ligation of carotid injuries. From 1978 to 1990, 34 patients with carotid arterial injuries were reviewed with reference to the GCS, focal deficit, hypotension, anatomic site and mechanism of injury. The literature from 1952 to 1993 was surveyed for carotid artery injuries (1316 patients). Outcome of treatment with or without repair was compared with pre-operative neurologic status. Thirty-four patients with injuries of the common (24) or internal (10) carotid arteries were managed with repair (68%), ligation (24%) or observation (9%). The SCON was normal in 18 patients; 16 patients (88%) underwent repair and all remained normal. All patients with GCS 9-14 regained a normal SCON after surgical repair, while 10 patients with GCS < 8 had repair (5), ligation (3), and non-operative management (2); five returned to normal, four died and one remained comatose. However, outcomes correlated poorly with management. Of 1316 patients cited in the surgical literature, patients with no deficit and patients with pre-operative deficits did significantly better after repair as compared with ligation (P<0.001). In comatose patients, management did not affect outcome. It is concluded that carotid arterial injuries should be repaired in patients with normal neurologic evaluation, focal pre-operative neurologic deficits and in patients with GCS > 9. Comatose patients with GCS < 8 do poorly regardless of management. The GCS provides an objective for stratification of patients with altered SCON who benefit from repair of carotid arterial injuries.

Transcatheter embolization of coronary artery fistula: a case report

Coronary artery fistula is rare, but it is the most common congenital coronary artery anomaly with hemodynamic significance. It usually causes no symptoms in young patients but may be associated with symptoms and complications in older patients. Surgery has been the traditional treatment. In this report, a 7-year-old girl who had a coronary artery fistula from the left circumflex coronary artery to the right atrium was successfully treated by percutaneous transcatheter technique.

MR imaging surface display of the cerebral cortex in children

The purpose of this study was to introduce the use of three-dimensional (3D) surface MR imaging display for clinical use. Surface display was created using images acquired with T1 magnetization prepared rapid acquisition gradient echo (MPRAGE) in 24 cases of migrational defects, cortical dysplasia and prenatal asphyxia. Schizencephaly and cortical dysplasia were pathologically confirmed. The precise configurations of cortical abnormalities, and their relation to the adjacent gyri and sulci were demonstrated. The topography of schizencephalic clefts was clearly defined. The appearance of ulegyria was characteristic and it was sometimes possible to differentiate polymicrogyria from pachygyria.

Aortic stenosis in children: 19-year experience

BACKGROUND

In the Taiwanese literature, few articles describe the pertinent features of aortic stenosis (AS). This study explores the features of AS in Chinese children.

METHODS

3808 children with congenital heart diseases have undergone cardiac catheterization at our institution over the past 19 years. Among them, 51 (1.3%) cases were AS. The clinical, electrocardiographic, echocardiographic and catheterization findings, the methods of treatment and outcomes were reviewed.

RESULTS

Valvular AS occurred in 39 children (76.5%), subvalvular AS in 5 (9.8%), and supravalvular AS in 7(13.7%). Male was predominant (M/F ratio, 2.6) except in supravalvular type. Forty-three patients had associated cardiovascular defects. Aortic regurgitation (AR) was the most common one. Most patients (56.9%) were asymptomatic. Classic symptoms included exertional dyspnea (17.6%), syncope (9.8%), and chest pain (7.8%), etc. Left ventricular hypertrophy was noted in 31.2% of cases. The mean duration of follow-up was 3.9 +/- 3.4 years. Ten patients received open-heart surgery and 2 received balloon dilation. The pressure gradients across the stenotic area dropped from 95.3 +/- 29.3 to 51.4 +/- 35.8 and 53.1 +/- 12.3 mm Hg in early and late Doppler follow-up studies, respectively (p < 0.05). The average gradient increased from 36.9 +/- 25.3 to 40.8 +/- 32.6 mm Hg in nonsurgical patients. The result was insignificant. No mortality occurred following open-heart surgery. One child expired due to heart failure after the ligation of the patent ductus arteriosus and dilation of the stenotic aortic valve on the surgical table under general anesthesia. Autopsy revealed valvular rupture. In the nonsurgical group, no mortality occurred, but one patient was brought home by parents in critical condition and later died.

CONCLUSIONS

We found that some clinical features of AS in Chinese children were different from those in occidental populations. (1) The incidence of AS was relatively low. (2) Subvalvular AS was the least common type in contrast to supravalvular AS in western studies. (3) Male predominance was not present in the supravalvular type, which lacked sexual proclivity. (4) Williams syndrome was a more frequently associated anomaly. Turner syndrome was not present in our study. (5) Isolated AS was less frequent. (6) The unusual finding such as right ventricular hypertrophy on EKG was present due to associated cardiac anomalies. Open-heart surgery is effective and safe, but the efficacy of balloon dilation requires further investigation.

A program of operative angioplasty: endovascular intervention and the vascular surgeon

PURPOSE

Vascular surgeons are ideally suited to select and perform endovascular interventions either as primary therapy or as an adjunct to bypass surgery. Attaining proficiency in endovascular techniques is an important goal in the training of vascular surgeons. We report our initial experience with a program of endovascular intervention performed in the operating room by vascular surgeons.

METHODS

During the previous three years, we performed 109 angioplasty procedures, 60 aortoiliac (55%), 32 femoropopliteal (29%), and 17 popliteal/tibial (16%), using guidewires and angioplasty balloons directed by intraoperative digital subtraction C-arm arteriography with road-mapping capabilities. Indications for angioplasty included disabling claudication in 59 patients (54%), rest pain in 18 (17%), and tissue loss in 32 (29%). Angioplasty was accompanied by stent placement in 39 of 60 aortoiliac procedures (65%) and in two of 32 femoral procedures (6%). In 16 cases (15%), the endovascular procedure was performed in conjunction with a bypass procedure. In selected cases (15, 14%), duplex scanning was the sole diagnostic method used before surgery to identify the lesion, eliminating the need for preoperative arteriographic scans. Segmental pressure measurements, duplex ultrasound scans, and treadmill exercise testing as indicated were performed before and after surgery. The efficacy of the endovascular intervention was assessed at 3-month intervals during the first year and at 6-month intervals thereafter.

RESULTS

A successful results was defined using criteria recommended by the Ad Hoc Subcommittee on Reporting Standards for Endovascular Procedures from the Society for Vascular Surgery/International Society for Cardiovascular Surgery. This included the combination of symptomatic improvement, obtaining an anatomically successful result with < 30% residual lumen stenosis, and elimination of the translesion gradient with an improvement in high thigh-brachial index or ankle-brachial index greater than 0.15. Initial success was achieved in 55 of 60 aortoiliac (92%), 28 of 32 femoropopliteal (88%), and 16 of 17 popliteal/tibial (94%) angioplasty procedures. Clinical follow-up has been achieved in all cases, with continued clinical success rates of 80%, 75%, and 82% for aortoiliac, femoropopliteal, and popliteal/tibial angioplasty procedures, respectively, with a mean follow-up of 15.7 months.

CONCLUSION

These results confirm the value of a program in which C-arm technology was used by vascular surgeons in the performance of angioplasty and stenting procedures in the operating room. This experience in therapeutic endovascular intervention will facilitate the credentialing process for future vascular surgeons.

Detachment of balloon in an infant: a rare complication of balloon pulmonary valvuloplasty

A 3-month-old infant with severe tetralogy of Fallot underwent percutaneous balloon valvuloplasty. After the successful dilatation, the balloon could not be deflated completely and the partial deflated balloon was totally peeled off from the catheter at the junction of inferior vena cava and right common iliac vein when we attempted to move it out. The skin of the balloon was successfully retrieved with a snared guidewire without sequel.

Prolonged infusion of etoposide in patients with advanced non-small cell lung cancer

We assessed the efficacy and toxicity of two etoposide infusional schedules in patients with advanced non-small cell lung cancer (NSCLC). Twenty-six patients were treated with a 21-day infusion every 28 days at a dose of 25-40 mg/m2/d, and six patients with a 7-day infusion every 21 days at a dose of 45-75 mg/m2/d. Sixty-three percent of patients had a Karnofsky status of 80% or better, and only five (15%) patients had prior chemotherapy. Plasma etoposide concentrations were determined in 26 patients. Sixty-nine treatment cycles were administered. Two patients (6.3%; 90% confidence interval, 1.1-18.4%) had partial responses; with response durations of 2 and 7 months, respectively. The median survival was 4 months. Grade 3 or 4 neutropenia occurred in 13 of 69 cycles (19%) and was associated with three toxic deaths. Ten patients required RBC transfusions. Nausea was common, but was associated with vomiting in only 7% of all cycles. The interpatient variability of etoposide concentrations at steady state was significant. We conclude that the antitumor activity of prolonged infusion of etoposide is not superior to standard dose and schedule in advanced NSCLC.

A population based case-control study of agricultural injuries in children

OBJECTIVES

To identify preventable risk factors related to agricultural injuries occurring to children on family farms.

SETTING

A geographically defined central region of Wisconsin, USA with nearly 1800 family dairy farms.

METHODS

A two year, population based incidence study of occupational injuries among farm residents was conducted. For cases, trained staff abstracted information on the nature, severity, and treatment of the injury from the patient's medical record. Staff also administered a telephone questionnaire to cases and controls, usually answered by parents.

RESULTS

There were 60 cases of farm residents younger than 18 years who sought care for acute agriculture related injuries. Farms on which uninjured children lived served as controls (n = 102). Multivariate analyses of 16 different variables revealed three significantly related to injuries to children: hours worked per week (odds ratio (OR) = 1.05; 95% confidence interval (CI) = 1.01 to 1.08); presence of disabled safety device (OR = 2.64; 95% CI = 1.10 to 6.35); and feeding cows by grazing (OR = 0.22; 95% CI = 0.06 to 8.83).

CONCLUSIONS

Interventions designed to reduce the risk of agricultural injuries to farm children should acknowledge the participation of children as productive workers on the farm. Although education has been the standard method for encouraging safe practices in farm work, additional approaches, such as limiting the number of hours a child works, avoiding the disabling of safety devices, and using specific methods of managing cows, should also be adopted to minimize injury risks to farm children.

Phase I and pharmacologic study of 7- and 21-day continuous etoposide infusion in patients with advanced cancer

PURPOSE

This phase I study was undertaken to evaluate the safety and tolerability of prolonged infusional etoposide, and to evaluate its pharmacokinetic/pharmacodynamic profile in patients with advanced cancer.

METHODS

A group of 17 patients received a 7-day infusion of etoposide (schedule A) every 21 days at doses from 30 to 75 mg/m2 per day, and a second group of 37 patients a 21-day infusion (schedule B) every 28 days at doses from 18 to 40 mg/m2 per day. Patients had a median Karnofsky performance status (PS) of 80%, and 34 patients had no prior chemotherapy. Etoposide concentrations at steady state (Css) and other pharmacokinetic parameters (plasma clearance, CLp; area under the curve, AUC) were determined during the first treatment cycle. Correlation coefficients were calculated to measure the relationship between variables.

RESULTS

Myelosuppression was the major toxicity, and was associated with three deaths. The maximum tolerated dose due to neutropenia was 75 mg/m2 per day for schedule A and 40 mg/m2 per day for schedule B. There was significant interpatient pharmacokinetic variability in both infusional schedules. Even though etoposide dose levels did not significantly correlate with plasma levels, the Css was > or = 1 microgram/ml in the majority of the patients. A significant correlation between AUC and neutrophil absolute decrease was noted only in schedule B (r = 0.56, P = 0.003). There were several marginal relationships in schedule B: PS versus Css (r = 0.31, P = 0.058), PS versus AUC (r = -0.38; P = 0.058) and age versus CLp (r = -0.31, P = 0.057).

CONCLUSION

Overall, significant correlations were found for several hematologic variables and etoposide dose levels, but not with the Css values. One major problem with the application of pharmacodynamic models to predict hematologic toxicity in clinical practice is the presence of significant interpatient variability.

A clinical observation of term infants with critical cardiovascular disorders

BACKGROUND

Cardiovascular disorders are known to be the major causes for infants requiring intensive care. The consequences of the treatment given to these infants suffering from congestive heart failure and/or cyanosis need to be evaluated.

METHODS

A total of 210 infants both at term suffering from critical cardiovascular problems were hospitalized in the pediatric and neonatal ICU between July 1990 and December 1993. The etiology, clinical data, emergency procedures and outcomes of infants with or without congestive heart failure or cyanosis were analyzed.

RESULTS

Congenital cardiac defects were the most common cause of critical cardiovascular disorders in infancy. These included ventricular septal defect in 42 (20%), Tetralogy of Fallot in 22 (10.5%), Dtransposition of the great arteries in 20 (9.5%) cases, etc. The most common symptoms and signs observed were congestive heart failure in 162 (77.1%) and cyanosis in 137 (65.2%) cases. In spite of aggressive medical and surgical treatments, the outcomes were still unsatisfactory. The mortality rate was found to be the same in infants with or without congestive heart failure, but was significantly higher in infants with cyanosis than in those without cyanosis, after operation (28.5% vs 5.5%, p < 0.05).

CONCLUSIONS

Infants suffering from critical cardiovascular disorders need urgent medical and surgical treatments in intensive care units. In spite of treatment, the outcomes are still unsatisfactory.

Interactions between leukemia cells and bone marrow stromal cells: stroma-supported growth vs. serum dependence and the roles of TGF-beta and M-CSF

Leukemia cell lines that do not proliferate in the absence of serum grow well when cultured with stromal cells. To study this growth dependence on stroma, we selected the M1 myeloblast clone, since its stroma dependence is reminiscent of that exhibited by hematopoietic stem cells. Conditioned medium form a stromal cell line, prepared under serum-free conditions, contained an activity that induced the proliferation of M1 cells and was therefore designated M1 myeloid activity (MMA). Among the various cytokines tested for MMA-like activity, only transforming growth factor-beta (TGF-beta) and macrophage colony-stimulating factor (M-CSF) were found to affect M1 cell survival, and the two cytokines acted synergistically to induce M1 cell growth. Antibodies to both TGF-beta and M-CSF abolished most, but not all, of the MMA in the medium conditioned by stromal cells, indicating that additional factors contribute to MMA. A subclone of M1 cells, M1/M2, selected in medium conditioned by stroma, was found to respond to stromal stimulation but was unable to proliferate in fetal calf serum (FCS). Neutralization experiments indicated that M1/2 cell growth depended mainly on M-CSF and also partially on TGF-beta. By contrast, the same neutralizing antibodies did not affect the ability of serum to support M1 cell growth. The molecules that promoted leukemia cell growth in serum seemed therefore to differ from those provided by stroma. This model system may offer novel information on the interactions of normal and leukemic hematopoietic cells with their stromal microenvironment.

A hematopoietic organ-specific 49-kD nuclear antigen: predominance in immature normal and tumor granulocytes and detection in hematopoietic precursor cells

A 49-kD protein was specifically detected in hematopoietic organs by Western blotting with a novel mouse monoclonal antibody (B92) raised against stromal cells. The protein was found in the immunizing cells using a sensitive method. However, its detection in the bone marrow by the B92 antibody seemed to stem from the abundance of p49 in immature cells of the myeloid lineage. Study of the bone marrow following in vivo irradiation or 5-fluorouracil (5-FU) treatment, in vitro culture with differentiation-inducing factors and long-term culture, and cell sorting all pointed in the same direction: the protein was found in early myeloid cells and in hematopoietic precursor cells. These results were in accordance with the specific presence of p49 in primary radiation-induced myeloid leukemia and its absence in spontaneous B lymphoma. Immunofluorescent staining using B92 antibody detected a nuclear antigen forming a dotted pattern in early myeloid cells and day 12 colony-forming units-spleen (CFU-S). Nuclear localization of p49 was further demonstrated by subcellular fractionation followed by Western blotting. We thus identified a nuclear protein that within the hematopoietic population is detected in hematopoietic precursor cells, predominates in early myeloid cells, and is reduced following differentiation. These properties imply that p49 might be involved in the regulation of hematopoietic cell growth or differentiation.

Proton magnetic resonance spectroscopy in patients with glial tumors: a multicenter study

The authors represent a cooperative group of 15 institutions that examined the feasibility of using metabolic features observed in vivo with 1H-magnetic resonance (MR) spectroscopy to characterize brain tumors of the glial type. The institutions provided blinded, centralized MR spectroscopy data processing long with independent central review of MR spectroscopy voxel placement, composition and contamination by brain, histopathological typing using current World Health Organization criteria, and clinical data. Proton 1H-MR spectroscopy was performed using a spin-echo technique to obtain spectra from 8-cc voxels in the tumor and when feasible in the contralateral brain. Eighty-six cases were assessable, 41 of which had contralateral brain spectra. Glial tumors had significantly elevated intensities of choline signals, decreased intensities of creatine signals, and decreased intensities of N-acetylaspartate compared to brain. Choline signal intensities were highest in astrocytomas and anaplastic astrocytomas, and creatine signal intensities were lowest in glioblastomas. However, whether expressed relative to brain or as intratumoral ratios, these metabolic characteristics exhibited large variations within each subtype of glial tumor. The resulting overlaps precluded diagnostic accuracy in the distinction of low-and high-grade tumors. Although the extent of contamination of the 1H-MR spectroscopy voxel by brain had a marked effect on metabolite concentrations and ratios, selection of cases with minimal contamination did not reduce these overlaps. Thus, each type and grade of tumor is a metabolically hetero-geneous group. Lactate occurred infrequently and in all grades. Mobile lipids, on the other hand, occurred in 41% of high-grade tumors with higher mean amounts found in glioblastomas. This result, coupled with the recent demonstration that intratumoral mobile lipids correlate with microscopic tumor cell necrosis, leads to the hypothesis that mobile lipids observed in vivo in 1H-MR spectroscopy may correlate independently with prognosis of individual patients.

Sterol regulatory element binding protein binds to a cis element in the promoter of the farnesyl diphosphate synthase gene

Sterol-regulated transcription of the gene for rat farnesyl diphosphate (FPP) synthase (geranyl-diphosphate:isopentenyl-diphosphate geranyltranstransferase, EC 2.5.1.10) is dependent in part on the binding of the ubiquitous transcription factor NF-Y to a 6-bp element within the proximal promoter. Current studies identify a second element in this promoter that is also required for sterol-regulated transcription in vivo. Mutation of three nucleotides (CAC) within this element blocks the 8-fold induction of FPP synthase promoter-reporter genes that normally occurs when the transfected cells are incubated in medium deprived of sterols. Gel mobility-shift assays demonstrate that the transcriptionally active 68-kDa fragment of the sterol regulatory element (SRE-1)-binding protein assays (SREBP-1) binds to an oligonucleotide containing the wild-type sequence but not to an oligonucleotide in which the CAC has been mutated. DNase 1 protection pattern (footprint) analysis indicates that SREBP-1 binds to nucleotides that include the CAC. Both the in vivo and in vitro assays are affected by mutagenesis of nucleotides adjacent to the CAC. Coexpression of SREBP with a wild-type FPP synthase promoter-reporter gene in CV-1 cells results in very high levels of reporter activity that is sterol-independent. In contrast, the reporter activity remained low when the promoter contained a mutation in the CAC trinucleotide. We conclude that sterol-regulated transcription of FPP synthase is controlled in part by the interaction of SREBP with a binding site that we have termed SRE-3. Identification of this element may prove useful in the identification of other genes that are both regulated by SREBP and involved in lipid biosynthesis.

The plasmacytoma growth inhibitor restrictin-P is an antagonist of interleukin 6 and interleukin 11. Identification as a stroma-derived activin A

A stromal protein, designated restrictin-P, that specifically kills plasma-like cells was purified to homogeneity and shown to be identical with activin A. The specificity to plasma-like cells stemmed from the ability of restrictin-P/activin A to competitively antagonize the proliferation-inducing effects of interleukin (IL) 6 and IL-11. Restrictin-P further interfered with the IL-6-induced secretion of acute phase proteins by HepG2 human hepatoma cells and with the IL-6-mediated differentiation of M1 myeloblasts. A competition binding assay indicated that restrictin-P did not interfere with the binding of IL-6 to its receptor on plasma-like cells, suggesting that it may act by intervening in the signal transduction pathway of the growth factor. Indeed, concomitant addition of restrictin-P and IL-6 to cytokine-deprived B9 hybridoma cells was followed by sustained overexpression of junB gene until cell death occurred, while IL-6 alone caused a transient increase only. This altered response to IL-6 stimulation was accompanied by a moderate increase in STAT protein activation. Thus, in this study, we identified the plasmacytoma growth inhibitor, restrictin-P, as being activin A of stromal origin. It is shown that activin A is an antagonist of IL-6-induced functions and that it modifies the IL-6 signaling pattern.

Quelling the red menace: haem capture by bacteria

Haem is an important bacterial nutrient. As a prosthetic group of several proteins, haem functions as a cofactor mediating oxygen transport, energy generation, and mixed-function oxidation. In addition, the iron chelated in the porphyrin ring may serve as an iron substrate for growth. However, because of its propensity for oxidizing cellular constituents, haem is always associated with proteins. Therefore, the uptake and transit of haem across bacterial membranes requires the participation of protein escorts. Bacteria have evolved a diverse array of surface-exposed receptors dedicated to binding haem and haem-proteins. Following this selective recognition at the bacterial cell surface, haem is transported across the outer membrane via a TonB-dependent process. The control of receptor expression appears to be multifactorial, probably involving a number of global regulators. A model integrating this information is presented.

Palliative treatment for tetralogy of Fallot with percutaneous balloon dilatation of right ventricular outflow tract

Percutaneous balloon pulmonary dilatation of the right ventricular tract was performed on 16 children with tetralogy of Fallot for palliative purposes after routine cardiac catheterization. Immediate improvement in aortic saturation from 73.4 +/- 6.8 to 84.0 +/- 4.8% (mean +/- SD = 10.6 +/- 2.7%, p < 0.001) and clinical symptoms were achieved in all 16 cases. The pressures in the right ventricle, pulmonary artery, left ventricle and aorta showed no remarkable changes after percutaneous balloon dilatation. The diameters of the proximal end and at the first branching of the right and left pulmonary arteries, pulmonary arterial index and the diameter of the descending aorta at the diaphragm increased significantly after balloon dilatation (p value 0.0004-0.006). One child suffered from repeated cyanotic spells in spite of the immediate improvement of aortic saturation. She received a left side Blalock-Taussig shunt 2 months after the balloon dilatation. None of the children had a significant complication. Eight had follow-up cardiac catheterization one year later and demonstrated much improvement in the diameters of the proximal end and at the first branching of the right and left pulmonary arteries, pulmonary arterial index and the diameter of the descending aorta at the diaphragm (p value 0.005-0.04). All 8 patients had their cardiac lesions successfully corrected. Percutaneous balloon dilatation is an alternative palliative therapy for children with tetralogy of Fallot.

Fast spin-echo magnetic resonance imaging for radiological assessment of neonatal brachial plexus injury

Neurosurgical management of birth-related brachial plexus palsy involves observing the patient for a period of several months. Operative intervention is usually undertaken at 3 to 6 months of age or more in infants who have shown little or no improvement in affected muscle groups. Ancillary tests such as electromyography and nerve conduction studies are occasionally useful. No radiological study has been consistently helpful in operative planning, except for contrast computerized tomography (CT) myelography, which requires general anesthesia in infants. This is because the infant's small size exceeds the functional resolution of the imaging modalities. This report describes the use of a special sequence of magnetic resonance (MR) imaging entitled "fast spin echo" (FSE-MR). Unlike CT myelography, this technique provides high-speed noninvasive imaging that allows clinicians to evaluate preganglionic nerve root injuries without the use of general anesthesia and lumbar puncture. The utility of this technique is illustrated in three cases, two involving either infraclavicular exploration or a combination of infraclavicular and supraclavicular exposure based on FSE-MR findings. The FSE-MR imaging offers an excellent alternative to contrast CT myelography in evaluation of infants with birth-related brachial plexus injuries.

Triopia: craniofacial malformation with prosencephalic duplication

A case of ocular duplication with complex craniofacial and central nervous system anomalies is described. The anomaly is termed triopia because the child's most overt and distinguishing feature was three eyes: the left orbit contained two globes with independent ocular adnexa; the right orbit contained one normal appearing and functioning globe. Computer assisted medical imaging was used to define, in vivo, the intra- and extracranial soft and hard tissue anomalies: the cerebral hemisphere ipsilateral to the ocular duplication was also duplicated. Possible bases for this anomaly include duplication of primordia for the eye and secondary prosencephalon.

Preliminary study of magnetic resonance imaging characteristics in 8- to 16-year-olds with mania

OBJECTIVE

To examine magnetic resonance imaging (MRI) characteristics in children and adolescents with mania according to DSM-III-R criteria.

METHOD

A convenience sample of consecutively referred 8- to 16-year-old manic (n = 10) and normal (n = 5) subjects were assessed using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present Episode Version, the Children's Global Assessment Scale, and the Family History-Research Diagnostic Criteria. MRI scans were obtained from unsedated subjects using a 1.5 T MR scanner to acquire T1-weighted coronal and sagittal images and T2-weighted axial images. Images were assessed by blind clinical interpretation, ratings of T2-weighted deep white matter hyperintensities and petalia, and computer-assisted volumetric analysis of ventricular and cerebral volumes.

RESULTS

Eight of 10 manic subjects and all 5 controls completed the scans. Scans of 4 manic subjects and 1 control subject showed ventricular or white matter abnormalities by clinical interpretation. Significant findings were positive correlations between increasing age and both right and left ventricular volumes. Two of the 8 manic subjects and no controls had confluent subcortical hyperintensities.

CONCLUSIONS

MRI brain scanning was feasible in 8- to 16-year-olds. Preliminary findings from clinical interpretations and structured ratings suggest structural differences between young manic and normal subjects. Investigations of larger samples are needed to better characterize the differences.

Accuracy of neurologic examination and history in detecting evidence of MRI-diagnosed cerebral infarctions in children with sickle cell hemoglobinopathy

We determined the accuracy of neurologic examination and the history of a previous neurologic event in detecting clinical evidence of a magnetic resonance imaging (MRI)-diagnosed cerebral infarction in 30 children with sickle cell hemoglobinopathy. Each patient had an MRI of the brain, neurologic examination, chart review, and psychometric evaluation. Seventeen children (57%) had MRI evidence of cerebral infarction based on demonstration of parenchymal abnormalities in a vascular distribution. Among the 17 children with MRI evidence of cerebral infarction, only 12 (71%) had an abnormal neurologic examination, and 11 (65%) had a history of a prior neurologic event. In contrast, among the 13 children with normal MRIs, 12 (92%) had normal neurologic examinations, and no child had a previous history of a neurologic event. Multiple, bilateral, heterogeneous cerebral infarctions frequently occur without overt neurologic signs or symptoms in children with sickle cell hemoglobinopathy. Previous studies that relied on a focal neurologic examination or a history of a neurologic event to identify cerebral infarctions in patients with sickle cell hemoglobinopathy most likely underrepresented the true frequency of cerebral infarctions in this population. Future prospective studies of cerebral infarctions in children with sickle cell hemoglobinopathy should include MRIs for identification and classification, rather than neurologic examination or clinical history alone.

MR angiography in pediatric neurological disorders

MR angiography using 3D and 2D time-of-flight techniques were used to evaluate pediatric neurological disorders. MRA (arteriography) and MRV (venography) were abnormal in 63 and 45 cases, respectively. Conventional cerebral angiography was performed in 30 cases. These techniques were compared with MRI and conventional angiography. In addition, the value of MR angiography for surgical planning was subjectively evaluated. Our results showed that intracranial vessels were invariably better shown on MR angiography than on MRI. MRA and MRV were most useful in evaluating vascular distortions related to congenital brain malformations and intracranial tumors. MRA was valuable in detecting arterial narrowing but overestimated the degree of stenosis compared with conventional angiography. MRV was the technique of choice for evaluation of dural sinus and cerebral venous thrombosis and compression. MRA played little to no role in preoperative planning of vascular malformations and aneurysms. It did not appear to be accurate in assessing tumor vascularity or lesions in small arteries and arteritis.

The significance of calf muscle pump function in venous ulceration

PURPOSE

Patients with clinically evident chronic venous insufficiency were evaluated to relate the degree of insufficiency and calf muscle pump dysfunction to venous ulceration.

METHODS

Sixty-nine limbs in 55 patients with chronic venous insufficiency by Society for Vascular Surgery/International Society for Cardiovascular Surgery Classification were compared in three groups: classes 1 and 2 with no history of ulceration (19 limbs); class 3 with healed ulceration (20 limbs); and class 3 with active ulcers (30 limbs). Air plethysmography measurements of outflow fraction, venous volume, venous filling time, venous filling index, ejection fraction, ejection volume, residual volume fraction, and residual volume were made. In 62 of the 69 limbs, color-flow duplex ultrasonography was used to determine the pattern of reflux.

RESULTS

The outflow fraction was normal in 84%, 75%, and 77% of nonulcerated, healed, and ulcerated limbs. The venous filling index was abnormal in most limbs (nonulcerated 95%, healed 90%, ulcerated 98%) but not significantly different among groups. Differences in calf muscle pump function were significant. Ulcerated limbs had significantly poorer ejection fractions (p = 0.0002) and greater residual volume fractions (p = 0.0006) than nonulcerated or healed limbs. By ultrasonography, deep and superficial vein incompetence was present in most limbs and was not statistically different among groups. Although venous insufficiency was not measurably different among groups, limbs with active venous ulcers had significantly poorer calf muscle pump function than those with healed ulcers or with no history of ulceration.

CONCLUSION

Venous insufficiency is necessary but not sufficient to cause ulceration, and a deficiency of the calf muscle pump is significant to the severity of venous ulceration.

A comparison of cylindrical and Inoue balloon techniques for mitral valvotomy in patients in the United Kingdom

OBJECTIVES

To compare the use of cylindrical balloons and the Inoue balloon for percutaneous mitral valvotomy in patients in the United Kingdom.

DESIGN

Comparison of the haemodynamic results, complications, and symptomatic outcome of balloon dilatation for mitral stenosis in consecutive patients treated by cylindrical balloons and a second consecutive series of patients treated by the Inoue balloon.

SETTING

A tertiary cardiac referral centre in Scotland.

PATIENTS

70 patients (mean age 60.6 years) treated by the single or double cylindrical balloon technique and 70 patients (mean age 58.9 years) treated with the Inoue balloon method.

MAIN OUTCOME MEASURES

Success in obtaining dilatation at the mitral orifice, procedure and screening times, increase in valve area, complications, and early symptomatic outcome.

RESULTS

Dilatation of the mitral valve was obtained in 91% of patients when cylindrical balloons were used and in 99% of patients treated with the Inoue balloon. Use of the Inoue balloon gave significantly shorter procedure and screening times. Technical problems in obtaining and maintaining the position at the mitral orifice were more common with cylindrical balloons. Improvements in valve area and symptoms were not significantly different with use of the two types of balloon. The Inoue balloon avoided cardiac tamponade and the creation of larger atrial septal defects, but had a higher incidence of increase in mitral reflux.

CONCLUSIONS

In these elderly patients, the Inoue balloon method was safer and faster for percutaneous mitral valvotomy, with a higher success rate for dilatation within the valve orifice. Haemodynamic and symptomatic improvement was similar with the two techniques.

Low ignition propensity cigarettes: smoke analysis for carcinogens and testing for mutagenic activity of the smoke particulate matter

In 1990, more than 20% of the almost 5200 deaths from fires in the United States occurred in fires from cigarettes. This fact led to the investigation of cigarettes with low ignition propensity. 32 experimental cigarettes differing in tobacco, cigarette circumference and in cigarette paper were tested for ignition propensity. This communication reports the results of comparative analyses of smoke from two low-propensity experimental cigarettes, A and B, which differed only in the porosity and treatment of the paper, and of the smoke from a reference cigarette C and from two leading US commercial cigarettes D and E. Model cigarette A delivered higher smoke yields of total particulate matter (TPM), nicotine, CO and benzo[a]pyrene than the other four cigarettes, but had lower smoke yields of the carcinogenic, volatile, and tobacco-specific N-nitrosamines than cigarettes C, D and E. The TPM of cigarette A was less active as a frameshift mutagen in tests with Salmonella strain TA98 than was the TPM of cigarettes C, D and E. TPM of cigarette A was also less active as a frameshift mutagen in tester strain TA1538 than was the TPM of reference cigarette C. However, when the mutagenic potencies of the particulate matters were compared on a cigarette-to-cigarette basis, there were no significant differences between the TPM of the individual cigarettes. Replacing the conventional cigarette filter with a perforated filter may significantly reduce the smoke yield of cigarette A. If this can be achieved without changing the ignition propensity, detailed chemical-analytical analyses and in vitro and in vivo assays for toxicity, ciliatoxicity, mutagenic activity and carcinogenicity need to be obtained for the smoke of such a prototype cigarette.

Isolation and characterization of the haemin-binding proteins from Neisseria meningitidis

The mechanism of haem-iron acquisition in Neisseria meningitidis is poorly understood. Using haemin-agarose in a batch affinity chromatography method, two haemin-binding proteins of 97 and 50 kDa were isolated from total membranes derived from Neisseria meningitidis B16B6 grown under iron-deficient but not under iron-replete conditions. No binding proteins were affinity-purified when total membranes underwent limited proteolysis with trypsin, suggesting a haem-protein interaction. When biotinylated human haemoglobin was used as the affinity ligand, proteins of identical molecular mass were isolated. Detection of haemin-binding proteins in a whole cell binding assay demonstrated a surface-exposed location. Competitive binding studies indicated that this haem-protein interaction was specific, because only haemin or human haemoglobin, but not cytochrome c111, protoporphyrin IX, iron-loaded human lactoferrin, iron-loaded human transferrin or Fe(NO3)3, could abrogate binding. The presence of similar haemin-binding proteins in a limited survey of clinical meningococcal strains indicated that the expression of the haemin-binding proteins is not serogroup-specific.

Intra-carotid thrombolytic therapy in acute ischemic stroke of carotid arterial territory

Intra-carotid urokinase (UK) infusion in 20 patients with acute internal carotid artery (ICA) territorial ischemic stroke achieved immediate recanalization in 45% and the clinical outcome in patients with recanalization was superior to that of patients without recanalization. The procedure was most effective in patients with smaller arterial occlusions: 7 of 10 patients with MCA branch occlusions (M2 to M4) achieved recanalization compared to only 2 of 10 with distal ICA or M1 occlusions, which should be an important issue for the critical evaluation of the efficacy of thrombolytic therapy (TT). Hemorrhagic transformation was observed in 9 patients on CT scan; petechial hemorrhage in 5 and intraparenchymal hematoma formation in 4. Among 4 patients with hematoma formation, clinical deterioration was seen in 3 cases and the angiography at the immediate end of the UK infusion showed recanalization in only one patient. The average dose of UK in patients with parenchymal hematoma formation was higher than that of patients without hemorrhagic transformation (123.3 x 10(4) units vs 101 x 10(4) units). The administration of a large dose of UK, probably more than 100 x 10(4) units, and the absence of immediate recanalization seemed to increase the risk of parenchymal hematoma formation. Despite the effort of investigators, the in-hospital time delay for the TT was significant which was mainly related to the time consuming preparation for angiography especially during night. A more effective system for the earlier intervention of acute ischemic stroke needs to be developed.

Somatic embryogenesis and plant regeneration in Quercus acutissima

Immature embryos of Quercus acutissima were collected weekly beginning 5 weeks post-fertilization and cultured on modified MS(Murashige and Skoog) medium containing 1,000 mg/l glutamine and 5 mM proline with different combinations of IBA(0.5-10.0 mg/l) and BA(0 or 1.0 mg/l) in light. The highest percentage of embryogenic cultures occurred on the medium containing 0.5 mg/l IBA or 1.0 mg/l BA and 0.5 mg/l IBA. Four weeks after initiation, the embryogenic cultures were transferred to MS medium without plant growth regulators and cultured for 4 weeks. The somatic embryos were then transferred to germination medium. The best germination results were achieved from WPM(Woody Plant Medium) containing 0.1 mg/l BA. Plantlets from somatic embryos were incubated on WPM supplemented with 0.2 mg/l BA for 4 weeks and plantlets with well developed shoots and roots were transplanted to perlite and peat moss(1∶1, v/v) mixtures and placed in a culture room. After being hardened off for 8 weeks, they were transferred outdoors where they grew.

Acquisition of heme iron by Neisseria meningitidis does not involve meningococcal transferrin-binding proteins

Similarities in size between hemin-binding protein 1 (HmBP1) and transferrin-binding protein 1 (TBP1) of Neisseria meningitidis suggest that these proteins are functionally homologous. However, a meningococcal mutant lacking the transferrin-binding proteins retained the capacity to acquire iron from heme and hemoglobin. In immunoblots, hyperimmune polyclonal antiserum against TBP1 did not react with HmBP1.

Binding kinetics of ATP gamma S35 on cultured primary tracheal surface epithelial cells

Extracellular ATP can stimulate mucin release from primary hamster tracheal surface epithelial (HTSE) cells via a P2 purinoceptor-mediated mechanism, based on agonist potency studies of mucin release (Br. J. Pharmacol. 1991; 103:1053-1056). In the present study, we examined the kinetics of ATP binding to the surface of intact HTSE cells at 4 degrees C using ATP gamma S35 as a radioligand. We found that ATP gamma S35 bound to HTSE cells in a saturable, reversible manner, reaching an equilibrium at about 30 min. Scatchard analysis of equilibrium binding suggested the presence of two binding sites with Kd values of 0.47 and 9.4 microM. Competitive binding experiments, based on the ability of nucleotides and ATP analogs to block ATP gamma S35 revealed a rank order of ATP > ADP > alpha,beta-methylene ATP > 2-methylthio ATP > or = beta, gamma-methylene ATP. Neither AMP nor adenosine could inhibit the ATP gamma S35 binding. A comparison between the ability of nucleotides to compete with ATP gamma S35 binding and their ability to induce mucin release revealed a rather poor correlation (r2 = 0.67) with all of the above nucleotides but a good correlation (r2 = 0.96) without 2-methylthio ATP, indicating the presence of heterogenous ATP binding sites on the HTSE cell surface. UTP, a pyrimidine nucleotide, which is almost equipotent with ATP in its ability to stimulate mucin release, was much less potent than ATP in its ability to displace the ATP gamma S35 binding in these HTSE cells.

Glycolipid composition of human cataractous lenses. Characterization of Lewisx glycolipids

We have studied the glycolipid composition of human cataractous lenses. Neutral and acidic lipid fractions were isolated by column chromatographies on DEAE-Sephadex and Iatrobeads. The neutral glycolipid fraction and acidic glycolipid fraction contained 0.6-0.9 micrograms of lipid-bound glucose (Glc) per mg of protein and 0.8-1.3 micrograms of lipid-bound sialic acid (NeuAc) per mg of protein, respectively. The neutral glycolipid fraction was found to contain LacCer (39.0% of total neutral glycolipids), Gb3 (16.2%), Gb4 (1.1%), nLc4 (5.0%), X (29.0%), and Y (9.2%). The acidic lipid fraction was found to contain mainly GM3 (33.1% of the total ganglioside fraction), GM1 (8.3%), LM1 (7.3%), GD1a (16.0%), and G (30.1%). The structures of neutral glycolipids X and Y and ganglioside G were elucidated by high performance thin-layer chromatography overlay method of glycolipids, gas-liquid chromatography, proton NMR spectrometry, and liquid secondary ion mass spectrometry as follows: 1) X, Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer, III3FucnLc4 (Lex); 2) Y, Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4(Fuc alpha 1- 3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer, V3FucIII3FucnLc6; and 3) G, NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3 Gal-beta 1-4Glc beta 1-1'Cer, IV3NeuAcIII3FucnLc4 (sialosyl-Le(x)). A minor neutral glycolipid Z was isolated and tentatively characterized as GlcNAc beta 1-3?Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer (GlcNAc-Le(x)), suggesting that it may be the precursor of glycolipid Y. The major long-chain base of these human cataract glycolipids was C18:0 sphingosine (sphinganine). The major fatty acids were C16:0, C24:1 and C24:0, and monounsaturated fatty acids accounted for 40-55% of the total fatty acids.

Low incidence of hypercalcaemia in tuberculosis in Malaysia

In this study we examined the incidence of hypercalcaemia among patients with tuberculosis in Malaysia. Serum calcium concentration and other calcium metabolism parameters were studied in 43 newly diagnosed tuberculous patients from the Kuala Lumpur General Hospital and the National Tuberculosis Centre. Forty-four patients admitted to the medical wards of the General Hospital, Kuala Lumpur were recruited as controls. The incidence of hypercalcaemia was found to be only 1/43 (2.3%). There was no significant difference between the mean serum calcium and other calcium metabolism parameters between the patients and the controls. Despite earlier reported incidences of 30-50%, this study showed that hypercalcaemia in tuberculosis is uncommon in Malaysia.

Diagnosis of tuberculous meningitis by detection of immunoglobulin G antibodies to purified protein derivative and lipoarabinomannan antigen in cerebrospinal fluid

Enzyme-linked immunosorbent assay of immunoglobulin G (IgG) activity in cerebrospinal fluid (CSF) and sera was conducted prospectively in 27 patients with tuberculous meningitis (TBM) by using purified protein derivative (PPD) and lipoarabinomannan (LAM) antigens, from January 1989 to August 1990. 29 patients with aseptic meningitis and 49 patients with non-inflammatory neurological illnesses served as controls. All patients had a computed tomography (CT) scan of the head before a lumbar puncture. The IgG antibodies to the antigens were significantly elevated in TBM, and the reactivity was more frequently positive in the CSF than in the sera, suggesting a local synthesis of IgG in the central nervous system (CNS). The sensitivity and the specificity for the diagnosis of TBM were 59.2% and 93.9% for PPD antigen, and 85.2% and 95.9% for LAM antigen, respectively. Assay of IgG reactivity to LAM antigen was clinically very useful for the early diagnosis of TBM and was superior to PPD for detecting the serological evidence of TBM.

Spiral CT of the temporal bone in unsedated pediatric patients

PURPOSE

To determine the feasibility of performing rapid, high-resolution, low-radiation-dose spiral CT scans of the temporal bone in unsedated pediatric patients.

METHODS

Axial spiral CT examinations with an effective section thickness of 1.25 mm were performed in 41 infants and children. Multiplanar reconstructions were generated using 360 degrees and 180 degrees linear interpolation algorithms. Three-dimensional reconstructions of the middle ear were also performed.

RESULTS

Complete axial spiral scans were performed without sedation in all patients. Three hundred sixty-degree linear interpolation images had comparable resolution to conventional CT; 180 degrees linear interpolation images with an effective section thickness of 1.0 mm at 0.2-mm intervals showed good detail of middle and inner ear anatomy, and multiplanar reconstructions from this algorithm were comparable to direct scans. Three-dimensional reconstructions clearly displayed the oval window, malleus, and incus.

CONCLUSION

Spiral CT is a clinically feasible method for rapidly evaluating the temporal bone in pediatric patients, eliminating the need for sedation. The images obtained from this technique are comparable to conventional CT. High-quality multiplanar reconstructions can be generated from the spiral data set, providing an alternative to direct scans in multiple planes. Additionally, three-dimensional images of internal temporal bone anatomy can be generated from the spiral data.

Smith-Lemli-Opitz syndrome type II: report of a case with additional radiographic findings

A phenotypically female infant with 46-XY chromosomes was found to have Smith-Lemli-Opitz syndrome, type II a rare congenital malformation syndrome with many features of the more common classic Smith-Lemli-Opitz syndrome. The patient's skeletal survey revealed characteristic and previously undescribed skeletal anomalies which are reported. In addition a lipoma of the pituitary gland was found on magnetic resonance imaging. This lesion is particularly interesting given the hypothesized steroid abnormality in Smith-Lemli-Opitz, type II syndrome, the sexual ambiguity of males with this syndrome and the similarity of this syndrome to the Pallister-Hall syndrome which characteristically has a hamartoblastoma of the hypothalamus.

Tuberculous fasciitis and tenosynovitis. An unusual presentation of miliary tuberculosis

A case of miliary tuberculosis presenting initially as pyogenic fasciitis and tenosynovitis is described. The unusual presenting clinical features suggestive of a noninfectious inflammatory condition resulted in delayed diagnosis. Tuberculous fasciitis and tenosynovitis were diagnosed by the presence of acid-fast bacilli in histopathologic sections and confirmed by the growth of Mycobacterium tuberculosis from cultures of tissue specimens.

Identification of an outer-membrane haemoglobin-binding protein in Neisseria meningitidis

Although Neisseria meningitidis can use haemoglobin as an iron source in vitro, the mechanism of haemoglobin-iron uptake is unknown. Using a biotinylated human haemoglobin probe in a solid-phase dot-binding assay, haemoglobin-binding activity was detected in total membranes derived from meningococci grown under iron-limited but not iron-sufficient conditions. In competition binding experiments, bovine and human haemoglobin could abrogate binding. In contrast, no binding inhibition was seen with ferric nitrate, protoporphyrin IX, and iron-loaded human transferrin. The ability of both haemin and catalase, a nonhaemoglobin haem-containing compound, to inhibit binding competitively suggested that the ligand recognized by the binding protein is the haem moiety. Scatchard plot analysis revealed a heterogeneous receptor population. Limited proteolysis with proteinase K abolished binding activity, suggesting a haemoglobin-protein interaction. Detection of activity in a whole-cell binding assay demonstrated that this haemin-binding protein was surface exposed. In a limited survey of meningococcal strains, the presence of haemoglobin-binding activity in all isolates indicated that expression of this binding protein is not serogroup specific.

Infrapopliteal arterial injury: prompt revascularization affords optimal limb salvage

Sixty-nine limbs with infrapopliteal arterial injuries were evaluated in 68 patients. Thirty-five (50%) cases were complicated by acute limb-threatening ischemia. Management consisted of revascularization (26 limbs), ligation (15 limbs), fasciotomy only (2 limbs), observation (18 limbs), and primary amputation (8 limbs). Penetrating injuries (n = 35) had a 33% incidence of ischemia and a reduced frequency of associated injury. One delayed amputation (3%) was required. In contrast, blunt injuries (n = 34) had a 68% incidence of ischemia and a greater frequency of associated injury. There were 20 amputations in the blunt group, including eight primary amputations performed in limbs with profound ischemia, complex open fractures, severe soft-tissue damage, and neural injury. Observation or ligation of single arterial injuries resulted in no early amputations. Associated local injuries in both groups included fracture or ligamentous disruption (64%), severe soft-tissue damage (32%), and nerve dysfunction (36%). In both groups, 15 of 35 ischemic limbs were salvaged by prompt revascularization (11 penetrating and four blunt injuries). Aggressive revascularization with autogenous repair or bypass is recommended for management of penetrating trauma. Though a good outcome will be achieved in some patients with combined blunt trauma and infrapopliteal arterial injury, the probability of delayed amputation and prolonged disability must be consciously integrated into the decision to pursue limb salvage. The prognosis for blunt injury complicated by arterial ischemia is poor; thus the severity of associated local and remote injuries will affect the results of revascularization program.

Prolonged ictal amnesia with transient focal abnormalities on magnetic resonance imaging

A previously healthy woman had a prolonged amnestic state caused by complex partial status epilepticus with bilateral mesiotemporal lobe involvement confirmed by EEG with nasopharyngeal electrodes. A magnetic resonance imaging (MRI) scan obtained shortly after recovery from the amnesia showed reversible focal abnormalities consisting of increased signal intensity on T2-weighted scan in the mesiotemporal lobe.

Isolation of haemin-binding proteins of Neisseria gonorrhoeae

Although Neisseria gonorrhoeae can use haem as the sole exogenous iron source for growth in vitro, the mechanism of haem-iron uptake in the gonococcus is unknown. Two haemin-binding proteins (HmBPs) of 97 and 44 Kda were isolated by batch ligand affinity-chromatography from whole cells or total membranes of gonococci grown under iron-limited conditions but not from those grown under iron-sufficient conditions. Competition binding experiments indicated that the haemin-protein interaction was specific; only haemin or haem-containing proteins, such as human haemoglobin or equine cytochrome c111, but not protoporphyrin IX, iron loaded human transferrin or lactoferrin, could abrogate binding. Identical HmBPs were isolated from three other clinical gonococcal strains, suggesting that these may be interstrain structural and functional homogeneity amongst these polypeptides.