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Biomedical subjects

J Lehman

Publications and source records attributed to J Lehman.

29 records · Page 2Linked to original sources
PubMed1979

Electrical stimulation in exercise of the quadriceps femoris muscle.

Thirty-seven healthy subjects took part in an investigation to determine if the application of electrical stimulation to normal muscle, in combination with exercise, augments strength. Subjects were divided into three groups. Grwoup A (n = 14) was a control group (no exercise, no electrical stimulation). Group B members (n = 11) engaged in 10 sessions of maximum isometric exercise, and Group C subjects (n = 12) performed 10 sessions of maximum isometric exercise while simultaneously receiving electrical stimulation. The knee extensor muscles of subjects in Groups B and C increased in strength. However, the strength gains for Groups B and C were equivalent, suggesting that electrical stimulation combined with maximum isometric contractions has no greater effect on enhancing strength than does conventional static exercise.

Adult↗
PubMed1979

Cell wall lysin as a component of the bacteriophage phi 6 virion.

Cell wall lytic activity was found in particles of the lipid-containing bacteriophage ø6. The activity can be extracted from the virion with Triton X-100 in the presence of salt. This treatment removes the membrane-like envelope of the virion which includes five proteins. The lysin requires detergent for in vitro activity. Virus particles formed in nonsuppressor cells by several classes of ø6 nonsense mutants contained the lysin activity; however, particles formed by a mutant (unable to make proteins P5 and P11) had very low activity; high activity was produced when particles were formed in a suppressor host. A study of the time course of the appearance of the lysin during infection showed that it appeared and increased in cells infected with wild-type virus and in suppressor cells infected with a mutant of class 511, but it did not increase in nonsuppressor cells infected with the class 511 mutant. It is concluded that protein P5 is a component of the lysin and that the role of its activity is in both early and late stages of infection. In particular, the lysin may be necessary for the passage of the infecting core of the virion through the cell wall of the bacterium, as well as in the final lysis necessary for the liberation of progeny phage. A mutant of the virus that produces a larger-than-normal protein P10 does not induce normal lysin activity in host Pseudomonas phaseolicola HB10Y, although it does in strain ERA Pseudomonas pseudoalcaligenes. This indicates that protein P5 is probably not sufficient for lysin activity, but the nature of the interaction between P5 and P10 is unknown.

Bacterial Proteins↗
PubMedDate not supplied

Imaging evaluation of suspected pulmonary embolism.

Venous thromboembolism (VTE) is a common disorder that is difficult to diagnose clinically but carries significant morbidity and mortality if untreated. Additionally, although demonstrated to be of benefit in cases of proven deep vein thrombosis (DVT) and pulmonary embolism (PE), anticoagulation therapy is not without risk. Because the clinical exam is known to be unreliable for the detection of both DVT and PE, many imaging modalities have been used in the diagnostic imaging algorithm for the detection of VTE, including chest radiography, ventilation/perfusion (V/Q) scintigraphy, pulmonary angiography, and recently, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Chest radiographic findings in acute PE include focal oligemia, vascular enlargement, atelectasis, pleural effusions, and air space opacities representing pulmonary hemorrhage or infarction. The chest radiograph can occasionally be suggestive of PE but is more often nonspecifically abnormal. The main use of the chest radiograph in the evaluation of suspected PE is to exclude entities that may simulate PE and to assist in the interpretation of V/Q scintigraphy. Lower extremity venous compression ultrasonography (CU) is both sensitive and specific for the diagnosis of femoropopliteal DVT, and the value of negative CU results has been established in outcomes studies. However, the reliability of CU for the detection of isolated calf vein thrombosis is not well established, and the clinical significance of such thrombi is debatable. Additional methods such as color and spectral Doppler analysis are also useful in the diagnostic evaluation of DVT but are best considered as adjuncts to the conventional CU examination rather than as primary diagnostic modalities themselves. Compression ultrasonography and Doppler techniques are useful in the evaluation of suspected upper extremity DVT; spectral Doppler waveform analysis is particularly useful to assess for the patency of veins that cannot be directly visualized and compressed with conventional gray-scale sonography. V/Q scintigraphy has been the initial modality obtained in patients suspected of PE for a number of years. Although many studies have investigated the role of V/Q scintigraphy in the evaluation of VTE, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has provided the most useful information regarding the utility of V/Q scintigraphy in this setting. A high probability scan interpretation is sufficient justification to institute anticoagulation, and a normal perfusion scan effectively excludes the diagnosis of PE. A normal/near normal scan interpretation also carries a sufficiently low prevalence of angiographically proven PE to withhold anticoagulation. Although the prevalence of PE in the setting of low probability scan interpretations is low and several outcomes studies have demonstrated a benign course in untreated patients with low probability scan results, patients with inadequate cardiopulmonary reserve do not necessarily have good outcomes. Such patients deserve more aggressive evaluation. Patients with intermediate probability scan results have a 20% to 40% prevalence of angiographically proven PE and thus require further investigation. The radionuclide investigation of DVT includes such techniques as radionuclide venography and thrombus-avid scintigraphy. Although these methods have not been as thoroughly evaluated as CU, studies thus far have indicated encouraging results, and further investigations are warranted. Pulmonary angiography has been the gold standard for the diagnosis of PE for decades. Studies have indicated that angiography has probably been underutilized by referring physicians for the evaluation of suspected PE, likely because of the perception of significant morbidity and mortality associated with the procedure. (ABSTRACT TRUNCATED)

Algorithms↗
PubMedDate not supplied

Postoperative cellulitis of the foot and lower leg following coronary bypass.

Greater saphenous vein grafts are standardly used for coronary artery bypass grafting. Recurrent acute cellulitis of the saphenous vein-donor extremity is an infrequently reported complication. The authors present a protocol designed to reduce the incidence of the recurrent cellulitis through proper preoperative assessment and postoperative management.

Cellulitis↗