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At least 451 records · Page 25Linked to original sources
PubMed1975

Clomiphene citrate in suppression of puerperal lactation.

Demand for inhibiting puerperal lactation has brought about a plethora of methods, none entirely satisfactory, in achieving successful and comfortable ablactation. In addition some were associated with untoward side effects. In this study administration of 100 mg. of clomiphene citrate daily for 5 days was effective in suppressing puerperal lactation. Response to the treatment was particularly pronounced, when this was started within the first 12 hours post partum.

Clomiphene↗
PubMed1977

Monozygosity in twins: a detailed investigation.

The twins presented in this article showed similarities in their physical make-up to a very high degree. Statistically, however, it is the blood picture which holds the "trump card" in this plethora of evidence supporting monozygous twinning, and it is an essential prerequisite in any presentation of this nature. It is perhaps noteworthy that, while only one of the twins sucked his thumb habitually, there was no difference in the degree of postnormality of the posterior teeth but merely a change in the interincisor relation and in the palatal height. It can clearly be seen from the study of these two twins that the differences between them were very small indeed and could quite easily be classed as individual variations within the same identical genetic pattern. Similarly, in any other identical twins, the way in which one differs from another must be to a similarly small degree or the cause of the difference must clearly be attributable to environmental or acquired influences. Differences which cannot be classed as other than genetic show us that the twins are fraternal or dizygous and, therefore, no more alike than would be two brothers of differing ages.

Blood Chemical Analysis↗
PubMed1983

On the use of nomograms to determine the elastic property ratios of orthodontic arch wires.

With an 0.012 inch stainless steel arch wire as the base line, a series of calculating charts which express the strength, stiffness, and range ratios of orthodontic arch wires is introduced. In each case, both the bending and the torsional stress states are computed over a broad range of wire sizes. Three distinct situations are addressed: the over-all spectrum of elastic property ratios among stainless steel, nickel-titanium, and beta titanium wires; the intra- and interproperty relationships of these wire compositions; and the role which elastic property ratios play in the selection of the right arch wire. Via these nomograms, clinicians will have another means available by which the plethora of wire compositions and cross sections may be assessed.

Dental Alloys↗
PubMed1993

The role of video-assisted thoracic surgery for carcinoma of the lung: wedge resection to lobectomy by simultaneous individual stapling.

Despite a plethora of technologic advances, there has been only minimal improvement in the surgical treatment of carcinoma of the lung during the past 15 years. The advent of video-assisted thoracic surgical (VATS) techniques, however, is opening up new vistas and providing unimagined options for more accurate diagnosis, more precise staging, and more specific resections of lung tumors. Currently, a voluminous surgical literature supports tissue conservation, in selected patients, for the curative resection of peripheral malignant nodules less than 2 cm in diameter. Because these lesions are very accessible to a VATS resection, such procedures can be satisfactorily performed to meet the individual needs of the patient (ie, wedge, subsegmental, segmental, and sublobar resections, as well as traditional or SIS-lobectomy [simultaneous individual stapling of hilar structures]). As the technology advances, members of other specialties are beginning to develop a keen interest in the treatment of carcinoma of the lung. If thoracic surgeons are to prevail in the treatment of carcinoma of the lung, for the benefit of their patients, they must remain vigilant, informed, and versatile in their approach to this disease. This involves learning, understanding, and incorporating these new technologic advances into their armamentarium.

Humans↗
PubMed1994

Kinetics of ligand binding of cytochrome oxidases: a comparative study.

The plethora of microbial oxidases revealed by photochemical action spectra (Chance, B. (1989)) Biochim. Biophys. Acta 1000, 345-347) has led to detailed identification, purification and overproduction in many species, to the point where kinetic comparison of properties seems to allow structure/function deductions. This work compares the carbon monoxide recombination of five types of oxidases obtained from various organisms. The results are plotted in an Arrhenius-type plot and suggest that the carbon monoxide ligation is a sensitive indicator of the heme environment specific for an oxidase expressed under a given oxygen concentration. This survey of the carbon monoxide recombination kinetics of naturally occurring cytochrome oxidases in whole cells shows evidence for structural control of the reaction kinetics.

Animals↗
PubMed1995

MPTP- and MPP(+)-induced effects on body temperature exhibit age- and strain-dependence in mice.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is toxic toward the dopaminergic nigrostriatal system of a plethora of species including rodents, nonhuman primates and humans. The present study was designed to evaluate if systemic administration of MPTP or its metabolite, 1-methyl-4-phenylpyridinium ion (MPP+), has significant effects on body temperature (BT) and whether such effects might play a role in the neurotoxicity. A single intraperitoneal (i.p.) dose of either MPTP (50 mg/kg) or MPP+ (12.5 mg/kg) leads to a decrease in BT in both C57BL/6N (C57) and CD-1 mice. The hypothermia induced by MPTP can be blocked by pretreatment with deprenyl (30 mg/kg, i.p.), an MAO-B inhibitor. However, the hypothermia elicited by MPP+ is refractive to MAO-B inhibition. These findings suggest that MPP+ is responsible for the BT reduction and that the primary site of action lies outside the blood-brain barrier. An initial hyperthermic phase in the CD-1 mice, which leads to the induction of heat shock protein-72 (HSP-72) throughout the brain, differentiates their response to MPTP from that of C57 mice. This initial hyperthermia appears to be protective since its prevention by dosing at a low ambient temperature enhances striatal dopamine (DA) depletion in CD-1 mice. The temperature effects of both MPTP and MPP+ also display an age-dependence in the C57 strain of mice, with the magnitude of the effects correlating positively with age. However, profound hypothermia could be induced by MPP+ in the absence of striatal DA depletion. The latter finding suggests that while a positive correlation was found between age and the magnitude of the hypothermia, DA depletion and hypothermia are not causally related. The apparent protective effect of the initial hyperthermia in the CD-1 strain of mice, however, suggests that BT is an important parameter in the neurotoxicity of MPTP.

1-Methyl-4-phenylpyridinium↗
PubMed1983

The vascular features of plexiform neurofibroma with some observations on the importance of pre-operative angiography and the value of pre-operative intra-arterial embolisation.

The presence of abnormal feeding vessels in plexiform neurofibromata of the head and neck has been demonstrated by angiography in three patients. Attention is drawn to the possibility of dangerous bleeding in the treatment of these lesions. Two other patients presented with a similar lesion over the trunk: in one patient there was excessive bleeding during surgical excision but not in the other, despite their very similar clinical appearances. It is suggested that two varieties of plexiform neurofibromata exist which are distinguishable only by angiography: those with a normal vasculature and those with a plethora of abnormal vessels forming an integral part of the lesion along with the neural and fibrous elements (haemangioneurofibroma). A method of treatment is proposed based on pre-operative embolisation followed by complete surgical excision. The futility of pre-operative vessel ligation is confirmed.

Adult↗
PubMedDate not supplied

Experience of 73 free groin flaps.

The free groin flap has gradually lost its popularity due to the disadvantages relating to the pedicle and the plethora of new donor sites. The purpose of this article is to re-evaluate this time-honoured free flap and to demonstrate its reliability and versatility through a review of 73 free groin flaps performed between 1985 and 1990. 7% of free transfers (total 1096 cases) in our institution were free groin flaps. The complication rate was 8% (three complete failures and three partial failures). This result is acceptable and not so high as other reports have described. The artery discrepancy is the main cause of the complication rate. Two special techniques to gain additional diameter of vessel size to overcome the pedicle disadvantages are stressed. The groin flap has proved to be useful and still deserves consideration in reconstructive procedures.

Adolescent↗
PubMed1995

Removal of lactoferrin from plasma is mediated by binding to low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor and transport to endosomes.

LDL receptor related protein (LRP) is a ubiquitously expressed cell surface receptor that binds, at least in vitro, a plethora of ligands among them alpha 2-macroglobulin and lactoferrin (Lf). The function of LRP in internalisation and distribution of ligands within cellular metabolism is still unclear. We here investigated by combined ligand- and immunoblotting the participation of LRP/alpha 2MR and its associated protein (RAP) in receptor mediated endocytosis of Lf into rat liver. We found LRP highly enriched in sucrose density gradient fractions around density 1.10 g/ml, previously characterised as endosomal fractions. RAP was concentrated in distinct fractions around density 1.14 g/ml. This separation of RAP from LRP/alpha 2MR is physiologically meaningful as RAP avidly binds to LRP/alpha 2MR and by that shuts off all ligand binding function. In endosomal fractions we found one single binding protein for 125I-labelled Lf. With a specific anti LRP/alpha 2MR antibody and ligand blotting with 125I-labelled RAP this endosomal Lf binding site was verified to be LRP/alpha 2MR. Endosomes did not bind labelled Lf when prepared from rats that received an intravenous injection of Lf (20 mg per animal) 20 min prior to preparation. Surprisingly we immunodetected Lf in these endosomes at a position around 600 kDa, comigrating with LRP/alpha 2MR. We determined Lf binding to be optimal at pH 5.8, what led us to suggest the existence of a very stable LF-LRP/alpha 2MR complex in endosomes. These data support the idea of effective binding of Lf at pH as found in inflamed tissue environment where Lf is reported to be involved in leukocyte mediated inflammation regulation.

Animals↗
PubMed1995

Mitochondrial DNA rearrangements: intracellular information system.

The extent of mtDNA rearrangements has been analyzed in nDNA preparations of rat and human with a statistically representative group of oligonucleotides directed to two regions of mtDNA: genes for cytochrome oxidase subunits I and III. Human PCR preparations generated with oligonucleotides directed 'normally' showed the expected fragment for mtDNA and the presence of a plethora of fragments with rearrangements (deletions and insertions), in contrast to rat PCR preparations under the same reaction conditions in which these kinds of rearranged fragments were rarely observed. Both human and rat PCR preparations generated with oligonucleotides directed 'inversely' showed numerous fragments, some of which showed differences in copy number correlating with distinct phases during development/aging. Sequence analysis of some normal and rearranged fragments demonstrated in all cases DNA sequences 99% homologous with other mtDNA sequences at rearranged fragments. No evidence of nuclear DNA sequences was found. The following scheme is proposed for mtDNA rearrangements during the lifetime of an organism: variation in copy number of some fragments with inversions of mtDNA depends on the specific developmental/aging period; in old cells there is an increase in higher molecular weight mtDNA deletions. These findings strongly suggest that the mtDNA rearrangements play a role as an intracellular 'information system'.

Adult↗
PubMed1995

Staining methods in gel electrophoresis, including the use of multiple detection methods.

Polyacrylamide gel electrophoresis is a reliable and widely used technique for the separation, identification and characterization of proteins and protein mixtures. With the introduction of high resolution two-dimensional polyacrylamide gel electrophoresis in 1975 upward to 2000 individual polypeptides spots are easily separated on a single electrophoretic gel thereby necessitating the availability of highly sensitive protein detection methods. Although a plethora of protein-staining and -visualization protocols have been described utilizing both radioactive and non-radioactive reagents, many times the use of mono-dimensional detection procedures is insufficient to address the experimental questions asked. The present review highlights the utilization of combined protein-labeling and -staining methodologies in gel electrophoresis including selected applications in polyacrylamide gels and solid membrane matrixes.

Electrophoresis, Polyacrylamide Gel↗
PubMed1989

Endothelium as a transducing surface.

Endothelial cells responses to a variety of agonists include release of endothelium dependent vasodilators, such as endothelium dependent relaxing factor (EDRF) and prostacyclin (PGI2). These substances act on vascular smooth muscle to cause relaxation and also have potent anti-aggregatory effects on platelets. A study of the mechanisms of signal transduction involved in these processes was undertaken. An investigation of intracellular calcium using FURA-2 and INDO-1 loaded endothelial cells shows transient elevation in response to vasodilator agonists. The calcium content of endothelial cells calculated using 45Ca flux techniques is increased in response to bradykinin and thrombin. Receptor activation leads to increased phosphoinositide turnover in endothelial cells and activates protein kinase C, the latter may be involved in feedback regulation. Patch clamp studies have demonstrated receptor-operated ionic channels in the endothelial cell membrane. Thus, intracellular calcium concentration is elevated in response to receptor activation, both as a result of liberation of calcium from intracellular stores and calcium entry from extracellular sources. Endothelial cells also respond to particulate stimuli. They can selectively bind and phagocytize bacteria. Phagocytosis leads to generation of superoxide aionin, a process which also seems to be controlled by elevation of intracellular calcium and activation of protein kinase C. In addition phagocytosis activates endothelial cells resulting in increased migration, division and further phagocytosis. All in all, the plethora of different endothelial responses to a variety of stimuli suggests a complex and multipotent cell type.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Endogenous natriuretic factors 1: sodium pump inhibition does not correlate with natriuretic or pressor activities from uremic urine.

It is our purpose to isolate and characterize the putative "Natriuretic Hormone", ostensibly responsible for ECF homeostasis, as well as identify endogenous pressors and compounds that induce prolonged natriuresis; we report here our initial progress in this area. Large volumes of pooled urine collected from uremic patients were fractionated, and the resulting isolates were evaluated for in vivo natriuretic and pressor effects and Na+/K(+)-ATPase inhibitory activity in renal cells. The purification steps involved ultrafiltration to obtain materials of less than 3000 da, gel filtration, and sequential reversed-phase high performance liquid chromatography (HPLC). After each HPLC step, the fractions were evaluated for their ability to elicit significant natriuresis and/or influence mean arterial pressure in the normal conscious female rat. Each fraction was also assayed for its ability to inhibit Na+/K(+)-ATPase as determined by the inhibition of 86Rb+ uptake into MDBK renal cells. While several of the fractions elicited profound natriuresis and/or pressor activity and other fractions inhibited Na+/K(+)-ATPase, there was no correlation among the activities in individual fractions. We have concluded that this plethora of bioactivities is responsible for much of the confusion and multiplicity of crude isolates claimed to be the putative hormone. Presently we are attempting to purify each of these activities to chemical homogeneity for structure determination.

Animals↗
PubMed1990

Measures of hospital market structure: a review of the alternatives and a proposed approach.

Efforts to evaluate the plethora of recent programs adopted by public and private payers to promote hospital price competition critically depend on the availability of measures of local market structure. To gauge the effects of these policies, researchers must be able to delineate hospital market areas and measure the intensity of competition within these markets. This article reviews alternative methods that have been used to define hospital market areas and measure market structure. We propose an empirical patient origin-based method for measuring hospital market structure. The results of sensitivity analyses using data on California hospitals demonstrate the robustness of our measures over a broad range of parameter values.

California↗
PubMedDate not supplied

Recent advances in the cell biology of aging.

Cultured normal human and animal cells are predestined to undergo irreversible functional decrements that mimic age changes in the whole organism. When normal human embryonic fibroblasts are cultured in vitro, 50 +/- 10 population doublings occur. This maximum potential is diminished in cells derived from older donors and appears to be inversely proportional to their age. The 50 population doubling limit can account for all cells produced during a lifetime. The limitation on doubling potential of cultured normal cells is also expressed in vivo when serial transplants are made. There may be a direct correlation between the mean maximum life spans of several species and the population doubling potential of their cultured cells. A plethora of functional decrements occurs in cultured normal cells as they approach their maximum division capability. Many of these decrements are similar to those occurring in intact animals as they age. We have concluded that these functional decrements expressed in vitro, rather than cessation of cell division, are the essential contributors to age changes in intact animals. Thus, the study of events leading to functional losses in cultured normal cells may provide useful insights into the biology of aging.

Animals↗
PubMed1981

Delayed traumatic vertebral body compression fracture; part I: clinical features.

We have described three patient who sustained trauma to their spines followed by persisting pain. Initial radiographs were negative, but on subsequent examinations compression fractures were demonstrated. This sequence of events resembles the clinical picture described by Kümmell in 1895 with significant differences. A plethora of early written description with minimal radiographic documentation suggests that this is a relatively rare condition. It is appropriate, therefore, to present these cases with the suggestion that traumatic injuries with persisting thoracic or upper lumbar back pain should be followed up radiographically in order to demonstrate the occurrence of subsequent compression fractures. These fractures may be treated with simple braces.

Aged↗
PubMed1994

Use of steady state kinetic methods to elucidate the kinetic and chemical mechanisms of retroviral proteases.

Despite the current plethora of structural data of HIV-1 protease and the availability of potent inhibitors, whose structures are based in part on the presumed mechanism of action of this enzyme, our actual understanding of its chemical mechanism has been until now based largely on the precedents of the mammalian and fungal aspartic proteases and static three-dimensional data. The available steady state kinetic data of the protease, as reviewed here, constitute a first step in a detailed description of the mechanism of the enzyme to complement the structural data.

Amino Acid Sequence↗
PubMed1994

The history of trephination in Africa with a discussion of its current status and continuing practice.

Trephination of the skull is one of the most fascinating and, certainly, one of the oldest therapeutic procedures known to man. After Prunières' discovery of the trephined skull at Aiguières in 1868, a plethora of information has been gathered about the procedure. There, however, exits little documentation of African trephination or its history. Using both primary and secondary sources, we have discovered that African trephination was known in the time of Herodotus, has a rich history, and is currently practiced widely throughout Africa for specific reasons. We discuss these findings as they relate to preconceived notions of trephinations in other countries and to the history of neurosurgery.

Africa↗