Search PubMed⌕ Search

Biomedical subjects

W L Johnson

Publications and source records attributed to W L Johnson.

At least 55 records · Page 3Linked to original sources
PubMed1989

Improving feeding systems for sheep in a Mediterranean rain-fed cereals/livestock area of Morocco.

In rain-fed cereal-producing areas of Morocco, stubble and straw from barley and wheat and forage grazed from fallow lands are important feeds for sheep. Supplementation to maintain BW of ewes pregnant while grazing stubble, methods to improve utilization of straw, annual forage legumes to complement grazing of fallow land, and by-product feeds in diets for weaned lambs have been tested in collaborative research trials. Pregnant ewes grazing cereal stubble for 10 to 12 wk at a modest stocking rate and unsupplemented, or at a heavier stocking rate and supplemented after 5 wk, gained about 3 kg; most of the gain occurred in wk 1 to 4 due to intake of residual scattered grain. Following the stubble-grazing period (coincident with late gestation), straw plus an energy supplement alone resulted in low lamb birth weight and survivability. Urea treatment increased N content of straw and holds potential. After the onset of winter rains, self-reseeding annual legume (Medicago spp.) pastures allowed lactating Timahdit ewes to gain 4 kg during 90 d postpartum. Their suckling lambs gained 260 g/d, thus doubling the weight of lamb weaned per ewe compared with those grazing unimproved fallow. Confined growing lambs fed diets with 40% sugarbeet pulp or 20% carob meal gained more than 200 g/d, reducing the time needed to reach market weight. These results demonstrate that marked improvements in performance and efficiency of sheep in Mediterranean rain-fed cereal/livestock systems are possible using locally available resources.

Animal Feed↗
PubMed1989

Transposition of the posterior tibial tendon.

The posterior tibial tendon was rerouted by the technique described by Baker and Hill in 35 feet of children with a dynamic varus deformity due to spastic cerebral palsy. The average follow-up period was 11.4 years. In ten of the feet, rerouting of the posterior tibial tendon was the only procedure performed. Eight of the ten feet obtained a satisfactory correction. There were no overcorrection problems in these ten feet. In the remaining 25 feet, the Baker-Hill procedure was done concurrently with other procedures, such as lengthening of the triceps surae (22 feet), calcaneal osteotomy (two feet), or plantar fascia release (two feet). The dynamic equinovarus deformity was corrected in all 25, but three subsequently developed a cavus deformity. This was probably caused by excessive weakening of the triceps surae rather than transposition of the posterior tibial tendon. Based on this study, anterior rerouting of the posterior tibial tendon seems to be a simple, safe, and generally effective procedure for correction of dynamic varus of the spastic hindfoot in children with cerebral palsy.

Adolescent↗
PubMed1988

"High-risk" percutaneous transluminal coronary angioplasty.

Of 6,500 percutaneous transluminal coronary angioplasty procedures performed between June 1980 and June 1987, 3,501 (1,604 single lesion and 1,897 multiple lesion) were performed in "low-risk" patients with a procedure-related mortality of 0.2 to 0.3%. In comparison, several clinical variables were identified that increased procedural risk by up to 50-fold. These factors include left main dilatation (n = 103, mortality 3.9%), left main equivalent dilatation (n = 77, mortality 2.6%), ejection fraction less than or equal to 40% (n = 664, mortality 2.7%), age greater than or equal to 70 years (n = 1,038, mortality 1.4%), dilatation of all 3 vessels (n = 305, mortality 1.3%), combined diagnostic catheterization and angioplasty for unstable angina (n = 193, mortality 1.5%), and percutaneous transluminal coronary angioplasty for acute myocardial infarction (n = 446, mortality 8.5%). Important considerations in the selection and management of these high-risk patients are discussed.

Age Factors↗
PubMed1988

Hugging balloons: coronary angioplasty of oversized vessels with side-by-side balloons.

Angioplasty of large (greater than 4.0-mm) saphenous vein grafts using the largest available (4.0-mm) balloon catheters may result in inadequate graft dilatation. To avoid leaving a significant residual stenosis, two balloon catheters can be inflated side by side across the stenosis. Herein, we report two cases where this "hugging balloon" technique was used to achieve wide graft patency.

Angioplasty, Balloon↗
PubMed1988

Application of percutaneous transluminal coronary angioplasty to the internal mammary artery graft.

Between June 1982 and August 1987, 45 patients underwent percutaneous transluminal coronary angioplasty within the internal mammary artery graft (group 1) or had coronary angioplasty performed beyond the graft insertion with the internal mammary artery used as a conduit (group 2). Previous coronary artery bypass surgery was performed at a mean of 29.8 months (range 2 to 199) in group 1 and 51.3 months (range 2 to 134) in group 2. Sixteen (62%) of 26 patients in group 1 and 17 (71%) of 24 patients in group 2 had multivessel angioplasty; multilesion angioplasty was performed in 20 patients (77%) in group 1 and in 19 patients (79%) in group 2. Within group 1, 12 (37.5%) of 32 lesions were in the body of the internal mammary artery graft and 20 lesions (62.5%) occurred at the distal anastomosis. Angioplasty was successful in 30 (94%) of 32 attempts in group 1 and in 25 (96%) of 26 attempts in group 2. Procedure-related complications were limited to emergent bypass surgery in one patient in group 2. At a mean follow-up period of 12.7 months in group 1 and 18.2 months in group 2, 39 (90%) of the 45 patients had no or only mild angina. There were two late cardiac deaths (mortality rate 4.9%) in the 41 patients with successful angioplasty. The results of this study demonstrate that percutaneous transluminal coronary angioplasty of internal mammary artery grafts combined with multilesion angioplasty is technically feasible, can be performed with a high primary success rate and a low incidence of complications and achieves sustained clinical improvement in the majority of patients.

Adult↗
PubMed1988

Selection among nonlinear models for rate of passage studies in ruminants.

Eight Toggenburg wether goats were fed either Coastal bermudagrass (Cynodon dactylon) or orchardgrass (Dactylis glomerata)-alfalfa (Medicago sativa) hay (57:43%) in a reversal design. Four markers were used to study the movement of different digesta fractions: erbium for large particles greater than 1,700 microns; ytterbium for medium particles less than 1,700 microns and greater than 500 microns; chromium for small particles less than 500 microns and greater than 32 microns; and cobalt to follow liquid passage. Fecal samples were collected every 4 h for 6 d. The excretion curves obtained for every marker in each animal were used for model selection. One-compartment gamma age-dependent models (gamma 2, 3 and 4 age-dependent), two-compartment (gamma 2 and gamma 3 age-dependent, age-independent) models and a biexponential model were fitted to the data. Residual sums of squares and the Davidson and MacKinnon test were used to select the most appropriate models. These procedures indicated that the models best describing the movement of different digesta fractions through the gastrointestinal tract of goats, in this experiment, were the biexponential model for liquids, gamma 2 two-compartment model for small and medium particles and gamma 3 two-compartment model for large particles. To accurately describe the behavior of different components of digesta in the digestive tract, different mathematical models are required. In general, models that describe the movement of large particles have higher orders of age-dependency than models that describe the passage of liquids or small particles.

Animal Feed↗
PubMed1986

Spectrum of IgG2 subclass deficiency in children with recurrent infections: prospective study.

Serum immunoglobulins and IgG subclasses were measured in 30 children with recurrent infections. Seven patients had low IgG2 concentrations (less than 3SD below the geometric mean for age). Four of these seven patients had normal concentrations of IgG, IgA and IgM, and thus would have been considered immunologically normal by routine criteria. The seven children with IgG2 deficiency had more severe infections than the 23 children with normal IgG2. Five children had recurrent pneumonia or sinusitis, one had recurrent invasive Haemophilus influenzae type b infections, and one had severe pneumococcal meningitis. Their immunologic abnormalities were heterogeneous. Two children had isolated IgG2 deficiency, two had IgG2-IgG4 deficiency, one had IgG2-IgG4-IgA deficiency, one had IgG2-IgA deficiency, and one had severe IgG1-IgG2 deficiency with abnormal T cell function and thrombocytopenia. Thus IgG2 deficiency occurs frequently among children with recurrent infections, and is associated with a variety of clinical and immunologic abnormalities.

Adolescent↗
PubMed1986

Utilization of sodium from sodium bicarbonate by broiler chicks.

Two experiments were performed with broiler chicks housed in battery brooders to ascertain their response to low levels of dietary sodium, supplied by either sodium chloride or sodium bicarbonate, and to compare the utilization of sodium from the materials. In each experiment, three replicate pens containing seven female day-old chicks were offered each treatment for a 21-day feeding period. Sodium chloride levels of 0, .05, .10, .15, or .20% were a portion of the dietary treatments. Additional groups received the same basal supplemented with .072, .144, or .216% sodium bicarbonate in the first experiment and .072 or .144% during the second, in order to provide sodium levels comparable to those resulting from .05, .10, or .15% sodium chloride. Group body weights, water consumption, feed consumption, and manure moisture served as evaluation criteria. As the level of sodium chloride was increased, body weights, feed and water intake, and manure moisture also increased. In neither experiment were there significant differences between the body weights of birds receiving sodium bicarbonate and those resulting from feeding comparable levels of sodium from sodium chloride. Average daily feed and sodium intake also did not differ statistically between groups receiving comparable sodium from either source. Water intake tended to be somewhat higher for sodium bicarbonate treatments and was significantly so for the .144% sodium bicarbonate treatment of the second experiment. Manure moisture was somewhat variable and did not differ statistically between sources at the same sodium level. It is concluded that the sodium from sodium bicarbonate was utilized in a manner comparable to that from sodium chloride.

Animals↗
PubMed1985

Association of asthenozoospermia with a deficiency of a seminal glycoprotein.

Two major glycoprotein bands (Rf 0.67 and 0.49) were detected with polyacrylamide disc gel electrophoresis in normal human semen, spermatocele fluid and prostatovesicular fluid. The most rapidly migrating band (Rf 0.67) was either present in only trace amounts or absent in asthenozoospermic semen. The protein moiety of this glycoprotein was present in normal and asthenozoospermic semen, but it was not glycosylated in asthenozoospermic semen. It is suggested that there is a relationship between this glycoprotein and the acquisition of sperm motility.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

Percutaneous transluminal coronary angioplasty with and without thrombolytic therapy for treatment of acute myocardial infarction.

Successful percutaneous transluminal coronary angioplasty (PTCA) was performed during evolving acute myocardial infarction (AMI) in 41 patients. Catheterization was performed within 1 hour of presentation, from 1 to 12 hours (mean 3.3) following symptom onset. In 17 of 29 patients with a totally occluded coronary artery, successful thrombolytic therapy was followed by PTCA of a residual high-grade atheromatous stenosis. Successful PTCA without prior thrombolytic therapy was employed in 11 of 12 subtotal coronary stenoses producing acute infarction syndromes and in two patients having critical coronary stenoses not immediately responsible for AMI. Three patients experienced early in-hospital reocclusion with reinfarction. One death occurred in a patient presenting with cardiogenic shock. All remaining patients had prompt pain relief, subsequent stable clinical courses, and no clinical or late angiographic evidence of coronary reocclusion. Dramatic improvement of regional and global left ventricular function was evident in 22 of 27 patients undergoing late left ventricular angiography. At follow-up, 94% of patients remained free of angina although three required repeat dilatation of recurrent stenoses. We concluded that PTCA may be performed with or without thrombolytic therapy in selected patients with AMI and may reduce the likelihood of late reocclusion following successful thrombolytic therapy.

Adult↗
PubMed1981

Ultradian rhythms in stereotyped and self-injurious behavior.

Institutionalized profoundly mentally retarded persons who exhibited stereotyped motor movements, including self-injurious behavior, were observed continuously in their typical environments for periods of 8 to 14 hours on each of several days. In addition to targeting stereotyped responses, we collected data pertaining to activities, settings, other behavioral states, and social interactions. Spectral and cross-spectral analyses were conducted on data from each daily session. Power spectra indicated a marked ultradian or less than 24-hour rhythm for each subject on each day. Spectral density estimates were thought to reflect the influence of rhythmic changes in the institutional environment and, to a less degree, the influence of an endogenous rest--activity rhythm.

Adolescent↗