Criteria for evaluating the clinical and practical utility of models used by nurses

Arguably, nursing, like all health care disciplines, is an applied science. Essentially, this refers to the application of theory in order to understand and respond to the health problems of clients. These theories may be drawn (borrowed) from any applied science, or generated inductively from clinical nursing practice. Alternatively, nurses may attempt to apply deductive theory (global theoretical frameworks) known as nursing models. In this paper, all theoretical approaches, irrespective of origin, are referred to as models used by nurses. Thirteen criteria by which clinicians, and others, can evaluate the clinical and practical utility of models used by nurses which are expressed in the form of questions are identified and discussed. The criteria are an extension, both in detail and in number, of those developed by Reynolds and Cormack and subsequently applied by those writers to the Johnson Behavioural System Model of Nursing. The value, or otherwise, of individual models, or of models in general, will not be discussed in this paper. However, the authors propose that if the evaluation criteria described here are applied to existing models, serious deficits will be identified in relation to their clinical and practical utility.     

Toxic cardiogenic shock in a patient receiving weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin

A 54-year-old man was treated with weekly 24-h infusion of high-dose 5-fluorouracil (2600 mg/m2) and leucovorin (100 mg/m2) for metastatic colon cancer. At first, he tolerated the treatment well and no significant toxicity was identified. After a total of eight courses of treatment, a stable disease was observed, but mild shortness of breath was found on occasion. The patient had no previous history of cardiac disease and the heart performance assessed by left ventricular ejection fraction before treatment was normal. Unfortunately, acute pulmonary edema with lethal cardiogenic shock occurred during the ninth course of treatment, in spite of intensive medical treatment. The chest X-ray showed extreme cardiomegaly. Repeated assessment of his heart function by echocardiogram and ventricular ejection fraction revealed a very poor cardiac performance. Toxic cardiogenic shock during weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin is extremely rare. To the best of our knowledge, no case has been reported in the English literature. We report a case and the relevant literature about the incidence, clinical picture and possible pathophysiology on 5-fluorouracil-related cardioxicity is reviewed.      

The relationship between CR3 deficiency and neutrophil actin assembly

Polymorphonuclear leukocytes (PMN) with a deficiency of the complement receptor type 3 (CR3) membrane glycoprotein family have impairments in the ability to adhere to surfaces as well as chemotactic and phagocytic defects, processes that require a functional contractile apparatus. PMN from the patient with neutrophil actin dysfunction (NAD) displayed similar functional characteristics to those with CR3 deficiency suggesting the two disorders may be the same disease. In order to evaluate the relationship between CR3 deficiency and actin assembly, actin filament assembly was measured in PMN from six previously reported homozygotes (two severe and four moderate CR3-deficient patients) as well as five heterozygotes for CR3 deficiency. PMN from all patients had normal unstimulated concentrations of F-actin and after exposure to the chemotactic peptide FMLP (5 x 10(-7) mol/L for 5 to 40 seconds at 25 degrees C) assembled actin normally. Pretreatment of normal PMN with concentrations of monoclonal anti-alpha CR3 antibody, capable of blocking PMN adherence, also failed to impair FMLP- induced actin filament assembly. CR3 glycoprotein expression was measured in PMNs from the mother, father, and older sister of the NAD patient (N Engl J Med 291:1093, 1974). Actin filament assembly was recently shown to be defective in PMNs from all three family members. The total concentrations of the alpha and beta CR3 subunits were below normal in PMN detergent extracts from the mother (25% of simultaneous controls) and older sister (56% of control). PMN surface expression of these two subunits was also found to be depressed (mother, 50%; older sister, 63% of control). These findings suggest these two NAD family members are heterozygote carriers for CR3 deficiency as well as NAD. Simultaneous studies of the father, however, demonstrated normal total concentrations of both the alpha and beta CR3 subunits (126% of controls) as well as normal surface expression of both subunits after phorbol myristate acetate stimulation and incubation at 37 degrees C (mean, 112% of controls) but slightly lower than normal levels after FMLP stimulation (mean, 83%). These findings indicate that CR3 deficiency generally is not associated with defective actin filament assembly and support the conclusion that NAD represents a unique kindred in which PMN actin function differs from previously reported genotypes of CR3 deficiency.     

Primary low-grade B-cell lymphoma of the urinary bladder: case report and literature review

The first recorded case of lymphoma of the bladder was reported by Eve and Chaffey in 1885. Malignant lymphoma of the bladder can be classified into one of three different clinical groups: 1) Primary lymphoma localized to the bladder; 2) Lymphoma presenting in the bladder as the first sign of disseminated disease (non-localized lymphoma); 3) Recurrent bladder involvement by lymphoma in patients with a history of malignant lymphoma (secondary lymphoma). Primary extranodal marginal zone lymphoma of mucosa associated lymphoid tissue (MALT type) of the urinary bladder, first described by Kempton et al in 1990, is the most common primary bladder lymphoma and associated with an excellent prognosis. We present a patient with gross hematuria who was found to have a primary bladder lymphoma and review the relevant literature.     

Amidolytic assay of human factor XI in plasma: comparison with a coagulant assay and a new rapid radioimmunoassay

The traditional coagulant assay for plasma factor XI suffers from a relatively high coefficient of variation, the need for rare congenitally deficient plasma, and a poor correlation between precision and sensitivity. We have developed a simple functional amidolytic assay for factor XI in plasma using the chromogenic substrate PyrGlu-Pro-Arg- p-nitroanilide (S-2366). After inactivation of alpha 1-antitrypsin, CI inhibitor, and other plasma protease inhibitors with CHCI3, plasma was incubated with kaolin, in the absence of added calcium, which limited the enzymes formed to those dependent on contact activation. Soybean trypsin inhibitor was used to minimize the action of kallikrein on the substrate. Once the reaction was complete, corn trypsin inhibitor was used to inactive factor XIIa, the enzyme generated by exposure of plasma to negatively charged surfaces, which had activated the factor XI. The assay is highly specific for factor XI, since plasma totally deficient in that zymogen yielded only 1%-3% of the enzymatic activity in normal plasma under identical conditions. The requirements for complete conversion of factor XI to XIa in plasma within 60 min were, respectively, factor XII, 0.6 U/ml, and high molecular weight kininogen, 0.2 U/ml. Prekallikrein was not an absolute requirement for complete activation but did accelerate the reaction. The intraassay coefficient of variation was 3.4%, and the mean of 35 normal plasmas was 1.00 U +/- 0.24 SD. In addition, a new rapid radioimmunoassay was devised using staphylococcal protein A as the precipitating agent for a complex of factor XI antigen with monospecific rabbit antibody. The mean was 1.01 U +/- 0.30 SD. The correlation coefficients for amidolytic versus coagulant and amidolytic versus radioimmunoassay were r = 0.95 for the former and 0.96 for the latter. Thus, a simple, accurate amidolytic assay and a radioimmunoassay have been devised for measuring factor XI in plasma that correlate well with the coagulant activity of factor XI, as determined in our laboratory.     

Moderate acute exercise (70% VO2 peak) induces TGF‐β, α‐amylase and IgA in saliva during recovery

Strenuous exercise promotes changes in salivary IgA and can be associated with a high incidence of upper respiratory tract Infections. However, moderate exercise enhances immune function. The effect of exercise on salivary IgA has been well studied, but its effect on other immunological parameters is poorly studied. Thus, this study determined the effect of moderate acute exercise on immunological salivary parameters, such as the levels of cytokines (TGF‐β and IL‐5), IgA, α‐amylase and total protein, over 24 h. Ten male adult subjects exercised for 60 min at an intensity of 70% VO₂ peak. Saliva samples were collected before (‘basal’) and 0, 12 and 24 h after an exercise session. The total salivary protein was lower after 12 and 24 h than immediately after exercise, whereas α‐amylase increased at 12 and 24 h after exercise compared with basal levels. The IgA concentration was increased at 24 h after exercise relative to immediately after exercise, and there was no difference in the IL‐5 while TGF‐β concentration increased in recovery. In conclusion, 70% VO₂ peak exercise does not induce changes immediately after exercise, but after 24 h, it produces an increase in salivary TGF‐β without changing IL‐5.     

Endovascular treatment of a Superior Mesenteric Artery Syndrome variant secondary to traumatic pseudoaneurysm

Pseudoaneurysms related to the superior mesenteric artery (SMA) are a recognised complication of trauma to the vessel, and successful treatment with stenting has been previously described. We report the case of a patient who presented with obstruction of the fourth part of the duodenum secondary to a traumatic pseudoaneurysm, a hitherto unreported variant of superior mesenteric artery syndrome. Exclusion of the pseudoaneurysm and relief of the duodenal obstruction were simultaneously achieved by placement of a covered stent.     

Factors predictive of response and survival in patients with metastatic colorectal cancer in Taiwan

5-Fluorouracil in combination with leucovorin has been shown to be active in therapeutic trials of metastatic colorectal carcinoma. In this study, we administered these drugs to 72 patients with metastatic colorectal carcinoma. Thirty-six of them without previous exposure to 5-fluorouracil were treated with weekly bolus injections of 5-fluorouracil (425 mg/m2) and leucovorin (25 mg/m2) supplemented with oral levamisole. Another 36 patients with or without prior 5-fluorouracil treatment received 5-fluorouracil 3,000 mg/m2 and leucovorin 300 mg/m2 in a 48-hour continuous infusion every two weeks. Clinical efficacy and toxicity were assessed by WHO criteria. Variables were tested for relations to response and survival by univariate and multivariate analysis. The response rate was 19.4% in weekly bolus arm and 13.9% in biweekly high-dose infusion arm (P = 0.527). Median survivals in the two arms were 18.4 months (weekly) and 21 months (biweekly) respectively (P = 0.708). Gastrointestinal side effects including nausea, vomiting, diarrhea and mucositia were the major toxicities of these regimens. By multivariate analysis, the only factor to influence response rate was the site of metastases (P = 0.009). The only factor to affect survival was performance status of the patient (P = 0.0001). We concluded that the two 5-fluorouracil based regimens are well-tolerated and shown to have a response rate comparable with previous reports of similar regimens in patients with metastatic colorectal cancer. Only liver metastases seemed to have a better response to therapy. Performance status is the most important prognostic factor in patients with metastatic colorectal cancer.