Enhanced Blood Coagulation and Fibrinolysis in a Patient with Primary Amyloidosis

A case of primary amyloidosis associated with blood coagulation abnormalities is presented. Enhancement of coagulation, suspected because of acceleration of the thromboplastin activation test and of abnormal thrombelastography patterns, was confirmed by the presence of thrombi observed at necropsy. Increased systemic fibrinolysis was evidenced by accelerated clot lysis, increased euglobulin activity, and decreased plasminogen. The presence of fragmented red cells in the peripheral blood smear was consistent with a microangiopathic process. Despite these abnormalities, there were no major changes in levels of coagulation factors. Episodes of massive bleeding occurred when major changes in coagulation or fibrinolysis were absent, supporting the suggestion that vascular infiltration by amyloid is a major cause of hemorrhage.

Plasma Levels of TNF- in Sickle Cell Patients Receiving Hydroxyurea

Hydroxyurea (HU), a chemotherapeutic agent, used increasingly in the treatment of sickle cell disease (SCD) stimulates the release of a tumor necrosis factor (TNF-alpha) from human macrophages in vitro and the concentration of TNF-alpha is greater than normal in subjects affected by SCD. It is widely accepted that HU may inhibit vaso-occlusive crisis (VOC) by stimulating the production of fetal hemoglobin (HbF) and nitric oxide (NO) in SCD; however, the beneficial effects of HU in vivo may be counteracted by the release of TNF-alpha and, in turn, the expression of a vascular cell adhesion molecule (VCAM-1) on leukocytes. Previous studies have shown that the severity of SCD increases with the leukocyte count. Therefore, we examined the relationship between plasma levels of TNF-alpha and HbF in SCD patients during steady-state (StSt) conditions (in the absence of VOC) and during VOC conditions after the acute administration of HU. Venous blood was collected in SCD patients over 6 h after administering a single dose of HU. Plasma TNF-alpha was found to be greater in SCD subjects than in reported normal adult controls (p<0.05). TNF-alpha in the StSt group was not significantly different than in the VOC group; however, the plasma TNF-alpha tended to greater in the VOC group (p>0.1). An increase in the HbF concentration after acute administration of HU (p<0.01) was not associated with a significant change in plasma TNF-alpha (p>0.1). Contrary to the results of in vitro studies, HU did not increase the plasma concentration of TNF-alpha. These findings suggest that a HU-induced increase in TNF-alpha does not contribute to VOC and sickle cell patients can be counseled that the HU-induced increase in TNF-alpha does not counteract the beneficial effects of HU in SCD.

Arterialization of Venous Blood for Differentiation of Sickle Cell Subjects in Vaso-occlusive Crisis

These studies were designed as two experiments. Experiment 1 was performed to validate the hypothesis that oxygen saturation of the venous blood may be a marker for vaso-occlusive crisis (VOC) in sickle cell patients undergoing hydroxyurea (HU) treatments. Experiment 2 was performed to test the hypothesis that an acute increase in the blood nitric oxide (NO) concentration by administering HU modulates the perception of pain in sickle cell subjects in VOC. The percent saturations of oxyhemoglobin (%O<PRE>2</PRE>Hb), reduced hemoblogin (%RHb), carboxy-hemoglobin (%COHb), met-hemoglobin (%MHb), fetal hemoglobin (HbF), and nitric oxide metabolites were measured in venous blood samples collected from sickle cell disease (SCD) who were on and off HU and O<PRE>2</PRE> at steady state and during VOC. The results showed the ratio of %O<PRE>2</PRE>Hb/RHb in VOC+HU was significantly higher than patients in the steady state who were on and off of HU (p<0.05). The %COHb was higher in all SCD groups, %COHb values were significantly different in SCD at steady state who were on HU. HU and O<PRE>2</PRE> treatment did not play important role on venous blood %O<PRE>2</PRE>Hb and pain scores in SCD during VOC. A single oral dose of HU was associated with a significant increase in the venous concentration of nitric oxide metabolites (NOx), p<0.05. These findings suggest that the ratio %O<PRE>2</PRE>Hb/RHb in venous blood and pain scores differentiate HU-untreated and HU-treated at steady state subjects from HU-treated subjects in VOC; however, the acute increase in venous NOx produced by administering HU to HU-treated subjects in VOC does not explain this difference.

Effect of transfusion on cerebral oxygenation, flow velocity in a patient with sickle cell anemia and Moyamoya disease: a case report

Vascular occlusive diseases affect brain blood flow, brain metabolism and are associated with arterial ischemic stroke. This study was designed to measure the brain blood flow velocity, brain oxygenation, hemoglobin concentrations, hematocrit, and cell free hemoglobin at pre- and post-exchange red cell transfusion in an 18 year old male patient with sickle cell disease and moyamoya syndrome (MMS). Exchange transfusion increased cerebral oxygen saturation 12%, total hemoglobin concentration 2%, hemoglobin AA 80%, and reduced sickle (SS) hemoglobin 12%, arterializations 33%, and cell free hemoglobin 33%. Brain blood flow velocity values were unaffected by transfusion. These observations suggest that exchange transfusion increases the hemoglobin carrying capacity and reduces sickle hemoglobin and shunting of blood, which may improve the peripheral and cerebral oxygenation. Transfusion did not affect the brain blood flow in this patient. Therefore the risk of transient ischemic attack and arterial ischemic stroke from mms still exist.

Long-term outcomes in patients with sickle cell disease and frequent vaso-occlusive crises

BACKGROUND

The frequency of vaso-occlusive crises correlates with mortality in patients with sickle cell disease (SCD). We examined the degree to which a high number of hospitalization days for these events affected survival.

PATIENTS AND METHODS

We reviewed data for 58 adult patients with SCD (mean age, 29.9 +/- 7.3 years) treated at our hospital between 1986 and 1994 who had at least 100 hospitalization days during any of these years. Their mean follow up period was 6.65 years (median, 6.84 years; range, 0.15-14.51 years).

RESULTS

Thirty-five patients (60.3%) died during follow-up. In multivariate analysis that included age, gender, and numbers of transfusions and hospitalization days, only age was significantly associated with mortality. The National Cooperative Study of Sickle Cell Disease (CSSCD) estimates the 10-year mortality at 15% for all 20-year old SS patients and also for all 30-year-old women. For 30-year-old men, the CSSCD estimated a 10-year mortality of about 28%. Thus, the 60.3% mortality of our patients after a median follow-up of only 6.84 years was substantially higher. Fifty-one patients were still alive after 1992, when hydroxyurea became available for SCD. The median survival of 15 hydroxyurea-treated patients was 7.3 years, compared with 4.3 years in 36 patients who did not take the drug.

CONCLUSIONS

Mortality for patients with SCD with a high number of hospitalization days was much higher than that expected for patients with SCD in general. There was a (nonsignificant) trend for longer survival in these severely ill patients if they took hydroxyurea.

Nitric oxide and cyclic GMP levels in sickle cell patients receiving hydroxyurea

Recent studies suggest that nitric oxide (NO) may partly be responsible for the beneficial effect of hydroxyurea (HU) in sickle cell disease (SCD) patients. NO stimulates cyclic guanosine monophosphate (cGMP) production, which mediates vasodilatation. We investigated the association between NO, cGMP and fetal haemoglobin (HbF) levels after HU administration. Our data showed that chronic HU significantly increased NO, cGMP, and HbF levels in SCD. Recently it was shown that HbF production was stimulated by cGMP-dependent protein kinase. Our results suggest that NO stimulates cGMP production, which then activates a protein kinase and increases the production of HbF.

Arterialization of peripheral venous blood in sickle cell disease

Arterialization of the venous blood is thought to be indicative of cutaneous shunting, and occurs in patients with sickle cell disease (SCD) during vaso-occlusive crisis (VOC). We performed the present study to quantify the amount of shunting that occurs in sickle cell patients presenting at the Howard University Sickle Cell Center, Washington, D.C., as outpatients and for hospitalizations associated with sickle cell crisis. Peripheral venous blood was drawn anaerobically into heparinized syringes from 9 normal control subjects (NC), 24 outpatients (steady-state group), and 14 inpatients during crisis (VOC group). Spectrophotometric measurements were made for the following species of hemoglobin (Hb): oxy-Hb (O2Hb), reduced Hb (RHb), carboxy-Hb (COHb), and met-Hb (MHb). In addition, fetal hemoglobin (HbF) was measured by high-pressure liquid chromatography (HPLC). The O2Hb saturations of the steady state group were not significantly different than those of the NC group (55 +/- 4% vs. 40 +/- 6%). However, the O2Hb saturations of the VOC group were 73 +/- 3%, and this value was found to be significantly greater than those of both the steady-state and the NC groups (p < 0.05). Reduced hemoglobin saturations were inversely related to the O2Hb values, as expected. Compared to the NC group, the steady-state, and VOC groups had greater dyshemoglobin (COHb and MHb) levels (p < 0.05). These findings suggest that the percentages of venous O2Hb and dyshemoglobins may be increased in sickle cell disease even in the absence of VOC. Therefore, the venous O2Hb saturation may be a useful biochemical marker for the arteriovenous shunting and hemodynamic adaptations associated with sickle cell disease.

Nitric Oxide Metabolites in Sickle Cell Anemia Patients after Oral Administration of Hydroxyurea; Hemoglobinopathy

The mechanism of action of hydroxyurea (HU) in decreasing the frequency of pain crisis in sickle cell disease (SCD) has not been fully elucidated. In vitro and in vivo studies suggest that nitric oxide (NO), a potent vasodilator, may partly be responsible for the beneficial effect of HU. This study was designed to determine the effect of oral administration of HU on plasma levels of NO metabolites (NO(x) ) in sickle cell patients (SCP). The results indicate that during steady-state plasma levels of NO(x) were significantly higher in HU-treated patients compared to non HU-treated patients or normal controls (p <.05). In five inpatients in mild pain plasma levels of NO(x) increased significantly after 2 h of HU administration (p <.05); however, in three inpatients in persistent pain with significantly lower baseline NO(x) there was a minimal NO(x) response to HU at 2 h (p <.01). These observations indicate that HU administration is associated with the production of NO in some SCP, but that further study of the pharmacodynamics of this effect is necessary.

Homocysteine in sickle cell disease: relationship to stroke

PURPOSE

The risk factors and pathophysiology of stroke and other serious complications of sickle cell disease (SCD) are poorly defined. Hyperhomocysteinemia has recently been identified as a risk factor for stroke and other vascular diseases in the general population, however its role in SCD has not been investigated.

PATIENTS AND METHODS

We measured serum homocysteine and red cell folate levels in 100 patients with SCD, including 16 patients with stroke. A disease severity score was determined for all patients and those without stroke were classified into mild (44 patients) or severe (40 patients) disease groups.

RESULTS

Homocysteine levels for the stroke group (median 13.3 mumol/L, mean 13.1 +/- 4.3 mumol/L) were significantly higher than those in patients without stroke (median 9.7 mumol/L, mean 10.7 mumol/L) (P < 0.02), and on multiple regression analysis homocysteine level was independently correlated with stroke (P < 0.026). Homocysteine and folate levels were inversely correlated (r = -0.41, P < 0.00005). Using logistic regression, the odds ratio for stroke in patients with homocysteine levels above the median (10.1 mumol/L) was 3.5 in this group of patients (95% confidence interval 1.1 to 11.9).

CONCLUSION

High homocysteine levels may be a risk factor for development of stroke in SCD patients. The role of homocysteine in the pathogenesis of stroke in SCD needs to be examined in a longitudinal, prospective study.

Cancer incidence rate and mortality rate in sickle cell disease patients at Howard University Hospital: 1986-1995

The incidence of cancer in patients with sickle cell disease (SCD) is not known. The 10-year follow-up data on 696 patients with SCD was analyzed at our institution in order to determine the cancer incidence and cancer mortality rates. The age range was 18 to 79 years, with a mean age of 28.8 years. There were 377 females and 319 males. The median follow-up was 3 years. Five patients developed cancer during this period. The cancer incidence rate was 5/2,864 or 1.74 per 1,000 patient years. The 95% CI was 0.64 to 4.32 per 1,000 patient years. There were 68 deaths with 3 being due to cancer. The cancer mortality rate was 3/2,873 or 1.04 cases per 1,000 patient years. Our data represent the first published paper that the authors are aware of, where the cancer incidence and mortality rates have been calculated for any group of patients with SCD.

The impact of health insurance on an African-American population with colorectal cancer

This study evaluates the impact of health insurance as a substitute for social class on tumor location, presentation, stage, grade, and age-adjusted survival in an African-American population. Patients were stratified by insurance into two groups: group 1 (private insurance and Medicare parts A & B) and group 2 (Medicaid, Medical Charity, self-pay, uninsured, or unemployed). A total of 212 patients were evaluated. Of these, 210 patients were insured or had Medical Charity, and two were uninsured. The type of health insurance did not significantly affect age-adjusted survival. However, age and stage at presentation were positive predictors of age-adjusted survival. Higher socioeconomic status was associated with group 1 health insurance.

Enhancement of pain control with ketorolac tromethamine in patients with sickle cell vaso-occlusive crisis

Twenty one patients with sickle cell disease admitted to the hospital with the pain of vaso-occlusive crisis (VOC) were treated by continuous IV infusion of ketorolac or normal saline for up to 5 days. All patients received supplemental IM injections of meperidine, 100 mg, as necessary, but not more frequently than every 3 hr. Over the 5 days the ketorolac treated patients (KT) required 33% less meperidine than did the placebo treated patients (PL), P = 0.04, and had significantly better pain relief as assessed by categorical, visual analog, and pain relief scales. By the end of 5 days infusions had been discontinued in six KT and one PL. The time to discontinuation of the infusion was significantly shorter in KT, (P = 0.009). The median duration of hospital stay from the start of treatment was 3.3 days for KT and 7.2 days for PL, P = 0.027. Adverse events were mainly related to the digestive system. This study showed that continuous infusion of ketorolac significantly reduced total meperidine requirement and that the analgesia produced by this combination was superior to that produced by meperidine alone. Further evaluation of this drug in the management of sickle cell VOC is warranted.

Erythropoietin: a review

The fact that a plasma factor was responsible for the stimulation of red cell production has been known for more than 35 years. However, it is only recently that the gene responsible for its production and its molecular structure has been identified. Furthermore, recombinant human erythropoietin is now available for clinical use. This article details the molecular biology and clinical pharmacology of this remarkable growth factor.

Preventing falls in the elderly. A practical approach to a common problem

Considerable morbidity and mortality occur among the elderly every year in the United States as a result of falls. Assessing the risk of falling with use of thorough history taking, physical examination, and special tests of balance and gait allows physicians to make specific safety recommendations.

The impact of pulmonary infections on the survival of lung cancer patients

To determine the impact of pulmonary infections on survival in patients with lung cancer, a retrospective review of the records of 121 such patients treated at Howard University Hospital in Washington, DC, was done. There were 77 men and 44 women; 118 were black. The mean age was 63.5 years. Forty-three patients had squamous cell carcinoma, 31 had adenocarcinoma, 18 had large cell carcinoma, 19 had small cell carcinoma, and ten were unclassified. The stages were as follows: two patients in Stage 0, 15 in Stage I, seven in Stage II, 45 in Stage III, and 44 in Stage IV. Eight patients could not be staged at diagnosis. Eighty-five patients (70%) had documented infections; 37 had single episodes; and 48 had more than one. The five most common organisms recovered were alpha/gamma streptococci, Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter aerogenes, and Pseudomonas aeruginosa. The median survival of all infected patients was 4.2 months which was significantly shorter than that of uninfected patients who had a median survival of 12.9 months (P less than 0.05). When Stage III patients were analyzed separately, infected patients lived a median of 5.8 months and uninfected patients, 13.4 months (P less than 0.05). This study indicated that pulmonary infections frequently occur in patients with lung cancer and suggested that they may adversely affect survival.

Patient-controlled analgesia in patients with sickle cell vaso-occlusive crisis

Pain control using intramuscular analgesia is often unsatisfactory in sickle cell patients. In a pilot study, 15 patients with sickle cell anemia (SS) and one patient with SB thalassemia in vaso-occlusive crisis were treated with the Patient-Controlled Analgesia (PCA) technique using a Pharmacia Deltec Programmable pump (CADD PCA). Age range was 19-50 years (median = 27); there were nine females and seven males. The protocol consisted of 3 days of therapy using a background of continuous infusion meperidine. The starting dose was 20 mg/hr and was escalated to 30 mg/hr. The average amount given was 25.8 mg/hr. One to two boluses of 2.5-5.0 mg/dose (mode = 5.0) were also allowed each hour. In addition, patients number 8 through 16 were given hydroxyzine (Vistaril) 50 mg PO q6h. The number of days in pain prior to study entry (mean +/- SD) was 3.3 +/- 1.6. The number of pain sites per patient was 3.6 +/- 1.2. Using categorical and analog pain scales, patients' pain scores decreased only about 30%. However, most patients were fairly satisfied with the treatment and rated it overall as follows: 1 poor, 1 fair, 3 good, 6 very good, 4 excellent, 1 no comment. Patients number 8 through 16 gave higher ratings probably because a more idealized dosage regimen was being used by that time in the study. There were no adverse effects or major problems noted. It is our impression that PCA, when optimized, will be a safe and effective alternative method for providing patients with sickle cell vaso-occlusive crisis pain relief.

Acute promyelocytic leukemia following treatment of non-Hodgkin's lymphoma

A case of acute promyelocytic leukemia (APL) 3 years following the treatment of diffuse mixed non-Hodgkin's lymphoma (NHL) is presented. This is the second time APL after NHL has been reported in the literature.

Severe hepatotoxicity from Escherichia coli L-asparaginase

A 51-year-old black woman with diabetes mellitus developed severe hepatotoxicity after receiving high-dose L-asparaginase (Elspar) for acute lymphatic leukemia. Patients with diabetes should be given this drug cautiously. Glutaminase-free L-asparaginase from Vibrio succinogenes has been reported to be less hepatotoxic in mice; it might be a safer product for this group of patients.

Increased cancer risks in blacks: a look at the factors

Incidence and mortality rates of cancer in blacks have been increasing at a faster rate than in whites. In particular, recent incidence rates of lung cancer in black men have increased, while the rates in white men decreased for the first time since 1982 to 1983. This leveling off in incidence for whites may suggest the beginning of a downturn in lung cancer because the smoking prevalence has decreased substantially since 1965.There is considerable evidence that cancer risks in blacks are higher than in whites. The major risk factors to cancer include cigarette smoking, diet, alcohol, and occupational exposure to industrial carcinogens. Other factors, including immunogenetic and unknown risks, might be associated partially with an increased incidence of cancer in blacks. Analytic epidemiologic studies addressing the relationship between genetic factors, or biomarkers, and cancer along with epidemiologic methods are warranted. Key factors that contribute to the prevention of cancer mortality should be identified and promulgated through primary or secondary cancer prevention programs.

Clinical pharmacokinetics: a simplified approach, Part 2

Part 1 of this two-part series in clinical pharmacokinetics (J Natl Med Assoc 1985; 77:475-482) introduced the clinician to the basic principles required for rational therapeutic drug management at the bedside. Practical problems were included that demonstrated how these principles could be put to clinical use.In Part 2 the clinical pharmacology of three commonly used drugs (theophylline, digoxin and gentamicin) are discussed, and practical problems are presented to illustrate the use of their pharmacokinetic profiles.

Clinical pharmacokinetics: a simplified approach, Part 1

Clinicians often find that the application of pharmacokinetic principles for the calculation of a drug regimen is bewildering and difficult. In this article it is shown that clinically useful calculations can be simply done at the bedside using a handheld calculator. The only requirement is an understanding of the terms that define the pharmacokinetic behavior of a drug. Appropriate manipulation of these terms will allow calculation of loading and maintenance doses, peak and average plasma concentrations, and other useful pharmacological data. The result will be improvement in drug therapy.

Disposition and bioavailability of various formulations of tetrahydrocannabinol in the rhesus monkey

Oral delta 9-tetrahydrocannabinol (THC) in gelatin capsules is under evaluation as an antiemetic agent in cancer patients, but knowledge concerning its bioavailability is incomplete and, furthermore, alternative routes of administration may be desirable. In this study, the disposition of THC was determined in four rhesus monkeys given 2.5-mg/kg doses using the following routes of administration and formulations: intravenous (iv); orally (po) on a cookie and in gelatin capsules; intramuscularly (im) in Tween-80 and in Emulphor-EL620; rectally in various suppository bases. Serum THC concentrations were measured by RIA and analyzed by weighted nonlinear regression. Serum concentrations were best described by a sum of two exponentials with alpha and beta half-lives (mean +/- SD) of 0.74 +/- 0.59 and 14.9 +/- 12.5 h. Apparent bioavailability (%F +/- SD) of various formulations of THC were: gelatin capsules, 26 +/- 14; cookie, 89 +/- 16; intramuscularly in Tween-80 and in Emulphor, 39 +/- 13 and 102 +/- 15, respectively. Using the method of statistical moments, mean residence times in the body (h +/- SD) were: intravenous, 6.08 +/- 1.60; cookie, 21.92 +/- 3.11; gelatin capsule, 26.80 +/- 23.61; intramuscularly in Emulphor, 10.92 +/- 3.46 (in Tween-80, not calculated). THC was not bioavailable by the rectal route. We conclude from this study that THC formulated as a gelatin capsule exhibits a low and variable extent of bioavailability and that intramuscular THC may be a useful alternative route of administration since it is more completely bioavailable.