An integrated methodology to assess the benefits of urban green space

The interrelated issues of urban sprawl, traffic congestion, noise, and air pollution are major socioeconomic problems faced by most European cities. A methodology is currently being developed for evaluating the role of green space and urban form in alleviating the adverse effects of urbanisation, mainly focusing on the environment but also accounting for socioeconomic aspects. The objectives and structure of the methodology are briefly outlined and illustrated with preliminary results obtained from case studies performed on several European cities.

Rituximab consolidation after high-dose chemotherapy and autologous blood stem cell transplantation in follicular and mantle cell lymphoma: a prospective, multicenter phase II study

BACKGROUND

Patients with follicular (FL) or mantle cell lymphoma (MCL) are incurable with conventional therapy. We investigated the safety and efficacy of rituximab consolidation after autologous stem cell transplantation (ASCT) in order to prevent relapse by clearance of minimal residual disease (MRD).

METHODS

Rituximab was given approximately 8 weeks after CD34+ cell enriched ASCT at 375 mg/m2, weekly for 4 weeks. Monitoring of MRD was performed by repetitive PCR analyses.

RESULTS

Thirty-one patients were included; one died early after ASCT before rituximab administration. Thirty patients (20 FL, 10 MCL) were evaluable after rituximab consolidation, and 27 of these were assessable for MRD detection. Rituximab consolidation post-ASCT was safe, the most common toxicity being infection. At a median follow-up of 42 months (range 13-96) after ASCT, 25 patients were censored with an actuarial event-free survival (EFS) of 81% at 4 and 5 years. Four patients (two FL, two MCL) relapsed, and one additional MCL patient died unexpectedly in complete remission. PCR-negativity was observed in 22% of the patients before ASCT, 53% post-ASCT (P=0.0547), 72% after rituximab (P=0.0018) and 100% at 6 months post-transplant (P < 0.001).

CONCLUSIONS

One single course of rituximab consolidation given after ASCT is safe, may help to eliminate MRD and may translate into improved EFS in both FL and MCL patients.

[Morphine inhibits complement receptor expression, phagocytosis and oxidative burst by a nitric oxide dependent mechanism]

OBJECTIVE

Monocytes play a crucial role in the immune response by recognition, ingestion, and intracellular killing of microorganisms. We investigated whether morphine and fentanyl influence CD 11b and CD35 surface receptor expression, phagocytic activity and superoxide anion generation of monocytes in a whole blood flow cytometric assay.

METHODS

Whole blood of 13 healthy volunteers was incubated with different morphine and fentanyl concentrations. Expression of surface receptors CD 11b and CD35 was determined by fluorochrome-labelled antibodies. Phagocytic activity was assessed by ingestion of fluorescent bacteria. Conversion of dihydrorhodamin served for oxidative burst measurements.

RESULTS

Morphine inhibited monocyte function in a concentration and time dependent manner. Morphine-induced changes were abolished by preincubation with the NO synthase inhibitor N-nitro-l-arginine as well as naloxone. Fentanyl failed to inhibit receptor expression, phagocytosis and reactive oxygen production by monocytes in clinically relevant as well as supraclinical concentrations.

CONCLUSION

Our results suggest that these monocyte functions are inhibited by a morphine-stimulated NO release mediated by a mu opiate receptor subtype expressed on the surface of monocytes. In contrast, fentanyl did not share morphine's inhibitory effects on monocyte activity.

Effects of endogenous and synthetic opioid peptides on neutrophil function in vitro

BACKGROUND

Opioid peptides released from immunocytes during inflammation and stress in critically ill patients are associated with an altered immune response. Moreover, concentrations of opioid peptides are increased in peripheral blood and at the sites of inflammatory reactions.

METHODS

Using flow cytometric assay of whole human blood, we investigated direct effects of endogenous and synthetic opioid peptides on surface expression of complement receptors CD35 and CD11b/CD18 and Fcã receptor III CD16, and superoxide anion generation of neutrophils.

RESULTS

The endogenous opioid peptides beta-endorphin(1-31) and met-enkephalin, representing the N-terminal fragment of beta-endorphin(1-31), and the synthetic delta opioid receptor agonists D-Ala(2)-D-Leu(5)-enkephalin and D-Pen(2)-enkephalin produced concentration-dependent stimulation of neutrophil activity. Incubation with met-enkephalin 10(-7) M or beta-endorphin(1-31) 10(-7) M led to an increase in receptor expression of up to 10% (met-enkephalin) and 15% (beta-endorphin(1-31)). After incubation with D-Ala(2)-D-Leu(5)-enkephalin or D-Pen(2/5)-enkephalin, receptor expression was increased by up to 30%. This correlated with concentration-dependent stimulation of the production of reactive oxygen intermediates, as shown by an increase of up to 40% in oxidative burst activity. All effects were abolished after preincubation with naloxone or with the selective delta opioid antagonist naltrindole, whereas the selective micro receptor antagonist d-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) showed only partial inhibitory effects.

CONCLUSIONS

Our data suggest a delta opioid receptor-mediated stimulatory effect on neutrophil function. beta-Endorphin(27-31), the C-terminal fragment of beta-endorphin(1-31), did not alter neutrophil function, indicating that beta-endorphin(1-31) mediates its effect on neutrophils via the N-terminal fragment. This study may contribute to a better understanding of neuroimmune interaction.

Temperature course and distribution during plasma heating with a microwave device

In spite of the much shorter thawing times, the use of microwave devices for heating units of fresh frozen plasma is still being discussed. Concerns about general and localised overheating are the main arguments against the use of microwave devices. We evaluated the warming of fresh frozen plasma using the recently introduced Transfusio-therm 2000(R) microwave blood warmer. Units of fresh frozen plasma were weighed and the heating times were recorded. The surface temperature of the fresh frozen plasma bags during heating was recorded every 10 s. Temperature variation on the surface was examined by measuring the difference between peripheral and centrally placed temperature sensors. After heating, plasma temperature was determined using a calibrated thermometer. There were no signs of overheating during the heating process. The surface temperature of three units of fresh frozen plasma heated simultaneously (n = 45) was 34.0 degrees C (SD, 1.5 degrees C) after a mean heating time of 23.2 min (SD, 1.1 min). The mean (SD) temperature difference was -0.6 (0.5) degrees C and the mean (SD) plasma temperature was 33.6 (0.8) degrees C. Heating one fresh frozen plasma unit at a time (n = 20), the mean (SD) heating time was 6.3 (0.4) min. The surface temperature after heating was 34.3 (0.2) degrees C, the mean (SD) temperature difference was -0.6 (0.4) degrees C and the mean (SD) plasma temperature after heating 33.1 (0.6) degrees C. We conclude that no general or localised overheating of fresh frozen plasma occurs during or after heating with the microwave blood warmer.

Early development of neuronal activity in the primate hippocampus in utero

Morphological studies suggest that the primate hippocampus develops extensively before birth, but little is known about its functional development. Patch-clamp recordings of hippocampal neurons and reconstruction of biocytin-filled pyramidal cells were performed in slices of macaque cynomolgus fetuses delivered by cesarean section. We found that during the second half of gestation, axons and dendrites of pyramidal cells grow intensively by hundreds of micrometers per day to attain a high level of maturity near term. Synaptic currents appear around midgestation and are correlated with the level of morphological differentiation of pyramidal cells: the first synapses are GABAergic, and their emergence correlates with the growth of apical dendrite into stratum radiatum. A later occurrence of glutamatergic synaptic currents correlates with a further differentiation of the axodendritic tree and the appearance of spines. Relying on the number of dendritic spines, we estimated that hundreds of new glutamatergic synapses are established every day on a pyramidal neuron during the last third of gestation. Most of the synaptic activity is synchronized in spontaneous slow ( approximately 0.1 Hz) network oscillations reminiscent of the giant depolarizing potentials in neonatal rodents. Epileptiform discharges can be evoked by the GABA(A) receptor antagonist bicuculline by the last third of gestation, and postsynaptic GABA(B) receptors contribute to the termination of epileptiform discharges. Comparing the results obtained in primates and rodents, we conclude that the template of early hippocampal network development is conserved across the mammalian evolution but that it is shifted toward fetal life in primate.

Preoxygenation: a comparison of three different breathing systems

An end-tidal expiratory oxygen concentration (FE'O2) greater than 0.90 is considered to be adequate for preoxygenation. This is generally achieved using a face mask, but this can be unsatisfactory in some patients. We compared preoxygenation in 30 healthy volunteers using a face mask, the NasOral system, which is a novel preoxygenation device, and a mouthpiece with a nose-clip. We measured the maximal FE'O2, the FE'O2 after 2 min and the time to reach maximal FE'O2 and recorded the subjective judgement of the volunteers. The maximal FE'O2 with face mask and mouthpiece was significantly greater than with the modified NasOral system (P<0.05 and P<0.01). With the former devices, a FE'O2 of 0.90 was achieved in 73% of the volunteers vs 46% with the modified NasOral system. Using the mouthpiece, the FE'O2 after 2 min was significantly higher than using the face mask (P<0.01) or the modified NasOral system (P<0.01). The time to maximal FE'O2 was significantly shorter using the modified NasOral system than with the face mask or mouthpiece (P<0.001 and P=0.0001). The volunteers gave more positive ratings to the face mask and mouthpiece than to the modified NasOral system (P<0.001 and P<0.01). We conclude that the use of a mouthpiece can improve preoxygenation in some patients. The results obtained with the modified NasOral system do not justify its introduction into clinical practice.

Point-of-care testing apparatus. Measurement of coagulation

Point-of-care testing of coagulation parameters provides a more rapid assessment of test results compared with laboratory testing. A new coagulation monitor (GEM PCL, Instrumentation Laboratory, Kirchheim, Germany) was evaluated. Point-of-care data for activated partial thromboplastin time and prothrombin time (expressed as the international normalised ratio) and turn-around-time were compared. Coagulation parameters were compared in the blood of 57 patients with and without heparin therapy. The point-of-care and laboratory test results showed a bias (SD) of -0.26 (4.55) s for activated partial thromboplastin time and -0.011 (0.150) s for prothrombin time. The average turn-around-time was 3 min for point-of-care testing vs. 52 min for laboratory testing. We conclude that the reliability of point-of-care testing is sufficient for clinical use.

The effects of leptin administration in non-obese human subjects

OBJECTIVE

Body fatness is partly under hypothalamic control with effector limbs that include the endocrine system and the autonomic nervous system (ANS). In previous studies of both obese and never-obese subjects, we have shown that weight increase leads to increased sympathetic and decreased parasympathetic activity, whereas weight decrease leads to decreased sympathetic and increased parasympathetic activity. We now report on the effect of leptin, independent of weight change, on the ANS.

RESEARCH METHODS AND PROCEDURES

Normal weight males (ages 20-40 years) were fed a solid food diet, measured carefully to maintain body weight, for 3 weeks, as inpatients at the Rockefeller University General Clinical Research Center. In a single-blind, 22-day, placebo/drug/placebo design, six subjects received leptin 0.3 mg/kilogram subcutaneously for 6 days. ANS measures of amount of parasympathetic control and sympathetic control of heart period (interbeat interval) were made by sequential pharmacological blockade with intravenous atropine and esmolol. Norepinephrine, dopamine, and epinephrine levels in 24-hour urine collections were also measured as well as resting metabolic rate.

RESULTS

Sufficient food intake maintained constant body weight in all subjects. There was no evidence that leptin administration led to changes in energy metabolism sufficient to require additional food intake or to alter resting metabolic rate. Likewise, leptin administration did not alter autonomic activity. Parasympathetic control and sympathetic control, as well as the urinary catecholamines, were not significantly affected by leptin administration. Glucose and insulin levels were increased by food intake as expected, but leptin had no affect on these levels before or after food intake.

DISCUSSION

ANS responses to changes in energy metabolism found when food intake and body weight are altered were not found in these never-obese subjects given leptin for 6 days. Although exogenous leptin administration has profound effects on food intake and energy metabolism in animals genetically deprived of leptin, we found it to have no demonstrable effect on energy metabolism in never-obese humans. The effects of longer periods of administration to obese individuals and to those who have lost weight demand additional investigation.

Interconnected large-scale systems for three fundamental cognitive tasks revealed by functional MRI

The specific brain areas required to execute each of three fundamental cognitive tasks - object naming, same-different discrimination, and integer computation - are determined by whole-brain functional magnetic resonance imaging (fMRI) using a novel technique optimized for the isolation of neurocognitive systems. This technique (1) conjoins the activity associated with identical or nearly identical tasks performed in multiple sensory modalities (conjunction) and (2) isolates the activity conserved across multiple subjects (conservation). Cortical regions isolated by this technique are, thus, presumed associated with cognitive functions that are both distinguished from primary sensory processes and from individual differences. The object-naming system consisted of four brain areas: left inferior frontal gyrus, Brodmann's areas (BAs) 45 and 44; left superior temporal gyrus, BA 22; and left medial frontal gyrus, BA 6. The same-different discrimination system consisted of three brain areas: right inferior parietal lobule, BA 40; right precentral gyrus, BA 6; and left medial frontal gyrus, BA 6. The integer computation system consisted of five brain areas: right middle frontal gyrus, BA 6; right precentral gyrus, BA 6; left inferior parietal lobule, BA 40; left inferior frontal gyrus, BA 44; and left medial frontal gyrus, BA 6. All three neurocognitive systems shared one common cortical region, the left medial frontal gyrus, the object-naming and integer computation systems shared the left inferior frontal gyrus, and the integer computation and same-different discrimination systems shared the right precentral gyrus. These results are consistent with connectionist models of cognitive processes where specific sets of remote brain areas are assumed to be transiently bound together as functional units to enable these functions, and further suggest a superorganization of neurocognitive systems where single brain areas serve as elements of multiple functional systems.

Acute stroke patterns in patients with internal carotid artery disease: a diffusion-weighted magnetic resonance imaging study

BACKGROUND AND PURPOSE

Diffusion-weighted (DW) MRI is a sensitive method that facilitates early stroke pattern identification. There are limited data about the influence of stenosis grade on the development of particular stroke patterns in internal carotid artery (ICA) disease. We therefore investigated the lesion patterns on DW MRI in acute stroke patients with ICA disease.

METHODS

DW MRI was analyzed in 102 consecutive acute stroke patients with different degrees of ipsilateral ICA disease. Patients were assigned to 1 of 5 observed lesion patterns: (1) territorial ischemia, (2) subcortical ischemia without or (3) with embolus fragmentation, (4) disseminated lesions in distal cortical regions, and (5) multiple lesions in hemodynamic risk zones. In addition, perfusion-weighted (PW) MRI and MR angiography information was included in the assessment.

RESULTS

All patterns were observed in the different stages of ICA disease. Half of the patients with high-grade or subtotal stenosis had lesions in hemodynamic risk zones. Territorial stroke occurred in 47.6% of patients with ICA occlusion. Statistical analysis showed a significant relationship between the degree of stenosis and the observed stroke pattern (P=0.001). In 77.8% of patients exhibiting high-grade ICA stenosis, subtotal stenosis, or occlusion, the perfusion lesion was larger than the diffusion lesion (PW/DW mismatch).

CONCLUSIONS

Although in the individual patient any of the infarct patterns may occur, in statistical terms the incidence of a particular stroke pattern is clearly dependent on the degree of stenosis.

Discrimination between pentose oligosaccharides containing D-xylopyranose or L-arabinofuranose as non-reducing terminal residue using fast atom bombardment mass spectrometry

Collisional-induced dissociation (CID) mass spectra of the [M + H](+) and [M - H](-) ions obtained under fast atom bombardment conditions of a number of methyl glycoside di-, tri- and tetrasaccharides, containing D-xylopyranosyl and/or L-arabinofuranosyl residues at the non-reducing terminus, do not provide information about their ring size. This information could only be obtained from a careful comparison of the intensity ratio of the [M + Na - 90](+) and [M + Na - 104](+) ions ((0,2)X(t)/(1,5)X(t)) in the high-energy CID spectra of the sodium-cationized di-, tri- and probably also tetrasaccharide compounds.

Comparative efficacy of clarithromycin modified-release and clarithromycin immediate-release formulations in the treatment of lower respiratory tract infection

BACKGROUND

A modified-release (MR) formulation of clarithromycin, distinct from the extended-release formulation, has recently been developed and has efficacy and tolerability similar to standard immediate-release (IR) clarithromycin, with the advantage of once-daily dosing.

OBJECTIVE

The purpose of this study was to compare the efficacy (as measured by relief of clinical symptoms and eradication of specific pathogens) and tolerability of clarithromycin MR 500 mg administered once daily versus clarithromycin IR 250 mg administered twice daily for 5 days.

METHODS

In this randomized, double-blind (with matching placebo), parallel-group. multicenter, controlled trial, patients with lower respiratory tract infection were randomized to 1 of 2 treatment regimens: clarithromycin MR 500 mg once daily plus clarithromycin IR 250 mg placebo twice daily or clarithromycin IR 250 mg BID plus clarithromycin MR 500 mg placebo once daily.

RESULTS

Statistically equivalent clinical cure and success rates, overall symptomatic improvement, and bacteriologic responses were achieved with both treatments. In the clarithromycin MR group, the clinical cure rate was 72.5% (87/120), and the clinical success rate (cure plus symptomatic improvement) was 97.5% (117/120). Of the 124 patients treated with clarithromycin IR 250 mg BID, 98 (79.0%) achieved a clinical cure, and 120 (96.8%) achieved clinical success. There were no statistically significant between-group differences in clinical cure or success rates. More than 85% of patients in both study groups experienced improvement in dyspnea, cough, wheezing, chest discomfort, fatigue, and fever, and the visual appearance of sputum: these symptoms resolved completely in the majority of patients. Bacteriologic response (efficacy against specific pathogens), which was assessed as an objective efficacy criterion, was assessable for 40 patients treated with clarithromycin MR and 49 patients treated with clarithromycin IR. Bacteriologic eradication of the pretreatment target pathogen was achieved in 95.0% (38/40) of assessable patients treated with clarithromycin MR 500 mg once daily and 91.8% (45/49) of patients treated with clarithromycin IR 250 mg BID. Treatment-related adverse events were mild to moderate in all cases. Nausea (n = 9), diarrhea (n = 6), abdominal pain (n = 5), and gastric pain (n = 3) were the only study drug-related adverse events reported by > or = 1 patient in each treatment arm. Diarrhea was reported only in the clarithromycin IR group (n = 6) (P = 0.029 vs clarithromycin MR).

CONCLUSIONS

Clarithromycin MR 500 mg administered once daily for 5 days is as effective and well tolerated as the IR formulation, with the advantage of once-daily dosing and fewer episodes of diarrhea.

Hearing loss after spinal and general anesthesia: A comparative study

Hearing loss has been described after spinal anesthesia. We examined the hearing in patients before and after spinal and general anesthesia by pure tone audiometry (LdB: 125-1500 Hz; HdB: 2000-8000 Hz). Tympanic membrane displacement analysis was used to noninvasively monitor the intralabyrinthine and intracranial pressure. Eighteen patients received spinal anesthesia (G(SA)); 19 patients general anesthesia (G(GA)). Pure tone audiometry and TMD data were obtained preoperatively ((0)) and postoperatively on day 1 ((1)) and 2 ((2)). The mean threshold differences (Delta) in LdB(10) and LdB(20) were significantly different in G(SA) compared with G(GA) (DeltaLdB(10) + 0.15+/-3.07 dB vs. -1.34+/-3.77 dB, P = 0.05; DeltaLdB(20) -0.54+/-2.24 dB vs. -2.45+/-3.39 dB, P<0.01). However, there were no differences in DeltaHdB(10) between G(SA) and G(GA), but in DeltaHdB(20) (-1.40+/-3.95 dB vs -5.12+/- 6.35 dB, P = <0.01). We found a significant correlation between the magnitude of intraoperative intravascular volume replacement and low-frequency hearing loss. Tympanic membrane displacement values were not different pre- and postoperatively. Hearing was impaired after spinal and general anesthesia. Low-frequency hearing loss was correlated with intraoperative volume replacement. Tympanic membrane recordings did not reveal significant changes.

A chromogenic substrate for a beta-xylosidase-coupled assay of alpha-glucuronidase

4-Nitrophenyl 2-(4-O-methyl-alpha-d-glucopyranuronosyl)-beta-d-xylopyranoside obtained on deesterification of 4-nitrophenyl 2-O-(methyl 4-O-methyl-alpha-d-glucopyranosyluronate)-beta-d-xylopyranoside (Hirsch et al., Carbohydr. Res. 310, 145-149, 1998) was found to be an excellent substrate for the measurement of hemicellulolytic alpha-glucuronidase activity. A new precise alpha-glucuronidase assay was developed by coupling the alpha-glucuronidase-catalyzed formation of 4-nitrophenyl beta-d-xylopyranoside with its efficient hydrolysis by beta-xylosidase. A recombinant strain of Saccharomyces cerevisiae, harboring and expressing the beta-xylosidase gene xlnD of Aspergillus niger under control of the alcohol dehydrogenase II promoter on a multicopy plasmid, was used as a source of beta-xylosidase. The activity values of beta-xylosidase in the assay required to achieve a steady-state rate of 4-nitrophenol formation shortly after starting the alpha-glucuronidase reaction were obtained both experimentally and by calculation using the kinetics of coupled enzyme reactions.

An integrated functional magnetic resonance imaging procedure for preoperative mapping of cortical areas associated with tactile, motor, language, and visual functions

OBJECTIVE

To evaluate an integrated battery of preoperative functional magnetic resonance imaging (fMRI) tasks developed to identify cortical areas associated with tactile, motor, language, and visual functions.

METHODS

Sensitivity of each task was determined by the probability that a targeted region was activated for both healthy volunteers (n = 63) and surgical patients with lesions in these critical areas (n = 125). Accuracy of each task was determined by the correspondence between the fMRI maps and intraoperative electrophysiological measurements, including somatosensory evoked potentials (n = 16), direct cortical stimulation (n = 9), and language mapping (n = 5), and by preoperative Wada tests (n = 13) and visual field examinations (n = 6).

RESULTS

For healthy volunteers, the overall sensitivity was 100% for identification of the central sulcus, visual cortex, and putative Wernicke's area, and 93% for the putative Broca's area (dominant hemisphere). For patients with tumors affecting these regions of interest, task sensitivity was 97% for identification of the central sulcus, 100% for the visual cortex, 91% for the putative Wernicke's area, and 77% for the putative Broca's area. These sensitivities were enhanced by the use of multiple tasks to target related functions. Concordance of the fMRI maps and intraoperative electrophysiological measurements was observed whenever both techniques yielded maps and Wada and visual field examinations were consistent with fMRI results.

CONCLUSION

This integrated fMRI task battery offers standardized and noninvasive preoperative maps of multiple critical functions to facilitate assessment of surgical risk, planning of surgical routes, and direction of conventional, intraoperative electrophysiological procedures. Thus, a greater range of structural and functional relationships is brought to bear in the service of optimal outcomes for neurosurgery.

Concordance between functional magnetic resonance imaging and intraoperative language mapping

Although the correspondence between functional-magnetic resonance imaging (fMRI) representations of the sensorimotor cortex and intraoperative electrophysiology (including somatosensory evoked potential, SSEP, recordings and direct cortical stimulation) has been reported, a similar correspondence between fMRI and intraoperative localization of the language-sensitive cortex is not as well established. The aim of the present study was to evaluate the concordance between fMRI and intraoperative electrophysiology with respect to the localization of the language-sensitive and sensorimotor cortices. We present the results of 21 patients who underwent language and sensorimotor mapping by fMRI and intraoperative electrophysiology including SSEP recordings (n = 21), direct cortical stimulation of motor cortex (n = 15) and direct cortical stimulation of Broca's and Wernicke's area (n = 5). When responses were obtained with both methods, localization of function concurred in all cases. These observations suggest that fMRI represents a reliable preoperative tool for the identification of language-sensitive areas.

Effects of changes in body weight on carbohydrate metabolism, catecholamine excretion, and thyroid function

BACKGROUND

Weight gain and loss increases and decreases energy expenditure, respectively, out of proportion to changes in metabolic mass.

OBJECTIVE

We hypothesized that changes in energy expenditure associated with weight gain or loss were due in part to changes in catecholamine release, thyroid hormones, carbohydrate utilization, or a combination thereof.

METHODS

Urinary catecholamine excretion, serum thyroid hormone concentrations, and results of 3-h oral-glucose-tolerance tests were examined in obese and never-obese subjects at their usual weights, during weight loss or gain, and at stable weights 10-20% below or 10% above usual.

RESULTS

Urinary norepinephrine excretion decreased significantly during and after weight loss and increased during and after weight gain. Serum concentrations of reverse triiodothyronine increased significantly during and after weight loss, whereas serum concentrations of triiodothyronine increased significantly (by approximately 0%) during and after weight gain. Serum insulin and glucose concentrations during the oral-glucose-tolerance test increased significantly after weight gain in obese subjects. The percentage change in urinary norepinephrine excretion and in serum concentrations of triiodothyronine were significantly correlated with percentage changes in energy expenditure and with each other.

CONCLUSIONS

Changes in body weight were associated with changes in catecholamine excretion and thyroid hormones, which might-by virtue of the effects on energy expenditure-have favored a return to usual body weight. Weight gain induced more apparent insulin resistance in the obese than the never-obese subjects, suggesting a threshold effect of total body fat on this phenomenon.

Glomerular hemodynamics in severe obesity

Differential solute clearances were used to characterize glomerular function in 12 nondiabetic subjects with severe obesity (body mass index >38). Nine healthy subjects served as the control group. In the obese group, glomerular filtration rate (GFR) and renal plasma flow (RPF) exceeded the control value by 51 and 31%, respectively. Consequently, filtration fraction increased. The augmented RPF suggested a state of renal vasodilatation involving, mainly or solely, the afferent arteriole. Albumin excretion rate and fractional albumin clearance increased by 89 and 78%, respectively. Oral glucose tolerance tests were suggestive of insulin resistance. Insulin resistance was positively correlated with GFR (r = 0.88, P<0.001) and RPF (r = 0.72, P <0.001). Mean arterial pressure was higher than in the control group. Fractional clearances of dextrans of broad size distribution tended to be lowered. The determinants of the GFR were estimated qualitatively by using a theoretical model of dextran transport through a heteroporous membrane. This analysis suggests that the high GFR in very obese subjects may be the result of an increase in transcapillary hydraulic pressure difference (DeltaP). An abnormal transmission of increased arterial pressure to the glomerular capillaries through a dilated afferent arteriole could account for the augmentation in DeltaP.

The effects of drugs used to treat obesity on the autonomic nervous system

OBJECTIVE

Body fatness is partly under hypothalamic control with effector limbs, which include the endocrine system and the autonomic nervous system (ANS). In previous studies we have shown, in both obese and never-obese subjects, that weight increase leads to increased sympathetic and decreased parasympathetic activity, whereas weight decrease leads to decreased sympathetic and increased parasympathetic activity. We now report on the involvement of such ANS mechanisms in the action of anti-obesity drugs, independent of change in weight.

RESEARCH METHODS AND PROCEDURES

Normal weight males (ages 22 to 38 years) were fed a solid food diet, carefully measured to maintain body weight, for at least 2 weeks, as inpatients at the Rockefeller University General Clinical Research Center. In a single-blind, placebo/drug/placebo design, eight subjects received dexfenfluramine, seven phentermine (PHE), and seven sibutramine (SIB). ANS measures of parasympathetic and sympathetic activity included: determination of amount of parasympathetic control (PC) and sympathetic control (SC) of heart period (interbeat interval), using sequential pharmacological blockade by intravenous administration of atropine and esmolol. These autonomic controls of heart period are used to estimate the overall level of parasympathetic and sympathetic activities. Norepinephrine, dopamine, and epinephrine levels in 24-hour urine collections were measured and also resting metabolic rate (RMR).

RESULTS

Sufficient food intake maintained constant body weight in all groups. PHE and SIB produced significant increases in SC but no change in PC or in RMR. In contrast, dexfenfluramine produced marked decreases in SC, PC, and RMR. For all three drugs, the effects on urine catecholamines directly paralleled changes in cardiac measures of SC.

DISCUSSION

ANS responses to PHE and SIB were anticipated. The large, and unanticipated, response to dexfenfluramine suggests further study to determine whether there could be any relation of these ANS changes to the adverse cardiovascular effects of treatment with dexfenfluramine.

Relation of cortical language distribution and cognitive function in surgical epilepsy patients

PURPOSE

To investigate the relation between the number and spatial distribution of language sites and specific patient-and epilepsy-related variables.

METHODS

Patients with stimulation-induced reading or naming errors from anterior or inferior temporal cortex (i.e., atypical temporal language sites) were compared with those with language sites confined to Wernicke's area (WA) in the posterosuperior temporal and inferior parietal perisylvian area. In a consecutive series of 44 left hemisphere language dominant patients with complex partial seizures before left temporal lobectomy, correlations were compared between cortical language distribution and measures of cognitive function.

RESULTS

Patients with atypical temporal language sites (group 1) had significantly fewer years of education that did patients with language sites in WA (group 2). Patients in group 1 had poorer verbal learning and fluency than did patients in group 2. Patients with IQ <80 were significantly more likely to have multiple sites where stimulation disrupted language than did patients with normal IQ. Number of language sites had significant negative correlations with full-scale IQ, and measures of confrontation naming, verbal fluency, and immediate verbal memory.

CONCLUSIONS

Language cortex has a wider spatial distribution in epilepsy surgery patients with lower intelligence, poorer education, and worse verbal and memory skills.

Relationship between carbohydrate-induced hypertriglyceridemia and fatty acid synthesis in lean and obese subjects

We previously reported that a eucaloric, low fat, liquid formula diet enriched in simple carbohydrate markedly increased the synthesis of fatty acids in lean volunteers. To examine the diet sensitivity of obese subjects, 7 obese and 12 lean volunteers were given two eucaloric low fat solid food diets enriched in simple sugars for 2 weeks each in a random-order, cross-over design (10% fat, 75% carbohydrate vs. 30% fat, 55% carbohydrate, ratio of sugar to starch 60:40). The fatty acid compositions of both diets were matched to the composition of each subject's adipose tissue and fatty acid synthesis measured by the method of linoleate dilution in plasma VLDL triglyceride. In all subjects, the maximum % de novo synthesized fatty acids in VLDL triglyceride 3;-9 h after the last meal was higher on the 10% versus the 30% fat diet. There was no significant difference between the dietary effects on lean (43+/-13 vs. 12+/-13%) and obese (37+/-15 vs. 6+/-6%) subjects, despite 2-fold elevated levels of insulin and reduced glucagon levels in the obese. Similar results were obtained for de novo palmitate synthesis in VLDL triglyceride measured by mass isotopomer distribution analysis after infusion of [(13)C]acetate. On the 10% fat diet, plasma triglycerides (fasting and 24 h) were increased and correlated with fatty acid synthesis. Triglycerides were higher when fatty acid synthesis was constantly elevated rather than having diurnal variation.Thus, eucaloric, solid food diets which are very low in fat and high in simple sugars markedly stimulate fatty acid synthesis from carbohydrate, and plasma triglycerides increase in proportion to the amount of fatty acid synthesis. However, this dietary effect is not related to body mass index, insulin, or glucagon levels.

Visual function and brain organization in non-decussating retinal-fugal fibre syndrome

Functional neuroimaging, psychophysical and electrophysiological investigations were performed in a patient with non-decussating retinal-fugal fibre syndrome, an inborn achiasmatic state in which the retinal projections of each eye map entirely to the ipsilateral primary visual cortex. Functional magnetic resonance imaging (fMRI) studies showed that for monocularly presented simple visual stimuli, only the ipsilateral striate cortex was activated. Within each hemisphere's striate cortex, the representation of the two hemifields overlapped extensively. Despite this gross miswiring, visual functions that require precise geometrical information (such as vernier acuity) were normal, and there was no evidence for the confounding of visual information between the overlapping ipsi-lateral and contralateral representations. Contrast sensitivity and velocity judgments were abnormal, but their dependence on the orientation and velocity of the targets suggests that this deficit was due to ocular instabilities, rather than the miswiring per se. There were no asymmetries in performance observed in visual search, visual naming or illusory contour perception. fMRI analysis of the latter two tasks under monocular viewing conditions indicated extensive bilateral activation of striate and prestriate areas. Thus, the remarkably normal visual behavior achieved by this patient is a result of both the plasticity of visual pathways, and efficient transfer of information between the hemispheres.

Bronchiolitis obliterans syndrome after (heart-)lung transplantation. Impaired antiprotease defense and increased oxidant activity

Increased numbers of neutrophils are a common finding in bronchoalveolar lavage fluid (BALF) samples obtained from patients after (heart-)lung transplantation [(H)LTX]. Since proteases and reactive oxygen species secreted by neutrophils are capable of causing substantial damage to the lung tissue if not counterbalanced by the antiprotease and antioxidant screen, we hypothesized that neutrophil products may play a role in the development of obliterative bronchiolitis (OB). A total of 72 BALF samples obtained from 33 patients after (H)LTX were evaluated. Sixteen of these patients were suffering from bronchiolitis obliterans syndrome (BOS) at the time of bronchoalveolar lavage (BAL). As a control, BALF samples from 17 healthy volunteers were analyzed. Anti-neutrophil elastase (NE) activity was quantified by a titration assay. Concentrations of alpha(1)-protease inhibitor (API), secretory leukocyte protease inhibitor (SLPI), NE-API complex, and myeloperoxidase (MPO) were measured by ELISA. Oxidized methionine [Met(O)] was quantified by high-performance liquid chromatography (HPLC). Epithelial lining fluid (ELF) from patients suffering from BOS showed significantly increased neutrophil counts, significantly elevated concentrations of NE-API complex and Met(O), and a significant decrease in the concentration of SLPI. Furthermore, a trend toward an increased NE activity and MPO concentration was observed. These findings suggest that neutrophils may be involved in the development of BOS.

Implants and sinus-inlay bone grafts in a 1-stage procedure on severely atrophied maxillae: surgical aspects of a 3-year follow-up study

This 3-year follow-up study compares implant treatment in 39 1-stage sinus-inlay block-grafted patients (study group) with 37 patients treated without bone grafting (reference group), all of whom were edentulous in the maxilla and were treated over the same time period. The cumulative success rate (CSR) of implant stability after 3 years in the study group was 75.3% in grafted areas and 82.2% in non-grafted areas. The CSR after 3 years in the reference group was 93.1%. The mean marginal bone resorption after 3 years of loading was 1.4 mm in grafted areas and 1.6 mm in non-grafted areas in the study group and 1.1 mm in the reference group. Complications noted during the postoperative healing periods correlated significantly with implant failures later on (P < .05). Since prosthesis stability (CSR) after 3 years was 94.9% in the study group and 97.3% in the reference group, it can be concluded that 1-stage sinus-inlay block grafts can be regarded as a safe method with a predictable outcome for use on patients with severely atrophied edentulous maxillae, although increased failure rates are to be expected for implants placed in bone-grafted regions.

Lack of evidence of acute ischemic tissue change in transient global amnesia on single-shot echo-planar diffusion-weighted MRI

BACKGROUND AND PURPOSE

There is uncertainty concerning the etiology of transient global amnesia (TGA). Previous CT and MRI studies have indicated that permanent structural abnormality is rare in TGA. Diffusion-weighted (DW) MRI is very sensitive to early ischemic parenchymal changes and has recently demonstrated embolic infarction in the posterior cerebral artery territory in 2 TGA patients. We report the findings of DW MRI in 8 patients in acute stages of TGA.

METHODS

Conventional and echo-planar DW MRI was performed in 2 patients in the active phase and 6 patients in the recovery phase (1 to 8 hours after cessation of anterograde memory dysfunction) of spontaneously occurring TGA.

RESULTS

None of the patients showed signs of hyperintensity on DW images or hypointensity on quantitative apparent diffusion coefficient (ADC) maps to suggest regional decreases of water mobility or acute T2 changes on transverse or coronal slices.

CONCLUSIONS

We were unable to detect ADC or acute T2 changes with echo-planar DW MRI in patients with TGA, which suggests that mechanisms other than ischemic infarction may cause TGA. We did not identify spreading depression-associated changes of the ADC. Further refinement of MRI sequences may be necessary to detect subtle or transient signal change in brain parenchyma.

[Echo-planar diffusion-weighted MRI in the diagnosis of acute ischemic stroke: characterisation of tissue abnormalities and limitations in the interpretation of imaging findings]

INTRODUCTION

An accurate diagnosis is frequently difficult in early stroke. Diffusion-weighted (DW) magnetic resonance imaging (MRI) allows visualization of ischemic parenchyma and quantitative assessment of tissue changes before unequivocal abnormalities appear on T(2)-weighted MRI.

METHODS

We analyzed 105 MRI examinations of patients with acute stroke (<24 h) with regard to patterns of abnormalities in T(2)-weighted and DW MRI. Furthermore we assessed the influence of artifacts related to DW echo-planar single-shot MRI on image interpretation.

RESULTS

Depending on the time of patient assessment there were three partly overlapping T(2)/DW patterns: (1) in the very early phase (</=1.5 h after symptom onset) there was no T(2) abnormality and no definite abnormality of diffusion; (2) no T(2) abnormality and restricted diffusion (1.5-4 h); (3) T(2) hyperintensity and restricted diffusion (>/=3 h). Typical artifacts (susceptibility distortions, N/2 artifact, chemical shift artifact and eddy currents artifact) had to be considered when interpreting images.

CONCLUSIONS

Provided typical artifacts are taken into consideration, echo-planar DW MRI allows a more precise diagnostic assessment in acute stroke.

Differential diagnosis and treatment strategies for biologic complications and failing oral implants: a review of the literature

The aim of this article was to review the literature on differential diagnosis and treatment of biologic complications and failing implants. All types of publications, with the exception of abstracts, published in English up to December 1998, were included. A multi-layered search strategy was used. Controlled clinical trials (CCTs) were searched in the Cochrane Oral Health Group's Specialized Register of Trials. This database contains all CCTs identified in MEDLINE and EMBASE. PubMed was searched using various key words and the "related articles" feature. All identified publications were obtained and none were excluded. Infection, impaired healing, and overload are considered the major etiologic factors for the loss of oral implants. Only a few clinical and animal investigations were found that tested the validity of the proposed therapeutic approaches. The treatment of failing implants is still based mainly on empirical considerations, often derived from periodontal research, from data extrapolated from in vitro findings, or from anecdotal case reports performed on a trial-and-error basis.