An improved method for the analysis of xenon-133 washin and washout curves

A method is described for analysis of xenon-133 washin and washout curves, in the presence of a slowly varying background. The method uses least-squares fitting of a single exponential together with a quadratic function to correct for the background. The method has been applied both to simulated data and to data from 25 patients. The accuracy in the relevant lung parameters was 5% over a wide range of the specific ventilation. A comparison is made with other methods in use to measure regional lung-function parameters. Our method produces reliable results even when specific ventilation is low, which can occur in patients with chronic airflow obstruction, where other methods may incur errors of more than 45%.     

Presidential address: American Society for Surgery of the hand

Tape recordings of time-compressed (40 and 60%) monosyllables were administered to 11 patients with diffuse unilateral temporal lobe lesion, 4 hemispherectomy patients, and 16 patients with discrete unilateral temporal lobe lesion. Time compression was accomplished with the Fairbanks electromechanical apparatus, which allowed temporal compression but did not introduce frequency distortion. The results revealed that with 60% time compression, all patients with diffuse unilateral cortical lesion showed breakdown of speech discrimination in the ear contralateral to the lesion. Patients with discrete unilateral cortical lesion generally did not demonstrate breakdown with the 60% time-compressed materials.     

Morphological and physical basis for lung surfactant action

An abhesive or 'anti-glue' function for lung surfactant is proposed which is reconcilable with the known unfolding of alveolar walls at low lung volumes. The theory is developed based upon the fact that the work required to part wetted surfaces is directly proportional to the surface tension. Application of the concept of the spreading coefficient from surface physical chemistry S = gammata-(gamma lla + gamma lle), where the gamma's refer to the surface (interfacial) tensions among the tissue (t), air (a) and lining layer (ll) surface, is shown to explain qualitatively physiological data in lungs subjected to maneuvers with working fluids varying widely in surface tension and spreading properties.     

Diagnosis of ostechondritis dissecans of the femoral condyles: the value of the lateral x-ray view

The lateral X-ray view of the knee is more likely to yield the diagnosis of osteochondritis dissecans of the femoral condyles if the examiner is aware that most cases are located in the subarticular bone of the medial femoral condyle between two lines: The first extended anteriorly from the density of the roof of the intercondylar notch, and the second, extended distally from the posterior cortex of the distal femoral diaphysis.     

Expression of a renal type I sodium/phosphate transporter (NaPi-1) induces a conductance in Xenopus oocytes permeable for organic and inorganic anions

Two distinct molecular types (I and II) of renal proximal tubular brush border Na+/Pi cotransporters have been identified by expression cloning on the basis of their capacity to induce Na+-dependent Pi influx in tracer experiments. Whereas the type II transporters (e.g., NaPi-2 and NaPi-3) resemble well known characteristics of brush border Na+/Pi cotransport, little is known about the properties of the type I transporter (NaPi-1). In contrast to type II, type I transporters produced electrogenic transport only at high extracellular Pi concentrations (> or =3 mM). On the other hand, expression of NaPi-1 induced a Cl- conductance in Xenopus laevis oocytes, which was inhibited by Cl- channel blockers [5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) > niflumic acid > 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid]. Further, the Cl- conductance was inhibited by the organic anions phenol red, benzylpenicillin (penicillin G), and probenecid. These organic anions induced outwardly directed currents in the absence of Cl-. In tracer studies, we observed uptake of benzylpenicillin with a Km of 0.22 mM; benzylpenicillin uptake was inhibited by NPPB and niflumic acid. These findings suggest that the type I Na+/Pi cotransporter functions also as a novel type of anion channel permeable not only for Cl- but also for organic anions. Such an apical anion channel could serve an important role in the transport of Cl- and the excretion of anionic xenobiotics.     

Difficult peripheral vascular injuries

Successful management of the difficult peripheral vascular injury requires a multidisciplinary approach. Prompt recognition of the vascular injury and adherence to the recognized principles of vascular repair provide a successful short-term surgical result. The long-term consequences of an injury are determined by the associated orthopedic, soft tissue, and nerve injuries.