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Biomedical subjects

R Wood

Publications and source records attributed to R Wood.

At least 145 records · Page 8Linked to original sources
PubMed1993

Quantification and comparison of HIV-1 proviral load in peripheral blood mononuclear cells and isolated CD4+ T cells.

HIV proviral load was determined by quantitative DNA polymerase chain reaction (PCR) in peripheral blood mononuclear cells (PBMC) and lymphocyte subsets isolated by cell sorter. Provirus measured in PBMC, when expressed as HIV copy number per million CD4+ cells, resulted in values which approximated those obtained from sorted CD4+ T lymphocytes. A cross sectional analysis of HIV proviral load in CD4+ T cells from 25 previously untreated and 30 zidovudine-treated seropositive patients with CD4+ T-cell counts between 25 and 802/mm3 demonstrated HIV copy numbers ranging from 1 copy per 10,000 cells in early disease to 1 copy per 10 cells in advanced disease. HIV proviral load can be rapidly assayed by PCR to give a reproducible value which varies over a 1,000-fold range and is positively correlated with cell infectivity as measured by a quantitative micrococulture assay. A less technically demanding assay using PBMC as substrate can give similar results to those obtained with sorted CD4+ T cells.

Cell Count↗
PubMed1992

Initial combination chemotherapy with cisplatin, methotrexate and vinblastine in locally advanced transitional cell carcinoma--response rate and pitfalls. MRC Subgroup in Advanced Bladder Cancer (on behalf of the MRC Urological Working Party).

A total of 51 patients with locally advanced transitional cell carcinoma of the bladder were entered into a phase II study to evaluate the effect of initial cisplatin (100 mg/m2, Day 2) combined with methotrexate (30 mg/m2, Days 1 and 8) and vinblastine (4 mg/m2, Days 1 and 8). Of 44 evaluable patients, 25 (57%) achieved an objective response of their primary bladder tumour (complete response (CR): 4 patients; partial response (PR): 21 patients); 30 of the 36 patients with micturition disturbances obtained relief. Toxicity was acceptable, but dose modifications due to haematological or renal toxicity were required in 153 of the 690 drug courses. Non-protocol dose modifications were performed 45 times. The experience gained in this trial emphasises the need for improved co-operation between urologists, radiologists and clinical oncologists in such multicentre phase II studies. Difficulties were observed in adhering to dose modification rules, assessing pre-treatment tumour size (due to variation in quality of measure and in timing relative to initial transurethral resection (TUR)) and defining response to chemotherapy (due to failure to perform mandatory investigations at the right time). This study also illustrates that the accepted criteria for assessing response in the primary bladder tumour are difficult to apply in practice and that the results of any study using this indicator lesion require caution in their interpretation.

Aged↗
PubMed1992

Biological activity of paramyxovirus fusion proteins: factors influencing formation of syncytia.

The fusion (F) and hemagglutinin-neuraminidase (HN) glycoproteins of the paramyxovirus simian virus 5 (SV5) were expressed individually or coexpressed in CV-1 cells by using SV40-based vectors and recombinant vaccinia viruses. The extent of detectable fusion in a syncytium formation assay was found to be affected by the expression system used. In addition, when HN was coexpressed with F, it was found that the expression vector system influenced the contribution of HN in forming syncytia. The abilities of the SV5, human parainfluenza virus type 3, and Newcastle disease virus F glycoproteins to cause fusion, when expressed alone or coexpressed with HN, were directly compared by using the SV40-based vector system in CV-1 cells. The F proteins exhibited various degrees of fusion activity independent of HN expression, but the formation of syncytia could be enhanced to different extents by the coexpression of the homotypic HN protein.

Cell Line↗
PubMed1992

Cancer risks from arsenic in drinking water.

Ingestion of arsenic, both from water supplies and medicinal preparations, is known to cause skin cancer. The evidence assessed here indicates that arsenic can also cause liver, lung, kidney, and bladder cancer and that the population cancer risks due to arsenic in U.S. water supplies may be comparable to those from environmental tobacco smoke and radon in homes. Large population studies in an area of Taiwan with high arsenic levels in well water (170-800 micrograms/L) were used to establish dose-response relationships between cancer risks and the concentration of inorganic arsenic naturally present in water supplies. It was estimated that at the current EPA standard of 50 micrograms/L, the lifetime risk of dying from cancer of the liver, lung, kidney, or bladder from drinking 1 L/day of water could be as high as 13 per 1000 persons. It has been estimated that more than 350,000 people in the United States may be supplied with water containing more than 50 micrograms/L arsenic, and more than 2.5 million people may be supplied with water with levels above 25 micrograms/L. For average arsenic levels and water consumption patterns in the United States, the risk estimate was around 1/1000. Although further research is needed to validate these findings, measures to reduce arsenic levels in water supplies should be considered.

Animals↗
PubMed1992

Effects of a bisphosphonate on experimental periodontitis in monkeys.

Bisphosphonates have been shown to increase bone mass in estrogen-deficient patients by inhibiting osteoclast activity. The purpose of this study was to measure clinical and radiographic effects of a bisphosphonate on periodontitis development in monkeys. Twenty-seven (27) adult cynomolgus monkeys were studied. After quarantine, baseline data were obtained including plaque index, gingival index, clinical probing depth measurements, and intraoral radiographs. Standardized radiographs were analyzed for quantitative changes in bone density using a computer assisted densitometric (CADIA) system. Animals were divided into 3 groups to receive 1 of the 3 treatment agents; these agents consisted of two levels of the test drug (alendronate) and a saline placebo. Agents were injected in the saphenous vein of the lower leg every 2 weeks for 16 weeks. One week after the initiation of treatment agent injections, mandibular right molars and premolars were ligated with 3-0 silk sutures to induce periodontitis. Ligated teeth were also inoculated with Porphyromonas gingivalis to insure a significant etiologic challenge. Nonligated homologous teeth served as controls. Clinical measurements and radiographs were repeated at 8 and 16 weeks after ligation. The bisphosphonate at a concentration of 0.05 mg/kg significantly retarded the progression of periodontitis as measured by bone density changes. The higher level dose of the test drug did not differ from placebo with respect to loss of bone density. Clinical indices were not affected significantly by the test drugs. Drugs that alter bone metabolism may offer a new approach to the treatment of periodontal disease.

Alendronate↗
PubMed1992

Arthroscopic knee surgery.

Arthroscopy of the knee has become a high-volume procedure for ambulatory surgery centers. As technology advances, these procedures will become more complicated. Perioperative nurses are challenged to stay abreast of advancing technology. This article discusses the perioperative care of the client having arthroscopic knee surgery.

Ambulatory Surgical Procedures↗
PubMed1992

Association of human immunodeficiency virus and anal human papillomavirus infection among homosexual men.

BACKGROUND: A previous study of men with proctitis, proctocolitis, or enteritis showed an association of anal human papillomavirus (HPV) infection with human immunodeficiency virus (HIV) infection. Because anorectal abnormalities may confound an observed association between anal HPV DNA and HIV seropositivity, the present study was undertaken among consecutive homosexual men seeking HIV serologic testing who were unselected for anorectal symptoms. METHODS: Consecutive homosexual men underwent a standardized interview, physical examination, and collection of specimens for HIV serologic testing and detection of anal HPV DNA. RESULTS: Anal HPV DNA was detected in eight (31%) of 26 HIV-seropositive men and in 10 (8%) of 119 HIV-seronegative men (odds ratio, 5.8; 95% confidence interval, 1.1 to 30.1, adjusted for history of sexually transmitted disease, current anorectal symptoms, and age). When men with anorectal symptoms were excluded from the analysis, anal HPV DNA was detected in 27% of seropositive men compared with 8% of seronegative men (odds ratio, 4.4; 95% confidence interval, 1.4 to 13.4). There was no difference between HIV-seropositive and HIV-seronegative men with respect to distribution of type of HPV DNA. Men with group II or III and group IV HIV disease were 4.1 and 10.9 times, respectively, more likely than HIV-seronegative men to have anal HPV DNA detected. CONCLUSIONS: Because HIV-seropositive men appear to be at increased risk for the detection of anal HPV DNA, the natural course of anal HPV infection should be compared among HIV-seropositive and HIV-seronegative homosexual men.

Anus Diseases↗
PubMed1991

Colonic complications after toxic tribal enemas.

Tribal enemas obtained from traditional healers are used widely in Southern Africa for a variety of indications. Inclusion of injurious substances such as potassium dichromate may cause serious colonic and renal complications. Nine such patients, in seven of whom chromate use was confirmed, presented after a mean delay of 7.3 days. All patients had bloody diarrhoea and vomiting and three underwent major colonic resection, requiring a total of ten procedures. One patient suffered mechanical perforation of the rectum, with subsequent necrotizing fasciitis, necessitating rectal excision. Eight patients had acute renal failure and seven required dialysis. One patient died. At follow-up one patient has chronic renal failure and only three are completely well. Although local medical practitioners are aware of the problem, the challenge of preventing harmful cultural practices remains.

Acute Kidney Injury↗
PubMed1991

Goal setting and the differential influence of self-regulatory processes on complex decision-making performance.

The effects of goal setting and cognitive self-regulatory processes were examined on a highly complex task, a managerial decision-making simulation. It was hypothesized that the presence vs. absence of a specific performance goal would moderate the strength of relations between performance and 2 self-regulatory processes: self-efficacy judgments and self-evaluative reactions. Ss received either a moderately or extremely difficult task goal, or no specific goal. Self-regulatory processes were assessed after an initial trial block. Regression analyses revealed that, as predicted, both self-regulatory processes more strongly affected performance when Ss received a specific goal. Contrary to earlier findings obtained with simple activities, dissatisfaction with prior outcomes impaired performance. Ss who were dissatisfied with past attainments exerted much decision effort but adopted inferior task strategies that produced poorer results.

Analysis of Variance↗
PubMed1991

Effects of immunization with Porphyromonas gingivalis and Prevotella intermedia on progression of ligature-induced periodontitis in the nonhuman primate Macaca fascicularis.

The nonhuman primate (Nhp) has proven to be a useful model of human periodontitis. This study describes the immunological characteristics of this model and the ability of active immunization to interfere with ecological changes in the microbiota and its associated disease symptoms. Nhps were parenterally immunized with whole-cell antigens of Porphyromonas gingivalis and Prevotella intermedia. The immunization elicited an approximate 2-log increase in serum immunoglobulin G (IgG), IgM, and IgA isotype antibody that was highly specific for these immunogens. Postimmunization and postligation, there was minimal change in the levels of specific antibody. P. gingivalis immunization significantly inhibited the emergence of this species during disease progression. In contrast, induction of anti-P. intermedia antibody had a minimal effect on this species within the subgingival plaque. Plaque indices showed few changes that could be attributed to active immunization. Both bleeding on probing and loss of attachment were higher in ligated sites of immunized animals than in the placebo-treated group. A significant increase in bone density loss was observed in the ligated teeth from immunized versus control animals. These findings indicate that active immunization of Nhps can elicit a substantial systemic immune response; however, while this response may effect the emergence of an individual microorganism, it appears that other ecological considerations are critical in disease progression. It is also possible that the induction of a broad-based immune response to multiple bacterial antigens can result in increased disease, potentially associated with hypersensitivity reactions to the bacteria in the subgingival plaque.

Animals↗
PubMed1991

MCC, a candidate familial polyposis gene in 5q.21, shows frequent allele loss in colorectal and lung cancer.

MCC is a gene located within human chromosome band 5q.21 that shows somatically acquired mutations in colorectal cancer, and may be identical to the gene responsible for inheritance of familial adenomatous polyposis. Here we demonstrate that alleles contiguous with or within MCC are deleted in a high proportion of sporadic colorectal carcinomas. Of 106 carcinomas that were informative concurrently at close-flanking sites both centromeric and telomeric to MCC, 41.5% showed acquired allele loss contiguous with MCC. Evidence is presented to show that the true frequency of loss of MCC alleles is higher still. In contrast, allele losses in chromosome 5 that were incompatible with involvement of MCC were very rare (2% of a total series of 201 informative tumours). Interstitial deletion was the commonest mechanism of allele loss, and L5.71-3, a probe known to include coding sequences of MCC, marks the most consistently deleted site. Moreover mapping of chromosome breakpoints with six probes within 5q.21 sited the common critical deletion in a 2.5 Mb region which included L5.71-3. However use of L5.71-3 itself suggested that critical deleted regions may lie on either side of the probed sequence. The simplest explanation for this unexpected finding is that MCC itself is the essential deleted gene, the lost exons lying sometimes centromeric to, sometimes telomeric to and occasionally within the region detected by L5.71-3. Tumours in which MCC-related alleles were lost by interstitial deletion were in general larger than those with other mechanisms of acquired homozygosity (e.g. mitotic recombination), but there were no other obvious associations with clinicopathological features. Between 20% and 25% of lung cancers also showed acquired allele losses contiguous with MCC. The significance of this observation is still to be determined, as lung tumours show allele losses at many other sites, but the specificity of the probes used in this study does establish that the 5q.21 losses in these tumours are compatible with involvement of MCC.

Adenomatous Polyposis Coli↗
PubMed1991

Long-term follow-up of cemented total hip arthroplasty in rheumatoid arthritis.

Seventy-five primary cemented total hip arthroplasties (THAs) were performed in 53 patients with rheumatoid arthritis and juvenile rheumatoid arthritis. All patients were followed for an average of 7.4 years, unless their prosthetic hips failed before that time. Clinical evaluation was based on a 10-point maximum rating scale, and ratings for pain, walking, function, and activity improved from preoperative values to the most recent follow-up examination. Revision THA was performed for aseptic acetabular loosening in four hips, and femoral loosening in one hip. Sepsis occurred in another four hips. Complications of wound healing occurred in 14 hips. Roentgenographic evidence of loosening was seen in six acetabular components, in three femoral components, and in the femoral and acetabular component of one hip; none of these hips have as yet required revision THA. The Kaplan-Meier survivorship analysis revealed a 93% survival probability at seven years, which fell to 77% at 12 years in these patients. A trend was that younger, larger patients had increased failure and component loosening rates. Cemented primary THA has been a satisfactory operation in the rheumatoid patient. The relatively high rate of wound healing problems and sepsis may be due to the systemic immune nature of rheumatoid arthritis; however, 25% of these prosthetic hips either failed or are at risk for future failure. Thus, improved techniques are still necessary to increase the long-term success of THA in the rheumatoid patient.

Adolescent↗
PubMed1990

Acute dichromate poisoning after use of traditional purgatives. A report of 7 cases.

Seven cases of dichromate poisoning after the use of purgative solutions obtained from nyanga (traditional township healers) are reported. The patients all presented in established renal failure requiring dialysis, and all had abnormal liver function tests. One patient who took dichromate orally died from massive gastro-intestinal haemorrhage. Six patients took dichromate solutions as rectal enemas, 2 were left with impaired renal function and 1 required a permanent colostomy as a result of extensive peri-anal necrosis. The clinical presentation of acute renal failure, gastro-intestinal haemorrhage and hepatocellular dysfunction should alert the physician to the possibility of dichromate poisoning. The diagnosis, management and the role of dialysis in dichromate poisoning are reviewed.

Adult↗