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Biomedical subjects

J Hayden

Publications and source records attributed to J Hayden.

At least 37 records · Page 2Linked to original sources
PubMed1995

Growth plate pathology in feline mucopolysaccharidosis VI.

The mucopolysaccharidoses (MPS) are a family of lysosomal storage diseases that result from the accumulation of partially catabolized glycosaminoglycans (GAGs) within lysosomes. A characteristic of most affected individuals is radiographic evidence of symmetrical epiphyseal dysplasia, with short stature and degenerative joint disease. Although there is evidence of epiphyseal dysfunction, little is known of the changes that occur at the morphological level. The growth plate of the femoral head was studied by light and electron microscopy in five cats with MPS VI (Maroteaux-Lamy syndrome, arylsulfatase B deficiency) and 12 normal cats. Compared with the normals, the MPS VI cat growth plates exhibited poorly organized proliferative zones, an almost total loss of column formation in the hypertrophic zone, an uneven chondro-osseous junction, a disorganized calcifying cartilage zone, and abnormal or reduced numbers of osteoclasts. By electron microscopy, the cytoplasm of affected cat chondrocytes was filled with membrane-bound vacuoles. Together these findings indicate that the MPS diseases cause major changes in growth plate structure and function.

Animals↗
PubMed1995

Help wanted. Nurse or health educator?

Although health education may be considered a component of nursing, trained professionals exist whose sole focus is health education. For optimal results, these health education specialists, not nurses, are the ones hospitals and healthcare organizations should seek out when staffing their departments of health education.

Activities of Daily Living↗
PubMed1995

Audit as part of summative assessment of vocational training.

Written evidence of the ability to carry out audit and performance review looks likely to be one of the four components of a summative assessment package for the end of vocational training. This paper seeks to raise the issues involved in this process. The features of audit which lend themselves to assessment of the attributes of a general practitioner are discussed. The criteria which might be used to assess a written submission are presented. A possible mechanism for marking and grading is suggested, and strategies for optimizing the validity and reliability of that assessment discussed. A timescale for implementation is also suggested. These issues need to be discussed and a process piloted if a credible mechanism is to be in place by August 1996.

Education, Medical, Graduate↗
PubMed1993

The condom race.

The condom race is a hands-on activity that can help teach young people condom use as part of safer sex practices. Although it is well documented that students know about condom use, they often do not do what they know they should. One possible explanation for this is that the students may lack the skills and confidence they need to have when they use condoms. The condom race offers students a chance to gain skills and confidence in a humorous, nonthreatening way. During the exercise, which is based on the concept of a relay race, students touch, feel, and practice putting condoms on penis models. After participating in the activity, students reported increased confidence in their ability to use, discuss, and carry condoms. The condom race is a quick, amusing, and easy activity.

Adolescent↗
PubMed1993

Intravenous sedation for MR imaging of the brain and spine in children: pentobarbital versus propofol.

The authors present a prospective study of single-agent pediatric sedation regimens for patients older than 2 years of age undergoing magnetic resonance (MR) imaging of the brain and spine. Thirty patients underwent MR imaging after intravenous administration of pentobarbital in successive boluses of 2.5 mg/kg to a maximum of 7.5 mg/kg. Thirty-one patients received an intravenous bolus followed by continuous infusion of propofol. The dosage schedule for propofol was 2 mg/kg (with supplemental 1 mg/kg boluses) followed by continuous infusion of 6 mg/kg per hour. There was no significant difference in the physiologic response to sedation between the two groups, although the magnitude of the drop in pulse was significantly greater in the group receiving propofol. Three patients receiving propofol experienced transient decreases in oxygen saturation, at variable times over the course of the procedure. However, patients recovered significantly faster from sedation with propofol. While propofol may represent a viable alternative to pentobarbital in selected patients, propofol requires constant physician supervision and meticulous technique.

Brain↗
PubMed1991

Acute coronary artery dissection during pregnancy.

Acute coronary artery dissection is a rare complication of pregnancy usually identified at postmortem examination. We report a case of myocardial infarction apparently caused by acute dissection of the left main coronary artery in a 24-year-old woman being treated for preterm labor with terbutaline. Hemodynamic deterioration necessitated emergency cesarean delivery and coronary bypass surgery.

Journal Article↗
PubMed1990

Brucellosis: an unusual cause of fever in Kentucky.

Human infection with brucellosis appears to be very uncommon in Kentucky. Only three cases have been reported to the Kentucky Department of Health, Frankfort, in the last 4 years. It is suspected, however, that brucellosis is severely underdiagnosed and under-reported in the United States. A patient recently diagnosed with acute systemic brucellosis reminds us that this illness may still be seen in the Commonwealth.

Acute Disease↗
PubMed1989

A comparison of growth regulation of mammalian with amphibian lens epithelium.

In frogs hypophysectomy causes cell proliferation in lens epithelium to subside entirely, with better than 95% of the cells arresting in G1. The phenomenon has been traced to the action of insulin-like growth factors (IGFs) whose synthesis depends on anterior pituitary hormones, most notably GH. Both GH and purified somatomedin C can reinitiate mitosis in the lenses of hypophysectomized frogs. The present studies were done to determine if growth of rat lenses is controlled as is that of amphibia. It appears this may not be so because hypophysectomy has no effect on division in the rodent system. Protein calorie malnutrition (PCM) reduced the mitotic index and this effect is much enhanced by pituitary ablation. Of interest too, were the observations that the glucocorticoid, dexamethansone, is inhibitory in frog; the effect in rat is uncertain. Injection of bovine pituitary powder has no influence on rat while stimulating the amphibian material. It is therefore possible to modify growth of rat lens epithelium in vivo but the regulating mechanism(s) appears to be distinct from that operating in frogs. Whether the difference(s) is inherent in the cells themselves or is to be sought in the access routes through which they are reached by blood borne factors (e.g. permeability of blood-aqueous barriers) is, at present, unclear.

Animals↗
PubMed1989

A control unit for maximal-rate continuous tissue expansion (CTE).

Subcutaneous or submuscular tissue expansion has become a major tool for the reconstructive plastic surgeon in the repair of difficult wounds and in breast reconstruction. This technique can provide additional or replacement tissue with good match in color, sensation, texture and adnexal characteristics. A major limitation of the technique is the time required for periodic tissue expansion to the required volume in the clinical setting, typically taking from a few weeks to several months. Conceptually, the maximum rate possible for safe clinical tissue expansion would result from continuous maintenance of tissue expander pressure just below capillary filling pressure (continuous tissue expansion, CTE). A control device with this capability would have important clinical and research applications. A self-contained portable control unit (patent pending) for CTE has been designed, fabricated, and testing initiated in a dog model. The 4-lb unit includes a 250-cc fluid reservoir, power pack, pressure transducer (Microswitch 160 PC), pump (Spalding 701A), feedback circuits and memory (2-lb power pack, 2-lb controller and reservoir). Preselected constant pressure (15-50 mmHg +/- 0.1 mmHg) can be maintained in a tissue expander with a maximal flow rate of 16 cc/hr for approximately 18 hours before change of the NiCad battery pack. A digital memory records pressure and volume infused and transfers this data to a Macintosh computer after completion of expansion. Verification of this prototype control unit is presently underway. Initial data suggests that the time required for complete filling of a subcutaneous tissue expander in a dog model can be reduced to approximately 72 hours. Several potential clinical applications and variations of this device are discussed.

Animals↗
PubMed1987

Effect of epidermal growth factor on growth and postnatal development of the rabbit liver.

The effect of epidermal growth factor (EGF) on the postnatal development of the liver was examined. New Zealand White rabbits received 40 micrograms.kg-1.day-1 EGF from days 3 to 17 of age either intraperitoneally or orogastrically, whereas controls received saline. At days 18-20, animals underwent cannulation of the common duct using halothane anesthetic. Biliary output was measured directly for three 1-h periods: under basal conditions and in response to intravenous infusion of exogenous glycodeoxycholic acid at 0.75 and 1.5 mumol.min-1.kg-1, respectively. The bile salt pool size was measured by isotope dilution. Final mean body weight of intraperitoneal and orogastric groups did not differ from controls. Liver we weight, DNA, and protein content were significantly increased in intraperitoneally treated animals without morphological or biochemical evidence of fat deposition. Both intraperitoneal and orogastric EGF significantly increased bile salt secretion in the basal period and as a response to exogenous bile acid infusion. Bile flow was significantly increased in response to 1.5 mumol.min-1.kg-1 infusion of glycodeoxycholic acid. The bile salt pool was increased by both intraperitoneal and orogastric EGF. Administration of EGF resulted in a precocious development of glucokinase (EC 2.7.1.2) activity in the liver. EGF had no effect on serum cortisol, corticosterone, triiodothyronine, thyroxine, or free thyroxine levels. These findings suggest that in the neonatal period EGF can promote hepatic growth and maturation.

Animals↗
PubMed1985

Effect of epidermal growth factor on ontogeny of the gastrointestinal tract.

The effect of epidermal growth factor (EGF) on the ontogeny of the gastrointestinal tract was examined in New Zealand White rabbits. EGF, 40 micrograms X kg-1 X day-1, was administered to suckling animals from 3-18 days of age either intraperitoneally or orogastrically. Controls received saline. Animals were killed at 17-18 days of age. Body weight and wet weight of stomach, pancreas, and 10-cm segments of proximal, mid, and distal small intestine were measured. The total pancreas was homogenized for determination of protein, DNA, and amylase, and the intestinal mucosa was scraped, weighed, and homogenized for estimation of protein, DNA, sucrase, and lactase. While body weights were similar wet weight of stomach and pancreas were increased by intraperitoneal and orogastric EGF. Small intestinal wet weights were increased in all segments by intraperitoneal but not orogastric EGF, and both routes significantly increased mucosal DNA in the distal segment. EGF administered orogastrically induced precocious maturation of intestinal brush-border disaccharidase activities but had no effect on pancreatic amylase, whereas EGF administered intraperitoneally induced precocious maturation of pancreatic amylase but had no effect on brush-border disaccharidase activities. These findings suggest that both systemic and oral EGF play a role in regulating growth and postnatal maturation of the gastrointestinal tract.

Amylases↗
PubMed1984

Respiratory symptoms and pulmonary function of welders in the engineering industry.

We have studied respiratory symptoms, smoking habits, chest radiographs, sickness absence, and pulmonary function among 258 welders and an equal number of matched control subjects in three engineering factories. Welders who smoked had a higher frequency of chronic phlegm production than control subjects but there was no difference in cough or dyspnoea. The frequency of abnormality on chest radiographs was low and similar in welders and controls. Upper respiratory infections were a more frequent cause of sickness absence in welders than in controls but no difference was found in other respiratory diseases. FEV1 and peak expiratory flow rate were similar in welders and controls. In a subset of 186 subjects the maximum expiratory flow rate at low lung volumes was significantly less in welders who smoked than in control subjects who smoked, but there was no difference in non-smokers. Welders working under these conditions in the engineering industry appear to have no increased risk of chronic obstructive lung disease.

Absenteeism↗