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Biomedical subjects

J Gates

Publications and source records attributed to J Gates.

At least 37 records · Page 2Linked to original sources
PubMed1996

Development, plasticity and evolution of butterfly eyespot patterns.

The developmental and genetic bases for the formation, plasticity and diversity of eyespot patterns in butterflies are examined. Eyespot pattern mutants, regulatory gene expression, and transplants of the eyespot developmental organizer demonstrate that eyespot position, number, size and colour are determined progressively in a developmental pathway largely uncoupled from those regulating other wing-pattern elements and body structures. Species comparisons and selection experiments suggest that the evolution of eyespot patterns can occur rapidly through modulation of different stages of this pathway, and requires only single, or very few, changes in regulatory genes.

Adaptation, Biological↗
PubMed1995

Safety of intravenous valproate.

This multicenter, open-label trial was designed to study the safety of intravenous (IV) sodium valproate in patients with epilepsy. All 318 patients (previously treated with antiepileptic drugs) were hospitalized for seizure control or anticipated seizures. The protocol allowed physicians to set the number of infusions and treatment duration. Adverse events, laboratory studies performed, and seizure activity were documented on case report forms. The patients' mean age was 34.4 years (range, 2-87 years). The most common reason for admission was lack of seizure control (235 patients, 185 of whom were admitted for video-electroencephalographic monitoring). The median dosage of valproate was 375 mg infused over 1 hour. The median number of doses was four, given over 2 days. In 54 patients (17%), transient adverse events were reported. The most frequent were headache, reaction at the injection site, and nausea (2.2% each); somnolence (1.9%); vomiting (1.6%); and dizziness and taste perversion (1.3% each). No persistent or severe hematologic or serum chemistry abnormalities were found. Vital signs were not significantly affected by the IV infusion of valproate. At the dosages and rates of administration studied, intravenous valproate appears to be safe and well tolerated.

Adolescent↗
PubMed1994

Evolution of homeotic gene regulation and function in flies and butterflies.

It has been proposed that the evolution of homeotic genes parallels, and to some degree directs, the evolution of segment diversity in the myriapod-insect lineage. But the discovery of discrete Antennapedia complex (ANT-C) and bithorax complex (BX-C) gene members in crustacea, chelicerates, annelids and various insects, as well as in vertebrates, indicates that the expansion and diversification of homeotic genes preceded the diversification of arthropods and insects. How, then, have these genes influenced the evolution of body plans? To address this question, we now examine homeotic gene expression and regulation in butterflies (Lepidoptera), which, unlike flies, possess larval abdominal limbs and two pairs of wings. We show that the difference in larval limb number between these insects results from striking changes in BX-C gene regulation in the butterfly abdomen, and we deduce that the wing-patterning genes regulated by Ultrabithorax have diverged in the course of butterfly and fly evolution. These findings have general implications for the role of homeotic genes in animal evolution.

Amino Acid Sequence↗
PubMed1994

Pattern formation and eyespot determination in butterfly wings.

Butterfly wings display pattern elements of many types and colors. To identify the molecular processes underlying the generation of these patterns, several butterfly cognates of Drosophila appendage patterning genes have been cloned and their expression patterns have been analyzed. Butterfly wing patterns are organized by two spatial coordinate systems. One system specifies positional information with respect to the entire wing field and is conserved between fruit flies and butterflies. A second system, superimposed on the general system and involving several of the same genes, operates within each wing subdivision to elaborate discrete pattern elements. Eyespots, which form from discrete developmental organizers, are marked by Distal-less gene expression. These circular pattern elements appear to be generated by a process similar to, and perhaps evolved from, proximodistal pattern formation in insect appendages.

Amino Acid Sequence↗
PubMed1992

Complications of colostomy performed on gynecologic cancer patients.

From 1/1/80 to 5/31/90 111 patients underwent a colostomy on a gynecologic oncology service. Six patients developed 7 (6.3%) early colostomy-related complications, including sepsis (1), stomal retraction (1), ostomy wound infection (3), and partial stomal obstruction (2). The sepsis was felt to be related to spillage of stool upon maturing the colostomy, and this patient expired on Postoperative Day 63. There were no other mortalities attributed to the colostomies. Fourteen patients developed 17 (15.3%) delayed colostomy-related complications, including parastomal hernia (5), stomal retraction (1), stomal prolapse (3), tumor replacement (2), and site-choice problems (6). These results compare favorably with those in the literature and support the continued role of the gynecologic oncologist in gynecologic cancer-related gastrointestinal surgery.

Adult↗
PubMed1992

Septal His-Purkinje ventricular pacing in canines: a new endocardial electrode approach.

Ventricular activation sequences and cardiac performance are influenced by pacing sites. Stimulation of or close to the specialized atrioventricular (AV) conduction system optimizes paced ventricular function compared to alternative epi- or endocardial muscle conduction sites. This study reports a new endocardial electrode implant approach to approximate septal His-Purkinje ventricular pacing. Five 6-month-old beagles were used. A custom, platinum-iridium, exposed helical screw electrode (Medtronic, Inc.), 4.5-mm long, with a 17.8-mm2 surface area, was designed with a polyurethane covered 4 filar MP35N nickle conductor lead. An 8 French sheath (USCI, Inc.) was modified as introducer to permit simultaneous implant intracardiac pressure and electrogram recordings. Following a thoracotomy, the introducer was inserted through the right atrial appendage and advanced to record optimal His-bundle electrogram while maintaining atrial pressure along the septal tricuspid valve annulus. After electrode implant, ECG demonstrated narrow paced QRS morphology. Mean implant values showed sensed R wave 6.3 mV, slew rate 0.65 V/sec, pacing impedance 319 ohms, and threshold 0.9 V/3.3 mA at 0.5-msec output. Necropsy showed implant above the tricuspid annulus with electrode extension into and contained within the proximal ventricular septum. This study demonstrates that an endocardial septal approach to His-Purkinje ventricular pacing to optimize paced ventricular function is feasible with a new electrode design and precise septal implant technique. Alternative introducer designs may permit transvenous application of this approach.

Animals↗
PubMed1992

Increased energy intake minimizes weight loss in men at high altitude.

The hypothesis that high-altitude weight loss can be prevented by increasing energy intake to meet energy requirement was tested in seven men, 23.7 +/- 4.3 (SD) yr, taken to 4,300 m for 21 days. Energy intake required to maintain body weight at sea level was found to be 3,118 +/- 300 kcal/day, as confirmed by nitrogen balance. Basal metabolic rate (BMR), determined by indirect calorimetry, increased 27% on day 2 at altitude and then decreased and reached a plateau at 17% above the sea level BMR by day 10. Energy expended during strenuous activities was 37% lower at altitude than at sea level. Fecal excretion of energy, nitrogen, total fiber, and total volatile fatty acids was not significantly affected by altitude. Energy intake at altitude was adjusted after 1 wk, on the basis of the increased BMR, to 3,452 +/- 452 kcal/day. Mean nitrogen balance at altitude was negative (-0.25 +/- 0.71 g/day) before energy intake was adjusted but rose significantly thereafter (0.20 +/- 0.71 and 0.44 +/- 0.66 g/day during weeks 2 and 3). Mean body weight decreased 2.1 +/- 1.0 kg over the 3 wk of the study, but the rate of weight loss was significantly diminished after the increase in energy intake (201 +/- 75 vs. 72 +/- 48 g/day). Individual regression lines drawn through 7-day segments of body weight showed that in four of seven subjects the slopes of body weight were not significantly different from zero after the 2nd wk. Thus weight loss ceased in four of seven men in whom increased BMR at altitude was compensated with increased energy intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Transcranial magnetic stimulation in patients with epilepsy.

We studied the effects of transcranial magnetic stimulation (TMS) applied in trains of 8- to 25-Hz stimuli on electroencephalographic epileptiform activity on eight patients being evaluated for epilepsy surgery. We performed the stimulation with a round water-cooled stimulation coil held flat on the scalp and centered over different positions of the International 10-20 System. We were unable to trigger seizures or induce epileptiform discharges arising from the epileptic focus in any of the eight patients with any of the stimulation protocols. However, we induced a partial motor seizure from the contralateral hemisphere to the exclusive temporal focus in the only patient stimulated with 100% maximal intensity. Precautions have to be taken when applying rapid TMS to patients because of the risk of seizure induction. Our results do not support the view that TMS specifically activates the epileptic foci.

Electric Stimulation↗
PubMed1991

Coping with rapid advancements.

The explosion of technology has hit radiology with more force than any other specialty, says the author of this month's special expanded feature. The immediate past president of the Iowa Radiological Society--a Burlington Radiologist--discusses the current developments in his specialty and the goals of the specialty society.

Goals↗
PubMed1990

Discrimination of normal and at-risk preschool children on the basis of neurological tests.

A set of neurological tasks was administered to normal three- and five-year-old preschool children as well as to equal-age children identified as being at-risk for learning disabilities. 12 neurological test items were identified that differentiated normal from at-risk children at one or both ages. Follow-up of the five-year-olds at age seven showed a significant linear relation between scores on neurological tasks and the Wechsler Intelligence Test for Children. The neurological examination at age five also had predictive value regarding class placement at age seven. The findings suggest that a simple neurological test may be helpful for the early identification of preschool children who are at risk for learning difficulties.

Brain Damage, Chronic↗
PubMed1989

Comparison of the effects of IL-1 alpha and TNF-alpha on phagocyte accumulation and murine antibacterial immunity.

IL-1 and TNF both are reported to increase host antibacterial resistance. To directly compare their effects on tissue phagocyte accumulation and antibacterial activity, we infused recombinant human IL-1 alpha and TNF-alpha into C3H/HeJ mice. Although IL-1, at a dose of 1 microgram/day, did not significantly elevate blood neutrophil concentrations, it increased the number of PMNs within the spleen three to fourfold within 2 days. Similar neutrophil accumulation also occurred in the lungs, bone marrow, and liver of treated animals without detectable changes in macrophage numbers. IL-1 also increased myelopoiesis in the spleen by Days 3-4 of infusions. The capacity of splenocytes from IL-1-treated animals to kill Listeria monocytogenes in vitro and to suppress listeria proliferation in vivo after the intravenous infusion of bacteria both rose in parallel with PMN accumulation. Comparable doses of TNF also enhanced listeria killing in vivo but in contrast to IL-1, it significantly depressed peripheral blood neutrophil counts, and inhibited splenic neutrophil accumulation and in vitro listericidal activity in listeria-infected mice. Our results suggest that IL-1 enhances host resistance to infection by increasing tissue neutrophil accumulation while TNF protects by a different mechanism, despite a net inhibitory effect on neutrophil accumulation.

Animals↗
PubMed1989

Interhemispheric transfer in patients with incomplete section of the corpus callosum. Anatomic verification with magnetic resonance imaging.

Tests of interhemispheric disconnection including visual, somesthetic, kinesthetic, auditory, and complex motor functions were performed on seven patients with chronic epilepsy who had undergone partial surgical section of the corpus callosum, verified by magnetic resonance imaging. Two patients with only one third of the splenium remaining demonstrated disconnection syndromes involving all modalities except vision, which was completely intact. Five patients had lesions involving the rostrum and the anterior two thirds to four fifths of the body of the callosum, with the splenium spared. They demonstrated little evidence of disconnection in the modalities indicated, except for left ear suppression on a dichotic listening task and partial somatosensory disruption in some cases. These results emphasize the importance of the posterior corpus callosum for interhemispheric sensory and sensorimotor transfer, although some discrepancies between current behavioral data and previous anatomic findings remain.

Adolescent↗