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Biomedical subjects

R Ambrose

Publications and source records attributed to R Ambrose.

7 recordsLinked to original sources
PubMed1997

Calculation of soil-water and benthic sediment partition coefficients for mercury.

To accurately model mercury transport to water bodies, an assessment of this pollutant's behavior in the watershed is critical. Partition coefficients, defined as an estimate of the ratio of the pollutant concentration sorbed onto soil/sediment particles to the pollutant concentration dissolved in pore water at equilibrium, is an important term in multimedia models. In this paper, partition coefficients are calculated for two broad species of mercury: inorganic mercuric mercury (Hg-II) and methylmercury (MHg). Although there is considerable variability in the calculated values, the approximate mean values for the soil-water partition coefficients range from 3.3 x 10(3) to 6.0 x 10(4) L/kg for Hg-II and 2.0 x 10(1) to 6.7 x 10(3) L/kg for MHg. For the benthic sediment partition coefficients, the values range from 5.7 x 10(3) to 9.9 x 10(5) L/kg for Hg-II, and 6.5 x 10(2) to 1.1 x 10(5) L/kg for MHg.

Animals↗
PubMed1996

The paranasal sinuses before and after radiotherapy for nasopharyngeal carcinoma: a computed tomographic study.

A study comparing the pre- and post-radiotherapy computed tomographic scans of patients treated for nasopharyngeal carcinoma revealed that the incidence of major mucosal abnormality was significantly increased and approximately doubled after radiotherapy. The most significant factor predicting major mucosal abnormality after radiotherapy was the presence of tumour in the sinus before treatment. In the maxillary sinus there was significant association of major mucosal abnormality before and after radiotherapy although this was not so for the other sinuses. The mucosal changes observed were evident as early as six months after radiotherapy.

Adult↗
PubMed1996

Abnormalities of the paranasal sinuses in patients with nasopharyngeal carcinoma: a computed tomographic study.

A retrospective study of computed tomography scans of the paranasal sinuses of 131 control subjects in Hong Kong revealed minor mucosal abnormalities in more than half of the ethmoid sinuses. Major abnormalities were present in seven per cent of maxillary, five per cent of anterior ethmoid and four per cent of posterior ethmoid sinus. In 85 patients with nasopharyngeal carcinoma the prevalence of minor mucosal abnormalities in the sinuses was similar to that of the control group but major mucosal abnormalities were significantly more common in the anterior and posterior ethmoids at 15 per cent and 21 per cent of the respective sinuses (p < 0.001).

Adult↗
PubMed1995

Antiinflammatory activity of a Ghanaian antiarthritic herbal preparation: III.

alpha-Amyrin palmitate, present in a Ghanaian antiarthritic herbal preparation of Alstonia boonei, Elaies guineensis and Rauvolfia vomitoria, was synthesised and tested on complete Freund's adjuvant-induced arthritic rats. Administered orally at 56 mg/kg body weight (BW) daily for 8 days from days 11 to 18 post adjuvant (acute) or at 66 mg/kg BW every 48 h for 5 days from days 32 to 40 (chronic), the drug returned the increases in serum hyaluronate and blood granulocytes towards non-arthritic levels and corrected the moderate anaemia of adjuvant arthritis. Histological examinations of the proximal interphalangeal foot joints showed reduced synovial proliferation and invasion of joints and reduced leucocyte infiltration of bone marrow and periarticular tissue in treated rats. The results suggest that alpha-amyrin palmitate contributes to the previously shown antiarthritic effect of the herbal preparation.

Acute Disease↗
PubMed1994

Effect of alpha-amyrin palmitate on adjuvant arthritis.

alpha-amyrin palmitate was synthesized and tested on adult male Wistar rats made arthritic by subplantar injection of complete Freund's adjuvant. When administered orally at 66 mg/kg BW every 48 h for 5 days from days 32 to 40 post-adjuvant and assessed on day 50, alpha-amyrin palmitate returned the increases in serum hyaluronate and blood granulocytes toward non-arthritic levels and corrected the moderate anaemia of adjuvant arthritis. Histological examinations of the second and third proximal foot interphalangeal joints showed reduced synovial proliferation and invasion of joints and reduced leucocyte infiltration of bone marrow in alpha-amyrin palmitate-treated rats. In addition, the drug prevented or reduced bone (subchondral or cortical) and cartilage (articular) destruction in arthritic rats. The results suggest that alpha-amyrin palmitate is antiarthritic in the adjuvant model of arthritis in rats.

Animals↗