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Biomedical subjects

B Sutton

Publications and source records attributed to B Sutton.

At least 19 recordsLinked to original sources
PubMed2006

Massive intraoperative pulmonary embolism: it may not be as bad as it looks....

An elderly patient suffered a cardiac arrest while undergoing repair of a pathological femoral fracture. Intraoperative transoesophageal echocardiography demonstrated massive pulmonary embolism. Pulmonary embolectomy was considered inappropriate in view of her underlying terminal disease, so a decision was made to withdraw all further supportive measures. Despite this, the patient's haemodynamics improved spontaneously. The embolic material was presumed to be bone marrow fat. Fat may traverse the pulmonary circulation; hence the clinical consequences (and management implications) of massive intraoperative pulmonary embolism may vary, depending on the composition of the embolic material. As there are no reliable means of determining the composition of embolic material intraoperatively, the clinical suspicion of fat embolism poses a management dilemma. Should these cases be managed surgically or conservatively?

Aged↗
PubMed2003

Comparison of L-bupivacaine 0.75% and lidocaine 2% with bupivacaine 0.75% and lidocaine 2% for peribulbar anaesthesia.

BACKGROUND: L-Bupivacaine has a safer side-effect profile than bupivacaine. We compared the efficacy of a mixture of L-bupivacaine 0.75% and lidocaine 2% with bupivacaine 0.75% and lidocaine 2% for peribulbar anaesthesia in cataract surgery. METHODS: Ninety patients were allocated randomly to receive 8 ml of a mixture of equal parts of bupivacaine 0.75% and lidocaine 2% or an equal volume of L-bupivacaine and lidocaine 2%. Hyaluronidase 15 IU ml(-1) was added to both solutions. RESULTS: There were significant differences between the groups in clinical end-points. The median time at which the block was adequate to start surgery was 4 min (interquartile range 4-8 min) in the bupivacaine group and 8 min (5-12 min) in the L-bupivacaine group (P=0.002). Median ocular and eyelid movement scores were similarly significantly decreased in the bupivacaine group compared with the L-bupivacaine group at all times (P</=0.03). There was no difference between groups in the incidence of minor complications. CONCLUSIONS: A mixture of bupivacaine 0.75% and lidocaine 2% provides faster onset time than a mixture of L-bupivacaine 0.75% and lidocaine 2%.

Adult↗
PubMed2001

Regulation of cutaneous malignancy by gammadelta T cells.

The localization of gammadelta T cells within epithelia suggests that these cells may contribute to the down-regulation of epithelial malignancies. We report that mice lacking gammadelta cells are highly susceptible to multiple regimens of cutaneous carcinogenesis. After exposure to carcinogens, skin cells expressed Rae-1 and H60, major histocompatibility complex-related molecules structurally resembling human MICA. Each of these is a ligand for NKG2d, a receptor expressed by cytolytic T cells and natural killer (NK) cells. In vitro, skin-associated NKG2d+ gammadelta cells killed skin carcinoma cells by a mechanism that was sensitive to blocking NKG2d engagement. Thus, local T cells may use evolutionarily conserved proteins to negatively regulate malignancy.

Amino Acid Sequence↗
PubMed2000

Comparison of 1% ropivacaine with 0.75% bupivacaine and 2% lidocaine for peribulbar anaesthesia.

We have compared the efficacy of 1% ropivacaine with a mixture of 0.75% bupivacaine and 2% lidocaine for peribulbar anaesthesia in cataract surgery. We used the time to adequate block for surgery, and ocular and eyelid movement scores at 8 min after block as clinical end-points. Ninety patients were allocated randomly to receive 7-10 ml of a mixture of equal parts of 0.75% bupivacaine and 2% lidocaine or an equal volume of 1% ropivacaine alone. Hyaluronidase 15 iu ml-1 was added to both solutions. There were no differences between groups in clinical end-points. Median time at which the block was adequate to start surgery was 8 min (interquartile range 4-10 min) in each group. Median eyelid movement scores were similar in both groups, but the bupivacaine and lidocaine mixture produced a significantly decreased ocular movement score at 2, 4 and 6 min (P < 0.05). There was no difference between groups in the incidence of minor complications. Based on clinical end-points, time to adequate block for surgery and median ocular and eyelid movement scores at 8 min, 1% ropivacaine as the sole agent for peribulbar anaesthesia was comparable with a mixture of 0.75% bupivacaine and 2% lidocaine.

Adult↗
PubMed1997

Ro 32-3555, an orally active collagenase inhibitor, prevents cartilage breakdown in vitro and in vivo.

1. Ro 32-3555 (3(R)-(cyclopentylmethyl)-2(R)-[(3,4,4-trimethyl-2,5-dioxo-1- imidazolidinyl)methyl]-4-oxo-4-piperidinobutyrohydroxamic acid) is a potent, competitive inhibitor of human collagenases 1, 2 and 3 (Ki values of 3.0, 4.4 and 3.4 nM, respectively). The compound is a selective inhibitor of collagenases over the related human matrix metalloproteinases stromelysin 1, and gelatinases A and B (Ki values of 527, 154 and 59 nM, respectively). 2. Ro 32-3555 inhibited interleukin-1 alpha (IL-1 alpha)-induced cartilage collagen degradation in vitro in bovine nasal cartilage explants (IC50 = 60 nM). 3. Ro 32-3555 was well absorbed in rats when administered orally. Systemic exposure was dose related, with an oral bioavailability of 26% at a dose of 25 mg kg-1. 4. Ro 32-3555 prevented granuloma-induced degradation of bovine nasal cartilage cylinders implanted subcutaneously into rats (ED50 = 10 mg kg-1, twice daily, p.o.). 5. Ro 32-3555 dosed once daily for 14 days at 50 mg kg-1, p.o., inhibited degradation of articular cartilage in a rat monoarthritis model induced by an intra-articular injection of Propionibacterium acnes. 6. Ro 32-3555 is a potential therapy for the treatment of the chronic destruction of articulating cartilage in both rheumatoid and osteoarthritis.

Administration, Oral↗
PubMed1996

Reformatting health care delivery.

The healthcare delivery system is undergoing great upheaval as individual providers respond to market pressures for aggressive cost reduction. Roles, relationships, processes, partnerships, and financing arrangements are on the table in the great race for competitive survival. The IDN department addresses issues inherent in the evolution of free-standing acute care centers and private medical staffs into integrated delivery networks. It globally explores alternative managed care and direct contracting at-risk strategies.

Delivery of Health Care, Integrated↗
PubMed1994

Combination of photodynamic therapy (PDT) and melphalan in experimental tumors.

PURPOSE: To investigate whether application of "early" photodynamic therapy (PDT) using a disulphonated aluminium phthallocyanine photosensitizer can potentiate the action of melphalan in experimental RIF-1 tumors in vivo. METHODS AND MATERIALS: Tumors were irradiated with laser light of wavelength 675 nm 60 min after treatment with the photosensitizer and 15 min after melphalan. Melphalan pharmacokinetics were measured using high performance liquid chromatography with optical detection. RESULTS: Melphalan and PDT when given alone, caused a significant delay in tumor growth. This was increased for the combined treatment. Pharmacokinetic analyses showed that levels of free, unreacted melphalan in freely circulating blood are unaffected by combined treatment. However, significant differences in tumor levels were observed between treatment with melphalan alone or in combination. Whereas in the former, melphalan is still present in tumors after 2 h, it was not detectable even at the earliest time of 15-23 min for the combined treatment. CONCLUSION: The antitumor effects were additive with no evidence of significant potentiation.

Animals↗
PubMed1993

Characterization of a small supernumerary ring X chromosome by fluorescence in situ hybridization.

We report on a male with mild learning disabilities who has a supernumerary marker chromosome. The marker chromosome was defined by fluorescence in situ hybridization as a ring X chromosome with breakpoints in the juxacentromeric region. Replication studies suggest that the ring X is late-replicating. However XIST, a gene in the X inactivation centre interval which is expressed exclusively from the inactive X chromosome, is not present on the marker, nor is it expressed in the patient's cells. These results are discussed with respect to karyotype-phenotype correlations and X inactivation.

Base Sequence↗
PubMed1993

Heterocyclic mono-N-oxides with potential applications as bioreductive anti-tumour drugs: Part 1. 8-Alkylamino-substituted phenylimidazo [1,2-a] quinoxalines.

A series of imidazo [1,2-a] quinoxaline mono-N-oxides and their 6- and 9-aza analogues have been substituted in the 8-position with a variety of secondary and tertiary amines, and the compounds evaluated as bioreductively activated cytotoxins. Cytotoxic action against hypoxic cells in vitro was critically dependent upon the structural nature of the 8-substituent and its basicity, with little dependence upon reduction potential. 1,2-Dihydro-8-(4-methylpiperazin-1-yl)-4-phenylimidazo [1,2-a] pyrido [3,2-e] pyrazine 5-oxide (11) had differential hypoxic:oxic toxicity of 15.3 and some novel analogues had differential hypoxic:oxic toxicities of 7.5-17. Other related compounds with either substituted or unsubstituted 8-piperazinyl substituents, or certain straight-chain aminoalkyl substituents, show comparable activity in vitro. Less basic 8-substituents abolished activity, although the 8-morpholinyl derivatives (7 and 8) had differential hypoxic:oxic toxicities of 3-4. Substitution of the 4-phenyl ring with an electron-withdrawing group (F) improved hypoxic potency, but only with a small effect on hypoxic:oxic toxicity, whereas an electron-donating substituent (MeO) reduced hypoxic potency. Perhaps significantly, the 8-unsubstituted analogue 3 was 6-fold less potent, but had comparable differential cytotoxicity in vitro. The most effective novel hypoxia-selective cytotoxins synthesized were the bifunctional 2-nitro-imidazole derivative 1,2-dihydro-8-((4-(3-(2-nitro-1-imidazoyl)-1-hydroxypropyl)- piperazin-1-yl))-4-phenylimidazo [1,2-a] quinoxaline 5-oxide bishydrochloride (37) and its 9-aza analogue 38. These compounds also exhibited the lowest aerobic toxicities in vitro of the new compounds.

Antineoplastic Agents↗
PubMed1992

The use and reliability of psychiatric diagnosis in forensic settings.

The clinical professional encounters conflict whenever he or she enters the courtroom. The psychiatrist's approach must not be simply diagnostic or simply legal. We cannot shed our clinical identity; indeed, the court depends on our clinical identity and expertise in its search for the truth. The psychiatric expert must be able to translate his or her findings for the court, but these findings must come from clinical experience, not some solely legal perspective. The legal system needs our knowledge about the interfaces of mental illness, function, and behavior. After we provide our opinions, however, the legal issues must be left to the lawyers and the final determinations left to the judge or jury.

Criminal Law↗
PubMed1991

Dermal absorption of neat and aqueous volatile organic chemicals in the Fischer 344 rat.

Quantification of dermal absorption of volatile organic chemicals (VOCs) from aqueous solutions is required to understand the potential health hazards resulting from skin exposure to these chemicals in contaminated water. Male Fischer 344 rats were dermally exposed (3.1-cm2 dorsal skin) to neat, one-third saturated, two-thirds saturated, or saturated aqueous solutions of 14 VOCs for 24 hr. Blood samples were obtained via indwelling jugular catheters during exposure (0, 0.5, 1, 2, 4, 8, 12, and 24 hr), and analyzed for the VOCs by gas chromatography using headspace analysis. Absorption of the neat VOCs in this series of chemicals decreased as water solubility decreased. Peak blood levels of VOCs attained during exposure for 24 hr to neat chemicals were: 1,2-dichloroethane (135.1 micrograms/ml), bromochloromethane (113.3 micrograms/ml), chloroform (51.0 micrograms/ml), benzene (24.2 micrograms/ml), tetrachloroethylene (21.1 micrograms/ml), dibromomethane (18.2 micrograms/ml), trichloroethylene (11.6 micrograms/ml), toluene (9.5 micrograms/ml), xylene (8.8 micrograms/ml), hexane (8.0 micrograms/ml), ethylbenzene (5.6 micrograms/ml), styrene (5.3 micrograms/ml), carbon tetrachloride (5.0 micrograms/ml), and 1,1,1-trichloroethane (3.4 micrograms/ml). Blood levels of 1,2-dichloroethane and benzene continued to increase during the 24-hr exposure to neat chemical, while blood levels of the other neat VOCs peaked within 4 hr and then either decreased or remained about the same for the duration of the exposure. Absorption of VOCs from one-third, two-thirds, or saturated aqueous solutions was rapid, and resulted in depletion of the chemical from the solution although only a small amount of water was absorbed. Blood levels of each VOC were directly related to the exposure concentrations. The rapid appearance of VOCs in the blood from aqueous solutions demonstrates that detectable amounts of VOCs were absorbed during exposure of only about 1% of the skin surface area of the rat.

Animals↗