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Biomedical subjects

J Curtis

Publications and source records attributed to J Curtis.

At least 163 records · Page 9Linked to original sources

The influence of morphology on prognosis in acute leukemia.

The presence of definite cytoplasmic granulation in at least some of the malignant cells was used as the sole criterion to separate 156 patients with acute leukemia into two groups: 110 with myeloblastic (AML), and 46 with lymphoblastic or stem cell leukemia (ALL). The median survival from the onset of symptoms in patients with AML was 20 weeks, and those with ALL 37 weeks. The difference in survival in these two groups is much greater for patients under the age of 25 than for those over the age of 25.

Adolescent↗

Extraction of corticosterone from cell homogenates and subcellular fractions of the rat adrenal cortex. III. ACTH-induced temporal subcellular redistributions of steroid precursors to corticosterone.

Cholesterol, pregnenolone, progesterone, 11-deoxycorticosterone (11-DOC) and corticosterone were quantitated in subcellular fractions isolated from in vivo adrenocorticotropin (ACTH)-stimulated rat adrenal zona fasciculata/reticularis. Six adrenal subcellular fractions separated by discontinuous sucrose gradient centrifugation (lipid, 0.125 M sucrose, cytosolic, microsomal, mitochondrial and nuclear) were extracted with alkaline ether/ethanol and assayed by high pressure liquid chromatography (HPLC). Lipid fractions contained the major cholesterol stores, while most pregnenolone and progesterone was found in lipid, microsomal and mitochondrial fractions. The 0.125 M sucrose and cytosol fractions together contained approximately 75% of the total 11-DOC and corticosterone. The five steroids were only present in small amounts in organelle fractions containing steroidogenic enzymes. Homogenate and lipid fraction cholesterol decreased between 10 and 15 min and again 30 min after ACTH injection. In the homogenate, lipid, microsomal and mitochondrial fractions, pregnenolone and progesterone were increased after ACTH injection; peak pregnenolone and progesterone concentrations were often measured in adrenal gland sucrose, cytosolic, microsomal and mitochondrial fractions 15 to 20 min after rats were injected with ACTH. Although ACTH increased 11-DOC and corticosterone in all but the mitochondrial and nuclear fractions, the sucrose, cytosolic and microsomal 11-DOC, and cytosolic corticosterone increased most dramatically. In many fractions, peak 11-DOC and corticosterone concentrations were most often observed between the 10 and 15 min periods and again at 30 min.

Adrenal Cortex↗

Is early separation anxiety a risk factor for adult panic disorder?: a critical review.

Heightened levels of early separation anxiety (SA) have long been linked to the risk of adult panic disorder (PD), suggesting that the two types of anxiety arise from a common diathesis--a proposition that has considerably influenced the classification of the anxiety disorders. However, the SA-PD link remains contentious, with some recent studies failing to confirm that putative association. All published research studies investigating the relationship of early SA to PD and/or other anxiety disorders were reviewed. Taken as a whole, the evidence provides support for the SA-PD hypothesis, although the specificity of that relationship needs further clarification. Problems of sample selection, retrospective measurement of early SA and comorbid diagnoses limit the certainty with which inferences can be drawn from existing data. Nevertheless, a recent community-based study provides additional support for the SA-PD hypothesis. Possible developmental pathways linking SA to PD are considered. One possibility that has not received adequate research attention is that early SA disorder (SAD) may persist into adulthood, rendering the sufferer vulnerable to panic and other anxiety symptoms when confronted with salient life stressors. We conclude that it is premature to reject the SA hypothesis of PD. Only well-designed longitudinal studies can map the complex developmental pathways linking early and later manifestations of morbid anxiety.

Adolescent↗

Separation anxiety in adulthood: a phenomenological investigation.

Separation anxiety disorder is well recognized as a juvenile psychiatric disorder, but it appears to be rarely diagnosed in adulthood. Drawing on our clinical impressions and a review of the relevant literature, we sought to investigate whether separation anxiety symptoms could be identified in adulthood. Forty-four subjects recruited by a media campaign were administered a semistructured interview and a self-report checklist for adult separation anxiety (ASA) symptoms, as well as the Separation Anxiety Symptom Inventory (SASI), a retrospective measure of early separation anxiety symptoms. Diagnoses of major depressive disorder (MDD), panic disorder (PD), agoraphobia (Ag), and dependent personality disorder were made using the SCID-P and SCID-II. Thirty-six subjects met criteria for a putative diagnosis of ASA based on a global clinical rating and/or endorsement of DSM-IV-derived criteria. Although most subjects dated the separation anxiety symptoms to their juvenile years, it was notable that one third reported the first onset of separation anxiety symptoms in adulthood. Although comorbid lifetime anxiety or depressive disorders were common, the majority of subjects reported that the separation anxiety symptoms predated other axis I disorders. Only six subjects (17%) were diagnosed with dependent personality disorder. Although limited by the method of sampling, this preliminary study suggests the need to examine more systematically whether a form of separation anxiety disorder may occur in adulthood.

Adult↗

A trial of proguanil-dapsone in comparison with sulfadoxine-pyrimethamine for the clearance of Plasmodium falciparum infections in Tanzania.

Considerable levels of resistance to sulfadoxine-pyrimethamine (SP) have been reported in Plasmodium falciparum in north-eastern Tanzania, and the identification of a suitable antimalarial to replace SP is now a high priority. We conducted a trial in July 2000 to determine the efficacy of proguanil (PG) plus dapsone (DS), compared with that of SP, for the treatment of asymptomatic falciparum infection. A total of 220 children with parasitaemia > or = 2000 per microL completed the study; 112 had received a single dose of SP (dosage calculated for pyrimethamine 1.25 mg/kg and sulfadoxine 25 mg/kg) and 108 had taken PG 10 mg/kg with DS 2.5 mg/kg each day for 3 days. Clearance of asexual parasites at day 7 was 14.3% with SP, but 93.5% with PG-DS. The remarkably high failure rate with SP was not associated with occurrence of leucine substitution at position 164 of the dhfr gene. Both treatment regimens were well tolerated. Compared with available data on another antifolate combination, chlorproguanil-dapsone ('Lapdap'), PG-DS was slightly but significantly inferior in achieving parasite clearance (99.5% versus 93.5%). The estimated cost of a 3-day course of PG-DS treatment for a child weighing 18 kg is US $0.15. With the rising incidence of SP-resistant P. falciparum infection, PG-DS could provide an effective, affordable and already available therapeutic alternative for malaria in East Africa at least until chlorproguanil-dapsone is registered.

Antimalarials↗

Direct evidence that asparagine at position 108 of the Plasmodium falciparum dihydrofolate reductase is involved in resistance to antifolate drugs in Tanzania.

A nested polymerase chain reaction was used to amplify a fragment of the gene for dihydrofolate reductase of Plasmodium falciparum containing codon 108, where a point mutation, causing a serine to asparagine change, occurs in pyrimethamine resistant parasites. The presence of the mutation was detected by restriction enzyme digestion. Parasites in blood samples collected from asymptomatic children before, and 3 weeks after, treatment with pyrimethamine-sulfadoxine or chlorproguanil-dapsone were analysed. Parasites in the samples taken at 3 weeks carried only the asparagine mutant.

Animals↗

Continuities of separation anxiety from early life into adulthood.

The study investigates whether a putative diagnosis of separation anxiety disorder can be identified in adulthood and whether there are continuities between juvenile and adult forms of the disorder. Seventy patients with conventional adult diagnoses of panic disorder and generalized anxiety disorder attending an anxiety clinic were administered an interview and checklist to assess separation anxiety (SA) symptoms in adulthood. Memories of early SA were assessed using the Separation Anxiety Symptom Inventory (SASI). A subsample (n = 31) was used to calibrate the checklist against assignment to a category of adult separation anxiety disorder (ASAD) based on the structured interview. In an expanded sample (n = 70), patients assigned to the ASAD category returned statistically higher scores on the SASI, with the severity of juvenile SA symptoms accounting for 33% of the variance of adult SA scores (p < .001). Assignment of subjects to the putative ASAD category was not associated with any conventional adult anxiety diagnosis and symptoms of SA appeared to predate the onset of the other anxiety disorders. One possible explanation for the data is that, in some individuals, early onset separation anxiety disorder may persist into adulthood, but the symptoms may either be overlooked or, alternatively, obscured by secondary features such as panic.

Adolescent↗

Widespread heteroplasmy in schistosomes makes an mtVNTR marker "nearsighted".

Mitochondrial markers are often hailed as the preferred DNA elements for analyses of population subdivision. To this end we have employed a mitochondrial repeat element to examine the population structure in Schistosoma mansoni (human blood flukes). Schistosome isolates were collected from each of 21 different patients representing seven different areas of a Brazilian village. These parasite isolates demonstrate substantial genetic polymorphism, with an average of 10 genotypes infecting each patient, which is more readily detected because of high levels of heteroplasmy (i.e., 72.5% of the individual worms exhibit multiple versions of this repeat region with different numbers of repeats). Due to the high number of common haplotypes in the population, this repeat element from S. mansoni has a large proportion (47%) of its genetic variation described by differences among mitochondrial genomes within individual worms. However, when only rare haplotypes are considered, population structure can be detected. It seems that heteroplasmy in the schistosome population of Melquiades is both the source of plentiful genetic variation and a confounding factor in the analysis of that variation. Thus the schistosome population in Melquiades may actually be more strongly subdivided than we are able to detect using this mitochondrial marker.

Animals↗