Osmolality of fortified donor human milk: An experimental study

BACKGROUND

We quantify the osmolality of human milk fortified with human milk fortifiers (HMFs), powder infant formulas and protein additives.

METHODS

Commercial liquid HMFs and powder infant formulas were added to pasteurized pooled donor human milk in triplicate and stirred. The osmolality of unfortified and fortified human milk at 22, 24, 26, 27, 28, and 30 kcal/oz (0.73, 0.8, 0.87, 0.9, 0.93, and 1 kcal/ml, respectively) was determined using freezing-point depression.

RESULTS

The osmolality of fortified human milk associated with energy density in a linear relationship regardless of the fortification strategies. Multiple liquid HMFs and every powder infant formula exceeded the osmolality threshold of 450 mOsm/kg H2 O within the energy densities tested.

CONCLUSION

The osmolality of fortified human milk is highly variable and should be considered when selecting a fortifying agent for human milk.

Displacement of human milk during fortification: An experimental study

BACKGROUND

This study quantified the displacement of human milk by commercial human milk fortifiers (HMFs) and infant formulas.

METHODS

Commercial liquid HMFs and powder infant formulas were added to pasteurized pooled donor human milk in triplicate, stirred, and weighed. The difference in weight between unfortified and fortified human milk at 22, 24, 26, 27, 28, and 30 kcal/ounce was calculated.

RESULTS

The displacement of human milk by liquid HMFs and powder infant formulas and powder HMF was highly associated with energy density. A human milk-derived HMF displaced significantly more human milk when compared with bovine milk-derived HMFs at equivalent energy densities. Similarly, powder infant formulas displaced less human milk when compared with a powder HMF, and the addition of hydrolyzed powder infant formulas resulted in less human milk displacement when compared with nonhydrolyzed powder infant formulas.

CONCLUSIONS

The displacement of human milk by commercial liquid HMFs and infant formulas must be considered when selecting a fortifying strategy.

Acid/base balance in fortified donor human milk: An experimental study

BACKGROUND

Our goal was to quantify the pH and total acidity of human milk fortified with human milk fortifiers (HMFs), powder infant formulas, and protein additives.

METHODS

Commercial liquid HMFs and powder infant formulas were added to pasteurized pooled donor human milk in triplicate and stirred. The pH of unfortified and fortified human milk at 22, 24, 26, 27, 28, and 30 kcal/ounce (624, 680, 737, 765, 794, and 850 kcal/g, respectively) was determined using a pH meter. Phenolphthalein acidity at 24 and 30 kcal/ounce (680 and 850 kcal/g, respectively) was determined using diluted sodium hydroxide.

RESULTS

The pH of unfortified human milk increased within the first hour (6.52 ± 0.06 vs 6.62 ± 0.05, P < 0.0001). Changes in pH largely correlated with caloric density; however, directional changes varied considerably between HMFs and powder infant formulas. Two liquid HMFs demonstrated modest reductions in pH with increasing caloric density whereas one liquid HMF alkalinized human milk with increasing caloric density (analysis of variance P < 0.0001). Phenolphthalein acidity was significantly higher for five HMFs and lower for one HMF at 30 kcal/ounce (850 kcal/g) but not 24 kcal/ounce (680 kcal/g). Powder infant formulas generally increased pH with increasing caloric density (analysis of variance P < 0.0001), but no differences in phenolphthalein acidity were noted.

CONCLUSION

Changes in acid/base balancefor fortified human milk are variable and may be a consideration when selecting a fortifying agent for human milk.

A mobile application for STEMI care optimization: pilot implementation project report

Background

In an effort to improve outcomes of STEMI patients, we developed a secure mobile application (app) to streamline real-time communication and coordination between multiple teams taking care of STEMI patients in a large health care system. The app includes multi-level alarm and notification systems, instant EKG transmission for quick interpretation, activation of the cardiac catheterization laboratory (CCL) after expert case review, secure video chat among team members facilitating clinical discussion, continuous updates on patients' clinical status and ambulance location tracking.

Purpose

One of the major shortcomings in STEMI system of care has been long delays in transfer of patients from non-PCI capable hospitals to a receiving center for primary PCI. To address the challenges of interhospital transfer, we designed a pilot project employing the app for STEMI transfer from a first contact hospital to our CCL. This report assesses the effect of the app on door-to-device time by comparing the key metric for STEMI transfer before (historic) and after app launch.

Methods

The pilot project involved key leadership stakeholders from Emergency Medicine and Nursing Departments at the referring hospital, CCL and our transfer center. During pilot period (July 2021 to January 2022) the referring center activated STEMI alarms using app activation in parallel with the previously established STEMI activation process via traditional phone calls to the transfer center. The built-in workflow redundancy was introduced to ensure the rapid and efficient, and at the same time, safe and reliable response to STEMI alert. In preparation for the pilot, more than 250 people were provisioned accounts, trained on their user-specific roles and scheduled in the app according to their schedules.

Results

A total of 40 suspected STEMIs were activated through the app during the pilot study; among them 30 cases were accepted for transfer and 10 rejected. After excluding patients who expired during transfer, were intubated, or had normal coronaries, final study population included 13 STEMI cases activated through the app. These cases were compared with 43 STEMIs activated through the traditional pathway from January 2019 to July 2021 before app launch. After implementing the app, the mean door-to-device time for STEMI transfer decreased from 120.3±48.3 to 91.8±15.4 min (P=0.002) (Figure 1). The significant improvement, 29 min (24%), of the key metric for interhospital transfer resulted in all STEMI cases meeting AHA goal of door-to-device time ≤120 minutes after the app launch. The respective percent of STEMI cases meeting the goal before app was 71% (Figure 2).

Conclusions

Implementation of a mobile app into STEMI workflow of a large urban healthcare system had a significant impact on the quality of care for transfer of STEMI patients, which has also helped bring our clinical practice closer to the AHA guidelines pertaining to the first door-to-device time.

Funding Acknowledgement

Type of funding sources: None.

Characterization of neuropsychiatric symptoms in a group of individuals with manifest or pre-motor Huntington’s disease in Medellín, Colombia

Introduction

Huntington’s disease (HD) is a rare (1-9/100 000), inherited disease characterized by an elongated CAG repeat on chromosome 4p, leading to a degeneration of neurons. Also, psychiatric symptoms are very common in the early stage and may appear before motor symptoms.

Objectives

To characterize neuropsychiatric symptoms in a group of individuals with manifest or pre-motor Huntington’s disease in Medellín, Colombia.

Methods

Data obtained from clinical records of individuals with HD (motor-manifest or pre-motor with triplets count) evaluated for ENROLL-HD project in the Group of Neuroscience of Antioquia. We explored variables related to substances abuse, neuropsychiatric symptoms, the respective age of onset, sex, and triplet count when available.

Results

Twenty-six (53%) were women, 8% had a familiar history of psychotic illness in a first-degree relative and 88% presented motor symptoms. Also, 59% had a history of depression, 53% irritability, 57% aggressiveness, 34% apathy, 29% perseverative/obsessive behavior, 14% psychosis, and 30% mild cognitive impairment. Ten individuals (20%) had motor without neuropsychiatric symptoms. Also, thirty-seven individuals (76%) presented motor and neuropsychiatric symptoms; of these, 41% had neuropsychiatric symptoms before motor symptoms. No psychiatric symptoms were associated with the use of alcohol, cigarettes, or drugs of abuse.

Conclusions

Neuropsychiatric symptoms are highly prevalent among individuals with HD and studies oriented to create relevant knowledge for the development of advice oriented to people with this disease are necessary.

Disclosure

No significant relationships.

Neuropsychiatric Symptoms in Parkinson’s Disease with and without Mild Cognitive Impairment

Objective

Neuropsychiatric symptoms (NPS) are common clinical features of patients with Parkinson’s disease (PD). However, such symptoms in non-demented PD patients have scarcely been investigated. To address this issue, we describe the neuropsychiatric profile in PD patients with and without Mild Cognitive Impairment (MCI).

Participants and Method

Eighty non-demented PD patients were included. The patients were divided into two groups depending on the presence or absence of MCI (PD-MCI and PD-nMCI, respectively). MCI diagnosis was made according to the Movement Disorder Society Task Force Level I criteria. NPS were evaluated using the Neuropsychiatric Inventory (NPI). For each domain, the presence and magnitude of symptoms (frequency x severity) was calculated. The total NPI score was also computed, in which higher scores suggest greater behavioral disturbance.

Results

PD-nMCI (n = 59, 74%) and PD-MCI (n = 21, 26%) groups were similar in the disease stage and years since diagnosis. In contrast with the PD-nMCI group, participants in the PD-MCI group were older. Fourteen PD-MCI (66%) and 45 PD-nMCI (76%) patients reported at least one neuropsychiatric symptom in the previous month. In both groups, the most frequent NPS were sleep disorders, depression, anxiety, apathy, irritability, and disinhibition. Additionally, the proportion of these symptoms between groups did not differ significantly (p &gt; 0.05). There was only a tendency of greater score in the disinhibition subscale in PD-MCI group (p &lt; 0.02). In both groups, NPS were not associated with clinical variables (years since diagnosis, Unified Parkinson's Disease Rating Scale -III) after adjusting for age.

Conclusions

Preliminary findings suggest that NPS are frequent in PD patients independent of the degree of cognitive impairment, and they may encompass non-motor features of the clinical spectrum of the disease. Further longitudinal investigations are needed to determine whether such symptoms may predict the cognitive decline in these patients.

A Novel Method for the Treatment of Bilateral Hypogastric Aneurysms Using Hybrid Polytetrafluoroethylene Graft

Open aortic aneurysm repair in the setting of bilateral hypogastric aneurysms is technically challenging. We present a novel technique for open surgical repair for bilateral hypogastric aneurysms using the Gore hybrid vascular graft (GVHG; W. L. Gore and Associates Inc, Flagstaff, Arizona). The GVHG is an expanded polytetrafluoroethylene graft with a nitinol stent at 1 end designed for hemodialysis access. The GVHG has been also been used for aortic debranching and treatment of occlusive disease. We describe the first report using GVHG to repair hypogastric aneurysms.

Deciphering interference control in adults with ADHD by using distribution analyses and electromyographic activity

A deficit in "interference control" is commonly found in adults with Attention Deficit Hyperactivity Disorder (ADHD). This has mainly been interpreted as difficulties in inhibiting inappropriate responses. However, interference control involves processes other than simply the ability to inhibit. Consequently, we used sophisticated analysis to decipher the additional processes of interference control in these patients. We compared interference control between 16 adults with ADHD and 15 control adults performing a Simon task. In most studies, performance is generally reported in terms of mean error rates and reaction times (RTs). However, here we used distribution analyses of behavioral data, complemented by analyses of electromyographic (EMG) activity. This allowed us to better quantify the control of interference, specifically the part that remains hidden when pure correct trials are not distinguished from partial errors. Partial errors correspond to sub-threshold EMG bursts induced by incorrect responses that immediately precede a correct response. Moreover, besides "online" control, we also investigated cognitive control effects manifesting across consecutive trials. The main findings were that adults with ADHD were slower and showed a larger interference effect in comparison to controls. However, the data revealed that the larger interference effect was due neither to higher impulse expression, nor to a deficit in inhibition but that these patients presented a larger interference effect than the controls after congruent trials. We propose and discuss the hypothesis that the interference control deficit found in adults with ADHD is secondary to impairments in sustained attention.

A cooperative interaction between LPHN3 and 11q doubles the risk for ADHD

In previous studies of a genetic isolate, we identified significant linkage of attention deficit hyperactivity disorder (ADHD) to 4q, 5q, 8q, 11q and 17p. The existence of unique large size families linked to multiple regions, and the fact that these families came from an isolated population, we hypothesized that two-locus interaction contributions to ADHD were plausible. Several analytical models converged to show significant interaction between 4q and 11q (P<1 × 10(-8)) and 11q and 17p (P<1 × 10(-6)). As we have identified that common variants of the LPHN3 gene were responsible for the 4q linkage signal, we focused on 4q-11q interaction to determine that single-nucleotide polymorphisms (SNPs) harbored in the LPHN3 gene interact with SNPs spanning the 11q region that contains DRD2 and NCAM1 genes, to double the risk of developing ADHD. This interaction not only explains genetic effects much better than taking each of these loci effects by separated but also differences in brain metabolism as depicted by proton magnetic resonance spectroscopy data and pharmacogenetic response to stimulant medication. These findings not only add information about how high order genetic interactions might be implicated in conferring susceptibility to develop ADHD but also show that future studies of the effects of genetic interactions on ADHD clinical information will help to shape predictive models of individual outcome.

Pedigree disequilibrium test (PDT) replicates association and linkage between DRD4 and ADHD in multigenerational and extended pedigrees from a genetic isolate

Association/linkage between dopamine D4 receptor (DRD4) polymorphisms and attention-deficit/hyperactivity disorder (ADHD) has been suggested by case-control- and nuclear-family-based studies. Here, we present a candidate gene analysis for DRD4 using 14 extended and multigenerational families segregating ADHD derived from the 'Paisa' community of Antioquia, Colombia, a genetic isolate. Two DRD4 polymorphisms (a 120 bp tandem duplication at the promoter and a 48 bp-VNTR at exon 3), reported associated to ADHD, were genotyped. Parametric and non-parametric linkage analyses, and a family-based association test (FBAT), the pedigree disequilibrium test (PDT), were applied to search for evidence of association/linkage. Two-point LOD scores were significantly negative, with values ranging from -3.21 (P=0.011158) to -7.66 (P=0.000091 at theta=0). Non-parametrical analysis resulted in nonsignificant evidence for linkage. The PDT showed a moderate trend toward significance of association/linkage between the 7-repeat (7R) allele at the 48 bp VNTR and ADHD (P=0.0578). Furthermore, the haplotype analysis shows a significant association/linkage of the 7R-240 bp haplotype (P=0.0467) with ADHD. Results suggest that either a moderate DRD4 genetic effect, or linkage disequilibrium of DRD4 with an ADHD disease locus in the vicinity or the linkage to a phenotypic component of the ADHD spectrum could be underlying this association/linkage. These results provide further evidence for the association of ADHD to genetic variation in or near to DRD4 and replicate the previously reported association between ADHD and the 7R allele.

Attention-deficit/hyperactivity disorder (ADHD): feasibility of linkage analysis in a genetic isolate using extended and multigenerational pedigrees

Segregation analyses converge in explaining the predisposition to attention-deficit/hyperactivity disorder (ADHD) as the consequence of a major gene and exclude purely environmental or cultural transmission. As a result of the ADHD phenotype restrictions, collection of extended families or design of linkage studies using families has been extremely difficult and thus currently linkage studies have been performed using only concordant or discordant sib-pairs rather than large families. On the other hand, intergenerational studies are represented by the transmission disequilibrium test (TDT) using trios. We collected pedigree data on ADHD from the Paisa community from Antioquia, Colombia, a genetic isolate. The goal of this study was to genetically map a putative gene predisposing to ADHD in a set of 27 multigenerational Paisa families. Here we present the results of a power simulation using SIMLINK to detect linkage of ADHD. ADHD was assumed to be a dichotomous trait with incomplete penetrance and a phenocopy rate of 3% in males and 0.2% in females. We simulated cosegregation of the trait and a marker locus in our pedigrees. We assumed Hardy-Weinberg and linkage equilibrium, equally frequent marker alleles and evaluated power at several recombination fractions between the trait and marker loci. Also, the ADHD trait was assumed to be genetically heterogeneous and different functions of age-dependent penetrance were simulated. We found exceptionally good power to detect linkage (expected LOD > 14 if theta is 0.1 or less), and that the presence of heterogeneity up to 50% does not affect substantially the projected LOD scores even for a theta recombination value of 0.05 (eLOD > 5.87). Having now obtained blood samples and confirmatory interviews in five families (representing 20% of the projected number of families), we performed a new analysis. The expected mean LOD in these five families reached values close to 10 and remained invariant when heterogeneity and different penetrance models were considered. We discuss the relative benefits of using extended and multigenerational families for genetic mapping studies as opposed to using nuclear families, affected sib pairs or sporadic cases which require the collection of over 1000 analytical units to get the same power exhibited by the small number of pedigrees described here.

A novel Cys212Tyr founder mutation in parkin and allelic heterogeneity of juvenile Parkinsonism in a population from North West Colombia

We report the molecular characterization of three multiplex families and a sporadic case of juvenile Parkinsonism identified in the province of Antioquia (Colombia). Linkage and haplotype analysis using markers in 6q25.2-27 indicated that Parkinsonism in the pedigrees is linked to the parkin gene (maximum LOD-score of 3.85) but that they carry two different mutant haplotypes. Sequence analysis revealed a novel G to A transition in exon 6 at position 736 (G736A) of parkin. This change results in a non-conservative cysteine for tyrosine substitution. All affected individuals from two families were homozygous for this mutation, which was not detected in 100 normal controls. Patients from the family carrying the second haplotype and the sporadic case were homozygous for a GT insertion in exon 3. This mutation has been previously identified in French families with juvenile Parkinsonism. The concomitant presence of founder effects and allelic heterogeneity in Antioquia might relate to the founding admixture at the origin of this population.

Searching for the prototypic eye genetic network: Sine oculis is essential for eye regeneration in planarians

We have identified a sine oculis gene in the planarian Girardia tigrina (Platyhelminthes; Turbellaria; Tricladida). The planarian sine oculis gene (Gtso) encodes a protein with a sine oculis (Six) domain and a homeodomain that shares significant sequence similarity with so proteins assigned to the Six-2 gene family. Gtso is expressed as a single transcript in both regenerating and fully developed eyes. Whole-mount in situ hybridization studies show exclusive expression in photoreceptor cells. Loss of function of Gtso by RNA interference during planarian regeneration inhibits eye regeneration completely. Gtso is also essential for maintenance of the differentiated state of photoreceptor cells. These results, combined with the previously demonstrated expression of Pax-6 in planarian eyes, suggest that the same basic gene regulatory circuit required for eye development in Drosophila and mouse is used in the prototypic eye spots of platyhelminthes and, therefore, is truly conserved during evolution.

Correlation between intelligence test scores and executive function measures

In this study, some executive function measures (Wisconsin Card Sorting Test [WCST], verbal fluency, and Trial Making Test [TMT], Form A and Form B) were correlated with Wechsler Intelligence Scale for Children-Revised (WISC-R) scores. Fifty 13- to 16-year-old normal children were selected. It was found that verbal fluency tests correlated about 0.30 with Verbal Intelligence Quotient (IQ) and Full Scale IQ. In the WCST only Perseverative Errors negatively correlated with Verbal IQ and Full Scale IQ. Two correlations were found to be significant with regard to the TMT: TMT Form B Errors negatively correlated with WISC-R Vocabulary subtest; and TMT Form A Time negatively correlated with Performance IQ. These results support the assumption that traditional intelligence tests are not appropriately evaluating executive functions.

Prevalence of attention-deficit/hyperactivity disorder symptoms in 4- to 17-year-old children in the general population

The purposes of this study were (a) to estimate the prevalence of Attention-Deficit/Hyperactivity Disorder (AD/HD) symptoms in the general preschool and school population; and (b) to analyze the influence of gender, age, and socioeconomic status (SES) variables on AD/HD symptoms. Out of the 80,000 preschool and schoolchildren living in Manizales, Colombia, a random sample of 540 children was selected. Two gender, three age (4- to 5-year olds, 6- to 11-year olds, and 12- to 17-year olds), and three SES (low, middle, and high) groups were used. The 18 DSM-IV symptoms corresponding to AD/HD Criterion A were assessed on a scale of 0 (never) to 3 (almost always). All three demographic variables established statistically significant differences: AD/HD symptoms were more frequent in 6- to 11-year-old, low-SES, male participants. DSM-IV Criterion A for AD/HD was fulfilled by 19.8% of the boys and 12.3% of the girls. However, this difference was marginally significant only in the AD/HD Subtype I: Combined. It was concluded that demographic variables are significant correlates of the AD/HD diagnosis. The prevalence found in this study was higher than usually reported, even though only the symptomatic DSM-IV AD/HD criterion was analyzed. We failed to confirm the assumed AD/HD gender ratio.

[Discrimination between genetic factors in attention deficit]

INTRODUCTION AND OBJECTIVE

In order to elucidate the genetic and environmental components involved in the susceptibility to develop attention deficit hyperactivity disorder (ADHD), a complex segregation analysis on nuclear families (n = 53) ascertained from affected probands belonging to Medellín, in the Antioquian State, Colombia, was performed.

METHODS AND RESULTS

Models of cohort effect (non-inheritance), multifactorial, recessive major gene, non-major gene component and non-transmission of major gene were rejected. Contrarily, dominant and codominant major gene models and non-multifactorial component could not be rejected. Thus, the better model fitting the data was that of the major gene (dominant/codominant). This major gene explains more than 99.99% of the ADHD phenotypic variance (value of heritability in the mixed model equal to 0.007%), which permit to assume a low aport of the environmental component to the phenotype ADHD. Gene frequency of the major gene was 3% in the general population of Antioquia and its penetrance was closed to 30%.

CONCLUSION

Some cautions and aspects related to the bias of the interview and diagnosis of the parents are discussed.

Neuropsychological and behavioral assessment of ADHD in seven- to twelve-year-old children: a discriminant analysis

We hypothesized that children with attention-deficit/hyperactivity disorder (ADHD) would underperform on neuropsychological tests that are sensitive to executive function impairments. We further proposed that a linear discriminant analysis using behavioral and neuropsychological variables as dependent variables would pinpoint the capability of behavioral questionnaires and neuropsychological tests to predict the correct classification of ADHD and control children. We designed a transversal study with 62 seven- to twelve-year-old children with ADHD and 62 Full Scale IQ-matched controls using two behavioral scales and 13 neuropsychological tests. Using analysis of variance and covariance with age and school achievement and multifactor analysis of variance, we found that behavioral variables established robust, statistically significant differences between groups (p < .001). Children with ADHD scored worse than controls on 31 out of 61 neuropsychological variables. Children with ADHD, however, obtained better scores that were statistically significant on WISC-R Comprehension and Picture completion. A linear discriminant analysis with nine behavioral variables correctly classified 100% of the participants in both groups. Another linear discriminant analysis using 10 neuropsychological variables correctly classified 85.48% of the participants in both groups. We propose a core battery of selected tests for assessing children with ADHD. The significance of cross-cultural analyses of different developmental disturbances is emphasized.

High altitude living: genetic and environmental adaptation

High altitude (HA) living produces physiological changes for adaptation to chronic hypobaric-hypoxemic conditions. Although much is known about these physiologic adaptations, no clear separation has been made regarding what is "native" or "genetic" adaptation and what is "acquired." In this review, we describe the genetic vs. acquired adaptation and only include studies performed in a population native to HA and not in an acclimatized population or trekkers. The changes encountered in animals and humans living at HA in terms of hematology, muscular, respiratory, cerebral, cardiovascular, hormonal, fluid and electrolytes and reproduction, strongly suggest that genetics play a very important role in HA adaptation. Unfortunately, the characteristic physiology of HA natives has not been systematically defined to established specific measurable parameters of adaptation in comparison to the acquired ambient adaptation of the non-native population. Once the parameters are established, we can compare non-native populations exposed to HA that must emulate the HA physiology for a definite adaptation to be present. With measurable parameters, especially in the management of fluids and electrolytes, we can define how long it will take for a sea level native to adapt to an HA altitude. Until these studies are performed, speculation will continue and no rational medical intervention can be offered to HA newcomers who may experience HA difficulties.

Executive dysfunctions in children with attention deficit hyperactivity disorder

One hundred and twenty-four male children ranging in age from seven to 12 years-old were selected. The sample was divided into two groups: (1) sixty-two with attention deficit hyperactivity disorder (ADHD) children; and (2) sixty-two normal matched controls (N-ADHD). Three tests were individually administered: (1) Wisconsin Card Sorting Test (WCST); (2) Verbal fluency and semantics (animals and fruits); and, (3) Picture Arrangement subtest of the WISC-R. For all the test scores, statistically significant differences were found between both ADHD and N-ADHD groups. Two separate factor analyses were performed, using the normal and ADHD groups. Four factors were found for the N-ADHD group, which accounted for 85.7% of the variance. The factor structure presented some similarities in both groups: Factor 2, 3 and 4 in the control group corresponded to factors 1, 2 and 3 in the ADHD group. Nonetheless, in the ADHD group Factor 1 (Abstraction and Flexibility Factor) was absent. Results are interpreted as supporting the hypothesis of executive dysfunction in children with ADHD.

Individual differences in memory and executive function abilities during normal aging

The purpose of this study was to analyze the effects of some individual variables on memory and executive function test performance in normal aging individuals. Sixty subjects (21 males and 39 females), with a mean age of 69.66 (SD = 7.09) were selected. The following neuropsychological tests were selected. The following neuropsychological tests were administered: Associative Learning and Logical Memory from the Wechsler Memory Scale (WMS) (Wechsler, 1945), Associative Memory with Semantic Enhancement Test (AMSET) (Pineda, Galeano and Giraldo, 1991), Wisconsin Card Sorting Test (WSCT) (Heaton, 1981), and Verbal Fluency (phonologic and semantic). The effects of demographic (age, education, and sex) and some individual variables (academic history, working history, physical activity, and leisure activities) were measured. Age and education effects on test scores were observed, but no sex effect was found. Working history and leisure activities established significant differences in some test scores. A multiple regression analysis was performed. Not only demographic variables, but also individual variables were associated with memory, and albeit at a lesser extend, with executive function test scores. It was emphasized that not only demographic factors, but also individual variables have a significant effect on cognitive changes observed during normal aging.

Assessment of lidar inversion errors for homogeneous atmospheres

The inversion of lidar returns from homogeneous atmospheres has been done customarily through the well-known slope method. The logarithmic operation over the range-corrected and system-normalized received signal used in this method introduces a bias in the statistics of the noise-affected processed signal that can severely distort the estimates of the atmospheric attenuation and backscatter coefficients under measurement. It is shown that a fitting of the theoretically expected exponential signal to the range-corrected received one, using as the initial guess the results provided by the slope method and a least-squares iterative procedure, can yield enhanced accuracy under low signal-to-noise ratios and especially in moderate-to-high extinction conditions.

Partial renal resistance to arginine vasopressin as an adaptation to high altitude living

BACKGROUND

The normal physiological response to high altitude (HA) is a decrease in total body water (TBW) and plasma and extracellular volume. The present investigation was designed to determine the mechanisms of the decrease in TBW with HA adaptation.

METHOD

There were 10 men from the Southern Colombian Andes (2600 m) in Pasto, Colombia, who were compared to age-matched men from sea level (SL), Tampa, FL, in the U.S., with respect to their TBW, ability to handle a water load and response to exogenous arginine vasopressin (AVP). Measurements included circulating AVP, atrial natriuretic peptides [atrial natriuretic factor (ANF) and vessel dilator], and urinary excretion of the AVP sensitive water channel, aquaporin-2 (AQP2).

RESULTS

The HA subjects had significantly (p < 0.01) lower TBW (29.37 +/- 0.98 vs 39.71 +/- 1.66 Kg), AQP2 excretion and vessel dilator circulating levels at baseline compared to SL subjects. ANF levels were not significantly different between the two groups. With water loading (20 ml.kg-1 in 15 min) there was a rapid increase in urine volume at 30 min with a decline thereafter in HA subjects while SL subjects had a gradual increment peaking at 120 min. There was a significant (p < 0.05) decrease in plasma AVP in the SL subjects within 30 min after the water load while the HA subjects had no significant decrease in AVP levels. Excretion of AQP2 decreased significantly after the water load only in the SL subjects. Administration of exogenous AVP increased AQP2 3- to 4-fold in the HA in comparison to SL subjects.

CONCLUSIONS

Present data demonstrate the following adaptations to HA: decrease in TBW, better ability to handle a water load despite high levels of AVP, a significant decrease in the circulation of vessel dilator, and diminished excretion of AQP2 water channel. These findings indicate an insensitivity of the collecting duct of HA subjects to the actions AVP. However, exogenous administration of AVP caused a marked excretion of AQP2.

[Prevalence of neurocysticercosis in individuals affected by epilepsy]

INTRODUCTION

In this investigations, was carried out a neurocysticercosis (NC) prevalence study during seven months in the Instituto Neurológico de Antioquia with the purpose of known neurocysticercosis frequency as cause of epilepsy in patients older than ten years that we attended in our institute.

MATERIAL AND METHODS

Computerized tomographies (CT) were made to 503 patients, with epilepsy, 24.7% of them were CT positive for NC. Cysticercosis enzyme linked immunoelectrotransfer blot (EITB) and enzyme linked immunoabsorbent assay (ELISA) test were made to 178 patients, 19.6% were EITB positive for NC and 5% ELISA positive for NC. Results. From this result it is possible to infer that about 8% of the 503 patients with epilepsy had cysticercosis, according to EITB that is the golden assay for NC. The CT and ELISA test had 94.3% and 27.7% sensitivity, respectively, according to EITB. The specificity of the CT for NC was 49.2% and specificity for ELISA test was 100% as compared to EITB. The multivariate analysis with logistic regression allowed to establish association of positive EITB with factors such as male sex, eating pork, headaches and multiple lesions in CT.

CONCLUSIONS

Prevention and education actions are necessary for the interruption of the neurocysticercosis transmission chain in order to diminish the high prevalence of epilepsy in the country and its complication and consequences.

The effects of high altitude on hypothalamic-pituitary secretory dynamics in men

OBJECTIVE

Individuals adapted to high altitude (HA) have abnormalities in endocrine function and specifically in the pituitary-thyroid axis and aldosterone regulation. In this study we assessed hypothalamic-pituitary function in men adapted to high altitude living using exogenous administration of synthetic hypothalamic hormones.

DESIGN

Growth hormone releasing hormone (Geref 1-29) 1 microgram/kg, TRH 500 micrograms, GHRH 100 micrograms and ovine corticotrophin releasing hormone (oCRH) 1 microgram/kg were simultaneously administered intravenously to two groups of men: 12 born and raised in the city of Pasto, Colombia, South America, located at an altitude of 2600 m in the southern Colombian Andes (HA group) and 10 men living at sea level (SL) in Tampa, Florida.

MEASUREMENTS

The following hormones were measured: GH, IGF-I, TSH, T4, free T4, free T3, PRL, ACTH, beta-endorphin and cortisol. IGF binding protein-3 (IGFBP-3) and cortisol binding globulin (CBG) were also measured.

RESULTS

GH response to GHRH in HA men was exaggerated compared to SL men, and IGF-I concentration was also significantly increased in the presence of normal levels of IGFBP-3. No differences in TSH or PRL responses were found following TRH. HA men had lower basal total T4 levels, but higher free T4 and free T3 concentrations. The basal ACTH concentrations in the HA men were significantly lower than SL, although the response to oCRH was still present. beta-Endorphin basal levels were similar at HA and SL but the response to oCRH at HA was blunted. At HA, basal cortisol levels as well as CBG were elevated compared to SL and, in contrast to SL, did not increase significantly after endogenous ACTH secretion.

CONCLUSIONS

This study is the first description of exaggerated GH response to the administration of GHRH in HA men and also of a significant increase in IGF-I concentration in the same subjects in the presence of normal levels of IGFBP-3. An altered hypothalamic-pituitary response was found in HA men after administration of oCRH characterized by a significantly lower basal ACTH concentration at HA, although the response to oCRH was present but the beta-endorphin response to oCRH was blunted. At HA, basal cortisol levels, as well as CBG, were elevated and the cortisol levels did not significantly increase after endogenous ACTH secretion. We have characterized the differences in hypothalamic-pituitary dynamics after the administration of TRH, GnRH and oCRH in HA men comparing their response to age/sex matched SL men.