Search PubMed⌕ Search

Biomedical subjects

D C Zavala

Publications and source records attributed to D C Zavala.

At least 37 records · Page 2Linked to original sources
PubMed1978

An effect of paraquat on the lungs of rabbits. Its implications in smoking contaminated marihuana.

Thirty-six rabbits received the herbicide, paraquat (1,1'-dimethyl-4,4'-dipyridylium dichloride), by selective intrabronchial instillation in doses ranging from 0.1 gm to 1 pg. Sixteen additional rabbits were given paraquat dichloride (25 mg/kg of body weight) intraperitoneally, subcutaneously, intravenously, or orally. The lung of the rabbit proved to be highly sensitive to paraquat administered by intrabronchial deposition, moderately sensitive to intravenously administered paraquat, and resistant to the chemical when given intraperitoneally or subcutaneously. One picogram of paraquat dichloride delivered by bronchial catheter produced a 1.0-mm pulmonary lesion consisting of focal hemorrhage, congestion of capillaries, intra-alveolar macrophages, and moderate thickening of the alveolar septa. This finding suggests that pulmonary damage could potentially result from smoking marihuana that has been sprayed with paraquat.

Administration, Oral↗
PubMed1977

Trephine air drill, bronchial brush, and fiberoptic transbronchial lung biopsies in immunosuppressed patients.

Seventy-nine nonthoracotomy lung and bronchial biopsy procedures were performed in 52 immunosuppressed patients: 22 renal transplants, 24 lymphoreticular malignancies, and 6 other disorders. The total diagnostic yield was 74 per cent (23 of 31) of the forcepts transbronchial biopsy procedures, 82 per cent (14 of 17) of the percutaneous trephine lung biopsies, and 28 per cent (9 of 31) of the bronchial brush biopsies. An etiologic diagnosis, including a variety of viral fungal, and parasitic diseases, was obtained in 42 per cent (13 of 31) of the transbronchial biopsy procedures and 65 per cent (11 of 17) of the percutaneous trephine lung biopsies. The etiologic diagnostic yield was increased to 48 per cent when bronchial brushing was combined with forceps transbronchial biopsy. Hemorrhage complicated 26 per cent of the transbronchial biopsy procedures and 17 per cent of the percutaneous trephine biopsies, whereas pneumothorax occurred in 19 per cent and 60 per cent, respectively. Hemorrhagic complications in patients undergoing transbronchial biopsy occurred 3 times as frequently among the uremic patients (5 of 11, 45 per cent) as among the nonazotemic patients (3 of 20, 15 per cent). Patients with thrombocytopenia, when corrected by platelet infusion, presented no increased risk. Of the 52 patients, 19 (36 per cent) died 2 to 60 days after biopsy, but no fatalities were related per se to the biopsy procedure.

Adolescent↗
PubMed1977

Plasma levels of lidocaine following nebulized aerosol administration.

The venous (plasma) levels of lidocaine were measured in five subjects following nebulization of a 280-mg dose via intermittent positive pressure breathing (IPPB) and nebulization of a 400-mg dose via ultrasound. Even though a lower dose of lidocaine was given by IPPB, this system of delivery produced higher plasma concentrations of the drug than ultrasound and also was more effective in eliminating the gag reflex. In the entire study, plasma concentrations of lidocaine did not exceed 1.1 mug/ml, which is far below toxic levels. Aerosolized lidocaine, administered by IPPB, is a safe and effective topical anesthetic agent which may be useful for instrumentation of the upper airway.

Adult↗
PubMed1977

Removal of foreign bodies (two teeth) by fiberoptic bronchoscopy.

In special situations the flexible fiberoptic bronchoscope, with its increased visual range and extended capabilities for extraction, may be utilized to augment rigid bronchoscopy. Recently developed tools for extraction (claw, basket, forceps, and balloon catheter) may be inserted through the channel of the fiberoptic bronchoscope to capture small, peripheral foreign objects. We present the case of a 76-year-old man in whom two aspirated teeth were removed from the right lower lobe (RB9a and RB9b) using the fiberoptic bronchoscope, a wire basket, and a Fogarty balloon catheter. Rigid tube bronchoscopy was contraindicated because the patient had just sustained a fractured skull and jaw in an automobile accident.

Aged↗
PubMed1976

Transbronchial biopsy via flexible fiberoptic bronchoscope; results in 164 patients.

The diagnostic accuracy and complication rate of transbronchial forceps lung biopsy combined with bronchial brushing were analyzed in 164 consecutive patients, of whom 95 had nonmalignant disease and 51 had malignant disease. Eighteen patients with abnormal chest radiographs had normal transbronchial forceps lung biopsies and no established diagnosis. Satisfactory specimens were obtained in 153 patients (93 per cent), with diagnositc accuracies of 62, 64, and 67 per cent, respectively, in infectious, interstitial, and malignant lung disease. The over-all diagnostic accuracy was 57 per cent. Seven patients were diagnosed as having metastatic carcinoma to the lung by transbronchial forceps lung biopsy, but brush biopsy was psoitive in only 3. Of the 23 patients with primary lung carcinoma diagnosed by transbronchial forceps lung biopsy, 21 had positive brush biopsies. An additional 3 patients with bronchogenic carcinoma, however, were diagnosed only by brush biopsy. Fluoroscopy was essential for accurate positioning of the biopsy instrument. Increased risk factors were present in 83 patients (51 per cent), among whom the immunosuppressed group presented special problems. Significant bleeding in 15 patients (9 per cent) was controlled by conservative management. Pneumothorax occurred in 7 patients (4 per cent). There were no deaths. Transbronchial forceps lung biopsy in experienced hands is safe and well tolerated. The physician, nevertheless, must be prepared to handle major complications, especially bleeding. The procedure has a resonable diagnostic yield in high-risk patients who have a variety of lung lesions.

Adolescent↗
PubMed1976

Pulmonary hemorrhage in fiberoptic transbronchial biopsy.

Transbronchial forceps biopsy via the flexible fiberoptic bronchoscope is described as a "safe," high-yielding procedure, but the potential danger of serious hemorrhage is of concern to chest physicians. In a collected series of 438 patients, the incidence of mild to "explosive" hemorrhage was 9 percent in "routine" cases, 29 percent (eight) in 31 immunosuppressed patients, and 45 percent (five) in 11 uremic patients. One death resulted from massive hemorrhage. A new "wedge" method of transbronchial forceps biopsy is now being utilized in our bronchoscopic unit. The tip of the flexible fiberoptic bronchoscope is lodged into the appropriate segmental bronchus to tamponade any bleeding and, thus, prevent blood from flooding the airway. Careful screening of patients and competence in procedural techniques are necessary. Otherwise, transbronchial forceps biopsy should be performed through a rigid open-tube bronchoscopicronchoscope or performed through a rigid open-tube bronchoscope or lung tissue should be obtained via thoracotomy.

Arrhythmias, Cardiac↗
PubMed1976

Hypoxic protection in paraquat poisoning.

Ingestion or injection of the herbicide paraquat (1,1'-dimethyl-4,4'-dipyridylium dichloride) has caused more than 120 deaths in humans. Most have been due to respiratory failure caused by pulmonary edema, hemorrhage, and atelectasis, or subsequent pulmonary fibrosis. Paraquat is concentrated in lung tissue and is believed to cause superoxide radical formation in the presence of oxygen and suitable electron donors. Exposure to increased concentrations of oxygen has been reported to accelerate the toxicity of paraquat. The therapeutic efficacy of a reduced oxygen environment was investigated by exposing paraquat-poisoned mice to 10% oxygen after stepwise drops from 14% oxygen. Sixty-one mice were given intraperitoneal injections of 27 mg. per kg. of paraquat. The 25 mice in hypoxia for 7 days had a 32% mortality rate versus a 78% mortality rate for the remainder of the mice in room air, p less than 0.01. After a dose of 20 mg. per kg. of paraquat administered intraperitoneally, 24 mice in hypoxia had a 25% mortality rate versus 51% for 35 animals in room air. Brief exposures of the hypoxic group to "normoxia" (room air) led to pulmonary edema and death. The continuous exposure of paraquat-poisoned animals to hypoxic environments was protective. This approach may be useful in other oxidant lung injuries.

Animals↗
PubMed1975

Light and immunofluorescent study of the Arthus reaction in the rabbit lung.

A localized Arthus reaction was produced in the lung of sensitized rabbits by delivery of antigen into a lower lobe bronchus using a method of selective bronchial catheterization under fluoroscopy. The rabbits were sensitized with bovine immunoglobulin G (B-IgG) in incomplete Freund's adjuvant (IFA) to produce precipitating antibody without classic delayed hypersensitivity. Pulmonary histopathology was studied at intervals following antigen challenge, using light and immunofluorescent microscopy. Gross lesions peripheral to the lower lobe bronchus receiving antigen were found within 12 hr. Subsequent necrosis resulted in a dense scar by 6 wk. Microscopically, early lesions were typified by localized bronchitis, bronchiolitis, alveolitis, and vasculitis with exuberant exudates containing predominantly polymorphonuclear leukocytes. Extensive focal necrosis was present by 72 hr. Immunofluorescent studies revealed the presence of B-IgG, rabbit IgG, and complement (C3) in and around bronchi, bronchioles, alveoli, and vessels. No granulomatous lesions were found, and proliferation of alveolar lining cells was not detected in these studies. Thus, the lung can participate in an acute Arthus reaction following local antigen challenge in systemically sensitized animals. The pathology more closely resembles a necrotizing bacterial pneumonia than an interstitial or hypersensitivity pneumonitis under the conditions of this experimental system. Implications for human disease are speculative.

Animals↗
PubMed1975

Diagnostic fiberoptic bronchoscopy: Techniques and results of biopsy in 600 patients.

Six hundred patients underwent diagnostic flexible fiberoptic bronchoscopy (FFB). The two diseases most frequently encountered were bronchogenic carcinoma in 330 patients (55 percent) and bacterial infection in 94 (16 percent). A positive cytology on biopsy material was obtained in 279 of 330 patients (85 percent) with primary lung cancer. Fluoroscopy was a valuable aid in diagnosing bronchogenic carcinoma, since 42 percent of the tumors were not visible endoscopically and required fluoroscopic control for placement of the biopsy instrument. Of the 55 patients with hemoptysis and negative chest x-ray films, nine (15 percent) had fiberoptically visible endobronchial carcinomas! In addition, two patients with carcinoma of the larynx and one with carcinoma of the nasopharynx were discovered. Transbronchial biopsy (TBB) in 68 patinets with diffuse and localized disease achieved an overall 69 percent diagnostic success, including a correct diagnosis in each of four patients with Pneumocystis carinii pneumonia. Brush biopsy provided additional valuable laboratory data in bacterial, mycobacterial and cytomegalovirsu infectious but had a poor yield in Pneumocystis infection. Complications as a result of forceps biopsy were minimal, except for brisk bleeding in six patients.

Adenocarcinoma, Bronchiolo-Alveolar↗