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Biomedical subjects

J P Stone

Publications and source records attributed to J P Stone.

At least 19 recordsLinked to original sources
PubMed2003

Recurarization in the recovery room following the use of magnesium sulphate.

A 67-yr-old man weighing 104 kg, with a history of hypertension, underwent laparoscopic cholecystectomy. His preoperative serum potassium was 3.4 mmol litre(-1). The patient received cisatracurium 14 mg, which was antagonized with neostigmine 2.5 mg and glycoprolate 0.5 mg at the end of the procedure. A repeat dose of neostigmine 2.5 mg and glycoprolate 0.5 mg was required 5 min later, as the neuromuscular block was incompletely antagonized. He was transferred to the recovery room about 10 min after the end of surgery, having had recovery of neuromuscular function demonstrated with no fade on peripheral nerve stimulation at 50 Hz for 5 s. Five minutes later he developed rapid atrial fibrillation, which was treated over 5 min with magnesium sulphate 2 G i.v. Within the next 3 min, the patient developed marked neuromuscular weakness of a non-depolarizing pattern leading to respiratory arrest. This necessitated re-intubation of the trachea and artificial ventilation for 20 min, until there was spontaneous recovery of neuromuscular function demonstrated by peripheral nerve stimulation. Administration of magnesium appears to have caused recurarization in this patient. The dose of magnesium alone would not be expected to cause muscle weakness. Potentiation of neuromuscular blocking drugs by magnesium is well recognized, and we recommend its use is avoided for at least 30 min after reversal of neuromuscular block.

Aged↗
PubMed1993

P-selectin mediates adhesion of platelets to neuroblastoma and small cell lung cancer.

Activated platelets and stimulated endothelial cells express P-selectin, an integral membrane protein receptor that binds monocytes and neutrophils. P-selectin mediates adhesion to glycoproteins with carbohydrate structures containing sialyl-Lewis X. Since many carcinoma cells also express these carbohydrate structures and are known to interact with platelets, we asked whether P-selectin may mediate this interaction. Both small cell lung cancer and neuroblastoma cell lines bound to activated platelets, and this interaction was blocked with inhibitory anti-P-selectin antibodies and by pretreatment of these cancer cells with neuraminidase or trypsin. Platelet binding to the small cell lung cancer cells was not inhibited with anti-GP IIb-IIIa antibody or Arg-Gly-Asp-Ser peptide. Pretreatment of the neuroblastoma cells with inhibitors of N-linked carbohydrate biosynthesis had little effect on binding to P-selectin, indicating that relevant carbohydrate ligand(s) may be O-linked. In addition, lipospheres containing P-selectin specifically bound to cryostat sections derived from a small cell lung tumor and two neuroblastoma tumors, but not to sections of normal lung. These observations demonstrate that P-selectin mediates binding of platelets to small cell lung cancer and to neuroblastoma and suggest a possible role for this lectin in metastasis.

Antibodies, Monoclonal↗
PubMed1988

Pathophysiology of cyanoginosin-LR: in vivo and in vitro studies.

Cyanoginosin-LR, one of the group of virulent cyclic heptapeptide toxins (cyanoginosins) isolated from some strains of the cyanobacterium, Microcystis aeruginosa, kills mice within 1-2 hr after iv or ip injection. Although the liver is a target organ of the toxin, the rapidity of lethality is incompatible with metabolic death from failure of hepatocellular function. However, disintegration of sinusoidal endothelium causes massive intrahepatic hemorrhage. The loss of the structural integrity of hepatic sinusoids provides a previously undescribed mechanism for embolization of disintegrating cells from the liver to the lung. No injury to either cultured bovine pulmonary artery endothelial cells or mouse peritoneal macrophages was observed following prolonged incubation with high concentrations of the toxin, and there was no increase in vascular permeability to 125I-labeled albumin detected before intrahepatic hemorrhage. However, plasma fibronectin increased transiently after toxin injection. Acute, severe thrombocytopenia, a characteristic of cyanoginosin-LR toxicity, remains unexplained since platelets did not concentrate in the lungs, liver, or spleen. There are similarities between the effects of cyanoginosin-LR and of the lipopolysaccharide endotoxins, such as elevations of plasma levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha.

Animals↗
PubMed1987

Assessment of interaction among three carcinogens on rat mammary carcinogenesis in a factorially designed experiment.

Female Sprague-Dawley rats were given by stomach tube 7,12-dimethylbenz[a]anthracene [(DMBA) CAS: 57-97-6] on the 77th day of age at the rate of 1.6 mg/100 g body weight, or procarbazine [(PCZ) CAS: 671-16-9] on the 84th day of age at the rate of 10 mg/100 g body weight, or 0.5 Gy of total-body x-rays on the 91st day of age, singly or in all possible combinations or no treatment. All rats were studied for mammary carcinogenesis for 370 days after the 84th day of age. Three measures of mammary carcinogenesis were studied. These were the incidence of rats with mammary adenocarcinomas, or mammary fibroadenomas, or mammary neoplasia of either type. Each of these measures was studied also for rats with 2 or more or 3 or more mammary neoplasms. Assessment of possible interaction among the three carcinogens with regard to the incidence of neoplasms was done by time-independent or time-dependent methods, both of which gave remarkably consistent results. For rats with 1 or more adenocarcinomas, 1 or more fibroadenomas, or 1 or more adenocarcinomas and/or fibroadenomas, both methods showed no interaction among the carcinogens, which can, therefore, be considered to have produced additive effects. An exception to this finding of additivity was an apparent synergistic interaction between DMBA and PCZ when the measures of rats with 2 or more, or 3 or more mammary neoplasms of either type, or 3 or more fibroadenomas were analyzed; these analyses, however, were based on relatively small numbers of rats with multiple tumors. Since no interactions were found for the usual measure of carcinogenesis, namely, incidence of rats with 1 or more neoplasms, the overall conclusion is that DMBA, PCZ, and x-ray act additively in the induction of mammary neoplasms in the female Sprague-Dawley rat.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1985

Carcinogenic responses to chemicals applied directly to rat mammary glands in situ.

In four experiments, concentrated glycerin suspensions of 7,12-dimethylbenz[a]anthracene (DMBA), or the water-soluble compounds, N-methyl-N-nitrosourea (MNU), N-ethyl-N-nitrosourea (ENU), and 4-nitroquinoline-N-oxide (4-NQO) were delivered into pockets in the mammary fat pads in female Sprague-Dawley rats. In a 90-day experiment, each of three groups of 20-22 rats were treated with either 25, 50 or 100 micrograms DMBA delivered to each of four sites in each rat per group. Dose-related responses were detected for incidence of rats with mammary adenocarcinoma (MAC), and for number of MAC per treated site. In a 120-day study, each of three groups of 20 animals were treated with either 250, 500 or 1000 micrograms MNU at each of 80 sites per group. Dose-related MAC responses were detected for incidence of rats with MAC, number of MAC per treated site, and time to detection of MAC. In two experiments of 90 days duration, groups of 20 females were treated with either 1000 micrograms ENU or 1000 micrograms 4-NQO at each of 80 sites per group. ENU produced a total of 27 MAC sites in 65% of the rats, and 4-NQO produced a total of 26 MAC in 60% of the rats. A comparison of the time to detection of all MAC data for the three water-soluble compounds at the 1000 micrograms treatment level, or on the basis of moles per treatment, yielded a carcinogenic potency relationship of 4-NQO greater than ENU greater than MNU.

4-Nitroquinoline-1-oxide↗
PubMed1984

Differences in DMBA-induced mammary neoplastic responses in two lines of Sprague-Dawley rats.

It has been reported that female Sprague-Dawley rats obtained from a U.S. source and studied in the U.S. gave a larger and more rapid mammary neoplastic response to radiation than did female Sprague-Dawley rats obtained from a Dutch source and studied in The Netherlands. To learn if the different mammary neoplastic responses of the two 'lines' of Sprague-Dawley rats are due to inherent differences between the lines of rats or due to differences in experimental conditions, two groups of rats from the American source and one group from the Dutch source were studied for their response to a chemical carcinogen, dimethylbenzanthracene (DMBA), at the same laboratory. When 10 mg of DMBA per 100 g body wt was given by stomach tube to 28 rats from the Dutch source, 367 days later approximately 25% of these rats had developed mammary carcinomas and approximately 18% had developed mammary fibroadenomas. When the same dose of DMBA was given to rats from the U.S. source, 300 days later 90 and 100% had developed mammary carcinomas and 83 and 95% had developed mammary fibroadenomas. Similar trends were found for the number of neoplasms per rat and the mean time of appearance of the neoplasms. It was concluded that there are inherent differences between Sprague-Dawley rats obtained in the U.S. and Sprague-Dawley rats obtained in The Netherlands in regard to their mammary neoplastic responses to DMBA, as well as in their responses to radiation. Genetic differences between the two lines were confirmed by establishing dissimilarities in the expression of erythrocyte antigens coded for by RT1 (major histocompatibility complex).

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Mode of payment and identification with a regular doctor. A prospective look at reported use of services.

Despite the apparent success of health maintenance organizations (HMOs) in lowering the costs of health care, they have been criticized for other reasons, including the lack of doctor-patient continuity in the patient's having a regular doctor. Consistent with previous research, HMO members sampled from Los Angeles County (N = 190) were less likely to identify with a regular doctor than comparable fee-for-service (FFS) subscribers (N = 653) (P less than 0.001). When differences in this variable were not controlled statistically, HMO members reported higher rates of physician visits, but only for acute respiratory problems (P less than 0.05). It was not until differences in having a regular doctor were taken into account that HMO members were found to report higher rates of use for all symptoms (P less than 0.05) as well as for digestive problems (P less than 0.10). These findings suggest the importance of taking physician-patient continuity into account when comparing utilization rates across health plans. Additionally, few differences were found in reports of morbidity, although HMO members were less likely to report cold symptoms during this 1-year survey than comparable FFS subscribers (P less than 0.05).

Adolescent↗
PubMed1983

Effect of interval between neutron radiation and diethylstilbestrol on mammary carcinogenesis in female ACI rats.

Both radiation and diethylstilbestrol (DES) are carcinogens for the mammary gland of ACI female rats. When DES is given at about the same time as radiation, DES and radiation interact in a synergistic fashion particularly in regard to the number of mammary adenocarcinomas per rat. We have studied the effect of increasing the time interval between radiation and DES on the capacity of DES to enhance (promote?) radiation-induced mammary carcinogenesis. DES, in the form of a compressed pellet containing a mixture of cholesterol and DES, formulated to average 1.25 mg of DES/100 gr body weight, was given to groups of approximately 28 rats at 2 days before, or 50, 100 or 200 days after 0.064 Gy of 0.43 MeV neutron radiation. At each time that DES was given to irradiated rats, DES was also given to nonirradiated rats. All rats were studied for 375 days after the date of the DES administration. When the total number of mammary adenocarcinomas was calculated as a percentage of 24 sites per rat at-risk, DES and radiation always produced a response that was larger than the sum of the responses of DES alone plus radiation alone. This result suggests that these two agents can interact in a synergistic fashion. The interaction between radiation and DES did not decline as the time interval between radiation and DES was lengthened. This result suggests that radiation-induced (initiated?) mammary carcinogenesis is not subject to repair since DES enhancement (promotion?) continues to be effective over long time intervals.

Adenocarcinoma↗
PubMed1982

Induction of mammary neoplasms in the ACI rat by 430-keV neutrons, X-rays, and diethylstilbestrol.

Mammary tumorigenesis was studied in female ACi rats after treatment with X-irradiation or neutron-irradiation, with or without diethylstilbestrol (DES) treatment. The mortality-corrected cumulative tumor rate based on all mammary neoplasms and the mortality-corrected incidence based on the first neoplasms only have been derived. In non-DES-treated animals, at the relatively high radiation doses studied, all dose-effect relationships were consistent with relative biological effectiveness (RBE) values slightly in excess of 10. In DES-treated rats definite findings were observed at neutron doses as low as 0.01 Gy (1 rad). The dose-effect relationship in DES-treated rats showed a strong sublinearly (dose exponent less than 1) at low neutron doses. RBE values in DES-treated rats increased in inverse proportion to the square root of the neutron dose, and exceeded 100 at a neutron dose of 0.01 Gy (1 rad).

Adenocarcinoma↗
PubMed1981

Synergism of estrogens and X-rays in mammary carcinogenesis in female ACI rats.

A previously demonstrated synergistic interaction between diethylstilbestrol (DES) and radiation on rat mammary carcinogenesis was extended to another estrogen, 17-ethinylestradiol (EE2). These newly reported results with EE2 demonstrated that the previously reported synergistic interaction between DES and radiation is not confined to just DES. Instead, these new results implied that the synergistic interaction is a synergistic interaction between the estrogenic activity of DES and radiation on rat mammary carcinogenesis. Female inbred ACI rats were used. By the end of the experiment, no neoplasia was detected in rats bearing cholesterol pellets, with and without X-ray exposure. No significant tumor data were obtained from rats treated with 0.1 me EE2, with and without X-rays. Approximately 50% of the rats treated with DES and approximately 90% of the rats treated with 1 mg EE2 had 1 or more mammary adenocarcinomas (MAC). X-rays synergistically increased the number of MAC per rat in the groups implanted with DES or 1 mg EE2. X-rays also increased the trend toward earlier increased incidence of rats with MAC as compared to rats treated with estrogens only. All rats treated with DES and 1 mg EE2 had pituitary tumors. The mean weight of the pituitary tumors in the groups treated with 1 mg EE2 was approximately 1.5 times that of the groups treated with DES. Mean terminal plasma prolactin levels for rats treated with 1 mg EE2 or DES were, respectively, 17.5 and 9.5 times control values.

Adenocarcinoma↗
PubMed1980

Soybean diet lowers breast tumor incidence in irradiated rats.

This paper examines the relationship between feeding a diet rich in protease inhibitors and the reduction of mammary cancer induced by x-irradiation in Sprague-Dawley rats. Of a total of 145 irradiated animals, 44% of the 45 rats fed a raw soybean diet containing a high concentration of protease inhibitor developed mammary tumors as compared to 74% of 50 rats fed a casein diet containing no protease inhibitor. Animals fed Purina rat chow which contained low levels of protease inhibitor exhibited a 70% mammary tumor incidence. No spontaneous neoplasms were found in any of the non-irradiated animals on the raw soybean diet whereas about 10% of the animals on the protease-free diet developed tumors. Thus, soybeans which are rich in protease inhibitors reduced the induction of mammary cancer in x-irradiated rats. This work suggests that diets rich in protease inhibitors may contribute to reducing cancer incidence in man.

Animals↗