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Biomedical subjects

M Adams

Publications and source records attributed to M Adams.

At least 271 records · Page 15Linked to original sources
PubMed1989

Genetic characterization of three strains of Hymenolepis diminuta at 39 enzyme loci.

The technique of allozyme electrophoresis was applied to three strains of Hymenolepis diminuta to distinguish between three hypotheses [(1) multiple species, (2) genetically distinct founder stocks and (3) response to differential selection among similar stocks] proposed to account for metabolic differences among strains. There was no evidence from the 39 enzyme loci established that the three strains represented more than one species. In the absence of knowledge of the population structure of H. diminuta in the wild, electrophoretic data herein could not distinguish between the latter hypotheses. Nevertheless, all three strains were distinguishable on electrophoretic profiles and allelic similarities between strains question the view of their proposed origins.

Animals↗
PubMed1989

A genetic approach to species criteria in the amoeba genus Naegleria using allozyme electrophoresis.

The present study employs allozyme electrophoresis to characterize and inter-relate 61 isolates of Naegleria. Diploidy was confirmed, with heterozygotes observed at 29 of the 33 loci established and in all but two isolates. With a single exception, isolates clustered at two levels of similarity, either below 21% or above 52%. It is argued that such a major discontinuity provides a sound biological basis for a species concept in Naegleria. On this basis the present species-level taxonomy does not reflect the genetic diversity of the genus. The study recognized 18 genetic groups of species rank. The subspecies N. australiensis italica deserves specific rank; additional thermophilic species not closely related to N. fowleri and N. lovaniensis are recognized; and N. gruberi as currently conceived is a complex of 10 species, at least five of which are represented in the formal culture collections. Most species are genetically too different for relationships to be elucidated by allozyme electrophoresis, supporting the view that some of the times of divergence within the genus are extremely ancient.

Alleles↗
PubMed1989

Genetic characterization of three species of Onchocerca at 23 enzyme loci.

The technique of allozyme electrophoresis was applied to species of Onchocerca from cattle to increase the number of enzyme loci established and therefore provide a genetic basis for a rational species-level taxonomy. Twenty-three enzyme loci were established and provided unequivocal genetic evidence for the taxonomic validity of Onchocerca gibsoni, O. gutturosa and O. lienalis. Furthermore, the diagnostic enzyme markers detected form the basis for identification of life-cycle stages, individuals and species and population structure analyses.

Animals↗
PubMed1989

Some simple statistical tests for exploring single-case time-series data.

Statistical analysis of single-case time-series data has received considerable attention. Many of the techniques discussed in the literature require long series of data or sophisticated statistical techniques. The present paper describes a number of 'quick and dirty' non-parametric tests which can be applied to relatively short time series. These tests require minimal calculations and can be carried out by inspecting graphical plots of the data. Each test is illustrated and tables for significance testing have been worked out. The importance of these tests lies in their potential to facilitate the accurate description of time series data. They are recommended as techniques for exploratory data analysis, the philosophy of which parallels Sidman's (1960) 'data led' approach to experimentation.

Adult↗
PubMed1989

A comparison of the toxicity and efficacy of cisplatin and carboplatin in advanced ovarian cancer. The Swons Gynaecological Cancer Group.

Eighty-eight patients with stage IIB-III epithelial ovarian cancer were randomised to receive first line single agent cisplatin (100 mg/m2) monthly or carboplatin (400 mg/m2) monthly for up to 5 cycles. Crossover to the opposite analogue occurred with progression or lack of response. All patients were premedicated with i.v. methylprednisolone (500 mg at 0 hours and 250 mg at 3 hours) and the first 20 patients in both groups received lorazepam and prochloperazine for nausea and vomiting. The median number of vomiting episodes per cycle with cisplatin was 16 and with carboplatin 2 (p less than 0.001). In the cisplatin arm 27/40 (67.5%) developed mild renal toxicity, 9/40 (22.5%) WHO grade I neurotoxicity and 18/40 (45%) evidence of ototoxicity at audiometry. To date we have seen no neuro- or ototoxicity with carboplatin and 1/40 (2.5%) have developed WHO grade I renal toxicity. Myelosuppression and anaemia was more common with carboplatin but only 1 episode of grade IV thrombocytopenia has been seen with first line carboplatin. The clinical response rate (CR+PR) for cisplatin was 19/40 and for carboplatin 27/40. Actuarial survival for cisplatin group at 24 months was 50% and for carboplatin group 58% with no significant difference. Carboplatin appears less toxic than cisplatin producing to date similar survival and response as a single agent.

Antiemetics↗
PubMed1989

Exposure of cryptantigens on red blood cell membranes in patients with acquired immune deficiency syndrome or AIDS-related complex.

Patients with acquired immune deficiency syndrome (AIDS) or AIDS-related complex (ARC) are subject to recurrent and severe infections due to organisms known to cause red blood cell membrane modifications. These red cell modifications include the exposure of novel carbohydrate cryptantigens that can react with naturally occurring antibodies and potentially result in hemolysis. We examined the frequency of cryptantigen exposure on the surface of red cells from AIDS/ARC patients. Blood samples from 108 patients with AIDS/ARC and from 65 non-AIDS/ARC patients were tested for most common forms of cryptantigens. The lectin Arachis hypogaea agglutinated red cells from 7% (8/108) of the AIDS/ARC patients and 3% (2/65) of non-AIDS/ARC patients, indicating the presence of T, Tk, or Th cryptantigen exposure. One sample from an AIDS patient with E. coli sepsis had T activation with polyagglutinable red cells. None of the samples showed evidence of exposed Tn or acquired B antigens. These results show that red cell cryptantigen exposure does occur in AIDS patients with a prevalence similar to that previously reported in patients with sepsis or malignancy. For this reason, and because polyagglutination has been associated with in vivo hemolysis, cryptantigen exposure should be considered in the differential diagnosis in AIDS patients with suspected immune hemolysis; it can be tested for by performing a minor crossmatch with ABO compatible serum.

ABO Blood-Group System↗
PubMed1988

Knee injuries in sports.

Many knee injuries that previously caused disability can now be diagnosed accurately and treated successfully. Arthroscopy has been instrumental in this progress. The anterior cruciate ligament, which is an important stabilizer of the knee, is commonly injured. Disruption of the restraint provided by the ligament results in an unstable knee that can give way during pivoting motions. Early reconstruction is usually effective in restoring stability and improving function. Considerable progress has been made in knee bracing. However, prophylactic bracing has not been demonstrated to be effective in preventing knee injuries.

Athletic Injuries↗
PubMed1988

Antigen CA125 in tumor tissue and serum from patients with adenocarcinoma of the ovary.

The presence of cancer antigen CA125 has been assessed immunohistologically in formalin-fixed tumor tissue and immunoradiometrically in serum from 41 women with residual epithelial ovarian carcinoma after diagnostic laparotomy. CA125 was detected in tumor tissue from the majority of patients (34/41), including those with normal serum levels (15/18). The major determinant of serum CA125 concentration appears to be the size of the residual tumor. The results suggest that in the majority of patients with small residual tumor masses and normal postoperative serum antigen levels, progressive disease may well be associated with increasing serum CA125 levels.

Adenocarcinoma↗
PubMed1988

Identification of life cycle stages of the nematode Echinocephalus overstreeti by allozyme electrophoresis.

Data presented in this study highlight the potential of allozyme electrophoresis in providing unequivocal genetic evidence for the identification of life cycle stages, particularly where species have complex life cycles. Adults of the nematode Echinocephalus overstreeti parasitize the elasmobranch Heterodontus portusjacksoni. The putative larval form which is morphologically dissimilar is found in two species of marine molluscs, Chlamys bifrons and Pecten albus. Electrophoretic analysis indicated that the adult and larval forms shared alleles at all of the 34 enzyme loci established. Furthermore, there were no fixed allelic differences between larval forms from different mollusc species.

Alleles↗
PubMed1988

Effect of forskolin and prostaglandin E1 on stimulus secretion coupling in cultured bovine adrenal chromaffin cells.

Treatment of adrenal chromaffin cells with forskolin (0.1-10 microM) stimulated cyclic AMP levels, reduced the maximal stimulation of release of noradrenaline by nicotine, and increased release in response to elevated external potassium and the calcium ionophore A23187. The presence of the phosphodiesterase inhibitor Ro 20-17-24 with forskolin potentiated both the stimulation of cyclic AMP and the inhibition of nicotine-induced noradrenaline release. Dibutyryl cyclic AMP, and the elevation of cyclic AMP with prostaglandin E1, also attenuated nicotine-stimulated release. However, when the stimulation of intracellular cyclic AMP production by prostaglandin E1 was potentiated by low levels of forskolin, there was not a concomitant potentiation of effect on noradrenaline release. Dideoxyforskolin, an analogue of forskolin which does not stimulate adenylate cyclase, inhibited both potassium- and nicotine-stimulated release, probably by a mechanism unrelated to the action of forskolin in these experiments. Using Fura-2 to estimate free intracellular calcium levels, both forskolin and dideoxyforskolin (at 10 microM) reduced the calcium transient in response to nicotine. These results support a model in which elevation of cyclic AMP inhibits the activation of nicotinic receptors, but augments stimulus secretion coupling downstream of calcium entry. The data, however, do not indicate a simple relationship between total intracellular cyclic AMP levels and the attenuation of nicotinic stimulation of release.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed1988

Effects on respiratory pattern of focal cooling in the medulla of the dog.

Studies in cats have shown that, in addition to respiratory neuron groups in the dorsomedial (DRG) and ventrolateral (VRG) medulla, neural structures in the most ventral medullary regions are important for the maintenance of respiratory rhythm. The purpose of this study was to determine whether a similar superficially located ventral region was present in the dog and to assess the role of each of the other regions in the canine medulla important in the control of breathing, in 20 anesthetized, vagotomized, and artificially ventilated dogs, a cryoprobe was used to cool selected regions of the medulla to 15-20 degrees C. Respiratory output was determined from phrenic nerve or diaphragm electrical activity. Cooling in or near the nucleus of the solitary tract altered timing and produced little change in the amplitude or rate of rise of inspiratory activity; lengthening of inspiratory time was the most common timing effect observed. Cooling in ventrolateral regions affected the amplitude and rate of rise of respiratory activity. Depression of neural tidal volume and apnea could be produced by unilateral cooling in two ventrolateral regions: 1) near the nucleus ambiguus and nucleus para-ambiguus and 2) just beneath the ventral medullary surface. These findings indicate that in the dog dorsomedial neural structures influence respiratory timing, whereas more ventral structures are important to respiratory drive.

Animals↗
PubMed1987

Stimulus secretion coupling in cultured chromaffin cells. Dependency on external sodium and on dihydropyridine-sensitive calcium channels.

Stimulus secretion in response to acetylcholine (or nicotine) in adrenal chromaffin cells involves calcium influx and is tetrodotoxin insensitive. The mechanism by which activation of the nicotinic acetylcholine receptor (AChR) leads to calcium influx is not clear, and the requirement for external sodium is controversial. We report that when bovine chromaffin cells are continuously perfused in the absence of sodium, secretion of catecholamines in response to 3 X 10(-5) M nicotine is not impaired. Also, secretion stimulated by this concentration of nicotine is not potently and stereospecifically inhibited by the (+)- and (-)-isomers of nicardipine. At a concentration of (+)-nicardipine (10(-7) M) which inhibits most of the release stimulated by 50 mM potassium, the response to 3 X 10(-5) M nicotine remains; however, the dose-response curve to nicotine is shifted slightly to the left. The results are discussed with respect to models of stimulus secretion coupling in bovine adrenal chromaffin cells.

Acetylcholine↗
PubMed1987

Whipple's disease confined to the central nervous system.

Progressive hypersomnia, memory disturbance, and vertical ophthalmoplegia developed in a 63-year-old woman. The diagnosis of Whipple's disease of the central nervous system was suggested by her presentation and results of studies using magnetic resonance imaging. Despite a one-month course of antibiotics, active Whipple's disease, localized to the central nervous system, was found at autopsy.

Anti-Infective Agents↗