Parallel input makes the brain run faster

In serial sensory processing, information flows from the thalamus via primary sensory cortices to higher-order association areas. However, association cortices also receive, albeit weak, direct thalamocortical sensory inputs of unknown function. For example, while information proceeds from primary (SI) to secondary (SII) somatosensory cortex in a serial fashion, both areas are known to receive direct thalamocortical sensory input. The present study examines the potential roles of such parallel input arrangements. The subjects were presented with median nerve somatosensory stimuli with the instruction to respond with the contralateral hand. The locations and time courses of the activated brain areas were first identified with magnetoencephalography (MEG). In a subsequent session, these brain areas were modulated with single-pulse transcranial magnetic stimulation (TMS) at 15-210 ms after the somatosensory stimulus while electroencephalography (EEG) was recorded. TMS pulses at 15-40 ms post-stimulus significantly speeded up reaction times and somatosensory-evoked responses, with largest facilitatory effects when the TMS pulse was given to contralateral SII at about 20 ms. To explain the results, we propose that the early somatosensory-evoked physiological SII activation exerts an SII-->SI influence that facilitates the reciprocal SI-->SII pathway - with TMS to SII we apparently amplified this mechanism. The results suggest that the human brain may utilize parallel inputs to facilitate long-distance cortico-cortical connections, resulting in accelerated processing and speeded reaction times. This arrangement could also allow very early top-down modulation of the bottom-up stream of sensory information.     

HMGB1 as a predictor of organ dysfunction and outcome in patients with severe sepsis

OBJECTIVE: To study the predictive value of high mobility group box-1 protein (HMGB1) and hospital mortality in adult patients with severe sepsis. STUDY DESIGN: Prospective observational cohort study in 24 ICUs in Finland. PATIENTS: Two hundred and forty-seven adult patients with severe sepsis. MEASUREMENTS AND MAIN RESULTS: Blood samples for HMGB1 analyses were drawn from 247 patients at baseline and from 210 patients 72 h later. The mean APACHE II and SAPS II scores were 24 (SD 9) and 44 (SD 17), respectively. The hospital mortality was 26%. The serum HMGB1 concentrations were measured first by semi-quantitative Western immunoblotting (WB) analysis. The median HMGB1 concentration on day 0 was 108% (IQR 98.5-119) and after 72 h 107% (IQR 98.8-120), which differed from healthy controls (97.5%, IQR 91.3-106.5; p=0.028 and 0.019, respectively). The samples were re-analysed by ELISA (in a subgroup of 170 patients) to confirm the results by WB. The median concentration in healthy controls was 0.65 ng/ml (IQR 0.51-1.0). This was lower than in patients with severe sepsis (3.6 ng/ml, IQR 1.9-6.5, p< 0.001). HMGB1 concentrations (WB and ELISA) did not differ between hospital survivors and non-survivors. In ROC analyses for HMGB1 levels (WB) on day 0 and 72 h with respect to hospital mortality, the areas under the curve were 0.51 and 0.56 (95% CI 0.40-0.61 and 0.47-0.65). CONCLUSIONS: Serum HMGB1 concentrations were elevated in patients with severe sepsis, but did not differ between survivors and non-survivors and did not predict hospital mortality.     

Solid-state properties and relationship between anhydrate and monohydrate of baclofen

Baclofen, a widely used antispastic agent, has been found to exist in two crystalline forms, the anhydrate and monohydrate. The aim of this study was (1) to identify and characterize these two solid phases of baclofen, and (2) to examine the processing-induced phase transformations associated with wet granulation of baclofen. Using multiple techniques (powder X-ray diffraction, thermal analysis, vibrational spectroscopy and water vapor sorption analysis), a structural relationship has been established between the anhydrate and monohydrate of baclofen. Thermal and variable-temperature powder X-ray diffraction data indicate that the monohydrate, which presumably belongs to the channel hydrate class, dehydrates at 60 degrees C with the formation of the anhydrate. Furthermore, the anhydrate to monohydrate transformation followed by optical microscopy was found to occur via a solvent-mediated route. During wet massing experiments, the critical moisture value for the hydrate formation under the conditions of the present study was identified using qualitative powder X-ray diffraction and Raman spectroscopy. Finally, the interconversion pathway between the two crystalline forms of baclofen was presented. The knowledge of this pathway provides better understanding and control of the solid state of baclofen during processing and storage.     

Laparoscopic sigmoid and rectal resection using an electrothermal bipolar vessel sealing device

BACKGROUND: Laparoscopic colonic resection has gained popularity as a method to treat colonic diseases. The electrothermal bipolar vessel sealer (EBVS; LigaSure Atlas) is a modern device that allows the secure sealing of vessels with a diameter of up to 7 mm. The aim of the present study was to evaluate the suitability of the device for laparoscopic colonic surgery. METHODS: The immediate outcome of 114 consecutive patients who underwent a sigmoid or rectal resection was prospectively analyzed. The intention was to perform all operations with the EBVS for dissection and ligation of the mesenterial vessels. Details on patient characteristics, peroperative and postoperative complications, and postoperative recovery were recorded prospectively and analyzed. RESULTS: One hundred and fourteen patients were scheduled for elective left-sided colonic or rectal resection. Massive intra-abdominal adhesions in 1 patient required a conversion of the laparoscopic procedure to an open one; In total, 113 laparoscopic operations were thus performed. The mean operative time was 87.7 +/- 2.8 minutes, and the mean time for patients to tolerate solid food was 3.4 +/- 0.1 days and the time to discharge from hospital was 4.6 +/- 0.2 days. There were nine (8.0%) general complications, and additionally, 10.6% of patients suffered from surgical complications. CONCLUSIONS: The electrothermal bipolar vessel sealer is suitable and safe for laparoscopic sigmoid and rectal resections. The use of the device probably reduces the operative time.     

Estimation of spinal bone density using conventional MRI: Comparison between MRI and DXA in 32 subjects

We evaluated the usefulness of MRI T1 and T2 relaxation times in assessing bone mineral status. T1 and T2 relaxation times of L3 were measured in 16 pairs of identical twins (24 men, 8 women), aged 25-69 years. Bone mineral density (BMD), bone mineral content (BMC) and apparent volumetric bone mineral density (BMDvol) of L3 were measured from the same subjects using dual x-ray absorptiometry (DXA).

T2 relaxation time correlated inversely with BMD and BMC (r-0.40 and r-0.47, respectively), whereas a significant positive correlation between T1 relaxation time and BMDvol was found (r 0.36). the measurement of T1 may give some information on bone mineral status in clinical MRI measurements when DXA is not available. It is possible that T1 and T2 reflect not only bone density, but also other factors related to bone structure.     

Increase in cerebral blood flow of right prefrontal cortex in man during orgasm

The functional anatomy of human emotional responses has remained poorly understood, mainly because invasive experiments in humans are unacceptable due to ethical reasons. The new functional imaging techniques such as positron emission tomography and single photon emission computed tomography have made it possible to study the neurophysiology of living humans non-invasively. We studied the regional cerebral blood flow with semi-quantitative ^99mTC-HMPAO single photon emission computed tomography in eight healthy right-handed heterosexual males during orgasm. The results showed decrease of cerebral blood flow during orgasm in all other cortical areas except in right prefrontal cortex, where the cerebral blood flow increased significantly (P < 0.005).     

The effects of interleukin-1 and prostaglandin E2 on accumulation of collagen and steady-state levels of proα1(I) collagen messenger RNA in experimental granulation tissue in rats

The effects of human interleukin 1β (IL-1β) and prostaglandin E ₂ (PGE ₂ ) on experimental granulation tissue in rats and on granulation tissue cells in culture were studied. IL-1β and PGE ₂ were injected into subcutaneously implanted sponges during the first 3 days after implantation. The rate of collagen synthesis in fibroblasts was measured as synthesis of protein-bound ³ H-hydroxyproline. The steady-state levels of proα1(I) and proα1(III) collagen chain mRNAs were estimated by Northern transfer analyses. By 7 days postoperatively IL-1β had decreased the hydroxyproline content of granulation tissue. PGE ₂ decreased nonsignificantly the amounts of hydroxyproline, but the steady-state levels of proα1(I) and proα1(III) collagen chain mRNAs were slightly elevated. In IL-1β-treated fibroblast cultures collagen production decreased by 15% and following PGE ₂ treatment by 34% compared with the controls. The latter effect could be abolished by indomethacin. Indomethacin alone stimulated collagen production by 40%. In vivo IL-1 decreases the formation of normal granulation tissue. This effect may be partly due to stimulation of secretion of PGE ₂ . Received: 13 September 1996     

Methanol and Formic Acid Toxicity: Biochemical Mechanisms

Abstract: Metabolism of methanol, methyl ethers, esters and amides give rise to formic acid. This acid is an inhibitor of the mitochondrial cytochrome oxidase causing histotoxic hypoxia. Formic acid is a weaker inhibitor than cyanide and hydrosulphide anions. The body burden of formate in methanol poisoning is high enough to cause acidosis, and other clinical symptoms. Part of the protons can be attributed to formic acid whereas the most significant acid load results from the hypoxic metabolism. The acidosis causes e.g. dilatation of cerebral vessels, facilitation of the entry of calcium ions into cells, loss of lysosomal latency and deranged production of ATP. The latter effect seems to impede parathormone-dependent calcium reabsorption in the kidney tubules. Besides, urinary acidification is affected by formic acid. Its excretion causes continuous recycling of the acid by the tubular cell Cl^?/formate exchanger. This sequence of events may partially explain an accumulation of formate in urine. Occupational exposure to vapours of methanol and formic acid can be quantitatively monitored by urinary formic acid determinations. Formic acid toxicity may prove a suitable model for agents causing histotoxic hypoxia.     

Work activity analysis of Finnish occupational health professionals

BACKGROUND: Some Finnish studies have dealt with how occupational health nurses divide their working hours but other occupational health professionals have not been evaluated. AIMS: This study describes how occupational health professionals allocate their working hours between main tasks. METHODS: Questionnaires were sent to 250 occupational health professionals, of whom 176 (70%) returned the completed forms. The data were analysed by using frequencies, means and one-way analysis of variance test. RESULTS: Employee-oriented tasks accounted for roughly 50% of working hours from all occupational health professionals. The remaining working hours were shared between workplace visits, co-operation with partners, other occupational health care responsibilities and tasks in other health care fields, especially in the health care centres. These working hours varied greatly between the different occupational health professional groups. All units employed full-time occupational health nurses, but the services of physicians, physiotherapists and psychologists were usually provided part-time or even restricted to a few hours each week because these services were difficult to obtain. Occupational health nurses working in the municipal health care centres spent more time on workplace visits than other nurses. Employee-oriented tasks were emphasized more in physicians', physiotherapists' and psychologists' work, especially in private medical health care units and in the jointly owned health care units. CONCLUSIONS: The amount of time occupational health professionals are able to spend on workplace activities appears to be determined by the type of their employer.     

Antibody response to 7-valent conjugated pneumococcal vaccine in patients with chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is a common adulthood mature B-cell neoplasm. Infections are the most important cause of mortality in this condition, and Streptococcus pneumoniae has been considered the most important single pathogen. We investigated the immunogenicity of 7-valent pneumococcal conjugate vaccine in patients with CLL. The study material comprised 52 patients with CLL and 25 age- and sex-matched controls. The subjects were vaccinated with Prevenar pneumococcal conjugate vaccine. Serum samples were taken for antibody determinations before and four weeks after vaccination. Antibody response rates to vaccine antigens were lower in patients with CLL compared to controls. However, if the vaccine had been administered at an early stage of the disease, i.e. before commencement of chemotherapy and the development of hypogammaglobulinaemia, a significant vaccination response to at least six antigens was obtained in almost 40% of the CLL patients. Our results indicate that early administration of conjugate vaccine may be beneficial in CLL.