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Biomedical subjects

C Cook

Publications and source records attributed to C Cook.

99 records · Page 6Linked to original sources

Ocular teratology.

The principles of teratology are described, and animal models for research in abnormal ocular development and clinical studies of human teratogens are surveyed. A review is made of presumed ocular teratogenic agents: radiation; external environmental teratogens; maternal conditions such as infections, diabetes, and epilepsy; alcohol and drugs such as thalidomide, retinoic acid, and coumarin anticoagulants; and other agents, such as cigarettes.

Abnormalities, Drug-Induced↗

Effects of vasoactive intestinal peptide on human sperm motility.

Sperm flagellar activity is modulated by cAMP. In target tissues, vasoactive intestinal peptide (VIP) stimulates adenyl cyclase activity, which elevates intracellular cAMP levels and activates protein kinase activity. This study investigated the effects of VIP on motility of sperm from 17 subjects. Motile activities, monitored before (0 min, baseline) and for 40 min after incubation with VIP (0.2 microgram/mL cell suspension), were analyzed by computer-assisted semen analysis. The data (mean +/- SEM) are expressed as percentages of baseline values and changes were compared by trend analysis for interval level measures by repeated measures analysis of variance orthogonal polynominal contrasts. The addition of VIP significantly increased motile sperm concentration (110 +/- 17% [10 min], 132 +/- 15% [20 min], 152 +/- 18% [30 min], 125 +/- 18% [40 min]; p < .02) and sperm with rapid straight-line motility (V > 25 microns/s) (167 +/- 20%, 174 +/- 19%, 173 +/- 23%, 141 +/- 16%; p < .02). Mean track speed (micron/s) was increased (125 +/- 12%, 134 = 9%, 129 +/- 12% and 126 +/- 12%; p < .02), while mean progressive velocity, amplitude of head displacement, and beat frequency were not affected by VIP. These results indicate that VIP stimulates sperm motile activity by cAMP-mediated phosphorylation of axonemal proteins.

Adenylyl Cyclases↗

Lower extremity neuromuscular recovery following anterior cruciate ligament reconstruction; a 2-week case study.

The lower extremity neuromuscular recovery of a 31-year-old male physical therapy student during the initial 2-weeks following anterior cruciate ligament reconstruction was evaluated by measuring involved side vastus medialis (VM), gluteus maximus (GMAX) and gastrocnemius (GASTROC) electromyographic (EMG) signals (1000 Hz), plantar forces (50 Hz), and knee pain as the subject performed a series of volitional, maximal effort unilateral, isometric leg presses (6 sec) in a modified continuous passive motion device. Data were standardized to pre-operative values and graphically plotted for split middle technique, celeration line assessment. From 1-8 hours post-surgery, EMG amplitudes and plantar forces decreased, pain increased, and plantar force location shifted toward the forefoot. From 9-12 hours post-surgery, EMG amplitudes and plantar forces increased and pain decreased. By 24 hours post-surgery, pain decreased to pre-operative levels. From 24-72 hours post-surgery, EMG amplitudes and plantar forces increased. From 1-2 weeks post-surgery, EMG amplitudes and plantar forces increased. From 9 hours-2 weeks post-surgery, plantar force location shifted toward the pre-operative location. Sequential increases were observed for GMAX, GASTROC, and VM EMG amplitudes. By 2 weeks post-surgery, plantar forces and VM EMG amplitudes remained reduced. Reduced plantar forces and VM EMG amplitude at 2 weeks post-surgery suggest a need for greater focus on restoring VM function before attempting closed kinetic chain exercises that require the full shock absorption capabilities of the quadriceps femoris muscle group.

Adult↗

MR imaging volumetry of subcortical structures and cerebellar hemispheres in temporal lobe epilepsy.

BACKGROUND AND PURPOSE: There is mounting evidence of extratemporal volume changes associated with medically refractory temporal lobe epilepsy (TLE). This MR imaging study aimed to characterize volume changes in subcortical structures and cerebellar hemispheres with respect to lateralization of the seizure focus, onset and duration of epilepsy, and frequency of generalized tonic-clonic seizures (GTCS). METHODS: Amygdalar, hippocampal, thalamic, caudate head, and cerebellar volume measurements were obtained in the preoperative MR images of 40 patients with TLE (20 right, 20 left), who underwent temporal lobe resection with good outcome, and in 20 right-handed control participants. All 3D MR images were spatially aligned and normalized before measurements were obtained. Standardized volumes and right-to-left volume ratios (VRs) were compared between control participants and right and left TLE groups. Multiple regression analyses were performed to study the effects of epilepsy onset and duration and GTCS frequency on ipsilateral-to-contralateral VRs with respect to the resected seizure focus. RESULTS: Thalamic volumes were smaller bilaterally in patients with TLE. Hippocampal volumes were smaller ipsilateral to the seizure focus, but there was no significant volume loss involving the amygdala, caudate, or cerebellum. Hippocampal and amygdalar right-to-left VRs differed significantly between right and left TLE groups and controls, whereas thalamic right-to-left VRs differed only between the TLE groups. Thalamic ipsilateral-to-contralateral VRs were correlated positively with epilepsy onset and negatively with epilepsy duration. Caudate ipsilateral-to-contralateral VRs were positively, whereas amygdalar and cerebellar VRs were negatively, correlated with GTCS frequency. CONCLUSIONS: Unilateral amygdalar and bilateral thalamic volume loss, in the absence of caudate head atrophy, is likely to reflect seizure-induced injury due to TLE. Correlations of VRs affecting the amygdala, caudate, and cerebellum with GTCS frequency may also reflect injury or a prediposition for secondary generalization. Potential effects of complex partial seizures, febrile seizures, or antiepileptic medications on subcortical structures need to be evaluated in future studies.

Cerebellum↗