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Biomedical subjects

J Hicks

Publications and source records attributed to J Hicks.

At least 37 records · Page 2Linked to original sources
PubMed2000

Magnetic resonance imaging detection of occult skin and subcutaneous abnormalities in juvenile dermatomyositis. Implications for diagnosis and therapy.

OBJECTIVE: To assess the utility of magnetic resonance imaging (MRI) of skin, subcutaneous tissue, and fascia in evaluating disease activity in juvenile dermatomyositis (DM). METHODS: Short tau inversion recovery (STIR) MRI of the proximal thighs and buttocks, cutaneous assessment, and other measures of disease activity were prospectively obtained in 26 children meeting criteria for probable or definite juvenile DM. Also undergoing STIR MRI assessment were 8 subjects who were being evaluated for muscle disorders and who were not diagnosed as having juvenile DM. RESULTS: Skin, subcutaneous, or fascial edema of the thighs and buttocks were seen on STIR MRI in up to 85% of juvenile DM patients at baseline evaluation compared with no more than 38% of the comparison group without juvenile DM. In juvenile DM, STIR MRI skin and subcutaneous edema scores correlated (r(s) = 0.51, P = 0.008), as did fascial and muscle edema scores (r(s) = 0.58, P = 0.002). Skin global disease activity scores correlated with MRI skin edema scores (r(s) = 0.41, P = 0.04), and serum aldolase levels correlated with both MRI skin and subcutaneous edema scores (r = 0.44 and 0.40, P = 0.03 and 0.05 respectively). The extent and severity of STIR MRI changes in the skin, subcutaneous tissue, and fascia were not predicted by most other measures of juvenile DM disease activity. Five juvenile DM patients with thigh MRI subcutaneous edema developed clinically apparent calcinosis at the same location within 9 months. CONCLUSION: Edema or inflammation in the skin, subcutaneous tissue, and fascia, found on STIR MRI, is common in juvenile DM patients and is often undetected by standard assessments. These MRI changes can precede the development of calcinosis. STIR MRI may be a useful adjunct for assessing disease activity and guiding the treatment of juvenile DM.

Adolescent↗
PubMed2000

Mucoepidermoid carcinoma of salivary glands in children and adolescents: assessment of proliferation markers.

Malignant neoplasms represent one-third of all pediatric salivary gland tumors. Mucoepidermoid carcinoma (MEC) composes 51% of malignant tumors and 16% of all salivary gland neoplasms in pediatrics. Prognostic factors in MEC in pediatric patients have not been well defined. Histopathologic features, clinical outcomes and proliferation markers in 26 pediatric patients (median age 11 years; 19F:7M) with salivary gland MECs were evaluated retrospectively. MEC histocytologic grading used a three-tiered system. Proliferation was assessed by determining the percentage of tumor cells immunoreactive for PCNA and Ki-67. Tumor site was 16 parotid, eight submandibular, one base of tongue and one maxillary lip. Median tumor size was 2.5 cm (range 1.5-5 cm). MEC grade was nine low grade (LG), 15 intermediate grade (IG) and two high grade (HG). Metastatic disease and capsular invasion occurred in five cases, while perineural invasion was noted in three cases. Mean percentage of tumor cells immunoreactive for proliferation markers is as follows: PCNA: LG 9%, IG 17%, HG 32%; and Ki-67: LG 7%, IG 12%, HG 26%. Treatment was surgical in 21 cases, and surgery with chemotherapy and radiotherapy in five cases. Two patients with high grade MECs died of disease (21, 44 months). Twenty-four patients had no evidence of disease at a median follow-up of 104 months (range 30-298 months). MECs were second malignancies in two children with prior radiotherapy and chemotherapy for leukemia and histiocytosis. Low and intermediate grade salivary gland MECS in a pediatric population may have a favorable outcome when compared with high grade MECs. Proliferation markers appear to be linked to histocytologic MEC grade and may provide information regarding biologic behavior of salivary gland MECs in children and adolescents.

Adolescent↗
PubMed2000

Investigation of amine and polyol functionality in extracts of polyurethane wound management dressings using MALDI-MS.

Polyurethane (PU) foams used in wound management are produced by a reaction between aromatic diisocyanates and polyether polyols. There is concern that residues of these starting materials, which may contain aromatic amine functionality, may leach from the finished polymer during in vivo applications. Furthermore, oligomers and additives may be leached from the PU system after the polymerization process is complete. Finished polymers have, therefore, been extracted with a range of solvents, such as water, diethyl ether and dilute HCl. The extracts were subjected to MALDI-MS (matrix-assisted laser desorption ionization mass spectrometry) analysis in an attempt to determine the amine and polyol functionality. Direct MALDI-MS analysis of the wound dressing extracts indicated the presence of components based on the polyols [corrected] used in the formulation of the foam. The spacing between the peaks identified the base monomer used in the polyol. MALDI-MS analysis of the fluorescamine derivatives of model amine compounds has demonstrated the anticipated increase in mass (278 for monoamines and 278 and 556 for diamines). Similar results were obtained from the derivatization of model polyols with phenyl isocyanate, where the mass shift (n x 119) was a direct measure of the number of active hydroxyl groups. Fluorescamine labelling of PU foams shows the colour change which could be [corrected] indicative of the presence of an amine, but the subsequent MALDI-MS analysis was unable to demonstrate the anticipated increase in mass.

Amines↗
PubMed2000

G-protein signalling mediates differential production of toxic secondary metabolites.

Filamentous fungi elaborate a complex array of secondary metabolites, including antibiotics and mycotoxins. As many of these compounds pose significant economic and health concerns, elucidation of the underlying cellular mechanisms that control their production is essential. Previous work revealed that synthesis of the carcinogenic mycotoxins sterigmatocystin (ST) and aflatoxin (AF) in Aspergillus species is negatively controlled by FadA, the alpha-subunit of a heterotrimeric G-protein. In sharp contrast, we show here that the dominant activating fadA allele, fadAG42R, stimulates transcription of a gene from the A. nidulans penicillin (PN) gene cluster and elevates penicillin production. Thus, FadA has opposite roles in regulating the biosynthesis of a potent antibiotic (PN) and a lethal mycotoxin (ST) in A. nidulans. Furthermore, expression of fadAG42R in Fusarium sporotrichioides increases trichothecene (TR) mycotoxin production and alters TR gene expression. Our findings reveal that a G-protein defines an important control point for differential expression of fungal secondary metabolites within and across fungal genera. These data provide critical evidence suggesting that targeting G-protein signal transduction pathways as a means of controlling or preventing the production of a single mycotoxin could have serious undesirable consequences with regard to the production of other secondary metabolites.

Aspergillus nidulans↗
PubMed2000

High blood pressure and the kidney: the forgotten contribution of William Senhouse Kirkes.

The realization of the key role for raised intra-arterial pressure as a pathogenetic agent in hypertension is usually credited to Ludwig Traube, but Traube in his writings gives credit for the idea to a little-known English doctor, William Senhouse Kirkes (1822-1864). Kirkes' main interest was in cardiology and vascular disease, and he gave the first account of embolism from vegetations in infective endocarditis in 1852. Three years later, he published a study of apoplexy in Bright's disease, in which he pointed clearly to the role of raised intra-arterial tension in the causation of arterial disease, a point that had eluded Bright, Johnson, and other contemporaries. Kirkes died at the age of only 42 while working on a book summarizing his work on cardiology and renal disease, and the neglect of his contribution probably resulted from his early death. We have traced his life history from the few available records; as a boy, Kirkes was apprenticed to become a surgeon and only later trained as a physician. We place his contributions within the setting of the development during the 19th century of understanding of the relationship between the kidney, vascular disease, and high blood pressure.

Cardiomegaly↗
PubMed2000

Helicobacter pylori infection in children of Texas.

BACKGROUND: Acquisition of the Helicobacter pylori infection usually occurs in childhood. The prevalence of infection differs among ethnic groups and in adults is inversely related to the socioeconomic status of the individual's family during childhood. This study investigates the seroprevalence of H. pylori infection in children of different ethnic groups in relation to socioeconomic class and investigates the prevalence of acute H. pylori infection among children who have had recent onset of abdominal pain. METHODS: Serum samples were collected from 797 children, aged 6 months to 18 years, of various socioeconomic and ethnic backgrounds, at a large urban children's hospital. H. pylori status was determined by an anti-H. pylori immunoglobulin (Ig)G enzyme-linked immunosorbent assay (ELISA) validated for pediatric use. To determine the prevalence of acute H. pylori infection, children brought to the emergency center with abdominal symptoms without diarrhea and overt signs of acute abdomen were evaluated with both serology and the 13C-urea breath test. Acute H. pylori was defined as a positive 13C-urea breath test result and negative IgG serology for H. pylori. RESULTS: The overall seroprevalence of H. pylori was 12.2% and increased with age (e.g., 8.3% at 6-11.9 months and 17.9% at 13 years). The prevalence was inversely related to socioeconomic status (6.6%, moderate to high vs. 15%, low socioeconomic status). The difference in seroprevalence among blacks (16.8%), Hispanics (13.3%), and whites (8.3%; P < 0.01) could be accounted for by differences in socioeconomic status. Eighteen percent of children who were evaluated at the emergency center for recent-onset abdominal pain had acute H. pylori infections. CONCLUSIONS: Socioeconomic status, not ethnic group, is the more important risk factor for acquisition of H. pylori infection during childhood. Acute H. pylori infection was a relatively common cause of recent-onset, nonsurgical abdominal pain.

Abdominal Pain↗
PubMed2000

A CAT-derived one to three session intervention for repeated deliberate self-harm: a description of the model and initial experience of trainee psychiatrists in using it.

We describe a new Cognitive Analytic Therapy (CAT)-based intervention for those who repeatedly self-harm. It is specifically designed to be deliverable by staff with no training in psychotherapy. The intervention is simply manualized into sequential tasks that are mediated by new CAT-style standardized tools. A particular feature of this intervention is the deliberate use of feelings elicited in the therapist ('counter-transference') as (a) a guide to how professional poise is being threatened or lost and (b) an indicator of the appropriate focus for this very brief therapy. The psychiatrists' reflection on their elicited feelings is mediated by a new CAT tool, the 'Assessor's Response File' developed in this project. Audiotape analysis suggested that following a very brief learning period, trainee psychiatrists were able to adhere to the structure of the model and arrive at an appropriate reformulation in the first session but tended to be collusive in reciprocating the patients' dysfunctional coping styles.

Adaptation, Psychological↗
PubMed2000

Compomer materials and secondary caries formation.

PURPOSE: To evaluate the role of compomers in secondary caries formation in vitro. MATERIALS AND METHODS: 36 human teeth with caries-free enamel (coronal) and root surfaces underwent a fluoride-free prophylaxis. Class V cavities were prepared in buccal and lingual coronal and root surfaces. The teeth were divided into two groups with 3 treatment subdivisions [12 teeth per restorative material (6 with coronal restorations and 6 with root surface restorations)]). The preparations were restored with: (1) filled composite (Filtek Z250 with Single Bond), (2) fluoride-releasing compomer [Hytac with Prompt L-Pop (fluoride-releasing water-based adhesive)]; or (3) fluoride-releasing compomer [Dyract AP with Prime & Bond NT (fluoride-releasing acetone-based adhesive)]. 24 cavities (6 teeth with 2 cavities/tooth) were available with each treatment. The teeth were thermocycled (500 cycles at 5-50 degrees C) in synthetic saliva prior to artificial caries formation. After lesion formation, 5 longitudinal sections were taken from each specimen for polarized light evaluation. Mean surface lesion depths and wall lesion frequencies were determined. RESULTS: The Filtek Z250 group had significantly (P < 0.05, ANOVA, DMR) greater mean body of the lesion depths in coronal (205 microm) and root surfaces (221 microm) than either the Hytac (119 microm coronal and 161 microm root surfaces) or the Dyract AP (127 microm coronal and 149 microm root surfaces) groups. Likewise, wall lesion frequency was significantly higher (P < 0.05, ANOVA, DMR) for the Filtek Z250 group (41% coronal and 37% root surfaces) compared with either the Hytac (31% coronal and 25% root surfaces) or Dyract AP (26% coronal and 21% root surfaces) groups. No differences in outer body of the lesion depths or wall lesion frequencies were found between Hytac and Dyract AP for coronal and root surface restorations (P > 0.05, ANOVA, DMR).

Analysis of Variance↗
PubMed1999

Current research on the late Pliocene and Pleistocene deposits north of Homa Mountain, southwestern Kenya.

The late Pliocene and Pleistocene sediments of the Homa Peninsula in southwestern Kenya are richly fossiliferous, preserve Early Stone Age archaeological traces and provide one of the few paleoanthropological data sets for the region between the branches of the East African Rift Valley. This paper presents preliminary results of our ongoing investigation of late Pliocene and Pleistocene deposits at the localities of Rawi, Kanam East, Kanam Central and Kanjera. While fossils have been collected from the peninsula since 1911, little systematic effort has been made to place them into a broader litho-and chronostratigraphic framework. This project has conclusively demonstrated that fossils occur in good stratigraphic context at all of the study localities and that claims of sediment slumping (Boswell, 1935) have been greatly overstated (Behrensmeyer et al., 1995; Plummer & Potts, 1989). A provisional chronostratigraphic framework based on magneto- and biostratigraphy is presented here. We have revised the Plio-Pleistocene stratigraphy of the Rawi and Kanam gullies to include three formations: the Rawi, Abundu and Kasibos Formations. Based on magneto- and biostratigraphy, these formations are dated between approximately three and one m.y.a. (Gauss Chron-Jaramillo Subchron) (Cande & Kent, 1995). The Apoko Formation unconformably overlies the others and may be middle to late Pleistocene in age. All formations contain rich patches of fossils, and Acheulean artifacts have been surface collected from the Abundu and Kasibos Formations. Deposition of the fossil- and artefact-bearing sediments at Kanjera North began in the early Pleistocene and continued into the middle Pleistocene. Deposition at Kanjera South began over one million years earlier than previously thought, at approximately 2.2 m.y.a., and continued into the Olduvai Subchron (1.770-1.950 m.y.a.; Cande & Kent, 1995). Excavations have recovered Oldowan artefacts in association with well-preserved fossil fauna near the base of the sequence, the oldest archaeological traces yet known from southwestern Kenya.

Animals↗
PubMed1999

Research on late Pliocene Oldowan sites at Kanjera South, Kenya.

The late Pliocene is notable for the appearance of two new hominid genera as well as the first archaeological sites, generally attributed to the Oldowan Industrial Complex. However, the behavioral ecology of Oldowan hominids has been little explored, particularly at sites older than 2.0 Ma. Moreover, debates on Oldowan hominid foraging ecology and behavior have centered on data from only two regions, and often from single site levels. Here we describe the preliminary results of our investigation of Oldowan occurrences at Kanjera South. These occurrences preserve the oldest known traces of hominid activity in southwestern Kenya, and unlike most of the Oldowan sites in the 2.0-2.5 Ma time interval, artefacts are found in spatial association with a well-preserved fauna. In 1996 and 1997, this project initiated the first excavation program for Kanjera South. Magneto- and biostratigraphy indicate that deposition began approximately 2.2 Ma, substantially earlier than previously thought. At Excavation 1, artefacts were found in spatial association with a taxonomically diverse faunal assemblage in Beds KS-1 and KS-2. Excavation 2 yielded a partial hippopotamus axial skeleton with artefacts in KS-3. Cores from both sites were incidentally flaked and represent a Mode I lithic technology indistinguishable from the Oldowan. Approximately 15% of the artefacts were manufactured from non-local raw materials, indicating a flow of resources into the area. Stable isotopic analysis of KS-1 and KS-2 pedogenic carbonates suggests that the Excavation 1 assemblages formed in a relatively open (>75% C4 grass) habitat. The Excavation 1 and 2 faunas contain a high proportion of equids relative to Oldowan accumulations from Bed I Olduvai Gorge, Tanzania. Beds KS-1 and KS-2 thus preserve traces of Oldowan hominid activities in a more open setting than has been previously documented.

Animals↗
PubMed1998

Tracheobronchial mucoepidermoid carcinoma in childhood and adolescence: case report and review of the literature.

In children and adolescents, primary neoplasms of the tracheobronchial tree and lungs are rare, with most tumors involving the respiratory system being metastatic, small, blue cell tumors of childhood. Of the primary pulmonary neoplasms, most are malignant with mucoepidermoid carcinoma representing about 10% of these malignant tumors. We present an 8-year-old Hispanic male with hemoptysis and several episodes of pneumonia which initially was thought to be infectious upon biopsy during bronchoscopy, but proved to be mucoepidermoid carcinoma of the tracheobronchial tree by microscopic examination during an open lung biopsy. This rare tumor is more common in adults than in children, and infrequently presents with hemoptysis. Mucoepidermoid tumors of the tracheobronchial tree carry a more favorable prognosis in children than adults. In the adult population, the overall mortality is slightly less than 30%. In contrast, of the 31 reported cases of tracheobronchial mucoepidermoid carcinoma in pediatrics, all children are free of tumor involvement with a mean follow-up period of 5.8 years (range, 0.7-21 years). Based upon the available clinical outcome and survival data, it would appear that tracheobronchial mucoepidermoid carcinoma may be successfully managed by surgical intervention alone in children and adolescents.

Adolescent↗
PubMed1998

The changing pattern of substance abuse in urban adolescents.

OBJECTIVES: To determine the prevalence of specific drug use in adolescents attending an adolescent health clinic and to compare current rates with a similar previous study. DESIGN: Blinded and anonymous urine samples obtained from patients presenting for routine health care were tested for the presence of cannabinoids, phencyclidine (PCP), amphetamines, opiates, and cocaine. SETTING: Adolescent medicine outpatient clinic. PATIENTS: Patients were between 12 and 21 years of age. Specimens from 1313 patients in 1995 to 1996 and 1312 patients in 1989 to 1990 were tested. MAIN OUTCOME MEASURES: Current drug use rates were compared with a similar screening of patients conducted in 1989 to 1990. Comparisons between studies were made on the basis of specific drug, age, and sex. RESULTS: For the most recent patient group, 14% were positive for 1 or more drugs and 13% were positive for cannabinoids. Males were significantly more likely to test positive for drug use than females. The oldest adolescents were more likely to test positive for drug use than younger adolescents. Comparing the 2 study year cohorts, patients tested recently were significantly more likely to have urine tests positive for at least 1 drug and cannabinoids in particular and less likely to have urine tests positive for cocaine. CONCLUSIONS: There has been an increase in positive urine tests in patients seen in our ambulatory clinic, with a strong shift toward cannabinoids and a shift away from cocaine. Practitioners need to be aware that drug use patterns in adolescents can shift relatively abruptly and counseling should be targeted to current drug use patterns.

Adolescent↗
PubMed1998

Ibotenic acid lesions of the dorsal prefrontal cortex disrupt the expression of behavioral sensitization to cocaine.

The present study determined the effect of bilateral lesions of specific cortical or thalamic nuclei that provide excitatory amino acid afferents to the nucleus accumbens (i.e. the dorsal prefrontal cortex, ventral prefrontal cortex, amygdala, hippocampus and periventricular thalamus) on the expression of cocaine-induced behavioral sensitization. Lesions of these nuclei were made during a three-week withdrawal period following repeated daily injections of cocaine or saline. The results indicate that dorsal prefrontal cortex lesions block the expression of behavioral sensitization to cocaine, while ventral prefrontal cortex, fimbria fornix, amygdala and thalamic lesions have no effect. A subsequent microdialysis experiment was performed in order to evaluate the effect of dorsal prefrontal cortex lesions on glutamate transmission in the nucleus accumbens core of cocaine- and saline-pretreated rats. The systemic injection of cocaine produced a significant increase in extracellular glutamate in the nucleus accumbens core among animals with a sham surgery; this effect was blocked by a bilateral lesion of the dorsal prefrontal cortex. Taken together, these results indicate that the dorsal prefrontal cortex, which provides excitatory amino acid input selectively to the core region of the nucleus accumbens, enhances the expression of behavioral sensitization to cocaine by increasing glutamate transmission in this subnucleus.

Animals↗
PubMed1998

Increased drug use among old-for-grade and dropout urban adolescents.

INTRODUCTION: In tracking the epidemic of drug use in our communities, much emphasis has been placed on identifying predictive variables. In this study, we examine the relationship between drug use and school progress among a sample of inner-city adolescents. METHODS: A blinded, anonymous questionnaire covering a variety of health risk behaviors was administered to 1,720 adolescent patients who visited our outpatient clinic. Participants were classified as age-appropriate for last school grade completed, older than normal for grade, or as a dropout. A urine specimen was also collected in a blinded, anonymous fashion from each participant, and tested for five common substances of abuse. RESULTS: Nearly 12% of participants tested positive for drugs. Participants who were old for grade were over 40% more likely to be positive for drugs than grade-appropriate respondents, while school dropouts were more than twice as likely to test positive. CONCLUSIONS: These results demonstrate that being old-for-grade (OFG) and being a dropout in our population are markers for being at higher risk of substance abuse.

Achievement↗
PubMed1998

Assessment and management of three-and four-part proximal humeral fractures.

Three-and four-part comminuted fractures of the proximal humerus are difficult and technically demanding to treat. The various treatment methods reported in the literature are reviewed. It is recommended that three-part fractures be treated with open reduction and internal fixation. Four-part fractures in the younger, active patient also can be treated successfully with open reduction and internal fixation. However, in the elderly and in the patient with osteoporosis, a hemiarthroplasty is the treatment of choice. There is a need for universal agreement on a scoring system for measuring outcome in these fractures to allow a meaningful comparison between reported treatment methods.

Age Factors↗
PubMed1998

Isolation of Lautropia mirabilis from oral cavities of human immunodeficiency virus-infected children.

Lautropia mirabilis, a pleomorphic, motile, gram-negative coccus, has been isolated from the oral cavities of 32 of 60 (53.3%) children infected with human immunodeficiency virus (HIV) and 3 of 25 (12.0%) HIV-uninfected controls; the association of L. mirabilis isolation with HIV infection is significant (P < 0.001). All children in the study, both HIV-infected children and controls, were born to HIV-infected mothers. The presence of this bacterium was not associated with clinical disease in these children. The HIV-infected children with L. mirabilis did not differ from the HIV-infected children without L. mirabilis in immunological status, clinical status, or systemic medications. The role of HIV infection itself or concomitant factors in the establishment of L. mirabilis in the oral cavity remains to be elucidated.

Child↗