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Biomedical subjects

G Malmfors

Publications and source records attributed to G Malmfors.

At least 19 recordsLinked to original sources
PubMed1999

Bladder augmentation with different forms of intestinal grafts: an experimental study in the pig.

OBJECTIVE: To create an experimental animal model to examine changes in bladder volume and histology after bladder augmentation in growing individuals and from the model, evaluate a method using demucosalized intestinal grafts and short-term bladder drainage. MATERIALS AND METHODS: The study comprised 21 piglets: in group 1, seven underwent a sham operation; in group 2, seven piglets underwent bladder augmentation with full-thickness caecum after a major bladder resection; in group 3 seven underwent the same procedure but with demucosalized caecum. The bladder volume and area of the intestinal segment were measured peroperatively and when the animals were killed 2 months later. Bladder specimens were taken for histological examination. RESULTS: The mean preoperative bladder volumes were similar among the groups; in the control group, volumes increased from 58 to 165 mL and in group 2 from 63 to 255 mL, with an increase in area of the intestinal segment from 59 to 138 cm2. In group 3 the volume was unchanged, from 63 to 71 mL, with a decrease in area from 58 to 5 cm2. Control bladders showed normal urothelium with neutral mucins and sialomucins. In group 2, there was metaplasia in the border between urothelium and colonic epithelium, with enhancement of sialo- and sulphomucins. Demucosalization resulted in extensive fibrosis, with a monolayer of urothelial cells showing metaplasia. CONCLUSIONS: The experimental model was successful; the observed changes in bladder volume correlated well with the fate of the intestinal implant, because the bladder resection was major. This is essential, as the bladder remnant has some growth potential. Full-thickness grafts grew faster than the normal bladder. Mechanical demucosalization, including submucosa, results in shrinkage despite short-term drainage. Glandular metaplasia, with production of sialomucins and sulphomucins, occurs at the junction between bladder and colon, irrespective of mucosal removal.

Animals↗
PubMed1999

Pediatric urinary tract reconstruction using intestine.

OBJECTIVE: To analyse the outcome of urinary tract reconstruction in children. MATERIAL AND METHODS: Fifteen children with bladder exstrophy or neurogenic bladder, 4-18 years old, were followed in accordance with a predetermined program for bladder augmentation (13 pat) or continent urinary reservoir (2 pat). The follow-up time was 1.7-6.3 years, median 3.7 years. RESULTS: All were dry, though one case had occasional leaks. Three bladder neck reconstructions, two artificial sphincters, one sling plasty and one fistula closure with subsequent bladder neck injection were required. Bladder volumes were adequate for age at low pressures. Reflux resolved in 12/13 ureters. A boy with preoperative renal insufficiency was transplanted. Total renal function remained otherwise stable despite acidosis in one case and some glomerular impairment in all. Progressive parenchymal lesions were seen in combination with abundant mucus, infections and calculi only. Growth and bowel function was unaffected. Bone mineral density showed overall increase; some low values were not consistent between investigations. CONCLUSIONS: Urinary tract reconstruction in children results in continence and regression of reflux. Growth, bone mineralization and renal function are unimpaired during the first years, but irrigation of the bladder is essential to minimize the risk of urinary tract infection. However, glomerular function might be affected and the possible risk of metabolic complications in later life can only be determined by continuous close monitoring over an extended period of time. ABBREVIATIONS: Voiding cystourethrogram (VCUG), dimercapto-succinic acid (DMSA), Chrome51-Ethylenediaminetetraacetic acid (Cr-EDTA), single photon absorption (SPA), bone mineral content (BMC), bone mineral density (BMD), dual photon x-ray absorption (DEXA), glomerular filtration rate (GFR), urinary tract infection (UTI), immunoglobulin G (IgG), clean intermittent catheterization (CIC) and subureteral teflon injection (STING).

Adolescent↗
PubMed1998

Balloon dilatation of oesophageal strictures in children.

During the last ten years balloon dilatation has become increasingly frequent in the therapy of oesophageal strictures, both for diagnosis and treatment. From 1983 to 1994, balloon catheterization was performed in 36 children (oesophageal atresia 28, tracheo-oesophageal fistula 3, congenital stenosis 1, acquired oesophageal stricture subsequent to gastro-oesophageal reflux 1, to caustic ingestion 3). Age at treatment varied from 2 weeks to 15 years. Thirty-nine (3 double) strictures were dilated a total of 171 times. Balloon dilatation was successful in 31 cases (79%). In two children therapy was changed to conventional bouginage and six strictures were resected. Advantages of the method may include that forces are exerted radially and that the procedure may be performed under better control since fluoroscopy is used.

Adolescent↗
PubMed1997

Increased parental participation in a paediatric surgical day-care unit.

Day care is currently a common way of providing treatment for minor and average paediatric surgical procedures. The purpose of this study was to assess possible benefits of increasing parental involvement in the care of operated children in a day-care surgery unit. By giving parents information and education about post-operative care, the goal was to facilitate recovery and minimize time spent in hospital. Results show that parents in the intervention group were well prepared to assume a greater part of the care of their children. Children in the intervention group appeared to have less pain and fewer children vomited post-operatively than children in the control group.

Adolescent↗
PubMed1996

Bladder exstrophy in Sweden--a long-term follow-up study.

A retrospective review of all new cases of bladder exstrophy in Sweden in 1970 through 1989 is presented. The aim was to evaluate management of the malformation in Sweden and possibly identify factors that might improve the outlook. The incidence was 1:33,500 births. Records were reviewed of the 61 children (37 males and 24 females) treated at Sweden's four specialist centers of pediatric surgery. There was one perinatal death. Primary management was mainly early bladder closure (within 72 hours), late closure or perinatal urinary diversion. Subsequent measures included augmentation cystoplasty, bladder neck reconstruction, provision of continent urinary reservoir and penile reconstruction. The follow-up time was 4-19 years. In 15 cases renal scarring developed, though with impairment of total function in only three. Ten patients achieved continence, defined as 3-hour dry intervals, of whom four had urinary reservoirs with continent stoma. Urinary tract infections were recorded during follow-up in 43% of the surviving patients, though the true incidence of infection presumably was higher. To improve management of bladder exstrophy in sparsely populated Sweden, a nation-wide strategy of ongoing interhospital collaboration has been adopted. Results will be continuously presented.

Adolescent↗
PubMed1994

Chromogranin A and B in neuronal elements in Hirschsprung's disease: an immunocytochemical and radioimmunoassay study.

Chromogranin A and B (CAB) occur in several peptide hormone-producing cells and in neurons of the brain. The aim of the present study was to investigate the possible neuronal localization of these chromogranins in the ganglionic and aganglionic bowel in Hirschsprung's disease by immunocytochemistry and radioimmunoassay, using antibodies recognizing either chromogranin A or both chromogranin A and B. Further, the coexistence of chromogranins and other neuronal constituents was studied. CAB were found in nerve fibers and occasionally in nerve cell bodies of submucous and myenteric ganglia in the ganglionic bowel, indicating that at least a population of chromogranin-immunoreactive nerve fibers is intrinsic in origin. CAB-immunoreactive fibers were numerous in the muscle layers of the aganglionic segment. These fibers contained tyrosine hydroxylase (TH), which indicates that they are adrenergic, in both ganglionic and aganglionic bowel. In the muscle layers of aganglionic (but not ganglionic) bowel, chromogranin A coexisted with galanin, neuropeptide Y (NPY), and vasoactive intestinal peptide (VIP). The concentration of CAB in smooth muscle specimens was higher in the aganglionic bowel than in the ganglionic bowel. Thus, chromogranins are present in the human enteric gut hyperinnervating the aganglionic bowel of Hirschsprung's disease.

Chromogranin A↗
PubMed1993

Peptide-containing neurons remain unaffected after intestinal autotransplantation: an experimental study in the piglet.

The gut is richly supplied with peptide-containing nervous elements. In the present immunocytochemical study the origin, occurrence and topographical distribution of nerves containing vasoactive intestinal polypeptide (VIP), enkephalin, substance P (SP), somatostatin, neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), gastrin-releasing peptide (GRP) and galanin were investigated in the porcine small intestine. In order to study the origin (extrinsic or intrinsic) of the nerve fibers, specimens from autotransplanted and extrinsically denervated jejunum were examined. Furthermore, possible changes in the distribution of intrinsic neurons after extrinsic denervation were studied. In the control jejunum each nerve fiber population had its own characteristic topographic distribution. There was no overt difference in distribution pattern of peptide-containing nerve fibers and cell bodies between the transplanted and the control segment except that NPY-, SP- and CGRP-containing nerve fibers disappeared around blood vessels. Thus VIP-, somatostatin-, GRP-, enkephalin- and galanin-containing nerve fibers were visibly unchanged in the transplanted segment. The results support the view that the peptide-containing nerve fibers are mainly intrinsic in origin except the NPY-, SP- or CGRP-containing perivascular nerve fibers which are extrinsic to the gut wall. In addition, the results of the present study suggest that transplantation and extrinsic denervation have no major effect on the distribution pattern of the intrinsic neuronal systems.

Anastomosis, Surgical↗
PubMed1992

A novel neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP), in human intestine: evidence for reduced content in Hirschsprung's disease.

A novel neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP), exhibits sequence homology with vasoactive intestinal polypeptide (VIP) and occurs in the mammalian brain, lung and gut. The distribution of PACAP in ganglionic and aganglionic portions of the large intestine of patients with Hirschsprung's disease was examined by immunohistochemistry and radioimmunoassay. PACAP-immunoreactive nerve fibers were distributed in all layers of the ganglionic and aganglionic segments of the intestine, although they were less numerous in the latter, and PACAP-immunoreactive nerve cell bodies were seen in the ganglionic portion of the intestine. The concentration of immunoreactive PACAP was lower in the aganglionic than in the ganglionic segment of the intestinal wall. PACAP and VIP were found to coexist in both ganglionic and aganglionic segments of the intestine. Apparently, PACAP participates in the regulation of gut motility. The scarcer PACAP innervation of the aganglionic segment may contribute to the defect in intestinal relaxation seen in patients with Hirschsprung's disease.

Ganglia↗
PubMed1991

NPY hyperinnervation in Hirschsprung's disease: both adrenergic and nonadrenergic fibers contribute.

In Hirschsprung's disease, the aganglionic bowel is characterized by an absence of ganglion cells and an increased number of adrenergic and presumed cholinergic nerve fibers. In addition, a severe derangement of peptide-containing nerve fibers is encountered including a hyperinnervation of neuropeptide Y (NPY)-containing fibers. Using immunochemical and immunocytochemical methods, we examined the nature of the NPY-containing nerve fibers contributing to the hyperinnervation. The concentration of NPY was markedly increased in the aganglionic segment. Coexistence of NPY, vasoactive intestinal peptide (VIP), and the adrenergic enzyme tyrosine hydroxylase (TH) showed small populations of nerve fibers containing NPY/TH, NPY/VIP, or TH alone in ganglionic intestine. Numerous nerve fibers stored VIP but lacked NPY. These fibers did not contain TH, indicating that all VIP-containing fibers are nonadrenergic. In the aganglionic intestine there was a marked increase in the number of nerve fibers storing NPY/TH and NPY/VIP, whereas the fibers storing VIP alone were reduced in number. A small number of nerve fibers storing NPY alone occurred in the hypertrophic nerve bundles. NPY/VIP-containing nerve fibers were particularly numerous in the mucosa in aganglionic intestine, which may be of interest in the diagnosis of Hirschsprung's disease allowing the use of mucosal biopsy specimens. Thus, the proliferating NPY-containing nerve fibers in the aganglionic intestine seem to comprise three different populations, one adrenergic and two nonadrenergic, one of which contains in addition VIP.

Adrenergic Fibers↗
PubMed1989

Port-A-Cath in children during long-term chemotherapy: complications and outcome.

Complications related to Port-A-Cath were studied prospectively during a period of 32 months in 31 patients, aged 1-18 years, with leukemias and solid tumors. There were 34 Port-A-Cath inserted, and the cumulative time for these catheters kept in place was 5899 days. No complications occurred in 18 patients (19 catheters) kept in place for a cumulative time of 3998 days with an average duration of 210 days (12-550 days). In 13 patients (15 catheters) there were 14 events of systemic infections; seven events were treated successfully with antibiotics, four events necessitated the extraction of the catheter (in one patient a combination of systemic and local infection), and in three events the catheters were kept unused, as the patients were in terminal stages. Nonsystemic complications occurred with five catheters; two local infections, two obstructions (catheters removed), and one local bleeding (catheter kept unused). Appropriate antimicrobial treatment of systemic infections enables the immunocompromised child to keep the Port-A-Cath in place for a long time.

Adolescent↗
PubMed1988

Neuropeptide Y, calcitonin gene-related peptide, and galanin in Hirschsprung's disease: an immunocytochemical study.

The aganglionic intestinal segment in Hirschsprung's disease is known to contain a reduced number of nerve fibers storing vasoactive intestinal peptide (VIP), substance P (SP), enkephalin, and gastrin-releasing peptide (GRP). In this study, nerves containing three newly described neuropeptides: neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), and galanin were examined using immunocytochemistry. Nerve fibers displaying NPY immunoreactivity were found to be more frequent in the aganglionic than in nonafflicted ganglionic intestine. Nerve fibers storing CGRP and galanin on the other hand were roughly equally frequent but the distribution pattern differed in that the bulk of fibers in the aganglionic intestine was localized to large nerve trunks not seen in the ganglionic segment. The functional significance of these changes has yet to be defined.

Calcitonin↗
PubMed1987

Ontogeny of peptide-containing neurons in human gut--an immunocytochemical study.

Neurons containing enkephalin, substance P (SP), vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), galanin, calcitonin gene-related peptide (CGRP), peptide histidine isoleucine (PHI) or gastrin-releasing peptide (GRP) are known to occur in the human intestinal tract. The knowledge of the ontogeny of these neurones is, however, limited. Intestinal specimens from 24 human foetuses with gestational ages varying between 8 and 40 weeks were examined by immunocytochemistry. No peptide-containing neurones could be detected before the 14th week of gestation after which a rapid development was seen. Generally, peptide immunoreactivity was first noted in the myenteric ganglia and somewhat later in the other layers of the intestinal wall. There was no major difference between the peptides studied or between different parts of the intestinal tract with respect to time of appearance.

Calcitonin Gene-Related Peptide↗
PubMed1987

Hirschsprung's disease: a comparison of the nervous control of ganglionic and aganglionic smooth muscle in vitro.

Specimens from aganglionic (constricted) and ganglionic (dilated) gut were obtained from nine patients with Hirschsprung's disease. Transmural nerve stimulation of ganglionic smooth muscle in vitro evoked an initial relaxation followed by a contraction. This contraction was reduced but not abolished by atropine and it was further reduced by substance P antagonists. Guanethidine did not affect the electrically evoked responses. In aganglionic smooth muscle, an atropine-sensitive contraction but no initial relaxation was registered. Tetrodotoxin abolished all responses to electrical stimulation in both ganglionic and aganglionic specimens. Application of carbachol or substance P produced contraction and the adrenergic agonist isoprenaline or vasoactive intestinal peptide produced relaxation in ganglionic as well as aganglionic specimens. Two other gut neuropeptides, neuropeptide Y and galanin, were without effect. The results do not indicate a different receptor set up in ganglionic v aganglionic gut. The results are compatible with a lack of noncholinergic nonadrenergic inhibitory neurons in the aganglionic gut.

Child↗
PubMed1986

Reconstruction of the thoracic esophagus using autotransplanted small intestine--an experimental study in the piglet.

An experimental method is reported for bridging defects of the thoracic esophagus, using a free jejunal graft connected to the aorta by microvascular anastomoses. The advantages of this method are that defects are bridged by vital and well-vascularized tissue and that only short bowel segments are required. Drawbacks seen in animal experiments are a relatively difficult operative technique and a high complication rate. This high complication rate might be lowered in infants under intensive-care conditions.

Animals↗
PubMed1986

Peptidergic innervation in infantile hypertrophic pyloric stenosis.

The gastrointestinal tract harbors several populations of peptide containing nerve fibers. Among the gut neuropeptides are vasoactive intestinal peptide (VIP), substance P, enkephalin, and gastrin releasing peptide (GRP). We have examined specimens from five patients with pyloric stenosis and from five controls immunocytochemically with respect to the density of nerve fibers containing VIP, substance P, enkephalin, or GRP. In the control specimens VIP and enkephalin fibers were fairly numerous, whereas substance P and GRP fibers were few. In the pyloric stenosis patients the density of VIP fibers and enkephalin fibers was reduced in the smooth muscle. In the myenteric ganglia there was no such reduction. Substance P and GRP fibers were rare as in controls. The results indicate a reduction of VIP and enkephalin fibers in smooth muscle in pyloric stenosis patients and may be interpreted to support the view that an impaired neuronal function is involved in the pathophysiology of pyloric stenosis.

Enkephalins↗
PubMed1986

Circumcision for phimosis--indications and results.

A follow-up study including all boys (n = 117) operated with circumcision for phimosis during 1976 was performed. Most patients were operated on an outpatient basis. Early complications like bleeding or infection were few and mild. In 13 cases there was a postoperative stricture of the urethral orifice which had to be widened. Five patients had complaints about the cosmetic result. Eight boys expressed shyness and unwillingness to undress in school gym. In no instance were there any signs of a more serious psychological disorder. The operative indications are discussed and it is concluded that worried parents of boys with phimosis can be safely advised to have their boys circumcised if the prepuce is scarred or there has been recurrent balanitis, or if the boy has reached school age and the foreskin is still unretractable.

Child↗