Multiple in vivo liver biopsies using a freeze-clamping technique.

A multiple in vivo liver biopsy technique was developed to measure labile metabolites (creative phosphate [CP], ATP, lactate) without interfering with normal perfusion and metabolism. Anesthetized rats (n = 7) had a midline abdominal incision done to expose the liver. Four biopsies were taken across 20 min. Bleeding was controlled by a small, nontraumatic clamp proximal to the biopsy. Prefrozen dressing forceps grasped the liver and scissors cut the biopsy, which was frozen in liquid nitrogen. Bleeding was minimal and hemodynamic stability was preserved. This technique has few complications, bleeding is easily controlled, and it allows for large multiple biopsies, which give reliable metabolic data and can be consistently taught.     

The rationale and indications for equilibration in the primary dentition.

One type of malocclusion in the primary dentition is posterior crossbite caused by premature deflective occlusal interferences. The primary canines are the teeth that most frequently contribute to a laterally guided centric occlusion that creates a functional malocclusion. Because this is not a self-correcting situation, these types of posterior crossbites should be identified early and evaluated for possible correction through occlusal equilibration. A case that illustrates early correction of a unilateral functional posterior crossbite by equilibration and the 5-year results are presented.     

Use of a physician-directed questionnaire to define a consensus about management of breast cancer: implications for assessing costs and benefits of treatment.

The present study was designed to assess the preferred methods of treatment of early breast cancer by United States oncologists, to define the impact of published clinical trials on their practice, and to define questions related to clinical decision making that should be subjected to further research. A questionnaire was mailed to 405 oncologists of all three disciplines (medical, radiation, and surgical oncology) and to 60 oncology nurses who practice in the United States. The questionnaire included clinical scenarios of: (a) a patient with primary breast cancer; (b) a premenopausal woman with node-negative breast cancer; and (c) a postmenopausal woman with estrogen receptor (ER)-negative, node-positive breast cancer. Respondents were asked to describe their preferred management for each scenario. Our study demonstrates a consensus that modified radical mastectomy, or partial mastectomy plus radiation therapy, should be offered as equal options to selected patients with primary breast cancer; this consensus is supported by results of clinical trials. We also found agreement that adjuvant chemotherapy should be offered to premenopausal women with node-negative, ER-negative breast cancer. There was a similar consensus in favor of adjuvant chemotherapy for postmenopausal patients with ER-negative, node-positive breast cancer, despite the absence of improvement in overall survival in large, mature, controlled randomized trials (and in a meta-analysis). We suggest that further research be undertaken into factors that influence decision making by oncologists when they consider the administration of adjuvant chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics of respondents and non-respondents to a mailed questionnaire.

In establishing a cohort of U.S. nurses, an assessment of response bias was made comparing respondents and non-respondents with regard to age, education, state of residence, employment status, field of employment, and major specialty. Overall, the 122,328 respondents (69.7 per cent) and 43,222 non-respondents were quite similar. Together with the reasonable response rate in a homogeneous population, this suggests that estimation of exposure-disease associations is unlikely to be affected by major bias due to non-response.     

Cisplatin plus cytosine arabinoside in adults with malignant gliomas

Summary A combination of cisplatin and cytosine arabinoside was used to treat 21 patients with glioblastomas and 5 patients with recurrent grade 11 gliomas. Cisplatin 60–100 mg/m² was given I.V. in 250 ml 0.45% saline and preceded by 500 ml dextrose 5% in 0.45% saline. Mannitol 50 g was given I.V. concurrently with the cisplatin. Cytosine arabinoside 500–1000 mg/m² was given by rapid I.V. infusion immediately after the cisplatin. Of 25 evaluable patients, 10 (40%) experienced objective tumor shrinkage on CT scan, and 6 (24%) stabilized. There were 2 complete remissions. Patients who had had no prior treatment had a higher response rate (58%) than those previously treated (23%). Myelosuppression occurred in some patients 2–3 weeks after treatment. Gastrointestinal toxicity (vomiting and diarrhea) was dose-limiting. Two patients had possible neurological toxicity. Recommended doses for further studies are cisplatin 90 mg/m² and cytosine arabinoside 900 mg/m².     

Motor activity induced by substance P in rats

The effects of intraventricular injections of various doses (20.00, 5.00, 1.25, 0.30 and 0.07 μg) of synthetic Substance P on motor activity in rats were investigated. Activity scores as determined by photocell counts recorded for a 15 min test period were significantly increased in animals injected with 0.30 and 1.25 μg/rat Substance P. The other doses examined did not affect activity. Doses in the range of 40–80 μg produced immobility, rigidity and barrel rotations. Hypersalivation as indicated by a wet fur following an episode of grooming was observed in several animals. Administration of Substance P, in a dose of 0.60 μg, in combination with or 30 min after injections of 2 mg/kg d-amphetamine and 1 mg/kg apomorphine did not potentiate or reduce the increased activity and stereotypy induced by these two drugs.     

The in vitro metabolism of mephentermine

The metabolism of mephentermine (Ie) to phentermine (Ia), N-hydroxyphentermine (Ib) and N-hydroxymephentermine (If) was investigated using hepatic microsomal preparations from various species. Liver microsomes from rabbit were the best homogenate fractions to metabolise Ie. The effect of incubation times, various substrate concentrations, addition of selective inhibitors and activators and species differences suggested that the dealkylation of Ie to Ia involved a separate metabolic route than the N-oxidation of Ie to Ib and If and that both hydroxylamino compounds Ib and If resulted from metabolic oxidation at the nitrogen atom of Ie. A mechanism explaining the separate formation of Ib and If through a common intermediate resulting from N-oxidation of Ie is proposed. The synthesis and the properties of N-methyl-(α,α-dimethyl-β-phenethyl)nitrone (Ig) are reported.