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Biomedical subjects

P Banks

Publications and source records attributed to P Banks.

At least 55 records · Page 3Linked to original sources
PubMed1991

The regulation of actin polymerization in differentiating U937 cells correlates with increased membrane levels of the pertussis-toxin-sensitive G-protein Gi2.

Undifferentiated U937 cells appear to lack a capacity of increase cellular F-actin. However, electropermeabilized cells gain the ability to respond in this way to a guanine nucleotide analogue, guanosine 5'-[gamma-thio]trisphosphate (GTP[S]) after 1 h of treatment with dibutyryl cyclic AMP (db-cAMP). The results reported here show that the levels of membrane association of the G-protein Gi2 alpha increase with a time course identical with that of the GTP[S]-sensitivity of electropermeabilized cells. These results suggest that Gi2 alpha may be involved in the signal-transduction pathway leading to actin polymerization in db-cAMP-differentiated U937 cells.

Actins↗
PubMed1991

The role of protein kinase C activation and inositol phosphate production in the regulation of cell-surface expression of Mac-1 by complement fragment C5a.

The adhesion of leukocytes to endothelial and other cell types is an essential part of the acute inflammatory response. One means by which adherence can be increased is by activation of the CD11/CD18 family of leukocyte glycoproteins. Chemotactic peptides, lipid mediators, phorbol esters and tumour necrosis factor are all able to increase the cell surface expression of one member of this family, CD11b/CD18 or Mac-1, by an unknown signal transduction mechanism. In this report, regulation of Mac-1 expression by C5a is shown to be independent of protein kinase C (PK-C) activation. The inhibitor of PK-C, H-7, has no effect on the action of C5a and only a slight effect on phorbol ester-induced up- and down-regulation of Mac-1, at a concentration that inhibits superoxide production in response to both factors by 40%. Inositol phospholipid hydrolysis, an important pathway leading to PK-C activation, and the transient increases in cytosolic Ca2+ associated with inositol phosphate production, are also shown to be not essential processes in C5a-stimulation of Mac-1 expression.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

A ganglion of the temporomandibular joint: a case report.

Ganglion cysts of the TMJ are rare and accurate preoperative diagnosis is not usually made, although theoretically this might be possible with arthrography. Treatment of the condition is surgical but, if a positive diagnosis can be made, a period of conservative management could be attempted if the cyst is not excessively painful or surgery is contraindicated for any reason.

Female↗
PubMed1991

Evidence for the involvement of multiple signalling pathways in C5a-induced actin polymerization and nucleation in human monocyte-like cells.

The signal transduction mechanisms involved in complement fragment C5a-induced recruitment of actin to the cytoskeleton have been investigated using U-937 cells differentiated by exposure to dibutyryl cyclic AMP. Two parameters of cytoskeletal activation were compared: F-actin formation and nucleation of polymerization of pyrenyl-actin in whole cell lysates. The dose dependency of these responses to C5a was clearly different to that observed for [3H]inositol phosphate formation and also markedly different from that observed for the production of reactive oxygen intermediates (ROI). Further evidence to dissociate inositol lipid hydrolysis from these cytoskeletal responses was obtained by treating cells with neomycin, phorbol myristate acetate and pertussis toxin and by modulating the levels of intracellular Ca2+ using quin 2. Inhibition of [3H]inositol phosphate and ROI production was not correlated with effects on actin recruitment or nucleation. In addition, these agents had differing effects on F-actin formation and nucleation activity. The results show that the production of inositol phosphates is not required for stimulating either F-actin formation or nucleation activity and also that ligand-induced polymerization of actin depends primarily upon an increase in the availability of G-actin rather than nucleation sites. These cytoskeletal responses are apparently controlled by different signalling pathways which diverge at an early stage.

Actins↗
PubMed1990

Spindle cell neoplasms of lymph nodes of probable reticulum cell lineage. True reticulum cell sarcoma?

Primary spindle cell neoplasms involving hematolymphoid organs are extremely rare. We present four cases of spindle cell neoplasms of unusual phenotype arising within lymph nodes. Two of the four cases showed morphologic and immunophenotypic features suggestive of interdigitating reticulum cell lineage; these cases expressed several macrophage antigens and S-100 protein but not CD1. The other two cases showed evidence suggestive of dendritic reticulum cell lineage. Both cases expressed HLA-DR, several macrophage antigens, complement receptors C3b and C3d; one case expressed R4/23; both showed the presence of desmosomes on ultrastructural examination. A germline configuration for the immunoglobulin heavy chain and beta-T--cell receptor genes was detected in all four cases. Of the two patients in the first group, one had local recurrence of tumor; the other died of widespread metastases. Of the two patients in the second group, both are alive and well at 12 and 27 months follow-up, respectively.

Adult↗
PubMed1989

Surgical treatment of mandibular retrusion by a post-condylar cartilage graft.

Mandibular advance in 22 retrognathic adolescent patients (median age 15.7 months) was carried out using a post-condylar graft of lyophilised cartilage. The post-surgical changes were evaluated by a computer-aided digitisation programme after a mean follow-up period of 23 months. Horizontal relapse of the anterior mandible was 3.45% overall, with a corresponding increase of 6.13% in the vertical height of the anterior face. Significant individual relapse in four of the cases resulted from condylar remodelling. Changes at the angle of the mandible and rotational changes of the mandibular plane were also measured.

Adolescent↗
PubMed1989

Freeze-fracture investigation of the red pulp of human spleen.

This study concerns the morphology of the human spleen in freeze-fracture replicas and compares this with the findings in ultrathin sections. The material investigated consisted of two spleens resected at gastrectomy and one resected because of splenomegaly in a case of hairy cell leukaemia. The current concepts concerning the ultrastructure of the spleen were generally confirmed with the freeze-fracture technique. The sinus walls were found, as expected, to consist of closely fitting endothelial cells, which were identifiable in freeze-fracture replicas by numerous caveolae of the cell membrane. Contrary to the opinion upheld in the literature, the sinus endothelial cells were occasionally found to be connected by desmosomes or maculae adhaerentes. Corresponding to the finding of desmosomes in ultrathin sections, focal collections of intramembranous particles were observed in freeze-fracture replicas and a positive immunohistochemical reaction for desmoplakin in the sinuses was found at the light microscopic level. The view generally held in the literature that sinus endothelial cells can exhibit tight junctions was not confirmed. However, such junctions were found between vascular endothelial cells. The ring fibres of the sinuses, which are closely connected to the sinus endothelial cells through contractile fibres, apparently have various functions. Firstly, they contribute towards maintaining mechanical stability. Secondly, they represent basement membranes through which exchange occurs between the sinus endothelial cells and their surroundings. This is indicated by the caveolae and vesicles that are often found here in large numbers and in focal collections. Hairy cells exhibit no features in freeze-fracture replicas to suggest a cytogenetic relationship to interdigitating reticulum cells.

Basement Membrane↗
PubMed1989

A retrospective study of the stability of midface osteotomies in cleft lip and palate patients.

Relapse following midface osteotomies in cleft lip and palate patients was investigated in a retrospective study. The amount of surgical movement and subsequent relapse was measured using a computer aided digitisation programme with reference to the cranial base. The mean maxillary surgical advance was 5.09 mm horizontally and 5.70 mm vertically. After a mean follow up period of 22 months the mean relapse of the anterior maxilla was 0.90 mm (17%) horizontally and 1.55 mm (27.2%) vertically. Preliminary indications are that direct skeletal fixation of the maxilla by bone plates results in less relapse than when cranio-maxillary fixation is employed.

Adult↗
PubMed1988

Recruitment of actin to the cytoskeletons of human monocyte-like cells activated by complement fragment C5a. Is protein kinase C involved?

U-937 cells differentiated by exposure to dibutyryl cyclic AMP respond to complement fragment C5a with a marked increase in cytoskeletal F-actin, which can be detected by fluorescence-activated cell sorting (f.a.c.s.) analysis of their rhodamine phalloidin-stained cytoskeletons. The C5a-induced increase in F-actin content can be prevented by prior exposure of the cells to cytochalasin B and pertussis toxin. It is insensitive to removal of extra cellular Ca2+, to cholera toxin or to neomycin. Phorbol myristate acetate (PMA), an activator of protein kinase C, does not induce actin polymerization in the differentiated cells. Both C5a and PMA stimulate superoxide production. The action of C5a on superoxide formation is also inhibited by neomycin, a phospholipase inhibitor. These results suggest that the cytoskeletal response to C5a requires activation of a G protein, but probably does not involve phospholipase C and protein kinase C, and is not highly dependent on the availability of Ca2+. Phospholipase C and kinase C may, however, be components of the pathway leading from C5a binding to superoxide production.

Actins↗
PubMed1987

Use of the working formulation for non-Hodgkin's lymphoma in epidemiologic studies: agreement between reported diagnoses and a panel of experienced pathologists.

Independent review of slides of 668 cases of non-Hodgkin's lymphoma (NHL) by a panel of 4 experienced pathologists using the Working Formulation (WF) allowed determination of the agreement between reported diagnoses and panel review of slides. The panel agreed with the reported diagnosis of NHL in 93% of cases, but with the NHL subtype in only 55% of cases overall. The ability of the panelists to agree among themselves, however, was only slightly better than the panelists' agreement with the reported diagnosis (60% vs. 54%, respectively). Agreement of the panel with the reported subtype diagnosis varied from 14% to over 90%. The best agreement was with small lymphocytic lymphoma and follicular subtypes. Conclusions from this study are: 1) The WF functions well as common language for translation and comparison of diagnoses of subtypes of NHL. 2) Relative to time and cost involved, panel review using only light microscopy may not be useful in epidemiologic studies of NHL. 3) Small lymphocytic and follicular subtypes of NHL can be used more confidently in epidemiologic studies than can other subtypes whether the subtyping is done from abstracted reports or by panel review.

Humans↗
PubMed1986

Orthognathic surgery for the adult patient with cleft lip and palate.

A review of the surgical management of adult patients with cleft lip and palate is presented together with the anatomical relationship to surgical procedures. There is still a much higher tendency to relapse after maxillary osteotomy in cleft patients compared to non-cleft patients. However relapse can be reduced by prolonged cranio-maxillary fixation or by direct skeleton fixation with bone plates. Techniques which mobilise the badly scarred palate and avoid dragging it forward with the osteotomy also reduces relapse.

Adult↗
PubMed1985

The postcondylar cartilage graft--an evaluation of an alternative surgical method for the treatment of retrognathia.

Postcondylar cartilage grafts were used for 6 years to advance the mandible surgically in adolescent patients with retrognathia. Thirty-seven subjects were treated; of these, 30 were followed for more than 1 year and have been analyzed. Relapse occurred in 9, caused mainly by displacement of the graft. In the stable group temporomandibular joint changes were studied. Progressive calcification of the graft occurred and a normally functioning joint was established in the advanced position. Improvements in surgical technique--in particular, the fixation of the graft--produced consistent stability in the later cases.

Adolescent↗
PubMed1985

Enzyme inhibition by steroid anaesthetic agents derived from progesterone.

The anaesthetic potency of steroids related by metabolism to progesterone shows marked variation with small changes in structure. In addition, the same group of substances have varying abilities to inhibit bacterial luciferase competitively, although there is no correlation between anaesthetic and inhibition potency. The data do, however, show that closely related hydrophobic steroids are able to interfere with the catalytic activity of an enzyme selectively and, by inference, suggest that differences in anaesthetic potency could be a consequence of selective differences in ability to interact with a target protein.

5-alpha-Dihydroprogesterone↗