Biomedical subjects

P D Warren

Publications and source records attributed to P D Warren.

5 recordsLinked to original sources

PubMed2000

Does axial limb rotation affect the alignment measurements in deformed limbs?

The long-term outcome of total knee arthroplasty and femoral or tibial osteotomy is related to the ability of the surgeon to achieve the desired alignment based on preoperative planning. This study evaluates the effect of axial rotation on measured tibiofemoral angles and the angle formed between the anatomic and mechanical axes of the femur in lower extremities with valgus and varus deformities. A comparison study of the measured tibiofemoral angles indicated a statistically significant effect in models with severe vagus or varus deformity when rotated 10 degrees internally or externally. In the second part of the study, the measured angle between the anatomic and mechanical axes of the femur never varied by more than 1 degree, despite a 40 degrees are of rotation. The results of the study indicate the tibiofemoral angle measurements are more sensitive to axial limb rotation in lower extremities with valgus or varus deformity than are normally aligned limbs. In preoperative planning of total knee arthroplasty, the measured angle between the anatomic and mechanical axes of the femur is less effected by limb rotation, regardless of the degree of valgus or varus deformity.

Arthroplasty, Replacement, Knee↗

PubMed1997

Fractures in very low birth weight infants with rickets.

A syndrome in very low birth weight premature infants weighing less than 1500 g is evidenced by developmental nutritional rickets and fractures at 75 days of age. In a review conducted over 42 months, 247 very low birth weight cases were identified. Rickets was diagnosed in 96 (39%) infants whose mean age was 50 days and fractures were diagnosed in 26 (10.5%) infants whose mean age was 75 days. These 26 infants experienced 98 fractures: 10 humerus, 13 radius, 8 ulna, 4 metacarpal, 3 clavicle, 54 ribs, 5 femur, and 1 fibula. Risk factors included hepatobiliary disease, total parenteral nutrition, diuretic therapy, physical therapy with passive motion, and chest percussion therapy. With early recognition, metabolic therapy and splinting, not casting, are appropriate treatments.

Diuretics↗

PubMed1985

Developmental variability within and between mouse expanding blastocysts and their ICMs.

We have attempted to reduce the developmental heterogeneity amongst populations of mouse blastocysts by synchronizing embryos to the first visible signs of blastocoel formation. Using embryos timed in this way, we have examined the extent of variation of inside and outside cell number and of inside cell size, nuclear DNA content and developmental potential, between and within embryos of a similar age postcavitation. The overall impression gained is one of wide heterogeneity in inside:outside cell number ratios and in cell cycling and its relation to cavitation among embryos of similar age postcavitation. However, the simplest explanation of our results suggests that cavitation generally begins at a time when most outside cells are in their sixth developmental cell cycle and that outside cells, as a population, are a little ahead of inside cells in their cell cycling. Additionally we present evidence that, within at least some individual inner cell masses (ICM), there is intraembryo variation in the time at which inside cell developmental potential becomes restricted.

Animals↗

PubMed1984

Trophectodermal processes regulate the expression of totipotency within the inner cell mass of the mouse expanding blastocyst.

Mouse blastocysts, aged 0, 2, 6 and 12 h from the onset of cavitation, were examined by transmission (TEM) and scanning (SEM) electron microscopy. In TEM sections, trophectoderm cells (TE) differed morphologically from those of the inner cell mass (ICM) by their flattened shape, paler cytosol staining and polarized disposition of both junctional complexes (apicolateral) and intracellular secondary lysosomes (SL; basal). Throughout this period of development, cytoplasmic processes, characterized by abundant SLs, cover approximately 80% of the juxtacoelic face of the ICM. These processes are shown to be derived from the basal surface of TE cells intermediately placed between polar and mural regions. In SEM preparations of the juxtacoelic ICM surface, revealed by 'cracking open' blastocysts, the processes appear as tongue-shaped, centripetally oriented structures which terminate collectively at a central area on the ICM surface. The potential of cultured ICMs to generate TE was demonstrated following their immunosurgical isolation from blastocysts aged up to 12 h post cavitation and by examining the sequence of ultrastructural changes associated with TE generation by ICMs from 2 h blastocysts. In contrast, the juxtacoelic cells of similarly aged ICMs observed in situ in ultrasections of intact embryos showed little or no evidence of totipotency expression as judged by the absence of TE characteristics. Since TE expression within presumptive ICM cells is thought to be generated by an asymmetry of cell contacts (Johnson & Ziomek, 1983), we propose that the juxtacoelic TE processes, by providing a cellular cover to the ICM, function in suppressing the expression in situ of ICM totipotency.

Animals↗

PubMedDate not supplied

Complications after posterior spinal fusion in Duchenne's muscular dystrophy.

Patients with Duchenne's muscular dystrophy often develop progressive scoliosis. Should spinal stabilization be necessary, these patients are considered at high risk for surgically related complications. This retrospective study of 30 patients with Duchenne's examined the prevalence and types of complications associated with posterior spinal fusion and determined the percentage of patients who lived > or = 2 years beyond surgery. Major complications related to cardiopulmonary compromise, infection, or hardware complications occurred in 27%, and minor complications occurred in another 16%. Seventy-seven percent of the patients lived > or = 2 years beyond their surgery. The majority of patients and their families, including half of those who had major complications, reported that surgery resulted in an improvement in their quality of life. Although complications are common, the benefits realized by the patient with Duchenne's muscular dystrophy with scoliosis reinforce the importance of surgical stabilization.

Adolescent↗