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Biomedical subjects

R Cabot

Publications and source records attributed to R Cabot.

6 recordsLinked to original sources
PubMed2001

Translocation of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro.

The distribution of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro was revealed by using MitoTracker Green staining and confocal laser scanning microscopy. The regulation of mitochondrial translocation by microfilaments and microtubules was also studied. In oocytes collected from small follicles, strong staining of active mitochondria was observed in the cell cortex. Accumulation of active mitochondria in the peripheral cytoplasm and around the germinal vesicles was characteristic of fully grown oocytes collected from large follicles. Mitochondria accumulated in the perinuclear area during meiotic progression from germinal vesicle breakdown (GVBD) to anaphase I. Larger mitochondrial foci were formed and moved to the inner cytoplasm in mature oocytes. Compared with the oocytes matured in vivo, in which large mitochondrial foci were distributed throughout the cytoplasm, mitochondria were not observed in the central cytoplasm in most of the oocytes matured in vitro. Strong staining of mitochondria was observed in the first polar bodies in metaphase II oocytes. In fertilized eggs, active mitochondria aggregated in the pronuclear region. Perinuclear clustering and a cortical ring were the most marked features of early cleavage. Active mitochondria were distributed in both inner cell mass cells and trophectoderm cells of the blastocysts. Disassembly of microtubules with nocodazole inhibited both mitochondrial aggregations to the germinal vesicle area and their inward movement to the inner cytoplasm during oocyte maturation, as well as the translocation of mitochondria to the peri-pronuclear region during fertilization, whereas disruption of microfilaments by cytochalasin B had no effects. These data indicate that: (i) oocyte maturation, fertilization and early embryo development in pigs are associated with changes in active mitochondrial distribution; (ii) mitochondrial translocation is mediated by microtubules, but not by microfilaments; and (iii) in vitro maturation conditions may cause incomplete movement of mitochondria to the inner cytoplasm and thus affect cytoplasmic maturation.

Actin Cytoskeleton↗
PubMed1992

Abdominal rectopexy for complete prolapse: prospective study evaluating changes in symptoms and anorectal function.

The effect of abdominal rectopexy on bowel function is difficult to assess in retrospective studies because preoperative bowel habit cannot be determined accurately. This study examined bowel symptoms and physiologic tests of anorectal function prospectively in 23 patients before and at three months after rectopexy. Rectopexy eliminated complete prolapse in all and stopped bleeding in 16 of 18 patients. Incontinence improved significantly. Constipation (less than 3 bowel actions per week or straining for more than 25 percent of defecation time) was relieved in 4 of 11 affected patients but developed in 5 of the 12 who were not constipated preoperatively. Since the median bowel frequency was 21 motions per week before surgery and 17 afterward, the main determinant of constipation was straining. Abdominal pain was relieved after rectopexy in 6 of 12 patients but developed in 3 of 13 who were pain-free before surgery. Three patients (13 percent) had a first-degree relative with rectal prolapse. Perineal descent decreased significantly. Maximal anal resting pressure increased significantly, but this did not correlate significantly with improved continence. Twenty-one patients (91 percent) could expel a 50-ml balloon preoperatively; 18 of those 21 could still do so postoperatively. The two patients who could not expel the balloon preoperatively were able to do so postoperative. This study shows that rectal prolapse is associated with profoundly abnormal defecation and abdominal pain. While abdominal rectopexy improved continence, it may improve or worsen other bowel symptoms, including constipation.

Abdominal Pain↗
PubMed1989

Motor and functional recovery after stroke: accuracy of physical therapists' predictions.

The degree to which physical therapists correctly predicted motor and functional outcome for stroke patients was investigated. Therapists used an adapted form of the physical therapy portion of the Patient Evaluation Conference System (PECSc)--a 14-item assessment measured on an 8-point scale. At admission to a rehabilitation hospital, therapists performed initial assessments of seven motor and functional items on 204 patients and assigned goal scores; before discharge the patients were reevaluated and their final scores determined. The accuracy by which therapists correctly predicted the final score ranged from 53% to 67%; therapists were accurate to within one score for 80% to 83% of patients. The only determinant of accuracy was initial score; neither patient characteristics (age, side of lesion) nor staff experience were found to be associated with correctly predicting final score. Sensitivity and specificity of the goals for predicting independence were examined for three items: lying to sitting, ambulation, and stairs. The sensitivity of a goal of independence was high (96% to 100%), indicating that those patients who were independent at discharge were correctly identified by therapists at admission. The predictive value of a goal of dependence was also very high (91% to 100%), indicating that patients predicted to remain dependent did so. These results suggest that therapists' predictions could prove useful in screening patients for rehabilitation and in planning treatment strategies.

Aged↗
PubMed1989

Hepatic resection for secondary tumours.

The role of liver resection for secondary tumours is reviewed, with particular reference to secondary disease from primary colorectal cancer. While there are no controlled trials producing direct evidence of improved survival following resection, figures on five year survivors without resection are anecdotal. Numerous series now report five year survival of up to 50% following resection, instances of five year survival without resection are now fallen to around 5% in most major series. Factors which adversely affect survival after resection seem to be poor tumour clearance, number of metastases and possibly Dukes' C primary tumours. Other factors, including the extent of resection and size of the tumour, may affect perioperative morbidity and mortality but should not influence long-term survival. Resectional treatment is rapidly gaining an established position in the treatment of colorectal secondaries, and may be considered also for some non-colorectal lesions, particularly endocrine tumours.

Colorectal Neoplasms↗