The effect of interferon beta-1b treatment on MRI measures of cerebral atrophy in secondary progressive multiple sclerosis. European Study Group on Interferon beta-1b in secondary progressive multiple sclerosis

The recently completed European trial of interferon beta-1b (IFNbeta-1b) in patients with secondary progressive multiple sclerosis (SP multiple sclerosis) has given an opportunity to assess the impact of treatment on cerebral atrophy using serial MRI. Unenhanced T(1)-weighted brain imaging was acquired in a subgroup of 95 patients from five of the European centres; imaging was performed at 6-month intervals from month 0 to month 36. A blinded observer measured cerebral volume on four contiguous 5 mm cerebral hemisphere slices at each time point, using an algorithm with a high level of reproducibility and automation. There was a significant and progressive reduction in cerebral volume in both placebo and treated groups, with a mean reduction of 3.9 and 2.9%, respectively, by month 36 (P = 0.34 between groups). Exploratory subgroup analyses indicated that patients without gadolinium (Gd) enhancement at the baseline had a greater reduction of cerebral volume in the placebo group (mean reduction at month 36: placebo 5.1%, IFNbeta-1b 1.8%, P < 0.05) whereas those with Gd-enhancing lesions showed a trend to greater reduction of cerebral volume if the patient was on IFNbeta-1b (placebo 2.6%, IFNbeta-1b 3.7%; P > 0.05). These results are consistent with ongoing tissue loss in both arms of this study of secondary progressive multiple sclerosis. This finding is concordant with previous observations that disease progression, although delayed, is not halted by IFNbeta. The different pattern seen in patients with and without baseline gadolinium enhancement suggests that part of the cerebral volume reduction observed in IFNbeta-treated patients may be due to the anti-inflammatory/antioedematous effect of the drug. Longer periods of observation and larger groups of patients may be needed to detect the effects of treatment on cerebral atrophy in this population of patients with advanced disease.

A new thermoactive pullulanase from Desulfurococcus mucosus: cloning, sequencing, purification, and characterization of the recombinant enzyme after expression in Bacillus subtilis

The gene encoding a thermoactive pullulanase from the hyperthermophilic anaerobic archaeon Desulfurococcus mucosus (apuA) was cloned in Escherichia coli and sequenced. apuA from D. mucosus showed 45.4% pairwise amino acid identity with the pullulanase from Thermococcus aggregans and contained the four regions conserved among all amylolytic enzymes. apuA encodes a protein of 686 amino acids with a 28-residue signal peptide and has a predicted mass of 74 kDa after signal cleavage. The apuA gene was then expressed in Bacillus subtilis and secreted into the culture fluid. This is one of the first reports on the successful expression and purification of an archaeal amylopullulanase in a Bacillus strain. The purified recombinant enzyme (rapuDm) is composed of two subunits, each having an estimated molecular mass of 66 kDa. Optimal activity was measured at 85 degrees C within a broad pH range from 3.5 to 8.5, with an optimum at pH 5.0. Divalent cations have no influence on the stability or activity of the enzyme. RapuDm was stable at 80 degrees C for 4 h and exhibited a half-life of 50 min at 85 degrees C. By high-pressure liquid chromatography analysis it was observed that rapuDm hydrolyzed alpha-1,6 glycosidic linkages of pullulan, producing maltotriose, and also alpha-1,4 glycosidic linkages in starch, amylose, amylopectin, and cyclodextrins, with maltotriose and maltose as the main products. Since the thermoactive pullulanases known so far from Archaea are not active on cyclodextrins and are in fact inhibited by these cyclic oligosaccharides, the enzyme from D. mucosus should be considered an archaeal pullulanase type II with a wider substrate specificity.

Nitric oxide prevents cardiovascular disease and determines survival in polyglobulic mice overexpressing erythropoietin

Nitric oxide (NO) induces vasodilatatory, antiaggregatory, and antiproliferative effects in vitro. To delineate potential beneficial effects of NO in preventing vascular disease in vivo, we generated transgenic mice overexpressing human erythropoietin. These animals induce polyglobulia known to be associated with a high incidence of vascular disease. Despite hematocrit levels of 80%, adult transgenic mice did not develop hypertension or thromboembolism. Endothelial NO synthase levels, NO-mediated endothelium-dependent relaxation and circulating and vascular tissue NO levels were markedly increased. Administration of the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) led to vasoconstriction of peripheral resistance vessels, hypertension, and death of transgenic mice, whereas wild-type siblings developed hypertension but did not show increased mortality. L-NAME-treated polyglobulic mice revealed acute left ventricular dilatation and vascular engorgement associated with pulmonary congestion and hemorrhage. In conclusion, we here unequivocally demonstrate that endothelial NO maintains normotension, prevents cardiovascular dysfunction, and critically determines survival in vivo under conditions of increased hematocrit.

Protein mapping by two-dimensional high performance liquid chromatography

Current developments in drug discovery in the pharmaceutical industry require highly efficient analytical systems for protein mapping providing high resolution, robustness, sensitivity, reproducibility and a high throughput of samples. The potential of two-dimensional (2D) HPLC as a complementary method to 2D-gel electrophoresis is investigated, especially in view of speed and repeatability. The method will be applied for proteins of a molecular mass <20 000 which are not well resolved in 2D-gel electrophoresis. The 2D-HPLC system described in this work consisted of anion- or cation-exchange chromatography in the first dimension and reversed-phase chromatography in the second dimension. We used a comprehensive two-dimensional approach based on different separation speeds. In the first dimension 2.5 microm polymeric beads bonded with diethylaminoethyl and sulfonic acid groups, respectively, were applied as ion exchangers and operated at a flow-rate of 1 ml/min. To achieve very high-speed and high-resolution separations in the second dimension, short columns of 14 x 4.6 mm I.D. with 1.5 microm n-octadecyl bonded, non-porous silica packings were chosen and operated at a flow-rate of 2.5 ml/min. Two reversed-phase columns were used in parallel in the second dimension. The analyte fractions from the ion-exchange column were transferred alternatively to one of the two reversed-phase columns using a 10-port switching valve. The analytes were deposited in an on-column focusing mode on top of one column while the analytes on the second column were eluted. Proteins, which were not completely resolved in the first dimension can, in most cases, be baseline-separated in the second dimension. The total value of peak capacity was calculated to 600. Fully unattended overnight runs for repeatability studies proved the applicability of the system. The values for the relative standard deviation (RSD) of the retention times of proteins were less than 1% (n = 15), while the RSDs of the peak areas were less than 15% (n = 15) on average. The limit of detection was 300 ng of protein on average and decreased to 50 ng for ovalbumin. The 2D-HPLC system offered high-resolution protein separations with a total analysis time of less than 20 min, equivalent to the run time of the first dimension.

Myocardial contractility after infarction and carnitine palmitoyltransferase I inhibition in rats

Inhibition of carnitine palmitoyltransferase I with etomoxir increases sarcoplasmic reticulum Ca(2+)-transport and V(1) isomyosin expression. To test whether etomoxir attenuates contractile dysfunction after myocardial infarction, we compared the contractility of papillary muscles from etomoxir- and placebo-treated rats 6 weeks after infarction. Etomoxir induced cardiac hypertrophy in animals with small infarctions, and enhanced compensatory heart growth at large infarct size. Contractile function of papillary muscles from etomoxir-treated rats was improved particularly in animals with small infarctions. Thus, induction of mild cardiac hypertrophy by etomoxir in rats with small infarctions may be beneficial for myocardial performance.

Transfusion errors in New York State: an analysis of 10 years' experience

BACKGROUND

While public focus is on the risk of infectious disease from the blood supply, transfusion errors also contribute significantly to adverse outcomes. This study characterizes such errors.

STUDY DESIGN AND METHODS

The New York State Department of Health mandates the reporting of transfusion errors by the approximately 256 transfusion services licensed to operate in the state. Each incident from 1990 through 1998 that resulted in administration of blood to other than the intended patient or the issuance of blood of incorrect ABO or Rh group for transfusion was analyzed.

RESULTS

Erroneous administration was observed for 1 of 19, 000 RBC units administered. Half of these events occurred outside the blood bank (administration to the wrong recipient, 38%; phlebotomy errors, 13%). Isolated blood bank errors, including testing of the wrong specimen, transcription errors, and issuance of the wrong unit, were responsible for 29 percent of events. Many events (15%) involved multiple errors; the most common was failure to detect at the bedside that an incorrect unit had been issued.

CONCLUSION

Transfusion error continues to be a significant risk. Most errors result from human actions and thus may be preventable. The majority of events occur outside the blood bank, which suggests that hospitalwide efforts at prevention may be required.

Pentoxifylline improves circulatory and metabolic recovery after cardiopulmonary resuscitation

BACKGROUND

To evaluate the effectiveness of a bolus application of pentoxifylline (PTXF) at the beginning of CPR in a standardized resuscitation animal model.

METHODS AND RESULTS

In a laboratory model of cardiac arrest, 12 Wistar rats (382-413 g) were randomized into two groups. Both groups underwent 4 min of cardiopulmonary arrest induced by a transthoracic application of a fibrillating current of 10 mA. At the beginning of CPR, group one (n=6) received a bolus injection of 10 mg kg(-1) body weight PTXF versus sodium chloride in group two (controls: n=6). All animals developed a severe lactate acidosis during and after CPR but in PTXF treated animals acid-base values returned to baseline pattern. During return of spontaneous circulation (ROSC) in the PTXF group lactate concentration decreased from 13.4+/-2.1 to 1.9+/-0.7 mmol l(-1) within 60 min (P<0.01). In control animals, lactate values remained high (10.8+/-3.5 by 60 min, P<0.01). After bolus injection of PTXF pH increased from 6.93+/-0.06 to 7.29+/-0.13 within 60 min of ROSC versus 6.85+/-0.05 to 6.97+/-0.23 in sodium chloride treated animals (P<0.01). Within 5 min of ROSC, PTXF treated animals achieved higher oxygenation values (PTXF P(a)O(2)=216.9+/-62.5 mmHg, control 132. 2+/-15.1 mmHg, P<0.01).

CONCLUSIONS

Administration of PTXF at the beginning of CPR improved macrocirculation, acid-base status and arterial oxygenation.

Imprinting centre deletions in two PWS families: implications for diagnostic testing and genetic counseling

Prader-Willi syndrome (PWS) is a complex genetic syndrome involving imprinted genes on chromosome 15. It is usually sporadic, and very few affected siblings have been described. Here, we report the clinical and molecular findings in two families with a microdeletion affecting the chromosome 15 imprinting centre (IC). Carrier males have a 50% risk of having children with an imprinting defect leading to PWS, and in one of the two families, a father has two affected daughters. In the other family, diagnostic testing was confounded by the presence of a neutral microdeletion close to the IC. The silent transmission of PWS IC deletions through the female germline and the occurrence of neutral microdeletions close to the IC can impose considerable problems on diagnostic testing and genetic counselling in affected families.

The transport modifier RS1 is localized at the inner side of the plasma membrane and changes membrane capacitance

Previously we cloned membrane associated (M(r) 62000-67000) polypeptides from pig (pRS1), rabbit (rbRS1) and man (hRS1) which modified transport activities that were expressed in Xenopus laevis oocytes by the Na(+)-D-glucose cotransporter SGLT1 and/or the organic cation transporter OCT2. These effects were dependent on the species of RS1 and on the target transporters. hRS1 and rbRS1 were shown to be intronless single copy genes which are expressed in various tissues and cell types. Earlier immunohistochemical data with a monoclonal IgM antibody suggested an extracellular membrane association of RS1. In the present paper antibodies against recombinant pRS1 were raised and the distribution and membrane localization of RS1 reevaluated. After subcellular fractionation of renal cortex RS1 was found associated with brush border membranes and an about 1:200 relation between RS1 and SGLT1 protein was estimated. Also after overexpression in X. laevis oocytes RS1 was associated with the plasma membrane, however, at variance to the kidney it was also observed in the cytosol. Labeling experiments with covalently binding lipid-permeable and lipid-impermeable biotin analogues showed that RS1 is localized at the inner side of the plasma membrane. Western blots with plasma membranes from Xenopus oocytes revealed that SGLT1 protein in the plasma membrane was reduced when hRS1 was coexpressed with human SGLT1 which leads to a reduction in V(max) of expressed glucose transport. Measurements of membrane capacitance and electron microscopic inspection showed that the expression of hRS1 leads to a reduction of the oocyte plasma membrane surface. The data suggest that RS1 is an intracellular regulatory protein that associates with the plasma membrane. Overexpression of RS1 may effect the incorporation and/or retrieval of transporters into the plasma membrane.

Clinical predominance of proximal upper limb weakness in CMT1A syndrome

We report an Austrian family with proximal muscle weakness and wasting predominantly of the shoulder girdle musculature, normal or slightly reduced distal muscle power, mild foot deformity, absent or reduced tendon reflexes in the lower limbs, and normal or slightly diminished sensation. Electrophysiologically, motor nerve conduction velocities were slowed to less than 33 m/s, distal latencies were prolonged, and compound motor action potentials were low. Sensory nerve conduction velocities were extremely reduced or no sensory potentials were recordable. Genetic testing in three affected individuals revealed a duplication of the chromosomal region 17p11.2. In addition, genetic testing for facioscapulohumeral muscular dystrophy (FSHD) revealed a 33 kb EcoRI fragment on chromosome 4q35 in one affected individual and in the clinically normal parent, whereas in a second affected person normal DNA-sizes were observed. These clinical findings define a new phenotypic variant associated with the Charcot-Marie-Tooth 1A duplication. This may be due to a mutation in another gene contained in the 1.5 Mb duplication although mutations in the peripheral myelin protein 22 gene have been excluded. Alternatively, the genetic background of other genes in the family may modify the phenotypic expression, as found in other inherited diseases. The unusual phenotype cannot be explained by the concomitant presence of FSHD despite some evidence for coexistance in one individual.

Phenotypic and genotypic heterogeneity in hereditary motor neuronopathy type V: a clinical, electrophysiological and genetic study

We report on a large four-generation Austrian family with autosomal dominant distal hereditary motor neuronopathy type V (distal HMN V). Forty-seven at-risk family members, of whom 21 were definitely affected, underwent detailed clinical, electrophysiological and genetic studies. The age at onset was in the second decade of life in most affected individuals, but clinical presentation was rather variable. While the majority of patients were primarily disabled by progressive asymmetrical wasting of the thenar and the first dorsal interosseus muscles, others had marked foot deformity and gait disturbance with the occasional absence of hand involvement. Sensation sense was normal except for the reduced response to vibration. Many individuals showed brisk tendon reflexes and some elevated muscle tone in the lower limbs, but extensor plantar responses were rarely observed. Electrophysiological evaluation revealed normal or reduced motor nerve conduction velocities, normal or prolonged distal motor latencies, and low compound motor action potentials, depending on the degree of muscle wasting. Sensory nerve studies were usually within the normal range or slightly to moderately abnormal in older or severely affected persons. Electromyography showed high-amplitude motor unit potentials and reduced recruitment compatible with anterior horn cell degeneration. Central motor conduction times were prolonged in two-thirds of the patients. Molecular genetic studies excluded Charcot-Marie-Tooth 1A syndrome and proximal spinal muscular atrophy linked to chromosome 5q as well as the known gene loci for distal HMN II on chromosome 12q, HMN V on chromosome 7p and juvenile amyotrophic lateral sclerosis on chromosome 9q. The findings in this family thus provide detailed clinical and electrophysiological information on HMN V and demonstrate broad phenotypic variability in this disorder. Hallmark features are discussed that appear to be most reliable to differentiate this type of HMN V from other variants of hereditary neuropathies, and a set of diagnostic criteria is proposed. Furthermore, this is the first report of prolonged central motor conduction times in HMN V, which indicates additional involvement of the central motor pathways in this disease. Finally, molecular genetic studies demonstrate genetic heterogeneity, suggesting the existence of at least a second genetic subtype in HMN V.

Diagnosing PID--getting the balance right

The objective of the study was to determine the clinical manifestations and diagnostic criteria used to diagnose presumptive pelvic inflammatory disease (PID) at the Sydney Sexual Health Centre (SSHC). The study was a retrospective, case-note review of all women diagnosed with presumptive PID between April 1991 and December 1997. Seven hundred and thirteen women were included. The commonest recorded symptoms were vaginal discharge (68%), lower abdominal pain (65%) and dyspareunia (57%), while adnexal tenderness (83%), cervical motion tenderness (75%) and cervicitis (56%) were the most frequently recorded examination findings. Sixty-two per cent were prescribed doxycycline and metronidazole. The recording of signs and symptoms in women with presumptive PID was poor and only 22% met the current Centers for Disease Control (CDC) diagnostic criteria. It is likely that PID is over diagnosed in this group of women. This may lead to under diagnosis of other conditions causing pelvic pain and may be detrimental to reproductive health.

Endomyocardial biopsy in pediatric heart transplant recipients: a useful exercise? (Analysis of 1,169 biopsies)

The objective of this study was to define the diagnostic yield for endomyocardial biopsy (EMB) procedures performed for various indications in a large pediatric heart transplant population. Endomyocardial biopsy procedure has been employed as the 'gold standard' for rejection surveillance. Previous studies have questioned the value of surveillance EMB beyond the early post-transplant period. We retrospectively reviewed data on 82 pediatric heart transplant recipients with serial EMB. A total of 1,169 EMB were performed during a follow-up period of 2-149 months (median 41 months). EMB were classified by age at transplantation, time from transplant, immunosuppressive regimen used [tacrolimus vs. cyclosporin A (CsA)] and indication, i.e. surveillance, follow-up after rejection or lowering of immunosuppression, non-specific clinical symptoms and graft dysfunction. During the first year after heart transplantation, surveillance EMB demonstrated significant rejection [International Society for Heart and Lung Transplantation (ISHLT) grade > or = 3A] in 18% of biopsies with the yield being 14-43% for all other indications. Surveillance EMB 1-5 yr post-transplantation were found to have a lower diagnostic yield in infants (4%, vs. 13% in children) and in patients with favorable first-year rejection history (9% vs. 17% in 'frequent rejectors'). Tacrolimus-based immunosuppression was associated with significantly less rejection, but only in the first year post-transplantation (14% in tacrolimus vs. 24% in CsA surveillance EMB, p = 0.035). Surveillance EMB remains an important diagnostic tool for rejection surveillance during the first 5 years after pediatric heart transplantation. Endomyocardial biopsy is particularly warranted after reduction of immunosuppression and for monitoring for ongoing rejection after treatment of acute rejection episodes.

Impairment and recovery of elementary cognitive function induced by hypoglycemia in type-1 diabetic patients and healthy controls

Although neuroendocrine changes after induction of hypoglycemia, in patients with diabetes and healthy persons, are thoroughly investigated, cognitive adaptation processes are still insufficiently understood. Changes in cognitive functions are mainly investigated by psychometric tests, which represent a summation of different cognitive processes. We aimed at dissecting cognitive adaptation into single components, i.e. stimulus selection, response choice, and reaction speed during a hyperinsulinemic hypoglycemic clamp in patients with type-1 diabetes and matched healthy controls. Using novel neurophysiological analyses, the event-related potentials of early stimulus selection (selection negativity) and response selection (lateralized readiness potential) were studied, in addition to reaction time (RT). A total of 12 diabetic patients and 12 normal volunteers were studied while receiving a hyperinsulinemic hypoglycemic clamp. RTs and the event-related potentials related to stimulus selection and response selection were significantly delayed during hypoglycemia in both groups, whereas early evoked potentials (P100) were unaltered. This suggests that hypoglycemia delays stimulus selection, with the consequence that also central and motor processing are delayed. In addition, patients with diabetes showed an earlier negative shift over the frontal cortex, which, when compared with the controls, reveals better adaptation to hypoglycemia in frontal cortical brain regions. After restoration of euglycemia stimulus selection, response selection and RT returned to baseline level in the type-1 group. In the control group, however, response selection and RTs were still delayed. This suggests that type-1 patients, possibly because of the past occurrence of hypoglycemic events, might be able to better cope with the hypoglycemic state than healthy volunteers who lack such a history. In summary, our data demonstrate, for the first time, that cognitive adaptation processes to an experimental hypoglycemic episode can clearly be dissected into their single components.

Neonatal herpes prevention: a minor public health problem in some communities

BACKGROUND

Neonatal herpes is a condition with high morbidity and mortality. The greatest risk occurs when the mother acquires herpes simplex virus (HSV) towards the end of pregnancy. A study from Seattle has suggested that the risk of acquisition of HSV during pregnancy was 3.7%. In Australia, HSV-2 infection is less common in pregnant women than in the United States. Consequently we conducted a study to establish HSV seroprevalence and the rate of HSV seroconversion in this population.

METHODS

The study was conducted at Westmead Hospital, Sydney, between June 1995 and April 1998. Women completed a questionnaire covering risk factors for the acquisition of genital herpes. A serum sample during pregnancy and a specimen of cord blood were obtained and tested for antibodies to HSV-2 using a type specific indirect enzyme linked immunosorbent assay (ELISA). Equivocal results were resolved by western blot. A subset of the paired sera was tested for antibodies to HSV-1. The data were analysed using SPSS.

RESULTS

326 of the 2616 (12.5%) women were HSV-2 seropositive. Three women (0.15%) acquired HSV-2 infection during pregnancy. None of the three babies of these mothers developed neonatal herpes. 416 maternal cord pairs were tested for HSV-1 antibodies and 330 (79.3%) were positive. No HSV-1 seroconversions occurred.

CONCLUSIONS

In this population, HSV acquisition was uncommon (0.34% per year) and neonatal herpes was rare. A cost effective analysis suggested that type specific serology to screen pregnant women and their partners in low prevalence communities was not cost effective.

Recurrent genetic aberrations in thymoma and thymic carcinoma

Apart from single reported aberrant karyotypes, genetic alterations in thymic epithelial neoplasms have not been investigated so far. In this study, 12 World Health Organization classification type A thymomas (medullary thymomas), 16 type B3 thymomas (well-differentiated thymic carcinomas), and nine type C thymomas, all of them primary thymic squamous cell carcinomas, were analyzed by comparative genomic hybridization and fluorescence in situ hybridization. With the exception of one single case, type A thymomas did not reveal chromosomal gains or losses in comparative genomic hybridization. In contrast, all type B3 thymomas showed chromosomal imbalances, with gain of 1q, loss of chromosome 6, and loss of 13q occurring in 11 (69%), six (38%), and five (31%) of 16 cases, respectively. In primary thymic squamous cell carcinoma, the most frequent chromosomal losses were observed for 16q (six of nine cases, 67%), 6 (4 of 9, 44%), and 3p and 17p (three of nine each, 33%), whereas recurrent gains of chromosomal material were gains of 1q (5 of 9, 56%), 17q, and 18 (three of nine each, 33%). This study shows that the distinct histological thymoma types A and B3 exhibit distinct genetic phenotypes, whereas type B3 thymoma and primary thymic squamous cell carcinoma partially share genetic aberrations. In addition to the possible tumorigenic role, the deletion in type B3 thymoma of chromosome 6, harboring the HLA locus, might play a role in the pathogenesis of paraneoplastic autoimmunity characteristic of thymoma.

Prenatal diagnosis of partial trisomy 4q26-qter and monosomy for the Wolf-Hirschhorn critical region in a fetus with split hand malformation

We describe the results of prenatal analyses and postnatal findings in a male fetus with a partial trisomy for the long arm and a small terminal monosomy for the short arm of chromosome 4 with the following karyotype: 46,XY,add(4)(p16.3).ish dup(4)(q26qter)(wcp4+, D4S2336x3,AFMb280xa5x2,4ptel-,WHCR-). G-banding did not identify the origin of the additional chromosomal segment, but this was achieved prenatally by application of RxFISH and whole chromosome painting probes. Subsequent FISH analysis with region-specific YAC clones was used to relate the phenotypic findings such as bilateral split hand formation, specific cardiac and kidney anomalies, microtia, and hypoplastic thorax more exactly to the partial trisomy of the segment 4q26-qter.