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PubMedDate not supplied

[Ultrasonography of changes in the retroperitoneal vessels and perivascular spaces during retroviral infection: preliminary results].

The abdomen in patients with acquired immunodeficiency syndrome (AIDS) is subject to various damage. In AIDS patients, manifestations in the retroperitoneal region, including apparent changes in the pancreas, kidney and lymph nodes, have been well described in the radiological literature. However, abnormalities of the vessels and perivascular spaces have not been well investigated in this syndrome. We performed abdominal sonography in 10 patients who were seropositive for HIV. They had no history of known risk factors such as drug abuse or homosexuality. Also, 4 healthy male controls were examined for comparison. Our aim was to demonstrate and to characterize the pathological changes of the retroperitoneal vessels and perivascular spaces from sonographic observations. The sonographic evaluation included determination of the morphologic and dynamic aspects of the aorta, vena cava and superior mesenteric vessels. The echostructure of the perivascular spaces was analyzed. In this prospective and preliminary study, we have not considered the presence of an AIDS condition. We have precisely analyzed the upper umbilical areas. In all cases, there were supposed to be the same landmarks. The sonographic scans were obtained through the left renal and mesenteric vessel areas, essentially through axial scans. In all 10 patients, sonography showed at least two abnormalities. Three patients had abnormal echostructural changes in all the sites. The images showed echostructural disorganization with poor definition and "fuzzy" and "dirty" aspects of the retroperitoneal vessels and perivascular spaces. The aorta was normal in 2 patients and abnormal in 8 patients with diminished hyperechography and regularity of the aortal wall. The aortic diameter was smaller than 1.5 cm in 7 cases, with a significant attenuation of the beating of the aorta. Despite these abnormalities, the aorta had a normal left paramedian position ahead of the rachis. The inferior vena cava was normal in 1 case and abnormal in 9 cases with diminished hyperechography and regularity of the wall. The vena cava position was normal in 4 cases, displaced in 6, and laminated in 3. The superior mesenteric vessels were abnormal in 8 cases, with poorly defined aims in 6, an indefinite position in 2, and spreading in 2. Adenopathy was present in 6 patients, multiple in 5 and singular in 1 case. A retrocaval location was always observed. A perivascular infiltration and thickening was noted which was diffuse in 6 cases and micronodular in 1 case. From our observations, we conclude that these echostructural changes could be related to AIDS. However, further studies are necessary to confirm these observations and to determine if this sonographic pattern may be seen during the course of the disease. This is the first study to our knowledge which stressed the echostructural changes of the retroperitoneal vessels and perivascular spaces in patients with AIDS.

Abdomen↗
PubMed1997

Craniad migration of differing doses of new methylene blue injected into the epidural space after death of calves and juvenile pigs.

OBJECTIVE: To determine the relation between epidural injectate volume (ml/kg of body weight) and its craniad migration in calves and pigs. ANIMALS: 23 neonatal calves and 26 feeder pigs. PROCEDURE: Animals were randomly assigned to receive different volumes of new methylene blue (NMB, 1.2 mg/ml in 0.9% saline solution). Injections were made into the sacrococcygeal intervertebral space in calves and the lumbosacral intervertebral space in pigs, immediately after euthanasia. Sagittal sections of the spine were made at necropsy, and craniad migration of NMB was determined and rounded to the nearest intervertebral space. RESULTS: In calves treated with 0.05, 0.1, or 0.15 ml of NMB/kg, mean +/- SEM number of stained spinal segments was 5 +/- 0.3, 8 +/- 0.6, and 8 +/- 0.6, respectively. Craniad migration of NMB was significantly greater for 0.15 and 0.1 ml/kg volumes versus 0.05 ml/kg. In pigs treated with 0.05, 0.1, 0.2, of 0.3 ml of NMB/kg, mean number of stained spinal segments was 8 +/- 1.1, 8 +/- 0.9, 10 +/- 1.2, and 18 +/- 2.0. Craniad dye migration was significantly greater in the 0.3 ml/kg group versus the 3 lower volume groups. Linear regression performed on both sets of data after logarithmic transformation of spaces migrated to correct for non-normality was significant (P < 0.05), and R2 values of 0.49 and 0.55 were obtained for calves and pigs, respectively. CONCLUSIONS: There is a significant correlation between volume (ml/kg) of NMB injected in the epidural space and its craniad migration in calves and pigs. CLINICAL RELEVANCE: Results provide a basis for determination of volume of injectate to be given to reach a minimal desired level and should be a useful baseline for future investigations of epidural drug administration.

Anesthesia, Epidural↗
PubMed1976

[Production and absorption rate of cerebrospinal fluid in the spinal subarachnoid space of the dog (author's transl)].

Adult mongrel dogs, weighing 10-17 kg. were anesthetized with Nembutal and cervical and lumbosacral laminectomy was performed. The spinal subarachnoid space was blocked by extradural ligation at the level of the C4 to interrupt CSF communication between the cranial and spinal space. Polyethylene catheters were placed in the cervical and lumbosacral subarachnoid space, and artificial Mock CSF buffer, pH 7.35-7.40, containing inulin of 25 mg/dl or 14C-inulin of 1.5-2 muCi/dl as a tracer was perfused in the sacro-cervical direction through the catheter. After a steady state of perfusion was acommplished, the CSF was collected from the outlet catheter. Production and absorption rate of the CSF were calculated after Pappenheimer and Heisey's equation. 1) Effects of CSF pressure on the rate of production (Vf) and absorption (Va) of CSF and on the difference between outflow fluid rate (Vo) and inflow fluid rate (Vi) were studied within the pressure range of -100 to +600 mmH2O. Then, regression lines were calculated by means of the least square method. See Article. Vf was little affected by changes in CSF pressure, while Va increased linearly as CSF pressure elevated. This suggests that the spinal subarachnoid space plays an important role as a site of CSF absorption when the intracranial pressure increases. Vo-Vi, that is difference between absorption and production rate, decreased linearly as the CSF pressure increased. 2) Under a constant CSF pressure of +200 mmH2O, the effects of glucocorticoids (dexamethasone, 0.25 mg/kg and hydrocortisone, 4.15 mg/kg) and a carbonic anhydrase inhibitor (acetazolamide, 10 mg/kg) upon the production and absorption rate of CSF were determined 1/2, 1, 2 and 3 hours after intravenous administration. a) Effect of dexamethasone: The rate of CSF production was reduced to 60.5 +/- 2.4% (p less than 0.001) of the control level. The absorption rate of CSF also decreased to 59.2 +/- 6.09% (p less than 0.001) of the control. b) Effect of hydrocortisone: The production rate of CSF decreased to 67.4 +/- 6.61% (p less than 0.001), and the absorption rate to 76.5 +/- 3.94% (p less than 0.001) of the control level. c) Effect of acetazolamide: The production and absorption rate also decreased to 57.2 +/- 5.61% (p less than 0.001) and to 56.9 +/- 7.02% (p less than 0.001), respectively. 3) Pentration of tritiated dexamethasone and tritiated hydrocortisone from plasma to CSF. The penetration of tritiated dexamethasone and tritiated hydrocortisone from plasma to CSF in the spinal and cranial subarachnoid space was observed after the intravenous administration. The CSF/Plasma ratio of dexamethasone was 30.9% at 15 minutes and gradually increased to 91.5% and 93.5%, respectively, in the cranial and spinal CSF at 3 hours after the injection.

Acetazolamide↗
PubMed1998

Transitional space in the treatment of immigrants.

This paper illustrates how the dimension of space is an apt arena for immigrant patients to play out their separation problems. A continuum is proposed in which the extreme ends represent pathological attitudes toward space. Two cases are presented to demonstrate how these differential approaches to space result in unique ways of dealing with separation and immigration. Treatment of immigrants involves the transformation of the therapeutic milieu into a transitional space to form a bridge between the patient's native country and current home and a potential space to allow patients to create new ways to view themselves and their worlds.

Acculturation↗
PubMed1998

Loss of space and dental arch length after the loss of the lower first primary molar: a longitudinal study.

The premature loss of primary teeth may harm the normal occlusal development, although there are debates relating to the necessity of using space maintainer appliances. The aim of the study is to evaluate the changes in the dental arch perimeter and the space reduction after the premature loss of the lower first primary molar in the mixed dentition stage. The sample consists of 4 lower arch plaster models of 31 patients, within the period of pre-extraction, 6, 12 and 18 months after the lower first primary molar extraction. A reduction of space was of noted with the cuspid dislocation and the permanent incisors moving toward the space of the extraction site. It was concluded that the lower first molar primary premature loss, during the mixed dentition, implicates an immediate placement of a space maintainer.

Child↗
PubMedDate not supplied

The longevity of space maintainers: a retrospective study.

METHODS: This retrospective study investigated the longevity of 301 space maintainers fitted in 141 patients aged 3.4-22.1 years in the Department of Pediatric Dentistry at Leeds Dental Institute between 1991 and 1995. RESULTS: Failure occurred in 190 space maintainers (63%), of which 36% were due to cement loss, 24% breakage, 10% design problems, and 9% were lost. Using the life table method, the median survival time (MST) for space maintainers was found to be 7 months. Band and loop (B&L) appliances had the highest MST of 13 months, while the lower lingual holding arch (LLHA) had the lowest of 4 months. Unilateral space maintainers survived longer than bilateral space maintainers (MST of 13 months vs. 5 months). Left B&Ls had a MST of 16 months, compared to only 4 months for right B&Ls, Gender, age, arch in which the appliance was placed, the operator planning it, fixed vs. removable, and adequacy of pretreatment assessment did not have a significant effect on survival time.

Adolescent↗
PubMed1987

Spacelab experiments on space motion sickness.

Recent research results from ground and flight experiments on motion sickness and space sickness conducted by the Man Vehicle Laboratory are reviewed. New tools developed include a mathematical model for motion sickness, a method for quantitative measurements of skin pallor and blush in ambulatory subjects, and a magnitude estimation technique for ratio scaling of nausea or discomfort. These have been used to experimentally study the time course of skin pallor and subjective symptoms in laboratory motion sickness. In prolonged sickness, subjects become hypersensitive to nauseogenic stimuli. Results of a Spacelab-1 flight experiment are described in which four observers documented the stimulus factors for and the symptoms/signs of space sickness. The clinical character of space sickness differs somewhat from acute laboratory motion sickness. However SL-1 findings support the view that space sickness is fundamentally a motion sickness. Symptoms were subjectively alleviated by head movement restriction, maintenance of a familiar orientation with respect to the visual environment, and wedging between or strapping onto surfaces which provided broad contact cues confirming the absence of body motion.

Adaptation, Physiological↗
PubMed1991

Neurosciences research in space: future directions.

Future research in the neurosciences can best be understood in the context of NASA's life sciences goals in the near term (1990-95), mid term (1995-2000), and long term (2000 and beyond). Since NASA is planning short-duration Spacelab and International Microgravity Laboratory (IML) flights for many years to come, the acute effects of exposure to microgravity will continue to be of experimental and operational interest in the near term. To this end, major new areas of research will be devoted to ground-based studies of preflight adaptation trainers and their efficacy in preventing or reducing the incidence of space motion sickness. In addition, an extensive series of studies of the vestibular system will be conducted inflight on the IML-1 mission The IML-2 mission will emphasize behavior and performance, biological rhythms, and further vestibular studies. In the mid-term period, Spacelab missions will employ new technology such as magnetic recording techniques in order to evaluate changes in the processing of sensory and motor inputs at the brainstem and cortical level during exposure to microgravity. Two Space Life Sciences (SLS) missions planned for the mid to late 1990's, SLS-4 and SLS-5, will utilize an onboard centrifuge facility that will enable investigators to study the effects of partial gravity on sensory and motor function. In the long term (2000 and beyond), Space Station Freedom and long-duration missions will provide opportunities to explore new options in the neurosciences, such as sensory substitution and augmentation, through the use of physical sensors to provide three-dimensional tactile-visual, tactile-auditory and tactile-somatosensory inputs. The use of this technology will be extremely important in the area of robotic telepresence. Finally, Space Station Freedom and proposed LifeSat missions will provide neuroscientists the opportunity to study the effects of partial gravity and microgravity on neuronal plasticity.

Centrifugation↗
PubMed1992

The space life sciences strategy for the 21st century.

In the past, space life sciences has focused on gaining an understanding of physiological tolerance to spaceflight, but, for the last 10 years, the focus has evolved to include issues relevant to extended duration missions. In the 21st century, NASA's long-term strategy for the exploration of the solar system will combine the assurance of human health and performance for long periods in space with investigations aimed at searching for traces of life on other planets and acquiring fundamental scientific knowledge of life processes. Implementation of this strategy will involve a variety of disciplines including radiation health, life support, human factors, space physiology and countermeasures, medical care, environmental health, and exobiology. It will use both ground-based and flight research opportunities such as those found in current on-going programs, on Spacelab and unmanned biosatellite flights, and during Space Station Freedom missions.

Aerospace Medicine↗
PubMed1989

Space medicine comes down to Earth.

Over the years innovative technologies developed for space flight have found their way into a variety of useful terrestrial applications. Significant examples can be found in the area of space medicine, which has greatly influenced human health care delivery on Earth. This report discusses several US applications of space medicine to terrestrial health needs and services, stressing the importance of a 'space applications mentality' as a valuable national asset.

Aerospace Medicine↗
PubMed1997

Identification and status of design improvements to the NASA Shuttle EMU for International Space Station application.

To meet the significant increase in EVA demand to support assembly and operations of the International Space Station (ISS), NASA and industry have improved the current Shuttle Extravehicular Mobility Unit (EMU), or "space suit", configuration to meet the unique and specific requirements of an orbital-based system. The current Shuttle EMU was designed to be maintained and serviced on the ground between frequent Shuttle flights. ISS will require the EMUs to meet increased EVAs out of the Shuttle Orbiter and to remain on orbit for up to 180 days without need for regular return to Earth for scheduled maintenance or refurbishment. Ongoing Shuttle EMU improvements have increased reliability, operational life and performance while minimizing ground and on-orbit maintenance cost and expendable inventory. Modifications to both the anthropomorphic mobility elements of the Space Suit Assembly (SSA) as well as to the Primary Life Support System (PLSS) are identified and discussed. This paper also addresses the status of on-going Shuttle EMU improvements and summarizes the approach for increasing interoperability of the U.S. and Russian space suits to be utilized aboard the ISS.

Environment, Controlled↗
PubMedDate not supplied

Psychological health maintenance on Space Station Freedom.

The scheduling of crew rotations for up to 180 days on Space Station Freedom presents a special challenge for behavioral scientists who are tasked with providing psychological support for the crews, their families, and mission flight controllers. Preflight psychological support planning may minimize the negative impact of psychological and social issues on mission success, as well as assist NASA management in making real-time mission planning decisions in the event of a significant social event (for example, the death of a family member). During flight, the combined psychological, emotional, and social stressors on the astronauts must be monitored, along with other aspects of their health. The Health Maintenance Facility (HMF) will have the capability of providing preventive, diagnostic, and therapeutic assistance for significant psychiatric and interpersonal problems which may develop. Psychological support will not end with the termination of the mission. Mental health professionals must be part of the team of medical personnel whose job will be to facilitate the transition--physical and mental--from the space environment back to planet Earth. This paper reviews each phase of mission planning for Space Station Freedom and specifies those factors that may be critical for psychological health maintenance on extended-duration space missions.

Astronauts↗
PubMedDate not supplied

Design and structural analysis of highly mobile space suits and gloves.

This paper evaluates the factors that control the flexibility of fabric space-suit elements, in particular gloves, by examining a bending model of a pressurized fabric tube. Results from the model are used to evaluate the design strategies used in space-suit components, to evaluate the current direction in research on highly mobile space-suit gloves and to suggest changes necessary for optimum glove fabric selection. Finally it is shown that the modulus of the fabric used in space-suit joint construction is as important to the flexibility of the joint as the glove size and design.

Astronauts↗
PubMed1997

Factors parents use in selecting play spaces for young children.

BACKGROUND: The amount of time children spend in play spaces (ie, physical locations that are appropriate for children's physical activity) near their homes is correlated with their level of physical activity. OBJECTIVE: To examine factors used in parents' decisions about the selection of play spaces for their children. SUBJECTS: Parents (primarily mothers) of 178 Mexican American and 122 white children who were a mean age of 4.9 years old at the first measurement. MEASURES: In individual interviews, parents rated 24 factors on their importance in selecting for their children a play space that is away from their home or yard. Decision factors were rated from 1 (ie, not important at all) to 5 (ie, very important). RESULTS: The most important factors, with ratings ranging from 4.8 to 4.2, were safety and availability of toilets, drinking water, lighting, and shade. Mexican American parents rated 8 of 24 items significantly higher than did white parents, including lighted at night, organized activities, play supplies, and drinking water. White parents rated 5 of 24 items significantly higher than did Mexican American parents, including distance from home, cost of admission, and child's friends go there. The rated importance of 7 of 24 items increased during 1 year, including play supplies, drinking water, distance from home, and parents' friends or relatives go there. CONCLUSIONS: These results indicate that parents can identify factors they use in selecting places for their young children to play, and selection factors differ somewhat by ethnicity or socioeconomic status. Further studies are needed to determine whether improvements on the most important selection factors might be effective in increasing the use of play spaces by children and their parents. Clinicians may be able to use the most highly rated decision factors to help parents assess the acceptability of play spaces in their areas.

Adult↗
PubMed2006

Birth spacing and risk of adverse perinatal outcomes: a meta-analysis.

CONTEXT: Both short and long interpregnancy intervals have been associated with an increased risk of adverse perinatal outcomes. However, whether this possible association is confounded by maternal characteristics or socioeconomic status is uncertain. OBJECTIVE: To examine the association between birth spacing and relative risk of adverse perinatal outcomes. DATA SOURCES: Studies published in any language were retrieved by searching MEDLINE (1966 through January 2006), EMBASE, ECLA, POPLINE, CINAHL, and LILACS, proceedings of meetings on birth spacing, and bibliographies of retrieved articles, and by contact with relevant researchers in the field. STUDY SELECTION: Included studies were cohort, cross-sectional, and case-control studies with results adjusted for at least maternal age and socioeconomic status, reporting risk estimates and 95% confidence intervals (or data to calculate them) of birth spacing and perinatal outcomes. Of 130 articles identified in the search, 67 (52%) were included. DATA EXTRACTION: Information on study design, participant characteristics, measure of birth spacing used, measures of outcome, control for potential confounding factors, and risk estimates was abstracted independently by 2 investigators using a standardized protocol. DATA SYNTHESIS: A random-effects model and meta-regression analyses were used to pool data from individual studies. Compared with interpregnancy intervals of 18 to 23 months, interpregnancy intervals shorter than 6 months were associated with increased risks of preterm birth, low birth weight, and small for gestational age (pooled adjusted odds ratios [95% confidence intervals]: 1.40 [1.24-1.58], 1.61 [1.39-1.86], and 1.26 [1.18-1.33], respectively). Intervals of 6 to 17 months and longer than 59 months were also associated with a significantly greater risk for the 3 adverse perinatal outcomes. CONCLUSIONS: Interpregnancy intervals shorter than 18 months and longer than 59 months are significantly associated with increased risk of adverse perinatal outcomes. These data suggest that spacing pregnancies appropriately could help prevent such adverse perinatal outcomes.

Birth Intervals↗
PubMed2000

Quantification of progressive joint space narrowing in osteoarthritis of the hip: longitudinal analysis of the contralateral hip after total hip arthroplasty.

OBJECTIVE: The rate of progressive joint space narrowing in the contralateral hip after total hip arthroplasty (THA) for osteoarthritis (OA) and the factors which may predispose patients to more aggressive joint space narrowing remain undefined. The current study sought to evaluate the rate and pattern of, and risk factors for, progressive joint space narrowing in the contralateral hip after THA for OA. METHODS: Each patient who underwent THA for OA in 1984-1985 was followed up longitudinally, and annual anteroposterior (AP) pelvis radiographs were obtained. The radiographic joint space width (JSW) of each contralateral hip joint was quantified, and the rates of JSW narrowing were determined. Evaluation of potential risk factors for accelerated progression of joint space narrowing included age, sex, side of surgery, weight, height, body mass index (BMI), hip pain, etiology of OA, and Kellgren/Lawrence radiographic grade. RESULTS: Ninety-nine patients and 619 AP pelvis radiographs were evaluated. The median initial JSW was 3.48 mm (interquartile range 1.55). JSW declined in a linear manner at a median rate of 0.10 mm/year. The rate of decline between baseline and followup in 20 months was predictive of the overall slope. Two subpopulations were identified. Eighty-five percent of patients maintained a slow decline in JSW (< or =0.2 mm/year), and 15% exhibited an accelerated decline in JSW (>0.2 mm/year). Kellgren/ Lawrence radiographic grade > or =2 and a diagnosis of primary OA were each associated with a more rapid decline in JSW (P = 0.006 and P = 0.02, respectively). Initial JSW, age, sex, weight, height, BMI, and hip pain were not risk factors for rapid decline in JSW. CONCLUSION: Radiographic hip JSW may be reliably quantified and followed up longitudinally using standard AP radiographs. Progression of JSW narrowing in the contralateral hip after THA for OA proceeds in a linear manner over several years. A subpopulation of patients with accelerated narrowing of contralateral JSW may be identified within 20 months, and may represent a suitable population with which to assess the potential efficacy of new disease-modifying agents.

Adult↗
PubMed1977

Three-dimensional studies on resorption spaces and developing osteons.

Resorption spaces and their continuations as developing osteons were traced in serial cross sections from decalcified long bones of dogs, baboons and a man, and from a human rib. Processes of formation of osteons and transverse (Volkmann's) canals can be inferred from three-dimensional studies. Deposits of new osseous tissue begin to line the walls of the spaces soon after termination of resorption. The first deposits are osteoid, usually stained very darkly by the silver nitrate procedure utilized, but a lighter osteoid zone adjacent to the canals occurs frequently. Osteoid linings continue to be produced as lamellar bone forms around them; the large canals of immature osteons usually narrow very gradually. Frequently they terminate both proximally and distally as resorption spaces, indicating that osteons often advance in opposite directions as they develop. Osteoclasts of resorption spaces tunnel preferentially into highly mineralized bone, and usually do not use previously existing canals as templates for their advance. Osteons evidently originate by localized resorption of one side of the wall of an existing vascular channel in bone, with subsequent orientation of the resorption front along the axis of the shaft. Advancing resorption spaces also apparently stimulate the formation of numerous additional transverse canal connections to neighboring longitudinal canals. Serial tracing and silver nitrate differential staining combine to reveal many of the processes of bone remodeling at work, and facilitate quantitative treatment of the data. Further uses in studies of bone tissue and associated cells are recommended.

Animals↗
PubMed2002

Functional gliding spaces of the dorsal side of the human hand.

The clinical and functional importance of gliding spaces of the hand (e.g., their role in the spread of infection or as a consideration in reconstructive surgery) has been repeatedly emphasized. However, only a few studies have provided details regarding the connective tissue spaces in the metacarpal region of the dorsal side of the human hand. The aim of the present study was to analyze the morphology and elucidate the anatomic relation of functional gliding spaces in the metacarpal region on the dorsal side of the human hand in order to provide a better understanding of function, and of clinical disorders and their treatment. To delineate these spaces we used a plastic (Acrifix 90) injection method. Twenty fixed and unfixed cadaver hands were subcutaneously injected with Acrifix 90 (a methacrylate) into the metacarpophalangeal transitional region and into the tendon sheaths of the extensor muscles. Different colors were used to distinguish one injected plastic solution from another. The spreading pattern of the injected medium was analyzed by careful dissection. To delineate the exact bordering structures and the topography of the injected spaces, two hands were plastinated using the E12/E6 technique (von Hagens et al., Anat Embryol 1987;175:411-421), and one hand was injected and embedded in Technovit 7100 for histological investigations. Injecting the plastic into the metacarpophalangeal transitional region of fingers II-IV in a disto-proximal direction, the solution spreads along the surface of the separate extensor tendons. It then coalesces 1-2 cm proximal to the injection points to form a continuous plastic plate, which protrudes between and on top of the previous injected tendon sheaths. In no case was a communication between the paratendinous tissue and the tendon sheaths observed. Laterally, the injected solution is delimited at the radial side of the extensor tendon of the second finger and at the ulnar side of the extensor tendon of the fourth finger. Using the described technique at the fifth finger yields a plastic plate that extends from the injection point to the tendon sheath. However, in two specimens a connection between the plastic injected into the tendon sheath of the fifth finger, and the distal injected solution was observed.

Cadaver↗