Biomedical subjects
Publications and source records attributed to B Bennett.
The incidence of adenocarcinoma of the colon in patients with gastric non-Hodgkin's lymphoma (NHL) was much higher than that in patients with other forms of NHL. Abdominal symptoms in patients with previously treated gastric NHL should be investigated and treated carefully with this association in mind.
Nodose (inferior vagal sensory) ganglia were removed from neonatal rats, enzymatically dispersed using neutral protease, and maintained on previously dispersed rat atriacytes. After 7-10 days in culture, calcitonin gene-related peptide (CGRP) was present in 1-3 times the molar amount of substance P (SP). The content of SP was doubled by the addition of nerve growth factor (NGF) whereas CGRP was significantly less increased by 50% or less. The addition of forskolin increased SP and CGRP levels in cultures with or without NGF by 60-80 percent. Phorbol ester (PMA) did not alter SP content but significantly raised CGRP content by 40% in NGF supplemented cultures (P less than 0.001). Corticosterone, 0.01-0.1 microM, reduced SP content by 30% independently of NGF but had no effect on CGRP. These studies demonstrate that SP in vagal sensory neurons is more sensitive than CGRP to the effects of NGF or corticosterone. Both peptides are up-regulated by presumed increases in intracellular cyclic AMP, while CGRP (or CGRP neurons) may be independently regulated by protein kinase C.
The MMPI was administered twice to 40 graduate students to determine the utility of the Weiner subtle and obvious scales (D, HY, PD, PA, MA) for estimating how fake good and fake bad response sets might influence full scale scores. The first time, the MMPI was administered under standard conditions. Subjects then were divided randomly into two groups: fake good (complete MMPI for job application) and fake bad (qualify for psychotherapy). There were significant multivariate test effects (standard vs. response set) for the raw scores of all five obvious, subtle, and full scales. However, when raw scores were converted to T scores to ascertain practical significance, the obvious scales appeared to provide the most useful information to enhance the interpretation of full scale scores in normal populations.
Numerous investigators have demonstrated that derangements in serum transferrin and iron can contribute to susceptibility to infection, but the complexity and imprecision of assays have impeded both research and development of clinical testing in this area. This article describes an automated assay for measuring the microbial inhibitory activity of transferrin in serum and its use in patients with acute myelogenous leukemia (AML) and in normal controls. The assay measured the ability of heat-inactivated serum to inhibit the growth of an antibiotic-resistant strain of Pseudomonas aeruginosa. The serum dilutions were prepared in a special low iron chemically defined broth. An inhibition index, the reciprocal of the serum dilution producing 50% inhibition of bacterial growth when compared with the growth in broth alone, was determined. The results showed the serum from the patients with leukemia had a significantly lower inhibition index than that of controls (16 +/- 11 vs. 35 +/- 13, P less than 0.01). In addition, they had higher serum iron levels (162 +/- 65 vs. 75 +/- 27, P less than 0.01), lower serum transferrin levels (231 +/- 65 vs. 309 +/- 71, P less than 0.01), and higher percentage saturation of transferrin with iron (59 +/- 21 vs. 20 +/- 8, P less than 0.01) than did controls. Because the assay uses equipment available in many clinical laboratories, it could be developed for routine use as an index of susceptibility to infection in selected patients.
Three consecutive patients with acute promyelocytic leukaemia who presented with severe haemorrhagic syndromes were studied and the findings contrasted with those of two patients with classical defibrination after electroshock or complicated labour. The leukaemic patients showed no depletion of fibrinogen. There was no evidence of disordered thrombin generation by either intrinsic or extrinsic pathway sufficient to account for their haemorrhage. All, however, showed strikingly enhanced fibrinolytic activity, which could have accounted for bleeding. This fibrinolytic disorder was characterized by free u-PA in the plasma and differed from that seen after classical defibrination, where free t-PA was observed. U-PA was found also in malignant promyelocytes, which may be the source of u-PA activity in the patients' plasma. Bleeding in promyelocytic leukaemia may be primarily a fibrinolytic disorder.
Civilian helicopters and emergency medical services in the United States have been in existence for approximately 15 years. The rapid growth of this type of health care delivery coupled with an increasing number of accidents has prompted professional and lay scrutiny of these programs. Although they have a demonstrated history of benefit to patients, the type and severity of injuries to patients who are eligible for helicopter transportation need further definition. The composition of the medical crews and the benefits that particular crew members bring to the patients require ongoing evaluation. Significant questions regarding the number of pilots in a helicopter and in a program remain to be answered. This article reviews the role of emergency medical air transport services in providing care to trauma patients, staff training and evaluation, and safety criteria and offers recommendations to minimize risks to patients and crews.
Eighty-two patients, ranging in age from 11 months to 24 years, underwent the percutaneous placement of an implanted catheter in order to have improved venous access. Thirty-five patients (43%) were beginning chemotherapy for cancer, four (5%) had a chronic hematologic disorder, and the remaining 43 (52%) were on chemotherapy for cancer. The mean duration of catheter function was 168 days (range of 7-1,030 days), with a cumulative experience of 18,812 days of catheter use. Complications were minimal. Only four catheters (5%) required removal secondary to infection, infiltration, or tissue breakdown. Substantially reduced complication rates were observed as compared to other studies using implanted central venous catheters. Implanted central venous catheters were proven to be safe in patients with hematologic disorders. These catheters enhance the ability to infuse chemotherapy, hyperalimentation, blood products, anesthesia, and imaging solutions and are safe to use in patients with a hemostatic or host defense deficiency.
Forearms of rhesus monkeys were treated with [3H]avermectin B1a in three different vehicles and concentrations so that the penetration of avermectin B1a through skin could be determined. In order to simulate exposure of farm workers, such as mixer-loaders, applicators, and harvesters, to this pesticide, avermectin B1a was applied to the forearms of the monkeys as an emulsifiable concentrate (300 micrograms/monkey), a diluted emulsifiable concentrate (4.5 micrograms/monkey), and as a suspension in water (216 micrograms/monkey). After 1 or 10 hr of exposure, the treatment area was washed. The levels of radioactivity were determined in the urine, feces, plasma, and wash. On the basis of the amounts of radioactivity excreted in the urine and feces and the levels of radioactivity in the plasma after dermal application compared to those found after intravenous administration of the compound, less than 1% of the doses was absorbed. These data indicate that avermectin B1a would not readily penetrate the skin of farm workers exposed to it. Therefore, the hazard to farm workers exposed to this compound would be substantially mitigated.
During normal pregnancy maternal haemostasis alters to protect against bleeding with a rise in plasma clotting factor levels and increased inhibition of fibrinolysis. The latter is due in part to increased levels of the 48 kDa plasminogen activator inhibitor (PAI-1) present in the plasma of non-pregnant individuals. A second plasminogen activator inhibitor (PAI-2) occurs in placenta and in a cultured histiocytic lymphoma cell line. We report here the identification by SDS-PAGE and zymography of PAI-2 in plasma during normal pregnancy. PAI-2 was present in two molecular forms of about 75 and 130 kDa, which were detectable at 12 weeks gestation and which persisted in the maternal circulation for up to 7 days after delivery. These forms of PAI-2 appear to be distinct from purified PAI-2, which has a molecular mass of 47-60 kDa and which is not normally detectable in this zymographic system, since it is sensitive to denaturants. The novel forms of PAI-2 may represent complexes or aggregates that retain activity after SDS-PAGE.
Cytotoxic chemotherapeutic agents, particularly the anthracyclines, are known to be cardiotoxic, but toxic effects on the aorta have not previously been documented. In this study, diameters of ascending and descending thoracic aortae were measured by computerized tomography in 69 patients with lymphoma, before and after first-line treatment with one of 7 different regimes. Minor increases in aortic diameter over the study period due to the aging process were expected. These increases were greater than anticipated in both the ascending and the descending aortae after chemotherapy with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) and CVP (cyclophosphamide, vincristine, and prednisolone) regimes. Smaller changes, or changes which were not statistically significant, were noted after MVPP (mustine, vinblastine, procarbazine, and prednisolone), ChlVPP (chlorambucil, vinblastine, procarbazine, and prednisolone), ChlVP (chlorambucil, vincristine and prednisolone), mediastinal radiotherapy, and radiotherapy plus MVPP (MVPP/XRT). Cardiovascular damage associated with certain forms of cytotoxic therapy is not confined to the heart, but also affects the aorta.
Patients undergoing first-line chemotherapy after diagnosis of lymphoma have considerable DNA damage in their peripheral blood lymphocytes, using sister chromatid exchange (SCE) frequency as a sensitive indicator. Different drug regimens produce different patterns of changes in SCE frequency. These may be related to their potential to induce second malignancies.
Three patients with condylomata acuminata of the urinary bladder are reported. Two of the patients were immunosuppressed, and one had longstanding extensive condylomata acuminata of the external genitalia and adjacent areas. All lesions recurred at least once and were difficult to treat. The diagnosis was confirmed by in situ hybridization on archival material with human papillomavirus (HPV) DNA probes under stringent conditions. In two of the patients, probes for HPV types 6 and 11 were positive; HPV 11 only was identified in one patient. Probes for HPV types 16 and 18 and pBR322 vector controls were negative. In one patient with a strong hybridization signal, the lesion was also positive for common papillomavirus antigen. DNA content measured by cytophotometry of Feulgen-stained whole nuclei isolated from lesions in two patients revealed a markedly aneuploid DNA pattern. Whether this is a factor in the behavior of the lesions is not known at this time. Although rare, HPV infection of the urinary bladder may result in widespread condylomatosis and may mimic giant condylomas of Buschke-Löwenstein or even verrucous carcinomas, sometimes necessitating radical treatment. Nevertheless, until there is proof to the contrary, the lesions must be considered benign and should not be confused with squamous cancer of the bladder.
The distribution of PAI-1 in the plasma and platelets of normal individuals and of patients with platelet abnormalities was studied. An ELISA, capable of measuring PAI-1 in plasma at 1.5 ng/ml, and a functional assay of t-PA inhibition were used to assay platelet-free plasma (PFP), platelet-rich plasma in which the platelets were lysed (PRP) and serum. The PAI-1 concentration of normal PFP was 21.0 +/- 7.2 ng/ml (mean +/- SD) and those of PRP and serum were 282.6 +/- 68.0 and 270.3 +/- 71.9 ng/ml. The concentration of PAI-1 in PRP was proportional to the platelet count with 0.67 +/- 0.18 ng/10(6) platelets. Patients with thrombocytopenia had approximately normal PAI-1 concentrations in PFP; the extremely low concentrations in serum or PRP reflected the platelet count. A patient with grey platelet syndrome showed a comparable pattern, confirming that PAI-1 occurs in the platelet alpha-granules and indicating that the plasma concentration of PAI-1 is independent of the platelet pool of PAI-1. The median inhibitory activities towards t-PA were 1.6, 8.7 and 8.3 units/ml in normal PFP, PRP and serum respectively. PAI-1 in PFP had a median specific activity (units/mg PAI-1) about 5-fold higher than platelet PAI-1. Plasma and platelets represent two distinct pools of PAI-1, both of which should be considered in studies on the relationship between circulating PAI-1 and thrombotic disease.
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An inhibitor of plasminogen activator was purified to apparent homogeneity from human umbilical vein endothelial cell conditioned medium. The purification was achieved by a speedy and simple two-step procedure, without the use of denaturants. The purified protein was a single-chain glycoprotein with apparent molecular mass of 48 kDa. The purified inhibitor had a specific activity of 8500 U/mg protein and the activity could be stimulated about fourteenfold by treatment with denaturants. An antiserum to the purified inhibitor was raised in rabbits. It recognised plasminogen activator inhibitor from platelets and plasma as well as from cultured endothelial cells. The immunoglobulin fraction of the antiserum neutralised the functional activity of the inhibitor from all these sources.
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