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Biomedical subjects

A B Williams

Publications and source records attributed to A B Williams.

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

Prospective assessment of accuracy of endoanal MR imaging and endosonography in patients with fecal incontinence.

OBJECTIVE: Endoanal MR imaging was prospectively compared with anal endosonography to determine any superiority in the characterization of sphincter morphology in fecal incontinence. SUBJECTS AND METHODS: Fifty-two consecutive patients with fecal incontinence were examined with anal endosonography and endoanal MR imaging after a detailed bowel history, clinical examination, and complete anorectal physiologic testing. External and internal anal sphincter integrity was noted on both endosonograms and MR images by two radiologists in consensus, who read individual scans in a random order to avoid recall bias. Imaging findings were subsequently compared, and arbitration of any disagreement between endosonography and MR imaging was made in consensus by a surgeon and a gastroenterologist who also had access to the patient's history, clinical examination, and anorectal physiologic testing results. RESULTS: Complete agreement was found between anal endosonographic and MR imaging interpretations in 32 patients (62%): 10 with combined external and internal sphincter injuries, two with isolated internal sphincter injury, and 20 with intact sphincters. Of 20 patients in whom results of the scans were disparate, incorrect interpretation was found on endosonography in six patients, on MR imaging in 15. Overall, one error relating to the internal sphincter was made on endosonography versus 12 on MR imaging (p = 0.002), and five errors relating to the external sphincter were made on endosonography versus six on MR imaging (p = 1.0). CONCLUSION: This study suggests that endoanal sonography and endoanal MR imaging are equivalent in diagnosing external anal sphincter injury, but MR imaging is inferior in diagnosing internal anal sphincter injury.

Adolescent↗
PubMed1999

Sepsis stimulates release of myofilaments in skeletal muscle by a calcium-dependent mechanism.

Sepsis is associated with a pronounced catabolic response in skeletal muscle, mainly reflecting degradation of the myofibrillar proteins actin and myosin. Recent studies suggest that sepsis-induced muscle proteolysis may reflect ubiquitin-proteasome-dependent protein breakdown. An apparently conflicting observation is that the ubiquitin-proteasome pathway does not degrade intact myofibrils. Thus, it is possible that actin and myosin need to be released from the myofibrils before they can be ubiquitinated and degraded by the proteasome. We tested the hypothesis that sepsis results in disruption of Z-bands, increased expression of calpains, and calcium-dependent release of myofilaments in skeletal muscle. Sepsis induced in rats by cecal ligation and puncture resulted in increased gene expression of micro-calpain, m-calpain, and p94 and in Z-band disintegration in the extensor digitorum longus muscle. The release of myofilaments from myofibrillar proteins was increased in septic muscle. This response to sepsis was blocked by treating the rats with dantrolene, a substance that inhibits the release of calcium from intracellular stores to the cytoplasm. The present results provide evidence that sepsis is associated with Z-band disintegration and a calcium-dependent release of myofilaments in skeletal muscle. Release of myofilaments may be an initial and perhaps rate-limiting component of sepsis-induced muscle breakdown.

Actin Cytoskeleton↗
PubMed1999

Sepsis is associated with increased ubiquitinconjugating enzyme E214k mRNA in skeletal muscle.

Previous studies provided evidence that sepsis is associated with increased ubiquitin-proteasome-dependent protein breakdown in skeletal muscle. The 14-kDa ubiquitin-conjugating enzyme (E214k) has been proposed to be a key regulator of the ubiquitin proteolytic pathway. We tested the hypothesis that E214k message and protein levels are increased in skeletal muscle during sepsis. Sepsis was induced in rats by cecal ligation and puncture (CLP). Control rats were sham operated. E214k mRNA and protein levels were quantitated after Northern and Western blot analysis, respectively, 16 h after CLP or sham operation. Sepsis resulted in a 70% increase in the 1. 2-kb E214k transcript in the fast-twitch extensor digitorum longus muscle, whereas no changes were seen in the slow-twitch soleus muscle. E214k protein levels were not influenced by sepsis in any of the muscles studied. Although the changes in the expression of the E214k 1.2-kb transcript paralleled the differential effect of sepsis on protein breakdown in fast- and slow-twitch muscle, the potential role of E214k in the regulation of sepsis-induced muscle proteolysis needs to be interpreted with caution, because the results demonstrated that increased message levels were not associated with increased E214k protein levels.

Animals↗
PubMed1999

Kinetics of absorption atelectasis during anesthesia: a mathematical model.

Recent computed tomography studies show that inspired gas composition affects the development of anesthesia-related atelectasis. This suggests that gas absorption plays an important role in the genesis of the atelectasis. A mathematical model was developed that combined models of gas exchange from an ideal lung compartment, peripheral gas exchange, and gas uptake from a closed collapsible cavity. It was assumed that, initially, the lung functioned as an ideal lung compartment but that, with induction of anesthesia, the airways to dependent areas of lung closed and these areas of lung behaved as a closed collapsible cavity. The main parameter of interest was the time the unventilated area of lung took to collapse; the effects of preoxygenation and of different inspired gas mixtures during anesthesia were examined. Preoxygenation increased the rate of gas uptake from the unventilated area of lung and was the most important determinant of the time to collapse. Increasing the inspired O2 fraction during anesthesia reduced the time to collapse. Which inert gas (N2 or N2O) was breathed during anesthesia had minimal effect on the time to collapse.

Absorption↗
PubMed1999

Adherence to highly active antiretroviral therapy.

Advances in scientific understanding of and pharmacologic therapies for HIV infection have significantly increased the potential benefits of medical regimens. Patients adherence to these regimens is an essential antecedent to therapeutic effectiveness. Nursing interventions to improve adherence target the patient, the clinician, and the regimen.

Anti-HIV Agents↗
PubMed1998

Risk factors for HIV seropositivity in a sample of drug users in drug treatment in Ho Chi Minh City, Vietnam.

The article describes drug use behaviors, AIDS knowledge, risks for HIV infection, and HIV seroprevalence in drug users entering rehabilitation in Ho Chi Minh City, Vietnam. A cross-sectional, descriptive survey of all new entrants to a residential drug treatment center was conducted with linked HIV serology between July 1 and July 14, 1995. A total of 105 subjects participated: 101 men and 4 women. HIV serostatus was available for 88 subjects. Forty-seven percent (41 of 88 subjects) were HIV-positive. Median age of the subjects was 38 years. Mean length of injection drug use was 13.2 years (range, 1-27 years). The primary drug of injection was opium (96%), although 59% of subjects also injected "Western" drugs such as sedatives or tranquilizers. Eighty-two percent (86 of 105 subjects) correctly answered at least 7 of 10 AIDS knowledge questions, and only 28% (27 of 97 subjects) reported any needle sharing in the last 5 years. Seropositivity was associated with a history of previous treatment for drug abuse (p = 0.002), longer history of injecting drugs (p = 0.003), use of Western drugs (p = 0.03), and higher educational level (p = 0.05). Multivariate analysis found that the independent predictors of HIV seropositivity were history of previous treatment for drug abuse (p = 0.06) and longer history of injecting drugs (p = 0.05). Despite low levels of self-reported needle sharing and high levels of AIDS knowledge, HIV seroprevalence was high in this sample. The potential for epidemic spread of HIV in Vietnamese drug users is substantial. Risk-reduction programs and intense AIDS education projects targeting the population of drug users are necessary to control the AIDS epidemic in Vietnam.

Adult↗
PubMed1998

IGF-I stimulates protein synthesis but does not inhibit protein breakdown in muscle from septic rats.

Sepsis is associated with reduced protein synthesis and increased protein degradation in skeletal muscle. We examined the effects of insulin-like growth factor I (IGF-I) on protein synthesis and breakdown in muscles from nonseptic and septic rats. Sepsis was induced by cecal ligation and puncture; control rats were sham operated. Extensor digitorum longus muscles were incubated in the absence or presence of IGF-I at concentrations ranging from 100 ng/ml to 10 micrograms/ml. Total and myofibrillar protein breakdown rates were measured as net release of tyrosine and 3-methylhistidine, respectively. Protein synthesis was determined by measuring incorporation of [U-14C]phenylalanine into protein. IGF-I stimulated protein synthesis in a dose-dependent fashion in muscles from both sham-operated and septic rats, with a maximal effect seen at a hormone concentration between 500 and 1,000 ng/ml. IGF-I inhibited total and myofibrillar protein breakdown in muscles from sham-operated rats, whereas in muscles from septic rats, IGF-I had no effect on protein breakdown, even at high concentrations. The results suggest that protein breakdown in skeletal muscle becomes resistant to IGF-I during sepsis and that this resistance reflects a postreceptor defect.

Animals↗
PubMed1997

The effect of early versus late fasciotomy in the management of extremity trauma.

BACKGROUND: Recent reports have demonstrated an increase in the number of complications associated with delayed timing of fasciotomy for trauma. This study examines the effectiveness of early (less than 12 hours) versus late (more than 12 hours) fasciotomy in the injured extremity. METHODS: This is a retrospective review of 88 patients undergoing fasciotomy for extremity trauma admitted to the University of Cincinnati from January 1990 through December 1995. Records were reviewed for demographics, compartment pressures, time and type of fasciotomy, complications, limb salvage, and mortality. Statistical analysis was determined with chi-squared, multivariant regression analysis, and Student's t test with significance at p less than 0.05. RESULTS: Sixty-one (69%) patients had fasciotomy performed before 12 hours and twenty-seven (31%) after 12 hours. Although the rates of infection differed significantly between the two groups (7.3% for early versus 28% for late), the rates of limb salvage and neurologic sequelae were similar. Age, mechanism, shock, associated injuries, and time to fasciotomy were not predictive of complications. CONCLUSIONS: Fasciotomy for trauma is most efficacious when performed early. However, when performed late, it results in similar rates of limb salvage as compared with early fasciotomy but at the increased risk of infection. These results support aggressive use of fasciotomy in extremity trauma regardless of time of diagnosis.

Adult↗
PubMed1994

Anal and cervical human papillomavirus infection and risk of anal and cervical epithelial abnormalities in human immunodeficiency virus-infected women.

OBJECTIVE: To determine the prevalence of anal and cervical infection with human papillomavirus (HPV) and cytologic abnormalities and to examine the relation among HPV infection, cytologic abnormalities, and human immunodeficiency virus (HIV) serostatus. METHODS: Anal and cervical Papanicolaou tests, HPV dot blot tests, and polymerase chain reaction (PCR) tests for HPV were performed concurrently in a cross-sectional study of 114 women enrolled in a community-based study of HIV infection. RESULTS: Cervical HPV infection was associated with HIV serostatus by both dot blot (odds ratio [OR] 4.2, 95% confidence interval [CI] 1-25) and PCR (OR 8.9, 95% CI 3.2-27). Anal HPV infection was twice as frequent as cervical and also was associated with HIV by dot blot (OR 2.5, 95% CI 0.9-7) and PCR (OR 2.6, 95% CI 1.03-6.8). Eleven percent (11 of 96) of cervical cytologies were abnormal and were associated with HIV (OR 6.1, 95% CI 1.2-60.5). Fourteen percent (15 of 109) of anal cytologies were abnormal and were associated with HIV (OR 3.4, 95% CI 0.9-15.5). Among HIV-seropositive women, epithelial abnormalities were associated with lower mean CD4+ cell counts when HPV DNA was detected by dot blot at either the cervix (P = .04) or anus (P = .009). Independent predictors for cervical epithelial abnormalities were HPV DNA positivity by dot blot (OR 32.1, 95% CI 2.9-353.9) and positive HIV serostatus with CD4+ cell count below 250 cells/mm3 (OR 126.8, 95% CI 7.5-2132.6). CONCLUSIONS: Human papillomavirus-associated epithelial abnormalities are associated with immune suppression among HIV-infected women. Anal HPV infection and disease is at least as common as cervical infection and disease among HIV-seropositive women.

Adult↗
PubMed1993

A marine natural product, patellamide D, reverses multidrug resistance in a human leukemic cell line.

A cyclic octapeptide (patellamide D) isolated from the marine tunicate, Lissaclinum patella, acts as a resistance-modifying agent in the multidrug resistant CEM/VLB100 human leukemic cell line. A three-day microculture tetrazolium proliferation assay was used to determine the 50% inhibitory concentration (IC50) for vinblastine, colchicine and adriamycin and calculate the degree of resistance modulation. Patellamide D at 3.3 microM was compared with 5.1 microM verapamil in modulating drug resistance in vitro. The IC50 for vinblastine was reduced from 100 ng/ml to 1.5 ng/ml in the presence of patellamide D or to 2.1 ng/ml when exposed to verapamil. Colchicine cytotoxicity was enhanced only 1.4-fold by verapamil, as compared with 2.8-fold using patellamide D (IC50 was reduced from 140 ng/ml to 100 ng/ml or 50 ng/ml). Adriamycin toxicity was reduced from IC50 > 1000 ng/ml to 110 ng/ml and 160 ng/ml when coexposed to patellamide D and verapamil, respectively. Our results indicate that patellamide D acts as a selective antagonist in multidrug resistance and stresses the importance of investigating marine-derived compounds as a potential new source for modulators of the drug-resistance phenotype.

Amino Acid Sequence↗
PubMed1993

The effect of mainstream and sidestream cigarette smoke exposure on oxygen defense mechanisms of guinea pig erythrocytes.

We have studied the effects of short-term exposure of guinea pigs to cigarette smoke under both mainstream (MS) and sidestream (SS) conditions on the activities of major antioxidant enzymes and lipid peroxidation potential of erythrocytes. The smoke-exposed groups had an increase in the activity of superoxide dismutase (SOD), a decrease in the activities of glutathione peroxidase (GSH-Px) and NADPH generating enzymes, and no change in the activity of catalase. Furthermore, there was a significant increase in the in vitro lipid peroxidation potential of erythrocytes in both MS- and SS-exposed groups. However, the lipid peroxidation potential was higher in the MS-exposed group than that in the SS-exposed group.

Animals↗
PubMed1993

The mother-child relationship in the HIV-1 positive family.

Qualitative data (N = 80) from a larger study of HIV-1 positive mothers have revealed mother-child relationships, that is, a strong attachment along with a bond of secrecy. The relationship is described as a strong attachment along with a bond of secrecy. Children are perceived by the mothers as sources of support as well as sources of stress in the relationship. We conclude that practice and policy decisions concerning HIV-1 positive mothers should include emphasis on maintaining the health of the mother-child dyad, providing respite to mothers and providing support for future planning.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Methadone maintenance treatment and HIV type 1 seroconversion among injecting drug users.

This study examined whether methadone maintenance treatment decreases drug injection enough to significantly limit HIV-1 transmission among injection drug users (IDU). When HIV-1 seroconversion status among prospectively followed methadone maintenance clients was analyzed by treatment retention, 1/56 (2%) of those who remained continuously in treatment seroconverted while 8/42 (19%) of those whose methadone treatment was interrupted seroconverted. When controlled for length of follow up, the difference in seroconversion rate was not statistically significant. Subjects in continuous treatment had a seroconversion rate of 0.7 per 100 person years (95% Confidence Interval [CI] = 0.1, 5.3) and those with interrupted treatment a rate of 4.3 per 100 person years (95% CI = 2.2, 8.6). Subjects in continuous treatment reported less needle sharing (p less than 0.0002), fewer needle sharing partners (p less than 0.002), fewer sexual partners (p less than 0.03), and were more likely to be women (p less than 0.01). These data indicate the need for larger studies to evaluate both client and drug treatment program characteristics which might concomitantly increase treatment retention and decrease HIV-1 risk.

Adult↗
PubMed1992

The epidemiology, clinical manifestations and health-maintenance needs of women infected with HIV.

The growing epidemic of HIV infection poses a serious threat to women's health in the United States and abroad. In the United States, HIV disproportionately affects African-American and Hispanic-American woman. Primary care providers will be faced with an increasing need to provide counseling and clinical services to these women. It is not yet clear whether gender affects the natural history of HIV infection; differences in survival rates may reflect lack of access to care rather than true biologic differences. Opportunistic infections among women with HIV infection are similar to those found among men with AIDS who use injection drugs. Unique expressions of HIV disease associated with women's reproductive tracts include persistent vaginal candidiasis, human papillomavirus infections and cervical dysplasia. Women with HIV infection should receive thorough gynecologic screening, including Pap smears, every six months. Women who know they are HIV positive may choose to become pregnant; these clients require extensive prenatal care and state-of-the-art HIV management.

HIV Infections↗
PubMed1992

Women in the HIV epidemic.

In the United States, the majority of women with HIV/AIDS are women whose lives have been touched by injection drug use--their own or that of their sexual partners. The pattern of opportunistic infections in women is more similar to that of injection drug users than that of homosexual men. Specific complications associated with a woman's reproductive tract include persistent Candida vaginitis, human papillomavirus infections, cervical dysplasias, and, possibly, pelvic inflammatory disease. Childbearing decisions for women with HIV infection are complex and culturally mediated. Meeting the challenge of providing high quality services to women with HIV infection requires major changes in the service delivery system.

Female↗