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Biomedical subjects

C A Green

Publications and source records attributed to C A Green.

At least 91 records · Page 5Linked to original sources
PubMed1986

Genetics of esterases and 6-phosphogluconate dehydrogenase in the Anopheles maculatus complex.

Electromorphic variation for some esterases and 6-phosphogluconate dehydrogenase enzymes in the Anopheles maculatus complex is controlled by four loci which are unlinked to sex. Esterase loci are linked to each other: Est-1-36%-Est-4-16.5%-Est-3; but unlinked to Pgd-2. Linkage data were obtained by selfing the F1 generation from selected parents and analysing genotypes in the F2; the classical dihybrid-cross. The analysis consists of testing observed data for goodness of fit to a) ratios expected from Mendelian ratios without linkage and b) if they do not fit then computing a likely degree of linkage and computing expected ratios with such linkage for further tests. Confidence limits are given for the most likely levels of linkage. This method can provide useful information for population-genetic studies on anopheline mosquitoes, whose laboratory rearing is generally difficult. Through indirect evidence, the enzyme loci are correlated to polytene chromosomes. The esterases probably lie on chromosome three (polytene arms 3 and 4) and Pgd-2 on the second chromosome (arms 2 and 5).

Animals↗
PubMed1984

The thermal effects of skeletal fixation-pin insertion in bone.

In human-cadaver cortical bone, we measured the maximum temperatures and the durations of temperatures in excess of 55 degrees Celsius during experimental insertion of five types of external skeletal-immobilization pins. Drill speed, pin-point design, and predrilling were the variables examined. Drill speed was found to have an effect on the maximum temperature and the duration of temperatures in excess of 55 degrees Celsius only in the immediate vicinity of the hole. Pinpoint design was a more significant factor, and predrilling was highly effective as a method of minimizing temperature elevation.

Aged↗
PubMed1984

Cytogenetic studies of some species complexes of Anopheles in Thailand and Southeast Asia.

Recent studies on cytogenetics, behavioral, geographical and distinct morphological characters on adult, pupal and larval stages have revealed that "balabacensis" is a species complex. Anopheles dirus the mainland species, is distributed widely in Thailand and is renowned for its role as primary vector of human malarial parasites. Further, evidence from cytogenetic and taxonomic studies suggests that "An. dirus" is a species complex comprising at least four distinct species provisionally designated: dirus A, B, C and D. These cryptic species are distinguishable only partially morphologically, but can be separated on the basis of metaphase chromosomes using the Giemsa and Hoechst 33258 staining techniques. Apparently, these siblings show distinct patterns of geographic distribution in Thailand and Peninsular Malaysia. The recognition of dirus as a complex of species in Thailand and Peninsular Malaysia requires a re-evaluation of the role that the individual members of this complex have in the transmission of malaria parasites in this region. Cytological analysis of gene rearrangements in ovarian polytene chromosomes has shown that An. maculatus is a sibling-species complex consisting of at least four species in Thailand provisionally designated: maculatus A, B, C and G. These siblings are sympatric in some populations. Furthermore, species B is so highly polymorphic for chromosome rearrangements that four geographic forms can be recognized. It is not known whether these four forms are subspecies or yet further species within the species B complex. These sibling-species must be differentiated in order to understand any differential capabilities in their transmission of human malaria parasites. Anopheles nivipes was elevated from synonymy under An. philippinensis to full species status by Reid, a decision recently confirmed by cross mating experiments. The Thailand Malaria Division does not differentiate these two species and only identifies An. philippinensis, yet, An. nivipes is by far the most common of the two species in Thailand. Furthermore, preliminary surveys of the ovarian polytene chromosomes of several widely separated populations of An. nivipes in Thailand have revealed at least two distinct chromosomal types of nivipes based on fixed inversions on the X chromosomes.

Animals↗
PubMed1983

OSa, a 'new' low-frequency red cell antigen.

A new low-frequency red cell antigen, OSa, in a Japanese blood donor is inherited as a Mendelian dominant. A family study showed that OSa is not controlled by ABO, P1, Rh, Kidd, or Diego loci, nor is the antigen X- or Y-borne.

Antigen-Antibody Reactions↗
PubMed1983

Genetic polymorphism of the LW blood group system.

Family studies of rare LW(a-b+) propositi confirm the recent finding based on frequency studies that the LW blood groups are polymorphic in Finland (Sistonen & Tippett, 1982); they are controlled by two alleles LWa (0.97) and LWb (0.03) independent from most other common blood group loci. Lod scores for LW and the loci for 27 markers are presented.

Alleles↗
PubMed1983

Genetic observations on the taxon Anopheles (Cellia) pharoensis Theobald (Diptera: Culicidae).

A photomap of the ovarian polytene chromosomes from Anopheles pharoensis is presented. The arrangement shown is that found in populations from Zululand, South Africa, and represents the arbitrary standard for the taxon. Two X-chromosome arrangements exist in samples from allopatric natural populations. Crosses between females homozygous for the inverted arrangement, Xa, and males carrying the standard arrangement, X+a, give F1 males that are sterile. Females from this cross, and both males and females from the reciprocal cross, are fertile. The simplest hypothesis is that the two X-chromosome arrangements mark two species within the taxon An. pharoensis Theobald. The practical implications are briefly discussed.

Animals↗
PubMed1980

Chromosomal evidence for sibling species of the malaria vector Anopheles (Cellia) culicifacies Giles.

The ovarian polytene chromosomes of adult Anopheles culicifacies from natural populations in Pakistan, India and Sri Lanka, and from four laboratory colonies (one from Pakistan and three from India) are compared with the published cytological map for this taxon. Two types of X-chromosome exist. One of these is identical with the published map; the other differs by two inversions. No autosome arm rearrangements are detected. A photomap is presented which documents the X-chromosome inversions. Both types of Xs are found in a natural population near New Delhi in the apparent absence of heterozygotes. This is interpreted as evidence for biologically distinct species within the taxon An. culicifacies Giles. The formal taxonomic and practical implications are briefly discussed.

Animals↗
PubMed1978

Biological species in Praomys (Mastomys) natalensis (Smith), a rodent carrier of Lassa virus and bubonic plague in Africa.

Plague has been known from countries surrounding Rhodesia from as early as 1935, but was first reported from Rhodesia in 1974. Part of our investigation of the complex ecosystem involving Yersinia pestis is critical assessment of the evolutionary status of natural populations belonging to formal, taxonomic species of implicated rodents. We present data on chromosomal and hemoglobin variation in sympatric populations and laboratory produced hybrids that give unequivocal evidence for at least two biologicql species in the taxon Praomys (Mastomys) natalensis. We argue for the usefulness of the biological species concept as a basis for any ecological investigation into pathogen biology.

Animals↗
PubMed1975

Distribution of acid and alkaline phosphatases in canine skin.

Azo dye methods were used to determine the distribution of acid phosphatase (ACP) and alkaline phosphatase (ALP) in the skin of 25 Beagle dogs. ALP activity was found in dermal papillae of hair follicles regardless of their state of activity, in Huxley's layer of the inner root sheath of anagen stages, in myoepithelial cells of apocrine sweat glands, in germinative cells of sebaceous glands, in vascular endothelium, and in mast cells. The ACP activity was found in the epidermis, outer and inner root sheaths, keratogenous zone, hair cuticle and medulla, duct of sebaceous gland, and sebum. The results indicate that ACP and ALP are distinctive enzymes serving different biologic functions. The principal role of ALP in the skin appears to be dephosphorylation for adsorption and transport of chemical substances necessary for growth and maintainence of the pilary system and glandular adnexa. The ACP appears to be primarily involved in the breakdown of phospholipids and in necrobiosis of keratinocytes.

Acid Phosphatase↗
PubMed1970

Subtle periodicity of pupation in rapidly developing mosquitos: with particular reference to Aedes vittatus and Aedes aegypti.

Aedes vittatus and Ae. aegypti are important vectors of yellow fever and other arbovirus diseases in Africa and they complete many generations, through all developmental stages, in a single year. Recent studies on Drosophila have offered precise techniques for analysing periodicities in populations of single developmental events in individuals. If the variability of pupation times is low, periodicities may not be recognizable by an obviously polymodal pattern in a single synchronized population. Analysis of 8 synchronized populations of Ae. vittatus and Ae. aegypti, evenly spaced through 24 hours, provided a sensitive method of recognizing even subtle periodicities in rapidly developing mosquitos. By this means Ae. vittatus has been shown to exhibit a weak diurnal periodicity of pupation while a strain of Ae. aegypti showed not the slightest periodicity of pupation under the same light-dark cycle. The authors stress that periodicity of emergence or pupation in mosquitos can have important consequences for epidemiology and vector control and should be verified for each vector species for which control measures are envisaged.

Aedes↗