Search PubMed⌕ Search

Biomedical subjects

C R Bird

Publications and source records attributed to C R Bird.

67 records · Page 4Linked to original sources
PubMed1984

Immunoblotting with monoclonal antibodies: loss of immunoreactivity with human immunoglobulins arises from polypeptide chain separation.

Immunoblotting has been used to study the antigen binding characteristics of 5 monoclonal antibodies (Mc/Abs) against human Ig (1 anti-kappa, 2 anti-gamma and 2 anti-delta chain. Of the 4 Mc/Abs only 1 (the anti-kappa chain Mc/Ab) reacted with its antigen when blotted from reducing SDS polyacrylamide gels. However, the 4 Mc/Abs which recognise immunoglobulin heavy chains were able to bind their antigens when blotted from native or non-reducing SDS gels. The lack of reactivity of the latter Mc/Abs in blots from reduced SDS gels may be attributed to the separation of Ig which occurs during electrophoresis after the -S-S- bonds are broken. It may be concluded that the conformation of Ig heavy chains is considerably altered when Ig molecules are disrupted and Ig chains separated, and several heavy chain determinants are lost during this process. Therefore determinants recognised by the anti-heavy chain Mc/Abs are most likely to be of the 'conformational' type whereas the anti-light chain Mc/Ab may well recognise a purely sequential determinant.

Antibodies, Anti-Idiotypic↗
PubMed1981

Fibromuscular dysplasia of the internal carotid artery: percutaneous transluminal angioplasty.

Percutaneous transluminal angioplasty was used to successfully dilate critical narrowings of the internal carotid artery caused by fibromuscular dysplasia. The technique of this new procedure is presented along with the angiographic findings and results in three patients. Angioplasty may be used as an alternative to open arteriotomy and graduated dilatation in treating stenosis due to symptomatic fibromuscular dysplasia in the immediate extracranial part of the internal carotid artery.

Aged↗
PubMed1980

Nonspecific ulcers of the colon resembling annular carcinoma: subject review.

Diagnosis of nonspecific ulcers of the colon is extremely difficult before surgery. They may present as an acute abdominal emergency or have a more insidious onset and course. They are commonly found in the cecum, where they frequently perforate. The various symptoms associated with the disease, as well as its appearance on barium enema examination, are discussed. Four cases are described in which nonspecific ulcers of the colon resemble annular carcinoma.

Adult↗
PubMedDate not supplied

MR characteristics of meningioma subtypes at 1.5 tesla.

Analysis of MR signal characteristics and histopathologic findings confirms the strong correlation between meningioma subtype and observed signal intensity (SI) changes in 24 patients imaged at 1.5 T. On T2-weighted images, 90% of fibroblastic and transitional tumors were hypointense relative to cerebral cortex (SI intermediate greater than SI T2-weighted images); conversely, 66% of meningothelial subtypes displayed persistent hyperintensity (SI intermediate less than or equal to SI T2-weighted images), and the remaining one-third demonstrated mixed high-signal changes. Subtype specific differences in collagen distribution and cellularity, i.e., tumor geometry, appeared to account for these signal trends. Based solely on SI characteristics, correct histologic subgrouping of tumors as either fibroblastic/transitional or meningothelial/angioblastic was possible in 80% (19 of 24) of patients. Utilization of adjunctive imaging features (i.e., mass effect, peritumoral edema, intratumoral cyst formation) in conjunction with signal changes permitted a correct histologic pattern in 96% (23 of 24) of patients.

Adult↗
PubMedDate not supplied

Pathophysiology of "reverse" edema in global cerebral ischemia.

A small percentage of patients who suffer a global cerebral hypoxic/ischemic event develop reversal of the normal density relationships of gray and white matter on CT. CT and pathologic findings in the three cases presented indicate that this phenomenon appears to result from distension of deep medullary veins secondary to partial obstruction of venous outflow from elevated intracranial pressure. The "reverse" edema sign indicates a severe hypoxic/ischemic injury to the brain and has a poor clinical prognosis.

Brain Diseases↗
PubMedDate not supplied

MR assessment of myelination in infants and children: usefulness of marker sites.

A retrospective study was made of 60 patients, 1 month to 3 years old, to determine the normal progression of white matter myelination on MR imaging. All examinations were performed with a 1.5-T unit, and axial T1- and T2-weighted images were evaluated in each patient. Multiple sites in the cerebral hemisphere and cerebellum were examined in each case for the presence and degree of myelination. The results show that MR imaging is sensitive to the early changes of white matter myelination, and imaging patterns correlate with known patterns from pathologic studies. At the time of birth in a full-term infant the posterior limb of the internal capsule, central corona radiata, and cerebellar peduncles show visible myelination. Myelination in the centrum semiovale then proceeds anteriorly and posteriorly. Both T1- and T2-weighted images show these changes, which are best explained by a decrease in the water content of white matter as myelination progresses. Knowledge of these normal myelination patterns is essential in evaluating MR imaging studies in infants and children and in diagnosing delayed myelination.

Aging↗
PubMedDate not supplied

Type I schizencephaly: CT and neuropathologic findings.

Type I schizencephaly, which is less commonly recognized than the type II variety, consists of a "fused" cleft in the cerebral mantle. Its CT appearance is significantly different from the type II variety, and it may be confused with postdevelopmentally acquired lesions. The CT appearance of eight cases (seven girls and one boy, aged 10 months to 18 years) of type I schizencephaly was correlated with clinical findings and previously recorded neuropathologic features. Presenting symptoms included developmental delay, seizures, and hemiparesis. CT findings in each case showed a unilateral, cortically lined cleft in the parasylvian region extending from the hemispheric surface to the ventricle. Micropolygyria was present in the cortex lining the cleft, and in two of eight patients was also visible elsewhere in the cerebral cortex. Those with associated microcephaly (four of eight patients) had significantly more severe neurologic deficits than did those without microcephaly. CT findings in type I schizencephaly are characteristic and show excellent correlation with neuropathologic specimens. The appearance of these lesions can be explained on the basis of a disorder of neuronal migration in early gestation and they should not be confused with postdevelopmentally acquired lesions.

Adolescent↗
PubMedDate not supplied

CT anatomy of the craniovertebral junction in infants and children.

Computed tomographic (GE 9800) images of 129 patients (from newborn to 18 years old) with no evidence of cervical spine pathology were reviewed retrospectively from available material to evaluate normal anatomic appearances in childhood. The synchondroses may appear solid at soft-tissue window settings, while, with appropriate bone-window settings, a lucent line will be seen. Residual lucency and then (generally) sclerosis were seen at synchondroses past the age of classic anatomic fusion. A transversely oriented groove on the undersurfaces of the occipital condyles was imaged in children ages 5-12 years. This groove is described radiologically in that age range for the first time in this report. The development of the ossification centers of C1 was illustrated with CT. The two vertically oriented, rod-shaped ossification centers of the lower dens develop a bilobed appearance in axial section when they begin to fuse. An apparent deficiency of the cortex seen posteriorly in this area (in children as old as 7 years) represents the last remnant of the cleft between the dens centers. The cord was always outlined distinctly by CSF at soft-tissue settings at the foramen magnum and C1 levels without intrathecal or IV contrast enhancement. This anatomic feature is particularly useful since it enables the evaluation of the spinal canal in this region in some cases (especially craniovertebral junction anomalies) without the need for intrathecal contrast materials.

Adolescent↗
PubMedDate not supplied

Left-right temporal region asymmetry in infants and children.

Thirty-two consecutive cranial computed tomographic (CT) scans in normal infants ranging from 1 day to 3 years of age were evaluated for asymmetry of the temporal lobes as evidenced by differences in the size of the sylvian fissures. The left sylvian fissure was larger than the right in 23 of the 32 cases, which was statistically significant (p less than 0.0001). In five other cases the two sides were equal; in the four remaining cases, the right side was larger than the left. The results show that asymmetry of the temporal lobes can be demonstrated in vivo even at birth and that this asymmetry is a normal developmental difference between the two hemispheres and not secondary to an acquired abnormality.

Cerebral Aqueduct↗
PubMedDate not supplied

Safety of contrast media in cerebral angiography: iopamidol vs. methylglucamine iothalamate.

A randomized double-blind study was performed in 27 patients to compare the clinical safety, incidence of pain and warmth, and film quality produced by iopamidol and Conray-60 in selective cerebral angiography. No complications or adverse reactions occurred in either group. Iopamidol was significantly less painful than was methylglucamine iothalamate for common carotid artery injections and caused significantly less heat in both common carotid and internal carotid artery injections. Film quality and diagnostic accuracy were excellent in both groups. These results, when viewed in conjunction with laboratory data demonstrating the decreased neurotoxicity of nonionic contrast agents, suggest that iopamidol is an important advance in the development of angiographic contrast media.

Adult↗