Showing papers by "Temple University published in 1982"
TL;DR: The findings highlight the fetal period as the time of greatest expansion of the Sertoli cell population and indicate that, at birth, proliferation of these cells is already on the decline.
Abstract: Proliferation of Sertoli cells during fetal and postnatal development of the rat was examined and quantified with light microscope autoradiography. Fetuses in utero were injected subcutaneously with 3H-thymidine. The percentages of Sertoli nuclei that had incorporated label were determined in autoradiographs from fetuses aged 16 through 21 days of gestation. To compare the degree of Sertoli cell proliferation during fetal development with that occurring after birth, pups were also studied at intervals between the day of birth and 3 weeks of age. For each fetus or pup, at least 500 Sertoli cell nuclei in each of three sections were scored as labeled or unlabeled. These data were subjected to analysis of variance and the Newman-Keuls test. The percentage of Sertoli cells incorporating 3H-thymidine increased progressively from day 16 of gestation onward, to a maximum of 26.8% on day 20, two days before birth. Thereafter, this percentage dropped steadily until, in pups 21 days after birth, no labeled Sertoli cells were detected. These findings highlight the fetal period as the time of greatest expansion of the Sertoli cell population and indicate that, at birth, proliferation of these cells is already on the decline.
532 citations
435 citations
TL;DR: A description and explanation of an unexpected echographic appearance in a patient who had sustained an abdominal shotgun wound, simulating a comet tail, is presented and is shown to be a type of reverberation artifact.
Abstract: A description and explanation of an unexpected echographic appearance in a patient who had sustained an abdominal shotgun wound is presented. In the B-scans, a trail of dense continuous echoes, simulating a comet tail, is seen distal to each lead pellet. This comet tail appearance is shown to be a type of reverberation artifact. The effect of object size, shape, composition, and orientation on the appearance of this artifact is demonstrated.
212 citations
TL;DR: Two fundamentally different ways of conceptualizing and measuring firm diversity are identified, their strengths and weaknesses discussed, and their suitability for investigating commonly asked questions evaluated as mentioned in this paper, and a strategic measure of diversity is recommended.
Abstract: Two fundamentally different ways of conceptualizing and measuring firm diversity—by business count and by strategy—are identified, their strengths and weaknesses discussed, and their suitability for investigating commonly asked questions evaluated. A business count measure is claimed to be suitable for research comparing diversified and nondiversified firms but not for investigating differences among diversified firms. For the latter task, a strategic measure of diversity is recommended.
201 citations
TL;DR: Present data suggests that combined liquid-solid, dual radionuclide studies afford the greatest information regarding simultaneous gastric emptying patterns of liquid and solid components of a meal, and that single radion Euclide, solid tests of gastic emptying are the more sensitive technique for determining subtle abnormalities of gastrics emptying.
179 citations
TL;DR: Patients and a review of the literature make a strong argument for at least some cases of the DiGeorge anomalad arising from a deletion of the pericentromeric region of chromosome 22.
174 citations
TL;DR: S-Adenosylmethionine was found to methylate DNA non-enzymatically to produce the same putative promutagenic and procarcinogenic lesions formed by carcinogenic chemical methylating agents, and may indicate the mechanism whereby methylated guanine is formed in the liver DNA of rats with chemically induced liver damage.
Abstract: S-Adenosylmethionine was found to methylate DNA non-enzymatically to produce the same putative promutagenic and procarcinogenic lesions formed by carcinogenic chemical methylating agents. The formation of 7-methylguanine was confirmed by u.v. spectrophotometry, the formation of O6-methylguanine and 3-methyladenine was suggested by the cochromatography of radioactivity with standard bases. It is possible that this reaction may explain the presence of constitutive cellular enzymes specifically for the repair of methylated DNA, and may indicate the mechanism whereby methylated guanine is formed in the liver DNA of rats with chemically induced liver damage.
172 citations
TL;DR: The effects of cardiopulmonary bypass with bubble and membrane oxygenator systems on platelet function were studied in 26 patients who had elective coronary arterial bypass grafts and bleeding times increased postoperatively.
169 citations
TL;DR: In this paper, it was shown that simple modules and projective modules over a graded Artin algebra are gradable, and that direct summands of finitely generated gradable modules are also gradable.
164 citations
TL;DR: The results suggest that the majority of psychoactive drugs can be investigated by use of the drug discrimination technique, and that state-dependent learning effects will not accompany clinical use of most psychoactive drug unless intoxicating doses are used.
Abstract: This paper reports preclinical data that may predict the amount of state-dependent learning likely to be produced in humans by various psychoactive drugs. In a T-maze, rats were required to turn right when drugged and left when not drugged to escape from electric shock. The number of training sessions required to learn this drug versus no drug discrimination was used as an indicator of the degree of discriminability of the training drug. Using this procedure, the discriminability of more than 100 common psychoactive drugs was determined at one or more doses. Sessions to criterion usually decreased as dosage was increased. Maximum discriminability occurred at the highest usable dose in most cases, and differed considerably for drugs of various types. The results suggest that the majority of psychoactive drugs can be investigated by use of the drug discrimination technique, and that state-dependent learning effects will not accompany clinical use of most psychoactive drugs unless intoxicating doses are used.
163 citations
TL;DR: Gallbladder emptying may be abnormal in patients with gallstones and the explanation for this abnormality and its relationship to the development of gallstones has not been determined.
Abstract: In this study, gallbladder and gastric emptying were compared in 15 normal subjects and 15 patients with gallstones. A noninvasive technique which uses two gamma-emitting radiopharmaceutical agents to image the gallbladder and stomach simultaneously was employed. Technetium-99m-HIDA was used as a gamma-emitting marker for the gallbladder and indium-111-DTPA was mixed with a standard liquid meal in order to stimulate gallbladder emptying and to measure gastric emptying. In patients with gallstones, gallbladder emptying was diminished significantly compared to normal subjects. In contrast, emptying of the stomach was normal. The gallbladder emptying responses to octapeptide of cholecystokinin, administered either as bolus or infusion doses, were similar in normal subjects and patients with gallstones. These studies suggest that gallbladder emptying may be abnormal in patients with gallstones. The explanation for this abnormality and its relationship to the development of gallstones has not been determined.
TL;DR: The nucleotide sequence of the chick a-actin gene reveals that the gene is comprised of 7 exons separated by six very short intervening sequences (IVS), which makes the actin gene family unique among the eucaryotic genes analyzed to date.
Abstract: The nucleotide sequence of the chick a-actin gene reveals that the gene is comprised of 7 exons separated by six very short intervening sequences (IVS). The first IVS interrupts the 73 nucleotide 5' untranslated segment between nucleotides 61 and 62. The remaining IVS interrupt the translated region at codons 41/42, 150, 204, 267, and 327/328. The 272 nucleotide 3' untranslated segment is not interrupted by IVS. The amino acid sequence derived from the nucleotide sequence is identical to the published sequence for chick a-actin except for the presence of a met-cys dipeptide at the amino-terminus. The IVS positions in the chick a-actin gene are identical to those of the rat a-actin gene. While there is partial coincidence of the IVS in the a-actin genes with the vertebrate b-actin genes and 2 sea urchin actin genes, there is no coincidence with actin genes from any other source except soybean where one IVS position is shared. This discordance in IVS positions makes the actin gene family unique among the eucaryotic genes analyzed to date.
TL;DR: The findings were interpreted as showing that children's spatial representations may rely more than adults' on functional distance and/or that children may have more difficulty than adults keeping many objects in mind simultaneously (integrative processing capacity).
TL;DR: Twelve methods for analysing FCM‐histograms were compared using the same set of data and DNA histograms were measured for L‐929 cells at various times after mitotic selection.
Abstract: . Twelve methods for analysing FCM-histograms were compared using the same set of data. Some of the histograms that were analysed were simulated by computer and some were taken from experiments. Simulated data were generated assuming asynchronously growing cell populations and (i) measurement coefficients of variation (CV) from 2 to 16%; (ii) constant measurement CV or CV's increasing from G1 to G2 phase, and (iii) varying fractions of cells in each phase. Simulated data were also generated assuming synchronous cell populations in which a block in early S phase was applied and released. DNA histograms were measured for L-929 cells at various times after mitotic selection. Labelling indices were also measured for these cells at the same time.
The fractions of cells in the G1, S, and (G2+ M) phases were calculated by each analytical method and compared with the actual fractions used for simulation, or in case of experimental data, with autoradiographic results. Generally, all methods yielded reasonably accurate fractions of cells in each phase with relative errors in the range of 10–20%. However, most methods tended to overestimate G1 fractions and underestimate S fractions. In addition, variations in the shape of the S phase distribution often caused considerable errors. Phase fractions were also calculated for histograms of kinetically perturbed populations, simulated as well as experimental The errors were only slightly larger than for histograms from asynchronously growing cell populations.
TL;DR: The transfection procedure described in this paper is simple and reproducible and, although less efficient than microinjection, ought to be useful in phenotypic and genotypic studies in which transfer of genes to a large number of cells is desirable.
Abstract: We have developed a procedure that gives a very high efficiency of transfection in mammalian cells with low-molecular-weight DNA (approximately 10(4) base pairs). The procedure uses cells in suspension that are shocked with polyethylene glycol 4 h after replating. We compared this transfection technique to the standard technique involving manual microinjection of DNA into the nuclei of mammalian cells, using recombinant plasmids containing the simian virus 40 A gene or the herpes simplex virus thymidine kinase gene or both. The efficiency of transfection depends on a number of variables, the most important of which is the difference in transfectability of different cell lines. In our laboratory, the cell line that had the highest efficiency of transfection was tk-ts13, which is derived from baby hamster kidney cells that are deficient in thymidine kinase and temperature sensitive for growth. Under the appropriate conditions, as many as 70% of these cells can be transfected so that transient gene expression can be detected. With the manual microinjection technique, gene expression is independent of the cell line used and occurs faster than after transfection. The results suggest that the critical stage in transfection is the delivery of DNA molecules to the nucleus. Our experiments also indicate that an enzymatic function, in our case, thymidine kinase activity, gives a higher percentage of positive transfectants than when proteins are visualized only by indirect immunofluorescence. The transfection procedure described in this paper is simple and reproducible and, although less efficient than microinjection, ought to be useful in phenotypic and genotypic studies in which transfer of genes to a large number of cells is desirable.
TL;DR: The Middle Childhood Temperament Questionnaire is a 99-item parent questionnaire for assessing the New York Longitudinal Study temperament traits in 8− to 12-year-old children.
Abstract: The Middle Childhood Temperament Questionnaire is a 99-item parent questionnaire for assessing the New York Longitudinal Study temperament traits in 8- to 12-year-old children. The nine characteristics measured are the same except that biological rhythmicity has been replaced by predictability. The scale was standardized on 506 children in a pediatric and a school district. Internal consistency and retest reliability are satisfactory, respectively 0.81 and 0.88 for median category values. Together with the Infant Temperament Questionnaire, the Toddler Temperament Scale, and the Behavioral Style Questionnaire this completes a series of scales for gathering more objective and organized temperament data for 4 months to 12 years.
TL;DR: It is confirmed that narcotics in high enough doses may depress the cerebral blood flow (CBF) and the cerebral metabolic rate for oxygen (CMRo2) in rats.
Abstract: There is considerable controversy with respect to the effects of narcotics on the cerebral blood flow (CBF) and the cerebral metabolic rate for oxygen (CMRo2). The present study examined the effects of high doses of intravenous fentanyl (25-400 micrograms/kg) on the CBF and CMRo2 in rats. Cerebral cortical blood flow and metabolism were measured using the 133Xenon modification of the Kety-Schmidt technique. Fentanyl produced a dose-related decrease in both the CBF and the CMRo2. CBF and CMRo2 were maximally depressed by 50 and 35%, respectively, in rats given fentanyl 100 micrograms/kg compared with nitrous oxide-oxygen ventilated controls. The values for CBF and CMRo2 were 168 +/- 15 ml . 100 g-1 . min-1 and 10.3 +/- 0.7 ml . 100 g-1 . min-1, respectively in the nitrous oxide controls compared with 85 +/- 3 ml . 100 g-1 . min-1 and 7.1 +/- 0.1 ml . 100 g-1 . min-1 in animals receiving fentanyl 100 micrograms/kg. Higher doses of fentanyl did not further decrease either CBF or CMRo2 (108 +/- 12 ml . 100 g-1 . min-1 and 7.0 +/- 0.4 ml . 100 g-1 . min-1, respectively for fentanyl 400 micrograms/kg); however, seizures activity was noticed in about 25% of the rats receiving either 200 or 400 micrograms/kg fentanyl. The seizures seemed to be related to the narcotic in that they could be abolished by injections of naloxone. The seizure activity appeared to increase the CMRo2 relative to animals who received the same dose of fentanyl but did not have seizures. The CBF was not affected. The results confirm that narcotics in high enough doses may depress the CBF and CMRo2.
Journal Article•
TL;DR: Repeated daily ECS for 9 days as well as chronic morphine pellet implantation resulted in a significant increase in the number of 3H-DADLE binding sites, which may link pharmacological cross-sensitization (repeated ECS and chronic morphine treatment) with a functional increase inThe number of available opioid receptors.
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TL;DR: For large n it is shown that f(Z) approaches that function which on each face of a "hexagonal mesh" has the value of the centroid of that face.
Abstract: We wish to \int_{S}|Z-f(Z)|^{2},S the unit square, over all choices of f(Z) which take just n values. For large n it is shown that f(Z) approaches that function which on each face of a "hexagonal mesh" has the value of the centroid of that face. This problem in the design of quantizers for a pulse-code modulation (PCM) system arose in which pairs of adjacent samples are quantized in an effort to capitalize on the correlation between samples and on the geometry of the plane.
TL;DR: In this paper, a generalization of the classical economic order quantity model is considered, where the traditional parameters of unit cost, selling price, demand rate and set-up cost are constant but the holding cost per unit is a non-linear function of the length of time the item is held in stock.
TL;DR: Increasing the palatability of food has two opposite effects: it promotes overeating and provokes caloric output (energy expenditure). The increase in energy expenditure is too small to compensate for overeating.
Abstract: Increasing the palatability of food has two opposite effects: it promotes overeating and provokes caloric output (energy expenditure). The increase in energy expenditure is too small to compensate ...
TL;DR: Until a safe rate of administration is established, it is recommended that dextrose infusions immediately before delivery be limited to no more than 6 g/h.
TL;DR: Estimation of phase variance proved to be an effective procedure for selection of the optimal frequency band for automatic peak detection and a lower limit for the number of averaged responses required for accurate determination of BAEP wave shape.
TL;DR: The findings indicate modifications of both early and late electrocortical events with selective attention, and that changes can be of several kinds, support the view that attention proceeds in more than one stage.
Abstract: Somatosensory evoked potential (SEP) changes associated with selective attention were investigated. In 16 subjects, SEPs were recorded from five locations while they counted electrical stimuli to one of four randomly stimulated fingers. Sequential SEP events measured included peaks P30 (positivity at 30 msec). P45, N60, P100. N140. P190. N230, P400. Counting was associated with greater P45, P100. P190, N230, and P400 amplitudes; effects were not attributable to eye or tongue activity. Analyses designed to reveal changes associated with two conceptualized “channels” (finger class, hand) showed that the P45, P100, and P190 amplitude increases involved both channels. The P400 effect was limited to the target finger. Channel effects for N60 and N140 amplitudes resulted from decreases localized to the unattended element of one channel, suggesting “inhibition.” Latency effects involved mainly the hand channel; counted hand latencies were shorter for P30, P45, P100 and P190. The findings indicate modifications of both early and late electrocortical events with selective attention, and that changes can be of several kinds. They support the view that attention proceeds in more than one stage.
TL;DR: A 2.8-fold decrease in free Mn(I1) with no change in the total cell Mn(II) in response to fasting is demonstrated.
TL;DR: In this article, the authors describe a nematic liquid crystalline phase of negative diamagnetic anisotropy which readily orients in a magnetic field, and the phase transition temper...
Abstract: Disodium cromoglycate in water (~10-15% by weight) forms a nematic liquid crystalline phase of negative diamagnetic anisotropy which readily orients in a magnetic field. The phase transition temper...
TL;DR: Average daily dose per month and its variability from year to year is shown for each station and no consistent long term change in solar UV‐B radiation reaching the ground is evident.
Abstract: — Data are presented from 14 sites where continuous measurements of the sun's shortest ultraviolet radiation reaching the earth's surface have been made for four or more years. Average daily dose per month and its variability from year to year is shown for each station. Some of the many influences affecting these measurements can be discerned by station intercomparisons. No consistent long term change in solar UV-B radiation reaching the ground is evident.