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Biomedical subjects

D Ross

Publications and source records attributed to D Ross.

At least 91 records · Page 5Linked to original sources
PubMed1999

Lateralizing value of interictal spikes on overnight sleep-EEG studies in temporal lobe epilepsy.

PURPOSE: To determine the lateralizing value of interictal epileptiform discharges (IEDs) recorded during overnight sleep-EEG studies in temporal lobe epilepsy. Because IEDs are more prevalent in non-rapid eye movement (NREM) sleep than in wakefulness, overnight sleep-EEG recordings may contribute additional lateralizing information to the epilepsy surgery evaluation beyond daytime EEGs. METHODS: Twenty-four subjects with medically refractory temporal lobe epilepsy underwent continuous overnight sleep-EEG recordings. Subjects were seizure free > or =24 h before study and receiving stable doses of medication. The IED foci recorded on overnight studies were compared with daytime EEGs, interictal samples, and ictal recordings during long-term monitoring, brain magnetic resonance images (MRIs), and surgical outcome. RESULTS: (a) In all 24 subjects, including 13 without IEDs on daytime EEGs, temporal IEDs were present during NREM sleep and were exclusively or predominantly (>95%) unilateral in 15 and bitemporal in nine. (b) Unilateral NREM IEDs were concordant with surface or depth ictal-onset regions in 14 subjects, even if MRIs were normal (three subjects) or surface ictal-onset regions were bilateral (five subjects). Eleven of 12 subjects with unilateral concordant NREM IEDs who have undergone surgery are seizure free. (c) Bitemporal IEDs were associated with postoperative seizures in all subjects with normal MRIs or widespread MRI abnormalities. However, all subjects with bitemporal IEDs and MRI hippocampal abnormalities concordant with ictal-onset regions had good to excellent surgical outcomes. CONCLUSIONS: When combined with other investigations, IEDs recorded on overnight studies add prognostic data to the epilepsy surgery evaluation not provided by daytime EEGs.

Adult↗
PubMed1999

Patient acceptability of and tolerance to a placebo intravaginal ring in hysterectomized women: a pilot study.

OBJECTIVE: To assess the tolerance to and patient acceptability of a placebo intravaginal ring in hysterectomized, postmenopausal women over a 28-day period. DESIGN: Open, single-center. SETTING: University hospital specialist menopause clinic. PARTICIPANTS: A total of 24 healthy postmenopausal women attending menopause clinics at King's College Hospital and the Amarant Centre, London. MAIN OUTCOME MEASURES: Discomfort, ring expulsions, bowel, urinary and sexual difficulties associated with the ring and women's overall views on this method. RESULTS: The major problems with use of the intravaginal ring were patient discomfort, involuntary ring expulsion and sexual partner discomfort. These were experienced by 13, 11 and seven women and their partners, respectively, and resulted in premature discontinuation by three women who suffered discomfort and two women who experienced recurrent involuntary ring expulsion. CONCLUSIONS: Two-thirds of the patients found the intravaginal ring acceptable, one-third did not.

Administration, Intravaginal↗
PubMed1999

Lower extremity compartment syndrome. When to suspect acute or chronic pressure buildup.

Acute compartment syndrome is a surgical emergency. A high index of suspicion is needed in cases of severe contusion, especially if patient complaints seem to outweigh physical findings. Acute surgical fasciotomy is an effective treatment and should be carried out expeditiously if compartment pressures are elevated over 70 mm Hg in order to avoid complications such as chronic disability due to contractures or rhabdomyolysis with acute renal failure. Chronic exertional compartment syndrome most often occurs in the anterior or the lateral compartment. Patients have only exercise-related symptoms and recover quickly after resting from the inciting activity. Diagnosis is difficult, but the anterior compartment pressure may be checked fairly readily with a handheld pressure catheter. Deep posterior compartment problems are harder to check because of the difficulty in reaching this area. Thallium stress testing appears promising for diagnosing both anterior and posterior problems and may augment, or even replace, the catheter measurement in the deep posterior and perhaps even the anterior compartment. Thallium stress testing is noninvasive and may be a more physiologic measurement. Fasciotomy may be indicated if conservative treatment lacks efficacy. For unknown reasons, the deep posterior compartment does not respond as quickly, or as well, to fasciotomy as the anterior compartment.

Acute Disease↗
PubMed1999

Large ovarian cellular fibroma during pregnancy mimicking a lipid cell tumor.

Lipid cell tumors are extremely rare tumors of the ovary which are usually malignant when larger than eight centimeters. Fibromas, on the other hand, are the most common type of benign ovarian solid tumors. Neither one of these tumors are known to be accelerated by the pregnant state. We report a case of a healthy 15-year-old female who was found to have an ovarian mass during pregnancy. This fibroma weighed more than 3,800 grams and mimicked a lipid cell tumor. Cesarean section and unilateral oophorectomy resulted in a good outcome for both mother and child.

Adenocarcinoma↗
PubMed1998

Recruitment of non-patient volunteers with schizophrenia spectrum personality symptoms.

Authors aimed to evaluate the yield and effectiveness of recruiting community schizophrenia spectrum personality (SSP) subjects via targeted newspaper advertisements listing SSP traits. Eight newspaper advertisements listing SSP traits were placed in regional newspapers over a 3-year period. Respondents (n = 209) were screened thoroughly via telephone, and eligible subjects were invited for face-to-face clinical interviews. One hundred and one subjects (48% of the respondents) were screened out over the phone and another 30% were no-shows or refused. Of the 46 subjects who were interviewed, a majority (24 subjects; 52%) met this study's criteria for SSP. These subjects experienced significant psychotic-like symptoms, as ascertained by a self-rating scale, and showed a downward drift in their socio-economic status. One can successfully recruit SSP subjects, with high yield, using targeted telephone advertisements combined with thorough telephone screening.

Adult↗
PubMed1998

Indolequinone antitumor agents: correlation between quinone structure, rate of metabolism by recombinant human NAD(P)H:quinone oxidoreductase, and in vitro cytotoxicity.

A series of indolequinones bearing various functional groups has been synthesized, and the effects of substituents on the metabolism of the quinones by recombinant human NAD(P)H:quinone oxidoreductase (NQO1) were studied. Thus 5-methoxyindolequinones were prepared by the Nenitzescu reaction, followed by functional group interconversions. The methoxy group was subsequently displaced by amine nucleophiles to give a series of amine-substituted quinones. Metabolism of the quinones by NQO1 revealed that, in general, compounds with electron-withdrawing groups at the indole 3-position were among the best substrates, whereas those with amine groups at the 5-position were poor substrates. Compounds with a leaving group at the 3-indolyl methyl position generally inactivated the enzyme. The toxicity toward non-small-cell lung cancer cells with either high NQO1 activity (H460) or no detectable activity (H596) was also studied in representative quinones. Compounds which were good substrates for NQO1 showed the highest selectivity between the two cell lines.

Antineoplastic Agents↗
PubMed1998

Outcome after treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma.

BACKGROUND: Treatment of differentiated thyroid cancer has been studied for many years, but the benefits of extensive initial thyroid surgery and the addition of radioiodine therapy or external radiation therapy remain controversial. OBJECTIVE: To determine the relations among extent of surgery, radioiodine therapy, and external radiation therapy in the treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma. DESIGN: Analysis of data from a multicenter study. SETTING: 14 institutions in the United States and Canada participating in the National Thyroid Cancer Treatment Cooperative Study Registry. PATIENT: 385 patients with high-risk thyroid cancer (303 with papillary carcinoma and 82 with follicular carcinoma). MEASUREMENTS: Death, disease progression, and disease-free survival. RESULTS: Total or near-total thyroidectomy was done in 85.3% of patients with papillary carcinoma and 71.3% of patients with follicular cancer. Overall surgical complication rate was 14.3%. Total or near-total thyroidectomy improved overall survival (risk ratio [RR], 0.37 [95% CI, 0.18 to 0.75]) but not cancer-specific mortality, progression, or disease-free survival in patients with papillary cancer. No effect of extent of surgery was seen in patients with follicular thyroid cancer. Postoperative iodine-131 was given to 85.4% of patients with papillary cancer and 79.3% of patients with follicular cancer. In patients with papillary cancer, radioiodine therapy was associated with improvement in cancer-specific mortality (RR, 0.30 [CI, 0.09 to 0.93 by multivariate analysis only]) and progression (RR, 0.30 [CI, 0.13 to 0.72]). When tall-cell variants were excluded, the effect on outcome was not significant. After radioiodine therapy, patients with follicular thyroid cancer had improvement in overall mortality (RR, 0.17 [CI, 0.06 to 0.47]), cancer-specific mortality (RR, 0.12 [CI, 0.04 to 0.42]), progression (RR, 0.21 [CI, 0.08 to 0.56]), and disease-free survival (RR, 0.29 [CI, 0.08 to 1.01]). External radiation therapy to the neck was given to 18.5% of patients and was not associated with improved survival, lack of progression, or disease-free survival. CONCLUSIONS: This study supports improvement in overall and cancer-specific mortality among patients with papillary and follicular thyroid cancer after postoperative iodine-131 therapy. Radioiodine therapy was also associated with improvement in progression in patients with papillary cancer and improvement in progression and disease-free survival in patients with follicular carcinoma.

Adenocarcinoma, Follicular↗
PubMed1998

GAC1, a new member of the leucine-rich repeat superfamily on chromosome band 1q32.1, is amplified and overexpressed in malignant gliomas.

We have used two-dimensional electrophoresis of enzyme-digested genomic DNA to identify a novel gene GAC1, which maps at 1q32.1 and which is overexpressed in malignant gliomas in which it is amplified. GAC1 encodes a protein which belongs to the leucine-rich repeat superfamily. Amplification and overexpression of GAC1 was demonstrated in two of eight tumors where amplifications were previously evidenced by comparative genomic hybridization (one glioblastoma multiforme and one anaplastic astrocytoma), and in one of eight unselected glioblastomas multiforme. GAC1 exhibits sequence homology with other proteins which function as cell-adhesion molecules or as signal transduction receptor and is a likely candidate for the target gene in the 1q32.1 amplicon in malignant gliomas.

Amino Acid Sequence↗
PubMed1998

Oxidation of 1,3-butadiene to (R)- and (S)-butadiene monoxide by purified recombinant cytochrome P450 2E1 from rabbit, rat and human.

1,3-Butadiene (BD) is a gas used widely in the rubber and plastics industry as an intermediate in production processes and has been detected in automobile exhaust and cigarette smoke. BD requires metabolic activation to exert toxicity and has been shown to be carcinogenic in rodents. IARC has classified BD as a group 2A (probably carcinogenic to humans) carcinogen. The initial oxidation of BD to butadiene monoxide (BMO) occurs primarily via cytochrome P450 2E1 and two stereoisomers of BMO (R and S) can be formed. (R) and (S)-BMO are metabolized differently and demonstrate markedly different toxicities in isolated rat hepatocytes. This work examined the generation of (R) and (S)-BMO from BD by cytochrome P450 2E1 from rabbit, rat and human. BMO level was measured by GC-MS analysis and enantiomeric composition was determined by GC-FID. The greatest rate of formation of BMO from BD was obtained with rabbit cytochrome P4502E1 followed by human and then by rat. Enantiomeric distribution of R and S-BMO produced by the three species demonstrated no significant differences.

Animals↗
PubMed1998

Indolequinone antitumor agents: relationship between quinone structure and rate of metabolism by recombinant human NQO1.

A series of indolequinones bearing various functional groups has been synthesized, and the effects of substituents on the metabolism of the quinones by recombinant human NAD(P)H:quinone oxidoreductase (NQO1), and on the toxicity toward nonsmall cell lung cancer cells with either high NQO1 activity (H460) or with no detectable activity (H596) were studied.

Antineoplastic Agents↗
PubMed1998

Serologic association of human herpesvirus eight with posttransplant Kaposi's sarcoma in Saudi Arabia.

BACKGROUND: This study investigates the association between human herpesvirus eight (HHV8) and Kaposi's sarcoma (KS), the most common cancer occurring in renal transplant recipients in Saudi Arabia. METHODS: A cross-sectional study of seroreactivity to HHV8 antigens in posttransplant KS patients from a tertiary care hospital in Riyadh, Saudi Arabia, and in control subjects without KS was conducted. Seroreactivity rates were determined using immunoblotting assays to detect antibodies to two lytic cycle HHV8 antigens: p40, an antigen found in infected cells, and sVCA, an HHV8-encoded small viral capsid antigen expressed in Escherichia coli. RESULTS: Antibodies to HHV8 p40 and sVCA were present in a significantly higher proportion of renal transplant patients with KS (13 of 14 patients) compared to renal transplant patients without KS (5 of 18; P<0.001) and compared to other control individuals (6 of 44; P<0.001). HHV8 seroreactivity was more common among patients with renal failure (28%) than among other control groups (7%). CONCLUSIONS: The serologic results provide evidence of a strong association between HHV8 and posttransplant KS in Saudi Arabia.

Antibodies, Viral↗
PubMed1998

Stereochemical aspects of the conjugation of epoxide metabolites of butadiene with glutathione in rat liver cytosol and freshly isolated rat hepatocytes.

1,3-Butadiene (BD), a gas used widely in production and synthesis of rubber, plastics, and resins, is metabolized to three different epoxide metabolites: butadiene monoxide (BMO), butadiene bisoxide (BBO) and epoxybutanediol (ED). We have examined the role of stereochemistry in the chemical and enzyme-mediated conjugation of R- and S-BMO; RR-, SS-, and meso-BBO; and SR-, RS-, RR-, and SS-ED with glutathione (GSH) using liver cytosol and freshly isolated hepatocytes from male Sprague-Dawley rats. Chemical and enzyme-mediated reactivity of BD-epoxides (5 mM) with GSH (0.1 mM) was assessed by measuring remaining GSH in solution using dithiobisnitrobenzoic acid (DTNB). Chemical reactivity of BD epoxides with GSH was modest while addition of cytosol resulted in increased removal of GSH following exposure to each BD-epoxide. BBO stereoisomers resulted in the greatest cytosol-mediated removal of GSH (40-70%). BMO enantiomers removed 40-60% and ED stereoisomers removed 10-35% of GSH. Cytosol-mediated reactions with GSH were predictive of results observed in isolated hepatocytes where stereoselective depletion of GSH was observed following treatment with each class of epoxide metabolites. R-BMO depleted cellular GSH more rapidly and to a greater extent than S-BMO, SS- and meso-BBO were more potent than RR-BBO and SS- and SR-ED were more potent than RS- and RR-ED. These data demonstrate that enzyme-mediated reactions represent the primary mechanism of conjugation of BD-epoxides with GSH and that these reactions display marked stereoselectivity.

Animals↗
PubMed1998

Treatment of malnutrition with 1.1% amino acid peritoneal dialysis solution: results of a multicenter outpatient study.

A peritoneal dialysis (PD) solution containing 1.1% amino acids as the osmotic agent was evaluated in a 3-month randomized, prospective, open-label study in malnourished PD patients. Patients in the treatment group (DAA) received one or two exchanges daily with the amino acid solution, depending on tolerance, in place of glucose solutions. Controls (DD) received their usual therapy with glucose dialysate. Fifty-four DAA and 51 DD patients completed the study. In DAA, but not in DD patients, there was a significant increase at month 3 in serum insulin-like growth factor-1 (IGF-1) levels and significant decreases in serum potassium (all 3 months) and inorganic phosphorus levels (months 1 and 3), indicating a general anabolic response. Prealbumin and transferrin levels were significantly increased in DAA but not in DD patients at month 1, but the groups did not differ at months 2 and 3. In patients with baseline albumin levels less than 3.5 g/dL (bromcresol green [BCG] method), DAA patients showed increases in albumin, transferrin (months 1 and 2), and prealbumin levels (all 3 months) relative to baseline values, whereas these serum protein levels were unchanged in DD patients, although the changes from baseline did not differ between groups. In this subgroup, midarm muscle circumference (MAMC) did not change in DD or DAA patients. In patients with baseline albumin levels of 3.5 g/dL or greater, DD patients had decreases in albumin and total protein levels at all 3 months and in prealbumin levels at months 1 and 2, relative to baseline. In DAA patients, there were fewer changes in serum proteins. MAMC increased significantly from baseline in DAA but not in DD patients, although changes from baseline did not differ between DAA and DD groups. DAA patients showed no changes in peritoneal membrane transport characteristics. The results indicate that treatment with one or two exchanges daily of this amino acid-based PD solution is safe and provides nutritional benefit for malnourished PD patients.

Amino Acids↗
PubMed1998

An approach to setting priorities in health planning.

This paper describes work undertaken in Pakistan within a project to strengthen the health planning system, aimed at improving the capacity of the planning cells to identify priorities and develop broad strategic guidelines. The work starts from the premise that identification of priorities requires two stages. In the first stage, problems must be structured and defined in a way that is accepted by all major stakeholders in the planning process. In the second stage, a transparent process of decision making must exist which will provide the means for the planning group to establish priorities and time-scales. The tools chosen in this instance were selected in relation to the characteristics of the local environment, and the paper describes these.

Decision Making, Organizational↗