Calcium current in motor nerve endings of the lizard.
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Animals↗
Biomedical subjects
J W Moore
Publications and source records attributed to J W Moore.
Clinical management issues in males with sex chromosomal mosaicism and discordant phenotype/sex chromosomal patterns.
The recent availability of Y DNA probes has made it possible to identify two forms of 46,XX male syndrome: Y DNA positive and Y DNA negative. The Y DNA positive male results from a X;Y translocation with a low recurrence risk; the Y DNA negative males are due to a mutation with a high recurrence risk. 46,XX males and mosaic forms are phenotypically indistinguishable. A review of the case histories for 11 individuals indicates that affected males have highly variable genital and nongenital phenotypes. Physical findings may be clearly apparent or nonexistent. With the exception of external genitalia, the basis for this variability is unknown. It may be related to differences in Y chromatin expression as the result of variable inactivation of the X chromosomes, or to the existence of minor deletions or point mutations secondary to an exchange of genetic material. Common and uncommon clinical problems in these individuals require evaluation and follow-up care that is provided through a cooperative, interdisciplinary approach.
Adolescent↗
The mRNAs encoding acidic FGF, basic FGF and FGF receptor are coordinately downregulated during myogenic differentiation.
Acidic and basic fibroblast growth factors (FGFs) are members of a family of proteins that exert pleiotropic effects in a range of cell types including skeletal myocytes. Previous studies demonstrate that exogenously supplied FGFs stimulate proliferation of myoblasts and inhibit their differentiation in culture, but little information is available concerning endogenous expression of FGFs by skeletal myocytes. In this study acidic and basic FGF mRNAs were found to be expressed in murine and rat skeletal muscle, and expression was demonstrated to vary with the tissue and species examined. Myogenic cell lines were then analyzed to determine if FGFs are expressed in myoblasts, and if so, whether expression is regulated during myogenic differentiation. Murine Sol 8 and rat L6 myoblasts were found to express acidic and basic FGF mRNAs, and the expression of both growth factors was downregulated at the transcriptional level during myogenic differentiation. A decrease in expression of the mouse homologue of the human FGF receptor paralleled the decrease in acidic and basic FGF mRNAs in Sol 8 cells, indicating that the decrease in FGF receptor abundance previously observed during myogenic differentiation is regulated at the mRNA level. The results of this study suggest that a coordinate decrease in endogenously produced acidic and basic FGFs and their cognate receptor may participate in the regulation of myogenic differentiation. Furthermore, the observation that expression of a myogenic determination gene, myogenin, increases as FGF transcripts decline, together with previous data demonstrating suppression of myogenin expression by FGF, suggest a mechanism whereby endogenously produced FGFs may exert their effect on differentiation.
Animals↗
Activity of deep cerebellar nuclear cells during classical conditioning of nictitating membrane extension in rabbits.
The activity of neurons in the interposed and dentate nuclei of the cerebellum was investigated during differential classical conditioning of the rabbit eye blink nictitating membrane response. Forty-seven percent of the 165 cells in the study responded to the orbital stimulation used as the unconditioned stimulus (US). The latency distribution of US-elicited responses was bimodal with peaks at 7 and 19 ms. Twenty-one percent of the cells responded with short latencies to the tones used as conditioned stimuli (CSs). These cells typically responded to both the reinforced and nonreinforced CSs. Forty-one percent of the cells responded on conditioned response (CR) trials but not on trials without CRs. The average lead of the neural response to the CR was 71.4 ms. Cells that responded on CR trials were more likely to respond to the CSs, or to the CSs and the US, than cells that did not respond on CR trials. For about half of the cells that responded on CR trials the latency of response followed trial-by-trial variations of CR latency. For the remainder, the response was time-locked to CS-onset. Cells whose responses paralleled the CR may be involved in the initiation or modulation of the CR, while those whose responses were time-locked to the CS may be involved in sensory processing underlying the initiation of the movement. The pathways that may underlie the US- and CS-elicited responses are also discussed.
Animals↗
Results of repeat percutaneous balloon valvuloplasty for pulmonary valvar restenosis.
Follow-up cardiac catheterization studies were used to evaluate 105 patients who had undergone percutaneous balloon pulmonary valvuloplasty. Fifteen of those patients who had peak systolic pulmonary valve gradients greater than = 40 mm Hg at follow-up underwent repeat balloon valvuloplasty. For the initial balloon pulmonary valvuloplasty, the mean ratio of the balloon diameter to pulmonary valve annulus diameter was 0.98 +/- 0.2; at repeat valvuloplasty the mean was 1.19 +/- 0.12. The immediate post-repeat balloon valvuloplasty results showed a reduction in the peak systolic gradient from a mean of 70.2 +/- 17.8 to 29.1 +/- 19.0 mm Hg (p less than 0.001). This reduction in the gradient was maintained at a mean of 14.3 +/- 5.0 mm Hg in 8 of the 10 patients who underwent further follow-up studies. We conclude that successful repeat balloon pulmonary valvuloplasty with the use of larger sized balloons is feasible in patients who have restenosis after the initial percutaneous balloon valvuloplasty--including partial but not complete dysplasia of the pulmonary valve.
Blood Pressure↗
The relationship of free fatty acids with the binding of oestradiol to SHBG and to albumin in women.
Free fatty acid concentration, sex hormone binding globulin (SHBG) concentration, % free oestradiol and % SHBG-bound oestradiol were measured in fasting and non-fasting serum samples from 48 women. Free fatty acids were 128% higher (P less than 0.001) and % SHBG-bound oestradiol was 11% lower (P = 0.001) in fasting than non-fasting samples, but these changes were not significantly correlated (r = -0.16, P = 0.287). Mean SHBG concentration and % free oestradiol did not differ significantly between fasting and non-fasting samples. Between subject correlations were calculated for measurements from 30 premenopausal women: % free oestradiol was inversely correlated with SHBG and free fatty acids and positively correlated with Quetelet's Index; % SHBG-bound oestradiol was positively correlated with SHBG but was not consistently or significantly related to free fatty acids or Quetelet's Index. It was concluded that physiological increases in free fatty acid concentrations do not increase % free oestradiol and that free fatty acids are less important than SHBG concentration and perhaps other variables in determining differences between individuals in oestradiol binding to SHBG.
Adult↗
Growth factor and electrolyte concentration in human breast cyst fluid.
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Adult↗
Foreign body giant cell reaction related to placement of tetracycline-treated polylactic acid: report of 18 cases.
Presented are 18 cases of foreign body giant cell reaction in mandibular third molar extraction wounds previously treated with 40 mg of dry tetracycline powder carried into the wound with a biodegradable polymer dressing. The lesions vary in intensity from local, soft tissue granulomas to osteolytic, central bone pathologies. Several reports of foreign body giant cell reaction to insoluble tetracycline preparations are cited, along with a brief review of the relationship between myospherulosis and various formulations of tetracycline powder in petroleum-based carrier vehicles. The authors suggest that the foreign body giant cell lesions reported here were initiated by micron-sized particles of insoluble tetracycline powder and were further aggravated by certain hydrophobic characteristics of the associated biodegradeable polymer. The authors caution against use of dry, powdered forms of topical antibiotics in fresh dental extraction wounds.
Bone Resorption↗
Hemodynamics and coronary blood flow during experimental aortic valvuloplasty: comparison of the dual versus the single catheter methods.
During thoracotomy 12 anesthetized swine were instrumented and valvuloplasty catheters were positioned at the aortic anulus. Thirty-second occlusions of the left ventricular outflow tract were performed with a single catheter (n = 34) and with simultaneous inflation of dual catheters (n = 47). Left anterior descending coronary artery blood flow fell to minimums of 15% of baseline flow (SD 13.9%) during single balloon occlusion and to 63.8% of baseline flow (SD 22.8%) during dual balloon occlusion. Main pulmonary artery flow fell to minimums of 13.6% of baseline flow (SD 17.3%) during single balloon occlusion and to 66.9% of baseline flow (SD 18.3%) during dual balloon occlusion. Femoral artery systolic pressure dropped to 20.1% of baseline pressure (SD 5.6%) during single balloon occlusion and to 82.6% of baseline pressure (SD 8.1%) during dual balloon occlusion. During single balloon occlusion, 8.5 (SD 3.5) premature ventricular contractions were observed and 2.8 (SD 1.6) premature ventricular contractions occurred during dual balloon occlusion. After deflation of the valvuloplasty catheters, the time to return of baseline flow in the left anterior descending coronary artery was 28.4 second (SD 23.2 seconds) with the single balloon method and 4.8 seconds (SD 3.7 seconds) with the dual balloon method. All of these differences were statistically significant (p less than .001). During occlusion of the left ventricular outflow tract by dual valvuloplasty catheters, there were better hemodynamics, higher coronary blood flows, and fewer premature ventricular contractions than during occlusion by a single catheter. After occlusion by dual catheters, returns to baseline coronary flows were more rapid than after single catheter occlusions. These data may have application to clinical aortic valvuloplasty.
Angiography↗
Testosterone, sex hormone-binding globulin, calculated free testosterone, and oestradiol in male vegans and omnivores.
Total testosterone (T), total oestradiol (E2) and sex hormone-binding globulin (SHBG) concentrations were measured in plasma samples from fifty-one male vegans and fifty-seven omnivores of similar age. Free T concentration was estimated by calculation. In comparison with the omnivores, the vegans had 7% higher total T (P = 0.250), 23% higher SHBG (P = 0.001), 3% lower free T (P = 0.580), and 11% higher E2 (P = 0.194). In a subset of eighteen vegans and twenty-two omnivores for whom 4 d diet records were available, there were statistically significant correlations between T and polyunsaturated fatty acids (r 0.37), SHBG and fat (r 0.43 for total fat, 0.46 for saturated fatty acids and 0.33 for polyunsaturated fatty acids), and SHBG and alcohol (r-0.39). It is concluded that a vegan diet causes a substantial increase in SHBG but has little effect on total or free T or on E2.
Adult↗
Increased expression of fibroblast growth factors in a rabbit skeletal muscle model of exercise conditioning.
Increased tonic contractile activity from exercise or electrical stimulation induces a variety of changes in skeletal muscle, including vascular growth, myoblast proliferation, and fast to slow fiber type conversion. Little is known about the cellular control of such changes, but pleiotropic biochemical modulators such as fibroblast growth factors (FGFs) may be involved in this response and thus may be regulated in response to such stimuli. We examined the regulation of FGF expression in an in vivo model of exercise conditioning previously shown to exhibit vascular growth and fast to slow fiber conversion. FGFs were extracted by heparin-affinity chromatography from extensor digitorum longus muscles of adult rabbits subjected to chronic motor nerve stimulation at 10 Hz. Growth factor activity (expressed in growth factor units [GFUs]) of muscle stimulated for 3 and 21 d was assayed by [3H]thymidine incorporation in 3T3 fibroblasts and compared with that present in the contralateral unstimulated muscle. A small increase in heparin-binding mitogenic activity was observed as early as 3 d of stimulation, and by 21 d mitogenic activity increased significantly when normalized to either wet weight (stimulated, 287 +/- 61 GFU/g; unstimulated, 145 +/- 39 GFU/g) or to protein (stimulated, 5.3 +/- 1.1 GFU/mg; unstimulated, 2.2 +/- 0.6 GFU/mg) (+/- SE, P less than 0.05). Western analysis demonstrated increased amounts of peptides with immunological identity to acidic and basic FGFs in stimulated muscle. The increase in FGF content observed in this study is synchronous with neovascularization, myoblast proliferation, and fast to slow fiber type conversion previously shown in this model. These results demonstrate that increased expression of FGFs is associated with motor nerve stimulation and increased tonic contractile activity of skeletal muscle, and suggests that these proteins may play a regulatory role in the cellular changes that occur during exercise conditioning.
Animals↗
Long term effects of a first pregnancy on serum concentrations of dehydroepiandrosterone sulfate and dehydroepiandrosterone.
A previous paper in this journal reported that first pregnancy was followed by a marked decrease in dehydro-epiandrosterone sulfate (DHAS) and dehydroepiandrosterone (DHA) levels. We report here confirmatory observations from cross-sectional measurements in 460 women. In premenopausal subjects (n = 306), the mean DHAS level was 21% lower (P = 0.005) and the mean DHA level was 32% lower (P less than 0.001) in parous than in nulliparous women. Neither DHAS nor DHA was related to parity in postmenopausal women (n = 154).
Adult↗
Differential importance of hierarchical learning, abstractness, and imagery.
This research examined the relative contribution of hierarchical sequencing, abstractness, and imagery to learning. In the past, hierarchical, logical sequencing was not shown to be superior to other modes of instruction, and the interaction of imagery, abstractness, and sequencing had not been examined, especially regarding the possible superiority of any of these as a contributor to learning. The data were produced by 108 high school students who studied sequences of hierarchically related information arranged in a 2 x 2 x 2 factorial design the dimensions of which varied according to the degree of imagery (high and low), abstractness (abstract and concrete), and type of sequencing (logical and scrambled). Analyses of the amount of learning under these conditions showed that hierarchical sequencing is not only relevant to learning but more related than either imagery or the abstractness of material to be learned. Additional suggestions are made regarding instruction and research especially in relation to matrix rather than hierarchial arrangements of information.
Attention↗
Human immunodeficiency virus.
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AIDS-Related Complex↗
Decision-making processes of youth.
Research supports the theory that after administrators make a decision, feedback, both positive and negative, and also the administrators' perceived security vis-à-vis their position affect their level of commitment to a course of action. However, this research fails to recognize that subjects of college age playing administrators in the simulated, experimental treatments which have been presented in the research had nothing personally to lose if they made a bad decision--an orientation contradictory to the reality of most actual administrative positions. Additionally, the research ignores the interactional effects of the personality of decision makers in terms of their anxiety levels and the judgments they make. This study took both of these considerations into account by creating a decision-making situation within which prospective administrators made monetary commitments to long-term goals while their anxiety level, both as a basic personality attribute and an index of the reality of the decision-making process, was monitored under conditions of varying levels of job insecurity and resistance to their policies in relation to their decisions. Analyses revealed that contrary to the results of past research which used college students as subjects: (1) there is a significant negative correlation between levels of anxiety and commitments to previously chosen courses of action; (2) there are no significant effects of job security on commitment; and, most importantly, (3) high resistance to a policy decision leads to significantly less monetary commitments to long-term goals. The findings suggest that the basis for the contradictory results lies with the anxiety level of decision makers and the realism of experiencing a loss by making poor decisions.
Achievement↗
Partial anomalous pulmonary venous drainage associated with 45,X Turner's syndrome.
Turner's syndrome has well-described associations with congenital heart disease. Up to one third of patients with karyotype 45,X may have coarctation of the aorta. In addition, patients with hypertrophic cardiomyopathy, septal defects, dextrocardia, and anomalous pulmonary venous drainage have been reported anecdotally. Twenty-one consecutive patients with Turner's syndrome were prospectively evaluated. All patients underwent examination by a pediatric cardiologist, electrocardiogram, chest radiograph, and echocardiogram. Three patients with evidence of right ventricular volume overload had cardiac catheterization. Of 12 patients with karyotype 45,X 3 had partial anomalous pulmonary venous drainage with intact atrial septum. One of the 3 also had moderate aortic stenosis. Two additional patients with 45,X had coarctation of the aorta and bicuspid aortic valve, and 4 other patients had minor cardiac defects. Of 9 patients with mosaic karyotype, 1 had a minor cardiac defect. The observations suggest that there may be a significant association of 45,X Turner's syndrome and partial anomalous pulmonary venous drainage.
Adolescent↗
Effects of hippocampal manipulations on the classically conditioned nictitating membrane response: simulations by an attentional-associative model.
The effects of various hippocampal manipulations on the classically conditioned nictitating membrane (NM) response were simulated by a real-time attentional-associative model. The model incorporates: (a) a mechanism capable of establishing associations between conditioned (CS) and unconditioned stimuli (US) and between two CSs, (b) a mechanism that combines CS-CS and CS-US associations and builds 'computational cognitive maps', (c) an attentional rule that 'tunes in' relevant CSs and 'tunes out' irrelevant CSs, (d) performance rules that convert learning variables into topography of the rabbit NM response, and (e) rules that convert learning variables into neuronal firing. The present study explored three hypotheses regarding hippocampal function: (a) hippocampal lesions (HL) impair the 'tuning out' of irrelevant stimuli, (b) hippocampal stimulation (HS) and hippocampal long-term potentiation (LTP) facilitate the 'tuning in' of relevant stimuli, and (c) hippocampal unit activity is proportional to the instantaneous value of associative variables that participate in the 'tuning' mechanisms. Computer simulations for the HL case were carried out for conditioning under different interstimulus intervals (ISI) with different types of US, discrimination reversal, and sensory preconditioning. Computer simulations for the HS and LTP case were carried out for acquisition of delay conditioning and of classical discrimination. In addition, simulations of hippocampal unit activity during acquisition and extinction are presented. Under the 'tuning out' hypothesis for the HL case, the model proved capable of simulating a large portion of the experimental data, showing discrepancies with relevant literature only when describing HL effects on trace conditioning with shock US under short and long ISIs, trace conditioning with air puff US under long ISIs, discrimination reversal and sensory preconditioning. Under the 'tuning in' hypothesis regarding the HS and LTP case, the model proved capable of simulating acquisition of delay conditioning but not acquisition of classical discrimination. Under the assumption that neuronal activity is proportional to the instantaneous value of associative variables, the model is able to simulate hippocampal unit activity.
Animals↗
Repeat balloon aortic valvuloplasty for aortic valve restenosis.
Effective balloon aortic valvuloplasty (BAV) is limited restenosis. After aortic valve restenosis six patients underwent repeat BAV. In spite of the use of larger balloons there was a trend toward a less satisfactory result after repeat BAV (0.98 +/- .26 cm2 vs. 1.2 +/- .26 cm2), which did not reach statistical significance, P = .14. Mortality of the patients at 6 months was 50%. Repeat BAV may be less efficacious than the original procedure.
Aged↗