Tc-99m HMDP accumulation in primary peritoneal mesothelioma.
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Humans↗
Biomedical subjects
M A Gomez
Publications and source records attributed to M A Gomez.
Can the need for a physician as part of the pediatric transport team be predicted? A prospective study.
OBJECTIVES: To evaluate the quality of objective information obtained during telephone requests for the transport of pediatric patients. To evaluate the ability of subjective judgment, the Pediatric Risk of Mortality (PRISM) score, and the presence of tachycardia for age to predict the need for a physician on as a member of the pediatric transport team. DESIGN: Prospective data collection. SETTING: The pediatric transport program of a children's hospital. PATIENTS: All 129 infants and children transported over a 4-month period. MEASUREMENTS AND MAIN RESULTS: We defined an objective measure of the need for a physician's presence during the transport of a pediatric patient, based on either the necessity for procedural or medical interventions during the time of transport or on direct admission to the pediatric ICU after transport. At the time of initial telephone contact, a physician's subjective opinion of the need for physician presence was recorded, a PRISM score was derived, and the presence of tachycardia (adjusted for age) was determined. Subsequently, the vital signs recorded on the record of this request were compared with those vital signs charted at the referring hospital at the time of the initial telephone request. A total of 96% of vital signs obtained during the initial telephone contact were consistent with those percentages in the referring hospital medical records. Fifty (39%) of 129 transported patients required procedural or medical interventions or pediatric ICU admission. Subjective judgments predicted physician need with a high sensitivity (0.98), but with a low specificity (0.18). PRISM score predicted 62 (48%) of 129 transports to be "physician-required" (sensitivity = 0.72; specificity = 0.67). There was no statistical association between tachycardia for age and the objective need for a physician's presence. CONCLUSIONS: Objective information obtained during request for transfer was reliable. At the time of request for transfer, subjective judgment, PRISM score, and the presence of tachycardia did not predict the need for a physician presence during transport.
Child↗
Detection of Mycobacterium paratuberculosis antigen with colloidal immunogold in naturally infected sheep.
The anti-Mycobacterium paratuberculosis polyclonal serum is proved useful for labelling Mycobacterium paratuberculosis in glutaraldehyde-osmium-fixed and epon-embedded intestinal samples from sheep with clinical symptoms of paratuberculosis. M. paratuberculosis marked with antibody-coated colloidal gold stain was seen in macrophages, epithelioid cells, giant cells and neutrophils throughout intestinal mucosa. In large macrophages with a low lysosomal content, a great number of intact mycobacteria was seen within phagosomes. In macrophages with average lysosomal content, very few intact mycobacteria or mycobacterial debris were present and lysosome-phagosome fusions were observed. Mycobacteria within neutrophils were scanty. These results show the usefulness of colloidal immunogold techniques for studies of the pathogenesis of paratuberculosis.
Animals↗
Frequency of first-cousin marriages from civil marriage certificates in Argentina.
In Argentina information concerning relatedness of mates, especially first cousins, was introduced into the legal marriage certificate, record, and statistical report in 1968. The 1980-1981 biennial data, including 212,320 legal marriage reports, were analyzed for all of Argentina, subdivided into 22 states and 494 counties. The registered 0.373% of first-cousin marriages allows an estimate of consanguineous marriages of 0.629% and a mean inbreeding coefficient of alpha = 0.00031. This estimate lies between the observed alpha = 0.00011 from hospital births and alpha = 0.00052 from Roman Catholic Church dispensations. These differences are not large, and they may be due to sampling variations, indicating a low rate of inbreeding in Argentina. The frequency of first-cousin marriages in the 22 Argentine states is heterogenous, and 9 counties, representing 5 different regions, were identified as having a high rate of first-cousin marriage. Three of these were previously known as genetic isolates. A second series of data, including all 32,690 legal marriages registered in the state of Buenos Aires during the first half of 1984, showed a frequency of first-cousin marriages of 0.677%. First-cousin mates, compared with non-first-cousin mates, had a higher frequency of both mates being born in the same state of Buenos Aires and similar frequency distributions for age at marriage, single previous marriage status, level of education, and rate of unemployment. It is concluded that legal marriage data on consanguinity is reliable, inexpensive, universal, and enduring. The last two characteristics make them suitable for the survey of geographic clusters and time trends.
Argentina↗
Measurement of changes in ligament tension with knee motion and skeletal maturation.
This study was designed to determine the in situ strains, stresses, and loads in the medial collateral ligament (MCL) of skeletally immature and mature rabbits. Using a noncontact method, the magnitudes of the in situ strains were first determined as a function of knee flexion angle. The MCL was divided into three anatomical regions (anterior, middle, and posterior) across its width. For strain measurements, the variation of a gauge length in these regions was obtained in the intact knee at 60, 90, and 120 deg of flexion. Subsequently, all soft tissues around the knee were dissected away, leaving the femur-MCL-tibia (FMT) complex. The MCL was allowed to retract freely and the new length, called the zero length, was measured. From this, the in situ strains were determined. To obtain the stress-strain relationship of the FMT complex, the specimens were subjected to tensile testing. Knowing the in situ strains and the stress-strain relationship, the in situ stresses in the three anatomical regions of the MCL were determined as a function of knee flexion angle. Multiplying these stresses by 1/3 of the cross-sectional area and summing the loads thus calculated, the in situ loads of the MCL were obtained. Our data suggest that the in situ load in the MCL is not large within the range of knee flexion angles studied, i.e., 1.4 to 2.7 N for the skeletally immature animals and 3.0 to 5.8 N for the skeletally mature animals. An increase in the in situ load with skeletal maturation was demonstrated.
Animals↗
Effects of surgical treatment and immobilization on the healing of the medial collateral ligament: a long-term multidisciplinary study.
The long-term effects of surgical repair and immobilization on the healing of the transected medial collateral ligament (MCL) were studied biomechanically, biochemically and histologically in a canine model. Twelve adult canines were divided into two experimental groups and studied at 48 weeks postoperatively. For Group I, the transected MCL of the left knee was not repaired, and the joint was not immobilized. For Group II, the MCL was repaired and the joint was immobilized for six weeks. The right knee of each canine was sham-operated and served as the control. Histologically, the collagen fibers were less aligned in both of the experimental groups than in the controls. Furthermore, there were minimal differences in collagen and fibroblast alignment between the groups, although poorer alignment was observed for Group I at 12 weeks. Biochemically, the levels of types I and III collagen, reducible collagen cross-links and total collagen concentration for both groups returned to normal levels. Biomechanically, Group I achieved better results than Group II in terms of varus-valgus (V-V) knee rotation and ultimate load of the femur-MCL-tibia complex (FMTC), as these values returned to the level of controls. However, the mechanical properties of the healing MCLs did not compare well with the controls; the tensile strength was only 62% and 45% of controls for Groups I and II, respectively, at 48 weeks. These results suggest that conservative treatment (i.e., no surgical intervention) with early mobilization is better than surgical treatment with immobilization for an isolated Grade III MCL injury.
Animals↗
Cryptosporidium infection in renal transplant patients.
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Animals↗
Cytological, immunocytochemical and ultrastructural study of GH cells of pars distalis adenohipophysaria of kids (Capra hircus).
Staining and histochemical methods, immunocytochemical and electron microscopy were used to individualize the somatotropic or GH cells in the adenohypophyseal pars distalis of the kid. They are found in a sagittal section throughout the pars distalis constituting 34% of the hypophyseal cell population. They are 12.37 micron in size and have as an ultrastructural characteristic secretory spherical granules of a large size (males, 391 nm and females, 427 nm) which are very electrodense.
Animals↗
Cytological, immunocytochemical and ultrastructural study of the adenohypophyseal pars distalis of the kid (Capra hircus): the TSH cell.
The structure and ultrastructure of the adenohypophyseal pars distalis in kids of the Murciano-granadiana breed (18 males and 12 females), aged 2-3 months and with an average carcass weight of 8 kg has been studied. Techniques of staining (Tetrachrome Herlant's, and Cleveland-Wolfe) and histochemistry (PAS, PAS-OG and BA-PAS-OG) contrasted with immunolabelling (PAP) have been used. In addition an ultrastructural study has been made and nucleus and cytoplasm, secretory granules, mitochondria and lysosomes have been measured with a semiautomatic image analyzer (IBAS-1). TSH cells are found in sagittal section in the anterior area and in an antero-caudodorsal band, and transversally in the ventral and medial region; they are 6% and their average size is 14.15 microns. Ultrastructurally they are a single cellular type with spherical granules whose size is 195 nm in males and 149 in females; these granules are characterized by a clear halo and a variable electronic density. The rough endoplasmic reticulum is found as slightly enlarged vesicles with a homogeneous and moderately electro-dense content or in concentric stratifications.
Animals↗
Medical collateral ligament healing subsequent to different treatment regimens.
The response of transected canine medical collateral ligaments (MCL) to clinical treatment regimens was investigated. These regimens included no surgical repair with no immobilization and surgical repair with various periods of immobilization. The biomechanical, biochemical, and histological properties of the healing MCL were examined 6 and 12 wk postoperatively. At 6 wk, all healing MCLs had increased cellularity with decreased levels of total collagen and increased amounts of reducible Schiff base cross-links and type III collagen. Biomechanically, the varus-valgus (V-V) knee laxity was significantly increased, and no group achieved normal structural or mechanical properties. At 12 wk the histological appearance of the MCL became more normal but still had increased cellularity. Biochemically, the total collagen levels in experimental MCLs were not statistically different from the controls, but these MCLs still had high amounts of type III collagen and an even higher number of reducible cross-links. From knees in which the MCL was not treated, the V-V knee laxity and the ultimate loads of the femur-MCL-tibia complex achieved normal values. However, the stress-strain properties for these MCLs and those treated with repair and immobilization did not completely recover.
Animals↗
Holoprosencephaly and trisomy 21 in a child born to a nondiabetic mother.
This is the second reported case of a child with holoprosencephaly and trisomy 21. The first case was born to a diabetic woman; in our case, there was no evidence of diabetes in the mother. Most of the distinctive facial features of Down syndrome were obscured by the presence of cyclopia and a supraorbital proboscis in this infant. The relevance of chromosome analysis in cases with holoprosencephaly is discussed.
Abnormalities, Multiple↗
New experimental procedures to evaluate the biomechanical properties of healing canine medial collateral ligaments.
Both clinical and animal studies have indicated that early mobilization and exercise may improve the healing of injured medial collateral ligaments (MCLs). To investigate these effects, transected canine MCLs were subjected to three different treatment regimens: (a) no surgical repair with 6 weeks mobilization; (b) surgical repair with 3 weeks immobilization followed by 3 weeks remobilization; and (c) surgical repair with 6 weeks immobilization. After sacrifice, knee laxity was measured in a newly designed varus-valgus (V-V) laxity device. Each knee was tested subsequently in tension to determine the structural properties of the femur-MCL-tibia complex (FMTC) and the mechanical properties of the healing MCL substance. It was found that the V-V laxity increased for all experimental knees, but that early mobilization enhanced joint stability. The structural properties of the FMTC and the mechanical properties of the MCL substance were also lower than the contralateral controls. Again, the early mobilization groups had better results.
Animals↗
Effects of knee flexion on the structural properties of the rabbit femur-anterior cruciate ligament-tibia complex (FATC).
Many studies have been conducted to determine the biomechanical properties of the anterior cruciate ligament (ACL). The method of holding the femur-ACL-tibia complex (FATC) test specimen, the strain rate applied, the angle of knee flexion and the direction of the applied loads have an important effect on the outcome. It is felt that the tensile properties and strength of the ligament should be measured by applying the tensile force along the axis of the ligament. A versatile clamp was designed to accomplish this purpose. Fifty-seven rabbit knee specimens were tested at angles of flexion of 0 degrees, 30 degrees or 90 degrees. In addition, a comparative study of 25 pairs of rabbit legs were performed, whereby loading was either along the ligament or along the tibial axis. Cyclic hysteresis, ultimate load, energy absorbed, and stiffness were determined. The ultimate load values for the FATC decreased with increased knee flexion for those loaded along the tibial axis, while no such change was detected for FATC tested along the ligament axis. Other structural properties measured followed similar trends. It is concluded that the structural properties of the rabbit FATC change minimally with knee flexion (from 0 to 90 degrees) when loaded along the ligament axis, but decrease significantly with knee flexion when loaded along the axis of the tibia. Therefore, the data obtained in this field of study can be compared only if the direction of loading with respect to the ACL is similar.
Animals↗
Temperature dependent behavior of the canine medial collateral ligament.
The temperature dependent tensile behavior of ligament was investigated from 2 degrees C to 37 degrees C. Nondestructive cyclic tests were performed on ten canine femur-medial collateral ligament-tibia (FMT) complexes at sequential temperatures of 22 degrees C, 22 degrees C, 27 degrees C, 32 degrees C, 37 degrees C, and again at 22 degrees C. The samples were rested at zero load between tests for sufficient time periods to allow for full recovery from the ligament's time and history dependent viscoelastic properties. Ten additional FMT complexes were sequentially tested in a similar fashion, but at temperatures of 22 degrees C, 22 degrees C, 2 degrees C, 6 degrees C, 14 degrees C, and 22 degrees C. All canine FMT complexes showed temperature dependent viscoelastic properties: the measured area of hysteresis decreased with increasing temperature; the cyclic load relaxation behavior plateaued to a higher value at lower temperatures; and the tensile load at a predetermined ligament substance strain level had an inversely proportional relationship with respect to temperature.
Animals↗
The biomechanical and morphological changes in the medial collateral ligament of the rabbit after immobilization and remobilization.
The effects of immobilization and remobilization on the biomechanical and morphological properties of the femur-medial collateral ligament-tibia complex and each of its components were investigated in the rabbit. Specimens that had been obtained after periods of unilateral immobilization of the knee and remobilization were evaluated for structural properties. In addition, the mechanical properties of the substance of the medial collateral ligament and the histological characteristics of both the substance of the ligament and its sites of insertion were evaluated. After immobilization, there were significant reductions in the ultimate load and energy-absorbing capabilities of the bone-ligament complex, and an increased number of failures occurred by tibial avulsion. The tissue of the medial collateral ligament also became less stiff as a result of immobilization. Histologically, the femoral and tibial insertion sites showed increased osteoclastic activity, resorption of bone, and disruption of the normal attachment of the bone to the ligament. With remobilization, the ultimate load and energy-absorbing capabilities of the bone-ligament complex improved but did not return to normal. Failure by tibial avulsion became less frequent, and the stress-strain characteristics of the medial collateral ligament returned to normal. Histologically, the sites of insertion of the ligament also showed evidence of recovery.
Animals↗
Tensile properties of the medial collateral ligament as a function of age.
The biomechanical properties of the rabbit medial collateral ligament (MCL) as a function of maturation and age were investigated. Femur-MCL-tibia (F-M-T) preparations were obtained from rabbits of different age groups (open or closed epiphysis). Parallel increases in the animal body weight and ligament cross-sectional area were recorded with age. Cyclic and tensile failure tests were performed to obtain the structural properties of the F-M-T complex and the mechanical properties of the MCL substance. There were significant increases in the load at failure, energy-absorbing capability of the bone-ligament junction, and in the tensile strength of the ligament substance as a result of maturation and subsequent aging. Increases in the area of hysteresis obtained during cyclic loading-unloading were also documented. At the closing of the epiphysis, the mode of failure of the F-M-T structure progressed from tibial avulsion to failure in the midsubstance of the ligament. An asynchronous rate of maturation was observed between the structural properties of the bone-ligament complex and the mechanical properties of the ligament substance.
Aging↗
Less rigid internal fixation plates: historical perspectives and new concepts.
In the application of "rigid" plates for diaphyseal fractures, lack of callus healing and overprotection of the underlying bone are viewed by many investigators as undesirable consequences. Potential solutions offered to overcome these deficiencies include modification of the timing of plate removal, use of biologically degradable materials for plates so that stress-shielding can be minimized, and use of less rigid plate fixation systems. This study emphasizes the selection of appropriate design criteria for less rigid plate-fixation systems. To accomplish this goal, the axial, bending, and torsional stiffness parameters are considered in place of the oversimplified terms such as "flexible plate" or "elastic fixation." With the aid of finite element modeling and simplified bench experiments, we performed parametric studies and singled out the plate axial stiffness as the dominant factor in altering the bone stresses. As a result, we designed two experimental plates, one a thin Ti-6Al-4V (titanium with 6% aluminum and 4% vanadium) alloy plate with low stiffness in axial and bending directions, and the other a tubular stainless steel plate with low stiffness in the axial direction but moderate stiffness in bending and torsional directions. The low-stiffness Ti-6Al-4V alloy plate was first tested in a demanding bilateral canine midshaft osteotomy, and proved to be inadequate. Both experimental plates were successful in the unilateral osteotomies, with the tubular plate yielding the best results. After 6 months of plating, the bones beneath the tubular plate had superior mechanical and structural properties as compared to those of the control "rigid" stainless steel and the Ti-6Al-4V alloy plates. Application of this plate prolonged for 9 months did not cause reduction in bone properties and strength. The success of the tubular plate is due to its moderate bending and torsional stiffnesses, which provide adequate fixation to achieve callus union, while its low axial stiffness permits the underlying bone to share the physiological stresses needed for bone remodeling. These drastic changes in mechanical demands on the internal fixation plate during the early healing phase and the postunion remodeling phase are discussed.
Alloys↗
A new approach to the design of internal fixation plates.
Mathematical analysis by finite element modeling methods was used in conjunction with laboratory bench experiments in selecting appropriate stiffness parameters for internal fixation plate designs. Bench experiments performed included tests of an idealized plated magnesium tube and of a plated canine femur. Finite element modeling of the plate-tube and plate-bone structures was also performed, and the computed results were compared with those obtained experimentally. Three types of internal fixation plates--one "rigid" control plate and two less rigid experimental plates--were examined using both the finite element and experimental models. These plates were further examined by finite element modeling of a plated human femur during single stance loading. In all cases, the "rigid" control plate was found to shield the underlying bone from stress, while both experimental plates were found to have significantly less bone stress shielding. Our findings suggest that an improved plate design should have a low axial stiffness but moderate bending and torsional stiffnesses to facilitate fracture healing and bone remodeling without causing osteopenia.
Animals↗