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PubMed1999

American cutaneous leishmaniasis in Southeast Brazil: space-time clustering.

BACKGROUND: American cutaneous leishmaniasis (ACL) is endemic in many rural areas of Brazil where different transmission patterns of the disease have been described. This ecological study was carried out in a municipality located in Southeast Brazil and aimed to investigate the space-temporal patterns of the disease and environmental risk factors from 1966 to 1996. METHODS: Incident ACL cases were defined by clinical diagnosis, confirmed by a positive skin test and/or parasitological examination. Age-adjusted morbidity rate of ACL was calculated by year for this municipality and their different census enumeration districts. The homogeneity chi2 test, Moran and empirical Bayes index and Knox procedure were employed for testing the significance of clusters in time, space and in time-space, respectively. A Poisson regression model was used to identify environmental factors related to rate variability. RESULTS: A total of 1712 new ACL cases were reported with a yearly incidence rate of 48/100000 inhabitants. Higher incidence rates were detected in 1968, 1974, and 1988 (100, 160, and 190 cases/100000, respectively) with evidence of spatial clustering from 1986 to 1993. Significant space-time clustering with epidemic peaks followed by low incidence in subsequent periods was observed. The incidence rates of ACL were independently associated with rural areas; areas lacking sanitary installations and with higher proportion of exposed garbage (P < 0.01). CONCLUSIONS: This study suggests that ACL rates vary across space and time. Rural areas and some environmental factors could explain part of this variation. Environmental modifications in the vicinity of households over time and accumulation of susceptible individuals are discussed as possible factors responsible for variability.

Adult↗
PubMed2002

Widening the sphere of influence: using a tool to extend extrapersonal visual space in a patient with severe neglect.

We report evidence that visual representations of space close to the body can be extended when a patient uses a tool to explore the environment. HB had severe neglect of left and far spatial regions which was determined more by how locations were visually perceived than by how they were represented tactilely or through proprioception. His ability to detect visual targets in left and far space was improved, however, when he held a tool. He also had limited tactile/proprioceptive knowledge about the location of his hand. These data suggest that by holding a tool, HB's more intact representation of near, visual space could be extended to include stimuli presented at a distance from his body. This extension of space improved his detection of visual stimuli. We discuss the implications of the results for the nature of our internal representation of space.

Cognition Disorders↗
PubMed2006

Space dosimetry with the application of a 3D silicon detector telescope: response function and inverse algorithm.

One of the many risks of long-duration space flights is the excessive exposure to cosmic radiation, which has great importance particularly during solar flares and higher sun activity. Monitoring of the cosmic radiation on board space vehicles is carried out on the basis of wide international co-operation. Since space radiation consists mainly of charged heavy particles (protons, alpha and heavier particles), the equivalent dose differs significantly from the absorbed dose. A radiation weighting factor (w(R)) is used to convert absorbed dose (Gy) to equivalent dose (Sv). w(R) is a function of the linear energy transfer of the radiation. Recently used equipment is suitable for measuring certain radiation field parameters changing in space and over time, so a combination of different measurements and calculations is required to characterise the radiation field in terms of dose equivalent. The objectives of this project are to develop and manufacture a three-axis silicon detector telescope, called Tritel, and to develop software for data evaluation of the measured energy deposition spectra. The device will be able to determine absorbed dose and dose equivalent of the space radiation.

Algorithms↗
PubMed1997

The effect of age on retrieval of local anesthetic solution from the epidural space.

UNLABELLED: We conducted this prospective study to determine whether advancing age is correlated with retrieval of local anesthetic solution from the epidural space. Three hundred forty-six patients (ASA physical status I or II, 20-93 yrs of age, 177 female and 169 male patients) undergoing epidural anesthesia were enrolled. The epidural space was identified by a loss of resistance technique using air, and a catheter was introduced 3 cm. Three milliliters of 2% lidocaine with epinephrine was injected as a study dose by hand at a rate of 1 mL/s with the patient in the supine position. The syringe was immediately aspirated to retrieve the local anesthetic solution. A retrieved volume of 0.5 mL or more with a glucose concentration less than 6 mg/dL was defined as retrieval positive, and a volume of less than 0.5 mL was defined as retrieval negative. There was a significant correlation between age and retrieval volume among all the patients (Y = 0.008X-0.222, P < 0.0001) with a significant increase in the positive retrieval incidence and volume from the patients in their 50s (11%, 0.6 +/- 0.3 mL) to the patients in their 60s (26%, 1.0 +/- 0.6 mL) (P < 0.05 for both). The incidence of positive retrieval and the retrieval volume were greater in the patients in their 60s and older (30%, 1.1 +/- 0.63 mL) than in the younger than 60 (10%, 0.6 +/- 0.3 mL) (P < 0.0001 and P < 0.001). The glucose concentration was 2.3 +/- 1.2 mg/dL in the positive cases. We conclude that there is a weak positive correlation between age and the local anesthetic solution retrieved from the epidural space. IMPLICATIONS: We conducted a study in 346 patients to determine whether advancing age could be correlated with retrieval of local anesthetic solution from the epidural space. We found a weak positive correlation between advanced age and the amount of solution retrievable from the epidural space. Further studies are required to determine whether this phenomenon may call for dose adjustments in patients aged more than 60 yrs.

Adult↗
PubMedDate not supplied

Continuation of gas from the right perirenal space into the bare area of the liver.

PURPOSE: It is difficult to explain some CT findings pertaining the anatomic relationship between the bare area of the liver and the right retroperitoneal space on the basis of the traditional three compartment concept of retroperitoneal anatomy. The purpose of this article is to ascertain and illustrate possible communication between the bare area of the liver and the right perirenal space in patients with gas-forming retroperitoneal infection. METHOD: We reviewed CT findings in 24 cases with retroperitoneal gas-forming condition with particular emphasis on the extent of the infection and resultant distribution of gas. RESULTS: CT images showed gas within the right perirenal space extended upward directly into the bare area of the liver in six cases. CONCLUSION: The right perirenal space is considered open toward the bare area of the liver. Therefore, gas within the perirenal space may communicate directly with the bare area of the liver.

Emphysema↗
PubMed1996

Destruction of newly released red blood cells in space flight.

Space flight results in a rapid change in total blood volume, plasma volume, and red blood cell mass because the space to contain blood is decreased. The plasma volume and total blood volume decreases during the first hours in space and remain at a decreased level for the remainder of the flight. During the first several hours following return to earth, plasma volume and total blood volume increase to preflight levels. During the first few days in space recently produced red blood cells disappear from the blood resulting in a decrease in red blood cell mass of 10-15%. Red cells 12 d old or older survive normally and production of new cells continues at near preflight levels. After the first few days in space, the red cell mass is stable at the decreased level. Following return to earth the hemoglobin and red blood cell mass concentrations decrease reflecting the increase in plasma volume. The erythropoietin levels increase responding to "postflight anemia"; red cell production increases, and the red cell mass is restored to preflight levels after several weeks.

Adaptation, Physiological↗
PubMed1996

When vitreous enters the subretinal space. Implications for subretinal fluid protein.

PURPOSE: Vitreous enters the subretinal space in rhegmatogenous detachments, but the protein concentration in subretinal fluid from clinical detachments is much higher than in vitreous. These experiments were designed to study short-term changes in subretinal albumin concentration after vitreous enters the subretinal space. METHODS: Retinal detachments were made in Dutch rabbits by injecting autologous liquefied vitreous (albumin concentration 244.11 micrograms/ml) into the subretinal space through a micropipette. Subretinal and vitreous fluid samples were withdrawn 0 to 4 hours later and analyzed for albumin concentration (by gel electrophoresis) and osmolality. The authors also made detachments with Hanks' balanced salt solution containing an approximate vitreal level (294.8 micrograms/ml) of fluorescein isothiocyanate albumin. RESULTS: When the authors made detachments using autologous liquefied vitreous, the subretinal albumin concentration increased to 333.3 micrograms/ml 4 hours after detachment, by which time the detachment volume had fallen to 65% of its initial level. The total amount of albumin in the subretinal space did not change significantly. Subretinal fluid osmolality remained within the range of 292 to 294 mOsm/kg despite the steady absorption of fluid from the detachment. The results were essentially the same when detachments were made with saline and fluorescein isothiocyanate albumin rather than vitreous itself. CONCLUSIONS: The subretinal concentration of albumin increases as water in subretinal fluid is absorbed across the retinal pigment epithelium. If liquefied vitreous continues to enter the subretinal space, as occurs in clinical cases of rhegmatogenous retinal detachment, this mechanism may cause albumin to accumulate.

Absorption↗
PubMed2004

Stimulation of the semicircular canals via the rotary chair as a means to test pharmacologic countermeasures for space motion sickness.

OBJECTIVE: Space motion sickness is currently treated pharmacologically with the empiric use of the H1 antihistamine promethazine, but use of this intervention is limited by the side effect of significant sedation. This creates a dilemma, as full cognition is particularly important during the same conditions likely to exacerbate the symptoms of space motion sickness. Using overstimulation of the semicircular canals with a rotary chair as a paradigm for space motion sickness, we evaluated four medications, commonly used for the treatment of terrestrial motion sickness and vertigo, for their efficacy in alleviating the simulated symptoms of space motion sickness. STUDY DESIGN: Randomized, prospective, double-blind study. SETTING: Tertiary referral center. PATIENTS: Healthy male and female volunteers, 18 years of age or older, without history of neurologic or psychiatric disorders, and with no known allergies or any previous adverse reactions to the drugs used. INTERVENTIONS: Lorazepam 1 mg, meclizine 25 mg, promethazine 25 mg, scopolamine 0.4 mg, or placebo. MAIN OUTCOME MEASURE: The ability of each treatment to control the nausea and vomiting associated with our paradigm for space motion sickness was evaluated by measuring time of rotation pre- and posttreatment and time of symptom onset pre-and posttreatment. RESULTS: Only scopolamine effected a mean change in duration of rotation that reached statistical significance when compared with placebo (p <0.008), with a greater than 40% increase in rotation time. Results with promethazine were not statistically significant. CONCLUSION: Results showed a rank order of efficacy of scopolamine > promethazine > placebo > meclizine > lorazepam. Scopolamine significantly increased rotation time, but none of the treatments resulted in a significant delay to onset of symptoms.

Adolescent↗
PubMed2003

Intraspinal synovial cyst communicating with the C1-C2 facet joints and subarachnoid space associated with rheumatoid atlantoaxial instability.

STUDY DESIGN: The first case of intraspinal synovial cyst communicating with the C1-C2 facet joints and subarachnoid space associated with rheumatoid atlantoaxial instability is presented. OBJECTIVES: To describe the diagnosis and successful treatment of a synovial cyst of the C1-C2 junction in a patient with rheumatoid arthritis and atlantoaxial instability. SUMMARY OF BACKGROUND DATA: Intraspinal synovial cysts of the C1-C2 junction are extremely rare. Neither association with rheumatoid atlantoaxial instability nor communication with the C1-C2 facet joints and the subarachnoid space has been previously reported in a synovial cyst of the C1-C2 junction. MATERIALS AND METHODS: The clinical and radiologic features of a 71-year-old woman with a symptomatic synovial cyst of the C1-C2 junction with rheumatoid atlantoaxial instability are detailed. Posterior atlantoaxial fusion alone was performed. RESULTS: Preoperative magnetic resonance images demonstrated a large cystic mass around the dens, compressing the spinal cord. The mass was of low signal intensity on T1-weighted images, was of high signal intensity on T2-weighted images, and was enhanced marginally with gadolinium-DTPA on T1-weighted images. Computed tomograms performed after myelography disclosed the cyst around the dens communicating with the subarachnoid space and the C1-C2 facet joints. Spontaneous regression of the cyst was identified on the magnetic resonance images 3 months after surgery. One year after surgery, myelopathic symptoms were improved. CONCLUSION: An intraspinal cyst communicating with the C1-C2 facet joints and subarachnoid space associated with rheumatoid atlantoaxial instability was reported. Computed tomograms after myelography were useful in delineating the relationships among the synovial cyst, facet joints, and the subarachnoid space. Spontaneous regression of the cyst and clinical improvement were achieved by C1-C2 posterior fusion alone.

Aged↗
PubMed2006

Contrast flow characteristics in the cervical epidural space: an analysis of cervical epidurograms.

STUDY DESIGN: A single-center prospective analysis of cervical epidurograms, using a crossover design. OBJECTIVES: To delineate the extent and pattern of spread of epidural contrast during cervical epidural steroid injections. To determine the volume of solution needed for effective cervical epidural steroid injections. To determine the most appropriate neck flexion angles for cervical epidural steroid injections. To determine the relationships between epidural spread, degree of neck flexion, and volume of solution used during cervical epidural steroid injections. SUMMARY OF BACKGROUND DATA: The decreased epidural space in the cervical region makes injections here liable to rare, but potentially serious, complications. The lower cervical (C6-C7, C7-T1) levels are thought to be safer because of the increased epidural space here, as compared with higher levels. There is, however, considerable controversy in the scientific literature regarding the levels at which cervical epidural injections should be performed. There is also no consensus regarding the volume of solution needed or the extent of neck flexion required for effective epidural spread. To date, no study has examined these questions. METHODS: Patients with lower cervical spine pathology who were referred for cervical epidural steroid injections were randomly assigned to have the injections performed at the C6-C7 or C7-T1 midline level. Volume of solutions used and degree of neck flexion were measured. Characteristics of epidural spread were recorded. Patients requiring repeat injections had the injections performed at the adjacent level with identical volume and angle of neck flexion using a goniometer. Contrast flow characteristics were again recorded. Extent of spread was correlated with the level of injection, volume of injectant, and degree of neck flexion. RESULTS: No major or permanent complications were noted. The contrast was found to spread evenly throughout the entire dorsal cervical epidural space, on a consistent basis, in all cases. At C6-C7, it was found to spread an average of 3.61 +/- 0.84 levels; and at C7-T1, it spread an average of 3.88 +/- 1.01 levels. Using a three-way analysis of variance, the level at which the epidural was performed, the amount of contrast used, and the neck flexion angle did not affect the number of levels spread. CONCLUSIONS: In cervical epidural steroid injections performed in the midline at C6-C7 and C7-T1, the contrast consistently covers the dorsal cervical epidural space bilaterally, irrespective of the volume used or neck flexion angle used. This suggests that solutions introduced here would cover the dorsal cervical epidural space. This questions the utility of performing potentially more dangerous injections at higher cervical levels or more invasive procedures, such as the use of epidural catheters.

Cervical Vertebrae↗
PubMed1979

Membrane potential and ion concentration stability conditions for a cell with a restricted extracellular space.

For an isolated membrane, the resting (zero current) potential is stable is the slope conductance is positive, and is unstable if the slope conductance is negative. Recent work suggests that the properties of many preparations are influenced by the presence of an extracellular space that is not in good diffusive contact with the bulk extracellular fluid. Ionic current flow across the membrane changes the ion concentrations in this space. These concentration changes affect the stability of the membrane potential. Even if the slope conductance is negative, the presence of the extracellular space can confer stability on the resting potential. Conversely, even if the slope conductance is positive, the extracellular space can produce instability of the resting potential. Evaluation of the relevant parameters for cardiac Purkinje fibres, from published experimental data, suggests that concentration changes in the extracellular space may play a significant role in determining when an action potential is initiated.

Animals↗
PubMed2006

Through the Iron Curtain: analytical space in post-Soviet Russia.

This paper discusses the experience of working as an analyst in post-totalitarian Russia in order to explore some of the general theoretical and clinical issues involved in working in a different cultural and linguistic context, and the particular problems encountered in the Russian cultural context. It describes how the Soviet regime worked actively to create a new totally collective mentality through the destruction of individual differences and the collectivization of private space, and the effects this produced in the individual and collective psyche. It examines the difficulties encountered when working with Russian analysands in creating and maintaining the setting, in preserving boundaries, in creating analytical space, and in working with certain particular transference-countertransference dynamics. It focuses on the contrast between my own Western experience of space and the spatial experience of the analysands, and describes the process of helping them use analytical space to interiorize and create a new experience of psychic space. The paper uses dreams to illustrate some of these dynamics, and the particular psychic problems associated with the traumas created by totalitarian regimes.

Culture↗
PubMed2005

Nanostructure of the epidermal extracellular space as observed by cryo-electron microscopy of vitreous sections of human skin.

The newly developed method, cryo-electron microscopy of vitreous sections, was used to observe the nanostructure of the epidermal extracellular space. The data were obtained from vitreous sections of freshly taken, fully hydrated, non-cryo-protected human skin. The extracellular space of viable epidermis contains desmosomes, expressing a characteristic extracellular transverse approximately 5 nm periodicity, interconnected by a relatively electron lucent inter-desmosomal space. The extracellular space between viable and cornified epidermis contains transition desmosomes at different stages of reorganization interconnected by widened areas expressing a rich variety of complex membrane-like structures. The extracellular space of cornified epidermis contains approximately 9, approximately 14, approximately 25, approximately 33, approximately 39, approximately 44, and approximately 48 nm thick regions in turn containing one, two, four, six, eight, eight, and ten parallel electron-dense lines, respectively, between adjacent corneocyte lipid envelopes. The eight-line approximately 44 nm thick regions are most prevalent.

Adult↗
PubMed2001

Fungal flora on board the Mir-Space Station, identification by morphological features and ribosomal DNA sequences.

This report is on the morphological and molecular biological identification, using 18S- and ITS1-rDNA sequences, of the "space fungi" isolated on board the Russian Mir-Space Station as the major constituents of the fungal flora. The six fungal strains were isolated from air by using an air sampler or from condensation. Strains were identified as Penicillium chrysogenum, Aspergillus versicolor, or Penicillium sp. by both methods. The species of space fungi were common saprophytic fungi in our living environment, potential pathogens, and allergens. This study concluded that the environment on board the space station Mir allows the growth of potentially pathogenic fungi as true in residential areas on the earth. Therefore, to prevent infection or other health disorders caused by these fungi, easy and reliable methods should be established to survey the fungal flora in a space station.

Aspergillus↗
PubMed1981

Epidural space pressures during pregnancy.

The epidural space pressure in the lumbar region was monitored and recorded in 21 full term pregnant patients, before and during labour and 6-12 hours postpartum, in different positions. The pre-labour epidural pressure was found to be above atmospheric in all patients, being highest when supine, and lowest in the lateral position. Three patients with twin pregnancy showed a greater rise in epidural space pressure in the supine position even with the use of lateral tilt, compared with patients with single fetus pregnancy. It is suggested that the epidural space pressure in the full term pregnant patient is closely related to the degree of inferior vena caval obstruction imposed by the gravid uterus. It is also suggested that when the patient is aware of a uterine contraction, the synchronous rise of the epidural space pressure with the contraction is a result of reflex increase in abdominal muscle tone. With established epidural block, and the parturient unaware of a contraction, such a rise was minimal, and was replaced by a drop in pressure in patients with a single fetus who developed loss of muscle power. The magnitude of the drop in the epidural space pressure immediately after delivery was found to be related to the duration of labour and to the mode of delivery. Epidural pressures measured 6-12 hours after delivery were comparable in all patients.

Anesthesia, Epidural↗
PubMed1984

Influence of fixative osmolality on the morphometric determination of extracellular space in normal and reperfused ischaemic myocardium.

Morphometric determination of extracellular space in control and post-ischaemic reperfused rabbit myocardium was evaluated using two fixatives differing in their composition and total osmolality. Measurement of control extracellular space in an isotonic fixative (294 mOsm/kg water) was 20.8% and in a hypertonic fixative (1816 mOsm/kg water) was 22.2%. These values were not statistically different. Ischaemic durations of 15, 30, 60 and 90 min, followed by an equivalent period of reperfusion, created significant increases in extracellular space. The size of the extracellular space determined by both fixatives was found to be the same. Total fixative osmolality does not appear to influence morphometric evaluation of the extracellular space in control tissue or in tissue damaged by ischaemia and reperfusion.

Animals↗
PubMed2000

Alveolar dead space as a predictor of severity of pulmonary embolism.

OBJECTIVE: To determine whether the alveolar dead space volume (V(D)alv), expressed as a percentage of the alveolar tidal volume (V(D)alv/V(T)alv), can predict the degree of vascular occlusion caused by pulmonary embolism (PE). METHODS: Fifty-three subjects with suspected PE were prospectively studied. Pulmonary embolism was diagnosed in 33 by high-probability ventilation/perfusion (V/Q) scan (n = 19) or by pulmonary arteriography (PAG, n = 14). Pulmonary embolism was excluded by PAG in 20 subjects. The V(D)alv/V(T)alv was determined from volumetric capnography and arterial blood gas analysis, which permits measurement of the physiologic dead space, V(D)phys (mL) = [(PaCO2 - PeCO2)/PaCO2]. tidal volume. Airway dead space (V(D)aw) was subtracted to yield the alveolar dead space [(V(D)phys - V(D)aw) = V(D)alv (mL)]; the percentage of alveolar volume occupied by alveolar dead space per breath = V(D)alv/V(T)alv x 100%. Percentage perfusion defect was determined from V/Q scans by a radiologist blinded to other data. Regression analysis was performed to show correlation between V(D)alv/V(T)alv and defect on V/Q scan or systolic pulmonary arterial pressure (SPAP). RESULTS: For subjects with PE, the mean perfusion defect on lung scan was 38 +/- 22%; the mean V(D)alv = 208 +/- 115 mL, V(T)alv = 452 +/- 251 mL, and V(D)alv/V(T)alv = 43 +/- 18%. Regression of V(D)alv/V(T)alv vs perfusion defect yielded r2 = 0.41. Regression of V(D)alv/V(T)alv vs pulmonary artery pressures yielded r2 = 0.59. For subjects without PE, V(D)alv/V(T)alv = 27 +/- 14% and V(D)alv = 89 +/- 66 mL. CONCLUSIONS: The V(D)alv/V(T)alv correlates with the lung perfusion defect and the pulmonary artery pressures in subjects with PE. These findings show the potential for V(D)alv/V(T)alv to quantify the embolic burden of PE.

Adult↗
PubMed1979

Potassium activity in photoreceptors, glial cells and extracellular space in the drone retina: changes during photostimulation.

1. A double-barrelled potassium-sensitive micro-electrode was developed that was fine enough to record intracellular electrical potentials and potassium activities (aK) in the drone retina. 2. aK was measured in the photoreceptor cells, in the pigment (glial) cells, and in the extracellular space, in the superfused, cut, retina. The effect of photostimulation was studied: 20 msec light flashes, intense enough to evoke receptor potentials of maximum amplitude were presented, 1/sec, in a train lasting about 2 min. 3. In photoreceptors with membrane potentials greater than or equal to 50 mV aK in the dark was 79 mM, S.D. = 27 mM, n = 11. During photostimulation aK fell by 21.5 +/- 9.5 mM with a half-time of 30 +/- 22 sec. (A tentative conversion from activities to free concentrations can be made by taking the activity coefficient as 0.70 its value in the Ringer solution). 4. In pigment cells with membrane potentials greater than or equal to 50 mV, aK in the dark was 52 mM, S.D. = 13 mM, n = 11. During photostimulation aK increased by 14 +/- 5 mM. 5. In the extracellular space aK increased during photostimulation with a mean half-time of less than 1.3 sec to a maximum (mean value 14 mM, S.D. = 8.4 mM, n = 22), and then fell to a plateau. 6. It is estimated from the anatomy that the photoreceptors occupy approximately 38% of the total volume of the retina, the pigment cells 57%, and extracellular space 5%. Hence, it seems possible that during photostimulation nearly all the net loss of potassium from the photoreceptors is temporarily stored in the pigment cells. 7. Recordings were made in the extracellular space of the intact animal by passing the electrode through a hole in the cornea. The mean aK in the dark was 7.7 mM, S.E. = 0.4 mM, n = 22. In the superfused retina, aK in the dark was 6.3 mM, S.E. = 0.7 mM, n = 22, even though aK in the Ringer solution was 2.2 mM. Increasing the aK of the Ringer solution to 7.0 mM had no apparent effect on aK in the extracellular space at depths greater than 20 micron. 8. In the intact animal the amplitude and time course of the change in extracellular aK evoked by the standard pattern of photostimulation were within the range observed in the superfused preparation.

Animals↗