Structural aberrations in T-even bacteriophage VIII. Surface morphology of T4 Lollipops

The surface of canavanine-induced T4B and T4D giant phages was investigated with the electron microscope using freeze-etching and shadow casting methods. On the relatively smooth surface of the elongated phage heads, a left-handed helical arrangement of subunits of about 4.0 to 4.5 nm diameter was found with interhelical distances ～6.7 nm and an angle of 15°, measured normal to the long axis of the particle. These helices were the most obvious; they were intercepted at about 60° by two other lattice lines, one of 75° relative to the equator, the other one at an angle of 45°. Both of these lattice lines were about equally spaced but of lesser definition than the first helix. This “smooth” surface pattern changed drastically after exposure of the phage to temperatures between 42 and 48° for 10 to 60 min; the interhelical distance then measured 11.1 ± 0.4 nm, and “capsomeres” of 7.0 to 7.4 nm diameter became visible, producing a rather coarse hexameric lattice. No significant change in the angles between the lattice lines was observed. During storage of suspensions of the “smooth” phage at 2 to 4°, most virus surfaces had assumed the “coarse,” 11.1 nm arrangement. By employing acrylamide electrophoresis, we found that the heat treatment releases a protein with molecular weight of about 11,000. Lollipops of T2L, a phage lacking a capsid protein of similar size, revealed an ill-defined but “coarse” lattice which did not change after heat treatment.     

Attenuation of exercise conditioning by low dose beta-adrenergic receptor blockade

Because it has been shown that high doses of propranolol (40 to 80 mg orally, four times daily) markedly attenuate cardiovascular response to exercise training in healthy subjects, the effects of lower doses of this nonselective beta-adrenergic receptor antagonist on the conditioning response were investigated. Twelve normal men underwent maximal treadmill testing before and after a 6 week intensive exercise program. After an initial test, six men were randomized in a paired fashion to receive low dose propranolol and the others received no drug. The average propranolol dose +/- standard error was 22 +/- 4 mg four times daily, and the average decrease in maximal heart rate due to propranolol was 32 +/- 4 beats/min. Both groups trained at comparable intensities. At the end of the training period, propranolol was stopped and testing was repeated so that the effect of beta-receptor blockade was no longer present but the training effects still persisted. Maximal oxygen consumption increased in control subjects from 47.5 +/- 1.1 to 51.4 +/- 0.4 ml/kg per min (p less than 0.05) but was unchanged in those receiving propranolol (47.2 +/- 1.9 versus 47.4 +/- 1.5). Exercise duration increased in both groups but the increment was greater in the control group (+2.4 versus +1.1 min, p less than 0.05). It is concluded that low level beta-receptor blockade attenuates cardiovascular conditioning in normal subjects in exercise training programs. High levels of sympathetic stimulation during training appear to be important, if not essential, to the conditioning process.     

Complications of tube thoracostomy for acute trauma

Closed tube thoracostomy is a common and very useful procedure in therapy of acute thoracic injury. However, it is not without risk. With aggressive use of this procedure in the emergency department, the incidence of technical complications was 1 percent. Our review suggests that complications can be further diminished by the routine use of large thoracostomy tubes that are placed well up on the chest after confirmation of an open pleural space, by avoiding the use of a trocar for tube placement, and by the use of a high volume, low pressure suction system. Empyema was the most common complication associated with tube thoracostomy after trauma. It occurred in 2.4 percent of the patients. Its exact cause is not known, and the role of prophylactic antibiotics needs to be established.     

Palmar arthroplasty for the treatment of the stiff swan-neck deformity

Palmar arthroplasty for the treatment of the stiff swan-neck deformity in rheumatoid arthritis is designed to correct the mechanical block to flexion that is caused by palmar plate adhesions (which obliterate the retrocondylar recess) and by collateral ligament contracture and adhesions. This procedure can be performed at the same time as correction of the primary cause of proximal interphalangeal joint (PIP) hyperextension (e.g., intrinsic tightness or flexor tenosynovitis) and can also be supplemented with superficialis tenodesis to minimize recurrent hyperextension. Postoperative flexor dynamic traction, which is started at 24 to 48 hours and continued for a minimum of 3 to 4 weeks, is critical to the maintenance of motion. Arthroplasty in 47 PIP joints in 14 hands of 9 patients demonstrate an increase in motion from +20 degrees hyperextension and 9.5 degrees flexion to -7 degrees extension and 72 degrees flexion postoperatively.     

Effect of estrogens on the uterine blood flow of oophorectomized ewes

Quantitative information about dilatation of uterine blood vessels after administration of estrogens is needed, e.g., the dose response of uterine blood flow to estrogens, whether different estrogens are equipotent in inducing vasodilation, the maximum obtainable blood flow to the nonpregnant uterus under maximum estrogen stimulation, and the related chain of biochemical events. The type of biological preparation developed and the results obtained thus far form the substance of this report.     

Complications of assisted ventilation. A prospective study of 354 consecutive episodes

Three hundred fourteen consecutive patients were studied prospectively during 354 episodes of assisted ventilation in a 5 month period. These patients ranged in age from 15 to 95 years, and ventilatory support was required for from 1 hour to 54 days. Over-all survival was 64 per cent. Eighteen complications were studied prospectively, of which three (intubation of the right mainstem bronchus, endotracheal tube malfunction and alveolar hypoventilation) were associated with decreased survival. Four hundred individual complications or potential complications were observed. Intubation of the right mainstem bronchus was associated with alveolar hyperventilation, atelectasis and/or tension pneumothorax in a significant number of cases (all, P < 0.001). The onset of pneumonia, pneumothorax, atelectasis, gastric distention and ventilator malfunction all were observed during assisted ventilation, but none was associated with increased mortality. Careful attention to the recognition and prevention of complications, especially those associated with endotracheal intubation, is mandatory in all patients treated with assisted ventilation.     

External irradiation in treatment of papillary carcinoma of the thyroid

A retrospective review of thirty patients with papillary carcinoma of the thyroid with metastatic or direct extension of their disease was undertaken. These thirty patients were treated by a standard surgical procedure and postoperative high dose orthoirradiation with an average twenty-one year follow-up period. Results of this treatment are compared with those of eighty similar patients treated by surgery alone.The primary treatment of papillary carcinoma of the thyroid remains surgical but with a consideration that irradiation may be of benefit in certain instances.