Maternal apo E genotype is a modifier of the Smith-Lemli-Opitz syndrome

BACKGROUND

Smith-Lemli-Opitz syndrome (MIM 270400) is an autosomal recessive malformation and mental retardation syndrome that ranges in clinical severity from minimal dysmorphism and mild mental retardation to severe congenital anomalies and intrauterine death. Smith-Lemli-Opitz syndrome is caused by mutations in the Delta7 sterol-reductase gene (DHCR7; EC 1.3.1.21), which impair endogenous cholesterol biosynthesis and make the growing embryo dependent on exogenous (maternal) sources of cholesterol. We have investigated whether apolipoprotein E, a major component of the cholesterol transport system in human beings, is a modifier of the clinical severity of Smith-Lemli-Opitz syndrome.

METHOD

Common apo E, DHCR7, and LDLR genotypes were determined in 137 biochemically characterised patients with Smith-Lemli-Opitz syndrome and 59 of their parents.

RESULTS

There was a significant correlation between patients' clinical severity scores and maternal apo E genotypes (p = 0.028) but not between severity scores and patients' or paternal apo E genotypes. In line with their effects on serum cholesterol levels, the maternal apo epsilon2 genotypes were associated with a severe Smith-Lemli-Opitz syndrome phenotype, whereas apo E genotypes without the epsilon2 allele were associated with a milder phenotype. The correlation of maternal apo E genotype with disease severity persisted after stratification for DHCR7 genotype. There was no association of Smith-Lemli-Opitz syndrome severity with LDLR gene variation.

CONCLUSIONS

These results suggest that the efficiency of cholesterol transport from the mother to the embryo is affected by the maternal apo E genotype and extend the role of apo E and its disease associations to modulation of embryonic development and malformations.

The use of remifentanil for intubation in paediatric patients during sevoflurane anaesthesia guided by Bispectral Index (BIS) monitoring

We studied the intubating conditions, haemodynamic and endocrine changes following tracheal intubation during sevoflurane anaesthesia guided by Bispectral Index (BIS) monitoring in 40 children who received either remifentanil 1 microg.kg-1 (group R) or saline 1 ml.kg-1 (group S). Acceptable intubating conditions were found in all patients in group R (n = 20), compared to only 12 patients in group S (p = 0.002). There were no intergroup differences in heart rate, systolic blood pressure and plasma concentrations of epinephrine and norepinephrine at any time point and changes in haemodynamic variables throughout the study period were moderate. Titration of sevoflurane delivery to a target BIS of 35 +/- 5 led to almost equal end-tidal sevoflurane concentrations in either group and remifentanil did not affect the BIS. There were no side-effects in either group that required intervention. Intubating conditions during sevoflurane anaesthesia in children were found to be improved by a single bolus dose of remifentanil 1 microg.kg-1.

Diffractive optical elements as raster-image generators

The use of diffractive optical elements (DOEs) to generate complex raster images for a primarily artistic purpose is dealt with. Aspects of human vision that are relevant for the design of such elements are discussed. A design method based on an iterative Fourier transform algorithm and extended with elements from the direct-binary-search and the simulated-annealing algorithms is described. The proposed method provides a large set of parameters that can be adjusted freely to optimize it for any given design task. For demonstration a phase-only DOE was designed that generates an image of a Chinese dragon as a diffraction pattern. It was realized as a surface-relief element on a planar substrate through multilevel binary lithography and reactive-ion etching. Experimental tests confirm the usefulness of the design and the fabrication procedures to achieve excellent image quality.

Development of an outcome/variance tracking tool for sedation and non-surgical procedures

A large academic cancer center devised a performance improvement plan for special procedures and sedation. A group of interdisciplinary professionals convened to address data collection, complications, and outcomes for non-surgical procedures and sedation. Administrative, medical, and nursing representatives from all areas in which these procedures are performed gathered to assess existing data and data collection methods and to develop an improvement plan. Gastroenterology, pulmonary, diagnostic imaging, intensive care, gynecology, genitourinary, hematology, and anesthesiology specialties were represented. The group was facilitated by staff from the institution's Office of Performance Improvement and co-chaired by an anesthesiologist and a pulmonary specialist. A representative from the Practice Outcomes Department was also an active participant. This article describes group process, design efforts, pilot testing, and analyses for this project. Pilot data are presented as well as a discussion of staff involvement.

Precise and simple optical alignment method for double-sided lithography

A method for aligning a photolithographic mask at the top of a transparent wafer that has a pattern on its bottom side is presented. The method is based on optical self-imaging of special alignment marks and provides submicrometer accuracy. The method is simple and robust and can conveniently be implemented on laboratory mask aligners for contact or proximity printing.

Novel diode laser-compatible fluorophores and their application to single molecule detection, protein labeling and fluorescence resonance energy transfer immunoassay

We describe a series of new long-wave absorbing and fluorescing cyanine dyes and labels (based on a general logic for the design of such dyes), their spectra, covalent and noncovalent linkage to proteins, their use in single molecule detection (SMD) and as donors and acceptors, respectively, in fluorescence resonance energy transfer studies. The new labels represent water-soluble and reactive fluorophores whose quantum yields increase substantially if noncovalently or covalently bound to proteins. Due to their strong absorptions between 550 and 700 nm they are excitable by light-emitting diodes or diode lasers. Their high absorbances (epsilon around 100,000) and adequate fluorescence quantum yields (phi up to 0.68 if bound to proteins) along with their availability as reactive NHS esters make them viable labels for proteins and oligomers, e.g. in context with SMD or fluorescence energy transfer immunoassay which is demonstrated for the system HSA/anti-HSA.

Phase quantization of a grating without altering the diffraction pattern

Quantization of the phase-delay profile of a diffractive optical element often leads to unwanted deviations of considerable extent in the diffraction pattern. A method for avoiding this flaw for periodic phase gratings is described. The idea is to forgo strict periodicity and use the new degrees of freedom thus obtained to compensate for quantization-related deviations. The method is demonstrated for Fourier-array illuminator gratings designed with an iterative Fourier-transform algorithm.

Practical realization of massively parallel fiber-free-space optical interconnects

We propose a novel approach to realizing massively parallel optical interconnects based on commercially available multifiber ribbons with MT-type connectors and custom-designed planar-integrated free-space components. It combines the advantages of fiber optics, that is, a long range and convenient and flexible installation, with those of (planar-integrated) free-space optics, that is, a wide range of implementable functions and a high potential for integration and parallelization. For the interface between fibers and free-space optical systems a low-cost practical solution is presented. It consists of using a metal connector plate that was manufactured on a computer-controlled milling machine. Channel densities are of the order of 100/mm(2) between optoelectronic VLSI chips and the free-space optical systems and 1/mm(2) between the free-space optical systems and MT-type fiber connectors. Experiments in combination with specially designed planar-integrated test systems prove that multiple one-to-one and one-to-many interconnects can be established with not more than 10% uniformity error.

Littoral cell angioma of the spleen: CT and MR imaging appearance

We report a case of littoral cell angioma (LCA) of the spleen, a recently described splenic pathology, which imaging characteristics and pathologic morphology have been discussed only by a few authors. The imaging findings in unenhanced and contrast-enhanced MRI and CT as well as histologic specimen are presented. Diagnosis was made after elective splenectomy. Differential diagnosis of splenic tumors as well as the imaging findings in this particular case are discussed.

Dynamic cardiocirculatory control during propofol anesthesia in mechanically ventilated patients

We evaluated dynamic cardiovascular control by spectral analytical methods in 20 young adults anesthetized with propofol (2.5 mg/kg, followed by continuous infusion of 0.1 mg/kg/min) and in an awake control group during cyclic stimulation of the carotid baroreceptors via sinusoidal neck suction at 0.2 Hz (baroreflex response mediated mainly by vagal activity) and at 0.1 Hz (baroreflex response mediated by vagal and sympathetic activity). During anesthesia and mechanical ventilation at 0.25 Hz, major underdampened hemodynamic oscillations occurred at 0.055 +/- 0.012 Hz. The response of RR intervals to baroreceptor stimulation at 0.2 Hz was markedly decreased during anesthesia (median of transfer function magnitude between neck suction and RR intervals 3% of the awake control). Blood pressure response to baroreceptor stimulation at 0.1 Hz was significantly decreased during anesthesia to 26% (systolic blood pressure), and 44% (diastolic blood pressure) of the awake control. There was a significant delay in baroreflex effector responses during anesthesia. Our results demonstrate a markedly depressed vagally mediated heart rate response and an impaired blood pressure response to cyclic baroreceptor stimulation during propofol anesthesia in mechanically ventilated patients. The disturbed baroreflex control is accompanied by an irregular dynamic behavior of cardiovascular regulation, indicating a decreased stability of the control system.

IMPLICATIONS

An irregular dynamic behavior of the cardiovascular control system, associated with an impaired baroreflex control of heart rate and blood pressure, can be observed during propofol anesthesia in mechanically ventilated subjects.

Planar-integrated optical vector-matrix multiplier

We present the design of a planar-integrated optoelectronic vector-matrix multiplier. The inherent parallel-processing potential is fully exploited by optical implementation of multiplications and summations. Planar integration makes the free-space optical system compatible with electronic VLSI technologies. It is composed of phase-only diffractive optical elements, which implement lens and multiple-beam-splitter functions. A demonstrator version of the optical system for a matrix of size 10 x 10 was fabricated on quartz glass by means of multimask lithography and reactive ion etching. It shows low cross talk and good uniformity of the signals.

A cytogenetic study on the teaching staff of a polluted school with a questionable increased incidence of malignancies

Exposure to pollutants, in particular polychlorinated biphenyls (PCB), was established at a school built in 1966. Because of a statistically conspicuous increased frequency of breast cancer observed in the teachers of the school this study was performed to ascertain whether the teachers in the polluted school have an increased level of micronucleated cells (MN) or sister chromatid exchanges (SCE) as an expression of a raised cytogenetic risk. Teachers in a directly adjacent school served as one control group and those from a school about 30 km away as a second one. Each teacher had to answer a questionnaire and after venous blood samples had been taken, the number of MN and SCE in peripheral lymphocytes were determined. For the teachers in the polluted school, in addition, the length of stay in the building during the last month and year was recorded. Thereby no correlation with the number of MN and SCE was proven. In comparison with the two control groups, neither the number of MN nor SCE was increased in the teachers of the polluted school. Even if their predictive value for cancer risk assessment is disputed, MN and SCE have a high rating as standard procedures in the proof of an exposure to genotoxic agents. This study thus does not provide any evidence that, for the teachers in the polluted school, a relevant exposure to genotoxic agents exists.

Architecture of the replication fork stalled at the 3' end of yeast ribosomal genes

Every unit of the rRNA gene cluster of Saccharomyces cerevisiae contains a unique site, termed the replication fork barrier (RFB), where progressing replication forks are stalled in a polar manner. In this work, we determined the positions of the nascent strands at the RFB at nucleotide resolution. Within an HpaI-HindIII fragment essential for the RFB, a major and two closely spaced minor arrest sites were found. In the majority of molecules, the stalled lagging strand was completely processed and the discontinuously synthesized nascent lagging strand was extended three bases farther than the continuously synthesized leading strand. A model explaining these findings is presented. Our analysis included for the first time the use of T4 endonuclease VII, an enzyme recognizing branched DNA molecules. This enzyme cleaved predominantly in the newly synthesized homologous arms, thereby specifically releasing the leading arm.

Pharmacokinetics of human cerebral opioid extraction: a comparative study on sufentanil, fentanyl, and alfentanil in a patient after severe head injury

BACKGROUND

The pharmacodynamic differences in time to onset and dissipation of effect of sufentanil, fentanyl, and alfentanil probably result from different rates of blood-brain equilibration. The authors investigated this hypothesis in humans.

METHODS

After simultaneous central venous bolus application of sufentanil (10 microg), fentanyl (100 microg), and alfentanil (1,000 microg), arterial and jugular bulb blood samples were drawn simultaneously at 20, 30, 45, 60, 75, 90, 105, 120, 140, 160, 180, 210, 240, 300, 360, and 420 s from 19 patients during the postacute stage of head injury with normal intracranial pressure, cerebral perfusion pressure, and cerebral oxygen metabolism during normocapnia.

RESULTS

Peak brain concentration, indicated by equilibrium between arterial and jugular bulb opioid concentrations, was achieved for alfentanil at 45 s, for sufentanil at 5 min, and for fentanyl at 6 min. The corresponding median time intervals (fifth and ninety-fifth percentiles) to reach 50% of peak brain concentration were 15 (14-18), 25 (18-38) and 35 (25-45) s, respectively. Uptake was highest 20 s after bolus and decreased continuously for fentanyl and sufentanil, whereas alfentanil uptake was biphasic. The ratio of the relative amounts of sufentanil, fentanyl, and alfentanil retained in the brain at peak brain concentration was 1x:x6x:x90.

CONCLUSIONS

The differences in the time lag between changes in serum concentrations and drug effect after bolus application of nearly equipotent doses of sufentanil, fentanyl, and alfentanil originate from the different times required to reach blood-brain equilibration, mainly depending on different levels and different time profiles of arterial blood concentrations caused by the different tissue distribution volumes.

Macrophage colony-stimulating factor antagonists inhibit replication of HIV-1 in human macrophages

Macrophages infected with HIV-1 produce high levels of M-CSF and macrophage-inflammatory protein-1alpha (MIP-1alpha). M-CSF facilitates the growth and differentiation of macrophages, while the chemotactic properties of MIP-1alpha attract both T lymphocytes and macrophages to the site of HIV infection. Studies described in this work indicate M-CSF may function in an autocrine/paracrine manner to sustain HIV replication, and data suggest possible therapeutic strategies for decreasing viral load following HIV infection. We show that macrophage infection with measles virus or respiratory syncytial virus, in contrast to HIV-1, results in production of MIP-1alpha, but not M-CSF. Thus, M-CSF appears to be specifically produced upon infection of macrophages with HIV-1. Furthermore, addition of M-CSF antagonists to HIV-1-infected macrophages, including anti-M-CSF monoclonal or polyclonal Abs or soluble M-CSF receptors, dramatically inhibited HIV-1 replication and reduced production of MIP-1alpha. Our results suggest that biologic antagonists for M-CSF may represent novel strategies for inhibiting the spread of HIV-1 by 1) blocking virus replication in macrophages, 2) reducing recruitment of HIV-susceptible T cells and macrophages by MIP-1alpha, and 3) preventing the establishment and maintenance of infected macrophages as a reservoir for HIV.

Compound A does not accumulate during closed circuit sevoflurane anaesthesia with the Physioflex

We have investigated inspiratory and end-tidal gas composition during sevoflurane anaesthesia in a closed circle system with continuous gas flow (70 litre min-1, Physioflex) to determine possible accumulation of sevoflurane degradation products. During five abdominal operations in adults lasting more than 2 h, anaesthesia was maintained with an end-tidal concentration of 2% sevoflurane in 40% oxygen-air. The circle included an absorbing canister filled with 1 litre of fresh soda lime. Samples were obtained at the end of an expiration from the tracheal tube and from the inspiratory limb before, and at selected times after, addition of sevoflurane. The temperature of soda lime was 24.7 +/- 0.7 degrees C at the beginning and reached a maximum of 31.2 +/- 1.0 degrees C after 20-30 min, followed by a plateau. Inspiratory compound A (CH2F-O-C(= CF2)(CF3)) 3-8 ppm was detected after 10 min, but did not accumulate in the circle over 2 h without flushing. Expired concentrations were consistently lower with 1.5-3 ppm signalling absorption by patients. Calculated total amounts absorbed over 2 h varied between 2.0 and 7.2 ppm h. Other degradation products such as compound B or methanol were not detected. In summary, we did not detect sevoflurane metabolites with soda lime in significant amounts during closed circle anaesthesia with the Physioflex. The observed concentrations of compound A were below the threshold of nephrotoxicity in rats by a factor of more than 20.

Elimination of methohexitone after long-term, high-dose infusion in patients with critically elevated intracranial pressure

OBJECTIVE

To determine the plasma elimination of methohexitone in patients with critically elevated intracranial pressure (ICP) who received the drug in high doses for several days.

DESIGN

Drug-monitoring study.

SETTING

Intensive care unit at a university hospital.

PATIENTS

Twelve intensive care unit patients with brain injuries who received methohexitone as a final therapeutic approach after routine therapy had proved to be insufficient in controlling critically elevated ICP.

MEASUREMENTS AND MAIN RESULTS

Plasma samples were taken during methohexitone infusion, before cessation, and in distinct, short increments after discontinuation of the infusion. Methohexitone was determined in plasma by reverse-phase high-pressure liquid chromatography and photometric detection. The median duration of infusion of methohexitone was 137 hrs (minimum, 27 hrs; maximum, 445 hrs), with a median infusion rate of 62.5 microg/kg/min (minimum, 22.5 microg/kg/min; maximum, 116.2 microg/kg/min). Plasma concentrations of methohexitone at burst suppression under concomitant analgesic sedation ranged from 1.6 to 17.3 microg/mL (median, 4.7 microg/mL). After cessation of methohexitone infusion, the decline of plasma concentrations followed a biexponential function. Clearance rates, volume of distribution at steady state, context-sensitive half-time, and initial and terminal elimination half-times were calculated. Pharmacokinetic data showed remarkable interindividual variability that could not be correlated to the infusion rate, to the duration of the infusion, or to obvious differences in physiology or the disease states of these patients. Even in patients with high plasma concentrations who received the drug for a considerable length of time, the initial decline in plasma concentration was exponential, indicating redistribution.

CONCLUSIONS

We conclude that the elimination kinetics of methohexitone after long-term, high-dose infusion in critically ill patients with brain injuries may favor the use of methohexitone over thiopentone for controlling critically elevated ICP by allowing for a more timely neurologic examination after cessation.

Characterization of a novel model of pancreatic fibrosis and acinar atrophy

Significant fibrosis and acinar atrophy are characteristics of chronic pancreatitis; however, because of the lack of a reproducible model, early phases of these changes are poorly understood. We have developed a model of severe hyperstimulation and obstruction pancreatitis (SHOP) to better define the mechanisms of early pancreatic fibrogenesis. Sprague-Dawley rats were used and SHOP was induced by complete pancreatic duct obstruction and daily cerulein hyperstimulation (50 microg/kg intraperitoneally). Animals were killed at 24, 48, 72, and 96 hours. Control animals underwent sham operation and received no cerulein. Pancreata were prepared for hematoxylin and eosin and sirius red (collagen-specific) staining and for hydroxyproline assay (measure of total collagen content). We found moderate amounts of edema and inflammation but minimal parenchymal necrosis. Significant loss of acinar cell mass was noted by 48 hours, and normal acinar cells were essentially absent by 96 hours. Tissue collagen content increased with time and large amounts of interstitial collagen were detected by 72 hours. In conclusion, SHOP is a novel model of early pancreatic fibrosis associated with minimal necrosis and a significant decrease in acinar cell mass, making it an ideal model to study the early cellular mechanisms of pancreatic fibrogenesis.

Dry soda lime markedly degrades sevoflurane during simulated inhalation induction

We have investigated gas composition during simulated inhalation induction with sevoflurane to elucidate possible mechanisms of incidental prolonged induction times and airway irritation. Using a circle system, 8% sevoflurane in oxygen 6 litre min-1 was washed into an absorbing canister filled with fresh soda lime containing 2.9% KOH (Draegersorb, 'D') or no KOH (< 0.01%, Sofnolime, 'S'). The absorbent was dried by oxygen 20,000 litre before every second experiment. Maximum soda lime temperatures attained after 4-6 min were 107 degrees C using dry D and 62 degrees C (61 degrees C) with dry S. Temperature did not increase with fresh soda lime. With dry soda lime, sevoflurane was not detected at the T-piece for 3 min and reached 6-7% within 6-10 min. After 1 min, we detected methanol and compound A (CH2F-O-C(= CF2) (CF3)). Total amounts over 20 min were: methanol 1125 mg (D dry), 334 mg (S dry) and < 5 mg (fresh soda lime); compound A 148 mg (D dry), 13 mg (S dry) and 3-8 mg (fresh); and fluoride 8.5 mg (D dry), 3.3 mg (S dry) and 1 mg (fresh). Formaldehyde was detected only with dry lime (D > 2.5 mg, S > 0.6 mg). In summary, the use of moist soda lime is of crucial importance during inhalation induction. With dry soda lime, the patient may inhale potentially toxic degradation products in significant amounts. Sevoflurane degradation is aggravated by a high KOH content of the lime. The observed airway irritation may be caused by formic acid, which is generated in isomolar concentrations with methanol (Cannizzaro reaction). The amount of compound A found with dry KOH-containing lime is unlikely to be noxious.

Sister chromatid exchange in human lymphocytes exposed to isoflurane and nitrous oxide in vitro

The question of whether or not inhalation anaesthetics are genotoxic remains controversial. Therefore, we have studied the in vitro genotoxic potential of isoflurane and nitrous oxide in human lymphocytes. Blood samples were obtained from eight healthy male, non-smoking volunteers, which were incubated and exposed to increasing concentrations of isoflurane (0.0, 0.3, 0.6 and 1.2 mmol litre-1) or 50% nitrous oxide in oxygen. Baseline sister chromatid exchange (SCE) rate per cell was mean 7.65 (SD 1.5) which increased to 9.15 (1.0), 9.55 (1.4) and 9.95 (1.8) SCE/cell during exposure to isoflurane 0.3, 0.6 and 1.2 mmol litre-1, respectively. During 50% nitrous oxide exposure, SCE rate was 9.26 (1.4). The difference between the control and exposed cells was statistically significant (P < or = 0.05). We conclude that exposure to nitrous oxide and subanaesthetic concentrations of isoflurane can produce genetic damage in peripheral lymphocytes in vitro.

Protein binding of piritramide: influence of various protein concentrations and the postoperative acute phase response

OBJECTIVE

Piritramide is a lipophilic opioid, which is widely used for postoperative analgesia and analgosedation in Europe. In this study we investigated the influence of various protein concentrations (total protein, alpha1-acid glycoprotein, albumin) and the postoperative acute phase response on the protein binding of piritramide.

METHODS

The influence of various protein concentrations on the protein binding of piritramide was investigated by either diluting the serum samples of five volunteers with isotonic saline or by adding different amounts of alpha1-acid glycoprotein. Albumin binding was measured in a 5% human albumin solution. The impact of the postoperative acute phase response was investigated by obtaining daily serum samples from 18 surgical patients until the third postoperative day, and measuring piritramide protein binding, alpha1-acid glycoprotein, total protein and albumin.

RESULTS

There was a significant relationship between piritramide protein binding and the concentrations of total protein and alpha1-acid glycoprotein. The binding to albumin was 88%. During the postoperative acute phase response, the protein binding of piritramide did not change. Serum concentrations of alpha1-acid glycoprotein increased, whereas total protein and albumin decreased.

CONCLUSION

Although there were significant changes in the piritramide-binding proteins, alpha1-acid glycoprotein and albumin, during the postoperative acute phase response, the protein binding of piritramide did not change. Therefore, a change in protein binding, which might be one factor to be considered in determining piritramide dosage in the postoperative period, does not have to be taken into account.