Solid state phosphorus-31 magnetic resonance imaging of bone mineral

Chemically selective solid state phosphorus-31 nuclear magnetic resonance (NMR) imaging of the mineral phase of bone and synthetic calcium phosphate models for bone mineral is demonstrated with microscopy-scale (about 5 mm field of view) apparatus at 6.0 T magnetic field strength. Pixel-by-pixel linear combination of image data from multiple radio frequency (RF) pulse sequences, chosen to develop contrast between chemical constituents of interest in the mineral, generates derived images showing the distribution of individual constituents. The technique combines the noninvasive character of magnetic resonance imaging (MRI) with the ability of solid state NMR spectroscopy to characterize subtle chemical variations in bone mineral, as well as to measure the amount of mineral. These methods are, in principle, extensible to larger dimensional scales suitable for live animal subjects or human limbs.

Elderly residents: perceptions of nurses' comforting touch

1. Elderly nursing home residents often feel unwanted or unloved because of a lack of physical contact with others or their caregivers' inability to communicate love and belonging. 2. In a study of 25 elderly nursing home residents, it was found that those who were subjected to comforting touch by their nurses perceived an increased feeling of affection and immediacy. 3. The conscious and intentional use of comforting touch by nurses and caregivers to elderly nursing home residents should be encouraged because of its beneficial effect of conveying love and belonging.

Steps in the evolution of extracranial time-of-flight MR angiography

Magnetic resonance (MR) angiography is not a set technique but is constantly evolving. This article illustrates changes in image quality in extracranial MR angiography that have been achieved over the past few years by the introduction of several technical developments. Images from patients examined at intervals of 12 months or more demonstrate the improvements in image quality that have resulted from these technical changes. These include bandwidth optimization for operation at 1.0 T and changes in flip angle section thickness, repetition time, and echo time. Improved image quality was assessed with objective measures of contrast-to-noise and signal-to-noise ratios. The cases illustrated show the use of MR angiography to evaluate the portal or systemic veins in patients being evaluated for liver transplantation, venous occlusion, and other venous disease. Improvements in image quality are subjectively apparent and emphasize the importance of keeping pace with technical improvements in MR angiography.

Antioxidant status of dairy cows supplemented prepartum with vitamin E and selenium

Possible relationships among dietary antioxidants, oxidative status, and placental retention were investigated in periparturient dairy cows. During 6 wk prepartum, 16 cows each were given daily by capsule 1000 IU of vitamin E, 3 mg of Se, both vitamin E and Se, or neither (control). alpha-Tocopherol in serum and fast-acting antioxidants in plasma increased, but, in red blood cells, thiobarbituric acid-reactive substances decreased during the last 6 wk before parturition in cows given vitamin E. These measurements were unaffected by supplementation of Se. Cows that had retained placenta > or = 12 h had lower fast-acting antioxidants in plasma and glutathione peroxidase in red blood cells up to 2 wk before calving than did cows that shed fetal membranes in < 12 h. Results suggest that inadequate dietary antioxidants may increase oxidative stress, production of lipid peroxides, and incidence of retained fetal membranes in dairy cows.

Hypertension secondary to chlorpropamide with amelioration by changing to insulin

A retrospective analysis of the records of 22 type II diabetics whose treatment had been changed from insulin to chlorpropamide was performed to investigate the relative effects of insulin and chlorpropamide on blood pressure. Although diastolic BP index was not significantly different between the treatments, systolic BP index was significantly higher on chlorpropamide than on insulin (141 +/- 3 v 135 +/- 3 mm Hg, P = .02). In 10 patients in whom insulin was reinstituted, systolic BP fell significantly (P < .005), suggesting that in type II diabetics chlorpropamide exerts a relative hypertensive effect in comparison to insulin.

Measurement of visceral blood flow with magnetic resonance imaging

With the increasing application of magnetic resonance imaging (MRI) and MR angiography in parenchymal liver disease, methods are becoming more widely available for noninvasive measurement of visceral blood flow. Amplitude-based (time-of-flight) and phase-based techniques have proved effective for measurement of portal blood flow, and phase-sensitive methods are applicable to arterial flow measurements. Because respiratory motion degrades the quality of examinations in the abdomen, it is desirable to use methods that can generate flow information in a breath-hold period. Although substantial technical difficulties persist for quantitative arterial flow measurements in the abdomen, the technical requirements for venous flow are less stringent, and important clinical information can be derived using straightforward techniques. The authors describe the principles of flow measurement using time-of-flight and phase methods in visceral arteries and veins, and discuss their practical implementation. Clinical applications are discussed, based on the experience of the authors and others working in the field.

The transverse carpal ligament. An important component of the digital flexor pulley system

The effect of release of the transverse carpal ligament on the mechanics of the flexor tendons was investigated with use of a fresh-frozen cadaver model. A 25 per cent increase in the amount of excursion of the tendons that was consumed by motion of the wrist was demonstrated for the digitorum profundus tendons after transection of the transverse carpal ligament, and a 20 per cent increase was noted for the digitorum superficialis tendons (p < 0.001). These values represent 5.4 +/- 1.2 and 5.5 +/- 1.3 millimeters of bow-stringing for each group of tendons.

Real-time NMR beam-directed velocity mapping. V-mode NMR

BACKGROUND

Currently available noninvasive techniques for measuring blood flow velocities are constrained by limited view orientations (Doppler ultrasound) or limited time resolution (magnetic resonance imaging, MRI). We describe an MRI technique for measuring flow velocities in real time at arbitrary orientations within a cylindrical volume or "beam": V-mode nuclear magnetic resonance (NMR).

METHODS AND RESULTS

The technique was implemented on a standard 1.5-T clinical NMR imager with no special hardware and was tested on phantoms and human volunteers. The beam can be fired at rates up to 60 times per second, allowing measurements on a time scale that is appropriate for ungated cardiac studies. In phantoms, steady flow velocities were measured with the beam aligned along the direction of flow, and the measured velocities correlated well with the actual velocities (r > 0.99). The radial distribution of velocities in phantoms under constant flow conditions was also determined. In humans, flow of blood in the descending aortas of normal and aortic insufficiency subjects was measured. Distinctive backflow of blood because of aortic insufficiency was readily apparent.

CONCLUSIONS

The V-mode NMR technique is capable of acquiring clinically relevant real-time blood flow information from any desired angle of view with no attenuation at bone or air-tissue interfaces.

Neonatal compartment syndrome

Two cases of forearm compartment syndrome in neonates are presented. The compartment syndrome may be initiated before actual delivery and may appear in an advanced stage. In both children good clinical results were achieved when standard guidelines for managing compartment syndrome and established Volkmann's contracture were applied. Although uncommon, compartment syndrome should be considered in the differential diagnosis of the neonate who is unable to move an extremity.

Rapid NMR cardiography with a half-echo M-mode method

A real-time NMR cardiac profiling pulse sequence has been developed that incorporates two-dimensional (2D) selective excitation and a half-echo readout. The time resolution has been improved by a factor of two relative to the previous flow-compensated, full-echo version. The technique produces a 2D plot of "beam"-axis position versus time, analogous to M-mode echocardiography. In human subjects, details of valve leaflet motion, intracardiac flow, wall motion, and wall thickening may be observed along optimal lines of sight selected interactively. The pulse sequence uses a low-tip-angle 2D selective-excitation pulse derived from a spiral k-space trajectory to excite a narrow cylinder of magnetization, followed by a half-echo readout gradient oriented along the axis of the cylinder. One-dimensional Fourier transformation of the acquired signal results in a magnetization profile along the length of the cylinder, or beam. The pulse sequence is effectively flow compensated without any additional gradient lobes, because the rapid oscillation in the gradient wave forms of the 2D excitation pulse produces relatively small net gradient moments, and the shortened readout gradient has minimal first-order moment relative to center echo. The signal from moving blood can alternatively be velocity encoded by the addition of bipolar gradients along any of the three axes, producing Doppler-like traces of intracardiac blood flow.

Radial shortening for Kienböck disease

The cases of twenty-nine consecutive patients (thirty wrists) who had radial shortening for the treatment of stages I through IIIB Kienböck disease were reviewed to assess the results of this procedure. Thirteen patients (45 per cent) had a history of trauma, and all thirty wrists had a negative ulnar variance (average, 2.8 millimeters) on radiographs. All wrists were re-examined after an average follow-up of 3.8 years (minimum, two years). At that time, the pain had decreased in 87 per cent of the wrists. Extension of the wrist had improved an average of 32 per cent; flexion, 27 per cent; radial deviation, 30 per cent; ulnar deviation, 41 per cent; and grip strength on the affected side, 49 per cent. Analysis of the radiographs by computer digitization showed no significant changes in the amount of collapse of the lunate at the latest follow-up. In two wrists, there were complications at follow-up (excessive shortening of the radius and non-union of the radial osteotomy). Radial shortening is an effective treatment for Kienböck disease in wrists that do not have degenerative changes in adjacent carpal joints. Pain, range of motion, and strength can be expected to improve, but the radiographic appearance of the lunate changes little, if any.

Progress in efforts to prevent the spread of HIV infection among youth

The Human Immunodeficiency Virus (HIV) that causes AIDS will continue to threaten public health for years to come. Despite some popular misperceptions, adolescents are at risk of infection. Twenty percent of persons reported with AIDS have been ages 20 through 29. Given the long incubation period between HIV infection and AIDS, some of these young adults probably were infected while they were teenagers. Young people must develop the skills they will need to avoid HIV infection and other related health problems. In 1987, the Centers for Disease Control (CDC) launched a national program to help schools and other agencies that serve youth across the nation provide effective health education to prevent the spread of HIV. CDC supports and works closely with national health and education organizations, State and local education agencies, colleges and universities, and local health departments to establish HIV prevention policies and programs, training and demonstration centers, information development and dissemination activities. The impact of these efforts are assessed through applied surveillance and evaluation research. Through this system, CDC is attempting to institutionalize the means for continuously providing educational programs that will be effective in preventing HIV infection and other important health problems.

Unconstrained shoulder arthroplasty. A five-year average follow-up study

A series of 42 total shoulder arthroplasties and four humeral hemiarthroplasties were performed with either the English-McNab or Neer prosthesis. Retrospective follow-up study averaged five years with a three-year minimum. Preoperative diagnoses included rheumatoid arthritis, osteoarthritis, posttraumatic arthritis, rotator cuff arthropathy, avascular necrosis, failed prosthesis, and congenital dislocation. Postoperatively, pain improved in 94% of shoulders, and active range of motion improved an average of 42 degrees in abduction and 47 degrees in forward flexion. Rotator cuff lesions were correlated with poorer postoperative function. Complications developed in four shoulders (9%) and consisted of humeral component protrusions (two shoulders), loosened prosthesis (one shoulder), and unrecognized, preoperative tuberculous infection (one shoulder). Fifteen glenoid components (36%) and six humeral components (13%) developed lucent lines roentgenographically, but only one glenoid component developed migration.

Vascularized fibular grafts in the treatment of congenital pseudarthrosis of the tibia

Free vascularized fibular bone grafts were used in nineteen children, seen consecutively, who had congenital pseudarthrosis of the tibia. The average age was 5.1 years (range, 1.4 to 11.4 years). Sixteen of the patients had been treated with electrical stimulation for at least one year, and the tibia had not united. All but four patients had had at least one previous operative procedure. At an average follow-up of 6.3 years (range, 2.0 to 11.0 years), eighteen (95 per cent) of the nineteen pseudarthroses had healed. The leg-length discrepancy averaged 1.6 centimeters (range, 0 to 4.0 centimeters), but ten tibiae had residual or progressive valgus or anteroposterior malalignment despite bracing. There was minimum morbidity at the donor site.

Glomus tumor originating within a digital nerve

Glomus tumors are thought to arise from specialized cells normally found within the glomus apparatus of the dermal stratum reticularis. We report the unusual occurrence of a glomus tumor from within a peripheral nerve. Previous investigators have suggested that the rare occurrence of glomus tumors in tissue where the glomus apparatus has not been described arise from ectopic glomus cells or differentiate from nonglomus cell sources. Many of the "ectopic" glomus tumors have been found in regions of extensive arteriovenous shunting such as in the digestive system and lung suggesting the presence of glomera at these locations. The finding of a glomus tumor within a peripheral nerve, a region where extensive arteriovenous shunting and glomus bodies have not been described, supports the occasional origin of a glomus tumor from a nonglomus cell source.

Oxygen radical scavengers improve vascular patency and bone-muscle cell survival in an ischemic extremity replant model

We examined the use of oxygen radical scavengers in preventing the no-reflow phenomenon and improving bone-muscle cell survival in an ischemic extremity replant model. A total of 70 Lewis rat modified hindlimb replants were performed after specific periods of cold ischemia and intraarterial perfusion with either superoxide dismutase and catalase, specific oxygen free-radical scavengers, or a control solution. Ischemic hindlimbs treated with superoxide dismutase and catalase showed a statistically significant (p less than 0.05) improvement in vascular patency after prolonged cold ischemia when compared to controls. Histologically, experimental extremities demonstrated greater osteoblast, osteocyte, and muscle cell survival in replanted hindlimbs with patent vascular anastomoses. The perfusion of severed limbs and digits and free vascularized tissue transfers with superoxide dismutase and catalase after a period of ischemia has already occurred may prolong the ischemic "time window" tolerated for successful tissue survival.

Natural alteration of speaking rate: the effect on passage comprehension by listeners over 75 years of age

The purpose of the study was to assess the comprehension performance of "old-old" listeners for naturally rate-altered passages. Fourteen men and 14 women between 75 and 84 years of age responded to comprehension questions after hearing matched passages at four different rates. The listeners' performances were significantly worse under 60% time compression than at normal rate and two rates of time expansion. Comprehension differences between the sexes were not significant. The results are compared with prior findings for old-old listeners responding to electronically altered speech stimuli (Schmitt, 1983a) and for "young-old" listeners (65-74 years of age) who also responded to naturally rate-altered passages.

Nursing home employee attitudes towards AIDS

This article examines nursing home employee attitudes toward issues related to AIDS and is based on data collected from 343 employees from 13 nursing homes in rural, small towns in sourthern Illinois during the spring of 1988. Results suggested that a large majority of the employees had negative attitudes toward people with AIDS. For example, 67% of the sample indicated that it was more important to limit the spread of AIDS rather than to protect the rights of people with AIDS. Furthermore, 42% suggested that AIDS patients should be sent to sanitariums to protect others from AIDS. Greater than half of the sample (56%) responded that they would feel uncomfortable around people with AIDS. About one third (32%) felt that being around someone with AIDS would put their health in danger, and 21% would be afraid to even take care of a family member with AIDS. With regard to job-specific AIDS attitudes, 51% indicated that health-care workers should be able to refuse to work with AIDS patients, and another 46% felt that hospitals and nursing homes should be able to refuse to admit people with AIDS. In addition to these and other results, this article presents a brief discussion concerning possible educational strategies which might be implemented in this setting to reduce the negative attitudes of these employees. Considerations are also presented for nursing home administrators, who face the problem of developing effective policies for dealing with the rising number of AIDS patients who will be admitted to their facilities.

Capitellocondylar total elbow replacement. A long-term follow-up study

The results of forty total elbow replacements in which a capitellocondylar prosthesis was implanted in thirty-five patients (five of whom had a bilateral procedure) were reviewed retrospectively. The average length of follow-up was 7.2 years (range, four to twelve years). Pronation, supination, and flexion of the elbow improved considerably, but extension did not change a great deal. The average rating of the elbow, according to the scoring system of Ewald et al., improved from 30 to 88 points, but the functional score, as defined by the American Rheumatism Association, improved in only four patients. Malarticulation or dislocation of the prosthesis occurred in ten patients (29 per cent). In two other patients, a deep infection developed, necessitating removal of the prosthesis. Ten prostheses (ten patients) had radiolucent lines on follow-up radiographs, but these lines were not associated with pain or loosening. Seven patients (seven elbows) had a transient ulnar-nerve palsy. The incidence of this complication was reduced from 30 per cent (five of seventeen patients) to 15 per cent (four of twenty-eight patients) when the lateral Kocher approach to the elbow was adopted.