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Biomedical subjects

N W Rizk

Publications and source records attributed to N W Rizk.

23 records · Page 2Linked to original sources
PubMed1985

Selection of patients with non-small-cell lung carcinoma for surgical resection.

Cancer of the lung is rapidly increasing in incidence in both sexes and soon will overtake breast cancer as the most deadly cancer in women. Selection of patients with non-small-cell carcinoma for surgical resection is largely based on preoperative clinical staging, using the American Joint Committee on Cancer's TNM-based group staging protocol. Determining the presence or absence of mediastinal nodal metastasis is paramount and is currently best achieved by computed tomographic scanning of the chest and biopsy of enlarged nodes via mediastinoscopy. Certain types of stage III lesions, previously excluded from surgical treatment, are now recognized as operable.

Humans↗
PubMed1984

Site of deposition and factors affecting clearance of aerosolized solute from canine lungs.

We determined the influence of several factors on lung solute clearance using aerosolized 99mTc-diethylenetriaminepentaacetate. We used a jet nebulizer-plate separator-balloon system to generate particles with an activity median aerodynamic diameter of 1.1 micron, administered the aerosol in a standard fashion, and determined clearance half times (t1/2) with a gamma-scintillation camera. The following serial studies were performed in five anesthetized, paralyzed, intubated, mechanically ventilated dogs: 1) control, with ventilatory frequency (f) = 15 breaths/min and tidal volume (VT) = 15 ml/kg during solute clearance; 2) repeat control, for reproducibility; 3) increased frequency, with f = 25 breaths/min and VT = 10 ml/kg; 4) positive end-expiratory pressure (PEEP) of 10 cmH2O; 5) unilateral pulmonary arterial occlusion (PAO); and 6) bronchial arterial occlusion (BAO). Control t1/2 was 25 +/- 5 min and did not change in the repeat control, increased frequency, or BAO experiments. PEEP markedly decreased t1/2 to 13 +/- 3 min (P less than 0.01), and PAO increased it to 37 +/- 6 min (P less than 0.05). We conclude that clearance from the lungs by our method is uninfluenced by increased frequency, increases markedly with PEEP, and depends on pulmonary, not bronchial, blood flow.

Aerosols↗
PubMed1983

Mechanism of cough and bronchoconstriction induced by distilled water aerosol.

We studied the relationship between cough and bronchoconstriction caused by inhaled distilled water aerosol in 8 subjects with asthma by measuring specific airways resistance (SRaw) and recording cough while subjects breathed serially increasing volumes of distilled water or normal saline aerosol produced by an ultrasonic nebulizer. We performed the distilled water dose-response curves after no treatment and after treatment with cromolyn aerosol, lidocaine aerosol, or atropine aerosol in doses of 0.2 mg and 2.0 mg on separate days. Without prior treatment, distilled water aerosol caused cough in 7 of 8 subjects and a marked increase in SRaw in every subject, whereas saline aerosol did not cause cough or a greater than 50% increase in SRaw in any subject. The 2 doses of atropine caused an equivalent reduction in baseline SRaw, but 2.0 mg caused greater inhibition of water-induced bronchoconstriction than did 0.2 mg. Neither dose of atropine inhibited cough. These data suggest that water-induced bronchoconstriction involves cholinergic nerves and that water-induced cough is not dependent on bronchoconstriction. Lidocaine inhibited cough but not bronchoconstriction, whereas cromolyn inhibited bronchoconstriction but not cough, suggesting that cromolyn does not inhibit bronchoconstriction by a generalized inhibition of airway afferent nerves.

Adolescent↗