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Biomedical subjects

R Carter

Publications and source records attributed to R Carter.

At least 361 records · Page 20Linked to original sources
PubMed1977

Control of gamete formation (exflagellation) in malaria parasites.

The only stages of malaria parasites capable of establishing an infection in a mosquito are the gametocytes that circulate in the blood of the veterbrate host. Within minutes of ingestion by a mosquito the gametocytes transform into mature gametes in the process of "exflagellation." This process is controlled in vitro solely by the change in pH in the blood as it moves from the environment of the circulation to that of the atmosphere, the pH rise being mediated by the fall in carbon dioxide tension as the blood equilibrates with the atmosphere.

Air↗
PubMed1977

Kinking of the internal carotid artery. Clinical significance and surgical management.

Observations of a series of fifteen surgically treated coiled and kinked internal carotid arteries are reported. The kinked internal carotid artery may be clinically significant and can cause cerebral infarction, even in the absence of atherosclerosis. Each patient must be thoroughly investigated and evaluated individually. One must distinguish simple tortuosity without blood flow obstruction from critical kinking of the internal carotid artery. If a patient with angiographic confirmation is symptomatic and other causes are eliminated, surgical correction should be carefully considered, especially if rotational cerebral ischemia is present. The surgical treatment of choice is resection of the redundant internal carotid artery with reimplantation and thromboendarterectomy of any associated plaque. Kinking of the internal carotid artery may lead to aneurysm formation requiring a difficult surgical resection. Although the evidence for a precise causal relationship between kinking of the internal carotid artery and cerebrovascular symptoms is sometimes difficult to establish, it is our belief that a more aggressive surgical approach may be warranted in this potentially disabling and even fatal condition.

Adult↗
PubMed1977

Biochemical markers for strain differentiation in malarial parasites.

Genetic differences between micro-organisms can be identified by studying variations in enzyme forms and DNA characteristics. Enzyme electrophoresis has revealed considerable genetic diversity in populations of malarial parasites and has enabled populations reproductively isolated from one another to be identified. Studies on rodent malarial parasites from four regions of Africa have shown that each species and subspecies can be distinguished by its pattern of enzyme forms. In subspecies in which enzyme polymorphism occurs, the frequencies of each combination of enzyme forms suggest an extensive degree of random mating in the population. Populations of Plasmodium falciparum are also enzymically polymorphic, similar enzyme variants being found in isolates from several parts of the world.

Africa↗
PubMed1977

Graffiti and adolescent personality.

Graffiti has been studied for many years from many viewpoints. They have been used to explain accounts of people, styles of life, and assumed relationships. The present paper reports an attempt to analyze graffiti as outward manifestations of adolescent personality. Results suggested that different forms of graffiti could be interpreted from five characterizations of early adolescent personality: sexual maturity, self-identity, idealism, iconoclasm, and rebelliousness. Significant differences were found between boys and girls in numbers of inscriptions for each category. Further, the graffiti were analyzed in relation to early adolescent stages of development.

Adolescent↗
PubMed1976

Fluoride kinetics after enflurane anesthesia in healthy and anephric patients and in patients with poor renal function.

Enflurane, a fluorinated methylethyl ether, is metabolized, in part, to inorganic fluoride. Methoxyflurane has similar metabolism, and cases of fluoride ion-induced renal failure have been reported after its use. This prospective study was initiated to determine fluoride ion kinetics after enflurance anesthesia in 16 healthy patients, 18 anephric patients, and 6 patients each having a creatinine clearance of less than 5 ml/min (on dialysis). Serum and urine inorganic fluoride levels were determined. There was no clinical or statistical significance difference among the 3 groups with respect to maximum inorganic fluoride ion concentration or the time to reach it. The fluoride ion values were never above the 50 muM level that has been reported to cause subclinical renal toxicity. The fluoride ion concentration in serum fell rapidly after termination of anesthesia even in the anephric patients. This is presumed to be due to uptake of the ion by bone. Patients with low creatinine clearance also have low fluoride ion clearance. Statistical but not clinical significance was found in the comparison between pre-enflurane and the 24-hr fluoride ion values in the anephric and low creatine clearance patients, but this did not persist after one dialysis.

Adult↗
PubMed1975

The distribution of enzyme variation in populations of Plasmodium falciparum in Africa.

Isolates of Plasmodium falciparum collected from the east and west coasts of tropical Africa and also from several inland regions have been examined for electrophoretic forms of the enzymes GPI, LDH and 6PGD. Variation within and between isolates was found in the parasite forms of all three enzymes. While not disproving the existence of genetic divisions between P. falciparum populations in Africa the distribution of this variation provides no evidence for such a hypothesis.

Africa, Eastern↗
PubMed1975

Genetic studies on Plasmodium chabaudi: recombination between enzyme markers.

Two lines of Plasmodium chabaudi differing in three characters have been crossed, using a technique previously described for P. yoelii. One line, termed 47AS, was characterized by an electrophoretic form of 6-hosphogluconate dehydrogenase, denoted 6PGD-2, a form of lactate dehydrogenase, denoted LDH-3, and was pyrimethanime-resistant. The second line, termed 10AJ, possessed enzyme forms of 6PGD-3 and LDH-2 and was pyrimethamine-sensitive. The cross was made by permitting mosquitoes to feed on a mixture of the two lines and infecting rodents with the resulting sporozoites. The products of the cross were cloned by dilution and examined for enzyme-type and drug-response. Results showed that recombination had occurred between each of the three characters. Clones characterized by 6PGD-2/LDH-2 and 6PGD-3/LDH-3 demonstrated recombination between the enzyme markers. The drug-resistance character segregated independently of either enzyme marker.

Animals↗
PubMed1975

Sudden increase in virulence in a strain of Plasmodium berghei yoelii.

The mild and chronic 17X strain of Plasmodium berghei yoelii showed a sudden increase in virulence following a period of 110 days in the deep freeze. The enhanced virulence was seen in a very high and early parasite peak in the blood and a 100% mortality of all infected mice. The exalted virulence remained unaltered following a number of blood transfers of the strain and after four cyclical transmissions through Anopheles stephensi. Enzyme pattern studies revealed that the virulent strain possessed the enzyme types GPI-1 and 6 PGD-4,-both characteristic for strain 17X of P.b. yoelii. Studies carried out to investigate the possibility of a concomitant viral infection transferred by blood passage, which could have been responsible for the enhanced virulence and mortality in the infected mice, showed no presence of any detectable virus in the blood of the P.b. yoelii infected mice. It is suggested that virulence may provide a marker in genetic work of rodent plasmodia and be included in association with enzyme and drug resistance markers.

Animals↗
PubMed1975

New observations on the malaria parasites of rodents of the Central African Republic - Plasmodium vinckei petteri subsp. nov. and Plasmodium chabaudi Landau, 1965.

The morphology and enzyme forms of malaria parasites isolated from 50 wild caught specimens of Thamnomys rutilans from the Central African Republic have been studied and three distinct species of Plasmodium identified. One species has been confirmed as Plasmodium yoelii yoelii. Morphological features of both the remaining species correspond to those given by Landau (1965) in her original description of Plasmodium chabaudi. For one of these species the name P. chabaudi has been retained; the other species, which closely resembles subspecies of Plasmodium vinckei from other regions of Africa, has been designated Plasmodium vinckei petteri subsp. nov. P. chabaudi and P.v. petteri are distinguished from each other both in their morphology in the blood and sporogonic stages, and in their enzyme forms.

Animals↗