Thrombosis and hemorrhage in oncology patients

As outlined in this review, patients with cancer may harbor many alterations of hemostasis. These are multifaceted and must be considered when trying to control hemorrhage or thrombosis in cancer patients. Also, hemorrhage or thrombosis is often the final fatal event in many patients with metastatic solid tumor or hematologic malignancies. Patients with malignancy present a major clinical challenge in this new era of oncologic awareness and more aggressive care, which has led to prolonged survival for patients and a longer time frame during which these complications may develop. Therefore, these complications are occurring more commonly. It is important to realize that these alterations of hemostasis exist and must be approached in a sequential and logical manner with respect to diagnosis; only in this way can responsible, efficacious, and rational therapy be delivered to patients. By far the most common alteration of hemostasis in malignancy is that of hemorrhage associated with thrombocytopenia, either drug-induced, or radiation-induced, or from bone marrow invasion. Hemorrhage resulting from DIC, however, is also quite common and may present as hemorrhage, thrombosis, thromboembolus, or any combination thereof. Many antineoplastic drugs and radiation therapy may lead to or significantly enhance hemorrhage in patients with malignancy. Thrombosis, also commonly seen in patients with malignancy, is often a manifestation of low-grade DIC. When approaching the patient with malignancy and either hemorrhage or thrombosis, all the potential defects in hemostasis must be considered, defined from the laboratory standpoint, and treated in as precise and logical manner as possible.     

Variability in mammography use among older women

OBJECTIVE: To determine rates of and explore factors associated with mammography use among older women. DESIGN: Retrospective review of part B (physician) bills submitted to Medicare during 1990. SETTING: Health Care Financing Administration (HCFA) data, including sociodemographic information and part B physician bills for all services delivered to Medicare-eligible women in 1990. PATIENTS/PARTICIPANTS: Women age 65 or older as of January 1, 1990, residing in one of 10 states with part B coverage through December 31, 1990. MEASUREMENTS AND MAIN RESULTS: The outcome was receipt of a mammogram (yes/no). We explored factors associated with mammography use within three age groups: 65 to 74, 75 to 84, and 85+. The factors considered were race, state, median income of ZIP Code of residence (from the 1990 US Census, and used to divide the population into quintiles within each state), and number of primary care visits (0, 1, 2, and 3+). Overall, 15% of women had a mammogram: 20% of women age 65 to 74, 12% of women age 75 to 84, and 4% of women age 85 and older. Mammography use was lowest in Oklahoma and highest in Washington. However, in each state the older the age category, the less the mammography use (e.g., 9% vs 5% vs 2% in Oklahoma and 25% vs 16% vs 5% in Washington for women 65-74, 75-84, and 85+, respectively). Mammography use was lower for black than for white women age 65 to 74 (14% vs 21%, P < .001) and 75 to 84 (9% vs 12%, P < .001). Women in each of these two age groups had lower mammography use if they resided in the lowest income quintile and highest if they resided in the highest income quintile (17% vs 23% 65-74, and 10% vs 13% 75-84, P values < .001). Among the oldest women (those 85+), mammography use was low (4%) and varied minimally by race and income (P = .907 and .003, respectively). In all age groups, mammography use was lowest among women who did not have a primary care visit, was greater among women who had at least one visit, and continued to rise with increasing numbers of visits (all P values < .001). For example, among women age 75 to 84, mammography use increased from 5% to 10%, 14%, and 17% for those with 0, 1, 2, and 3+ visits. CONCLUSIONS: We found that mammography use was less for women who were older, of black race, who did not visit a primary care provider, and who lived in areas with lower median income and certain geographic locations (states). Similar factors influenced mammography use in women age 65 to 74, where there is greater consensus as to who should receive a mammogram, and women age 75 to 84, where there is neither consensus nor data. Surprisingly, neither race nor income had much influence on mammography use among women age 85 or older.     

Preliminary clinical outcome and imaging criterion for endovascular prosthesis development in high-risk patients who have aortoiliac and traumatic arterial lesions

PURPOSE: This report reviews our preliminary experience of prospective treatment of arterial lesions with endoluminal grafts in a Food and Drug Administration (FDA)-approved, investigator-sponsored Investigation Device Exemptions study. The utility and accuracy of various imaging methods, including angiography, cinefluoroscopy, computed tomography (CT), intravascular ultrasonography (IVUS), and duplex scanning, in performing the procedures was also assessed. METHODS: Thirty-one patients were evaluated; 17 patients were treated, including 11 with abdominal aortic aneurysms, one with an aortic occlusive lesion, two with iliac artery aneurysms, and three with traumatic arteriovenous fistulas. Twelve of the 14 patients who had aorta and iliac artery lesions were high-risk. The mean follow-up of patients treated was 9 months (range, 6 to 15 months). RESULTS: Aortoaortic endoluminal interposition procedures were not successful for treating abdominal aortic aneurysms early in the study (n = 3). Aortoiliac endoluminal bypass, contralateral iliac artery occlusion, and femorofemoral bypass procedures were successful in seven of eight subsequent cases (88%), with no incidence of endoleaks at either the proximal or distal fixation sites using the deployment methods described in this report. The 30-day operative mortality rate on follow-up evaluations for patients who underwent aortoiliac procedures was 14% (two of 14). Other major complications included transient renal failure in three patients that required short-term (two to eight times) dialysis, one arterial perforation and one dissection, and one prolonged intubation. No myocardial infarctions or strokes occurred. After major complications or identification of limitations in the study, the protocol was modified with the approval of the FDA to help avoid the recurrence of the same problems. There were no deaths or complications in the trauma cases. CONCLUSIONS: Contrast-enhanced CT (axial images and spiral reconstructions) was the most accurate method to determine candidacy for aortoiliac procedures and to choose the site for deployment of the devices. Angiographic scans were misleading in several patients regarding the critical determinants of patient candidacy and device deployment, particularly regarding the presence of a distal aortic neck. Cinefluoroscopy was used in all patient and was particularly useful for determining the continuity of vascular structures and the anatomy of branch arteries and for enabling precise positioning of stent devices. Determination of fixation sites and assessing dimensional information by cinefluoroscopy and angiography were limited by inaccuracies produced by image magnification, parallax, and uniplanar views. IVUS was used to determine the morphologic features of vascular structures (i.e., calcium, thrombus), to perform real-time observation of the expansion of devices, and to assure firm fixation of balloon-expanded stents before the procedures were completed. Duplex scanning was very helpful in assessing and identifying precisely the location of arteriovenous fistulas before intervention and provided assessment at follow-up intervals. Three-dimensional reconstruction imaging technologies such as spiral CT were particularly helpful for assessing the morphologic features of vascular anatomy before the intervention and at follow-up intervals, whereas 3-D IVUS provided a similar real-time perspective during the procedure.     

The role of chemotherapy in head and neck cancer

We studied the effect of cytoreductive chemotherapy in head and neck cancer and analyzed it in terms of efficacy, remission rates, and duration, as well effect on survival. Single-agent chemotherapy, which formerly was used as a palliative therapy in recurrent and metastatic disease, had little affect on survival. More recently, multi-agent chemotherapy trials have shown significantly higher response rates, but this success has not translated into an added survival benefit. These findings led to the introduction of multi-agent chemotherapy into the induction (neoadjuvant) clinical setting. In these clinical circumstances, better objective response rates were found, particularly in the previously untreated patient. Although this therapy has resulted in better control of local disease, the impact on survival is not yet clear. Adjuvant chemotherapy is most useful in patients who have a high risk of relapse. Therapy appears to decrease its incidence, particularly at distant sites. Finally, chemoradiation trials have shown that this treatment provides a survival advantage, but at the cost of a significant increase in toxicity.     

N-ras mutations in radiation-induced murine leukemic cells

N-ras mutations were examined in DNA samples extracted from the spleen of CBA/Ca mice that developed myeloid leukemia (ML) following exposure to radiations of different qualities. A total of 17 ML cases, i.e. 5 cases of neutron-induced and 12 cases of photon- (3 gamma-ray and 9 x-ray) induced ML were included in the study along with 12 DNA samples from the bone marrow cells of control mice. Polymerase chain reaction-single strand conformational polymorphisms (PCR-SSCP) and the direct sequencing of PCR products were used to analyze three regions of the N-ras gene: (i) a 120 base-pair (bp) long portion of exon I (codons 2-37); (ii) a 103 bp long portion of exon II (codons 48-82); and (iii) a 107 bp long portion of exon III (codons 118-150). PCR-SSCP mobility shifts indicated mutations within only exon II of the N-ras gene. Such mutations were more prevalent in samples from mice exposed to fast neutrons. The exact type and location of these mutations were then determined by direct DNA sequencing. Silent point mutations, i.e. base transitions at the third base of codons 57 (GAC-->GAT), 62 (CAA-->CAC), or 70 (CAG-->CAA) were present only in mice that developed ML after exposure to fast neutrons. A base transversion at the third base of codon 61 (CAA-->CAC) was also observed in some ML cases. DNA sequencing demonstrated that ML samples contained normal as well as mutated DNA sequences. The higher frequency of N-ras mutations in neutron-induced ML suggested that fast neutrons are more effective in inducing genomic instability at the N-ras region of the genome. More importantly, N-ras mutations are not the initiating event in radiation leukemogenesis. This conclusion was supported by the finding that N-ras mutations were detected only in mice with an overt leukemic phenotype but not in mice with minimal tissue infiltration of leukemic cells, suggesting that the disease may be present prior to the presence of N-ras mutations. Alternatively, N-ras may be present in these mice but a large number of normal spleen cells in these mice interferes with the detection of mutation in a small population of leukemic cells.     

Design of inhibitors of glycogen phosphorylase: a study of alpha- and beta-C-glucosides and 1-thio-beta-D-glucose compounds

alpha-D-Glucose is a weak inhibitor of glycogen phosphorylase b (Ki = 1.7 mM) and acts as a physiological regulator of hepatic glycogen metabolism. Glucose binds to phosphorylase at the catalytic site and results in a conformational change that stabilizes the inactive T state of the enzyme, promoting the action of protein phosphatase 1 and stimulating glycogen synthase. It has been suggested that, in the liver, glucose analogues with greater affinity for glycogen phosphorylase may result in a more effective regulatory agent. Several alpha- and beta-anhydroglucoheptonic acid derivatives and 1-deoxy-1-thio-beta-D-glucose analogues have been synthesized and tested in a series of crystallographic and kinetic binding studies with glycogen phosphorylase. The structural results of the bound enzyme-ligand complexes have been analyzed, together with the resulting affinities, in an effort to understand and exploit the molecular interactions that might give rise to a better inhibitor. This work has shown the following: (i) Similar affinities may be obtained through different sets of interactions. Specifically, in the case of the alpha- and beta-glucose-C-amides, similar Ki's (0.37 and 0.44 mM, respectively) are obtained with the alpha-anomer through interactions from the ligand via water molecules to the protein and with the beta-anomer through direct interaction from the ligand to the protein. Thus, hydrogen bonds through water can contribute binding energy similar to that of hydrogen bonds directly to the protein. (ii) Attempts to improve the inhibition by additional groups did not always lead to the expected result. The addition of nonpolar groups to the alpha-carboxamide resulted in a change in conformation of the pyranose ring from a chair to a skew boat and the consequent loss of favorable hydrogen bonds and increase in the Ki. (iii) The addition of polar groups to the alpha-carboxamide led to compounds with the chair conformation, and in the examples studied, it appears that hydration by a water molecule may provide sufficient stabilization to retain the chair conformation. (iv) The best inhibitor was N-methyl-beta-glucose-C-carboxamide (Ki = 0.16 mM), which showed a 46-fold improvement in Ki from the parent beta-D-glucose. The decrease in Ki may be accounted for by a single hydrogen bond from the amide nitrogen to a main-chain carbonyl oxygen, an increase in entropy through displacement of a water molecule, and favorable van der Waals contacts between the methyl substituent and nonpolar protein residues.(ABSTRACT TRUNCATED AT 250 WORDS)