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Biomedical subjects

T D McDonald

Publications and source records attributed to T D McDonald.

12 recordsLinked to original sources
PubMed2001

Lung uptake of antibodies to endothelial antigens: key determinants of vascular immunotargeting.

Vascular immunotargeting is a mean for a site-selective delivery of drugs and genes to endothelium. In this study, we compared recognition of pulmonary and systemic vessels in rats by candidate carrier monoclonal antibodies (MAbs) to endothelial antigens platelet endothelial cell adhesion molecule (PECAM)-1 (CD31), intercellular adhesion molecule (ICAM)-1 (CD54), Thy-1.1 (CD90.1), angiotensin-converting enzyme (ACE; CD143), and OX-43. Tissue immunostaining showed that endothelial cells were Thy-1.1 positive in capillaries but negative in large vessels. In the lung, anti-ACE MAb provided a positive staining in 100% capillaries vs. 5-20% capillaries in other organs. Other MAbs did not discriminate between pulmonary and systemic vessels. We determined tissue uptake after infusion of 1 microg of (125)I-labeled MAbs in isolated perfused lungs (IPL) or intravenously in intact rats. Uptake in IPL attained 46% of the injected dose (ID) of anti-Thy-1.1 and 20-25% ID of anti-ACE, anti-ICAM-1, and anti-OX-43 (vs. 0.5% ID of control IgG). However, after systemic injection at this dose, only anti-ACE MAb 9B9 displayed selective pulmonary uptake (16 vs. 1% ID/g in other organs). Anti-OX-43 displayed low pulmonary (0.5% ID/g) but significant splenic and cardiac uptake (7 and 2% ID/g). Anti-Thy-1.1 and anti-ICAM-1 displayed moderate pulmonary (4 and 6% ID/g, respectively) and high splenic and hepatic uptake (e.g., 18% ID/g of anti-Thy-1.1 in spleen). The lung-to-blood ratio was 5, 10, and 15 for anti-Thy-1.1, anti-ACE, and anti-ICAM-1, respectively. PECAM antibodies displayed low pulmonary uptake in perfusion (2% ID) and in vivo (3-4% ID/g). However, conjugation with streptavidin (SA) markedly augmented pulmonary uptake of anti-PECAM in perfusion (10-54% ID, depending on an antibody clone) and in vivo (up to 15% ID/g). Therefore, ACE-, Thy-1.1-, ICAM-1-, and SA-conjugated PECAM MAbs are candidate carriers for pulmonary targeting. ACE MAb offers a high selectivity of pulmonary targeting in vivo, likely because of a high content of ACE-positive capillaries in the lungs.

Animals↗
PubMed1994

Lisfranc's fracture-dislocation. An unusual case presentation.

The authors present a brief review of the literature with an unusual case presentation of Lisfranc's dislocation. The authors review the mechanism of injury, presentation, and treatment alternatives for both acute trauma-related injuries and neuropathic-related injuries to the Lisfranc's joint. The authors discuss the controversy surrounding the preferred treatment of neuropathic-associated injuries and suggest that possibly criteria may be established for fusion versus conservative care of these injuries.

Aged↗
PubMed1993

Persistent and transient "conduction block" in motor neuron diseases.

Although conduction block indicates dysfunction of peripheral nerve, it may occur in patients with clinically typical motor neuron disease. There are no universally accepted criteria to identify conduction block, so diagnosis may be difficult. In some peripheral neuropathies, conduction block persists over long periods of time. If conduction block persists in motor neuron disease, then a more reproducible means for identification would be available. We repeatedly studied 9 patients with different forms of motor neuron diseases; conduction block was suspected because of excessive loss of the amplitude of motor evoked responses between distal and proximal stimulation sites. Five showed persistent amplitude loss at intervals between 12 and 36 months. All had focal loss of amplitude and area across a specific segment; all were men; none had definite upper motor neuron signs, 2 had probable and 3 had no upper motor neuron signs; 1 had IgM paraproteinemia, one elevated anti-GM1 titers; the duration of symptoms spanned 4-13 years. Four patients had transient loss of amplitude that was not reproduced in intervals between 3 and 13 months. None had focal loss of both amplitude and area; 2 were men; all had definite upper motor neuron signs and none had symptoms for more than 3-13 months; and none had immunological abnormalities. Thus, patients with persistent amplitude loss fulfill other criteria for conduction block, have prolonged survival but otherwise have clinical syndromes indistinguishable from ALS, except that definite upper motor neuron signs seem to be exceptional.

Action Potentials↗
PubMed1993

Polyglucosan body disease simulating amyotrophic lateral sclerosis.

We describe two patients with polyglucosan body disease (PBD) with the clinical features of atypical amyotrophic lateral sclerosis (ALS). Patient 1 was demented, and patient 2, of Ashkenazi background, was incontinent of urine. Autopsy of patient 1 revealed diffuse CNS accumulations of polyglucosan bodies (PB) localized primarily in neuronal and astrocytic processes and rarely in neuronal perikarya. PB were present in peripheral nerve and myocardium. Brancher enzyme analysis of nerve and muscle was normal. Patient 2's sural nerve biopsy showed PB. Brancher activity was markedly reduced in nerve but not in leukocytes. Previous reports have shown reduced leukocyte brancher activity in Ashkenazi patients with PBD. Clinically, pathologically, and biochemically, PBD is heterogeneous and may include patients presenting with ALS. Cases in which typical pathologic features of PBD are combined with findings of rare PB in neural perikarya may represent a pathologic variant of PBD. Brancher enzyme activity may be normal or only mildly reduced in leukocytes in Ashkenazi patients with PBD, implying genetic heterogeneity.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1991

Becker muscular dystrophy or spinal muscular atrophy?--Dystrophin studies resolve conflicting results of electromyography and muscle biopsy.

We studied a 29-year-old man with slowly progressive proximal leg weakness, calf hypertrophy, and high serum levels of creatine kinase activity. Clinically, it was not possible to identify his as a sporadic instance of Becker muscular dystrophy (BMD) or one of spinal muscular atrophy. The problem arose because electromyography and elevated creatine kinase suggested a myopathy whereas changes in the muscle biopsy resembled a neurogenic disorder. The diagnosis of BMD was made by DNA analysis which detected a deletion at Xp21 and by immunoelectrophoresis and immunohistochemical tests that identified an abnormal form of gene product, dystrophin. These studies were important for genetic counselling, identifying an X-linked disease instead of one that is autosomal recessive.

Adult↗
PubMed1988

Integration of student development theory into the academic classroom.

This paper demonstrates how collaboration among student development educators and university instructors can utilize the content of academic courses to facilitate personal development in adolescent college students. Through an application of Chickering's (1969) seven vectors of human development (which occur during adolescence and early adulthood), this objective was accomplished in a course entitled Drinking and Driving: Legal and Social Aspects. Essay exams were analyzed for self-reported anecdotal behavioral examples of developmental growth attributable to participation in this course. Analysis of the results indicated that the class content had a definite developmental impact on the students, in addition to intellectual growth. By helping academic educators recognize that within their course content and structure they can and do affect adolescents on many developmental dimensions, the end result can be a richer, holistic educational experience for students.

Adolescent↗