PubMed Health⌕ Search

Biomedical subjects

J L Raymond

Publications and source records attributed to J L Raymond.

At least 19 recordsLinked to original sources

[Influence of feeding method on maxillofacial development].

The functional differences between breast-feeding and bottle-feeding may have a significant effect on dento-facial development and on the genesis of some severe malocclusions. Orthodontists should be aware of this sometimes under-estimated aspect of development. They should, in conformity with their role as professional health care providers, advise long-term breast feeding as a way of preventing certain disorders or, at least, reducing their severity.

Bottle Feeding↗

[Occlusal justification of early treatment of Class III malocclusions].

Authors mostly admit that Class III treatment has more chance of success and stability if it is carried out precociously. Their conviction is primarily based on the use of patient's growth potential. This aspect does not seem to be the main interest of early treatment. The length of the occlusal plane and its impact on mandibular movements (mastication), which can influence growth and maxillomandibular relationships, accounts or even constrains to act as soon as possible. The fundamental objective of early Class III treatment would be the reorientation of the occlusal plane and the rehabilitation of mastication would be the final goal, ensuring an active and physiological result's retention.

Age Factors↗

Neural learning rules for the vestibulo-ocular reflex.

Mechanisms for the induction of motor learning in the vestibulo-ocular reflex (VOR) were evaluated by recording the patterns of neural activity elicited in the cerebellum by a range of stimuli that induce learning. Patterns of climbing-fiber, vestibular, and Purkinje cell simple-spike signals were examined during sinusoidal head movement paired with visual image movement at stimulus frequencies from 0.5 to 10 Hz. A comparison of simple-spike and vestibular signals contained the information required to guide learning only at low stimulus frequencies, and a comparison of climbing-fiber and simple-spike signals contained the information required to guide learning only at high stimulus frequencies. Learning could be guided by comparison of climbing-fiber and vestibular signals at all stimulus frequencies tested, but only if climbing fiber responses were compared with the vestibular signals present 100 msec earlier. Computational analysis demonstrated that this conclusion is valid even if there is a broad range of vestibular signals at the site of plasticity. Simulations also indicated that the comparison of vestibular and climbing-fiber signals across the 100 msec delay must be implemented by a subcellular "eligibility" trace rather than by neural circuits that delay the vestibular inputs to the site of plasticity. The results suggest two alternative accounts of learning in the VOR. Either there are multiple mechanisms of learning that use different combinations of neural signals to drive plasticity, or there is a single mechanism tuned to climbing-fiber activity that follows activity in vestibular pathways by approximately 100 msec.

Animals↗

Practice guidelines for community-based parenteral anti-infective therapy.

Practice guidelines for community-based parenteral anti-infective therapy (CoPAT) have recently been formulated in several countries. These guidelines emphasize the importance of teamwork and the interdisciplinary nature of CoPAT, and they use similar criteria for patient selection and evaluation, anti-infective agent selection and administration, and clinical monitoring. There are now guidelines or standards addressing the roles and responsibilities of the physician, nurse, and pharmacist in the delivery of CoPAT, and home care standards that address issues such as drug storage and preparation, treatment planning, and monitoring of ongoing care.

Anti-Bacterial Agents↗

Learning in the oculomotor system: from molecules to behavior.

A combination of system-level and cellular-molecular approaches is moving studies of oculomotor learning rapidly toward the goal of linking synaptic plasticity at specific sites in oculomotor circuits with changes in the signal-processing functions of those circuits, and, ultimately, with changes in eye movement behavior. Recent studies of saccadic adaptation illustrate how careful behavioral analysis can provide constraints on the neural loci of plasticity. Studies of vestibulo-ocular adaptation are beginning to examine the molecular pathways contributing to this form of cerebellum-dependent learning.

Animals↗

Community-based parenteral anti-infective therapy (CoPAT). Pharmacokinetic and monitoring issues.

Community-based parenteral anti-infective therapy (CoPAT) has, over the past 20 years, increased rapidly in many parts of the world including North America, Europe, South America and Australia. CoPAT is a multidisciplinary activity demanding close cooperation between nurses, pharmacists and physicians, as well as with the patient. The selection of an anti-infective drug for use outside the hospital setting must take into account not only the therapeutic effectiveness, cost effectiveness and safety of the drug, but also pharmacological factors such as the dosage schedule and the stability of the drug. Dosage schedules vary with pharmacokinetic factors (e.g. the use of drugs with long half-lives are favoured by CoPAT programmes) and pharmacodynamic features (e.g. once daily gentamicin therapy is attractive and practical because of concentration-dependent bactericidal killing and prolonged post-antibiotic effect). With selected drugs, the renal and, to a lesser degree, liver function of the patient will influence the dosage schedule. The mode of intravenous (i.v.) drugs administration will vary with volume considerations (limiting the use of syringe-infusion therapy for some drugs), stability issues (prevents drugs that are stable at room temperature for less than 24 hours from being used in multidose computerised delivery systems), as well as patient factors (ability to self administer an i.v. drug). Monitoring serum anti-microbial concentrations is undertaken to assure effectiveness and avoid toxicity, and is indicated for drugs with a narrow therapeutic window, such as the aminoglycosides. With the advent of the single daily dose administration of aminoglycosides, checking serum concentrations at the mid-point, i.e. 6 to 14 hours following administration of the first dose, is one approach. Because the toxic effects of vancomycin have been overstated, serum concentrations should only be obtained for defined indications primarily to assure therapeutic effectiveness.

Aminoglycosides↗

Behavioral analysis of signals that guide learned changes in the amplitude and dynamics of the vestibulo-ocular reflex.

We characterized the dependence of motor learning in the monkey vestibulo-ocular reflex (VOR) on the duration, frequency, and relative timing of the visual and vestibular stimuli used to induce learning. The amplitude of the VOR was decreased or increased through training with paired head and visual stimulus motion in the same or opposite directions, respectively. For training stimuli that consisted of simultaneous pulses of head and target velocity 80-1000 msec in duration, brief stimuli caused small changes in the amplitude of the VOR, whereas long stimuli caused larger changes in amplitude as well as changes in the dynamics of the reflex. When the relative timing of the visual and vestibular stimuli was varied, brief image motion paired with the beginning of a longer vestibular stimulus caused changes in the amplitude of the reflex alone, but the same image motion paired with a later time in the vestibular stimulus caused changes in the dynamics as well as the amplitude of the VOR. For training stimuli that consisted of sinusoidal head and visual stimulus motion, low-frequency training stimuli induced frequency-selective changes in the VOR, as reported previously, whereas high-frequency training stimuli induced changes in the amplitude of the VOR that were more similar across test frequency. The results suggest that there are at least two distinguishable components of motor learning in the VOR. One component is induced by short-duration or high-frequency stimuli and involves changes in only the amplitude of the reflex. A second component is induced by long-duration or low-frequency stimuli and involves changes in the amplitude and dynamics of the VOR.

Animals↗

The cerebellum: a neuronal learning machine?

Comparison of two seemingly quite different behaviors yields a surprisingly consistent picture of the role of the cerebellum in motor learning. Behavioral and physiological data about classical conditioning of the eyelid response and motor learning in the vestibulo-ocular reflex suggests that (i) plasticity is distributed between the cerebellar cortex and the deep cerebellar nuclei; (ii) the cerebellar cortex plays a special role in learning the timing of movement; and (iii) the cerebellar cortex guides learning in the deep nuclei, which may allow learning to be transferred from the cortex to the deep nuclei. Because many of the similarities in the data from the two systems typify general features of cerebellar organization, the cerebellar mechanisms of learning in these two systems may represent principles that apply to many motor systems.

Animals↗

Neural recordings and behavioral observations in the monkey vestibulo-ocular reflex constrain the cellular mechanisms for cerebellum-dependent behavioral learning.

Recordings from the cerebellum under behavioral conditions that cause learning in the vestibulo-ocular reflex (VOR) constrain the cellular mechanisms that could mediate learning. Analysis of the complex-spike responses of Purkinje cells demonstrates a mismatch between the properties of cerebellar long-term depression (LTD) in vitro and the signals available to guide learning in vivo. To resolve this mismatch, it may be necessary to assume that there are multiple cellular mechanisms of VOR learning, including both depression and potentiation.

Animals↗

Distributed input to the tail-siphon withdrawal circuit in Aplysia from neurons in the J cluster of the cerebral ganglion.

Plasticity in the circuits for the withdrawal reflexes has been correlated with several simple forms of nonassociative and associative learning in Aplysia, and biochemical, biophysical, and molecular mechanisms of plasticity in these circuits have been described. In order to examine network features of this plasticity, we identified and characterized a component of the modulatory circuitry for the tail-siphon withdrawal circuit. Activation of mechanoafferent neurons in the J cluster of the cerebral ganglion produced strong and distributed input to the tail-siphon withdrawal circuit. Stimulation of the J cells led to excitatory and inhibitory effects in the sensory neurons in the pleural ganglion, the tail motor neurons in the pedal ganglion, and several classes of interneurons in the pleural ganglion, including the multifunctional neuron LPI17. Activation of the J cells produced both fast and slow post-synaptic potentials in neurons of the tail-siphon withdrawal circuit. Of particular interest was the ability of the J cells to produce slow EPSPs in the pleural sensory neurons. These slow EPSPs were associated with an increase in the excitability of the sensory neurons, but no effect of the J cells on spike duration in the sensory neurons was observed. The J cells appear to mediate both sensory and modulatory inputs to the circuit for tail withdrawal.

Action Potentials↗

[Anomalies of the inclination of the occlusal plane: early treatment using indirect guide-planes--electromyographic response].

We discuss five cases of ANGLE's malocclusion Classes I, II or III that were rehabilitated basically by: restoration of masticatory function (previously pathological); the use of removable orthopaedic plates with indirect guideplanes. The patients (aged 6-15 years when treatment began) now have symmetrical balanced occlusion. Surface electromyography was used to study the function of the anterior temporal, surface masseter, deep masseter and anterior digastric muscles of 12 patients during rehabilitation of severe malocclusion. Electromyograms were obtained both with and without orthopaedic guideplanes installed. There were no significant differences as regards mean resting myoelectric activity. During maximum voluntary clenching in centric occlusion, the anterior temporal muscles were the most active, followed by the surface masseters. The activity of the anterior temporal muscles during clenching was significantly less (P < 0.01) with guideplanes than without. During lateral displacements, the non-working side anterior temporal muscle exhibited a significantly higher potential than the other muscles monitored, especially with guideplanes installed. The activity was lees with guideplanes during swallowing.

Adolescent↗

Ileal pouch-anal anastomosis. A single surgeon's experience with 100 consecutive cases.

Between August 1982 and November 1985, 100 patients underwent ileal "J" pouch-anal anastomosis (IPAA) at the University of Utah. All operations were performed in a standard fashion by a single surgeon. Seventy-eight patients were operated on for chronic ulcerative colitis and 22 for familial polyposis coli. Sixty of the patients were male and 40 were female with a mean age of 33.2 years and a range of 11-63 years. Mean +/- SEM operating time was 5.9 +/- 0.4 hours, blood loss was 666 +/- 49 ml, and total hospitalization was 10.1 +/- 0.3 days. No operative deaths occurred. The overall operative morbidity was 13% after IPAA. Clinical "pouchitis" was observed in 18 patients, all of whom were operated on for chronic ulcerative colitis. No patients had frank incontinence. Twenty per cent of patients experienced frequent nocturnal leakage in the early postoperative period with a significant improvement over the ensuing 6 months. Stool frequency at 1, 3, 6, 12, and 24 months was 7.5 +/- 0.2, 6.5 +/- 0.1, 6.2 +/- 0.3, 5.4 +/- 0.1, and 5.4 +/- 0.2, respectively. Stool frequency at 12 months correlated inversely with ileal pouch capacity and the diagnosis of familial polyposis. It is concluded that ileal pouch-anal anastomosis is a safe and effective operation for patients with chronic ulcerative colitis and familial polyposis coli.

Adolescent↗

Ileoanal pull-through: a new surgical alternative to ileostomy and a new challenge in diet therapy.

Colectomy mucosal proctectomy, and endorectal ileoanal pull-through is presently considered the best alternative for many patients with chronic ulcerative colitis, familial polyposis, and Gardner's syndrome. Although continence is achieved in nearly all patients who undergo the operation, high stool frequency and poor stool consistency are not infrequently encountered, particularly in the early postoperative period. Dietary control plays a likely role in postoperative management. At present, however, there are no published data to support specific dietary interventions. On the basis of our clinical experience and some preliminary study results, we have developed a comprehensive dietary regimen which is outlined in Table 1. Many questions in regard to the optimal diet for this patient population are presently unanswered, thus opening an exciting new area of nutrition research.

Anal Canal↗