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Biomedical subjects

L Scott

Publications and source records attributed to L Scott.

At least 271 records · Page 15Linked to original sources
PubMed1995

Use of postseparation sperm parameters to determine the method of choice for sperm preparation for assisted reproductive technology.

OBJECTIVE: To evaluate strict sperm morphology after preparation of semen specimens using three different sperm separation techniques, since strict morphology correlates well with IVF. DESIGN: Semen from 30 men were analyzed before and after sperm separation using mini-Percoll gradient, direct swim-up, and SpermPrep filtration column (ZBL, Inc., Lexington, KY) methods. SETTING: Assisted Reproductive Technology laboratory at Sinai Hospital of Baltimore. MAIN OUTCOME MEASURES: Primary end points measured were percent morphologically normal sperm and percent improvement in sperm morphology, using Kruger strict criteria. Secondary factors determined were percent motility, improvement in motility, hypoosmotic swelling, improvement in hypoosmotic swelling, and 24- and 48-hour sperm survival under simulated IVF conditions. RESULTS: Mini-Percoll produced specimens with significantly greater normal sperm morphology, morphology improvement, motility, hypoosmotic swelling, and survival than obtained with the other two separation methods. For 25 of 30 specimens, mini-Percoll yielded the greatest number of morphologically normal, motile sperm that survived for 24 hours. In four instances, mini-Percoll was associated with an increased percentage of acrosomal abnormalities despite an overall improvement in morphology. Hypoosmotic swelling scores were lower in two subjects after mini-Percoll sperm separation and in three subjects for each of the other methods. CONCLUSIONS: Data suggest that mini-Percoll is superior to swim-up or SpermPrep for producing specimens with enhanced morphology, motility, and in vitro survival. However, no single separation technique is always superior, and methodology may induce damage to the acrosome or sperm membranes. Sperm specimens should be evaluated individually to determine the best separation method before actual ART cycles. The technique that yields the most morphologically normal, motile sperm that survive in culture should be used for ART procedures.

Cell Separation↗
PubMed1995

Confirmation of the safety of autologous blood donation by patients awaiting heart or lung transplantation. A controlled study using hemodynamic monitoring.

BACKGROUND: Though earlier investigations have demonstrated the efficacy of autologous blood transfusion in reducing allogeneic blood exposure in patients undergoing heart or lung transplantation, questions remain regarding the safety of blood donation by patients with severe heart or lung disease. METHODS: Response to autologous blood donation by candidates for heart and lung transplantation and a group of age- and gender-matched control subjects was studied. Heart rate, blood pressure, oxygen saturation, and cardiac rhythm were examined before and after phlebotomy, and response to orthostatic challenge was evaluated. Patients were also questioned regarding impressions of changes in subjective sense of well being. Differences between patients and control subjects were evaluated by the paired t test and Fisher's exact test. An alpha of 0.05 was used in all testing to determine statistical significance. RESULTS: Eighteen candidates for heart transplantation, 16 candidates for lung transplantation, and their matched control subjects were studied. Though patients and control subjects differed with respect to baseline hemodynamic measurements, significant differences between the groups' responses to phlebotomy were not observed. After whole blood donation, orthostatic challenge resulted in a mean change in mean arterial pressure of -2.1 mm Hg in candidates for heart transplantation compared with a mean of +3.6 mm Hg in their control subjects (p = 0.062). In candidates for lung transplantation there was a mean change of +2.2 mm Hg after orthostatic challenge versus a mean change of +8.5 mm Hg in their control subjects (p = 0.052). Furthermore, no changes in cardiac rhythm or arterial oxygen saturation were detected. CONCLUSIONS: The hemodynamic effects of autologous blood donation in a group of patients with significant cardiac or pulmonary disease were not different from those observed in patients considered acceptable candidates for autologous blood collection. On the basis of these objective findings, we believe that patients with less severe degrees of heart or lung disease should not be excluded from participation in autologous blood donation programs.

Blood Transfusion, Autologous↗
PubMed1995

Phenylalanine-stimulated secretion of cholecystokinin is calcium dependent.

The secretion of cholecystokinin was examined in STC-1 cells, an intestinal cholecystokinin (CCK)-secreting cell line. Exposure to the amino acid L-phenylalanine increased release of CCK by 135%, 180%, and 251% of control levels after 15-min treatments with 5, 20, and 50 mM phenylalanine, respectively. L-Phenylalanine-induced secretion of CCK was inhibited by the calcium channel blocker diltiazem (10 microM). L-Phenylalanine (20 mM) also significantly increased cytosolic calcium levels in fura 2-acetoxymethyl ester (fura 2-AM)-loaded cells, and this increase was diltiazem sensitive. D-Phenylalanine, over the dose range of 5-50 mM, produced nonsignificant increases in CCK release. Treatment of STC-1 cells with 300 ng/ml of pertussis toxin for either 4 or 24 h did not significantly affect either basal release of CCK or L-phenylalanine-stimulated secretion. Patch-clamp recordings from cell-attached membrane patches showed a stimulation in calcium channel activity after L-phenylalanine. These results indicate that, in STC-1 cells, L-phenylalanine stimulates release of cholecystokinin via a calcium-dependent process.

Animals↗
PubMed1995

Aging and dietary modulation of elastase and interleukin-1 beta secretion.

Aging is associated with diminished immune function that may stem from alterations in arachidonic acid metabolism and lipid peroxidation. This study sought to determine if dietary modification of fatty acids influenced neutrophil and monocyte secretion after an in vivo inflammatory stress in older human subjects. Volunteers participated in protocols that forced their quadriceps muscles to lengthen during tension development (eccentric stress). These protocols can cause inflammatory foci in the muscle as well as alterations in circulating leukocyte function. In this study, in vivo neutrophil degranulation was assessed by plasma elastase concentrations, and mononuclear cell function was assessed by interleukin-1 beta (IL-1 beta) secretion in vitro. In response to eccentric stress, older subjects (> 60 yr old) taking a placebo had no apparent elastase response, whereas those taking fish oil supplements responded with a 142% increase in plasma elastase (P = 0.011), similar to responses of younger reference subjects (< 33 yr old) taking no supplement. Overall, elastase responses correlated with individual plasma arachidonic acid-to-eicosapentaenoic acid ratios (r = -0.881, P = 0.004). Thus apparent age-related differences in elastase release were reconciled by individual differences in fatty acid nutriture. No significant temporal changes in urinary lipid peroxide excretion or IL-1 beta secretion were observed; however, age-associated differences were found.

Adult↗
PubMed1995

Endometrial biopsy dating. Interobserver variation and its impact on clinical practice.

To determine the degree of interobserver variation and the level of correlation in endometrial biopsy (EB) interpretation, five pathologists interpreted 30 EBs randomly selected from all EBs performed according to standard criteria. An EB was considered out of phase (OOP) if there was greater than a two-day lag in histologic development relative to the onset of the next menstrual period. Interobserver variation among the five pathologists was 0.85 and 0.82 days for one- and two-day dating ranges, respectively. Coefficients of correlation for histologic interpretation ranged from 0.839 to 0.934 (P < .0001). Seventy percent to 74% of the time all five pathologists agreed that a given EB was in phase or OOP. The low interobserver variation and high correlation between observers further validates the EB as a diagnostic test. However, up to 30% of the time a clinical management decision may be altered depending upon who interprets the EB. Thus, even with low interobserver variation, the clinical consequence of small changes in EB interpretation may be significant.

Biopsy↗
PubMed1995

Clinical indicators: a methodological approach.

Clinical indicators offer physiotherapists a tool by which quality of care can be flagged and evaluated. Such a flag requires a measure of the cost of treatment as well as the outcome achieved for that cost. Traditionally, the number of treatments to discharge has been used as a proxy measure of cost as well as outcome of physiotherapy care. However, physiotherapists recognize that the cost of treatment is an inappropriate reflection of the outcome of care in many instances. The challenge for physiotherapists in developing clinical indicators is to set appropriate flags of quality of care. This paper presents a methodological approach to the development of a flag of performance for acute lower back pain.

Acute Disease↗
PubMed1995

Human sperm motility-enhancing agents have detrimental effects on mouse oocytes and embryos.

OBJECTIVES: To test the artificial activating properties of the human sperm motility-enhancing agents pentoxifylline, caffeine, 2-deoxyadenosine, and cyclic adenosine 3':5' monophosphate (cAMP) on mouse oocytes and determine if the agents exhibit an inhibitory effect on in vitro development of mouse embryos. DESIGN: CD-1 mouse oocytes were exposed to 1, 2.5, 5, or 10 mM pentoxifylline, caffeine, 2-deoxyadenosine, or cAMP for 10, 30, or 60 minutes and their activation and development was scored over 96 hours of culture. A 10% ethanol solution and aging unstimulated oocytes served as controls. Pronuclear embryos from CD-1, CF-1, and B6C3 F1 hybrid mice were cultured in 0.16, 0.33, 0.66, 1.25, 2.5, 5.0, or 10 mM of pentoxifylline, caffeine, 2-deoxyadenosine, or cAMP and development was scored over 96 hours of culture. RESULTS: Exposure to pentoxifylline, caffeine, and 2-deoxyadenosine, but not cAMP, artificially activated mouse oocytes in a concentration- and exposure time-dependent manner. The level of activation was significantly greater than that associated with oocyte aging but less than ethanol-induced activation. Agent-activated oocytes had limited developmental capacity compared with the ethanol-activated oocytes. Pentoxifylline and 2-deoxyadenosine were more toxic than caffeine, especially at the higher concentrations and after prolonged exposure. All of the agents affected embryo development in a dose-dependent manner with developmental inhibition and embryotoxicity that was often not evident until after one to three cell cycles. CONCLUSIONS: Pentoxifylline, caffeine, 2-deoxyadenosine, and cAMP have adverse effects on mouse oocytes or embryos at concentrations commonly used to activate sperm in human IVF. Therefore, care should be taken to minimize the exposure of human oocytes and embryos to these agents until their direct effects have been investigated more fully.

Animals↗