Evidence for the Presence of the Ascorbate-Glutathione Cycle in Mitochondria and Peroxisomes of Pea Leaves

The presence of the enzymes of the ascorbate-glutathione cycle was investigated in mitochondria and peroxisomes purified from pea (Pisum sativum L.) leaves. All four enzymes, ascorbate peroxidase (APX; EC 1.11.1.11), monodehydroascorbate reductase (EC 1.6.5.4), dehydroascorbate reductase (EC 1.8.5.1), and glutathione reductase (EC 1.6.4.2), were present in mitochondria and peroxisomes, as well as in the antioxidants ascorbate and glutathione. The activity of the ascorbate-glutathione cycle enzymes was higher in mitochondria than in peroxisomes, except for APX, which was more active in peroxisomes than in mitochondria. Intact mitochondria and peroxisomes had no latent APX activity, and this remained in the membrane fraction after solubilization assays with 0.2 M KCl. Monodehydroascorbate reductase was highly latent in intact mitochondria and peroxisomes and was membrane-bound, suggesting that the electron acceptor and donor sites of this redox protein are not on the external side of the mitochondrial and peroxisomal membranes. Dehydroascorbate reductase was found mainly in the soluble peroxisomal and mitochondrial fractions. Glutathione reductase had a high latency in mitochondria and peroxisomes and was present in the soluble fractions of both organelles. In intact peroxisomes and mitochondria, the presence of reduced ascorbate and glutathione and the oxidized forms of ascorbate and glutathione were demonstrated by high-performance liquid chromatography analysis. The ascorbate-glutathione cycle of mitochondria and peroxisomes could represent an important antioxidant protection system against H2O2 generated in both plant organelles.

Ehrlich ascites tumor cells produce a transforming growth factor-beta (TGFbeta)-like activity but lack receptors with TGFbeta-binding capacity

Ehrlich ascites tumor cells incorporate [methyl-3H]thymidine into DNA independently of exogenous growth factors or fetal calf serum. Using an acid/ethanol extraction procedure we have obtained from these tumor cells a fraction that induces both the proliferation and the formation of cell foci by Swiss 3T3 mouse fibroblasts in the presence of insulin; inhibits the proliferation of Mv1Lu mink lung epithelial cells; and stimulates the growth of NRK rat kidney fibroblasts in soft-agar in the presence of epidermal growth factor. An antibody against transforming growth factor-beta (TGFbeta) prevents both the tumor extract-induced proliferation of Swiss 3T3 fibroblasts and the tumor extract-induced proliferative arrest of Mv1Lu cells. The tumor cells secrete a TGF beta-like activity to the extracellular medium in a partially-activated form. However, authentic TGFbeta does not affect their proliferation, and no TGFbeta receptors were detected using [125I]TGFbeta as a ligand. Therefore, the absence of TGFbeta receptors with ligand-binding capacity in these tumor cells may bypass the negative control that this factor exerts on the proliferation of their normal cell counterparts.

The aminonucleoside antibiotic A201A is inactivated by a phosphotransferase activity from Streptomyces capreolus NRRL 3817, the producing organism. Isolation and molecular characterization of the relevant encoding gene and its DNA flanking regions

A novel resistance determinant (ard2) to the aminonucleoside antibiotic A201A was cloned from Streptomyces capreolus NRRL 3817, the producing organism, and expressed in Streptomyces lividans. Sequencing and subcloning experiments of a 3-kb fragment localized ard2 to an ORF of 591 nucleotides. Cell-free extracts from both S. capreolus and S. lividans (ard2) were shown to phosphorylate A201A in an ATP-dependent reaction. The resulting product (P-A201A) was purified and shown to lack any detectable biological activity against a gram-positive indicator organism. Phosphorylation by Ard2 takes place on the hydroxyl group at C2 of the unsaturated hexofuranose moiety of A201A, as shown by 1H-NMR analysis of purified P-A201A. The expression of ard2 appears to be developmentally controlled. In addition to ard2, the sequenced DNA fragment contained two incomplete ORFs (2 and 5) and one complete ORF (4), which appear to determine enzymes of the A201A biosynthetic pathway. Whereas the deduced product of ORF2 did not show any similarity to proteins in data banks, those of ORF5 and ORF4 encode putative glycosyltransferase and ketoreductase activities, respectively. ard2 and these three ORFs seem to be transcribed in a single polycistronic transcript, which supports the notion that they are a part of an A201A biosynthetic gene cluster.

High-fat sunflower and olive oil diets affect serum lipid levels in steatotic rat liver differently

This work describes the long-term effects of two different diets, one rich in olive oil and the other in sunflower oil, on serum lipid and lipoprotein levels after the establishment of fatty liver in rats 8 and 15 months old. The serum lipid and lipoprotein levels as well as the steatotic process have been evaluated by biochemical and histological methods, respectively. The results showed that fatty liver was well developed with both long-term high-fat diets, and hepatocytes were filled with many lipid droplets. This process was more evident in the portal zones, where fat hepatocytes were more numerous. Serum total cholesterol (TC) and HDL-C levels were highest in the sunflower oil fed rats, whereas the TG and LDL-C levels were highest in the olive oil group. Finally, the atherogenic indexes (HDL/TC, HDL/LDL, HDL/(TC-HDL)) were higher in the sunflower oil diet group than in the olive oil group.

The disodium salt of EDTA inhibits the binding of vasoactive intestinal peptide to macrophage membranes: endodontic implications

The purpose of this study was to investigate the effect of the disodium salt of ethylenediamine tetraacetate (EDTA), a calcium ion chelator used in the root canal therapy, on vasoactive intestinal peptide (VIP) binding to macrophage membranes (MM's). Binding assays were conducted at 15 degrees C in 0.5 ml of 50 mM Tris-HCl buffer (pH 7.5) containing 1.6% (w/v) bovine serum albumin, 1.2 mg/ml of bacitracin, and different EDTA concentrations, using 45 pM of [125I]VIP as tracer. Results showed that EDTA inhibits VIP binding to MM's in a dose-dependent manner, with an IC50 value of 5.4 mM (p < 0.01). EDTA concentrations equal or higher than 100 mM of abolished VIP-MM interaction. Taking into account that the macrophage plays an essential role in inflammatory reactions and the immune response, we conclude that the apical extrusion of EDTA during root canal therapy could modify VIP-macrophage interaction modulating the inflammatory mechanisms involved in periapical lesions.

Risk behavior and HIV seroincidence among out-of-treatment injection drug users: a four-year prospective study

We monitored trends in HIV risk behaviors and seroconversion among out-of-treatment injection drug users (IDUs) receiving street-based outreach intervention. Beginning in 1988, 641 HIV-seronegative IDUs were recruited by targeted sampling methods to reflect broader IDU populations and were followed for 4 years (1988-1992). All were active injectors not in treatment when recruited. Cohort members were targets of HIV-prevention outreach. The intervention was guided by the Indigenous Leader Outreach Model: Exaddicts deliver HIV-prevention services targeting IDU social networks in community settings. Primary outcome measures were HIV seroconversion and HIV risk behaviors. Observed incidence of HIV infection decreased, from 8.4 to 2.4 per 100 person-years. Prevalence of drug risk behaviors also decreased, from 100 to 14%. Seroconversion was associated with injection risk behavior [risk ratio (RR) = 9.8]. Sex risk behavior also decreased, but less dramatically, from 71 to 45%. Out-of-treatment IDUs in Chicago have reduced their rates of new HIV infection by reducing their injection risk behavior. New infections were strongly associated with injection risk behavior but not with sex risk behavior.

Chemopreventive effect of S-allylcysteine and its relationship to the detoxification enzyme glutathione S-transferase

Sulfur-containing substances derived from garlic and onion have been shown to prevent experimental carcinogenesis. One of the hypotheses explaining the mechanisms of the chemopreventive activity of these substances is that they activate detoxification systems such as glutathione S-transferase (GST). In this study the effects of S-allylcysteine (SAC), a water-soluble organosulfur compound derived from garlic, on GST activities in the liver, small intestine and colon were investigated. Additionally, we examined SAC for chemopreventive effects on aberrant crypt foci, which are the most likely precursors of colon cancers. In the rat colonic aberrant crypt assay administration of SAC during the initiation period decreased the number of aberrant crypt foci by 33 and 54% in groups given 40 or 80% maximum tolerated dose (MTD) of SAC respectively. The number of aberrant crypt foci, however, was not changed when SAC was given during the promotion period. GST activity in the liver was increased significantly by 41% 12 h after a single oral administration of 3.5 mmol/kg SAC and this elevated GST level was maintained over a 72 h period. GST levels were increased significantly by the administration of SAC (1.8 mmol/kg/ day for 3 days) not only in the liver but also in the proximal and middle small bowel. Isozyme levels of GST after administration of SAC were also determined using Western blotting. Hepatic GST-alpha and GST-mu were significantly increased by 35 and 42% respectively after oral administration of SAC. GST-pi levels were lower than the detection limit (130 ng/mg/protein) in both the control and SAC-treated groups. These results strongly support the previous working hypothesis that SAC exhibits chemopreventive activity by exerting specific effects on carcinogen detoxification systems.

Aberrant crypts as a biomarker for colon cancer: evaluation of potential chemopreventive agents in the rat

We assessed the effects of 41 potential chemopreventive agents in the F344 rat using the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon as the measure of efficacy. ACF were induced by the carcinogen azoxymethane in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last azoxymethane injection, animals were evaluated for the number of aberrant crypts detected in methylene blue-stained whole mounts of rat colon. The 41 agents were derived from a priority listing that was based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. The list of agents included representative examples of phytochemicals, vitamins, minerals, inhibitors of proliferation, inducers of Phase 1 and Phase 2 metabolism systems, nonsteroidal anti-inflammatory agents, and differentiation agents. Eighteen agents were positive in the assay, significantly reducing the incidence of ACF at least in one of two doses tested. As a chemical class, the nonsteroidal anti-inflammatory drugs, which included ibuprofen, ketoprofen, piroxicam, and indomethacin, were most active; other less potent agents were arginine, butylated hydroxyanisole, curcumin, diallyl sulfide, difluoromethylornithine, 18 beta-glycyrrhetinic acid, indole-3-carbinol, oltipraz, purpurin, rutin, and the sodium salts of butyrate, selenite, and thiosulfate. Twenty-three agents did not inhibit ACF; included among these were several agents that promoted the development of ACF at one or both doses tested: benzyl isothiocyanate,calcium glucarate, catechin, dihydroepiandosterone, fluocinolone acetonide,folic acid, levamisole, 2-mercaptoethanesulfonic acid, nordihydroguiaretic acid, potassium glucarate, propyl gallate, beta-sitosterol, sodium cromolyn, sodium molybdate, and sulfasalazine. The aberrant crypt assay demonstrates reasonable specificity and sensitivity in predicting which agents are likely to prevent colon cancer.

Sequence analysis of a 14.2 kb fragment of Saccharomyces cerevisiae chromosome XIV that includes the ypt53, tRNALeu and gsr m2 genes and four new open reading frames

As part of the EU yeast genome program, a fragment of 14,262 bp from the left arm of Saccharomyces cerevisiae chromosome XIV has been sequenced. This fragment corresponds to cosmid 14-14b and is located roughly 130 kb from the centromere. It contains four new open reading frames which encode potential proteins of more than 99 amino acids, as well as the ypt53, tRNALeu and gsr moffenes. The putative protein N2212 is similar to the ribosomal protein S7 from humans. N2215 contains several predicted transmembrane elements. N2231 contains regions which are rich in acidic, as well as basic, residues which could from alpha-helical structures. Similar regions are found in a variety of proteins including glutamic acid rich protein, trichohyalin, caldesmon, Tb-29 and several cytoskeleton-interacting proteins.

Diagnostic value of three tumor markers determined in pleural effusions

In order to discriminate between malignant and benign effusions, the values of tissue polypeptide specific antigen,carcinoembryonic antigen and squamous cell carcinoma associated antigen were measured in the pleural fluid of 30 patients with neoplasm, 10 with tuberculous pleurisy, 10 with transudates due to congestive heart failure or cirrhosis, 29 with parapneumonic effusions and 23 with benign diseases other than tuberculosis and pneumonia. Carcinoembryonic antigen and tissue poly-peptide specific antigen levels in effusions due to neoplasms were significantly higher than those in effusions due to other diseases. The areas under Receiver Operating Characteristic curves for carcinoembryonic antigen and tissue polypeptide specific antigen determinations were 0.69 and 0.67, respectively. No significant differences were found in the pleural fluid squamous cell carcinoma associated antigen levels between neoplasms and other diseases. The ability of tissue polypeptide specific antigen and carcinoembryonic antigen to discriminate between benign and malignant effusions may be considered comparable. Although both carcinoembryonic antigen and tissue polypeptide specific antigen showed a low accuracy (the number of undiagnosed pleural effusions is considerably high), both tissue polypeptide specific antigen and carcinoembryonic antigen determinations may contribute to a correct diagnostic classification. Moreover, the combination of these markers provides a specificity of 97.2%. However, the low number of positivities obtained for tissue polypeptide specific antigen and carcinoembryonic antigen together (13 cases in our series) reveals the need for further investigations.

Characterization of nitrobenzylthioinosine binding sites in the mitochondrial fraction of rat testis

The presence of [3H] NBMPR binding sites in the mitochondrial fraction of rat testis is described. The dissociation constant (KD) from saturation studies was 0.16 +/- 0.04 nM. The association and dissociation rate constants (k1 and k-1) were 3.95 +/- 0.57 x 10(8) M(-1) min(-1) and 0.025 +/- 0.002 min(-1), respectively. The number of binding sites was 2,100 +/- 163 fmols/mg protein. [3H] NBMPR binding was inhibited, in a nanomolar range, by NBMPR (KI= 0.23 +/- 0.02 nM), OH-NBMPR (KI= 2.30 +/- 0.55 nM) and HNBTG (KI= 2.58 +/- 0.33 nM). In the micromolar range, adenosine receptor ligands such as PIA (3.46 +/- 1.36 microM), 2-chloroadenosine (18.81 +/- 3.36 microM) and NECA (8.26 +/- 3.90 microM), and mitochondrial benzodiazepine receptor ligands such as Ro 5-4864 (5.15 +/- 1.82 micrmoM and PK 11195 inhibited the specific binding of [3H] NBMPR. These results suggest the existence of a nucleoside transport system in the mitochondrial fraction of rat testis.

Evaluation of zone electrophoresis of serum proteins performed on the Helena Laboratories rapid electrophoresis analyser

Zone electrophoresis of serum proteins is still widely performed as a routine procedure in clinical laboratories. It is used in the diagnosis and management of many disorders, e.g. monoclonal gammopathies, cirrhosis, nephrotic syndrome, acute-phase reaction, immunoglobulin deficiency and others. The aim of this work is to evaluate the analytical performance of zone electrophoresis of serum proteins carried out in the Helena Laboratories Rapid Electrophoresis analyser (REP) comparing the results with those obtained in the Olympus Hite System 200 (HS-200). The REP system employs agarose gel as support medium, the HS-200 system employs cellulose acetate and it is the routine method in our laboratory. To date, we have not found any paper that deals with the assessment of a system for performing zone electrophoresis of serum proteins in terms of comparison with another.

Factors determining the radioactivity levels of waters in the province of Cáceres (Spain)

In an extensive study of different types of water in the province of Cáceres (Spain) in order to determine their total alpha- and total beta-radioactivity contents, several factors were found to have a decisive influence on their radioactivity levels. Thus, parameters such as total hardness and pH can be determinative according to the lithological type of the aquifer or according to the subterranean or surface origin of the hydrological resource. Waters from classic lithologies, or originating from a well, possess above-average radioactivity indices, surpassing in numerous cases the indicative levels set by current Spanish legislation. In contrast, surface waters from rivers, in practically all cases, possess below-average radioactivity indices.

Intracellular expression of the monoclonal anti-ras antibody Y13-259 blocks the transforming activity of ras oncogenes

Microinjection of the anti-ras antibody Mab Y13-259 modifies ras function and can induce temporary reversion of the transformed phenotype in mutant ras-transformed cells. Intracellular production of neutralizing antibodies represents an approach to investigate the regulation of gene function. The genes coding for the heavy and light chains of Mab Y13-259 were isolated from a cDNA library. NIH3T3 cells transfected with heavy and light chain expression vectors produced functional anti-ras antibody. The production of functional antibody did not require glycosylation. To ensure that the antibody entered the cytoplasm and not the secretory pathway, the hydrophobic leader sequences of both chains were removed and replaced with synthetic initiator sequences. The modified heavy chain gene was cloned under the control of the murine sarcoma virus long terminal repeat, and the light chain gene under the control of the mouse mammary tumor virus long terminal repeat, which allows the induction of light chain expression in the presence of dexamethasone. When both heavy and light chain genes were expressed in cells with activated ras (morphologically transformed) in the presence of dexamethasone, we observed phenotypic reversion to characteristics of nontransformed cells. These experiments show that intracellular expression of antibodies can also be used as an alternative to analyze biological functions of a given protein.

The ard1 gene from Streptomyces capreolus encodes a polypeptide of the ABC-transporters superfamily which confers resistance to the aminonucleoside antibiotic A201A

A gene (ard1) encoding resistance to the aminonucleoside antibiotic A201A was cloned from Streptomyces capreolus NRRL 3817, the producing organism, and expressed in Streptomyces lividans. The gene ard1 induced antibiotic resistance that was highly specific for A201A. The nucleotide sequence of ard1 contains an open reading frame of 1677 bp. Transcription initiation was found to take place approximately 86 nucleotides preceding the ATG translation-initiation codon, indicating that ard1 is transcribed from its own promoter. The deduced protein sequence (Ard1, 558 amino acids) presents two ATP-binding domains with significant similarities to those of the ATP-binding cassette transporters (ABC-transporters) superfamily, including some that confer drug resistance in a variety of antibiotic-producing Streptomyces, other Gram-positive bacteria and eukaryotic cells. As is probably the case for most of these proteins, the mechanism of A201A resistance conferred by Ard1 is an active efflux energized by ATP hydrolysis.

Influence of stabilization occlusal splint on craniocervical relationships. Part II: Electromyographic analysis

The aim of this study was to determine the effect of stabilization occlusal splints on electromyographic (EMG) activity of sternocleidomastoid and trapezius muscles in subjects with spasm in the mentioned muscles. A full-arch maxillary stabilization occlusal splint was made for each of the 15 subjects. In the sternocleidomastoid muscle, tonic and saliva swallowing EMG activity decreased significantly with the splint, whereas maximal clenching activity did not change. In the trapezius muscle, no significant changes were observed with the occlusal splint. The different pattern in both muscles during tonic and swallowing EMG activity with the splint is attributed to differences in the synaptic inputs to the respective motoneuron pools, suggesting that a differential modulation of the motor neuron pools may exist of both muscles, of peripheral and/or central origin.

Complete DNA sequence of yeast chromosome XI

The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map demonstrate the need for using independent physical mapping criteria.

Spontaneous bovine respiratory syncytial virus infection in goats: pathological findings

This paper presents the results of a study of eight cases of natural bovine respiratory syncytial virus (BRSV) infection in a herd of 50 Murciana kids from a intensive goat-farm in Spain. Clinical and pathological analysis confirmed the existence of natural BRSV infection in eight kids. In two of the eight animals there was also evidence of concurrent infection with P. haemolytica A.

The pur8 gene from the pur cluster of Streptomyces alboniger encodes a highly hydrophobic polypeptide which confers resistance to puromycin

A novel puromycin-resistance determinant (pur8) was isolated from one end of the pur cluster that encodes the puromycin biosynthetic pathway from Streptomyces alboniger and expressed in Streptomyces lividans. The gene pur8 induced antibiotic resistance that was highly specific for puromycin. The nucleotide sequence of pur8 contains an open reading frame of 1512 bp whose deduced amino acid sequence encodes a polypeptide (Pur8) with 14 possible transmembrane-spanning segments. It shows significant similarities to other known or putative transmembrane proteins, including a number which confer drug resistance in a variety of antibiotic-producing Streptomyces, Gram-positive and Gram-negative bacteria, and some solute transporters of prokaryotic and eukaryotic origin. As is probably the case for most of these proteins, Pur8 may be involved in active puromycin efflux energized by a proton-dependent electrochemical gradient. In addition, it could be implicated in secreting N-acetylpuromycin, the last intermediate of the biosynthesis pathway, to the environment.

The complete sequence of a 15,820 bp segment of Saccharomyces cerevisiae chromosome XI contains the UBI2 and MPL1 genes and three new open reading frames

As part of the EEC yeast genome program, a fragment of 15,820 bp from the right arm of Saccharomyces cerevisiae chromosome XI has been sequenced. This fragment corresponds roughly to the centromere-distal half of cosmid pUKG046 and to a small fragment of cosmid pUKG096, which are located approximately 150 kb from the centromere. It contains four open reading frames (ORFs) which encode potential proteins of more than 100 amino acid residues, as well as the UBI2 gene which carries an intron and does not show up as an ORF in the sequence analysis programs. One of the putative proteins, YKR412, is very rich in serine and has significant homology at the carboxyl end to Nopp140 phosphoprotein. YKR413 has several predicted transmembrane domains. YKR15, which has been recently cloned as the MPL1 gene, encodes a polypeptide that shows homologies to myosin heavy chain and to the cytoskeleton protein Uso1.

Identification of the gene encoding an N-acetylpuromycin N-acetylhydrolase in the puromycin biosynthetic gene cluster from Streptomyces alboniger

The biologically inactive compound N-acetylpuromycin is the last intermediate of the puromycin antibiotic biosynthetic pathway in Streptomyces alboniger. Culture filtrates from either this organism or Streptomyces lividans transformants harboring the puromycin biosynthetic gene cluster cloned in low-copy-number cosmids contained an enzymic activity which hydrolyzes N-acetylpuromycin to produce the active antibiotic. A gene encoding the deacetylase enzyme was located at one end of this cluster, subcloned in a 2.5-kb DNA fragment, and expressed from a high-copy-number plasmid in S. lividans.

Detection of Epstein-Barr virus by polymerase chain reaction in transbronchial biopsies of lung transplant recipients: evidence of infection?

Thirty-nine paraffin-embedded transbronchial biopsies from ten lung transplant recipients were evaluated by the polymerase chain reaction for the presence of Epstein-Barr virus (EBV). Six of these patients had positive EBV serology. Nine biopsies from nine non-transplant patients with nonspecific interstitial pneumonitis were studied as a control group. Eight biopsies from four of the ten transplant patients (40%) were positive for EBV by polymerase chain reaction, utilizing 40 cycles and two sets of primers (501/502) complementary to sequences within the Bam H1 W region of the viral genome. Five of these eight positive biopsies had been diagnosed as mild acute cellular rejection based on clinicopathologic criteria. Three of the four EBV-positive patients showed clinical improvement with antiviral agents prescribed for concomitant cytomegalovirus infection. Our data demonstrate the potential of polymerase chain reaction to detect small quantities of EBV in transbronchial biopsies from lung transplant recipients. Such findings should be interpreted cautiously in the evaluation of lung transplant recipients, since EBV can be detected in the absence of a lymphoproliferative disorder or an active pneumonitis caused by this virus.

Dentures for a 3-yr-old child with ectodermal dysplasia: case report

A case of a 3-year-old boy with X-linked hypohidrotic ectodermal dysplasia is presented. Complete maxillary and mandibular dentures were made at 3 years and 2 months of age. The process for making the dentures is described. Obtaining enough patient cooperation and proper application of behavioral management techniques are critical factors for the procedure described in the article.

Effect of leukotrienes of renal water excretion

To investigate the renal actions of leukotrienes (LT), we infused arachidonic acid into the renal artery of anesthetized dogs during systemic cyclooxygenase inhibition (with ibuprofen) alone or in combination with lipoxygenase inhibition or LTD4/LTE4 receptor antagonism. Renal arachidonic acid infusion following ibuprofen alone decreased urine osmolality (945 +/- 143 to 698 +/- 144 mosm/kg; p < 0.01) and increased urine flow rate (0.34 +/- 0.11 to 0.56 +/- 0.16; p < 0.05) without altering renal blood flow, glomerular filtration rate or sodium excretion. In separate groups, prior inhibition of lipoxygenase (propylgallate) or blockade of LTD4/LTE4 receptors (LY171883) prevented the changes in urine osmolality and urine flow rate. Intrarenal oleic acid infusion following ibuprofen had no effect on renal function. Analysis of the renal papillae at the end of the experiment indicated that interstitial osmolality and sodium, potassium and urea contents were the same in all groups, ruling out a decrease in papillary interstitial osmolality as the cause of the decrease in urine osmolality in the arachidonic acid-infused group. Our experiments suggest that renal LT can decrease urine osmolality and increase urine flow rate and may play a role in renal water excretion.

Cephalometric changes in a patient with ectodermal dysplasia after placement of dentures

The purpose of this article is to analyze the changes observed in a three-year-old boy affected of ectodermal dysplasia after the placement of complete dentures. Esthetic, functional as well as cephalometric changes are discussed.

Effects on platelet aggregation and fibrinolytic activity during upright posture and exercise in healthy men

The circadian variation of acute myocardial infarction suggests that daily activities such as assuming the upright posture and performing different daily activities may trigger the onset of coronary thrombosis. Such triggering may result from unfavorable alterations in the balance between the prothrombotic and antithrombotic properties of the blood. The present study compares the effects of 2 common daily activities, assuming the upright posture and exercise, on platelet aggregation and fibrinolytic activity. In healthy male subjects, assuming the upright posture in the morning significantly increased platelet aggregation and produced only a moderate increase in fibrinolytic activity within 10 minutes. These changes were still present after 90 minutes in the upright posture. Supine posture for 45 minutes resulted in levels of fibrinolytic activity and platelet aggregation comparable to that observed before initially assuming the upright posture in the morning. Return to the supine posture for 45 minutes resulted in levels of fibrinolytic activity and platelet aggregation comparable to that observed before the initial assumption of upright posture. The changes recurred when upright posture was taken later in the day. Exercise did not increase platelet aggregation to levels beyond that produced by the upright posture, but was associated with a marked increase in fibrinolytic activity. Thus, exercise and upright posture produce distinctive alterations in the thrombogenic potential of the blood that may influence the timing of clinical vascular events.

Viability of Echinococcus granulosus cysts in mice following cultivation in vitro

The viability of hydatid cysts developed in vitro for 90 days was assessed by implantation into mice. Cysts removed from mice at 270 days post-infection (p.i.) increased their size 13.5-fold and contained several brood capsules containing protoscoleces. Thus, cysts remain viable after prolonged in vitro culture. The implantation in mice of 15 cysts developed in vitro yielded an average of 10 cysts per mouse, which is indicative of a high survival rate in these experimental infections. The ultrastructural study of cysts recovered from mice 270 days p.i. showed that the germinal membrane was more compact than before implantation and several layers of tegumental cells had developed. Observations of cysts removed from mice indicated that the plasma membrane surrounding microtriches had prolongations opening into the laminated layer.

The role of the endoscopic biopsy in the diagnosis of gastric lymphoma: a morphologic and immunohistochemical reappraisal

Forty-three endoscopic biopsies from 29 patients with confirmed gastric lymphoma (GL) were analyzed retrospectively to establish the morphologic criteria of greatest diagnostic significance. An average of 10 tissue samples was obtained at each endoscopy. In 44% of the cases, lymphoma was discovered in only one or two of the tissue portions. Eighteen lymphomas were primary, six were probably primary, and five were generalized. The diagnosis of lymphoma was originally suspected or established in 46% of the biopsies. However, a review of the histologic sections indicated that the changes, either diagnostic of or compatible with lymphoma, were present in 75% and 18% of the sections, respectively. Most diagnostic errors consisted of confusion with diffuse lymphoid infiltrates in chronic gastritis and/or peptic ulcer, and less frequently with poorly differentiated carcinoma. In those cases confused with chronic gastritis or peptic ulcer, biopsies showed centrocyte-like cells of the standard type or small lymphocytes which produced: (1) a marked increase in density of the lymphoid infiltrate in the gastric mucosa, (2) massive substitution of gastric glands by lymphoid infiltration, and (3) a collection of lymphocytes infiltrating and partially destroying isolated glands (lymphoepithelial lesion). From 48 biopsies having intense benign lymphoid infiltrates, three were interpreted (by means of a blinded study) as compatible with GL. In poorly differentiated neoplasms (blastic and pleomorphic types), cytologic features were sufficient to diagnose GL or malignant neoplasms; immunohistochemical techniques were useful to define their lymphoid nature. It is concluded that many GLs can be suspected or correctly diagnosed by routine endoscopic biopsy.

[Barodontology: current status. Dental aspects]

We present a comprehensive review of barodontalgia, with reference to the several pathogenetic hypotheses, and insisting on the consideration of barodontalgia in the differential diagnosis of toothache. The odontologists approach to this increasing clinical problem is also discussed.

Characterization of Saccharomyces cerevisiae strains displaying high-level or low-level resistance to trichothecene antibiotics

Biochemical and genetic analyses have been carried out on Saccharomyces cerevisiae strains characterized in vivo as sensitive, low-level-resistant or high-level-resistant to trichothecene antibiotics. Levels of drug resistance in vitro were determined for each strain and for suitable diploids derived from them. Ribosome biogenesis was also studied in selected haploids. It is suggested that resistance in all cases results from a mutation in the gene encoding ribosomal protein L3. If this is indeed the situation, then different mutations in this same gene not only can cause low-level or high-level resistance to trichothecene antibiotics but also can affect the maturation of either 40 S or 60 S ribosomal subunits.

Ischemic reperfusion injury in rabbit spinal cord: protective effect of superoxide dismutase on neurological recovery and spinal infarction

The potential role of superoxide dismutase (SOD), a specific superoxide anion radical scavenger, in treating spinal cord ischemia was investigated in rabbits subjected to aortic occlusion for 20 min. SOD treatment, targeted to the early reperfusion period, reduced both motor dysfunction and incidence of spinal infarcts at 7 days after ischemia. Present results suggest that oxygen-derived free radicals play a role in the pathogenesis of infarcts developing in the spinal cord after ischemia and reperfusion injuries.

Annual changes in the number, testosterone content and ultrastructure of glandular tissue cells of the testis in the marbled newt Triturus marmoratus

The testes of 8 specimens of Triturus marmoratus were collected during each month of 1987 and processed for electron microscopy and light microscopy demonstration of testosterone (T) following the ABC (avidin-biotin peroxidase complex) method. According to their staining affinity for anti-T antibodies, the glandular tissue cells were classified as T-, T+, T++, and T and the annual changes in the numbers of these cell populations, as well as in the volume occupied by the glandular tissue, were calculated. The volume occupied by the glandular tissue increases from September to December; it begins to decrease in April and disappears from June to August. The glandular tissue is formed from the interstitial cells that surround the lobules containing differentiating germ cells. During the spermatogenic process, the interstitial cells do not show staining affinity for anti-T antibodies. In August-September, the interstitial cells around the lobules that have completed spermatogenesis become positively stained (T+) and form the glandular tissue when the spermatozoa leave the testis. The numbers of intensely stained cells in the glandular tissue (T++ and T ) increase from September to November; begin to decrease in December; disappear in January-February; increase again in March and decrease again in April until they disappear in June-September. The interstitial cells, before their transformation in glandular tissue, are ultrastructurally similar to fibroblasts. After their transformation these cells increase in size and develop abundant smooth endoplasmic reticulum, mitochondria with tubular cristae and lipid droplets. This morphological pattern is maintained in the glandular tissue from September to April in spite of the changes in staining affinity during this period.

Latissimus dorsi free flap for restoration of facial contour defects

The treatment of facial asymmetries presents an aesthetic component of great importance. To correct facial contour defects, there are many therapeutic possibilities available, such as autologous tissue grafts and inorganic implants. The arrival of microsurgical techniques has improved the outlook for facial contour restoration. Among the tissues used are groin, escapular, and omentum flaps. This article introduces our experience with the latissimus dorsi free flap for the restoration of facial contour defects. Our experience is based on 7 patients affected with hemifacial microsomia and Romberg's disease. Operative planning, surgical procedure, and results are described. The use of the latissimus dorsi free flap is our procedure of choice for its greater adaptability in conforming to the shape of the defect, its long vascular pedicle, the abundance of available tissue, and minimal tendency to ptotic changes. At present we recommend this technique for replacement of soft tissue in severe defects of the face.

Premature centromere division dominantly inherited in a subfertile family

An increased frequency of mitoses showing premature centromere division (PCD) in every chromosome was found in lymphocyte cultures from four members of a subfertile family. These cells were observed in both the presence and absence of colchicine. Cultured fibroblasts from the proband showed only normal diploid metaphases. PCD cells seemed to have a shorter cell cycle. The anomaly was transmitted in a way compatible with autosomal dominant inheritance in this family.

Biosynthesis of puromycin by Streptomyces alboniger: characterization of puromycin N-acetyltransferase

Puromycin N-acetyltransferase from Streptomyces alboniger inactivates puromycin by acetylating the amino position of its tyrosinyl moiety. This enzyme has been partially purified by column chromatography through DEAE-cellulose and Affigel Blue and characterized. It has an Mr of 23 000, as determined by gel filtration. In addition to puromycin, the enzyme N-acetylates O-demethylpuromycin, a toxic precursor of the antibiotic, and chryscandin, a puromycin analogue antibiotic. The Km values for puromycin and O-demethylpuromycin are 1.7 and 4.6 microM, respectively. The O-demethylpuromycin O-methyltransferase from S. alboniger, which apparently catalyzes the last step in the biosynthesis of puromycin [Rao, M. M., Rebello, P. F., & Pogell, B. M. (1969) J. Biol. Chem. 244, 112-118], also O-methylates N-acetyl-O-demethylpuromycin. The Km values of the methylating enzyme for O-demethylpuromycin and N-acetyl-O-demethylpuromycin are 260 and 2.3 microM, respectively. These findings suggest that O-demethylpuromycin, if present in S. alboniger, would be N-acetylated and then O-methylated to be converted into N-acetylpuromycin. It might even be possible that N-acetylation of the puromycin backbone takes place at an earlier precursor.

Pseudoisodicentric bisatellited extra marker chromosome (tetrasomy 22pter----q11, trisomy Yqh), derived from a maternal Y/22 translocation. Association between this tetrasomy and "cat eye" phenotypical features

A patient with multiple congenital anomalies suggestive of the "Cat eye" syndrome was found to have an extra marker bisatellited chromosome 22 derived from a maternal Y/22 translocation, identified by multiple banding patterns in cultures treated with DA. The proband's karyotype is 47,XX, + psu idic(22)(Yqter----Yq12::22p13----22q11::++ +22q11----22p13::Yq12----Yqter), t(22;Y)(p13;q12)mat., being tetrasomic for 22pter----q11, and trisomic for Yqh. Similarity between his clinical features and reported "Cat eye" cases, confirms that this region is responsible for the phenotypical expression of the syndrome.

Cytogenetic and clinical findings in ten 45,X/46,XY patients

We report ten cases with 45,X/46,XY karyotype. Cytogenetic and clinical findings have been compared. No constant relationship was found either between blood and gonadal karyotype, or between karyotype and gonadal morphology.

Gas chromatographic determination of quazepam and two major metabolites in human plasma

Two rapid, sensitive, and specific gas chromatographic (GC) methods for the quantitative determination of quazepam (I), 7-chloro-5-(2-fluorophenyl-1,3-dihydro-1-(2,2,2-trifluoroethyl) -2H-1,4-benzodiazepine-2-thione, and its major active plasma metabolites, the 2-oxo compound (II) and the dealkylated oxo compound (III), have been developed; the first measures I and II and the second measures III. The compounds are extracted from plasma with toluene and quantitated by electron-capture detection using the internal standard method. The methods are capable of quantitating plasma levels of I and II as low as 0.75 ng/mL and plasma levels of III as low as 1.5 ng/mL. Correlation coefficients of standard curves were greater than 0.9995 for all compounds. Precision of the methods was measured at two different concentrations for each compound; the CV values were 3-6% for all three compounds. The recovery of all compounds was greater than 80%, and the ratio of recovery of each compound to that of its internal standard did not vary at different concentrations, indicating appropriate internal standards have been selected for the methods. Quazepam metabolites, other benzodiazepines, and drugs which are potential comedication do not interfere with either method. The methods were shown to be suitable for investigating the bioavailability and pharmacokinetics of quazepam at therapeutic doses.

Quantitative relationship between light intensity and luteinizing hormone surges in ovariectomized rats treated with estrogen

The purpose of this study was to determine if patterns of gonadotropin secretion during estrogen-induced luteinizing hormone (LH) surges are altered by abrupt changes in light exposure. When light intensity was increased approximately threefold, before the "critical period" or during the rising phase of the LH surge, serum LH increased significantly (P less than 0.01) compared to control values. Furthermore, LH surges were prolonged when exposure to light of high intensity was continued beyond the normal extent of the photophase. In contrast to the effects of increased light intensity, acute darkness did not alter the magnitude of LH surges compared with controls exposed to light of low intensity. Thus, phasic LH secretion is enhanced by abrupt increases in light intensity, and the duration of LH secretion can be extended by prolonging the photophase. Although LH surges occur in total darkness, this study suggests that light modulates the intensity of the signal for LH secretion by a stimulatory action.

A new patient with dicarboxylic aciduria suggestive of medium-chain Acyl-CoA dehydrogenase deficiency presenting as Reye's syndrome

A new patient with medium-chain dicarboxylic aciduria and suberyl glycinuria during an attack of acute illness is reported. When, inadvertently he was given medium-chain triglycerides for 2 days, the excretion of abnormal metabolites of medium-chain fatty acids increased and hepatomegaly became more pronounced. During remission a low excretion of the metabolites were observed. After 16 h of fasting hypoglycaemia was accompanied by an increase of urinary dicarboxylic acids and psi-hydroxyacids similar to that found on admission. Interestingly this urinary organic acid pattern persisted 8 h after intravenous administration of glucose. In a blood sample obtained after 16 h of fasting there was hypoketonaemia and increased levels of total free fatty acids, octanoic, decanoic and cis-4-decenoic acids. These biochemical data suggest the existence of a deficiency at the level of medium-chain acyl-CoA dehydrogenase.

A modified enzymatic-isotopic microassay for serotonin (5HT) using 5HT-N-acetyltransferase partially purified from Drosophila

Serotonin-N-acetyltransferase (EC 2.3.1.5), partially purified from Drosophila melanogaster (DNAT) was substituted for rat liver enzyme (RNAT) in a previously published radioenzymatic assay for serotonin (5HT). The purpose was to determine if this modification would increase the sensitivity and reliability of the original assay. Compared with RNAT, DNAT is 3-4 times more active; it lacks secondary 5HTP decarboxylase activity; and it is more stable. Under conditions of the modified assay, the only radioactive product formed from hypothalamic tissue extracts is 3H-melatonin; which can be measured from as little as 15 pg of serotonin substrate. Thus, substitution of DNAT for RNAT improves the original radioenzymatic assay allowing measurement of endogenous 5HT in hypothalamic nuclei from individual animals.