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Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 595 records · Page 33Linked to original sources
PubMed1989

Mast cells in human odontogenic cysts.

Mast cells have been shown to be present in substantial numbers in both nonkeratinizing and keratinizing odontogenic cysts and could be seen in the connective tissue capsule and the epithelial lining. Within the cyst capsule, mast cells were more prevalent just beneath the epithelium than in deeper areas. This distribution pattern for mast cells is in accord with the histochemical picture for heparin staining in odontogenic cysts. In the non-keratinizing cysts, there appeared to be some trend towards mast cells being associated with increasing inflammation but not in the odontogenic keratocyst. No evidence could be found for distinct mast cell subpopulations in odontogenic cysts. The presence of mast cells in odontogenic cyst could contribute to their pathogenesis in several ways.

Cell Count↗
PubMed1989

Breast carcinoma cellularity and its relation to oestrogen receptor content.

The cellularity of 104 primary breast carcinomata was determined by semiautomated image analysis to allow the relation between cellularity and oestrogen receptor content values to be assessed. The oestrogen receptor content of tumours detected by a steroid binding assay showed no correlation with cellularity, although a possible weak negative correlation was observed between tumour cellularity and oestrogen receptor content detected by enzyme immunoassay. It is concluded that there is no single direct correlation between tumour cellularity and oestrogen receptor content.

Adult↗
PubMed1989

Amplification of airway constriction due to liquid filling of airway interstices.

Luminal epithelial projections formed during bronchoconstriction define interstices in which liquid can collect. Liquid in these interstices could amplify the degree of luminal compromise due to muscular contraction in at least two distinct ways. First, the luminal cross-sectional area is reduced by simple filling of the interstices. Second, if the surface tension (gamma) of the air-liquid interface is positive, the pressure drop across the interface produces an additional inward force that can further constrict the airway. We present a theoretical treatment of these two mechanisms together with data which suggest that both may significantly amplify the luminal narrowing due to airway smooth muscle contraction, particularly in small airways when gamma is high. To qualitatively assess the effects of altered gamma, guinea pig lungs with normal and altered airway liquid lining layers were frozen and studied while fully hydrated by low-temperature scanning electron microscopy. Airway gamma was altered in these animals by intratracheal instillation of 0.5 mg lysoplatelet-activating factor (lyso-PAF). The interstices of normal airways were dry, whereas the interstices of airways with altered surface lining layers were liquid filled. In addition, the surfactant inhibitory properties of lyso-PAF, 2-arachidonyl-PAF, and dipalmitoyl phosphatidylcholine (DPPC) were measured with a pulsating bubble surfactometer, using surfactant TA as the model surfactant. Minimal gamma (gamma min) of surfactant TA alone was 4.0 +/- 0.2 dyn/cm; a 5% mixture of lyso-PAF with surfactant TA resulted in a significantly (P less than 0.02) greater gamma min of 8.8 +/- 1.8 dyn/cm. In contrast, 2-arachidonyl-PAF and DPPC had minimal effects on gamma min of surfactant TA.

Animals↗
PubMed1989

A comparison of cyclosporin versus azathioprine treatment in renal transplants in Edinburgh.

Three year graft survival rates were calculated for 66 patients on cyclosporin and prednisolone immuno-suppression and compared to survival rates for 73 patients on azathioprine and prednisolone. There was a temporary early advantage for the cyclosporin treatment group up to four months post transplant. There was no further significant difference between the two treatment groups with graft survival rate of 81.4% in cyclosporin and 76.7% in azathioprine group at three years post transplant. Fewer of the patients on cyclosporin had acute episodes of rejection. There was no significant difference in serum creatinine or urea at one year, but the haemoglobin level was higher in cyclosporin treated patients. Cyclosporin does not appear to have increased the survival rate significantly in our centre where there is already a high graft survival with azathioprine.

Azathioprine↗
PubMed1989

Plasma exchange for Guillain-Barré syndrome.

The impact of plasma exchange (PE) on the treatment of severe Guillain-Barré syndrome (GBS) was studied by comparing all the 16 patients treated with PE in a London teaching hospital between January 1985 and August 1987, with 64 historical controls drawn from a series of patients observed during a prospective study in South East England in 1983 and 1984. There were no GBS-related deaths in the PE treated group but seven in the historical controls (2P = 0.39). The median duration of ventilation was only 20 days (range 7-64) in the PE group compared with 36 days (range 14-365) in the surviving patients in the control group (2P = 0.06, 95% confidence interval of difference in medians -36 to 0 days). The PE group walked earlier without aid (median 55.5 compared with 86 days, 2P = 0.04, 95% confidence interval of difference in medians -88 to -2 days). Three months after the onset of neuropathy all PE treated patients were able to walk with support or better, whereas 19 of the surviving historical controls were unable to walk even with support (2P = 0.009). The costs of PE were offset by savings in intensive care unit and hospital expenditure.

Adult↗
PubMed1989

Strongyloides stercoralis: is there a canonical migratory route through the host?

It is generally accepted that the skin-penetrating larvae of Strongyloides stercoralis travel from the skin to the intestinal habitat of the adult stage by an obligatory migratory route that includes the blood, lungs, trachea, and upper gastrointestinal tract in sequence (the pulmonary route). It is assumed, furthermore, that following autoinfective invasion of the bowel wall, S. stercoralis larvae follow this same route to return to the small intestine where they mature. We reexamined the parasite's migratory behavior using a canine isolate of S. stercoralis, specific-pathogen-free pups, radiolabeled larvae, and compressed tissue autoradiography. Compartmental analysis of the number of larvae found in the organ sets examined revealed no reason to reject the simple idea that the pulmonary route was just one of several possible pathways to the duodenum. This was true whether the larvae began their journey in the subcutaneous tissue of the inguinal area or in the distal part of the ileum. Direct sampling of the larvae traversing the trachea indicated that the number of larvae reaching the duodenum by way of the presumptive pulmonary route was insufficient to account for the estimated absolute number actually found there.

Animals↗
PubMed1989

Mathematic model for the population biology of rabies in raccoons in the mid-Atlantic states.

A series of coupled differential equations was used to model the temporal dynamics of rabies in raccoons in the mid-Atlantic region of the United States. The model takes explicit account of the development of natural immunity to rabies and was used to evaluate culling and vaccination elimination strategies. For habitats typical of the mid-Atlantic states, and given the assumptions of the model, it was estimated that elimination of rabies in raccoons by culling may involve the annual removal of over 32% of the raccoon population or the yearly vaccination of up to 99% of the susceptible fraction. Assuming a constant marginal cost for both culling and vaccination, the model suggests that, whatever the actual cost of each method, the cheapest strategy will always involve either culling or vaccination alone. A combined strategy of culling and vaccination will be cheaper than culling alone only when the per capita cost of vaccination is around one-fifth or less the per capita cost of culling.

Animals↗
PubMed1989

Non-fatal injuries among motorcyclists treated as in-patients in a general hospital.

In a study of the injury pattern among 198 motorcyclists who sustained road traffic accidents from 1986-1987, it was found that the following body regions, in decreasing order of frequency, were involved: external region (surface or integumentary lesion of any body region) with 285 injuries, extremities and bony pelvis with 118 injuries, head and face with 94 injuries, chest with 10 injuries, abdomen with 3 injuries, and spine with 2 injuries. Despite the extensive use of crash helmets, head injuries were still a common and severe form of injury resulting from traffic accidents, indicating the need for improvement of safety standards of crash helmets. Lower limb injuries, mostly fractures of bones and dislocation of joints, are also amenable to prevention through design of leg protection devices. Injuries to other body regions are difficult to prevent and other measures such as legal and administrative means, should be fully exploited in accident prevention.

Accidents, Traffic↗
PubMed1989

Expression of a muscle-type alpha-actinin cDNA clone in non-muscle cells.

We have previously isolated a chick smooth muscle-type alpha-actinin cDNA clone (C17) from a chick embryo fibroblast cDNA library. As part of an investigation into a possible role for a muscle isoform of alpha-actinin in non-muscle cells, we have cloned C17 into a eucaryotic expression vector, pKCR3, and examined the distribution of the expressed protein in non-muscle, monkey COS cells. We report here that the muscle isoform of chick alpha-actinin encoded by C17, was found in focal contacts and periodically distributed along actin filaments.

Actinin↗
PubMed1988

Defective presentation to class I-restricted cytotoxic T lymphocytes in vaccinia-infected cells is overcome by enhanced degradation of antigen.

Vaccinia infection interferes with the presentation of influenza Haemagglutinin (HA) and Nucleoprotein (NP) to class I-restricted CTL. The inhibitory effect is selective for certain epitopes, and is more profound during the late phase of infection. For influenza A/NT/60/68 NP, the block is present during both early and late phases of infection, and is selective for the COOH-terminal epitope defined by peptide 366-379, having no detectable effect on the presentation of the NH2-terminal epitope 50-63. The presentation of HA is inhibited only during the late phase of vaccinia infection. For both proteins, presentation is partially (NP) or completely (HA) restored by expression of rapidly degraded protein fragments in the vaccinia infected target cell. For HA, deletion of the NH2-terminal signal sequence completely overcomes the block. For NP, either a large NH2-terminal deletion or the construction of a rapidly degraded ubiquitin-NP fusion protein partially restores presentation. These results illustrate the relationship between degradation of viral proteins in the cytoplasm of an infected cell and recognition of epitopes at the cell surface by class I-restricted T cells.

Animals↗
PubMed1988

Failure of hospitals to promote the use of child restraint devices.

Motor vehicle accidents are the leading cause of death in children. In 1977, Tennessee adopted the nation's first law requiring the use of child restraint devices (CRDs), but despite extensive promotional efforts, a majority of young children still travel unrestrained. We surveyed all acute-care hospitals in Tennessee to determine their policies regarding CRDs. Of 109 hospitals with obstetric services, 28 (26%) had a policy calling for discharged newborns to be transported in CRDs; only seven (5%) of 128 pediatric services had such a policy. It is time for hospitals and professional organizations to adopt policies to ensure that the parents of every child discharged from an obstetric or pediatric unit are educated concerning CRD use laws and are able to comply with them. Pediatricians should consider incorporating "discharge in child restraint device" into their routine discharge orders.

Accidents, Traffic↗