Is human cryptosporidiosis a zoonotic disease?
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Animals↗
Biomedical subjects
D Evans
Publications and source records attributed to D Evans.
DNA B facilitates, but is not essential for, the spread of abutilon mosaic virus in agroinoculated Nicotiana benthamiana.
Full-length dimers of both DNA A and DNA B of Abutilon mosaic virus have been constructed. These constructs are not infectious when inoculated into Nicotiana benthamiana as DNA; however, an infection could be obtained using the method of agroinoculation. Symptom induction required both DNA molecules but agroinoculation with DNA A alone resulted in virus spread in the majority of plants. Mutations were made in both of the open reading frames of DNA B. Coagroinoculation of wild-type DNA A and mutant B showed that DNA B is necessary for a full infection and symptom induction. Furthermore, it was shown that mutations in DNA B inhibit the ability of DNA A to spread independently. A normal infection was obtained following coagroinoculation of both DNA B mutants and wild-type DNA A. PCR analysis of DNA extracted from these plants showed that the infection was brought about by complementation rather than recombination.
Biological Transport↗
Complementation and recombination between mutants of complementary sense genes of DNA A of Abutilon mosaic virus.
Mutations have been inserted into the complementary sense ORFs of DNA A of Abutilon mosaic virus (AbMV). Mutation in both ORF AC1 and ORF AC2/3 resulted in clones incapable of infecting Nicotiana benthamiana following agroinoculation. Mutation in ORF AC1 but not in ORF AC2/3 prevented DNA replication in leaf discs. Thus ORF AC1 is essential for AbMV DNA replication whereas ORF AC2/3 is probably involved in some aspect of the spread of the virus through the plant. Coagroinoculation of both mutants and wild-type DNA B resulted in complementation and recombination. Complementation precedes recombination and once recombination is established mutant DNA can no longer be detected. Plants in which complementation alone is occurring are symptomless and contain relatively low amounts of virus double-stranded DNA whereas following recombination a wild-type infection is established.
Blotting, Southern↗
Community service utilization by youths hospitalized in a state psychiatric facility.
A majority of a cohort of 62 children and adolescents who had been hospitalized in a state psychiatric facility was found to have received less restrictive services such as outpatient mental health services prior to their index admission. Also, a number had been involved with the juvenile justice system and almost two-thirds had been placed out-of-home. Ninety percent had at least one prior psychiatric hospitalization. Just over half of the cohort received case management and individual counseling post release. About a third received family counseling, and a few received other types of services. At least a third were rehospitalized within a year of release. Although 90% of the cohort received some type of service post release, a higher proportion of non service receivers were rehospitalized than service receivers. Even those who received services had a high rate of rehospitalization. These findings raise questions as to the appropriateness of service provision during and following hospitalization.
Adolescent↗
Characterization and primary structure of a human immunodeficiency virus type 1 (HIV-1) neutralization domain as presented by a poliovirus type 1/HIV-1 chimera.
The poliovirus/human immunodeficiency virus (HIV) chimera S1/env/3 presents the sequence DRPEGIEEEGGERDRDRS, a known glycoprotein gp41 neutralizing domain (residues 735 to 752) of HIV IIIB in an antigenic site of the Sabin type 1 strain of poliovirus. Of 10 monoclonal antibodies raised against the sequence as presented in S1/env/3, eight were shown to neutralize HIV IIIB in vitro whereas all 10 neutralized S1/env/3, suggesting that the presentation of the sequence is comparable between HIV and the poliovirus/HIV chimera. The monoclonal antibodies were characterized by the selection of escape mutants from S1/env/3 and by Pepscan analysis. The two methods gave similar results, identifying two epitopes involving amino acids corresponding to residues 740 to 743, and to residues 745 to 750 of gp41. Mutations selected in the chimera with S1/env/3-specific MAbs are identical or similar to changes occurring in vivo in natural isolates of HIV-1. This finding suggests that the epitope may be significant in the neutralization of HIV in vivo.
Amino Acid Sequence↗
Cultural lag, economic scarcity, and the technological quagmire of "Infant Doe".
The major purpose of this article is to explore the substantial disparity between access to resources provided at birth to a child with spina bifida--a so-called Baby Doe--and later access to resources needed to sustain that child throughout the life course. The author's organizing principle is the allocative paradoxes created by the clash of technology, scarcity, and demography. The study is based on an eight-year inquiry into the way life-saving medical decisions are made about children with spina bifida. This work focuses on the qualitative aspects of that inquiry. There is a societal need to debate health care rationing, to do much more systematic technology assessment, and to develop a much more consistently rational system of health care delivery.
Adult↗
Food stimulation of histidine decarboxylase messenger RNA abundance in rat gastric fundus.
1. Histidine decarboxylase in the enterochromaffin-like cells of the gastric corpus mucosa converts histidine to histamine which in turn stimulates gastric acid secretion. The control of histidine decarboxylase activity is poorly understood. We have examined how fasting and refeeding influence the abundance of the messenger RNA encoding histidine decarboxylase in the gastric corpus of the rat. 2. The polymerase chain reaction was used to generate a probe for detection of histidine decarboxylase messenger RNA in Northern and slot blots of total RNA from the gastric corpus of rats fasted for up to 48 h, or fasted and then refed. A gastrin monoclonal antibody was used to neutralize the action of endogenous gastrin. 3. Fasting progressively reduced histidine decarboxylase messenger RNA abundance by 3- to 4-fold after 48 h. Refeeding induced a rapid increase in histidine decarboxylase messenger RNA abundance which was detectable after 30 min. 4. There was a significant correlation between histidine decarboxylase messenger RNA abundance and plasma gastrin. Administration of gastrin antibody inhibited the increase in histidine decarboxylase activity after 6 h refeeding, but not after refeeding for 30 min. 5. The results suggest that histamine-mediated changes in postprandial acid secretion depend on control of histidine decarboxylase mRNA levels, and that gastrin regulates production of this enzyme in the rat over periods of a few hours.
Animals↗
Paediatric gastro-oesophageal reflux: prognostic indicators from pH monitoring.
The original diagnostic 24 hour pH monitoring data in 57 children with gastro-oesophageal reflux (GOR) were retrospectively reviewed after a minimum of one year follow up. The tracings of children who responded to medical treatment were compared with those who failed to respond and required a fundoplication. Children with GOR secondary to oesophageal atresia/tracheo-oesophageal fistula and neurological conditions (n = 12) were analysed separately from those with primary GOR (n = 45). Children with primary GOR requiring a fundoplication (n = 9) had increased daytime reflux. The percentage time pH < 4 was the best discriminator (21% v 7%) with a threshold of 18% giving a 92% specificity and a 70% sensitivity. For children with secondary GOR the percentage time pH < 4 at night was significantly higher (29% v 3.7%) in those requiring a fundoplication (n = 5). A threshold of 18% gave an 80% specificity and an 86% sensitivity. These results show that both daytime and night time pH monitoring data can be of prognostic value in different subgroups of children with GOR. A percentage time pH < 4 of greater than 18% was a useful threshold to apply when evaluating the pH monitoring data.
Child, Preschool↗
To help patients control asthma the clinician must be a good listener and teacher.
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Adult↗
Control of gastric corpus chromogranin A messenger RNA abundance in the rat.
Enterochromaffin-like cells in the corpus mucosa of the stomach produce histamine in response to gastrin; chromogranin A (CGA) is often used as a morphological marker for these cells, but its functional significance in the gastric mucosa is largely unknown. We have examined whether CGA mRNA abundance in the rat corpus is controlled by endogenous gastrin. In rats fasted for up to 48 h, there was a progressive decline in plasma gastrin and CGA mRNA; refeeding of fasted rats produced a prompt increase in plasma gastrin and an increase in CGA mRNA that was significant after 4 h. Treatment of fasted rats with omeprazole to inhibit acid secretion increased plasma gastrin and CGA mRNA levels. The increased CGA mRNA associated with omeprazole or refeeding was reversed by treatment of rats with the gastrin/cholecystokinin B antagonist CI-988 and gastrin antibody, respectively. The results suggest that CGA production in enterochromaffin-like cells of the rat stomach is part of the functional response of these cells to circulating gastrin.
Animals↗
Gastrin cell responses to acidification of the achlorhydric rat stomach.
In the rat, gastrin cells are normally exposed to the stimulatory effects of food and the inhibitory influences of acid in the gastric lumen. We have studied the effects of intragastric acid on gastrin cell function in animals in which the tonic inhibitory action of acid was removed by prior treatment with the proton pump blocker omeprazole. In fasted rats with gastric fistula treated with omeprazole, instillation of acid into the stomach produced a prompt decrease in plasma gastrin, but gastrin mRNA abundance showed a modest transient increase over a period of 2 h and thereafter no change; there was also a transient increase in tissue concentrations of the gastrin precursor progastrin that was compatible with increased gastrin synthesis. Concentrations of tissue gastrins, in general, increased after acid instillation, which can be attributed to continued synthesis in the presence of suppressed gastrin release. In rats fed ad libitum, a single dose of omeprazole (which produces achlorhydria for 24-30 h) produced an increase in plasma gastrin that peaked after 24 h and declined to control levels over the following 48 h; in contrast, gastrin mRNA abundance peaked 48 h after omeprazole before declining to control levels. The results indicate that whereas gastrin release might be promptly inhibited by intragastric acid, the changes in gastrin mRNA abundance are much slower: achlorhydria increases gastrin mRNA within 24 h, but acid takes longer to depress gastrin mRNA abundance. Over periods of a few hours, gastrin release and synthesis need not, therefore, change in parallel.
Animals↗
Differential control of somatostatin messenger RNA in rat gastric corpus and antrum. Role of acid, food, and capsaicin-sensitive afferent neurons.
Somatostatin messenger RNA in the antrum and corpus of rat stomach was quantified by Northern and slot blotting using a probe generated by the polymerase chain reaction. Fasting for 48 h enhanced the abundance of somatostatin mRNA in the pyloric antral region, but not in the acid-secreting region of the stomach. In fasted rats, somatostatin mRNA in antrum, but not corpus, was decreased by inhibition of acid secretion with omeprazole. In contrast, in rats treated with capsaicin to lesion small diameter afferents there was a significant decrease in somatostatin mRNA abundance in the corpus but not antrum. The effects of capsaicin cannot be attributed to nonspecific changes in gastric endocrine cell gene expression, since the abundance of histidine decarboxylase mRNA (which is a functionally regulated marker for a different gastric endocrine cell type) did not change with capsaicin. Gastric capsaicin-sensitive afferents are rich in calcitonin gene-related peptide, and in rats with antibodies to this peptide there was reduced corpus somatostatin mRNA. Moreover, infusion of calcitonin gene-related peptide in control rats produced a significant increase in somatostatin mRNA in the gastric corpus. The results indicate that somatostatin mRNA abundance is controlled by the gastric luminal contents and the extrinsic afferent innervation, but the relative importance of these factors differs in antrum and corpus: luminal contents are relatively more important in antrum and primary afferents using calcitonin gene-related peptide in the corpus.
Actins↗
Impact asymptomatic HIV-1 infection on renal allograft recipients.
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Acquired Immunodeficiency Syndrome↗
Urate-null rosy mutants of Drosophila melanogaster are hypersensitive to oxygen stress.
It has been proposed that uric acid is an important scavenger of deleterious oxygen radicals in biological systems [Ames, B. N., Cathcart, R., Schwiers, E. & Hochstein, P. (1981) Proc. Natl. Acad. Sci. USA 78, 6858-6852]. We report here an in vivo investigation of the oxygen defense role of uric acid through an analysis of mutants of the rosy (ry) gene of Drosophila melanogaster. The ry gene is the structural gene for the molybdoenzyme, xanthine dehydrogenase; xanthine dehydrogenase-null ry mutants are therefore unable to synthesize urate. The rationale of our approach was to measure the response of urate-null ry mutants to extraordinary oxygen stress as imposed by exposure to radical-generating agents and as conferred by a genetic defect in superoxide dismutase, an established oxygen defense function. We show that urate-null mutants of the ry locus are hypersensitive to paraquat, ionizing radiation, and hyperoxia. Furthermore, compound mutants doubly deficient for uric acid and Cu/Zn-containing superoxide dismutase are synthetic lethals, which are unable to complete metamorphosis under normal growth conditions. These experiments demonstrate unambiguously the importance of urate in oxygen defense in vivo and support our earlier proposal that the molybdoenzyme genetic system plays a critical role in oxygen defense in Drosophila. They also form the basis for our proposal that metamorphosis in Drosophila imposes a crisis of oxygen stress on the developing imago against which uric acid plays an important organ-specific defense. Finally, the results provide a basis for understanding the syndrome of phenotypes, including the hallmark dull brown eye color, which characterizes mutants of this classic genetic system of Drosophila.
Animals↗
Service needs of youths released from a state psychiatric facility as perceived by service providers and families.
The following article reports on the results of service needs assessments of a cohort of youths released from a state psychiatric facility as perceived by service providers and families/caregivers. Families as well as service providers consistently agreed on three service areas of high need--psychotherapy for the child, family therapy and parent skill training. However, families perceived a need for a number of other services that are not traditionally provided by the mental health system such as after school recreation activities and self-help and support groups for the child. The discrepancies between service providers and families' perceptions of assessed needs may lead to families dropping out of service due to the unresponsiveness of the services in meeting their perceived needs. Steps that service providers need to take to be more responsive to the needs of families are discussed.
Adolescent↗
Assessment of therapeutic relationship of community-agency workers.
This article reports on the ratings of the personal and professional characteristics of community-based workers for children and adolescents who had recently been released from a psychiatric inpatient service. The child/adolescent's family members/caregivers and the community workers both responded to the same items of a questionnaire. Families/caregivers rated the community workers with whom they were the most and the least satisfied. Community workers rated themselves in relation to these study children and/or their families. Findings indicate that both family members/caregivers and the community workers themselves saw community workers performing relatively well in the areas of providing information and offering support to families. Likewise, both assessed the service providers as having the greatest deficits in the area of teaching skills for child/adolescent home management. Suggestions for meeting the needs of the families and for ensuring that a system of care for child/adolescents is child-centered and family-focused are discussed.
Adolescent↗
Economic considerations for helminth control.
The economic literature related to the control of helminths has grappled with three inter-related questions: is the control of helminths a priority health issue at a time of increasing resource scarcity, are any of the available options affordable and what is the most cost-effective control strategy? In this review of the recent literature, Helen Guyatt and David Evans reveal that the attempts to answer these questions have not been entirely successful, partly because they have sometimes focused on inappropriate issues and partly because some of the potentially valuable economic techniques are still being developed. However, the major current impediment to the provision of satisfactory answers is the lack of precise detail about the nature of the morbidity associated with helminth infections.
Journal Article↗