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Biomedical subjects

P G Fitzgerald

Publications and source records attributed to P G Fitzgerald.

At least 19 recordsLinked to original sources
PubMed2001

Evolutionary attempts at 4 eyes in vertebrates.

PURPOSE: To understand and compare the optical, histological, and ecological differences among 4 vertebrate species that have had evolutionary attempts toward 4 eyes. METHODS: An evolutionary attempt at 4 eyes in defined as the duplication or one or more structures integral to the refraction or interpretation of the visible spectrum for that animal. We reviewed and compared the known optics, histology, and ecology of each of these vertebrate species with attempts at 4 eyes including Anableps anableps, Dialomnus fuscus, Mnierpes macrocephalus, and Bathylychnops exilis. These animals have developed portions of ancillary eyes that have diverged from the primary globe in 3 different patterns. At least 1 specimen of each of those vertebrate species known to have 4 eyes was examined histologically and compared to the animal's ecology and current cladistic relationship. RESULTS: A anabteps has 2 distinct optical systems in each eye: an upper one for aerial vision and a lower system for aquatic vision. These systems feature separate retinae and an asymmetric lens to achieve focus in the aerial and aquatic vision, but only 1 optic nerve per eye. The visual system is split horizontally to function optimally in a "prone" position in the water. D fuscus is a terrestrial feeder and has a vertically (almost perpendicular to the long axis of the fish) divided cornea using pigment and a condensation of collagen as the divider, a single pupil, and a divided retina. The split cornea allows for the fish to remain vertical with 1 cornea in air and 1 cornea in water. M macrocephalus is probably closely related to D fuscus with a similar split cornea. B exilis is a mesopelagic inhabitant living at approximately 200 to 1,000 m and has an ancillary globe that "buds" off the primary globe. This secondary globe is directed inferiorly toward the ocean floor as compared to the primary globe, which is directed 35 degrees superiorly from the horizontal. Adult species of B exilis have 2 additional scleral bodies suspected to be lenses. If so, these structures would be capable of focusing light from the inferior field onto the superior retina, presumably adding to the panoramic inferior visual field. There are other mesopelagic species, including Styleophorus chordatus, Opisthoproctus grimaldii, Scopelarchus gantheri (or guentheri), Dolichopteryx binocularis, Benthalbella infans, and Evermannella indica, that have other unusual ocular mechanisms, such as retinal diverticulae and lens pads capable of reflection, but do not meet the definition of multiple eyes, as defined for purposes of this work. CONCLUSIONS: D fuscus and M macrocephalus are terrestrial feeders requiring aquatic and aerial vision, and hence have a split cornea for this purpose, and they probably use their anterior corneae for terrestrial vision. A anableps swims at the surface with combined aerial and aquatic vision for feeding and protection from predators. B exilis is a mesopelagic feeder requiring a binocular visual field in the horizontal meridian and above, and simultaneously is a bottom scavenger using an ancillary globe and perhaps scleral lenses for recognition of bioluminescent detritus. Although 2 of these models are related (D fuscus and M macrocephalus), these 4 fish represent 3 separate, distinct, and unrelated convergent evolutionary attempts toward 4 eyes in vertebrates satisfying the ecological needs of each. The 3 different models are unrelated evolutionarily and are found in 3 separate orders.

Animals↗
PubMed1999

Mucous fistula refeeding in neonates with short bowel syndrome.

BACKGROUND/PURPOSE: Neonates with enterostomies commonly suffer from a functional short bowel syndrome (SBS) and have a greater risk of electrolyte and fluid loss with poor weight gain. The authors describe their experience with refeeding stoma effluent into the mucous fistula in neonates. METHODS: A 5-year (1993 to 1997) chart review of neonates with stoma effluent refeeding was undertaken. Demographics, medical history, surgical procedures, timing, and duration of refeedings were reviewed. Enteral and total parenteral nutritional (TPN) requirements, electrolyte, and acid-base disturbances were recorded. RESULTS: Six neonates (gestational ages of 27 to 38 weeks, birth weights of 533 to 3400 g) were identified with nutritional or electrolyte complications before the commencement of refeeding. Enterostomy indications included necrotizing enterocolitis (n = 2), intestinal atresia type 3b (n = 1), complications from ruptured omphalocoele (n = 1), congenital adhesive band obstruction (n = 1), and midgut volvulus after congenital diaphragmatic hernia repair (n = 1). Weight gain during refeeding ranged from 5 to 25 g/kg/d with duration of refeeding lasting 16 to 169 days (two neonates were refed at home) until reanastomoses were done 6 to 44 weeks after the original surgery. There were no complications, and TPN requirements were diminished or eliminated. CONCLUSION: This technique represents a simple and safe method, which lessens the need for TPN and electrolyte supplementation in neonates with enterostomies and SBS before reanastomosis.

Enteral Nutrition↗
PubMed1997

Histopathologic analysis of interval appendectomy specimens: support for the role of interval appendectomy.

The treatment of appendiceal abscess is controversial. For patients initially treated "conservatively" with antibiotics with or without drainage, the role of interval appendectomy is an area of considerable debate. Without interval appendectomy, the true risks of recurrent disease and missed pathological findings are uncertain, and large, long-term, prospective studies are unavailable. To evaluate the role of interval appendectomy, the authors reviewed the histopathologic specimens from patients with presumed appendiceal abscess treated by interval appendectomy. Over a 7-year period, 162 children presented with a clinical diagnosis of perforated appendicitis. Eighteen patients had localized abscesses treated conservatively, followed by interval appendectomy. Standard histopathologic sections of 17 of the 18 appendices were examined by one pathologist who was blinded to the clinical data and to the interpretation of the original pathologist. Of the 11 boys and seven girls (mean age, 7.4 +/- 3.4 years), eight underwent percutaneous drainage and one underwent operative drainage. All received intravenous antibiotics for a mean of 8.6 +/- 3.2 days with a hospital stay of 10.4 +/- 8.3 days. Interval appendectomy was performed at a mean of 92.7 +/- 20.7 days after initial admission, with discharge at a mean of 2 +/- 1.3 days after surgery. There were no complications or deaths. Histopathologic review showed normal appendix (n = 4), normal appendix with mild serositis (n = 6), normal appendix with unsuspected resolved Meckel's diverticulitis (n = 1), appendiceal duplication (n = 1), granulomatous appendicitis (n = 3), and acute appendicitis (n = 2). All appendices had patent lumens, and 15 were documented to be present to the tip. There was no correlation between the histopathologic findings and the interval between abscess and interval appendectomy. Interval appendectomy was performed with no morbidity and a short hospital stay. Two patients had histopathologic recurrent acute appendicitis, five had unsuspected pathological findings (appendiceal duplication, Meckel's diverticulitis, granulomatous inflammation), and none of the appendices had an obliterated lumen, suggesting that all patients were at long-term risk for recurrent disease. These data support the role of interval appendectomy in cases of perforated appendicitis treated conservatively.

Abscess↗
PubMed1996

Pediatric laparoscopic splenectomy using the lateral approach.

Laparoscopic splenectomy in children has been shown to be safe, to reduce postoperative pain and hospital stay, and to accelerate return to full activities. We describe our experience with a four-port "lateral" approach in 18 patients. Patients were placed in the lateral decubitus position and the table was flexed to separate the left subcostal margin and iliac crest. The camera port was inserted at the umbilicus and additional ports were placed in the epigastrium and left lower quadrant. After mobilization of the splenic flexure a port was inserted in the left flank below the 12th rib for elevation of the spleen. A 30 degrees laparoscope was used and the splenic vessels were controlled with an endo-GIA and/or clips. The spleens were placed in a bag, morcellated, and extracted through a port site. Eight females and 10 males with a median age of 12.5 years (5-17 years) and weight of 55.5 kg (17-124 kg) underwent splenectomy of idiopathic thrombocytopenia purpora (10), spherocytosis (6), elliptocytosis (1), and Hodgkin's disease (1). The median operating time was 160 min (90-300 min) and median blood loss was 105 ml (5-350 ml). Accessory spleens were removed in four cases. Three patients required extensions of a port site to remove large spleens which could not be placed in a bag. The sole complication was a transient pancreatitis with associated pleural effusion. The median postoperative hospital stay was 2 days (1-11 days) and time to full activities was 8 days (3-25 days). The lateral approach affords excellent visualization of the splenic vessels, pancreas, and accessory spleens. This approach is safe and reliable and is our preferred approach for laparoscopic splenectomy in children.

Adolescent↗
PubMed1996

Intratracheal granuloma formation: a late complication of Marlex mesh splinting for tracheomalacia.

External splinting of the trachea has been used alone or in combination with aortopexy for the treatment of severe tracheomalacia. The authors describe the case of a 12-year-old boy who had a Marlex mesh splint placed because of life-threatening primary tracheomalacia at 6 months of age. He presented at 12 years of age with a 5-month history of shortness of breath on exertion, dry cough, and audible wheeze. Radiological and endoscopic examinations showed near-complete obstruction of the orifice of the right mainstem bronchus by a large polypoid granuloma. Initially the patient was treated with endoscopic resection on two occasions, but the granuloma and bronchial obstruction recurred each time. He underwent a right thoracotomy, which showed that the lower edge of the mesh had eroded through the trachea wall and was acting as a nidus for granuloma formation. After removal of the mesh, the resulting defect at the site of erosion of the trachea was closed with a pericardial patch. The postoperative course was uncomplicated, and the patient remains well 2 years after surgery. External splinting of the trachea has been shown to be effective in the treatment of complicated tracheomalacia, but one must be aware of the potential long-term complications, as demonstrated in this case.

Airway Obstruction↗
PubMed1996

One-stage versus two-stage Soave pull-through for Hirschsprung's disease in the first year of life.

Several investigators have reported good results after a one-stage Soave procedure without a stoma for infants with Hirschsprung's disease. The authors reviewed their concurrent experience with the one- and two-stage approaches, comparing the two groups with respect to rate of complications and clinical outcome. Over a 3-year period, 36 infants with colonic Hirschsprung's disease presenting in the first year of life were treated with a Soave pull-through. Thirteen had a one-stage pull-through, and 23 had a two-stage procedure using an initial stoma. There was no difference with respect to median age at time of diagnosis, median follow-up period, length of aganglionosis, or male:female ratio between the groups. The incidences of major complications such as small bowel obstruction, segmental or acquired aganglionosis, anastomotic leak, and malabsorption were equal between the two groups. However, 13% of the two-stage patients required revision of the stoma. All major complications in the one-stage group were in those who weighed less than 4 kg at the time of surgery. Minor complications such as wound infection, perianal excoriation, and need for repeated dilatation were similar between the groups, but minor stoma-related complications (prolapse or retraction) occurred in 26% of the two-stage infants. When complications were stratified using a more sophisticated scale of severity, no significant difference was found between the groups. The overall complication rate was 1.5 events per patient in the one-stage group and 2.0 events per patient in the two-stage group. This small difference was related to the presence of a stoma in the two-stage group. Overall, 10 of 12 survivors in the one-stage group and 22 of 23 in the two-stage group were doing well, with normal bowel function noted on long-term follow-up (mean period, of 14 and 19 months, respectively). Both one- and two-stage approaches were associated with a significant complication rate, although long-term outcome was excellent in both groups. The higher complication rate in the two-stage group was attributable to the presence of a stoma. For small infants, it may be beneficial to delay the one-stage pull-through until weight exceeds 4 kg.

Anastomosis, Surgical↗
PubMed1993

Lens development in a dominant X-linked congenital cataract of the mouse.

Xcat is a recently identified mouse mutation causing X-linked dominant congenital cataract. The mutation is of particular interest as a possible animal model for the human X-linked cataract syndrome. Using light microscopy, we examined the histological changes of mutant lenses at selected intervals between embryonic (E) day 14 and postnatal (P) day 21. At E14, primary fiber formation completely fills the former lens vesicle in both normal and mutant mice, but in affected animals the primary fibers are irregularly arranged and show small foci of cellular disintegration. Progressive degeneration of primary fibers occurs from E15 to E18 and, during late gestation, secondary lens fibers also begin to degenerate. The lens epithelium and newly differentiated fibers, however, show no evident abnormality. Postnatally, most of the lens substance becomes amorphous; the cataractous process terminates in rupture of the posterior lens capsule by P21. Analysis of crystallin and cytoskeletal proteins of postnatal cataractous lenses revealed no significant abnormalities when compared to normal lenses. The observed sequence of histological changes indicates that the Xcat mutation affects the differentiation of lens fiber cells at some point after their initial elongation.

Animals↗
PubMed1992

Blunt traumatic disruption of the thoracic aorta: a rare injury in children.

Rupture of the thoracic aorta secondary to blunt chest trauma is an exceedingly uncommon injury in pediatric patients. We present a case of blunt traumatic aortic disruption in a 10-year-old child who was successfully managed by primary aortic repair using partial cardiopulmonary bypass. The epidemiology and pathophysiology of this injury, with particular reference to children, is reviewed. The ongoing controversies regarding the diagnosis and operative management of this injury are summarized.

Aorta, Thoracic↗
PubMed1992

The use of indium 111 leukocyte scans in children with inflammatory bowel disease.

Indium 111 leukocyte (WBC) scans have been used in the investigation of inflammatory bowel disease in recent years, but their use in children is not well described. We reviewed our experience with 281 indium 111 scans over an 8-year period in a total of 109 children with inflammatory bowel disease (Crohn's disease 70, ulcerative colitis 39). One hundred twenty-eight indium 111 scans done within 2 weeks of a radiographic contrast study, endoscopic examination, or surgical procedure were evaluated for diagnostic accuracy. Analysis showed that indium 111 scans were accurate when compared with conventional diagnostic tests and operative findings. This noninvasive imaging technique can play a useful role in the management of children with inflammatory bowel disease.

Adolescent↗
PubMed1990

Umbilical fold incision for pyloromyotomy.

A 5-year experience with 100 infants undergoing pyloromyotomy was reviewed. Fifty infants who had a standard right upper quadrant incision were compared with 50 infants in whom an umbilical fold incision was used. The groups did not differ significantly with respect to length of operating time, hospital stay, or intraoperative complications. Wound complications were infrequent and minor in both groups. The umbilical fold incision permits excellent access to the pylorus, while leaving an almost undetectable scar.

Female↗
PubMed1990

Cervical cystic hygroma in the fetus: clinical spectrum and outcome.

Cervical cystic hygroma is thought by most pediatric surgeons to be an isolated, usually resectable lesion with an excellent prognosis. However, prenatal sonography has revealed a high "hidden mortality" among fetuses with this condition, and most perinatologists consider it to be uniformly fatal. In an attempt to resolve these two differing perspectives, we analyzed 29 cases seen at two centers over 4 years. Of 27 fetuses diagnosed before 30 weeks' gestation, only one survived. Twenty-five of the 27 were aborted; severe hydrops was present in 21 of these 25. Two of the 27, both with stigmata of Noonan's syndrome, underwent spontaneous regression during the second trimester: one died at 2 weeks of age, and the other survived. Successful karyotypes were obtained on 17 fetuses: nine were normal, seven were 45X, and one was trisomy 21. Fetuses with abnormal karyotypes had a lower incidence of polyhydramnios (0% v 67%), additional anomalies (12% v 67%), and consanguinity or a history of abnormal pregnancies (0% v 89%). Two fetuses were diagnosed after 30 weeks' gestation. Neither had hydrops, polyhydramnios, associated anomalies, or an abnormal karyotype. One had a completely normal sonogram at 17 weeks' gestation. Both were operated on within the first 4 days of life; one did well without complications, and the other required a permanent tracheostomy because of extensive hypopharyngeal involvement. A cystic hygroma presenting in the fetus has a different natural history and prognosis from one presenting postnatally. The vast majority of fetal cases are diagnosed before 30 weeks' gestation, and present with hydrops or diffuse lymphangiomatosis. The dismal outlook in this group justifies elective termination in most cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Use of the umbilical site for temporary ostomy: review of 47 cases.

We used the umbilical site for temporary colostomy or ileostomy in 47 infants and children. Complications were frequent but were not specifically related to the site of the ostomy. The umbilical site is a convenient site for placement of appliances, and ultimately, after closure, the scar resembles a normal umbilicus and is cosmetically superior to that of an ostomy placed elsewhere.

Child↗
PubMed1983

Event-related potentials recorded during the discrimination of improbable stimuli.

In three separate experiments using auditory stimuli, subjects detected improbable targets in an on-going train of standard stimuli. In experiment I there were two equally improbable target stimuli, one difficult to discriminate from the standard stimuli and one easy to discriminate. Experiment II investigated the effects of discrimination difficulty using four different targets, each equal in probability. Experiment III evaluated the effects of both target discriminability and probability on the target-evoked potentials. The subjects in all three experiments consistently displayed delayed reaction times and higher percentages of misses with the more difficult targets. The amplitude of the N1 wave to target stimuli increased as target discriminability was increased. The latencies of the target-evoked N2 and P3 waves increased and the amplitude of the P3 decreased as target discriminability decreased. The amplitude of the N2 wave increased as the target discrimination became more difficult. The amplitude of the N2 wave elicited by an easy target was enhanced by making the target highly improbable whereas probability did not affect the N2 elicited by a difficult target.

Adolescent↗
PubMed1983

Immunocytochemical localization of the main intrinsic polypeptide (MIP) in ultrathin frozen sections of rat lens.

The in situ distribution of the 26-kdalton Main Intrinsic Polypeptide (MIP or MP 26), a putative gap junction protein in ocular lens fibers, was defined at the electron microscope level using indirect immunoferritin labeling of ultrathin frozen sections of rat lens. MIP was found distributed throughout the plasma membrane of the lens fiber cell, with no apparent distinction between junctional and nonjunctional membrane. MIP was not detectable in the basal or lateral plasma membrane of the lens epithelial cell, including the interepithelial cell gap junctions; nor was MIP detectable in the plasma membrane or gap junctions of the hepatocyte. Previous reports have indicated that the protein composition of the lens fiber cell junction differs from that of the hepatocyte gap junction. The evidence presented here suggests that the composition of the fiber cell junction and plasma membrane is also immunocytochemically distinct from that of its progenitor, the lens epithelial cell.

Animals↗