scAbsolute: measuring single-cell ploidy and replication status

Cancer cells often exhibit DNA copy number aberrations and can vary widely in their ploidy. Correct estimation of the ploidy of single-cell genomes is paramount for downstream analysis. Based only on single-cell DNA sequencing information, scAbsolute achieves accurate and unbiased measurement of single-cell ploidy and replication status, including whole-genome duplications. We demonstrate scAbsolute's capabilities using experimental cell multiplets, a FUCCI cell cycle expression system, and a benchmark against state-of-the-art methods. scAbsolute provides a robust foundation for single-cell DNA sequencing analysis across different technologies and has the potential to enable improvements in a number of downstream analyses.

High-grade serous ovarian carcinoma organoids as models of chromosomal instability

High-grade serous ovarian carcinoma (HGSOC) is the most genomically complex cancer, characterized by ubiquitous TP53 mutation, profound chromosomal instability, and heterogeneity. The mutational processes driving chromosomal instability in HGSOC can be distinguished by specific copy number signatures. To develop clinically relevant models of these mutational processes we derived 15 continuous HGSOC patient-derived organoids (PDOs) and characterized them using bulk transcriptomic, bulk genomic, single-cell genomic, and drug sensitivity assays. We show that HGSOC PDOs comprise communities of different clonal populations and represent models of different causes of chromosomal instability including homologous recombination deficiency, chromothripsis, tandem-duplicator phenotype, and whole genome duplication. We also show that these PDOs can be used as exploratory tools to study transcriptional effects of copy number alterations as well as compound-sensitivity tests. In summary, HGSOC PDO cultures provide validated genomic models for studies of specific mutational processes and precision therapeutics.

SGLT-2-inhibition with dapagliflozin reduces tissue sodium content: a randomised controlled trial

Background and aims

Sodium tissue content by ²³Na magnetic resonance imaging (Na-MRI) has been validated in experimental and human studies. SGLT-2 inhibition blocks the reabsorption of glucose and of sodium in the proximal tubular cells in a 1:1 fashion. We hypothesized that SGLT-2 inhibition in patients with type 2 diabetes characterized by sodium retention leads to decreased tissue sodium content due to its pharmacological action.

Materials and methods

In a prospective double blind, placebo controlled, cross-over trial 59 patients (61 ± 7.6 years) with type 2 diabetes were randomized to either dapagliflozin 10 mg or placebo once daily for 6 weeks each. In addition to metabolic parameters and ambulatory blood pressure (BP) we analysed the sodium content in the skin and muscles of the lower leg by Na-MRI.

Results

Compared to baseline 6 weeks treatment with the SGLT-2 inhibitor dapagliflozin decreased fasting (132 ± 28 vs. 114 ± 19 mg/dl, p < 0.001), postprandial blood glucose (178 ± 66 mg/dl vs. 153 ± 46 mg/dl, p < 0.001), body weight (87.6 vs. 86.6 kg, p < 0.001) and systolic (129 ± 12 vs. 126 ± 11 mmHg, p = 0.010), and diastolic (77.4 ± 9 vs. 75.6 ± 8 mmHg, p = 0.024), 24-h ambulatory BP. Tissue sodium content in the skin was reduced after 6 weeks treatment with dapagliflozin compared to baseline [24.1 ± 6.6 vs. 22.7 ± 6.4 A.U.(arbitrary unit) p = 0.013]. No significant reduction of tissue sodium content was observed in the muscle (M. triceps surae: 20.5 ± 3.5 vs. 20.4 ± 3.7 A.U. p = 0.801). No clear significant difference in tissue water content of muscle and skin was observed after 6 weeks of treatment with dapagliflozin, compared to baseline.

Conclusion

SGLT-2 inhibition with dapagliflozin resulted in a significant decrease in tissue sodium content of the skin after 6 weeks. This observation point to a decrease of total sodium content in patients with type 2 diabetes prone to cardiovascular complications, that might be mitigated by SGLT-2 inhibition.

Trial registration The study was registered at http://www.clinicaltrials.gov (NCT02383238) retrospectively registered

HIV-infected patients' beliefs about their chronic co-treatments in comparison with their combined antiretroviral therapy

Objectives

Thanks to the success of combination antiretroviral therapy (cART), HIV‐infected patients can have almost a normal life expectancy. This has resulted in an aging HIV‐infected population with other chronic comorbidities such as cardiovascular diseases, osteoporosis, and depression. Our hypothesis is that patients' perceptions of and attitudes towards their cART, which is perceived as crucial to their survival, differ from their beliefs about their co‐treatments, and this may have an impact on their medication adherence.

Methods

We used the French version of the Beliefs about Medicine Questionnaire (BMQ‐f) to measure the perceptions of patients about their co‐treatments and the Beliefs about Medicine Questionnaire for Highly Active Antiretroviral Therapy (BMQ‐HAART) to measure their beliefs about their cART in a representative sample (n = 150) of patients enrolled in the Swiss HIV Cohort Study (SHCS) and followed at the Infectious Disease Service at the University Hospital in Lausanne, Switzerland. The survey was administered to all eligible patients by the order of their scheduled appointments at the end of their medical visit. The BMQ comprises two subscores: Specific‐Necessity (5 identical items in BMQ‐f and BMQ‐HAART) and Specific‐Concerns (also 5 identical items in BMQ‐f and BMQ‐HAART). The subscores were standardized by dividing the score scale by the number of questions in the scale, resulting in a range of responses between 1 (low) and 5 (high). Self‐reported medication adherence was measured using the SHCS Adherence Questionnaire (SHCS‐AQ). Adherence was defined as not missing any dose or missing one dose of the treatment in the past 4 weeks. Sociodemographic variables were retrieved by reviewing the SHCS database.

Results

A response rate of 73% (109 of 150) was achieved. A total of 105 patients were included in the analysis: their median age was 56 [interquartile range (IQR) 51, 63] years and 74 were male (70%). Eighty‐seven patients (83%) were adherent to cART and 75 (71%) were adherent to their co‐treatments (P = 0.0001). The standardized mean responses for the BMQ Specific‐Necessity subscores were 4.46 [standard deviation (SD): 0.58] and 2.86 (SD: 1.02) for cART and co‐treatments, respectively (P < 0.0001). For Specific‐Concerns, the standardized mean responses were 2.9 (SD: 1.02) for cART and 4.09 (SD: 1.02) (P < 0.0001) for co‐treatments. cART and co‐treatment concerns increased as the number of co‐treatments increased (P = 0.03 and P < 0.0001, respectively).

Conclusions

Patients had higher Necessity and lower Concerns scores for their cART in comparison with their co‐treatments. A higher percentage of patients reported being adherent to cART compared with the co‐treatments that they reported they were most likely to miss. Further research using a bigger sample size and more objective measures of adherence is needed to explore the association between adherence and patients' perceptions.

Switching from a two-tablet regimen of tenofovir/emtricitabine and efavirenz to a one-tablet regimen may affect patients' perceptions and drug management

OBJECTIVES

Simplification of antiretroviral therapy enhances a patient's adherence but a new formulation could also lead to new adverse events and changes in daily routine. This study compared medication adherence, tolerance and satisfaction among subjects switching from a two-tablet tenofovir/emtricitabine/efavirenz regimen to a one-tablet regimen.

METHODS

Clinical and sociodemographic data were collected and three surveys were administered at month 0 (=switch), and then 1 and 4-6 months after the switch: the Beliefs about Medicines Questionnaire, the HIV-symptom index questionnaire, the Short HIV Treatment Satisfaction Questionnaire, the Swiss HIV Cohort Study (SHCS) two-item adherence questionnaire, and a questionnaire on daily combination antiretroviral therapy (cART) management. Medication adherence of a subgroup of subjects was routinely monitored using an electronic device (MEMS(™) ).

RESULTS

Eighty-eight subjects gave informed consent to participate in the study. The subjects' back-switch rate was 7% (six of 88). Subjects who did not back-switch preferred the one-tablet regimen (median = 2; IQR = 1.3-2.5; on a -3 to 3 scale), but no change in adherence was found (10 of 46 nonadherent subjects; P = 1.00). The perception of treatment necessity score decreased (P = 0.004), the efavirenz blood level increased (14%; P = 0.04), and association/dissociation of cART with food intake evolved (P = 0.01) after the switch. Subjects listed equivalent numbers of symptoms during the three visits.

CONCLUSIONS

The one-tablet regimen was preferred but the number of back-switches was not negligible. The perception of treatment necessity score decreased with the simplification of the regimen from a two-tablet to a one-tablet formulation, which could negatively impact adherence. Switching is a sensitive time in a patient's treatment life and professionals should pay particular attention to patient's perceptions of treatment during such a transition.

Photoelectron spin-polarization control in the topological insulator Bi2Se3

We study the manipulation of the spin polarization of photoemitted electrons in Bi2Se3 by spin- and angle-resolved photoemission spectroscopy. General rules are established that enable controlling the photoelectron spin-polarization. We demonstrate the ± 100% reversal of a single component of the measured spin-polarization vector upon the rotation of light polarization, as well as full three-dimensional manipulation by varying experimental configuration and photon energy. While a material-specific density-functional theory analysis is needed for the quantitative description, a minimal yet fully generalized two-atomic-layer model qualitatively accounts for the spin response based on the interplay of optical selection rules, photoelectron interference, and topological surface-state complex structure. It follows that photoelectron spin-polarization control is generically achievable in systems with a layer-dependent, entangled spin-orbital texture.

[Therapeutic adherence to oral cancer therapy and interdisciplinary management]

Medication adherence is a well-known risk factor in internal medicine. However in oncology this dimension is emerging due to the increasing number of oral formulations. First results in the oral oncology literature suggest that patients' ability to cope with medical prescription decreases with time. This might preclude patients from reaching clinical outcomes. Factors impacting on medication adherence to oral oncology treatments have not been yet extensively described neither strategies to address them and support patient's needs. Oncologists and pharmacists in our University outpatient settings performed a pilot study which aimed at measuring and facilitating adherence to oral oncology treatments and at understanding determinants of patient's adherence. The ultimate purpose of such a patient-centered and interdisciplinary collaboration would be to promote patient self-management and complement the standard medical follow-up.

[More HIV-positive women are referred to a medication adherence clinic than men]

HIV-positive patients with antiretroviral medication adherence issues are referred to an outpatient adherence clinic. Surprisingly, two-third of referred patients are women although more than 60% of the patients at the Infectious Disease Outpatient service are men. Women seem to be referred because of specific social factors: children at home, black sub-Saharan ethnicity, difficulties in medication and disease management due to stigmatization. Literature is poor and controversial and it is not possible to conclude whether medication adherence varies with gender. However, recent data seem to show that reasons for nonadherence vary according to gender.

Esterase D in Cebus apella from the Amazonian region

Research programs involving the study of genetic variation of proteins have been carried out both in humans and catarrhine primates but rarely in New World species. Considering the great possibilities offered by protein variations as genetic markers in systematic and evolutionary studies in this group of organisms, the authors are specially interested in the investigation of genetic polymorphisms of blood proteins in Amazonian primates. In this paper we describe the electrophoretic patterns of erythrocyte esterases obtained from blood samples of 57 Cebus apella specimens. Blood hemolysates from Cebus display four main set of bands in azo-coupled stained gels. These bands are identified as esterases P, A1, A2 and B by their electrophoretic migration, substrate specificity and eserine reaction. The use of the fluorogenic reagent 4-methylumbelliferyl acetate revealed the presence of a fifth set of enzymes not detected by the azo-coupled staining method. This set of enzymes, probably a polymorphic genetic system, was named ESD as in humans.

The effect of statins on angiotensin II-induced hemodynamic changes in young, mildly hypercholesterolemic men

BACKGROUND

Angiotensin II type 1 (AT(1)) receptors are well known to mediate angiotensin II (Ang II)-induced pro-atherosclerotic effects. It has been found that hypercholesterolemia influences the expression of AT(1) receptors on vascular smooth muscle cells and that increased density of AT(1) receptors exaggerates the hemodynamic response to Ang II. We analyzed to what extent statins and AT(1) receptor antagonists diminish the vasoconstrictive response to Ang II infusion in hypercholesterolemic patients.

METHODS

A total of 24 male patients with LDL cholesterol levels >130 mg/dL were enrolled in a randomized, cross-over study. After baseline evaluation, 12 patients received first cerivastatin (0.3 mg/day) and the other 12 patients initially received candesartan (8 mg/day) for 3 weeks, with subsequent cross-over of the medication for the second 3-week drug period. The vascular response was analyzed by the increase in mean arterial pressure (MAP) and total peripheral resistance (TPR) during infusion of increasing doses of Ang II at baseline and the end of each treatment period. Hemodynamic changes were also compared with those in 24 normocholesterolemic subjects without any therapy.

RESULTS

At baseline, Ang II provoked a similar increase of MAP and TPR in patients and control subjects. Treatment with cerivastatin did not affect the response to Ang II compared with baseline. By contrast, treatment with candesartan attenuated significantly the response to Ang II compared with baseline and cerivastatin.

CONCLUSIONS

Our hemodynamic data indicate the hypothesis that statins do not reduce the responsiveness to Ang II in resistance arteries of young, mildly hypercholesterolemic patients.

HELLP syndrome in the 18th week of gestation in association with elevated angiotensin AT(1)-receptor autoantibodies

We present a 24-year-old woman with a twin pregnancy who was with a typical HELLP syndrome at the 18th week of pregnancy. One fetus was dead, while the other was severely growth retarded. Our patient had agonistic autoantibodies directed at the angiotensin AT(1)-receptor. Termination of the pregnancy proved necessary. This report is the first to our knowledge associating HELLP syndrome with angiotensin AT(1)-receptor antibodies. Since the antibodies may have a pathogenic significance, their removal could permit the prolongation of pregnancy in preeclamptic and HELLP syndrome patients.

Impaired sodium excretion during mental stress in mild essential hypertension

In hypertensive rats, environmental stress causes sodium retention by an exaggerated increase in renal sympathetic nerve activity, which is modulated by angiotensin II. We tested whether similar effects can be observed in humans. In 66 normotensive subjects (half of them with a family history of hypertension) and 36 subjects with mild essential hypertension, urinary sodium excretion and renal hemodynamics were examined at rest and during mental stress treated either with placebo or ACE inhibition in a double-blind, randomized, cross-over design. Despite a marked increase in glomerular filtration rate in response to mental stress (Deltaglomerular filtration rate, 4.3+/-7.7 mL/min in normotensives without versus 5.6+/-8.4 mL/min in normotensives with a family history versus 10.1+/-5.7 mL/min in patients with mild essential hypertension; P:<0.002), the increase in urinary sodium excretion was blunted in patients with mild essential hypertension (Deltaurinary sodium excretion, 0.12+/-0.17 mmol/min versus 0.10+/-0.14 mmol/min versus 0.05+/-0.14 mmol/min; P:<0.05). ACE inhibition corrected the natriuretic response to mental stress in subjects with mild essential hypertension (Deltaurinary sodium excretion, 0.05+/-0.14 mmol/min with placebo versus 0.13+/-0.19 mmol/min with ACE inhibition; P:<0.01); thus, after ACE inhibition, urinary sodium excretion increased similarly in all 3 groups. In conclusion, impaired sodium excretion occurs during mental stress in human essential hypertension but not in subjects with positive family history of hypertension. This abnormality in sodium handling during activation of the sympathetic nervous system appears to be mediated by angiotensin II.

Electronic compliance monitoring in resistant hypertension: the basis for rational therapeutic decisions

OBJECTIVE

Incomplete compliance is one of several possible causes of uncontrolled hypertension. Yet, non-compliance remains largely unrecognized and is falsely interpreted as treatment resistance, because it is difficult to confirm or exclude objectively. The goal of this study was to evaluate the potential benefits of electronic monitoring of drug compliance in the management of patients with resistant hypertension.

METHODS

Forty-one hypertensive patients resistant to a three-drug regimen (average blood pressure 156/ 106 +/- 23/11 mmHg, mean +/- SD) were studied prospectively. They were informed that for the next 2 months, their presently prescribed drugs would be provided in electronic monitors, without any change in treatment, so as to provide the treating physician with a measure of their compliance. Thereafter, patients were offered the possibility of prolonging the monitoring of compliance for another 2 month period, during which treatment was adapted if necessary.

RESULTS

Monitoring of compliance alone was associated with a significant improvement of blood pressure at 2 months (145/97 +/- 20/15 mmHg, P < 0.01). During monitoring, blood pressure was normalized (systolic < 140 mmHg or diastolic < 90 mmHg) in one-third of the patients and insufficient compliance was unmasked in another 20%. When analysed according to tertiles of compliance, patients with the lowest compliance exhibited significantly higher achieved diastolic blood pressures (P = 0.04). In 30 patients, compliance was monitored up to 4 months and drug therapy was adapted whenever necessary. In these patients, a further significant decrease in blood pressure was obtained (from 150/100 +/- 18/15 to 143/94 +/- 22/11 mmHg, P = 0.04/0.02).

CONCLUSIONS

These results suggest that objective monitoring of compliance using electronic devices may be a useful step in the management of patients with refractory hypertension, as it enables physicians to take rational decisions based on reliable and objective data of drug compliance and hence to improve blood pressure control.

Vascular reactivity in patients with preeclampsia and HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome

OBJECTIVE

Early structural and functional changes in the systemic vasculature have been proposed to play a major pathogenetic role in preeclampsia and HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome. The aim of the study was to determine vascular reactivity in patients with preeclampsia with and without HELLP syndrome with respect to those in healthy pregnant control subjects.

STUDY DESIGN

Forearm blood flow was measured by strain gauge plethysmography with the venous occlusion technique in 12 hypertensive patients with HELLP syndrome, in 8 patients with preeclampsia without HELLP syndrome, and in 8 healthy normotensive pregnant control subjects. To determine vascular reactivity the forearm blood flow was measured at baseline and after forearm occlusion for a period of 5 minutes (reactive hyperemia). The investigations were repeated 4 to 6 months post partum. Forearm vascular resistance was calculated as the ratio of mean arterial pressure to forearm blood flow.

RESULTS

Mean arterial pressure at rest was elevated in patients with preeclampsia (116 +/- 20 mm Hg) and in patients with HELLP syndrome (110 +/- 16 mm Hg) with respect to healthy pregnant control subjects (86 +/- 10 mm Hg; P <.05). Forearm blood flow at rest was not statistically different in patients with preeclampsia (5.1 +/- 2.6 mL/min per 100 mL) and with HELLP syndrome (4.7 +/- 1.5 mL/min per 100 mL) with respect to pregnant control subjects (5.9 +/- 3.1 mL/min per 100 mL); however, forearm vascular resistance at rest was elevated in patients with preeclampsia (25.9 +/- 9.5 units; P <.05) and in patients with HELLP syndrome(24.6 +/- 6.9 units; P <.05) with respect to healthy control subjects (17.0 +/- 6.1 units). During reactive hyperemia the peak forearm blood flow, which is an indicator of maximal vasodilatory capacity, was impaired in patients with preeclampsia (21.9 +/- 8.2 mL/min per 100 mL; P <.05) but not in patients with HELLP syndrome (37.4 +/- 17.5 mL/min per 100 mL) and healthy control subjects (44.9 +/- 15.0 mL/min per 100 mL). Consequently, minimum forearm vascular resistance was higher in women with preeclampsia (6.1 +/- 1.9 units) than in both women with HELLP syndrome (3.5 +/- 1.6 units) and the control subjects (2.8 +/- 2.4 units).

CONCLUSION

Despite similarly elevated forearm vascular resistances at rest in patients with HELLP syndrome and in patients with preeclampsia, forearm vascular resistance during reactive hyperemia did not differ significantly from that in healthy control subjects in the women with HELLP syndrome but was increased in women with preeclampsia. Vasodilatory reactivity thus is reduced in preeclampsia but not in HELLP syndrome, which suggests different alterations of the vasculature.

Functional gene testing of the Glu298Asp polymorphism of the endothelial NO synthase

OBJECTIVES

To test whether the Glu298Asp polymorphism of the endothelial nitric oxide synthase (eNOS) gene is of functional relevance in humans by altering endothelium-dependent vasodilation.

BACKGROUND

The Asp298 variant of the eNOS gene product has been associated with arterial hypertension, coronary artery disease and myocardial infarction. The pathogenetic mechanism has not yet been elucidated. Since endothelium-dependent vasodilation has been shown to be impaired in these disorders, we hypothesized that the Glu298Asp polymorphism of the eNOS gene influences endothelium-dependent vasodilation.

METHODS

In 80 patients with normal or elevated cholesterol, endothelium-dependent and -independent vasodilation was assessed. Forearm blood flow was measured by plethysmography in response to intra-arterial (i.a.) infusion of 12 and 48 microg/min acetylcholine and 3.2 and 12.8 microg/min nitroprusside, respectively. NG-monomethyl-L-arginine (L-NMMA) in doses of 4, 8 and 16 micromol/min was infused to test basal nitric oxide (NO) production and release. Genomic DNA was extracted from blood samples to determine the Glu298Asp polymorphism of the eNOS gene at position 1917 G/T after BanII restriction.

RESULTS

Baseline parameters (age, gender, blood pressure, body mass index, cholesterol level) were similar across the genotypes. Genotype frequencies did not deviate from the Hardy-Weinberg equilibrium. No differences in forearm blood flow to i.a. acetylcholine (average increase: + 554 +/- 371%), nitroprusside or L-NMMA infusion were found across the eNOS genotypes, neither for endothelium-dependent or endothelium-independent vasodilation, nor for basal NO production and release. Our sample size of n = 80 had a power of > 80% (beta = 0.20) with a P value < 0.05 (alpha = 0.05) to detect a 200% difference in forearm blood flow response to 48 microg/min acetylcholine.

CONCLUSIONS

At a power of 80%, we can exclude a relevant effect on endothelium-dependent vasodilation due to the eNOS Glu298Asp polymorphism. Thus, our functional genetic study does not suggest any biological effect of the eNOS Glu298Asp genotype on the cardiovascular system via an influence on endothelium-dependent vasodilation.

Sequences from the 5' flanking region of the epsilon-globin gene support the relationship of Callicebus with the pitheciins

The purpose of this study was to determine nucleotide sequences from the 5' flanking region of the epsilon-globin gene of selected platyrrhine primates and to analyze the data for phylogenetic information and estimated times of divergence. We report new sequence data for two species of New World monkeys, Callicebus torquatus and Pithecia irrorata. We analyzed these data in conjunction with homologous sequences from other primate species. The data support the hypothesis that the titi monkeys (Callicebus) and seed predators (Tribe Pitheciini) form a clade (Subfamily Pitheciinae), and also provide limited support for that subfamily being allied with the atelines. We also present estimated dates of divergence for the Callicebus and pitheciin lineages.

New Syntheses with Oils and Fats as Renewable Raw Materials for the Chemical Industry

Oils and fats are the most important renewable raw materials for the chemical industry. Hitherto, industrial oleochemistry has concentrated predominantly on the carboxy functionality of fatty acids but, more recently, modern synthetic methods have been applied extensively to fatty compounds for the selective functionalization of the alkyl chain. Radical, electrophilic, nucleophilic, and pericyclic as well as transition metal catalyzed additions to the C-C double bond of, for example, oleic acid as the prototype of a readily accessible, unsaturated fatty acid have led to a large number of novel fatty compounds from which interesting properties are expected. Functionalization of C-H bonds in the alkyl chain is also feasible with remarkable selectivity. Effective and highly versatile catalysts for the metathesis of esters of unsaturated fatty acids have been developed, which lead to new and interesting omega-unsaturated fatty acids. The epoxidation of unsaturated fatty acids has been developed extensively. Enzymatic reactions allow syntheses with high selectivity and yield of mono- and diglycerides and esters of carbohydrates with a variety of surfactant properties. Regio- and enantioselective microbial hydrations and hydroxylations widen the spectrum of selective reactions. Of considerable significance is that, with the use of gene technology, natural oils and fats have been improved significantly and will be improved still further, insofar as they show a more uniform and often unusual fatty acid spectrum. Numerous fatty acids are now available in a purity which makes them attractive for synthesis and as raw materials for the chemical industry.

Computer simulations of enantioselective ester hydrolyses catalyzed by Pseudomonas cepacia lipase

On the basis of the X-ray crystal structure of the lipase from Pseudomonas cepacia (PcL)-an enzyme representative for a whole family of Pseudomonas lipases (lipase PS, SAM-2, AK 10, and others with a high degree of homology with PcL)-a computational study was performed to rationalize both the enantioselectivity and substrate specificity (tolerance) displayed by this lipase in the enantioselective hydrolysis of racemic esters 1a-12a from various secondary aromatic alcohols. The major goal of this project was the development of a binding model for PcL which is able to rationalize the experimental findings to predict "a priori the enantioselective behavior of PcL toward a wider range of substrates. A two-step modeling procedure, namely, docking experiments followed by construction of tetrahedral intermediates, was used for the simulation of the involved enzyme-substrate recognition/hydrolysis processes. The study of the recognition process (docking experiments) led to unambiguous identification of the binding geometry for the two enantiomeric series of substrates, but did not suggest a definitive interpretation of the behavior of PcL. Taking into consideration the stereoelectronic requirements of the enzymatic hydrolysis reaction, both the enantioselectivity and tolerance of the enzyme were then explained through the study of the tetrahedral intermediates, in turn constructed from the calculated docking geometries of 1a-12a.

Plasma endothelin is increased in early essential hypertension

Local vascular generation of endothelin-1 (ET-1) may contribute to elevated peripheral resistance in hypertension. We tested the hypothesis that immunoreactive ET production in the forearm circulation is increased in early essential hypertensive subjects. Ten young, previously untreated male patients with mild essential hypertension and no signs of target organ damage were compared with matched normotensive subjects in an outpatient setting. Arterial and venous samples were obtained from indwelling catheters in the brachial artery and the medial cubital vein, respectively. Samples were collected at baseline and after induction of endothelium-dependent (acetylcholine) vasodilation. Immunoreactive ET (ET) was measured after column extraction by a sensitive radioimmunoassay employing a C-terminal ET-1 antibody with negligible cross-reaction to big-ET. Individual recovery rates were determined for each sample. Basal ET was significantly higher in hypertensive than in normotensive subjects, both in venous and arterial samples (P < .01). This difference was also present after correction for recovery (P < .01). There was no significant difference between venous and arterial ET concentrations. Local vasodilation did not change arterial or venous ET levels. In conclusion, plasma ET is increased in young, untreated, essential hypertensive subjects with no signs of target organ damage. The increased circulating immunoreactive ET may point to a role for the peptide early in the development of high blood pressure.

[The study of hydrolysis of new lipid-like substrates and trilaurin in monolayers catalyzed with the lipase from Pseudomonas fluorescens]

A simple method for determining the enzymic hydrolysis parameters of lipid-like substrates and trilaurin assembled in monolayers at the water-air interface was suggested. At a surface pressure of 10 mN/m, the initial rates of lipolysis were found to be proportional to the decrease in area of the substrate monolayer caused by the enzymic hydrolysis in a single-compartment Langmuir balance. The kinetic parameters for the hydrolysis of trilaurin and three 1,3-dilaurylpseudoglycerides acetylated in position 2 with an amino acid (phenylalanine, leucine, or valine) catalyzed with lipase from Pseudomonas fluorescens were determined. Unlike models of enzymic hydrolysis that neglect the thickness of the substrate monolayer, our method allows the determination of kinetic parameters in standard dimensions. The values of kcat for the synthetic pseudoglycerides were found to be significantly higher than that for trilaurin, while the values of Km(app) were close. This may be due to the presence of positively charged primary amino groups in the molecules of pseudoglycerides.

The place of Callimico goeldii in the Callitrichine phylogenetic tree: evidence from von Willebrand factor gene intron II sequences

Sequences of a 0.9-kb DNA segment spanning intron 11 of the von Willebrand Factor gene (vWF) were determined for 21 individuals of 19 primate species. The results of maximum parsimony and maximum likelihood analyses of these vWF sequences are congruent with previous molecular findings from other nonlinked nuclear genomic loci which divide the platyrrhine superfamily Ceboidea into three monophyletic families: Cebidae, Atelidae, and Pitheciidae. The vWF results strongly support the taxon Callitrichinae as a monophyletic subfamily within Cebidae. The four extant callitrichine genera constitute tribe Callitrichini, and the basal branchings within this tribe first separate out Saguinus (tamarins), next Leontopithecus (lion tamarins), and last the sister genera Callimico (Goeldi's monkeys) and Callithrix (marmosets). Callithrix divides into three subclades, with pygmy marmosets (C. pygmaea) as sister of the C. argentata species group and with the C. jacchus species group as their sister. Fossil and DNA evidence place the emergence of the callitrichine clade in the basal cebid radiation at about 20 Ma (million years ago) and the three basal branchings in the callitrichin radiation at about 13 to 11 Ma. In turn, the branchings separating the three subclades of Callithrix are placed at about 5 to 4 Ma.

Genetic diversity of two African and sixteen South American populations determined on the basis of six hypervariable loci

A total of 582 individuals (1,164 chromosomes) from two African, eight African-derived South American, five South American Amerindian, and three Brazilian urban populations were studied at four variable number of tandem repeat (VNTR) and two short tandem repeat (STR) hypervariable loci. These two sets of loci did not show distinct allele profiles, which might be expected if different processes promoted their molecular differentiation. The two African groups showed little difference between them, and their intrapopulational variation was similar to those obtained in the African-derived South American communities. The latter showed different degrees of interpopulation variability, despite the fact that they presented almost identical average degrees of non-African admixture. The F(ST) single locus estimates differed in the five sets of populations, probably due to genetic drift, indicating the need to consider population structure in the evaluation of their total variability. A high interpopulational diversity was found among Amerindian populations in relation to Brazilian African-derived isolated communities. This is probably a consequence of the differences in the patterns of gene flow and genetic drift that each of these semi-isolated groups experienced.

Molecular phylogeny of ateline new world monkeys (Platyrrhini, atelinae) based on gamma-globin gene sequences: evidence that brachyteles is the sister group of lagothrix

Nucleotide sequences, each spanning approximately 7 kb of the contiguous gamma1 and gamma2 globin genomic loci, were determined for seven species representing all extant genera (Ateles, Lagothrix, Brachyteles, and Alouatta) of the New World monkey subfamily Atelinae. After aligning these seven ateline sequences with outgroup sequences from several other primate (non-ateline) genera, they were analyzed by maximum parsimony, maximum likelihood, and neighbor-joining algorithms. All three analyzes estimated the same phylogenetic relationships: [Alouatta [Ateles (Brachyteles, Lagothrix)]]. Brachyteles and Lagothrix are sister-groups supported by 100% of bootstrap replications in the parsimony analyses. Ateles joins this clade, followed by the basal genus Alouatta; these joinings were strongly supported, again with 100% bootstrap values. This cladistic pattern for the four ateline genera is congruent with that obtained in previous studies utilizing epsilon-globin, IRBP, and G6PD nuclear genomic sequences as well as mitochondrial COII sequences. Because the number of aligned nucleotide positions is much larger in the present datasetoff than in any of these other datasets, much stronger support was obtained for the cladistic classification that divides subfamily Atelinae into tribes Alouattini (Alouatta) and Atelini, while the latter divides into subtribes Atelina (Ateles) and Brachytelina (Brachyteles and Lagothrix).

Electrophoretic polymorphisms and their taxonomic implications in Callitrichini (Primates, Platyrrhini)

Five hundred forty-three blood samples from 15 populations of the four genera of callitrichin primates were studied electrophoretically. Polymorphism and genetic distances were estimated for 20 loci, 13 of which were polymorphic. The lion tamarin (Leontopithecus) studied here exhibited the least variability for these loci, while the monospecific Cebuella showed the most. The genetic distances observed between Callithrix and Cebuella genera support previous evidence indicating a close taxonomic relationship between them. Genetic distance values obtained in this study also support the synonimyzation of the kuhli form with Callithrix jacchus penicillata.

Evaluation of nurses' errors associated in the preparation and administration of medication in a pediatric intensive care unit

The objectives of this study were to determine the frequency and the types of errors which occur regarding the preparation and the administration of medication and to identify the main causes of these errors in a pediatric intensive care unit (PICU) at the University Hospital in Lausanne (Switzerland). In this prospective study, based on the observation of nurses' activities, the data were collected over a period of 10 weeks. The error classification was based on the American Society of Hospital Pharmacy (ASHP) definitions. The frequency of errors was calculated as the sum of all noted errors divided by the total administered drugs, plus the sum of all omitted drugs, multiplied by 100. The sum of all given doses plus all omitted doses gives the 'total opportunity for errors'. This total was 275 and the total frequency of errors was 26.9%. The most frequent errors were wrong-time errors (32.4%), wrong-administration-technique errors (32.4%) and preparation errors (23.0%). In relation with other studies conducted under comparable conditions, a lesser number of omissions and wrong-time errors were observed. On the contrary, administration-technique and dose-preparation errors were more frequent at our hospital. A program of systematic assistance and survey by professional pharmacists could improve the quality of the preparation and administration of medication in the PICU.

Protein and hypervariable tandem repeat diversity in eight African-derived South American populations: inferred relationships do not coincide

We compared data from individuals living in 4 African Venezuelan and 4 African Brazilian communities for 11 protein loci (551 subjects) and 8 hypervariable tandem repeat polymorphisms (252 subjects). There is heterogeneity in diversity within and between the two sets of loci. On the other hand, African-derived Brazilians and Venezuelans do not present marked variability differences between themselves. Although the hypervariable loci show gene diversities that are about four times higher than those obtained from the protein data, they are not more discriminative at the interpopulation level (averages 6% and 4%, respectively). Interpopulation differences do not strictly parallel the geographic distances between the groups, and population relationships obtained from the protein data are not the same as those indicated by hypervariable tandem repeat polymorphisms. Caution is needed in establishing relationships considering just one level of the biological hierarchy.

Molecular genetics of spectral tuning in New World monkey color vision

Although most New World monkeys have only one X-linked photopigment locus, many species have three polymorphic alleles at the locus. The three alleles in the squirrel monkey and capuchin have spectral peaks near 562, 550, and 535 nm, respectively, and the three alleles in the marmoset and tamarin have spectral peaks near 562, 556, and 543 nm, respectively. To determine the amino acids responsible for the spectral sensitivity differences among these pigment variants, we sequenced all exons of the three alleles in each of these four species. From the deduced amino acid sequences and the spectral peak information and from previous studies of the spectral tuning of X-linked pigments in humans and New World monkeys, we estimated that the Ala --> Ser, Ile --> Phe, Gly --> Ser, Phe --> Tyr, and Ala --> Tyr substitutions at residue positions 180, 229, 233, 277, and 285, respectively, cause spectral shifts of about 5, -2, -1, 8, and 15 nm. On the other hand, the substitutions His --> Tyr, Met --> Val or Leu, and Ala --> Tyr at positions 116, 275, and 276, respectively, have no discernible spectral tuning effect, though residues 275 and 276 are inside the transmembrane domains. Many substitutions between Val and Ile or between Val and Ala have occurred in the transmembrane domains among the New World monkey pigment variants but apparently have no effect on spectral tuning. Our study suggests that, in addition to amino acid changes involving a hydroxyl group, large changes in residue size can also cause a spectral shift in a visual pigment.

Sequences of the primate epsilon-globin gene: implications for systematics of the marmosets and other New World primates

Sequences of the epsilon-globin gene were determined for five species of marmosets, along with approximately 2 kb of 5' flanking sequence. An analysis of these data, compared with those of other primates strongly supports the classification of Callithrix jacchus and C. geoffroyi into the jacchus group, and C. argentata and C. mauesi into the argentata group. The pygmy marmoset, formerly identified as Cebuella pygmaea joined strongly to the argentata group, indicating that without the pygmy marmoset the genus Callithrix would be paraphyletic. Our data support recent studies which indicate that C. pygmaea should be included in the genus Callithrix. Relationships among other primates were as indicated by previous studies of epsilon-globin sequences. Divergence times were estimated according to a local molecular clock. These calculations indicated the divergence of C. mauesi and C. argentata to be approximately 1.6-1.9 Myr (million years ago), and the most recent common ancestor of the marmosets to be between 4.5 and 4.7 Myr. The latter estimate corresponds well to the date of 4.6 Myr calculated from an independent data set.

Marmoset phylogenetics, conservation perspectives, and evolution of the mtDNA control region

Marmosets (genus Callithrix) are a diverse group of platyrrhine primates with 13-15 purported taxa, many of them considered endangered. Morphological analyses constitute most of the basis for recognition of these forms as distinct taxa. The purpose of this study was to provide a molecular view, based on mitochondrial control region sequences, of the evolutionary history of the marmosets, concomitant with a molecular phylogenetic perspective on species diversity within the group. An additional purpose was to provide the first comparative examination of a complete New World monkey control region sequence with those of other mammals. The phylogenetic analyses provide convincing support for a split between the Atlantic forest and Amazonian marmosets, with the inclusion of the pygmy marmoset (Cebuella pygmaea) at the base of the Amazonian clade. The earliest branch of the Atlantic forest group was C. aurita. In the Amazonian group, the analyses do not support the recognition of C. humeralifer and the recently described C mauesi as distinct taxa. They do, however, support a clear distinction between C. argentata and a strongly supported mixed clade of C. humeralifer and C. mauesi. In the Atlantic forest group, the phylogenetic tree suggests mixing between C. penicillata, C. kuhli, and possibly C. jacchus. Most of the sequence features characteristic of other mammal control regions were also evident in marmosets, with the exception that conserved sequence blocks (CSBs) 2 and 3 were not clearly identifiable. Tandem repeat units often associated with heteroplasmy in a variety of other mammals were not evident in the marmoset sequences.

Identification of pre-gamma-globin

A pre-gamma-globin species was identified by high performance liquid chromatography in platyrrhine primates. Although pre-gamma-globin has not been observed in human hemoglobin, its identification in platyrrhine hemoglobin was facilitated by the functional inactivation of one of the duplicated gamma-globin genes in platyrrhines, which simplified the high performance liquid chromatography elution pattern. Part, but not all, of the pre-gamma was glutathionyl gamma 2-globin, and matrix-assisted laser desorption/ionization mass spectrometry was used to demonstrate that the glutathionyl residue was located on cysteine 93. As this residue is invariant in primates, it is predicted that the formation of glutathionyl gamma-globin will be seen in all primate hemoglobins under appropriate conditions.

Reduction of two functional gamma-globin genes to one: an evolutionary trend in New World monkeys (infraorder Platyrrhini)

Nucleotide sequences were determined for the gamma1- and gamma2-globin loci from representatives of the seven anciently separated clades in the three extant platyrrhine families (Atelidae, Pitheciidae, and Cebidae). These sequences revealed an evolutionary trend in New World monkeys either to inactivate the gamma1 gene or to fuse it with the gamma2 gene, i.e. to have only one functional fetally expressed gamma gene. This trend is clearly evident in six of the seven clades: (i) it occurred in atelids by deletion of most of the gamma1 gene in the basal ancestor of this clade; (ii-iv) in pitheciid titi, saki, and cebid capuchin monkeys by potentially debilitating nucleotide substitutions in the proximal CCAAT box of the gamma1 promoters and (v and vi) in cebid owl and squirrel monkeys by crossovers that fused 5' sequence from gamma1 with 3' sequence from gamma2. In the five clades with gamma1 and gamma2 loci separated by intergenic sequences (the fifth clade being the cebid marmosets), the gamma2 genes retained an unaltered proximal CCAAT motif and their gamma2 promoters accumulated fewer nucleotide substitutions than did the gamma1 promoters. Thus, phylogenetic considerations indicate that the stem platyrrhines, ancestral to all New World monkeys, had gamma2 as the primary fetally expressed gamma gene. A further inference is that when the earlier stem anthropoid gamma gene duplicated, gamma2 (at its greater downstream distance from epsilon) could evade embryonic activation by the locus control region but could be fetally activated once released by regulatory mutations from fetal repressors.

Fetal globin expression in New World monkeys

Reverse phase chromatography of the globin chains of adult, newborn, and fetal erythrocytes from three species of New World monkeys (Cebus apella, Aotus azarae, and Callithrix jacchus) representing three of the seven platyrrhine clades showed that gamma-globin expression was fetal in these animals. The globins were identified by a combination of chemical sequencing and mass spectrometric analysis. Since gamma-globin expression is fetal in the other major simian branch, the catarrhines, but embryonic in prosimian primates and nonprimate placental mammals, the evolution of fetal recruitment can now be assigned to the period between the simian-prosimian divergence (55 million years ago) and the platyrrhine-catarrhine divergence (35 million years ago). The gamma-globin gene underwent tandem duplication during the same evolutionary epoch, in accord with a model that suggests that the downstream duplicated gamma-gene (gamma2) was free to acquire the mutations necessary for fetal recruitment. Mass spectrometric analysis of tryptic digests of the gamma-globins verified the amino acid sequences deduced from genomic sequencing. Detailed analysis of high performance liquid chromatography and matrix-assisted laser desorption/ionization mass spectrometry data showed that gamma2-globin in Cebus was expressed to a far greater extent than gamma1-globin, supporting inferences drawn from a study of the promoter sequences. A "pre-gamma"-globin was observed in C. apella and shown to be primarily the glutathionyl adduct. The other species, A. azarae and C. jacchus, also express only one gamma-globin polypeptide. This work provides biochemical evidence of an evolutionary trend in the platyrrhines to alter the duplicated gamma-globin gene locus so that only one gamma-globin polypeptide is expressed.

Molecular phylogeny of the New World monkeys (Platyrrhini, primates) based on two unlinked nuclear genes: IRBP intron 1 and epsilon-globin sequences

Nuclear sequences of the 1.8 kilobase (kb) long intron 1 of the interstitial retinol-binding protein gene (IRBP), previously determined for 11 of the 16 extant genera of New World monkeys (superfamily Ceboidea, infraorder Platyrrhini), have now been determined for the remaining 5 genera. The maximum parsimony trees found, first with IRBP sequences alone and then with tandemly combined IRBP and epsilon-globin gene sequences from the same species, supported a provisional cladistic classification with the following clusters. Subtribes Callitrichina (Callithrix, Cebuella), Callimiconina (Callimico), Leontopithecina (Leontopithecus) and Saguina (Saguinus) constitute subfamily Callitrichinae, and subfamilies Callitrichinae, Aotinae (Aotus), and Cebinae (Cebus, Saimiri) constitute family Cebidae. Subtribes Chiropotina (Chiropotes, Cacajao) and Pitheciina (Pithecia) constitute tribe Pitheciini; and tribes Pitheciini and Callicebini (Callicebus) constitute subfamily Pitheciinae. Subtribes Brachytelina (Brachyteles, Lagothrix) and Atelina (Ateles) constitute tribe Atelini, and tribes Atelini and Alouattini (Alouatta) constitute subfamily Atelinae. The parsimony results were equivocal as to whether Pitheciinae should be grouped with Atelinae in family Atelidae or have its own family Pitheciidae. The cladistic groupings of extant ceboids were also examined by different stochastic evolutionary models that employed the same stochastic process of nucleotide substitutions but alternative putative phylogenetic trees on which the nucleotide substitutions occurred. Each model, i.e., each different tree, predicted a different multinomial distribution of nucleotide character patterns for the contemporary sequences. The predicted distributions that were closest to the actual observed distributions identified the best fitting trees. The cladistic relationships depicted in these best fitting trees agreed in almost all cases with those depicted in the maximum parsimony trees.

Laparoscopic varicocelectomy for infertility. An initial report from Saudi Arabia

OBJECTIVE

To evaluate laparoscopic varicocelectomy for the treatment of infertility in Saudi males.

METHODS

Between January 1992 and July 1994, laparoscopic varicocele repair was performed at Saudi Aramco Dhahran Health Center, in 48 patients, 8 for pain and 40 for infertility.

RESULTS

The 8 patients with pain improved postoperatively. As for those with infertility, 63% had an improved sperm count and 66% showed increased sperm motility. Thirty percent had no change in motility or count.

CONCLUSION

Laparoscopic varicocelectomy is a simple and safe technique with good results and can be performed as day surgery with early return to normal activity.

DNA evidence on the phylogenetic systematics of New World monkeys: support for the sister-grouping of Cebus and Saimiri from two unlinked nuclear genes

Previous inferences from epsilon-globin gene sequences on cladistic relationships among the 16 extant genera of Ceboidea (the New World monkeys) were tested by strength of grouping and bootstrap values for the clades in the most parsimonious trees found: for this epsilon data set enlarged with additional Cebus and Saimiri orthologues; for another nuclear DNA sequence data set consisting of IRBP (interstitial retinol-binding protein gene) intron 1 orthologues; and for tandemly combined epsilon and IRBP sequences. Different ceboid species of the same genus always grouped strongly together as demonstrated by results on Cebus (capuchin monkeys), Saimiri (squirrel monkeys), Callicebus (titi monkeys), Aotus (night monkeys), Ateles (spider monkeys), and Alouatta (howler monkeys). Other strong groupings that could be represented as monophyletic taxa in a cladistic classification were: Cebuella (pygmy marmoset) and Callithrix (marmoset) into subtribe Callitrichina; Callitrichina, Callimico (Goeldi's monkey), Leontopithecus (lion tamarin), and Saguinus (tamarin) into subfamily Callitrichinae; Callitrichinae, Aotus, Cebus, and Saimiri into family Cebidae; Cacajao (uakari monkey) and Chiropotes (saki) into subtribe Chiropotina; Chiropotina and Pithecia (bearded saki) into tribe Pitheciini; Pitheciini and Callicebus into subfamily Pitheciinae; Brachyteles (woolly spider monkey), Lagothrix (woolly monkey), and Ateles into tribe Atelini; and Atelini and Alouatta into subfamily Atelinae. In addition the epsilon and IRBP results congruently grouped (but at lesser strengths) Brachyteles and Lagothrix into subtribe Brachytelina within Atelini, and also Cebus and Saimiri into subfamily Cebinae within Cebidae. Because the IRBP results weakly grouped Pitheciinae with Cebidae, whereas the epsilon results weakly grouped Pitheciinae with Atelinae, the present evidence is best represented in an interim cladistic classification of ceboids by dividing the superfamily Ceboidea into three families: Atelidae, Pitheciidae, and Cebidae.

Fate of a redundant gamma-globin gene in the atelid clade of New World monkeys: implications concerning fetal globin gene expression

Conclusive evidence was provided that gamma 1, the upstream of the two linked simian gamma-globin loci (5'-gamma 1-gamma 2-3'), is a pseudogene in a major group of New World monkeys. Sequence analysis of PCR-amplified genomic fragments of predicted sizes revealed that all extant genera of the platyrrhine family Atelidae [Lagothrix (woolly monkeys), Brachyteles (woolly spider monkeys), Ateles (spider monkeys), and Alouatta (howler monkeys)] share a large deletion that removed most of exon 2, all of intron 2 and exon 3, and much of the 3' flanking sequence of gamma 1. The fact that two functional gamma-globin genes were not present in early ancestors of the Atelidae (and that gamma 1 was the dispensible gene) suggests that for much or even all of their evolution, platyrrhines have had gamma 2 as the primary fetally expressed gamma-globin gene, in contrast to catarrhines (e.g., humans and chimpanzees) that have gamma 1 as the primary fetally expressed gamma-globin gene. Results from promoter sequences further suggest that all three platyrrhine families (Atelidae, Cebidae, and Pitheciidae) have gamma 2 rather than gamma 1 as their primary fetally expressed gamma-globin gene. The implications of this suggestion were explored in terms of how gene redundancy, regulatory mutations, and distance of each gamma-globin gene from the locus control region were possibly involved in the acquisition and maintenance of fetal, rather than embryonic, expression.

Evidence on primate phylogeny from epsilon-globin gene sequences and flanking regions

Phylogenetic relationships among various primate groups were examined based on sequences of epsilon-globin genes. epsilon-globin genes were sequenced from five species of strepsirhine primates. These sequences were aligned and compared with other known primate epsilon-globin sequences, including data from two additional strepsirhine species, one species of tarsier, 19 species of New World monkeys (representing all extant genera), and five species of catarrhines. In addition, a 2-kb segment upstream of the epsilon-globin gene was sequenced in two of the five strepsirhines examined. This upstream sequence was aligned with five other species of primates for which data are available in this segment. Domestic rabbit and goat were used as outgroups. This analysis supports the monophyly of order Primates but does not support the traditional prosimian grouping of tarsiers, lorisoids, and lemuroids; rather it supports the sister grouping of tarsiers and anthropoids into Haplorhini and the sister grouping of lorisoids and lemuroids into Strepsirhini. The mouse lemur (Microcebus murinus) and dwarf lemur (Cheirogaleus medius) appear to be most closely related to each other, forming a clade with the lemuroids, and are probably not closely related to the lorisoids, as suggested by some morphological studies. Analysis of the epsilon-globin data supports the hypothesis that the aye-aye (Daubentonia madagascariensis) shares a sister-group relationship with other Malagasy strepsirhines (all being classified as lemuroids). Relationships among ceboids agree with findings from a previous epsilon-globin study in which fewer outgroup taxa were employed. Rates of molecular evolution were higher in lorisoids than in lemuroids.

Carba analogues of triglycerides--isosteric mimics for natural lipids. Novel substrates for the determination of regio- and enantioselectivities displayed by lipases

The novel carba analogues 1a,b and 2 were synthesized and demonstrated to be isosteric identical mimics for natural triglycerides. They can be used for the system independent determination of regio- and enantioselectivities displayed by lipases. They are, moreover, attractive starting materials for novel carba analogues of phospholipids, PAF analogues and PAF antagonists.

Molecular phylogeny of the New World monkeys (Platyrrhini, primates)

Phylogenetic relationships among the 16 extant genera of Ceboidea (the New World monkeys) were examined using aligned epsilon-globin gene sequences from 19 New World monkeys (representing all 16 extant ceboid genera), and seven catarrhines (one Old World monkey and six hominoids) and tarsier as the outgroups. The consensus maximum parsimony tree found for these epsilon-globin sequences and the levels of support from parsimony and bootstrap analyses, for the clades in this tree, provided strong evidence for a cladistic classification with the following clusters. Subtribes Callitrichina (Callithrix, Cebuella), Callimiconina (Callimico), Leontopithecina (Leontopithecus), and Saguina (Saguinus) constitute subfamily Callitrichinae, and subfamilies Callitrichinae, Aotinae (Aotus), Saimiriinae (Saimiri), and Cebinae (Cebus) constitute family Cebidae. In turn, subtribes Chiropotina (Chiropotes, Cacajao) and Pitheciina (Pithecia) constitute tribe Pithecini, tribes Pitheciini and Callicebini (Callicebus) constitute subfamily Pitheciinae, tribes Atelini (Brachyteles, Lagothrix, Ateles) and Alouattini (Alouatta) constitute subfamily Atelinae, and subfamilies Pitheciinae and Atelinae constitute family Atelidae. The two families (Cebidae and Atelidae) constitute the Ceboidea, the only extant superfamily of infraorder Platyrrhini. The sister-group relationships of Brachyteles and Lagothrix, Saguinus and Leontopithecus, and Callimico with a Cebuella/Callithrix clade is not as well supported by the parsimony and bootstrap analyses. Therefore, these relationships are not incorporated in the proposed cladistic classification. On determining branch lengths for the ceboid phylogenetic tree from only the more freely evolving noncoding sequences at the epsilon-globin locus and taking the reference age of 35 million years ago (MYA) for the New World monkey-catarrhine branch point, we estimated the age of the atelid-cebid branch point as about 20 MYA, and the ages of the next branch points, those between the subfamilies in each family, as 19-16 MYA.

Divergence between biochemical and cytogenetic differences in three species of the Callicebus moloch group

Specimens from three species of the Callicebus moloch group--C. moloch (N = 80), C. brunneus (N = 166), and C. cupreus (N = 23)--were studied. Twenty genetic loci were investigated through electrophoresis, genetic distances were estimated, and the results compared with the available cytogenetic data. Low values of genetic distance were encountered, contrasting with relatively large chromosome differences. We propose that recent karyotypic rearrangements, rather than other Pleistocene events, were the major evolutionary mechanisms determining speciation in these three taxa.

Chromatographic resolution of chiral intermediates in beta-adrenergic blocker synthesis on chiral stationary phases

The enantiomeric purities of optically active intermediates for beta-adrenergic blocking agents prepared via enzyme-assisted processes can be determined rapidly and with high accuracy using HPLC on commercially available columns with chiral supports [Chiralcel OD, OB; Chiralpak OT(+)]. The dependence of the resolution parameters on the substitution pattern of both hydroxy compounds and their esters is reported.

Genetic studies in three South American black populations

Twenty-one genetic systems were investigated in three relatively isolated South American Black populations. Unexpected allele frequencies were found in different systems in all populations, suggesting the occurrence of genetic drift and/or founder effects. The estimates of racial admixture indicate 50% to 79% of Black ancestry, with various degrees of White (18%-28%) and Amerindian (3%-32%) ancestry.

Coat color and biochemical variation in Amazonian wild populations of Alouatta belzebul

A comparative study of 13 blood genetic systems and pelage color variation was performed in four wild populations of Alouatta belzebul. The animals from the west bank of the Tocantins River showed less color variation than those from the east bank, as well as less than those from Tocantins Island. The blood genetic markers, however, revealed an opposite pattern of variation. A previously undescribed morphological variant (completely red) was observed in one specimen of the east bank, where pelage color of the local population varied from completely black to completely red. Levels of heterozygosity and inter- and intralocus variances for the blood systems are compared with those observed in five other species of New World primates.

Transferrin and albumin polymorphisms in buffaloes from Brazil

Starch gel electrophoresis disclosed six transferrin phenotypes, explainable by three alleles (TF A, TF D, TF E), and three albumin phenotypes, determined by two alleles (ALB A, ALB B). Their prevalences suggest that the Brazilian populations have admixed river and swamp buffalo ancestry, the frequency of ALB A being much higher than those found in other regions.