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Biomedical subjects

J C Neff

Publications and source records attributed to J C Neff.

At least 19 recordsLinked to original sources
PubMed2006

The impact of boreal forest fire on climate warming.

We report measurements and analysis of a boreal forest fire, integrating the effects of greenhouse gases, aerosols, black carbon deposition on snow and sea ice, and postfire changes in surface albedo. The net effect of all agents was to increase radiative forcing during the first year (34 +/- 31 Watts per square meter of burned area), but to decrease radiative forcing when averaged over an 80-year fire cycle (-2.3 +/- 2.2 Watts per square meter) because multidecadal increases in surface albedo had a larger impact than fire-emitted greenhouse gases. This result implies that future increases in boreal fire may not accelerate climate warming.

Ecosystem↗
PubMed1997

An antigenically related polypeptide family is a major structural constituent of a stable acrosomal matrix assembly in bovine spermatozoa.

The apical and principal segments of the bovine acrosome contain a stable matrix complex that is bound to the outer acrosomal membrane and exhibits hydrolase-binding activity. The present study was undertaken to determine whether the outer acrosomal membrane-associated matrix complex (OMC) is composed of a unique set of acrosomal proteins and to define its fate during both capacitation and the acrosome reaction. A purified OMC fraction was isolated from ejaculated spermatozoa, and one polypeptide of 32 kDa (OMC32) was purified to homogeneity and used for N-terminal sequence analysis and preparation of monospecific antisera. Immunofluorescence staining of sperm with anti-OMC32 demonstrated that the polypeptide localized specifically to the apical and principal segments of the acrosome. Immunoelectron microscopy further revealed that OMC32 was restricted to the stable matrix assembly and was not associated with the inner acrosomal membrane or the equatorial segment. Immunoblot analyses of sperm lysates and of the purified OMC fraction revealed that anti-OMC32 recognized an antigenically related family of polypeptides between 38 and 19 kDa. These polypeptides exhibited no size processing during capacitation or the acrosome reaction, and they were not released during the acrosome reaction but remained in the particulate cell subfraction, associated with the hybrid membrane complex. N-terminal sequence analysis of OMC32 indicated a structural relationship to the SP-10 polypeptide family of human and baboon spermatozoa. The potential function of the OMC complex and differences in the intraacrosomal distribution of bovine OMC32-related polypeptides from that reported for acrosomal SP-10 polypeptides in other species are discussed.

Acrosome↗
PubMed1992

Evaluation of a rapid peptide-based anti-human immunodeficiency virus-1 antibody immunoassay.

A qualitative, visually interpreted, rapid, and synthetic peptide-based anti-human immunodeficiency virus-1 (HIV) antibody immunoassay has been developed that may be of value in situations in which rapid determination of HIV-1 status is important. Because questions have been raised about the accuracy of rapid anti-HIV-1 assays, the sensitivity, specificity, interobserver and intraobserver variability of the Genie HIV-1 assay (Genetics Systems, Seattle, WA) were determined. Sera from 56 patients with HIV-1 infections documented by enzyme immunoassay and western blot tested positive by this assay. Enzyme immunoassay- and western blot-negative sera from 30 visceral organ transplant donors were negative using the Genie assay. Specificity was examined further by testing sera from 29 patients hospitalized with a variety of medical disorders, including acute bacterial pneumonia, acute myocardial infarction, monoclonal gammopathy, and high titer antinuclear or antimitochondrial antibodies. Two of these patients were reactive with the enzyme immunoassay, both of which tested negative by western blot. All 29 tested negative using the Genie assay. In addition, sera from five patients with repeatedly reactive enzyme immunoassays and negative western blots tested negative by the Genie system. There was 100% agreement in interobserver and intraobserver studies. With the western blot as the reference method, the Genie assay exhibited 100% sensitivity and specificity and there was no observer variability.

AIDS Serodiagnosis↗
PubMed1991

Diagnostic significance of hypocomplementemia.

Hypocomplementemia is an important marker for the presence of IC-mediated disease and can be used to assess disease activity. However, in interpreting the clinical significance of hypocomplementemia, the following must be kept in mind: 1) There are numerous non-immunologic conditions that also can cause hypocomplementemia. Furthermore, some of these conditions can cause a multisystem disease that, along with the hypocomplementemia, can closely resemble an IC-mediated systemic vasculitis. Furthermore, these nonimmunologic conditions that lower serum complement levels can complicate the course of patients with inactive IC-mediated disease, spuriously indicating that the disease is active. The most relevant of these differential diagnostic problems are listed in Table 2. 2) There are a few conditions (for example, pregnancy) that can raise serum complement levels, thereby possibly obscuring the presence of a disorder (such as, active SLE) that is lowering complement levels. 3) There are some conditions that might be expected to lower serum complement levels, because of their effect on protein metabolism, but do not. Nephrotic syndrome, and moderately poor nutrition are examples. All of these factors should be considered when interpreting results of serum complement levels in a given patient.

Complement System Proteins↗
PubMed1990

Sensitivity and interobserver variability of the Recombigen-HIV-1 LA test.

The Recombigen-HIV-1 LA Test (Cambridge BioScience Corporation, Worcester, MA) uses recombinant peptides derived from the env gene product in a latex agglutination assay for the detection of antibodies to human immunodeficiency virus type 1 (HIV-1) and was recently approved by the Food and Drug Administration for marketing in the United States. It is intended for use as a screening test in physicians' offices, emergency rooms, and other settings where enzyme immunoassays are not practical or available. Concern has been raised over the sensitivity, specificity, and difficulty in interpretation of the agglutination pattern. The authors report on the sensitivity and interobserver variability of the assay as performed in a blinded fashion in a hospital laboratory by technologists experienced with other latex agglutination assays. In the first study, sera from 50 patients positive by enzyme immunoassay (EIA) (Abbott HIV EIA) and western blot (WB), performed with EPITOPE HIV western blot strips were assayed by one technologist using the latex agglutination technique. Forty-six samples were positive and four were negative, yielding a sensitivity of 92%. In the second study, 30 samples consisting of 10 negative by EIA and WB, 10 borderline by EIA and/or indeterminate by WB, and 10 positive by EIA and WB were evaluated by three technologists with the latex agglutination technique. There was agreement among all three technologists in 24 of 30 samples (80%). There was disagreement over one sample from the negative group (one technologist obtained a single false positive result), three from the borderline/indeterminate group, and two from the positive group (three technologists obtained false negative results on two samples). In summary, the authors report interobserver variation in interpreting 20% of tests, reflecting difficulty in assessing weak agglutination. Sensitivity of 92% is below that achievable with the EIA or WB techniques and limits the usefulness of the latex agglutination assay as a screening test.

AIDS Serodiagnosis↗
PubMed1990

Immunosuppressive effects of pentostatin.

The immune function of patients with hairy cell leukemia (HCL) and solid tumors was evaluated before and after treatment with the investigational drug 2'-deoxycoformycin (pentostatin; dCF). Thirteen HCL patients received doses of dCF of 2 to 4 mg/m2 intravenously at 2- to 6-week intervals for up to 15 courses. After completion of treatment, 12 of 13 patients had resolution of severe monocytopenia and five of nine had normal monocyte antibody dependent cellular cytotoxicity. There was statistically significant depression of total lymphocytes, T cells, and B cells. Evaluation of T subsets showed a decrease in CD4+ cells. Immunoglobulin G (IgG) in sera were decreased from baseline, while IgM and IgA were unaffected. There was no significant effect on skin-test reactivity or large granular lymphocyte numbers. Lymphoblastic transformation was variably affected. Natural-killer (NK) cell function was improved or unchanged after dCF treatment. Reevaluation of seven patients at 21 to 119 weeks after receiving dCF demonstrated that recovery to normal T- and B-cell numbers and subsets does occur. Five solid tumor patients were given dCF at 4 mg/m2 intravenously at 1- to 2-week intervals for up to five courses. There was significant reduction in T cells, B cells, CD4+, and CD8+ cells with no statistically significant effect on the other immune parameters. We conclude that low doses of dCF can cause persistent immunosuppression though recovery may occur after the drug is stopped. In patients followed after completion of dCF, there was no associated increase in second malignancies or unusual infections.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1989

Relative value of prostate-specific antigen and prostatic acid phosphatase in diagnosis and management of adenocarcinoma of prostate. Ohio State University experience.

Serum concentrations of prostate-specific antigen (PSA), prostate-specific acid phosphatase (PAP), and transrectal prostatic ultrasound were utilized in the evaluation of 193 men with various urologic disorders. Of the 193 patients, 48 had prostate cancer, and the other 145 included 5 with genitourinary neoplasms, 69 with benign prostatic hypertrophy, and 71 with other non-neoplastic genitourinary disease. PSA levels were elevated in 35 patients with prostate cancer and in 25 of the 145 without prostate cancer. PAP levels were elevated in 15 with prostate cancer and in 2 of the 145 without prostate cancer. The data indicate that PSA is a more sensitive but less specific tumor marker than PAP in the detection of prostate cancer. PSA appears to be more sensitive than PAP in monitoring the response to treatment. The use of PSA and PAP jointly to detect and to monitor prostate cancer did not appear to enhance the clinical utility over that of PSA alone.

Acid Phosphatase↗
PubMed1989

Infectious hazards in the clinical laboratory: a program to protect laboratory personnel.

The increasing risk of exposure to blood-borne pathogens in the health care setting makes the development of effective infection control programs in the laboratory workplace critical. Central to such programs is the concept of universal precautions. The program described here relates the level of protection or precaution to the potential danger for infection, given the laboratory workstation and task which is to be performed. Four Levels of Protection are described. Implementation of this program requires that each workstation and procedure in each laboratory section be reviewed by the laboratory director and supervisory personnel for risk of exposure. Implementation additionally requires that provisions be made for both the initial and continuing education of laboratory employees. Laboratory directors and supervisors should also monitor the program to ensure compliance. There will certainly be situations unique to individual institutions or laboratory settings that may require precautions or policies over and above those described by universal precautions. Laboratory policies will not gain acceptance if they are developed and implemented without the advice and cooperation of the hospital medical staff. Employee acceptance of infection control policies will be greater if actual development and implementation actively involves the laboratory personnel who will practice them. The program described here is but one approach to the problem. Employers and laboratory directors must understand that it is their responsibility to develop a program that provides appropriate safeguards for workers who may be exposed to infectious agents in the laboratory workplace and to ensure that employees are properly trained and educated in the proper use and application of those safeguards.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Bullous lichen planus: diagnosis by indirect immunofluorescence and treatment with dapsone.

Bullous lichen planus may be confused with other subepidermal bullous dermatoses, especially if bullae arise on normal-appearing skin. We present two patients who were originally thought, on the basis of clinical and histopathologic criteria, to have bullous pemphigoid. However, results of standard indirect and direct immunofluorescence assays did not support the diagnosis of bullous pemphigoid. Further investigation using the indirect autologous immunofluorescence assay revealed deposits of immunoglobulins in the stratum granulosum. Moreover, the indirect allogeneic immunofluorescence assay (using papular lichen planus lesional substrates from different patients) was positive for the same pattern, confirming the diagnosis of bullous lichen planus. Bullous lichen planus with bullous pemphigoid-like histologic features can be differentiated from bullous pemphigoid on the basis of the indirect autologous and allogeneic immunofluorescence assays for circulating antigranulosum antibodies. Both patients were treated with systemic corticosteroids. One patient went into remission with this therapy alone; the other patient had a favorable response when dapsone was given with systemic corticosteroids. The suggestion that there is a subset of bullous lichen planus with bullous pemphigoid-like histologic features that responds to dapsone needs to be explored.

Adult↗
PubMed1986

Gastrointestinal malformations associated with prune belly syndrome: three cases and a review of the literature.

Prune belly syndrome (PBS), a triad consisting of abdominal musculature hypoplasia, urinary tract malformations, and cryptorchidism, is frequently associated with other congenital malformations. Although it is acknowledged that gastrointestinal (GI) malrotation and mesenteric anomalies are frequent in PBS, other GI anomalies are generally considered to be exceedingly rare. Here we describe 3 autopsy cases with severe malformations of both midgut and hindgut derivatives and review the world literature to evaluate the spectrum of GI malformations associated with this syndrome. The relatively high frequency of distal stenoses and atresias suggests that the anomalous mesenteric attachments may predispose to prenatal volvulus and subsequent anatomic bowel obstruction. Postnatal volvulus is also occasionally observed. Infants with PBS also appear to be at a higher risk for persistence of the common fetal cloaca.

Adult↗