C. Ian Hood

The effects of irradiation on the eye and optic nerve

Abstract Late effects of irradiation of the eye and optic nerve in 74 patients are reviewed. Time-dose analyses are performed for lacrimal apparatus, retinal, and optic nerve injuries. Management of radiation complications is discussed. Recommendations are made regarding radiation treatment techniques and methods of reducing the risk of late injury.

Antacid Pulmonary Aspiration in the Dog

The amount of damage resulting from pulmonary aspiration of gastric contents is determined primarily by the acidity of the aspirate. Thus, it has been recommended that the pH of stomach contents of pregnant women be increased by the oral administration of antacids prior to anesthesia for delivery. T

An Evaluation of Steroid Therapy in Aspiration Pneumonitis

Endotracheal instillation of 0.1 N HCl in 19 anesthetized dogs caused a severe pulmonary reaction that resulted in hypoxia, hypercarbia, metabolic acidosis, hemoconcentration and death in 80 per cent of the animals. The resultant pulmonary damage was not altered morphologically or physiologically by high (30 mg/kg), low (0.3 mg/kg), or multiple (30 mg/kg every 8 hours for three days) doses of methylprednisolone administered intravenously.

Steroid Therapy for Pneumonitis Induced in Rabbits by Aspiration of Foodstuff

The instillation of gastric contents, 0.5 ml/kg (pH 4.3), containing small food particles into the left diaphragmatic lobe of the lungs of 49 rabbits caused severe aspiration pneumonitis. Administration of methylprednisolone, 30 mg/kg, intramuscularly, every eight hours for three days to 26 of the 49 rabbits did not alter the rate of roentgenographic resolution of the pneumonitis. Corticosteroids did decrease the fibroblastic response of the lung to the aspirate, but also interfered with healing of granulomatous lesions.

Pulmonary lavage with liquid fluorocarbon in a model of pulmonary edema.

An animal model of a specific type of acute pulmonary edema was produced by instilling a concentrated sucrose solution into each mainstem bronchus of 20 dogs. The resulting disease was treated with either 100 per cent oxygen via fixed-volume ventilation with PEEP at 10 cm H2O (control group), or pulmonary lavage with oxygenated Caroxin-D fluorocarbon liquid for one hour followed by reconversion to breathing 100 per cent oxygen by mechanical ventilation with PEEP. More edema fluid was recovered during the washout period (22.8 ± 8 ml/kg) than during the corresponding time in the control group (14.2 ± 10 ml/kg). The washout group also had a significantly higher and more prolonged elevation in Pao2 than the control group. Pulmonary lavage with fluorocarbon in the treatment of acute, massive pulmonary edema appeared beneficial and warrants further study.

Oxygenation by ventilation with fluorocarbon liquid (FX-80).

Thirty-six mongrel dogs were ventilated with oxygenated fluorocarbon liquid (FX-80) for an hour and then reconverted to breathing gaseous oxygen. For several days after breathing this liquid, the dogs were hypoxemic while they breathed air. The authors attributed this to residual fluorocarbon in the lung and/or partial airway closure. By ten days after liquid ventilation, Pao2s had returned to pre-experimental control levels. Pathologic examination of the lungs three hours after termination of liquid ventilation disclosed an acute exudative inflammatory reaction largely confined to the bronchioles. By 72 hours the acute reaction had subsided and the dominant change consisted of vacuolated intra-alveolar macrophages, presumably containing fluorocarbon. At ten days, macrophages were still present, but generally in much smaller numbers; after a month only scattered small groups were found. At 18 months the lungs were normal.

Corneal amyloidosis associated with keratoconus.

Nodular, gray-white, central corneal opacities which extended from the subepithelial zone through the anterior four fifths of the stroma developed in a 50-year-old man with a longstanding history of hard contact lens wear for keratoconus. Results of histopathologic analysis of the corneal button obtained at the time of penetrating keratoplasty disclosed that the opacities were composed of amyloid. Corneal amyloidosis is rarely found in association with keratoconus. Although there were some similarities in the pattern of amyloid deposition to that seen in primary familial amyloidosis of the cornea, the authors believe that their patient is more likely to have had a secondary amyloidosis. Corneal amyloidosis should be considered in keratoconus patients with development of unusual forms of central corneal opacification.

Pulmonary Function after Ventilation with Fluorocarbon Liquid (Caroxin-D)

To determine whether animals can breathe fluorocarbon liquid and then be reconverted to breathing air without permanent alterations in lung function or structure, 32 mongrel dogs were anesthetized and ventilated for an hour with Caroxin-D fluorocarbon liquid. In all animals arterial blood-gas tensions were measured and pH determinations made serially. In 16 dogs, pulmonary resistance, compliance, and VD/Vx were measured before and repeatedly after liquid ventilation. During ventilation with Caroxin-D, adequate arterial oxygen tensions were maintained; Pco2 increased and pH decreased, returning to normal immediately after reconversion to breathing gas. A decrease in pulmonary compliance was found 24 hours after ventilation with fluorocarbon, but this value returned to normal within 72 hours. Po2s 24 hours after ventilation with Caroxin-D were significantly higher than in previous studies with FX-80. Surviving animals were followed for at least a year, after which time normal pulmonary function was found. The authors conclude that dogs can be ventilated with Caroxin-D fluorocarbon briefly with return to normal lung function for at least a year, even though residual fluorocarbon remains in the lung after a year.

Solitary Eosinophilic Granuloma of the Lateral Orbital Wall

Two children (aged 18 and 23 months at the initial examinations) were each ultimately found at surgery to have a solitary eosinophilic granuloma of the lateral orbital wall. Both patients had a symptomatic period of six weeks during which time other diagnoses were considered: bacterial preseptal cellulitis and mumps dacryoadenitis in the first case and traumatic recurrent orbital hematoma in the second. Diagnostic difficulties stemmed from confusing features in their histories, as well as the location of the lesion and the deceptively minimal swelling relative to the actual size of the lesion. Follow-up ten and 18 months after curettage of the two lesions showed no recurrence or evidence of systemic involvement. Although most reported cases describe the orbital frontal bone as the site of origin in the orbit, our cases demonstrated that unifocal eosinophilic granuloma may occur in the lateral wall of the orbit.

Development of hypertension in rats treated with aldosterone acetate

Abstract Chronic (10 week) administration of graded doses of d-aldosterone acetate (10, 20, or 40 μg/day) to unilaterally nephrectomized, saline-treated rats increased both their systolic blood pressure and heart weight above the level observed for controls. Thus, doses of aldosterone within the physiological range (2–25 μg/100 g body weight per day) can induce hypertension in “sensitized” rats. Administration of the same doses for the same length of time to intact rats in a second experiment induced smaller rises in blood pressure and no significant cardiac hypertrophy. A sigmoid relationship was observed between the ratio of thyroid weight to body weight and arbitrary ranges of systolic blood pressure for all rats to which aldosterone was administered chronically. Thyroid weight ratio first increased significantly when systolic blood pressure rose to levels of 160–169 mm Hg. The maximal increase in thyroid weight was 25–30% above that of untreated controls. The sigmoid relationship suggests that an unidentified, primary factor elevates blood pressure to the threshold range without thyroid mediation but when the threshold range of blood pressure is exceeded, thyroid weight increases and may mediate further elevation of blood pressure. Hence, the thyroid gland may play a secondary role in the development of aldosterone-induced hypertension. Administration of 1.1 μg d-aldosterone acetate/100 g body weight per day had no effect on the elevated blood pressure of rats whose kidneys were bilaterally encapsulated with latex envelopes. However, administration of 3.0 μg d-aldosterone acetate/100 g body weight per day to rats whose kidneys were recently bilaterally encapsulated with latex envelopes accelerated the rate of elevation of systolic blood pressure. Thus, small doses of aldosterone can accelerate the development of renal hypertension in rats.