Phylogeny of trypanosomes as inferred from the small and large subunit rRNAs: implications for the evolution of parasitism in the trypanosomatid protozoa

Sequences of the small rRNA genes and partial sequences of the large rRNA genes were obtained by PCR amplification from a variety of vertebrate trypanosomes. The trypanosome species and hosts included Trypanosoma avium from a bird, T. rotatorium from an amphibian, T. boissoni from an elasmobranch, T. triglae from a marine teleost and T. carassii from a freshwater teleost. Phylogenetic relationships among these species and other representatives of the family Trypanosomatidae were inferred using maximum likelihood, maximum parsimony and evolutionary parsimony. The trypanosomatid tree was rooted using rRNA sequences from two species from the suborder Bodonina. All methods showed that the mammalian parasite, Trypanosoma brucei, constitutes the earliest divergent branch. The remaining trypanosomes formed a monophyletic group. Within this group, the bird trypanosome was grouped with T. cruzi, while the elasmobranch trypanosome and the two fish trypanosome species formed a group with an affinity to T. rotatorium. Our results provide no evidence for co-evolution of trypanosomatids and their hosts, either vertebrate or invertebrate. This suggests that evolution of trypanosomatids was accompanied by secondary acquisitions of hosts and habitats.

Kidney Stone Center of the Pacific. Summary of operations 1986 to 1993

The history and operational results in the six years since the Kidney Stone Center of the Pacific opened in 1986 are summarized and compared to the published literature, with particular attention to Hawaii's unique racial composition. We hope that the results will enable us to improve our management of stones in the future.

Organization and complexity of minicircle-encoded guide RNAs in Trypanosoma cruzi

The previously observed extensive sequence heterogeneity of the kinetoplast minicircle DNA in Trypanosoma cruzi, both intra- and interstrain, has raised the question as to how the minicircle DNA in this species can have any guide RNA (gRNA)-coding capacity at all, because there do not appear to be any variable-region sequences conserved between different strains. To address this question, we obtained the complete edited sequence of maxicircle unidentified reading frame 4 mRNA and identified 25 cognate gRNAs from gRNA libraries constructed from two clonal strains of T. cruzi--Sylvio X10/CL1 and CAN III/CL1. Libraries of PCR-amplified minicircle-variable regions were also constructed for both strains. A single gene for each gRNA was identified in the same polarity within specific minicircle-variable regions from both strains, 60-100 nt downstream from the conserved 12mer sequence. GTP-capped total gRNA from one strain failed to cross-hybridize with minicircle DNA from the other strain. The explanation for this proved to be the number of polymorphisms, mainly transitions, within the homologous gRNAs in the two strains. In most cases, these transitions did not destroy the edited mRNA/gRNA base pairing, as a result of the allowed G-U wobble base pairing. The sequences of the variable regions containing homologous gRNAs in the two strains probably derived from an ancestral sequence, and each has accumulated sufficient polymorphisms so as not to allow hybridization. Within a strain, multiple redundant gRNAs were identified that encode identical editing information but have different sequences.

Erythrocyte insulin and insulin-like growth factor-I receptor tyrosine kinase activity in hypertension in pregnancy

We have shown that preeclampsia is associated with insulin resistance. In the present study, we examined young normal, preeclamptic (PE), and gestational hypertensive (GH) nulliparous African-American women at term to investigate cellular determinants of this resistance and insulin and insulin-like growth factor-I (IGF-I) binding to partially purified erythrocyte receptors and receptor tyrosine kinase activity (TKA). Blood pressure was significantly elevated in PE and GH subjects as compared with controls. Insulin binding was similar in number and affinity in the three groups (femtomoles per microgram). IGF-I binding was increased in PE subjects as compared with either normals or GH subjects (0.2 +/- 0.02, 0.15 +/- 0.01, and 0.14 +/- 0.02 fmol/microgram protein). Insulin receptor TKA was increased in PE subjects as compared with normals when assessed either per microgram protein or per femtomole insulin binding (P < .01). In contrast, IGF-I-potentiated TKA was elevated in PE subjects only when assessed per microgram protein (P < .03). Thus, the increased number of IGF-I receptors in erythrocytes of PE subjects yields a net increase in receptor tyrosine kinase. Also, there is an augmentation of insulin receptor TKA in PE subjects. Together, these two alterations may be a compensatory mechanism for the insulin resistance associated with hypertensive diseases of pregnancy.

Minicircle-encoded guide RNAs from Crithidia fasciculata

Although the mitochondrial uridine insertion/deletion, guide RNA (gRNA)-mediated type of RNA editing has been described in Crithidia fasciculata, no evidence for the encoding of gRNAs in the kinetoplast minicircle DNA has been presented. There has also been a question as to the capacity of the minicircle DNA in this species to encode the required variety of gRNAs, because the kinetoplast DNA from the C1 strain has been reported as essentially containing a single minicircle sequence class. To address this problem, the genomic and mature edited sequences of the MURF4 and RPS12 cryptogenes were determined and a gRNA library was constructed from mitochondrial RNA. Five specific gRNAs were identified, two of which edit blocks within the MURF4 mRNA, and three of which edit blocks within the RPS12 mRNA. The genes for these gRNAs are all localized with identical polarity within one of the two variable regions of specific minicircle molecules, approximately 60 bp from the "bend" region. These minicircles were found to represent minor sequence classes representing approximately 2% of the minicircle DNA population in the network. The major minicircle sequence class also encodes a gRNA at the same relative genomic location, but the editing role of this gRNA was not determined. These results confirm that kinetoplast minicircle DNA molecules in this species encode gRNAs, as is the case in other trypanosomatids, and suggest that the copy number of specific minicircle sequence classes can vary dramatically without an overall effect on the RNA editing system.

RNA-protein interactions in the ribonucleoprotein T-complexes in a mitochondrial extract from Leishmania tarentolae

We have investigated protein-RNA interactions and the incorporation of [alpha-32P]UTP into the guide RNA and mRNA components of the 'T-complexes' in a mitochondrial extract from Leishmania tarentolae. The terminal uridylyl transferase-containing complex T-IV is probably involved in the maturation of the 3'-oligo(U) tail of the gRNAs, but the biological function and biochemical nature of the remaining T-complexes is not known. We have found that the relative extent of labeling of the RNA components is dependent on the UTP concentration: at low levels, the main endogenous RNA components labeled are the gRNAs in T-IV; at higher levels, the mRNAs in all of the T-complexes are preferentially labeled. We also show a tentative correlation in the migration pattern of UTP-labeled T-complexes and complexes which bind exogenous labeled RNA. The relative extent of binding to specific complexes is dependent upon the type of RNA. Most of the interactions between the labeled RNAs and proteins can be disrupted by heparin or a large excess of rRNA, but two labeled complexes were resistant to competition. Most of the binding of labeled exogenous gRNA is disrupted by competition with a large excess of rRNA, but predigestion of the extract with micrococcal nuclease and saturation with rRNA uncovered a high affinity complex, which involves at least two proteins interacting with the bound gRNAs. A knowledge of the RNA and protein components may aid in understanding the biological roles of these RNP complexes.

Characterization of two nuclear-encoded protein components of mitochondrial ribonucleoprotein complexes from Leishmania tarentolae

Two mitochondrial proteins with molecular masses of 18 and 51 kDa were isolated from Leishmania tarentolae, and N-terminal amino-acid sequences were obtained. The cDNAs and genes encoding these proteins were cloned using RT-PCR. The proteins were identified as components of the previously characterized mitochondrial ribonucleoprotein complexes, T-Ia and T-VI, by comigration in native gels. The p18 and p51 genes contain 17 and 9-amino-acid N-terminal sequences, which are not present in the mature proteins and may represent cleavable mitochondrial targeting sequences. There are two identical p18 genes separated by 1.7 kb in tandem array and both are transcribed. The p18 amino-acid sequence is not similar to any sequence in the database. Antiserum to p18 expressed in Escherichia coli reacts with the entire tubular mitochondrion. The p51 gene is single copy, and the amino-acid sequence is similar to mitochondrial aldehyde dehydrogenases from other organisms. The N-terminal amino-acid sequences of 71 and 62-kDa mitochondrial proteins which co-migrated in native gels with several other T-complexes were also obtained. The p71 sequence proved to be similar to hsp70 sequences from other organisms. The p62 sequence was identical to an hsp60 sequence from Trypanosoma brucei.

Caffeine enhances doxorubicin cardiac toxicity in an animal model

Based on in vitro data suggesting an interaction between methylxanthines and doxorubicin in regulating Ca2+ across muscle sarcoplasmic reticulum, this study was designed to test the hypothesis that a commonly used methylxanthine, caffeine, might influence the cardiac toxicity of doxorubicin. Three days following doxorubicin treatment, in vivo intracardiac pressures, cardiac outputs, in vitro cardiac weights, and cardiac electron microscopy were performed. Guinea pigs were treated with doxorubicin alone, doxorubicin plus caffeine, caffeine alone, and sterile saline as a control measure. Animals treated with doxorubicin had no significant differences in in vivo hemodynamics compared to the control animals. The average histology score was slightly but not statistically greater than the control animals, score (1.19 +/- 0.36 vs 1.60 +/- 0.34, respectively, P = NS). Animals receiving both doxorubicin and caffeine compared to the control animals had important differences in left ventricular systolic pressure (67 +/- 10 vs 92 +/- 7 mmHg; P = .003), cardiac output (154 +/- 35 vs 217 +/- 41 mL/min; P = .0174), stroke volume (.59 +/- 12 vs .79 +/- .07 mL; P = .0045), and histology score (2.36 +/- 0.21 vs 1.19 +/- 0.36; P = .028). There were no differences in left or right heart filling pressures between treatment groups. As an independent confirmation, there was a weak but statistically significant negative correlation between the biopsy score and cardiac output or stroke volume for all four groups of animals (r = .44, P = .031 and r = -.42, P = .040, respectively). These data are consistent with caffeine and doxorubicin having additive or potentiating effects on cardiac toxicity in this animal model.

In vitro RNA editing-like activity in a mitochondrial extract from Leishmania tarentolae

A mitochondrial extract from Leishmania tarentolae directs the incorporation of uridylate (U) residues within the pre-edited domain of synthetic cytochrome b (CYb) and NADH dehydrogenase subunit 7 mRNA. This has several characteristics of an in vitro RNA editing activity, but no direct evidence for involvement of guide RNAs was obtained. Inhibition by micrococcal nuclease suggests a requirement for some type of endogenous RNA. The limitation of internal U-incorporation to the pre-edited region in the CYb mRNA and the inhibition by deletion or substitution of both mRNA anchor sequences for CYb gRNA-I and -II could be consistent either with a gRNA-mediated process or a secondary structure-mediated process. A low level of incorporation of [alpha-32P]CTP occurs at the same sites as UTP. Internal U-incorporation activity is selectively inhibited by heterologous RNAs, suggesting an involvement of low affinity RNA-binding proteins which can be competed by the added RNA.

The role of social change in preventing low birth weight

The authors of this article examine the relationship between social factors and low birth weight and the ways in which disparities in socioeconomic status have been addressed over time. The evidence regarding the effectiveness of various efforts to influence birth weight by mitigating the consequences of disadvantage are also assessed. Low socioeconomic status has been shown to influence low birth weight through its various correlates. Historically and today, most programs and policies directed at low birth weight prevention attempt to address the individual health consequences of economic and social disadvantage. By and large, these efforts have produced mixed results. Efforts to affect low birth weight by addressing the underlying causes of social and economic disadvantage have been similarly inconclusive, reflecting the paucity of research on the subject, as well as the historical and ongoing failure to make the research link between health and social policy. The authors argue that reducing persistent disparities in low birth weight requires several steps, including embracing a broader definition of health which incorporates social dimensions, recasting the focus of research and interventions from pregnancy outcomes and infant health exclusively to include the notion of women's health more globally, expanding the research agenda to unravel the paradox of socioeconomic factors and health, and pursuing a dedicated, national commitment to assuring adequate support to individuals and families, including both adequate income and health care.

Disruption of RNA editing in Leishmania tarentolae by the loss of minicircle-encoded guide RNA genes

RNA editing in kinetoplastids appears to be a labile genetic trait that is affected by prolonged cell culture. The transcripts of the G1-G5 cryptogenes are pan-edited in the recently isolated LEM125 strain of Leishmania tarentolae, but not in the UC strain which has been in culture for 55 years. At least 32 minicircle-encoded guide RNAs (gRNAs) for the editing of G1-G5 transcripts are present in LEM125 and absent in UC. We hypothesize that specific minicircle sequence classes encoding gRNAs for the editing of these transcripts were lost during the long culture history of the UC strain. The protein products, which include components of complex I of the respiratory chain, are probably not required during the culture stage of the Leishmania life cycle.

Ancient origin of RNA editing in kinetoplastid protozoa

A rooted phylogenetic tree of the kinetoplastid protozoa has been constructed that, together with a comparative analysis of editing of several genes, leads to the surprising conclusion that extensive or pan-editing with multiple overlapping guide RNAs is more ancient than 5'-editing. The mechanism of editing is still uncertain, but multiple ribonucleoprotein complexes have been identified that contain components of the enzymatic machinery.

RNA editing and mitochondrial genomic organization in the cryptobiid kinetoplastid protozoan Trypanoplasma borreli

The bodonids and cryptobiids represent an early diverged sister group to the trypanosomatids among the kinetoplastid protozoa. The trypanosome type of uridine insertion-deletion RNA editing was found to occur in the cryptobiid fish parasite Trypanoplasma borreli. A pan-edited ribosomal protein, S12, and a novel 3'- and 5'-edited cytochrome b, in addition to an unedited cytochrome oxidase III gene and an apparently unedited 12S rRNA gene, were found in a 6-kb fragment of the 80- to 90-kb mitochondrial genome. The gene order differs from that in trypanosomatids, as does the organization of putative guide RNA genes; guide RNA-like molecules are transcribed from tandemly repeated 1-kb sequences organized in 200- and 170-kb molecules instead of minicircles. The presence of pan-editing in this lineage is consistent with an ancient evolutionary origin of this process.

Characterization of two classes of ribonucleoprotein complexes possibly involved in RNA editing from Leishmania tarentolae mitochondria

The molecular mechanism of RNA editing in trypanosomatid mitochondria is an unsolved problem. We show that two classes of ribonucleoprotein complexes exist in a mitochondrial extract from Leishmania tarentolae and appear to be involved in RNA editing. The 'G' class of RNP complexes consists of 170-300 A particles which contain guide RNAs and proteins, show little terminal uridylyl transferase (TUTase) activity and exhibit an in vitro RNA editing-like activity. The 'T' class consists of approximately six RNP complexes, the endogenous RNA of which can be self-labeled with [alpha-32P]UTP. The most abundant T complex, T-IV, is visualized by electron microscopy as 80-140 A particles. This complex exhibits TUTase activity in the native gel and contains guide RNAs. Both G and T complexes are possibly involved with RNA editing in vivo. These results are a starting point for the analysis of the biochemistry of RNA editing.

Evolution of RNA editing in kinetoplastid protozoa

The editing of RNA in trypanosomatid mitochondria involves the insertion and occasional deletion of uridine residues within coding regions of maxicircle messenger RNA transcripts. The extent to which the transcripts of homologous genes undergo editing differs in different species. In some, entire genes are edited (pan-editing), whereas in others, editing is limited to the 5' termini of editing domains (5' editing). Here we investigate which type of editing is ancestral and which is derived, by analysing RNA editing in the different lineages, using a kinetoplastid phylogeny reconstructed from nuclear small subunit ribosomal RNA sequences. We conclude that the ancestral cryptogenes were pan-edited, and we hypothesize that the 5'-edited homologues were generated by several independent events from partially edited RNAs, in which case editing may be a more primitive mechanism than previously thought.

Prenatal care needs assessment comparing service use and outcomes in Fresno, CA

The authors performed a prenatal care needs assessment for Fresno County, CA, using data from a sample of 11,878 birth certificates for the county for 1989. Birth records, patterns of prenatal care utilization, and low birth weight outcomes in the county were compared with those in a random sample of 11,826 certificates derived from births in the remainder of the State. Bivariate techniques were used in calculating care utilization rates. Multivariate logistic regression analysis was used in associating rates of prenatal care visits and gestational month of initiation of prenatal care with low weight birth outcomes. County women entered prenatal care as early as women in the remainder of the State, but did not return as often for prenatal care visits. Their rate of return for followup visits was 29.9 percent, compared with 24.8 percent for women in all other counties (P < 0.001). County women with the lowest rates of visits had 1.4 to 1.9 times the risk of having a low weight birth than other county women with higher rates of visits, and a significantly higher risk than for women of all other counties. An intensive visit schedule for high-risk care was provided 28.9 percent of county women, compared with 33.0 percent of women in all other counties (P < 0.001). County women who received a high-risk intensive visit schedule were 2.5 times more likely to have a low weight birth than county women who did not receive the schedule. For all other women in the State, the comparable risk was 2.1 times. Improvements in the number and content of prenatal care visits were shown to have a high likelihood of substantially improving birth weight outcomes for pregnancies among Fresno County women.

Detection of Trypanosoma cruzi in blood specimens of chronic chagasic patients by polymerase chain reaction amplification of kinetoplast minicircle DNA: comparison with serology and xenodiagnosis

A panel of 114 blood samples from chronic chagasic patients and nonchagasic patients was screened for Trypanosoma cruzi by xenodiagnostic, serologic, and polymerase chain reaction (PCR) amplification tests. Blood samples were preserved in a guanidine-EDTA buffer, and total blood DNA was isolated after chemical nuclease cleavage with 1,10-phenanthroline-copper ion and used as a template for PCR amplification of the conserved and variable regions of T. cruzi minicircle molecules. The PCR products were screened by Southern blot hybridization with a digoxigenin-labeled oligonucleotide probe specific for the conserved region of the minicircle. The method showed a sensitivity of 100% compared with the serologic test. In addition, all of the serology-positive, xenodiagnosis-negative samples were positive by PCR. This demonstrates that PCR amplification of T. cruzi kinetoplast minicircle DNA could replace xenodiagnosis for evaluation of parasitemia in chronic chagasic patients and could serve as a complement for serologic testing in the screening of blood bank donors.

Organization of mini-exon and 5S rRNA genes in the kinetoplastid Trypanoplasma borreli

Mini-exon gene repeats from Trypanoplasma borreli, which belongs to the Cryptobiidae family of the Bodonina suborder of the Kinetoplastida, were isolated by PCR amplification and cloning. The presence of kinetoplastid-like mini-exon genes in T. borreli is consistent with the taxonomic status of this organism as a kinetoplastid protozoan. Two families of repeats were found: 597 nt (T1) and 794 nt (T2), each of which encodes an approximately 95-nt medRNA transcript. The T1 repeats also contain a complete 5S rRNA gene on the complementary strand. The T2 repeats contain a defective copy of a 5S gene, in which the 5' portion is absent. The intergenic regions between the 5'-ends of the mini-exon genes and the 5S rRNA genes in the T1 and T2 repeats are highly diverged. All or most mini-exon genes and 5S genes are located within either the T1 or the T2 repeats. The T1 repeats were localized to a megabase-size chromosome, while the T2 repeats were localized within at least 4 large chromosomes.

Hyperinsulinemia, insulin resistance, and hyperglycemia: contributing factors in the pathogenesis of hypertension and atherosclerosis

Subtle abnormalities of carbohydrate metabolism and overt diabetes mellitus are both associated with a substantial increase in the prevalence of hypertension and the accelerated development of atherosclerosis. Hypertension is also a presumed independent risk factor for atherosclerosis, although some of the atherogenic properties of hypertension may be related to the recently recognized subtle metabolic abnormalities commonly found in persons with essential hypertension. The results of epidemiologic studies suggest that the elevated fasting and postprandial insulin levels that often occur in patients with essential hypertension, as well as in patients with type II diabetes mellitus, are an independent risk factor for atherosclerotic cardiovascular disease. Elevated glucose levels in patients with diabetes and hypertension appear to contribute to the acceleration of atherosclerosis, perhaps through toxic effects on the vascular endothelium. Other cardiovascular risk factors that are accentuated in persons with carbohydrate intolerance and hypertension include abnormalities in platelet function, clotting factors, the fibrinolytic system, and dyslipidemia. The goals of both nonpharmacologic and pharmacologic therapy for patients with abnormal carbohydrate metabolism and hypertension are to decrease cardiovascular risk as well as lower blood pressure.

Results of directional peripheral atherectomy with reference to histology, histochemistry, and ultrastructure

One hundred patients with symptomatic peripheral vascular disease were treated with a directional atherectomy catheter; 153 lesions comprising 98 stenoses and 55 occlusions were located in the iliac (n = 22), superficial femoral (n = 114), popliteal (n = 16), and anterior tibial (n = 1) arteries. The majority of these patients were poor candidates for balloon angioplasty because of the complexity of lesions. There were 70 eccentric and 28 concentric lesions and 55 occlusions (mean length 4.2 +/- 2.9 cm). Acute success rate was 94% for both stenoses and occlusions. Four patients were treated in both lower extremities. The stenoses were reduced from 85 +/- 12% to 12 +/- 10% acutely (occlusions 100% to 9 +/- 9%). Six-month angiographic follow-ups were performed in 81% of treated patients, the others refusing angiography. Mean stenosis after six months was 33 +/- 25% (occlusions 44 +/- 28%). Restenosis (> 50%) was found in 20% of treated lesions: 26% in concentric lesions, 8% in eccentric lesions, and 32% in occluded vessels. Treatment of peripheral vascular disease with the atherectomy device is safe and effective therapy with good long-term results. These results were obtained in complex lesions with 55 occlusions. Atherectomy seems to be particularly beneficial in the treatment of eccentric and complex stenoses and is not limited by occlusion or calcification. Furthermore, insight into the pathogenesis of arteriosclerosis and the development of restenosis is enabled by analysis of removed plaque material.

Postpartum abnormalities of carbohydrate and cellular calcium metabolism in pregnancy induced hypertension

We have previously reported that young, primigravid, African-American women who developed preeclampsia exhibited insulin resistance (elevated fasting insulin:glucose ratios) and abnormal intracellular free calcium ([Ca2+]i) metabolism as early as the second trimester of pregnancy. To determine if these abnormalities persist postpartum (suggesting a genetic link), we evaluated the effects of an oral glucose load (50 g) on plasma and glucose insulin, basal platelet [Ca2+]i and platelet [Ca2+]i responses to arginine vasopressin (AVP). The study population consisted of nine, young, primigravid, African-American women at 43 +/- 12 weeks postpartum from pregnancy induced hypertensive (PIH) gestations and 10 age- and weight-matched African-American women who were 29 +/- 7 weeks postpartum from normal pregnancies. The PIH group consisted of five subjects who were preeclamptic and four subjects with gestational hypertension. Baseline fasting body weights, body mass indices, plasma glucose, plasma insulin, basal platelet [Ca2+]i, and platelet [Ca2+]i responses to AVP were similar in the postpartum PIH and control groups. The oral glucose load had no effect on basal platelet [Ca2+]i levels in either group. However, plasma glucose and insulin and platelet [Ca2+]i responses to AVP were accentuated at 30 min following an oral glucose load suggesting a subtle abnormality of carbohydrate and [Ca2+]i metabolism that persists in individuals with pregnancy induced hypertension. Long term studies involving African-American populations will be necessary to determine if these metabolic abnormalities are associated with an increased propensity to hypertension.

Ozone inhalation stimulates expression of a neutrophil chemotactic protein, macrophage inflammatory protein 2

Short-term exposure of humans and animals to ozone results in increased lung neutrophils; however, the mechanisms underlying this response are not completely understood. We examined the potential involvement of the neutrophil chemotactic factor, macrophage inflammatory protein 2 (MIP-2), in ozone-induced inflammation. Exposure-response relationships for ozone and MIP-2 expression were characterized by exposing C57B1/6 mice to 0.1-2 ppm ozone for 3 hr and determining lung levels of MIP-2 mRNA 6 hr after exposure. Temporal relationships between ozone and MIP-2 were determined by exposing mice (2 ppm ozone x 3 hr) and characterizing MIP-2 mRNA expression 0, 2, 6, and 24 hr after exposure. Neutrophils in lung lavage fluid were determined in both exposure-response and time course studies. Ozone concentrations > or = 1.0 ppm increased MIP-2 mRNA and this increase corresponded with recruitment of neutrophils. MIP-2 mRNA was increased immediately after ozone exposure and decreased to control levels by 24 hr. To examine the role of direct oxidant effects in ozone-induced MIP-2 expression, alveolar macrophages were exposed in vitro for 4 hr to 10(-10)-10(-5) M hydrogen peroxide and MIP-2 expression was characterized. MIP-2 mRNA levels in lung macrophages were increased by > or = 10(-9) M hydrogen peroxide. In summary, our findings suggest the chemotactic protein MIP-2 may be responsible, at least in part, for ozone-induced increases in lung neutrophils and indicate that direct exposure of alveolar macrophages to an oxidant is sufficient to induce MIP-2 expression.

Effects of weight reduction on cellular cation metabolism and vascular resistance

The early stages of weight loss are associated with a reduction in blood pressure, and the mechanisms mediating this reduction remain unclear. Platelet free calcium levels, [Ca2+]i, have been reported to be elevated in essential hypertension and to decrease with pharmacological treatment of the hypertension. In the current study, 18 obese subjects had measurements of blood pressure, forearm blood flow, forearm vascular resistance, and both basal platelet [Ca2+]i and [Ca2+]i responses to vasopressin during 12 weeks on a very low calorie (3,360 kJ, or 800 kcal) diet. Weight reduction was associated with reduction in mean arterial blood pressure at 3-4 weeks. There were associated reductions in forearm vascular resistance and platelet [Ca2+]i as well as increases in forearm blood flow at 3-4 weeks of the diet. Increased forearm blood flow was correlated with weight loss. Vasopressin-induced platelet [Ca2+]i responses increased, which correlated with the reduction in mean arterial pressure at 7-8 weeks of weight loss. Assuming that platelet [Ca2+]i metabolism reflects vascular smooth muscle cell [Ca2+]i metabolism, the data suggest that blood pressure reduction after weight loss may be related to reduced vascular smooth muscle cell [Ca2+]i. The reason for the increased vasopressin-induced [Ca2+]i after weight reduction is unclear.

Effects of three colors in an office interior on mood and performance

This study examined the effects of three hues on subjects' performance and mood while in an office work environment for 1 hour. Pretest/posttest measurements were completed. Work performance was measured using words typed, typing errors, and a ratio of errors to words typed. Anxiety, depression, and arousal were measured by the Eight State Questionnaire of Curran and Cattell. A total of 45 women, ages 18 to 24 years, were tested individually in a single office space: 15 when the office walls were painted red/warm, 15 when walls were blue-green/cool, and 15 when walls were white/neutral. Analysis of covariance of posttest measurements with the pretest as a covariate showed no significant differences among the three groups on performance or scores on anxiety, depression, and arousal. If color of the environment has an effect on work performance or mood, either the effect was too small to be detected with samples of 15 subjects or longer participation than one hour was required.

Formation of guide RNA/messenger RNA chimeric molecules in vitro, the initial step of RNA editing, is dependent on an anchor sequence

Synthetic pre-edited messenger RNA (mRNA) and guide RNA (gRNA) for the 5'-edited maxicircle-encoded ND7 cryptogene from Leishmania tarentolae formed chimeric molecules upon incubation in the presence of a mitochondrial extract. These chimeric molecules consisted of the gRNAs covalently linked to the mRNAs by short oligo(U) tails at normal editing sites in most cases. Unlike the previously reported chimeras present in steady-state kinetoplast RNA, the in vitro-synthesized chimeras showed no editing of downstream editing sites. The synthesis of chimeric RNAs required ATP and was dependent on the formation of a gRNA/mRNA anchor duplex 3' of the pre-edited region, as shown by in vitro mutagenesis of the mRNA and the gRNA. mRNA sequences 3' and 5' of the pre-edited region also affected the efficiency of the chimera-forming activity. This in vitro system may accurately represent the initial step in RNA editing.

Patient protocols

Details the introduction by Northallerton Health Services NHS Trust of critical paths and care profiles as tools within its Co‐ordinated Care Programme. Aims to use these tools as means to assess and improve on the care which patients receive, and to monitor clinical performance. Identifies the development of protocols of care as one vehicle through which care can be monitored. Discusses the progression of the programme and how its scope continues to extend with a view to incorporating primary care right down to general practitioner level.

Rotational angioplasty and directional atherectomy to treat complex lesions of the right coronary artery

A combination of interventional devices including the Rotablator and directional coronary atherectomy (DCA) was used to treat a 39-year-old patient with a complex lesion of the right coronary artery. The devices enabled the recanalization and reconstruction of the diseased vessel without laceration or dissection, leaving a smooth-edged segment. The histological analysis of the tissue obtained from DCA revealed no predictors of restenosis, like highly cellular material or media. Thus, combination of mechanical interventional devices allowed to treat a highly complex lesion without lacerating the vessel and leaving an excellent acute and long-term outcome.

Countertransference and clinical choices in public-sector treatment of a patient and her family

Clinical decision making in the treatment of families of individuals with prolonged mental illness can be affected by countertransference that is stimulated by the context of treatment as well as by the family being treated. For clinicians, psychoeducation, the current intervention of choice for such families, can serve defensive functions that are motivated by counter-transference; a case example illustrates how such defenses led a clinician to avoid deeper therapeutic work. The authors believe that clinicians must strive to understand their motivations for whatever clinical decisions they make; to facilitate this awareness, intensive psychotherapy should be required as an adjunct to training.

Generation of unexpected editing patterns in Leishmania tarentolae mitochondrial mRNAs: misediting produced by misguiding

We have analyzed the generation of unexpected patterns of RNA editing, i.e., those not following a strict 3' to 5' progression, which occur in junction regions between fully edited and preedited sequences. Evidence is presented that these patterns are generated by misediting due to specific events of misguiding. Misediting can occur through the interaction of inappropriate gRNAs with mRNAs or appropriate gRNAs in an incorrect fashion. Four possible mechanisms for the generation of misedited sequences are presented. Chimeric molecules have been detected in steady-state mitochondrial RNAs that are composed of misguiding gRNAs covalently linked to mRNAs at misediting sites by the 3' oligo(U) tail. We propose that misediting within junction regions can be corrected by appropriately acting gRNAs.

The polarity of editing within a multiple gRNA-mediated domain is due to formation of anchors for upstream gRNAs by downstream editing

Seventeen kinetoplast minicircle-encoded and nine maxicircle-encoded gRNA genes have been identified. Six overlapping minicircle-encoded gRNAs mediate editing for the 5'-pan-edited MURF4 gene and two for the 5'-edited COIII gene. The pan-edited RPS12 mRNA is edited by seven minicircle-encoded gRNAs and one maxicircle-encoded gRNA. The 3'-most gRNA in each domain forms an anchor with unedited mRNA, whereas upstream gRNAs form anchors only with edited mRNA, thereby explaining the observed 3' to 5' polarity of editing within an editing domain. We suggest that a role of G-U base pairs is to allow breathing of the edited mRNA-gRNA hybrid and formation of the upstream anchor hybrid.

Efficacy of directional coronary atherectomy in cases unsuitable for percutaneous transluminal coronary angioplasty (PTCA) and after unsuccessful PTCA

Directional coronary atherectomy (DCA) was used in 10 female and 50 male patients with an average age of 58 years. They were categorized into three different groups depending on the indications for atherectomy. Group 1 included all patients who had atherectomy as their primary intervention (n = 20) because they were assumed to be unsuitable for percutaneous transluminal coronary angioplasty (PTCA). Group 2 consisted of patients in whom DCA was used after failed balloon dilatation with unsuccessful but uneventful treatment (n = 17). Group 3 (n = 23) included patients in whom DCA was performed as a "rescue" or "bailout" procedure after unsuccessful PTCA resulting in critical ischemia (ECG changes, chest pain, hypotension, and shock). The target lesions were located in the left main artery in two, left anterior descending artery in 43, right coronary artery in 15, and aortocoronary venous bypass in five. The mean length of the lesions was 8 mm (2 to 25 mm). The overall success rate for 65 lesions was 92%. The mean stenosis was reduced from 87 +/- 12% to 19 +/- 17% in patients with primary success. Presently available follow-up angiograms (30) showed six restenoses. Major complications occurred in seven patients (myocardial infarction in two and coronary artery bypass graft surgery within 24 hours in five); there were no deaths. Our results show that DCA is a safe and effective technique that can extend the use of percutaneous procedures and provide a promising nonsurgical option in cases of unsuccessful PTCA.

Computer methods for locating kinetoplastid cryptogenes

RNA editing in the mitochondria of kinetoplastid protoza involves the insertion and/or deletion of precise numbers of uridine residues at precise locations in the numbers of uridine residues at precise locations in the transcribed RNA of certain genes. These genes are known as cryptogenes. In this paper we study computational algorithms to search for unknown cryptogenes and for the associated templates for insertion of uridines, gRNA sequences. The pairwise similarity search algorithm of Smith and Waterman (1) is modified to study this problem. The algorithm searches for unknown gRNAs given the cryptogene sequence. The method is tested on 4 known cryptogenes from L.tarentolae which are known to have 7 associated gRNAs. The statistical distribution of the longest gRNA when comparing random sequences is derived. Finally we develop an algorithm to search for cryptogenes using amino acid sequences from related proteins.

Should we palpate foot pulses?

Palpation of foot pulses is traditionally used to evaluate patients with arterial disease. This study investigated observer variation in assessment of pedal vessels by pulse palpation and Doppler auscultation. A series of 33 claudicant patients and five controls were examined by a consultant, registrar, SHO and nurse. Dorsalis pedis (DP) and posterior tibial (PT) pulses were palpated and were then examined by Doppler with measurement of systolic pressures.

CONTROL GROUP

No disagreement in DP pulses. However, all observers agreed on the presence of a PT pulse in only 70% of limbs. Claudicants: There was better agreement in palpation of the DP pulse (all observers agreed in 67% of limbs), than the PT pulse (all agreed in 53%). This suggests that the DP pulse is easier to palpate than the PT (P less than 0.05). By contrast there was better agreement on Doppler signals from the PT artery, all agreed in 78% of limbs; compared with the DP artery, all agreed in 58% (P less than 0.01). Pressure measurements by the observers agreed to within +/- 0.15 in 88% of claudicant and 100% of control limbs. Pedal pulse palpation in patients with arterial disease is subject to substantial observer error. Doppler pressure measurement is preferable unless pulses are bounding.

A ribonuclease activity is activated by heparin or by digestion with proteinase K in mitochondrial extracts of Leishmania tarentolae

A ribonuclease activity in a 100,000 x g supernatant of a Triton lysate of a mitochondrial-kinetoplast fraction from Leishmania tarentolae is activated by incubation with heparin or by predigestion of the lysate with proteinase k or pronase. In vitro-transcribed pre-edited cytochrome b mRNA is cleaved at several sites. With time, complete degradation of the RNA occurs. All cleavages occurred within putative single-stranded regions of the RNA. No cleavage was observed with 9 S rRNA. The presence of a nonspecific nucleotide or nucleoside slows the rate of cleavage. The cleavage activity is inhibited by sodium dodecyl sulfate or phenol/chloroform extraction, is retained by a 10-kDa cutoff filter, and passes through a 30-kDa filter. Micrococcal nuclease inhibits the proteinase-induced activity but not the heparin-induced activity.

Hypertension in insulin-resistant Zucker obese rats is independent of sympathetic neural support

We have previously reported that insulin-resistant Zucker obese rats exhibit hypertension associated with impaired vascular smooth muscle (VSM) Ca2+ transport and proposed that this results from failure of insulin to regulate VSM Ca2+ transport in insulin resistance. However, hypertension in insulin-resistant states is generally attributed to hyperinsulinemia, with a consequent stimulation of sympathetic neural activity. Accordingly, the present study was conducted to determine whether the hypertension observed in Zucker obese rats compared with their lean controls was dependent on either increased sympathetic neural activity or exaggerated vascular reactivity. Intra-arterial blood pressure responses to ganglionic blockade with Ecolid (chlorisondamine chloride) and to graded intravenous injections of angiotensin II and norepinephrine were compared in 6- to 8-wk-old male Zucker rats and their lean controls (n = 10/group). The obese rats exhibited significant hypertension before ganglionic blockade (P less than 0.001), and this difference was largely sustained during ganglionic blockade (P less than 0.005). Furthermore, the obese rats exhibited greater pressor sensitivity to both angiotensin II and to norepinephrine during ganglionic blockade (P less than 0.01). Thus enhanced pressor sensitivity, independent of sympathetic neural activity, appears to support hypertension in Zucker obese rats.

An intergenic G-rich region in Leishmania tarentolae kinetoplast maxicircle DNA is a pan-edited cryptogene encoding ribosomal protein S12

Six short G-rich intergenic regions in the maxicircle of Leishmania tarentolae are conserved in location and polarity in two other kinetoplastid species. We show here that G-rich region 6 (G6) represents a pan-edited cryptogene which contains at least two domains edited independently in a 3'-to-5' manner connected by short unedited regions. In the completely edited RNA, 117 uridines are added at 49 sites and 32 uridines are deleted at 13 sites, creating a translated 85-amino-acid polypeptide. Similar polypeptides are probably encoded by pan-edited G6 transcripts in two other species. The G6 polypeptide has significant sequence similarity to the family of S12 ribosomal proteins. A minicircle-encoded gRNA overlaps 12 editing sites in G6 mRNA, and chimeric gRNA/mRNA molecules were shown to exist, in agreement with the transesterification model for editing.

Recurrent polymorphisms in small chromosomes of Leishmania tarentolae after nutrient stress or subcloning

Molecular karyotypes of the UC, LEM87 and LEM115 Leishmania tarentolae strains were obtained. All strains had 24-28 chromosomal bands which varied in size between 300 kb and 2.9 Mb. Several recurrent chromosomal polymorphisms occurred in LEM115 after nutrient shock or subcloning. One type of polymorphism involves the truncation of a 365-kb chromosome which contains the miniexon genes. This specific chromosome breakage appears to be induced by the nutrient shock or subcloning process and also occurs spontaneously during routine passage. Another polymorphism is the appearance of a 90-kb minichromosome (115-SNA1) after severe nutrient shock. This appears to be selection of a pre-existing cell type from a mosaic population. The 115-SNA1 minichromosome has sequence homology with a minichromosome in LEM87 cells but shows no homology with any chromosomes in 115wt or other strains. The copy number of 115-SNA1 varies with culture conditions, suggesting a relaxed centromeric control. The nature and origin of this minichromosome is not known.

Leishmania tarentolae minicircles of different sequence classes encode single guide RNAs located in the variable region approximately 150 bp from the conserved region

The complete sequences of three kinetoplast DNA minicircles (B4, D3 and D12) from Leishmania tarentolae are reported. All L. tarentolae minicircles encode single gRNAs localized within the variable region approximately 150 bp from the conserved region. The 5' termini and tentative 3' termini of the new gRNAs were determined and the gene sequences and flanking sequences of all minicircle gRNA genes compared for conserved motifs of possible transcriptional regulatory significance. All minicircle gRNAs possess 3' oligo-[U] tails of variable length similar to maxicircle gRNAs. A role for the D3 minicircle gRNA in the editing of the 5' pan-edited MURF4 mRNA was suggested by sequence analysis, and a role for the D12 minicircle gRNA in the editing of the COIII mRNA and another minicircle gRNA (Lt154) in the editing of the pan-edited G6 mRNA have been previously reported. The cryptogene mRNAs edited by the B4 and Lt19 minicircle gRNAs are yet undetermined.

Polymerase chain reaction amplification of Trypanosoma cruzi kinetoplast minicircle DNA isolated from whole blood lysates: diagnosis of chronic Chagas' disease

A 6 M guanidine-HCl/0.2 M EDTA solution was used to lyse and store whole blood specimens. DNA stored in guanidine-EDTA-blood (GEB) lysate was found to be undegraded after incubation at 37 degrees C for 1 month, suggesting that this represents an appropriate reagent for transport of blood samples from the field to a laboratory for analysis. Trypanosoma cruzi kinetoplast DNA in GEB lysate can be cleaved using the chemical nuclease, 1,10-phenanthroline-copper ion (OP-Cu2+). This procedure liberates linearized minicircle molecules from network catenation, distributing them throughout the lysate, and allowing a small aliquot of the original lysate to be analyzed by PCR amplification. This increases the sensitivity of the method dramatically for the detection of small numbers of trypanosomes in a large volume of blood. DNAs isolated from aliquots of T. cruzi-positive GEB lysates were polymerase chain reaction (PCR)-amplified with 3 sets of T. cruzi-specific kDNA minicircle primers, yielding the 83-bp and 122-bp conserved region fragments and the 330-bp variable region fragments. The PCR products were analyzed by gel electrophoresis and/or hybridization. Results indicate that a single T. cruzi cell in 20 ml of blood can be detected by this method. Blood samples from several chronic chagasic patients were tested. Amplification of T. cruzi kDNA minicircle sequences was obtained in al cases, even when xenodiagnosis was negative. This PCR-based test should prove useful as a replacement or complement for xenodiagnosis or serology in clinical and epidemiological studies of chronic Chagas' disease.

Biomechanical testing of new and old fixation devices for vertical shear fractures of the pelvis

Malgaigne fractures of the pelvis have been treated with many different methods of fixation. We developed a plate for use on the anterior aspect of the sacroiliac (SI) joint using information obtained from cadaveric dissections and computed tomography (CT) scans of male (50) and female (50) pelvises. We tested each of six pelvises in the Instron, with five different fixation systems. Our results showed that the weakest system was the anterior quadrilateral frame plus two symphyseal plates. When comparing three posterior screws with the SI joint plate, the difference was not statistically significant. However, in both of these systems, a second symphyseal plate added to the overall stability.

Chimeric gRNA-mRNA molecules with oligo(U) tails covalently linked at sites of RNA editing suggest that U addition occurs by transesterification

Chimeric RNA molecules were detected by polymerase chain reaction amplification of kinetoplast RNA using a 3' primer specific to mRNA and a 5' primer specific to guide RNA (gRNA), and directly by Northern analysis. Covalent linkage of the 3' oligo(U) tail of the gRNA to the mRNA occurs at editing sites. Chimeric molecules were isolated for NADH dehydrogenase subunit 7 and cytochrome oxidase subunits II and III. We propose that these molecules are intermediates in the editing process and that successive transesterifications result in the transfer of uridine residues from the gRNA 3' oligo(U) tail to an editing site, with the number of uridine residues determined by base pairing with adenine and guanine "guide" nucleotides in the gRNA.