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Biomedical subjects

A Martin

Publications and source records attributed to A Martin.

At least 199 records · Page 11Linked to original sources

Successful treatment of invasive nasal cryptococcosis in a ferret.

Invasive cryptococcal rhinitis due to Cryptococcus neoformans var gattii was diagnosed in a castrated, 5-year-old, albino ferret with subcutaneous swelling of the nasal bridge. The diagnosis was based on histology, needle aspirate cytology and positive culture on Sabouraud's dextrose agar and birdseed agar. The ferret was successfully treated using a long course of itraconazole (25 to 33 mg orally once daily with food) subsequent to surgical debulking of the lesion, using sequential cryptococcal antigen titre determinations to guide therapy.

Animals↗

Head and neck tumors: fractionated frameless stereotactic interstitial brachytherapy-initial experience.

The authors used a frameless stereotactic navigation system, the Vogele-Bale-Hohner head holder, and a targeting device to reproducibly position brachytherapy needles for fractionated interstitial brachytherapy in 12 patients with inoperable cancers of the head and neck. In all cases, deviations of the needle relative to the planned position were within 1-15 mm depending on the location of the tumor.

Brachytherapy↗

The representation of objects in the human occipital and temporal cortex.

Recently, we identified, using fMRI, three bilateral regions in the ventral temporal cortex that responded preferentially to faces, houses, and chairs [Ishai, A., Ungerleider, L. G., Martin, A., Schouten, J. L., & Haxby, J. V. (1999). Distributed representation of objects in the human ventral visual pathway. Proceedings of the National Academy of Sciences, U.S.A., 96, 9379--9384]. Here, we report differential patterns of activation, similar to those seen in the ventral temporal cortex, in bilateral regions of the ventral occipital cortex. We also found category-related responses in the dorsal occipital cortex and in the superior temporal sulcus. Moreover, rather than activating discrete, segregated areas, each category was associated with its own differential pattern of response across a broad expanse of cortex. The distributed patterns of response were similar across tasks (passive viewing, delayed matching) and presentation formats (photographs, line drawings). We propose that the representation of objects in the ventral visual pathway, including both occipital and temporal regions, is not restricted to small, highly selective patches of cortex but, instead, is a distributed representation of information about object form. Within this distributed system, the representation of faces appears to be less extensive as compared to the representations of nonface objects.

Adult↗

Short communication: effects of monensin on 3-methylhistidine excretion in transition dairy cows.

Urinary 3 methyl-histidine excretion was measured in high yielding dairy cows between 10 and 3 d precalving and between 3 and 9 d postcalving. Cows received a sodium monensin controlled-release capsule or a placebo 3 wk before calving. Monensin did not affect urinary 3 methyl-histidine. Average urinary 3 methyl-histidine excretion was significantly higher postcalving (4.11 mmol d(-1)) than precalving (2.48 mmol d(-1)). This increase is assumed to be predominantly due to the negative nitrogen balance in the postcalving period caused by insufficient nutrient intake to meet nutrient requirements, which necessitates catabolism of mainly myofibrillar protein.

Animals↗

Effect of a prepartum administration of monensin in a controlled-release capsule on apparent digestibilities and nitrogen utilization in transition dairy cows.

The influence of a monensin controlled-release capsule, which was administered 3 wk before the calving date, on diet digestibility and nitrogen utilization was investigated in 16 multiparous dairy cows between approximately 10 and 3 d precalving and 3 and 9 d postcalving. Monensin decreased rumen ammonia from 5.4 to 3.2 mg dl(-1) precalving and from 6.0 to 4.9 mg dl(-1) postcalving. Blood urea concentrations were increased by monensin from 4.93 to 5.28 mM precalving and from 5.27 to 5.81 mM postcalving, but these increases were not statistically significant. Precalving, monensin increased the apparent digestibilities of neutral detergent fiber from 52.8 to 62.1%, of acid detergent fiber from 50.7 to 58.7%, and of gross energy from 60.5 to 66.7%. Postcalving, monensin increased the apparent nitrogen digestibility from 63.7 to 71.5%, which resulted in an improvement in the nitrogen balance from -77.8 to -44.9 g d(-1). The monensin controlled-release capsule contributed to increasing the availability of dietary nitrogen to the transition dairy cow during the critical postcalving period.

Ammonia↗

Pharmacotherapy of early-onset depression. Update and new directions.

Although an increased recognition of depressive disorders in youth represents a positive conceptual change over the past decades, there still is a very limited amount of research on useful treatment interventions. The paucity of data is particularly keen for the use of psychotropic drugs. For example, by applying the criteria suggested by the International Psychopharmacology Algorithm Project, there barely are enough first-grade ("Level A," meaning at least two RCTs) data supporting the short-term efficacy of antidepressants (the SSRIs) in the treatment of juvenile depression. And yet, limited data have not translated into limited use in routine clinical practice. In fact, the use of antidepressant medications has increased exponentially over the last decade, a change that is especially conspicuous for individuals less than 18 years of age. The perceived safety of the SSRIs and other novel antidepressants is partly at the root of their increased popularity. Data regarding their safety are likewise quite limited, however, and essentially are nonexistent for longer-term use. Based on the reviewed data, a medication algorithm for the treatment of early-onset depression can be suggested (Fig. 1). The algorithm underscores the need for adequate evaluation and diagnostic assessment, with particular attention to comorbid conditions (such as a bipolar diathesis) that may dictate alternative treatment strategies. In general, psychotherapy is the initial approach to juvenile MDD, with medication use reserved for more severe cases or those not responding to psychotherapy alone. Given that only two types of psychotherapy and two SSRIs have adequate controlled short-term efficacy data, all but the initial steps must be undertaken guided by clinical judgment and an individualized risk-benefit analysis. An algorithm such as this one, based on the very limited efficacy and safety data available, may be viewed as setting priorities for a comprehensive research agenda, more than dictating rigid treatment guidelines. In closing, it can be suggested that future research on the pharmacotherapy of early-onset depressive disorder pay particular attention to the following three aspects: 1. Too many drugs, too few data: Rapid advances in drug development have led to a plethora of available antidepressant agents. It is clear that there are many more agents available than can be adequately studied at present. Because many such agents are mechanistically similar, if not identical, it may be wise to focus research efforts on truly novel agents, particularly those (such as the CRH receptor antagonists, or those affecting neurosteroidogenesis) whose action is based on preclinical and clinical pathophysiologic disease paradigms. 2. Longitudinal follow-up and maintenance studies: Essentially all reviewed treatment studies have been short-term trials. There is a marked paucity of longer-term follow-up data, or of naturalistic and "real-world" effectiveness studies. For example, one of the few studies addressing maintenance pharmacotherapy for early-onset depression has demonstrated surprisingly high recurrence rates, even for those subjects actively on maintenance medication. 3. Long-term safety: Clinicians and parents alike often face difficult decisions regarding the long-term exposure of antidepressant drugs on the developing brain. Although no definitive long-term safety data are likely to become available anytime soon, real risks, such as suicide, and potential sequelae of long-term exposure to the underlying illness itself need all to be part of any decision-making process. Preclinical studies have shown that brain-derived neurotrophic factor (BDNF) levels can be upregulated by antidepressants, and low BDNF factors have been associated with atrophic brain changes in recurrent forms of adult MDD. Although these observations require specific application to juvenile forms of the disorder, they raise the exciting prospect that the natural course of the illne

Adolescent↗

Research Units on Pediatric Psychopharmacology (RUPP) Autism Network. Background and rationale for an initial controlled study of risperidone.

This article has reviewed the background and rationale for the choice of risperidone as the first drug to be studied by the RUPP Autism Network. Risperidone has potent effects on 5-HT and DA neuronal systems, both of which have been implicated in the pathophysiology of autism. Unlike the typical antipsychotics, haloperidol and pimozide, which have been shown to be effective for reducing many of the maladaptive behaviors associated with autism, risperidone's 5-HT2A/DA D2 ratio of receptor blockade appears to produce a lower risk of acute and chronic extrapyramidal side effects, as well as enhanced efficacy for the "negative" symptoms of autism. Indirect clinical and preclinical evidence supports the use of risperidone to treat impaired social behavior, interfering repetitive phenomena, and aggression, targets of pharmacotherapy for many patients with autism. Numerous published open-label trials in children and adolescents with autism and related PDDs and one double-blind, placebo-controlled study in adults suggest that risperidone has promise for the treatment of children and adolescents with autism. Because most of these studies have been short-term, open-label trials in small samples, however, a large-scale controlled study of risperidone in children and adolescents with autism is needed to confirm these results. Finally, because it is likely that children who demonstrate short-term benefit from risperidone will remain on the medication indefinitely, the longer-term effectiveness and safety of risperidone in this population also needs to be determined. The design of this study and the assessments used are described separately.

Adolescent↗

Changes in baroreceptor sensitivity for heart rate during normotensive pregnancy and the puerperium.

Normal pregnancy is associated with marked changes in cardiovascular haemodynamics, which in part may be due to changes in autonomic control mechanisms. Baroreflex sensitivity for heart rate (BRS) was calculated in the supine and standing positions using power spectral analysis of pulse interval (PI) and systolic blood pressure (SBP) in 16 normotensive pregnant women and 10 normotensive non-pregnant controls. The pregnant women were studied on three occasions during their pregnancy (early, mid- and late gestation) and once during the puerperium. Supine total SBP variability increased between early and late pregnancy by 79% [95% confidence intervals (CI) 30%, 145%; P<0. 001], and supine high-frequency PI variability decreased by 75% (CI 51%, 88%; P<0.001). Supine BRS fell by 50% (P<0.001), with values returning to early-pregnancy levels in the puerperium, which were similar to those recorded in the control group. Standing SBP variability and BRS values were unchanged during pregnancy and post partum. The low/high frequency ratio of PI variability, taken as a surrogate measure of sympathovagal balance, increased by 137% (CI 42%, 296%; P<0.01) in the supine but not the standing position from early to late pregnancy. This was due to a decrease in high-frequency variability rather than to an increase in low-frequency variability, suggesting that these changes may have been due to vagal withdrawal rather than increased sympathetic activity. Normotensive pregnancy is associated with a marked decrease in supine BRS, although the exact mechanisms for these changes remain unclear. Further studies are required to define whether changes in BRS and sympathovagal tone in early pregnancy can be used to predict the onset of pregnancy-induced hypertension.

Adolescent↗

The use of psychotropic medications in young children: the facts, the controversy, and the practice.

There has been recent concern by the public and physicians alike over reports that increasing numbers of young children are being prescribed psychotropic medications. The report by Zito and colleagues addressing this subject that appeared in the 23 February 2000 issue of JAMA sparked enormous controversy and was the impetus for a White House Conference just one month in its wake (20 March 2000). State and federal agencies have considered legislation to regulate the practice of prescribing psychotropic medications to preschool children. Special aspects of the use of psychotropic medication in preschool children are reviewed, with recommendations for evaluation and treatment decisions. The need for data and research in this area is highlighted.

Age Factors↗

Investigation of anthropometric and work-rate profiles of elite South American international soccer players.

BACKGROUND: The aim of the current investigation was to determine the movement profiles of elite South American soccer players during international competition and examine the relationship between anthropometric profile and work-rate variables. METHODS: Seventeen full-time professional soccer players were filmed while competing for their countries. Anthropometric profiles were obtained for eleven of these players. Six full-time professional players from the English Premier League were also filmed for comparative purposes. RESULTS: The South American international players covered significantly less (p<0.05) total distance during match-play than English Premier League players (International, 8638+/-1158 m; English Premier League, 10104+/-703 m). The total distance covered during the second half of the game was significantly reduced (p<0.05) compared to the first half distance for both groups of players (mean+/-SD first half 4605+/-625 m; mean+/-SD second half 4415+/-634 m). The data for both groups of players were combined to evaluate positional differences in the workrate profile. Midfield players covered a significantly greater (p<0.05) distance than forward players (midfield, 9826+/-1031 m; forwards, 7736+/-929 m) and defenders covered a greater (p<0.05) distance jogging backwards than forward players (defenders, 276+/-155 m; forwards, 68+/-25 m). Forwards sprinted a greater distance (p<0.05) than defensive players (defenders, 231+/-142 m; forwards, 557+/-142 m). Mean somatotype was a balanced mesomorph (2-5 1/2-2). Body mass and muscle mass was related to the total distance covered (r=0.43, r=0.53, p<0.05). CONCLUSIONS: Based on these data, it seems that an individual's work-rate profile is dependent upon the type of competition and the playing position. Relationships between anthropometric profile and work-rate are complex due to the interaction between the variables that determine work-rate.

Adult↗

A knowledge-based patient assessment system: conceptual and technical design.

This paper describes the design of an inpatient patient assessment application that captures nursing assessment data using a wireless laptop computer. The primary aim of this system is to capture structured information for facilitating decision support and quality monitoring. The system also aims to improve efficiency of recording patient assessments, reduce costs, and improve discharge planning and early identification of patient learning needs. Object-oriented methods were used to elicit functional requirements and to model the proposed system. A tools-based development approach is being used to facilitate rapid development and easy modification of assessment items and rules for decision support. Criteria for evaluation include perceived utility by clinician users, validity of decision support rules, time spent recording assessments, and perceived utility of aggregate reports for quality monitoring.

Artificial Intelligence↗

Effect of vitamin E intake on levels of vitamins E and C in the central nervous system and peripheral tissues: implications for health recommendations.

Vitamin E (alpha-gamma-tocopherol) is an important component in biological membranes. A decrease in its concentration imposes structural and functional damage to the cells. The object of this study was to assess the effect of a graded dietary vitamin E (E) intake on E concentration in specific regions of the brain, and its influence on vitamin C levels and neurological function. Following a 2-month period, rats supplemented with 5, 30, 60, 250 or 500 mg all-rac-alpha-tocopherol-acetate/kg diet (mg E/kg diet) exhibited a significant increase of E concentration in brain and peripheral tissues. However, while blood and liver showed a dose response increase in E concentration which correlated well with the different levels of E in the diet, the central nervous system (CNS) followed the same pattern of increase of vitamin E in brain tissue only when the diet was supplemented with 5, 30, or 60 mg E/kg diet. No further increase in E concentration was observed when the diet was supplemented with 250 or 500 mg E/kg diet. Similarly, the heart tissue showed a significant increase in its E concentration when the was enriched with 5, 30, or 60 mg E/kg diet, with no further increases at 250 or 500 mg. Vitamin C concentration in brain cortex and cerebellum, plasma, liver, and heart was reduced in the groups receiving 250 or 500 mg E/kg diet. Compared to the low E group, rats supplemented with the 60, 250 or 500 mg E/kg diet showed a significant enhancement in striatal dopamine (DA) release, but no differences were observed among the latter three groups.

Animals↗

[Nutriceuticals].

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Dietary Supplements↗

Are face-responsive regions selective only for faces?

To examine the specificity of face-responsive regions for face processing, we used fMRI to measure the response of the fusiform gyrus and the superior temporal sulcus (STS) to pictures of human faces, animals, faceless animals, and houses. Results indicate that faces, animals, and faceless animals all elicited greater activity than houses, and had identical peaks of activation in the lateral fusiform gyrus, bilaterally, and in the right posterior STS. Moreover, within the lateral fusiform gyrus the responses to faces, animals and faceless animals were all greater than the responses to these stimuli in the medial aspect of the fusiform gyrus, a region that responds more strongly to other objects (e.g. houses). These findings suggest that the neural representation of animals in the fusiform gyrus and the posterior STS relies strongly on the same neural substrates that represent faces.

Adult↗

Reversals of age-related declines in neuronal signal transduction, cognitive, and motor behavioral deficits with blueberry, spinach, or strawberry dietary supplementation.

Ample research indicates that age-related neuronal-behavioral decrements are the result of oxidative stress that may be ameliorated by antioxidants. Our previous study had shown that rats given dietary supplements of fruit and vegetable extracts with high antioxidant activity for 8 months beginning at 6 months of age retarded age-related declines in neuronal and cognitive function. The present study showed that such supplements (strawberry, spinach, or blueberry at 14.8, 9.1, or 18.6 gm of dried aqueous extract per kilogram of diet, respectively) fed for 8 weeks to 19-month-old Fischer 344 rats were also effective in reversing age-related deficits in several neuronal and behavioral parameters including: oxotremorine enhancement of K(+)-evoked release of dopamine from striatal slices, carbachol-stimulated GTPase activity, striatal Ca(45) buffering in striatal synaptosomes, motor behavioral performance on the rod walking and accelerod tasks, and Morris water maze performance. These findings suggest that, in addition to their known beneficial effects on cancer and heart disease, phytochemicals present in antioxidant-rich foods may be beneficial in reversing the course of neuronal and behavioral aging.

Aging↗

Distributed representation of objects in the human ventral visual pathway.

Brain imaging and electrophysiological recording studies in humans have reported discrete cortical regions in posterior ventral temporal cortex that respond preferentially to faces, buildings, and letters. These findings suggest a category-specific anatomically segregated modular organization of the object vision pathway. Here we present data from a functional MRI study in which we found three distinct regions of ventral temporal cortex that responded preferentially to faces and two categories of other objects, namely houses and chairs, and had a highly consistent topological arrangement. Although the data could be interpreted as evidence for separate modules, we found that each category also evoked significant responses in the regions that responded maximally to other stimuli. Moreover, each category was associated with its own differential pattern of response across ventral temporal cortex. These results indicate that the representation of an object is not restricted to a region that responds maximally to that object, but rather is distributed across a broader expanse of cortex. We propose that the functional architecture of the ventral visual pathway is not a mosaic of category-specific modules but instead is a continuous representation of information about object form that has a highly consistent and orderly topological arrangement.

Adult↗