Rapid and Simple Buffer Exchange Using Cation-Exchange Chromatography to Improve Point-of-Care Detection of Pharmacological Agents

The current COVID-19 pandemic has highlighted the power, speed, and simplicity of point-of-care (POC) diagnostics. POC diagnostics are available for a wide range of targets, including both drugs of abuse as well as performance-enhancing drugs. For pharmacological monitoring, minimally invasive fluids such as urine and saliva are commonly sampled. However, false positives or negatives caused by interfering agents excreted in these matrices may confound results. For example, false positives have, in most cases, prevented the use of POC diagnostics for pharmacological agent detection; the consequence is that centralized labs are instead tasked to perform these screenings, resulting in significant delays between sampling and testing. Thus, a rapid, simple, and inexpensive methodology for sample purification is required for the POC to reach a field-deployable tool for the pharmacological human health and performance assessments. Buffer exchange is a simple, rapid approach to remove interfering agents, but has traditionally been difficult to perform on small pharmacological molecules. Therefore, in this communication, we use salbutamol, a performance-enhancing drug, as a case example to demonstrate the efficacy of ion-exchange chromatography as a technique to perform buffer exchange for charged pharmacological agents. This manuscript demonstrates the efficacy of this technique leveraging a commercial spin column to remove interfering agents found in simulant urines, such as proteins, creatinine, and urea, while retaining salbutamol. The utility and efficacy of the method was then confirmed in actual saliva samples. The eluent was then collected and run on the lateral flow assays (LFAs), improving the reported limit of detection by over 5× (new lower limit of detection of 10 ppb compared to reported 60 ppb by the manufacturer) while simultaneously removing noise due to background interfering agents.

Blood calcium concentration and performance in periparturient and early lactating dairy cows is influenced by plant bioactive lipid compounds

Previous studies ex vivo suggested that plant bioactive lipid compounds (PBLC) can increase ruminal calcium absorption. Therefore, we hypothesized that PBLC feeding around calving may potentially counteract hypocalcemia and support performance in postpartum dairy cows. The corresponding aim of the study was to investigate the effect of PBLC feeding on blood minerals in Brown Swiss (BS) and hypocalcemia-susceptible Holstein Friesian (HF) cows during the period from d -2 to 28 relative to calving and on milk performance until d 80 of lactation. A total of 29 BS cows and 41 HF cows were divided each into a control (CON) and PBLC treatment group. The latter was supplemented with 1.7 g/d menthol-rich PBLC from 8 d before expected calving to 80 d postpartum. Milk yield and composition, body condition score and blood minerals were measured. Feeding PBLC induced a significant breed × treatment interaction for iCa, supporting that PBLC increased iCa exclusively in HF cows; the increase was 0.03 mM over the whole period and 0.05 mM from d 1 to 3 after calving. Subclinical hypocalcemia was seen in one BS-CON and 8 HF-CON cows and 2 BS-PBLC and 4 HF-PBLC cows. Clinical milk fever was detected only in HF cows (2 HF-CON and one HF-PBLC). Other tested blood minerals, such as sodium, chloride, and potassium, as well as blood glucose, were neither affected by PBLC feeding nor breed, nor were their 2-way interactions, except for higher sodium levels in PBLC cows on d 21. Body condition score showed no effect of treatment, except for a lower body condition score in BS-PBLC compared with BS-CON at d 14. Dietary PBLC increased milk yield, milk fat yield, and milk protein yield at 2 consecutive dairy herd improvement test days. As indicated by treatment × day interactions, energy-corrected milk yield and milk lactose yield were increased by PBLC on the first test day only, and milk protein concentration decreased from test d 1 to test d 2 in CON only. The concentrations of fat, lactose, and urea, as well as somatic cell count, were not affected by treatment. The weekly milk yield over the first 11 wk of lactation was 29.5 kg/wk higher for PBLC versus CON across breeds. It is concluded that the applied PBLC induced a small but measurable improvement of calcium status in HF cows in the study period and had additional positive effects on milk performance in both breeds.

In Silico Assessment of Acute Oral Toxicity for Mixtures

While exposure of humans to environmental hazards often occurs with complex chemical mixtures, the majority of existing toxicity data are for single compounds. The Globally Harmonized System of chemical classification (GHS) developed by the Organization for Economic Cooperation and Development uses the additivity formula for acute oral toxicity classification of mixtures, which is based on the acute toxicity estimate of individual ingredients. We evaluated the prediction of GHS category classifications for mixtures using toxicological data collected in the Integrated Chemical Environment (ICE) developed by the National Toxicology Program (United States Department of Health and Human Services). The ICE database contains in vivo acute oral toxicity data for ∼10,000 chemicals and for 582 mixtures with one or multiple active ingredients. By using the available experimental data for individual ingredients, we were able to calculate a GHS category for only half of the mixtures. To expand a set of components with acute oral toxicity data, we used the Collaborative Acute Toxicity Modeling Suite (CATMoS) implemented in the Open Structure-Activity/Property Relationship App to make predictions for active ingredients without available experimental data. As a result, we were able to make predictions for 503 mixtures/formulations with 72% accuracy for the GHS classification. For 186 mixtures with two or more active ingredients, the accuracy rate was 76%. The structure-based analysis of the misclassified mixtures did not reveal any specific structural features associated with the mispredictions. Our results demonstrate that CATMoS together with an additivity formula can be used to predict the GHS category for chemical mixtures.

Effects of prostaglandin E2 on cells cultured from the rat organum vasculosum laminae terminalis and median preoptic nucleus

The time course of the induction of enzymes responsible for the formation of prostaglandin E2 (PGE2) after an inflammatory insult, in relation to the concomitant febrile response, suggests that peripherally generated PGE2 is involved in the induction of the early phase of fever, while centrally produced PGE2 exerts pyrogenic capacities during the later stages of fever within the hypothalamic median preoptic nucleus (MnPO). The actions of peripherally derived PGE2 on the brain might occur at the level of the organum vasculosum laminae terminalis (OVLT), which lacks a tight blood-brain barrier and is implicated in fever, while the effects of PGE2 within the MnPO might interfere with glutamatergic neurotransmission within a recently characterized central efferent pathway for the activation of cold-defence reactions. Using the fura-2 ratio imaging technique we, therefore, measured changes of the intracellular Ca(2+)-concentration in primary neuroglial microcultures of rat OVLT and MnPO stimulated with PGE2 and/or glutamate. In cultures from the OVLT, as opposed to those derived from the MnPO, substantial numbers of neurons (8% of 385), astrocytes (19% of 645) and microglial cells (28% of 43) directly responded to PGE2 with a transient increase of intracellular Ca(2+). The most pronounced effect of PGE2 on cells from MnPO microcultures was its modulatory influence on the strength of glutamate-induced Ca(2+)-signals. In 72 out of 512 neurons and in 105 out of 715 astrocytes PGE2 significantly augmented glutamate-induced Ca(2+)-signals. About 30% of these neurons were GABAergic. These observations are in agreement with putative roles of peripheral PGE2 as a directly acting circulating agent at the level of the OVLT, and of central MnPO-intrinsic PGE2 as an enhancer of glutamatergic neurotransmission, which causes disinhibition of thermogenic heat production, a crucial component for the manifestation of fever. In microcultures from both brain sites investigated incubation with PGE2 significantly reduced the lipopolysaccharide-induced release of cytokines (tumor necrosis factor-α and interleukin-6) into the supernatant. PGE2, thus, seems to be involved in a negative feed-back loop to limit the strength of the brain inflammatory process and to play a dual role with pro- as well as anti-inflammatory properties.

Fundamental mode operation of a ribbon fiber laser by way of volume Bragg gratings

Selection of the fundamental mode of an active large mode area "ribbon" fiber laser with core dimensions of 107.8 μm by 8.3 μm was produced by a transmitting Bragg grating (TBG) in a free-space resonator. The multimode performance of the original laser was characterized to have an M2 of 11.3 with an absorbed power slope efficiency of 76%. With the TBG aligned to provide maximum diffraction efficiency for the fundamental mode, the M2 improved to 1.45 at an absorbed power slope efficiency of 54% and enhanced the brightness by 5.1 times.

Comparison of high-volume air sampling equipment for viral aerosol sampling during emergency response

OBJECTIVE

This study compared the performance of two high-volume bioaerosol air samplers for viable virus to an accepted standard low-volume sampler. In typical bioaerosol emergency response scenarios, highvolume sampling is essential for the low infective concentrations and large air volumes involved.

DESIGN

Two high-volume air samplers (XMX/2LMIL and DFU-1000) were evaluated alongside a lowvolume sample (BioSampler). Low and high concentrations (9.3-93.2 agent containing particles per liter of air [ACPLA]) of male-specific coliphage 2 (MS2) virus were released into a 12 m3 aerosol test chamber and collected using the air samplers. The collection media from the samplers were then processed and viable virus was assessed via plaque assay.

SETTING

Aerosol test chamber.

SUBJECTS, PARTICIPANTS

None.

INTERVENTIONS

Collection media and flow rate were modified for the XMX/2L-MIL sampler for viable analysis.

MAIN OUTCOME MEASURES

Concentration estimates in units of plaque forming units per liter of air (PFU/liter) assessed by the samplers as compared to the levels inside the chamber as evaluated with a slit to agar plate in units of ACPLA. Comparison was made via one-way analysis of variance.

RESULTS

Both the XMX/2L-MIL and DFU-1000 achieved collection effectiveness equal to or greater than the low-volume air sampler for the evaluated MS2 concentrations. The XMX/2L-MIL reliably collected quantifiable low concentrations of MS2, but the DFU-1000 was unable to do so.

CONCLUSIONS

For emergency response to suspected bioaerosols, the evaluated high-volume samplers are as effective as the standard low-flow sampler and should be considered in conducting a health risk assessment. If low concentrations are expected, then high-flow samplers using liquid collection are preferred.

Beryllium surface levels in a military ammunition plant

This study evaluated the presence of beryllium surface contamination in a U.S. conventional munitions plant as an indicator of possible past beryllium airborne and skin exposure and used these measurements to classify job categories by potential level of exposure. Surface samples were collected from production and nonproduction areas of the plant and at regional industrial reference sites with no known history of beryllium use. Surface samples of premoistened wiping material were analyzed for beryllium mass content using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and results expressed as micrograms of beryllium per 100 square centimeters (micro g/100 cm(2)). Beryllium was detected in 87% of samples collected at the munitions plant and in 72% of the samples collected at regional reference sites. Two munitions plant samples from areas near sanders and grinders were above 3.0 micro g/100 cm(2) (U.S. Department of Energy surface contamination limit). The highest surface level found at the reference sites was 0.44 micro g/100 cm(2). Workers in areas where beryllium-containing alloy tools were sanded or ground, but not other work areas, may have been exposed to airborne beryllium concentrations above levels encountered in other industries where metal work is conducted. Surface sampling provided information useful for categorizing munitions plant jobs by level of past beryllium airborne and skin exposure and, subsequently, for identifying employees within exposure strata to be screened for beryllium sensitization.

Comparison of the Grimm 1.108 and 1.109 Portable Aerosol Spectrometer to the TSI 3321 Aerodynamic Particle Sizer for Dry Particles

This study compared the response of two optical particle counters with that of an aerodynamic particle sizer. The optical particle counters rely on the amount of incident light scattered at 90 degrees by a particle to measure particle number concentration by optical particle size. Two models of optical particle counters from Grimm Technologies were used: the portable aerosol spectrometer (PAS) 1.108 (0.3-20 microm in 15 channels); and the PAS 1.109 (0.2-20 microm in 30 size channels). With a substantially different operating principle from that employed by the optical particle counters, the aerodynamic particle sizer (APS) model 3321 (TSI, Inc., St Paul, MN, USA) sizes particles according to their behavior in an accelerating flow to provide particle number concentration by aerodynamic size over a slightly narrower size range (0.5-20 microm) in 52 channels. The responses of these instruments were compared for three sizes of monodisperse solid aerosols composed of polystyrene latex spheres and a polydisperse aerosol composed of Arizona test dust. The PASs provided similar results to those from the APS. However, there were systematic differences among instruments in number and mass concentration measurement that depended upon particle size.

Diminuer la dose en tomodensitométrie abdominale : baisser la tension (kV) ou la charge (mAs) ?

PURPOSE

To compare low-dose protocols using either reduction of the tension (kV) or reduction of the intensity (mAs) at abdominal CT imaging, with reference to image quality.

MATERIALS AND METHODS

Fifty adult patients, weighing less than 55 kg, were prospectively included among patients referred for abdominal CT examination when the protocol required a noncontrast study. The images obtained with the standard protocol (120 kV, 200 mAs) were compared to 4 additional test images, two obtained with low intensity (120 kV, 100 mAs) and two obtained with low tension (100 kV, 200 mAs). Two senior radiologists blindly reviewed all images using both subjective (itemized list) and objective criteria (measure of standard deviation for density measurements obtained of the liver parenchyma).

RESULTS

The image quality of the low kV protocol was better than the image quality of the low mAs protocol for both subjective and objective criteria.

CONCLUSION

For abdominal CT imaging of standard to thin adult patients or children, dose reduction using a low kV protocol may be an alternative to a protocol using a low intensity. This can easily be implemented and can be used in conjunction with a dose reducing software.

Analgesic efficacy of a single dose of lumiracoxib compared with rofecoxib, celecoxib and placebo in the treatment of post-operative dental pain

This randomised, double-blind, placebo-controlled, parallel-group study compared the efficacy and tolerability of lumiracoxib (a novel COX-2 selective inhibitor) with rofecoxib, celecoxib and placebo in patients with moderate-to-severe post-operative dental pain. Following third molar extraction, patients received single oral doses of lumiracoxib 400 mg, rofecoxib 50 mg, celecoxib 200 mg or placebo (n = 355). Additional patients from a similar study, assigned to lumiracoxib, rofecoxib or placebo (n = 155), were included for analysis of the primary variable, Summed Pain Intensity Difference over the first 8 h post dose (SPID-8). For SPID-8, lumiracoxib was superior to rofecoxib (p < 0.05), celecoxib (p < 0.001) and placebo (p < 0.001). Lumiracoxib demonstrated the fastest onset of analgesia and the longest time to rescue medication use. Patient global evaluation of lumiracoxib was comparable to rofecoxib and superior to celecoxib and placebo. All treatments were well tolerated. Lumiracoxib 400 mg provides rapid, effective and sustained relief of post-operative dental pain, comparable or superior to rofecoxib.

[Cardiac pacing in West Africa: feasibility, problems, and perspectives]

BACKGROUND

The frequency of conductive trouble is not know in West-Africa where the evacuation to Europe and the cardiology institute of Abidjan has been for long time the only possibility to implant stimulators. We analyse our experience, the problems ant the perspectives.

METHODS

Over a three year period 92 patients (47 men, 45 women) were implanted using new (47%) or a recycled pacemaker. The technique used was essentially endoveinous (sub-clavicular puncture) except 2 children. The medium length of treatment was 24 months.

RESULTS

Syncope was noticed at the entrance in most 50% of cases. The degenerative etiology was dominant in 85%. Most cases (87%) used the VVI mode. Complications comprised 3 leads deplacements, 5 infections, 1 pacemaker syndrome and 1 death by mesenteria ischemia. Seven patients died later without any relation of cardiac pacing.

CONCLUSION

Despite an intrinsically high cost, pacemaker implantation is feasible and useful in selected indications in developing countries.

Discovery and characterization of non-competitive antagonists of group I metabotropic glutamate receptors

We have investigated the mechanism of inhibition of the new group I mGluR antagonists CPCCOEt and MPEP and determined that both compounds have a non-competitive mode of inhibition. Furthermore using chimeric/mutated receptors constructs we have found that these antagonists act at a novel pharmacological site located in the trans-membrane (TM). Specific non-conserved amino acid residues in the TM domain have been identified which are necessary for the inhibition by CPCCOEt and MPEP of the mGlul and mGlu5 receptors, respectively. Using molecular modeling a model of the TM domain was built for both mGlu1 and mGlu5 receptor subtypes. Docking of CPCCOEt and MPEP into their respective model allowed the modelisation of the novel binding site.

Inhibition of HIV-1 virion production by a transdominant mutant of integrase interactor 1

Integase interactor 1 (INI1), also known as hSNF5, is a protein that interacts with HIV-1 integrase. We report here that a cytoplasmically localized fragment of INI1 (S6; aa183-294) containing the minimal integrase-interaction domain potently inhibits HIV-1 particle production and replication. Mutations in S6 or integrase that disrupt integrase-INI1 interaction abrogated the inhibitory effect. An integrase-deficient HIV-1 transcomplemented with integrase fused to Vpr was not affected by S6. INI1 was specifically incorporated into virions and was required for efficient HIV-1 particle production. These results indicate that INI1 is required for late events in the viral life cycle, and that ectopic expression of S6 inhibits HIV-1 replication in a transdominant manner via its specific interaction with integrase within the context of Gag-Pol, providing a novel strategy to control HIV-1 replication.

Measures of psychopathology in children with complex partial seizures and primary generalized epilepsy with absence

OBJECTIVE

This investigation examined psychopathology in 48 children with complex partial seizures (CPS), 39 children with primary generalized epilepsy with absence (PGE), and 59 nonepileptic children, aged 5 to 16 years, by comparing the Child Behavior Checklist (CBCL) and the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS).

METHOD

The CBCL was completed by parents and the K-SADS was administered to both parent and child.

RESULTS

The CBCL identified psychopathology in 26% and the K-SADS in 51% of the CPS and PGE patients (kappa = 0.32). The CPS and PGE groups had significantly higher mean CBCL scores, as well as higher rates of psychiatric diagnoses and symptoms of psychopathology, compared with the nonepileptic group. However, the CPS and PGE groups did not differ in these measures. Within each patient group, Full Scale IQ, but not seizure control, was associated with these measures of psychopathology.

CONCLUSION

These findings suggest that the K-SADS identifies more children with psychopathology than the CBCL in children with CPS and PGE.

A human nuclear shuttling protein that interacts with human immunodeficiency virus type 1 matrix is packaged into virions

Active nuclear import of the human immunodeficiency virus type 1 (HIV-1) preintegration complex (PIC) is essential for the productive infection of nondividing cells. Nuclear import of the PIC is mediated by the HIV-1 matrix protein, which also plays several critical roles during viral entry and possibly during virion production facilitating the export of Pr55(Gag) and genomic RNA. Using a yeast two-hybrid screen, we identified a novel human virion-associated matrix-interacting protein (VAN) that is highly conserved in vertebrates and expressed in most human tissues. Its expression is upregulated upon activation of CD4(+) T cells. VAN is efficiently incorporated into HIV-1 virions and, like matrix, shuttles between the nucleus and cytoplasm. Furthermore, overexpression of VAN significantly inhibits HIV-1 replication in tissue culture. We propose that VAN regulates matrix nuclear localization and, by extension, both nuclear import of the PIC and export of Pr55(Gag) and viral genomic RNA during virion production. Our data suggest that this regulatory mechanism reflects a more global process for regulation of nucleocytoplasmic transport.

Chiral resolution, pharmacological characterization, and receptor docking of the noncompetitive mGlu1 receptor antagonist (+/-)-2-hydroxyimino- 1a, 2-dihydro-1H-7-oxacyclopropa[b]naphthalene-7a-carboxylic acid ethyl ester

Racemic CPCCOEt ((1aRS,7aRS)-2-hydroxyimino-1a, 2-dihydro-1H-7-oxacyclopropa[b]naphthalene-7a-carboxylic acid ethyl ester, (+/-)-1) derivatives have been shown to be subtype-selective metabotropic glutamate (mGlu) 1 receptor antagonists (Annoura et al. Bioorg. Med. Chem. Lett. 1996, 6, 763-766). The optical isomers of (+/-)-1 have been separated by chromatography on a chiral stationary phase. The absolute configuration at the C-1a and C-7a positions was determined using X-ray crystallography of an amide derivative with the methyl ester of L-phenylalanine (L-PheOMe) ((+)-6). In a phosphoinositol (PI) turnover assay at the cloned human mGlu1b receptor, (-)-1 and the new amide derivatives (-)-5 and (-)-6, all of which have (1aS,7aS)-stereochemistry on the chromane ring system, showed IC(50) values of 1.5, 0.43, and 0.93 microM, respectively. In contrast, (+)-1 and the new amide derivatives (+)-5 and (+)-6were found to be inactive up to a concentration of 30 microM indicating a selectivity for the (-)-enantiomers of at least 70-fold. In a previous study (Litschig et al. Mol. Pharmacol. 1999, 55, 453-461) we demonstrated using site-directed mutagenesis that the interaction site of (+/-)-1 is located in the transmembrane (TM) domain of hmGlu1b. To suggest a plausible binding mode of (-)-1, we have built a molecular mechanics model of the putative seven TM domain of hmGlu1 based on the alpha-carbon template of the TM helices of rhodopsin. A receptor docking hypothesis suggests that the OH of T815 (TMVII) comes in close contact with the oxime OH of (-)-1 and (-)-5, whereas no such close interactions could be demonstrated by docking of (+)-1.

The phenomenon of "picky eater": a behavioral marker in eating patterns of toddlers

OBJECTIVE

To determine if toddlers who were considered "picky eaters" had lower dietary scores than non-picky eaters, and if family environment and socioeconomic status were significantly related to picky eater status and dietary scores.

METHODS

An incomplete block design provided two interviews at randomly assigned times (24, 28, 32, or 36 months) of Caucasian mothers from upper socioeconomic (n=74) and lower socioeconomic status (n=44). Using trained interviewers, 6 days of food intake, two administrations of a questionnaire about toddler's eating behavior, and one administration of the Family Environment Scales were collected in the home. MANOVA, discriminant function analysis, and logistic regression procedures were used to determine significant differences between picky and non-picky eater groups.

RESULTS

Picky eaters had lower dietary variety (p=.03) and diversity scores (p=.009) than non-picky eaters. Mothers of picky eaters compared to those of non-picky eaters used persuasion (p=.0001) and ranked their child's eating behaviors as more problematic (p=.0001).

CONCLUSION

Toddlers perceived by their mothers as picky eaters had significantly lower dietary variety and diversity scores. Parents need information and strategies to increase the number of foods acceptable to their toddlers and to develop a sound feeding plan.

Incorporation of nitric oxide-releasing crosslinked polyethyleneimine microspheres into vascular grafts

Over the years, many attempts have been made to increase the patency of small- to medium-sized prosthetic vascular grafts. However, none of them has greatly affected long-term rates. Recently, nitric oxide (NO) has been shown to inhibit thrombus formation in such grafts, suggesting that local delivery of NO may help to increase graft patency. This study describes the site-specific delivery of NO by entrapping NO-releasing microspheres in the pores of a vascular graft. NO-releasing polyethyleneimine microspheres (PEIX) were developed using a novel water-in-oil emulsion technique involving chemical crosslinking with a bis-epoxide. The PEIX microspheres were then derivatized with NO forming the [N(O)NO]- moiety of the diazeniumdiolates formerly known as NONOates. These polymeric NO-releasing particles were found to spontaneously release 194 nmol NO/mg with a half-life of over 66 h under physiologic conditions. Fluorescein isothiocyanate-labeled microspheres were then embedded into the pores of a 60-micron nonreinforced Gore-tex vascular graft using a simple evacuation technique and evaluated for microsphere placement and NO release. Scanning electron microscopic analysis showed the microspheres entrapped in the pores of the vascular graft releasing 10 nmol NO/mg with a half-life of 51 h. The microspheres remained entrapped in the graft even after immersion and NO release, as confirmed by fluorescence of the medium. These results suggest that NO-releasing particles can be incorporated into the pores of a vascular graft to deliver therapeutic amounts of NO for the prevention of thrombosis in small-diameter prosthetic grafts.

Transitions in infant feeding during the first year of life

OBJECTIVE

To document ages at which transitions in infant feeding occur, to compare these transitions to literature reports from the 1970s and 80s, and to identify maternal characteristics related to the age of the infant when solid food was first introduced.

METHODS

Ninety-eight mother/infant pairs (middle and upper socioeconomic status) participated in the longitudinal study. Using a randomized, incomplete block design, in-home interviews were conducted by trained personnel when infants were 2, 3, 4, 6, 8, 10, and 12 months of age; each mother/infant pair was seen four or five times. Information on food intake, including breast milk/formula, was collected at each interview. Means +/- SD and frequencies were calculated, and least squares analysis of variance was used to develop a predictive model related to the introduction of cereal.

RESULTS

Most mothers decided on the initial feeding mode (breastfeeding or formula) prior to pregnancy; 83% breastfed initially although most (76%) totally discontinued breastfeeding by 6 months. Infants' ages varied greatly when each of the seven categories of food was introduced, cereal was added to the infants' diets at a mean age of 3.8 +/- 1.4 (SD) months, juice 4.7 +/- 2.2, fruit 4.9 +/- 1.6, vegetables 5.2 +/- 1.3, mixed foods 7.8 +/- 2.1, table foods 8.2 +/- 2.1, and meat 8.2 +/- 2.1. The multivariate model explained 59% of the variability in ages of infants when cereal (generally the first solid food) was added. Significant variables (p < or = 0.05) were feeding mode, recommendation by the physician, and the interaction between feeding mode and education of the mother. Mother's employment and sibling rank of the infant contributed to the model (p = 0.06 and p = 0.09, respectively). Infants' age when cereal was added was not related to the variables of gender or birth weight.

CONCLUSIONS

The finding that the mothers' decision whether or not to breastfeed was made prior to conception supports the importance of population-based education aimed at women in the child-bearing years as well as patient instruction early in the pregnancy. However, the duration of breastfeeding was shorter than was reported in the 1980s. Infants varied greatly in ages when the seven categories of complementary foods were added to their diets. Although recommendations for delaying introduction of solid foods until the infant is 4 to 6 months of age have been in place for more than a decade, about half the mothers in this study did so earlier. Characteristics of mothers who introduced cereal earliest (i.e., mean age of infants < 4 months) were more likely to be formula feeding when cereal was added, to feed cereal via the bottle, to be primiparous, to be employed outside the home, and/or not to cite the physician as a source for guiding the infant's transition to supplemental food.

Longitudinal study of nutrient and food intakes of infants aged 2 to 24 months

OBJECTIVE

To determine the nutrient and food intakes of healthy, white infants from families of middle and upper socioeconomic status and to compare intakes to current recommendations.

DESIGN

Using an incomplete random block design, we interviewed 98 mother-infant pairs longitudinally when infants were 2, 3, 4, 6, 8, 10, 12, 16, 20, and 24 months old. Data obtained included 24-hour dietary recalls, usual food intake, and food likes and dislikes.

SETTING

Interviews were conducted in the mother's home by registered dietitians. Subjects resided in two urban areas of Tennessee.

SUBJECTS

Of the original 98 subjects, 94 completed the 2-year study.

RESULTS

Mean energy and nutrient intakes generally met or exceeded the Recommended Dietary Allowance (RDA). Exceptions were zinc and vitamin D, which were each below 100% of the RDA at 9 of the 10 data points, and vitamin E, which was below the RDA in the infants' second year. Fat intake decreased from more than 40% of energy in the first 6 months to 30% to 32% from 10 to 24 months. One third of the infants drank reduced-fat milks at 12 months and more than half drank them at 24 months. Although infants ate a variety of foods, vegetables often were the least favorite foods. A variety of dairy products provided calcium for the infant but lacked vitamin D.

CONCLUSIONS

Several nutritional issues about infant feeding before 2 years of age arose. Low intakes of zinc, vitamin D, and vitamin E were observed. In the second year, low fat intake, use of reduced-fat milks, and dislike of vegetables were areas of concern.

Meningitis outbreaks and vaccination strategy

Three outbreaks of meningitis caused by Neisseria meningitidis serogroup A (subgroup III) are described: Niger (1991), Burundi (1992), and Guinea (1993). These outbreaks showed unusual characteristics: a shorter inter-epidemic interval (Niger), unusual geographical location outside the meningitis belt (Burundi and Guinea), and high age-specific attack rates in all age groups (Burundi and Guinea). Mass immunization campaigns mobilized considerable human and financial means (US $322,000 and 3000 person-days of work for health personnel to immunize 629,000 people in Guinea). The vaccination coverage was over 80% in densely populated areas (Burundi and urban Guinea), but below 50% in less populated areas (24/27 and 26/30 sub-districts in Niger and Guinea, respectively). The preventive fraction (proportion of cases prevented by vaccination) was substantial in Guinea (35% for a vaccine efficacy of 85%) and was higher where the campaign was initiated earlier. An 'alert' threshold indicating the onset of an epidemic of 15/100,000 cases in one week showed good sensitivity (94%), specificity (98%) and positive predictive value (89%) in Burundi, permitting quick decision making outside the meningitis belt. These 3 meningococcal meningitis outbreaks show the need for epidemic emergency preparedness and for vigilance on the whole African continent.

Prolonged MRI T2 times of the lentiform nucleus in idiopathic spasmodic torticollis

Using high-field MRI, we investigated possible morphologic changes in the basal ganglia of 22 patients with clinically diagnosed idiopathic spasmodic torticollis (iTs) compared with 28 age-matched normal controls. Two patients were found to have distinct basal ganglia lesions and were excluded from further analysis. The frequency of gross morphologic changes (atrophy, enlarged Virchow-Robin spaces) in patients was not significantly higher than in controls. However, T2 values calculated for the putamen and pallidum on both sides were significantly higher in the lentiform nucleus of the patients compared with the controls. In contrast, other well-defined subcortical regions did not exhibit a similar abnormality, nor did the optical or quantified signal analysis of various regions of interest show any differences. This finding suggests a morphologic abnormality in iTs that is not associated with a gross structural lesion. It could reflect focal gliosis and might correspond to earlier sporadic pathoanatomic descriptions of gliosis in idiopathic dystonia.

Embolization of a tentorial dural arterio-venous fistula presenting as atypical trigeminal neuralgia

A patient with a tentorial dural AV fistula causing atypical trigeminal neuralgia (TN) successfully treated by embolization is reported. The patient developed persisting throbbing facial pain in the distribution of the second and third division of the right trigeminal nerve (V2, V3) after a history of typical neuralgia for one year, preceded by a two month spell of TN 6 years previously and accompanied by right-sided pulsatile tinnitus for 10 years. The patient's mother, brother and sister were also said to be affected by typical trigeminal neuralgia. A right-sided dilated vein of Rosenthal due to a dural AV fistula fed by branches of the meningeal, occipital and meningo-hypophyseal trunk of the internal carotid artery was thought to cause trigeminal nerve compression. Complete resolution of symptoms after partial intra-arterial embolization of the main feeding arteries with N-butyroacrylate is described.

Magnetic resonance imaging in juvenile Canavan disease

We present a 2-year-old boy and a 6-year-old girl with mild Canavan disease (CD). Aspartoacylase activity in skin fibroblasts was deficient. Magnetic resonance imaging (MRI) of the brain did not show the prominent leucodystrophy previously reported in CD, but there was a hyperintense signal from the lentiform nuclei and the heads of the caudate nuclei on the T2-weighted MR images. This suggests a specific vulnerability of the corpus striatum in these patients. In the older patient, the white matter became affected at the age of 6 years. Proton magnetic resonance spectroscopy (1H-MRS) of white matter revealed a normal concentration of N-acetyl-L-aspartate (NAA) and a markedly decreased concentration of choline containing compounds (Cho) in the boy but a normal ratio of NAA to Cho in the girl. We conclude that deficient NAA catabolism affects myelin metabolism. This may present as changes in the striatum and/or as a low concentration of Cho before leucodystrophy appears on MRI.

Smoke production and smoke reduction in endoscopic surgery: preliminary report

This paper deals with the hazard of smoke production to patients undergoing endoscopic surgery. A study investigating methaemoglobin levels in a patient group operated on using smoke generating devices as compared to a control group yielded a significantly positive correlation between smoke production and methaemoglobin concentration. The mechanisms controlling methaemoglobin levels in the body and the specific toxic effect of elevated levels are dealt with. It is concluded that smoke production in endoscopic surgery is a factor of concern and should be minimized.

Human brain tumors: assessment with in vivo proton MR spectroscopy

To better understand variations in spectra of brain tumors, 122 in vivo proton spectra of brain tumors in 82 patients were analyzed. The changes in relative metabolite concentrations compared with those in normal spectra and the presence of any new metabolite were assessed. To evaluate the clinical usefulness of in vivo hydrogen-1 magnetic resonance (MR) spectroscopy in brain tumors, the authors looked for specific spectral changes on the basis of tumor grade. All tumor spectra showed differences from normal reference spectra. The differential diagnosis of the spectra was limited because intraindividual differences between spectra of one tumor at different locations were often larger than differences between spectra of tumors with different histologic characteristics. However, the variations in metabolite concentrations, and especially the presence or absence of aliphatic signals, were proved to be indicators of the histologic grade of tumor. The observed spectral patterns conformed to a four-compartment model, described herein, which is proposed to improve the interpretation of brain spectra.

The stability of human eye orientation during visual fixation

Using the magnetic search coil technique, gaze stability in the horizontal, vertical and torsional planes was measured binocularly in human subjects during visual fixation. Horizontal and vertical eye rotations exhibited a mixture of slow drifts and resetting microsaccades yielding an average standard deviation of 0.11 and 0.10 deg, respectively. In contrast, torsional rotations showed unsystematic smooth drifts with fewer saccades yielding an average standard deviation of 0.18 deg. The lower precision of gaze control in the torsional plane may reflect (i) a discrepancy between the encoding of retinal images in two dimensions but of ocular motor control signals in three dimensions, and (ii) the visual consequences of ocular drifts in the torsional plane, which differ from those in the horizontal and vertical planes.

Basis for receptor specificity of nonecotropic murine leukemia virus surface glycoprotein gp70SU

Murine leukemia viruses (MuLVs) initiate infection of NIH 3T3 cells by binding of the viral envelope (Env) protein to a cell surface receptor. Interference assays have shown that MuLVs can be divided into four groups, each using a distinct receptor: ecotropic, polytropic, amphotropic, and 10A1. In this study, we have attempted to map the determinants within viral Env proteins by constructing chimeric env genes. Chimeras were made in all six pairwise combinations between Moloney MCF (a polytropic MuLV), amphotropic MuLV, and 10A1, using a conserved EcoRI site in the middle of the Env coding region. The receptor specificity of each chimera was determined by using an interference assay. We found that amphotropic receptor specificity of each chimera was determined by using an interference assay. We found that amphotropic receptor specificity seems to map to the N-terminal portion of surface glycoprotein gp70SU. The difference between amphotropic and 10A1 receptor specificity can be attributed to one or more of only six amino acid differences in this region. Nearly all other cases showed evidence of interaction between Env domains in the generation of receptor specificity. Thus, a chimera composed exclusively of MCF and amphotropic sequences was found to exhibit 10A1 receptor specificity. None of the chimeras were able to infect cells by using the MCF receptor; however, two chimeras containing the C-terminal portion of MCF gp70SU could bind to this receptor, while they were able to infect cells via the amphotropic receptor. This result raises the possibility that receptor binding maps to the C-terminal portion of MCF gp70SU but requires MCF N-terminal sequences for a functional interaction with the MCF receptor.

Vestibular-neck interaction of human ocular counterroll

Compensatory rolling of the eye about the line of sight (ocular counterroll, OCR) was studied in four normal human subjects during 10 min of lateral tilt (20 degrees to the left/right) of body, head and trunk. OCR was objectively measured at 1-min intervals by determining the rotation of a circular sample of iris pattern using a videocamera and digital image processing. Body and head tilt caused symmetrical OCR (range 2.4 to 9.5 degrees) to either side, whereas trunk tilt induced no significant change in torsional eye position. No adaptation in OCR was found during the time spent in tilted orientation in neither paradigm though unsystematic torsional fluctuation was a regular finding in all subjects. These findings are taken as evidence that only the non-adapting otolith system, as opposed to the proprioceptive system of the neck, contributes to the generation and maintenance of OCR.

[Nuclear magnetic resonance tomography and differential diagnosis of Hallervorden-Spatz disease]

The case of a 15 year old male patient with progressive dystonia, dysarthria and dementia is presented. No diagnosis could be found on clinical grounds. Low field MRI (0.23 T) demonstrated bilateral necrosis in the globus pallidus of clinically unknown etiology. Only high field imaging (2.0 T) revealed a pattern of lesions which is supposed to be specific for Hallervorden-Spatz disease (HSD): bilateral symmetrical decreased signal intensity in the globus pallidus secondary to the T2* effect of paramagnetic substances, principally iron. The neuroradiological differential diagnosis and pathognomonic signs of HSD are discussed.

CT and MRI: prognostic tools in patients with AIDS and neurological deficits

To determine the prognostic value of CT and MRI in AIDS we studied the survival of patients with neurological involvement, in relation to the initial imaging results. Twenty-six initial CT and 15 MRI examinations of 41 patients were reviewed for the presence of cerebral atrophy and/or focal lesions. The mean survival time of patients with initially normal imaging was longer (700 +/- 89 days) than that of patients with isolated cerebral atrophy (326 +/- 65) or isolated focal lesions (202 +/- 97). The shortest survival (78 +/- 44 days) was found in patients with both cerebral atrophy and focal lesions. The risk of death in patients with atrophy alone was 3.6 times higher, that in patients with focal lesions alone 6.4 times higher, and in patients with both changes 19.3 times higher than in patients with initially normal imaging. Cerebral imaging with CT and/or MRI thus allows identification of AIDS-related cerebral changes and may contribute to assessment of prognosis.

Global tracking of the ocular fundus pattern imaged by scanning laser ophthalmoscopy

This paper presents an algorithm for the automatic global tracking of ocular fundus landmarks in video image sequences generated by scanning laser ophthalmoscopy (SLO). The tracking algorithm is based on the computation of the discrete unnormalized cross-correlation of an interactively preselected small template and respective images in time sequences of fundus patterns. The correlation is executed with binary images derived from an automatical threshold limitation of the grey-value images. Due to the [+1/-1] representation of the binary images the unnormalized correlation functions directly relate to the Hamming distance of the template and the objects in the images. Experiments show that even templates with features distorted by noise are accurately recognized at any position. The accuracy of position detection is better than 0.4%. Possible hardware implementations of the algorithm which would reduce computation time are briefly mentioned.

Video-oculographic measurement of 3-dimensional eye rotations

An effective and relatively calibration-free method for the measurement of 3-dimensional eye rotations is described. The experimental method consists of recording with a video camera the positions of distinct globe markers provided by a tight-fitting, soft contact lens before and after an eye rotation. The mathematical analysis represents the eye rotation by a rotation vector (rotation axis and angle) and three, spherical Euler angles. The method is linear over the entire range of natural eye rotation, the resolution limited only by the video set-up used. Due to its easy applicability, the system is well suited for various eye movement measurements in clinical or research environments.

Control of arm movements in a 2-dimensional pointing task

The present study analyses in humans the control principles of sequential, unpracticed pointing movements in a 2-dimensional space. Our data reveal that variable pointing errors add up within such sequences. This finding supports the hypothesis that movement amplitude rather than position is the controlled variable of the investigated movements.

Large colloid cyst in lateral ventricle simulating brain tumour. Case report

This case report describes a patient presenting with symptoms of increased intracranial pressure, whose computerized tomographic (CT) scan was highly suggestive of a large low-grade glioma invading the basal ganglia. Magnetic resonance imaging (MRI) revealed a well-demarcated space-occupying mass of increased intensity in the left lateral ventricle and adjacent white matter. Following stereotactic biopsy, which yielded a homogeneous jelly-like material, the mass was removed microsurgically and was found to be most like a colloid cyst on histological examination. Discussion focuses on the clinical and differential diagnostic implications of this very unusual combination of findings.