An association for patient-oriented research

Physician-scientists, who study the pathogenesis of disease by using both bedside observations and modern laboratory techniques, are decreasing in number. Ideally, in any profession, some members are devoted to developing its scholarly basis; in contrast, technologists perform activities derived from the work of scientists or scholars. Therefore, the decreasing number of physician-scientists may cause medicine to become a technology rather than a profession. This atrophy in patient-oriented research is caused in part by the current state of laboratory science: Discoveries that are not generated from clinical observations often elucidate many aspects of disease. Furthermore, economic necessities have impelled research-oriented physicians to choose between delivery of health care and performance of basic laboratory science. This paper discusses the continuing need for detailed observation of human disease as a driving force in the development of biomedical science, which combines clinical and laboratory observations. To further the development of this field, the Association for Patient-Oriented Research has been founded. This association will be a new forum in which physician-scientists can present their work and encourage other physicians to join in the research endeavor.

A Streptococcus pyogenes outbreak caused by an unusual serotype of low virulence: the value of typing techniques in outbreak investigations

OBJECTIVES

To investigate and stop the spread of an outbreak of Streptococcus pyogenes infection in a district general hospital, involving 19 patients and two nurses over a 20-day period.

METHODS

All suspected persons were investigated using conventional bacteriological techniques, followed by M, T and exotoxin gene-typing of the isolates in a national reference laboratory.

RESULTS

11 patients and both nurses were associated with the acute surgical ward on one floor of the hospital. They were infected with serotype M 9/T B3264, a strain with apparently low virulence, which has not been previously associated with outbreaks. Two other patients on the same floor each had different types and there were two clusters of another S. pyogenes serotype on other floors, each involving two patients. Two (unrelated) patients yielded other types of S. pyogenes. The patients were not seriously ill but had some delay in wound healing.

CONCLUSIONS

The value of typing the isolates of S. pyogenes in this outbreak was in defining which patients were involved. No added value could be ascribed to the exotoxin gene-typing results.

A double interaction screen identifies positive and negative ftz gene regulators and ftz-interacting proteins

Regulatory genes directing embryonic development are expressed in complex patterns. The Drosophila homeobox gene fushi tarazu (ftz) is expressed in a striped pattern that is controlled by several discrete and large cis- regulatory elements. One key cis-element is the ftz proximal enhancer which is required for stripe establishment and which mediates autoregulation by direct binding of Ftz protein. To identify the trans-acting factors that regulate ftz expression and autoregulation, we developed a modified yeast two hybrid screen, the Double Interaction Screen (DIS). The DIS was designed to isolate both DNA binding transcriptional regulators that interact with the proximal enhancer and proteins that interact with Ftz itself when it is bound to the enhancer. The screen identified two candidate Ftz protein cofactors as well as activators and repressors of ftz transcription that bind directly to the enhancer. One of these (Tramtrack (Ttk)) was previously shown to bind to at least five sites in the proximal enhancer; genetic studies suggested that Ttk acts as a repressor of ftz in the embryo. Here we show that, in yeast cells, Ttk protein strongly activates transcription, suggesting that yeast may be missing a necessary co-repressor which is present in Drosophila embryos. Further, we have characterized the activity of a second candidate ftz repressor isolated in the screen - the product of the pair-rule gene sloppy paired - a member of the forkhead family. We show that Slp1 is a DNA binding protein. We have identified a high affinity binding site for Slp1 in the ftz proximal enhancer. Slp1 represses transcription via this binding site in yeast cells, consistent with its role as a direct repressor of ftz stripes in interstripe regions during late stages of embryogenesis. The DIS should be a generally useful method to identify DNA binding transcriptional regulators and protein partners of previously characterized DNA binding proteins.

Human obesity: a sufficient cause

It is sometimes useful to group the causes for any biological event into those that are necessary and those that are sufficient. Our current, partial understanding of human obesity has come through a focus on readily accessible necessary causes. The sufficient causes are likely to be more complex, dealing with the integration of developmental events, behavior and complex biochemical systems.

Brain mapping in sedated infants and young children with passive-functional magnetic resonance imaging

Functional magnetic resonance imaging (fMRI) in pediatric patients presents a unique set of problems due to the need for patient compliance, the frequent need for sedation and an early developmental status. A new method for using fMRI in sedated infants and young children is presented using passive stimuli focused on visual, sensorimotor and language functions. All of these stimuli are presented such that no patient interaction is required. Eight sedated children undergoing diagnostic MRI scans of the brain participated in these passive fMRI procedures. Cortical regions were identified using standard techniques applied to the blood-oxygen-level-dependent signal which is the basis for fMRI. The results support the feasibility of brain mapping in sedated children with passive fMRI techniques.

Representation of nociceptive stimuli in primary sensory cortex

Using fMRI, we observed cortical activity associated with nociceptive hot and cold sensations applied to hand and foot that are not spatially restricted to the corresponding regions of the primary somatosensory cortex (SI). Hot (55-57 degrees C) and cold (0-2 degrees C) tactile stimuli were applied separately to the right hand and foot of eight right-handed subjects. Although somatotopic mapping of hand and foot was observed as expected based on the Penfield homunculus, activations associated with hot during both hand and foot stimulation and subsequently, cold, activated regions unique to each thermal modality irrespective of the body part. This distributed system for thermal information is present at both nociceptive and more neutral thermal intensities (i.e. warm and cool sensations) indicating the presence of distributed sensory processing associated with thermal-related sensations in human primary sensorimotor cortex.

Improved synthesis of an aldobiouronic acid related to hardwood xylans, and preparation of a derivative thereof suitable for linking to proteins

Treatment of 1,3,4-tri-O-acetyl-alpha-D-xylopyranose with methyl 2,3-di-O-benzyl-l-chloro-l-deoxy-4-O-methyl-alpha, beta-D-glucopyranuronate in the presence of silver trifluoromethanesulfonate was highly stereoselective to give the alpha-linked aldobiouronic acid derivative (4) in 86% yield, after hydrogenolysis of the crude product of the coupling and chromatography. Compound 4 was acetylated and the fully protected substance was converted to the corresponding glycosyl chloride. Reaction of the latter with p-nitrophenol under phase-transfer catalysis afforded, after deacetylation, p-nitrophenyl 2-O-(methyl 4-O-methyl-alpha-D-glucopyranosyluronate)-beta-D-xylopyranoside.

[Glutamatergic excitatory receptors and temporal lobe epilepsy]

Despite a considerable wealth of data, the mechanisms responsible for the generation of epileptic bursts in temporal lobe epilepsy (TLE) remain a mystery. Recently, research and therapy have focused on impairment of GABAergic inhibition in epilepsy. Several lines of evidence support this approach: 1-GABA is the main inhibitory neurotransmitter in the neuronal structures involved in TLE. 2-Enhancers of GABAergic inhibition (such as benzodiazepines or barbiturates) are commonly used as antiepileptic drugs. 3-Interictal discharges can be obtained following the pharmacological blockade of GABAA receptors. Since the axiom at the basis of epilepsy research states that the balance between inhibition and excitation is tipped toward excitation, we have addressed the following question: where are the loci most likely to be involved in such imbalance? We have limited our investigation to the excitatory side of the story. The main glutamatergic excitatory receptors (AMPA and NMDA) involved in TLE and their properties will be first addressed. We will focus on the excitatory synapses most likely involved in epileptogenesis. We have then specifically studied the effects of redox reagents on NMDA receptor-dependent epileptiform activity in a chronic animal model of TLE, the kainic acid lesioned rat hippocampus. We report that oxidizing drugs abolish evoked epileptiform discharges via a decrease by 50 p. 100 of NMDA receptor-mediated responses without affecting synaptic plasticity and thus memory and learning. The dormant cell hypothesis (i.e. the disconnection of inhibitory interneurons from their excitatory afferents) was also tested. We report that interneurons are not dormant in TLE and fire bursts of action potentials during spontaneous or evoked paroxismal activity.

Human fatty acid synthesis is reduced after the substitution of dietary starch for sugar

Using new nonisotopic and isotopic methods, we showed previously that fatty acid synthesis was markedly stimulated in weight-stable normal volunteers by a very-low-fat formula diet with 10% of energy as fat and 75% as short glucose polymers. In this study, we determined whether fatty acid synthesis was equally stimulated by a very-low-fat solid diet made with foods consumed typically. Four normal volunteers consumed the same very-low-fat formula diet for 25 d and then an isoenergetic solid food diet with 10% of energy as fat and 75% as starch, simple sugars, and fiber for 25 d. To measure fatty acid synthesis, the fatty acid compositions of the diets were matched to the composition of each subject's adipose tissue and compared with the composition of VLDL-triacylglycerol. In all subjects, the large increases in newly formed palmitate and decreases in linoleate in VLDL-triacylglycerol were quickly reversed by the solid food diet, and the fraction of de novo synthesized fatty acids in fasting VLDL-triacylglycerol decreased from 30-54% to 0-1%. In a second group of subjects, the stimulation of fatty acid synthesis by the formula diet with 75% glucose polymers was similarly reduced by a formula diet with amounts of fat, starch, and sugar chosen to mimic those of the solid food diet, but persisted after the addition of fiber or a diet with 75% sugar. In conclusion, an increase in fatty acid synthesis and palmitaterich, linoleate-poor VLDL-triacylglycerol induced by very-low-fat, high-sugar diets may be reduced by the substitution of dietary starch for sugar with potentially beneficial effects on cardiovascular health.

The genetics of obesity

Five genes have been identified, each capable of causing obesity in mice and each with a human homologue. One of them codes for a signal expressed by adipose tissue, and another for the signal's brain receptor. The rest reveal brain pathways probably downstream from the receptor. Together, the genes offer glimpses of an intricate system that defends adipose stores--and in some persons maintains an unhealthful set-point.

Diet composition and energy balance in humans

Inpatient metabolic studies of human subjects were performed to obtain data on important nutritional issues. It was shown that wide variations in the ratio of carbohydrate to fat do not alter total 24-h energy need. Studies of the fatty acid composition of plasma low-density lipoproteins during low-fat feeding indicated that there can be considerable lipogenesis from carbohydrate in humans during isoenergetic feeding. The energy cost of this conversion must be small or be counterbalanced by other changes in energy metabolism because measured energy need was unaltered by fat-to-carbohydrate ratios. Energy need was, however, markedly varied by changes in body weight. Subjects at their usual body weights who had experimentally induced increases in body weight became inefficient and required a higher energy intake for weight maintenance. The reverse occurred with a reduction in body weight. The set point at which energy storage is defended is clearly different in obese persons.

Some history of heredity-vs-environment, genetic inferiority at Harvard (?), and The (incredible) Bell Curve

This article discusses some historical and intellectual roots of American behaviorism in psychology and its anti-heredity, environmentalist bias, as well as the early 'justification' for pure line theory in genetics and some interrelations between the two fields. Next, I discuss the heritability concept, its promotion, its critique and the importance of distinguishing it from, rather than confusing or conflating it with, the heredity concept. Then, briefly I consider some of the history and problems associated with the intelligence concept, as well as the capital importance of biological controls in studies of human heredity. And finally, I document the incredibility of the The Bell Curve and the appalling inadequacy of its reception.

Effects of weight change on plasma leptin concentrations and energy expenditure

Circulating concentrations of leptin are closely correlated with body fat mass, and may thus constitute an afferent limb of a system regulating body fatness, with efferent limbs that affect energy expenditure and food intake. We studied 50 subjects (27 males, 23 premenopausal females; 31 never-obese, 19 obese) at usual body weight during active weight loss or weight gain and during the maintenance of body weights 10% above usual (WT + 10%) and 10% and/or 20% below usual body weight (Wt -10% and Wt -20%) to test the hypotheses that the dynamic process of weight change and the maintenance of an altered body weight are associated with significant changes in circulating concentrations of leptin and/or the relationship between fat mass and leptin, and such changes in the plasma concentration of leptin are related to changes in energy expenditure at altered body weight. Subjects were admitted to the Rockefeller University Hospital, and energy metabolism (24-h energy expenditure, resting energy expenditure, thermic effect of feeding, and nonresting energy expenditure) and circulating concentrations of leptin and insulin were examined at various weight plateaus (usual body weight, 10% above usual body weight, 10% below usual body weight, and 20% below usual body weight). Plasma leptin was also measured in some subjects during dynamic periods of weight gain or loss. Though both plasma leptin concentrations and fat mass were significantly correlated with resting energy expenditure, only the correlation of fat mass and energy expenditure remained significant in a multiple stepwise linear regression analysis. Neither absolute nor relative changes in plasma leptin between weight plateaus were significantly correlated with any of the observed changes in energy expenditure. Plasma leptin concentrations were significantly lower during weight loss than during weight maintenance at the same body composition. Plasma leptin concentrations, normalized to fat mass, were significantly lower during the maintenance of a reduced body weight in females and higher during the maintenance of an elevated body weight in males than in the same subjects at usual body weight. At all weight plateaus, plasma leptin concentrations normalized to fat mass were significantly higher in females than in males, but gender was not a significant covariate of the relationship between leptin and energy expenditure. Postabsorptive serum concentrations of insulin was a significant covariate of plasma leptin concentration in males, but not females, at Wt initial and Wt + 10%. Although plasma leptin is significantly reduced during dynamic weight loss compared with static weight maintenance at the same body weight, the lack of correlation between changes in plasma leptin and changes in energy expenditure between weight plateaus suggests that leptin is not the primary signal that mediates the changes of energy expenditure that accompany the maintenance of an altered body weight in humans.

Attenuation of IL-5-mediated signal transduction, eosinophil survival, and inflammatory mediator release by a soluble human IL-5 receptor

A soluble form of the human IL-5R alpha-chain (IL-5Ra) that contains the extracellular IL-5 binding domain has been evaluated for its effect on IL-5 binding to and activation of human eosinophils and basophils. The truncated receptor was expressed in Escherichia coli and recovered in biologically active form following renaturation and anion exchange chromatography. The soluble receptor formed a 1/1 complex with IL-5 in solution and bound IL-5 with affinity comparable to that of cell-associated IL-5Ra. Soluble IL-5Ra also competed with IL-5 for binding to the native alpha beta IL-5R on human cells and inhibited IL-5-mediated receptor activation and inflammatory mediator production. In this regard, the soluble receptor prevented IL-5-induced tyrosine phosphorylation of JAK2 kinase and IL-5R beta-chain and inhibited IL-5 priming of leukotriene C4 release by human basophils. However, the E. coli-derived receptor failed to inhibit IL-5 in longer term assays, including eosinophil survival and TF-1 cell proliferation, possibly due to its propensity to aggregate in a time- and temperature-dependent manner. In contrast, we observed that a soluble IL-5Ra derived from baculovirus-infected cells was less prone to aggregate and effectively antagonized IL-5-induced cell proliferation and survival. These findings indicate that the extracellular portion of the human IL-5Ra chain can prevent association of IL-5 with cell surface receptors and can attenuate signal transduction, mediator release, and survival of inflammatory cells. As such, soluble IL-5R may be useful in treating diseases such as human asthma, in which pulmonary injury is associated with the activity of IL-5R-bearing cells.

Attenuation of IL-5-mediated signal transduction, eosinophil survival, and inflammatory mediator release by a soluble human IL-5 receptor

A soluble form of the human IL-5R alpha-chain (IL-5Ra) that contains the extracellular IL-5 binding domain has been evaluated for its effect on IL-5 binding to and activation of human eosinophils and basophils. The truncated receptor was expressed in Escherichia coli and recovered in biologically active form following renaturation and anion exchange chromatography. The soluble receptor formed a 1/1 complex with IL-5 in solution and bound IL-5 with affinity comparable to that of cell-associated IL-5Ra. Soluble IL-5Ra also competed with IL-5 for binding to the native alpha beta IL-5R on human cells and inhibited IL-5-mediated receptor activation and inflammatory mediator production. In this regard, the soluble receptor prevented IL-5-induced tyrosine phosphorylation of JAK2 kinase and IL-5R beta-chain and inhibited IL-5 priming of leukotriene C4 release by human basophils. However, the E. coli-derived receptor failed to inhibit IL-5 in longer term assays, including eosinophil survival and TF-1 cell proliferation, possibly due to its propensity to aggregate in a time- and temperature-dependent manner. In contrast, we observed that a soluble IL-5Ra derived from baculovirus-infected cells was less prone to aggregate and effectively antagonized IL-5-induced cell proliferation and survival. These findings indicate that the extracellular portion of the human IL-5Ra chain can prevent association of IL-5 with cell surface receptors and can attenuate signal transduction, mediator release, and survival of inflammatory cells. As such, soluble IL-5R may be useful in treating diseases such as human asthma, in which pulmonary injury is associated with the activity of IL-5R-bearing cells.

Fast and localized event-related optical signals (EROS) in the human occipital cortex: comparisons with the visual evoked potential and fMRI

Localized evoked activity of the human cortex produces fast changes in optical properties that can be detected noninvasively (event-related optical signal, or EROS). In the present study a fast EROS response (latency approximately 100 ms) elicited in the occipital cortex by visual stimuli showed spatial congruence with fMRI signals and temporal correspondence with VEPs, thus combining subcentimeter spatial localization with subsecond temporal resolution. fMRI signals were recorded from striate and extrastriate cortex. Both areas showed EROS peaks, but at different latencies after stimulation (100 and 200-300 ms, respectively). These results suggest that EROS manifests localized neuronal activity associated with information processing. The temporal resolution and spatial localization of this signal make it a promising tool for studying the time course of activity in localized brain areas and for bridging the gap between electrical and hemodynamic imaging methods.

The coming of genetics in the control of ingestion

The study of appetitive behavior in relation to obesity is now being enriched by molecular-genetic findings in experimental animals with genetic obesity and associated "feeding disorders". The opinion is expressed that the mutual enrichment of the disciplines of behavior and molecular biology will place the study of human ingestive behavior on a firm scientific base.

Distinct cortical areas associated with native and second languages

The ability to acquire and use several languages selectively is a unique and essential human capacity. Here we investigate the fundamental question of how multiple languages are represented in a human brain. We applied functional magnetic resonance imaging (fMRI) to determine the spatial relationship between native and second languages in the human cortex, and show that within the frontal-lobe language-sensitive regions (Broca's area), second languages acquired in adulthood ('late' bilingual subjects) are spatially separated from native languages. However, when acquired during the early language acquisition stage of development ('early' bilingual subjects), native and second languages tend to be represented in common frontal cortical areas. In both late and early bilingual subjects, the temporal-lobe language-sensitive regions (Wernicke's area) also show effectively little or no separation of activity based on the age of language acquisition. This discovery of language-specific regions in Broca's area advances our understanding of the cortical representation that underlies multiple language functions.

Cardiac autonomic nervous system activity in obese and never-obese young men

Autonomic nervous system (ANS) activity in age-matched, weight-stable, free-living, ad libitum-fed, obese (OB) and never-obese (NO) young men (body mass index means [SD], 38.5 [3.9] and 22.0 [1.7], respectively) was evaluated by sequential blockade of cardiac autonomic innervation with weight-adjusted doses of parasympathetic (atropine) and sympathetic (esmolol) blockers so as to produce maximal effects on heart rate. Change in heart period (interbeat interval) from baseline, induced by atropine, defined parasympathetic control (PC), and the subsequent change, after esmolol administration, defined sympathetic control (SC). The heart period, after PC and SC blockade, defined intrinsic heart period (I). In the OB group, baseline heart period and PC were lower, and SC and I were higher, than in the NO group. The results in the OB, relative to the NO subjects, are similar to those reported in a previous study of NO subjects who had undergone a 10% weight gain by overfeeding. These findings suggest that the ANS of individuals with obesity is chronically altered in a way that would tend to oppose their excessive adiposity, and that these autonomic changes are more likely to be responses to other forces that induce obesity, rather than being primary agents in the production of the disease.

Phase II randomized trial of gallium nitrate plus fluorouracil versus methotrexate, vinblastine, doxorubicin, and cisplatin in patients with advanced transitional-cell carcinoma

PURPOSE

A phase II randomized trial of gallium nitrate/fluorouracil (5-FU) versus dose-intense methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) was performed in poor-risk patients with advanced urothelial tract tumors. The efficacy and toxicity of these regimens were compared. Assessment of dose-intense M-VAC as salvage treatment in patients who failed to respond to the gallium nitrate/5-FU regimen was also performed.

PATIENTS AND METHODS

Thirty-four patients who had not received prior systemic chemotherapy were randomized to either arm of the study. All patients had one or more clinical features predicting a low likelihood of durable complete response to standard chemotherapy, ie, weight loss, visceral metastases, and low performance status. Gallium nitrate and 5-FU were each administered by continuous 5-day infusions every 28 days. M-VAC was recycled every 21 days, with prophylactic recombinant human granulocyte colony-stimulating factor (rh-G-CSF).

RESULTS

Two of 17 patients (12%; 95% confidence interval [CI], 1.4% to 36.4%) had a major response to gallium nitrate/5-FU. Sixteen of 17 patients treated with M-VAC (94%; 95% CI, 71.3% to 99.8%) demonstrated a major response. Five of 12 patients who failed to respond to the gallium nitrate/5-FU combination responded to M-VAC as second-line therapy (42%; 95% CI, 15.2% to 72.3%). Median survival for the gallium nitrate and 5-FU arm was 19 versus 17 months for the M-VAC arm, with a median follow-up duration of 35 months (range, 2 to 51) for all patients. Dose-intense M-VAC was associated with a greater incidence of neutropenia and thrombocytopenia.

CONCLUSION

Dose-intense M-VAC is superior to gallium nitrate/5-FU in poor-risk patients (P < .0001). Despite the overall high response rate, the median survival for patients with M-VAC remained unsatisfactory. Similar survival distributions were observed for patients who received investigational therapy followed by cisplatin-based therapy and patients treated with initial cisplatin-based therapy.

Perception of a border defined by rapidly reversing luminance contrast

We report a new visual illusion of a perceptual boundary visible between two contiguous regions of equal luminance when the intensity is modulated with a temporal frequency that is higher than the critical fusion rate. Measurements of the luminance threshold of the perceptual border with various slopes of the luminance gradient yielded a function suggestive of the range of ocular instability. These findings raise the possibility that this new border illusion may be influenced by involuntary ocular motion during fixation.

Y-chromosome effects on Drosophila geotaxis interact with genetic or cytoplasmic background

Previously, all of the major fruit fly, Drosophila melanogaster, chromosomes (I, II and III) have been shown to be associated with geotaxis, but the Y chromosome has not. Using two methods (back-crossing and chromosome substitution), Y chromosomes from lines that have evolved stable, extreme expressions of geotaxis were placed into different genetic and cytoplasmic backgrounds to test the resulting males for geotaxis. The results of the back-crossing do not support the interpretation of Y-chromosome effects on geotaxis. These tests do not have sufficient statistical power, however, to detect small genetic effects. In the chromosome substitution experiment, the geotaxis-line Y chromosomes were placed into high- and low-selected lines, Canton-S and Champaign wild-type backgrounds. The results of the chromosome substitution experiment provide evidence for a Y-chromosome effect on geotaxis in selected geotaxis lines, but not in wild-type stock, backgrounds. These results suggest that the Y chromosome has a small effect on geotaxis, whose detection depends on genetic and/or cytoplasmic background. The implications of these results are discussed for behaviour genetic analysis of D. melanogaster and for issues of statistical power in detecting small genetic effects.

Fatty acid composition of adipose tissue, an indication of dietary fatty acids, and breast cancer prognosis

PURPOSE

Fatty acid composition of adipose tissue is an indicator of the long-term ingestion pattern of several specific fatty acids. There is good correlation of antecedent diet with the essential fatty acids, and there is reflection of the diet with the fatty acids that can be synthesized. The relationship between the fatty acid levels and lymph node status and clinical outcome was examined.

METHODS

At the time of diagnostic surgery, 161 women with clinical stage T1NO breast cancer had subcutaneous adipose tissue (breast and abdominal) aspirated. The concentrations of 35 fatty acids, seven summed classes, and six fatty acid groups were measured by capillary gas chromatography. Lymph node status was determined with axillary dissection, and patients were followed-up (mean, 7.3 years) for clinical outcome.

RESULTS

There was no significant association of any adipose tissue fatty acids with overall survival, although few (16 of 161 women) died of breast cancer. However, the odds of having positive lymph nodes (57 of 161 women) were significantly higher for women with a greater adipose tissue proportion of oleic acid (odds ratio [OR], 7.56; 95% confidence interval [CI], 1.78 to 32.1) or total saturated acids (OR, 8.43; 95% CI, 1.48 to 40.0) and significantly lower with a higher proportion of trans fatty acids (OR, 0.24; 95% CI, 0.07 to 0.77), as assessed by multivariate logistic regression.

CONCLUSION

These data support previous research with dietary questionnaire methodology, suggesting that specific dietary fatty acids may be associated with breast cancer promotion. Further research with long-term clinical follow-up is necessary to investigate these observations in large, diverse populations before dietary recommendations can be envisioned.

The beta-D-xylosidase of Trichoderma reesei is a multifunctional beta-D-xylan xylohydrolase

An extracellular multifunctional beta-D-xylan xylohydrolase, previously described as beta-xylosidase, was purified from Trichoderma reesei RUT C-30 to physical homogeneity. The active enzyme was a 100 (+/-5) kDa glycosylated monomer that exhibited a pl of 4.7. Its activity was optimal at pH 4 and it was stable between pH 3 and 6. Its temperature-stability was moderate (70 degrees zero of activity remaining after 60 min at 50 degrees C) and optimal activity was observed at 60 degrees C. It is capable of hydrolysing beta-1.4-xylo-oligosaccharides [degree of polymerization (DP) 2-7], the apparent Vmax increasing with increasing chain length. The enzyme also attacked debranched beech-wood (Lenzing) xylan and 4-O-methylglucuronoxylan, forming xylose as the only end product. The K(m) for xylan was 0.7 g/l. For this reason we consider the enzyme to be a beta-D-xylan xylohydrolase. The enzyme also exhibits alpha-L-arabinofuranosidase activity on 4-nitrophenyl alpha-L-arabinofuranoside, and evidence is presented that this is not caused by an impurity in the enzyme preparation. The beta-D-xylan xylohydrolase exhibits glycosyltransferase activity with xylo-oligosaccharides and at high concentrations of 4-nitrophenyl beta-D-xylopyranoside (4-Nph-beta-Xyl). The enzyme hydrolyses beta-1, 4-linkages preferentially to beta-1,3-linkages, and beta-1,2-linked xylo-oligosaccharides are not hydrolysed at all. The enzyme liberates terminal beta-1,4-xylopyranose residues linked to a 2-O-substituted xylopyranose residue, but not that linked to a 3-O-substituted xylopyranose residue. The enzyme does not attack methyl, methyl 1-thio-benzyl or butyl l-thio-beta-D-xylopyranosides and 4-naphthyl, 2-naphthyl and phenyl beta-D-xylopyranosides.

A multinational investigation of the impact of subcutaneous sumatriptan. I: Design, methods and clinical findings

This report describes the design, methods and clinical results of a prospective sequential multinational (5 countries) study conducted to evaluate the effects of subcutaneous sumatriptan on health-related quality of life, workplace productivity, clinical parameters and patient satisfaction. Adult patients with moderate to severe migraine initially received customary therapy for migraine episodes for 12 weeks, followed by 24 weeks' treatment with self-administered subcutaneous sumatriptan 6 mg. Demographic, baseline, health-related quality of life and patient satisfaction rating data were collected during visits to the clinic. Data relating to migraine symptoms, migraine therapy, work productivity and non-work activity time were collected on diary cards filled out by the patients. 749 patients were recruited to the study and 637 received at least 1 dose of sumatriptan. Overall, 75.5% of migraines were successfully treated within 2 hours with sumatriptan compared with 31.9% with customary therapy; 36% of patients reported complete relief at 2 hours with sumatriptan treatment compared with 1% of patients receiving customary therapy. 69% of patients successfully treated 70% of their migraines with sumatriptan within 2 hours, compared with 12% of patients with customary therapy. No serious adverse events were reported; 50% of patients reported an adverse event during the 12-week customary therapy phase and 89% of patients during the 24-week sumatriptan phase. These clinical results, which are consistent with those reported in randomised blinded studies of subcutaneous sumatriptan, suggest that relief of migraine symptoms occurs more often, and in less time, in patients receiving subcutaneous sumatriptan rather than customary therapy as their primary medication.

A multinational investigation of the impact of subcutaneous sumatriptan. III: Workplace productivity and non-workplace activity

This report presents the workplace productivity and non-workplace activity results of a multinational study of the effects of subcutaneous sumatriptan 6 mg in the acute treatment of migraine compared with patient's customary therapy. Patients diagnosed with migraine treated their symptoms for 24 weeks with subcutaneous sumatriptan after a 12-week period of treating symptoms with their customary (non-sumatriptan) therapy. Patients used diary cards to record information concerning the effects of migraine on workplace productivity and non-workplace activity time. The average workplace productivity time lost was 23.4 hours per patient during 12 weeks of customary therapy, compared with 7.2 and 5.8 hours per patient during the first and second 12-week periods of sumatriptan therapy, respectively. An average of 9.3 hours of non-workplace activity time was lost per patient during the customary therapy phase, compared with 3.2 and 2.8 hours during the first and second 12-week periods of sumatriptan therapy, respectively. Treatment of migraine with subcutaneous sumatriptan compared with customary therapy was associated with an average gain per patient of approximately 16 hours of workplace productivity time and 6 hours of non-workplace activity time, over a 3-month period.

A multinational investigation of the impact of subcutaneous sumatriptan. II: Health-related quality of life

The aim of this prospective sequential multinational (5 countries) study was to concurrently evaluate the effects of subcutaneous sumatriptan on clinical parameters, health-related quality-of-life (HRQOL) measures, workplace productivity and patient satisfaction. This report presents the HRQOL results. 582 patients (aged 18 to 65 years) with moderate to severe migraine received their customary antimigraine therapy for 12 weeks and then subcutaneous sumatriptan for 24 weeks. The Short Form-36 Health Survey and the Migraine-Specific Quality of Life Questionnaire were completed at a screening visit (base-line), at the end of the 12-week customary therapy phase, and at 12 and 24 weeks of the sumatriptan phase. Scores for most of the Short Form-36 dimensions improved significantly (p < 0.05) after 12 and 24 weeks of sumatriptan therapy compared with 12 weeks of customary therapy, in each country. Similarly, scores on all Migraine-Specific Quality of Life Questionnaire dimensions were significantly (p < 0.05; paired t-test) improved after 12 weeks (in all countries) and 24 weeks (in 4 of 5 countries) of sumatriptan therapy compared with 12 weeks of customary therapy. This study demonstrates that, in 5 countries, treatment of migraine attacks with subcutaneous sumatriptan compared with customary therapy was associated with improvements in HRQOL, as measured by both general health status and disease-specific instruments.

Sensitivity-enhanced echo-planar MRI at 1.5T using a 5 x 5 mesh dome resonator

In this work a 5 x 5 mesh dome resonator that has been optimized for functional brain imaging is presented. The resonator was reduced in length and diameter compared with previous versions to reduce sample losses, thus enhancing the signal-to-noise ratio of the acquired data. In addition, a 5 x 5 mesh design was employed, which offered improved axial homogeneity over an earlier 3 x 3 mesh version. The new resonator exhibited high sensitivity and good homogeneity over the brain volume, permitting analysis of functional activation over large areas of the cerebral cortex. In a direct comparison with a standard clinical head-imaging resonator, the high sensitivity of the 5 x 5 mesh dome resonator resulted in greater statistical confidence in functional activation.

Effects of gender, body composition, and menopause on plasma concentrations of leptin

Circulating concentrations of leptin ([leptin]) vary directly with body mass index and percentage body fat, and may thus constitute an afferent limb of a system regulating body fatness. We tested the hypotheses that: 1) Plasma [leptin] vary more directly with absolute fat mass than with fractional body fatness per se: and 2). The relationship between fat mass and [leptin] is significantly affected by gender and by menopausal status. [Leptin] in the post-absorptive state was examined in 67 subjects (26 male, 20 premenopausal female, 21 postmenopausal females; 43 never-obese, 24 obese) at usual body weight. Body composition was determined by hydrodensitometry, and [leptin] was determined by a double antibody ELISA assay. In male and pre-menopausal female subjects, subcutaneous adipose tissue aspirations were performed for determination of adipocyte volume by the osmium fixation method, and a 3 hour oral glucose tolerance tests was performed. At usual body weight, ([leptin]) was better correlated with absolute fat mass than with body mass index (BMI) or percentage body fat. BMI and % body fat did not account for any of the variance in [leptin] beyond that attributable to FM, per se. The regression equations relating FM to [leptin] did not differ significantly between obese and never-obese subjects. [Leptin] and fasting serum insulin concentrations were significantly correlated in males only. [Leptin] was significantly higher in pre- and post-menopausal females compared to males, even when [leptin] was corrected for differences in body composition (pre-menopausal females > post-menopausal females > males). While plasma [leptin], corrected for FM, declines significantly in women post-menopause, this decline is not sufficient to account for the striking sexual dimorphism in the relationship of leptin to fat mass. This sexual dimorphism is apparently also due, in part, to a suppressive effect of circulating androgens on [leptin].

A gene correlate of geotaxis near Adh (2-50.1) in Drosophila melanogaster

As part of a long-term study (38+ years) to identify genetic correlates of geotaxis in Drosophila melanogaster, the investigators report the results of allozyme-level analyses of 2 lines derived from hybridizing high- and low-selected lines that have evolved stable, extreme expressions of geotaxis. Allelic variation at Adh was associated with geotactic performance in 1 hybrid-derived line, but not in another, after 66 free-mating generations beyond the F2 generation. A second-chromosome gene correlate of geotaxis may lie within 1 map unit of Adh. Population genetic analyses suggest that there were different selection pressures on the hybrid-derived lines and that the fixation of PGD-A in the high-geotaxis line was probably due to a founder-effect event.

Redox sites of NMDA receptors can modulate epileptiform activity in hippocampal slices from kainic acid-treated rats

Using an animal model of temporal lobe epilepsy, the kainic acid lesioned rat hippocampus, we have evaluated the possibility of modulating glutamate N-methyl-D-aspartate (NMDA) receptor-dependent evoked epileptiform activity through the manipulation of NMDA receptor redox sites. Epileptiform activity was recorded extracellularly from hippocampal slices, in the stratum pyramidale of the CA1 area, and the effects of the oxidizing reagent 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and the reducing agent Tris(2-carboxy ethyl)phosphine (TCEP) on these responses were quantified. Epileptiform activity was substantially reduced in the presence of DTNB but was fully reinstated with the application of TCEP. The effects of both drugs persisted even after wash. Epileptiform activity was totally abolished in the presence of the NMDA receptor antagonist D-2-amino-5-phosphonovaleric acid. These results suggest that epileptiform activity can be controlled by manipulation of the redox sites of NMDA receptors and raise the possibility of developing new anticonvulsant drugs which do not fully block NMDA receptor-mediated synaptic transmission.

Human fatty acid synthesis is stimulated by a eucaloric low fat, high carbohydrate diet

A new experimental approach was used to determine whether a eucaloric, low fat, high carbohydrate diet increases fatty acid synthesis. Normally volunteers consumed low fat liquid formula diets (10% of calories as fat and 75% as glucose polymers, n = 7) or high fat diets (40% of calories as fat and 45% as glucose polymers, n = 3) for 25 d. The fatty acid composition of each diet was matched to the composition of each subject's adipose tissue and compared with the composition of VLDL triglyceride. By day 10, VLDL triglyceride was markedly enriched in palmitate and deficient in linoleate in all subjects on the low fat diet. Newly synthesized fatty acids accounted for 44 +/- 10% of the VLDL triglyceride. Mass isotopomer distribution analysis of palmitate labeled with intravenously infused 13C-acetate confirmed that increased palmitate synthesis was the likely cause for the accumulation of triglyceride palmitate and "dilution" of linoleate. In contrast, there was minimal fatty acid synthesis on the high diet. Thus, the dietary substitution of carbohydrate for fat stimulated fatty acid synthesis and the plasma accumulation of palmitate-enriched, linoleate-deficient triglyceride. Such changes could have adverse effects on the cardiovascular system.

Cytogenetic findings in 175 patients indicate that items of the Kiel classification should not be disregarded in the REAL classification of lymphoid neoplasms

Cytogenetics have proved to be a valuable tool for classifying systemic lymphatic neoplasms, as this technique allows different stem line aberrations and clonal developments to be distinguished. This study was designed to analyze how far groups defined according to common cytogenetic features correlated with their position in either the Kiel (KC) or the REAL classification. Cytogenetic analyses were performed on material from 175 patients with lymphoid neoplasms (LN). Samples were prepared from peripheral blood and bone marrow in acute lymphoblastic leukemia (ALL), from bone marrow in multiple myeloma (MM), and from lymph node biopsies in lymphomas. The results of this study support the inclusion of ALL, MM, and extranodal lymphomas into a comprehensive classification, because their chromosomal aberrations were always characteristic for LN. From the cytogenetic point of view, a subgroup of ALL appears as a leukemic manifestation of lymphoblastic lymphoma. MM have structural aberrations of chromosomes 1, 11, and 14 and secondary aberrations of chromosomes 3, 6, 7, 12, 13, and 18, all of which are characteristic for lymphatic disease. The groups with follicle center cell lymphoma and mantle cell lymphoma correlate well with our results both in the low-grade subtype and in the blastic variant type, the majority of cases demonstrating t(14; 18) and its variants and t(11; 14), respectively. In contrast, the group of diffuse large B-cell (DLB) lymphomas proved to be heterogeneous on the basis of our cytogenetic results. Accordingly, we would suggest keeping the immunoblastic lymphoma (IB) subtype defined by the KC. IB demonstrates no stem line aberration in common with any other group and seems to be characterized by stem line aberrations involving chromosomes 3 and 6. As some DLB lymphomas have a t(14;18) or variant translocations involving chromosome 18, they should either be separated as a subgroup or included into the group of follicle center lymphomas.

A comparative study of different means of assessing long-term energy expenditure in humans

We compared three independent techniques for measurement of total energy expenditure (TEE) in human subjects: 1) weight-maintaining energy intake (dietTEE), 2) 24-h chamber calorimetry (chamberTEE), and 3) differential elimination rates 2H2O and H(2)18O (isotopeTEE). Twenty-three healthy adult in-patients [19 never obese (NO), 2 obese (OB), and 2 formerly-obese (RO); 9 female, 14 malel] ingested a liquid formula diet (40% of calories as fat, 45% carbohydrate, 15% protein), the volume of which was adjusted until body weight was stable for at least 14 days. Body composition was then determined by hydrodensitometry, isotope dilution, and dual photon beam absorptiometry (DXA). The thermic effect of feeding (TEF) and resting energy expenditure [REE; measured before arising (dietREE) and after arising (chamberREE)] were determined by indirect calorimetry. Non-resting energy expenditure (NREE) was calculated as NREE = TEE - (REE + TEF). Subjects then gained or lost 10% of their body weight and were restudied as described above. All measures of TEE were significantly correlated (dietTEE vs. chamberTEE r2 = 0.75; dietTEE vs. isotopeTEE r2 = 0.88; isotopeTEE vs. chamberTEE r2 = 0.73; P < 0.0001). ChamberTEE (mean +/- SE = 2,107 +/- 64 kcal/day) was approximately 20% lower than either dietTEE (2,536 +/- 94 kcal/day, P < 0.0001) or isotopeTEE (2,564 +/- 83 kcal/day, P < 0.0001). When data were normalized to metabolic mass, weight gain of 10% was associated with significant increases in dietTEE (P < 0.005) and isotopeTEE (P < 0.05) but not chamberTEE; weight loss of 10% was associated with significant reductions in dietTEE (P < 0.005) and isotopeTEE (P < 0.05) but not chamberTEE. We conclude that measures of energy expenditure obtained in a highly controlled environment by caloric titration (dietTEE) or differential excretion rates of 2H2O and H(2)18O (isotopeTEE) are not significantly different and that measurements of TEE obtained in a respiratory chamber (chamberTEE) are significantly lower than dietTEE or isotopeTEE, probably largely due to limitations on physical activity in the chamber.

Activated partial thromboplastin time and outcome after thrombolytic therapy for acute myocardial infarction: results from the GUSTO-I trial

BACKGROUND

Although intravenous heparin is commonly used after thrombolytic therapy, few reports have addressed the relationship between the degree of anticoagulation and clinical outcomes. We examined the activated partial thromboplastin time (aPTT) in 29,656 patients in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) trial and analyzed the relationship between the aPTT and both baseline patient characteristics and clinical outcomes.

METHODS AND RESULTS

Intravenous heparin was administered as a 5000-U bolus followed by an initial infusion of 1000 U/h, with dose adjustment to achieve a target aPTT of 60 to 85 seconds. aPTTs were collected 6, 12, and 24 hours after thrombolytic administration. Higher aPTT at 24 hours was strongly related to lower patient weight (P < .00001) as well as older age, female sex, and lack of cigarette smoking (all PT< .0001). At 12 hours, the aPTT associated with the lowest 30-day mortality, stroke, and bleeding rates was 50 to 70 seconds. There was an unexpected direct relationship between the aPTT and the risk of subsequent reinfarction. There was a clustering of reinfarction in the first 10 hours after discontinuation of intravenous heparin.

CONCLUSIONS

Although the relationship between aPTT and clinical outcome was confounded to some degree by the influence of baseline prognostic characteristics, aPTTs higher than 70 seconds were found to be associated with higher likelihood of mortality, stroke, bleeding, and reinfarction. These findings suggest that until proven otherwise, we should consider the aPTT range of 50 to 70 seconds as optimal with intravenous heparin after thrombolytic therapy.