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Biomedical subjects

C Lewis

Publications and source records attributed to C Lewis.

At least 73 records · Page 4Linked to original sources
PubMed1999

Hepatitis C virus and lichen planus: A case-control study of 340 patients.

Lichen planus (LP) has been associated with liver disease, particularly hepatitis C virus (HCV) infection, in several studies to date. Most of these reports, especially the larger series, were conducted in Europe. In addition, the type of LP associated with HCV was reported to be oral LP in most studies. We conducted a case-control study in a US metropolitan population known to have a low seroprevalence of HCV infection to explore the impact of geography and endemicity of HCV on the association between cutaneous LP and HCV. The study comprised 340 patients with cutaneous LP (as case ) against 577 patients with psoriasis (as control-1 ). Hepatitis antibody titers and liver function abnormalities were our main outcome measures. Prevalence of HCV antibody among 149,756 regional volunteer blood donors (as control-2 ) was also used for comparison. Twelve (55%) of 22 patients with LP tested for HCV were antibody positive. This was significantly higher than 25% of 40 psoriasis patients tested for HCV antibody (P =.04) or than 0.17% of blood donors tested for HCV antibody (P < 10(-5)). Thus a small but significant percentage of US patients with cutaneous LP had HCV antibody. Because LP may be the first presentation of HCV infection, it is important for clinicians to actively look for such infection in patients with LP.

Case-Control Studies↗
PubMed1999

Porphyria cutanea tarda and hepatitis C virus: a case-control study and meta-analysis of the literature.

BACKGROUND: Porphyria cutanea tarda (PCT) and hepatitis C virus (HCV) infection have been associated in several reports with the prevalence of HCV exhibiting considerable regional variation. However, most reports were confounded by selection bias and a regional prevalence of HCV in the populations studied. In the United States, only a few cases of this association have been reported to date. OBJECTIVE: We concluded a study to evaluate the association between PCT and HCV in a US population. We used a case-control study design to control the systemic error that may occur during a selecting process or sampling procedure. METHODS: We reviewed the medical records of Wishard Memorial Hospital, a county hospital serving metropolitan Indianapolis, Indiana, to perform a retrospective case-control study of 26 patients with PCT (as case) against 149,756 regional volunteer blood donors (as control-1) and 51 patients receiving methotrexate for psoriasis (as control-2). HCV antibody titers and other liver abnormalities were our main outcome measures. We then performed a weighted meta-analysis of 17 reports that had at least 17 patients in their study populations. RESULTS: Sixteen (94%) of 17 PCT patients tested for HCV were antibody positive. Among blood donors, only 255 or 0.17% were HCV antibody positive (P < 10(-5), two-sided chi-square test). Of 5 psoriasis patients tested for HCV, none were HCV antibody positive (P = .0002, two-sided Fisher's exact test). For geographic comparison, meta-analysis of the literature demonstrated a varying regional prevalence of HCV in PCT patients as follows: Northern Europe 17%, Australia/New Zealand 20%, and Southern Europe 65%. CONCLUSION: Although a marked geographic variation was found in the worldwide prevalence of HCV in PCT patients, a very large percentage of US patients with PCT had HCV infection. Our results emphasize the need for clinicians to actively look for HCV in patients with PCT.

Australia↗
PubMed1999

Career structures for South Australian nurses: developing a research agenda.

Career structure models are central to the organisation of the work of professionals like nurses, to their remuneration and other forms of recognition, and for the organisation of employing institutions. It has been little more than a decade since the implementation of a career structure model for nurses in South Australia in 1986-7. Since that time a number of changes to the profession, and to the health care system more generally, have resulted in ad hoc adaptations to, and sometimes an erosion of, the career structure as originally envisioned. As we approach the new millennium, an assessment and evaluation of the efficacy of the SA career structure in meeting the professional needs of nurses and their employing organisations is both timely and necessary. This paper provides the historical background to the development of the SA career structure, and highlights some of the major issues that have emerged as problematic since implementation. The paper then identifies some issues that might contribute towards guiding a more systematic approach to the re-appraisal of nurses' career structures.

Career Mobility↗
PubMed1999

Acquired amegakaryocytic thrombocytopenia treated with allogeneic BMT: a case report and review of the literature.

Despite recent advances in understanding the biology of thrombopoiesis, autoimmune thrombocytopenia caused by inhibition of megakaryocytic precursors, remains a treatment dilemma. We report a case of a 43-year-old female who developed amegakaryocytic thrombocyto- penia refractory to intravenous immunoglobulin (IVIG), prednisone, cytoxan and vincristine. She was subsequently treated with myeloablative chemotherapy (busulfan and cyclophosphamide) followed by allogeneic bone marrow transplant from a 6/6 HLA-matched sibling. The patient is currently more than 1 year after transplant with complete donor chimerism and restoration of normal thrombopoiesis. A review of the literature shows that the clinical syndrome known as amegakaryocytic thrombocytopenia represents a heterogeneous group of disorders, and clinical experience with immunosuppression varies. Appropriate initial treatment for these patients requires immunosuppressive agents, including antithymocyte globulin (ATG) for steroid refractory disease. However, in the case of symptomatic patients who have an appropriate sibling donor, early hematopoietic progenitor cell transplant, even before administration of ATG, may be necessary. Further studies are needed to better define the pathogenesis and mechanism of this heterogeneous disorder before more definitive treatment algorithms can be established.

Adult↗
PubMed1999

A comparison of polymerase chain reaction and phenotyping for rapid speciation of enterococci and detection of vancomycin resistance.

This study aimed to ascertain the ability of the microbiology laboratory to detect and identify catalase-negative Gram-positive cocci with particular reference to vancomycin-resistant enterococci (VRE). Twenty-seven reference strains and 42 prospectively collected catalase-negative Gram-positive cocci were screened by agar dilution breakpoint susceptibility and linked biochemical methods in routine use. Ability to speciate organisms was then compared using: (i) a multiplex polymerase chain reaction, designed to detect gene sequences specific to Enterococcus faecalis and E. faecium, and vancomycin resistance (van) genes; (ii) a commercial "API 20 strep" (iii) an algorithm using individual tests from a commercial API 20 strep strip; and (iv) the same algorithm utilising traditional phenotyping methods. All vancomycin resistant catalase-negative Gram-positive cocci were detected by an agar dilution screening plate containing 4 micrograms/ml of vancomycin. Polymerase chain reaction (PCR) detected all enterococci with van genes, speciated all vancomycin-sensitive E. faecalis and E. faecium isolates and excluded non-enterococcal vancomycin-resistant catalase-negative Gram-positive cocci. Algorithm-based methods speciated 41 of the 42 study isolates (98%). The API 20 strep correctly identified only 25 (60%) of these organisms, 38 of which were vancomycin-sensitive E. faecalis. VRE are detected by current screening methods for vancomycin-resistant catalase-negative Gram-positive cocci in this laboratory. API 20 strep, currently used to speciate catalase-negative Gram-positive cocci, is less reliable and should be replaced. Algorithm-based phenotyping by either method tested is more reliable for speciation than API 20 strep in its recommended form. Compared to the other methods tested, PCR is a rapid, accurate and inexpensive method of detecting and speciating vancomycin-resistant enterococci and it provides important extra information impacting on clinical therapy and infection control.

Algorithms↗
PubMed1999

Molecular characterization of CTNS deletions in nephropathic cystinosis: development of a PCR-based detection assay.

Nephropathic cystinosis is an autosomal recessive disorder that is characterized by accumulation of intralysosomal cystine and is caused by a defect in the transport of cystine across the lysosomal membrane. Using a positional cloning strategy, we recently cloned the causative gene, CTNS, and identified pathogenic mutations, including deletions, that span the cystinosis locus. Two types of deletions were detected-one of 9.5-16 kb, which was seen in a single family, and one of approximately 65 kb, which is the most frequent mutation found in the homozygous state in nearly one-third of cystinotic individuals. We present here characterization of the deletion breakpoints and demonstrate that, although both deletions occur in regions of repetitive sequences, they are the result of nonhomologous recombination. This type of mechanism suggests that the approximately 65-kb deletion is not a recurrent mutation, and our results confirm that it is identical in all patients. Haplotype analysis shows that this large deletion is due to a founder effect that occurred in a white individual and that probably arose in the middle of the first millenium. We also describe a rapid PCR-based assay that will accurately detect both homozygous and heterozygous deletions, and we use it to show that the approximately 65-kb deletion is present in either the homozygous or the heterozygous state in 76% of cystinotic patients of European origin.

Alleles↗
PubMed1999

Epidemiology of device-associated infections related to a long-term implantable vascular access device.

OBJECTIVE: To examine risk factors for, and determine the incidence of, device-associated infections among patients with an implantable vascular access device. SETTING: Grady Health System, including a 1,000-bed, inner-city, public, teaching hospital and human immunodeficiency virus (HIV), oncology, and sickle cell clinics in Atlanta, Georgia. PATIENTS: 123 consecutive patients who received a PAS-Port implantable venous access device between January 1 and June 30, 1995. DESIGN: Retrospective cohort study with follow-up > or = 1 year following device implantation. RESULTS: Underlying illnesses included HIV infection in 66 patients (median CD4 count, 24.4 cells/mm3), malignancy in 51, and sickle cell disease in 6. Mean age of patients was 43.7 years, 50% were male, and 74% were black. Thirty-one (25%) of 123 patients developed a primary or device-associated bloodstream infection (BSI), and 3 of the 31 patients experienced two separate episodes of infection. The overall rate of infection was 1.23 primary BSIs per 1,000 device days. Patients with cancer had a lower rate of infection than those with HIV infection, but the difference was not statistically significant (0.96 vs 1.50 BSIs/1,000 device days; relative risk, 0.58; 95% confidence interval, 0.27-1.26). Subgroup analysis of patients with different malignancies indicated that infection rates differed according to type of cancer, and there was a trend for heterogeneity across the different cancer strata (P=.06). Gram-positive pathogens accounted for 60% of the pathogens recovered. Six (19%) of 31 patients who developed an infection did so within the first 14 days after implantation. In 11 (32%) of the 34 BSIs, the port required removal; two patient deaths were attributed to device-associated bacteremias (0.072 deaths/1,000 device days). CONCLUSIONS: Approximately one fourth of patients who had a vascular access device implanted developed a primary BSI, but the overall infection rate (per 1,000 device days) was relatively low, even among those with HIV infection. Primary BSI rates in patients with vascular access devices appeared to differ according to the specific underlying illness.

Adult↗
PubMed1999

Differential patterns of spinal sympathetic outflow involving a 10-Hz rhythm.

Time and frequency domain analyses were used to examine the changes in the relationships between the discharges of the inferior cardiac (CN) and vertebral (VN) postganglionic sympathetic nerves produced by electrical activation of the midbrain periaqueductal gray (PAG) in urethan-anesthetized, baroreceptor-denervated cats. CN-VN coherence and phase angle in the 10-Hz band served as measures of the coupling of the central oscillators controlling these nerves. The 10-Hz rhythm in CN and VN discharges was entrained 1:1 to electrical stimuli applied to the PAG at frequencies between 7 and 12 Hz. CN 10-Hz discharges were increased, and VN 10-Hz discharges were decreased when the frequency of PAG stimulation was equal to or above that of the free-running rhythm. In contrast, stimulation of the same PAG sites at lower frequencies increased, albeit disproportionately, the 10-Hz discharges of both nerves. In either case, PAG stimulation significantly increased the phase angle between the two signals (VN 10-Hz activity lagged CN activity); coherence values relating their discharges were little affected. However, the increase in phase angle was significantly more pronounced when the 10-Hz discharges of the two nerves were reciprocally affected. Importantly, partialization of the phase spectrum using the PAG stimuli did not reverse the change in CN-VN phase angle. This observation suggests that the increase in the CN-VN phase angle reflected changes in the phase relations between coupled oscillators in the brain stem rather than the difference in conduction times to the two nerves from the site of PAG stimulation. In contrast to the effects elicited by PAG stimulation, stimulation of the medullary lateral tegmental field induced uniform increases in the 10-Hz discharges of the two nerves and no change in the CN-VN phase angle. Our results demonstrate that changes in the phase relations among coupled brain stem 10-Hz oscillators are accompanied by differential patterns of spinal sympathetic outflow. The reciprocal changes in CN and VN discharges produced by PAG stimulation are consistent with the pattern of spinal sympathetic outflow expected during the defense reaction.

Animals↗
PubMed1999

Two-year follow-up of AIDS education programs for impoverished women.

The long-term effects of two culturally competent AIDS education programs with different content on the risk behavior and AIDS-related knowledge of 410 homeless African American women 2 years after program completion were examined. Participants were members of a larger cohort of impoverished African American and Latina women recruited in Los Angeles from 1989 to 1991. Of a subsample of 527 African American women selected randomly for a 2-year follow-up interview, 410 (78%) were located and agreed to participate. Women participating in both AIDS education programs reported reduced HIV risk behaviors and demonstrated greatly improved AIDS knowledge at 2-year follow-up (p < .001). Women in a specialized program were less likely than those in a traditional program to report noninjection drug use at 2 years. Women in the traditional program had significantly better AIDS knowledge at follow-up (p < .001). These findings suggest that educational programs can produce sustained benefits among impoverished women.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Chemoprotectants: a review of their clinical pharmacology and therapeutic efficacy.

Dose-limiting toxicity secondary to antineoplastic chemotherapy is due to the inability of cytotoxic drugs to differentiate between normal and malignant cells. The consequences of this may include impairment of patient quality of life, because of toxicity, and reduced tumour control because of the inability to deliver adequate dose-intensive therapy against the cancer. Specific examples of toxicity against normal tissues include cisplatin-related neurotoxicity and nephrotoxicity, myelotoxicity secondary to treatment with alkylating agents and carboplatin, oxazaphosphorine-induced haemorrhagic cystitis, and cumulative dose-related cardiac toxicity secondary to anthracycline treatment. Chemoprotectants have been developed as a means of ameliorating the toxicity associated with cytotoxic agents by providing site-specific protection for normal tissues, without compromising antitumour efficacy. Clinical trials with toxicity protectors must include sufficient dose-limiting events for study, and assessment of both toxicity (allowing for measurement of efficacy of protection) and antitumour effect. Several chemoprotective compounds have now been extensively investigated, including dexrazoxane, amifostine, glutathione, mesna and ORG 2766. Dexrazoxane appears to complex with metal co-factors including iron, to reduce the incidence of anthracycline-induced cardiotoxicity, allowing the delivery of higher cumulative doses of anthracyclines without the expected consequence of cardiomyopathy. Numerous studies have demonstrated that sulfur-containing nucleophiles, including amifostine, glutathione, and mesna can specifically bind cisplatin- or alkylating agent-generated free radicals or alkylating agent metabolites to reduce the incidence of cisplatin-associated neurotoxicity and nephrotoxicity, or alkylating agent-associated myelosuppression and urothelial toxicity. These studies, in the majority of instances, have not revealed any evidence of reduction in antitumour efficacy. Further randomised trials are required to identify the optimal role of chemoprotectants when used alone or in combination with other toxicity modifiers including haemopoietic growth factors.

Adrenocorticotropic Hormone↗
PubMed1998

Rural epidemiology: insights from a rural population laboratory.

To study the epidemiology of rural populations in the context of contemporary issues in public health, a population laboratory (Health Census '89) was established in Otsego County, New York, by the Research Institute of the M.I. Bassett Hospital, affiliated with the Columbia University School of Public Health. Such a laboratory is needed because of an apparent lag in positive health indices in rural populations across the United States, resulting in rates of chronic diseases, such as coronary heart disease, for which rural areas now exceed urban ones. This was confirmed for Otsego County by the survey Health Census '89, the foundation of a rural population laboratory, in which all residents were enumerated and characterized as to their prevalent diseases, health behaviors, use of preventive services, and environmental exposures. Heart disease, cancer, and diabetes mellitus rates were found to exceed average rates for US urban areas, while the data on preventive health behaviors suggest this is a population of "late adopters." The survey, conducted in 1989, had an 86.6% response rate, and enumerated 17,147 households and 44,406 persons. The authors discuss adults aged 17-64 years, 58 percent of the total census (n=25,614). Sharp gradients in disease prevalence, risk factors, and utilization of preventive services were observed across educational strata. Data from Health Census '89 were used as the basis for a successful community intervention program, which targeted identified high risk groups. Rural populations are excellent settings for community interventions, offering laboratories where new strategies of risk reduction and provision of preventive services might be tested.

Adolescent↗
PubMed1998

Differential rescue of visceral and cardiac defects in Drosophila by vertebrate tinman-related genes.

tinman, a mesodermal NK2-type homeobox gene, is absolutely required for the subdivision of the early Drosophila mesoderm and for the formation of the heart as well as the visceral muscle primordia. Several vertebrate relatives of tinman, many of which are predominately expressed in the very early cardiac progenitors (and pharyngeal endoderm), also seem to promote heart development. Here, we show that most of these vertebrate tinman-related genes can readily substitute for Drosophila tinman function in promoting visceral mesoderm-specific marker gene expression, but much less in promoting cardiac-specific gene expression indicative of heart development. In addition, another mesodermal NK2-type gene from Drosophila, bagpipe, which is normally only needed for visceral mesoderm but not heart development, cannot substitute for tinman at all. These data indicate that the functional equivalence of the tinman-related subclass of NK2-type genes (in activating markers of visceral mesoderm development in Drosophila) is specific to this subclass and distinct from other homeobox genes. Despite the apparent overall conservation of heart development between vertebrates and invertebrates, the differential rescue of visceral mesoderm versus heart development suggests that some of the molecular mechanisms of organ formation may have diverged during evolution.

Animals↗
PubMed1998

Removal of a Norplant implant located near a major nerve using interventional radiology-digital subtraction fluoroscopy.

Norplant implants can be removed easily, if inserted properly. When they are inserted deeply and can not be palpated, or if they are located close to the neurovascular structures of the upper arm, radiological guidance may be needed to locate and remove the implants without causing injury to the surrounding vital structures. Digital subtraction fluoroscopic guidance is helpful in removing deeply located contraceptive implants and those that are close to the neurovascular structures, where blind removal may result in injury to those structures. We describe a case in which an implant that was located close to a major nerve near the axilla was removed under digital subtraction fluoroscopic guidance.

Adult↗
PubMed1998

Help-seeking decisions among men with impotence.

OBJECTIVES: There is a paucity of valid contemporary data concerning the proportion of impotent men who seek treatment. The aim of this study was to determine the proportion of impotent men who sought treatment, from whom they sought treatment, and their reasons for seeking or not seeking treatment. METHODS: A self-administered survey of 5198 randomly selected men between 50 and 76 years old, living in four rural counties in central New York State, was used. RESULTS: The sample included 649 men who reported having experienced impotence in the 6 months preceding the study period (November 1996 to June 1997). The mean age of these men and mean duration of impotence were 64.5+/-7.2 and 4.9+/-4.6 years, respectively. Two hundred five men (31.6%) had sought treatment, 432 (66.6%) had not, and 12 (1.8%) neglected to answer the question. Most first consulted with either their primary care provider (44.7%) or a urologist (40.7%). Among those who had sought treatment, 36.3% were satisfied, 48.4% were dissatisfied, and 15.2% were neither satisfied nor dissatisfied with the results. The primary reasons for seeking treatment were to improve their self-esteem (44.8%), awareness of a new treatment (33.4%), partner insistence ( 11.3%), and coverage by their health insurance (10.4%). The reasons for not seeking treatment were embarrassment (29.8%), ignorance or misinformation (45.2%), and lack of affordability (25.0%). CONCLUSIONS: Despite increased availability of effective treatment, most men with impotence do not seek treatment, and among those who do, only 36.3% are satisfied with the results.

Aged↗