Spinocerebellar ataxia in Singapore: predictive features of a positive DNA test?

Significant differences in frequency of the different spinocerebellar ataxia (SCA) subtypes have been described to occur in different populations. A 'blunderbuss' diagnostic DNA testing approach would entail unnecessary healthcare cost. In this study, we determine the prevalence of SCA subtypes and predictive features of a positive DNA test in consecutive clinically diagnosed SCA cases in Singapore. Twenty-one consecutive patients from 14 families were evaluated over a 3-year period. Thirteen patients (61.9%) from 6 families had a positive DNA test. Eleven of these (all ethnic Chinese) had SCA 3 (abnormal CAG size ranged from 61 to 71), and 2 ethnic Malays had SCA 2 (abnormal CAG size of 39). Clinical features which were highly predictive of a positive DNA SCA test in our population included presence of a positive family history, chorea and dystonia, muscle and tongue fasciculations, gaze-evoked nystagmus, and hypertonia. Our study draws attention to the observation that knowledge of relatively specific features of the most common SCA subtype in a local population can greatly enhance the practical accuracy of the choice of which SCA DNA test to order.

Dynamic helical computed tomography scan accurately detects hemorrhage in patients with pelvic fracture

BACKGROUND

The purpose of this study was to evaluate the use of dynamic helical computed tomography (CT) scan for screening patients with pelvic fractures and hemorrhage requiring angiographic embolization for control of bleeding.

METHODS

Patients admitted to the trauma service with pelvic fractures were identified from the trauma registry. Data retrieval included demographics, hemodynamic instability, Injury Severity Score, blood transfusion requirement, length of stay, and mortality. CT scans obtained during the initial evaluation were reviewed for the presence of contrast extravasation and correlated with angiographic findings. Data are reported as mean +/- SEM, with P<.05 considered significant.

RESULTS

Seven thousand seven hundred eighty-one patients were admitted from June 1994 to May 1999. A pelvic fracture was diagnosed in 660 (8.5%). Two hundred ninety (44.0%) dynamic helical CT scans were performed, of which 13 (4.5%) identified contrast extravasation. Nine (69%) were hemodynamically unstable and had pelvic arteriography performed. Arterial bleeding was confirmed in all and controlled by embolization. Patients with contrast extravasation had significantly greater Injury Severity Score, blood transfusion requirement and length of stay. Sensitivity, specificity, and accuracy of CT scan for identifying patients requiring embolization were 90.0%, 98.6%, and 98.3%, respectively.

CONCLUSIONS

Early use of dynamic helical CT scanning in the multiply injured patient with a pelvic fracture accurately identifies the need for emergent angiographic embolization.

The unusual mammographic appearance of breasts augmented by autologous fat injection

We report the case of a woman presenting to our centre with two breast lumps, 12 months after undergoing breast augmentation with autologous fat injection. Mammography showed a very unusual appearance, with most of the breast parenchyma displaced anteriorly by a large amount of fatty tissue. This was associated with extensive bizarre microcalcification, highlighting the difficulty in mammographic evaluation of this rare type of breast augmentation.

Nipah viral encephalitis or Japanese encephalitis? MR findings in a new zoonotic disease

BACKGROUND AND PURPOSE

An epidemic of suspected Japanese encephalitis occurred in Malaysia in 1998-1999 among pig farmers. In neighboring Singapore, an outbreak occurred among pig slaughterhouse workers. It was subsequently established that the causative agent in the outbreak was not the Japanese encephalitis virus but a previously unknown Hendra-like paramyxovirus named Nipah virus.

METHODS

The brain MR images of eight patients with Nipah virus infection were reviewed. All patients tested negative for acute Japanese encephalitis virus. Seven patients had contrast-enhanced studies and six had diffusion-weighted examinations.

RESULTS

All patients had multiple small bilateral foci of T2 prolongation within the subcortical and deep white matter. The periventricular region and corpus callosum were also involved. In addition to white matter disease, five patients had cortical lesions, three had brain stem involvement, and a single thalamic lesion was detected in one patient. All lesions were less than 1 cm in maximum diameter. In five patients, diffusion-weighted images showed increased signal. Four patients had leptomeningeal enhancement and four had enhancement of parenchymal lesions.

CONCLUSION

The brain MR findings in patients infected with the newly discovered Nipah paramyxovirus are different from those of patients with Japanese encephalitis. In a zoonotic epidemic, this striking difference in the appearance and distribution of lesions is useful in differentiating these diseases. Diffusion-weighted imaging was advantageous in increasing lesion conspicuity.

Outbreak of Nipah-virus infection among abattoir workers in Singapore

BACKGROUND

In March 1999, an outbreak of encephalitis and pneumonia occurred in workers at an abattoir in Singapore. We describe the clinical presentation and the results of investigations in these patients.

METHODS

Clinical and laboratory data were collected by systemic review of the case records. Serum and cerebrospinal fluid (CSF) samples were tested for IgM antibodies to Nipah virus with an IgM capture ELISA. Reverse-transcriptase PCR was done on the CSF and tissue samples from one patient who died.

FINDINGS

Eleven patients were confirmed to have acute Nipah-virus infection based on raised IgM in serum. Nipah virus was identified by reverse transcriptase PCR in the CSF and tissue of the patient who died. The patients were all men, with a median age of 44 years. The commonest presenting symptoms were fever, headache, and drowsiness. Eight patients presented with signs of encephalitis (decreased level of consciousness or focal neurological signs). Three patients presented with atypical pneumonia, but one later developed hallucinations and had evidence of encephalitis on CSF examination. Abnormal laboratory findings included a low lymphocyte count (nine patients), low platelet count, low serum sodium, and high aspartate aminostransferase concentration (each observed in five patients). The CSF protein was high in eight patients and white-blood-cell count was high in seven. Chest radiography showed mild interstitial shadowing in eight patients. Magnetic resonance imaging (MRI) showed focal areas of increased signal intensity in the cortical white marker in all eight patients who were scanned. The nine patients with encephalitis received empirical treatment with intravenous aciclovir and eight survived.

INTERPRETATION

Infection with Nipah virus caused an encephalitis illness with characteristic focal areas of increased intensity seen on MRI. Lung involvement was also common, and the disease may present as an atypical pneumonia.

Proliferation and collagen synthesis of human anterior cruciate ligament cells in vitro: effects of ascorbate-2-phosphate, dexamethasone and oxygen tension

Clinical and experimental studies demonstrate that injured anterior cruciate ligaments (ACL) do not usually heal and that autografts used to repair the ACL rapidly weaken in the early period and take a long time to regain strength. The aim of this study was to develop an in vitro culture system in which environmental and biochemical factors influencing the proliferation and matrix synthesis of cells derived from human anterior cruciate ligaments can be studied. Primary cultures of human ACL cells were obtained by outgrowth from explants of normal ACL obtained at knee replacement for osteoarthritis in Dulbecco's minimum essential medium (DMEM). The effects of the additives 100 microm L-ascorbic acid-2-phosphate (Asc-2-P) and 10 n m dexamethasone (dex) on proliferation and collagen synthesis were assessed after 4, 8 and 12 days in culture. Ligament cells were grown at 0, 5, 10 and 21%p O(2)in the presence of 100 microm asc-2-P and 10 n m dex. DNA content was assessed using the Hoechst dye method and collagen synthesis by the incorporation of 5 mCi/ml [(3)H]proline after 3, 6 and 12 days in culture. At 21%p O(2), the presence of asc-2-P and dex induced significantly greater (P< 0.01, ANOVA) cell proliferation than with either additives alone. Greatest percentage collagen to total protein synthesis was observed when cells were grown in the presence of asc-2-P only. Least proliferation and percentage collagen to total protein synthesis was seen when both additives were omitted. Greatest cell proliferation was seen when cells were grown in 10%p O(2)and 5%p O(2)was associated with increased collagen synthesis. These results suggest that it is possible to study the effects of environmental and biochemical factors on human ACL healing in vitro. Our data suggest oxygen can influence certain biosynthetic activities of ACL cells. Low oxygen tensions lead to an increase in collagen production by ACL cells. However early responses to injury require extensive cell proliferation which may be activated at higher p O(2). Variation of p O(2)in ligaments during healing may therefore be an important modulator of successful repair.

Effect of a 915-MHz simulated mobile phone signal on cognitive function in man

PURPOSE

To examine whether a simulated mobile telephone transmission at 915 MHz has an effect on cognitive function in man.

MATERIALS AND METHODS

Thirty-six subjects in two groups were each given two training sessions and then three test sessions in a randomized three-way cross-over design. About 1 W mean power at 915 MHz from a quarter-wave antenna mounted on a physical copy of an analogue phone, as a sine wave, or modulated at 217 Hz with 12.5% duty cycle, or no power, was applied to the left squamous temple region of the subjects while they undertook a series of cognitive function tests lasting approximately 25-30 min. The second group was investigated for sleep, consumption of alcohol and beverages, and any other substances that might affect performance.

RESULTS

In both groups, the only test affected was the choice reaction time and this showed as an increase in speed (a decrease in reaction time). There were no changes in word, number or picture recall, or in spatial memory. While an effect of visit-order was evident suggesting a learning effect of repeat tests, the design of the study allowed for this. Additionally, there was no systematic error introduced as a result of consumption of substances or sleep time.

CONCLUSIONS

There was evidence of an increase in responsiveness, strongly in the analogue and less in the digital simulation, in choice reaction time. This could be associated with an effect on the angular gyrus that acts as an interface between the visual and speech centres and which lies directly under and on the same side as the antenna. Such an effect could be consistent with mild localized heating, or possibly a non-thermal response, which is nevertheless power-dependent.

Effect of taurine supplementation on the lipid peroxide formation and the activities of glutathione-related enzymes in the liver and islet of type I and II diabetic model mice

Effects of taurine supplementation on lipid peroxide formation and the activities of glutathione (GSH) dependent enzymes in diabetic model mice were investigated. Type I diabetes mellitus was induced by injecting alloxan to ICR mice while type II diabetes mellitus was produced by high calorie diet feeding to genetically hyperglycemic KK mice. Taurine was given in drinking water at the level of 5% (w/v) for seven days. The malondialdehyde (MDA) levels of liver and the islets of type I diabetes were significantly increased compared to the control group but the levels were significantly decreased by taurine supplementation. In the type II diabetic model, the concentrations of MDA were not changed by taurine treatment. The activity of hepatic and islet GSH-peroxidase (GPX) was increased in the type I diabetic group, but in type II animals it was decreased. Hepatic GPX activity of both type I and II diabetics was not altered by taurine supplementation but was increased in the islets of the type II animals. No effect on the activity of GSH S-transferase (GST) was observed in both types of diabetes (I and II) following taurine supplementation. These results suggest that taurine supplementation protects type I diabetic mice from lipid peroxide formation.

A case of t(8;14) with total and partial trisomy 3 in Waldenstrom macroglobulinemia

A case of Waldenstrom macroglobulinemia with Burkitt-type t(8;14)(q24.1;q32) and total and partial trisomy 3 is reported. This is an unusual combination of chromosomal abnormalities in Waldenstrom macroglobulinemia.

Adult-onset Still's disease in an oriental population: manifestations, course and outcome in 16 patients

This retrospective descriptive study aims to characterise and compare the clinical manifestations, course and outcome of 16 Oriental patients with adult-onset Still's disease diagnosed in the last 4 years with published data based on Western populations and another Oriental (Japanese) series. Like the Japanese, we found a female preponderance, an older age at onset, and fewer patients with abdominal pain, myalgia, sore throat and serositis compared to the Western series. A longer delay in diagnosis occurred in patients lacking either arthritis or rash at presentation. Most patients had mild hyponatraemia and 2 patients had overt syndrome of inappropriate anti-diuretic hormone secretion. All patients showed a dissociation of elevated aldolase with normal to low creatine kinase levels. Over 50% relapsed within a year from diagnosis and needed slow-acting anti-rheumatic drugs as steroid-sparing agents. Two were given intravenous pulse cyclophosphamide therapy for progressive pneumonitis. Outcome was generally good with minimal functional impairment and no mortality.

The effect of early versus late fasciotomy in the management of extremity trauma

BACKGROUND

Recent reports have demonstrated an increase in the number of complications associated with delayed timing of fasciotomy for trauma. This study examines the effectiveness of early (less than 12 hours) versus late (more than 12 hours) fasciotomy in the injured extremity.

METHODS

This is a retrospective review of 88 patients undergoing fasciotomy for extremity trauma admitted to the University of Cincinnati from January 1990 through December 1995. Records were reviewed for demographics, compartment pressures, time and type of fasciotomy, complications, limb salvage, and mortality. Statistical analysis was determined with chi-squared, multivariant regression analysis, and Student's t test with significance at p less than 0.05.

RESULTS

Sixty-one (69%) patients had fasciotomy performed before 12 hours and twenty-seven (31%) after 12 hours. Although the rates of infection differed significantly between the two groups (7.3% for early versus 28% for late), the rates of limb salvage and neurologic sequelae were similar. Age, mechanism, shock, associated injuries, and time to fasciotomy were not predictive of complications.

CONCLUSIONS

Fasciotomy for trauma is most efficacious when performed early. However, when performed late, it results in similar rates of limb salvage as compared with early fasciotomy but at the increased risk of infection. These results support aggressive use of fasciotomy in extremity trauma regardless of time of diagnosis.

Calcineurin is required for virulence of Cryptococcus neoformans

Cyclosporin A (CsA) and FK506 are antimicrobial, immunosuppressive natural products that inhibit signal transduction. In T cells and Saccharomyces cerevisiae, CsA and FK506 bind to the immunophilins cyclophilin A and FKBP12 and the resulting complexes inhibit the Ca2+-regulated protein phosphatase calcineurin. We find that growth of the opportunistic fungal pathogen Cryptococcus neoformans is sensitive to CsA and FK506 at 37 degrees C but not at 24 degrees C, suggesting that CsA and FK506 inhibit a protein required for C. neoformans growth at elevated temperature. Genetic evidence supports a model in which immunophilin-drug complexes inhibit calcineurin to prevent growth at 37 degrees C. The gene encoding the C. neoformans calcineurin A catalytic subunit was cloned and disrupted by homologous recombination. Calcineurin mutant strains are viable but do not survive in vitro conditions that mimic the host environment (elevated temperature, 5% CO2 or alkaline pH) and are no longer pathogenic in an animal model of cryptococcal meningitis. Introduction of the wild-type calcineurin A gene complemented these growth defects and restored virulence. Our findings demonstrate that calcineurin is required for C. neoformans virulence and may define signal transduction elements required for fungal pathogenesis that could be targets for therapeutic intervention.

Mutations that perturb cyclophilin A ligand binding pocket confer cyclosporin A resistance in Saccharomyces cerevisiae

In complex with the peptidyl-prolyl isomerase cyclophilin A, the immunosuppressive antifungal drug cyclosporin A (CsA) inhibits a Ca2+/calmodulin-dependent protein phosphatase, calcineurin, which regulates signal transduction. We isolated and characterized cyclophilin A mutations that confer CsA resistance in a Saccharomyces cerevisiae strain whose growth is CsA-sensitive. Three mutations (G70S, H90Y, and G102A) alter single amino acids conserved between yeast and human cyclophilin A, which structural analyses implicate in CsA binding to human cyclophilin A. By Western analysis, all three mutant proteins are expressed in yeast. In vitro, two purified mutant cyclophilins (G70S, G102A) retain prolyl isomerase activity and have moderately reduced affinity for CsA and calcineurin but, when bound to CsA, do bind and inhibit calcineurin phosphatase activity. In contrast, the purified H90Y mutant cyclophilin is dramatically decreased in prolyl isomerase activity, CsA affinity, and calcineurin binding and inhibition. These studies identify conserved cyclophilin A residues that participate in CsA binding and catalysis.

Perforation of the sigmoid colon following ingestion of a dental plate

The authors report on the perforation of the sigmoid colon in a 48-year-old male following the accidental ingestion of a partial dental plate. Sharp, pointed objects may perforate the bowel and surgery should be considered. A review of the literature revealed no previously reported cases.

Gene disruption with PCR products in Saccharomyces cerevisiae

We describe here the generation of gene disruption constructs using PCR amplification of selectable markers with primers that provide homology to the target gene of interest. We find that regions of homology as short as 38 to 50 bp suffice to mediate homologous recombination in yeast. We describe applications of this technology to three specific yeast genes that would have been difficult to disrupt with current methods. By dispensing with the need to either clone the gene of interest or engineer a standard disruption construct, this method should facilitate analysis of sequenced genes of unknown function, which will soon include the entire yeast genome.

Directed tagging of the Arabidopsis FATTY ACID ELONGATION1 (FAE1) gene with the maize transposon activator

The FATTY ACID ELONGATION1 (FAE1) gene of Arabidopsis is required for the synthesis of very long chain fatty acids in the seed. The product of the FAE1 gene is presumed to be a condensing enzyme that extends the chain length of fatty acids from C18 to C20 and C22. We report here the cloning of FAE1 by directed transposon tagging with the maize element Activator (Ac). An unstable fae1 mutant was isolated in a line carrying Ac linked to the FAE1 locus on chromosome 4. Cosegregation and reversion analyses established that the new mutant was tagged by Ac. A DNA fragment flanking Ac was cloned by inverse polymerase chain reaction and used to isolate FAE1 genomic clones and a cDNA clone from a library made from immature siliques. The predicted amino acid sequence of the FAE1 protein shares homology with those of other condensing enzymes (chalcone synthase, stilbene synthases, and beta-ketoacyl-acyl carrier protein synthase III), supporting the notion that FAE1 is the structural gene for a synthase or condensing enzyme. FAE1 is expressed in developing seed, but not in leaves, as expected from the effect of the fae1 mutation on the fatty acid compositions of those tissues.

Competition between rBPI23, a recombinant fragment of bactericidal/permeability-increasing protein, and lipopolysaccharide (LPS)-binding protein for binding to LPS and gram-negative bacteria

Lipopolysaccharide (LPS)-binding protein (LBP) and bactericidal/permeability-increasing protein (BPI) are two structurally related lipid A-binding proteins with divergent functional activities. LBP mediates activation of macrophage and other proinflammatory cells. In contrast, BPI has potent bactericidal and LPS-neutralizing activities. A recombinant fragment of BPI (rBPI23) retains the potent biological activities of the holo protein and may represent a novel therapeutic agent for the treatment of gram-negative infections, sepsis, and endotoxemia. For therapeutic effectiveness in many clinical situations, rBPI23 will have to successfully compete with high serum levels of LBP for binding to endotoxin and gram-negative bacteria. The relative binding affinities of rBPI23 and human recombinant LBP (rLBP) for lipid A and gram-negative bacteria were evaluated. The binding of both proteins to lipid A was specific and saturable with apparent Kds of 2.6 nM for rBPI23 and 58 nM for rLBP. rBPI23 was approximately 75-fold more potent than rLBP in inhibiting the binding of 125I-rLBP to lipid A. The binding affinity of rBPI23 (Kd = 70 nM) for Escherichia coli J5 bacteria was also significantly higher than that of rLBP (Kd = 1,050 nM). In addition, rBPI23 at 0.2 micrograms/ml was able to inhibit LPS-induced tumor necrosis factor release from monocytes in the presence of 20 micrograms of rLBP per ml. These results demonstrate that rBPI23 binds more avidly to endotoxin than does rLBP and that, even in the presence of a 100-fold weight excess of rLBP, rBPI23 effectively blocks the proinflammatory response of peripheral blood mononuclear cells to endotoxin.

Functional domains of recombinant bactericidal/permeability increasing protein (rBPI23)

The 23-kDa recombinant amino-terminal bactericidal/permeability increasing protein fragment (rBPI23) has all of the antibacterial and antiendotoxin properties of the holoprotein. In the current studies, we have identified multiple active domains within rBPI23 with chemical and proteolytic cleavage fragments and with synthetic overlapping peptides. We also demonstrate a novel, high affinity heparin binding property for rBPI23, in addition to its established bactericidal and lipopolysaccharide binding properties. Cleavage fragments and synthetic, overlapping peptides of rBPI23 were analyzed for inhibition of the lipopolysaccharide-induced Limulus amebocyte lysate reaction, for bactericidal activity, and for heparin binding. Three separate, active domains were identified in amino acid regions 17-45, 65-99, and 142-169. A single synthetic peptide (85-99) was bactericidal. These results indicate that rBPI23 is comprised of three separate functional domains which contribute to the high affinity interaction of rBPI23 with Gram-negative bacteria. The individual activity of each domain and the cooperative interaction among domains provide the basis for developing rBPI23 analogues with increased biologic efficacy.

Tidal volume, lung hyperinflation and arterial oxygenation during general anaesthesia

Impaired pulmonary oxygen (O2) exchange is common during general anaesthesia but there is no clinical unanimity as to methods of prevention or treatment. We studied 14 patients at risk for pulmonary dysfunction because of increased age, obesity, cigarette smoking, or chronic lung disease. Pulmonary O2 exchange was measured during four conditions of ventilation: awake spontaneous, conventional tidal volume (CVT, 7 ml.kg-1) or high tidal volume (HVT, 12 ml.kg-1) controlled ventilation, and five min after manual hyperinflation (HI) of the lungs. The FIO2 was controlled at 0.5, and FETCO2 was kept constant by adding dead space during HVT. Eight patients were ventilated with N2O/O2 and six with air/O2. Arterial blood gases were used to calculate the (A-a)DO2. In seven patients (A-a)DO2 worsened after induction of anaesthesia, while in seven there was no change or an improvement. Manual HI significantly reduced (A-a)DO2, but changing tidal volume (VT) had no effect. Using a multivariate model to predict O2 exchange, obesity and type of surgery were significantly associated with worsening, while level of VT and inspiratory gas (N2O or N2) were not significant predictors. Thus patient and surgical factors were more important determinants of pulmonary gas exchange during anaesthesia than were tidal volume or inspiratory gas. Manual HI is a simple and effective manoeuvre to improve gas exchange.

Ambulance response time to emergency departments

The study was conducted to ascertain the time it takes an ambulance team to reach a patient and transport the patient to an emergency department after a 995 call. One hundred and sixty-two cases brought to two emergency departments (Singapore General Hospital and Tan Tock Seng Hospital) between 11 March 1992 and 16 March 1992 were studied. The information was obtained from ambulance officers of the Singapore Civil Defence Force. It took an average of 11.40 +/- 4.88 minutes for an ambulance team to reach a patient and 30.50 +/- 10.62 minutes for the patient to reach an emergency department after a 995 call. With the present level of staff in Singapore, basic life support care starts 11.40 minutes and advanced life support care 30.50 minutes after a 995 call. These times are unacceptable if it involves a cardiac arrest or a trauma patient. Factors which cause these long time intervals include traffic congestion, inadequate public education, location of patient (whether on ground level or highrise) and distance from the emergency departments.

The role of IgA anti-HLA class I antibodies in kidney transplant survival

The unusually high 88% one-year cadaver kidney graft survival rate in patients with IgA nephropathy (IgAN) prompted us to investigate the influence of IgA anti-HLA class I antibodies on subsequent graft survival. We found that patients with various original diseases with IgA antibodies to the HLA molecule had high 91% one-year graft survival compared with 58% one-year survival for those who did not have preformed IgA antibodies against the HLA molecule prior to transplantation (P < 0.0005). The IgA antibodies were detected by reaction with class I HLA molecules isolated by capture with monoclonal antibody and detected with an enzyme-linked immunosorbent assay. In contrast, IgG antibodies to the HLA molecule resulted in a lower one-year graft survival rate (74%) than in those patients without IgG antibodies (87%) (p = 0.08). IgA antibodies to the HLA molecule, when present, tended to react at a high frequency on a random lymphocyte panel. These findings suggest that sensitization resulting in IgA anti-HLA antibodies may counteract the deleterious effect of an IgG antibody response in clinical kidney transplantation.

Preferential transposition ofAc to linked sites in Arabidopsis

We have investigated the pattern of transposition of an intact, 4.6-kbAc element inArabidopsis thaliana. Because the trans-acting transposition function (transposase) ofAc is not fully penetrant in Arabidopsis, it is not possible to use it as a diagnostic feature to scoreAc genetically, as has been done in maize and tobacco. Instead, the presence or absence of a transposedAc (trAc) was monitored by Southern blots. Germinal transpositions from the marker SPT::Ac were selected using a streptomycin germination assay and scored for the presence of atrAc. Segregation of thetrAc element and the SPT donor locus was scored in the F2 progeny of the germinal revertants, and the recombination fraction between thetrAc element and SPT was estimated by the method of maximum likelihood. We have found that, as in maize and tobacco, receptor sites fortrAcs in Arabidopsis tend to be linked to theAc donor locus.

Effects of gene dosage and sequence modification on the frequency and timing of transposition of the maize element Activator (Ac) in tobacco

The effect of Ac copy number on the frequency and timing of germinal transposition in tobacco was investigated using the streptomycin phosphotransferase gene (SPT) as an excision marker. The activity of one and two copies of the element was compared by selecting heterozygous and homozygous progeny of transformants carrying single SPT::Ac inserts. It was observed that increasing gene copy not only increases the transposition frequency, but also occasionally alters the timing of transposition such that earlier events are obtained. The result is that some homozygous plants generate multiple streptomycin resistant progeny carrying the same transposed Ac (trAc) element. We have also investigated the effect of modification of the sequence in the region around 82 bp downstream of the polyadenylation site and 177 bp from the 3' end of the element on germinal excision frequencies. Alteration of three bases to create a Bgl II site at this location caused a minor decrease in germinal excision events, but insertion of four bases to create a Cla I site caused a 10-fold decrease in the transposition activity of the Ac element.

Obstetric admissions to the intensive care unit--a retrospective review

A five-year retrospective study of obstetric admissions to the Surgical Intensive Care Unit (SICU) in the National University Hospital, Singapore was carried out with the aim of determining the incidence, causes and outcome of these admissions. Most of the patients were admitted following emergency caesarean sections. Obstetric complications was the reason for admission in 56.8% with hypertensive disease of pregnancy being the major cause and haemorrhage accounting for the rest. Anaesthetic complications accounted for 21.6% of admissions and these included difficult intubation, aspiration pneumonitis, cardiac arrhythmias and respiratory depression. Medical complications due to cardiovascular disease, autoimmune disease and malignancy also accounted for 21.6% of admissions. Only 37 out of 16264 deliveries (0.22%) required intensive care support. The median of duration of stay was one day.

Effects of home bleaching preparations on composite resin color

The lightening of teeth is done professionally by exposure to warm hydrogen peroxide solutions or at home with an active bleaching gel of perhydrol urea or carbamide peroxide. This study compared the effects of two commercial bleaching gels on the color of composite resin with those in a previous study using the dental office technique. Commercial composite resins test specimens were exposed to the bleaching gels or water (control) for 312 hours at 37 degrees C at 100% relative humidity. Color change value was calculated with before-and-after solution exposure L*a*b* color values. ANOVA (alpha = 0.01) revealed no differences in the color of the specimens after use of the test solutions. All color change values were less than 2 or the normal limit of visual acuity. No visual color change was evident for these composite resins. The at-home method recorded no shade-altering effects compared with the professional technique, which created a noticeable color change.

Reactivity of monoclonal antibody E5 with endotoxin. I. Binding to lipid A and rough lipopolysaccharides

The murine IgM monoclonal antibody (mAb) E5 was produced by a hybridoma derived from spleen cells of a mouse immunized with the J5 rough mutant of Escherichia coli O111:B4. In a multicenter randomized placebo-controlled clinical trial, E5 has been shown to reduce significantly the mortality and morbidity of patients with Gram-negative sepsis. The characteristics of E5 binding to endotoxin were studied in vitro. We report here the results of binding to an extensive panel of rough lipopolysaccharide (LPS) and lipid A preparations. Using standard immunologic techniques, including enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA), as well as an antibody capture assay using immobilized antibody and a chromogenic Limulus amebocyte lysate (LAL) detection system, E5 was shown to bind to all rough LPS (chemotypes Ra through Re from Salmonella minnesota and E. coli J5) and lipid A preparations tested. E5 displayed a Kd for Ra LPS of approximately 6.5 nM. These results confirm and extend those reported previously and provide evidence that E5 binds specifically to lipid A and to the lipid A moiety of rough LPS.

Reactivity of monoclonal antibody E5 with endotoxin. II. Binding to short- and long-chain smooth lipopolysaccharides

The murine monoclonal IgM antibody E5 has been shown to significantly reduce the mortality and morbidity of patients with Gram-negative sepsis in a multicenter randomized placebo-controlled clinical trial. The in vitro binding characteristics of monoclonal antibody (mAb) E5 were studied using highly purified smooth lipopolysaccharide (LPS) isolated from a variety of clinically relevant, wild-type Gram-negative bacteria. Using a sensitive antibody-capture assay which involves immobilized mAb E5 and a chromogenic Limulus amebocyte lysate (LAL) LPS-detection system, mAb E5 was shown to bind to all 15 smooth LPS preparations tested, including LPS isolated from Escherichia, Klebsiella, Proteus, Pseudomonas, Salmonella, Serratia and Yersinia species. When LPS was fractionated according to size by size-exclusion chromatography, mAb E5 was shown to bind to smooth LPS molecules that have long as well as short O-polysaccharide chains. These results confirm and extend those reported previously and demonstrate that the anti-lipid A mAb E5 binds specifically to a diverse spectrum of smooth LPS isolated from wild-type Gram-negative bacteria.

Germinal and somatic activity of the maize element Activator (Ac) in Arabidopsis

We have investigated the germinal and somatic activity of the maize Activator (Ac) element in Arabidopsis with the objective of developing an efficient transposon-based system for gene isolation in that plant. Transposition activity was assayed with a chimeric marker that consists of the cauliflower mosaic virus 35S promoter and a bacterial streptomycin phosphotransferase gene (SPT). Somatic activity was detected in seedlings germinated on plates containing streptomycin as green-resistant sectors against a background of white-sensitive cells. Germinal excisions resulted in fully green seedlings. The transposition frequency was extremely low when a single copy of the transposon was present, but appeared to increase with an increase in Ac copy number. Plants that were selected as variegated produced an increased number of green progeny. The methylation state of the Ac elements in lines with either low or high levels of excision was assessed by restriction analysis. No difference was found between these lines, indicating that the degree of methylation did not contribute to the level of Ac activity. Germinal excision events were analyzed molecularly and shown to carry reinserted transposons in about 50% of the cases. In several instances, streptomycin-resistant siblings carried the same transposed Ac element, indicating that excision had occurred prior to meiosis in the parent. We discuss parameters that need to be considered to optimize the use of Ac as a transposon tag in Arabidopsis.

Large tidal volume ventilation improves pulmonary gas exchange during lower abdominal surgery in Trendelenburg's position

Impaired pulmonary gas exchange is a common complication of general anaesthesia. Periodic hyperinflation of the lungs and large tidal volume ventilation were the first preventive measures to be widely embraced, but their effectiveness in clinical practice has never been clearly established by controlled clinical studies. To assess their effects in high-risk patients we studied 24 adults having lower abdominal gynaecological surgery in the Trendelenburg (head down) position. Pulmonary oxygen exchange was determined during four steady-states: awake control (AC), after 30 min of conventional tidal volume (CVT, 7.5 ml.kg-1) or high tidal volume (HVT, 12.7 ml.kg-1) ventilation, introduced in random order, and five minutes after manual hyperinflations (HI) of the lungs. The patients' lungs were ventilated with air/O2 by an Ohmeda volume-controlled ventilator via a circle system. The FIO2 was controlled at 0.5, and FETCO2 was controlled by adding dead space during HVT. Arterial blood gas analysis was used to calculate the oxygen tension-based indices of gas exchange. There was significant deterioration of (A-a)DO2 at 30 min in Group A, whose lungs were first ventilated with CVT (81.6 +/- 7.2 to 166.8 +/- 13.7 mmHg, P less than 0.001); but not in Group B, whose lungs were first ventilated with HVT (77.0 +/- 9.9 to 104.4 +/- 16.8 mmHg). When Group A and B data were pooled there was no difference between randomized CVT and HVT, but improvement occurred after HI. In this model of compromised O2 exchange large inflation volumes (HVT and HI) were of considerable clinical benefit, HVT prevented and HI reversed the gas exchange disorder.

An X-linked zinc finger gene mapping to Xq21.1-q21.3 closely related to ZFX and ZFY: possible origins from a common ancestral gene

We describe a new zinc finger gene sequence (CMPX1 or HGM symbol ZNF6; isolated by cross-hybridization of ZFY to clones in a testis cDNA library) which possesses a zinc finger domain closely related to the transcriptional activator gene ZFX. The putative acidic activation domain is only 11.5% homologous with ZFX, whereas the putative DNA binding domain shares 75% homology and shows the same organisation composed of a basic two fingered repeat unit. ZNF6 has an unusually large 5' untranslated region (UTR) of 1.2 Kb which contains 26 potential ATG initiation codons, only one of which is associated with a long open reading frame. Southern and Northern blot analysis has shown that this 5' UTR is shared with many other sequences in the genome and transcribed associated with a large range of mRNA species. In situ hybridisation, analysis of somatic cell hybrids and male individuals carrying deleted X chromosomes have mapped the gene to Xq21.1-q21.3. The gene is highly conserved amongst the primates, in the mouse and can be detected weakly in the genome of a metatherian mammal (possum). Dosage in male and female mice indicates that it is also X-linked in this species. Possible origins of ZFX, ZFY and CMPX1 from a common ancestral gene are discussed.

A nursing model for orthopaedics

A nurse manager, an educationalist and a clinician describe their nursing model, which has been implemented on an orthopaedic unit. Based on an appreciation of the unique nature of the nurse-patient relationship, the model aims to foster and develop patient empowerment as a means of encouraging rehabilitation.

Preferential transposition of the maize element Activator to linked chromosomal locations in tobacco

The autonomous maize transposon Activator (Ac) has been used in maize for gene isolation by tagging and may prove similarly useful in other species. To test the feasibility of gene tagging with heterospecific transposons, we have examined three key genetic properties of a slightly modified Ac in tobacco. First, we show that frequencies of germinal excision of this Ac element from the antibiotic resistance gene streptomycin phosphotransferase can be comparable with or slightly lower than in maize. Second, we show that about half of the progeny carrying a germinal excision product also carry a transposed Ac. Last, we have mapped transposed Ac locations relative to the streptomycin transferase gene excision product and have shown that as in maize Ac in tobacco preferentially transposes to genetically linked sites.

Cloning of rat "prion-related protein" cDNA

Rat prion-related protein (PrP) cDNA has been cloned and sequenced. Comparison of this cDNA with those from human, hamster, and mouse indicates extremely high conservation (about 95%). The deduced partial rat PrP possesses: (a) a highly conserved region composed of repetitive sequences in what is presumably an extracellular domain, (b) a hydrophobic transmembrane domain, (c) a highly charged region which should stop membrane transfer, (d) a substantial cytoplasmic domain (which contains all of the nonconservative substitutions and a high proportion of conservative substitutions), and (e) a hydrophobic C-terminus. Dot and Northern blot analyses suggest a limited expression of PrP in rat tissues and indicate that PrP expression is decreased in the brain during the acute phase response systemically. Our results lend support to the notion that PrP is a highly conserved, normal cellular membrane protein of essential (although unknown) biologic function, which may be deposited in fibrillar amyloid form as a result of abnormal processing.

Regulatory factors specific for adult and embryonic globin genes may govern their expression in erythroleukemia cells

In order to test if trans-acting regulatory factors specific for globin genes of the adult and embryonic stages of development exist in erythroid cells, transcriptionally active embryonic and adult globin genes on the same chromosome were transferred by cell fusion from the human leukemia cell K562 into phenotypically adult mouse erythroleukemia cells. Restriction-fragment-length polymorphisms of the K562 zeta (embryonic) globin genes were used to establish that all three copies of human chromosome 16 present in the K562 cell showed the same pattern of human globin gene expression after transfer to the mouse erythroleukemia cell. Adult (alpha) but not embryonic (zeta) human globin mRNA was detected in all nine of the independently derived mouse erythroleukemia hybrid cells, each of which contained human chromosome 16. Restriction endonuclease studies of the K562 alpha- and zeta-globin genes after transfer into the mouse erythroleukemia cell showed no evidence of rearrangements or deletions that could explain this loss of zeta-globin gene expression. These data suggest that regulation of globin gene expression in these erythroleukemia cells involves trans-acting regulatory factors specific for the adult and embryonic stages of development.