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Biomedical subjects

M Young

Publications and source records attributed to M Young.

At least 73 records · Page 4Linked to original sources
PubMed2000

Anaesthetic complications of acromegaly.

The anaesthetic risks of acromegaly include difficulties in airway management, hypertension, and cardiac, gastrointestinal and renal problems. To estimate the incidence of major complications in this rare group of patients, we reviewed 28 patients with acromegaly who had pituitary tumour excision over a 10-yr period. Each patient was matched for age, weight and sex to a non-acromegalic patient undergoing transsphenoidal pituitary surgery. Acromegalic patients received significantly more fentanyl and midazolam and less thiopental and succinylcholine than controls (all P < 0.05). Mean arterial pressure (baseline, minimal and maximal values) was higher in acromegalic patients than in controls. There was no difference between groups in the use of vasoactive drugs. PaO2, FIO2 and PaCO2 were similar in both groups. Arterial pH was significantly lower (P = 0.015), blood glucose was higher (P < 0.001) and fluid intake minus output was higher (P = 0.04) in acromegalic patients than in controls. Airway difficulty and tongue enlargement were encountered more often in acromegalic patients (P = 0.002 and P = 0.001, respectively). Our data confirm that in acromegalic patients: airway difficulties occurred more frequently; severe haemodynamic instability did not typically occur during surgery for acromegaly; pulmonary gas exchange was not altered during operation; glucose intolerance may be an intraoperative problem; and fluid regulation may be altered.

Acromegaly↗
PubMed2000

Effect of ceramide on intracellular glutathione determines apoptotic or necrotic cell death of JB6 tumor cells.

Selective induction of cell death is a means to remove unwanted cell populations from a tissue or organ. Understanding the signaling events responsible for mediating cell death by cytokines, such as tumor necrosis factor-alpha (TNFalpha) are key to the development of pharmacologic inducers of this response. Ceramide has been implicated as a secondary messenger for TNFalpha-induced cell death, but many of the intracellular effects of ceramide are not fully understood. Recent reports suggest that ceramide signaling may involve oxidative stress. To explore the relationship between TNF sensitivity and ceramide signaling, two genetic variants of mouse JB6 RT101 epidermal tumor cells, one resistant and one sensitive to TNFalpha-induced cytotoxicity, were treated with C2-ceramide. Treatment with 20 microM ceramide induced apoptosis and this was quickly followed by oncotic necrosis in the TNFalpha-sensitive JB6 (TNFs) cells. The same concentration of ceramide induced apoptosis, but not oncotic necrosis of the TNFalpha resistant JB6 (TNFr) cells. The basal level of glutathione was significantly higher in TNFr cells than in TNFs cells. Treatment with 20 microM ceramide decreased cellular glutathione in TNFs cells by 50%, in contrast to an insignificant decrease in the TNFr cells. A significant increase in reactive oxygen was noted in TNFs cells treated with 10 or 20 microM ceramide. Furthermore, pretreatment with the antioxidant N-acetylcysteine or with glutathione monoethylester delayed the onset of ceramide-induced oncotic necrosis, but did not inhibit apoptosis. Our results suggest that the severity of the decrease in glutathione appears to determine whether cells undergo just apoptosis or also oncotic necrosis. They also suggest that ceramide-induced oncotic necrosis is modulated by a decline in cellular glutathione and an elevation of reactive oxygen. These results suggest that a decrease in cellular redox potential determines susceptibility to ceramide-dependent killing pathways.

Acetylcysteine↗
PubMed2000

Effective treatment of a patient with a high-grade endometrial stromal sarcoma with an accelerated regimen of carboplatin and paclitaxel.

The rarity of endometrial stromal sarcoma (ESS) and its poor response to treatment provides fertile ground for investigational therapies. An accelerated regimen of carboplatin and paclitaxel is investigated. A patient with a recent history of treated tuberculosis of the lung represented with infertility and acute abdominal pain from suspected fibroids, and underwent a laparotomy with a diagnosis of a high-grade ESS. A novel therapeutic approach using a regimen of carboplatin and paclitaxel with the reinfusion of filgrastim-mobilized peripheral blood progenitor cells is described. A partial response was observed following six cycles of chemotherapy. Grade IV thrombocytopenia occurred after the last cycle, with recovery prior to pelvic radiotherapy. The patient remained well 1 year post-diagnosis. High-grade ESS is responsive to combination chemotherapy with paclitaxel and carboplatin, and requires further evaluation. The use of an accelerated regimen may also have contributed to the response and this question awaits randomized trials.

Adult↗
PubMed2000

Culturability of Mycobacterium tuberculosis cells isolated from murine macrophages: a bacterial growth factor promotes recovery.

Very little is known about the culturability and viability of mycobacteria following their phagocytosis by macrophages. We therefore studied populations of the avirulent 'Academia' strain of Mycobacterium tuberculosis isolated from murine peritoneal macrophage lysates several days post-infection in vivo. The resulting bacterial suspensions contained a range of morphological types including rods, ovoid forms and coccoid forms. Bacterial viability measured using the MPN method (dilution to extinction in liquid medium) was often much higher than that measured by CFU (plating on solid medium). Viability in the MPN assay was further enhanced when the Micrococcus luteus protein, Rpf, was incorporated into the liquid culture medium at picomolar concentrations. Rpf is an example of a family of autocrine growth factors found throughout the high G+C cohort of Gram-positive bacteria including M. tuberculosis. M. tuberculosis cells obtained from macrophages had altered surface properties, as compared with bacteria grown in vitro. This was indicated by loss of the ability to adsorb bacteriophage DS6A, a reduced tendency to form clumps, acquisition of ethidium bromide stainability following heat treatment, and loss of Rpf-mediated resuscitation following freezing and thawing. These results indicate that a proportion of 'unculturable' M. tuberculosis cells obtained from macrophages is either injured or dormant and that these cells may be recovered or resuscitated using Rpf in liquid medium.

Animals↗
PubMed2000

A review of a major driver rehabilitation centre: a ten-year client profile.

Driver Rehabilitation Services at Bloorview MacMillan Centre in Toronto provide important assessment and rehabilitation services for persons with various physical, neurological, and medical disabilities. Each year, the programme sees approximately 700 to 800 clients. Since 1985, the earliest year for which records are currently available, the program has seen approximately 7300 clients. The client information filing system consists predominantly of paper reports filed alphabetically by hand. A comprehensive computer database program was implemented in 1996 to organize and analyze client-driver records more efficiently. A systematic random sample consisting of 364 records (5% of the total population) was examined to describe the characteristics of the population within five major study categories: demographics, administration, medical information, visual and perceptual abilities and driving record.

Adolescent↗
PubMed2000

Domestic violence and childhood sexual abuse in HIV-infected women and women at risk for HIV.

OBJECTIVES: The purpose of this study was to determine the prevalence and effect of domestic violence and childhood sexual abuse in women with HIV or at risk for HIV infection. METHODS: Participants with HIV or at risk for HIV infection enrolled in the Women's Interagency HIV Study. Childhood sexual abuse; all physical, sexual, and coercive violence by a partner; HIV serostatus; demographic data; and substance use and sexual habits were assessed. RESULTS: The lifetime prevalence of domestic violence was 66% and 67%, respectively, in 1288 women with HIV and 357 uninfected women. One quarter of the women reported recent abuse, and 31% of the HIV-seropositive women and 27% of the HIV-seronegative women reported childhood sexual abuse. Childhood sexual abuse was strongly associated with a lifetime history of domestic violence and high-risk behaviors, including using drugs, having more than 10 male sexual partners and having male partners at risk for HIV infection, and exchanging sex for drugs, money, or shelter. CONCLUSIONS: Our data support the hypothesis of a continuum of risk, with early childhood abuse leading to later domestic violence, which may increase the risk of behaviors leading to HIV infection.

Adolescent↗
PubMed2000

Sexual satisfaction among married women age 50 and older.

Correlates of sexual satisfaction were identified in a sample of older married women. A 70-item questionnaire was mailed to an age-stratified sample of 5,000 married persons, including 1,000 married women over the age of 50. Usable questionnaires were received from 148 participants (14.8% return rate). Hierarchical multiple regression analysis, using sexual satisfaction as the dependent variable, yielded five predictor variables that accounted for a significant portion of the variation in sexual satisfaction (Cumulative R2 = .73). These results serve as a reminder that sexual interactions cannot be compartmentalized but must be considered within the context of the overall marriage relationship. Given the low return rate, interpretations should be limited until replication with an adequate sample has been completed.

Adult↗
PubMed2000

Butanol tolerance of Clostridium beijerinckii NCIMB 8052 associated with down-regulation of gldA by antisense RNA.

Strain BR54 of Clostridium beijerinckii was derived from the wild type strain, NCIMB 8052, by mutagenesis with Tn1545 and selection for butanol tolerance. It harbours a single copy of Tn 1545 in a 435 bp intergenic region separating two convergently transcribed genes, accC and gldA. The former encodes biotin carboxylase (E.C.6.3.4.14), a subunit of acetyl-CoA carboxylase and the latter encodes glycerol dehydrogenase (E.C.1.1.1.6). Since Tn1545 generates outwardly directed transcripts from its right end, we considered the possibility that the transposon inserted in strain BR54 might affect the expression of the adjacent gldA gene. RT-PCR experiments revealed that the mutant, but not the wild type, contains antisense RNA corresponding to the gldA gene. Correlated with this, the level of glycerol dehydrogenase activity in the mutant was only 25% of that in the wild type when bacteria were grown with either glucose or glycerol as the fermentable substrate. We conclude that transcripts emerging from the right end of the conjugative transposon, Tn1545, can reduce the expression of the adjacent gldA gene by the generation of antisense RNA and that this is associated with a butanol-tolerant phenotype.

ATP-Binding Cassette Transporters↗
PubMed2000

A new insertion sequence, ISCb1, from Clostridium beijernickii NCIMB 8052.

The NCIMB 8052 strain of Clostridium beijerinckii contains nine copies of a novel insertion sequence, ISCb1, belonging to the IS4 family. The 1764 bp element has 18 bp inverted repeats at its extremities, and generates 11 bp target repeats upon insertion. It contains a 1365 bp ORF whose predicted product (455 amino acids) resembles bacterial transposases. The highly conserved DD(35)E motif is present, as are signatures characteristic of the N3 and C1 domains of bacterial transposases. Codon usage of the ORF is somewhat different from that of other C. beijerinckii genes, suggesting that ISCb1 may have been acquired from another organism by horizontal gene transfer in the evolutionary past. One ISCb1 copy lies close to the site of insertion of Tn 1545 in a mutant strain, C10, which shows a reduced tendency to degenerate (i.e. loss of the potential to form solvents) compared with the wild type. In the C10 strain, the characteristic pattern of DNA fragments detected by an IS-specific probe was altered, but this was due to the Tn1545 insertion itself, rather than an ISCb1-mediated genome re-arrangement. There is currently no evidence that the element is involved in strain degeneration, since 12 independently isolated spontaneous mutants that had lost the ability to form solvents had the same ISCb1 profile as that of the wild type strain. The element is apparently restricted to a series of closely related solvent-forming clostridia.

Amino Acid Sequence↗
PubMed2000

Insomnia and the eye of the beholder: are there clinical markers of objective sleep disturbances among adults with and without insomnia complaints?

Previous findings suggest that some who report insomnia sleep well, whereas some noncomplaining individuals sleep rather poorly. This study was conducted to determine if mood, anxiety, and sleep-related beliefs might relate to perceived sleep disturbance. Thirty-two women and 32 men (aged 40-79 years) with primary insomnia and an aged-matched sample of 61 normal sleepers (31 women, 30 men) completed 6 nocturnal sleep recordings, as well as the Beck Depression Inventory (BDI), the Trait portion of the State-Trait Anxiety Inventory (STAI-2), and the Dysfunctional Beliefs and Attitudes About Sleep Questionnaire. Sleep and interview data were used to subdivide the majority of the sample (n = 108) into objective normal sleepers and subjective insomnia sufferers who seemingly slept well and subjective normal sleepers and objective insomnia sufferers who slept poorly. The 2 subjective subgroups showed the most marked differences on most of the psychometric measures. The findings suggest that the psychological factors scrutinized in this study may mediate sleep satisfaction and/or predict objective sleep difficulties.

Adult↗
PubMed2000

Caring for patients with coloanal reservoirs for rectal cancer.

Advances in surgical techniques enable select patients with rectal cancer to have sphincter-saving procedures that restore the continuity of the GI tract, eliminating the need for a permanent colostomy. One of the preferred surgical options is the construction of a coloanal reservoir or colonic J-pouch. This procedure is usually performed in two stages (two surgeries) and involves creating a temporary ileostomy. Patients undergoing treatment for rectal cancer frequently require adjunctive therapy for the disease before and after surgery. They require extensive education and support during the course of treatment and through rehabilitation.

Humans↗
PubMed1999

A phase II trial of 200% ProMACE-CytaBOM in patients with previously untreated aggressive lymphomas: analysis of response, toxicity, and dose intensity.

We showed in a phase I trial that the maximum tolerated dose of the ProMACE-CytaBOM regimen in patients with aggressive lymphoma was 200% (Gordon et al, J Clin Oncol 14:1275, 1996). Based on these observations, we initiated a phase II trial designed to determine response, toxicity, and dose intensity using this regimen. We analyzed 74 patients with advanced-stage (III or IV) or bulky stage II aggressive lymphoma. The overall complete response rate was 69% (72% in evaluable patients). With a median follow-up of 4.5 years, the median survival has not yet been reached. The 4-year survival rate is 73% (95% confidence interval [CI] 62, 83%) and no difference was observed among International Prognostic Index (IPI) groups. The 4-year disease-free survival was 71% (95% CI 58, 84%) with no statistical difference between patients with IPI 0 to 1 versus 2 to 4. The toxicity was acceptable, though the grade 4 hematologic toxicity rate for this regimen was 100%. Grade 4 nonhematologic toxicity was 36%. Three cases of either myelodysplastic syndrome or acute leukemia occurred at 7 months, 3.4 years, and 4.2 years after registration. Cytogenic analysis was available in two cases, showing inv(16) without French American British classification (FAB) M4 EO histology in one patient and a 5q-syndrome in the other. These data suggest that 200% ProMACE-CytaBOM with either granulocyte-macrophage colony-stimulating factor (GM-CSF) or G-CSF results in a high complete remission rate and a disease-free survival comparable to any prior risk-based analysis in aggressive lymphoma. Before using this regimen in general practice, phase III clinical trials should be conducted.

Adult↗
PubMed1999

HIV-1 RNA in plasma and genital tract secretions in women infected with HIV-1.

To assess antiretroviral therapy, all compartments, including the genital tract, need to be evaluated. HIV-1 RNA was quantified in whole cervicovaginal lavage fluid (CVL) and plasma of 56 women and in the cellular and supernatant fractions of 27 of these women. Overall, we detected HIV-1 RNA in 59% of whole CVL samples and in 61% and 44% of cellular and supernatant fractions of the subset of women, respectively. Detectability of HIV-1 RNA in CVL increased with increasing level of plasma RNA in both unfractionated and cell-associated CVL components (p = .0004 and .002, respectively), but not in the cell-free fraction (p = .29). Mean HIV-1 RNA levels in CVL increased with decreasing CD4 counts (p = .002,) and with increasing plasma HIV-1 RNA (p < .001). Adjusted odds ratios (OR) for detectable CVL RNA were highest for women with CD4 counts <200 cells/mm3 (OR, 10.1; 95% confidence interval [CI]: 1.6-82.7; p = .02) and >50,000 copies/ml of plasma RNA (OR, 25.2; 95% CI, 3.2-554; p = .01). Treatment did not seem to affect RNA detection in CVL after adjusting for plasma RNA and CD4. In conclusion, we found that detectability and level of CVL RNA were closely associated with the cellular fraction of genital secretions in women and strongly correlated with the level of plasma RNA and CD4. Genital tract secretions may need to be tested in the assessment of treatment efficacy and this can easily be accomplished with this rapid and easy procedure using whole CVL.

CD4 Lymphocyte Count↗
PubMed1999

Sexual, contraceptive, and drug use behaviors of women with HIV and those at high risk for infection: results from the Women's Interagency HIV Study.

OBJECTIVE: To document the sexual and contraceptive practices of women with HIV infection or who are at risk for infection. DESIGN: Data on the baseline behaviors of 561 HIV-negative and 2040 HIV-positive women were collected as part of the Women's Interagency HIV Study (WIHS). WIHS is a multisite, longitudinal study following the natural history of HIV infection among women in the United States. METHODS: Each participant contributed an interviewer administered, self-report interview including questions on sexual and contraceptive behavior. RESULTS: Women with HIV were less likely to report heterosexual activity in the previous 6 months (65% HIV-positive, 76% HIV-negative). Among sexually active women, there were no differences in the proportion of those reporting vaginal (97% HIV-positive, 98% HIV-negative) or anal sex (12% HIV-positive, 10% HIV-negative), although women with HIV were less likely to report cunnilingus (41% HIV-positive, 70% HIV-negative) and fellatio (48% HIV-positive, 57% HIV-negative). Of women with HIV, 63% always used condoms during vaginal sex (versus 28% HIV-negative), with lower rates reported during other sexual activities. Crack, cocaine, or injecting drug use, reported by 27% of HIV-positive and 35% of HIV-negative women, was associated with inconsistent condom use, independent of serostatus. HIV-positive women who reported using condoms and another contraception method were less consistent condom users (57% consistent versus 67%). CONCLUSIONS: The prevalence of sexual risk behavior in this sample suggests that, although women with HIV exhibit lower levels of sexual risk behavior than uninfected women, many have not been successfully reached with regard to implementing safer behaviors. These findings have implications for more widespread and effective behavioral intervention efforts.

Adolescent↗
PubMed1999

Cervicovaginal human papillomavirus infection in human immunodeficiency virus-1 (HIV)-positive and high-risk HIV-negative women.

BACKGROUND: Human papillomavirus (HPV) infection is associated with precancerous cervical squamous intraepithelial lesions commonly seen among women infected with human immunodeficiency virus-1 (HIV). We characterized HPV infection in a large cohort of HIV-positive and HIV-negative women participating in the Women's Interagency HIV Study to determine the prevalence of and risk factors for cervicovaginal HPV infection in HIV-positive women. METHODS: HIV-positive (n = 1778) and HIV-negative (n = 500) women were tested at enrollment for the presence of HPV DNA in a cervicovaginal lavage specimen. Blood samples were tested for HIV antibody status, level of CD4-positive T cells, and HIV RNA load (copies/mL). An interview detailing risk factors was conducted. Univariate and multivariate analyses were performed. RESULTS: Compared with HIV-negative women, HIV-positive women with a CD4+ cell count of less than 200/mm3 were at the highest risk of HPV infection, regardless of HIV RNA load (odds ratio [OR] = 10.13; 95% confidence interval [CI] = 7.32-14.04), followed by women with a CD4+ count greater than 200/mm3 and an HIV RNA load greater than 20,000 copies/mL (OR = 5.78; 95% CI = 4.17-8.08) and women with a CD4+ count greater than 200/mm3 and an HIV RNA load less than 20,000 copies/mL (OR = 3.12; 95% CI = 2.36-4.12), after adjustment for other factors. Other risk factors among HIV-positive women included racial/ethnic background (African-American versus Caucasian, OR = 1.64; 95% CI = 1.19-2.28), current smoking (yes versus no; OR = 1.55; 95% CI = 1.20-1.99), and younger age (age < 30 years versus > or = 40 years; OR = 1.75; 95% CI = 1.23-2.49). CONCLUSIONS: Although the strongest risk factors of HPV infection among HIV-positive women were indicators of more advanced HIV-related disease, other factors commonly found in studies of HIV-negative women, including racial/ethnic background, current smoking, and age, were important in HIV-positive women as well.

AIDS-Related Opportunistic Infections↗