Translational control during early Dictyostelium development: possible involvement of poly(A) sequences

A rapid decrease in the translational efficiency of mRNA synthesized during vegetative growth is associated with the initiation of development in Dictyostelium discoideum. In contrast, newly synthesized mRNA associates with polysomes with high efficiency. Discrimination between these two mRNA populations correlates with a rapid shortening of the poly(A) tract on the preexisting mRNA. A model is proposed in which a critical poly(A) length regulates the pattern of protein synthesis by affecting the efficiency with which mRNAs can interact with the translational machinery. The model suggests that transcriptional and translational controls can be coupled by altering the state of adenylation of the preexisting mRNA population. The model allows radical changes in the pattern of protein synthesis without wholesale destruction of preexisting mRNA.

Psychological aspects of dentofacial esthetics and orthognathic surgery

The literature and the results of the survey clearly confirm that physical attractiveness plays a major role in the social life and interaction among individuals. Cosmetic improvement is a powerful motivating factor leading people to seek treatment. Those who believe that the rewards of facial improvement will enable them to lead more satisfying and comfortable lives should be encouraged to proceed with the treatment. However, it is absolutely essential that those contemplating treatment be counseled before-hand and fully informed on the prognosis, risks and hazards, advantages and disadvantages of such procedures before embarking on treatment.

Possible involvement of poly(A) in protein synthesis

The experiments of this paper have re-evaluated the possibility that poly(A) is involved in protein synthesis by testing whether purified poly(A) might competitively inhibit in vitro protein synthesis in rabbit reticulocyte extracts. We have found that poly(A) inhibits the rate of translation of many different poly(A)+ mRNAs and that comparable inhibition is not observed with other ribopolymers. Inhibition by poly(A) preferentially affects the translation of adenylated mRNAs and can be overcome by increased mRNA concentrations or by translating mRNPs instead of mRNA. The extent of inhibition is dependent on the size of the competitor poly(A) as well as on the translation activity which a lysate has for poly(A)+ RNA. In light of our results and numerous experiments in the literature, we propose that poly(A) has a function in protein synthesis and that any role in the determination of mRNA stability is indirect.

The role of conservative surgery in the management of inverted papilloma

A group of 31 patients with inverted papilloma were treated at the Mount Sinai Medical Center. There were no multicentric cases, and one patient had an associated malignancy. A conservative procedure consisting of intranasal or transantral sphenoethmoidectomy was selectively performed in 8 patients with limited lesions. No recurrences were observed in this group after a mean follow-up of 2 years. Lateral rhinotomy with medial maxillectomy and en bloc resection of the ethmoid labyrinth was performed in 23 other patients. One recurrence appeared in this group, members of which were followed a mean of 3.8 years. Radiographic evaluation by multidirectional polytomography and CT scanning permits identification of a small group of patients who have limited lesions and may be candidates for conservative tumor excision.

Messenger RNA half-life in Dictyostelium discoideum

Messenger RNA half-life in vegetatively growing cells of Dictyostelium discoideum was determined using a uridine pulse-chase procedure. In these experiments, mRNA decayed in a complex fashion, and consisted of at least two major components, one with a half-life of about 50 min and a second with a half-life of about 10 hr. These results independently confirm our previous studies on the decay of mRNA extracted from actinomycin D-treated cells. Since these results were in apparent conflict with half-life determinations obtained with a combination of actinomycin D and daunomycin (J. P. Margolskee and H. F. Lodish, 1980a, Dev. Biol. 74, 37-49), we have also studied mRNA half-life in cells treated with a combination of both drugs and found that simultaneous use of both drugs leads to accelerated mRNA decay and other noticeable side effects. In light of our observations, we have suggested an alternative to conclusions drawn by others with respect to mRNA synthesis and stability in Dictyostelium development.

The MARS appliance. Report of a case

Inconsistent wearing of functional appliances, intermaxillary Class II elastics, and headgear during the treatment of Class II malocclusions is a common concern of many orthodontists. The MARS (Mandibular Advancing Repositioning Splint) is a functional device designed to overcome many such cooperation deficiencies. The MARS appliance is a fixed functional device which is attached to the arch wires of a multibanded orthodontic appliance. It is composed of a piston and cylinder which attach to the lower canine and the upper molar region of the dental arch wires on each side of the jaw. It forces the patient to maintain the mandible in a protruded position 24 hours a day and yet allows full and complete opening and closing as well as lateral excursive movement. The design, method of attaching, and adjustment of the appliance during treatment are discussed, and the results achieved in a single case are described. The results being achieved in the pilot study so far are encouraging and are being pursued further.

Growth and its relation to orthodontic treatment

Surgery has become an invaluable adjunct to orthodontic therapy. However, before embarking on surgical procedures, particularly in growing individuals, it is necessary to appraise each case carefully to determine whether the dentofacial dysplasias can be corrected by orthodontic or orthopedic means. It is possible by the use of investigative procedures to determine the extent and severity of malocclusions and any associated dentofacial dysplasias. General growth rates, increments, and directions can be predicted with some degree of accuracy. Likewise, favorable and unfavorable growth patterns can usually be identified. However, there are those cases in which, for reasons unknown, the growth patterns do not follow the usual trends. These cases often do not respond satisfactorily to treatment because of bizarre or unanticipated growth patterns. Science, unfortunately, has not progressed sufficiently so that such patterns can be identified ahead of time. Until the secrets of such growth patterns are uncovered, treatment procedures, response to the therapy, and growth predictions, of necessity, must be based on average growth trends.

A carbohydrate-containing form of immunoreactive calcitonin in transplantable rat medullary thyroid carcinomas

Extracts of transplantable rat medullary thyroid carcinomas were fractionated by concanavalin A-agarose chromatography and SDS-polyacrylamide gel electrophoresis. While tumor extracts contained mostly (greater than 90%) native calcitonin, 4 distinct larger calcitonin species (Mr = 27,000, 17,000, 13,700, and 9,600) were also observed. Glycoprotein fractions from lectin-affinity chromatography of the tumor extracts contained 0.3-1.5% of the total immunoreactive calcitonin. Gel electrophoresis of the pooled glycoprotein fractions demonstrated that the predominant forms of immunoreactive calcitonin were larger than calcitonin monomer. One high molecular weight species (Mr = 9,600), isolated in sufficient quantity from the polyacrylamide gels for reapplication to concanavalin A-agarose, was specifically eluted from the lectin, indicating that it was a glycoprotein. These results are the first evidence that intact C-cells contain at lest one high molecular weight glycoprotein form of immunoreactive calcitonin and suggest that addition and removal of carbohydrate side chains occur during processing of calcitonin precursors to the native hormone.

Inhibitory effects of 2,3,5-triiodobenzoic Acid on ion absorption, respiration, and carbon metabolism in excised barley roots

The ability of 2,3,5-triiodobenzoic acid (TIBA) to alter ion absorption, respiration, carbon metabolism, and the permeability of the cell membranes of excised barley roots has been examined. Roots pretreated in either H(2)O, KCl, or TIBA followed by treatment in KCl, TIBA, or KCl and TIBA demonstrated that inhibition of ion uptake due to TIBA was reversible. These studies also suggest that ions already accumulated within the vacuole remain sequestered after the addition of TIBA, whereas cytoplasmic ions leak out into the external medium. A 20-minute lag period was present prior to the onset of inhibition of O(2) consumption by TIBA. A b-type cytochrome from corn that is apparently associated with the plasmalemma and possibly involved in respiration or ion uptake, or both, was unaffected by TIBA. The addition of TIBA to treatment solutions resulted in the synthesis and accumulation of ethanol. Analysis of organic acids showed that only the malate concentration was affected by treatment with TIBA. A reduction of 26% was noted for malate in the presence of 2 micromolar TIBA. These combined results suggest that the inhibitory action of TIBA in barley roots involves an alteration of mitochondrial respiration and not a direct depolarization of the plasmalemma.

Orthognathic diagnosis using the proportionate template

Most traditional cephalometric analyses relate various craniofacial landmarks to anterior cranial base (sella or nasion) or to Frankfort horizontal plane. Such analyses do not accurately reflect the extent of anteroposterior or vertical jaw dysplasias. In addition, traditional cephalometric analyses do not provide adequate information relative to the specific jaw at fault, that is, whether either or both are too protrusive or retropositioned. The Wits appraisal provides reliable information relative to anteroposterior relationship of the jaws to each other. The proportionate template is designed to enable jaw dysplasias to be identified on lateral cephalometric headfilms without having to rely on either anterior cranial base or Frankfort horizontal plane. Various methods of applying the template are outlined, and the advantages and its usefulness in clinical situations are described.

Detrimental effect of endometrial biopsies on pregnancy rate following human menopausal gonadotropin/human chorionic gonadotropin-induced ovulation

The effect of luteal phase endometrial biopsy was studied in 33 anovulatory women treated with human menopausal gonadotropins (hMG) to induce ovulation and pregnancy. Over-all, 33 of 85 ovulatory cycles resulted in pregnancy (39%). Of 50 nonbiopsied cycles, 26 resulted in pregnancy (52%) whereas only 7 of 35 biopsied cycles resulted in pregnancy (20() (P less than 0.01). Four pregnancies terminated in spontaneous first-trimester abortions, 12% in the nonbiopsied group and 14% in the biopsied group. Luteal phase endometrial biopsy significantly lowers pregnancy rates in hMG-induced ovulatory cycles, but does not change abortion rates.

Inhibition of respiration and ion uptake by 2,3,5-triiodobenzoic Acid in excised barley roots

The addition of 1 micromolar 2,3,5-triiodobenzoic acid (TIBA) to solutions containing KCl resulted in the inhibition of K and Cl uptake in excised barley roots. The effectiveness of TIBA as an inhibitor increased as the pH of the treatment solution decreased and approached the pK(a) of TIBA. A lag period of approximately 20 minutes existed prior to the onset of TIBA induced inhibition of ion uptake. Respiratory activity was also inhibited by TIBA. The data suggest that in this material, TIBA functions by entering the cytoplasm and inhibiting metabolism. Comparisons made on the effect of added Ca, showed that at pH 5.7 and higher, Ca had no effect on ion uptake whereas at lower pH values the presence of Ca enhanced uptake by offsetting the deleterious effects of H(+).

Diagnosis of mental disorder in adults and increased use of health services in four outpatient settings

The differential use of medical services by patients with and those without a diagnosis of mental disorder was examined in four adult populations by age, sex, diagnosis, and medical department used. The four settings offered comprehensive services to patients who varied greatly in socioeconomic status. In all four settings patients with a diagnosis of mental disorder used all services and general health services more than patients without such a diagnosis. Results document increased medical morbidity and a greater likelihood of a diagnosis of an ill-defined condition in patients with mental disorder than that found in patients without a diagnosis of mental disorder.

Point A revisited

Point A cannot be accurately identified in all cephalometric radiographs. In instances where this landmark is not clearly discernible, an alternative means of estimating the anterior extremity of the maxillary base is shown. A point plotted 3.0 mm. labial to a point between the upper third and lower two thirds of the long axis of the root of the maxillary central incisor was found to be a suitable point (estimated point A) through which to draw the NAE line and one which most closely approximates the true NA plane.

A key to the understanding of extraoral forces

By following certain basic principles, the effects, advantages, and disadvantages of the wide assortment of extraoral assemblies marketed are easily understood. The key to this understanding is the appreciation of the relationship of the line of action of the force application to the center of resistance of the tooth. These principles are discussed in three planes of space: sagittal, coronal, and transverse. Because of the many variables and complexity of mathematically computing the force effects of unilateral or asymmetric extraoral assemblies on molar teeth, a mechanical testing apparatus was designed to accommodate the various face-bows. Not all the designs proved effective, and many of the clinical side effects of the respective face-bow designs became manifest on mechanical testing.

The proportionate template as a diagnostic aid

Many traditional cephalometric analyses used do not consistently reflect the extent of anteroposterior or vertical jaw dysplasias. Nor do such analyses give accurate information as to which jaw(s) is at fault. The proportionate template is designed as a diagnostic aid which enables the clinician to identify and determine rapidly the extent of craniofacial skeletal jaw discrepancies in adults. The template is found to be particularly useful for orthodontists and surgeons engaged in orthognathic surgery. (Proportionate templates are available upon request from the author).

The maxillary orthopedic splint

Craniomaxillary orthopedic correction of the skeletal imbalance of Class II malocclusions is often the desired method of treatment in these cases. The ability to apply a "pure" orthopedic force to the maxillary complex has so far eluded research efforts. However, the use of a maxillary splint with a high-pull extraoral traction assembly has been shown to be most effective in reducing Class II skeletal dysplasias through a combination of dentoalveolar and basal bone changes. Force delivery to the maxillary complex in Class II skeletal jaw disharmonies is through the teeth. The philosophy behind the use of the maxillary splint is that if the force delivered to the upper jaw involved the use of all the upper teeth (and hard palate) rather than only the maxillary first molars, as in conventional extraoral orthodontic therapy, the effect on the jaws would be more orthopedic than orthodontic in nature. The advantages of the use of the maxillary splint in the younger patient with a severe Class II malocclusion are that it reduces the vulnerability of the maxillary incisors to accidental fracture, while concomitantly reducing the Class II dysplasia, thereby effectively shortening the later-stage multiband corrective time and procedures. Further advantages of the maxillary splint described are ease of construction and clinical application, which makes it an attractive appliance for use in dental clinics or institutions in which patient volume, infrequent visits, and ecomomic factors are major considerations. This preliminary report on the philosophy of treatment procedure and description of the appliance design is to be followed by a further cephalometric and clinical evaluation of results achieved with its use.

The craniofacial skeletal pattern of the South African Negro

Lateral cephalometric head film measurements on twenty-seven male and twenty-eight female adult craniums and mandibles with excellent occlusions were compared with similar measurements on Caucasoids with excellent occlusions. Among the differences between the two groups is the forward position of the short maxilla relative to the anterior cranial base in the South African Negro. The forward location of point A has the effect of increasing the ANB angle, since the relative position of point B in both groups is much the same. Unlike the American Negro, the labial inclination of the upper incisors in the South African Negro is not pronounced but is similar to the inclination observed in Caucasoids. Because of the large ANB angle, the lower incisors in the S.A. Negro (as in the American Negro) are severely labially inclined. Ramus height in the S.A. Negro is shorter than that of Caucasoids and appears to be related to the steep mandibular plane observed in the former population group.

Novel properties of bacterial elongation factor Tu

We have characterized novel properties of the bacterial protein synthesis elongation factor Tu which indicate that it may function as a structural protein. Under appropriate conditions, elongation factor Tu polymerizes to form filaments and, more often, bundles of filaments. It is also the predominant component of a complex of proteins from Escherichia coli that undergoes reversible polymerization in the presence of KCl and MgCl2. In addition, purified elongation factor Tu binds tightly to DNase I in the presence of 10 mM MgCl2. In crude extracts the factor shows no binding in the presence or absence of MgCl2. These properties suggest that elongation factor Tu may have certain actin-like properties and that it has cellular functions other than its role in protein synthesis.

The craniofacial pattern of the Lengua Indians of Paraguay

Lateral cephalometric headfilms of 30 male and 30 female Lengua Indians taken in the Chaco area of Paraguay were compared with a sample of 23 male and 25 female South African Caucasoids with excellent occlusion. The most obvious difference noted between the two population groups was the degree of prognathism evident in the Lengua. This was attributed to the generally shorter anterior cranial base in the latter group rather than to the size or forward positioning of their jaws. The significantly larger ANB (Subspinale, Nasion, Supramentale) angle observed in the Lengua was attributed to one or both of two factors, namely, the short anterior cranial base or the clockwise rotation (forward tipping) of the jaws relative to the anterior cranial base. Chinpoint position relative to the anterior cranial base in the Lengua is not much different from that of our Caucasoid sample. The lower incisor teeth in the Lengua, but not the upper ones, are more labially inclined than those of the Caucasoids.

Quantitation of the reticuloendothelial system clearance of soluble fibrin

Phagocytosis of particulate fibrin has been previously established as a function of the reticuloendothelial system (RES). More recently, reticuloendothelial cells have been shown to bind soluble fibrin/fibrinogen (f/F) complexes in vitro. To quantitate RES clearance vs microthrombus formation, varying doses (0.1-6 mg/kg) of 125I-soluble f/F was injected into rabbits. One hour later the animals were killed, at which time 48 +/- 8% of the 125I f/F had been cleared from the blood. Homogenized organ samples were separated into insoluble pellet, soluble protein bound, and free 125I. Treatment of other samples with plasmin prior to homogenization differentiated the insoluble 125I into RES cleared (intracellular-plasmin resistant) vs microthrombi (plasmin sensitive pellet 125I). 125I-f/F was chiefly found in liver and spleen. Injection of low f/F concentrations resulted in no plasmin sensitive pellet 125I. 3 mg/kg f/F caused small, variable amounts of plasmin sensitive pellet 125I, chiefly in the kidney. With 6 mg/kg, 21-50% of the insoluble 125I in all organs was plasmin sensitive, and occasional 1-2 mm thrombi were found. The data indicate complete and rapid RES clearance of small amounts of soluble f/F from the blood, without microthrombi being formed. The RES was acutely saturated at 1.5-3.0 mg f/F/kg, which is equivalent to immediate conversion to fibrin of 1-2% of the intravascular fibrinogen pool.

Tannins as gibberellin antagonists in the synthesis of alpha-amylase and Acid phosphatase by barley seeds

The tannins chebulinic acid or tara tannin were added to an incubation system in which GA(3) induces enzyme synthesis in endosperm half seeds of barley (Hordeum vulgare L.). The activity of amylase and acid phosphatase in the incubation medium was reduced compared to the activity in the medium after incubation with GA(3) alone. When embryo half seeds of barley were incubated with chebulinic acid or tara tannin in the absence of added GA(3), the enzyme activity of the incubation medium was also reduced. The activity of preformed enzymes obtained from endosperm half seeds previously induced with GA(3) was not reduced by the addition of tannin. Comparisons were made of the amount of enzyme activity from breis of aleurone layers incubated with GA(3) in the presence and absence of tannins. The amounts of activity were relatively small and approximately equal in both cases, indicating that secretion from the aleurone was not blocked by the tannins. The reduction of enzyme activity caused by tannins in both endosperm and embryo half seeds could be completely reversed by the addition of GA(3).

Intra-amniotic prostaglandin F2alpha and urea for midtrimester abortion

Intra-amniotic prostaglandin F2alpha, in doses of 2.5 to 20 mg, combined with 80 gm of urea, was an effective, safe, simple, and economical midtrimester abortifacient in 115 patients. The mean abortal time, 15.8 hours, was significantly less than that in prior series in which intra-amniotic hypertonic saline or urea was administered together with constant, intravenous oxytocin infusion. The use of intracervical laminaria tents did not shorten the abortal time. Only eight patients had not aborted within 30 hours; only two had not aborted within 36 hours; and only six received a second intra-amniotic injection. Operative removal of the placenta, when necessary, was accomplished under intravenous sedation in a treatment room. The incidence of infection, nausea, vomiting, and other complications was low.

Estimation of fetal dose to patients undergoing diagnostic X-ray procedures

The estimation of fetal dose incurred by patients undergoing various radiologic procedures can be very perplexing. The problem is especially critical for women who do not know that they are pregnant at the time of x-ray exposure. A desciption is offered of efforts to quantitate the fetal dose by after-the-fact calculations. Such conservatively employed calculations may be essential for a clinical decision regarding therapeutic abortion.

Application of the "Wits" appraisal

The "Wits" appraisal is intended as a diagnostic aid to be used in conjunction with other analyses. Whereas the popularly used ANB angular reading is a simple method of measuring degree of jaw disharmony, there are many instances in which this reading is suspect. The "Wits" appraisal permits easy identification of these shortcomings and substitutes a reasonably reliable means of measuring extent of anteroposterior jaw disharmony.

Simplified control of upper abdominal hemorrhage from the vena cava

Serious upper abdominal hemorrhage can be both frustrating and frightening. Most major vessels in the upper abdomen can be readily dealt with within the abdomen. The upper end of the inferior vena cava is an exception. Control above the liver, below the diaphragm, is difficult and hazardous. The maneuver described here for temporary occlusion within the pericardium is simple and safe. By its use and with control of the lower end at the appropriate level, the main vessel and/or its intrahepatic tributaries then can be approached under direct vision in a relatively bloodless field for safe, accurate ligation and/or reconstruction.

The "Wits" appraisal of jaw disharmony

The "Wits" appraisal of jaw disharmony is a simple method whereby the severity or degree of anteroposterior jaw dysplasia may be measured on a lateral cephalometic head film. The method entails drawing perpendiculars from points A and B on the maxilla and mandible, respectively, onto the occlusal plane. The points of contact of the perpendiculars onto the occlusal plane are labeled AO and BO, respectively. In a sample of twenty-one male and twenty-five female adults selected on the basis of excellence of occlusion, it was found, on the average, that in females points AO and BO coincided and in males point BO was located 1 mm. ahead of point AO. In skeltal Class II jaw dysplasias, point BO would be positioned well behind point AO (positive reading), whereas in Class III skeltal jaw disharmonies, the "Wits" reading would be negative, that is, with point BO ahead of point AO. The advantages of the "Wits" appraisal over that of the conventional ANB angle reading are illustrated and discussed.

Synthesis of messenger RNA and chromosome structure in the cellular slime mold

This paper summarizes our knowledge of the structure and biosynthesis of messenger RNA in the slime mold Dictyostelium discoideum, the arrangement of DNA sequences in the Dictyostelium chromosome, and the changes in the pattern of predominant polypeptides synthesized during Dictyostelium development.

Transcription of polydeoxythymidylate sequences in the genome of the cellular slime mold, Dictyostelium discoideum

Messenger RNA of the cellular slime mold, Dictyostelium discoideum, contains about equimolar amounts of two classes of poly(adenylic acid) [poly(A)]; one is about 25 nucleotides long and the second about 100 nucleotides long. At least half of the messenger RNA molecules contain one sequence each of poly(A)(25) and poly(A)(100); both poly(A) sequences are located near the 3' end of messenger RNA, and the kinetics of their appearance on messenger RNA precursor indicates that poly(A)(25) is added before poly(A)(100). Dictyostelium nuclear DNA contains 14,000-15,000 sequences of poly(dT)(25) which could code for the smaller poly(A) residues. The poly(A)(100) must be added post-transcriptionally. The poly(dT)(25) sequences are interspersed throughout the genome and may well represent transcription termination regions.