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1.
Arthritis Rheumatol ; 69(8): 1538-1551, aug. 2017.
Artigo em Inglês | BINACIS | ID: biblio-965260

RESUMO

OBJECTIVE: This collaboration between the American College of Rheumatology and the American Association of Hip and Knee Surgeons developed an evidence-based guideline for the perioperative management of antirheumatic drug therapy for adults with rheumatoid arthritis (RA), spondyloarthritis (SpA) including ankylosing spondylitis and psoriatic arthritis, juvenile idiopathic arthritis (JIA), or systemic lupus erythematosus (SLE) undergoing elective total hip (THA) or total knee arthroplasty (TKA). METHODS: A panel of rheumatologists, orthopedic surgeons specializing in hip and knee arthroplasty, and methodologists was convened to construct the key clinical questions to be answered in the guideline. A multi-step systematic literature review was then conducted, from which evidence was synthesized for continuing versus withholding antirheumatic drug therapy and for optimal glucocorticoid management in the perioperative period. A Patient Panel was convened to determine patient values and preferences, and the Grading of Recommendations Assessment, Development and Evaluation methodology was used to rate the quality of evidence and the strength of recommendations, using a group consensus process through a convened Voting Panel of rheumatologists and orthopedic surgeons. The strength of the recommendation reflects the degree of certainty that benefits outweigh harms of the intervention, or vice versa, considering the quality of available evidence and the variability in patient values and preferences. RESULTS: The guideline addresses the perioperative use of antirheumatic drug therapy including traditional disease-modifying antirheumatic drugs, biologic agents, tofacitinib, and glucocorticoids in adults with RA, SpA, JIA, or SLE who are undergoing elective THA or TKA. It provides recommendations regarding when to continue, when to withhold, and when to restart these medications, and the optimal perioperative dosing of glucocorticoids. The guideline includes 7 recommendations, all of which are conditional and based on low- or moderate-quality evidence. CONCLUSION: This guideline should help decision-making by clinicians and patients regarding perioperative antirheumatic medication management at the time of elective THA or TKA. These conditional recommendations reflect the paucity of high-quality direct randomized controlled trial data.


Assuntos
Humanos , Artrite Reumatoide , Artroplastia de Quadril , Artroplastia do Joelho , Ortopedia , Piperidinas/uso terapêutico , Artrite Juvenil , Pirimidinas/uso terapêutico , Pirróis/uso terapêutico , Reumatologia , Espondilite Anquilosante , Produtos Biológicos , Doenças Reumáticas , Doenças Reumáticas/tratamento farmacológico , Antirreumáticos/uso terapêutico , Assistência Perioperatória , Inibidores de Proteínas Quinases/uso terapêutico , Glucocorticoides/uso terapêutico , Imunossupressores , Lúpus Eritematoso Sistêmico/tratamento farmacológico
2.
Mol Phylogenet Evol ; 13(2): 392-404, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10603266

RESUMO

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.


Assuntos
Callimico/genética , Callitrichinae/genética , Íntrons/genética , Filogenia , Fator de von Willebrand/genética , Animais , Sequência de Bases , Callimico/classificação , Callitrichinae/classificação , DNA/química , DNA/genética , Evolução Molecular , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Fatores de Tempo
3.
Am J Public Health ; 89(8): 1254-5, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10432919

RESUMO

OBJECTIVES: This article describes the effort to eliminate measles from Jamaica and its impact on measles incidence. METHODS: In addition to routine measles vaccination, the Jamaican Ministry of Health implemented a strategy of a 1-time-only catch-up vaccination campaign, conducted in 1991, and periodic follow-up campaigns, the first of which occurred in 1995. RESULTS: Since 1991, despite careful surveillance, no serologically confirmed indigenous cases of measles have occurred in Jamaica. CONCLUSIONS: Measles virus circulation has been interrupted in Jamaica. The Jamaican experience provides further evidence that global measles eradication is achievable.


Assuntos
Programas de Imunização/organização & administração , Sarampo/prevenção & controle , Adolescente , Criança , Pré-Escolar , Humanos , Incidência , Lactente , Jamaica/epidemiologia , Sarampo/epidemiologia , Vigilância da População
4.
J Pediatr ; 131(2): 233-9, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9290609

RESUMO

OBJECTIVE: We determined the sensitivity and specificity of neonatal brain-stem auditory evoked potentials (BAEP) as markers for subsequent hearing impairment and for developmental problems found later in infancy and childhood. METHODS: BAEP studies were performed before discharge in infants treated with extracorporeal membrane oxygenation (ECMO), and two specific abnormalities were analyzed: elevated threshold and delayed central auditory conduction. Behavioral audiometry was repeated during periodic follow-up until reliable responses were obtained for all frequencies, and standardized developmental testing was also conducted. The sensitivity and specificity of an elevated threshold on the neonatal BAEP for detecting subsequent hearing loss, and the relationship of any neonatal BAEP abnormality to language or developmental disorders in infancy, were calculated. RESULTS: Test results for 46 ECMO-treated infants (57.5%) were normal, and those for 34 infants (42.5%) were abnormal, with either elevated wave V threshold, prolonged wave I-V interval, or both on neonatal BAEP recordings. Most significantly, 7 (58%) of the 12 children with subsequent sensorineural hearing loss had left the hospital after showing normal results on threshold tests. There was no significant difference in the frequency of hearing loss between subjects with abnormal (5/21, or 24%) and those with normal BAEP thresholds (7/59, or 12%; Fisher Exact Test, p = 0.28). Therefore the sensitivity of neonatal BAEP testing for predicting subsequent hearing loss was only 42%. Neonatal BAEP specificity for excluding subsequent hearing loss was 76%. In contrast, on language development testing, 19 children demonstrated receptive language delay. Of these children, 12 (63%) had abnormal neonatal BAEP recordings and 7 (37%) had a normal BAEP threshold, normal central auditory conduction test results, or both (p = 0.04). CONCLUSIONS: Neonatal BAEP threshold recordings were of limited value for predicting subsequent hearing loss common in ECMO-treated survivors. However, an abnormal neonatal BAEP significantly increased the probability of finding a receptive language delay during early childhood, even in those with subsequently normal audiometry findings. Because neonatal ECMO is associated with a high risk of hearing and receptive language disorders, parents should be counseled that audiologic and developmental follow-up evaluations in surviving children are essential regardless of the results of neonatal BAEP testing.


Assuntos
Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Oxigenação por Membrana Extracorpórea , Transtornos da Audição/diagnóstico , Audição/fisiologia , Transtornos da Linguagem/diagnóstico , Idioma , Testes de Impedância Acústica , Audiometria , Limiar Auditivo/fisiologia , Criança , Pré-Escolar , Aconselhamento , Oxigenação por Membrana Extracorpórea/efeitos adversos , Seguimentos , Previsões , Transtornos da Audição/fisiopatologia , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Lactente , Recém-Nascido , Desenvolvimento da Linguagem , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Transtornos do Desenvolvimento da Linguagem/fisiopatologia , Transtornos da Linguagem/fisiopatologia , Alta do Paciente , Probabilidade , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e Especificidade , Sobreviventes
5.
Am J Phys Anthropol ; 100(2): 153-79, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8771309

RESUMO

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.


Assuntos
Cebidae/genética , Proteínas do Olho , Globinas/genética , Filogenia , Proteínas de Ligação ao Retinol/genética , Animais , Sequência de Bases , Dados de Sequência Molecular
6.
Mol Phylogenet Evol ; 4(3): 331-49, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8845968

RESUMO

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.


Assuntos
Cebidae/genética , Cebus/genética , Mapeamento Cromossômico , DNA/genética , Genes , Globinas/genética , Filogenia , Saimiri/genética , Alouatta/genética , Sequência de Aminoácidos , Animais , Aotus trivirgatus/genética , Sequência de Bases , Callithrix/genética , Cebidae/classificação , Primers do DNA , Ligação Genética , Variação Genética , Hominidae/genética , Humanos , Íntrons , Modelos Genéticos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Saguinus/genética , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico
7.
Proc Natl Acad Sci U S A ; 92(7): 2607-11, 1995 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-7535927

RESUMO

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.


Assuntos
Evolução Biológica , Cebidae/genética , Hemoglobina Fetal/biossíntese , Expressão Gênica , Globinas/genética , Pseudogenes , Alouatta/genética , Animais , Sequência de Bases , Primers do DNA , Éxons , Feto , Ligação Genética , Hominidae/genética , Humanos , Íntrons , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Deleção de Sequência , Homologia de Sequência do Ácido Nucleico
8.
Int J Radiat Oncol Biol Phys ; 28(4): 797-802, 1994 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-8138431

RESUMO

PURPOSE: A multi-institutional experience in radiosurgery for solitary brain metastases was combined to identify factors associated with safety, efficacy, tumor control, and survival. MATERIALS AND METHODS: A review of 116 patients with solitary brain metastases who underwent gamma knife stereotactic radiosurgery at five institutions was performed. The median follow-up was 7 months following radiosurgery and 12 months following diagnosis. Minimum tumor doses varied from 8-30 Gy (mean, 17.5 Gy). Forty-five patients failed prior radiotherapy and 71 had no prior brain irradiation. Fifty-one patients had radiosurgery alone and 65 underwent combined radiosurgery with fractionated large-field radiotherapy (mean dose, 33.8 Gy). RESULTS: Median survival was 11 months after radiosurgery and 20 months after diagnosis. Follow-up documented local tumor control in 99 patients (85%), tumor recurrence in 17 (15%), and documented radiation necrosis in one (1%). The 2-year actuarial tumor control rate was 67 +/- 8%. Tumor histology affected survival (better for breast cancer, p = .004) and local control (better for melanoma and renal cell, p = .0003) in multivariate analyses. Combined fractionated radiotherapy and radiosurgery improved local control (p = 0.111), but not survival in multivariate testing. CONCLUSION: Radiosurgery is effective in controlling solitary brain metastases with low morbidity. Further study is needed to better define optimum treatment parameters for radiosurgery.


Assuntos
Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/cirurgia , Radiocirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/mortalidade , Seguimentos , Humanos , Pessoa de Meia-Idade , Prognóstico , Radiocirurgia/efeitos adversos , Taxa de Sobrevida
9.
Mol Phylogenet Evol ; 2(3): 225-42, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8136923

RESUMO

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.


Assuntos
Cebidae/classificação , Cebidae/genética , DNA/genética , Globinas/genética , Filogenia , Animais , Sequência de Bases , DNA/sangue , DNA/isolamento & purificação , Primers do DNA , Éxons , Geografia , México , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Homologia de Sequência do Ácido Nucleico , América do Sul , Especificidade da Espécie
10.
Am J Bot ; 77(2): 211-225, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30139070

RESUMO

Isozymatic data taken from 67 Guatemalan collections of maize were subjected to numerical taxonomic analyses to elucidate systematic relationships among the 19 maize races and subraces described for Guatemala by Wellhausen et al. As with Bolivian and Mexican races, isozymatic variation in Guatemalan maize was strongly associated with altitude. Guatemalan lowland races were in general isozymatically distinct from races of higher elevations. Two middle elevation Guatemalan races proved difficult to place taxonomically. As a group, Guatemalan highland races were isozymatically more diverse than races from lower elevations, and were rather weakly differentiated from Mexican highland races. Notably, variational patterns evident from phenetic analyses of isozyme data were generally congruent with those apparent in phylogenetic analyses. The data reported here, and in earlier studies, suggested that divergent combinations of isozymatic, karyotypic, and morphological features have evolved in local maize races from Mexico, Guatemala, and Bolivia, perhaps as the result of the different selective regimens indigenous cultivators have imposed on different regional phylogenetic lineages.

11.
Diabetes Res Clin Pract ; 7(3): 205-11, 1989 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-2691218

RESUMO

Recombinant interleukin-1 beta (IL-1 beta) was administered intraperitoneally for 3 days to normal C57BL/6ByJ (B6) mice. The islets from IL-1-treated and control animals were isolated and glucose-stimulated insulin secretion studied in the perifusion system. The total islet insulin content and the ultrastructure of the islets isolated from the animals treated with IL-1 did not differ from those seen in control animals. However, glucose-stimulated insulin release was significantly impaired after 3 days of in vivo administration of IL-1, either 3 micrograms/animal/day or 0.3 micrograms/animal/day. The administration of IL-1 inhibited an acute phase of glucose-induced insulin release, whereas neither basal insulin secretion nor insulin release from 10-30 min of perifusion with glucose was impaired. There was an only partial (27%) and non-significant restoration of the insulin secretory response to glucose stimulation 4 days after discontinuation of IL-1 treatment. We conclude that IL-1 administered in vivo is capable of adversely affecting pancreatic islet response to glucose stimulation. After 3 days of administration, these changes are confined to the process of insulin release, with the islet cell morphology and total insulin content being unaffected.


Assuntos
Insulina/metabolismo , Interleucina-1/farmacologia , Animais , Glicemia/análise , Glucose/farmacologia , Antagonistas da Insulina/farmacologia , Secreção de Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/ultraestrutura , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica
12.
Plast Reconstr Surg ; 84(1): 80-4, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2734407

RESUMO

Osteomyelitis of the clavicle is an uncommon disease, but it should be considered in patients who present with pain, cellulitis, or drainage in the sternoclavicular area following head and neck surgery, irradiation, subclavian vein catheterization, or immunosuppression. An idiopathic presentation is possible. In contrast to primary osteomyelitis of the clavicle, which is occasionally seen in children, secondary osteomyelitis is quite rare. It is often mistaken for a fracture or a possible neoplasm on plain x-rays. Tomograms and CT scanning are confirmatory, and in early cases, technetium-99m bone scanning can be helpful. Treatment must include early, aggressive surgical debridement of all affected tissues, followed by wound coverage with a well-vascularized flap and perioperative antibiotics.


Assuntos
Clavícula/cirurgia , Osteomielite/cirurgia , Abscesso/complicações , Idoso , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteomielite/etiologia , Lesões por Radiação/cirurgia , Infecções Estafilocócicas , Retalhos Cirúrgicos
13.
Genetics ; 90(2): 339-48, 1978 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17248866

RESUMO

To examine the questions of whether the additive and dominance effects present for morphological characters in racial crosses are of sufficient consistency and magnitude to allow such genetic effects to be used for racial classification, we used a diallel experiment among the 25 well-defined Mexican races of maize, which include the ancestral stocks of most commercial and genetic maize types. With such an experiment, genetic effects and genotype by environmental interactions for one or more characters can be used to measure genetic and adaptational or environmental similarity. We used average parental effects (general combining abilities), specific effects, and genotype by environmental effects of 21 characters from the diallel (grown at three locations) to group the Mexican races of maize. The groupings based upon average genetic effects and upon genotype by environmental interactions are more satisfactory than groupings based upon specific effects. The standard errors for genetic distances based upon specific (largely dominance) effects seem to be too high for practical use. Principal components analyses of the same data suggest a similar conclusion.-The groupings based upon average genetic effects are in general agreement with previous studies, with the exception of Maíz Dulce, which is grouped with the Cónicos, rather than being isolated from the other Mexican races of maize.

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