Search PubMed⌕ Search

Biomedical subjects

J Ayers

Publications and source records attributed to J Ayers.

At least 19 recordsLinked to original sources
PubMed2001

Perioperative management of total parenteral nutrition, glucose containing solutions, and intraoperative glucose monitoring in paediatric patients: a survey of clinical practice.

Infants and children, particularly those who are chronically ill and maintained on total parenteral nutrition (TPN), are at risk for perioperative hypoglycaemia [blood glucose < 2.2 mmol x l(-1) (40 mg x dl(-1))] and hyperglycaemia [blood glucose > 11 mmol x l(-1) (200 mg x dl(-1))]. We surveyed paediatric anaesthesiologists regarding their perioperative management of blood glucose and TPN in paediatric patients to determine the current practice and its perceived success. Questionnaires were mailed to all members of the Study Group on Pediatric Anesthesia and the response rate was 70%. Results indicate that the current perioperative management of blood glucose and TPN is somewhat varied. Furthermore, greater than 10% of those surveyed report that their management results in a variable response in the maintenance of normoglycaemia. While the detrimental effects of perioperative hypoglycaemia and hyperglycaemia are rare, they are serious. A Medline search shows that no studies have been published regarding perioperative management of paediatric patients receiving TPN, although it appears that clinical study is warranted.

Blood Glucose↗
PubMed1996

HMO partnering: the provider dilemma.

While the growth of HMOs has slowed patient visits to doctors, it also has created a deluge of press clippings. On July 16, 1996, three articles on the subject appeared in the Wall Street Journal, front section. The headlines painted a vivid picture of the forces acting on HMOs and providers alike (Figure 1). The articles portended more change for healthcare. The "shake-out," a term applied to industries in serious transformation, brings shedding of excess capacity and loss of jobs and income. Providers, in particular, find themselves in a difficult dilemma. They must not only cut costs as reimbursement drops, but also retain patients with good outcomes and high quality service. Patient retention means keeping the individual patient from switching to another provider and keeping the insurer's group of patients as an authorized provider for that insurer. The relationship between provider and HMO lies at the heart of the provider dilemma. The HMO structure, which shifts financial risk for care, is quickly setting the standard, for healthcare pricing, medical standards, and management practices. Understanding and responding to HMO needs are vital to competitive advantage and survival. The article discusses the inherent dilemma of HMO and provider partnering and suggests provider responses.

Accounting↗
PubMed1995

Metamorphosis of spinal-projecting neurons in the brain of the sea lamprey during transformation of the larva to adult: normal anatomy and response to axotomy.

The spinal projecting system of the sea lamprey (Petromyzon marinus) has been used extensively in studies of axonal regeneration in both larvae and adults. However, little is known about the changes that are undergone by this system during metamorphosis. In order to determine the developmental changes in the size of the descending spinal projection and in the morphology of its neurons, larval, transforming, and adult lamprey brains were labeled by retrograde transport of horseradish peroxidase (HRP) injected into the spinal cord at 25% of body length. Examination of brain wholemount preparations revealed that the total number of labeled neurons doubled during metamorphosis. Most of this increase could be explained by elongation of reticulospinal axons from the rostralmost segments of the spinal cord to locations caudal to the injection site. There were no additions or deletions of either identified reticulospinal neurons or of reticulospinal nuclear groups between the larval and the adult stages. The proportions of Müller and Mauthner cells that were labeled reached a maximum of 93% during the early stages of metamorphosis. Axons of these neurons are known to project almost the entire length of the cord, even in larvae. Therefore, the efficiency of retrograde transport appears to be greater during metamorphosis than during larval or adult stages. While changes in efficiency of retrograde transport could account for some of the apparent increase in reticulospinal neuron numbers between larvae and animals undergoing metamorphosis, this could not contribute to the further increase in the apparent size of the reticulospinal system in the adult, since efficiency of retrograde labeling in these animals was lower than that at earlier stages. With retrograde labeling, a significant increase was seen in the profusion of dendritic arborization of some Müller and Mauthner cells during the early stages of metamorphosis. This correlated with an increase in the incidence of extreme axonal die-back, as indicated by the presence of retraction bulbs within the brainstem. However, intracellular injection of Neurobiotin in untransected animals showed similar degrees of dendritic arborization at all examined stages of development. Therefore, the dendritic profusion did not reflect developmental changes in neuronal morphology but rather reflected an increased sensitivity to axotomy during metamorphosis. We conclude that, during the transformation of the lamprey from the large larval to the adult form, there is little change in either the size or the dendritic morphology of the identified giant reticulospinal neurons. With respect to the smaller reticulospinal neurons, the distance of projection of many of their axons increases during metamorphosis, but there is very little increase in the number of reticulospinal neurons.

Animals↗
PubMed1993

Cytoarchitecture of spinal-projecting neurons in the brain of the larval sea lamprey.

The descending spinal projecting system of the lamprey is of interest because it includes axons that activate swimming pattern generators and because regeneration of this system is involved in the behavioral recovery of lampreys following spinal transection. However, little is known about the true size of this projection and of the distribution of its terminations along the spinal cord. Brain neurons with spinal projections were studied in larval sea lampreys by using wholemount preparations labeled retrogradely with horseradish peroxidase (HRP) from spinal injections at 10%, 15%, 25%, 50%, 70%, and 75% of body length from the anterior end. Neurons projecting to different levels of the spinal cord were mapped. A large number of descending axons terminated within nine segments caudal to the last gill. The spinal projection system was divided into 10 bilateral groups based on cytoarchitectural landmarks. All of the lateral nuclear groups had contralateral spinal projections. In addition to the 12 pairs of Müller cells, the pair of Mauthner cells, and the pair of auxiliary Mauthner cells described by previous authors, the study revealed four pairs of smaller neurons that were individually identifiable.

Animals↗
PubMed1993

Postoperative complications in patients with human immunodeficiency virus disease. Clinical data and a literature review.

OBJECTIVE: To compare complications after and outcome from surgical procedures between patients with human immunodeficiency virus (HIV) disease and a matched control population. DESIGN: Retrospective case review. SETTING: 476-bed university tertiary care center. PATIENTS: Of 343 patients diagnosed as having HIV disease between 1981 and September 1991, 26 (7.6 percent) were Walter Reed classifications system 3B or greater and underwent a surgical procedure with general anesthesia or, in the case of 2 patients, regional anesthesia, at the study hospital. These patients were matched to 26 control patients by severity of illness according to APACHE II severity of illness score and by age, sex, race, and anesthetic regimen. MEASUREMENTS AND RESULTS: The postoperative occurrence of dysrhythmia, hypotension, hypoxia, hemorrhage, renal insufficiency, or infection was evaluated in the study and control groups. Deaths within 3 and 30 days of the procedure and duration of survival after discharge from the hospital were recorded. Frequency of complications and 3- and 30-day mortality did not differ between the 2 groups. Duration of survival after discharge from the hospital in patients with HIV disease (7.4 +/- 9.7 months) was approximately 25 percent that in control patients (30.6 +/- 35.9 months) (p = 0.02). CONCLUSIONS: HIV disease does not increase the risk of postprocedural complications, including death, up to 30 days postprocedure. Thereafter, patients with HIV disease classified by the Walter Reed System as > or = 3B may survive for a shorter time than do equally ill patients who do not have HIV disease. Thus, needed surgical intervention should not be limited based on HIV status and concern for subsequent complications.

Adult↗
PubMed1991

Gross, microscopic and ultrastructural lesions of protoporphyria in Limousin calves.

The gross, microscopic and ultrastructural lesions associated with the genetic disease, protoporphyria, in Limousin cattle were studied in detail. The clinical signs and lesions were most severe in young animals. In the liver, the lesions consisted of portal fibroplasia, bile ductule hyperplasia, parenchymal cell swelling, and pigment accumulation. Maltese cross-like crystals were evident under polarized light. Ultrastructurally, there were large secondary lysosomes comprised of electron-dense granules associated with lipid droplets in hepatocytes. Phagocytic cells in the dermis also contained large heterogeneous secondary lysosomes.

Animals↗
PubMed1989

Steroid secretion by a virilizing lipoid cell ovarian tumor: origins of dehydroepiandrosterone sulfate.

A 78-year-old woman had a 3-year history of severe virilization caused by a lipoid cell ovarian tumor localized by pelvic ultrasound examination and NP-59 scan. Steroid secretion was evaluated by the following: 1) peripheral plasma levels before and after hormonal stimulation with ACTH or hCG, 2) venous catheterization and measurement of steroid levels in the left and right ovarian veins during surgery, 3) measurements of enzymatic activities in the tumor tissue compared with those in normal ovarian tissue, and 4) steroid secretion studies in vitro of the tumor tissue, surrounding tissue, and contralateral ovarian tissue. The tumor tissue secreted both delta 5 and delta 4 androgens, including dehydroepiandrosterone sulfate. Dehydroepiandrosterone sulfate was also secreted by the surrounding and contralateral ovarian tissue.

Aged↗
PubMed1987

Plasticity of fin command system function following spinal transection in larval sea lamprey.

The descending control of dorsal fin posture by a reidentifiable reticulospinal command neuron (I1), was examined in the sea lamprey, Petromyzon marinus. Intracellular stimulation of I1 controls the posture of both dorsal fins. Spinal transection between the fins results not only in loss of control of posterior dorsal fin posture, but after 2 h, the control of the anterior dorsal fin as well. Anterior dorsal fin responses remained absent at 4, 5 and 6 days after transection. Stimulation of I1 could control anterior dorsal fin posture in specimens which had recovered the ability to right during swimming (77 and 100 days after transection), although higher than normal stimulus frequencies were required. I1 control of posterior dorsal fin posture did not recover.

Animals↗
PubMed1984

The relationship of I-131 6 beta-iodomethyl-19-norcholesterol (NP-59) adrenal cortical uptake to indices of androgen secretion in women with hyperandrogenism.

Dexamethasone suppression (DS) adrenal cortical scintigraphy has been shown to be useful in the detection of the adrenal pathology in women with hyperandrogenism. However, a relationship between adrenal cortical uptake of I-131 6 beta-iodomethylnorcholesterol (NP-59) and the level of adrenal androgen secretion has not been established. A retrospective analysis of DS adrenal scintiscans has been performed on 39 women with hirsutism and hyperandrogenism. In 14 patients with normal patterns of imaging, in vivo adrenal gland iodocholesterol uptake, calculated using a semi-operator-independent-computer algorithm, did not correlate with the excretion of urinary 17-ketosteroids (17-KS). In contrast, in 20 patients demonstrating abnormal bilateral early imaging patterns, adrenal gland NP-59 uptake correlated significantly with the level of urinary 17-KS excretion (r = 0.65, P less than 0.05). To date seven of these 20 patients have had confirmatory procedures documenting the adrenal glands as contributing sites of androgen secretion. A similar correlation with urinary 17-KS excretion was seen in five other patients with unilateral imaging patterns (r = 0.94, P less than 0.005), due to androgen-secreting adrenal cortical adenomas. No correlation between adrenal NP-59 uptake and plasma testosterone or dehydroepiandrosterone sulphate levels was observed in any of the groups. Thus, adrenal gland uptake of NP-59 under DS reflects a measure of androgen secretion in women with androgen excess.

17-Hydroxycorticosteroids↗
PubMed1984

Synaptic perturbation and entrainment of gastric mill rhythm of the spiny lobster.

The gastric mill rhythm of the lobster stomatogastric ganglion was perturbed with short trains of synaptic input from the inferior ventricular nerve (IVN) through fibers. The stimulus was delivered randomly for phase-response curve analysis or repetitively to examine entrainment. The responses depend on the phase of the stimulus in the endogenous rhythm. The stimulus may alter the internal coordination of the motor pattern. Stimuli that occur during a lateral gastric nerve-anterior lateral nerve-E-neuron (LG-GM-E) burst perturb the burst internally and produce a prolonged LG-GM-E burst, while those that occur during the silent interval between LG-GM-E bursts may evoke a triggered LG-GM-E burst. Spontaneous, prolonged, and triggered LG-GM-E bursts differ in their internal structure as well as the order of burst onsets and offsets. The intercalated triggered LG-GM-E burst delays the occurrence of the subsequent spontaneous LG-GM-E burst, thus strongly resetting the rhythm. These resetting effects have been formalized by phase-response curve analysis. Over limited constraints, cyclic IVN stimuli can entrain the rhythm. Repetitively delivered IVN stimuli have parametric effects on the rhythm that mask the predictive value of phase-response curve analysis for the determination of the phase relations during entrainment.

Animals↗
PubMed1983

Regeneration of locomotor command systems in the sea lamprey.

Ammocoete larvae of the sea lamprey were allowed to recover from a complete transection of the spinal cord posterior to the last gill arch. Specimens were then prepared for focal extracellular stimulation of the brainstem in the region known to contain the command systems for swimming. In 4 preparations where behavioral recovery had occurred, stimulation in this region would initiate swimming, indicating that the command function of this 'locomotor' region had recovered.

Animals↗
PubMed1983

Which behavior does the lamprey central motor program mediate?

The isolated lamprey spinal cord, when bathed in 2 millimolar D-glutamic acid, will generate a pattern of motor neuron discharge that has generally been assumed to represent the central motor program for swimming. Motion pictures of behaving lampreys were analyzed by a computer algorithm to estimate undulatory movement parameters that could be directly compared with those generated during D-glutamate--induced undulations. The D-glutamate--induced movement parameters were significantly different from those observed during normal behaviors, including swimming, but accurately predicted the undulations produced by spinally transected adult lampreys.

Animals↗