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Biomedical subjects

J M Carr

Publications and source records attributed to J M Carr.

32 records · Page 2Linked to original sources

Babesiosis. Diagnostic pitfalls.

A case of babesiosis complicated by quinine-induced hemolysis is described. A splenectomized woman contracted babesiosis after visiting an endemic area. The patient presented with high fevers and minimal hemolysis. While she was on treatment, the hemolysis increased. The increased hemolysis was initially attributed to babesiosis, but after additional evaluation quinine therapy was found to be the cause. In the setting of this brisk hemolysis, there was an increase in red blood cell inclusions. At first, the inclusions were thought to be Babesia, but iron stain demonstrated that many of the inclusions were hemolysis-induced Pappenheimer bodies. The role of the clinical laboratory in sorting out this confusing picture is presented.

Adult↗

Alteration of aliphatic lipid proton NMR linewidths by malignant tumors in guinea pigs.

Water-suppressed proton nuclear magnetic resonance spectroscopy was used to observe plasma lipoprotein lipid methyl and methylene resonances from guinea pigs which had been injected with viable or heat-killed line 1 or line 10 tumor cells or sterile oil. It was shown that the widths of these resonances became significantly sharper as the number of tumor cells grew. Plasma from tumor-free control animals showed no change in the NMR linewidths. It is concluded that the changes observed reflect a specific host response to viable tumor cells, and in these models there is a reciprocal relationship between the number of viable tumor cells and the linewidths of plasma lipoprotein methyl and methylene resonances.

Animals↗

Diagnosis of disseminated intravascular coagulation. Role of D-dimer.

Detection of the cross-linked fibrin degradation fragment, D-dimer, in patients at risk for disseminated intravascular coagulation (DIC) is strong evidence for the diagnosis. D-dimer confirms that both thrombin generation and plasmin generation have occurred. Patients at risk for DIC (58) and normal controls (7) were studied. Thirty-three patients had DIC--with fragment D-dimer identified in their serum by immunoblotting. Latex agglutination measurements of fibrin(ogen) degradation products (FDPs) and D-dimer were compared with immunoblotting in the detection of D-dimer. FDP measurement was extremely sensitive but not specific. D-dimer measurement was less sensitive but highly specific. Used in tandem, screening with FDP and confirming with D-dimer, sensitivity and specificity were maximized, rendering a predictive value of a confirmed FDP of 100% in this cohort. D-dimer is a valuable adjunct for the laboratory diagnosis of DIC but is most appropriately used as a confirmatory test for the very sensitive FDP test.

Adult↗

Detection of malignant tumors. Water-suppressed proton nuclear magnetic resonance spectroscopy of plasma.

A sensitive and specific blood test for cancer has long been sought. The water-suppressed proton nuclear magnetic resonance (NMR) spectrum of plasma is dominated by the resonances of plasma lipoprotein lipids. We measured the mean line widths of the methyl and methylene resonances, which were found to be correlated with the presence or absence of malignant tumors. Values for the average line width were lower in patients with cancer. We analyzed plasma from 331 people (normal controls, patients with malignant and benign tumors, patients without tumors, and pregnant patients); NMR analysis and measurement of line widths were blinded to diagnosis or patient group. The mean line width for 44 normal controls (+/- SD) was 39.5 +/- 1.6 Hz. For 81 patients with untreated cancer, demonstrated by biopsy, the line width was 29.9 +/- 2.5 Hz. Patients with malignant tumors were reliably distinguished from normal controls by this method (P less than 0.0001), and differed from patients with diseases that did not involve tumors (line width, 36.1 +/- 2.6 Hz; P less than 0.0001). Patients with benign tumors (e.g., those of the breast, ovary, uterus, and colon) had line widths of 36.7 +/- 2.0 Hz and were different from those with malignant tumors (P less than 0.0001). However, pregnant patients and those with benign prostatic hyperplasia had line widths consistent with the presence of malignant tumors. The narrowing of lipoprotein-lipid resonances with cancer is consistent with the response of a host to tumor growth. We conclude that these preliminary results demonstrate that water-suppressed proton NMR spectroscopy is a potentially valuable approach to the detection of cancer and the monitoring of therapy.

Adolescent↗

Efficacy of platelet transfusions in immune thrombocytopenia.

Records of 11 patients with immune thrombocytopenia (idiopathic and quinidine-induced) were evaluated retrospectively for response to platelet transfusion. Good post-transfusion platelet count increments occurred on one or more occasions in seven of the 11 patients, with 13 of 31 platelet transfusions (42 percent) resulting in immediate post-transfusion increments of 20,000/mm3 or more. Next-day platelet counts remained elevated in association with five of these 13 transfusions. This study demonstrates that, contrary to common opinion, platelet transfusions can raise the platelet count in many patients with immune thrombocytopenia, and therefore may be beneficial in actively bleeding or high-risk patients with this disorder.

Adult↗

Analysis of elevated fibrin(ogen) degradation product levels in patients with liver disease.

Plasma and serum from patients with liver disease and elevated fibrin(ogen) degradation product (FDP) levels as measured by latex agglutination were analyzed by immunoblotting to characterize the FDP in these patients. An antihuman fibrinogen antibody was used that recognizes fibrinogen, fibrin monomer, soluble high molecular weight fibrinogen and fibrin polymers, as well as high molecular weight cross-linked degradation fragments, and the smaller fragments X, Y, D-dimer, D, and E. The analytic procedures were validated with plasma and serum from patients known to have intravascular fibrinolysis associated either with disseminated intravascular coagulation (DIC) or with thrombolytic therapy. The samples demonstrated a spectrum of plasmin degradation fragments on the immunoblots. Twenty-eight of 35 patients with liver disease (80%) had no evidence of plasmin degradation fragments in their plasma or serum. The cause of the elevated FDP levels as measured by latex agglutination was thought to be fibrin monomer or unclottable fibrinogen that was retained in the sera of some of these patients. Seven patients (20%) were found to have circulating plasmin degradation fragments. In addition to liver disease, however, these patients all had an illness (sepsis, shock, and pancreatic carcinoma) independently associated with intravascular coagulation and fibrinolysis. Three patients who lacked plasmin fragments also had pancreatic carcinoma or sepsis. The two groups of liver disease patients could not be clearly differentiated on the basis of clinical or laboratory evidence, but the blotting procedure proved to be a useful discriminator.

Agglutination↗

Circulating membrane vesicles in leukemic blood.

Ultramicroscopic membrane vesicles were found in the plasma of 17 patients with certain types of leukemia (acute promyelocytic leukemia, acute monocytic leukemia, acute myelomonocytic leukemia, and chronic myelogenous leukemia) and in guinea pigs with the L2C leukemia. Labeled vesicles were cleared from normal guinea pig plasma according to a two exponential function with a half-life for the second exponent of greater than 11 h. By immunofluorescence, vesicles shared antigens with the L2C leukemic cells. Attempts to elucidate the cellular origin of the circulating vesicles in human leukemias were less definitive. However, vesicles did not react with the platelet membrane antigen GP IIb/IIIa nor did the presence of circulating vesicles or vesicle-associated procoagulant activity correlate with the platelet count. In three patients studied serially, circulating vesicles paralleled disease activity. Vesicles were not detected in 16 other patients with leukemias including acute myelogenous leukemia and most lymphoid leukemias. Similarly, vesicles were not present in 29 normal plasmas or in 10 plasmas from patients with solid tumors or nonmalignant hematological disorders. In contrast to vesicles of similar appearance shed by a variety of solid and ascites tumor cells in vitro and in vivo, the vesicles circulating in leukemia patients and guinea pigs expressed variable and generally weak procoagulant activity and no tissue factor activity. Thus, although many of the patients with circulating vesicles expressed abnormal coagulation, we were not able to establish a close pathogenetic relationship between the procoagulant activity of circulating vesicles and clinical coagulopathies.

Animals↗

Soft tissue attenuation of acoustic emission pulses.

The soft tissue attenuation of acoustic emission signals was measured by transmitting pulses through volunteers and measuring the decay of the waveform characteristics of the pulse as a function of the thickness of the interposed tissue. Waveform characteristics of the received signal (signal duration, number of counts, peak amplitude, energy, and rise time) demonstrated an exponential decrease with increasing tissue thickness. The decrease appeared insensitive to the frequency of the pulse within the range of 50 to 600 KHz.

Acoustics↗

Clonal distribution of resistance plasmid-carrying Salmonella typhimurium, mainly in the Middle East.

Strains of Salmonella typhimurium of predominantly Middle Eastern origin, but distributed from England to India, were found to carry at least three types of resistance plasmid. The most important was initially identified as an F(I) plasmid by compatibility tests, but differs from the F factor on the one hand and the F(I) factors R162 and ColV on the other. The three groups of F(I) plasmids can be distinguished by their compatibility reactions with the MP10 plasmid of S. typhimurium (Smith, Humphreys, Grindley, Grindley & Anderson, 1973) and group H(1) factors: the F factor is unilaterally incompatible with group H(1) (Smith, Grindley, Humphreys & Anderson, 1973; Anderson, 1975b); the F(I) factors are compatible with MP10 and group H(1); and F(I)me factors are incompatible with MP10 but compatible with H(1). The majority of S. typhimurium cultures belonged to phage type 208; most of those that did not, belonged to types related to 208. Only a minority of their F(I)me plasmids were autotransferring. The remainder were mobilizable by F-like plasmids, and by group H(1) and H(2) factors, but not by the fi(-) I(1) factor Delta, or by plasmids of the I(2), B, P, W, N and com 7 groups. The compatibility reactions of the autotransferring F(I)me plasmids were identical with those of the non-transferring members of the group, and both were large, single-copy plasmids.The S. typhimurium strains of this series carried A or AK, and SSu resistance determinants: small, probably multicopy, non-transferring plasmids similar to those originally described in phage type 29 of S. typhimurium (Anderson & Lewis, 1965b).These S. typhimurium cultures probably represent a clone of wide geographical distribution. The accurate epidemiological study of such clonal outbreaks requires, in addition to phage typing, precise identification of the plasmids harboured by the epidemic strains, and may have to be carried to the molecular level.F(I)me plasmids were identified in other drug-resistant salmonellas, notably in a strain of S. wien which caused large outbreaks of mainly paediatric infection in Algeria, and also spread to Britain. An F(I)me plasmid was found in S. typhi phage type 44 from Algeria, in which the phage-restricting properties of the plasmid are responsible for the specificity of the type.

Ampicillin↗

Bacteriophage restriction in Salmonella typhimurium by R factors and transfer factors.

A total of 2716 R factors and transfer factors isolated from Escherichia coli and salmonellas of human and animal origin were studied for their phage-restrictive effects in Salmonella typhimurium phage type 36. All of 1402 wild fi(+) factors were non-restricting. The F factor of E. coli K12 was unique among the F-like factors tested in that it inhibited lysis of type 36 by one typing phage. In contrast, eleven distinct changes in the phage type of 36 were produced by fi(-) I-like factors. I-like plasmids can thus be subdivided by this method.I-like R factors and transfer factors from human and animal enterobacteria were categorized by their phage-restrictive effects in type 36. Factors resembling Delta in this respect predominated among fi(-) I-like factor from human E. coli and S. typhimurium and from porcine E. coli. Delta-like and ColI-like fi(-) factors were equally distributed in bovine S. typhimurium. ColI-like factors were commonest in bovine and avian E. coli.

Animals↗

Integrating patterns of knowing in an undergraduate nursing course.

A complex and changing contemporary healthcare system and holistic consideration of patients create a need for nurses who have a sophisticated, broad knowledge base. Empirical, ethical, personal, and aesthetic patterns of knowing provide a meaningful background for course development and offer students the opportunity to understand themselves and their patients through multiple modes of awareness. In this article, the author describes the integration of patterns of knowing into an undergraduate nursing course. Course objectives, content, assignments, and evaluation are discussed. A course such as this one that incorporates scientific knowledge of humans in health and illness, aesthetic perception of human experiences, personal understanding of self and others, and the capacity to make ethical choices enriches student learning about the art and science of nursing.

Curriculum↗

A feasibility study for removing tissue contamination from porous implants.

Porous implants that are unpackaged in the operating room but not implanted are discarded because they must be considered potentially contaminated with tissue. To reduce this waste, a method was developed to decontaminate these implants so that they can be resterilized and implanted. This method consists of ultrasonic scrubbing, sequentially, in aqueous solutions of dishwashing detergent, 7% nitric acid, and 5.25% sodium hypochlorite. The effectiveness of the method was tested by contaminating samples of porous implants with tissue, subjecting them to the decontamination method, and then using the following techniques to determine whether any tissue remained. The weights of samples after decontamination were compared with their weights before contamination. The rate of removal of labeled protein contamination from samples was measured. The capacity of decontaminated samples to activate immune system cells was assayed. Bioburden evaluations were performed on decontaminated samples. Within the measurement capabilities of each technique, no tissue was detected in any sample after decontamination.

Animals↗