Search PubMed⌕ Search

Biomedical subjects

G M Lees

Publications and source records attributed to G M Lees.

9 recordsLinked to original sources
PubMed1992

Complex correlations between the morphology, electrophysiology and peptide immunohistochemistry of guinea-pig enteric neurones.

Neuroanatomical, electrophysiological and immunohistochemical techniques were used to describe correlations between soma morphology and electrophysiological properties in two groups of guinea-pig enteric neurones posing particular challenges. Lucifer Yellow-staining of 542 myenteric plexus neurones of duodenum revealed a great diversity of neuronal morphology. The distribution was: Dogiel Type I 27%, Dogiel Type II 54%, Stach Type IV 9%; 10% were unclassified. Correlations were sought in 59 of these cells between morphology and electrophysiological properties but no particular association was recognised. Dynorphin A(1-8)-like immunoreactivity (Dyn A(1-8)-IR) was found in up to 90% of identified submucous neurones of guinea-pig ileum. Of 62 S-neurones, 41 showed 'weak' and 19 had 'intense' Dyn A (1-8)-IR. There was no evidence of Dyn A(1-8)-IR in 2 S-neurones, nor in 8/8 AH-neurones. As for 11/16 vasoactive intestinal peptide- (VIP-) IR neurones, there was a strong correlation between the presence of 'weak' Dyn A(1-8)-IR and the occurrence of inhibitory (IPSPs) and slow excitatory synaptic potentials (EPSPs) (13/16 cells tested), which were never observed in neurones with 'intense' Dyn A(1-8)-IR (16/16) or neuropeptide Y (NPY)-IR (8/8). Similarly, 7/7 neurones with 'weak' Dyn A(1-8)-IR, but not those (7/7) with 'intense' Dyn A(1-8)-IR, hyperpolarised or showed a conductance change to noradrenaline. It was concluded that dynorphin A(1-8)-like-IR was contained in two populations of submucous neurone that are anatomically, immunohistochemically, electrophysiologically and pharmacologically distinct and closely related to those containing VIP and NPY. Furthermore, as in the myenteric plexus throughout the small intestine, opioid peptides are not expressed in Dogiel Type II cells.

Animals↗
PubMed1992

Choledochal cysts: a retrospective review of 28 patients and a review of the literature.

Retained choledochal cysts have been associated with recurrent cholangitis, portal hypertension and malignant lesions of the biliary tract. The authors reviewed the cases of 23 females and 5 males who had congenital cystic dilatation of the biliary tree; 26 were seen primarily and 2 were referred because of complications from previous surgery. Patient age at presentation ranged from 6 weeks to 46 years. The presenting complaints in 25 patients were pain or jaundice, or both; the classic triad of pain, jaundice and an abdominal mass was present in only 3 patients. Primary cyst excision was performed in 11 patients. Internal drainage procedures were performed in 12 patients, external drainage procedures in 3 patients and no direct operative procedure in 2 patients. Follow-up ranged from 1 to 20 years. Nine of 11 patients with primary excision were asymptomatic; 2 had recurrent cholangitis and required treatment for bile duct stricture. Five patients with retained cysts were asymptomatic. Recurrent cholangitis occurred in seven patients. Six patients required at least one reoperation, but only two had secondary cyst excision. The long-term complication rate for patients with retained cysts was 66.7% and for those with primary excision was 18%. The findings of this study support the current recommendation of primary excision of choledochal cysts. Symptomatic patients with retained cysts should have secondary cyst excision. Asymptomatic patients with retained cysts are at risk for malignancy and should undergo lifelong periodic radiologic examinations and liver-function testing.

Adolescent↗
PubMed1991

Inflammatory pseudotumours of the lung: two cases and a review.

A discrete pulmonary mass lesion has different implications in children and in adults. Although infectious, congenital and metastatic etiologies are part of the differential diagnosis, inflammatory pseudotumour of the lung, or plasma cell granuloma, has emerged as the most common entity. The authors describe two patients with this poorly understood lesion and review the current state of knowledge. Both patients were young (4 and 5 years) and had recurrent lower respiratory tract infections; one patient was asthmatic. Both had persistent cough, and discrete lung lesions were apparent radiologically. Both children were treated by thoracotomy and excision of the tumour. There were no operative complications, and the convalescent period was uncomplicated. There were no signs of recurrence at follow-up 1 and 2 years postoperatively. This lesion is almost always benign, but aggressive behaviour has been documented. The authors recommend prompt conservative surgical excision.

Child, Preschool↗
PubMed1990

Monochorionic diamniotic minimally conjoined twins: a case report.

We present the second case of monochorionic diamniotic (MC/DA) conjoined twins. There was minimal conjunction, which was predominantly extrafetal and confined to the periumbilical ventral region. The omphalopagus twins, attached to a single forked umbilical cord, were connected by a shared umbilical hernia containing the ileum of twin B. The only visceral conjunction, located just within the belly of twin A, was midileal with the 2 separate ileums converging toward a short segment of shared muscularis propria and of side-to-side fistulization. Gastrointestinal and musculoskeletal anomalies were present in both twins with severe amyoplasia and arthrogryposis multiplex in twin A. Possible mechanisms underlying this unusual form of MZ twinning are discussed.

Abnormalities, Multiple↗
PubMed1990

The physiology of adaptation to small bowel resection in the pig: an integrated study of morphological and functional changes.

This study examined the adaptive response to extensive small intestinal resection in the juvenile domestic pig. Control animals underwent an ileal transection with end-to-end anastomosis, whereas resected pigs had a resection of the mid-75% of the total small bowel length. Animals were followed for 16 weeks. Resected animals gained less weight than controls, with no significant difference in feed intake per unit animal weight. In vivo fat, protein, carbohydrate, and total energy absorption were reduced in resected animals. Resected pigs had increased in vitro passive ileal uptake of fatty acids, cholesterol, and L-glucose, but no change in active D-glucose uptake. Microscopic morphology was altered, with an increase in the size of villi, a decrease in villous density, and no net change in mucosal surface area per unit of serosal surface area. Gross bowel length and diameter increased proportionately more in the resected than the control groups. This study demonstrated that massive resection results in a significant change in nutritional status in the growing pig. Functional and morphological changes occur, demonstrating intestinal adaptation. These findings suggest that this model would be suitable for the study of therapeutic modalities for the short-bowel syndrome in humans.

Animals↗
PubMed1979

Elastin and granulation tissue.

The contraction of granulation tissue is an important factor in wound healing. The tract of an abdominal drainage tube closes at the rate of 1 mm/h once the tube is removed. Specialized myofibroblasts are generally believed to be responsible for this process and the presence of elastin in granulation tissue has been debated for many years. A 3-mm polyethylene tube was inserted through the left lobe of the liver in 41 rats. A tube of granulation tissue formed around the plastic. This granulation tissue was isolated, after periods ranging from 8 to 20 days, by removing the left lobe of the liver and scraping away the surrounding liver tissue. Biochemical assay for elastin revealed that normal hepatic tissue does not contain any detectable amount of elastin. All 41 samples of granulation tissue contained elastin with a mean value of 8.5 X 10(-6) g of elastin per milligram of tissue. Normal rat aorta contains 31.4 X 10(-6) g of elastin per milligram of tissue. These tubes of granulation tissue were histologically normal and the presence of elastin was recognized using elastin stains. The exact role of elastin in granulation tissue is uncertain but this experiment clearly demonstrates its generation and presence there.

Animals↗
PubMed1976

Investigation of occurrence of tolerance to bronchodilator drugs in chronically pretreated guinea-pigs.

1 The actions of sympathomimetic amines on isolated preparations of atria, trachea and ileum were studied in vitro in guinea-pigs, which had been pretreated for 5 or 12 days, by subcutaneous injection, with adrenaline (5 mug/kg), salbutamol (0.5 mug/kg), salbutamol (0.5 mug/kg), methoxamine (250 mug/kg) or saline (0.9% w/V NaCl solution). 2 In the trachea, a decrease in sensitivity (tolerance) to the relaxant effect of adrenaline was induced by pretreatment, for 12 but not for 5 days, with adrenaline. In these animals, cross-tolerance to isoprenaline or salbutamol was not observed. Tolerance to the relaxant actions of adrenaline isoprenaline or salbutamol was not observed after pretreatment with salbutamol. 3 In the trachea, pretreatment with methoxamine or adrenaline for 12 days did not change the sensitivity to the alpha-adrenoceptor-mediated contractor action of methoxamine. 4 In the atria from those guinea-pigs pretreated with adrenaline or salbutamol, there was no reduced sensitivity to the beta-adrenoceptor agonist actions of adrenaline, isoprenaline or salbutamol. In animals pretreated with methoxamine or adrenaline, there was no observable tolerance or cross tolerance to methoxamine with respect to its alpha-adrenoceptor-mediated positive inotropic action in the atria and no unequivocal evidence of a reduced sensitivity to that action of adrenaline. 5 It was confirmed that the twitch-like contractions of the longitudinal muscle of the electrically stimulated ileum were inhibited by sympatomimetic amines acting on alpha- and beta-adrenoceptors. There was no reduced sensitivity to the inhibitory actions of noradrenaline or isoprenaline on the twitch of ileum isolated from animals pretreated with adrenaline, salbutamol or methoxamine for 5 or 12 days. 6 From our results on these three preparations from the same animals, it is concluded that generalizations regarding changes in sensitivity to sympathomimetic amines following their prolonged administration should not be made in any one species.

Animals↗