Quantitative Field Emission Imaging for Studying the Doping-Dependent Emission Behavior of Silicon Field Emitter Arrays

Field emitter arrays (FEAs) are a promising component for novel vacuum micro- and nanoelectronic devices, such as microwave power amplifiers or fast-switching X-ray sources. However, the interrelated mechanisms responsible for FEA degradation and failure are not fully understood. Therefore, we present a measurement method for quantitative observation of individual emission sites during integral operation using a low-cost, commercially available CMOS imaging sensor. The emission and degradation behavior of three differently doped FEAs is investigated in current-regulated operation. The measurements reveal that the limited current of the p-doped emitters leads to an activation of up to 55% of the individual tips in the array, while the activation of the n-type FEA stopped at around 30%. This enhanced activation results in a more continuous and uniform current distribution for the p-type FEA. An analysis of the individual emitter characteristics before and after a constant current measurement provides novel perspectives on degradation behavior. A burn-in process that trims the emitting tips to an integral current-specific ideal field enhancement factor is observed. In this process, blunt tips are sharpened while sharp tips are dulled, resulting in homogenization within the FEA. The methodology is described in detail, making it easily adaptable for other groups to apply in the further development of promising FEAs.

Ustekinumab Inhibits T Follicular Helper Cell Differentiation in Patients With Crohn's Disease

BACKGROUND & AIMS

The pathogenesis of chronic inflammatory bowel diseases (Crohn's disease [CD] and ulcerative colitis) involves dysregulated TH1 and TH17 cell responses, which can be targeted therapeutically by the monoclonal antibody Ustekinumab directed against the joint p40 subunit of IL-12 and IL-23. These cytokines may also regulate the differentiation of T follicular helper (TFH) cells, which promote B cell function in germinal centers. However, the role of TFH cells in CD pathogenesis and impact of Ustekinumab therapy on TFH cell fate in patients are poorly defined.

METHODS

Lymphocytes were isolated from peripheral blood (n=45) and intestinal biopsies (n=15) of CD patients or healthy controls (n=21) and analyzed by flow cytometry to assess TFH cell phenotypes and functions ex vivo. In addition, TFH cell differentiation was analyzed in the presence of Ustekinumab in vitro.

RESULTS

TFH cell frequencies in the intestine as well as peripheral blood were associated with endoscopic as well as biochemical evidence of CD activity. CD patients with clinical response to Ustekinumab, but not those with response to anti-TNF antibodies, displayed reduced frequencies of circulating TFH cells in a concentration-dependent manner while the TFH phenotype was not affected by Ustekinumab therapy. In keeping with this notion, TFH cell differentiation was inhibited by Ustekinumab in vitro while TFH cell maintenance was not affected. Moreover, Ustekinumab therapy resulted in reduced germinal center activity in CD patients in vivo.

CONCLUSIONS

These data implicate TFH cells in the pathogenesis of CD and indicate that Ustekinumab therapy affects TFH cell differentiation, which may influence TFH-mediated immune functions in UST-treated CD patients.

Ustekinumab serum concentrations are associated with clinical outcomes in Crohn's disease - a regional multi-center pilot study

BACKGROUND AND AIM

 The role of therapeutic drug monitoring (TDM) in ustekinumab (UST) therapy for Crohn's disease (CD) has not been established, as only few studies have analyzed the relationship between UST serum concentrations and clinical outcome. In this pilot study, we retrospectively examined the potential of UST-concentrations (cUST) 8 weeks after induction (cUSTw8) to predict clinical response at week 16.

METHODS

 Serum samples and clinical data from patients (n = 72) with moderate to severely active CD who received intravenous induction with UST were retrospectively analyzed. cUST were quantitated using liquid chromatography-tandem mass spectrometry (LC-MSMS). A receiver-operating characteristic (ROC) curve and area under ROC curve (AUROC) was computed to analyze the predictive potential of cUSTw8 for clinical response at week 16 and to determine the minimal therapeutic UST trough concentration.

RESULTS

 Forty-four patients (61 %) achieved clinical response to UST therapy at week 16. cUSTw8 was moderately effective to predict clinical response with a minimal therapeutic cUSTw8 of 2.0 mg/l (AUC 0.72, p = 0.001).

CONCLUSION

 Trough concentrations of UST 8 weeks after induction predict clinical response to therapy in week 16 with moderate sensitivity and specificity. TDM using LC-MSMS could prove beneficial in personalized UST therapy of patients with CD by identifying individuals with subtherapeutic concentrations who might benefit from dose escalation.

Detecting Anti-IIa and Anti-Xa Direct Oral Anticoagulant (DOAC) Agents in Urine using a DOAC Dipstick

The assessment of the anticoagulant effect of direct oral anticoagulants (DOACs) can be important for rapid medical decision-making, especially in patients needing immediate management. An assay that screens for the absence or presence of a DOAC would help accelerate treatment in these situations. Chromogenic and coagulation methods have several limitations, including limited accuracy, long turnaround time, and their need of specialized laboratories. Oral factor Xa and thrombin inhibitors are also eliminated by the kidneys and can be detected in patient urine samples using a single, rapid, sensitive, and patient-specific qualitative assay. In these tests, the presence or absence of a DOAC in urine can be identified by visually observing specific colors after a few minutes. Several studies have demonstrated the robustness and repeatability of these assays. The specific colors of the test strip also detect creatinine in the urine, which shows whether DOAC excretion is reduced, thus suggesting renal impairment. Persons with amblyopia may use a specific reader. Current indications for using the DOAC Dipstick test include emergency medical situations with severe bleeding and thrombotic events or before urgent major surgical interventions to accelerate medical decision-making.

High vitamin D3 diet administered during active colitis negatively affects bone metabolism in an adoptive T cell transfer model

Decreased bone mineral density (BMD) represents an extraintestinal complication of inflammatory bowel disease (IBD). Vitamin D₃ has been considered a viable adjunctive therapy in IBD. However, vitamin D₃ plays a pleiotropic role in bone modeling and regulates the bone formation-resorption balance, depending on the physiological environment, and supplementation during active IBD may have unintended consequences. We evaluated the effects of vitamin D₃ supplementation during the active phase of disease on colonic inflammation, BMD, and bone metabolism in an adoptive IL-10-/- CD4⁺ T cell transfer model of chronic colitis. High-dose vitamin D₃ supplementation for 12 days during established disease had negligible effects on mucosal inflammation. Plasma vitamin D₃ metabolites correlated with diet, but not disease, status. Colitis significantly reduced BMD. High-dose vitamin D₃ supplementation did not affect cortical bone but led to a further deterioration of trabecular bone morphology. In mice fed a high vitamin D₃ diet, colitis more severely impacted bone formation markers (osteocalcin and bone alkaline phosphatase) and increased bone resorption markers, ratio of receptor activator of NF-κB ligand to osteoprotegrin transcript, plasma osteoprotegrin level, and the osteoclast activation marker tartrate-resistant acid phosphatase (ACp5). Bone vitamin D receptor expression was increased in mice with chronic colitis, especially in the high vitamin D₃ group. Our data suggest that vitamin D₃, at a dose that does not improve inflammation, has no beneficial effects on bone metabolism and density during active colitis or may adversely affect BMD and bone turnover. These observations should be taken into consideration in the planning of further clinical studies with high-dose vitamin D₃ supplementation in patients with active IBD.

Electron spectrometer in adjustable triode configuration for photo-induced field emission measurements

We have constructed a new ultrahigh vacuum apparatus with a triode configuration for the systematic investigation of photo-induced field emission (PFE) from metallic or semiconducting cathodes. These are exposed to electric fields up to 400 MV∕m and laser irradiation by means of hole or mesh gates. Cathodes and gates are in situ exchangeable and adjustable with high precision to ensure a homogeneous extraction of electrons which are partially transmitted to the fixed electron spectrometer. Its hemispherical sector analyzer provides an energy resolution limit of 8 meV. The commissioning of the measurement system has been performed with a tungsten needle. Its temperature showed up in the high-energy tail of the electron spectrum, while its work function was derived from the spectral low-energy part combined with the integral current-voltage curve. First PFE measurements on B-doped Si-tip arrays yielded a small field emission current increase under green laser illumination. A shift and splitting of the energy spectra was observed which revealed different emission regimes as well as the photosensitivity of the cathode due to carrier excitation into the conduction band. For the full exploitation of the PFE system, a tunable laser over a wide eV-range is required.

Comparison of cryopreservation methods on T-cell responses to islet and control antigens from type 1 diabetic patients and controls

BACKGROUND

Type 1 diabetes (T1D) is a cell-mediated autoimmune disease characterized by destruction of the pancreatic islet cells. The use of cryopreserved cells is preferable to the use of freshly isolated cells to monitor clinical trials to decrease assay and laboratory variability.

METHODS

The T-Cell Workshop Committee of the Immunology of Diabetes Society compared two widely accepted T-cell freezing protocols (warm and cold) to freshly isolated peripheral blood mononuclear cells from patients with T1D and controls in terms of recovery, viability, cell subset composition, and performance in functional assays currently in use in T1D-related research. Nine laboratories participated in the study with four different functional assays included.

RESULTS

The cold freezing method yielded higher recovery and viability compared with the warm freezing method. Irrespective of freezing protocol, B cells and CD8+ T cells were enriched, monocyte fraction decreased, and islet antigen-reactive responses were lower in frozen versus fresh cells. However, these results need to take in to account that the overall response to islet autoantigens was low in some assays.

CONCLUSIONS

In the current study, none of the tested T-cell functional assays performed well using frozen samples. More research is required to identify a freezing method and a T-cell functional assay that will produce responses in patients with T1D comparable to responses using fresh peripheral blood mononuclear cells.

Agomelatine improves sleep in a patient with fatal familial insomnia

A young patient with FFI was started on agomelatine 25 mg to medicate nocturnal insomnia. Under this treatment sleep efficiency was improved, slow wave sleep was high and awakenings during sleep period time were far less than before. Clinically the patient was less restless during nighttime.

Absolute testing of the reference surface of a Fizeau interferometer through even/odd decompositions

Absolute testing of spherical surfaces is a technological necessity because of increased accuracy requirements. In a Fizeau setup, the main part of the interferometer deviations thereby comes from the reference surface. We demonstrate the validity of an absolute testing procedure for the reference surface that has been proposed earlier. The procedure relies on the decomposition of the surface deviations into odd and even parts and could be used in partially coherent illumination. The odd deviations are obtained from a basic and a 180 degree-rotated position of an auxiliary sphere, and the even deviations can be measured with the help of a cat's eye position in double pass using an opaque half screen in the interferometer aperture.

Detection of Recent Ethanol Intake With New Markers: Comparison of Fatty Acid Ethyl Esters in Serum and of Ethyl Glucuronide and the Ratio of 5-Hydroxytryptophol to 5-Hydroxyindole Acetic Acid in Urine

BACKGROUND

At present, recent ethanol consumption can be routinely detected with certainty only by direct measurement of ethanol concentration in blood or urine. Because ethanol is rapidly eliminated from the circulation, however, the time span for this detection is in the range of hours. Several new markers have been proposed to extend the detection interval, but their characteristics have not yet justified their use in routine clinical practice. We therefore investigated three new markers and compared their kinetics and sensitivities: (1) fatty acid ethyl esters (FAEEs) in serum, (2) ethyl glucuronide (EtG) in urine, and (3) the ratio of 5-hydroxytryptophol to 5-hydroxyindole acetic acid (5-HTOL/5-HIAA) in urine.

METHODS

Seventeen healthy men participated in a drinking experiment. Blood and urine samples were collected twice daily on three consecutive days and once daily on days 4 and 5. Ethanol concentration was determined by gas chromatography, FAEE levels, by gas chromatography with mass spectrometry, EtG concentration, by liquid chromatography-tandem mass spectrometry, and 5-HTOL/5-HIAA ratio, by high-performance liquid chromatography.

RESULTS

The peak serum ethanol concentrations of the subjects ranged from 5.4 to 44.7 mmol/liter (mean +/- SD, 30.1 +/- 9.1 mmol/liter). In the case of the serum ethanol determination, 100% sensitivity was reached only immediately after the end of the drinking experiment, and in the case of FAEE levels and 5-HTOL/5-HIAA ratio, it tested for 6.7 hr after the end of the ethanol intake. Thereafter, these latter parameters declined until 15.3 hr (FAEEs) and 29.4 hr (5-HTOL/5-HIAA), subsequently remaining in a stable range until 78.5 hr without further decrease. In contrast, EtG concentration showed 100% sensitivity until 39.3 hr and thereafter decreased, falling to below the limit of quantification of 0.1 mg/liter at 102.5 hr.

CONCLUSION

After moderate drinking, EtG in the urine proved to be a superior marker of recent ethanol consumption in healthy subjects. This is because EtG is a direct ethanol metabolite, it occurs in the urine only when ethanol has been consumed, and its sensitivity remains at the level of 100% for 39.3 hr.

Reversible segmental cerebral vasoconstriction (Call-Fleming syndrome): are calcium channel inhibitors a potential treatment option?

The Call-Fleming syndrome is characterized by sudden onset of thunderclap-like headache and focal neurological deficits. The pathophysiological correlate is a reversible segmental cerebral vasoconstriction frequently associated with focal cerebral ischaemia. The syndrome has been described in a variety of clinical conditions, and recently an association between the syndrome and exposure to vasoactive drugs was observed. Effective treatment options are not known. A 63-year-old female developed sudden 'worst ever' headache. Initial neurological examination, laboratory blood tests, CSF examination and brain magnetic resonance imaging (MRI) were normal. Previous medical history was unremarkable and she did not take vasoactive drugs. Eleven days after the onset of headache she developed visual field impairment and a right-sided hemiparesis. Brain MRI revealed bilateral posterior and left parietal ischaemic strokes. Cerebral catheter angiography showed segmental arterial vasoconstriction. A vasodilative therapy with calcium channel inhibitors was started and serial transcranial Doppler ultrasonography demonstrated resolution of cerebral arterial vasoconstriction. The present case illustrates that calcium channel inhibitors may be an effective therapy for segmental cerebral arterial vasoconstriction. However, more clinical data are needed to prove this observation.

[Isolated intracerebral cystic echinococcosis. Unusual presentation of a rare disease]

HISTORY AND CLINICAL FINDINGS

A 46-year-old woman was admitted with a first generalised tonic-clonic seizure. Past medical history was unremarkable. She reported no travels abroad within the past five years.

INVESTIGATIONS

Brain MRI demonstrated disseminated cerebral and cerebellar focal lesions. Cerebrospinal fluid analysis showed a mild eosinophilic pleocytosis. Extensive imaging investigations and serological tests revealed no hints for a systemic parasitic disease. A stereotactic brain biopsy detected no pathogenic agent. 10 months following the initial admission, brain MRI showed multiple cystic lesions with ring-like enhancement following Gd-DTPA administration. At that time serological tests were positive for an infection with Echinococcus granulosus.

DIAGNOSIS

The diagnosis was based on positive sequential serological tests and the typical MRI findings in conjunction with an eosinophilic cerebrospinal fluid pleocytosis.

TREATMENT AND CLINICAL COURSE

An antihelmintic therapy with Albendazole was initiated. Following two-months of oral Albendazole administration, brain MRI revealed a clear reduction in size and number of the hydatid lesions. The patient was free of complaints and the clinical examination was unremarkable.

CONCLUSION

Isolated intracerebral manifestation of cystic echinococcosis is very rare. Compared to the typical presentation with a solitary cerebral hydatid cyst, the dissemination of hydatid cysts is quite uncommon in cystic echinococcosis. Diagnosis should be based on the typical MRI findings and serological tests. The present case demonstrates that the later may be negative over a long period within the clinical course of the disease offering a real challenge to the clinician.

Clinical bond failure of pre-coated and operator-coated orthodontic brackets

OBJECTIVES

To test the hypothesis that there is no significant difference in clinical bracket failure between the 3M APC Mini Twin bracket system and the Transbond XT adhesive during orthodontic treatment.

DESIGN

A randomized, split mouth, prospective clinical trial.

SETTING AND SAMPLE POPULATION

The Department of Orthodontics and Dentofacial Orthopedics at University of Missouri, Kansas City. Twenty-nine subjects who were treatment planned to receive comprehensive orthodontics using 0.018 slot appliances.

EXPERIMENTAL VARIABLE

The adhesive pre-coated brackets (APC) system was randomly assigned to one side of the mouth and the Transbond XT was assigned to the opposite side.

OUTCOME MEASURE

The absence of any of the brackets at the time of a regular or emergency orthodontic appointment.

RESULTS

There was no significant difference (P > 0.05) in bracket failure between the 3M APC Mini Twin bracket system and the Transbond XT adhesive at any time period (90, 180, or 365 days). The failure rate of brackets on premolars was higher than on incisors or canines.

CONCLUSION

APC Mini Twin bracket system and Transbond XT adhesive are equally effective in maintaining brackets clinically. Inexperienced operators had an overall 7.5% bond failure 12 months following bracket placement.

γ-COP, a coat subunit of non-clathrin-coated vesicles with homology to Sec21p

Constitutive secretory transport in eukaryotes is likely to be mediated by non-clathrin-coated vesicles, which have been isolated and characterized [(1989) Cell 58, 329-336; (1991) Nature 349, 215-220]. They contain a set of coat proteins (COPs) which are also likely to exist in a preformed cytosolic complex named coatomer [(1991) Nature 349, 248-250]. From peptide sequence and cDNA structure comparisons evidence is presented that one of the subunits of coatomer, gamma-COP, is a true constituent of non-clathrin-coated vesicles, and that gamma-COP is related to sec 21, a secretory mutant of the yeast Saccharomyces cervisiae.

Sleep and sleep-wake cycle in an 81-year-old patient with de novo ultra-rapid cycling bipolar disorder

This is a case report of an 81-year-old man who developed de novo bipolar disorder with ultrarapid cycling at the age of 80. Mood was self-rated daily over a period of ten weeks; in addition, polysomnographic and motor activity recordings were performed during a drug-free baseline period. Both depressive and hypomanic episodes had an average duration of about 30 hours; the affective cycle was thus independent from the sleep-wake cycle. When mood shifts occurred during nighttime, sleep was different in nights following depression than in nights following hypomania. Positron emission tomography revealed a moderate bilateral frontal hypermetabolism in the hypomanic phase and yielded normal findings for the depressive stage. In contrast to what is usually expected in ultra-rapid cycling bipolar disorder, this case demonstrates an unusual sleep-unrelated cycle duration in the oldest reported patient so far.

[Kufs-disease; a rare cause of early-onset dementia]

The case of a 35-year-old man with progressive dementia from the age of 17 is presented. Clinical examination showed mild extrapyramidal and cerebellar signs and rare myoclonus. Neuropsychological evaluation disclosed severe cognitive deficits. Magnetic resonance imaging (MRI) revealed moderate generalized atrophy with abnormal iron deposition in the basal ganglia. Positron emission tomography (PET) with 18-fluorodeoxyglucose (18-FDG) demonstrated clear temporoparietal hypometabolism. The clinical symptoms and course are typical for the rare adult type of neuronal ceroid lipofuscinoses (Kufs' disease). The diagnosis is supported by the electron microscope detection of an abnormal accumulation of lipid vacuoles and lipofuscin in the eccrine sweat glands and the rectal ganglia cells.

Differential effects of sevoflurane, isoflurane, and halothane on Ca2+ release from the sarcoplasmic reticulum of skeletal muscle

BACKGROUND

Although malignant hyperthermia after application of sevoflurane has been reported, little is known about its action on intracellular calcium homeostasis of skeletal muscle. The authors compared the effect of sevoflurane with that of isoflurane and halothane on Ca2+ release of mammalian sarcoplasmic reticulum and applied a novel method to quantify Ca2+ turnover in permeabilized skeletal muscle fibers.

METHODS

Liquid sevoflurane, isoflurane, and halothane at 0.6 mM, 3.5 mM, and 7.6 mm were diluted either in weakly calcium buffered solutions with no added Ca2+ (to monitor Ca2+ release) or in strongly Ca2+ buffered solutions with [Ca2+] values between 3 nM and 24.9 microm for [Ca+]-force relations. Measurements were taken on single saponin skinned muscle fiber preparations of BALB/c mice. Individual [Ca2+]force relations were characterized by the Ca2+ concentration at half-maximal force that indicates the sensitivity of the contractile proteins and by the steepness. Each force transient was transformed directly into a Ca2+ transient with respect to the individual [Ca2+]-force relation of the fiber.

RESULTS

At 0.6 mM, single force transients induced by sevoflurane were lower compared with equimolar concentrations of isoflurane and halothane (P < 0.05). Similarly, calculated peak Ca2+ transients of sevoflurane were lower than those induced by equimolar halothane (P < 0.05). The Ca2+ concentrations at half maximal force were decreased after the addition of sevoflurane, isoflurane, and halothane in a concentration-dependent manner (P < 0.05).

CONCLUSION

Whereas sevoflurane, isoflurane, and halothane similarly increase the Ca2+ sensitivity of the contractile apparatus in skeletal muscle fibers, 0.6 mM sevoflurane induces smaller Ca2+ releases from the sarcoplasmic reticulum than does equimolar halothane.

Testing of rod objects by grazing-incidence interferometry: experiment

A grazing-incidence interferometer for the testing of technical surfaces for macroscopic surface deviations is described. Computer-generated holograms serve as beam splitters and references for the workpieces tested. The sensitivity of the interferometer depends on the period of the computer-generated holograms. The method is demonstrated at a rod object of convex profile. Using phase-stepping techniques, the grazing-incidence interferometer provides fast measurements of the entire mantle surface of the test sample with submicrometer precision.

Axicon-type test interferometer for cylindrical surfaces: systematic error assessment

The principle and the alignment aberration functions are described for an axicon-type test interferometer for measuring cylindrical mantle surfaces. Additionally, we show that the derived systematic alignment functions fulfill for reasonably small misalignments the requirements for measurements in the range of approximately 1/100 of a fringe. We verify this with optical path-length calculations, using ray tracing.

Molecular cloning of human phosphomevalonate kinase and identification of a consensus peroxisomal targeting sequence

Two overlapping cDNAs which encode human liver phosphomevalonate kinase (PMKase) were isolated. The human PMKase cDNAs predict a 191-amino acid protein with a molecular weight of 21,862, consistent with previous reports for mammalian PMKase (Mr = 21,000-22,500). Further verification of the clones was obtained by expression of PMKase activity in bacteria using a composite 1024-base pair cDNA clone. Northern blot analysis of several human tissues revealed a doublet of transcripts at approximately 1 kilobase (kb) in heart, liver, skeletal muscle, kidney, and pancreas and lower but detectable transcript levels in brain, placenta, and lung. Analysis of transcripts from human lymphoblasts subcultured in lipid-depleted sera (LDS) and LDS supplemented with lovastatin indicated that PMKase gene expression is subject to regulation by sterol at the level of transcription. Southern blotting indicated that PMKase is a single copy gene covering less than 15 kb in the human genome. The human PMKase amino acid sequence contains a consensus peroxisomal targeting sequence (PTS-1), Ser-Arg-Leu, at the C terminus of the protein. This is the first report of a cholesterol biosynthetic protein which contains a consensus PTS-1, providing further evidence for the concept that early cholesterol and nonsterol isoprenoid biosynthesis may occur in the peroxisome.

VIP21/caveolin is a cholesterol-binding protein

VIP21/caveolin is localized to both caveolae and apical transport vesicles and presumably cycles between the cell surface and the Golgi complex. We have studied the lipid interactions of this protein by reconstituting Escherichia coli-expressed VIP21/caveolin into liposomes. Surprisingly, the protein reconstituted only with cholesterol-containing lipid mixtures. We demonstrated that the protein binds at least 1 mol of cholesterol per mole of protein and that this binding promotes formation of protein oligomers. These findings suggest that VIP21/caveolin, through its cholesterol-binding properties, serves a specific function in microdomain formation during membrane trafficking.

Novel N-glycosylation in eukaryotes: laminin contains the linkage unit beta-glucosylasparagine

The linkage unit to protein of N-linked carbohydrate in eukaryotic glycoproteins consists of N-acetylglucosamine, coupled to the amido nitrogen of asparagine. Additional N-glycosyl linkage units have been unequivocally proven to exist only in the cell surface glycoproteins of various bacteria. Based on immunological analyses, isolation and chemical characterization, we report that one of these units, namely glucose linked to asparagine, exists in the mammalian protein laminin, an extracellular basement membrane component. This finding and the occurrence of identical disaccharide structures in archaebacterial cell surface glycoproteins and mammalian basement membrane protein complexes points towards a conserved and distinct function of these extracellular structural elements. In addition, a method is described to uncover a masked epitope in fixed tissues by chemical O-deglycosylation. This has allowed to morphologically localize the antigen beta-Glc-Asn by immunofluorescence to the basement membranes of kidney glomeruli.

Primary structure of the heterosaccharide of the surface glycoprotein of Methanothermus fervidus

The outer surface of the cells of the hyperthermophile Methanothermus fervidus is covered by crystalline glycoprotein subunits (S-layer). From the purified S-layer glycoprotein, a heterosaccharide was isolated. The heterosaccharide consists of D-3-O-methylmannose, D-mannose, and D-N-acetylgalactosamine in a molar ratio of 2:3:1 corresponding to a relative molecular mass of 1061.83 Da. 3-O-methylmannose could be partly replaced by 3-O-methylglucose. The primary structure of the glycan was revealed by methylation analysis, by plasma desorption mass spectrometry, and by high field NMR spectroscopy. The purified heterosaccharide is linked via N-acetylgalactosamine to an asparagine residue of the peptide moiety. The following structure is proposed for the heterosaccharide: alpha-D-3-O-MetManp-(1-->6)-alpha-D-3-O-MetManp-((1-->2)-alp ha-D-Manp)3-(1-->4) - D-GalNAc.

Identification of a new missense mutation in Japanese phenylketonuric patients

A new missense mutation in the phenylalanine hydroxylase (PAH) gene was identified in 20/30 members of the families of 10 unrelated Japanese phenylketonuria (PKU) patients from Kyushu island. The point mutation was present in 20 of 40 mutant alleles. This was proved by DNA sequence analysis after polymerase chain reaction (PCR) amplification and allele-specific oligonucleotide (ASO) hybridization. This point mutation, an A to G transition at the first base of codon 276 in exon 7, resulted in an amino acid substitution. Methionine was replaced by valine and the mutation was found to be associated with restriction fragment length polymorphism (RFLP) haplotype 4 in the investigated patients. The mutation was not found in 24 unrelated Caucasian patients from different countries. These findings may indicate a founder effect in the transmission of the mutation.

Transcranial magnetic stimulation (TMS) of the brain in patients with mesiotemporal epileptic foci

Transcranial magnetic stimulation (TMS) of the human brain is mainly used for the diagnosis of diseases with disturbed central motor conduction. Recent studies revealed controversial results concerning the possibility of a TMS-induced specific activation of epileptogenic foci in patients with localization-related epilepsies, which would make TMS an additional diagnostic tool for the presurgical localization of the primary epileptogenic zone. We applied TMS to 19 patients with complex-partial seizures and investigated its effects and safety. In 12 patients we performed TMS during scalp electroencephalogram (EEG) recordings. The remaining 7 patients with localization-related epilepsies of mesiobasal limbic seizure origin underwent EEG with additionally implanted foramen-ovale-electrodes (FOE). We did not notice any significant spike activation and even observed bilateral reduction of epileptic activity in some patients. On the contrary, hyperventilation induced a marked activation of the epileptic focus. Our findings support that TMS is safe since adverse effects did not occur. However, due to possible safety hazards, TMS in epileptic patients still requires cautious application until more data will be available.

Heterozygous fragile X female: historical, physical, cognitive, and cytogenetic features

Historical, physical, cognitive, and cytogenetic data were documented in 105 heterozygous fragile X [fra(X)] females and 90 controls in a prospective fashion. For comparisons, we divided heterozygotes and controls into those with cognitive impairment (IQ less than 85) and normal IQ (IQ greater than or equal to 85). The only finding that was significantly more frequent in impaired heterozygotes compared with impaired controls chi 2 analysis was shyness. Features that were more frequent in normal IQ heterozygotes compared with normal controls were voluntary thumb dislocation and hyperextensible metacarpal-phalangeal (MP) joints. Comparisons among heterozygotes demonstrated more math problems, hand biting, strabismus, high-arched palate, hyperextensible finger joints, and flat feet in impaired heterozygotes than in normal heterozygotes. Premature menopause was present in 8 of 61 normal heterozygotes and in none of the impaired heterozygotes. A multiple regression analysis demonstrated a significant inverse correlation between the percent fragility and IQ for the heterozygotes as a group. However, no correlation existed between IQ and fragility when the percent fragility was 2% or greater. However, a higher percentage of fragility was positively correlated with the total number of physical findings present.

Developmental implications of changing trajectories of IQ in males with fragile X syndrome

This study examined the trajectories of cognitive development in boys under the age of 21 years with fragile X syndrome. By combining information from three centers, data from 66 boys were analyzed; only children who had been tested two or more times with the same psychometric instrument at one or more year intervals were included in this study. Results demonstrated that males with fragile X syndrome show a decline in IQ scores, with the most marked declines seen during the early pubertal period. All 22 children retested during the 11- to 15-year period showed IQ declines, suggesting a slowing of development associated with the onset of puberty. Before age 10 years, males with higher (as opposed to lower) pretest IQs were more likely to decline at subsequent testings. A single etiological factor may not be sufficient to account for the observed findings, as both changes in neurobiological- and task-related factors seem implicated in the slowing intellectual development of this population.

Long-term follow-up after surgical management of necrotizing enterocolitis: sixty-three cases

One hundred twenty-five infants underwent surgical intervention for necrotizing enterocolitis between 1972 and 1984. Sixty-three infants, who survived more than 30 days postoperatively, were evaluated for long-term complications. There were 28 girls and 35 boys (mean birth weight 1,725 +/- 890 g; gestational age 32 +/- 4 weeks). Associated problems included hyaline membrane disease (43), cardiac anomalies (25), and trisomy 21(2). Thirty-six survivors required long-term ventilatory support. Fifty-nine infants underwent bowel resection and enterostomy, 3 decompressing enterostomies without resection, and 1, exploratory laparotomy only. Enterostomies were closed at four months. Twenty four had short bowel syndrome. Fifteen infants subsequently died for a late mortality rate of 23%. Mortality was related to sepsis (3), respiratory failure (5), cardiac anomalies (3), cardio-respiratory arrest (2), and TPN related liver failure (2), and was common with gestational age less than 31 weeks and birth weight less than 1,000 g. Medical problems included cholestasis (17), TPN induced cirrhosis (3), meningitis (3), seizures (8), and nutritional rickets (6). Significant developmental and intellectual delays were observed.

Neonatal intracranial hemorrhage and complicating hydrocephalus

Real-time ultrasound studies of the head were performed on 96 infants weighing 1500 g or less. This population represented all such infants admitted within the first 72 hours of life to a neonatal intensive care unit over a 9-month period. Intracranial subependymal/intraventricular hemorrhage occurred in 22 (23%) of the infants. Of these 13 (59%) developed ventricular enlargement. Four other infants, in whom hemorrhage was not identified, also developed ventricular enlargement. When it occurred, the ventricular enlargement developed within 2 weeks of the hemorrhage in 77% of cases. It reached its maximum size within 2 weeks in 65% of cases. In 9 of 16 cases the maximal ventricular enlargement was categorized as mild. Spontaneous arrest or resolution of the ventriculomegaly occurred in all but two cases, who required shunting. Clot resolution was slow. It was complete at 3 weeks in only 5 of 18 cases.

Evaluation of the gasless abdomen in the newborn and young infant with metrizamide

The finding of a gasless abdomen on the abdominal radiograph of an infant over 12 hr old is usually abnormal and may reflect a serious pathologic disorder. Accurate diagnosis is important to plan appropriate therapy. A careful review of the clinical history and the plain chest and abdominal radiographs will often permit an accurate diagnosis to be made. In cases where the diagnosis remains in doubt, contrast studies of the bowel with metrizamide have proved helpful. This report presents six infants with gasless abdomens of unknown cause. In each case, a metrizamide contrast study of the bowel was helpful in providing an accurate diagnosis.

A new look at the neonatal bowel-contrast studies with metrizamide (Amipaque)

Metrizamide is the first water-soluble radiographic contrast agent which, because it is nonionic, can be used in isotonic solution and gives good visualization of the desired body structure. Its only major disadvantage is that it is very expensive. Metrizamide can be used to study the neonatal bowel in clinical situations where all the other existing contrast agents are contraindicated. The results of 55 metrizamide studies of the bowel in infants are reviewed. In necrotizing enterocolitis metrizamide aids in confirming or rejecting the diagnosis, identifying patients for surgery, and in evaluating the response to surgery. Metrizamide can identify the etiology in unusual cases of bowel obstruction. Metrizamide correctly identified a thoracic origin of free peritoneal air in four cases and a bowel origin in two cases. It identified bowel perforation in two patients in the absence of pneumoperitoneum. In six patients, the metrizamide study identified the cause for a gasless abdomen. It is concluded that metrizamide has a valuable role to play in evaluating a variety of neonatal bowel disorders.

Therapeutic neuromuscular paralysis in neonates: characteristic radiographic features

Neonates with respiratory distress requiring mechanical ventilation may be treated with muscular paralysis to improve oxygenation. This results in characteristic radiographic features that relate in part to the specific drug used. The radiographic signs are: bell-shaped chest, decreased bowel gas, and soft-tissue edema. When all three findings are present, the use of neuromuscular blockade can be suggested from the radiographs alone without the aid of clinical history. Radiographs of 57 infants treated with muscular paralysis and mechanical ventilation were compared to 20 infants treated with mechanical ventilation alone. In paralyzed patients, a characteristic bell-shaped chest was seen in 24 of 57 and decreased bowel gas in 46 of 52. Soft-tissue edema was seen in patients treated with metocurine, and the incidence increased with duration of therapy (18 of 25 treated for 5 or more days); it was not radiographically detected in patients treated with d-tubocurarine (0 of 13). Bell-shaped chest, decreased bowel gas, and soft-tissue edema occurred one, three, and one times, respectively, in 20 nonparalyzed control infants, and each time the findings carried significantly different clinical implications. All cases were reviewed to determine if pulmonary edema can result from mobilization of soft-tissue edema fluid after cessation of neuromuscular paralysis, and this was found not to occur.

Neonatal pneumoperitoneum without significant adventitious pulmonary air: use of metrizamide to rule out perforation of the bowel

Pneumoperitoneum in the neonate may be due to air that has dissected from the chest. Four infants, in whom pneumoperitoneum, from thoracic air dissection, occurred in the absence of pneumothorax or pneumomediastinum are reported. The absence of abnormal collections of air in the chest is of no value in deciding whether a pneumoperitoneum is due to bowel perforation or air dissecting from the chest. Contrast bowel studies are needed in all cases of pneumoperitoneum in the infant to distinguish bowel perforation from intrathoracic origin of the air.

Mediation of retinal photoisomerization by adduct formation with tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)-europium(II)

Several retinal isomers are shown to form adducts in isooctane solution with a lanthanide beta-diketonate complex, tris(6,6,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III) [Eu(fod)3]. The adducts are characterized by an absorption band whose lambda max at approximately 420 nm is red-shifted by approximately 60 nm from the lowest-energy absorption band in the free retinal isomers. Irradiation into this adduct band leads to photoisomerization. For example, photolysis of a 1 mM all-trans-retinal/3 mM Eu(fod)3 isooctane solution at 514.5 nm leads, with reasonable quantum efficiency (phi greater than or equal to 0.05), to isomeric mixtures that are considerably different from these produced with UV excitation in the absence of Eu(fod)3. Particularly noteworthy for a photolysis conducted in a nonpolar solvent is the presence of an appreciable quantity of 11-cis-retinal in the adduct photolysate.

The use of metrizamide (amipaque) to visualise the gastrointestinal tract in children: a preliminary report

Metrizamide (amipaque) has not been used previously as a diagnostic contrast agent in the gastrointestinal tract. Metrizamide is a water-soluble isotonic contrast material having many advantages over barium and existing hypertonic water-soluble agents. There are many clinical situations in children in which metrizamide should be the contrast agent of choice for investigating the gastrointestinal tract. Four neonates are presented in whom barium or gastrografin were absolutely contraindicated. In each case metrizamide gave excellent visualization of the gastrointestinal tract. It could be followed through be bowel giving excellent visualisation even up to 120 h after ingestion. No harmful effects were noted in the four cases studied.

Use and abuse of oxygen in the newborn

Hypoxia must be prevented in the newborn. It causes atelectasis, acidosis and pulmonary vasoconstriction, which leads to further hypoxia and, ultimately, brain damage. On the other hand, retrolental fibroplasia and bronchopulmonary dysplasia may result from too-vigorous use of oxygen therapy. Frequent blood gas measurements are required. Administered oxygen must be humidified and heated, and the oxygen concentration must be monitored with each delivery system. It is not enough to know the oxygen flow rate; an oxygen analyzer is essential.

Conception and construction of a teaching simulator (umbilical vessel catheterization)

Difficult medical procedures, such as umbilical vessel catheterization, are more easily and safely taught with a simulator than with the actual patient. The need, conception, design, and construction of such a simulator is presented in the hope that others may recognize its value and be encouraged to design their own teaching simulators for their particular needs.