The Rotational Spectra, Structure, Internal Dynamics, and Electric Dipole Moment of the Argon-Ketene van der Waals Complex.

Pulsed-beam Fourier transform microwave spectroscopy was used to observe and assign the rotational spectra of the argon-ketene van der Waals complex. Tunneling of the hydrogen or deuterium atoms splits the a- and b-type rotational transitions of H(2)CCO-Ar, H(2)(13)CCO-Ar, H(2)C(13)CO-Ar, and D(2)CCO-Ar into two states. This internal motion appears to be quenched for HDCCO-Ar where only one state is observed. The spectra of all isotopomers were satisfactorily fit to a Watson asymmetric top Hamiltonian which gave A=10 447.9248(10) MHz, B=1918.0138(16) MHz, C=1606.7642(15) MHz, Delta(J)=16.0856(70) kHz, Delta(JK)=274.779(64) kHz, Delta(K)=-152.24(23) kHz, delta(J)=2.5313(18) kHz, delta(K)=209.85(82) kHz, and h(K)=1.562(64) kHz for the A(1) state of H(2)CCO-Ar. Electric dipole moment measurements determined &mgr;(a)=0.417(10)x10(-30) C m [0.125(3) D] and &mgr;(b)=4.566(7)x10(-30) C m [1.369(2) D] along the a and b principal axes of the A(1) state of the normal isotopomer. A least squares fit of principal moments of inertia, I(a) and I(c), of H(2)CCO-Ar, H(2)(13)CCO-Ar, and H(2)C(13)CO-Ar for the A(1) states give the argon-ketene center of mass separation, R(cm)=3.5868(3) Å, and the angle between the line connecting argon with the center of mass of ketene and the C=C=O axis, θ(cm)=96.4 degrees (2). The spectral data are consistent with a planar geometry with the argon atom tilted toward the carbonyl carbon of ketene by 6.4 degrees from a T-shaped configuration. Copyright 2001 Academic Press.

A Phase I dose escalation trial of continuous infusion paclitaxel to augment high dose cyclophosphamide and thiotepa plus stem cell rescue for the treatment of patients with advanced breast carcinoma.

BACKGROUND: Paclitaxel, an effective chemotherapeutic agent in the management of breast carcinoma, may have activity in women whose disease has recurred after high dose chemotherapy. With this is mind the authors explored the addition of a 120-hour continuous infusion of paclitaxel to a previously reported regimen comprised of high dose cyclophosphamide and thiotepa. METHODS: Thirty-one women with advanced breast carcinoma (30 patients with Stage IV disease and 1 patient with Stage IIIB disease) underwent harvest and cryopreservation of bone marrow and/or peripheral blood progenitor cells. High dose cyclophosphamide (2.5 g/m2) and thiotepa (225 mg/m2) were administered intravenously on Days -7, -5, and -3. Paclitaxel was administered as a 120-hour continuous infusion starting on Day -7. RESULTS: Three patients were treated at the initial cohort dose of 50 mg/m2 (over 120 hours), 6 patients at 100 mg/m2, 6 patients at 125 mg/m2, 6 patients at 150 mg/m2, 6 patients at 180 mg/m2, and 4 patients at 210 mg/m2. All patients completed the treatment protocol as planned with no associated transplant-related deaths. Mucositis as evidenced by either stomatitis or noninfectious diarrhea was experienced by all patients and was determined to be the dose-limiting toxicity at the 210 mg/m2 dose level. One patient with dose-limiting mucositis required intubation for airway protection and also experienced Grade 3 (according to the Cancer and Leukemia Group B common toxicity grading scale) pulmonary and neurologic toxicity. Only one Grade 3 toxicity was encountered below the maximum tolerated dose in a patient who developed diffuse alveolar hemorrhage at a dose of 125 mg/m2. No allergic reactions or clinical evidence of peripheral neuropathies were encountered. Cardiac, hepatic, and renal toxicities were minimal. Response rates in this previously treated patient population were difficult to assess in light of the high incidence of bone metastases; an overall response rate of 24% was obtained. CONCLUSIONS: Paclitaxel at a dose of 180 mg/m2 as a 120-hour continuous infusion may be added safely to high dose cyclophosphamide and thiotepa with autologous stem cell rescue. Further studies are ongoing to evaluate the efficacy and further define the toxicity of this recommended Phase II dose.

Mainstream end-tidal carbon dioxide monitoring in the neonatal intensive care unit.

BACKGROUND: Continuous noninvasive monitoring of arterial carbon dioxide (CO2) in neonatal intensive care unit (NICU) patients would help clinicians avoid complications of hypocarbia and hypercarbia. End-tidal CO2 monitoring has not been used in this population to date, but recent technical advances and the introduction of surfactant therapy, which improves ventilation-perfusion matching, might improve the clinical utility of end-tidal monitoring. OBJECTIVE: To determine the accuracy and precision of end-tidal CO2 monitoring in NICU patients. DESIGN: Nonrandomized recording of simultaneous end-tidal and arterial CO2 pairs. SETTING: Two university NICUs. PATIENTS: Forty-five newborn infants receiving mechanical ventilation who had indwelling arterial access, and a predefined subsample of infants who were <1000 g birth weight, <8 days of age, and who received surfactant therapy (extremely low birth weight -ELBW- <8). OUTCOME MEASURES: The correlation coefficient, degree of bias, and 95% confidence interval were determined for both the overall population and the ELBW <8 subgroup. Those factors which significantly influenced the bias were identified. The ability of the end-tidal monitor to alert the clinician to instances of hypocarbia or hypercarbia was determined. RESULTS: There were 411 end-tidal/arterial pairs analyzed from 45 patients. The correlation coefficient was 0.833 and the bias was -6. 9 mm Hg (95% confidence interval, +/-11.5 mm Hg). The results did not differ markedly in the ELBW <8 infants. Measures of the degree of lung disease, the ventilation index and the oxygenation index, had small influences on the degree of bias. This type of capnometry identified 91% of the instances when the arterial CO2 pressure was between 34 and 54 mm Hg using an end-tidal range of 29 to 45 mm Hg. End-tidal values outside this range had a 63% accuracy in predicting hypocarbia or hypercarbia. CONCLUSION: End-tidal CO2 monitoring in NICU patients is as accurate as capillary or transcutaneous monitoring but less precise than the latter. It may be useful for trending or for screening patients for abnormal arterial CO2 values.

Assessment instruments in respiratory care.

The basis for using therapist-driven protocols effectively is an accurate assessment of the patient's respiratory status. Patients must be assessed to initiate indicated therapy and reassessed so that therapy can be modified or discontinued if no longer needed. This article addresses the role of respiratory therapists in patient assessment for the selection of appropriate and effective protocols. It also describes the use of a systematic and consistent process for patient assessment.

Posteriorly based, lateral lingual flaps for alveolar cleft bone graft coverage.

The use of posteriorly based, lateral lingual flaps for primary oral coverage of alveolar cleft grafts is reported. These flaps offer dependable vascularity, versatility, and viable augmentation of tissue-deficient areas while avoiding the sacrifice of covering tissue from already scarred lips or maxillary surfaces.

An in vivo model for evaluating the response of pulp to various biomaterials.

An in vivo model has been designed to study the acute response of exposed or unexposed dental pulp to the topical application of various biomaterials. This model permits sequential microscopic observations of the microvascular system of dental pulp before and after application of pulp capping agents, cementing agents, or cavity liners. The use of this experimental model provides useful information related to the tolerability of dental pulp to various biomaterials used in dentistry. Furthermore, this model serves as a useful supplement to more traditional long term methods for evaluating the biocompatability of dental materials.

Mandibular condylectomy in the guinea pig: quantitative triple fluorochrome study.

Different-colored fluorochromes were administered sequentially to guinea pigs and the rate of bone formation measured in their condylectomized control contralateral hemimandibles. The values for labeled bone for condylectomized hemimandibles were lower than for the control contralateral hemimandibles of the same guinea pig. The differences in values of condylectomized and control contralateral sides for DCTC- and total surface area-labeled bone were statistically significant, but were not statistically significant for DCAF- and hematoporphyrin-labeled bone. There was partial regeneration of the condylar process. Although the condylectomized area was nearly normal in shape, its size and proportions were different from those of the contralateral hemimandibles that were not operated on. The greatest differences were noted in the length, height, and the distances measured between the inferior alveolar foramen and the mental foramen and the posterior border of the condyle.