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Biomedical subjects

J H Harris

Publications and source records attributed to J H Harris.

At least 19 recordsLinked to original sources
PubMed1998

Is cervical spine imaging indicated in gunshot wounds to the cranium?

BACKGROUND, MATERIALS AND METHODS: Because there is no consensus regarding the necessity of imaging the cervical spine of patients who sustain a gunshot wound to the cranium, the cervical spinal radiographs of 53 consecutive patients with gunshot wounds to the cranium admitted to Hermann Hospital, a Level I trauma center, from January of 1993 to January of 1996, were reviewed. RESULTS: The cervical spine radiographs of all 53 patients were negative. CONCLUSIONS: Cervical spine injury is not associated with gunshot wound to the cranium. Therefore, patient management decisions/procedures, including endotracheal intubation, should not be delayed pending cervical spine imaging.

Cervical Vertebrae↗
PubMed1997

Use of inpatient hospital services by people aged 90-99 years.

OBJECTIVE: To examine the use of inpatient hospital services by people aged 90-99 years. DESIGN: Retrospective case note review. SETTING: Flinders Medical Centre, a 516-bed university teaching hospital in Adelaide, South Australia. PATIENTS: All patients aged 90-99 years on the separation register for 1995. MAIN OUTCOME MEASURES: Patient demographic characteristics, principal diagnosis, length of hospital stay and outcome, including destination at discharge. RESULTS: In 1995, 317 separations involved 214 patients aged 90-99 years; 148 patients (69%) were admitted to hospital once, 43 (20%) twice and 23 (11%) three times or more. In 54% of separations, patients came from the community, and these were less likely to be emergency admissions (72%) than were admissions from hostels (87%) and nursing homes (93%). Patients had a wide range of acute medical and surgical problems and a median of five documented comorbidities. Patients survived to leave hospital in 290 separations (91%) and returned directly to their previous living circumstances in 212 (67%). Median hospital stay was 5.0 days, and in 25% of separations stay was one day or less. Patients admitted under the care of geriatricians had more emergency admissions (98%) and longer mean hospital stays (8.9 days) than those admitted under surgeons (69%; 5.9 days) or other physicians (66%; 5.0 days). CONCLUSION: Despite the acute nature of their illnesses and their multiple medical problems, most hospitalised nonagenarians in this study returned directly to their previous living circumstances after short hospital stays.

Aged↗
PubMed1997

C2-3 facet joint "pseudo-fusion": anatomic basis of a normal variant.

OBJECTIVE: To identify the anatomic basis for apparent C2-3 facet joint fusion (pseudo-fusion) on lateral cervical spine radiographs. DESIGN AND PATIENTS: The studies of 81 consecutive blunt trauma patients who had both plain radiographs and a CT scan of the upper cervical spine were reviewed. The C2-3 facet joints were evaluated on lateral cervical spine radiographs and graded "normal" (category 1), "indistinct" (category 2), or "fused" (category 3), relative to the C3-4 level. The accompanying CT scans were reviewed for the presence of fusion and the angle of orientation of the facet joints relative to the axial and coronal planes. RESULTS: In category 1 ("normal"), the C2-3 facet joints were oriented nearly parallel to the true coronal and axial plane. In category 2 ("indistinct"), both the C2-3 facet joints were oriented obliquely to the true coronal and axial planes. In category 3 ("fused"), the C2-3 facet joints were also oriented obliquely, but at a steeper angle than in category 2. Head tilt/rotation caused a change in category rating in 5 of 81 cases (6.2%). CONCLUSION: The appearance of C2-3 facet joint fusion (pseudo-fusion) on lateral cervical spine radiographs may be a normal anatomic variant. This "pseudo-fusion" is due to the oblique orientation of these facet joints relative to the X-ray beam and is usually unaffected by patient position.

Cervical Vertebrae↗
PubMed1997

Noncorrelation between thoracic skeletal injuries and acute traumatic aortic tear.

It is generally accepted that the presence of thoracic skeletal injuries has a predictive value for acute traumatic aortic tear (ATAT). The purpose of this study is to objectively assess the validity of that premise. The initial chest radiographs of 548 patients who underwent aortic angiography for suspected ATAT were reviewed for thoracic skeletal injuries. The incidence of thoracic skeletal injuries was compared between patients with and without angiographically confirmed ATAT. Rib fracture is the only thoracic skeletal injury whose incidence is statistically significantly higher in patients with ATAT (36 of 62, 58.1%) than in those without (207 of 486, 42.6%) (p = 0.0209). The positive predictive value of rib fractures in evaluating ATAT, however, is 14.8%, a rate similar to the incidence of ATAT at most trauma centers, and the specificity is 57.4%. The second most common finding in patients with ATAT, the absence of thoracic skeletal injury, is not statistically significantly different between patients with ATAT (24 of 62, 38.7%) and those without (220 of 486, 45.3%) (p = 0.3279). We conclude that (1) there is no clinically relevant correlation between thoracic skeletal injuries and ATAT, and (2) selection of patients requiring thoracic aortography must be based on appropriate mechanism of injury and radiographic evidence of mediastinal hematoma.

Aneurysm, False↗
PubMed1994

Effects of branching and molecular weight of surface-bound poly(ethylene oxide) on protein rejection.

To understand better the origin of protein rejection observed with surface-bound poly(ethylene oxide) (or PEO), we have measured fibrinogen adsorption for a series of linear and branched, low-molecular-weight PEOs bound to solid polystyrene surfaces. The results show that a dependence on molecular weight is found below 1500 g mol-1 for linear PEO. Branched PEOs are less effective at protein rejection than linear PEOs. The branched PEOs have smaller exclusion volumes (from GPC) than the corresponding linear PEOs, consistent with restriction in conformational freedom for the branched compounds. The protein rejection results are interpreted in terms of entropy changes that result upon protein adsorption. In addition, some practical problems in preparation of PEO glycidyl ethers have been clarified, thus making these PEO derivatives more useful for surface modification.

Adsorption↗
PubMed1994

Radiologic diagnosis of traumatic occipitovertebral dissociation: 1. Normal occipitovertebral relationships on lateral radiographs of supine subjects.

OBJECTIVE: The objective of this study was to establish a reliable method of determining the normal occipitovertebral relationship seen on lateral radiographs of the cervical spine in supine subjects in order to recognize alterations of normal that characterize occipitovertebral dissociation. MATERIALS AND METHODS: We define the rostral extension of the posterior cortex of the axis body as the posterior axial line, the distance between the basion (tip of the clivus) and the posterior axial line as the basion-axial interval, and the distance between the basion and the rostral tip of the dens as the basion-dental interval. The basion-axial interval was measured on horizontal-beam lateral radiographs of the cervical spine obtained at a 40-in. (1-m) target-film distance in 400 adults who had no occipitovertebral abnormalities. The basion-dental interval was measured in 374 (94%) of the same cohort of adults in whom the superior cortex of the dens could be identified. All radiographs were obtained with the subjects supine. The excursion of the basion referable to the posterior axial line was determined on lateral flexion and extension radiographs of 25 of the same cohort of adults. The basion-axial interval only was measured on radiographs of 50 children 2-13 years old who had no occipitovertebral abnormalities. RESULTS: In 392 (98%) of the 400 adults, the basion-axial interval did not exceed 12 mm. In eight adults (2%), the basion was situated 1-4 mm posterior to the posterior axial line. The excursion of the basion in flexion and extension ranged from 0 to 10 mm, but did not exceed the 12-mm limit of normal. The basion translated posterior to the posterior axial line in six (24%) of the 25 adults in whom excursion was measured. Of the 400 adults, the basion-dental interval ranged from 2 to 15 mm (mean, 7.5 +/- 4.3 mm [2 SD]); the 95% accuracy range was 11.8 mm. In all 50 children (100%), the basion was within the normal basion-axial interval of 12 mm, and in no instance was the basion posterior to the posterior axial line. CONCLUSION: In adults, the occipitovertebral junction can be considered normal when both the basion-axial interval and basion-dental interval are 12 mm or less. In children less than 13 years old, the basion-dental interval is not reliable because of the variable age at which complete ossification and fusion of the dens occur. The normal basion-axial interval in children did not exceed 12 mm. This simple, anatomically based method of recognizing normal occipitovertebral relationships facilitates identification of occipitovertebral dissociation.

Adult↗
PubMed1994

Radiologic diagnosis of traumatic occipitovertebral dissociation: 2. Comparison of three methods of detecting occipitovertebral relationships on lateral radiographs of supine subjects.

OBJECTIVE: The purpose of this study was to describe a method for recognizing acute traumatic occipitoatlantal dissociation that uses the basion-axial interval and basion-dental interval and to compare the accuracy of this method with the accuracies of two other methods: the Powers ratio and the x-line method. MATERIALS AND METHODS: Lateral radiographs of the cervical spine of 37 patients in whom the diagnosis of occipitoatlantal dissociation had been made on the basis of the relationship of the basion to the tip of the dens, the Powers ratio, and/or the x-line method were reviewed. Retrospectively, the occipitoatlantal junction of each was reassessed by using the the Powers ratio, the x-line, and the basion-axial interval-basion-dental interval methods. Independently, the neurologic findings at admission and the final neurologic diagnosis at discharge were obtained from the hospital records and were compared with the radiologic findings to determine the degree of radiologic-clinical correlation. RESULTS: Three groups of patients were identified by analyzing the basion-axial and basion-dental intervals of the occipitovertebral junction and related clinical findings. Twenty-three patients (group 1) had frank occipitoatlantal dislocation. Eight patients (group 2) had incomplete occipitoatlantal dissociation, which was defined as occipitoatlantal subluxation. The remaining six patients (group 3) had normal radiologic and clinical findings. Four patterns of occipitovertebral dissociation were identified: purely anterior (4/31, 13%), purely distracted (6/31, 19%), concomitantly anterior and distracted (20/31, 65%), and purely posterior (1/31, 3%). Regardless of the magnitude or direction of occipitoatlantal dissociation, the basion-axial interval-basion-dental interval method correctly identified the abnormality and the type of each. Positive clinical correlation was found in 13 (57%) of the 23 patients in group 1 and in 100% of the eight and six patients in groups 2 and 3, respectively. Neither the Powers ratio nor the x-line method could be applied in 17 (46%) of 37 cases, either because the opisthion could not be detected on the radiographs or because fusion of the posterior arch of C1 had not occurred. In the remaining 20 patients in whom the Powers ratio and the x-line method were applicable, the type of occipitoatlantal dissociation was correctly identified by the Powers ratio in 12 (60%) and by the x-line method in four (20%). Neither the Powers ratio nor the x-line method was applicable in three (50%) of the six patients in whom analysis by the basion-axial interval-basion-dental interval method and clinical findings showed no occipitoatlantal abnormality. Normal occipitovertebral anatomy was correctly identified by the Powers ratio in the remaining three patients (50%) and by the x-line method in two (33%). CONCLUSION: Direct measurement of occipitovertebral skeletal relationships altered by occipitoatlantal dissociation using the basion-axial and basion-dental intervals provides the most accurate radiologic assessment of this injury.

Atlanto-Occipital Joint↗
PubMed1993

Crystallization and preliminary X-ray analysis of the periplasmic dipeptide binding protein from Escherichia coli.

The periplasmic dipeptide-binding protein from Escherichia coli has been purified, freed of bound endogenous ligands, and crystallized. Crystals of the protein in complex with added dipeptides have been subjected to X-ray analysis. The crystals grow as hexagonal bipyramids or eye-shaped disks which have the symmetry of space group P6(1). The unit cell dimensions are a = b = 183 A, c = 212 A, and the diffraction pattern extends to 3.2 A resolution with a conventional X-ray source.

Bacterial Proteins↗
PubMed1992

Hyperextension-dislocation of the cervical spine. Ligament injuries demonstrated by magnetic resonance imaging.

We reviewed the magnetic resonance (MR) images of eight adults with acute hyperextension-dislocation of the cervical spine. The images were obtained to evaluate damage to the spinal cord. All eight patients had disruption of the anterior longitudinal ligament and of the annulus of the intervertebral disc, and separation of the posterior longitudinal ligament from the subjacent vertebra. Some, but not all, showed widening of the disc space, posterior bulging or herniation of the nucleus pulposus, and disruption of the ligamentum flavum. The MR demonstration of these ligament injuries, taken with the clinical and radiographic findings, establishes the mechanism of hyperextension-dislocation, confirms the diagnosis, and is relevant to management.

Cervical Vertebrae↗