Synthesis of Semliki Forest virus RNA requires continuous lipid synthesis

The involvement of lipid biosynthesis in the replication of Semliki Forest virus (SFV) in HeLa cells has been analyzed by the use of cerulenin, an inhibitor of lipid synthesis. The presence of this agent from the beginning of infection blocks the appearance of viral proteins. However, when the antibiotic is added at later stages of infection it has no effect on protein synthesis, the cleavage of viral proteins and their acylation by palmitic acid. Cerulenin is a powerful inhibitor of viral RNA synthesis, as analyzed by [3H]uridine incorporation, incorporation of [32P]phosphate into viral replication complexes, or Northern blot analysis of viral RNAs hybridized with minus- or plus-stranded riboprobes. Finally, analysis of phospholipids made in SFV-infected cells indicates that viral infection clearly stimulates the synthesis of phosphatidyl choline and modifies the membrane formed as analyzed by sucrose gradient centrifugation. Cerulenin blocks the synthesis of phospholipids and inhibits the formation of new membranes. These results show that, when the synthesis of lipids is blocked by cerulenin, SFV RNA replication is hampered, suggesting that the synthesis of viral RNAs needs continuous lipid synthesis and membrane formation.

Production and characterization of human gamma interferon from Escherichia coli

The production of human gamma interferon as intracellular inclusion bodies in Escherichia coli, which simplified the purification process, is described. An expression plasmid carrying lipoprotein and the tryptophane promoters in tandem was used. Preparation of highly pure interferon was achieved using high resolution chromatography after denaturation and renaturation steps. Structural characteristics of this protein were verified by mass spectrometric analysis. Additional control tests have shown the suitability of the final product for clinical purposes.

The role of steroids in reproduction in female elasmobranchs and reptiles

Adequate evidence exists to suggest the importance of temporal changes in steroid hormone ratios in the normal reproductive/vitellogenin cycle in oviparous and viviparous elasmobranchs and reptiles. In oviparous species, where the cycle is relatively short, secretion of gonadal hormones is synchronous; thus inhibitory actions of progesterone (P) on hepatic or reproductive tract functions would be offset by stimulatory actions of estradiol (E), resulting in appropriate vitellogenin secretion and reproductive tract development. In viviparous species, temporal asynchrony of E and P secretion occurs, and the actions of the individual hormones can be more easily dissected out. Thus, during gestation, where P is the dominant hormone, antagonistic or stimulatory actions of E may be prevented, and the inhibitory action of P on vitellogenesis dominant. Hence vitellogenesis is limited to the follicular phase and eggs are retained. Although the elasmobranch and reptilian species discussed here do not form a continuum through phylogenesis, but rather are extant forms of a particular line of evolution, it is possible to extrapolate from these observations to the probable endocrine interactions in a species as viviparity evolves from oviparity. The theoretical intermediate stage would involve; (a) egg retention, (b) extension of the luteal phase and increased P secretion and (c) resulting in E/P asynchrony and potential expression of "independent" P action, egg retention and yolk suppression.

Lipophosphoglycan and secreted acid phosphatase of Leishmania tropica share species-specific epitopes

Several species-specific monoclonal antibodies (T11, T13-T15) which only react with Leishmania tropica, recognize phosphorlated carbohydrate epitopes on lipophosphoglycan and the structurally related molecule, phosphoglycan, which is shed by promastigotes into spent culture medium. During immunoaffinity isolation of [32P]orthophosphate-labeled phosphoglycan on monoclonal antibody T15 conjugated to Sepharose 4B, a high-Mr component (approx. 200,000) was co-purified. The latter material is metabolically labeled with [35S]methionine and [3H]glucosamine. This glycoprotein was separated from phosphoglycan by chromatography on lentil lectin resin. The glycoprotein exhibited a L-tatrate-sensitive acid phosphatase activity, typical of secreted acid phosphatase (EC 3.1.3.2) from Leishmania. Monospecific antibodies to Leishmania donovani-secreted acid phosphatase selectively precipitated the L. tropica enzyme from immunoaffinity purified mixtures of the two antigens, and monoclonal antibodies to lipophosphoglycan precipitate the pure enzyme. Species-specific monoclonal antibodies to L. major lipophosphoglycan also recognized both L. tropica antigens. Treatment of the acid phosphatase with periodate or phosphodiesterase I abolished binding by the monoclonal antibodies to the pure enzyme. These results demonstrate that the two major secreted glycoconjugates of Leishmania tropica, the lipophosphoglycan and the acid phosphatase, share species-specific phosphorylated carbohydrate epitope(s).

Vitellogenesis in reptiles as a model for mammalian sex-differentiated hepatic protein synthesis

The stimulation of yolk protein synthesis by estrogen is a characteristic of female non-mammalian vertebrates; in mammals, or their reptilian ancestors, however, vitellogenesis has been suppressed as a corollary of the evolution of viviparity. It is our hypothesis that progesterone has a dual role in this phylogenetic trend: a) to inhibit myometrial contraction and thus set the stage for internal development of embryos and associated placentation and b) to inhibit yolk protein synthesis in a coordinate manner as placentation became an efficient direct supply of nutrients to the fetus. Despite the absence of vitellogenesis per se in eutherian mammals, significant sex-differentiated hepatic protein-lipid synthetic functions remain, which are under complex hormonal control. We have presented evidence that in the reptiles, the central vertebrate group from which the ancestors of modern mammals evolved, the control of yolk protein synthesis is also complex, involving both pituitary hormones (GH, PRL, and LH) and ovarian steroids (estradiol, testosterone, and progesterone). Adequate evidence exists to suggest that mammalian hepatic lipoprotein synthesis and its regulatory elements are phylogenetically derived from their reptilian ancestors and may be better understood in this context. This is of particular relevance to cardiovascular disease in which there is a clear sex bias yet for which no coordinated research program exists which takes into account the relevant phylogenetic history. We believe that reptilian, and possibly avian, models could be used to great advantage to probe the endocrine components of cardiovascular disease.

The dual role of polyelectrolytes and proteins as mineralization promoters and inhibitors of calcium oxalate monohydrate

Polyelectrolytes and protein molecules appear to be able to act not only as crystallization inhibitors when present in solution, but also as promoters of crystal growth when immobilized onto surfaces. Because this is especially relevant for systems in which heterogeneous nucleation can occur, the influence of poly-L-glutamic (PGlu) acid, poly-L-aspartic (PAsp) acid, and human serum albumin (HSA) on the nucleation and growth inhibition of calcium oxalate monohydrate (COM) was studied using the Constant Composition (CC) kinetics technique. The overgrowth of COM on hydroxyapatite (HAP) seed crystals pretreated with HSA was also investigated. Pronounced differences in inhibiting and nucleating potential were found for the various additives. HSA, a relatively poor growth inhibitor when present in solution, was found to nucleate very regular, hexagonal COM crystals when immobilized on a surface and to enhance the overgrowth of COM when adsorbed on HAP surfaces.

Mineral phases of calcium phosphate

Many studies of calcium phosphate precipitation have been made using relaxation techniques in which the concentrations of the lattice ions are allowed to decrease as equilibrium is approached. Since the nature of the phases that form depend markedly on the solution composition, this decrease can lead to concomitant phase transformations during the crystallization experiments. The results of the present constant composition (CC) studies show that defect apatites may be formed under conditions of sustained supersaturation with a non-stoichiometric coefficient dependent on the pH of the growth medium. An important factor in analyzing these experiments is the initial surface modification and ion-exchange processes involving H+ and Ca2+ ions after inoculation of the supersaturated solutions. Thereafter, active growth sites may be eliminated as the crystals undergo lattice perfection. Transformation of dicalcium phosphate dihydrate to octacalcium phosphate, involving dissolution and subsequent nucleation and growth of the new phase, is also influenced by surface roughening of the initial phase. Typical inhibitors that reduce the rate of growth of seed crystals in supersaturated solutions may actually induce the nucleation of calcium phosphate phases when immobilized on inert surfaces. This may be a factor in the modulation of crystal growth in many biological systems.

Bombesin produces hypothermia in insulin treated rats

Previous studies have shown that central injection of bombesin produces hypothermia in food-deprived, but not food satiated rats at normal ambient temperatures. The present study evaluated the effects of bombesin on core body temperature (Tb) and feeding behavior in rats pretreated with insulin. Administration of bombesin (0.25, 0.5, and 1.0 microgram) into the lateral cerebral ventricle produced hypothermia in rats injected with insulin (10 U/kg; i.m.). No significant change in core temperature was observed in control rats following bombesin. Insulin treatments significantly stimulated feeding behavior and the highest dose of bombesin significantly reduced feeding behavior. The results demonstrate bombesin-induced hypothermia under metabolic conditions similar to acute starvation. These findings are consistent with the hypothesis that bombesin-induced hypothermia in food-deprived rats is directly related to the fasting state.

Influence of family planning counseling in an adolescent clinic on sexual activity and contraceptive use

We evaluated whether family planning counseling (FPC) in an adolescent clinic promoted the onset of sexual activity among the non-sexually active teens and/or increased contraceptive use among the sexually active teens. The FPC focused on the teens' establishing sexual values, the right to say "no," abstinence and alternate forms of intimacy, consequences of intercourse, and the various contraceptive methods. Data for one year were collected on the adolescents' first and subsequent visits to a medically oriented, municipal outpatient adolescent clinic. There were 383 teenagers who qualified for the study. Of these, 35% (134) reported premarital sexual activity. During the study period, 3% (8) of the 249 nonsexually active teens reported becoming sexually active. Among the 134 sexually active teens at clinic entry, 27% reported using a contraceptive method at their most recent sexual encounter. Among the 142 sexually active adolescents at the conclusion of the study, 76% reported contraceptive use at their most recent sexual encounter (p less than 0.001). We conclude that the provision of FPC to nonsexually active and sexually active teens does not appear to promote the onset of sexual activity significantly among the non-sexually active group, although it significantly increases contraceptive use among the sexually active group.

Expression of the Rous sarcoma virus env gene from a simian virus 40 late-region replacement vector: effects of upstream initiation codons

Expression of the Rous sarcoma virus envelope gene (env) from a simian virus 40 (SV40) late-region replacement vector is dependent on the position of env within the SV40 late-region sequences. The difference in expression levels appeared to be due to differences in the efficiency with which the env-specific transcripts were translated, because transcription levels from different constructions were similar. Deletion of the nucleotides encoding the agnoprotein initiator codon, located upstream of the env sequences in the poorly expressed construct, resulted in high levels of env expression. The agnoprotein initiator codon and overlapping open reading frame thus act as strong barriers to further ribosome scanning and prevent initiation at the env AUG codon. We conclude that AUG codons present in the late region of SV40 can reduce expression of inserted genes positioned downstream. Nevertheless, intrinsic properties of the gene may determine its ultimate level of expression.

Complete amino acid sequence of flavocytochrome b2 from baker's yeast

Each subunit of baker's yeast flavocytochrome b2 can be selectively cleaved by proteases into two fragments, amino-terminal fragment alpha and carboxy-terminal fragment beta. The primary structure of the former has been reported before [Ghrir, B., Becam, A. M. & Lederer, F. (1984) Eur. J. Biochem. 139, 59-74]. The amino acid sequence of the 197-residue fragment beta has now been established. The fragment was cleaved with cyanogen bromide; the three peptides thus obtained were submitted to digestions with Staphylococcus aureus V8 protease, chymotrypsin and trypsin, sometimes after succinylation. The complete fragment was also submitted to tryptic cleavage after citraconylation. Peptides were separated by thin-layer finger-printing or high-pressure liquid chromatography. They were mostly sequenced in a liquid-phase sequenator. The 511-residue amino acid sequence of the mature protein is thus completely established. Secondary structure predictions indicate an alternation of helical and extended structure, with a higher percentage of the former. Comparisons with other flavoproteins do not detect any significant sequence similarity.

Nutritional status of children in the health district of Cusco, Peru

This study was conducted to obtain an accurate assessment of the nutritional status of the children in the Cusco, Peru Health District. It is a sample survey of anthropometric measures for 3,383 children under the age of 10 yr. The results showed a significant decline in nutritional status with age (96.88% normal range at ages 1-3 mo to only 37.43% normal at ages 12-24 mo) followed by a gradual improvement in the children above 2 yr (approximately 50% normal). The deficits at the older ages were principally due to low weights-for-age. Nutritional status was also dependent on sex, village altitude, remoteness, and population size (p less than 0.005). Of these, only sex interacted with age. The girls did significantly better at some ages and the boys better, but not significantly so, at other ages.

Fertility and ovum transport after microsurgical removal of the uterotubal junction in rabbits

The role of the uterotubal junction (UTJ) in fertility and ovum transport was investigated following unilateral microsurgical resection of the UTJ in 15 rabbits. Fourteen animals became pregnant on the UTJ resected side and 14 on the control side following artificial insemination and induction of ovulation. Fifty-two of 61 ova (85.2%) became implanted on the control side, and 56 of 68 ova (82.3%) became implanted on the resected side. Ten days after delivery, artificial insemination and induction of ovulation were repeated. Ovum transport was examined at 60, 66, and 72 hours. There was no significant difference in ovum transport between UTJ resected and control sides. The distribution of ova within the oviduct and the time of their entrance into the uterus was comparable in both sides. These results indicate that the UTJ is not necessary for normal fertility and ovum transport in the rabbit.

Endoscopic myotomy in the treatment of achalasia

Seventeen patients with achalasia were treated by endoscopic myotomy limited to the esophageal rosette and avoiding the distal antireflux zone. Clinical, radiological, endoscopic, and manometric follow-up revealed improvement comparable to that seen in patients after successful surgical myotomy or pneumatic dilation. In the hands of the authors, the procedure has been simple, fast, effective, and safe, thus providing an alternative treatment of achalasia.

Mecrowear of mammalian teeth as an indicator of diet

Microwear details on teeth of two sympatric species of hyrax are correlated with major dietary differences observed in the wild. Grazing (Procavia john-stoni) and browsing (Heterohyrax brucei) species can be distinguished. The results show that diets of extinct species may be deduced from tooth microwear.

Metastatic disease of the paraspinal muscles: electromyographic and histopathologic correlation in early detection

Electromyographic examination may demonstrate severe segmental compromise of the posterior primary ramus and relative sparing of the anterior ramus as the earliest objective evidences of spinal and paraspinal metastases. Antecedent studies, including roentgenographic, radioisotopic and neurologic investigations, are often initially normal, failing to reveal the underlying cause of the progressive back pain. The present report demonstrates metastatic spread both through the paravertebral venous plexus and by direct extension in contiguous muscle. In this special instance, segmental 4+ fibrillations in the paraspinal muscles are electrophysiologic manifestations of a local, active process of denervation rather than a remote effect of the malignant disease, as has been suggested by others.

Retrograde pancreatography: new contributions

The standard technic for pancreatography was modified by using a metallic guide wire in the proximal half of the cannula so as to regulate pressure independently from that applied manually. The maximum pressure obtained by this method was measured in a polyethylene teflon cannula constructed to correspond to the Wirsung duct. Pressure was five times less when the guide wire was used. Our results in 33 patients correspond to experimental data. Only in 28% of our cases did the amylase rise slightly to a maximum of 290 Somogyi units. Acinar opacification was attempted by adding NaCO3 to a standard dye solution and was obtained in 20% of the cases (5 of 25). Maximum amylase elevation in this group was 263 Somogyi units. No complications resulted from the pressure measurements during pancreatography.

Endoscopic, radiologic and manometric correlation in small sliding hiatal hernia

Of the three methods employed, endoscopy seems to be the most accurate since it permits identification of both anatomical structures and serves as a basis for interpretation of radiology and manometry. Cardial incisura was the easiest and most constantly identifiable structure by the three methods. It must be considered as the union between esophagus and stomach. In small sliding hiatal hernia, the cardial incisura remains below the diaphragm and the gastric mucosa slides up into the chest, resulting in a partial prolapse (hiatal hernia of sliding mucosa). This concept would clarify the difference in interpretation of the most commonly used procedures in diagnosis of sliding hiatal hernia.