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Biomedical subjects

L Wilson

Publications and source records attributed to L Wilson.

At least 289 records · Page 16Linked to original sources
PubMed1988

Methods used to improve gamete efficiency.

Male factor infertility accounts for a significant percentage of problems in infertile couples. With clinical utilization of the technologies for selection of good-quality spermatozoa from the ejaculate, our ability to successfully treat the severely affected male factor couple has improved. However, it must be remembered that even with current technologies, fertilization success is reduced in these patients but remains above a 50% level. Other factors that can be used in the future to improve on these statistics are being investigated in regard to the in vitro environment for gametes, that is, the type of culture medium, the methods of coincubation of the sperm and egg, and other methods of enhancement of sperm fertilizing potential. However, methods of sperm preparation will achieve improvement in a percentage of these males treated, and can be used to improve fertilization and pregnancy success. It is important to understand the limitations of the zona-free hamster test, but it is also important to use that test as a screening method for sperm handling. By utilizing the SPA to select out the optimal method of sperm preparation, the fertilization and pregnancy outcome can be improved. Overall, the live-birth rate in male factor infertile couples is lower than non-male-factor couples treated by IVF and GIFT. Until more is known about basic spermatozoal function, and the ability to improve that function in affected males, the live-birth rate should not be expected to change substantially.

Cell Separation↗
PubMed1988

Immunologically measured serum markers and their role in the management of prostate cancer.

Serum prostatic acid phosphatase and prostate-specific antigen have been measured in a group of 106 cases of newly diagnosed prostate cancer. The serum levels of the tumour markers have been correlated with the clinical and ultrasound staging of the prostate cancer at diagnosis. All patients were managed by a deferred treatment policy. Patients without detectable metastases at presentation have been assessed after a period of 2 years to determine if the level of serum tumour markers at diagnosis could predict subsequent disease progression. The study has demonstrated that a combination of immunologically measured acid phosphatase and prostate-specific antigen is the best method of assessing the prognosis of an individual prostate cancer at the time of presentation.

Acid Phosphatase↗
PubMed1988

Nursing: a major hospital cost component.

Selected studies of nursing costs demonstrate a wide variation per patient-day and per patient stay within the same DRG. These differences could reflect either actual differences in nursing practice or methodological differences in calculating practice costs. We examined several alternative methods to find hospital nursing costs of the same group of patients. Measures of patient illness--AS-SCORE severity of illness, Relative Intensity (RIMs), MacLeod nursing intensity, and a per diem measure--were compared for variations in nursing cost. Various definitions of nursing cost itself also were compared using the same patients. Two approaches to defining nursing cost elements--by nursing unit and by hands-on patient care-are discussed. Several nursing cost studies reporting data for DRG 121 (myocardial infarction with complications and/or comorbidity) were compared with our data. The nursing care costs in several studies of these same patients varied from $706 to $1,778 per stay (a 60 percent difference); reasons for these cost differences are discussed. It is suggested that at least part of this variability reflects methodological differences. Cost data should be reported carefully to facilitate comparisons with the results of other studies. Efforts should begin toward designing nursing cost studies using comparable measures and cost-finding methodologies.

Costs and Cost Analysis↗
PubMed1988

Velopharyngeal incompetence as the presenting symptom of myotonic dystrophy.

Velopharyngeal incompetence has previously been described in the late stages of myotonic dystrophy. However, we have seen three cases in which velopharyngeal incompetence was the presenting symptom. Despite different ethnic backgrounds, the patients shared a similar appearance, all three had the characteristic "myopathic facies," mandibulomaxillary disproportion, muscular weakness, and positive family history. Identifying a progressive neuromuscular disorder as the cause of velopharyngeal incompetence has important treatment and prognostic implications. Based on the experience described in this report, we feel that the velopharyngeal incompetence of the myotonic patient might best be managed nonsurgically.

Adolescent↗
PubMed1987

Isolation of a conserved sequence deleted in Duchenne muscular dystrophy patients.

We have isolated a DNA sequence (HIP25) by subtraction- hybridisation which is deleted in a number of Duchenne muscular dystrophy (DMD) patients. HIP25 is conserved in evolution and hybridises to human fetal and adult muscle mRNA. HIP25 is absent in human fetal fibroblast mRNA. Physical mapping data localise this sequence within Xp21 between the breakpoints of X;autosome translocations found in two females suffering from the disease. HIP25 is a candidate exon sequence for the basic defect in DMD boys deleted at this locus.

Adult↗
PubMed1987

Why is there a left side underestimation in rod bisection?

Subjects set the extremities of a horizontal rod to appear equidistant from a central reference point, with or without central fixation. On either side, the contrast (salience) of the rod against the background was high or low. Extents to the left were set smaller than those to the right, an effect (LSU) which was stronger with central fixation, indicating that both hemispatial and anatomical pathway factors contribute. Reduced salience on the left increased rather than decreased the LSU, indicating the importance of attentional factors.

Adult↗
PubMed1987

Effects of progesterone withdrawal on uterine prostaglandin levels in the ovariectomized pregnant rat.

Prostaglandin (PG) levels increase dramatically just before parturition in the rat. Coincident with this dramatic increase in uterine PGs is a precipitous decrease in plasma progesterone and enhanced plasma estradiol levels. The purpose of the present study was to mimic the progesterone withdrawal phenomenon in the presence and absence of estradiol in ovariectomized pregnant rats and determine the effects on uterine PGF, PGE, thromboxane B2 (TxB2) and 6-keto-PGF1a (6KF) levels. Rats were ovariectomized on day 16 of pregnancy and silastic inserts containing progesterone and estradiol placed s.c. in two groups of rats (I and II) while the third group (III) received progesterone only. On day 19 of pregnancy progesterone was withdrawn from groups II and III and rats sacrificed 0, 6, 12 and 24 hours later. Uterine tissue was assayed for PGs by radioimmunoassay. Progesterone withdrawal in the absence of estradiol (III) administration significantly (p less than .05) elevated PGE, TxB2 and 6KF, but not PGF, at the 24 hour period compared to controls (I). When progesterone was withdrawn in the presence of exogenously administered estradiol (II) only PGF showed enhancement (p less than .05) over III at the 24 hour period thus indicating a specific effect of estradiol on the PGF metabolic pathway. In conclusion, these data indicate that: (1) progesterone withdrawal is a potent stimulus for uterine PG production and is probably a major contributor to the augmented uterine PGE, TxB2 and 6KF levels at term in the pregnant rat; and (2) progesterone withdrawal in the presence of exogenously administered estradiol enhances uterine PGF production thus indicating a specific effect of estradiol on PGF production.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

The effect on human neuroblastoma spheroids of fractionated radiation regimes calculated to be equivalent for damage to late responding normal tissues.

Multicellular tumour spheroids (MTS) are a useful in vitro model of human cancer. An experiment was designed to assess the likely therapeutic advantage of hyperfractionation--a proposed strategy in radiotherapy. A cell line (NB1-G) derived from human neuroblastoma was grown as MTS. This MTS line is radiosensitive with low capacity for repair of sublethal radiation damage. These properties make NB1-G a suitable line to test the theoretical advantage of hyperfractionation. MTS were irradiated using alternative fractionated regimens, with fraction sizes varying from 0.5 to 4 Gy. In each experiment, the total dose was chosen to make the regimens theoretically isoeffective for damage to late-responding normal tissues (calculated using the linear-quadratic mathematical model with alpha/beta = 3 Gy). The radiation responses of MTS were evaluated using the end-points of regrowth delay and "proportion cured". Regimens using smaller doses per fraction were found to be markedly more effective in causing damage to neuroblastoma MTS, as assessed by either end-point. These experimental findings support the proposal that hyperfractionation should be a therapeutically advantageous strategy in the treatment of tumours whose radiobiological properties are similar to those of the MTS neuroblastoma line NB1-G.

Cell Line↗
PubMed1987

Pregnancies following in vitro fertilization and ultrasound-directed surgical embryo transfer by perurethral and transvaginal techniques.

Ultrasound-directed surgical ET is useful in patients with a history of difficult cervical (nonsurgical) transfer, and was performed without complications in the small group reported here. The technique is straightforward, and requires no greater expertise than that necessary for ultrasound-guided oocyte collection. However, further studies are necessary to assess its role in the routine transfer of embryos following IVF.

Adult↗
PubMed1987

Biological properties of a tumour cell line (NB1-G) derived from human neuroblastoma.

The properties of a new tumour cell line (NB1-G) derived from human neuroblastoma by xenografting in nude rats followed by adaptation to tissue culture are described. Studies using a panel of monoclonal antibodies demonstrate the neuro-ectodermal nature of the cells and support the diagnosis of the primary tumour as neuroblastoma. Cytogenetic studies have revealed a human karyotype with several chromosomal abnormalities. Genetic analysis by in situ DNA hybridization has demonstrated the presence of multiple copies of the N-myc gene. Approximately 20-30 fold amplification of the gene is observed on Southern blot analysis. The cell line has been adapted to growth as multicellular tumour spheroids as well as monolayer culture. Radiobiological studies on spheroids show the cells to be radiosensitive with low capacity for sub-lethal damage accumulation and repair. The cell line should be useful for fundamental studies of human neuroblastoma as well as experimental therapy in vitro.

Animals↗
PubMed1987

Lithium clearance in man: effects of dietary salt intake, acute changes in extracellular fluid volume, amiloride and frusemide.

1. The effects of amiloride and frusemide on lithium clearance were studied during changes in dietary sodium chloride intake and during infusion of 0.9% NaCl in normal human volunteers. 2. Lithium and fractional lithium clearances were less on the low than on the high salt diet. Values for the medium salt diet were intermediate. Acute extracellular fluid volume expansion with 0.9% NaCl infusion and extracellular fluid volume contraction 3-4 h after intravenous frusemide caused lithium and fractional lithium clearances to increase and decrease respectively. 3. Amiloride caused small changes in lithium and fractional lithium clearances on a low salt diet, but was without effect when salt intake was medium or high. 4. Increases in lithium clearance occurred immediately after frusemide irrespective of dietary salt intake and in subjects infused with 0.9% NaCl. Only in salt-depleted subjects did frusemide cause a substantial increase in fractional lithium clearance. Changes induced under other circumstances were small. 5. It is concluded that the lithium clearance method for assessment of proximal tubule salt and water reabsorption can be used with some degree of confidence in certain circumstances (medium and high salt intake as well as in acute volume expansion) but may not be reliable when dietary salt intake is low.

Adult↗
PubMed1987

Kinesin is associated with a nonmicrotubule component of sea urchin mitotic spindles.

Sea urchin embryos in second division have been lysed into microtubule-stabilizing buffers to yield mitotic cytoskeletons (MCSs) that consist of two mitotic spindles surrounded by a cortical array of filaments. Microtubules have been completely extracted from MCSs by incubation at 0 degrees C with Ca2+-containing buffer. An antibody to the microtubule translocator kinesin stains the spindles in MCSs and in MCSs treated with 5 mM ATP and also stains spindle-remnants of the MCSs after the microtubules have been extracted. We conclude that kinesin binds to a nonmicrotubule component in the mitotic spindle. Based on these results, we present several models of kinesin function in the spindle.

Animals↗
PubMed1987

Phase dynamics at microtubule ends: the coexistence of microtubule length changes and treadmilling.

The length dynamics both of microtubule-associated protein (MAP)-rich and MAP-depleted bovine brain microtubules were examined at polymer mass steady state. In both preparations, the microtubules exhibited length redistributions shortly after polymer mass steady state was attained. With time, however, both populations relaxed to a state in which no further changes in length distributions could be detected. Shearing the microtubules or diluting the microtubule suspensions transiently increased the extent to which microtubule length redistributions occurred, but again the microtubules relaxed to a state in which changes in the polymer length distributions were not detected. Under steady-state conditions of constant polymer mass and stable microtubule length distribution, both MAP-rich and MAP-depleted microtubules exhibited behavior consistent with treadmilling. MAPs strongly suppressed the magnitude of length redistributions and the steady-state treadmilling rates. These data indicate that the inherent tendency of microtubules in vitro is to relax to a steady state in which net changes in the microtubule length distributions are zero. If the basis of the observed length redistributions is the spontaneous loss and regain of GTP-tubulin ("GTP caps") at microtubule ends, then in order to account for stable length distributions the microtubule ends must reside in the capped state far longer than in the uncapped state, and uncapped microtubule ends must be rapidly recapped. The data suggest that microtubules in cells may have an inherent tendency to remain in the polymerized state, and that microtubule disassembly must be induced actively.

Animals↗
PubMed1987

Clinical neurological examination, neuropsychology, electroencephalography and computed tomographic head scanning in active amateur boxers.

Twenty active amateur boxers were studied seeking evidence of neurological dysfunction and, if present, the best method for detecting it. Seven of these boxers had an abnormal clinical neurological examination, eight an abnormal EEG and nine of 15 examined had abnormal neuropsychometry. The CT scan was abnormal in only one. An abnormal clinical examination correlated significantly (p less than 0.05) with an increasing number of fights, and an abnormal EEG with decreasing age (p less than 0.05). In several of the neuropsychometric tests, the boxers were significantly worse than controls (p less than 0.05). Neuropsychometry was the best method for detecting neurological dysfunction.

Adolescent↗
PubMed1987

A neuropsychological study of active amateur boxers.

Neuropsychological examinations were carried out on 29 amateur boxers and 19 controls matched for age, ethnicity, and education. There was no evidence of significantly impaired performance in the boxers. Within the boxing group, a variety of features of boxing history were examined as possible predictors of cognitive performance (such as number of knockouts, duration of boxing). No feature was a significant predictor of lower cognitive performance.

Adolescent↗